JPH07173430A - Coating composition and production of polyester film coated therewith for metal laminate - Google Patents

Abstract

PURPOSE:To obtain a coating compsn. effective as an adhesive layer between a polyester film and a metal sheet and useful for producing a metal-polyester laminate excellent in impact resistance by compounding a specific polycarbonate resin (compsn.) with a specific org. solvent in a specified wt. ratio. CONSTITUTION:This compsn. comprises 1-30 pts.wt. polycarbonate resin (compsn.) and 100 pts.wt. org. solvent nonreactive with the resin (compsn.) and boiling at 30-150 deg.C under normal pressure. The resin (compsn.) comprises 60-100wt.% polycarbonate which consists of repeating units of the formula (wherein Rl and R2 are each H, 1-5C alkyl, or 5-6C cycloalkyl provided they may combine with each other: R3 and R4 are each 1-5C alkyl, halogen, or phenyl; and m and n are each 0-2) and has a terminal-OH content of 20 equivalents/10<6>g or higher and a viscosity-average mol.wt. of 10,000-40,000 and 0-40wt.% polyester which is obtd. from an acid component contg. at least 70mol% terephthalic acid and/or isophthalic acid and a diol component contg. at least 70mol% ethylene glycol and/or tetramethylene glycol.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to coating compositions. More specifically, a coating composition obtained by dissolving a specific polycarbonate or a polycarbonate / polyester blend polymer having excellent adhesion to a metal in an organic solvent, and a metal obtained by coating the coating composition on a specific polyester film The present invention relates to a method for producing a polyester film for metal laminating, which is suitable for a laminated steel sheet having excellent adhesiveness and impact resistance.

[0002]

2. Description of the Related Art A metal container is generally coated to prevent corrosion on the inner and outer surfaces, but recently a thermoplastic resin film is used for the purpose of simplifying the process, saving energy, improving hygiene, and preventing pollution. Is being attempted. That is,
This is a method in which a thermoplastic resin film is laminated on a metal plate such as tin-free steel and then formed by drawing, ironing or the like. Polyolefin films and polyamide films have been tried as this thermoplastic resin film, but they do not satisfy all of the molding processability, heat resistance, aroma retention, and impact resistance.

On the other hand, a polyester film, especially a polyethylene terephthalate film, has attracted attention as having balanced properties, and several proposals based on this have been made. That is, (A) a biaxially oriented polyethylene terephthalate film is laminated on a metal plate via an adhesive layer of low melting point polyester and used as a can-making material (JP-A-56-1045).
No. 1, JP-A-1-192545). (B) Amorphous or extremely low crystalline aromatic polyester is laminated on a metal plate and used as a can-making material (JP-A-1-192545, JP-A-2-5733).
No. 9). (C) A low orientation, heat-set, biaxially stretched polyethylene terephthalate film is laminated on a metal plate and used as a can-making material (Japanese Patent Laid-Open No. 64-22530).

However, according to the studies made by the present inventors, none of them has sufficient characteristics, and each has the following problems.

Regarding (A), the biaxially oriented polyethylene terephthalate film is excellent in heat resistance and aroma retention,
Molding processability is insufficient, and whitening of the film (generation of microcracks) and breakage occur in the can manufacturing process with large deformation.

Regarding (B), since it is an amorphous or extremely low crystalline aromatic polyester, it has good moldability, but it is inferior in aroma retention, and printing after can making, retort sterilization treatment, etc. There is a problem that the post-treatment tends to cause embrittlement and the impact from the outside of the can causes cracking.

With respect to (C), it is difficult to produce a low-orientation film applicable to can manufacturing, and even if the film can be processed in a region having a low degree of deformation, subsequent printing,
The tendency that embrittlement is likely to occur due to post-treatment such as retort sterilization is the same as in (B) above.

In order to solve such a problem, the present inventors have considered variously using a film made of a copolyester and have made various studies. As a result, the copolyester film is excellent in molding processability, heat resistance, retort resistance, and aroma retention, but the impact resistance, particularly at a low temperature of 15 ° C. or lower, is insufficient. It has been found that when a metal can laminated with this film is dropped at a low temperature to give an impact, the film is likely to be cracked.

On the other hand, although polycarbonate is excellent in heat resistance, moldability and impact resistance, it usually has insufficient adhesiveness to metal, and even if it can be laminated on a steel sheet,
It was difficult to obtain a product that can withstand the subsequent can manufacturing process. The present inventors have studied the improvement of the adhesiveness of polycarbonate, and found that the adhesiveness is improved by increasing the amount of terminal OH groups of the polycarbonate.
This alone is still insufficient in aroma retention and can making processability,
It turns out that there is a need for further improvement.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to improve the impact resistance of a polyester film for metal laminating and to use a polycarbonate-based coating composition effective as an adhesive layer between a polyester film and a metal plate. It is intended to provide a method for producing a polyester film having excellent adhesiveness and impact resistance for a laminated steel sheet, which is obtained by coating the product and the composition.

[0011]

The object of the present invention comprises a repeating unit of the following formula (1), wherein the amount of terminal OH groups is 20:
Mol / 10 ⁶ g or more, viscosity average molecular weight of 10,000 to 4
60 to 100% by weight of the polycarbonate (A) of 0000, and 70 mol% or more of the acid component are terephthalic acid and / or
Or isophthalic acid, 70 mol% of the diol component
Polycarbonate resin or resin composition comprising 0 to 40% by weight of polyester (B), which is ethylene glycol and / or tetramethylene glycol, and a boiling point of 30 to 150 ° C. under normal pressure. And an organic solvent that is non-reactive with the organic solvent.
1 to 30 parts by weight of the resin or the coating composition containing the resin composition, and further polyethylene terephthalate or a copolymerized polyethylene terephthalate having a melting point of more than 200 ° C. to a film thickness of 5 to 75 μm with respect to parts by weight
This can be achieved by applying the above coating composition to a film to form a polycarbonate resin layer or a resin composition layer having a film thickness of 0.1 to 5 μm.

[0012]

[Chemical 3]

[In the formula (1), R ₁ and R ₂ are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms and a carbon atom having 5 carbon atoms.
Selected from the cycloalkyl groups of 6 to 6, R ₁ and R ₂ may be bonded to each other. R ₃ and R ₄ are each independently selected from an alkyl group having 1 to 5 carbon atoms, a halogen atom and a phenyl group, and m and n are each independently 0, 1 or 2. The polycarbonate used in the present invention is essentially composed of the repeating unit of the above formula (1).

In the formula (1), R ₁ and R ₂ are independently a hydrogen atom,
It is selected from an alkyl group having 1 to 5 carbon atoms and a cycloalkyl group having 5 to 6 carbon atoms, and examples thereof include methyl, ethyl, propyl, n-butyl, isobutyl, pentyl and cyclohexyl. R ₁ and R ₂ may be bonded to each other, in which case they form a cycloalkane ring.

Next, R ₃ and R ₄ are each independently selected from an alkyl group having 1 to 5 carbon atoms, a halogen atom and a phenyl group, for example, methyl, ethyl, propyl, normabutyl, isobutyl, pentyl, phenyl, chloro, Bromo etc. can be illustrated.

Further, m and n are independently 0, 1 or 2.

The polycarbonate composed of the repeating unit represented by the above formula (1) may be a copolymer containing two or more kinds of the above repeating units.

In the polycarbonate having the repeating unit of the formula (1), R ₁ and R ₂ are methyl groups, and n,
A bisphenol A type polycarbonate in which m is 0 is particularly preferable.

The polycarbonate of the present invention must have an amount of terminal OH groups of 20 mol / 10 ⁶ g or more. When the amount of terminal OH groups is less than 20 mol / 10 ⁶ g, sufficient adhesive force cannot be obtained when laminated on a metal plate.

The amount of terminal OH groups must be 20 eq / 10 ⁶ g or more, but from the viewpoint of further improving the adhesiveness, it is preferably 25 eq / 10 ⁶ g or more, and 3
More preferably 0 eq / 10 ⁶ g or more, 40
More preferably eq / 10 ⁶ g or more, 50
It is particularly preferable that the eq / 10 ⁶ g or more. In practice, the upper limit is preferably about 200 eq / 10 ⁶ g.

The polycarbonate used in the present invention preferably has a viscosity average molecular weight of 10,000 to 40,000. When the viscosity average molecular weight is less than 10,000, the mechanical properties of the polycarbonate itself become insufficient, the polycarbonate cannot withstand squeezing, ironing, etc. during molding, and peeling from the metal surface is likely to occur. When the viscosity average molecular weight is larger than 40,000, the polymer has a high melt viscosity and the wettability with the metal plate at the time of adhesion is insufficient, which is not preferable. The viscosity average molecular weight of the polycarbonate is preferably 15,000 to 40,000, more preferably 20,000 to 35,000.

Polycarbonate resins are generally prepared by reacting a corresponding dihydric phenol with a carbonate precursor such as phosgene in the presence of a known acid acceptor or molecular weight regulator in a solvent such as methylene chloride (interfacial polymerization method). ) Or a corresponding dihydric phenol and a carbonate precursor such as diphenyl carbonate by a transesterification reaction (melt polymerization method).

The method for producing the polycarbonate resin used in the present invention is not particularly limited, but it can be produced, for example, by the following method. That is, (a) a method in which a dihydric phenol is excessively reacted with a carbonate precursor when producing a resin by an interfacial polymerization method, (b) a method in which endcapping is performed when producing a resin by an interfacial polymerization method, (C)
When a resin is produced by a melt polymerization method, a ratio of a dihydric phenol to a carbonate precursor is adjusted, and (d) When a resin is produced by a melt polymerization method, a polyhydroxy compound is added in the latter stage of the polymerization reaction. Method, (e) Terminal OH amount 20e
A method of increasing the amount of terminal OH by reacting the polycarbonate resin with the dihydric phenols by melt-mixing a q / 10 ⁶ g-terminated polycarbonate resin and an appropriate amount of the dihydric phenols, and optionally adding a catalyst. Is adopted.

Next, the polyester (B) used in the present invention
Is a homo- or copolyester in which 70 mol% or more of the acid component is terephthalic acid and / or isophthalic acid and 70 mol% or more of the diol component is ethylene glycol and / or tetramethylene glycol.

The polyester has at least 70 acid components.
It is necessary that mol% is terephthalic acid and / or isophthalic acid, and among them, 80 mol% or more is preferably terephthalic acid and / or isophthalic acid,
It is particularly preferable that 90 mol% or more is terephthalic acid and / or isophthalic acid. The ratio of terephthalic acid and isophthalic acid is 0.5 in terms of the ratio of (the number of moles of terephthalic acid) / (the number of moles of terephthalic acid + the number of moles of isophthalic acid).
It is preferably not less than 0.6, more preferably not less than 0.6, particularly preferably not less than 0.7. Three
The acid component other than terephthalic acid and isophthalic acid which can be copolymerized at a ratio of less than 0 mol% is not particularly limited as long as it is a divalent carboxylic acid, and examples thereof include 2,6-naphthalenedicarboxylic acid and 4,4 ′. -Biphenyldicarboxylic acid, sebacic acid, adipic acid and the like can be preferably exemplified.

70% or more of the diol component is required to be ethylene glycol and / or tetramethylene glycol, but it is preferable that 80% or more is ethylene glycol and / or tetramethylene glycol, and 90% or more is ethylene. Particularly preferred is glycol and / or tetramethylene glycol. The ratio of ethylene glycol and tetramethylene glycol to be used is not particularly limited, and it is also preferable to use each alone. The diol component other than ethylene glycol and tetramethylene glycol that can be used as the copolymerization component is not particularly limited, but, for example, hexamethylene glycol, neopentyl glycol, diethylene glycol, cyclohexanedimethanol and the like can be preferably exemplified. These polyesters can be produced by a conventionally known melt polymerization method.

Preferred specific examples of the polyester (B) constituting the resin composition in the present invention include polyethylene terephthalate, polytetramethylene terephthalate, poly (ethylene terephthalate / tetramethylene terephthalate) copolymer, poly (ethylene terephthalate / ethylene). An isophthalate) copolymer etc. can be mentioned.

These polyesters may be used either individually or in combination of two or more.

The polyester (B) is phenol /
In 1,1,2,2-tetrachloroethane mixed solvent (weight ratio 60/40), the intrinsic viscosity measured at 35 ° C is 0.3 to
It is preferably 1.2, and particularly preferably 0.4 to 1.0.

The mixing ratio of the polycarbonate (A) and the polyester (B) in the polycarbonate resin or resin composition constituting the coating composition of the present invention is
Polycarbonate 60-100% by weight, polyester 0
-40% by weight. If the proportion of the polycarbonate is less than 60% by weight, the characteristic of the polycarbonate that the dent resistance is very good is lost.

The proportion of polycarbonate in the resin composition is preferably 60 to 99% by weight, and 70 to 99% by weight.
It is more preferably 98% by weight, and particularly preferably 80 to 97% by weight.

The resin composition constituting the coating composition of the present invention can be obtained by uniformly kneading the above components (A) and (B) under melting conditions. The melt-kneading conditions are not particularly limited as long as the two components can be closely dispersed or compatible with each other, but the melt temperature is preferably 240 to 330 ° C, more preferably about 260 to 310 ° C. The kneading time is preferably 2 to 60 minutes, more preferably 5 to 30 minutes. For the kneading, a batch type mixing container may be used, or a melt mixing extruder such as an extruder may be used. During this blending, the polycarbonate (A) and the polyester (B) may be partially copolymerized by a transesterification reaction, and on the contrary, the solubility in an organic solvent is improved, which may be preferable. .

The polyester (B) constituting the resin composition is preferably one produced by using a germanium compound and / or a titanium compound as a catalyst. Such polyester is excellent in film forming stability when forming a film after being melt-mixed with polycarbonate.

At the time of the above-mentioned melt-kneading, if necessary, a catalyst and / or various stabilizers may be added.

The coating composition of the present invention is prepared by adding the above polycarbonate resin or resin composition to an organic solvent which has a boiling point of 30 to 150 ° C. under normal pressure and is non-reactive with the resin or the resin composition. It can be obtained by dissolving.
The organic solvent used here may be one that satisfies the above conditions, and specifically, methylene chloride, chloroform, 1,2-dichloroethane, trichlene, tetrahydrofuran, dioxane, 1,3-dioxolane, methyl ethyl ketone, methyl. Examples thereof include isobutyl ketone, acetonitrile, ethyl acetate and dimethylformamide. These solvents may be used alone or in combination of two or more.

The proportion of the solvent and the polycarbonate resin or resin composition used is preferably 1 to 30 parts by weight, more preferably 2 to 20 parts by weight, based on 100 parts by weight of the solvent. Parts, particularly preferably 3 to 10 parts by weight.

In the coating composition of the present invention, when such a composition comprises the above polycarbonate and the above organic solvent which is non-reactive with the above polycarbonate, an epoxy group is added to the molecule in an amount of 2
It is preferable to use a polyepoxy compound containing one or more. Examples of the polyepoxy compound include the following compounds.

1) As a glycidyl ether compound, 2,2-bis (4-hydroxyphenyl) propane (bisphenol A), 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxy) Aromatic polyols such as phenyl) cyclohexane, 4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfone, resorcinol, phenol novolac, cresol novolac, naphthol novolac; phenol, naphthol Polyols obtained by dehydration condensation reaction of an aromatic hydroxy compound such as, for example, with an aldehyde such as glyoxal, glutaraldehyde, benzaldehyde, p-hydroxybenzaldehyde under an acidic catalyst; Examples thereof include glycidyl ethers such as polyols such as polyhydric alcohols such as butanediol, neopentyl glycol, glycerol, polyethylene glycol and polypropylene glycol.

2) Examples of glycidyl ester compounds include glycidyl esters of polycarboxylic acids such as phthalic acid, isophthalic acid, naphthalenedicarboxylic acid, trimellitic acid and the like.

3) A compound obtained by substituting the active hydrogen bonded to the nitrogen atom of a nitrogen-containing compound such as aniline, isocyanuric acid and 4,4'-diaminodiphenylmethane with a glycidyl group as the N-glycidyl compound.

4) Examples of glycidyl ether ester compounds include glycidyl ether esters of hydroxycarboxylic acids such as p-hydroxybenzoic acid and hydroxynaphthoic acid.

5) Epoxy resins obtained from unsaturated alicyclic compounds such as cyclopentadiene and dicyclopentadiene, triglycidyl compounds of p-aminophenol, vinylcyclohexenedioxide and the like can be exemplified.

These polyepoxy compounds may be used either individually or in combination of two or more. Among these, a diglycidyl ether of 2,2-bis (4-hydroxyphenyl) propane (bisphenol A) can be preferably used as the polyepoxy compound.

The polyepoxy compound has the function of improving the adhesion to metal without impairing the mechanical properties and heat resistance inherent in polycarbonate. When the polyepoxy compound is used, the proportion used is 0.1 to 10% by weight based on the polycarbonate. The use ratio is preferably 0.2 to 7% by weight with respect to the polycarbonate, and more preferably 0.3 to 5% by weight with respect to the polycarbonate.

The coating composition of the present invention contains as a component a polycarbonate or a resin composition of polycarbonate and polyester which has excellent adhesion to a polyester film and a metal plate. It can be effectively used as a layer. As a specific application method, the coating composition of the present invention is applied to a polyester film, and the polyester film having a polycarbonate coating layer or a resin composition coating layer obtained by heating to remove the solvent is laminated on a metal plate. And a method of applying the coating composition of the present invention to a metal plate and laminating a polyester film on the metal plate having the obtained polycarbonate coating layer or resin composition coating layer.

Next, the former application method, that is, the method for producing a polyester film for metal laminating, in which the coating composition of the present invention is applied, will be described. The polyester film that is the base of the metal laminating film is polyethylene terephthalate or has a melting point (Tm)
Above 200 ° C, preferably glass transition temperature (Tg) 6
It is a copolymerized polyethylene terephthalate at 0 ° C or higher.

The copolymerization component (third component) in the latter copolymerized polyethylene terephthalate may be an acid component or an alcohol component. Isophthalic acid as the acid component,
Examples thereof include aromatic dicarboxylic acids such as phthalic acid and naphthalene dicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid and decanedicarboxylic acid, and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid. Butanediol as the alcohol component,
Examples thereof include aliphatic diols such as neopentylene glycol and hexanediol, and alicyclic diols such as cyclohexanedimethanol. These may be used alone or in combination of two or more.

The proportion of the copolymerization component depends on the kind thereof, but as a result, the melting point of the polymer exceeds 200 ° C., preferably 210 ° C. or higher, more preferably 215 ° C. or higher. When the melting point is 200 ° C. or lower, the heat resistance is poor, which is not preferable.

The melting point (Tm) of the polyester is measured by Du Pont Instruments DS.
By using C, a melting peak is obtained at a temperature rising rate of 20 ° C./min. The sample amount is about 20 g.

The intrinsic viscosity of polyethylene terephthalate or copolymerized polyethylene terephthalate constituting the polyester film is not particularly limited, but phenol /
The value measured at 35 ° C. in a 1,1,2,2-tetrachloroethane mixed solvent (weight ratio 60/40) was 0.40 to 40.
It is preferably 0.80, especially 0.45
It is more preferably about 0.75, particularly 0.50.
˜0.70 is preferred.

Further, the copolymerized polyethylene terephthalate constituting the polyester film preferably has a glass transition temperature (Tg) of 60 ° C. or higher, more preferably 65 ° C. or higher. As such a copolymerized polyethylene terephthalate, an isophthalic acid copolymerized polyethylene terephthalate is particularly preferable because a copolymerized polyester having a high glass transition temperature can be obtained.

The above polyester is not limited by its manufacturing method. For example, in the case of copolymerized polyethylene terephthalate, a method of subjecting terephthalic acid, ethylene glycol and a copolymerization component to an esterification reaction and then subjecting the resulting reaction product to a polycondensation reaction to obtain a copolymerized polyester, or dimethyl terephthalate, ethylene A preferred method is a method in which a glycol and a copolymerization component are transesterified, and then a reaction product obtained is subjected to a polycondensation reaction.

If necessary, the above polyester may be used.
Other additives such as antioxidants, heat stabilizers, ultraviolet absorbers and antistatic agents can also be added. Further, the polyester constituting the polyester film layer usually has handleability (winding property) in the film manufacturing process.
In order to improve, it is preferable to contain 1% by weight or less of a lubricant. This lubricant may be inorganic or organic, but is preferably inorganic. Examples of the inorganic lubricant include silica, alumina, titanium dioxide, calcium carbonate, barium sulfate, etc., and examples of the organic lubricant include crosslinked polystyrene particles,
Examples thereof include silicone particles. In both cases, it is desirable that the average particle size is 2.5 μm or less. When the average particle size of the lubricant exceeds 2.5 μm, coarse lubricant particles (for example, 10 μm or more) in the portion deformed by processing such as deep drawing can manufacturing are used. (Particles of (1)) as a starting point to generate pinholes or break in some cases, which is not preferable.

In particular, a preferable lubricant in terms of pinhole resistance is a monodisperse lubricant having an average particle size of 2.5 μm or less and a particle size ratio (major axis / minor axis) of 1.0 to 1.2. It is a lubricant. Examples of such a lubricant include true spherical silica, true spherical titanium oxide, true spherical zirconium, true spherical silicone particles and the like.

The polyester film used in the present invention may be an unstretched film or a biaxially stretched and heat-set stretched film. Of these, a biaxially stretched film is preferably used as the film.

The polyester film preferably has a thickness of 6 to 75 μm. 10 to 75 μm, especially 1
It is preferably 5 to 50 μm. If the thickness is less than 6 μm, breakage or the like tends to occur during processing, while if it exceeds 75 μm, it is uneconomical because of excessive quality.

In producing a polyester film for metal laminating obtained by applying the coating composition of the present invention to the above polyester film, a conventionally known coating method can be applied. For example, roll coating method,
The gravure coating method, roll brushing method, spray coating method, air knife coating method, curtain coating method and the like can be applied alone or in combination. After coating, the solvent is removed by heating according to a conventional method. The coating composition may be applied to a biaxially stretched polyester film, or may be applied to an unstretched film or a longitudinally uniaxially stretched film and then further stretched. The composition can be applied to one side of the polyester film, but may be applied to both sides.

The thickness of the applied polycarbonate layer or resin composition layer is 0.1 to 5 μm. Thickness is 0.1 μm
If the thickness is thinner, the adhesion to the metal will be insufficient, and the impact resistance of the polycarbonate cannot be expressed. If it is thicker than 5 μm, the coating will be difficult and the economy will be poor. The film thickness of the polycarbonate or resin composition is
Preferably 0.2 to 4 μm, particularly preferably 0.3 to 3
μm.

The above-mentioned polyester film for metal laminating has a reduction rate of elongation of 30% or less after being immersed in water at 50 ° C. for 24 hours because the reduction rate of elongation when immersed in water is small. Is preferred. Such a polyester film is laminated with a metal and has good impact resistance with time when immersed in water, for example. The elongation reduction rate is more preferably 25% or less, and further preferably the elongation reduction rate is 20% or less.

As the metal plate to which the polyester film having the polycarbonate layer or the resin composition layer formed thereon is laminated, a plate made of tin plate, tin-free steel, aluminum or the like is suitable. When the film is attached to the metal plate, the coating layer, that is, the polycarbonate resin or the resin composition layer is laminated so as to be in contact with the metal plate. Lamination method is not particularly limited and conventionally known methods can be applied, but a method of heating a metal plate to a temperature not lower than the softening point of a polycarbonate resin or a resin composition and, if necessary, laminating with a preheated film and then cooling is preferably cited. You can

The polyester film for metal laminate thus obtained is preferably laminated with a steel plate, shocked, and then subjected to electrical conduction (impact resistance test), with a current value of 0.1 mA or less. It shows excellent impact resistance over time, which is only shown. Such a film is preferably used for a metal container produced by deep drawing.

[0062]

The coating composition of the present invention is extremely useful as an adhesive layer between polyester and a metal plate. Therefore, the polyester film coated with this has excellent adhesion to a metal plate, and when laminated to a metal plate,
It has good impact resistance and is especially useful for laminated steel sheet applications such as for can manufacturing.

[0063]

The present invention will be described in more detail with reference to examples, but the present invention is not limited to the examples. In the examples, "part" means "part by weight".

(I) Viscosity average molecular weight (Mv) of polycarbonate It was calculated from the intrinsic viscosity ([η]) measured in a methylene chloride solution using the following Schnell formula.

[0065]

[Equation 1]

(Ii) Terminal OH group content of polycarbonate The quantity was determined by colorimetric measurement (described in Die Makromol. Chem. 88 (1965) 215) by the interaction between TiCl ₄ and terminal OH groups.

(Iii) Peel strength The same two films are superposed so that the polycarbonate resin layer or the resin composition layer consisting of polycarbonate and polyester whose peel strength is to be evaluated is on the outside (the side in contact with the metal plate). Laminate with steel plate and evaluate.
The method of laminating is to stack this film between two 210 μm-thick steel plates treated with electrolytic chromic acid.
It was laminated with a steel plate by holding it at a pressure of 20 kg / cm ² for 30 seconds with a hot press machine at 5 ° C.
A test piece was prepared by cutting the laminated plate into a size having a width of 10 mm and a length of 50 mm. This test piece has one end 2
The release agent was attached to 0 mm in advance so that the laminate plate could be easily peeled off.

20 of the side of the test piece to which the release agent was attached
Remove the two steel plates in the opposite direction at the mm part
Fix both ends of the peeled part with a tensile tester,
The peel strength was measured at a pulling speed of 20 mm / min. (J
According to ISK6854).

(Iv) Measurement of melting point (Tm) and glass transition temperature (Tg) Both Tm and Tg were measured by DSC.

(V) Impact resistance with time A laminated plate is produced from one film and one steel plate in the same manner as described in (iii). 50 ° C after production
Keep in water for 24 hours. Thereafter, an impact deformation test is performed on this laminated plate according to the method described in JIS K5400. That is, a shooting die having a radius of curvature of 5 mm is set on the upper surface of the laminated plate on which the film is not laminated, and a weight having a mass of 200 g is gravity dropped from the position of 20 cm in height onto the shooting die. At this time, a rubber plate having a thickness of 5 mm is installed under the laminate plate.

After the impact deformation test, one electrode was applied to the metal surface of the laminated plate on which the film was not laminated, and 1 was placed on the film surface of the other laminated plate at the position (convex portion) where the weight was dropped. Apply a cotton soaked with a% saline solution and apply the other electrode to the cotton. A voltage of 6 V is applied and the current value at that time is measured. Current value (mA)
The smaller the value, the better the impact resistance over time.

(Vi) Reduction rate of film elongation The film was immersed in water at 50 ° C. for 24 hours, and the elongation before and after immersion was calculated and calculated by the following formula.

[0073]

[Equation 2]

[Examples 1 to 6 and Comparative Examples 1 and 2] (Production of Polycarbonate) 216 parts of diphenyl carbonate, 228 parts of bisphenol A and 0.05 part of diNa salt of bisphenol A were stirred with a stirrer and nitrogen gas. The reaction system was replaced with nitrogen by repeating the procedure of charging in a reaction vessel equipped with a vacuum distillation system having an introduction port and introducing nitrogen gas after vacuum deaeration at room temperature three times. Then, under normal pressure 1
After heating and reacting at 90 ° C. for 30 minutes, the pressure was gradually reduced at the same temperature, and after 60 minutes, the pressure was adjusted to 50 mmHg. Further, the reaction temperature was raised from 190 ° C. to 290 ° C. over about 60 minutes, and at the same time, the degree of vacuum was reduced from 50 mmHg to 1 mmHg or less. As the reaction progressed, phenol generated by the reaction was distilled. Reaction for 40 minutes under the same conditions, viscosity average molecular weight (Mv)
A polycarbonate resin having a viscosity of 26000 and a terminal OH amount of 73 eq / 10 ⁶ g was obtained.

(Production of Polyester Film) Polyethylene terephthalate copolymerized with the components shown in Table 1 (containing 0.3% by weight of titanium dioxide having an intrinsic viscosity of 0.64, a particle size ratio of 1.1 and an average particle size of 0.3 μm). Was dried and melted by a conventional method, then extruded from a die and rapidly solidified to prepare an unstretched film. Then, this unstretched film is heated to 110 ° C.
Then, the film was longitudinally stretched to 3.1 times, then horizontally stretched at 125 ° C. to 3 times, and heat set at 190 ° C. to obtain 6 kinds of biaxially oriented films. The thickness of each of the obtained films was 25 μm.

A predetermined amount (shown in Table 1) of the polycarbonate and polyepoxy compound (“Epicoat” 828, manufactured by Yuka Shell Epoxy Co., Ltd.) produced above was dissolved in 100 parts of methylene chloride to prepare a coating composition. Manufactured. This was coated on the above polyester film by using a bar coater, and then at 50 ° C for 3 minutes and then at 100 ° C for 5
A polycarbonate layer having a film thickness of 2 μm was formed by heat treatment for 6 minutes to produce 6 kinds of multilayer films. In addition, Table 1 also shows, as Comparative Examples 1 and 2, only the polyester films on which the polycarbonate layer is not formed.

[0077]

[Table 1]

When the elongation reduction rate of these films was determined according to the above method (vi), the reduction rate was low (Table 2).

Further, this film is formed by the above (iii),
When laminated with a steel plate according to the method (v) and the peel strength and the impact resistance with time of this laminated plate were measured, it was found that as shown in Table 2, all were excellent. The lamination was performed so that the polycarbonate layer of the film was in contact with the metal.

[0080]

[Table 2]

[Example 7] 10 parts of the polycarbonate prepared in Example 1 was dissolved in 100 parts of 1,3-dioxolane to prepare a coating composition.
It was coated on a 5 mm tin-free steel using a bar coater and heat-treated at 70 ° C. for 1 minute and then at 110 ° C. for 5 minutes to form a polycarbonate layer having a thickness of about 3 μm. The same treatment was applied to the opposite surface of the tin-free steel plate to obtain a tin-free steel plate having a polycarbonate layer on both sides. Then heat it to 250 ° C,
The polyester film used in Example 1 was laminated on both sides. When the obtained laminates were evaluated in the same manner as in Examples 1 to 6 above, both the peel strength and the impact resistance with time were good.

[Examples 8 to 14 and Comparative Examples 3 to 4] (Production of Polycarbonate) 216 parts of diphenyl carbonate, 228 parts of bisphenol A and 0.05 part of diNa salt of bisphenol A were stirred with a stirrer and nitrogen gas. The reaction system was replaced with nitrogen by repeating the procedure of charging in a reaction vessel equipped with a vacuum distillation system having an introduction port and introducing nitrogen gas after vacuum deaeration at room temperature three times. Then, under normal pressure 1
After heating and reacting at 90 ° C. for 30 minutes, the pressure was gradually reduced at the same temperature, and after 60 minutes, the pressure was adjusted to 50 mmHg. Further, the reaction temperature was raised from 190 ° C. to 290 ° C. over about 60 minutes, and at the same time, the degree of vacuum was reduced from 50 mmHg to 1 mmHg or less. As the reaction progressed, phenol generated by the reaction was distilled. Reaction for 70 minutes under the same conditions, viscosity average molecular weight (Mv)
A polycarbonate resin having 28,000 and a terminal OH amount of 48 eq / 10 ⁶ g was obtained.

A predetermined amount of this polycarbonate and polyester was dried by a conventional method and then drive blended,
Melting and kneading were carried out using a 30 mmφ co-rotating twin-screw extruder (PCM-30 manufactured by Ikegai Tekko KK) to produce three types of resin compositions (a), (b) and (c). Table 3 shows the type of each component, the amount used, and the blending conditions.

[0084]

[Table 3]

10 parts of each of the obtained three kinds of resin compositions was dissolved in 100 parts of 1,3-dioxolane, and 3 parts were prepared.
A variety of coating compositions were prepared.

(Production of Polyester Film) Polyethylene terephthalate (containing 0.3% by weight of titanium dioxide having an intrinsic viscosity of 0.64 and an average particle size of 0.3 μm) containing the components shown in Table 4 as a copolymerization component was prepared by a conventional method. After drying and melting, it was extruded from a die and rapidly solidified to prepare an unstretched film. Then, this unstretched film is
After longitudinally stretching at 3.1 ° C at 3.1 times, transverse stretching at 120 to 130 ° C at 3 times and heat setting at 190 ° C were performed to obtain a biaxially oriented film. The thickness of the obtained film was 25 μm.

This film was prepared as described above (a),
The coating compositions (b) and (c) are applied using a bar coater, and heat-dried with hot air at 100 ° C. for 1 minute and 120 ° C. for 5 minutes to obtain a resin composition having a film thickness of about 2 μm. Layers were formed. In Table 4, Comparative Examples 3 and 4 are also shown for only the polyester film.

[0088]

[Table 4]

When the elongation reduction rate of these films was determined according to the above method (vi), the reduction rate was low. (Table 5).

Further, this film is formed by the above (iii),
When laminated with a steel plate according to the method of (v) and the peel strength and the impact resistance with time of this laminated plate were measured, as shown in Table 5, it was found that all were excellent. The lamination was performed so that the resin composition layer of this film was in contact with the metal.

[0091]

[Table 5]

[Example 15] (a) prepared in Example 8
The coating composition of 1 is applied to a 0.25 mm thick tin-free steel using a bar coater,
The resin composition layer having a film thickness of about 2 μm was formed by heating with hot air at 1 ° C. for 1 minute and then at 120 ° C. for 3 minutes. The same treatment was applied to the opposite surface of the tin-free steel plate to obtain a tin-free steel plate having blend polymer layers on both sides. Next, this was heated to 250 ° C., and the polyester film used in Example 8 was laminated on both sides. When the obtained laminated plate was evaluated by the same method as in Examples 8 to 14, both the peel strength and the impact resistance with time were good.

Claims (3)

[Claims] 1. A repeating unit of the following formula (1):
60-100% by weight of polycarbonate (A) having an amount of terminal OH groups of 20 eq / 10 ⁶ g or more and a viscosity average molecular weight of 10,000-40,000, and 70 mol% or more of the acid component are terephthalic acid and / or isophthalic acid. , 70 mol% or more of the diol component is ethylene glycol and /
Or a polycarbonate resin or resin composition comprising 0 to 40% by weight of polyester (B) which is tetramethylene glycol, and a boiling point of 30 to 150 ° C. under normal pressure, which is non-reactive with the resin or the resin composition. A coating composition comprising an organic solvent and containing 1 to 30 parts by weight of the resin or the resin composition with respect to 100 parts by weight of the organic solvent. [Chemical 1] [Wherein R ₁ and R ₂ are each independently selected from a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, and a cycloalkyl group having 5 to 6 carbon atoms, and R ₁ and R ₂ are bonded to each other. May be. R ₃ and R ₄ are each independently selected from an alkyl group having 1 to 5 carbon atoms, a halogen atom and a phenyl group, and m and n are each independently 0, 1 or 2. ] 2. When the coating composition according to claim 1 comprises 100% by weight of the polycarbonate (A) and the organic solvent, a polyepoxy compound containing two or more epoxy groups in the molecule with respect to the polycarbonate. 0.1% to 10% by weight of the composition was added to the coating composition. 3. A repeating unit of the following formula (1):
60-100% by weight of polycarbonate (A) having an amount of terminal OH groups of 20 eq / 10 ⁶ g or more and a viscosity average molecular weight of 10,000-40,000, and 70 mol% or more of the acid component are terephthalic acid and / or isophthalic acid. , 70 mol% or more of the diol component is ethylene glycol and /
Or a polycarbonate resin or resin composition comprising 0 to 40% by weight of polyester (B) which is tetramethylene glycol, and a boiling point of 30 to 150 ° C. under normal pressure, which is non-reactive with the resin or the resin composition. A coating composition composed of an organic solvent and containing 1 to 30 parts by weight of the resin or the resin composition per 100 parts by weight of the organic solvent is polyethylene terephthalate or having a melting point of 2
Coated polyethylene terephthalate having a temperature of more than 00 ° C. and applied to a film having a thickness of 5 to 75 μm.
A method for producing a polyester film for metal laminating, comprising forming a polycarbonate resin layer or a resin composition layer having a thickness of 5 μm. [Chemical 2] [Wherein R ₁ and R ₂ are each independently selected from a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, and a cycloalkyl group having 5 to 6 carbon atoms, and R ₁ and R ₂ are bonded to each other. May be. R ₃ and R ₄ are each independently selected from an alkyl group having 1 to 5 carbon atoms, a halogen atom and a phenyl group, and m and n are each independently 0, 1 or 2. ]