KR102267207B1 - Polyester resin composition and molded article using said polyester resin composition - Google Patents

Abstract

A polyester-based resin composition containing a polyester-based resin (A) and a carbodiimide compound (B) represented by the general formula (1), wherein the content of the carbodiimide compound (B) is a polyester-based resin (A) and It is a polyester resin composition of 0.1-10 weight part with respect to 100 weight part of total amounts of a carbodiimide compound (B).

Description

A polyester-based resin composition, and a molded article using the polyester-based resin composition {POLYESTER RESIN COMPOSITION AND MOLDED ARTICLE USING SAID POLYESTER RESIN COMPOSITION}

The present invention relates to a polyester-based resin composition containing a polyester-based resin and a carbodiimide compound, and to a molded article using the polyester-based resin composition.

Polyester resins are widely used in films, sheets, and the like because of their excellent transparency, mechanical strength, melt stability, solvent resistance, and recyclability, and in recent years, they are also used in the cases of home appliances and OA equipment.

However, since the polyester resin has the property of being easily hydrolyzed compared with the conventional general-purpose resin, the method of adding a carbodiimide compound for the purpose of improving hydrolysis resistance is examined.

By mixing the carbodiimide compound with the polyester resin and molding it, the carbodiimide compound captures the carboxyl groups in the polyester resin or the carboxyl groups generated by the decomposition of the ester group when kneading at high temperature, thereby suppressing the initial performance degradation of the molded product. can do. In addition, the durability of the molded article is also improved by the presence of the carbodiimide compound in the molded article.

For example, Patent Document 1 discloses a hydrolysis-resistant stabilizer for an unsaturated polyester resin, characterized in that it contains a specific aliphatic or aromatic carbodiimide compound as a main component as a hydrolysis-resistant stabilizer for an unsaturated polyester resin. .

Patent Document 2 discloses that it has a carbodiimide structure as a stabilizer against cleavage by hydrolysis of a polyester plastic, and further has a urethane structure, a urea structure, or both structures, is solid at 25°C, and has a carbodiimide structure Carbodiimides bonded to non-aromatic carbon atoms are disclosed.

Patent Document 3 discloses an organic chain containing a urethane bond and/or a urea bond without continuously bonding carbodiimide groups for the purpose of improving strength, adhesion and adhesion when used as a crosslinking agent such as a resin or a thermosetting resin. Specific polycarbodiimide compounds bound through the method are disclosed.

Patent Document 4 discloses an aliphatic polyester resin composition containing an aliphatic polyester resin, a hydrolysis inhibitor, and a non-reactive silicone for the purpose of obtaining an aliphatic polyester resin composition excellent in moisture and heat aging resistance. Among them, a technique using a carbodiimide-based compound as a hydrolysis inhibitor and an adipic acid ester as a plasticizer is disclosed.

Patent Document 5 discloses a polyester polycarbodiimide air having a chemical structure in which a polyester segment having a number average molecular weight of 5,000 to 30,000 and a polycarbodiimide segment are linked by a urethane bond for the purpose of achieving both hydrolysis resistance and bending workability. Adhesives and adhesive compositions containing them are disclosed.

Japanese Patent Application Laid-Open No. 9-249801 Japanese Patent Application Laid-Open No. 2000-256436 Japanese Patent Laid-Open No. 2002-3564 Japanese Patent Laid-Open No. 2009-256405 Japanese Patent Application Laid-Open No. 2013-75972

In the technique of Patent Document 1, hydrolysis of the polyester resin can be suppressed, but during melt-kneading and molding, the carboxy group in the polyester resin and the carbodiimide group react rapidly, resulting in an increase in viscosity or gelation. In some cases, it may be difficult to produce a stable molded product. Moreover, when an aromatic polycarbodiimide was used, since the crosslinking reaction of a polyester resin advanced, there existed a problem that the crystallization of a crystalline polyester resin was inhibited.

In the technique of Patent Document 2, solid carbodiimide can be obtained, and by adding this carbodiimide to a polyester-based plastic, the strength retention at low temperature can be improved, but hydrolysis resistance is low and storage at high temperature and high humidity There was a problem that the strength retention rate afterward was inferior.

In the technique of Patent Document 3, since the polycarbodiimide compound binds the carbodiimide group through an organic chain instead of continuously bonding the carbodiimide group, the concentration of the carbodiimide group in the molecule is lowered, and the hydrolysis inhibitory effect of the polyester resin is reduced. There were cases where it was damaged.

In the technique of Patent Document 4, the moldability can be improved by using a plasticizer, but when a general plasticizer such as phthalic acid ester is used, bleed-out from the molded product may occur depending on the added amount, and the physical properties of the molded product may be lowered or bleed. There was a problem that the environment, health problems, etc. were caused by the outdated material. Moreover, since these plasticizers do not have reactivity with a carboxy group, the hydrolysis inhibitory effect of a carbodiimide compound may be reduced, and improvement was desired.

In the technique of Patent Document 5, the objective is a coating film excellent in hydrolysis resistance and bending workability, but since the polyester-polycarbodiimide copolymer is the main component, the applicable uses are limited, and additional productivity and cost are also added. There were cases where improvement was desired.

An object of the present invention is to provide a polyester-based resin composition that is excellent in hydrolysis resistance and bleed-out resistance, which does not cause a significant increase in melt viscosity and solution viscosity, and a molded article using the polyester-based resin composition.

MEANS TO SOLVE THE PROBLEM As a result of repeating earnest examination in order to achieve the said objective, the present inventors discovered that the said subject could be solved by mix|blending a specific carbodiimide compound in a specific ratio with respect to a polyester resin, and completed this invention.

That is, the present invention provides the following polyester-based resin composition, and a molded article using the polyester-based resin composition.

[1] A polyester-based resin composition containing a polyester-based resin (A) and a carbodiimide compound (B) having a structure represented by the following general formula (1), wherein the content of the carbodiimide compound (B) The polyester resin composition which is 0.1-10 weight part with respect to 100 weight part of total amounts of this polyester-type resin (A) and a carbodiimide compound (B).

[Tue 1]

In the formula, R ¹ represents a divalent organic group having at least one aromatic group. However, -N=C=N- shall be directly bonded to the aromatic ring of ^{R 1 .} R ² represents a divalent residue of a diol compound, x represents a number of 2 or more, and y represents a number of 1 or more.

[2] The polyester-based resin composition according to the above [1], wherein the diol compound is at least one selected from polyether polyol, polyester polyol, polycarbonate polyol, and alkylenediol.

[3] The polyester resin composition according to [1] or [2], wherein the number average molecular weight of the diol compound is 100 to 40,000.

[4] The ^{polyester resin composition according to any one of [1] to [3], wherein R 1} is at least one divalent residue selected from tolylene diisocyanate, tolidine diisocyanate, and diphenylmethane diisocyanate.

[5] The polyester resin composition according to any one of [1] to [4], wherein the carbodiimide equivalent of the carbodiimide compound (B) is 200 to 1,500.

[6] The above [1] to [5] wherein the polyester-based resin (A) is at least one selected from polyethylene terephthalate, polybutylene terephthalate, polybutylene succinate, polylactic acid, and polyhydroxyalkanoic acid. The polyester-based resin composition according to any one of ].

[7] The polyester resin composition according to any one of [1] to [6], wherein the carbodiimide compound (B) is terminal-blocked with monoalcohol, monophenol, monoisocyanate, or monoamine.

[8] A molded article molded using the polyester-based resin composition according to any one of [1] to [7].

According to the present invention, it is possible to provide a polyester-based resin composition having excellent hydrolysis resistance and bleed-out resistance, which does not cause a significant increase in melt viscosity and solution viscosity, and a molded article using the polyester-based resin composition. have.

[Polyester-based resin composition]

The polyester-based resin composition of the present invention is a polyester-based resin composition containing a polyester-based resin (A) and a carbodiimide compound (B) having a structure represented by the following general formula (1), wherein the carbodiimide Content of compound (B) is 0.1-10 weight part with respect to 100 weight part of total amounts of polyester-type resin (A) and carbodiimide compound (B), It is characterized by the above-mentioned.

[Tue 2]

In the formula, R ¹ represents a divalent organic group having at least one aromatic group. However, -N=C=N- shall be directly bonded to the aromatic ring of ^{R 1 .} R ² represents a divalent residue of a diol compound, x represents a number of 2 or more, and y represents a number of 1 or more.

Although the reason why the polyester resin composition of this invention is excellent in hydrolysis resistance and bleed-out resistance and does not cause a significant increase in melt viscosity and solution viscosity is not certain, it thinks as follows.

Since the carbodiimide compound (B) contained in the polyester-based resin composition of the present invention has a residue of a diol compound between the carbodiimide segments, its compatibility with the polyester-based resin (A) is good and more uniformly Since it can be disperse|distributed in the polyester-type resin (A), it is thought that a viscosity increase was suppressed without causing a local crosslinking reaction in the composition at the time of melt-kneading. In the case of a carbodiimide compound (B), the carbodiimide group bleeds out because the carbodiimide group reacts with a carboxy group present in the polyester resin (A) or a carboxy group generated by decomposition of the polyester resin (A). However, since the carbodiimide compound (B) in which the carbodiimide group does not react also has high affinity with the polyester-based resin (A), it is considered that it is difficult to bleed out.

Moreover, it is thought that by using a specific aromatic polycarbodiimide as the polycarbodiimide, excellent hydrolysis resistance could be exhibited even at a carbodiimide group concentration lower than that of the conventional aliphatic polycarbodiimide.

<Polyester-based resin (A)>

As the polyester-based resin (A), any resin having an ester group can be used without any particular limitation.

As such a polyester-based resin (A), for example, polyethylene terephthalate (hereinafter also referred to as "PET"), polybutylene succinate (hereinafter also referred to as "PBS"), polybutylene succinate adipate ( Hereinafter also referred to as "PBSA"), polybutylene adipate terephthalate (hereinafter also referred to as "PBAT"), polybutylene terephthalate (hereinafter also referred to as "PBT"), polyethylene naphthalate, polyarylate, ethylene At least one selected from polyhydroxyalkanoic acids (hereinafter, also referred to as “PHA”) such as terephthalate-isophthalate copolymer, polylactic acid (hereinafter also referred to as “PLA”), and polybutyric acid can be used.

Among these, from the viewpoint of economy and processability, preferably at least one selected from polyethylene terephthalate, polybutylene terephthalate, polybutylene succinate, polylactic acid, and polyhydroxyalkanoic acid, more preferably polyethylene It is terephthalate.

By containing the carbodiimide compound (B) having a specific structure, the polyester resin composition of the present invention can suppress the crosslinking reaction of the polyester resin (A), and like the conventional carbodiimide compound, poly Since there is nothing inhibiting the crystallization of an ester resin, a crystalline polyester resin can also be used suitably.

The content of the polyester-based resin (A) in the polyester-based resin composition of the present invention is preferably 80 to 99.9% by weight, more preferably 85 to 99.8% by weight, still more preferably 90 to 99.7% by weight, further Preferably it is 95-99.5 weight%.

<Carbodiimide compound (B)>

The carbodiimide compound (B) used in the present invention has a structure represented by the following general formula (1).

[Tue 3]

In the formula, R ¹ represents a divalent organic group having at least one aromatic group. However, -N=C=N- shall be directly bonded to the aromatic ring of ^{R 1 .} R ² represents a divalent residue of a diol compound, x represents a number of 2 or more, and y represents a number of 1 or more.

In the carbodiimide compound (B), the content of the structure represented by the general formula (1) is preferably 50% by weight or more from the viewpoint of hydrolysis resistance, melt viscosity, and solution viscosity of the polyester-based resin composition, more Preferably it is 60 weight% or more, More preferably, it is 70 weight% or more, More preferably, it is 80 weight% or more.

In general formula (1), R<^1> is a divalent organic group which has at least 1 piece(s) of aromatic group. However, -N=C=N- shall be directly bonded to the aromatic ring of ^{R 1 .}

In the carbodiimide compound (B) used in the present invention, the carbodiimide group (-N=C=N-) is directly bonded to the aromatic ring, so that the reactivity with the carboxyl group can be increased, and lower than that of the conventional aliphatic polycarbodiimide. It is thought that the outstanding hydrolysis resistance was able to be exhibited also in the carbodiimide group density|concentration.

Examples of the divalent organic group having at least one aromatic group include a divalent residue of diisocyanate (hereinafter also referred to as “diisocyanate (a)” or “component (a)”) having at least one aromatic group, polyester From the viewpoints of hydrolysis resistance, melt viscosity, and solution viscosity of the system resin composition, it is preferably a diisocyanate having 1 or 2 aromatic groups, and more preferably an aromatic diisocyanate having 1 or 2 aromatic groups.

[diisocyanate; (a) component]

As the component (a), for example, phenylene diisocyanate, tolylene diisocyanate, tolidine diisocyanate, 1,5-naphthalene diisocyanate, diphenylmethane diisocyanate, diphenyldimethylmethane diisocyanate, diphenyl ether diisocyanate, 3 and ,3'-dimethylbiphenyl-4,4'-diisocyanate. Among these, from the viewpoint of hydrolysis resistance, melt viscosity, and solution viscosity of the polyester resin composition, preferably at least one selected from tolylene diisocyanate, tolidine diisocyanate, and diphenylmethane diisocyanate, more preferably tolylene diisocyanate.

In the general formula (1), R ² represents a divalent residue of a diol compound (hereinafter also referred to as “diol compound (b)” or “component (b)”). In addition, in this specification, a diol compound means the compound which has two hydroxyl groups in a molecule|numerator.

Since the carbodiimide compound (B) used in the present invention has a divalent residue of the diol compound between polycarbodiimide groups, it has good compatibility with the polyester-based resin (A) and is more uniformly polyester-based. Since it can be disperse|distributed in resin (A), it is thought that a viscosity increase could be suppressed without causing a local crosslinking reaction in the composition at the time of melt-kneading.

[diol compound; (b) component]

As said component (b), the high molecular compound and low molecular weight compound which have two hydroxyl groups in a molecule|numerator are mentioned.

Examples of the polymer compound having two hydroxyl groups in the molecule include polyether polyol, polyester polyol, polycarbonate polyol, silicone diol, polyolefin polyol, polyurethane polyol, and alkylene (C21-C) diol. Among these, from the viewpoint of melt viscosity and solution viscosity of the polyester resin composition, preferably at least one selected from polyether polyol, polyester polyol, polycarbonate polyol, and alkylenediol, more preferably poly At least one selected from ester polyol and polycarbonate polyol, more preferably polycarbonate polyol.

Examples of the low molecular weight compound having two hydroxyl groups in the molecule include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 2-methyl-1,3-propanediol, alkanediols such as neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, and alkylene (C7-20) diol; alkene diols such as diols having alicyclic aliphatic groups such as cyclohexanediol, cyclohexanedimethanol and hydrogenated bisphenol A, and 1,4-dihydroxy-2-butene; Diol which has aromatic rings, such as bishydroxyethoxybenzene, xylene glycol, and bis(2-hydroxyethyl) terephthalic acid, etc. are mentioned. Among these, from the viewpoint of melt viscosity and solution viscosity of the polyester resin composition, preferably alkylenediol or diol having an aromatic ring, more preferably diol having an aromatic ring, still more preferably bis(2- hydroxyethyl) terephthalic acid.

(b) The number average molecular weight of the component is preferably 100 to 40,000, more preferably 150 to 10,000, still more preferably 200 to from the viewpoint of hydrolysis resistance, melt viscosity, and solution viscosity of the polyester resin composition. It is 1,000. In addition, the number average molecular weight is measured using polystyrene as a standard substance by the gel chromatography method. However, exceptions are made for low molecular weight compounds.

In general formula (1), x represents the number 2 or more, and y represents the number 1 or more.

In the general formula (1), x is preferably 2 to 30, more preferably 2 to 25, still more preferably 2 to from the viewpoint of hydrolysis resistance, melt viscosity, and solution viscosity of the polyester-based resin composition. 20.

In general formula (1), y is from the same viewpoint, Preferably it is 1-20, More preferably, it is 1-15, More preferably, it is 1-10.

The carbodiimide compound (B) used in the present invention is obtained by sealing the remaining terminal isocyanate with a terminal blocker (hereinafter also referred to as "terminal blocker (c)" or "component (c)"), whereby a carbodiimide compound ( Since the compatibility of B) with respect to the polyester-type resin (A) and the storage stability of a polyester-type resin composition can be improved, and quality can be improved, it is preferable.

[End encapsulant; (c) component]

Monoalcohol, monophenol, monoisocyanate, monoamine etc. are mentioned as said (c) component.

As said monoalcohol, methanol, ethanol, cyclohexanol, polyethyleneglycol monomethyl ether, polypropylene glycol monomethyl ether, etc. are mentioned.

Phenol, methylphenol, dimethylphenol, naphthol etc. are mentioned as said monophenol.

Examples of the monoisocyanate include lower alkyl monoisocyanates such as methyl isocyanate, ethyl isocyanate, propyl isocyanate, n-, sec- or tert-butyl isocyanate; alicyclic aliphatic monoisocyanates such as cyclohexyl isocyanate; Aromatic monoisocyanate, such as phenyl isocyanate, tolyl isocyanate, dimethylphenyl isocyanate, and 2, 6- diisopropyl phenyl isocyanate, etc. are mentioned.

Examples of the monoamine include primary amines such as butylamine and cyclohexylamine; and secondary amines such as diethylamine, dibutylamine and dicyclohexylamine.

Among these, from the viewpoint of improving the compatibility of the carbodiimide compound (B) with the polyester resin (A) and storage stability of the polyester resin composition, preferably monoalcohol or monoisocyanate, more preferably mono isocyanates, more preferably aromatic monoisocyanates, even more preferably phenylisocyanates.

A terminal blocker (c) may be used individually by 1 type or in combination of 2 or more type.

(carbodiimide equivalent)

The carbodiimide equivalent of the carbodiimide compound (B) (the formula weight per 1 mol of the carbodiimide group) is preferably 200 to 1,500 from the viewpoint of hydrolysis resistance, melt viscosity, and solution viscosity of the polyester resin composition. , More preferably, it is 250-1,250, More preferably, it is 300-1,000.

(Content of carbodiimide compound (B))

The content of the carbodiimide compound (B) is 100 weight of the total amount of the polyester resin (A) and the carbodiimide compound (B) from the viewpoint of hydrolysis resistance, melt viscosity, and solution viscosity of the polyester resin composition It is 0.1-10 weight part with respect to a part, Preferably it is 0.2-6 weight part, More preferably, it is 0.3-4 weight part, More preferably, it is 0.5-2 weight part.

(Number average molecular weight of carbodiimide compound (B))

The number average molecular weight of the carbodiimide compound (B) is preferably 250 to 50,000, more preferably 300 to 10,000, further preferably from the viewpoint of hydrolysis resistance, melt viscosity, and solution viscosity of the polyester-based resin composition. preferably 400 to 5,000, and even more preferably 500 to 3,000. In addition, the number average molecular weight is measured using polystyrene as a standard substance by the gel chromatography method.

<Method for producing carbodiimide compound (B)>

The carbodiimide compound (B) used in the present invention can be produced according to a known method.

For example,

(i) a diisocyanate (a) and a diol compound (B) are reacted to produce a compound of isocyanate at both ends containing a urethane bond (hereinafter also referred to as “component (d)”), and then (a) component, (d) a method of carbodiimidizing and end capping the component and the end capping agent (c) in the presence of a catalyst;

(ii) carbodiimidization of diisocyanate (a) in the presence of a catalyst to obtain polycarbodiimide (hereinafter also referred to as "component (e)"), and then a diol compound (b) in component (e); and a method of adding an end-blocking agent (c), and performing a copolymerization reaction and an end-blocking reaction;

(iii) a method in which diisocyanate (a), diol compound (b), and terminal blocker (c) are subjected to a urethanation reaction, carbodiimidization reaction, and terminal block reaction in the presence of a catalyst; and the like.

Among these, it is preferable to manufacture according to the said method (i) from a viewpoint of productivity.

Specifically, the diisocyanate (a) and the diol compound (B) are mixed with the hydroxyl group of the diol compound (b) so that the isocyanate group of the diisocyanate becomes excessive, followed by a urethanation reaction, and then a terminal blocker ( c) and it is preferable to add an organophosphorus compound or an organometallic compound as a carbodiimidization catalyst, and carry out the carbodiimidization reaction in a solvent-free or inert solvent.

Specific examples of the carbodiimidization catalyst include 3-methyl-1-phenyl-2-phosphorene-1-oxide, 3-methyl-1-ethyl-2-phosphorene-1-oxide, and 1,3-dimethyl -2-phosphorene-1-oxide, 1-phenyl-2-phosphorene-1-oxide, 1-ethyl-2-phosphorene-1-oxide, 1-methyl-2-phosphorene-1- oxides and the like. Among these, 3-methyl-1-phenyl-2-phosphoene-1-oxide, which is industrially readily available, is preferable. The carbodiimidization catalyst may be used individually by 1 type or may use 2 or more types together.

The reaction temperature of the urethanation reaction of the component (a) and the component (b) can be appropriately determined depending on the raw material used, but from the viewpoint of productivity, preferably 30 to 200° C., more preferably 35 to 120° C., More preferably, it is 40-80 degreeC.

The reaction temperature of the carbodiimidization reaction is preferably 40 to 250°C, more preferably 60 to 200°C, still more preferably 80 to 150°C from the viewpoint of productivity.

From the same viewpoint, the reaction time of the carbodiimidization reaction is preferably 10 minutes to 20 hours, more preferably 1 hour to 10 hours, still more preferably 2 hours to 4 hours.

The amount of the carbodiimidization catalyst used can be appropriately determined depending on the type of catalyst to be used, but preferably 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight, based on 100 parts by weight of diisocyanate (a), More preferably, it is 0.1-3 weight part.

<Other ingredients>

Additives, such as a pigment, a filler, a leveling agent, surfactant, a dispersing agent, a ultraviolet absorber, antioxidant, a flame retardant, and a coloring agent, can be mix|blended suitably with the polyester resin composition as needed.

<Total content of polyester-based resin (A) and carbodiimide compound (B)>

The total content of the polyester-based resin (A) and the carbodiimide compound (B) in the polyester-based resin composition of the present invention is from the viewpoint of processability, hydrolysis resistance, melt viscosity, and solution viscosity of the polyester-based resin composition, Preferably it is 90-100 weight%, More preferably, it is 92-100 weight%, More preferably, it is 95-100 weight%.

<Method for producing a polyester-based resin composition>

The polyester resin composition of the present invention can be produced by, for example, blending the carbodiimide compound (B) and other components to be added as necessary with the polyester resin (A), and melt-kneading it. .

In the method for producing the polyester resin composition of the present invention, by using the carbodiimide compound (B), a significant increase in melt viscosity can be suppressed and workability at the time of melt kneading can be improved. It is thought that the productivity of a resin composition is excellent.

Melt-kneading can be performed using a well-known mixer etc. provided with a heating means. Although there is no particular limitation on the order in which each material is put into the mixer, the polyester-based resin (A) serving as the base is first added and melted, and then the carbodiimide compound (B) and other components added as needed are added. It is preferable to do

The melt-kneading time can be appropriately determined depending on the shape of the screw, rotational speed, etc., and is usually about 1 to 10 minutes. Moreover, although the temperature at the time of melt-kneading changes with the kind of polyester-type resin (A) used as a base, it is about 150-350 degreeC normally.

[Molded article using polyester-based resin composition]

The molded article of the present invention is a molded article molded using the polyester-based resin composition of the present invention.

When obtaining a molded article from the polyester-based resin composition of the present invention, it may be molded by extrusion molding, injection molding, blow molding, etc. at the time of melt-kneading, once compounded by a master batch or the like, and then melt-kneaded with other materials and molding may be performed.

The polyester-based resin composition of the present invention has good workability since the melt viscosity does not significantly increase at the time of molding by any molding method. In addition, the molded article molded from the polyester resin composition of the present invention is excellent in various performances such as strength in terms of good hydrolysis resistance.

Example

Hereinafter, the present invention will be described in more detail by way of Examples and Comparative Examples, but the present invention is not limited thereto.

[Evaluation items]

(1) solution viscosity

The melt-kneaded polyester resin composition was dried at 130° C. for 4 hours, and 0.15 g of the dried resin was dissolved in 30 mL of a mixed solution of phenol and tetrachloroethane (phenol/tetrachloroethane = 1/1 (weight ratio)). , It measured at 30 degreeC using the Canon Penske viscometer. The unit is (dl/g).

(2) Melt mass flow rate (MFR) (melt viscosity)

The melt-kneaded polyester resin composition was dried at 130° C. for 4 hours, and melt mass flow rate was performed at a test temperature of 270° C. and a test load of 2.16 kgf using a melt flow indexer (VR-4100, manufactured by Ueshima Corporation), which is a melt viscosity measuring instrument. (MFR) was measured. The unit is (g/10 min). The obtained MFR (g/10min) was made into the parameter|index of melt viscosity. It shows that melt viscosity is low, so that MFR value is large.

(3) Strength retention rate (hydrolysis resistance test)

The melt-kneaded polyester resin composition was flat-pressed at a temperature equal to or higher than the softening point to prepare a sheet having a thickness of about 300 µm, and a rectangular sheet having a width of 10 mm and a length of 70 mm was produced from the sheet.

Then, the tensile strength of the rectangular sheet produced by the tensile testing machine was measured. In addition, the produced rectangular sheet was put in a highly accelerated life tester (HAST CHAMBER EHS-210M manufactured by ESPEC), and samples were taken out after 24 hours and after 40 hours under the conditions of 121°C and 100%Rh, and the tensile tester The tensile strength of the rectangular sheet was measured. The average value of the tensile strength of each 5 sheets before and after a test was computed, and the strength retention was calculated|required as an evaluation index of hydrolysis resistance by the following formula.

Strength retention (%) = [(average value of tensile strength after test)/(average value of tensile strength before test)] x 100

(4) Crystallization evaluation

The melt-kneaded polyester resin composition was left to cool at room temperature, and the presence or absence of whitening of the resin was visually confirmed. Since a polyester resin whitens with crystallization, when whitening is confirmed, it shows that it is excellent in crystallization.

[Evaluation standard]

A: Yes

B: No bleaching

(5) Bleed-out resistance evaluation

The melt-kneaded polyester resin composition was pressed under the conditions described in (3) above for strength retention, and the presence or absence of bleed-out was visually checked for the obtained sheet.

Synthesis Example 1 (Synthesis of carbodiimide compound P1)

100 parts by weight of tolylene diisocyanate and 94.8 parts by weight of polyester polyol (Kurare Co., Ltd. "Kurare Polyol P-520", molecular weight 500) were placed in a reaction vessel equipped with a reflux tube and a stirrer, and stirred at 60° C. under a nitrogen stream for 1 hour. . Thereafter, 47.9 parts by weight of phenyl isocyanate and 2.2 parts by weight of a carbodiimidization catalyst (3-methyl-1-phenyl-2-phosphoene-1-oxide) were added, and the mixture was stirred at 110°C for 3 hours. After confirming that the absorption peak by the carbodiimide group around the ^{wavelength of 2150 cm -1} is generated by infrared absorption (IR) spectrum measurement and ^{the absorption peak by the isocyanate group around the wavelength of 2270 cm -1} has almost disappeared, the reactant is removed from the reaction vessel The mixture was taken out and cooled to room temperature to obtain a pale yellow carbodiimide compound P1.

Synthesis Examples 2-3 (Synthesis of carbodiimide compounds P2 to P3)

In Synthesis Example 1, carbodiimide compounds P2 to P3 were obtained in the same manner as in Synthesis Example 1 except that the raw material composition and reaction conditions were changed to the conditions shown in Table 1.

Synthesis Example 4 (Synthesis of carbodiimide compound P4)

100 parts by weight of tolylene diisocyanate, 45.6 parts by weight of phenyl isocyanate, and 0.3 parts by weight of a carbodiimidization catalyst (3-methyl-1-phenyl-2-phosphoene-1-oxide) were placed in a reaction vessel equipped with a reflux tube and a stirrer, and nitrogen It stirred at 110 degreeC under airflow for 3 hours. After confirming that the absorption peak by the carbodiimide group around the ^{wavelength of 2150 cm -1} is generated by infrared absorption (IR) spectrum measurement and ^{the absorption peak by the isocyanate group around the wavelength of 2270 cm -1} has almost disappeared, the reactant is removed from the reaction vessel The mixture was taken out and cooled to room temperature to obtain a pale yellow carbodiimide compound P4.

Synthesis Example 5 (Synthesis of carbodiimide compound P5)

In Synthesis Example 4, carbodiimide compound P5 was obtained in the same manner as in Synthesis Example 4 except that the raw material composition was changed to the conditions shown in Table 1.

Synthesis Example 6 (Synthesis of carbodiimide compound P6)

100 parts by weight of tetramethylxylene diisocyanate and 0.5 parts by weight of a carbodiimidization catalyst (3-methyl-1-phenyl-2-phosphoene-1-oxide) were placed in a reaction vessel equipped with a reflux tube and a stirrer, and 185 under a nitrogen stream It stirred at °C for 24 hours to obtain isocyanate-terminated tetramethylxylylenecarbodiimide. The absorption peak by the carbodiimide group around ^{wavelength 2150cm<-1>} was confirmed by infrared absorption (IR) spectrum measurement. It was 4.11% as a result of measuring the residual isocyanate group concentration (NCO%) measured by titration.

Next, the isocyanate-terminated tetramethylxylylenecarbodiimide obtained above was heated to 150° C., and 8.5 parts by weight of polyethylene glycol monomethyl ether (molecular weight 208) and polyester polyol (“Byron” manufactured by Toyobo Co., Ltd.) 220", molecular weight 3,000) 61.5 parts by weight was added, heated to 180° C., and reacted for 2 hours while stirring.

It was confirmed by infrared absorption (IR) spectrum measurement that ^{absorption of the isocyanate group having a wavelength of 2200 to 2300 cm -1} had disappeared, and the reaction product was taken out from the reaction vessel and cooled to room temperature to obtain a pale yellow transparent carbodiimide compound P6.

*1: TDI: tolylene isocyanate

*2: TMXDI: tetramethylxylylene diisocyanate

*3: Polyester polyol, Kuraray Co., Ltd. "Kurare Polyol P-520", molecular weight 500

*4: Polycarbonate polyol, "Duranol-5650E" manufactured by Asahi Kasehi Chemicals, molecular weight 500

*5: Polyester polyol, Toyobo Co., Ltd. "Byron 220", average molecular weight 3,000

*6: 3-methyl-1-phenyl-2-phosphoene-1-oxide

*7: Formula weight per 1 mol of carbodiimide group

Example 1

After melting 99 parts by weight of PET resin (manufactured by Sichuan Dongjae) with a laboratory mixer under the conditions of 270° C., 1 part by weight of the carbodiimide compound P1 obtained in Synthesis Example 1 was added, mixed for 3 minutes, and then polyester A system resin composition was obtained. Table 2 shows the evaluation results of the obtained polyester-based resin composition.

Examples 2-3, Comparative Examples 1-5

In Example 1, except having changed the compounding composition into the compounding composition shown in Table 2, it carried out similarly to Example 1, and obtained the polyester-type resin composition. Table 2 shows the evaluation results of the obtained polyester-based resin composition.

*1: Polyethylene terephthalate resin (PET resin), manufactured by Sacheon Copper

*2: Carbodiimide concentration (% by weight): Carbodiimide group (-N=C=N-) content of the polyester-based resin composition

= [Theoretical carbodiimide concentration (wt%) in the carbodiimide compound (B) x addition amount (wt. parts)/polyester resin composition (wt. parts)] x 100

From Table 2, it can be seen that the polyester-based resin compositions obtained in Examples 1 to 3 are excellent in hydrolysis resistance and crystallization, have low solution viscosity and melt viscosity, and are excellent in viscosity characteristics. Moreover, generation|occurrence|production of bleed-out was not confirmed in all the sheets obtained from the polyester resin composition of Examples 1-3, and it was excellent in bleed-out resistance.

Comparative Example 1 in which the carbodiimide compound (B) was added excessively, Comparative Example 4 not containing the carbodiimide compound (B), and Comparative Example containing the carbodiimide compound P6 using an aliphatic diisocyanate as the diisocyanate Example 5 was inferior to Examples 1-3 in hydrolysis resistance.

Moreover, the rise of melt viscosity was remarkable in Comparative Examples 2 and 3 containing the carbodiimide compounds P4 and P5 which do not have the residue of a diol compound in the carbodiimide compound.

Claims (8)

A polyester-based resin composition containing a polyester-based resin (A) and a carbodiimide compound (B) having a structure represented by the following general formula (1), wherein the content of the carbodiimide compound (B) is poly The polyester resin composition which is 0.1-10 weight part with respect to 100 weight part of total amounts of ester-type resin (A) and carbodiimide compound (B).

(Wherein, R ¹ represents a divalent organic group having at least one aromatic group. However, -N=C=N- is assumed to be directly bonded to the aromatic ring of ^{R 1 . R 2} represents a divalent residue of a diol compound. and x represents a number of 2 or more, and y represents a number of 1 or more.) The method according to claim 1,
The polyester-based resin composition wherein the diol compound is at least one selected from polyether polyol, polyester polyol, polycarbonate polyol, and alkylenediol. The method according to claim 1 or 2,
A polyester-based resin composition having a number average molecular weight of 100 to 40,000 of the diol compound. The method according to claim 1 or 2,
The polyester-based resin composition wherein R ¹ is at least one divalent residue selected from tolylene diisocyanate, tolidine diisocyanate, and diphenylmethane diisocyanate. The method according to claim 1 or 2,
A polyester-based resin composition having a carbodiimide equivalent weight of 200 to 1,500 of the carbodiimide compound (B). The method according to claim 1 or 2,
The polyester-based resin (A) is at least one selected from polyethylene terephthalate, polybutylene terephthalate, polybutylene succinate, polylactic acid, and polyhydroxyalkanoic acid. The method according to claim 1 or 2,
The polyester-based resin composition wherein the carbodiimide compound (B) is terminal-blocked with monoalcohol, monophenol, monoisocyanate, or monoamine. A molded article molded using the polyester-based resin composition of claim 1 or 2.