JP2009249472A - Crystalline polyester resin, adhesive composition, adhesion sheet, and flexible flat cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a crystalline polyester resin which has excellent adhesiveness and heat resistance and shows excellent solubility in general solvents and whose dissolved product has satisfactory shelf stability and to obtain an adhesive composition having adhesiveness especially to tin-plated copper and electrolytic copper foil and excellent heat resistance. <P>SOLUTION: The crystalline polyester resin contains 55 to 80 mol% 1,4-cyclohexane dimethanol as a glycol component and has -20 to 30°C glass transition temperature, 145 to 170°C melting point and 3 to 10 mJ/mg heat of crystal fusion. The crystalline polyester resin is dissolved in a solvent and an additive and the like are suitably mixed to form the adhesive composition. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is excellent in adhesiveness to various plastic films, wood, paper, leather, metals, etc., and in particular, in flexible flat cable applications used for wiring of electric and electronic devices, polyester film, tin-plated copper and A crystalline polyester resin having excellent adhesion and heat resistance to electrolytic copper foil, excellent solubility in general-purpose solvents, and good storage stability, and an adhesive composition using the same It is.

  Conventionally, polyester resins have been used as adhesives for various materials. Currently, solvent-free hot-melt adhesives and solvent-based solvent-based adhesives are used differently depending on applications and devices used. In recent years, solvent-free hot-melt adhesives tend to be used frequently due to environmental problems, etc., but there is still a lot of demand due to the thin film coating that is characteristic of solvent-based adhesives and ease of work. There is a need for a solvent-based adhesive having performance equivalent to that of a melt adhesive, soluble in a solvent, and excellent in storage stability.

  Amorphous polyester resin is easily soluble in solvents, so it is easy to obtain solvent-based adhesives, but generally it has poor heat resistance and low cohesion, so the resulting solvent-based adhesives have low adhesion. It tends to be. On the other hand, a crystalline polyester resin that is generally used as a hot melt adhesive is excellent in cohesive force, and is expected to be able to obtain a solvent-based adhesive with good adhesiveness. It is very difficult to obtain a solvent-based adhesive because of its low solubility.

To solve this problem, as shown in Patent Document 1, a method of melt-mixing a crystalline polyester resin and a non-crystalline polyester resin soluble in a solvent has been proposed. The problem of having to install a new device.
JP-A-4-164957

  The crystalline polyester resin that has been used in hot melt adhesives that have been used in various applications so far, for example, has been cited as a required performance, even though high heat resistance has been cited as a required performance. In order to place importance on production efficiency, the melting point of the resin has been lowered to achieve low temperature lamination. When such a crystalline polyester resin is used in a solvent-based adhesive, the melting point of the resin is low, so that depending on the application and usage environment, the resin softens and flows, so that workability is reduced and cohesive force is reduced. As a result, the adhesive properties tend to be deteriorated, and the adhesive properties tend to be impaired. On the other hand, if the melting point of the resin is increased, the solvent solubility tends to be very poor, and it is difficult to obtain a solvent-based adhesive. Therefore, in order to obtain a solvent-based adhesive, it is very important to balance these characteristics.

For example, Patent Document 2 proposes a crystalline polyester resin having improved solvent solubility and storage stability. When these resins were examined, they were excellent in solubility and stability, but because of their low melting point, they seem to have insufficient heat resistance and cannot be used in high temperature environments. In addition, when actually using a resin, it is necessary to increase the solid concentration of the resin relative to the varnish, considering the productivity, cost, etc., but the solution stability at a level that does not cause any practical problems. It is very difficult to make sex possible.
JP-A-6-184515

  In particular, when used as an adhesive for electrical and electronic equipment wiring, etc., it is necessary to satisfy the required performance of the heat resistance, blocking resistance, and adhesiveness of the adhesive layer. There is a need for a solvent-based adhesive that is soluble in a solvent and excellent in storage stability.

  A multi-core flat type flexible flat cable (hereinafter sometimes abbreviated as FFC) frequently used for wiring between circuit boards of electric and electronic devices is an insulating film made of tin-plated copper, which is a conductor, through an adhesive. For example, a laminated structure of insulating film / adhesive / metal conductor / adhesive / insulating film. As the insulating film, a biaxially stretched polyethylene terephthalate film layer having excellent mechanical properties and electrical properties is often used.

  Conventionally, solvent-free hot-melt adhesives and solvent-based solvent-based adhesives are used separately for FFC adhesives. Crystalline polyester resins are used as hot-melt adhesives, and amorphous materials are used as solvent-based adhesives. Resin is used. An amorphous polyester resin is easily soluble in a solvent, but generally has poor heat resistance, and its cohesive force is small, so that the adhesiveness is also low. On the other hand, a crystalline polyester resin generally used as a hot-melt adhesive is generally a solvent-based polyester resin system that has excellent cohesive strength and good adhesion, but is generally poorly soluble in solvents and can satisfy both. Obtaining an adhesive is very difficult. In recent years, solvent-free hot-melt adhesives have been increasing due to demands for heat resistance and environmental issues, but demand is still high due to the thin film coating that is characteristic of solvent-based adhesives and the ease of work. Therefore, there is a demand for a crystalline polyester adhesive that has performance equivalent to that of a hot melt adhesive, is soluble in a solvent, and has excellent storage stability.

  In particular, recently, FFC is often used in various parts of automobile applications, and accordingly, it is also used in parts where the use environment temperature is high, and the demand for heat resistance is further increased. Conventional crystalline polyester resins that are soluble in amorphous polyester resins and solvents have insufficient heat resistance, and mechanical strength decreases in an atmosphere of 90 ° C. or higher, resulting in poor adhesion or adhesives. The layer is deformed and cannot be used. In other words, there is a need for a crystalline polyester resin that has excellent heat resistance, blocking resistance, adhesion, solubility in general-purpose solvents, and excellent stability even in varnishes with a high solid content. Yes.

  The present invention is excellent in adhesiveness to various plastic films, wood, paper, leather, metals, etc., and in particular, in flexible flat cable applications used for wiring of electric and electronic devices, polyester film, tin-plated copper and A crystalline polyester resin having excellent adhesion and heat resistance to an electrolytic copper foil, excellent solubility in general-purpose solvents, and having a good storage stability in a dissolved material, and an adhesive composition using the same It is about things.

As a result of intensive studies, the present inventors have found that the above problems can be solved by the following means, and have reached the present invention. That is, the present invention has the following configuration.
(1) When the total amount of all glycol components of the polyester resin is 100 mol%, the glycol component contains 55 to 80 mol% of 1,4-cyclohexanedimethanol, and the glass transition temperature is -20 ° C to 30 ° C. A crystalline polyester resin having a melting point of 145 ° C. to 170 ° C. and a heat of crystallization melting of 3 mJ / mg to 10 mJ / mg.
(2) An adhesive composition comprising the polyester resin according to (1) and an organic solvent.
(3) An adhesive sheet having a structure in which an adhesive layer containing the polyester resin according to (1) and an insulating film are laminated.
(4) A flexible flat cable including the adhesive sheet according to (3) as a constituent element.
Details of the present invention will be described below.

  According to the present invention, it is excellent in adhesiveness to various plastic films, wood, paper, leather, metal, etc., and particularly in flexible flat cable applications used for wiring of electric and electronic devices, polyester film, tin-plated copper and A crystalline polyester resin having excellent adhesion and heat resistance to an electrolytic copper foil, excellent solubility in general-purpose solvents, and having a good storage stability in a dissolved material, and an adhesive composition using the same Things can be obtained.

  As a glycol component which comprises the crystalline polyester resin of this invention, 1, 4- cyclohexane dimethanol 55-80 mol%, Preferably it is 55-75 mol%, More preferably, it is 60-70 mol%. If it is less than 55 mol%, the crystallinity and mechanical strength of the resin will be insufficient, and the adhesiveness and heat resistance will decrease. If it is 80 mol% or more, the solubility in the solvent and the storage stability will decrease. It tends to end up.

  As the glycol component constituting the crystalline polyester resin of the present invention, ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 2-methyl-1 in addition to 1,4-cyclohexanedimethanol , 3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5 -Pentanediol, neopentyl glycol, diethylene glycol, triethylene glycol, dipropylene glycol, 2,2,4-trimethyl-1,5-pentanediol, ethylene oxide adduct and propylene oxide adduct of bisphenol A, hydrogenated bisphenol A Ethylene oxide adducts and propylene oxide Id adduct, 1,9-nonanediol, 2-methyl-octanediol, 1,10-decanediol, polytetramethylene glycol, polypropylene glycol, polyethylene glycol, polycarbonate glycol. Among these glycol components, ethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, polytetramethylene glycol, polypropylene glycol, polyethylene glycol, polycarbonate Glycol is particularly preferable from the viewpoint of heat resistance, solubility in a solvent, and storage stability.

  Polytetramethylene glycol, polypropylene glycol, polyethylene glycol, and polycarbonate glycol, which are polyalkylene ether glycols, preferably have molecular weights of 500 to 5,000. If the molecular weight is less than 500, the compatibility with the aromatic polyester segment increases, and the cohesive strength of the resin tends to decrease and the adhesive strength tends to decrease. On the other hand, if the molecular weight exceeds 5000, the compatibility with the aromatic polyester segment tends to be low, and a uniform solution tends to be difficult to obtain.

As the dibasic acid component of the crystalline polyester resin used in the present invention, the following polyvalent carboxylic acids, or alkyl esters or acid anhydrides thereof can be used.
Examples of the polyvalent carboxylic acid include terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, and 2,2′-diphenyl. Aromatic dibasic acids such as dicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, adipic acid, azelaic acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid Acids, 4-methyl-1,2-cyclohexanedicarboxylic acid, dimer acid and other aliphatic and alicyclic dicarboxylic acids, trimellitic acid, pyromellitic acid, benzophenone tetracarboxylic acid, biphenyltetracarboxylic acid, ethylene glycol bis ( Anhydrotrimellitate), glycerol tris And aromatic polycarboxylic acids anhydrotrimellitate), and the like. Considering heat resistance and flexibility, terephthalic acid is preferably 40 mol% or more of the total acid components.

  The glass transition temperature of the polyester resin of the present invention is -20 ° C to 30 ° C, preferably -15 ° C to 25 ° C, more preferably -10 ° C to 20 ° C. When the glass transition temperature is less than −20 ° C., the elastic modulus at a high temperature is lowered, and the adhesive force may be insufficient. For example, when it is used as an adhesive for automobile parts and home appliances, the adhesive strength may decrease in a high temperature environment in summer, and it may be difficult to sufficiently bond the parts to each other. Furthermore, resin blocking may easily occur, and it may be difficult to handle a substrate such as a film after applying an adhesive. On the other hand, if the glass transition temperature exceeds 30 ° C., the modulus of elasticity near room temperature becomes high, and the resin itself is too stiff so that adhesion to the adherend may not be exhibited.

  In the present invention, the crystalline polyester resin is a polyester resin in which a melting point peak is observed by differential scanning calorimetry (temperature increase rate: 20 ° C./min). Melting | fusing point is 145-170 degreeC, Preferably it is 150-165 degreeC, More preferably, it is 150-160 degreeC. When the melting point of the resin is less than 120 ° C., the solubility in the solvent is good, but the heat resistance tends to decrease, and when the melting point of the resin exceeds 170 ° C., the heat resistance is improved, The solubility and storage stability tend to be greatly reduced.

  The heat of crystallization melting of the polyester resin of the present invention (differential scanning calorimeter measurement, heating rate 20 ° C./min) is 3 mJ / mg to 10 mJ / mg, preferably 3 mJ / mg to 9 mJ / mg, more preferably 3 mJ / mg. ~ 8 mJ / mg. If the heat of crystallization and melting is lower than 3 mJ / mg, the cohesive strength of the resin is low and the adhesive strength is lowered. On the other hand, when the heat of crystallization and melting is higher than 10 mJ / mg, solubility in a solvent and storage stability tend to be lowered.

    The solvent used in the adhesive composition of the present invention preferably contains at least one solvent selected from toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, and ethyl acetate, and the five solvents are in all the solvents. It is still more preferable that it is 20 mass% or more. The five types of solvents are industrial general-purpose solvents having a boiling point of 70 to 140 ° C., and are excellent in cost and workability. If necessary, cyclohexanone, tetrahydrofuran, dimethylformamide, dioxane, dioxolane, phenol, benzyl alcohol, acetate-based organic solvents, and cellosolve-based organic solvents (the cyclohexanone and below, cellsolve-based organic solvents, as well as solvents such as cyclohexanone, etc. Can be used in combination. When a solvent such as cyclohexanone is used in combination, the storage stability of the adhesive composition can be improved as compared with the case where only the above five solvents are used, but the solvent price is high and the boiling point of the solvent is high. There is one or a plurality of problems that it is likely to remain in the film and the solvent is highly harmful, and it is not preferred for industrial use. Chlorinated solvents such as dichloromethane, dichloroethane, trichloromethane, and trichloroethane are also effective in greatly improving the dissolution stability and can be used alone or in combination with the above-mentioned five solvents. In some cases, it may be difficult to actually use.

  In the present invention, the crystalline polyester is dissolved at a solid concentration of 15% by mass in at least one mixed solvent in which the total concentration of toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, and ethyl acetate is 20% by mass or more of the total mixed solvent. The solution viscosity (measured at 25 ° C.) measured with a B-type viscometer when the dissolved material is stored at 25 ° C. for 5 days is preferably 1.5 times or less immediately after dissolution.

  In the adhesive composition of the present invention, the blending ratio of the polyester resin and the solvent is 10/90 to 30/70% by mass, preferably 15/90 to 25/75% by mass. If the concentration of the polyester resin is greater than 30% by mass, the adhesive will have poor dissolution stability, and if it is less than 10% by mass, an operation such as increasing the number of times the adhesive is applied is required to increase the thickness of the adhesive layer. As a result, work efficiency is poor and productivity is lowered.

  The reduced viscosity (unit dl / g) of the polyester resin of the present invention is 0.60 to 0.95, preferably 0.65 to 0.90, and more preferably 0.70 to 0.85. If the reduced viscosity is less than 0.60, the cohesive strength of the polyester resin may be low and the adhesive force may be reduced. If the reduced viscosity is more than 0.95, it may be hardly soluble in the solvent.

  The polyester resin of the present invention can be used in an adhesive composition by mixing various additives with the aforementioned solvent. As an additive, it is preferable to mix and use a flame retardant, a pigment, and an antiblocking agent. As flame retardants, brominated flame retardants such as decabromodiphenyl ether, bis (pentabromophenyl) ethane, tetrabromobisphenol A, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, triethyl phosphate, cresyl Diphenyl phosphate, xylenyl diphenyl phosphate, cresyl bis (2,6-xylenyl) phosphate, 2-ethylhexyl phosphate, dimethyl ethyl phosphate, resorcinol bis (diphenyl) phosphate, bisphenol A bis (diphenyl) phosphate, Bisphenol A bis (dicresyl) phosphate, diethyl-N, N-bis (2-hydroxyethyl) aminomethyl phosphate, phosphoric acid amide, organic phosphate Phosphorus flame retardants such as fin oxide and red phosphorus, ammonium polyphosphate, phosphazene, cyclophosphazene, triazine, melamine cyanurate, succinoguanamine, ethylene dimelamine, triguanamine, triazinyl cyanurate, melem, melam, tris (Β-cyanoethyl) isocyanurate, acetoguanamine, guanylmelamine sulfate, melem sulfate, melam sulfate, nitrogen flame retardants, potassium diphenylsulfone-3-sulfonate, aromatic sulfonimide metal salt, polystyrene sulfonate alkali metal salt, etc. Metal salt flame retardant, aluminum hydroxide, magnesium hydroxide, dolomite, hydrotalcite, barium hydroxide, basic magnesium carbonate, zirconium hydroxide, tin oxide and other hydrated metal compound flame retardants, silica, Aluminum oxide, iron oxide, titanium oxide, manganese oxide, magnesium oxide, zirconium oxide, zinc oxide, molybdenum oxide, cobalt oxide, bismuth oxide, chromium oxide, tin oxide, antimony oxide, nickel oxide, copper oxide, tungsten oxide, boric acid Inorganic flame retardants such as zinc, zinc metaborate, barium metaborate, zinc carbonate, magnesium carbonate, calcium carbonate, barium carbonate, zinc stannate, and silicon flame retardants such as silicone powder. Of these, brominated flame retardants such as bis (pentabromophenyl) ethane are particularly preferably used. Two or more of these flame retardants can be used in combination, and a combination of a brominated flame retardant such as bis (pentabromophenyl) ethane and an inorganic flame retardant such as antimony oxide is particularly preferable. As the pigment, titanium oxide, carbon black, or the like is used. Silica, calcium carbonate, talc and the like are used as the antiblocking agent, and silica is particularly preferable from the viewpoint of adhesiveness.

  If necessary, the adhesive composition of the present invention may contain a silane coupling agent, a tackifier, a crystal nucleating agent, an ultraviolet absorber, an epoxy compound, an isocyanate compound, and the like.

  The FFC typically has a structure in which tin-plated copper, which is a conductor, is bonded to an insulating film via an adhesive, that is, a laminated structure such as an insulating film / adhesive / metal conductor / adhesive / insulating film. Have.

  Examples of the insulating film used in the present invention include polyethylene terephthalate film (hereinafter abbreviated as PET film), polyethylene naphthalate film, polyamide film, polycarbonate film, polypropylene film, polystyrene film, polyimide film, polyamide film, polyoxabenzazole film, and the like. Any plastic film can be used, but a polyethylene terephthalate film is preferable in terms of economy and versatility. The plastic film can be provided with a corona treatment or an easy adhesion layer as necessary.

  An adhesive sheet can be obtained by applying the adhesive composition of the present invention to an insulating film so that the thickness after drying is 5 μm or more and 60 μm or less to obtain a dried laminate. FFC can be manufactured by manufacturing the adhesive sheet with the coating layer on the inside and sandwiching and bonding the conductor.

  In order to describe the present invention in more detail, examples are given below, but the present invention is not limited to the examples. In the examples, “parts” means parts by mass. In addition, the measured value described in the Example is measured by the following method.

Resin composition: The resin was dissolved in deuterated chloroform, and ¹ H-NMR analysis was performed using a nuclear magnetic resonance analyzer (NMR) Gemini-200 manufactured by Varian Inc., and the integral ratio was determined.

  Melting point, heat of crystallization melting, glass transition temperature: Using a differential scanning calorimeter, put 5 mg of a measurement sample into an aluminum pan, seal with a lid, and make a differential scanning calorimeter (DSC) DSC- manufactured by Seiko Instruments Inc. 220, the temperature was raised from room temperature to 260 ° C. at a temperature raising rate of 20 ° C./min. Next, after rapidly cooling from 250 ° C. to −100 ° C. at a temperature decrease rate of 50 ° C./min, the temperature was immediately increased again to 260 ° C. at a temperature increase rate of 20 ° C./min. In DSC measurement after quenching, the temperature showing the maximum value of the melting peak was taken as the melting point, and the heat of crystallization melting was calculated from the area of the melting peak. Moreover, the temperature of the intersection of the extended line of the base line below a glass transition temperature and the tangent which shows the maximum inclination in a transition part was made into the glass transition temperature.

Acid value: 0.2 g of polyester was dissolved in 20 ml of chloroform, and titrated with a 0.1 N potassium hydroxide ethanol solution to obtain an equivalent (eq / 10 ⁶ g) per 10 ⁶ g of resin.

Reduced viscosity: 0.1 g of polyester was dissolved in 25 cc of a phenol / tetrachloroethane (mass ratio 6/4) mixed solvent and measured at 30 ° C. using an Ubbelohde viscosity tube to reduce the reduced viscosity η _sp / C (dl / g). Asked.

Storage stability: The polyester resin was heated and mixed as necessary so that the solid content concentration was 15%, and dissolved in a mixed solvent of toluene / dichloromethane = 20/80% by mass. The solution on the left was transferred to a 200 mL mayonnaise bottle, immersed in a thermostat adjusted to 25 ° C., and left to stand for 2 hours. Next, the solution viscosity was measured using a B-type rotational viscometer (manufactured by Tokyo Keiki Co., Ltd., EM type), and this was taken as the viscosity immediately after dissolution. The solution on the left was sealed and stored for 5 days in a dark place at 25 ° C., and the viscosity of the solution was measured again using a B-type rotational viscometer. .
The solution viscosity after 7 days is 1.0 times or more and less than 1.3 times immediately after dissolution:
The solution viscosity after 7 days is 1.3 times or more and less than 1.5 times immediately after dissolution: ○
The solution viscosity after 7 days is 1.5 times or more and less than 2.0 times immediately after dissolution: Δ
The solution viscosity after 7 days is 2.0 times or more immediately after dissolution: ×

<Synthesis example 1 of crystalline polyester resin>
In a reaction vessel equipped with a stirrer, thermometer, and distillation condenser, 299 parts of terephthalic acid, 50 parts of isophthalic acid, 110 parts of adipic acid, 30 parts of sebacic acid, 223 parts of ethylene glycol, 1,4-cyclohexanedi 324 parts of methanol, 0.4 part of tetrabutyl titanate and 0.7 part of Ciba Geigy's antioxidant “Irganox-1330” were added and gradually raised to 230 ° C. over 4 hours. The esterification reaction was carried out while removing. This was charged with 75 parts of polytetramethylene glycol having a number average molecular weight of 1000, then the reaction system was subjected to initial polymerization under reduced pressure to 10 mmHg over 20 minutes and the temperature was raised to 250 ° C., and further polymerization was conducted for 1.5 hours at 1 mmHg or less. Went. In this way, a crystalline polyester resin synthesis example 1 was obtained. Table 1 shows the results of composition analysis by ¹ H-NMR and characteristic values of crystalline polyester resin synthesis example 1.

<Preparation of Resin Solution of Crystalline Polyester Resin Synthesis Example 1>
In a reaction vessel equipped with a stirring blade, a thermometer, and a reflux condenser, 15 parts of crystalline polyester resin synthesis example 1, 17 parts of toluene and 68 parts of dichloromethane were charged and dissolved completely at 30 ° C. over 3 hours. A polyester resin solution was obtained. Table 1 shows the storage stability of the resin solution.

<Comparative synthesis example 1 of crystalline polyester resin>
Crystalline polyester resin comparative synthesis example 1 was synthesized in the same manner as in crystalline polyester resin synthesis example 1 except that the amounts of dicarboxylic acid component and glycol component were changed. Table 2 shows the compositional analysis results and characteristic values of ¹ H-NMR of Comparative Synthesis Example 1 of the crystalline polyester resin.
<Synthesis Example 2 of crystalline polyester resin>
In a reaction vessel equipped with a stirrer, thermometer, and distillation condenser, 299 parts of terephthalic acid, 25 parts of isophthalic acid, 153 parts of adipic acid, 166 parts of ethylene glycol, 122 parts of 1,4-butanediol, 1, 286 parts of 4-cyclohexanedimethanol, 0.4 part of tetrabutyl titanate and 0.7 part of Ciba Geigy's antioxidant “Irganox-1330” were added and gradually raised to 230 ° C. over 4 hours. Is removed from the system, the esterification reaction is carried out, and then the reaction system is subjected to reduced pressure initial polymerization to 10 mmHg over 20 minutes and the temperature is increased to 260 ° C., and the latter polymerization is further performed for 1.5 hours at 1 mmHg or less. went. A crystalline polyester resin synthesis example 2 was thus obtained. Table 1 shows the results of composition analysis by ¹ H-NMR and characteristic values of crystalline polyester resin synthesis example 2.

<Synthetic Examples 3-6 of Crystalline Polyester Resin, Comparative Synthetic Examples 2, 3 and Comparative Synthetic Examples 4-6 of Amorphous Polyester Resin>
Crystalline polyester resin synthesis examples 3 to 6, comparative synthesis examples 2 and 3, and amorphous polyester resin comparison, except that the amounts of dicarboxylic acid component and glycol component were changed, as in synthesis example 2 of crystalline polyester resin Synthesis of Synthesis Examples 4 to 6 was performed. Tables 1 and 2 show the compositional analysis results and characteristic values of the thus obtained crystalline polyester resin and amorphous polyester resin by ¹ H-NMR.

<Preparation of Resin Solutions of Polyester Resin Synthesis Examples 2-6 and Comparative Synthesis Examples 1-6>
In the same manner as in the case of the crystalline polyester resin synthesis example 1, polyester resin synthesis examples 2 to 6 and comparative synthesis examples 1 to 6 were dissolved in a solvent to obtain a polyester resin solution. Tables 1 and 2 show the storage stability of the crystalline polyester resin solution and the amorphous polyester resin solution thus obtained.

<Preparation of adhesive composition 1>
In a 70 ml glass bottle containing glass beads having a diameter of 2 mm, 666 parts of the crystalline polyester resin solution obtained in <Preparation of Resin Solution of Crystalline Polyester Resin Synthesis Example 1>, bis (pentabromophenyl) ethane (Albemarle) SAYTEX 8010 (manufactured by SA), 36 parts of antimony trioxide, 10 parts of titanium oxide, 4 parts of silica (Aerosil R972 manufactured by Nippon Aerosil Co., Ltd.), and dispersion for 3 hours using a shaker Agent composition 1 was obtained.
The composition of the adhesive composition 1 thus obtained is shown in Table 3.

<Preparation of adhesive compositions 2-6 and comparative compositions 1-6>
In the same manner as in the adhesive composition 1, using the resins obtained in Synthesis Examples 2 to 6 and Comparative Synthesis Examples 1 to 6 of the crystalline polyester resin, various additives are blended, and the intended adhesive composition 2 6. Comparative compositions 1-6 were obtained. The composition of the adhesive (comparative) composition thus obtained is shown in Table 3.

<Example 1>
The adhesive obtained with the adhesive composition 1 was evaluated according to the evaluation items as shown below.

Adhesive strength: The adhesive composition obtained in the adhesive composition 1 was applied on a 25 μm biaxially stretched PET film so that the thickness after drying was 30 μm, dried at 60 ° C. for 3 minutes, and then 120 ° C. And dried for 5 minutes to prepare an adhesive sheet. Using the roll laminator manufactured by Tester Sangyo Co., Ltd., the adhesive coated surface of the adhesive sheet thus obtained and the glossy surface of the electrolytic copper foil were subjected to conditions of a laminating temperature of 170 ° C., a pressure of 0.3 MPa, and a speed of 1 m / min. And pasted together. The bonded product thus obtained was cut to a width of 1 cm, and a tensile test was carried out using a RTM100 manufactured by Toyo Baldwin Co., Ltd. at a pulling rate of 50 mm / min in an atmosphere of 25 ° C. Was measured.
As the electrolytic copper foil, USLPSE-18 μm manufactured by Nippon Electrolytic Co., Ltd. was used.
(Determination) A: 20 N / cm or more B: 10 N / cm or more and less than 20 N / cm Δ: 5 N / cm or more and less than 10 N / cm ×: less than 5 N / cm

Heat resistance: The adhesive composition obtained in the adhesive composition 1 was applied on a 25 μm biaxially stretched PET film so that the thickness after drying was 30 μm, dried at 60 ° C. for 5 minutes, and then 120 ° C. And dried for 5 minutes to prepare an adhesive sheet. The adhesive sheet thus obtained was aligned in parallel so that 10 tin-plated copper wires having a width of 0.8 mm and a thickness of 0.05 mm were provided, and the distance between the copper wires was 1.0 mm. In a state where a 50 μm biaxially stretched polypropylene film was stacked as a release film, the film was laminated using a roll laminator manufactured by Tester Sangyo Co., Ltd. under the conditions of a laminating temperature of 150 ° C., a pressure of 0.3 MPa, and a speed of 1 m / min. Thereafter, the polypropylene film was removed, a tin-plated copper wire was turned upward, a weight was placed so as to be 1 N / cm ^2, and heat treatment was performed at 80 ° C. for 72 hours. The depth of the sinking of the tin-plated copper wire of the sample heat-treated in this way into the adhesive layer was measured.
(Judgment) ◎: Less than 2 μm ○: 2 μm or more and less than 5 μm Δ: 5 μm or more and less than 10 μm ×: 10 μm or more

<Examples 2-6 and Comparative Examples 1-6>
The results of evaluating the adhesive compositions 2 to 6 and the comparative compositions 1 to 6 in the same manner as the adhesive composition 1 are shown in Table 3.

Comparative composition 1 is excellent in heat resistance and adhesiveness, but inferior in storage stability. The crystalline polyester resin contained in the comparative composition 1 has a low melting point and a high crystallization melting heat, which is outside the scope of the claims.
Although the comparative composition 2 is excellent in heat resistance, it is inferior to adhesiveness and storage stability. The crystalline polyester resin contained in the comparative composition 2 has a high crystallization melting heat and a glass transition temperature, and is outside the scope of the claims.
Comparative composition 3 has excellent heat resistance, but is inferior in adhesiveness and storage stability. The crystalline polyester resin contained in the comparative composition 3 has a high melting point and heat of crystallization melting, and is outside the scope of the claims.
Although the comparative composition 4 and the comparative composition 5 are excellent in storage stability, the adhesiveness and heat resistance are inferior. The melting point of the polyester resin contained in the comparative composition 4 and the comparative composition 5 is not detected, and is outside the scope of the claims.
Comparative composition 6 has good adhesion and storage stability but is inferior in heat resistance. The polyester resin contained in the comparative composition 6 does not use 1,4-cyclohexanedimethanol and is amorphous, which is outside the scope of the claims.

The crystalline polyester resin and adhesive composition obtained in the present invention have superior heat resistance and superior adhesion to polyester film, tin-plated copper and electrolytic copper foil as compared with the prior art, and can be used as a general-purpose solvent. It exhibits excellent solubility and good storage stability. For this reason, it is useful as an adhesive composition, and exhibits excellent performance particularly in flexible flat cable applications used for wiring of electric and electronic devices.

Claims (4)

  When the total amount of all glycol components of the polyester resin is 100 mol%, the glycol component contains 55 to 80 mol% of 1,4-cyclohexanedimethanol, and the glass transition temperature is −20 ° C. to 30 ° C., melting point Is a crystalline polyester resin characterized by having a crystallization melting heat of 3 mJ / mg to 10 mJ / mg.   An adhesive composition comprising the polyester resin according to claim 1 and an organic solvent.   An adhesive sheet having a structure in which an adhesive layer containing the polyester resin according to claim 1 and an insulating film are laminated. A flexible flat cable comprising the adhesive sheet according to claim 3 as a constituent element.