Polymer compositions, methods for preparing same, and products

Abstract

A polymer composition, a method for preparing the same, and an article containing the polymer composition. The polymer composition includes a polyester graft copolymer and a polyester homopolymer, the polyester graft copolymer having a molecular weight higher than that of the polyester homopolymer. The polyester graft copolymer is represented by the following formula, where x, y1, y2, and z each independently represent a degree of polymerization, PM represents a polyester chain, the degree of polymerization of the polyester chain is p, and x and p each independently represent a number greater than 0, and y1, y2, and z each independently represent a number greater than or equal to 0. The polyester chains in the polyester homopolymer and the polyester graft copolymer are derived from the same polyester monomer. [Formula 1] JPEG2025528830000048.jpg57169

Description

Detailed Description of the Invention

[0001] [Technical Field] The present invention relates to the field of polymers, and further to polymer compositions comprising polyester graft copolymers and polyester homopolymers, methods for preparing the same, and articles comprising the same. More specifically, the present invention relates to polyglycolic acid compositions having a multimodal molecular weight distribution and methods for preparing the same.

[0002] 〔background〕 Polyglycolic acid (PGA), also known as polyglycolide or polyhydroxyacetic acid, is a fully biodegradable material that can be completely decomposed under natural conditions within 1 to 3 months. At the same time, PGA has excellent mechanical properties, strong barrier properties against O2 and CO2, and is non-toxic, harmless, green, and environmentally friendly. PGA has been certified as a safe, biodegradable plastic material in the United States, the European Union, and Japan.

[0003] However, polyglycolide, on the other hand, has a breaking elongation of only about 10% and a breaking elongation of 3 kJ / m 2 The polyglycolide obtained by the conventional preparation method has a notched impact strength of less than 1000 kJ / mol and poor toughness. On the other hand, the molecular weight of the polyglycolide obtained by the conventional preparation method is still not high enough, the melt flow rate at the processing temperature is too high, and the melt strength is too low, making it difficult to meet the application requirements of film blowing, rod extrusion, etc., which require a low melt flow rate. These drawbacks significantly limit the application of polyglycolide in the corresponding fields.

[0004] CN111647144A (Shanghai Pujing Chemical Technology Co., Ltd.) discloses a method for adjusting the molecular chain structure of polyglycolic acid by adding several characteristic functional groups (e.g., hydrophilic / hydrophobic groups -OH, -COOR) or chain segments with special properties (e.g., branching, copolymerization), thereby changing the molecular structure and thereby changing the original molecular properties of polyglycolic acid. This invention mentions that polyhydroxyl polymers such as polyethylene glycol or starch may be used as capping agents, and that the polymers are hydroxylated polymers with characteristic functional groups of multiple hydroxyl, carboxyl, or mixed hydroxyl and carboxyl (two or more) and number-average molecular weights of 2,000 to 10,000 g / mol. It also notes that excessively large molecular weights lead to lower efficiency due to steric hindrance effects and excessively long reaction times. Five minutes before the end of the reaction, SAG (epoxy polymer) or polyethylene glycol is added for capping, resulting in a final product with a low molecular weight (weight average molecular weight up to approximately 200,000 g / mol) and a low intrinsic viscosity of up to approximately 1.45 dL / g. At the same time, the initiator in this patent document only plays a role in branching or blocking. In addition, the polymerization conditions are low-temperature, nitrogen-protected reactions. The reaction conditions are harsh, and the reaction time is long, at least 50 minutes. Long reaction times can cause thermal decomposition or degradation of PGA, resulting in the formation of color- or odor-bearing by-products, significantly reducing the quality of the PGA product and limiting its application range.

[0005] CN112513133A (Shanghai Pujing Chemical Technology Co., Ltd.) relates to a novel polyglycolic acid. The polyglycolic acid in this patent is modified by isocyanate chain extension after polymerization, resulting in a melt strength of 5-30 cN at 230°C. However, on the other hand, isocyanates have higher toxicity, and the biodegradability of the resulting polyglycolic acid is also somewhat reduced by the isocyanate modification. On the other hand, this method requires post-polymerization modification, making the process complicated. In addition, this patent requires reaction at low temperature under nitrogen protection. The reaction conditions are harsh and the reaction time is long. The entire process takes at least 160 minutes.

[0006] In summary, there is a continuing need for solving the problem that polyglycolic acid cannot have low molecular weight, monomodal molecular weight distribution, high melt strength, and good processability at the same time, which cannot be met by existing technologies in the art.Therefore, how to improve melt strength while maintaining good processability, and how to reduce its melt flow rate at processing temperatures to better meet the application requirements of film blowing, rod extrusion, etc., which require a low melt flow rate, are urgent issues to be solved for polyglycolic acid materials.

[0007] Summary of the Invention In one aspect, the present invention provides a polymer composition comprising a polyester graft copolymer and a polyester homopolymer, the molecular weight of the polyester graft copolymer is higher than the molecular weight of the polyester homopolymer; And the polyester graft copolymer is represented by the following formula A:

[0008] [ka]

[0009] In Formula A, x, y1, y2, and z each independently represent a degree of polymerization; PM represents the polyester chain; and the degree of polymerization of the polyester chain is p; x and p each independently represent a number greater than 0, y1, y2, and z each independently represent a number greater than or equal to 0, The polyester homopolymer and the polyester chains in the polyester graft copolymer are derived from the same one or more monomers for polyester. The present invention relates to a polymer composition.

[0010] In some embodiments, for the polymer composition of the present invention, the sum of x, y1, y2, and z may be 50 or greater, preferably 50 to 6000, and more preferably 200 to 2500. In some embodiments, for the polymer composition of the present invention, p may be 40 or greater, preferably 50 or greater, and more preferably 70 to 2000. In some embodiments, for the polymer composition of the present invention, the ratio of z to the sum of x + y1 + y2 + z may be 0% to 50%. In some embodiments, for the polymer composition of the present invention, the ratio of y1 to the sum of x + y1 + y2 may be 0% to 32%.

[0011] In some embodiments, for the polymer composition of the present invention, the polyester graft copolymer and the polyester homopolymer are formed simultaneously in situ.

[0012] In some embodiments, for the polymer composition of the present invention, the polyester homopolymer and the polyester chains in the polyester graft copolymer are derived from hydroxy acid monomers or derivatives of hydroxy acid monomers; Preferably, the polyester homopolymer and the polyester chains in the polyester graft copolymer are derived from lactide monomers, lactone monomers, or a combination thereof; Preferably, the lactide monomer is an α-hydroxy acid or β-hydroxy acid based lactide monomer; More preferably, the lactide monomer is selected from the group consisting of glycolide, lactide, butyrolactide, valerolactide, caprolactide, and any combination thereof; Preferably, the lactone monomer is selected from the group consisting of β-butyrolactone, δ-valerolactone, ε-caprolactone, β-propiolactone, β-valerolactone, γ-butyrolactone, γ-valerolactone, γ-octalactone, β-methyl-δ-valerolactone, δ-stearolactone, 2-methyl-ε-caprolactone, 4-methyl-ε-caprolactone, ε-octalactone, ε-palmitolactone, and any combination thereof; More preferably, the lactone monomer is selected from the group consisting of β-butyrolactone, δ-valerolactone, ε-caprolactone, and any combination thereof; Most preferably, the monomer is selected from the group consisting of methyl glycolate, glycolic acid, glycolide, and any combination thereof.

[0013] In some embodiments, in the polymer composition of the present invention, when the polyester graft copolymer contains a polyvinyl alcohol main chain, the amount of the polyvinyl alcohol main chain in the polyester graft copolymer is 0.001 to 5 parts by mass, preferably 0.005 to 3 parts by mass, preferably 0.005 to 1 part by mass, more preferably 0.01 to 1 part by mass, relative to 100 parts by mass of polyester in the polyester graft copolymer and the polyester homopolymer, and / or When the polyester graft copolymer contains an ethylene-vinyl alcohol copolymer main chain, the amount of the ethylene-vinyl alcohol copolymer main chain in the polyester graft copolymer is 0.001 to 10 parts by mass, preferably 0.002 to 8 parts by mass, preferably 0.005 to 7 parts by mass, and more preferably 0.01 to 5 parts by mass, relative to 100 parts by mass of the polyester in the polyester graft copolymer and the polyester homopolymer.

[0014] In some embodiments, for the polymer composition of the present invention, the content of the polyester graft copolymer may be 0.1% by mass to 80.0% by mass, preferably 0.5% by mass to 55.0% by mass, and more preferably 1.0% by mass to 30.0% by mass, relative to the total mass of the polyester graft copolymer and the polyester homopolymer, and the content of the polyester homopolymer may be 20% by mass to 99.9% by mass, preferably 45.0% by mass to 99.5% by mass, and more preferably 70.0% by mass to 99.0% by mass.

[0015] In some embodiments, for the polymer composition of the present invention, the overall weight average molecular weight of the polymer composition may be 180,000 to 1,500,000 g / mol, preferably 200,000 to 1,500,000 g / mol, and more preferably 250,000 to 500,000 g / mol. In some embodiments, for the polymer composition of the present invention, the overall molecular weight polydispersity index of the polymer composition may be 1.5 to 20.0, preferably 2.0 to 12.0, preferably 2.0 to 6.0, and more preferably 2.0 to 3.5. In some embodiments, for the polymer composition of the present invention, the number of peaks in the molecular weight distribution of the polymer composition may be at least 2, preferably 2 to 4, for example, 2, 3, or 4.

[0016] In some embodiments, for the polymer composition of the present invention, the weight average molecular weight of the polyester graft copolymer may be 500,000 to 10,000,000 g / mol, preferably 1,000,000 to 6,000,000 g / mol. In some embodiments, for the polymer composition of the present invention, the molecular weight polydispersity index of the polyester graft copolymer may be 1.0 to 3.0, preferably 1.1 to 1.5. In some embodiments, for the polymer composition of the present invention, the weight average molecular weight of the polyester homopolymer may be 50,000 to 350,000 g / mol, preferably 100,000 to 200,000 g / mol. In some embodiments, for the polymer composition of the present invention, the molecular weight polydispersity index of the polyester homopolymer is 1.0 to 3.0, preferably 1.4 to 2.9.

[0017] The present invention provides a polyglycolic acid composition to solve the problems in the prior art that polyglycolic acid has a low molecular weight, a unimodal molecular weight distribution, and is unable to have both high melt strength and good processability, as well as the problems that the slow polymerization reaction of polyglycolic acid results in high production costs and energy consumption, and that polyglycolic acid articles have poor toughness and cannot meet the application requirements of the articles.

[0018] In another aspect, the present invention therefore provides a polymer composition comprising a polyester graft copolymer and a polyester homopolymer, the polyester graft copolymer is a polyglycolic acid graft copolymer, and the polyester homopolymer is a polyglycolic acid homopolymer; The present invention relates to a polymer composition. In this case, the polymer composition of the present invention may be referred to as a polyglycolic acid composition. In some embodiments, the molecular weight distribution of the polymer composition is multimodal. In the present invention, the molecular weight of the polyglycolic acid graft copolymer is higher than the molecular weight of the polyglycolic acid homopolymer. In the present invention, the polyglycolic acid graft copolymer and the polyglycolic acid homopolymer are formed simultaneously in situ.

[0019] In the present invention, when comparing the molecular weights of polyester graft copolymers, such as polyglycolic acid graft copolymers, and polyester homopolymers, such as polyglycolic acid homopolymers, the weight average molecular weight M w Weight average molecular weight M w , or number average molecular weight M n Logarithmic average molecular weight M n The same type of molecular weight is used, such as

[0020] In some embodiments, the polyester graft copolymer is a polyglycolic acid graft copolymer and the polyester homopolymer is a polyglycolic acid homopolymer; The polyglycolic acid graft copolymer is represented by formula (I):

[0021] [ka]

[0022] In formula (I), x, y1, y2, z, and p each independently represent a degree of polymerization; x and p each independently represent a number greater than 0, and y1, y2, and z each independently represent a number greater than or equal to 0.

[0023] In some embodiments, the sum of x, y1, y2, and z may be 50 or greater, preferably 50 to 6000, and more preferably 200 to 2500. In some embodiments, p may be 40 or greater, preferably 50 or greater, and more preferably 70 to 2000. In some embodiments, the ratio of z to the sum of x + y1 + y2 + z may be 0% to 50%. In some embodiments, the ratio of y1 to the sum of x + y1 + y2 may be 0% to 32%.

[0024] In some embodiments, the polyglycolic acid homopolymer is represented by formula (II):

[0025] [ka]

[0026] In formula (II), n1, , n i are the degrees of polymerization, i is directly linked to R

[0027] [ka]

[0028] where i≧1, M i is an imino group (-NH-), a nitrilo group

[0029] [ka]

[0030] or an ether bond (-O-), R is at least one of hydrogen, an aliphatic group, or an aromatic group; For i>1, M1, M2, . . ., M i are different from each other or the same as each other, and n1, n2,..., ni are different from each other or the same as each other.

[0031] In some embodiments, i can be any integer between 1 and 20, with a preferred range of i being 1 to 6; the sum of all n values ​​is 100 to 5000, preferably 1000 to 4000; R is hydrogen and / or an alkyl or aromatic hydrocarbon group with a molecular weight of 14 to 1000 g / mol.

[0032] In some embodiments, the polyglycolic acid segment

[0033] [ka]

[0034] For 100 parts by mass, the polymer composition comprises: When the polyglycolic acid graft copolymer contains a polyvinyl alcohol main chain, the amount of the polyglycolic acid graft copolymer is 0.001 to 5 parts by mass, preferably 0.005 to 3 parts by mass, preferably 0.005 to 1 part by mass, more preferably 0.01 to 1 part by mass.

[0035] [ka]

[0036] and / or When the polyglycolic acid graft copolymer contains an ethylene-vinyl alcohol copolymer main chain, the amount of the graft copolymer is 0.001 to 10 parts by mass, preferably 0.002 to 8 parts by mass, preferably 0.005 to 7 parts by mass, more preferably 0.01 to 5 parts by mass.

[0037] [ka]

[0038] and 0.001 to 1 part by mass, preferably 0.01 to 0.1 part by mass

[0039] [ka]

[0040] Contains:

[0041] In some embodiments, the overall weight average molecular weight of the polymer composition is 180,000 to 1,500,000 g / mol, preferably 200,000 to 1,500,000 g / mol, and more preferably 250,000 to 500,000 g / mol. In some embodiments, the overall molecular weight polydispersity index of the polymer composition is 1.5 to 20.0, preferably 2.0 to 12.0, preferably 2.0 to 6.0, and more preferably 2.0 to 3.5. In some embodiments, the number of peaks in the molecular weight distribution of the polymer composition is at least 2, preferably 2, 3, or 4.

[0042] In some embodiments, the weight average molecular weight of the polyglycolic acid graft copolymer is 500,000 to 10,000,000 g / mol, preferably 1,000,000 to 6,000,000 g / mol. In some embodiments, the molecular weight polydispersity index of the polyglycolic acid graft copolymer is 1.0 to 3.0, preferably 1.1 to 1.5. In some embodiments, the weight average molecular weight of the polyglycolic acid homopolymer is 50,000 to 350,000 g / mol, preferably 100,000 to 200,000 g / mol. In some embodiments, the molecular weight polydispersity index of the polyglycolic acid homopolymer is 1.0 to 3.0, preferably 1.4 to 2.9.

[0043] In some embodiments, based on the total weight of the polymer composition: the content of the polyglycolic acid graft copolymer is 0.1% by mass to 80.0% by mass, preferably 0.5% by mass to 55.0% by mass, and more preferably 1.0% by mass to 30.0% by mass; and The content of the polyglycolic acid homopolymer is 20% by mass to 99.9% by mass, preferably 45.0% by mass to 99.5% by mass, and more preferably 70.0% by mass to 99.0% by mass. In some embodiments, the melt flow rate of the polymer composition at 230°C / 2.16 kg is 20.0 g / 10 min or less, preferably 0.5 to 10.0 g / 10 min.

[0044] Another aspect of the present invention relates to a process for preparing a polymer composition of the present invention, such as the process for preparing a polymer composition disclosed in the above aspect, comprising melt polymerizing monomers for a polyester, a macromolecular initiator, and a small molecule initiator to provide the polymer composition.

[0045] In some embodiments, the monomer is selected from a hydroxy acid monomer or a derivative of a hydroxy acid monomer; Preferably, the monomers are selected from the group consisting of lactide monomers, lactone monomers, or combinations thereof; Preferably, the lactide monomer is an α-hydroxy acid or β-hydroxy acid based lactide monomer; More preferably, the lactide monomer is selected from the group consisting of glycolide, lactide, butyrolactide, valerolactide, caprolactide, and any combination thereof; Preferably, the lactone monomer is selected from the group consisting of β-butyrolactone, δ-valerolactone, ε-caprolactone, β-propiolactone, β-valerolactone, γ-butyrolactone, γ-valerolactone, γ-octalactone, β-methyl-δ-valerolactone, δ-stearolactone, 2-methyl-ε-caprolactone, 4-methyl-ε-caprolactone, ε-octalactone, ε-palmitolactone, and any combination thereof; More preferably, the lactone monomer is selected from the group consisting of β-butyrolactone, δ-valerolactone, ε-caprolactone, and any combination thereof; Most preferably, the monomer is selected from the group consisting of methyl glycolate, glycolic acid, glycolide, and any combination thereof; and / or The macroinitiator is at least one of polyvinyl alcohol and an ethylene-vinyl alcohol copolymer.

[0046] In some embodiments, the degree of alcoholysis of the polyvinyl alcohol is 68% to 99%. and / or The degree of polymerization of the polyvinyl alcohol is 100 to 6000, preferably 300 to 2000. In some embodiments, the content of ethylene segments in the ethylene-vinyl alcohol copolymer is greater than 0 mol% to 50 mol%. In some embodiments, the degree of polymerization of the ethylene-vinyl alcohol copolymer is 50 to 6000, preferably 300 to 2000. In some embodiments, the melt flow rate of the ethylene-vinyl alcohol copolymer at 190°C / 2.16 kg is 0.1 to 50.0 g / 10 min.

[0047] In some embodiments, the small molecule initiator is selected from the group consisting of water and / or hydroxyl and / or amino group-containing small molecule compounds having a boiling point greater than 160° C.; Preferably, the molecular weight of the hydroxyl and / or amino group-containing low molecular weight compound is 1000 g / mol or less, preferably 60 to 300 g / mol.

[0048] In some embodiments, the hydroxyl content, calculated as hydroxyl, contained in the macroinitiator for each gram of monomer is from 0.1 μmol / g monomer to 1.5 mmol / g monomer, preferably from 0.5 μmol / g monomer to 1.0 mmol / g monomer, and more preferably from 1.0 μmol / g monomer to 0.5 mmol / g monomer.

[0049] In some embodiments, the content of active hydrogen contained in the low molecular weight initiator, calculated as active hydrogen, for each gram of monomer is 3.0 μmol / g monomer to 40.0 μmol / g monomer, preferably 10.0 μmol / g monomer to 30.0 μmol / g monomer.

[0050] In some embodiments, the total content of active hydrogen, calculated as active hydrogen and contained in the polymeric initiator and the small molecule initiator for each gram of monomer, is 3.1 μmol / g monomer to 1.54 mmol / g monomer, preferably 10.5 μmol / g monomer to 1.03 mmol / g monomer, and more preferably 11.0 μmol / g monomer to 530.0 μmol / g monomer.

[0051] In this application, "active hydrogen" refers to the hydrogen contained in water, hydroxyl (-OH), primary amino (-NH), and secondary amino (-NH-). According to the present invention, each water molecule contains one "active hydrogen."

[0052] In some embodiments, the amount of the macroinitiator used per 100 parts by weight of the monomer is When the polymer initiator is polyvinyl alcohol, the amount is 0.001 to 5 parts by mass, preferably 0.005 to 3 parts by mass, preferably 0.005 to 1 part by mass, and more preferably 0.01 to 1 part by mass, and / or When the polymeric initiator is an ethylene-vinyl alcohol copolymer, the amount of the low molecular weight initiator used is 0.001 to 10 parts by mass, preferably 0.002 to 8 parts by mass, preferably 0.005 to 7 parts by mass, and more preferably 0.01 to 5 parts by mass, relative to 100 parts by mass of the monomer. In some embodiments, the amount of the low molecular weight initiator used is 0.001 to 1 part by mass, preferably 0.01 to 0.1 part by mass.

[0053] In some embodiments, the melt polymerization conditions include: a temperature of 120 to 300°C, preferably 160 to 250°C, more preferably 200 to 240°C; and / or a reaction time of 0.5 to 60 minutes, preferably 1 to 10 minutes; Includes:

[0054] In some embodiments, the melt polymerization reaction is carried out in a melt mixing device. In some embodiments, the melt polymerization reaction is carried out in a continuous twin screw extrusion system. In some embodiments, the polymerization reaction conditions in the continuous twin screw extrusion system are: a temperature of 180 to 250°C, preferably 210 to 240°C; and / or a screw rotation speed of 5 to 300 rpm, preferably 40 to 150 rpm; and / or a length-to-diameter ratio of 25 to 80, preferably 40 to 70; Includes:

[0055] In some embodiments, the melt polymerization reaction is carried out in at least two, e.g., two, three, or four, twin-screw extrusion systems connected in series. In some embodiments, the polymerization reaction conditions in each twin-screw extrusion system connected in series are: a temperature of 180 to 250°C, preferably 210 to 240°C; and / or a screw rotation speed of 5 to 300 rpm, preferably 40 to 150 rpm; and / or a length-to-diameter ratio of 25 to 80, preferably 40 to 70; Includes:

[0056] In some embodiments, the melt polymerization is carried out in the presence of a catalyst and, optionally, an antioxidant. In some embodiments, the catalyst is at least one salt compound of a metal element from Group IIA to Group VA and a transition metal element, or an organic guanidine catalyst. In some embodiments, the catalyst is at least one salt compound of Sn, Bi, Mg, Al, Ca, Fe, Mn, Ti, and Zn, and more preferably a Sn salt.

[0057] In some embodiments, the amount of the catalyst used is 0.005 to 1 part by mass, preferably 0.01 to 0.2 parts by mass, per 100 parts by mass of the monomer. In some embodiments, the amount of the antioxidant used is 0 to 2 parts by mass, preferably 0.01 to 1 part by mass, per 100 parts by mass of the monomer.

[0058] Another aspect of the present invention relates to polymer compositions prepared by the preparation methods of the present invention.

[0059] A further aspect of the present invention relates to an article comprising the polymer composition of the present invention, hi some embodiments, the article is selected from the group consisting of a film, a rod, a tube, a wire, a sheet, an irregularly shaped part, and any combination thereof.

[0060] In some embodiments, the article is a film. In some embodiments, the film is a multilayer composite film, At least one layer of the multilayer composite film comprises the polymer composition of the present invention.

[0061] DESCRIPTION OF THE DRAWINGS Figure 1 shows the GPC curves of Examples 1, 4, and 9, and Comparative Example 2. As can be seen from Figure 1, the conventional commercially available PGA (Comparative Example 2) has a peak molecular weight M of less than 500,000 g / mol. p (i.e., the lg(M w ) is less than 5.7), while Examples 1, 4, and 9 have a peak molecular weight M of less than 500,000 g / mol. p (i.e., polyglycolic acid homopolymer), as well as peaks with molecular weights M above 500,000 g / mol. p The polyglycolic acid graft copolymer has a multimodal molecular weight distribution, also having a peak with

[0062] Figure 2 shows the tensile stress-strain curves of the tensile tests of the injection-molded test pieces of Examples 1, 3, and 9, and Comparative Example 2. As can be seen from Figure 2, the elongation at break of the Examples of the present invention is significantly higher than that of Comparative Example 2 (commercially available PGA) while maintaining relatively high strength and modulus, i.e., the toughness is significantly improved.

[0063] Figure 3 shows the melt strength test results for Examples 1 and 9 and Comparative Example 2. As can be seen from Figure 3, the melt strength of Comparative Example 2 is less than 1 cN, while the melt strength of Example 1 at 230°C is significantly higher than that of Comparative Example 2 (commercial PGA) by up to about 20 cN.

[0064] Figure 4 is a schematic diagram of a multilayer coextrusion film blowing apparatus having a uniaxial stretching device. In the figure, 10a, 10b, and 10c are hoppers; 20a, 20b, and 20c are extruders; 30a, 30b, and 30c are melt pumps; 40a is a feed tube; 40b is a coextrusion distributor; 50a is a film blowing die; 50b is an air ring; 60 is a collapsing frame; 70a is a clamp roller; 80 is a uniaxial stretching device; 90 is a take-up roller; 01a is a film bubble; 01b is a precursor film; and 01c is a stretched film. The outer protective layer material, tie layer material, and barrier layer material (polymer compositions of the present invention, such as polyglycolic acid compositions) are added to hoppers 10a, 10b, and 10c, respectively.

[0065] Figure 5 is a schematic diagram of a multilayer coextrusion casting film production apparatus having a uniaxial stretching device, in which 10a, 10b, and 10c are hoppers, 20a, 20b, and 20c are extruders, 30a, 30b, and 30c are melt pumps, 40a is a feed pipe, 40b is a coextrusion distributor, 50c is a casting die, 70b is a cooling roller, 80 is a uniaxial stretching device, 90 is a take-up roller, 01b is a precursor film, and 01c is a stretched film.

[0066] FIG. 6 is a schematic diagram of the structure of a multilayer composite film according to an embodiment of the present invention.

[0067] Figure 7 is an optical microscope photograph of Example A2. As shown in Figure 7, the left and right sides of the photograph are metal sample supports, and the center is a cross-section of the multilayer film. The magnification of the photograph is 400x. As can be seen from the figure, the film is a five-layer composite film, with the lighter-colored layer in the center being a polyglycolic acid composition barrier layer having a thickness of approximately 15 μm, the outermost layer having a lighter color and a white reflectance being a polyethylene protective layer having a monolayer thickness of approximately 20 μm, and the darker layer between the barrier layer and the protective layer being a tie layer having a monolayer thickness of approximately 15 μm.

[0068] 8 is a scanning electron micrograph of a cross section of Comparative Example 4 (blended composition) at 200x magnification. The cross section is relatively smooth, with defects caused by large bubbles, which are attributed to brittle fracture.

[0069] 9 is a scanning electron micrograph of a cross section of Example 8 (in-situ synthesized composition) at 200x magnification. The cross section is relatively rough, belongs to ductile fracture, and has no obvious defects.

[0070] Detailed Description The present invention provides a polymer composition comprising a polyester graft copolymer and a polyester homopolymer. The present inventors have surprisingly found that by combining the polyester graft copolymer of the present invention and the polyester homopolymer, a composition can be provided that can overcome one or more of the above-mentioned problems in the prior art.

[0071] The polyester graft copolymer of the present invention is a polyester graft copolymer obtained by graft polymerizing polyester chains onto a polyvinyl alcohol and / or ethylene-vinyl alcohol copolymer backbone chain, and can be represented by the following formula A:

[0072] [ka]

[0073] In Formula A, x, y1, y2, and z each independently represent a degree of polymerization; PM represents the polyester chain; and the degree of polymerization of the polyester chain is p; x and p are each independently a number greater than 0, y1, y2, and z are each independently a number greater than or equal to 0, The polyester homopolymer and the polyester chains in the polyester graft copolymer are derived from the same one or more monomers for polyester.

[0074] In the present invention, the phrase "polyester chains in the polyester homopolymer and polyester graft copolymer derived from the same one or more monomers for polyester" means that the polyester chains in the polyester homopolymer and polyester graft copolymer are obtained by polymerizing the same polyester monomer or a mixture of the same polyester monomers.

[0075] In the polymer composition of the present invention, the polyester chains in the polyester graft copolymer and the polyester homopolymer are derived from hydroxy acid monomers or derivatives of hydroxy acid monomers. In some embodiments, the polyester chains in the polyester graft copolymer and the polyester homopolymer may be derived from lactide monomers, lactone monomers, or a combination thereof. The lactide monomer may be an α-hydroxy acid or β-hydroxy acid-based lactide monomer. Preferably, the lactide monomer is selected from the group consisting of glycolide, lactide, butyrolactide, valerolactide, caprolactide, and any combination thereof. Preferably, the lactone monomer may be selected from the group consisting of β-butyrolactone, δ-valerolactone, ε-caprolactone, β-propiolactone, β-valerolactone, γ-butyrolactone, γ-valerolactone, γ-octalactone, β-methyl-δ-valerolactone, δ-stearolactone, 2-methyl-ε-caprolactone, 4-methyl-ε-caprolactone, ε-octalactone, ε-palmitolactone, and any combination thereof; more preferably, the lactone monomer is selected from the group consisting of β-butyrolactone, δ-valerolactone, ε-caprolactone, and any combination thereof. Most preferably, the monomer is selected from the group consisting of methyl glycolate, glycolic acid, glycolide, and any combination thereof. In some embodiments, the present invention provides polyglycolic acid compositions having a multimodal molecular weight distribution and comprising a higher molecular weight polyglycolic acid graft copolymer (polyester graft copolymer) and a lower molecular weight polyglycolic acid homopolymer (polyester homopolymer). In these embodiments, the polyglycolic acid graft copolymer is a polyester graft copolymer obtained by grafting polyglycolic acid chains onto a polyvinyl alcohol and / or ethylene-vinyl alcohol copolymer backbone. The polyglycolic acid graft copolymer can be represented by the following formula (I):

[0076] [ka]

[0077] In formula (I), x, y1, y2, z, and p each independently represent a degree of polymerization; x and p are each independently a number greater than 0, and y1, y2, and z are each independently a number greater than or equal to 0.

[0078] As will be understood by those skilled in the art, in the polymer composition of the present invention, when the polyester chain in the polyester graft copolymer is a polyglycolic acid chain and the polyester homopolymer is a polyglycolic acid homopolymer, the polymer composition of the present invention is a polyglycolic acid composition.

[0079] In the present invention, polyvinyl alcohol and / or ethylene-vinyl alcohol copolymers are referred to as macroinitiators.

[0080] In formula (A) or formula (I), the sum of x, y1, y2, and z may be 50 or more, preferably 50 to 6000, and more preferably 200 to 2500, and / or p is 40 or more, preferably 50 or more, more preferably 70 to 2000; and / or The ratio of z to the sum of x + y1 + y2 + z is 0% to 50%. and / or The proportion of y1 to the sum of x+y1+y2 is 0% to 32%.

[0081] In some embodiments, the sum of x, y1, y2, and z is 50 or more, 60 or more, 70 or more, 80 or more, 90 or more, 100 or more, 110 or more, 120 or more, 130 or more, 140 or more, 150 or more, 160 or more, 170 or more, 180 or more, 190 or more, 200 or more, 210 or more, 220 or more, 230 or more, 240 or more, 250 or more, 260 or more, 270 or more, 280 or more, 290 or more, 300 or more, 310 or more, 320 or more, 330 or more, 340 or more, 350 or more, 360 or more, 370 or more, 380 or more, 390 or more, or 400 or more, and, 8000 or less, 7500 or less, 7000 or less, 6500 or less, 6000 or less, 5500 or less, 5000 or less, 4500 or less, 4000 or less, 3500 or less, 3000 or less, 2500 or less, 2400 or less, 2300 or less, 2200 or less, 2100 or less, 2000 or less, 1900 or less, 1800 or less, 1700 or less, 1600 or less, 1500 or less, 1400 or less, 1300 or less, 1200 or less, 1100 or less, 1000 or less, 900 or less, 800 or less, 700 or less, or 600 or less.

[0082] In some embodiments, when the main chain of the polyester graft copolymer or the polyglycolic acid graft copolymer is an ethylene-vinyl alcohol copolymer, the ratio of z to the sum of x + y1 + y2 + z may be 1% to 50%, preferably 20% to 45%, and the ratio of y1 to the sum of x + y1 + y2 may be 0.1% to 6.0%. In some embodiments, the percentage of z to the sum of x + y1 + y2 + z may be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, or 50%. In some embodiments, the ratio of y1 to the sum of x+y1+y2 is 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.1%. It may be 8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4.0%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, 5.0%, 5.1%, 5.2%, 5.3%, 5.4%, 5.5%, 5.6%, 5.7%, 5.8%, 5.9%, or 6.0%.

[0083] In some embodiments, when the backbone of the polyester graft copolymer or the polyglycolic acid graft copolymer is polyvinyl alcohol, z may be 0, and the ratio of y1 to the sum of x + y1 + y2 may be 1% to 32%. In some embodiments, the ratio of y1 to the sum of x + y1 + y2 may be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, or 32%.

[0084] The sum of x + y1 + y2 + z is the (total) degree of polymerization of polyvinyl alcohol or ethylene-vinyl alcohol copolymer. As known to those skilled in the art, the degree of polymerization can be determined from information such as the number average molecular weight of polyvinyl alcohol or ethylene-vinyl alcohol copolymer and the degree of alcoholysis of the raw material. The ratio of z to the sum of x + y1 + y2 + z is the ethylene content, which is usually a known parameter of the raw material product and can also be calculated by the integrated area of ​​the corresponding characteristic peak in the nuclear magnetic resonance hydrogen spectrum.

[0085] For polyvinyl alcohol, the ratio of x + y2 to the sum of x + y1 + y2 is the degree of alcoholysis of the polyvinyl alcohol. For ethylene-vinyl alcohol copolymer, the ratio of x + y2 to the sum of x + y1 + y2 is the degree of alcoholysis of the ethylene-vinyl alcohol copolymer. The degree of alcoholysis is usually a known parameter of the raw product, but can also be measured by nuclear magnetic resonance, infrared, near-infrared, and other testing methods.

[0086] The degree of polymerization of the polyester chain of the polyester graft copolymer or the polyglycolic acid chain of the polyglycolic acid graft copolymer is p. According to the present invention, p may be 40 or more, and preferably p is 50 or more; and, p is 3,000 or less, preferably 2,000 or less, and preferably 1,000 or less.

[0087] The value of p can be calculated by the following formula (a): p=(M2-M0) / (x*M m ) (a) In the above formula (a), M2 and M0 are the number average molecular weights of the polyester graft copolymer and the macroinitiator, respectively, in g / mol. x is the degree of polymerization in formula A or formula (I), and its value can be determined by a test method such as nuclear magnetic resonance testing. M m is the molecular weight of the polyester repeat unit, for example, when the monomer is glycolide, M m is 58 g / mol.

[0088] Alternatively, a lower bound on the value of p can be calculated by the following formula (b): p>(M2-M0) / [(x+y2)*M m ] (b) In the above formula (b), M2, M0, and M m is as explained above for formula (a). x + y2 is the degree of polymerization of the hydroxyl-containing repeating unit in the polymer initiator, and its value can be calculated from the degree of alcoholysis, the ethylene content, and the total degree of polymerization, and the calculation method is as follows: Degree of alcohol decomposition*(1-ethylene content)*total degree of polymerization is.

[0089] Alternatively, the value of p can be obtained in the following manner: obtain a polymer composition, completely hydrolyze the polymer composition (i.e., completely hydrolyze the polyester chains to small molecules), recover the macroinitiator, characterize its structure, and then obtain the value of p according to the method disclosed in the present invention.

[0090] For example, the polymer composition may be added to water at 60 to 80°C until it is completely hydrolyzed (i.e., the polyester chains are completely hydrolyzed to low molecular weight molecules), and then the water is removed by vacuum distillation, vacuum freeze drying, physical adsorption, or the like. The residue is then dissolved in a solvent such as dimethyl sulfoxide, and the polymeric initiator is then isolated (for example, by chromatography, etc.), its structure is characterized, and the number average molecular weight and hydroxyl content (x + y value) of the polymeric initiator are determined, and the value of p may be determined according to the method disclosed in the present invention.

[0091] In the examples according to the present invention, the p values ​​for the resulting polymers, calculated by formula (b), are all greater than 40.

[0092] When the polymer composition of the present invention, such as a polyglycolic acid composition, is subjected to GPC measurement, it gives a GPC curve characterized by a multimodal molecular weight distribution, and the GPC curve indicates that the polymer composition contains at least two polymer components having different molecular weights. When the GPC curve has a bimodal molecular weight distribution, the peak with a higher molecular weight is a polyester graft copolymer, such as a polyglycolic acid graft copolymer, and the peak with a lower molecular weight is a polyester homopolymer, such as a polyglycolic acid homopolymer.

[0093] When the polymer composition containing the polyester graft copolymer of the present invention and a polyester homopolymer is a polyglycolic acid composition containing a polyglycolic acid graft copolymer (polyester graft copolymer) and a polyglycolic acid homopolymer (polyester homopolymer), the polyglycolic acid homopolymer is represented by formula (II):

[0094] [ka]

[0095] In formula (II), n1, , n iis the degree of polymerization, i is directly linked to R

[0096] [ka]

[0097] where i≧1, M i is an imino group (-NH-), a nitrilo group

[0098] [ka]

[0099] or an ether bond (-O-), R is at least one of hydrogen, an aliphatic group, or an aromatic group; For i>1, M1, M2, . . ., M i are different from each other or the same as each other, and n1, n2,..., n i are different from each other or the same as each other. In some embodiments, when i=1, R may be a hydrogen atom or a hydrocarbyl group.

[0100] According to the present invention, preferably, the range of integer i may be 1 to 20, and the preferred range of integer i may be 1 to 6, for example, i may be 1, 2, 3, 4, 5, or 6. In some embodiments, the sum of all n values ​​(n1 + n2 + + n i ) is 100 to 5000, preferably 1000 to 4000, R is hydrogen and / or an alkyl or aromatic hydrocarbon group with a molecular weight of 14 to 1000 g / mol.

[0101] According to the present invention, the sum of the n values ​​in formula (II) is the degree of polymerization. In some embodiments of the present invention, the sum of all n values ​​in formula (II) is between 1000 and 4000.

[0102] According to the present invention, the sum of all n values ​​can be determined by dividing the number average molecular weight of a polyester homopolymer, such as a polyglycolic acid homopolymer, by the molecular weight of the repeat unit, as determined by GPC.

[0103] According to the present invention, the calculated degrees of polymerization (x, y1, y2, z, p, and n) are average values ​​and are rounded during the calculation.

[0104] According to the present invention, in the polymer composition of the present invention containing the polyester graft copolymer and the polyester homopolymer, the content of the polyester graft copolymer is preferably 100 parts by mass of the polyester in the polyester graft copolymer and the polyester homopolymer (i.e., the parts by mass of the polyester homopolymer + the parts by mass of the polyester chain in the polyester graft copolymer), When the polyester graft copolymer contains a polyvinyl alcohol main chain, the amount of the polyvinyl alcohol main chain in the polyester graft copolymer is 0.001 to 5 parts by mass, preferably 0.005 to 3 parts by mass, preferably 0.005 to 1 part by mass, and more preferably 0.01 to 1 part by mass, and / or When the polyester graft copolymer contains an ethylene-vinyl alcohol copolymer main chain, the amount of the ethylene-vinyl alcohol copolymer main chain in the polyester graft copolymer is 0.001 to 10 parts by mass, preferably 0.002 to 8 parts by mass, preferably 0.005 to 7 parts by mass, and more preferably 0.01 to 5 parts by mass.

[0105] In some embodiments, in the polymer composition of the present invention comprising the polyester graft copolymer and the polyester homopolymer, when the polyester graft copolymer comprises a polyvinyl alcohol main chain, the amount (parts by weight) of the polyvinyl alcohol main chain in the polyester graft copolymer is 0.001 parts, 0.002 parts, 0.003 parts, 0.004 parts, 0.005 parts, 0.006 parts, 0.007 parts, 0.008 parts, 0.009 parts, 0.010 parts, 0.011 parts, 0.012 parts, 0.013 parts, 0.014 parts, 0.015 parts, 0.016 parts, 0.017 parts, 0.018 parts, 0.019 parts, 0.020 parts, 0.021 parts, 0.022 parts, 0.023 parts, 0.024 parts, 0.025 parts, 0.026 parts, 0.027 parts, 0.028 parts, 0.029 parts, 0.030 parts, 0.031 parts, 0.032 parts, 0.033 parts, 0.034 parts, 0.035 parts, 0.036 parts, 0.037 parts, 0.038 parts, 0.039 parts, 0.040 parts, 0.041 parts, 0.042 parts, 0.043 parts, 0.044 parts, 0.045 parts, 0.046 parts, 0.047 parts, 0.048 parts, 0.049 parts, 0.050 parts, 0.051 parts, 0.052 parts, 0.053 parts, 0.054 parts, 0.055 parts, 0.056 12 parts, 0.013 parts, 0.014 parts, 0.015 parts, 0.016 parts, 0.017 parts, 0.018 parts, 0.019 parts, 0.020 parts, 0.021 parts, 0.022 parts, 0.023 parts, 0.0 24 copies, 0.025 copies, 0.026 copies, 0.027 copies, 0.028 copies, 0.029 copies, 0.030 copies, 0.035 copies, 0.040 copies, 0.050 copies, 0.060 copies, 0.070 copies, 0.08 0 parts, 0.090 parts, 0.10 parts, 0.11 parts, 0.12 parts, 0.13 parts, 0.14 parts, 0.15 parts, 0.16 parts, 0.17 parts, 0.18 parts, 0.19 parts, 0.20 parts, 0.30 parts, 0.40 parts, 0.50 parts, 0.60 parts, 0.70 parts, 0.80 parts, 0.90 parts, 1.0 parts, 1.5 parts, 2.0 parts, 2.5 parts, 3.0 parts, 3.5 parts, 4.0 parts, 4.5 parts, or 5.0 parts.In some embodiments, in the polymer composition of the present invention comprising the polyester graft copolymer and the polyester homopolymer, when the polyester graft copolymer comprises an ethylene-vinyl alcohol copolymer main chain, the amount (parts by weight) of the ethylene-vinyl alcohol copolymer main chain in the polyester graft copolymer is 0.001 parts, 0.002 parts, 0.003 parts, 0.004 parts, 0.005 parts, 0.006 parts, 0.007 parts, 0.008 parts, 0.009 parts, 0.010 parts, 0.011 parts, 0.012 parts, 0.013 parts, 0.014 parts, 0.015 parts, 0.016 parts, 0.017 parts, 0.018 parts, 0.019 parts, 0.020 parts, 0.021 parts, 0.022 parts, 0.023 parts, 0.024 parts, 0.025 parts, 0.026 parts, 0.027 parts, 0.028 parts, 0.029 parts, 0.030 parts, 0.031 parts, 0.032 parts, 0.033 parts, 0.034 parts, 0.035 parts, 0.036 parts, 0.037 parts, 0.038 parts, 0.039 parts, 0.040 parts, 0.041 parts, 0.042 parts, 0.043 parts, 0.044 parts, 0.045 parts, 0.046 parts, 0.047 parts, 0.048 parts, 0.049 parts, 0.050 parts, 0.051 parts, 0.052 parts, 0.053 parts, 0.054 parts, 0.055 parts, 3 parts, 0.014 parts, 0.015 parts, 0.016 parts, 0.017 parts, 0.018 parts, 0.019 parts, 0.020 parts, 0.021 parts, 0.022 parts, 0.023 parts, 0.024 parts, 0.025 parts, 0.0 26 copies, 0.027 copies, 0.028 copies, 0.029 copies, 0.030 copies, 0.035 copies, 0.040 copies, 0.050 copies, 0.060 copies, 0.070 copies, 0.080 copies, 0.090 copies, 0.10 copies, 0.1 It may be 1 part, 0.12 parts, 0.13 parts, 0.14 parts, 0.15 parts, 0.16 parts, 0.17 parts, 0.18 parts, 0.19 parts, 0.20 parts, 0.30 parts, 0.40 parts, 0.50 parts, 0.60 parts, 0.70 parts, 0.80 parts, 0.90 parts, 1.0 parts, 1.5 parts, 2.0 parts, 2.5 parts, 3.0 parts, 3.5 parts, 4.0 parts, 4.5 parts, 5.0 parts, 6.0 parts, 7.0 parts, 8.0 parts, 9.0 parts, or 10.0 parts.

[0106] According to the present invention, the polymer composition of the present invention comprising the polyester graft copolymer and the polyester homopolymer is The content of the polyester graft copolymer is 0.1% by mass to 80.0% by mass, preferably 0.5% by mass to 55.0% by mass, and more preferably 1.0% by mass to 30.0% by mass. For example, the content of the polyester graft copolymer is 1.0% by mass, 2.0% by mass, 3.0% by mass, 4.0% by mass, 5.0% by mass, 6.0% by mass, 7.0% by mass, 8.0% by mass, 9.0% by mass, 10.0% by mass, 11.0% by mass, 12.0% by mass, 13.0% by mass, 14.0% by mass, 15.0% by mass, 16.0% by mass, 17.0% by mass, 18.0% by mass, 19.0% by mass, 20.0% by mass, 21.0% by mass, 22.0% by mass, 23.0% by mass, 24.0% by mass, 25.0% by mass, 26.0% by mass, 27.0% by mass, 28.0% by mass, 29.0% by mass, 30.0% by mass, 31.0% by mass, 32.0% by mass, 33.0% by mass, 34.0% by mass, 35.0% by mass, 36.0% by mass, 37.0% by mass, 38.0% by mass, 39.0% by mass, 39.0% by mass, 30.0% by mass, 31.0% by mass, 32.0% by mass, 33.0% by mass, 34.0% by mass, 35.0% by mass, 36.0% by mass, 37.0% by mass, 38.0% by mass, 0% by mass, 10% by mass, 11% by mass, 12% by mass, 13% by mass, 14% by mass, 15% by mass, 16% by mass, 17% by mass, 18% by mass, 19% by mass, 20% by mass, 21% by mass, 22% by mass, 23 % by mass, 24% by mass, 25% by mass, 26% by mass, 27% by mass, 28% by mass, 29% by mass, 30% by mass, 35% by mass, 40% by mass, 45% by mass, 50% by mass, or 55% by mass, and The content of the polyester homopolymer is 20% by mass to 99.9% by mass, preferably 45.0% by mass to 99.5% by mass, and more preferably 70.0% by mass to 99.0% by mass. For example, the content of the polyester homopolymer is 25.0% by mass, 30.0% by mass, 35.0% by mass, 40.0% by mass, 45.0% by mass, 50.0% by mass, 55.0% by mass, 60.0% by mass, 65.0% by mass, 70.0% by mass, 71.0% by mass, 72.0% by mass, 73.0% by mass, 74.0% by mass, 75.0% by mass, 76.0% by mass, 77.0% by mass, 78.0% by mass, 79.0% by mass, 80.0% by mass, 81.0% by mass, 82.0% by mass, 83.0% by mass, 84.0% by mass, 85.0% by mass, 86.0% by mass, 87.0% by mass, 88.0% by mass, 89.0% by mass, 90.0% by mass, 91.0% by mass, 92.0% by mass, 93.0% by mass, 94.0% by mass, 95.0% by mass, 96.0% by mass, 97.0% by mass, 98.0% by mass, 99.0% by mass, 99.0% by mass, 99.0% by mass, 10 ... Mass%, 75.0 mass%, 76.0 mass%, 77.0 mass%, 78.0 mass%, 79.0 mass%, 80.0 mass%, 81.0 mass%, 82.0 mass%, 83.0 mass%, 84.0 mass%, 85.0 mass%, 86.0 mass%, 87.0 mass% , 88.0% by mass, 89.0% by mass, 90.0% by mass, 91.0% by mass, 92.0% by mass, 93.0% by mass, 94.0% by mass, 95.0% by mass, 96.0% by mass, 97.0% by mass, 98.0% by mass, or 99.0% by mass.

[0107] According to the present invention, the polyglycolic acid segment

[0108] [ka]

[0109] 100 parts by mass (i.e.,

[0110] [ka]

[0111] The total mass of the

[0112] [ka]

[0113] is the formula (I)

[0114] [ka]

[0115] and in formula (II)

[0116] [ka]

[0117] the polyglycolic acid composition of the present invention, which comprises the polyglycolic acid graft copolymer and the polyglycolic acid homopolymer, When the polyglycolic acid graft copolymer contains a polyvinyl alcohol main chain, the amount is 0.001 to 5 parts by mass, preferably 0.005 to 3 parts by mass, preferably 0.005 to 1 part by mass, and more preferably 0.01 to 1 part by mass (for example, 0.001 parts, 0.002 parts, 0.003 parts, 0.004 parts, 0.005 parts, 0.006 parts, 0.007 parts, 0.008 parts, 0.009 parts, 0.010 parts, 0.011 parts, 0.012 parts, 0.013 parts, 0.014 parts, 0.015 parts, 0.016 parts, 0.017 parts, 0.018 parts, 0.019 parts, 0.020 parts, 0.021 parts, 0.022 parts, 0. 023 parts, 0.024 parts, 0.025 parts, 0.026 parts, 0.027 parts, 0.028 parts, 0.029 parts, 0.030 parts, 0.035 parts, 0.04 0 parts, 0.050 parts, 0.060 parts, 0.070 parts, 0.080 parts, 0.090 parts, 0.10 parts, 0.11 parts, 0.12 parts, 0.13 parts, 0.1 4 parts, 0.15 parts, 0.16 parts, 0.17 parts, 0.18 parts, 0.19 parts, 0.20 parts, 0.30 parts, 0.40 parts, 0.50 parts, 0.60 parts, 0.70 parts, 0.80 parts, 0.90 parts, 1.0 parts, 1.5 parts, 2.0 parts, 2.5 parts, 3.0 parts, 3.5 parts, 4.0 parts, 4.5 parts, or 5.0 parts)

[0118] [ka]

[0119] (wherein z=0), and 0.001 to 1 part by mass (for example, 0.001 parts, 0.002 parts, 0.003 parts, 0.004 parts, 0.005 parts, 0.006 parts, 0.007 parts, 0.008 parts, 0.009 parts, 0.010 parts, 0.011 parts, 0.012 parts, 0.013 parts, 0.014 parts, 0.015 parts, 0.016 parts, 0.017 parts, 0.018 parts, 0.019 parts, 0.020 parts, 0.0 21 copies, 0.022 copies, 0.023 copies, 0.024 copies, 0.025 copies, 0.026 copies, 0.027 copies, 0.028 copies, 0.029 copies, 0.030 copies, 0.031 copies, 0.032 part, 0.033 part, 0.034 part, 0.035 part, 0.036 part, 0.037 part, 0.038 part, 0.039 part, 0.040 part, 0.041 part, 0.042 part, 0.043 part, 0 .044 part, 0.045 part, 0.046 part, 0.047 part, 0.048 part, 0.049 part, 0.050 part, 0.051 part, 0.052 part, 0.053 part, 0.054 part, 0.0 55 copies, 0.056 copies, 0.057 copies, 0.058 copies, 0.059 copies, 0.060 copies, 0.061 copies, 0.062 copies, 0.063 copies, 0.064 copies, 0.065 copies, 0.066 copies , 0.067 parts, 0.068 parts, 0.069 parts, 0.070 parts, 0.080 parts, 0.090 parts, 0.10 parts, 0.11 parts, 0.12 parts, 0.13 parts, 0.14 parts, 0.15 parts, 0.16 parts, 0.17 parts, 0.18 parts, 0.19 parts, 0.20 parts, 0.30 parts, 0.40 parts, 0.50 parts, 0.60 parts, 0.70 parts, 0.80 parts, 0.90 parts, or 1.0 parts)

[0120] [ka]

[0121] Contains:

[0122] According to the present invention, the polyglycolic acid segment

[0123] [ka]

[0124] 100 parts by mass (i.e.,

[0125] [ka]

[0126] The total mass of the

[0127] [ka]

[0128] is the formula (I)

[0129] [ka]

[0130] and in formula (II)

[0131] [ka]

[0132] the polyglycolic acid composition of the present invention, which comprises the polyglycolic acid graft copolymer and the polyglycolic acid homopolymer, When the polyglycolic acid graft copolymer contains an ethylene-vinyl alcohol copolymer main chain, the amount is 0.001 to 10 parts by mass, preferably 0.002 to 8 parts by mass, preferably 0.005 to 7 parts by mass, and more preferably 0.01 to 5 parts by mass (for example, 0.001 parts, 0.002 parts, 0.003 parts, 0.004 parts, 0.005 parts, 0.006 parts, 0.007 parts, 0.008 parts, 0.009 parts, 0.010 parts, 0.011 parts, 0.012 parts, 0.013 parts, 0.014 parts, 0.015 parts, 0.016 parts, 0.017 parts, 0.018 parts, 0.019 parts, 0.020 parts, 0.021 parts, 0.022 parts, 0.023 parts, 0.0 24 parts, 0.025 parts, 0.026 parts, 0.027 parts, 0.028 parts, 0.029 parts, 0.030 parts, 0.035 parts, 0.040 parts, 0.050 parts, 0. 060 parts, 0.070 parts, 0.080 parts, 0.090 parts, 0.10 parts, 0.11 parts, 0.12 parts, 0.13 parts, 0.14 parts, 0.15 parts, 0.16 parts, 0. 17 parts, 0.18 parts, 0.19 parts, 0.20 parts, 0.30 parts, 0.40 parts, 0.50 parts, 0.60 parts, 0.70 parts, 0.80 parts, 0.90 parts, 1.0 parts, 1.5 parts, 2.0 parts, 2.5 parts, 3.0 parts, 3.5 parts, 4.0 parts, 4.5 parts, 5.0 parts, 6.0 parts, 7.0 parts, 8.0 parts, 9.0 parts, or 10.0 parts)

[0133] [ka]

[0134] Contains and 0.001 to 1 part by mass (for example, 0.001 parts, 0.002 parts, 0.003 parts, 0.004 parts, 0.005 parts, 0.006 parts, 0.007 parts, 0.008 parts, 0.009 parts, 0.010 parts, 0.011 parts, 0.012 parts, 0.013 parts, 0.014 parts, 0.015 parts, 0.016 parts, 0.017 parts, 0.018 parts, 0.019 parts, 0.020 parts, 0.02 1 part, 0.022 part, 0.023 part, 0.024 part, 0.025 part, 0.026 part, 0.027 part, 0.028 part, 0.029 part, 0.030 part, 0.031 part, 0.032 part , 0.033 parts, 0.034 parts, 0.035 parts, 0.036 parts, 0.037 parts, 0.038 parts, 0.039 parts, 0.040 parts, 0.041 parts, 0.042 parts, 0.043 parts, 0. 044 copies, 0.045 copies, 0.046 copies, 0.047 copies, 0.048 copies, 0.049 copies, 0.050 copies, 0.051 copies, 0.052 copies, 0.053 copies, 0.054 copies, 0.05 5 copies, 0.056 copies, 0.057 copies, 0.058 copies, 0.059 copies, 0.060 copies, 0.061 copies, 0.062 copies, 0.063 copies, 0.064 copies, 0.065 copies, 0.066 copies, 0.067 parts, 0.068 parts, 0.069 parts, 0.070 parts, 0.080 parts, 0.090 parts, 0.10 parts, 0.11 parts, 0.12 parts, 0.13 parts, 0.14 parts, 0.15 parts, 0.16 parts, 0.17 parts, 0.18 parts, 0.19 parts, 0.20 parts, 0.30 parts, 0.40 parts, 0.50 parts, 0.60 parts, 0.70 parts, 0.80 parts, 0.90 parts, or 1.0 parts)

[0135] [ka]

[0136] Contains:

[0137] The mass content of each of the segments / structures / polymer chains may be tested by methods well known in the art, such as nuclear magnetic resonance and / or infrared spectroscopy. Alternatively, the mass content of each of the segments / structures / polymer chains may be calculated by the amount of charge during the preparation process.

[0138] The polymer composition of the present invention has a weight average molecular weight of 180,000 to 1,500,000 g / mol, preferably 200,000 to 1,500,000 g / mol, and more preferably 250,000 to 500,000 g / mol. For example, the weight average molecular weight of the polymer composition may be 180,000 g / mol, 190,000 g / mol, 200,000 g / mol, 210,000 g / mol, 220,000 g / mol, 230,000 g / mol, 240,000 g / mol, 250,000 g / mol, 300,000 g / mol, 350,000 g / mol, 400,000 g / mol, 450,000 g / mol, 500,000 g / mol, 600,000 g / mol, 700,000 g / mol, 800,000 g / mol, 900,000 g / mol, 1000,000 g / mol, 1100,000 g / mol, 1200,000 g / mol, 1300,000 g / mol, 1400,000 g / mol, 1500,000 g / mol, 1600,000 g / mol, 1700,000 g / mol, 1800,000 g / mol, 1900,000 g / mol, 2000,000 g / mol, 2100,000 g / mol, 2200,000 g / mol, 2300,000 g / mol, 2400,000 g / mol, 2500,000 g / mol, The molecular weight may be 00 g / mol, 600,000 g / mol, 700,000 g / mol, 800,000 g / mol, 900,000 g / mol, 1,000,000 g / mol, 1,100,000 g / mol, 1,200,000 g / mol, 1,300,000 g / mol, 1,400,000 g / mol, or 1,500,000 g / mol, or may be a range formed by any two of the above values. "Overall weight average molecular weight" refers to the weight average molecular weight of the entire polymer composition. For the polymer composition of the present invention, the overall molecular weight polydispersity index of the polymer composition may be 1.5 to 20.0, preferably 2.0 to 12.0, preferably 2.0 to 6.0, and more preferably 2.0 to 3.5. For the polymer composition of the present invention, the number of peaks in its molecular weight distribution, as measured by GPC, is at least two, preferably two, three, or four.

[0139] In the polymer composition of the present invention, the weight average molecular weight of the polyester graft copolymer is 500,000 to 10,000,000 g / mol, preferably 1,000,000 to 7,000,000 g / mol, more preferably 1,000,000 to 6,000,000 g / mol, for example, 1,000,000 g / mol, 1,500,000 g / mol, 2,000,000 g / mol, 3,000,000 g / mol, 4,000,000 g / mol, 5,000,000 g / mol, or 6,000,000 g / mol, or may be a range formed by any two of the above values. The molecular weight polydispersity index of the polyester graft copolymer is 1.0 to 3.0, preferably 1.1 to 1.5. In the polymer composition of the present invention, the weight average molecular weight of the polyester homopolymer is 50,000 to 350,000 g / mol, preferably 100,000 to 200,000 g / mol, for example, 60,000 g / mol, 70,000 g / mol, 80,000 g / mol, 90,000 g / mol, 100,000 g / mol, 120,000 g / mol, 140,000 g / mol, 160,000 g / mol, The molecular weight polydispersity index of the polyester homopolymer is 1.0 to 3.0, preferably 1.4 to 2.9.

[0140] The overall weight average molecular weight of the polyglycolic acid composition of the present invention may be 180,000 to 1,500,000 g / mol, preferably 200,000 to 1,500,000 g / mol, and more preferably 250,000 to 500,000 g / mol, for example, 180,000 g / mol, 190,000 g / mol, 200,000 g / mol, 210,000 g / mol, 220,000 g / mol, 230,000 g / mol, 240,000 g / mol, 250,000 g / mol, 300,000 g / mol , 350,000 g / mol, 400,000 g / mol, 450,000 g / mol, 500,000 g / mol, 600,000 g / mol, 700,000 g / mol, 800,000 g / mol, 900,000 g / mol, 1,000,000 g / mol, 1,100,000 g / mol, 1,200,000 g / mol, 1,300,000 g / mol, 1,400,000 g / mol, or 1,500,000 g / mol, or a range formed by any two of the above values.

[0141] According to the present invention, the overall molecular weight polydispersity index of the polyglycolic acid composition may be 1.5 to 20.0, preferably 2.0 to 12.0, preferably 2.0 to 6.0, and more preferably 2.0 to 3.5.

[0142] According to the present invention, the number of peaks in the molecular weight distribution of the polyglycolic acid composition is at least two, including but not limited to, for example, two, three, or four peaks.

[0143] According to the present invention, the weight average molecular weight of the polyglycolic acid graft copolymer in the polyglycolic acid composition may be 500,000 to 10,000,000 g / mol, preferably 1,000,000 to 7,000,000 g / mol, and more preferably 1,000,000 to 6,000,000 g / mol, for example, 1,000,000 g / mol, 1,500,000 g / mol, 2,000,000 g / mol, 3,000,000 g / mol, 4,000,000 g / mol, 5,000,000 g / mol, or 6,000,000 g / mol, or may be a range formed by any two of the above values.

[0144] According to the present invention, the molecular weight polydispersity index of the polyglycolic acid graft copolymer in the polyglycolic acid composition may be 1.0 to 3.0, preferably 1.1 to 1.5.

[0145] According to the present invention, the weight average molecular weight of the polyglycolic acid homopolymer in the polyglycolic acid composition is 50,000 to 350,000 g / mol, preferably 100,000 to 200,000 g / mol, for example, 60,000 g / mol, 70,000 g / mol, 80,000 g / mol, 90,000 g / mol, 100,000 g / mol, 120,000 g / mol, 140,000 g / mol, 160, 000 g / mol, 180,000 g / mol, 200,000 g / mol, 220,000 g / mol, 240,000 g / mol, 260,000 g / mol, 280,000 g / mol, 300,000 g / mol, 320,000 g / mol, 330,000 g / mol, 340,000 g / mol, or 350,000 g / mol, or a range formed by any two of the above values.

[0146] According to the present invention, the molecular weight polydispersity index of the polyglycolic acid homopolymer in the polyglycolic acid composition may be 1.0 to 3.0, preferably 1.4 to 2.9.

[0147] According to the present invention, the content of the polyglycolic acid graft copolymer and the polyglycolic acid homopolymer in the polyglycolic acid composition can be selected within a wide range. In some embodiments of the present invention, the content of the polyglycolic acid graft copolymer and the polyglycolic acid homopolymer is: The content of the polyglycolic acid graft copolymer is 0.1% by mass to 80.0% by mass, preferably 0.5% by mass to 55.0% by mass, and more preferably 1.0% by mass to 30.0% by mass. For example, the content of the polyglycolic acid graft copolymer is 1.0% by mass, 2.0% by mass, 3.0% by mass, 4.0% by mass, 5.0% by mass, 6.0% by mass, 7.0% by mass, 8.0% by mass, 9.0% by mass, 10.0% by mass, 11.0% by mass, 12.0% by mass, 13.0% by mass, 14.0% by mass, 15.0% by mass, 16.0% by mass, 17.0% by mass, 18.0% by mass, 19.0% by mass, 20.0% by mass, 21.0% by mass, 22.0% by mass, 23.0% by mass, 24.0% by mass, 25.0% by mass, 26.0% by mass, 27.0% by mass, 28.0% by mass, 29.0% by mass, 30.0% by mass, 31.0% by mass, 32.0% by mass, 33.0% by mass, 34.0% by mass, 35.0% by mass, 36.0% by mass, 37.0% by mass, 38.0% by mass, 39.0% by mass, 39.0% by mass, 39.0% by mass, 30.0% by mass, 30.0% by mass, 31.0% by mass, 32.0% by mass, 33.0% by mass, 34.0% by mass, 35.0% by mass, 3 .0 mass%, 10 mass%, 11 mass%, 12 mass%, 13 mass%, 14 mass%, 15 mass%, 16 mass%, 17 mass%, 18 mass%, 19 mass%, 20 mass%, 21 mass%, 22 mass%, 23 mass% %, 24% by mass, 25% by mass, 26% by mass, 27% by mass, 28% by mass, 29% by mass, 30.0% by mass, 35% by mass, 40% by mass, 45% by mass, 50% by mass, or 55% by mass, and The content of the polyglycolic acid homopolymer is 20% by mass to 99.9% by mass, preferably 45.0% by mass to 99.5% by mass, and more preferably 70.0% by mass to 99.0% by mass. For example, the content of the polyglycolic acid homopolymer is 25.0% by mass, 30.0% by mass, 35.0% by mass, 40.0% by mass, 45.0% by mass, 50.0% by mass, 55.0% by mass, 60.0% by mass, 65.0% by mass, 70.0% by mass, 71.0% by mass, 72.0% by mass, 73.0% by mass, 74.0% by mass, 75.0% by mass, 76.0% by mass, 77.0% by mass, 78.0% by mass, 79.0% by mass, 80.0% by mass, 81.0% by mass, 82.0% by mass, 83.0% by mass, 84.0% by mass, 85.0% by mass, 86.0% by mass, 87.0% by mass, 88.0% by mass, 89.0% by mass, 90.0% by mass, 91.0% by mass, 92.0% by mass, 93.0% by mass, 94.0% by mass, 95.0% by mass, 96.0% by mass, 97.0% by mass, 98.0% by mass, 99.0% by mass, 99.0% by mass, 10 ... .0% by mass, 75.0% by mass, 76.0% by mass, 77.0% by mass, 78.0% by mass, 79.0% by mass, 80.0% by mass, 81.0% by mass, 82.0% by mass, 83.0% by mass, 84.0% by mass, 85.0% by mass, 86.0% by mass, 87.0% by mass %, 88.0% by mass, 89.0% by mass, 90.0% by mass, 91.0% by mass, 92.0% by mass, 93.0% by mass, 94.0% by mass, 95.0% by mass, 96.0% by mass, 97.0% by mass, 98.0% by mass, or 99.0% by mass.

[0148] In the present invention, the molecular weight of the polyglycolic acid graft copolymer in the polyglycolic acid composition of the present invention is higher than the molecular weight of the polyglycolic acid homopolymer.

[0149] According to the present invention, a peak molecular weight M in the molecular weight distribution curve of more than 500,000 g / mol p (i.e., the lg(M w ) is greater than 5.7) the number of peaks is at least 1, e.g., 1, 2, or 3, and the peak molecular weight M is less than 500,000 g / mol p (i.e., the lg(M w The number of peaks where ) is less than 5.7 is at least 1, for example 1.

[0150] According to the present invention, the molecular weight distribution curve and the number of peaks in the molecular weight distribution curve can be measured by gel permeation chromatography (GPC). The peaks in the molecular weight distribution are those with a weight average molecular weight (M) of more than 10,000 g / mol. w ) (i.e., lg(M w )) is the point on the GPC curve where the first derivative is 0 and the second derivative is less than 0.

[0151] the overall weight average molecular weight / overall number average molecular weight of a polymer composition, such as a polyglycolic acid composition of the present invention; the overall molecular weight polydispersity index of a polymer composition, such as a polyglycolic acid composition; the number of peaks in the molecular weight distribution of a polymer composition, such as a polyglycolic acid composition; the weight average molecular weight / number average molecular weight of a polyester graft copolymer, such as a polyglycolic acid graft copolymer; the molecular weight polydispersity index of a polyester graft copolymer, such as a polyglycolic acid graft copolymer; Weight average molecular weight / number average molecular weight of polyester homopolymers such as polyglycolic acid homopolymers; the molecular weight polydispersity index of a polyester homopolymer, such as a polyglycolic acid homopolymer; a mass fraction of a polyester graft copolymer, such as a polyglycolic acid graft copolymer; a mass fraction of a polyester homopolymer, such as a polyglycolic acid homopolymer; etc. can be measured by gel permeation chromatography (GPC). Specific measurement methods are generally known in the art, and conventional test parameters may be used. For example, the following method may be used: the test equipment is a PL-GPC50 gel permeation chromatograph manufactured by Agilent Technologies, USA, the processing software is GPC offline, and during the test, the mobile phase is hexafluoroisopropanol containing 5 mmol / L sodium trifluoroacetate, the flow rate is 1 mL / min, the column temperature is 40°C, the injection volume is 100 μL, the standard sample is PMMA, and the sample concentration is 1 mg / mL. Specific values ​​of the above parameters are obtained according to analytical methods well known in the art.

[0152] The melt flow rate (MFR) of the polyglycolic acid composition of the present invention at 230°C / 2.16 kg is 20.0 g / 10 min or less, preferably 0.01 to 20.0 g / 10 min, more preferably 0.5 to 10.0 g / 10 min, for example, 0.5 g / 10 min, 1.0 g / 10 min, 2.0 g / 10 min, 3.0 g / 10 min, 4.0 g / 10 min, 5.0 g / 10 min, 6.0 g / 10 min, 7.0 g / 10 min, / 10 min, 8.0g / 10 min, 9.0g / 10 min, 10.0g / 10 min, 11.0g / 10 min, 12.0g / 10 min, 13.0g / 10 min, 14.0g / 10 min, 15.0g / 10 min, 16.0g / 10 min, 17.0g / 10 min, 18.0g / 10 min, 19.0g / 10 min, or 20.0g / 10 min, or may be a range formed by any two of the above values.

[0153] The melt flow rate can be measured by a method known in the art. For example, but not limited to, the MFR can be measured by the following method: using a CEAST MF20 melt flow rate tester manufactured by Instron Corporation, USA, the test temperature is 230°C, the load weight is 2.16 kg, and the preheating time is 4 minutes.

[0154] According to the present invention, the polyglycolic acid composition of the present invention has excellent melt strength. In some embodiments of the present invention, the melt strength of the polyglycolic acid composition at 235°C is 5 cN or more, preferably 8 cN or more, and 200 cN or less, preferably 100 cN or less.

[0155] The present invention also provides a method for preparing the polymer composition of the present invention, comprising melt polymerizing monomers for a polyester, a macromolecular initiator, and a small molecule initiator to provide the polymer composition. In some embodiments, the melt polymerization is carried out in the presence of a catalyst. In some other embodiments, the melt polymerization is carried out in the presence of a catalyst and an antioxidant.

[0156] In the method for preparing the polymer composition of the present invention, the monomer for the polyester may be selected from a hydroxy acid monomer or a derivative of a hydroxy acid monomer. In some embodiments, the monomer is selected from a lactide monomer, a lactone monomer, or a combination thereof. Preferably, the lactide monomer is an α-hydroxy acid or β-hydroxy acid-based lactide monomer, and more preferably, the lactide monomer is selected from the group consisting of glycolide, lactide, butyrolactone, valerolactone, caprolide, and any combination thereof. Preferably, the lactone monomer is selected from the group consisting of β-butyrolactone, δ-valerolactone, ε-caprolactone, β-propiolactone, β-valerolactone, γ-butyrolactone, γ-valerolactone, γ-octalactone, β-methyl-δ-valerolactone, δ-stearolactone, 2-methyl-ε-caprolactone, 4-methyl-ε-caprolactone, ε-octalactone, ε-palmitolactone, and any combination thereof; more preferably, the lactone monomer is selected from the group consisting of β-butyrolactone, δ-valerolactone, ε-caprolactone, and any combination thereof. Most preferably, the monomer is selected from the group consisting of methyl glycolate, glycolic acid, glycolide, and any combination thereof.

[0157] In the method for preparing the polymer composition of the present invention, the macroinitiator is at least one of polyvinyl alcohol and ethylene-vinyl alcohol copolymer.

[0158] As will be understood by one skilled in the art, in the method for preparing the polymer composition of the present invention, when the monomer for the polyester is selected from the group consisting of methyl glycolate, glycolic acid, glycolide, and any combination thereof, a polyglycolic acid composition of the present invention is prepared.

[0159] Therefore, the present invention provides a method for polymerizing a polyglycolic acid segment.

[0160] [ka]

[0161] The present invention provides a method for preparing a polyglycolic acid composition, comprising melt polymerizing a monomer capable of forming (I), a macromolecular initiator, and a small molecule initiator to obtain the polyglycolic acid composition. In some embodiments, the melt polymerization is carried out in the presence of a catalyst. In some other embodiments, the melt polymerization is carried out in the presence of a catalyst and an antioxidant. When used to obtain the polyglycolic acid composition, the monomer comprises at least one of methyl glycolate, glycolic acid, and glycolide, more preferably glycolide.

[0162] In the method of the present invention, the polyester graft copolymer, such as the polyglycolic acid graft copolymer, and the polyester homopolymer, such as the polyglycolic acid homopolymer, are simultaneously formed in situ during a melt polymerization process. As used herein, "simultaneously formed in situ" means that the polyester graft copolymer, such as the polyglycolic acid graft copolymer, and the polyester homopolymer, such as the polyglycolic acid homopolymer, are formed together in the same melt polymerization process.

[0163] In the ring-opening polymerization of cyclic ester monomers or lactide monomers such as glycolide, water can also be used as an initiator. Therefore, it is necessary to detect and, if necessary, control the water content of the cyclic ester monomers or lactide monomers such as glycolide to prevent the water content from becoming too high. When no additional low-molecular-weight initiator is added, the low-molecular-weight portion of the polymer composition, such as the polyglycolic acid composition, of the present invention is a polyester homopolymer, such as a polyglycolic acid homopolymer, obtained by using water in the raw materials, such as the monomers, as an initiator. Therefore, in some embodiments, a low-molecular-weight initiator is not intentionally added in the preparation method of the polymer composition of the present invention; rather, water in the raw materials, such as the monomers, is used as the low-molecular-weight initiator. In some embodiments, in the present invention, a monomer for a polyester, such as glycolide, may be directly used in the method for preparing the polymer composition of the present invention without the need for a separate, additional water removal treatment. Additionally, the method of the present invention is insensitive to water and therefore does not require an anhydrous operating environment, which is particularly advantageous.

[0164] In some embodiments, the water content in glycolide may be 0 ppm to 500 ppm or less, preferably 300 ppm or less, by weight, for example, 0 ppm, 10 ppm, 20 ppm, 30 ppm, 40 ppm, 50 ppm, 60 ppm, 70 ppm, 80 ppm, 90 ppm, 100 ppm, 150 ppm, 200 ppm, 250 ppm, 300 ppm, 350 ppm, 400 ppm, or 450 ppm. In some embodiments, the purity of glycolide may be 99.0 wt% or more, preferably 99.8 wt% or more, and may be up to 100 wt%. In some embodiments, the acid value of glycolide may be 0 mmol / kg to 5.0 mmol / kg or less, preferably 1.5 mmol / kg or less. In some embodiments, the present invention provides glycolide having a water content of 500 ppm or less, preferably 300 ppm or less, a purity of 99.0% or more, preferably 99.8% or more, and an acid value of 5.0 mmol / kg or less, preferably 1.5 mmol / kg or less.

[0165] According to the present invention, the macroinitiator is at least one of polyvinyl alcohol and ethylene-vinyl alcohol copolymer.

[0166] According to the present invention, the degree of alcoholysis of polyvinyl alcohol can be selected within a wide range. In some embodiments of the present invention, the degree of alcoholysis of the polyvinyl alcohol may be 68 to 99%, for example, 68%, 69%, 70%, 72%, 74%, 76%, 78%, 80%, 82%, 84%, 86%, 88%, 90%, 92%, 94%, 96%, or 98%. According to the present invention, the degree of polymerization of polyvinyl alcohol can be selected within a wide range. In some embodiments of the present invention, the degree of polymerization of the polyvinyl alcohol may be 100 to 6000, preferably 300 to 2000, for example, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000, or 5500, or may be a range formed by any two of the above values.

[0167] According to the present invention, the ethylene-vinyl alcohol copolymer can be selected within a wide range. In some embodiments of the present invention, the content of the ethylene segments in the ethylene-vinyl alcohol copolymer may be 25 to 50 mol%, for example, 25 mol%, 30 mol%, 35 mol%, 40 mol%, 45 mol%, or 50 mol%, or any range formed by any two of the above values. The degree of polymerization of the ethylene-vinyl alcohol copolymer may be 50 to 6000, preferably 300 to 2000, for example, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000, or 5500, or any range formed by any two of the above values.

[0168] According to the present invention, the melt flow rate of the ethylene-vinyl alcohol copolymer can be selected within a wide range. In some embodiments of the present invention, the melt flow rate of the ethylene-vinyl alcohol copolymer at 190°C / 2.16 kg may be 0.1 to 50.0 g / 10 min.

[0169] According to the present invention, the small molecule initiator can be selected from a wide range. In some embodiments of the present invention, the small molecule initiator may be water and / or a hydroxyl- and / or amino-group-containing small molecule compound having a boiling point above 160° C. and below 600° C. Preferably, the molecular weight of the hydroxyl and / or amino group-containing low molecular weight compound is more than 60 g / mol and not more than 1000 g / mol, preferably 60 to 300 g / mol. The low molecular weight initiator may be selected from water, ethylene glycol, butanediol, glycerol, serinol, leucinol, pentaerythritol, sorbitol, xylitol, amino acids, phenol, hydroquinone, resorcinol, benzyl alcohol, aniline, benzylamine, p-phenylenediamine, m-phenylenediamine, hexamethylenediamine, dodecanediamine, etc.

[0170] In the present invention, the content of hydroxyl, calculated as hydroxyl and contained in the polymeric initiator for each gram of monomer, may be 0.1 μmol / g monomer to 1.5 mmol / g monomer, preferably 0.5 μmol / g monomer to 1.0 mmol / g monomer, more preferably 1.0 μmol / g monomer to 0.5 mmol / g monomer; and / or In the present invention, the content of active hydrogen calculated as active hydrogen and contained in the low molecular weight initiator for each gram of monomer may be 3.0 μmol / g monomer to 40.0 μmol / g monomer, preferably 10.0 μmol / g monomer to 30.0 μmol / g monomer.

[0171] In some embodiments, the hydroxyl content, calculated as hydroxyl and per gram of monomer contained in the macroinitiator, may be from 0.1 μmol / g monomer to 1.5 mmol / g monomer, preferably from 0.5 μmol / g monomer to 1.0 mmol / g monomer, and more preferably from 1.0 μmol / g monomer to 0.5 mmol / g monomer. In some embodiments, the hydroxyl content, calculated as hydroxyl and per gram of monomer contained in the macroinitiator, may be from 0.1 μmol / g monomer, 0.2 μmol / g monomer, 0.3 μmol / g monomer, 0.4 μmol / g monomer, 0.5 μmol / g monomer, 0.6 μmol / g monomer, or 0.7 μmol / g monomer, up to 0.85 mmol / g monomer, 0.90 mmol / g monomer, 0.95 mmol / g monomer, or 1.0 mmol / g monomer.

[0172] In some embodiments, the content of active hydrogen contained in the low molecular weight initiator, calculated as active hydrogen and relative to each gram of monomer, may be 3.0 μmol / g monomer to 40.0 μmol / g monomer, preferably 10.0 μmol / g monomer to 30.0 μmol / g monomer. In some embodiments, the content of active hydrogen, calculated as active hydrogen and contained in the small molecule initiator for each gram of monomer, is 3.0 μmol / g monomer, 4.0 μmol / g monomer, 5.0 μmol / g monomer, 6.0 μmol / g monomer, 7.0 μmol / g monomer, 8.0 μmol / g monomer, 9.0 μmol / g monomer, 10.0 μmol / g monomer, 11.0 μmol / g monomer, 12.0 μmol / g monomer, 13.0 μmol / g monomer, 14.0 μmol / g monomer, 15.0 μmol / g monomer, 16.0 μmol / g monomer, 17.0 μmol / g monomer, 18.0 μmol / g monomer, 19.0 μmol / g monomer. mer, 20.0 μmol / g monomer, 21.0 μmol / g monomer, 22.0 μmol / g monomer, 23.0 μmol / g monomer, 24.0 μmol / g monomer, 25.0 μmol / g monomer, 25.5 μmol / g monomer, 26.0 μmol / g monomer, 26.5 μmol / g monomer, 27.0 μmol / g monomer, 27.5 μmol / g monomer, 28.0 μmol / g monomer, 29.0 μmol / g monomer, 30.0 μmol / g monomer, 31.0 μmol / g monomer, 32.0 μmol / g monomer, 33.0 μmol / g monomer, 34.0 μmol / g monomer, 35.0 μmol / g monomer, or 40.0 μmol / g monomer.

[0173] According to the present invention, the catalyst can be selected from a wide range. In some embodiments of the present invention, the catalyst may be at least one salt compound of a metal element of Group IIA to Group VA and a transition metal element, or an organic guanidine catalyst. Preferably, the catalyst is at least one salt compound of Sn, Bi, Mg, Al, Ca, Fe, Mn, Ti, and Zn, and more preferably a Sn salt.

[0174] According to the present invention, the antioxidant can be selected within a wide range. In some embodiments of the present invention, the antioxidant is selected from the group consisting of hindered phenolic antioxidants and / or phosphite antioxidants, i.e., hindered phenolic antioxidants, phosphite antioxidants, and any combination thereof.The antioxidants include, but are not limited to, 2,6-di-tert-butyl-p-cresol, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 2,2'-methylenebis(6-tert-butyl-4-methylphenol), hexanediol bis[β-(3,5-dibutyl-4-hydroxyphenyl)propionate], antioxidant Irganox® from BASF, Pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (such as Antioxidant 1010), N,N'-bis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine (such as Antioxidant 1024), N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexanediamine (such as Antioxidant 1098), Irganox 1010 (antioxidant from BASF), N,N'-bis-(β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexanediamine (such as Antioxidant 1098 ... 1076) n-Octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 1,3,5-trimethyl-2,4,6-tri(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, triphenyl phosphite, tri(4-nonylphenyl)phosphite, diphenyl isooctyl phosphite, diphenyl isodecyl phosphite, monophenyl di(2-ethylhexyl) phosphite, phenyl diisodecyl phosphite, tri(2-ethylhexyl) The antioxidant may comprise at least one of tris[2,4-di-tert-butylphenyl]phosphite, triisodecyl phosphite, tri(dodecyl) phosphite, pentaerythritol diisodecyl diphosphite, tris[2,4-di-tert-butylphenyl]phosphite (such as Antioxidant 168), bis(2,4-dicumylphenyl)pentaerythritol diphosphite (such as Antioxidant 686), and bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite (such as Antioxidant 626).

[0175] According to the present invention, the amount of antioxidant used can be selected within a wide range. In some embodiments of the present invention, the amount of antioxidant used may be 0 to 2 parts, preferably 0.01 to 1 part (phr), based on 100 parts by weight of the monomer.

[0176] According to the present invention, the amount of polyvinyl alcohol and / or ethylene-vinyl alcohol copolymer used can be selected within a wide range. In some embodiments of the present invention, when polyvinyl alcohol is used, the amount of polyvinyl alcohol used may be 0.001 to 5 parts by mass, preferably 0.005 to 3 parts by mass, preferably 0.005 to 1 part by mass, more preferably 0.01 to 1 part by mass, per 100 parts by mass of monomer. In some embodiments, the amount of polyvinyl alcohol used, by weight, per 100 parts by weight of monomer is 0.001 parts, 0.002 parts, 0.003 parts, 0.004 parts, 0.005 parts, 0.006 parts, 0.007 parts, 0.008 parts, 0.009 parts, 0.010 parts, 0.011 parts, 0.012 parts, 0.013 parts, 0.014 parts, 0.015 parts, 0.016 parts, 0.017 parts, 0.018 parts, 0.019 parts, 0.020 parts, 0.021 parts, 0.022 parts, 0.023 parts, 0.024 parts, 0.025 parts, 0.026 parts, 0.027 parts, 0.028 parts, 0.029 parts, 0.030 parts, 0.031 parts, 0.032 parts, 0.033 parts, 0.034 parts, 0.035 parts, 0.036 parts, 0.037 parts, 0.038 parts, 0.039 parts, 0.040 parts, 0.041 parts, 0.042 parts, 0.043 parts, 0.044 parts, 0.045 parts, 0.046 parts, 0.047 parts, 0.048 parts, 0.049 parts, 0.050 parts, 0.051 parts, 0.052 parts, 0.053 parts, 0.054 parts, 0.055 parts, 0.056 parts, 0.057 parts, 0.058 parts, 0.059 parts, 0.060 parts, 0.0 0.027 parts, 0.028 parts, 0.029 parts, 0.030 parts, 0.035 parts, 0.040 parts, 0.050 parts, 0.060 parts, 0.070 parts, 0.080 parts, 0.090 parts, 0.10 parts, 0.11 parts, 0.12 parts, 0.13 parts, 0.14 parts, 0.15 parts, 0.16 parts, 0.17 parts, 0.18 parts, 0.19 parts, 0.20 parts, 0.30 parts, 0.40 parts, 0.50 parts, 0.60 parts, 0.70 parts, 0.80 parts, 0.90 parts, 1.0 parts, 1.5 parts, 2.0 parts, 2.5 parts, 3.0 parts, 3.5 parts, 4.0 parts, 4.5 parts, or 5.0 parts.

[0177] In some embodiments of the present invention, when the ethylene-vinyl alcohol copolymer is used, the amount of the ethylene-vinyl alcohol copolymer used may be 0.001 to 10 parts by mass, preferably 0.002 to 8 parts by mass, preferably 0.005 to 7 parts by mass, and more preferably 0.01 to 5 parts by mass, relative to 100 parts by mass of the monomer. In some embodiments, the amount of the ethylene-vinyl alcohol copolymer used, by weight, per 100 parts by weight of the monomers is 0.001 parts, 0.002 parts, 0.003 parts, 0.004 parts, 0.005 parts, 0.006 parts, 0.007 parts, 0.008 parts, 0.009 parts, 0.010 parts, 0.011 parts, 0.012 parts, 0.013 parts, 0.014 parts, 0.015 parts, 0.016 parts, 0.017 parts, 0.018 parts, 0.019 parts, 0.020 parts, 0.021 parts, 0.022 parts, 0.023 parts, 0.024 parts, 0.025 parts, 0.026 parts, 0.027 parts, 0.028 parts, 0.029 parts, 0.030 parts, 0.031 parts, 0.032 parts, 0.033 parts, 0.034 parts, 0.035 parts, 0.036 parts, 0.037 parts, 0.038 parts, 0.039 parts, 0.040 parts, 0.041 parts, 0.042 parts, 0.043 parts, 0.044 parts, 0.045 parts, 0.046 parts, 0.047 parts, 0.048 parts, 0.049 parts, 0.050 parts, 0.051 parts, 0.052 parts, 0.053 parts, 0.054 parts, 0.055 parts, 0.056 parts, 0.057 parts, 0.058 parts, 0.059 parts, 0.060 28 copies, 0.029 copies, 0.030 copies, 0.035 copies, 0.040 copies, 0.050 copies, 0.060 copies, 0.070 copies, 0.080 copies, 0.09 0 parts, 0.10 parts, 0.11 parts, 0.12 parts, 0.13 parts, 0.14 parts, 0.15 parts, 0.16 parts, 0.17 parts, 0.18 parts, 0.19 parts, 0 It may be 0.20 parts, 0.30 parts, 0.40 parts, 0.50 parts, 0.60 parts, 0.70 parts, 0.80 parts, 0.90 parts, 1.0 parts, 1.5 parts, 2.0 parts, 2.5 parts, 3.0 parts, 3.5 parts, 4.0 parts, 4.5 parts, 5.0 parts, 6.0 parts, 7.0 parts, 8.0 parts, 9.0 parts, or 10.0 parts.

[0178] According to the present invention, the amount of the low molecular weight initiator used can be selected within a wide range. In some embodiments of the present invention, the amount of the low molecular weight initiator used is 0.001 to 1 part, preferably 0.01 to 0.1 parts, per 100 parts by weight of the monomer. In some embodiments, the amount of the low molecular weight initiator used is 0.001 parts, 0.002 parts, 0.003 parts, 0.004 parts, 0.005 parts, 0.006 parts, 0.007 parts, 0.008 parts, 0.009 parts, 0.010 parts, 0.011 parts, 0.012 parts, 0.013 parts, 0.014 parts, 0.015 parts, 0.016 parts, 0.017 parts, 0.018 parts, 0.019 parts, 0.020 parts, 0.021 parts, 0.022 parts, 0.023 parts, 0.024 parts, 0.025 parts, 0.026 parts, 0.027 parts, 0.028 parts, 0.029 parts, 0.030 parts, 0.031 parts, 0.032 parts, 0.033 parts, 0.034 parts, 0.035 parts, 0.036 parts, 0.037 parts, 0.038 parts, 0.039 parts, 0.040 parts, 0.041 parts, 0.042 parts, 0.043 parts, 0.044 parts, 0.045 parts, 0.046 parts, 0.047 parts, 0.048 parts, 0.049 parts, 0.050 parts, 0.051 parts, 0.052 parts, 0.0 018 parts, 0.019 parts, 0.020 parts, 0.021 parts, 0.022 parts, 0.023 parts, 0.024 parts, 0.025 parts, 0.026 parts, 0.027 parts, 0.028 parts, 0.029 parts, 0. 030 copies, 0.031 copies, 0.032 copies, 0.033 copies, 0.034 copies, 0.035 copies, 0.036 copies, 0.037 copies, 0.038 copies, 0.039 copies, 0.040 copies, 0.041 copies, 0.0 42 copies, 0.043 copies, 0.044 copies, 0.045 copies, 0.046 copies, 0.047 copies, 0.048 copies, 0.049 copies, 0.050 copies, 0.051 copies, 0.052 copies, 0.053 copies, 0.0 54 copies, 0.055 copies, 0.056 copies, 0.057 copies, 0.058 copies, 0.059 copies, 0.060 copies, 0.061 copies, 0.062 copies, 0.063 copies, 0.064 copies, 0.065 copies, 0.0 0.66 parts, 0.067 parts, 0.068 parts, 0.069 parts, 0.070 parts, 0.080 parts, 0.090 parts, 0.10 parts, 0.11 parts, 0.12 parts, 0.13 parts, 0.14 parts, 0.15 parts, 0.16 parts, 0.17 parts, 0.18 parts, 0.19 parts, 0.20 parts, 0.30 parts, 0.40 parts, 0.50 parts, 0.60 parts, 0.70 parts, 0.80 parts, 0.90 parts, or 1.0 part.

[0179] According to the present invention, the amount of catalyst used can be selected within a wide range. In some embodiments of the present invention, the amount of catalyst used is 0.005 to 1 part, preferably 0.01 to 0.2 parts by mass, per 100 parts of monomer.

[0180] According to the present invention, the melt polymerization reaction conditions can be selected within a wide range. In some embodiments of the present invention, the melt polymerization conditions are: a temperature of 120 to 300°C, preferably 160 to 250°C, and more preferably 200 to 240°C; Includes:

[0181] According to the present invention, the time conditions for melt polymerization can be selected within a wide range. In some embodiments of the present invention, the reaction time is 0.5 to 60 minutes, preferably 1 to 10 minutes.

[0182] In some preferred embodiments of the present invention, the temperature of the melt polymerization reaction is 120 to 300°C, preferably 160 to 250°C, and more preferably 200 to 240°C, and the reaction time is 0.5 to 60 minutes, preferably 1 to 10 minutes.

[0183] The melt polymerization reaction may be carried out in a melt mixing device, preferably comprising one or more of a kettle reactor, a tubular reactor, an internal mixer, a Farrel continuous mixer, a Banbury mixer, a single screw extruder such as a reciprocating single screw extruder, and a multi-screw extruder such as a twin screw extruder, and for example, a combination of multiple types of devices or multiple devices in series, preferably an internal mixer or a twin screw extruder, may also be used.

[0184] In some embodiments of the present invention, the melt polymerization is carried out in a twin-screw extrusion system. Preferably, the polymerization reaction conditions in the twin-screw extrusion system are: a temperature of 180 to 250°C, preferably 210 to 240°C; and / or a screw rotation speed of 5 to 300 rpm, preferably 40 to 150 rpm; and / or a length-to-diameter ratio of 25 to 80, preferably 40 to 70; In some embodiments, the twin screw extrusion system is a continuous twin screw extrusion system.

[0185] In some embodiments, the melt polymerization reaction may be carried out in at least two, e.g., two, three, or four, twin-screw extrusion systems connected in series. Preferably, the polymerization reaction conditions in each twin-screw extrusion system connected in series are: a temperature of 180 to 250°C, preferably 210 to 240°C; and / or a screw rotation speed of 5 to 300 rpm, preferably 40 to 150 rpm; and / or a length-to-diameter ratio of 25 to 80, preferably 40 to 70; Includes:

[0186] According to the present invention, connecting twin-screw extrusion equipment in series can provide beneficial effects. Connecting twin-screw extrusion equipment in series can increase the length-to-diameter ratio, thereby extending the residence time of the material in the twin-screw extrusion equipment (i.e., increasing the reaction time), thereby reducing the reaction temperature or further increasing the reaction conversion rate. In addition, vacuum devolatilization treatment can be performed in the subsequent series-connected equipment to reduce the content of one or more unreacted residual monomers, and / or metal deactivators can be added to reduce the impact of the catalyst on product stability.

[0187] In some embodiments of the present invention, the melt polymerization is carried out in an internal mixer, in which the internal mixing temperature is 180 to 250°C, preferably 200 to 230°C, the rotation speed is 5 to 150 rpm, preferably 20 to 80 rpm, and the reaction time is 1 to 20 minutes, preferably 3 to 10 minutes.

[0188] Internal mixer equipment suitable for the present invention may include internal mixers of various designs, such as the PolyLab HAAKE® Rheomex OS 567-1000 Internal Mixer Module manufactured by Thermo Fisher Scientific, USA.

[0189] Twin screw extrusion equipment suitable for the present invention may include twin screw extruders of various designs, such as the HAAKE Eurolab 16 benchtop parallel co-rotating twin screw extruder manufactured by Thermo Fisher Scientific, USA, and the ZSK Mc18 or ZSK 40 co-rotating parallel twin screw extruders manufactured by Coperion, Germany. In some embodiments, a LabTech parallel co-rotating twin screw extruder may be used.

[0190] The present invention also provides a polymer composition, such as a polyglycolic acid composition, prepared by the preparation method of the present invention. The preparation method of the present invention can prepare a polymer composition, such as a polyglycolic acid composition of the present invention.

[0191] The polyglycolic acid composition of the present invention has the characteristics of high molecular weight and multimodal molecular weight distribution, significantly improving the melt strength of the polyglycolic acid composition while maintaining sufficient processability. At the same time, the method for preparing the polyglycolic acid composition of the present invention has high production efficiency, can achieve continuous preparation in a twin-screw extruder, and significantly reduces the reaction time. The reaction time is shortened from several hours in the prior art to just a few minutes, significantly saving energy consumption and reducing carbon emissions, and overcoming the drawbacks of high production costs and energy consumption caused by the slow polymerization reaction of polyglycolic acid in the prior art.

[0192] The present invention also provides articles comprising a polymeric composition, such as the polyglycolic acid composition of the present invention, which may be selected from the group consisting of a film, a rod, a tube, a wire, a sheet, a profile, and any combination thereof.

[0193] In some embodiments, the article of the present invention is a film, preferably a multilayer composite film, comprising a polymer composition, such as a polyglycolic acid composition of the present invention. Preferably, the film, such as a multilayer composite film, comprises the polyglycolic acid composition of the present invention, such that the polyglycolic acid composition of the present invention is included in at least one layer.

[0194] In some embodiments, the present invention provides a coating composition comprising a barrier layer, a protective layer, and a tie layer; the protective layer is an outer layer; the tie layer is located between the barrier layer and the protective layer; and the barrier layer contains the polyglycolic acid composition of the present invention. A multilayer composite film having high barrier properties is provided.

[0195] According to the present invention, the number of barrier layers may be at least 1, for example, 1, 2, or 3 layers. The thickness of a single barrier layer may be 1 to 50 microns. The number of protective layers may be at least 2, for example, 2 to 7. The material of each protective layer may be the same or different, and the thickness of each layer may be 3 to 80 microns. The outermost layer of the multilayer composite film must be a protective layer. The number of tie layers may be at least 2, and the thickness of a single layer may be 0.5 to 20 microns. In some embodiments, the total thickness of the multilayer composite film may be 8 to 250 microns.

[0196] According to the present invention, the protective layer may comprise a polyolefin having good water barrier properties and good toughness. Preferably, the polyolefin may be selected from the group consisting of low density polyethylene, linear low density polyethylene, medium density polyethylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, polypropylene, ethylene-propylene-diene-non-conjugated diene copolymer, metallocene polyethylene, metallocene polypropylene, poly-1-butene and its derivatives, cycloolefin polymer (COP), and any combination thereof.

[0197] According to the present invention, the tie layer may be a polyolefin graft copolymer or an ethylene-polar monomer copolymer. Preferably, the polyolefin graft copolymer may be selected from the group consisting of maleic anhydride grafted polyethylene, acrylic acid grafted polyethylene, methyl methacrylate grafted polyethylene, maleic anhydride grafted polypropylene, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, and any combination thereof.

[0198] According to the present invention, in some embodiments, the oxygen transmission rate (OTR) of the multilayer composite film at 23±0.5° C. and 65%±5% relative humidity is 100 cm 3 / (m 2 ·day·atm) or less, preferably 30cm 3 / (m 2 ·day·atm).

[0199] According to the present invention, in some embodiments, the multilayer composite film has a water vapor transmission rate (WVTR) of 30 g / (m) or less at 38±0.5° C., 90%±5% relative humidity, and 1 standard atmosphere pressure. 2 ·day·atm) or less, preferably 15g / (m 2 ·day·atm).

[0200] According to the present invention, the heat seal strength of the multilayer composite film is 3N / 15mm or more, preferably 5N / 15mm or more.

[0201] According to the present invention, the interlayer peel strength of the multilayer composite film is 0.5 N / 15 mm or more, preferably 1.5 N / 15 mm or more.

[0202] The present invention also provides a method for producing the multilayer composite film of the present invention. In some embodiments, the method includes adding a polymer composition such as the polyglycolic acid composition of the present invention, a polyolefin, and a polyolefin graft copolymer to a screw extruder, melting, compressing, and extruding each of them, then forming them into films separately through a casting die or a film blowing die, and then combining the film layers into a multilayer composite film by hot pressing. In some other embodiments, the method includes adding a polymer composition such as the polyglycolic acid composition, a polyolefin, and a polyolefin graft copolymer to different screw extruders, melting and compressing each of them, then extruding them through a coextrusion distributor and a film forming die, cooling, and winding to obtain a multilayer composite film. Preferably, the film product is stretched through a uniaxial stretching unit before being wound up.

[0203] The preparation of multilayer composite films is known in the art. In the present invention, the multilayer composite film of the present invention can be prepared by using a preparation method generally known in the art.

[0204] In some preferred embodiments, the films of the present invention are made by a film blowing process.

[0205] According to the present invention, the screw extruder may be a single screw extruder or a twin screw extruder, and the film-forming die may be a film blowing die or a film casting die.

[0206] In some embodiments of the present invention, the film-forming die is a film-blowing die, and the blowing ratio during film-blowing is (1-6):1, preferably (2-5):1.

[0207] Single screw extrusion film blowing machines applicable to the present invention include various designs of film blowing machines, such as the single screw extrusion film blowing machine model E30P manufactured by Dr. Collin, Germany.

[0208] In some embodiments, films may be formed by a film-blowing process in which a gas (e.g., air) is used to expand a film bubble formed by extruding a polymer through an annular die. The blow-up ratio and film thickness can be controlled by adjusting the gas pressure in the film bubble; the greater the pressure, the larger the film bubble, the thinner the film, and the higher the degree of orientation in the transverse direction of the film. The film bubble (such as 01a in Figure 4) is then flattened by the two rollers described above, cut into two flat films, and wound up. The faster the winding speed, the higher the longitudinal tensile orientation and the corresponding decrease in film thickness.

[0209] According to the present invention, the production process includes a uniaxial stretching unit before the winding process. Whether the film is produced by film blowing or film casting, the film may be optionally oriented in one or more directions before the winding process to further increase the film's orientation and reduce its thickness. For example, the film may be heated by a guide roller heating process to a temperature below the melting point (above the glass transition temperature) of one or more polymers in the film, but high enough to allow the composition to be continuously and controllably stretched. The heated and "softened" film is gradually stretched by guide rollers rotating at different speeds, resulting in a desired stretch ratio in the machine direction (MD). This "uniaxially" oriented film may then be stretched and wound up.

[0210] FIG. 4 illustrates a method for forming a uniaxially oriented film. As shown in FIG. 4, the blown film 01b is introduced into a uniaxial stretching unit 80 (e.g., an MDO unit, commercially available from Marshall and Williams, Inc., Providence, RI). The MDO unit has multiple stretching rollers (e.g., 5-8) to gradually stretch and thin the film in the MD direction, which is the direction the film travels through the process, as shown in the figure. While the MDO unit 80 shown in FIGS. 4 and 5 has seven rollers, it should be understood that the number of rollers may be greater or less depending on the desired stretch ratio and the degree of stretch between each roller. The film may be stretched in a single stretching unit or in multiple stretching units connected in series. It should be noted that some guide rollers in an MDO apparatus may operate at any speed. If desired, some guide rollers in an MDO may be used as preheat rollers. If present, these first several rollers heat the film 01b above the minimum glass transition temperature of the polymer (e.g., 50°C). Gradually increasing the speed of adjacent rollers within the MDO serves to stretch the film 01b. The rotational speed of the stretching rollers determines the amount of stretching of the film and the final film thickness. The resulting film 01c may then be wound onto take-up roller 90 and collected.

[0211] Although not shown herein, the film may be processed using a variety of additional potential processing and / or finishing steps known in the art, such as slitting, treating, perforating, printing graphics, or laminating, without departing from the spirit and scope of the present invention.

[0212] In some embodiments of the present invention, the rotation speed of the screw extruder may be 10 to 200 rpm, and / or the extrusion temperature may be 180° C. to 260° C. In some embodiments, the ratio of the diameter of the blown film bubble to the diameter of the blown film machine die (blow-up ratio) may be 1:1 to 6:1, preferably 2:1 to 5:1.

[0213] In some embodiments of the present invention, the method of fabrication further comprises preparing a polymer composition, such as a polyglycolic acid composition. For example, the polyglycolic acid composition may be prepared as described hereinabove, and the resulting polyglycolic acid composition is then used to fabricate the film of the present invention.

[0214] Multilayer composite films comprising the polyglycolic acid composition of the present invention can be used in a variety of applications, including, but not limited to, degradable packaging bags, pharmaceutical packaging films, food packaging films, agricultural films, barrier containers, and the like.

[0215] The multilayer composite film of the present invention has excellent gas barrier properties and good overall mechanical properties and processability while maintaining excellent biodegradability. The composite film of the present invention has a heat seal strength of 3 N / 15 mm or more, an interlayer peel strength of 0.5 N / 15 mm or more, and an oxygen permeability and a water vapor permeability of 100 cm or more. 3 / (m 2 ·day·atm) or less and 30g / (m 2 In addition, the film production method of the present invention is simple, requires little equipment, has high production efficiency, can produce a composite film with a relatively small thickness, and has low overall production costs.

[0216] The barrier performance of the films of the present invention is far superior to films of other barrier materials or films of polyglycolic acid blends using conventional polyglycolic acid as the discontinuous phase.

[0217] The range endpoints and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the range endpoints, range endpoints and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, and should be considered specifically disclosed herein.

[0218] [Example] The present invention will be described in detail below with reference to specific examples.It should be noted that the following examples are only used to further illustrate the present invention and should not be construed as limiting the protection scope of the present invention.Based on the content of the present invention, some non-essential improvements and adjustments made to the present invention by those skilled in the art still fall within the protection scope of the present invention.

[0219] <Raw materials> All of the raw materials used in the present invention are commercially available.

[0220] Glycolide was purchased from Shenzhen Boli Biomaterials Co., Ltd. and had a purity of ≥99.5%, a water content of ≤500 ppm, and an acid value of ≤3 mmol / kg.

[0221] Anhydrous stannous chloride, stannous octoate, 1,4-butanediol (BDO), and serinol were all purchased from Sinopharm Group Chemical Reagents Co., Ltd. The purity of anhydrous stannous chloride, stannous octoate, and serinol was AR grade, and the purity of 1,4-butanediol was CP grade.

[0222] Antioxidant 1010 was purchased from BASF (China) Co., Ltd., and antioxidant 626 was purchased from Shanghai McKinney Biochemical Technology Co., Ltd., with a purity of 95% or more.

[0223] Polyvinyl alcohol (PVA) was purchased from Chongqing Chuanwei Chemical Co., Ltd. of China Petrochemical Group, and had an item number of 0588, a degree of polymerization of about 500, and an alcoholysis degree of about 88%.

[0224] Ethylene-vinyl alcohol copolymer (EVOH) was purchased from Kuraray Co., Ltd., Japan, under the trade name EVAL® H171B, with an ethylene content of 38 mol%, a melt flow rate of 1.7 g / 10 min at 190°C / 2.16 kg, a number average molecular weight of approximately 18,000 g / mol, a total degree of polymerization of approximately 480, and a hydroxyl content of approximately 0.01 mol / g EVOH.

[0225] Polyglycolide (PGA) was purchased from Corbion PURAC, The Netherlands, and is a GMP-grade glycolide homopolymer with an average intrinsic viscosity of 1.2 dl / g.

[0226] In the present invention, measurements were carried out according to the following method.

[0227] <Melt flow rate measurement> The test was carried out using a CEAST MF20 melt flow rate tester manufactured by Instron, USA. The test temperature was 230°C, the load weight was 2.16 kg, and the preheating time was 4 minutes.

[0228] <Gel Permeation Chromatography (GPC)> The test equipment was a PL-GPC50 gel permeation chromatograph manufactured by Agilent Technologies, USA, and the processing software was GPC offline. During the test, the mobile phase was hexafluoroisopropanol containing 5 mmol / L sodium trifluoroacetate, the flow rate was 1 mL / min, the column temperature was 40°C, the injection volume was 100 μL, the standard sample was PMMA, and the sample concentration was 1 mg / mL.

[0229] <Injection molding method and tensile test> The samples were injection molded into 5A tensile specimens (thickness: 2 mm) using a HAAKE MiniJet micro-injection molding machine in accordance with GB / T1040.2-2006. The barrel and die temperatures were 240°C and 50°C, respectively, the injection pressure and time were 400 bar and 5 seconds, respectively, and the support pressure and time were 100 bar and 10 seconds, respectively. Tensile tests were then performed using an Instron 3344 material testing machine (USA) at a tensile speed of 50 mm / min and a clamp spacing of 50 mm.

[0230] <Melt strength test> The test was performed using a Rosand RH7 high-pressure capillary rheometer manufactured by Malvern Panalytical Co., Ltd., China, with a Haul Off die model (diameter: 2.0 mm, length: 20 mm). The barrel pusher speed was 15 mm / min, the test temperature was 235°C, the initial take-up speed of the take-up roller was 3 m / min, and the final take-up speed was 50 m / min. The speed was increased at a uniform rate, and the speed increase time was 3 minutes. 30 data points were collected evenly.

[0231] <Testing the thickness of each layer of a multilayer film> The multilayer film was imaged using a KH-1300M 3D video microscope manufactured by Hirox Corporation, Japan. The film was fixed in place using a homemade film fixture, cut with a blade, and the cross section was observed at 400x magnification. The thickness was measured using the built-in measurement tool in the software.

[0232] <Interlayer peel strength test> According to Method A in GB8808-1988, the multilayer film was cut into strips with a width of 15 mm and a length of 200 mm. After peeling off a portion of the film by 50 mm, a tensile test was performed using an Instron Model 3344 material testing machine manufactured by the US company. The unpeeled portion was T-shaped in the tensile direction, and the tensile speed was 300 mm / min.

[0233] <Heat seal strength> Referring to QB / T2358-1998, the sample width was 15 mm, the clamp spacing was 50 mm, and the test speed was 300 mm / min.

[0234] <Oxygen barrier performance test> Measurements were performed using a MOCON OX-TRAN 2 / 22 oxygen transmission rate tester. Film samples were cut using a circular sampler and the thickness was measured in accordance with the international standard ISO 15105-2. A high-vacuum sealant was applied along the sealing ring on one side of the sample, and the sample was fixed in the test cabinet. The test temperature was 23°C and the relative humidity (RH) was 65%.

[0235] <Water vapor barrier performance test> Measurements were performed using a MOCON PERMATRAN-W 3 / 61 model water vapor transmission rate tester. Film samples were tested for water vapor barrier performance by the infrared detector method in accordance with the international standard ISO 15106-2. Circular film samples were sampled with a sampler and measured for thickness. The test temperature was 38°C, the relative humidity was 90%, the pressure was 1 standard atmosphere (atm), and the test time was 24 hours.

[0236] <Characterization of microscopic surface morphology> The samples were hot-pressed into thin sheets at 240 °C, immersed in liquid nitrogen, and then quenched at low temperatures to fracture, after which gold was plated on the surface. The cross sections were photographed using a MERLIN field emission scanning electron microscope (ZEISS, Germany).

[0237] Example 1 Glycolide (water content 260 ppm), stannous octoate, polyvinyl alcohol (PVA), 1,4-butanediol (BDO), antioxidant 1010, and antioxidant 626 were homogeneously mixed in a mass ratio of 100:0.1:0.015:0.035:0.5:0.3 and then extruded and pelletized using a LabTech parallel co-rotating twin-screw extruder (screw diameter: 20 mm, length-to-diameter ratio: 40). The extruder had 11 sections, numbered 1 through 11, from the feed throat to the die. Section 1 served only to feed the materials and was not heated. The temperatures of sections 2 through 11 of the extruder were 160°C, 200°C, 220°C, 220°C, 220°C, 220°C, 220°C, 230°C, 235°C, and 240°C, respectively. The feed rate was 3 kg / h, the screw rotation speed was 150 rpm, and the average residence time was approximately 3 minutes. The hydroxyl content of the PVA in the raw material was 2.69 μmol / g glycolide, and the active hydrogen content of the low molecular weight initiator was 22.22 μmol / g glycolide. According to formula (b) in the specification, the degree of polymerization p of polyglycolic acid in the graft copolymer was greater than 44.

[0238] <Example 2> The synthesis method was the same as that in Example 1, except that the polymer initiator was changed to ethylene-vinyl alcohol copolymer (EVOH) and the ratio of glycolide (water content 210 ppm), stannous octoate, EVOH, 1,4-butanediol (BDO), antioxidant 1010, and antioxidant 626 was set to 100:0.1:0.02:0.04:0.5:0.5. The temperature was changed to 160°C, 200°C, 220°C, 220°C, 220°C, 220°C, 220°C, 220°C, 220°C, and 220°C. The hydroxyl content derived from the EVOH in the raw material was 3.28 μmol / g glycolide, and the active hydrogen content in the low molecular weight initiator in the raw material was 20.56 μmol / g glycolide. According to formula (b) in the specification, the degree of polymerization p of the polyglycolic acid in the graft copolymer was greater than 190.

[0239] Example 3 The synthesis method was the same as that of Example 1, except that the amount of PVA was adjusted to 0.05 phr, 1,4-butanediol (BDO) was not added, and the amount of antioxidant was slightly adjusted; that is, the mass ratio of glycolide (water content 180 ppm) and antioxidant 626 was changed to 100:0.5. The hydroxyl content derived from PVA in the raw material was 8.95 μmol / g glycolide, and the active hydrogen content in the low molecular weight initiator in the raw material was 10.00 μmol / g glycolide. According to formula (b) in the specification, the degree of polymerization p of polyglycolic acid in the graft copolymer was greater than 83.

[0240] Example 4 The synthesis method was the same as that of Example 2, except that the equipment was changed to a Eurolab parallel co-rotating twin-screw extruder (screw diameter: 16 mm, length to diameter ratio: 40), the water content of glycolide was 240 ppm, the amount of catalyst was changed to 0.03 phr anhydrous stannous chloride, the amount of ethylene-vinyl alcohol copolymer (EVOH) was changed to 1 part by mass (phr), 1,4-butanediol was not added, the screw rotation speed was changed to 100 rpm, the temperatures were changed to 120°C, 180°C, 230°C, 230°C, 230°C, 230°C, 230°C, 230°C, 230°C, 230°C, 210°C, the feed rate was changed to 1 kg / h, and the average residence time was about 6 minutes. The hydroxyl content derived from EVOH in the raw material was 0.164 mmol / g glycolide, and the active hydrogen content in the low molecular weight initiator in the raw material was 13.33 μmol / g glycolide. According to formula (b) in the specification, the degree of polymerization p of polyglycolic acid in the graft copolymer was greater than 292.

[0241] <Example 5> The synthesis method was the same as that of Example 4, except that the amount of ethylene-vinyl alcohol copolymer (EVOH) was changed to 3 phr. The hydroxyl content of the EVOH in the raw material was 0.492 mmol / g glycolide, and the active hydrogen content of the low molecular weight initiator in the raw material was 13.33 μmol / g glycolide. According to formula (b) in the specification, the degree of polymerization p of polyglycolic acid in the graft copolymer was greater than 67.

[0242] Example 6 The synthesis method was the same as that of Example 4, except that the amount of ethylene-vinyl alcohol copolymer (EVOH) was changed to 5 phr, the screw rotation speed was changed to 50 rpm, and the average residence time was about 7 minutes. The hydroxyl content derived from EVOH in the raw material was 0.82 mmol / g glycolide, and the active hydrogen content in the low molecular weight initiator in the raw material was 13.33 μmol / g glycolide. According to formula (b) in the specification, the degree of polymerization p of polyglycolic acid in the graft copolymer was greater than 67.

[0243] Example 7 The synthesis method was the same as that of Example 4, except that no antioxidant was added. The hydroxyl content derived from EVOH in the raw material was 0.164 mmol / g glycolide, and the active hydrogen content in the low molecular weight initiator in the raw material was 13.33 μmol / g glycolide. According to formula (b) in the specification, the degree of polymerization p of polyglycolic acid in the graft copolymer was greater than 309.

[0244] Example 8 The synthesis method was the same as that of Example 2, except that serinol was used instead of 1,4-butanediol, the ratios of the polymer initiator and the low molecular weight initiator were changed to 0.02 phr and 0.04 phr, respectively, and the water content of glycolide was 220 ppm. The hydroxyl content derived from EVOH in the raw material was 3.28 μmol / g glycolide, and the active hydrogen content in the low molecular weight initiator in the raw material was 25.41 μmol / g glycolide. According to formula (b) in the specification, the degree of polymerization p of polyglycolic acid in the graft copolymer was greater than 155.

[0245] Example 9 The synthesis method was the same as that of Example 2, except that the ratio of glycolide (water content 200 ppm), stannous octoate, EVOH, 1,4-butanediol, antioxidant 1010, and antioxidant 626 was set to 100:0.1:0.015:0.035:0.3:0.6. The hydroxyl content derived from EVOH in the raw material was 2.46 μmol / g glycolide, and the active hydrogen content in the low molecular weight initiator in the raw material was 18.89 μmol / g glycolide. According to formula (b) in the specification, the degree of polymerization p of polyglycolic acid in the graft copolymer was greater than 103.

[0246] Example 10 The synthesis method was the same as that of Example 4, except that the catalyst was changed to stannous octoate, the ratio of glycolide (water content 180 ppm), stannous octoate, EVOH, 1,4-butanediol, antioxidant 1010, and antioxidant 626 was set to 100:0.1:0.005:0.045:0.3:0.6, the feed rate and screw rotation speed were changed to 3 kg / h and 150 rpm, respectively, and the temperatures were changed to 160°C, 200°C, 220°C, 220°C, 220°C, 220°C, 220°C, 230°C, 235°C, and 240°C. The hydroxyl content derived from EVOH in the raw material was 0.895 μmol / g glycolide, and the active hydrogen content in the low molecular weight initiator in the raw material was 20.00 μmol / g glycolide. According to formula (b) in the specification, the degree of polymerization p of the polyglycolic acid in the graft copolymer was greater than 166.

[0247] Example 11 The synthesis method was the same as that of Example 4, except that the water content of the raw material glycolide was 150 ppm, the catalyst was changed to stannous octoate, and the polymer initiator was changed to PVA. The hydroxyl content derived from PVA in the raw material was 0.179 mmol / g glycolide, and the active hydrogen content in the low molecular weight initiator in the raw material was 8.33 μmol / g glycolide. According to formula (b) in the specification, the degree of polymerization p of polyglycolic acid in the graft copolymer was greater than 53.

[0248] <Comparative Example 1> The synthesis method was the same as that of Example 10, except that no polymeric initiator was used and the ratio of glycolide (water content 180 ppm), stannous octoate, 1,4-butanediol, antioxidant 1010, and antioxidant 626 was changed to 100:0.1:0.05:0.3:0.6. The active hydrogen content of the low molecular weight initiator in the raw material was 21.11 μmol / g glycolide.

[0249] <Comparative Example 2> The commercially available pure polyglycolide (PGA) was a GMP grade glycolide homopolymer purchased from Corbion PURAC, The Netherlands, with an average intrinsic viscosity of 1.2 dl / g.

[0250] <Comparative Example 3> The synthesis method was the same as that in Example 11, except that the amount of PVA was increased to 10 phr. The hydroxyl content derived from PVA in the raw material was 1.79 mmol / g glycolide, and the active hydrogen content in the low molecular weight initiator in the raw material was 8.33 μmol / g glycolide. According to formula (b) in the specification, the degree of polymerization p of polyglycolic acid in the graft copolymer was greater than 10.

[0251] <Comparative Example 4> The multimodal molecular weight distribution polyglycolic acid composition obtained in Example 11 and the commercially available PGA homopolymer in Comparative Example 2 were physically blended at a mass ratio of 1:1. The blending equipment was a PolyLab® internal mixer, the rotor was a roller-type rotor, the rotation speed was set to 50 rpm, the temperature was set to 240°C, and the time was set to 5 minutes.

[0252] The proportions of the raw materials in the above examples and comparative examples are shown in Table 1.

[0253] [Table 1]

[0254] Note: All percentages in the table above are based on 100 parts by weight (phr) of glycolide monomer. The small molecule initiator total includes both the small molecule initiator added and the water contained in the glycolide.

[0255] <Test Example 1> The molecular weights of some examples and comparative examples were characterized by GPC. The analytical results are shown in Table 2. The GPC curves of some examples and comparative examples are shown in Figure 1.

[0256] [Table 2]

[0257] *Calculated from the integrated area ratio of the GPC curve. The ordinate and abscissa of the GPC curve relate to the amount of substance and the molecular weight of the polymer, respectively, so the mass of the corresponding component can be determined by integrating the curve, i.e., the ratio of the integrated area to the total integrated area is the corresponding mass ratio.

[0258] Table 2 lists the analytical results of each peak calculated separately after peak separation, along with the overall molecular weight and its distribution when all peaks are analyzed as a whole. The percentage of high molecular weight peaks refers to the ratio of the area of ​​peaks with a weight average molecular weight greater than 500,000 g / mol to the total peak area. As can be seen from Table 2, multiple peaks appeared in all examples, and the weight average molecular weights of the peaks with higher molecular weights were all greater than 1,000,000 g / mol, and the overall molecular weights were all greater than 180,000 g / mol. The overall molecular weight distribution was also much broader than that of the comparative examples, particularly as reflected by the overall molecular weight polydispersity index being greater than 2. In particular, the overall molecular weight polydispersity index of Example 4 was 11.36.

[0259] Additionally, as can be seen from Table 2, the high molecular weight fraction with a weight-average molecular weight of more than 500,000 g / mol accounted for approximately 1 to 53% of the total, with the highest percentage being approximately 52%. The addition of a small amount of PVA or EVOH in the present invention can form a large amount of high molecular weight polyglycolic acid graft copolymer, and a polyglycolic acid composition with a multimodal molecular weight distribution was obtained in situ from the polymerization reaction. Although the resulting product had a multimodal distribution and was not a perfect ultra-high molecular weight polyglycolic acid graft copolymer, the overall molecular weight of the resulting product was generally still much higher than the overall molecular weight of polyglycolic acid in the prior art.

[0260] As can be seen from Comparative Example 3, when the amount of polymeric initiator used was too much, the hydroxyl content in the raw material was too high, thus providing too many active sites, which in turn led to a decrease in the molecular weight of the final product, and the effect of improving melt strength could not be achieved.

[0261] <Test Example 2> Melt flow rate tests were carried out on some of the examples and comparative examples, and the test results are shown in Table 3.

[0262] [Table 3]

[0263] As can be seen from Table 3, the melt flow rate of each example was significantly lower than that of Comparative Example 2, and the melt flow rate of some examples was too small to be detected, i.e., lower than 0.1 g / 10 min, which is the lower detection limit of the MFR instrument. It can be seen that the polymer of the present invention had a low melt flow rate, which was more advantageous for its application in the fields of casting and film blowing.

[0264] In addition, it can be seen from Comparative Example 3 that when too much PVA was used as a polymer initiator, the melt flow rate began to increase instead. The MFR of Comparative Example 3 was so large that it exceeded the upper limit of detection of the instrument under these conditions (~500 g / 10 min).

[0265] <Test Example 3> Mechanical properties were tested for several examples and comparative examples. According to GB / T1040.2-2006, the samples were injection molded into 5A tensile test specimens (thickness: 2 mm) using a HAAKE MiniJet micro-injection molding machine. Tensile tests were then performed using an Instron Model 3344 material testing machine (USA) at a tensile speed of 50 mm / min and a clamp spacing of 50 mm. Typical stress-strain curves from the tensile tests (results for an individual typical specimen) are shown in Figure 2. Specific results (average values ​​for five tested specimens) are shown in Table 4.

[0266] [Table 4]

[0267] As can be seen from Table 4, the polyglycolic acid composition with a multimodal molecular weight distribution obtained by the present invention had significantly improved toughness compared to conventional polyglycolic acids. The injection-molded test piece of Comparative Example 2 (PGA homopolymer) had a breaking elongation and breaking energy of 6.9% and 13.8*10, respectively. 4 J / m 2 Figure 2 shows that the injection-molded specimen of Example 9 of the present invention exhibited a typical brittle fracture, with only a high elongation at break and a ductile fracture with a long yield plateau (approximately 22% to 80%) on the tensile stress-strain curve. The tensile properties of polyglycolic acid with this special high toughness and yield characteristics were a completely unexpected and unexpected discovery about polyglycolic acid.

[0268] The strength and modulus of Example 9 were comparable to those of Comparative Example 2, but the breaking elongation and breaking energy of the polymer of the present invention were increased by an order of magnitude, with the breaking elongation and breaking energy increasing by 74% and 126.3*10, respectively. 4 J / 2 The breaking elongation of Examples 1 and 3 was lower than that of Example 9, but the tensile modulus was slightly higher than that of Example 9, and all were significantly better than the tensile modulus of Comparative Examples 1 and 2. The other Examples were not significantly inferior to Example 3.

[0269] In addition, a comparison between Comparative Example 4 (blended sample) and Example 8, which had similar molecular weights and distributions, showed that the mechanical properties of Example 8 were significantly higher than those of Comparative Example 4, indicating that the in situ prepared composition (Example 8) had better uniformity than the composition obtained by physical blending (Comparative Example 4). In fact, during the blending process, the viscosity of the multimodal PGA raw material in Comparative Example 4 (Example 11) was too high, making it difficult to quickly mix the composition obtained by physical blending with another polymer by melt stirring. When the multiple phases of the blend were unevenly mixed, one of the most obvious manifestations on a macroscopic scale was the obvious decrease in mechanical properties due to stress concentration.

[0270] <Test Example 4> Some examples and comparative examples were subjected to melt stretching tests at 235° C. to characterize their melt strength. The test results are shown in Table 5 and FIG.

[0271] [Table 5]

[0272] As can be seen from Table 5, the melt strength of the polyglycolic acid compositions obtained in the present invention (Examples 1 and 9) was significantly increased compared to the polyglycolic acid homopolymer (Comparative Examples 1 and 2). The melt strength increased from 0.3 cN (Comparative Example 2) to 20 cN (Example 1), an increase of more than 60 times, fully demonstrating that the polyglycolic acid compositions of the present invention possessed a unique and unexpectedly high melt strength. The other examples were not significantly inferior to Example 9.

[0273] <Test Example 5> Comparative Example 4 (blended sample) and Example 8 (in situ synthesized sample), which had similar molecular weights and distributions, were prepared into thin sheets and quenched at low temperatures until fracture. The microscopic morphology of their cross sections was characterized by scanning electron microscopy. The results are shown in Figure 8 (Comparative Example 4) and Figure 9 (Example 8). As shown in Figure 8, due to the excessively high viscosity of the multimodal PGA raw material (Example 11) in Comparative Example 4, when mixed, it was difficult to remove low-boiling compounds, such as air and moisture, contained in the raw materials during the blending process. This resulted in the formation of defects, which caused stress concentration, which was one of the important causes of the deterioration of mechanical properties. As can be seen from Figure 9, the surface of Example 8 obtained by in situ synthesis was relatively rough, but without obvious defects. The rough surface was due to the fact that Example 8 still showed ductile fracture at the same low temperature due to its better toughness, which was an indication of better mechanical properties.

[0274] Examples of films are provided below.

[0275] Example A1 As shown in Figure 4, a multilayer film was produced using Labtech's LCR-33 HD multilayer coextrusion blown film machine. Low-density polyethylene (Dow LDPE 310E) for the protective layer, maleic anhydride-grafted linear low-density polyethylene (Dow BYNEL® 41E687B) for the tie layer, and the polyglycolic acid composition of Example 9 for the barrier layer were added to the hoppers 10a, 10b, and 10c of three single-screw extruders, respectively, melted, extruded through a melt pump to increase pressure, distributed through a coextrusion distributor, then extruded through a film blowing die, and finally drawn, cooled, stretched, and wound up to obtain a polyglycolic acid multilayer composite film with high barrier performance. The screw rotation speeds of the three single-screw extruders 20a, 20b, and 20c were 58 rpm, 42 rpm, and 25 rpm, respectively. The temperatures of the extruder, melt pump, and die were set to 180°C, 230°C, 230°C, and 230°C, respectively. The rotational speeds of the three melt pumps 30a, 30b, and 30c were 30 rpm, 15 rpm, and 10 rpm, respectively. The outlet pressures of the melt pumps were 120 bar, 110 bar, and 47 bar, respectively. The total thickness of the film was approximately 80 μm.

[0276] Example A2 The method of preparation was the same as that of Example A1, except that the material of the barrier layer was changed to the polyglycolic acid composition of Example 1, the screw rotation speeds of three single-screw extruders 20a, 20b, and 20c were set to 50 rpm, 42 rpm, and 35 rpm, respectively, the rotation speeds of three melt pumps 30a, 30b, and 30c were set to 30 rpm, 15 rpm, and 25 rpm, respectively, and the outlet pressures of the melt pumps were 120 bar, 110 bar, and 58 bar, respectively. The total thickness of the film was about 88 μm.

[0277] Example A3 The screw rotation speeds of the three single-screw extruders 20a, 20b, and 20c were set to 40 rpm, 40 rpm, and 30 rpm, respectively, the rotation speeds of the three melt pumps 30a, 30b, and 30c were set to 15 rpm, 15 rpm, and 5 rpm, respectively, and the outlet pressures of the melt pumps were 102 bar, 97 bar, and 58 bar, respectively, and the production method was the same as that of Example A2. The total thickness of the film was about 50 μm.

[0278] Example A4 The screw rotation speeds of the three single-screw extruders 20a, 20b, and 20c were set to 40 rpm, 40 rpm, and 20 rpm, respectively, the rotation speeds of the three melt pumps 30a, 30b, and 30c were set to 15 rpm, 15 rpm, and 3 rpm, respectively, and the outlet pressures of the melt pumps were 102 bar, 99 bar, and 51 bar, respectively, and the production method was the same as that of Example A2. The total thickness of the film was about 50 μm.

[0279] Example A5 The screw rotation speeds of the three single-screw extruders 20a, 20b, and 20c were set to 40 rpm, 20 rpm, and 20 rpm, respectively, the rotation speeds of the three melt pumps 30a, 30b, and 30c were set to 15 rpm, 15 rpm, and 1 rpm, respectively, and the outlet pressures of the melt pumps were 95 bar, 62 bar, and 39 bar, respectively, and the production method was the same as that of Example A2. The total thickness of the film was about 80 μm.

[0280] <Comparative Example A1> The production method was the same as that of Example A1, except that the material of the barrier layer was changed to polyglycolic acid in Comparative Example 1. However, the melt properties (melt strength and melt toughness) of Comparative Example 1 were so poor that the film bubble was prone to cracking, making continuous film blowing impossible.

[0281] <Comparative example A2> The preparation method was the same as that of Example A1, except that there was no barrier layer, i.e., low density polyethylene (Dow LDPE 310E) was used to replace the polyglycolic acid composition of Example 9 and was placed in hopper 10c, and other process conditions remained unchanged.

[0282] <Comparative example A3> The preparation method was the same as that of Example A1, except that there was no tie layer, i.e., low density polyethylene (Dow LDPE 310E) was used to replace maleic anhydride grafted linear low density polyethylene (Dow BYNEL® 41E687B) and was charged into hopper 10b, and other process conditions remained unchanged.

[0283] <Comparative example A4> The polyglycolic acid pellets obtained in Example 9 were processed using a single-screw extruder (E30P type) (screw diameter: 30 mm, length-to-diameter ratio: 30:1) manufactured by Dr. Collin, Germany, and a calorie film blowing machine (BL180 / 600 type) manufactured by the same company, to obtain a monolayer polyglycolic acid film after melting, extrusion, drawing, cooling, stretching, and winding processes. The screw rotation speed of the extruder was 50 rpm, and the extruder and die temperatures were set to 180°C, 230°C, 230°C, and 230°C, respectively. The film thickness was 24 μm.

[0284] <Test Example A1> The multilayer film obtained in Example A2 was cut with a blade and placed under an optical microscope to observe its cross-sectional structure, and the resulting photograph is shown in Figure 7. As shown in Figure 7, the multilayer film was a five-layer composite film as designed in Figure 6, in which the lighter-colored central layer was a polyglycolic acid composition barrier layer having a thickness of about 15 μm, the outermost layer, which was lighter in color and had a white reflection, was a polyethylene protective layer having a monolayer thickness of about 20 μm, and the darker layer between the barrier layer and the protective layer was a tie layer having a monolayer thickness of about 15 μm.

[0285] <Test Example A2> The films of some examples and comparative example A3 were subjected to delamination force tests with a specimen width of 15 mm, and the test results are listed in Table A2.

[0286] [Table 6]

[0287] Comparing the peel forces of the Examples in Table A2 with those of Comparative Example A3 (multilayer film without a tie layer) shows that after the addition of the tie layer, the adhesion between the layers was significantly improved, with the peel force increasing by at least an order of magnitude, up to 3.61 N / 15 mm, making the layers more difficult to peel.

[0288] <Test Example A3> The examples and comparative example A4 were subjected to heat seal strength tests with a test piece width of 15 mm. The test results are listed in Table A3.

[0289] [Table 7]

[0290] Note: Because the heat seal strength is greater than the interlayer peel force, the layers actually peeled off during the test, making it impossible to obtain an accurate heat seal strength. Here, the maximum load was used as the lower limit of the heat seal strength.

[0291] As can be seen from Table A3, the use of polyolefin as the outer layer in the present invention not only protected the barrier layer of the polyglycolic acid composition, but also significantly improved the heat seal performance of the multilayer film from being completely unheat sealable to a heat seal strength of at least 5 N / 15 mm.

[0292] <Test Example A4> The barrier performance of the example and comparative example A2 was tested. The test temperature for oxygen barrier performance was 23°C, and the relative humidity (RH) was 65%. The test temperature for water vapor barrier performance was 38°C, the relative humidity was 90%, the pressure was 1 standard atmosphere (atm), and the test time was 24 hours. The test results are shown in Table A4.

[0293] [Table 8]

[0294] As shown in Table A4, the oxygen barrier and water barrier properties of each Example were excellent. The water vapor transmission rate was comparable to that of the polyethylene multilayer film (Comparative Example A2), but the oxygen transmission rate was significantly lower than that of the polyethylene multilayer film (Comparative Example A2), with the lowest value being 1.52 cm 3 / (m 2 ·day·atm), which was close to the oxygen barrier properties of pure polyglycolic acid. That is, the multilayer composite film of the present invention not only significantly improved the oxygen barrier properties of the multilayer film due to the high barrier properties of the multimodal molecular weight distribution polyglycolic acid composition, but also prevented the multimodal molecular weight distribution polyglycolic acid from coming into contact with water due to the inherent hydrophobicity and water barrier properties of the polyolefin (thereby reducing the degradation rate of the multilayer film and extending the storage period and useful life of the multilayer film).

[0295] It should be noted that the above-described examples are used only to illustrate the present invention and do not constitute any limitation to the present invention. Although the present invention has been described with reference to exemplary embodiments, it should be understood that the words used therein are descriptive and explanatory, rather than limiting, terms. The present invention may be modified as specified within the scope of the claims of the present invention, and may be modified without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials, and examples, this does not mean that the present invention is limited to the specific examples disclosed therein. On the contrary, the present invention may be extended to all other methods and applications having the same functions.

[0296] All publications, patent applications, patents and other references mentioned in this specification are incorporated herein by reference.Unless otherwise defined, all technical and scientific terms used herein have the meanings that are commonly understood by those skilled in the art.In the event of conflict, the definitions in this specification shall prevail.

[0297] When this specification uses the prefix "well-known to those skilled in the art," "prior art," or similar terms to introduce materials, substances, methods, processes, apparatus, or components, etc., the subject matter introduced by the prefix not only encompasses subject matter that is widely used in the art at the time this application is filed, but also includes subject matter that is not currently in widespread use but that becomes recognized in the art as being suitable for a similar purpose.

[0298] The end points of ranges and any values ​​disclosed herein are not limited to precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values.For numerical ranges, the end point values ​​of each range, the end point values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, and should be considered as specifically disclosed herein.In principle, each technical solution can be combined with each other to obtain new technical solutions, and should also be considered as specifically disclosed herein.

[0299] In the context of this specification, except as expressly stated, any matter or item not directly mentioned adopts without any modification what is known in the art.

[0300] Furthermore, any embodiment described in this specification may be freely combined with one or more other embodiments described in this specification, and the technical solutions or technical ideas formed thereby shall be deemed to be part of the original disclosure or original record of the present invention, and shall not be deemed to be new content not disclosed or anticipated in this specification, unless a person skilled in the art would deem the combination to be obviously unreasonable. [Brief explanation of the drawings]

[0301] [Figure 1] 1 shows GPC curves of Examples 1, 4, and 9 and Comparative Example 2. [Figure 2] 1 shows tensile stress-strain curves of tensile tests of injection-molded test pieces of Examples 1, 3, and 9, and Comparative Example 2. [Figure 3] The melt strength test results for Examples 1 and 9 and Comparative Example 2 are shown. [Figure 4] 1 is a schematic diagram of a multilayer coextrusion film blowing apparatus having a uniaxial stretching device. [Figure 5]1 is a schematic diagram of a multilayer coextrusion casting film making apparatus having a uniaxial stretching device. [Figure 6] 1 is a schematic diagram of the structure of a multilayer composite film according to an embodiment of the present invention. [Figure 7] 1 is an optical microscope photograph of Example A2. [Figure 8] 1 is a scanning electron micrograph of a cross section of Comparative Example 4 (blended composition) at 200x magnification. [Figure 9] 1 is a scanning electron micrograph of a cross section of Example 8 (in-situ synthesized composition) at 200x magnification.

Claims

1. A polymer composition comprising a polyester graft copolymer and a polyester homopolymer, The molecular weight of the polyester graft copolymer is higher than the molecular weight of the polyester homopolymer. Furthermore, the polyester graft copolymer is represented by the following formula A, 【Chemistry 1】 In equation A, x and y １ And, y ２ And z each independently represents the degree of polymerization. PM stands for polyester chain, Furthermore, the degree of polymerization of the polyester chain is p, x and p are independently greater than 0 numbers, and y １ And, y ２ And z are each independent numbers that are greater than or equal to 0. Furthermore, the polyester homopolymer and the polyester chain in the polyester graft copolymer are derived from one or more monomers for polyester, Polymer composition.

2. The polyester graft copolymer and the polyester homopolymer are formed simultaneously in situ. The polymer composition according to claim 1.

3. The polyester homopolymer and the polyester chain in the polyester graft copolymer are derived from a hydroxy acid monomer or a derivative of a hydroxy acid monomer. Preferably, the polyester homopolymer and the polyester chain in the polyester graft copolymer are derived from lactide monomers, lactone monomers, or a combination thereof. Preferably, the lactide monomer is a lactide monomer based on an α-hydroxy acid or a β-hydroxy acid. Furthermore, more preferably, the lactide monomer is selected from the group consisting of glycolide, lactide, butyrolactide, valerolactide, caprolactide, and any combination thereof. Preferably, the lactone monomer is selected from the group consisting of β-butyrolactone, δ-valerolactone, ε-caprolactone, β-propiolactone, β-valerolactone, γ-butyrolactone, γ-valerolactone, γ-octaractone, β-methyl-δ-valerolactone, δ-stearolactone, 2-methyl-ε-caprolactone, 4-methyl-ε-caprolactone, ε-octaractone, ε-palmitractone, and any combination thereof. Furthermore, more preferably, the lactone monomer is selected from the group consisting of β-butyrolactone, δ-valerolactone, ε-caprolactone, and any combination thereof. Most preferably, the monomer is selected from the group consisting of methyl glycolate, glycolic acid, glycolide, and any combination thereof. The polymer composition according to claim 1.

4. When the polyester graft copolymer contains a polyvinyl alcohol main chain, the amount of the polyvinyl alcohol main chain in the polyester graft copolymer is 0.001 to 5 parts by mass, preferably 0.005 to 3 parts by mass, preferably 0.005 to 1 part by mass, and more preferably 0.01 to 1 part by mass, relative to 100 parts by mass of the polyester in the polyester graft copolymer and the polyester homopolymer. Furthermore / or, When the polyester graft copolymer contains an ethylene-vinyl alcohol copolymer main chain, the amount of the ethylene-vinyl alcohol copolymer main chain in the polyester graft copolymer is 0.001 to 10 parts by mass, preferably 0.002 to 8 parts by mass, preferably 0.005 to 7 parts by mass, and more preferably 0.01 to 5 parts by mass, relative to 100 parts by mass of the polyester in the polyester graft copolymer and the polyester homopolymer. Furthermore / or, With respect to the total mass of the polyester graft copolymer and the polyester homopolymer, the content of the polyester graft copolymer is 0.1% to 80.0% by mass, preferably 0.5% to 55.0% by mass, more preferably 1.0% to 30.0% by mass, and the content of the polyester homopolymer is 20% to 99.9% by mass, preferably 45.0% to 99.5% by mass, more preferably 70.0% to 99.0% by mass. A polymer composition according to any one of claims 1 to 3.

5. The overall weight-average molecular weight of the polymer composition is 180,000 to 1,500,000 g / mol, preferably 200,000 to 1,500,000 g / mol, and more preferably 250,000 to 500,000 g / mol. and / or, The overall molecular weight polydispersity index of the polymer composition is 1.5 to 20.0, preferably 2.0 to 12.0, preferably 2.0 to 6.0, and more preferably 2.0 to 3.

5. and / or, The number of peaks in the molecular weight distribution of the polymer composition is at least 2, preferably 2 to 4. and / or, The weight-average molecular weight of the polyester graft copolymer is 500,000 to 10,000,000 g / mol, preferably 1,000,000 to 6,000,000 g / mol. and / or, The polydispersity index of the polyester graft copolymer is 1.0 to 3.0, preferably 1.1 to 1.

5. and / or, The weight-average molecular weight of the polyester homopolymer is 50,000 to 350,000 g / mol, preferably 100,000 to 200,000 g / mol. and / or, The polydispersity index of the polyester homopolymer is 1.0 to 3.0, preferably 1.4 to 2.

9. A polymer composition according to any one of claims 1 to 3, characterized in that...

6. A polymer composition according to any one of claims 1 to 3, Its molecular weight distribution is multimodal. The polyester graft copolymer is a polyglycolic acid graft copolymer, and the polyester homopolymer is a polyglycolic acid homopolymer. The aforementioned polyglycolic acid graft copolymer is represented by formula (I), 【Chemistry 2】 In equation (I), x and y １ And, y ２ z and p each independently represent the degree of polymerization. x and p each independently represent numbers greater than 0, and y １ And, y ２ And z represents a number that is greater than or equal to 0, independently of each other. Polymer composition.

7. x and y １ and y ２ The sum of x, y, and z is 50 or more, preferably 50 to 6000, more preferably 200 to 2500, and / or, p is 40 or more, preferably 50 or more, more preferably 70 to 2000. and / or, x + y １ +y ２ The proportion of z to the sum of +z is between 0% and 50%. and / or, x + y １ +y ２ For the sum of y １ The percentage ranges from 0% to 32%. The polymer composition according to claim 1.

8. The sum of x, y1, y2, and z is 50 or more, preferably 50 to 6000, more preferably 200 to 2500. and / or, p is 40 or more, preferably 50 or more, more preferably 70 to 2000. and / or, The proportion of z to the sum of x + y¹ + y² + z is between 0% and 50%. and / or, The proportion of y1 to the sum of x + y1 + y2 is between 0% and 32%. The polymer composition according to claim 6.

9. The aforementioned polyglycolic acid homopolymer is represented by formula (II), 【Transformation 3】 In equation (II), n １ , ..., n ｉ These are the degrees of polymerization, i is directly connected to R 【Chemistry 4】 The number of such that i ≥ 1, M ｉ These are imino group (-NH-) and nitrilo group 【Transformation 5】 Or it is an ether bond (-O-), R is at least one of hydrogen, an aliphatic group, or an aromatic group. Furthermore, if i > 1, M １ M ２ , , M ｉ They are different from each other, or the same as each other, and also, n １ , n ２ , ..., n ｉ They are different from each other, or the same as each other. Furthermore / or, preferably, i is any integer between 1 and 20, and the preferred range of i is 1 to 6. The sum of all n values ​​is between 100 and 5000, preferably between 1000 and 4000. Furthermore, R is hydrogen and / or an alkyl or aromatic hydrocarbon group having a molecular weight of 14 to 1000 g / mol. The polymer composition according to claim 6, characterized in that...

10. The polyglycolic acid segment 【Transformation 6】 Per 100 parts by mass, If the polyglycolic acid graft copolymer contains a polyvinyl alcohol main chain, then 0.001 to 5 parts by mass, preferably 0.005 to 3 parts by mass, preferably 0.005 to 1 part by mass, more preferably 0.01 to 1 part by mass 【Transformation 7】 and / or, If the polyglycolic acid graft copolymer contains an ethylene-vinyl alcohol copolymer main chain, then 0.001 to 10 parts by mass, preferably 0.002 to 8 parts by mass, preferably 0.005 to 7 parts by mass, more preferably 0.01 to 5 parts by mass 【Transformation 8】 Furthermore, 0.001 to 1 part by mass, preferably 0.01 to 0.1 part by mass 【Chemistry 9】 Contains The polymer composition according to claim 6, characterized in that...

11. The overall weight-average molecular weight of the polymer composition is 180,000 to 1,500,000 g / mol, preferably 200,000 to 1,500,000 g / mol, preferably 250,000 to 500,000 g / mol. and / or, The overall molecular weight polydispersity index of the polymer composition is 1.5 to 20.0, preferably 2.0 to 12.0, preferably 2.0 to 6.0, and more preferably 2.0 to 3.

5. and / or, The number of peaks in the molecular weight distribution of the polymer composition is at least 2, preferably 2 to 4. and / or, The weight-average molecular weight of the polyglycolic acid graft copolymer is 500,000 to 10,000,000 g / mol, preferably 1,000,000 to 6,000,000 g / mol. and / or, The polydispersity index of the polyglycolic acid graft copolymer is 1.0 to 3.0, preferably 1.1 to 1.

5. and / or, The weight-average molecular weight of the polyglycolic acid homopolymer is 50,000 to 350,000 g / mol, preferably 100,000 to 200,000 g / mol. and / or, The polydispersity index of the polyglycolic acid homopolymer is 1.0 to 3.0, preferably 1.4 to 2.

9. The polymer composition according to claim 6, characterized in that...

12. With respect to the total mass of the polyglycolic acid graft copolymer and the polyglycolic acid homopolymer, The content of the polyglycolic acid graft copolymer is 0.1% to 80.0% by mass, preferably 0.5% to 55.0% by mass, and more preferably 1.0% to 30.0% by mass. Furthermore, The content of the polyglycolic acid homopolymer is 20% to 99.9% by mass, preferably 45.0% to 99.5% by mass, and more preferably 70.0% to 99.0% by mass. Furthermore / or, The melt flow rate of the polymer composition at 230°C / 2.16 kg is 20.0 g / 10 min or less, preferably 0.5 to 10.0 g / 10 min. Furthermore / or, The melt strength of the polymer composition at 235°C is 5 cN or more, preferably 8 cN or more, and 200 cN or less, preferably 100 cN or less. The polymer composition according to claim 6, characterized in that...

13. The process includes the step of melt-polymerizing a monomer for polyester, a polymer initiator, and a low molecular weight initiator to provide the polymer composition. A method for preparing a polymer composition according to any one of claims 1 to 3.

14. The monomer is selected from hydroxy acid monomers or derivatives of hydroxy acid monomers. Preferably, the monomer is selected from lactide monomers, lactone monomers, or a combination thereof. Preferably, the lactide monomer is a lactide monomer based on an α-hydroxy acid or a β-hydroxy acid. More preferably, the lactide monomer is selected from the group consisting of glycolide, lactide, butyrolactide, valerolactide, caprolactide, and any combination thereof. Preferably, the lactone monomer is selected from the group consisting of β-butyrolactone, δ-valerolactone, ε-caprolactone, β-propiolactone, β-valerolactone, γ-butyrolactone, γ-valerolactone, γ-octaractone, β-methyl-δ-valerolactone, δ-stearolactone, 2-methyl-ε-caprolactone, 4-methyl-ε-caprolactone, ε-octaractone, ε-palmitractone, and any combination thereof. More preferably, the lactone monomer is selected from the group consisting of β-butyrolactone, δ-valerolactone, ε-caprolactone, and any combination thereof. Most preferably, the monomer is selected from the group consisting of methyl glycolate, glycolic acid, glycolide, and any combination thereof. Furthermore / or, The polymer initiator is at least one of polyvinyl alcohol and ethylene-vinyl alcohol copolymer. Furthermore / or, The degree of alcohol decomposition of the aforementioned polyvinyl alcohol is 68% to 99%. and / or, The degree of polymerization of the polyvinyl alcohol is 100 to 6000, preferably 300 to 2000. Furthermore / or, The ethylene segment content in the ethylene-vinyl alcohol copolymer is greater than 0 mol% to 50 mol%, Furthermore / or, The degree of polymerization of the ethylene-vinyl alcohol copolymer is 50 to 6000, preferably 300 to 2000. Furthermore / or, The melt flow rate of the ethylene-vinyl alcohol copolymer at 190°C / 2.16 kg is 0.1 to 50 g / 10 min. Furthermore / or, The low molecular weight initiator is selected from the group consisting of water and / or hydroxyl and / or amino group-containing low molecular weight compounds having a boiling point above 160°C. Preferably, the molecular weight of the hydroxyl and / or amino group-containing low molecular weight compound is 1000 g / mol or less, preferably 60 to 300 g / mol. The preparation method according to claim 13, characterized in that

15. The hydroxyl content, calculated as hydroxyl and contained by the polymer initiator per gram of monomer, is 0.1 μmol / g monomer to 1.5 mmol / g monomer, preferably 0.5 μmol / g monomer to 1.0 mmol / g monomer, more preferably 1.0 μmol / g monomer to 0.5 mmol / g monomer. Furthermore / or, The active hydrogen content, calculated as active hydrogen and contained in each gram of monomer by the low molecular weight initiator, is 3.0 μmol / g monomer to 40.0 μmol / g monomer, preferably 10.0 μmol / g monomer to 30.0 μmol / g monomer. Furthermore / or, The total amount of active hydrogen, calculated as active hydrogen and contained in each gram of monomer by the polymer initiator and the low molecular weight initiator, is 3.1 μmol / g monomer to 1.54 mmol / g monomer, preferably 10.5 μmol / g monomer to 1.03 mmol / g monomer, and more preferably 11.0 μmol / g monomer to 530.0 μmol / g monomer. Furthermore / or, The amount of polymer initiator used per 100 parts by mass of the monomer is: When the polymer initiator is polyvinyl alcohol, the amount is 0.001 to 5 parts by mass, preferably 0.005 to 3 parts by mass, preferably 0.005 to 1 part by mass, more preferably 0.01 to 1 part by mass. and / or, When the polymer initiator is an ethylene-vinyl alcohol copolymer, the amount is 0.001 to 10 parts by mass, preferably 0.002 to 8 parts by mass, preferably 0.005 to 7 parts by mass, and more preferably 0.01 to 5 parts by mass. Furthermore / or, The amount of the low molecular weight initiator used per 100 parts by mass of the monomer is 0.001 to 1 part, preferably 0.01 to 0.1 parts. The preparation method according to claim 13, characterized in that

16. The conditions for the aforementioned melt polymerization are: A temperature of 120 to 300°C, preferably 160 to 250°C, more preferably 200 to 240°C. and / or, A reaction time of 0.5 to 60 minutes, preferably 1 to 10 minutes. and / or, The melt polymerization is carried out in a melt mixing apparatus, preferably in a continuous twin-screw extrusion apparatus. Includes, Preferably, the polymerization reaction conditions for the continuous twin-screw extruder are: A temperature of 180 to 250°C, preferably 210 to 240°C. and / or, Screw rotation speed of 5 to 300 rpm, preferably 40 to 150 rpm. and / or, A length-to-diameter ratio of 25 to 80, preferably 40 to 70. including, The preparation method according to claim 13, characterized in that

17. The melt polymerization is carried out in at least two twin-screw extrusion facilities connected in series. Preferably, the polymerization reaction conditions for each twin-screw extruder connected in series are: A temperature of 180 to 250°C, preferably 210 to 240°C. and / or, Screw rotation speed of 5 to 300 rpm, preferably 40 to 150 rpm. and / or, A length-to-diameter ratio of 25 to 80, preferably 40 to 70. including, The preparation method according to claim 13, characterized in that

18. The aforementioned melt polymerization is carried out in the presence of a catalyst and an optional antioxidant. Preferably, the catalyst is a salt compound of at least one metal element from Group IIA to Group VA and a transition metal element, or an organoguanidine catalyst. More preferably, the catalyst is a salt compound of at least one of Sn, Bi, Mg, Al, Ca, Fe, Mn, Ti, and Zn, and even more preferably, a Sn salt. Furthermore / or, The amount of the catalyst used per 100 parts by mass of the monomer is 0.005 to 1 part by mass, preferably 0.01 to 0.2 parts by mass. Furthermore / or, The amount of the antioxidant used per 100 parts by mass of the monomer is 0 to 2 parts by mass, preferably 0.01 to 1 part by mass. The preparation method according to claim 13.

19. A polymer composition prepared by the preparation method described in claim 13.

20. Selected from the group consisting of films, rods, tubes, wires, sheets, irregularly shaped parts, and any combination thereof, An article comprising the polymer composition according to any one of claims 1 to 3.

21. The article is a film, Preferably, the film is a multilayer composite film. At least one layer of the multilayer composite film comprises the polymer composition described in any one of claims 1 to 3. Preferably, the multilayer composite film comprises a barrier layer, a protective layer, and a tie layer. The aforementioned protective layer is the outer layer, The tie layer is located between the barrier layer and the protective layer. Furthermore, the barrier layer comprises the polymer composition described in any one of claims 1 to 3. Furthermore / or, The oxygen permeability (OTR) of the multilayer composite film at 23±0.5℃ and a relative humidity of 65%±5% is 100 cm². ３ / (m ２ (day atm) or less, preferably 30 cm ３ / (m ２ (day ATM) is less than or equal to, Furthermore / or, The water vapor transmission rate (WVTR) of the multilayer composite film at 38 ± 0.5°C and a relative humidity of 90% ± 5% is 30 g / m². ２ (day atm) or less, preferably 15 g / (m ２ (day ATM) is less than or equal to, Furthermore / or, The heat seal strength of the aforementioned multilayer composite film is 3 N / 15 mm or more, preferably 5 N / 15 mm or more. Furthermore / or, The interlayer peel strength of the aforementioned multilayer composite film is 0.5 N / 15 mm or more, preferably 1.5 N / 15 mm or more. The article according to claim 20.

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