JPS63118324A - Production of polyester containing silica alumina particle - Google Patents

Abstract

PURPOSE:To obtain the titled polymer having excellent surface flatness, surface slipperiness, abrasion resistance, etc., and suitable for fiber, etc., by adding silica alumina particles having a specific particle diameter, a phosphorus compound and an alkali metal compound, etc. in the form of a slurry to a polymerization system and carrying out the polymerization. CONSTITUTION:The objective polymer can be produced by compounding (A) 0.01-3.0pts.wt. (based on 100pts.wt. of polyester) of a silica alumina (e.g. kaolinite) having an average particle diameter of 0.02-5.0mu with (B) 0.01-40pts. wt. (based on 100pts.wt. of the component A) of a mixture of (i) a phosphorus compound (e.g. pyrophosphoric acid) and (ii) an alkali metal compound (e.g. sodium hydroxide), slurring the obtained mixture in e.g. glycol under ultrasonic vibration and adding the slurry to a polymerization system of polyethylene terephthalate. An alkali metal salt of a phosphorus compound (e.g. sodium pyrophosphate) may be used in place of the component B.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an improved method for producing polyester for producing films or fibers. In more detail, it is a method for producing linear polyester that can uniformly disperse silica-alumina particles in polyester to produce a film or fiber that has both surface flatness and surface slipperiness, and has excellent abrasion resistance. It is related to.

[Prior Art] Polyester, particularly polyethylene terephthalate, has excellent mechanical properties, heat resistance, weather resistance, and electrical insulation properties, and is therefore widely used as films, fibers, and other molded products.

However, when used by itself, the polyester decreases productivity due to poor process passability when forming a molded product, and when made into a biaxially stretched film, for example, its value is lost due to poor slipperiness of the film. There are problems such as

Conventionally, in order to solve this problem, inert inorganic particles such as calcium carbonate, titanium oxide, silicon oxide, etc. are included in the polyester to form irregularities on the surface of the molded product, thereby improving process passability during molding. There are known methods for imparting surface slipperiness to molded products. For example, Tokuko Sho 43-228
Japanese Patent No. 78 discloses a method for producing polyester with improved cooling properties by incorporating kaolinite as silica alumina.

However, since this kaolinite uses extremely fine particles of 10μ or less, it tends to aggregate, and as a result,
The increase in pressure when making films or fibers and the formation of coarse protrusions when making into products tend to cause particles to fall off or be scraped.Especially in applications such as magnetic tape, this can cause fish eyes (microscopic defects in the shape of fish eyes) and drops.・This can easily cause problems such as out <vii records.

For this reason, surface treatment agents such as quaternary ammonium compounds have been studied to increase the affinity between the precipitate-free particles and polyester, as seen in JP-A No. 51-68695. However, the improvement effect was not necessarily sufficient.

[Problems to be Solved by the Invention] The present inventors have discovered that the problem with the prior art is that the added silica alumina particles are not sufficiently dispersed and therefore contain a large number of coarse particles. Coarse particles have an effect on surface slipperiness, but when the polyester is formed into a film, the coarse particles often cause film tearing and increase in pressure, and in the formed film, fish eyes may occur. The present invention was arrived at as a result of intensive study on the issue of the occurrence of drop-outs.

That is, the object of the present invention is to provide a method for producing polyester, which has excellent surface properties such as surface flatness and surface smoothness when formed into a molded article, particularly a film, and which also has excellent abrasion resistance.

More specifically, it relates to a method for producing polyester that, when made into a film, has very small surface irregularities, has excellent surface slipperiness, and is free from defects such as film tearing, dropouts, and fish eyes.

[Means for solving the problem] The purpose of the present invention described above is to
Before the polymerization is completed, 0.01 to 40 ffiff 1 part (based on 100 parts by weight of silica alumina) of at least one of (A>phosphorus compound and alkali metal compound, or (B) an alkali metal salt of a phosphorus compound) is added. , 0.01 to 3.0 parts by weight (based on 100 parts by weight of polyester) of (C) silica alumina particles having an average particle size of 0.02 to 5.0 μ are added as a slurry, and then the polymerization is completed. This can be achieved by a method for producing polyester containing silica-alumina particles.

In the present invention, the phosphorus compound (A>) includes pyrophosphoric acid, metaphosphoric acid, phosphoric acid, phosphorous acid, hypophosphorous acid, etc., and among them, pyrophosphoric acid, metaphosphoric acid, phosphoric acid, etc. are preferable. It may be added alone, or
Two or more types may be used together. Alkali metal compounds include hydroxides and acetates of sodium, potassium, and lithium, among which sodium hydroxide, sodium acetate, potassium hydroxide, and potassium acetate are preferred, and sodium acetate and potassium acetate are more preferred. .

The alkali metal compounds of (B) phosphorus compounds include sodium pyrophosphate, potassium pyrophosphate, and sodium phosphate3. Potassium phosphate, sodium hexametaphosphate, etc. are preferred, among which sodium pyrophosphate, potassium pyrophosphate, sodium hexametaphosphate, etc. are preferred.

These compounds may be used alone, or two or more of these compounds may be used in combination.

Also, (A) a phosphorus compound and an alkali metal compound, and (B)
An alkali metal compound of the phosphorus compound may be used in combination.

These (A) phosphorus compounds and alkali metal compounds,
or (B) the alkali metal compound of the phosphorus compound needs to be added to the same slurry as the silica alumina particles in order to be used as a dispersant for the silica alumina particles. Examples of the slurry medium include water, methanol, ethylene glycol, 1,4-butanediol, neopentyl glycol, propylene glycol, diethylene glycol, etc., but it is preferable to use glycols used as polyester raw materials and copolymerization components. . Further, the slurry may contain a polyester catalyst, a heat stabilizer, an oxidative deterioration inhibitor, an ultraviolet absorber, a wax, and the like.

It is more preferable that the silica-alumina particle-containing slurry is added to the reaction system after being subjected to pretreatment such as mechanical dispersion using ultrasonic waves or high-speed stirring. In addition, the slurry
In order to achieve the desired particle size distribution, it may be filtered by a conventional method or classified using a decanter or the like. The addition time may be any time between the charging of the starting materials and the completion of the polymerization of the linear polyester, but it is preferably during esterification or after transesterification until the beginning of polycondensation.

In the present invention, the amount of (A>phosphorus compound and alkali metal compound, or (B) the alkali metal compound of the phosphorus compound added is 0.01 to 40 parts by weight of (A> or (B) to 100 parts by weight of silica alumina). It is preferably 0.05 to 20 parts by weight, and more preferably 0.1 to 10 parts by weight. If it exceeds 40 parts by weight, the polymerization time may be delayed or the polymer may deteriorate. This is not preferable because the intrinsic viscosity may become low.

On the other hand, if the amount is less than 0.01 part by weight, the desired dispersion effect of silica alumina will be insufficient, and coarse particles will be present in the polymer, resulting in breakage, dropouts, etc. when formed into a film. This is undesirable because it causes fish eyes, etc., and also causes thread breakage when made into fibers.

In addition, in order to prevent deterioration of the polymer due to the presence of a large amount of free metal ions, delay of polymerization time, or decrease in intrinsic viscosity due to excessive amount of residual phosphorus, the ratio of the phosphorus compound and the alkali metal compound (A>) should be The molar ratio of compound)/(alkali metal compound) is preferably 0.5 or more and 4.0 or less.

The silica-alumina particles in the present invention refer to a composite of silica and alumina, and include, for example, kaolinite, zeolite, and gicrite, among which kaolinite is preferred because of its excellent heat resistance.

The primary particle average diameter of silica alumina particles in the present invention needs to be 0.02 to 5.0 μm. Preferably 0
．． 05 to 3.0μ, preferably 0.1 to 3.0μ
It is 2.0μ.

If it exceeds 5.0μ, the surface flatness will be impaired when it is made into a film or fiber, the abrasion resistance will be lowered, and it will be a major cause of dropouts in the case of a film and thread breakage in the case of fibers, which is not preferable. On the other hand, if it is smaller than 0.02μ, the surface lubricity is insufficient when made into films and fibers, and some agglomeration occurs in polyester, which is equivalent to the presence of coarse particles. This is undesirable because it causes dropouts in the case of film and thread breakage in the case of fibers.

Particle size according to the invention means the "equivalent spherical diameter" of the particles at 50% by weight of the total particles. The term "equivalent spherical diameter" as used herein means the diameter of a virtual sphere having the same volume as the target particle, and can be measured by a known method such as a normal sedimentation method or direct observation using an electron microscope.

In order to prevent film tearing and drop-out, the particle size distribution preferably does not contain particles of 10 μm or more and is sharp, does not contain particles of 5.0 μm or more, and 2.
It is particularly preferred that the volume content of particles with a size of 0 μ or more is 30% or less.

In the present invention, the amount of the silica alumina particles added to polyester is as follows:
It is necessary to set it as 0.01-3.0 parts by weight. Preferably, if the surface flatness is less than 0.05 to 2 degrees, the film or fiber will have less surface unevenness and sufficient surface smoothness will not be obtained, which is not preferable.

The silica-alumina particle-containing slurry in the present invention can be added to known polyester. Such polyesters may be of any type as long as they can be formed into films or fibers, such as polyethylene terephthalate, polytetramethylene terephthalate, polycyclohexylene dimethylene terephthalate, polyethylene-2,6-naphthalene dicarboxylate, polyethylene -1,2-bis(2-(,)-chlorophenoxy)ethane 4,4-dicarboxylene]
・ etc. are preferably mentioned, and polyethylene terephthalate is particularly preferable.

These polyesters contain adipic acid, isophthalic acid, sebacic acid, phthalic acid, 4,4-
- Dicarboxylic acids such as diphenyldicarboxylic acid and their ester-forming derivatives, dioxy compounds such as polyethylene glycol, diethylene glycol, hexamethylene glycol, neopentyl glycol, polypropylene glycol, and oxidants such as p-(β-oxyethoxy)benzoic acid Carboxylic acids and their ester-forming derivatives may be copolymerized.

The polyester in the present invention can be synthesized by a known method. For example, in the case of polyethylene terephthalate, the polyester can be obtained by reacting Mi terephthalate or dimethyl terephthalate with ethylene glycol to form a low polymer, followed by polycondensation. At this time, known metal compounds such as acetates, oxalates, halides, and hydroxides of calcium, magnesium, lithium, manganese, zinc, and cobalt are used as transesterification reaction catalysts, and antimony compounds and hydroxides are used as polymerization catalysts. Titanium compounds, germanium compounds, etc. may also be used. In addition, known phosphorus compounds such as phosphoric acid, phosphorous acid, phosphonic acid and their lower alkyl esters and phenolic esters may be added as a coloring preventive agent in addition to the above (A>) during the reaction. do not have.

[Example] The present invention will be described in detail below with reference to Examples. In addition, the physical properties in Examples were measured as follows.

A. Average particle diameter of secondary particles The slurry containing inorganic particles was measured by a conventional liquid phase sedimentation method.

B. Friction coefficient of film The tension on both sides of the metal guide was measured while the film was running, and the dynamic friction coefficient was determined, which was used as a measure of surface slipperiness.

C. Roughness of film surface irregularities The film surface was observed using a microscope light wave interferometer, and the difference between the highest and lowest parts of the surface irregularities obtained was expressed in μ units.

D. Fish eye of the film When the film is observed under a polarizing microscope, the presence of primary particle aggregates of 5μ or more in the polarized area is considered a fish eye, and 'Icr? The number per r is expressed.

E. Wear-resistant film is slit into thin strips, then placed on a winder, rubbed against a metal guide rail installed in the middle, and run at high speeds. Indicated.

Rank A: Almost no white powder is generated.

B: A small amount of white powder is generated.

C: Metal guide rail fill the entire area on the contact surface side. White powder is attached.

F. Color tone of polymer was measured in chip form using a continuous color difference meter (Suga Test Instruments Co., Ltd.), and was expressed as a value and b value.

Example 1 90 parts of ethylene glycol and 0.2 parts of potassium pyrophosphate were added to 10 parts of kaolinite whose primary particles had an average diameter of 0.8 μm, stirred at high speed, and filtered through a 5 μm filter to prepare a slurry.

Next, 1 to 100 parts of dimethyl terephthalate, 70 parts of ethylene glycol, and 0.06 parts of magnesium acetate were charged, and after transesterification was carried out in the usual manner, 0.03 parts of trimethyl phosphate was added, and then the above-mentioned After adding 30 parts of the slurry, a usual polycondensation reaction was carried out to obtain a polymer having an intrinsic viscosity of 0.615 and a softening point of 260.8°C. The color tone of the polymer was good with a b value of 5.0 and an a value of -3°0.

Using the obtained polyester composition, the stretching ratio lengthwise was 3.3.
Double, width 3.5 times, heat treatment temperature 215°C1 heat treatment time 5
It was formed into a biaxially stretched film with a thickness of 10 μm under conditions of 10 seconds. The coefficient of dynamic friction of the obtained film was 0.24, the roughness of the film surface unevenness was 0.025μ, and the fish eye was O.
It was found that there was almost no adhesion of N/QTf N white powder, and that it had surface smoothness, uniform fine surface irregularities, and excellent abrasion resistance that were sufficiently satisfactory for magnetic tape applications.

Examples 2 to 6 As shown in Table 1, polyester compositions were prepared in the same manner as in Example 1 by changing the types of silica-alumina particles, the amount of particles added, the average particle diameter, and the type and amount of dispersant. An axially stretched film was obtained.

The obtained film had the physical properties shown in Table 1, and had sufficient surface slipperiness, uniform and fine surface irregularities, and abrasion resistance to be used as a magnetic tape.

Example 7 10 parts of kaolinite whose primary particles have an average diameter of 0.7μ, 90 parts of ethylene glycol, and pyrroline It! 0.15 parts,
After adding 0.33 parts of potassium acetate and stirring at high speed, 5μ
A slurry was made by filtering through a filter.

A polyester composition and a biaxially stretched film were obtained using this slurry in the same manner as in Example 1. As shown in Table 1, the obtained film had sufficient surface slipperiness, uniform fine surface irregularities, and abrasion resistance to be used as a magnetic tape.

(The following is a blank space) Comparative Examples 1 to 5 1 q of polyester compositions and biaxially stretched films were prepared in the same manner as in Example 1 except that the average diameter and amount of particles added and the type and amount of dispersant added were changed.

Table 2 shows the coefficient of dynamic friction, surface roughness, fish eye, and If abrasion resistance of the obtained film. As is clear from this table, even though the obtained biaxially stretched film has no uniform fine surface irregularities and has excellent surface slipperiness, it rarely has many fish eyes or poor abrasion resistance. However, it did not have sufficient performance for magnetic tape applications.

Furthermore, when the amount of the phosphorus compound added is large, the polymerization time is delayed and breakage occurs during film formation, making it impossible to obtain a satisfactory stable product.

(The following is a blank space) [Effects of the Invention] As described above, the present invention uniformly disperses fine silica alumina particles in polyester, so when it is made into a molded product, it has uniform and fine surface irregularities, It is possible to make a molded product that has both surface flatness and surface slipperiness, and also has excellent wear resistance.

Therefore, the composition of the present invention is effective in the fields of films, fibers, and other engineering plastics, and can be particularly preferably used in the field of films.

Claims (1)

[Claims] When producing polyester, (A
) a phosphorus compound and an alkali metal compound, or (B) an alkali metal salt of a phosphorus compound.
．． 01 to 40 parts by weight (to 100 parts by weight of silica alumina) and 0.01 to 3.0 parts by weight (to 100 parts by weight of polyester) of (C) silica alumina particles with an average particle size of 0.02 to 5.0 μ. 1. A method for producing a polyester containing silica-alumina particles, the method comprising: adding silica-alumina particle-containing polyester as a slurry, and then completing the polymerization.