JPH0717819B2 - Polyester composition and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a polyester composition and a production method. More specifically, the present invention relates to a polyester composition containing a specific silicon dioxide and a specific amount of a sulfur atom-containing compound and a method for producing the same, and more specifically to the presence of fine particles of silicon dioxide in a water or glycol-based dispersion medium. The present invention also relates to a method for producing a polyester by adding an organosol and a specific amount of a sulfur atom-containing compound.

[Prior Art] Polyester typified by polyethylene terephthalate has excellent physical and chemical properties and is widely used as fibers, films, and other molded articles. However, in terms of process passability in the molding process for obtaining the above-mentioned molded product, post-processing process such as surface treatment or handleability in the product itself, unsatisfactory properties such as poor workability and reduced commercial value due to poor slipperiness. There is. For this reason, it is usually practiced that fine particles are contained in polyester so that the surface of the molded product is provided with appropriate irregularities to improve the surface smoothness of the molded product. As such fine particles, it is known that inorganic compound particles insoluble in polyester such as talc, silica, kaolin, aluminum oxide, titanium dioxide, and carbon are added to the polyester. Among these inorganic particles, as silica particles, various products having different average particle diameters are commercially available and are used for the above purpose. As a method of adding silica particles to polyester, powdery silica is physically mixed in a dispersion medium such as water, methanol or glycol, or is further dispersed by using a surfactant and a dispersant in combination to produce polyester in a slurry form. A method of adding to the step, or as disclosed in JP-A-59-108028, JP-A-56-47429, etc., water-based colloidal silica heglycol is added little by little to remove water by distillation, and water is added. Is known to be added to the polyester reaction etc. With the above method,
Compared with the method of adding powdery silica to the polyester reaction system in the form of slurry, the method of adding most of the aqueous colloidal silica by replacing it with ethylene glycol (hereinafter abbreviated as EG) is the method of adding silica particles in the dispersion medium before addition. The dispersed state is rather good.

[Problems to be Solved by the Invention] However, in any of the above methods, in the case of particles having relatively high particle surface activity such as silica particles and easily forming agglomerated secondary particles, a polyester reaction system is used. It is difficult to completely disperse it in the dispersion medium before adding it to, and after addition to the reaction, etc., it is observed that the aggregation of particles tends to proceed during the polyester production, and the obtained polyester has coarse particles. There are various agglomerated particles. The presence of coarse secondary agglomerated particles in the polyester causes yarn breakage during high-speed spinning in the fiber molding process, and when film-forming, the surface irregularities become uneven, which makes the film product valuable. When applied to a magnetic tape support such as a vapor deposition tape or a metal tape, it is not preferable because it causes a decrease in output and dropout.

The present invention is a silica particle-containing polyester obtained by a conventional method by adding a specific amount of a sulfur atom-containing compound to silicon dioxide to prevent secondary aggregation of fine particles of silicon dioxide having high surface activity. When the above is used, the above-mentioned drawbacks found in the molding process of fibers, films and the like or molded products are improved.

[Means for Solving the Problem] The present invention provides (1) a polyester composition containing silicon dioxide having an average particle diameter of 0.01 to 2.0 μ, which is obtained by the reaction of dicarboxylic acid or its ester-forming derivative with ethylene glycol. A polyester composition containing a sulfur atom-containing compound in an amount of 10 to 2000 ppm based on silicon dioxide in terms of sulfur atoms.

(2) When a polyester is produced by reacting a dicarboxylic acid or its ester-forming derivative with ethylene glycol, water of silicon dioxide having an average particle diameter of 0.01 to 2.0 μm or ethylene glycol sol and a sulfur atom-containing compound are used as sulfur atoms. A method for producing a polyester composition, characterized in that 10 to 2000 ppm of silicon dioxide is added to the reaction system at any stage of the polyester production process.

The polyester of the present invention is produced by transesterification or esterification reaction of dicarboxylic acid or its ester derivative with EG and polycondensation reaction.

The type of polyester is not particularly limited as long as it can be molded into a fiber, a film, or other molded products.
Suitable polyesters that can be molded into fibers, films and other molded articles are those in which the dicarboxylic acid component is an aromatic dicarboxylic acid, such as polyethylene terephthalate, polyethylene-p-oxybenzoate,
Polyethylene-1,2-bis (2-chlorophenoxy) ethane-4,4'-dicarboxylate, polyethylene-1,2
-Bis (phenoxy) ethane-4,4'-dicarboxylate, polyethylene-2,6-naphthalenedicarboxylate and the like can be mentioned, with polyethylene terephthalate being preferred. Of course, these polyesters may be homopolyesters or may be copolyesters, and as the components to be copolymerized, for example, diethylene glycol, neopentyl glycol, average molecular weight 150 to 20000
Polyalkylene glycol, p-xylylene glycol, 1,4-cyclohexanedimethanol, diol component such as 5-sodium sulforenzolcin, adipic acid,
Dicarboxylic acid components such as sebacic acid, phthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid, polyfunctional carboxylic acid components such as trimellitic acid and pyromellitic acid, p-oxyethoxybenzoic acid And other oxycarboxylic acid components.

The water or EG sol of silicon dioxide referred to in the present invention means silicon dioxide having an average particle diameter of 0.01 to 2.0 μ.
Physically mixed with, or further added in combination with a surfactant and a dispersant, and made into a sol, or a chemical method such as water glass, an aqueous dispersion sol of silicon dioxide produced from an alkyl silicate, Further, those obtained by substituting EG for water in the water-dispersed sol of silicon dioxide are also included.

The average particle size of silicon dioxide used in the present invention is 0.01
˜2.0 μ, and preferably 0.02 to 1.5 μ. Average particle size is
If it exceeds 2.0 μ, defects such as drop in output and dropout due to coarsening of surface protrusions of the film tend to occur in magnetic tape applications. On the other hand, particles smaller than 0.01 μm have a large increase in the viscosity of the molten polymer, which lowers the operability during the polymerization reaction and molding, and in terms of film properties, surface protrusions are insufficient and effective lubricity cannot be obtained. The content of silicon dioxide in water or EG sol of silicon dioxide is 50% by weight or less,
More preferably, at 10% by weight or less, a polyester composition having particularly excellent particle dispersibility can be obtained.

The method of adding water or EG sol of silicon dioxide of the present invention is not particularly limited and may be added as water or EG sol as it is, and further added after being appropriately diluted with an organic solvent such as EG. You may. The method of adding as EG sol is preferable.

The timing of adding silicon dioxide to water or the EG sol to the polyester reaction system is not particularly limited, but is preferably from before the transesterification or esterification reaction during the production of the polyester to the early stage of the polycondensation reaction.

The sulfur atom-containing compound of the present invention is used for the purpose of preventing aggregation of silicon dioxide in the polyester composition, and the addition method thereof is to add water to the silicon dioxide or EG sol and then add to the polyester reaction system. Method, or a method of adding to the polyester reaction system separately from water or EG sol of silicon dioxide, and is not particularly limited, but preferably after adding to water or EG sol of silicon dioxide, the polyester The method of adding to the reaction system is preferable.

The timing of addition to the polyester reaction system is not particularly limited, but is preferably from before the transesterification or esterification reaction during the production of the polyester to the early stage of the polycondensation reaction.

The sulfur atom-containing compound in the present invention is a compound having a sulfur atom in the compound such as a sulfuric acid compound, a sulfide and other sulfur compounds, preferably a sulfur atom-containing compound is a sulfate ion in the sol of the present invention, It is a compound that dissociates as sulfite ion and the like. Specific examples thereof include potassium sulfate, sodium sulfate, lithium sulfate and magnesium sulfate, but the compounds are not particularly limited to these compounds. The addition amount of the sulfur atom-containing compound is 10 to 2000 ppm, preferably 15 to 1500 ppm, and more preferably 20 to 1000 ppm in terms of S atom in the sulfur atom containing compound with respect to silicon dioxide.
If the added amount of the sulfur atom-containing compound exceeds 2000 ppm in terms of S atom with respect to silicon dioxide, secondary agglomerated particles of silicon dioxide will be generated in the polyester, and foreign substances due to the sulfur atom-containing compound will be generated. . Moreover, the addition amount
Even below 10 ppm, secondary agglomerated particles of silicon dioxide still occur in the polyester. As described above, only when the amount of the sulfur atom-containing compound of the present invention added to the polyester is 10 to 2000 ppm based on silicon dioxide in terms of S atoms, no foreign matter is contained and the particles of silicon dioxide are primary particles. It is possible to obtain a polyester composition which is present as described above, and when the polyester composition is formed into a film, a very uniform and finely rugged film surface is obtained.

Further, a chlorine compound, an aluminum compound, a zirconium compound or chlorine ions, aluminum ions, zirconium ions, etc. may be added and contained in the silicon dioxide sol of the present invention.

Further, the content of silicon dioxide in the polyester composition is preferably 5% by weight or less, and particularly preferably 2% by weight or less from the viewpoint of increasing the viscosity of the molten polymer and dispersibility of the added particles. Furthermore, metal compound catalysts such as lithium, sodium, calcium, magnesium, manganese, zinc, antimony, germanium, and titanium that are usually used in the production of polyesters, phosphorus compounds as coloring inhibitors, pigments, surfactants, inorganics other than silicon dioxide. Particles can also be added as needed.

When a film is produced from the silicon dioxide-containing polyester composition of the present invention, the polyester composition is molded into a sheet by a usual method, stretched in at least one direction, and then heat-set at a temperature of 150 ° C or higher. It is preferable to manufacture it.

The polyester film obtained by the above method has a particle concentration of 0.005 to 2.0% by weight, preferably 0.01 if the average particle diameter of the silicon dioxide of the present invention is around 0.1 μm.
~ 1.0 wt%, further if the average particle size is around 1.0μ, the particle concentration in the film is 0.001 to 1.0 wt%, preferably 0.
It has an excellent processability at the time of high-order processing for various applications in the range of 05 to 0.5% by weight, and the surface irregularities of the film are extremely uniform and fine. It can be used for various film applications, especially for magnetic recording media, and high density magnetic recording. It is preferably used as a base film for a medium.

[Examples] The present invention will be described in more detail with reference to Examples.

The characteristics in the examples were measured as follows.

A. Intrinsic viscosity of polymer Measured at 25 ° C. using O-chlorophenol as a solvent.

B. Polymer Softening Point Polymer chips were placed in a heating bath and heated at a temperature rising rate of 6 ° C./5 minutes, and the temperature at which the tip of the load penetrated into the chips by 5 mm or more was measured.

C. Particle Dispersion State in Polymer After the polymer was cut into ultrathin sections of around 800 Å using an ultrathin film preparation system, the particle dispersion state in the polymer was observed with a transmission electron microscope.

The dispersed state was determined as follows.

◯: No secondary aggregated particles are observed.

Δ: Secondary aggregation particles are slightly present and the purpose is not achieved.

X: Most of the particles are secondary agglomerated particles.

Example 1 EG was added to an aqueous sol containing Glauber's salt (Na ₂ SO ₄ · 10H ₂ O) in an amount of 700 ppm based on silicon dioxide in terms of S atoms and containing 40% by weight of silicon dioxide having an average particle diameter of 0.1μ. The replacement was completed while removing water under reduced pressure at 100 ° C.
A wt% EG sol was obtained.

Next, 100 parts by weight of dimethyl terephthalate and 70 parts by weight of EG were used as a catalyst in 0.002 parts by weight of lithium acetate and 0.04 parts by weight of magnesium acetate, and after an ester exchange reaction according to a conventional method, trimethyl phosphate was added as a coloring inhibitor in an amount of 0.01 parts by weight.
5 parts by weight, 20 parts by weight of the above-mentioned silicon dioxide EG sol were added, and then 0.02 parts by weight of antimony trioxide was added as a polymerization catalyst.

Then, polycondensation reaction was performed according to a conventional method under reduced pressure at high temperature to obtain polyethylene terephthalate having an intrinsic viscosity of 0.615 and a softening point of 260.5 ° C. As a result of observing the particle dispersion state of silicon dioxide in the polymer with a transmission electron microscope, secondary agglomerated particles were not observed and they existed almost as primary particles.
The obtained polyester and polyethylene terephthalate substantially free of particles are blended, and the thickness is 12 according to a conventional method.
A biaxially stretched film having μ and a particle content of 0.05% by weight was obtained.
When the surface of the film was observed, no coarse protrusion due to agglomeration of particles was observed.

Example 2 EG was added to an aqueous sol containing Glauber's salt (Na ₂ SO ₄ · 10H ₂ O) in an amount of 700 ppm based on silicon dioxide in terms of S atoms, and containing 30% by weight of silicon dioxide having an average particle diameter of 0.5μ. A water / EG sol containing 5% by weight of silicon dioxide was obtained.

Next, 100 parts by weight of dimethyl terephthalate, 70 parts by weight of EG and 0.002 parts by weight of lithium acetate, 0.04 parts by weight of magnesium acetate as a catalyst, after transesterification in accordance with a conventional method, 0.015 parts by weight of trimethyl phosphate as an inhibitor, the above 20 parts by weight of silicon dioxide water / EG sol was added, and then 0.02 parts by weight of antimony trioxide was added as a polymerization catalyst. Then, polycondensation reaction was carried out under a high temperature and reduced pressure according to a conventional method to obtain polyethylene terephthalate having an intrinsic viscosity of 0.613 and a softening point of 260.9 ° C.

As a result of observing the particle dispersion state of silicon dioxide with a transmission electron microscope, there was no generation of foreign matter in the polymer,
No secondary agglomerated particles were observed, and they were present as almost primary particles.

Comparative Example 1 Example 1 was used except that an aqueous sol of silicon dioxide containing 5 ppm of Glauber's salt converted to S atoms and containing 5 ppm with respect to silicon dioxide was used.
A silicon dioxide-containing polyethylene terephthalate was obtained by the same method as described above. As a result of observing the particle dispersion state of silicon dioxide in the polymer with a transmission electron microscope, many particles of silicon dioxide were secondary aggregated.

Further, a biaxially stretched film was produced from the polymer in the same manner as in Example 1. When the surface of the film was observed, coarse protrusions appeared due to the aggregation of particles.

Examples 3 to 9 and Comparative Examples 2 to 3 Silicon dioxide-containing polyethylene terephthalate was obtained in the same manner as in Example 1 except that the silicon dioxide sol shown in Table 1 was used. Examples 3-9 are within the scope of the invention and showed good particle dispersibility.

On the other hand, in Comparative Example 2, the amount of the sulfur atom-containing compound in silicon dioxide was outside the range of the present invention, and many secondary agglomerated particles of silicon dioxide were observed in the obtained polymer, and the film obtained from the polymer was found. Coarse surface protrusions appeared in the.

In Comparative Example 3, the average particle size of silicon dioxide was out of the range of the present invention, and the particle dispersibility in the obtained polymer was good, but the surface protrusions of the film obtained from the polymer became coarse. , Was unbearable for magnetic tape.

[Effect of the Invention] The present invention is a polyester composition containing a specific silicon dioxide and a specific amount of a sulfur atom-containing compound as described above, and a method for producing the same.
By adding water or EG sol of 0.01 to 2.0 μm of silicon dioxide and a specific amount of a sulfur atom-containing compound into the polyester reaction system, it is possible to obtain a uniform fine particle without containing coarse agglomerated particles which have hitherto been obtained. A polyester composition containing a large number of particles in a substantially single particle state can be obtained.

The polyester composition of the present invention can reduce clogging, yarn breakage, and film breakage in the manufacturing process of a molded article, and can obtain a molded article having a very uniform and fine surface roughness, a fiber, It can be preferably used in the field of films and other molded articles, particularly in the field of films where slipperiness and fineness of surface irregularities are strongly required.

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Claims (2)

[Claims] 1. A polyester composition containing silicon dioxide having an average particle size of 0.01 to 2.0 .mu.m, which is obtained by reacting a dicarboxylic acid or its ester-forming derivative with ethylene glycol, wherein the sulfur atom-containing compound is sulfur. 10 to 20 for silicon dioxide in terms of atoms
A polyester composition characterized by containing 00 ppm. 2. When a polyester is produced by reacting a dicarboxylic acid or its ester-forming derivative with ethylene glycol, water of silicon dioxide having an average particle size of 0.01 to 2.0 μm or ethylene glycol sol and a sulfur atom-containing compound are added to sulfur. A method for producing a polyester composition, which comprises adding 10 to 200 ppm in terms of atoms based on silicon dioxide to a reaction system at any stage of a polyester production process.