KR101691703B1 - Preparing method of a foam using biodegradable polyester resin composition - Google Patents

Abstract

Disclosed is a method for producing a polyester foam having excellent foamability and product formability during the foaming process while remarkably improving the foaming ratio by using a biodegradable resin composition having a specific physical property as a resin composition for foaming in a method for producing a foam using a biodegradable resin . The present invention relates to a process for preparing an oligomer by esterifying a composition comprising an aliphatic dicarboxylic acid and an aliphatic diol at a molar ratio of 1: 1 to 1: 2 at 180 to 220 ° C for 1 to 5 hours. 0.0001 to 0.01 mole of the titanium-based catalyst based on 1 mole of the aliphatic dicarboxylic acid and 0.1 to 1 mole of the phosphorus-based thermal stabilizer based on 1 mole of the titanium-based catalyst. The oligomer is reacted at 230 to 270 ° C for 1 to 5 hours at 2 torr To produce a polyester resin; And a step of adding and melt-mixing a foaming agent to the polyester resin and extruding the polyester resin.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for producing a foam using a biodegradable polyester resin composition,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for producing a foam, and more particularly, to a method for producing a foam using a biodegradable polyester resin composition.

Conventional general plastics have excellent mechanical properties, chemical resistance and durability and are widely used in everyday life. However, they have a disadvantage in that they can not be returned to nature when they are disposed of after use. The disposable products of plastic materials, which are in rapid increase in demand in recent years, are often left untreated because they are not recovered smoothly. Agricultural films are buried in the soil, which hinders the growth of crops. As the environmental pollution caused by plastic waste becomes a social problem, development of decomposable plastics decomposing naturally at the time of disposal after use is actively being carried out. Degradable plastics are classified into biodegradable, biodegradable, and photodegradable according to the decomposition mechanism, and can be classified into microbial production type, natural product utilization type, and synthetic polymer type depending on the production route.

Among synthetic polymers, aliphatic polyester resins are known to be completely biodegradable. For example, poly (butylene succinate), a commercially available polymer, can be polymerized using 1,4-butanediol and succinic acid as monomers, and related research and product development has been completed. In recent years, biosuccinic acid has been produced from biomass raw materials, and sustainable environmentally friendly biodegradable resins have been actively developed.

On the other hand, there is a growing interest in polyester foams in recent years. Polyesters have a somewhat higher density (about 1.33 g / cm 3) than other polymers, and it is desirable to foam to reduce the weight of films, sheets, food containers, etc., The market potential of polyester foam is high because it has insulation ability.

However, the aliphatic polyester having biodegradability generally has a low melting point or a low melt viscosity, and therefore has low heat resistance and mechanical strength. Further, since the crystallization speed is slow, there is a drawback that a drawdown occurs at the time of molding or a sufficient expansion ratio is not obtained.

Korean Patent Laid-Open Publication No. 2014-0016548 discloses a resin composition for foaming comprising a biodegradable resin and a method for producing a foam, wherein a biodegradable polyester resin to which a monomer containing a double bond is bonded by a resin composition for foaming is dissolved in ethylene- Discloses a technique for improving the compatibility with an ethylene-vinyl acetate resin by applying it to a resin. However, the content of the biodegradable polyester contained in the composition is about 20 to 50% by weight, have.

Korean Unexamined Patent Publication No. 2007-0005603 discloses a method for producing a foamed article having excellent moldability by using a foam sheet made of a biodegradable resin. The foamed additive is added to the aliphatic polyester resin to optimize the foaming conditions, Discloses a technique for producing an excellent foamed article, but it is focused on a suitable foaming condition, and there is no great implication on the relation between the foamed article and the resin composition.

DISCLOSURE Technical Problem Accordingly, the present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a method for producing a foamed product using a biodegradable resin, in which a biodegradable resin composition having a specific physical property is used as a resin composition for foaming, And to provide a process for producing a polyester foam excellent in moldability and the like.

In order to solve the above problems, the present invention provides a process for preparing an oligomer by esterifying a composition comprising an aliphatic dicarboxylic acid and an aliphatic diol at a molar ratio of 1: 1 to 1: 2 at 180 to 220 ° C for 1 to 5 hours step; 0.0001 to 0.01 mole of the titanium-based catalyst based on 1 mole of the aliphatic dicarboxylic acid and 0.1 to 1 mole of the phosphorus-based thermal stabilizer based on 1 mole of the titanium-based catalyst. The oligomer is reacted at 230 to 270 ° C for 1 to 5 hours at 2 torr To produce a polyester resin; And a step of adding and melt-mixing a foaming agent to the polyester resin and extruding the polyester resin.

And wherein the esterification reaction is a non-catalytic thermal esterification reaction.

The aliphatic dicarboxylic acid may be selected from the group consisting of malonic acid, succinic acid, maleic acid, glutaric acid, adipic acid, pimelic acid, Characterized in that it is at least one selected from the group consisting of suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, anhydrides or derivatives thereof, Ester-based foam.

Also, the aliphatic diol is at least one member selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, 1,4-butanediol, neopentyl glycol, 1,2-cyclohexanediol, , 2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, tetramethyl cyclobutanediol, 1,6-hexanediol and 1,10-decanediol And at least one polyester-based foam.

The titanium-based catalyst may be at least one selected from the group consisting of tetraisopropyl titanate, tetrabutyl titanate, tetrabutyl titanate, tetraethylenetitanate, tetrastearyl titanate, and titanium acetoacetate. A method for producing a polyester-based foam is provided.

Also, the phosphorus thermal stabilizer is at least one selected from the group consisting of monomethyl phosphate, trimethyl phosphate, triethyl phosphate and triphenyl phosphate.

The condensation polymerization is terminated when the viscosity of the reactant is 10 to 30 Nm on the basis of the torque value.

The polyester resin preferably has a weight average molecular weight (Mw) of 170,000 to 210,000, a number average molecular weight (Mn) of 70,000 to 110,000, a polydispersion index (PDI) of 1.7 to 2.2 and a melt index 0.1 to 30 g / 10 min and an intrinsic viscosity of 1 to 1.8 dl / g.

(NH ₄ ) ₂ CO ₃ ), ammonium bicarbonate (NH ₄ HCO ₃ ), ammonium nitrite (NH ₄ NO ₂ ), and the like, and the chemical foaming agent may be selected from the group consisting of sodium bicarbonate (NaHCO ₃ ), ammonium carbonate ), Sodium borohydride, azodicarboxylic acid amide (ADCA), azobisisobutyronitrile (AIBN), oxybis (benzene sulfonyl hydrazide) (OBSH), dinitro (DPT), p-toluene sulfonyl hydrazide (TSH), and p-toluene sulfonyl semicarbazide (PTSS), in the group consisting of pentaerythritol tetrakis And the physical foaming agent is at least one selected from the group consisting of aliphatic hydrocarbons, cyclobutanes, cyclopentane, cyclohexane, halogenated hydrocarbons, carbon dioxide, air, nitrogen, steam, methane and ethylene Provides a method for producing a polyester-based foam.

And a stabilizer and a nucleating agent are mixed with the polyester resin thus prepared.

Also, the stabilizer is at least one selected from the group consisting of a phenolic stabilizer, an amine stabilizer, a phosphorus stabilizer, and a sulfur stabilizer.

And the nucleating agent is at least one selected from the group consisting of talc, silica, kaolin and clay as an inorganic nucleating agent.

And 0.1 to 30 parts by weight of the foaming agent, 0.00001 to 0.001 part by weight of the stabilizer, and 0.1 to 5 parts by weight of the nucleating agent are mixed with 100 parts by weight of the polyester resin prepared above .

And the extrusion is carried out at a temperature of 125 to 160 ° C at the extrusion portion and at a temperature of 115 to 135 ° C at the die portion.

According to the present invention, a foam is produced by using a biodegradable polyester resin composition having a specific molecular weight, a polydispersity index, a melt index and an intrinsic viscosity, thereby remarkably improving the expansion ratio, It is possible to provide a method of manufacturing such a superior polyester foam.

1 is a photograph showing a foam produced according to Example 3 of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. Throughout the specification, when an element is referred to as "including " an element, it means that it can include other elements, not excluding other elements, unless specifically stated otherwise.

The present invention relates to a process for preparing an oligomer by esterifying a composition comprising an aliphatic dicarboxylic acid and an aliphatic diol at a molar ratio of 1: 1 to 1: 2 at 180 to 220 ° C for 1 to 5 hours. 0.0001 to 0.01 mole of the titanium-based catalyst based on 1 mole of the aliphatic dicarboxylic acid and 0.1 to 1 mole of the phosphorus-based thermal stabilizer based on 1 mole of the titanium-based catalyst. The oligomer is reacted at 230 to 270 ° C for 1 to 5 hours at 2 torr To produce a polyester resin; And a step of adding and melt-mixing a foaming agent to the polyester resin and extruding the polyester resin. First, the manufacturing process of the foam polyester resin composition used in the method of manufacturing the foam according to the present invention will be described in detail.

The polyester resin composition for foaming according to the present invention comprises a step of preparing an oligomer by subjecting a composition containing an aliphatic dicarboxylic acid (anhydride or a derivative thereof) and an aliphatic diol to an esterification reaction, And condensation polymerization of the oligomer in the presence of a titanium-based catalyst and a phosphorus-based thermal stabilizer.

The esterification reaction is a step of esterifying an aliphatic dicarboxylic acid and an aliphatic diol to prepare an oligomer. The aliphatic dicarboxylic acid and aliphatic diol are contained in a molar ratio of 1: 1 to 1: 2, May be contained in a molar ratio of 1: 1 to 1: 1.5, and more preferably in a molar ratio of 1: 1 to 1: 1.2. The reaction efficiency is good in the above-mentioned molar ratio range, and is advantageous in view of foamability and moldability of the polyester resin finally produced.

The aliphatic dicarboxylic acid may be, for example, malonic acid, succinic acid, maleic acid, glutaric acid, adipic acid, pimelic acid, At least one selected from the group consisting of sulfuric acid, sulfuric acid, sulfuric acid, sulfuric acid, sulfuric acid, sulfuric acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, , And succinic acid can be preferably used as a monomer in consideration of foaming use.

In the present invention, the esterification reaction step is a non-catalytic heating thermal esterification reaction, and the raw materials can be reacted at a constant temperature without using a catalyst. By performing the esterification reaction without using a catalyst, thermal stability of oligomers and polyester resins produced can be ensured, color discoloration can be minimized, and the foaming magnification can be maximized during foaming. In view of this point, the esterification reaction can be carried out at 180 to 220 ° C, preferably 190 to 210 ° C, more preferably 195 to 205 ° C. When the esterification reaction temperature is lower than 180 ° C, it is difficult to discharge by-products such as water and the reactivity of the monomer is low, and the polymerization time may increase. When the esterification reaction temperature is more than 220 ° C, pyrolysis of the ester- May be overdosed as by-products.

The esterification reaction may be carried out for 1 to 5 hours, preferably for 1 to 3 hours, more preferably for 1.5 to 2.5 hours. If the esterification reaction time is shortened, the process efficiency and production rate can be improved. However, if the reaction time is too short, the synthesis time becomes insufficient and the oligomer produced can not have a sufficient molecular weight. And the apparatus such as the reactor tube may be clogged. On the other hand, if the esterification reaction time is too long, it may be difficult to obtain an oligomer having an appropriate molecular weight and physical properties, and reactivity of the oligomer to be synthesized may deteriorate, resulting in deterioration of physical properties and workability, such as molecular weight and foamability of the final polyester resin.

In the present invention, the aliphatic diol is not particularly limited, and examples thereof include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, 1,4-butanediol, neopentyl glycol, 1,2-cyclohexanediol , 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, tetramethylcyclobutanediol, 1,6- Decanediol and the like can be used. However, 1,4-butanediol is used for the improvement of the molecular weight range and the physical properties of the final polyester resin, in particular the expansion ratio, foaming property and moldability, depending on the degree of polymerization of the oligomer produced by the reaction with the above-mentioned aliphatic dicarboxylic acid Is most preferable.

The oligomer formed through the above esterification reaction may have a number average molecular weight of 1,700 to 2,200, a weight average molecular weight of 2,900 to 3,800 and a polydispersion index (PDI) of 1.6 to 1.9, preferably a number average molecular weight of 1,900 to 2,100 , A weight average molecular weight of 3,300 to 3,600 and a polydispersion index (PDI) of 1.7 to 1.8. When the molecular weight and the polydispersity index range are satisfied, satisfactory physical properties such as heat resistance and tensile strength required for a polyester resin formed by condensation polymerization of an oligomer are satisfied, and properties such as biodegradability, foaming property and moldability And deterioration of workability can be prevented.

Next, the polycondensation reaction is polycondensation of an oligomer formed by the esterification reaction to produce a polyester resin, which is performed in the presence of a titanium-based catalyst and a phosphorus-based thermal stabilizer.

The titanium-based catalyst may be any of those conventionally known in the art to which the present invention pertains. Therefore, the composition is not particularly limited, but is preferably tetraisopropyl titanate, tetrabutyl titanate, tetrabutyl titanate, Tetrastearyl titanate, titanium acetoacetate and the like can be used, and tetrabutoxy titanate can be more preferably used.

At this time, it is preferable that the content of the titanium-based catalyst is determined within a range capable of inducing a minimum amount of polycondensation reaction, suppressing side reactions, securing proper reaction rate, foaming property of the final polyester resin and prevention of discoloration Do. Therefore, the reaction is carried out in the presence of 0.0001 to 0.01 mol of a titanium-based catalyst based on 1 mol of the aliphatic dicarboxylic acid used in the esterification reaction, preferably 0.0005 to 0.002 mol of the titanium-based catalyst. If the content of the titanium-based catalyst is less than 0.0001 mol, the activity as a catalyst may be lost and the molecular weight may be limited. However, when the amount of the titanium-based catalyst is more than 0.01 mol, the reaction rate may be improved, can do.

In order to alleviate the thermal decomposition and side reaction of the resin which can be caused by the progress of the reaction in the condensation polymerization step, a phosphorus-based thermal stabilizer is used together with the titanium-based catalyst. As the phosphorus thermal stabilizer, monomethyl phosphate, trimethyl phosphate, triethyl phosphate, triphenyl phosphate and the like can be used, and preferably triethyl phosphate can be used.

In this case, the content of the phosphorus-based thermal stabilizer may be determined within a range that does not affect the physical properties of the resin, while ensuring a minimum effect by the addition of the stabilizer. The content of 0.1 to 1 mol per mol of the titanium- Can be used in an amount of 0.4 to 0.6 mol.

In the present invention, the polycondensation step is carried out at a reaction temperature of 230 to 270 ° C for 1 to 5 hours, preferably 240 to 260 ° C for 2 to 4 hours, and when the polycondensation reaction temperature is lower than 230 ° C, Is not preferable because the polymerization time is increased. If it exceeds 270 DEG C, the resultant polymer is thermally decomposed, which is not preferable.

At this time, the condensation polymerization is terminated when the viscosity of the reactant is 10 to 30 Nm on the basis of the torque value, so that it has an optimal molecular weight level, so that excellent foaming performance can be obtained in the subsequent foaming process.

In the present invention, the polycondensation reaction can be carried out by dividing the polymerization temperature into two reaction temperatures in order to reduce the yellowing of the polymer during the condensation polymerization, together with the maintenance of the improved foaming properties. That is, the initial condensation polymerization can be carried out at a temperature of 240 to 260 ° C, preferably 245 to 255 ° C (first condensation polymerization step), and then 220-240 ° C, preferably 225-235 ° C Lt; 0 > C (second polycondensation step). Through such a stepwise reaction, it is possible to maintain the reaction temperature higher than a certain level at the initial stage of the condensation polymerization to improve the reactivity and the polymerization rate. In the second half of the reaction, the reaction temperature is lowered to increase the viscosity of the polymer, To produce a polyester resin of excellent color.

In this case, the reaction is carried out to a certain level in the first polycondensation step and then the reaction temperature is gradually lowered to start the second polycondensation step within a certain temperature range. It is important to switch the condensation polymerization step in the optimum viscosity range of the polymerized product. Accordingly, the first polycondensation step is carried out in such a manner that the viscosity of the reactant is terminated when the torque value is 5 to 20 Nm, preferably 10 to 15 Nm, and then the reaction temperature is lowered and the viscosity of the reactant is 15 to 30 Nm , Preferably from 20 to 25 Nm, the second polycondensation step can be started. Also, the condensation polymerization reaction time may vary according to the amount of the catalyst and the stabilizer used. However, considering the viscosity change of the polymer according to the reaction temperature condition, the first condensation polymerization step is performed for 0.5 to 2 hours, preferably 1 To 1.5 hours, and the second polycondensation step can be carried out for 1 to 3 hours, preferably 1.5 to 2.5 hours.

On the other hand, the condensation polymerization step can be carried out under a pressure condition of less than 760 torr. That is, the reaction is carried out under vacuum depressurization conditions to accelerate the condensation polymerization reaction, thereby obtaining a polyester resin having sufficient foam performance, molecular weight and mechanical properties. At this time, it is preferable that the vacuum decompression is performed under a reduced pressure of 2 torr or less, and most preferably, under a condition of 0.5 torr or less. If the reduced pressure is more than 2 Torr, it is not advantageous to remove excessively charged diol compound and other unreacted monomers, and the polymerization time may be increased. In particular, the foaming performance may not be satisfactory. It is practically difficult to lower the pressure to less than 0.1 torr. Therefore, it is preferable to keep the vacuum decompression condition as low as possible.

The polyester resin for foaming to be produced by the above process may have a weight average molecular weight (Mw) of 170,000 to 210,000, preferably 180,000 to 200,000 and a number average molecular weight (Mn) of 70,000 to 110,000, (190 占 폚, 2.16 kg load) of 0.1 to 30 g / 10 min, preferably 10 to 20 g / 10 min, and a polydispersity index (PDI) of 1.7 to 2.2, preferably 1.8 to 2.1. 10 min, and an intrinsic viscosity of 1.5 to 1.7 dl / g.

The foamable polyester resin produced according to the present invention has a foam density of 0.01 to 0.8 g / cm 3, preferably 0.01 to 0.6 g / cm 3, more preferably 0.01 to 0.4 g / cm 3, Preferably 0.01 to 0.3 g / cm < 3 >.

In the present invention, the polyester resin for foaming may be further subjected to the steps which are conventionally performed in the technical field of the present invention before or after the above-mentioned steps in addition to the above-mentioned steps, The method is not limited. Hereinafter, the production of the foamed article using the foamable polyester resin will be described in detail.

The biodegradable polyester foam is prepared by adding a foaming agent to the foamable polyester resin prepared as described above, and melt-mixing and extruding the foamed polyester resin.

The foaming agent is not particularly limited, and known chemical foaming agents and physical foaming agents may be used. That is, examples of the chemical foaming agent include sodium bicarbonate (NaHCO ₃ ), ammonium carbonate ((NH ₄ ) ₂ CO ₃ ), ammonium bicarbonate (NH ₄ HCO ₃ ), ammonium nitrite (NH ₄ NO ₂ ), sodium borohydride (ADCA), azobisisobutyronitrile (AIBN), oxybis (benzene sulfonyl hydrazide) (OBSH), dinitro pentamethylene tetramine (DPT), p-toluene sulfonyl hydrazide (TSH), and p-toluene sulfonyl semicarbazide (PTSS) can be used The physical foaming agent may be at least one selected from the group consisting of aliphatic hydrocarbons, cyclobutanes, cyclopentane, cyclohexane, halogenated hydrocarbons, carbon dioxide, air, nitrogen, steam, methane and ethylene.

The foaming agent may be used in an amount of 0.1 to 30 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the polyester resin. If the content of the foaming agent is less than 0.1 parts by weight, the foaming magnification may be low. If the foaming agent content is more than 30 parts by weight, improvement of the foaming magnification may be limited.

In the present invention, a stabilizer for preventing oxidation due to deterioration upon extrusion foaming and a nucleating agent for increasing crystallinity may be further added to the polyester resin prepared before the foaming process by adding a foaming agent.

Examples of the stabilizer that may be used herein include at least one selected from the group consisting of a phenolic stabilizer, an amine stabilizer, a phosphorus stabilizer, and a sulfur stabilizer. Examples of the stabilizer include talc, silica, kaolin and clay At least one selected from the group consisting of Preferably, a phenolic stabilizer is used as the stabilizer, and talc as a nucleating agent of a plate-like structure favorable for nucleophilic action can be used as the nucleating agent.

The stabilizer and the content of the nucleating agent are preferably 0.00001 to 0.001 parts by weight (0.1 to 10 parts by weight) of the stabilizer and 0.1 to 5 parts by weight of the nucleating agent per 100 parts by weight of the polyester resin, 0.00005 to 0.0005 parts by weight (0.5 to 5 parts by weight) More preferably 0.5 to 2 parts by weight.

A stabilizer and a nucleating agent are added to the polyester resin to prepare a resin composition for foaming, and a foaming agent is added and melt mixed, followed by extrusion to produce a foam. At this time, it is possible to control through the temperature gradient in the extruder cylinder in order to smoothly transfer the melted mixture and to make an optimal foaming shape. In other words, in the case of the extruded portion, the melting temperature of the polyester resin is controlled to + 25 ° C to 35 ° C, and in the die portion where foaming occurs, the polyester resin can be controlled to the melting temperature of ± 10 ° C.

The foam thus produced has a density of 0.01 to 0.8 g / cm 3, preferably 0.01 to 0.6 g / cm 3, more preferably 0.01 to 0.4 g / cm 3, and most preferably 0.01 to 0.3 g / cm 3 So that it can be realized with an excellent expansion ratio. The foamed molded article produced by the extruder may include rod-shaped, sheet-like, circular or the like depending on the shape of the processed die, and it may be re-molded by combining film molding, sheet molding, blow molding,

Hereinafter, a specific embodiment of the present invention will be described.

Example  One

To the first stirred tank reactor (size: 12 L) of the self-made PBS polymerization pilot lot equipment, 3,542 g of 2,973 g of 1,4-butanediol (BASF, 99.5%) and bio-derived succinic acid (Sigma-Aldrich, 9.59% The esterification reaction proceeded while mixing in a nitrogen stream. The reaction was carried out at a reaction temperature of 200 ° C for 2 hours at a stirring speed of 200 rpm until water of the theoretical value was discharged to obtain an oligomer having a number average molecular weight of 1,900 to 2,000. The oligomer was then transferred to a second reactor to proceed with the condensation polymerization. 5 g of tetraisopropyl titanate as a catalyst and 1.4 g of triethyl phosphate as a stabilizer were added and the polycondensation reaction of the oligomer was carried out for 3 hours while maintaining a reduced pressure of 0.5 torr or less at a stirring rate of 100 rpm at a temperature of 250 캜 , And the end point of the reaction was determined by observing the torque value of the agitator, thereby obtaining the final polymerized product having the target molecular weight level. The final polymerizate had a number average molecular weight of 40,000 to 60,000 at a torque value of 13.4 Nm.

1 part by weight of SONGNOX ^占 1010 as a phenolic stabilizer and 1 part by weight of talc (KCM 6300) as a nucleating agent were added to 100 parts by weight of PBS resin which was the polymerized biodegradable polyester, to prepare a composition for foaming.

Using the above-described foamable composition as a raw material, the feed side barrel temperature was 160 占 폚, the discharge side nozzle die temperature was 160 占 폚 using an extruder (Haake extrusion molding machine, screw diameter of 19.05 mm (3/4?), L / D ratio = 33: 150 ° C, a physical foaming agent CO _{2 of} 0.1 ml / min, and a discharge speed of 120 rpm.

Example  2

A foam was molded in the same manner as in Example 1, except that the polymer discharged at a torque value of 19.3 Nm and a number average molecular weight of 50,000 to 70,000 was used in Example 1.

Example  3

A foam was molded in the same manner as in Example 1 except that the polymerized material discharged at a torque value of 25 Nm and a number average molecular weight of 80,000 to 100,000 was used in Example 1, and the molded foam was shown in Fig.

Test Example

The physical properties, foamability, moldability and foam density of the foamy polymer prepared according to Examples and Comparative Examples were measured by the following methods, and the results are shown in Table 1 below.

(1) Molecular weight

The prepared PBS polymer was pretreated with chloroform at a concentration of 0.01 g / ml, and then the weight average molecular weight (Mw), number average molecular weight (Mn) and polydispersity (Mn) were measured by gel permeation chromatography (GPC-Waters 2690 model HPLC / RI Detector) (PDI) were measured. At this time, the flow rate was measured at 35 占 폚 at a flow rate of 1.0 ml / min.

(2) Intrinsic viscosity (IV)

The prepared PBS polymer was dissolved in a mixed solvent of phenol and tetrachloroethane at a molar ratio of 6: 4 at a concentration of 0.2 g / dl and measured with a Ubbelohde capillary viscometer.

(3) Melt index

And measured under a load of 2.16 kg at 190 캜 according to ASTM D1238.

(4) Foaming

After the foams foamed in the extruder were aged, the shape of the foam and the uniformity of the size of the bubbles were visually observed to show "○" (the surface was uniform and not rough), "Δ" (the surface was not uniform but rough ) And "X" (surface unevenness and roughness due to papermaking).

(5) Moldability

The injection molding was carried out in a cup shape using an injection molding apparatus, and the molded article was observed with the naked eye to obtain "?" (The surface was uniform and the gel was not visible), "?"Quot; X "(surface uneven and many gels are seen).

(6) Foam density

The density of the foams was calculated by dividing the mass of the foams by volume when the volume of water apparently increased when the foams were immersed in water.

Referring to Table 1, in the case of the foam prepared using the biodegradable polyester resin composition for foaming having a specific molecular weight, polydispersity index, melt index and intrinsic viscosity properties according to the present invention, a foam density of 0.8 g / When a biodegradable polyester resin composition for foaming having more preferable physical properties such as molecular weight, polydispersity index, melt index and intrinsic viscosity is used, not only the expansion ratio is remarkably increased but also the processability such as foamability and moldability It can be confirmed that excellent performance can be achieved.

The preferred embodiments of the present invention have been described in detail above. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing detailed description, and all changes or modifications derived from the meaning, range, and equivalence of the claims are included in the scope of the present invention Should be interpreted.

Claims (14)

Preparing an oligomer by esterifying a composition comprising an aliphatic dicarboxylic acid and an aliphatic diol at a molar ratio of 1: 1 to 1: 2 at 180 to 220 ° C for 1 to 5 hours;
0.0001 to 0.01 mole of the titanium-based catalyst based on 1 mole of the aliphatic dicarboxylic acid and 0.1 to 1 mole of the phosphorus-based thermal stabilizer based on 1 mole of the titanium-based catalyst. The oligomer is reacted at 230 to 270 ° C for 1 to 5 hours at 2 torr To produce a polyester resin; And
Adding a foaming agent to the polyester resin, melt mixing and extruding the foaming agent;
, ≪ / RTI &
The polyester resin has a weight average molecular weight (Mw) of 170,000 to 210,000, a number average molecular weight (Mn) of 70,000 to 110,000, a polydispersity index (PDI) of 1.7 to 2.2, a melt index (190 DEG C, To 30 g / 10 min and an intrinsic viscosity of 1 to 1.8 dl / g. The method according to claim 1,
Wherein the esterification reaction is a non-catalytic thermal esterification reaction. The method according to claim 1,
The aliphatic dicarboxylic acid may be selected from the group consisting of malonic acid, succinic acid, maleic acid, glutaric acid, adipic acid, pimelic acid, Wherein the polyester is at least one member selected from the group consisting of a suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, anhydrides or derivatives thereof, Method of manufacturing foamed foams. The method according to claim 1,
Wherein the aliphatic diol is selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, 1,4-butanediol, neopentyl glycol, 1,2- 2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, tetramethylcyclobutanediol, 1,6-hexanediol and 1,10-decanediol. Based on the total weight of the polyester-based foam. The method according to claim 1,
Wherein the titanium-based catalyst is at least one selected from the group consisting of tetraisopropyl titanate, tetrabutoxy titanate, tetrabutyl titanate, tetraethylene titanate, tetrastearyl titanate, and titanium acetoacetate. Ester type foam. The method according to claim 1,
Wherein the phosphorus thermal stabilizer is at least one selected from the group consisting of monomethyl phosphate, trimethyl phosphate, triethyl phosphate and triphenyl phosphate. The method according to claim 1,
Wherein the polycondensation is terminated when the viscosity of the reactant is 10 to 30 Nm based on the torque value. delete The method according to claim 1,
The blowing agent is a chemical blowing agent or a physical blowing agent, wherein the chemical foaming agent is sodium bicarbonate (NaHCO _3), ammonium carbonate _{((NH 4) 2 CO 3} ), ammonium bicarbonate (NH ₄ HCO _3), ammonium nitrite (NH ₄ NO ₂₎ , Sodium borohydride, azodicarboxylic acid amide (ADCA), azobisisobutyronitrile (AIBN), oxybis (benzene sulfonyl hydrazide) (OBSH), dinitropenta Selected from the group consisting of dinitro pentamethylene tetramine (DPT), p-toluene sulfonyl hydrazide (TSH), and p-toluene sulfonyl semicarbazide (PTSS) Wherein the physical foaming agent is at least one selected from the group consisting of aliphatic hydrocarbons, cyclobutanes, cyclopentane, cyclohexane, halogenated hydrocarbons, carbon dioxide, air, nitrogen, steam, methane and ethylene. A method for producing a polyester-based foam. The method according to claim 1,
Wherein the stabilizer and the nucleating agent are mixed with the polyester resin. 11. The method of claim 10,
Wherein the stabilizer is at least one selected from the group consisting of a phenolic stabilizer, an amine stabilizer, a phosphorus stabilizer, and a sulfur stabilizer. 11. The method of claim 10,
Wherein the nucleating agent is at least one selected from the group consisting of talc, silica, kaolin and clay as an inorganic nucleating agent. 11. The method of claim 10,
Wherein 0.1 to 30 parts by weight of the foaming agent, 0.00001 to 0.001 part by weight of the stabilizer, and 0.1 to 5 parts by weight of the nucleating agent are mixed with 100 parts by weight of the polyester resin. The method according to claim 1,
Wherein the extrusion is performed at a temperature of an extruder of 125 to 160 ° C and a die of a temperature of 115 to 135 ° C.

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