KR101485386B1 - Manufacturing method of aliphatic polyester crystallization products and products manufactured by the method - Google Patents

Abstract

The present invention relates to a method for manufacturing an aliphatic polyester resin molded product and an aliphatic polyester molded product manufactured by the same. The method for manufacturing an aliphatic polyester resin molded product according to the present invention comprises: a molding step of preparing a molded material using a composition containing an aliphatic polyester resin; and a crystallizing step of immersing and crystallizing the molded material, which is prepared in the molding step, in hot water at a temperature of 50-130°C for 5-600 seconds. The method for manufacturing an aliphatic polyester resin molded product according to the present invention comprises a step of immersing and crystallizing the molded material, which is prepared using an aliphatic polyester resin, in hot water under predetermined conditions, and thus the manufactured molded product has improved heat resistance while maintaining biodegradability, environmental performance, and hardness, which are characteristics of the aliphatic polyester resin, thereby sufficiently ensuring dimensional stability.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for producing an aliphatic polyester resin molded article and an aliphatic polyester resin molded article produced by the method. [0002]

The present invention relates to a method for producing an aliphatic polyester resin molded article and an aliphatic polyester resin molded article produced by the method. More particularly, the present invention relates to a process for producing a molded article by using an aliphatic polyester resin capable of biodegradation, wherein the basic properties such as biodegradability, environmental friendliness and strength are maintained by controlling the crystallization step in the process of producing a molded article, and heat resistance, productivity, durability, And the like, and an aliphatic polyester resin molded article produced by the method.

Polymer materials derived from plants are attracting attention because of environmental pollution problems caused by discarded polymers and soaring petroleum prices. Recently, biodegradable polymers, which can be decomposed by microorganisms in the soil or the sea, are in the spotlight as environmental pollution becomes serious. Among these polymers, aliphatic polyester resins are most studied as plant-derived biodegradable polymers because of their excellent processability and easy control of their decomposition characteristics. Among them, polylactic acid (PLA) currently forms a market of about 150,000 tons, and the scope of application is expanding to areas requiring durability such as disposable products, food packaging materials and electronic product cases.

However, since polylactic acid among aliphatic polyesters is generally low in heat resistance, there arises a problem that the molded product is deformed when the external temperature rises above 60 deg. Due to these problems, the non-crystallized pulley lactic acid resin is insufficient in heat resistance and its application range is greatly reduced. Therefore, in order to expand the application range of the aliphatic polyester resin and the market area, it is necessary to improve the heat resistance of the product.

A variety of techniques have been developed to improve the heat resistance of molded articles produced using aliphatic polyester resins.

Japanese Patent Application Laid-Open Nos. 2005-220177, 2005-200517, and 2005-336220 disclose a technique of mixing glass fibers so as to simultaneously improve heat resistance and mechanical strength. However, it is not preferable to add harmful glass fiber to the environmentally friendly resin, which is disadvantageous in that the glass fiber does not become biodegradable after disposal and a problem occurs in the operation.

Korean Patent Publication No. 2005-0056021 discloses a technique for improving impact resistance and heat resistance by mixing polylactic acid and polycarbonate resin. However, as the content of the polycarbonate resin increases, the specific gravity of the petroleum-based plastic resin increases, and the content of the bisphenol-A, which is a harmful substance with the increase of the content of the polycarbonate resin, is accompanied. There is a problem that the polylactic acid resin results in a contradictory purpose.

Japanese Patent Laid-Open Publication No. 2011-089084 discloses a technique for obtaining a molded body obtained by molding a polylactic acid resin composition comprising a polylactic acid resin and a polyglycerin fatty acid ester at 100 to 280 캜 and then cooling the same to promote crystallization . Korean Patent Laid-Open Publication No. 2014-0011025 discloses that a poly (lactic acid) resin composition is fed into a cavity having a surface temperature of 90 to 120 占 폚 and then held and crystallized for 10 to 100 seconds. Then, the cavity surface is cooled to 40 to 60 占 폚, And then the molded product is heat-treated at 90 to 120 DEG C for 10 to 60 minutes. These techniques crystallize in the molding step and perform additional heat treatment as required. However, these techniques still have insufficient heat resistance and dimensional stability.

It is therefore an object of the present invention to provide a method for manufacturing a molded article using plant-derived biodegradable aliphatic polyester resin by controlling the crystallization step in order to secure excellent heat resistance and dimensional stability while maintaining biodegradability, environment friendliness and rigidity, And a method for producing an aliphatic polyester resin molded article capable of improving the productivity.

Another object of the present invention is to provide an aliphatic polyester resin molded article in which dimensional stability and heat resistance are improved by controlling the crystallization step.

According to an aspect of the present invention, there is provided a method of manufacturing a molded article, the method including: forming a molded article using a composition comprising an aliphatic polyester resin; And a crystallization step of crystallizing the molded product produced in the molding step by immersing the molded product in hot water at 50 to 130 ° C for 5 to 600 seconds to crystallize the molded product of aliphatic polyester resin.

And a post-treatment step of treating the molded article crystallized in the crystallization step with hot air at 50 to 130 ° C.

The aliphatic polyester resin may be a poly lactic acid resin.

The aliphatic polyester resin may be a poly (lactic acid) resin, and the composition may comprise 0.1 to 20 parts by weight of a nucleating agent and 1 to 100 parts by weight of other biodegradable resin per 100 parts by weight of the poly (lactic acid) resin.

The other biodegradable resin is selected from the group consisting of polybutylene succinate PBS, polycaprolactone PCL, polybutylene adipate terephthalate (PBAT), polyhydroxyalkanoate PHA), polyhydroxybutyrate (PHB), and the like.

In order to attain the above object, the present invention provides an aliphatic polyester resin molded article, which is produced by the above-mentioned production method.

The above-described method for producing an aliphatic polyester resin molded article according to the present invention is characterized in that a molded article produced by using an aliphatic polyester resin is immersed in a hot water under a predetermined condition to crystallize, thereby maintaining biodegradability, environment friendliness and rigidity Improvement in heat resistance and excellent dimensional stability can be ensured.

Particularly, the aliphatic polyester resin molded article produced according to the present invention exhibits excellent dimensional stability and heat resistance, while being an eco-friendly product having biodegradability. Therefore, the effect of expanding the application area and the market area of the aliphatic polyester product can be obtained.

In addition, since the crystallization time is shortened, the productivity of aliphatic polyester products can be increased, so that it is possible to produce heat-resistant products with price competitiveness, and it is possible to produce heat-resistant products with complicated structure by improving dimensional stability, The effect can be obtained.

Fig. 1 is a block diagram showing an example of a constant-temperature heating water heater.
Fig. 2 is a view showing a specimen structure used in Examples and Comparative Examples. Fig.

Hereinafter, the present invention will be described in detail.

The term " molded article " in the present invention refers to a product finally produced through the manufacturing method according to the present invention. The term " molded article "

The method for producing an aliphatic polyester resin molded article according to the present invention includes: a molding step of producing a molded article using a composition comprising an aliphatic polyester resin; And a crystallization step of crystallizing the shaped body produced in the imaginary body forming step by immersing the shaped body in hot water at 50 to 130 ° C for 5 to 600 seconds.

The molding step is to produce a molded article using a composition comprising an aliphatic polyester resin, and the composition can be used without any limitations that are commonly used in the art.

Preferably, the aliphatic polyester resin may be a poly lactic acid resin. In this case, the composition may be a polylactic acid resin itself. However, in order to produce a molded product of higher quality, the aliphatic polyester resin is a poly (lactic acid) resin, and the composition includes 0.1 to 20 parts by weight of a nucleating agent and 1 to 100 parts by weight of other biodegradable resin per 100 parts by weight of the poly Is preferably used.

Generally, polylactic acid resins can be classified into crystalline PLA (c-PLA) resins and amorphous PLA (a-PLA) resins. When the amorphous PLA resin alone is used, the object of the present invention can not be achieved. Therefore, the polylactic acid resin preferably includes a crystalline PLA resin. If the poly (lactic acid) resin contains a crystalline PLA resin, a sufficient processing efficiency may be increased without addition of a nucleating agent.

When a crystalline PLA resin is included in the polylactic acid resin, it is most preferable to use only a crystalline PLA resin as the polylactic acid resin. If necessary, a crystalline PLA resin and an amorphous PLA resin may be mixed and used. Preferably, the polylactic acid resin is obtained by polymerizing L-lactic acid, D-lactic acid or a racemic mixture thereof. The molecular weight of the poly (lactic acid) resin is preferably 10,000 or more, and more preferably 10,000 to 1,000,000.

The nucleating agent is used for improving the crystallization rate during the molding of the poly (lactic acid) resin, and any one generally used in the art can be used without limitation.

For example, the nucleating agent may be added with an organic compound having a melting point or softening point of 80 to 300 DEG C and a melting entropy of 10 to 100 cal / K / mol.

For example, the nucleating agent may be an inorganic particle, a sorbitol derivative, an amide compound and a phosphorus compound metal salt. These may be used alone or in combination of two or more.

Examples of the inorganic particle nucleating agent include clay such as calcium silicate filler (wollastonite), mica, talc (granular talc using powdery talc or rosin as a binder), kaolin, potassium titanate whisker, boron nitride, layered silicate, , Carbon fiber, and the like. It is preferable that the inorganic particles have a particle diameter of 0.01 to 5 탆 in consideration of the dispersion state in the composition. More preferably, the inorganic particles have a particle size of 0.01 to 3.0 탆, more preferably a particle size of 1.5 to 3.0 탆, and still more preferably a powdery talc having a particle size of 1.5 to 2.0 탆.

Examples of the sorbitol derivative nucleus agent include bis (p-methylbenzylidene) sorbitol, bis (p-ethylbenzylidene) sorbitol, bis (n-propylbenzylidene) sorbitol, bis (p-isopropylbenzylidene) sorbitol, bis Bis (2,4-dimethylbenzylidene) sorbitol, bis (2,4,5-trimethylbenzylidene) sorbitol, bis (2,4-dimethylbenzylidene) sorbitol, bis 4,6-trimethylbenzylidene) sorbitol, bis (4-biphenylbenzylidene) sorbitol, and the like.

The amide compound nucleating agent may be an organic compound comprising an aliphatic carboxylic acid amide having an amide bond, for example, an organic compound such as capric acid amide, stearic acid amide, oleic acid amide, erucic acid amide, Aliphatic carboxylic aminomethanes having 8 to 30 carbon atoms, aromatic amines such as methylene bisstearic acid amide, ethylene bislauric acid amide, ethylene biscaproic acid amide, ethylene bisoleic acid amide, ethylene bisstearic acid amide, But are not limited to, ethylenbishebene amide, ethylene bisisostearic amide, ethylene bis hydroxystearic amide, butylene bisstearic acid amide, hexamethylene bisolenic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisbehenamide, methyl Aliphatic carboxylic acid bisamide such as benzoic acid hydroxystearic acid amide and the like can be used.

As the phosphorus compound metal salt nucleus, a phenylphosphoric acid metal salt can be used, wherein the metal salt is a lithium salt, a sodium salt, a potassium salt, a magnesium salt, a calcium salt, a barium salt, an iron salt, a cobalt salt, have. More specifically, the present invention relates to a lithium salt of phenylphosphonic acid, a sodium salt of phenylphosphonic acid, a salt of potassium phenylphosphonate, a salt of magnesiumphosphoric acid, a salt of calciumphosphonate, a salt of bismethoxyphosphonic acid, a salt of ironphosphonate, , A copper phosphate salt of phenylphosphonium, a manganese phosphate of phenylphosphonium, or a zinc phosphate salt of phenylphosphonic acid.

The nucleating agent may be contained in an amount of 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the polylactic acid resin. When the content of the nucleating agent is less than 0.1 part by weight with respect to 100 parts by weight of the poly (lactic acid) resin, the performance of the nucleating agent can not be sufficiently exhibited and the crystallization rate is lowered to deteriorate productivity. When the content of the nucleating agent is more than 20 parts by weight, There is a problem in that the physical properties of the product can be weakened.

Other biodegradable resins contained in the composition are added to compensate for the disadvantages of the polylactic acid resin. The other biodegradable resin is selected from the group consisting of polybutylene succinate PBS, polycaprolactone PCL, polybutylene adipate terephthalate (PBAT), polyhydroxyalkanoate PHA), polyhydroxybutyrate (PHB), and the like.

The other biodegradable resin may be contained in an amount of 1 to 100 parts by weight based on 100 parts by weight of the polylactic acid resin. When the content of the other biodegradable resin is less than 1 part by weight with respect to 100 parts by weight of the poly (lactic acid) resin, sufficient effect can not be obtained. When the amount of the biodegradable resin is more than 100 parts by weight, And the like.

The composition may further include additives generally added in the art as needed for the purpose of adjusting various physical properties of the molded article. The additive may include at least one selected from the group consisting of a plasticizer, a heat stabilizer, a light stabilizer, a light absorbent, a lubricant, a plasticizer, an inorganic filler, a colorant, a pigment, an antioxidant, a flame retardant, and a filler.

According to the present invention, the above-mentioned composition is used to produce a molded article. At this time, the shape of the molded product and the molding method thereof can be practiced by applying a technique commonly used in the art. For example, the molded article can be produced by designing a suitable molding method and molding conditions in consideration of the use of the molded article to be produced, and designing the molded article having the desired physical properties and structure. For example, the molded article may be formed by using a general-purpose plastic processing apparatus such as an extruder, an extruder, a sheet machine, a vacuum molding machine (including a pressure and a vacuum) 3D printer, and the like. In the present invention, the form and the molding process of the molded article are not limited.

According to the present invention, when the production of the molding is completed in the molding step, the molding is subjected to a crystallization step of immersing the molding in a hot water for crystallization. In this case, the crystallization step is performed by immersing the molded product in a hot water of 50 to 130 ° C for 5 to 600 seconds to crystallize it.

The crystallization step may be carried out by using a constant-temperature heating-stove. The constant temperature hot water heater may utilize a mechanism capable of keeping the temperature of the hot water constant, for example, a well-known constant temperature bath. For example, as shown in FIG. 1, the constant temperature hot water tank may include a water tank 101 in which a hot water (hot water) 103 is placed, and a basket 102 for containing a molding for crystallization. In the water tub 101, a heating coil 104 for keeping the temperature of the hot water 103 at a constant level is built in. When the crystallization step is carried out using the constant temperature hot water boiler having such a structure, the operator holds the formed product in the molding step in the basket 102 while keeping the temperature of the hot water at 50 to 130 ° C, ~ 600 seconds after immersion.

The temperature of the hot water is preferably 50 to 130 ° C, preferably 60 to 110 ° C, more preferably 80 to 100 ° C. The crystallization time is preferably 5 to 600 seconds, more preferably 10 to 300 seconds, and still more preferably 20 to 120 seconds.

If the hot water temperature is less than 50 ° C, the crystallization of the product may occur very late, and if the hot water temperature is more than 130 ° C, the crystallization rate may be slowed and the productivity may be deteriorated or the shape may be changed due to rapid heating of the product, . If the crystallization time is less than 5 seconds, the crystallinity of the product may be lowered and the heat resistance characteristics may be weakened. If the crystallization time is more than 600 seconds, the productivity of the product is deteriorated.

If necessary, the preliminary crystallization step may be further performed by heat treatment at 50 to 80 DEG C for 5 to 30 seconds before the crystallization step. This preliminary crystallization step can increase the degree of crystallization in the crystallization step and improve the heat resistance.

The pre-crystallization step may be performed in a process until the molded product molded in the molding step described above is immersed in hot water immediately after demoulding. For example, the pre-crystallization step may be to maintain the external temperature at the time of demolding at 50 to 80 DEG C and then leave the demolded mold for 5 to 30 seconds. Or to maintain the external temperature at 50 to 80 DEG C for 5 to 30 seconds before the molded product is immersed in the hot water for the crystallization step.

The preformed molding is immersed in hot water as described above to perform a full crystallization step. When the crystallization step is performed after the pre-crystallization step, the degree of crystallization can be increased and sufficient heat resistance can be ensured.

If necessary, the molded product crystallized in the crystallization step may be further subjected to a post-treatment step of treating with hot air at 50 to 130 ° C. The post-treatment step may be performed to remove moisture that may be contained in the crystallized molded product, and to compensate for the degree of crystallization of the uncrystallized portion that may be present in the crystallization step.

The post-treatment step may be carried out using hot air at 50 to 130 ° C, preferably 60 to 110 ° C, and most preferably 80 to 100 ° C. If the temperature of the hot air is less than 50 ° C, there is a problem that the water contained in the formed product may not sufficiently be removed or the crystallization may not be complemented. If the temperature of the hot air is higher than 130 ° C, There is a problem that the manufacturing cost may be increased due to the use of hot hot air.

When a plant-derived biodegradable aliphatic polyester resin, preferably a polylactic acid resin, is used as the aliphatic polyester resin, a molded article is subjected to a crystallization step under the above-mentioned conditions, the biodegradability, eco-friendliness and rigidity As a result, heat resistance is greatly improved, sufficient dimensional stability can be ensured, and productivity can be improved.

Hereinafter, the present invention will be described by way of preferred embodiments which are easily understood and practiced by those skilled in the art. The following examples serve to illustrate the present invention in more detail, and the scope of the present invention is not limited to these examples.

≪ Examples 1 to 16 and Comparative Examples 1 to 16 >

Polybutylenesuccinate PBS was used as the nucleating agent in the ratio shown in the following Table 1 as a non-substituted phenylphosphonic acid zinc salt (Nissan Chemical product: Ecopromot) as a nucleating agent and other biodegradable resin, .

A specimen of the type shown in FIG. 2 was prepared using the prepared composition. At this time, the injection barrel temperature was 170 캜, and the mold temperature was 30 캜 by circulating cooling water.

The prepared specimens were treated under the crystallization conditions shown in Table 1 below to prepare molded products as final products. In the case of Example 16, after the crystallization treatment, the molded product was further processed by hot air at 95 ° C for 240 seconds to prepare a final product. In Comparative Example 16, the prepared specimen was treated with hot air at 95 ° C for 240 seconds, .

< Experimental Example > Property evaluation method

The dimensional stability and heat resistance of the specimens and the molded articles prepared in the Examples and Comparative Examples were evaluated in the following manner. The results are shown in Table 1 below.

(1) Evaluation of dimensional stability

The dimensional stability was evaluated by first measuring the length (a) between both upper wall surfaces of the produced specimen of the type shown in Fig. 2, and then measuring the length a 'between both wall surfaces of the finally produced molded article after the crystallization treatment The strain was measured by the following equation (1).

[Equation 1]

(2) Evaluation of heat resistance

2 is immersed in boiling water, held for 10 seconds, taken out, and deformed by pressing for 3 seconds at a pressure of 5 kgf / cm ² from the outside of both wall surfaces of the molded article.

After the deformation, the pressure was removed from the outside and whether it was restored before applying the pressure was visually observed to determine whether or not the heat resistance was improved.

○: Restoration

×: Not restored

division Composition (parts by weight) crystallization Strain rate
(%) Heat resistance PLA Nucleating agent PBS Time (S) Hot water temperature
(° C) Example 1 100 300 50 0.7 0 Example 2 100 300 95 0.8 0 Example 3 100 300 130 0.9 0 Example 4 100 One 300 50 0.3 0 Example 5 100 One 300 95 0.3 0 Example 6 100 One 300 130 0.4 0 Example 7 100 One 20 300 50 0.5 0 Example 8 100 One 20 300 95 0.6 0 Example 9 100 One 20 300 130 0.7 0 Example 10 100 5 95 0.7 0 Example 11 100 600 95 1.0 0 Example 12 100 One 5 95 0.3 0 Example 13 100 One 600 95 0.4 0 Example 14 100 One 20 5 95 0.5 0 Example 15 100 One 20 600 95 0.6 0 Example 16 ^* 100 One 20 300 95 0.6 0 Comparative Example 1 100 300 45 0.6 X Comparative Example 2 100 300 135 1.1 0 Comparative Example 3 100 One 300 45 0.2 X Comparative Example 4 100 One 300 135 0.5 0 Comparative Example 5 100 One 20 300 45 0.4 X Comparative Example 6 100 One 20 300 135 0.8 0 Comparative Example 7 100 4 95 0.5 X Comparative Example 8 100 605 95 1.2 0 Comparative Example 9 100 One 4 95 0.2 X Comparative Example 10 100 One 605 95 0.5 0 Comparative Example 11 100 One 20 4 95 0.4 X Comparative Example 12 100 One 20 605 95 0.6 0 Comparative Example 13 100 - - 0.0 X Comparative Example 14 100 One - - 0.0 X Comparative Example 15 100 One 20 - - 0.0 X Comparative Example 16 ^* 100 One 20 - - 8.3 0

In Table 1, * indicates the addition of a process of treating with hot air at 95 DEG C for 240 seconds.

As shown in Table 1, it can be seen that the heat resistance and dimensional stability of the product manufactured using the aliphatic polyester resin during the crystallization treatment under predetermined conditions (hot water temperature and crystallization treatment time) were improved by using hot water.

On the other hand, in the case of Comparative Examples 13 to 15 in which the hot-water crystallization treatment was not carried out, the crystallization step was not performed and the dimensional change was not observed, but it was confirmed that the heat resistance was poor. Particularly, in the case of Comparative Example 16 in which the hot-air crystallization treatment is performed as in the conventional technique, the heat stability is very poor compared with the embodiments.

For reference, as in Comparative Examples 1, 3, and 5, when the temperature of the hot water is less than 50 캜, there is no improvement in heat resistance, and when the temperature of the hot water is set to more than 130 캜 as in Comparative Examples 2, 4, One is the waste of unnecessary calories and the production efficiency drops. Particularly, in the case of Comparative Examples 2, 4 and 6, even in the case of the same compositions in Examples 1 to 9, the dimensional stability is poor even when compared with those of Comparative Examples 2 and 4, 4, etc.) can be known.

However, as in Comparative Examples 7, 9, and 11, when the crystallization treatment time is less than 50, the heat resistance is not improved. When the crystallization treatment time is longer than 600 seconds as in Comparative Examples 8, 10, and 11, the heat resistance can be improved. Extension of production time results in reduced production efficiency.

It can be seen that, in Examples 4 to 9 in which a nucleating agent is added and in Examples 12 to 15, more excellent dimensional stability can be obtained as compared with Examples 1 to 3, Example 10, and Example 11 containing no nucleating agent .

As can be seen from the above, it can be seen that the heat resistance can be improved when the product produced by using the aliphatic polyester resin is subjected to crystallization treatment in a suitable time using hot water.

Therefore, based on the results of the present invention, the productivity and the functionality of the aliphatic polyester resin product can be improved by adjusting the type and amount of the nucleating agent, the crystallization temperature, and the time, according to the characteristics of the product.

The process for producing a high-performance aliphatic polyester resin molded article of the present invention can be used in the production of an environment-friendly biodegradable resin product having a complicated structure requiring heat resistance and dimensional stability within the scope of the technical idea of the present invention will be.

Claims (6)

Wherein the nucleating agent is selected from the group consisting of a lithium salt of phenylphosphonic acid, a sodium salt of phenylphosphonic acid, a potassium salt of phenylphosphonic acid, A salt selected from the group consisting of magnesium phosphates, calcium phosphates, magnesium phosphates, calcium phosphates, barium phosphates, biphenyl phosphonates, iron phosphates, cobalt phosphates, cobalt phosphates, manganese phosphates, A phosphorus compound metal salt; And
And a crystallization step of crystallizing the molded article formed in the molding step by immersing the molded article in hot water at 50 to 130 ° C for 5 to 600 seconds to crystallize the molded article. The method according to claim 1,
And a post-treatment step of treating the molded article crystallized in the crystallization step with hot air at 50 to 130 ° C. The method according to claim 1,
Wherein the aliphatic polyester resin is a polylactic acid resin. The method according to claim 1,
The aliphatic polyester resin is a polylactic acid resin,
Wherein the composition further comprises 1 to 100 parts by weight of a biodegradable resin per 100 parts by weight of the polylactic acid resin. The method of claim 4,
The biodegradable resin may be selected from the group consisting of polybutylene succinate PBS, polycaprolactone PCL, polybutylene adipate terephthalate (PBAT), polyhydroxyalkanoate PHA ), And polyhydroxybutyrate (PHB). The method for producing an aliphatic polyester resin molded article according to claim 1, The aliphatic polyester resin molded article according to any one of claims 1 to 5, which is produced by the manufacturing method according to any one of claims 1 to 5.

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