JPH0445176A - Manufacturing method of carbon black paint - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for producing carbon black paint used for black coloring, conductive paint, back coat paint for magnetic recording media, and the like.

Conventional technology Conventionally, ball mills and sand mills have been used to disperse carbon black and produce paints. The kneading process (above) is always necessary, and a planetary mixer, kneader 1 pressure kneader, continuous kneader 1 twin-screw kneading extruder, etc. are used as coating equipment.

Invention or problem to be solved In order to obtain a highly dispersed coating as mentioned above, a kneading process with high viscosity is essential.In this kneading process, the dispersion becomes extremely high temperature, so It is necessary to consider the decomposition of commonly used nitrified cotton and polyvinyl chloride. When these are thermally decomposed, denitrification and dehydrochlorination are generated, making the paint acidic and causing corrosion of the disperser and the metal being coated, so the problem is that only binder resins with good thermal stability can be used. there were. Furthermore, these clay-like kneaded materials have a viscosity (2
The problem was that the dilution process from 0 to 150 poise was extremely difficult and time consuming.

In addition, other methods of dispersing with high shear force include dispersion and coating using a three-roll mill or two-roll mill, but these also cause the dispersion to reach a very high temperature and cause the coating to dry during dispersion and coating. Therefore, nitrified cotton, which is good for dispersing carbon black (in a dry state, has self-igniting properties due to impact) cannot be used alone as a binder resin, and it was also necessary to consider the thermal decomposition of the binder resin. . These problems adversely affect not only product quality but also manufacturing costs.

The present invention solves the above-mentioned problems, and provides a carbon black coating in which highly dispersed carbon black is made into a coating in a simple manufacturing process and in a short time, resulting in a carbon black coating with stable quality and low manufacturing cost. The purpose of this invention is to provide a method for manufacturing paint.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention has conducted various studies and found that a wetting process as a pre-dispersion/coating process is very effective for dispersing carbon black. .

The fL wet process is a process in which only a carbon blank and a solvent are mixed, and the surface of the carbon black particles is thoroughly wetted with the solvent, and the binder resin is applied to the surface of the carbon black particles by pushing out air and other gases that adhere to the surface. It facilitates adsorption and improves dispersibility. The equipment used for this wetting process includes a planetary mixer, and it is not easy to remove the paint from it.

When a ball mill, which is a feature of the present invention, is used in the wetting process, the wetting effect is good, pre-mixing with the binder resin is possible in the ball mill, and it is easy to take out, making it suitable for use in a sand mill for the next dispersion process. It can be taken out directly to the tank and can be quickly transferred to the dispersion process. Furthermore, when a sand mill is used, the time required for the dispersion process can be significantly shortened compared to when a ball mill is used.

Although this method is very simple, it has not been used until now, because when using a sand mill in the dispersion process, the viscosity of the dispersion coating must be 20 poise or higher, otherwise the dispersion medium (such as glass beads) may wear out or crack. Because of this, the viscosity of the premixed paint must be 20 voids or more because it is undesirable because it mixes with the paint. When premixing is performed using a ball mill, paints with 20 or more voids cannot be efficiently removed from the ball mill, and most of the paint remains inside the ball mill. Even if you use a pump to suck it up, you can only get out about 60% of the contents.

However, as a result of the study, after the wetting process with solvent and carbon black, when a binder resin was added and the ball mill was operated, the viscosity of the wet material, which was slurry-like, decreased rapidly after just a few rotations, and if the operation continued, the viscosity of the wet material decreased from 2. It was found that the viscosity rose rapidly again after 3 minutes. Therefore, if the ball mill is operated for less than one minute after adding the binder resin and the paint is taken out when the paint viscosity is at its lowest, most of the paint inside the ball mill can be taken out.

Function: By configuring the method for producing a carbon black paint of the present invention from a wetting process using a ball mill, a premixing process, and a dispersion process using a sand mill, a highly dispersed carbon black paint can be produced using a simple manufacturing process. Provides a carbon black paint that can be obtained in a short time, has stable quality, and has low manufacturing costs.

Example The present invention will be specifically explained below with reference to Examples.

(Example 1) In order to find out the effect of the wetting process, a carbon black paint B which was subjected to the 6L wetting process and a carbon blank paint B which was not subjected to the 6L wetting process were prepared using only a ball mill.

(Carbon black paint A) Paint manufacturing method Wetting process: Steel ball mill Dispersion process: The following carbon black and organic solvent were put into a steel ball mill with an internal volume of 100 liters, and the carbon black was operated at 40 rpm for 5 hours to wet the carbon black. Go two.

Carbon black 5.0 kg (manufactured by Mitsubishi Kasei Corporation, trade name MA-7B) Organic solvent cyclohexanone 6.5 kg Methyl ethyl ketone 4.5 kg Then, as a binder resin, nitrocellulose solution 4.5 kg (manufactured by Asahi Kasei Corporation, trade name BTH1) /16 methyl ethyl ketone solution, solid content 25% by weight) was added, and 40
The mixture was operated and dispersed at rpm for 25 hours to obtain a carbon black paint.

(Carbon black paint B) Paint manufacturing method Wetting process; None Dispersion process; Steel ball mill As a manufacturing method for carbon black paint that omit the wetting process, the same ball mill as that used for carbon black paint was used to produce the same composition, but the following materials were used. The mixture was charged into a ball mill at once and operated and dispersed at 40 rpm for 30 hours to obtain carbon blank paint B.

Carbon black 5. Okg (manufactured by Mitsubishi Kasei Industries ■, product name MA-7B) Organic solvent cyclohexanone 6.5 kg Methyl ethyl ketone 4.5 kg Binder resin nitrocellulose solution 4.5 kg (manufactured by Asahi Kasei Industries ■, product name BTHI/+6 methyl ethyl ketone solution, solid content 25% by weight) In order to observe the carbon black dispersion state of the above two types of carbon black paints A and B, the force inside the ball mill, -
The bomb black paint was taken and applied onto a polyethylene terephthalate film using an applicator with a gap of 25 μm, and the #! Limb gloss was measured.

The results of carbon black paint and carbon black paint B are compared and shown in FIG.

As is clear from these comparisons, the gloss of the carbon black paint subjected to the wet process increases quickly, and the final gloss is also higher than that of carbon black paint B.

From the above, it can be seen that the wetting process using a ball mill is very effective.

However, if a sand mill is used in the dispersion process, a carbon black paint with a higher degree of dispersion can be obtained.

(Example 2) Two types of carbon blank paints were prepared using a sand mill in the dispersion process.

(Carbon black paint C) Paint manufacturing method 6L milling process: Steel ball mill premixing process: Steel ball mill dispersion process; Sand mill The following carbon black and organic solvent were charged into a steel ball mill with an internal volume of 100 liters, the same as in Example 1, and
RPM for 5 hours and a 6L drop of carbon black was applied to the carbon black paint of Example 1 in the same manner.

Carbon black 10.0 kg (manufactured by Mitsubishi Kasei Corporation, trade name MA-7B) Organic solvent cyclohexanone 13.0 kg Methyl ethyl ketone 9.0 kg After that, nitrocellulose solution as binder resin 9.0 kg (7I! Kasei Kogyo@J!2 Product name BTH1/+6
Methyl ethyl ketone solution, solid content 25wt 11”6
') was added and operated at 40 rpm for 1 minute to premix the carbon black and binder resin. Thereafter, the paint was taken out from the ball mill and dispersed using the sand mill equipment and conditions described below to obtain carbon blank paint C.

Sand mill: ■Super mill capacity 10 manufactured by Bengami Seisakusho
Liter disk circumferential speed 12 m/sec Paint flow rate: 1 liter/min Number of dispersion passes: 6 passes (carbon black paint D) Paint manufacturing method Pre-mixing process: Daysilver dispersion process: Sand mill Put the following paint materials into the tank and use Daysilver. After mixing for 2 hours, the mixture was dispersed using a sand mill in the same manner as carbon black paint C to obtain a carbon black paint.

Carbon black IO, Okg (manufactured by Mitsubishi Kasei Corporation, trade name LiA-7B) Organic solvent cyclohexanone 13.0 kg Methyl ethyl ketone 9.0 kg Binder resin nitrocellulose solution 9.0 kg (manufactured by Asahi Kasei Corporation - trade name BTH1/16) (Methyl ethyl ketone solution, solid content 25% by weight) In order to observe the carbon black dispersion state of the carbon black paints C and D, samples of the paint were collected after each dispersion pass, and the paints were applied onto a polyethylene terephthalate film using an applicator in the same manner as in Example 1. The gloss of the coating film was measured.

A comparison of the dispersion results of carbon black paints C and D is shown in FIG.

As is clear from these comparisons, the wetting effect by the ball mill was good, the gloss at the 6th pass was about 20% higher, and a highly dispersed carbon black paint was obtained.

In addition, in the case of carbon black paint C, the yield of paint when taken out naturally from the ball mill after the premixing process is 9
It was as high as 896, and I was able to remove most of the carbon black paint inside the ball mill.

Furthermore, in Figures 1 and 2, when comparing the dispersion process using a ball mill (carbon black paint A) and a sand mill (carbon black paint C), the final gloss level is approximately 15% higher with the sand mill, and the dispersion time is also approximately The time was as short as 5 hours (approximately 50 minutes per sand mill bath), and the time required for dispersion using a ball mill could be reduced to about 115 hours.

Effects of the Invention As described above, according to the carbon black production method of the present invention, carbon black can be made into a paint in a highly dispersed state in a short time with a simple production process, and the quality is stable and production cost is improved. It is possible to provide a carbon black paint with low carbon black, and its practical value is great.

[Brief explanation of the drawing]

FIG. 1 is a characteristic diagram of ball mill operation/dispersion time versus glossiness for carbon black paints A and B, and FIG. 2 is a characteristic diagram of glossiness versus number of sand mill dispersion passes for carbon black paints C and D. Carbon black paint A: A material manufactured by having a wetting process and dispersing process performed in a steel ball mill. Carbon black paint B... Manufactured by having no wetting process and performing a dispersion process in a steel ball mill. Paint, Carbon black paint C... A paint that has a wetting process and is manufactured by performing a dispersion process in a sand mill, Carbon black paint D... A paint that does not have a wetting process and is manufactured by performing a dispersion process in a sand mill. . Agent Yoshihiro Morimoto Figure 87

Claims (1)

[Claims] 1. A production method of dispersing carbon black using a binder resin and making it into a paint, which includes a wetting step of mixing carbon black and a solvent using a ball mill, and a wetting step of mixing carbon black with the solvent using the ball mill. A method for producing a carbon black paint comprising a premixing step of premixing carbon black and a binder resin, and a dispersion step of dispersing the carbon black premixed with the binder resin using a sand mill.