KR100912698B1 - Biodegradable thermoplastic composition comprising cellulose derivatives and basic inorganic fillers - Google Patents

Abstract

The present invention relates to a biodegradable resin composition comprising a cellulose derivative and a basic inorganic filler, and more particularly, by melting and processing a complex of a cellulose derivative and a basic inorganic filler, all of the biodegradability, processability and physical properties required for the biodegradable resin. Biodegradable resin composition, biodegradable moldings using the same, and a method of manufacturing the same, which can lower the manufacturing cost and effectively absorb acetic acid generated in the melt processing step, thereby preventing environmental pollution and increasing commerciality. It is about.

Cellulose derivative, basic inorganic filler, biodegradable, resin, melt processing

Description

Biodegradable thermoplastic composition comprising cellulose derivatives and basic inorganic fillers

The present invention relates to a biodegradable resin composition comprising a cellulose derivative and a basic inorganic filler, and more particularly, by melting and processing a complex of a cellulose derivative and a basic inorganic filler, all of the biodegradability, processability and physical properties required for the biodegradable resin. Biodegradable resin composition, biodegradable moldings using the same, and a method of manufacturing the same, which can lower the manufacturing cost and effectively remove acetic acid generated in the melt processing step of the basic inorganic filler, thereby improving the commercial environment. It is about.

In recent years, as white pollution increased due to the use of non-degradable synthetic polymers, interest in biodegradable packaging films and plastics made from renewable resources worldwide has increased. In order to solve the environmental pollution and petroleum depletion problems caused by waste plastics, biodegradable plastics made of renewable resources are in the spotlight, but incomplete degradability according to the surrounding environment and the price that is much higher than existing synthetic polymers must be solved. It is a problem to do. In order to reduce the high price of biodegradable plastics, studies have been actively conducted on the preparation of composites by blending biodegradable polymers with natural polymers such as relatively cheap and rich starch or inorganic fillers.

As biodegradable polymers, studies have been made on methods of preparing biodegradable resins using synthetic polymers such as polylactic acid (PLA) and polyhydroxyalkanoate (PHA). However, these polymers have disadvantages such as weak heat resistance and expensive compared to conventional general-purpose polymers. Cellulose, on the other hand, is the most abundant natural polymer present on earth, and is mainly composed of wood or cotton. Cellulose contains about 70% of crystal parts and has very good mechanical properties. However, the hydrogen bonding between the hydroxyl groups of the cellulose side chain has a high binding strength between the molecules and a high degree of crystallinity, which leads to problems in processing. Cellulose derivatives include cellulose nitrate (CN), cellulose acetate (CA), methyl cellulose (MC), which significantly reduce hydrogen bonding by substituting hydroxyl groups in cellulose repeat units by nitration, acetylation or etherification reactions. Ether cellulose (EC) and the like.

Among the cellulose derivatives, cellulose acetate is converted from cellulose to acetic acid esters, and is known to be biodegradable in nature, but there is a problem in that biodegradability is not good. That is, molded articles made of cellulose acetate maintain the original shape of the molded article for one to two years after being embedded in the soil, and a considerable time is required until the molded article is completely biodegraded. In addition, the molded article may be provided in landfill as waste, or may be left in a natural environment without being recovered as waste.

Therefore, research on the method which can improve the biodegradability of cellulose acetate is continued. Japanese Patent Laid-Open No. 6-199901 discloses a method for controlling the biodegradability of cellulose acetate by adding an acid compound having a higher acid dissociation constant than acetic acid to cellulose acetate, but the method adds an acid compound to cellulose acetate. At one point, the cellulose acetate chemically hydrolyzes under the influence of the acid compound, which produces acetic acid and gives a strong acetic acid odor to the cellulose acetate product.

In addition, cellulose diacetate (CDA) is an inexpensive and commercially important cellulose derivative. It is an organic ester-based natural material in which two hydroxyl groups in a molecule are substituted with an acetyl group (-OC (O) CH ₃ ), and is generally known as a raw material of acetate fiber. In general, CDA was mainly prepared by a solution processing method using acetone and the like. However, using the solution processing method, such as the re-recovery of the solvent and the cost of the product according to the additional process becomes expensive. Therefore, if it can be extruded and injected by converting it into a melt processing method, there is a possibility to replace the existing petroleum general purpose plastic. However, since CDA has higher glass transition temperature (Tg) and processability compared to general-purpose plastics, it is necessary to reduce the glass transition temperature to improve processability. Therefore, the reduction of the glass transition temperature and the melting temperature of the CDA is important, so a material for effective plasticization of the CDA is required. In addition, when processing CDA through high-temperature melt processing, acetyl groups in the side chain are decomposed to form acetic acid, resulting in poor workability and environmental pollution. The acetic acid odor remaining in the final product greatly reduces the value of the product. There is a risk of falling.

The use of inorganic fillers, on the other hand, improves the mechanical properties of thermoplastics such as heat distortion temperature, hardness, toughness, stiffness and mold shrinkage. It's a common way. Among inorganic fillers, calcium carbonate (CaCO ₃ ) is one of the cheapest inorganic particles commercially available and is widely used in many industrial products such as paints, inks, papers, plasticizers, and the like.

Therefore, there is a need for further research on biodegradable plastics using cellulose derivatives having excellent biodegradability and physical properties and inorganic fillers capable of improving physical properties.

The present invention has been made to solve the problems of the prior art as described above, an object of the present invention is to produce all of the biodegradability, processability and physical properties required for the biodegradable resin by producing a cellulose derivative and a basic inorganic filler composite through melt processing It is to provide a biodegradable resin composition, a biodegradable molded article using the same and a method for producing the same.

In order to achieve the above object, the present invention

It provides a biodegradable resin composition comprising a cellulose derivative and a basic inorganic filler comprising a repeating unit represented by the following formula (1).

[Formula 1]

Where

Each R independently represents H or -C (O) -X,

X represents an alkyl group having 1 to 4 carbon atoms, except that R is all hydrogen.

The present invention also provides a biodegradable molding comprising the resin composition having the above excellent biodegradability, processability and physical properties.

The invention also

i) providing a cellulose derivative comprising a repeating unit represented by Formula 1 below; And

ii) adding a basic inorganic filler to the cellulose derivative to knead it, and providing a method for producing a biodegradable molding comprising melt processing.

[Formula 1]

Where

Each R independently represents H or -C (O) -X,

X represents an alkyl group having 1 to 4 carbon atoms, except that R is all hydrogen.

The biodegradable resin composition according to the present invention significantly lowers the manufacturing cost by melt processing the cellulose derivative and the basic inorganic filler composite, and absorbs acetic acid, propionic acid generated in the melt processing step by adding the basic inorganic filler to effectively absorb the acetic acid odor. Removal, low melting point, easy to manufacture into a molding at low temperatures, and at the same time has the effect of having a significantly improved physical properties compared to conventional biodegradable moldings using starch.

EMBODIMENT OF THE INVENTION Hereinafter, the structure of this invention is demonstrated concretely.

The present invention relates to a biodegradable resin composition comprising a cellulose derivative and a basic inorganic filler comprising a repeating unit represented by the following formula (1).

[Formula 1]

Where

Each R independently represents H or -C (O) -X,

X represents an alkyl group having 1 to 4 carbon atoms, except that R is all hydrogen.

The biodegradable resin composition includes a cellulose derivative and a basic inorganic filler composite, wherein the basic inorganic filler absorbs acetic acid generated in the melt processing step. In addition, the basic inorganic filler is characterized by increasing the elastic modulus and glass transition temperature, the biodegradable resin composition is characterized in that the glass transition temperature is 106 to 114 ℃.

The cellulose derivative according to the present invention includes a repeating unit represented by the following Chemical Formula 1.

[Formula 1]

Where

Each R independently represents H or -C (O) -X,

X represents an alkyl group having 1 to 4 carbon atoms, except that R is all hydrogen.

Examples of the cellulose derivatives include cellulose acetate derivatives such as cellulose acetate, cellulose diacetate, or cellulose triacetate; Cellulose propionate derivatives such as cellulose propionate, cellulose dipropionate, or cellulose tripropionate; Cellulose butyrate derivatives such as cellulose butyrate, cellulose dibutylate, or cellulose tributylate; Cellulose acetate propionate derivatives; Or cellulose acetate butyrate etc. can be used individually or 2 types or more. Particularly preferably, one or more selected from the group consisting of cellulose acetate, cellulose diacetate, and cellulose triacetate can be used.

The cellulose derivative may be obtained from a waste tobacco filter which is a factor inducing environmental pollution. The cellulose derivative of the waste tobacco filter may be recycled to prepare a biodegradable resin composition, thereby significantly lowering the unit cost of the biodegradable resin composition and preventing environmental pollution. You can prevent it.

The cellulose derivative is preferably included in 50 to 90 parts by weight based on 100 parts by weight of the biodegradable resin composition. When the content is within the above range, both the processability of the biodegradable resin composition and the physical properties of the molded product can be satisfied.

In addition, the said cellulose derivative can use what was plasticized using the plasticizer.

The plasticizer improves the glass transition temperature (Tg), tensile strength, or Young's modulus of the cellulose derivative.

As the plasticizer, triacetin (TA), triethyl citrate (TEC), glycerin, or the like may be used alone or in combination of two or more thereof. More preferred plasticizer is triacetin.

The plasticizer is preferably included in an amount of 10 to 50 parts by weight with respect to 100 parts by weight of the biodegradable resin composition of the present invention, and if the content is in the above range, it is more preferable in the ease of molding and injection when forming the molding.

In addition, during the plasticization of the cellulose derivative, a lubricant (or a secondary plasticizer) may be additionally used to improve the processability of the cellulose derivative.

Preference is given to using epoxidized soybean oil (ESO) as the lubricant. In addition, latent heat catalysts can be used to cause ring-opening polymerization of epoxidized soybean oil.

The epoxidized soybean oil is preferably included 1 to 5 parts by weight with respect to 100 parts by weight of the biodegradable resin composition of the present invention, when the content is in the above range is better in improving the processability of the cellulose derivative.

In addition, the basic inorganic filler absorbs acetic acid generated during the melt processing of the cellulose derivative, and is characterized by improving physical properties of the biodegradable resin.

As the basic inorganic filler, carbonates of alkali metals such as calcium carbonate, magnesium carbonate and sodium carbonate, carbonates of alkaline earth metals, tricalcium phosphate, basic zeolite and the like can be used alone or in combination of two or more.

It is preferable that the said basic inorganic filler adds 10-50 weight part with respect to 100 weight part of biodegradable resin compositions of this invention. When the content is in the above range, the elastic modulus and glass transition temperature are increased in a concentration-dependent manner, which is better in the ease of molding and injection during molding. In addition, it is better to absorb the acetic acid generated during processing of the cellulose derivative to remove the smell of acetic acid.

In addition, the cellulose derivative and the basic inorganic filler are preferably mixed in a weight ratio of 5: 5 to 9: 1. When the content is within the above range, both the processability of the biodegradable resin composition and the physical properties of the molded product may be satisfied, and the basic inorganic filler may absorb acetic acid generated during melt processing to completely remove the odor.

The biodegradable resin composition of the present invention containing the above components may further include additives such as clay minerals such as montmorillonite and bentonite, decomposition accelerators or processing aids, if necessary, and the content thereof. Silver is preferably 0.1 to 10 parts by weight.

The clay mineral has an excellent hygroscopicity in a layered structure, and thus functions to make the molded product made of the biodegradable resin composition of the present invention excellently decomposed in water. In particular, the clay mineral is preferably montmorillonite.

In addition, when the clay mineral is used in the biodegradable resin composition of the present invention, it is preferable that the clay mineral is first mixed with a plasticizer and dispersed using an ultrasonic wave, and then added to the biodegradable resin composition.

The present invention also relates to a biodegradable molding comprising the resin composition according to the present invention having the above excellent biodegradability, processability and physical properties.

The biodegradable molding of the present invention prepared as described above is a film for semiconductor packaging, various containers, cups, spoons, forks, knives, toothbrushes, disposables such as straws, paper cups, paper coatings for manufacturing paper coatings, such as melt coating, mulching film, Agricultural and horticultural materials, such as seedling pots (plant pots), clips, medical devices, such as films / packaging for garbage bags, comfort bags, shrink films, packaging films, animal syringes, endoscope mouthpieces, hard biodegradation It can be used for modifiers of plastics, golf tees, fishing nets, fishing lines, bottles, stationery, and the like.

The invention also

i) providing a cellulose derivative comprising a repeating unit represented by Formula 1 below; And

ii) to a method for producing a biodegradable molding comprising the step of kneading and melt processing by adding a basic inorganic filler to the cellulose derivative.

[Formula 1]

Where

Each R is independently H or -C (O) -X Indicates,

X represents an alkyl group having 1 to 4 carbon atoms, except that R is all hydrogen.

The step i) is to provide a cellulose derivative, which can be synthesized or obtained from natural materials by various known methods.

Step i) preferably comprises the step of plasticizing the cellulose derivative by adding a plasticizer or a lubricant to the cellulose derivative.

At this time, the preferred content of each component is to add 50 to 90 parts by weight of cellulose derivative, 10 to 50 parts by weight of plasticizer and 1 to 5 parts by weight of lubricant.

Step ii) is a step of kneading the basic inorganic filler with the cellulose derivative or the plasticized composition provided in step i), followed by melt processing, for example, extrusion or injection. At this time, the cellulose derivative and the basic inorganic filler are preferably mixed in a weight ratio of 5: 5 to 9: 1.

The kneading and melt processing, for example, extrusion or injection may be applied to conventional methods of kneading, extruding and injecting the biodegradable resin composition, as an example, kneading may be performed using a batch mixer or the like. Extrusion may be used without limitation, such as a single screw or twin screw extruder.

Preferably, the kneading temperature is preferably 25 to 120 ° C, more preferably 25 to 100 ° C, because the melting point of cellulose diacetate is low.

In addition, after kneading at the above temperature, it can be molded into a molded article at a temperature of preferably 130 ~ 210 ℃ using a conventional extrusion or injection machine.

Hereinafter, preferred examples are provided to help understanding of the present invention, but the following examples are merely to illustrate the present invention, and the scope of the present invention is not limited to the following examples.

Example 1 Preparation of Cellulose Derivative and Basic Inorganic Filler (Calcium Carbonate) Composite

Cellulose derivatives such as cellulose diacetate [Mw. ca. 265.66 g · mol ^-1 , 55.9 wt% acetyl content, degree of substitution 2.46, manufactured by Celanese], and calcium carbonate (using a particle size of 3 μm of DongHo Calciuml) as a basic inorganic filler The complex was prepared. Triacetine (TA) was used as a plasticizer instead of synthetic synthetic products, and epoxidized soybean oil (ESO, Mw. 1000) used as a lubricant was purchased from Shindongsa.

Before preparing the composite of CDA / TA / ESO (composition 1) and CDA / CaCO ₃ / TA / ESO (composition 2), CDA and CaCO ₃ were each dried at 70 ° C. for 24 hours using a convection dryer.

After mixing for 1 minute in a supermixer at the ratio of CDA (70 parts by weight) / TA (30 parts by weight) / ESO (3 parts by weight) to prepare a mixture, 70 to prevent sufficient plasticization and water absorption of the mixture It was re-dried for 24 hours in a convection dryer.

CaCO ₃ in plasticized CDA (CDA (70 parts by weight) / TA (30 parts by weight) / ESO (3 parts by weight) mixture)) 10: 0 (composition 1), 9: 1, 8: 2, 7: After mixing at the ratio of 3, 6: 4, 5: 5 weight part, it injected | thrown-in to the twin screw extruder. The twin screw extruder used in this experiment was a BAU-TECH BT-19, a screw type 19mm and a modular twin screw extruder, which is an intermeshing corotating L / D 40. The combination of screws used is shown in FIG. 1. There are five mixing sections in total, and one reverse screw. In each section, CDA and CaCO ₃ are melted and mixed. The temperature gradient applied in this experiment was maintained at 130 ° C., 150 ° C., 170 ° C., 180 ° C., 180 ° C., 180 ° C., 190 ° C., and 210 ° C. from the hopper part to the die part, respectively, and the screw speed was constant at 150 rpm. The extrudate from the die was molded into pellets in a pelletizer through a cooling bath and dried in an 80 ° C convection oven for at least 24 hours.

(Production of specimen)

Tensile specimens according to ASTM D 1708 were made using a BAU-TECH mini-injector to measure the mechanical properties of pellets dried in a convection oven. The injection pressure was 900 psi, the cylinder temperature was 190 ° C and the circulation processing time was 3 minutes. The number of specimens was at least seven.

In order to confirm the kinetics of the mixture, a DMA analysis film (0.5 × 40 × 0.3mm) was produced for each composition by using CARVER's hydraulic press at a processing temperature of 180 ° C., a pressure of 1000 psi, and a circulation processing time of 5 minutes. .

In addition, the acetic acid absorption effects of CaCO ₃ were measured with a film made under the same conditions as the DMA analysis film. SEM was used to confirm the dispersibility of CaCO ₃ , and the film was prepared under the same conditions as the DMA analysis film, and then frozen in liquid nitrogen for 5 seconds and then broken.

(Physical analysis)

Dynamic mechanical analyzer, DMA (Seiko Exstar 6000, DMA / SS6100) was used to analyze the glass transition temperature and elastic modulus of the mixture. The temperature increase rate was carried out from 25 ℃ to 250 ℃ at 10 ℃ / min and a frequency of 1Hz was used under N ₂ atmosphere. Tension / Sinusoidal mode was used with a force of 200mN.

(Tension test)

To measure the tensile test, UTM (Universal Tensile Machine, LLOYD, Inc., LR 30K) was used to measure the mechanical properties at a load of 1 KN and a cross-head speed of 10 mm / min.

CDA / CaCO ₃ in order to determine the absorption effect of acetic acid by CaCO ₃ The composite film was immersed in boiling DI water and the pH value was measured using a pH meter.

SEM (Scanning Electron Microscopy, JEOL / JSM 7000F) was also used to observe the surface morphology of CaCO ₃ in CDA.

The composite was prepared by adding ESO as a plasticizer TA and a lubricant to the CDA, and CaCO ₃ was mixed therein to prepare a biodegradable complex successfully. The properties of these complexes according to the CaCO ₃ content were compared as follows.

Experimental Example 1 Dynamic Characteristics Analysis

The storage modulus and tan δ curve of the composite film prepared by adding 10, 30, and 50 parts by weight of CaCO ₃ to the composite of CDA / TA / ESO 7: 3: 0.3 ratio, respectively.

As shown in FIG. 2, these composite films do not show a glassy storage modulus having a constant value at room temperature, and thus are determined to be in the glass transition process. In loss modulus and tan δ, the glass transition temperature is increased and the glass transition temperature range is widened by CaCO ₃ added.

Comparing the storage modulus at room temperature, the higher the content of CaCO ₃ , the higher the value. This is generally observed in composites reinforced with inorganic materials. It is confirmed that the thermal strain temperature or room temperature modulus is increased by CaCO ₃ Can be.

In FIG. 3, the glass transition temperature of the composite film was observed from the tan δ curve. In general, the tan δ curve with temperature can be observed in the movement of small groups of polymer chains and the interfacial properties of heterogeneous materials. Therefore, the tan δ curve peak may change depending on the CaCO ₃ content in the system of the composite, and the transition may be observed by the plasticizer. The pure CDA film has a Tg point of approximately 195 ° C. while the plasticized CDA film has a Tg at 106 ° C. This is 89 ℃ lower than the Tg of pure CDA, it can be seen that TA acted as an effective plasticizer for CDA.

As shown in FIG. 3, as the CaCO ₃ content increases, the Tg increases from 106 ° C to 114 ° C, which can be seen as a result of interference with molecular motion as a CaCO ₃ filler during the transition process in the complex. have.

Experimental Example 2 Mechanical Property Analysis

Using the UTM, 10, 30, 50 parts by weight of CaCO ₃ was added to the composite of the ratio of CDA / TA / ESO 7: 3: 0.3 to measure the mechanical properties of the composite film. Table 1 compares the mechanical properties of the CDA plasticized with TA / ESO and the mechanical strength according to the CaCO ₃ content.

As shown in Table 1, TA / ESO plasticized CDA (Sample 1) showed a tensile strength of 62 MPa, an elastic modulus of 1,734 MPa, and an elongation of 7.2%. As CaCO ₃ content increased, tensile strength decreased and modulus of elasticity increased. As CaCO ₃ content increased to 50 parts by weight, the tensile strength decreased by 17.7% from 62 to 51MPa and the modulus of elasticity increased by 45.7% from 1734 to 3191MPa.

Lazzeri is CaCO ₃ / poly more propylene composite study the amount of CaCO ₃ increased from about the reported to increase resiliency of the composite material by the rigid nature of CaCO ₃ and, CaCO ₃ particles are aggregated to the tensile strength is reduced not to be made is distributed ( J. Appl . Polym . Sci. , 91, 925, 2004).

Further, according to chen studies were confirmation that the polyvinyl content of CaCO ₃ increase in chloride / CaCO ₃ composite has a tensile strength of the composite decreased, the amount of the microscale CaCO ₃ 10phr when, elongation is the highest, and the content of CaCO ₃ Is reported to decrease with increasing ( J. Polym . Sci . , 44, 451, 2006).

In the present invention, when the content of CaCO ₃ is 10 parts by weight, the elongation was increased by 29.4% compared with 7.2% elongation of the plasticized CDA to 10.2%, and showed a tendency to decrease as the content of CaCO ₃ increases. This is more the content of CaCO ₃ CaCO ₃ increases during processing in plasticized CDA And determines that the particles are aggregated without being dispersed, as the SEM image results in increasing the amount of CaCO ₃ was observed that the CaCO ₃ particle aggregation in CDA / CaCO ₃ complex.

No. CTE ^* (parts by weight) CaCO ₃ (parts by weight) Tensile Strength (MPa) % Elongation Young's modulus (MPa) One 100 0 62 7.2 1734 2 90 10 55 10.2 1756 3 80 20 54 9.6 1982 4 70 30 54 9.1 2349 5 60 40 53 7.9 2568 6 50 50 51 3.0 3191

*: The content of cellulose diacetate added with 30 parts by weight of TA and 3 parts by weight of ESO is shown.

Experimental Example 3 Fracture Surface Analysis

In general, the mechanical tensile strength of a composite is influenced by the shape of the composite microstructure. FIG. 4 is an SEM image of CDA / CaCO ₃ complexes (FIGS. 4B-D) complexes containing various CTEs (FIG. 4A) and CaCO ₃ . Each sample was made into a thin film using a hot presser, and then immersed in liquid nitrogen and broken to measure its cross section.

Looking at CTE733 containing no CaCO ₃ , it can be seen that the fracture surfaces are arranged in a constant direction (FIG. 4A). This is judged to be a phenomenon in which CDA molecules are arranged in a certain direction in the process of triacetin penetrating into the CDA molecule effectively, reducing the attraction between molecules and improving the flowability to make a film, and that triacetin is effective as a plasticizer for CDA. To show.

Dark holes can also be seen, which is believed to be the acetic acid of CDA generated during processing. As the content of CaCO ₃ increases, the SEM images of the composites show that the dark holes are filled away by the particles of CaCO ₃ (FIGS. 4B-D). This is considered to be a phenomenon in which CaCO ₃ absorbs acetic acid of CDA generated during processing, and the effect was confirmed by the change of pH (FIG. 5). As the content of CaCO ₃ increases in the composite (FIGS. 4b to d), the dispersion of the particles of CaCO ₃ worsens and agglomerates. Particularly, when the content of CaCO ₃ is 50 parts by weight, white CaCO throughout the CDA matrix is observed. It is confirmed that ₃ particles were encrusted and covered. This is CaCO ₃ It is believed that the particles decrease the tensile strength and elongation because they reduce the attraction between the CDA molecules.

Experimental Example 4 Absorption Effect of Acetic Acid

CDA / CaCO ₃ Acetic acid is generated between CDA and TA during the preparation of the complex. CDA / CaCO ₃ when the composite body from being heated was immersed in CDA / CaCO ₃ complex of deionized water (DI water) film to find out about the effect of the acetic acid absorption CaCO _3, to measure the pH change of the de-ionized water over time.

In the case of plasticized CDA without CaCO ₃ in FIG. 5 (CaCO ₃ 0 parts by weight) As time passes, the pH of the deionized water changes to acidic. This means that heating the film releases the acetic acid owned by the CDA, and acetic acid emissions can be a problem when commercialized as a product. As the content of CaCO ₃ increases, the change in pH decreases, and almost no change occurs when the content of CaCO ₃ is 50 parts by weight. This means that CaCO ₃ absorbs acetic acid, and the absorption of acetic acid was also confirmed by SEM image (FIG. 4).

Example 2 Preparation of Cellulose Derivative and Basic Inorganic Filler (zeolite) Composite

CaCO ₃ as basic inorganic filler A composite was prepared in the same manner as in Example 1, except that zeolite was used instead. The pH change of the deionized water was measured according to the method of Experimental Example 4 for the complex. The zeolite was added in an amount of 50 parts by weight based on 50 parts by weight of CDA.

<Example 3> Preparation of cellulose derivative and basic inorganic filler (tricalcium phosphate, Ca ₃ (PO ₄ ) ₂ ) composite

CaCO ₃ as basic inorganic filler Instead, tricalcium phosphate (Ca ₃ (PO ₄ ) ₂ ) except that the composite was prepared in the same manner as in Example 1. The pH change of the deionized water was measured according to the method of Experimental Example 4 for the complex. At this time tricalcium phosphate (Ca ₃ (PO ₄ ) ₂ ) was added in an amount of 50 parts by weight based on 50 parts by weight of CDA.

As shown in FIG. 5, the pH of the deionized water did not turn acidic but increased slightly over time. In other words, zeolite and tricalcium phosphate (Ca ₃ (PO ₄ ) ₂ ) was found to have a better acetic acid absorption effect than calcium carbonate.

Comparative Example 1 Preparation of Cellulose Derivative, Acidic Inorganic Filler, and NaHCO ₃ Composite

A composite was prepared in the same manner as in Example 1, except that NaHCO ₃ was used as the inorganic filler.

Comparative Example 2 Preparation of Cellulose Derivative, Acidic Inorganic Filler, and KHCO ₃ Composite

A composite was prepared in the same manner as in Example 1, except that KHCO ₃ was used as the inorganic filler.

However, the composites prepared in Comparative Examples 1 and 2 were discolored upon extrusion and could not be processed (not shown).

1 shows a screw configuration used in the present invention.

Figure 2 shows the storage modulus of cellulose diacetate / calcium carbonate (CDA / CaCO ₃ ) composites by calcium carbonate content.

Figure 3 shows the change in tan δ curve ( Tg ) of the CDA / CaCO ₃ complex by calcium carbonate content.

Figure 4 is a SEM photograph showing the fracture surface of the CDA / CaCO ₃ composite by calcium carbonate content.

Figure 5 shows the pH value of the CDA / CaCO ₃ complex by calcium carbonate content, and the pH value of the CDA / zeolite complex and CDA / tricalcium phosphate (Ca ₃ (PO ₄ ) ₂ ) complex.

Claims (20)

Cellulose derivative comprising a repeating unit represented by the formula (1); And A biodegradable resin composition comprising at least one basic inorganic filler selected from the group consisting of carbonates of alkali metals, carbonates of alkaline earth metals, tricalcium phosphate and basic zeolites: [Formula 1]

Where Each R independently represents H or -C (O) -X, X represents an alkyl group having 1 to 4 carbon atoms, except that R is all hydrogen. The method of claim 1, Biodegradable resin composition, characterized in that the cellulose derivative is at least one selected from the group consisting of cellulose acetate, cellulose diacetate, and cellulose triacetate. The method of claim 1, Biodegradable resin composition, characterized in that the cellulose derivative is contained in 50 to 90 parts by weight based on 100 parts by weight of the biodegradable resin composition. The method of claim 1, Biodegradable resin composition, characterized in that the biodegradable resin composition further comprises 10 to 50 parts by weight of a plasticizer. The method of claim 4, wherein The plasticizer is at least one member selected from the group consisting of triacetin (TA), triethyl citrate (TEC) and glycerin. The method of claim 1, Biodegradable resin composition, characterized in that the biodegradable resin composition further comprises 1 to 5 parts by weight of lubricant. The method of claim 6, Biodegradable resin composition, characterized in that the lubricant is epoxidized soybean oil. delete The method of claim 1, Biodegradable resin composition, characterized in that the basic inorganic filler is contained in 10 to 50 parts by weight based on 100 parts by weight of the biodegradable resin composition. The method of claim 1, Biodegradable resin composition, characterized in that the weight ratio of the cellulose derivative and the basic inorganic filler is 5: 5 to 9: 1. The method of claim 1, Biodegradable resin composition, characterized in that the biodegradable resin composition further comprises one or more selected from the group consisting of clay minerals, decomposition accelerators and processing aids. The biodegradable molded article manufactured by kneading and melt-processing the biodegradable resin composition in any one of Claims 1-7 and 9-11. The method of claim 12, Biodegradable moldings are semiconductor packaging films, containers, cups, spoons, forks, knives, toothbrushes, straws, paper cups, paper coatings for papermaking, mulching films, seedling pots (plants), clips, garbage bags, comfort bags, Biodegradable, characterized in that it is any one selected from the group consisting of shrink film, packaging film, animal syringe, endoscope mouthpiece, modifier of hard biodegradable plastic, golf tee, fishing net, fishing line, bottles and stationery Moldings. i) providing a cellulose derivative comprising a repeating unit represented by Formula 1 below; And ii) a biodegradable molding comprising kneading and melt processing by adding at least one basic inorganic filler selected from the group consisting of carbonates of alkali metals, carbonates of alkaline earth metals, tricalcium phosphate and basic zeolites to the cellulose derivative Manufacturing method of:  [Formula 1]

Where Each R independently represents H or -C (O) -X, X represents an alkyl group having 1 to 4 carbon atoms, except that R is all hydrogen. The method of claim 14, Step i) comprises the step of plasticizing the cellulose derivative by adding 10 to 50 parts by weight of plasticizer and 1 to 5 parts by weight of lubricant to 50 to 90 parts by weight of the cellulose derivative. The method of claim 15, The cellulose derivative is a method for producing a biodegradable molding, characterized in that the cellulose derivative is at least one selected from the group consisting of cellulose acetate, cellulose diacetate, or cellulose triacetate. The method of claim 15, The plasticizer is at least one member selected from the group consisting of triacetin (TA), triethyl citrate (TEC) and glycerin. The method of claim 15, A method for producing a biodegradable molding, characterized in that the lubricant is epoxidized soybean oil. delete The method of claim 14, A weight ratio of the cellulose derivative and the basic inorganic filler is 5: 5 to 9: 1.

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