In-situ high molecular weight polyglycolic acid resin and raw material composition, preparation method and application thereof

Abstract

The present invention discloses a raw material composition for preparing an in-situ high-molecular-weight polyglycolic acid resin, comprising the following components: 1000 parts by weight of a glycolide monomer; 0.05-5 parts by weight of an unsaturated initiator; 0.01-1 parts by weight of a catalyst; 0.01-1 parts by weight of a free radical initiator; and 0-50 parts by weight of an auxiliary agent. The raw materials, including the glycolide monomer, the unsaturated initiator, the catalyst, the free radical initiator, and optionally the auxiliary agent, are melt-blended in a screw extruder to obtain the in-situ high-molecular-weight polyglycolic acid resin. The present invention utilizes the unsaturated initiator to initiate ring-opening polymerization of glycolide, which itself can undergo free radical polymerization. These two reactions are simultaneously and continuously performed in the extruder, thereby obtaining an in-situ high-molecular-weight, high-melt-viscosity polyglycolic acid resin.

Description

Technical Field

[0001] The present invention relates to the technical field of polyglycolic acid resins, and more particularly to an in-situ high molecular weight polyglycolic acid resin and a raw material composition, a preparation method and an application thereof. Background Art

[0002] Polyglycolic acid (PGA) is a fully biodegradable polyester that degrades completely within 1 to 3 months under natural conditions. PGA also exhibits excellent biocompatibility, bioresorbability, and mechanical properties. It also offers strong barrier properties to O2 and CO2, is non-toxic, harmless, and environmentally friendly, and has been certified as safe biodegradable in the United States, the European Union, and Japan.

[0003] In the early days, PGA materials were mainly used in the field of medical sutures, and later expanded to the crude oil extraction industry, including fracturing balls or temporary plugging balls (bridge plugs) used in the process of shale oil extraction in the United States, as well as knotted products made with the improvement of technical requirements. In addition, the use of fully biodegradable materials in the packaging field is a general trend and has huge market space. Due to its good mechanical properties and fully biodegradable characteristics, PGA has been tried in this field. It is believed that as its output increases and production costs decrease, PGA will have a wide range of applications in the packaging field. At present, the PGA industry is in its infancy, focusing on production, and there are fewer modified products. However, with the continuous development of the PGA industry, the PGA modification industry has strong growth potential.

[0004] At the same time, PGA materials also have problems such as poor toughness, high processing temperature, narrow processing window and rapid degradation. Targeted modification is needed to achieve the smooth and widespread application of PGA materials in general fields. In addition, the PGA obtained by traditional preparation methods has a relatively low molecular weight and low melt viscosity. Moreover, due to the high processing temperature of PGA, it is inevitable that a certain amount of decomposition will occur during the processing. Therefore, it is difficult to meet the application requirements of extrusion, film making, etc. that require a higher melt viscosity. A common method is to increase the melt viscosity of the PGA raw material by post-polymerization viscosity-increasing modification, thereby broadening its scope of application.

[0005] CN112469764A (Shanghai Pujing Chemical Technology Co., Ltd., March 9, 2021) discloses a polyglycolic acid resin with a branched structure and a preparation method thereof, which is prepared by ring-opening polymerization of glycolide in the presence of a structure regulator and an end-capping agent, and exhibits low melt viscosity and good thermal stability. However, it requires a prepolymerization step, has many overall steps, and a long process. In addition, the low melt viscosity is not suitable for extrusion, film making, and other aspects.

[0006] CN111647144 A (Shanghai Pujing Chemical Technology Co., Ltd., 2020.09.11) discloses a method for adjusting the molecular chain structure of polyglycolic acid, by adding some target functional groups (hydrophilic and hydrophobic groups -OH, -COOR, etc.) or chain segments (branching, copolymerization, etc.) to change the molecular structure, thereby adjusting the performance of polyglycolic acid. The invention mentions that a polyhydroxyl polymer such as polyethylene glycol or starch can be used as an end-capping agent. The polymer is a hydroxylated polymer with a characteristic functional group structure such as polyhydroxyl or carboxyl or hydroxycarboxyl mixed (two or more), and a number average molecular weight of 2000 to 10,000 g / mol. It is proposed that too large a molecular weight will have a steric effect, and too long a time will have low efficiency. Therefore, SAG (epoxy polymer) or polyethylene glycol is added to the end cap 5 minutes (min) before the end of the reaction, but the final product has a low molecular weight (maximum weight average molecular weight of about 200,000 g / mol) and a low intrinsic viscosity, with a maximum of about 1.45dL / g. In addition, the polymerization condition is a low-temperature nitrogen protection reaction, the reaction conditions are harsh, and the reaction time is long, at least 50 minutes. The long reaction time will cause thermal decomposition or degradation of PGA to form by-products with color or odor.

[0007] CN113603869A (Huazhong University of Science and Technology, 2021.11.05) discloses a polyester brush-shaped polymer and its one-pot synthesis method and application. The patent combines two types of reactions: controlled radical polymerization and cyclic monomer catalytic ring-opening polymerization. The one-pot method directly realizes the preparation of brush-shaped polymers from small molecules. However, although the patent is called a one-pot method, in fact, the two reactions of controlled radical polymerization and cyclic monomer catalytic ring-opening polymerization are not carried out at the same time, but are caused to occur one after another by controlling the temperature. And the reaction conditions are relatively harsh, and it is necessary to ensure that the reactor is free of water and oxygen. In addition, the reaction is carried out in solution, which involves the separation and disposal of solvents. The total reaction time is more than 20 hours, which is not efficient.

[0008] In summary, there is an urgent need to develop a rapid and efficient method for preparing high molecular weight, high melt viscosity PGA in this field. Summary of the Invention

[0009] To address the problems encountered in the prior art, the present invention provides an in-situ high-molecular-weight polyglycolic acid resin, its raw material composition, preparation method, and application. This invention utilizes an unsaturated initiator to initiate the ring-opening polymerization of glycolide, which itself can undergo free radical polymerization. These two reactions are carried out simultaneously and continuously in an extruder, thereby producing an in-situ high-molecular-weight, high-melt-viscosity polyglycolic acid resin.

[0010] One of the objects of the present invention is to provide a raw material composition for preparing an in-situ high molecular weight polyglycolic acid resin, comprising a glycolide monomer, an unsaturated initiator, a catalyst, a free radical initiator, and optionally an auxiliary agent;

[0011] The structure of the unsaturated initiator is shown in formula (I):

[0012]

[0013] Wherein R1, R2, R3, and R4 are each independently selected from a group containing at least one of a hydroxyl group, an amino group, or an imino group, H, or a C1-C10 alkyl group; and at least one of R1, R2, R3, and R4 is selected from a substituent structure containing at least one of a hydroxyl group, an amino group, or an imino group.

[0014] Other substances commonly used in the art may also be added to the raw material composition of the present invention, and those skilled in the art may add the corresponding substances according to the use requirements.

[0015] In the raw material composition for preparing in-situ high molecular weight polyglycolic acid resin of the present invention, preferably,

[0016]

[0017] In the raw material composition for preparing in-situ high molecular weight polyglycolic acid resin of the present invention, preferably,

[0018] In the raw material composition, based on 1000 parts by weight of glycolide monomer,

[0019]

[0020] More preferably,

[0021] In the raw material composition, based on 1000 parts by weight of glycolide monomer,

[0022]

[0023] The molecular weight of the unsaturated initiator is 50-1000 g / mol.

[0024] In the raw material composition for preparing in-situ high molecular weight polyglycolic acid resin of the present invention, preferably,

[0025] The unsaturated initiator is selected from at least one of the general structural formulas shown in formula (II), (III), and (IV);

[0026]

[0027] wherein R5 and R6 are each independently selected from a substituent structure comprising at least one of a hydroxyl group, an amino group, or an imino group; and at least one of R7 and R8 is selected from a substituent structure comprising at least one of a hydroxyl group, an amino group, or an imino group;

[0028] Preferably, R5, R6, R7, and R8 are each independently selected from a substituent structure containing at least a hydroxyl group;

[0029] Further preferably, -O-R5, -O-R6, -O-R7, -O-R8 are each independently selected from -(O-CH2-CH2)n-OH, where n≥1.

[0030] In the raw material composition for preparing in-situ high molecular weight polyglycolic acid resin of the present invention, preferably,

[0031] The unsaturated initiator is selected from (Hydroxyethyl methacrylate), (polyethylene glycol methacrylate), (Hydroxyethyl acrylate), (polyethylene glycol acrylate), (monoethylene glycol maleate);

[0032] Preferably, n1 and n2 are each independently selected from any integer greater than or equal to 2;

[0033] More preferably, n1 and n2 are each independently selected from any integer of 2-10.

[0034] In the raw material composition for preparing in-situ high molecular weight polyglycolic acid resin of the present invention, preferably,

[0035] The catalyst is selected from at least one of a metal salt catalyst and an organic guanidine catalyst;

[0036] Preferably, the metal element in the metal salt catalyst is selected from at least one of Group IIA-VA metal elements and transition metal elements;

[0037] More preferably, the metal element of the metal salt catalyst is at least one selected from Sn, Bi, Mg, Al, Ca, Fe, Mn, Ti and Zn; more preferably, Sn;

[0038] More preferably,

[0039] The metal salt catalyst is selected from at least one of stannous octoate, stannous chloride, and stannous chloride dihydrate; and / or,

[0040] The organic guanidine catalyst is selected from at least one of metformin and metformin hydrochloride.

[0041] More preferably,

[0042] The metal salt catalyst is selected from at least one of stannous octoate, stannous chloride, and stannous chloride dihydrate; and / or,

[0043] The organic guanidine catalyst is selected from at least one of metformin and metformin hydrochloride.

[0044] In the raw material composition for preparing in-situ high molecular weight polyglycolic acid resin of the present invention, preferably,

[0045] The free radical initiator is an organic compound that can decompose to generate free radicals under certain conditions, and the free radical initiator is selected from at least one of acyl peroxides, alkyl peroxides, peroxyacids / esters, ketone peroxides, and azo compounds;

[0046] Preferably, the free radical initiator is selected from at least one of benzoyl peroxide, azobisisobutyl cyanide, dicumyl peroxide, di-tert-butyl peroxide, tert-butyl hydroperoxide, benzoic acid peroxide, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane.

[0047] In the raw material composition for preparing in-situ high molecular weight polyglycolic acid resin of the present invention, preferably,

[0048] The auxiliary agent is selected from at least one of an antioxidant, an anti-hydrolysis agent, a lubricant, and an opening agent; preferably,

[0049] The antioxidant is selected from at least one of hindered phenol antioxidants, phosphite antioxidants, and sulfur-containing antioxidants; and / or,

[0050] The anti-hydrolysis agent is a compound or polymer that reacts with carboxylic acid or water, preventing the occurrence of autocatalytic hydrolysis, thereby extending the lifespan of many polymers, especially polyester polymers. The effect is particularly pronounced in harsh environments such as high temperature, high humidity, and acidic and alkaline environments. The anti-hydrolysis agent is selected from at least one of bis(2,6-diisopropylbenzene)carbodiimide, polycarbodiimide, low molecular weight epoxy prepolymer, anti-hydrolysis stabilizer SAG-005, anti-hydrolysis agent PCD, and anti-hydrolysis agent TMP-2000; and / or,

[0051] The lubricant is a compound or composition that can reduce the intermolecular forces of polymers, thereby improving the processing performance of polymers. The lubricant is selected from at least one of stearic acid, stearate salts, stearic acid esters, polyethylene wax, oleamide, and erucamide; and / or,

[0052] The opening agent is an auxiliary agent that can increase surface roughness and / or reduce surface energy, and the opening agent is selected from at least one of an inorganic opening agent and an organic opening agent;

[0053] More preferably, the inorganic opening agent is selected from at least one of calcium carbonate, talc, calcium oxide, titanium dioxide, aluminum oxide, magnesium oxide, boron nitride, silicon oxide, carbon black, mica, and chalk powder; and / or,

[0054] The organic opening agent is selected from at least one of oleamide and erucamide;

[0055] The hindered phenol antioxidant is selected from: at least one of BHT, 2246, 1010, 1076, and 3114; the phosphite antioxidant is at least one of 168, 626, and 618; the sulfur-containing antioxidant is at least one of DLTDP, DSTDP, DMTDP, DTDTP, 300, and 1035; and the antioxidant is further preferably selected from: at least one of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, N,N'-bis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tris[2,4-di-tert-butylphenyl]phosphite, bis(2,4-dicumylphenyl)pentaerythritol diphosphite, and bis(2,4-di-tert-butylphenyl)propionate]pentaerythritol diphosphite.

[0056] A second object of the present invention is to provide an in-situ high molecular weight polyglycolic acid resin, comprising the following steps:

[0057] The preparation method is prepared by melt blending reaction of components including the raw material composition described in one of the purposes of the present invention.

[0058] In the preparation of the in-situ high molecular weight polyglycolic acid resin according to the present invention, preferably,

[0059] The in situ high molecular weight polyglycolic acid resin has a weight average molecular weight of not less than 250,000 g / mol; preferably 250,000-350,000 g / mol, such as 250,000, 260,000, 270,000, 280,000, 290,000, 300,000, 310,000, 320,000, 330,000, 340,000, 350,000 g / mol, or any range consisting of any two of the above values; and / or

[0060] The melt index under 230°C / 2.16kg conditions is not higher than 15g / 10min; preferably 5-15g / 10min, such as 50,000, 60,000, 70,000, 80,000, 90,000, 100,000, 110,000, 120,000, 130,000, 140,000, 150,000 g / mol and any range consisting of any two of the above values.

[0061] A third object of the present invention is to provide a method for preparing an in-situ high molecular weight polyglycolic acid resin as described in the second object of the present invention, comprising the following steps:

[0062] The in-situ high molecular weight polyglycolic acid resin is obtained by melt blending raw materials including the glycolide monomer, an unsaturated initiator, a catalyst, a free radical initiator and optionally an auxiliary agent in a screw extruder;

[0063] Preferably, the raw material in the preparation method adopts the raw material composition described in one of the objectives of the present invention.

[0064] Preferably, the method for preparing the in situ high molecular weight polyglycolic acid resin comprises the following steps: thoroughly mixing the required amounts of glycolide monomer, unsaturated initiator, catalyst, free radical initiator, and optional auxiliary agents, adding the mixture to an extruder set at a predetermined temperature, performing continuous melting, mixing, and reaction, and cooling and granulating the mixture to obtain the high molecular weight polyglycolic acid resin in situ.

[0065] The unsaturated initiator of the present invention has a hydroxyl, amino, or imino group site that allows the polymerization of cyclic glycolide monomers, primarily initiating the ring-opening polymerization of glycolide. Furthermore, the unsaturated carbon-carbon bonds primarily serve to increase molecular weight by allowing double bonds to open under the action of the free radical initiator and then form bonds with each other. Therefore, the unsaturated initiator in the present invention does not act as an end-capping agent, but rather as an initiator and polymerization site.

[0066] In summary, the polymerization process described in the present invention involves two pathways: (1) ring-opening polymerization of glycolide monomers initiated by an unsaturated initiator; and (2) bonding of the unsaturated initiators to each other under the action of a free radical initiator. These two pathways occur simultaneously, enabling the in situ synthesis of high-molecular-weight polyglycolic acid.

[0067] In the method for preparing the in-situ high molecular weight polyglycolic acid resin of the present invention, preferably,

[0068] The reaction temperature is 180-250°C; preferably 200-240°C; and / or,

[0069] The screw speed of the extruder is 5-300 rpm, preferably 30-200 rpm.

[0070] In the method for preparing the in-situ high molecular weight polyglycolic acid resin of the present invention, preferably,

[0071] The screw extruder is selected from at least one of a single-screw extruder and a twin-screw extruder, and preferably at least two extruders are used in series;

[0072] More preferably,

[0073] At least one single-screw extruder and one twin-screw extruder are connected in series, or at least two twin-screw extruders are connected in series.

[0074] A fourth object of the present invention is to provide the use of the in-situ high molecular weight polyglycolic acid resin described in the second object of the present invention or the in-situ high molecular weight polyglycolic acid resin prepared by the preparation method described in the third object of the present invention in tableware, lunch boxes, film bags, foam materials, and barrier materials.

[0075] The high-molecular-weight, high-melt-viscosity polyglycolic acid resin obtained in situ by the present invention meets the application requirements of extrusion, film making, etc. that require a high melt viscosity, and can effectively expand the scope of application.

[0076] The endpoints and any values ​​of the ranges disclosed in the present invention 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 endpoint values ​​of each range, the endpoint values ​​of each range and a separate point value, and the separate point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered as specifically disclosed in this article. Hereinafter, in principle, each technical solution can be combined with each other to obtain a new technical solution, which should also be considered as specifically disclosed in this article.

[0077] Compared with the prior art, the present invention has at least the following advantages:

[0078] The present invention utilizes an unsaturated initiator to initiate the ring-opening polymerization of glycolide, which itself can undergo free radical polymerization. The two reactions are continuously carried out simultaneously in an extruder, thereby obtaining polyglycolic acid resin with high molecular weight and high melt viscosity in situ. DETAILED DESCRIPTION

[0079] The present invention will be described in detail below with reference to specific embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and are not to be construed as limiting the scope of protection of the present invention. Non-essential improvements and adjustments made by those skilled in the art to the present invention based on the contents of the present invention still fall within the scope of protection of the present invention.

[0080] It should also be noted that the various specific technical features described in the following specific embodiments can be combined in any appropriate manner without contradiction. To avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0081] In addition, the various embodiments of the present invention may be arbitrarily combined as long as they do not violate the concept of the present invention. The technical solutions thus formed belong to part of the original disclosure of this specification and also fall within the scope of protection of the present invention.

[0082] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, for example, they can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0083] Among them, glycolide was purchased from Shenzhen Boli Biomaterial Co., Ltd. with a purity of ≥99.5%.

[0084] Hydroxyethyl methacrylate, trimeryl methacrylate, hydroxyethyl acrylate, trimeryl acrylate, monoethylene glycol maleate, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, stannous octoate, and 1,4-butanediol were all reagent grade and purchased from Sinopharm Chemical Reagent Co., Ltd.

[0085] Antioxidant 1010 was purchased from BASF (China) Co., Ltd., and antioxidant 626 (THP-24) was purchased from Shanghai MacLean Biochemical Technology Co., Ltd., with a purity of ≥95%.

[0086] The present invention performs performance measurement according to the following method:

[0087] Melt flow rate (MFR) was measured in accordance with ISO 1133 using an Instron CEAST MF20 melt indexer. The barrel temperature was 230°C, the load was 2.16 kg, the die diameter was 2.095 mm, and the length was 8 mm. The preheating time was 240 seconds. Samples were automatically cut at set intervals, and the average of five samples was calculated. Results are expressed in grams per 10 minutes (g / 10 min).

[0088] Gel Permeation Chromatography (GPC): Testing was performed on a PL-GPC50 gel permeation chromatograph (Angilent, USA), using GPC offline software. The mobile phase consisted of hexafluoroisopropanol containing 5 mmol / L sodium trifluoroacetate, at a flow rate of 1 mL / min, a column temperature of 40°C, and an injection volume of 100 μL. The standard sample was PMMA, with a sample concentration of 1 mg / mL.

[0089] [Example 1]

[0090] Glycolide (GA), stannous octoate, antioxidant 1010, antioxidant 626, hydroxyethyl methacrylate, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane were uniformly mixed in a mass ratio of 1000:0.1:3:5:0.5:0.1 and then extruded into pellets using a Labtech parallel, co-rotating twin-screw extruder (screw diameter: 20 mm, aspect ratio: 40). The extruder had 11 sections from the feed port to the die, numbered 1-11. Section 1 served only for feeding and was not heated. The temperatures in sections 2-11 were 160°C, 200°C, 200°C, 200°C, 200°C, 200°C, 200°C, 200°C, and 200°C, respectively. The feed rate was 2 kg / h, the screw speed was 100 rpm, and the residence time of the raw materials in the extruder was 2-4 minutes. The melt index was measured as 8.8 g / 10 min and the weight average molecular weight was 321,500 g / mol according to the method described above.

[0091] [Example 2]

[0092] Glycolide (GA), stannous octoate, antioxidant 1010, antioxidant 626, hydroxyethyl methacrylate, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane were uniformly mixed in a mass ratio of 1000:0.2:3:5:1:0.2 and then extruded into pellets using a Labtech parallel, co-rotating twin-screw extruder (screw diameter: 20 mm, aspect ratio: 40). The extruder had 11 sections from the feed port to the die, numbered 1-11. Section 1 served only for feeding and was not heated. The temperatures in sections 2-11 were 160°C, 200°C, 200°C, 200°C, 200°C, 200°C, 200°C, 200°C, and 200°C, respectively. The feed rate was 2 kg / h, the screw speed was 100 rpm, and the residence time of the material in the extruder was 2-4 minutes. The melt index was measured as 8.9 g / 10 min and the weight average molecular weight was 315,600 g / mol according to the method described above.

[0093] [Example 3]

[0094] Glycolide (GA), stannous octoate, antioxidant 1010, antioxidant 626, hydroxyethyl methacrylate, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane were uniformly mixed in a mass ratio of 1000:0.5:3:5:2.5:0.5 and then extruded into pellets using a Labtech parallel, co-rotating twin-screw extruder (screw diameter: 20 mm, aspect ratio: 40). The extruder had 11 sections from the feed port to the die, numbered 1-11. Section 1 served only for feeding and was not heated. The temperatures in sections 2-11 were 160°C, 200°C, 200°C, 200°C, 200°C, 200°C, 200°C, 200°C, and 200°C, respectively. The feed rate was 2 kg / h, the screw speed was 100 rpm, and the residence time of the raw materials in the extruder was 2-4 minutes. The melt index was measured as 14.9 g / 10 min and the weight average molecular weight was 252,100 g / mol according to the method described above.

[0095] [Example 4]

[0096] Glycolide (GA), stannous octoate, antioxidant 1010, antioxidant 626, hydroxyethyl methacrylate, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane were uniformly mixed in a mass ratio of 1000:0.2:3:5:1:0.2 and then extruded into pellets using a Labtech parallel, co-rotating twin-screw extruder (screw diameter: 20 mm, aspect ratio: 40). The extruder had 11 sections from the feed port to the die, numbered 1-11. Section 1 served only for feeding and was not heated. The temperatures in sections 2-11 were 160°C, 200°C, 200°C, 200°C, 200°C, 200°C, 200°C, 200°C, and 200°C, respectively. The feed rate was 2 kg / h, the screw speed was 150 rpm, and the average reaction time for the raw materials was 1.5-3.5 minutes. The melt index was measured as 13.8 g / 10 min and the weight average molecular weight was 265,100 g / mol according to the method described above.

[0097] [Example 5]

[0098] Glycolide (GA), stannous octoate, antioxidant 1010, antioxidant 626, hydroxyethyl methacrylate, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane were uniformly mixed in a mass ratio of 1000:0.2:3:5:1:0.2 and then extruded into pellets using a Labtech parallel, co-rotating twin-screw extruder (screw diameter: 20 mm, aspect ratio: 40). The extruder consisted of 11 sections from the feed port to the die, numbered 1-11. Section 1 served only for feeding and was not heated. The temperatures in sections 2-11 were 160°C, 200°C, 230°C, 230°C, 230°C, 230°C, 230°C, 230°C, 230°C, and 230°C, respectively. The feed rate was 2 kg / h, the screw speed was 150 rpm, and the average reaction time for the raw materials was 1.5-3.5 minutes. The melt index was measured as 11.3 g / 10 min and the weight average molecular weight was 281,000 g / mol according to the method described above.

[0099] [Example 6]

[0100] Glycolide (GA), stannous octoate, antioxidant 1010, antioxidant 626, hydroxyethyl methacrylate, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane were mixed uniformly in a mass ratio of 1000:0.2:3:5:1:0.2 and then extruded into pellets using a Labtech parallel, co-rotating twin-screw extruder (screw diameter: 20 mm, aspect ratio: 40). The extruder had 11 sections from the feed port to the die, numbered 1-11. Section 1 served only for feeding and was not heated. The temperatures in sections 2-11 were 160°C, 200°C, 230°C, 230°C, 230°C, 230°C, 230°C, 230°C, 230°C, and 230°C, respectively. The feed rate was 2 kg / h, the screw speed was 100 rpm, and the residence time of the raw materials in the extruder was 2-4 minutes. The melt index was measured as 7.8 g / 10 min and the weight average molecular weight was 322,400 g / mol according to the method described above.

[0101] [Example 7]

[0102] Glycolide (GA), stannous octoate, antioxidant 1010, antioxidant 626, trimethylene glycol methacrylate, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane were mixed uniformly in a mass ratio of 1000:0.2:3:5:1:0.2 and then extruded into pellets using a Labtech parallel, co-rotating twin-screw extruder (screw diameter: 20 mm, aspect ratio: 40). The extruder had 11 sections from the feed port to the die, numbered 1-11. Section 1 served only for feeding and was not heated. The temperatures in sections 2-11 were 160°C, 200°C, 200°C, 200°C, 200°C, 200°C, 200°C, 200°C, and 200°C, respectively. The feed rate was 2 kg / h, the screw speed was 100 rpm, and the residence time of the material in the extruder was 2-4 minutes. The melt index was measured as 6.3 g / 10 min and the weight average molecular weight was 336,700 g / mol according to the method described above.

[0103] [Example 8]

[0104] Glycolide (GA), stannous octoate, antioxidant 1010, antioxidant 626, trimethylene glycol methacrylate, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane were mixed uniformly in a mass ratio of 1000:0.2:3:5:1:0.2 and then extruded into pellets using a Labtech parallel, co-rotating twin-screw extruder (screw diameter: 20 mm, aspect ratio: 40). The extruder had 11 sections from the feed port to the die, numbered 1-11. Section 1 served only for feeding and was not heated. The temperatures in sections 2-11 were 160°C, 200°C, 200°C, 200°C, 200°C, 200°C, 200°C, 200°C, and 200°C, respectively. The feed rate was 2 kg / h, the screw speed was 100 rpm, and the residence time of the material in the extruder was 2-4 minutes. The melt index was measured as 5.5 g / 10 min and the weight average molecular weight was 343,100 g / mol according to the method described above.

[0105] [Example 9]

[0106] Glycolide (GA), stannous octoate, antioxidant 1010, antioxidant 626, hydroxyethyl acrylate, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane were uniformly mixed in a mass ratio of 1000:0.2:3:5:1:0.2 and then extruded into pellets using a Labtech parallel, co-rotating twin-screw extruder (screw diameter: 20 mm, aspect ratio: 40). The extruder had 11 sections from the feed port to the die, numbered 1-11. Section 1 served only for feeding and was not heated. The temperatures in sections 2-11 were 160°C, 200°C, 200°C, 200°C, 200°C, 200°C, 200°C, 200°C, and 200°C, respectively. The feed rate was 2 kg / h, the screw speed was 100 rpm, and the residence time of the material in the extruder was 2-4 minutes. The melt index was measured as 10.1 g / 10 min and the weight average molecular weight was 292,000 g / mol according to the method described above.

[0107] [Example 10]

[0108] Glycol glycolide (GA), stannous octoate, antioxidant 1010, antioxidant 626, trimerized acrylate, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane were uniformly mixed in a mass ratio of 1000:0.2:3:5:1:0.2 and then extruded into pellets using a Labtech parallel, co-rotating twin-screw extruder (screw diameter: 20 mm, aspect ratio: 40). The extruder had 11 sections from the feed port to the die, numbered 1-11. Section 1 served only for feeding and was not heated. The temperatures in sections 2-11 were 160°C, 200°C, 230°C, 230°C, 230°C, 230°C, 230°C, 230°C, 230°C, and 230°C, respectively. The feed rate was 2 kg / h, the screw speed was 100 rpm, and the residence time of the material in the extruder was 2-4 minutes. The melt index was measured as 8.2 g / 10 min and the weight average molecular weight was 321,000 g / mol according to the method described above.

[0109] [Example 11]

[0110] Glycolide (GA), stannous octoate, antioxidant 1010, antioxidant 626, monoethylene glycol maleate, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane were uniformly mixed in a mass ratio of 1000:0.2:3:5:1:0.2 and then extruded into pellets using a Labtech parallel, co-rotating twin-screw extruder (screw diameter: 20 mm, aspect ratio: 40). The extruder had 11 sections from the feed port to the die, numbered 1-11. Section 1 served only for feeding and was not heated. The temperatures in sections 2-11 were 160°C, 200°C, 200°C, 200°C, 200°C, 200°C, 200°C, 200°C, and 200°C, respectively. The feed rate was 2 kg / h, the screw speed was 100 rpm, and the residence time of the material in the extruder was 2-4 minutes. The melt index was measured as 10.5 g / 10 min and the weight average molecular weight was 273,000 g / mol according to the method described above.

[0111] [Comparative Example 1]

[0112] Glycolide (GA), stannous octoate, antioxidant 1010, antioxidant 626, and 1,4-butanediol (a saturated initiator whose terminal hydroxyl groups can initiate the ring-opening polymerization of glycolide) were mixed uniformly in a mass ratio of 1000:0.2:3:5:1 and then extruded into pellets using a Labtech parallel, co-rotating twin-screw extruder (screw diameter: 20 mm, aspect ratio: 40). The extruder had 11 sections, numbered 1-11, from the feed port to the die. Section 1 served only for feeding and was not heated. The temperatures in sections 2-11 were 160°C, 200°C, 200°C, 200°C, 200°C, 200°C, 200°C, 200°C, and 200°C, respectively. The feed rate was 2 kg / h, the screw speed was 100 rpm, and the residence time of the raw materials in the screw extruder was 2-4 minutes. The melt index was measured as 35.2 g / 10 min and the weight average molecular weight was 106,200 g / mol according to the method described above.

[0113] [Comparative Example 2]

[0114] Glycol (GA), stannous octoate, antioxidant 1010, antioxidant 626, 1,4-butanediol, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane were uniformly mixed in a mass ratio of 1000:0.2:3:5:1:0.2 and then extruded into pellets using a Labtech parallel, co-rotating twin-screw extruder (screw diameter: 20 mm, aspect ratio: 40). The extruder had 11 sections from the feed port to the die, numbered 1-11. Section 1 served only for feeding and was not heated. The temperatures in sections 2-11 were 160°C, 200°C, 200°C, 200°C, 200°C, 200°C, 200°C, 200°C, and 200°C, respectively. The feed rate was 2 kg / h, the screw speed was 100 rpm, and the residence time of the raw materials in the extruder was 2-4 minutes. The melt index was measured as 19.2 g / 10 min and the weight average molecular weight was 203,400 g / mol according to the method described above.

[0115] Comparative Example 2 contains a free radical initiator, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, which acts as a crosslinking agent and increases molecular weight. Therefore, the molecular weight of Comparative Example 2 is slightly higher than that of Comparative Example 1. However, the molecular weight of both Comparative Examples 1 and 2 is significantly lower than that of the polyglycolic acid resin prepared in the examples of the present invention.

[0116] [Comparative Example 3]

[0117] Glycolide (GA), stannous octoate, antioxidant 1010, antioxidant 626, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane were mixed uniformly in a mass ratio of 1000:0.2:3:5:0.2 and then extruded into pellets using a Labtech parallel, co-rotating twin-screw extruder (screw diameter: 20 mm, aspect ratio: 40). The extruder had 11 sections from the feed port to the die, numbered 1-11. Section 1 served only for feeding and was not heated. The temperatures in sections 2-11 were 160°C, 200°C, 200°C, 200°C, 200°C, 200°C, 200°C, 200°C, and 200°C, respectively. The feed rate was 2 kg / h, the screw speed was 100 rpm, and the residence time of the raw materials in the extruder was 2-4 minutes. Under this condition, the degree of polymerization of PGA is very low. After being extruded from the die, it basically flows out in liquid form. According to the method described above, its melt index is measured to be greater than 200g / 10min and its weight-average molecular weight is less than 3000g / mol.

[0118] [Comparative Example 4]

[0119] Glycolide (GA), stannous octoate, antioxidant 1010, antioxidant 626, and hydroxyethyl methacrylate were uniformly mixed in a mass ratio of 1000:0.2:3:5:1 and then extruded into pellets using a Labtech parallel, co-rotating twin-screw extruder (screw diameter: 20 mm, aspect ratio: 40). The extruder had 11 sections from the feed port to the die, numbered 1-11. Section 1 served only for feeding and was not heated. The temperatures in sections 2-11 were 160°C, 200°C, 200°C, 200°C, 200°C, 200°C, 200°C, 200°C, and 200°C, respectively. The feed rate was 2 kg / h, the screw speed was 100 rpm, and the residence time of the raw materials in the screw extruder was 2-4 minutes. The melt index was measured according to the method described above and was 25.1 g / 10 min and the weight average molecular weight was 152,000 g / mol.

[0120] The present invention has been described in detail above with reference to specific embodiments and exemplary examples. However, these descriptions should not be construed as limiting the present invention. Those skilled in the art will appreciate that various equivalent substitutions, modifications, or improvements may be made to the technical solutions and implementations of the present invention without departing from the spirit and scope of the present invention, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A raw material composition for preparing an in-situ high molecular weight polyglycolic acid resin, comprising a glycolide monomer, an unsaturated initiator, a catalyst, a free radical initiator, and optionally an auxiliary agent; wherein the unsaturated initiator is selected from at least one of the general structural formulas shown in formula (II), (III), and (IV); in, -O-R5, -O-R6, -O-R7, -O-R8 are each independently selected from -(O-CH2-CH2)n-OH, n≥1; or, The unsaturated initiator is selected from The molecular weight of the unsaturated initiator is 50-1000 g / mol; In the raw material composition, based on 1000 parts by weight of glycolide monomer, 0.1-3 parts by weight of unsaturated initiator.

2. The raw material composition for preparing in-situ high molecular weight polyglycolic acid resin according to claim 1, characterized in that: In the raw material composition, based on 1000 parts by weight of glycolide monomer, 0.01-1 parts by weight of catalyst; and / or, 0.01-1 parts by weight of a free radical initiator; and / or, 0-50 parts by weight of auxiliary agent.

3. The raw material composition for preparing in-situ high molecular weight polyglycolic acid resin according to claim 1, characterized in that: In the raw material composition, based on 1000 parts by weight of glycolide monomer, The catalyst is 0.02-0.8 parts by weight; and / or, 0.02-0.6 parts by weight of a free radical initiator; and / or, The auxiliary agent is 5-45 parts by weight.

4. The raw material composition for preparing in-situ high molecular weight polyglycolic acid resin according to claim 3, characterized in that: In the raw material composition, based on 1000 parts by weight of glycolide monomer, 0.2-2 parts by weight of unsaturated initiator; and / or, The catalyst is 0.05-0.5 parts by weight; and / or, 0.04-0.4 parts by weight of a free radical initiator; and / or, The auxiliary agent is 10-40 parts by weight.

5. The raw material composition for preparing in-situ high molecular weight polyglycolic acid resin according to claim 1, characterized in that: The unsaturated initiator is selected from At least one of; n1, n2 are each independently selected from any integer greater than or equal to 2.

6. The raw material composition for preparing in-situ high molecular weight polyglycolic acid resin according to claim 5, characterized in that: n1 and n2 are each independently selected from any integer of 2-10.

7. The raw material composition for preparing in-situ high molecular weight polyglycolic acid resin according to claim 1, characterized in that: The catalyst is selected from at least one of a metal salt catalyst and an organic guanidine catalyst.

8. The raw material composition for preparing in-situ high molecular weight polyglycolic acid resin according to claim 7, characterized in that: The metal element in the metal salt catalyst is selected from at least one of Group IIA-VA metal elements and transition metal elements.

9. The raw material composition for preparing in-situ high molecular weight polyglycolic acid resin according to claim 8, characterized in that: The metal element of the metal salt catalyst is selected from at least one of Sn, Bi, Mg, Al, Ca, Fe, Mn, Ti and Zn.

10. The raw material composition for preparing in-situ high molecular weight polyglycolic acid resin according to claim 9, characterized in that: The metal salt catalyst is selected from at least one of stannous octoate, stannous chloride, and stannous chloride dihydrate; and / or, The organic guanidine catalyst is selected from at least one of metformin and metformin hydrochloride.

11. The raw material composition for preparing in-situ high molecular weight polyglycolic acid resin according to claim 1, characterized in that: The free radical initiator is selected from at least one of acyl peroxides, alkyl peroxides, peroxyacids / esters, ketone peroxides, and azo compounds.

12. The raw material composition for preparing in-situ high molecular weight polyglycolic acid resin according to claim 11, characterized in that: The free radical initiator is selected from at least one of benzoyl peroxide, azobisisobutyl cyanide, dicumyl peroxide, di-tert-butyl peroxide, tert-butyl hydroperoxide, benzoic acid peroxide, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane.

13. The raw material composition for preparing in-situ high molecular weight polyglycolic acid resin according to claim 1, characterized in that: The auxiliary agent is selected from at least one of an antioxidant, an anti-hydrolysis agent, a lubricant, and an anti-blocking agent.

14. The raw material composition for preparing in-situ high molecular weight polyglycolic acid resin according to claim 13, characterized in that: The antioxidant is selected from at least one of hindered phenol antioxidants, phosphite antioxidants, and sulfur-containing antioxidants; and / or, The anti-hydrolysis agent is selected from at least one of bis(2,6-diisopropylbenzene)carbodiimide, polycarbodiimide, and low molecular weight epoxy prepolymer; and / or, The lubricant is selected from at least one of stearic acid, stearate, stearate, polyethylene wax, oleamide, and erucamide; and / or, The opening agent is selected from at least one of an inorganic opening agent and an organic opening agent.

15. The raw material composition for preparing in-situ high molecular weight polyglycolic acid resin according to claim 14, characterized in that: The inorganic opening agent is selected from at least one of calcium carbonate, talc, calcium oxide, titanium dioxide, aluminum oxide, magnesium oxide, boron nitride, silicon oxide, carbon black, mica, and chalk powder; and / or, The organic opener is selected from at least one of oleamide and erucamide.

16. An in-situ high molecular weight polyglycolic acid resin comprising: The preparation is prepared by melt blending reaction of components including the raw material composition according to any one of claims 1 to 15.

17. The in-situ high molecular weight polyglycolic acid resin according to claim 16, characterized in that: The weight average molecular weight of the in-situ high molecular weight polyglycolic acid resin is not less than 250,000 g / mol.

18. The in-situ high molecular weight polyglycolic acid resin according to claim 17, characterized in that: The melt index under the conditions of 230℃ / 2.16kg is not higher than 15g / 10min.

19. The in-situ high molecular weight polyglycolic acid resin according to claim 17, wherein: The in-situ high molecular weight polyglycolic acid resin has a weight average molecular weight of 250,000-350,000 g / mol; and / or, The melt index under 230℃ / 2.16kg conditions is 5-15g / 10min.

20. A method for preparing an in-situ high molecular weight polyglycolic acid resin according to any one of claims 16 to 19, comprising the following steps: The in-situ high molecular weight polyglycolic acid resin is obtained by melt blending raw materials including the glycolide monomer, an unsaturated initiator, a catalyst, a free radical initiator and optionally an auxiliary agent in a screw extruder; The raw materials in the preparation method are the raw material composition according to any one of claims 1 to 15.

21. The method for preparing an in-situ high molecular weight polyglycolic acid resin according to claim 20, wherein: The reaction temperature is 180-250°C; and / or, The screw speed of the extruder is 5-300 rpm.

22. The method for preparing an in-situ high molecular weight polyglycolic acid resin according to claim 21, wherein: The reaction temperature is 200-240°C; and / or, The screw speed of the extruder is 30-200 rpm.

23. The method for preparing an in-situ high molecular weight polyglycolic acid resin according to claim 20, wherein: The screw extruder is selected from at least one of a single-screw extruder and a twin-screw extruder.

24. The method for preparing an in-situ high molecular weight polyglycolic acid resin according to claim 23, wherein: At least two extruders are used in series.

25. The method for preparing an in-situ high molecular weight polyglycolic acid resin according to claim 24, wherein: At least one single-screw extruder and one twin-screw extruder are connected in series, or at least two twin-screw extruders are connected in series.

26. Use of the in-situ high molecular weight polyglycolic acid resin according to any one of claims 16 to 19 or the in-situ high molecular weight polyglycolic acid resin prepared by the preparation method according to any one of claims 20 to 25 in tableware, lunch boxes, film bags, foam materials, and barrier materials.

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