JP2001302896A - Polyester resin composition and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyester resin composition excellent in dispersibility of inorganic particles and having a low rate of increase in filtration pressure, and to provide a method for producing the polyester resin composition. SOLUTION: This polyester resin composition comprises a polyester resin composed of terephthalic acid as a main acid component and trimethylene glycol as a main glycol component and inorganic particles having 0.2-3 μm primary average particle diameter and has <=0.7 MPa/h rate of increase in filtration pressure when the resin composition is filtered through a wire net filter having 25 mmϕ inside diameter and 20 μm sieve opening at 250 deg.C and at 30 g/min filtration velocity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester resin composition having excellent dispersibility of inorganic particles and a low rate of increase in filtration pressure, comprising terephthalic acid as a main acid component and trimethylene glycol as a main glycol component, and a polyester resin composition thereof. It relates to a manufacturing method.

[0002]

2. Description of the Related Art Polyesters, particularly polyethylene terephthalate (PET), are widely used as fibers, films and other molded articles because of their excellent physical and chemical properties, but generally have poor flexibility. As a method for imparting flexibility to a PET film, a method of copolymerizing PET with polytetramethylene glycol, a method of copolymerizing dimer acid (JP-A-6-79776), or a method of adding an ionomer (JP-A-6-79776) JP-A-52-84244) has been proposed, but the PET produced by these methods has insufficient heat resistance and weather resistance.

On the other hand, polytrimethylene terephthalate (PTT) comprising terephthalic acid and trimethylene glycol
Is known as a material having excellent flexibility, and it has been proposed to use it as a material for carpets in the form of fibers (Japanese Patent Application Laid-Open No. 49-21256). In other words, PTT has excellent flexibility, its glass transition temperature and melting point are very close to those of nylon 6, and it has little effect on changes in physical properties due to moisture absorption. It is expected to be used for such purposes. However, PTT does not have good molding workability in the molding process, and causes undesired troubles such as deterioration of workability due to poor slipperiness of the molded product and reduction in product value.

With respect to PET, in order to solve these problems, many methods have been proposed for improving the slipperiness of the surface of a molded article by adding inorganic particles to the PET to form appropriate irregularities on the surface of the molded article. ing. For example, a method of adding inorganic particles such as silicon oxide, titanium dioxide, calcium carbonate, talc, and kaolin to polyester (for example,
No. 133431). However, in these methods, coarse particles are often mixed, and when these coarse particles are mixed, not only does the quality of the molded product deteriorate, but also the pressure rise speed of the filter during molding is increased, and the productivity is reduced. .
Also, in fiber applications, inorganic particles are included to control raster and improve concealment.If coarse particles of inorganic particles are mixed, filter clogging during spinning occurs and productivity is reduced. It is not preferable because of lowering or breakage of single yarn.

[0005]

The problem to be solved by the present invention is to improve the above-mentioned problems, to improve the dispersibility of the particles in the PTT, and to improve the processability when forming a fiber, film or resin molded product. Polyester resin composition with excellent single-fiber breakage for fibers, excellent smoothness and uniformity of film surface for films, and excellent dimensional stability and impact resistance for resin molded products. And a method for producing the same.

[0006]

The present invention solves such a problem, and the gist of the invention is as follows. (1) A terephthalic acid as a main acid component, a polyester resin containing trimethylene glycol as a main glycol component, and inorganic particles having a primary average particle size of 0.2 to 3 μm, and a wire mesh filter having an inner diameter of 25 mmφ and an opening of 20 μm. hand,
A polyester resin composition having a filtration pressure increasing rate of 0.7 MPa / h or less when filtered at a temperature of 250 ° C. and a filtration rate of 30 g / min. (2) A glycol dispersion of inorganic particles having a primary average particle size of 0.2 to 3 μm, the opening is twice or more the primary average particle size of the inorganic particles, after filtering through a filter having a size of 30 μm or less, polyester low polymer And the polycondensation reaction is carried out to produce the polyester resin composition according to the above (1).

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The polyester resin in the present invention has terephthalic acid as a main acid component and trimethylene glycol as a main glycol component, and the acid component includes isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, succinic acid, and the like. A small amount of ethylene glycol, tetramethylene glycol, cyclohexane dimethanol, or the like, or polyethylene glycol, polypropylene glycol, or a copolymer thereof may be copolymerized with the glycol component.

The polyester resin composition of the present invention contains inorganic particles having a primary average particle diameter of 0.2 to 3 μm, and is filtered at a temperature of 250 ° C. and a filtration rate of 30 g / min through a wire mesh filter having an inner diameter of 25 mmφ and an opening of 20 μm. When the filtration pressure rise rate is 0.7MPa /
must be less than or equal to h. When the primary average particle size of the inorganic particles is less than 0.2 μm, secondary aggregation is likely to occur, and it is difficult to uniformly disperse the particles in the polyester resin. On the other hand, if the primary average particle size exceeds 3μm, the filter pressure increases during molding, filter clogging occurs during spinning, and productivity may decrease, and in some cases,
It is not preferable because the quality of the molded article is impaired.

The inorganic particles having a primary average particle size of 0.2 to 3 μm include silicon oxide such as colloidal silica, wet silica, and dry silica, titanium oxide, calcium carbonate, kaolin, and the like.
Examples include particles of talc, alumina, zeolite, barium sulfate, and the like. These inorganic particles may be coated on the surface of the inorganic particles with a compound different from the composition inside the particles, or may be treated with a silane coupling agent or the like.

The content of the inorganic particles in the polyester resin composition may be appropriately selected according to the application, but is generally preferably in the range of 0.01 to 10% by mass. When the content is less than 0.01% by mass, the effect of containing the inorganic particles is reduced,
On the other hand, if it exceeds 10% by mass, it is difficult to uniformly disperse the inorganic particles in the polyester resin, which is not preferable.

If the rate of increase of the filtration pressure at the time of filtration at a temperature of 250 ° C. and a filtration rate of 30 g / min exceeds 0.7 MPa / h using a wire mesh filter having an inner diameter of 25 mmφ and an opening of 20 μm, the filter pressure increases during molding. In addition, filter clogging may occur during spinning and productivity may be reduced, and in some cases, the quality of a molded product is deteriorated, which is not preferable.

The polyester resin composition of the present invention can be produced by the following method, but is not limited to this method. For example, an esterification reaction or a transesterification reaction of terephthalic acid or an ester-forming derivative thereof with trimethylene glycol is performed to obtain a reaction product having an esterification reaction rate of 92 to 98%. 230 ℃ under reduced pressure of 5hPa or less
The polycondensation reaction is performed at a temperature of ~ 260 ° C.

As the polycondensation catalyst, metal compounds such as antimony, germanium, tin, titanium, zinc and cobalt, and organic sulfonic acid compounds such as sulfosalicylic acid are used, and tetrabutyl titanate and antimony trioxide are particularly preferable. Used. The addition amount of the catalyst is 5 × 10 ^{−5 to} 5 × 1 per 1 mol of the acid component constituting the polyester resin.
0 to ³ mol is preferable, and 1 × 10 ⁻⁴ to 2 × 10 ⁻³ mol is more preferable.

In the present invention, the inorganic particles are dispersed in a medium and added to the polyester low polymer. The medium in which the inorganic particles are dispersed is glycol, preferably trimethylene glycol. The concentration of the dispersion is not particularly limited, but is preferably 2 to 15% by mass. If the concentration of the dispersion is too high, secondary aggregation of the inorganic particles is liable to occur, and not only does the operability of filter filtration of the dispersion decrease, but also the filter pressure increases during molding and filter clogging occurs during spinning. There is not preferred. Also, if the concentration of the dispersion is too low, it is necessary to add a large amount of the dispersion, the temperature of the polyester low polymer immediately after the addition is too low, the polyester low polymer solidifies, or the reaction time It is not preferable because the production efficiency may be reduced due to the lengthening.

In the present invention, the dispersion of the inorganic particles is filtered through a filter having a mesh size of not less than twice the primary average particle diameter of the inorganic particles and not more than 30 μm, and added to the polyester low polymer. The filter opening is 2 times the primary average particle size of the inorganic particles.
If it is less than twice, the operability of the dispersion by filtration is significantly reduced. Also, if the filter opening exceeds 30 μm, coarse particles are mixed into the polyester resin, which may cause an increase in filter pressure during molding and clogging of the filter during spinning, and in some cases, impair the quality of molded products. Is not preferred.

A dispersion of the inorganic particles prepared and filtered as described above is added to a polyester low polymer, and the mixture is stirred and mixed to carry out a polycondensation reaction. As a specific mixing method,
A method of adding and mixing using a propeller-type, paddle-type, or turbine-type stirring blade in an esterification reaction tank or a polycondensation reaction tank, or feeding between an esterification reaction tank and a polycondensation reaction tank using a line mixer. A method of mixing in a liquid with a liquid pipe is exemplified.

The polyester resin composition of the present invention may contain additives such as a pigment, a color improving agent such as a metal compound, a flame retardant, an antioxidant, etc., as required, in addition to the inorganic particles. it can.

[0018]

According to the production method of the present invention, since the glycol dispersion of inorganic particles is filtered through a filter having a specific opening, the amount of coarse particles in the resin is small, the dispersibility of the inorganic particles is excellent, and the filtration is excellent. A polyester resin composition having a low pressure rise rate can be obtained. By using this composition, in the case of a fiber, there are few single yarn breaks, in the case of a film, excellent in smoothness and uniformity of the film surface, and in the case of a resin molded product, the dimensional stability and impact resistance are excellent. A molded article can be obtained.

[0019]

The present invention will be described more specifically with reference to the following examples. In the examples, the characteristic values were measured as follows. (1) Primary average particle diameter of inorganic particles Measured by an electric detection band method using Coulter's MultiSizer II. (2) Content of Inorganic Particles Elemental analysis was performed using a fluorescent X-ray analyzer 3270 manufactured by Rigaku Corporation to determine the content of inorganic particles. (3) Intrinsic viscosity [η] Measured at a temperature of 20 ° C. using an equal mass mixture of phenol and ethane tetrachloride as a solvent. (4) Filtration pressure rise rate The pellet-shaped resin was dried at 110 ° C under reduced pressure for 7 hours, melt-extruded with an extruder, and had an aperture of 25 μm in inner diameter of 25 μm.
The filter pressure at the time of filtration at a temperature of 250 ° C. and a filtration rate of 30 g / min was measured with a wire mesh filter of No. 3, and the rate of increase of the filtration pressure was determined. (5) Number of Coarse Particles in Film The film is cut into 5 cm × 5 cm, and 20 samples are produced. Polarizing plates were placed above and below one sample, and the sample was irradiated with transmitted light using a stereoscopic microscope. The sample was rotated, and it was checked that interference light leaked due to the presence of foreign matter. Next, under an optical microscope, the size of the foreign material checked previously was measured with a micrometer, and the number of foreign materials having a size of 80 μm or more was counted. The total number of counts for 20 samples (corresponding to 500 cm ² ) was defined as the number of coarse particles, and those having a count of 100 particles / 500 cm ² or less were regarded as acceptable.

Example 1 <Production of PTT> 33.2 kg of terephthalic acid and 24.35 kg of trimethylene glycol (the molar ratio of terephthalic acid to trimethylene glycol 1 / 1.6) were charged into an esterification reactor, and the temperature was adjusted to 2%.
The reaction was carried out at 50 ° C. under a pressure of 50 hPaG to obtain a PTT oligomer having an esterification reaction rate of 95%. The obtained esterification reaction product was charged into a polycondensation reaction vessel, and was previously filtered through a filter having a mesh size of 5 μm, and a dispersion of silica in trimethylene glycol having a primary average particle diameter of 1.3 μm (silica concentration: 5% by mass)
Was added so that the content became 1.0% by mass, and the mixture was stirred and mixed with a stirring blade for 10 minutes. Then, 4 × 10 ⁻⁴ mol of tetrabutyl titanate was added to 1 mol of the acid component, and the pressure was gradually reduced to 70%.
Then, the polycondensation reaction was performed at a temperature of 250 ° C. for 3 hours. Pelletization was performed by a conventional method to obtain PTT pellet A having an intrinsic viscosity of 0.76.

<Production of film>
After drying at 10 ° C. for 7 hours and blending 10% by mass with PTT pellets having an intrinsic viscosity of 0.76 and containing no inorganic particles, the mixture was melt-extruded at 260 ° C. to obtain an unstretched film.
It is stretched three times in each of the vertical and horizontal directions and 90 ° C
To obtain a film having a thickness of 50 μm.

Examples 2 to 5, Comparative Examples 1 to 4 The type of inorganic particles, the primary average particle size, the content in PTT, and the opening of the filter when filtering the inorganic particle dispersion are shown in Table 1. The procedure was performed in the same manner as in Example 1, except that
Table 1 shows the results of Examples 1 to 5 and Comparative Examples 1 to 4.

[0023]

[Table 1]

Examples 1 to 5 showed good characteristics, but the comparative example had the following problems. In Comparative Example 1, the aperture of the filter for filtering the dispersion liquid was large, so that the pressure of the filter during resin filtration was high. Also, the number of coarse particles in the film was large. In Comparative Example 2, since the primary average particle size of the inorganic particles was small, silica re-agglomerated during polymerization, and the pressure rise rate of the filter during resin filtration was high. Also, the number of coarse particles in the film was large. In Comparative Example 3, the aperture of the filter for the dispersion liquid was large, so that the pressure rise rate of the filter during resin filtration was high. Also, the number of coarse particles in the film was large. In Comparative Example 4, since the primary average particle size of the inorganic particles was large, the filter pressurizing speed during resin filtration was high. Also, the number of coarse particles in the film was large.

[0025]

EFFECT OF THE INVENTION By using the polyester resin composition of the present invention which is excellent in dispersibility of inorganic particles and has a low rate of increase in filtration pressure, productivity of films and fibers is improved. A product having excellent surface uniformity and having few defects such as fluff due to yarn breakage can be obtained in the case of fiber.

Continued on the front page F-term (reference) 4J002 CF051 DE136 DE146 DE236 DG046 DJ006 DJ016 DJ036 DJ046 FD176 GK01 4J029 AA03 AB05 AE02 AE03 BA04 CB06A HA01 HB01 JA093 JA123 JA203 JA293 JB131 JC361 JF143 JF163 JF181 JF223 J321 J321 KE08 KE15

Claims (2)

[Claims] Claims: 1. A wire mesh containing a polyester resin containing terephthalic acid as a main acid component and trimethylene glycol as a main glycol component, and inorganic particles having a primary average particle size of 0.2 to 3 μm, and having an inner diameter of 25 mmφ and an opening of 20 μm. A polyester resin composition characterized in that the filtration pressure rise rate when filtering at a temperature of 250 ° C. and a filtration rate of 30 g / min with a filter is 0.7 MPa / h or less. 2. A glycol dispersion of inorganic particles having a primary average particle size of 0.2 to 3 μm is filtered through a filter having a mesh size of at least twice the primary average particle size of the inorganic particles and 30 μm or less. The method for producing a polyester resin composition according to claim 1, wherein the polycondensation reaction is performed by adding to the polymer.