High-barrier all-bio-based furan copolyamide film, preparation method and application thereof

Abstract

The application discloses a kind of high-barrier full-biobased furan copolyamide film and its preparation method and application, belong to film manufacturing technical field.The preparation method of the PA (XFX) 3Y film is as follows: after PA (XFX) 3Y resin chip is melted under certain temperature, pressure and time by hot press, four times of heat setting under specific time and pressure are carried out, three times of pressure break under specific time, and then the PA (XFX) 3Y film is obtained after natural cooling.The method for preparing PA (XFX) 3Y film is simple, the PA (XFX) 3Y film obtained presents amorphous structure characteristics, has very ideal gas barrier property, and is a sustainable material applied in food packaging field.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of thin film preparation, in particular to a high-barrier full-bio-based furan copolyamide film and a preparation method and application thereof. BACKGROUND

[0002] Plastics play an indispensable role in our daily life, but the large-scale production and consumption of plastics by humans have caused irreversible environmental damage and depletion of non-renewable fossil resources. Therefore, in order to reduce dependence on fossil resources and reduce carbon dioxide emissions, the use of bio-based polymers prepared from renewable biomass raw materials to replace petroleum-based polymers prepared from petroleum-based raw materials has become a major research focus in the academic and industrial communities. 2,5-furan dicarboxylic acid (FDCA) is the only aromatic compound among the 12 bio-based platform compounds selected by the US Department of Energy for production from sugars. FDCA is considered a good substitute for petroleum-based terephthalic acid (PTA) due to its structure and aromaticity similar to PTA. The development of FDCA-based polymers will meet the requirements of the "ban plastic" policy.

[0003] Among them, the related research of FDCA-based polyesters is relatively mature, especially poly(2,5-furan dicarboxylic acid ethylene glycol ester) (PEF) has attracted widespread attention from all walks of life because of its better gas barrier properties than poly(ethylene terephthalate) (PET) film, and its source of raw materials for packaging applications is more sustainable. As for polyamides, only MXD6 has good barrier properties at present, and the variety is single. Therefore, it is very important to develop polyamide varieties with high gas barrier properties, which are expected to become sustainable materials for food packaging applications. However, as for FDCA-based polyamides, there is no report on FDCA-based polyamides with excellent comprehensive performance, and there is no related research and report on the barrier properties of FDCA-based polyamides. Barrier properties are influenced by both crystalline and amorphous regions of the polymer, especially when compression molded, an ordered mesophase between crystalline and amorphous phases is formed, which can better inhibit gas transmission. However, the formation of mesophase is inhibited by the crystalline region.

[0004] The existing preparation of thin films usually adopts a biaxial stretching or a blown film method, but the above two methods have complex preparation steps, and the gas barrier properties of the prepared thin films need to be further improved; the gas barrier properties can also be improved by adding other substances such as silicon dioxide, but this way changes the original material composition. SUMMARY

[0005] To solve the problems in the prior art, the application provides a high-barrier full-bio-based furan copolyamide film and a preparation method and application thereof, and the gas barrier property of the full-bio-based furan copolyamide film is improved by controlling processing parameters such as temperature, pressure and time without changing the composition of PA(XFX)3Y, so that the full-bio-based furan copolyamide film has wide application in the field of food packaging materials.

[0006] To solve the above technical problems, the application provides the following technical solutions.

[0007] In one aspect, the application provides a preparation method of a high-barrier full-bio-based furan copolyamide film, comprising the following steps:

[0008] Step 1: slicing amorphous full-bio-based furan copolyamide PA(XFX)3Y resin, and then heating at a certain temperature; the temperature is between the glass transition temperature and the decomposition temperature of the amorphous full-bio-based furan copolyamide PA(XFX)3Y resin.

[0009] Step 2: performing first heat setting, the heat setting pressure is 15-20 MPa, and the time is 10 min; then releasing pressure to normal pressure and keeping for 3 min;

[0010] Step 3: performing second heat setting, the heat setting pressure is 30-40 MPa, and the time is 10 min; then releasing pressure to normal pressure and keeping for 3 min;

[0011] Step 4: performing third heat setting, the heat setting pressure is 60-80 MPa, and the time is 5 min; then releasing pressure to normal pressure and keeping for 3 min;

[0012] Step 5: performing fourth heat setting, the heat setting pressure is 90-100 MPa, and the time is 5 min; then releasing pressure to normal pressure and keeping for 3 min;

[0013] Step 6: obtaining the full-bio-based furan copolyamide film after natural cooling.

[0014] Further, the glass transition temperature of the amorphous full-bio-based furan copolyamide PA(XFX)3Y resin is greater than or equal to 60 DEG C, and the decomposition temperature is greater than or equal to 380 DEG C; the preparation method of the amorphous full-bio-based furan copolyamide PA(XFX)3Y resin is as follows:

[0015] (1) preparing amino-terminated nylon active segments by amide ester exchange of 2,5-furan dimethyl acid and diamine X, as monomers for subsequent polymerization; the molar ratio of 2,5-furan dimethyl acid and diamine X is 3:4-3:4.2

[0016] (2) The amino-terminated active nylon segment obtained in (1) is dissolved in a polar solvent and titrated with a certain concentration of dilute hydrochloric acid solution to obtain the actual molecular weight of the nylon active segment;

[0017] (3) Equal moles of amino-terminated nylon active segment and dibasic acid Y, as well as a catalyst, a stabilizer, an antioxidant, and an appropriate amount of water are added to a high-temperature and high-pressure reaction kettle, and then a bio-based furan copolyamide with regular segments, high molecular weight, high transparency, and high strength and toughness is obtained by melt polycondensation.

[0018] Preferably, in step (1), the diamine is pentanediamine or decanediamine; the dibasic acid is glutaric acid or sebacic acid; in step (2), the polar solvent is hexafluoroisopropanol or trifluoroethanol; the dilute hydrochloric acid concentration is 0.05-0.1 mol / L; in step (3), the catalyst is one or more of sodium hypophosphite, titanium isopropoxide, titanium citrate, triphenyl phosphite, and 1,5,7-triazabicyclo[4.4.0]dec-5-ene; the antioxidant is antioxidant 1010 or antioxidant 1098; and the stabilizer is stabilizer SEED.

[0019] The molar ratio of dimethyl 2,5-furan dicarboxylate to diamine X is 3:4-3:4.2; and the specific structure of the amorphous full-bio-based furan copolyamide PA(XFX)3Y resin is as follows:

[0020] ;

[0021] wherein X is a linear aliphatic diamine, which is pentanediamine or decanediamine; and Y is a bio-based dibasic acid, which is glutaric acid or sebacic acid.

[0022] Further, step (1) specifically comprises: dimethyl 2,5-furan dicarboxylate and a slight excess of diamine X are added to a glass kettle equipped with mechanical stirring and condensing devices, and under nitrogen flow, i.e. under normal pressure, the temperature is raised to 120 ℃ and reacted for 2 h, during which a large amount of methanol is generated; then the temperature is raised to 160-190 ℃ and reacted for 1-2 h, after which the temperature is raised to 210 ℃ and reacted for 0.5 h, during which only a small amount of methanol is generated; finally, vacuum reaction is performed at -0.07 MPa for 15 min to remove residual small molecules, thereby obtaining the amino-terminated active nylon segment.

[0023] Preferably, in step (2), the polar solvent is one of hexafluoroisopropanol and trifluoroethanol, and the dilute hydrochloric acid concentration is 0.05-0.1 mol / L.

[0024] Further, the step (2) is specifically: 0.2-0.4 g of nylon active segment is placed in a 100 mL beaker, 30-50 mL of polar solvent is added, stirred for 0.5-2 h for dissolution, then placed on an automatic potentiometric titrator, and titrated with a certain concentration of dilute hydrochloric acid solution while stirring to obtain the actual molecular weight of the nylon active segment.

[0025] Preferably, in the step (3), the catalyst is used in an amount of 2 ‰ of the total mass of the nylon active segment and the dibasic acid; the antioxidant is used in an amount of 1 ‰ of the total mass of the nylon active segment and the dibasic acid; and the stabilizer is used in an amount of 1 ‰ of the total mass of the nylon active segment and the dibasic acid.

[0026] Further, in the step (3), the preparation of the bio-based furan copolyamide is specifically: the actual molecular weight of the nylon active segment titrated in the step (2) is used to calculate the molar number thereof. Then, an equal molar amount of the nylon active segment, the dibasic acid Y, the catalyst, the stabilizer, the antioxidant, and an appropriate amount of water are added to a high-temperature and high-pressure reaction kettle, air is replaced by nitrogen, then the temperature is raised to 5-10 ℃ above the melting point of the dibasic acid Y and stabilized for 0.5-2 h, then reacted at 190-220 ℃ for 2 h, then slowly releases small molecules in the system at 220-230 ℃, then reacted at 230 ℃ and 0 MPa for 1-2 h, and finally reacted at 240-250 ℃ and -0.09 MPa for 1-2 h to complete the polymerization. The system is returned to normal pressure, the reaction kettle is opened, and the bio-based furan copolyamide is quickly taken out and placed in deionized water, and then the bio-based furan copolyamide product is placed in a 60 ℃ air-drying oven and dried for 24 h.

[0027] On the other hand, the application also provides a high-barrier full-bio-based furan copolyamide film prepared by the above method.

[0028] In another aspect, the application also provides an application of the above high-barrier full-bio-based furan copolyamide film in food packaging materials, which can be used in food packaging film bags, food packaging boxes, or food packaging bottles. The gas barrier property of the prepared full-bio-based furan copolyamide film is better than that of PEF, PET, or even MXD6.

[0029] Compared with the prior art, the application has the following beneficial effects:

[0030] The full-bio-based furan copolyamide PA(XFX)3Y film prepared by the application has amorphous structure characteristics and very excellent gas barrier property, and can be applied in the field of food packaging materials, including food packaging film bags, food packaging boxes, and food packaging bottles.

[0031] The method of the present application can make the prepared full-bio-based furan copolyamide PA(XFX)3Y film have excellent gas barrier property without changing the composition of the full-bio-based furan copolyamide PA(XFX)3Y resin, by controlling the processing process such as temperature, pressure and time. Different from the conventional compression molding process, by gradually pressurizing for a certain time and depressurizing for a certain time, the disordered hydrogen bonds in the PA(XFX)3Y can be rearranged, and the interaction between the molecular chains can be enhanced, forming an ordered intermediate phase between the amorphous phase and the crystalline phase. At the same time, by this way of cyclic pressurization and depressurization, the arrangement of this ordered intermediate phase can be maximized, thereby more effectively hindering the passage of gas. In addition, the maximization of the arrangement of the ordered intermediate phase can increase the glass transition temperature of the full-bio-based furan copolyamide PA(XFX)3Y film, so that it is in a glass state as soon as possible, the free volume is frozen, and remains at a minimum value, there is not enough space for the molecular chain to move, and also makes it difficult for gas molecules to diffuse. After four cycles of pressurization and depressurization, a high-barrier full-bio-based furan copolyamide PA(XFX)3Y film is finally obtained.

[0032] Compared with the prior art, the present application provides a preparation method of a high-barrier full-bio-based furan copolyamide film, which has very excellent gas barrier property by using a simple processing process, which is better than PET, PEF, and even MXD6. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 DSC curves of PA(5F5)35 before and after cyclic compression molding in Example 1;

[0034] Figure 2 XRD spectra of PA(5F5)35 before and after cyclic compression molding in Example 1. DETAILED DESCRIPTION

[0035] In order to make the technical problems, technical solutions and advantages of the present application clearer, specific embodiments will be described in detail below with reference to the accompanying drawings.

[0036] In the present application, the materials and reagents used are commercially available if not otherwise specified.

[0037] The present application provides a high-barrier full-bio-based furan copolyamide film, a preparation method and application thereof, and the specific embodiments are as follows.

[0038] Example 1

[0039] A preparation method of a high-barrier full-bio-based furan copolyamide film, comprising:

[0040] Step 1: 30 g of PA(5F5)35 resin chips were melted at 255 °C for 30 min under normal pressure;

[0041] Step 2: the first heat setting temperature was 255 °C, the pressure was 15 MPa, and the time was 10 min; then the pressure was released to normal pressure and maintained for 3 min;

[0042] Step 3: the second heat setting temperature was 255 °C, the pressure was 30 MPa, and the time was 10 min; then the pressure was released to normal pressure and maintained for 3 min;

[0043] Step 4: the third heat setting temperature was 255 °C, the pressure was 60 MPa, and the time was 5 min; then the pressure was released to normal pressure and maintained for 3 min;

[0044] Step 5: the fourth heat setting temperature was 255 °C, the pressure was 90 MPa, and the time was 5 min; then the pressure was released to normal pressure;

[0045] Step 6: after natural cooling, a full-bio-based furan copolyamide film was obtained.

[0046] The PA(5F5)35 resin described above was prepared by the following method:

[0047] (1) 184.15 parts of dimethyl 2,5-furan dicarboxylate and 143.05 parts of pentanediamine were added to a glass kettle with a magnetic stirring device and a condensing device, and the molar ratio of the dimethyl 2,5-furan dicarboxylate and the pentanediamine was 3:4.2; under the flow of nitrogen, i.e. normal pressure, the temperature was raised to 120 °C and reacted for 2 h, at this stage a large amount of methanol was generated, then the temperature was raised to 190 °C and reacted for 2 h, then the temperature was raised to 210 °C and reacted for 0.5 h, at these three temperature stages only a small amount of methanol was generated, finally vacuum reaction was carried out at -0.07 MPa for 15 min to remove the residual small molecules, thereby obtaining an amino-terminated active nylon segment (5F5)3;

[0048] (2) 0.3 parts of (5F5)3 was dissolved in 30 mL of hexafluoroisopropanol, stirred to dissolve, and titrated by an automatic potentiometric titrator using 0.05 mol / L of dilute hydrochloric acid solution, thereby obtaining the actual average molecular weight of (5F5)3 diamine as 780 g / mol;

[0049] (3) 100 parts of (5F5)3 and 16.94 parts of glutaric acid and 0.234 parts of catalyst sodium hypophosphite, 0.117 parts of antioxidant 1010, 0.117 parts of stabilizer SEED and 5.847 parts of deionized water were added into a high temperature and high pressure reactor, wherein the molar ratio of (5F5)3 and glutaric acid was 1:1; first, the air was replaced by nitrogen, then heated to 5-10 ℃ above the melting point of adipic acid, that is, 160 ℃, and stabilized for 1 h, then reacted at 230 ℃ for 2 h, then slowly released the small molecules in the system at 230 ℃; then reacted at 240 ℃, 0 MPa for 1 h, and finally reacted at 250 ℃, -0.09 MPa for 1 h to complete the polymerization. The system was restored to normal pressure, the reactor was opened, and the bio-based furan copolyamide was quickly taken out and placed in deionized water, and then the bio-based furan copolyamide product was placed in a 60 ℃ air drying oven for drying for 24 h.

[0050] Example 2

[0051] A preparation method of a high-barrier full-bio-based furan copolyamide film, comprising:

[0052] Step 1: 30 g of PA(5F5)310 resin chips were melted at a temperature of 245 ℃ for 25 min under normal pressure;

[0053] Step 2: The process conditions were the same as those in Example 1, except that the temperature for four heat setting was 245 ℃.

[0054] The above-mentioned PA(5F5)310 resin was prepared by the following method:

[0055] (1)-(2) The preparation method was the same as that in Example 1, and the molecular weight of (5F5)3 diamine was 780 g / mol;

[0056] (3) 100 parts of (5F5)3 diamine and 25.93 parts of sebacic acid and 0.252 parts of catalyst triphenyl phosphite, 0.126 parts of antioxidant 1098, 0.126 parts of stabilizer SEED and 6.30 parts of deionized water were added into a high temperature and high pressure reactor, then heated to 5-10 ℃ above the melting point of sebacic acid, that is, 140 ℃, and stabilized for 1 h, then reacted at 220 ℃ for 2 h, then slowly released the small molecules in the system at 220 ℃; then reacted at 230 ℃, 0 MPa for 1 h, and finally reacted at 240 ℃, -0.09 MPa for 1 h to complete the polymerization. The system was restored to normal pressure, the reactor was opened, and the bio-based furan copolyamide was quickly taken out and placed in deionized water, and then the bio-based furan copolyamide product was placed in a 60 ℃ air drying oven for drying for 24 h.

[0057] Example 3

[0058] A preparation method of a high-barrier full-bio-based furan copolyamide film, comprising:

[0059] Step 1: 30 g of PA(10F10)35 resin chips were melted at a temperature of 240 ℃ under normal pressure for 20 min;

[0060] Step 2: The process conditions were the same as those in Example 1, except that the temperature for four heat setting was 240 ℃.

[0061] The PA(10F10)35 resin was prepared by the following method:

[0062] (1) 184.15 parts of dimethyl 2,5-furan dicarboxylate and 241.23 parts of decanediamine were added to a glass kettle with a magnetic stirring device and a condensing device, and reacted at 140 ℃ for 2 h under nitrogen flow (normal pressure), at which stage a large amount of methanol was generated, then reacted at 200 ℃ for 2 h, and then reacted at 220 ℃ for 0.5 h, at which stage only a small amount of methanol was generated, and finally vacuum reacted at -0.07 MPa for 15 min to remove the residual small molecules, thereby obtaining an active nylon segment (10F10 (3) diamine) with three repeating units capped with amino groups.

[0063] (2) 0.3 parts of 10F10 (3) diamine was dissolved in 30 mL of hexafluoroisopropanol, stirred until dissolved, and titrated by using a 0.05 mol / L dilute hydrochloric acid solution through an automatic potentiometric titrator, to obtain the actual average molecular weight of 10F10 (3) diamine of 1034 g / mol

[0064] (3) 100 parts of 10F10 (3) diamine, 12.78 parts of glutaric acid, 0.226 parts of catalyst titanium citrate, 0.113 parts of antioxidant 1098, 0.113 parts of stabilizer SEED, and 5.64 parts of deionized water were added to a high-temperature and high-pressure reaction kettle, first replaced with nitrogen, then heated to 5-10 ℃ above the melting point of adipic acid, i.e. 160 ℃, and stabilized for 1 h, then reacted at 220 ℃ for 2 h, then slowly released the small molecules in the system at 220 ℃; then reacted at 230 ℃ and 0 MPa for 1 h, and finally reacted at 240 ℃ and -0.09 MPa for 1 h to complete the polymerization. The system was returned to normal pressure, the reaction kettle was opened, and the full-bio-based furan copolyamide was quickly taken out and placed in deionized water, and then the full-bio-based furan copolyamide product was placed in a 60 ℃ air-drying oven for drying for 24 h.

[0065] Example 4

[0066] A preparation method of a high-barrier full-bio-based furan copolyamide film, comprising:

[0067] Step 1: 30 g of PA(10F10)310 resin chips are melted at a temperature of 230 ℃ under normal pressure for 15 min;

[0068] Step 2: The process conditions are the same as those in Example 1, except that the temperature for the fourth heat setting is 230 ℃.

[0069] The PA(10F10)310 resin is prepared by the following method:

[0070] (1) The same as in Example 3, to obtain 10F10 (3) The molecular weight of the diamine is 1034 g / mol;

[0071] (3) 100 parts of 10F10 (3) The diamine, 19.56 parts of sebacic acid, 0.240 parts of catalyst 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 0.120 parts of antioxidant 1010, 0.120 parts of stabilizer SEED, and 5.98 parts of deionized water are added to a high-temperature and high-pressure reaction kettle, and the air is replaced by nitrogen gas first, and then the temperature is raised to 5-10 ℃ above the melting point of adipic acid, that is, 160 ℃, and stabilized for 1 h, and then reacted at 220 ℃ for 2 h, and then slowly released the small molecules in the system at 220 ℃; then reacted at 230 ℃, 0 MPa for 1 h, and finally reacted at 240 ℃, -0.09 MPa for 1 h, to complete the polymerization. The system is restored to normal pressure, the reaction kettle is opened, and the bio-based furan copolyamide is quickly taken out and placed in deionized water, and then the bio-based furan copolyamide product is placed in a 60 ℃ air-drying oven for drying for 24 h.

[0072] Example 5

[0073] A preparation method of a high-barrier full-bio-based furan copolyamide, comprising:

[0074] (1) 30 g of PA(5F5)35 resin chips are melted at a temperature of 255 ℃ for 30 min;

[0075] (2) The temperature for the first heat setting is 255 ℃, the pressure is 20 MPa, and the time is 10 min; the time for the first pressure relief is 3 min, and the pressure is normal pressure.

[0076] (3) The temperature for the second heat setting is 255 ℃, the pressure is 40 MPa, and the time is 10 min; the time for the second pressure relief is 3 min, and the pressure is normal pressure.

[0077] (4) the third heat setting temperature is 255 DEG C, the pressure is 80 MPa, and the time is 5 min; the third pressure break time is 3 min, and the pressure is normal pressure.

[0078] (5) the fourth heat setting temperature is 255 DEG C, the pressure is 100 MPa, and the time is 5 min;

[0079] (6) after natural cooling, the full bio-based furan copolyamide film is obtained.

[0080] The PA(5F5)35 resin preparation method is the same as that in Example 1.

[0081] To further illustrate the beneficial effects of the present application, a comparative example is constructed as follows

[0082] Comparative Example 1

[0083] A film preparation method comprises the following steps:

[0084] Step 1: 30 g of PA(5F5)35 resin chips are melted at a temperature of 255 DEG C for 30 min;

[0085] Step 2: the heat setting temperature is 255 DEG C, the pressure is 90 MPa, and the time is 10 min;

[0086] Step 3: after natural cooling, the full bio-based furan copolyamide film is obtained.

[0087] The PA(5F5)35 resin preparation method is the same as that in Example 1.

[0088] Comparative Example 2

[0089] A film preparation method comprises the following steps:

[0090] Step 1: 30 g of PA(5F5)310 resin chips are melted at a temperature of 245 DEG C for 25 min;

[0091] Step 2: the heat setting temperature is 245 DEG C, the pressure is 90 MPa, and the time is 10 min;

[0092] Step 3: after natural cooling, the full bio-based furan copolyamide film is obtained.

[0093] The PA(5F5)310 resin preparation method is the same as that in Example 2.

[0094] Comparative Example 3

[0095] A film preparation method comprises the following steps:

[0096] Step 1: 30 g of PA(10F10)35 resin chips are melted at a temperature of 240 DEG C for 20 min;

[0097] Step 2: heat setting temperature is 245 °C, pressure is 90 MPa, time is 10 min;

[0098] Step 3: after natural cooling, a full-bio-based furan copolyamide film is obtained.

[0099] The PA(10F10)35 resin preparation method is the same as that in Example 3.

[0100] Comparative Example 4

[0101] A method for preparing a film, comprising:

[0102] Step 1: 30 g of PA(10F10)310 resin chips are melted at a temperature of 230 °C for 15 min;

[0103] Step 2: heat setting temperature is 245 °C, pressure is 90 MPa, time is 10 min;

[0104] Step 3: after natural cooling, a full-bio-based furan copolyamide film is obtained.

[0105] The PA(10F10)310 resin preparation method is the same as that in Example 4.

[0106] Comparative Example 5

[0107] A method for preparing a film, comprising:

[0108] Step 1: 30 g of PA(5F5)35 resin chips are melted at a temperature of 255 °C for 30 min;

[0109] Step 2: first heat setting temperature is 255 °C, pressure is 15 MPa, time is 10 min;

[0110] Step 3: second heat setting temperature is 255 °C, pressure is 30 MPa, time is 10 min;

[0111] Step 4: third heat setting temperature is 255 °C, pressure is 60 MPa, time is 5 min;

[0112] Step 5: fourth heat setting temperature is 255 °C, pressure is 90 MPa, time is 5 min;

[0113] Step 6: after natural cooling, a full-bio-based furan copolyamide film is obtained.

[0114] The PA(5F5)35 resin preparation method is the same as that in Example 1.

[0115] Comparative Example 6

[0116] A method for preparing a film, comprising:

[0117] Step 1: 30 g PA(5F5)310 resin chips were melted at a temperature of 245 °C for 25 min;

[0118] Step 2: the first heat setting temperature was 245 °C, the pressure was 15 MPa, and the time was 10 min;

[0119] Step 3: the second heat setting temperature was 245 °C, the pressure was 30 MPa, and the time was 10 min;

[0120] Step 4: the third heat setting temperature was 245 °C, the pressure was 60 MPa, and the time was 5 min;

[0121] Step 5: the fourth heat setting temperature was 245 °C, the pressure was 90 MPa, and the time was 5 min;

[0122] Step 6: after natural cooling, a full-bio-based furan copolyamide film was obtained.

[0123] The above PA(5F5)310 resin preparation method is the same as Example 2.

[0124] Comparative Example 7

[0125] A method for preparing a film, comprising:

[0126] Step 1: 30 g PA(10F10)35 resin chips were melted at a temperature of 240 °C for 20 min;

[0127] Step 2: the first heat setting temperature was 240 °C, the pressure was 15 MPa, and the time was 10 min;

[0128] Step 3: the second heat setting temperature was 240 °C, the pressure was 30 MPa, and the time was 10 min;

[0129] Step 4: the third heat setting temperature was 240 °C, the pressure was 60 MPa, and the time was 5 min;

[0130] Step 5: the fourth heat setting temperature was 240 °C, the pressure was 90 MPa, and the time was 5 min;

[0131] Step 6: after natural cooling, a full-bio-based furan copolyamide film was obtained.

[0132] The above PA(10F10)35 resin preparation method is the same as Example 3.

[0133] Comparative Example 8

[0134] A method for preparing a film, comprising:

[0135] Step 1: 30 g PA(10F10)310 resin chips were melted at a temperature of 230 ℃ for 15 min;

[0136] Step 2: the first heat setting temperature was 230 ℃, the pressure was 15 MPa, and the time was 10 min;

[0137] Step 3: the second heat setting temperature was 230 ℃, the pressure was 30 MPa, and the time was 10 min;

[0138] Step 4: the third heat setting temperature was 230 ℃, the pressure was 60 MPa, and the time was 5 min;

[0139] Step 5: the fourth heat setting temperature was 230 ℃, the pressure was 90 MPa, and the time was 5 min;

[0140] Step 6: after natural cooling, a full-bio-based furan copolyamide film was obtained.

[0141] The above PA(10F10)310 resin preparation method is the same as Example 4.

[0142] Comparative Example 9

[0143] A method for preparing a film, comprising:

[0144] (1) 30 g PET resin chips were melted at a temperature of 270 ℃ for 30 min;

[0145] (2) the first heat setting temperature was 270 ℃, the pressure was 15 MPa, and the time was 10 min; the first pressure break time was 3 min;

[0146] (3) the second heat setting temperature was 270 ℃, the pressure was 30 MPa, and the time was 10 min; the second pressure break time was 3 min;

[0147] (4) the third heat setting temperature was 270 ℃, the pressure was 60 MPa, and the time was 5 min; the third pressure break time was 3 min;

[0148] (5) the fourth heat setting temperature was 270 ℃, the pressure was 90 MPa, and the time was 5 min;

[0149] (6) after natural cooling, a PET film was obtained.

[0150] Comparative Example 10

[0151] (1) 30 g PEF resin chips were melted at a temperature of 245 ℃ for 30 min;

[0152] (2) the first heat setting temperature is 245 °C, the pressure is 15 MPa, and the time is 10 min; the first pressure break time is 3 min;

[0153] (3) the second heat setting temperature is 245 °C, the pressure is 30 MPa, and the time is 10 min; the second pressure break time is 3 min;

[0154] (4) the third heat setting temperature is 245 °C, the pressure is 60 MPa, and the time is 5 min; the third pressure break time is 3 min;

[0155] (5) the fourth heat setting temperature is 245 °C, the pressure is 90 MPa, and the time is 5 min;

[0156] (6) the PEF film is obtained after natural cooling.

[0157] Comparative Example 11

[0158] A method for preparing a film, comprising:

[0159] (1) 30 g MXD6 resin chips are melted at a temperature of 260 °C for 30 min;

[0160] (2) the first heat setting temperature is 260 °C, the pressure is 15 MPa, and the time is 10 min; the first pressure break time is 3 min;

[0161] (3) the second heat setting temperature is 260 °C, the pressure is 30 MPa, and the time is 10 min; the second pressure break time is 3 min;

[0162] (4) the third heat setting temperature is 260 °C, the pressure is 60 MPa, and the time is 5 min; the third pressure break time is 3 min;

[0163] (5) the fourth heat setting temperature is 260 °C, the pressure is 90 MPa, and the time is 5 min;

[0164] (6) the MXD6 film is obtained after natural cooling.

[0165] Comparative Example 12

[0166] In this comparative example, the first heat setting pressure is 10 MPa, and the rest of the conditions are the same as in Example 1.

[0167] Comparative Example 13

[0168] In this comparative example, the first heat setting pressure is 25 MPa, and the rest of the conditions are the same as in Example 1.

[0169] Comparative Example 14

[0170] In this comparative example, the second heat setting pressure was 50 MPa, and the rest of the conditions were the same as in Example 1.

[0171] Comparative Example 15

[0172] In this comparative example, the second heat setting pressure was 25 MPa, and the rest of the conditions were the same as in Example 1.

[0173] Comparative Example 16

[0174] In this comparative example, the third heat setting pressure was 90 MPa, and the rest of the conditions were the same as in Example 1.

[0175] Comparative Example 17

[0176] In this comparative example, the third heat setting pressure was 50 MPa, and the rest of the conditions were the same as in Example 1.

[0177] Comparative Example 18

[0178] In this comparative example, the fourth heat setting pressure was 110 MPa, and the rest of the conditions were the same as in Example 1.

[0179] Comparative Example 19

[0180] In this comparative example, the fourth heat setting pressure was 85 MPa, and the rest of the conditions were the same as in Example 1.

[0181] The films prepared in the examples and comparative examples were tested for barrier properties using a VAC-V2 pressure differential method gas permeation instrument. The sample diameter was 13 mm for CO2and 75 mm for O2, and the thickness was 1 mm. The test temperature was 23℃±2℃, and the humidity was 49±1%RH. 1 barrer = 10 –10 cm 3 ·cm / cm 2 ·s·cmHg. The specific test results are shown in Tables 1-3.

[0182] The glass transition temperature of the PA(XFX)3Y resin and the film prepared by compression was measured by differential scanning calorimetry (DSC), and the results are shown in Figure 1 and Tables 1-3. The XRD of the PA(XFX)3Y resin and the film prepared by compression was measured, and the results are shown in Figure 2 and Tables 1-3.

[0183] Table 1

[0184]

[0185] From Figures 1-2and the data in Table 1, the intermolecular interaction force of the film prepared by the method of the present application is stronger than that of the PA(XFX)3Y resin before compression, the glass transition temperature is increased by about 10 ℃, the disordered hydrogen bonds between the PA(XFX)3Y molecular chains are rearranged, the arrangement of the formed ordered intermediate phase is maximized, the gas barrier property is very excellent, and the oxygen gas barrier property is as low as 0.0003 x 10 –10 cm 3 ·cm / cm 2 ·s·cmHg, the carbon dioxide gas barrier property is 0.0015 x 10 –10 cm 3 ·cm / cm 2 ·s·cmHg.

[0186] Table 2

[0187]

[0188] As can be seen from Tables 1-2, Comparative Examples 1-5 and Comparative Examples 1-4, if the full-bio-based furan copolyamide PA(XFX)3Y film is prepared by the conventional compression molding method without stepwise cyclic pressurization and pressure interruption, the oxygen and carbon dioxide gas permeation coefficients will be relatively poor. This is because the disordered hydrogen bonds between the amorphous PA(XFX)3Y molecular chains cannot be fully arranged, the intermolecular interaction force is relatively small, and the glass transition temperature is only increased by 1-2 ℃.

[0189] As can be seen from Comparative Examples 1-5 and Comparative Examples 5-8, if the full-bio-based furan copolyamide PA(XFX)3Y film is prepared only by stepwise pressurization without pressure interruption, the oxygen and carbon dioxide gas permeation coefficients will be relatively poor. This is because stepwise pressurization can rearrange the disordered hydrogen bonds between the amorphous PA(XFX)3Y molecular chains, relatively enhance the intermolecular interaction force, and increase the glass transition temperature by 4-6 ℃, but the arrangement of the formed ordered intermediate phase cannot be maximized.

[0190] As can be seen from Comparative Examples 1-5 and Comparative Examples 9-11, the full-bio-based furan copolyamide PA(XFX)3Y film prepared by the stepwise cyclic pressurization and pressure interruption method has a gas barrier property one order of magnitude higher than that of the PET film, PEF film or even MXD6 film prepared by the same method.

[0191] Table 3

[0192]

[0193] From Table 3, it can be found that, comparing Example 1 and Comparative Examples 12-19, as long as one step does not reach the specified pressure, the gas barrier property of the obtained full-bio-based furan copolyamide PA(XFX) 3Y film is not as good as that of the full-bio-based furan copolyamide PA(XFX) 3Y film obtained by the method of cyclic pressurization and pressure break under specific pressure and specific time, but is better than that of the full-bio-based furan copolyamide PA(XFX) 3Y film obtained by conventional compression molding.

[0194] The pressure of the first heat setting is too small (Comparative Example 12) or too large (Comparative Example 13), and the glass transition temperature of the obtained film is not much different from that of the resin material, and the barrier property of the prepared film is also poor. This may be due to the fact that when the pressure is too small, the molecular chains cannot be fully arranged and air bubbles cannot be well removed; when the pressure is too large, it may cause overflow and waste of resources and incomplete film preparation with wrinkles. When the pressure of the subsequent three heat settings is too large or too small (Comparative Examples 14-19), the gas barrier property of the prepared film is different, but is far lower than that of the film prepared in Example 1 of the present application.

[0195] In summary, the present application designs an amorphous full-bio-based furan copolyamide PA(XFX) 3Y, which has excellent gas barrier property. At the same time, without changing the composition of the full-bio-based furan copolyamide PA(XFX) 3Y resin, by controlling the processing parameters such as temperature, pressure and time, and using step-by-step cyclic pressurization and pressure break, the full-bio-based furan copolyamide PA(XFX) 3Y film prepared has more excellent gas barrier property, and can be applied in the field of food packaging materials, including food packaging film bags, food packaging boxes, and food packaging bottles.

[0196] The above describes the preferred embodiments of the present application, and for those skilled in the art, without departing from the principles of the present application, some improvements and refinements should also be considered within the protection scope of the present application.

Claims

1. A method for preparing a high-barrier all-bio-based furan copolyamide film, characterized in that: include: Step 1: Slicing an amorphous all-bio-based furan copolyamide PA (XFX) 3Y resin, and then heating it at a certain temperature; the temperature is between the glass transition temperature and the decomposition temperature of the amorphous all-bio-based furan copolyamide PA (XFX) 3Y resin; Step 2: Perform the first heat setting at a pressure of 15-20 MPa for 10 minutes; then release the pressure to normal pressure and maintain for 3 minutes; Step 3: Perform a second heat-setting process at a pressure of 30-40 MPa for 10 minutes; then release the pressure to normal pressure and maintain for 3 minutes; Step 4: Perform a third heat-setting process at a pressure of 60-80 MPa for 5 minutes; then release the pressure to normal pressure and maintain for 3 minutes; Step 5: Perform the fourth heat-setting process at a pressure of 90-100 MPa for 5 minutes; then release the pressure to normal pressure and maintain for 3 minutes; Step 6: After natural cooling, a fully bio-based furan copolyamide film is obtained; The amorphous all-bio-based furan copolyamide PA (XFX) 3Y resin has a glass transition temperature of ≥60°C and a decomposition temperature of ≥380°C; wherein X is pentamethylenediamine or decanediamine; and Y is glutaric acid or sebacic acid. The preparation method of the amorphous all-bio-based furan copolyamide PA (XFX) 3Y resin is as follows: (1) Under nitrogen protection, dimethyl 2,5-furandicarboxylate and diamine are added to a glass kettle, and the temperature is raised several times to react to obtain an amino-terminated active nylon segment; the molar ratio of dimethyl 2,5-furandicarboxylate to diamine is 3:4-3:4.2; (2) dissolving the active nylon chain segment obtained in step (1) in a polar solvent, and then titrating the molecular weight with a dilute hydrochloric acid solution to obtain the actual molecular weight of the nylon active chain segment; (3) adding the active nylon segment and dibasic acid obtained in step (1) together with a catalyst, an antioxidant, a stabilizer and an appropriate amount of water into a high-temperature and high-pressure reactor, replacing the air with nitrogen, and then obtaining an amorphous all-biobased furan copolyamide by melt polycondensation; The molar ratio of the active nylon segment to the dibasic acid is 1:

1.

2. The preparation method according to claim 1, characterized in that In the step (1), the diamine is pentamethylenediamine or decanediamine; the dibasic acid is glutaric acid or sebacic acid; in the step (2), the polar solvent is hexafluoroisopropanol or trifluoroethanol; the concentration of the dilute hydrochloric acid solution is 0.05-0.1 mol / L; in the step (3), the catalyst is one or more of sodium hypophosphite, titanium isopropoxide, titanium citrate, triphenyl phosphite and 1,5,7-triazabicyclo[4.4.0]dec-5-ene; the antioxidant is antioxidant 1010 or antioxidant 1098; and the stabilizer is stabilizer SEED.

3. The preparation method according to claim 2, characterized in that The step (1) is specifically as follows: dimethyl 2,5-furandicarboxylate and diamine are added to a glass kettle equipped with a mechanical stirrer and condenser in a defined molar ratio, and the temperature is raised to 120°C under nitrogen flow at normal pressure for reaction for 2 h, then the temperature is raised to 160-190°C for reaction for 1-2 h, then the temperature is raised to 210°C for reaction for 0.5 h, and finally the temperature is vacuum reacted at -0.07 MPa for 15 min, thereby obtaining an amino-terminated active nylon segment.

4. The preparation method according to claim 3, characterized in that The step (2) is specifically as follows: 0.2-0.4 g of the nylon active chain segment is placed in a 100 mL beaker, 30-50 mL of a polar solvent is added and stirred for 0.5-2 h to dissolve, and then the mixture is placed on an automatic potentiometric titrator and titrated with a dilute hydrochloric acid solution of a certain concentration while stirring to obtain the actual molecular weight of the nylon active chain segment.

5. The preparation method according to claim 4, characterized in that In the step (3), the amount of the catalyst is 2‰ of the total mass of the nylon active chain segment and the dibasic acid; the amount of the antioxidant is 1‰ of the total mass of the nylon active chain segment and the dibasic acid; and the amount of the stabilizer is 1‰ of the total mass of the nylon active chain segment and the dibasic acid.

6. The preparation method according to claim 5, characterized in that The step (3) is specifically as follows: the molar number of the nylon active chain segment is calculated by the actual molecular weight of the nylon active chain segment titrated in (2); then, equal moles of the nylon active chain segment and the dibasic acid as well as the catalyst, stabilizer, antioxidant and appropriate amount of water are added into a high-temperature and high-pressure reactor, the air is first replaced by nitrogen, and then the temperature is raised to 5-10°C above the melting point of the dibasic acid and stabilized for 0.5-2 h, then the reaction is carried out at 190-220°C for 2 h, and then the small molecules in the system are slowly released at 220-230°C, and then the reaction is carried out at 230°C and 0 MPa for 1-2 h, and finally the reaction is carried out at 240-250°C and -0.09 MPa for 1-2 h to complete the polymerization; the system is restored to normal pressure, the reactor is opened, the amorphous all-bio-based furan copolyamide is quickly taken out and placed in deionized water, and then the amorphous all-bio-based furan copolyamide product is placed in a 60°C forced air drying oven and dried for 24 h.

7. A high barrier all-bio-based furan copolyamide film, characterized in that: Prepared according to any one of claims 1 to 6.

8. Use of the high-barrier all-biobased furan copolyamide film according to claim 7 in food packaging materials.

9. The use according to claim 8, characterized in that The food packaging material includes a food packaging film bag, a food packaging box or a food packaging bottle.

Images