CN114011105A

CN114011105A - Purification method of packaging ink composition

Info

Publication number: CN114011105A
Application number: CN202111213283.4A
Authority: CN
Inventors: 洪海兵; 杨楚峰; 沈馨; 王士昊
Original assignee: Hangzhou Foster Electronic Materials Co ltd
Current assignee: Hangzhou Foster Electronic Materials Co ltd
Priority date: 2021-10-19
Filing date: 2021-10-19
Publication date: 2022-02-08

Abstract

The invention relates to the field of film packaging ink, in particular to a purification method of a packaging ink composition, which comprises the following steps: (a) dissolving the ink composition in an organic solvent to form an ink solution; (b) washing the ink solution with high-purity water, standing, separating liquid, separating the washing liquid, and testing the resistivity of the washing liquid until the resistivity is unchanged; (c) and (3) carrying out column chromatography on the ink solution, and then sequentially carrying out reduced pressure distillation and vacuum desolventization to obtain the required ink composition. The method overcomes the defect that the method for purifying the electronic grade chemicals in the prior art cannot be applied to the ink composition for film packaging, can effectively purify the ink composition, greatly reduces the content of metal ions in the ink composition, can effectively avoid the structural change of the ink caused by high-temperature biochemistry, and is beneficial to the industrial production of the ink.

Description

Purification method of packaging ink composition

Technical Field

The invention relates to the field of film packaging ink, in particular to a purification method of a packaging ink composition.

Background

Organic Light-Emitting Diodes (OLEDs for short) have the characteristics of all solid-state, active Light emission, high brightness, high contrast, ultra-thin and ultra-Light, low cost, low power consumption, no view angle limitation, wide working temperature range and the like, can be manufactured on a flexible, Light and durable plastic substrate, can realize flexible display in the true sense, and is a technology which can best meet the requirements of people on future displays.

Compared with Liquid Crystal Display (LCD), the organic electroluminescent device (OLED) has the advantages of low driving voltage, high brightness and luminous efficiency, wide luminous viewing angle and high response speed; in addition, the flexible printed circuit board has the advantages of being ultrathin, capable of being manufactured on a flexible panel and the like. Is known as the third generation flat panel display technology.

As organic electroluminescent diodes for next-generation flat panel display applications, organic photoelectric semiconductor materials are required to have: 1. high luminous efficiency; 2. excellent electron and hole stability; 3. a suitable emission color; 4. excellent in workability. The currently applied light emitting diodes mainly comprise organic small molecule light emitting diodes (OLEDs), Polymer Organic Light Emitting Diodes (POLED), organic phosphorescent light emitting diodes (PHOLEDs), and organic thermal excitation delayed light emitting materials (TADFs). The organic phosphorescent light-emitting diode material has the light-emitting mechanisms of singlet excitation state (fluorescence) and triplet excitation state (phosphorescence), and the quantum efficiency and the light-emitting efficiency are 3-4 times of those of fluorescent OLED materials (J. Am. chem. Soc., 2001, 123: 4304-4312), so that the phosphorescent material obviously has much higher light-emitting efficiency than small molecular fluorescent materials, the generated heat is reduced, and the competitiveness of OLED display panels is enhanced. This makes it possible to have OLED displays or lighting as a whole beyond LCD displays and conventional light sources.

However, the largest problem of the OLED at present is that the lifetime of the OLED is shorter than that of the LCD, and the lifetime of the OLED is only about 5000 hours, which is significantly inferior to that of the LCD. The service life of the OLED device is a key problem which puzzles numerous experts and scholars of the OLED at present and is a bottleneck which restricts the development of the OLED industry. To solve the problem completely in technical level, it still has certain difficulty, and it also needs certain time to shorten the difference between the two lifetimes.

The factors influencing the service life of the OLED device are many, and physical factors such as the structure of the device, the circuit driving mode and the like exist; there are also chemical factors such as oxidation of the metal cathode, crystallization of the organic material, etc. Although the failure mechanism of OLEDs is not completely understood, there are many studies that indicate that the purity of the OLED material is an important factor in the lifetime of OLEDs.

The purity of organic materials is considered to be one of the most fundamental prerequisites to assess whether it can be used in OLEDs. But is one of the most easily viewed problems. The leader of the development of phosphorescent materials Universal Display Corporation (UDC), whose product red phosphorescent guest emitter material (RD07) was measured for different purities of its lifetime, found that organic materials of different purities had a considerable effect on lifetime. However, each apparatus for determining the purity of organic materials has its limit, and therefore, it is necessary to repeatedly perform a purification operation on organic materials before the OLED module is fabricated, and it is also important to remove a trace amount of ions present in the organic materials.

Due to the development of optoelectronic technologies, the requirements on the quality of electronic devices are becoming more and more strict, and the factors affecting electronic devices are most critical in terms of the purity of the key electronic grade chemicals used therein. Most of the organic materials have the characteristic that the melting point is higher than the cracking temperature, so that the organic materials cannot be effectively purified by using a common purification method (such as a rectification method). However, since the electronic grade chemicals have high melting point and biochemical characteristics, the sublimation purification technology with high temperature and high vacuum degree is undoubtedly the best physical separation and purification method, so that the electronic grade chemicals with high purity can be obtained by purification by using the technology, so as to meet and improve the photoelectric characteristics of electronic devices. However, since the ink composition for thin film encapsulation cannot be purified to remove organic and inorganic impurities through a sublimation process because its terminal group contains a photosensitive or thermosensitive group, there is a strong need to find another method to solve such problems.

Disclosure of Invention

The present invention is directed to overcoming the disadvantages of the prior art in which methods for purifying electronic grade chemicals are not applicable to ink compositions for thin film encapsulation, and therefore provides a method for purifying an ink composition to overcome the aforementioned disadvantages.

In order to achieve the purpose, the invention is realized by the following technical scheme:

a method of purifying an encapsulated ink composition, comprising the steps of:

(a) dissolving the ink composition in an organic solvent to form an ink solution;

(b) washing the ink solution with high-purity water, standing, separating liquid, separating the washing liquid, and testing the resistivity of the washing liquid until the resistivity is unchanged;

(c) and (3) carrying out column chromatography on the ink solution, and then sequentially carrying out reduced pressure distillation and vacuum desolventization to obtain the required ink composition.

According to the purification method of the packaging ink composition, firstly, trace ions in the ink composition are dissolved in water in a water washing mode, meanwhile, the principle that an organic solvent is incompatible with water is utilized, so that the trace ions are separated from the ink solution, and the removal rate of the ions in the ink solution is judged by carrying out resistivity test on a washing liquid containing water and the trace ions obtained after liquid separation. The resistivity of the washing liquid is gradually increased along with the increase of the washing times and the liquid separation times until the resistivity is inconvenient after three times of washing, which indicates that the extraction of trace ions in the ink solution is completed to a lower value.

The purification method adopts a method of controlling the ion content in the crude product by adopting the resistivity of the washing liquid, thereby realizing the purpose of monitoring the quality of the crude product of the raw material.

In addition, after the trace ions in the ink solution are reduced to a lower value by a water washing mode, the ink solution is further purified by a column chromatography mode, and after the column chromatography treatment, the trace metal ions remained in the ink solution can be adsorbed by polar silica gel filled in a chromatographic column. Residual metal ions in the ink solution after column chromatography can be completely removed, and the purified packaging ink can be obtained through reduced pressure distillation and vacuum desolventization.

Compared with the prior art, the purification method of the ink has the advantage of low-temperature treatment, can effectively avoid structural change of the ink caused by high-temperature biochemistry, and is favorable for industrial production of the ink.

Preferably, in step (a) of the present invention, the ink composition is composed of a photo-curable monomer or polymer, a photoinitiator and an auxiliary agent.

Wherein: 1) the above-mentioned photocurable monomer or polymer includes:

photocurable monomers or polymers containing photocurable functional groups (e.g., vinyl, (meth) acrylate, epoxy).

The photocurable monomer can be a monofunctional monomer, a difunctional monomer, a multifunctional monomer, or a mixture, wherein the "monofunctional" monomer refers to a monomer having one photocurable functional group, and similarly, the "difunctional" monomer refers to a monomer having two photocurable functional groups, and the "multifunctional" monomer refers to a monomer having three or more photocurable functional groups.

The photocurable monomer according to the present invention is preferably a monomer having two to four photocurable functional groups. The photocurable monomer may also be a monofunctional curable monomer, a mixture of a difunctional curable monomer and a polyfunctional curable monomer, or a polymer. In the mixture, the monofunctional curable monomer and the bifunctional curable monomer or the polyfunctional curable monomer or the polymer may be mixed in a range of 1:0.1 to 1: 10.

The photo-curable monomer or polymer is at least one of the following species: monofunctional (meth) acrylates of C1 to C30 mono-or polyols, difunctional (meth) acrylates of C2 to C30 mono-or polyols, polyfunctional (meth) acrylates of C3 to C30 mono-or polyols.

The monofunctional photocurable monomer can be generally classified into alkyl acrylate, hydroxy (meth) acrylate, and (meth) acrylate and vinyl monomers having a cyclic structure or a benzene ring, according to the difference in structure, and specifically, there are: lauryl Acrylate (LA), ethoxyethoxyethoxyethyl acrylate (EOEOEA) -KPX A007, Butyl Acrylate (BA), hydroxyethyl acrylate and isobornyl acrylate, ethoxylated tetrahydrofurfuryl acrylate (THF (EO) A) -KPX A015, methacrylate phosphates, and isobornyl methacrylate.

The bifunctional monomers mostly have a dihydric alcohol structure, and mainly comprise ethylene glycol diacrylate, propylene glycol diacrylate and other glycol diacrylates. The concrete structure is as follows: diethylene glycol diacrylate (DEGDA), triethylene glycol diacrylate (TEGDA), ethylene glycol diacrylate, polyethylene glycol (200) diacrylate [ PEG (200) DA]Polyethylene glycol (400) diacrylate [ PEG (400) DA ]]Polyethylene glycol (600) diacrylate [ PEG (600) DA ]]Neopentyl glycol diacrylate and propoxy neopentyl glycol diacrylate, 1, 6-hexanediol diacrylate (HDDA), 1, 4-butanediol diacrylate (BDDA), 20 (ethoxy) bisphenol A diacrylate [ BPA (EO)₂₀DA]Glycerol Diacrylate (TPGDA) and polyfunctional trimethylolpropane triacrylate (TMPTA), pentaerythritol triacrylate (PETA), trimethylolpropane triol triacrylate (TMPTMA), trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, pentaerythritol triacrylate and propoxylated pentaerythritol propenol, ditrimethylolpropane tetraacrylate, triethylene glycol dimethacrylate, long chain aliphatic glycidyl ether acrylate, dipentaerythritol hexaacrylate, tripropylene glycol diacrylate, diethylene glycol diacrylate Phthalate (PDDA), ethoxylated trimethylolpropane triol triacrylate [ TMP (EO) TMA]Propoxylated trimethylolpropane triol triacrylate [ TMP (PO) TMA)]Propoxylated glycerol triacrylate [ G (PO) TA]Tris (2-hydroxyethyl) isocyanurate triacrylate, ethoxylated neopentyl glycol methoxy monoacrylate [ TMP (PO) MEDA]And the like.

2) The above-mentioned photoinitiator includes a radical photoinitiator and a cationic photoinitiator

With respect to initiation of the polymerization process, various embodiments of the organic thin film ink compositions of the present application can utilize various types of photoinitiators to initiate the polymerization process.

In various embodiments, the photoinitiator is present in an amount of from about 1% to about 20% by weight, for example from about 1% to about 10% by weight. This includes embodiments in which the photoinitiator is preferably present in an amount of about 3% to about 8% by weight.

Further preferred include embodiments wherein the photoinitiator is present in an amount of from about 3% to about 5% by weight. However, amounts outside of these ranges may also be used.

The photoinitiator may be a type I or type II photoinitiator. Type I photoinitiators undergo radiation-induced cleavage to generate two free radicals, one of which is reactive and initiates polymerization. Type II photoinitiators undergo a radiation-induced conversion to an excited triplet state.

The excited triplet state molecules then react with the ground state molecules to generate free radicals that initiate polymerization. The photoinitiator may include triazines, acetophenones, benzophenones, phosphorous initiators and mixtures thereof.

Examples of triazine initiators include 2,4, 6-trichloro-s-triazine, 2-phenyl-4, 6-bis (trichloromethyl) -s-triazine, 2- (3',4' -dimethoxystyryl) -4, 6-bis (trichloromethyl) -s-triazine, 2- (4' -methoxynaphthyl) -4, 6-bis (trichloromethyl) -s-triazine, 2- (p-methoxyphenyl) -4, 6-bis (trichloromethyl) -s-triazine, 2- (p-tolyl) -4, 6-bis (trichloromethyl) -s-triazine, 2-biphenyl-4, 6-bis (trichloromethyl) -s-triazine, bis (trichloromethyl) -6-styryl-s-triazine, 2- (naphthalen-1-yl) -4, 6-bis (trichloromethyl) -s-triazine, 2- (4-methoxynaphthalen-1-yl) -4, 6-bis (trichloromethyl) -s-triazine, 2, 4-trichloromethyl (piperonyl) -6-s-triazine, 2,4- (trichloromethyl- (4' -methoxystyryl) -6-triazine, and mixtures thereof.

Examples of acetophenone initiators include 2,2' -diethoxyacetophenone, 2' -dibutoxyacetophenone, 2-hydroxy-2-methylpropiophenone, p-tert-butyltrichloroacetophenone, p-tert-butyldichloroacetophenone, 4-chloroacetophenone, 2' -dichloro-4-phenoxyacetophenone, 2-methyl-1- (4- (methylthio) phenyl) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, and mixtures thereof.

Examples of benzophenone initiators include benzophenone, benzoylbenzoic acid methyl, 4-phenylbenzophenone, hydroxybenzophenone, acrylated benzophenone, 4' -bis (dimethylamino) benzophenone, 4' -dichlorobenzophenone, 3' -dimethyl-2-methoxybenzophenone and mixtures thereof.

In addition, the photoinitiator is a cationic photoinitiator, and includes, but is not limited to, one or more of diaryliodonium salts, triarylsulfonium salts, diazonium salts, alkylsulfonium salts, iron arene salts, sulfonyloxy ketones, and triarylsiloxy ethers, and more preferably one or more of diaryliodonium salts and triarylsulfonium salts.

3) In order to improve the film forming property of the photocurable encapsulating composition, it is preferable that the photocurable encapsulating composition further comprises an auxiliary agent.

The auxiliary agent comprises one or more of a polymerization inhibitor, a surfactant, an antioxidant, a heat stabilizer, a defoaming agent and a leveling agent. It will be appreciated that other adjuvants may also be included in the composition. The above-mentioned additives can be selected from the corresponding additives commonly used in the packaging film in the prior art, and are not listed here.

Preferably, the ratio of the mass of the ink to the volume of the organic solvent in the step (a) is 1.0/2 to 1.0/10 g/ml.

Preferably, the organic solvent in step (a) is any one of dichloromethane, carbon tetrachloride, chloroform, tetrachloroethane, toluene, xylene, ethyl acetate, cyclohexane, petroleum ether, and methyl tert-butyl ether.

The organic solvent selected in the invention is an organic solvent which is not mutually soluble with water, and can prevent the ink from being mixed into the water to cause the loss of the ink on the basis of effectively extracting impurity ions in the ink solution.

Preferably, the high purity water in step (b) is water having a resistivity of more than 10 M.OMEGA.cm until the resistivity of the washing solution is unchanged by three consecutive tests.

Preferably, the high purity water in the step (b) has a resistivity of more than 10 M.OMEGA.cm or more until the resistivity of the washing liquid generated by the continuous washing is not changed.

The resistivity of the high-purity water is more than 10M omega cm, the sensitivity of the resistivity to trace ions in the ink is high, and the resistivity of a water body is greatly reduced after the trace ions in the ink are transferred into the high-purity water.

Generally speaking, when the resistivity of the solution obtained by three times of washing is basically unchanged, namely the terminal point, the resistivity reaches 18M omega cm, and if the requirement is met, the solution is generally washed for 5 to 10 times. If the requirement that the resistivity of the solution washed for three times is basically unchanged cannot be met, the washing times are expanded until the requirement is met.

More preferably, the resistivity of the high purity water is greater than 18M Ω · cm or more.

Preferably, the volume ratio of the high purity water to the ink solution in the step (b) is 1/3 to 4/1.

Further preferably, the volume ratio of the moderately pure water to the ink solution is 1/3 to 1/1.

Preferably, the washing time in the step (b) is 0.2 to 10 hours, and the standing time is 0.5 to 2.0 hours.

Further preferably, the washing time in the step (b) is 0.2-0.5 h, and the standing time is 0.5-1.0 h.

Preferably, step (c) is carried out under an inert gas blanket.

Further preferably, the inert gas includes any one of nitrogen, argon, and helium.

Preferably, the column chromatography temperature in step (c) is 20 to 100 ℃, more preferably 20 to 50 ℃.

At this temperature, the stability of the ink composition is high, and thus no change in the physicochemical properties is caused under such conditions.

Preferably, the column chromatography in step (c) is filled with a silica gel adsorbent, and the silica gel adsorbent is modified silica gel containing substituent propyl mercaptan.

The silica gel adsorbent used in column chromatography in the invention takes activated silica gel as a carrier and a framework, and the activated silica gel reacts with the propyl mercaptan containing the substituent group to form the propyl mercaptan containing the substituent group modified silica gel with strong chelating ability. Compared with the traditional silica gel adsorbent, the ink composition is modified by the propanethiol on the basis of activated silica gel, and the sulfur element in the silica gel can form a stable chelate with metal ions, so that residual trace metal ions in the ink can be effectively adsorbed, and the concentration of the metal ions in the ink composition is effectively reduced.

Preferably, the pressure of the reduced pressure distillation in the step (c) is 0.05 to 0.10MPa, and the temperature of the reduced pressure distillation is 20 to 50 ℃.

The temperature is controlled to be 20-50 ℃ in the reduced pressure distillation process, the self-aggregation of the ink in the reduced pressure distillation process can be effectively prevented, and the problem of incomplete concentration exists when the temperature is lower than the temperature range.

Therefore, the invention has the following beneficial effects:

(1) the ink composition can be effectively purified, and the content of metal ions in the ink composition is greatly reduced;

(2) the method of controlling the ion content in the crude product by adopting the resistivity of the washing liquid in the purification process realizes the purpose of monitoring the quality of the crude product of the raw material;

(3) compared with the prior art, the purification method of the ink has the advantage of low-temperature treatment, can effectively avoid structural change of the ink caused by high-temperature biochemistry, and is favorable for industrial production of the ink.

Drawings

FIG. 1 is a flow chart of a purification process of an ink composition.

Detailed Description

The invention is further described with reference to the drawings and the specific embodiments. Those skilled in the art will be able to implement the invention based on these teachings. Moreover, the embodiments of the present invention described in the following description are generally only some embodiments of the present invention, and not all embodiments. Therefore, all other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without any creative effort shall fall within the protection scope of the present invention.

The flow chart given by fig. 1 can be seen:

the process flow route of the invention is as follows: adding the ink composition into a three-mouth bottle, adding an organic solvent, stirring and heating until the initiator and the monomer polymer are completely dissolved; pouring the solution into a beaker, adding high-purity water with the resistivity more than 10M omega cm, stirring and washing for a few minutes, standing, separating liquid and separating purified water; repeating the steps until the resistivity of the separated washing liquid is determined to be unchanged for three times; and under the protection of inert gas, adsorbing the solution by a chromatographic column containing a modified silica gel adsorbent containing substituent propyl mercaptan to further remove ions, pouring the obtained solution into a distillation flask, carrying out reduced pressure distillation, keeping the temperature at 20-50 ℃ for concentration to obtain a crude product, and maintaining the temperature of the crude product at 20-50 ℃ by a vacuum pump to carry out vacuum desolventization to obtain the required ink composition.

Example 1:

table 1 example 1 ink composition recipe table

Step a:

adding 500g of crude printing ink and 1000ml of ethyl acetate into a three-mouth bottle, and starting stirring; the temperature is raised to 30 ℃, and when the crude product is completely dissolved, the heating is stopped.

Step b:

when the temperature is reduced to room temperature, pouring the solution into a beaker, adding 500ml of high-purity water, stirring and washing for 30min, standing for 10min, and separating liquid; adding 1000ml of high-purity water, stirring and washing for 10min, standing for 10min, and separating liquid; this was repeated 5 more times; the resistivity of the washing solution was stabilized at a level of 15 M.OMEGA.cm in the continuous measurement from the 6 th time.

Step c:

and under the protection of inert gas, adsorbing the solution by a chromatographic column containing an adsorbent to further remove ions, pouring the obtained solution into a distillation flask, carrying out reduced pressure distillation, keeping the temperature at 35 ℃ for concentration to obtain a crude product, maintaining the temperature of the crude product at 30 ℃ by a vacuum pump, carrying out vacuum desolventization to obtain the required ink composition, wherein the yield is 95%, and testing the ion content of the ink composition.

Example 2:

table 2 example 2 ink composition recipe table

Step a:

Step b:

when the temperature is reduced to room temperature, pouring the solution into a beaker, adding 500ml of high-purity water, stirring and washing for 30min, standing for 10min, and separating liquid; adding 1000ml of high-purity water, stirring and washing for 10min, standing for 10min, and separating liquid; this was repeated 7 more times; the resistivity of the washing solution was stabilized at a level of 15.5 M.OMEGA.cm in the continuous measurement from the 8 th time.

Step c: and under the protection of inert gas, adsorbing the solution by a chromatographic column containing an adsorbent to further remove ions, pouring the obtained solution into a distillation flask, carrying out reduced pressure distillation, keeping the temperature at 35 ℃ for concentration to obtain a crude product, maintaining the temperature of the crude product at 30 ℃ by a vacuum pump, carrying out vacuum desolventization to obtain the required ink composition, wherein the yield is 90%, and testing the ion content of the ink composition.

TABLE 3 test results for ion content

And annotating: 1.-mg/kg = -ppm = a few million.

2. Testing an instrument: ICP-MS.

N.d. = undetected (less than method detection limit).

As can be seen from Table 3, the ion content of the ink composition after purification treatment is significantly reduced, and the process is simple and easy to implement, and is easy to realize industrial production.

It will be understood by those skilled in the art that the present invention is not limited to the above-described embodiments and drawings, and various modifications, changes, and alterations can be made without departing from the spirit and scope of the present invention. Accordingly, these examples are provided for illustration only, and are not to be construed as limiting the invention in any way.

Claims

1. A method of purifying an encapsulated ink composition, comprising the steps of:

2. The method of claim 1, wherein the ratio of the mass of the ink to the volume of the organic solvent in step (a) is 1.0/2 to 1.0/10 g/ml.

3. The method of purifying a sealing ink composition as claimed in claim 1, wherein the organic solvent in the step (a) is any one of dichloromethane, carbon tetrachloride, chloroform, tetrachloroethane, toluene, xylene, ethyl acetate, cyclohexane, petroleum ether, and methyl t-butyl ether.

4. A method for purifying a sealing ink composition as claimed in claim 1, wherein the high purity water in the step (b) is water having a resistivity of more than 10M Ω -cm until the resistivity of the washing liquid generated by the continuous washing is not changed.

5. A method for purifying a sealing ink composition as claimed in claim 1 or 4, wherein the volume ratio of the high purity water to the ink solution in the step (b) is 1/3-4/1.

6. The method of claim 5, wherein the washing time in step (b) is 0.2-10 hours, and the standing time is 0.5-2.0 hours.

7. A method of purifying a packaged ink composition according to claim 1, wherein step (c) is performed under an inert gas atmosphere.

8. The method of purifying a sealing ink composition as claimed in claim 7, wherein the column chromatography temperature in the step (c) is 20 to 100 ℃.

9. A purification method of a sealing ink composition as claimed in claim 1 or 8, wherein the column chromatography in step (c) is filled with silica gel adsorbent, and the silica gel adsorbent is modified silica gel containing substituent propyl mercaptan.

10. The method of claim 1, wherein the vacuum distillation in step (c) is performed under a pressure of 0.05 to 0.10MPa and at a temperature of 20 to 50 ℃.