Preparation method of high-hydroxyl-content hydroxypropyl polymethacrylate

Abstract

The invention discloses a preparation method of high-hydroxyl-content hydroxypropyl polymethacrylate, and relates to the technical field of high polymer material synthesis and surface treatment.The preparation method comprises the steps that 1, a polymer synthesis process is conducted, specifically, PHPMA synthesis comprises the following steps that 1, 100 g of HPMA is dissolved in 300 g of an ethyl alcohol / ethyl acetate mixed solvent (2: 1); (2) adding 0.8 g of AIBN and 0.3 g of DDMAT, heating to 60 DEG C under the protection of nitrogen, and reacting for 1 hour; (3) heating to 75 DEG C, reacting for 4 hours, and curing at 85 DEG C for 1 hour; (4) cooling, pouring n-hexane precipitate, and carrying out vacuum drying to obtain a white polymer (Mn = 28,000, equal to 1.32); step 2, a coating application process: coating the PET film by the following specific steps: (1) preparing PHPMA into a 10% ethyl acetate solution, and adding 1% HDI; and (2) coating a PET (Polyethylene Terephthalate) film (the thickness is 50 microns), and testing after curing: the surface energy is equal to 68.5 dyn / cm, and the water contact angle is equal to 8.2 degrees. The problem of hydroxyl loss is solved by accurately controlling the polymerization process, and the surface energy of the thin film is permanently improved by utilizing the design of the cross-linked coating.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of high-molecular material synthesis and surface treatment, in particular to a preparation method of high-hydroxyl-content polyhydroxypropyl methacrylate. BACKGROUND

[0002] At present, the surface energy of plastic films (such as PE, PP and PET) is low (usually <= 35 dyn / cm), which leads to the difficulty in printing, film plating and bonding processes, and the traditional corona treatment effect is unstable and short in time; the existing acrylate coating has problems such as insufficient hydroxyl density, poor adhesion or poor water resistance, and the like. Hydroxypropyl methacrylate (HPMA) monomer contains a side chain hydroxyl group, but the conventional polymerization is prone to crosslinking or uneven distribution of the hydroxyl group, leading to unstable hydrophilicity of the coating. SUMMARY

[0003] The application aims to provide a preparation method of high-hydroxyl-content polyhydroxypropyl methacrylate to solve the problems in the background art.

[0004] To achieve the above-mentioned purpose, the application provides the following technical scheme: a preparation method of high-hydroxyl-content polyhydroxypropyl methacrylate, comprising the following steps: Step one: polymer synthesis process, the specific steps of synthesizing PHPMA are as follows: (1) 100g HPMA is dissolved in 300g of ethanol / ethyl acetate (2:1) mixed solvent; (2) 0.8g AIBN and 0.3g DDMAT are added, and the temperature is raised to 60 DEG C under nitrogen protection for 1h; (3) the temperature is raised to 75 DEG C for 4h, and then 85 DEG C for 1h; (4) after cooling, pour into n-hexane for precipitation, and vacuum dry to obtain white polymer (Mn=28,000, D=1.32); Step two: coating application process, the specific steps of coating PET film are as follows: (1) PHPMA is prepared into a 10% ethyl acetate solution, and 1% HDI is added; (2) the coating is applied to a PET film (thickness 50 mu m), and after curing, the surface energy is 68.5 dyn / cm (the untreated PET is 43 dyn / cm), and the water contact angle is 8.2 DEG (the untreated PET is 72 DEG).

[0005] Preferably, the key parameters in step one include the following: (1) solvent: ethanol / ethyl acetate (3:1~1:1); (2) Initiator: Azobisisobutyronitrile (AIBN) 0.5-1.5 wt%; (3) Chain transfer agent: DDMAT (2-dodecyl trithiocarbonate) 0.1-0.5 wt%; (4) Molecular weight control: Mn=10,000-50,000 g / mol.

[0006] Preferably, in the step 1, when storage is performed during the synthesis process, the storage is performed in a sealed and light-shielding manner, and the temperature of the storage layer is controlled to maintain the storage temperature at -20°C, and the reaction conditions are controlled, including the solvent system, temperature and time, and oxygen control, wherein the solvent system includes a preferred solvent and a water solvent polymerization, and the temperature and time are specifically monitored during the synthesis process. The monitoring method is regular sampling and monitoring, and the reaction time is controlled, and the oxygen control is specifically deoxygenation operation, and at least three "freezing-vacuuming-nitrogen filling" cycles are performed.

[0007] Preferably, post-treatment and passivation are performed in step 1, and the post-treatment and passivation include termination reaction and polymer passivation, wherein the termination reaction is cooled in an ice bath and then the cooling material is injected, and the cooling is continued until the polymer can be exposed to the air, and the polymer passivation includes dialysis (cut-off Mw <10kDa: dialysis bag (MWCO 3.5-7kDa) is dialyzed against deionized water for 3 days, cut-off Mw>50kDa: ultrafiltration centrifugation (MWCO 30kDa)), precipitation method (dropping the reaction solution into icy ether / acetone (10 times the volume), centrifuging and collecting the precipitate (repeated 3 times)) and impurity removal verification (TLC or UV detection of no monomer / CTA residue).

[0008] Preferably, in step 1, a key performance verification scheme is formulated, and the key verification scheme includes molecular weight and distribution, structure confirmation and biocompatibility, wherein the molecular weight and distribution include GPC test: PEG / PMMA is used as the standard sample, DMF or water (containing 0.1M NaNO3) is used as the mobile phase, wherein the structure is confirmed as : δ=1.0-1.2ppm (-CH3), δ=2.8-3.2ppm (-N-CH2-), δ=3.4-3.8ppm (-CH-OH), among which the biocompatibility is related to the critical aggregation concentration (CAC): pyrene fluorescence probe method, protein adsorption: BCA method to detect serum protein adsorption.

[0009] Preferably, a safety precaution plan is formulated in step 1, and the safety precaution plan is specifically: (1) Toxicity protection: HPMA monomer is irritating to mucous membranes. Wear a gas mask (N95 grade) and goggles during operation; (2) Polymerization explosion-proof: the reaction system is not more than 50% of the volume of the container, using a jacketed reactor to control the temperature; (3) Waste treatment: un-polymerized monomers need to be discarded after quenching with 10% NaOH solution.

[0010] Preferably, the step one is carried out by free radical polymerization in the presence of chain transfer agent DDMAT in alcohol / ester mixed solvent, and the reaction temperature includes the following: (1) First stage: 55-65℃ initiation reaction; (2) Second stage: 70-80℃ main polymerization; (3) Third stage: 80-90℃ curing.

[0011] Preferably, the coating liquid formula in step two is PHPMA 10wt% + HDI crosslinking agent (0.5-2wt%) + ethyl acetate solvent, and the coating method is micro-gravure roll coating (wet film thickness 5-20μm)→80℃ pre-drying 3min→120℃ curing 1min.

[0012] Compared with the prior art, the present application has the following advantages: The present application solves the problem of hydroxyl loss by precise control of the polymerization process, and simultaneously realizes the persistent improvement of the surface energy of the film by the design of the crosslinked coating. The high conversion rate (>98%) polymerization of HPMA is realized by the selection of the solvent system + initiator gradient temperature control, while the self-condensation of hydroxyl is inhibited, and a linear polymer with narrow molecular weight distribution (Ð<1.5) and hydroxyl retention rate >95% is obtained. BRIEF DESCRIPTION OF DRAWINGS

[0013] Fig. 1 The present application provides an overall structure schematic diagram for the embodiments; Fig. 2 The present application provides an infrared spectrum of PHPMA for the embodiments. DETAILED DESCRIPTION

[0014] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0015] Please refer to Figs. 1-2 The present application provides a technical solution: a preparation method of high-hydroxyl-content polyhydroxypropyl methacrylate, comprising the following steps: Step one: polymer synthesis process, the specific steps for synthesizing PHPMA are as follows: (1) 100 g HPMA was dissolved in 300 g of ethanol / ethyl acetate (2:1) mixed solvent; (2) 0.8 g AIBN, 0.3 g DDMAT were added, and the temperature was raised to 60°C under nitrogen protection for 1 h; (3) The temperature was raised to 75°C for 4 h, and then aged at 85°C for 1 h; (4) After cooling, precipitate into n-hexane, and vacuum dried to obtain white polymer (Mn=28,000, Ð=1.32); Step two: coating application process, PET film coating implementation steps are as follows: (1) PHPMA was prepared into 10% ethyl acetate solution, and 1% HDI was added; (2) Coated on PET film (thickness 50 μm), and after curing, the surface energy was 68.5 dyn / cm (untreated PET was 43 dyn / cm), and the water contact angle was 8.2° (untreated was 72°).

[0016] The key parameters of step one include the following: (1) Solvent: ethanol / ethyl acetate (3:1~1:1); (2) Initiator: azobisisobutyronitrile (AIBN) dosage 0.5-1.5 wt%; (3) Chain transfer agent: DDMAT (2-dodecyltrithiocarbonate) 0.1-0.5 wt%; (4) Molecular weight control: Mn=10,000-50,000 g / mol.

[0017] In step one, during the storage in the synthesis process, the storage was carried out in a sealed and light-shielded manner, and the storage layer temperature was controlled to maintain the storage temperature at-20°C, and the reaction conditions were controlled, including the solvent system, temperature and time, and oxygen control. The solvent system includes the preferred solvent and water-solvent polymerization, and the temperature and time are specifically monitoring the temperature during the synthesis process by periodic sampling, and the time during the reaction is controlled, and the oxygen control is specifically deoxidation operation, and at least three "freezing-vacuum-nitrogen filling" cycles.

[0018] The post-treatment and passivation in the step one include termination reaction and polymer passivation, wherein the termination reaction is injected with cooling material after ice bath cooling, and the polymer passivation includes dialysis method (Mw<10kDa: dialysis bag (MWCO 3.5-7kDa) against deionized water for 3 days, Mw>50kDa: ultrafiltration centrifugation (MWCO 30kDa)), precipitation method (drop the reaction solution into ice ether / acetone (10 times the volume), centrifugal collection of the precipitate (repeat 3 times)) and impurity removal verification (TLC or UV detection of monomer / CTA residual).

[0019] The critical performance verification scheme in the step one includes molecular weight and distribution, structure confirmation and biocompatibility, wherein the molecular weight and distribution include GPC test: PEG / PMMA as standard sample, DMF or water (containing 0.1M NaNO3) as mobile phase, wherein the structure confirmation is : δ=1.0-1.2ppm (-CH3), δ=2.8-3.2ppm (-N-CH2-), δ=3.4-3.8ppm (-CH-OH), and the biocompatibility is specifically critical aggregation concentration (CAC): pyrene fluorescence probe method, protein adsorption: BCA method for detecting serum protein adsorption.

[0020] The safety attention scheme in the step one is specifically: (1) Toxicity protection: HPMA monomer has irritation to mucous membrane, and a gas mask (N95 level) and goggles are worn during operation; (2) Polymer explosion prevention: the reaction system does not exceed 50% of the volume of the container, and a jacketed reactor is used for temperature control; (3) Waste treatment: the un-polymerized monomer is quenched with 10% NaOH solution and then discarded.

[0021] The free radical polymerization in the step one is carried out in alcohol / ester mixed solvent in stages under the presence of chain transfer agent DDMAT, and the reaction temperature includes the following: (1) First stage: 55-65℃ initiation reaction; (2) Second stage: 70-80℃ main polymerization; (3) Third stage: 80-90℃ curing.

[0022] The coating liquid formula in the step two is specifically: PHPMA 10wt% + HDI crosslinking agent (0.5-2wt%) + ethyl acetate solvent, and the coating method is specifically: micro-gravure roll coating (wet film thickness 5-20μm) → 80℃ pre-baking 3min → 120℃ curing 1min.

[0023] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting; it is not intended to exclude myriad other embodiments of the present application that other inventors can develop based on the same general inventive concepts embodied by the described embodiments. That is, although the present application is described in terms of particular embodiments and illustrative figures, it should be apparent that the scope of the present application is not limited to these specific embodiments.

[0024] While the embodiments of the application have been shown and described herein, it will be understood by those skilled in the art that many changes, modifications, substitutions and alterations to these embodiments can be made without departing from the principles and spirits of the application, and it is intended that the scope of the application be limited solely by the scope of the appended claims and the equivalents thereof.

Claims

1. A method for preparing high hydroxyl content polyhydroxypropyl methacrylate, characterized in that The following steps are involved: Step 1: Polymer synthesis process, the specific steps for synthesizing PHPMA are as follows: (1) Dissolve 100 g of HPMA in 300 g of ethanol / ethyl acetate (2:1) mixed solvent; (2) Add 0.8 g AIBN and 0.3 g DDMAT, and heat to 60 °C under nitrogen for 1 h; (3) Heat to 75°C for 4 hours, then mature at 85°C for 1 hour; (4) After cooling, pour n-hexane into the solution for precipitation and vacuum dry to obtain a white polymer (Mn=28,000, Ð=1.32); Step 2: Coating application process, the specific steps for coating PET film are as follows: (1) Prepare PHPMA into a 10% ethyl acetate solution and add 1% HDI; (2) Coated on PET film (thickness 50 μm), tested after curing: surface energy = 68.5 dyn / cm, water contact angle = 8.2°.

2. The method for preparing a high hydroxyl content polyhydroxypropyl methacrylate according to claim 1, characterized in that: The key parameters of step 1 include the following: (1) Solvent: ethanol / ethyl acetate (3:1~1:1); (2) Initiator: Azobisisobutyronitrile (AIBN) 0.5-1.5 wt%; (3) Chain transfer agent: DDMAT (2-dodecyl trithiocarbonate) 0.1-0.5 wt%; (4) Molecular weight control: Mn=10,000-50,000 g / mol.

3. The method for preparing a high hydroxyl content polyhydroxypropyl methacrylate according to claim 1, characterized in that: When storing during the synthesis process in the step 1, the storage is carried out in a sealed and light-shielded manner, and the temperature of the storage layer is controlled to maintain the storage temperature at -20°C, and the reaction conditions are controlled, including the solvent system, temperature, time and oxygen control, wherein the solvent system includes a preferred solvent and a water solvent polymerization, and the temperature and time are specifically monitored during the synthesis process. The monitoring method is regular sampling and monitoring, and the reaction time is controlled. The oxygen control is specifically deoxygenation operation, and at least three "freezing-vacuuming-nitrogen filling" cycles are performed.

4. The method for preparing a high hydroxyl content polyhydroxypropyl methacrylate according to claim 1, characterized in that: In the step 1, post-treatment and passivation are performed, and the post-treatment and passivation include termination reaction and polymer passivation, wherein the termination reaction is cooled in an ice bath and then the cooling material is injected, and the cooling is continued until the polymer can be exposed to the air. The polymer passivation includes dialysis (cut-off Mw <10 kDa: dialysis bag (MWCO 3.5-7 kDa) against deionized water for 3 days, cut-off Mw>50 kDa: ultrafiltration centrifugation (MWCO 30 kDa)), precipitation method (dropping the reaction solution into icy ether / acetone (10 times the volume), centrifuging and collecting the precipitate (repeated 3 times)) and impurity removal verification (TLC or UV detection of no monomer / CTA residue).

5. The method for preparing polyhydroxypropyl methacrylate with high hydroxyl content according to claim 1, wherein: In step 1, a key performance verification plan is formulated, and the key verification plan includes molecular weight and distribution, structure confirmation and biocompatibility. The molecular weight and distribution include GPC test: PEG / PMMA is used as the standard sample, DMF or water (containing 0.1M NaNO3) is used as the mobile phase, and the structure is confirmed as follows: : δ=1.0-1.2ppm (-CH3), δ=2.8-3.2ppm (-N-CH2-), δ=3.4-3.8ppm (-CH-OH), among which the biocompatibility is related to the critical aggregation concentration (CAC): pyrene fluorescence probe method, protein adsorption: BCA method to detect serum protein adsorption.

6. The method for preparing polyhydroxypropyl methacrylate with high hydroxyl content according to claim 1, wherein: In step 1, a safety precaution plan is formulated, and the safety precaution plan is specifically as follows: (1) Toxicity protection: HPMA monomer is irritating to mucous membranes. Wear a gas mask (N95 grade) and goggles during operation; (2) Polymerization explosion prevention: The reaction system does not exceed 50% of the container volume, and a jacketed reactor is used for temperature control; (3) Waste disposal: Unpolymerized monomers must be quenched with 10% NaOH solution and discarded.

7. The method for preparing polyhydroxypropyl methacrylate with high hydroxyl content according to claim 1, wherein: In the step 1, in the presence of a chain transfer agent DDMAT, free radical polymerization is carried out in an alcohol / ester mixed solvent by controlling the temperature in stages, and the reaction temperature includes the following: (1) The first stage: 55-65℃ to initiate the reaction; (2) The second stage: main polymerization at 70-80℃; (3) The third stage: aging at 80-90℃.

8. The method for preparing polyhydroxypropyl methacrylate with high hydroxyl content according to claim 1, wherein: The coating solution formula in step 2 is specifically: PHPMA 10wt% + HDI crosslinker (0.5-2wt%) + ethyl acetate solvent, and the coating method is specifically: micro-gravure roller coating (wet film thickness 5-20μm) → 80°C pre-bake for 3 minutes → 120°C curing for 1 minute.

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