Biodegradable composition for preparing table-ware, mulching film and package and method for preparing the same

Abstract

The present invention relates to a biodegradable composition for the preparation of table-ware, mulching film and package, which comprises: 2-6% by weight of starch; 35-45% by weight of plant powders; 20-30% by weight of calcium carbonate; 2-7% by weight of sorbital; 7-13% by weight of polypropene; 2-5% by weight of polyethylene; 2-6% by weight of coupling agent; 1-2% by weight of defoamer; 2-5% by weight of stearic acid; 2-6% by weight of stearate; 3-6% by weight of glycerine or epoxidized soybean oil; and 60-100 ppm photosensitizer. The present invention also relates to a method for preparing the composition, which comprises: treating a plant wastes with a diluent acid, drying and pulverizing, then mixing it with starch, polypropene, and polyethylene, sorbital, defoamer, coupling agent, stearic acid, stearate, glycerine and photosensitizer homogeneously; blending the mixture obtained in a double-screw extruder at a temperature of 160-180 C to obtain the composition of the present invention.

Description

FIELD OF THE INVENTION

[0001] The present invention relates to a biodegradable composition and a method for preparing the same, especially to a biodegradable composition for the preparation of tableware, drink container, mulching film and package, and a method for preparing the same.

BACKGROUND OF THE INVENTION

[0002] With the development of the modem industry, especially the rapid development of the petroleum chemical engineering, a lot of synthetic resins and plastic articles with good properties and low costs have been provided for the industrial and agricultural production and our daily life. The use of plastic film, foamed plastic articles (for example, package materials, etc) and plastic sheets in many fields has greatly promoted the industrial and agricultural productions and enriched people's daily life. However, the plastic wastes after use are abandoned everywhere, such as ground, rivers, mountains, streets and parks, which pollutes the environment seriously and produces one of the most harmful environmental pollution called “white pollution” and therefore draws extensive attentions. In recent years, more and more countries make laws to restrict the use of plastic films and foamed plastics. At the same time, great efforts are made to develop various kinds of degradable resins and plastic articles.

[0003] In addition, with the acceleration of the living rhythm, snack foods are many people's favor more and more. Snack foods need a lot of tableware and drink containers. In the past, the tableware and drink containers for snack foods are mainly made of foamed plastics, which are harmful to human body and the environment at high temperatures, and therefore are prohibited to use any more. In order to solve these problems, people has tried to substitute paper tableware and drink containers for plastic ones for snack foods. However, the paper tableware and drink containers for snack foods have the disadvantages of more complex production procedures and higher costs. It is also tried to solve these problems by using plastics material and modified starch to produce the tableware and drink containers for snack foods, but this kind of tableware and drink containers have the disadvantages of lower biodegradability, higher costs and possible secondary pollution.

[0004] Similarly, plastic films, foamed plastic articles (for example, package materials, etc) and plastic sheets (extruded sheet products) have the same problems as mentioned above.

OBJECTS OF THE INVENTION

[0005] One object of the present invention is to overcome the disadvantages of the prior art and to provide a biodegradable composition, especially a biodegradable composition for the preparation of tableware, drink containers, mulching films and packages.

[0006] Another object of the present invention is to provide a method for preparing the biodegradable composition, especially a method for preparing the biodegradable composition for the preparation of tableware, drink containers, mulching films and packages.

THE BRIEF DESCRIPTION OF THE DRAWING

[0007] FIG. 1 shows the flow chart of the method of the present invention for preparing the biodegradable composition for the preparation of tableware, drink containers, mulching films and packages.

SUMMARY OF THE INVENTION

[0008] According to one aspect of the invention, it provides a biodegradable composition for the preparation of tableware, drink containers, mulching films and packages, which comprises:

[0009] 2-6% by weight of starch;

[0010] 35-45% by weight of plant powders;

[0011] 20-30% by weight of calcium carbonate;

[0012] 2-7% by weight of sorbital;

[0013] 7-13% by weight of polypropene;

[0014] 2-5% by weight of polyethylene;

[0015] 2-6% by weight of coupling agent;

[0016] 1-2% by weight of defoamer;

[0017] 2-5% by weight of stearic acid;

[0018] 2-6% by weight of stearate;

[0019] 3-6% by weight of glycerine; and

[0020] 60-100 ppm photosensitizer.

[0021] According to another aspect of the present invention, it provides a method for preparing the biodegradable composition for the preparation of tableware, drink containers, mulching films and packages, which comprises:

[0022] (1) treating one or more plant wastes selected from the group consisting of sugar cane residue, peanut shell, dry pine needle, rice husk, millet bran and soybean shell in a 0.2-1.0% by weight of sulfuric acid or hydrochloric acid solution for 2-10 hours to degrease and modify and to wash, and then drying the same to let it have a water content of less than 10%; mixing the obtained plant wastes with starch, sorbital, polypropene, and polyethylene, and pulverizing the obtained mixture to obtain a powder with a particle size of larger than 70 mesh; mixing the obtained powder with calcium carbonate, stearic acid, stearate, coupling agent, defoamer, glycerine or epoxidized soybean oil, and photosensitizer homogeneously;

[0023] (2) blending the mixture obtained in step(1) in a double-screw extruder at a temperature of 160-180 C to obtain the composition of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0024] With the increasing care for the environment, the demand for biodegradability of plastic articles, such as tableware, drink containers, mulching films and packages, is higher and higher. The present invention provides a biodegradable composition for the preparation of tableware, drink containers, mulching films and packages, which comprises:

[0025] 2-6% by weight of starch;

[0026] 35-45% by weight of plant powders;

[0027] 20-30% by weight of calcium carbonate;

[0028] 2-7% by weight of sorbital;

[0029] 7-13% by weight of polypropene;

[0030] 2-5% by weight of polyethylene;

[0031] 2-6% by weight of coupling agent;

[0032] 1-2% by weight of defoamer;

[0033] 2-5% by weight of stearic acid;

[0034] 2-6% by weight of stearate;

[0035] 3-6% by weight of glycerine or epoxidized soybean oil; and

[0036] 60-100 ppm photosensitizer.

[0037] According to the composition of the present invention, it preferably comprises:

[0038] 3-5% by weight of starch;

[0039] 35-40% by weight of plant powders;

[0040] 20-30% by weight of calcium carbonate;

[0041] 4-6% by weight of sorbital;

[0042] 8-11% by weight of polypropene;

[0043] 3-4% by weight of polyethylene;

[0044] 3-5% by weight of coupling agent;

[0045] 1-2% by weight of defoamer;

[0046] 3-4% by weight of stearic acid;

[0047] 3-5% by weight of stearate;

[0048] 3-5% by weight of glycerine or epoxidized soybean oil; and

[0049] 60-100 ppm photosensitizer.

[0050] According to the composition of the present invention, it more preferably comprises 3% by weight of starch; 37% by weight of plant powders; 25% by weight of calcium carbonate; 5% by weight of sorbital; 9% by weight of polypropene; 3% by weight of polyethylene; 5% by weight of coupling agent; 4% by weight of stearic acid; 4% by weight of stearate; 1% by weight of defoamer; 4% by weight of glycerine and 60 ppm photo sensitizer.

[0051] According to the composition of the present invention, the starch includes corn starch, potato starch, ipomoea batatas starch, cassava starch and their modified starch with a grain size of larger than 70 mesh.

[0052] According to the composition of the present invention, the plant powder is the powder of one or more plants in sugar cane residue, peanut shell, dry pine needle, rice husk, millet bran and soybean shell.

[0053] According to the composition of the present invention, the calcium carbonate is light or heavy calcium carbonate with a grain size of larger than 70 mesh.

[0054] According to the composition of the present invention, the coupling agent is that known by the skilled person in the art, and is preferably silane.

[0055] According to the composition of the present invention, the photosensitizer is that known by the skilled person in the art, and is preferably benzophenone.

[0056] According to the composition of the present invention, the defoamers are those known by the skilled person in the art, and is preferably emulsified silicone oil.

[0057] According to the composition of the present invention, the stearate is ferrite stearate, magnesium stearate or calcium stearate, and is preferably ferrite stearate.

[0058] According to another aspect of the invention, there provides a method for preparing the biodegradable composition for the preparation of table-ware, mulching film and package, which comprises:

[0059] (1) treating one or more plant wastes selected from the group consisting of sugar cane residue, peanut shell, dry pine needle, rice husk, millet bran and soybean shell in a 0.2-1.0% by weight of sulfuric acid or hydrochloric acid solution for 2-10 hours to degrease and modify and to wash, and then drying the same to let it have a water content of less than 10%; mixing the obtained plant wastes with starch, sorbital, polypropene, and polyethylene, and pulverizing the obtained mixture to obtain a powder with a particle size of larger than 70 mesh; mixing the obtained powder with calcium carbonate, stearic acid, stearate, coupling agent, defoamer, glycerine or epoxidized soybean oil, and photosensitizer homogeneously;

[0060] (2) blending the mixture obtained in step(1) in a double-screw extruder at a temperature of 160-180 C to obtain the composition of the present invention.

[0061] According to the method of the present invention, the starch includes corn starch, potato starch, ipomoea batatas starch, cassava starch and their modified starch with a grain size of larger than 70 mesh.

[0062] According to the method of the present invention, the plant powder is the powder of one or more plants in sugar cane residue, peanut shell, dry pine needle, rice husk, millet bran and soybean shell.

[0063] According to the method of the present invention, the calcium carbonate is light or heavy calcium carbonate with a grain size of larger than 70 mesh.

[0064] According to the method of the present invention, the coupling agent is that known by the skilled person in the art, and is preferably silane.

[0065] According to the method of the present invention, the photosensitizer is that known by the skilled person in the art, and is preferably benzophenone.

[0066] According to the method of the present invention, the defoamers are those known by the skilled person in the art, and is preferably emulsified silicone oil.

[0067] According to the method of the present invention, the stearate is ferrite stearate, magnesium stearate or calcium stearate, and preferably ferrite stearate.

[0068] The composition of the present invention can be widely used in various plastic articles, such as plastic film, foamed plastic articles(for example, package materials, etc), plastic sheets, the tableware and drink containers for snack foods and so on. When it is used in different kinds of plastic articles, the dosage and the selection of other kinds of materials are known to the skilled in the art. For example, when it is used to prepare plastic films such as agricultural film or package, the plastic ingredient is usually polyethylene. The ratio of plastic ingredient and composition of the present invention can vary between 30˜70:70˜30 by weight according to the requirement of the final product. Similarly, when it is used to prepare extruded sheets, foamed plastic articles and the tableware and drink containers for snack foods, the plastic ingredient is usually polypropylene. The ratio of plastic ingredient and composition of the present invention can vary between 30˜70:70˜30 by weight according to the requirement of the final product.

[0069] The composition of the present invention can excellently improve the biodegradability of plastic articles. The final product prepared with the composition and plastic ingredient such as polyethylene and polypropylene, for example, plastic films such as agricultural film or package, extruded sheets, foamed plastic articles, and the tableware and drink containers for snack foods, can be fully biodegraded in 4-5 month under the natural conditions.

[0070] The method and device to prepare the final product, which is prepared with the composition and plastic ingredient such as polyethylene and polypropylene, are well known to the skilled in the art and not described in detail.

[0071] The present invention will be described in further detail with the following examples, which should not be taken as the limitation of the invention. If it is not specified clearly, the dosages of the ingredients are by weight.

EXAMPLES1

[0072] FIG. 1 shown the flow chart of the procedures for preparing the biodegradable composition for the preparation of table-ware, drink containers, mulching film and package of the present invention.

[0073] Sugar cane residue was soaked in a 0.8% by weight of sulfuric acid solution for 5 hours. The mixture was filtered to obtain a processed sugar cane residue, and then was dried to have a water content of less than 10% by weight. The mixture of 37 parts by weight of the obtained sugar cane residue, 3 parts by weight of starch, 25 parts by weight of light calcium carbonate, 5 parts by weight of sorbitol, 3 parts by weight of polyethylene, and 9 parts by weight of polypropene was pulverized in a pulverizer to obtain a powder of the mixture having a grain size of larger than 70 mesh.

[0074] The powder of the mixture as obtained above was mixed with 4 parts by weight of the glycerine, 1 parts by weight of emulsified silane oil, 5 parts by weight of silane, 4 parts by weight of stearic acid, 4 parts by weight of ferrite stearate, and 60 ppm benzophenone homogeneously to obtain a mixture of the same. The obtained mixture was blended and extruded and pelleted in a double-screw extruder at a temperature of 170 C to obtain a concentrate of the composition of the present invention. The obtained concentrate was mixed with polypropene at a weight ratio of 500:50 homogeneously, and the mixture was molded in a mould for the preparation of table-ware. After being kept at a temperature of 35 C in the mould for 2 hours, a table-ware having good biodegradability was obtained.

[0075] The table-ware obtained above could be fully biodegraded in 4-5 month under the natural conditions.

EXAMPLES 2-5

[0076] In a similar manner as described in Example 1, the biodegradable compositions for the preparation of table-ware, mulching film and package of the present invention were prepared. The contents of the raw materials in theses examples were listed in the following Table. 1 Example 2 Example 3 Example 4 Example 5 Starch 3 3 3 3 Sorbitol 4 4 5 4 Sugar cane residue 15  — — 13  powder Peanut shell powder 18  15  — — Powder of dry pine — 18  — — needle Millet bran powder 5 4 15 — Soybean shell powder — — 10 10  Rice husk powder — — 13 15  Light calcium carbonate 27  27  — — Heavy calcium carbonate — — 26  26  Stearic acid 3 4 3 4 Ferrite stearate 4 5 4 5 Polyethylene 3 3 4 3 Polypropene 9 8 8 9 Glycerine 4 — — 4 epoxidized soybean oil — 4 4 — Silane 4 4 4 3 Emulsified silicon oil 1 1 1 1 benzophenone 60 ppm 60 ppm 60 ppm 60 ppm

[0077] The compositions obtained in Examples 2-5 were mixed with polypropene or polyethylene respectively, and the obtained mixtures were used to prepare table-ware, mulching film and package by the technology known by the person skilled in the art, respectively.

[0078] The table-ware, drink containers, mulching film and package obtained above could be fully biodegraded in 4-5 month under the natural conditions.

INDUSTRIAL APPLICABILITY

[0079] The composition of the present invention could be used to prepare various plastic articles, for example, to prepare various table-wares, snack containers, agricultural films, packages, extruded sheets and plastic packages. These articles could be fully biodegraded in 4-5 month under the natural conditions. Therefore, the environment pollution by light plastic articles could be eliminated or greatly alleviated.

Claims

1. A biodegradable composition for the preparation of table-ware, drink containers, mulching film and package, comprising:

2-6% by weight of starch;

35-45% by weight of plant powders;

20-30% by weight of calcium carbonate;

2-7% by weight of sorbital;

7-13% by weight of polypropene;

2-5% by weight of polyethylene;

2-6% by weight of coupling agent;

1-2% by weight of defoamer;

2-5% by weight of stearic acid;

2-6% by weight of stearate;

3-6% by weight of glycerine or epoxidized soybean oil; and

60-100 ppm photosensitizer.

2. The composition according to claim 1, comprising:

3-5% by weight of starch;

35-40% by weight of plant powders;

20-30% by weight of calcium carbonate;

4-6% by weight of sorbital;

8-11% by weight of polypropene;

3-4% by weight of polyethylene;

3-5% by weight of coupling agent;

1-2% by weight of defoamer;

3-4% by weight of stearic acid;

3-5% by weight of stearate;

3-5% by weight of glycerine or epoxidized soybean oil; and

60-100 ppm photosensitizer.

3. The composition according to claim 2, comprising: 3% by weight of starch; 37% by weight of plant powders; 25% by weight of calcium carbonate; 5% by weight of sorbital; 9% by weight of polypropene; 3% by weight of polyethylene; 5% by weight of coupling agent; 4% by weight of stearic acid; 4% by weight of stearate; 1% by weight of defoamer; 4% by weight of glycerine or epoxidized soybean oil and 60 ppm photosensitizer.

4. The composition according to claim 1, 2 or 3, wherein the starch includes corn starch, potato starch, ipomoea batatas starch, cassava starch and their modified starch with a grain size of larger than 70 mesh.

5. The composition according to claim 1, 2 or 3, wherein, the plant powder is the powder of one or more plants in sugar cane residue, peanut shell, dry pine needle, rice husk, millet bran and soybean shell.

6. The composition according to claim 1, 2 or 3, wherein, the calcium carbonate is light or heavy calcium carbonate with a grain size of larger than 70 mesh.

7. The composition according to claim 1, 2 or 3, wherein, the coupling agent is silane.

8. The composition according to claim 1, 2 or 3, wherein, the stearate is ferrite stearate, magnesium stearate or calcium stearate.

9. The composition according to claim 1, 2 or 3, wherein, the stearate is ferrite stearate.

10. The composition according to claim 1, 2 or 3, wherein, the photosensitizer is benzophenone.

11. The composition according to claim 1, 2 or 3, wherein, the defoamer is emulsified silicone oil.

12. A method for preparing a biodegradable composition for the preparation of table-ware, mulching film and package, comprising:

(1) treating one or more plant wastes selected from the group consisting of sugar cane residue, peanut shell, dry pine needle, rice husk, millet bran and soybean shell soaked in a 0.2-1.0% by weight of sulfuric acid or hydrochloric acid solution for 2-10 hours to degrease and modify and to wash, and then drying the same to let it have a water content of less than 10%; mixing the obtained plant wastes with starch, sorbital, polypropene, and polyethylene, and pulverizing the obtained mixture to obtain a powder with a particle size of less than 70 mesh; mixing the obtained powder with calcium carbonate, stearic acid, stearate, coupling agent, defoamer, glycerine or epoxidized soybean oil and photosensitizer homogeneously;

(2) blending the mixture obtained in step(1) in a double-screw extruder at a temperature of 160-180 C to obtain the composition of the present invention.