KR100531677B1 - Preparing method of biodegradable resin composition and biodegradable resin composition produced by this method - Google Patents

Abstract

The present invention relates to a method for producing a biodegradable resin composition in which a polycarbonate is mixed with a polylactic acid-based polymer and fine colloidal silica is added. Thus, when the plastic case is disposed of, the biodegradable polylactic acid is decomposed well to prevent environmental pollution. Carbonates improve impact resistance and include fine colloidal silica to improve gloss and wear resistance on surfaces. It is used as injection molding for cell phone cases or high-quality plastic products with short life cycles.

Description

Preparation method of biodegradable resin composition and biodegradable resin composition and biodegradable resin composition produced by this method

Entering the information age, the reality of the convenience of the telephone and the development of science and technology, the use of the mobile phone has become a daily life of individuals for more convenient and faster communication. As a result, new products are being released all the time and their functionality has been rapidly developed. These fast and short life cycles increase the amount of waste used and remain a social end.

By the way, the mobile phone is required to have the basic characteristics that can have impact resistance and beautiful appearance, but biodegradable and improved impact resistance when aliphatic polyester or polyester carbonate is added to the polylactic acid for helmet use (Japanese Patent Laid-Open No. 2000- 109663), but its wear resistance and gloss were inferior in application to mobile phones and high-end image electronic products.

The present invention is to provide a biodegradable resin composition for use in plastic case, battery case, and the like for a cell phone using a resin containing polycarbonate and microsilica in polylactic acid to solve the above problems and a method of manufacturing the same.

The present invention relates to a biodegradable resin composition and a method of manufacturing the same, 10 to 50 weight of polycarbonate for improving the impact resistance against 100 parts by weight of polylactic acid-based polymer to solve the environmental pollution problem when using the mobile phone case In order to mix the parts and to improve the glossiness and abrasion resistance of the mobile phone surface, a biodegradable resin composition containing 200 to 20000 ppm of colloidal silica having an average particle diameter of 20 to 100 nm is prepared. Furthermore, there is a characteristic in that it is intended to manufacture injection molded articles used in cell phone cases.

The polylactic acid polymer is a blend of poly L-lactic acid and poly D-lactic acid, and at least a part of the carboxyl end of the poly L-lactic acid and / or poly D-lactic acid is blocked. 10,000 or more polylactic acid resin composition.

The polycarbonate needs to be mixed in an amount of 10 to 50 parts by weight based on 100 parts by weight of a polylactic acid polymer, preferably 15 to 30 parts by weight, and when the content is less than 10 parts by weight, the impact resistance drops sharply and exceeds 50 parts by weight. There is a problem that the biodegradability falls sharply.

Colloidal silica is present in aqueous solution and has an average particle diameter in the range of 20 to 100 nm. If it is smaller than 20 nm, coagulation occurs to inhibit dispersibility. The addition amount can be added to 200 ~ 20000ppm, but less than 200ppm sharply decreases the glossiness, when more than 20000ppm both wear resistance and glossiness drops sharply.

In the method for producing an injection molded article using the biodegradable resin composition of the present invention, the mixture may be introduced into a hopper of an injection molding machine, and may be melted and molded at a temperature range of 100 to 200 ° C., but is higher than 200 ° C. or a residence time of 2 minutes. In the case of an abnormality, moldability falls rapidly. If the temperature is lower than 40 ° C, the work efficiency during molding is lowered. Firstly, blending and pelletizing with an extruder and molding in an injection molding machine results in better dispersibility and uniformity.

In addition to this configuration, it is also possible to add additional additives or make various modifications. Examples include similar materials such as antioxidants, glass fibers, pigments, colorants, antistatic agents, mold release agents, plasticizers, antibacterial agents, nucleating agents and the like.

In order to improve processability, an aliphatic polyester or an aliphatic polyester containing an aliphatic carboxylic acid and an aromatic carboxylic acid may be added.

The present invention is beautiful in appearance and wear-resistant, so it can be applied to the body of the electrical and electronic products, in particular to a mobile phone.

The following examples and comparative examples further illustrate the invention but do not limit the scope of the invention. First, the measurement and evaluation methods necessary for the explanation of the present invention were performed under the following conditions.

(1) Wear resistance:

A specimen width of 13 mm and a length of 150 mm are fixed to a friction measuring machine (HEIDON), and 200 times are performed at a speed of 300 mm / min based on the amount of powder attached to the surface of the knife.

No powder at all: 0, slight; △, a large amount of occurrence: expressed as ×.

(2) Glossiness (ASTM D 523)

 A method of measuring the reflectance of the surface of a product of light,

      100 or more: 0, 100-80: (triangle | delta) and 80 or less were represented by x.

 (3) Exploded View (KS M-3100-1)

Compute the test material under the same conditions using TLC grade cellulose with a particle size of 20 µm or less as the standard sample, and calculate the biodegradability of the test material from the cumulative amount of carbon dioxide released for 45 days (using the formula below). When calculating the biodegradability of the test substance in contrast to

    More than 90%: 1, 51% ~ 89%: 2, 50% or less: 3.

Dt = [(CO2) _T- (CO2) _B / ThCO2] × 100

(CO2) _T : Accumulated amount of carbon dioxide from the container containing the test substance

(CO2) _B : Accumulated amount of carbon dioxide from containers containing compost

           ThCO2: Calculation of Theoretical Carbon Dioxide

ThCO2 = M _TOT × C _TOT × (44/12)

M _TOT : Total dry solids (g) of test substance added at the beginning of the analysis

C _TOT : percentage of organic carbon in the total dry solids of the test substance (g / g)

     44,12: molecular weight of carbon dioxide and atomic weight of carbon

(Example 1)

As polylactic acid, 500 ppm of microsilica having 10 wt% of polycarbonate and 50 nm of average particle diameter was mixed with 100 parts by weight of PLA resin of Cargill dow Co., Ltd., and prepared in pellet form using an extruder. The obtained pellet was sufficiently dehumidified and dried in an injection mold to prepare an injection specimen having a width of 2 cm 0.5 cm and a length of 10 cm at 80 ° C. for 1 minute. The fabricated wear resistance and the degree of decomposition were measured, and the results are shown in Table 1.

(Example 2)

Except for using the polycarbonate 30wt% injection molded specimens were prepared in the same manner as in Example 1, the wear resistance, the degree of decomposition was measured, the results are shown in Table 1.

 (Example 3)

Except for using the polycarbonate 50wt% injection molded specimens were prepared in the same manner as in Example 1, and the wear resistance, the degree of decomposition was measured, and the results are shown in Table 1.

(Example 4)

Extrusion specimens were prepared in the same manner as in Example 1, except that 20 wt% of polycarbonate and 200 ppm of fine silica having an average particle diameter of 50 nm were prepared, and wear resistance and gloss were measured, and the results are shown in Table 2.

(Example 5)

Extrusion specimens were prepared in the same manner as in Example 4 except that 1000 ppm of microsilica having an average particle diameter of 50 nm was measured, and abrasion resistance and glossiness were measured, and the results are shown in Table 2.

(Example 6)

 Extrusion specimens were prepared in the same manner as in Example 4, except that 5000 ppm of microsilica having an average particle diameter of 50 nm was measured, and abrasion resistance and gloss were measured, and the results are shown in Table 2.

(Example 7)

 Extrusion specimens were prepared in the same manner as in Example 4, except that 20000 ppm of fine silica having an average particle diameter of 50 nm was measured, and wear resistance and gloss were measured. The results are shown in Table 2.

(Example 8)

 The moldability was measured in the same manner as in Example 1 except that the molding temperature was molded at 60 ° C. for 1 minute, and the results are shown in Table 3.

(Example 9)

 The moldability was measured in the same manner as in Example 1 except that the molding temperature was formed at 120 ° C. for 1 minute, and the results are shown in Table 3.

(Comparative Example 1)

As polylactic acid, 500 ppm of fine silica having an average particle diameter of 50 nm was mixed with the PLA resin of Cargill dow Co., Ltd., and then pelletized using an extruder. The obtained pellets were sufficiently dehumidified and dried in an injection mold to produce injection specimens having a width of 2 cm and 0.5 cm and a length of 10 cm at a temperature of 80 to 100 ° C. The prepared specimens were measured for wear resistance and degradability, and the results are shown in Table 1.

(Comparative Example 2)

Except for using PBS (Poly Butylene Succinate) -based aliphatic polyester alone, an injection specimen was prepared in the same manner as in Comparative Example 1, and the wear resistance and degradability were measured, and the results are shown in Table 1.

(Comparative Example 3)

Extrusion specimens were prepared in the same manner as in Example 4 except that the gel-type silica having an average particle diameter of 2.0 μm was used at 5000 ppm. The abrasion resistance and gloss were measured, and the results are shown in Table 2.

(Comparative Example 4)

Extrusion specimens were prepared in the same manner as in Example 4, except that 5000 ppm of calcium carbonate having an average particle diameter of 0.6 μm was measured. The abrasion resistance and gloss were measured, and the results are shown in Table 2.

(Comparative Example 5)

The moldability was measured in the same manner as in Example 1 except that the molding temperature was formed at 200 ° C. for 1 minute, and the results are shown in Table 3.

Table-1

Wear resistance Degradable Example 1 △ One Example 2  ○ 2 Example 3  ○ 3 Comparative Example 1  × One Comparative Example 2  × One

Table-2

Luster Wear resistance Example 4 △ △ Example 5  ○  ○ Example 6  ○  ○ Example 7 △  ○ Comparative Example 3  ×  × Comparative Example 4 △ △

Table-3

Formability Example 8  ○ Example 9 △ Comparative Example 5  ×

The present invention as described above is applied to injection molded articles of biodegradable materials, such as a mobile phone case or a high-quality plastic products short life cycle can be prevented from being decomposed during use and environmental pollution. It also has impact resistance and can impart wear resistance and gloss to the surface.

Claims (6)

A method for producing a biodegradable resin composition comprising 10 to 50 parts by weight of polycarbonate and 200 to 20000 ppm of colloidal silica mixed with 100 parts by weight of polylactic acid polymer. The method for producing a biodegradable resin composition according to claim 1, wherein the polylactic acid polymer is composed of L-lactic acid, D-lactic acid or L, D-lactic acid, and has a molecular weight of 10,000 or more. The method of producing a biodegradable resin composition according to claim 1, wherein the colloidal silica has an average particle diameter of 20 to 100 nm. The method of claim 1, wherein the biodegradable resin composition is prepared by injection molding at a molding temperature of 60 to 200 ° C. The method of claim 4, wherein the injection shape in the injection molding step is a mobile phone case or a battery case. Biodegradable resin composition prepared by the method of claim 1.