Patent Publication Number: US-2015073075-A1

Title: Biodegradable resin composition containing eco-friendly plasticizer, and biodegradable resin product using the same

Description:
TECHNICAL FIELD 
     The present invention relates to a technique for preparing a biodegradable resin product such as a polylactic acid (PLA) resin film, and more particularly, to an eco-friendly plasticizer-containing biodegradable resin composition and a biodegradable resin product prepared therefrom. 
     BACKGROUND ART  
     Sheets using a petroleum resin such as polyvinyl chloride and the like are widely used in interior materials of buildings, materials for windows and doors thereof, and the like. In particular, films and sheets using PVC are widely used for flooring materials, wallpapers, decorative sheets, various interior sheets, and the like. 
     Since commercial resins such as PVC are prepared from petroleum, it is anticipated that such resins will become increasingly difficult to produce due to depletion of petroleum reserves and non-biodegradability of such resins will also poses an environmental problem. 
     In addition, considering increasing interest in environmental problems in recent years, PVC-based products have problems, such as safety problems in use, environmental problems, emission of endocrine disruptors upon disposal, and the like, due to dioctyl phthalate, which is a phthalate plasticizer, and various additives. 
     To resolve such problems, biodegradable resins, such as polylactic acid (PLA) resins prepared by polymerization of lactic acid extracted from plant resources, are a focus of research in recent years. 
     Further, as for a plasticizer, citrate plasticizers such as acetyl tributyl citrate (ATBC) and tributyl citrate (TBC) are applied. 
     However, the citrate plasticizers have a limit of low plasticization. 
     In the related art, Korean Patent Publication No. 10-2010-0000782A (published on Jan. 6, 2010) discloses a biodegradable polylactic acid resin composition and a technique for using a supercritical fluid instead of a phthalate plasticizer. 
     DISCLOSURE  
     Technical Problem  
     It is one aspect of the present invention to provide a biodegradable resin composition which can improve low plasticization of citrate plasticizers while containing an eco-friendly plasticizer. 
     It is another aspect of the present invention to provide a resin product, which is fabricated using from the composition as set forth above, and thus exhibits excellent plasticization and can be biodegraded after disposal. 
     Technical Solution 
     In accordance with one aspect of the present invention, a biodegradable resin composition includes a biodegradable resin and a plasticizer, wherein the plasticizer includes a benzoate plasticizer. 
     The plasticizer may include at least one selected from 2-(2-(2-phenylcarbonyloxyethoxy)ethoxy)ethyl benzoate, glyceryl tribenzoate, trimethylolpropane tribenzoate, isononyl benzoate, 1-methyl-2-(2-phenylcarbonyloxypropoxy)ethyl benzoate, 2,2,4-trimethyl-1,3-pentanediol dibenzoate, n-hexyl benzoate, and trimethylolpropane tribenzoate. 
     Here, the plasticizer may be present in an amount of 5 parts by weight to 50 parts by weight based on 100 parts by weight of the biodegradable resin. 
     In addition, the biodegradable resin composition may further include 20 parts by weight or less of an acrylic copolymer based on 100 pats by weight of the biodegradable resin. 
     Further, the biodegradable resin composition may further include 10 parts by weight or less of a higher fatty acid based on 100 pats by weight of the biodegradable resin. 
     Furthermore, the biodegradable resin composition may further include 10 parts by weight or less of an anti-hydrolysis agent based on 100 pats by weight of the biodegradable resin. 
     The biodegradable resin may include at least one selected from polylactic acid (PLA), polyglycolic acid, polycaprolactone, aliphatic polyester, polyhydroxybutyric acid, and D-3-hydroxybutyric acid resins. 
     In accordance with another aspect of the present invention, a biodegradable resin product has a single layer structure or a stacked structure of two or more layers, wherein at least one selected from the layers includes a biodegradable resin and a plasticizer. Here, the plasticizer includes a benzoate plasticizer. 
     Advantageous Effects 
     According to the present invention, the biodegradable resin composition is eco-friendly since the composition does not use phthalate plasticizers, and can improve low plasticization of citrate plasticizers. 
     Therefore, when products, such as films, flooring materials, wallpapers and the like, are fabricated using the biodegradable resin composition according to the present invention, there is a merit in that the resin composition can be more easily molded at high temperature. 
     BEST MODE  
     The above and other aspects, features and advantages of the present invention will become apparent from the detailed description of the following embodiments. 
     However, it should be understood that the present invention is not limited to the following embodiments and may be embodied in different ways, and that the embodiments are provided for complete disclosure and thorough understanding of the invention by those skilled in the art. The scope of the invention should be defined only by the accompanying claims and equivalents thereof. 
     Hereinafter, exemplary embodiments of the present invention will be described in detail. 
     According to one embodiment of the present invention, a biodegradable resin composition includes a biodegradable resin and a plasticizer. 
     Here, according to the present invention, the plasticizer is a benzoate plasticizer. As described above, although a citrate plasticizer, such as acetyl tributyl citrate (ATBC) and tributyl citrate (TBC), is mainly used as an eco-friendly plasticizer, the citrate plasticizer has a problem of low plasticization. However, from results of many studies, the inventors of the present invention found that, since the benzoate plasticizer can overcome the drawback of the citrate plasticizer while securing eco-friendliness and thus can exhibit higher plasticization than typical citrate plasticizers, moldability of the resin composition can be further improved. 
     The benzoate plasticizer may include 2-(2-(2-phenylcarbonyloxyethoxy)ethoxy)ethyl benzoate, glyceryl tribenzoate, trimethylolpropane tribenzoate, isononyl benzoate, 1-methyl-2-(2-phenylcarbonyloxypropoxy)ethyl benzoate, 2,2,4-trimethyl-1,3-pentanediol dibenzoate, n-hexyl benzoate, trimethylolpropane tribenzoate, and the like. These may be used alone or in combination thereof. 
     Therefore, when products such as films are fabricated using the biodegradable resin composition according to the present invention, there are merits in that the resin composition is easily processed into the products due to excellent plasticization, and can provide flexible products. 
     In addition, other eco-friendly plasticizers, such as citrate plasticizers and the like, may also be used together with the benzoate plasticizer. 
     Here, the plasticizer may be present in an amount of 5 parts by weight to 50 parts by weight based on 100 parts by weight of the biodegradable resin, without being limited thereto. If the amount of the plasticizer is less than 5 parts by weight, the plasticizer cannot sufficiently act as a plasticizer. On the other hand, if the amount of the plasticizer is greater than 50 parts by weight, some of the plasticizer can leak out of a product after processing of the product. 
     In addition, the biodegradable resin composition according to the present invention may further include an acrylic copolymer. The acrylic copolymer acts as a melt strength enhancer and thus contributes to securing melt strength of the composition upon product processing. 
     When the acrylic copolymer is added, the acrylic copolymer may be present in an amount of 20 parts by weight or less based on 100 parts by weight of the biodegradable resin. If the amount of the acrylic copolymer is greater than 20 parts by weight, a product can suffer from deterioration in properties such as flexibility and the like. 
     Further, the biodegradable resin composition according to the present invention may further include a higher fatty acid. The higher fatty acid acts as a lubricant and thus serves to improve lubricity and processability upon product processing. For example, the higher fatty acid may include C 18  stearic acid. 
     When the higher fatty acid is added, the higher fatty acid may be present in an amount of 10 parts by weight or less based on 100 parts by weight of the biodegradable resin. If the amount of the higher fatty acid is greater than 10 parts by weight, a prepared biodegradable resin product can suffer from deterioration in impact resistance, gloss, and the like. 
     Furthermore, the biodegradable resin composition according to the present invention may further include an anti-hydrolysis agent. The anti-hydrolysis agent suppresses hydrolysis in the composition and thus contributes to improvement of water resistance of a prepared biodegradable resin product. For example, the anti-hydrolysis agent may include carbodiimide and oxazoline. 
     When the anti-hydrolysis agent is added, the anti-hydrolysis agent may be present in an amount of 10 parts by weight or less based on 100 parts by weight of the biodegradable resin. If the amount of the anti-hydrolysis agent is greater than 10 parts by weight, a prepared biodegradable resin product can suffer from deterioration in moldability. 
     The acrylic copolymer, higher fatty acid and the anti-hydrolysis agent may be used alone or in combination thereof. 
     According to the present invention, the biodegradable resin may be any resin without limitation so long as the resin is biodegradable. The biodegradable resin may include at least one selected from polylactic acid (PLA), polyglycolic acid, polycaprolactone, aliphatic polyester, polyhydroxybutyric acid, and D-3-hydroxybutyric acid resins. Here, the biodegradable resin is preferably a PLA resin exhibiting properties similar to a commercial resin such as a polyethylene terephthalate (PET) resin. 
     As described above, the biodegradable resin composition according to the present invention is eco-friendly since the composition does not use a non-phthalate plasticizer, and can exhibit excellent moldability at high temperature while securing biodegradability by improving low plasticization of the citrate plasticizers. 
     According to the present invention, biodegradable resin products, such as films, flooring materials, wallpapers and the like, can be fabricated through a process such as melt extrusion, calendering, pressing, and the like. 
     According to the present invention, the biodegradable resin product may have a single layer structure or a stacked structure in which two or more layers are laminated. Here, at least one selected from the layers of the biodegradable resin product includes a biodegradable resin and a plasticizer, wherein the plasticizer is a benzoate plasticizer. 
     In addition, as described above, the benzoate plasticizer may include at least one selected from 2-(2-(2-phenylcarbonyloxyethoxy)ethoxy)ethyl benzoate, glyceryl tribenzoate, trimethylolpropane tribenzoate, isononyl benzoate, 1-methyl-2-(2-phenylcarbonyloxypropoxy)ethyl benzoate, 2,2,4-trimethyl-1,3-pentanediol dibenzoate, n-hexyl benzoate, and trimethylolpropane tribenzoate. 
     Further, other eco-friendly plasticizers may also be used in conjunction with the benzoate plasticizer. 
     Furthermore, the plasticizer may be present in an amount of 5 parts by weight to 50 parts by weight based on 100 parts by weight of the biodegradable resin. 
    
    
     EXAMPLE 
     Next, the present invention will be explained in more detail with reference to some examples. It should be understood that these examples are provided for illustration only and are not to be in any way construed as limiting the present invention. 
     A description of details apparent to those skilled in the art will be omitted for clarity. 
     1. Preparation of Film Using Resin Composition 
     Example 1   
     A 0.5 mm thick film was prepared by calendering at a temperature of 110° C. using a composition composed of 100 parts by weight of a PLA resin and 20 parts by weight of 2-(2-(2-phenylcarbonyloxyethoxy)ethoxy)ethyl benzoate as a plasticizer. 
     Example 2   
     A 0.5 mm thick film was prepared by calendering at a temperature of 105° C. using a composition composed of 100 parts by weight of a PLA resin, and 15 parts by weight of glyceryl tribenzoate and trimethylolpropane tribenzoate as a plasticizer. 
     Example 3   
     A film was prepared in the same manner as in Example 1 except that the composition further included 10 parts by weight of an acrylic copolymer. 
     Example 4   
     A film was prepared in the same manner as in Example 1 except that the composition further included 10 parts by weight of an acrylic copolymer, 5 parts by weight of stearic acid as a higher fatty acid, and 5 parts by weight of carbodiimide as an anti-hydrolysis agent. 
     Comparative Example 1   
     A film was prepared in the same manner as in Example 1 except that 20 parts by weight of dioctyl phthalate, which is a phthalate plasticizer, was used as the plasticizer. 
     Comparative Example 2   
     Using 100 parts by weight of a PLA resin and 20 parts by weight of acetyl tributyl citrate (ATBC), which is a citrate plasticizer, as a plasticizer, a 0.5 mm thick film was prepared by calendering at a temperature of 140° C. 
     Comparative Example 3   
     A film was prepared in the same manner as in Comparative Example 2 except that calendering was performed at a temperature of 110° C. 
     2. Property Evaluation 
     (1) Crumbling 
     For each of the films of Examples 1 to 4 and Comparative Examples 1 to 3, whether the film suffered from crumbling was observed with the naked eye. 
     The films of Examples 1 to 4 and Comparative Examples 1 to 2 did not suffer from crumbling. However, the film of Comparative Example 3 suffered from crumbling. 
     This means that, since the resin composition of Comparative Example 3 exhibited low plasticization, the resin product prepared therefrom suffered from deterioration in properties when the resin composition was not heated to a sufficiently high temperature. 
     (2) Strength 
     For each of the films of Examples 1 to 4 and Comparative Examples 1 to 2, impact strength and tensile strength were measured. Results are shown in Table 1. 
     Impact strength (unit: kg·cm/cm) was measured in accordance with ASTM D256. 
     In addition, tensile strength (unit: kgf/cm 2 ) was measured in accordance with KS M3802. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 1 
               
             
            
               
                   
                   
               
               
                   
                   
                 Comparative 
               
               
                   
                 Example 
                 Example 
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Item 
                 1 
                 2 
                 3 
                 4 
                 1 
                 2 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Impact strength (Kg · cm/cm) 
                 8.7 
                 8.4 
                 9.2 
                 9.3 
                 9.0 
                 7.8 
               
               
                 Tensile strength (kgf/cm 2 ) 
                 84.3 
                 86.2 
                 90.7 
                 94.6 
                 87.7 
                 74.1 
               
               
                   
               
            
           
         
       
     
     As shown in Table 1, the films of Examples 1 to 4 according to the present invention exhibited excellent impact strength and tensile strength, although the films of Examples 1 to 4 were processed at lower temperatures than the film of Comparative Example 2. This means that, when the benzoate plasticizer according to the present invention is used, plasticization of the PLA resin can be further improved. 
     In addition, referring to Table 1, it can be seen that the films of Examples 1 to 4 exhibited strength properties similar to those of the film of Comparative Example 1 using a commercial phthalate plasticizer. 
     That is, a product prepared using the biodegradable resin composition according to the present invention can exhibit eco-friendliness and equivalent strength to products using a phthalate plasticizer even without using the phthalate plasticizer, and can exhibit excellent strength even at a lower temperature than a product using a citrate plasticizer. 
     Although the present invention has been described with reference to some embodiments, it should be understood that the foregoing embodiments are provided for illustrative purposes only, and that various modifications, changes, alterations, and equivalent embodiments can be made by those skilled in the art without departing from the spirit and scope of the invention. 
     Therefore, the scope of the invention should be defined only by the accompanying claims.