Hyperbranched polymer, preparation method and application

Abstract

The present invention relates to a novel hyperbranched polymer containing an oxetane group and a preparation method and application thereof. The hyperbranched polymer uses 3,3-dibromomethyloxetane and phenol and benzoic acid derivatives as raw materials, is prepared by a one-pot method, and uses oxetane as a connecting group inside and is mainly composed of phenolic hydroxyl groups outside; then the remaining phenolic hydroxyl groups are further etherified and cyclocarbonated with oxetane halides and epoxy halides, thereby preparing a hyperbranched polymer having cationic polymerizable functional groups inside and outside the hyperbranched structure. The raw materials of the present invention are easy to obtain, the steps are simple, the purification is easy, and it can be prepared on a large scale. Participating in a photocuring formula can increase the photocuring speed of the formula, reduce the formula viscosity, and reduce the photocuring shrinkage rate, and has good application prospects in the fields of photocuring coatings, inks, adhesives, etc.

Description

Technical Field

[0001] The present invention belongs to the technical field of new material organic chemicals, and specifically relates to a type of hyperbranched polymer containing cationic polymerizable groups both inside and outside, and a preparation method and application thereof, in particular, the application in photoinduced cationic polymerization, especially cationic photoinduced polymerization requiring high speed, low viscosity and low shrinkage. Background Art

[0002] At present, due to the simple synthesis process of hyperbranched polymers, they can be synthesized in one step, and have good solubility, small solution and melt viscosity, a large number of terminal functional groups and intramolecular voids. Therefore, hyperbranched polymers have unique advantages over dendritic polymers and have broad application prospects in drug carriers, polymer catalysts, curing agents, solvent-free coatings and polymer processing aids. However, the usual structure of hyperbranched polymers is that the core or the periphery is modified with functional groups to achieve their functions.

[0003] In the field of photocuring, cationic photocuring systems have the advantages of being unaffected by oxygen inhibition and having small shrinkage in cured volume. The active diluent monomers used are mainly vinyl ether compounds, epoxy compounds, oxetane, and cyclic carbonate compounds. Vinyl ether monomers have high polymerization activity, but their hardness, wear resistance, chemical resistance and other properties are poor, and they cannot be used as hard coating agents and protective films for various substrates. Epoxy monomers can obtain cured products with good heat resistance, adhesion and chemical resistance, but the monomer reaction activity is low. In comparison, oxetane monomers have high reaction activity, and their cured products have excellent physical properties, so they are more and more widely used in curing compositions. In particular, the use of oxetane monomers and epoxy monomers (to combine the advantages of both) has become a common form in cationic photocuring systems. Cyclic carbonates, mainly 1,3-dioxolane monomer structures, are of great significance to the realization of the "dual carbon" goal because they utilize carbon dioxide in their synthesis. Moreover, this type of monomer is an expandable monomer, and the shrinkage rate of the photocurable cationic polymerization system in which it participates can be reduced or even increased, which is very necessary for volume-sensitive applications, such as optical adhesives used in the electronics industry.

[0004] Therefore, the present application designs and prepares a class of hyperbranched polymers containing cationic polymerizable groups both inside and outside. Such a hyperbranched structure gives the photocurable system high activity and high performance, and the unique system synthesis of the peripheral modified cyclic carbonate further realizes the absorption of carbon dioxide and the effect of volume expansion during photocuring, which has great application potential in cationic polymerization photocurable compositions. Summary of the invention

[0005] In view of the shortcomings of the prior art, the primary object of the present invention is to provide a class of hyperbranched polymers containing cationic polymerizable groups both inside and outside.

[0006] The second object of the present invention is to provide a method for preparing a class of hyperbranched polymers containing cationically polymerizable groups both inside and outside.

[0007] The third object of the present invention is to provide the use of the above-mentioned hyperbranched polymer containing cationic polymerizable groups both inside and outside, especially for cationic photocuring and in fields sensitive to volume shrinkage.

[0008] To achieve the above object, the solution of the present invention is:

[0009] A novel hyperbranched polymer, specifically a hyperbranched polymer containing cationic polymerizable groups both inside and outside, characterized in that: the inside is a hyperbranched structure prepared using 3,3-dibromomethyloxetane, phenol and benzoic acid derivatives as raw materials, specifically synthesized by a one-pot A2+CB2 type reaction; the outside is to further introduce or prepare cationic polymerizable groups by using phenolic hydroxyl groups to form ether bonds.

[0010] Further, A2 is 3,3-dibromomethyloxetane, B represents phenolic hydroxyl group, and C represents carboxylic acid on the benzene ring. When the phenolic hydroxyl group and the carboxyl group are connected to a single benzene ring, CB2 is a dihydroxybenzoic acid derivative; when the phenolic hydroxyl group and the carboxyl group can also be connected to different benzene rings, CB2 is a mixture, which is a compound of two or more of monohydroxyisophthalic acid, gallic acid, trimesic acid, and pyrogallol. The result of the compounding is that the average number of functional groups on the final benzene ring is still one carboxylic acid group and two phenolic hydroxyl groups. Preferably, CB2 is 3,5-dihydroxybenzoic acid or 3,4-dihydroxybenzoic acid.

[0011] Furthermore, the specific results of various phenol and benzoic acid derivatives are shown below.

[0012]

[0013] Further, the external cationically polymerizable group is oxetane or 1,3-dioxolane.

[0014] Further, a type of hyperbranched polymer structure containing cationic polymerizable groups both inside and outside, the structure of the first step product is a branched structure with phenolic hydroxyl groups on the outside, preferably, 3,5-dihydroxybenzoic acid is used as the CB2 group, and the schematic diagram of the obtained polymer (ignoring the influence of molecular weight) is as follows:

[0015]

[0016] Furthermore, a type of hyperbranched polymer structure containing cationic polymerizable groups both inside and outside, the peripheral group is oxetane, or 1,3-dioxolane ketone, and its basic molecular structure is shown in the figure below (ignoring the influence of molecular weight):

[0017]

[0018] Furthermore, the present invention also provides a method for preparing the hyperbranched polymer containing cationic polymerizable groups both inside and outside, characterized in that the steps are as follows:

[0019]

[0020] Step (1): in a certain organic solvent system, 3,3-bisbromomethyloxetane (A2 monomer) and polyhydroxybenzoic acid monomer or composition (CB2 monomer) are added to a reactor in a certain molar ratio, an alkali catalyst is added, and the mixture is reacted at 60-100° C. for 12-48 hours, inorganic salts are filtered out, most of the organic solvent is evaporated off, and then washed with water, and the precipitate is filtered out to obtain a hyperbranched polymer HBP-0 with oxetane inside, which is a white or light brown solid powder;

[0021] Step (2a): After the reaction is completed, no purification is performed, and a base catalyst and a certain amount of 3-bromomethyl-3-ethyloxetane are directly added, and the reaction is continued at 60-100° C. for 36-48 hours. The reaction is stopped after the hydroxyl value is less than 3, and the inorganic salt is filtered out. Most of the organic solvent is evaporated and washed with water. The precipitate is filtered to obtain a hyperbranched polymer HBP-A having both internal and terminal oxetane. n , white or light brown solid powder;

[0022] Furthermore, the organic solvent is one or more of N,N-dimethylformamide, dimethyl sulfoxide, toluene, xylene or tetrahydrofuran; more preferably, it is N,N-dimethylformamide.

[0023] Step (2b): After the reaction is completed, the catalyst and a certain amount of epibromohydrin or epichlorohydrin are directly added without purification, and the reaction is continued at 60-100° C. for 36-48 hours. The reaction is stopped after the hydroxyl value is tested to be less than 3, the inorganic salt is filtered out, most of the organic solvent is evaporated, and then washed with water. The precipitate is filtered out to obtain a hyperbranched polymer with oxetane inside and ethylene oxide outside:

[0024]

[0025] Further, the organic solvent is one or more of N,N-dimethylformamide, dimethyl sulfoxide, toluene, xylene or tetrahydrofuran; more preferably N,N-dimethylformamide;

[0026] Furthermore, the base catalyst is an inorganic base such as potassium carbonate, sodium hydroxide, potassium hydroxide, etc.; more preferably, it is potassium carbonate.

[0027] Step (3): Add the catalyst (0.05 molar equivalent of epoxy group) to the epoxide HBP-B-0 (calculated as 1 equivalent per epoxy group) dissolved in an organic solvent at room temperature. Pass CO2 gas (about 1 atm) at 45°C with stirring. After 48 hours, the reaction is completed and the mixture is washed with water. The aqueous layer is extracted twice with an organic solvent, and the combined organic layers are dried over sodium sulfate, filtered, and evaporated in vacuo to obtain a colorless or light yellow product HBP-B.

[0028] Further, the catalyst in step (3) is tetrabutylammonium bromide; more preferably, it is 1,8-diazabicyclo[5.4.0]-7-undecene hydroiodide. The organic solvent is chloroform or ethyl acetate.

[0029] Furthermore, a method for preparing a type of hyperbranched polymer containing cationic polymerizable groups both inside and outside is provided, characterized in that the reaction molar ratio of A2 and CB2 is controlled at 1:1 to 1.5:1.

[0030] Furthermore, a method for preparing a hyperbranched polymer containing cationic polymerizable groups both inside and outside is provided, characterized in that during the preparation step (2), the amount of monohalide added is the total amount of hydroxyl and carboxyl groups in CB2 minus the amount of bromide in A2. In order to ensure sufficient reaction, the amount of monohalide can be appropriately increased by 10 to 20%.

[0031] The present invention also provides the use of the hyperbranched polymer containing cationic polymerizable groups both inside and outside, especially the use as a multifunctional resin in cationic photoinitiated polymerization. The resin can be prepared by cationic photoinitiation of sulfonium salts, iodonium salts and the like.

[0032] Furthermore, the photopolymerization system of a type of hyperbranched polymer containing cationic polymerizable groups both inside and outside is characterized by comprising one or more hyperbranched polymers containing cationic polymerizable groups both inside and outside, and commercial monomers, oligomers, resins or a mixture or copolymer of the three, different photoinitiators and a small amount of additives, etc., which are appropriately added as required.

[0033] Furthermore, in the formula described in the present invention, the commercial monomers, oligomers, and resins are selected from one or more of bisphenol A epoxy, alicyclic epoxy, dicyclopentadiene epoxy, diaminodiphenylmethane epoxy, aminophenol epoxy, naphthalene epoxy, novolac epoxy, biphenyl epoxy, hydrogenated biphenyl epoxy, aliphatic epoxy, oxetane derivatives, etc.; the ratio of the prepared monomer compound derived from isosorbide dicarbonate and the oligomer is 1:1 to 1:9.

[0034] Furthermore, in the formulation of the present invention, the photoinitiator includes but is not limited to aromatic diazonium salts, iodonium salts, sulfonium salts and aromatic ferrocenium salts, etc. In order to promote the use efficiency of light sources of different wavelengths, different sensitizers may also be added, including but not limited to anthracene sensitizers, pyrazoline sensitizers, and coumarin sensitizers; the amount of sensitizer and initiator added is 1% to 5%, and the ratio of the two is adjusted as needed.

[0035] Furthermore, in the formulation of the present invention, various additives include any components such as inorganic fillers, organic fillers, colorants, other additives and solvents. Among them, the colorant is selected from pigments or dyes. Other additives include ultraviolet absorbers, light stabilizers, flame retardants, leveling agents or defoamers.

[0036] The present invention further provides a class of hyperbranched polymers containing cationic polymerizable groups both inside and outside, which are characterized by being able to be used in various photocurable coatings, inks, adhesives and various photoinitiated polymerization systems such as 3D printing and electronic packaging, especially in photopolymerization systems that require rapid curing and reduced viscosity.

[0037] Furthermore, the invention can be used for reducing volume shrinkage.

[0038] Hyperbranched polymers that contain cationic polymerizable groups both inside and outside are listed below (regardless of branching degree and molecular weight):

[0039]

[0040] Due to the adoption of the above scheme, the beneficial effects of the present invention are:

[0041] 1. Hyperbranched polymers containing cationic polymerizable groups both inside and outside have a structure similar to that of dendritic polymers. They can be prepared by a one-pot method and can effectively reduce the viscosity in the formulation system, making construction easier.

[0042] 2. During the photocuring process, the hyperbranched polymer containing cationic polymerizable groups both inside and outside the molecule can undergo ring-opening polymerization inside and outside the molecule. The participating photocuring system has a fast curing speed and the photocured product has a high hardness.

[0043] 3. The photocurable coatings in which hyperbranched polymers containing cationic polymerizable groups both inside and outside participate are odorless, have small volume shrinkage, and have strong adhesion to the substrate.

[0044] 4. Hyperbranched polymers containing cationic polymerizable groups both inside and outside, especially polymers with cyclic carbonates on the outside, use carbon dioxide in the preparation process to achieve carbon fixation, which is very meaningful for the realization of the "dual carbon" goal;

[0045] 5. Dendritic polymers containing cyclic carbonates further reduce the volume shrinkage of the curing system based on the low volume shrinkage of oxetane. Under appropriate proportions, the volume expansion of the polymer can be achieved. They have great potential in volume-sensitive applications such as photocuring adhesives. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of the hyperbranched polymer HBP-A1 prepared in Example 1 of the present invention;

[0047] Figure 2 These are the GPC elution curves of the hyperbranched polymers HBP-A1, HBP-A5 and HBP-A6 prepared in Examples 1, 6 and 7 of the present invention.

[0048] Figure 3 The infrared spectrum of the hyperbranched polymer HBP-A1 prepared in Example 1 of the present invention and its synthetic raw materials; DETAILED DESCRIPTION

[0049] The technical solution of the present invention is further described in detail below in conjunction with several preferred embodiments and drawings. This embodiment is implemented on the premise of the technical solution of the invention, and a detailed implementation method and specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments.

[0050] Unless otherwise specified, the experimental materials used in the following examples can be purchased from conventional biochemical reagent companies.

[0051] The technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] Embodiment 1:

[0053] A novel hyperbranched polymer HBP-A1 capable of cation polymerization, the preparation method of which comprises the following steps:

[0054] 1) 3,5-dihydroxybenzoic acid (0.622 g, 4.5 mmol) and K2CO3 (1.38 g, 10 mmol) were mixed in a three-necked flask with DMF (25.0 mL) and stirred at 80°C for 10 minutes. Then 3,3-bisbromomethyl-1-oxetane (1.098 g, 4.5 mmol) was quickly added to the reaction mixture at a molar ratio of 1:1. Stir at 80°C for 24 hours.

[0055] 2) After the reaction, the reaction was not purified, and the type A functional monomer 3-bromomethyl-3-ethyloxetane (0.895 g, 5.4 mmol) and K2CO3 (0.829 g, 6.75 mmol) were directly added, and the reaction was continued at 80°C for 48 h. When the hydroxyl value was tested to be less than 3, the reaction was stopped, the inorganic salt was filtered out, and DMF was removed by vacuum distillation. The residue was dissolved in THF, precipitated into excess distilled water, and the precipitate was re-dissolved in THF. The above dissolution-precipitation cycle was repeated three times. The precipitate was filtered and dried overnight in a vacuum oven at 50°C. Finally, 1.17 g of hyperbranched polymer HBP-A1 was obtained as a white solid powder with a yield of 85.92%.

[0056] Figure 1 is the H NMR spectrum of the prepared hyperbranched polymer HBP-A1;

[0057] Figure 2 The GPC elution curve of the prepared hyperbranched polymer HBP-A1 is given.

[0058] Figure 3 This is the infrared spectrum of the prepared hyperbranched polymer HBP-A1 and its synthetic raw materials.

[0059] Embodiment 2:

[0060] A novel hyperbranched polymer HBP-B1 capable of cation polymerization, the preparation method of which comprises the following steps:

[0061] 1) 3,5-dihydroxybenzoic acid (0.622 g, 4.5 mmol) and K2CO3 (1.38 g, 10 mmol) were mixed in a three-necked flask with DMF (25.0 mL) and stirred at 80°C for 10-15 minutes. Then 3,3-bisbromomethyl-1-oxetane (1.427 g, 5.85 mmol) was quickly added to the reaction mixture at a molar ratio of 1:1. Stir at 80°C for 24 hours.

[0062] 2) After the reaction, the functional monomer epibromopropane (0.296 g, 2.16 mmol) and K2CO3 (0.553 g, 4 mmol) were directly added without purification, and the reaction was continued at 80°C for 48 h. The inorganic salt was filtered off, and DMF was removed by vacuum distillation. The residue was dissolved with THF, precipitated into excess distilled water, and the precipitate was re-dissolved with THF. The above dissolution-precipitation cycle was repeated three times. The final precipitate was washed with excess distilled water and dried overnight in a vacuum oven at 50°C to obtain an intermediate.

[0063] 3) Tetrabutylammonium bromide (0.035 g, 0.11 mmol) was added to the intermediate product dissolved in ethyl acetate (25.0 mL) at room temperature, and CO2 gas (about 1 atm) was introduced under stirring at 45°C. After 48 hours, the reaction was completed and the mixture was rinsed with water. The aqueous layer was extracted twice with an organic solvent, and the combined organic layers were dried over sodium sulfate, filtered, and evaporated in vacuo to finally obtain 1.16 g of hyperbranched polymer HBP-B1 as a white solid powder with a yield of 84.65%.

[0064] Example 3-13: The different target products were prepared by changing the type of CB2 and the feed ratio of step (1). The specific feed and molecular structure characteristics, reaction time, etc. of the first step are shown in the following table and compared with Examples 1 and 2:

[0065] Table 1. Feed, yield and molecular weight characterization of different examples

[0066]

[0067] The GPC elution curves of the hyperbranched polymers HBP-A5 and HBP-A6 prepared in Example 6 and Example 7 are shown in FIG. Figure 2 shown.

[0068] Embodiment 14:

[0069] Recipe photopolymerization experiment:

[0070] A plurality of polymerization test samples were prepared according to the following weight percentages: 0-30% of the hyperbranched polymer in Example 1 and Example 2; 10-60% of the resin EPOX; 3% of the photoacid-generating initiator, and two photoinitiators were selected for compounding. The specific formula is shown in Table 1.

[0071]

[0072] Table 2. Light curing formula

[0073]

[0074] Take a portion of the above mixture, heat it to 80°C, stir it thoroughly until it is completely dissolved, and then evenly cast it into a white polytetrafluoroethylene mold (length×width×height 5cm×0.5cm×0.2cm). Use a 365nm LED surface light source (Uvata, Shanghai) to vertically irradiate the sample at a distance of 10cm for 60s. The finger pressure scratching method is used to determine whether the sample is completely cured.

[0075] Example 15: Photocuring coating performance test experiment:

[0076] The coating containing different monomers prepared in Example 12 was scraped and then photocured to obtain a photocured film (not containing other plastic substrates). The pencil hardness was measured according to GB / T 6739-2006, the adhesion was measured according to GB / T9286-1998, the tensile properties were measured according to GB / T 16421-1996, and the curing shrinkage was measured according to GB / T24148.9. The test results are shown in Table 3.

[0077] Table 3 Photocuring coating properties

[0078] formula Pencil hardness Adhesion Tensile Strength Volume shrinkage Recipe 1 2H 4B 28.8MPa 5.6％ Recipe 2 2H 4B 33.7MPa 4.5％ Recipe 3 3H 5B 52.2MPa 4.0％ Recipe 4 2H 4B 41.0MPa 5.2％ Recipe 5 3H 5B 58.3MPa 4.3％ Recipe 6 3H 5B 59.7MPa 4.0％ Recipe 7 3H 5B 54.2MPa 4.1％

[0079] The above description of the embodiments is to facilitate the understanding and use of the present invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments. Improvements and modifications made by those skilled in the art based on the principles of the present invention without departing from the scope of the present invention should be within the protection scope of the present invention.

Claims

1. A hyperbranched polymer, characterized in that: The preparation method of the hyperbranched polymer HBP-A1 comprises the following steps: 1) Mix 3,5-dihydroxybenzoic acid and K2CO3 in a three-necked flask containing 25.0 mL of DMF and stir at 80°C for 10 minutes; wherein: 3,5-dihydroxybenzoic acid: 0.622 g, 4.5 mmol; K2CO3: 1.38 g, 10 mmol; Then 3,3-bisbromomethyl-1-oxetane was added at a molar ratio of 1:1, 1.098 g, 4.5 mmol, and quickly added to the reaction mixture; Stir at 80°C for 24 hours; 2) After the reaction, the functional monomer 3-bromomethyl-3-ethyloxetane and K2CO3 were directly added without purification, wherein the amount of 3-bromomethyl-3-ethyloxetane added was 0.895 g, 5.4 mmol; the amount of K2CO3 added was 0.829 g, 6.75 mmol; The reaction was continued at 80°C for 48 hours. When the hydroxyl value was less than 3, the reaction was stopped, the inorganic salt was filtered off, and DMF was removed by vacuum distillation. The residue was dissolved in THF and precipitated into excess distilled water. The precipitate was redissolved in THF. The above dissolution-precipitation cycle was repeated three times. The precipitate was filtered and dried in a vacuum oven at 50°C overnight; Finally, the hyperbranched polymer HBP-A1 was obtained in the form of white solid powder.

Images