Highly transparent degradable film material and preparation method and application thereof

Abstract

The application discloses a kind of high transparent degradable film materials and its preparation method and application. The film material is prepared based on PGA using the method of the application, the film material with higher transparency, lower haze can be obtained, and the film material also has improved tensile toughness. The preparation method comprises the following steps: uniformly mixing raw materials, then melt blending extrusion is carried out in double screw extruder and granulation, the obtained particles are pressed into film, then cooled to obtain film, and when cooling, the cooling rate is controlled to be ≥150 ℃ / min, preferably 150-300 ℃ / min;The raw materials include the following components: 90-98 parts by weight of polyglycolic acid, 0.3-2 parts by weight of antioxidant, 0.5-3 parts by weight of melt compatibilizer, 1-5 parts by weight of modifier;The modifier is selected from terephthalamide.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of high polymer materials, and relates to a high-transparent degradable film material and a preparation method and application thereof. BACKGROUND

[0002] In recent years, disposable plastic products have brought heavy burden to the ecological environment. Since the implementation of the "plastic restriction order", degradable high polymer materials have attracted widespread attention. Among them, polyglycolic acid (PGA) is a kind of aliphatic polyester high polymer material with simple chemical structure, complete decomposition polyester structure and the fastest degradation speed. PGA has good biodegradability, biocompatibility, gas barrier property, and excellent mechanical strength. However, PGA has the disadvantages of high brittleness and poor transparency, which seriously limits its wide application in the packaging field. Therefore, it is very important to improve the light transmittance and toughness of PGA.

[0003] CN108003581B discloses a polylactic acid composite material and its application. The composition of the polylactic acid composite material includes polylactic acid, talcum powder and plasticizer. When the polydispersity index of polylactic acid is in the range of 1.55-2.02, by adding talcum powder with particle size of 1-2.6 μm and plasticizer with relative molecular weight of 180-670, a polylactic acid composite material with light transmittance ≥80% and haze ≤40% can be obtained. The key technology of this patent involves the control of dispersion index, but the dispersion of dispersed particles is difficult to monitor in real time in actual operation. In addition, the light transmittance of the material prepared by this patent is still low, and the haze is still large.

[0004] CN111440425A discloses a manufacturing method of high-transparency polylactic acid. The method forms transparent block-shaped material by high-temperature cooking of plant fibers, and then high-temperature mixing and hot pressing into transparent starch block. The transparent starch block is then blended with polylactic acid to obtain high-transparency polylactic acid material. The process steps of this method are relatively complex, and no corresponding data are mentioned for the transparency of the obtained material.

[0005] At present, there are few reports on the use of PGA to prepare biodegradable film materials with high light transmittance and low haze. SUMMARY

[0006] In view of the poor light transmittance (light transmittance less than 70%, haze greater than 80%) and high brittleness of polyglycolic acid (PGA) material, the method of the present application is used to prepare film material based on PGA, which can obtain film material with high transparency and low haze, and the film material also has improved tensile toughness.

[0007] To achieve the purpose of the present application, the following technical solutions are provided:

[0008] In one aspect, the present application provides a preparation method of a high-transparent degradable film material, comprising the following steps:

[0009] The raw materials are mixed uniformly, then melt-blended extruded and granulated in a twin-screw extruder, then film-pressed, and a film is obtained after cooling, and the cooling rate is controlled to be ≥150℃ / min, preferably 150-300℃ / min during the cooling;

[0010] The raw materials include the following components: 90-98 parts by weight of polyglycolic acid, 0.3-2 parts by weight of antioxidant, 0.5-3 parts by weight of melt compatibilizer, and 1-5 parts by weight of modifier.

[0011] The modifier is terephthalamide.

[0012] The polyglycolic acid, antioxidant, melt compatibilizer and specific modifier are combined in the above-mentioned amounts to prepare a film material, and the cooling rate during the cooling process is controlled to be ≥150℃ / min (preferably 150-300℃ / min), which can significantly improve the transparency of the polyglycolic acid film material, significantly reduce its haze, and also achieve good mechanical properties.

[0013] In some embodiments, the weight average molecular weight of the polyglycolic acid is ≥50000, preferably 50000-250000; and the melt index of the polyglycolic acid under a load of 2.16 kg at 240℃ is 5-120 g / 10 min, preferably 10-50 g / 10 min.

[0014] The polyglycolic acid can be a homopolymer of glycolic acid or a copolymer of glycolic acid.

[0015] In some preferred embodiments, the antioxidant is selected from one or more of phosphite antioxidants and hindered phenolic antioxidants; preferably the antioxidant is a combination of phosphite antioxidants and hindered phenolic antioxidants, preferably in a mass ratio of 0.8-1.2:1; the preferred antioxidant is conducive to obtaining a film material with better thermal oxidation resistance.

[0016] Further preferably, the phosphite antioxidant is selected from one or more of antioxidant 168, antioxidant 626 and antioxidant 9228; and the hindered phenolic antioxidant is selected from one or more of antioxidant 1010 and antioxidant 1330.

[0017] In some preferred embodiments, the melt compatibilizer is selected from one or more of epoxy compounds and polyisocyanate compounds. The preferred compatibilizer is conducive to enhancing the melt strength and improving the compatibility of the components, and obtaining a product with better film-forming properties.

[0018] In some preferred embodiments, the epoxy compound is selected from one or more of glycidyl methacrylate-containing copolymers, preferably selected from styrene-acrylonitrile-glycidyl methacrylate copolymers, ethylene-methyl acrylate-glycidyl methacrylate copolymers.

[0019] In some preferred embodiments, the polyisocyanate compound is selected from one or more of toluene-2,4-diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, lysine diisocyanate, and polyisocyanate, preferably polyisocyanate; preferably the polyisocyanate has a viscosity of 150-250 mPa·s at 25℃, an NCO content of 30.2-32 wt%, a functionality of 2.6-2.7, such as PM200 from Wanhua Chemical Group Co., Ltd.

[0020] In some embodiments, the raw material optionally further comprises a nucleating agent, preferably the nucleating agent is used in an amount of 0-10 parts by weight.

[0021] In some embodiments, the nucleating agent is selected from one or more of talc, silica, mica, and glass fiber.

[0022] Preferably, the temperature of the extrusion is controlled to be 225-240℃.

[0023] Preferably, the temperature of the feeding section of the twin-screw extruder is 180-210℃, the temperature of the plasticizing section is 200-230℃, the temperature of the homogenizing section is 220-235℃, and the temperature of the extrusion die is 225-235℃. The preferred conditions facilitate obtaining a film material with better performance.

[0024] The present application also provides a high-transparency degradable film material prepared by the preparation method described above. In some embodiments, the film material obtained by the preparation method of the present application has a ratio of the heat enthalpy of the melting peak to the heat enthalpy of the cold crystallization peak in the DSC heating curve of 2:1-8:1, a crystallinity of the film of less than 30%, a light transmittance of the film of greater than 87%, a haze of the film of less than 10%, and an elongation at break of the film of greater than 260%.

[0025] The present application also provides the use of the high-transparency degradable film material described above in the field of packaging.

[0026] In the present application, a modifier terephthalamide is introduced into the formula system of polyglycolic acid for preparing film material, and combined with other components according to specific amount, in the process of preparing film material, the cooling rate is controlled to be greater than or equal to 150 ℃ / min (preferably 150-300 ℃ / min), which can significantly improve the light transmittance of polyglycolic acid film, significantly reduce the haze, and also can take into account the better tensile toughness. In some embodiments, the PGA film with light transmittance greater than 87% and haze less than 10% is obtained, and the tensile toughness is greatly improved, which widens the application of PGA material in the packaging field. DETAILED DESCRIPTION

[0027] The experimental methods used in the following examples are conventional methods unless otherwise specified.

[0028] The materials, reagents, etc. used in the following examples can be obtained from commercial channels unless otherwise specified.

[0029] The present application will be further described in conjunction with specific examples. It should be understood that the following examples are only used to illustrate the present application and not to limit the scope of the present application.

[0030] Polyglycolic acid (PGA): Shanghai Pujing Chemical Technology Co., Ltd., weight average molecular weight is 150000, melt index is 30 g / 10 min (240 ℃, 2.16 kg);

[0031] Melt compatibilizer: epoxy compound, specifically a copolymer containing a glycidyl methacrylate group, BASF ADR-4468, GMA (glycidyl methacrylate) content is 10% by weight, weight average molecular weight is about 6680 g / mol.

[0032] Antioxidant: compounded from phosphite antioxidant and hindered phenolic antioxidant, specifically antioxidant 168 (tris (2,4-di-tert-butylphenyl) phosphite) and antioxidant 1010 (tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester) are compounded according to a mass ratio of 1:1, commercially available.

[0033] Modifier: terephthalamide, purity is greater than 98%, commercially available.

[0034] The melt index is measured according to the method of GB / T 3682-2000.

[0035] The crystallinity is calculated according to the formula △Hm / 183.2*100%, wherein △Hm is the heat of absorption of the DSC curve.

[0036] The crystallization enthalpy ratio refers to the ratio of the heat of fusion peak of the DSC heating curve to the heat of cold crystallization peak, wherein the enthalpy value is measured by DSC program software.

[0037] The light transmittance was determined using the method of GB / T 2410-2008.

[0038] The haze was determined using the method of GB / T 2410-2008.

[0039] The elongation at break was determined using the method of GB / T 1040.3-2006.

[0040] Example 1

[0041] 1. The PGA was dried in a vacuum oven for use, the drying temperature of the PGA was 80℃, and the drying time was 5 hours.

[0042] 2. The components were mixed according to the formulation in Table 1 (the melt compatibilizer was diphenyl methane diisocyanate), and then the mixed material was placed into a twin-screw extruder, the feeding section temperature of the twin-screw extruder was controlled between 180-210℃, the plasticizing section temperature was controlled between 200-230℃, the homogenizing section temperature was controlled between 220-235℃, and the extrusion die temperature was controlled between 225-235℃; the film material was obtained by melting, extruding and granulating in the twin-screw extruder, and then pressing the film, and cooling at a cooling rate of 150℃ / min.

[0043] The film obtained after cooling was tested for elongation at break, and the results are shown in Table 1.

[0044] The film material obtained was tested by DSC to obtain the DSC heating curve, and the calculated crystallization enthalpy ratio is shown in Table 1.

[0045] The detection results of the crystallinity, light transmittance and haze of the film material obtained are shown in Table 1.

[0046] Example 2

[0047] Reference was made to Example 1, except that the amount of each component was changed, and the cooling rate was changed, and the specific conditions are shown in Table 1. The rest was performed according to Example 1.

[0048] Example 3

[0049] Reference was made to Example 1, except that the amount of each component was changed, and the cooling rate was changed, and the melt compatibilizer used was ADR-4468; the specific conditions are shown in Table 1. The rest was performed according to Example 1.

[0050] Comparative Example 1

[0051] Reference was made to Example 1, except that the cooling rate was changed, and the specific conditions are shown in Table 1. The rest was performed according to Example 1.

[0052] Comparative Example 2

[0053] Refer to the implementation example 1, different in that, the amount of each component is changed, see table 1 for specific conditions. The rest are all in accordance with example 1.

[0054] Comparative example 3

[0055] Refer to the implementation example 1, different in that, the amount of each component is changed, see table 1 for specific conditions. The rest are all in accordance with example 1.

[0056] Table 1 PGA film material ratio (parts by weight) and performance test results

[0057]

[0058]

[0059] According to the above experimental results, it can be seen that the method of the present application can be based on polyglycolic acid to prepare a film product with better performance, which can balance high light transmittance, low haze and excellent elongation at break.

[0060] The application has been described with reference to the embodiments and examples. However, the application is not limited to the aspects described in the above embodiments and examples, and various modifications can be made. It should be understood that various modifications and equivalent replacements can be made by those skilled in the art without departing from the spirit and scope of the application. Therefore, the application is not limited to the specific examples described herein. More precisely, the scope of protection of the application is defined by the appended claims.

Claims

1. A process for the preparation of a highly transparent degradable film material, characterized in that, The method comprises the following steps: The raw materials are mixed uniformly, then melt-blended, extruded and pelletized in a twin-screw extruder, then the film is pressed, cooled and obtained, and the cooling rate is controlled to be ≥150℃ / min during the cooling; The raw materials comprise the following components: 90-98 parts by weight of polyglycolic acid, 0.3-2 parts by weight of antioxidant, 0.5-3 parts by weight of melt compatibilizer, 1-5 parts by weight of modifier; The modifier is terephthalamide; The melt compatibilizer is selected from one or more of the following: epoxy compound selected from copolymer containing glycidyl methacrylate group, and polyisocyanate compound selected from one or more of the following: toluene-2,4-diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, lysine diisocyanate and polyisocyanate.

2. The production method according to claim 1, characterized by, The cooling rate is controlled to be 150-300℃ / min.

3. The production method according to claim 1, characterized by, The weight average molecular weight of the polyglycolic acid is ≥50000; the melt index of the polyglycolic acid under a load of 2.16 kg at 240℃ is 5-120 g / 10min; The polyglycolic acid is a homopolymer of glycolic acid or a copolymer of glycolic acid.

4. The production method according to claim 3, characterized by, The weight average molecular weight of the polyglycolic acid is 50000-250000; The melt index of the polyglycolic acid under a load of 2.16 kg at 240℃ is 10-50 g / 10min.

5. The method of claim 1, wherein, The antioxidant is selected from one or more of the following: phosphite antioxidant and hindered phenolic antioxidant.

6. The production method according to claim 5, wherein The antioxidant is a combination of phosphite antioxidant and hindered phenolic antioxidant.

7. The preparation method according to claim 6, characterized in that, The mass ratio of the phosphite antioxidant and the hindered phenolic antioxidant is 0.8-1.2:

1.

8. The preparation method according to claim 5, characterized in that, The phosphite antioxidant is selected from one or more of the following: antioxidant 168, antioxidant 626 and antioxidant 9228; the hindered phenolic antioxidant is selected from one or more of the following: antioxidant 1010, antioxidant 1330.

9. The method of any one of claims 1-8, wherein, The epoxy compound is selected from one or more of the following: styrene-acrylonitrile-glycidyl methacrylate copolymer, ethylene-methyl acrylate-glycidyl methacrylate copolymer; And / or, the polyisocyanate compound is polyisocyanate.

10. The production method according to claim 9, characterized by, The viscosity of the polyisocyanate at 25℃ is 150-250 mPa·s, the NCO content is 30.2-32% by weight, and the functionality is 2.6-2.

7.

11. The method of any one of claims 1-8, wherein, The raw materials optionally further comprise nucleating agent.

12. The method of claim 11, wherein, The amount of the nucleating agent is 0-10 parts by weight.

13. The preparation method according to claim 11, characterized in that, The nucleating agent is selected from one or more of the following: talc, silica, mica and glass fiber.

14. The method of any one of claims 1-8, wherein, The extrusion temperature is controlled to be 225-240℃.

15. The method of claim 14, wherein, The temperature of the feeding section of the twin-screw extruder is 180-210℃, the temperature of the plasticizing section is 200-230℃, the temperature of the homogenizing section is 220-235℃, and the temperature of the extrusion die is 225-235℃.

16. A high-transparent degradable film material prepared by the method of any one of claims 1-15.

17. The highly transparent degradable film material of claim 16, wherein, The ratio of the heat enthalpy of the melting peak to the heat enthalpy of the cold crystallization peak in the DSC heating curve of the film material is 2:1-8:1, and the crystallinity of the film is less than 30%.

18. The highly transparent degradable film material of claim 16, wherein, The light transmittance of the film is greater than 87%, the haze is less than 10%, and the elongation at break is greater than 260%.

19. Use of the high-transparency degradable film material according to any one of claims 16-18 in the field of packaging.

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