Fully biodegradable material and preparation method thereof

Abstract

The invention provides a fully biodegradable material and a preparation method thereof. The full-biodegradable material comprises a full-biodegradable polymer matrix and a compound type anti-hydrolysis agent, wherein the compound type anti-hydrolysis agent is prepared from haplotype carbodiimide and polymeric carbodiimide; the mass percent of the compound type anti-hydrolysis agent in the full biodegradable material is 0.8 to 3 percent; the mass ratio of the haplotype carbodiimide to the polymeric carbodiimide is (5-50): (50-95). The material has a relatively long shelf life, and the biodegradability of a full-biodegradable material can be maintained.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a fully biodegradable material and a preparation method thereof. Background Art

[0002] The shelf life of fully biodegradable plastics currently on the market is generally only about half a year. After the shelf life, the physical properties of the material will drop significantly, which limits the expansion of the application field of fully biodegradable materials. In order to overcome these technical difficulties, researchers generally achieve this through chemical modification and physical modification. Chemical modification is mainly copolymerization modification, that is, by introducing other units with biodegradability but poor biodegradability into the main chain of biodegradable polymers to slow down the overall degradation rate. However, this method can only be implemented smoothly in resin synthesis plants, and it often changes other physical properties of the resin, which may narrow the sales and application scope of the resin. Therefore, it has not aroused the enthusiasm of related companies. Physical modification is mainly based on a simple melt blending process, mainly by adding antioxidants or UV absorbers to delay the aging of the material, but the effect is often not very good, because the main factor affecting the performance degradation of biodegradable materials during storage and use is not oxidative degradation or UV energy degradation, but hydrolysis. Summary of the invention

[0003] In order to solve the above problems in the prior art, the present invention aims to provide a fully biodegradable material and a preparation method thereof. The material has a long shelf life and can maintain the biodegradability of the fully biodegradable material.

[0004] In order to achieve the above-mentioned purpose, according to the first aspect of the present invention, a fully biodegradable material is provided, which includes a fully biodegradable polymer matrix and a composite anti-hydrolysis agent; wherein the composite anti-hydrolysis agent includes a monomeric carbodiimide and a polymeric carbodiimide; the mass percentage of the composite anti-hydrolysis agent in the fully biodegradable material is 0.8-3%; the mass ratio of the monomeric carbodiimide to the polymeric carbodiimide is 5-50:50-95.

[0005] Monomeric carbodiimide can improve the early performance retention rate of mechanical properties of materials in a high temperature and high humidity environment, while polymeric carbodiimide can improve the later performance retention rate in this environment. The combination of the two plays a synergistic role and is more conducive to the maintenance of mechanical properties. In addition, the present invention finds that controlling the ratio of monomeric carbodiimide to polymeric carbodiimide within the above range is more conducive to maintaining the mechanical properties of the fully biodegradable material in a high temperature and high humidity environment.

[0006] In some preferred embodiments of the present invention, the material of the fully biodegradable polymer matrix includes polylactic acid (PLA), polybutylene adipate / terephthalate (PBAT), polybutylene succinate-adipate (PBSA), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), polycaprolactone (PCL), poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P(3HB, 4HB)), polydioxanone (PPDO), polybutylene succinate (PBS), polyglycolic acid (PGA), polypropylene carbonate (PPC), carbon dioxide / ethylene oxide copolymer (PEC), poly-3-hydroxybutyrate (PHB), poly(butylene succinate-terephthalate) (PBST), starch (St), and cellulose (CA), or a combination of two or more thereof.

[0007] In some preferred embodiments of the present invention, the monomeric carbodiimide includes 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide.

[0008] In some preferred embodiments of the present invention, the polymeric carbodiimide comprises polydivinylbenzene bonded with 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide.

[0009] In some preferred embodiments of the present invention, the mass percentage of the composite anti-hydrolysis agent in the fully biodegradable material is 0.8-2%, and more preferably 0.8-1.5%.

[0010] In some preferred embodiments of the present invention, the mass ratio of the monomeric carbodiimide to the polymeric carbodiimide is 10-30:70-90, and more preferably 20:80. When the ratio of the monomeric carbodiimide to the polymeric carbodiimide is within the above preferred range, it is more conducive to the mechanical property maintenance effect of the fully biodegradable material of the present invention.

[0011] According to another aspect of the present invention, there is also provided a method for preparing the above-mentioned fully biodegradable material, which comprises:

[0012] The fully biopolymer and the composite anti-hydrolysis agent are mixed in a high-speed mixer, and then melt-blended, extruded and granulated in a twin-screw basic granulator to obtain the fully biodegradable material;

[0013] Among them, the temperature setting of melt blending extrusion granulation is different from the common method of gradually heating from the feed hopper to the die, but innovatively adopts a method of gradually cooling from the feed hopper to the die, and the specific temperatures of each zone are room temperature (15-35°C) in zone 1, 195°C in zone 2, 195°C in zone 3, 190°C in zone 4, 185°C in zone 5, 185°C in zone 6, 180°C in zone 7, 175°C in zone 8, 170°C in zone 9, 165°C in zone 10, 160°C in zone 11, 155°C in zone 12, 150°C in zone 13, and 155°C in die. Otherwise, since the melting point difference between different types of biodegradable resins can be as high as 50°C, the low melting point resin component becomes a soft shell of the high melting point resin component after being quickly melted, resulting in the high melting point resin component not being completely melted and unable to be fully mixed with the anti-hydrolysis agent, and unable to achieve a good effect of delaying material aging.

[0014] Compared with the prior art, the fully biodegradable material provided by the present invention innovatively adds monomeric carbodiimide and polymeric carbodiimide to ordinary fully biodegradable resin. The composite anti-hydrolysis agent can convert the carboxyl groups and water molecules in the ordinary fully biodegradable resin into non-toxic urea compounds, thereby slowing down the hydrolysis rate of the material, but will not have a negative impact on the biodegradability of the composite material.

[0015] The invention can solve the problem that the existing common fully biodegradable materials have a short shelf life and cannot meet the needs of certain use fields for storage, transportation and sales with a longer shelf life, and maintains the biodegradability of the fully biodegradable materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The composting degradation test data of the samples prepared in Example 1 are shown. DETAILED DESCRIPTION

[0017] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0018] Embodiment 1:

[0019] This embodiment provides a fully biodegradable material, and the preparation method thereof comprises the following steps:

[0020] 10kg of PLA and 30kg of PBAT were weighed respectively, 80g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and 320g of polydivinylbenzene bonded 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide were added, the materials were mixed evenly by high-speed stirring in a high-speed mixer, and a special modified material was made by a twin-screw granulator. The specific temperature of each zone of the granulator was room temperature in zone 1, 195°C in zone 2, 195°C in zone 3, 190°C in zone 4, 185°C in zone 5, 185°C in zone 6, 180°C in zone 7, 175°C in zone 8, 170°C in zone 9, 165°C in zone 10, 160°C in zone 11, 155°C in zone 12, 150°C in zone 13, and 155°C at the die mouth, and the rotation speed was 300rpm. Then a film with a thickness of 50μm was made by a film blowing machine.

[0021] Figure 1 The composting degradation test data of the sample prepared in Example 1 is provided, and the test method is GB / T19277.1-2011. Figure 1 The standard reference material is microcrystalline cellulose.

[0022] Depend on Figure 1 It can be seen that during the composting degradation process of the sample in Example 1, the biodegradation rate can reach more than 90% at 145 days, which meets the requirements of "GB / T 41010-2021 Degradation Performance and Labeling Requirements for Biodegradable Plastics and Products".

[0023] Embodiment 2:

[0024] The specific preparation process is the same as that of Example 1, except that the amount of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide added is changed to 160 g, and the amount of polydivinylbenzene-bonded 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide added is changed to 640 g.

[0025] Embodiment 3:

[0026] The specific preparation process is the same as that of Example 1, except that the amount of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide added is changed to 40 g, and the amount of polydivinylbenzene-bonded 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide added is changed to 360 g.

[0027] Embodiment 4:

[0028] The specific preparation process is the same as that of Example 1, except that the amount of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide added is changed to 120 g, and the amount of polydivinylbenzene-bonded 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide added is changed to 280 g.

[0029] Embodiment 5:

[0030] The specific preparation process is the same as that of Example 1, except that the amount of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide added is changed to 160 g, and the amount of polydivinylbenzene-bonded 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide added is changed to 240 g.

[0031] Embodiment 6:

[0032] The specific preparation process is the same as that of Example 1, except that the addition amount of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide is changed to 200 g, and the addition amount of polydivinylbenzene-bonded 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide is changed to 200 g.

[0033] Comparative Example 1:

[0034] The specific preparation process is the same as that of Example 1, except that the addition amount of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and polydivinylbenzene-bonded 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide is changed to 0.

[0035] Comparative Example 2:

[0036] The specific preparation process is the same as that of Example 1, except that the amount of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide added is changed to 40 g, and the amount of polydivinylbenzene-bonded 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide added is changed to 160 g.

[0037] Comparative Example 3:

[0038] The specific preparation process is the same as that of Example 1, except that the addition amount of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide is changed to 0, and the addition amount of polydivinylbenzene-bonded 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide is changed to 400g.

[0039] Comparative Example 4:

[0040] The specific preparation process is the same as that of Example 1, except that the addition amount of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide is changed to 400 g, and the addition amount of polydivinylbenzene-bonded 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide is changed to 0.

[0041] Comparative Example 5:

[0042] The specific preparation process is the same as that of Example 1, except that the amount of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide added is changed to 240 g, and the amount of polydivinylbenzene-bonded 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide added is changed to 160 g.

[0043] Comparative Example 6:

[0044] The specific preparation process is the same as that of Example 1, except that the amount of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide added is changed to 280 g, and the amount of polydivinylbenzene-bonded 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide added is changed to 120 g.

[0045] Comparative Example 7:

[0046] The specific preparation process is the same as that of Example 1, except that the amount of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide added is changed to 320 g, and the amount of polydivinylbenzene-bonded 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide added is changed to 80 g.

[0047] Comparative Example 8:

[0048] The specific preparation process is the same as that of Example 1, except that the amount of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide added is changed to 360 g, and the amount of polydivinylbenzene-bonded 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide added is changed to 40 g.

[0049] The samples obtained in the above embodiments and comparative examples were tested according to GB / T 1040.1-2018 and GB / T 1040.2-2006. The test results are shown in Table 1.

[0050] Table 1

[0051]

[0052] As can be seen from Table 1, the sample of Example 1 maintains good mechanical properties after being subjected to high temperature and high humidity accelerated degradation treatment at 40°C and 93% humidity. By comparing the various embodiments and comparative examples, it can be seen that the reduction of monomeric carbodiimide will weaken the early performance retention rate of the material, while the reduction of polymeric carbodiimide will weaken the later performance retention rate of the material. For example, in Comparative Example 3, no monomeric carbodiimide was added, and the early performance retention rate of the resulting material was poor. When the monomeric carbodiimide and the polymeric carbodiimide are combined and the amount is within the preferred range of the present invention, the material exhibits a good mechanical property retention rate.

[0053] In Comparative Examples 5 to 8, although monomeric carbodiimide and polymeric carbodiimide are used in combination, and the total amount of the composite hydrolyzing agent is within the scope of the present invention, the specific ratio of the monomeric carbodiimide and the polymeric carbodiimide does not conform to the technical scheme of the present invention. Therefore, the mechanical properties of the fully biodegradable materials obtained are poor.

[0054] It can be seen that the present invention provides a fully biodegradable material with a long shelf life, which solves the problem that the existing ordinary fully biodegradable materials have a short shelf life and cannot meet the needs of certain use fields for storage, transportation and sales with a longer shelf life, and maintains the biodegradability of the fully biodegradable material.

Claims

1. A fully biodegradable material, characterized in that: It includes a fully biodegradable polymer matrix and a composite anti-hydrolysis agent; wherein the composite anti-hydrolysis agent includes monomeric carbodiimide and polymeric carbodiimide; the mass percentage of the composite anti-hydrolysis agent in the fully biodegradable material is 0.8-3%; the mass ratio of the monomeric carbodiimide to the polymeric carbodiimide is 5-50:50-95.

2. The fully biodegradable material according to claim 1, characterized in that: The material of the fully biodegradable polymer matrix includes one or a combination of two or more of polylactic acid, polybutylene adipate / terephthalate, polybutylene succinate-adipate, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), polycaprolactone, poly(3-hydroxybutyrate-co-4-hydroxybutyrate), polydioxanone, polybutylene succinate, polyglycolic acid, polypropylene carbonate, carbon dioxide / ethylene oxide copolymer, poly-3-hydroxybutyrate, poly(butylene succinate-terephthalate), starch, and cellulose.

3. The fully biodegradable material according to claim 1, characterized in that: The monomeric carbodiimide includes 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide.

4. The fully biodegradable material according to claim 1, characterized in that: The polymeric carbodiimide includes polydivinylbenzene bonded with 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide.

5. The fully biodegradable material according to claim 1, characterized in that: The mass percentage of the composite anti-hydrolysis agent in the fully biodegradable material is 0.8-2%.

6. The fully biodegradable material according to claim 5, characterized in that: The mass percentage of the composite anti-hydrolysis agent in the fully biodegradable material is 0.8-1.5%.

7. The fully biodegradable material according to claim 1, characterized in that: The mass ratio of the monomeric carbodiimide to the polymeric carbodiimide is 10-30:70-90.

8. The fully biodegradable material according to claim 7, characterized in that: The mass ratio of the monomeric carbodiimide to the polymeric carbodiimide is 20:

80.

9. A method for preparing a fully biodegradable material according to any one of claims 1 to 8, characterized in that: include: The fully biodegradable material is obtained by subjecting the fully biopolymer and the composite anti-hydrolysis agent to melt blending and then extruding and granulating.

10. The preparation method according to claim 9, characterized in that: The melt blending process is carried out in a twin-screw extruder granulator, and the temperatures in each zone from the feed hopper to the die are: Zone 1: 15-35℃, Zone 2: 195℃, Zone 3: 195℃, Zone 4: 190℃, Zone 5: 185℃, Zone 6: 185℃, Zone 7: 180℃, Zone 8: 175℃, Zone 9: 170℃, Zone 10: 165℃, Zone 11: 160℃, Zone 12: 155℃, Zone 13: 150℃, and die mouth: 155℃.

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