88 results about "Melamine formaldehyde" patented technology

The invention relates to the field of nano materials and electrochemical technology materials, in particular to a melamino-formaldehyde / MXene composite material, a derived carbon material thereof, a preparation method and application. According to the preparation method disclosed by the invention, MXene is taken as a substrate, and protonated melamine formaldehyde molecules are inserted into MXene layers through an electrostatic self-assembly effect, so that the melamine formaldehyde / MXene composite material is synthesized; and carrying out high-temperature calcination on the basis to prepare the melamine formaldehyde / MXene composite material derived carbon material. According to the invention, active sites for adsorption and catalytic conversion of iodine species are provided while self-stacking of MXene is solved, and the melamine formaldehyde / MXene composite material is used as the positive electrode material of the aqueous zinc-iodine battery, so that the iodine species can be effectively anchored, and the active sites for catalytic conversion of iodine are fully provided; the reversibility and the structural stability of the electrode reaction are enhanced, so that the electrochemical performance of the battery is greatly improved.

This invention discloses a method for preparing a nitrogen-doped titanium dioxide and carbon hollow sphere heterojunction photocatalyst, comprising the following steps: 1) preparing a carbon hollow sphere core-shell structure sample based on melamine-formaldehyde nanospheres; 2) preparing a TiO2@carbon core-shell structure sample using the carbon hollow sphere core-shell structure and tetrabutyl titanate as the reaction system; 3) using a one-step method to simultaneously dope nitrogen into the TiO2@carbon core-shell structure to form an N-TiO2@N-doped carbon hollow sphere heterojunction. This invention provides a method for preparing a nitrogen-doped titanium dioxide@carbon hollow sphere heterojunction photocatalyst and its application. This method achieves uniform nitrogen doping and effective composite of TiO2 and carbon hollow spheres through specific steps, and the prepared photocatalyst exhibits excellent photocatalytic performance under both visible and ultraviolet light.

The invention discloses a method for catalyzing melamino-formaldehyde resin methylation reaction by solid acid. According to the invention, epoxy silane coupling agent grafted modified nanocellulose is introduced into sulfonated styrene-divinyl benzene cross-linked copolymer microspheres for in-situ crystal cross-linking, so that the problems that the traditional sulfonated polystyrene resin is poor in mechanical strength and solution solubility resistance, low in cycle index, easy to swell and fall off and the like are effectively solved; the prepared solid acid resin has the characteristics of high reaction activity, high proton transfer rate, high mechanical strength, high cyclicity and easiness in solid-liquid separation, and by utilizing the solid acid resin to catalyze the etherification reaction of the melamino-formaldehyde resin, the reaction temperature and the production energy consumption are reduced, the reaction time is shortened, the product quality and the production efficiency are improved, and the production cost is reduced. The problems of environmental protection and energy consumption caused by the generation of a large amount of VOCs in the etherification reaction of the traditional liquid catalyst for synthesizing the high-etherified melamine formaldehyde resin and the by-product inorganic salt in the subsequent process are solved.

The invention discloses a thermochromic material cable and a preparation method thereof, and relates to the field of power equipment. A thermochromic material cable comprises at least one insulating wire core, an inner wrapping layer is wrapped outside the insulating wire core, a sheath layer is wrapped outside the inner wrapping layer, the insulating wire core sequentially comprises a conductor, a wire sheath and an insulating layer from inside to outside, and the sheath layer comprises the following raw materials in parts by weight: 140-210 parts of a sheath raw material; 1 to 2.2 parts of a thermochromic microcapsule; the raw material of the sheath adopts polyvinyl chloride resin as a base material; the thermochromic microcapsule selects modified melamine-formaldehyde-ethyl cellulose as a capsule wall material and a thermochromic material as a capsule core, the mass ratio of the capsule core to the capsule wall material is (2-2.5): 1, and the average particle size is 0.3-0.7 mu m. According to the thermochromic cable, the high temperature resistance and the ultraviolet resistance of the thermochromic material added into the cable can be improved, so that the thermochromic material cable can realize temperature detection and early warning discoloration for a long time.

The invention discloses a compound dispersing agent, a mixed electroplating solution and application, the compound dispersing agent comprises a first anionic surfactant, a second anionic surfactant and a nonionic surfactant, and the first anionic surfactant comprises a sulfonate compound; and / or the second anionic surfactant comprises one or more of betaine or carboxylate; and / or the nonionic surfactant comprises one or more of a naphthoquinone sulfonate formaldehyde condensation compound, a melamine-formaldehyde condensation compound and methylnaphthalene sulfonic acid formaldehyde condensation compound sodium salt. In the compound dispersant, the first anionic surfactant plays a role in surface wetting and dispersing, the second anionic surfactant plays a role in main dispersing, and the nonionic surfactant plays a role in surface active wetting, so that the compound dispersant disclosed by the invention has good synergism; the graphene dispersing agent plays a role in dispersing graphene in a plating solution system, plays a certain positive role in ion migration in the plating solution, and does not cause poisoning harm to the plating solution.

The invention belongs to the technical field of melamine resin preparation, and provides yellowing-resistant antioxidant melamine resin and a preparation method thereof. The preparation method comprises the following steps: firstly, by taking melamine, formaldehyde and a modifying reagent as raw materials, preparing a melamine prepolymer by adjusting reaction conditions; secondly, a quinone-phenol hybrid antioxidant is designed and prepared, and through introduction of a hybrid molecular structure, the quinone-phenol hybrid antioxidant has excellent free radical capture ability and oxidation inhibition effect; then, a multifunctional light stabilizer containing hindered amine, phosphine and triazine groups is synthesized, and the light stability and weather resistance of the material are remarkably improved by utilizing an intermolecular synergistic effect; and finally, uniformly dispersing and curing the melamine prepolymer, an antioxidant, a light stabilizer and other auxiliaries, and carrying out multi-step temperature regulation and curing treatment to prepare the melamine resin material with excellent performance.

The invention discloses a modified graphene enhanced MF sponge for oil-water separation and performance testing equipment thereof, belongs to the technical field of graphene reduction, and solves the problems of complex reduction process and high energy consumption of an rGO composite material in the prior art. The modified graphene enhanced MF sponge comprises a sponge bearing part and a modified graphene layer anchored on a porous structure of the sponge bearing part, modified graphene comprises rGO-ZnO and rGO-ZnO / ZIF-8, and the sponge bearing part is melamine formaldehyde sponge, also called melamine formaldehyde sponge. According to the modified graphene enhanced MF sponge, through a photocatalytic reduction strategy, collaborative optimization of a super-hydrophobic surface, high adsorption capacity, excellent mechanical strength and green preparation is achieved, and the prepared rGO-ZnO / ZIF-8-coated MF sponge not only has good oil adsorption performance, but also has photocatalytic performance, so that the sponge has excellent performance in the field of oil-water separation.

The invention discloses melamine formaldehyde resin and a production process thereof, and belongs to the technical field of high polymer materials. The production process comprises the following steps: carrying out a reaction on melamine and 2, 5-furandicarbonyl chloride to generate an intermediate, carrying out a condensation polymerization reaction on the intermediate, the melamine and formaldehyde, and adding a polyvinyl alcohol-metal complex for common condensation polymerization to form the melamine formaldehyde resin. 2, 5-furandicarbonyl chloride of a biological source is used for replacing part of formaldehyde, the content of methanol is reduced, meanwhile, a hydroxymethyl crosslinking site at one end of a furan ring can be closed, the crosslinking density is reduced, and the toughness is improved. Under the condition that the reaction energy is reduced by the metal ions, the polyvinyl alcohol and the formaldehyde are subjected to aldolization to block free formaldehyde; the coordination effect of metal ions and furan rings further promotes the crosslinking of polyvinyl alcohol and melamino-formaldehyde molecular chains, and the flexible long chain of the introduced polyvinyl alcohol reduces the brittleness of the resin material.

The invention discloses an organic-inorganic multi-component hybrid phase change microcapsule energy storage material and a preparation method thereof, and relates to the technical field of phase change energy storage materials. The energy storage material comprises a multi-component organic phase change core material and an organic-inorganic multi-component hybrid shell material, the multi-component organic phase change core material is composed of PEG4000, PEG6000, lauric acid and Span-80 according to specific parts by mass, the organic-inorganic multi-component hybrid shell material is composed of a melamine-formaldehyde prepolymer, nano modified particles, hexamethylenediamine and sodium dodecyl benzene sulfonate according to specific parts by mass, and the nano modified particles are a mixture of KH-550 modified nano SiO2 and KH-570 modified nano Al2O3. The phase change performance of the prepared energy storage material adapts to multiple scenes, and the energy storage material is excellent in heat conduction and mechanical performance, good in leakage prevention and cycling stability and capable of being widely applied to the field of phase change energy storage.

The present invention relates to a composition comprising a hydroxy acrylic resin and a two-component coating composition comprising the composition, wherein the hydroxy acrylic resin is formed by solution polymerization of a monomer mixture, wherein the monomer mixture comprises, relative to the total weight of the monomer mixture, a) 1-10% by weight of a multifunctional melamine-formaldehyde acrylic resin; b) 10-45% by weight of a hydroxy C1-C20 alkyl (meth)acrylate; and c) 45-80% by weight of other ethylenically unsaturated monomers other than a) and b); wherein the composition has a solids content of at least 75% by weight, based on the weight of the hydroxy acrylic resin. Furthermore, the present invention relates to a two-component coating composition comprising the above-mentioned composition comprising a hydroxy acrylic resin and a polyisocyanate crosslinker.

According to a first aspect, the invention relates to a process for the production, preferably continuous, of calcium sulfate alpha hemihydrate, the process comprising: - the preparation of an aqueous gypsum suspension comprising gypsum in particulate form, water and at least one superplasticizing polymer selected from phosphate polyethers, sulfonated melamine formaldehyde (SMF) and sodium poly(styrene sulfonate); - the calcination of the aqueous gypsum suspension at a suitable temperature and pressure to obtain a suspension of calcium sulfate alpha hemihydrate; - optionally, the filtration of the calcium sulfate alpha hemihydrate suspension to separately obtain a concentrated alpha hemihydrate suspension and an aqueous filtrate.The invention also relates, according to a second aspect, to a process for preparing a gypsum-based product comprising the preparation of a plaster suspension comprising calcium sulfate alpha hemihydrate obtained by the process according to the invention. Furthermore, the invention relates to a plaster-based product obtained using a process according to the invention. The invention also relates to a gypsum-based product obtained using a process according to the invention, such as a plasterboard. Figure 2.

The invention relates to the technical field of modified melamine resin, and discloses a modified melamine resin preparation method, which comprises: mixing melamine, a formaldehyde solution, deionized water and a toughening monomer, adjusting the pH value, carrying out a stirring reaction, and after the system becomes clarified, obtaining a mixture; and adding zinc oxide whiskers loaded with the composite porous microspheres into the mixture, stirring and mixing, and cooling to room temperature to obtain the modified melamine resin. The zinc oxide whiskers loaded with the composite porous microspheres and the melamine resin form mechanical interlocking, external stress can be absorbed, then the mechanical strength of the melamine resin is improved, and release of free formaldehyde in the melamine resin is effectively reduced through the dual effects of physical adsorption and chemical fixation; the toughening monomer enlarges the spacing of rigid triazine rings in the melamine resin, and improves the toughness of the melamine resin.

The invention discloses an aqueous zinc ion battery negative electrode, a preparation method thereof and an aqueous zinc ion battery, and belongs to the technical field of energy storage materials. According to the invention, the aqueous zinc ion battery negative electrode material is prepared by coating the surface of a zinc foil with a porous N-Ti3C2Tx nano material; the preparation method of the porous N-Ti3C2Tx nano material comprises the following steps: uniformly mixing a Ti3C2Tx suspension and a melamino-formaldehyde ball dispersion liquid, and carrying out electrostatic adsorption reaction to obtain a mixture; and under the inert gas atmosphere, the mixture is subjected to annealing treatment at the temperature of 500-550 DEG C, and the porous N-Ti3C2Tx nano material is obtained. The porous N-Ti3C2Tx nano material is utilized to effectively improve the problems of uncontrollable growth of zinc dendrites, volume expansion and structure pulverization, hydrogen evolution and corrosion side reaction, slow interface dynamics and poor compatibility of the material and electrolyte in the zinc battery.

The invention provides a preparation method and application of a melamine film, and belongs to the technical field of film materials. The preparation method comprises the following steps: 1) adding an alkaline reagent into an ionic liquid aqueous solution to adjust the pH value, and then sequentially adding paraformaldehyde and melamine for reaction to obtain a melamine formaldehyde prepolymer solution; 2) dissolving cellulose in an ionic liquid, adding the melamine formaldehyde prepolymer solution, and mixing to obtain a membrane preparation solution; 3) carrying out vacuum defoaming and die head extrusion on the membrane preparation solution, immersing the membrane preparation solution in a coagulating bath, and preparing a melamine gel membrane by adopting a phase inversion method; and 4) plasticizing and drying the melamine gel film to obtain the melamine film. The melamine film prepared by blending the melamine formaldehyde prepolymer and the cellulose has the tensile strength of more than 50MPa and the limit oxygen index of more than 28%, has the characteristics of greenness and flame retardance, and has the advantages of no toxic smog and no molten drop in the combustion process.

This invention discloses a water-soluble anti-collapse agent, its preparation method, and a water-based slurry. The raw materials for the water-soluble anti-collapse agent include melamine, formaldehyde aqueous solution, polyol, epichlorohydrin, water, initiator, organophosphonate, and comonomer. The preparation method includes the following steps: mixing melamine and formaldehyde aqueous solution, adjusting the pH, and then reacting; introducing polyol into the reaction system to continue the reaction; then introducing organophosphonate solution into the reaction system, followed by epichlorohydrin to continue the reaction; finally introducing comonomer and initiator to continue the reaction, and then drying and optionally crushing to obtain the water-soluble anti-collapse agent. A water-based slurry containing the above-mentioned water-soluble anti-collapse agent is also provided. The anti-collapse agent provided by this invention has a filtration loss reduction rate of more than 70% against complex salts and a shale secondary rolling recovery rate of more than 80%. It has good salt resistance, temperature resistance, wall consolidation, and filtration loss reduction performance, and also has the advantages of being environmentally friendly, having low fluorescence, and good water solubility.

A readily findable dental appliance is provided having a shell with a plurality of tooth-receiving cavities shaped to receive and resiliently reposition teeth in a patient's mouth from a first arrangement toward a. second arrangement. At least one thermally-sensitive indicator is incorporated with at least a portion of the shell. The thermally-sensitive indicator includes a first temperature-activated thermochromic pigment, which preferably changes from a. first visible color when below a first temperature to a second substantially clear color when above the first temperature. The pigment preferably includes a leuco dye microencapsulated in a polymer such as melamine formaldehyde polymer. A second temperature-activated, thermochromic pigment may be provided, that changes from a. third substantially clear color when above a second temperature to a fourth visible color when below the second temperature, which is, e.g., approximately beverage-drinking temperature.

The invention relates to a composite nano fireproof material, a fireproof pre-reaction solution and a preparation method and application thereof, and the composite nano fireproof material is prepared from organic nanoparticles and organic / inorganic hybrid nanoparticles; in the organic nanoparticles, a core layer is cross-linked polyacrylamide emulsion particles, a bridging layer is prepared from diisocyanate bridging molecules, a branching layer is linear hydroxyl cellulose, the branching layer is arranged on the outer side of the bridging layer, and the core layer is wrapped with the bridging layer; in the organic / inorganic hybrid nanoparticles, a core layer is a SiO2 emulsion particle containing amino and formaldehyde groups, a transition layer is a copolymer layer which has a cross-linked network structure and contains melamine formaldehyde / phosphorus-containing polymer, and a shell layer is a copolymer layer of which the surface is grafted with linear glycidyl methacrylate. According to the invention, the defect that a fireproof layer material in the prior art cannot meet the ultraviolet test is overcome, and the defects of bubbles, gummosis, blackening, low material hardness, poor low temperature resistance and the like of the fireproof layer are avoided.

The present application relates to the technical field of molding compound preparation, specifically disclosing a melamine-formaldehyde molding compound and a preparation method thereof. A melamine-formaldehyde molding compound comprises the following components in weight percentage: 40-60% modified melamine-formaldehyde resin; 10-20% inorganic fiber; 20-40% filler; and 1-2% curing agent. The modified melamine-formaldehyde resin is prepared by the following method: mixing 4,4-diphenylmethane diisocyanate with aminopolyethylene glycol hydroxy to obtain a mixture A; mixing cellulose with mixture A, allowing the mixture to react at a temperature of 100°C to obtain a mixture B; cooling the mixture, adding the mixture to anhydrous ethanol, and precipitating the mixture to obtain an aminopolyethylene glycol hydroxy-cellulose graft copolymer; adjusting the pH of the formaldehyde to alkaline, adding melamine and the aminopolyethylene glycol hydroxy-cellulose graft copolymer, heating the mixture to react, and vacuum dehydrating the mixture to obtain the modified melamine-formaldehyde resin.

This invention belongs to the field of microencapsulation technology, and specifically relates to a high-lasting fragrance microcapsule and its preparation method. The preparation method of the high-lasting fragrance microcapsule provided by this invention includes the following steps: S101, mixing fragrance with hydrophilic particles and ultrasonically dispersing to obtain an oil phase; S102, mixing styrene-maleic anhydride copolymer, a strong acid-resistant anionic emulsifier, and a nonionic emulsifier, adjusting the pH, and stirring evenly to obtain an aqueous phase; S103, mixing melamine, formaldehyde, water, modifier A, and modifier B, heating and stirring, adjusting the pH, and cooling after the reaction to obtain a modified MF prepolymer; S104, adding the oil phase to the aqueous phase for emulsification to obtain an emulsion; S105, adding the modified MF prepolymer to the emulsion for crosslinking, adjusting the pH for curing, and then adding polyvinyl alcohol polymers and glutaraldehyde for secondary encapsulation to obtain the high-lasting fragrance microcapsule. The fragrance microcapsules prepared by this invention achieve a long-lasting fragrance effect and excellent wash resistance.

The present application relates to the technical field of flame-retardant cable, in particular to a kind of armored flame-retardant power cable, including conductor, modified insulation layer, inner liner and armored layer, the modified insulation layer is wrapped in conductor outside, the inner liner is wrapped in modified insulation layer outside, the armored layer is wrapped in inner liner outside.The present application is modified to polyphosphoric ammonium, melamine formaldehyde prepolymer in steps, solve the problem that traditional flame-retardant additive is poor with polyethylene base material Compatibility, easy to agglomerate, modified polyphosphoric ammonium effectively reduces the van der waals force between flame retardant particles, avoids the local agglomeration phenomenon that traditional polyphosphoric ammonium directly added easily occurs, while modified melamine formaldehyde prepolymer plays steric hindrance effect to polyphosphoric ammonium particles, so that it is mixed and fused in the process of insulation base material, let flame retardant realize global uniform distribution in insulating layer, no dispersion dead angle.

The invention discloses a high-weather-resistance decorative plate and a preparation method thereof, and belongs to the technical field of plates. The high-weather-resistance decorative plate comprises a base plate and melamine impregnated bond paper attached to the surface of the base plate through a hot pressing technology. The melamine-impregnated bond paper is obtained by sequentially impregnating raw paper in urea-formaldehyde resin and antibacterial melamine-formaldehyde resin. The preparation method comprises the following steps: firstly, impregnating the raw paper in the urea-formaldehyde resin and the antibacterial melamine-formaldehyde resin; the antibacterial melamine formaldehyde resin is obtained by carrying out a composite reaction on melamine, formaldehyde, (2S)-2-amino-3-hydroxyglutaric acid and antibacterial polyethylene glycol; the antibacterial polyethylene glycol is obtained through a composite reaction of a composite antibacterial filler, sodium methyl silicate, polyethylene glycol and cysteine; the composite antibacterial filler is prepared by the following steps: firstly, by adopting a method of combining molten urea and thermal polycondensation, taking silver nitrate as a silver source and taking citric acid as a pore-forming agent, preparing silver-loaded graphite phase carbon nitride rich in mesopores in situ, and then reacting the silver-loaded graphite phase carbon nitride with phosphorus oxychloride, pentaerythritol and phosphorus oxychloride in sequence.

The present invention discloses a self-supporting cobalt oxide composite electrode, a preparation method thereof, and an application in seawater electrolysis, belonging to the field of battery technology; using melamine formaldehyde-polyethyleneimine resin as an adhesive, a cobalt-based coordination polymer is combined with activated carbon fiber paper, and a composite electrode is obtained after high-temperature annealing, and the composite electrode is applied to seawater electrolysis. In the composite electrode, a nitrogen-doped carbon layer is formed after high-temperature annealing of the melamine formaldehyde-polyethyleneimine resin, which has good electrical conductivity and certain electrocatalytic performance, effectively solving the problem of low electrical conductivity of seawater itself. At the same time, the carbon layer can also protect the electrocatalytic active components wrapped therein, reduce the corrosion of chloride ions in seawater to the electrode, and slow down the precipitation of calcium and magnesium ions on the electrode surface. Compared with the electrode material prepared by the traditional in situ growth method, the electrode prepared by the present invention has better stability and anti-interference ability and longer service life.

The invention relates to toughened modified melamino-formaldehyde resin and a preparation method thereof, and belongs to the technical field of melamino-formaldehyde resin preparation. The modified lignin, the white carbon black and other substances are added in the modified preparation process of the melamine formaldehyde resin, so that the toughness and wear resistance of the resin can be obviously enhanced.

A metal oxide varistor (MOV) device including a MOV chip, electrically conductive first and second electrodes disposed on opposite sides of the MOV chip, electrically conductive first and second leads connected to the first and second electrodes, respectively, and an arc mitigating, flame retarding coating covering the MOV chip, the first and second electrodes, and portions of the first and second leads, the arc mitigating, flame retarding coating comprising a silicone composition formed of a filler material suspended in a silicone resin, wherein the filler material includes one or more of melamine, guanidine, guanine, hydantoin, allantoin, urea, melamine-formaldehyde, melamine-cyanurate polymer, and boric acid.

The present application provides a highly efficient thermally conductive UV-LED ink and a preparation method thereof, comprising 0.1-7% melamine-formaldehyde-modified MXene, 30-60% binder, 30-50% monomer, 1-10% photoinitiator, and 1-10% additive. The present invention uses melamine-formaldehyde resin to embed the MXene to improve the dispersibility of the MXene and solve the technical problem of poor compatibility between the MXene and the ink matrix. Supplemented with a binder, pigment, and various additives, the UV-LED thermally conductive ink is prepared. This not only effectively prevents the agglomeration of the MXene but also greatly improves the thermal conductivity of the thermally conductive ink. The thermal conductivity of the printed ink film in the planar direction is as high as 1.32 W / m·K.

The present invention discloses a method for detecting urea-formaldehyde resin in melamine-formaldehyde materials, comprising the following steps: washing a sample powder with a hydrochloric acid solution, hydrolyzing the sample at 110°C ± 5°C for 60 min ± 5 min, filtering the sample through a polyethersulfone filter membrane to obtain a test solution; and subjecting the test solution to high-performance liquid chromatography-mass spectrometry. The detection method of the present invention achieves highly specific and sensitive identification of the presence of urea-formaldehyde resin in melamine-formaldehyde materials, providing excellent technical support for quality control and safety monitoring of food contact materials and products, and having significant economic and social benefits.

Melamine-formaldehyde foam with improved weather resistance comprising 0.1 to 8 wt.-% of at least one UV stabilizer, such as benzotriazole derivatives and piperidinol derivatives and further 1 to 3 wt.-% of at least one hydrophobicization agent, such as organo-modified siloxanes and silanes and processes for producing such melamine-formaldehyde foams with improved weather resistance.

The application provides a preparation method and application of melamine-formaldehyde modified Mxene, first, melamine-formaldehyde prepolymer is synthesized, then Mxene is prepared by stripping aluminum carbide through a lithium fluoride acid solution, finally, the melamine-formaldehyde prepolymer and the stripped Mxene are in-situ polymerized to obtain melamine-formaldehyde modified Mxene, the melamine-formaldehyde modified Mxene is compounded with each component of ink, and grinding and filtering are carried out, so that high-efficiency heat-conducting UV-LED ink is obtained, the melamine-formaldehyde resin is used for embedding treatment of Mxene, so that the dispersibility of Mxene is improved, the technical problem of poor compatibility of Mxene and an ink matrix is solved, and then, the connecting material, the pigment and various kinds of additives are supplemented, UV-LED heat-conducting ink is prepared, the agglomeration of Mxene is effectively prevented, and the heat conductivity of the heat-conducting ink is greatly improved, and the heat conductivity coefficient of the ink film after printing is up to 1.32 W / m.K in the plane direction.

A composition for use in the manufacture of an in-mould electronic (IME) component, the composition comprising titanium dioxide particles dispersed in a binder, wherein the binder comprises: a cross-linking agent comprising melamine formaldehyde, a thermoplastic resin comprising a hydroxyl group, and a solvent; and the titanium dioxide particles comprise a titanium dioxide core and an outer shell comprising one or more of alumina, silica and zirconia.