CN113956687A

CN113956687A - Negative photoresist and preparation method thereof, and composite carbon black and preparation method thereof

Info

Publication number: CN113956687A
Application number: CN202111449177.6A
Authority: CN
Inventors: 姜庆; 廖辉华; 宋智辉; 李荣荣
Original assignee: HKC Co Ltd; Changsha HKC Optoelectronics Co Ltd
Current assignee: HKC Co Ltd; Changsha HKC Optoelectronics Co Ltd
Priority date: 2021-11-30
Filing date: 2021-11-30
Publication date: 2022-01-21

Abstract

The invention provides a nature photoresist and a preparation method thereof, and composite carbon black and a preparation method thereof. The composite carbon black comprises a carbon black main body and at least one first active group grafted on the carbon black main body, wherein the first active group simultaneously has an epoxy group and an amide group, and the first active group enables the composite carbon black to have self-dispersion capacity. Therefore, when the composite carbon black is used for preparing the negative photoresist, the uniform dispersion of the composite carbon black can be realized without additionally adding a carbon black dispersing agent, the quality of the negative photoresist is improved, and the display quality of the TFT-LCD is further improved.

Description

Negative photoresist and preparation method thereof, and composite carbon black and preparation method thereof

Technical Field

The invention relates to the technical field of electronic display, in particular to negative photoresist and a preparation method thereof, and composite carbon black and a preparation method thereof.

Background

A Thin Film Transistor-Liquid Crystal Display (TFT-LCD) is a mainstream flat panel Display device in the market due to its advantages of large Display size, energy saving, environmental protection, high definition, lightness and thinness.

The TFT-LCD includes three main parts of an Array substrate, a liquid crystal and a CF substrate, wherein the CF substrate has a Black Matrix (BM) thereon, which functions to separate sub-pixels of three primary colors of RGB from each other to prevent color mixing. The BM is typically made using a negative photoresist. The negative photoresist is prepared by mixing alkali soluble resin, photoinitiator, pigment, dispersant, functional additive, polymerization monomer, polymerization oligomer and solvent according to a certain proportion.

The Optical performance of BM negative photoresists used in TFT-LCDs was evaluated using Optical Density (OD), and generally, good light-shielding characteristics were exhibited at an OD value of 3.0. The pigment in the BM negative photoresist uses carbon black, the particle size of the carbon black can be as low as 5nm, and carbon black particles are not isolated in a photoresist system, but a plurality of particles are mutually interpenetrated in each component of the photoresist through a carbon crystal layer. Carbon black having a small particle size is highly likely to aggregate when dissolved due to a large specific surface area and a large surface electrostatic force, and contact points between individual carbon black aggregates are increased and cohesion between the aggregates is stronger, thereby making it difficult to separate carbon black particles. When the dispersion performance of the carbon black is not good and aggregation occurs, small black spots are easily generated on BM pixels, and therefore the display quality of the TFT-LCD is reduced.

It is to be noted that the information disclosed in the above background section is only for enhancement of understanding of the background of the invention.

Disclosure of Invention

The invention aims to provide composite carbon black with good dispersibility and a preparation method thereof, and a negative photoresist prepared from the composite carbon black and a preparation method thereof, so as to solve the problems in the prior art.

Additional features and advantages of the invention will be set forth in the detailed description which follows, or in part will be obvious from the description, or may be learned by practice of the disclosure.

According to one aspect of the present invention, a composite carbon black is provided, which includes a carbon black body and at least one first active group grafted to the carbon black body, wherein the first active group has both an epoxy group and an amide group.

In some embodiments of the present invention, the composite carbon black further comprises at least one second reactive group grafted to the carbon black body, the second reactive group comprising an amide group.

According to one aspect of the present invention, there is provided a method for preparing a composite carbon black, comprising the steps of:

weighing 50-75% of silicon carbon black, 30-45% of additive, 1-3% of heat stabilizer, 1-3% of grinding aid and 10-15% of thermal dispersant according to mass fraction percentage;

uniformly mixing the silicon carbon black, the additive and the thermal dispersant, heating and refluxing for 6-10 h at 80-150 ℃, taking out, washing with absolute ethyl alcohol, filtering and drying to obtain a first product;

dispersing the thermal dispersant and the first product in the thermal dispersant, slowly heating to 300-400 ℃ and keeping for 1-3h, and then slowly cooling to room temperature to obtain a second product;

and adding the grinding aid into the second product, and crushing, grinding, ball-milling and sieving to obtain the composite carbon black.

In some embodiments of the invention, further comprising the steps of:

immersing the composite carbon black in strong acid, continuously stirring, heating to 100 ℃, preserving heat for 3-5h, and filtering to obtain acidic composite carbon black;

immediately adjusting the pH value of the acidic composite carbon black to be neutral by using ammonia water, then adding the acidic composite carbon black into ethyl acetate and petroleum ether in a volume ratio of 1:15, and filtering, ball-milling and sieving to obtain the improved composite carbon black.

In some embodiments of the invention, the additive comprises (3- (oxiran-2-yl) propyl) carbamate

T-butyl ester, t-butyl 1-oxa-5-azaspiro [2,5] octane-5-carboxylate and/or methyl 1-oxa-5-azaspiro [2,5] octane-5-carboxylate.

In some embodiments of the present invention, the heat stabilizer has the general formula M (coor)2, wherein M is cadmium, barium, calcium, zinc, magnesium or strontium, R is a long chain saturated hydrocarbon group having the general formula CnH2n +1, and n has a value of 1 to 6.

In some embodiments of the invention, the grinding aid comprises a metal inorganic salt;

the thermal dispersant comprises polyvinylpyrrolidone.

According to one aspect of the invention, a negative photoresist is provided, which comprises the following components in percentage by mass: 8.5 to 10.5 percent of alkali soluble resin, 5.0 to 8.0 percent of the composite carbon black, 5.6 to 11.0 percent of monomer, 1.0 to 3.0 percent of oligomer monomer, 0.1 to 0.3 percent of photoinitiator and 75.0 to 83.0 percent of solvent.

In some embodiments of the present invention, the alkali-soluble resin is obtained by subjecting 13% to 18% of methacrylic acid, 17% to 23% of methyl methacrylate, 20% to 28% of butyl methacrylate, 17% to 23% of benzyl methacrylate, 1% to 3% of a hydrogen donor reagent, 7% to 10% of an excess thermal initiator, and 25% to 40% of a solvent to reduced pressure heating and gradient elution.

According to an aspect of the present invention, there is provided a method of manufacturing a negative photoresist, comprising the steps of:

weighing 8.5-10.5% of alkali soluble resin, 5.0-8.0% of the composite carbon black, 5.6-11.0% of monomer, 1.0-3.0% of oligomer monomer, 0.1-0.3% of photoinitiator and 75.0-83.0% of solvent according to the mass fraction percentage;

adding the soluble resin, the monomer, the oligomer monomer and the composite carbon black into a stainless steel cylinder which is completely light-tight and sealed, and fully stirring and uniformly mixing to obtain a mixture A;

adding the photoinitiator and the solvent into a stainless steel cylinder which is completely light-tight and sealed, and fully stirring and uniformly mixing to obtain a mixture B;

and simultaneously adding the mixture A and the mixture B into a completely sealed and lightproof stainless steel cylinder, and fully and uniformly stirring to obtain the negative photoresist.

According to the technical scheme, the invention at least has the following advantages and positive effects:

the composite carbon black comprises a carbon black main body and at least one first active group grafted on the carbon black main body, wherein the first active group simultaneously has an epoxy group and an amide group, and the first active group enables the composite carbon black to have self-dispersion capacity.

Therefore, when the composite carbon black is used for preparing the negative photoresist, the uniform dispersion of the composite carbon black can be realized without additionally adding a carbon black dispersing agent, the quality of the negative photoresist is improved, and the display quality of the TFT-LCD is further improved.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the disclosure. It is to be understood that the drawings in the following description are merely exemplary of the disclosure, and that other drawings may be derived from those drawings by one of ordinary skill in the art without the exercise of inventive faculty. In the drawings:

FIG. 1 shows a schematic diagram of the structural formula of one embodiment of the composite carbon black of the present invention.

FIG. 2 shows a schematic diagram of the structure of yet another embodiment of the composite carbon black of the present invention.

FIG. 3 shows a flow chart of a method of making the composite carbon black of the present invention.

FIG. 4 shows Fourier infrared spectra of a commercially available carbon black, one of the additives of the present invention, and a composite carbon black of the present invention.

FIG. 5 is a schematic diagram showing the principle comparison of dispersibility between a conventional commercially available carbon black and a composite carbon black of the present invention.

Fig. 6 is a flow chart illustrating a method of manufacturing a negative photoresist in accordance with the present invention.

Fig. 7 shows a TEM spectrum of a negative photoresist in the present invention.

Fig. 8 shows a TEM spectrum of a dry film prepared by the negative photoresist of the present invention.

FIG. 9 is a graph showing the linear relationship between the film thickness and the optical density value in the present invention.

Detailed Description

Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments may, however, be embodied in many different forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art.

Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the disclosure. One skilled in the relevant art will recognize, however, that the subject matter of the present disclosure can be practiced without one or more of the specific details, or with other methods, components, devices, steps, and so forth. In other instances, well-known methods, devices, implementations, or operations have not been shown or described in detail to avoid obscuring aspects of the disclosure.

The flow charts shown in the drawings are merely illustrative and do not necessarily include all of the contents and operations/steps, nor do they necessarily have to be performed in the order described. For example, some operations/steps may be decomposed, and some operations/steps may be combined or partially combined, so that the actual execution sequence may be changed according to the actual situation.

The invention provides composite carbon black which has self-dispersion performance, can be uniformly dispersed in the process of preparing negative photoresist without additionally adding a carbon black dispersing agent, improves the quality of the negative photoresist, and further improves the display quality of a TFT-LCD (thin film transistor-liquid crystal display).

The composite carbon black will be specifically described below.

The composite carbon black comprises a carbon black main body and at least one first active group grafted on the carbon black main body. The first reactive group has both an epoxy group and an amide group.

Referring to FIG. 1, a schematic diagram of one of the structural formulas of the composite carbon black is shown. Specifically, the structural formula is schematically shown as follows:

wherein,

denotes a carbon black body onto which two first reactive groups are grafted.

Each first active group simultaneously has an epoxy group and an amide group, and the epoxy group and the amide group are positioned on the same carbon chain and are grafted with the carbon black main body. It is understood that the epoxy group and the amide group are linked in series and then grafted to the carbon black main body. The first active groups are connected in parallel, namely, each first active group is respectively connected with the carbon black main body in a grafting way. The number of first reactive groups may be set according to the specific number.

The first active group, namely the epoxy group and the amide group, provides rich electron cloud density for the silicon carbon black, so that the surface charge of the silicon carbon black is rich, and the charges on the surfaces of the silicon carbon blacks are basically the same, so that the silicon carbon black and the silicon carbon black are mutually repelled due to static electricity and are not easy to gather, and the composite carbon black has better dispersing performance.

Referring to FIG. 2, a schematic diagram of another structural formula of the composite carbon black is shown. Specifically, the structural formula is schematically shown as follows:

wherein,

which means a carbon black body onto which both a first active group and a second active group are grafted.

The second active group is an amide group. And a plurality of second movable groups are respectively grafted and connected with the carbon black main body. The number of second reactive groups may be set according to the specific number.

The increase of the second active group, namely the increase of the amide group, increases the charge on the surface of the silicon carbon black, and further increases the dispersion performance of the composite carbon black.

Referring to fig. 3, the present invention further provides a method for preparing the composite carbon black, comprising the following steps:

s11, weighing 50-75% of silicon carbon black, 30-45% of additive, 1-3% of heat stabilizer, 1-3% of grinding aid and 10-15% of heat dispersant according to mass fraction percentage.

Wherein, the additive comprises epoxy group and amide group.

Specifically, the additive includes at least one of tert-butyl (3- (oxiran-2-yl) propyl) carbamate, tert-butyl 1-oxa-5-azaspiro [2,5] octane-5-carboxylate, and methyl 1-oxa-5-azaspiro [2,5] octane-5-carboxylate. That is, the additive may be one of the above additives, may be a mixture of two of the above additives, or may be a mixture of three of the above additives.

The structural formula of tert-butyl (3- (oxiran-2-yl) propyl) carbamate is as follows:

the structural formula of the 1-oxa-5-azaspiro [2,5] octane-5-carboxylic acid tert-butyl ester is as follows:

the structural formula of the 1-oxa-5-azaspiro [2,5] octane-5-methyl formate is as follows:

the additives have both epoxy and amide groups. That is, grafting of the first active group onto the carbon black body can be achieved by the above-mentioned additives.

Compared with the conventional carbon black, the silicon carbon black contains silicon element, so that the silicon carbon black has stronger affinity with a mother glass substrate and can be better dispersed on the substrate.

The surface of the silicon carbon black contains abundant reactive groups, and the reactivity of the silicon carbon black is mainly from oxygen-containing functional groups, such as carboxyl, hydroxyl, ketone and aldehyde, and the oxygen-containing functional groups endow the silicon carbon black with reactivity with other substances.

The heat stabilizer is used for preventing the epoxy group and the carbon black surface from being excessively oxidized and thermally degraded in a high-temperature calcination stage. The heat stabilizer has the general formula M (COOR)₂Wherein M is cadmium, barium, calcium, zinc, magnesium or strontium, R is long-chain saturated alkyl and has a general formula of C_nH_2n+1And n has a value of 1 to 6.

The function of the thermal dispersant is to ensure that the reaction system is heated more uniformly and the reaction is uniform. The thermal dispersant comprises polyvinylpyrrolidone.

The grinding aid has the function of enabling the particle size of the target product, namely the composite carbon black, to be smaller. The grinding aid includes metal inorganic salts, such as calcium carbonate.

S12, uniformly mixing the silicon carbon black, the additive and the thermal dispersant, heating and refluxing for 6-10 h at 80-150 ℃, taking out, washing with absolute ethyl alcohol, filtering and drying to obtain a first product.

S13, dispersing the thermal dispersant and the first product in the thermal dispersant, slowly heating to 300-400 ℃ for 1-3h, and slowly cooling to room temperature to obtain a second product.

Specifically, during the temperature rise, the temperature is raised to 150-200 ℃ at a speed of 10 ℃/min and is kept for 1h, and then the temperature is raised to 300-400 ℃. Carrying out pyrolysis at the temperature of 300-400 ℃ to obtain the composite carbon black.

And during temperature reduction, the temperature is reduced to 50 ℃ and kept for 1h, and then the second product is obtained after cooling to room temperature and separation.

And S14, adding the grinding aid into the second product, and crushing, grinding, ball-milling and sieving to obtain the composite carbon black.

The composite carbon black obtained at this time includes a carbon black main body and a first active group grafted to the carbon black main body.

Further, the preparation step of the composite carbon black also comprises the following steps:

and S15, immersing the composite carbon black in strong acid, stirring continuously, heating to 100 ℃, preserving heat for 3-5h, and filtering to obtain the acidic composite carbon black.

Wherein the stirring is performed for activating the carboxyl groups on the surface of the carbon black body.

S16, immediately using ammonia water to adjust the pH value of the acidic composite carbon black to be neutral, then adding the acidic composite carbon black into ethyl acetate and petroleum ether with the volume ratio of 1:15, and obtaining the improved composite carbon black through filtering, ball milling and sieving.

The purpose of using ammonia water immediately is to add ammonia water while it is hot, and to cause the ammonia water to perform an amide reaction with carboxyl groups on the surface of the carbon black main body, thereby generating an amide group. The composite carbon black obtained in this case includes a carbon black main body, a first active group, and a second active group.

That is, the first active group is grafted to the carbon black body by a physicochemical reaction between the additive and the carbon black body, and the second active group is obtained by an amide reaction between ammonia water and a carboxyl group on the carbon black body.

The inventors of the present application performed Fourier transform infrared detection on the composite carbon black, the additive and a commonly commercially available carbon black in the present application, and obtained an FT-IR spectrum as shown in FIG. 4. Wherein the maps (a), (b) and (c) respectively represent maps of the carbon black, the composite carbon black and the additive.

As can be seen from FIG. 4, the carbon black, the composite carbon black and the additive were all 3211cm in size^-1Has a broad peak caused by the stretching vibration of-OH, namely, the three contain abundant-OH. In addition, the spectrum of the composite carbon black and the additive is 2085cm^-1Has a strong peak at 1572cm due to epoxidation^-1Has a strong peak due to-N-H bond, and is at 1643cm^-1Peaks due to stretching vibration of the amide groups.

From the above analysis, it was found that a composite carbon black was successfully obtained by attaching an epoxy group and an amide group to the surface of carbon black.

The invention also provides a negative photoresist which is prepared by using the composite carbon black as a pigment. Because the composite carbon black has self-dispersion capability, no carbon black dispersing agent needs to be additionally added when the negative photoresist is prepared, the addition types of raw materials and the dispersion time are reduced, and the preparation efficiency is improved. And the dispersion effect of the composite carbon black is good, so that the product reliability of the negative photoresist is improved, and the display quality of the TFT-LCD is improved.

The negative photoresist comprises the following components in percentage by mass: 8.5 to 10.5 percent of alkali soluble resin, 5.0 to 8.0 percent of composite carbon black, 5.6 to 11.0 percent of monomer, 1.0 to 3.0 percent of oligomer monomer, 0.1 to 0.3 percent of photoinitiator and 75.0 to 83.0 percent of solvent.

The composite carbon black is the composite carbon black with self-dispersion capability in the application. Wherein, the epoxy group of the composite carbon black is easy to dissolve in the alkali soluble resin, so that the composite carbon black is easy to dissolve in the alkali soluble resin.

The alkali-soluble resin is prepared by carrying out reduced pressure heating and gradient elution treatment on 13-18% of methacrylic acid, 17-23% of methyl methacrylate, 20-28% of butyl methacrylate, 17-23% of benzyl methacrylate, 1-3% of hydrogen donor reagent, 7-10% of excess heat initiator and 25-40% of solvent according to the mass percentage.

The monomer includes at least one of methacrylic acid, butyl methacrylate and benzyl methacrylate. The monomer is used to change the solubility of the negative photoresist during development by cross-linking to form a network, while also affecting the sensitivity of the negative photoresist to light. The photoinitiator generates active free radicals after being irradiated by light, and then the monomer generates a crosslinking reaction, wherein the lower the potential energy barrier of the monomer is, the higher the activity is, and the higher the light sensitivity of the photoresist is.

The oligomer monomer serves to reinforce the crosslinked network formed by the monomer. The oligomer monomer is an oligomer of methacrylic acid and methyl methacrylate, and has a molecular weight of about 1000-2000.

The photoinitiator is used for absorbing energy in light to generate active fragments to initiate photopolymerization. The photoinitiator comprises one or more of acetophenones, alpha-aminoalkylbenzophenones, benzophenones, benzoins, thioxanthones, anthraquinones, triazines and oximes, such as: at least one of 2, 2-dimethoxy-2-phenylacetophenone, 2-diethoxy-acetophenone, 2-dibutoxyacetophenone, 1-hydroxy-cyclohexyl-phenyl ketone (184), 2-methyl-1- (4-methylthiophenyl) -2-morpholine-1-one (907) and 2-hydroxy-2-methyl-1-phenyl-1-one (1173) is illustrated.

The solvent is used for adjusting the viscosity and the leveling property of the negative photoresist and the saturated vapor pressure of a system. The solvent comprises at least one of Propylene Glycol Methyl Ether Acetate (PGMEA), propylene glycol ethyl ether acetate, diethylene glycol butyl ether acetate, 3-methoxybutyl acetate, methyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, and amyl formate.

Referring to fig. 5, a schematic diagram illustrating the dispersibility of common commercially available carbon black and the composite carbon black of the present application in alkali-soluble resins and resin monomers or oligomers is shown, and it can be seen from the schematic diagram that the composite carbon black particles have a size of 5-10nm, and are uniformly dispersed among the composite carbon black particles, and no aggregation occurs, i.e. the composite carbon black of the present application has a good dispersibility.

Referring to fig. 6, the present invention also provides a method for preparing a negative photoresist, comprising the steps of:

s21, weighing 8.5-10.5% of alkali soluble resin, 5.0-8.0% of composite carbon black, 5.6-11.0% of monomer, 1.0-3.0% of oligomer monomer, 0.1-0.3% of photoinitiator and 75.0-83.0% of solvent according to mass fraction percentage.

S22, adding the soluble resin, the monomer, the oligomer monomer and the composite carbon black into a stainless steel cylinder which is completely light-tight and sealed, and fully stirring and uniformly mixing to obtain a mixture A.

S23, adding the photoinitiator and the solvent into a stainless steel cylinder which is completely light-tight and sealed, and fully stirring and uniformly mixing to obtain a mixture B.

S24, simultaneously adding the mixture A and the mixture B into a completely sealed and lightproof stainless steel cylinder, and fully and uniformly stirring to obtain the negative photoresist.

According to the preparation method of the negative photoresist in the embodiment, no carbon black dispersing agent is additionally added, so that the addition variety of raw materials is reduced, the dispersing time is also reduced, the cost is saved, and the preparation efficiency is improved. And the dispersion effect of the composite carbon black is better, so that the product reliability of the negative photoresist is higher.

The inventor of the application takes the composite carbon black in the application as a raw material, prepares the negative photoresist by the method, and detects the dispersibility of the composite carbon black in the negative photoresist by a Transmission Electron Microscope (TEM). In which figure 7 shows a TEM spectrum of a negative photoresist in the present application. As can be seen from the figure, the particle size of the composite carbon black is less than 10nm, and the composite carbon black is uniformly dispersed in a negative photoresist system and has good compatibility.

The inventors of the present application also performed the measurement of optical density values (OD values) of different film thicknesses after spin coating the above negative photoresist on glass. Specifically, firstly, the negative photoresist prepared by using the composite carbon black is coated on glass in a spinning mode, and is pre-baked for 100s at 100 ℃, then, the glass is cooled to room temperature, and then, the amount of each drop of the negative photoresist and the spinning speed are controlled, so that wet films with a series of thicknesses are obtained. Then use 40mj/cm under Msak²Exposing, spray developing with 0.042% KOH developer, and developingCleaning with ultrapure water, and baking at 200-250 deg.C for 30min to obtain dry films with thicknesses of 0.982 μm, 1.011 μm and 1.039 μm.

Referring to fig. 8, which shows a TEM image of one of the dry films, it can be known that the dry film pattern is excellent in flatness, the entire profile of the pattern is free from defects, and the obtained pattern is clearly visible.

Referring to fig. 9, optical density values (OD values) at three dry film thicknesses are shown, wherein the OD value of the dry film with a thickness of 0.982 μm is 4.015, the OD value of the dry film with a thickness of 1.011 μm is 4.106, and the OD value of the dry film with a thickness of 1.039 μm is 4.202. The three data are plotted to obtain a curve, i.e., a linear equation of the OD VS film thickness in the graph. From this linear equation, it can be seen that the light-shielding density OD value is 4.01 when the film thickness is 1.00 μm, i.e., the negative photoresist of the present application has excellent light-shielding properties.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

It will be understood that the invention is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof.

Claims

1. The composite carbon black is characterized by comprising a carbon black main body and at least one first active group grafted on the carbon black main body, wherein the first active group simultaneously has an epoxy group and an amide group.

2. The composite carbon black of claim 1, further comprising at least one second reactive group grafted to said carbon black body, said second reactive group comprising an amide group.

3. The preparation method of the composite carbon black is characterized by comprising the following steps:

4. The method for preparing composite carbon black according to claim 3, further comprising the steps of:

5. The method for producing composite carbon black according to claim 3, wherein the additive comprises at least one of tert-butyl (3- (oxiran-2-yl) propyl) carbamate, tert-butyl 1-oxa-5-azaspiro [2,5] octane-5-carboxylate, and methyl 1-oxa-5-azaspiro [2,5] octane-5-carboxylate.

6. The method of claim 3, wherein said thermal stabilizer has the formula M (COOR)₂Wherein M is cadmium, barium, calcium, zinc, magnesium or strontium, R is long-chain saturated alkyl and has a general formula of C_nH_2n+1And n has a value of 1 to 6.

7. The method for preparing composite carbon black according to claim 3, wherein the grinding aid comprises a metal inorganic salt;

the thermal dispersant comprises polyvinylpyrrolidone.

8. A negative photoresist is characterized by comprising the following components in percentage by mass: 8.5 to 10.5 percent of alkali soluble resin, 5.0 to 8.0 percent of the composite carbon black of any one of claims 1 to 7, 5.6 to 11.0 percent of monomer, 1.0 to 3.0 percent of oligomer monomer, 0.1 to 0.3 percent of photoinitiator and 75.0 to 83.0 percent of solvent.

9. The negative photoresist of claim 8, wherein the alkali-soluble resin is prepared by subjecting 13-18% of methacrylic acid, 17-23% of methyl methacrylate, 20-28% of butyl methacrylate, 17-23% of benzyl methacrylate, 1-3% of hydrogen donor agent, 7-10% of excess heat initiator and 25-40% of solvent to reduced pressure heating and gradient elution.

10. A method for preparing a negative photoresist is characterized by comprising the following steps:

weighing 8.5-10.5% of alkali soluble resin, 5.0-8.0% of the composite carbon black as claimed in any one of claims 1-7, 5.6-11.0% of monomer, 1.0-3.0% of oligomer monomer, 0.1-0.3% of photoinitiator and 75.0-83.0% of solvent according to mass fraction percentage;