JPH0116412B2 - - Google Patents

Description

[Detailed description of the invention]

(a) Technical Field The present invention relates to a technology for improving polyester films, and in particular to a polyester film with improved adhesiveness and mechanical performance, and a technology for producing the same. (b) Prior art Biaxially oriented films made of polyethylene terephthalate as a base polymer have superior heat resistance, gas barrier properties, electrical properties, and chemical resistance compared to other resin films, and have been used for various purposes. It is used. However, in fields such as magnetic tape, further improvements in performance in terms of mechanical strength and elastic modulus are required for the purpose of miniaturization and weight reduction. Furthermore, since the surface of polyester film is highly crystal oriented, it has high surface cohesion and poor receptivity to paints, adhesives, and inks, and there is a strong demand for improvements in adhesion. . (c) Purpose The present invention was made against the background of the above circumstances, and its purpose is to provide a polyester film that has higher strength, higher elastic modulus, and adhesive properties than conventional polyester films. An object of the present invention is to provide an improved polyester film. (d) Structure of the Invention As a result of intensive studies to achieve the above object, the present inventor has discovered that a polyester composition containing ethylene terephthalate as a main repeating unit and a specific aliphatic dicarboxylic acid has significantly improved strength. It was discovered that a biaxially stretched film having elastic modulus and adhesiveness can be provided, and the present invention was achieved. That is, the present invention provides (1) a polyester having ethylene terephthalate as a main repeating unit, in which at least one aliphatic dicarboxylic acid represented by the following general formula () is used as an acid component constituting the polyester;
A biaxially oriented polyester film comprising a polyester composition containing a polyester composition in a proportion of 0.1 to 10 moles per 100 moles. [In the formula, R is an alkylene group represented by CnH ₂ n (n is an integer of 10 to 18) or a group in which at least a part of the hydrogen atoms of the alkylene group is substituted with another group. (2) A polyester having ethylene terephthalate as a main repeating unit, in which at least one aliphatic dicarboxylic acid represented by the above general formula (I) is an acid component constituting the polyester.
It includes the step of melt-extruding a polyester composition containing 0.1 to 10 moles per 100 moles to form a film (sheet-like material), and then biaxially orienting the obtained unstretched film (sheet-like material). A method for producing a polyester film. The present invention will be explained. The polyester to which the present invention can be applied is mainly polyethylene terephthalate consisting of a terephthalic acid component and an ethylene glycol component, but a part of the terephthalic acid component (usually 15 mol% or less, preferably 10 mol% or less) is Even if the polyester is substituted with a difunctional carboxylic acid component, a portion of the ethylene glycol component (usually 15
It may be a polyester in which mol % or less, preferably 10 mol % or less) is replaced with another diol component. Furthermore, various additives, such as dyeing agents, flame retardants,
It may be a polyester copolymerized or mixed with an antistatic agent, a hydrophilic agent, a coloring agent, etc. as necessary. Such polyesters are usually produced by esterifying terephthalic acid and ethylene glycol, by transesterifying a lower alkyl ester of terephthalic acid such as dimethyl terephthalate with ethylene glycol, or by reacting terephthalic acid with ethylene oxide. The first step is to obtain a glycol ester of terephthalic acid and/or a low polymer thereof, and the second step is to perform a deglycol reaction from the glycol ester of dicarboxylic acid or a low condensate thereof to obtain a high molecular weight polyester. It consists of stages of reaction. The polyester composition constituting the film of the present invention can be obtained by adding a specific amount of a specific dicarboxylic acid, which will be described later, during the polyester production process. At this time, the timing of adding the dicarboxylic acid is not particularly limited. By adding a dicarboxylic acid at any point in the polyester production step, a filmable polyester composition can be produced that can have improved mechanical properties and adhesion, which are the objectives of the present invention. However, depending on the timing of addition of the dicarboxylic acid, the degree of manifestation of the two effects of high strength/high Young's modulus and improvement of adhesive properties differs. If high strength and high Young's modulus are particularly required, it is preferable to add it between the start of the first stage of polyester production and the beginning of the second stage reaction, and if particularly required to improve adhesion, it is preferable to add it during polyester production. It is preferable to add it in the latter half of the second stage reaction. When a part of the added dicarboxylic acid component is incorporated inside the polyester molecular chain, it contributes to high strength and high Young's modulus, and when the dicarboxylic acid is located at or near the end of the molecular chain, it improves adhesiveness. It seems to contribute to this, but the exact cause is unknown. In the present invention, the dicarboxylic acid to be added is important, and those represented by the following general formula are used. [In the formula, R is an alkylene group represented by CnH ₂ n (n is an integer of 10 to 18), or a group in which at least a part of the hydrogen atoms of the alkylene group is substituted with another group. ] Examples of such dicarboxylic acids in which R is an alkylene group include the following compounds. HOOC- (CH ₂ ) ₁₀ -COOH (dodecanedicarboxylic acid) HOOC- (CH ₂ ) ₁₄ -COOH (tetradecanedicarboxylic acid) HOOC- (CH ₂ ) ₁₈ -COOH (octadecanedicarboxylic acid) In addition, R is hydrogen of an alkylene group At least some of the atoms are replaced by other groups, such as aromatic groups, alkyl groups,
Examples of substituted with halogen etc. etc. can be mentioned. In the present invention, the amount of the dicarboxylic acid added to the polyester is 0.1 to 10 mol, preferably 0.3 to 5 mol, per 100 mol of the acid component constituting the polyester. If the amount exceeds 10 moles, the regularity of the polyethylene terephthalate molecules will be inhibited, resulting in poor properties such as heat resistance of the film, which is not preferable. In addition, the amount added is 0.1 per 100 moles of acid component.
If the amount is less than 1 molar, no effect of improving the adhesiveness or mechanical strength of the film will be observed. The method for producing a polyester film of the present invention includes adding a dicarboxylic acid at any stage or a specific stage of the polyester production process according to the method described above, and producing a polyester composition including a case where a very small amount of copolymerization is carried out. Step of forming this polyester composition into a sheet-like material using known melt extrusion means (extruder and film-forming die); Cooling of a casting drum etc. to rapidly cool and solidify the sheet-like material in the molten state. Stretching process in which an unstretched sheet-like material (film) is stretched sequentially or simultaneously to several times its original length in the longitudinal and width directions; Biaxial stretching at a temperature of about 150 to 250°C a step of heat treating the oriented film, and
It consists of a winding process in which a film that has been subjected to stretching orientation, crystallization heat treatment, and sulfurization is wound into a shape such as a roll. The method for producing the polyester film of the present invention can be carried out by combining generally known techniques, except for the step of preparing the polyester composition. The production method of the present invention has no particular difference in conditions compared to the production method of ordinary polyester films that do not contain any dicarboxylic acid. (E) Effects of the Invention The biaxially oriented polyester film obtained by the method of the present invention has high strength and high modulus of elasticity, and has improved adhesiveness, so compared to conventional polyester films, it has It has a wide range of uses and its effects are remarkable. (F) Examples The present invention will be explained in further detail with reference to Examples below.
Note that the measurement items in the examples were measured by the following methods. 1 Tensile test Tensilon UTM- manufactured by Toyo Baldwin Co., Ltd.
500 type, room temperature (20~25℃), relative humidity 55~
At 65%, the original film is 10 cm long and 1 cm wide.
Tensile at 100%/min and work on the load-elongation chart to find the following values. Breaking strength: The force required to break a film is expressed as the force (Kg/cm ² ) applied per unit cross-sectional area of the original film. Young's modulus: In a load-elongation chart, draw a tangent to the load-elongation curve at the load rise position, and calculate from the slope of this tangent. 2 Adhesion Magnetic paint is coated on polyester film under specified conditions, and Scotch tape is applied.
NO600 (manufactured by Yury M) Width 19.4m/m, Length 8
Adhere the cm so that there are no air bubbles, and then
Level it with a manual load roll as described in JIS C ₂₇₀₁ (1975), and use Tensilon UM- manufactured by Toyo Baldwin Co., Ltd. to adjust the head speed between 5 cm of the bonded laminated part.
This sample is T-peeled at 300 mm/min, the peel strength at this time is determined, and this is divided by the tape width to determine g/cm. In the T-peel, the laminate was placed with the tape side facing down and the distance between the take-off chucks was 5 cm. [Preparation and coating of magnetic paint for evaluation] Nitrocellulose in Lutzker thinner for paint
Dissolve RS1/2 [manufactured by Blakes Daicel Co., Ltd. containing 25% isopropanol] to prepare a 40ωt% solution,
Add 43.9 parts of this solution, followed by 32.5 parts of polyester resin (Telephene #1700 manufactured by Bayer), 200 gr of chromium dioxide magnetic powder, soybean oil fatty acid (manufactured by Resion P Riken Vitamin Co., Ltd.) as a dispersant and wetting agent, and cationic active. 1 part, 0.5 part, and 0.8 part of squalene (shark liver oil) (Cation AB, manufactured by Nippon Oil & Fats Co., Ltd.)
part into a ball mill. Mixed solution consisting of methyl ethyl ketone (hereinafter abbreviated as MEK)/cyclohexanone/toluene = 3/4/3 (weight ratio) 2.82
A mother liquor paint (45ωt%) is prepared by further mixing the remaining parts and sufficiently pulverizing the powder. For 50 parts of this mother liquor,
6.25 parts of butyl acetate was added to 48 parts of an addition reaction product of trimethylolpropane and toluleine diisocyanate (Coronate L, manufactured by Nippon Polyurethane Industries, Ltd.), to finally obtain a magnetic paint for evaluation having a concentration of 42.75 ωt%. The magnetic paint described above was dried on a polyester film at 80° C. for 1 minute, and then rolled coated so that the coating thickness after aging at 60° C. for 24 hours was 5 μm on average. Examples 1 to 3 and Comparative Examples 1 to 3 Polyethylene terephthalate was polymerized according to a conventional method using manganese acetate as a transesterification catalyst, antimony trioxide as a polymerization catalyst, and trimethyl phosphate as a heat stabilizer. At this time, polyethylene terephthalate was added during the transesterification reaction.
0.25 parts by weight of clay and dodecanedicarboxylic acid (see Table 1 for amounts added) were added to 100 parts by weight. The obtained polyethylene terephthalate with an intrinsic viscosity of 0.650 was dried, put into the popper of an extruder, melted at 300℃ for 5 minutes, extruded into a thin film through a die slit, and cast onto a cooling lawn whose surface temperature was maintained at 40℃. did. The thickness of the unstretched film after cooling was 350μ. 75 of the unstretched film
Longitudinal (MD) using rolls heated to °C
The film was stretched at a magnification of 3.7 times, then stretched in the width direction (TD) at a magnification of 4.0 times in a tenter heated to 110°C, and heat treated at 230°C for 5 seconds. The thickness of the biaxially oriented film thus obtained was 25μ. Table 1 shows the physical properties of these films.

[Table] It was observed that the addition of dodecanedicarboxylic acid at the proportion of the present invention significantly improved the strength and Young's modulus. Examples 4 to 6 and Comparative Examples 4 to 5 The same procedure as Examples 1 to 3 and Comparative Examples 1 to 3 was carried out except that dodecanedicarboxylic acid (see Table 2 for the amount added) was added in the latter half of the polycondensation reaction. A polyester film was obtained. Table 2 shows the physical properties of these films.

[Table] It is observed that the addition of dodecanedicarboxylic acid in the proportion of the present invention significantly improves adhesion. Examples 7 to 10 Dicarboxylic acids (see Table 3 for types and timing of addition)
Polyester films were obtained in the same manner as in Examples 1 to 3 and Comparative Examples 1 to 3, except that 1.0 mol/100 mol of DMT was added. Table 3 shows the physical properties of these films.

【table】

Claims (1)

[Claims] 1. A polyester containing ethylene terephthalate as a main repeating unit, which has the following general formula ()
At least one aliphatic dicarboxylic acid represented by
A biaxially oriented film made of a polyester composition containing a polyester composition in a proportion of 0.1 to 10 moles. [In the formula, R is an alkylene group represented by CnH ₂ n (where n is an integer of 10 to 18) or an alkylene group in which at least some of the hydrogen atoms are replaced with another group. ] 2 A polyester composition containing ethylene terephthalate as a main repeating unit, containing at least one aliphatic dicarboxylic acid represented by the above general formula () in a ratio of 0.1 to 10 moles per 100 moles of the acid component constituting the polyester. A method for producing a polyester film comprising the steps of melt-extruding and forming into a sheet-like product, and then biaxially stretching and orienting the sheet-like product.