TWI465510B - Modifier for polyester resin and manufacturing method thereof - Google Patents

Description

Polyester resin modifier and method of producing the same

The present invention relates to a modifier for a polyester resin and a method for producing the same, and, in particular, to a modifier for improving the processability, hydrolysis resistance and thermal stability of a polyester resin and a method for producing the same.

Nowadays, various high molecular polymers using petroleum as raw materials are widely used in daily life, such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, etc., but the above materials are difficult to recycle, and the polymer structure is stable in a natural environment. Decomposition, and depends on the shortcomings of petrochemical raw materials. Therefore, in the context of rising awareness of environmental protection and rising oil prices, petrochemicals have turned to the development of high-molecular polymers that use plants as raw materials and can decompose themselves in the natural environment, such as fermentation of corn starch to obtain lactic acid and then polymerization. Polylactic acid (PLA) prepared by the reaction.

Polylactic acid is a relatively degradable polymeric material currently used in research, but due to its inherent relationship with aliphatic polyester structure, there will be serious hydrolysis problems during high-temperature melt processing, resulting in a decrease in molecular weight of polylactic acid, resulting in overall material. Physical properties are reduced. In addition, since the crystallization rate of polylactic acid itself is slow, the efficiency of molding processing needs to be improved, and the thermal stability of the molded product needs to be improved. If the physical properties of polylactic acid can be effectively preserved, this will solve the problem that polylactic acid cannot be recycled and reused. Therefore, how to maintain the physical properties of polylactic acid materials to resist hydrolysis of processing The problem, and how to induce an increase in the rate of crystallization and increase its mechanical strength are all important issues.

In order to solve the above problems, in the processing of the polylactic acid resin, a suitable modifier is often used at the same time to improve the processability, hydrolysis resistance and/or thermal stability, for example, the invention patent of Chinese Patent Publication No. 101302284 discloses a A method for preparing high molecular weight high-performance polylactic acid, which utilizes a bifunctional blocked isocyanate as a chain extender for melt-extruding polylactic acid, which can improve the toughness, hydrolysis resistance and thermal stability of the product, but still There are the following disadvantages: (1) This modification method is only applicable to the melt extrusion processing, and must be matched with the forward alignment of the extrusion processing, so that the polylactic acid can be arranged and crystallized, and is not suitable for other molding processing processes; and (2) use Although the blocked isocyanate is relatively stable, the isocyanate is still suspected of cracking to produce toxic substances during the high temperature melting and extruding process.

Further, PCT Publication No. 2011049714 discloses a heat-resistant polylactic acid resin which utilizes a commercially available styrene maleic-anhydride copolymer as one of the components and uses an epoxy group. As a chain extender, an epoxy functional styrene-acrylate oligomer can be processed by melt-blending to improve the heat resistance of the product. However, this method still has the following problems: (1) need to add a two-component modifier; and (2) the ratio of the modifier to the product composition needs to be more than 7 wt% to achieve the above physical properties, and the product is crystallized. Rate and molding efficiency Some are not discussed.

In addition, the invention of the Republic of China Publication No. I252863 discloses a resin composition and a method for producing a resin molded body, which mainly comprises a compound containing a carbodiimide group as a hydrolysis inhibitor and a ring having a condensed azo structure. The compound acts as a crystal nucleating agent, thereby effectively increasing the crystallization rate of the product, but the resin composition still has room for improvement in molding processing efficiency.

According to the above-mentioned prior art, generally, in the case of modifying a polylactic acid resin or other polyester resin, a specific modifier is added for a certain functional requirement (such as hydrolysis resistance, heat resistance, crystallinity, etc.), so In the processing, a variety of formulations are often used for compound addition, and the total amount of modifiers is usually high (>5 wt%), which will increase the control complexity of the reforming process and increase the quality of the reforming process. Material costs and affect other physical and chemical properties inherent in the resin itself.

Therefore, it is still necessary to provide a modifier for a polyester resin and a method for producing the same to solve the problems of the conventional technology.

The main object of the present invention is to provide a polyester resin modifier and a method for producing the same, which are obtained by copolymerizing at least a nucleus segment and a chain extension segment to form a chain copolymer as a modifier, thereby using a chain copolymer. The nucleating agent and the chain extender can be simultaneously provided, and the addition amount of the group copolymer to the polyester resin is only 0.5 to 4:100, which can effectively increase the crystallization rate of the polyester resin, so it is indeed Effectively improve polyester at the same time Processability, hydrolysis resistance and thermal stability of the resin.

A secondary object of the present invention is to provide a polyester resin modifier and a method for producing the same, wherein a compatible segment can be further selected between a nucleus segment and a chain extension segment, thereby further shortening the chain The reaction time in which the copolymer and the polyester resin are melt-blended with each other to relatively improve the molding processing efficiency of the polyester resin.

Another object of the present invention is to provide a polyester resin modifier and a method for producing the same, which are obtained by synthesizing polystyrene (PS-SH) having a thiol functional group at the end by an anionic polymerization method at room temperature. The macro-starting agent of the chain copolymer can improve the general anion polymerization acrylic monomer to be carried out at a low temperature (-78 ° C), thereby simplifying the process of the modifier and reducing the manufacturing. cost.

In order to achieve the above object, the present invention provides a modifier for a polyester resin which is a chain copolymer having the following formula (I): A segment - C segment - B segment ... ( I)

Wherein the A segment is a nucleation segment formed by polymerizing a styrene monomer selected from the group consisting of styrene and alpha -methylstyrene. M-methylstyrene, o-methylstyrene, p-methylstyrene, o-ethylstyrene, p- P-ethylstyrene or p-butylstyrene; the B segment is composed of a glycidyl methacrylate (GMA) monomer or an epoxy group ( Epoxy) a chain extended segment of a monomer; and the C segment is a compatible segment formed by polymerizing a methyl methacrylate (MMA) monomer; and wherein the A segment: C segment: The molar ratio of the B segment is 1:0.5~4:0.5~5.

In one embodiment of the present invention, the copolymerized copolymer is a polystyrene segment-polymethyl methacrylate segment-poly(methacrylic acid) glycidyl ester segment (PS-b-PMMA-b- PGMA).

Further, the present invention provides another polyester resin modifier which is a chain copolymer having the following formula (II): A segment - B segment ... (II)

Wherein the A segment is a nucleation segment formed by polymerizing a styrene monomer selected from the group consisting of styrene, α -methylstyrene, m-methylstyrene, and o-methyl. Styrene, p-methylstyrene, o-ethylstyrene, p-ethylstyrene or p-tert-butylstyrene; and the B segment is made from glycidyl methacrylate (GMA) a chain extended segment in which a monomer or an epoxy monomer is polymerized; and wherein the A segment: the B segment has a molar ratio of 1:0.5 to 5.

In one embodiment of the invention, the chain copolymer is a polystyrene segment - polyglycidyl methacrylate segment (PS-b-PGMA).

In one embodiment of the invention, the number average molecular weight (Mn) of the copolymerized chain is between 6,000 and 40,000; and the epoxy equivalent of the copolymerized copolymer is between 50 and 500.

In an embodiment of the invention, the copolymerized copolymer is melt blended In the polyester resin, the polyester resin is selected from the group consisting of polylactic acid (PLA), polyethylene terephthalate (PET) or polybutylene terephthalate (PBT).

In another aspect, the present invention provides a method of producing a polyester resin comprising the steps of: heating and melting at least one polyester resin and stirring; and blending a modifier into the molten polyester resin, wherein The modifier is a chain copolymer having the above formula (I) or (II), and the weight ratio of the group copolymer blended to the polyester resin is from 0.5 to 4:100.

In one embodiment of the present invention, the temperature at which the polyester resin is heated and melted is, for example, between 155 and 280 ° C; and the rotation speed of the polyester resin is, for example, between 50 and 60 rpm, but not Limited to this.

In one embodiment of the present invention, the group copolymer having the formula (I) is synthesized in advance by a method for producing a modifier comprising the following steps: using an anionic polymerization A polystyrene (PS-SH) having a thiol functional group at the end is synthesized as a giant initiator; a giant initiator is mixed with caprolactam to react to form a two-component initiator; mixing the two components starts And a methyl methacrylate (MMA) monomer, polymerized to form an intermediate product (PS-b-PMMA); and the intermediate product is mixed with a glycidyl methacrylate (GMA) monomer to polymerize The chain copolymer (PS-b-PMMA-b-PGMA).

In an embodiment of the present invention, the anionic polymerization method comprises the steps of: mixing and reacting a styrene monomer with an organic alkali metal compound; and further adding ethylene sulfide to the mixture to carry out the reaction. To obtain polystyrene (PS-SH) having a thiol functional group at the end.

In one embodiment of the invention, the organic alkali metal compound is n-butyllithium (n-BuLi).

The above and other objects, features and advantages of the present invention will become more <RTIgt; Furthermore, the directional terms mentioned in the present invention, such as "upper", "lower", "before", "after", "left", "right", "inside", "outside" or "side", etc. Just refer to the direction of the additional schema. Therefore, the directional terminology used is for the purpose of illustration and understanding of the invention.

The invention is mainly used for providing a modifier of a polyester resin, a method for producing a polyester resin, and a method for producing a modifier for a polyester resin, wherein the modifier is mainly used for improving the processability of a polyester resin. , hydrolysis resistance and thermal stability, and increase the crystallization rate of the polyester resin, wherein the modifier is a block copolymer (also known as block copolymer), which is melt blended with polyester Resin, this The polyester resin may be selected from polylactic acid (PLA), polyethylene terephthalate (PET) or polybutylene terephthalate (PBT), and preferably refers to a polylactic acid resin.

In one embodiment of the present invention, the copolymerized chain copolymer has the following formula (I): A segment - C segment - B segment ... (I)

Wherein the A segment is a segment formed by polymerizing a styrene monomer selected from the group consisting of styrene, alpha -methylstyrene, and m-methyl. M-methylstyrene, o-methylstyrene, p-methylstyrene, o-ethylstyrene, p-ethylstyrene (p-ethylstyrene) or p-butylstyrene. The A segment is used as a nucleation segment, which mainly provides a segment which is incompatible with the polyester resin, thereby inducing crystallization of the polyester resin as a growth nucleus to enhance the heat of the polyester resin. Stability.

Further, the B segment is a segment obtained by polymerizing a glycidyl methacrylate (GMA) monomer or an epoxy monomer. The B segment is used as a chain extended segment, which mainly provides an epoxy functional group capable of reacting with an OH or COOH functional group on the polyester resin to effectively increase the molecular weight after copolymerization, and further It can improve the hydrolysis problem after the modification of polyester resin.

In addition, the C segment is a segment formed by polymerizing a methyl methacrylate (MMA) monomer; the C segment is Used as a compatible segment, which mainly improves the reaction rate when copolymerizing with a polyester resin to shorten the processing time required for melt blending.

In this embodiment, the A chain segment: the C segment: the B chain segment has a molar ratio of 1:0.5 to 4:0.5 to 5, wherein the weight portion of the C segment is, for example, 0.5, 1, 1.5. 2, 2.5, 3, 3.5 or 4; and the weight portion of the B segment is, for example, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5 or 5, but is not limited thereto.

Furthermore, the number average molecular weight (Mn) of the copolymerized chain is between 6,000 and 40,000, for example, 6000, 8000, 10000, 12000, 15000, 18000, 20000, 25000, 28000, 30,000, 35000, 38000 or 40000, but not limited to this. And the B segment of the copolymer chain copolymer has an epoxy functional group having a total epoxy equivalent of between 50 and 500, for example, 50, 100, 150, 200, 250, 300, 350 , 400, 450 or 500, but is not limited to this. The copolymer chain copolymer is, for example, a polystyrene segment-polymethyl methacrylate segment-poly(methacrylic acid epoxidized propyl ester) segment (PS-b-PMMA-b-PGMA).

In another embodiment of the present invention, the present invention may also provide another polyester resin modifier which is a chain copolymer having the following formula (II): A segment-B segment... ...(II)

Wherein the A segment is a segment obtained by polymerizing the above styrene monomer; and the B segment is a chain obtained by polymerizing a glycidyl methacrylate monomer (GMA) monomer or an epoxy monomer. Segment; and the A segment: the molar ratio of the B segment is 1:0.5-5.

In this embodiment, the number average molecular weight (Mn) of the chain copolymer is also between 6,000 and 40,000; and the epoxy equivalent of the copolymer is also between 50 and 500. The copolymerized chain copolymer is also melt blended in a polyester resin selected from the group consisting of polylactic acid (PLA), polyethylene terephthalate (PET) or polybutylene terephthalate (PBT). ). The copolymerized chain copolymer is, for example, a polystyrene segment-polyacrylic acid glycidyl ester segment (PS-b-PGMA).

The present invention will be hereinafter referred to as a chain copolymer "polystyrene segment - polymethyl methacrylate segment - polymethacrylic acid glycidyl ester segment (PS-b-PMMA-b-PGMA, hereinafter referred to as For example, PSMG) is used as a modifier, and the pre-synthesis step and the upgrading step in the modification of the polyester resin are described in detail.

First, in the present invention, before the polyester resin is modified by the modifier, it is necessary to pre-synthesize the copolymer chain copolymer as the modifier for standby, wherein the pre-synthesis step (manufacturing step) of the copolymer copolymer is mainly Including: (S01), synthesizing polystyrene (PS-SH) having a thiol functional group at the end as a giant initiator by an anionic polymerization method; (S02), mixing a giant initiator with caprolactam (CPL) a reaction to form a two-component initiator; (S03), mixing the two-component initiator with methyl methacrylate (MMA) monomer to polymerize to form an intermediate product (PS-b-PMMA); (S04), mixing the intermediate product with glycidyl methacrylate The (GMA) monomer is polymerized to form the chain copolymer (PS-b-PMMA-b-PGMA).

In more detail, in the step (S01) of an embodiment of the present invention, the vacuum reaction bottle is first taken for vacuum replacement of nitrogen three times, and 50 ml of toluene solvent is transferred into the reaction bottle by nitrogen, and styrene is added successively. 5 ml of monomer and traces of tetrahydrofuran (THF) 1 ml, followed by the addition of an organic alkali metal compound initiator, such as 1.6 M n-butyllithium (n-BuLi) 1.136 ml, mixed by stirring at room temperature with a magnet. Reaction for 1 hour. Next, 0.13 ml of ethylene sulfide was further added to the above mixture, and the reaction was carried out at room temperature for 30 minutes, after which methanol was injected to terminate the reaction. The product obtained by the reaction was added to a large amount of distilled water and stirred for 1 hour. The upper layer solution was allowed to stand by a separating funnel, and the action was repeated three times to ensure that the salt formed by the reaction was removed, and then slowly dropped into methanol to precipitate, and placed at 60 ° C. A vacuum oven for 24 hours gave a white product, a polystyrene (PS-SH) with a thiol functional group at the end, which was used as a macroinitiator. The reaction formula of this step (S01) is as follows:

Where n is a positive integer between 20 and 100.

Next, in the steps (S02) to (S04) of the present embodiment, PS-SH and caprolactam were first placed in a reaction flask, followed by vacuum replacement of nitrogen for 3 times, followed by vacuuming for 1 hour, and injection. The toluene solvent was stirred at a reaction temperature of 85 ° C for 1 hour to carry out a reaction to form a two-component initiator. Next, an appropriate amount of methyl methacrylate monomer (MMA) was poured into the two-component initiator, stirred and mixed, and reacted at a reaction temperature of 85 ° C for 12 hours to obtain an intermediate product (PS-b-PMMA) by polymerization. Then, the temperature was lowered to 75 ° C, and an appropriate amount of methacrylic ester propylene oxide (GMA) monomer was injected, stirred and mixed, and reacted at a reaction temperature of 75 ° C for 12 hours to obtain a copolymer of the copolymer chain (PS). The product of -b-PMMA-b-PGMA), the product was slowly dropped into methanol and precipitated, placed in a vacuum oven at 50 ° C for 24 hours, dissolved in cyclohexane to remove unreacted PS-SH, and then acetonitrile was used. The acetonitrile was dissolved, and the undissolved PS-b-PMMA was centrifuged out by a centrifuge. The solution was partially removed by a rotary concentrator and placed in a vacuum oven at 50 ° C for 24 hours to obtain a purified product (PS). -b-PMMA-b-PGMA). The reaction formula of this step (S02) to (S04) is as follows:

Where n is a positive integer between 10 and 400, and m is a positive integer between 10 and 500.

The above-mentioned pre-synthesized copolymer chain copolymer (PS-b-PMMA-b-PGMA) has the following formula (III):

Wherein n is a positive integer between 20 and 100, m is a positive integer between 10 and 400, and p is a positive integer between 10 and 500. .

Referring to Table 1 and Figure 1, the PS-SH and PS-b-PMMA-b-PGMA (PSMG 1, 2, 3) obtained in the above steps (S01) and (S04) are respectively colloidal. The number average molecular weight (Mn), weight average molecular weight (Mw), polydispersity index (PDI, Mw/Mn), and molar ratio were identified by permeation chromatography (GPC) and mass spectrometry (1H NMR) analysis. Epoxy equivalents were combined and the results of the analysis were summarized in Table 1. Further, Figure 1 reveals a plot of the molecular weight of PS-SH and PSMG as a function of time.

After the pre-synthesis of the copolymerized chain copolymer, the polyester resin may be modified, and the manufacturing (modification) method comprises the steps of: (S11), heating and melting at least one polyester resin; and (S12) Adding a modifier to the molten polyester resin, wherein the modifier is a chain copolymer having the above formula (I) or (II), and the copolymer of the chain copolymer The weight ratio to the polyester resin is from 0.5 to 4:100.

More specifically, in an embodiment of the invention, the chain copolymer is, for example, PS-b-PMMA-b-PGMA, and the polyester resin is, for example, a polylactic acid resin. The part by weight of the copolymerized copolymer blended into the polyester resin is, for example, 0.5, 1, 1.5, 2, 2.5, 3, 3.5 or 4, but is not limited thereto. In the process of upgrading, the polylactic acid is firstly dried and pretreated, and then the polylactic acid is melt-stirred at a different temperature (155 to 200 ° C) and a fixed rotation speed of 50 to 60 rpm by a plastic spectrometer, and then the above-mentioned dough is added. The chain copolymer 1 wt% (actual blending ratio of 1:100) was used as a modifier, and different melt mixing reaction times were taken for the following comparison.

The above modified polylactic acid resin is subjected to different physical properties. Analysis of comparison. GPC analysis was used to compare the molecular weight difference before and after polylactic acid modification, and the improvement of hydrolysis resistance was discussed. The difference of crystallization rate before and after polylactic acid modification was analyzed by differential scanning calorimeter (DSC). Improve; and use thermogravimetric analyzer (TGA) to analyze the difference of thermal stability before and after polylactic acid modification, and explore the improvement of thermal stability of modifier.

Please refer to Table 2 and Figure 2 below. Table 2 shows the GPC molecular weight analysis of various products with different melt-mixing reaction time at 155 ° C and 60 rpm after adding 1 wt% of PSMG 3 modifier to polylactic acid resin. As a result, and Fig. 2 is a graph showing the change in molecular weight of polylactic acid resin (PLA, with a single peak) and modified polylactic acid resin (PLA + PSMG melt blended at 155 ° C for 14 minutes, with double peak) as a function of time. It can be seen from Table 2 that the molecular weight of the polylactic acid resin can be effectively increased after adding the modifier PSMG 3 of Table 1, and the weight average molecular weight of the polylactic acid can be increased from the original 97600 g/mole to 316600 g as the reaction time is elongated. /mole, wherein the increase in molecular weight can be regarded as contributing to an increase in the overall physical properties of the polylactic acid resin, and therefore the modifier PSMG does have a function as a chain extender, that is, it can improve the problem of high temperature hydrolysis of the polylactic acid resin.

Please refer to Table 3 below, which shows the results of GPC molecular weight analysis of various products of different melt-blending reaction time at 200 ° C and 60 rpm after adding 1 wt% of PSMG 3 modifier to polylactic acid resin. Similarly, when the polylactic acid resin of Table 3 is added to the modifier PSMG 3 of Table 1, the molecular weight of the polylactic acid resin can be effectively increased, and as the reaction time is elongated, the weight average molecular weight of the polylactic acid can be obtained from the original 97600. The g/mole is raised to 296500 g/mole. Furthermore, compared to the melt blending conditions of Table 2 (155 ° C and 60 rpm), Table 3 can shorten the reaction time (from 14 minutes to 8 minutes) after increasing the melt blending temperature to 200 ° C. It is used in general single or twin screw melt processing processes (extrusion molding and injection molding) and reduces processing time. Although 8 minutes is still too long for general processing time, the high shear force through the twin-screw extruder can be completed in a short time at 200 °C. In general, the spectrometer (~50 rpm, laboratory test) and the extruder (~500 rpm, actual production) have different rotational speeds, so the present invention is not limited to the above-mentioned 50-60 rpm rotational speed condition, and the present invention has been performed by a twin-screw extruder. In the experiment, it was found that the overall processing time was less than two minutes, that is, the above molecular weight rise and the effect of inducing crystallization.

Referring to Table 4 below, the thermal analysis results of the modified polylactic acid resin are disclosed. From the DSC analysis results, the glass transition temperature (Tg) and the melting point (Tm) of the modified polylactic acid resin are compared with the original polylactic acid. There was no significant change in the resin. However, when the reaction time was extended from 10 minutes to more than 12 minutes, the modified glass-transfer temperature (Tg) could not be observed in the modified polylactic acid resin, and the weight average molecular weight was more than 300,000 g/mole. Therefore, the glass transition temperature is not obvious for the increase of crystallinity. Further, the Td ⁵ shown in Table 4 is a temperature at which the TGA analysis sample is thermally cracked by 5 wt%, and it is understood that the 5 wt% thermal cracking temperature of the polylactic acid resin of the unmodified polylactic acid is 313 ° C, and the polylactic acid resin is added. After the 1 wt% modifier PSMG 3, the Td ⁵ to 331 ° C can be effectively improved, which can effectively improve the thermal stability of the polylactic acid resin.

Please also refer to Figures 3A and 3B, which are polylactic acid resins. (PLA) and various modified polylactic acid resins (PLA + PSMG 3 155 ° C - 10, 12, 14 mins) DSC cooling curve and temperature rise graph, from the cooling curve of Figure 3A, the unmodified polylactic acid resin The crystallinity is poor, so the cold crystallization phenomenon is not obvious; after adding 1wt% modifier PSMG 3, when the reaction time of the modified polylactic acid resin is extended to more than 12 minutes, there is a significant cooling peak of cold crystallization (such as Tc) shown in Table 4, and in the temperature rise curve of Fig. 3B, there is no recrystallization phenomenon, which indirectly indicates that the modified polylactic acid has been completely cooled and crystallized at the time of cooling. It can be seen from the above that the modifier PSMG can effectively enhance the crystallization characteristics of the polylactic acid resin and has the function of a nucleating agent, thereby improving the processability of the polylactic acid resin.

Next, please refer to the following Table 5, which is the GPC molecular weight analysis, DSC and TGA analysis results of the product after processing at different temperatures and reaction time after adding 1 wt% of the modifier PSMG 3 to the polylactic acid resin. It can be seen from Table 5 that the addition of 1 wt% of the modifier PSMG 3 to the polylactic acid resin can effectively improve the hydrolysis resistance, crystallinity and thermal stability of the polylactic acid resin by using different reaction temperatures and time processing, and By increasing the temperature (from 180 ° C to 250 ° C), the reaction time can be relatively reduced (from 8 minutes to 2 minutes), indicating that it can be applied to the general single or twin screw melt processing process (extrusion molding and injection) Molding), that is, it can effectively improve the above-mentioned processing properties of the polylactic acid resin in the melt-mixing process.

As described above, the present invention is to copolymerize at least a chain segment (chain nucleus segment) and a B segment (chain extension segment) to form a chain copolymer as a modifier, whereby the group copolymer can be simultaneously provided. The role of the nucleating agent and the chain extender, and the addition amount of the group copolymer to the polyester resin is only 0.5 to 4:100, which can effectively increase the crystallization rate of the polyester resin, so it is effective at the same time. Improves the processability, hydrolysis resistance and thermal stability of polyester resins. In particular, the present invention further selects a C segment (compatibility segment) between the A segment (nucleation segment) and the B segment (chain extension segment), thereby further shortening the The reaction time of the melt copolymerization of the copolymerized copolymer with the polyester resin is relatively increased to improve the molding processing efficiency of the polyester resin. Furthermore, the present invention can synthesize a polystyrene (PS-SH) having a thiol functional group at the end by an anionic polymerization method as a giant initiator of the group copolymer, thereby improving the general anionic polymerization. The disadvantage that the acrylic monomer needs to be carried out at a low temperature (-78 ° C) can relatively simplify the process of the modifier and reduce the manufacturing cost.

Although the invention has been disclosed in the preferred embodiments, it is not intended to be limiting In the present invention, those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention, and the scope of the present invention is defined by the scope of the appended claims. .

Fig. 1 is a graph showing the change in molecular weight of a macroinitiator (PS-SH) and agglomerate copolymer (PSMG) according to a preferred embodiment of the present invention over time.

Fig. 2 is a graph showing the change in molecular weight of polylactic acid resin (PLA, with a single peak) and modified polylactic acid resin (PLA + PSMG 155 ° C - 14 mins, with double peak) according to a preferred embodiment of the present invention.

3A and 3B are graphs showing DSC cooling curves and temperature rise curves of polylactic acid resin (PLA) and various modified polylactic acid resins (PLA+PSMG 3 155 ° C - 10, 12, 14 mins) according to a preferred embodiment of the present invention.

Claims (13)

A modifier of a polyester resin which is a chain copolymer having the following formula (I): A segment - C segment - B segment ........................... I) wherein the A segment is a nucleation segment obtained by polymerizing an styrene monomer by an anionic polymerization method, and the styrene monomer is selected from the group consisting of styrene, α-methylstyrene, and m-methylbenzene. Ethylene, o-methyl styrene, p-methyl styrene, o-ethyl styrene, p-ethyl styrene or p-tert-butyl styrene; the B segment is composed of methacrylic acid epoxy a chain extended segment obtained by polymerizing a propyl ester monomer or an epoxy monomer; and the C segment is a compatible segment formed by polymerizing a methyl methacrylate monomer; and wherein the A segment is: C segment: The molar ratio of the B segment is 1:0.5~4:0.5~5. The modifier of the polyester resin according to claim 1, wherein the copolymer of the group is a polystyrene segment-polymethyl methacrylate segment-polymethacrylate propylene glycol chain Segment (PS-b-PMMA-b-PGMA). A modifier of a polyester resin which is a chain copolymer having the following formula (II): A segment-B segment............................................. Wherein the A segment is a nucleation segment obtained by polymerizing an styrene monomer by an anionic polymerization method, the styrene monomer being selected from the group consisting of styrene, Α-methylstyrene, m-methylstyrene, o-methylstyrene, p-methylstyrene, o-ethylstyrene, p-ethylstyrene or p-tert-butylstyrene And the B segment is a chain extended segment obtained by polymerizing a glycidyl methacrylate monomer or an epoxy monomer; and wherein the A segment: B segment has a molar ratio of 1:0.5 ~5. The modifier of the polyester resin according to claim 3, wherein the copolymerized copolymer is a polystyrene segment-polyacrylic acid glycidyl ester segment (PS-b-PGMA). The modifier of the polyester resin according to claim 1 or 3, wherein the number average molecular weight of the chain copolymer is between 6,000 and 40,000; and the epoxy equivalent of the copolymer Between 50 and 500. The modifier of the polyester resin according to claim 1 or 3, wherein the copolymerized copolymer is melt blended in a polyester resin selected from the group consisting of polylactic acid and polyterephthalic acid. Ethylene glycol or polybutylene terephthalate. A method for producing a polyester resin, comprising the steps of: heating and melting at least one polyester resin and stirring; and blending a modifier into the molten polyester resin, wherein the modifier is as claimed The group chain copolymer of the formula (I) or (II) described in the first or third aspect of the patent, and the weight ratio of the group chain copolymer blended into the polyester resin are from 0.5 to 4:100. The manufacturer of the polyester resin as described in claim 7 The method wherein the temperature of the polyester resin is heated and melted is between 155 and 280 °C. The method for producing a polyester resin according to claim 7, wherein the group copolymer having the formula (I) is synthesized in advance by the following steps: synthesizing a terminal having a thiol functional group by an anionic polymerization method Polystyrene (PS-SH) as a giant initiator; mixing a giant initiator with caprolactam to react to form a two-component initiator; mixing the two-component initiator with methyl methacrylate a polymerization reaction to form an intermediate product (PS-b-PMMA); and mixing the intermediate product with a glycidyl methacrylate monomer to polymerize into the copolymerized chain copolymer (PS-b-PMMA-b- PGMA). The method for producing a polyester resin according to claim 9, wherein the anionic polymerization method comprises the steps of: mixing a styrene monomer with an organic alkali metal compound and performing a reaction; and further adding a cyclohexane to carry out the reaction. To obtain polystyrene (PS-SH) having a thiol functional group at the end. A method for producing a modifier for a polyester resin according to claim 1, which comprises the step of synthesizing polystyrene (PS-SH) having a thiol functional group at the end as a giant starting by an anionic polymerization method. Mixing a giant initiator with caprolactam for reaction to form a two-component a starting agent; mixing the two-component initiator with a methyl methacrylate monomer to polymerize to form an intermediate product (PS-b-PMMA); and mixing the intermediate product with a glycidyl methacrylate monomer to Polymerization was carried out into the copolymerized chain copolymer (PS-b-PMMA-b-PGMA). The method for producing a modifier for a polyester resin according to claim 11, wherein the anionic polymerization method comprises the steps of: mixing a styrene monomer with an organic alkali metal compound and performing a reaction; and further adding an episulfide Ethane is reacted to obtain polystyrene (PS-SH) having a thiol functional group at the end. The method for producing a modifier for a polyester resin according to claim 12, wherein the organic alkali metal compound is n-butyllithium.