KR20050102797A - Liquid toner composition - Google Patents

Abstract

A liquid toner composition is disclosed. The liquid toner composition includes a colorant, an organosol, a charge control agent, a carrier liquid, and a coupling agent, and the coupling agent is a titanate-based coupling agent. According to the present invention, it is possible to provide a liquid toner composition capable of maintaining a constant level of dispersibility even after long-term storage at high temperature without impairing the basic physical properties of the liquid toner.

Description

Liquid toner composition

The present invention relates to a liquid toner composition. More specifically, the present invention relates to a liquid toner composition which can maintain excellent dispersibility for a long time without affecting the toner's properties by adding a coupling agent to solve the problem of long-term storage while using organosol as a binder and a dispersant. .

The general image forming process of an electrophotographic image forming apparatus including a copier, a laser printer, a facsimile, and the like is performed by electrostatically uniformly charging the surface of the photoconductor and then scanning the charged surface with a laser (or light) to electrostatically discharge the photoconductor. To form a miracle latent image. Then, the developer (toner) is brought into contact with the photosensitive member to develop the image on the photosensitive member surface, and then the image is transferred to the recording medium and permanently fixed on the recording medium by applying heat and / or pressure.

An electrophotographic image forming apparatus is classified into a dry process and a wet process. A dry electrophotographic image forming apparatus uses a dry type dry toner, and a wet electrophotographic image forming apparatus uses a liquid type liquid toner, that is, a liquid toner. Use The liquid toner is capable of realizing fine toner particles as compared to the dry toner because the toner particles including the colorant and the binder are dispersed in the liquid carrier, and thus have the advantage of realizing a high resolution image. In addition, unlike dry toner, harmful toner dust does not occur, so there is no fear of contaminating the inside or outside of the printer, and printing is possible with a smaller amount of toner compared to dry toner, thereby reducing the cost.

The liquid toner is composed of toner particles formed by constituting a colorant and a binder, a charge control agent for controlling the amount of charge charged to the toner particles, other functional additives, and a carrier liquid in which they are dispersed. Liquid toners can be classified into liquid toner when the binder of the toner is a common commercial resin and organosol liquid toner wherein the binder of the toner is an organosol. U.S. Patent No. 4,925,766, U.S. Patent No. 4,978,598 and the like disclose a method for producing a liquid toner using an organosol and the like.

The organosol functions as a binder in the toner particles, but itself also functions as a dispersant for dispersing the colorant.

Particles of the liquid toner using an organosol as a binder have advantages in that high resolution images can be realized because they have a diameter within the range of 0.1 micron to 5 microns and are stably charged.

Liquid toners using conventional organosols are prepared by incorporating organosols, colorants, and charge control agents into a carrier liquid and milling in an attritor-type milling apparatus. When the liquid toner prepared in this way is left for a short time at room temperature, it is easily redispersed by some shaking, but when it is left for a long time, especially in a high temperature environment, the toner particles are combined and agglomerated and the gravity This sinks into a form separated from the carrier liquid, resulting in a kind of layer separation.

If you try to print with toner that has become difficult to redistribute, it is difficult for liquid toner to enter the developer, and printing may not be possible or, even if possible, cause image bonding due to liquid toner particles that are not sufficiently redispersed. There is this. However, in consideration of the distribution, storage, and the like in the actual use of the liquid toner, long-term storage at high temperature is difficult to avoid, and therefore, development of a liquid toner capable of maintaining the dispersibility of the liquid toner even during long-term storage at a high temperature is required. .

SUMMARY OF THE INVENTION The present invention has been made to meet the above requirements, and an object of the present invention is to provide a metal complex compound to maintain a certain level of dispersibility even when stored for a long time in a high temperature environment within a range that does not impair the properties required for liquid toner. It is to provide a liquid toner composition comprising a coupling agent in the form as an additive.

The liquid toner composition according to the present invention for achieving the above object comprises a colorant, an organosol, a charge control agent, a carrier liquid and a coupling agent, and the coupling agent is a titanate-based coupling agent.

The content of the organosol is in the range of 1 part by weight to 20 parts by weight based on 1 part by weight of the colorant;

The content of the charge control agent is within the range of 0.001 part by weight to 1 part by weight based on 1 part by weight of the colorant;

The content of the carrier liquid is within the range of 10 parts by weight to 100 parts by weight based on 1 part by weight of the colorant; And

The amount of the coupling agent is within the range of 1 part by weight to 10 parts by weight based on 100 parts by weight of the coloring agent and the whole organosol.

The titanate-based coupling agent has the following [Formula 1],

In which R is a C ₁ to C ₂₀ chain or branched alkyl group,

It is preferable that n is a natural number within the range of 10-30, In particular, it is more preferable that R is isopropyl and n is a natural number within the range of 15-20 in the said formula.

The organosol comprises a thermoplastic (co) polymer core insoluble in the carrier liquid and a (co) polymer graft stabilizer covalently bonded to the thermoplastic (co) polymer core, wherein the thermoplastic (co) polymer core in the organosol It is preferable that the mixing weight ratio of the graft stabilizer is 1: 1 to 15: 1.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The liquid toner according to the present invention is a toner particle containing a colorant and an organosol, a charge control agent for charging the toner particles, a carrier liquid in which the toner particles and the charge control agent are dispersed, and toner particles are dispersed in the carrier liquid. It comprises a coupling agent that serves to maintain.

Although the coloring agent which can be used for the liquid toner composition which concerns on this invention can use any well-known dye type pigment or a pigment type coloring agent, It is preferable to use the pigment type coloring agent excellent in thermal stability and light resistance.

Examples of the pigment colorant that can be used in the present invention include colored organic pigments including azo pigments, phthalocyanine pigments, basic dye pigments, quinatridone pigments, dioxacin pigments and condensed azo pigments; Colored inorganic pigments including chromates, ferrocyanides, oxides, sulfide selenides, sulfates, silicates, carbonates, phosphates and metal powders; And black inorganic pigments including carbon black; Etc., but is not limited thereto. The pigment mentioned above can be used individually or in mixture of 2 or more types.

It is preferable to use an organic pigment among the said pigments in consideration of environmental pollution.

For example, copper phthalocyanine, metal blue phthalocyanine such as Pigment Blue (PB) 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, and aluminum, nickel or vanadium as the center metal. Blue and / or green pigments, including phthalocyanine, bridged phthalocyanine dimers / oligomers such as si-bridged phthalocyanine, and the like; Orange pigments including P.O. (Pigment Orange) 5, 13, 43, 71, 72 and the like; Pigment Yellow Yellow pigments including 12, 13, 17, 74, 83, 93, 122, 146, 155, 180, 185, and the like; Pigment Red 48, 57, 122, 146, 147, 176, 184, 186, 202, 207, 238, 254, 255, 269, 270, 272 and the like; Purple pigments including P.V. (Pigment Violet) 1, 19, 23 and the like; And P.V. 19 / P.R. 122 or P.R. Mixed pigments including 146/147 and the like; Etc., but is not limited thereto.

As used herein, the term organosol refers to an organic material in the form of a sol which simultaneously functions as a binder for binding a colorant and a dispersant for dispersing toner particles in a carrier liquid. And an insoluble thermoplastic (co) polymer core and a (co) polymer graft stabilizer covalently bonded to the thermoplastic (co) polymer core.

The method for preparing the organosol first comprises preparing a graft stabilizer in which a monomer forming a graft stabilizer is mixed with a polymerization initiator in a carrier liquid and polymerized to form a shell portion, and then the prepared graft stabilizer is a thermoplastic (nose) forming a core portion. It is prepared by mixing and polymerizing in a carrier liquid together with a polymerizable monomer for a polymer core and a polymerization initiator. The graft stabilizer plays a role of stabilizing the toner particles through the core portion and the graft reaction.

The monomer forming the graft stabilizer is preferably a C ₆ to C ₃₀ (meth) acrylic monomer. For example, alkyl acrylates, alkyl methacrylates, ethylene, propylene, acrylamide, aryl acrylates, aryl methacrylates, high molecular weight alphaolefins, straight or branched alkyl vinyl ethers or vinyl esters, Long-chain alkyl isocyanates, polysiloxanes and polysilanes, and polymerizable synthetic waxes and the like, but are not limited thereto. One or two or more of the monomers described above can be selected and mixed.

Examples of the carrier liquid usable in the formation of the graft stabilizer include aliphatic hydrocarbons, cyclic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbon solvents, silicone oils and waxes, polyethylene waxes, stearic amides or mixtures thereof. However, the present invention is not limited thereto.

The polymerization initiator is an additive for advancing the polymerization additionally to the monomer through radical decomposition with heat or a reducing material. Examples of the polymerization initiator that can be used for forming the graft stabilizer include, but are not limited to, water-soluble or fat-soluble persulfates, peroxides, azobis compounds, and the like. Any one of the compounds described above may be selected and used alone or in combination of two or more thereof.

The graft stabilizer which is the shell part of an organosol is manufactured by mixing a monomer for graft stabilizer formation, a carrier liquid, and a polymerization initiator, and carrying out a polymerization reaction. The graft stabilizer, the polymerizable monomer for thermoplastic (co) polymer cores, and the polymerization initiator are mixed and polymerized in a carrier liquid to form an organosol.

The thermoplastic (co) polymerizable monomers for the core polymer is preferably a (meth) acrylic monomer of the C ₄ to C _30. Examples include methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, trimethyl cyclohexyl methacrylate, behenyl acrylate, octadecyl acrylate, and the like. It is not limited to this. One or two or more types of the above-mentioned monomers can be selected and mixed and used.

In the preparation of organosols, the graft stabilizer is chemically bonded (grafted to the core) with the thermoplastic (co) polymer core or adsorbed onto the core to remain as a whole with the thermoplastic (co) polymer core. Common methods for grafting include random grafting of polyfunctional free radicals, ring opening polymerization of cyclic ethers, ester amides, or acetals, epoxidation, reaction of hydroxy or amino chain transfer agents with terminal unsaturated terminal groups, esterification Reactions (ie, glycidyl methacrylate undergoes esterification with methacrylic acid under a tertiary amine catalyst), and condensation polymerization, and other grafting methods known to those skilled in the art can be used.

In the organosol thus prepared, the mixing weight ratio of the thermoplastic (co) polymer core and the graft stabilizer is preferably in the range of 1: 1 to 15: 1. If the core / shell ratio exceeds 15, the graft stabilizer for stabilizing the organosol is insufficient, and the organosol is not aggregated. If the core / shell ratio is less than 1, the shell and the core are stable. This is because a solution consisting of discrete particulate phases is formed rather than being formed into an organosol dispersion.

The content of the organosol in the liquid toner composition of the present invention is preferably within the range of 1 part by weight to 20 parts by weight with respect to 1 part by weight of the colorant. If the content of the organosol is less than 1 part by weight with respect to 1 part by weight of the colorant, it is difficult to expect a function as a binder. If the content of the organosol is greater than 20 parts by weight, the content of the colorant is relatively low in the toner particles, resulting in poor color clarity in the printed image. do.

The charge control agent is a substance added to the toner composition to control the amount of charge charged to the toner particles. The charge control agent may be combined with the toner particles through various methods such as chemically reacting with the organosol or colorant particles or forming chelates with specific functional groups of the organosol or colorant particles.

Any charge control agent that can be used in the liquid toner composition of the present invention can be used as long as it is known in the art. For example, fatty acid metal salts, sulfo-solcinate metal salts, alkyl-benzenesulfonate metal salts, aromatic carboxylic acid metal salts, sulfonic acid metal salts, polyoxyethylated alkylamines, lecithin, polyvinylpyrrolidone, basic barium petronates and calcium Petronate and the like, but are not limited thereto. Commercially available charge control agents are typically zirconium HEX-CEM from Mooney Chemicals of Cleveland, Ohio.

The content of the charge control agent to be contained in the liquid toner composition may be determined in consideration of various factors such as the composition of the organosol, the molecular weight of the organosol, the particle size of the organosol, the type of colorant used, and the ratio of the organosol to the colorant. In consideration of these factors, the charge control agent included in the liquid toner composition of the present invention is preferably in the range of 0.001 part by weight to 1 part by weight based on 1 part by weight of the colorant. When the content of the charge control agent is out of this range, it is difficult to control the amount of charges charged to the toner particles, so that it is difficult to obtain a desired image and to obtain a clear image because of low OD (optical density) in the image.

The carrier liquid used in the liquid toner composition of the present invention is required to be chemically inert with respect to the material or apparatus used in the image forming apparatus in which the toner is to be used.

Examples of the carrier liquid that can be used in the liquid toner composition of the present invention include aliphatic hydrocarbons such as n-pentane, hexane and heptane; Ring hydrocarbons such as cyclopentane and cyclohexane; Halogenated hydrocarbon solvents such as aromatic hydrocarbons such as benzene, toluene and xylene, chlorinated alkanes, fluorinated alkals and chlorofluorocarbons; Silicone oils and waxes; Polyethylene waxes, branched paraffin waxes and oils; Stearic acid amide and the like, but is not limited thereto. The above-mentioned carrier liquid can be used individually or in mixture of 2 or more types. Examples of commercially available carrier liquids include, for example, Isopar G, Isopar H, Isopar K, Isopar L, Isopar M, Isopar V, and Nopa 12 from Exxon Corporation. (Norpar 12), old woman 15, and so on.

The content of the carrier liquid in the liquid toner composition of the present invention is preferably within the range of 10 parts by weight to 100 parts by weight with respect to 1 part by weight of the colorant. If the content is less than 10 parts by weight, the content of the toner particles is relatively high and the viscosity of the liquid toner is high. Therefore, it is difficult to control the liquid toner, which causes an image to be printed even in the non-image area. This is because the small size of the colorant lowers the OD of the printed image, and the liquid toner is easily consumed, causing frequent replacement.

The liquid toner composition of the present invention comprises a coupling agent. The coupling agent is a kind of functional additive added to the toner composition in order to be able to maintain dispersibility during high temperature long term storage of the liquid toner. As a material that may be included as a coupling agent, a coupling agent known in the art may be used, but it is required to have excellent compatibility with the carrier liquid in order to maintain dispersibility without harming the physical properties required for the liquid toner.

The coupling agent included in the liquid toner composition of the present invention is a titanate-based coupling agent, preferably in the form of a complex compound in which the central metal represented by the above [Formula 1] is titanium.

Wherein R is a C ₁ to C ₂₀ chain or branched alkyl group, n is a natural number within the range of 10 to 30. More preferably, R is isopropyl and n is a natural number within the range of 15 to 20.

In the compound of the formula (1), the R group is a portion which is miscible with the carrier liquid, and the remaining functional group is a portion which binds to the liquid toner particles, i.e., an organosol or a colorant. Therefore, the R group should be a functional group having excellent usability with the carrier liquid, and the remaining functional groups should be functional groups capable of binding to an organosol or a colorant.

The titanate-based coupling agent can be combined with the toner particles in various ways. For example, it may bind to colorant particles or organosol particles through chemical reactions, to bind colorant particles or organosol particles by chemical or physical adsorption, and to chelate the functional groups of the colorant particles or organosol particles. It can also combine by making. Thus, some functional groups of the titanate-based coupling agent are combined with the toner particles, and the remaining functional groups, that is, the R group, are mixed in the carrier liquid to prevent the respective toner particles from binding to each other and the carriers are combined with each of the toner particles. It is possible to maintain a uniformly dispersed state in the liquid. Therefore, it serves to enable long-term storage of the liquid toner by assisting to maintain the toner particles uniformly dispersed in the carrier liquid for a long time.

The content of the coupling agent in the liquid toner composition of the present invention is preferably within the range of 1 part by weight to 10 parts by weight based on 100 parts by weight of the total colorant and the organosol, that is, the total solid content of the liquid toner. When the content of the coupling agent is less than 1 part by weight based on 100 parts by weight of the total solid content of the liquid toner, the coupling effect is not large, and thus it is difficult to expect the effect of maintaining dispersibility, and the content of the coupling agent is 100 parts by weight of the liquid toner. If it is more than 10 parts by weight, the coupling agent in the form of a complex of a metal salt such as a charge control agent is not preferable because it may affect the charge amount charged to the toner particles, which may affect the electrical properties of the liquid toner.

A specific method for producing the liquid toner composition according to the present invention will be described through the following examples, and this is compared with a comparative example.

{Example}

Example 1

Preparation of Graft Stabilizers

Old woman 12 (made by Exxon) 2557 g

Trimethylcyclohexyl methacrylate (TCHMA) 849 g

27 g of 2-hydroxyethyl methacrylate (HEMA)

V601 (polymerization initiator, manufactured by Wakochem, Japan,

13 g of dimethyl 2,2'-azobis (2-methylpropionate)

The materials were mixed and reacted for 16 hours while stirring at a rate of 250 rpm under a nitrogen gas atmosphere at a temperature of 70 ℃. The reaction mixture was then heated at 90 ° C. at 250 rpm for 1 hour while removing residual V601.

14 g of dibutyltin dilaurate (DBTDL, manufactured by Aldrich Chemical Company) and 41 g of 3-isoprophenyl dimethylbenzyl isocyanate (TMI, manufactured by Cytec Industries) were added to the reaction mixture. And it was reacted for 6 hours while stirring at a rate of 250rpm under nitrogen gas atmosphere at 70 ℃ temperature to prepare a graft stabilizer.

The graft stabilizer thus prepared is a copolymer of HEMA comprising TCHMA and TMI side chains.

Preparation of Organosol

187 g of the graft stabilizer prepared above

Old woman 12 2934 g

325 g of ethyl methacrylate (EMA)

49 g of ethyl acrylate (EA)

6 g of V601 (made in Wako-Chem Japan)

The material was mixed and then reacted for 16 hours while stirring at 250 rpm under a nitrogen gas atmosphere at a temperature of 75 ° C. to prepare a mixture containing organosol. This mixture was then cooled to room temperature.

Organosol was obtained by adding 350 g of n-heptane to the cooled mixture and removing residual monomer from the mixture using a rotary evaporator equipped with a dry ice / acetone condenser and operated at vacuum temperature of 15 mmHg at a temperature of 97 ° C.

The organosol thus prepared was cooled to room temperature to give an opaque liquid dispersion.

Preparation of Liquid Toner Composition

P.B. 15: 4 (product made from Sun Chemical) 9.43 g

435.2 g of the prepared organosol (% solid = 13%)

Zirconium-HEXCEM (2.4%) 2.75g

KR-TTS (AFT Co., Ltd., coupling agent) 0.660 g

Old woman 12 (made by Exxon) 152.72 g

The material was placed in a milling vessel in the attriter form, and then 1200 g of zirconium beads were put together and milled at 42 ° C. for 3 hours with stirring at 5000 rpm to obtain about 600 g of the liquid toner composition.

Example 2

In Example 1, except that 1.320 g of KR-TTS was added, it was prepared in the same manner as in Example 1 to obtain about 600 g of the liquid toner composition.

Comparative example

Except that KR-TTS was not added in Example 1, it was prepared in the same manner as in Example 1 to obtain about 600 g of a liquid toner composition.

{Evaluation method and evaluation result}

Assessment Methods

(1) Measurement of particle size

Volume average particle diameter and number average particle diameter immediately after preparation of the liquid toner compositions of Examples 1, 2 and Comparative Example using Horiba 910 and volume average particle diameter and number average particle diameter of each liquid toner composition after being left in a 50 ° C. oven for 6 days. Was measured.

(2) electrical property measurement

In order to measure the change in the electrical properties of the liquid toner, the Q / M (charge per unit weight of liquid toner) was measured immediately after the preparation of the liquid toner compositions of Examples 1 and 2 and after being left in a 50 ° C. oven for 6 days. It was.

Q / M was first measured by placing a liquid toner diluted to a certain concentration between indium tin oxide (ITO) glass and iron plate, and then applying a 300 kV / m electric field to dry the liquid toner adsorbed on the ITO glass. The amount of charge per unit weight (μC / g) was measured by calculating the current flowing between them.

(3) Optical Density Measurement

The liquid toner prepared on the organic photosensitive drum was developed, and then the image on the drum was taped to measure the image density of the image area and the non-image area.

(4) high temperature storage stability evaluation

The liquid toners of Examples 1, 2 and Comparative Example were left in a 50 ° C. oven for 6 days and then stirred for 5 minutes at the weight of the total liquid toner (X), the weight of the remaining agglomerated ink mass (Y), and 600 rpm. The weight (Z) of the remaining ink mass was measured to calculate solidification rate and redispersibility.

Solidification rate = Y / X × 100 (%)

Redispersion = (Y-Z) / Y × 100 (%)

Evaluation results

The evaluation results according to the evaluation method are shown in the following [Table 1].

result Volume average particle diameter (㎛) Number average particle diameter (㎛) Q / M (μC / g) △ Q / M (μC / g) Image area image density (OD) Non-Image Area Image Concentration (OD) Solidification rate (%) Redispersibility (%) Right after manufacturing After high temperature storage Right after manufacturing After high temperature storage Right after manufacturing After high temperature storage Example 1 4.03 4.43 0.27 0.27 256 242 -14 1.98 0.01 32 76.3 Slashing Example 2 3.73 4.27 0.28 0.28 288 276 -12 1.98 0.01 20 82.4 Comparative example 4.06 4.46 0.23 0.21 169 107 -62 1.99 0.01 70 Not measurable

As can be seen from the above table, the volume average particle diameter and the number average particle diameter of Examples 1, 2 and Comparative Examples do not show a large change immediately after preparation and after high temperature storage. In other words, it can be seen that the effect of the liquid toner added with the coupling agent according to the present invention on the toner particle size is not as large as that of the conventional liquid toner.

In the case of the electrical properties, if the difference in Q / M is included in the range of +15 to -15, it is within the error range, in the case of Examples 1 and 2, ΔQ / M immediately after manufacture and after high temperature storage is -14 and As -12, it can be seen that stable electrical properties are maintained with little change within the error range. However, the liquid toner of the comparative example which did not contain the coupling agent according to the present invention showed a large change of ΔQ / M immediately after preparation and after high temperature storage as -62, and the electrical properties of the liquid toner were significantly worsened after high temperature storage. It can be seen that. This means that after high temperature storage of the liquid toner, the dispersibility of the toner was deteriorated and the electrical conductivity was also worsened.

As a result of the measurement of the image density, the image area image density and the non-image area image density immediately after each preparation of the liquid toners of Examples 1, 2 and Comparative Example showed almost similar values, which was a liquid containing a coupling agent according to the present invention. Indicates that the toner does not harm the basic physical properties of the liquid toner.

In the solidification rate of the liquid toner, the degree of solidification of 32% and 20% after high-temperature storage in Example 1 and Example 2 was not large, but in the comparative example, the solidification rate was 70%, and a substantial portion was solidified. It can be seen that.

Further, even though the liquid toners of Examples 1 and 2 were solidified, they could be re-dispersed at about 76.3% and 82.4%, respectively, by stirring, but the liquid toners of Comparative Examples could not be redispersed.

Looking at the above results, it can be seen that the liquid toner composition including the titanate-based coupling agent of the present invention can maintain the dispersibility of the liquid toner even after high temperature storage without impairing the basic physical properties of the liquid toner.

According to the present invention as described above, by adding a titanate-based coupling agent as an additive to the liquid toner composition, it is possible to improve the maintenance of dispersibility even after long-term storage at high temperature without inhibiting the basic physical properties of the liquid toner. There is an effect of providing a liquid toner composition.

Although the above has been illustrated and described with respect to the preferred embodiment of the present invention, the present invention is not limited to the specific preferred embodiment described above, the present invention without departing from the gist of the invention claimed in the claims Various modifications can be made by those skilled in the art, and such modifications are within the scope of the claims.

Claims (5)

Including colorants, organosols, charge control agents, carrier liquids and coupling agents, And the coupling agent is a titanate-based coupling agent. The method of claim 1, The content of the organosol is in the range of 1 part by weight to 20 parts by weight based on 1 part by weight of the colorant; The content of the charge control agent is within the range of 0.001 part by weight to 1 part by weight based on 1 part by weight of the colorant; The content of the carrier liquid is within the range of 10 parts by weight to 100 parts by weight based on 1 part by weight of the colorant; And The amount of the coupling agent is in the range of 1 part by weight to 10 parts by weight based on 100 parts by weight of the coloring agent and the whole organosol. The method of claim 1, The titanate-based coupling agent has the following formula, In which R is a C ₁ to C ₂₀ chain or branched alkyl group, n is a natural water in the range of 10 to 30. The method of claim 3, wherein Wherein R is isopropyl and n is a natural number within the range of 15 to 20. The method of claim 1, The organosol comprises a thermoplastic (co) polymer core insoluble in the carrier liquid and a (co) polymer graft stabilizer covalently bonded to the thermoplastic (co) polymer core, wherein the thermoplastic (co) polymer core in the organosol And a mixed weight ratio of the graft stabilizer is 1: 1 to 15: 1.