KR101555808B1 - Flame-retardant biaxially-oriented polyester film - Google Patents

Abstract

There is provided a flame retardant biaxially oriented polyester film in which base layer itself of a polyester such as polyalkylene terephthalate or polyalkylene naphthalate is subjected to flame retardation with a phosphorus flame retardant and further suppressed in degradation of hydrolysis resistance by these flame retardants.
The present invention relates to a flame retardant biaxially oriented polyester film comprising a flame retardant base layer, wherein the flame retardant base layer comprises polyalkylene terephthalate or polyalkylene naphthalate in an amount of 60 wt% to 98 wt% , And a flame retardant biaxially oriented polyester film containing not less than 2% by weight and not more than 40% by weight of a specific phosphinic acid salt or diphosphonic acid salt.

Description

Flame-retardant biaxially oriented polyester film {FLAME-RETARDANT BIAXIALLY-ORIENTED POLYESTER FILM}

The present invention relates to a biaxially oriented polyester film having flame retardancy and, more particularly, to a biaxially oriented polyester film having excellent flame retardancy and excellent hydrolysis resistance compared with conventional flame retardant polyester films, ) And exhibits a high flame retardancy even when used as a flame-retardant biaxially oriented polyester film.

The biaxially oriented film of a polyester film, particularly polyethylene terephthalate or polyethylene naphthalate, has excellent mechanical properties, heat resistance, and chemical resistance, and therefore can be used as a magnetic tape, a photographic film, a packaging film, an electronic component film, And is widely used as a material for a protective film, a protective film, and a protective film.

In recent years, with the implementation of the Product Liability Law, flame retarding of resins is strongly desired in order to secure safety against fire.

Halogen-based flame retardants such as organohalogen compounds and halogen-containing organophosphorus compounds, which are conventionally used, have a high flame retardant effect, but they are free from halogen during molding and processing and generate corrosive halogenated hydrogen gas, And the possibility of deteriorating the work environment. It has been pointed out that the flame retardant may generate gas such as hydrogen halide during combustion such as fire. Therefore, it is strongly desired to use a halogen-free flame retardant instead of the halogen-based flame retardant recently.

Although various phosphorus compounds have been studied as one of the flame retardant agents containing no halogen-containing flame retardant, for example, when the flame retardant method using a phosphoric acid ester compound is added to a polyester in a large amount, Or the melting point is lowered.

As a method for smearing a polyester resin, a method of copolymerizing a phosphorus compound with a polyester has been studied. For example, in Japanese Patent Application Laid-Open No. 2007-9111 (Patent Document 1), a method of copolymerizing a carboxyphosphinic acid component It is disclosed that a high flame retardancy can be imparted to polyethylene-2,6-naphthalenedicarboxylate in a small amount without using other phosphorus compounds by using a specific carboxyphosphinic acid component. However, in the laminated film having a layer containing a carboxyphosphinic acid compound as in Patent Document 1, a high flame retardancy is exhibited in the film state, but when flame retardancy after film processing such as a flat cable is not reproduced .

As other phosphorus flame retardants, for example, JP-A-2009-179037 (Patent Document 2) and JP-A-2010-89334 (Patent Document 3) disclose phosphoric acid derivatives of inorganic metal such as phosphinic acid metal salts A laminated film obtained by laminating a flame retardant layer containing a polyester film on a polyester film. However, the proposed laminated film was a technique for forming a flame retardant layer using a flame retardant and a curing agent on the base film in view of the fact that the porous substrate film had a high combustibility due to the void structure inside the film. JP-A-2010-229390 (Patent Document 4) discloses a composition containing a phosphoric acid derivative of an inorganic metal and a flame-retardant coating wire, but it is a technique for flame-retarding a thermoplastic elastomer resin. The thermoplastic elastomer resin has an elongation , The lowering of the physical properties accompanying the addition of the flame retardant is not a serious problem.

As described above, even when the substrate layer itself of a polyester such as polyethylene terephthalate or polyethylene naphthalate is softened with a phosphorus flame retardant and is not accompanied by deterioration in the hydrolysis resistance caused by these flame retardants and is used in conjunction with a metal layer, A flame-retardant biaxially oriented polyester film showing the same high flame retardancy as the film has not yet been proposed.

Japanese Patent Application Laid-Open No. 2007-9111 Japanese Patent Application Laid-Open No. 2009-179037 Japanese Patent Application Laid-Open No. 2010-89334 Japanese Patent Application Laid-Open No. 2010-229390

It is an object of the present invention to overcome the problems of the prior art and to provide a method for producing a flame retardant which softens the substrate layer itself of a polyester such as a polyalkylene terephthalate or a polyalkylene naphthalate with a phosphorus flame retardant, Retarded biaxially oriented polyester film wherein the flame-retardant biaxially oriented polyester film is suppressed.

A second object of the present invention is to provide a flame retardant biaxially oriented polyester film excellent in flame retardancy, which is obtained by softening the base material layer of polyester itself with a phosphorus flame retardant and suppressing degradation of hydrolysis resistance by these flame retardants, .

A third object of the present invention is to provide a flame retardant resin composition which is excellent in flame retardancy 2 even when it is processed into a use in which the base material layer itself of the polyester is softened with a phosphorus flame retardant agent and the degradation of hydrolysis resistance by these flame retardants is suppressed, And a flame retardant biaxially oriented polyester film laminate which exhibits the same high flame retardancy as the axially oriented polyester film itself.

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that by using a phosphinic acid metal salt as a flame retardant component in a polyester film such as polyethylene terephthalate and polyethylene naphthalate, It was found that the addition of the phosphorus component in a large amount does not inhibit the hydrolysis resistance of the polyester.

On the basis of these findings, it is possible to add a large amount of a flame retardant component to the polyester base layer because of less effect of deterioration of physical properties on these polyesters as compared with the conventional phosphorus flame retardant agent, To obtain a flame retardant biaxially oriented polyester film, thereby completing the present invention.

That is, an object of the present invention is to provide a flame retardant polyester film comprising a flame retardant base layer, wherein the flame retardant base layer comprises a polyalkylene terephthalate or a polyalkylene phthalate in an amount of 60 wt% to 98 wt% And a flame retardant biaxially oriented polyester film (item 1) containing not less than 2% by weight and not more than 40% by weight of a phosphinic acid salt represented by the following formula (1) or a diphosphonic acid salt represented by the formula (2) .

[Chemical Formula 1]

(Wherein R ¹ and R ² are hydrogen, an alkyl group having 1 to 6 carbon atoms and / or an aryl group, M is a metal, and m is a valence of M)

(2)

(Wherein R ³ and R ⁴ represent hydrogen, an alkyl group and / or an aryl group having 1 to 6 carbon atoms, R ⁵ represents an alkylene group having 1 to 6 carbon atoms or an arylene group, an alkylarylene group or an arylalkylene group having 6 to 10 carbon atoms , M is a metal, and n is a mantissa of M)

The flame retardant biaxially oriented polyester film of the present invention also includes the following aspects as a preferred embodiment thereof. Further, the flame retardant biaxially oriented polyester film laminate having the flame retardant biaxially oriented polyester film of the present invention and a metal layer laminated thereon Are included in the present invention.

Item 2. The flame-retardant biaxially oriented polyester film according to Item 1, wherein the phosphorus atom concentration in the flame-retarded substrate layer is 1 wt% or more and 8 wt% or less based on the weight of the flame-retardant substrate layer.

Item 3. The flame-retardant biaxially oriented polyester film according to Item 1 or 2, wherein the thickness of the flame-retardant base layer is 2 μm or more and 200 μm or less.

Item 4. The flame-retardant biaxially oriented polyester film according to any one of items 1 to 3, wherein the polyester film has a tensile strength retention ratio of 50% or more after being treated in a saturated steam at 121 占 폚 and 2 atm for 10 hours.

Item 5. A flame-retardant biaxially oriented polyester film according to any one of Items 1 to 4, wherein an average reflectance of the polyester film at a wavelength of 400 to 700 nm is 75% or more and 100% or less.

6 wherein the film density of 0.7 g / ㎝ ³ more than 1.3 g / ㎝ ³ or less, wherein 1-5 of the flame-retardant biaxially oriented polyester film according to any one.

Item 7. A flame-retardant biaxially oriented polyester film according to any one of Items 1 to 6, wherein the surface roughness Ra of the flame retardant base layer is 0.1 占 퐉 or more and 2 占 퐉 or less.

Item 8. The flame-retardant biaxially oriented polyester film according to any one of items 1 to 7, which is used as a flexible printed circuit, a flat cable, a solar cell back sheet, or a reflector.

Item 9. The flame-retardant biaxially oriented polyester film according to any one of Items 1 to 8, which has a heat-seal layer on at least one side of the flame retardant base layer.

Item 10. A flame retardant biaxially oriented polyester film laminate obtained by laminating a flame-retardant biaxially oriented polyester film and a metal layer according to any one of items 1 to 9.

Item 11. A flame-retardant flat cable using the flame-retardant biaxially oriented polyester film according to any one of Items 1 to 9.

The flame-retardant biaxially oriented polyester film of the present invention has a high flame retardancy without deteriorating the hydrolysis resistance of polyesters such as polyalkylene terephthalate or polyalkylene naphthalate, and can be used as a flexible printed circuit board, Cable, solar cell back sheet or reflector.

Hereinafter, the present invention will be described in detail.

<Flame-retardant biaxially oriented polyester film>

The flame retardant biaxially oriented polyester film of the present invention is a flame retardant biaxially oriented polyester film comprising a flame retardant base layer, wherein the flame retardant base layer is a polyalkylene terephthalate or a polyalkylene naphthalate Of a flame retardant biaxially oriented polyester film containing not less than 60 wt% to not more than 98 wt% of a phosphinic acid salt represented by the following formula (1) or not less than 2 wt% and not more than 40 wt% of a diphosphonic acid salt represented by the formula (2) to be.

(3)

(Wherein R ¹ and R ² are hydrogen, an alkyl group having 1 to 6 carbon atoms and / or an aryl group, M is a metal, and m is a valence of M)

[Chemical Formula 4]

(Wherein R ³ and R ⁴ represent hydrogen, an alkyl group and / or an aryl group having 1 to 6 carbon atoms, R ⁵ represents an alkylene group having 1 to 6 carbon atoms or an arylene group, an alkylarylene group or an arylalkylene group having 6 to 10 carbon atoms , M is a metal, and n is a mantissa of M)

[Flame Retardant Substrate Layer]

The flame retardant base layer of the present invention contains polyalkylene terephthalate or polyalkylene naphthalate as a polymer component in a range of 60 wt% to 98 wt% with respect to the flame retardant base layer, The phosphinic acid salt represented by the formula (1) or the diphosphinic acid salt represented by the formula (2) is contained in the range of 2 wt% to 40 wt% with respect to the flame retardant base layer.

(Polyester)

As the polyalkylene terephthalate in the present invention, polyethylene terephthalate, polytrimethylene terephthalate and polybutylene terephthalate are exemplified, and among them, polyethylene terephthalate is preferable. As the polyalkylene naphthalate in the present invention, polyethylene naphthalate, polytrimethylene naphthalate and polybutylene naphthalate are exemplified. Of these, polyethylene naphthalate is preferable, and polyethylene-2,6-naphthalate is more preferable desirable.

The lower limit of the content of these polyesters is preferably 65% by weight based on the weight of the flame retardant base layer, more preferably 70% by weight, even more preferably 75% by weight, and most preferably 80% Particularly preferred.

The upper limit of the content of these polyesters is preferably 96% by weight, more preferably 94% by weight, still more preferably 90% by weight, particularly preferably 85% by weight in relation to the content of the flame- Weight%.

If the content of these polyesters is less than the lower limit, the film-forming composition of the film becomes insufficient. On the other hand, if the content of these polyesters exceeds the upper limit value, the content of the flame retardant component is relatively small.

The polyalkylene terephthalate or polyalkylene naphthalate of the present invention may be a copolymer having a component other than the main component (hereinafter sometimes referred to as a copolymerization component) within the range not hindering the object of the present invention, The copolymerization component can be used in an amount of less than 25 mol%, more preferably 20 mol% or less, further preferably 15 mol% or less based on the number of moles of all repeating units of these polyesters.

Examples of such a copolymerization component include oxalic acid, adipic acid, phthalic acid, sebacic acid, dodecanedicarboxylic acid, isophthalic acid, terephthalic acid, 1,4-cyclohexanedicarboxylic acid, 4,4'- Naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, tetralinedicarboxylic acid, decalindicarboxylic acid, diphenyl ether dicarboxylic acid Oxycarboxylic acids such as dicarboxylic acids such as acetic acid, dicarboxylic acids such as acetic acid and the like, p-oxybenzoic acid and p-oxyethoxybenzoic acid, and organic acids such as ethylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, cyclohexanedimethanol, , Ethylene oxide adducts of bisphenol sulfone, ethylene oxide adducts of bisphenol A, diethylene glycol, polyethylene oxide glycol and the like. Of these, components other than the main components can be preferably used. These copolymerization components may be used singly or in combination of two or more.

These copolymerization components may be copolymerized as a monomer component or may be copolymerized by transesterification reaction with another polyester.

The polyalkylene terephthalate or polyalkylene naphthalate of the present invention may be a blend of at least two kinds of polyester or a blend with a thermoplastic resin other than polyester within the range not hindering the object of the present invention. These other components can be used in an amount of not more than 20% by weight, more preferably not more than 15% by weight, further preferably not more than 10% by weight, based on the weight of the flame retardant base layer. As thermoplastic resins other than polyester, for example, polyolefin resins, polystyrene resins, polyimide resins and the like can be given.

The intrinsic viscosity of these polyesters is preferably from 0.4 dl / g to 1.5 dl / g, more preferably from 0.5 dl / g to 1.2 dl / g, as measured using an o-chlorophenol solvent at 25 ° C More preferable.

(Flame retardant component)

In the present invention, a phosphinic acid salt represented by the following formula (1) or a diphosphinic acid salt represented by the formula (2) is used as a flame retardant component. Hereinafter, they may be collectively referred to as phosphinic acid salts.

[Chemical Formula 5]

(Wherein R ¹ and R ² are hydrogen, an alkyl group having 1 to 6 carbon atoms and / or an aryl group, M is a metal, and m is a valence of M)

[Chemical Formula 6]

(Wherein R ³ and R ⁴ represent hydrogen, an alkyl group and / or an aryl group having 1 to 6 carbon atoms, R ⁵ represents an alkylene group having 1 to 6 carbon atoms or an arylene group, an alkylarylene group or an arylalkylene group having 6 to 10 carbon atoms , M is a metal, and n is a mantissa of M)

Such a phosphinic acid salt is a compound which is also referred to as a phosphinic acid metal salt. As R ¹ and R ² , hydrogen, a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, , And a phenyl group are exemplified. M is exemplified by aluminum, magnesium and calcium, and the number m is an integer of 2 to 4.

Specific examples thereof include calcium dimethylethylphosphinate, calcium methylethylphosphinate, calcium diethylphosphinate, calcium phenylphosphinate, calcium biphenylphosphinate, magnesium dimethylphosphinate, magnesium methylethylphosphinate, magnesium diethylphosphinate, phenyl Magnesium phosphinate, magnesium biphenylphosphinate, aluminum dimethylphosphinate, aluminum methylethylphosphinate, aluminum diethylphosphinate, aluminum phenylphosphinate, and aluminum biphenylphosphinate.

In the diphosphonic acid salt, R ³ and R ⁴ are exemplified by hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, pentyl, Examples of R ⁵ include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group and a phenylene group. M is exemplified by aluminum, magnesium and calcium, and the number n is an integer of 2 to 4.

Examples of the diphosphinic acid salt represented by the formula (2) include alkane bis (meth) acrylates such as calcium alkanephosphosphinic acid such as ethane-1,2-bis (phosphinic acid) calcium and ethane-1,2-bis (methylphosphinic acid) (Alkylphosphinic acid) calcium, magnesium alkanephosphosphinic acid, alkanebis (alkylphosphinic acid) magnesium, aluminum alkanebisphosphinate, and alkanebis (alkylphosphinic acid) aluminum.

Among these phosphinic acid salts, aluminum diethylphosphinate is particularly preferable.

The use of such phosphinic acid salts as the flame retardant component of the present invention is advantageous in that the effect of lowering the physical properties of a polyester having a high strength such as polyalkylene terephthalate or polyalkylene naphthalate is smaller than that of a conventional phosphorus flame retardant , A large amount of a flame retardant component can be added to the extent that it can not be added until now. Therefore, when the film is processed into a laminated use with a metal layer, for example, it has the same high flame retardancy as that of the flame-retardant polyester film itself.

Further, the flame-retardant biaxially oriented polyester film of the present invention contains such phosphinic acid salts and is biaxially stretched to exhibit high reflectance characteristics.

The content of these phosphinic acid salts is 2 wt% or more and 40 wt% or less based on the weight of the flame retardant base layer. The lower limit of the content of these phosphinic acid salts is preferably 4% by weight, more preferably 6% by weight, still more preferably 10% by weight, particularly preferably 15% by weight. The upper limit of the content of the phosphinic acid salt is preferably 35% by weight, more preferably 30% by weight, still more preferably 25% by weight, particularly preferably 20% by weight. When the content of the phosphinic acid salts is less than the lower limit, the flame retardancy is insufficient. On the other hand, if the content of the phosphinic acid salts exceeds the upper limit, the film composition of the film is lowered.

The average particle diameter of these phosphinic acid salts is preferably 0.1 mu m or more and 35 mu m or less. If the average particle diameter is less than the lower limit, the handling property of the film during film production may be lowered. In addition, when the average particle diameter exceeds the upper limit, the film strength may be lowered or broken.

Also, since the phosphinic acid salts of the present invention have such an average particle size, voids are easily generated at the interface between the phosphinic acid salts and the polyester by biaxial stretching, and the reflectance of the obtained biaxially oriented polyester film tends to be high , A reflectance characteristic is also exhibited with a flame retarding effect. Also, as the average particle diameter is smaller, the reflectance tends to increase as described later.

(Phosphorus atom concentration)

The phosphorus atom concentration in the present invention is preferably 1 wt% or more and 8 wt% or less based on the weight of the flame retardant base layer. The lower limit of the phosphorus atom concentration is more preferably 1.5% by weight, still more preferably 2.0% by weight, particularly preferably 2.5% by weight, particularly preferably 3.0% by weight. On the other hand, the upper limit of the phosphorus atom concentration is more preferably 7.0% by weight, and still more preferably 6.5% by weight.

INDUSTRIAL APPLICABILITY The present invention is based on the finding that the use of the phosphinic acid salts of the present invention for polyesters having high strength such as polyalkylene terephthalate or polyalkylene naphthalate makes it possible to obtain a poly And is characterized in that it does not hinder the water-decomposability. Therefore, it is possible to add a large amount to these polyesters, and the phosphorus atom concentration in the flame-retarded substrate layer can be increased to such an extent that it can not be obtained by the conventional phosphorus component.

On the other hand, if it is attempted to raise the phosphorus atom concentration to more than the upper limit value, the amount of the phosphinic acid salt to be added is too much, and the film composition of the film becomes insufficient. Further, even in a range close to the lower limit value of the phosphorus atom concentration, that is, in a range close to the content of the conventional phosphorus component, the radical trapping effect by the metal component constituting the phosphinic acid salts results in a higher flame retardancy And the same flame retardancy as that of the flame-retardant polyester film itself is reproduced even when it is processed into a laminated use with a metal layer.

(Other additives)

In order to improve the handleability of the film, the flame-retardant biaxially oriented polyester film of the present invention may contain inert particles or the like in a range that does not impair the effects of the present invention. Examples of such inert particles include inorganic particles (for example, kaolin, alumina, titanium oxide, calcium carbonate, silicon dioxide, etc.) containing elements of Periodic Table of Elements IIA, IIB, IVA, , Cross-linked polystyrene, crosslinked acrylic resin particles, and the like.

When the inert particles are contained, the average particle size of the inert particles is preferably in the range of 0.001 to 5 mu m, more preferably in the range of 0.01 to 10 wt%, more preferably 0.05 to 10 wt% 5% by weight, particularly preferably 0.05 to 3% by weight.

If necessary, additives such as a heat stabilizer, an antioxidant, an ultraviolet absorber, a releasing agent, a coloring agent and an antistatic agent may be added to the flame-retardant biaxially oriented polyester film of the present invention within the range not hindering the object of the present invention .

(Layer thickness)

The thickness of the flame-retardant base layer in the present invention is preferably 2 mu m or more and 200 mu m or less. Conventionally, when the flame retardant is added to the polyester base layer by the method of adding a flame retardant agent, the mechanical properties of the base layer and the hydrolysis resistance deteriorate, so that the polyester base layer itself is flame retarded by the phosphorus flame retardant The present invention has a feature that a phosphorus-based flame retardant can be added to the polyester base layer itself having such a thickness, whereas a method of laminating other layers containing a flame retardant agent on the base layer has been taken.

The thickness of the flame retardant base layer can be adjusted in accordance with the use within the above-described range. For example, in the case of a flat cable application, it is more preferably 2 to 100 占 퐉, still more preferably 5 to 75 占 퐉, particularly preferably 10 to 50 占 퐉. It is more preferably 2 to 150 μm, more preferably 5 to 100 μm, particularly preferably 10 to 75 μm in the case of use for a flexible printed circuit board, more preferably 5 to 100 μm, More preferably 10 to 150 占 퐉, particularly preferably 20 to 100 占 퐉 in the case of the reflection plate application, more preferably 50 to 200 占 퐉, still more preferably 100 to 200 占 퐉, particularly preferably 150 to 200 占 퐉, 200 mu m.

[Heat seal layer]

The flame-retardant biaxially oriented polyester film of the present invention preferably has a heat-seal layer on at least one side of the flame-retarded substrate layer. The heat seal layer may be a layer coated with a heat-sealable adhesive, or may be a layer composed of a polymer having a melting point lower than that of the flame retardant base layer.

The heat-sealable adhesive may also be referred to as a hot-melt adhesive, and known adhesives may be used. For example, the product name "HM326" manufactured by CEMEDINE Co., Ltd., and "ERPAN PH" manufactured by Nippon Matay Co., Ltd.

As a layer composed of a polymer having a melting point lower than that of the flame retardant base layer, for example, a layer using a copolymer polyester is exemplified.

As a main component of such a co-polyester, a polyester of the kind described in the flame retardant base layer can be used. Of these, ethylene terephthalate or ethylene naphthalate is preferable. The main component amount of the co-polyester is preferably 50 mol% or more, and more preferably 60 mol% or more, based on the total repeating units of the polyester constituting the heat-seal layer.

It is also preferable that the incidental component constituting such a co-polyester is larger than the total copolymerization amount of the polyester in the flame retardant base layer and less than 50 mol% based on the total repeating units of the polyester in the heat seal layer. Since the melting point of the copolymer polyester is relatively lower than that of the polyester of the flame retardant base layer, it is preferable that such a copolymer polyester is used as a counter material to be bonded to the heat seal layer side of the flame retardant polyester film of the present invention, specifically, The heat sealing layer in a molten state can be thermally fused and adhered to the opposing member by performing hot press treatment at a temperature equal to or higher than the melting point of the heat seal layer and lower than the melting point of the flame retardant base layer.

As an additional component constituting such a copolymer polyester, isophthalic acid, terephthalic acid, 2,6-naphthalene dicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 2,7-naphthalene dicarboxylic acid, p- Dicarboxylic acid components such as benzoic acid and the like, and diol components such as trimethylene glycol, hexamethylene glycol, neopentyl glycol, ethylene oxide adduct of bisphenol sulfone, and the like can be preferably exemplified.

It is preferable that such a heat-seal layer is formed when it is used as a flat cable or a solar cell back sheet.

<Hydrolysis resistance>

The flame retardant biaxially oriented polyester film of the present invention preferably has a tensile strength retention ratio of 50% or more after being treated in a saturated steam at 121 占 폚 and 2 atmospheric pressure for 10 hours. The retention of the film tensile strength is more preferably 60% or more. Such a tensile strength retention ratio is referred to as a film continuous film production direction of the polyester film (hereinafter sometimes referred to as longitudinal direction, longitudinal direction, MD direction) or orthogonal direction (hereinafter referred to as width direction, And the tensile strength retention ratio in at least one direction of the tensile strength retention ratio is more preferably satisfied in both directions.

By using the phosphinic acid salts of the present invention as the flame retardant component of the flame-retardant biaxially oriented polyester film of the present invention, it is possible to maintain a high film tensile strength retention ratio even after the heat treatment because of excellent flame retardancy and excellent hydrolysis resistance.

&Lt; Reflectivity characteristics of film &

The flame-retardant biaxially oriented polyester film of the present invention has flame retardancy, excellent hydrolysis resistance and high reflectance characteristics at the same time. Specifically, the average reflectance of the polyester film at a wavelength of 400 to 700 nm is preferably 70% or more and 100% or less, more preferably 75% or more and 100% or less, more preferably 80% or more and 100% or less desirable. By having such a reflectance characteristic, it can be preferably used as a reflector having, for example, flame retardance and reflection characteristics.

Such reflectance characteristics are obtained by a method of laminating layers containing a flame retardant by using white particles for enhancing the reflectance on the substrate or a matrix resin and an emulsion resin for a conventional flame retardant reflection plate, , The voids can be efficiently formed by adding the phosphinic acid salts of the present invention to the substrate layer and biaxially stretching to improve the reflectance while obtaining the flame retardancy.

Among the phosphinic acid salts of the present invention, the reflectance characteristics can be further improved by using a phosphor having an average particle diameter of 1 탆 or more and 10 탆 or less, more preferably 1 탆 or more and 5 탆 or less.

<Film density>

The flame-retardant biaxially oriented polyester film of the present invention also has a feature that the film density is smaller than that of a general polyester film.

Specifically, the film density is preferably 0.7 g / cm ³ or more and 1.3 g / cm ³ or less, more preferably 0.8 g / cm ³ or more and 1.2 g / cm ³ or less, particularly preferably 0.8 g / cm ³ or more 1.1 g / cm ³ or less. Such a film density is obtained by generating a void at the interface between phosphinic acid salts and polyester by using a specific amount of phosphinic acid salts having the average particle size described above and biaxially stretching the polyester film.

By having such a film density, it is possible to obtain a flame-retardant biaxially oriented polyester film excellent in bending property and peelability of the film even in a state containing a large amount of phosphinic acid salts, It is easy to perform punching in the form of various applications of the present invention. On the other hand, the density decreases as the content of phosphinic acid salts increases, but when the bending property is required, the lower limit of the density is preferably 0.8 g / cm ³ .

The flame-retardant biaxially oriented polyester film of the present invention is preferably used for a flexible printed circuit, a flat cable and the like requiring flexibility because it has flame retardancy and hydrolysis resistance as well as excellent bending properties.

&Lt; Surface roughness of base layer >

The surface roughness Ra of the flame-retarded substrate layer of the present invention is preferably 0.1 mu m or more and 2 mu m or less, more preferably 0.2 mu m or more and 1.5 mu m or less, and still more preferably 0.5 mu m or more and 1.5 mu m or less. Such surface roughness is obtained by using a specific amount of phosphinic acid salts having the above-mentioned average particle size in the base layer.

Since the flame retardant base layer is such a rough surface, the adhesion when laminated with other layers through a heat-seal layer, an adhesive layer, or the like is improved and can be suitably used for applications such as flat cables and solar cell back sheets have.

<Film Manufacturing Method>

As a method for producing the flame-retardant biaxially oriented polyester film of the present invention, there can be enumerated a film production method in which a sheet constituting the substrate layer is melt-extruded and solidified and the sheet is stretched in two directions.

The film can be produced by a known film production method, for example, by sufficiently drying a polyester containing a phosphinic acid salt, and then melt- ing in an extruder at a temperature from the melting point to (melting point +70) , Melt-extruded through a T-die, and the film-like melt is rapidly quenched on a cooling roll (casting drum) to form an unstretched film, followed by continuous or simultaneous biaxial stretching to heat-fix have. When the film is produced by sequential biaxial stretching, the unstretched film is stretched in the longitudinal direction at a temperature of 60 to 170 DEG C in the range of 2.3 to 5.5 times, more preferably in the range of 2.5 to 5.0 times, Stretching is carried out at 80 to 170 DEG C in the range of 2.3 to 5.0 times, more preferably 2.5 to 4.8 times.

The heat setting is preferably heat-set at 180 to 260 ° C, more preferably 190 to 240 ° C under tension or limited shrinkage, and the heat setting time is preferably 1 to 1000 seconds. In case of simultaneous biaxial stretching, the above stretching temperature, stretching ratio, heat fixing temperature and the like can be applied. Also, relaxation treatment may be performed after the heat is fixed.

When a layer composed of a polymer having a melting point lower than that of the flame retardant base layer is formed as the heat seal layer, it is supplied to an extruder different from the flame retardant base layer and melted at a temperature ranging from the melting point to (melting point +70) For example, a method in which a laminated unstretched film is obtained by a simultaneous lamination extrusion method using a multi-manifold die. As the subsequent stretching method, the above-described method can be used.

When a heat-sealable adhesive layer is formed as a heat-seal layer, a method of applying an adhesive on the obtained base layer can be mentioned.

&Lt; Flame retardant biaxially oriented polyester film laminate >

The flame-retardant biaxially oriented polyester film of the present invention can be used as a flame-retardant biaxially oriented polyester film laminate laminated with a metal layer. Here, the metal layer includes a layer formed in a film on a film, a wire or the like, a circuit having a constant pattern or the like, and the like.

When the flame-retardant biaxially oriented polyester film is laminated with the metal layer, it is preferable to laminate the laminate on the heat-seal layer of the flame-retardant biaxially oriented polyester film. By stacking the metal layer with the heat-seal layer interposed therebetween, a flame-retardant biaxially oriented polyester film laminate can be obtained by a simple method.

Such a flame retardant biaxially oriented polyester film laminate can be suitably used for applications requiring flame retardancy or hydrolysis resistance, and examples thereof include applications such as flat cables and flexible printed circuit boards. In addition, it can be used in applications other than those in which the metal layer is bonded to the metal layer.

(Flat cable)

The flame-retardant biaxially oriented polyester film of the present invention and the laminate thereof can be used as a covering material for a flat cable. The flat cable is a flat cable in which a conductive metal layer is sandwiched with an electrically insulating covering material.

In the case of producing a flat cable using the flame-retardant biaxially oriented polyester film of the present invention, two flame retardant biaxially oriented polyester films having a heat seal layer are used to face the heat seal layers, and a plurality of Flame retardant flat cables can be manufactured by arranging wires in parallel at intervals and then pressing the heat seal layer in a molten state in a temperature range not lower than the melting point of the heat seal layer and lower than the melting point of the flame retardant base layer, have.

As the wire, a conventional wire used for a flat cable can be used, and examples thereof include copper, plated copper, silver and the like. The conductors are thin or flat, and are arranged in parallel with a predetermined spacing.

The flat cable obtained by using the flame retardant biaxially oriented polyester film laminate of the present invention is excellent in the flame retardancy of the base material itself and is excellent in the flame retardancy of the biaxially oriented polyester film itself And also has sufficient resistance to hydrolysis, it is also excellent in long-term durability as a flat cable. Further, since the flame-retardant biaxially oriented polyester film of the present invention can satisfy flame retardancy and bending properties, a flame-retardant flat cable having high flexibility can be obtained.

Further, the flame-retardant biaxially oriented polyester film of the present invention has a rough surface, and also has an effect of enhancing adhesion with an adhesive layer such as a heat seal layer.

(Flexible printed circuit board)

The flame-retardant biaxially oriented polyester film of the present invention and the laminate thereof can be used in a flexible printed circuit board.

When it is used for such a use, it is preferable that a metal layer is laminated on one surface of the flame-retardant biaxially oriented polyester film and used as a flexible printed circuit board. As the metal layer used in the present application, a copper foil can be exemplified. The means for bonding the metal layer and the concrete means of the shape are not particularly limited. For example, the metal layer may be laminated on a flame-retardant biaxially oriented polyester film, and then the metal layer may be pattern-etched. An additive method in which a metal is patterned on a film on a film, a stamping foil in which a metal layer pattered in a pattern is stuck to a flame-retardant biaxially oriented polyester film, or the like can be used.

The flexible printed circuit board obtained by using the flame retardant biaxially oriented polyester film laminate of the present invention has a very high flame retardancy of the substrate layer itself and is excellent in flame retardance biaxial orientation even when processed for use in a flexible printed circuit board laminated with a metal layer The long-time durability as a flexible printed circuit board is also excellent in that the same high flame retardancy as that of the polyester film itself is exhibited and also sufficient hydrolysis resistance is provided. Since the flame-retardant biaxially oriented polyester film of the present invention is also excellent in bending property, it is excellent in sticking property when processed into a flexible printed circuit board, and both flame retardancy and bending property can be satisfied. Therefore, A flexible printed circuit board is obtained.

The flame-retardant biaxially oriented polyester film and laminate thereof of the present invention have excellent reflectance characteristics and can be used as flexible printed circuit boards for LEDs.

(Solar cell)

The flame-retardant biaxially oriented polyester film of the present invention can be used for a back sheet of a solar cell.

The solar cell back sheet obtained using the flame-retardant biaxially oriented polyester film of the present invention can improve the long-term durability of the solar cell in that it has excellent flame retardancy and also has sufficient hydrolysis resistance.

Also, by containing the phosphinic acid salts of the present invention in the film, a high degree of whiteness is obtained, and the white sheet can be used as a back sheet of a solar cell requiring whiteness.

Further, the flame-retardant biaxially oriented polyester film of the present invention has a coarse surface, improves adhesion with EVA used as a filler for solar cells, and can further enhance long-term durability as a solar cell.

(Reflector)

The flame-retardant biaxially oriented polyester film of the present invention can have both flame retardance and hydrolysis resistance, and can be used as various reflectors because of having high reflectance characteristics. Specifically, a reflector of a liquid crystal display device, a reflector of a lighting device, and the like can be given.

In addition, when used as a reflector for a liquid crystal display device, the surface roughness characteristics of the present invention reduce the sticking to adjacent members, thereby suppressing deterioration of the reflectance characteristics during long-term use.

Example

Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited to these examples. In addition, each characteristic value was measured by the following method. In the examples, "parts" and "%" refer to parts by weight and% by weight unless otherwise specified.

(1) Type and content of polyester component

¹ H-NMR measurement, and ¹³ C-NMR measurement, the components and the copolymerization components of the polyester and the respective component amounts were specified.

(2) Types of phosphorus component

NMR and EPMA were used to specify the type of phosphorus component.

(3) phosphorus atom concentration

The phosphorus atom concentration was calculated from the light emission intensity of fluorescent X-rays for the flame retardant base layer.

(4) Thickness of each layer

The thickness of each layer of the laminated film was measured by using a Microtome 2050 manufactured by Reichert-Jung Co., Ltd., in which a small piece of the film was embedded in an epoxy resin (trade name "Epomount", manufactured by Refine Technology Co., Ltd.) And the thickness was measured at an acceleration voltage of 100 kV by a transmission electron microscope (LEM-2000).

(5)

A sample piece of a short strip cut into a 150 mm long × 10 mm wide film is hanged with a stainless steel clip in an environmental testing machine set at 121 ° C. 2 atm wet saturated mode and 100% RH. Thereafter, after 10 hours have elapsed, the sample piece is removed from the environmental tester and the tensile strength is measured. The measurement was performed five times, and the average value was obtained. The hydrolysis resistance was evaluated according to the following criteria. Tensilon UCT-100 type manufactured by Orientech was used as a measuring device.

Tensile strength retention ratio (%) = (tensile strength after treatment X / initial tensile strength X ₀ ) x 100

(Wherein, X tensile strength is 121 ℃, 2 atm, the tensile strength, the tensile strength X ₀ after a predetermined time from the processing conditions of 100% RH represents an initial tensile strength before treatment, respectively)

?: Tensile strength retention after 10 hours was at least 50%

X: tensile strength retention after 10 hours was less than 50%

(6) Flammability

The film samples were evaluated according to the UL-94 VTM method. The sample was cut into 20 cm x 5 cm and left for 48 hours at 23 2 deg. C and 50 5% RH. Thereafter, the lower end of the sample was separated from the burner by 10 mm and held vertically. The lower end of the sample was used as a heating source of a Bunsen burner having an inner diameter of 9.5 mm and a flame length of 19 mm for 3 seconds so as to contact the flame. The flame retardancy was evaluated according to the evaluation criteria of VTM-0, VTM-1 and VTM-2, and the largest number of ranks in the same rank among the measurement times of n = 5 was determined.

(7) Flammability of flat cable

A hot-melt adhesive (manufactured by Nihon Matai Co., Ltd., product name &quot; Erpani PH &quot;) was applied to one side of the film to a thickness of about 30 탆. A 35 탆 thick copper foil Two sheets of the films were stacked so that the heat seal layers faced each other with the copper foil therebetween, and were thermally fused to produce a flat cable sample.

For the film having the heat-seal layer made of the copolymer polyester layer, the heat-seal layer was opposed thereto and copper foils having a thickness of 35 탆 cut to a width of 3 mm between the films were arranged side by side and heat-sealed.

The temperature was 140 占 폚, the pressure was 2.8 kgf / cm2, and the heat fusion time was 2 sec in any heat fusion condition.

The fabricated flat cable samples were evaluated according to the UL-94V method. The sample was cut into 13 mm 125 mm and left for 48 hours at 50 5% RH. Thereafter, the lower end of the sample was separated 10 mm above the burner and held vertically. The lower end of the sample was used as a heating source of a Bunsen burner having an inner diameter of 9.5 mm and a flame length of 19 mm for 10 seconds to contact the flame. Self-extinguishing properties after isolation from flame were evaluated.

○: Digestion within 10 seconds after isolation from flame

×: burned for 10 seconds after isolating from flame

(8) Average particle diameter

The cross section of the flame retardant base layer was measured at 3500 times with respect to 20 particles by using Digital Microscope KH-3000 manufactured by Hirox Co., Ltd., and the average particle size was determined from the average value.

(9) Reflectance

The reflectance of the film-flame retardant layer surface when the integrating sphere was mounted on a spectrophotometer (UV-3101 PC manufactured by Shimadzu Corporation) and the BaSO ₄ white sheet was 100% was measured over 400 to 700 nm, The average reflectance at 탆 was obtained. The reflectance characteristics were evaluated according to the following criteria.

○: 75% or more and 100% or less

?: 70% or more and less than 75%

×: less than 70%

(10) Film density

The film was cut into 10 cm x 10 cm and the thickness of arbitrary 10 points was measured with an electric micrometer (ANRITS K-402B), and the average value was taken as the thickness of the film. Then, the film weight was measured to calculate the density Respectively.

(11) Surface roughness Ra of the flame-retardant base layer Ra

Using the SURFCORDER SE-30C manufactured by Kosaka Institute Co., Ltd., the surface roughness Ra of the flame retardant base layer was measured under the following conditions, and the calculated center line average roughness Ra was obtained. And evaluated according to the following evaluation criteria.

<Measurement Conditions>

Measurement length: 2.5 mm

Cutoff: 0.25 mm

Measurement environment: room temperature, atmospheric

<Evaluation Criteria>

?: 0.2 占 퐉 or more and 2 占 퐉 or less

?: 0.1 占 퐉 or more and less than 0.2 占 퐉

X: less than 0.1 占 퐉

(12) My thief

The number of bending times until the film sample was broken at a bent radius of curvature of 0.38 mm, a load of 10 N, and a bending speed of 175 cpm was measured according to JIS C5016 using an aberrant tester in MIT and evaluated according to the following criteria .

○: 2000 times or more

DELTA: 500 times or more and less than 2000 times

×: less than 500 times

[Example 1]

(Polyester transesterification catalyst: manganese acetate manganese acetate, polymerization catalyst: antimony trioxide) having an intrinsic viscosity of 0.60 dl / g and a terminal carboxyl group concentration of 25 equivalents / ton was used as the polyester and aluminum dimethylphosphinate Phosphorus compound A, average particle diameter: 2 占 퐉) was contained in an amount of 15% by weight based on the weight of the flame retardant base layer. The composition was dried in a dryer at 170 占 폚 for 3 hours and then put in an extruder. Extruded from a die slit at 280 DEG C, and then cooled and solidified on a casting drum set at a surface temperature of 25 DEG C to prepare an unstretched film.

This unoriented film was introduced into a roll group heated to 100 캜, stretched 3.5 times in the longitudinal direction (longitudinal direction), and cooled in a roll group of 25 캜. Subsequently, both ends of the longitudinally stretched film were introduced into a tenter while being held by a clip, and stretched 3.8 times in a direction perpendicular to the longitudinal direction (transverse direction) in an atmosphere heated at 120 캜. Thereafter, the film was thermally fixed at 230 DEG C in a tenter, relaxed by 2% in the transverse direction at 180 DEG C, uniformly squeezed and cooled to room temperature to obtain a biaxially oriented film of 50 mu m in thickness. Table 1 shows the properties of the obtained film. The film of this example was excellent in flame retardancy and hydrolysis resistance. The film of this example was also excellent in reflectance and bending properties.

Also, the flame retardancy was excellent even in the state of a flat cable manufactured with a copper foil sandwiched therebetween. The peel strength was measured for adhesion between the flame retardant base layer and the heat seal layer using the produced flat cable, and as a result, the strength was improved as compared with Comparative Example 1.

[Example 2]

A biaxially oriented film having a thickness of 50 占 퐉 was obtained in the same manner as in Example 1 except that the flame retardant was changed to aluminum diethylphosphinate (described as phosphorus compound B in Table 1, average particle diameter 2 占 퐉). Table 1 shows the properties of the obtained film. The film of this example was excellent in flame retardance, hydrolysis resistance, reflectance characteristics, and bending properties. Also, the flame retardancy was excellent even in the state of a flat cable manufactured with a copper foil sandwiched therebetween. The peel strength was measured for adhesion between the flame retardant base layer and the heat seal layer using the produced flat cable, and as a result, the strength was improved as compared with Comparative Example 1.

[Example 3]

A biaxially oriented film having a thickness of 50 탆 was obtained in the same manner as in Example 2 except that the content of the flame retardant was changed to 5% by weight. Table 1 shows the properties of the obtained film. The film of this example was excellent in flame retardancy, hydrolysis resistance and bending properties. Also, the flame retardancy was excellent even in the state of a flat cable manufactured with a copper foil sandwiched therebetween.

[Example 4]

A biaxially oriented film having a thickness of 50 탆 was obtained in the same manner as in Example 2 except that the content of the flame retardant was changed to 30% by weight. Table 1 shows the properties of the obtained film. The film of this example was excellent in flame retardance, hydrolysis resistance and reflectance characteristics. Also, the flame retardancy was excellent even in the state of a flat cable manufactured with a copper foil sandwiched therebetween.

[Example 5]

A biaxially oriented film having a thickness of 50 占 퐉 was obtained in the same manner as in Example 1 except that the flame retardant was changed to aluminum ethyl methylphosphinate (described as phosphorus compound C in Table 1, average particle diameter: 3 占 퐉). Table 1 shows the properties of the obtained film. The film of this example was excellent in flame retardance, hydrolysis resistance, reflectance characteristics, and bending properties. Also, the flame retardancy was excellent even in the state of a flat cable manufactured with a copper foil sandwiched therebetween.

[Example 6]

The procedure of Example 1 was repeated except that the flame retardant was changed to aluminum biphenylphosphinate (described as phosphorus compound D in Table 1, average particle size: 3 占 퐉) and the content was changed to 20% by weight based on the weight of the flame- Was carried out to obtain a biaxially oriented film having a thickness of 50 mu m. Table 1 shows the properties of the obtained film. The film of this example was excellent in flame retardance, hydrolysis resistance and reflectance characteristics. Also, the flame retardancy was excellent even in the state of a flat cable manufactured with a copper foil sandwiched therebetween.

[Example 7]

A biaxially oriented film having a thickness of 50 占 퐉 was obtained in the same manner as in Example 1 except that the flame retardant was changed to calcium dimethylphosphinate (described as phosphorus compound E in Table 1, average particle size: 5 占 퐉). Table 1 shows the properties of the obtained film. The film of this example was excellent in flame retardance, hydrolysis resistance, reflectance characteristics, and bending properties. Also, the flame retardancy was excellent even in the state of a flat cable manufactured with a copper foil sandwiched therebetween.

[Example 8]

A biaxially oriented film having a thickness of 50 占 퐉 was obtained in the same manner as in Example 1 except that the flame retardant was changed to calcium diethylphosphinate (described as phosphorus compound F in Table 1, average particle diameter: 5 占 퐉). Table 1 shows the properties of the obtained film. The film of this example was excellent in flame retardance, hydrolysis resistance, reflectance characteristics, and bending properties. Also, the flame retardancy was excellent even in the state of a flat cable manufactured with a copper foil sandwiched therebetween.

[Example 9]

Polyester-2,6-naphthalenedicarboxylate (transesterification catalyst: manganese acetate 4-hydrate, polymerization catalyst: antimony trioxide) having an intrinsic viscosity of 0.57 dl / g and a terminal carboxyl group concentration of 25 equivalents / ton was used as the polyester, The composition containing 15% by weight of aluminum phosphosilicate (phosphorus compound B) based on the weight of the flame retardant substrate layer was dried for 5 hours at 180 ° C in a dryer, and then put into an extruder to melt and knead at 300 ° C. Deg.] C, and then cooled and solidified on a casting drum set at a surface temperature of 60 DEG C to prepare an unstretched film.

The unoriented film was introduced into a roll group heated to 140 ° C, stretched 3.5 times in the longitudinal direction (longitudinal direction), and cooled in a roll group of 60 ° C. Subsequently, both ends of the longitudinally stretched film were introduced into a tenter while being held by a clip, and stretched 3.5 times in a direction perpendicular to the longitudinal direction (transverse direction) in an atmosphere heated at 150 캜. Thereafter, the film was thermally fixed at 230 DEG C in a tenter, relaxed by 2% in the transverse direction at 180 DEG C, uniformly squeezed and cooled to room temperature to obtain a biaxially oriented film of 50 mu m in thickness. Table 1 shows the properties of the obtained film. The film of this example was excellent in flame retardance, hydrolysis resistance, reflectance characteristics, and bending properties. Also, the flame retardancy was excellent even in the state of a flat cable manufactured with a copper foil sandwiched therebetween.

[Example 10]

A biaxially oriented film having a thickness of 50 탆 was obtained in the same manner as in Example 9 except that the content of the flame retardant was changed to 5% by weight. Table 1 shows the properties of the obtained film. The film of this example was excellent in flame retardancy, hydrolysis resistance and bending properties. Also, the flame retardancy was excellent even in the state of a flat cable manufactured with a copper foil sandwiched therebetween.

[Example 11]

The composition containing 20% by weight of diethylphosphinic acid aluminum (phosphorus compound B) based on the weight of the flame retardant base layer and the polyethylene terephthalate as a polyester was dried at 170 ° C for 3 hours and then put in an extruder And melt-kneaded at a melting temperature of 280 占 폚.

On the other hand, isophthalic acid copolymerized polyethylene terephthalate having an intrinsic viscosity of 0.59 dl / g obtained by copolymerizing isophthalic acid in an amount of 18 mol% based on the total repeating units of polyester in the heat seal layer was dried for 3 hours at 170 ° C for the heat seal layer And the mixture was put into the other extruder and melted at a melting temperature of 270 ° C.

(Thickness ratio of the flame retardant base layer: heat seal layer = 4: 1), and extruded from the die slit while maintaining the laminated structure. Thereafter, a casting drum To form an unstretched film consisting of two layers. The unoriented film was biaxially stretched in the same manner as in Example 1 to obtain a biaxially oriented film having a thickness of 50 占 퐉 (a flame retardant base layer: 40 占 퐉, heat seal layer: 10 占 퐉). Table 1 shows the properties of the obtained film. The film of this example was excellent in flame retardance, hydrolysis resistance and reflectance characteristics.

Also, the flame retardancy was excellent even in the state of a flat cable manufactured with a copper foil sandwiched therebetween.

[Examples 12 to 14]

A biaxially oriented film having a thickness of 50 占 퐉 was obtained by carrying out the same operation as in Example 2 except that aluminum diethylphosphinate (represented by phosphorus compound B in Table 1) was changed to an average particle diameter shown in Table 2 . Table 2 shows the properties of the obtained film. The film of this example was excellent in flame retardancy, hydrolysis resistance and bending properties. As for the reflectance characteristics, a higher reflectance was obtained as the average particle diameter of the flame retardant was smaller.

Also, the flame retardancy was excellent even in the state of a flat cable manufactured with a copper foil sandwiched therebetween.

[Comparative Example 1]

A biaxially oriented film having a thickness of 50 占 퐉 was obtained in the same manner as in Example 1 except that no flame retardant was added. Table 1 shows the properties of the obtained film. The film of this Comparative Example was excellent in the hydrolysis resistance, but the flame retardancy was not sufficient in both the film and the flat cable. The reflectance was also low.

[Comparative Example 2]

A biaxially oriented film having a thickness of 50 탆 was obtained in the same manner as in Example 2 except that the content of the flame retardant was changed to 45% by weight. Table 1 shows the properties of the obtained film. In this comparative example, the membrane composition was not sufficient and a biaxial oriented film could not be obtained.

[Comparative Example 3]

100 parts by weight of terephthalic acid dimethyl ester, 60 parts by weight of ethylene glycol, and 0.03 part by weight of manganese acetate manganate 4 as an ester exchange catalyst were subjected to ester exchange reaction according to a conventional method and then dispersed in ethylene glycol to prepare calcium carbonate 0.4% by weight (based on the weight of the film) of the particles was added. Subsequently, 10 parts by weight of 2-carboxyethyl methylphosphinic acid 2-hydroxyethyl (described as phosphorus compound G in Table 1) was added, and 0.03 part by weight of antimony trioxide was added. Subsequently, polycondensation was conducted under high temperature and high vacuum, To obtain a polyester having an intrinsic viscosity of 0.70 dl / g. The polyester thus obtained was dried in a dryer at 170 ° C for 3 hours and then put in an extruder. The polyester was melted at 260 ° C and extruded from a die slit, and then cooled and solidified on a casting drum set at a surface temperature of 25 ° C to form an unstretched film.

This unoriented film was stretched 3.5 times in the longitudinal direction (continuous film production direction) at 100 DEG C, then biaxially stretched at 130 DEG C in the transverse direction (width direction) at a rate of 3.8 times, , Relaxed 2% in the transverse direction at 200 ° C, uniformly thawed, and cooled to room temperature to obtain a biaxially oriented film having a thickness of 50 μm. Table 1 shows the properties of the obtained film. The film of this comparative example was excellent in the flame retardancy in the film, but the flame retardancy in the flat cable state was not sufficient. Further, the hydrolysis resistance and the reflectance were lowered as compared with the examples.

In Table 1 and Table 2, PET represents polyethylene terephthalate and PEN represents polyethylene-2,6-naphthalene dicarboxylate.

Industrial availability

The flame-retardant biaxially oriented polyester film of the present invention has a high flame retardancy without deteriorating the hydrolysis resistance of polyesters such as polyalkylene terephthalate or polyalkylene naphthalate and can be used as a flexible printed circuit board, Cable, solar cell back sheet or reflector.

Claims (8)

A flame retardant biaxially oriented polyester film comprising a flame retardant substrate layer, wherein the flame retardant substrate layer comprises polyethylene terephthalate or polyethylene naphthalate in an amount of more than 94% by weight and not more than 98% by weight based on the weight of the layer, A cosmetic composition comprising a phosphinic acid salt represented by the formula (1) or a diphosphinic acid salt represented by the formula (2) in an amount of 2% by weight or more and less than 6% by weight and an average particle diameter of the phosphinic acid salt or diphosphonic acid salt thereof is 1 탆 or more Mu m or less and an average reflectance of the polyester film at a wavelength of 400 to 700 nm is 70% or more and less than 75%
[Chemical Formula 1]

(Wherein R ¹ and R ² are hydrogen, an alkyl group having 1 to 6 carbon atoms and / or an aryl group, M is a metal, and m is a valence of M)
(2)

(Wherein R ³ and R ⁴ represent hydrogen, an alkyl group and / or an aryl group having 1 to 6 carbon atoms, R ⁵ represents an alkylene group having 1 to 6 carbon atoms or an arylene group, an alkylarylene group or an arylalkylene group having 6 to 10 carbon atoms , M is a metal, and n is a mantissa of M)
Flame retardant biaxially oriented polyester film laminate having a flame retardant biaxially oriented polyester film and a metal layer laminated thereon. The method according to claim 1,
Wherein the flame retardant base layer has a thickness of 2 占 퐉 or more and 200 占 퐉 or less. The method according to claim 1,
A polyester film obtained by treating the polyester film at 121 占 폚 in a saturated water vapor at 2 atmospheres for 10 hours, and a tensile strength retention ratio of 50% or more. The method according to claim 1,
Wherein the film density is not less than 0.7 g / cm &lt; ³ &gt; and not more than 1.3 g / cm &lt; ³ &gt; The method according to claim 1,
And the surface roughness Ra of the flame-retardant base layer is 0.1 占 퐉 or more and 2 占 퐉 or less. The method according to claim 1,
A flame retardant biaxially oriented polyester film laminate used as a flexible printed circuit or a flat cable. The method according to claim 1,
A flame-retardant biaxially oriented polyester film laminate having a heat-seal layer on at least one side of a flame retardant base layer. A flame retardant flat cable using the flame retardant biaxially oriented polyester film laminate according to any one of claims 1 to 7.