JPH03292370A - Coloring agent - Google Patents

Abstract

PURPOSE:To obtain a coloring agent which gives a toner for electrophotography, a paint, a printing ink, etc., good at the fixability and adhesion to paper, wood, metal, etc., and at the tone and density of an image by incorporating pigments and a silicone oil as main components. CONSTITUTION:A coloring agent is produced by incorporating pigments and a silicone oil as main components. Particularly, it is advantageous to use a dialkylsilicone oil of the formula [wherein R<1>-R<8> are each -CnH2n+1(n=1-20); and x is an integer of 0, 1 or more], since a coloring agent is obtained which is excellent in dispersibility. Especially, it is preferred to use a dimethylpolysiloxane. As the silicone oil, in addition to the above, a cyclic dialkylsilicone oil, a cyclic alkylphenysilicone oil and an alkylphenysilicone oil can be used. A coloring agent is obtained which gives a toner for electrophotography, a paint, a printing ink, etc., good at the fixability and adhesion to paper, wood, metal, etc., and at the tone and density of an image.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a colorant used in electrophotographic developers, paints, printing inks, and the like.

[Conventional technology]

For example, an electrophotographic image in which a coloring agent obtained by kneading and pulverizing an organic or inorganic pigment such as carbon black or phthalocyanine blue with a resin is uniformly dispersed as a toner in a highly insulating and low dielectric constant carrier liquid. Developers, paints, printing inks, and the like are well known. However, this colorant usually has strong secondary agglomeration of organic or inorganic pigments, so it is difficult to use ball mills, attritors, etc.
Even when dispersed in a vehicle using a black roll mill or the like, primary particles could not be easily dispersed.

By the way, the flushing method (specially known as the flashing method) in which a colorant is produced by dispersing carbon black or the like in water, then kneading it with a resin solution to replace the water surrounding the carbon black with the resin solution, and then removing the water and solvent. JP-A-56-80055 and JP-A-58-14141) are known.

However, even with this flushing method, since carbon black is not hydrophilic, it does not disperse well in water and cannot be atomized, and as described above, it is difficult to disperse the carbon black down to secondary particles.

When colorants produced using such conventional flushing methods are used as electrophotographic toner particles and used in electrophotographic liquid developers, the dispersibility in the carrier liquid is insufficient, so the gradation cannot be achieved at high concentrations. It has been difficult to form images with excellent properties and fixability.

However, as an improvement to the method for producing colorants using such a flushing method, (a) when dispersing colorants such as carbon black in water, anionic, nonionic or cationic surfactants, polymeric synthetic polymer dispersants, etc. (b) Dispersing a coloring agent such as carbon black using humic acid, humic acid salts or humic acid derivatives, and further adding low molecular weight polyethylene, natural resin modified resin, dammar, copal, shellac, gum rosin, styrene, etc. −
A method of kneading butadiene copolymer, polyolefin, etc. to coat pigment particles has been studied or disclosed (Japanese Unexamined Patent Publication No. 102253/1983).

However, the colorant obtained by the above method (a) has a drawback that its dispersibility in the carrier liquid is still insufficient. Furthermore, the colorant obtained by the above method (b) does not necessarily blend well with other resins, and therefore has the drawback of being slightly inferior in adhesiveness, gradation, and image density.

[Problem to be solved by the invention]

It is an object of the present invention to provide a coloring agent that provides electrophotographic toners, paints, printing inks, etc. that can be well fixed and adhered to paper, wood, metal plates, etc., and have good gradation and image density. purpose.

[Means to solve the problem]

According to the present invention, a coloring agent containing a pigment and silicone oil as main components is provided.

In other words, the present inventors believe that the colorant using silicone oil has low compatibility with other resins and low melt viscosity when heated and mixed, so it is not only possible to disperse the pigment itself, but also to improve the coloring obtained. It has also been found that the agent can be easily dispersed and blended with other resins.

The present invention was completed based on this knowledge.

The present invention will be explained in more detail below.

In the present invention, examples of the silicone oil used as an essential component of the colorant include dialkyl silicone oils shown in bottom (1) below; cyclic polydialkylsiloxanes or cyclic polyalkylphenylsiloxanes; and alkylphenylsiloxanes. In addition, higher fatty acid-modified silicone oil, methylchlorinated phenyl silicone oil, alkyl-modified silicone oil, methylhydrogen silicone oil, amino-modified silicone oil, epoxy-modified silicone oil, etc. can be used.

[However, R1, R", R", R, R', R5, R'
, R', R'' is -〇nH2n+□ (n=1 to 20)
and these may be the same or different. X is O or an integer of 1 or more. ] When the dialkyl silicone oil represented by general ship bottom 1) is used,
In particular, it is advantageous in that a colorant with excellent dispersibility can be obtained. Among them, it is advantageous to use dimethylpolysiloxane. Moreover, the viscosity of the silicone oil represented by this bottom (I) at 25°C is 0.01・-1,000,0
OOcs (centistokes) are preferred. Furthermore, it is desirable to use a ship bottom (1) in which X is 1 to 20,000.

Furthermore, when a cyclic polydialkylsiloxane or a cyclic polyalkylphenylsiloxane is used, it is advantageous for producing gloss in the resulting colorant. When alkylphenylsiloxane (especially methylphenyl silicone oil is preferably used) is used, the introduction of phenyl groups (5 to 50 mol%) improves solubility, resulting in improved dispersion stability of the colorant. It is advantageous to raise the

Specific examples of these various silicone oils are as follows.

(1) Examples of dialkyl silicone oils: (n) Cyclic polydialkylsiloxane and cyclic polyalkylphenylsiloxane (phenyl group content is 5, 10, 20, respectively)
．． 50 mol%) Examples: cyclic polydimethylsiloxane, cyclic polymethylphenylsiloxane cyclic polydiethylsiloxane, cyclic polyethylphenylsiloxane cyclic polydibutylsiloxane, cyclic polybutylphenylsiloxane cyclic polydihexylsiloxane, cyclic polyhexylphenylsiloxane cyclic polydibutylsiloxane Examples of laurylsiloxane, cyclic polymethylchlorophenylsiloxane, cyclic polydistearylsiloxane, and cyclic polymethylbromphenylsiloxane (III) alkylphenyl silicone oil: Commercially available examples of these silicone oils include KF-96L manufactured by Shin-Etsu Chemical Co., Ltd. (0,65,1,0,1,5
, 2,0 centistokes (cs)), KF-96 (1
0,20,30,50,500゜1000.3000(
cs)), KF-56, KF-58, KF-54, etc., and TSF of Toshiba Silicone Co., Ltd. lit.
451 series, TSF456 series, TSF410
,411,440,4420゜484.483,431
, 433 series, THF450 series, TSF40
4.405, 406, 451-5A, 451-10A,
437 series, TSF4440.400,401,4
300,4445,4700,4450,4702,4
Examples include the 73G series, the TSF434, 4600 series, and MS-200 manufactured by Toshi Silicone Co., Ltd.

Other solvents can be mixed with the above silicone oil to the extent that the properties of the silicone oil are not impaired. Such solvents include aromatic hydrocarbon solvents such as toluene, xylene, and benzene; ethers; esters; alcoholic solvents; n-hexane, n-octane,
Aliphatic hydrocarbons such as 1ro-octane, 1ro-dodecane, and mixtures thereof (commercially available products include Isopar H and G manufactured by Exxon Chemical Company).

L, V, etc.). The mixing ratio of such other solvents is 0.1 to 100 parts by weight of silicone oil.
Approximately 500 parts by weight.

Examples of pigments (carbon black, organic pigments) used in the present invention include the following.

As carbon black, furnace black, acetylene black, channel black, etc. can all be used, and commercially available products include Printex G, Special Black 15, Special Black 4, Special Black 4-B (manufactured by Degussa), Mitsubishi #44, #30, HA
-11, MA-100 (manufactured by Mitsubishi Carbon), Raven 30, Raven 40, Conductex SC (manufactured by Columbia Carbon), Regal 800.400,
660 and Black Pearl L (manufactured by Cabot) are known.

Organic pigments include phthalocyanine blue, phthalocyanine green, sky blue, rhodamine lake, malachite green lake, methyl violet lake, peacock blue lake, night green B, night green Y, naphthol yellow S, resol fast yellow 2G, permanent red 4R, Brilliant Fast Scarlet, Hansa Yellow, Benzidine Yellow Resole Red, Lake Red C, Lake Red D
, Brilliant Carmen 6B, Permanent Red F5
R, pigment scarlet 3B and Bordeaux 10B
etc.

In the present invention, the ratio of silicone oil to pigment used is 0.01 to 3.0 parts by weight of silicone oil to 1 part by weight of pigment.
A suitable amount is 0 parts by weight, preferably 0.1 to 2.0 parts by weight.

In addition, a part of the silicone oil can be used, such as natural resin-modified coal resin, natural resin-modified maleic resin, dammar, copal, shellac, gum rosin, hardened rosin, ester gum glycerin ester-modified maleic resin, styrene-butadiene copolymer, and It is possible to substitute polyolefin, a copolymer such as polyolefin, wax, etc., but in that case, at least 20% by weight of the entire resin (including waxes) needs to be silicone oil.

Among the colorants of the present invention, the colorant in which the pigment is coated with a specific resin can be obtained by a flushing method, but other colorants of the present invention can be obtained by adding humic acid, humate salt, or humic acid during the pigment dispersion step. Obtained by using derivatives.

Humic acid is an alkali-soluble amorphous polymeric organic acid contained in young coals such as peat and lignite with a low degree of coalification.

This humic acid includes trophumic acid in natural and artificial products)
They are broadly classified into two, and any of them can be used in the present invention. Humic acid process products are CH-type and C-type due to differences in molecular weight distribution.
There are HA type and CHN type, as well as acid type and salt type with Na, NH4, etc., and both can be used.

Since humic acid, humic acid salts, or humic acid derivatives (hereinafter referred to as "humic acids") are well adsorbed to pigments, they are advantageous for atomization and dispersion to approximation of next-order particles and for improving dispersion stability (long-term storage). It is.

The colorant is manufactured using the above raw materials in the following manner. Add humic acids to the pigment water-containing liquid at a rate of 0.1 to 3
0% by weight and well mixed in a kneader, or a pigment water-containing liquid to which no humic acids are added is further mixed well together with a resin solution in a kneader called a flasher. As a result, the water present around the pigment is replaced by the resin solution. The water is discarded from the kneader, and the pigment dispersed in the resin solution is dried to remove the solvent and obtain a lump. Colorant powder is then obtained by crushing this mass. This colorant consists of primary pigment particles coated with resin, and is used in printing inks, paints, etc.
It is useful for toners for electrostatic photography.

For example, in order to prepare an electrostatographic liquid developer using the colorant produced as described above, the colorant may be dispersed in a carrier liquid together with a binder resin.

As the carrier liquid, petroleum-based aliphatic hydrocarbons with high insulation properties (electrical resistance 10"3 Ωcm or more) and low dielectric constant (dielectric constant 3 or less), n-hexane, ligroin, n-hebutane, n-pentane, India In addition to decane, isooctane, etc., halogen derivatives thereof such as carbon tetrachloride, perchloroethylene, etc. may be mentioned. Commercially available products of the petroleum aliphatic hydrocarbons include Isopar E, Isopar 6, manufactured by Exxon, Isopar, Isopar H, Isopar K,
There are Naphtha Kumi 6, Trubec 100, etc., but it is more effective to use silicone oil as a dispersion medium.

〔Effect of the invention〕

As described above, the colorant according to the present invention has good image density, gradation, and fixing performance. Further, when carbon black is used as the pigment, the degree of blackness is further increased, which is considered to indicate that carbon black is well dispersed in the flushing colorant of the present invention.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 Water
500g printex
30g Alkaline Blue 2
0g humic acid Lo
After stirring well with a flasher, 600 g of dimethyl silicone oil (viscosity 0.65 cs) was further added to the flasher and kneaded to produce the colorant of the present invention.

Examples 2 to 18 Seventeen types of colorants were produced in the same manner as in Example 1 except that only the raw materials were replaced with those shown in Table 1.

Next, 20 g of these colorants were mixed with 50 g of polylauryl methacrylate/acrylic acid (90/10) in dimethyl silicone oil (0.65 cs) (Examples 1 to 6).
), cyclic polydimethylsiloxane (Examples 7 to 12) and methylphenyl silicone oil (phenyl group content 20 moles (Examples 13 to 18)) were added to 100 g and kneaded in a ball mill for 72 hours to make a concentrated toner. Sog of 2Q dimethyl silicone oil 0.65 (
as) (Examples 1 to 6), cyclic polydimethylsiloxane (Examples 7 to 12) and methylphenyl silicone oil (phenyl group content 20 mol%) (Examples 13 to 1)
8) to prepare a developer.

When these developers were used for copying with a commercially available copying machine (Copy DT-1200 manufactured by Ricoh Co., Ltd.), the results shown in Table 2 were obtained.

Table-2

Claims (3)

[Claims] (1) Coloring agent whose main ingredients are pigment and silicone oil. (2) The coloring agent according to claim (1), wherein the silicone oil is at least one selected from dialkyl silicone oil, cyclic dialkyl silicone oil, cyclic alkylphenyl silicone oil, and alkylphenyl silicone oil. (3) The coloring agent according to claim (1) or (2), which is produced by a flushing method.