JP2016069600A - Polyester resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester resin composition which has excellent transparency and flexibility, high heat resistance, and a suppressed bleed out of oligomers, and which prevents sticking between molded articles and between pellets.SOLUTION: The polyester resin composition comprises a polyester resin obtained by polymerizing a dicarboxylic acid component including (a) 75 to 98 mol% of an alicyclic dicarboxylic acid and (b) 2 to 25 mol% of a dimer acid, and a diol component including 75 mol% or more of an alicyclic diol. The (a) alicyclic dicarboxylic acid is preferably an alicyclic dicarboxylic acid having 5 to 30 carbon atoms. Of the (a) alicyclic dicarboxylic acid units contained in the polyester resin composition, a ratio of trans isomers relative to a sum of trans isomers and cis isomers is preferably 80% or more. The (b) dimer acid is preferably a dimer acid having 36 carbon atoms or 44 carbon atoms.SELECTED DRAWING: None

Description

  The present invention relates to a polyester resin composition used for various molding materials, and more specifically, excellent transparency and flexibility, high heat resistance, low oligomer bleed-out, and further between molded products and pellets. The present invention relates to a polyester resin composition that hardly causes sticking.

  Polyesters represented by polyethylene terephthalate (PET) are widely used as materials for bottles and sheets because of their excellent transparency and mechanical properties. The polyester is usually obtained by esterification and / or transesterification of a dicarboxylic acid component and a diol component, and taking out the diol component out of the reaction system under reduced pressure and performing a polycondensation reaction.

  For example, by using a terephthalic acid component and an ethylene glycol component or a 1,4-butanediol component, a homopolymer of PET or polybutylene terephthalate (PBT) can be obtained, respectively, but these monomer components constituting PET and PBT By adding other dicarboxylic acid components and / or diol components, copolymer polyesters having various properties can be obtained. In particular, flexibility can be imparted by copolymerizing polyoxytetramethylene glycol with polyester such as PET and PBT, and when it is made amorphous by copolymerizing another monomer, it resembles a soft vinyl chloride resin. Soft copolyester is obtained (for example, see Patent Documents 1 to 3).

  However, the glass transition temperature (Tg) of such a non-crystallized soft copolymer polyester is often room temperature, that is, 25 ° C. or less. There has been a problem that the oligomer in the resin bleeds out, and a part of the bleed out results in loss of transparency and surface gloss of the molded product. Further, since the heat resistance of the resin is lowered due to the amorphization, as a result, there is a problem that adhesion between molded products or adhesion between pellets before molding easily occurs.

  On the other hand, for example, in Patent Document 4, a polyester resin copolymerized with polyoxytetramethylene glycol is further copolymerized with 5-sodiumsulfoisophthalic acid or a diester derivative component thereof to bleed out oligomers. Has been reported to reduce. However, although the method of Patent Document 4 can obtain a polyester resin with reduced bleed-out over time, it does not solve the problem of sticking between molded products and pellets because of insufficient heat resistance.

Japanese Patent No. 3270185 JP 2000-302888 A JP 2002-363271 A Japanese Patent No. 4764054

  The present invention has been made to solve the above-mentioned problems, and its purpose is excellent in transparency and flexibility, high heat resistance, low oligomer bleed-out, and further between molded products and pellets. An object of the present invention is to provide a polyester resin composition that hardly causes sticking.

  As a result of intensive studies by the present inventors in view of the above-mentioned problems of the prior art, 2 to 25 mol% of dimer acid is copolymerized with respect to polyester mainly composed of alicyclic dicarboxylic acid and alicyclic diol. In addition to maintaining excellent transparency even when crystallized, the polyester resin has excellent flexibility, high heat resistance, and low oligomer bleed-out. It has been found that the resin does not easily cause sticking between the pellets and satisfies all these requirements, and the present invention has been completed.

That is, the polyester resin composition according to the present invention comprises (a) a dicarboxylic acid component containing 75 to 98 mol% of an alicyclic dicarboxylic acid and (b) 2 to 25 mol% of a dimer acid, and (c ) It includes a polyester resin obtained by polymerizing a diol component containing 75 mol% or more of an alicyclic diol.
Moreover, in the said polyester resin composition, it is preferable that (a) alicyclic dicarboxylic acid is C5-C30 alicyclic dicarboxylic acid.
Moreover, in the said polyester resin composition, it is desirable for the ratio of the trans body with respect to the sum total of the trans body and cis body of the (a) alicyclic dicarboxylic acid unit contained in a polyester resin composition to be 80% or more.
Moreover, in the said polyester resin composition, it is preferable that (b) dimer acid is a C36 or C44 dimer acid.

  The polyester resin composition according to the present invention has excellent transparency and flexibility, high heat resistance, low oligomer bleed-out, and hardly causes sticking between molded products and pellets.

Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to these contents unless departing from the gist of the present invention.
The polyester resin composition of the present invention comprises (a) a dicarboxylic acid component containing 75 to 98 mol% of an alicyclic dicarboxylic acid and (b) 2 to 25 mol% of a dimer acid, and (c) an alicyclic ring. It includes a polyester resin obtained by polymerizing a diol component containing 75 mol% or more of a formula diol.

<Dicarboxylic acid component>
(A) Alicyclic dicarboxylic acid (a) The alicyclic dicarboxylic acid is a monocyclic cycloalkane such as cyclopentane, cyclohexane, cycloheptane or cyclooctane, or a bicyclic alkane such as decahydronaphthalene (decalin). It is a compound having a ring structure and two carboxyl groups. Examples of the alicyclic dicarboxylic acid used in the present invention include 1,2-, 1,3-, 1,4-cyclohexanedicarboxylic acid, 1,4-, 1,5-, 2,6-, 2, Examples include 7-decahydronaphthalenedicarboxylic acid. Of these, the use of 1,4-cyclohexanedicarboxylic acid is preferred because the molding temperature of the resulting polyester is close to the conventional molding temperature and is easily available industrially.

  The (a) alicyclic dicarboxylic acid may be an unsubstituted compound or a derivative such as an alkyl ester. Examples of the alkyl ester derivative include alkyl esters having 1 to 10 carbon atoms, more specifically, dimethyl ester, diethyl ester and the like, and dimethyl ester can be particularly preferably used. Although not particularly limited, if an unsubstituted alicyclic dicarboxylic acid is used as a polymerization raw material and polymerized by direct esterification, isomerization from a trans form to a cis form is likely to occur during the polymerization reaction. It becomes difficult to control the ratio of trans isomers contained in the resin to 80% or more. For this reason, it is particularly desirable to use an alkyl ester as the alicyclic dicarboxylic acid.

  In the polyester resin composition of the present invention, the content of (a) alicyclic dicarboxylic acid is 75 to 98 mol% in the total amount of the dicarboxylic acid component. More preferably, it is 80-90 mol% in the total amount of the dicarboxylic acid component. (A) When alicyclic dicarboxylic acid is less than 75 mol%, the crystallization rate of a polymer falls and it is inferior to moldability. In addition, when components other than (a) alicyclic dicarboxylic acid are used as the main component of dicarboxylic acid, for example, when aromatic dicarboxylic acid is used, whitening occurs over time or sufficient transparency cannot be obtained.

  The ratio of the trans isomer to the total of the trans isomer and cis isomer of the (a) alicyclic dicarboxylic acid unit contained in the polyester resin composition of the present invention is preferably 80% or more, and more preferably 90% or more. It is desirable. If the trans isomer ratio is less than 80%, the melting point of the polymer is lowered, the heat resistance is lowered, the balance of crystallinity is lost, and it becomes difficult to maintain transparency after crystallization, so the transparency is poor. Or whitening may occur over time. In addition, although a resin with high heat resistance is obtained as the trans isomer ratio is high, isomerization from a trans isomer to a cis isomer occurs in the polymerization step. For example, a trans isomer ratio exceeding 95% is obtained as a resin after polymerization. That is usually difficult.

  Further, in the (a) alicyclic dicarboxylic acid used as a polymerization raw material, the isomer ratio of the trans isomer and the cis isomer is preferably trans isomer / cis isomer = 90/10 to 100/0, more preferably. 95/5 to 100/0. Considering the isomerization from the trans isomer to the cis isomer in the polymerization step, it is difficult to control the ratio of the trans isomer contained in the resin to 80% or more when the ratio of the trans isomer is less than 90%.

(B) Dimer acid (b) Dimer acid is a dicarboxylic acid compound obtained by dimerization of an unsaturated fatty acid having 10 to 30 carbon atoms, for example, an unsaturated fatty acid having 18 carbon atoms such as oleic acid or linoleic acid. Or a dimerized dicarboxylic acid having 36 or 44 carbon atoms obtained by dimerizing an unsaturated fatty acid having 22 carbon atoms such as erucic acid, or an ester-forming derivative thereof. Dimer acid in which unsaturated double bond remaining after dimerization is saturated by hydrogenation is called hydrogenated dimer acid, and hydrogenated dimer acid is preferably used in terms of reaction stability, flexibility, impact resistance, etc. be able to. In addition, (b) dimer acid is usually obtained as a mixture of a compound having a linear branched structure compound, an alicyclic structure, etc., and although these contents differ depending on the production process, these contents are not particularly limited. .

  In the polyester resin composition of the present invention, the content of (b) dimer acid is 2 to 25 mol% in the total amount of the dicarboxylic acid component. More preferably, it is 10 to 20 mol% in the total amount of the dicarboxylic acid component. (B) When the dimer acid is out of the range of 2 to 25 mol%, the balance of crystallization of the polymer is lost, and it is difficult to obtain high transparency even if it is crystallized. Furthermore, when (b) dimer acid is less than 2 mol%, the flexibility of the polymer is inferior, and when it exceeds 25 mol%, the crystallization rate of the polymer becomes slow, and the moldability tends to be inferior.

In addition, in the polyester resin composition of the present invention, (a) an alicyclic dicarboxylic acid and (b) a dicarboxylic acid component other than dimer acid may be used in an appropriate amount as a polymerization raw material. For example, terephthalic acid, Aromatic dicarboxylic acids such as isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, and succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, And aliphatic dicarboxylic acids such as azelaic acid and sebacic acid. In addition, you may use these dicarboxylic acid components individually or in combination of 2 or more types.

<Diol component>
(C) Alicyclic diol (c) The alicyclic diol is a compound having an alicyclic structure such as a monocyclic cycloalkane and a bicyclic alkane and two hydroxyl groups. For example, 1,2-, 1, 5-membered ring diols such as 3-cyclopentanediol, 1,2-, 1,3-cyclopentanedimethanol, bis (hydroxymethyl) tricyclo [5.2.1.0] decane, 1,2-, 1, 6-membered ring diols such as 3-, 1,4-cyclocyclohexanediol, 1,2-, 1,3-, 1,4-cyclocyclohexanedimethanol, 2,2-bis- (4-hydroxycyclohexyl) -propane Etc. Of these, 1,2-, 1,3-, 1,4-cyclocyclohexanedimethanol is preferred. In particular, 1,4-cyclohexanedimethanol has a methylol group in the para position, high reactivity, and high Since it is easy to obtain polyester having a degree of polymerization, it can be suitably used. 1,4-cyclohexanedimethanol is usually a mixture of a trans isomer and a cis isomer, and the ratio of the trans isomer / cis isomer of 1,4-cyclohexanedimethanol used as a polymerization raw material is particularly limited. Although it is not a thing, it is preferable that it is 80 / 20-60 / 40, More preferably, it is 75 / 25-70 / 30.

  In the polyester resin composition of the present invention, the content of (c) alicyclic diol is 75 mol% or more in the total amount of diol components. More preferably, it is 85 mol% or more in the total amount of the dicarboxylic acid component, and the total amount of the diol component may be (c) an alicyclic diol. (C) When the alicyclic diol is less than 75 mol%, the heat resistance of the polymer is inferior, so that sticking easily occurs between molded products and between pellets, and the crystallization speed becomes slow, so that molding processability is reduced. Inferior to

Other diol components other than (c) alicyclic diols may be used as long as they are in the range of less than 25 mol% in the total amount of other diol components. (C) Examples of diol components other than alicyclic diol include ethylene glycol, propylene glycol, butanediol, hexanediol, octanediol, decanediol, ethylene oxide adducts such as bisphenol A and bisphenol S, and trimethylolpropane. These may be used alone or in combination of two or more.

<Method for producing polyester resin composition>
The method for producing the polyester resin composition of the present invention is not particularly limited, and the polymerization reaction between the dicarboxylic acid component and the diol component can be performed by a known method using a known catalyst. Either a method of directly esterifying an unsubstituted dicarboxylic acid as a starting material, or a method of performing an ester exchange reaction using an esterified product such as dimethyl ester as a starting material may be used, but the unsubstituted (a) alicyclic dicarboxylic acid may be used. In direct esterification using an acid, isomerization from a trans isomer to a cis isomer tends to occur during the polymerization reaction, and it becomes difficult to control the ratio of the trans isomer to 80% or more. It is desirable to conduct a transesterification reaction using an esterified product of a cyclic dicarboxylic acid. More specifically, it is desirable to perform a transesterification reaction and an esterification reaction under a normal pressure using a known catalyst, and then further perform a polymerization reaction under a reduced pressure using a known catalyst.

  In reacting the components (a) to (c) which are polymerization raw materials, the molar ratio of the total diol component / total dicarboxylic acid component in the raw material is within a range of 0.8 to 1.5, and the diol is appropriately selected. It is desirable to use the component in an adjusted amount, more preferably 0.9 to 1.3. When the molar ratio exceeds 1.5, in (a) the alicyclic dicarboxylic acid, isomerization from the trans isomer to the cis isomer tends to occur, and the trans isomer ratio contained in the resin after polymerization becomes low, It may be inferior in heat resistance. On the other hand, when the molar ratio is less than 0.8, the transesterification reaction does not proceed smoothly, the molecular weight of the obtained resin is reduced, and sufficient mechanical properties sufficient for practical use may not be obtained.

  As the catalyst for the transesterification reaction, it is desirable to use at least one kind of metal compound, and preferable metal elements include sodium, potassium, calcium, titanium, lithium, magnesium, manganese, zinc, tin, cobalt and the like. It is done. Of these, titanium and manganese compounds are preferred because of their high reactivity and good color tone of the resulting resin. The usage-amount of a transesterification catalyst is 5-1000 ppm normally with respect to the polyester resin to produce | generate, Preferably it is 10-100 ppm.

  In the transesterification, for example, each component used as a polymerization raw material and other various copolymerization components used as necessary are charged into a reaction vessel equipped with a heating device, a stirrer and a distillation pipe, and a reaction catalyst is added. In addition, the temperature is increased while stirring in an atmospheric pressure inert gas atmosphere, and the reaction is allowed to proceed while distilling off by-products such as methanol produced by the reaction. The reaction temperature is 150 ° C. to 270 ° C., preferably 160 ° C. to 260 ° C., and the reaction time is usually about 3 to 7 hours.

  Further, after the transesterification reaction is completed, it is desirable to add an equimolar or more phosphorus compound and the esterification reaction to further proceed with the esterification reaction. In the present invention, for example, (a) an ester exchange reaction using an alicyclic dicarboxylic acid ester compound and (c) an alicyclic diol is first performed, and then (b) a dimer acid is added together with a phosphorus compound. And it is desirable to manufacture the polyester resin containing each component of (a)-(c) by advancing esterification reaction. Examples of phosphorus compounds include phosphoric acid, phosphorous acid, trimethyl phosphate, triethyl phosphate, tributyl phosphate, trimethyl phosphite, triethyl phosphite, tributyl phosphite and the like. Of these, trimethyl phosphate is particularly preferred. The usage-amount of a phosphorus compound is 5-1000 ppm normally with respect to the polyester resin to produce | generate, Preferably it is 20-100 ppm.

  Further, following the ester exchange reaction and the esterification reaction, a polycondensation reaction is further performed until a desired molecular weight is obtained. As a catalyst for the polycondensation reaction, it is desirable to use at least one metal compound. Preferred metal elements include titanium, germanium, antimony, aluminum and the like. Of these, titanium and germanium compounds are particularly desirable because of their high reactivity and excellent transparency of the resulting resin. The usage-amount of a polymerization catalyst is 30-1000 ppm normally with respect to the polyester resin to produce | generate, Preferably it is 50-500 ppm.

  The polycondensation reaction is performed, for example, after adding the polycondensation catalyst in the reaction vessel containing the products after the above transesterification and esterification reaction, and gradually raising the temperature and reducing the pressure in the reaction vessel. . The pressure in the tank is finally reduced from atmospheric pressure to 0.4 kPa or less, preferably 0.2 kPa or less. The temperature in the tank is raised from 220 to 230 ° C., finally to 250 to 290 ° C., preferably 260 to 270 ° C. After reaching a predetermined torque, the reaction product is extruded from the bottom of the tank and recovered. To do. In the usual case, the reaction product can be extruded into water as a strand, cooled and then cut to obtain a pellet-shaped polyester resin.

  In the polyester resin composition of the present invention, various additives such as an antioxidant, a heat stabilizer, a lubricant, an antistatic agent, a plasticizer, an ultraviolet absorber, and a pigment are appropriately blended depending on applications and molding purposes. Can do. These additive components may be blended in any of the polymerization reaction step and the processing / molding step. Antioxidants include hindered phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, etc., but particularly hindered phenolic antioxidants can be suitably used, and the content Is preferably about 100 to 5000 ppm. Further, when forming a melt-extruded film, a metal salt such as magnesium acetate, calcium acetate, or magnesium chloride may be added to stabilize the positive electrostatic adhesion of the cooling roll.

  The polyester resin composition of the present invention is excellent in flexibility and transparency, high in heat resistance, in addition, bleed-out, sticking between molded products or pellets hardly occurs, and excellent in stability over time and molding processability. Therefore, it can be used in a wide range of molding materials such as electric and electronic parts and automotive materials.

  Hereinafter, the content of the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples without departing from the gist of the present invention. In addition, the method used in each Example and the comparative example is as follows.

(1) Trans body ratio of alicyclic dicarboxylic acid in polyester resin composition 30-50 mg of a polyester resin composition is dissolved in deuterated chloroform containing 50 vol% trifluoroacetic acid, and a 400 MHz 1H-NMR measuring apparatus (Bruker Company) The trans isomer ratio was calculated from the NMR spectrum measured in the above.
(2) Glass transition temperature (Tg), crystallization temperature (Tc) and melting point (Tm)
Each of Tg, Tc, and Tm was determined from a DSC curve measured at a heating rate of 10 ° C./min with a scanning differential calorimeter DSC (manufactured by Perkin Elmer, DSC7) using 10 mg of the polyester resin composition.

(3) Haze Using an injection molding machine (manufactured by Nippon Steel, J150SA), a polyester resin composition plate (thickness 2 mm) was molded under the condition of a resin temperature of 260 ° C., and a haze meter (manufactured by Nippon Denshoku) , NDH4000) to measure haze.
(4) Modulus of elasticity Using an injection molding machine (manufactured by Nippon Steel Works, J150SA), a test piece of polyester resin composition (ISO527-2 compliant, No. 1A) is molded under the condition of a resin temperature of 260 ° C. The elastic modulus was measured using a testing machine (TS Engineering, UCT-2.5T).

(5) Adhesion test under load The pellet of the polyester resin composition was put into a cylindrical container having an inner diameter of 55 mm and a height of 37 mm, a load of 5 kg was applied from above, and the resin was held in an oven heated to 100 ° C. for 3 hours, and then the resin. The appearance and the presence or absence of agglutination were confirmed.
(6) Bleed-out property Using an injection molding machine (manufactured by Nippon Steel Works, J150SA), a polyester resin composition plate (thickness 2 mm) was molded under the condition of a resin temperature of 260 ° C, and in an oven at 60 ° C. After standing for one week, the presence or absence of oligomer precipitation on the plate surface was confirmed.

  The present inventors manufactured polyester resins of the following Examples and Comparative Examples, and evaluated various physical properties using the above methods. Tables 1 and 2 summarize the raw material compositions of the polyester resins of each Example and Comparative Example and the physical property evaluation results of the obtained resins.

<Example 1>
In a reactor equipped with a stirrer, a distillation pipe and a decompressor, (a) dimethyl 1,4-cyclohexanedicarboxylate (DMCD, trans body ratio 98%) 12.90 kg, (c) 1,4-cyclohexanedi Charge 11.47 kg of methanol (CHDM), 0.3 kg of ethylene glycol (EG), and 0.11 kg of 10% EG solution of Mn acetate tetrahydrate, heat to 200 ° C. under nitrogen flow, and then 1 hour to 230 ° C. The temperature increased over time. After the transesterification reaction was carried out for 2 hours, (b) 10.30 kg of erucic acid-derived dimer acid (22 carbon atoms, CRIPOL 1004) and 0.11 kg of trimethyl phosphate 10% EG solution were added to the system. Then, esterification reaction was carried out at 230 ° C. for 1 hour. Subsequently, after adding 300 ppm of germanium dioxide as a polycondensation catalyst and stirring, the pressure is reduced to 133 Pa or less in 1 hour. During this time, the internal temperature is increased from 230 ° C. to 270 ° C., and a predetermined viscosity is obtained under a high vacuum of 133 Pa or less. The polycondensation reaction was carried out with stirring. The obtained polymer was extruded into water in the form of a strand and cut into pellets. The thermal properties, haze, light transmittance, elastic modulus, and composition of the obtained polyester resin were as shown in Table 1.

<Examples 2 to 7>
In addition to changing the polymer composition as shown in Table 1, the pelletized polymers of Examples 2 to 7 were produced in the same manner as in Example 1, and various physical properties of the obtained polymers were evaluated.

<Comparative Example 1>
8.86 kg of an oligomer having a molar ratio of ethylene glycol to terephthalic acid of 1.10 was charged into a reactor equipped with a stirrer, a distillation pipe and a decompression device, and dissolved while raising the internal temperature to 240 ° C. . Subsequently, 1.46 kg of 1,4-cyclohexanedimethanol and 0.01 kg of trimethylolpropane were added, the temperature was raised to an internal temperature of 250 ° C., and the mixture was stirred as it was for 60 minutes. 2.79 kg of polyoxytetramethylene glycol having a number average molecular weight of 1000, and 0.3 kg of tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4-hydroxyphenyl) propionate] methane as a heat stabilizer are added. did. After reaching an internal temperature of 250 ° C., 300 ppm of germanium dioxide as a polymerization catalyst and 60 ppm of triethyl phosphate as a phosphorus element were added. After stirring, the pressure was reduced to 133 Pa or less in 1 hour, and the internal temperature was raised to 260 ° C. during this time. After a polycondensation reaction was performed by stirring under a high vacuum of 133 Pa or less until a predetermined viscosity was obtained, the polymer was extruded into water in a manner from the base and cut with a pelletizer to obtain a pellet-shaped polymer. The physical properties of the obtained polyester resin were evaluated in the same manner as in Example 1.

<Comparative Examples 2-7>
In addition to changing the polymer composition as shown in Table 2, in the same manner as in Comparative Example 1, pelletized polymers of Comparative Examples 2 to 7 were produced, and various physical properties of the obtained polymers were evaluated.

  As shown in Table 1, as the dicarboxylic acid component, (a) dimethyl 1,4-cyclohexanedicarboxylate is 76 to 92 mol%, (b) erucic acid-derived dimer acid (carbon number 44) is 24 to 8 mol%, diol The polyester resins of Examples 1 to 4 produced using (c) 1,4-cyclohexanedimethanol as a component are excellent in heat resistance (Tg, Tc, Tm), and have transparency (haze) and flexibility (tensile). (Elastic modulus) is also good, no sticking occurs after applying load and heat, transparency of appearance is kept good despite crystallization, and further maintained at 60 ° C for one week The oligomer bleedout did not occur at all. (C) Polyester resin of Example 5 using 20 mol% of ethylene glycol in addition to cyclohexanedimethanol as the diol component, (b) Example 6 using dimer acid (36 carbon atoms) derived from oleic acid as the dimer acid Also in this polyester resin, as in Examples 1 to 4, good results were obtained in any evaluation. In addition, in the polyester resin of Example 7 in which the polymerization raw material (a) 1,4-cyclohexanedicarboxylic acid (DMCD) was changed and the trans isomer ratio after polymerization was set to 75.2%, the resin appearance was determined in the adhesion test under load. However, the other evaluations were good, although the transparency with time tended to be slightly inferior.

  On the other hand, as shown in Table 2, the soft polyester resin of Comparative Example 1 composed of a PET resin copolymerized with cyclohexanedimethanol or polyoxytetramethylene glycol has a low Tg, so that the oligomer bleed out over time. In addition to being generated, it was amorphous, causing pellet sticking under load. In the soft polyester resin of Comparative Example 2 copolymerized by adding a sodium sulfoisophthalic acid derivative to the polyester composition of Comparative Example 1, the oligomer bleed-out was prevented, but the pellets still stuck under load. It has occurred.

In addition, the polyester resin of Comparative Example 3 using aromatic dicarboxylic acid (terephthalic acid) and (b) dimer acid as the dicarboxylic acid component had a slight whitening due to crystallization in the under-load adhesion test. In the polyester resin of Comparative Example 4 using only aliphatic glycol (1,4-butanediol) as the diol component, whitening occurred due to crystallization immediately after extrusion, and sufficient transparency (haze) was not obtained. (B) The polyester resin of Comparative Example 5 having a dimer acid content of 1 mol% is too hard and insufficient in flexibility (tensile modulus), and in addition, is whitened in an underload test. It has occurred. On the other hand, the polyester resin of Comparative Example 6 in which (b) the dimer acid content was 28 mol% had insufficient transparency (haze). Further, the polyester resin of Comparative Example 7 using 60 mol% of 1,4-cyclohexanedimethanol and 40 mol% of ethylene glycol as the diol component cannot form a test piece, and is further stuck under load. In the test, pellet sticking occurred.

Claims (4)

A dicarboxylic acid component containing (a) 75 to 98 mol% of an alicyclic dicarboxylic acid, and (b) 2 to 25 mol% of a dimer acid;
(C) A polyester resin composition comprising a polyester resin obtained by polymerizing a diol component containing 75 mol% or more of an alicyclic diol.   (A) The alicyclic dicarboxylic acid is a C5-C30 alicyclic dicarboxylic acid, The polyester resin composition of Claim 1 characterized by the above-mentioned.   The polyester according to claim 1 or 2, wherein the ratio of the trans form to the total of the trans form and the cis form of the (a) alicyclic dicarboxylic acid unit contained in the polyester resin composition is 80% or more. Resin composition.   The polyester resin composition according to any one of claims 1 to 3, wherein (b) the dimer acid is a dimer acid having 36 or 44 carbon atoms.