PREPARATION METHOD OF FULLY DEGRADABLE POLYGLYCOLIC ACID COMPOSITE PACKAGING MATERIALS

Abstract

The present disclosure provides a fully degradable Polyglycolic acid (PGA) composite packaging material comprises, by weight part, the following: PGA, polycaprolactone, poly(L-lactide--caprolactone), anti-blocking agent, slipping agent, flexibilizer, waterproofing agent, chitosan, reinforced fibers and the like. The present disclosure further provides a preparation method of the fully degradable modified polyglycolic acid composite packaging materials. The present disclosure has the following advantages. The packaging material of the present disclosure has good microbial degradation and hydrolysis. With complete biodegradation, it would result in end-products, water and carbon dioxide, which are environmentally friendly, non-toxic and pose no threat to human- and animal-health. The packaging material of the present disclosure has good mechanical properties, and can fully meet various application requirements of packaging materials. Inexpensive and environmental pollution-free fillers can be added without influence on mechanical properties. The cost can be effectively reduced. The preparation process is simple.

Claims

1. A fully degradable polyglycolic acid composite packaging material, comprising, by weight parts, the following: TABLE-US-00006 polyglycolic acid 80-100, anti-blocking agent 0.2-1, slipping agent 0.05-2, flexibilizer 1-7, waterproofing agent 0.5-11

2. The fully degradable polyglycolic acid composite packaging material according to claim 1, further comprising, by weight parts, the following: TABLE-US-00007 polycaprolactone 45-60, poly (L-lactide--caprolactone) 2-5, pentaerythritol diphosphite 0.03-0.2, chitosan 2-6, starch 15-35, reinforced fiber 1-5

3. The fully degradable polyglycolic acid composite packaging material according to claim 1, wherein the poly(L-lactide--caprolactone) has a weight-average molecular weight of 200,000-500,000, and has -caprolactone units in a mole percentage of 20-25%.

4. The fully degradable polyglycolic acid composite packaging material according to claim 1, wherein the anti-blocking agent is flake graphite, talcum powder, diatomite or silicon dioxide.

5. The fully degradable polyglycolic acid composite packaging material according to claim 1, wherein the flexibilizer is DuPont Biomax Strong from E.I. DuPont Company, or a composite flexibilizer which is made of nano-calcite, nano-talcum powder and subnano fatty acid rare-earth salt in a weight ratio of 30-50:10-20:1-5.

6. The fully degradable polyglycolic acid composite packaging material according to claim 1, wherein the waterproofing agent is an animal- or plant-waterproofing agent, wherein the animal waterproofing agent is one or more of beeswax, beef tallow, whale oil, lanocerin or spermaceti, and the plant waterproofing agent is one or more of palm wax, peanut oil, castor-oil plant, palmitic acid, soybean oil, epoxidized soybean oil, bayberry wax, jojoba oil or hydrogenated vegetable oil.

7. The fully degradable polyglycolic acid composite packaging material according to claim 1, wherein the slipping agent is oleamide, stearamide or erucyl amide.

8. The fully degradable polyglycolic acid composite packaging material according to claim 1, wherein the reinforced fiber is one or more of wood-, linen-, cotton- or bamboo-fiber.

9. A method for preparing the fully degradable polyglycolic acid composite packaging material according to claim 1, comprising the following steps: (1) crushing polyglycolic acid, polycaprolactone and poly(L-lactide--caprolactone) into particles with an average particle size of 50-100 m, and mixing well to obtain a mixed main ingredient; (2) adding the anti-blocking agent, slipping agent, flexibilizer, waterproofing agent, pentaerythritol diphosphite, chitosan, starch and reinforced fiber, then grinding, milling, and mixing well to obtain a mixed accessory ingredient; and (3) mixing the main ingredient and the accessory ingredient well, and performing press molding with a temperature of 160-190 C., a time of 1-8 minutes and a pressure of 5-20 Mpa to make a sheet of 0.3-4 mm, or extruding with an extruder at an extruding temperature of 180-220 C. to obtain a film.

10. The method for preparing the fully degradable polyglycolic acid composite packaging material according to claim 9, wherein an ultrasonic wave treatment is introduced into the process of press molding and film-tape casting with an extruder, and wherein the ultrasonic wave treatment is performed with a power of 400-800 W and a frequency of 50-150 KHz.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] The present disclosure will be described in detail below in combination with the following specific embodiments.

[0032] Preferably, a fully degradable PGA composite packaging materials comprises, by weight parts:

TABLE-US-00003 PGA 80-100 polycaprolactone 50-55 poly (L-lactide--caprolactone) 3-4 anti-blocking agent 0.5-0.8 slipping agent 0.2-0.8 flexibilizer 3-5 waterproofing agent 2-8 pentaerythritol diphosphite 0.05-0.1 chitosan 3-4 starch 20-30 reinforced fibers 2-4

[0033] A method for preparing the fully degradable PGA composite packaging materials, comprises following steps:

[0034] (1) crushing PGA, polycaprolactone and/or poly(L-lactide--caprolactone) into particles with an average particle size of 6080 m in a low-temperature ultrafine grinder, and mixing well to obtain a mixed main ingredient;

[0035] (2) adding the anti-blocking agent, slipping agent, flexibilizer, waterproofing agent, pentaerythritol diphosphite, chitosan, starch and reinforced fibers, then grinding and crushing to obtain particles with an average particle size of 60-80 m, and mixing well to give a mixed accessory ingredient;

[0036] (3) mixing the main ingredient and accessory ingredient well, and performing press molding at a temperature of 170-180 C. and a pressure of 5-12 Mpa for 1-3 minutes, to obtain sheets of 0.3-4 mm; or, extruding a cast or inflation film by an extruder at a temperature of 190-220 C. This film is made of fully biodegradable PGA composite materials. An ultrasonic treatment may be introduced into the process of press molding and film-tape casting with an extruder, and be performed with power of 500-700W and frequency of 60-140 KHz. The various components can make effective intermigration under the action of ultrasonic wave, so as to form a tight structure, improve toughness and strength, and have better transparency.

[0037] Preferably, in the above step (3), the above mixture can be placed in a mold, and then be press molded at a temperature of 185 C. and at a pressure of 10 Mpa for 3 minutes. Alternatively, the cast or inflation film can be extruded by the extruder at a temperature of 120 C. to make PGA film, in which, the ultrasonic power is 550 W and the frequency is 100 KHz. Concussion stirring can be effectively performed with acoustic wave. Meanwhile, it can avoid too strong acoustic wave which may lead to cavitation effect producing bubbles. The ultrasonic wave may be generated by an ultrasonic wave-generating generating device which is fixed to an outer panel in a wall-adhering manner, and be transferred to the materials in the cavity through a side wall.

[0038] The following tables show the specific embodiments of the fully degradable PGA composite packaging materials of the present disclosure and the experimental test data thereof. Further, the mechanical properties such as tensile strength and breaking elongation are tested according to the method of GB/T4456-1996. Other performance parameters are tested by corresponding existing standards. The expression Fully Degradation as defined in the tables means the number of days for the resulting materials being fully biological and environmental degradation, which can be done under the action of a degradation accelerator. The degradation accelerator may be a low molecular weight of PGA (molecular weight being less than 5000). See table 1 and table 2 for details.

TABLE-US-00004 TABLE 1 Examples 1-6 of the fully degradable polyglycolic acid (PGA) composite packaging materials. Table 1. Ex. 1-6 of the fully degradable PGA composite packaging materials. Components by Weight Parts Ingredients Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 PGA 100 95 90 85 95 80 Flake Graphite 0 0 0 0 0 1 Oleamide 1 Erucyl Amide 1 1 Composite Flexibilizer 4 7 DuPont 4 4 Lanocerin 3 2 2 Whale Oil 5 3 3 3 Epoxidized Soybean 5 Oil Palm Wax 6 Tensile Strength, MPa 215 218 283 275 286 298 Breaking Elongation, % 23 22 43 45 44 46 Bending Strength, MPa 121 124 188 192 196 191 Fully Degradation/days 25 27 28 27 26 29

[0039] In the above table, DuPont means DuPont Biomax Strong from E.I. Du Pont Company.

TABLE-US-00005 TABLE 2 Examples 7-12 of the fully degradable polyglycolic acid (PGA) composite packaging materials. Table 2. Ex. 7-12 of the fully degradable PGA composite packaging materials. Components by Weight Parts Ingredients Ex. 7 Ex. 8 Ex. 9 Ex. 10 Ex. 11 Ex. 12 PGA 92 81 95 90 85 96 polycaprolactone 54 46 59 50 55 53 Poly(L-lactide-- 3.3 3 4.5 3.5 4 3 caprolactone) Anti-blocking agent Silicon Dioxide 0.5 0.7 08 Flake Graphite 0.3 0.9 0.6 Slipping agent Stearamide 0.8 1.9 1.5 Oleamide 0.06 Erucyl Amide 1 1.2 Flexibilizer DuPont 2.5 2 4 Composite 6 3 5 Flexibilizer Waterproofing Agent Lanocerin 3 2 3 2 Whale Oil 0.6 3 3 2 Palm Wax 3 2 2 Soybean Oil 2 3 2 Pentaerythritol 0.04 0.15 0.08 0.12 0.09 0.18 Diphosphite Chitosan 2.5 3 5.5 4 5 4 Starch 21 16 34 20 2 30 Reinforced Fibers Fibrilia 4.5 3 3.5 Bamboo Fiber 2 4 Wood Fiber 2.5 Tensile Strength, MPa 310 331 346 355 350 323 Breaking Elongation, % 92 91 105 96 102 99 Bending Strength, MPa 235 242 248 229 238 239 Fully Degrade/days 33 32 31 33 32 34

[0040] In the above table, DuPont means DuPont Biomax Strong from E.I. Du Pont Company.

[0041] The poly(L-lactide--caprolactone) used herein can be obtained by putting L-lactide and -caprolactone in toluene in a molar ratio of 75:25, under the catalysis of stannous octoate, drying at 40 C., 133 Pa for 24 hours, and then lowering the pressure to less than 0.5 Pa to melt and copolymerize under a constant temperature. This present disclosure can, with a small addition number of poly(L-lactide--caprolactone), significantly improve the mechanical properties such as elongation and elastic strength of PGA, without changing the biodegradability thereof.

[0042] PGA is mainly be obtained by the polycondensation of glycolic acid, glycolic acid ester, glycolide and other raw materials under the action of catalysts. At present, glycolic acid can be produced by the hydrogenation and hydrolysis of an intermediate product, dimethyl oxalate, in an ethylene glycol project. PGA with excellent performance can be obtained at very low cost, in the rapid scale promotion of coal-based ethylene glycol.

[0043] As can be seen from the above examples, the fully degradable PGA composite packaging materials of the present disclosure have excellent mechanical properties, as well as good microbial degradation and hydrolysis. Besides, the materials and preparation process have low cost, and thus can effectively replace the existing plastic packaging materials.

[0044] The above are only preferred embodiments of the present disclosure, and are not intended to limit the scope of the present disclosure. That is, simple equivalent changes and modifications made within the scope of present disclosure and the contents cited herein, are still fall in the scope of the present disclosure.