JP2005220214A - Method for producing polyester composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester composition having improved heat resistance by a rise in glass transition temperature or melting point and remarkably improved thermal or mechanical characteristics such as rigidity, breaking strength or dimensional stability by finely dispersing a new inorganic or organic composite compound into a nanosize in a polyester. <P>SOLUTION: A method for producing the polyester composition is characterized as follows. A specific polyhedral oligometric silsesquioxane (POSS) is added in an optional stage to the completion of polymerization of the polyester when the polyester composed of a bifunctional acid component mainly composed of a dicarboxylic acid and at least one kind of glycol component is produced. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing a polyester composition containing polyhedral oligomeric silsesquioxane (Polyhedral Origometric SilSesquioxane, also called cage silsesquioxane, hereinafter referred to as POSS). More specifically, the present invention relates to a method for producing a polyester composition having improved thermal characteristics such as melting point and glass transition temperature and excellent mechanical characteristics such as rigidity, fracture strength and dimensional stability.

  Polyesters that are industrially produced today, such as polyesters based on polyethylene terephthalate (hereinafter referred to as PET), have excellent physical and chemical properties and are widely used as fibers, films, and other molded articles. in use. It is desired to further improve the properties of fibers, films, and other molded articles by taking advantage of various excellent properties of this polyester.

  By blending and dispersing inorganic fine particles in polyester, it improves slipperiness, abrasion resistance, scratch resistance, etc. in film applications, and also improves matting and see-through prevention and color development, and wear resistance in textile applications. In addition, improvement of physical properties such as compressive strength and tensile strength by mixing in a matrix is also carried out for improvement of mechanical properties and for composite materials. For example, a colloidal silica particle having a linear or branched shape is dispersed in polyester to provide a film excellent in slipperiness, abrasion resistance, and scratch resistance, and a polyester resin suitable for obtaining fibers (Patent Document 1). A method of obtaining polyester fibers suitable for industrial use by adding silicon tetranitride particles or silicon carbide particles having a particle size of 0.3 μm or less to polyester to improve mechanical properties (dimensional stability, heat resistance) (Patent Document 2) ) And a fiber having high toughness and excellent bending wear resistance and bending fatigue resistance by containing a specific amount of solid (silica) fine particles having an average particle size of 0.002 μm or more and 0.50 μm or less in the fiber. Attempts have also been made to obtain (Patent Document 3) and the like.

  In addition to these, many attempts have been made to improve various mechanical properties by blending various inorganic fine particles with polyester, but there are no industrially satisfactory ones yet. This is because the particles themselves used are insufficiently dispersible or agglomerate during the production of the polyester, resulting in the large particle size present in the polyester, which can act on the polymer at the molecular level. It is considered difficult.

  In recent years, attempts have been made to improve the heat resistance and viscoelastic properties of various polymers by applying POSS. For example, POSS is blended with polymers such as polymetamethyl acrylate (PMMA), polypropylene (PP), polyimide (PI), polystyrene (PS), polyurethane (PU), etc., and the heat resistance and viscoelastic properties of each polymer are It has been reported that it can be improved (Non-Patent Document 1).

On the other hand, attempts have been made to apply POSS to polyester (Non-patent Document 2), but the dispersion diameter of POSS in the polyester is several microns or more, and physical properties such as Young's modulus are not improved at all. Is in the situation. Against this background, in order to improve the thermal properties and physical properties of polyester, it has been demanded to finely disperse POSS having a molecular level size into a nano size in the polyester.
Japanese Patent Application Laid-Open No. 05-0778557 JP 07-138812 A Japanese Patent Laid-Open No. 07-011512 Macromolecules vol.29 p7302 Proceedings of the 224th American Chemical Society International Conference POLY191 (2002)

  The object of the present invention is to solve the above-mentioned conventional problems, and finely disperse POSS, which is a novel inorganic / organic composite compound, into a nanosize in polyester, thereby improving the heat resistance by increasing the glass transition point and melting point, An object of the present invention is to provide a method for producing a polyester composition in which thermal and mechanical properties such as fracture strength and dimensional stability are drastically improved.

  In order to solve the above problems, the present inventors have represented the following general formula, and (1) and (1) when producing a polyester comprising a difunctional acid component mainly composed of dicarboxylic acid and at least one glycol component. Polyhedral oligomeric silsesquioxane (POSS) satisfying (2) can be achieved by a method for producing a polyester composition, which is added at any stage until the polymerization of the polyester is completed.

(RSiO _1.5 ) _n (A)
(RSiO _1.5 ) _l (RXSiO) _k (B)
[In the general formulas (A) and (B), R is selected from a hydrogen atom, a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms, or a silicon atom-containing group having 1 to 10 silicon atoms; All may be composed of the same or plural groups. In the general formula (B), X is OR ₁ (R ₁ is a hydrogen atom, an alkyl group, an aryl group, a quaternary ammonium radical), a halogen atom, or at least one functional group selected from R, and (RXSiO ) X in _k may be the same or different. Further, two X in (RXSiO) _k may be connected to each other to form a connection structure represented by the following general formula (C).

Y and Z are selected from the same group of groups as X, and Y and Z may be the same or different. n is an integer of 6 to 14, l is an integer of 2 to 12, and k is 2 or 3. ]
(1) Weight reduction rate at Tp by thermogravimetric analysis is 5% by weight or less (2) Melting point is Tp or less, provided that Tp = Tm + 30 ° C.
Tm = melting point of polyester (° C)

  POSS, a new inorganic / organic composite compound, is finely dispersed in nano-size in polyester to improve heat resistance by increasing the glass transition point and melting point, and to provide thermal and mechanical properties such as rigidity, fracture strength and dimensional stability. A polyester composition having dramatically improved characteristics can be obtained.

  The polyester referred to in the present invention is a polymer formed from an ester bond of a dicarboxylic acid compound and a diol compound. Examples of the dicarboxylic acid compound include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, and diphenyldicarboxylic acid. Aromatic, aliphatic and alicyclic dicarboxylic acids such as acid, adipic acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, 5-sodium sulfoisophthalic acid, 5-tetrabutylfosphonium isophthalic acid and their derivatives Can be mentioned. Examples of the diol compound include ethylene glycol, propylene glycol, butylene glycol, tetramethylene glycol, 1,4-cyclohexanedimethanol, diethylene glycol, neopentyl glycol, polyalkylene glycol, bisphenol A, and bisphenol S, aromatic and aliphatic. And alicyclic diol compounds.

  Polyesters that can be preferably used in the present invention are PET, polyethylene-2,6-naphthalate (hereinafter referred to as 2,6-PEN), polypropylene terephthalate (hereinafter referred to as PPT), and polybutylene terephthalate (hereinafter referred to as PBT). More preferably, it is PET.

  In addition, the polyester used in the present invention may be copolymerized with another third component within a range that does not impair the gist of the invention. Furthermore, the polyester of the present invention may contain a small amount of additives such as matting agents, flame retardants, and lubricants.

POSS in the present invention will be described. Silsesquioxane is also called T-resin, and ordinary silica is represented by the general formula (SiO ₂ ), whereas silsesquioxane is a compound represented by (RSiO _1.5 ) Is a polysiloxane synthesized by hydrolysis-polycondensation of a compound in which one alkoxy group of a tetraalkoxysilane such as tetraethoxysilane is replaced with an alkyl group or an aryl group. There are known amorphous, ladder-like, cage-like (fully condensed cage-like) and fully-condensed cage-like types in which one silicon atom is less, and types in which some silicon-oxygen bonds are broken.

POSS used in the present invention is a cage-like structure of the molecular arrangement or a partially cleaved structure thereof, but silsesquioxane having a closed cage structure has a structure in which a part of the cage is opened. Silsesquioxane may be used. Accordingly, various structures of cage silsesquioxane or partially cleaved structures thereof can be used in the present invention. Specific examples thereof include, for example, the following general formulas (A) and (B): And the compounds shown.
(RSiO _1.5 ) _n (A)
(RSiO _1.5 ) _l (RXSiO) _k (B)
[In the general formulas (A) and (B), R is selected from a hydrogen atom, a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms, or a silicon atom-containing group having 1 to 10 silicon atoms; All may be composed of the same or plural groups. In the general formula (B), X is OR ₁ (R ₁ is a hydrogen atom, an alkyl group, an aryl group, a quaternary ammonium radical), a halogen atom, or at least one functional group selected from R, and (RXSiO ) X in _k may be the same or different. Further, two Xs in (RXSiO) _k may be connected to each other to form a connection structure represented by the general formula (C).

Y and Z are selected from the same group of groups as X, and Y and Z may be the same or different. n is an integer of 6 to 14, l is an integer of 2 to 12, and k is 2 or 3. ]
Specific examples of the cage silsesquioxane represented by the general formula (A) include a type represented by the chemical formula of (RSiO _1.5 ) ₆ (the following formula 3) and a chemical formula of (RSiO _1.5 ) _8. Type (represented by the following formula 4)), a type represented by the chemical formula (RSiO _1.5 ) ₁₀ (the following formula 5), and a type represented by the chemical formula (RSiO _1.5 ) ₁₂ (the following formula 6).

Moreover, the following structures are illustrated as a specific example of the partial cleavage structure of the cage-shaped silsesquioxane represented by general formula (B). For example, a trisilanol body in which a part of the general formula 3 is eliminated or a type represented by a chemical formula of (RSiO _1.5 ) ₄ (RXSiO) ₃ derived therefrom (the following general formula 7: the above trisilanol In the case of X = OH), a partially cleaved structure (RSiO _1.5 ) ₄ (RSiO _1.5 ) _{4 in} which two of the three Xs represented by the general formula 7 are linked by the structure represented by the general formula (C) A type represented by the chemical formula of (RXSiO) ₃ , a disilanol body in which a part of the general formula 3 is cleaved, or a type represented by the chemical formula of (RSiO _1.5 ) ₆ (RXSiO) ₂ derived therefrom (general formula 8 below) : Examples of the disilanol compound include those in the case of X = OH in the general formula 7. R and X or Y and Z bonded to the same silicon atom in the general formulas 7 and 8 may be exchanged in position.

  As R in Chemical Formulas 3 to 8, one type may form a cage silsesquioxane or two or more types of substituents. Specific examples of R include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, octyl group, cyclohexyl group, cyclopentyl group, trifluoropropyl group, phenyl group, trimethylsiloxy group, Diols such as 2-propanediol, amino groups such as aminopropyl groups, epoxy groups such as glycidyl groups, ester groups such as methylpropionate groups, acrylic groups, methacrylic groups, isocyanate groups, vinyl groups, norbonenylethyl groups However, it is not limited to these.

  In the POSS used in the present invention, when the melting point of the polyester is Tm (° C.), the weight reduction rate in the thermogravimetric analysis method at a temperature defined by Tp = Tm + 30 (° C.) is 5% by weight or less. is necessary.

  This is because there is little scattering and deterioration of POSS at the time of addition of the polymer to the polymerization reaction system or at the time of melt molding, and it can be introduced into the polymer at a desired ratio. Since deterioration of various properties can be suppressed, and polyester is generally molded at a high temperature of about melting point + 30 ° C., it is preferable that POSS contained in the polymer has sufficient heat resistance at this temperature.

  From this point of view, 70% or more of R constituting one POSS molecule is one of pentyl group, hexyl group, octyl group, cyclohexyl group, cyclopentyl group, phenyl group, trimethylsiloxy group, norbornenylethyl group. One or two or more POSSs are preferably used.

  Specific examples of POSS include octacyclopentyl POSS, octacyclohexyl POSS, octaphenyl POSS, octatrimethylsiloxy POSS, trisnorbornenylethyl cyclohexyl POSS, trisnorbonenyl ethylcyclopentyl POSS (hereinafter referred to as TNCP-POSS), trisnorbone. Examples thereof include nylethylcycloisobutyl POSS, glycidyl isooctyl POSS (hereinafter referred to as GIO-POSS), and methacrylic isooctyl POSS.

  Further, the melting point of the POSS of the present invention is required to be Tp or less in order to disperse POSS in the molecular level in the polyester, and those having a liquid POSS at the polymer molding temperature are preferably used. Specifically, a cage mixture, which is a mixture of POSS molecules with different numbers of Si, can be cited. However, in the case of a cage mixture, it is difficult for POSS to form a crystal structure and the packing property between molecules. Is lower, the POSS melting point tends to be low, which is more preferable.

  In addition, even in the case of a POSS assembly in which one POSS molecule has a plurality of types of R, or a POSS molecule assembly having different types of R, the packing property between POSSs is reduced, so that crystallization is inhibited. Therefore, the melting point of POSS tends to decrease, which is preferable. Specific examples of the POSS include a cage mixture of isooctyl POSS (hereinafter referred to as IOCG-POSS) and a cage mixture of phenethyl POSS (hereinafter referred to as PECG-POSS).

  In the present invention, the POSS can be added at any stage until the polymerization reaction is completed.

  To explain PET as an example, in general, polymerization of polyester is as follows: (1) A low molecular weight product is obtained by direct esterification reaction using terephthalic acid and ethylene glycol as raw materials, and a high molecular weight polymer is obtained by subsequent polymerization reaction. Process, (2) A low molecular weight product is obtained by transesterification using dimethyl terephthalate and ethylene glycol as raw materials, and then a high molecular weight polymer is obtained by subsequent polymerization reaction.

  The present invention provides an arbitrary stage until the polymerization of the polyester in the series of reactions (1) or (2) is completed, that is, before the esterification reaction starts, during the esterification reaction, after the esterification reaction, or the transesterification reaction. It can be added at any stage before the start, during the transesterification reaction, after the transesterification reaction, and before the completion of the polymerization until the completion of the polymerization. From the viewpoint of operability and dispersibility of POSS in the polyester It is preferable to add it before. In addition, POSS may be dividedly added at an arbitrary stage in these processes.

  The POSS may be added to the polyester reaction system as it is, but the POSS may be mixed in advance with a solvent containing a diol component forming a polyester such as ethylene glycol and added as a solution or slurry.

  Also, a predetermined proportion of polyester and POSS are dissolved in a co-solvent (eg, hexafluoroisopropanol / chloroform mixed solvent) at a temperature of 25 to 50 ° C., and the resulting solution is put into both poor solvents (eg, acetone). Thus, a precipitate may be obtained, and the precipitate from which the solvent is removed may be added.

  The amount of POSS added in the polyester of the present invention is preferably 20% by weight or less. When it is 20% by weight or less, POSS itself does not aggregate in the polyester, dispersibility is good, and it is possible to obtain a polyester having desired thermal and mechanical properties.

  On the other hand, if the POSS content is 1% by weight or more, the amount of POSS molecules acting as a physical cross-linking agent on the polymer molecular chain is sufficient, and the thermal and mechanical properties are improved, and the POSS content is preferably 3% by weight. More preferably, the above is true.

  The reason for improving and improving the thermal and mechanical properties by finely dispersing specific POSS in the polyester is not clear, but the POSS particles refined to the molecular level suppress the molecular motion of the polyester molecular chain. It is thought that. In other words, POSS acts as a so-called physical cross-linking agent that reversibly absorbs and desorbs polyester molecular chains. However, since this action is reversible cross-linking, molding processing such as gelation is different from cross-linking by covalent bonds. It is possible to reduce the mobility of the molecular chain without causing a problem that inhibits the sexiness, and the mobility of the molecule is lowered, so that relaxation during melting is inhibited. As a result, it is estimated that the decrease in entropy contributes to the increase in melting point and the increase in glass transition point and the improvement of Young's modulus due to the decrease in free volume due to the inhibition of molecular motion. Such a cross-linking effect contributes to a reduction in shrinkage and is considered to contribute to an improvement in dimensional stability of the material.

  By improving heat resistance, strength, impact resistance, weather resistance, etc., which are weak points of general-purpose plastics, they are used in advanced technology fields such as automotive parts, mechanical parts of OA equipment, and electrical / electronic materials.

The physical properties of POSS and polyester in the examples were measured by the methods described below. (1) Thermogravimetric (TGA) weight loss rate of POSS Using the following equipment, the change in weight was measured while raising the temperature from room temperature to 450 ° C, and the difference in the respective weight loss rates at 200 ° C and 300 ° C was calculated. Asked.

Apparatus: BRUKER (AXS) TG-DTA 2000S
Condition: Temperature rising rate 10 ° C./min (room temperature to 450 ° C.)
Under N2 (flow rate 50ml / min)
Sample amount: 10mg
(2) POSS average dispersion diameter <Transmission electron microscope observation>
Apparatus: Transmission electron microscope (Hitachi H-7100FA type)
Condition: Acceleration voltage 100kV
Sample preparation: Ultra-thin section method Sample thickness: 50 nm
<Image analysis>
Transmission electron micrographs of each sample were taken into a computer with a scanner. Thereafter, image analysis was performed with dedicated software (Image Pro Plus Ver. 4.0, manufactured by Planetron). By manipulating the tone curve, brightness and contrast are adjusted, and then 100 points of the equivalent circle diameter of the high contrast component of the image obtained using a Gaussian filter are randomly observed, and the average value is taken as the average dispersion diameter. did.

Image processing procedures and parameters:
A. One leveling B. Contrast +30
C. Gauss 1 time Contrast +30, brightness -10
E. Gaussian flattening filter: background (black), object width (20 pix)
Gaussian filter: size (7), strength (10)
(3) POSS content measurement in polyester It dissolves in the solvent (hexafluoroisopropanol / chloroform mixed solution) which melt | dissolves both polyester and POSS, and measures the NMR spectrum of 1H nucleus. From the obtained spectrum, the peak area intensity of absorption peculiar to polyester and POSS is obtained, and the molar ratio of the blend is calculated from the ratio and the number of protons. Further, the weight ratio is calculated from the formula amount corresponding to the unit unit of each polymer.

Equipment: BRUKER DRX-500 (Bruker)
Solvent: Hexafluoroisopropanol / chloroform mixed solution
: 499.8MHz standard
: TMS (0ppm)
Measurement temperature: 30 ° C observation width
: 10KHz data point
: 64K acquisiton time
: 4.952 seconds pulse delay time
: 3.048 seconds integration count
: 256 times (4) Glass transition temperature (Tg), melting point (Tm)
Specific heat was measured with the following equipment and conditions, and determined according to JIS K7121.

Apparatus: Temperature modulation DSC manufactured by TA Instrument
Measurement condition:
Heating temperature: 270-600K (RCS cooling method)
Temperature calibration: Melting point of high purity indium and tin
Temperature modulation amplitude: ± 1K
Temperature modulation period: 60 seconds
Temperature rising step: 5K
Sample weight: 5mg
Sample container: Aluminum open container (22 mg)
Reference container: Aluminum open container (18mg)
In addition, the glass transition temperature here was computed by the following formula.
Glass transition temperature = (extrapolated glass transition start temperature + extrapolated glass transition end temperature) / 2
(5) Intrinsic viscosity [η]
The value calculated by the following formula was used from the solution viscosity measured at 25 ° C. at a concentration of 0.1 g / ml in orthochlorophenol. The unit is indicated by [dl / g].

η _sp / C = [η] + K [η] ² · C
Here, η _sp = (solution viscosity / solvent viscosity) −1, C is the weight of dissolved polymer per 100 ml of solvent (g / 100 ml, usually 1.2), and K is the Huggins constant (assuming 0.343) It is. The solution viscosity and solvent viscosity were measured using an Ostwald viscometer. The unit is indicated by [dl / g].
(6) Bending properties After drying (140 ° C, 5 hours) the polyester resin composition of the present invention, using an injection molding machine with a clamping pressure of 80 t, at a cylinder temperature of 270 to 300 ° C, a thickness of about 6.4 mm, A test piece having a width of about 12.7 mm and a length of about 127 mm was produced. The bending properties of the resulting specimen were measured according to ASTM D-790.
(7) Warping After drying the polyester resin composition of the present invention (140 ° C., 5 hours), using an injection molding machine with a clamping pressure of 80 t, at a mold temperature of 120 ° C. and a cylinder temperature of 270 to 300 ° C., dimensions A flat test piece of about 120 × 120 × 1 mm was produced. Place the above-mentioned flat test piece on a flat surface, press one of the four corners of the test piece, and measure the maximum distance from the flat surface using the gap gauge or caliper. . Each of the four corners was pressed and the average value of the obtained warp values was determined. The smaller the warp value, the better.

  Hereinafter, the present invention will be described specifically and in detail by way of examples. However, the present invention is not limited to the following examples.

Example 1
An esterification reaction tank in which about 1.2 kg of bis (hydroxyethyl) terephthalate was previously charged in a slurry of 1 kg of high-purity terephthalic acid and 0.45 kg of ethylene glycol, and maintained at a temperature of 250 ° C. and a pressure of 1.2 × 10 ⁵ Pa. The mixture was successively supplied over 3.5 hours, and after the completion of the supply, an esterification reaction was carried out over an additional hour, and 1.07 kg of the esterification reaction product was transferred to a polycondensation tank. Subsequently, 53 g of PECG-POSS (5.0% by weight based on the produced polymer) was added to the polycondensation reaction tank to which the esterification reaction product had been transferred, stirred for 10 minutes, and then used as a polycondensation catalyst. Antimony trioxide (0.028% by weight with respect to the resulting polymer) was added. Thereafter, while stirring the low polymer at 48 rpm, the reaction system was gradually heated from 250 ° C. to 290 ° C. and the pressure was reduced to 40 Pa. The time to reach the final temperature and final pressure was both 60 minutes. When the predetermined stirring torque was reached, the reaction system was purged with nitrogen, returned to normal pressure, the polycondensation reaction was stopped, discharged into cold water in a strand form, and immediately cut to obtain pellets. The time from the start of decompression to the arrival of the predetermined stirring torque (polymerization time) was 2 hours 50 minutes. The obtained polyester pellets had an intrinsic viscosity of 0.70 and a POSS content of 4.7% by weight. The dispersibility of POSS was good, and the average dispersion diameter was 24 nm.

  Table 1 shows the results of preparing test pieces using the PECG-POSS-containing resin pellets and evaluating the bending characteristics and warpage. It had a glass transition temperature of 88 ° C. and a melting point of 260 ° C., and had excellent performance in bending elastic modulus, bending strength, and warpage characteristics.

Examples 2-5
It carried out similarly to Example 1 except having changed the addition amount of PECG-POSS. The dispersion of POSS in the polyester was good, and the average particle size was 1 μm (1000 nm) or less.

  Table 1 shows the results of preparing test pieces and evaluating the bending characteristics and warpage. All of them were suitable for thermal characteristics, and had excellent performance in bending elastic modulus, bending strength and warpage characteristics.

Examples 6-8
The same procedure as in Example 1 was performed except that the type of POSS was changed, but the dispersibility of POSS was good at any level.

Table 1 shows the results of preparing test pieces and evaluating the bending characteristics and warpage. Comparative Examples 1 and 2 in which the thermal characteristics were improved at any level and the bending elastic modulus, bending strength, and warpage characteristics were excellent.
The same procedure as in Example 1 was performed except that another POSS defined in the present invention was used. The dispersibility of POSS was poor, and the average dispersion diameter was 1 μm (1000 nm) or more.

  Table 1 shows the results of making test pieces using the POSS-containing PET resin pellets and evaluating the bending characteristics and warpage. Neither glass transition temperature nor melting point was improved in thermal properties, and the flexural modulus, flexural strength and warpage properties were inferior.

Comparative Example 3
The same procedure as in Example 1 was performed except that PECG-POSS was not added.

  Table 1 shows the results of preparing test pieces using the POSS-free PET resin pellets and evaluating the bending characteristics and warpage. The bending elastic modulus, bending strength and warpage characteristics were inferior.

Example 9
A reactor was charged with 1 kg of dimethyl 2,6-naphthalenedicarboxylate, 0.55 kg of ethylene glycol, 0.30 g of manganese acetate tetrahydrate and 0.08 g of cobalt acetate tetrahydrate, and heated. The temperature inside the can was gradually raised to 180 to 230 ° C. together with the distillation of methanol, and the transesterification reaction was terminated when the distillation of methanol almost disappeared, and the entire reaction product was transferred to a polycondensation tank. Subsequently, PECG-POSS (5.0 wt% with respect to the produced polymer) was added to the reaction system to which the reaction product had been transferred and stirred for 10 minutes. Antimony oxide (0.02% by weight based on the resulting polymer) was added. Thereafter, while stirring the low polymer at 48 rpm, the reaction system was gradually heated from 230 ° C. to 290 ° C. and the pressure was reduced to 35 Pa. The time to reach the final temperature and final pressure was both 60 minutes. When the predetermined stirring torque was reached, the reaction system was purged with nitrogen, returned to normal pressure, the polycondensation reaction was stopped, discharged into cold water in a strand form, and immediately cut to obtain pellets. The obtained 2,6-PEN resin pellets had an intrinsic viscosity of 0.65 and a POSS content of 4.7% by weight. The dispersibility of POSS was good, and the average dispersion diameter was 29 nm.

  Table 1 shows the results of making test pieces using the PECG-POSS-containing 2,6-PEN pellets and evaluating the bending characteristics and warpage. It had a glass transition temperature of 130 ° C. and a melting point of 272 ° C., and had excellent performance in bending elastic modulus, bending strength, and warpage characteristics.

Comparative Example 4
The same procedure as in Example 9 was carried out except that PECG-POSS was not added.

  Table 1 shows the results of preparing test pieces using the 2,6-PEN chip and evaluating the bending characteristics and warpage. Both bending elastic modulus and bending strength were inferior. It should be noted that the warpage could not be measured because the molded product was deformed.

Example 10
1 kg of dimethyl terephthalate, 0.92 kg of 1,4-butanediol, and 0.90 g of tetrabutoxytitanium were charged into the reactor and heated. The temperature inside the can was gradually raised to 135 to 235 ° C. together with the distillation of methanol, and when the distillation of methanol was almost complete, the transesterification reaction was completed, and the entire reaction product was transferred to a polycondensation tank. Subsequently, PECG-POSS (5.0% by weight with respect to the produced polymer) was added to the reaction system to which the reaction product had been transferred and stirred for 10 minutes, and then the low polymer was added at 48 rpm. While stirring, the temperature of the reaction system was gradually raised from 230 ° C. to 245 ° C., and the pressure was lowered to 35 Pa. The time to reach the final temperature and final pressure was both 60 minutes. When the predetermined stirring torque was reached, the reaction system was purged with nitrogen, returned to normal pressure, the polycondensation reaction was stopped, discharged into cold water in a strand form, and immediately cut to obtain pellets. The obtained PBT resin pellets had an intrinsic viscosity of 0.95 and a POSS content of 4.7% by weight. The dispersibility of POSS was good, and the average dispersion diameter was 76 nm.

  Table 1 shows the results of making test pieces using the PECG-POSS-containing PBT resin pellets and evaluating the bending characteristics and warpage. It had a glass transition temperature of 44 ° C. and a melting point of 237 ° C., and had excellent performance in terms of flexural modulus, flexural strength and warpage properties.

Comparative Example 5
The same procedure as in Example 10 was performed except that PECG-POSS was not added.

  Table 1 shows the results of making test pieces using this PBT chip and evaluating the bending characteristics and warpage. Both bending elastic modulus and bending strength were inferior. It should be noted that the warpage could not be measured because the molded product was deformed.

Example 11
1 kg of dimethyl terephthalate, 0.78 kg of 1,3-propanediol and 0.40 g of tetrabutoxytitanium were charged into the reactor and heated. The temperature inside the can was gradually raised to 135 to 230 ° C. together with the distillation of methanol, and the transesterification reaction was terminated when the distillation of methanol almost disappeared, and the entire reaction product was transferred to a polycondensation tank. Subsequently, PECG-POSS (5.0% by weight with respect to the produced polymer) was added to the reaction system to which the reaction product had been transferred and stirred for 10 minutes, and then 0.60 g of tetrabutoxy titanium. Was added. Thereafter, while stirring the low polymer at 48 rpm, the reaction system was gradually heated from 235 ° C. to 265 ° C., and the pressure was reduced to 40 Pa. The time to reach the final temperature and final pressure was both 60 minutes. When the predetermined stirring torque was reached, the reaction system was purged with nitrogen, returned to normal pressure, the polycondensation reaction was stopped, discharged into cold water in a strand form, and immediately cut to obtain pellets. The obtained polyester pellets had an intrinsic viscosity of 0.92 and a POSS content of 4.7% by weight. The dispersibility of POSS was good, and the average dispersion diameter was 30 nm.

  Table 1 shows the results of preparing test pieces using the PECG-POSS-containing PPT resin pellets and evaluating the bending characteristics and warpage. It had a glass transition temperature of 56 ° C. and a melting point of 231 ° C., and had excellent performance in bending elastic modulus, bending strength, and warpage characteristics.

Comparative Example 6
The same procedure as in Example 11 was performed except that PECG-POSS was not added.

  Table 1 shows the results of making test pieces using this PPT chip and evaluating the bending characteristics and warpage. Both bending elastic modulus and bending strength were inferior. It should be noted that the warpage could not be measured because the molded product was deformed.

Example 12 and Example 13
The same procedure as in Example 1 was performed except that the amount of POSS used was changed. The dispersibility of POSS was good, and the average dispersion diameter was 1 μm (1000 nm) or less.

  Table 1 shows the results of preparing test pieces and evaluating the bending characteristics and warpage. The glass transition temperature increased, and the flexural modulus, flexural strength and warpage characteristics were good.

Comparative Example 7
The same procedure as in Example 1 was performed except that silicon tetranitride particles (particle diameter 0.1 ± 0.05 μm, concentration 5.0 wt% EG slurry) were used, but the dispersibility of POSS was poor, and 5 μm or more. Coarse particles were present.

  Table 1 shows the results of evaluation of the bending properties and warpage of the test pieces, but no improvement in thermal properties was observed for both the glass transition temperature and the melting point, and the flexural modulus, bending strength and warpage properties were inferior. .

Claims (5)

A polyhedral oligometric silsesquioxy represented by the following general formula and satisfying (1) and (2) when producing a polyester comprising a difunctional acid component mainly composed of dicarboxylic acid and at least one glycol component. A method for producing a polyester composition, wherein sun (POSS) is added at any stage until the polymerization of the polyester is completed.
(RSiO _1.5 ) _n (A)
(RSiO _1.5 ) _l (RXSiO) _k (B)
[In the general formulas (A) and (B), R is selected from a hydrogen atom, a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms, or a silicon atom-containing group having 1 to 10 silicon atoms; All may be composed of the same or plural groups. In the general formula (B), X is OR ₁ (R ₁ is a hydrogen atom, an alkyl group, an aryl group, a quaternary ammonium radical), a halogen atom, or at least one functional group selected from R, and (RXSiO ) X in _k may be the same or different. Further, two X in (RXSiO) _k may be connected to each other to form a connection structure represented by the following general formula (C).

Y and Z are selected from the same group of groups as X, and Y and Z may be the same or different. n is an integer of 6 to 14, l is an integer of 2 to 12, and k is 2 or 3. ]
(1) Weight reduction rate at Tp by thermogravimetric analysis is 5% by weight or less (2) Melting point is Tp or less, provided that Tp = Tm + 30 ° C.
Tm = melting point of polyester (° C)   70% or more of R in the general formula (A) or (B) of polyhedral oligometric silsesquioxane (POSS) is pentyl group, hexyl group, octyl group, cyclohexyl group, cyclopentyl group, phenyl group, trimethylsiloxy group The method for producing a polyester composition according to claim 1, wherein one or more of norbornenylethyl groups are present.   3. The method for producing a polyester composition according to claim 1, wherein the polyhedral oligometric silsesquioxane (POSS) is a cage mixture which is a mixture of POSS molecules having different numbers of Si.   The method for producing a polyester composition according to any one of claims 1 to 3, wherein the amount of polyhedral oligometric silsesquioxane (POSS) added is 20% by weight or less.   The method for producing a polyester composition according to any one of claims 1 to 4, wherein the polyester is polyethylene terephthalate.