JPH10114869A - Pigment for coating meterial and production of coating material containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a pigment which is reduced in cost of transportation and storage and in the pollution of a working environment and can give a coating material improved in blackness, gloss and tinting strength by pressing powdery and/or granular carbon blacks under specified pressure. SOLUTION: A carbon black such as furnace black or acetylene black is pressed into a molding, and this molding is used as a material for a coating material. The carbon black has a particle diameter of 1-60nm and a DBP absorption of 40-150ml/100g. This is placed in a metal, resin, composite material or ceramic mold and pressed under a pressure of 2-500kgf/cm<2> to obtain a molding having a density ρ(g/cc) equal to or larger than ρ=8.190×10<-3> D -3.824×10<-3> L+0.516 and equal to or lower than ρ=3.265×10<-3> D -3.334×10<-3> L+1.173 (wherein, D (nm) is the arithmetic mean particle diameter of the carbon black as determined by using an electron microscope; and L (ml/100g) is the DBP absorption of the carbon black). This molding is ground to a degree of powdering of 40% or below, and the product of grinding and a varnish, a solvent or the like are kneaded to obtain a coating material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pigment for paint made of carbon black and a method for producing a paint using the pigment. Fill the mold with carbon black,
By producing a paint using a molded product obtained by pressure molding at a specific pressure as a pigment, the obtained paint can significantly improve blackness, gloss, and coloring power. In addition, the pigment can significantly reduce transportation and storage costs, and can greatly reduce environmental pollution during use.

[0002]

2. Description of the Related Art Applied characteristics of a black paint using carbon black include blackness, color tone, viscosity / fluidity, and dispersibility. A black paint must have these characteristics in a well-balanced manner. Among these properties, blackness is particularly important. For example, in the carbon black handbook,
"As long as carbon black is used as a black pigment in coatings, the most important characteristic is its color, and it is desirable that the coating film has a deep blackness and a jet-black feeling. (Carbon Black Handbook, 3rd edition, P.580, issued by the Carbon Black Association). Thus, improvement in blackness is important, and various attempts have been made in the past. For example, there is an attempt to control the structure of carbon black itself, such as reducing the particle size of carbon black or reducing aggregates (lower structure and lower DBP oil absorption). However, in this case, if the particle size is smaller than 20 nm, the coloring power (the ability to mix carbon black with a white pigment to make it black, and desirably colored as little as possible) is reduced. Handbook 3rd edition
P.582 issued by the Carbon Black Association).
There are also attempts to adjust the surface properties of carbon black, such as lowering the pH of carbon black or increasing the amount of volatile components attached to the surface of carbon black.

It has been conventionally known that carbon black granules and flakes generally have higher blackness than ungranulated products. However, the degree of granulation, such as the density and hardness of particles, has been known. There is no technique for controlling the thickness and the like, and the relationship between these factors and characteristics such as blackness and the like developed by coating is not clear.

[0004] On the other hand, problems associated with the use of carbon black in general are that the cost required for transportation and storage is high due to the low bulk density of carbon black, and that environmental pollution due to dust generated when handling carbon black is extremely high. Was a big problem. On the other hand, conventionally, it has been attempted to increase the bulk density by granulating carbon black to obtain granules (including flakes). However, granules obtained by dry granulation or wet granulation, which are generally granulation methods, have a bulk density of 0.3 to 0.5 cc / g, which is considerably higher than that of untreated carbon black. Although the density is high, the suppression of powdering and dust generation during transportation and use is not yet sufficient. In addition, when the paint is used by granulation, the dispersibility in a varnish, a resin, or the like, which is a vehicle, is reduced, so that a granulated product may not be used. In this regard, according to the findings of the present inventors, it is conceivable that in the granulation step, the granulated product is granulated while long structures are entangled with each other, so that the dispersibility may be poor. Even in a flaked granulated product obtained by compressing carbon black by a roller compactor or the like, pulverization and suppression of dusting at the time of use or the like are not sufficient, and voids between carbon black granulated materials are 40 to 50. % Is inevitable, and it was difficult to increase the apparent bulk density even if the density of the granules themselves was increased.

[0005] As described above, the handleability of carbon black, particularly furnace black, which can be made to have a small particle size, that is, the ease of handling and the dispersibility in a vehicle are in a trade-off relationship, and the handleability and the dispersibility are simultaneously determined. The solution has been considered extremely difficult. For example, "Carbon Black Handbook <Third Edition>" (P.563) edited by Carbon Black Association states, "Carbon black with low contamination and excellent handling properties, easily dispersible carbon for further improving the production and quality of ink. The development of black is likely to be a major need. The handleability and dispersibility of carbon black are in conflict with each other, and there is a need to improve surface chemistry, rheology, carbon black form, packaging, shipping form, and other barriers. ] Is written,
In the carbon black industry, it is widely recognized that it is extremely difficult to simultaneously solve the handling property and the dispersibility, and various proposals have been made so far, but there is no example of simultaneously solving these two problems.

As described above, it has been considered extremely difficult to simultaneously satisfy the handleability of carbon black itself as a pigment and the dispersibility in a vehicle when used as a paint.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and found that a press-molded product obtained by pressurizing carbon black at a specific pressure and molding the same was used as a pigment for paints. By using as, the properties such as blackness, gloss, etc. in the obtained paint are improved, and simultaneously the above-mentioned handling properties and dispersibility can be simultaneously solved without pressure molding and expensive treatment of carbon black as a pigment, Further, they have found that such pigments have high versatility and are easy to use, and have reached the present invention. That is, the present invention provides a powder and / or granular carbon black of 2 to 500 k.
The present invention is directed to a paint pigment formed by press molding at gf / cm ² , and a method for producing a paint characterized by using such a pigment.

[0008] Further, the carbon black pressure-molded product of the present invention is a non-granulated product, a dry granulated product, a wet granulated product, and an oil-added granulated product in the form of products conventionally used. Even if the molded body is manufactured using the method described above and the density of the molded body is set to about 1.8 to 3.2 times the bulk density before molding, the dispersibility and gloss are not reduced. It became clear from the examination. Therefore, the bulk density can be sufficiently increased without sacrificing the dispersibility and the like, and the cost required for transporting and storing carbon black as a pigment can be significantly reduced. In addition, it is possible to prevent the carbon black, which is a pigment, from being powdered and dusted during handling, and to solve the problem of environmental pollution.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
First, in the present invention, carbon black is subjected to pressure molding to form a pressure molded body, which is used as a pigment for paint. As the carbon black to be subjected to pressure molding, those conventionally used for pigments can be used without limitation. For example, carbon black, acetylene black, lamp black, channel black, ketone produced by the furnace method, and the like can be used. Chain black, and the like. These various carbon blacks may be appropriately selected according to the properties of the intended coating material. For example, when a conductive paint is intended, Ketchen plaque is preferably used.

[0010] Of the carbon blacks described above, in particular, when a furnace black produced by the furnace method is used, a very remarkable effect is exhibited in maintaining the dispersibility. Further, the effect of improving the blackness and gloss of the obtained paint is also great. Further, those obtained by post-treating these various carbon blacks with various oxidizing agents and the like can also be used. These various carbon black powders and granules can be used without any particular limitation. Examples of the granules in this case include granules obtained by ordinary wet granulation and dry granulation, as described in, for example, JP-A-2-142858 and JP-A-3-193129. Flake carbon black obtained by using a roller compactor or the like.

The particle size of the carbon black is not particularly limited, but is particularly effective in improving the dispersibility and handleability in a small particle size range of 1 to 60 nm, especially 1 to 50 nm. It is also highly effective in improving Carbon black having a fine particle diameter in such a range has a strong cohesiveness between carbon blacks, and is particularly difficult to disperse when producing a coating material. Another advantage is that the more difficult these carbon blacks are to disperse, the more the advantages of the present technology can be exhibited. The basic characteristics of the carbon black, particularly the particle size and the DBP oil absorption, may be appropriately selected according to the characteristics of the intended coating material. Generally, the particle diameter is 1 to 80 nm, and the DBP oil absorption is 40 to 150 ml / 10.
It is about 0 g. When a paint requiring high blackness is intended, the particle diameter is 10 to 20 nm and the DBP absorption oil amount is 40 to 12
0 ml / 100 g is appropriate. General-purpose black paint has a particle diameter of 20 to 30 nm and a DBP oil absorption of 50 to 150 ml /
100 g is suitable. In addition, the pigment for paints of the present invention can be used for so-called toning in addition to black paints. In this case, a particle diameter of 30 to 80 nm and a DBP oil absorption of about 50 to 150 ml / 100 g are appropriate.

In the present invention, these carbon blacks are molded under pressure. At this time, a mold of any material may be used as long as it has a strength capable of withstanding an applied pressure during molding. For example, as a metal mold, SUS3
For example, a stainless steel mold such as 04, SUS316, etc., a carbon steel mold, and a super steel such as tungsten carbide can be used.
As the resin mold, polytetrafluoroethylene (PTF)
E) (trademark: “Teflon”), a mold made of a fluororesin such as poly (ethylene trifluoride chloride) (PCTFE), polytetrafluoroethylene / propylene hexafluoride (FEP), nylon,
Plastics such as polyethylene, polycarbonate and phenolic resin, and CFRP and GFR as composite materials
FRP such as P, ceramic molds include alumina,
Zirconia, mullite and the like can be used. By making the mold used for molding slidable, pressure molding can be easily performed.

[0013] The size of the mold is not limited, but practically, it is 1 cc or more, preferably 100 cc or more. If the amount is less than 1 cc, the transportation of carbon black becomes complicated. If necessary, a large molded body may be produced, cut into a suitable size, and transported and used as an aggregate. It is preferable that the volume of the obtained carbon black molded product is 1 cc or more, preferably 100 cc or more, because it is easy to handle.

The press used for pressurization includes a hydraulic mechanical press, a hydraulic hand press, a mechanical press,
Any press molding machine may be used as long as it can be press molded, such as an air cylinder press. The shape of the mold is also not particularly limited, and can be a columnar body having a triangular or other polygonal cross section, in particular, a cubic or rectangular parallelepiped molded body, according to a desired molded body shape, and is also preferable in terms of handling. It is. The carbon black is placed in the above-described mold and molded by pressing.

The pressure during molding under pressure (molding pressure) is 2 to
It is good to be 500 kgf / cm ² , preferably 5 to 400 kgf / cm ² . If the molding pressure is lower than ² kgf / cm ² , the compactness tends to decrease and the powdering rate tends to increase. On the other hand, when the molding pressure is higher than 500 kgf / cm ² , the dispersibility may not be sufficient with a dispersing machine used in the production of ordinary paints and the like. On the other hand, even if the pressure is further increased, the effect of improving compactness can hardly be obtained. For this reason, as a carbon black molded body used as a pigment when a paint is industrially manufactured, it is appropriate to perform pressure molding at ² to 500 kgf / cm ² . It is desirable that the density of the obtained molded body is in a range having the following relationship with the DBP oil absorption and the particle size of the carbon black to be used.

That is, the density ρ (g / cc) is calculated as follows: ρ = 8.190 × 10 ⁻³ D−3.824 × 10 ⁻³ L +
0.516 or more, ρ = 3.265 × 10 ⁻³ D−3.334 × 10 ⁻³ L +
1.173 It is preferable to set the following. More preferably, ρ = 8.686 × 10 ⁻³ D−4.031 × 10 ⁻³ L +
0.543 or more, ρ = 3.123 × 10 ^-3 D-3.189 × 10 ^-3 L +
1.072 or less is particularly preferable. Note that the density of the molded body is a value obtained by dividing the mass of the molded body by the volume of the molded body.

In each of the above formulas, D (nm) is the arithmetic average particle size of carbon black by an electron microscope, and L (m
1/100 g) is the DBP oil absorption. Here, the DBP oil absorption is a value measured by a method based on JIS K6221-1982. The particle size of the carbon black is a value measured by the method described below.
Put carbon black into chloroform and add 200KHz
Is dispersed for 20 minutes, and the dispersion sample is fixed to a support film. This is photographed with a transmission electron microscope, and the particle diameter is calculated from the diameter on the photograph and the magnification of the photograph. This operation is performed about 1500 times, and the values are obtained by arithmetic averaging.

When the density is in the above range, a molded article excellent in handleability can be obtained without impairing the basic properties of carbon black such as dispersibility in a vehicle. Further, it has an unexpected effect that the jetness when used in inks, paints and the like can be improved as compared with the raw material powder. These effects are particularly remarkably exhibited in the range described as the more preferable range described above. That is, when the density is smaller than the above range, the handleability and the dust prevention effect may not be sufficient. on the other hand,
If the density is greater than the above range, handleability,
The rate of further improving the dusting prevention effect is small, and the dispersibility in varnish tends to decrease.

It is particularly preferable that the carbon black molded article as the paint pigment of the present invention has a powdering ratio of 40% or less, more preferably 20% or less. The powdering ratio can be determined by the following measurement method. The carbon black press molded body is precisely weighed to 25 ± 1 g (W), and JI
200 mm in diameter and 1 aperture according to SK-6221
mm sieve. Attach a saucer and a lid to this sieve,
Shake for 20 seconds with a shaker according to SK-6221. Remove the pan from the shaker, accurately weigh the carbon nablack in the pan to 0.01 g,
This was the weight after shaking (W _R), to calculate the powdering ratio by the following equation. Powdering rate _{(%) = (W R /} W) × 100

By setting the pulverization rate to 40% or less, pulverization due to external force such as vibration or friction applied to the molded body during transportation can be prevented, and handling properties are particularly excellent. Further, the ratio of the bulk density of the powdery or granular carbon black subjected to the pressure molding to the density of the carbon black molded body (hereinafter, also referred to as “bulk density ratio”) is 2.5 to 8 times. Preferably, it should be 3 to 7 times. This bulk density ratio is 2.
When it is lower than 5, the compactness of the molded body tends to decrease. On the other hand, when the bulk density ratio exceeds 8, the dispersibility tends to decrease. When the bulk density ratio is 2.5 or more and 8 or less, compactness and dispersibility in varnish are simultaneously satisfied in an extremely preferable range. A paint is manufactured using the carbon black press-molded body described above as a pigment.
For the production of the coating material, a known method can be adopted except that the carbon black pressure molded body is used as a pigment.

The varnish (vehicle) used here is not particularly limited as long as it is used for a paint. For example, oil-based paints include drying oils, improved drying oils, natural resins, and bitumen. Alcohol paints include shellac, and cellulose derivative paints include nitrocellulose, acetylcellulose, acrylic resins, phenol formaldehyde resins, and resin-modified phenol formaldehyde resins. Oxidized oil-modified alkyd resin, modified alkyd resin, butylated amino alkyd resin, amino alkyd resin polyvinyl acetate,
Polyvinyl chloride, chlorinated rubber, styrene-butadiene resin, thermosetting acrylic resin, epoxy resin, unsaturated polyester, polyisocyanate resin, silicone and alkyd resin, butyl titanate, etc. -Butadiene and polyacrylic compounds are aqueous baking paints, phenol aldehyde prepolymers, etherified melanin resins, amine neutralized alkyd resins are aqueous paints, and aqueous paints are proteins, starch, alginates, polyvinyl alcohol, and paroxymethyl cellulose. For lacquer and the like, natural higher phenols and natural phenol aldehyde resins can be used.

Known solvents can be used without limitation, and examples thereof include toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, and water. In addition, various additives can be used. A known technique may be applied to the mixing ratio of these components. Specifically, usually, varnish (non-volatile component) is 20 to 40%, additive is several percent, and carbon black is about 0.5 to 5%.
The target paint is also not particularly limited.For example, as paint film main element classification, oil paint, oil enamel, phenol resin or maleic resin, alkyd resin paint, amino alkyd resin paint, urea resin paint, spirit paint, lacquer, vinyl Resin paints, acrylic resin paints, polyester resin paints, epoxy resin paints, polyurethane resin paints, silicone resin paints, emulsion resin paints, and water-soluble resin paints.

The use of the paint thus obtained is not limited, but it can be used, for example, as a back coat of a magnetic tape. In this case, the carbon black as a pigment is required to have properties such as conductivity, light-shielding property, and unevenness, and the carbon black may be appropriately selected according to the required properties. A urethane-based varnish is particularly preferably used. The method of dispersing the carbon black molded body, which is the pigment for a coating material of the present invention, in a vehicle is not particularly limited, and even if the carbon black molded body is used in the size as it is taken out of the mold used for molding, the size of the inlet of the kneading machine is sufficient. What has been crushed to a diameter of about 0.1 mm to 1 cm may be put into a kneader to make the following. Even when crushed ones are used, the effect of improving blackness and gloss can be exhibited. Here, the crushing method is not particularly limited. For example, if a shearing crusher such as a cutting mill, a rotary crusher, or a shearing roll mill is used, the density of the particles is not condensed at the time of crushing, which is preferable. .

The mechanism by which the paint pigment of the present invention improves characteristics such as blackness is not clear, but the following is presumed. That is, the mechanism by which carbon black is dispersed in the varnish is a process of replacing the solid-gas interface from the air-pigment interface to the pigment-dispersion medium interface with the solid-liquid interface. The interaction at the interface of the dispersion medium and the properties of the pigment solid surface play a major role. ”(“ Latest Pigment Application Technology ”(CMC Corporation)
Issue), p. 137), since the air between the carbon black particles is degassed by pressure molding in the coating pigment of the present invention, the solid-gas interface changes from the solid-gas interface to the solid-liquid interface. It is also presumed that the substitution of is easily performed. In any case, the use of the paint pigment of the present invention improves the handleability of carbon black as a pigment, prevents environmental pollution due to dust and the like during handling, and further reduces storage and transport costs, and at the same time,
An extremely epoch-making effect of greatly improving the dispersibility, blackness, and glossiness of the obtained paint can be achieved.

Next, the present invention will be described in more detail with reference to examples. In the following Examples and Comparative Examples, the dispersibility of carbon black in the produced black paint and the blackness and gloss of the coating film were evaluated. The evaluation methods for the respective properties are as follows. The evaluation of the dispersibility of the carbon black was carried out by performing a grind gauge measurement of the paint dispersed with a paint shaker for a predetermined time, and the value was used as an index of the dispersibility. The measurement of the grind gauge is based on the following method.
That is, a grind gauge is a steel plate having a depth of 0 to 25.
It is made by engraving two grooves varying up to × 10 ^-6 m.
The ink is placed at the deepest part, stretched shallower with a scraper, and the particle size is determined from the scale at the streak position formed at a position shallower than the diameter of the coarse particles. The blackness of the coating film was evaluated by a method using a color difference meter and a method using visual perception.

Evaluation of blackness by a color difference meter is based on JIS Z
The L value (brightness index) of the color difference formula of Hunter in 8730-1980 (color difference display method) was measured, and a sample having a small L value was judged to have a high blackness. The degree of blackness by visual perception was measured according to the following method. The paint prepared in the example and the paint prepared in the comparative example were arranged on a polyethylene terephthalate (PET) film, and stretched forward with a bar coater. A coating film having a thickness according to the setting of the bar coater is formed. The PET film coated with this paint is 12
The pieces were placed in a ventilation dryer set at 0 ° C. for 20 minutes to perform baking. Assuming that the blackness of the paint of the comparative example was 10 points, a large number was given to a sample having a higher blackness, and the blackness of the paint of the example was relatively compared.

The gloss was measured by visual feeling. The coating film prepared for the above blackness was inclined by about 60 degrees, and the degree of light reflection was measured visually. With the paint prepared in the comparative example as 10 points, a sample with higher gloss was given a larger number, and the gloss of the coating films of the examples was relatively compared. The coloring power refers to the ability to mix carbon black with a white pigment to make it black, and it is desirable that the carbon black can be colored in as small an amount as possible. As an evaluation method in the present Example and Comparative Example, the prepared black paint and white paint were mixed, applied to a PET film, and the baked coating film was measured for L value with a color difference meter. The evaluation was made by judging that the coloring power was high.

(Example 1) A mold made of SUS304 manufactured by Mitsubishi Kasei Engineering Co., Ltd. (inner method: 70 mm × 70 m)
m, height 40 mm), put 30 g of carbon black “# 2650” manufactured by Mitsubishi Chemical Corporation, and
37ton 4 pillar single acting hydraulic press (ram diameter 152.
4 mm). It was molded under pressure at a molding pressure of 1.9 kgf / cm ² and the molding density was measured.
Met. 2.5cc to 2.5cc in 140cc mayonnaise bottle
90 g of 5 mm glass beads manufactured by Tokyo Glass Co., Ltd. was placed. Melamine alkyd resin varnish (“Amirac 102
6 "16 g of Kansai Paint Co., Ltd., 10 g of Amirac Thinner (Kansai Paint Co., Ltd.) and 3 g of the above carbon black molded body were weighed and put. This mayonnaise bottle was set on a single type paint shaker “RC-5000A” manufactured by Red Devil Co., Ltd. and shaken for 15 minutes. After cooling this black varnish to room temperature,
Grind gauge manufactured by Ueshima Seisakusho (Model: "R111
0 "), the size of the undispersed mass carbon black in the range of 0 to 50 [mu] m was measured. The measurement result of the grind gauge was 15 μm.

Further, "Amirac 10" was added to this mayonnaise bottle.
26 Clear ”50g and 10 with a paint shaker
After mixing for a minute, a black paint was prepared. A part of this black paint was fractionated (about 1 cc), and the paint of Example 1 and the paint of Comparative Example 1 were applied to a PET film ("TRANSY G", thickness 180 μm) manufactured by Fuji Film Co., Ltd. at intervals of about 5 cm. It was put on and displayed with a bar coater (No. 24) manufactured by Toyo Seiki Co., Ltd. The rolled PET film was set at 120 ° C and a ventilation dryer manufactured by Ikeda Rika Co., Ltd. (“Automatic Drying Oven SS-2
00N ") for 20 minutes and baking was performed. The L value of the baked black coating film was measured by a color difference meter (“Spectro Color Meter SE-2000”) manufactured by Nippon Denshoku Co., Ltd. L
The value was 4.78. Further, the blackness of the sample of the example was evaluated by visual sensation with the blackness of the paint of Comparative Example 1 being 10. The blackness was 10+.

Further, the gloss of the sample of the example was evaluated by visual sensation assuming that the gloss of the paint of Comparative Example 1 was 10. The criteria for the evaluation are: "+ or-indicates a slight difference, 11 is slightly better, 12 is clearly better, and 13 or more is very good." As a result, the number of samples of Example 1 was 12. Next, a sample for evaluating coloring power was prepared. 140c
40 g of white paint “Amirac 1531 White” manufactured by Kansai Paint Co., Ltd. was weighed. Into this, 8 g of the black paint prepared above was put, and a paint shaker manufactured by Red Devil Co., Ltd. was used for 21 minutes (7 minutes × 3 times).
The mixture was mixed for use as an evaluation sample for coloring power. Using this sample, a coating film was formed on a PET film by the same operation as the black paint, and the L value was measured with a color difference meter manufactured by Nippon Denshoku Co., Ltd. L value is 4
4.9.

(Example 2) Except that the shaking time of the paint shaker in Example 1 was changed to 30 minutes, the same operation was performed. The measured value of the grind gauge was 9 μm, the L value of the black paint was 4.68, the blackness by visual perception was 10+, the gloss by visual perception was 11+, and the L value of the coloring evaluation sample was 41.
It was 7. Example 3 The same operation as in Example 1 was carried out except that the shaking time of the paint shaker was changed to 1 hour. The measured value of the grind gauge was 7.5 μm, the L value of the black paint was 4.48, the blackness by visual perception was 11 −, the gloss by visual perception was 12, and the L value of the coloring evaluation sample was 39.5. . (Example 4) Except that the shaking time of the paint shaker in Example 1 was changed to 2 hours, the same operation was performed. The measured value of the grind gauge was 7.5 μm, the L value of the black paint was 4.23, the blackness by visual perception was 10+, the gloss by visual perception was 10+, and the L value of the coloring evaluation sample was 39.6. Was.

Example 5 The same operation as in Example 1 was performed except that the molding pressure was changed to 372 kgf / cm 2. As a result, the molding density of the molded body was 0.842 g / cc.
Met. Also, as a result of measuring the paint prepared using this carbon black molded body, the measured value of the grind gauge was 15 μm, the L value of the black paint was 4.13, the blackness by visual perception was 11 −, and the gloss by visual perception was 15. The L value of the coloring strength evaluation sample was 39.7. (Example 6) Except that the shaking time of the paint shaker in Example 5 was changed to 30 minutes, the same operation was performed. The measured value of the grind gauge was 7.5 μm, the L value of the black paint was 4.33, the blackness by visual perception was 11, the gloss by visual perception was 12, and the L value of the coloring evaluation sample was 39.0.

(Example 7) Except that the shaking time of the paint shaker in Example 5 was changed to 1 hour, the same operation was performed. The measured value of the grind gauge is 7.5μ.
m, L value of black paint is 4.19, blackness by visual perception is 1
3. Luster by luminosity is 13, L value of coloring evaluation sample is 3
8.3. Example 8 The same operation as in Example 5 was carried out except that the shaking time of the paint shaker was changed to 2 hours. The measured value of the grind gauge was 8.0 μm, the L value of the black paint was 3.96, the blackness by visual perception was 12, the gloss by visual perception was 11, and the L value of the coloring evaluation sample was 38.3. (Comparative Example 1) Instead of the carbon black molded body used in Example 1, carbon black # 265 manufactured by Mitsubishi Chemical Corporation was used.
Except that 0 (bulk density: 0.077 g / cc) was used, the same operation as in Example 1 was performed. The measured value of the grind gauge was 17 μm, the L value of the black paint was 4.83, and the L value of the coloring evaluation sample was 45.8. The degree of blackness and gloss according to visual sensation were set to 10 as a reference.

Comparative Example 2 In place of the carbon black molded body used in Example 2, carbon black “# 2650” manufactured by Mitsubishi Chemical Corporation (bulk density: 0.077 g / cc)
The same operation as in Example 2 was performed except that was used.
The measured value of the grind gauge was 10 µm, the L value of the black paint was 4.76, and the L value of the coloring evaluation sample was 41.9. The degree of blackness and gloss according to visual sensation were set to 10 as a reference. (Comparative Example 3) Instead of the carbon black molded body used in Example 3, carbon black “#” manufactured by Mitsubishi Chemical Corporation was used.
Except for using "2650", the same operation as in Example 1 was performed. The measured value of the grind gauge was 7.5 μm, the L value of the black paint was 4.50, and the L value of the coloring evaluation sample was 3
9.7. The degree of blackness and gloss according to the visual perception is 10
And

(Comparative Example 4) The same operation as in Example 4 was performed except that carbon black "# 2650" manufactured by Mitsubishi Chemical Corporation was used instead of the carbon black molded body used in Example 4. . The measured value of the grind gauge was 8.0 μm, the L value of the black paint was 4.23, and the L value of the coloring evaluation sample was 39.7. The degree of blackness and gloss according to visual sensation were set to 10 as a reference. (Comparative Example 5) Instead of the carbon black molded product used in Example 5, carbon black dry granulated product "# 2650B" (bulk density 0.463 g / cc) manufactured by Mitsubishi Chemical Corporation
The same operation as in Example 5 was performed except that was used.
The measured value of the grind gauge was 19 μm, the L value of the black paint was 4.35, and the L value of the coloring evaluation sample was 43.4.

(Comparative Example 6) Except for using a carbon black dry granulated product “# 2650B” manufactured by Mitsubishi Chemical Corporation instead of the carbon black molded body used in Example 6, the same operation as in Example 6 was performed. Was carried out. The measured value of the grind gauge was 7.5 μm, the L value of the black paint was 4.46, and the L value of the coloring evaluation sample was 40.4. The degree of blackness and gloss according to visual sensation were set to 10 as a reference. (Comparative Example 7) The same operation as in Example 7 was performed except that a carbon black dry granulated product “# 2650B” manufactured by Mitsubishi Chemical Corporation was used instead of the carbon black molded body used in Example 7. The measured value of the grind gauge is 7.5
μm, L value of black paint is 4.29, L value of color strength evaluation sample
The value was 38.6. The degree of blackness and gloss according to visual sensation were set to 10 as a reference.

(Comparative Example 8) Except that the carbon black molded product used in Example 8 was replaced with a carbon black dry granulated product “# 2650B” manufactured by Mitsubishi Chemical Corporation, the same operation as in Example 8 was performed. did. The measured value of the grind gauge was 9.0 μm, the L value of the black paint was 4.01, and the L value of the coloring evaluation sample was 38.6. The degree of blackness and gloss according to visual sensation were set to 10 as a reference. Table 1 shows the results of these examples and comparative examples. Blackness of all samples of Examples 1 to 8,
The gloss and coloring power are equal to or higher than the corresponding comparative samples.

[0038]

[Table 1]

[0039]

According to the present invention, when a paint is produced using the paint pigment of the present invention comprising a specific carbon black molded body, the blackness, gloss, and coloring power of the paint can be greatly increased without requiring special treatment or expensive machinery. Can be improved. In addition, carbon black, which is a pressed pigment that is a pigment for paints, has a much higher density than powdered carbon black or granulated carbon black, which is a conventional product, so transportation and storage costs can be significantly reduced. In addition, the problem of environmental pollution during use can be solved.

Claims (14)

[Claims] 1. A pigment for paint obtained by press-molding powdery and / or granular carbon black at ² to 500 kgf / cm ² . 2. The density ρ (g / cc) is as follows: ρ = 8.190 × 10 ⁻³ D−3.824 × 10 ⁻³ L +
0.516 or more, ρ = 3.265 × 10 ⁻³ D−3.334 × 10 ⁻³ L +
1.173 or less (however, the arithmetic average particle diameter of carbon black by an electron microscope is D (nm), and the DBP oil absorption is L (ml / 1
00g)). 3. The density ρ (g / cc) is as follows: ρ = 8.686 × 10 ⁻³ D−4.031 × 10 ⁻³ L +
0.543 or more, ρ = 3.123 × 10 ^-3 D-3.189 × 10 ^-3 L +
1.072 or less (provided that the arithmetic average particle diameter of carbon black by an electron microscope is D (nm), and the DBP oil absorption is L (ml / 1
00g)). 4. The coating pigment according to claim 1, wherein the carbon black is obtained by a furnace method. 5. A carbon black having a DBP oil absorption of 40 to 40.
The paint pigment according to any one of claims 1 to 4, wherein the pigment has a particle size of 150 ml / 100 g and a particle size of 1 to 80 nm. 6. A carbon black having a particle size of 1 to 60 nm.
The pigment for paint according to any one of claims 1 to 5, which is: 7. The coating pigment according to claim 1, which has a powdering ratio of 40% or less. 8. The density of a molded product obtained by pressure molding is 2.58 times the bulk density of the raw carbon black.
8. The pigment for paint according to any one of items 1 to 7. 9. The paint pigment according to claim 1, wherein the shape of the molded product obtained by pressure molding is a column having a triangular or other polygonal cross section. 10. The paint pigment according to claim 9, wherein the shape of the molded product obtained by pressure molding is a cube or a rectangular parallelepiped. 11. A molded article obtained by pressure molding has a density of 0.
The paint pigment according to any one of claims 1 to 10, wherein the amount is 2 to 1.2 g / cc. 12. The paint pigment according to claim 11, which is obtained by using a slidable mold for pressure molding of carbon black. 13. A method for producing a paint, comprising using the pigment for a paint according to claim 1 as a pigment. 14. The method according to claim 13, wherein the paint is used as a back coat of a magnetic tape.