JP5092574B2 - Method for producing copolymer polyester resin - Google Patents

Description

  The present invention relates to a method for producing a copolyester resin, and in particular, relates to a method for producing a copolyester resin that can provide a remarkable effect in preventing adhesion of resin pellets during crystallization treatment and subsequent heat treatment.

  Polyester resins typified by polyethylene terephthalate resin (hereinafter sometimes referred to as PET resin) have excellent mechanical properties, heat resistance, and chemical resistance, so they can be used in a wide range of fields such as fibers, bottles, films, and sheets. It is used. In recent years, attempts have been made to use PET resin as an extrusion-molded product such as a corrugated plate or tube, or as an injection-molded product such as a cosmetic container, beer glass, or daily goods.

However, PET resin has high crystallinity, and when processed into a thick molded product, the inside of the molded product is insufficiently cooled, causing white turbidity due to crystallization, and the transparency is significantly reduced. Therefore, as a method for improving the transparency of the PET resin, an attempt has been made to reduce the crystallinity of the PET resin by adding a copolymer component such as isophthalic acid and to increase the transparency of the molded product.
However, such a copolymerized polyester resin can achieve improvement in transparency of a molded product due to a decrease in crystallinity. However, the crystallization treatment required for producing the copolymerized polyester resin, followed by drying, solidification, and the like. In the phase polymerization step and the like, there is a problem that the resin pellets are strongly fixed to each other, and the productivity is remarkably lowered.

  As a method for preventing sticking between pellets in a heat treatment step such as a crystallization treatment of PET resin pellets, a method of applying mechanical impact to the resin pellets to provide unevenness on the pellet surface, or a method of promoting crystallization of the pellet surface by shearing treatment Etc. have been proposed. For example, a method of applying a shearing process to a PET resin pellet so as to have a specific surface roughness (Ra) to prevent fusion at the time of subsequent solid phase polymerization (see Patent Document 1), A method for preventing sticking by applying a shearing process so as to form surface irregularities in a specific range (see Patent Document 2), and further evaluating the crystallinity of the PET resin pellets by Raman spectroscopy, There has been proposed a method for preventing sticking by applying a shearing treatment so that the half-value width of the carbonyl peak is not more than a specific value.

However, the PET resin which is intended to prevent sticking in Patent Documents 1 to 3 contains almost no copolymer component such as polyethylene terephthalate or polybutylene terephthalate, and the copolymer polyester has a copolymer component of 5 mol% or more. On the other hand, the inventors have found that the methods described in these patent documents are not necessarily effective in preventing the sticking of the pellets.
Japanese Patent No. 3061424 Japanese Patent No. 2935132 Japanese Patent No. 3475709

  In view of the above-mentioned problems of the prior art, an object of the present invention is to provide copolymer polyester resin pellets in which adhesion between resin pellets is reduced in heat treatment steps such as crystallization treatment and drying treatment.

  As a result of intensive studies, the present inventors have performed a shearing treatment so that the copolyester resin pellets have a specific brightness difference before and after the shearing treatment, and after the shearing treatment, heated in a fluid state to perform a crystallization treatment. Thus, it was found that an excellent anti-adhesion effect was obtained, and the present invention was completed.

That is, the gist of the present invention is a reaction for obtaining copolymer polyester resin pellets by reacting a dicarboxylic acid component mainly composed of terephthalic acid and / or an ester-forming derivative thereof with a diol component mainly composed of ethylene glycol. And a shearing step for subjecting the obtained copolymerized polyester resin pellets to a shearing treatment, and the copolymerized polyester resin pellets after the shearing treatment, in a state where the pellets flow, the glass transition temperature of the copolymerized polyester resin or higher and lower than the melting point A method for producing a copolyester resin comprising a crystallization treatment step in which a crystallization treatment is carried out by heating to a temperature of 1, which satisfies the following a) and b): Method.
a) The total of residues derived from dicarboxylic acid components other than terephthalic acid in the copolymerized polyester and residues derived from diol components other than ethylene glycol is 5 to 5 based on residues derived from all dicarboxylic acid components. 20 mol%.
b) The difference (L1-L0) between the lightness L0 of the copolymerized polyester resin pellets before the shearing treatment and the lightness L1 of the copolymerized polyester resin pellets after the shearing treatment satisfies the following formula (1).
0.3 ≦ L1−L0 ≦ 10.0 (1)

In the present invention, the density of the copolyester resin pellets after the crystallization treatment is 1.340 g / cm ³ or more and 1.400 g / cm ³ or less, and the intrinsic viscosity IV 0 of the copolyester resin before the crystallization treatment. It is preferable to perform the crystallization treatment so that the difference (IV1-IV0) from the intrinsic viscosity IV1 of the copolymerized polyester resin after the crystallization treatment exceeds 0 dL / g and is 0.01 dL / g or less.

  According to the method for producing a copolyester resin of the present invention, it is possible to effectively prevent fixation between pellets in a heat treatment step such as crystallization treatment and subsequent solid phase polymerization, drying treatment for molding, Productivity is remarkably improved compared with the conventional method.

  Hereinafter, embodiments of the method for producing a copolyester resin of the present invention will be described in detail.

The method for producing a copolyester resin of the present invention comprises a dicarboxylic acid component mainly composed of terephthalic acid (hereinafter sometimes referred to as “TPA”) and / or an ester-forming derivative thereof, and ethylene glycol (hereinafter referred to as “EG”). A reaction step of obtaining a copolymerized polyester resin pellet by reacting with a diol component having a main component), a shearing step of subjecting the obtained copolymerized polyester resin pellet to a shearing treatment, and after the shearing treatment A copolyester resin comprising: a copolyester resin pellet, wherein the copolyester resin pellet is heated to a temperature not lower than the glass transition temperature and lower than the melting point of the copolyester resin while the pellet is flowing, The method satisfies the following a) and b).
a) The total of residues derived from dicarboxylic acid components other than terephthalic acid in the copolymerized polyester and residues derived from diol components other than ethylene glycol is 5 to 5 based on residues derived from all dicarboxylic acid components. 20 mol%.
b) The difference (L1-L0) between the lightness L0 of the pellet before shearing and the lightness L1 of the copolymerized polyester resin pellet after shearing satisfies the following formula (1).
0.3 ≦ L1−L0 ≦ 10.0 (1)

  The production of the copolyester resin in the present invention is basically not limited except that the polyester resin pellets obtained by the reaction are sheared under predetermined conditions and then crystallized in a fluid state. For example, It can be carried out by a conventional method for producing a polyester resin in which a dicarboxylic acid component containing TPA and / or an ester-forming derivative thereof as a main component and a diol component containing EG as a main component are reacted.

  In this invention, the sum total of the residue derived from dicarboxylic acid components other than TPA and the residue derived from diol components other than EG of the copolyester resin to be produced is 5 with respect to the residues derived from all dicarboxylic acid components. ~ 20 mol%. The lower limit of the copolymer component ratio is preferably 10 mol% or more, and the upper limit is preferably 17 mol%.

  Residues derived from TPA, which is the main component of the dicarboxylic acid component, in the obtained copolyester resin are 80 mol% or more, preferably 85 mol% or more, based on all dicarboxylic acid-derived residues. Moreover, the residue derived from EG which is the main component of a diol component is 80 mol% or more with respect to the residue derived from all the diol components, Preferably it is 85 mol% or more. When the ratio of the main component is less than the above lower limit, when the copolymer polyester resin is molded, the transparency of the molded product is lowered. When the main component ratio exceeds the above upper limit, the crystallinity is remarkably lowered, and thus the effect of preventing the sticking of the pellets in the crystallization process is hardly exhibited.

  Examples of dicarboxylic acid components other than TPA and its ester-forming derivatives used in the reaction include aromatic dicarboxylic acids such as isophthalic acid and naphthalenedicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid and sebacic acid, cyclohexanedicarboxylic acid, etc. And alicyclic dicarboxylic acids, and ester-forming derivatives thereof. These may be used alone or in combination of two or more. Among these dicarboxylic acid components, isophthalic acid and / or ester-forming derivatives thereof are preferable because they can be produced industrially at low cost.

  Examples of diol components other than EG include alicyclic diols such as 1,4-cyclohexanediol, and aliphatic diols such as diethylene glycol and 1,4-butanediol. Among these, 1,4-cyclohexanedimethanol is preferable because a copolyester resin excellent in impact resistance can be obtained.

[Reaction process]
The reaction method in the reaction step is to esterify a dicarboxylic acid component having TPA as a main component and a diol component having EG as a main component in an esterification reaction tank, and subject the resulting esterification reaction product to a polycondensation reaction. A direct polymerization method in which a polycondensation is carried out by transfer to a tank, a dicarboxylic acid component mainly composed of an ester-forming derivative of TPA and a diol component mainly composed of EG are subjected to a transesterification reaction in a transesterification reaction tank. There is a transesterification method in which a transesterification product is transferred to a polycondensation reaction tank and polycondensed.
These reactions may be performed by a batch method or a continuous method.

The esterification reaction is carried out at a temperature of about 200 to 270 ° C. using an esterification catalyst such as diantimony trioxide, an organic acid salt of a metal such as antimony, titanium, magnesium, calcium, or an alcoholate, if necessary. The transesterification is performed at a temperature of about 1 × 10 ⁵ to 4 × 10 ⁵ Pa, and the transesterification reaction is, for example, an organic acid salt of a metal such as lithium, sodium, potassium, magnesium, calcium, manganese, titanium, and zinc. The transesterification catalyst is used at a temperature of about 200 to 270 ° C. and a pressure of about 1 × 10 ⁵ to 4 × 10 ⁵ Pa.

  In addition, the polycondensation reaction uses, for example, phosphorus compounds such as orthophosphoric acid, phosphorous acid, and esters thereof as a stabilizer, and oxidation of metals such as antimony trioxide, germanium dioxide, and germanium tetroxide. Or an organic acid salt such as antimony, germanium, zinc, titanium, cobalt, etc., and a polycondensation catalyst such as alcoholate, and the like, at a temperature of about 240 to 290 ° C. and a reduced pressure of about 10 to 2000 Pa.

  Usually, the resin obtained by the polycondensation reaction is extracted in the form of a strand from an outlet provided after the bottom of the polycondensation reaction tank, and is cut with a cutter while being cooled with water or after being cooled with water, to be pelletized. The size of the pellet is not particularly limited as long as the effect of the present invention is not hindered, and usually a pellet smaller than about several mm can be used.

[Shearing process]
In the present invention, the surface of the pellet is roughened by subjecting the copolymerized polyester resin pellet obtained as described above to a shearing treatment.

  There is no restriction | limiting in particular as a shearing method of the copolyester resin pellet of this invention, It can carry out using a well-known shearing apparatus. Generally, it is carried out by stirring the resin pellets using a rice mill, a Henschel mixer, a V blender, a ribbon blender, a tumbler blender or the like so that the resin pellets rub against each other. There is no restriction | limiting in particular about the temperature at the time of this shearing process, Usually, it implements at room temperature (about 20-40 degreeC).

  In the present invention, the brightness of the copolymer polyester resin pellet before shearing treatment is L0, the brightness of the copolymerized polyester resin pellet after shearing treatment is L1, and the brightness difference (L1-L0) is 0.3 or more and 10.0 or less. The shearing treatment is performed so that it is preferably 2.0 or more and 10.0 or less, more preferably 2.0 or more and 5.0 or less. If the brightness difference is less than 0.3, it is difficult to obtain the effect of preventing adhesion between the resin pellets in the subsequent crystallization treatment step, and if it exceeds 10.0, the effect of preventing adhesion is saturated, and shavings are generated when shearing is performed. There is a problem that a large amount of (dust) is generated.

  The brightness of the copolymerized polyester resin pellet can be measured by the method described in the Examples section below.

[Crystallizing treatment]
The copolymerized polyester resin pellets after the shearing treatment are then crystallized by heating to a predetermined temperature in a state where the pellets are fluidized.

  The copolyester resin pellets subjected to the shearing treatment under the above-described conditions have less sticking between the pellets in the heat treatment step such as crystallization treatment, and the effect is particularly remarkable when the crystallization treatment is performed in a state where the pellets flow. In the case where the pellets are subjected to heat treatment in a stationary state such as a hopper dryer and in a state where the pellets are subjected to their own weight, it is difficult to obtain the sticking prevention effect of the present invention.

  Examples of the method for heat crystallization treatment in a state where the pellets flow include a method using an indirect heating dryer, a container rotary vacuum dryer, a fluidized bed dryer, and the like. Among these apparatuses, indirect heating type dryers are preferable, and specific examples include commercially available apparatuses such as solid air (manufactured by Hosokawa Micron) and torus disc (manufactured by Hosokawa Micron). By using these apparatuses, the heat treatment time in the crystallization process is shortened, and crystallization can be performed efficiently.

  The crystallization treatment is usually carried out by heating for 1 minute or more in an inert gas atmosphere such as nitrogen gas at a temperature not lower than the glass transition temperature and lower than the melting point of the copolyester resin. It is preferable that it is a temperature range, and it is more preferable that it is a temperature range of 120-160 degreeC. If the temperature during the crystallization treatment is too low, sufficient crystallization is difficult to occur, and if it is too high, fusion between the resins may occur.

  In the crystallization treatment according to the present invention, the copolymer polyester resin pellets after the shearing treatment have a difference (IV1−IV0) between the intrinsic viscosity IV0 before the crystallization treatment and the intrinsic viscosity IV1 after the crystallization treatment of 0 dL / g. It is preferable to heat-treat so that it will be over 0.01 and below 0.01.

Furthermore, in the crystallization treatment according to the present invention, the crystallization treatment may be performed so that the density of the copolyester resin pellets after the crystallization treatment is 1.340 g / cm ³ or more and 1.400 g / cm ³ or less. preferable.

  By adjusting the crystallization treatment temperature and treatment time so that the intrinsic viscosity and density before and after the crystallization treatment are within the above ranges, it is possible to more reliably prevent the pellets from sticking to each other during the crystallization treatment. become able to.

  The copolymerized polyester resin pellets after such crystallization treatment can be heat-treated and solid-phase polymerized to further increase the degree of polymerization, and to reduce acetaldehyde, low-molecular oligomers, and the like as reaction by-products. .

  Thus, the copolyester resin pellets obtained by the shearing and crystallization treatments according to the present invention are firmly fixed when heated, such as subsequent solid-phase polymerization or heat drying when molding them. Hard to happen.

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to the following examples unless it exceeds the gist.
Various analysis methods and evaluation methods for polyester resins are as follows.

(1) Copolymer composition
Polyester resin is dissolved in a mixed solution of phenol / tetrachloroethane = 50/50 (weight ratio), ¹ H-NMR is measured using “AV400M spectrometer” manufactured by BRUKER, and all dicarboxylic acids in the obtained chart The copolymer composition (mol%) for all dicarboxylic acid components was calculated from the peak integrated intensity of the protons of the components and the peak integrated intensity of the protons of each copolymer component. The “prepared base copolymer composition” in Table 1 is a value calculated from the weight of each component actually charged in a glass container in the production of the copolyester resin.

(2) Intrinsic viscosity (IV)
After dissolving about 0.25 g of a polyester resin sample in about 25 mL of a mixture of phenol / 1,1,2,2-tetrachloroethane (weight ratio 1/1) so that the concentration is 1.00 g / dL Then, the sample solution and the solvent were measured by using a fully automatic solution viscometer (“2CH DT504” manufactured by Chuo Rika Co., Ltd.), and the number of seconds dropped only for the sample solution and the solvent was measured and calculated according to the following formula.
IV = ((1 + 4K _H · ηsp) ^0.5 −1) / (2K _H · C)
Here, a ηsp = η / η0-1, η is falling seconds of the sample solution, .eta.0 the falling seconds of the solvent alone, C is a sample solution concentration (g / dL), is K _H is a constant of Huggins . K _H adopted the 0.33. The sample is dissolved at 110 ° C. for 30 minutes.
After shearing the polyester resin pellets, the intrinsic viscosity IV0 before the crystallization treatment and the intrinsic viscosity IV1 after the crystallization treatment were measured, and the difference (IV1-IV0) was calculated.

(3) Transparency (haze)
Polyester resin pellets in a hot-air dryer (“Inert Oven IPHH-201” manufactured by Espec Corp.) at 130 ° C. for 5 hours (however, in the case of an amorphous resin (resins obtained in Examples 8, 10 and 2)) Was dried at 60 ° C. for 5 hours, and the resin moisture content was adjusted to 100 ppm or less, and then an injection molding machine (“M-70AII-DM” manufactured by Meiki Seisakusho Co., Ltd.) was used for injection pressure 60 MPa, molding temperature 260 ° C. A flat plate having a size of 80 mm × 120 mm and a thickness of 5 mm was molded at a mold temperature of 40 ° C. The moisture content was measured by Karl Fischer moisture measurement using “Vaporizer VA-06, MOISTUREMETER CA-06” manufactured by Mitsubishi Chemical Corporation. The measurement conditions at that time were a temperature of 230 ° C. and a nitrogen flow rate of 200 ml / min. The electrolyte used was an anode side: “AQUAMICRON AX” manufactured by Mitsubishi Chemical Corporation, and a cathode side: “AQUAMICRON CXU” manufactured by Mitsubishi Chemical Corporation.
About the obtained plate, haze (haze value) was measured with the haze meter (Nippon Denshoku Co., Ltd. "Haze meter 300A") according to JISK7105 "Optical characteristic test method of plastics". When the haze is 1.0% or less, the molded article has good transparency.

(4) Lightness (L)
Polyester resin pellets are filled into a cylindrical powder colorimetric cell having an inner diameter of 36 mm and a depth of 15 mm, and a colorimetric color difference meter (“ND-300A” manufactured by Nippon Denshoku Industries Co., Ltd.) is used as a reference for JIS Z8730. The color coordinate axis L value of Hunter's color difference formula in the Lab color system described in No. 1 was determined as a simple average value of values measured at four points by rotating the measurement cell by 90 degrees by the reflection method.
The lightness L0 of the pellet before the shearing treatment and the lightness L1 of the pellet after the shearing treatment were measured, and the difference ΔL (= L1−L0) was calculated.

(5) Density In the same manner as the pretreatment at the time of measuring transparency (haze), the polyester resin pellets were dried with hot air to make the resin moisture content 100 ppm or less, and then the pellets 6 to 7 g had an inner diameter of 18.5 mm and a depth of 39. The sample was filled in a cylindrical cell of .5 mm, and measured under an atmosphere of 23 ° C. using an “ACUBIC 1330 density measuring device, Micromeritics pressure control device and REGULATORDR-611A-1 temperature control device” manufactured by Shimadzu Corporation.

(6) Surface roughness (Ra)
The surface roughness of the polyester resin pellets was determined by the method described in JIS B 0601-1994. For the measurement, a surface roughness meter (“Surfcom 1800D” manufactured by Tokyo Seimitsu Co., Ltd.) was used, and measurement was performed in a constant temperature and humidity room at 20 ° C. and 50%. The measurement range was set to 0.75 mm, λc was set to 0.25 mm, and the measured value was obtained as an average value of a total of four locations of two pellets for two pellets.
Ra before the shearing treatment was measured as Ra0 and Ra after the shearing treatment was measured as Ra1, and the difference (Ra1-Ra0) was calculated.

(7) Surface unevenness The surface unevenness of the polyester resin pellets was measured as follows.
First, the polyester resin pellet was embedded using a curable resin. As the curable resin, an epoxy resin (“Epicoat 828” manufactured by JER), a diluent (“RED205” manufactured by JER) and a curing agent (“Epomate B-002W” manufactured by JER) are used in a weight ratio of 80:20:50. What was mixed in the ratio was used. Subsequently, using a microtome (“Microtome TU-213” manufactured by Daiwa Koki Kogyo Co., Ltd.) and a microtome knife (“Microtome Knife 17 cmD manufactured by Daiwa Koki Kogyo Co., Ltd.), a section was cut out so that the pellet cross-section was exposed, and a metal microscope ( Nikon “OPTIPHOT”) and photomicrograph (Nikon “COOLPIX Micro System IV”) are used to photograph and measure the difference between the most convex part and the most concave part per 0.5 mm on the pellet surface. did. The measured value was obtained as an average value at five locations of the same pellet.

(8) Raman analysis The Raman spectrum of the polyester resin was measured using a laser Raman spectrometer (“NRS-2100” manufactured by JASCO Corporation), and the C = O stretch around 1725 cm ⁻¹ under the following measurement conditions on the surface of the pellet. The half width of the vibration peak was measured.
<Polarized microscopic Raman scattering measurement conditions>
Ar laser: 514.5nm line 90-10mW
Micro optical system: Objective lens x 100
Confocal aperture: 25 μm

(9) Glass transition temperature and melting point of resin The glass transition temperature and melting point of the polyester resin pellets were measured by changing only the temperature raising conditions according to the method of JISK7121. Specifically, 7 to 9 mg of polyester resin pellets were sealed in an aluminum standard pan for solids and measured using a differential scanning calorimeter manufactured by METTLER TOLEDO. An empty pan was used as a blank, and the temperature was raised from 30 ° C. to 285 ° C. at a heating rate of 10 ° C./min in a nitrogen atmosphere and held at the same temperature for 5 minutes. After that, it is rapidly cooled to 20 ° C. in a liquid nitrogen atmosphere, and again heated from 20 ° C. to 285 ° C. at a rate of 10 ° C./min. Tmg (midpoint glass transition temperature) as the glass transition temperature and Tpm (melting peak temperature) as the melting point. Each was measured.

[Production of polyester resin]
<Manufacture of isophthalic acid copolyester resin>
Production Example 1
As the dicarboxylic acid component, dimethyl terephthalate (144.6 g, 0.74 mol) and isophthalic acid (hereinafter referred to as “IPA”) dimethyl ester (8.0 g, 0.04 mol), and EG (106 .6 g, 1.72 mol) was charged into a 0.5 L cylindrical glass container and subjected to a transesterification reaction. The charged isophthalic acid composition is 5.2 mol%, and the molar ratio of the diol component to the dicarboxylic acid component is 2.2. In the transesterification reaction, an EG solution of manganese acetate having a concentration of 1.98% by weight was added at 250 ppm by weight with respect to the polyester from which manganese acetate was obtained, and the conditions were 250 ° C., 200 KPa, and the reaction time was 3 hours. went. After the transesterification reaction, an EG solution of germanium dioxide having a concentration of 0.52% by weight is added in an amount of 120 ppm by weight to the polyester from which germanium dioxide is obtained, and an EG solution of orthophosphoric acid having a concentration of 1.50% by weight. Was added in an amount of 300 ppm by weight with respect to the polyester from which orthophosphoric acid was obtained, subjected to a polycondensation reaction at 280 ° C. under a reduced pressure of 66 Pa for 5 hours, extracted into a strand, and cut with a cutter while cooling with water. It was in a pellet form.
Table 1 shows the results obtained by measuring the copolymer composition (mol%), density, glass transition temperature, melting point, intrinsic viscosity (IV0), and lightness L0 for the obtained copolymer polyester resin.

Production Examples 2-4, 9, 10
In Production Example 1, copolymerization was performed in the same manner as in Production Example 1 except that the amount of isophthalic acid dimethyl ester was changed as shown in Table 1 so that the isophthalic acid copolymer composition of the polyester resin was as shown in Table 1. A polyester resin was produced. Various measurement results are shown in Table 1.

<Production of 1,4-cyclohexanedimethanol copolymerized polyester resin>
Production Example 5
Diethyl terephthalate (150.5 g, 0.76 mol) as a dicarboxylic acid component, EG (100.6 g, 1.62 mol) and 1,4-cyclohexanedimethanol (hereinafter referred to as “CHDM”) as a diol component ) (7.1 g, 0.05 mol) was charged into a 0.5 L cylindrical glass container and subjected to a transesterification reaction. The charged CHDM composition is 6.5 mol%, and the molar ratio of the diol component to the dicarboxylic acid component is 2.2. In the transesterification reaction, an EG solution of manganese acetate having a concentration of 2.24% by weight was added at 300 ppm by weight with respect to the polyester from which manganese acetate was obtained, and the conditions were 250 ° C., 200 KPa, and the reaction time was 3 hours. went. After the transesterification reaction, an EG solution of germanium dioxide having a concentration of 0.53% by weight is added in an amount of 120 ppm by weight to the polyester from which germanium dioxide is obtained, and an EG solution of orthophosphoric acid having a concentration of 0.73% by weight. Was added in an amount of 240 ppm by weight to the polyester from which orthophosphoric acid was obtained, subjected to a polycondensation reaction at 280 ° C. under a reduced pressure of 66 Pa for 5 hours, extracted into a strand, and cut with a cutter while cooling with water. It was in a pellet form.
Table 1 shows the results obtained by measuring the copolymer composition (mol%), density, glass transition temperature, melting point, intrinsic viscosity (IV0), and lightness L0 for the obtained copolymer polyester resin.

Production Examples 6-8, 11, 12
In Production Example 5, the copolymerized polyester resin was prepared in the same manner as in Production Example 5 except that the amount of CHDM charged was changed to the amount shown in Table 1 so that the CHDM copolymer composition of the polyester resin became the amount shown in Table 1. Manufactured. Various measurement results are shown in Table 1.

  The resins obtained in Production Example 1 to Production Example 12 are shown in Table 1 as Resin 1 to Resin 12, respectively.

[Processing and evaluation of resin pellets]
Examples 1-8
The following treatments and evaluations were performed for the resins 1 to 8 obtained in Production Examples 1 to 8.

<Shearing>
The obtained copolyester resin pellet is calculated as 1 pass (residence time of 20 minutes) at room temperature and at a rotation speed of 100 rpm in solid air (model: SJS-4-1.5 manufactured by Hosokawa Micron). ) And the brightness of the copolymer polyester resin pellets was measured before and after the shearing treatment. Table 2 shows the difference (L1-L0) between the lightness L0 of the pellet before shearing and the lightness L1 of the pellet after shearing.

<Crystallizing treatment>
The copolymerized polyester resin pellets subjected to the shearing treatment were subjected to crystallization treatment in a fluidized bed by the following method. The density of the pellets after the crystallization treatment and the intrinsic viscosities (IV0, IV1) before and after the crystallization treatment were measured, and the intrinsic viscosity differences (IV1-IV0) are shown in Table 2.

1. A cylindrical glass tube having an inner diameter of 30 mm and a height of 350 mm is filled with 10 g of pellets. The glass tube is discharged from the nozzle at the bottom and out of shape so that nitrogen gas can be passed as an inert gas.
2. Nitrogen gas is supplied to the glass tube in an amount of 80 to 90 L / min (converted to normal temperature) so as to rectify in a state where the pellets flow.
3. Crystallization is performed for 60 minutes at a processing temperature of 150 ° C. while immersing a glass tube filled and sealed with pellets in an oil bath heated to a preset temperature and ventilating heated nitrogen gas.
4). After completion of the treatment, the glass tube is taken out from the oil bath, allowed to cool to room temperature, then the pellet is taken out from the glass tube, and the sticking rate is judged and the haze is evaluated.

<Measurement of adhesion rate, haze evaluation>
About the pellet which performed the crystallization process by said method, the sticking rate ((phi)) was calculated | required by the following Formula (2), and it evaluated in accordance with the determination criteria of the following sticking evaluation.
Moreover, haze measurement was performed after shaping | molding about the pellet with a fixation rate of 10% or less. Since the resin having an adhesion rate exceeding 10% is difficult to mold, haze measurement was not performed. The results are shown in Table 2.
Adhesion rate (φ) = weight of adhering matter (*) / total weight × 100 (%) (2)
(* Use two or more fused pellets as fixed matter.)
Judgment criteria for sticking evaluation (each figure shows sticking rate:%)
A: 0 ≦ φ <2.0
○: 2.0 ≦ φ <5.0
Δ: 5.0 ≦ φ ≦ 10.0
×: 10.0 <φ

Comparative Examples 1-4
In Example 1, operation and evaluation similar to Example 1 were performed except having used resin of manufacture examples 9-12. The results are shown in Table 3. Resins 9 and 11 showed an anti-adhesion effect, but the haze after molding was high, and resins 10 and 12 did not show an anti-adhesion effect.

Comparative Examples 5-12
In Examples 1-8, operation and evaluation similar to Examples 1-8 were performed except that no shearing treatment was performed. The results are shown in Table 4.

Comparative Examples 13-18
In Examples 2 to 4 and 6 to 8, the same operation as in Examples 2 to 4 and 6 to 8 except that the solid air condition was 40 rpm (the residence time of one pass was calculated to be 5 minutes). And evaluation. The results are shown in Table 5.

Comparative Examples 19 to 26
In Examples 1 to 8, the crystallization treatment was performed by filling a cylindrical container with an inner diameter of 50 mm and a height of 100 mm with 100 g of the pellet after shearing, placing a weight on the pellet so that a load of 77 kPa was applied, and using a fixed bed. The same operations and evaluations as in Examples 1 to 8 were performed in a hot air dryer (“Inert Oven IPHH-201” manufactured by Espec Corp.) at 150 ° C. for 6 hours in a nitrogen atmosphere. The results are shown in Table 6.

Examples 9 and 10
In Examples 1 and 5, the same operations and evaluations as in Examples 1 and 5 were performed except that the crystallization treatment was performed at 170 ° C. The results are shown in Table 7.

Example 11
In Example 3, the same operation and evaluation as in Example 3 were performed except that the shearing process was performed on Satake “Rice Mill 1PR-7B” in one pass. Moreover, the surface roughness of the pellet, surface unevenness, and evaluation by Raman spectroscopy were performed. The results are shown in Table 8.

Example 12
In Example 3, the same operation as in Example 3 was performed, except that the condition of solid air in the shearing process was 100 rpm (the residence time of one pass was calculated as 10 minutes). Moreover, the surface roughness of the pellet, surface unevenness, and evaluation by Raman spectroscopy were performed. The results are shown in Table 8.

Comparative Example 27
In Example 3, a shearing treatment was performed by filling 20 g of pellets into a glass tube in which a paper file (“# 180 paper file” manufactured by Nagatsuka Kogyo Co., Ltd.) was wrapped around the inner wall, 25 ”), and the same operation and evaluation as in Example 3 were performed except that the treatment was performed at 300 rpm for 50 minutes. Moreover, the surface roughness of the pellet, surface unevenness, and evaluation by Raman spectroscopy were performed. The results are shown in Table 8.

Comparative Example 28
In Example 3, the same operation and evaluation as in Example 3 were performed, except that the shearing treatment was performed by colliding the pellet with the inner wall of the pipe by pneumatic transportation. Moreover, the surface roughness of the pellet, surface unevenness, and evaluation by Raman spectroscopy were performed. The results are shown in Table 8.

From the above results, it can be seen that according to the present invention, it is possible to provide copolymer polyester resin pellets in which adhesion between resin pellets is reduced in a heat treatment step such as crystallization treatment and subsequent drying treatment.
In particular, the following can be seen from the results in Table 8.

The evaluation of the surface roughness (Ra) in Table 8 is based on the method described in Japanese Patent No. 3061424.
Japanese Patent No. 3061424 evaluates the surface roughness (Ra) of the pellets before and after the shearing treatment, and describes that the difference can be expected to have an anti-adhesion effect when Ra 1 −Ra 0 ≧ 0.2 μm. However, from the results of Examples 11 and 12 and Comparative Examples 27 and 28, it was found that Ra1-Ra0 cannot explain the adhesiveness within and outside the range. That is, for example, even when Ra 1 -Ra 0 = 0.17, the sticking is prevented, and even when Ra 1 -Ra 0 = 0.2, the sticking occurs. This is presumably because the object of the present invention is a copolyester resin.

Moreover, the surface unevenness | corrugation height difference of the pellet before and behind a shearing process in Table 8 is based on the method of patent 2935132.
Japanese Patent No. 2935132 evaluates the surface unevenness difference of the pellets after the shearing treatment, and describes that the effect of preventing sticking can be expected when the difference is 1 to 50 μm. However, from the results of Examples 11 and 12 and Comparative Examples 27 and 28, it was found that the adhesiveness could not be explained by the surface unevenness difference within the range. That is, for example, the sticking occurs even when the surface unevenness difference is 3.3 μm. This is presumably because the object of the present invention is a copolyester resin.

Furthermore, the evaluation by the Raman spectroscopy of the pellet surface before and after the shearing treatment in Table 8 is based on the method of Japanese Patent No. 3475709.
In Japanese Patent No. 3475709, the pellet surface before and after the shearing treatment is evaluated by Raman spectroscopy, and the carbonyl peak half-value width is reduced after the shearing treatment. However, in Examples 11 and 12 and Comparative Examples 27 and 28, no change was observed in the half width before and after the shearing treatment. This is presumably because the object of the present invention is a copolyester resin.

  For these reasons, the physical properties and characteristics of the copolymerized polyester resin and the polyester resin that does not contain a copolymerized component are greatly different, so the knowledge of ordinary polyester resins cannot be applied to the copolymerized polyester resin. It can be seen that the resin must have a processing standard for preventing sticking unique to the copolyester resin.

  The copolyester resin produced according to the present invention hardly adheres to pellets in the heat treatment step, has excellent productivity and handleability, and has excellent transparency after being processed into a molded product. It can be suitably used for injection-molded products such as extrusion products such as tubes and tubes, cosmetic containers, beer glasses, and daily goods.

Claims (4)

A reaction step of obtaining a copolymerized polyester resin pellet by reacting a dicarboxylic acid component containing terephthalic acid and / or an ester-forming derivative thereof as a main component with a diol component containing ethylene glycol as a main component, and the resulting copolymerization A shearing process for shearing the polyester resin pellets, and the copolymerized polyester resin pellets after shearing are heated to a temperature above the glass transition temperature and below the melting point of the copolymerized polyester resin in a state where the pellets are flown to crystallize. A method for producing a copolyester resin comprising: a crystallization treatment step for carrying out the treatment, wherein the copolyester resin satisfies the following a) and b).
a) The total of residues derived from dicarboxylic acid components other than terephthalic acid in the copolymerized polyester and residues derived from diol components other than ethylene glycol is 5 to 5 based on residues derived from all dicarboxylic acid components. 20 mol%.
b) The difference (L1-L0) between the lightness L0 of the copolymerized polyester resin pellets before the shearing treatment and the lightness L1 of the copolymerized polyester resin pellets after the shearing treatment satisfies the following formula (1).
0.3 ≦ L1−L0 ≦ 10.0 (1) The density of the copolyester resin pellet after the crystallization treatment is 1.340 g / cm ³ or more and 1.400 g / cm ³ or less, and the intrinsic viscosity IV0 of the copolyester resin before the crystallization treatment, and the crystallization treatment The method for producing a copolyester resin according to claim 1, wherein the difference (IV1-IV0) from the intrinsic viscosity IV1 of the later copolyester resin is more than 0 dL / g and not more than 0.01 dL / g.   The method for producing a copolyester resin according to claim 1 or 2, wherein the dicarboxylic acid component other than terephthalic acid and / or an ester-forming derivative thereof contains isophthalic acid and / or an ester-forming derivative thereof.   The method for producing a copolyester resin according to any one of claims 1 to 3, wherein the diol component other than ethylene glycol contains 1,4-cyclohexanedimethanol.