A low-curing-shrinkage ink composition for encapsulation and its preparation method

Abstract

This invention belongs to the field of organic thin-film encapsulation technology, and relates to an encapsulation ink composition with low curing shrinkage and its preparation method. The encapsulation ink composition, by weight, comprises at least the following raw materials: 30-50 parts of a photocurable aliphatic monomer, 10-40 parts of a photocurable aromatic ether monomer, 15-45 parts of a photocurable phenyl monomer, and 0.01-10 parts of a photoinitiator. The encapsulation ink composition prepared by this invention achieves a very low curing shrinkage rate, and the cured encapsulation ink composition exhibits high transmittance and excellent thermal stability in the wavelength range of 400-800 nm. Furthermore, its excellent flexibility allows for effective encapsulation of organic light-emitting devices, significantly impacting device efficiency and extending device lifespan.

Description

Technical Field

[0001] This invention belongs to the field of organic thin film encapsulation technology, and relates to encapsulation ink compositions, specifically to an encapsulation ink composition with low curing shrinkage and its preparation method, which is a divisional application with application number 2022106257076. Background Technology

[0002] Organic light-emitting diodes (OLEDs) are widely used in emerging fields such as TV panels, tablets, laptops, and smartwatches due to their thinness, low latency, high contrast, and flexibility. However, the organic materials in OLEDs are highly sensitive to moisture and oxygen. Therefore, various methods must be used to effectively encapsulate OLED devices to prevent contact with moisture and oxygen, thereby reducing the aging rate and extending the lifespan of the devices. Thus, research on the encapsulation of organic light-emitting devices is of great significance for improving device efficiency and extending their lifespan.

[0003] Thin-film encapsulation structures involve alternating layers of inorganic and organic films over the organic light-emitting device (OLED) formed within the display area of ​​a substrate, thus covering and protecting the OLED. Thin-film encapsulation effectively prevents moisture and oxygen from entering the device and causing harmful corrosion to the organic molecular materials, thereby providing excellent encapsulation. However, most publicly available organic films used for encapsulation in optoelectronic devices are UV-curable inks, classified as free radical or cationic based on their curing reaction. Currently, over 95% are acrylate free radical type, characterized by a generally large volume shrinkage rate during curing. The stress and volume defects generated by this shrinkage during curing are more difficult to eliminate, thus requiring thin-film encapsulation structures to have a higher requirement for reducing shrinkage. Excessive volume shrinkage can easily cause the inorganic film to rupture, leading to the failure of the thin-film encapsulation structure. Furthermore, during prolonged exposure to high temperatures, the organic layer of the thin-film encapsulation may peel off from the inorganic layer, affecting the protection of the OLED's organic materials.

[0004] Chinese patent application CN107075033A, published on August 18, 2017, discloses a composition for a display sealing material. The sealing material prepared using this composition exhibits high plasma resistance, low moisture permeability, low oxygen permeability, and low surface roughness, enabling the formation of a highly smooth organic protective layer. However, the sealing material prepared using this composition has a large curing shrinkage rate. After curing, stress is easily generated in the adjacent inorganic material layer within the flexible thin-film encapsulation structure, leading to cracking of the inorganic thin-film layer and ultimately causing the failure of the thin-film encapsulation structure. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide an ink composition for encapsulation with low curing shrinkage and its preparation method. This composition can achieve a balance in terms of curing rate, curing shrinkage, light transmittance, thermal stability and other aspects in the wavelength range of 400-800 nm, thereby effectively achieving excellent encapsulation function.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] On the one hand, the present invention provides an ink composition for encapsulation with low curing shrinkage, comprising at least the following raw materials by weight: 20-60 parts of photocurable aliphatic monomer, 5-50 parts of photocurable aromatic ether monomer, 10-55 parts of photocurable phenyl monomer, and 0.01-10 parts of photoinitiator.

[0008] Preferably, the ink composition for encapsulation comprises, by weight, at least the following raw materials: 30-50 parts of photocurable aliphatic monomer, 10-40 parts of photocurable aromatic ether monomer, 15-45 parts of photocurable phenyl monomer, and 0.01-10 parts of photoinitiator.

[0009] Furthermore, the photocurable aliphatic monomer is a non-aromatic monomer that does not contain aromatic groups and may include non-silicon-based (meth)acrylates containing substituted or unsubstituted long-chain alkylene groups.

[0010] Specifically, the photocurable aliphatic monomer is a (meth)acrylate with C1 to C20 alkylene groups.

[0011] Preferably, the photocurable aliphatic monomer is one or more of the following: ethyl methacrylate, propyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, nonyl methacrylate, decyl methacrylate, undecyl methacrylate, dodecyl methacrylate, tridecyl methacrylate, tetradecyl methacrylate, pentadecyl methacrylate, ethylene glycol dimethacrylate, propylene glycol dimethacrylate, pentyl glycol dimethacrylate, hexyl glycol dimethacrylate, heptyl glycol dimethacrylate, octyl glycol dimethacrylate, nonyl glycol dimethacrylate, decyl glycol dimethacrylate, undecyl glycol dimethacrylate, dodecyl glycol dimethacrylate, tridecyl glycol dimethacrylate, tetradecyl glycol dimethacrylate, and pentadecyl glycol dimethacrylate.

[0012] Preferably, the photocurable aliphatic monomer is a C10-C15 alkylene di(meth)acrylate, which can effectively reduce the glass transition temperature of the encapsulation ink composition for UV inkjet printing and improve the plasticizing effect, thereby giving the cured encapsulation ink composition good flexibility.

[0013] More preferably, the photocurable aliphatic monomer is one or more of the following: decyl di(meth)acrylate, undecyl di(meth)acrylate, dodecyl di(meth)acrylate, tridecyl di(meth)acrylate, tetradecyl di(meth)acrylate, and pentadecyl di(meth)acrylate.

[0014] It is important to emphasize that when the photocurable aliphatic monomer has a bifunctionality, the photocuring rate of the encapsulation ink composition can be increased. At the same time, the photocured encapsulation ink composition has a highly cross-linked network structure, which effectively balances the flexibility and thermal stability of the cured encapsulation ink composition.

[0015] Furthermore, the structural formula of the photocurable aromatic ether monomer is as follows: Formula I:

[0016]

[0017] Wherein, R3 and R4 may be the same or different, and each of R3 and R4 is independently one of hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted cycloalkyl, and substituted or unsubstituted heteroalkyl; preferably, R3 and R4 may be the same or different, and each of R3 and R4 is independently one of hydrogen, substituted or unsubstituted C1 to C12 alkyl, substituted or unsubstituted C1 to C12 alkoxy, substituted or unsubstituted C6 to C30 aryl, substituted or unsubstituted C6 to C30 heteroaryl, substituted or unsubstituted C3 to C30 cycloalkyl, and substituted or unsubstituted C3 to C30 heteroalkyl;

[0018] X1 and X2 may be the same or different, and X1 and X2 are each independently any one of a single bond, a substituted or unsubstituted straight-chain C1 to C12 alkylene group, or a substituted or unsubstituted C1 to C12 alkoxy group;

[0019] Y1 and Y2 are each independently represented by structure II, and a and b are integers from 0 to 2, and a and b are not both 0 at the same time;

[0020]

[0021] Wherein, * indicates the linking site with carbon atoms on X1 and X2; R5 is hydrogen or C1 to C5 alkyl, preferably, R5 is hydrogen or methyl.

[0022] Furthermore, the photocurable aromatic ether monomer includes at least one of formulas (1) to (8):

[0023]

[0024] Furthermore, the weight ratio of the photocurable aliphatic monomer to the photocurable aromatic ether monomer is (35-45):(20-30).

[0025] On the one hand, the present invention can effectively balance the flexibility and thermal stability of the cured encapsulation ink composition by adding photocurable aliphatic monomers. However, this results in a large curing shrinkage rate of the encapsulation ink composition, which affects the encapsulation effect on OLEDs. On this basis, the present invention can effectively reduce the curing shrinkage rate of the encapsulation ink composition by introducing photocurable aromatic ether monomers into the system of the encapsulation ink composition. At the same time, it can also improve the excellent light transmittance of the cured encapsulation ink composition in the wavelength range of 400-800nm.

[0026] On the other hand, when the weight ratio of photocurable aliphatic monomers to photocurable aromatic ether monomers is too small, the curing encapsulation ink composition has poor flexibility, which is insufficient to meet the flexibility requirements of OLED encapsulation materials. Conversely, when the weight ratio of photocurable aliphatic monomers to photocurable aromatic ether monomers is too large, the curing shrinkage rate of the curing encapsulation ink composition is large. Therefore, this invention limits the weight ratio of photocurable aliphatic monomers to photocurable aromatic ether monomers to (35-45):(20-30). When the weight ratio is this, the curing shrinkage rate of the encapsulation ink composition can be effectively reduced (4.03%), and the transmittance in the wavelength range of 400-800 nm can reach as high as 97.23%. This is because: on the one hand, the flexible groups (-O-) between the benzene rings, this unique molecular structure allows the two benzene rings to rotate, thus enabling good compatibility with larger photocurable aliphatic monomers; on the other hand, when photocurable aromatic ether monomers and photocurable aliphatic monomers work synergistically, they achieve better π-π stacking, thereby effectively reducing the curing shrinkage rate of the encapsulation ink composition while also enabling the cured encapsulation ink composition to have excellent light transmittance in the wavelength range of 400–800 nm.

[0027] Furthermore, the structural formula of the photocurable phenyl monomer is as follows: Formula III:

[0028]

[0029] Among them, R6, R7, R8, R9, R 10 R 11 Whether they are the same or different, R6, R7, R8, R9, R 10 R 11 Each of the following is independently hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted hydroxyalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkoxy, substituted or unsubstituted phenolic hydroxyl, or any one of structural formula IV;

[0030] Preferred values ​​are R6, R7, R8, R9, and R. 10 R 11 Whether they are the same or different, R6, R7, R8, R9, R 10 R 11 Each of the following is independently hydrogen, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C1 to C50 cycloalkyl group, a substituted or unsubstituted C1 to C10 hydroxyalkyl group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C6 to C30 heteroaryl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted C6 to C30 alkoxy group, a substituted or unsubstituted C6 to C30 phenolic hydroxyl group, or any one of the following structural formulas:

[0031] Preferably, R6, R7, R8, R9, R 10 R 11 At least one is structural form IV:

[0032]

[0033] Where * represents the linking site of the aromatic carbon in the compound of structural formula IV, and n2 and n3 are integers from 0 to 20; R 12 It can be hydrogen or methyl.

[0034] More preferably, n2 and n3 are integers from 0 to 10, and n2 is not 0.

[0035] Preferably, the photocurable phenyl monomer is polyethylene glycol o-phenyl ether acrylate, 2-phenoxyethyl acrylate, 2-([1,1':4',1"-terphenyl]-2'-oxy)acrylic acid, 2-(p-tolyloxy)ethyl acrylate, 2-(m-tolyloxy)ethyl acrylate, 2-(3-methoxyphenoxy)ethyl acrylate, 2-phenoxyethyl acrylic acid, 2-phenoxyethyl (meth)acrylic acid, 3-phenoxypropyl acrylic acid, 3-phenoxypropyl (meth)acrylic acid, 4-phenoxybutyl acrylic acid, 4-phenoxybutyl (meth)acrylic acid, 5-phenoxypentyl acrylic acid, 5-phenoxypentyl (meth)acrylic acid, 6-phenoxyhexyl acrylic acid, 6-phenoxy... 7-Phenoxyheptylacrylic acid, 7-Phenoxyheptylacrylic acid, 8-Phenoxyoctylacrylic acid, 8-Phenoxyoctylacrylic acid, 9-Phenoxynonylacrylic acid, 9-Phenoxynonylacrylic acid, 10-Phenoxydecylacrylic acid, 10-Phenoxydecylacrylic acid, 2-([1,1'-biphenyl]-4-yloxy)ethyl acrylate, 2-([1,1'-biphenyl]-4-yloxy)ethyl (meth)acrylate, 3-([1,1'-biphenyl]-4-yloxy)propyl acrylate, 3-([1,1'-biphenyl]-4-yloxy)propyl (meth)acrylate, 4-([1,1'-Biphenyl]-4-yloxy)butyl acrylate, 4-phenylbutyl(meth)acrylate, 2-(2-methylphenyl)ethyl(meth)acrylate, 2-(3-methylphenyl)ethyl(meth)acrylate, 2-(4-methylphenyl)ethyl(meth)acrylate, 2-(4-propylphenyl)ethyl(meth)acrylate, 2-(4-(1-methylethyl)phenyl)ethyl(meth)acrylate, 2-(4-methoxyphenyl)ethyl(meth)acrylate Acrylates, 2-(4-cyclohexylphenyl)ethyl(meth)acrylates, 2-(2-chlorophenyl)ethyl(meth)acrylates, 2-(3-chlorophenyl)ethyl(meth)acrylates, 2-(4-chlorophenyl)ethyl(meth)acrylates, 2-(4-bromophenyl)ethyl(meth)acrylates, 2-(3-phenylphenyl)ethyl(meth)acrylates, 4-(diphenyl-2-yloxy)butyl(meth)acrylates, 3-(diphenyl-2-yloxy)butyl(meth)acrylates 2-(diphenyl-2-yloxy)butyl (meth)acrylate, 1-(diphenyl-2-yloxy)butyl (meth)acrylate, 4-(diphenyl-2-yloxy)propyl (meth)acrylate, 3-(diphenyl-2-yloxy)propyl (meth)acrylate, 2-(diphenyl-2-yloxy)propyl (meth)acrylate, 1-(diphenyl-2-yloxy)propyl (meth)acrylate The ester, 4-(diphenyl-2-yloxy)ethyl(meth)acrylate, 3-(diphenyl-2-yloxy)ethyl(meth)acrylate, 2-(diphenyl-2-yloxy)ethyl(meth)acrylate, 1-(diphenyl-2-yloxy)ethyl(meth)acrylate, 2-(2-(2-([1,1'-biphenyl]-2-oxo)ethoxy)ethoxy)propylene, and any one of 2-([1,1'-biphenyl]-2-yl)acrylic acid.

[0036] Furthermore, the relative molecular mass of the photocurable phenyl monomer is 100–1000 g / mol;

[0037] Preferably, the relative molecular mass of the photocurable phenyl monomer is 150–500 g / mol.

[0038] More preferably, the photocurable phenyl monomer is 2-phenoxyethyl acrylate, 2-phenoxyethyl (meth) acrylate, 3-phenoxypropyl acrylate, 4-phenoxybutyl acrylate, 2-([1,1'-biphenyl]-4-yloxy)ethyl acrylate, 2-([1,1'-biphenyl]-4-yloxy)ethyl (meth) acrylate, 3-([1,1'-biphenyl]-4-yloxy)propyl acrylate, 3-([1,1'-biphenyl]-4-yloxy)propyl (meth) acrylate, 4-(diphenyl) The following are all of the following: 2-(2-yloxy)butyl(meth)acrylate, polyethylene glycol o-phenyl phenyl ether acrylate, 2-phenoxyethyl acrylate, 2-(2-(2-([1,1'-biphenyl]-2-oxo)ethoxy)ethoxy)propylene, 2-([1,1'-biphenyl]-2-yl)acrylic acid, 2-([1,1':4',1"-terphenyl]-2'-oxo)acrylic acid, 2-(p-tolyloxy)ethyl acrylate, 2-(m-tolyloxy)ethyl acrylate, and 2-(3-methoxyphenoxy)ethyl acrylate.

[0039] Furthermore, the weight ratio of the photocurable aromatic ether monomer to the photocurable phenyl monomer is (15-35):(20-40).

[0040] In this invention, the curing shrinkage rate of the encapsulation ink composition is unsatisfactory because the weight ratio of photocurable phenyl monomers with a relative molecular mass of 150–500 g / mol is either too high or too low. Therefore, this invention limits the weight ratio of photocurable aromatic ether monomers to photocurable phenyl monomers with a relative molecular mass of 150–500 g / mol to (15–35):(20–40), which effectively reduces the curing shrinkage rate of the encapsulation ink composition and simultaneously improves the thermal stability of the cured encapsulation ink composition. This is because: when the molecular weight of the photocurable phenyl monomer is 150-500 g / mol, it can exist uniformly in the system, and its own ethoxy (-CH2-CH2-O-) structure makes the free volume of the encapsulation ink composition small; in addition, the phenyl structure of the photocurable phenyl monomer and the phenyl structure of the photocurable aromatic ether monomer with flexible group (-O-) can be arranged in parallel with each other, and there is a non-bonded interaction between adjacent phenyl groups. This interaction causes the phenyl groups to be in a stacked state, which reduces the free volume of the encapsulation ink composition and also greatly affects the conformation of the chain segments of the encapsulation ink composition. Therefore, while effectively reducing the curing shrinkage rate of the encapsulation ink composition, it also improves the thermal stability of the cured encapsulation ink composition.

[0041] Furthermore, the photoinitiator is one or more of the following: benzoin and its derivatives, benzoyl ketal derivatives, dialkoxyacetophenone, alkyl phenyl ketone, acyl phosphorus oxide, esterified oxime ketone compound, aryl peroxide ester compound, halomethyl aromatic ketone, organic sulfur-containing compound, and benzoyl carboxylate.

[0042] Preferably, the photoinitiator is an acylphosphine oxide, specifically diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide (CAS: 75980-60-8).

[0043] On the other hand, the present invention also provides a method for preparing an ink composition for encapsulation with low curing shrinkage as described in part or all of the above, specifically as follows: under light-proof conditions, a photocurable aliphatic monomer, a photocurable aromatic ether monomer, a photocurable phenyl monomer, and a photoinitiator are added to a brown light-proof bottle and mixed for 30 to 80 minutes until homogeneous, thereby obtaining an ink composition for encapsulation with low curing shrinkage.

[0044] Furthermore, the present invention also provides an OLED encapsulation structure, comprising, from top to bottom, an inorganic layer, an organic layer, another inorganic layer, an OLED device, and a substrate. In the direction of the substrate, the encapsulation structure includes inorganic and organic layers alternately stacked on the OLED device and the substrate.

[0045] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0046] (1) By limiting the photocurable aliphatic monomer to di(meth)acrylate with C10 to C15 alkylene groups, the present invention can effectively reduce the glass transition temperature of the encapsulation ink composition for UV inkjet printing and improve the plasticizing effect, thereby giving the cured encapsulation ink composition good flexibility.

[0047] (2) By limiting the weight ratio of photocurable aliphatic monomers to photocurable aromatic ether monomers to (35-45): (20-30), the present invention can effectively reduce the curing shrinkage rate (4.03%) of the ink composition for encapsulation, and the transmittance in the wavelength range of 400-800 nm can be as high as 97.23%.

[0048] (3) By limiting the weight ratio of photocurable aromatic ether monomers to photocurable phenyl monomers with a relative molecular mass of 150-500 g / mol to (15-35): (20-40), the present invention can effectively reduce the curing shrinkage rate of the ink composition for packaging and improve the thermal stability of the cured ink composition for packaging.

[0049] (4) The encapsulation ink composition provided by this invention has suitable viscosity and surface tension, can be coated using inkjet printing, and exhibits very low curing shrinkage. Furthermore, the cured encapsulation ink composition has high transmittance and excellent thermal stability in the wavelength range of 400–800 nm. In addition, its excellent flexibility allows for effective encapsulation of organic light-emitting devices, significantly improving device efficiency and extending device lifespan. Attached Figure Description

[0050] The accompanying drawings are incorporated in and form part of this specification, and together with the description serve to explain the principles of the invention.

[0051] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0052] Figure 1 This is a cross-sectional view of the OLED thin-film encapsulation structure provided by the present invention.

[0053] Among them: 1. Substrate; 2. Inorganic layer; 3. OLED device; 4. Organic layer. Detailed Implementation

[0054] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of compositions and methods consistent with some aspects of the invention as detailed in the appended claims.

[0055] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0056] Example 1

[0057] This embodiment provides an ink composition for packaging with low curing shrinkage, comprising the following raw materials by weight: 40 parts of photocurable aliphatic monomer, 30 parts of photocurable aromatic ether monomer, 30 parts of photocurable phenyl monomer, and 2 parts of photoinitiator.

[0058] Specifically:

[0059] The photocurable aliphatic monomer is dodecyl di(meth)acrylate;

[0060] The photocurable aromatic ether monomer is of formula (3).

[0061] The photocurable phenyl monomer is polyethylene glycol o-phenyl phenyl ether acrylate (CAS No.: 72009-86-0; Sigma-Aldrich);

[0062] The photoinitiator is diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide.

[0063] Among them, photocurable aromatic ether monomers The synthetic route is as follows:

[0064]

[0065] The specific preparation process is as follows: 1 mol of 4-bromoanisole, 1.5 mol of 3-hydroxybenzyl alcohol, 0.01 mol of CuI, 0.01 mol of BPPO (CAS: 21022-17-3), and 2 mol of K3PO4 were placed in a reaction flask, and then 300 mL of DMF was added. The gas was replaced with argon (sealed), and the reaction was carried out at 100 °C for 12 h. A small amount of the reaction solution was taken for TLC monitoring. After the 4-bromoanisole was completely consumed, the reaction was stopped. After cooling to room temperature, ethyl acetate was added for dilution, and the mixture was washed twice with water and once with brine. After removing the solvent by vacuum distillation, the intermediate 3-A was obtained by column chromatography with a yield of 82%.

[0066] 1 mol of intermediate 3-A, 1.1 mol of acrylic acid, 0.01 mol of concentrated sulfuric acid, 0.05 mol of hydroquinone, and 100 mL of toluene were added to a reaction flask. The mixture was refluxed at 110 °C to remove water. TLC monitoring was performed until the intermediate was completely consumed. After cooling to room temperature, 200 mL of diethyl ether was added to dilute the reaction solution. The mixture was washed once with 0.2 N NaOH solution and once with water. The organic phase was dried over anhydrous magnesium sulfate. After removing the solvent by vacuum distillation, the target product was obtained by column chromatography with a yield of 86%.

[0067] Based on this encapsulation ink composition, this embodiment also provides a method for preparing an encapsulation ink composition with low curing shrinkage, specifically including: under light-protected conditions, adding a photocurable aliphatic monomer, a photocurable aromatic ether monomer, a photocurable phenyl monomer, and a photoinitiator to a brown light-protected bottle, mixing for 60 minutes until homogeneous, thereby obtaining an encapsulation ink composition (I) with low curing shrinkage.

[0068] Example 2

[0069] This embodiment provides an ink composition for packaging with low curing shrinkage. By weight, the raw materials include: 40 parts of photocurable aliphatic monomer, 30 parts of photocurable aromatic ether monomer, 30 parts of photocurable phenyl monomer, and 2 parts of photoinitiator.

[0070] Specifically:

[0071] The photocurable aliphatic monomer is dodecyl di(meth)acrylate;

[0072] The photocurable aromatic ether monomer is of formula (2).

[0073] The photocurable phenyl monomer is: 2-(2-(2-([1,1'-biphenyl]-2-oxo)ethoxy)ethoxy)ethyl acrylate;

[0074] The photoinitiator is diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide.

[0075] Among them, photocurable aromatic ether monomers The synthetic route is as follows:

[0076]

[0077] The specific preparation process is as follows: 1 mol of 4-tert-butylbromobenzene, 1.5 mol of 3-hydroxybenzyl alcohol, 0.01 mol of CuI, 0.01 mol of BPPO (CAS: 21022-17-3), and 2 mol of K3PO4 were placed in a reaction flask, and then 300 mL of DMF was added. The gas was replaced with argon (sealed), and the reaction was carried out at 100 °C for 12 h. A small amount of the reaction solution was taken for TLC monitoring. After the 4-tert-butylbromobenzene was completely consumed, the reaction was stopped. After cooling to room temperature, ethyl acetate was added for dilution, and the mixture was washed twice with water and once with brine. After removing the solvent by vacuum distillation, the intermediate 5-A was obtained by column chromatography with a yield of 85%.

[0078] 1 mol of intermediate 5-A, 1.1 mol of acrylic acid, 0.01 mol of concentrated sulfuric acid, 0.05 mol of hydroquinone, and 100 mL of toluene were added to a reaction flask. The mixture was refluxed at 110 °C to remove water. TLC monitoring was performed until the intermediate was completely consumed. After cooling to room temperature, 200 mL of diethyl ether was added to dilute the reaction solution. The mixture was washed once with 0.2 N NaOH solution and once with water. The organic phase was dried over anhydrous magnesium sulfate. After removing the solvent by vacuum distillation, the target product was obtained by column chromatography with a yield of 91%.

[0079] The preparation process of ethyl 2-(2-(2-([1,1'-biphenyl]-2-oxo)ethoxy)ethoxy)acrylate is as follows:

[0080] 1 mol of o-phenylphenol, 1 mol of NaH, and 1 mol of 2-chloroethoxy-2-ethoxydiethanol were added to a reaction flask, followed by 200 mL of anhydrous DMF. The reaction was carried out at 120 °C, and the reaction was monitored by TLC until the o-phenylphenol reaction was complete. After cooling to room temperature, the system was filtered through diatomaceous earth. The filtrate was purified by vacuum distillation to remove the solvent, and then separated by column chromatography to obtain intermediate 12-A with a yield of 84%.

[0081] 1 mol of intermediate 12-A, 1.1 mol of acrylic acid, 100 mL of toluene, 0.01 mol of concentrated sulfuric acid, and 0.05 mol of hydroquinone were added to a reaction flask. The mixture was refluxed at 110 °C to remove water. TLC monitoring was performed until the intermediate was completely consumed. After cooling to room temperature, 200 mL of diethyl ether was added to dilute the reaction solution. The mixture was washed once with 0.2 NNaOH solution and once with water. The organic phase was dried over anhydrous magnesium sulfate. After removing the solvent by vacuum distillation, the target product was obtained by column chromatography with a yield of 81%.

[0082] Based on this encapsulation ink composition, this embodiment also provides a method for preparing an encapsulation ink composition with low curing shrinkage, specifically including: under light-protected conditions, adding a photocurable aliphatic monomer, a photocurable aromatic ether monomer, a photocurable phenyl monomer, and a photoinitiator to a brown light-protected bottle, mixing for 60 minutes until homogeneous, thereby obtaining an encapsulation ink composition (II) with low curing shrinkage.

[0083] Example 3

[0084] This embodiment provides an ink composition for packaging with low curing shrinkage, comprising the following raw materials by weight: 40 parts of photocurable aliphatic monomer, 30 parts of photocurable aromatic ether monomer, 30 parts of photocurable phenyl monomer, and 2 parts of photoinitiator.

[0085] Specifically:

[0086] The photocurable aliphatic monomer is dodecyl di(meth)acrylate;

[0087] The photocurable aromatic ether monomer is of formula (4). (Sigma-Aldrich);

[0088] The photocurable phenyl monomer is polyethylene glycol o-phenyl phenyl ether acrylate (CAS No.: 72009-86-0; Sigma-Aldrich);

[0089] The photoinitiator is diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide.

[0090] Based on this encapsulation ink composition, this embodiment also provides a method for preparing an encapsulation ink composition with low curing shrinkage, specifically including: under light-protected conditions, adding a photocurable aliphatic monomer, a photocurable aromatic ether monomer, a photocurable phenyl monomer, and a photoinitiator to a brown light-protected bottle, mixing for 65 minutes until homogeneous, thereby obtaining an encapsulation ink composition (III) with low curing shrinkage.

[0091] Example 4

[0092] This embodiment provides an ink composition for packaging with low curing shrinkage, comprising the following raw materials by weight: 40 parts of photocurable aliphatic monomer, 30 parts of photocurable aromatic ether monomer, 30 parts of photocurable phenyl monomer, and 2 parts of photoinitiator.

[0093] The photocurable aliphatic monomer is dodecyl di(meth)acrylate;

[0094] The photocurable aromatic ether monomer is of formula (4). (Sigma-Aldrich);

[0095] The photocurable phenyl monomer is ethyl 2-(2-(2-([1,1'-biphenyl]-2-oxo)ethoxy)ethoxy)acrylate, and its preparation process is the same as that of ethyl 2-(2-(2-([1,1'-biphenyl]-2-oxo)ethoxy)ethoxy)acrylate in Example 2;

[0096] The photoinitiator is diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide.

[0097] Based on this encapsulation ink composition, this embodiment also provides a method for preparing an encapsulation ink composition with low curing shrinkage, specifically including: under light-protected conditions, adding a photocurable aliphatic monomer, a photocurable aromatic ether monomer, a photocurable phenyl monomer, and a photoinitiator to a brown light-protected bottle, mixing for 58 minutes until homogeneous, thereby obtaining an encapsulation ink composition (IV) with low curing shrinkage.

[0098] Example 5

[0099] This embodiment provides an ink composition for packaging with low curing shrinkage, comprising the following raw materials by weight: 40 parts of photocurable aliphatic monomer, 30 parts of photocurable aromatic ether monomer, 30 parts of photocurable phenyl monomer, and 2 parts of photoinitiator.

[0100] The photocurable aliphatic monomer is dodecyl di(meth)acrylate;

[0101] The photocurable aromatic ether monomer is of formula (3).

[0102] The photocurable phenyl monomer is ethyl 2-([1,1'-biphenyl]-2-yl)acrylate (Sigma-Aldrich);

[0103] The photoinitiator is diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide.

[0104] Based on this encapsulation ink composition, this embodiment also provides a method for preparing an encapsulation ink composition with low curing shrinkage, specifically including: under light-protected conditions, adding a photocurable aliphatic monomer, a photocurable aromatic ether monomer, a photocurable phenyl monomer, and a photoinitiator to a brown light-protected bottle, mixing for 50 minutes until homogeneous, thereby obtaining an encapsulation ink composition (V) with low curing shrinkage.

[0105] Example 6

[0106] This embodiment provides an ink composition for packaging with low curing shrinkage, comprising the following raw materials by weight: 40 parts of photocurable aliphatic monomer, 30 parts of photocurable aromatic ether monomer, 30 parts of photocurable phenyl monomer, and 2 parts of photoinitiator.

[0107] The photocurable aliphatic monomer is dodecyl di(meth)acrylate;

[0108] The photocurable aromatic ether monomer is a mixture of the structures shown in formula (3) and formula (4) with a weight ratio of 1:1 (Sigma-Aldrich);

[0109] The photocurable phenyl monomer is 2-phenoxyethyl acrylate (Sigma-Aldrich);

[0110] The photoinitiator is diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide.

[0111] Based on this encapsulation ink composition, this embodiment also provides a method for preparing an encapsulation ink composition with low curing shrinkage, specifically including: under light-protected conditions, adding a photocurable aliphatic monomer, a photocurable aromatic ether monomer, a photocurable phenyl monomer, and a photoinitiator to a brown light-protected bottle, mixing for 68 minutes until homogeneous, thereby obtaining an encapsulation ink composition (VI) with low curing shrinkage.

[0112] Example 7

[0113] This embodiment provides an ink composition for encapsulation with low curing shrinkage, comprising the following raw materials by weight: 20 parts of photocurable aliphatic monomer, 5 parts of photocurable aromatic ether monomer, 10 parts of photocurable phenyl monomer, and 0.7 parts of photoinitiator.

[0114] Specifically:

[0115] The photocurable aliphatic monomer is dodecyl di(meth)acrylate;

[0116] The photocurable aromatic ether monomer is of formula (4). (Sigma-Aldrich);

[0117] The photocurable phenyl monomer is polyethylene glycol o-phenyl phenyl ether acrylate (CAS No.: 72009-86-0; Sigma-Aldrich);

[0118] The photoinitiator is diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide.

[0119] Based on this encapsulation ink composition, this embodiment also provides a method for preparing an encapsulation ink composition with low curing shrinkage, specifically including: under light-protected conditions, adding a photocurable aliphatic monomer, a photocurable aromatic ether monomer, a photocurable phenyl monomer, and a photoinitiator to a brown light-protected bottle, mixing for 30 minutes until homogeneous, thereby obtaining an encapsulation ink composition (VII) with low curing shrinkage.

[0120] Example 8

[0121] This embodiment provides an ink composition for encapsulation with low curing shrinkage, comprising the following raw materials by weight: 60 parts of photocurable aliphatic monomer, 50 parts of photocurable aromatic ether monomer, 55 parts of photocurable phenyl monomer, and 1.65 parts of photoinitiator.

[0122] Specifically:

[0123] The photocurable aliphatic monomer is dodecyl di(meth)acrylate;

[0124] The photocurable aromatic ether monomer is of formula (4). (Sigma-Aldrich);

[0125] The photocurable phenyl monomer is polyethylene glycol o-phenyl phenyl ether acrylate (CAS No.: 72009-86-0; Sigma-Aldrich);

[0126] The photoinitiator is diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide.

[0127] Based on this encapsulation ink composition, this embodiment also provides a method for preparing an encapsulation ink composition with low curing shrinkage, specifically including: under light-protected conditions, adding a photocurable aliphatic monomer, a photocurable aromatic ether monomer, a photocurable phenyl monomer, and a photoinitiator to a brown light-protected bottle, mixing for 80 minutes until homogeneous, thereby obtaining an encapsulation ink composition (VIII) with low curing shrinkage.

[0128] Comparative Example 1

[0129] The specific implementation method of Comparative Example 1 is the same as that of Example 3; the difference from Example 3 is that no photocurable aliphatic monomers were added in Comparative Example 1.

[0130] Comparative Example 2

[0131] The specific implementation method of Comparative Example 2 is the same as that of Example 3; the difference from Example 3 is that no photocurable aromatic ether monomers are added in Comparative Example 2.

[0132] Comparative Example 3

[0133] The specific implementation method of Comparative Example 3 is the same as that of Example 3; the difference from Example 3 is that no photocurable phenyl monomer was added in Comparative Example 3.

[0134] Comparative Example 4

[0135] The specific implementation method of Comparative Example 4 is the same as that of Example 3; the difference from Example 3 is that the amount of photocurable aromatic ether monomer added in Comparative Example 4 is 80 parts.

[0136] Comparative Example 5

[0137] The specific implementation method of Comparative Example 5 is the same as that of Example 3; the difference from Example 3 is that the amount of photocurable aromatic ether monomer added in Comparative Example 5 is 3 parts.

[0138] The compositions obtained in Examples 1-8 and Comparative Examples 1-5 were subjected to performance tests, specifically including the following aspects:

[0139] (1) Curing shrinkage rate: The encapsulation ink composition was inkjet printed onto a glass substrate and the shrinkage rate was 30 mW / cm. 2 The sample was then subjected to UV curing for 120 seconds by UV irradiation to produce a sample with dimensions of 5mm × 3cm × 1mm (width × length × thickness).

[0140] Curing shrinkage rate η = (Vb - Va) / Vb × 100%;

[0141] Where Vb is the volume before curing and Va is the volume after curing.

[0142] (2) Photocurability: The encapsulation ink composition was inkjet printed onto a glass substrate and the curability was 30 mW / cm². 2 A sample with dimensions of 3 cm × 7.5 cm × 18 μm (width × length × thickness) was prepared by UV curing for 120 s under UV irradiation. Then, FT-IR (Nicolet iS50, Thermo-Fisher) was used to measure the ink before curing and the organic film after curing at 1635 cm⁻¹. -1 (C=C) and 1720cm -1 The intensity of the absorption peak near (C=O).

[0143] UV curing rate (%) = |1 - (F / S)| × 100;

[0144] Where F represents the cured organic film at 1635 cm⁻¹ -1 The absorption peak intensity near 1720 cm⁻¹ is similar to that at 1720 cm⁻¹. -1 The ratio of the intensity of the absorption peaks near the target; S represents the intensity of the uncured ink at 1635 cm⁻¹. -1 The absorption peak intensity near 1720 cm⁻¹ is similar to that at 1720 cm⁻¹. -1 The ratio of the intensity of the nearby absorption peaks.

[0145] (3) Light transmittance: The ink composition for encapsulation is inkjet printed onto the glass substrate and the transmittance is 30 mW / cm. 2 The sample was cured by UV irradiation for 120 seconds to produce a sample with dimensions of 3cm × 7.5cm × 18μm (width × length × thickness). The transmittance of the cured film in the visible light range of 400nm to 700nm was then measured by UV spectrophotometer (Fluoromax-4, HORIBA Jobin Yvon, France).

[0146] (4) Thermal stability: The encapsulation ink composition is inkjet printed onto a glass substrate and the thermal stability is within 30mW / cm². 2 The sample was cured by UV irradiation for 120 seconds to produce a sample with a thickness of 10 μm. According to GB / T 1735-2009 <Determination of Heat Resistance of Coating Film>, the cured UV inkjet printing encapsulation ink composition was heated to 100℃ in a blower oven and held for 2 hours, and then cooled to 25℃. The sample was then compared with a pre-preserved standard plate to check for discoloration, peeling, wrinkling and other conditions.

[0147] The performance test results of the compositions in each embodiment and comparative example are shown in Table 1 below:

[0148] Table 1

[0149] Curing shrinkage rate (%) UV curing rate (%) Light transmittance (%) thermal stability Example 1 4.16 96.80 96.88 good Example 2 4.25 97.12 96.86 good Example 3 4.03 97.32 97.23 good Example 4 4.13 96.91 96.68 good Example 5 4.16 96.92 97.01 good Example 6 4.20 96.93 97.15 good Example 7 4.46 96.82 96.55 good Example 8 4.51 96.86 96.43 good Comparative Example 1 6.02 94.26 93.21 Wrinkling, peeling Comparative Example 2 6.26 93.23 94.12 Wrinkling, peeling Comparative Example 3 6.03 92.86 93.23 Wrinkling, peeling Comparative Example 4 6.03 94.53 94.67 Wrinkling, peeling Comparative Example 5 6.01 94.23 94.62 Wrinkling, peeling

[0150] As can be seen from the data in Table 1, the low curing shrinkage ink composition for encapsulation provided by the present invention has a very low curing shrinkage rate, and the lowest curing shrinkage rate can be reduced to 4.03%. In addition, the cured encapsulation ink composition has high light transmittance in the wavelength range of 400-800nm, with a light transmittance as high as 97.23%, and excellent photocuring rate and thermal stability.

[0151] Conversely, Comparative Example 1 (without photocurable aliphatic monomers), Comparative Example 2 (without photocurable aromatic ether monomers), Comparative Example 3 (without photocurable phenyl monomers), Comparative Example 4 (although containing photocurable aliphatic monomers, photocurable aromatic ether monomers, and photocurable phenyl monomers, the amount of photocurable aromatic ether monomers added is 80 parts, exceeding its maximum addition amount of 50 parts), and Comparative Example 5 (although containing photocurable aliphatic monomers, photocurable aromatic ether monomers, and photocurable phenyl monomers, the amount of photocurable aromatic ether monomers added is 3 parts, less than its minimum addition amount of 5 parts), all failed to achieve the very low curing shrinkage rate effect of this invention, and could not meet the packaging requirements of high light transmittance and excellent thermal stability for OLED devices.

[0152] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention.

[0153] It should be understood that the present invention is not limited to the content already described above, and various modifications and changes can be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A packaging ink composition with low curing shrinkage, characterized in that, By weight, it shall include at least the following ingredients: 30-50 parts of photocurable aliphatic monomers, 10-40 parts of photocurable aromatic ether monomers, 15-45 parts of photocurable phenyl monomers, and 0.01-10 parts of photoinitiator; The photocurable aromatic ether monomer and the photocurable phenyl monomer are in a weight ratio of (15~35):(20~40), the photocurable aliphatic monomer and the photocurable aromatic ether monomer are in a weight ratio of (35~45):(20~30), the photocurable phenyl monomer has a relative molecular mass of 150~500 g / mol, and the photocurable aromatic ether monomer includes at least one of formulas (1) to (8): Equation (1) Equation (2) Equation (3) Equation (4) Equation (5) Equation (6) Equation (7) Equation (8) The structural formula of the photocurable phenyl monomer is as follows: Formula III: Formula III Among them, R6, R7, R8, R9, R 10 R 11 Each of the following is independently hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted hydroxyalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkoxy, substituted or unsubstituted phenolic hydroxyl, or any one of structural formula IV; The R6, R7, R8, R9, R 10 R 11 At least one is structural formula IV, and the structural formula of structural formula IV is as follows: Formula IV Where * represents the linking site of the aromatic carbon in the compound of structural formula IV, and n2 and n3 are integers from 0 to 20; R 12 It can be hydrogen or methyl; The photocurable aliphatic monomer is a (meth)acrylate with C1 to C20 alkylene groups.

2. The encapsulation ink composition with low curing shrinkage according to claim 1, characterized in that, By weight, it shall include at least the following ingredients: 40 parts of photocurable aliphatic monomers, 30 parts of photocurable aromatic ether monomers, 30 parts of photocurable phenyl monomers, and 2 parts of photoinitiator.

3. The encapsulation ink composition with low curing shrinkage according to claim 1 or 2, characterized in that, The photocurable aliphatic monomer is dodecyl di(meth)acrylate, the photocurable aromatic ether monomer has the structure shown in formula (4), and the photocurable phenyl monomer is polyethylene glycol o-phenyl ether acrylate or ethyl 2-(2-(2-([1,1'-biphenyl]-2-oxo)ethoxy)ethoxy)acrylate.

4. The encapsulation ink composition with low curing shrinkage according to claim 1 or 2, characterized in that, The photocurable aliphatic monomer is dodecyl di(meth)acrylate, the photocurable aromatic ether monomer has the structure shown in formula (3), and the photocurable phenyl monomer is polyethylene glycol o-phenyl ether acrylate or ethyl 2-([1,1'-biphenyl]-2-yl)acrylate.

5. The encapsulation ink composition with low curing shrinkage according to claim 1 or 2, characterized in that, The photocurable aliphatic monomer is dodecyl di(meth)acrylate, the photocurable aromatic ether monomer has the structure shown in formula (2), and the photocurable phenyl monomer is ethyl 2-(2-(2-([1,1'-biphenyl]-2-oxo)ethoxy)ethoxy)acrylate.

6. The encapsulation ink composition with low curing shrinkage according to claim 1 or 2, characterized in that, The photocurable aliphatic monomer is dodecyl di(meth)acrylate, the photocurable aromatic ether monomer is a mixture of the structures shown in formula (3) and formula (4) with a weight ratio of 1:1, and the photocurable phenyl monomer is 2-phenoxyethyl acrylate.

7. The encapsulation ink composition with low curing shrinkage according to claim 1 or 2, characterized in that, The photocurable aliphatic monomers include non-silicon-based (meth)acrylates containing substituted or unsubstituted long-chain alkylene groups.

8. The encapsulation ink composition with low curing shrinkage according to claim 1 or 2, characterized in that, The photoinitiator is one or more of the following: benzoin and its derivatives, benzoyl ketal derivatives, dialkoxyacetophenone, alkyl phenyl ketone, acyl phosphorus oxide, esterified oxime ketone compound, aryl peroxide ester compound, halomethyl aromatic ketone, organic sulfur-containing compound, and benzoyl carboxylate.

9. A method for preparing an encapsulation ink composition with low curing shrinkage as described in any one of claims 1-8, characterized in that, Under light-protected conditions, photocurable aliphatic monomers, photocurable aromatic ether monomers, photocurable phenyl monomers, and photoinitiators are added to a brown light-protected bottle and mixed for 30-80 minutes until homogeneous, thus obtaining an ink composition for encapsulation with low curing shrinkage.

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