JP3260881B2 - 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 polyester composition, and more particularly to a polyester composition containing calcium carbonate having a specific shape.
The present invention relates to a polyester composition exhibiting surface smoothness, abrasion resistance, and falling resistance, and capable of forming an excellent molded article without coarse projections.

[0002]

2. Description of the Related Art Polyesters, especially polyethylene terephthalate, have excellent physical and chemical properties.
Widely used as films, fibers and various molded products. In the film field, in particular, for magnetic tapes such as audio tapes and video tapes, packaging, agricultural use,
Various uses such as OHP are known, and in the field of textiles, they are used in large quantities for industrial use as rubber reinforcing fibers typified by tire cords, V-belts, and conveyor belts or for various types of clothing. I have. However,
Despite these excellent properties, undesired problems such as poor slipperiness in the molding process and the product itself to obtain the above molded product, and poor workability and reduced commercial value due to shavings and fallouts I have

[0003] Conventionally, as a method of lowering the coefficient of friction, which is a measure of poor slipperiness, fine particles are formed in a polyester or fine particles are blended in the polyester to give appropriate projections to the film surface. Therefore, it is common practice to improve the slipperiness. Examples of such fine particles include fine particles precipitated from a catalyst residue and the like during the production of polyester, and inorganic fine particles insoluble and inactive in polyester such as calcium carbonate, titanium dioxide, silica, talc, and kaolin. However, the method of incorporating these fine particles, on the other hand, impairs the surface smoothness of the film. In addition, the former method of precipitating fine particles has difficulty in controlling the amount and diameter of particles and is liable to be broken in the stretching step, so that satisfactory effects in running properties and abrasion resistance have not been obtained. In addition, in the case of the latter method of adding inorganic fine particles, the affinity between the fine particles and the polyester is not always sufficient, and voids are generated around the particles in the stretching step, and the generation of white powder due to damage to the film or fiber or falling off of the fine particles. Is causing the problem. Especially for magnetic tapes, in addition to the slipperiness, in response to recent demands for high quality, miniaturization and long-time recording, a thin film with a smooth surface and thickness is required, and surface smoothness, Abrasion resistance and shedding resistance are important characteristics.

Various attempts have been made to obtain a film satisfying all these characteristics. For example, JP
No. 0-1144 and JP-A-51-68695, a method of using a specific dispersant when preparing a glycol slurry, and a method of preparing a glycol slurry disclosed in JP-A-52-78953. A physical dispersion method for giving ultrasonic vibration when performing
JP-A-62-224331 discloses a method of blending two kinds of particles having a specific particle size distribution ratio when producing a polyester film disclosed in JP-A-62-232431. A method of blending fine particles containing an element having a distribution and a dispersing function can be used.

[0005] In particular, regarding the improvement of the affinity between the inorganic fine particles and the polyester, surface treatment with a polyacrylic acid polymer disclosed in JP-A-63-128031, JP-A-64-43537 and JP-A-64-43537 are disclosed. 4-298538
And surface treatment with a coupling agent disclosed in Japanese Patent Application Laid-Open Publication No. H11-157, and the like. On the other hand, as an example in which the chemical composition of the fine particles themselves is changed, calcium carbonate containing a phosphorus atom disclosed in JP-A-63-234039 or calcium element disclosed in JP-A-4-224861 is 5 to 40% by weight. % Wet-process silica particles. Also,
Examples in which the shape of the fine particles themselves are modified are, for example, an inert fine particle having three projections on the surface of JP-A-64-48835, and a nucleus on the surface of a particle serving as a nucleus of JP-A-3-70768. Composite particles coated with fine particles having an average diameter of 1/10 or less of the following, secondary particles having an average particle diameter of 0.03 to 3 μm combined with primary particles of Japanese Patent Publication No. Hei 4-25857 having a surface area of 250 m by the BET method. ² / g or more of silicon oxide particles.

[0006] However, none of these methods has provided satisfactory effects in all aspects of slipperiness, surface smoothness, abrasion resistance and shedding resistance. In recent years, despite the increasing demand for films having these contradictory surface properties, it has been considered extremely difficult to obtain films having such properties.

[0007]

In view of such circumstances, the present inventors have conducted intensive studies from the stage of synthesizing inorganic fine particles in order to solve the above-mentioned disadvantages of the prior art, and have found that the particle size distribution is sharp and polyester The calcium carbonate having good dispersibility in the film and less falling off from the film was successfully produced, and the present invention was achieved by adding and blending the calcium carbonate to a polyester.

[0008] That is, an object of the present invention is to provide a polyester composition excellent in slipperiness, surface smoothness, abrasion resistance and shedding resistance.

[0009]

The present invention solves the above-mentioned problems by solving the problem that the average primary particle diameter (d) is 0.005.
０．１0.10 μm, average particle diameter of major axis of secondary particles (D)
Is 0.05 to 5.0 μm, and the ratio (d / D) of the average particle diameter of the minor axis of the primary particles to the average particle diameter of the major axis of the secondary particles is in the range of 1/300 to 1/2. This problem has been solved by a polyester composition characterized in that calcium is contained in an amount of 0.005 to 5.0% by weight based on polyester.

In the present invention, the polyester is a polyester obtained by using an aromatic dicarboxylic acid as a main acid component and performing a polycondensation reaction with a glycol component. Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenylethanedicarboxylic acid, and the like. Examples of the glycol component include ethylene glycol, diethylene glycol, propylene glycol, tetramethylene glycol, and the like.
The most typical polyester is mainly composed of polyethylene terephthalate obtained by a polycondensation reaction of terephthalic acid and ethylene glycol as main monomer components.

One of the calcium carbonate fine particles having such characteristics, which is dispersed and contained in the polyester of the present invention, is disclosed in Japanese Patent Application Laid-Open No. 3-170327 filed by the present inventors.
There is a calcite-type spherical calcium carbonate obtained by a method of subjecting a spherical dry aggregate to a heat treatment in a carbon dioxide gas atmosphere according to the publication. According to this method, not only the primary particles can be freely selected, but also the secondary particle diameter can be controlled by changing the spray method, spray conditions, liquid concentration, and the like. Another one is crystalline calcium carbonate prepared by carbonation in an ethylene glycol system according to Japanese Patent Application No. 4-176948, also filed earlier. Since the crystalline calcium carbonate prepared by this method is obtained by crystallization in an ethylene glycol system, there is an advantage that it can be added as it is in the polyester production process.

In the present invention, in particular, the ratio of the average particle diameter of the minor axis of the primary particles to the average particle diameter of the major axis of the secondary particles (d / d)
D) has an important meaning. That is, d / D is 1/300 ~
It is desirable to be in the range of 1/2, further 1/100
The range of 範 囲 is desirable. If d / D is smaller than 1/300, the effect is reduced in terms of dropping, and if it is 1/2 or more, it is geometrically difficult. In the present invention, it is efficient to select or control the primary particle diameter so that d / D falls within the range of 1/300 to 1/2 according to the desired secondary particle diameter.

In the present invention, the calcium carbonate fine particles can be added to the polyester at any stage of the polyester production process, but the reaction is completed from the beginning of the esterification or transesterification reaction of the dicarboxylic acid component with the glycol. It is preferable to add at a stage until the prepolymer is obtained or at an initial stage of polycondensation of the prepolymer. In addition, the addition amount is 0.005 to 5.0% by weight, preferably 0.02%, based on the polyester.
~ 3.0% by weight. If the added amount is less than 0.005% by weight, the slipperiness of the film is insufficient, and if it exceeds 5.0% by weight, the surface smoothness, abrasion resistance and falling resistance are undesirably reduced.

The polyester composition of the present invention contains calcium carbonate having a secondary particle diameter of 0.05 to 5.0 μm and having surface irregularities developed, and has properties such as slipperiness and surface when formed into a film or fiber. In addition to improving smoothness, it also prevents the generation of white powder and reduced abrasion resistance due to falling off of particles, which is thought to be caused by voids due to stretching during molding, which was a problem when adding inorganic fine particles. This can solve problems such as deterioration in workability and reduction in product value. In addition, as long as the effect of the inorganic fine particles of the present invention is not impaired, inorganic or organic fine particles insoluble in polyester or fine particles precipitated in a reaction system during the production of polyester may be used in combination.

That is, the object of the present invention can be solved only by using calcium carbonate prepared by these methods, and a film or fiber excellent in slipperiness, surface smoothness, abrasion resistance and shedding resistance can be obtained. A molded polyester composition can be provided.

[0016]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples. The measurement of each characteristic in the present invention was performed by the following method.

(1) Particle size distribution (particle size measurement) The primary particle size was determined by a transmission electron microscope (TEM). Regarding the secondary particle diameter, a centrifugal sedimentation type particle size distribution analyzer SA-CP3 manufactured by Shimadzu Corporation was used.
In this case, an aqueous solution in which 0.2% by weight of sodium hexametaphosphate was dissolved in ion-exchanged water was used as a dispersion medium, and ultrasonic waves were irradiated for 5 minutes or more with occasional stirring as a preliminary dispersion to measure.

(2) Slippery The coefficient of static friction was measured in accordance with the ASTM-D-1894B method, and the values were ranked in three stages based on the values and used as a measure of slipperiness.

[0019]

[Table 1]

The smaller the value of the coefficient of friction, the better the slipperiness.

(3) Surface smoothness Measured using a Surfcom surface roughness meter according to JIS B0601. The center line average roughness (Ra) measured under the conditions of a needle diameter of 2 μm, a load of 70 mg, a measurement reference length of 0.25 mm, and a cutoff of 0.08 mm is indicated.

(4) Abrasion resistance When a tape-like roll in which a film is slit into a narrow width is rubbed against a stainless steel guide roll and run at high speed for a long time, the amount of white powder generated on the surface of the guide roll for a constant supply tension. Was rated and ranked on a five-point scale.

[0023]

[Table 2]

(5) Number of Coarse Protrusions on Surface After aluminum is thinly deposited on the surface of the film, the number of coarse protrusions of four or more rings (the number per 1 mm ^{2 of the} measurement area) is counted using a ^two- beam interference microscope. The number of projections was evaluated and ranked on a five-point scale.

[0025]

[Table 3]

Calcium carbonate A The lime milk having a quick lime concentration of 5% was carbonated with carbon dioxide by a conventional method to obtain an aqueous slurry of colloidal calcium carbonate having an average particle size of 0.08 μm. After diluting the slurry 5 times, it was spray-dried with a spray drier equipped with a two-fluid nozzle, and was directly dried in an atmosphere of 30% carbon dioxide gas.
Sintered at 00 ° C. The calcium carbonate spherical sintered body thus obtained was dispersed in ethylene glycol, and coarse particles were removed by classification to produce a calcium carbonate ethylene glycol dispersion having an average particle diameter of 0.45 μm.

The result of X-ray diffraction of the calcium carbonate powder before dispersion in ethylene glycol was consistent with the calcite pattern.

Calcium carbonate B Lime milk having a quick lime concentration of 5% was carbonated with carbon dioxide by a conventional method to obtain an aqueous slurry of colloidal calcium carbonate having an average particle size of 0.06 μm. After diluting the slurry 5 times, it was spray-dried with a spray drier equipped with a two-fluid nozzle, and was directly dried in an atmosphere of 30% carbon dioxide gas.
Sintered at 00 ° C. The calcium carbonate spherical sintered body thus obtained was dispersed in ethylene glycol, and coarse particles were removed by classification to produce a calcium carbonate ethylene glycol dispersion having an average particle size of 0.50 μm.

The result of X-ray diffraction of the calcium carbonate powder before dispersion in ethylene glycol was consistent with the calcite pattern.

Calcium carbonate C Lime milk having a quicklime concentration of 4% was carbonated with carbon dioxide by a conventional method to obtain an aqueous slurry of colloidal calcium carbonate having an average particle size of 0.02 μm. After diluting the slurry four-fold, it was spray-dried with a spray drier equipped with a two-fluid nozzle, and was directly dried in an atmosphere of 30% carbon dioxide gas.
Sintered at 00 ° C. The calcium carbonate spherical sintered body thus obtained was dispersed in ethylene glycol, and coarse particles were removed by classification to produce a calcium carbonate ethylene glycol dispersion having an average particle size of 3.80 μm.

The result of X-ray diffraction of the calcium carbonate powder before dispersion in ethylene glycol was consistent with the pattern of calcite.

Calcium carbonate D In the same manner as for calcium carbonate C, the average particle size is 0.48 μm.
m of ethylene carbonate dispersion of calcium carbonate was prepared.

670 g of calcined lime powder was added to 4 kg of calcium carbonate E ethylene glycol, stirred and then transferred to a stainless steel reaction vessel having a capacity of 30 liters, and 15 kg of ethylene glycol was further added to prepare a raw material slurry. At this time, the temperature of the slurry was 32 ° C.
pH was 11.4 and conductivity was 4.7 mS / cm.
A mixed gas with air having a carbon dioxide gas concentration of 30% by volume was introduced into the raw material slurry at a rate of 66.7 liter / min. During the carbonation process, the pH showed a substantially constant value, but the conductivity gradually decreased to 1.7 mS / cm, and after 40 minutes, the slurry gelled at a pH of 6.9. The temperature at that time is 42 ° C
Met. The whole amount of this gel was heated to 60 ° C. 2-3
Over time, the gel nearly collapsed and slurried again.

The calcium carbonate slurry which was allowed to stand for one day was designated as calcium carbonate E. A part of this slurry was filtered, washed with methanol, and dried at 110 ° C. The X-ray diffraction result of the powder matched the pattern of calcite. Also, T
The primary particle size observed by EM was about 0.01 μm, and the average particle size of the secondary particles was 1.21 μm.

1 kg of industrial slaked lime was added to 4 kg of calcium carbonate F ethylene glycol, stirred, transferred to a stainless steel reaction vessel having a capacity of 30 liters, and further added with 15 kg of ethylene glycol to prepare a raw material slurry. At this time, the temperature of the slurry was 30 ° C.
pH was 12.4 and conductivity was 3.3 mS / cm.
A gas mixture with air having a carbon dioxide gas concentration of 30% by volume was introduced into the raw material slurry at a rate of 66.7 liter / min. During the carbonation process, the pH showed a substantially constant value, but the conductivity gradually decreased to 0.8 mS / cm, and after 40 minutes, the slurry gelled at pH 8.0. The temperature at that time is 38 ° C
Met. The whole amount of this gel was heated to 60 ° C. 2-3
Over time, the gel nearly collapsed and slurried again.

The calcium carbonate slurry which had been allowed to stand overnight was classified to obtain calcium carbonate D. A part of this slurry was filtered, washed with methanol, and dried at 110 ° C. The X-ray diffraction result of the powder matched the pattern of calcite. The primary particle diameter observed by TEM was 0.01 μm
The average particle size of the secondary particles was 0.54 μm.

Calcium carbonate G 670 g of calcined lime powder was added to 4 kg of ethylene glycol, stirred and then transferred to a stainless steel reaction vessel having a capacity of 30 liters, and 15 kg of ethylene glycol was further added to prepare a raw material slurry. At this time, the temperature of the slurry was 34 ° C.
pH was 12.2 and conductivity was 3.8 mS / cm.
A gas mixture with air having a carbon dioxide gas concentration of 30% by volume was introduced into the raw material slurry at a rate of 66.7 liter / min. During the carbonation process, the pH showed a substantially constant value, but the conductivity gradually decreased to 0.8 mS / cm, and after 40 minutes, the slurry gelled at a pH of 7.2. The temperature at that time is 44 ° C
Met. The whole amount of this gel was heated to 60 ° C. 2-3
Over time, the gel nearly collapsed and slurried again.

The calcium carbonate slurry which had been allowed to stand overnight was classified to obtain calcium carbonate G. A part of this slurry was filtered, washed with methanol, and dried at 110 ° C. The X-ray diffraction result of the powder matched the pattern of calcite. The primary particle diameter observed by TEM was 0.01 μm
The average particle diameter of the secondary particles was 0.40 μm.

Comparative Sample A Spindle-shaped calcium carbonate having a major axis of 3.0 μm and a minor axis of 1.0 μm was stirred at a high speed with a homogenizer and uniformly dispersed in ethylene glycol to obtain Comparative Sample A.

Comparative Sample B A commercially available synthetic calcium carbonate having an average particle size of 0.50 μm was uniformly stirred in ethylene glycol by high-speed stirring with a homogenizer to obtain Comparative Sample B.

Comparative Sample C A commercially available synthetic calcium carbonate having an average particle size of 0.25 μm was stirred at a high speed with a homogenizer and uniformly dispersed in ethylene glycol to obtain Comparative Sample C.

Comparative Sample D A commercially available synthetic spherical silica having an average particle size of 0.30 μm was stirred at a high speed with a homogenizer and uniformly dispersed in ethylene glycol to obtain Comparative Sample D.

Comparative Sample E A commercially available synthetic silica having an average particle diameter of 0.28 μm was stirred at a high speed with a homogenizer and uniformly dispersed in ethylene glycol to obtain Comparative Sample E.

Comparative Sample F A commercially available synthetic titanium oxide having an average particle size of 0.25 μm was stirred at a high speed with a homogenizer and uniformly dispersed in ethylene glycol to obtain Comparative Sample F.

Comparative Sample G A commercially available synthetic titanium oxide having an average particle size of 0.21 μm was stirred at a high speed with a homogenizer and uniformly dispersed in ethylene glycol to obtain Comparative Sample G.

Example 1 Terephthalic acid was used as an acid component, and ethylene glycol was used as a glycol component. Calcium carbonate A was added to the solid content of 0.3% by weight and polycondensed by a conventional method to give an intrinsic viscosity of 0.62. A polyester containing calcium carbonate was obtained. The polyester is dried and extruded by a conventional method to obtain an unstretched sheet.
And subsequently stretched 3.8 times in the transverse direction at 115 ° C. Further, a heat treatment is performed at 210 ° C. for 10 seconds to obtain a thickness of 1
A 5 μm biaxially stretched polyester film was obtained.

Examples 2 to 7 The same as Example 1 except that calcium carbonate BG was used instead of calcium carbonate A.

Examples 8 and 9 In Example 2, the amount of calcium carbonate B added was set to 0.03 and 3.0% by weight in terms of solid content.

Examples 10 and 11 In Example 7, the amount of calcium carbonate G added was adjusted to 0.03 and 3.0% by weight in terms of solid content.

Comparative Examples 1 to 3 The same as the example except that comparative samples A to C (calcium carbonate) were used instead of calcium carbonate A.

COMPARATIVE EXAMPLE 4.5 Instead of adding 0.3% by weight of calcium carbonate A in solid content, comparative samples D to E (silica) were added in 0.23 in solid content.
Same as Example 1 except that weight% was added.

COMPARATIVE EXAMPLE 6.7 Instead of adding 0.3% by weight of calcium carbonate A in solid content, comparative samples FG (titanium oxide) were added in an amount of 0.3% in solid content.
Same as Example 1 except that 43% by weight was added.

Table 4 summarizes the measurement results for each item of the polyester films produced in the above Examples and Comparative Examples. It is clear from this table that Examples 1 to 11 are far superior to Comparative Examples 1 to 7 in not only slipperiness and surface smoothness but also abrasion resistance and the number of coarse protrusions.

[0054]

[Table 4]

[0055]

Industrial Applicability The polyester composition of the present invention contains calcium carbonate having a secondary particle diameter of 0.05 to 5.0 μm and having developed surface irregularities, and has a slipperiness when formed into a film or fiber. In addition to the improvement in surface smoothness, the generation of voids due to stretching during molding, which had been a problem when adding inorganic fine particles, was considered to be the cause. Can be prevented, and problems such as deterioration of workability and reduction of commercial value can be solved. Especially when used as a base film of a magnetic tape, it has an excellent effect.

────────────────────────────────────────────────── (5) References JP-A-60-197755 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 67/00-67/04

Claims (1)

(57) [Claims] An average particle diameter of the minor diameter of the primary particles is 0.00
5 to 0.10 μm, the average particle diameter of the major axis of the secondary particles is 0.05 to 5.0 μm, and the ratio of the average particle diameter of the minor axis of the primary particles to the average particle diameter of the major axis of the secondary particles, 1/300
A polyester composition comprising from 0.005 to 5.0% by weight of calcium carbonate in the range of from 〜 to に 対 し て.