JP5793586B2 - POLYESTER RESIN COMPOSITION, PROCESS FOR PRODUCING THE POLYESTER RESIN COMPOSITION, AND MOLDED ARTICLE USING THE POLYESTER RESIN COMPOSITION - Google Patents

Description

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

Polyester resins are widely used for films, sheets, etc. because of their excellent transparency, mechanical strength, melt stability, solvent resistance, and recyclability. It is also used for cases.
However, since the polyester resin has a property of being easily hydrolyzed as compared with conventional general-purpose resins, a method of adding a carbodiimide compound has been studied for the purpose of improving the hydrolysis resistance. Yes.

  By blending and molding a carbodiimide compound into a polyester resin, the carbodiimide compound supplements the carboxyl group in the polyester resin and the carboxyl group generated by the decomposition of the ester group when kneaded at high temperature, resulting in a decrease in the initial performance of the molded product. Can be suppressed. Further, the durability of the molded product is improved by the carbodiimide compound remaining in the molded product.

For example, Patent Document 1 discloses a hydrolysis resistance for unsaturated polyester resins characterized by comprising a specific aliphatic or aromatic carbodiimide compound as a main component as a hydrolysis resistance stabilizer for unsaturated polyester resins. Stabilizers are disclosed.
In Patent Document 2, as a stabilizer against cleavage of polyester plastic by hydrolysis, it has a carbodiimide structure, and further has a urethane structure, a urea structure, or both of these structures, and is solid at 25 ° C., and has no carbodiimide structure. Carbodiimides bonded to aromatic carbon atoms are disclosed.
Patent Document 3 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. Is disclosed. Among them, a technique using a carbodiimide compound as a hydrolysis inhibitor and an adipic acid ester as a plasticizer is disclosed.
Patent Document 4 discloses a chemical compound 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. A polyester-polycarbodiimide copolymer having a structure and an adhesive composition containing the same are disclosed.

JP-A-9-249801 JP2000-256436 JP 2009-256405 A JP2013-75972A

In the technique of Patent Document 1, hydrolysis of the polyester resin can be suppressed, but at the time of melt kneading and molding, the carboxyl group in the polyester resin and the carbodiimide group react rapidly, thereby increasing the viscosity, Gelation may occur, and it may be difficult to produce a stable molded product.
In the technique of Patent Document 2, a solid carbodiimide can be obtained, and by adding this carbodiimide to a polyester plastic, strength retention at low temperature can be improved, but hydrolysis resistance is low, high temperature and high humidity There was a problem that the strength retention after storage below was inferior.
In the technique of Patent Document 3, the moldability can be improved by using a plasticizer. However, when a general plasticizer such as a phthalate ester is used, a bleed out from the molded body may occur depending on the amount added. In addition, there are problems in that the physical properties of the molded product are deteriorated and the environment and health problems are caused by the bleed-out product. Moreover, since these plasticizers do not have reactivity with a carboxyl group, the effect of inhibiting hydrolysis of the carbodiimide compound may be reduced, and improvement has been desired.
The technique of Patent Document 4 aims to obtain a coating film excellent in hydrolysis resistance and bending workability, and has a polyester-polycarbodiimide copolymer as a main component. Further, there have been cases where further improvement is desired in terms of cost.
The present invention provides a polyester-based resin composition that is excellent in hydrolysis resistance and bleed-out resistance and does not cause a significant increase in melt viscosity and solution viscosity, a method for producing the polyester-based resin composition, and the polyester An object of the present invention is to provide a molded article using the resin composition.

As a result of intensive studies to achieve the above object, the present inventor has found that the above problem can be solved by blending a specific carbodiimide compound in a specific ratio with respect to the polyester resin, The present invention has been completed.
That is, this invention is a molded article using the following polyester-type resin composition, the manufacturing method of this polyester-type resin composition, and this polyester-type resin composition.

[1] A polyester resin composition comprising a polyester resin (A) and a carbodiimide compound (B) represented by the following general formula (1), wherein the content of the carbodiimide compound (B) is polyester The polyester-type resin composition which is 0.1-8 mass parts with respect to 100 mass parts of total amounts of a system resin (A) and a carbodiimide compound (B).

In the formula, R ¹ represents a residue of a compound having one functional group reactive with isocyanate, and R ² represents a divalent aliphatic group having at least one alicyclic structure. However -N = C = N-shall be attached directly to the alicyclic structure R ^2. R ³ represents a divalent residue of the polyester diol. X represents the following general formulas (2) to (4)

Represents a group selected from: m represents the number of 1-20, n represents the number of 1-20, p represents the number of 1-5. A plurality of R ² and X may be the same or different.

[2] The polyester resin composition according to the above [1], wherein the polyester diol has a number average molecular weight of 1,000 to 40,000.
[3] The polyester resin composition according to the above [1] or [2], wherein R ² is a divalent residue of dicyclohexylmethane-4,4′-diisocyanate.
[4] The polyester resin composition according to any one of [1] to [3], wherein the carbodiimide compound (B) has a carbodiimide equivalent of 100 to 1,000.
[5] The above [1] to [4], 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-type resin composition in any one of.
[6] The method for producing a polyester resin composition according to the above [1] to [5], wherein the polyester resin (A) and the carbodiimide compound (B) are melt-kneaded.
[7] The method for producing a polyester resin composition according to the above [6], wherein the carbodiimide compound (B) is pelletized.
[8] A molded product molded using the polyester resin composition according to any one of [1] to [5].

  According to the present invention, a polyester-based resin composition that is excellent in hydrolysis resistance and bleed-out resistance and does not cause a significant increase in melt viscosity and solution viscosity, a method for producing the polyester-based resin composition, and A molded article using the polyester resin composition can be provided.

[Polyester 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) represented by the following general formula (1), which is a carbodiimide compound (B ) Is 0.1 to 8 parts by mass with respect to 100 parts by mass of the total amount of the polyester resin (A) and the carbodiimide compound (B).

In the formula, R ¹ represents a residue of a compound having one functional group reactive with isocyanate, and R ² represents a divalent aliphatic group having at least one alicyclic structure. However -N = C = N-shall be attached directly to the alicyclic structure R ^2. R ³ represents a divalent residue of the polyester diol. X represents the following general formulas (2) to (4)

Represents a group selected from: m represents the number of 1-20, n represents the number of 1-20, p represents the number of 1-5. A plurality of R ² and X may be the same or different.

The reason why the polyester resin composition of the present 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 clear, but is considered as follows.
Since the carbodiimide compound (B) represented by the general formula (1) contained in the polyester-based resin composition of the present invention has a polyester segment between polycarbodiimide groups, it imparts an appropriate distance between the polycarbodiimide groups. Thus, it is considered that a rapid increase in viscosity due to a crosslinking reaction during melt kneading could be suppressed.
Moreover, since the carbodiimide compound (B) can improve the solubility and dispersibility of the carbodiimide compound (B) in the polyester-based resin by having the polyester segment between the polycarbodiimide groups, the melt viscosity and the solution viscosity can be increased. It is considered that a molded product excellent in hydrolysis resistance and bleed out resistance could be obtained while suppressing the rise.
Furthermore, it is considered that by using a polycarbodiimide having a specific alicyclic structure as the polycarbodiimide, excellent hydrolysis resistance could be exhibited even at a carbodiimide group concentration lower than that of a conventional aliphatic polycarbodiimide.

<Polyester resin (A)>
As the polyester resin, any resin having an ester group can be used without particular limitation.
Examples of such polyester resins include polyethylene terephthalate (hereinafter also referred to as “PET”), polybutylene succinate (hereinafter also referred to as “PBS”), and 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 terephthalate-isophthalate copolymer, polylactic acid (hereinafter referred to as “PBT”). One or more selected from polyhydroxyalkanoic acids such as polybutyric acid (hereinafter also referred to as “PHA”) can be used.
Among these, from the viewpoint of economy and processability, preferably one or more selected from polyethylene terephthalate, polybutylene terephthalate, polybutylene succinate, polylactic acid, and polyhydroxyalkanoic acid, more preferably polyethylene terephthalate is there.
The content of the polyester resin (A) in the polyester resin composition of the present invention is preferably from 80 to 99.9 mass from the viewpoint of hydrolysis resistance, melt viscosity, and solution viscosity of the polyester resin composition. %, More preferably 85-99.8 mass%, still more preferably 90-99.7 mass%, and still more preferably 95-99.5 mass%.

<Carbodiimide compound (B)>
The carbodiimide compound (B) used in the present invention is represented by the following general formula (1).

In the formula, R ¹ represents a residue of a compound having one functional group reactive with isocyanate, and R ² represents a divalent aliphatic group having at least one alicyclic structure. However -N = C = N-shall be attached directly to the alicyclic structure R ^2. R ³ represents a divalent residue of the polyester diol. X represents the following general formulas (2) to (4)

Represents a group selected from: m represents the number of 1-20, n represents the number of 1-20, p represents the number of 1-5. A plurality of R ² and X may be the same or different.

(R ¹ )
In the general formula (1), R ¹ represents a residue of a compound having one functional group reactive with isocyanate (hereinafter also referred to as “component (a)”).
The carbodiimide compound (B) used in the present invention is improved in compatibility and storage stability of the carbodiimide compound (B) to the polyester resin by sealing the remaining terminal isocyanate with the component (a) which is a terminal blocking agent. It is considered that the quality can be improved.

[End sealant; component (a)]
Examples of the component (a) include monoalcohol, monophenol, monoisocyanate, and monoamine.
Examples of the monoalcohol include methanol, ethanol, cyclohexanol, polyethylene glycol monomethyl ether, and polypropylene glycol monomethyl ether.
Examples of the monophenol include phenol, methylphenol, dimethylphenol, naphthol and the like.
Examples of the monoisocyanate include methyl isocyanate, ethyl isocyanate, propyl isocyanate, lower alkyl isocyanate such as n-, sec- or ter-butyl isocyanate; alicyclic aliphatic isocyanate such as cyclohexyl isocyanate; phenyl isocyanate, tolyl isocyanate, dimethylphenyl Examples thereof include aromatic isocyanates such as isocyanate and 2,6-diisopropylphenyl isocyanate.
Examples of the monoamine include primary amines such as butylamine and cyclohexylamine; 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-based resin and enhancing the storage stability, it is preferably a monoalcohol or monoisocyanate, more preferably a monoalcohol, and even more preferably polyethylene glycol monomethyl ether or polypropylene. Glycol monomethyl ether, more preferably polyethylene glycol monomethyl ether.

(R ² )
In the general formula (1), R ² represents a divalent aliphatic group having at least one alicyclic structure. However -N = C = N-shall be attached directly to the alicyclic structure R ^2.
In the carbodiimide compound (B) used in the present invention, the carbodiimide group (—N═C═N—) can be directly bonded to the alicyclic structure, thereby increasing the reactivity with the carboxyl group. It is considered that excellent hydrolysis resistance could be exhibited even at a carbodiimide group concentration lower than that of polycarbodiimide.
Examples of the divalent aliphatic group having at least one alicyclic structure include a divalent residue of a diisocyanate having at least one alicyclic structure (hereinafter also referred to as “component (b)”).

[Diisocyanate; component (b)]
Examples of the component (b) include cyclohexane-1,4-diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, and methylcyclohexane diisocyanate. Among these, dicyclohexylmethane-4,4′-diisocyanate is preferable from the viewpoint of hydrolysis resistance, melt viscosity, and solution viscosity of the polyester resin composition.

(R ³ )
In the general formula (1), R ³ represents a divalent residue of a polyester diol (hereinafter also referred to as “component (c)”).
The carbodiimide compound (B) used in the present invention has a polyester segment as R ³ , so that the carbodiimide compound (B) has good compatibility with the polyester resin and improves the solubility and dispersibility of the carbodiimide compound (B) in the polyester resin. Therefore, it is considered that the increase in the melt viscosity and the solution viscosity was suppressed, and the hydrolysis resistance and bleed out resistance were improved.

[Polyester diol; component (c)]
The component (c) is not particularly limited as long as it is a diol having an ester group, and examples thereof include those having a chemical structure obtained by polycondensation of a polyvalent carboxylic acid and a polyhydric alcohol.
Examples of the polyvalent carboxylic acid include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, brassic acid, dimer acid, and hydrogenated products thereof, Alicyclic dibasic acids such as 2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, aromatic dibasic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, etc. It is preferable to use one or more dibasic acids.
Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, butanediol, neopentyl glycol, methylpentanediol, pentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, dodecanediol, and dimer diol. It is preferable to use one or more of glycols such as aliphatic glycol, cyclohexanediol, alicyclic glycol such as hydrogenated xylylene glycol, and aromatic ring-containing glycol such as xylylene glycol.
The number average molecular weight of the component (c) is preferably 1,000 to 40,000, more preferably 1,500 to 35, from the viewpoints of hydrolysis resistance, melt viscosity, and solution viscosity of the polyester resin composition. 1,000, more preferably 2,000 to 30,000. The number average molecular weight is measured by gel chromatography using polystyrene as a standard substance.

(M, n, p)
In general formula (1), m represents the number of 1-20 from the viewpoint of the hydrolysis resistance of a polyester-type resin composition, melt viscosity, and solution viscosity, Preferably it is 2-18, More preferably, 4- 16, more preferably 6-15.
In general formula (1), n represents the number of 1-20 from the same viewpoint, Preferably it is 2-18, More preferably, it is 4-16, More preferably, it is 6-15.
In general formula (1), p represents the number of 1-5 from the same viewpoint, Preferably it is 1-4, More preferably, it is 1-3.

(Carbodiimide equivalent)
The carbodiimide equivalent of the carbodiimide compound (B) (amount of chemical formula per 1 mol of carbodiimide group) is preferably 100 to 1,000 from the viewpoint of hydrolysis resistance, melt viscosity, and solution viscosity of the polyester resin composition. Preferably it is 150-850, More preferably, it is 200-600.

(Content of carbodiimide compound (B))
The content of the carbodiimide compound (B) is 100 parts by mass 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. Is 0.1 to 8 parts by mass, preferably 0.2 to 7 parts by mass, more preferably 0.3 to 6 parts by mass, and still more preferably 0.5 to 5 parts by mass.

<Method for producing carbodiimide compound (B)>
The carbodiimide compound (B) used in the present invention can be produced by a known method.
For example,
(I) A carbodiimidization reaction of diisocyanate (b) in the presence of a catalyst to obtain polycarbodiimide (hereinafter, also referred to as “component (d)”), and then (c) a terminal blocking agent (a ) And polyester diol (c), copolymerization reaction and end-capping reaction,
(Ii) a method of subjecting diisocyanate (b), polyester diol (c), and end-capping agent (a) to carbodiimidization reaction, copolymerization reaction, and end-capping reaction in the presence of a catalyst,
(Iii) A method in which a diisocyanate (b) and a polyester diol (c) are copolymerized and then a terminal blocking agent (a) and a catalyst are added to perform a carbodiimidization reaction and a terminal blocking reaction. It is done.
Among these, it is preferable to manufacture by the method (i) from the viewpoint of productivity.

(Production of polycarbodiimide (d))
The polycarbodiimide (d) is synthesized by subjecting the diisocyanate (b) to a carbodiimidization reaction in a solventless or inert solvent using an organophosphorus compound or an organometallic compound as a carbodiimidization catalyst. Can do.
Specific examples of the carbodiimidization catalyst include 3-methyl-1-phenyl-2-phospholene-1-oxide, 3-methyl-1-ethyl-2-phospholene-1-oxide, 1,3-dimethyl-2- Examples include phospholene-1-oxide, 1-phenyl-2-phospholene-1-oxide, 1-ethyl-2-phospholene-1-oxide, and 1-methyl-2-phospholene-1-oxide. Of these, 3-methyl-1-phenyl-2-phospholene-1-oxide, which is easily available industrially, is particularly preferable.
The reaction temperature of the carbodiimidization reaction is preferably 70 to 250 ° C, more preferably 100 to 230 ° C, and further preferably 150 to 200 ° C, from the viewpoint of productivity.
From the same viewpoint, the reaction time of the carbodiimidization reaction is preferably 1 to 50 hours, more preferably 10 to 40 hours, and further preferably 20 to 30 hours.
Although the usage-amount of a catalyst can be suitably determined according to the kind of catalyst to be used, Preferably it is 0.01-10 mass parts with respect to 100 mass of diisocyanate (b), More preferably, it is 0.05-5 mass parts, More preferably, it is 0.2-1 mass part.

(Copolymerization reaction)
The copolymerization reaction can be performed by reacting the polycarbodiimide (d) obtained above, the end-capping agent (a), and the polyester diol (c) under heating. Although there is no restriction | limiting in particular in the order which adds (d) component, (a) component, and (c) component, From a viewpoint of workability | operativity at the time of synthesis | combination, (d) component, (a) component, and (c) component are added. It is preferable to add them simultaneously. From the viewpoint of suppressing side reactions, the components (d) and (a) are added, and after confirming the completion of the reaction between the components (d) and (a), the components (c) Is preferably added.
The mixing ratio of the polycarbodiimide (d) and the polyester diol (c) is such that the terminal isocyanate group of the polycarbodiimide (d) is from the viewpoint of hydrolysis resistance, melt viscosity, and solution viscosity of the obtained polyester resin composition. The ratio of the number of moles to the number of moles of hydroxyl groups of the polyester diol (c) [NCO (d) / OH (c)] is preferably 1.20 to 2, more preferably 1.25 to 2, still more preferably 1.33-2.
The reaction temperature of the copolymerization reaction is preferably 40 to 250 ° C, more preferably 90 to 220 ° C, and still more preferably 130 to 200 ° C, from the viewpoint of productivity.
From the same viewpoint, the reaction time of the copolymerization reaction is preferably 5 minutes to 20 hours, more preferably 30 minutes to 10 hours, and further preferably 1 hour to 3 hours.

  From the viewpoint of productivity of the polyester resin composition, the obtained carbodiimide compound (B) is melt-mixed with the polyester resin (A) to form a master batch, or pelletized only with the carbodiimide compound (B) component. It is preferable to pelletize only with the carbodiimide compound (B) component. Pelletization can be performed by processing into a pellet shape with a known pelletizer.

<Other ingredients>
In the polyester resin composition, additives such as pigments, fillers, leveling agents, surfactants, dispersants, ultraviolet absorbers, antioxidants, flame retardants, colorants and the like are appropriately blended as necessary. Can do.

<Total content of polyester resin (A) and carbodiimide compound (B)>
The total content of the polyester resin (A) and the carbodiimide compound (B) in the polyester resin composition of the present invention is the viewpoint of the processability, hydrolysis resistance, melt viscosity, and solution viscosity of the polyester resin composition. Therefore, it is preferably 90 to 100% by mass, more preferably 92 to 100% by mass, and still more preferably 95 to 100% by mass.

[Production Method of Polyester Resin Composition]
The manufacturing method of the polyester-type resin composition of this invention is the method of melt-kneading the said polyester-type resin (A) and the said carbodiimide compound (B).
By using the carbodiimide compound (B), the production method of the present invention can suppress a significant increase in viscosity at the time of melt-kneading and is excellent in workability at the time of melt-kneading. It is thought that it is excellent in property.
Melt kneading can be performed using a known mixer equipped with a heating means. The order in which each material is charged into the mixer is not particularly limited, but the carbodiimide compound (B) and other components to be added as needed are added after the polyester-based resin (A) as a base is first charged and melted. It is preferable to input.
The time for melt-kneading can be appropriately determined according to the shape of the screw, the rotation speed, and the like, and is usually 1 to 30 minutes, preferably 1 to 10 minutes, and more preferably 1 to 5 minutes. Moreover, although the temperature at the time of melt-kneading changes with kinds of polyester-type resin used as a base, it is about 150-350 degreeC normally, Preferably it is 200-320 degreeC, More preferably, it is 240-300 degreeC.

The carbodiimide compound (B) used in the production method of the present invention is preferably pelletized.
Since conventional polycarbodiimide additives have a low melting point and are added to the extruder using a feeder or the like, they may melt at the inlet and become difficult to input, while powdered polycarbodiimide additives may be When dry blending with polyester resin pellets is added, the carbodiimide additive may segregate due to the difference in shape, resulting in uneven density. Furthermore, since the polycarbodiimide additive is slightly incompatible with the polyester resin, it is difficult to uniformly disperse it in the molded body at a low concentration.
On the other hand, the carbodiimide compound (B) used in the present invention can be pelletized and dry blended with a polyester resin to process a molded body. In particular, since the carbodiimide compound (B) having a large molecular weight has a high melting point, it can be easily pelletized. Segregation is unlikely to occur due to the pellet form, and since the polyester segment is present in the molecule, compatibility with the polyester resin is good, and even in low concentrations, it could be dispersed uniformly in the molded body of the polyester resin. It is done.
In addition, since it can be added directly to the polyester resin by dry blending, it is not necessary to prepare a masterbatch for each type of polyester resin, it is possible to reduce the number of manufacturing steps, and it is caused by the heat history due to masterbatch formation. It is considered that deactivation (reaction between ester resin and carbodiimide) could be avoided.

[Molded product using polyester resin composition]
When obtaining a molded product from the polyester-based resin composition of the present invention, it may be molded by extrusion molding, injection molding, blow molding or the like at the time of the above-mentioned melt-kneading, or once compounded into a masterbatch, etc. The material may be melt-kneaded and molded.
The polyester resin composition of the present invention has good workability because the melt viscosity does not significantly increase during molding in any molding method. Moreover, since the molded article shape | molded with the polyester-type resin composition of this invention has favorable hydrolysis resistance, it is excellent in various performances, such as intensity | strength.

  Hereinafter, although an example and a comparative example are given and the present invention is explained more concretely, the present invention is not limited to these.

[Evaluation item]
(1) Solution viscosity The melt-kneaded polyester-based resin composition is dried at 130 ° C. for 4 hours, 0.15 g of the dried resin is dissolved in 30 mL of phenol / tetrachloroethane = 1/1, and a Cannon Fenceke viscometer is used. And measured at 30 ° C. The unit is (dl / g).

(2) MFR (melt viscosity)
The melt-kneaded polyester resin composition is dried at 130 ° C. for 4 hours, and MFR (melt mass flow rate) at a test temperature of 270 ° C. and a test load of 2.16 kgf using a melt viscosity meter (VR-4100 manufactured by Ueshima Seisakusho Co., Ltd.). ) Was measured. The unit is (g / 10 min). The obtained MFR (g / 10 min) was used as an index of melt viscosity. The larger the MFR value, the lower the melt viscosity.

(3) Strength retention (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 strip sheet having a width of 10 mm and a length of 70 mm was prepared from the sheet.
Subsequently, the tensile strength of the produced strip sheet | seat was measured with the tension tester. Furthermore, the produced strip sheet was put into an advanced accelerated life test apparatus (HEST 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. The tensile strength of the strip sheet was measured with a tensile tester. Calculate the average value of the tensile strength of 5 sheets each before and after the test, and the strength retention rate (strength retention rate (%) = [average value of tensile strength after test] / [average value of tensile strength before test] ] × 100) was determined as an index for evaluating hydrolysis resistance.

(4) Bleed-out resistance evaluation About the sheet | seat obtained by pressing the polyester-type resin composition melt-kneaded on the conditions as described in said (3) intensity | strength retention, the presence or absence of bleed-out was confirmed visually.

Synthesis Example 1 (Synthesis of carbodiimide compound P1)
100 parts by mass of 4,4′-dicyclohexylmethane diisocyanate and 0.5 parts by mass of a carbodiimidization catalyst (3-methyl-1-phenyl-2-phospholene-1-oxide) are placed in a reaction tube equipped with a reflux tube and a stirrer. The mixture was stirred at 185 ° C. for 24 hours under a nitrogen stream to obtain isocyanate-terminated poly 4,4′-dicyclohexylmethanecarbodiimide.
An absorption peak due to a carbodiimide group having a wavelength of around 2150 cm ⁻¹ was confirmed by infrared absorption (IR) spectrum measurement. As a result of measuring NCO%, it was 3.78%, and the number of repeating units (hereinafter, also referred to as “polymerization degree”) represented by (—R ² —N═C═N—) was 9.0. there were.
Next, the isocyanate-terminated poly 4,4′-dicyclohexylmethane carbodiimide obtained above was heated to 150 ° C., and 7.9 parts by mass of polyethylene glycol monomethyl ether (molecular weight 208) and polyester diol (manufactured by Toyobo Co., Ltd. “ Byron 220 ", molecular weight 3,000) 57.3 parts by mass was added, and the mixture was heated to 180 ° C and reacted for 2 hours with stirring.
After confirming that the absorption of the isocyanate group having a wavelength of 2200 to 2300 cm ⁻¹ disappeared by infrared absorption (IR) spectrum measurement, it was taken out from the reaction vessel and cooled to room temperature to obtain a light yellow transparent carbodiimide compound P1.

Synthesis Examples 2 to 4 (Synthesis of carbodiimide compounds P2 to P4)
In Synthesis Example 1, carbodiimide compounds P2 to P4 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 described in Table 1.

Synthesis Example 5 (Synthesis of carbodiimide compound P5)
In Synthesis Example 1, except that the reaction conditions and the types of end-capping agents were changed to the conditions described in Table 1, and polyester diol (Toyobo Co., Ltd. “Byron 220”, molecular weight 3,000) was not added, In the same manner as in Synthesis Example 1, a carbodiimide compound P5 was obtained.

Synthesis Example 6 (Synthesis of pellet-shaped carbodiimide compound P6)
100 parts by mass of 4,4′-dicyclohexylmethane diisocyanate and 0.5 parts by mass of a carbodiimidization catalyst (3-methyl-1-phenyl-2-phospholene-1-oxide) are placed in a reaction tube equipped with a reflux tube and a stirrer. The mixture was stirred at 185 ° C. for 28 hours under a nitrogen stream to obtain isocyanate-terminated poly 4,4′-dicyclohexylmethane carbodiimide. An absorption peak due to a carbodiimide group having a wavelength of around 2150 cm ⁻¹ was confirmed by infrared absorption (IR) spectrum measurement. As a result of measuring NCO%, it was 2.92% (polymerization degree = 12.0).
Next, the isocyanate-terminated poly 4,4′-dicyclohexylmethane carbodiimide obtained above is heated to 150 ° C., 6.1 parts by mass of polyethylene glycol monomethyl ether (molecular weight 208) is added thereto, and the mixture is heated to 180 ° C. and stirred. Then, after reacting for 1 hour, it was taken out from the reaction vessel and cooled to room temperature to obtain a pale yellow transparent isocyanate piece-terminated 4,4′-dicyclohexylmethanecarbodiimide.
Next, 90.6 parts by mass of the above isocyanate-terminated 4,4′-dicyclohexylmethanecarbodiimide and 44.0 parts by mass of polyester diol (“Byron 220”, molecular weight 3,000, manufactured by Toyobo Co., Ltd.) Supplied to Toyo Seiki Seisakusho, Lab Plast Mill), melt kneading at 180 ° C., and processing the resulting strand into a pellet shape with a pelletizer, to obtain a pellet carbodiimide compound P6.
The obtained pellet-shaped carbodiimide compound P6 was confirmed to have lost absorption of an isocyanate group having a wavelength of 2200 to 2300 cm ⁻¹ by infrared absorption (IR) spectrum measurement.

Synthesis Example 7 (Synthesis of pellet carbodiimide compound P7)
In Synthesis Example 6, a carbodiimide compound P7 was obtained in the same manner as in Synthesis Example 6 except that the raw material composition and the reaction conditions were changed to the conditions described in Table 1.

Example 1
After 99.00 parts by mass of PET resin (manufactured by Chugoku Petrochemical) was melted at 270 ° C. with a lab mixer, 1.00 part by mass of the carbodiimide compound P1 obtained in Synthesis Example 1 was added and mixed for 3 minutes. A polyester resin composition was obtained. Table 2 shows the viscosity characteristics of the obtained polyester resin composition.

Examples 2-5, Comparative Examples 1-4
In Example 1, the polyester-type resin composition was obtained like Example 1 except having changed the compounding composition into the compounding composition of Table 2. Table 2 shows the viscosity characteristics of the obtained polyester resin composition.

Examples 6-8, Comparative Examples 5-8
The hydrolysis resistance of the polyester resin compositions obtained in each Example and Comparative Example and the presence or absence of bleed out were confirmed. The results are shown in Table 3.

From Tables 2-3, although the polyester-type resin composition of this invention is a carbodiimide density | concentration equivalent to a comparative example, neither has a significant raise of melt viscosity and solution viscosity, and hydrolysis resistance and resistance It turns out that it is excellent in bleed-out property.
On the other hand, the polyester resin composition of Comparative Example 1 containing P4 having a polycarbonate diol residue in the carbodiimide compound showed a significant increase in melt viscosity.
Moreover, the sheet | seat obtained from Comparative Example 2 which contains P5 which does not have the residue of a diol compound in a carbodiimide compound, and Comparative Example 4 which contains P3 which used aliphatic diisocyanate as diisocyanate (Comparative Examples 6- 8) was inferior in hydrolysis resistance to the sheets obtained from Examples 1-2 and 4 (Examples 6-8).

Claims (9)

A polyester resin composition comprising a polyester resin (A) and a carbodiimide compound (B) represented by the following general formula (1), wherein the content of the carbodiimide compound (B) is a polyester resin ( The polyester-type resin composition which is 0.1-8 mass parts with respect to 100 mass parts of total amounts of A) and a carbodiimide compound (B).

(Wherein R ¹ represents a residue of a compound having one functional group reactive with isocyanate, and R ² represents a divalent aliphatic group having at least one alicyclic structure, provided that —N═. C═N— is directly bonded to the alicyclic structure of R ^2. R ³ represents a divalent residue of the polyester diol, X is represented by the following general formulas (2) to (4).

Represents a group selected from: m represents the number of 1-20, n represents the number of 1-20, p represents the number of 1-5. A plurality of R ² and X may be the same or different. )   The polyester resin composition according to claim 1, wherein the polyester diol has a number average molecular weight of 1,000 to 40,000. The polyester resin composition according to claim 1 or 2, wherein R ² is a divalent residue of dicyclohexylmethane-4,4'-diisocyanate.   The polyester resin composition according to any one of claims 1 to 3, wherein the carbodiimide compound (B) has a carbodiimide equivalent of 100 to 1,000.   The polyester-based resin (A) is at least one selected from polyethylene terephthalate, polybutylene terephthalate, polybutylene succinate, polylactic acid, and polyhydroxyalkanoic acid. Polyester resin composition. The polyester-based resin composition according to any one of claims 1 to 5, wherein the compound having one functional group reactive with isocyanate is monoalcohol, monophenol, monoisocyanate, or monoamine. Production method of the polyester-based resin (A), the melt-kneading with the carbodiimide compound (B), a polyester resin composition according to claim 1-6. The method for producing a polyester resin composition according to claim 7 , wherein the carbodiimide compound (B) is pelletized. Claim 1-6 molded article molded by using the polyester resin composition according to any one of.