High and low temperature resistant CPET composite material and preparation method thereof

Abstract

The application discloses a high and low temperature resistant CPET composite material and a preparation method thereof, relates to the technical field of polymer composites, and aims to improve the high and low temperature resistance of the CPET material and improve the impact resistance of the CPET material. The toughening agent of the CPET material is modified in the preparation process of the CPET material. The silane structure and the long carbon chain structure of the acrylate are introduced on the surface of the talcum powder, the dispersibility of the talcum powder in the PET is effectively improved, and the particle size of the talcum powder is limited in order to improve the crystallization performance of the CPET. After calcination, the talcum powder is sieved through a 2500-mesh sieve, and the particle size of the talcum powder is less than 5 microns. Therefore, the talcum powder can play a part of nucleating agent, and the acrylate group structure grafted on the surface of the talcum powder can improve the thermal stability of the material, so that the material can avoid thermal degradation in the heat processing process, and the mechanical properties of the material after forming are further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer composite materials, in particular to a high and low temperature resistant CPET composite material and a preparation method thereof. Background Art

[0002] Polyethylene terephthalate (PET) is a colorless, non-toxic plastic material widely used in food packaging. CPET is a special form of PET that can be given higher temperature resistance by controlling its crystallization. However, current CPET materials have poor impact resistance, which seriously restricts their scope of use. In addition, the nucleating agents and some toughening agents in CPET materials also have a significant impact on the crystallization properties of CPET. Therefore, it is necessary to improve these phenomena to meet existing market demand. Summary of the Invention

[0003] The object of the present invention is to provide a high and low temperature resistant CPET composite material and a preparation method thereof, so as to solve the problems raised in the prior art.

[0004] To achieve the above object, the present invention provides the following technical solution: a method for preparing a high and low temperature resistant CPET composite material, comprising the following steps:

[0005] S1. Preparation of modified toughening agent;

[0006] S11 talc was placed in an air atmosphere, calcined, after calcination, cooled to room temperature, ground and dispersed, after passing through a 2500 mesh sieve, the sieved powder was collected to obtain calcined talc;

[0007] S12. Calcined talc was dispersed in a sodium hydroxide solution, heated to 90-95°C, stirred for 4-8 hours, and then centrifuged to separate the precipitate. The solution was washed with deionized water until neutral, and then vacuum dried to constant weight. The solution was then added to an ethanol-water solution, and acetic acid was added to adjust the pH to 4-6.5. KH570 was then added to the solution, and the solution was heated to 80-90°C, stirred for 4-8 hours, and then centrifuged to separate the precipitate. The precipitate was washed with anhydrous ethanol 2-3 times and then vacuum dried to constant weight to obtain silane-modified talc.

[0008] S13. The silane-modified talc prepared in step S12 is dispersed in tetrahydrofuran, and after being uniformly dispersed by ultrasonic vibration, it is added dropwise to 1,4-bis(dimethylsilyl)benzene dispersed with chloroplatinic acid catalyst. Stirring is continued during the dropwise addition process. The temperature of the reaction solution is controlled to be maintained at 55-65°C. After stirring under reflux for 2-4 hours, the precipitate is separated by filtration, washed with clean tetrahydrofuran 2-3 times, and then vacuum dried to constant weight to obtain silane-modified talc.

[0009] S14. Redisperse the silicon-hydrogen-modified talc in tetrahydrofuran (THF), ultrasonically disperse the powder until uniform, and then add it dropwise to tetraethylene glycol dimethacrylate (TETA) containing a chloroplatinic acid catalyst. Stir continuously during the addition. Maintain the reaction system at 60-66°C. Reflux and stir in the dark for 2-8 hours. Centrifuge the precipitate, wash it 2-3 times with clean THF, and dry it to constant weight to obtain a modified toughening agent.

[0010] S2 by weight ratio, were weighed PET resin, modified toughening agent, nucleating agent, antioxidant, flame retardant, which were added to a high-speed mixer, mixed uniformly to obtain a mixture;

[0011] S3. The mixed material is added to a twin-screw extruder, melt-extruded and pelletized to obtain a high and low temperature resistant CPET composite material.

[0012] Furthermore, in step S11, during calcination, the calcination temperature is 850-900° C., and the calcination time is 30-45 minutes.

[0013] Furthermore, in step S12, the sodium hydroxide solution has a sodium hydroxide concentration of 10-30 wt%.

[0014] Furthermore, in step S12, the mass ratio of the calcined talc powder, the ethanol aqueous solution, and KH570 is 5: (40-60): (1-10) in parts by weight;

[0015] Wherein, the ethanol concentration in the ethanol aqueous solution is 60-75wt%.

[0016] Furthermore, in step S13, the mass ratio of the silane-modified talc powder, the chloroplatinic acid catalyst, and 1,4-bis(dimethylsilyl)benzene is 5:(0.02-0.05):(0.5-5) in parts by weight.

[0017] Furthermore, in step S14, the mass ratio of the silicon-hydrogen modified talc powder, the chloroplatinic acid catalyst, and tetraethylene glycol dimethacrylate is 5: (0.03-0.05): (1-10) in parts by weight.

[0018] Furthermore, in step S2, the contents of each component are 85-90 parts of PET resin, 8-15 parts of modified toughening agent, 0.5-1 part of nucleating agent, 0.5-0.8 part of antioxidant, and 1.5-4 parts of flame retardant, respectively, in parts by weight.

[0019] Furthermore, in step S2, the nucleating agent is ethylene-methacrylic acid copolymer; the flame retardant is a phosphorus-based flame retardant; and the antioxidant is antioxidant 1010.

[0020] Furthermore, in step S3, during melt extrusion, the temperature of the first zone of the screw extruder is 240-245°C, the temperature of the second zone is 250-255°C, the temperature of the third zone is 265-275°C, the temperature of the fourth zone is 285-295°C, and the temperature of the fifth zone is 275-280°C.

[0021] Furthermore, a high and low temperature resistant CPET composite material is prepared by the above method.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] In order to improve the high and low temperature resistance of CPET materials and enhance their impact resistance, the present invention modifies the toughening agent thereof during the preparation of CPET materials. The present invention first uses talc as a raw material. Talc is a type of layered silicate structure mineral, which contains a large amount of adsorbed water and organic matter. After calcining, the surface area of ​​talc can be effectively increased, and the interlayer spacing can be increased. Therefore, in the subsequent step, when KH570 is used to hydrolyze the surface of the talc, more double bonds can be introduced on the surface. On this basis, the present invention further uses 1,4-bis(dimethylsilyl)benzene containing silicon-hydrogen bonds as a raw material. In the presence of chloroplatinic acid catalyst, the silicon-hydrogen bonds in 1,4-bis(dimethylsilyl)benzene will react with the talc. The olefin double bonds on the surface of the stone powder undergo an addition reaction, thereby introducing a silicon-hydrogen structure on the surface of the talc powder. The talc powder with silicon-hydrogen bonds is then reacted with tetraethylene glycol dimethacrylate containing double bonds, thereby ultimately introducing a silane structure and an acrylate long carbon chain structure on the surface of the talc powder, effectively improving the dispersibility of the talc powder in PET. In addition, in order to improve the crystallization performance of CPET, the present invention also limits the particle size of the talc powder. After calcination, it is sieved through a 2500 mesh sieve to a particle size of less than 5 μm, so that the talc powder can act as a partial nucleating agent. The acrylate-based structure grafted on the surface of the talc powder can also improve the thermal stability of the material, thereby preventing thermal degradation during thermal processing and further improving the mechanical properties of the material after molding. DETAILED DESCRIPTION

[0024] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0025] The talc powder used in the examples and comparative examples of the present application is 3000 mesh talc powder; the PET resin used is RE5264 NC010 resin; the nucleating agent used is ethylene-methacrylic acid copolymer; the antioxidant used is antioxidant 1010; and the flame retardant used is aluminum hypophosphite;

[0026] Example 1. A method for preparing a high and low temperature resistant CPET composite material, comprising the following steps:

[0027] S1. Preparation of modified toughening agent;

[0028] S11 talc was placed in an air atmosphere, the calcination temperature was set to 850 ° C, the calcination time was 45min, after the calcination was completed, cooled to room temperature, ground and dispersed, after passing through a 2500 mesh sieve, the sieved powder was collected to obtain calcined talc;

[0029] S12. 5 parts by weight of calcined talc were dispersed in a 10 wt % sodium hydroxide solution, heated to 90-95°C, stirred for 8 h, and then centrifuged to separate the precipitate. The precipitate was washed with deionized water until neutral, and then vacuum dried to constant weight. The precipitate was then added to 40 parts of a 75 wt % ethanol aqueous solution, acetic acid was added to adjust the pH to 4-6.5, and then 1 part of KH570 was added. The temperature was raised to 85°C, stirred for 8 h, and then centrifuged to separate the precipitate. The precipitate was washed three times with anhydrous ethanol and then vacuum dried to constant weight to obtain silane-modified talc.

[0030] S13. Disperse 5 parts by weight of the silane-modified talc prepared in step S12 in tetrahydrofuran, disperse uniformly by ultrasonication, and then add the resulting mixture dropwise to 0.5 parts of 1,4-bis(dimethylsilyl)benzene. Stir continuously during the addition. Maintain the reaction solution at 55°C. After stirring under reflux for 4 hours, separate the precipitate by filtration, wash it three times with clean tetrahydrofuran, and vacuum dry it to constant weight to obtain silane-modified talc.

[0031] wherein 0.02 parts of chloroplatinic acid catalyst is additionally dispersed in the 1,4-bis(dimethylsilyl)benzene;

[0032] S14. 5 parts by weight of silane-modified talc were redispersed in tetrahydrofuran and ultrasonically dispersed uniformly. The resulting mixture was then added dropwise to 1 part of tetraethylene glycol dimethacrylate with constant stirring. The reaction system was maintained at 60°C and stirred under reflux in the dark for 8 hours. The precipitate was then centrifuged, washed three times with clean tetrahydrofuran, and dried to constant weight to obtain a modified toughening agent.

[0033] Wherein, 0.03 parts of chloroplatinic acid catalyst is additionally dispersed in the tetraethylene glycol dimethacrylate;

[0034] S2 by weight ratio, were weighed 90 parts of PET resin, 8 parts of modified toughening agent, 0.5 parts of nucleating agent, 0.5 parts of antioxidant, 1.5 parts of flame retardant, which were added to a high-speed mixer, mixed uniformly to obtain a mixture;

[0035] S3. The mixture was added to a twin-screw extruder and the temperatures in the first zone were set to 240°C, the second zone to 250°C, the third zone to 270°C, the fourth zone to 290°C, and the fifth zone to 280°C. The mixture was melt-extruded and pelletized to obtain a high- and low-temperature resistant CPET composite material.

[0036] Example 2. A method for preparing a high and low temperature resistant CPET composite material, comprising the following steps:

[0037] Compared with Example 1, this example increases the amount of modified toughening agent added in step S2, and the other steps remain unchanged;

[0038] S2. Weigh 90 parts of PET resin, 15 parts of modified toughening agent, 0.5 parts of nucleating agent, 0.5 parts of antioxidant, and 1.5 parts of flame retardant according to weight ratio, add them to a high-speed mixer, and mix thoroughly to obtain a mixture.

[0039] Example 3. A method for preparing a high and low temperature resistant CPET composite material, comprising the following steps:

[0040] Compared with Example 2, this example increases the calcination temperature in step S11, while the other steps remain unchanged;

[0041] S11. The talc powder was placed in an air atmosphere and calcined at 900°C for 45 minutes. After calcination, the mixture was cooled to room temperature, ground and dispersed, and passed through a 2500-mesh sieve. The sieved powder was collected to obtain calcined talc powder.

[0042] Example 4. A method for preparing a high and low temperature resistant CPET composite material, comprising the following steps:

[0043] Compared with Example 3, this embodiment increases the amount of KH570 added in step S12, and the other steps remain unchanged;

[0044] S12. Disperse 5 parts of calcined talc powder by weight into a 10 wt % sodium hydroxide solution, heat to 90-95°C, stir and react for 8 h, centrifuge and separate the precipitate, wash with deionized water until neutral, vacuum dry the precipitate to constant weight, add it to 40 parts of 75 wt % ethanol aqueous solution, add acetic acid to adjust the pH to 4-6.5, add 10 parts of KH570, heat to 85°C, stir and react for 8 h, centrifuge and separate the precipitate, wash the precipitate with anhydrous ethanol three times, and vacuum dry it to constant weight to obtain silane-modified talc powder.

[0045] Example 5. A method for preparing a high and low temperature resistant CPET composite material, comprising the following steps:

[0046] Compared with Example 4, this example increases the amount of 1,4-bis(dimethylsilyl)benzene added in step S13, and the other steps remain unchanged;

[0047] S13. Disperse 5 parts of the silane-modified talc prepared in step S12 in tetrahydrofuran by weight. After uniform dispersion by ultrasonic vibration, add the silane-modified talc dropwise to 5 parts of 1,4-bis(dimethylsilyl)benzene. Stir continuously during the addition process. Maintain the temperature of the reaction solution at 55°C. After reflux and stirring for 4 hours, filter and separate the precipitate. Wash it three times with clean tetrahydrofuran and vacuum dry it to constant weight to obtain silane-modified talc.

[0048] Example 6. A method for preparing a high and low temperature resistant CPET composite material, comprising the following steps:

[0049] Compared with Example 5, this example increases the amount of tetraethylene glycol dimethacrylate added in step S14, while the other steps remain unchanged;

[0050] S14. 5 parts by weight of silane-modified talc were redispersed in tetrahydrofuran and ultrasonically dispersed uniformly. The resulting mixture was then added dropwise to 10 parts of tetraethylene glycol dimethacrylate with constant stirring. The reaction system was maintained at 60°C and stirred under reflux in the dark for 8 hours. The precipitate was then centrifuged, washed three times with clean tetrahydrofuran, and dried to constant weight to obtain a modified toughening agent.

[0051] Wherein, 0.03 parts of chloroplatinic acid catalyst is additionally dispersed in the tetraethylene glycol dimethacrylate.

[0052] Comparative Example 1. A method for preparing a high and low temperature resistant CPET composite material, comprising the following steps:

[0053] Compared with Example 1, the talc powder was not calcined in this comparative example, but was only ground and sieved, and the other steps remained unchanged;

[0054] S11 The talc was ground and dispersed, after passing through a 2500 mesh sieve, the sieved powder was collected to obtain ground talc;

[0055] S12. Disperse 5 parts of ground talc powder by weight into a 10 wt % sodium hydroxide solution, heat to 90-95°C, stir and react for 8 h, centrifuge and separate the precipitate, wash with deionized water until neutral, vacuum dry the precipitate to constant weight, add it to 40 parts of 75 wt % ethanol aqueous solution, add acetic acid to adjust the pH to 4-6.5, add 1 part KH570, heat to 85°C, stir and react for 8 h, centrifuge and separate the precipitate, wash the precipitate with anhydrous ethanol three times, and vacuum dry it to constant weight to obtain silane-modified talc powder.

[0056] Comparative Example 2. A method for preparing a high and low temperature resistant CPET composite material, comprising the following steps:

[0057] Compared with Example 1, this comparative example only used ground and sieved talc as a toughening agent;

[0058] S1. Preparation of modified toughening agent;

[0059] Grind and disperse talc powder, pass it through a 2500-mesh sieve, and collect the sieved powder to obtain a modified toughening agent;

[0060] S2 by weight ratio, were weighed 90 parts of PET resin, 8 parts of modified toughening agent, 0.5 parts of nucleating agent, 0.5 parts of antioxidant, 1.5 parts of flame retardant, which were added to a high-speed mixer, mixed uniformly to obtain a mixture;

[0061] S3. The mixture was added to a twin-screw extruder and the temperatures in the first zone were set to 240°C, the second zone to 250°C, the third zone to 270°C, the fourth zone to 290°C, and the fifth zone to 280°C. The mixture was melt-extruded and pelletized to obtain a high- and low-temperature resistant CPET composite material.

[0062] Detection:

[0063] According to GB / T 1040.3-2006, the high and low temperature resistant CPET composite materials prepared in Examples 1 to 6 and Comparative Examples 1 to 2 were prepared as test specimens, and their tensile strength and elongation at break were tested at a rate of 50 mm / min.

[0064] According to GB / T 1843-2008, the high and low temperature resistant CPET composite materials prepared in Examples 1 to 6 and Comparative Examples 1 to 2 were prepared as test samples, and their notched Izod impact strength at 25°C and -30°C was measured.

[0065] The high and low temperature resistant CPET composite materials prepared in Examples 1 to 6 and Comparative Examples 1 to 2 were prepared into 250 mL bottles, which were steamed at 240° C. for 30 min, and their appearance changes were detected.

[0066] The test results are shown in the table below;

[0067]

[0068] As can be seen from the above table, in Example 2 of the present application, the amount of modified toughening agent added is increased compared to Example 1. After increasing its content, the talc powder with a smaller particle size acts as a partial nucleating agent, effectively improving the crystallization properties of the CPET material. The addition of the toughening agent effectively increases its tensile strength and impact strength. However, the addition of the inorganic toughening agent reduces its elongation at break and reduces its deformation under external force.

[0069] In Example 3, the calcination temperature was further increased, in which case the organic carbon was removed without causing a serious decrease in its porosity, and there was no significant decrease in the performance data; in Examples 4 to 6, the addition amount of each reactant in steps S12 to S14 was increased respectively, so that more active reaction groups could be grafted onto the surface of the talc powder, thereby increasing the silane and acrylate long carbon chain structures on the surface of the modified toughening agent finally synthesized. Compared with Comparative Examples 1 to 2, it can be seen that the silane and acrylate long carbon chain structures introduced on the surface of the talc powder effectively improve the compatibility and dispersibility between the talc powder and PET, improve the bonding strength between the toughening agent and the PET matrix, and improve its deformation resistance at high temperatures. In addition, the increase in the acrylate long carbon chain structure can effectively improve the impact performance of CPET in a low temperature environment, improve the conduction and dispersion of force after impact, and improve the mechanical properties of the material.

[0070] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing a high and low temperature resistant CPET composite material, characterized in that: The following steps are involved: S1. Preparation of modified toughening agent; S11 talc was placed in an air atmosphere, calcined, after calcination, cooled to room temperature, ground and dispersed, after passing through a 2500 mesh sieve, the sieved powder was collected to obtain calcined talc; S12. Calcined talc was dispersed in a sodium hydroxide solution, heated to 90-95°C, stirred for 4-8 hours, and then centrifuged to separate the precipitate. The solution was washed with deionized water until neutral, and then vacuum dried to constant weight. The solution was then added to an ethanol-water solution, and acetic acid was added to adjust the pH to 4-6.

5. KH570 was then added to the solution, and the solution was heated to 80-90°C, stirred for 4-8 hours, and then centrifuged to separate the precipitate. The precipitate was washed with anhydrous ethanol 2-3 times and then vacuum dried to constant weight to obtain silane-modified talc. S13. The silane-modified talc prepared in step S12 is dispersed in tetrahydrofuran, and after being uniformly dispersed by ultrasonic vibration, it is added dropwise to 1,4-bis(dimethylsilyl)benzene dispersed with chloroplatinic acid catalyst. Stirring is continued during the dropwise addition process. The temperature of the reaction solution is controlled to be maintained at 55-65°C. After stirring under reflux for 2-4 hours, the precipitate is separated by filtration, washed with clean tetrahydrofuran 2-3 times, and then vacuum dried to constant weight to obtain silane-modified talc. S14. Redisperse the silicon-hydrogen-modified talc in tetrahydrofuran (THF), ultrasonically disperse the powder until uniform, and then add it dropwise to tetraethylene glycol dimethacrylate (TETA) containing a chloroplatinic acid catalyst. Stir continuously during the addition. Maintain the reaction system at 60-66°C. Reflux and stir in the dark for 2-8 hours. Centrifuge the precipitate, wash it 2-3 times with clean THF, and dry it to constant weight to obtain a modified toughening agent. S2 by weight ratio, were weighed PET resin, modified toughening agent, nucleating agent, antioxidant, flame retardant, which were added to a high-speed mixer, mixed uniformly to obtain a mixture; Wherein, in step S2, the contents of each component are 85-90 parts of PET resin, 8-15 parts of modified toughening agent, 0.5-1 part of nucleating agent, 0.5-0.8 part of antioxidant, and 1.5-4 parts of flame retardant, respectively, in parts by weight; S3. The mixed material is added to a twin-screw extruder, melt-extruded and pelletized to obtain a high and low temperature resistant CPET composite material.

2. The method for preparing the high and low temperature resistant CPET composite material according to claim 1, wherein: In step S11, during calcination, the calcination temperature is 850-900° C. and the calcination time is 30-45 minutes.

3. The method for preparing the high and low temperature resistant CPET composite material according to claim 1, wherein: In step S12, the sodium hydroxide solution has a sodium hydroxide concentration of 10-30 wt%.

4. The method for preparing the high and low temperature resistant CPET composite material according to claim 1, wherein: In step S12, the mass ratio of the calcined talc powder, the ethanol aqueous solution, and KH570 is 5: (40-60): (1-10) in parts by weight; Wherein, the ethanol concentration in the ethanol aqueous solution is 60-75wt%.

5. The method for preparing the high and low temperature resistant CPET composite material according to claim 1, wherein: In step S13, the mass ratio of the silane-modified talc powder, the chloroplatinic acid catalyst, and 1,4-bis(dimethylsilyl)benzene is 5:(0.02-0.05):(0.5-5) in parts by weight.

6. The method for preparing the high and low temperature resistant CPET composite material according to claim 1, wherein: In step S14, the mass ratio of the silicon hydrogen modified talc powder, the chloroplatinic acid catalyst, and tetraethylene glycol dimethacrylate is 5: (0.03-0.05): (1-10) in parts by weight.

7. The method for preparing the high and low temperature resistant CPET composite material according to claim 1, wherein: In step S2 , the nucleating agent is ethylene-methacrylic acid copolymer; the flame retardant is a phosphorus-based flame retardant; and the antioxidant is antioxidant 1010.

8. The method for preparing the high and low temperature resistant CPET composite material according to claim 1, wherein: In step S3, during melt extrusion, the temperature of the first zone of the screw extruder is 240-245°C, the temperature of the second zone is 250-255°C, the temperature of the third zone is 265-275°C, the temperature of the fourth zone is 285-295°C, and the temperature of the fifth zone is 275-280°C.

9. A high and low temperature resistant CPET composite material prepared by the preparation method according to any one of claims 1 to 8.

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