JP5361338B2 - adhesive - Google Patents

Description

  The present invention relates to a polyester resin composition, and more particularly to a polyester resin composition that can be used as an adhesive for wiring materials such as electrical appliances and automobile-related products.

  Polyester resins represented by polyethylene terephthalate and polybutylene terephthalate are widely used in various fields as fibers, films, molding materials, etc., taking advantage of their excellent mechanical strength, thermal stability, hydrophobicity, and chemical resistance. Yes.

  Moreover, the polyester resin can obtain the copolyester resin which has various characteristics by changing the kind of the dicarboxylic acid and glycol which are the structural components. For this reason, it is widely used for adhesives, coating agents, ink binders, paints and the like. Such a copolyester resin generally has excellent adhesion to plastics such as polyester, polycarbonate, and polyvinyl chloride resin, or metal foils such as aluminum and copper. Furthermore, it has characteristics such as electrical insulation, flame retardancy, and flexibility (peeling resistance at bent portions).

  Utilizing these characteristics, polyester adhesives are widely used for flexible flat cables that can be used as wiring materials for digital home appliances or automobiles, for example.

  As a flexible flat cable, an insulation film having two layers of a base material layer and an adhesive layer is used, the adhesive sides of the two insulation films face each other, and a conductive wire is sandwiched between them. A bonded structure can be given. As a base material layer of the insulation film, one using polyethylene terephthalate is common. For the adhesive layer, an adhesive made of a polyester resin composition having high adhesiveness is suitably used.

  In order to impart adhesiveness to the adhesive layer, it is generally mentioned that a material having a glass transition point lower than room temperature is used as the polyester resin composition. However, a material having a glass transition point lower than room temperature can impart adhesiveness as described above, but under circumstances where heat is heated up to a temperature higher than room temperature depending on the use conditions, As a negative effect due to the low, there is a risk that the adhesive layer of the flexible flat cable is tacky, blocking, flowing, and possibly causing dielectric breakdown or conductor short circuit.

  In particular, as home appliances become thinner and smaller as in recent years, the influence from various heat sources such as heat radiation from the backlight of the liquid crystal and heat radiation from the CPU cannot be ignored. For this reason, the adhesive layer is required to have the above-mentioned performance against blocking and anti-flow properties, that is, anti-blocking properties against blocking and heat resistance against anti-flow properties. ing.

In order to improve the anti-blocking property and heat resistance, a method of making the molecule difficult to move by adding a curing agent to the resin constituting the adhesive layer to form a crosslinked structure is generally used. However, when a curing agent is used, there is a problem that handling properties and adhesiveness are likely to deteriorate. Alternatively, it has been proposed to blend a polyester resin having a high glass transition point with a polyester resin having a low glass transition point (Patent Document 1). However, in this case as well, there was no problem when the demand for heat resistance was not so great because it was not thinned and miniaturized in the past, but it does not satisfy the high demand performance related to recent heat resistance as described above. Absent.
JP 2008-019375 A

  The present invention contains a polyester resin having a low glass transition point and a polyester resin having a high glass transition point, is excellent in adhesion to metals such as copper and aluminum, and has a heat resistance of UL 60 ° C. or higher. With regard to polyester resin compositions that can be used as adhesives suitable for flexible flat cables, the anti-blocking property and heat resistance have been dramatically improved without impairing the adhesive properties of the polyester resin with the lower glass transition point, which is the main component. The purpose is to be able to improve.

As a result of various studies to solve the above problems, the present inventor has reached the present invention. That is, the gist of the present invention is as follows.
(1) An organic solvent and a polyester resin composition dissolved in the organic solvent so as to have a solid content concentration of 30% by mass,
The polyester resin composition has a polyester resin (A) having an acid value of 2.0 to 30 mgKOH / g and a glass transition point of 30 ° C. or less, and a polyester resin having an acid value of 2.0 to 30 mgKOH / g and a glass transition point of 50 ° C. or more ( B) and the polyester resin (B) contains at least one of terephthalic acid and isophthalic acid as an acid component and 1 to 70 mol% of a polyhydric alcohol having a bisphenol skeleton as an alcohol component The compounding ratio of the resin (A) and the resin (B) is (A) / (B) = 90 / 10-50 / 50 (mass ratio),
Adhesive, wherein the organic solvent is a mixed solvent solution of 8/2 (weight ratio) of toluene / methyl ethyl ketone.

(2) Polyester resin (B) is an all-alcohol component of polyester resin (B) containing an aliphatic polyhydric alcohol in which one or more hydrocarbons having 1 or more carbon atoms are bonded to one monomer molecule in the side chain. hand, characterized by 1 to 70 mol% including that adhesive (1).

( 3 ) A laminate having a resin layer formed using the adhesive according to (1) or (2) and containing two or more resin layers.

  The polyester resin composition of the present invention can be used as an adhesive having excellent antiblocking properties and heat resistance while maintaining excellent adhesion to metals such as copper and aluminum, and in particular, It can be suitably used for a heat-resistant polyester-based flexible flat cable having a UL60 ° C rating or higher.

Hereinafter, the present invention will be described in detail.
The polyester resin (A) used in the present invention is required to have a glass transition point of 30 ° C. or lower, preferably 20 ° C. or lower, and more preferably 10 ° C. or lower. When the glass transition point exceeds 30 ° C., the adhesive strength to the conductor decreases. The lower limit of the glass transition point is not particularly defined, but is preferably −40 ° C. or higher, more preferably −30 ° C. or higher, and further preferably −20 ° C. or higher. When the glass transition point is lower than −40 ° C., the resin has strong adhesiveness and is difficult to handle.

  The polyester resin (A) may be crystalline or amorphous as long as it dissolves in a general-purpose organic solvent at a solid concentration of 10% by mass or more. Here, the general-purpose organic solvent means a non-halogen or non-ether solvent, for example, an aromatic solvent such as toluene, xylene, solvent naphtha, or solvesso; a ketone such as methyl ethyl ketone, methyl isobutyl ketone, or cyclohexanone. Solvents such as methyl alcohol, ethyl alcohol, isopropyl alcohol and isobutyl alcohol; ester solvents such as ethyl acetate and normal butyl acetate; acetate solvents such as cellosolve acetate and methoxyacetate; or two or more of these solvents Refers to a mixture. However, it is not limited to the individual compounds exemplified above.

  The polyester resin (A) preferably has a softening point of 55 ° C or higher. The softening point is more preferably 65 ° C. or higher, further preferably 75 ° C. or higher, and most preferably 85 ° C. or higher. If the softening point is less than 55 ° C, it is difficult to obtain the required heat resistance. If the heat resistance is low, when used in a flexible flat cable, the resin starts to move in an environment where it is exposed to high temperatures, which may cause the conductor to peel off and cause dielectric breakdown.

  The acid value of the polyester resin (A) is preferably 2.0 to 30 mgKOH / g from the viewpoint of maintaining the conductor adhesiveness, and the conductor adhesiveness decreases even if it is less than 2.0 mgKOH / g or exceeds 30 mgKOH / g. Sometimes.

  In addition, from the viewpoint of improving the solubility and adhesiveness of the polyester resin composition, the polyester resin (A) is an aliphatic polyvalent compound in which one or more hydrocarbons having 1 or more carbon atoms are bonded to one monomer molecule in the side chain. Alcohol may be contained. The content is preferably in the range of 1 to 70 mol%, more preferably 10 to 65 mol%, and even more preferably 30 to 60 mol% with respect to the alcohol component. .

  Examples of the aliphatic polyhydric alcohol in which one or more hydrocarbons having one or more carbon atoms are bonded to one monomer molecule in the side chain include propylene glycol, 2-methyl-1,3-propanediol, and 2,2-dimethyl- 1,3-propanediol, 2-ethyl-2-normalbutyl-propanediol, 3-methyl-pentanediol, polypropylene glycol and the like can be preferably used.

  The polyester resin (B) used in the present invention needs to have a glass transition point of 50 ° C. or higher. The glass transition point is preferably 55 ° C. or higher, more preferably 60 ° C. or higher, further preferably 65 ° C. or higher, and most preferably 70 ° C. or higher. When the glass transition point is less than 50 ° C., the antiblocking property is lowered. Then, when the polyester resin composition of the present invention is used as an adhesive and the insulation film obtained by coating the base film with a mixture of a filler such as a pigment and the adhesive is wound and stored, blocking occurs. Very likely.

  The mixing ratio of the polyester resin (A) and the polyester resin (B) is a mass ratio, and it is necessary that (A) / (B) = 90 / 10-50 / 50 (mass ratio). It is preferably ~ 60/40. When (A) / (B) is in the range of 90/10 to 100/0 (but not including 90/10), the antiblocking property as an adhesive is lowered, and the polyester resin composition of the present invention is bonded. As an agent, when an insulation film obtained by coating a base film with a mixture of a filler such as a pigment and the adhesive is wound up and stored, the possibility of blocking is extremely high. Moreover, heat resistance is also insufficient. On the other hand, when (A) / (B) is in the range of 50/50 to 0/100 (however, 50/50 is not included), there is an inconvenience that the adhesion to the conductor is lowered.

  The polyester resin (B) needs to contain at least one of terephthalic acid and isophthalic acid as an acid component. It is preferable to contain terephthalic acid, and it is more preferable to contain both. If neither of them is contained, the glass transition point and the softening point are lowered, the heat resistance is lowered and the antiblocking property is lowered. The content of terephthalic acid is preferably 20 mol% or more, more preferably 40 mol% or more, and still more preferably 60 mol% or more with respect to the acid component in terms of adhesive strength. The content of isophthalic acid is preferably less than 80 mol%, more preferably less than 60 mol%, and even more preferably less than 40 mol% with respect to the acid component in terms of antiblocking properties. .

  The polyester resin (B) needs to contain 1 to 70 mol% of a polyhydric alcohol having a bisphenol skeleton in the alcohol component. The content is preferably 5 to 60 mol%, more preferably 10 to 50 mol%, and most preferably 15 to 40 mol%. When the content of the polyhydric alcohol having a bisphenol skeleton is less than 1 mol%, antiblocking properties and heat resistance are lowered. On the other hand, when the content exceeds 70 mol%, when the polyester resin composition of the present invention is dissolved in an organic solvent, the polyester resin (A) and the polyester (B) are easily phase-separated into two layers. The dispersibility of the solution decreases, the average particle size becomes large, and both the conductor adhesiveness and the antiblocking property decrease.

  Examples of the polyhydric alcohol having a bisphenol skeleton include a polyalkylene oxide addition polymer of bisphenol A, a polyalkylene oxide addition polymer of bisphenol F, a polyalkylene oxide addition polymer of bisphenol S, a polyalkylene oxide addition polymer of bisphenol C, Examples thereof include a polyalkylene oxide addition polymer of bisphenol E, a polyalkylene oxide addition polymer of bisphenol P-AP, and a polyalkylene oxide addition polymer of bisphenol Z. Among these, a propylene oxide addition polymer of bisphenol A, an ethylene oxide addition polymer of bisphenol S, an ethylene oxide addition polymer of bisphenol A, and a propylene oxide addition polymer of bisphenol A are preferably used. The number of additions is preferably 2 to 100, more preferably 2 to 60, still more preferably 2 to 30, and most preferably 2 to 10 per mole of the bisphenol skeleton. When the addition number exceeds 100, the glass transition point is lowered and the antiblocking property is lowered, which is not preferable.

  The reason for using a polyhydric alcohol having a bisphenol skeleton is to increase the glass transition point and softening point of the resin, thereby imparting anti-blocking properties and heat resistance. In addition, when using a polyhydric alcohol having a bisphenol skeleton, the polyester resin (B) becomes incompatible with the polyester resin (A) when the polyester resin of the present invention is dissolved in a general-purpose organic solvent. There is a tendency to form an incompatible system in the solution and to become a turbid dispersion like fine particles. In this case, even if the solution is uniformly compatibilized and becomes a transparent solution, the required performance is exhibited. However, if the solution is in a finely dispersed state without being compatibilized, the polyester resin (A) and the polyester resin ( Since each characteristic of B) is not averaged and weakened, it can be expected to exhibit both performances of adhesiveness and antiblocking property.

  The smaller the particle size of the dispersion in the above dispersion, the better. When the polyester resin composition of the present invention is dissolved in, for example, a mixed solvent of toluene / methyl ethyl ketone 8/2 (mass ratio) so as to have a solid content concentration of 30% by mass, the median diameter of the particles of the dispersion is It is preferable that it is 500 micrometers or less. It is more preferably 300 μm or less, further preferably 200 μm or less, and most preferably 150 μm or less. When the median diameter of the particles is increased, the anti-blocking property and adhesiveness of the polyester resin composition of the present invention are lowered, or when dissolved in a general-purpose organic solvent, the two layers are easily separated and are difficult to handle. There is no particular lower limit for the median diameter of the particles. When particles are not present or are dilute, a transparent liquid with high transmittance in appearance. In that case, although it is difficult to measure the average particle size in the first place, the conductor adhesiveness and anti-blocking property tend to be lowered by averaging the characteristics as described above.

  The particle size distribution does not matter if there is more than one peak, even if it is a single peak or a double peak, but the peak top of the peak with the largest grain size is preferably less than 500 μm, more preferably less than 300 μm. , More preferably less than 200 μm, and most preferably less than 150 μm.

  As a method for reducing the average particle size of the dispersion, the acid value of the polyester (B) is set within a specific range, a polyhydric alcohol having a bisphenol skeleton or a hydrocarbon having 1 or more carbon atoms in the side chain is monomer 1 It is effective to introduce an aliphatic polyhydric alcohol bonded to one or more molecules into the polyester resin (B) at a certain ratio.

  If they are not applied, the polyester resin (A) and the polyester resin (B) are blended and dissolved in a general-purpose organic solvent. The particles that have gathered gradually grow and grow, and the micelles of the polyester resin (B) having a high specific gravity gradually settle and phase separation occurs. In that case, it is difficult to handle because it is necessary to use it at a stage before phase separation immediately after dissolution or while stirring so that bubbles do not enter. In addition, the particles tend to be large without phase separation, and the desired performance is often not obtained as described above. Therefore, it is important to prevent the finely dispersed particles from becoming large by the above-mentioned formulation.

  The acid value of the polyester resin (B) is preferably 2.0 to 30 mgKOH / g, more preferably 2.5 to 25 mgKOH / g, and still more preferably 3.0 to 20 mgKOH / g. 3.5 to 15 mgKOH / g is more preferable, and 4.0 to 10 mgKOH / g is most preferable. When the acid value is less than 2.0 mgKOH / g, the average particle diameter of the solution obtained by dissolving the polyester resin mixture of the present invention in a general-purpose organic solvent becomes large, and the liquid is separated into two layers. It is not preferable because both properties are lowered. On the other hand, when the acid value exceeds 30 mgKOH / g, the conductor adhesiveness decreases, which is not preferable.

  The aliphatic polyhydric alcohol in which one or more hydrocarbons having 1 or more carbon atoms per side chain are bonded to one monomer molecule contributes to reducing the average particle diameter of the particles as described above. It is preferable that the polyester resin (B) contains this also in the point which improves the adhesiveness to the conductor when using a resin composition as an adhesive agent. The content thereof is preferably in the range of 1 to 70 mol%, more preferably in the range of 10 to 65 mol%, still more preferably in the range of 30 to 60 mol% with respect to the alcohol component. . In the polyester resin (B), when the aliphatic polyhydric alcohol in which one or more hydrocarbons having 1 or more carbon atoms are bonded to one monomer molecule in the side chain exceeds 70 mol%, the polyester resin (A) and the polyester resin There is a tendency that the compatibility with (B) becomes excessive and the conductor adhesiveness is lowered.

  Examples of the aliphatic polyhydric alcohol in which one or more hydrocarbons having 1 or more carbon atoms are bonded to one monomer molecule in the side chain include propylene glycol, 2-methyl-1,3-propanediol, 2,2-dimethyl- 1,3-propanediol, 2-ethyl-2-normalbutyl-propanediol, 3-methyl-pentanediol, polypropylene glycol and the like are preferably used.

  The softening point of the polyester resin (B) is preferably 100 ° C. or higher, and more preferably 110 ° C. or higher. When the softening point is less than 100 ° C., the anti-blocking property or heat resistance is lowered.

  As the monomer constituting the polyester resin (B) of the present invention, examples of the acid component include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecane. Diacid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, heptadecanedioic acid, octadecanedioic acid, nonadecanedioic acid, eicosandioic acid, docosandioic acid, phthalic acid, naphthalenedicarboxylic acid, 4, 4 ' -Dicarboxybiphenyl, 5-sodium sulfoisophthalic acid, 5-hydroxy-isophthalic acid, fumaric acid, maleic acid, itaconic acid, mesaconic acid, citraconic acid, 1,3,4-benzenetricarboxylic acid, 1,2,4 5-benzenetetracarboxylic acid, pyromellitic acid, trimellitic acid, shu 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 2,5-norbornene dicarboxylic acid, dimer acid, hydrogenated dimer acid and other polyvalent carboxylic acids or anhydrides thereof May be used as necessary. However, the acid component is not limited to the above.

  Examples of the alcohol component that can be used in addition to the polyhydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polytetramethylene glycol, 1,4-butanediol, 1,5-pentanediol, , 6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 1,4-cyclohexanedimethanol, , 3-cyclohexanedimethanol, tricyclodecane dimethanol, spiroglycol, dimer diol and the like. Among these, ethylene glycol, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, tricyclodecane dimethanol and spiroglycol can be preferably used.

  Examples of hydroxycarboxylic acids include tetrahydrophthalic acid, lactic acid, oxirane, glycolic acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxyisobutyric acid, 2-hydroxy-2-methylbutyric acid, 2 Hydroxycarboxylic acids such as -hydroxyvaleric acid, 3-hydroxyvaleric acid, 4-hydroxyvaleric acid, 5-hydroxyvaleric acid, 6-hydroxycaproic acid, 10-hydroxystearic acid, 4- (β-hydroxy) ethoxybenzoic acid , And aliphatic lactones such as β-propiolactone, β-butyrolactone, γ-butyrolactone, δ-valerolactone, and ε-caprolactone may be used as necessary.

The above monomers are not necessarily used alone, and may be used in combination of two or more kinds depending on the properties to be imparted to the resin.
The polyester resin (B) may be copolymerized with a monocarboxylic acid or a monoalcohol. Examples of monocarboxylic acids include lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, benzoic acid, p-tert-butylbenzoic acid, cyclohexane acid, 4-hydroxyphenyl stearic acid, and the like. It is done. Examples of the monoalcohol include octyl alcohol, decyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, 2-phenoxyethanol and the like.

  Furthermore, in the polyester resin composition of the present invention, if necessary, heat stabilizers such as phosphoric acid and phosphoric acid esters; antioxidants such as hindered phenol compounds, hindered amine compounds and thioether compounds; talc and silica, etc. Conventional additives such as pigments such as titanium oxide, fillers, antistatic agents, and foaming agents may be included.

  The number average molecular weight of the polyester resin (A) is preferably 10,000 to 100,000, more preferably 15,000 to 60,000, and further preferably 20,000 to 40,000. When the number average molecular weight is lower than 10,000, the cohesive force is lowered and the adhesive force to the conductor is easily lowered. When the number average molecular weight is higher than 100,000, the solvent solubility is easily lowered. On the other hand, the number average molecular weight of the polyester resin (B) is preferably 4000 to 20000, more preferably 5000 to 16000, still more preferably 6000 to 12000, and more preferably 7000 to 10,000. Most preferred. If the molecular weight is too low, the cohesive force is lowered and the adhesive force to the conductor is likely to be lowered, and if the molecular weight is too high, the solution is thickened and the surface smoothness of the coating film is liable to be lowered.

The manufacturing method of a polyester resin (B) is demonstrated.
The polyester resin (B) can be produced by charging the necessary raw materials into the reaction vessel, performing an esterification reaction at a temperature of 180 ° C. or higher for 4 hours or more, and then performing polycondensation by a known method. For example, a copolyester resin can be obtained by advancing the polycondensation reaction at a temperature of 220 to 280 ° C. under a reduced pressure of 130 Pa or less until a desired molecular weight is reached.

In the esterification reaction and polycondensation reaction, titanium compounds such as tetrabutyl titanate; metal acetates such as zinc acetate, magnesium acetate, and zinc acetate; antimony trioxide; hydroxybutyltin oxide, tin octylate, etc. These organotin compounds can be used as a catalyst. In this case, the amount of catalyst used is preferably 0.1 to 20 × 10 ⁻⁴ with respect to 1 mol of the acid component.

  In addition, after completion of the above polycondensation reaction, a predetermined amount of a polybasic acid component or an anhydride thereof is added and reacted to modify the terminal hydroxyl group to a carboxyl group or to a carboxyl group in the molecular chain by transesterification. Or the like, it is possible to impart an appropriate acid value.

  The polyester resin (A) can also be obtained by a similar method.

  According to the present invention, a predetermined amount of the polyester resin (A) and the polyester resin (B) are blended and not particularly limited. For example, the polyester resin (A) and the polyester resin (B) are soluble from the aforementioned non-ether-based and non-halogen-based general-purpose organic solvents. A solvent can be selected to make the solution. The solid concentration at that time is preferably 20 to 50% by mass.

  Moreover, it is preferable that it is 10-40 mass% of the whole resin concentration, and it is more preferable that it is 20-30 mass%.

  The solution viscosity is preferably 5000 mPa · s or less, more preferably 4000 mPa · s or less, even more preferably 3000 mPa · s or less, and 2000 mPa · s or less when measured at 25 ° C. with a B-type viscometer. Most preferably, it is s or less. When it exceeds 5000 mPa · s, it is necessary to use it in a heated state, which may cause problems in handling.

  A flame retardant can be added to the polyester resin composition of the present invention as necessary. Examples of the flame retardant include halides such as decabromodiphenyl ether, bis (pentabromophenyl) ethane, tetrabromobisphenol, hexabromocyclododecane, hexabromobenzene; triphenyl phosphate, tricresyl phosphate, 1,3-phenylene Phosphorus compounds such as bis (diphenyl phosphate), ammonium polyphosphate, polyphosphate amide, and guanidine phosphate; halogen-containing phosphate esters such as tris (chloroethyl) phosphate and tris (dichloropropyl) phosphate; red phosphorus; triazine, melamine isocyanurate, ethylene Nitrogen flame retardants such as dimelamine; inorganic flame retardant aids such as tin dioxide, antimony pentoxide, antimony trioxide, aluminum hydroxide, magnesium hydroxide; silicone powder, etc.In order to reduce the environmental load, it is preferable to select a flame retardant from the viewpoints of non-halogen, non-phosphorus, and demetalized metal. However, the flame retardant is not limited to the above.

  The polyester resin composition of the present invention includes, as necessary, epoxy resin, acid anhydride, hexamethylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, xylylene diisocyanate, dicyclohexylmethane diisocyanate and the like. Isocyanates and blocked isocyanates thereof; curing agents such as uretdiones and β-hydroxyalkylamides; curing catalysts such as triethylenediamine and triethylamine; pigments such as titanium dioxide, calcium carbonate and zinc oxide; talc; polyethylene wax; paraffin wax; Fire etc. can be used.

  As described above, the polyester resin composition of the present invention can be made into a solvent-type adhesive, but the base material film is coated with the solvent-type adhesive by a known coating method and dried to obtain a laminate. be able to. Examples of the coater that can be used include a bar coater, a comma coater, a die coater, a roll coater, a reverse roll coater, a gravure coater, a gravure reverse coater, and a flow coater. In the coating method using these coaters, the thickness of the adhesive layer can be arbitrarily controlled. Moreover, you may laminate | stack adhesive resin by multiple times of coating.

A flexible flat cable can be manufactured as follows, for example.
That is, an adhesive containing the polyester resin composition of the present invention is applied to a base film having a thickness of about 10 to 200 μm formed of polyester such as polyethylene terephthalate so as to have a dry thickness of about 2 to 100 μm. The film is dried at 80 to 150 ° C. to produce an insulation film. Then, a conductor such as tin-plated copper having a thickness of about 20 to 100 μm is sandwiched between the surfaces of the adhesive layers of the two insulation films, and a heat sealer is used at a temperature of about 150 to 180 ° C. for 0.2 to A flexible flat cable can be manufactured by processing at a pressure of 0.8 MPa for about 1 to 20 seconds.

  If necessary, a primer layer may be provided on the insulation film.

Next, the present invention will be specifically described by way of examples. In addition, the various physical-property values in a following example, a reference example, and a comparative example were measured with the following method.
(1) Number average molecular weight of polyester resin It was determined by GPC analysis. Specifically, a liquid feeding unit LC-10ADvp type manufactured by Shimadzu Corporation and a UV-visible spectrophotometer SPD-6AV type were used. The detection wavelength was 254 nm, and the solvent was tetrahydrofuran. Polystyrene conversion was used.

(2) Glass transition point (Tg)
According to JIS-K7121, a glass transition point (Tg) (extrapolated glass) was scanned from a chart scanned at a heating rate of 10 ° C./min using an input-compensated differential scanning calorimeter (Diamond DSC manufactured by PerkinElmer). The transition start temperature (° C.) was read.

(3) Softening point (Ts)
Using a thermomechanical analyzer (TMA) manufactured by TA Instruments, the resin is cut to a thickness of about 2 mm, a probe with a diameter of 3 mmφ is placed on the resin, and a force of 177 mN is applied under a nitrogen atmosphere to -50 ° C to 2 The temperature at the intersection point of the tangent line drawn at the inflection point when the temperature was raised at a rate of temperature rise of ° C./min was defined as Ts.

(4) Composition of polyester NMR measurement apparatus manufactured by JEOL Ltd. JNM-LA400 type was used to perform ¹ H-NMR measurement, and the composition was determined from the peak intensity of each copolymer component. As a measuring solvent, deuterated trifluoroacetic acid was used.

(5) Solubility The polyester resin (A) or (B) was dissolved in a mixed solvent of 8/2 (mass ratio) of toluene / methyl ethyl ketone so that the solid content concentration was 10% by mass, and the solubility was visually evaluated. . That is, those that were uniformly dissolved were evaluated as good solubility (◯), and the others were evaluated as insoluble (x).

(6) Conductive adhesiveness The polyester resin composition was dissolved in a mixed solvent of toluene / methyl ethyl ketone 8/2 (mass ratio) so as to have a solid content concentration of 30% by mass, and the dissolved solution was a copper plate having a thickness of 0.3 mm. The laminate sheet was applied using a bar coater and heat-treated at 120 ° C. for 2 minutes to prepare a laminate sheet having an adhesive layer having a dry thickness of 20 μm. The laminating sheet was laminated with a non-corona surface of a PET (polyethylene terephthalate) film having a wall thickness of 38 μm and pressed at a temperature of 180 ° C. and a pressure of 100 kPa for 1 minute for lamination. The obtained laminate sheet was molded into a width of 25 mm, a 180 ° peel test was performed at 23 ° C., and the peel strength was measured.

As shown in Table 1, the case of 25 N / 25 mm width or more was evaluated as excellent (◎), the case of 17 N / 25 mm width or more and less than 25 N / 25 mm width was evaluated as good (◯), and 14 N / 25 mm. A case where the width was greater than the width and less than 17 N / 25 mm width was evaluated as slightly defective (Δ), and a case where the width was less than 14 N / 25 mm width was evaluated as defective (×).

(7) Heat resistance In the same manner as in the case of (6) above, a laminate sheet was formed to a width of 25 mm, a 180 ° peel test was performed at 60 ° C., and the peel strength was measured. A similar test was conducted under the condition of 23 ° C., and the strength retention rate was determined by comparing the peel strength at 23 ° C. with the peel strength at 60 ° C., and the heat resistance was evaluated.

  As shown in Table 1, when the strength retention is 90% or more, it is evaluated as excellent (（), and when it is 70% or more and less than 90%, it is evaluated as good (◯), and 50% or more and less than 70%. Was evaluated as slightly defective (Δ), and the case of less than 50% was evaluated as defective (×).

(8) Anti-blocking property The polyester resin composition is dissolved in a mixed solvent of toluene / methyl ethyl ketone 8/2 (mass ratio) so as to have a solid content concentration of 30% by mass, and the solution is dissolved in a PET film having a thickness of 38 μm. The laminate was coated on the corona surface using a bar coater and heat treated at 120 ° C. for 1 minute to produce a laminate sheet having an adhesive layer having a dry thickness of 15 μm. The non-corona surface of a PET film having a thickness of 38 μm was placed on the adhesive surface of this sheet and pressed at 60 ° C. for 24 hours at a pressure of 50 hPa. Then, it shape | molded to 25 mm width, the 180 degree peel test was performed at 23 degreeC, and peel strength was measured.

  As shown in Table 1, when the peel strength is less than 3 N / 25 mm width, it is evaluated as excellent (◎), and when it is 3 N / 25 mm width and less than 8 N / 25 mm width, it is evaluated as good (◯). The case of 83 N / 25 mm width or more and less than 11 N / 25 mm width was evaluated as slightly defective (Δ), and the case of 11 N / 25 mm width or more was evaluated as defective (x).

(9) Particle size distribution of solution The polyester resin composition is dissolved in a mixed solvent of 8/2 (mass ratio) of toluene / methyl ethyl ketone so that the solid content concentration is 30% by mass, and laser diffraction type particle size distribution manufactured by Horiba Ltd. The median diameter was measured using a measuring apparatus LA-500.

(10) Solution characteristics The polyester resin composition was dissolved in a mixed solvent of toluene / methyl ethyl ketone 8/2 (mass ratio) so as to have a solid concentration of 30% by mass, and the solution was allowed to stand for 2 hours and 24 in a transparent glass bottle. It left still for time and it was confirmed visually whether the layers were separated. The case where the layers were separated in 2 hours was evaluated as defective (×), and the layer was not separated in 2 hours, but the case where the layers were separated in 24 hours was evaluated as slightly poor (Δ), and the layers were not separated for 24 hours or more. The thing was evaluated as good (◯).

(11) Acid value Dioxane / water (9/1 volume ratio) was added to 0.5 g of the sample, heated and refluxed, titrated with KOH methanol solution (concentration: 100 mol / m ³ ) using cresol red as an indicator, and titrated. The acid value was determined from the amount.

(12) Comprehensive evaluation It evaluated as a pass ((circle)) or a disqualification (x).

Next, a synthesis example of a polyester resin will be described.
[Synthesis Example A1]
The raw material was put into an esterification reaction can so that it might be 62 mol% terephthalic acid, 10 mol% isophthalic acid, 28 mol% sebacic acid, 53 mol% ethylene glycol, 47 mol% neopentylglycol, Then, esterification was performed at 250 ° C. for 5 hours under a controlled pressure of 0.25 MPa while stirring at 100 rpm. Next, it is transferred to a polycondensation can and charged with a polymerization catalyst. The pressure is gradually reduced to 1.3 hPa over 60 minutes, and then a polycondensation reaction is performed at 260 ° C. until a predetermined molecular weight is reached. The polyester resin (A1) was obtained. The obtained resin (A1) had a number average molecular weight of 26000, Tg of 9 ° C., an acid value of 2.5 mgKOH / g, and Ts of 63 ° C.

[Synthesis Example B1]
The raw materials were put into an esterification reaction can so as to have the composition shown in Table 2. Otherwise, after performing a polycondensation reaction in the same manner as for the polyester resin (A1), 1 mol% of trimellitic anhydride was added as a raw material for acid modification, and the mixture was stirred for 1 hour at normal pressure. (B1) was obtained. The obtained resin (B1) had a number average molecular weight of 11,000, Tg of 65 ° C., acid value of 7.1 mgKOH / g, and Ts of 114 ° C.

[Synthesis Examples A2 to A3, Synthesis Examples B2 to B13]
Resin was synthesized according to B1 when trimellitic anhydride was used as the raw material for acid modification, and according to A1 otherwise.

  Table 2 shows details of the polyester resins (A1) to (A3) and the polyester resins (B1) to (B13).

Example 1
The polyester resin (A1) and the polyester resin (B1) are charged into a glass bottle at a blending ratio shown in Table 3, and the concentration of the total resin solids of the resin (A1) and the resin (B1) is 30% by mass. Then, a mixed solvent in which toluene: methyl ethyl ketone was in a mass ratio of 8: 2 was added. The bottle was then sealed and the resin was dissolved in the solvent by using a paint shaker.

  As a result, the solution was not separated into layers. That is, the solution characteristics were good (◯). The conductive adhesive strength of the adhesive formed with this solution was 26 N / 25 mm width, and the conductive adhesiveness was excellent (◎). The conductor adhesive strength at 60 ° C. was 24 N / 25 mm width, and therefore the strength retention was 92% and the heat resistance was excellent (（). The anti-blocking property was good (◯) with a peel strength as small as 4 N / 25 mm width. The median diameter was 61 μm.

  Furthermore, 15 parts by mass of hexabromobenzene, 5 parts by mass of antimony trioxide, 7 parts by mass of titanium dioxide, 2 parts by mass of silicon dioxide, and 1 part of aluminum hydroxide are added to 100 parts by mass of the above solution. An adhesive containing an additive was obtained by adding part by mass and stirring until uniform.

  This adhesive was applied to a PET film having a thickness of 25 μm and dried at 120 ° C. for 2 minutes to obtain a laminated film having a thickness of 50 μm. When this laminated film was used to evaluate conductor adhesion, heat resistance, and anti-blocking properties, all were equivalent to the evaluation results of the adhesive containing no additive.

Examples 2-7 and 9, and Reference Examples 8 and 10
The polyester resins (A) and (B) were set to the types and blending ratios shown in Table 3. Otherwise, an adhesive was prepared and evaluated in the same manner as in Example 1. The results are shown in Table 3.

  As shown in Table 3, Examples 1 to 7 were all excellent in conductor adhesion, heat resistance, and antiblocking properties.

In Reference Example 8, although the acid value of the polyester resin (B12) was too high and the cohesive force was lowered, the conductor adhesive force was slightly low, but it was not a physical property that caused a great hindrance, and the overall evaluation passed (○ )Met.

  In Example 9, the content of propylene glycol (aliphatic polyhydric alcohol in which one or more hydrocarbons having 1 or more carbon atoms are bonded to one monomer molecule) of the polyester resin (B13) is increased to 80 mol%. Although the compatibility of the solution in which the polyester resin (A) and the polyester resin (B) were mixed and dissolved was improved, the conductor adhesive force was slightly low, but other than that, there was no particular problem. Was a pass (○).

In Reference Example 10, the acid value of polyester B7 was low, and the dissolution characteristics were not satisfactory in layer separation at 2 hours, but were separated at 24 hours and were slightly poor (Δ). Moreover, the median diameter was also slightly large at 221 μm. However, there was no problem other than that, and the comprehensive evaluation was a pass (◯).

Comparative Examples 1-7
The polyester resin (A) and the polyester resin (B) were set to the types and blending ratios shown in Table 4. Otherwise, an adhesive was prepared and evaluated in the same manner as in Example 1. The results are shown in Table 4.

  In Comparative Example 1, the blending ratio of the polyester resin (A) was less than the range of the present invention, and therefore the conductor adhesiveness was lowered. In Comparative Example 2, the blending ratio of the polyester resin (B) was less than the range of the present invention, and thus antiblocking properties and heat resistance were lowered. In Comparative Example 3, the glass transition point of the polyester resin (A) was higher than the range of the present invention, and thus the conductor adhesiveness was lowered. In Comparative Example 4, a monomer having a bisphenol A skeleton was not introduced into the polyester resin (B), and thus heat resistance and antiblocking properties were reduced. In Comparative Example 5, the Tg of the polyester resin (B) was low, so that the heat resistance and antiblocking property were lowered. In Comparative Example 6, since the content of the monomer having the bisphenol A skeleton of the polyester resin B is too large, the adhesive at the stage where no additive is contained is easily separated into layers, and the median diameter is increased. And anti-blocking property decreased.

  In Comparative Example 7, the polyester resin (B) contained neither terephthalic acid nor isophthalic acid, and thus became a resin having a low softening point, resulting in a decrease in heat resistance and antiblocking property.

Claims (3)

An organic solvent, and a polyester resin composition dissolved in the organic solvent so as to have a solid content concentration of 30% by mass,
The polyester resin composition has a polyester resin (A) having an acid value of 2.0 to 30 mgKOH / g and a glass transition point of 30 ° C. or less, and a polyester resin having an acid value of 2.0 to 30 mgKOH / g and a glass transition point of 50 ° C. or more ( B) and the polyester resin (B) contains at least one of terephthalic acid and isophthalic acid as an acid component and 1 to 70 mol% of a polyhydric alcohol having a bisphenol skeleton as an alcohol component The compounding ratio of the resin (A) and the resin (B) is (A) / (B) = 90 / 10-50 / 50 (mass ratio),
Adhesive, wherein the organic solvent is a mixed solvent solution of 8/2 (weight ratio) of toluene / methyl ethyl ketone. The polyester resin (B) has an aliphatic polyhydric alcohol in which one or more hydrocarbons having 1 or more carbon atoms are bonded to one monomer molecule in the side chain with respect to all alcohol components of the polyester resin (B). the adhesive of claim 1, wherein 1 to 70 mol% including it. A laminate comprising a resin layer formed using the adhesive according to claim 1 and 2 and containing two or more resin layers.