KR20160001309A - Biogradable polyester resin composition with an excellent heat resistance and article manufactured therefrom - Google Patents

Abstract

The present invention relates to a biodegradable polyester resin composition comprising 0.5 to 10 parts by weight of a nucleating agent per 100 parts by weight of a biodegradable polyester resin. The molded article produced from the resin composition of the present invention is excellent in heat resistance and antibacterial activity, and also has high biodegradability, thereby preventing environmental pollution during disposal.

Description

TECHNICAL FIELD [0001] The present invention relates to a biodegradable polyester resin composition having excellent heat resistance and a molded article produced therefrom. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biodegradable polyester resin composition,

The present invention relates to a biodegradable polyester resin composition, and more particularly, to a biodegradable polyester resin composition having excellent heat resistance including a polylactic acid (PLA) resin and a molded article produced therefrom.

Polypropylene, and polyvinyl chloride are used in various fields such as daily necessities including home appliances, home appliances, automobile parts, building materials or food packaging due to their good processability and durability have. However, these resin products are problematic in that the good durability at the stage of being discarded later acts as a defect and degradation in the natural world is lowered.

Polylactic acid (PLA) resins are produced by fermenting corn starch to produce lactic acid, converting the lactic acid to lactide through a chemical process, and then polymerizing the biodegradable plastic to be. Because these PLA resins are biomass-based, unlike existing crude oil-based resins, it is possible to utilize recycled resources. In production, CO ₂ , which is a global warming gas, is less discharged than water. It is an environmentally friendly material such as biodegradable by microorganisms and has appropriate mechanical strength comparable to conventional crude oil based resin.

Such PLA resins have been mainly used for packaging containers, coatings, foams, films / sheets and fibers. In recent years, they have been mixed with existing resins such as ABS, polycarbonate or polypropylene to reinforce their physical properties. There are also studies to use in such as.

On the other hand, due to the convenience of plastics, many kitchen utensils have been produced from general-purpose resins made from petroleum, but as the problem of possibility of ingestion of human body has been raised, biodegradable resins such as PLA produced from biomass Is in the spotlight. However, such a PLA resin has a characteristic that it is easily deformed by heat with respect to its biodegradability, and its application is limited.

In order to overcome such low thermal stability, attempts have been made to mix the PLA with other resins such as polypropylene or polyethylene. However, there is a problem in that the products produced are poor in biodegradability and not environmentally friendly.

Thus, the inventors of the present invention have developed a PLA resin composition which is resistant to high temperatures around 100 DEG C, and which is resistant to heat and has a high heat resistance and is environmentally friendly, wherein the resin component in the composition is composed only of 100% PLA resin.

[Korean Patent No. 1130825] [Japanese Patent Laid-Open No. 2010-260899]

An object of the present invention is to provide a biodegradable polyester resin composition which is crystallized within a short period of time during the production of a molded article and which has excellent heat resistance.

The present invention also provides a molded article excellent in heat resistance produced from the biodegradable polyester resin composition.

In order to achieve the above object,

According to an aspect of the present invention,

It is possible to provide a biodegradable resin composition comprising 0.5 to 10 parts by weight of a nucleating agent per 100 parts by weight of a biodegradable polyester resin.

In one embodiment, the biodegradable polyester resin may be a polylactic acid (PLA) resin.

In one embodiment, the nucleating agent includes a sorbitol compound, a metal salt of a carboxylic acid, an aromatic phosphate ester compound, silica, talc, and the like. The nucleating agent can increase the crystallization rate of the biodegradable polyester resin and increase the heat resistance of the molded article.

In one embodiment, the biodegradable resin composition may further comprise 0.1 to 5 parts by weight of the antimicrobial agent. The antimicrobial agent serves to impart an antibacterial property to a molded article produced from the resin composition.

In one embodiment, the biodegradable resin composition may further comprise 1 to 15 parts by weight of at least one additive selected from the group consisting of stabilizers, slip agents, dispersants, coupling agents, antioxidants, and UV stabilizers.

Further, another aspect of the present invention can provide a biodegradable molded article comprising the biodegradable resin composition.

In one embodiment, the molded article may be manufactured such that the mold temperature during injection of the biodegradable resin composition is 100 to 150 ° C, and the cooling time after injection is 3 minutes or less.

According to the present invention, it is possible to provide a biodegradable polyester resin composition having excellent heat resistance and a molded article produced therefrom. In addition, the resin composition may further include an antimicrobial agent to impart an antibacterial property to the molded article. Therefore, the resin composition of the present invention is particularly advantageous for the production of kitchen utensils requiring safety, heat resistance and antibacterial properties.

1 is a photograph showing a heat resistance test process of a specimen according to an embodiment and a comparative example of the present invention,
2 is a photograph showing the degree of warpage of a specimen after heat resistance test according to an embodiment of the present invention and a comparative example,
3 is a photograph showing the test results of antibacterial activity of a test piece according to one embodiment of the present invention and a comparative example,
4A and 4B are photographs showing a thermogram obtained by using DSC to evaluate thermal characteristics of a specimen according to an embodiment of the present invention and a comparative example.

Hereinafter, the present invention will be described more specifically.

One aspect of the present invention can provide a biodegradable resin composition comprising 0.5 to 10 parts by weight, preferably 1 to 5 parts by weight of a nucleating agent per 100 parts by weight of a biodegradable polyester resin.

The biodegradable polyester resin is preferably an aliphatic polyester or an aliphatic-aromatic polyester comprising a polyhydroxycarboxylic acid, a hydroxycarboxylic acid or an aliphatic polyhydric alcohol and an aliphatic polybasic acid, or a hydroxycarboxylic acid or an aliphatic polyhydric alcohol And a monomer selected from an aliphatic polybasic acid.

Particularly, the biodegradable polyester resin may be a polylactic acid resin.

Throughout this specification, "polylactic acid resin" or "PLA resin" is defined to refer collectively to a homopolymer or copolymer comprising repeating units of the following formulas.

[General formula]

Specifically, the polylactic acid may be a homopolymer of D-lactic acid, a homopolymer of L-lactic acid, or a copolymer of L-lactic acid and D-lactic acid.

The polylactic acid resin is a natural polyester resin produced by an ester reaction using lactic acid (lactic acid) obtained by decomposing corn starch as a monomer, and is commercially available.

The polylactic acid resin preferably contains 95 parts by weight or more of L-lactic acid in terms of balance of heat resistance and moldability, and 95 to 100 parts by weight of L-lactic acid and 0 to 5 parts by weight of D- It is preferable to use a polylactic acid resin.

The polylactic acid resin has a specific gravity in the range of 1.235 to 1.239, and there is no particular limitation with respect to the molecular weight or the molecular weight distribution within a range in which molding processing is possible, but it is preferable that the polylactic acid resin has a weight average molecular weight of 80,000 or more.

The resin composition of the present invention includes a nucleating agent. The nucleating agent can increase the crystallization rate of the biodegradable polyester resin and increase the heat resistance of the molded article.

Examples of the nucleating agent of the present invention include a sorbitol compound, a metal salt of a carboxylic acid, an aromatic phosphate ester compound, silica, and talc. Of course, one or more of these compounds may be used in combination.

Examples of the aromatic phosphate ester compound include triphenyl phosphate, tri (2,6-dimethyl) phosphate bis (dimethyl phenyl) phosphate, resorcinol bis (diphenyl) phosphate, resorcinol bis (2,6- (2,4-ditertiary butylphenyl) phosphate, hydroquinolbis (2,6-dimethylphenyl) phosphate, hydroquinolbis (2,4-ditertiarybutylphenyl) phosphate and the like .

Examples of the sorbitol compound include dibenzylidene sorbitol, 1,3,2,4-di- (methylbenzylidene) sorbitol, 1,3,2,4- (ethylbenzylidene) sorbitol, 2,4- (methoxybenzylidene) sorbitol, 1,3,2,4- (ethoxybenzylidene) sorbitol, 1,2,3-trideoxy-4,6-5,7-bis- [(4-propylphenyl) methylene] nonitol, and the like.

Examples of the metal salt of the carboxylic acid include sodium adipate, potassium adipate, aluminum adipate, sodium sebacate, potassium sebacate, aluminum sebacate, sodium benzoate, aluminum benzoate, di-para-t -Butyl benzoate, titanium di-para-t-butylbenzoate, chromium di-para-t-butylbenzoate and aluminum hydroxy-di-t-butylbenzoate.

The nucleating agent showed the effect of shortening the crystallization rate of the PLA resin by about 10 times as compared with the case where the nucleating agent was not used and by about three times as compared with the case of adding the nucleating agent such as talc. Although the molded article of the present invention is made of only PLA resin of 100% according to the addition of the nucleating agent, heat resistance that can endure up to 100 deg. C at around Tg 65 deg.

The resin composition of the present invention may contain 0.5 to 10 parts by weight, preferably 1 to 5 parts by weight, of the nucleating agent per 100 parts by weight of the biodegradable polyester resin. When the amount of the nucleating agent is less than 0.5 parts by weight, the crystallization rate is not greatly affected. When the amount of the nucleating agent is more than 10 parts by weight, the impact strength of the polylactic acid resin is lowered due to high cost and excessive crystallization.

In one embodiment, the resin composition of the present invention may contain 0.1 to 5 parts by weight, preferably 0.5 to 1 part by weight, of the antimicrobial agent per 100 parts by weight of the biodegradable polyester resin. This is because the use in these ranges is preferable in terms of balance of antibacterial properties and mechanical properties.

The antimicrobial agent serves to impart an antibacterial property to a molded article produced from the resin composition, and includes an antibacterial agent, an antifungal agent, a bactericide, a sterilizing agent, or a sensitizer.

The antimicrobial agent is preferably selected from the group consisting of oxides, hydroxides, and combinations thereof including elements selected from the group consisting of transition metals, silicon, aluminum, alkali metals, alkaline earth metals, and combinations thereof, Is more preferable. The transition metal may be selected from the group consisting of zirconium, titanium, zinc, copper, and combinations thereof.

However, when the resin composition of the present invention is molded into a kitchen utensil, it is preferable to use a product that is not harmful even when ingested by a human body. One such is the ZEOMIC DLZ502 from Sinanen Zeomic.

In one embodiment, the resin composition of the present invention may further comprise at least one additive selected from the group consisting of a stabilizer, a slip agent, a dispersant, a coupling agent, an antioxidant and a UV stabilizer, It follows the well-known range.

Examples of the stabilizer include, but are not limited to, trimethyl phosphate, triphenyl phosphate, and the like.

The slipping agent may be at least one selected from the group consisting of calcium stearate, zinc stearate, PE WAX, and general WAX, but is not limited thereto.

The dispersing agent may be carboxylated polyethylene, phthalic acid, stearic acid or the like, but is not limited thereto.

The antioxidant may be one or more selected from the group consisting of Irganox series, Ultranox series and TEP series, but is not limited thereto.

The UV stabilizer may be HALS (sterically hindered amine) series, but is not limited thereto.

Further, another aspect of the present invention can provide a biodegradable molded article comprising the biodegradable polyester resin composition.

The molded article may be manufactured using various molding methods known in the art by those having ordinary skill in the art. If the injection molding method is used, for example, the biodegradable resin composition of the present invention is prepared, and the temperature of the mold at injection is 100-150 占 폚, preferably 110-130 占 폚, and the cooling time after injection is 3 minutes .

The molded article produced by molding the biodegradable polyester resin composition having excellent heat resistance of the present invention is useful as a molded article in fields requiring safety, heat resistance and antibacterial property, such as a kitchen article, a sundry article, an automobile, a machine component, And the like.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited thereto.

Example 1:

Polylactic acid (Ingeo ^TM biopolymer, Natureworks US), 100 parts by weight of a nucleating agent CR741S (bis (dimethylphenyl) phosphate bisphenol A, And 1 part by weight of an antimicrobial agent (Sinanen Zeomic, ZEOMIC DLZ502) were mixed and made into a pellet state using a twin screw extruder.

Example 2:

Polylactic acid (Ingeo ^TM biopolymer, Natureworks US) and 1 part by weight of nucleating agent CR741S (bis (dimethylphenyl) phosphate bisphenol A, Japan Daefal Chemical Co., Ltd.) were mixed and prepared in a pellet state using a twin screw extruder.

Example 3:

Nucleating agent CR741S (bis (dimethylphenyl) phosphate bisphenol A, Japan Daefal Chemical) 3 parts by weight The pellets were prepared in the same manner as in Example 1, except that they were mixed.

Comparative Example 1:

Polylactic acid (Ingeo ^TM biopolymer, Natureworks US) and 1 part by weight of an antimicrobial preparation (Sinanen Zeomic, ZEOMIC DLZ502) were mixed and prepared in a pellet state using a twin screw extruder.

Comparative Example 2:

Polylactic acid (Ingeo ^TM biopolymer, Natureworks US) resin was prepared in a pellet state using a twin-screw extruder.

Test Example 1: Heat resistance test

In the above Examples or Comparative Examples, pelletization of each component was carried out by heating, melting, and mixing in an extruder, and injection and test specimens were prepared and evaluated for their properties.

The specimen was 365mm X 200mm X 4T in size and the ratio of thickness to height was 1.83: 1.

For the heat resistance test, two round specimens were placed at intervals of 4 cm according to KS G 5602 7.5: 2006, and a sample was placed thereon. Then, a weight of 500 g was placed thereon and left for 1 hour at 85 ° C. The specimens were left to stand for 10 minutes at room temperature with the weight removed, and the bending heights were compared.

Generally, PLA is hydrolyzed in hot water or strong acid and is known to weaken above its Tg of 65 ° C.

As can be seen visually, the specimen of Example 1 was observed to have no warpage or weakly, but the specimen of Comparative Example 1 had a relatively large warp height (see Table 1, Figs. 1 and 2).

Test Items Test result Example 1 Comparative Example 1 80 ° C Maximum bending height (mm) 0.0 0.5 90 ° C Maximum bending height (mm) 0.2 2.2 100 ° C Maximum bending height (mm) 0.5 2.5

Test Example 2: Biodegradability test

The biodegradability test of the specimens was carried out according to the method of KS M ISO 14855-1: 2010.

A cellulose sample was used as a standard sample. The results are shown in the table below.

matter The average biodegradability calculated by carbon dioxide emission Test period (days) observe Example 1 72.42 45 No specificity such as water content, color, odor etc.
Standard sample 75.73 45
Biodegradation (%) of specimen to standard sample 95.63

As can be seen from Table 2, the specimen of Example 1 shows similar biodegradability to cellulose, which is known to have excellent biodegradability.

Test Example 3: Antibacterial test

The antimicrobial activity and efficacy of the prepared specimens were performed according to the film-contacting method (ISO 22196, JIS Z 2801: 2010). The strains were Staphylococcus aureus (ATCC 6538P) and Escherichia coli (ATCC 8739) Respectively.

The film-contacting method is the most suitable method for analyzing the antibacterial activity of a plastic product to which an inorganic antibacterial agent is applied, in which the migration of metal particles is limited to the plastic surface. The microorganism is inoculated on the surface of the sample, This is a method of measuring viable cell count. The numerical value when the antibacterial activity is effective by this method is 99% or more (log value = active value 2).

As a result, both of the two strains actively proliferated in the specimen of Comparative Example 2 in which the antimicrobial agent was not added. In the specimen of Example 1, 99.9% of the strains were killed against both strains (see FIG. 3).

Test Example 4: Evaluation of thermal characteristics

DSC (Differential Scanning Calorimeter) analysis was performed on the specimen of Example 1 and the specimen of Comparative Example 1. [ The apparatus was Pyris Diamond (PerkinElmer), and was performed under conditions of 10 to 190 ° C, 10 ° C / min, and nitrogen gas of 20 psi.

As a result, as can be seen from the thermograms of FIGS. 4A and 4B, the specimen of Comparative Example 1 in which no nucleating agent was added had no crystallization region and a large number of amorphous regions, and crystallization could be measured by heating in DSC analysis.

However, the specimen of Example 1 in which the degree of crystallization was increased by the addition of the nucleating agent, showed no crystallization point by heating in the DSC analysis. This is because crystallization has already occurred before that.

From the above results, it has been confirmed that polylactic acid and a nucleating agent are mixed to increase the degree of crystallization in an injection process, thereby producing a molded article having excellent heat resistance. Further, it can be seen that antimicrobial properties can be imparted to the resin by adding an antimicrobial agent.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. As will be understood by those skilled in the art. It is therefore to be understood that the embodiments described above are in all respects illustrative and not restrictive.

Claims (10)

A biodegradable polyester resin composition comprising 0.5 to 10 parts by weight of a nucleating agent based on 100 parts by weight of a biodegradable polyester resin. The biodegradable polyester resin composition according to claim 1, wherein the biodegradable polyester resin is a polylactide (PLA) resin. The biodegradable polyester resin composition according to claim 1, wherein the nucleating agent is at least one selected from the group consisting of a sorbitol compound, a metal salt of a carboxylic acid, an aromatic phosphate ester compound, silica, and talc. The biodegradable polyester resin composition according to claim 3, wherein the nucleating agent is an aromatic phosphate ester compound. 5. The method according to claim 4, wherein the aromatic phosphoric acid ester compound is selected from the group consisting of triphenyl phosphate, tri (2,6-dimethyl) phosphate, bis (dimethyl phenyl) phosphate, resorcinol bis (diphenyl) phosphate, resorcinol bis (2,4-ditertiarybutylphenyl) phosphate, hydroquinolbis (2,6-dimethylphenyl) phosphate and hydroquinolbis (2,4-ditertiarybutylphenyl) Wherein the biodegradable polyester resin composition is a biodegradable polyester resin composition. The biodegradable polyester resin composition according to claim 1, further comprising 0.1 to 5 parts by weight of an antimicrobial agent. The antimicrobial agent according to claim 1, wherein the antimicrobial agent is selected from the group consisting of oxides, hydroxides, and combinations thereof including elements selected from the group consisting of transition metals, silicon, aluminum, alkali metals, alkaline earth metals, Wherein the biodegradable polyester resin composition is a biodegradable polyester resin composition. The biodegradable polyester resin composition according to claim 1, further comprising at least one additive selected from the group consisting of a stabilizer, a slip agent, a dispersant, a coupling agent, an antioxidant, and a UV stabilizer. 9. A molded article produced from the biodegradable polyester resin composition according to any one of claims 1 to 8. The molded article according to claim 9, wherein the molded article is a kitchen article.

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