Polyurethane acrylic photosensitive resin, preparation method thereof and application of polyurethane acrylic photosensitive resin in flexible display screen

Abstract

The invention provides polyurethane acrylic photosensitive resin, a preparation method thereof and application of the polyurethane acrylic photosensitive resin in a flexible display screen, and belongs to the field of high polymer materials. The preparation raw materials of the polyurethane acrylic photosensitive resin comprise diisocyanate, a macromolecular chain extender, a micromolecular chain extender, a first end-capping reagent, a second end-capping reagent, a catalyst, a polymerization inhibitor and an active diluent, the macromolecular chain extender is polyester polyol, the micromolecular chain extender is micromolecular dihydric alcohol, the first end-capping reagent is polyether polyol, and the second end-capping reagent is polyether polyol. The first end-capping reagent is acrylic ester containing hydroxyl, and the second end-capping reagent is alkoxy silane containing reactive hydrogen. According to the polyurethane acrylic photosensitive resin disclosed by the invention, a flexible display screen can have high-temperature bending resistance and is free of creases when being bent.

Description

Technical Field

[0001] The present invention belongs to the field of polymer materials, and relates to a polyurethane acrylate photosensitive resin, a preparation method thereof, and an application thereof in a flexible display screen. Background Art

[0002] In recent years, the demand for foldable screens has been increasing, and more and more people have started to choose to use foldable screen devices such as mobile phones and tablets. At the same time, with the upgrade of product performance, higher and higher requirements have been put forward. For example, during the long-term use of foldable screen devices, when high-function programs are running, accompanied by heat release, the internal temperature may be continuously above 50 °C for a long time. In this case, when folding and using repeatedly, faint creases may appear inside the screen, and it is difficult to eliminate them. Over time, it will affect the user's visual perception of the screen.

[0003] Therefore, in this field, it is expected to solve the above-mentioned technical problems so that the foldable screen has the effect of not generating creases when folded, especially under high-temperature conditions, and has the effect of being resistant to folding. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a polyurethane acrylate photosensitive resin, a preparation method thereof, and an application thereof in a flexible display screen. The polyurethane acrylate photosensitive resin of the present invention can endow the flexible display screen with high-temperature folding resistance and no creases when folded.

[0005] To achieve this purpose, the present invention adopts the following technical solutions:

[0006] On the one hand, the present invention provides a polyurethane acrylate photosensitive resin. The raw materials for preparing the polyurethane acrylate photosensitive resin include diisocyanate, macromolecular chain extender, small-molecule chain extender, first capping agent, second capping agent, catalyst, inhibitor, and active diluent. The macromolecular chain extender is polyester polyol, the small-molecule chain extender is small-molecule diol, the first capping agent is acrylate containing hydroxyl group, and the second capping agent is alkoxysilane containing active hydrogen.

[0007] In the present invention, the polyurethane acrylate photosensitive resin prepared by using the above raw materials can be used for the photocuring coating of the flexible display screen, so that the flexible display screen has high-temperature folding resistance and no creases when folded.

[0008] Preferably, the diisocyanate is one or a combination of at least two of isophthalic diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, or dicyclohexylmethane diisocyanate.

[0009] Preferably, the polyester polyol is a polyester polyol composed of a diacid and a diol. The diacid is selected from any one or a combination of at least two of 1,6-hexanedioic acid, sebacic acid, dodecanedioic acid, or isophthalic acid. The diol is selected from any one or a combination of at least two of 1,4-butanediol, diethylene glycol, ethylene glycol, neopentyl glycol, or isohexylene glycol.

[0010] Preferably, the number-average molecular weight of the polyester polyol is 1000 - 1500, such as 1000, 1100, 1200, 1300, 1400, or 1500. In the present invention, if the number-average molecular weight of the polyester polyol is less than 1000, the desired bending resistance effect cannot be achieved. If the number-average molecular weight of the polyester polyol is greater than 1500, the strength of the polyurethane acrylate photosensitive resin will decrease.

[0011] Preferably, the small molecule diol is one or a combination of at least two of ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, or neopentyl glycol.

[0012] Preferably, the first capping agent is one or a combination of at least two of 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, or 2-hydroxypropyl methacrylate.

[0013] Preferably, the second capping agent is 3-aminopropyltrimethoxysilane and / or 3-aminopropyltriethoxysilane.

[0014] Preferably, the catalyst is selected from dibutyltin dilaurate and / or bismuth laurate.

[0015] Preferably, the inhibitor is selected from BHT (2,6-di-tert-butyl-4-methylphenol) or MEHQ (p-methoxyphenol).

[0016] Preferably, the reactive diluent is selected from any one or a combination of at least two of isooctyl acrylate, isobornyl acrylate, isobornyl methacrylate, methyl methacrylate, butyl acrylate, hexanediol diacrylate, neopentyl glycol diacrylate, dipropylene glycol diacrylate, trimethylolpropane triacrylate, or tetrahydrofurfuryl acrylate.

[0017] Preferably, the molar ratio of the diisocyanate to the macromolecular chain extender in the raw materials for preparing the polyurethane acrylate photosensitive resin is 1:(0.80 - 0.85), such as 1:0.80, 1:0.81, 1:0.82, 1:0.83, 1:0.84, or 1:0.85.

[0018] Preferably, the molar ratio of the diisocyanate to the small molecule chain extender in the raw materials for preparing the polyurethane acrylate photosensitive resin is 1:(0.05 - 0.08), such as 1:0.05, 1:0.06, 1:0.07 or 1:0.08.

[0019] Preferably, the molar ratio of the diisocyanate to the first capping agent in the raw materials for preparing the polyurethane acrylate photosensitive resin is 1:(0.05 - 0.06), such as 1:0.05, 1:0.053, 1:0.055, 1:0.057, 1:0.059 or 1:0.06.

[0020] Preferably, the molar ratio of the diisocyanate to the second capping agent in the raw materials for preparing the polyurethane acrylate photosensitive resin is 1:(0.05 - 0.07), such as 1:0.05, 1:0.055, 1:0.058, 1:0.06, 1:0.065, 1:0.068 or 1:0.07.

[0021] Preferably, the dosage of the catalyst in the raw materials for preparing the polyurethane acrylate photosensitive resin is 0.005% - 0.1% of the total mass of the raw materials, such as 0.005%, 0.008%, 0.01%, 0.03%, 0.05%, 0.08% or 0.1%.

[0022] Preferably, the dosage of the inhibitor in the raw materials for preparing the polyurethane acrylate photosensitive resin is 0.1% - 0.2% of the total mass of the raw materials, such as 0.1%, 0.13%, 0.15%, 0.18% or 0.2%.

[0023] Preferably, the dosage of the reactive diluent in the raw materials for preparing the polyurethane acrylate photosensitive resin is the dosage that makes the viscosity of the obtained polyurethane acrylate photosensitive resin reach 21000 - 27000 cps (such as 21000 cps, 22000 cps, 23000 cps, 24000 cps, 25000 cps, 26000 cps or 27000 cps) at 25°C.

[0024] On the other hand, the present invention provides a method for preparing the polyurethane acrylate photosensitive resin as described above, and the preparation method includes the following steps:

[0025] (1) Mix the diisocyanate, the macromolecular chain extender, the catalyst and the inhibitor, and react;

[0026] (2) Add the small molecule chain extender to the reaction system obtained in step (1), and react;

[0027] (3) Add the first capping agent and the second capping agent to the reaction system obtained in step (2), react, and then add the reactive diluent to obtain the polyurethane acrylate photosensitive resin.

[0028] Preferably, the temperature of the reaction in step (1) is 50 - 60°C, such as 50°C, 53°C, 55°C, 58°C or 60°C, and the reaction time is 4 - 8 h, such as 4 h, 5 h, 6 h, 7 h or 8 h.

[0029] Preferably, the temperature of the reaction in step (2) is 70 - 80°C, such as 70°C, 73°C, 75°C, 78°C or 80°C, and the reaction time is 4 - 8 h, such as 4 h, 5 h, 6 h, 7 h or 8 h.

[0030] Preferably, the temperature of the reaction in step (3) is 50 - 60°C, such as 50°C, 53°C, 55°C, 58°C or 60°C, and the reaction time is 1 - 6 h, such as 1 h, 2 h, 3 h, 4 h, 5 h or 6 h.

[0031] Adding the reactive diluent in step (3) makes the viscosity of the polyurethane acrylate photosensitive resin 21000 - 27000 cps at 25°C, such as 21000 cps, 22000 cps, 23000 cps, 24000 cps, 25000 cps, 26000 cps or 27000 cps.

[0032] As a preferred technical solution of the present invention, the preparation method includes the following steps:

[0033] Add the diisocyanate, macromolecular chain extender, catalyst, inhibitor and reactive diluent into a four-necked flask and mix them, and carry out a mixing reaction at 50 - 60°C for 4 h until the system reaches the theoretical isocyanate group content; add the low-molecular-weight chain extender to the reaction system, and carry out a mixing reaction at 70 - 80°C for 4 h until the system reaches the theoretical isocyanate group content; add the first capping agent and the second capping agent to the reaction system, and react for 1 h until the isocyanate group content in the system is consumed to less than 0.1 wt% to obtain the polyurethane acrylate photosensitive resin.

[0034] On the other hand, the present invention provides a polyurethane acrylate photosensitive resin composition, and the polyurethane acrylate photosensitive resin composition includes a polyurethane acrylate photosensitive resin and a photoinitiator.

[0035] Preferably, the addition amount of the photoinitiator in the polyurethane acrylate photosensitive resin composition is 1 - 5% of the total weight of the polyurethane acrylate photosensitive resin composition, such as 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%.

[0036] Preferably, the photoinitiator is selected from any one or a combination of at least two of TPO-L, TMO, 184, 1173, ITX or DETX.

[0037] On the other hand, the present invention provides a photocurable coating for a flexible display screen, which is obtained by photocuring the polyurethane acrylate photosensitive resin composition as described above.

[0038] In the present invention, the photocurable coating for the flexible display screen is obtained by coating the polyurethane acrylate photosensitive resin composition on a substrate and then performing photocuring.

[0039] In the present invention, the substrate is optical glass or flexible glass.

[0040] Preferably, the photocuring is ultraviolet light curing.

[0041] Preferably, the radiation conditions for the ultraviolet light curing are a mercury lamp of 1000 W, a wavelength of 365 nm, a radiation distance of 15 cm, and a radiation energy ≥ 500 mJ / cm 2 .

[0042] On the other hand, the present invention provides the application of the polyurethane acrylate photosensitive resin as described above or the polyurethane acrylate photosensitive resin composition as described above in a flexible circuit board silver paste or a foldable display screen.

[0043] The polyurethane acrylate photosensitive resin of the present invention or the polyurethane acrylate photosensitive resin composition as described above has the properties of high temperature resistance and bending resistance, and is suitable for flexible coatings that need to be bent multiple times in a high temperature environment, such as resins for UV-curable flexible circuit board silver pastes, glass coatings for buffering foldable display screens, etc.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] The polyurethane acrylate photosensitive resin of the present invention can be used for the photocurable coating of a flexible display screen, so that the flexible display screen has the properties of high temperature resistance and bending resistance, and there are no creases after bending. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is the infrared spectrum diagram of the polyurethane acrylate photosensitive resin prepared in Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0047] The technical solutions of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations to the present invention.

[0048] Example 1

[0049] This example provides a polyurethane acrylate photosensitive resin, and the preparation method of the polyurethane acrylate photosensitive resin includes the following steps:

[0050] 1 mol of isophthalic diisocyanate, 0.80 mol of polybutylene adipate (number-average molecular weight of 1000, purchased from Zhejiang Huafeng), 0.1% of the total mass of the raw materials of dibutyltin dilaurate as a catalyst, and 0.1% of the total mass of the raw materials of BHT as a polymerization inhibitor were added to a four-necked flask and mixed, and reacted at 60 °C for 4 h; until the system reached the theoretical isocyanate group content; 0.06 mol of small molecule chain extender 1,4-butanediol was added to the reaction system, and reacted at 70 °C for 4 h until the system reached the theoretical isocyanate group content; 0.05 mol of the first capping agent hydroxyethyl acrylate and 0.05 mol of the second capping agent were added to the reaction system, and reacted for 1 h until the isocyanate group content of the system was consumed to less than 0.1 wt%, and an active diluent (including 30% of isooctyl acrylate and 5% of isobornyl methacrylate based on the total mass of the raw materials) was added to obtain the polyurethane acrylate photosensitive resin, and its viscosity at 25 °C was 23500 cps.

[0051] Figure 1 Figure 4 is the infrared spectrum of the polyurethane acrylate photosensitive resin prepared in Example 1, in which 3300-3500 cm -1 An -OH absorption peak appeared, and 2900-3000 cm -1 An absorption peak of -CH 3 Stretching vibration absorption peak appeared, and at 2100-2400 cm -1 The characteristic absorption peak of "-NCO" did not appear, indicating that the isocyanate group has almost completely reacted. At 1720-1730 cm -1 An absorption peak of the stretching vibration of the carbonyl group (C=O) appeared, and at 1100-1250 cm -1 An absorption peak of the stretching vibration of C-O-C appeared.

[0052] Example 2

[0053] This example provides a polyurethane acrylate photosensitive resin. The preparation method of the polyurethane acrylate photosensitive resin includes the following steps:

[0054] 1 mol of isophthalic diisocyanate, 0.85 mol of poly(butylene phthalate) (number-average molecular weight of 1000, purchased from Zhejiang Huafeng), 0.1% by total mass of the raw materials of dibutyltin dilaurate as a catalyst, and 0.1% by total mass of the raw materials of BHT as a polymerization inhibitor were added to a four-necked flask and mixed. The mixture was reacted at 50 °C for 4 h until the system reached the theoretical isocyanate group content. 0.06 mol of the small molecule chain extender diethylene glycol was added to the reaction system, and the mixture was reacted at 80 °C for 4 h until the system reached the theoretical isocyanate group content. 0.05 mol of the first capping agent 2-hydroxyethyl acrylate and 0.05 mol of the second capping agent 3-aminopropyltrimethoxysilane were added to the reaction system, and the reaction was carried out for 1 h until the isocyanate group content of the system was consumed to less than 0.1 wt%. 5% by total mass of the raw materials of butyl acrylate and 20% by total mass of hexanediol diacrylate were added to obtain the polyurethane acrylate photosensitive resin, and its viscosity at 25 °C was 24800 cps.

[0055] Example 3

[0056] This example provides a polyurethane acrylate photosensitive resin, and the preparation method of the polyurethane acrylate photosensitive resin includes the following steps:

[0057] 1 mol of isophthalic diisocyanate, 0.85 mol of poly(isophthalic acid butylene glycol) (number-average molecular weight of 1500, Guangzhou Haoyi New Materials Technology Co., Ltd.), 0.1% by total mass of the raw materials of dibutyltin dilaurate as a catalyst, and 0.1% by total mass of the raw materials of BHT as a polymerization inhibitor were added to a four-necked flask and mixed. The mixture was reacted at 50 °C for 4 h until the system reached the theoretical isocyanate group content. 0.05 mol of the small molecule chain extender diethylene glycol was added to the reaction system, and the mixture was reacted at 80 °C for 4 h until the system reached the theoretical isocyanate group content. 0.06 mol of the first capping agent 2-hydroxyethyl acrylate and 0.06 mol of the second capping agent 3-aminopropyltrimethoxysilane were added to the reaction system, and the reaction was carried out for 1 h until the isocyanate group content of the system was consumed to less than 0.1 wt%. 3% by total mass of the raw materials of tetrahydrofuran acrylate and 25% by total mass of the raw materials of neopentyl glycol diacrylate were added to obtain the polyurethane acrylate photosensitive resin, and its viscosity at 25 °C was 25800 cps.

[0058] Example 4

[0059] This example provides a polyurethane acrylate photosensitive resin, and the preparation method of the polyurethane acrylate photosensitive resin includes the following steps:

[0060] 1 mol of isophthalic dimethyl diisocyanate, 0.83 mol of neopentyl glycol adipate (number-average molecular weight is 1,500, purchased from Qingdao Yutian Co., Ltd.), bismuth laurate as a catalyst accounting for 0.1% of the total mass of the raw materials, and BHT as a polymerization inhibitor accounting for 0.1% of the total mass of the raw materials were added to a four-necked flask and mixed. The mixture was reacted at 55 °C for 4 h until the system reached the theoretical isocyanate group content. 0.08 mol of small molecule chain extender ethylene glycol was added to the reaction system, and the mixture was reacted at 70 °C for 4 h until the system reached the theoretical isocyanate group content. 0.06 mol of the first capping agent 2-hydroxyethyl methacrylate and 0.07 mol of the second capping agent 3-aminopropyltriethoxysilane were added to the reaction system, and the reaction was carried out for 1 h until the isocyanate group content in the system was consumed to less than 0.1 wt%. 10% of trimethylolpropane triacrylate and 15% of dipropylene glycol diacrylate based on the total mass of the raw materials were added to obtain the polyurethane acrylate photosensitive resin, and its viscosity at 25 °C was 24,300 cps.

[0061] Example 5

[0062] This example provides a polyurethane acrylate photosensitive resin, and the preparation method of the polyurethane acrylate photosensitive resin includes the following steps:

[0063] 1 mol of isophthalic dimethyl diisocyanate, 0.85 mol of isohexyl glycol adipate (number-average molecular weight is 1,000, Guangzhou Haoyi New Materials Technology Co., Ltd.), bismuth laurate as a catalyst accounting for 0.1% of the total mass of the raw materials, and MEHQ as a polymerization inhibitor accounting for 0.1% of the total mass of the raw materials were added to a four-necked flask and mixed. The mixture was reacted at 55 °C for 4 h until the system reached the theoretical isocyanate group content. 0.05 mol of small molecule chain extender ethylene glycol was added to the reaction system, and the mixture was reacted at 70 °C for 4 h until the system reached the theoretical isocyanate group content. 0.06 mol of the first capping agent 2-hydroxypropyl methacrylate and 0.06 mol of the second capping agent 3-aminopropyltriethoxysilane were added to the reaction system, and the reaction was carried out for 1 h until the isocyanate group content in the system was consumed to less than 0.1 wt%. 25% of hexanediol diacrylate based on the total mass of the raw materials was added to obtain the polyurethane acrylate photosensitive resin, and its viscosity at 25 °C was 26,100 cps.

[0064] Example 6

[0065] The difference from Example 1 is only that the polyester polyol is butanediol adipate with a number-average molecular weight of 2,000 (purchased from Shanghai Huide), and the polyurethane acrylate photosensitive resin was prepared, and its viscosity at 25 °C was 59,800 cps.

[0066] Example 7

[0067] The difference from Example 1 is only that the polyester polyol is polybutylene adipate with a number average molecular weight of 800 (purchased from Qingdao Yutian), and a polyurethane acrylate photosensitive resin is prepared, and its viscosity at 25 °C is 19800 cps.

[0068] Comparative Example 1

[0069] The difference from Example 1 is only that in the preparation method of the polyurethane acrylate photosensitive resin, the second capping agent is not used, and the amount of the first capping agent is 0.1 mol.

[0070] Comparative Example 2

[0071] The difference from Example 1 is only that in the preparation method of the polyurethane acrylate photosensitive resin, the first capping agent is not used, and the amount of the second capping agent is 0.1 mol.

[0072] Comparative Example 3

[0073] The difference from Example 1 is only that in the preparation method of the polyurethane acrylate photosensitive resin, no reactive diluent is added.

[0074] Comparative Example 4

[0075] The difference from Example 1 is only that in the preparation method of the polyurethane acrylate photosensitive resin, the addition amount of the reactive diluent is isooctyl acrylate accounting for 12% of the total mass of the raw materials and isobornyl methacrylate accounting for 2%, so that the viscosity of the obtained polyurethane acrylate photosensitive resin at 25 °C is 45800 cps.

[0076] Comparative Example 5

[0077] The difference from Example 5 is only that in the preparation method of the polyurethane acrylate photosensitive resin, the addition amount of the reactive diluent is 1,6 - hexanediol diacrylate accounting for 45% of the total mass of the raw materials, so that the viscosity of the obtained polyurethane acrylate photosensitive resin at 25 °C is 13600 cps.

[0078] Comparative Example 6

[0079] The difference from Example 1 is only that the small molecule chain extender 1,4 - butanediol is replaced by 1,2,4 - butanetriol.

[0080] Application Example

[0081] To the polyurethane acrylate photosensitive resins prepared in the above - mentioned examples and comparative examples, photoinitiator TPO - L was added respectively, and the addition amount of the photoinitiator was 3% of the total mass of the system, and after stirring evenly, a polyurethane acrylate photosensitive resin composition was obtained.

[0082] After coating the 15-μm polyurethane acrylate photosensitive resin composition on the flexible glass substrate using a film applicator, it was cured in an ultraviolet curing machine, where the radiation conditions of the UV curing machine were a 1000-W mercury lamp, a wavelength of 365 nm, a radiation distance of 15 cm, and a radiation energy of 500 mJ / cm 2 , obtaining a photocured coating.

[0083] The performance of the photocured coating prepared as above was tested, and the test methods were as follows:

[0084] (1) The adhesion test was carried out with reference to the GBT9286-1998 test. The adhesion was tested under normal temperature and humidity conditions and after wiping the surface moisture after boiling in water for 1 h. The adhesion rating was divided into 5 levels, with level 0 indicating the best adhesion.

[0085] (2) The bending test was carried out with reference to the GBT 38001.61-2019 test. The test material was the flexible glass coated with the cured photosensitive resin prepared as above. The test radius was 1.5 mm, the bending amplitude was 180°, and the static bending was carried out at 90 °C. Whether there were scars after bending 200,000 times was checked.

[0086] The test results are shown in Table 1 below.

[0087] Table 1

[0088]

[0089] Commercially available similar products need to be photocured under nitrogen protection, and the performance degradation caused by photocuring in an air environment, such as low surface curing degree and fogging on the surface under high temperature and high humidity environments, increases the energy consumption of product application. At 90 °C high temperature, the resin Tg is too high, resulting in obvious white marks after bending 200,000 times, or the Tg is too low, unable to bond well with the outer coating, resulting in poor wear resistance of the hardened layer. Most commercially available products contain low-boiling-point volatile solvents such as ethyl acetate, methanol, and xylene, and a large amount of VOCs are emitted during later use.

[0090] The product of the present invention adopts a solvent-free system, with 100% active ingredients, and does not produce VOC emissions. It can achieve high-temperature bending resistance performance and has high glass adhesion.

[0091] As can be seen from the above table, the photocured coating prepared from the polyurethane acrylate photosensitive resin of the present invention can have good adhesion and high-temperature bending resistance performance, and there are no creases after bending.

[0092] In Comparative Example 1, due to the non-use of the second capping agent, the adhesion of the product to the screen substrate was poor, and the adhesion test was even worse after boiling in water;

[0093] In Comparative Example 2, since the first capping agent was not used, the product could not form a cross-linked network structure, and both the molecular weight and strength were poor. After boiling water treatment, the adhesion was even worse.

[0094] In Comparative Example 3, since the reactive diluent was not added, the viscosity of the product was too high, making it difficult to wet the surface of the substrate, and it was impossible to coat an ideal material, so the adhesion effect was not good at room temperature.

[0095] In Comparative Example 4, since the amount of the reactive diluent added was relatively small, the viscosity was relatively large, resulting in a relatively poor coating effect. With the increase in the number of folding times, the gloss at the folding position decreased and there were trace creases.

[0096] In Comparative Example 5, since the amount of the reactive diluent added was relatively large, the viscosity was small, resulting in a decrease in the coating thickness during the construction process. At the same time, the increase in the reactive diluent reduced the content of the effective resin components, resulting in a decline in the overall product performance. With the increase in the number of bending times, fractures occurred.

[0097] The applicant declares that the present invention uses the above-mentioned examples to illustrate the polyurethane acrylate photosensitive resin of the present invention, its preparation method and its application in flexible display screens. However, the present invention is not limited to the above-mentioned examples, that is, it does not mean that the present invention must rely on the above-mentioned examples to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent substitution of the raw materials selected for the present invention, the addition of auxiliary components, the selection of specific methods, etc. all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A polyurethane acrylic photosensitive resin, characterized in that: The raw materials for preparing the polyurethane acrylic photosensitive resin include diisocyanate, a macromolecular chain extender, a small molecule chain extender, a first end-capping agent, a second end-capping agent, a catalyst, an inhibitor and an active diluent. The macromolecular chain extender is a polyester polyol, the small molecule chain extender is a small molecule diol, the first end-capping agent is an acrylate containing a hydroxyl group, and the second end-capping agent is an alkoxysilane containing active hydrogen.

2. The polyurethane acrylic photosensitive resin according to claim 1, characterized in that: The diisocyanate is one or a combination of at least two of m-xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate or dicyclohexylmethane diisocyanate.

3. The polyurethane acrylic photosensitive resin according to claim 1, characterized in that: The polyester polyol is a polyester polyol obtained by reacting a diacid or a dianhydride and a diol, wherein the diacid is selected from any one of 1,6-hexanediol and isophthalic acid or a combination of at least two thereof, the dianhydride is selected from phthalic anhydride, and the diol is selected from any one of 1,4-butanediol, diethylene glycol, ethylene glycol, neopentyl glycol or isohexanediol or a combination of at least two thereof; Preferably, the number average molecular weight of the polyester polyol is 1000-1500.

4. The polyurethane acrylic photosensitive resin according to claim 1, characterized in that: The small molecule diol is one or a combination of at least two of ethylene glycol, diethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol or neopentyl glycol; Preferably, the first end-capping agent is one or a combination of at least two of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate or hydroxypropyl methacrylate; Preferably, the second capping agent is 3-aminopropyltrimethoxysilane and / or 3-aminopropyltriethoxysilane.

5. The polyurethane acrylic photosensitive resin according to claim 1, characterized in that: The catalyst is selected from dibutyltin disilicate and / or bismuth laurate; Preferably, the polymerization inhibitor is selected from 2,6-di-tert-butyl-4-methylphenol or p-hydroxyanisole; Preferably, the reactive diluent is selected from any one or a combination of at least two of isooctyl acrylate, isobornyl acrylate, isobornyl methacrylate, methyl methacrylate, butyl acrylate, hexanediol diacrylate, neopentyl glycol diacrylate, dipropylene glycol diacrylate, trimethylolpropane triacrylate or tetrahydrofuran acrylate.

6. The polyurethane acrylic photosensitive resin according to claim 1, characterized in that: The molar ratio of diisocyanate to macromolecular chain extender in the raw material for preparing the polyurethane acrylic photosensitive resin is 1:(0.80-0.85); Preferably, the molar ratio of diisocyanate to small molecule chain extender in the raw material for preparing the polyurethane acrylic photosensitive resin is 1:(0.05-0.08); Preferably, the molar ratio of diisocyanate to the first blocking agent in the raw material for preparing the polyurethane acrylic photosensitive resin is 1:(0.05-0.06); Preferably, the molar ratio of diisocyanate to the second blocking agent in the raw material for preparing the polyurethane acrylic photosensitive resin is 1:(0.05-0.07); Preferably, the amount of the catalyst in the raw material for preparing the polyurethane acrylic photosensitive resin is 0.005%-0.1% of the total mass of the raw material; Preferably, the amount of the polymerization inhibitor in the raw material for preparing the polyurethane acrylic photosensitive resin is 0.1%-0.2% of the total mass of the raw material; Preferably, the amount of the active diluent in the raw material for preparing the polyurethane acrylic photosensitive resin is such that the viscosity of the obtained polyurethane acrylic photosensitive resin at 25° C. reaches 21000-27000 cps.

7. A method for preparing the polyurethane acrylic photosensitive resin according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: (1) mixing diisocyanate, macromolecular chain extender, catalyst and polymerization inhibitor and reacting; (2) adding a small molecule chain extender to the reaction system obtained in step (1) to react; (3) adding the first end-capping agent and the second end-capping agent to the reaction system obtained in step (2), reacting, and then adding a reactive diluent to obtain the polyurethane acrylic photosensitive resin; Preferably, the reaction temperature in step (1) is 50-60° C., and the reaction time is 4-8 h; Preferably, the reaction temperature in step (2) is 70-80°C and the reaction time is 4-8h; Preferably, the reaction temperature in step (3) is 50-60° C., and the reaction time is 1-6 h; Preferably, the reactive diluent is added in step (3) so that the viscosity of the polyurethane acrylic photosensitive resin at 25° C. is 21000-27000 cps.

8. A polyurethane acrylic photosensitive resin composition, characterized in that: The polyurethane acrylic photosensitive resin composition comprises a polyurethane acrylic photosensitive resin and a photoinitiator as described in any one of claims 1 to 6; Preferably, the amount of the photoinitiator added to the polyurethane acrylic photosensitive resin composition is 1-5% of the total weight of the polyurethane acrylic photosensitive resin composition; Preferably, the photoinitiator is selected from any one of TPO-L, TMO, 184, 1173, ITX or DETX, or a combination of at least two thereof.

9. A flexible display light-curing coating, characterized in that: The flexible display screen photocurable coating is obtained by photocuring the polyurethane acrylic photosensitive resin composition according to claim 8.

10. Use of the polyurethane acrylic photosensitive resin according to any one of claims 1 to 6 or the polyurethane acrylic photosensitive resin composition according to claim 8 in silver paste for flexible circuit boards or folding display screens.

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