KR101989045B1 - Biodegradable resin composition having excellent weather resistance and storage stability and the method of manufacturing the same - Google Patents

Abstract

The present invention relates to a biodegradable resin composition having excellent weather resistance and storage stability and a method for manufacturing the same. More particularly, the present invention relates to: a high polymerization degree biodegradable resin composition of a low-acid value manufactured by putting an acid component comprising an aliphatic dicarboxylic acid single component or an aliphatic dicarboxylic acid and an aromatic dicarboxylic acid mixed component, and putting aliphatic diol followed by esterification reaction, condensation polymerization reaction, chain extension reaction and solid phase polymerization, wherein the high polymerization degree biodegradable resin composition of the low-acid value is, in an esterification reaction process, obtained by forming a branching agent having a ring structure and adding the same to reaction, and conducting condensation polymerization reaction to manufacture a primary resin composition, followed by putting a chain extension agent and conducting chain extension reaction and solid phase polymerization; and the method for manufacturing the same.

Description

FIELD OF THE INVENTION The present invention relates to a biodegradable resin composition having excellent weatherability and storage stability,

The present invention relates to a biodegradable resin composition having excellent weatherability and storage stability and a method of producing the same. More specifically, the present invention relates to a biodegradable resin composition having excellent weatherability and storage stability, And an aliphatic diol, and then subjected to an esterification reaction, a condensation polymerization reaction, a chain extension reaction and a solid phase polymerization. In the esterification reaction, a branching agent having a cyclic structure is formed and added to the reaction. To a high polymerization degree biodegradable resin composition having a low acid value obtained by subjecting a chain extender to a chain extension reaction and solid phase polymerization after preparing a primary resin composition, and a process for producing the same.

The biodegradable resin composition thus prepared has a melting point of 90 to 130 占 폚, a number average molecular weight of 50,000 to 100,000, a weight average molecular weight of 100,000 to 300,000, and an acid value of 0.1 mgKOH / g to 2 mgKOH / g.

Plastics are produced as household goods, medical supplies and industrial goods by various processing methods and have been used as important materials in modern life because of their light weight, durability, chemical resistance and mechanical properties.

However, most of these plastics are used once and discarded. As a result, environmental pollution caused by this has reached a level of concern in many parts of the world. One solution to this problem is to dispose of disposable products in a natural environment by microorganisms and finally water and carbon dioxide Application and development of degradable biodegradable resins have been actively conducted since the late 1990s.

The biodegradable resins developed so far are polylactic acid (PLA) obtained by extracting lactic acid or lactide from a sugar chain synthesized through photosynthesis by a plant, a polycaprolactone (PLA) synthesized through ring opening reaction with εcaprolactone as a monomer, And aliphatic or aliphatic / aromatic copolyesters obtained by esterification and polycondensation of diol-dicarboxylic acids, and polyhydroxybutyrate (PHB) produced by in-vivo synthesis of other microorganisms.

Since many research and development efforts have been made recently, the processability and mechanical properties of biodegradable resins have been greatly improved, and the gap with general non-degradable resins has been reduced, and the production cost has also been reduced.

In particular, aliphatic or aliphatic / aromatic copolyesters obtained through esterification and polycondensation of diol-dicarboxylic acids and polylactic acid, a naturally occurring polymer, are leading the market. Among these resin compositions, aliphatic or aliphatic / aromatic copolyesters are excellent in flexibility, elongation and extrusion performance, and are rapidly biodegradable. They are widely used for products such as shopping bags, garbage bags, mulching films, monofilaments and the like which require flexibility and high strength have.

However, aliphatic polyesters or aliphatic / aromatic copolyesters exhibit low tearing strength due to the orientation of the polymer chains in the direction of pulling due to the slow cooling rate during processing, and one of the advantages thereof is the rapid biodegradability, Users are dissatisfied with the problem of causing a change in the physical properties of the product over time and causing the consumer to lose the function before using the product.

Many researchers have been attempting to obtain a high molecular weight resin composition as a main method to solve this problem. A method of synthesizing a high molecular weight aliphatic polyester resin having a number average molecular weight of 30,000 or more by appropriately adjusting the reaction temperature, the degree of vacuum and the catalyst condition is disclosed in Korean Patent Application No. 93-0020638. However, the aliphatic polyester resin produced by this method has a low weight average molecular weight and is extremely sensitive to heat, resulting in poor moldability.

Korean Patent Application No. 10-1997-2703252 discloses a method of using a sulfonate compound or a compound having at least three ester-forming functional groups to prepare an aliphatic / aromatic copolyester resin. However, this method can shorten the reaction time and increase the average molecular weight, but widen the molecular weight distribution of the resulting aliphatic / aromatic copolyester composition, resulting in a large amount of copolyesters of low molecular weight. This easily causes pyrolysis during processing and is susceptible to moisture in the atmosphere, resulting in poor storage stability of the manufactured product.

There are aliphatic / aromatic copolyesters prepared by adding aromatic monomers in order to solve the problems of the above-mentioned aliphatic polyesters. As the producible methods therefor, US Pat. No. 4,328,059, US Pat. No. 4,094,721 Korean Patent Registration Nos. 10-1255826 and 10-1068030 And so on. However, to date, aliphatic / aromatic copolyesters have a difficulty in processing due to a slow cooling rate, and there is a strong tendency to stick to each other during film production, so that there is a high possibility that defects such as wrinkles are likely to occur during winding, However, the plastic bag manufactured from this is not worth the product because it does not come out as a dog.

As another conventional technique, Korean Patent Laid-Open Publication No. 2001-0032052 discloses a polylactic acid (or a copolymer thereof) which is obtained by condensation polymerization using adipic acid as a dicarboxylic acid and 1,4-butanediol as a succinic acid and an aliphatic diol 30 to 70 parts by weight of Bionolle 3001, a trade name of Showa High Polymer Co., Ltd., which is a polybutylenesulfonate copolymer, was added to 100 parts by weight of polylactic acid, and then the two components were compounded using an extruder to improve the physical properties. Korean Patent Registration No. 10-428687 discloses a method for producing a biodegradable resin composition by preparing a composition of 35 to 65 parts by weight of polylactic acid based on 100 parts by weight of an aliphatic polyester and an aliphatic / aromatic copolyester through compounding using a twin-screw extruder . In this case, due to the high melting point of the polylactic acid in the compounding process of the polylactic acid (or the copolymer thereof) and the polybutylene succinate (or the copolymer thereof), the thermal stability of the resin produced upon extrusion at a high temperature is significantly reduced, The mechanical properties of the produced resin are also reduced.

Another conventional technique is a method for preparing an aliphatic or aliphatic / aromatic copolyester by adding an oxazoline compound and a carbodiimide compound to an esterification reaction or a polycondensation reaction in Korean Patent Registration Nos. 2011-0054172 and 2011-0054174 Lt; / RTI > In this method, an oxazoline compound and a carbodiimide compound capable of causing gelation in the reaction process are simultaneously used. The resin composition prepared by this method is not easy to control the reaction to gelation in the reaction process, and even in the case of the resin composition prepared by the process control, the gel composition of the resin composition has gelated ultrahigh molecular weight molecules. , fish-eye, etc., resulting in poor machining quality and poor surface appearance of the product.

In addition, as described in the prior art, the use of a polyfunctional carboxylic acid, a polyfunctional diol and the occurrence of the above-mentioned problems due to gelation when an isocyanate compound is used in the reaction become more serious.

Korean Patent Application No. 10-1993-0020638 Korean Patent Application No. 10-1997-2703252 Korean Patent Registration No. 10-0642289 Korean Patent Laid-Open Publication No. 2001-0032052 Korean Patent Registration No. 10-0428687

The greatest influence on the weather resistance and storage stability of the biodegradable polyester resin composition is due to the hydrolysis occurring under the environment of use and circulation environment, and the factors affecting the hydrolysis rate of the biodegradable polyester resin There are several, but the largest endogenous factor in polyester is the carboxyl end group concentration. The hydrogen ion of the carboxyl group acts as an acid catalyst to cause a hydrolysis reaction to decompose a chain of a molecule into a short molecule having a hydroxyl group and a carboxyl terminal. This increases the number of carboxyl groups, which again acts as a self-catalyst, accelerating the rate of increase of carboxyl groups over time and accelerating the rate of hydrolysis.

In order to solve such problems, the present invention relates to a process for producing an aliphatic dicarboxylic acid or an aliphatic dicarboxylic acid and an aromatic dicarboxylic acid, The resin composition obtained through the esterification exchange reaction and the polycondensation reaction is then subjected to a chain extension reaction and a solid phase polymerization reaction to produce a biodegradable aliphatic copolyester or a biodegradable aliphatic / It is an object of the present invention to provide a biodegradable resin composition having excellent weather resistance and storage stability by producing an ester.

The biodegradable resin composition obtained by the method described above is excellent in mechanical properties and low in low molecular weight, and has low storage stability due to low carboxyl end group concentration. Therefore, in the case of workpieces manufactured therefrom, It has a long advantage.

In the present invention, the aliphatic dicarboxylic acid alone or an aliphatic dicarboxylic acid obtained by the esterification reaction of an aliphatic diol with an acid component containing an aliphatic dicarboxylic acid and an aromatic dicarboxylic acid mixed component, an esterification exchange reaction, A branched agent containing a ring in a molecular structure and having a functional group having different activities in the course of producing copolyesters or aliphatic / aromatic copolyesters is prepared, which is effective in improving the reaction rate and increasing the molecular weight while hardly causing gelation It is used as a reaction aid.

The branching agent used also increases the tearing strength and elongation of the resin composition obtained by forming side branches in the molecular structure of the resin composition, as well as a reaction site in the chain extension reaction or solid phase polymerization ). Therefore, the reaction efficiency is improved, and a resin composition having a lower acid value and a higher molecular weight than that of the aliphatic or aliphatic / aromatic copolyester resin composition prepared by conventional techniques can be produced.

 The resin composition thus obtained has an average molecular weight of 50,000 to 100,000, a weight average molecular weight of 100,000 to 300,000, an acid value of 0.1 mLmgKOH / g to 2 mgKOH / g, a melt flow index of 0.5 g / 5 g / 10 min.

The biodegradable resin composition according to the present invention is superior in mechanical properties to conventional biodegradable resin compositions and has a low resistance to hydrolysis reaction at a low carboxyl end group content, There is an excellent effect of solving the problem that the use range is limited for a long time. This promotes expansion of use of the biodegradable resin, thereby reducing the environmental pollution caused by waste plastics.

In the present invention, the aliphatic dicarboxylic acid alone or an aliphatic dicarboxylic acid obtained by the esterification reaction of an aliphatic diol with an acid component containing an aliphatic dicarboxylic acid and an aromatic dicarboxylic acid mixed component, an esterification exchange reaction, A branching agent containing a ring in a molecular structure and having a functional group having different activities in the course of producing a copolyester or an aliphatic / aromatic copolyester is prepared and used as a reaction aid for improving the reaction rate and increasing the molecular weight, Or an aliphatic / aromatic copolyester resin composition is further subjected to chain extension reaction and solid phase polymerization to obtain a copolymer having an average molecular weight of 50,000 to 100,000, a weight average molecular weight of 100,000 to 300,000 and an acid value of 0.1 mgKOH / g to 2 mgKOH / g, Thereby providing an excellent biodegradable resin composition.

In order to increase the reaction speed and increase the molecular weight, the present invention uses DL-malic acid and 1,4-cyclohexanedimethanol as an essential component, which is obtained through esterification reaction under nitrogen atmosphere, And used as a reaction aid. Formula (1) shows an example of the chemical structure of a polyfunctional compound obtained from the above reaction.

[Chemical Formula 1]

Here, x is 3 to 5.

A multifunctional monomer such as glycerol, citric acid or the like, which is a branching agent commonly used in the production of polyester, is difficult to control the reaction so that it is difficult to obtain a uniform resin composition and the rate of occurrence of defects due to gelation of the resin is high. However, Have different reaction activity of functional groups and have a long chain. Therefore, the use conditions are not so complicated and the usable range is wider than that of polyfunctional monomers due to steric hindrance in the reaction.

In addition, the polyfunctional compound having a long chain may be added at an early stage of the esterification reaction in the synthesis of an aliphatic copolyester or an aliphatic / aromatic copolyester to rapidly increase the molecular weight of the reactant by promoting bonding between the polymer chains, It has a role of improving the processability of a resin composition obtained by forming side branches in the molecular main chain to widen the molecular weight distribution.

In addition, side chain formation and ring structure are provided in the polymer structure of the resin composition to be produced, thereby improving the tear strength and elongation of the resulting resin composition and improving biodegradability.

In one embodiment, the biodegradable resin composition of the present invention comprises:

(i) subjecting DL-malic acid and 1,4-cyclohexane dimethanol to an esterification reaction to prepare a polyfunctional compound;

(ii) esterifying an aliphatic diol with an aliphatic dicarboxylic acid alone component or an acid component comprising a mixture of an aliphatic dicarboxylic acid and an aromatic dicarboxylic acid component and a glycol component in the presence of the polyfunctional compound of the step (i) Obtaining an oligomer which is a reaction and an ester exchange reaction product;

(iii) subjecting the reaction product of step (ii) to condensation polymerization to produce a resin composition;

(iv) drying the resin composition obtained in the step (iii), adding a selected compound of an isocyanate compound or a carbodiimide compound, and performing a chain extension reaction using a twin-screw extruder or a kneader;

(v) The resin composition obtained by the chain extension reaction of the step (iv) is solid-phase-combined at a temperature lower than the melting point to prepare a final resin composition.

Preferably, the present invention is a method for producing a biodegradable resin composition,

(i) subjecting a 1: 1.2 molar ratio of DL-malic acid and 1,4-cyclohexane dimethanol to the esterification reaction at 210 DEG C for 120 minutes in the presence of a catalyst to prepare a polyfunctional compound;

(ii) an aliphatic dicarboxylic acid alone or an aliphatic dicarboxylic acid and an aromatic dicarboxylic acid mixed component and an aliphatic diol as a glycol component in an amount of 1: 1.15 (i) in the presence of the polyfunctional compound obtained in the step (i) To 1: 1.5, and reacting at 190 to 210 ° C to obtain an esterification reaction and an oligomer as an ester exchange reaction product;

(iii) polycondensation of the reaction product of step (ii) in a temperature range of 235 DEG C to 250 DEG C under a degree of vacuum of less than 2 torr for 90 to 180 minutes to give a number average molecular weight of 15,000 to 30,000, a melt flow index of 190 DEG C, Obtaining a resin composition at 30 g / 10 min to 60 g / 10 min under measurement conditions;

(iv) adding the resin composition of step (iii) to a twin-screw extruder or kneader and then adding 0.05 to 0.5 parts by weight of a compound selected from an isocyanate compound or a carbodiimide compound as a chain extender, Conducting a chain extension reaction;

(v) Solid phase polymerization is carried out at a temperature of from 70 캜 to 100 캜, which is lower than the melting point of the resin composition obtained from the step (iv), to prepare a final resin composition.

In a preferred embodiment, the multifunctional compound synthesized in the above-mentioned step (i) of the present invention is obtained by introducing DL-malic acid and 1,4-cyclohexanedimethanol in a molar ratio of 1: 1.2 and reacting the catalyst with titanium butoxide or 0.05 to 0.1 g per mol of DL-malic acid to which titanium isopropoxide is added is added, and then the theoretical amount of water is completely discharged while maintaining the temperature of the reactor at 210 占 폚.

The polyfunctional compound thus prepared is used in the range of 0.1 g to 0.8 g per mole of the aliphatic dicarboxylic acid and aromatic dicarboxylic acid charged into the reactor during the synthesis of the biodegradable resin composition. If the amount of the acid component added is less than 0.1 g, there is no effect. When the amount exceeds 0.8 g, the viscosity rapidly increases. However, when the resin composition is used, The discharge of the resin composition in the reactor itself may not be possible.

In step (ii), the aliphatic (including cyclic aliphatic) dicarboxylic acid used is selected from the group consisting of succinic acid, glutaric acid, adipic acid, sebacic acid, pimelic acid, azelaic acid, cyclohexanedicarboxylic acid, Forming derivative, and the above-mentioned components may be used singly or in combination.

Further, in step (ii), a mixed component of the above-mentioned aliphatic dicarboxylic acid and aromatic dicarboxylic acid may be used as an acid component, wherein the aromatic dicarboxylic acid used is terephthalic acid, isophthalic acid, ≪ / RTI > Particularly terephthalic acid (or an ester-forming derivative thereof) is most useful, and these components can be used singly or in combination.

The molar ratio of the aliphatic dicarboxylic acid component to the aromatic dicarboxylic acid component is preferably in the range of 95: 5 to 40:60. When the content of the aromatic dicarboxylic acid exceeds 60 mol%, the biodegradability does not occur. When the content of the aromatic dicarboxylic acid is less than 5 mol%, the effect of the mixed component is hardly expected.

In another preferred embodiment, when different reaction by-products occur in the reaction when the aliphatic dicarboxylic acid and aromatic dicarboxylic acid mixed components are used as acid components in the esterification reaction and the transesterification reaction of step (ii) And the reaction proceeds.

For example, when succinic acid is used as an aliphatic dicarboxylic acid and dimethyl terephthalate is used as an aromatic dicarboxylic acid component, succinic acid reacts with aliphatic glycol to cause water to flow out as a byproduct of the reaction and methanol reacts with dimethyl terephthalate and aliphatic glycol When these two components are reacted together, the reactor column is clogged due to the competition of the two reactions.

Therefore, it is preferable to carry out the reaction in two stages. For example, after the addition of succinic acid and aliphatic glycol, a theoretical amount of water is spilled out, dimethyl terephthalate is added in the presence of esterification reaction product of succinic acid and aliphatic glycol to proceed esterification reaction, Or in the opposite order. The amount of aliphatic glycol to be added at this stage may be either the total amount used in the first step or the molar ratio divided in each step.

In step (ii), the aliphatic glycol component is an alkanediol having from 2 to 12 carbon atoms.

The alkanediol to be used is ethylene glycol, 1,2-propanediol, 1,2-butanediol, 1,4-butanediol, 1,6-hexanediol, 1,2-cyclohexanedimethanol, Although the components are good, two or more diols can be used in combination. The aliphatic glycol molar ratio charged to the aliphatic dicarboxylic acid (or an anhydride thereof) and the aromatic dicarboxylic acid (or anhydride thereof) to be used is in the range of 1: 1.15 to 1: 1.5, more preferably 1.25 To 1.35.

When the molar ratio of the aliphatic glycol introduced is less than 1.15, the reaction does not sufficiently take place and the oligomer having a low molecular weight is present in a large amount, so that a resin composition having sufficient molecular weight can not be obtained in the subsequent condensation polymerization. With the increase of the time for removing the excess glycol in the reaction step, the vacuum line of the reaction equipment is clogged to increase the defective rate.

In another preferred embodiment, the temperature range in which the esterification reaction and the transesterification reaction of step (ii) are carried out is preferably maintained at 190 캜 to 210 캜.

In another preferred embodiment, the polycondensation reaction of step (iii) is carried out at a temperature in the range of 235 DEG C to 255 DEG C under a vacuum of less than 2 torr for 90 to 180 minutes to give a number average molecular weight of 15,000 to 30,000, a melt flow index of 190 DEG C, 2,160 g to 30 g / 10 min to 60 g / 10 min. In the case of the resin composition satisfying the above-mentioned conditions, since the melt flow and the polymer chain length suitable for the chain extension reaction, which is the next step of the present reaction, are easily combined with the chain extender introduced at the terminal functional group of the resin composition, The length of the chain joined by the chain extender also has a molecular weight and molecular weight distribution suitable for plastic processing.

Unlike this, when the number average molecular weight is less than 15,000 and the melt flow index exceeds 60 g / 10 min, not only the molecular weight of the next chain reaction is increased but the chain extension due to the short chain The amount of the agent increases and gelation may occur in this process. When the number average molecular weight exceeds 30,000 and the melt flow index is less than 30 g / 10 min, the flowability of the resin composition in the chain elongation reaction is small and the possibility of bonding the functional groups of the chain extender with the resin composition is low, The molecular weight distribution is widened due to nonuniform reaction, the mechanical properties are deteriorated and the short polymer chains of the resin composition which are not reacted accelerate the subsequent hydrolysis, causing problems of quick aging and surface elution.

Step (iv) may be carried out by introducing the resin composition of step (iii) into a biaxial extruder or kneader, and then adding 0.05 to 0.5 part by weight of a compound selected from an isocyanate compound or a carbodiimide compound as a chain extender, .

As a preferred specific example, the chain extension reaction is carried out in the range of 100 ° C to 180 ° C, which is 5 ° C to 10 ° C higher than the melting point of the resin composition obtained in step (iii). In the case of the resin composition obtained in step (iii), when the chain extension reaction is carried out at a temperature higher than the above range due to a low molecular weight and a high melt flow index, the chain extension reaction rate is increased and the thermal decomposition reaction is increased, Due to the oxidation products and short polymer chains formed by the thermal decomposition reaction, the mechanical properties are deteriorated and the storage stability due to rapid hydrolysis is lowered. On the contrary, when the chain extension reaction is carried out at a temperature lower than the above-mentioned range, the resin composition is not sufficiently melted in the reaction step, so that the reaction can not sufficiently take place and the effect can not be obtained.

Another preferred embodiment uses a compound selected from an isocyanate compound and a carbodiimide compound as the chain extender used in the step (iv). The isocyanate compound used is one selected from 1,6-hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-diphenylmethane diisocyanate and 2,2'-diphenylmethane diisocyanate. Another carbodiimide compound, chain extender, is 1,3-dicyclohexylcarbodiimide, HMV-8CA sold by Nisshinbo, HMV-10B, STABILIZER 9000 from Raschig, STABILIZER 7000, bis- (2,6- Isopropyl-phenylene-2,4-carbodiimide) and poly- (1,3,5-triisopropyl-phenyl-2,4-carbodiimide).

In another preferred embodiment, the resin composition subjected to the chain extension reaction in the step (iv) has a number average molecular weight of 30,000 to 40,000, a melt flow index of 190 DEG C and 2,160 g at a measurement condition of 5 g / 10 min to 15 g / Is 3 mgKOH / g to 6 mgKOH / g.

Step (v) is subjected to solid phase polymerization at a temperature of 70 to 160 캜, which is lower than the melting point of the resin composition obtained from the step (iv), for 4 hours or more to prepare a final resin composition.

In a preferred embodiment, the solid-state polymerization in the step (v) can be carried out by using a dehumidifying dryer or a vacuum dryer in which air dehumidified by the reactor is supplied, more preferably, in a vacuum dryer capable of maintaining a vacuum state of less than 1 torr It is advantageous in shortening the time. The final resin composition obtained through the solid phase polymerization can suppress the side reaction due to the reaction at a temperature lower than the melting temperature and the carboxyl group concentration at the end of the resin composition is low so that the storage stability is improved owing to the improvement of the water- Since the content of the monomer and the low molecular weight oligomer is low and the crystallization degree increases with the increase of the molecular weight, the mechanical properties and the processing performance are improved.

In yet another preferred embodiment, the biodegradable resin composition thus prepared, which has been subjected to solid phase polymerization in the step (v), has a melting point of 90 to 170 ° C, a number average molecular weight of 50,000 to 100,000, a weight average molecular weight of 100,000 to 300,000, And an acid value of 0.5 mg / 10 min to 5 g / 10 min under the measurement conditions of an index 190 ° C and 2,160 g is 0.1 mg KOH / g to 2 mg KOH / g.

In another preferred embodiment, the catalyst may be added at the beginning or end of the esterification reaction, transesterification reaction and condensation reaction. Such a catalyst may be used in the range of 0.05 g to 0.1 g with respect to 1 mol of the acid component to be added. Specific examples of such catalysts are selected from tetrabutyl titanate, natmeacetate, antimony trioxide, dibutyl tin oxide, zinc acetate or a mixture of two or more thereof.

In another preferred embodiment, stabilizers may be added at the beginning or end of the esterification reaction, transesterification reaction and condensation reaction. Such a stabilizer is suitably used in the range of 0.05 to 0.1 part by weight per 1 mole of the acid component to be added. Such stabilizers include, but are not limited to, trimethyl phosphate, phosphoric acid, triphenyl phosphate or mixtures of two or more thereof.

The present invention relates to a process for producing a polymer having an aliphatic ring and a side chain in a molecular structure and having a melting point of 90 ° C to 130 ° C and a number average molecular weight of 50,000 to 100,000 and a weight average molecular weight of 100,00 to 300,000 And having an acid value of 0.5 mg / 10 min to 5 g / 10 min under a measurement condition of a melt flow index of 190 DEG C and 2,160 g, a biodegradable aliphatic copolyester or an aliphatic / aromatic copolyester resin composition having an acid value of 0.1 mg KOH / g to 2 mg KOH / .

≪ Preparation of multifunctional compound >

A 1 L round bottom flask was purged with nitrogen, 134.09 g of DL-malic acid, 173.05 g of 1,4-cyclohexanedimethanol and 0.1 g of titanium isopropoxide as a catalyst were introduced and then esterified at 210 DEG C for 120 minutes The reaction was allowed to proceed to sufficiently distill two moles of the theoretical yield of water, which is a by-product of the reaction, per mole of DL-malic acid to be added to prepare a polyfunctional compound.

≪ Production of biodegradable resin composition >

23.6 kg of succinic acid, 22.53 kg of 1,4-butanediol and 80 g of the prepared polyfunctional compound were added to a 100 L reactor, and the esterification reaction was carried out at 200 ° C for 120 minutes to distill out a theoretical amount of water. At this time, 10 g of tetrabutyl titanate as a catalyst and 10 g of trimethyl phosphate as a stabilizer were added. After the theoretical amount of water was drained, the temperature was elevated and the polycondensation reaction was carried out for 100 minutes under a reduced pressure of 1.5 Torr at 245 DEG C to obtain a polymer having a number average molecular weight of 18,200 and a melt flow rate of 190 g / 10 min. ≪ / RTI > In the condensation polymerization step, 10 g of tetrabutyl titanate, 10 g of antimony trioxide and 20 g of trimethyl phosphate as a stabilizer were added as a catalyst. In the next step, 50 kg of 1,6-hexamethylene diisocyanate was subjected to a chain extension reaction at 125 DEG C with a twin-screw extruder having a diameter of 58 mm in 10 kg of the reaction product obtained through the condensation polymerization reaction. The reaction product obtained through the chain extension reaction had a number average molecular weight of 33,270, a melt flow rate of 190 g / cm 2 and a gauge of 10 g / 10 min at 2,160 g, and an acid value of 3.6 mg KOH / g. Next, the reaction product obtained by the chain extension reaction was put into a solid state polymerization apparatus equipped with a vacuum pump, and solid state polymerization was carried out at 80 ° C for 8 hours to obtain a polymer having a melting point of 116 ° C, a number average molecular weight of 56,380, a weight average molecular weight of 122,908, Deg.] C, 2,160 g, and an acid value of 0.8 mgKOH / g.

≪ Production of biodegradable resin composition >

22.9 kg of succinic acid, 0.88 kg of adipic acid, 23.84 kg of 1,4-butanediol, 0.34 kg of ethylene glycol and 85 g of the polyfunctional compound prepared in [Example 1] were introduced into a 100 L reactor, and the mixture was reacted at 200 DEG C for 120 minutes The esterification reaction proceeded to distill out the theoretical amount of water. At this time, 10 g of tetrabutyl titanate as a catalyst and 10 g of trimethyl phosphate as a stabilizer were added. After the theoretical amount of water was discharged, the temperature was elevated and the condensation polymerization reaction was carried out for 118 minutes at a temperature of 245 DEG C under a reduced pressure of 1.5 Torr to obtain a polymer having a number average molecular weight of 20,370, a melt flow rate of 190 g / 10 min. ≪ / RTI > In the condensation polymerization step, 10 g of tetrabutyl titanate, 10 g of antimony trioxide and 20 g of trimethyl phosphate as a stabilizer were added as a catalyst. In the next step, 25 g of bis- (2,6-diisopropyl-phenyline-2,4-carbodiimide) was added to 10 kg of the reaction product obtained through the condensation polymerization reaction at a temperature of 120 ° C with a twin-screw extruder Respectively. The reaction product obtained through the chain extension reaction had a number average molecular weight of 33,270, a melt flow rate of 190 g / m 2, and a molecular weight of 2,160 g at 8 g / 10 min and an acid value of 3.2 mg KOH / g. Next, the reaction product obtained by the chain extension reaction was put into a solid state polymerization apparatus equipped with a vacuum pump, and solid state polymerization was carried out at 80 ° C for 12 hours to obtain a copolymer having a melting point of 110 ° C, a number average molecular weight of 59,420, a weight average molecular weight of 142,908, , A final biodegradable resin composition having an acid value of 0.77 mgKOH / g at 2.3 g / 10 min under 2,160 g was obtained.

≪ Production of biodegradable resin composition >

18.64 kg of dimethyl terephthalate, 23.84 kg of 1,4-butanediol and 30 g of the polyfunctional compound prepared in Example 1 were introduced into a 100 L reactor, and then 8 g of tetrabutyl titanate, , 8 g of trimethyl phosphate was added and the esterification reaction proceeded to distill the theoretical amount of ethanol. After 15.19 kg of adipic acid was added, secondary esterification reaction was carried out at 200 ° C. for 120 minutes to distill out a theoretical amount of water . At this time, 8 g of tetrabutyl titanate as a catalyst and 8 g of trimethyl phosphate as a stabilizer were added. After the theoretical amount of water was discharged, the temperature was elevated and the condensation polymerization was carried out for 142 minutes under a reduced pressure of 1.5 Torr at a temperature of 245 DEG C to obtain 34 g / m < 2 > at a number average molecular weight of 27,843, a melt flow index of 190 DEG C and 2,160 g, 10 min. ≪ / RTI > In the condensation polymerization step, 10 g of tetrabutyl titanate, 10 g of antimony trioxide and 20 g of trimethyl phosphate as a stabilizer were added as a catalyst. In the next step, 45 kg of 1,6-hexamethylene diisocyanate was subjected to a chain extension reaction at 120 DEG C with a twin-screw extruder having a diameter of 58 mm in 10 kg of the reaction product obtained through the condensation polymerization reaction. The reaction product obtained through the chain extension reaction had a number average molecular weight of 38,895, a melt flow rate of 190 g / cm2 and a germicidal value of 3.1 mgKOH / g under a condition of 2,160 g at 6.8 g / 10 min. The reaction product obtained by the chain extension reaction was introduced into a solid phase polymerization apparatus equipped with a vacuum pump and subjected to a solid state polymerization reaction at 100 ° C for 10 hours to obtain a polymer having a melting point of 125 ° C, a number average molecular weight of 58,534, a weight average molecular weight of 168,455, Deg.] C, 2,160 g, and an acid value of 0.48 mg KOH / g.

≪ Production of biodegradable resin composition >

18.64 kg of dimethyl terephthalate, 23.84 kg of 1,4-butanediol and 30 g of the polyfunctional compound prepared in Example 1 were introduced into a 100 L reactor, and then 8 g of tetrabutyl titanate, , 8 g of trimethyl phosphate was added and the esterification reaction proceeded to distill the theoretical amount of ethanol. Then, 12.28 kg of succinic acid was added, followed by secondary esterification at 200 ° C. for 120 minutes to distill out a theoretical amount of water. At this time, 8 g of tetrabutyl titanate as a catalyst and 8 g of trimethyl phosphate as a stabilizer were added. After the theoretical amount of water was discharged, the temperature was elevated and the condensation polymerization reaction was carried out at a temperature of 245 DEG C under a reduced pressure of 1.5 Torr for 153 minutes to obtain a polymer having a number average molecular weight of 28.546, a melt flow index of 190 DEG C under a condition of 2,160 g, 10 min. ≪ / RTI > In the condensation polymerization step, 10 g of tetrabutyl titanate, 10 g of antimony trioxide and 20 g of trimethyl phosphate as a stabilizer were added as a catalyst. In the next step, 25 kg of the carbodiimide compound STABILIZER 9000 from Raschig was subjected to a chain extension reaction at a temperature of 120 캜 with a diameter of 58 mm using a twin-screw extruder. The reaction product obtained through the chain extension reaction had a number average molecular weight of 36,230, a melt flow rate of 7.1 g / 10 min at 190 ° C. and 2,160 g, and an acid value of 3.4 mg KOH / g. The reaction product obtained by the chain extension reaction was introduced into a solid phase polymerization apparatus equipped with a vacuum pump and subjected to solid phase polymerization reaction at 100 ° C for 12 hours to obtain a polymer having a melting point of 124 ° C, a number average molecular weight of 59,351, a weight average molecular weight of 166,328, Deg.] C, 2,160 g, and an acid value of 0.41 mg KOH / g.

[Comparative Example 1]

23.62 kg of succinic acid and 24.32 kg of 1,4-butanediol were placed in a 100 L reactor, and the esterification reaction was carried out at 200 ° C for 120 minutes to distill out a theoretical amount of water. 20 g of antimony acetate, 20 g of tibutyltin oxide, 20 g of tetrabutyl titanate and 20 g of trimethyl phosphate as a stabilizer were added as a catalyst. After the theoretical amount of water was drained, the temperature was elevated and the condensation polymerization reaction was carried out for 150 minutes under a reduced pressure of 250 ° C to 2.0 Torr or lower. Ten minutes before the product discharge, 2,2-bis- (2-oxazoline) , 20 g of HMV-8CA (Nisshinbo, Japan) as a carbodiimide compound, and the mixture was discharged for 10 minutes. The resin thus obtained had a melting point of 115 占 폚, a number average molecular weight of 31,215, a weight average molecular weight of 72,521, a melt flow rate of 190 占 폚 and 2,160 g at 8.3 g / 10 min and an acid value of 6.2 mgKOH / g.

[Comparative Example 2]

21.9 kg of succinic acid, 2.92 kg of adipic acid and 24.32 kg of 1,4-butanediol were placed in a 100 L reactor, and 0.1 g of tetramethyl titanate was added thereto. The esterification reaction was carried out at 200 ° C. for two hours to distill out a theoretical amount of water . 20 g of antimony acetate, 20 g of tibutyltin oxide, 20 g of tetrabutyl titanate and 40 g of trimethyl phosphate as a stabilizer were added as a catalyst. After the theoretical amount of water was drained, the temperature was elevated and the condensation polymerization reaction was carried out for 150 minutes under a reduced pressure of 250 ° C to 2.0 Torr or lower. Ten minutes before the product discharge, 2,2-bis- (2-oxazoline) 80 g was added, and the mixture was discharged for 10 minutes. The resin thus obtained had a melting point of 98 占 폚, a number average molecular weight of 35,612, a weight average molecular weight of 79,325, a melt flow index of 190 占 폚 and 2,160 g at 9.8 g / 10 min and an acid value of 5.8 mgKOH / g.

[Comparative Example 3]

18.64 kg of dimethyl terephthalate and 121.6 kg of 1,4-butanediol were charged into a 100 L reactor, 20 g of tetramethyl titanate was added, and the esterification reaction was carried out at 200 DEG C for 120 minutes to distill methanol of a theoretical amount, After 15.2 kg of acid was added, the reaction temperature was fixed at 200 캜 and water was flowed out. 20 g of antimony acetate, 20 g of tibutyltin oxide, 20 g of tetrabutyl titanate and 40 g of trimethyl phosphate as a stabilizer were added as a catalyst. After the theoretical amount of water was drained, the temperature was elevated and the condensation polymerization reaction was carried out for 150 minutes under a reduced pressure of 250 ° C to 2.0 Torr or lower. Ten minutes before the product discharge, 2,2-bis- (2-oxazoline) And 20 g of HMV-8CA (Nisshinbo, Japan) as a carbodiimide compound were added, and the mixture was discharged for 10 minutes. The resin thus obtained had a melting point of 125 占 폚, a number average molecular weight of 34,168, a weight average molecular weight of 81,523, a melt flow rate of 190 占 폚 and 2,160 g under conditions of 8.2 g / 10 min and an acid value of 3.5 mg KOH / g.

[Comparative Example 4]

18.64 kg of dimethyl terephthalate and 121.6 kg of 1,4-butanediol were charged into a 100 L reactor and 20 g of tetramethyl titanate was added thereto. The esterification reaction was carried out at 200 ° C for two hours to distill out a theoretical amount of methanol, After 15.2 kg of acid was added, the reaction temperature was fixed at 200 캜 and water was flowed out. 20 g of antimony acetate, 20 g of tibutyltin oxide, 20 g of tetrabutyl titanate and 40 g of trimethyl phosphate as a stabilizer were added as a catalyst. After the theoretical amount of water was drained, the temperature was elevated and the condensation polymerization reaction was carried out for 150 minutes under a reduced pressure of 250 ° C to 2.0 Torr or lower. Ten minutes before the product discharge, 2,2-bis- (2-oxazoline) And 20 g of HMV-8CA (Nisshinbo, Japan) as a carbodiimide compound were added, and the mixture was discharged for 10 minutes. The resin thus obtained had a melting point of 124 占 폚, a number average molecular weight of 34,463, a weight average molecular weight of 75,352, a melt flow rate of 190 占 폚 and 2,160 g at 9.2 g / 10 min and an acid value of 4.6 mgKOH / g.

[Test Example 1]

≪ Storage stability test and biodegradability test of resin composition >

Each of the samples of the resin compositions of Comparative Examples 1 to 4, which were constructed in the same manner as in Examples 1, 2, 3 and 4, and the conventional manufacturing method, was allowed to stand at a temperature of 25 ° C. and a relative humidity of 75% A change in the number-average molecular weight was examined by comparing the measured value with the initial value, and the change with time was also confirmed. Further, in Examples 1, 2, 3 and 4 and Comparative Example of Resin Composition A sample of 30 μm thick pressing film was prepared by using Examples 1 to 4, and then the sample was left under constant temperature and humidity conditions of 25 ° C. and 75% relative humidity, and the tensile strength and elongation were measured every 6 months. The change was confirmed.

 The number average molecular weight was measured by gel permeation chromatography at a temperature of 35 ° C. using a device equipped with a column packed with polystyrene. The developing solvent was chloroform, the concentration of the sample was 5 mg / mL, the flow rate of the solvent Was carried out at a rate of 1.0 mL / min. The tensile strength and the elongation were measured according to ASTM D 638, a standard test method of the US, and the results are shown in Table 1 below.

Item Number average molecular weight Tensile strength (kgf / cm2) Elongation (%) Early 6 months
after After 12 months Early 6 months
after After 12 months Early 6 months
after After 12 months Example 1 56,380 52,997 49,727 350 342 311 175 167 125 Example 2 59,420 57,043 51,694 325 313 299 225 223 184 Example 3 58,534 57,363 50,339 292 288 268 472 470 375 Example 4 59,351 57,451 53,000 283 272 251 425 418 352 Comparative Example 1 31,215 28,692 21,288 280 228 119 150 75 0 Comparative Example 2 35,612 30,626 20,797 234 194 101 300 125 10 Comparative Example 3 34,168 30,477 22,960 245 218 116 350 150 12.5 Comparative Example 4 34,463 30,325 20,574 238 207 103 325 175 15

As shown in Table 1, the biodegradable resin composition of the present invention has a number average molecular weight of more than 50,000, showing a higher degree of polymerization than conventional resins, and superior in tensile strength and elongation than conventional resins.

[Test Example 2]

≪ Chemical properties and biodegradability test of resin composition >

The resin compositions of Examples 1, 2, 3 and 4 and Comparative Examples 1 to 4, which were constructed in the same manner as in Example 1, were used to measure the melting point. Using a differential scanning calorimeter, The melt flow index was measured under the conditions of 190 ° C and 2,160 g according to ASTM D1238, and the results are shown in Table 2 below. The acid value of the resin composition prepared in the above Examples and Comparative Examples was dissolved in chloroform. One or two drops of the phenolphthalein indicator were added to the solution, and the acid value was measured by an acid-base titration method using an ethanol solution in which KOH was dissolved at a concentration of 0,1 And the value was obtained by the calculation of the equation of FIG.

(Acid value calculation formula)

(Consumption of ethanol solution (mL) - basis test (mL)) x 0.1 N x 56.11 / mass of sample = (acid value) mg KOH / g

The biodegradability was evaluated by using a resin composition prepared in the above Examples and Comparative Examples, and a pressing film having a thickness of 30 袖 m was produced. The pressing film was collected at a depth of 30 cm from the soil surface and recovered after 12 months. The soil used was a mixture of weeds and culture soil in a weight ratio of 1: 1.

Table 2 below shows the melting point, melt flow index, acid value and biodegradability of the resin compositions prepared in Examples and Comparative Examples.

Item Melting point
(° C) Melt flow index
(g / 10 min) Acid value
(mgKOH / g) Biodegradability
(%) Example 1 116 4.8 0.80 81.5 Example 2 110 2.3 0.77 88.7 Example 3 125 1.8 0.48 82.1 Example 4 124 0.9 0.41 83.3 Comparative Example 1 115 8.3 6.2 82.3 Comparative Example 2 98 9.8 5.8 89.4 Comparative Example 3 125 8.2 3.5 81.9 Comparative Example 4 124 9.2 4.6 80.5

As shown in [Table 1] and [Table 2], the biodegradable resin composition of the present invention has a higher molecular weight and a lower melt flow index than the biodegradable resin compositions of similar components prepared by conventional techniques, It has excellent and low concentration of carboxyl end groups in molecular structure, and is excellent in resistance to hydrolysis during storage, distribution and use, so the change over time is small and the service life is prolonged under daily use environment.

Claims (7)

Esterification reaction and ester exchange reaction of an aliphatic dicarboxylic acid alone component or an acid component containing an aliphatic dicarboxylic acid and an aromatic dicarboxylic acid mixed component with an aliphatic diol, a condensation polymerization reaction, a chain extension reaction and a solid phase polymerization In an aliphatic copolyester or an aliphatic / aromatic copolyester obtained through a sequential reaction of the reaction, in the esterification reaction and the transesterification reaction, a compound represented by the following formula A biodegradable resin having excellent weather resistance and storage stability, characterized by exhibiting a number average molecular weight of 50,000 or more and an acid value of 0.1 mgKOH / g to 2 mgKOH / g by using the displayed polyfunctional compound as a reaction aid for improving the reaction rate and increasing the molecular weight Composition
[Chemical Formula 1]

Here, x is 3 to 5.
The method according to claim 1,
The multifunctional compound represented by the formula (1) is obtained by subjecting DL-malic acid and 1,4-cyclohexanedimethanol to an esterification reaction under a nitrogen atmosphere to obtain a biodegradable resin composition
The method according to claim 1,
Wherein the aliphatic dicarboxylic acid is selected from the group consisting of succinic acid, glutaric acid, adipic acid, sebacic acid, pimelic acid, azelaic acid, cyclohexanedicarboxylic acid which is a cyclic aliphatic dicarboxylic acid, A biodegradable resin composition excellent in weather resistance and storage stability

The method according to claim 1,
Wherein the aromatic dicarboxylic acid is at least one selected from the group consisting of terephthalic acid, isophthalic acid, 2,6-naphthoic acid, and ester-forming derivatives thereof; and a biodegradable resin composition
The method of claim 1, wherein
Wherein the mixing ratio of the aliphatic dicarboxylic acid and the aromatic dicarboxylic acid mixture is 95: 5 to 40:60 in terms of molar ratio. The biodegradable resin composition excellent in weatherability and storage stability
(i) subjecting DL-malic acid and 1,4-cyclohexane dimethanol to an esterification reaction to prepare a polyfunctional compound represented by Formula 1;
[Chemical Formula 1]

Here, x is 3 to 5.
(ii) reacting an aliphatic dicarboxylic acid alone or an aliphatic dicarboxylic acid and an aliphatic dicarboxylic acid with an aliphatic diol in the presence of the polyfunctional compound prepared in the step (i) Preparing an oligomer which is a reaction product and an ester exchange reaction product;
(iii) subjecting the reaction product prepared in the step (ii) to condensation polymerization to prepare a resin composition;
(iv) introducing the resin composition prepared in the step (iii) into a biaxial extruder or kneader, and then introducing a selected compound selected from an isocyanate compound or a carbodiimide compound as a chain extender into a chain extension reaction;
(v) solid-phase polymerizing the resin composition prepared in the step (iv) at a temperature lower than the melting point of the resin composition. A method for producing this excellent biodegradable resin composition
The method according to claim 6,
(i) DL-malic acid and 1,4-cyclohexanedimethanol in a molar ratio of 1: 1.2 in the presence of a catalyst are subjected to an esterification reaction at 210 DEG C for 120 minutes to obtain a polyfunctional compound represented by the formula Producing;
(ii) reacting an aliphatic dicarboxylic acid alone or an acid component comprising an aliphatic dicarboxylic acid and an aromatic dicarboxylic acid mixed component with an aliphatic diol at a molar ratio of 1: 1.15 (i) in the presence of the polyfunctional compound prepared in the step To 1: 1.5, and reacting at 190 to 210 ° C to obtain an esterification reaction and an oligomer as an ester exchange reaction product;
(iii) condensing the reaction product prepared in the step (ii) in a temperature range of 235 ° C to 250 ° C under a degree of vacuum of less than 2 torr for 90 minutes to 180 minutes to give a number average molecular weight of 15,000 to 30,000, g to 10 g / 10 min to 60 g / 10 min.
(iv) adding the resin composition prepared in the step (iii) to a twin-screw extruder or kneader and then adding 0.05 to 1 part by weight of a compound selected from an isocyanate compound or a carbodiimide compound as a chain extender, Chain extending reaction in the range;
(v) solid-phase-polymerizing the resin composition prepared in the step (iv) at a temperature of 70 ° C to 160 ° C, which is lower than the melting point, to obtain a biodegradable resin composition excellent in weatherability and storage stability Way