CN111205736A - Anti-radiation heat dissipation coating composition containing barite powder - Google Patents

Abstract

The invention provides a radiation-proof heat-dissipation coating composition containing barite powder, which comprises barite powder, wherein the barite powder is prepared by a method comprising the following steps: in the presence of a polymer dispersant, grinding a barite raw material to obtain barite powder. Through the use of the polymer dispersant, the prepared barite powder has excellent fine granularity and very high dispersity, and has good dispersity when used for a coating, so that the radiation-proof and heat-dissipation effects of the coating can be remarkably improved.

Description

Anti-radiation heat dissipation coating composition containing barite powder

Technical Field

The invention belongs to the technical field of coatings, and relates to a radiation-proof heat dissipation coating composition, in particular to a radiation-proof heat dissipation coating composition containing barite powder.

Background

Radiation protective coatings are a class of materials that are capable of absorbing electromagnetic wave energy that is transmitted to their surface and converting into thermal energy through the loss of the material. Among various electromagnetic radiation protective materials, paints are attracting attention for their many advantages of convenience, light weight, space saving, and integration with substrates. The radiation-proof coating can absorb redundant electromagnetic waves, so that the interference of clutter on self equipment can be reduced, the disturbance and the injury of electromagnetic radiation on surrounding equipment and personnel can be effectively prevented, and the radiation-proof coating is convenient to coat, so that the radiation-proof coating can be used for various equipment and different parts of the equipment.

The radiation-proof barium sulfate is a material with good protection to high-energy rays, and has the advantages of low cost, convenient construction, long service life and the like. The barite has barium sulfate as main component and X-ray absorbing performance, and may be used in making paint to replace lead plate in shielding radiation. The barite also has the advantage of good heat conductivity, so the barite has good prospects when being used for paint preparation.

The natural barite has the characteristics of high density, low hardness, brittleness and the like, is stable in chemical property, non-magnetic and non-toxic, can absorb rays and rays, and has been widely applied to industries such as petroleum drilling, rubber, coating, plastics, papermaking and the like as a filler. China is a big country for producing the barite, and the annual output and the export amount are more than ten thousand tons and account for 60 percent of the total export amount of the world. At present, the demand of the barite at home and abroad is on the rising trend, and the resource is seriously insufficient, which brings excellent opportunity for the barite industry in China. However, at the present stage, the barite is mainly produced by rough processing, and a few enterprises begin to process the ultrafine powder, but the overall processing technology falls behind, the added value of the product is low, the excellent functions of the barite are not deeply developed, so that the resource advantages cannot form the industrial and economic advantages, and the reasonable utilization of the resources is seriously wasted. Therefore, the deep processing technology of barite minerals faces good market opportunities and new challenges. How to face such opportunities and challenges, in addition to the ever increasing quality and functionality of technical products according to the changing market and application requirements, must rely on the intervention of new technologies.

CN107858086A discloses a radiation-proof interior wall coating, which comprises: 2-5 wt% of graphene composite flower-like bismuth tungstate, 4-5 wt% of wolframite powder, 5-10 wt% of titanium dioxide, 40-50 wt% of aqueous polyurethane resin, 15-25 wt% of silica sol, 2-3 wt% of ethylene glycol, 5-10 wt% of tin-plated barium sulfate waste residue, 0.5-2 wt% of anti-aging agent, 1-2 wt% of flatting agent, 0.5-1 wt% of dispersing agent, 1-2 wt% of defoaming agent and 0.5-2 wt% of film-forming assistant.

CN105820604B discloses an environment-friendly radiation-proof paint, which takes barium sulfate or barite as a main material, takes metallic iron or derivatives thereof, copper or derivatives thereof, tin or derivatives thereof, bismuth or derivatives thereof, tungsten or derivatives thereof and rare earth elements or derivatives thereof as auxiliary materials, and takes polymer glue powder as a bonding agent, wherein the polymer glue powder is selected from 901 polymer glue powder, 801 polymer glue powder, 107 polymer glue powder or M40 polymer glue powder, and the polymer glue powder accounts for 0.2-0.8% of the total mass of the paint.

CN110003695A discloses a radiation-proof paint, which comprises the following raw materials in parts by weight: 10-20 parts of magnesium lithium silicate, 50-60 parts of barite, 10-20 parts of oyster shell, 10-20 parts of activated carbon, 20-30 parts of inorganic gelling agent, 20-30 parts of organic adhesive, 1-5 parts of concentrated sulfuric acid and 50-100 parts of distilled water.

CN110229578A discloses a radiation-proof water-based paint, which comprises the following raw materials in parts by weight: 10-15 parts of polyurethane emulsion, 50-60 parts of water-based acrylic emulsion, 0.1-0.5 part of defoaming agent, 5-10 parts of film-forming assistant, 0.3-0.5 part of base material wetting agent, 5-10 parts of deionized water, 0.1-0.5 part of flatting agent, 0.5-1.0 part of thickening agent and 3-8 parts of radiation-proof assistant.

CN1884087A discloses a method for preparing nano barite, comprising the following steps: A. sanding the zirconia beads and the natural barite in a sand mill; B. uniformly dispersing the product obtained in the step A in water, and adding polyphosphate anionic dispersing agent or sodium hexametaphosphate to prepare a solution; C. and D, sanding the product obtained in the step B in a sand mill, and performing filter pressing.

CN101012342A discloses a modified barite, a wrapping material is arranged outside barite particles, the wrapping material contains titanium dioxide, and a method for preparing the modified barite is also provided, wherein the surface modification is carried out by adopting an organic hybridization technology of titanium wrapping or aluminum-titanium wrapping nano barite, so that the prepared nano barite has the same material with nano titanium dioxide.

CN102127318A discloses barite powder for oil and gas field drilling fluid and a modification method thereof. Spraying a mist chemical chelating activator on the surface of the barite powder, wherein the spraying amount of the chemical chelating activator is 0.3-0.6% of the weight of the barite powder; wherein, the proportion (weight percentage) of the chemical chelating activator is as follows: 3-5% of sodium dodecyl sulfate, 5-10% of octyl phenol polyoxyethylene ether-10, 5-8% of aluminum lignosulfonate and the balance of water; the powder fineness of the barite powder is 200-300 meshes.

CN102616824A discloses a preparation method of ultrafine high-whiteness active barite powder, which comprises the following steps: mixing 325-mesh barite powder into ore pulp, and carrying out wet superfine grinding until the particle size is less than 10 mu m; filtering and drying the barite slurry after wet superfine treatment; adding mixed acid into the dried superfine barite powder, and carrying out stirring oxidation leaching reaction treatment, wherein the mixed acid is a mixed solution of sulfuric acid, hydrofluoric acid and oxalic acid; filtering and washing the barite powder subjected to the oxidation leaching reaction of the mixed acid to the pH value of 6-7; filter pressing and drying to obtain the ultrafine high-whiteness active barite powder.

CN109127081A discloses a barite production method, including the barite material, the barite feed, break up breakage, material grinding, calculate reinforced, mixing stirring, dehydration drying, selecting materials are collected, are washed and selected, whiten and the shaping is stored, through setting up mixing stirring and replacing manual stirring can the material between the more even of mixing.

CN108002420A discloses a production process for whitening barite powder, which comprises the following steps: adding borax and sodium hydroxide into the barite powder, and roasting in a roasting furnace; feeding the roasted material into a wet type fine grinding machine for grinding; feeding the slurry from the wet type fine grinding machine into a reaction kettle, adding concentrated hydrochloric acid, and reacting in the reaction kettle; the reacted materials are treated by the conventional processes of filtering deacidification, stirring washing, filtering and drying to obtain fine barite powder.

"research progress and problems existing in the preparation technology of radiation-proof concrete", royal jelly and the like, new technology and engineering application of special concrete and asphalt concrete, 2012, the research progress of radiation-proof concrete at home and abroad from the perspective of raw materials and preparation technology of radiation-proof concrete, the application of main raw materials by contrast, and some problems existing in radiation-proof concrete at present from the aspects of raw materials, mix proportion design, long-term performance and the like of radiation-proof concrete.

The research on the nuclear radiation resistance of the coating, the research on the salix sensitivity and the like, the coating industry, 4 months in 2013, researches the irradiation effect of 2 coating samples irradiated by 60Co gamma rays at room temperature in the air atmosphere, adopts a Fourier infrared analyzer (FTIR) to analyze the components and the structural changes of the samples before and after irradiation, and screens out groups with relatively stable structures under the nuclear irradiation condition.

However, in the prior art, the dispersion of the barite powder in the paint is poor, especially for some high-demand applications, which severely limits the application range, and when the dispersion is insufficient, besides causing the performance of the paint to be unstable, a serious problem is that the radiation protection performance is seriously weakened, for example, the weak part of the barite powder with less distribution has poor radiation protection performance, and the uneven barite powder in the paint also causes errors and misjudgment of the detection of the radiation protection performance. In order to improve the dispersibility of the barite, a dispersant is generally added to solve the problem, but a general conventional dispersant is lack of pertinence and has poor effect on dispersing the barite powder, and even though the dispersant is added to a certain extent, the problem of dispersing the barite powder can be solved, the use amount of the dispersant is large, and a high amount of the dispersant causes many undesirable problems.

Therefore, there is a need in the art for a radiation protective and heat dissipating coating capable of uniformly dispersing the contained barite powder, wherein the dispersion of the barite can be effectively improved without using a dispersant or using a low amount of the dispersant.

Disclosure of Invention

In order to solve the above technical problems, the present inventors have made extensive and systematic studies and, through extensive experiments and cooperative research and development, have provided the following technical solutions.

In one aspect of the invention, a radiation-proof heat-dissipation coating composition containing barite powder is provided, which comprises barite powder, wherein the barite powder is prepared by a method comprising the following steps: in the presence of a polymer dispersant, grinding a barite raw material to obtain barite powder.

Preferably, the coating is a solvent-based coating or a non-solvent-based coating.

Preferably, the coating may be a mortar coating.

Preferably, the radiation-proof heat dissipation coating is a powder coating.

Preferably, the raw material of the coating comprises a resin or polyester component.

Preferably, the barite powder has an average particle size of less than about 150 nm.

In a preferred embodiment of the present invention, the radiation protective and heat dissipating coating further comprises a metal oxide. More preferably, the oxide is lead oxide.

For the purposes of the present invention, the particle size of the metal oxide is preferably from about 20 to 100 mesh.

Preferably, the specific surface area of the barite powder is about 20-60m²/g。

Preferably, the crystal form of the barite powder is simple rhombus.

In another aspect of the invention, a method for preparing the radiation-proof heat dissipation coating composition comprises mixing barite powder and ingredients.

When the coating is radiation-protective and solvent-borne, the coating comprises: the barite powder, the epoxy resin, the polyacrylate, the diluent and the curing agent; wherein, based on the total weight of the coating, the content of the barite powder is 10-30%, the content of the epoxy resin is 30-50%, the content of the polyacrylate is 10% -20%, the content of the diluent is 10-20%, and the content of the curing agent is 5-10%.

The diluent and curing agent are not critical and may be additives as are common in the art. One skilled in the art will also recognize that other conventional additive ingredients may be included in the coating depending on the particular application, such as film formers, pigments, fillers, leveling agents, and the like. It is also known to those skilled in the art that the epoxy resins, polyacrylates also include epoxy resins, polyacrylates in emulsion form.

Additionally or alternatively, when the coating is a radiation protection mortar coating, it comprises: aggregate, cement, and the barite powder. Preferably, the radiation-proof mortar coating further comprises one or more additives selected from the group consisting of a water reducing agent, a thickener and an antifoaming agent.

Preferably, the barite powder accounts for 10-30% of the total weight of the radiation-proof mortar coating. When the content of the barite powder is too low, the radiation protection performance may not be satisfactory, and when the content is too high, the strength performance of the coating may be weakened.

The specific selection and amounts of the other ingredients are not particularly critical and are selected from those conventional in the art, for example, as will be appreciated by those skilled in the art, the aggregate may be sand, the cement may be portland cement, and sometimes the mortar coating may also include water when in use.

The additive can increase the density of the mortar coating without substantially impeding its setting and without entraining significant amounts of air. The defoamer mixture is suitable for reducing the air content and increasing the density of the mortar or concrete. The thickener mixture is suitable for inhibiting the exudation of water from mortar or cement.

The barite powder is preferably prepared by a method comprising the following steps: in the presence of a polymer dispersant, grinding a barite raw material to obtain barite powder.

Preferably, the grinding is performed by wet grinding.

The grinding may be carried out by a grinding apparatus such as a planetary ball mill or a stirring mill.

The barium sulfate content of the barite feedstock is greater than 90 wt.%, preferably greater than 95 wt.%, more preferably greater than 98 wt.%, in terms of purity of the barite feedstock.

Preferably, grinding media are also used in the grinding process.

Preferably, the milling is wet milling. The milling media is preferably water, ethanol or a mixture thereof, more preferably a mixture of water and ethanol, preferably in a volume ratio of water to ethanol of 10:1 to 5: 1.

In the milling, the amount of milling media is preferably 20-80 wt.%, more preferably 30-60 wt.%, based on the barite feedstock. The amount of dispersant is preferably 0.1-2.0 wt.%, more preferably 0.2-1.0 wt.%, based on the barite raw material.

Preferably, the grinding comprises: adding the barite raw material and a grinding medium into a grinding device, mixing, grinding for 2-5 minutes, adding a dispersing agent, and continuously grinding for 30-60 minutes.

When planetary ball milling or stirring milling is used, the rotation speed is preferably 200-.

In a particularly preferred embodiment, the polymeric dispersant is a polymeric dispersant of the following formula (I):

the number average molecular weight of the polymer is 5000-; m/n is 1:5 to 5:1, preferably 1:2 to 2: 1.

The polymer shown in the formula (I) is a block polymer. The polymer dispersant shown in the formula (I) is prepared by polymerizing poly 4-vinylpyridine and 2-vinyl monomer. The method comprises the following specific steps: under the protection of nitrogen, adding poly 4-vinylpyridine and 2-vinylpyridine monomers into a DMF (preferably, the volume ratio of the 2-vinylpyridine monomer to DMF is 3:1, the molar ratio of the vinylpyridine part in the poly 4-vinylpyridine to the 2-vinyl monomer is 1:5-5:1, preferably 1:2-2:1), using azoisobutyronitrile as an initiator, and reacting at the temperature of 50-70 ℃ for 20-60 min. Preferably, the polymerization is carried out in bulk.

One skilled in the art will recognize that azoisobutyronitrile may be added in an amount effective to initiate polymerization.

The poly-4-vinylpyridine is prepared by using azoisobutyronitrile as an initiator and taking the dithiobenzoic acid cumyl ester as a reversible fragmentation addition chain transfer agent to perform reversible fragmentation addition chain transfer reaction on a 4-vinylpyridine monomer. Preferably, the reaction is synthesized under bulk conditions. Preferably, the reaction is protected with nitrogen, and the reaction temperature is preferably about 60 ℃. Particularly preferably, the molar ratio of azoisobutyronitrile to cumyl dithiobenzoate is 1:4.5, and the initial monomer concentration is 9.00M (bulk monomer). Preferably, the molar ratio of the dithiobenzoic acid cumyl ester to the 4-vinylpyridine monomer is 1: 375. Preferably, the number average molecular weight of the poly-4-vinylpyridine is 2000-20000 g/mol.

In the wet-milled state, the presence of the polymeric dispersant, i.e., the dispersion medium, effectively prevents direct contact of the particles, thereby reducing the effects of van der waals forces between the particles. When the dispersing agent is added, the dispersing agent can penetrate into cracks of crystals very effectively to accelerate the thinning of particles, and the crushed crystals are kept for a certain distance due to the addition of the dispersing agent so as not to collide and agglomerate. The dispersant has affinity action for water, and can prevent electrostatic action of an electric double layer and massive generation of a fluxed film. Therefore, when the dispersant was used, the time of the grinding equilibrium was significantly delayed and the particle size was finer than other samples, compared to conventional dispersants such as abrasives of ethanol, polyamino salts, polyacrylic acid derivatives, polyether derivatives, etc., for example, the time of the grinding equilibrium was delayed by 20% and the particle size fineness was improved by 30% compared to sodium polyacrylate. Compared with ethanol as a dispersing agent, ethanol has the double functions of suspension and dispersing agent, so the grinding efficiency is higher, but after being crushed to a certain degree, a thicker protective film is easily formed on the surface of the crystal, so that a grinding medium cannot impact the crystal and can only slide on the film, the grinding efficiency is reduced quickly, and the start time of reverse grinding is obviously earlier.

In a preferred embodiment of the invention, the barite powder obtained after milling has an average particle size of less than about 150nm, preferably less than about 120nm, more preferably about 100 nm. The inventors found that although it is generally considered that the smaller the average particle size of the barite powder is, the better, the inventors studied and found that if the particle size of the barite powder is too small, on the one hand, the process cost is increased because it requires a higher intensity grinding device and longer grinding time, and on the other hand, the too small particle size is not the best dispersion in the paint, and secondary aggregation of a plurality of particles occurs in the solution during the paint production process, which adversely affects the performance.

Preferably, the particle size distribution of the barite powder has a D of about 80-120nm₉₀D less than about 30nm₁₀。

Preferably, D₉₀/D₁₀The ratio of (A) to (B) is about 4.0 to 5.0. The inventors have found that when D is used₉₀/D₁₀When the ratio is within this range, i.e., when the two particle size distribution ratios are adopted, the coating composition has particularly good properties for coating applications. Smaller nanoparticles can be filled in gaps among larger particles, so that slurry with high solid content and low viscosity can be obtained, higher filler strength is provided, and pigment particles can stably exist in a suspended state.

Preferably, the specific surface area of the barite powder is about 20-60m²/g。

For the purposes of the present invention, the crystal form of the barite powder is preferably simple rhombohedral.

In another aspect of the present invention, the present invention provides a highly dispersed barite prepared by the above preparation method.

The high-fraction barite can be used for preparing coatings.

The barite powder prepared by adding the dispersant has excellent fine particle size and very high dispersibility, and has the advantages of good dispersibility, high stability, high whiteness and the like when used for coating. As with other powders, the barite powder raw material contains inevitable impurities, and among them, colored impurities such as pyrite, clay minerals, manganese-containing minerals, and the like are mixed in the gaps of the barite crystals in a substantially fine-grained monomineral form. Therefore, in order to remove these colored impurities, it is first required to process and pulverize the powder as finely as possible. In the present invention, the barite powder can be ground particularly finely and aggregation can be avoided to a limited extent due to the use of the dispersant, thereby enabling the impurities to be removed very efficiently, resulting in a particularly high whiteness of the barite powder. The higher whiteness allows the barite to replace titanium dioxide in a certain proportion when used in coating applications.

It will be appreciated by those skilled in the art that the removal of impurities may be carried out by conventional methods, such as chemical bleaching.

The barite powder prepared by the method is enough for general application requirements, namely the purpose of the invention. For the application of special high-grade paint, such as pigment and automobile paint with high requirement on paint stability, the surface of the barite powder can be preferably modified, the stability of the barite powder can be obviously improved through modification, the interaction with other components of the paint can be effectively avoided in the using process, the physical and chemical properties of the surface of the barite powder can be improved, the compatibility with resin in the paint and the dispersibility in an organic matrix can be enhanced, the shielding performance of the powder paint on radiation can be improved, and the glossiness and the comprehensive performance of the powder paint can be improved. Thus, the skilled person will appreciate that for the purposes of the present invention, this surface modification step is not a necessary or essential step, but an optional step that may be selected.

In the invention, the surface of the natural barite powder can be chemically modified, so that the sedimentation speed of the natural barite powder in the coating is reduced, the dispersibility is improved, and the surface of the natural barite powder has good hydrophobicity, so that the water resistance is improved, and the weather resistance is further improved.

In a preferred embodiment, the surface of the particles of the barite powder is chemically coating modified with an organosilicon compound.

In the present invention, it is preferable to carry out the modification by dispersing the barite powder in an organic solvent (preferably glacial acetic acid) in a reaction vessel and adding an organic silicon compound as a surface modifier, carrying out ultrasonic treatment, then leaving the colloidal suspension for 12 to 36 hours, preferably 24 hours, then diluting the colloidal suspension with acetone, further ultrasonic treatment, then filtering, washing with acetone, and drying to obtain the surface-modified barite powder.

The organic solvent is used in an amount that enables the barite powder particles to be effectively dispersed.

Preferably, the weight ratio of organosilicon compound to barite powder is 1.0-10 wt.%.

The staged sonication and placement (i.e., standing) can cause condensation of the organosilicon compound on the surface of the barite nanoparticles.

More preferably, the organosilicon compound is a compound represented by the following formula (II):

when the compound is used for carrying out surface modification on the barite powder particles, alkoxy in the compound reacts with hydroxyl on the surfaces of the barite powder particles to be fixed on the surfaces of the particles, a hydrophobic surface monomolecular layer is formed, and the water resistance of the compound is greatly improved. The barite powders before and after modification were subjected to solid tableting, and it was found that the interfacial contact angle of the modified solid tableting was increased from about 27 to 120 or more.

Preferably, the compound of formula (II) can be prepared, for example, by the following method: in a reaction vessel, thiacalixarene tetraacid was added to SOCl₂Middle (thiacalixarene tetra-acid with SOCl)₂The molar ratio is 1:4-1:6), refluxing for 1-3 hours, and then adding the mixture containing the alcohol and SOCl₂Refluxing the mixture for 12-36 hours in a solution of substantially equimolar amounts of 3-aminopropyltriethoxysilane and triethylamine in THF, evaporating the solvent in vacuo, dissolving the residue in diethyl ether, filtering and evaporating to obtain the compound of formula (II). Its melting point is about 220 ℃. The method has the advantages of few synthesis steps and high product purity, and the product purity can reach about 98%. The modification method or the modification process comprises the following steps: dispersing barite powder in glacial acetic acid in a round-bottom flask, adding an organic silicon compound shown in formula (II) as a surface modifier according to the proportion, performing ultrasonic treatment (for example, 30min), standing a colloid suspension (for example, 24 h), diluting the colloid suspension with acetone, further performing ultrasonic treatment (for example, 60min), filtering, washing with acetone, and drying to obtain the surface-modified barite powder.

The dispersion of the barite nano-particles subjected to surface modification by the compound in the colloidal suspension is improved, and due to the hydrophobic structure of the particle surface, the water resistance of the coating and the adhesion with other components in the coating can be remarkably improved when the barite nano-particles are used as coating components, and the surface of the coating is smooth after the coating is formed, so that the barite nano-particles have better hand feeling. Presumably, the cup-shaped aromatic group provides particularly good hydrophobic properties. The cup-shaped structure can also contain other small molecular components in the coating, so that a particularly good complex is formed, the hydrophobic effect can be achieved, and the compatibility is particularly good. When used in coatings, the surface modification can have good thermal stability and higher solvent (e.g., alcohol) resistance, and the steric hindrance of the silicone surface modifier can effectively reduce polymerization between particles, thereby further enhancing dispersibility and stability. When the coating is used for radiation-proof heat dissipation coatings, good effects can be expected. Because the application environment of the radiation-proof heat-dissipation coating is generally severe, compared with unmodified barite nanoparticles, the surface-modified barite nanoparticles have higher thermal stability, and the heat-conducting property of the cup-shaped structure is also improved.

Drawings

FIG. 1 is a TEM image of barite powder particles surface-modified with a compound of formula (II) according to the method of the present invention;

fig. 2 is a TEM image of barite powder particles without surface modification.

Detailed Description

The following are specific examples illustrating the present invention, but the present invention is not limited thereto.

Example 1

100.5g of natural barite powder (from aptoa) are weighed out, dried in an oven at 110 ℃ for 45min, cooled to room temperature and placed in a high-speed mixer-agitator, after which grinding media, preferably a mixture of water and ethanol (5:1v/v), preferably in an amount of 40 wt.%, based on the barite raw material, and a dispersing agent, preferably in an amount of 0.1 wt.%, based on the barite raw material, are added, preferably by means of a planetary ball mill or stirred mill, preferably at a speed of 300r/min, for 40min, and dried to obtain the barite powder. Using AS-30Measuring specific surface area of powder with 12-type aperture and specific surface area analyzer, testing particle size and distribution of powder with Malvern 3000-type laser particle sizer, detecting that the average particle size of barite powder is 96nm, and specific surface area is about 57.2m²/g。

Further removing impurities from the ground barite powder by using HCl (10 v%) -Na as a treating agent₂S₂O₃(Na₂S₂O₃3.0 wt.% of HCl solution), the reductive bleaching temperature was 100 ℃ for 1.0h, then dried and pulverized in a high-speed mixer-blender. The whiteness R (457) of the white glass measured by a WSB-CY type desktop intelligent fluorescent whiteness instrument is 92.1 percent.

Comparative example 1

Example 1 was repeated, differing from example 1 only in that the dispersant used was a commercially available sodium polyacrylate dispersant (available from Shandong Seno Fine chemical Co.). After grinding, the barite powder is detected to have the average grain diameter of 208nm and the specific surface area of about 27.7m²(ii) in terms of/g. After bleaching and impurity removal treatment, the whiteness R (457) is 80.1 percent.

It is clear from the above examples and comparative examples that, when the polymeric dispersants of the invention are used, finer powder particle sizes can be obtained under the same milling conditions and better whiteness after impurity removal treatment, so that when they are used in coatings, they have particularly good color properties.

Example 2

100 parts by weight of portland cement, 20 parts by weight of sand, 50 parts by weight of the impurity-removed barite powder prepared in example 1, 0.8 part by weight of a methylnaphthalenesulfonic acid formaldehyde condensate water reducing agent (available from north Huichi Hengjing chemical company), 80 parts by weight of water, and 0.2 part by weight of an antifoaming agent (Nopco PD-1 available from Hangao company) were added, mixed, coated on a substrate, and then cured for 28 days to ensure a cured thickness of about 20 mm. According to the method of GB 16363-.

Comparative example 2

Example 2 was repeated, differing from example 2 only in that the barite powder was replaced with the barite powder of comparative example 1. According to the method of GB 16363-.

It is clear from example 2 and comparative example 2 that the shielding rate of the coating against X-rays is significantly improved when the resulting barite powder is ground with the dispersant of the present invention. This may be due to the good dispersibility of the barite powder in the coating, with an overall improved radiation shielding of the coating, as analyzed before.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. All citations referred to herein are incorporated herein by reference to the extent that no inconsistency is made.

Claims (10)

1. The radiation-proof heat-dissipation coating composition containing barite powder comprises barite powder, wherein the barite powder is prepared by a method comprising the following steps: in the presence of a polymer dispersant, grinding a barite raw material to obtain barite powder.

2. The radiation protective and heat dissipating coating composition of claim 1, wherein the coating is a solvent borne coating.

3. The radiation protective and heat dissipating coating composition of claim 1, wherein the radiation protective and heat dissipating coating is a powder coating.

4. The radiation protective and heat dissipating coating composition of any of the preceding claims, wherein the raw materials of the coating comprise a resin component.

5. The radiation protective and heat dissipating coating composition of any of the preceding claims, wherein the barite powder has an average particle size of less than about 150 nm.

6. The radiation protective and heat dissipating coating composition of any of the preceding claims, wherein the radiation protective and heat dissipating coating further comprises a metal oxide.

7. The radiation protective and heat dissipating coating composition of claim 6, wherein the metal oxide has a particle size of about 20 to 100 mesh.

8. The radiation protective and heat dissipating coating composition of any of the preceding claims, wherein the barite powder has a specific surface area of about 20-60m²/g。

9. The radiation protection and heat dissipation coating composition as recited in any one of the preceding claims, wherein the crystal form of the barite powder is simple rhombohedral.

10. A method of making the radiation protective and heat dissipating coating composition of any of the preceding claims comprising mixing barite powder with the ingredients.

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