A method for preparing and using electron beam cured colored particles

Abstract

The application discloses a preparation method and application of colored particles based on electron beam curing, and belongs to the technical field of fine chemical industry. Small-molecule dyes are used as cores, and polymers capable of electron beam radiation curing are used as shells to prepare colored particles, and colored paint prepared from the colored particles is used to spray and color a board. The application has the characteristics of fast curing speed and low energy consumption, avoids the key difficulties of heat curing and light curing in the coloring and curing of the board, and solves the problems of cracking of small-molecule dyes and difficulty in curing in the coloring of textiles by electron beam curing. The application can be widely applied to the coloring of boards, the coating of building materials, and the fields of vehicle paint, wood and textiles. Compared with traditional coloring and curing technologies, the application has the characteristics of short time consumption and low energy consumption.

Description

Technical Field

[0001] This invention relates to a method for preparing colored particles based on electron beam curing and its application, belonging to the field of fine chemical technology. Background Technology

[0002] Electron beam curing (EB curing) is a technology that uses a high-energy electron beam to irradiate materials. It features fast curing speed, low energy consumption, no VOC emissions, and is suitable for temperature-sensitive substrates. Currently, electron beam curing colorants typically include resins, curing agents, binders, additives, and colorants such as pigments or small-molecule dyes. Although electron beam curing colorants are widely used in flat panel coating, current colorants are usually in blended form, requiring the addition of large amounts of additives, increasing the risk of formaldehyde release. Pigments or small-molecule dyes usually exist in a dispersed state in the system, making it difficult to ensure uniformity, and small-molecule dyes can migrate and decompose during electron beam curing.

[0003] Polymer-based dyes are created by covalently anchoring small-molecule colorants to polymer chains, protecting them from migration and effectively improving colorfastness in printing. Currently, the most widely used curing methods for polymer-based dyes are photocuring and thermal curing. These methods necessitate the addition of additional additives; for example, thermal curing requires adhesives and curing agents, while photocuring requires initiators. These additives continuously release formaldehyde and VOCs, leading to environmental pollution and posing a threat to human health. With the increasing demands for green and environmentally friendly production, developing a low-energy, fast-acting colorant that integrates fixing and coloring functions has significant application value. Summary of the Invention

[0004] [Technical Issues]

[0005] During electron beam curing, small molecule dyes are prone to degradation, making it difficult to achieve curing and coloring. Traditional curing methods for colorants (thermal curing and photocuring) require the addition of adhesives or initiators, which release formaldehyde and VOC gases, leading to environmental pollution.

[0006] [Technical Solution]

[0007] To address the aforementioned problems, this invention designs and develops a method for preparing and applying electron beam-cured coloring particles. Specifically, this invention relates to coloring particles that can be cured by electron beam, possessing a core-shell structure. The core material is a pigment or dye, and the shell material is a polymer with encapsulation and protection functions that can be cured by electron beam irradiation. Because the small molecule dye is covalently anchored by the polymer, degradation and migration under electron beam irradiation conditions are avoided. Simultaneously, the shell material can be cured by electron beam irradiation without the need for additional adhesives or initiators, significantly reducing the release of formaldehyde and VOCs. This invention can be widely applied to coloring of boards, coating of building materials, and also to automotive paint, wood, textiles, and other fields. Compared to traditional coloring and curing technologies, it features shorter processing time and lower energy consumption.

[0008] To achieve the above objectives, the present invention provides a coloring particle based on electron beam curing; the coloring particle is composed of a core material and a wall material; the core material includes a dye; the wall material includes a polymer that can be electron beam radiation-polymerized and grafted, and the mass of the core material accounts for 0.1-8% of the mass of the wall material.

[0009] In one embodiment of the present invention, the dye includes at least one of the following: anthraquinone-type dyes with alkene double bonds, disperse violet 93, disperse blue 73, disperse blue 60, disperse yellow 64, disperse red 79, carbon black, phthalocyanine pigment, titanium dioxide, and chrome green.

[0010] In one embodiment of the present invention, the electron beam radiation-polymerizable graft polymer includes at least one of acrylonitrile, polyurethane, ethylene-vinyl acetate copolymer (EVA), isobornyl acrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, methacrylic acid, and glycidyl methacrylate.

[0011] This invention also discloses a method for preparing colored particles based on electron beam curing, comprising the following steps:

[0012] 1) Oil phase preparation: Using dye as core material and polymer grafted by electron beam radiation polymerization as wall material, the core material and wall material are added to a beaker, mixed and stirred thoroughly, and then a co-emulsifier and initiator are added to prepare the oil phase;

[0013] 2) Aqueous phase preparation: Add emulsifier and deionized water to a beaker and stir until homogeneous to prepare the aqueous phase;

[0014] 3) Emulsion preparation: The oil phase prepared in step 1) is slowly added to the aqueous phase prepared in step 2), and emulsified using a high-speed emulsifier. The emulsified emulsion is then transferred to a three-necked flask and mechanically stirred to obtain the emulsion.

[0015] 4) Preparation of electron beam cured coloring particles: The emulsion obtained in step 3) is heated, the rotation speed is reduced, and the initiator is slowly added to the emulsion multiple times. After reacting for a period of time, an electron beam cured coloring particle dispersion is obtained. After filtration, centrifugation, washing and drying, electron beam cured coloring particles are obtained.

[0016] In one embodiment of the present invention, the mass of the core material accounts for 0.1-8% of the mass of the wall material.

[0017] In one embodiment of the present invention, the co-emulsifier includes one or more of hexadecane, hexadecyl alcohol, glycerol, and fatty acid sorbitan emulsifiers.

[0018] In one embodiment of the present invention, the initiator includes at least one selected from benzoyl peroxide, azobisisobutyronitrile, azobisisoheptanenitrile, persulfate, and azobisisobutylamidine dihydrochloride.

[0019] In one embodiment of the present invention, the co-emulsifier accounts for 1-5% of the wall material mass.

[0020] In one embodiment of the present invention, the initiator accounts for 0.1-5% of the wall material mass.

[0021] In one embodiment of the present invention, the emulsifier in step (2) includes one or more of DM1501, Span 20, Span 40, Span 60, DNS-86, SR-10, TMN-10, TMN-6, sodium p-styrene sulfonate, and DNS-628.

[0022] In one embodiment of the present invention, the mass ratio of emulsifier to core material in step (2) is 0.5-2:1.

[0023] In one embodiment of the present invention, the mass ratio of the oil phase to the water phase in step (3) is 1:1.2-3.

[0024] In one embodiment of the present invention, the amount of initiator added in step (4) is 0.5-5% of the total mass of the oil phase.

[0025] In one embodiment of the present invention, the reaction temperature in step (4) is 60-80℃, the rotation speed is 500-100rpm, and the reaction time is 5-7h.

[0026] In one embodiment of the present invention, the particle size of the electron beam cured coloring particles is 100-500 nm.

[0027] The present invention also provides an application of the above-mentioned electron beam curing coloring particles in the coloring of sheet materials.

[0028] In one embodiment of the present invention, the application involves coloring a board by spraying a paint containing electron beam-cured coloring particles, and then obtaining a colored board by electron beam curing.

[0029] In one embodiment of the present invention, the spraying method involves preparing the above-mentioned paint containing electron beam curable coloring particles into a paint material, uniformly coating it onto the board by spraying, and obtaining a colored board material after electron beam curing.

[0030] In one embodiment of the present invention, the paint containing electron beam cured coloring particles comprises, by mass percentage, 5-20% electron beam cured coloring particles, 1%-10% dispersant, 1%-10% crosslinking agent, 0.5-10% thickener, and the balance being deionized water, and the viscosity of the paint is 100-2000 cps.

[0031] In one embodiment of the present invention, the spraying method is to use a spray gun to spray on a room-temperature dry board at intervals of 20-30cm, at a spraying speed of 30-60cm / s, spraying in small amounts multiple times, and controlling the spraying thickness to be 0.5-3mm.

[0032] In one embodiment of the present invention, the dispersant includes one or more of sodium lignosulfonate, sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, styrene-maleic anhydride copolymer, AX-20, and NNO.

[0033] In one embodiment of the present invention, the crosslinking agent includes one or more of hydroxyethyl acrylate, trimethylolpropane triacrylate, hydroxyethyl methacrylate, N-hydroxymethylacrylamide, N,N-dimethylacrylamide, acrylic acid, and dodecyl methacrylate.

[0034] In one embodiment of the present invention, the thickener includes one or more of sodium alginate, xanthan gum, starch derivatives, carboxymethyl cellulose (CMC), methyl cellulose, and polyacrylic acid polymers.

[0035] In one embodiment of the present invention, the radiation dose of the electron beam curing is 10kGy-100kGy, and the curing time is 0.1-3s.

[0036] The beneficial effects of this invention are as follows:

[0037] (1) This invention provides a method for preparing and applying electron beam-cured coloring particles. The method uses small molecule dyes as the core and a polymer that can be cured by electron beam radiation as the shell to form coloring particles, which are then used to prepare colorant paints for spraying coloring boards. Compared with paints prepared by conventional methods, this invention formulates coloring particles with a core-shell structure by combining dyes and polymerizable monomers, and then disperses the coloring particles with crosslinking agents and dispersants to prepare the paint. The paint prepared by this invention, after coloring the boards, exhibits good color fastness and minimal color difference. Most importantly, this method helps reduce the release of formaldehyde from the boards.

[0038] (2) The method of the present invention has the characteristics of fast curing speed and low energy consumption, avoids the key problems of thermal curing and light curing in the coloring and curing of boards, and solves the problem of the cracking of small molecule dyes during electron beam curing and the difficulty in curing when coloring boards.

[0039] (3) The coloring particles of the present invention can be widely used in the coloring of boards, building material coatings, and also in the fields of automotive paint, wood, and textiles. Compared with traditional coloring and curing technologies, they have the advantages of short time consumption and low energy consumption. Detailed Implementation

[0040] The present invention will be further described below through specific embodiments, but the implementation of the present invention is not limited thereto.

[0041] Example 1:

[0042] (1) A method for preparing colored particles based on electron beam curing

[0043] Weigh out a mixed solution of 18g acrylonitrile and 2g hydroxyethyl acrylate, and weigh out 0.86g Disperse Yellow 64. Slowly add these to the system and stir until homogeneous to obtain the oil phase. Then add 0.2g hexadecane and 0.6g azobisisobutyronitrile. Mix 1.34g emulsifier SR-10 and 30g water until homogeneous to obtain the aqueous phase.

[0044] Emulsification was performed using a high-speed emulsifier. During the emulsification process, the oil phase was slowly added to the aqueous phase. The emulsifier speed was set to 4000 r / min, and the high-speed emulsification time was 20 min. The emulsified emulsion was then transferred to a three-necked flask, and the oil bath temperature was set to 50℃. The speed was set to 1000 r / min, and the mixture was mechanically stirred for 30 min to obtain a pre-emulsion.

[0045] The system was heated to 70°C, the rotation speed was reduced to 700 r / min, and prepolymerized for 2 h; then the temperature was raised to 80°C, the rotation speed was reduced to 300 r / min, and 5 mL of 3% ammonium persulfate aqueous solution was added dropwise. The reaction was carried out for 3 h, and 5 mL of 3% ammonium persulfate aqueous solution was added dropwise. The mixture was filtered, centrifuged and washed to obtain electron beam-cured colored particles.

[0046] (2) Application of electron beam cured coloring particles in sheet coloring

[0047] Weigh 10g of the electron beam cured coloring particles prepared in step (1) of Example 1, add 5g of SR-10, 1g of trimethylolpropane triacrylate, and 30g of water to obtain a spraying slurry. Apply the slurry to the surface of the substrate using a spraying method, with a 30cm interval, a spraying speed of 10cm / s, and multiple small applications to achieve a coating thickness of 1mm. After uniform spraying, perform electron beam curing at an energy of 50kGy for 1s to obtain an electron beam cured coloring substrate.

[0048] The formaldehyde emission, lightfastness, and energy consumption of the colored boards prepared by the above method were evaluated. Formaldehyde emission was measured using the climate chamber method in GB18580-2001. Lightfastness was determined using the method in GB / T 17657-2013, where the color-fixed board was irradiated with ultraviolet light for 300 hours, and the color difference was obtained by comparing the sample with an unirradiated sample. The ΔE value was tested by taking different points on the same colored board and calculating the color difference.

[0049] Example 2

[0050] The acrylonitrile in step (1) of Example 1 was adjusted to be an ethylene-vinyl acetate copolymer.

[0051] Example 3

[0052] The trimethylolpropane triacrylate in step (2) of Example 1 was changed to dodecyl methacrylate.

[0053] Example 4

[0054] The electron beam curing energy of Example 1 was adjusted to 70 kGy, while other conditions remained unchanged.

[0055] Comparative Example 1

[0056] The electron beam curing energy in Example 1 was adjusted to 5 kGy, while other conditions remained unchanged.

[0057] Comparative Example 2

[0058] The electron beam curing energy in Example 1 was adjusted to 200 kGy, while other conditions remained unchanged.

[0059] Comparative Example 3

[0060] The application in step (2) of Example 1 is adjusted as follows: weigh the electron beam curing coloring particles prepared in Example 1, the amount is 10%, add 10% trimethylolpropane triacrylate and 5% adhesive DM5128, add 5% SR-10 and the balance deionized water, adjust the electron beam curing method to thermosetting method, and perform hot pressing after spraying. The hot pressing temperature is 120℃ and the pressure is 8Mpa.

[0061] Comparative Example 4

[0062] The application in step (2) of Example 1 was adjusted to weigh 10% of the electron beam-cured colored particles prepared in Example 1, add 10% trimethylolpropane triacrylate and 3% photoinitiator 1173, add 5% SR-10 and the remainder deionized water. The electron beam curing method was adjusted to photocuring, using ultraviolet light in the 465nm band at a distance of 15cm and a curing time of 5min.

[0063] Comparative Example 5

[0064] The spraying slurry in step (2) of Example 1 was changed to commercially available board paint. The curing method was changed to heat curing. After spraying, hot pressing was performed. The hot pressing temperature was 120℃ and the pressure was 8Mpa.

[0065] Comparative Example 6

[0066] The spraying slurry in step (2) of Example 1 was adjusted to a commercially available board paint. The curing method was electron beam curing.

[0067] Comparative Example 7

[0068] The spray slurry composition in step (2) of Example 1 is adjusted to be: 10g epoxy acrylate, 5g amino acrylate, 5g glycidyl methacrylate, 0.6g dispersant SR-10, 5g chrome green, 3g talc (3000 mesh), 2g wetting agent X-405, and 3g leveling agent BYK316. The slurry is a mixture of these substances.

[0069] Comparative Example 8

[0070] The spraying slurry in step (2) of Example 1 was adjusted to be a mixture of 10g epoxy acrylate, 5g amino acrylate, 5g glycidyl methacrylate, 0.6g dispersant SR-10, 3g dispersant yellow 64, 3g talc powder (3000 mesh), 2g wetting agent X-405, and 3g leveling agent BYK316.

[0071] Table 1 Performance of Electron Beam Cured Colored Sheets

[0072]

[0073] As shown in Examples 1 and 4 and Comparative Examples 1 and 2, the formaldehyde release during electron beam curing originates from the formaldehyde released by the board itself. When the electron beam radiation intensity is too low, the curing effect cannot be achieved, resulting in incomplete cross-linking of the cross-linking agent and coloring particles. When the electron beam energy is high, it can lead to over-cross-linking, reducing the mechanical properties of the board, and can also cause polymer decomposition, resulting in a decrease in mechanical properties and consequently a decrease in the lightfastness of the board.

[0074] As can be seen from Example 1 and Comparative Example 3, electron beam radiation curing has a coloring effect that is almost the same as that of thermal curing, but the energy consumption is significantly reduced, and the use of adhesives is avoided, which greatly reduces the formaldehyde release.

[0075] As can be seen from Example 1 and Comparative Example 4, electron beam curing can solve the problem of difficult curing of colored systems in UV curing systems. It is superior to UV curing in all aspects, and can avoid the use of initiators, thus reducing formaldehyde release.

[0076] As demonstrated in Example 1 and Comparative Examples 5 and 6, commercially available panel paints are not suitable for electron beam curing. Furthermore, the formaldehyde release from the electron beam-cured coloring particles is significantly lower than that of commercially available panel paints.

[0077] As can be seen from Example 1 and Comparative Examples 7 and 8, compared with traditional electron beam cured coatings, the electron beam cured coloring particles have extremely small color difference and can be applied to small molecule dyes. This indicates that there are no migration or dye molecule decomposition problems during the electron beam curing process, thus broadening the application range of electron beam curing.

[0078] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. The application of electron beam-cured coloring particles in the coloring of sheet metal, characterized in that, The application involves spraying a slurry containing electron beam-curable coloring particles onto a substrate, followed by electron beam curing to obtain the colored substrate. The radiation dose during electron beam curing is 10 kGy-100 kGy, and the curing time is 0.1-3 seconds. The slurry, by mass percentage, comprises 5-20% electron beam-curable coloring particles, 1%-10% dispersant, 1%-10% crosslinking agent, 0.5-10% thickener, and the balance being deionized water. The viscosity of the slurry is 100-2000 ppm. cps; wherein the electron beam cured coloring particles are composed of a core material and a wall material; the core material includes a dye; the wall material includes a polymer that can be electron beam radiation polymerized and grafted, and the mass of the core material accounts for 0.1-8% of the mass of the wall material; the crosslinking agent includes one or more of hydroxyethyl acrylate, trimethylolpropane triacrylate, hydroxyethyl methacrylate, N-hydroxymethylacrylamide, N,N-dimethylacrylamide, acrylic acid, and dodecyl methacrylate; the polymer that can be electron beam radiation polymerized and grafted includes at least two of acrylonitrile, ethylene-vinyl acetate copolymer, isobornyl acrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, methacrylic acid, and glycidyl methacrylate obtained by free radical polymerization.

2. The application according to claim 1, characterized in that, The dyes include at least one of the following: anthraquinone-type dyes with alkene double bonds, disperse violet 93, disperse blue 73, disperse blue 60, disperse yellow 64, disperse red 79, carbon black, phthalocyanine pigments, titanium dioxide, and chrome green.

3. The application according to claim 1 or 2, characterized in that, The method for preparing the colored particles includes the following steps: 1) Preparation of oil phase: Using dye as core material and polymer grafted by electron beam radiation polymerization as wall material, the core material and wall material are added to a beaker, mixed and stirred thoroughly, and then a co-emulsifier and initiator are added to prepare the oil phase; 2) Aqueous phase preparation: Add emulsifier and deionized water to a beaker and stir until homogeneous to prepare the aqueous phase; 3) Emulsion preparation: The oil phase prepared in step 1) is slowly added to the aqueous phase prepared in step 2), the mass ratio of the oil phase to the aqueous phase is 1:1.2-3, and emulsification is performed using a high-speed emulsifier. The emulsified emulsion is then transferred to a three-necked flask and mechanically stirred to obtain the emulsion. 4) Preparation of electron beam cured coloring particles: The emulsion obtained in step 3) is heated, the rotation speed is reduced, and the initiator is slowly added to the emulsion multiple times. After reacting for a period of time, an electron beam cured coloring particle dispersion is obtained. After filtration, centrifugation, washing and drying, electron beam cured coloring particles are obtained. The particle size of the coloring particles is 100-500 nm.

4. The application according to claim 3, characterized in that, The co-emulsifier includes one or more of hexadecane, hexadecyl alcohol, glycerol, and fatty acid sorbitan emulsifiers, and the mass of the co-emulsifier accounts for 1-5% of the wall material mass.

5. The application according to claim 3, characterized in that, The initiator includes at least one of benzoyl peroxide, azobisisobutyronitrile, azobisisoheptanenitrile, persulfate, and azobisisobutylamidine dihydrochloride, and the initiator accounts for 0.1-5% of the wall material mass.

6. The application according to claim 3, characterized in that, The emulsifier mentioned in step (2) includes one or more of DM1501, Span 20, Span 40, Span 60, DNS-86, SR-10, TMN-10, TMN-6, sodium p-styrene sulfonate, and DNS-628, and the mass ratio of the emulsifier to the core material is 0.5-2:

1.

7. The application according to claim 3, characterized in that, The amount of initiator added in step (4) is 0.5-5% of the total mass of the oil phase, the reaction temperature is 60-80℃, the rotation speed is 500-100rpm, and the reaction time is 5-7h.

8. The application according to claim 1, characterized in that, The dispersant includes one or more of sodium lignosulfonate, sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, styrene-maleic anhydride copolymer, AX-20, and NNO, and the thickener includes one or more of sodium alginate, xanthan gum, starch derivatives, carboxymethyl cellulose, methyl cellulose, and polyacrylic acid polymers.

9. A method for preparing a colored sheet, characterized in that, The method involves spraying the slurry containing electron beam-curable coloring particles as described in claim 1 onto a substrate, followed by electron beam curing to obtain the colored substrate. The radiation dose during electron beam curing is 10 kGy-100 kGy, and the curing time is 0.1-3 s. The slurry, by mass percentage, comprises 5-20% electron beam-curable coloring particles, 1%-10% dispersant, 1%-10% crosslinking agent, 0.5-10% thickener, and the balance being deionized water. The viscosity of the slurry is 100-2000 cps. The electron beam-curable coloring particles consist of a core material and a wall material. The core material includes a dye, and the wall material includes a polymer that can be grafted and polymerized by electron beam radiation. The mass of the core material accounts for 0.1-8% of the wall material mass.

10. A paste for coloring boards, characterized in that, The slurry for the colored board, by weight percentage, comprises 5-20% electron beam cured coloring particles as described in claim 1, 1%-10% dispersant, 1%-10% crosslinking agent, 0.5-10% thickener, and the balance being deionized water; the viscosity of the slurry is 100-2000 cps; the electron beam cured coloring particles consist of a core material and a wall material; the core material comprises a dye; the wall material comprises a polymer that can be grafted by electron beam radiation polymerization, and the mass of the core material accounts for 0.1-8% of the mass of the wall material.

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