Preparation method of low-melting-point polyketone resin

Abstract

The invention belongs to the field of polymer synthesis, and discloses a preparation method of low-melting-point polyketone resin, which adopts a cheap nickel system to catalyze copolymerization of ethylene, propylene and carbon monoxide, and obtains the low-melting-point polyketone resin through precise selection of a catalyst structure and assisted optimization of a polymerization process. A series of high-performance ternary polyketone resin materials with higher propylene insertion rate and lower melting point are simply and efficiently prepared, and the application range of polyketone is widened, so that different use requirements are met. Besides, the synthesis process is friendly, the reaction temperature and pressure are moderate, other expensive cocatalysts do not need to be added, and the overall activity is kept at a higher level of 105g mol <-1 > h <-1 >.

Description

Technical Field

[0001] The present invention belongs to the field of polymer synthesis and relates to a preparation method of a green low-melting polyketone resin. Background Art

[0002] According to the difference in the types of comonomers, aliphatic polyketones can be divided into two main types: binary copolymers (ethylene / CO) and terpolymers (ethylene / propylene / CO). As a new type of engineering plastic, this material system exhibits multi-dimensional performance advantages: it has excellent impact strength, high elastic modulus and excellent wear resistance in terms of mechanical properties; it shows outstanding corrosion resistance, hydrolysis resistance and gas barrier properties in terms of chemical stability; it maintains stable high-temperature tolerance in terms of thermodynamic properties. By controlling the reaction conditions to achieve molecular structure regulation, special grades such as high impact resistance type, high flow type and high modulus type can be prepared to meet the personalized needs of different engineering fields (Brubaker M M, Synthesis and Characterizationof Ethylene / Carbon Monoxide Copolymers, A New Class of Polyketones. Journal ofthe American Chemical Society, 1952). However, the binary alternating copolymer has a processing problem of a narrow processing window between the melting temperature (T m ~260 °C) and the thermal decomposition temperature (T d ~270 °C), and the high crystallinity leads to the deterioration of the thermal properties of the material. To solve the above problems, a third monomer propylene is introduced to construct a terpolymerization system. Experiments show that the ethylene / propylene / CO terpolymer can not only broaden the processing window, but also significantly reduce its crystallinity, thus significantly improving the processing performance and thermal stability.

[0003] The common polyketone products on the market currently are ethylene / propylene / CO terpolymer ketones, such as the POK series products M330, M630, M730, M710, etc. of South Korea's Hyosung. The content of propylene / CO units in them is generally 5-11%, so the corresponding melting points of the materials are generally relatively high, generally between 200-230 °C (David, V. Finding Openings for Polyketone Compounds; PlasticsNewsEurope, 2015), and they are usually used as high-strength and high-temperature-resistant materials in high-end fields such as automobiles and aerospace. However, due to the influence of the high crystallinity of the main chain, the toughness of this material is poor, which limits the application of this material in scenarios such as packaging materials and films. Therefore, assuming that the propylene content in the polyketone structure is further increased while maintaining a relatively high reaction activity, a series of materials with low melting points (<200 °C) are prepared, which will undoubtedly greatly expand the application scope of polyketone materials and thus promote the development of this field. Summary of the Invention

[0004] The purpose of the present invention is to provide a preparation method of a polyketone resin with a low melting point. By using a cheap nickel complex to catalyze the copolymerization of ethylene, propylene and carbon monoxide (CO), and through the precise selection of the catalyst structure and the optimization of the polymerization process, the melting point of the obtained polyketone material can be widely regulated in the range of 100 °C to 200 °C, providing a technical basis for the production of polyketone products suitable for different scenarios.

[0005] The technical solution of the present invention:

[0006] A preparation method of a low melting point polyketone resin,

[0007] The structure of the nickel catalyst used in the preparation method is as follows:

[0008]

[0009] The structure of the polyketone resin is as follows:

[0010]

[0011] Among them, n and m are the degrees of polymerization; 10 3 <n, m < 10 4 ;

[0012] The content of propylene / CO units in the polyketone resin is 10-50%, the melting point is 100-200 °C, and the molecular weight is 60-300 kg mol -1 .

[0013] The synthesis route of the low melting point polyketone resin is as follows:

[0014]

[0015] The steps are as follows: In a glove box, dissolve a nickel catalyst in a solvent to obtain a uniform catalyst solution; transfer the obtained catalyst solution to an autoclave through a feeding tank, start stirring, introduce propylene gas, and after the temperature rises to the required temperature, charge a mixture of ethylene and carbon monoxide with a certain pressure into the autoclave. After the reaction is completed, cool the autoclave. After it returns to room temperature, release the remaining gas in the autoclave, and add a methanol solvent to quench the polymerization reaction. After filtration and drying, a low-melting polyketone resin is obtained.

[0016] Among them, the reaction temperature in the autoclave is 70 - 130 °C, preferably 80 - 90 °C.

[0017] The reaction pressure in the autoclave is 1 - 6 MPa, preferably 3 - 4 MPa.

[0018] The reaction time in the autoclave is 0.5 - 6 h, preferably 3 - 6 h.

[0019] The stirring speed in the autoclave is 100 - 800 r / min, preferably 300 - 500 r / min.

[0020] The molar ratio of ethylene to carbon monoxide used in the reaction in the autoclave is (1 - 5):1, preferably (2 - 4):1.

[0021] The molar ratio of propylene to carbon monoxide used in the reaction in the autoclave is (0.5 - 20):1, preferably (2 - 12):1.

[0022] The solvent is dichloromethane solvent, and the concentration of the nickel catalyst in it is 1 μmol / mL.

[0023] The preparation steps of a tensile low-melting polyketone resin test specimen are as follows:

[0024] (1) Take a polyketone resin with a molecular weight < 200 kg / mol -1 and pre-dry it to remove moisture;

[0025] (2) Set the temperature of the injection molding machine barrel 10 - 15 °C higher than the melting point of the polyketone resin, and the mold temperature is 80 °C. Take the polyketone resin and place it in the barrel to heat it to a molten state;

[0026] (3) Inject the molten polyketone resin into the temperature-controlled mold cavity through high-speed propulsion of the screw, and control the holding pressure time for 10 s; finally, after processing into a dumbbell-shaped polyketone, improve the dimensional stability and mechanical properties of the test specimen through annealing treatment; the length of the specimen is 27.00 mm, the width is 4.00 mm, and the thickness is 2.00 mm.

[0027] The beneficial effects of the present invention:

[0028] (1) Only using olefins and carbon monoxide as raw materials, a high-value low-melting polyketone can be obtained in one step by using an inexpensive nickel-based catalyst, and the activity is generally at a relatively high level of ~10 5 g mol -1 h -1 ;

[0029] (2) The preparation process of polyketone polymers is friendly: the post-treatment process is simple, the reaction temperature and pressure are moderate, and there is no need to add other expensive co-catalysts;

[0030] (3) The content of propylene / CO units in the propylene-based terpolymerized ketone material can be adjusted within the range of 10-50%, and the melting point can be widely adjusted within the range of 100-200 °C. The obtained product can be injection-molded, thus being suitable for different application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is the 13 C NMR diagram of the terpolymerized ketone obtained in Example 1 of the present invention.

[0032] Figure 2 is the DSC diagram of the terpolymerized ketone obtained in Example 2 of the present invention.

[0033] Figure 3 is the tensile property test diagram of the terpolymerized ketone provided in Example 4 of the present invention.

[0034] Figure 4 is the 1 H NMR diagram of the terpolymerized ketone obtained in Example 1 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0035] The following further illustrates the specific embodiments of the present invention in conjunction with the drawings and technical solutions.

[0036] Example 1:

[0037] Add 140 mg of the nickel catalyst used in this specification and 100 mL of refined dichloromethane solvent to a 500 mL autoclave through a feeding tank. Then start stirring and fill the autoclave with the required amount (30-150 g) of propylene gas through a gas flow meter. After that, turn on the heating function of the reaction kettle. When the temperature in the kettle rises to 90 °C, continuously fill the reaction kettle with a mixture of ethylene and carbon monoxide with a ratio of 1:1 at 4.0 MPa. Set the rotation speed to 400 r / min and start timing. The reaction time is 2 h.

[0038] After completion, cool the mechanical reactor under ice-water bath conditions. After restoring to room temperature, release the remaining gas in the reactor, and add methanol solvent to quench the polymerization reaction. Then add a large amount of methanol for precipitation, filter the polymer, and then dry it in a vacuum drying oven at 60 °C for 5 h to obtain a white polymer product. Weigh its mass to calculate the turnover number, use gel permeation chromatography to determine the molecular weight and its distribution of the polymer, and use Varian INOVA-400MHz to determine its 1 1H NMR to obtain the content of propylene / CO units, and use differential scanning calorimetry to test its melting point. The data obtained are shown in Table 1. Charging different masses of propylene has different effects on the propylene insertion ratio and the melting point of the obtained polymer. The content of its propylene / CO units is 11.6-42.1%, and the melting point of the material can be adjusted within the range of 104-199 °C.

[0039] Table 1. Effect of propylene amount on ethylene / propylene / CO terpolymerization a

[0040]

[0041] Note: a Polymerization conditions: 100 μmol nickel catalyst, C2H4 / CO partial pressure ratio of 1 / 1, reaction pressure of 4.0 MPa, reaction at 90 °C for 2 h, 100 mL dichloromethane, 500 mL mechanical reactor, rotation speed of 400 r / min, continuous mode.

[0042] b The propylene insertion ratio is calculated by 1 1H NMR.

[0043] Example 2:

[0044] Add 140 mg of the nickel catalyst used in this specification and 100 mL of refined dichloromethane solvent to a 500 mL autoclave through a feed tank. Then start stirring and charge 50 g of propylene gas into the autoclave through a gas flow meter. After that, turn on the heating function of the reactor. When the temperature in the reactor rises to the required value (70-130 °C), continuously charge a mixture of ethylene and carbon monoxide with a ratio of 1:1 at 4.0 MPa into the reactor. Set the rotation speed to 400 r / min and start timing. The reaction time is 0.5-6 h.

[0045] After completion, cool the mechanical reactor under ice-water bath conditions. After restoring to room temperature, release the remaining gas in the reactor, and add methanol solvent to quench the polymerization reaction. Then add a large amount of methanol for precipitation, filter the polymer, and then dry it in a vacuum drying oven at 60 °C for 5 h to obtain a white polymer product. Weigh its mass to calculate the turnover number, use gel permeation chromatography to determine the molecular weight and its distribution of the polymer, and use Varian INOVA-400MHz to determine its 11H NMR was used to obtain the content of propylene / CO units, and differential scanning calorimetry was applied to measure its melting point. The obtained data are shown in Table 2. Different reaction temperatures and times have different effects on the propylene insertion ratio and melting point of the resulting polymer. The content of propylene / CO units is 17.8 - 28.1%, and the melting point of the material can be adjusted within the range of 156 - 184 °C.

[0046] Table 2. Effects of reaction temperature and time on ethylene / propylene / CO terpolymerization a

[0047]

[0048] Note: a Polymerization conditions: 100 μmol nickel catalyst, C2H4 / CO partial pressure ratio of 1 / 1, reaction pressure of 4.0 MPa, propylene charge of 50 g, 100 mL dichloromethane, 500 mL mechanical autoclave, rotation speed of 400 r / min, continuous mode.

[0049] b The propylene insertion ratio was calculated by 1 1H NMR.

[0050] Example 3:

[0051] 140 mg of the nickel catalyst used in this specification and 100 mL of refined dichloromethane solvent were added to a 500 mL autoclave through a feeding tank. Subsequently, stirring was started, and 50 g of propylene gas was charged into the autoclave through a gas flow meter. The heating function of the reaction kettle was turned on. When the temperature in the kettle reached 90 °C, a mixed gas of ethylene and carbon monoxide with a ratio of (1 - 4):1 at different pressures (1 - 4 MPa) was continuously charged into the reaction kettle. The rotation speed was set to 400 r / min and timing was started, and the reaction time was 2 h.

[0052] After completion, the mechanical reaction kettle was cooled under ice-water bath conditions. After returning to room temperature, the remaining gas in the kettle was released, and methanol solvent was added to quench the polymerization reaction. Then, a large amount of methanol was added for precipitation, and the polymer was filtered. Subsequently, it was dried in a vacuum drying oven at 60 °C for 5 h to obtain a white polymer product. Its mass was weighed to calculate the turnover number. Gel permeation chromatography was used to determine the molecular weight and its distribution of the polymer, and Varian INOVA-400 MHz was used to measure its 1 1H NMR to obtain the content of propylene / CO units, and differential scanning calorimetry was applied to measure its melting point. The obtained data are shown in Table 2. Different ethylene / CO mixed gas ratios and total pressures have different effects on the propylene insertion ratio and melting point of the resulting polymer. The content of propylene / CO units is 16.2 - 23.2%, and the melting point of the material can be adjusted within the range of 176 - 196 °C.

[0053] Table 3. Influence of Ethylene / CO Gas Ratio and Total Pressure on Ethylene / Propylene / CO Terpolymerization a

[0054]

[0055]

[0056] Note: a Polymerization conditions: 100 μmol nickel catalyst, polymerization reaction temperature of 90 °C, 50 g of propylene, reaction time of 2 h, 100 mL of dichloromethane, 500 mL mechanical autoclave, continuous mode.

[0057] b The propylene insertion ratio is calculated by 1 1H NMR.

[0058] c The rotation speed is 600 r / min.

[0059] Example 4:

[0060] Take polyketone powder with a molecular weight < 200 kg / mol -1 and pre-dry it to remove moisture. Set the temperature of the injection molding machine barrel 10 - 15 °C higher than the polymer melting point, and the mold temperature is 80 °C. Take 3 g of polymer powder and place it in the barrel to heat it to the molten state. Inject the melt into the temperature-controlled mold cavity through high-speed screw propulsion, and precisely control the holding pressure time for 10 s to reduce internal stress; finally, after the polyketone product is processed into a dumbbell shape, perform annealing treatment to improve the dimensional stability and mechanical properties of the specimen. The length of the specimen is 27.00 mm, the width is 4.00 mm, and the thickness is 2.00 mm. Clamp the specimen symmetrically in the upper and lower fixtures of the testing machine, ensure that the axis of the dumbbell-shaped sample is aligned with the center line of the fixture to avoid eccentric load. Set the strain rate of the testing machine to 20 mm / min, then start the testing machine, the crossbeam starts to move, detect the stress-strain curve in real time, observe whether there is any abnormality, record the values of the elastic stage, yield stage, strengthening stage, and fracture stage of the sample, and finally end the tensile test and remove the fractured specimen. The specific data of the tensile properties of the ternary polyketone are shown in Table 4.

[0061] Table 4. Tensile Property Parameters of Ternary Polyketone

[0062]

[0063]

Claims

1. A preparation method of a low-melting-point polyketone resin, characterized in that, The synthesis route of the low-melting-point polyketone resin is as follows: The steps are as follows: In a glove box, dissolve the nickel catalyst in a solvent to obtain a uniform catalyst solution; transfer the obtained catalyst solution to an autoclave through a feed tank, start stirring, introduce propylene gas, and after the temperature rises to the required temperature, charge a mixture of ethylene and carbon monoxide with a certain pressure into the autoclave. After the reaction is completed, cool the autoclave, and after it returns to room temperature, release the remaining gas in the autoclave, and add a methanol solvent to quench the polymerization reaction. After filtration and drying, the low-melting-point polyketone resin is obtained.

2. The preparation method according to claim 1, characterized in that, The structure of the nickel catalyst described above is as follows:

3. According to the preparation method described in claim 1, characterized in that, The reaction temperature in the autoclave is 70 - 130 °C; The reaction pressure in the autoclave is 1 - 6 MPa; The reaction time in the autoclave is 0.5 - 6 h; The stirring speed in the autoclave is 100 - 800 r / min; The molar ratio of ethylene to carbon monoxide used in the reaction in the autoclave is (1 - 5):1; The molar ratio of propylene to carbon monoxide used in the reaction in the autoclave is (0.5 - 20):1; The solvent described above is dichloromethane solvent, and the concentration of the nickel catalyst in it is 1 μmol / mL.

4. According to the preparation method described in claim 1, characterized in that, The reaction temperature in the autoclave is 80 - 90 °C; The reaction pressure in the autoclave is 3 - 4 MPa; The reaction time in the autoclave is 3 - 6 h; The stirring speed in the autoclave is 300 - 500 r / min; The molar ratio of ethylene to carbon monoxide used in the reaction in the autoclave is (2 - 4):1; The molar ratio of propylene to carbon monoxide used in the reaction in the autoclave is (2 - 12):

1.

5. According to the preparation method described in claim 1, characterized in that, The structure of the polyketone resin described above is as follows: Among them, n and m are degrees of polymerization; 10 3 <n, m < 10 4 ; The propylene / CO unit content in the polyketone resin is 10 to 50%, the melting point is 100 to 200 °C, and the molecular weight is 60 to 300 kg / mol -1 .

6. According to the preparation method described in claim 1, characterized in that, The preparation steps of the test specimen by stretching the low-melting-point polyketone resin are as follows: (1) Take polyketone resin with molecular weight < 200 kg / mol -1 and perform pre-drying to remove moisture; (2) Set the temperature of the injection molding machine barrel 10 - 15 °C higher than the melting point of the polyketone resin, and the mold temperature is 80 °C. Take the polyketone resin and place it in the barrel to heat it to a molten state; (3) Inject the molten polyketone resin into the temperature-controlled mold cavity by high-speed propulsion of the screw, control the holding pressure time for 10 s, and finally process it into a polyketone product with the required shape.

Images