JP2020029500A - Liquid crystal polyester resin for coverlay - Google Patents

Abstract

To provide a liquid crystal polyester resin for a coverlay capable of obtaining a film excellent in curl property and flexibility, and a coverlay comprising the same.SOLUTION: The liquid polyester resin for a coverlay contains 3-40 mol% of a structural unit derived from a 2C-4C aliphatic diol to 100 mol% of total structural units of a liquid polyester resin, has an area fraction of 10,000 or less of an absolute molecular weight of 10-40% to 100% of total peak areas of a molecular weight distribution measured by a gel permeation chromatograph/a light scattering method, and has an area fraction of 50,000 or more of an absolute molecular weight of 3-20%.SELECTED DRAWING: None

Description

  The present invention relates to a liquid crystal polyester resin for coverlay. More specifically, the present invention relates to a liquid crystal polyester resin for a coverlay capable of obtaining a film having excellent curl properties and flexibility, and a coverlay comprising the same.

  Liquid crystal polyester resin is excellent in heat resistance, fluidity and dimensional stability due to its liquid crystal structure. For this reason, demand is increasing mainly for electric and electronic parts that require these characteristics, but in particular, with the recent increase in performance of devices, the size and thickness of the above components have been reduced. Among them, flexible printed circuit boards and flexible rigid boards are extremely thin and lightweight, and can be bent freely, so that small gaps and three-dimensional arrangement of electric and electronic parts, hinges for mobile phones, arms of HDDs, etc. Thus, wiring can be performed at the movable portion that is repeatedly bent. After a conductive pattern is formed on a flexible copper-clad laminate, a flexible printed board is provided with a cover layer, a so-called coverlay, from the viewpoint of maintaining insulation, protecting wiring, heat resistance, and bending characteristics. A resin film is used for the coverlay, and the use of liquid crystal polyester resin with excellent dielectric properties is expected to expand in high-frequency applications such as mobile terminals and in-vehicle substrates, such as 5G-compatible smartphones, in the future. You.

  As an example of using a liquid crystal polyester resin for a coverlay, for example, a coverlay made of a film-like liquid crystal polyester resin has been proposed (for example, see Patent Document 1). In addition, since it is used for flexible printed wiring boards, etc., the liquid crystal polyester resin has excellent flexibility (resistance when repeatedly bending a molded product) and heat resistance as required characteristics, but has improved flexibility. As the liquid crystal polyester resin, for example, a coverlay made of a thermoplastic polymer having a multiaxial orientation or a thermoplastic liquid crystal polymer film having a melting point of 295 ° C. or more to improve heat resistance may be used. A coverlay as a material (for example, see Patent Document 3) has been proposed.

JP-A-2017-135216 JP 2012-119446 A International Publication No. WO 2014/046024

  On the other hand, a film used as a coverlay is required to have a property of not easily curling when formed into a laminate with a wiring board, and the coverlay made of a liquid crystal polyester resin described in Patent Document 1 uses a unique laminating method. However, although the curl property is improved (it is difficult to curl), the curl property is still not sufficient, and the bending property is not sufficient. Further, the cover lay made of a liquid crystal polyester resin described in Patent Literature 2 improves the flexibility but is still insufficient, and the curling property is not sufficient. Further, the cover lay made of a liquid crystal polyester resin described in Patent Document 3 has sufficient heat resistance but not sufficient curl and flexibility. Therefore, an object of the present invention is to provide a liquid crystal polyester resin for a coverlay that can solve the above-mentioned problems and obtain a film having excellent curl properties and bendability, and a coverlay made of the same.

  The present inventors have conducted intensive studies in order to solve the above-described problems, and as a result, preferably have a specific amount of aliphatic diol, and a liquid crystal polyester resin for coverlay having a specific molecular weight distribution, curl properties and bending. The present inventors have found that a coverlay having excellent properties can be obtained, and have reached the present invention.

That is, the present invention has been made to solve at least a part of the problems described above, and can be realized as the following embodiments.
(1) The area fraction with an absolute molecular weight of 10,000 or less is 10 to 40% with respect to 100% of the total peak area of the absolute molecular weight distribution measured by gel permeation chromatography / light scattering method of the liquid crystal polyester resin, and A liquid crystal polyester resin for coverlay having an area fraction of 3 to 20% having an absolute molecular weight of 50,000 or more.
(2) The cover lay resin laminate liquid crystal polyester resin has 3 to 40 mol% of structural units derived from an aliphatic diol having 2 to 4 carbon atoms, based on 100 mol% of all structural units of the liquid crystal polyester resin. A liquid crystal containing 15 to 80 mol% of a structural unit derived from an aromatic hydroxycarboxylic acid, 3 to 20 mol% of a structural unit derived from an aromatic diol, and 7 to 40 mol% of a structural unit derived from an aromatic dicarboxylic acid. The liquid crystal polyester resin for a coverlay according to (1), which is a polyester resin.
(3) A liquid crystal polyester liquid composition containing 300 to 10000 parts by weight of a solvent for dissolving the liquid crystal polyester resin with respect to 100 parts by weight of the liquid crystal polyester resin for coverlay according to (1) or (2).
(4) A liquid crystal polyester resin film comprising the liquid crystal polyester resin for coverlay described in (1) or (2) or the liquid crystal polyester liquid composition described in (3).
(5) A method for producing a liquid crystal polyester resin film, which comprises casting the liquid crystal polyester liquid composition according to (3) on a support and removing the solvent.
(6) The method for producing a liquid crystal polyester resin film according to (5), wherein a heat treatment step is performed after removing the solvent.
(7) A coverlay comprising the liquid crystal polyester resin film according to (4).

  According to the liquid crystal polyester resin for coverlay of the present invention, a film having excellent curl and flexibility can be obtained. Such a resin is suitable for a coverlay for flexible printed wiring in electric / electronic parts and mechanical parts.

  Hereinafter, the present invention will be described in detail.

<Liquid crystal polyester resin for coverlay>
The liquid crystal polyester resin for coverlay of the present invention is a polyester that forms an anisotropic molten phase. As the liquid crystal polyester resin for coverlay, for example, polyester composed of a structural unit selected from oxycarbonyl units, dioxy units, dicarbonyl units and the like to form an anisotropic molten phase, which will be described later, and the like can be mentioned.

  Next, the structural units constituting the liquid crystal polyester resin for coverlay will be described.

  Specific examples of the oxycarbonyl unit include structural units formed from aromatic hydroxycarboxylic acids such as p-hydroxybenzoic acid, m-hydroxybenzoic acid, and 6-hydroxy-2-naphthoic acid. From the viewpoint of obtaining a coverlay excellent in curl and flexibility, a structural unit generated from an aromatic hydroxycarboxylic acid is preferable, and a structural unit generated from p-hydroxybenzoic acid is particularly preferable.

  Specific examples of the dioxy unit include 4,4′-dihydroxybiphenyl, hydroquinone, resorcinol, t-butylhydroquinone, phenylhydroquinone, chlorohydroquinone, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, and 3,4′- Dihydroxybiphenyl, 2,2-bis (4-hydroxyphenyl) propane, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxydiphenylsulfone, 4,4′-dihydroxydiphenylsulfide, 4,4′-dihydroxybenzophenone, etc. Structural units formed from aromatic diols, such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, and neopentyl glycol Concrete unit, 1,4-cyclohexanediol, and structural unit derived from alicyclic diol such as 1,4-cyclohexanedimethanol. From the viewpoint of obtaining a coverlay having excellent curl and flexibility, a structural unit generated from ethylene glycol, 4,4′-dihydroxybiphenyl and hydroquinone is preferable, and a structural unit generated from ethylene glycol and 4,4′-dihydroxybiphenyl is preferable. Particularly preferred.

  Specific examples of the dicarbonyl unit 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, and 4,4'-diphenyletherdicarboxylic acid Structural units generated from aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, dodecanedioic acid and hexahydroterephthalic acid; 1,4-cyclohexanedicarboxylic acid; Examples include a structural unit formed from an alicyclic dicarboxylic acid such as cyclohexanedicarboxylic acid. From the viewpoint of obtaining a coverlay having excellent curl and flexibility, a structural unit generated from an aromatic dicarboxylic acid is preferable, and a structural unit generated from terephthalic acid or isophthalic acid is particularly preferable.

  Further, in addition to the above structural units, structural units formed from p-aminobenzoic acid, p-aminophenol, and the like may further have a range in which liquid crystallinity and characteristics are not impaired.

  The raw material monomer constituting each of the above structural units is not particularly limited as long as it is a structure capable of forming each structural unit, but an acylated product of a hydroxyl group of each structural unit, an esterified product of a carboxyl group of each structural unit, an acid halide And carboxylic acid derivatives such as acid anhydrides and the like may be used.

  The liquid crystal polyester resin for a cover lay body of the present invention exhibits aromaticity with respect to 100 mol% of all structural units of the liquid crystal polyester resin from the viewpoint of exhibiting liquid crystallinity and obtaining a cover lay having excellent curl and flexibility. It is preferable to contain 15 mol% or more of structural units derived from hydroxycarboxylic acid. It is more preferably at least 30 mol%, further preferably at least 40 mol%. On the other hand, the content is preferably not more than 80 mol% from the viewpoint of suppressing the generation of infusible material and obtaining a coverlay having excellent curl and flexibility. It is more preferably at most 75 mol%, further preferably at most 70 mol%.

  The liquid crystal polyester resin for coverlay of the present invention is, from the viewpoint of obtaining a coverlay with excellent solubility of the coverlay liquid crystal polyester resin and curling properties and flexibility when forming a liquid composition described below, from the viewpoint of obtaining a liquid crystal polyester. It is preferable that 3 mol% or more of a structural unit derived from an aliphatic diol having 2 to 4 carbon atoms is contained based on 100 mol% of all structural units of the resin. It is more preferably at least 5 mol%, further preferably at least 7 mol%. On the other hand, from the viewpoint of obtaining a coverlay having excellent curl properties and flexibility after exhibiting liquid crystallinity, the content is preferably 40 mol% or less. It is more preferably at most 35 mol%, further preferably at most 30 mol%.

  The liquid crystal polyester resin for a cover lay of the present invention has an aromatic diol based on 100 mol% of all structural units of the liquid crystal polyester resin from the viewpoint of obtaining a cover lay having excellent curl and flexibility after exhibiting liquid crystallinity. It is preferable to contain 3 mol% or more of structural units derived from It is more preferably at least 4 mol%, further preferably at least 5 mol%. On the other hand, from the viewpoint of obtaining a coverlay having excellent curl properties and flexibility, the content is preferably 20 mol% or less. It is more preferably at most 15 mol%, further preferably at most 10 mol%.

  The liquid crystal polyester resin for a cover lay of the present invention, from the viewpoint of exhibiting liquid crystallinity and obtaining a cover lay having excellent curl and flexibility, is based on aromatic dicarboxylic acid with respect to 100 mol% of all structural units of the liquid crystal polyester resin. It is preferable to contain 7 mol% or more of a structural unit derived from an acid. It is more preferably at least 10 mol%, further preferably at least 12 mol%. On the other hand, from the viewpoint of obtaining a coverlay having excellent curling and bending properties, the content is preferably 40 mol% or less. It is more preferably at most 35 mol%, further preferably at most 30 mol%.

  Further, the molecular weight distribution is controlled to a suitable range described below, from the viewpoint of obtaining a coverlay excellent in curl and flexibility, the proportion of the structural unit derived from the diol unit is based on the structural unit derived from the dicarbonyl unit. , 1.01 to 1.07.

The method for calculating the content of each structural unit for the liquid crystal polyester resin for coverlay of the present invention will be described below. First, it was weighed liquid crystal polyester resin NMR (nuclear magnetic resonance) tube, liquid crystal polyester resin is dissolved in soluble solvents (e.g., pentafluorophenol / heavy tetrachloroethane -d ₂ solvent mixture). Next, ¹ H-NMR spectrum measurement is performed on the obtained solution, and the solution can be calculated from the peak area ratio derived from each structural unit.

  The melting point (Tm) of the liquid crystal polyester resin for coverlay of the present invention is preferably 200 ° C. or higher, more preferably 250 ° C. or higher, and further preferably 300 ° C. or higher, from the viewpoint of heat resistance. On the other hand, from the viewpoint of excellent workability, the melting point (Tm) of the liquid crystal polyester resin for coverlay is preferably 360 ° C or lower, more preferably 350 ° C or lower, further preferably 340 ° C or lower.

The melting point (Tm) is measured by differential scanning calorimetry. Specifically, first, an endothermic peak temperature (Tm ₁ ) is observed by heating the polymerized polymer from room temperature under a heating condition of 20 ° C./min. After observation of an endothermic peak temperature (Tm _1), holding the polymer for 5 minutes at a temperature of the endothermic peak temperature _(Tm 1) + 20 ℃. Thereafter, the polymer is cooled to room temperature under a temperature-lowering condition of 20 ° C./min. Then, the endothermic peak temperature (Tm ₂ ) is observed by heating the polymer at a temperature rising condition of 20 ° C./min. The melting point (Tm) refers to the endothermic peak temperature (Tm ₂ ).

  The melt viscosity of the liquid crystal polyester resin for coverlay of the present invention is preferably 1 Pa · s or more, more preferably 3 Pa · s or more, and further preferably 5 Pa · s or more, from the viewpoint of obtaining a coverlay having excellent curl and flexibility. preferable. On the other hand, when a liquid composition described below is used, the melt viscosity of the liquid crystal polyester resin is 35 Pa from the viewpoint of excellent solubility of the liquid crystal polyester resin for coverlay and from the viewpoint of obtaining a coverlay with excellent curl and flexibility. S or less, preferably 20 Pa s or less, more preferably 10 Pa s or less.

  The melt viscosity is a value measured by a Koka flow tester at a temperature of the melting point (Tm) of the liquid crystal polyester resin + 10 ° C. and a shear rate of 1000 / sec.

  The liquid crystal polyester resin for a coverlay of the present invention has an area fraction of 10% to 40% with an absolute molecular weight of 10,000 or less based on 100% of the total peak area of the absolute molecular weight distribution measured by gel permeation chromatography / light scattering method. It is. If the area fraction having an absolute molecular weight of 10000 or less is less than 10%, the curl property in the case of a coverlay is significantly reduced due to a decrease in the number of terminal groups of the liquid crystal polyester resin. 12% or more is more preferable, and 13% or more is further preferable, since a coverlay excellent in curling property can be obtained. On the other hand, if the area fraction with an absolute molecular weight of 10,000 or less is larger than 40%, the coverlay becomes brittle, and the curl and the flexibility are greatly reduced. From the viewpoint of obtaining a coverlay excellent in curling and bending properties, 35% or less is more preferable, and 30% or less is still more preferable.

  Further, the liquid crystal polyester resin for coverlay of the present invention has an area fraction of 50,000 or more in absolute molecular weight of 50,000 or more with respect to 100% of the total peak area of the absolute molecular weight distribution measured by gel permeation chromatography / light scattering method. 20%. When the area fraction with an absolute molecular weight of 50,000 or more is less than 3%, the coverlay becomes brittle, and the curl and the flexibility are greatly reduced. From the viewpoint of obtaining a coverlay excellent in curling and bending properties, 5% or more is more preferable, and 7% or more is further preferable. On the other hand, if the area fraction with an absolute molecular weight of 50,000 or more is larger than 20%, the curl property in the case of a coverlay is greatly reduced due to a decrease in the number of terminal groups of the liquid crystal polyester resin, and the flexibility is particularly large. descend. 17% or less is more preferable, and 15% or less is more preferable, since a coverlay excellent in curling property can be obtained.

  The absolute number average molecular weight of the liquid crystal polyester resin for a coverlay of the present invention is preferably 3,000 or more, more preferably 5,000 or more, and still more preferably 7000 or more, from the viewpoint of obtaining a coverlay having excellent curl and flexibility. In addition, from the viewpoint of obtaining a coverlay excellent in adhesion and flexibility, 17000 or less is preferable, 15,000 or less is more preferable, and 13,000 or less is further preferable.

  The absolute weight average molecular weight of the liquid crystal polyester resin for coverlay of the present invention is preferably 10,000 or more, more preferably 13,000 or more, and still more preferably 15,000 or more, from the viewpoint of obtaining a coverlay with excellent adhesion and flexibility. In addition, from the viewpoint of obtaining a coverlay excellent in adhesion and flexibility, it is preferably 40,000 or less, more preferably 37000 or less, and still more preferably 35,000 or less.

  The polydispersity, which is a value obtained by dividing the absolute weight average molecular weight of the liquid crystal polyester resin for coverlay of the present invention by the absolute number average molecular weight, is 2.2 or more from the viewpoint of obtaining a coverlay having excellent curl and flexibility. Is preferably 2.3 or more, more preferably 2.4 or more. In addition, from the viewpoint of obtaining a coverlay excellent in curling and bending properties, it is preferably 3.5 or less, more preferably 3.3 or less, and still more preferably 3.0 or less.

  The absolute molecular weight can be measured by a GPC / light scattering method (gel permeation chromatography / light scattering method) using a solvent in which a liquid crystal polyester resin is soluble as an eluent. Examples of the solvent in which the liquid crystal polyester is soluble include halogenated phenols and a mixed solvent of a halogenated phenol and a general organic solvent. Preference is given to pentafluorophenol and a mixed solvent of pentafluorophenol and chloroform. Among them, a mixed solvent of pentafluorophenol / chloroform is particularly preferred from the viewpoint of handling properties.

  The following methods (A) to (C) can be used to control the area fraction of the liquid crystal polyester resin for coverlay of the present invention having an absolute molecular weight of 10,000 or less or 50,000 or more within the above-mentioned preferred range. .

  (A) A method in which the acetylation reaction time at an internal temperature of 140 ° C. to 145 ° C. is 40 to 100 minutes in the acetylation reaction of a phenolic hydroxyl group when producing a liquid crystal polyester resin for coverlay.

  (B) A method in which the amount of acetic anhydride is adjusted to 1.00 to 1.08 molar equivalents of the total of phenolic hydroxyl groups of the liquid crystal polyester resin material for cover lay when producing the cover lay liquid crystal polyester resin.

  (C) A method in which the ratio of the structural unit derived from the diol unit of the liquid crystal polyester resin for coverlay is set to 1.01 to 1.07 with respect to the structural unit derived from the dicarbonyl unit.

  By the above method, the molecular weight distribution can be controlled by controlling the polymerization rate, and the area fraction with an absolute molecular weight of 10,000 or less or 50,000 or more can be controlled in the above-mentioned preferred range. Among them, the method (A) is preferred.

<Production method of liquid crystal polyester resin for coverlay>
The method for producing the liquid crystal polyester resin for coverlay used in the present invention is not particularly limited, and it can be produced according to a known polyester polycondensation method. Known polyester polycondensation methods include structural units derived from p-hydroxybenzoic acid, structural units derived from 4,4′-dihydroxybiphenyl, structural units derived from terephthalic acid, and structural units derived from ethylene glycol. The following may be mentioned as an example of a liquid crystal polyester resin for a coverlay laminate composed of:

  (1) p-acetoxybenzoic acid, 4,4′-diacetoxybiphenyl and terephthalic acid, and a polymer or oligomer of polyethylene terephthalate, or bis (β-β) of an aromatic dicarboxylic acid such as bis (β-hydroxyethyl) terephthalate A method for producing a liquid crystal polyester resin from a (hydroxyethyl) ester by a deacetic acid polycondensation reaction.

  (2) Polymers, oligomers of polyesters such as p-hydroxybenzoic acid, 4,4'-dihydroxybiphenyl, terephthalic acid and polyethylene terephthalate or bis (β-hydroxyethyl) terephthalate and aromatic dicarboxylic acids such as bis ( A method of producing a liquid crystal polyester resin by reacting (β-hydroxyethyl) ester with acetic anhydride to acetylate a phenolic hydroxyl group and then subjecting it to deacetic acid polycondensation reaction.

  (3) A method in which 1,2-bis (4-hydroxybenzoyl) ethane is used as a part of the starting material in the production method of (1) or (2) as disclosed in JP-A-3-59024.

  Above all, the method (2) is preferably used because it is industrially excellent in controlling the degree of polymerization of the liquid crystal polyester resin for coverlay.

  In the case of the production by the method (2), it is easy to control the molecular weight distribution of the liquid crystal polyester resin for cover lay within the above-mentioned preferred range, and from the viewpoint of obtaining a cover lay excellent in curl and flexibility, anhydrous The amount of acetic acid is preferably from 1.00 to 1.08 molar equivalents, more preferably from 1.02 to 1.08 molar equivalents, based on the total of the phenolic hydroxyl groups of the liquid crystal polyester resin raw material for coverlay.

  Further, in the acetylation reaction of the phenolic hydroxyl group, the molecular weight distribution is controlled by controlling the polymerization rate to such an extent that the polymerization rate is not excessively slowed down, and the area fraction of the absolute molecular weight of 10,000 or less or 50,000 or more is controlled in the above preferred range. From the viewpoint, the acetylation reaction time at an internal temperature of 140 to 145 ° C is preferably set to 40 minutes or more. The time is more preferably 45 minutes or more, and further preferably 50 minutes or more. On the other hand, from the viewpoint of controlling the molecular weight distribution by controlling the polymerization rate to such an extent that the polymerization rate does not become excessively high, and controlling the area fraction of the absolute molecular weight of 10000 or less or 50,000 or more to the above-mentioned preferable range, It is preferred that the acetylation reaction time at a temperature of from ℃ to 145 ℃ be 110 minutes or less. The time is more preferably 100 minutes or less, and further preferably 90 minutes or less. Since the temperature at which the acetylation reaction proceeds efficiently is 140 ° C. or more at the internal temperature, and the temperature at which acetic acid as a by-product starts to be distilled is 145 ° C., the acetylation at the internal temperature of 140 to 145 ° C. We focused on the chemical reaction.

  As a method for producing the liquid crystal polyester resin used in the present invention, the polycondensation reaction can be completed by a solid phase polymerization method. Examples of the treatment by the solid phase polymerization method include the following methods. First, a polymer or oligomer of a liquid crystal polyester resin is pulverized by a pulverizer. The reaction is completed by heating the pulverized polymer or oligomer under a nitrogen stream or under reduced pressure to polycondensate to a desired degree of polymerization. The heating can be performed in the range of the melting point of the liquid crystal polyester of -50 ° C to -5 ° C (eg, 200 to 300 ° C) for 1 to 50 hours.

  Although the polycondensation reaction of the liquid crystal polyester resin proceeds without a catalyst, stannous acetate, tetrabutyl titanate, potassium acetate and sodium acetate, antimony trioxide, metal magnesium and the like can be used as a catalyst.

<Liquid crystal polyester resin liquid composition>
The liquid crystal polyester resin for coverlay of the present invention can be used in various applications as a liquid composition dissolved in a solvent, because of its excellent solubility in a solvent. A method for producing such a liquid composition will be described. The solvent used in the production of the liquid composition is not particularly limited as long as it can dissolve the liquid crystal polyester resin, and examples thereof include a halogenated phenol, a halogenated alcohol, and a mixed solvent of the above solvent and a general organic solvent. Can be Examples of the halogenated phenol include 2-chlorophenol, 3-chlorophenol, 4-chlorophenol, 2,4,6-trichlorophenol, 2-fluorophenol, 3-fluorophenol, 4-fluorophenol, 2,4,6 -Trifluorophenol, pentafluorophenol and the like, and the halogenated alcohols include hexafluoroisopropanol. It is preferable that pentafluorophenol is contained most in view of solubility.

  The liquid crystal polyester resin liquid composition of the present invention is controlled so that the solution viscosity is not too high, can be uniformly applied when coated on a support or the like, and is excellent in curl and flexibility when used as a coverlay. From the viewpoint, the solvent is preferably 300 parts by weight or more based on 100 parts by weight of the liquid crystal polyester resin for coverlay. More preferably, it is 400 parts by weight or more, and still more preferably 500 parts by weight or more. On the other hand, by ensuring the solution viscosity, it is possible to apply evenly when applying to a support or the like, and from the viewpoint of excellent curl and flexibility when used as a coverlay, 100 parts by weight of a liquid crystal polyester resin for coverlay The solvent is preferably 10,000 parts by weight or less. It is more preferably at most 5,000 parts by weight, further preferably at most 2,000 parts by weight.

  If necessary, the liquid composition may be filtered through a filter or the like to remove fine foreign substances contained in the liquid composition.

<Filling material>
Known fillers, additives, and the like may be added to the liquid crystal polyester resin for coverlay or the liquid crystal polyester resin liquid composition of the present invention as long as the effects of the present invention are not impaired.

  Examples of the filler include fibrous, whisker-like, plate-like, powder-like, and granular fillers. Specifically, as the fibrous or whisker-like filler, glass fiber, PAN-based or pitch-based carbon fiber, stainless fiber, metal fiber such as aluminum fiber or brass fiber, aromatic polyamide fiber or liquid crystal polyester fiber, etc. Organic fiber, gypsum fiber, ceramic fiber, asbestos fiber, zirconia fiber, alumina fiber, silica fiber, titanium oxide fiber, silicon carbide fiber, rock wool, potassium titanate whisker, barium titanate whisker, aluminum borate whisker, silicon nitride whisker And acicular titanium oxide. Examples of the plate-like filler include mica, talc, kaolin, glass flake, clay, molybdenum disulfide, and wollastenite. Examples of the powdery or granular filler include silica, glass beads, titanium oxide, zinc oxide, calcium polyphosphate, and graphite. The surface of the filler used in the present invention may be treated with a known coupling agent (for example, a silane coupling agent, a titanate coupling agent, or the like), or another surface treatment agent. Further, two or more fillers may be used in combination.

  Examples of the additives include an antioxidant, a heat stabilizer (for example, hindered phenol, hydroquinone, phosphite, thioethers and the like), an ultraviolet absorber (for example, resorcinol, salicylate), phosphorous acid Colorants including coloring agents such as salts and hypophosphites, lubricants and release agents (montanic acid and its metal salts, its esters, its half esters, stearyl alcohol, stearamide and polyethylene wax, etc.), dyes or pigments From carbon black, crystal nucleating agents, plasticizers, flame retardants (bromine-based flame retardants, phosphorus-based flame retardants, red phosphorus, silicone-based flame retardants, etc.), flame-retardant auxiliary agents, and antistatic agents The usual additives selected can be incorporated.

<Liquid crystal polyester resin film and coverlay>
The liquid crystal polyester resin for a coverlay or the liquid crystal polyester resin liquid composition of the present invention can be used as a raw material for producing a liquid crystal polyester resin film or a coverlay. The liquid crystal polyester resin film and the cover lay can be produced, for example, by the following methods (I) and (II).

  (I) A method in which the liquid crystalline polyester resin for coverlay of the present invention is melt-extruded by, for example, a single-screw extruder, a twin-screw extruder, a vent extruder, a tandem extruder or the like to form a film.

  (II) A method of casting the liquid crystal polyester resin liquid composition of the present invention on a support such as a protective sheet, removing the solvent, and subsequently peeling the liquid from the support to obtain a film.

  From the viewpoint of reducing the anisotropy peculiar to the liquid crystal polyester resin and excellent in the curlability and flexibility of the cover lay, and from the viewpoint that the liquid crystal polyester resin film of the present invention can be obtained by a simple operation, the method (II) is preferred. preferable.

The support used in the production method of the present invention is not particularly limited, and is selected from metals, glasses, polymers, and the like. It is important that the support has resistance to the solvent used. The support may be a simple substance such as metal, glass, or polymer, or may be a composite material.

  Hereinafter, a method of manufacturing a coverlay by the method (II) will be described.

  Examples of the method of applying the liquid crystal polyester resin liquid composition to the support include various methods such as a roller coating method, a dip coating method, a spray coater method, a spinner coating method, a curtain coating method, a slot coating method, and a screen printing method. By these means, the coating liquid is cast flat and uniformly by these means to form a coating film.

  Subsequently, the solvent in the coating film is removed, and a liquid crystal polyester resin layer is formed on the surface of the support. The method for removing the solvent is preferably performed by evaporating the solvent. Examples of the method for evaporating the solvent include methods such as heating, decompression, and ventilation.

  Further, heat treatment may be performed if necessary. The heat treatment method is not particularly limited, and the heat treatment can be performed using a device such as a hot air oven, a reduced pressure oven, or a hot plate. The heat treatment may be performed under atmospheric pressure or under pressure or reduced pressure as long as the copper foil and the liquid crystal polyester resin are not deteriorated. Further, from the viewpoint of suppressing the deterioration of the liquid crystal polyester resin, it is preferable to perform the heat treatment in an inert gas atmosphere. For example, the temperature is raised from the melting point of the liquid crystal polyester resin for coverlay −50 ° C. to the melting point −5 ° C. to the range of the melting point + 5 ° C. to the melting point + 50 ° C. over 1 to 50 hours under a nitrogen stream. Can be.

  The cover lay can be affixed to each support by the following methods (III) and (IV), for example, to form a laminate having the cover lay.

  (III) A method in which the coverlay produced by the method of (I) or (II) is attached to an insulating layer having a conductive wiring on the insulating layer by heat compression to form a laminate.

  (IV) A method in which the coverlay manufactured by the method of (I) or (II) is attached to an insulating layer having conductive wiring on the insulating layer with an adhesive or an adhesive sheet to form a laminate.

  (V) A glass cloth base epoxy resin laminate (FR-4 or FR-5) or a glass composite base epoxy on which a coverlay manufactured by the method of (I) or (II) is mounted with conductive wiring or the like. A method of attaching a resin laminate (such as CEM-3) to form a laminate.

  The insulating layer is not particularly limited as long as it has an insulating property. Examples of commonly used insulating layers include a polyimide film, a liquid crystal polyester film, and a cycloolefin polymer film.

  As a structure of a laminate having a coverlay obtained in this way, for example, a three-layer structure in which a coverlay is laminated on a layer made of a film and a layer made of wiring, and further alternatively, a film and a wiring layer are alternately formed For example, a multilayer structure of four or more layers laminated may be mentioned.

  The coverlay obtained by the above method can easily obtain a coverlay having a uniform thickness, a high curling property with an insulating layer and wiring, and an excellent flexibility, so that electric / electronic parts and mechanical parts can be obtained. It is suitably used for flexible printed wiring boards, rigid printed wiring boards, and the like.

<Example>
Hereinafter, the present invention will be described using examples, but the present invention is not limited to the examples. In the examples, the composition and property evaluation of the liquid crystal polyester resin were measured by the following methods.

(1) Composition Analysis of Liquid Crystal Polyester Resin The composition analysis of the liquid crystal polyester resin was performed by ¹ H-nuclear magnetic resonance spectrum ( ¹ H-NMR) measurement. 50 mg of the liquid crystal polyester resin is weighed in an NMR sample tube, dissolved in 800 μL of a solvent (a mixed solvent of pentafluorophenol / 1,1,2,2-tetrachloroethane-d ₂ = 65/35 (weight ratio)), and UNITY INOVA500 ¹ H-NMR measurement was performed at an observation frequency of 500 MHz and a temperature of 80 ° C. using an NMR spectrometer (manufactured by Varian), and the composition was determined from the peak area ratio derived from each structural unit observed around 7 to 9.5 ppm. analyzed.

(2) Measurement of Absolute Molecular Weight of Liquid Crystal Polyester Resin The absolute molecular weight distribution of the liquid crystal polyester resin was measured by gel permeation chromatography (GPC) / LALLS method under the following conditions, and the absolute number average molecular weight, absolute weight average molecular weight, and absolute molecular weight were measured. The area fraction of 10,000 or less and the area fraction of 50,000 or more in absolute molecular weight were determined.

(GPC)
GPC device: made by Waters
Detector: Differential refractive index detector RI2410 (Waters)
Column: Shodex K-806M (2), K-802 (1) (Showa Denko)
Eluent: pentafluorophenol / chloroform (35/65 w / w%)
Measurement temperature: 23 ° C
Flow rate: 0.8 mL / min
Sample injection volume: 200 μL (concentration: 0.1%).

(LALLS)
Apparatus: Low angle laser light scattering photometer KMX-6 (manufactured by Chromatix)
Detector wavelength: 633 nm (He-Ne)
Detector temperature: 23 ° C.

(3) Melting point (Tm) of liquid crystal polyester resin
After observing the endothermic peak temperature (Tm ₁ ) observed when the temperature of the liquid crystal polyester resin is increased from room temperature by 20 ° C./min with a differential scanning calorimeter DSC-7 (manufactured by PerkinElmer), Tm _{1 is} measured. After holding at a temperature of + 20 ° C. for 5 minutes, the sample was once cooled to room temperature under a temperature-lowering condition of 20 ° C./min, and then an endothermic peak temperature (Tm ₂ ) observed when the temperature was raised again at a temperature rising condition of 20 ° C./min. Was taken as the melting point. In the following production examples, the melting point (Tm ₂ ) is described as Tm.

(4) Melt viscosity of liquid crystal polyester resin Melting of liquid crystal polyester resin using a Koka type flow tester CFT-500D (orifice 0.5φ × 10 mm) (manufactured by Shimadzu Corporation) under conditions of Tm + 10 ° C. and shear rate 1000 / s. The viscosity was measured.

[Example 1]
In a 5 L reaction vessel equipped with a stirring blade and a distillation tube, 994 parts by weight of p-hydroxybenzoic acid, 126 parts by weight of 4,4'-dihydroxybiphenyl, 112 parts by weight of terephthalic acid, and an intrinsic viscosity of about 0.6 dl / g. 216 parts by weight of polyethylene terephthalate and 960 parts by weight of acetic anhydride (1.10 equivalents of the total of phenolic hydroxyl groups) were charged and reacted at 145 ° C. for 80 minutes while stirring under a nitrogen gas atmosphere. The temperature was raised over time. At this time, the reaction time at an internal temperature of 140 to 145 ° C was 75 minutes. Thereafter, the polymerization temperature was maintained at 320 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) in 1.0 hour, the reaction was continued for further 20 minutes, and the polymerization was completed when the torque required for stirring reached 20 kg · cm. . Next, the inside of the reaction vessel was pressurized to 1.0 kg / cm ² (0.1 MPa), and the polymer was discharged into a strand through a die having one circular discharge port with a diameter of 10 mm, and pelletized by a cutter. A liquid crystal polyester resin (A-1) was obtained.

  The composition of this liquid crystal polyester resin (A-1) was analyzed. As a result, the structural unit derived from p-hydroxybenzoic acid was 66.7 mol%, and the structural unit derived from 4,4′-dihydroxybiphenyl was 6.3. Mol%, the structural unit derived from terephthalic acid was 16.7 mol%, and the structural unit derived from ethylene glycol was 10.4 mol%. Further, Tm was 313 ° C., melt viscosity was 13 Pa · s, absolute number average molecular weight was 10,000, and absolute weight average molecular weight was 26,000.

[Example 2]
In a 5 L reaction vessel equipped with a stirring blade and a distillation tube, 994 parts by weight of p-hydroxybenzoic acid, 126 parts by weight of 4,4'-dihydroxybiphenyl, 112 parts by weight of terephthalic acid, and an intrinsic viscosity of about 0.6 dl / g. 216 parts by weight of polyethylene terephthalate and 943 parts by weight of acetic anhydride (1.08 equivalents of the total of phenolic hydroxyl groups) were charged and reacted at 145 ° C. for 80 minutes while stirring under a nitrogen gas atmosphere. The temperature was raised over time. At this time, the reaction time at an internal temperature of 140 to 145 ° C was 75 minutes. Thereafter, the polymerization temperature was maintained at 320 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) in 1.0 hour, the reaction was continued for further 30 minutes, and the polymerization was completed when the torque required for stirring reached 20 kg · cm. . Next, the inside of the reaction vessel was pressurized to 1.0 kg / cm ² (0.1 MPa), and the polymer was discharged into a strand through a die having one circular discharge port with a diameter of 10 mm, and pelletized by a cutter. A liquid crystal polyester resin (A-2) was obtained.

  Composition analysis of this liquid crystal polyester resin (A-2) revealed that the structural unit derived from p-hydroxybenzoic acid was 66.7 mol%, and the structural unit derived from 4,4′-dihydroxybiphenyl was 6.3. Mol%, the structural unit derived from terephthalic acid was 16.7 mol%, and the structural unit derived from ethylene glycol was 10.4 mol%. Further, Tm was 313 ° C., melt viscosity was 13 Pa · s, absolute number average molecular weight was 9,500, and absolute weight average molecular weight was 26500.

[Example 3]
In a 5 L reaction vessel equipped with a stirring blade and a distilling tube, 994 parts by weight of p-hydroxybenzoic acid, 134 parts by weight of 4,4'-dihydroxybiphenyl, 112 parts by weight of terephthalic acid, and an intrinsic viscosity of about 0.6 dl / g. 216 parts by weight of polyethylene terephthalate and 960 parts by weight of acetic anhydride (1.10 equivalents of the total of phenolic hydroxyl groups) were charged and reacted at 145 ° C. for 80 minutes while stirring under a nitrogen gas atmosphere. The temperature was raised over time. At this time, the reaction time at an internal temperature of 140 to 145 ° C was 75 minutes. Thereafter, the polymerization temperature was maintained at 320 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) in 1.0 hour, the reaction was continued for further 30 minutes, and the polymerization was completed when the torque required for stirring reached 20 kg · cm. . Next, the inside of the reaction vessel was pressurized to 1.0 kg / cm ² (0.1 MPa), and the polymer was discharged into a strand through a die having one circular discharge port with a diameter of 10 mm, and pelletized by a cutter. A liquid crystal polyester resin (A-3) was obtained.

  The composition of this liquid crystal polyester resin (A-3) was analyzed. As a result, the structural unit derived from p-hydroxybenzoic acid was 66.4 mol%, and the structural unit derived from 4,4′-dihydroxybiphenyl was 6.6. Mol%, the structural unit derived from terephthalic acid was 16.6 mol%, and the structural unit derived from ethylene glycol was 10.4 mol%. Further, Tm was 313 ° C., melt viscosity was 13 Pa · s, absolute number average molecular weight was 9,500, and absolute weight average molecular weight was 26500.

[Example 4]
976 parts by weight of p-hydroxybenzoic acid, 126 parts by weight of 4,4'-dihydroxybiphenyl, 112 parts by weight of terephthalic acid, and an intrinsic viscosity of about 0.6 dl / g were placed in a 5 L reaction vessel equipped with a stirring blade and a distilling tube. 242 parts by weight of polyethylene terephthalate and 945 parts by weight of acetic anhydride (1.10 equivalents of the total of phenolic hydroxyl groups) were charged and reacted at 145 ° C. for 75 minutes while stirring under a nitrogen gas atmosphere. The temperature was raised over time. At this time, the reaction time at an internal temperature of 140 to 145 ° C was 70 minutes. Thereafter, the polymerization temperature was maintained at 310 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) in 1.0 hour, the reaction was continued for further 20 minutes, and the polymerization was completed when the torque required for stirring reached 20 kg · cm. . Next, the inside of the reaction vessel was pressurized to 1.0 kg / cm ² (0.1 MPa), and the polymer was discharged into a strand through a die having one circular discharge port with a diameter of 10 mm, and pelletized by a cutter. A liquid crystal polyester resin (A-4) was obtained.

  The composition of this liquid crystal polyester resin (A-4) was analyzed. As a result, the structural unit derived from p-hydroxybenzoic acid was 64.6 mol%, and the structural unit derived from 4,4′-dihydroxybiphenyl was 6.2. Mol%, the structural unit derived from terephthalic acid was 17.7 mol%, and the structural unit derived from ethylene glycol was 11.5 mol%. Further, Tm was 300 ° C., melt viscosity was 13 Pa · s, absolute number average molecular weight was 10,000, and absolute weight average molecular weight was 25500.

[Example 5]
In a 5 L reaction vessel equipped with a stirring blade and a distilling tube, 901 parts by weight of p-hydroxybenzoic acid, 126 parts by weight of 4,4'-dihydroxybiphenyl, 112 parts by weight of terephthalic acid, and an intrinsic viscosity of about 0.6 dl / g. 346 parts by weight of polyethylene terephthalate and 884 parts by weight of acetic anhydride (1.10 equivalents of the total of phenolic hydroxyl groups) were charged and reacted at 145 ° C. for 85 minutes while stirring under a nitrogen gas atmosphere. The temperature was raised over time. At this time, the reaction time at an internal temperature of 140 to 145 ° C was 80 minutes. Thereafter, the polymerization temperature was maintained at 290 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) in 1.0 hour, the reaction was continued for another 20 minutes, and the polymerization was completed when the torque required for stirring reached 20 kg · cm. . Next, the inside of the reaction vessel was pressurized to 1.0 kg / cm ² (0.1 MPa), and the polymer was discharged into a strand through a die having one circular discharge port with a diameter of 10 mm, and pelletized by a cutter. A liquid crystal polyester resin (A-5) was obtained.

  The composition of this liquid crystal polyester resin (A-5) was analyzed. As a result, the structural unit derived from p-hydroxybenzoic acid was 56.9 mol%, and the structural unit derived from 4,4′-dihydroxybiphenyl was 5.9. Mol%, the structural unit derived from terephthalic acid was 21.6 mol%, and the structural unit derived from ethylene glycol was 15.7 mol%. Further, Tm was 263 ° C., melt viscosity was 13 Pa · s, absolute number average molecular weight was 10,500, and absolute weight average molecular weight was 25,000.

[Example 6]
A 5 L reaction vessel equipped with a stirring blade and a distilling tube was charged with 528 parts by weight of p-hydroxybenzoic acid, 126 parts by weight of 4,4'-dihydroxybiphenyl, 112 parts by weight of terephthalic acid, and an intrinsic viscosity of about 0.6 dl / g. 865 parts by weight of polyethylene terephthalate and 581 parts by weight of acetic anhydride (1.10 equivalents of phenolic hydroxyl groups in total) were charged and reacted at 145 ° C. for 90 minutes while stirring under a nitrogen gas atmosphere. The temperature was raised over time. At this time, the reaction time at an internal temperature of 140 to 145 ° C was 85 minutes. Thereafter, the polymerization temperature was maintained at 290 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) in 1.0 hour, the reaction was continued for 30 minutes, and the polymerization was completed when the torque required for stirring reached 20 kg · cm. . Next, the inside of the reaction vessel was pressurized to 1.0 kg / cm ² (0.1 MPa), and the polymer was discharged into a strand through a die having one circular discharge port with a diameter of 10 mm, and pelletized by a cutter. A liquid crystal polyester resin (A-6) was obtained.

  The composition of this liquid crystal polyester resin (A-6) was analyzed. As a result, the structural unit derived from p-hydroxybenzoic acid was 27.0 mol%, and the structural unit derived from 4,4′-dihydroxybiphenyl was 4.8. Mol%, the structural unit derived from terephthalic acid was 36.5 mol%, and the structural unit derived from ethylene glycol was 31.7 mol%. Further, Tm was 210 ° C., melt viscosity was 50 Pa · s, absolute number average molecular weight was 12,800, and absolute weight average molecular weight was 36,000.

[Example 7]
In a 5 L reaction vessel equipped with a stirring blade and a distillation tube, 994 parts by weight of p-hydroxybenzoic acid, 126 parts by weight of 4,4'-dihydroxybiphenyl, 112 parts by weight of terephthalic acid, and an intrinsic viscosity of about 0.6 dl / g. 216 parts by weight of polyethylene terephthalate and 960 parts by weight of acetic anhydride (1.10 equivalents of the total of phenolic hydroxyl groups) were charged and reacted at 145 ° C. for 110 minutes while stirring under a nitrogen gas atmosphere. The temperature was raised over time. At this time, the reaction time at an internal temperature of 140 to 145 ° C was 105 minutes. Thereafter, the polymerization temperature was maintained at 320 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) in 1.0 hour, the reaction was continued for further 10 minutes, and the polymerization was completed when the torque required for stirring reached 20 kg · cm. . Next, the inside of the reaction vessel was pressurized to 1.0 kg / cm ² (0.1 MPa), and the polymer was discharged into a strand through a die having one circular discharge port with a diameter of 10 mm, and pelletized by a cutter. A liquid crystal polyester resin (A-7) was obtained.

  The composition of this liquid crystal polyester resin (A-7) was analyzed. As a result, the structural unit derived from p-hydroxybenzoic acid was 66.7 mol%, and the structural unit derived from 4,4′-dihydroxybiphenyl was 6.3. Mol%, the structural unit derived from terephthalic acid was 16.7 mol%, and the structural unit derived from ethylene glycol was 10.4 mol%. Further, Tm was 313 ° C., melt viscosity was 13 Pa · s, absolute number average molecular weight was 11,000, and absolute weight average molecular weight was 25200.

Example 8
In a 5 L reaction vessel equipped with a stirring blade and a distillation tube, 994 parts by weight of p-hydroxybenzoic acid, 126 parts by weight of 4,4'-dihydroxybiphenyl, 112 parts by weight of terephthalic acid, and an intrinsic viscosity of about 0.6 dl / g. 216 parts by weight of polyethylene terephthalate and 960 parts by weight of acetic anhydride (1.10 equivalents of phenolic hydroxyl groups in total) were charged and reacted at 145 ° C. for 50 minutes while stirring under a nitrogen gas atmosphere. The temperature was raised over time. At this time, the reaction time at an internal temperature of 140 to 145 ° C was 43 minutes. Thereafter, the polymerization temperature was maintained at 320 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) in 1.0 hour, the reaction was continued for further 60 minutes, and the polymerization was completed when the torque required for stirring reached 20 kg · cm. . Next, the inside of the reaction vessel was pressurized to 1.0 kg / cm ² (0.1 MPa), and the polymer was discharged into a strand through a die having one circular discharge port with a diameter of 10 mm, and pelletized by a cutter. A liquid crystal polyester resin (A-8) was obtained.

  Composition analysis of this liquid crystal polyester resin (A-8) revealed that the structural unit derived from p-hydroxybenzoic acid was 66.7 mol%, and the structural unit derived from 4,4′-dihydroxybiphenyl was 6.3. Mol%, the structural unit derived from terephthalic acid was 16.7 mol%, and the structural unit derived from ethylene glycol was 10.4 mol%. Further, Tm was 313 ° C., melt viscosity was 13 Pa · s, absolute number average molecular weight was 8,200, and absolute weight average molecular weight was 25,500.

[Example 9]
In a 5 L reaction vessel equipped with a stirring blade and a distillation tube, 994 parts by weight of p-hydroxybenzoic acid, 126 parts by weight of 4,4'-dihydroxybiphenyl, 112 parts by weight of terephthalic acid, and an intrinsic viscosity of about 0.6 dl / g. 216 parts by weight of polyethylene terephthalate and 960 parts by weight of acetic anhydride (1.10 equivalents of the total of phenolic hydroxyl groups) were charged and reacted at 145 ° C. for 80 minutes while stirring under a nitrogen gas atmosphere. The temperature was raised over time. At this time, the reaction time at an internal temperature of 140 to 145 ° C was 43 minutes. Thereafter, the polymerization temperature was maintained at 320 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) in 1.0 hour, the reaction was continued for further 10 minutes, and the polymerization was completed when the torque required for stirring reached 10 kg · cm. . Next, the inside of the reaction vessel was pressurized to 1.0 kg / cm ² (0.1 MPa), and the polymer was discharged into a strand through a die having one circular discharge port with a diameter of 10 mm, and pelletized by a cutter. A liquid crystal polyester resin (A-9) was obtained.

  A composition analysis of this liquid crystal polyester resin (A-9) revealed that the structural unit derived from p-hydroxybenzoic acid was 66.7 mol%, and the structural unit derived from 4,4′-dihydroxybiphenyl was 6.3. Mol%, the structural unit derived from terephthalic acid was 16.7 mol%, and the structural unit derived from ethylene glycol was 10.4 mol%. Further, Tm was 310 ° C., melt viscosity was 3 Pa · s, absolute number average molecular weight was 5,500, and absolute weight average molecular weight was 16,000.

[Example 10]
In a 5 L reaction vessel equipped with a stirring blade and a distilling tube, 994 parts by weight of p-hydroxybenzoic acid, 126 parts by weight of 4,4'-dihydroxybiphenyl, 112 parts by weight of isophthalic acid, and an intrinsic viscosity of about 0.6 dl / g. 216 parts by weight of polyethylene terephthalate and 960 parts by weight of acetic anhydride (1.10 equivalents of the total of phenolic hydroxyl groups) were charged and reacted at 145 ° C. for 80 minutes while stirring under a nitrogen gas atmosphere. The temperature was raised over time. At this time, the reaction time at an internal temperature of 140 to 145 ° C was 75 minutes. Thereafter, the polymerization temperature was maintained at 320 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) in 1.0 hour, the reaction was continued for further 20 minutes, and the polymerization was completed when the torque required for stirring reached 20 kg · cm. . Next, the inside of the reaction vessel was pressurized to 1.0 kg / cm ² (0.1 MPa), and the polymer was discharged into a strand through a die having one circular discharge port with a diameter of 10 mm, and pelletized by a cutter. A liquid crystal polyester resin (A-10) was obtained.

  The composition of this liquid crystal polyester resin (A-10) was analyzed. As a result, the structural unit derived from p-hydroxybenzoic acid was 66.7 mol%, and the structural unit derived from 4,4′-dihydroxybiphenyl was 6.3. Mol%, the structural unit derived from isophthalic acid was 16.7 mol%, and the structural unit derived from ethylene glycol was 10.4 mol%. Further, Tm was 305 ° C., melt viscosity was 13 Pa · s, absolute number average molecular weight was 9,500, and absolute weight average molecular weight was 26,000.

[Example 11]
870 parts by weight of p-hydroxybenzoic acid, 352 parts by weight of 4,4'-dihydroxybiphenyl, 89 parts by weight of hydroquinone, 292 parts by weight of terephthalic acid, 157 parts by weight of isophthalic acid And 314 parts by weight of acetic anhydride (1.10 equivalents of the total of phenolic hydroxyl groups) were charged and reacted at 145 ° C. for 90 minutes while stirring under a nitrogen gas atmosphere, and then the temperature was raised from 145 ° C. to 330 ° C. in 4 hours. I let it. At this time, the reaction time at an internal temperature of 140 to 145 ° C was 85 minutes. Thereafter, the polymerization temperature was maintained at 330 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) in 1.0 hour, the reaction was continued for further 10 minutes, and the polycondensation was completed when the torque reached 10 kg · cm. Next, the inside of the reaction vessel was pressurized to 1.0 kg / cm ² (0.1 MPa), and the polymer was discharged into a strand through a die having one circular discharge port with a diameter of 10 mm, and pelletized by a cutter. A liquid crystal polyester resin (A-11) was obtained.

  The composition of this liquid crystal polyester resin (A-11) was analyzed. As a result, the structural unit derived from p-hydroxybenzoic acid was 53.8 mol%, and the structural unit derived from 4,4′-dihydroxybiphenyl was 16.2. Mol%, the structural unit derived from hydroquinone was 6.9%, the structural unit derived from terephthalic acid was 15.0 mol%, and the structural unit derived from isophthalic acid was 8.1 mol%. Further, Tm was 310 ° C., melt viscosity was 13 Pa · s, absolute number average molecular weight was 9,500, and absolute weight average molecular weight was 21,000.

[Comparative Example 1]
In a 5 L reaction vessel equipped with a stirring blade and a distillation tube, 994 parts by weight of p-hydroxybenzoic acid, 126 parts by weight of 4,4'-dihydroxybiphenyl, 112 parts by weight of terephthalic acid, and an intrinsic viscosity of about 0.6 dl / g. 216 parts by weight of polyethylene terephthalate and 960 parts by weight of acetic anhydride (1.10 equivalents of the total of phenolic hydroxyl groups) were charged and reacted at 145 ° C. for 120 minutes while stirring under a nitrogen gas atmosphere. The temperature was raised over time. At this time, the reaction time at an internal temperature of 140 to 145 ° C was 115 minutes. Thereafter, the polymerization temperature was maintained at 320 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) in 1.0 hour, the reaction was continued for further 2 minutes, and the polymerization was completed when the torque required for stirring reached 20 kg · cm. . Next, the inside of the reaction vessel was pressurized to 1.0 kg / cm ² (0.1 MPa), and the polymer was discharged into a strand through a die having one circular discharge port with a diameter of 10 mm, and pelletized by a cutter. A liquid crystal polyester resin (A-12) was obtained.

  Composition analysis of this liquid crystal polyester resin (A-12) revealed that the structural unit derived from p-hydroxybenzoic acid was 66.7 mol%, and the structural unit derived from 4,4′-dihydroxybiphenyl was 6.3. Mol%, the structural unit derived from terephthalic acid was 16.7 mol%, and the structural unit derived from ethylene glycol was 10.4 mol%. Further, Tm was 313 ° C., melt viscosity was 13 Pa · s, absolute number average molecular weight was 12,500, and absolute weight average molecular weight was 25500.

[Comparative Example 2]
In a 5 L reaction vessel equipped with a stirring blade and a distillation tube, 994 parts by weight of p-hydroxybenzoic acid, 126 parts by weight of 4,4'-dihydroxybiphenyl, 112 parts by weight of terephthalic acid, and an intrinsic viscosity of about 0.6 dl / g. 216 parts by weight of polyethylene terephthalate and 960 parts by weight of acetic anhydride (1.10 equivalents of the total of phenolic hydroxyl groups) were charged and reacted at 145 ° C. for 120 minutes while stirring under a nitrogen gas atmosphere. The temperature was raised over time. At this time, the reaction time at an internal temperature of 140 to 145 ° C was 115 minutes. Thereafter, the polymerization temperature was maintained at 320 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) in 1.0 hour, the reaction was continued for further 15 minutes, and the polymerization was completed when the torque required for stirring reached 40 kg · cm. . Next, the inside of the reaction vessel was pressurized to 1.0 kg / cm ² (0.1 MPa), and the polymer was discharged into a strand through a die having one circular discharge port with a diameter of 10 mm, and pelletized by a cutter. A liquid crystal polyester resin (A-13) was obtained.

  The composition of this liquid crystal polyester resin (A-13) was analyzed. As a result, the structural unit derived from p-hydroxybenzoic acid was 66.7 mol%, and the structural unit derived from 4,4′-dihydroxybiphenyl was 6.3. Mol%, the structural unit derived from terephthalic acid was 16.7 mol%, and the structural unit derived from ethylene glycol was 10.4 mol%. Further, Tm was 313 ° C., melt viscosity was 40 Pa · s, absolute number average molecular weight was 19200, and absolute weight average molecular weight was 38500.

[Comparative Example 3]
870 parts by weight of p-hydroxybenzoic acid, 352 parts by weight of 4,4'-dihydroxybiphenyl, 89 parts by weight of hydroquinone, 292 parts by weight of terephthalic acid, 157 parts by weight of isophthalic acid And 1,314 parts by weight of acetic anhydride (1.10 equivalents of the total of phenolic hydroxyl groups), and the mixture was reacted at 145 ° C. for 120 minutes while stirring under a nitrogen gas atmosphere, and then heated from 145 ° C. to 330 ° C. in 4 hours. I let it. At this time, the reaction time at an internal temperature of 140 to 145 ° C was 115 minutes. Thereafter, while maintaining the polymerization temperature at 330 ° C. and attempting to reduce the pressure to 1.0 mmHg (133 Pa) in 1.0 hour, the torque reached 10 kg · cm before reaching 1.0 mmHg, and the polycondensation occurred. Was completed. Next, the inside of the reaction vessel was pressurized to 1.0 kg / cm ² (0.1 MPa), and the polymer was discharged into a strand through a die having one circular discharge port with a diameter of 10 mm, and pelletized by a cutter. A liquid crystal polyester resin (A-13) was obtained.

  The composition of this liquid crystal polyester resin (A-13) was analyzed. As a result, the structural unit derived from p-hydroxybenzoic acid was 53.8 mol%, and the structural unit derived from 4,4′-dihydroxybiphenyl was 16.2. Mol%, the structural unit derived from hydroquinone was 6.9%, the structural unit derived from terephthalic acid was 15.0 mol%, and the structural unit derived from isophthalic acid was 8.1 mol%. Further, Tm was 310 ° C., melt viscosity was 13 Pa · s, absolute number average molecular weight was 11,500, and absolute weight average molecular weight was 21,500.

[Comparative Example 4]
In a 5 L reaction vessel equipped with a stirring blade and a distilling tube, 218 parts by weight of p-hydroxybenzoic acid, 126 parts by weight of 4,4'-dihydroxybiphenyl, 112 parts by weight of terephthalic acid and an intrinsic viscosity of about 0.6 dl / g 1297 parts by weight of polyethylene terephthalate and 328 parts by weight of acetic anhydride (1.10 equivalents of the total of phenolic hydroxyl groups) were charged and reacted at 145 ° C. for 80 minutes while stirring under a nitrogen gas atmosphere. The temperature was raised over time. At this time, the reaction time at an internal temperature of 140 to 145 ° C was 75 minutes. Thereafter, the polymerization temperature was maintained at 290 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) in 1.0 hour, the reaction was continued for further 60 minutes, and the polymerization was completed when the torque required for stirring reached 20 kg · cm. . Next, the inside of the reaction vessel was pressurized to 1.0 kg / cm ² (0.1 MPa), and the polymer was discharged into a strand through a die having one circular discharge port with a diameter of 10 mm, and pelletized by a cutter. Polyester resin (A-14) was obtained, but no liquid crystallinity was observed.

  When a compositional analysis was performed on this polyester resin (A-14), the structural unit derived from p-hydroxybenzoic acid was 9.6 mol%, and the structural unit derived from 4,4′-dihydroxybiphenyl was 4.1 mol. %, The structural unit derived from terephthalic acid was 45.2 mol%, and the structural unit derived from ethylene glycol was 41.1 mol%. The Tm was 205 ° C., the melt viscosity was 50 Pa · s, the absolute number average molecular weight was 12,500, and the absolute weight average molecular weight was 38500.

  Subsequently, the curl and the flexibility were measured by the following methods.

(5) Flexibility The obtained liquid crystal polyester resins (A-1) to (A-14) and polyester resin (A-15) were pulverized with a coarse pulverizer into powder, and the obtained powder was 100 parts by weight. On the other hand, (A-11), (A-13) and (A-14) were added with 2,000 parts by weight of pentafluorophenol, and 1300 parts by weight with others. After heating to 130 ° C. to completely dissolve each liquid crystal polyester resin or polyester resin, the mixture was stirred and defoamed to obtain brown transparent solutions (liquid crystal polyester liquid composition and liquid ester liquid composition). The resulting solution was cast on a protective sheet, heated to 80 ° C. on a hot plate to remove the solvent, and then heat-treated at the melting point of each liquid crystal polyester resin or polyester resin at −10 ° C. for 1 hour. Was peeled off to produce a liquid crystal polyester film or polyester film of 85 μm. Then, a polyimide film having conductive wiring (“Kapton” 50EN, 12.5 μm, manufactured by Du Pont-Toray Co., Ltd.) and an adhesive layer (“Nikaflex SAFW”, 20 μm, manufactured by Nickan Industry Co., Ltd.) are overlaid. At 150 ° C. for 5 minutes (10 kg / cm 2) to obtain a laminate having a coverlay (film thickness: 100 μm). Subsequently, a laminate having the obtained coverlay was cut out to have a width of 50 mm and a length of 80 mm. For 50 of them, from the place where the length became half, bending to 180 ° and returning to the original position (0 °) were repeated, and after bending 50 times, it was immersed in red ink, washed with water and dried. The samples were subjected to a penetration deep flaw method for checking for cracks with a stereomicroscope, and the average number of inks that had permeated out of the liquid crystal polyester layer, which was the coverlay portion, was examined. It was evaluated that the smaller the number of leached inks, the better the flexibility.

(6) Curling properties The liquid crystal polyester liquid composition and the liquid ester liquid composition obtained in (5) were cast on a protective sheet, and heated to 80 ° C. on a hot plate to remove the solvent. Heat treatment was performed for 1 hour at a melting point of the resin or polyester resin of −10 ° C., and the protective sheet was peeled off to produce an 85 μm liquid crystal polyester film or polyester film. Then, a polyimide film having conductive wiring (“Kapton” 50EN, 12.5 μm, manufactured by Du Pont-Toray Co., Ltd.) and an adhesive layer (“Nikaflex SAFW”, 20 μm, manufactured by Nickan Industry Co., Ltd.) are overlaid. At 150 ° C. for 5 minutes (10 kg / cm 2) to obtain a laminate having a coverlay (film thickness: 100 μm). A laminate having a coverlay was cut out to have a width of 40 mm and a length of 40 mm. Ten of them were treated for 1 hour at the melting point of the liquid crystal polyester film or polyester film used at 10 ° C. for the laminate. After standing at room temperature for 1 hour, the laminate was placed on a surface plate such that the top was convex, and the maximum average height of the convex portions was defined as the amount of curl deformation and measured. It was evaluated that the smaller the amount of curl deformation, the better the curl property. In addition, when it deform | transformed and was on a cylinder, it was set as "deformation measurement impossible."

  From the results shown in Table 1, the liquid crystal polyester resin for coverlay of the present invention is excellent in curl and flexibility when used as a coverlay, and therefore is used for flexible printed wiring boards in electric / electronic parts and mechanical parts. It can be said that it is suitable for use in a coverlay that is used.

  The liquid crystal polyester resin for coverlay of the present invention is excellent in curl property and flexibility when used as a coverlay, so that it is suitable for use in coverlay used for flexible printed wiring boards in electric / electronic parts and mechanical parts. It is suitable.

Claims (7)

With respect to the total peak area of 100% of the molecular weight distribution of the absolute molecular weight measured by gel permeation chromatography / light scattering method of the liquid crystal polyester resin, the area fraction having an absolute molecular weight of 10,000 or less is 10 to 40%, and the absolute molecular weight is 50,000. A liquid crystal polyester resin for coverlay having the above area fraction of 3 to 20%. The cover lay resin laminate liquid crystal polyester resin has 3 to 40 mol% of a structural unit derived from an aliphatic diol having 2 to 4 carbon atoms, based on 100 mol% of all structural units of the liquid crystal polyester resin, and aromatic hydroxy. A liquid crystal polyester resin containing 15 to 80 mol% of a structural unit derived from a carboxylic acid, 3 to 20 mol% of a structural unit derived from an aromatic diol, and 7 to 40 mol% of a structural unit derived from an aromatic dicarboxylic acid. The liquid crystal polyester resin for a cover lay according to claim 1. A liquid crystal polyester liquid composition comprising 300 to 10000 parts by weight of a solvent for dissolving the liquid crystal polyester resin per 100 parts by weight of the liquid crystal polyester resin for coverlay according to claim 1. A liquid crystal polyester resin film comprising the liquid crystal polyester resin for a cover lay according to claim 1 or 2 or the liquid crystal polyester liquid composition according to claim 3. A method for producing a liquid crystal polyester resin film, comprising: casting the liquid crystal polyester liquid composition according to claim 3 on a support; and removing the solvent. The method for producing a liquid crystal polyester resin film according to claim 5, wherein a heat treatment step is performed after removing the solvent. A coverlay comprising the liquid crystal polyester resin film according to claim 4.