JP2842078B2 - Method for producing polyester composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyester composition by adding and mixing a liquid slurry obtained by dissolving or dispersing inorganic particles and / or organic particles into polyester using a vent-type molding machine. About.

[0002]

2. Description of the Related Art Polyesters, particularly polyethylene terephthalate and polyethylene naphthalate, are widely used as raw materials for fibers, films and various other molded products due to their excellent physical and chemical properties. However, polyester molded products are generally inferior in slipperiness, so that there is a problem that workability such as processability in the molding process is deteriorated, and that the handleability and value of the product are reduced.

[0003] As measures to solve such problems, many proposals have been made to improve the slipperiness by adding inorganic particles and organic particles to polyester and mixing them to give appropriate irregularities to the surface of a molded product. Some have been converted.
For example, in the polyester polymerization step, inert inorganic particles (silicon oxide, titanium dioxide, calcium carbonate, talc, kaolinite, etc.) or organic polymers (divinylbenzene polymer, styrene / divinylbenzene copolymer, benzoguanamine / formaldehyde resin) , A polytetrafluoroethylene-hexafluoropropylene copolymer, a polyphenylester resin, etc.).
No. 1, JP-A-55-125247).

[0004] In these methods, however, coarse particles are often mixed in the case of inert inorganic particles. The incorporation of the coarse particles causes, for example, a decrease in the electromagnetic conversion characteristics of the film for a magnetic tape and a cause of dropout. In addition, there is a disadvantage that the quality and performance are impaired. As a method for removing the coarse particles described above,
A method of pulverizing inert inorganic particles and performing a classification operation and the like, and adding this during a polyester synthesis reaction in a slurry state or a solution state, etc., using a single-screw or twin-screw extruder to form polyester and powdery inert particles. A method of kneading and compounding while applying a strong shearing force for a long time is known. However, the former has a disadvantage that the operation time and cost required for the pulverization and classification operations of the inert inorganic particles are too large, and it is difficult to completely avoid the incorporation of coarse particles. Further, in order to switch brands in recent years, a polyester composition of another type having added value is produced from one kind of base polymer, but there is a disadvantage that a large amount of loss occurs when added during the synthesis reaction. On the other hand, the latter has a drawback that a strong shearing force is applied for a long period of time, so that the intrinsic viscosity of the polyester is remarkably reduced, and the moldability of the polyester composition and the quality and performance of the product are deteriorated.

As a countermeasure for solving such a drawback, a vent-type molding machine is used to form at least two kinds of crosslinked polymer particles having different particle diameters using water and / or a liquid such as an organic compound having a boiling point of 200 ° C. or less as a medium. Slurry of molecular particles and boiling point 200
There has been proposed a method of adding and mixing a slurry of spherical inorganic particles using a liquid at a temperature of not more than ℃ to polyester (see JP-A-3-221556 and JP-A-3-250043). However, any of the methods of adding and mixing the slurry using these vent-type molding machines greatly reduces the intrinsic viscosity of the polyester. In particular, when using a slurry containing water as a medium or when adding and mixing a large amount of slurry to produce a polyester composition having a high particle concentration, the intrinsic viscosity of the polyester is remarkably reduced, and the film formation, the yarn forming step, etc. The occurrence of troubles in the post-process is inevitable. Further, the addition of a large amount of the dispersion medium causes a problem that the medium such as water accumulates in the molding machine, thereby lowering the operation stability.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the intrinsic viscosity of polyester when adding inorganic particles and organic particles to a polyester by using a vent-type molding machine, thereby deteriorating the operation stability. It is an object of the present invention to provide a method for producing a polyester composition which is excellent in moldability, product quality and performance without causing the polyester composition.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a polyester composition in which inorganic particles and / or organic particles are added and mixed by using a vent-type molding machine. A liquid slurry in which the inorganic particles and / or organic particles are dispersed in a medium is added to the polyester flowing therein. Immediately after the addition, the polyester is retained and substantially melted. It can be achieved by vaporizing and removing the slurry through a vent hole provided upstream of the addition position of the slurry.

Thus, the slurry is added immediately before the polyester flowing in the vent-type molding machine is retained and substantially completely melted, that is, the polyester is substantially completely melted immediately after the slurry is added. In addition, the kneading time between the polyester and the inorganic or organic particles can be shortened, and the decrease in the viscosity of the polyester can be minimized. In addition, since the slurry medium vaporized simultaneously with the melting of the polyester can be quickly removed from the vent hole provided upstream of the slurry addition position, the accumulation of the medium in the vent-type molding machine can be prevented, and the operation can be prevented. The deterioration of stability can be prevented. In addition, a large amount of slurry can be added and mixed in order to quickly remove the medium of the slurry during the stay. Therefore, a high-concentration master (base polymer) can be manufactured, and another type of polyester having added value can be manufactured from the base polymer without causing loss.

In the present invention, "substantially melting" means that the polymer becomes liquid and can pass through a retaining portion such as a reverse screw or a dam. Hereinafter, the present invention will be specifically described with reference to the drawings. The vent-type molding machine used in the present invention may be any of an extrusion molding machine and an injection molding machine, and is not particularly limited as long as it has a slurry addition port, at least one vent hole, and a polymer retention means. It is not something to be done.

FIG. 1 shows an example of a vent type twin screw extruder used in the present invention, wherein 1 is a molding machine, 2 is a heating cylinder, 3 is a screw, 4 is an extrusion port, and M is a drive of a screw 3. Device. The molding machine 1 is provided with a polymer inlet 5, a vent hole 6, a slurry addition port 7, and a vent hole 6 'in order from the drive unit M toward the extrusion port 4. As means for retaining the polymer, a reverse screw 8 is provided on the screw 3 near the slurry addition port 7, and a reverse screw 8 ′ is also provided on the screw 3 near the extrusion port 4.

In such a vent-type twin-screw extruder 1, a chip-like or powdery polyester is charged into a cylinder 2 from a polymer charging port 5, and is fed to an extrusion port 4 by a screw 3 rotated by a driving device M. Transported from right to left. This polyester can be heated and softened by controlling the temperature of the cylinder 2 in order to improve the fluidity in the cylinder 2, but is not completely melted in order to prevent a decrease in viscosity. Next, the polyester flows in the cylinder 2 to reach the slurry addition port 7, where the slurry prepared beforehand is added. It is preferable to add pressure to the slurry to overcome the vapor pressure in the heating cylinder 2 and to add and mix the slurry.

As soon as the slurry is added,
The polyester reaches the part of the reverse screw 8 and its flow is stopped and retained. Preferably, the positional relationship between the slurry addition port 7 and the reverse screw 8 is adjusted so that the polyester stays about 0 to 10 seconds after the addition of the slurry. During the dwell, the polyester substantially completely melts, in part due to the shear forces of the counter-thread 8 and in part due to the heat supplied from the heater of the cylinder 2.
The slurry medium evaporates. The reverse screw 8 is provided not only with the screw 3 but also with special means, preferably a disk or a rotor, to increase the shearing force acting on the polyester to promote melting and vaporization, and to improve the polyester and inorganic particles and the like. It is preferable to promote mixing with the organic particles.

The vaporized medium is removed outside through a vent hole 6 provided upstream of the slurry addition port 7.
The point in removing the vaporized medium is to minimize the amount of the medium contained in the polyester substantially completely melted by the stagnation. Preferably, the amount of the medium removed from the vent hole 6 is 90% or more, more preferably 95% or more. For this purpose, it is preferable to immediately remove the vaporized medium from the vent hole 6. For this reason, the vent hole 6 is desirably provided as close to the reverse screw 8 as possible within a range in which the polyester does not vent up (a phenomenon in which the polyester comes out of the vent hole). Further, at least one of the vent holes is 100
The pressure should be reduced to not more than torr, preferably not more than 50 Torr, more preferably not more than 30 Torr. Especially,
The polyester which has been substantially completely melted by the residence may be exposed under reduced pressure to remove residual media.

Thus, the polyester is substantially completely melted, and is mostly kneaded with a slurry of inorganic or organic particles by a screw 3 by removing a large amount of medium.
It flows through the cylinder 2 toward the extrusion port 4,
The remaining medium is vaporized again by the reverse screw 8 ′ to vaporize the remaining medium, removed from the vent hole 6 ′, and extruded from the extrusion port 4 after adjusting the melting temperature.

In the present invention, the retention means of the vent-type molding machine is not limited to the above-mentioned reverse screw. When the polyester is not melted, the flow is stopped by retaining the polyester. In some cases, a damper or the like that smoothly passes without stagnation may be used. When the polymer is in a non-melted state, the dam suppresses the flow and retains the polymer. However, when the polymer is melted, the polymer flows through the gap between the outer periphery of the ring attached to the screw and the cylinder of the molding machine.

The polyester used in the present invention includes:
There are polymers made from a difunctional acid component and a glycol component. Examples of the difunctional acid component include an aromatic or aliphatic dicarboxylic acid or an ester-forming derivative thereof, and specific examples of the aromatic or aliphatic dicarboxylic acid include:
There are terephthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, sebacic acid, dimer acid and the like. Examples of the ester-forming derivative include dimethyl terephthalate, dimethyl isophthalate, dimethyl 2,6-naphthalenedicarboxylate, dimethyl sebacate, and dimethyl dimer.

Examples of the glycol component include ethylene glycol, propylene glycol, diethylene glycol, propylene glycol, polyethylene glycol 1,4-cyclohexanedimethanol and the like.
A third component other than the difunctional acid component and the glycol component may be copolymerized. Examples of such a third component include diol components such as diethylene glycol, propylene glycol, neopentyl glycol, polyalkylene glycol, and 1,4-cyclohexanedimethanol, adipic acid, sebacic phthalic acid, and 5-sodium sulfoisophthalic acid. Polyfunctional dicarboxylic acid components such as dicarboxylic acid, trimetic acid, and pyrometic acid;
And oxycarboxylic acid components such as oxyethoxybenzoic acid.

In the present invention, as the inorganic particles and / or organic particles to be mixed with the polyester, almost all of those which can be added to and mixed with known polyesters can be used. Examples of the inorganic particles include titanium oxide, silica oxide, aluminum oxide, calcium carbonate, zirconium oxide, and the like. Examples of the organic particles include styrene polymer, divinylbenzene polymer, styrene / divinylbenzene copolymer, ethylene glycol dimethacrylate polymer, trimethylolpropane trimethacrylate polymer, benzoguanamine / formaldehyde resin, and polytetrafluoroethylene. -Hexafluoropropylene copolymer, polyphenylester resin and the like.

The medium of the slurry used in the present invention is not particularly limited as long as it can disperse the above-mentioned inorganic particles and / or organic particles to form a slurry. For example, almost all known media such as water and liquid having a boiling point of 200 ° C. or less can be used. Among them,
Water, methanol, ethanol, ethylene glycol and the like are preferable from the viewpoint of economy and handleability. In particular, water is the most preferred medium in terms of safety.

[0020]

【Example】

Example 1 Using a vent-type twin-screw extruder shown in FIG. 1, undried polyethylene terephthalate having an intrinsic viscosity of 0.650 containing 0.4% by weight of water was poured into a polymer injection port at a rate of 29.degree.
The mixture was charged into a cylinder at 0 ° C., the screw was rotated to flow at a flow rate of 200 kg / hr, and a water slurry of spherical titanium oxide particles having an average particle diameter of 0.3 μm (moisture content of polyester) was added through a slurry addition port. 10.0% by weight)
Was added and mixed so that the titanium oxide content in the polyester finally became 7% by weight. Immediately after the addition of the water slurry (after the lapse of 5 seconds), the mixture of the polyester and the slurry reached the reverse thread portion, where it was retained and completely melted. The vent hole 6 provided in the vicinity of the slurry addition port was evacuated to 10 torr (torr), and about 9
8% of the water was removed as steam.

The polyester thus melted and the spherical titanium oxide particles (slurry) from which the medium has been removed are transported while kneading with a screw, and are again retained with a reverse screw near the extrusion port 4 to vaporize the residual solvent. After removal from the pressure vent hole 6 ′, the polyester composition at a temperature of 280 ° C. was extruded from the extrusion port 4. The operation stability during the production of this polyester composition was good, and the intrinsic viscosity of the obtained polyester composition was measured by the following method. Was. Measurement method of intrinsic viscosity of polyester : o-chlorophenol was dissolved in a solvent, particles were removed by centrifugal sedimentation, and measured at 25 ° C. There is no practical problem as long as the intrinsic viscosity of the polyester after the addition and mixing of the particles is reduced to 0.030 or less.

Next, using a polyester containing no titanium oxide particles, the above-mentioned polyester composition was adjusted so that the content of spherical titanium oxide particles was 0.5% by weight, and then melt-extruded at 290 ° C. The film was wound around a casting drum having a surface temperature of 30 ° C. using an electrostatic application casting method, and cooled and solidified to obtain an unstretched film having a thickness of 150 μm. This unstretched film is stretched 3.4 times in the machine direction at 100 ° C.
The film was stretched 3.6 times in the horizontal direction at 90 ° C., and then heat-set at 210 ° C. to obtain a biaxially stretched film having a thickness of 15 μm. As a result of evaluating the characteristics of this film, it had good physical properties. Examples 2 to 8, Comparative Examples 1 to 6 Under the same conditions as in Example 1 except that the structure of the vented twin-screw extruder, the type of the added particles, and the composition of the slurry were changed as shown in Table 1, The polyester compositions of Examples 2 to 8 and Comparative Examples 1 to 6 were produced by adding and mixing the slurry to polyethylene terephthalate. When these 13 types of polyester compositions were evaluated in the same manner as in Example 1, the results shown in Table 1 were obtained.

[0023] From Table 1, it was found that all of the polyester compositions of Examples 2 to 8 had good operation stability during the production, and the decrease in the intrinsic viscosity was 0.030 or less. Further, a biaxially oriented film was prepared from these polyester compositions in the same manner as in Example 1, and the physical properties of the film were evaluated.

On the other hand, the polyester compositions of Comparative Examples 1 to 6 have poor operation stability and a decrease in intrinsic viscosity of 0.1%.
030. Further, a biaxially oriented film was prepared from these polyester compositions in the same manner as in Example 1,
When the physical properties of the film were evaluated, all were poor. Example 9 and Comparative Example 7 A polyester composition was produced in the same manner as in Example 1 and Comparative Example 1, except that polyethylene terephthalate was changed to polyethylene naphthalate. These two
The operation stability and intrinsic viscosity during the production of the various polyester compositions were evaluated in the same manner as in Example 1, and the results shown in Table 1 were obtained.

[0025]

According to the present invention, the following excellent effects can be obtained. (1) When the slurry of the inorganic particles and / or the organic particles is added to and mixed with the polyester, a decrease in the intrinsic viscosity of the polyester can be minimized. (2) It becomes possible to add and mix a slurry of inorganic particles and / or organic particles to polyester with good operation stability. (3) Since it is possible to add and mix a large amount of slurry of inorganic particles and / or organic particles to polyester,
A polyester composition containing a high concentration of particles is obtained.

[Brief description of the drawings]

FIG. 1 is a side view showing an example of a vent type molding machine used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Molding machine 2 Cylinder 5 Polymer inlet 6,6 'Vent hole 7 Slurry addition port 8,8' Reverse screw

Claims (1)

(57) [Claims] Claims: 1. Use of a vent-type molding machine to form inorganic particles and / or
Or when producing a polyester composition to which organic particles are added and mixed, a liquid slurry in which the inorganic particles and / or organic particles are dispersed in a medium is added to the polyester flowing in the vent-type molding machine, and the slurry Immediately after the addition, the polyester is retained and substantially melted, the medium of the slurry is vaporized, and the polyester is removed through a vent hole provided on the upstream side of the addition position of the slurry. Manufacturing method.