A UV-curable hot stamping adhesive and its preparation and application method

Abstract

The invention discloses a UV-curable hot stamping adhesive, and the raw materials for preparation include, by weight, 20-40 parts of modified acrylate resin, 25-35 parts of reactive diluent, 10-20 parts of functional resin, 5-10 parts of filler, 1-4 parts of initiator, and 0.1-0.3 parts of dispersant. The invention adopts low-viscosity tetrafunctional polyester acrylate and high-viscosity difunctional polyester acrylate to act together with polyurethane acrylate with a functionality of 2-4, which can increase the toughness of the coating and avoid peeling and slag problems during winding or hot stamping. And the polyurethane acrylate with a functionality of 2-4 is introduced to act together with epoxy acrylate with a viscosity of 900-2000cps, which can improve the adhesion between the hot stamping layer and the hot stamping foil substrate.

Description

Technical Field

[0001] The invention relates to an ultraviolet light curing hot stamping adhesive and a preparation and application method thereof, and relates to C09J, and in particular to the field of adhesives. Background Art

[0002] With the development of science and technology, people's environmental awareness is getting higher and higher. Hot stamping is a typical surface decoration method, which makes the metal or paint on the hot stamping film laminated to the surface of the workpiece being processed. However, the volatilization of solvents in the traditional hot stamping process will cause environmental pollution, affect the health of workers, and greatly limit the development of hot stamping technology. With the advancement of science and technology, more and more water-based adhesives have come into people's sight and applied to the field of hot stamping, but the adhesion of water-based adhesives to hot stamping foil is not good, the coating surface formed is not delicate, and the pattern effect is poor. Therefore, it is very important to develop a hot stamping adhesive that has high adhesion to hot stamping foil, delicate hot stamping patterns, and is resistant to high temperature and high humidity environments.

[0003] Chinese invention patent CN201410510275.X discloses an electrochemical aluminum backing adhesive for UV substrate and its preparation method. The viscosity and solid content of the adhesive are adjusted and controlled by a variety of modified acrylates, which improves the composite fastness of the photocurable substrate and the adhesive. However, the introduction of organic solvents is a traditional solvent-based hot stamping technology. The solvent will evaporate during the hot stamping process, which puts great pressure on environmental protection. Chinese invention patent CN201810113286.2 discloses a digital hot stamping foil adhesive layer coating and its preparation method. By introducing coumarone resin, dammar resin improves the high temperature resistance of the adhesive layer coating. It is applied to digital hot stamping technology, so that the digital hot stamping foil has good adhesion with carbon powder or varnish. Under hot stamping methods such as heating or light curing, a large area of ​​solid or fine hollow pattern hot stamping effect can be achieved. However, the butanone and butyl acetate used will evaporate during the processing, aggravating environmental air pollution. Summary of the invention

[0004] In order to solve the problem of solvent volatilization generated during the curing process of the hot stamping adhesive and at the same time ensure good bonding strength between the hot stamping pattern and the substrate, the first aspect of the present invention provides a UV-curable hot stamping adhesive, and the preparation raw materials include, by weight: 20-40 parts of modified acrylate resin, 25-35 parts of active diluent, 10-20 parts of functional resin, 5-10 parts of filler, 1-4 parts of initiator, and 0.1-0.3 parts of dispersant.

[0005] As a preferred embodiment, the modified acrylate resin is selected from one or a combination of modified polyester acrylate, modified epoxy acrylate, polyurethane modified acrylate, silicon modified acrylate, and fluorine modified acrylate.

[0006] As a preferred embodiment, the functionality of the modified polyester acrylate is 1-6, and the modified polyester acrylate is a combination of modified polyester acrylates with different viscosities.

[0007] As a preferred embodiment, the modified polyester acrylate includes modified polyester acrylate I and modified polyester acrylate II. The modified polyester acrylate I is a difunctional polyester acrylate with a viscosity of 3000-8000 cps at 60°C. The modified polyester acrylate II is a tetrafunctional polyester acrylate with a viscosity of 1000-3000 cps at 25°C.

[0008] As a preferred embodiment, the weight ratio of the modified polyester acrylate I to the modified polyester acrylate II is 1:(0.2-0.4).

[0009] As a preferred embodiment, the modified polyester acrylate I is selected from one or a combination of Haohui HT7004 and YH7203. The modified polyester acrylate II is selected from one or a combination of Shanghai Santong's SP277, SP280, SP283, and SP236.

[0010] As a preferred embodiment, the functionality of the modified epoxy acrylate is 1-4, and the viscosity of the modified epoxy acrylate at 60° C. is 900-2000 cps.

[0011] As a preferred embodiment, the modified epoxy acrylate is selected from one or a combination of Miramer's PE230, EA2253, Haohui's SU322, Shanghai Santong's ST603, and Covestro's AgiSyn 3051.

[0012] As a preferred embodiment, the polyurethane modified acrylate is an aliphatic polyurethane acrylate with a functionality of 2-4 and a viscosity of 1000-5000 cps at 60°C.

[0013] As a preferred embodiment, the polyurethane modified acrylate is selected from one or a combination of Guangzhou Songda SD7508, SD7101, and SD1000.

[0014] As a preferred embodiment, the modified acrylate resin is a combination of modified polyester acrylate, modified epoxy acrylate and polyurethane modified acrylate.

[0015] As a preferred embodiment, the modified acrylate resin is a combination of modified polyester acrylate, modified epoxy acrylate and polyurethane modified acrylate, with a weight ratio of (10-20): (6-10): (6-10).

[0016] The polyester acrylate includes a low-viscosity tetrafunctional polyester acrylate and a high-viscosity difunctional polyester acrylate, which work together to increase the toughness of the coating and avoid peeling and slag problems during the rolling or hot stamping process. The reason may be that the low-viscosity tetrafunctional polyester acrylate has a high reactivity, and the macromolecules formed after UV curing with the high-viscosity difunctional polyester acrylate are distributed between the pre-dissolved functional resins, and form a certain degree of cross-linked interpenetrating network with other acrylate oligomers, reducing the hardness of the high-functional polyester acrylate and increasing the toughness of the coating, thereby avoiding the brittleness, peeling and slag problems during the processing. The applicant further found that the introduction of polyurethane acrylate with a functionality of 2-4 can further improve the adhesion between the coating and the plating layer. The reason may be that the multifunctional polyurethane acrylate contains a variety of polar or non-polar groups, which has better adhesion to the plating layer, and the hydrogen bonds on the surface of the plating layer also have a certain hydrogen bonding effect with the surface of the polyurethane acrylate, forming a suitable cohesive force, improving the solidity and fineness of the hot stamping.

[0017] As a preferred embodiment, the active diluent is an acrylate active diluent, and the acrylate active diluent is selected from one or a combination of β-hydroxyethyl methacrylate, isobornyl acrylate, β-carboxyethyl acrylate, tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, methacrylate, and phosphate acrylate.

[0018] As a preferred embodiment, the active diluent is a combination of tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, and phosphate acrylate, and the weight ratio of the tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, and phosphate acrylate is (1-2): (1-2): 0.1.

[0019] In this application, a combination of tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, and phosphate acrylate is used as an active diluent to improve the compatibility of acrylic resin in the system, avoid the introduction of organic solvents, and prevent the volatilization of solvents during the hot stamping process. The applicant further found that the introduction of phosphate acrylate improves the adhesion between the hot stamping coating and the hot stamping foil substrate, especially for thermoplastic surfaces, and the improvement effect is significant.

[0020] As a preferred embodiment, the functional resin is a combination of chlorinated paraffin and methyl methacrylate copolymer. Further preferably, the chlorinated paraffin is chlorinated paraffin 70, the glass transition temperature of the methyl methacrylate copolymer is 40-80°C, the acid value is 2-6 mgKOH / g; the weight average molecular weight is 6000-20000Da. Preferably, the methyl methacrylate copolymer is selected from Covestro NeoCryl B-302, Taiwan Province AR-585, Liaoning Tricyclic Resin A-54 or a combination of several thereof.

[0021] As a preferred embodiment, the weight ratio of the chlorinated paraffin and the methyl methacrylate copolymer is (2-3): (0.5-1).

[0022] As a preferred embodiment, the weight ratio of the chlorinated paraffin and the methyl methacrylate copolymer is (2.1-3): (0.8-1).

[0023] As a preferred embodiment, the weight ratio of the chlorinated paraffin and the methyl methacrylate copolymer is 2.5:0.9.

[0024] The present invention adopts a combination of chlorinated paraffin and methyl methacrylate copolymer as a functional resin, which can improve the compatibility effect of the system and increase the cohesion of the system. The molecular structure of the methyl methacrylate copolymer is relatively large, which can reduce the shrinkage of the hot stamping coating after heating and curing, improve the adhesion to the hot stamping foil, and reduce the cross-linking density between the acrylate resins, so that the hot stamping pattern is clearer and the slitting effect after the hot stamping glue is formed into a film is improved.

[0025] As a preferred embodiment, the oil absorption of the filler is 100-220m 2 / g, particle size is 1-10μm.

[0026] As a preferred embodiment, the filler is selected from one or a combination of silicon dioxide, talc, aluminum stearate, and calcium stearate.

[0027] As a preferred embodiment, the filler is surface-treated silica, which has a good dispersion effect in the system, and the silica with a particle size of 1-10 μm can balance the surface tension on both sides of the aluminum coating layer due to coating, and 100-220 μm 2 / g of oil absorption will not cause the hot stamping adhesive to stick back, thereby improving the slitting effect after curing.

[0028] As a preferred embodiment, the initiator is a composite photoinitiator, selected from one or a combination of STCure-184, STCure-1173, and STCure-907 of Shanghai Santong.

[0029] As a preferred embodiment, the dispersant is silane coupling agent kh560.

[0030] A second aspect of the present invention provides a method for preparing a UV-curable hot stamping adhesive, comprising the following steps:

[0031] (1) Mix the active diluent and the functional resin, heat and stir at 40-70°C for 2-3 hours to obtain a pre-dissolved functional resin;

[0032] (2) Then add the modified acrylic resin to the pre-dissolved functional resin and continue stirring for 3-4 hours;

[0033] (3) Continue to add filler, initiator, and dispersant, stir at 300-500 rpm for 0.5-1 h, then stir at 600-900 rpm for 2-3 h, let stand for 2-3 h, and filter the material.

[0034] A third aspect of the present invention provides a method for applying a UV-curable hot stamping adhesive, comprising the following steps:

[0035] (1) Heat the UV-curable hot stamping adhesive to 35-45°C and apply it to the hot stamping foil at a coating amount of 1-1.5 g / m 2 ;

[0036] (2) UV curing for 3-10 seconds, rewinding, UV irradiation energy is 150-350mj / cm², and the film roll after hot stamping is placed at room temperature for 24-48 hours.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] (1) The UV-curable hot stamping adhesive of the present invention uses low-viscosity tetrafunctional polyester acrylate and high-viscosity difunctional polyester acrylate to work together with polyurethane acrylate with a functionality of 2-4, which can increase the toughness of the coating and avoid peeling and slag problems during the winding or hot stamping process.

[0039] (2) The UV-curable hot stamping adhesive of the present invention uses a polyurethane acrylate with a functionality of 2-4 and an epoxy acrylate with a viscosity of 900-2000 cps to improve the adhesion between the hot stamping layer and the hot stamping foil substrate.

[0040] (3) The UV-curable hot stamping adhesive of the present invention uses tripropylene glycol diacrylate, 1,6-hexanediol diacrylate and phosphate acrylate as active diluents, thereby avoiding the introduction of organic solvents and the problem of solvent volatilization during the hot stamping process, and is green and safe. DETAILED DESCRIPTION

[0041] Example 1

[0042] A UV-curable hot stamping adhesive comprises the following raw materials in parts by weight: 30 parts of modified acrylate resin, 30 parts of active diluent, 15 parts of functional resin, 8 parts of filler, 3 parts of initiator and 0.2 parts of dispersant.

[0043] The modified acrylate resin is a combination of modified polyester acrylate, modified epoxy acrylate and polyurethane modified acrylate, with a weight ratio of 15:8:8.

[0044] The modified polyester acrylate is a combination of modified polyester acrylate I and modified polyester acrylate II, with a weight ratio of 1:0.3, wherein the modified polyester acrylate I is a difunctional polyester acrylate with a viscosity of 8000 cps at 60°C, purchased from Guangdong Haohui New Materials Co., Ltd., model number YH7203. The modified polyester acrylate II is a tetrafunctional polyester acrylate with a viscosity of 1000 cps at 25°C, purchased from Dongguan Santong Materials Technology Co., Ltd. & R&D Application Center, model number SP280.

[0045] The functionality of the modified epoxy acrylate is 2, the viscosity of the modified epoxy acrylate at 60° C. is 900 cps, and it is purchased from Guangdong Haohui New Materials Co., Ltd., and the model is SU322.

[0046] The polyurethane modified acrylate is an aliphatic polyurethane acrylate with a functionality of 2 and a viscosity of 1000 cps at 60° C. It is purchased from Guangzhou Songda New Material Technology Co., Ltd. and the model number is SD7101.

[0047] The active diluent is a combination of tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, and phosphate acrylate, with a weight ratio of 1.5:1.5:0.1.

[0048] The functional resin is a combination of chlorinated paraffin and methyl methacrylate copolymer, with a weight ratio of 2.5:0.75. The chlorinated paraffin is chlorinated paraffin 70, and the methyl methacrylate copolymer is purchased from Covestro, model NeoCryl B-302.

[0049] The filler is silicon dioxide, and the oil absorption is 100-220m 2 / g, particle size is 3-7μm, purchased from Grace, model number is Cp48441.

[0050] The initiator is a composite photoinitiator purchased from Dongguan Santong Material Technology Co., Ltd. & R&D Application Center, model number STCure-184.

[0051] The dispersant is silane coupling agent kh560.

[0052] A method for preparing a UV-curable hot stamping adhesive comprises the following steps:

[0053] (1) Mix the active diluent and the functional resin, heat and stir at 60°C for 2.5 hours to obtain the pre-dissolved functional resin;

[0054] (2) Then add the modified acrylic resin to the pre-dissolved functional resin and continue stirring for 3.5 hours;

[0055] (3) Continue to add filler, initiator, and dispersant, stir at 400 rpm for 0.5 h, then stir at 800 rpm for 2 h. After standing for 3 h, filter the material.

[0056] A method for applying a UV-curable hot stamping adhesive comprises the following steps:

[0057] (1) Heat the UV-curable hot stamping adhesive to 40°C and apply it to the hot stamping foil at a viscosity of 100-300 cps. The coating amount is 1.25 g / m 2 ;

[0058] (2) UV curing for 5 seconds, rewinding, UV irradiation energy is 250mj / cm², and the film roll after hot stamping is placed at room temperature for 48 hours.

[0059] Example 2

[0060] A UV-curable hot stamping adhesive comprises the following raw materials in parts by weight: 40 parts of modified acrylate resin, 35 parts of active diluent, 20 parts of functional resin, 10 parts of filler, 4 parts of initiator and 0.3 parts of dispersant.

[0061] The modified acrylate resin is a combination of modified polyester acrylate, modified epoxy acrylate and polyurethane modified acrylate, with a weight ratio of 20:10:10.

[0062] The modified polyester acrylate is a combination of modified polyester acrylate I and modified polyester acrylate II, with a weight ratio of 1:0.3, wherein the modified polyester acrylate I is a difunctional polyester acrylate with a viscosity of 8000 cps at 60°C, purchased from Guangdong Haohui New Materials Co., Ltd., model number YH7203. The modified polyester acrylate II is a tetrafunctional polyester acrylate with a viscosity of 1000 cps at 25°C, purchased from Dongguan Santong Materials Technology Co., Ltd. & R&D Application Center, model number SP280.

[0063] The functionality of the modified epoxy acrylate is 2, the viscosity of the modified epoxy acrylate at 60° C. is 900 cps, and it is purchased from Guangdong Haohui New Materials Co., Ltd., and the model is SU322.

[0064] The polyurethane modified acrylate is an aliphatic polyurethane acrylate with a functionality of 2 and a viscosity of 1000 cps at 60° C. It is purchased from Guangzhou Songda New Material Technology Co., Ltd. and the model number is SD7101.

[0065] The active diluent is a combination of tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, and phosphate acrylate, with a weight ratio of 1.5:2:0.1.

[0066] The functional resin is a combination of chlorinated paraffin and methyl methacrylate copolymer, with a weight ratio of 3: 1. The chlorinated paraffin is chlorinated paraffin 70, and the methyl methacrylate copolymer is purchased from Covestro, with a model of NeoCryl B-302.

[0067] The filler is silicon dioxide, and the oil absorption is 100-220m 2 / g, particle size is 3-7μm, purchased from Grace, model is NeoCryl B-302.

[0068] The initiator is a composite photoinitiator purchased from Dongguan Santong Material Technology Co., Ltd. & R&D Application Center, model number STCure-184.

[0069] The dispersant is silane coupling agent kh560.

[0070] The preparation and application methods of a UV-curable hot stamping adhesive are the same as those in Example 1.

[0071] Example 3

[0072] A UV-curable hot stamping adhesive and a preparation and application method thereof. The specific steps are the same as those in Example 1, except that the modified polyester acrylate is modified polyester acrylate I.

[0073] Example 4

[0074] A UV-curable hot stamping adhesive and a preparation and application method thereof. The specific steps are the same as those in Example 1, except that the modified acrylate resin is a combination of modified polyester acrylate and modified epoxy acrylate, with a weight ratio of 15:10.

[0075] Example 5

[0076] A UV-curable hot stamping adhesive and a preparation and application method thereof, wherein the specific steps are the same as those of Example 1, except that the active diluent is a combination of tripropylene glycol diacrylate and 1,6-hexanediol diacrylate in a weight ratio of 1:1.

[0077] Performance Testing

[0078] The hot stamping performance of the coated sample was tested using a pneumatic hot stamping machine. The present invention uses a hot stamping machine model LZ-320 from Zhejiang Wenzhou Liyi Machinery Factory. The instrument is set to be an instrument model LZ-320 from Zhejiang Wenzhou Liyi Machinery Factory. The test setting temperature is 100-120°C, the hot stamping time is 0.1 second, and the hot stamping is performed manually after the pressure is stable. After the hot stamping, the hot stamping pattern left on the substrate is observed.

[0079] (1) Hot stamping area: Observe the overall hot stamping pattern and use the percentage of the effective area of ​​hot stamping to represent the hot stamping area of ​​the powder foil, with 100% being the best.

[0080] (2) Cutting performance: Observe the grid of the hot stamping pattern, and use the grade of the clear grid to represent the hot stamping cutting performance. The grid with a side length of 0.15 mm is recorded as grade A, the grid with a side length of 0.33 mm is recorded as grade B, the grid with a side length of 0.56 mm is recorded as grade C (qualified grade), the grid with a side length of 1.36 mm is recorded as grade D, and the grid with a side length of 2.5 mm is recorded as grade E.

[0081] (3) Adhesion fastness: To test the adhesion fastness of hot stamping, stick 3M test tape to the hot stamping pattern, roll it back and forth horizontally with a 2kg roller three times, tear off the test tape, and observe the hot stamping pattern still left on the substrate. The percentage of the remaining pattern area is used to express the adhesion fastness (100% means that the tape has not removed any hot stamping pattern, and the adhesion fastness is the best; 0% means that the tape has removed all the hot stamping pattern, and the adhesion fastness is the worst.)

[0082] The test results are shown in Table 1.

[0083] Table 1

[0084]

Claims

1. A UV-curable hot stamping adhesive, characterized in that: The raw materials for preparation include, by weight: 20-40 parts of modified acrylate resin, 25-35 parts of active diluent, 10-20 parts of functional resin, 5-10 parts of filler, 1-4 parts of initiator, and 0.1-0.3 parts of dispersant; The modified acrylate resin is a combination of modified polyester acrylate, modified epoxy acrylate and polyurethane modified acrylate; The modified polyester acrylate includes modified polyester acrylate I and modified polyester acrylate II, wherein the modified polyester acrylate I is a difunctional polyester acrylate having a viscosity of 3000-8000 cps at 60° C.; the modified polyester acrylate II is a tetrafunctional polyester acrylate having a viscosity of 1000-3000 cps at 25° C.; The functionality of the modified epoxy acrylate is 1-4, and the viscosity of the modified epoxy acrylate at 60° C. is 900-2000 cps; The polyurethane modified acrylate is an aliphatic polyurethane acrylate with a functionality of 2-4 and a viscosity of 1000-5000 cps at 60°C; The active diluent is a combination of tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, and phosphate acrylate; The oil absorption of the filler is 100-220m 2 / g, particle size is 1-10μm.

2. The UV-curable hot stamping adhesive according to claim 1, characterized in that: The filler is selected from one or a combination of silicon dioxide, talc, aluminum stearate, and calcium stearate.

3. A method for preparing the UV-curable hot stamping adhesive according to any one of claims 1 to 2, characterized in that: The following steps are involved: (1) Mix the active diluent and the functional resin, heat and stir at 40-70°C for 2-3 hours to obtain a pre-dissolved functional resin; (2) Then add the modified acrylic resin to the pre-dissolved functional resin and continue stirring for 3-4 hours; (3) Continue to add filler, initiator, and dispersant, stir at 300-500 rpm for 0.5-1 h, then stir at 600-900 rpm for 2-3 h, let stand for 2-3 h, and filter the material.

4. A method for applying the UV-curable hot stamping adhesive according to any one of claims 1 to 2, characterized in that: The following steps are involved: (1) Heat the UV-curable hot stamping adhesive to 35-45°C and apply it to the hot stamping foil at a coating amount of 1-1.5 g / m 2 ; (2) UV curing for 3-10 seconds, rewinding, UV irradiation energy is 150-350mj / cm², and the film roll after hot stamping is placed at room temperature for 24-48 hours.

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