Ultraviolet-curable shading black glue with high absorbance and preparation method thereof

Abstract

The invention relates to the technical field of adhesives, in particular to ultraviolet-curable shading black glue with high absorbance and a preparation method of the ultraviolet-curable shading black glue. Comprising the following raw material components in parts by weight: 40-50 parts of polyurethane modified acrylate resin; 45-55 parts of a basic acrylate monomer or a functional acrylate monomer; 0.2 to 0.6 part of a photoinitiator; and 1-4 parts of a black filler. The absorption wavelength of the photoinitiator is 250-400 nm, the black filler is carbon black, light shading or appearance treatment can be carried out on a device, rapid batch curing can be achieved, and meanwhile the strength and long-term use stability of the glue are guaranteed.

Description

Technical Field

[0001] This invention relates to the field of adhesive technology, specifically to a light-blocking black adhesive that can be cured by ultraviolet light and has high light absorption, and its preparation method. Background Technology

[0002] With the development of electronic information technology, UV-curable adhesives have been widely used in various industries due to their advantages such as fast curing speed, environmental friendliness, and low energy consumption. UV-curable adhesives have good bonding strength, transparency, and water resistance; they do not exhibit internal stress cracking after curing; and they can be easily applied using automated dispensing or screen printing.

[0003] However, traditional UV-curable adhesives have some limitations in certain special applications. For example, in situations where a black opaque effect is required, carbon black or black pigment is usually added to the adhesive. However, this makes it difficult for UV light to reach the bottom, thus affecting the curing reaction of the coating. Only the coating near the surface can be cured into a film.

[0004] Currently, black UV adhesives and UV-changing black adhesives on the market generally suffer from a contradiction between light-blocking performance and curing depth. Although some products use photochromic dyes to achieve adhesive curing, these products are still unsatisfactory in long-term humid heat resistance and applications with rapid high and low temperature changes, and their bond strength and bulk strength often need improvement. In addition, existing black UV adhesives are prone to reversible photo-blackening after thermal shock and 240 hours of double 85 exposure, resulting in insufficient light-blocking and poor imaging.

[0005] As display technology advances towards extreme thinness and lightness, more stringent requirements are being placed on the materials that make up the display. In the fabrication of composite optical films, the selection of efficient and environmentally friendly adhesives has become a major challenge. Currently, the high cost and high viscosity of bonding adhesives limit their direct application; they must be diluted to a suitable viscosity by adding organic solvents to achieve roll-to-roll coating. This process also increases heat consumption due to solvent evaporation.

[0006] Therefore, there is an urgent need to develop a black UV adhesive that can be prepared without high temperature and high humidity, so as to achieve light shielding or appearance treatment of devices, and to enable rapid batch curing while ensuring the strength and long-term stability of the adhesive.

[0007] To address the aforementioned problems, this invention provides a light-blocking black adhesive that can be cured under ultraviolet light and has high light absorption, as well as a method for preparing the same. Summary of the Invention

[0008] The purpose of this invention is to provide a light-blocking black adhesive that can be cured by ultraviolet light and has high light absorption, and a method for preparing the same, so as to solve the problems mentioned in the background art.

[0009] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a light-blocking black adhesive that can be cured by ultraviolet light and has high light absorption, comprising the following raw materials in parts by weight: 40-50 parts of polyurethane-modified acrylate resin; 45-55 parts of acrylate monomer or propylene modifier; Photoinitiator 0.2~0.6 parts; 1-4 parts of black filler; The photoinitiator has an absorption wavelength of 250~400nm, and the black filler is carbon black.

[0010] In a more optimized manner, the polyurethane modified acrylate resin is selected from at least one of the following: Fengjin FJ-578-2, Daimas BRC-554, Changxing DR-U084, Runao 5806, and Shengkainuo EVT-004.

[0011] More preferably, the acrylate monomer or propylene modifier is selected from at least one of dicyclopentadienyl acrylate, isobornyl acrylate, 4-tert-butylcyclohexyl acrylate, 3,3,5-trimethylcyclohexyl acrylate, 2-phenoxyethyl acrylate, tetrahydrofuran acrylate, lauryl acrylate, phosphate acrylate, acryloylmorpholine, and N,N-dimethylacrylamide.

[0012] More optimally, the photoinitiator is selected from at least one of 1-hydroxycyclohexylphenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0013] Ideally, the elastic modulus of the adhesive is 160-200 MPa and the elongation at break is ≥100%.

[0014] Ideally, the adhesive has a glass pull-out strength ≥3MPa and a glass peel strength ≥14N / cm.

[0015] Ideally, the viscosity of the adhesive is 900~1100 mPa·s, and the hardness (Shore A type) is 20~40.

[0016] Ideally, the water absorption rate of the adhesive is ≤1.0%, and the tensile strength is ≥15MPa.

[0017] In a more optimized manner, the adhesive achieves an OD value of 2.0 in the visible light range at a film thickness of 50 micrometers and an OD value of 3.0 in the visible light range at a film thickness of 100 micrometers.

[0018] This invention also provides a method for preparing a UV-curable, light-blocking black adhesive with high absorbance, comprising the following steps: S1, take a certain amount of acrylate resin and a certain amount of acrylic monomer or hybrid acrylic monomer, stir and mix them at 25~35℃ for 3~5 min to obtain a mixture; S2, add a measured amount of photoinitiator and black filler to the mixture and continue stirring for 2-3 minutes; S3. The mixture obtained from stirring is filtered, poured, and encapsulated to obtain pure UV-curable black acrylic adhesive.

[0019] Compared with the prior art, the beneficial effects achieved by the present invention are: This invention develops a pure UV-curable black acrylic adhesive by selecting a photoinitiator with high curing efficiency and highly active acrylic resin and monomers. This overcomes the problem that traditional black UV adhesives require the addition of carbon black or black pigment, which makes it difficult for UV light to reach the bottom, and achieves overall curing.

[0020] The black acrylic adhesive prepared by this invention can achieve an OD value of 2 in the visible light range when the film thickness is 50 micrometers and an OD value of 3 in the visible light range when the film thickness is 100 micrometers, which significantly improves the light-shielding performance and solves the problem of the contradiction between light-shielding performance and curing depth in the prior art.

[0021] The black acrylic adhesive prepared by this invention has low viscosity and water absorption, avoiding the problem of traditional black UV adhesives requiring dilution with organic solvents. This not only reduces production costs but also reduces the heat energy consumption generated during solvent evaporation.

[0022] The black acrylic adhesive prepared by this invention has moderate hardness, Tg, tensile strength, elastic modulus and elongation at break, and excellent pull-out strength and peel strength to glass, which significantly improves the overall performance and service life of the product.

[0023] The black acrylic adhesive prepared by this invention exhibits excellent stability in long-term damp heat resistance and in application scenarios with rapid changes in high and low temperatures, effectively solving the problem of poor stability of black UV adhesives in these environments in the prior art. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] This invention provides a UV-curable black adhesive, comprising the following raw material components in parts by weight: 40-50 parts of polyurethane-modified acrylate resin; 45-55 parts of basic acrylate monomer or functional acrylate monomer; 0.2-0.6 parts of photoinitiator; and 1-4 parts of black filler. The photoinitiator has an absorption wavelength of 250-400 nm, and the black filler is carbon black.

[0026] This invention uses specific types and amounts of components, enabling the adhesive, which appears black, to undergo a polymerization reaction under ultraviolet light, and resulting in the adhesive having excellent light absorption after curing.

[0027] In this invention, the acrylate resin is selected from one or more of the following: Fengjin FJ-578-2, Daimas BRC-554, Changxing DR-U084, Runao 5806, and Shengkainuo EVT-004.

[0028] The acrylate monomer or propylene modifier is selected from one or more of the following: dicyclopentadienyl acrylate, isobornyl acrylate, 4-tert-butylcyclohexyl acrylate, 3,3,5-trimethylcyclohexyl acrylate, 2-phenoxyethyl acrylate, tetrahydrofuran acrylate, lauryl acrylate, phosphate acrylate, acrylmorpholine, and N,N-dimethylacrylamide.

[0029] The photoinitiator is selected from at least one of 1-hydroxycyclohexylphenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0030] The preparation method of the UV-curable black adhesive includes the following steps: taking a certain amount of acrylate resin and a certain amount of acrylic monomer or hybrid acrylic monomer, stirring and mixing at 25-35℃ for 3-5 minutes to obtain a mixture; taking a certain amount of photoinitiator and black filler and adding them to the mixture, and continuing to stir for 2-3 minutes; filtering, pouring and encapsulating the mixture to obtain pure UV-curable black acrylate adhesive.

[0031] Based on the above raw material ratios and preparation steps, this invention provides several examples and comparative examples to verify the performance of the obtained UV-curable black acrylic adhesive. The specific formulations are shown in Table 1.

[0032] Table 1. Raw material formulation of the adhesive in each embodiment and comparative example.

[0033] In this invention, isobornyl acrylate (IBOA) was SR506NS, tetrahydrofuran acrylate (THFA) was SR285NS, 2-phenoxyethyl acrylate (PHEA) was SR339NS, 1,6-hexanediol diacrylate (HDDA) was SR238NS, trimethylolpropane triacrylate (TMPTA) was SR351NS, and phosphate acrylate was SR9051NS, all purchased from Sartoma; carbon black was purchased from Cabot.

[0034] The UV-curable black adhesives obtained in the examples and comparative examples were subjected to performance tests as follows: Viscosity: The viscosity of the liquid black adhesive was measured using a rotational viscometer from TA Instruments at an ambient temperature of 25°C using the rotor head.

[0035] Absorbance values: The absorbance of the black film was measured using a ThermoFisher Scientific UV-Vis spectrophotometer in the wavelength range of 400nm-800nm.

[0036] Tensile strength: The tensile strength of the black adhesive film was tested using an Instron universal tensile testing machine. During the test, the force sensor was set to an upper limit of 1000N, and the mechanical tensile speed was 100mm / min.

[0037] Elastic modulus: The elastic modulus of the black film was tested using an Instron universal tensile testing machine and an Instron video extensometer. During the test, the force sensor was set to an upper limit of 1000 N, and the mechanical tensile speed was 100 mm / min.

[0038] Elongation at break: The elongation at break of the black film was tested using an Instron universal tensile testing machine and an Instron video elongator. During the test, the force sensor was set to an upper limit of 1000 N, and the mechanical tensile speed was 100 mm / min.

[0039] Glass transition temperature: The glass transition temperature of the black film was measured using DMA from TA Instruments.

[0040] Hardness: A D-type Shore hardness tester was used to test the instantaneous hardness of the black adhesive film after pressing for 15 seconds on a 6mm thick sample. Since a single layer of adhesive film is relatively thin, multiple layers are generally stacked to achieve a total thickness of 6mm before testing.

[0041] Water absorption rate: Select a black adhesive film with a thickness of 100µm and a size of 2cm × 1cm. Immerse the sample in boiling water for 48 hours. Measure the mass m1 of the sample before immersion and the mass m2 of the sample after immersion. Calculate the water absorption rate corresponding to the difference in sample mass before and after immersion using the formula: Water absorption rate = (m2 - m1) / m1 × 100%.

[0042] Pull-out strength: The pull-out strength of the black adhesive film was tested using a Kinsgel universal tensile testing machine. The test substrate was glass, and during the test, the force sensor was set to an upper limit of 500N, and the mechanical tensile speed was 10mm / min.

[0043] Peel strength: The peel strength of the black adhesive film at 90° and 180° was tested using an Instron universal tensile testing machine. The test substrate was glass, and during the test, the force sensor was set to an upper limit of 1000N, and the mechanical tensile speed was 300mm / min.

[0044] Curing method: The black adhesive in this experiment was polymerized using ultraviolet light-initiated polymerization. Ultraviolet curing conditions: Light intensity 340 mW / cm². 2 The illumination time is 8 seconds.

[0045] The test results are shown in Table 2: Table 2 Performance test results of the adhesive in each embodiment and comparative example

[0046] As shown in Table 2, the black adhesive prepared with the raw material formulation of Example 2 has the best overall performance and high light absorption. At the same time, the tensile strength, elastic modulus and elongation at break of Example 2 are all at a high level, and the water absorption is low. It can be seen that the black adhesive prepared by the present invention has excellent stability in long-term damp heat resistance and application scenarios with rapid changes in high and low temperatures.

[0047] The above description is merely an optional embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made using the contents of the present invention under the inventive concept of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A UV-curable, light-blocking black adhesive with high light absorption, characterized in that, The raw materials include the following parts by weight: 40-50 parts of polyurethane-modified acrylate resin; 45-55 parts of acrylate monomer or propylene modifier; Photoinitiator 0.2~0.6 parts; 1-4 parts of black filler; The photoinitiator has an absorption wavelength of 250~400nm, and the black filler is carbon black.

2. The UV-curable, high-absorbency, light-blocking black adhesive according to claim 1, characterized in that: The polyurethane modified acrylate resin is selected from at least one of the following: Fengjin FJ-578-2, Daimas BRC-554, Changxing DR-U084, Runao 5806, and Shengkainuo EVT-004.

3. The UV-curable, high-absorbency, light-blocking black adhesive according to claim 1, characterized in that: The acrylate monomer or propylene modifier is selected from at least one of dicyclopentadienyl acrylate, isobornyl acrylate, 4-tert-butylcyclohexyl acrylate, 3,3,5-trimethylcyclohexyl acrylate, 2-phenoxyethyl acrylate, tetrahydrofuran acrylate, lauryl acrylate, phosphate acrylate, acryloylmorpholine, and N,N-dimethylacrylamide.

4. The UV-curable, high-absorbency, light-blocking black adhesive according to claim 1, characterized in that: The photoinitiator is selected from at least one of 1-hydroxycyclohexylphenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

5. The UV-curable, high-absorbency, light-blocking black adhesive according to claim 1, characterized in that: The elastic modulus of the adhesive is 160-200 MPa, and the elongation at break is ≥100%.

6. The UV-curable, high-absorbency, light-blocking black adhesive according to claim 1, characterized in that: The adhesive has a glass pull-out strength ≥3MPa and a glass peel strength ≥14N / cm.

7. The UV-curable, high-absorbency, light-blocking black adhesive according to claim 1, characterized in that: The viscosity of the adhesive is 900~1100 mPa·s, and the hardness (Shore A type) is 20~40.

8. The UV-curable, high-absorbency, light-blocking black adhesive according to claim 1, characterized in that: The adhesive has a water absorption rate of ≤1.0% and a tensile strength of ≥15MPa.

9. The UV-curable, high-absorbency, light-blocking black adhesive according to claim 1, characterized in that: The adhesive has an OD value of 2.0 in the visible light range at a film thickness of 50 micrometers and an OD value of 3.0 in the visible light range at a film thickness of 100 micrometers.

10. A method for preparing a UV-curable, light-blocking black adhesive with high absorbance, characterized in that, Includes the following steps: S1, take a certain amount of acrylate resin and a certain amount of acrylic monomer or hybrid acrylic monomer, stir and mix them at 25~35℃ for 3~5 min to obtain a mixture; S2, add a measured amount of photoinitiator and black filler to the mixture and continue stirring for 2-3 minutes; S3. The mixture obtained from stirring is filtered, poured, and encapsulated to obtain pure UV-curable black acrylic adhesive.

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