JPH10279877A - Method for producing pigment composition for coloring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coloring pigment composition in which the presence of coarse particles of a pigment is not recognized, fine particles are homogeneously dispersed, and excellent in coloring property, sharpness and transparency. SOLUTION: A pigment press cake, an antioxidant and a melting point of 80 ° C to 11 ° C are added to a thermoplastic resin having a melting point of 100 ° C to 130 ° C.
A pigment is transferred into the resin by adding a dispersant at 0 ° C. and kneading to a temperature equal to or higher than the melting point of the thermoplastic resin to remove the separated water. Provided is a method for producing a pigment composition for coloring, which comprises kneading the composition and having excellent dispersibility of pigment particles.

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 pigment composition for coloring, and more particularly to a method for producing a pigment composition having excellent pigment dispersibility.

[0002]

2. Description of the Related Art Conventionally, a pigment resin composition for coloring, for example,
Examples of the pigment resin composition for plastic coloring include, for example, dry color, which is a powdery colorant obtained by mixing a pigment with a dispersant such as metal soap, and a masterbatch in which the pigment is dispersed at a high concentration in the resin. Widely used.

[0003] These coloring pigment compositions are produced by melt-kneading a pigment powder and a dispersant or a carrier resin using a roll or a kneader. However, when pigment powder is used, once the pigment powder is dried, the pigment particles are aggregated and coarsened, so that it is extremely difficult to redisperse these particles. As a result, the dispersibility of the pigment decreases, and the colorant However, there is a drawback that clarity, transparency and the like are lacking.

On the other hand, there has been proposed a method in which an organic medium, for example, a binder, is added to a pigment aqueous cake in which little aggregation occurs in a wet state, and the mixture is kneaded to flush (phase invert) pigment particles from an aqueous phase to an organic phase. However, during the flashing (phase inversion) of pigment particles, if strong kneading is performed for a long time under a heating state, the pigment component and the synthetic resin component are deteriorated, and the coloring properties, transparency, vividness, etc. of the colorant are reduced. The present inventors have grasped the phenomenon that is decreased.

In order for the colorant to be used not only for plastics such as fibers, films or molded products, but also for recording of copier toners, solvent inks, etc., it is required that the colorants have particularly excellent clarity and transparency. There is an urgent need to develop a method for producing a pigment composition for coloring in which the pigment is finely dispersed at a high concentration and is more stable.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a pigment having a high concentration and a fine pigment by using a pigment press cake and a thermoplastic resin in view of the technical development of the colorant as described above. It is an object of the present invention to provide a method for producing a pigment composition for coloring in which pigment particles are highly dispersed and which have excellent coloring stability.

[0007]

Means for Solving the Problems Accordingly, the present inventors have:
As a result of intensive studies to solve the above-mentioned problems, the thermoplastic resin and the pigment presscake have an antioxidant and a melting point of 80 ° C.
By adding and kneading a dispersant at ~ 110 ° C, a predetermined amount of the pigment presscake is further divided and sequentially added and heated and kneaded, and heat kneading is performed in at least two steps under different processing conditions. As a result, the present inventors have found that the above-mentioned objects of the present invention can be achieved, and have completed the present invention based on these findings.

[0008] That is, the present invention provides a method for producing a composition having a melting point of 100 ° C to 13
A pigment press cake having a pigment content of 15% by weight to 80% by weight, an antioxidant and a melting point of 80 ° C.
By adding a dispersion of 110 ° C., gradually heating the thermoplastic resin and finally kneading at a temperature equal to or higher than its melting point, the pigment is transferred into the thermoplastic resin, and separated water is removed. The present invention relates to a method for producing a pigment composition for coloring, which is characterized by heating and kneading later.

Further, as a preferred embodiment of the present invention, a thermoplastic resin having a melting point of 100.degree. C. to 130.degree. C., an antioxidant and a dispersant having a melting point of 80.degree.
Dividing the added amount of the pigment press cake of from 80% by weight to 80% by weight, adding the divided amount, kneading at each addition at a temperature equal to or higher than the melting point of the thermoplastic resin, and transferring the pigment into the thermoplastic resin. A pigment-containing resin phase; removing the separated water; heating the pigment-containing resin phase to 100 ° C. or higher, removing water by evaporation, and then kneading, so that a pigment composition for coloring is included. Can be provided.

The specificity of the present invention is that the melting point is 100 ° C. to 130 ° C.
The antioxidant and the dispersant having a melting point of 80 ° C. to 110 ° C. coexist in the step of flashing the pigment into the resin phase, which comprises kneading the thermoplastic resin and the pigment press cake at a temperature of at least the melting point of the thermoplastic resin. It has been found that this makes it possible to maintain the coloring property, clarity, transparency and stability of the coloring pigment composition.
The specificity of the present invention resides in the fact that the pigment press cake is added to a thermoplastic resin in a predetermined amount in a divided manner, and the effect is obtained by flushing the pigment each time. Further, a pigment composition for coloring excellent in dispersibility is obtained by combining a step of flushing a pigment by heating and kneading a thermoplastic resin and a pigment press cake and a step of kneading a pigment-containing resin phase at a temperature equal to or higher than the temperature of the flushing step. In finding things that can be obtained.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The thermoplastic resin used in the method for producing a coloring pigment composition of the present invention is a water-insoluble resin which is solid at ordinary temperature, and resins which are conventionally used as a pigment dispersant,
Resins and the like used as carrier resins for masterbatches can be mentioned. As typical examples, polyvinyl chloride, ethylene monoacetate copolymer, polyethylene, polypropylene, polystyrene, acrylic polyamide, polycarbonate, saturated polyester, polyacetal,
Examples thereof include polyphenylene oxide, polyphenylene sulfide, polyarylate, polyallyl sulfone, fluororesin, liquid crystal polymer, and polystyrene-based, polyolefin-based, and polyurethane-based thermoplastic elastomers. Although the molecular weight of these resins is not particularly limited, the weight average molecular weight is 1500 to 8
0000 is preferred from the viewpoint of colorability.

According to the present invention, among the above thermoplastic resins, those having a melting point of 100 ° C. to 130 ° C. are selected and used. Particularly preferred thermoplastic resins are polyethylene, polypropylene and ethylene-vinyl acetate copolymer.
Here, the melting point of the resin is DSC ASTM D-341.
This was measured by the method of Example 8.

The pigment press cake used in the method for producing the coloring pigment composition of the present invention has a pigment content of 15% by weight or less.
It is an aqueous wet cake of 80% by weight, preferably 20% to 70% by weight, and is a water-containing aqueous pigment suspension obtained at the time of pigment production. Since such a pigment press cake does not go through a drying step at the time of production, the pigment press cake is present in a state of primary particles without aggregation of pigment particles, and hardly contains particles of 30 μm or more. Pigment content 15
If the amount is less than 20% by weight, a large amount of a pigment press cake is required to obtain a pigment composition for coloring at a high concentration, and the operation becomes complicated, and the process is uneconomical. However, it is not preferable because secondary aggregated particles may be generated.

As the pigment, any of an organic pigment and an inorganic pigment can be used. For example, organic pigments include azo lake, hanza, benzimidazolone, diallylide, pyrazolone, yellow, and red azo pigments, phthalocyanine, quinacridone, perylene, perinone, dioxazine, and anthracene. Examples include quinone-based, isoindolinone-based polycyclic pigments and aniline black, and the like, and inorganic pigments include titanium white, titanium yellow, iron oxide, ultramarine, cobalt blue, chromium oxide green, and graphite. Examples thereof include inorganic pigments such as chromium vermilion, cadmium yellow, and cadmium red, and carbon black pigments. Organic pigments having particularly high lipophilicity are preferred for the method for producing the coloring pigment composition of the present invention. For example, copper phthalocyanine pigments, azo pigments, quinacridone pigments and the like are preferable.

The ratio between the thermoplastic resin and the pigment presscake in the coloring pigment composition of the present invention can be set arbitrarily. The greater the pigment content, the higher the utility value, but requires control over the pour point and viscosity increase, and usually the pigment content of the coloring pigment composition is 50% by weight to 7% by weight.
It is preferably in the range of 0% by weight.

The antioxidant used in the method for producing the coloring pigment composition of the present invention includes, for example, triethylene glycol-bis [3- (3-t-butyl-5-methyl-
4-hydroxyphenyl) propionate], pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 1,
6-hexanediol-bis [3- (3,5-di-t-
Butyl-4-hydroxyphenyl) propionate],
Hindered phenolic antioxidants such as octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 3,5-di-t-butyl-4-hydroxybenzylphosphonate diethyl ester And the like. The amount of the antioxidant added is 0.05% by weight to 5% by weight, especially 0.2% by weight, based on the total weight of the mixture of the thermoplastic resin and the pigment press cake.
The range is preferably from 2 to 2% by weight.

The dispersant used for producing the coloring pigment composition of the present invention includes, for example, a softening point of 70 ° C. to 100 ° C.
And petroleum resins having a molecular weight of 800 to 2,000, paraffin wax, microcrystalline wax, carnauba wax, beeswax, low molecular weight polyethylene, low molecular weight polypropylene, low molecular weight polystyrene, and the like. According to the invention, particularly suitable dispersants are low molecular weight polyethylenes having a number average molecular weight of 1000 to 9000 and a softening point of 100 ° C to 132 ° C.

The amount of the dispersant to be added is selected in the range of 3% by weight to 35% by weight based on the total weight of the coloring pigment composition, and preferably 8% by weight to 25% by weight.

The silane coupling agent used as an optional component in the method for producing a coloring composition of the present invention includes, for example, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy)
Silane, N- (2-aminoethyl) 3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) 3
-Aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, Examples thereof include 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and 3-mercaptotripropyltrimethoxysilane. The silane coupling agent is based on the weight of the mixture of the thermoplastic resin and the pigment press cake,
0.05 wt% to 5 wt%, preferably 0.2 wt% to
It can be used in the range of 2% by weight. The addition of the silane coupling agent can promote the transfer of the pigment to the resin phase.

The method for producing the coloring pigment composition of the present invention comprises the steps of:
Specifically, the first step consists of adding an antioxidant and a dispersing agent to the thermoplastic resin and the pigment press cake, and kneading the mixture by heating to a temperature equal to or higher than the melting point of the thermoplastic resin. This is a step of generating a pigment-containing resin phase by removing the water and removing the separated water.

The kneading of the thermoplastic resin and the pigment in the first step can be carried out by either a batch or continuous kneading method, but the uniformity of the quality of the coloring pigment composition to be produced is ensured. In addition, it is preferable to use a continuous kneader from the viewpoint of improving work efficiency. In particular,
Supplying a fixed amount of each of the thermoplastic resin, the pigment press cake, the antioxidant and the dispersant to a single-screw to multi-screw rotary screw extruder, particularly a pressurized kneader, and heating and pressurizing to perform strong kneading. Thus, the transition of the pigment from the pigment aqueous phase to the resin phase, that is, flushing (phase inversion) is performed. In the first step, a temperature not lower than the melting point of the thermoplastic resin is finally set as the processing temperature. Melting point 100 ° C-1
Since a thermoplastic resin of 30 ° C. is used, the temperature of the flushing of the pigment in the first step is preferably in the range of 100 ° C. to 130 ° C. When the flushing temperature exceeds 130 ° C., the transfer of the pigment to the molten resin on the heated wall surface starts. In addition, a part of the pigment is partially flushed to the low melting point resin. Although the mixing ratio of the thermoplastic resin and the pigment press cake varies depending on the pigment content in the pigment press cake, the mixing ratio should be adjusted so that the pigment content in the obtained pigment composition for coloring becomes 20% by weight to 60% by weight. Is preferred.

In the flushing of the pigment, the kneading machine may be charged with the thermoplastic resin, the pigment press cake, the antioxidant and the dispersant in a full capacity, but a preferable method is to divide the charge into several parts. The way to do it. That is,
A predetermined amount of the pigment press cake is charged, flushed to remove separated water, then a predetermined amount of pigment press cake is added, and after flushing, the separated water is removed. Thus, the efficiency can be improved by sequentially adding the pigment press cake and performing flushing.

It is preferable to add a silane coupling agent during the flushing in the first step from the viewpoint of facilitating the transfer of the pigment to the resin phase.

In the second step, the pigment-containing resin phase obtained by the flushing of the pigment in the first step is heated to completely evaporate and remove the remaining water. Pigment composition can be obtained. A temperature of 100 ° C. or more is adopted as the processing condition, and the pressure can be arbitrarily selected, but may be normal pressure. By such a process, a pigment composition for coloring having a high pigment concentration, excellent dispersibility, excellent clarity and transparency can be obtained.

The coloring pigment composition obtained by the present invention can be used for coloring synthetic fibers and plastic films,
It is widely used as coloring of plastic molded articles, toner recording liquid for copying machines, gravure inks and paints, and is very useful.

Next, a specific embodiment of the present invention will be described.

That is, a polyolefin-based thermoplastic resin is used as the thermoplastic resin having a melting point of 100 ° C. to 130 ° C.
In addition, a hindered phenol antioxidant or a phosphorus antioxidant as an antioxidant, a low molecular weight polyethylene as a dispersant having a melting point of 80 ° C to 110 ° C and a pigment content of 30%
Is added. Pigment press cake
A predetermined amount is divided, a fixed amount is sequentially added, and water is kneaded and separated at each addition to remove water to be separated.

The resin phase in which the pigment has been transferred is heated again, water is evaporated off, and the mixture is kneaded to obtain a coloring pigment composition having improved pigment dispersibility.

The flushing of such pigments is
The thermoplastic resin and the pigment press cake can be continuously subjected to processes such as transfer of pigment into the resin and dehydration in the extruder using, for example, a twin-screw co-rotating screw extruder.

[0031]

【Example】

Example 1 28 parts by weight of a polyethylene resin having a melting point of 105 ° C. (trade name: Sumikacene G807 (product of Sumitomo Chemical Co., Ltd.)) and a phenolic antioxidant (trade name: Irganox 1010 (Ciba Geigy) Product)) 0.5 parts by weight, 21.5 parts by weight of a low molecular weight polyethylene having a softening point of 105 ° C. and 167 parts by weight of a copper phthalocyanine pigment presscake having a pure content of 30% by weight are supplied, and gradually heated with stirring, and finally The temperature is increased to 105 ° C to 110 ° C and kneaded. Water separated and migration of the pigment into the resin occurred. After removing the separated water, 1/3 of the above-mentioned copper phthalocyanine pigment press cake was added, kneading was continued, water was separated and the pigment was transferred into the resin, and this was repeated once more. Was. Kneading was continued at this temperature for 25 minutes.

Next, water was removed from the pressurized kneader, the colored resin layer was heated to 105 ° C., kneaded for 1 hour as it was, and then dried and pulverized to obtain a pigment composition for coloring. . The coloring pigment composition thus obtained was placed on a slide glass and heated and melted, and the dispersibility of the pigment particles was observed with a microscope. As a result, no particles having a size of 30 μm or more were found. Further, the obtained pigment composition for coloring was mixed with a polyethylene resin to form a colored film. As a result, a film having excellent pigment diffusibility and a clear color tone without color unevenness was obtained.

Example 2 28 parts by weight of a polyethylene resin having a melting point of 107 ° C. (trade name: UBE polyethylene F019 (product of Ube Industries, Ltd.)) and a phenolic antioxidant (trade name: Irganox 1010 (Ciba) were added to a pressurized kneader. -Geigy's product)) 0.5 parts by weight, 21.5 parts by weight of low molecular weight polyethylene having a softening point of 103 ° C (trade name: Sunwax (manufactured by Sanyo Chemical Industries, Ltd.)) and 20% by weight of pure quinacridone red pigment. 190 parts by weight of the press cake are supplied, and the mixture is gradually heated while stirring, and the final temperature is set to 105 ° C to 110 ° C.
Heat to a temperature of ° C. and knead. Water separated and migration of the pigment into the resin occurred. After removing the separated water, 1/3 of the above quinacridone red pigment press cake was added, kneading was continued, water was separated and the pigment was transferred into the resin, and this was repeated once more. Was. At this temperature 2
Kneading was continued for 5 minutes.

Next, water was removed from the pressurized kneader, the colored resin layer was heated to 105 ° C., kneaded for 1 hour as it was, and dried and pulverized to obtain a pigment composition for coloring. . The coloring pigment composition thus obtained was placed on a slide glass and heated and melted, and the dispersibility of the pigment particles was observed with a microscope. As a result, no particles having a size of 30 μm or more were found. Further, the obtained pigment composition for coloring was mixed with a polyethylene resin to form a colored film. As a result, a film having excellent pigment diffusibility and a clear color tone without color unevenness was obtained.

Example 3 28 parts by weight of a polyethylene resin having a melting point of 105 ° C. (trade name: Sumikasen G807 (product of Sumitomo Chemical Co., Ltd.)) and a phosphorus-based antioxidant (trade name: Irganox 1222 (Ciba) were added to a pressurized kneader. -Geigy products)) 21.5 parts by weight of low molecular weight polyethylene having a softening point of 105 ° C and 0.5 parts by weight.
167 parts by weight of a copper phthalocyanine pigment presscake of 30 parts by weight and a pure content of 30% by weight and a silane coupling agent of 0.2
5 parts by weight are supplied, and the mixture is gradually heated with stirring, and is heated to a final temperature of 105 ° C to 110 ° C and kneaded. Water separated and migration of the pigment into the resin occurred. After removing the separated water, 1/3 of the above-mentioned copper phthalocyanine pigment press cake was added, kneading was continued, water was separated and the pigment was transferred into the resin, and this was repeated once more. Was. Kneading was continued at this temperature for 25 minutes.

Next, water was removed from the pressurized kneader, and the colored resin layer was heated to 105 ° C., kneaded for 1 hour as it was, and then dried and pulverized to obtain a pigment composition for coloring. . The coloring pigment composition thus obtained was placed on a slide glass and heated and melted, and the dispersibility of the pigment particles was observed with a microscope. As a result, no particles having a size of 30 μm or more were found. Further, the obtained pigment composition for coloring was mixed with a polyethylene resin to form a colored film. As a result, a film having excellent pigment diffusibility and a clear color tone without color unevenness was obtained.

Comparative Example 1 28 parts by weight of a polyethylene resin having a melting point of 105 ° C. (trade name: Sumikasen G807 (product of Sumitomo Chemical Co., Ltd.)) and 167 parts by weight of a copper phthalocyanine pigment press cake having a pure content of 30% by weight were placed in a pressurized kneader. And kneading by heating the final temperature to a temperature of 105 ° C to 110 ° C. Water separated and migration of the pigment into the resin occurred. After removing the separated water, kneading was continued, and kneading was continued at this temperature for 25 minutes.

Next, water was removed from the pressurized kneader, the colored resin layer was heated to 105 ° C., kneaded for 1 hour as it was, and then dried and pulverized to obtain a pigment composition for coloring. . The obtained pigment composition for coloring was placed on a slide glass, heated and melted, and the dispersibility of the pigment particles was observed under a microscope. As a result, a large number of coarse pigment particles of 30 μm or more were present. Further, the obtained pigment composition for coloring was blended with a polyethylene resin to form a colored film. As a result, the film had insufficient pigment diffusivity and a color tone was unclear.

Comparative Example 2 Polyethylene resin having a melting point of 107 ° C. (trade name: UBE polyethylene F022 (a product of Ube Industries, Ltd.)) 20.5
14 parts by weight, powdered copper phthalocyanine pigment (trade name: Chromofine Blu-SR-5020 (product of Dainichi Seika Kogyo Co., Ltd.)), phosphorus antioxidant (trade name: Irganox 1222 (Ciba Geigy) Product)) 0.5 parts by weight and a low molecular weight polyethylene having a softening point of 105 ° C. 21.
After 5 parts by weight was kneaded with a mixing roll at 110 ° C. for 3 hours, it was dried and pulverized to obtain a coloring pigment composition.
The obtained pigment composition for coloring was placed on a slide glass, heated and melted, and the dispersibility of the pigment particles was observed under a microscope. As a result, a large number of coarse pigment particles of 30 μm or more were present. Further, the obtained pigment composition for coloring was blended with a polyethylene resin to form a colored film. As a result, the film had insufficient pigment diffusivity and a color tone was unclear.

Comparative Example 3 A pigment composition for coloring was prepared in the same manner as in Example 1 except that the same amount of the copper phthalocyanine pigment presscake as that used in Example 1 was added at once without being divided and added. Was prepared.

The obtained pigment composition for coloring was placed on a slide glass, heated and melted, and the dispersibility of the pigment particles was observed with a microscope. As a result, many pigment particles having a size of 30 μm or more were present. Further, the obtained pigment composition for coloring was blended with a polyethylene resin to form a colored film. As a result, the film had insufficient pigment diffusivity and had unclear color tone.

[0042]

According to the present invention, a pigment press cake, an antioxidant and a dispersant are added as essential components to a thermoplastic resin, and the mixture is kneaded at a temperature equal to or higher than the melting point of the thermoplastic resin. The pigment is finely dispersed in the resin by allowing it to migrate into the resin, and thereafter, by heating and kneading,
Almost less than 30 μm, a pigment composition for coloring in which the presence of coarse particles of 30 μm or more is not observed can be obtained, and the diffusibility of the pigment as a pigment composition for coloring is extremely good.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 101/00 C08L 101/00 C09C 3/10 C09C 3/10

Claims (5)

[Claims] 1. A pigment presscake having a pigment content of 15% by weight to 80% by weight, an antioxidant and a dispersant having a melting point of 80 ° C. to 110 ° C. are added to a thermoplastic resin having a melting point of 100 ° C. to 130 ° C. By gradually heating the thermoplastic resin and finally kneading at a temperature equal to or higher than its melting point, the pigment is transferred into the thermoplastic resin, separated water is removed, and thereafter, the mixture is heated and kneaded. A method for producing a pigment composition for coloring. 2. The method for producing a coloring pigment composition according to claim 1, wherein the antioxidant is a phenolic antioxidant and / or a phosphorus antioxidant. 3. The amount of the antioxidant added is 0.1% by weight to 5.0% by weight based on the total weight of the composition.
A method for producing the coloring pigment composition according to the above. 4. The method for producing a pigment composition for coloring according to claim 1, wherein the pigment press cake is sequentially added. 5. The method for producing a pigment composition for coloring according to claim 1, wherein a silane coupling agent is further added to the thermoplastic resin, the pigment press cake and the antioxidant.