A low-cost degradable plastic bottle and preparation method thereof

Abstract

The present application discloses a method for preparing a low-cost degradable plastic bottle, characterized in that the method comprises the following steps: step a, weighing 20-30 parts of polylactic acid, 20-30 parts of polyurethane elastomer for mixing, and adding 0.5-5 parts of plasticizer; step b, weighing 20-30 parts of alginic acid, 10-20 parts of nano calcium carbonate, and 0.2-10 parts of dispersant; wherein alginic acid is blended with nano calcium carbonate to obtain an additive; step c, adding the mixed material in the step b to step a, obtaining a degradable plastic bottle system, mixing well and extruding at 170-200°C using a twin-screw extruder, and finally performing blow molding to obtain a degradable plastic bottle. This method reduces the amount of polylactic acid and polyurethane elastomer, and the overall amount of polylactic acid used can be reduced by 15-20%; the amount of polyurethane elastomer used can be reduced by 15-20%; and the production cost is even lower.

Description

Technical Field

[0001] The present application relates to a degradable plastic material, in particular to a low-cost degradable plastic bottle and a preparation method thereof. Background Art

[0002] Polylactic acid is a fully degradable material with good transparency and mechanical properties. Its production process is pollution-free and it has been widely used in plastic products. However, in the production of polylactic acid plastic bottles, aging will occur during their use, and the cost of this type of plastic bottle is also relatively high.

[0003] Sodium alginate is a natural polysaccharide extracted from seaweed. It is biodegradable, has good conductivity and excellent biocompatibility.

[0004] In the prior art, publication number CN113769175B discloses a composition containing sodium alginate and polylactic acid, and its preparation method and application, which belongs to the field of medical device technology, and includes the following components in percentage by weight: 1-99% of absorbable polylactic acid material and 1-99% of sodium alginate gel. The technical solution provided by the present invention can inhibit the degradation rate of polylactic acid material in a water environment, and then provide a pre-canned gel injection product clinically, so that when used clinically, medical staff can avoid the re-dissolution operation before use, and can be used directly, thereby reducing or even avoiding adverse reactions such as subcutaneous nodules caused by aggregation of polylactic acid particles. It is mainly used in the medical field, and all of them are used to prepare gel materials. This material is difficult to use in the plastic field.

[0005] The invention patent of the prior application publication number CN109438944B of the applicant also discloses the use of seaweed fiber for reinforcing polylactic acid materials. Specifically, a seaweed fiber composite reinforced degradable plastic bottle and its preparation method, comprising the following components by weight: 40-50 parts of polylactic acid, 30-40 parts of polyurethane elastomer, 10-25 parts of mesoporous SiO2 / seaweed fiber, 0.5-1.5 parts of plasticizer, and 0.8-2 parts of dispersant. The plastic bottle prepared by the present invention is green and environmentally friendly, biodegradable, and the bio-based polyurethane elastomer synthesized from renewable biomass resources has good degradability and biocompatibility, improves the mechanical properties of polylactic acid, and the seaweed fiber has the effect of releasing far infrared and negative ions, which can promote human metabolism, while releasing minerals and vitamins to make the body healthy. For the preparation of the plastic bottle, it is mainly an improvement in function, but the cost of the plastic bottle is high.

[0006] The present invention aims to solve the problems in the prior art and to provide a low-cost polylactic acid plastic that can use alginate, and to prepare the plastic into a plastic bottle. Summary of the invention

[0007] Based on the problem of high cost of preparing plastic bottles in the prior art and by the company, the present invention proposes to reduce the preparation cost of plastic bottles while ensuring the light transmittance, durability, strength and other effect requirements of the plastic bottles.

[0008] Based on this, one of the concepts of the present application is to provide a low-cost biodegradable plastic bottle and a method for preparing the same, which uses more inorganic substances to add to the polylactic acid system to reduce the amount of polylactic acid used, thereby reducing costs.

[0009] Specifically, in a low-cost biodegradable plastic bottle and a preparation method thereof provided by the present disclosure, nano calcium carbonate is used as an additive to reduce the use of polylactic acid, thereby reducing costs.

[0010] Furthermore, another concept of the present disclosure is to provide a low-cost biodegradable plastic bottle and a method for preparing the same, wherein more polysaccharide solution is added to the polylactic acid system to reduce the amount of polylactic acid used, thereby reducing costs.

[0011] Specifically, the present invention uses nano-alginate to be added into a polylactic acid system, so that sodium alginate is dispersed in the polylactic acid system, thereby reducing the cost of polylactic acid plastic bottles.

[0012] Specifically, the present disclosure provides a polylactic acid plastic system, which specifically includes 20-30 parts of polylactic acid, 20-30 parts of polyurethane elastomer, 20-30 parts of alginate, 10-20 parts of nano calcium carbonate, 0.5-5 parts of plasticizer, and 0.2-10 parts of dispersant.

[0013] Compared with the applicant's previous solution, the polylactic acid plastic system formula disclosed in the present invention can reduce the amount of polylactic acid used by 15-20%;

[0014] The polylactic acid plastic system formula disclosed in the present invention can reduce the amount of polyurethane elastomer used by 15-20%;

[0015] Furthermore, in order to ensure that the polylactic acid plastic system can be smoothly formed, the present disclosure performs pre-treatment on the nano-calcium carbonate, specifically preparing polylactic acid and alginate that can smoothly fix the plastic viscosity system.

[0016] Furthermore, the calcium carbonate processing method comprises the following steps:

[0017] Step S1: preparing an acrylic acid solution, adding the acrylic acid solution into the calcium carbonate slurry, and heating and stirring;

[0018] Step S2: Add calcium chloride solution to step S1, add surfactant at the same time, control the pore formation, and heat and stir.

[0019] Step S3: filtering, washing, and baking the solid in step S2 to obtain nanoporous calcium carbonate.

[0020] In some embodiments, the mass ratio of the acrylic acid solution to the calcium carbonate in step S1 is 1:20-30.

[0021] Furthermore, the concentration of the calcium carbonate slurry in step S1 is 10-20%.

[0022] Furthermore, the heating and stirring temperature in step S1 is 70-90° C., and the stirring time is 1-3 h.

[0023] In some embodiments, the amount of calcium chloride added in step S2 is 1-5% of the reaction solution.

[0024] Furthermore, the surfactant is sodium dodecyl sulfonate and / or sodium dodecyl sulfate;

[0025] Further, the dosage of the surfactant is 0.1-0.5;

[0026] In some embodiments, the baking temperature in step S3 is 140-180°C, preferably 140-150°C.

[0027] Furthermore, the baking time is 1-3h.

[0028] The present invention uses nano porous calcium carbonate material in the raw material. The porous calcium carbonate material can fix polysaccharides on the one hand, and can better bond with polylactic acid and polyurethane elastomer on the other hand, thereby improving the overall performance of the plastic.

[0029] Furthermore, the alginate disclosed in the present invention is pre-blended with nanoporous calcium carbonate to obtain a blended powder.

[0030] Specifically, the alginate powder is dispersed in an ethanol solution and stirred with a homogenizer to obtain a homogeneous dispersion of the alginate powder. During the dispersion process, porous calcium carbonate is added, and then the solution is filtered and dried.

[0031] Wherein, the stirring speed of the homogenizer is greater than 10000r / min.

[0032] The present invention creatively uses a homogenizer. First, alginate is dispersed in an ethanol solution using the homogenizer. Since ethanol has a small specific surface area, the alginate can be dispersed relatively evenly with high-speed stirring. After calcium carbonate is added, the porous structure of calcium carbonate has an adsorption effect on alginate during the homogenization and stirring process, and fine alginate particles can be adsorbed into the porous structure of calcium carbonate.

[0033] Furthermore, after the alginate and the nanoporous calcium carbonate are blended, they are dried at a temperature of 80-90° C. for a drying time of 1-5 hours.

[0034] Specifically, in some embodiments, the present disclosure provides a method for preparing a low-cost degradable plastic bottle, comprising the following steps:

[0035] Step a, weighing 20-30 parts of polylactic acid and 20-30 parts of polyurethane elastomer, mixing them, and adding 0.5-5 parts of plasticizer;

[0036] Step b, weighing 20-30 parts of alginic acid, 10-20 parts of nano calcium carbonate, and 0.2-10 parts of a dispersant; wherein the alginic acid and the nano calcium carbonate are blended to obtain an additive.

[0037] Step c, adding the mixed material in step b into step a to obtain a degradable plastic bottle system, mixing evenly, extruding at 170-200° C. using a twin-screw extruder, and finally blow molding to obtain a degradable plastic bottle.

[0038] The main benefits of this disclosure are reflected in the following aspects:

[0039] 1. The present invention reduces the usage of polylactic acid and polyurethane elastomer, and can reduce the usage of polylactic acid by 15-20% and the usage of polyurethane elastomer by 15-20% as a whole; the production cost is lower.

[0040] 2. The present invention uses porous calcium carbonate materials in the system and cooperates with alginic acid to reduce costs. The porous structure is used in the production process, and the alginic acid is adsorbed during the homogenization and stirring process, and the alginic acid fine particles can be adsorbed into the porous structure of calcium carbonate. On the other hand, it can better bond with polylactic acid and polyurethane elastomer to improve the overall performance of the plastic. DETAILED DESCRIPTION

[0041] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] According to the present invention, a method for preparing a low-cost degradable plastic bottle is disclosed, comprising the following steps:

[0043] Step a, weighing 20-30 parts of polylactic acid and 20-30 parts of polyurethane elastomer, mixing them, and adding 0.5-5 parts of plasticizer;

[0044] Wherein, the amount of polylactic acid can be 20 parts, 25 parts, or 30 parts;

[0045] The amount of the polyurethane elastomer can be 20 parts, 25 parts, or 30 parts;

[0046] The amount of the plasticizer can be 0.5 parts, 1 part, 3 parts, or 5 parts;

[0047] Furthermore, the mixture of the polylactic acid and the polyurethane elastomer can ensure good mixing uniformity after adding the plasticizer.

[0048] In some embodiments, the present invention provides a method for preparing a low-cost biodegradable plastic bottle, which also includes step b, weighing 20-30 parts of alginate, 10-20 parts of nano-calcium carbonate, and 0.2-10 parts of a dispersant; wherein the alginate and the nano-calcium carbonate are blended to obtain an additive.

[0049] Furthermore, the alginate is nano alginate, and the nano calcium carbonate is nano porous calcium carbonate;

[0050] The preparation method of the nanoporous calcium carbonate comprises the following steps:

[0051] Step S1: preparing an acrylic acid solution, adding the acrylic acid solution into the calcium carbonate slurry, and heating and stirring;

[0052] Specifically, the mass ratio of the acrylic acid solution to the calcium carbonate in step S1 is 1:20-30. The mass ratio of the acrylic acid solution to the calcium carbonate can be 1:20, 1:25 or 1:30.

[0053] Furthermore, the concentration of the calcium carbonate slurry in step S1 is 10-20%.

[0054] Furthermore, the heating and stirring temperature in step S1 is 70-90° C., and the stirring time is 1-3 h.

[0055] In some embodiments, the preparation of nano-calcium carbonate as nano-porous calcium carbonate further includes step S2: adding calcium chloride solution to step S1, adding surfactant at the same time, controlling pore formation, heating and stirring.

[0056] Furthermore, the amount of calcium chloride added in step S2 is 1-5% of the reaction solution.

[0057] Furthermore, the surfactant is sodium dodecyl sulfonate and / or sodium dodecyl sulfate;

[0058] Further, the dosage of the surfactant is 0.1-0.5;

[0059] In some embodiments, the preparation of nano-calcium carbonate as nano-porous calcium carbonate further includes step S2: filtering, washing, and baking the solid in step S2 to obtain nano-porous calcium carbonate.

[0060] The baking temperature in step S3 is 140-180°C, preferably 140-150°C.

[0061] Furthermore, the baking time is 1-3h.

[0062] In some embodiments, alginate is pre-blended with nanoporous calcium carbonate to obtain a blended powder.

[0063] Specifically, the alginate powder is dispersed in an ethanol solution and stirred with a homogenizer to obtain a homogeneous dispersion of the alginate powder. During the dispersion process, porous calcium carbonate is added, and then the solution is filtered and dried.

[0064] Wherein, the stirring speed of the homogenizer is greater than 10000r / min.

[0065] In some embodiments, the present invention provides a method for preparing a low-cost degradable plastic bottle, which also includes step c, adding the mixture in step b to step a to obtain a degradable plastic bottle system, mixing evenly and extruding it at 170-200°C using a twin-screw extruder, and finally blow molding to obtain a degradable plastic bottle.

[0066] The corresponding table of the specific embodiment is as follows:

[0067] According to the preparation method in the above embodiment, a low-cost degradable plastic bottle is used, and the degradable plastic bottle is prepared according to the method of steps ac, which also includes preparing nanoporous calcium carbonate using the method according to steps S1-S3.

[0068]

[0069] Further, the porous calcium carbonate used in Examples 1-5 is prepared or obtained in one batch. In addition, in Examples 1-5, alginic acid is used to be blended with nanoporous calcium carbonate in advance to obtain a blended powder. Specifically, the alginic acid powder is dispersed in an ethanol solution and stirred using a homogenizer to obtain a homogenous dispersion of the alginic acid powder, and porous calcium carbonate is added during the dispersion process, followed by filtering and drying. The stirring speed of the homogenizer is greater than 10000r / min.

[0070] In the specific examples, Example 6 was also carried out, wherein Example 6 was carried out according to the formula of Example 5, but the difference was that the alginate powder and the porous calcium carbonate were directly added to step a without being subjected to homogenous blending treatment.

[0071] From the appearance, the blending of Example 2 and Example 6 will show obvious unevenness, and the light transmittance of the obtained plastic bottles is not uniform. It can be seen that when both polylactic acid and polyurethane elastomer are reduced, the method of adding fillers is not improved, and the obtained products are unqualified.

[0072] Among them, Example 1 can obtain a transparent plastic bottle, and Examples 3-5 can also obtain qualified transparent plastic bottles. From the perspective of production cost, Example 5 has the lowest cost, and compared with the applicant's previous production process, the production cost can be reduced by 10-15%.

[0073] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for preparing a low-cost biodegradable plastic bottle, characterized in that: The steps include: Step a, weighing 20-30 parts of polylactic acid and 20-30 parts of polyurethane elastomer, mixing them, and adding 0.5-5 parts of plasticizer; Step b, weighing 20-30 parts of alginic acid, 10-20 parts of nano calcium carbonate, and 0.2-10 parts of a dispersant; wherein the alginic acid and the nano calcium carbonate are blended to obtain an additive; The alginic acid powder described in step b is dispersed in an ethanol solution and stirred with a homogenizer to make the alginic acid powder uniformly dispersed, and nano calcium carbonate is added during the dispersion process, followed by filtering and drying; Step c, adding the mixed material in step b to step a to obtain a degradable plastic bottle system, mixing evenly, extruding at 170-200° C. using a twin-screw extruder, and finally blow molding to obtain a degradable plastic bottle; The alginate in step b is nano-alginate, and the nano-calcium carbonate is nano-porous calcium carbonate; The preparation method of the nanoporous calcium carbonate comprises the following steps: Step S1: preparing an acrylic acid solution, adding the acrylic acid solution into the calcium carbonate slurry, and heating and stirring; Step S2: adding calcium chloride to step S1, adding a surfactant at the same time, controlling the pore formation, heating and stirring; Step S3: The solid in step S2 is filtered, washed, and baked to obtain nanoporous calcium carbonate; The mass ratio of the acrylic acid solution to the calcium carbonate in step S1 is 1:20-30; The concentration of the calcium carbonate slurry in step S1 is 10-20%; The heating and stirring temperature in step S1 is 70-90°C, and the stirring time is 1-3h; The amount of calcium chloride added in step S2 is 1-5% of the reaction solution.

2. A method for preparing a cost-effective biodegradable plastic bottle as claimed in claim 1, characterized in that: The surfactant is sodium dodecyl sulfonate and / or sodium dodecyl sulfate.

3. A method for preparing a cost-effective biodegradable plastic bottle as claimed in claim 2, characterized in that: The baking temperature in step S3 is 140-150°C; The baking time is 1-3h.

4. A method for preparing a cost-effective biodegradable plastic bottle as claimed in claim 3, characterized in that: The stirring speed of the homogenizer is greater than 10000r / min.

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