JPH04339877A - Manufacture of coloring agent - Google Patents

Abstract

PURPOSE:To easily obtain a coloring agent which is excellent in pigment dispersion and of which the maximum particle diameter of coarse pigment particles can readily be reduced to 30mum or smaller when used for coloring, e.g., thermoplastic resin, with improved productivity without the necessity for subsequent heating and kneading with three rolls, etc., hitherto required. CONSTITUTION:Manufacture of a coloring agent, in which a pigment, for example, wet cake of phthalocyanine pigment or powder carbon black and a wax dispersion prepared by dispersing a wax, for example, polyethylene wax in a dispersion medium comprising, e.g., water or a hydorphilic solvent are heated and kneaded to effect phase substitution (flushing), separated liquid material such as a dispersion medium is removed, and preferably further heating and kneading is performed while removing remaining liquid material; and manufacture of a coloring agent, in which the obtained coloring agent and a thermoplastic resin are heated and kneaded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a colorant. In detail, a coloring agent is obtained by heating and kneading a pigment and a wax dispersion, and the coloring agent has good pigment dispersion and the coarse particle size of the pigment is 30 μm or less when coloring thermoplastic resin etc. The present invention relates to a method by which this can be easily obtained with good productivity.

0002

[Prior art] As a method for producing colorants for thermoplastic resins,
Broadly speaking, they are as follows: ■ A method in which powdered pigment and powdered wax are premixed, mixed and kneaded using a heating kneader, etc., then kneaded two or more times using three rolls, etc., cooled, and then crushed. ■ Pigment wet cake and powdered wax There is a method in which the mixture is mixed and kneaded in a heating kneader, the separated water is removed, and the mixture is further heated and kneaded in a heating kneader while removing residual water, and after cooling, the mixture is crushed.

0003

[Problem to be solved by the invention] However, the above ■
The coloring agents obtained by methods (1) and (2) do not have good compatibility between the pigment and wax, resulting in insufficient pigment dispersion, and when used for coloring resin, coarse pigment particles easily form up to 30
There is a problem in that it is difficult to obtain a colorant with excellent pigment dispersibility that is less than .mu.m. Therefore, conventionally, in order to obtain a colorant with good pigment dispersion, it is necessary to further heat kneading two or more times using three rolls or the like, which poses a problem of poor productivity.

0004

[Means for Solving the Problems] As a result of intensive research in view of the above situation, the present inventor has developed a method of phase replacement (flushing) by heating and kneading a pigment and a wax dispersed in a dispersion medium.
If a powdered pigment is used as the pigment, the dispersion medium is removed, and if a pigment slurry or a pigment wet cake is used as the pigment, the water and dispersion medium are removed, and preferably the remaining water etc. When heated and kneaded while removing, these are mixed together in fine particles, so a colorant with good pigment dispersion can be easily obtained, and the subsequent heating and kneading with three rolls, etc., which was previously required, is no longer necessary. becoming unnecessary,
It was discovered that the colorant obtained here can be suitably used as a color base in the production of colorants such as masterbatches in which pigments are dispersed at high concentrations in resin, and that the production of masterbatches etc. is facilitated. The invention was completed.

That is, the present invention provides a method for producing a colorant, which is characterized by heating and kneading a pigment and a wax dispersion to cause phase replacement, and removing the separated liquid, and the colored product obtained thereby. The present invention provides a method for producing a coloring agent, which comprises heating and kneading a coloring agent and a thermoplastic resin.

Pigments used in the present invention include powder pigments and aqueous pigments. Here, as water-based pigments,
For example, slurry obtained in the pigment production process before the drying process (
Examples include liquid) and wet cake (paste) pigments. Among these, wet cake is most preferred because it is easy to handle and a colorant with good pigment dispersion can be easily obtained.

[0007] Types of the pigments include organic pigments, inorganic pigments, extender pigments, and metal powders, among which organic pigments and inorganic pigments are preferred. Examples of organic pigments include azo pigments such as azo lake, insoluble azo, and condensed azo; phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green; threnic pigments such as anthraquinone, perinone, and perylene; and quinacridone, isoindolinone, and dioxazine. Examples include fused polycyclic pigments. Inorganic pigments include, for example, titanium pigments such as titanium oxide and titanium yellow; iron oxide pigments such as Bengara and yellow iron oxide; chromate pigments such as yellow lead and chrome vermilion; aluminic acids such as cobalt blue. Examples include salt pigments and carbon black. Examples of extender pigments include calcium carbonate, aluminum silicate, silica sand, calcium hydroxide, talc, clay, and mica. Furthermore, examples of the metal powder include brass powder, aluminum powder, and the like.

The wax used in the present invention is not particularly limited, and any wax that has conventionally been used as a dispersant for pigments, such as colorants, etc. can be used, such as low molecular weight polyolefin waxes such as polyethylene and polypropylene. , montan acid wax and its esters,
Examples include carbana wax and its esters, among which polyolefin waxes are preferred. Incidentally, as these waxes, powdered waxes are usually used. Among them, the average particle diameter is 500 μm or less, especially 50 μm.
The following powdered waxes are preferred.

[0009] The above-mentioned polyolefin waxes include those having an average molecular weight of 700 to 20,000, preferably 900 to 10,000, and modified polyolefins obtained by modifying them with styrene, unsaturated fatty acids, vinyl acetate, acrylic acid, etc. Preferred examples include wax, and polyethylene wax is particularly preferred.

The wax dispersion used in the present invention is as follows:
For example, wax may be dispersed in a dispersion medium such as water or a hydrophilic solvent such as methanol or ethyl cellosolve using a mixer, a dispersion stirrer, or the like. The average particle diameter of the dispersed wax is usually 500 μm or less, preferably 50 μm or less. Further, the amount of wax to be dispersed is usually 0 to 100 parts by weight of the dispersion medium.
．． It ranges from 1 to 200 parts by weight, preferably from 10 to 100 parts by weight. In addition, as a dispersion stabilizer, polyoxyethylene nonylphenol ether (preferably HLB12
It is also possible to add the following), naphthalene sulfonic acid formalin condensate, etc., but if it is made into a colored molded product, it will migrate to the surface and cause the surface to become dirty.
It is preferable to use 0.2 parts or less per part.

Furthermore, in addition to the above-mentioned method, the wax dispersion is stabilized in water or a hydrophilic solvent by introducing hydrophilic groups such as hydroxyl groups, carboxyl groups, their ammonium salts, and other alkali salts into the wax. The use of dispersions is also possible.

[0012] In order to obtain a colorant by the production method of the present invention, for example, a wax dispersion, a pigment, and, if necessary, additives such as a lubricant and a stabilizer, other waxes, a hydrophobic solvent, etc. are mixed together. above the melting temperature of the wax, e.g. 90℃
After mixing and kneading at ~140° C., performing phase exchange (flushing), and removing separated liquid substances such as water and other dispersion media, the mixture is further heated and kneaded, preferably while dehydrating under reduced pressure. After cooling the minced meat, it may be pelletized or powdered. Note that the rate of separation of water and hydrophilic solvents differs depending on the type of pigment, and the rate of separation is faster for pigments with higher lipophilicity.

[0013] Examples of the kneading machine used here include discontinuous kneading machines such as kneaders and Banbury mixers, and continuous kneading machines such as single-screw or multi-screw extruders equipped with dehydration holes.

[0014] The proportion of the wax dispersion and pigment to be used varies greatly depending on the type of pigment, purpose of use of the colorant, application, etc., and is not particularly limited, but is usually 1 to 2,000 parts by weight per 100 parts by weight of pure wax. Parts, preferably 40 to 200 parts by weight for organic pigments and 100 to 500 parts by weight for other pigments.

The coloring agent of the present invention thus obtained is:
For example, if it is in the form of pellets, it can be used as it is as a masterbatch, but by combining several kinds of these as a color base, toning the color, and heating and kneading it with a diluted resin such as a thermoplastic resin, it is easy to create a masterbatch. It is also possible to obtain toned colorants.

[0016]

[Examples] The present invention will be specifically explained below with reference to Examples and Comparative Examples, but the present invention is not limited thereto in any way. Note that parts and percentages in the examples are based on weight.

Example 1 Powdered polyethylene wax (average molecular weight 3,500,
Add 130 parts of water and 20 parts of isopropyl alcohol to 100 parts (average particle size 200 μm), and disperse with a dispersion stirrer for 30 minutes.The resulting wax aqueous dispersion is placed in a 1000 liter kneader, and then a phthalocyanine green wet cake (pigment Add 250 parts (40%) to 120
The mixture was mixed and kneaded at ℃ for about 2 hours until water and isopropyl alcohol were separated. After tilting the kneader at 90 degrees to remove the separation and dispersion medium, the mixture was further kneaded for 1 hour while being dehydrated under reduced pressure, and after cooling, it was crushed using a rotary cutter type crusher to obtain a powdered colorant (1).

After mixing 50 parts of the obtained colorant (1) and 50 parts of low density polyethylene (density 0.92 g/cc, melt index 3 g/10 min.) in a tumbler, the mixture was heated to 140° C. with a screw diameter of 40 m. /m, and kneaded in a single-screw extruder with a screw rotation speed of 150 rpm.
A pellet-like masterbatch (1) was obtained.

After mixing 4 parts of this masterbatch (1) and 96 parts of low density polyethylene in a tumbler,
The dough was kneaded for 5 minutes using two rolls with a diameter of 6 inches heated at I asked for. The results are shown in Table 2. (Measurement of area index and maximum particle size) A sample of about 1 mg was cut from the obtained sheet, placed on a slide glass, and a cover glass was placed on top.The sample was then heated and pressed at 230°C to a thickness of 15 to 20 μm. After forming into a film, 10
Select the field of view with the worst dispersion using a 0x optical microscope, determine the particle size and number of particles with a particle size of 11 μm or more in this field of view, and calculate the representative area for each number of particles that fall within the particle size range shown in Table 1 below. The values were multiplied by the index and then summed. This was done for five samples, and the average of the sums was taken as the area index of the colorant. Moreover, the diameter of the largest particle observed in the five samples mentioned above was defined as the maximum particle diameter. Note that particles with a particle size of 10 μm or less were excluded.

[0020]

Example 2 Powdered polyethylene wax (average molecular weight 3,000,
The procedure was the same as in Example 1, except that 150 parts of water and 0.2 parts of polyoxyethylene propylene block polymer were added to 100 parts (average particle size 20 μm) of the wax, and an aqueous wax dispersion obtained by dispersing with a dispersion stirrer for 30 minutes was used. Powdered colorant (
2) and a pelleted masterbatch (2) were obtained. Next, a green sheet with a thickness of 1 mm was obtained using the masterbatch (2) in the same manner, and the area index and maximum particle size were determined in the same manner. The results are shown in Table 2.

Example 3 A styrene-grafted polyethylene wax modified with ammonium carboxylate salt (molecular weight 1.80) was used as a wax dispersion.
0, average particle size 15 μm) water dispersion (wax content 40
Powdered colorant (3) was prepared in the same manner as in Example 1, except that 250 parts of dispersed wax (average particle size of dispersed wax of 10 μm or less) were used.
And a pelleted masterbatch (3) was obtained. Then, in the same manner, a thickness of 1 mm was obtained using the masterbatch (3).
A green sheet was obtained, and the area index and maximum particle size were determined in the same manner. The results are shown in Table 2.

Example 4 As a wax dispersion, an aqueous dispersion (wax content 40%, dispersed wax average particle diameter 10 μm or less) of an aqueous dispersion of polyethylene wax modified with carboxylic acid ammonium salt (molecular weight 4,000, average particle size 5 μm) 300 A powdered colorant (4) and a pelleted masterbatch (4) were obtained in the same manner as in Example 1 except that 80 parts of powdered carbon black was used as the pigment. Next, a black sheet with a thickness of 1 mm was obtained using the masterbatch (4) in the same manner, and the area index and maximum particle size were determined in the same manner. The results are shown in Table 2.

Example 5 300 parts of the aqueous dispersion of carboxylic acid ammonium salt modified polyethylene wax used in Example 3 and 80 parts of powdered carbon black were mixed in an 800 liter Henschel mixer, and the resulting mixture was mixed with a screw. Diameter 65m
/m, screw rotation speed 250 rpm, temperature 120 ° C. Heat kneading was carried out while removing separated water using a twin-screw extruder with dehydration holes to obtain pellet-like colorant (5), except that Example 1 was used. A pelleted masterbatch (5) was obtained in the same manner as above. Next, a black sheet with a thickness of 1 mm was obtained using the masterbatch (5) in the same manner, and the area index and maximum particle size were determined in the same manner. The results are shown in Table 2.

Comparative Example 1 Powdered colorant (1') and pelleted master were prepared in the same manner as in Example 1, except that 100 parts of powdered polyethylene wax was used instead of the polyethylene wax aqueous dispersion obtained in Example 1. Batch (1') was obtained. Next, a green sheet with a thickness of 1 mm was obtained using the masterbatch (1') in the same manner, and the area index and maximum particle size were determined in the same manner. The results are shown in Table 2.

Comparative Example 2 100 parts of powdered polyethylene wax and 100 parts of powdered phthalocyanine green were placed in an 800 liter pressure kneader, mixed for 10 minutes, heated at 120°C for 20 minutes, and then cooled and kneaded for 15 minutes. The mixture was ground, passed twice through three rolls with a diameter of 16 inches heated to 120° C., and then pulverized with a rotary cutter type pulverizer to obtain a powdered colorant (3'). Next, a pellet-like masterbatch (3') and a green sheet with a thickness of 1 mm were obtained in the same manner as in Example 1 except that this colorant (3') was used, and the area index and maximum particle size were determined in the same manner. Ta. Table 2 shows the results.
Shown below.

[0027]

[0028]

[Effects of the Invention] According to the production method of the present invention, a coloring agent with excellent pigment dispersibility that easily has a coarse pigment particle size of 30 μm or less when used for coloring thermoplastic resins, etc. can be easily obtained, and the subsequent heating kneading using three rolls or the like, which was conventionally necessary, is no longer necessary, and productivity is improved. Furthermore, the colorant obtained here can be suitably used as a color base in the production of a colorant such as a masterbatch in which a pigment is dispersed in a resin at a high concentration, and the production of the colorant is facilitated.

Claims (5)

[Claims] 1. A method for producing a colorant, which comprises heating and kneading a pigment and a wax dispersion to cause phase replacement, and removing the separated liquid. 2. The manufacturing method according to claim 1, wherein a polyolefin wax dispersion is used as the wax dispersion. 3. The manufacturing method according to claim 1, wherein a wet cake of pigment is used as the pigment. 4. The manufacturing method according to claim 1, wherein after removing the liquid material, further heating and kneading is performed. 5. A method for producing a colorant, which comprises heating and kneading the colorant obtained according to claim 1, 2, 3, or 4 and a thermoplastic resin.