JPS60118754A - Pigment dispersion process and equipment therefor - Google Patents

Abstract

PURPOSE:To obtain a pigment capable of giving coatings with outstanding gloss and clearness, small color difference on color adjustment, etc., by primary dispersion of a formulation comprising pigment, resin and solvent followed by distilling off the solvent at reduced pressure then dispersion again while aging. CONSTITUTION:A formulation comprising pigment, resin and solvent is subjected to primary dispersion. The solvent in the resulting mixture is then either partly or fully distilled off under reduced pressure followed by redispersion of the product pref. at 60-120 deg.C while aging, thus accomplishing the objective dispersion of the pigment. Said redispersion while aging is preferably carried out in such a condition as to be <=100,000cps in the viscosity of said product (mixture).

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a pigment dispersion method used in the production of paints, inks, etc., and a pigment dispersion device used to carry out this method.

[Background technology]

Coating compositions containing pigments, such as paints and inks, are generally prepared by processing a formulation containing the pigment, resin face, solvent, and additives added as necessary using a pigment dispersion device such as a sand grinder mill, attritor, or ball mill. It is made by using and dispersing.

However, in order to satisfy the various performances required for paints, inks, etc., it is necessary to select materials, resins, and solvents from a wide range, so depending on the properties of the pigments and resins, When resins or pigments with poor wettability are used, performance such as image clarity and color separation during toning may be degraded.

Therefore, when performing pigment dispersion using the dispersion device mentioned above,
Attempts have been made to solve this problem by variously changing the proportions of pigments, resins and solvents used, and other manufacturing conditions, but no satisfactory results have yet been obtained.

(Purpose of the Invention) The present invention was made in view of the above circumstances, and provides a method for dispersing pigments that can obtain a coating composition with excellent separability, and a method for implementing this method for dispersing pigments. The purpose is to provide a pigment molecule l&device suitable for.

[Disclosure of the invention]

In order to achieve the above-mentioned object, the first invention firstly disperses a composition containing a pigment, a resin, and a solvent, and then distills off all or part of the solvent in the resulting mixture under reduced pressure. The gist of this is a method for dispersing an RN material, which is characterized in that the mixture is aged and redispersed, and the second part
The invention provides a container for containing a compound containing a pigment, a resin, and a solvent, a stirring means for stirring and dispersing the compound in the container, and a temperature in mM for adjusting the temperature of the compound in the container.
I means, vacuum generating means for reducing the pressure inside the container, and a condenser and receiver for cooling and recovering the solvent gradually decreasing from inside the container, and the container is loaded with a dispersion method. Its gist is a pigment dispersion device. Below, these two inventions will be described in detail.

The pigment dispersion method according to the first invention includes a step of firstly dispersing a composition containing a pigment, a resin, a solvent, and additives added as necessary, - adding a resin varnish as necessary after the first dispersion; Stir this evenly I')! The process includes a step of mixing, a step of distilling off the solvent in the mixture, and a step of aging the mixture and converting it into refraction 11.

Examples of devices for primarily dispersing the compound include a hatch-type rotating media disperser, a sand grinder, a ball mill,
Strike etc. are used. After the primary dispersion using these devices is completed, a portion of 4A1 fat varnish is added if necessary, and this is uniformly mixed with fflM'. In this case, although it varies depending on the type of pigment and the proportion of non-volatile content of the resin, approximately 5
It is preferable to add the resin varnish in a proportion of 0 to 150% by weight.

Next, part or all of the solvent in the mixture is distilled off under reduced pressure. Specifically, it is preferable that the nonvolatile content of the vehicle in the mixture is 60% or more. At this time, if the viscosity of the mixture becomes less than iHi and the fluidity becomes poor, it is preferable to heat the mixture to about 60 to 130°C and keep it warm within this temperature range. Preferably, the mixture is kept agitated during the distillation.

Once the distillation is complete, the mixture is stirred for about 20 minutes or more, preferably 30 to 120 minutes, to give 1! ! 1.Redisperse while forming. An example of a device for redispersing the mixture while forming it is a fly mixer. kneader,
Planetary mixers (vertical kneaders), twin-screw desilvers, hatch-type rotary media dispersers, etc. are used.
By using the pigment dispersion device according to the second invention, which will be explained later, the primary fraction a can be obtained without transferring the mixture.
This is most advantageous because redispersion and redispersion can be carried out continuously while ripening. The redispersion while forming y1 is preferably carried out at a temperature of 60 to 130°C. If the temperature is less than 60°C, the viscosity of the mixture will increase and the fluidity will deteriorate, so a sufficient 9-1 formation effect will not be obtained.If it exceeds 130°C, the resin or pigment in the mixture This is because there is a tendency to change the quality of the product and cause problems with product quality.
It is preferable that the viscosity of the mixture is 100,000 cP or less. This is because if it exceeds this range, the fluidity of the mixture tends to deteriorate, making it difficult to achieve a sufficient ripening effect.

Thereafter, if necessary, the recovered solvent and other necessary raw materials are added to the mixture and mixed uniformly to obtain a coating composition.

After dispersing the formulation, this coating composition is made by distilling off all or part of the solvent in the tq mixture to lower the melt ratio and increase the resin ratio. The adsorption of the resin to the pigment 6 is improved by removing the solvent adhering to the surface of the particles, and then the resin is aged by stirring, etc., so that the resin is sufficiently adsorbed to the pigment. It is thought that Therefore, gloss, sharpness,
Various performances such as color separation during color mixing are extremely excellent.

FIG. 1 shows a pigment dispersion device according to the second invention. This pigment dispersion apparatus is extremely suitable for carrying out the pigment dispersion method according to the first invention. As shown in the figure, for this pigment portion 11, the device is assembled with a container 1 whose lower part is narrower than the upper part and its lid 2, and the upward opening of the container 1 is sealed with the lid 2. It looks like this. The container 1 is for containing mixed raw materials 3, and a dispersion method 4 for applying impact force, grinding force, etc. to the raw materials 3 is placed inside the container 1, and on the lower outer periphery, A jacket 5 is provided as a temperature control means for heating and cooling the compounding material +4')tll 3 to control the temperature.

In addition, balls made of glass, steel, ceramic, zirconia, etc. are used. At the bottom of the container 1, there is provided an outlet 6 which does not allow the dispersion method 4 to pass through, but allows the processed material of the compounding raw material jjA material 3 to pass therethrough, and is equipped with a filtration means such as 11216a and a valve 6b. The lid 2 is provided with an inlet 2a for injecting the raw material 3 into the container 1, and a stirrer 7 as stirring means for stirring and dispersing the raw material 3 in the container 1. Inlet 2a can be opened and closed with the input L: I 2.
Instead of charging from a, a pipe may be connected to the lid 2, and the water may be charged from this pipe. The stirrer 7b has its driving means 7a mounted on the lid 2, and
The first stage 7a of the drive 7a is located at the bottom of the container 1. The tip 11.1 of the stirrer 7I has a disc-shaped stirring blade 7 removed therein.The drive means 7a is equipped with a transmission so that the number of turns can be changed It is preferable that it is equipped (1:!).
On the other hand: 1 yen is placed. This capacitor 8ε, J air inlet 1 inlet (a) and recovered solvent outlet I'l ll b are respectively ('IY, these are The entrances and exits are: I 1. i'!t! i"i'
9 and the pipe 101 are connected to the lid 2.
. The vacuum installed in the upper blade of 1st part 3)
Pipe suction 1111 (1)
The vacuum Bonzoro, 吋 continues. This vacuum bonno”
C11 volume)
;t, below it is set up a cold Jill Mizudai 1moku 1
The cooling water enters from d, and the cooling water comes out from the 1st side.
)1. 2l;-'-,). Below the 2nd Indenza 8, in the middle of the piping IC), there is a receiving tank (11) for solvent recovery.
Valves 12 and 13 are provided between the receiver 8 and the receiver tank 11 and between the receiver tank 11 and the lid 2, respectively.

An example of a case where a paint composition (rnn gold-containing resin composition) is prepared by carrying out the pigment dispersion method according to the first invention using the Gonokao O'-1 dispersion apparatus will be shown below. 1 liter of solvent, resin varnish and additives as necessary
iff or in a mixed state, it is charged into the container 1 through the input port 2a. In this case, it is preferable that the raw material 4A material is charged at the top such that the volume ratio of the volume of the raw material 4A to the total volume of the raw material 4 and the total volume of the raw material 1) in the container 1 is 1/2 to 2/1. Next, the input port 2a is closed and the driving means 7a is operated to 1'&,
By rotating the stirring blade 7C at high speed, the pigment is finely divided, and the pigment is dispersed uniformly and evenly into the mixture, thereby primary dispersing the mixture. 'y) tB! The time is usually 40 to 120 minutes, but it varies depending on the type of work.

After the dispersion is completed, a resin muff varnish is added if necessary, and the mixture obtained as described above or this mixture and the resin varnish are uniformly stirred and mixed by a stirrer 7 for 1 μm.

Next, stir 1'l' tJ! 7 is rotated at low speed, valve 12 is opened, and valve 13 is closed. Activate the vacuum pump to reduce the pressure in the container 1 to 30 to 100 ml (about H?) and flow cooling water into the condenser 8 (4). Then, if necessary, heat the mixture by passing steam or the like through Jackera 1-5 to distill off some or all of the solvent in the mixture. At this time, if the fluidity deteriorates, it is preferable to heat the mixture to about 60 to 130° C. by passing steam or the like through the jacket 5 and keep it warm within this temperature range. The solvent distilled under reduced pressure is condensed in a condenser 8 and transferred to a receiving tank 11.
to be collected.

When the distillation is completed, the vacuum pump is stopped and the inside of the container i is returned to an airtight pressure. Next, depending on the properties of the pigment, resin, etc., the 1u machine 7 is rotated at high or low speed.゛ζ
, by stirring the mixture in container 1! 71) to make the resin sufficiently adsorbed to the pigment and to prevent re-agglomeration to 11%. Thereafter, if necessary, the recovered solvent is returned to the container 1 by turning the valve 13 and mixed uniformly with the mixture remaining in the container 1 to obtain a paint composition. Then, this paint composition is taken out from the discharge port 6.

As mentioned above, the dispersion device according to the first invention is equipped with a container in which dispersion spheres are housed, a stirring means, a temperature adjustment means, a vacuum generation means, and a condenser, so that only one device is required. For example, the dispersion method according to the first invention can be carried out under the most favorable conditions.

In this way, if the dispersion method according to the first invention is carried out with one device, there will be no need to transfer the mixture for years, and the yield will also improve, so the productivity of the coating composition will be dramatically increased. improves. Additionally, compared to the case where several devices are used, the installation space is smaller and cleaning is easier.

The dispersion method according to the first invention is not necessarily carried out using one dispersion apparatus according to the second invention. Step of converting the blend into a first batch II&, distilling off the solvent in the mixture-1.
Alternatively, the steps of dispersing the mixture while ripening it may be carried out using separate apparatuses.

Next, examples and comparative examples of the pigment dispersion method according to the first invention will be described.

(Example 1) First, the composition shown in Table 1 was placed in the pigment portion 11 shown in FIG. Circumferential speed IU 10
The dispersion treatment was performed for 60 minutes by rotating at m/s.

Next, at minute 11, 88 parts by weight of alkyd resin varnish (60% nonvolatile content) was added to the mixture in the container, and then,
The temperature of the mixture was maintained at 80-85°C. Then, seal the container with a lid and pump the inside of the container with a vacuum pump.
The pressure was reduced to g. While rotating the stirring blade at a circumferential speed of 4 m/s, 83.5 parts by weight of the solvent in the mixture was distilled off, and the non-volatile content of the vehicle component in the mixture was reduced to about 80 parts by weight.
%. Then, the temperature of the mixture was maintained at 80 to 85°C, the viscosity of the mixture was set to 50,000 cP, and the stirring blade was rotated at a circumferential speed of 4 m/s and stirred for 30 minutes to perform redispersion while ripening. The mixture was then adjusted to the final paint formulation to obtain the paint.

(Example 2) A paint was prepared in the same manner as in Example 1, except that after the non-volatile content of the vehicle component in the mixture was adjusted to 93%, the viscosity of the mixture was adjusted to 120,000 cP and redispersed while aging. I made it.

(Comparative Example 1) For comparison, paint using the conventional method! l! I crushed it. first,
The formulations having the compositions shown in Table 1 were dispersed using a rotary media disperser, and after the dispersion was completed, the mixture was adjusted to the final coating formulation to obtain a coating material.

Gloss and toning special color separation properties (rubbing color difference) of the paint obtained in Example 1.2 and the paint obtained in Comparative Example 1
was evaluated. The results are shown in Table 2.

However, the color separation property was evaluated as follows.

-4゛, The black paint produced in the examples and comparative examples was mixed with q's white paint 1 in a ratio of 1:90, homogeneous and 7:I.
4: After 1 liter, dilute with diluting thinner to 15"/20℃ with 4 Ford cup (L7), then flow-coat the tin plate with the adjusted paint (I). 2. Dry to the touch 1. Immediately before rubbing a part of the painted surface strongly, I burnt it* to create a painted board. Rubbing color difference, 1. l of
(c) One color (the difference in ifj is determined by ΔE).

(1~゛ Margin) Table 2 From Table 2, the paints obtained in Example 1 and Example 2 were superior in gloss and color separation compared to the paint shown in Comparative Example 1. I know that there is.

(Example 3) First, a formulation having the composition shown in Table 3 was prepared in Example 1.
Dispersion processing was carried out under the same conditions as above.

(Margin below) Table 3 Next, 100 parts λ0 of acrylic resin varnish (non-volatile content 50%) was added to the mixture in the dispersion container, and then the solvent content in the mixture was reduced in the same manner as in Example 1. 90 parts by weight was distilled off to reduce the non-volatile content of the vehicle component in the mixture to about 80%.
And so. Then, ζ, the temperature of the mixture was maintained at 80 to 85°C, the viscosity of the mixture was set to 50,000 cl', and the stirring blade was rotated at a circumferential speed of 4 m/s -U°ζ30 '1111'! Aging and redispersion were performed by stirring. Then, adjust the mixture to the final paint formulation and apply the paint to f! 7.

(Example 4) A paint was prepared in the same manner as in Example 3, except that after the nonvolatile content of the vehicle component in the mixture was adjusted to 70%, the temperature of the mixture was maintained at 50°C and redispersed while aging. I made it.

(Example 5) A paint was prepared in the same manner as in Example 3, except that after the nonvolatile content of the vehicle component in the mixture was adjusted to 93%, the temperature of the mixture was maintained at 125°C and redispersed while aging. I made it.

(Comparative Example 2) For comparison, a paint was manufactured using a conventional method. First, the third
The formulations having the compositions shown in the table were dispersed using a rotary media disperser, and after the dispersion was completed, the mixture was adjusted to the final coating composition to obtain a coating material.

(Comparative Example 3) For comparison, a paint was produced in the following manner. first,
The formulations having the compositions shown in Table 3 were subjected to dispersion treatment under the same conditions as in Example 1. Next, the solvent in the mixture was distilled off to concentrate the mixture, so that the viscosity of the mixture was about 200,000 cP at room temperature. Then, the mixture was kneaded (kneaded) at room temperature using a roll mill. Thereafter, the mixture was turned into pellets, and the pellets were dissolved in a solvent to adjust the final coating composition to obtain the i'; i9 materials.

Examples 3-5. and the coating η'- obtained in Comparative Example 2.3.
The gloss and toning spot color separation (rubbing color difference) of No. 1 were evaluated. The results are shown in Table 4.

Table 4 From Table 4, the paints obtained in Examples 3 to 5 are the same as those in Comparative Example 2.
It can also be seen that the gloss and color separation properties are superior to those obtained in Comparative Example 3. The reason why the performance of the product obtained in Comparative Example 3 is inferior to that obtained in Examples 3 to 5 is thought to be that the mixture is insufficiently matured by kneading with a roll mill.

In order to investigate the effect of ripening by stirring, in Example 3, the mixture obtained by -order dispersion and this were stirred 11z Q
After adjusting the pH, the pigment particle size (unit: μ) of the mixture was measured by a light transmission centrifugal sedimentation method. The measurement results are shown in Table 5.

Table 5 Generally, it is considered that the smaller the average particle diameter of the pigment, the better the performance of the paint. Togoro is Example 3
As shown in Table 5, the paint of ゛, stirring 1! (? After aging, the performance is excellent as seen earlier even though the average particle diameter' is almost the same as after primary dispersion. This is because the performance of the paint, such as color separation, is This is thought to be because resin adsorption to the pigment surface has a greater influence than that based on the diameter.

(Example 6) Here, metal complex salt azo pigments (C, I) are used as pigments.

Vulva G, YIEI, LOW-129) were used. This pigment has a very fine primary particle size and has poor affinity with resins, so conventional methods have not been able to produce paints that provide sufficient performance such as transparency and gloss (especially 20° gloss). It was difficult to create.

First, a formulation having the composition shown in Table 6 was prepared in Example 1.
Dispersion processing was carried out under the same conditions as above.

(Margin below) Table 6 Next, 108 parts by weight of acrylic resin varnish (nonvolatile content 50%) was added to the mixture in the container, and the temperature of the mixture was kept at 80 to 85°C. Then, the container was sealed with a lid, and the pressure inside the container was reduced to about 401 Il 11111 g using a vacuum pump. The solvent in the mixture was distilled off while the IW stirring blade was rotated at a circumferential speed of 4 m/s, so that the nonvolatile content of the vehicle component in the mixture was about 80%. Then, ripening was carried out by rotating the stirring blade at a circumferential rotational speed of 4 m/s and stirring for about 40 minutes. 80-85℃ until ripening
The mixture was kept warm. After this, the mixture was adjusted to the final paint formulation to obtain Coat*1.

(Comparative Example 4) For comparison, a paint was manufactured using a conventional method. First, the 6th
The formulations having the compositions shown in the table were dispersed using a rotary media disperser, and after the dispersion was completed, the mixture was adjusted to the final coating composition to obtain a coating material.

The gloss and transparency (visual judgment) of the paint obtained in Example 6 and the coating Fl obtained in Comparative Example 4 were evaluated. 7th result
Shown in the table. However, in terms of transparency in the table, ◎ indicates good;
△ indicates slightly poor quality.

(Margin below) Table 7 From Table 7, it can be seen that the paint obtained in Example 6 is superior to that obtained in Comparative Example 4 in terms of gloss and transparency.

(Example 7) Ball mill, boiler and v as primary dispersion equipment
The paint was applied in the same manner as in Example 1, except that a butterfly mixer was used as a device for redispersing the paint.

The gloss and color toning characteristics of the paint obtained in Example 7 were evaluated. The results are shown in Table 8.

From Table 8 Table 2 and Table 8, the paint obtained in Example 7 was:
When compared with the paint obtained in Example I, it can be seen that the gloss and color separation properties are almost the same.

〔Effect of the invention〕

The pigment dispersion method according to the first invention involves first dispersing a composition containing a pigment, a resin, and a solvent, and then distilling off all or part of the solvent in the iN mixture under reduced pressure.
Next, since this mixture is aged and redispersed, a coating composition with excellent performance can be obtained. The pigment dispersion device according to the second invention includes a container for containing a compound containing a pigment, a resin, and a solvent, a stirring means for stirring and dispersing the compound in the container, and a container for dispersing the compound in the container. a temperature adjusting means for adjusting the temperature of the container, a vacuum generating means for reducing the pressure in the container, and a condenser and a receiver for cooling and collecting the solvent gradually decreasing from the container,
Since the container is loaded with a dispersion method, it is extremely suitable for carrying out the pigment dispersion method according to the first invention.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of one embodiment of a pigment dispersion device according to the second invention. 1... Container 4... Dispersion method 5... Jacket
7...Agitator 8...Condenser 11...Receiving tank agent Patent attorney Takehiko Matsumoto

Claims (5)

[Claims] (1) After primary dispersion of a mixture containing pigment, resin, and solvent, all or part of the solvent in the resulting mixture is distilled off under reduced pressure conditions, and then this mixture is aged and redispersed. A pigment dispersion method characterized by: (2) Redispersion while aging is possible at a temperature of 60 to 120
The pigment dispersion method according to claim 1, which is carried out at a temperature of .degree. (3) Re-dispersion during aging reduces the viscosity of the mixture to 1
The pigment dispersion method according to claim 1 or 2, which is carried out under conditions of 00,000 cP or less. (4) The pigment dispersion method according to any one of claims 1 to 3, wherein the redispersion while aging is performed under stirring. (5) Pigment dispersion method according to any one of claims 1 to 4, in which the steps from the second dispersion to the redispersion while ripening are carried out continuously in the same container (6) Pigment, resin and a container for accommodating a compound containing a solvent, a stirring means for stirring and dispersing the compound in the container, a temperature adjusting means for adjusting the temperature of the compound in the container, and a device for reducing the pressure in the container. 1. A pigment dispersion device comprising a vacuum generating means, a capacitor and a receiver for cooling and recovering the solvent distilled from the container, and a dispersion method is loaded in the container.