JP2023034393A - Polyester resin composition, method for producing laminate, and method for producing polyester resin film - Google Patents

Abstract

To obtain a polyester resin which has low dielectric characteristics at high frequencies, excellent adhesion to metals, and excellent film strength when formed into a film.SOLUTION: A polyester resin composition contains: a polyester resin comprising the following structural units (I) and (II) as essential components and containing 1-40 mol% of (I); and a medium. (R1 represents H, a C1-5 alkyl, an aryl or CF3; Ar represents a benzene, naphthalene, biphenyl or triphenyl structure (which may have a C1-5 alkyl, an aryl, a halogen or CF3 as a substituent); X1 and X2 each represent O, CO or NH; and Ar2 represents p- or m-phenylene or 2,6- or 2,7-naphthalene.)SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to polyester resin compositions, molded articles, and laminates. More specifically, the present invention relates to polyester resins, polyester resin molded articles such as films and sheets obtained using the polyester resins, and laminates.

With the recent increase in demand for mobile terminals and communication base stations, the demand for resins used in printed circuit boards such as rigid boards and flexible boards is increasing. Furthermore, in recent years, the fifth generation mobile communication "5G" has started to be used, and resins for these substrates are required to have high performance such as low dielectric properties at high frequencies.

As a technique for imparting low dielectric properties to a resin, a technique for suppressing the mobility of the resin when exposed to electromagnetic waves is effective. Liquid crystalline polyester resins are resins with excellent dielectric properties because the mobility of molecular chains is suppressed by arranging and packing the molecular chains due to the liquid crystal structure. As an example of a liquid crystal polyester resin with a further reduced dielectric, a liquid crystal polyester resin having a certain amount of structural units composed of 6-hydroxy-2-naphthoic acid has been proposed (eg, Patent Document 1).

When a resin is used as a printed circuit board such as the rigid board or flexible board described above, the resin is molded into a film. Especially in laminates in which a resin film is bonded to a metal foil such as copper, from the viewpoint of improving productivity and durability of the laminate, the metal adhesion of the resin and the film strength are considered important. A typical method for manufacturing a laminate is to laminate a resin film and a metal foil and bond them together by thermocompression. Since the properties are deteriorated, a method of coating a resin solution composition on a metal foil to form a laminate has also been proposed (for example, Patent Document 2). In the technique using such a solution, the resin must have high solubility and dispersibility in the solvent.

Various properties of polyester resin films can be improved by copolymerizing specific structures. As an example of improving film properties by introducing a specific structure, in Patent Document 3, a polyarylate resin film composed of bisphenol residues and aromatic dicarboxylic acid residues has excellent heat resistance, light transparency and flame retardancy. Patent document 4 discloses that an aromatic copolyester composed of a bisphenol and a naphthalene structure forms a film having excellent physical properties. Similarly, Patent Document 5 discloses an aromatic polyester having a bisphenol structure, which is said to be easy to mold and have excellent physical properties.

Japanese Patent Application Laid-Open No. 2004-196930 Japanese Unexamined Patent Publication No. 2004-315678 WO2014/024787 JP-A-2-255719 JP-A-6-49189

The methods described in Patent Documents 1 and 2 have an effect on the dielectric loss tangent of the polyester resin, and the anisotropy is eliminated by forming a laminate from a resin solution composition. Insufficient low dielectric properties in the high frequency band called wave. Patent Documents 3 to 5 describe techniques for improving various film properties by copolymerizing a specific structure, but there is no mention of dielectric properties, and the high level required for recent electrical and electronic parts is achieved. It has been difficult to achieve both low dielectric properties and film strength in the high frequency band.

An object of the present invention is to provide a polyester resin composition which, when formed into a film, has low dielectric properties at high frequencies and is excellent in metal adhesion and film strength, a laminate obtained therefrom, and a polyester resin film. and

As a result of intensive studies to solve the above problems, the present inventors have found that a polyester resin containing a specific amount of structural units derived from an aromatic hydroxycarboxylic acid while having a specific structure in the main chain and a medium. The present inventors have found that the polyester resin composition, when made into a film, has low dielectric properties at high frequencies and is excellent in metal adhesion and film strength.

Accordingly, the present invention is as follows:
(1) A polyester resin containing the following structural unit (I) and structural unit (II) as essential components, wherein the content of the structural unit (I) is 1 to 40 mol% relative to 100 mol% of the total structural units of the polyester resin. A polyester resin composition comprising a polyester resin and a medium.

(R ¹ represents one selected from a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an aryl group, and a trifluoromethyl group (CF ₃ ); Ar represents benzene, naphthalene, biphenyl, and triphenyl; represents any selected aromatic ring structure, and these aromatic rings have a substituent of an alkyl group having 1 to 5 carbon atoms, an aryl group, a halogen atom, and a trifluoromethyl group (CF ₃ ); X ¹ and X ² each independently represent any one of O, CO and NH.)
(Ar ² represents any one selected from 1,4-phenylene, 1,3-phenylene, 2,6-naphthalene and 2,7-naphthalene.)
(2) The polyester resin composition according to (1), wherein the structural unit (I) is a structural unit shown in (i) below.

(X ¹ and X ² each independently represent O, CO, or NH; R ¹ is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an aryl group, or a trifluoromethyl group (CF ₃ ), and R ² and R ³ each independently represent any one selected from an alkyl group having 1 to 5 carbon atoms, an aryl group, a halogen atom, and a trifluoromethyl group (CF ₃ ). , n and m each independently represent an integer of 0 to 4.)
(3) A method for producing a laminate, comprising coating the polyester resin composition according to (1) or (2) on a support and removing the medium to obtain a laminate.
(4) A method for producing a polyester resin film, comprising producing a laminate by the production method described in (3) and then removing the support.

When the polyester resin composition of the present invention is formed into a film, it has low dielectric properties at high frequencies and is excellent in metal adhesion and strength. Films obtained from such resins are suitable for laminates used in electrical/electronic parts, flexible printed wiring boards in mechanical parts, semiconductor packages, and the like.

The present invention will be described in detail below.

<Polyester resin>
The polyester resin of the polyester resin composition in the present invention is a polymer in which each structural unit is linked via an ester bond. selected as the unit.

Next, structural units constituting the polyester resin will be described.

The polyester resin of the present invention contains the following structural unit (I) as an essential unit.

(R ¹ represents one selected from a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an aryl group, and a trifluoromethyl group (CF ₃ ); Ar represents benzene, naphthalene, biphenyl, and triphenyl; represents any selected aromatic ring structure, and these aromatic rings are any substituent selected from alkyl groups having 1 to 5 carbon atoms, aryl groups, halogen atoms, and trifluoromethyl groups (CF ₃ ) X ¹ and X ² each independently represent O, CO, or NH.)

Structural unit (I) has a trifluoromethyl group (CF ₃ ). Fluorine atoms have high electronegativity and have the effect of attracting surrounding electrons and suppressing electron mobility. Therefore, the presence of the structural unit (I) in the main chain results in low dielectric properties at high frequencies. In addition, the fluorine atom has a larger atomic radius than the hydrogen atom, and the presence of the trifluoromethyl group in the center of the propane structure shown in (A) suppresses the rotation of the propane structure due to steric hindrance, resulting in a stronger structure. becomes. Furthermore, the bend structure derived from propane alleviates the formation of a highly linear long chain formed by a structural unit derived from an aromatic hydroxycarboxylic acid described later, suppresses the formation of foreign substances derived from the site, and has excellent film properties. It becomes a polyester resin. Furthermore, the introduction of the bent structure facilitates fine dispersion or dissolution of the polyester resin in the medium described later, and when it is formed into a film, the metal adhesion is further improved.

R ¹ in structural unit (I) can be selected from a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an aryl group, and a trifluoromethyl group. Therefore, a trifluoromethyl group is preferred.
The content of the structural unit (I) is 1 to 40 mol% with respect to 100 mol% of the total structural units of the polyester resin. If it is lower than 1 mol %, the dielectric properties at high frequencies and the dispersibility in the medium are lowered, and the metal adhesion is lowered. If it is more than 40 mol %, the strength will decrease. From the viewpoint of dielectric properties and metal adhesion at high frequencies, it is preferably 5 mol % or more, more preferably 8 mol % or more, and even more preferably 12 mol % or more. From the viewpoint of increasing the strength, it is preferably 35 mol% or less, more preferably 32 mol% or less, and even more preferably 28 mol% or less.

From the viewpoint of facilitating the introduction of the structural unit (I) into the main chain, the structural unit (I) is preferably a structural unit shown in (i) below.

(X ¹ and X ² each independently represent O, CO, or NH; R ¹ is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an aryl group, or a trifluoromethyl group (CF ₃ ), wherein R ² and R ³ each independently represent an alkyl group having 1 to 5 carbon atoms, an aryl group, a halogen atom, or a trifluoromethyl group (CF ₃ ), n and m are Each independently represents an integer from 0 to 4.)

Structural unit (I) is, for example, 2,2-bis(4-hydroxyphenyl)hexafluoropropane, 2,2-bis(4-carboxyphenyl)hexafluoropropane, 2,2-bis(4-aminophenyl) Hexafluoropropane, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 4,4'-(hexafluoroisopropylidene) Bis(1,2-benzenedicarboxylic acid), 1,1,1-trifluoro-2,2-bis(4-hydroxyphenyl)propane, 1,1,1-trifluoro-2,2-bis(4- hydroxyphenyl)ethane, etc. can be introduced as a monomer. 2,2-bis(4-hydroxyphenyl)hexafluoropropane, 2,2-bis(4-carboxyphenyl)hexafluoropropane, 2,2-bis(4-aminophenyl) from the viewpoint of polymerizability and dielectric properties at high frequencies ) It is preferable to use hexafluoropropane as a monomer, and it is particularly preferable to use 2,2-bis(4-hydroxyphenyl)hexafluoropropane as a monomer.

The polyester resin of the present invention contains, as an oxycarbonyl unit, a structural unit (II) derived from the following aromatic hydroxycarboxylic acid as an essential unit. Structural unit (II) has excellent polymerizability, and inclusion of (II) improves low dielectric properties and strength at high frequencies.

(Ar ² represents any one selected from 1,4-phenylene, 1,3-phenylene, 2,6-naphthalene and 2,7-naphthalene.)

Ar ² in the structural unit (II) is any one selected from 1,4-phenylene, 1,3-phenylene, 2,6-naphthalene and 2,7-naphthalene, from the viewpoint of polymerizability and availability Therefore, 1,4-phenylene and 2,6-naphthalene are preferred. That is, structural units derived from p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid are preferred. Structural unit (II) may be used in combination with p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid.

When p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid are used in combination as the structural unit (II), the content of 6-hydroxy-2-naphthoic acid is higher than the content of p-hydroxybenzoic acid. is preferably large.

The content of the structural unit (II) relative to 100 mol % of all structural units in the polyester resin is preferably 30 mol % or more from the viewpoint of low dielectric properties at high frequencies, film strength, and dispersibility in media. It is more preferably 35 mol % or more, more preferably 40 mol % or more, even more preferably 45 mol % or more, and particularly preferably 50 mol % or more. Moreover, it is preferably 80 mol % or less, more preferably 77 mol % or less, even more preferably 75 mol % or less, and particularly preferably 72 mol % or less.

The polyester resin of the present invention may contain a structural unit derived from an aromatic or aliphatic diol as a dioxy unit different from the structural unit (I), and the dioxy unit is 0.1 per 100 mol % of the total structural units of the polyester resin. It is preferably ~30 mol %. By setting it to such a range, it is possible to reduce the generation of infusible foreign matter derived from the long chain of the structural unit (II), improve the dispersibility of the polyester resin in the medium, and further improve the metal adhesion and strength. be able to. 0.5 mol % or more is preferable, 1 mol % or more is preferable, and 1.2 mol % or more is more preferable. From the viewpoint of excellent strength, the content is preferably 25 mol% or less, more preferably 22 mol% or less, even more preferably 20 mol% or less, and particularly preferably 18 mol% or less.

Specific examples of aromatic or aliphatic diols include 4,4′-dihydroxybiphenyl, hydroquinone, resorcinol, t-butylhydroquinone, phenylhydroquinone, chlorohydroquinone, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 3 ,4'-dihydroxybiphenyl, 2,2-bis(4-hydroxyphenyl)propane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfide, 4,4' - Structural units derived from aromatic diols such as dihydroxybenzophenone, structural units derived from 2,2'-bis(4-hydroxyphenyl)propane, ethylene glycol, propylene glycol, 1,4-butanediol, 1,6- Structural units generated from aliphatic diols such as hexanediol and neopentyl glycol, and structural units generated from alicyclic diols such as 1,4-cyclohexanediol and 1,4-cyclohexanedimethanol. Structural units formed from 4,4'-dihydroxybiphenyl, hydroquinone, and ethylene glycol are preferred from the viewpoints of good polymerizability, low dielectric properties at high frequencies, and excellent strength. Note that these structural units may be used in combination.

The polyester resin of the present invention can contain a structural unit derived from a dicarbonyl unit different from the structural unit (I). Specific examples of dicarbonyl units include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, 3,3′-diphenyldicarboxylic acid, 2,2′-diphenyldicarboxylic acid, Aromas such as 1,2-bis(phenoxy)ethane-4,4'-dicarboxylic acid, 1,2-bis(2-chlorophenoxy)ethane-4,4'-dicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid Structural units generated from group dicarboxylic acids, structural units generated from aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, hexahydroterephthalic acid, 1,4-cyclohexanedicarboxylic acid, 1,3- Examples include structural units generated from alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid. Structural units generated from aromatic dicarboxylic acids are preferred from the viewpoints of good polymerizability, low dielectric properties at high frequencies, and excellent strength. Among them, structural units generated from terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid are preferred. Especially preferred.

In addition to the structural units described above, the polyester resin may further contain structural units formed from p-aminobenzoic acid, p-aminophenol, etc., as long as the properties are not impaired.

The raw material monomers constituting each structural unit are not particularly limited as long as they have a structure capable of forming each structural unit. In addition, acylated products of hydroxyl groups of such monomers, esterified products of carboxyl groups, acid halides, carboxylic acid derivatives such as acid anhydrides, and the like may also be used.

A method for calculating the content of each structural unit in the polyester resin is shown below. First, after pulverizing the polyester resin, tetramethylammonium hydroxide is added, and the pyrolysis GC/MS measurement is performed using Shimadzu's GCMS-QP5050A. The content of structural units not detected or below the detection limit is calculated as 0 mol %.

The melting point (Tm) of the polyester resin is preferably 350° C. or less from the viewpoint of easy film formation by the method described later, low dielectric properties at high frequencies, and excellent strength. 340° C. or lower is more preferable, and 330° C. or lower is particularly preferable.

The melting point (Tg) of the polyester resin is preferably 110° C. or higher, more preferably 120° C. or higher, and even more preferably 130° C. or higher, from the viewpoints of low dielectric properties at high frequencies, high elastic modulus and high strength. The melting point (Tg) of the polyester resin is preferably 200° C. or lower, more preferably 190° C. or lower, still more preferably 180° C. or lower, and most preferably 170° C. or lower, from the viewpoint of facilitating film formation by the method described later.

<Method for producing polyester resin>
The method for producing the polyester resin used in the present invention is not particularly limited, and it can be produced according to a known polyester polycondensation method. Specifically, structural units derived from p-hydroxybenzoic acid, structural units derived from 6-hydroxy-2-naphthoic acid, structural units derived from 2,2-bis(4-hydroxyphenyl)hexafluoropropane, Taking a polyester resin composed of structural units derived from 4,4′-dihydroxybiphenyl, structural units derived from terephthalic acid, and structural units derived from ethylene glycol, the following methods can be mentioned.

(1) p-acetoxybenzoic acid, 6-acetoxy-2-naphthoic acid, 2,2-bis(4-acetoxyphenyl)hexafluoropropane, 4,4′-diacetoxybiphenyl, terephthalic acid, and polyethylene terephthalate— A method for producing a polyester resin from a polyester polymer or oligomer such as bis(β-hydroxyethyl) terephthalate by a deacetic acid polycondensation reaction.

(2) p-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 2,2-bis(4-hydroxyphenyl)hexafluoropropane, 4,4'-dihydroxybiphenyl, terephthalic acid, and polyethylene terephthalate A method for producing a polyester resin by reacting a polyester polymer or oligomer such as bis(β-hydroxyethyl) terephthalate with acetic anhydride to acetylate the phenolic hydroxyl groups, followed by a deacetic acid polycondensation reaction.

(3) A method using 1,2-bis(6-hydroxy-2-naphthoyl)ethane as a part of the starting material in the production method of (1) or (2).

Among them, the method (2) is easy to control the degree of polymerization of the polyester resin, and can suppress the long chain of the above-mentioned aromatic hydroxycarboxylic acid (structural unit (II) or (III)). It is preferably used because it is superior in terms of

When the polyester resin of the present invention is produced by the method (2), the temperature of the reaction for acetylating the phenolic hydroxyl group (acetylation reaction) is usually in the range of 130 to 210°C, preferably 130 to 210°C. It is in the range of 150°C. The acetylation reaction time is usually 30 minutes or more from the viewpoint of polymerization reactivity, but the above-mentioned aromatic hydroxycarboxylic acid (structural unit (II) or (III)) can suppress the long chain and has a high elastic modulus. And from the viewpoint of high strength and improved film formability, the temperature is preferably 130 to 150° C. for 2 hours or more, more preferably 2 hours and 30 minutes or more. On the other hand, the acetylation reaction time is usually 6 hours or less from the viewpoint of productivity, but is preferably 4 hours or less, more preferably 3 hours and 30 minutes or less, from the viewpoint of achieving high elastic modulus and high strength.

From the viewpoint of polymerization reactivity, the amount of acetic anhydride used in the acetylation reaction is usually at least 1.00 equivalents of the total phenolic hydroxyl groups in the polyester raw material. 1.08 equivalents or more are preferable, and 1.10 equivalents or more are more preferable from the viewpoint of reducing the amount of divalent hydroxyl groups and providing low dielectric properties at high frequencies. On the other hand, the amount of acetic anhydride to be used is usually 1.20 equivalents or less, preferably 1.14 equivalents or less, more preferably 1.13 equivalents or less, from the viewpoint of suppressing foreign substances derived from chains of aromatic hydroxycarboxylic acids. more preferred.

As a method for producing the polyester resin used in the present invention, it is also possible to complete the polycondensation reaction by a solid phase polymerization method. Examples of solid-phase polymerization treatment include the following methods. First, a polyester resin polymer or oligomer is pulverized by a pulverizer. The pulverized polymer or oligomer is heated under a stream of nitrogen or under reduced pressure to polycondense to the desired degree of polymerization to complete the reaction. The heating is preferably carried out at a melting point of -50°C to -5°C for 1 to 50 hours.

The polycondensation reaction of polyester resin proceeds without a catalyst, but stannous acetate, tetrabutyl titanate, potassium acetate and sodium acetate, antimony trioxide, metal magnesium, etc. can also be used as catalysts.

<Polyester resin composition>
The polyester resin composition of the present invention contains a medium. The medium in the present invention is a substance that has a melting point and a boiling point and can take a liquid state in a certain temperature range, and includes organic solvents. Examples include halogenated hydrocarbons such as dichloromethane, chloroform, 1,1-dichloroethane, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, 1-chlorobutane, chlorobenzene, o-dichlorobenzene; halogenated alcohols such as isopropanol; halogenated phenols such as p-chlorophenol, pentachlorophenol and pentafluorophenol; ethers such as diethyl ether, tetrahydrofuran and 1,4-dioxane; ketones such as acetone and cyclohexanone; -esters such as butyrolactone; amide compounds such as N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone; urea compounds such as tetramethylurea; nitro compounds such as nitromethane and nitrobenzene; and phosphorus compounds such as hexamethylphosphoric acid amide and tri-n-butyl phosphate, and two or more thereof may be used.

From the viewpoint of dispersibility of the polyester resin, an aprotic compound, particularly an aprotic compound having no halogen atom, is preferred. As the aprotic compound, it is preferable to use an amide such as N,N-dimethylformamide, N,N-dimethylacetamide, tetramethylurea, N-methylpyrrolidone or an ester such as γ-butyrolactone. More preferred are dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone.

From the viewpoint of removability, the boiling point of the medium is preferably 220° C. or lower, more preferably 210° C. or lower. From the viewpoint of removability and film-forming properties, the temperature is preferably 50°C or higher, more preferably 60°C or higher, and particularly preferably 70°C or higher.

From the viewpoint of the film thickness of the film obtained from the polyester resin composition, the proportion of the polyester resin contained in the medium is preferably 0.1% by weight or more, and preferably 1% by weight or more, relative to the total amount of the polyester resin and the medium. is more preferable, 3% by weight or more is more preferable, and 5% by weight or more is particularly preferable. On the other hand, from the viewpoint of the dispersibility of the polyester resin, it is preferably 60% by weight or less, more preferably 50% by weight or less, even more preferably 40% by weight or less, and particularly preferably 30% by weight or less.

In the polyester resin composition of the present invention, the polyester resin may be completely or partially soluble or insoluble in the medium. When there is an insoluble component, the polyester resin in the insoluble portion preferably has a volume average particle size of 0.1 to 50 μm. The volume average particle size is preferably 35 μm or less, more preferably 20 μm or less, and even more preferably 15 μm or less, from the viewpoint of uniform surface and metal adhesion. The volume average particle diameter is measured, for example, by a wet laser diffraction/scattering method (manufactured by Nikkiso Co., Ltd., model: Microtrac MT3300EXII), with water as the dispersion medium for measurement, the refractive index of the substance being 1.53, and the refractive index of the dispersion medium being It is set to 1.333, and can be measured with a dispersion obtained by pre-dispersing the polyester resin composition in ion-exchanged water.

Further, the dispersion of the present invention may contain known fillers, additives and the like within a range that does not impair the effects of the present invention.

<Polyester resin laminate and film>
The polyester resin composition of the present invention can be used as a raw material for producing polyester resin films and laminates.

The polyester resin film of the present invention is obtained from the polyester resin composition of the present invention. For example, the polyester resin film is produced by applying the polyester resin composition of the present invention onto a support, removing the medium to obtain a laminate, and then removing the support from the obtained laminate. be able to.

The laminate of the present invention is a laminate obtained by laminating a support and a resin layer, wherein the support is laminated on at least one surface of the resin layer obtained from the polyester resin composition of the present invention. be. The laminate can be produced, for example, by the following methods (I) to (IV).

(I) A method of removing the medium after applying the polyester resin composition of the present invention onto a support.

(II) A method of attaching the film produced by the above method to a support by thermocompression bonding.

(III) A method of adhering the film produced by the above method to a support with an adhesive.

(IV) A method of forming a support on the film produced by the above method by vapor deposition.

The method (I) is preferable from the viewpoint that a resin layer having a uniform thickness can be easily formed.

A method for producing a laminate by the above method (I) will be described below.

Examples of the method for applying the polyester resin composition to the support include roller coating, dip coating, spray coating, spinner coating, curtain coating, slot coating and screen printing. , the polyester resin composition is evenly and uniformly cast on the support by these means to form a coating film.

Subsequently, a polyester resin layer is formed on the surface of the support by removing the medium in the coating film. The method of removing the medium is preferably carried out by evaporation of the medium. Methods for evaporating the medium include methods such as heating, pressure reduction, and ventilation. From the viewpoint of suppressing rapid evaporation of the medium and obtaining a film having a uniform thickness, it is preferable to remove the medium by heating. The heating temperature is not particularly limited as long as it is a temperature at which the medium volatilizes, but from the viewpoint of suppressing deformation after heat treatment, it is preferably a temperature lower than the boiling point of the medium. Therefore, it is preferable to heat at a temperature above room temperature and below the boiling point of the medium.

After forming the laminate in this manner, heat treatment may be performed as necessary. The heat treatment method is not particularly limited, and can be performed using a hot air oven, a vacuum oven, a hot plate, or the like. Further, the heat treatment may be performed under atmospheric pressure, or under increased pressure or reduced pressure within a range in which the support and the polyester resin are not deteriorated. Moreover, from the viewpoint of suppressing deterioration of the polyester resin, it is preferable to perform the heat treatment in an inert gas atmosphere. The heat treatment temperature is appropriately determined according to the properties, but the melting point (Tm) of the polyester resin is preferably in the range of -5°C to +30°C, more preferably in the range of ±0°C to +20°C.

Examples of the structure of the laminate thus obtained include a two-layer structure of a film and a support, a three-layer structure in which a support is laminated on both sides of a film, and a three-layer structure in which a film is laminated on both sides of a support. A layered structure, and a multi-layered structure in which four or more layers of films and supports are alternately laminated can be mentioned.

The polyester resin film or laminate obtained by the above method is, for example, various computers, OA equipment, flexible printed wiring boards mounted with electrical / electronic components represented by AV equipment, electrical / electronic components, rigid printed wiring Circuit substrates such as plates; semiconductor packages used for automotive semiconductors, industrial semiconductors, etc.; transparent conductive film substrates, polarizing film substrates, packaging films for various cooked foods and microwave oven heating, electromagnetic wave shielding It can be used for films, antibacterial films, gas separation films and the like. Since a film with a uniform thickness without cracks can be obtained, it is suitably used for circuit boards such as flexible printed wiring boards and rigid printed wiring boards that use laminates characterized by laminating multiple sheets, and semiconductor packages. be.

EXAMPLES The present invention will be described below using examples, but the present invention is not limited by the examples. In the examples, the composition and property evaluation of the polyester resin were measured by the following methods.

(1) Composition analysis of polyester resin To 0.1 mg of pulverized polyester resin, 2 μL of tetramethylammonium hydroxide 25% methanol solution is added, and pyrolysis GC / MS measurement is performed using Shimadzu GCMS-QP5050A. The content (mol%) of each structural unit with respect to 100 mol% of the total structural units of and the ratio (%) of the following structural unit (II) in all structural units derived from aromatic hydroxycarboxylic acid were calculated.

(2) Measurement of melting point (Tm) and glass transition temperature (Tg) of polyester Polyester resin was heated from room temperature at 20°C/min using a differential scanning calorimeter (DSC) device (Q200 manufactured by TA Instruments). After observing the endothermic peak temperature (Tm ₁ ) observed at the time, it was held at a temperature of Tm ₁ +20 ° C. for 5 minutes, then cooled once to room temperature under a temperature decrease condition of 20 ° C./min, and again increased by 20 ° C./min. The endothermic peak temperature in the temperature rise curve observed when heated under high temperature conditions is the melting point (Tm), and the intermediate value of the two bending point temperatures derived from the glass transition is obtained, and this is the glass transition temperature (Tg). and

(3) Volume average particle size of the polyester resin in the polyester resin composition The polyester resin composition is dispersed in pure water, and a laser diffraction/light scattering particle size distribution meter Microtrac MT3300EXII (manufactured by Nikkiso Co., Ltd.) is used to determine the purity. Assuming that the refractive index of water is 1.333, the volume-based cumulative particle size distribution of the polyester resin dispersed in the polyester resin composition was measured to calculate the average particle size (D ₅₀ ).

[Example 1]
25 parts by weight of p-hydroxybenzoic acid, 1186 parts by weight of 6-hydroxy-2-naphthoic acid, and 908 parts by weight of 2,2-bis(4-hydroxyphenyl)hexafluoropropane were placed in a 5 L reaction vessel equipped with a stirring blade and a distillation tube. Parts by weight, 449 parts by weight of terephthalic acid and 1334 parts by weight of acetic anhydride (1.1 equivalents of the total phenolic hydroxyl groups) were charged and reacted at 145°C for 150 minutes with stirring under a nitrogen gas atmosphere. °C over 4 hours. After that, the polymerization temperature was maintained at 300° C., the pressure was reduced to 1.0 mmHg (133 Pa) over 1.0 hour, and the reaction was continued until the torque required for stirring reached 50 kg·cm to complete the polymerization. Next, the inside of the reaction vessel is pressurized to 2.5 kg/cm ² (0.25 MPa), and the polymer is discharged in strands through a mouthpiece having a circular discharge port with a diameter of 6 mm, and pelletized by a cutter to obtain polyester. A resin (A-1) was obtained.

A composition analysis of this polyester resin (A-1) revealed that the structural unit derived from p-hydroxybenzoic acid (structural unit (II)) was 1.6 mol%, derived from 6-hydroxy-2-naphthoic acid. The structural unit (structural unit (II)) is 53.0 mol%, the structural unit (structural unit (I)) derived from 2,2-bis(4-hydroxyphenyl)hexafluoropropane is 22.7 mol%, Structural units derived from terephthalic acid accounted for 22.7 mol %. Also, Tm was 270°C and Tg was 135°C.

The obtained polyester resin (A-1) pellets were pulverized by a coarse pulverizer to obtain a coarse powder having a volume average particle size of about 100 μm. 900 parts by weight of N-methylpyrrolidone was added to 100 parts by weight of the obtained powder, and the mixture was heated to 130° C. and stirred for 1 hour using a homogenizer (manufactured by IKA) to obtain a polyester resin composition. At this time, the volume average particle size of the polyester resin dispersed in the composition was 13 μm.

The obtained polyester resin composition was applied to the roughened surface of the copper foil using a film applicator and an automatic coating device (manufactured by BEVS) so that the thickness of the cast film was 400 μm, and the coating was carried out at 40° C. for 4 hours. After removing the dispersion medium by drying for a period of time, heat treatment was further performed by holding in a hot air oven at 260° C. for 6 hours under a nitrogen atmosphere to obtain a laminate of copper foil and polyester resin film.

[Example 2]
25 parts by weight of p-hydroxybenzoic acid, 1186 parts by weight of 6-hydroxy-2-naphthoic acid, and 757 parts by weight of 2,2-bis(4-hydroxyphenyl)hexafluoropropane were placed in a 5 L reaction vessel equipped with a stirring blade and a distillation tube. Parts by weight, 449 parts by weight of terephthalic acid, 84 parts by weight of 4,4'-dihydroxybiphenyl and 1334 parts by weight of acetic anhydride (1.1 equivalents of the total phenolic hydroxyl groups) were charged and heated to 145°C under a nitrogen gas atmosphere with stirring. After reacting for 150 minutes, the temperature was raised from 145° C. to 300° C. over 4 hours. After that, the polymerization temperature was maintained at 300° C., the pressure was reduced to 1.0 mmHg (133 Pa) over 1.0 hour, and the reaction was continued until the torque required for stirring reached 50 kg·cm to complete the polymerization. Next, the inside of the reaction vessel is pressurized to 2.5 kg/cm ² (0.25 MPa), and the polymer is discharged in strands through a mouthpiece having a circular discharge port with a diameter of 6 mm, and pelletized by a cutter to obtain polyester. A resin (A-2) was obtained.

A composition analysis of this polyester resin (A-2) revealed that the structural unit derived from p-hydroxybenzoic acid (structural unit (II)) was 1.6 mol%, derived from 6-hydroxy-2-naphthoic acid. The structural unit (structural unit (II)) is 53.0 mol%, the structural unit (structural unit (I)) derived from 2,2-bis(4-hydroxyphenyl)hexafluoropropane is 18.9 mol%, Structural units derived from 4,4'-dihydroxybiphenyl (structural units derived from aromatic diol) accounted for 3.8 mol%, and structural units derived from terephthalic acid accounted for 22.7 mol%. Also, Tm was 272°C and Tg was 138°C.

The obtained polyester resin (A-2) pellets were pulverized by a coarse pulverizer to obtain a coarse powder having a volume average particle size of about 100 μm. 900 parts by weight of N-methylpyrrolidone was added to 100 parts by weight of the obtained powder, and the mixture was heated to 130° C. and stirred for 1 hour using a homogenizer (manufactured by IKA) to obtain a polyester resin composition. At this time, the volume average particle size of the polyester resin dispersed in the composition was 11 μm.

The obtained polyester resin composition was applied to the roughened surface of the copper foil using a film applicator and an automatic coating device (manufactured by BEVS) so that the thickness of the cast film was 400 μm, and the coating was carried out at 40° C. for 4 hours. After removing the dispersion medium by drying for a period of time, heat treatment was further performed by holding in a hot air oven at 260° C. for 6 hours under a nitrogen atmosphere to obtain a laminate of copper foil and polyester resin film.

[Example 3]
25 parts by weight of p-hydroxybenzoic acid, 1186 parts by weight of 6-hydroxy-2-naphthoic acid, and 378 parts by weight of 2,2-bis(4-hydroxyphenyl)hexafluoropropane were placed in a 5 L reaction vessel equipped with a stirring blade and a distillation tube. Parts by weight, 374 parts by weight of terephthalic acid, 210 parts by weight of 4,4'-dihydroxybiphenyl and 1233 parts by weight of acetic anhydride (1.1 equivalents of the total phenolic hydroxyl groups) were charged and heated to 145°C under a nitrogen gas atmosphere with stirring. After reacting for 150 minutes, the temperature was raised from 145° C. to 300° C. over 4 hours. After that, the polymerization temperature was maintained at 300° C., the pressure was reduced to 1.0 mmHg (133 Pa) over 1.0 hour, and the reaction was continued until the torque required for stirring reached 50 kg·cm to complete the polymerization. Next, the inside of the reaction vessel is pressurized to 2.5 kg/cm ² (0.25 MPa), and the polymer is discharged in strands through a mouthpiece having a circular discharge port with a diameter of 6 mm, and pelletized by a cutter to obtain polyester. A resin (A-3) was obtained.

A composition analysis of this polyester resin (A-3) revealed that the structural unit derived from p-hydroxybenzoic acid (structural unit (II)) was 1.7 mol%, derived from 6-hydroxy-2-naphthoic acid. The structural unit (structural unit (II)) is 57.5 mol%, the structural unit (structural unit (I)) derived from 2,2-bis(4-hydroxyphenyl)hexafluoropropane is 10.2 mol%, Structural units derived from 4,4′-dihydroxybiphenyl (structural units derived from aromatic diol) accounted for 10.2 mol %, and structural units derived from terephthalic acid accounted for 20.4 mol %. Also, Tm was 268°C and Tg was 128°C.

The obtained polyester resin (A-3) pellets were pulverized by a coarse pulverizer to obtain a coarse powder having a volume average particle size of about 100 μm. 900 parts by weight of N-methylpyrrolidone was added to 100 parts by weight of the obtained powder, and the mixture was heated to 130° C. and stirred for 1 hour using a homogenizer (manufactured by IKA) to obtain a polyester resin composition. At this time, the volume average particle diameter of the polyester resin dispersed in the composition was 16 μm.

The obtained polyester resin composition was applied to the roughened surface of the copper foil using a film applicator and an automatic coating device (manufactured by BEVS) so that the thickness of the cast film was 400 μm, and the coating was carried out at 40° C. for 4 hours. After removing the dispersion medium by drying for a period of time, heat treatment was further performed by holding in a hot air oven at 250° C. for 6 hours under a nitrogen atmosphere to obtain a laminate of copper foil and polyester resin film.

[Example 4]
547 parts by weight of p-hydroxybenzoic acid, 745 parts by weight of 6-hydroxy-2-naphthoic acid, and 363 parts by weight of 2,2-bis(4-hydroxyphenyl)hexafluoropropane were placed in a 5 L reaction vessel equipped with a stirring blade and a distillation tube. Parts by weight, 179 parts by weight of terephthalic acid and 1132 parts by weight of acetic anhydride (1.1 equivalents of the total phenolic hydroxyl groups) were charged and reacted at 145°C for 150 minutes with stirring under a nitrogen gas atmosphere. °C over 4 hours. After that, the polymerization temperature was kept at 280° C., the pressure was reduced to 1.0 mmHg (133 Pa) over 1.0 hour, the reaction was continued, and the polymerization was completed when the torque required for stirring reached 35 kg·cm. Next, the inside of the reaction vessel is pressurized to 2.0 kg/cm ² (0.20 MPa), and the polymer is discharged in strand form through a mouthpiece having a circular discharge port with a diameter of 6 mm, and pelletized by a cutter to obtain polyester. A resin (A-4) was obtained.

A composition analysis of this polyester resin (A-4) revealed that the structural unit derived from p-hydroxybenzoic acid (structural unit (II)) was 39.3 mol%, derived from 6-hydroxy-2-naphthoic acid. The structural unit (structural unit (II)) is 39.3 mol%, the structural unit (structural unit (I)) derived from 2,2-bis(4-hydroxyphenyl)hexafluoropropane is 10.7 mol%, Structural units derived from terephthalic acid accounted for 10.7 mol %. Also, Tm was 240°C and Tg was 125°C.

The obtained polyester resin (A-4) pellets were pulverized by a coarse pulverizer to obtain a coarse powder having a volume average particle size of about 100 μm. 900 parts by weight of N-methylpyrrolidone was added to 100 parts by weight of the obtained powder, and the mixture was heated to 130° C. and stirred for 1 hour using a homogenizer (manufactured by IKA) to obtain a polyester resin composition. At this time, the volume average particle size of the polyester resin dispersed in the composition was 17 μm.

The obtained polyester resin composition was applied to the roughened surface of the copper foil using a film applicator and an automatic coating device (manufactured by BEVS) so that the thickness of the cast film was 400 μm, and the coating was carried out at 40° C. for 4 hours. After the dispersion medium was removed by drying for a period of time, heat treatment was further performed by holding in a hot air oven at 230° C. for 6 hours under a nitrogen atmosphere to obtain a laminate of copper foil and polyester resin film.

[Example 5]
870 parts by weight of p-hydroxybenzoic acid, 85 parts by weight of 6-hydroxy-2-naphthoic acid, and 666 parts of 2,2-bis(4-hydroxyphenyl)hexafluoropropane were placed in a 5 L reaction vessel equipped with a stirring blade and a distillation tube. Parts by weight, 404 parts by weight of terephthalic acid, 84 parts by weight of 4,4'-dihydroxybiphenyl and 1304 parts by weight of acetic anhydride (1.1 equivalents of the total phenolic hydroxyl groups) were charged and heated to 145°C under a nitrogen gas atmosphere with stirring. After reacting for 150 minutes, the temperature was raised from 145° C. to 300° C. over 4 hours. After that, the polymerization temperature was maintained at 300° C., the pressure was reduced to 1.0 mmHg (133 Pa) over 1.0 hour, and the reaction was continued until the torque required for stirring reached 50 kg·cm to complete the polymerization. Next, the inside of the reaction vessel is pressurized to 2.0 kg/cm ² (0.20 MPa), and the polymer is discharged in strand form through a mouthpiece having a circular discharge port with a diameter of 6 mm, and pelletized by a cutter to obtain polyester. A resin (A-5) was obtained.

A composition analysis of this polyester resin (A-5) revealed that the structural unit derived from p-hydroxybenzoic acid (structural unit (II)) was 54.3 mol%, derived from 6-hydroxy-2-naphthoic acid. The structural unit (structural unit (II)) is 3.9 mol%, the structural unit (structural unit (I)) derived from 2,2-bis(4-hydroxyphenyl)hexafluoropropane is 17.1 mol%, Structural units derived from 4,4'-dihydroxybiphenyl (structural units derived from aromatic diol) accounted for 3.9 mol%, and structural units derived from terephthalic acid accounted for 20.8 mol%. Also, Tm was 267°C and Tg was 135°C.

The obtained polyester resin (A-5) pellets were pulverized by a coarse pulverizer to obtain a coarse powder having a volume average particle size of about 100 μm. 900 parts by weight of N-methylpyrrolidone was added to 100 parts by weight of the obtained powder, and the mixture was heated to 130° C. and stirred for 1 hour using a homogenizer (manufactured by IKA) to obtain a polyester resin composition. At this time, the volume average particle size of the polyester resin dispersed in the composition was 13 μm.

The obtained polyester resin composition was applied to the roughened surface of the copper foil using a film applicator and an automatic coating device (manufactured by BEVS) so that the thickness of the cast film was 400 μm, and the coating was carried out at 40° C. for 4 hours. After removing the dispersion medium by drying for a period of time, heat treatment was further performed by holding in a hot air oven at 255° C. for 6 hours under a nitrogen atmosphere to obtain a laminate of copper foil and polyester resin film.

[Example 6]
25 parts by weight of p-hydroxybenzoic acid, 1186 parts by weight of 6-hydroxy-2-naphthoic acid, and 882 parts by weight of 2,2-bis(4-carboxyphenyl)hexafluoropropane were placed in a 5 L reaction vessel equipped with a stirring blade and a distillation tube. Parts by weight, 419 parts by weight of 4,4'-dihydroxybiphenyl and 1233 parts by weight of acetic anhydride (1.1 equivalents of total phenolic hydroxyl groups) were charged, and reacted at 145°C for 150 minutes with stirring under a nitrogen gas atmosphere. , from 145° C. to 300° C. over 5.5 hours. After that, the polymerization temperature was maintained at 300° C., the pressure was reduced to 1.0 mmHg (133 Pa) over 1.0 hour, and the reaction was continued until the torque required for stirring reached 45 kg·cm to complete the polymerization. Next, the inside of the reaction vessel is pressurized to 2.0 kg/cm ² (0.20 MPa), and the polymer is discharged in strand form through a mouthpiece having a circular discharge port with a diameter of 6 mm, and pelletized by a cutter to obtain polyester. A resin (A-6) was obtained.

A composition analysis of this polyester resin (A-6) revealed that the structural unit derived from p-hydroxybenzoic acid (structural unit (II)) was 1.6 mol%, derived from 6-hydroxy-2-naphthoic acid. The structural unit (structural unit (II)) is 57.4 mol%, the structural unit (structural unit (I)) derived from 2,2-bis(4-carboxyphenyl)hexafluoropropane is 20.5 mol%, Structural units derived from 4,4'-dihydroxybiphenyl (structural units derived from aromatic diol) accounted for 20.5 mol%. Also, Tm was 271°C and Tg was 132°C.

The obtained polyester resin (A-6) pellets were pulverized by a coarse pulverizer to obtain a coarse powder having a volume average particle size of about 100 μm. 900 parts by weight of N-methylpyrrolidone was added to 100 parts by weight of the obtained powder, and the mixture was heated to 130° C. and stirred for 1 hour using a homogenizer (manufactured by IKA) to obtain a polyester resin composition. At this time, the volume average particle size of the polyester resin dispersed in the composition was 15 μm.

The obtained polyester resin composition was applied to the roughened surface of the copper foil using a film applicator and an automatic coating device (manufactured by BEVS) so that the thickness of the cast film was 400 μm, and the coating was carried out at 40° C. for 4 hours. After removing the dispersion medium by drying for a period of time, heat treatment was further performed by holding in a hot air oven at 260° C. for 6 hours under a nitrogen atmosphere to obtain a laminate of copper foil and polyester resin film.

[Comparative Example 1]
25 parts by weight of p-hydroxybenzoic acid, 1355 parts by weight of 6-hydroxy-2-naphthoic acid, 178 parts by weight of hydroquinone, 269 parts by weight of terephthalic acid and 1160 parts by weight of acetic anhydride were placed in a 5 L reactor equipped with a stirring blade and a distillation tube. (1.07 equivalents of the total phenolic hydroxyl groups) were charged and reacted at 150° C. for 120 minutes while stirring in a nitrogen gas atmosphere, and then the temperature was raised from 150° C. to 360° C. over 4 hours. Thereafter, the polymerization temperature was maintained at 360° C., the pressure was reduced to 1.0 mmHg (133 Pa) over 1.0 hour, and the reaction was continued until the torque required for stirring reached 30 kg·cm, and polymerization was completed. Next, the inside of the reaction vessel is pressurized to 2.0 kg/cm ² (0.20 MPa), and the polymer is discharged in strand form through a mouthpiece having a circular discharge port with a diameter of 6 mm, and pelletized by a cutter to obtain polyester. A resin (A-7) was obtained.

A composition analysis of this polyester resin (A-7) revealed that the structural unit derived from p-hydroxybenzoic acid (structural unit (II)) was 1.7 mol% and derived from 6-hydroxy-2-naphthoic acid. Structural unit (structural unit (II)) is 67.7 mol%, structural unit derived from hydroquinone (structural unit derived from aromatic diol) is 15.3 mol%, and structural unit derived from terephthalic acid is 15.7 mol%. It was 3 mol %. Also, Tm was 332°C and Tg was 122°C.

The obtained polyester resin (A-7) pellets were pulverized by a coarse pulverizer to obtain a coarse powder having a volume average particle size of about 100 μm. 900 parts by weight of N-methylpyrrolidone was added to 100 parts by weight of the obtained powder, and the mixture was heated to 130° C. and stirred for 1 hour using a homogenizer (manufactured by IKA) to obtain a polyester resin composition. At this time, the volume average particle size of the polyester resin dispersed in the composition was 38 μm.

The obtained polyester resin composition was applied to the roughened surface of the copper foil using a film applicator and an automatic coating device (manufactured by BEVS) so that the thickness of the cast film was 400 μm, and the coating was carried out at 40° C. for 4 hours. After removing the dispersion medium by drying for a period of time, heat treatment was further performed by holding in a hot air oven at 320° C. for 6 hours under a nitrogen atmosphere to obtain a laminate of copper foil and polyester resin film.

[Comparative Example 2]
7 parts by weight of p-hydroxybenzoic acid, 356 parts by weight of 6-hydroxy-2-naphthoic acid, and 2,2-bis(4-hydroxyphenyl)hexafluoropropane 1755 were placed in a 5 L reaction vessel equipped with a stirring blade and a distillation tube. Parts by weight, 867 parts by weight of terephthalic acid and 1353 parts by weight of acetic anhydride (1.07 equivalents of the total phenolic hydroxyl groups) were charged and reacted at 150°C for 120 minutes with stirring under a nitrogen gas atmosphere. °C over 4 hours. After that, the polymerization temperature was maintained at 300° C., the pressure was reduced to 1.0 mmHg (133 Pa) over 1.0 hour, and the reaction was continued until the torque required for stirring reached 35 kg·cm to complete the polymerization. Next, the inside of the reaction vessel is pressurized to 2.0 kg/cm ² (0.20 MPa), and the polymer is discharged in strand form through a mouthpiece having a circular discharge port with a diameter of 6 mm, and pelletized by a cutter to obtain polyester. A resin (A-8) was obtained.

A composition analysis of this polyester resin (A-8) revealed that the structural unit (structural unit (II)) derived from p-hydroxybenzoic acid was 0.4 mol% and derived from 6-hydroxy-2-naphthoic acid. The structural unit (structural unit (II)) is 15.2 mol%, the structural unit (structural unit (I)) derived from 2,2-bis(4-hydroxyphenyl)hexafluoropropane is 42.2 mol%, Structural units derived from terephthalic acid accounted for 42.2 mol %. Moreover, Tm was not observed, and Tg was 180°C.

The obtained polyester resin (A-8) pellets were pulverized by a coarse pulverizer to obtain a coarse powder having a volume average particle size of about 100 μm. 900 parts by weight of N-methylpyrrolidone was added to 100 parts by weight of the obtained powder, and the mixture was heated to 130° C. and stirred for 1 hour using a homogenizer (manufactured by IKA) to obtain a polyester resin composition. At this time, the volume average particle size of the polyester resin dispersed in the composition was 10 μm.

[Comparative Example 3]
1106 parts by weight of p-hydroxybenzoic acid, 579 parts by weight of 6-hydroxy-2-naphthoic acid and 207 parts by weight of 2,2-bis(4-hydroxyphenyl)hexafluoropropane were placed in a 5 L reaction vessel equipped with a stirring blade and a distillation tube. Parts by weight, 102 parts by weight of terephthalic acid and 1346 parts by weight of acetic anhydride (1.07 equivalents of the total phenolic hydroxyl groups) were charged and reacted at 150°C for 120 minutes with stirring under a nitrogen gas atmosphere. °C over 4 hours. After that, the polymerization temperature was kept at 300° C., the pressure was reduced to 1.0 mmHg (133 Pa) over 1.0 hour, and the reaction was continued until the torque required for stirring reached 40 kg·cm to complete the polymerization. Next, the inside of the reaction vessel is pressurized to 2.0 kg/cm ² (0.20 MPa), and the polymer is discharged in strand form through a mouthpiece having a circular discharge port with a diameter of 6 mm, and pelletized by a cutter to obtain polyester. A resin (A-9) was obtained.

A composition analysis of this polyester resin (A-9) revealed that the structural unit derived from p-hydroxybenzoic acid (structural unit (III)) was 65.0 mol%, derived from 6-hydroxy-2-naphthoic acid. The structural unit (structural unit (II)) is 25.0 mol%, the structural unit (structural unit (I)) derived from 2,2-bis(4-hydroxyphenyl)hexafluoropropane is 5.0 mol%, Structural units derived from terephthalic acid accounted for 5.0 mol %. Also, Tm was 235°C and Tg was 118°C.

The obtained polyester resin (A-9) pellets were pulverized by a coarse pulverizer to obtain a powder. The obtained powder was press molded (molding time: 5 minutes, molding pressure: 10 MPa) using a 37t manual hot press machine (Shindo Kinzoku Kogyo NF-37HH) with the mold temperature set to 260 ° C. A film of -9 and 0.08 mm thick was obtained. The resulting film was placed on a copper foil (12 μm thick) and pressed (1 MPa) at 255° C. for 15 minutes to obtain a copper-clad laminate.

Table 1 shows the results of the following evaluations (4) to (6) for the laminates obtained from the polyester resin compositions of Examples 1 to 6 and Comparative Examples 1 to 3. In addition, the content (mol%) of the structural unit (I) relative to 100 mol% of the total structural units of the <1> polyester resin obtained by the composition analysis of the polyester resins described in Examples 1 to 4 and Comparative Examples 1 to 3 ), <2> Content (mol%) of structural unit (II) with respect to 100 mol% of all structural units of polyester resin, <3> 4,4-dihydroxybiphenyl or hydroquinone with respect to 100 mol% of all structural units of polyester resin ( <4> The content (mol%) of structural units derived from aromatic diol) and the content (mol%) of structural units derived from terephthalic acid (dicarbonyl unit) relative to 100 mol% of the total structural units of the polyester resin. Table 1 also shows the measurement results of the volume average particle size of the polyester resin in the <5> polyester resin composition.

(4) Evaluation of dielectric properties at high frequency For the laminates of copper foil and polyester resin film obtained in each example and comparative example, the copper foil was removed using a ferric chloride solution, and a polyester resin film with a thickness of 20 μm was obtained. got A 10 mm square film-shaped sample for evaluation was produced from the obtained polyester resin film. Using the obtained film for dielectric property evaluation, a cut-off cylindrical waveguide method (JIS R1660-1 (2004)) is performed using a network analyzer N5227A manufactured by Keysight Technologies Inc. and SUM-CYLINDER Ver2 manufactured by Samtec Co., Ltd. The dielectric constant at 23° C. and 65 GHz was determined by The smaller the dielectric constant value, the better the dielectric properties at high frequencies.

(5) Metal adhesion The laminate of the copper foil and polyester resin film obtained in each example and comparative example was made into a strip with a width of 10 mm, and the polyester resin layer was fixed with double-sided tape. , Peel strength (kgf/cm) was measured when the copper foil was peeled off at a rate of 50 mm/min so as to be perpendicular to each resin layer. The higher the peel strength, the better the metal adhesion.

(6) Strength evaluation From the laminates of copper foil and polyester resin film obtained in each example and comparative example, the copper foil was removed using a ferric chloride solution to obtain a polyester resin film having a thickness of 20 µm. From the obtained polyester resin film, a sample was cut into a strip having a length of 150 mm and a width of 10 mm. The measurement was performed 5 times according to the method specified in JIS K 7127 (1999), and the average value of the tensile strength (MPa) was calculated. The higher the value, the better the strength.

When the polyester resin composition of the present invention is formed into a film, it has low dielectric properties at high frequencies, and is excellent in strength and metal adhesion. Films and laminates obtained from the polyester resin composition of the present invention are used for circuit boards such as flexible printed wiring boards and rigid printed wiring boards using laminates characterized by laminating a plurality of sheets, and for use in semiconductor packages. preferred.

Claims (4)

A polyester resin comprising the following structural unit (I) and structural unit (II) as essential components, wherein the content of the structural unit (I) is 1 to 40 mol% with respect to 100 mol% of the total structural units of the polyester resin A polyester resin composition comprising a resin and a medium.

(R ¹ represents one selected from a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an aryl group, and a trifluoromethyl group (CF ₃ ); Ar represents benzene, naphthalene, biphenyl, and triphenyl; represents any selected aromatic ring structure, and these aromatic rings are any substituent selected from alkyl groups having 1 to 5 carbon atoms, aryl groups, halogen atoms, and trifluoromethyl groups (CF ₃ ) X ¹ and X ² each independently represent O, CO, or NH.)
(Ar ² represents any one selected from 1,4-phenylene, 1,3-phenylene, 2,6-naphthalene and 2,7-naphthalene.) The polyester resin composition according to claim 1, wherein the structural unit (I) is a structural unit shown in (i) below.

(X ¹ and X ² each independently represent O, CO, or NH; R ¹ is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an aryl group, or a trifluoromethyl group (CF ₃ ), and R ² and R ³ each independently represent any one selected from an alkyl group having 1 to 5 carbon atoms, an aryl group, a halogen atom, and a trifluoromethyl group (CF ₃ ). , n and m each independently represent an integer of 0 to 4.) A method for producing a laminate, comprising coating the polyester resin composition according to claim 1 or 2 on a support and removing the medium to obtain a laminate. A method for producing a polyester resin film, comprising producing a laminate by the production method according to claim 3 and then removing the support.