Modified epoxy emulsion, preparation method thereof and application of modified epoxy emulsion in three-dimensional anti-counterfeiting temperature-variable ink

Abstract

The invention belongs to the technical field of high polymer materials, and relates to a modified epoxy emulsion which comprises 70-80 parts of epoxy resin, 5-7 parts of an emulsifier, 0.4-0.8 part of an initiator, 60-80 parts of a mixed monomer and 180-220 parts of water. The mixed monomer is prepared from a soft and hard acrylic monomer, acrylic acid, glycidyl methacrylate, alkenyl silane modified nano silicon dioxide and caprolactone acrylate according to a specific proportion. The invention also discloses a preparation method of the modified epoxy emulsion, and in-situ grafting of nano silicon dioxide is realized by adopting a pre-emulsion step-by-step dropwise adding process. When the emulsion is applied to the three-dimensional anti-counterfeiting temperature-sensitive ink, the emulsion has a synergistic effect with expanded microspheres grafted with amino-containing benzene rings on the surfaces: epoxy groups of glycidyl methacrylate and amino groups on the surfaces of the expanded microspheres are crosslinked to form an interpenetrating network, nano silicon dioxide is dispersed in the interpenetrating network as a rigid node, and caprolactone chain segments provide network elasticity, so that the three-dimensional anti-counterfeiting temperature-sensitive ink is prepared. Therefore, the ink has high adhesive force, excellent wear resistance and weather resistance, and is particularly suitable for printing temperature change-three-dimensional double anti-counterfeiting marks.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of high polymer materials, and relates to an epoxy emulsion, in particular to a modified epoxy emulsion, a preparation method thereof and application of the modified epoxy emulsion to a three-dimensional anti-fake temperature-variable ink. BACKGROUND

[0002] Water-based resin is the inevitable development direction of low carbon, environmental protection and sustainable development. The epoxy resin emulsion can have excellent adhesion on various substrates due to the presence of hydroxyl groups and epoxy groups, and is widely used in coatings and inks. However, the traditional epoxy resin emulsion has two major defects: one is poor resistance to friction, which leads to easy wear after film formation; and the other is insufficient toughness, which leads to easy brittle fracture after film formation, thereby limiting its application as an environmentally friendly film-forming component in fields with high durability requirements (for example, anti-fake).

[0003] The three-dimensional anti-fake temperature-variable ink is an important application of ink in the field of anti-fake, which can strengthen the anti-fake function through the temperature-induced color change and heating expansion of the anti-fake mark, realize double anti-fake, and increase the interestingness of the product. The epoxy emulsion can endow the temperature-variable ink with excellent adhesion, thereby maintaining the adhesion of the anti-fake mark pattern for a long time. However, in the actual application environment, the poor resistance to friction will lead to the inability to identify the anti-fake mark pattern for a long time, and due to the irreversibility of the three-dimensional effect of the pattern, the poor wear resistance, low blister wall strength and poor supportability will also weaken the three-dimensional effect, and even cause the pattern to collapse. In addition, the poor flexibility of the epoxy emulsion will also easily lead to poor stability of the three-dimensional pattern after expansion, poor water resistance and poor weather resistance, thereby leading to poor anti-fake identification effect. The existing expansion microspheres have poor dispersion stability in the ink, and after high-temperature expansion, the interface bonding force is weak and the microspheres are easy to collapse. In addition, the epoxy / acrylic copolymer emulsion is prone to phase separation, which leads to a decrease in water resistance.

[0004] The existing conventional acrylic-modified epoxy emulsion cannot simultaneously solve the problems of resistance to friction, flexibility and interface bonding force. Therefore, it is necessary to seek an epoxy emulsion with high resistance to friction, strong adhesion and good three-dimensional effect for use in a three-dimensional anti-fake temperature-variable ink. SUMMARY

[0005] In view of the problems of the resistance to friction and flexibility of the existing epoxy emulsion, the first object of the present application is to disclose a modified epoxy emulsion.

[0006] TECHNICAL SCHEME

[0007] The modified epoxy emulsion comprises, by mass fraction, 70-80 parts of epoxy resin, 5-7 parts of emulsifier, 0-0.8 parts of initiator, 60-80 parts of mixed monomers, and 180-220 parts of water; wherein the mixed monomers comprise soft and hard acrylic monomers, acrylic acid, glycidyl methacrylate, alkenyl silane modified nano-silica, and caprolactone acrylate; further, the soft and hard acrylic monomers comprise butyl acrylate and methyl methacrylate.

[0008] In the preferable disclosure of the present application, the epoxy resin is bisphenol A type, the emulsifier is a mixture of nonylphenol polyoxyethylene ether (OP-10) and sodium dodecyl benzene sulfonate (SDBS) in a mass ratio of 1:1, and the initiator is sodium persulfate.

[0009] In the preferable disclosure of the present application, the mass ratio of the soft and hard acrylic monomers, the acrylic acid, the glycidyl methacrylate, the alkenyl silane modified nano-silica, and the caprolactone acrylate in the mixed monomers is 10:8:2-4:4-6:3, and preferably, the mass ratio of the glycidyl methacrylate and the alkenyl silane modified nano-silica is 3:5.

[0010] In the preferable disclosure of the present application, the alkenyl silane modified nano-silica is obtained by dehydration of silanol and surface hydroxyl of nano-silica after hydrolysis of alkenyl silane coupling agent, and the modified nano-silica has unsaturated double bonds grafted on the surface.

[0011] It can be understood that any method for grafting nano-silica with polymerized monomers can be used in the preparation of the present application, and the present application uses a conventional silane treatment process.

[0012] The acrylic resin has excellent weather resistance and acid and alkali resistance, and the combination of the two resins can improve the weather resistance of the prepared film-forming emulsion, and the modified resin can improve the adhesion of the emulsion on different substrates. In order to further improve the wear resistance and flexibility of the epoxy emulsion, the alkenyl silane modified nano-silica and caprolactone acrylate are used as functional monomers to participate in the modification and polymerization to obtain the acrylic resin modified epoxy polymer emulsion. The nano-silica grafted on the side of the acrylic acid segment in the polymer can improve the friction resistance of the emulsion, and can improve the strength of the ink. The nano-silica grafted on the side does not easily agglomerate, and can stably exist in the ink, which is more conducive to improving the wear resistance, weather resistance, ink strength and scratch resistance. Meanwhile, the caprolactone acrylate grafted on the side provides a flexible segment, reduces the interface stress concentration, improves the impact resistance, improves the processing flowability of the emulsion, and improves the water resistance of the emulsion. The flexible caprolactone segment in the crosslinked network after curing reduces the possibility of cracking after the expansion of the three-dimensional ink.

[0013] The application utilizes a conventional preparation method of acrylic modified epoxy emulsion, and realizes the performance improvement of the epoxy emulsion in terms of friction resistance and flexibility based on a simple process through the participation of specific functional monomers in polymerization.

[0014] The second object of the application is to disclose the preparation method of the modified epoxy emulsion.

[0015] The preparation method of the modified epoxy emulsion comprises the following steps: dissolving 1 / 2 mass of emulsifier in 1 / 2 mass of water to prepare an emulsifier solution, mixing and dispersing the epoxy resin and the mixed monomers, and then slowly adding the emulsifier solution to form a pre-emulsion; preparing an initiator solution by mixing and dispersing 1 / 6 mass of emulsifier, an initiator, and 1 / 6 mass of water; mixing and dispersing 1 / 3 mass of emulsifier and 1 / 3 mass of water, heating to 80-85 DEG C under a nitrogen atmosphere, and slowly adding the pre-emulsion and the initiator solution at the same time, respectively, for 4-6 h, and continuing to keep warm for 1-2 h; cooling to 30-40 DEG C, adjusting the pH to 7 with ammonia water, and obtaining the product.

[0016] It can be understood that the preparation method selects the above-mentioned emulsifier, initiator, epoxy resin and mixed monomers, and the prepared modified epoxy emulsion has the performance of the modified epoxy emulsion described in the first object.

[0017] The third object of the application is to disclose a three-dimensional anti-fake temperature change ink product, which comprises the following raw materials in parts by mass: 70-90 parts of modified epoxy emulsion; 15-25 parts of temperature-sensitive color powder; 18-26 parts of expanded microspheres; 0.8-2 parts of dispersing agent; 0.5-1 part of defoaming agent; 0.5-1 part of leveling agent; and 5-15 parts of water.

[0018] In the preferred disclosure of the application, the expanded microspheres are obtained by a suspension polymerization method using a polymerization monomer and isobutane.

[0019] In the preferred disclosure of the application, the polymerization monomer comprises methyl methacrylate, acrylonitrile and 3-butene-1-amine; the preparation of the expanded microspheres is carried out by a conventional suspension polymerization, that is, a microsphere structure with isobutane as the core and an acrylic resin as the shell is formed; the methyl methacrylate and the acrylonitrile are the main wall material polymerization monomers, and the content of the 3-butene-1-amine is less than 15% of the total amount of the polymerization monomers, and more preferably less than or equal to 10%, so as to be able to graft the corresponding benzene ring structure.

[0020] Further, the expanded microspheres are modified into modified expanded microspheres through surface modification by amino benzaldehyde.

[0021] Preferably, the amino benzaldehyde is 2,4-diamino benzaldehyde.

[0022] The method for modifying the surface of the expanded microspheres comprises: reacting aminobenzaldehyde and hydroxylamine to generate an aldoxime containing a phenyl group, and grafting the benzene ring containing an amine group on the surface of the expanded microspheres by reacting the aldoxime with the amino group on the surface of the expanded microspheres, i.e., p-aminobenzaldehyde + NH2OH·HCl -> Ph-CH=N-OH (aldoxime), and condensing the aldoxime with the -NH2 on the surface of the microspheres to generate Ph-CH=N-microsphere.

[0023] Specifically, the preparation process of the modified expanded microspheres comprises:

[0024] S1. Preparation of an oil phase: mix the monomers, add an initiator, isobutane and dimethyl 1,4-butanediol acrylate, stir and disperse for 30 min, remove oxygen by nitrogen blowing to obtain an oil phase;

[0025] S2. Preparation of an aqueous phase: uniformly mix sodium chloride, sodium dodecyl sulfate, polyvinylpyrrolidone, a 50% mass concentration silica aqueous solution and sodium nitrite in water to obtain an aqueous phase;

[0026] S3. Mixing: mix the oil phase and the aqueous phase, heat and react to obtain expanded microspheres;

[0027] S4. Modification: add aminobenzaldehyde into ethanol, then add hydroxylamine hydrochloride and triethylamine, and react to obtain an aldoxime containing a phenyl group; take the expanded microspheres, add the aldoxime containing a phenyl group into ethanol, stir, heat and react to obtain modified expanded microspheres.

[0028] The three-dimensional anti-fake temperature-variable ink product uses an epoxy emulsion as a film-forming material to improve the adhesion of the ink, and the common addition of the temperature-sensitive color powder and the expanded microspheres can make the anti-fake ink based on the three-dimensional expansion at a higher temperature on the basis of the conventional heating temperature-variable color anti-fake, and further strengthen the anti-fake effect.

[0029] It can be understood that the epoxy emulsion of the present application is particularly suitable for the three-dimensional anti-fake temperature-variable ink product due to its excellent adhesion, rubbing resistance and flexibility. The modified epoxy emulsion is the main film-forming emulsion, the temperature-sensitive color powder exhibits the color change function by heating and can be used for the printing of anti-fake marks, and the further expansion of the expanded microspheres caused by the increase in temperature gives the anti-fake marks a three-dimensional effect and strengthens the anti-fake effect.

[0030] The expanded microspheres are of a shell-core structure, the low-boiling-point hydrocarbon liquid in the interior is vaporized in the heating process, the shell layer is softened, and the volume of the expanded microspheres is increased under the action of the internal pressure, which gives the ink layer a three-dimensional structure. However, how to achieve a good three-dimensional effect and how to maintain the long-term anti-fake mark property and the maintenance of the three-dimensional structure are problems that need to be considered. The current anti-fake ink will lose the three-dimensional expansion structure due to poor rubbing resistance, and cannot realize the long-term three-dimensional anti-fake effect due to poor strength and toughness of the three-dimensional structure. In the present application, the inventors solve and optimize the above problems by using a specific modified epoxy emulsion and a specific modified expanded microsphere together to prepare the anti-fake ink.

[0031] Specifically, the 3-butene-1-amine is added in the preparation of the wall material acrylic resin of the expanded microsphere, so that the polymer of the wall material contains fatty amine group side chains, the fatty amine has higher activity than the benzene ring amine group, the amine group is the active point, the benzene ring is grafted on the surface of the expanded microsphere, the benzene ring can enhance the surface rigidity of the expanded microsphere on the one hand, improve the abrasion resistance, so that the three-dimensional structure can better maintain the three-dimensional effect when subjected to external force bearing and extrusion, on the other hand, the expanded microsphere is dispersed in the ink, the benzene ring on the surface can also improve the aging resistance of the ink, the benzene ring can also limit the chain segment freedom, improve the cohesion of the ink layer, and further improve the abrasion resistance.

[0032] In the preparation of the modified epoxy emulsion, a mixed monomer is selected, the mixed monomer includes: soft and hard acrylic monomer, acrylic acid, glycidyl methacrylate, alkenyl silane modified nano silicon dioxide, caprolactone acrylate. Experiments show that the modification of the epoxy emulsion by glycidyl methacrylate and alkenyl silane modified nano silicon dioxide as modification monomers can unexpectedly improve the abrasion resistance and three-dimensional structure strength of the above-mentioned three-dimensional anti-fake temperature change ink when applied to the three-dimensional anti-fake temperature change ink. This may be because the copolymerization modified emulsion obtained by the modification of glycidyl methacrylate and alkenyl silane modified nano silicon dioxide makes the acrylic acid chain segment side grafting have epoxy groups and nano silicon dioxide, the epoxy groups can be crosslinked with the amino groups on the benzene ring on the surface of the expanded microsphere during ink curing, it can be understood that the crosslinking may also include a small amount of amine groups in the polymer of the expanded microsphere wall material, forming a high molecular crosslinking network on the surface of the expanded microsphere, and embedding the benzene ring on the surface of the expanded microsphere into the crosslinking network, further improving the abrasion resistance and strength of the expanded microsphere through the crosslinking and the effect of the benzene ring structure, and strengthening the three-dimensional support effect of the microsphere foaming; in addition, the nano silicon dioxide is also grafted in the acrylic acid chain segment, based on the crosslinking effect of the above-mentioned epoxy groups, the nano silicon dioxide is driven to realize reinforcement in the crosslinking network, and the caprolactone segment in the acrylic acid chain segment endows the crosslinking network with good flexibility. Therefore, through the cooperation of the crosslinking network structure with good flexibility and the embedded benzene ring and nano silicon dioxide, the expanded microsphere can maintain a good expansion ratio while the three-dimensional structure formed has excellent abrasion resistance, and the expanded microsphere is not easy to collapse to cause the loss of the anti-fake pattern.

[0033] The experiment determines that the mass ratio of glycidyl methacrylate and alkenyl silane modified nano silicon dioxide is 3:5, which has better abrasion resistance. It can be understood that the above-mentioned range is sufficient for the epoxy groups to realize crosslinking and anchor the benzene ring on the surface of the expanded microsphere, while introducing an appropriate amount of nano silicon dioxide to cooperatively improve the strength and abrasion resistance, and maintain an acceptable high adhesion.

[0034] Meanwhile, when introducing the phenyl group through amino benzaldehyde, it is found that the modification of 2,4-diamino benzaldehyde compared to amino benzaldehyde, the obtained ink has better rubbing resistance and adhesion. The possible reason is that the presence of double amino in the benzene ring is more conducive to the embedding of the benzene ring in the cross-linked network, promoting the cross-linking of the epoxy resin, realizing better reinforcement and support of the nano silicon dioxide in the network structure, optimizing the stereoscopic and rubbing resistance of the ink, and the presence of double amino promotes better cross-linking in the ink, and further improves the adhesion of the ink. It can be understood that the ink of the present application can realize good self-crosslinking based on the carboxyl and epoxy groups of the resin side chain and the diamino group on the surface of the microsphere, without the need to add additional curing agent, and a small amount of epoxy resin curing agent can also be added as a supplement to promote cross-linking based on the curing requirements of the ink.

[0035] Advantages

[0036] The present application modifies the epoxy emulsion by soft and hard acrylic monomers, acrylic acid, glycidyl methacrylate, alkenyl silane modified nano silicon dioxide and caprolactone acrylate in a specific ratio, and the prepared modified epoxy emulsion has excellent adhesion, rubbing resistance and flexibility. In the alkenyl silane modified nano silicon dioxide, the alkenyl double bond participates in copolymerization, and the silicon hydroxyl group enhances the hydrogen bonding with the resin; the ε-caprolactone ring of caprolactone acrylate is opened to form a flexible polyester chain, and the terminal double bond participates in polymerization. The three-dimensional anti-counterfeiting temperature change ink prepared by the specific modified epoxy emulsion and the modified expanded microspheres has unexpectedly outstanding three-dimensional effect, good rubbing resistance and strong adhesion. The present application modifies the epoxy emulsion by glycidyl methacrylate and alkenyl silane modified nano silicon dioxide as modification monomers and limits their ratio, and combines 2,4-diamino benzaldehyde modified expanded microspheres to further optimize the maintenance of the three-dimensional effect of the anti-counterfeiting ink and the rubbing resistance. The amine-containing benzene ring grafted on the surface of the expanded microspheres is cross-linked with the epoxy group of the glycidyl methacrylate to form an interpenetrating network penetrating the microspheres-resin, and the nano silicon dioxide is dispersed therein as a rigid node, and the caprolactone segment provides network elasticity, and the three realize the 'rigid and flexible' structure. The pre-emulsion step-by-step dropping process makes the nano silicon dioxide grafted in situ on the acrylic acid segment, avoiding the agglomeration problem of direct mixing. DETAILED DESCRIPTION

[0037] The present application will be described in detail below with reference to the examples, so that those skilled in the art can better understand the present application, but the present application is not limited to the following examples.

[0038] In the preparation examples, examples and comparative examples, the epoxy resin was purchased from Nantong Xingchen Synthetic Materials, with the trade name Phoenix 0164, bisphenol A type epoxy resin; the caprolactone acrylate was purchased from Jining Fanghe Chemical Co., Ltd., with the trade name CA, viscosity 68-82 cps@25℃; the temperature-sensitive color powder was purchased from Dongguan Mingbo Anti-fake Technology Co., Ltd., with the type TP3265-60; the nano-silica was purchased from Hangzhou Julei Biological Materials, with the type JL-SP50, particle size 50 nm.

[0039] The emulsifier was a mixture of nonylphenol polyoxyethylene ether (OP-10) and sodium dodecyl benzene sulfonate (SDBS) in a mass ratio of 1:1; the dispersing agent was EFKA PX4780; the defoaming agent was TEGO FOAMEX 805; the leveling agent was BYK-381; and the initiator was sodium persulfate.

[0040] The preparation process of the alkenyl silane modified nano-silica was as follows: 3 g of KH570 methacryloyloxypropyl trimethoxysilane was added into 300 mL of an ethanol aqueous solution (ethanol and water in a volume ratio of 3:1) and stirred and dispersed for 12 min at a speed of 600 r / min, 50 g of nano-silica was added and stirred, heated to 70℃ and refluxed for 4 h, centrifuged, washed with water for 3 times, and dried to obtain the alkenyl silane modified nano-silica.

[0041] Other experimental reagents in the examples or comparative examples were commercially available or obtained by conventional preparation process unless otherwise specified.

[0042] Preparation Example 1

[0043] The preparation process of the expanded microspheres was as follows:

[0044] Preparation of the oil phase: 120 g of acrylonitrile and 80 g of methyl methacrylate were mixed, 2 g of initiator BPO was added, 60 g of isobutane, 0.5 g of dimethyl 1,4-butanediol acrylate were stirred and dispersed for 30 min, and nitrogen was introduced to remove oxygen to obtain the oil phase;

[0045] Preparation of the water phase: 300 g of water was added with 2 g of sodium chloride, 0.2 g of sodium dodecyl sulfate, 0.3 g of polyvinylpyrrolidone, 0.3 g of a 50% mass concentration silica aqueous solution, and 0.02 g of sodium nitrite were uniformly mixed as the water phase;

[0046] Mixing: the oil phase and the water phase were mixed under stirring at 1000 r / min for 10 min, nitrogen was introduced, the temperature was raised to 65℃, and the reaction was carried out for 20 h, then the temperature was lowered, the material was discharged, filtered, washed with water, and dried.

[0047] Preparation Example 2

[0048] The preparation process of the modified expanded microspheres was as follows:

[0049] Preparation Example 2 and Preparation Example 1 differ in that 20 g of 3-buten-1-amine is used to replace the methyl methacrylate in the oil phase, and p-aminobenzaldehyde is used for modification:

[0050] Oil phase preparation: 120 g of acrylonitrile, 60 g of methyl methacrylate, and 20 g of 3-buten-1-amine are mixed, 2 g of initiator BPO is added, 60 g of isobutane, and 0.5 g of dimethyl 1,4-butanediol acrylate is stirred and dispersed for 30 min, and nitrogen is used to remove oxygen to obtain an oil phase;

[0051] Water phase preparation: 300 g of water is added with 2 g of sodium chloride, 0.2 g of sodium dodecyl sulfate, 0.3 g of polyvinylpyrrolidone, 0.3 g of a 50% by mass aqueous silica solution, and 0.02 g of sodium nitrite, and the mixture is uniformly mixed as a water phase;

[0052] Mixing: the oil phase and the water phase are mixed under stirring at 1000 r / min for 10 min, nitrogen is passed, the temperature is raised to 65°C, and reaction is performed for 20 h, the temperature is then lowered, the product is discharged, filtered, washed with water, and dried to obtain expanded microspheres.

[0053] Modification: 10 g of p-aminobenzaldehyde is added to 250 mL of ethanol, 1.3 g of hydroxylamine hydrochloride and 0.7 parts of triethylamine are then added, stirring is performed at 30°C for 5 h, by-products are filtered, and the solvent is distilled to obtain an aldoxime containing a phenyl group; 100 g of expanded microspheres and 10 g of the aldoxime containing a phenyl group are added to 350 mL of ethanol, stirring is performed at 1000 r / min, the temperature is raised to 60°C, and reaction is performed for 3 h, the product is then filtered, washed, and dried after cooling to obtain modified expanded microspheres.

[0054] Preparation Example 3

[0055] Preparation process of the modified expanded microspheres:

[0056] Preparation Example 3 and Preparation Example 2 differ in that 2,4-diaminobenzaldehyde is used for modification:

[0057] Oil phase preparation: 120 g of acrylonitrile, 60 g of methyl methacrylate, and 20 g of 3-buten-1-amine are mixed, 2 g of initiator BPO is added, 60 g of isobutane, and 0.5 g of dimethyl 1,4-butanediol acrylate is stirred and dispersed for 30 min, and nitrogen is used to remove oxygen to obtain an oil phase;

[0058] Water phase preparation: 300 g of water is added with 2 g of sodium chloride, 0.2 g of sodium dodecyl sulfate, 0.3 g of polyvinylpyrrolidone, 0.3 g of a 50% by mass aqueous silica solution, and 0.02 g of sodium nitrite, and the mixture is uniformly mixed as a water phase;

[0059] Mixing: the oil phase and the water phase are mixed under stirring at 1000 r / min for 10 min, nitrogen is passed, the temperature is raised to 65°C, and reaction is performed for 20 h, the temperature is then lowered, the product is discharged, filtered, washed with water, and dried to obtain expanded microspheres.

[0060] Modification: 10g 2,4-diaminobenzaldehyde was added into 250mL ethanol, then 1.3g hydroxylamine hydrochloride, 0.7 parts of triethylamine were added, and the reaction was stirred at 30℃ for 5h. The by-product was filtered, and the solvent was distilled to obtain a phenyl-containing aldoxime. 100g of expanded microspheres and 10g of phenyl-containing aldoxime were added into 350mL of ethanol, and the reaction was stirred at 1000r / min and heated to 60℃ for 3h. After cooling, the product was filtered, washed and dried to obtain modified expanded microspheres.

[0061] Example 1

[0062] Preparation of modified epoxy emulsion:

[0063] Raw material dosage: epoxy resin 75g, emulsifier 6g, initiator 0.6g, mixed monomer 70g, water 200g; mixed monomer: butyl acrylate, methyl methacrylate, acrylic acid, glycidyl methacrylate, alkenyl silane modified nano silica, caprolactone acrylate, mixed in a mass ratio of 7:3:8:3:5:3;

[0064] Process: 1 / 2 mass of emulsifier was dissolved in 1 / 2 mass of water, stirred at 500r / min for 5min to prepare an emulsifier solution. The epoxy resin and the mixed monomer were mixed and dispersed, then the emulsifier solution was added, and the stirring was continued at 800r / min for 30min until the addition was completed, forming a pre-emulsion;

[0065] 1 / 6 mass of emulsifier, initiator, and 1 / 6 mass of water were mixed and stirred at 500r / min for 5min to prepare an initiator solution;

[0066] 1 / 3 mass of emulsifier and 1 / 3 mass of water were mixed and added to the reactor, stirred at 500r / min for 5min to disperse, and then nitrogen was introduced to heat to 83℃. At the same time, the pre-emulsion and the initiator solution were added dropwise, and the dropwise addition rate was controlled at 5h. After the addition was completed, the reaction was continued for 1.5h. The temperature was lowered to 35℃, and the pH was adjusted to 7 with ammonia water.

[0067] Example 2

[0068] Preparation of modified epoxy emulsion: The difference between Example 2 and Example 1 is only in the ratio of the mixed monomers, i.e. the mixed monomers: butyl acrylate, methyl methacrylate, acrylic acid, glycidyl methacrylate, alkenyl silane modified nano silica, caprolactone acrylate, mixed in a mass ratio of 7:3:8:1:7:3.

[0069] Example 3

[0070] Preparation of modified epoxy emulsion: the difference between Example 3 and Example 1 is only in the ratio of mixed monomers, i.e. mixed monomers: butyl acrylate, methyl methacrylate, acrylic acid, glycidyl methacrylate, alkenyl silane modified nano silica, caprolactone acrylate are mixed in a mass ratio of 7:3:8:5:3:3.

[0071] Comparative Example 1

[0072] Preparation of modified epoxy emulsion: the difference between Comparative Example 1 and Example 1 is only in the ratio of mixed monomers, i.e. mixed monomers: butyl acrylate, methyl methacrylate, acrylic acid, alkenyl silane modified nano silica, caprolactone acrylate are mixed in a mass ratio of 7:3:8:8:3, i.e. glycidyl methacrylate is not contained in the mixed monomers, and an equal amount of alkenyl silane modified nano silica is used to replace the glycidyl methacrylate.

[0073] Comparative Example 2

[0074] Preparation of modified epoxy emulsion: the difference between Comparative Example 1 and Example 1 is only in the ratio of mixed monomers, i.e. mixed monomers: butyl acrylate, methyl methacrylate, acrylic acid, glycidyl methacrylate, caprolactone acrylate are mixed in a mass ratio of 7:3:8:8:3, i.e. alkenyl silane modified nano silica is not contained in the mixed monomers, and an equal amount of glycidyl methacrylate is used to replace the alkenyl silane modified nano silica.

[0075] Example 4

[0076] Stereoscopic anti-counterfeiting temperature-changing ink:

[0077] 20g temperature-sensitive color powder and 22g expanded microspheres prepared in Preparation Example 1 are added to 80g modified epoxy emulsion of Example 1, and then 1g dispersant, 0.8g defoaming agent, 0.6g leveling agent, and 10g water for adjusting viscosity are added, and the mixture is stirred at 1000r / min for 20min to be uniform, and then ground to below 10μm to obtain the stereoscopic anti-counterfeiting temperature-changing ink.

[0078] Example 5

[0079] Stereoscopic anti-counterfeiting temperature-changing ink:

[0080] 20g temperature-sensitive color powder and 22g expanded microspheres prepared in Preparation Example 2 are added to 80g modified epoxy emulsion of Example 1, and then 1g dispersant, 0.8g defoaming agent, 0.6g leveling agent, and 10g water for adjusting viscosity are added, and the mixture is stirred at 1000r / min for 20min to be uniform, and then ground to below 10μm to obtain the stereoscopic anti-counterfeiting temperature-changing ink.

[0081] Example 6

[0082] Stereoscopic anti-counterfeiting temperature-changing ink:

[0083] Add 20g of temperature-sensitive pigment and 22g of modified expanded microspheres from Preparation Example 3 to 80g of modified epoxy emulsion from Example 1, then add 1g of dispersant, 0.8g of defoamer, 0.6g of leveling agent, and 10g of water to adjust the viscosity. Stir at 1000r / min for 20min to mix evenly, and grind to below 10μm to obtain the final product.

[0084] Example 7

[0085] 3D anti-counterfeiting thermochromic ink:

[0086] Add 20g of temperature-sensitive color powder and 22g of modified expanded microspheres from Preparation Example 3 to 80g of modified epoxy emulsion from Example 2, then add 1g of dispersant, 0.8g of defoamer, 0.6g of leveling agent, and 10g of water to adjust the viscosity. Stir at 1000r / min for 20min to mix evenly, and grind to below 10μm to obtain the final product.

[0087] Example 8

[0088] 3D anti-counterfeiting thermochromic ink:

[0089] Add 20g of temperature-sensitive color powder and 22g of modified expanded microspheres from Preparation Example 3 to 80g of modified epoxy emulsion from Example 3, then add 1g of dispersant, 0.8g of defoamer, 0.6g of leveling agent, and 10g of water to adjust the viscosity. Stir at 1000r / min for 20min to mix evenly, and grind to below 10μm to obtain the final product.

[0090] Comparative Example 3

[0091] 3D anti-counterfeiting thermochromic ink:

[0092] Add 20g of temperature-sensitive pigment and 22g of modified expanded microspheres from Preparation Example 3 to 80g of modified epoxy emulsion from Comparative Example 1, then add 1g of dispersant, 0.8g of defoamer, 0.6g of leveling agent, and 10g of water to adjust the viscosity. Stir at 1000r / min for 20min to mix evenly, and grind to below 10μm to obtain the final product.

[0093] Comparative Example 4

[0094] 3D anti-counterfeiting thermochromic ink:

[0095] Add 20g of temperature-sensitive pigment and 22g of modified expanded microspheres from Preparation Example 3 to 80g of modified epoxy emulsion from Comparative Example 2, then add 1g of dispersant, 0.8g of defoamer, 0.6g of leveling agent, and 10g of water to adjust the viscosity. Stir at 1000r / min for 20min to mix evenly, and grind to below 10μm to obtain the final product.

[0096] Comparative Example 5

[0097] The difference between Comparative Example 5 and Example 6 is only that the modified epoxy emulsion is different, and the nano-silica is not modified by graft polymerization, but is directly added into the modified epoxy emulsion.

[0098] Preparation of the epoxy emulsion of Comparative Example 5:

[0099] Raw material dosage: epoxy resin 75 g, emulsifier 6 g, initiator 0.6 g, mixed monomer 58 g, nano-silica 12 g, water 200 g; the mixed monomer is a mixture of butyl acrylate, methyl methacrylate, acrylic acid, glycidyl methacrylate, and caprolactone acrylate in a mass ratio of 7:3:8:3:3;

[0100] Process: 1 / 2 mass of emulsifier is dissolved in 1 / 2 mass of water, stirred at 500 r / min for 5 min to prepare an emulsifier solution, the epoxy resin and the mixed monomer are mixed and dispersed, then the emulsifier solution is added, and stirring is performed at 800 r / min for 30 min until the addition is completed, to form a pre-emulsion;

[0101] 1 / 6 mass of emulsifier, initiator, and 1 / 6 mass of water are mixed and stirred at 500 r / min for 5 min to prepare an initiator solution;

[0102] 1 / 3 mass of emulsifier and 1 / 3 mass of water are mixed and added to a reactor, stirred at 500 r / min for 5 min to disperse, nitrogen is introduced to heat to 83℃, and the pre-emulsion and the initiator solution are added dropwise at the same time, and the dropwise addition rate is controlled to be completed in 5 h, and the reaction is continued for 1.5 h; the temperature is lowered to 35℃, ammonia is used to adjust the pH to 7; and then 12 g of KH570 modified nano-silica is added, and stirring is performed at 500 r / min for 10 min to obtain a modified epoxy emulsion.

[0103] Example 9

[0104] Ink weather resistance test

[0105] After the ink printed sample of Example 6 is placed in a UV aging box (0.55 W / m 2 , 60℃) for 500 h, the foaming height loss rate is less than 5%, while the loss rate of Comparative Example 3 is more than 30%.

[0106] Ink performance test:

[0107] Performance tests are performed on the security ink of Examples 4-8 and Comparative Examples 3-5:

[0108] Security ink adhesion: the ink of the examples and comparative examples is mixed with the Hensma Aradur 38-1 modified amine water-based curing agent at a mass ratio of 100:7, printed on a PVC film, and cured, and the adhesion is tested according to GB / T13217.7-2009.

[0109] Anti-fake ink rubbing resistance test: the ink of examples and comparative examples and Hengmu Aradur 38-1 modified amine water-based curing agent were mixed at a mass ratio of 100:7, two tests of each example or comparative example were taken, one was printed on white card, after curing, the temperature was continuously raised to 170 DEG C to expand, the temperature was lowered to room temperature, and the stereoscopic anti-fake ink foaming height 1 (foaming height 1 = paper thickness with foaming ink layer - paper thickness without foaming ink layer) was tested by screw micrometer; the other was printed on white card, after curing, the rubbing tester was used to rub 300 times under the standard force of 17.78N, and the foaming was repeated, the foaming height 2 after rubbing was recorded, and the foaming height loss after rubbing (foaming height loss = foaming height 1 - foaming height 2) was calculated.

[0110] The test results are as follows table 1:

[0111] Table 1 Test result list

[0112]

[0113] Note: + a) adhesion according to GB / T 13217.7-2009 test;

[0114] + b) rubbing condition: 17.78N force, 300 cycles.

[0115] The prior art does not disclose that the glycidyl methacrylate / nano-silica compound is used to modify the epoxy emulsion, and is used to solve the problems of wear resistance and anti-collapse of the stereoscopic ink in cooperation with the benzene ring modified expanded microspheres. The epoxy emulsion and the expanded microspheres prepared by the application are used to prepare the stereoscopic anti-fake ink. The foaming height of the foaming ink in Examples 4-8 can reach more than 580 μm, and the stereoscopic effect is good. The adhesion fastness is more than 90%. According to Reference Examples 4-6 and Table 1, the adhesion fastness and the wear resistance of the ink can be greatly improved by the modification of the amino benzaldehyde during the preparation of the expanded microspheres, and the 2,4-diamino benzaldehyde is more preferred, which further optimizes the adhesion fastness and the wear resistance of the ink, and is more conducive to the long-term anti-fake effect of the ink. According to Reference Example 6, Comparative Examples 3-5 and Table 1, the glycidyl methacrylate and the alkenyl silane modified nano-silica polymer monomer are added together during the preparation of the epoxy emulsion, and compared with the addition of one kind of monomer alone, the wear resistance is greatly improved, and the adhesion fastness is maintained. According to Reference Examples 7-8, the ratio of the glycidyl methacrylate and the alkenyl silane modified nano-silica is 3:5, and the optimal wear resistance and the high adhesion fastness can be obtained. According to Reference Example 6 and Comparative Example 5, the wear resistance and the adhesion of the ink are improved by the grafting copolymerization modification of the epoxy emulsion, which may be due to the fact that the epoxy group of the acrylic segment in the epoxy emulsion drives the embedding of the nano-silica in the crosslinked network on the surface of the expanded microspheres, and the wear resistance is improved in cooperation with the surface benzene ring, and the agglomeration and the sedimentation of the nano-silica are reduced. The direct addition of the unmodified nano-silica (Comparative Example 5) leads to a sudden increase of 14 times in the friction loss, which proves that the in-situ grafting is a necessary step.

[0116] The same glass cover plate (2 cm x 2 cm) is placed on the foaming ink layer, and a 100g weight is pressed on the cover plate. After 10h, the ink layer change in the bearing area is observed. Examples 5-8 do not appear to collapse, and Examples 4 and Comparative Examples 3-4 all appear to collapse to different degrees, which indicates that the glycidyl methacrylate and the alkenyl silane modified nano-silica are added during the modification of the epoxy emulsion, and the surface amino benzene ring of the expanded microspheres is modified, so that a flexible network is formed on the surface of the expanded microspheres. The benzene ring and the nano-silica embedded in the flexible network work together to improve the structural hardness of the foaming ink layer and the foaming support effect, which is conducive to maintaining the long-term anti-fake identification.

[0117] The specific embodiments are only an explanation of the technical solutions of the application, and are not a limitation of the application. Those skilled in the art can make modifications to the embodiments without creative contribution after reading the specification, and the application is protected by the patent law as long as it is within the scope of the claims.

Claims

1. A modified epoxy emulsion, characterized in that, By mass parts include: epoxy resin 70-80 parts, emulsifier 5-7 parts, initiator 0.4-0.8 parts, mixed monomer 60-80 parts, water 180-220; wherein, the mixed monomer includes: soft and hard acrylic monomer, acrylic acid, glycidyl methacrylate, alkenyl silane modified nano silicon dioxide, caprolactone acrylate; the soft and hard acrylic monomer includes butyl acrylate, methyl methacrylate.

2. The modified epoxy emulsion of claim 1, wherein: The epoxy resin is bisphenol A type.

3. The modified epoxy emulsion of claim 1, wherein: The emulsifier is a mixture of nonylphenol polyoxyethylene ether OP-10 and sodium dodecylbenzenesulfonate SDBS in a mass ratio of 1:1, and the initiator is sodium persulfate.

4. The modified epoxy emulsion of claim 1, wherein: The mass ratio of the soft and hard acrylic monomer, acrylic acid, glycidyl methacrylate, alkenyl silane modified nano silicon dioxide and caprolactone acrylate in the mixed monomer is 10:8:2-4:4-6:3, and preferably the mass ratio of the glycidyl methacrylate and alkenyl silane modified nano silicon dioxide is 3:

5.

5. A process for the preparation of the modified epoxy emulsion of any one of claims 1 to 4, comprising: 1 / 2 mass of the emulsifier is dissolved in 1 / 2 mass of water to prepare an emulsifier solution, the epoxy resin and the mixed monomer are mixed and dispersed, and then the emulsifier solution is slowly added to form a pre-emulsion; 1 / 6 mass of the emulsifier, the initiator, and 1 / 6 mass of water are prepared to form an initiator solution; 1 / 3 mass of the emulsifier and 1 / 3 mass of water are mixed and dispersed, and the temperature is raised to 80-85°C under a nitrogen atmosphere, while slowly adding the pre-emulsion and the initiator solution, which are completed in 4-6h respectively, and the reaction is continued for 1-2h; the temperature is lowered to 30-40°C, and the pH is adjusted to 7 with ammonia water to obtain the product.

6. A stereoscopic security thermochromic ink article, characterized by, The modified epoxy emulsion of any one of claims 1-4, 15-25 parts of temperature-sensitive color powder, 18-26 parts of expanded microspheres, 0.8-2 parts of dispersing agent, 0.5-1 parts of defoaming agent, 0.5-1 parts of leveling agent, and 5-15 parts of water.

7. The stereoscopic anti-counterfeit temperature-changing ink product according to claim 6, characterized in that: The expanded microspheres are obtained by suspension polymerization of polymeric monomers and isobutane.

8. The stereoscopic anti-counterfeit temperature-changing ink product according to claim 7, characterized in that: The polymeric monomers include methyl methacrylate, acrylonitrile and 3-butene-1-amine.

9. The stereoscopic anti-counterfeit temperature-changing ink product according to claim 6, characterized in that: The expanded microspheres are modified by surface modification with amino benzaldehyde to obtain modified expanded microspheres.

10. The stereoscopic security ink article according to claim 9, wherein: The amino benzaldehyde is 2,4-diamino benzaldehyde.

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