JP5717520B2 - Polyester resin composition and resin molded body - Google Patents

Description

  The present invention relates to a polyester-based resin composition and a resin molded body produced using the resin composition.

  Polyester resin, especially polyethylene terephthalate resin polymerized from ethylene glycol as glycol component and terephthalic acid as acid component has high crystallinity and excellent mechanical properties, strength, dyeability, stretchability, etc. It is a material and is used in various applications such as various fibers, films, sheets, and containers.

  However, in general, an amorphous polyester-based resin has a glass transition temperature of around 70 ° C. and lacks heat resistance. If the material is crystallized, heat resistance can be imparted, but transparency is impaired. Films and bottles can be given some heat resistance while maintaining transparency by stretching, but are difficult for injection-molded products and the like.

  In contrast, bulky bifunctional diol molecules other than ethylene glycol, such as 3,9-bis (1,1-dimethyl-2-dihydroxyethyl) -2,4,8,10-tetraoxaspiro- (5 5) -undecane (hereinafter referred to as spiroglycol), 2,2,4,4-tetramethyl-1,3-cyclobutanediol (hereinafter referred to as TMCD), (3S, 3aα, 6aα) -hexahydrofuro Polyester resin (hereinafter referred to as amorphous copolymer polyester) obtained by copolymerizing [3,2-b] furan-3α, 6β-diol (hereinafter referred to as isosorbide), tricyclodecane dimethanol or the like with a part of glycol component. Is referred to as a resin), and the crystallinity seen in polyethylene terephthalate resin is not observed, so that the transparency is maintained and the glass transition temperature There was improved as compared with the polyethylene terephthalate resin, it is known that the heat resistance is increased. Its glass transition temperature depends on the amount of bulky bifunctional diol copolymerization, but it is generally known to improve compared to polyethylene terephthalate resin. Applications that require heat resistance, such as medical equipment for sterilization by steam Is preferably used.

  These amorphous copolyester resins may be used alone, but are insufficient for applications requiring chemical resistance by being amorphous, and the above-mentioned polyethylene terephthalate resin Since the cost is comparatively high, there is a concern that the cost of the product increases. Thus, by blending with the polyethylene terephthalate resin, crystallinity can be imparted to the resin composition, and a resin composition suitable for applications requiring chemical resistance and the like can be obtained. In addition, the cost of the product can be kept low. Furthermore, the glass transition temperature of the resin composition can be arbitrarily set between the glass transition temperature of the amorphous copolyester resin and the glass transition temperature of the polyethylene terephthalate resin.

  On the other hand, regardless of the type of monomer used, the polyester resin has an ester bond in the molecular chain due to its molecular structure, and when wet heat stress is applied to the material over a long period of time, such as disinfection by steam, There was a problem that various properties of the material were likely to deteriorate.

  Thus, by adding various hydrolysis inhibitors to the polyester-based resin, a material that does not easily deteriorate even when wet heat stress is applied has been proposed. Examples of such hydrolysis inhibitors include oxazoline compounds, epoxy compounds, aromatic carbodiimide compounds, aliphatic carbodiimide compounds, and the like. (For example, see Patent Document 1)

JP 2008-150598 A

However, when a hydrolysis inhibitor, particularly a carbodiimide compound, is added to a polyester resin composition containing an amorphous copolymerized polyester resin, the formation of bumps due to the crosslinkable gel becomes a serious problem.
The bulky diol described above is synthesized by cyclizing a linear hydrocarbon. At that time, a part of the raw material may not be cyclized and a branched multifunctional alcohol may be formed. Although these polyfunctional alcohol impurities are removed from the glycol component in the purification step prior to polymerizing the amorphous copolyester, trace amounts of the component may still remain. And even if a very small amount of polyfunctional alcohol is used, the polymerized polyester is branched.
Amorphous copolymer polyester resin having such a branch reacts with a carbodiimide compound when melt-molded at a high temperature (about 290 ° C.) similar to that when melt-forming a crystalline polyethylene terephthalate resin. As a result, it becomes a cause due to the crosslinkable gel, and also increases the resin pressure inside a molding machine such as an extruder, thereby impairing stability during molding.

  That is, in the prior art, a polyester resin composition excellent in transparency, heat resistance, hydrolysis resistance, and stability during molding has not been provided.

  The present invention has been made in order to solve the above-described problems in the prior art, and its purpose is to provide a polyester resin composition excellent in transparency, heat resistance, hydrolysis resistance, and stability during molding. It is to provide.

  In order to solve the above-mentioned problems, the present inventors have conducted extensive studies on a polyester resin composition, and as a result, the following polyester resin composition has transparency, heat resistance, hydrolysis resistance, and molding. As a result, the present invention was completed.

That is, the first invention is a resin composition comprising a polyethylene terephthalate resin (A), an amorphous copolyester resin (B) having a glass transition temperature of 80 ° C. or higher, and a carbodiimide compound (C). The total amount of the resin composition is 100% by mass, the (A) is 50.0% by mass to 98.5% by mass, the (B) is 1.0% by mass to 49.9% by mass, (C) is contained in a ratio of 0.5% by mass or more and 5.0% by mass or less, (B) contains germanium, and residual germanium (Ge) content P [ppm] in (B) ] And the acid value Q [μeq / g NaOH] of (B) is a polyester-based resin composition having a product P × Q of 675 or less.

  Furthermore, another gist of the present invention resides in a resin molded body, particularly a heat-shrinkable resin molded body, produced using the polyester resin composition.

  According to the present invention, it is possible to obtain a resin composition excellent in transparency, heat resistance, hydrolysis resistance, and stability at the time of molding without generation of flaws or increase in resin pressure in the melt molding process. . Therefore, in addition to excellent durability in a high-temperature and high-humidity environment, it is possible to obtain a resin molded body that is particularly suitable as a substrate or coating material for various electronic components that also require transparency.

It is the schematic for demonstrating the definition of "butsu" prescribed | regulated by this invention.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with examples. However, the present invention is not limited to only these examples.

<Polyethylene terephthalate resin (A)>
The content of the polyethylene terephthalate resin (A) in 100% by mass of the polyester resin composition of the present invention needs to be 50.0% by mass or more and 98.5% by mass or less, and 60.0% by mass or more and 95%. More preferably, it is 7 mass% or less, and it is especially preferable that it is 70.0 mass% or more and 90 mass% or less.
When the content of the polyethylene terephthalate resin (A) is less than 50.0% by mass, it is preferable because the polyester resin composition of the present invention has insufficient chemical resistance due to a decrease in crystallinity and the cost becomes high. Absent. On the other hand, when the content of the polyethylene terephthalate resin (A) is more than 98.5% by mass, the crystallinity is too high and the transparency is impaired, which is not preferable.

  The polyethylene terephthalate resin (A) can be produced by a known method using a dicarboxylic acid component derived from terephthalic acid or an ester derivative thereof and a diol (dihydroxy) component derived from ethylene glycol or an ester derivative thereof.

The production method of the polyethylene terephthalate resin (A) is not particularly limited. For example, as a general polymerization method, a compound of antimony (Sb), germanium (Ge), titanium (Ti), or aluminum (Al) is used. In the presence of a polycondensation catalyst containing, etc., the dicarboxylic acid component and the diol component are polymerized while heating, and by-produced water or lower alcohol is discharged out of the system.
Specific examples of the Sb compound include antimony trioxide, antimony acetate, antimony tartrate, antimony potassium tartrate, antimony oxychloride, antimony glycolate, antimony pentoxide, and triphenylantimony.

Specific examples of Ge compounds include amorphous germanium dioxide, crystalline germanium dioxide powder or ethylene glycol slurry, a solution in which crystalline germanium dioxide is heated and dissolved in water, or a solution in which ethylene glycol is added and heat-treated. Is done.
Specific examples of the Ti compound include tetraethyl titanate, tetraisopropyl titanate, tetra-n-propyl titanate, tetraalkyl titanates such as tetra-n-butyl titanate and partial hydrolysates thereof, titanyl oxalate, titanyl ammonium oxalate, Examples include titanyl sodium oxalate, titanyl potassium oxalate, titanyl calcium oxalate, titanyl oxalate such as titanyl strontium oxalate, titanium trimellitic acid, titanium sulfate, titanium chloride and the like.

  Specific examples of the Al compound include carboxylates such as aluminum formate, aluminum acetate, aluminum propionate and aluminum oxalate, inorganic acid salts such as oxide, aluminum hydroxide, aluminum chloride, aluminum hydroxide chloride and aluminum carbonate, Examples include aluminum alkoxides such as aluminum methoxide and aluminum ethoxide, aluminum chelate compounds with aluminum acetylacetonate and aluminum acetylacetate, organoaluminum compounds such as trimethylaluminum and triethylaluminum, and partial hydrolysates thereof.

  In the case of an Al compound, an alkali metal compound or an alkaline earth metal compound may be used in combination. Examples of the alkali metal compound or alkaline earth metal compound include carboxylates such as acetates of these elements, alkoxides, and the like, and are added to the reaction system as powders, aqueous solutions, ethylene glycol solutions, and the like.

  In the present invention, the polymerization catalyst is not limited to the above-mentioned ones. Antimony-based, titanium-based, germanium-based, and aluminum-based catalysts, and these catalysts and alkali metal compounds, alkaline-earth metal compounds, phosphorus Polyethylene terephthalate resin (A) polymerized with various catalysts such as those used in combination with a series compound can be used. In the present invention, compounds such as manganese, zinc, calcium, magnesium, etc. used in the transesterification reaction, which is a pre-stage of the conventionally known polycondensation, can be used together. It is also possible to deactivate the catalyst and polycondense it with a phosphoric acid compound or the like. Furthermore, the production method of the polyethylene terephthalate resin (A) can be either batch type or continuous polymerization type. In addition, any polymerization method of solution polymerization method and solid phase polymerization method can be employed.

  When the polyethylene terephthalate resin (A) is produced, a small amount of dicarboxylic acid other than terephthalic acid may be used as the dicarboxylic acid component in addition to terephthalic acid. Examples of such dicarboxylic acids include isophthalic acid, 2-chloroterephthalic acid, 2,5-dichloroterephthalic acid, 2-methylterephthalic acid, 4,4-stilbene dicarboxylic acid, 4,4-biphenyldicarboxylic acid, orthophthalic acid 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, bisbenzoic acid, bis (p-carboxyphenyl) methane, anthracene dicarboxylic acid, 4,4-diphenyl ether dicarboxylic acid, 4,4-diphenoxyethanedicarboxylic acid Acids, aromatic dicarboxylic acids such as 5-Na sulfoisophthalic acid, ethylene-bis-p-benzoic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexane And aliphatic dicarboxylic acid components such as dicarboxylic acids. . Such dicarboxylic acid other than terephthalic acid is preferably 10 mol% or less based on the total dicarboxylic acid component contained in the polyethylene terephthalate resin (A).

  When the polyethylene terephthalate resin (A) is produced, a small amount of diol other than ethylene glycol may be used as the diol component in addition to ethylene glycol. Examples of such diols include diethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 2,2-dimethyl-1,3-propanediol, trans- or cis-2,2,4,4- Tetramethyl-1,3-cyclobutanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol , Decamethylene glycol, cyclohexanediol, p-xylenediol, bisphenol A, tetrabromobisphenol A, tetrabromobisphenol A-bis (2-hydroxyethyl ether), and the like. Such diols other than ethylene glycol are preferably 10 mol% or less based on the total diol component contained in the polyethylene terephthalate resin (A).

The intrinsic viscosity (IV) of the polyethylene terephthalate resin (A) is not particularly limited, but is usually 0.5 dl / g or more and 0.95 dl / g or less, and 0.6 dl / g or more and 0.9 or less. It is preferable. If the intrinsic viscosity (IV) is in the above range, it is preferable that the viscosity is too high so that a load is applied to the molding machine and mechanical properties are not deteriorated.
The intrinsic viscosity (IV) is obtained by dissolving 300 mg of a sample in 30 ml of a solvent (mixed solvent of phenol and 1,1,2,2-tetrachloroethane, mass ratio = 1: 1), and using an Ubbelohde viscometer. It can be obtained by measuring the sample drop time and calculating the intrinsic viscosity value.

The glass transition temperature of the polyethylene terephthalate resin (A) is measured by DSC (Differential Scanning Calorimetry) according to JIS K7121 by raising the temperature from −50 ° C. to 300 ° C. at a heating rate of 10 ° C./min. It is preferably not higher than ° C, more preferably not lower than 63 ° C and not higher than 80 ° C, and particularly preferably not lower than 65 ° C and not higher than 80 ° C.
If the glass transition temperature of a polyethylene terephthalate resin (A) is 60 degreeC or more, since the heat resistance of the obtained resin composition improves, it is preferable. Moreover, if it is 80 degrees C or less, since it is easy to promote crystallization, it is preferable. By adjusting the copolymerization component of the polyethylene terephthalate resin (A) within the above range, the glass transition temperature can be made a preferable range.

The melting point of the polyethylene terephthalate resin (A) is increased from −50 ° C. to 300 ° C. at a heating rate of 10 ° C./min by DSC (differential scanning calorimetry) according to JIS K7121, and held at 300 ° C. for 1 minute. Then, the temperature was lowered to −50 ° C. at a cooling rate of 10 ° C./min, held at −50 ° C. for 1 minute, and then measured again when the temperature was raised to 300 ° C. at a heating rate of 10 ° C./min. It is preferably 270 ° C. or lower, more preferably 230 ° C. or higher and 265 ° C. or lower, and particularly preferably 240 ° C. or higher and 260 ° C. or lower.
It is preferable that the melting point of the polyethylene terephthalate resin (A) is 220 ° C. or higher because the heat resistance of the crystallized resin molded body can be increased. Moreover, if it is 270 degrees C or less, since it can prevent that a resin composition heat-degrades in the case of a shaping | molding process, it is preferable. By adjusting the copolymerization component of the polyethylene terephthalate resin (A) within the above range, the melting point can be made a preferable range.

  As the polyethylene terephthalate resin (A), various commercially available raw materials can be preferably used. For example, trade name: “Novapex” (manufactured by Mitsubishi Chemical Corporation), trade name: “Byron” (manufactured by Toyobo Co., Ltd.) ), Trade name: “Belpet” (manufactured by Bell Polyester Co., Ltd.), trade name: “Tex Pet” (manufactured by Daewoo Japan Co., Ltd.), and the like.

<Amorphous Copolyester Resin (B)>
The content of the amorphous copolymer polyester resin (B) in the polyester resin composition of the present invention is required to be 1.0% by mass or more and 49.9% by mass or less, and 3.0% by mass. It is more preferable that it is 40.0 mass% or less, and it is especially preferable that it is 5.0 mass% or more and 30.0 mass% or less. Content of an amorphous copolyester resin (B) is 1.0. If it is less than mass%, it is difficult to achieve both transparency and heat resistance for the polyester resin composition of the present invention. On the other hand, when the content of the amorphous copolyester resin (B) is more than 49.9% by mass, the polyester resin composition of the present invention has insufficient chemical resistance due to a decrease in crystallinity and costs. In addition to being expensive, as will be described later, it is not preferable because the formation of burrs caused by the crosslinkable gel and the increase in the resin pressure during melt molding are promoted and the stability during molding deteriorates.

  In accordance with JIS-K7121, the amorphous copolyester resin (B) was heated from −50 ° C. to 300 ° C. at a heating rate of 10 ° C./min according to JIS-K7121, and kept at 300 ° C. for 1 minute. When the temperature was lowered to 50 ° C. at a cooling rate of 10 ° C./min, held at −50 ° C. for 1 minute, and then heated again to 300 ° C. at a heating rate of 10 ° C./min, a clear melting peak at the second temperature rise Is a polyester-based resin that does not appear, and uses two or more kinds of diol components. At least one of these diol components is preferably a relatively bulky diol having a cyclic structure in the molecule. The cyclic structure is preferably a cyclic structure not including a double bond, and may contain an oxygen atom derived from an ether bond in the molecule.

  Examples of such bulky diol components include spiro glycol, TMCD, isosorbide, and tricyclodecane dimethanol. Among these, in particular, spiroglycol, TMCD, isosorbide and the like increase the glass transition temperature of the amorphous copolyester resin (B) when used as the diol component, and the heat resistance of the polyester resin composition of the present invention. This is preferable.

  Examples of diol components other than the above include diethylene glycol, ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 1,4-butanediol, neo Pentyl glycol, 1,5-pentanediol, 1,6-hexanediol, decamethylene glycol, cyclohexanediol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, p-xylenediol, bisphenol A, tetrabromo Examples thereof include bisphenol A and tetrabromobisphenol A-bis (2-hydroxyethyl ether). Among these, ethylene glycol is preferable because it is industrially inexpensive and easy to control crystallinity and glass transition temperature. Further, 1,3-cyclohexanedimethanol does not increase the glass transition temperature of the amorphous copolymer polyester resin (B), but the impact resistance of the amorphous copolymer polyester resin (B) It is also preferable because transparency can be improved.

The content ratio of the bulky diol component in the amorphous copolymer polyester resin (B) is 20 mol% or more with respect to the total diol component contained in the amorphous copolymer polyester resin (B). It is preferably 30 mol% or more, more preferably 40 mol% or more. Further, the upper limit of the content ratio is not particularly limited, but if the content ratio is too high, depending on the type of the diol component, there is a risk that the fluidity at the time of melting may be impaired, so that it is 70 mol% or less Is preferred.
When the bulky diol component is 20 mol% or more, the glass transition temperature of the amorphous copolyester resin (B) can be increased, and heat resistance can be imparted to the resin composition.

  Examples of the dicarboxylic acid component used in the amorphous copolyester resin (B) include terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2,5-dichloroterephthalic acid, 2-methylterephthalic acid, 4-stilbene dicarboxylic acid, 4,4-biphenyl dicarboxylic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, bisbenzoic acid, bis (p-carboxyphenyl) methane, anthracene dicarboxylic acid, Aromatic dicarboxylic acids such as 4,4-diphenyl ether dicarboxylic acid, 4,4-diphenoxyethane dicarboxylic acid, 5-Na sulfoisophthalic acid, ethylene-bis-p-benzoic acid, adipic acid, sebacic acid, azelaic acid, dodecane Diacid, 1,3-cyclohexanedicarboxylic acid, 1,4-cycl Aliphatic dicarboxylic acid component such as hexane dicarboxylic acid. These dicarboxylic acid components may be used alone or in admixture of two or more. In the present invention, terephthalic acid and isophthalic acid are particularly preferred as the dicarboxylic acid because it is industrially inexpensive and the synthesized amorphous copolyester resin (B) is chemically stable.

  Although it does not specifically limit about the manufacturing method of an amorphous copolymerization polyester-type resin (B), Preferably illustrate the method similar to what was illustrated about the manufacturing method of above described polyethylene terephthalate resin (A). Can do.

  The intrinsic viscosity (IV) of the amorphous copolyester resin (B) is not particularly limited, but is usually 0.5 dl / g or more and 0.9 dl / g or less, and 0.6 dl / g or more and 0. .8 or less is preferable. If the intrinsic viscosity (IV) is in the above range, it is preferable because both the mechanical strength of the molded article and the fluidity at the time of melting can be achieved. The intrinsic viscosity (IV) can be measured by the same method as that for the polyethylene terephthalate resin (A).

The glass transition temperature of the amorphous copolyester resin (B) is measured by heating at a heating rate of 10 ° C./min from −50 ° C. to 300 ° C. by DSC (differential scanning calorimetry) according to JIS K7121, The temperature must be 80 ° C. or higher, more preferably 85 ° C. or higher, still more preferably 90 ° C. or higher, and particularly preferably 95 ° C. or higher. Moreover, although the upper limit of glass transition temperature is not specifically limited, Usually, it is 130 degrees C or less.
If the glass transition temperature of the amorphous copolymerized polyester resin (B) is less than 80 ° C., the polyester resin composition of the present invention is not preferable because the heat resistance is insufficient. A glass transition temperature can be made into a preferable range by adjusting the copolymerization component of an amorphous copolymerization polyester-type resin (B) in the said range.

  As the amorphous copolyester resin (B), various commercially available raw materials can be preferably used. For example, trade name: “ALTERSTER” (manufactured by Mitsubishi Gas Chemical Co., Ltd., using spiroglycol), trade name : “TRITAN” (manufactured by EASTMAN Chemical Co., Ltd., using TMCD) and trade name: “ECOZEN” (manufactured by SK Chemical Co., Ltd., using isosorbide).

<Carbodiimide compound (C)>
The polyester resin composition of the present invention contains a carbodiimide compound (C) from the viewpoint of hydrolysis resistance. The carbodiimide compound used in the present invention reacts with a functional group that promotes hydrolysis of the polyester, such as a hydroxyl group or a carboxyl group present in a molecular chain, at the time of molding or in a high temperature and high humidity test. Hydrolysis can be prevented. For example, it is known that when a carboxyl group is contained in the molecular chain of polyester, it reacts with carbodiimide to change to a non-toxic urea structure.

The content of the carbodiimide compound (C) in 100% by mass of the polyester-based resin composition of the present invention needs to be 0.5% by mass or more and 5.0% by mass or less, and 0.5% by mass or more and 3% by mass. It is more preferably 0.0% by mass or less, and particularly preferably 1.0% by mass or more and 2.0% by mass or less.
When the content of the carbodiimide compound (C) is less than 0.1% by mass, hydrolysis resistance is insufficient, which is not preferable. When the content of the carbodiimide compound (C) is more than 5.0% by mass, a large amount of irritating gas derived from the decomposition product of the carbodiimide compound (C) is generated during the molding process, or the molded product is crosslinkable. This is not preferable because problems such as the occurrence of looseness derived from the gel occur.

  Examples of the carbodiimide compound (C) include those having a basic structure represented by the following general formula (1).

  In the general formula (1), n is an integer of 1 or more, and R represents an organic bond unit. For example, R can be either aliphatic, alicyclic, or aromatic. In addition, n is usually selected from an appropriate integer between 1 and 500. When n is 2 or more, R may be the same or different in each repeating unit in the general formula (1).

  Specific examples of the carbodiimide compound (C) include disubstituted monomers such as bis (propylphenyl) carbodiimide, bis (dipropylphenyl) carbodiimide, poly (4,4′-diphenylmethanecarbodiimide), poly (p- Polymers such as phenylenecarbodiimide), poly (m-phenylenecarbodiimide), poly (tolylcarbodiimide), poly (diisopropylphenylenecarbodiimide), poly (methyl-diisopropylphenylenecarbodiimide), poly (triisopropylphenylenecarbodiimide), aromatic polycarbodiimide, etc. Furthermore, the monomer of these polymers can be mentioned. These carbodiimide compounds may be used alone or in combination of two or more. As the polymer of the carbodiimide compound, those having a mass average molecular weight of 2,000 to 50,000 are preferable. Among these carbodiimide compounds, aromatic polycarbodiimide compounds are particularly preferably used because they exhibit excellent hydrolysis resistance with respect to the polyester resin composition of the present invention.

  As such a carbodiimide compound (C), various commercially available raw materials can be preferably used. For example, trade names: “Stabaxol series” (manufactured by Rhein Chemie), trade names “Carbodilite HMV8CA”, “Carbodilite LA” -1 "(manufactured by Nisshinbo Industries, Inc.).

  Moreover, in this invention, the commercially available masterbatch which added these carbodiimide type compounds (C) to polyester type resins, such as a polyethylene terephthalate resin, at high concentration can also be used preferably.

<Stability during molding>
The polyester resin composition of the present invention contains the polyethylene terephthalate resin (A), the amorphous copolyester resin (B), and the carbodiimide compound (C) in a specific range ratio. Thus, a polyester resin composition having excellent transparency, heat resistance, and hydrolysis resistance is obtained.
However, as described above, in the conventional technique, a high temperature required for melt-molding a crystalline polyethylene terephthalate resin (A) from an amorphous copolyester resin (B) containing a bulky diol component. When melt molding at (about 290 ° C.), it reacts with the carbodiimide compound (C) having a plurality of reaction points, thereby causing a chipping caused by the crosslinkable gel and a molding machine such as an extruder. There is a problem that the resin pressure is increased inside the glass, causing the stability during molding to be impaired.

In the first aspect of the present invention, as a means for solving this problem, the residual germanium (Ge) content P [ppm] in the amorphous copolyester resin (B) and the acid (B) By setting the product P × Q of the value Q [μeq / g NaOH] to 675 or less, there is very little formation of solids due to the crosslinkable gel, and the resin pressure does not increase inside the molding machine, and stability during molding Thus, it has become possible to provide a polyester resin composition having excellent properties.
The value of P × Q is more preferably 650 or less, further preferably 625 or less, and particularly preferably 600 or less. When the value of P × Q exceeds 675, when the polyester-based resin composition of the present invention is melt-molded, the generation of solids due to the crosslinkable gel increases, or the resin pressure rises inside the molding machine. However, it is not preferable because stability during molding is impaired. On the other hand, the lower limit of the value range of P × Q is not particularly limited, but is usually 150 or more when a Ge compound is used as a polymerization catalyst, and is 0 when a Ge compound is not used as a polymerization catalyst.

When the amorphous copolymerized polyester resin (B) is polymerized, various catalysts are used as described above, but these catalysts are difficult to remove even after the completion of the polymerization reaction. Residues in products made of resin. In the present invention, it has been found that the residual amount of Ge catalyst is particularly important in connection with the generation of the blisters caused by the crosslinkable gel, and the smaller the residual amount, the harder the bumps are generated. . For example, it is not recognized that the residual Ti content derived from the Ti catalyst used in combination with the Ge catalyst contributes significantly to the generation of bumps.
Of several catalysts, it is not clear why only the residual Ge content is related to the generation of lumps, but it reacts with carbodiimide present in the molecular chain of the amorphous copolyester resin (B). This is considered to be because some potential functional group (for example, carboxyl group, hydroxyl group, etc.) reacts with the carbodiimide-based compound (C) to exhibit some accelerating effect.

  The residual Ge content P [ppm] in the amorphous copolyester resin (B) is preferably 54 or less, more preferably 50 or less, and particularly preferably 46 or less. However, even if the residual Ge content P [ppm] exceeds 54, the value of the acid value Q [μeq / g NaOH] of the amorphous copolyester resin (B) described later is 675 as the product P × Q. It may be in the range as follows. On the other hand, when it is necessary to use Ge as a polymerization catalyst due to technical restrictions during the polymerization of the amorphous copolyester resin (B), the lower limit of the residual Ge content P [ppm] is usually 30 or more. is there. When Ge is not used as a polymerization catalyst, it can be set to zero.

  The residual Ge content P [ppm] in the amorphous copolymerized polyester resin (B) is determined by performing an inductively coupled plasma emission spectrometer (PB) after performing microwave acid decomposition on the pellet sample (B). ICP-OES) was used for measurement.

  On the other hand, the acid value of the amorphous copolymer polyester resin (B) is considered to correspond to the number of carboxyl groups contained in the molecular chain of the amorphous copolymer polyester resin (B). That is, the amorphous copolymer polyester resin having an acid value of a certain value or less has little branching in the polymer molecule, and even when reacted with the carbodiimide compound (C), gelation due to a crosslinking reaction or the like does not occur. As a result, it leads to a decrease in lumps.

  The acid value Q [μeq / g NaOH] in the amorphous copolyester resin (B) is preferably 12.5 or less, more preferably 11.0 or less, and 10.0 or less. It is particularly preferred. However, even if the acid value Q [μeq / g NaOH] exceeds 12.5, the value of the residual Ge content P [ppm] in the amorphous copolymer polyester resin (B) is the product P ×. It may be in a range where Q is 675 or less. On the other hand, the lower limit of the acid value Q [μeq / g NaOH] is usually 3.0 or more due to technical limitations related to the removal of impurities.

前記数式（Ｉ）において、Ａは試料滴定に要した０．１規定の水酸化ナトリウムの量［μＬ］であり、Ｂは空試験に要した０．１規定の水酸化ナトリウムの量［μＬ］であり、ｆは０．１規定の水酸化ナトリウムの力価（無次元数）であり、Ｗは非晶性共重合ポリエステル系樹脂（Ｂ）のサンプル量［ｇ］を示す。 The acid value Q [μeq / g NaOH] of the amorphous copolymer polyester resin (B) was measured as follows. First, the pellet sample (B) was pulverized and dissolved in benzyl alcohol by heating. Chloroform was added to the solution, cooled, phenol red indicator was added, and titration was performed with a 0.1N sodium hydroxide benzyl alcohol solution. The acid value Q at this time is calculated | required by the following numerical formula (I).

In the above formula (I), A is the amount of 0.1 N sodium hydroxide required for the sample titration [μL], and B is the amount of 0.1 N sodium hydroxide required for the blank test [μL]. F is the titer (dimensionless number) of 0.1N sodium hydroxide, and W is the sample amount [g] of the amorphous copolyester resin (B).

<Polyester resin composition>
The polyester-based resin composition according to the second aspect of the present invention is a polyester-derived resin composition having a thickness of 50 to 150 μm formed by melt-extruding the resin composition using a single screw extruder and having a cross-section of polyester cross-linked per 1000 cm ³ of volume. The number needs to be 1.0 or less, more preferably 0.7 or less, and particularly preferably 0.5 or less.
If the number of bumps is more than 1.0, the increase in the resin pressure at the time of melt molding is often accompanied, the stability at the time of molding becomes insufficient, and the polyester resin composition is used. The yield of the resin molding to be produced is deteriorated. Further, there is a concern that the quality of the resin molded body is deteriorated.

The irregularity derived from the crosslinked polyester in the present invention is defined as follows. That is, the outer shape is a continuous region in the film having a thickness T 1.2 times or more larger than the average thickness _Tf measured and calculated in the direction perpendicular to the flow direction of the film. Is the area π × (10 × T _max ) ² or less of a circle having a diameter 20 times the maximum thickness T _max , and the ratio of the maximum length to the minimum length that can be taken in the region is 5 or less. is there. (See Figure 1)
Moreover, the spectrum obtained by infrared spectroscopy is very similar to the spectrum obtained on average from the film. Furthermore, even when the temperature is raised to 300 ° C. under a microscope, the entire region does not melt.

  When such cuts are cut, an inorganic substance may or may not be detected from the inside. However, what kind of substance is contained in the inside of the material other than the component derived from the polyester crosslinked product is not related to the definition of the material derived from the polyester crosslinked material in the present invention. In the present invention, the product derived from the cross-linked polyester is a product produced by the interaction and cross-linking of a carbodiimide compound, an amorphous copolyester resin, and a polyethylene terephthalate resin. It may or may not take up inorganic substances that are present.

The number of protrusions is measured by the following method. First, the polyester resin composition of the present invention is melted using a single screw extruder. At this time, various known single-screw extruders can be used as the single-screw extruder. Moreover, as a diameter of the screw to be used, it is preferable that it is 50 mm or more and 100 mm or less, and it is preferable to use a full flight type screw from a viewpoint of suppressing the production | generation of a polyester crosslinked material.
In order to smoothly extrude the crystalline polyethylene terephthalate resin (A) contained in the polyester resin composition of the present invention, the set temperature of the single-screw extruder is gradually increased from the raw material charging hopper side toward the die side. It is preferable to keep constant at 290 ° C. from the middle of the compression section to the die of the extruder. Moreover, you may provide a mesh, a filter pack, etc. between the front-end | tip of an extruder, and a nozzle | cap | die.

Next, it is extruded from a die set to a lip gap of 0.1 to 1 mm, and is rapidly cooled by a cooling roll or water cooling to be molded. As the die used at this time, a known die such as a flat die such as a T die or a round die can be adopted. Next, adjustment is performed by stretching, sizing or the like so that the thickness of the obtained film is in the range of 50 μm to 150 μm. The film thickness may be adjusted by adjusting the lip gap or the take-off speed when the film is formed. In addition, as long as the thickness as a whole is in the above-described range, a plurality of films may be stacked or a tube-shaped film may be folded. The film whose thickness has been adjusted is a material contained inside the film, which is checked by a method of contact by hand, a method using a foreign matter measuring machine of the film, or visual observation while unwinding at an appropriate speed. Is determined according to the above definition, and if it is determined to be a chip, the number of the chip is recorded.
This operation is continued until the unwinding amount of the film reaches about 100 m, and the number of bumps per 1000 cm ³ is determined from the detected number of bumps, film thickness, film width, and unrolled film length.

  Furthermore, the gel permeation chromatography measurement after processing the film which shape | molded the polyester-type resin composition of this invention for 30 hours on the conditions of temperature 130 degreeC, relative humidity 85%, and absolute vapor pressure of about 0.23 MPa. The polystyrene-reduced weight average molecular weight value obtained by the above is preferably 40% or more, more preferably 50% or more, and more preferably 60% or more of the value of the weight average molecular weight of the film before processing. It is particularly preferred. When the value of the weight average molecular weight after the treatment is within the above range, the polyester resin composition of the present invention has excellent hydrolysis resistance.

The glass transition temperature of the polyester resin composition of the present invention is measured by heating at a heating rate of 10 ° C./min from −50 ° C. to 300 ° C. by DSC (differential scanning calorimetry) according to JIS K7121, and 75 ° C. It is preferable that it is above, it is more preferable that it is 80 degreeC or more, and it is especially preferable that it is 85 degreeC or more. Moreover, although the upper limit of glass transition temperature is not specifically limited, Usually, it is 100 degrees C or less.
If the glass transition temperature of the polyester resin composition is 75 ° C. or higher, it is preferable because heat resistance can be imparted to a resin molded body produced using the resin composition.

  The polyester-based resin composition of the present invention can be produced by various ordinary known methods. Polyethylene terephthalate resin (A), amorphous copolyester resin (B), carbodiimide compound (C), and other additives as necessary are premixed, and a single-screw or multi-screw extruder, A method of supplying to a generally known melt mixer such as a tumbler, V-type blender, Banbury mixer, kneader, mixing roll and kneading at a temperature of about 280 ° C. to 320 ° C., and an extruder having two or more supply ports The method etc. which supply the component measured separately to each supply port are mentioned.

  The order of mixing the raw materials is not particularly limited, and the amorphous terephthalate resin (B), the carbodiimide compound (C), and other additives are directly mixed with the polyethylene terephthalate resin (A) to be used. , Melt-kneading method, amorphous copolymer polyester resin (B), carbodiimide compound (C), other additives, etc. in polyethylene terephthalate resin (A) at a high concentration (typically 5 to 5) A master batch mixed to about 60% by mass) is prepared separately, and this is mixed with the polyethylene terephthalate resin (A) by adjusting the concentration. A method of melt kneading raw materials, or a part of the raw material remains with a side feeder during melt kneading with a single or twin screw extruder A method of mixing the raw materials, any method may be used. Moreover, about a small amount additive component, after kneading | mixing another component by the said method etc. and pelletizing, it can also add separately when shape | molding the resin molding mentioned later.

<Resin molding>
Moreover, there is no restriction | limiting in particular also in the method of manufacturing a resin molding using the polyester-type resin composition of this invention, A polyethylene terephthalate resin (A), an amorphous copolymerization polyester-type resin (B), a carbodiimide type compound ( C) and, if necessary, other additives are premixed, and usually known melt mixing such as single-screw or multi-screw extruder, tumbler, V-type blender, Banbury mixer, kneader, mixing roll as described above. The pellet may be obtained using a machine, and the pellet may be used as a raw material for extrusion molding or injection molding. The raw material that has been premixed may be a flat die such as a T die, or a single screw or a multi-piece with a round die attached to the tip. A resin molded body such as a sheet may be obtained directly by feeding into a shaft extruder.

The resin molded product of the present invention produced by the above method is a variety of resin molded products such as films, sheets, tubes, plates, fibers, injection molded products, etc., and requires transparency, heat resistance, and hydrolysis resistance. Can be suitably used for various purposes.
Among them, the heat-shrinkable resin molded product of the present invention, such as a shrink film and a shrink tube, is used in addition to various packaging materials that require transparency, heat resistance, and hydrolysis resistance, and excellent durability in a high temperature and high humidity environment. In addition, it can be suitably used as a substrate or coating material for various electronic components that also require transparency.

  Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

<Raw materials used>
The raw materials used in Examples and Comparative Examples are shown below.
Polyethylene terephthalate resin (A): isophthalic acid copolymerized polyethylene terephthalate (Mitsubishi Chemical Corporation, trade name: Novapex BK2180, glass transition temperature: 74.9 ° C., melting point: 247 ° C., limiting viscosity: 0.7 dl / g , Isophthalic acid content with respect to all carboxylic acid components: 4 mol%)
Amorphous copolymer polyester resin (B1): Spiroglycol copolymer polyester resin (Mitsubishi Gas Chemical Co., Ltd., trade name: ALTERSTER 45, glass transition temperature: 109 ° C., intrinsic viscosity: 0.65 dl / g, Spiroglycol content with respect to all diol components: 45 mol%)
Amorphous copolyester resin (B2): TMCD copolyester resin (manufactured by EASTMAN Chemical Co., Ltd., trade name: TRITAN FX-100, glass transition temperature: 110 ° C., intrinsic viscosity: 0.77 dl / g TMCD content with respect to all diol components: 21 mol%)
Hydrolysis inhibitor-containing masterbatch (MB): Aromatic polycarbodiimide compound-containing polyethylene terephthalate resin masterbatch (manufactured by Rhein Chemie Japan, trade name: Stabaxol KE7646, aromatic polycarbodiimide compound (C) content : 15% by mass)

<Evaluation>
Evaluation methods for various raw materials and resin compositions displayed in the present specification were performed as follows.

(1) Intrinsic viscosity (IV)
Dissolve 300 mg of sample in 30 ml of solvent (mixed solvent of phenol and 1,1,2,2-tetrachloroethane, mass ratio = 1: 1), measure the sample dropping time using an Ubbelohde viscometer, and determine the intrinsic viscosity The value was obtained by calculation.

(2) Glass transition temperature Using a differential scanning calorimeter (trade name: Pyris1 DSC, manufactured by Perkin Elmer Co., Ltd.), about 10 mg of a sample was applied at a heating rate of 10 ° C./min to −50 ° C. to 300 ° C. according to JIS K7121. The temperature at the intersection of a straight line obtained by extending the base line on the low temperature side to the high temperature side and a broken line drawn at a point where the slope of the step change part of the glass transition is maximized The outer glass transition start temperature was determined.

(3) High temperature and high humidity resistance The raw materials listed in Table 1 were premixed, and the film was formed from a die set to a lip gap of 0.7 mm by a single screw extruder adjusted to a maximum temperature of 290 ° C. Was cut to obtain a film having a width of 30 mm and a thickness of 110 μm. This film was allowed to stand for 90 minutes in a constant temperature bath at 85 ° C., and further allowed to stand at room temperature for 2 hours, which was used as a film before the test. Thereafter, the film was manufactured using a super accelerated life test apparatus (PC-422R7 type) manufactured by Hirayama Seisakusho Co., Ltd., in accordance with JIS C-60068-2-66, at a temperature of 130 ° C., a relative humidity of 85%, and absolute. The vapor pressure was set to about 0.23 MPa, the test was performed for 30 hours, and then left to reach room temperature. The mass average molecular weight of the film before and after the test was measured by the method described in the following (4), and the ratio of the mass average molecular weight of the film after the test to the mass average molecular weight of the film before the test was calculated.

(4) Mass average molecular weight HLC-8120GPC manufactured by Tosoh Corporation was used as a measuring machine. Chloroform was used as a solvent, and the solution concentration was adjusted by dissolving 25 mg of sample with 0.25 ml of hexafluoroisopropanol and further adding 5 ml of chloroform. Further, the column used was a column in which two KD-80M and KD-803 (manufactured by Showa Denko KK) were connected in series, the solution injection volume was 10 μl, the solvent flow rate was 1.0 ml / min, and the solvent temperature was 40. Measurement was performed at 0 ° C., and a mass average molecular weight was calculated in terms of polystyrene (an average value of 10 samples was calculated and rounded down to the nearest 100). The weight average molecular weight of the standard polystyrene used is 2,000,000, 670,000, 110,000, 35,000, 10,000, 4,000, 600.

(5) Residual Ge Content in Amorphous Copolyester Resin After performing microwave acid decomposition on the pellet sample of amorphous copolyester resin, inductively coupled plasma optical emission spectrometer (ICP-OES) Was used to measure the residual Ge content P [ppm]. In addition, as a residual metal derived from polymerization catalysts other than Ge, content of Ti and Fe was also measured simultaneously.

前記数式（Ｉ）において、Ａは試料滴定に要した０．１規定の水酸化ナトリウムの量［μＬ］であり、Ｂは空試験に要した０．１規定の水酸化ナトリウムの量［μＬ］であり、ｆは０．１規定の水酸化ナトリウムの力価（無次元数）であり、Ｗは非晶性共重合ポリエステル系樹脂（Ｂ）のサンプル量［ｇ］を示す。 (6) Acid value of amorphous copolymer polyester resin First, a pellet sample of an amorphous copolymer polyester resin was pulverized and dissolved in benzyl alcohol by heating. Next, chloroform was added to the solution, cooled, phenol red indicator was added, and titration was performed with a 0.1 N sodium hydroxide benzyl alcohol solution. The acid value Q [μeq / g NaOH] of the amorphous copolyester resin at this time is determined by the following formula (I).

In the above formula (I), A is the amount of 0.1 N sodium hydroxide required for the sample titration [μL], and B is the amount of 0.1 N sodium hydroxide required for the blank test [μL]. F is the titer (dimensionless number) of 0.1N sodium hydroxide, and W is the sample amount [g] of the amorphous copolyester resin (B).

(7) Number of bumps The raw materials listed in Table 1 were premixed, and film formation was performed from a die set to a lip gap of 0.7 mm by a single screw extruder adjusted to a maximum temperature of 290 ° C. The film was cut and wound up to have a width of 30 mm, a thickness of 110 μm, and a length of 100 m. While unwinding the film from this film roll at an average speed of 70 m / min, it was sandwiched between the thumb and forefinger, and when the fingertip felt uncomfortable, unwinding was stopped. It was determined according to the above definition whether or not the cause of the uncomfortable feeling was a defect contained in the film, and when it was determined to be a defect, the number of the defects was recorded.
This operation was continued until the unwinding amount of the film reached about 100 m, and the number of butts per 1000 cm ³ was determined from the number of detected butts, the thickness of the film, the width of the film, and the length of the unwound film.

(8) Transparency The film produced in (7) was visually confirmed and evaluated for transparency according to the following criteria.
○: There is no cloudiness and the back of the film can be clearly observed.
X: There is cloudiness and the back of the film is unclear.

(9) Comprehensive evaluation The criteria for comprehensive evaluation are as follows.
◯: The product P × Q of the residual Ge content P and the acid value Q of the amorphous copolyester resin is 675 or less, and no flaws and no increase in resin pressure occur in the melt molding process. Moreover, it is excellent in hydrolysis prevention, and the deterioration of material properties is within an allowable range even after wet heat treatment.
X: Since the product of the residual Ge content P and the acid value Q of the amorphous copolyester resin is larger than 675, the generation of blisters and the increase of the resin pressure occur in the melt molding process. Or since there is little content of a carbodiimide type compound, there is no generation | occurrence | production of a nap and a raise of a resin pressure, However It is easy to hydrolyze and the fall of the material characteristic when wet-heat-processing is remarkable.

As is clear from Table 1, the resin composition of the present invention was a resin composition excellent in all of transparency, heat resistance, hydrolysis resistance, and stability during molding (Examples 1 and 2 ). .
In contrast, in the resin compositions of Comparative Examples 1 to 3, the residual Ge content P in the amorphous copolymer polyester resin (B) and the acid value Q of the amorphous copolymer polyester resin (B) The product P × Q greatly exceeded 675. In particular, in Comparative Examples 1 and 2, the number of bumps per 1000 cm ³ exceeded 1, and the stability during molding was insufficient. Furthermore, the resin composition of Comparative Example 3 had a mass average molecular weight after the wet heat test of less than 40% before the test, and the hydrolysis resistance was insufficient.

  Moreover, when Example 1 and Example 2 are compared, although the residual Ti content in the amorphous copolyester-based resin (B) is different by about 10 times, a significant difference is seen in the number of bumps. I understand that there is no. Therefore, when the above results are evaluated as a whole, the residual Ge content in the amorphous copolymerized polyester resin (B) and the amorphous copolymer are required for the stability during molding of the polyester resin composition of the present invention. It can be concluded that the acid value of the polyester resin (B) contributes greatly.

Claims (6)

A resin composition comprising a polyethylene terephthalate resin (A), an amorphous copolyester resin (B) having a glass transition temperature of 80 ° C. or higher, and a carbodiimide compound (C), the total amount of the resin composition With respect to 100% by mass, (A) is 50.0% by mass or more and 98.5% by mass or less, (B) is 1.0% by mass or more and 49.9% by mass or less, and (C) is 0.5% by mass. (B) contains germanium, and the residual germanium (Ge) content P [ppm] in the (B) and the (B) A polyester-based resin composition having a product P × Q of an acid value Q [μeq / g NaOH] of 675 or less.   The glycol component of the amorphous copolyester resin (B) is 3,9-bis (1,1-dimethyl-2-dihydroxyethyl) -2,4,8,10-tetraoxaspiro- (5, 5) -undecane, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, (3S, 3aα, 6aα) -hexahydrofuro [3,2-b] furan-3α, 6β-diol, and The polyester resin composition according to claim 1, comprising one or more selected from the group consisting of tricyclodecane dimethanol.   The polyester resin composition according to claim 1, wherein the carbodiimide compound (C) is an aromatic polycarbodiimide compound.   A polystyrene-converted film obtained by gel permeation chromatography measurement after treating the film obtained by molding the resin composition for 30 hours under conditions of a temperature of 130 ° C., a relative humidity of 85%, and an absolute vapor pressure of about 0.23 MPa. The polyester-based resin composition according to any one of claims 1 to 3, wherein the value of the weight average molecular weight is 40% or more of the value of the weight average molecular weight before the treatment.   The resin molding produced using the polyester-type resin composition of any one of Claim 1 to 4.   The heat-shrinkable resin molded object produced using the polyester-type resin composition of any one of Claim 1 to 4.

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