A translucent polyglycolic acid composition and preparation method thereof

Abstract

The present invention discloses a translucent polyglycolic acid composition and a preparation method thereof. The composition comprises polyglycolic acid, a nucleating agent, and an antioxidant. The nucleating agent is used in an amount of 0.1-6 parts by weight per 100 parts by weight of the polyglycolic acid; the antioxidant is used in an amount of 0.1-1.5 parts by weight. The nucleating agent is an inorganic nucleating agent with a particle size of 1 to 300 nm. The material prepared by the present invention has good light transmittance, with a maximum transmittance of 67%.

Description

Technical Field

[0001] The present invention relates to the technical field of polyglycolic acid materials, and in particular to a translucent polyglycolic acid composition and a preparation method thereof. Background Art

[0002] Polyglycolic acid (PGA) is a biodegradable polymer with excellent biodegradability, good mechanical strength, and excellent gas barrier properties. It is very suitable for the preparation of disposable degradable films. However, due to the structural characteristics of PGA, its transmittance is only 40%, which greatly limits its wider application. Therefore, improving the transmittance of PGA is of great significance.

[0003] Because polyglycolic acid (PGA) has a high crystallization temperature and rapid crystallization rate, conventional nucleating agents have limited ability to regulate PGA crystallization behavior. Existing research results lack practical examples of effective transparency enhancement in PGA. CN202010836786.6 discloses a polyglycolic acid composition, its preparation method, and its application. The composition includes polyglycolic acid, a polyisocyanate compound, and an anti-hydrolysis stabilizer. However, while its purpose is to improve hydrolysis stability, the improvement in light transmittance is minimal. Summary of the Invention

[0004] In view of this, the main purpose of the present invention is to provide a translucent polyglycolic acid composition and a preparation method thereof. The material prepared by the present invention has good light transmittance, and its optimal light transmittance can reach 67%.

[0005] To achieve the above-mentioned object, the present invention adopts the following technical solution: a translucent polyglycolic acid composition, comprising polyglycolic acid, a nucleating agent and an antioxidant, wherein the amount of the nucleating agent is 0.1-6 parts by weight relative to 100 parts by weight of the polyglycolic acid; the amount of the antioxidant is 0.1-1.5 parts by weight;

[0006] Wherein, the nucleating agent is an inorganic nucleating agent with a particle size of 1 to 300 nm.

[0007] According to the composition of the present invention, the polyglycolic acid has a weight-average molecular weight of 50,000 to 300,000, a melt index of 5 to 36 g / 10 min at 240°C, and a tensile modulus of 6,000 to 8,000 MPa. Preferably, the polyglycolic acid has a weight-average molecular weight of 100,000 to 150,000, a melt index of 15 to 30 g / 10 min at 240°C, and a melt index of 2.16 kg / m2 at 240°C.

[0008] The composition according to the present invention further comprises 0-5 parts by weight of a chain extender, wherein the chain extender is selected from at least one of an isocyanate chain extender and an epoxy chain extender, preferably an epoxy chain extender. The isocyanate chain extender is preferably at least one of diphenylmethane diisocyanate and hexamethylene diisocyanate. These chain extenders can organically modify the inorganic nucleating agent, improving its dispersion in the material, promoting the formation of a crystalline system with fine and regularly distributed crystals, and enhancing the transparency of the material.

[0009] According to the composition of the present invention, the amount of the nucleating agent is preferably 0.5-5 parts by weight, the amount of the chain extender is preferably 0-3 parts by weight, and the amount of the antioxidant is preferably 0.3-0.8 parts by weight, relative to 100 parts by weight of polyglycolic acid. More preferably, the amount of the nucleating agent is 0.5-2 parts by weight, and the amount of the chain extender is 1-2 parts by weight, relative to 100 parts by weight of polyglycolic acid.

[0010] According to the composition of the present invention, the inorganic nucleating agent is selected from at least one of nano-silica, talc, calcium carbonate, and montmorillonite, and preferably has a particle size of 5-300 nm, such as, but not limited to, nano-silica with a particle size of 7-40 nm, talc with a particle size of 100-300 nm, and calcium carbonate with a particle size of 20-60 nm. By selecting the type and particle size of the inorganic nucleating agent, the material obtained from the composition can be made finely crystalline, reducing reflection and refraction of light and improving the material's light transmittance.

[0011] According to the composition of the present invention, the antioxidant is selected from at least one of hindered phenol antioxidants, phosphite antioxidants and thioester antioxidants, preferably hindered phenol antioxidants and / or phosphite antioxidants; more preferably, the antioxidant is selected from at least one of antioxidant 1330, antioxidant 245, antioxidant 168 and antioxidant 626.

[0012] Another aspect of the present invention provides a method for preparing the polyglycolic acid composition, comprising the following steps:

[0013] The polyglycolic acid composition is obtained by uniformly mixing polyglycolic acid, a nucleating agent, an antioxidant, and an optional chain extender, melt-blending the mixture, and extruding the mixture into granules through a twin-screw extruder. The term "optionally" as used herein means that the mixture may or may not be added.

[0014] According to the preparation method of the present invention, the polyglycolic acid is dried before mixing, and the drying conditions include: drying temperature of 40-80° C.; drying time of 4-10 hours, preferably 80° C. for 4 hours.

[0015] According to the preparation method of the present invention, the melt blending conditions include: a temperature of 225-250° C., preferably 230-240° C.; and an extruder speed of 60-130 r / min, preferably 90-120 r / min.

[0016] Another aspect of the present invention provides a translucent polyglycolic acid material prepared by the above preparation method.

[0017] Furthermore, the translucent polyglycolic acid material can be processed into corresponding products using equipment such as a tablet press, a casting machine, and a film blowing machine that are well known to those skilled in the art.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] The present invention adds an inorganic nucleating agent of the aforementioned type and particle size to a polyglycolic acid system to improve the light transmittance of the resulting material. The present invention also adds a chain extender to a polyglycolic acid resin system to change the molecular structure of the polyglycolic acid, thereby also improving the light transmittance of pure polyglycolic acid to a certain extent. Furthermore, the inorganic nucleating agent and chain extender selected in the present invention have a synergistic effect in the polyglycolic acid. The chain extender can organically modify the inorganic nucleating agent and promote the dispersion of the inorganic nucleating agent, thereby improving the light transmittance of the material.

[0020] It has been confirmed that the material prepared from the polyglycolic acid composition of the present invention has good light transmittance, and the best light transmittance can reach 67%. DETAILED DESCRIPTION

[0021] The present invention is further described below with reference to the embodiments. However, the present invention is not limited to the listed embodiments but also includes equivalent improvements and variations of the technical solutions defined in the claims attached to the present application.

[0022] The endpoints of the ranges 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 endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0023] In the following examples and comparative examples:

[0024] (1) Main raw materials

[0025] Polyglycolic acid, weight average molecular weight of 130,000, melt index of 26 g / 10 min (240 ° C, 2.16 kg), commercially available;

[0026] Inorganic nucleating agent nanosilica, particle size 7-40 nm, purchased from Aladdin Reagent (Shanghai) Co., Ltd.

[0027] Inorganic nucleating agent nano-talc powder, particle size 100-300 nm, purchased from Beijing Chemical Reagent Co., Ltd.

[0028] Inorganic nucleating agent nano calcium carbonate, particle size 20-60 nm, purchased from Beijing Dekedaojin Technology Co., Ltd.;

[0029] The epoxy chain extender was ADR-4468, purchased from Shanghai Kain Chemical Co., Ltd.

[0030] Isocyanate chain extender: diphenylmethane diisocyanate; purchased from Aladdin Reagent (Shanghai) Co., Ltd.

[0031] Antioxidant A was antioxidant 168, purchased from Qingdao Jidejia New Material Technology Co., Ltd.

[0032] Antioxidant B was antioxidant 1330, purchased from Qingdao Jidejia New Material Technology Co., Ltd.

[0033] Other raw materials used in the examples and comparative examples are all commercially available.

[0034] (2) Characterization and testing

[0035] Light transmittance test method:

[0036] An appropriate amount of translucent polyglycolic acid material was weighed and molded into a sheet of 50 mm × 50 mm × 0.3 mm. The light transmittance of the sheet was measured using a light transmittance meter according to the GB T 2410-2008 method.

[0037] Crystallinity test method:

[0038] The crystallinity of the sample was characterized by DSC. Test conditions: nitrogen atmosphere, -50~240℃, 10K / min. The melting enthalpy ΔH of the sample during the second heating cycle was measured. m , and use the following relationship to calculate the crystallinity of the sample.

[0039]

[0040] Where ΔH m represents the PGA melting enthalpy, The melting enthalpy of 100% crystalline PGA is 183.2 J / g.

[0041] The following examples are used to illustrate the polyglycolic acid composition and its preparation method of the present invention.

[0042] Example 1

[0043] 10 kg of polyglycolic acid (PGA dried at 80°C for 4 hours), 0.05 kg of a nucleating agent (nanosilica), 0.02 kg of antioxidant A (antioxidant 168), and 0.02 kg of antioxidant B (antioxidant 1330) were mixed in a high-speed mixer for 3 minutes, then melt-blended and extruded into pellets using a twin-screw extruder. The twin-screw extruder had a screw length-to-diameter ratio of 26 / 1, a screw speed of 120 rpm, and an extrusion and blending temperature of 230°C.

[0044] Example 2

[0045] 10 kg of polyglycolic acid (PGA, dried as in Example 1), 0.1 kg of a nucleating agent (nanosilica), 0.02 kg of antioxidant A (antioxidant 168), and 0.02 kg of antioxidant B (antioxidant 1330) were mixed in a high-speed mixer for 3 minutes. The mixture was then melt-blended and extruded into pellets using a twin-screw extruder. The twin-screw extruder had a screw length-to-diameter ratio of 26 / 1, a screw speed of 120 rpm, and a screw extrusion and blending temperature of 240°C.

[0046] Example 3

[0047] 10 kg of polyglycolic acid (PGA, dried as in Example 1), 0.2 kg of nano-silica, 0.02 kg of antioxidant A (antioxidant 168), and 0.02 kg of antioxidant B (antioxidant 1330) were mixed in a high-speed mixer for 3 minutes, then melt-blended and extruded into pellets using a twin-screw extruder to obtain a polyglycolic acid material. The twin-screw extruder had a screw length-to-diameter ratio of 26:1, a screw speed of 110 rpm, and an extrusion and blending temperature of 235°C.

[0048] Example 4

[0049] 10 kg of polyglycolic acid (PGA, dried as in Example 1), 0.05 kg of nanosilica, 0.1 kg of a chain extender (ADR-4468), 0.02 kg of antioxidant A (antioxidant 168), and 0.02 kg of antioxidant B (antioxidant 1330) were mixed in a high-speed mixer for 3 minutes, then melt-blended and extruded into pellets using a twin-screw extruder to obtain a polyglycolic acid material. The twin-screw extruder had a screw length-to-diameter ratio of 26:1, a screw speed of 100 rpm, and a screw extrusion and blending temperature of 240°C.

[0050] Example 5

[0051] 10 kg of polyglycolic acid (PGA, dried as in Example 1), 0.1 kg of ADR-4468, 0.02 kg of antioxidant A (antioxidant 168), and 0.02 kg of antioxidant B (antioxidant 1330) were mixed in a high-speed mixer for 3 minutes. The mixture was then melt-blended and extruded into pellets using a twin-screw extruder to obtain a polyglycolic acid material. The twin-screw extruder had a screw length-to-diameter ratio of 26 / 1, a screw speed of 100 rpm, and an extrusion and blending temperature of 235°C.

[0052] Example 6

[0053] 10 kg of polyglycolic acid (PGA, dried as in Example 1), 0.1 kg of nano-talc, 0.2 kg of diphenylmethane diisocyanate, 0.02 kg of antioxidant A (antioxidant 168), and 0.02 kg of antioxidant B (antioxidant 1330) were mixed in a high-speed mixer for 3 minutes, then melt-blended and extruded into granules using a twin-screw extruder. The twin-screw extruder had a screw length-to-diameter ratio of 26 / 1, a screw speed of 90 rpm, and an extrusion and blending temperature of 240°C.

[0054] Example 7

[0055] 10 kg of polyglycolic acid (PGA, dried as in Example 1), 0.2 kg of nano-calcium carbonate, 0.2 kg of hexamethylene diisocyanate, 0.02 kg of antioxidant A (antioxidant 168), and 0.02 kg of antioxidant B (antioxidant 1330) were mixed in a high-speed mixer for 3 minutes, then melt-blended and extruded into pellets using a twin-screw extruder. The twin-screw extruder had a screw length-to-diameter ratio of 26 / 1, a screw speed of 90 rpm, and a screw extrusion and blending temperature of 240°C.

[0056] The light transmittance of the sheets made from the polyglycolic acid materials in Examples 1-7 was tested, and the relevant data is shown in Table 1.

[0057] Table 1

[0058] Crystallinity / % Transmittance / % Example 1 45 62 Example 2 45 65 Example 3 44 59 Example 4 42 67 Example 5 41 57 Example 6 41 63 Example 7 42 60

[0059] Comparative Example 1

[0060] 10 kg of PGA, 0.02 kg of antioxidant A, and 0.02 kg of antioxidant B were stirred in a high-speed mixer for 3 minutes and then melt-blended and extruded into pellets using a twin-screw extruder. The twin-screw extruder had a screw length-to-diameter ratio of 26:1, a screw speed of 120 rpm, and a screw extrusion and blending temperature of 230°C.

[0061] Comparative Example 2

[0062] 10 kg of polyglycolic acid (PGA), 0.1 kg of a commercially available nucleating agent (TMC 300), 0.02 kg of antioxidant A (Antioxidant 168), and 0.02 kg of antioxidant B (Antioxidant 1330) were mixed in a high-speed mixer for 3 minutes, then melt-blended and extruded into pellets using a twin-screw extruder. The twin-screw extruder had a screw length-to-diameter ratio of 26:1, a screw speed of 100 rpm, and an extrusion and blending temperature of 240°C.

[0063] Comparative Example 3

[0064] 10 kg of polyglycolic acid (PGA), 1 kg of nanosilica, 0.02 kg of antioxidant A (antioxidant 168), and 0.02 kg of antioxidant B (antioxidant 1330) were stirred in a high-speed mixer for 3 minutes and then melt-blended and extruded into pellets using a twin-screw extruder to obtain a polyglycolic acid material. The twin-screw extruder had a screw length-to-diameter ratio of 26:1, a screw speed of 90 rpm, and an extrusion and blending temperature of 240°C.

[0065] Comparative Example 4

[0066] 10 kg of polyglycolic acid (PGA, dried as in Example 1), 0.2 kg of calcium carbonate (particle size 1-3 μm), 0.2 kg of hexamethylene diisocyanate, 0.02 kg of antioxidant A (Antioxidant 168), and 0.02 kg of antioxidant B (Antioxidant 1330) were mixed in a high-speed mixer for 3 minutes, then melt-blended and extruded into granules using a twin-screw extruder to obtain a polyglycolic acid material. The twin-screw extruder had a screw length-to-diameter ratio of 26 / 1, a screw speed of 90 rpm, and an extrusion and blending temperature of 240°C.

[0067] The light transmittance of the sheets made from the polyglycolic acid materials in Comparative Examples 1-4 was tested, and the relevant data are shown in Table 2.

[0068] Table 2

[0069] Crystallinity / % Transmittance / % Comparative Example 1 41 40 Comparative Example 2 47 43 Comparative Example 3 49 45 Comparative Example 4 43 38

[0070] As can be seen from the results of the Examples, Comparative Examples, and Tables 1-2, the light transmittance of the materials prepared from the systems comprising polyglycolic acid, an inorganic nucleating agent, and an antioxidant in Examples 1-3 of the present invention is significantly improved, at least 20% higher than the 40% light transmittance of pure PGA. Furthermore, referring to Example 4, the best light transmittance enhancement effect is achieved when an inorganic nucleating agent and a chain extender are simultaneously added to the polyglycolic acid system, their dosage ratio is controlled, and the inorganic nucleating agent is combined with the preferred particle size. Furthermore, the light transmittance of the material prepared from the system comprising polyglycolic acid, a chain extender, and an antioxidant in Example 5 is also somewhat improved compared to pure PGA.

[0071] At the same time, compared with Example 1, Comparative Example 1 does not add an inorganic nucleating agent, Comparative Example 2 selects other types of nucleating agents, and Comparative Example 3 adds too much inorganic nucleating agent, which has little effect on improving the transmittance; Compared with Example 7, Comparative Example 4 has an inappropriate particle size of the added inorganic nucleating agent, and has no effect on improving the transmittance.

[0072] Obviously, the above embodiments of the present invention are merely examples for the purpose of illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not possible to enumerate all embodiments here. Any obvious variations or modifications arising from the technical solutions of the present invention are intended to fall within the spirit and scope of the present invention.

Claims

1. A translucent polyglycolic acid composition, characterized in that: The invention comprises polyglycolic acid, a nucleating agent and an antioxidant, wherein the amount of the nucleating agent is 0.1-2 parts by weight relative to 100 parts by weight of the polyglycolic acid; the amount of the antioxidant is 0.1-1.5 parts by weight; Wherein, the nucleating agent is an inorganic nucleating agent with a particle size of 1 to 300 nm; The inorganic nucleating agent is selected from at least one of nano-silicon dioxide, talc, calcium carbonate and montmorillonite.

2. The polyglycolic acid composition according to claim 1, wherein: The polyglycolic acid has a weight average molecular weight of 50,000 to 300,000, a melt index of 2.16 kg at 240° C. of 5 to 36 g / 10 min, and a tensile modulus of 6,000 to 8,000 MPa.

3. The polyglycolic acid composition according to claim 2, wherein: The weight average molecular weight of the polyglycolic acid is 100,000 to 150,000, 2.16 kg, and the melt index at 240° C. is 15 to 30 g / 10 min.

4. The polyglycolic acid composition according to claim 1 or 2, characterized in that: The invention also includes 0-5 parts by weight of a chain extender, wherein the chain extender is selected from at least one of an isocyanate chain extender and an epoxy chain extender.

5. The polyglycolic acid composition according to claim 4, wherein: The chain extender is an epoxy chain extender.

6. The polyglycolic acid composition according to claim 4, wherein: Relative to 100 parts by weight of polyglycolic acid, the amount of the nucleating agent is 0.5-2 parts by weight; the amount of the chain extender is 0-3 parts by weight; and the amount of the antioxidant is 0.3-0.8 parts by weight.

7. The polyglycolic acid composition according to claim 6, wherein: The amount of the chain extender is 1-2 parts by weight relative to 100 parts by weight of polyglycolic acid.

8. The polyglycolic acid composition according to claim 1, wherein: The antioxidant is selected from at least one of hindered phenol antioxidants, phosphite antioxidants and thioester antioxidants.

9. The polyglycolic acid composition according to claim 8, wherein: The antioxidant is a hindered phenol antioxidant and / or a phosphite antioxidant.

10. The polyglycolic acid composition according to claim 9, wherein: The antioxidant is selected from at least one of antioxidant 1330, antioxidant 245, antioxidant 168 and antioxidant 626.

11. The polyglycolic acid composition according to claim 4, wherein: Wherein, relative to 100 parts by weight of polyglycolic acid, the amount of the nucleating agent is 0.5-2 parts by weight, the amount of the chain extender is 1-2 parts by weight, and the amount of the antioxidant is 0.3-0.8 parts by weight; The weight average molecular weight of the polyglycolic acid is 100,000 to 150,000, 2.16 kg, and the melt index at 240° C. is 15 to 30 g / 10 min; the particle size of the nucleating agent is 5 to 300 nm, and the chain extender is an epoxy chain extender.

12. The method for preparing the polyglycolic acid composition according to any one of claims 1 to 11, wherein: The steps include: The polyglycolic acid, a nucleating agent, an antioxidant and an optional chain extender are uniformly mixed, melt-blended and extruded into granules through a twin-screw extruder to obtain the polyglycolic acid composition.

13. The method for preparing the polyglycolic acid composition according to claim 12, wherein: The polyglycolic acid is dried before mixing, and the drying conditions include: drying temperature of 40-80° C.; drying time of 4-10 hours; and / or, The melt blending conditions include: a temperature of 225-250° C.; and an extruder speed of 60-130 r / min.

14. The method for preparing the polyglycolic acid composition according to claim 13, wherein: The melt blending conditions include: a temperature of 230-240° C.; and an extruder speed of 90-120 r / min.

15. A translucent polyglycolic acid material obtained by the method according to any one of claims 12 to 14.

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