JPH01292059A - Polyester composition - Google Patents

Abstract

PURPOSE:To obtain a polyester composition suitable as a base film for video tapes, etc., having a few voids, excellent evenness, slipperiness, shaving resistance, etc., by blending a polyester with two kinds of polystyrene particles having specific thermal decomposition temperatures and specific particle diameters. CONSTITUTION:A polyester comprising a bifunctional acid component (e.g., terephthalic acid) consisting essentially of an aromatic dicarboxylic acid and one or more glycol components (e.g., ethylene glycol) is blended with (A) 0.001-2wt.%, preferably 0.005-1wt.% crosslinked polystyrene particles having 0.1-0.6mum, preferably 0.25-0.5mum m average particle diameter and >=380 deg.C thermal decomposition temperature and (B) 0.001-2wt.%, preferably 0.005-1wt.% crosslinked polystyrene particles having 0.6-2mum, preferably 0.6-1.5mum average particle diameter and >=380 deg.C thermal decomposition temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a polyester composition, and more specifically, a polyester composition having a specific thermal decomposition temperature and containing crosslinked polystyrene particles having different average particle sizes. relating to things.

[Prior Art] Polyester, particularly polyethylene terephthalate, has excellent physical and chemical properties and is therefore widely used as fibers, films, and other molded products. In particular, polyester films are used for magnetic tapes, capacitors, photographs, packaging, OHPs, and the like.

In polyester films, their slipperiness and abrasion resistance are major factors that determine the workability of the film manufacturing process and processing process in each application, as well as the quality of the product. If these are insufficient, for example, when applying a magnetic layer to the surface of a polyester film and using it as a magnetic tape, the friction between the coating roll and the film surface during application of the magnetic layer will be intense, and this will cause severe wear on the film surface, resulting in extreme wear. In such cases, wrinkles, scratches, etc. may occur on the film surface. Furthermore, even after the film is coated with a magnetic layer and processed into audio, video or computer tapes, etc.
When pulling out reels, cassettes, etc., winding them up, and other operations, significant wear occurs between the guide parts, playback heads, etc., resulting in scratches, distortion, and even scratches on the surface of the polyester film. As a result of depositing powdery substances, it often becomes a major cause of missing magnetic recording signals, that is, dropouts.

Generally, to improve the slipperiness of a film, a method is adopted in which the surface of the film is made uneven to reduce the contact area between the film and guide rolls, etc.
(2) A method in which inert fine particles are precipitated from a polymeric catalyst residue used as a film raw material, and (2) a method in which inert inorganic fine particles are added. Generally speaking, the larger the size of the fine particles in these raw polymers, the greater the effect of improving slipperiness. Since this itself can cause defects such as dropouts, the unevenness on the film surface needs to be as fine as possible, and there is currently a demand to satisfy these contradictory characteristics at the same time.

Furthermore, in a film made of polyester containing the above-mentioned inert fine particles, peeling occurs at the boundary between the fine particles and the polyester due to biaxial stretching, and voids are formed around the fine particles. As these voids get larger, the shape of the protrusions becomes gentler, increasing the coefficient of friction, and small scratches on the voids of the biaxially oriented polyester film that occur during repeated use can also cause particles to fall off. This reduces durability and causes the generation of shavings.

It has traditionally been common practice to add one or more types (a combination of large particles and small particles) of calcium carbonate, titanium oxide, kaolin, colloidal silica, etc. as inert particles. The above-mentioned problem is inherent due to the formation of voids, and improvement of this problem is desired.

Therefore, the present inventors improved the above-mentioned drawbacks and improved the slipperiness and abrasion resistance of the film by reducing the voids around the particles and giving the film surface an appropriate roughness distribution. In addition, as a result of intensive studies to obtain a polyester film having surface properties suitable for various uses, the present invention was achieved.

[Problems to be Solved by the Invention] The object of the present invention is to contain cross-linked polystyrene particles having a specific thermal decomposition temperature and different average particle diameters, and especially when formed into a film, it has few voids, flatness, slipperiness, and resistance. An object of the present invention is to provide a polyester composition having excellent abrasion properties.

[Means for Solving the Problems] The object of the present invention described above is to provide a polyester comprising a bifunctional acid component mainly consisting of an aromatic dicarboxylic acid and at least one type of glycol component, which has an average particle size of 0.1 μm as a first component.
m or more and less than 0.6 μm and a thermal decomposition temperature of 380
A polyester composition containing crosslinked polystyrene particles having a temperature of 1.5°C or higher, and a second component containing crosslinked polystyrene particles having an average particle diameter of 0.6 μm to 260 μm and a thermal decomposition temperature of 380°C or higher. achieved by.

The difunctional acid component of the polyester of the present invention is mainly an aromatic dicarboxylic acid or an ester-forming derivative thereof, and specifically, terephthalic acid, 2,6-naphthalene dicarboxylic acid, 1,2-bis (2-chlorophenoxy)ethane-4,4'-dicarboxylic acid, its ester-forming derivatives include dimethyl terephthalate, dimethyl 2,6-naphthalenedicarboxylate, 1,2-bis(2-chlorophenoxy)ethane-4 , 4-dicarboxylic acid dimethyl, etc., among which terephthalic acid or dimethyl terephthalate is preferred.Glycol components include ethylene glycol, butylene glycol, diethylene glycol, propylene glycol, polyethylene glycol, and 1,4-cyclohexane dimetatool. Among them, ethylene glycol is preferred, and in addition to these dicarboxylic acids or their ester-forming derivatives and glycol components, other components may be copolymerized, such as diethylene glycol, propylene glycol, neopentyl glycol, etc. , polyalkylene glycol, p-xylylene glycol, 1,4-cyclohexane dimetatool, diol components such as 5-sodium sulforesorcin, adipic acid, sebacic acid,
Dicarboxylic acid components such as phthalic acid isophthalic acid, 2,6-naphthalene dicarboxylic acid, and 5-sodium sulfoisophthalic acid, polyfunctional dicarboxylic acid components such as trimellitic acid and pyromellitic acid, and oxydicarboxylic acid components such as p-oxyethoxybenzoic acid. Examples include acid components.

When the dicarboxylic acid component is a dicarboxylic acid, it is subjected to an esterification reaction with a glycol, and when it is a dicarboxylic acid ester, it is subjected to a transesterification reaction with a glycol, followed by polycondensation at high temperature and reduced pressure to obtain a polyester.

Moreover, polycondensation can also be carried out using the prepolymer itself as a starting material.

The crosslinked polystyrene particles used in the present invention are highly crosslinked polystyrene particles that have a thermal decomposition temperature (
In other words, in order for crosslinked polystyrene particles to function as a lubricant, they must have the heat resistance to not melt during polyester polymerization or at the melt molding temperature. be.

Preferably, the thermal decomposition temperature is 400°C or higher, more preferably 410°C or higher. If the thermal decomposition temperature is lower than 380° C., particle aggregation occurs during polyester polymerization or melt molding, resulting in poor lubricity.

In order to have such heat resistance, it is necessary to highly crosslink with divinylbenzene, etc., and it is preferable to use 12% by weight or more of pure divinylbenzene, more preferably 30% by weight or more, and more preferably 30% by weight or more based on the monomer. Preferably it is 50% by weight or more.

The crosslinked polystyrene particles used in the present invention preferably have a spherical shape and a uniform particle size distribution from the viewpoint of slipperiness and abrasion resistance.

That is, the volume shape coefficient is preferably 0.35 to 0.52, and more preferably 0.45 or more [However, the volume shape coefficient f is expressed by the following formula. f=V/D
3. Here, ■ is the particle volume (μm3), D is the maximum diameter of the particle in the projected plane (μm)], and L is the particle volume (μm3).
In the method of pulverizing and making fine particles, which is disclosed in Japanese Patent No. 5-158937, the particle shape is irregular and it is difficult to obtain a uniform particle size distribution. This is undesirable because it sometimes clogs the filter, impairs the flatness and abrasion resistance of the product, and causes dropouts.

As the crosslinked polystyrene particles of the present invention, those obtained by known manufacturing methods can be used. Known manufacturing methods include, for example, the following emulsion polymerization method.

(1) Soap-free polymerization method, that is, a method in which polymerization is performed without using an emulsifier or using a very small amount of an emulsifier.

(2) A seed polymerization method in which polymer particles are added to the polymerization system prior to emulsion polymerization and emulsion polymerization is carried out.

(3) A core-shell polymerization method in which a part of the monomer components is emulsion polymerized and the remaining monomers are polymerized within the polymerization system.

(4) JP-A-54-97582 and JP-A-Sho. 5
Polymerization method by Nigelstad et al. shown in Japanese Patent No. 4-126288.

(5) A polymerization method that does not use a swelling aid in the method (4) above.

Among the above methods, methods (3) and (4) are particularly preferred because they can yield spherical crosslinked polystyrene particles having a uniform particle size distribution.

The crosslinked polystyrene particles of the present invention each have an average particle size of 0.
．． 1 μm or more and less than 0.6 μm, preferably 0.2 μm or more and less than 0.6 μm, more preferably 0.25 μm or more and less than 0.5 μm, and an average particle size of 0.6 μm to 2 μm.
m, preferably 0.6 μm to 1.5 μm. If the average particle diameter of the crosslinked polystyrene particles as the first component is less than 0.1 μm, the slip property improving effect will be insufficient, which is undesirable; if it is 0.6 μm or more, the surface flatness will be insufficient, which is , the average particle size of the crosslinked polystyrene particles as the second component is 2.0μ
If it exceeds m, the surface flatness and abrasion properties will be insufficient, which is not preferable.

In the present invention, the amount of crosslinked polystyrene particles added as the first component is 0°001 to 2% by weight based on the polyester.
is preferable, and more preferably 0.005 to 1% by weight. The amount of crosslinked polystyrene particles added as the second component is preferably 0.001 to 2% by weight, more preferably 0.005 to 1% by weight, and preferably less than the weight of the first component. .

When the crosslinked polystyrene particles of the present invention are made of two components, the crosslinked polystyrene particles have good particle size uniformity and affinity. As a result, the flatness, slipperiness, and abrasion resistance can be satisfied.

Furthermore, in order to further improve the affinity with polyester, it is more preferable to introduce a group capable of reacting with polyester to form a covalent bond into the crosslinked polystyrene particles.
Examples include carboxyl groups, hydroxyl groups, sulfonic acid groups, ester groups, etc. It is preferable to use methacrylic acid for introducing carboxyl groups, acrylic monomer for hydroxyl groups, and styrene sulfonic acid for sulfonic acid groups. Yes, but not particularly limited. The amount of monomer for introducing these active groups is preferably 1 to 10% by weight based on the particles.

In addition, for the purpose of improving the heat resistance of the crosslinked polystyrene particles, S i 02, T i
It may be coated with an inorganic substance such as 02.

The two-component crosslinked polystyrene particles of the present invention can be added to and mixed with polyester by various known methods.

Among them, it is particularly preferable to add particles from before the start of polyester polymerization to during the polymerization reaction from the viewpoint of particle dispersibility.Addition of particles in the precursor stage or polycondensation stage before manufacturing the polyester composition is preferably carried out as an ethylene glycol slurry. The slurry concentration is preferably 0.
Approximately 5 to 20% by weight is appropriate.

For dispersion in a dispersion medium such as ethylene glycol, a high-speed dispersion machine, a sand mill, a roll seal, etc. may be used, for example.

In addition, during dispersion, phosphorus atom-containing compounds such as phosphoric acid and sodium hexametaphosphate, nitrogen atom-containing compounds such as tetraethylammonium hydroxide and hydroxylamine, alkali compounds, cations, anions, amphoteric or nonionic surfactants, or Use of a dispersant such as a water-soluble polymer further improves the dispersibility of crosslinked polystyrene particles in the slurry and polymer, and is particularly preferred.

In addition, lithium, sodium, calcium, magnesium, manganese, which are commonly used in the production of polyester,
A metal compound catalyst such as a compound such as zinc, antimony, germanium, or titanium, a phosphorus compound as a coloring inhibitor, inorganic particles other than crosslinked polystyrene particles, and organic polymer fine particles can also be added as appropriate.

[Example] The present invention will be explained in detail by giving examples below.

Incidentally, each characteristic value of the obtained polyester was measured according to the following method.

(A) Particle size The average particle size is determined from the particle equivalent spherical diameter at the 50 volume % point measured by electron microscopy of the particle.6 Equivalent spherical diameter is the diameter of a sphere that has the same volume as the particle. It is.

(B) Pyrolysis of Particles A thermobalance weight loss curve was measured using an electric TAS-100 under a nitrogen atmosphere at a heating rate of 20°C/lin. The 10% weight loss temperature was defined as the thermal decomposition temperature.

(C) Intrinsic viscosity of polymer 2 using 0-talolophenol as a solvent Measured at 5°C.

(D) State of particle dispersion in polymer After the polymer was cut into ultra-thin sections of approximately 800 slices using an ultra-thin film production device, the state of particle dispersion in the polymer was observed using a transmission electron microscope.

Determine the distributed state as follows. Ta.　　.

○: Almost no secondary agglomerated particles are observed, and the objective is achieved.

Δ: A slight amount of secondary agglomerated particles are present, and the purpose is not achieved.

×: Since most of the particles are secondary agglomerated particles, the purpose is not achieved.

(E) Film properties (1) Surface roughness Ra (μm) Measured using a stylus surface roughness meter according to J I 5-B-0601 (cutoff value 0.08+u+, measurement length 4 stops) ).

(2) Sliding property (coefficient of friction, μk) The film was slit into 1/2 inch pieces, and was measured at 20°C1 using a tape runnability tester model TBT-300 (manufactured by Yokohama System Research Institute Co., Ltd.).
The vehicle was run in a 60% RH atmosphere, and the initial μk was determined using the following formula.

μ=0.733 log (TI/T2) where T2 is the inlet tension and T1 is the outlet tension. The guide diameter is 6nIφ, the force guide material is 5US27 (surface roughness 0.2S), and the winding angle is 18mm.
0°, travel speed is 3.3>/sec.

A material having the above μk of 0.35 or less has good slip properties. Here, μk of 0°35 is a critical value that determines whether the slipperiness becomes extremely poor during film processing or when used as a product.

(3) Using an abrasion tape runability tester TBT-300 (manufactured by Yokohama System Research Institute Co., Ltd.), at 25°C,
After repeatedly traveling 300 times in an atmosphere of 0RH, white scraping powder (white powder) adhering to the guide portion was visually determined.

Here, the guide diameter is 8I11φ, and the guide material is 5
US27 (Surface roughness 0.2S), wrapping angle is 180
°, the tape running speed is 3.3 aa/sec. The evaluation criteria are as follows.

◎: The amount of white powder generated is very small, and the purpose Achieve.

○: The amount of white powder generated is small, achieving the purpose do.

△: The amount of white powder generated is slightly large, and the purpose was not achieved. Not accomplished.

X: The amount of white powder generated is very large. not achieved.

(4) A 15μ thick biaxially oriented film stretched at a void stretching ratio of 3.4 times in the vertical direction and 3.6 times in the horizontal direction at a stretching temperature of 90 to 100°C was mounted on a slide glass with liquid paraffin, and a transmission type Using the head W1 mirror as a dark field, measure the area A of the high brightness area (white area) using an image analyzer (QT).
M900, manufactured by Cambridge Instrument Co.).

Next, using a phase contrast microscope, the area B of the high brightness area and the low brightness area (gray to black area) in the same location was determined using an image analyzer in the same manner as above.
/A) was taken as the void ratio.

The evaluation criteria are as follows.

void ratio ◎: Achieve the objective with less than 0.1.

○: Achieved the purpose with less than 0.13 to 0.1 to be accomplished.

△: Achieved the objective with 0.2 to 0.13 do not have.

Go beyond X2O,2 and do not achieve the purpose.

Example 1 From 100 parts by weight of dimethyl terephthalate and 70 parts by weight of ethylene glycol, 0.09 parts by weight of calcium acetate! 1 part by weight of antimony trioxide, 0.3 part by weight of trimethyl phosphate, and 5% by weight of ethylene glycol slurry dispersed in the product. Cross-linked polystyrene particles with an average particle size of 0.3 μm at a temperature of 420°C (volume shape coefficient 0.51 > 0.5 parts by weight) and cross-linked polystyrene particles with an average particle size of 0.6 μm at a thermal decomposition temperature of 420°C (volume shape coefficient 0.50) 0.02 parts by weight was added and polymerized by a conventional method to obtain polyethylene terephthalate with an intrinsic viscosity of 0.615 and a softening point of 260.2°C.The inside of the polymer was observed using a transmission electron microscope. As a result, the particles were dispersed in a monodispersed state with little secondary aggregation.

The polymer was melt-extruded at 290° C., wound around a casting drum with a surface temperature of 30° C. using an electrostatic casting method, and cooled and solidified to obtain an unstretched film with a thickness of about 150 μm. This unstretched film was stretched 3.4 times in the longitudinal direction at 90°C and 3.6 times in the transverse direction at 100°C. Thereafter, it was heat-set at 210° C. to obtain a biaxially stretched film with a thickness of 15 μm. As a result of evaluating the film properties, it was found that the film had good flatness, slipperiness, and abrasion resistance (Table 1).

Examples 2 to 4, specific axis Examples 1 to 4 Polyethylene was prepared in the same manner as in Example 1 by changing the particle composition, thermal decomposition temperature, and average particle size of the crosslinked polystyrene particles (all have a volume shape coefficient of 0.51). A biaxially oriented film of terephthalate was prepared. When the crosslinked polystyrene particles contained within the particle composition, thermal decomposition temperature, and average particle size were within the range of the present invention, when made into a film, the flatness, slipperiness, and abrasion resistance were all different (Example 2~ 4).

However, if the thermal decomposition temperature and average particle size of the crosslinked polystyrene particles are outside the scope of the present invention, or if crosslinked polystyrene particles made of a single component are used, it is impossible to satisfy flatness, slipperiness, and abrasion resistance. (Comparative Examples 1 to 4).

Comparative Examples 5 to 7 Biaxially oriented films of polyethylene terephthalate were prepared in the same manner as in Example 1 using inorganic particles as the particles contained. None of them could satisfy flatness, slipperiness, and abrasion resistance.

[Effects of the Invention] Since the polyester of the present invention contains crosslinked polystyrene particles consisting of two components having a specific thermal decomposition temperature and a specific particle size, it exhibits the following excellent effects.

(1) The crosslinked polystyrene particles of the present invention have an affinity for polyester and are excellent in particle size uniformity, and when made into a film by making it into a two-component system, it has uniform uneven surface characteristics, excellent slipperiness, and abrasion resistance. A film having the following properties is obtained. Such a film is suitable as a base film for magnetic recording such as video, audio, and computer applications.

(2) The two-component crosslinked polystyrene particles of the present invention have excellent affinity with polyester, have few voids when made into a film, have excellent slipperiness due to uniform uneven surface characteristics, and have excellent transparency and electrical properties. . Such films are suitable for photography, plate making, and capacitor applications.

Claims (1)

[Claims] A polyester consisting of a bifunctional acid component mainly consisting of an aromatic dicarboxylic acid and at least one type of glycol component has an average particle size of 0.1 μm or more and less than 0.6 μm and a thermal decomposition temperature of 380° C. or more as the first component. containing crosslinked polystyrene particles having an average particle size of 0 as a second component.
．． 6 μm to 2.0 μm and thermal decomposition temperature of 380°C
A polyester composition containing the above crosslinked polystyrene particles.