JP4110635B2 - Capacitor exterior polyester film, condenser exterior polyester film laminate metal plate and condenser exterior polyester film laminate metal case - Google Patents

Description

【表２】

【表３】

なお、表中の記号は、次の通りである（数値は酸、グリコール成分の中のモル％）。
【００６４】
ＴＰＡ：テレフタル酸
ＩＰＡ：イソフタル酸
ＥＧ：エチレングリコール
ＤＥＧ：ジエチレングリコール
ＣＨＤＭ：シクロヘキサンジメタノール
ＮＤＣ：ナフタレンジカルボン酸
【００６５】
【発明の効果】
本発明のコンデンサー外装ケース用ポリエステルフィルムは、成形性、耐熱性、絶縁性に優れており、成形加工によって製造されるコンデンサー外装用ケースに好適に使用することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention is a polyester film laminated metal sheet for a polyester film and a condenser exterior case for capacitors exterior case, it relates to a polyester film-laminated metal case for capacitors exterior case.
[0002]
More particularly, moldability, heat resistance, is excellent in insulating properties, molded by polyester for a suitable condenser outer casing in a metal case for capacitors exterior produced films and capacitors exterior case for the polyester film laminated metal sheet, the condenser outer case The present invention relates to a polyester film laminated metal case.
[0003]
[Prior art]
Conventionally, as a method of covering a capacitor such as an electrolytic capacitor, a heat-shrinkable tube made of polyvinyl chloride is put on the capacitor and passed through a hot air oven to fit the capacitor case and form an insulating exterior. Yes.
[0004]
In recent years, a polyvinyl chloride film has a problem in environmental properties at the time of incineration because it contains a chlorine element, so that an alternative to other materials is desired.
[0005]
However, polyvinyl chloride heat-shrinkable tubes have excellent heat-shrinkability, insulation, heat resistance, and printability. Polyolefin heat-shrinkable tubes and polyester heat-shrinkable tubes have good fit and insulating properties with capacitor cases. However, the characteristics were insufficient.
[0006]
Furthermore, the method of covering the heat shrinkable tube over the condenser and passing it through a hot air oven to fit the condenser case and form an insulating exterior is not an efficient process in terms of productivity. Although a method of imparting insulating properties to itself is effective, there is a problem that the formability is insufficient with a material in which a biaxially stretched PET film or a biaxially stretched nylon film is bonded to a metal plate with an adhesive.
[0007]
[Problems to be solved by the invention]
An object of the present invention is to eliminate the above-mentioned problems of the prior art, and a polyester film for a capacitor outer case suitable for use as a capacitor outer case excellent in moldability, heat resistance, and insulation, and polyester film laminated metal sheet for capacitors outer case, is to provide a polyester film-laminated metal case for capacitors exterior case.
[0008]
[Means for Solving the Problems]
The object of the present invention is to contain polyester A containing 0.005 to 3% by weight of particles having a particle diameter of 0.01 to 5 μm and having a melting point of 200 to 280 ° C. as a main component, and an acid constituting the polyester. 80% by mole or more of the component is terephthalic acid and / or naphthalenedicarboxylic acid, the number of carboxyl terminal groups of the polyester is 40 equivalents / ton or less, and the amount of alkali metal is M in the catalyst metal contained in the polyester. (Total number of moles of alkali metal per ton of polyester), amount of alkaline earth metal N (total number of moles of alkaline earth metal per ton of polyester), amount of titanium, manganese, cobalt, and zinc L (polyester) The total number of moles of the metal per ton), and the amount of phosphorus is P (the number of moles of phosphorus element per ton of polyester) To, and satisfies the following formula 1, and to a polyester film for capacitors outer case, wherein the plane orientation coefficient is 0 to 0.15, further, is achieved by coating with the film .
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The polyester used in the present invention is a polymer composed of a dicarboxylic acid component and a glycol component, and the dicarboxylic acid component is not particularly limited. For example, isophthalic acid, terephthalic acid, phthalic acid, diphenyl-4,4 ′ -Dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, diphenoxyethane-4,4'-dicarboxylic acid, diphenylsulfone-4,4 ' -Dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, malonic acid, 1,1-dimethylmalonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, decamethylene dicarboxylic acid and the like can be mentioned. Of these dicarboxylic acids, terephthalic acid and naphthalenedicarboxylic acid are preferably used from the viewpoint of heat resistance and insulation.
[0010]
On the other hand, the glycol component is not particularly limited, but examples thereof include aliphatic glycols such as ethylene glycol, propanediol, butanediol, pentanediol, hexanediol and neopentyl glycol, and cyclohexanedimethanol. Examples thereof include aromatic glycols such as alicyclic glycol, resorcin, bisphenol A, and bisphenol S, diethylene glycol, and polyethylene glycol. Among these, ethylene glycol, propanediol, butanediol, cyclohexanedimethanol and the like are preferable in terms of imparting shrinkage.
[0011]
The polyester in the present invention is required to have a melting point of 200 to 280 ° C. in terms of heat resistance and moldability. Further, in terms of moldability, the melting point is preferably 200 to 260 ° C, particularly preferably 210 to 250 ° C.
[0012]
It is necessary that 80 mol% or more of the acid component constituting the polyester of the present invention is terephthalic acid and / or naphthalenedicarboxylic acid . Moldability, heat resistance, because the insulating property is good.
[0013]
In addition, the intrinsic viscosity of the polyester is preferably 0.5 to 1.5. In particular, the intrinsic viscosity is preferably 0.6 to 1.5 in applications where heat resistance and aging resistance are required. The polyester film for a capacitor outer case of the present invention needs to have a carboxyl terminal group number of 40 equivalents / ton or less in view of improving the insulating properties, heat resistance, and aging properties of the film. More preferably, it is 10-40 equivalent / ton, Most preferably, it is 10-38 equivalent / ton.
[0014]
Furthermore, in order to make the insulation of the film of the present invention particularly good, in the catalyst metal contained in the polyester, the amount of alkali metal is M (total number of moles of alkali metal per ton of polyester), the amount of alkaline earth metal Is N (total number of moles of alkaline earth metal per ton of polyester), the amount of titanium, manganese, cobalt and zinc is L (total number of moles of the metal per ton of polyester), and the amount of phosphorus is P (polyester) It is necessary to satisfy Formula 1 when the number of moles of phosphorus element per ton). Further, from the viewpoint of insulation, it is preferable that the value of {(M / 2) + N + L} / P in Formula 1 is 1.5 or less.
[0015]
0 ≦ {(M / 2) + N + L} / P ≦ 2 Equation 1
In producing the polyester of the present invention, conventionally used reaction catalysts and anti-coloring agents can be used. Examples of reaction catalysts include alkali metal compounds, alkaline earth metal compounds, zinc compounds, Examples of coloring inhibitors such as lead compounds, manganese compounds, cobalt compounds, aluminum compounds, antimony compounds, and titanium compounds include phosphorus compounds. Preferably, an antimony compound, a germanium compound, or a titanium compound is preferably added as a polymerization catalyst at any stage before the production of the polyester is completed.
[0016]
As such a method, for example, when a germanium compound is taken as an example, a germanium compound powder is added as it is, or, as described in Japanese Patent Publication No. 54-22234, a glycosylated starting material for polyester. -A method in which a germanium compound is dissolved and added to the component can be mentioned.
[0017]
Examples of the germanium compound include germanium dioxide, germanium hydroxide containing crystal water, or germanium alkoxide compounds such as germanium tetramethoxide, germanium tetraethoxide, germanium tetrabutoxide, germanium ethyleneglycoxide, germanium phenolate, germanium β -Germanium phenoxide compounds such as naphtholate, phosphorus-containing germanium compounds such as germanium phosphate and germanium phosphite, and germanium acetate. Of these, germanium dioxide is preferable.
[0018]
Although it does not specifically limit as an antimony compound, For example, antimony oxides, such as antimony trioxide, an antimony acetate, etc. are mentioned. The titanium compound is not particularly limited, but alkyl titanate compounds such as tetraethyl titanate and tetrabutyl titanate are preferably used.
[0019]
The polyester film for a capacitor outer case of the present invention is laminated on a metal plate, and when molded into a capacitor case, the moldability is good and the average particle size in the polyester is sufficient to ensure sufficient insulation. It is necessary to add 0.005 to 3% by weight of 0.01 to 5 μm particles. If the average particle size is too large, the insulating property tends to be lowered or defects in the capacitor outer film tend to occur.
[0020]
Furthermore, it is preferable that the surface centerline average roughness Ra of a film is 0.005-0.1 micrometer from the point of a moldability. In particular, the surface average roughness is preferably 0.01 to 0.06 [mu] m, and the maximum roughness Rt is preferably 0.1 to 2 [mu] m from the viewpoint of reducing particle dropout.
[0021]
Specifically, inorganic particles include wet and dry silica, wet silica, colloidal silica, aluminum silicate, titanium oxide, calcium carbonate, calcium phosphate, barium sulfate, alumina, mica, kaolin, clay, etc. From the viewpoint of formability, aluminum silicate, colloidal silica and the like are preferable.
[0022]
Moreover, various organic polymer particles can be used as the organic particles, but any type of particles may be used as long as at least a part thereof is insoluble in polyester. Moreover, various materials such as polyimide, polyamideimide, polymethyl methacrylate, formaldehyde resin, phenol resin, cross-linked polystyrene, silicone resin, a mixture thereof, and a copolymer resin can be used as the material for such particles. However, vinyl-based crosslinked polymer particles that have high heat resistance and can easily obtain particles having a uniform particle size distribution are particularly preferred.
[0023]
The polyester film according to the present invention is required to have a plane orientation coefficient of 0 to 0.15 in terms of heat laminating property with a metal plate and moldability. In particular, the plane orientation coefficient is preferably 0.01 to 0.15, more preferably 0.05 to 0.145, particularly in terms of formability, heat resistance, and impact resistance of the metal plate laminated with the film. Preferably it is 0.06-0.14. Here, the plane orientation coefficient is nMD for the longitudinal refractive index of the film, nTD for the width direction refractive index of the film, and nZD for the thickness direction refractive index of the film, and the plane orientation coefficient Fn = (nMD + nTD) / It is represented by 2-nZD.
[0024]
Furthermore, the thickness direction refractive index nZD is preferably 1.5 or more in terms of moldability, heat resistance, and aging resistance. In particular, it is preferably 1.51 or more and 1.55 or less for achieving both formability and aging resistance.
[0025]
The thickness of the film of the present invention is preferably 10 to 500 μm, more preferably 12 to 300 μm, in terms of formability after being laminated to a metal, heat resistance, and insulation.
[0026]
The method for producing the film in the present invention is not particularly limited. For example, after drying the polyester as necessary, it is supplied to a conventionally known melt extruder, extruded from a slit-shaped die into a sheet, There is a method in which an unstretched sheet is obtained by close contact with a casting drum by application or the like and cooling and solidifying.
[0027]
A method for obtaining a film having a target refractive index in the thickness direction by stretching and heat-treating the unstretched sheet in the longitudinal direction and the width direction of the film is particularly preferable in view of heat resistance and aging resistance. Preferably, the tenter method is preferred in terms of film quality. After stretching in the longitudinal direction, a sequential biaxial stretching method in which the film is stretched in the width direction, and a simultaneous biaxial stretching method in which the longitudinal direction and the width direction are stretched almost simultaneously. Is desirable. As a draw ratio, it is 1.5 to 4.0 times in each direction, Preferably it is 1.8 to 3.5 times. Either the stretching ratio in the longitudinal direction or the width direction may be increased or the stretching ratio may be the same. The stretching speed is desirably 1000% / min to 200000% / min, and the stretching temperature can be any temperature as long as it is not less than the glass transition temperature of the polyester and not less than the glass transition temperature + 80 ° C. A temperature of + 20 ° C to 60 ° C is preferred.
[0028]
Further, after this, the film is heat-treated, and this heat-treatment can be carried out by any conventionally known method such as heating on a heated roll. The heat treatment temperature can be any temperature of 120 ° C. or higher and 250 ° C. or lower, but is preferably 150 to 240 ° C. Moreover, although heat processing time can be made arbitrary, 0.1 to 60 second is preferable, More preferably, it is 1 to 20 second.
[0029]
The heat treatment may be performed while relaxing the film in the longitudinal direction and / or the width direction. Furthermore, re-stretching may be performed once or more in each direction, and then heat treatment may be performed.
[0030]
Further, it is preferable to further improve the adhesion by performing a surface treatment such as a corona discharge treatment on the film surface. At that time, the E value is preferably 5 to 50, more preferably 10 to 45. Here, the E value is the corona discharge treatment intensity, which is a function of the applied voltage (Vp), the applied current (Ip), the treatment speed (S), and the treatment width (Wt), and E = Vp × Ip / S X Wt.
[0031]
Various coatings may be applied to the film of the present invention, and the coating compound, method, and thickness thereof are not particularly limited as long as the effects of the present invention are not impaired.
[0032]
Further, it is preferable that the heat shrinkage rate when heat-treating the film at 150 ° C. for 30 minutes is 5% or less in order to improve the laminate property with the metal. Particularly preferably, it is preferably 4% or less.
[0033]
The metal plate used in the present invention is not particularly limited, but a metal plate mainly composed of a material selected from iron and aluminum is preferable in terms of formability.
[0034]
Furthermore, in the case of a metal plate made of iron, an inorganic oxide coating layer that improves adhesion and corrosion resistance on the surface, such as chromic acid treatment, phosphoric acid treatment, chromic acid / phosphoric acid treatment, electrolytic chromic acid treatment Further, a chemical conversion treatment coating layer represented by chromate treatment, chrome chromate treatment and the like may be provided. In particular, a chromium hydrated oxide of 6.5 to 150 mg / m ² is preferable as chromium in terms of metal chromium, and a malleable metal plating layer such as nickel, tin, zinc, aluminum, gun metal, brass, etc. may be provided. Good. For tin plating 0.5-15 / m ^2, it is preferable to have a plating amount when nickel or aluminum 1.8~20g / m ^2.
[0035]
Polyester film laminated metal plate for capacitor outer cases obtained by thermally laminating at least one side of a metal plate mainly composed of a material selected from iron and aluminum. A polyester film laminated metal plate for a capacitor outer case obtained by heat laminating on both surfaces of a metal plate mainly composed of a material selected from aluminum and steel is particularly preferred.
[0036]
A polyester film laminated metal case for a capacitor outer case obtained by molding a polyester film laminated metal plate is excellent in insulation, heat resistance and aging resistance and can be suitably used as a capacitor case. In that case, it is preferable to form by drawing or ironing, especially after laminating with a metal.
[0037]
As molding, it is preferable to mold into a case with a reduction rate of 1 to 70%, and a reduction rate of 10 to 60% is particularly preferable. Here, the reduction rate is represented by (Y−Z) / Y × 100 (%), where Z is the thickness after molding with respect to the thickness Y before molding.
[0038]
【Example】
Hereinafter, the present invention will be described in detail by way of examples. The characteristics were measured and evaluated by the following methods.
[0039]
(1) Polyester intrinsic viscosity Polyester was dissolved in orthochlorophenol and measured at 25 ° C.
[0040]
(2) Film surface orientation coefficient Sodium D-line (wavelength 589 nm) as a light source, using an Abbe refractometer, the longitudinal refractive index nMD of the film, the refractive index nTD in the width direction of the film, and the refractive index nZD in the thickness direction of the film The surface orientation coefficient Fn = (nMD + nTD) / 2-nZD was obtained.
[0041]
(3) Cut the cross section of the average particle diameter film to make an ultrathin section, take 10 to 50 photographs at a magnification of about 5000 to 20000 using a transmission electron microscope, and circle each particle dispersed in polyester The equivalent diameter was measured and the average particle diameter was determined.
[0042]
(4) Polyester carboxyl end-group polyester was dissolved in o-cresol / chloroform (weight ratio 7/3) at 100 ° C. for 20 minutes, and subjected to potentiometric titration with alkali.
[0043]
(5) Melting point of polyester After melting the polyester, it was cooled rapidly, measured with a differential scanning calorimeter (DSC2 type, manufactured by Perkin Elmer) at a heating rate of 10 ° C./min, and the melting point was determined from the melting peak.
[0044]
(6) Thermal shrinkage rate The shrinkage rate of a film treated in a hot air oven at 150 ° C. for 30 minutes was measured. It measured about the longitudinal direction and the width direction, and described the value of the longitudinal direction (the larger one).
[0045]
(7) Film surface roughness (centerline average roughness Ra, maximum roughness Rt)
The surface of the A layer was measured using a high precision thin film level difference measuring instrument ET-10 manufactured by Kosaka Laboratory. The conditions were as follows, and the average value of 20 measurements was taken as the value.
[0046]
・ Tip tip radius: 0.5μm
-Stylus load: 5mg
・ Measurement length: 1mm
・ Cutoff value: 0.08mm
The definitions of Ra and Rt are shown in, for example, “Measurement / Evaluation Method of Surface Roughness” by Jiro Nara (General Technology Center, 1983).
[0047]
(8) A film was laminated on both sides of a TFS (tin-free steel) steel plate (thickness 0.2 mm) heated at a moldability of 60 m / min, cooled with warm water at 60 ° C., and then molded with a drawing machine. Here, the temperature of TFS was set so that the plane orientation coefficient of the film was about 1/4 of the polyester film before lamination after the heat lamination. The film having a plane orientation coefficient of 0 before lamination was heat laminated at a temperature of melting point + 5 ° C. Thereafter, a laminated metal plate was molded at a reduction rate of 20% to prepare a capacitor exterior case. The case was filled with a 1% sodium chloride aqueous solution, and a voltage of 200 V was applied to the liquid and the film on the outer surface of the case to confirm the conductivity. 100 cases were confirmed and judged as follows.
[0048]
○: 98% or more passed △: 90% or more and less than 98% passed ×: Pass rate less than 90% (9) Heat resistance After applying heat at 200 ° C. for 10 minutes to the above case, impact was given with a punch, The case was filled with a 1% sodium chloride aqueous solution, and a voltage of 200 V was applied to the liquid and the film on the outer surface of the case to confirm the conductivity. 100 cases were confirmed and judged as follows.
[0049]
○: 98% or more passed △: 90% or more and less than 98% passed ×: Pass rate less than 90% (10) The metal plate was removed with an acid from the metal plate laminated with the insulating film, and the dielectric breakdown voltage of the film Was measured according to JIS C2318 (AC 60 Hz). The judgment criteria are as follows.
[0050]
○: 7 kV or more Δ: 5 kV or more and less than 7 kV ×: less than 5 kV Example 1
Transesterification and polymerization were carried out using dimethyl terephthalate and ethylene glycol as starting materials, a titanium compound catalyst, a germanium compound catalyst, and a phosphorus compound as a heat stabilizer. After the transesterification reaction, an ethylene glycol slurry containing 5% by weight of aluminum silicate particles having an average particle diameter of 0.8 μm was added, and the polyester was adjusted to contain 0.15% by weight. The obtained polyethylene terephthalate (intrinsic viscosity 0.64 dl / g, melting point 256 ° C., germanium element 40 ppm contained, M = 1, N = 0, L = 30, P = 25) was made into polyester A and sufficiently vacuum at 160 ° C. It was dried, melt-extruded at 280 ° C., and rapidly cooled and solidified on a cast while electrostatically applied with an electrode on a tape to obtain an unstretched film.
[0051]
This unstretched laminated film was simultaneously biaxially stretched at a temperature of 100 ° C. (stretching ratio: 2.8 times, stretching speed: 2500% / min) with a linear motor type simultaneous biaxial stretching machine, and relaxed at 180 ° C. The film was heat-treated at 5% for 3 seconds to obtain a 50 μm film.
[0052]
Tables 1 and 2 show the obtained film characteristics and the characteristics of the metal laminated steel sheet.
[0053]
As is clear from these tables, it was confirmed that all of the properties of formability, heat resistance, and insulation were excellent, and the heat resistance was particularly good.
[0054]
Example 2 , Comparative Example 4, Comparative Example 5, Example 3
A film was obtained by changing the polyester composition, catalyst, melting point, particles, plane orientation coefficient, and film thickness.
[0055]
In Example 2, copolymerized PET was used, and the resulting unstretched film was formed using a tenter-type sequential biaxial stretching machine. The conditions at that time are a longitudinal stretching temperature of 95 ° C., a longitudinal stretching ratio of 3.0 times, a transverse stretching temperature of 110 ° C., a transverse stretching ratio of 3.0 times, a heat treatment temperature of 175 ° C., and a relaxation of 3%. It was confirmed that the obtained film was excellent in all of the properties of moldability, heat resistance, and insulation. In particular, the moldability was good.
[0056]
In Comparative Example 4 , when the same film forming conditions as in Example 2 were taken and the carboxyl terminal group of the polyester was changed to 48 equivalents / ton, the heat resistance was slightly lowered.
[0057]
In Comparative Example 5 , an antimony catalyst (antimony metal amount: 100 ppm) was used, calcium acetate was used as the transesterification catalyst, {(M / 2) + N + L} / P was set to 2.3, and the intrinsic viscosity was 0.78. When a stretched film was formed, heat resistance and insulation were slightly lowered.
[0059]
In Example 3 , an aluminum plate (0.3 mm) was used instead of TFS in Example 1. As a result, good characteristics were obtained.
[0060]
Comparative Example 1
The catalyst and particle composition were changed, and the film was formed so that the plane orientation coefficient of the film was 0.16. The characteristics of the obtained film and laminated metal plate are as shown in Table 3, and the moldability, heat resistance, and insulation were greatly reduced.
[0061]
Comparative Example 2
An unstretched film was formed by changing the melting point, catalyst, and particle composition of the polyester. The obtained film and laminated metal plate properties are as shown in Table 3, and the moldability, heat resistance, and insulation were greatly reduced.
[0062]
Comparative Example 3
A film was formed in the same manner as in Comparative Example 1 except that 5% by weight of particles having an average particle diameter of 10 μm was added. The characteristics of the obtained film and laminated metal plate are as shown in Table 3, and the moldability, heat resistance, and insulation were greatly reduced.
[0063]
[Table 1]

[Table 2]

[Table 3]

In addition, the symbol in a table | surface is as follows (a numerical value is the mol% in an acid and a glycol component).
[0064]
TPA: terephthalic acid IPA: isophthalic acid EG: ethylene glycol DEG: diethylene glycol CHDM: cyclohexanedimethanol NDC: naphthalenedicarboxylic acid
【The invention's effect】
The polyester film for a capacitor outer case of the present invention is excellent in moldability, heat resistance, and insulation, and can be suitably used for a capacitor outer case manufactured by molding.

Claims (5)

The main component is polyester A containing 0.005 to 3% by weight of particles having a particle size of 0.01 to 5 μm and a melting point of 200 to 280 ° C.
80 mol% or more of the acid component constituting the polyester is terephthalic acid and / or naphthalenedicarboxylic acid,
In addition, the number of carboxyl terminal groups of the polyester is 40 equivalents / ton or less, and the catalyst metal contained in the polyester has an amount of alkali metal of M (total number of moles of alkali metal per ton of polyester), alkaline earth metal The amount is N (total number of moles of alkaline earth metal per ton of polyester), the amount of titanium, manganese, cobalt, and zinc is L (total number of moles of the metal per ton of polyester), and the amount of phosphorus is P ( The number of moles of phosphorus element per ton of polyester), the following formula 1 is satisfied:
And the plane orientation coefficient is 0-0.15, The polyester film for capacitor | condenser exterior cases characterized by the above-mentioned.
0 ≦ {(M / 2) + N + L} / P ≦ 2 Equation 1 2. The polyester film for a capacitor outer case according to claim 1, wherein the surface center line average roughness Ra of at least one surface of the film is 0.005 to 0.1. A polyester film laminated metal for a capacitor outer case, obtained by thermally laminating the film according to claim 1 or 2 on at least one surface of a metal plate mainly composed of a material selected from iron and aluminum. Board. The capacitor outer case according to claim 3 , wherein the film is obtained by heat laminating the film according to claim 1 or 2 on both surfaces of a metal plate mainly composed of a material selected from iron and aluminum. Polyester film laminated metal plate. A polyester film laminated metal case for a capacitor outer case, obtained by molding the polyester film laminated metal plate according to claim 3 or 4.