JP2818371B2 - Polyester composition and polyester film - 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 a polyester film containing silicone resin fine particles dispersed therein, and more particularly, to a method of dispersing silicone resin fine particles well in polyester, which is flat and excellent in slipperiness and abrasion resistance. The present invention relates to a polyester composition suitable for producing a biaxially oriented polyester film and a biaxially oriented polyester film formed from the polyester composition.

[0002]

2. Description of the Related Art Biaxially oriented polyester films represented by polyethylene terephthalate films have been widely used for various uses, particularly for magnetic recording media, because of their excellent physical and chemical properties.

[0003] In a biaxially oriented polyester film, its slipperiness and abrasion resistance are major factors that affect the quality of workability in the film manufacturing and processing steps, and further, the product quality. If these are insufficient, for example, when a magnetic layer is applied to the surface of a biaxially oriented polyester film and used as a magnetic tape, friction and wear between the coating roll and the film surface are severe, and wrinkles and scratches on the film surface are likely to occur. Also, when used for VTRs and data cartridges, friction occurs between many guides, reproducing heads, etc. during pulling out, winding up, and other operations from cassettes, etc., causing scratches, distortion, and base film. The generation of white powder due to surface shaving or the like often causes a drop-out.

Many studies have been made on these problems, and among them, the method of adding fine particles of silicone resin (for example, Japanese Patent Application Laid-Open No. 62-172131) has a large improvement effect, and is expected to develop as a technology in the future. You.

[0005] However, even in the case of the same type of silicone resin fine particles to be added, even in such a method, there is a possibility that there is a slight difference in the expected slipperiness and abrasion resistance depending on the lot, depending on the lot. For example,
Even if the sliding property is good, the abrasion resistance is deteriorated, or a completely opposite phenomenon occurs.

[0006] Further, when collecting both ends of the film once formed into a film and mixing a part of the film with a new polymer for reuse, depending on the lot of the silicone resin fine particles used, the slip property and the abrasion resistance may be reduced. A new phenomenon appears that changes significantly.

[0007]

SUMMARY OF THE INVENTION The present inventors have conducted intensive studies to develop silicone resin fine particles capable of stably satisfying both the slipperiness and the abrasion resistance of such a film. It has been found that stable dispersibility and abrasion resistance can be obtained by dispersing and containing silicone resin fine particles having a small amount of Si dissolved in glycol in a polyester, and have reached the present invention.

[0008]

That is, the present invention relates to a method of preparing a silicone resin fine particle in an amount of 0.005 to 2 with respect to polyester.
In the polyester composition for the additional inclusion wt%, consists of polymethyl silsesquioxane having a crosslinking more than 80% by weight of the fine particles is represented by CH ₃ · SiO _3/2, soluble to glycol in the particulate A polyester composition characterized in that the amount of Si element is 2.5% by weight or less based on the total weight of the silicone resin fine particles, and a polyester film formed from the polyester composition.

The polyester in the present invention is a polyester containing an aromatic dicarboxylic acid as a main acid component and an aliphatic glycol as a main glycol component. Such polyesters are substantially linear and have film-forming properties, especially by melt-forming.
As the aromatic dicarboxylic acid, for example, terephthalic acid,
Examples thereof include 2,6-naphthalenedicarboxylic acid, isophthalic acid, diphenoxyethane dicarboxylic acid, biphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, diphenyl ketone dicarboxylic acid, and anthracene dicarboxylic acid. Examples of the aliphatic glycol include ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol,
Examples thereof include polymethylene glycol having 2 to 10 carbon atoms such as decamethylene glycol and alicyclic diols such as cyclohexanedimethanol.

In the present invention, polyesters containing alkylene terephthalate and / or alkylene naphthalate as a main component are preferably used.

Among such polyesters, particularly, polyethylene terephthalate (hereinafter sometimes referred to as “PET”), polyethylene-2,6-naphthalate (hereinafter “P”)
EN ”), for example, 80% by mole or more of the total dicarboxylic acid component is terephthalic acid and / or
Alternatively, a copolymer which is 2,6-naphthalenedicarboxylic acid and 80 mol% or more of the total glycol component is ethylene glycol is preferable. At that time, 20 mol% or less of the total acid component can be the above-mentioned aromatic dicarboxylic acid other than terephthalic acid and / or 2,6-naphthalenedicarboxylic acid,
Examples thereof include aliphatic dicarboxylic acids such as adipic acid and sebacic acid, and alicyclic dicarboxylic acids such as cyclohexane-1,4-dicarboxylic acid. In addition, 20 mol% or less of the total glycol component can be the above-mentioned glycol other than ethylene glycol. For example, aromatic diols such as hydroquinone, resorcinol, and 2,2-bis (4-hydroxyphenyl) propane;
Aliphatic diols having an aromatic ring such as 4-dihydroxydimethylbenzene; polyalkylene glycols (polyoxyalkylene glycols) such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol can also be used.

In the polyester of the present invention, a component derived from an oxycarboxylic acid such as an aromatic oxyacid such as hydroxybenzoic acid and an aliphatic oxyacid such as ω-hydroxycaproic acid may be used. Those which are copolymerized or bonded at 20 mol% or less based on the total amount of the acid component are also included.

In the present invention, the fine particles of the silicone resin contained in the polyester are CH ₃ .S
Particles of a silicone resin composed of an organopolysiloxane having a bonding unit represented by iO _3/2 of 80% by weight or more. The bonding unit has the following structural formula.

[0014]

Embedded image

In the silicone resin fine particles of the present invention, the amount of Si soluble in glycol needs to be 2.5% by weight or less, preferably 1.5% by weight, based on the silicone resin fine particles as a Si element. % Or less.
(The amount of glycol-soluble Si shown here is the amount of the Si element eluted in ethylene glycol when refluxing the ethylene glycol slurry having a silicone resin fine particle concentration of 2% by weight at the boiling point for 2 hours. Is expressed as% by weight based on the weight of the silicone resin fine particles.) When silicone resin fine particles having a Si content of more than 2.5% by weight as a Si element in glycol are used, a polyester film having stable slipperiness and abrasion resistance is obtained. I can't. The reason is that if the amount of Si soluble in glycol is large,
It is considered that the fine particles are softened by the heat received in the stage from the synthesis of the polyester to the formation of the polyester film.

In the silicone resin fine particles, the silanol group contained in the fine particles has a hydroxyl value of 50 KOH.
mg / g or less, more preferably 20 KOH mg / g or less. When the hydroxyl value exceeds 50 KOHmg / g, it is difficult to obtain a polyester film having stable slipperiness and abrasion resistance.

In order to obtain silicone resin fine particles having a reduced amount of glycol-soluble Si and silanol groups used in the present invention, the reaction for producing the silicone resin fine particles must be completed as much as possible. The effect of reliably performing the decomposition-condensation reaction is significant, and it can be achieved by performing more carefully the production process of the silicone resin fine particles, which includes aging and filtration and drying after the completion of the condensation reaction.

Further, the silicone resin fine particles in the present invention preferably have an average particle size of 0.1 to 3 μm,
More preferably, it is 0.3 to 2.0 μm. If the average particle size is less than 0.1 μm, it is difficult to improve the slipperiness and the abrasion resistance. On the other hand, if the average particle size exceeds 3 μm, it is difficult to obtain surface flatness, which is not preferable. In addition, it is preferable that the silicone resin fine particles have a spherical particle shape because they are effective for slipperiness.

In the present invention, the addition amount of the silicone resin fine particles must be 0.005 to 2% by weight based on the polyester. If the amount is too small, the lubricity becomes poor. If the amount is too large, problems such as insufficient dispersibility in the polymer arise.

In the present invention, the silicone resin fine particles may be used in combination with another lubricant. For example, scratch resistance, a combination with aluminum oxide or titanium dioxide or the like to improve the abrasion resistance, or in order to match the required film properties, calcium carbonate or silicon oxide, or any lubricant such as kaolin may be used in combination. Absent.

In the present invention, the timing at which the silicone resin fine particles are dispersed and contained in the polyester may be arbitrarily selected, but is preferably added during the polyester production step, more preferably before the transesterification reaction or before the esterification reaction and before the polycondensation reaction. I do.

In producing a film using the polyester composition of the present invention, a conventionally known method can be applied. For example, melt extruding polyester, cooling to obtain an unstretched film, and then stretching the unstretched film biaxially,
It can be produced by heat setting and, if necessary, heat treatment for relaxation. At this time, properties such as surface characteristics, density, and heat shrinkage of the film vary depending on stretching conditions and other manufacturing conditions, and are appropriately selected as necessary.

For example, the unstretched film may be uniaxially (longitudinal or transverse) [Tg-10] to [Tg + 6].
0] ° C. (Tg: glass transition temperature of polyester) at a magnification of 2.5 times or more, preferably 3 times or more, and then Tg to [Tg] in a direction perpendicular to the stretching direction.
It is preferable that the film is stretched at a temperature of +70] ° C. at a magnification of 2.5 times or more, preferably 3 times or more. Further, if necessary, the film may be stretched again in the machine direction and / or the cross direction. Thus, the total stretching ratio is preferably 9 times or more, more preferably 12 to 35 times, and more preferably 15 to 15 times, as the area stretching ratio.
25 times is particularly preferred. Furthermore, the biaxially oriented film can be heat-set at a temperature of [Tg + 70] ° C to [Tm-10] ° C (where Tm is the melting point of the polyester), for example, preferably 180 ° C to 250 ° C. The heat setting time is preferably 1 to 60 seconds.

[0024]

The present invention will be described in detail with reference to the following examples. The various physical properties and properties in the present invention are measured and defined as follows.

(1) Average particle size of particles (d) Centrifugal Particle S (Centrifugal Particle S) manufactured by Shimadzu Corporation
ize Analyzer). From the integrated curve of particles of each particle size and its abundance calculated based on the obtained centrifugal sedimentation curve, the particle size corresponding to 50 mass percent is read, and this value is defined as the average particle size (Book “Particle Size Measurement Technology Nikkan Kogyo Shimbun, 1975, pp. 242 to 247).

(2) Coefficient of running friction (μk) of the film Measured as follows using the apparatus shown in FIG.
In FIG. 1, 1 is an unwinding reel, 2 is a tension controller, 3, 5, 6, 8, 9, and 11 are free rollers, 4 is a tension detector (entrance), and 7 is stainless steel SUS3.
04 fixed rod (outer diameter 5 mmφ, surface roughness Ra = 0.0
2 μm), 10 is a tension detector (exit), 12 is a guide roller, and 13 is a take-up reel. At a temperature of 20 ° C. and a humidity of 60%, a film cut to a width of 1/2 inch is fixed to a fixing rod of 7 at an angle θ = (152/180).
Move (friction) at a speed of 200 cm per minute by contacting at π radians (152 °). Inlet tension T ₁ is 40
g when the tension controller 2 is adjusted so as to obtain the output tension (T ₂ : g).
After running, it is detected by an exit tension detector, and a running friction coefficient μk is calculated by the following equation (Equation 1).

[0027]

(Equation 1)

(3) Film surface roughness (Ra) This is a value defined by JIS-B0601 as the center line average roughness (Ra). In the present invention, a stylus type surface roughness meter manufactured by Kosaka Laboratory Co., Ltd. (SURFCORDER SE-30C). The measurement conditions are as follows. (A) Stylus tip radius: 2 μm (b) Measurement pressure: 30 mg (c) Cut-off: 0.08 mm (d) Measurement length: 1.0 mm (e) How to summarize data: Repeated measurement of the same sample 5 times , Except for one of the largest values, round the fifth digit after the decimal point of the average value of the remaining four data, and display up to the fourth digit after the decimal point.

(4) Abrasion resistance In the same apparatus as used in FIG. 1 used for measuring the running friction coefficient (μk), the winding angle was set to 30 degrees and the inlet tension was set to 50 g at a speed of 300 m / min. And run 200m. The shavings adhering to the fixed rod after running are evaluated according to the following criteria. <Determination of shavings> A: No shavings are observed. ：: Shaved powder is slightly observed. Δ: The presence of shavings can be seen at a glance. X: The shavings are badly adhered.

(5) Analysis of Amount of Si Element Soluble in Glycol An ethylene glycol slurry having a concentration of silicone resin fine particles of 2% by weight was refluxed and heated at the boiling point for 2 hours, and then centrifuged. Except for the resin fine particles, the Si component eluted in ethylene glycol
Quantitative analysis was performed by CP analysis, and the results are shown as weight percent of Si element with respect to the powder.

(6) Method of Measuring Hydroxyl Value Silanol groups in silicone resin fine particles were acetylated with acetic anhydride, and a certain amount of di-n-butylamine was added thereto to acetylate excess acetic anhydride. By titrating n-butylamine with HCl,
The amount of acetic anhydride consumed by the hydroxyl group is determined, and the hydroxyl value is determined by the following equation (Equation 2).

[0032]

(Equation 2)

A: Used amount of N / 2 HCl solution in this test (ml) B: Used amount of N / 2 HCl solution in blank test (ml) C: Potency of N / 2 HCl solution (KOH mg / ml) S: Sampling amount (g) (Reference J. Pharm. Sci., 66, 273 (1977))

(7) Glass transition temperature of polyester (T
g) Differential calorimeter manufactured by Dupont Instruments (Model 990 Thermal
Analyzer) at a rate of 20 ° C./min from room temperature, up to 290 ° C. if the polyester is PET,
In the case of PEN, the temperature is raised to 300 ° C., then rapidly cooled to 0 ° C., and the temperature is determined again from the temperature-differential calorific curve when the temperature is raised at a rate of 20 ° C./min.

(8) Melting point (Tm) of polyester Differential calorimeter (Model 990, manufactured by Dupont Instruments)
Using a temperature / differential calorie curve when the sample is heated from normal temperature at a rate of 20 ° C./min.

[Examples 1 to 6 and Comparative Examples 1 to 6] (1) Preparation of Glycol Slurry of Silicone Resin Fine Particles 95% by weight of CH ₃ .SiO _3/2 , average particle size of 0.
Using spherical silicone resin fine particles of 3 to 1.3 μm,
A 20% by weight ethylene glycol slurry was prepared for each. Tables 1 and 2 show the glycol-soluble Si content and the hydroxyl value of each silicone resin fine particle used at this time.

(2) Preparation of Polyester Composition Containing Silicone Resin Fine Particles Examples 1 to 5 and Comparative Examples 1 to 3, 5 and 6 used dimethyl terephthalate and ethylene glycol, and Example 6 and Comparative Example 4 used Dimethyl 2,2-naphthalenedicarboxylic acid and ethylene glycol, manganese acetate as a transesterification catalyst, antimony trioxide as a polymerization catalyst, phosphorous acid as a stabilizer, and (1)
The glycol slurries prepared in the above were added in amounts corresponding to the additions shown in Tables 1 and 2, and synthesized by a conventional method to obtain a polyester composition having an intrinsic viscosity (orthochlorophenol, 35 ° C) of 0.62. Among the polyester compositions, Examples 1 to
5 and Comparative Examples 1-3, 5, and 6 polyester (PET)
Is Tg 70 ° C., Tm 257 ° C., and the polyester (PEN) of Example 6 and Comparative Example 4 is Tg 120 ° C., Tm 267 ° C.
Met.

(3) Film formation of polyester composition When the polyester is PET, pellets of the polyester composition are dried at 170 ° C. for 3 hours, then supplied to an extruder hopper, and melted at a melting temperature of 280 to 300 ° C. This molten polymer was extruded through a 1 mm slit die onto a rotating cooling drum having a surface temperature of 20 ° C., and was rapidly cooled to obtain an unstretched film. The unstretched film thus obtained is preheated at 75 ° C., and further cooled between low-speed and high-speed rolls.
mm from above and stretched 3.6 times by heating with one IR heater with a surface temperature of 900 ° C, quenched, and then supplied to a stenter and stretched 3.7 times in the horizontal direction at 105 ° C. . The obtained biaxially stretched film was heat-set with 205 ° C. hot air for 5 seconds to obtain a heat-set biaxially oriented polyester film having a thickness of 15 μm.

When the polyester is PEN, pellets of the polyester composition are dried at 170 ° C. for 3 hours.
The molten polymer was supplied to an extruder hopper and melted at a melting temperature of 290 to 310 ° C. The molten polymer was extruded through a 1 mm slit die onto a rotating cooling drum having a surface temperature of 60 ° C, and rapidly cooled to obtain an unstretched film. The unstretched film thus obtained is preheated at 130 ° C., and is further heated at a surface temperature of 900 ° C. from 15 mm above between low-speed and high-speed rolls.
It was stretched 3.6 times by heating with one R heater, rapidly cooled, and then supplied to a stenter and stretched 3.7 times in the horizontal direction at 135 ° C. The obtained biaxially stretched film was
It was heat-set with hot air of 0 ° C. for 5 seconds to obtain a heat-set biaxially oriented polyester film having a thickness of 15 μm.

The properties of the obtained film are shown in Tables 1 and 2.

In Examples 1 to 6, the blending ratio of the silicone resin fine particles and the amount of glycol-soluble Si were within the range of the present invention, the running friction coefficient was as good as 0.19 to 0.20, and the abrasion resistance was good. Were all good. On the other hand, Comparative Example 1
In Nos. 4 to 4, the amounts of glycol-soluble Si were out of the range of the present invention, and the running friction coefficients were all as high as 0.23 to 0.24, the slipperiness was poor, and the abrasion resistance was poor. In Comparative Examples 5 and 6, the blending ratio of the silicone resin fine particles was out of the range of the present invention, and the slipperiness of the film or the dispersibility of the fine particles was poor.

[0042]

[Table 1]

[0043]

[Table 2]

[0044]

According to the present invention, it is possible to provide a polyester composition containing fine particles of silicone resin useful for the production of a polyester film having both excellent slipperiness and abrasion resistance, and a polyester film formed from the polyester. .

[Brief description of the drawings]

FIG. 1 is a schematic view of an apparatus for measuring a running friction coefficient (μk).

[Explanation of symbols]

 DESCRIPTION OF REFERENCE NUMERALS 1 unwinding reel 2 tension controller 4 tension detector (entrance) 7 fixed rod 10 tension detector (exit) 13 take-up reel

Claims (5)

(57) [Claims] 1. In a polyester composition containing 0.005 to 2% by weight of silicone resin fine particles based on polyester, 80% by weight or more of the fine particles contain CH ₃ .S.
It is made of polymethylsilsesquioxane having a cross-linking bond represented by iO _3/2 , and the amount of the Si element soluble in glycol in the fine particles is 2.5% by weight or less based on the total weight of the silicone resin fine particles. A polyester composition comprising: 2. The polyester composition according to claim 1, wherein the silanol group contained in the silicone resin fine particles has a hydroxyl value of 50 KOH mg / g or less. 3. The polyester composition according to claim 1, wherein the shape of the silicone resin fine particles is substantially spherical and the average particle size is 0.1 to 3 μm. 4. The polyester composition according to claim 1, wherein the polyester is a polyester containing alkylene terephthalate and / or alkylene naphthalate as a main repeating component. 5. A polyester film comprising the polyester composition according to claim 1.