Polyester resin, and adhesive composition, adhesive sheet, and laminate containing same

Abstract

The purpose of the present invention is to provide a polyester resin which has excellent storage stability and is capable of forming dense crosslinking while having a high reduced viscosity.　The polyester resin comprises 2.0 mol% or more of a tricarboxylic acid component with respect to all polycarboxylic acid components as100 mol%, the polyester resin being characterized in that the reduced viscosity of the polyester resin is 0.50 dl / g or more, the acid value (AV) of the polyester resin is 150 eq / t or more, and a ratio I(1785) / I(1715) between peak intensity I(1715) of absorbance at 1715 cm-1 and peak intensity I(1785) of absorbance at 1785 cm-1 measured by Fourier transform infrared spectroscopy (FTIR) is 0.030 or less.

Description

Polyester resin, and adhesive compositions, adhesive sheets, and laminates containing the same.

[0001] The present invention relates to polyester resins, and more particularly to polyester resins suitable for adhesive compositions for printed circuit boards used for bonding to substrates. The present invention also relates to polyester resins, adhesive compositions containing them, adhesive sheets and laminates, and further to printed circuit boards, laminated films for decorating three-dimensional molded products, films for laminating metal cans and packaging materials that include these as components.

[0002] In recent years, electronic devices have become smaller, lighter, more densely packed, and more powerful, leading to a growing demand for printed circuit boards (electronic circuit boards). Since printed circuit boards require heat resistance to withstand soldering during component mounting, adhesive compositions for printed circuit boards that can form a high crosslink density during curing are preferred.

[0003] To achieve a high crosslinking density during curing, the polyester resin used in the adhesive composition is first required to have a high acid value. As disclosed in Patent Document 1, in order to increase the acid value of the polyester resin, a prepolymer is generally obtained by esterifying a polycarboxylic acid component with a polyhydric alcohol component, and then modification with an acid anhydride is performed.

[0004] Japanese Patent Publication No. 2024-7384

[0005] Since adhesive compositions for printed circuit boards often contain fillers, it is important to increase the molecular weight of the polyester resin used and thereby increase its reduced viscosity. However, in the method described in Patent Document 1, when attempting to increase the molecular weight of the polyester resin and thus increase its reduced viscosity, the number of hydroxyl groups in the polyester resin decreases relatively, reducing the number of reaction sites with acid anhydrides and limiting the number of carboxyl groups that can be introduced.

[0006] Furthermore, polyester resins with a low glass transition temperature (Tg) have the characteristic of high wettability to substrates and good adhesion, and polyester resins with a Tg below room temperature are preferably used in this field. However, there is a problem that if such polyester resins are stored at a Tg above the Tg, the reduced viscosity of the polyester resin changes significantly, and such low-Tg resins are usually stored under refrigeration. Therefore, from the viewpoint of controlling the reduced viscosity of polyester resins, it is desirable that the change in reduced viscosity due to such storage be small, but the polyester resin in Comparative Example 2 of Patent Document 1 did not exhibit sufficient storage stability. Thus, a polyester resin that has excellent storage stability, high reduced viscosity, and can form a high crosslink density has not been provided until now.

[0007] This invention is based on the aforementioned prior art. Specifically, the object of this invention is to provide a polyester resin that has excellent storage stability and high reducing viscosity, while also being capable of forming a high crosslink density.

[0008] As a result of diligent research, the inventors of this invention have found that the above-mentioned problems can be solved by the means described below, and have arrived at the present invention. That is, the present invention consists of the following configuration.

[0009] [1] The polyester resin contains 2.0 mol% or more of tricarboxylic acid components out of 100 mol% of total polycarboxylic acid components, has a reduced viscosity of 0.50 dl / g or more, has an acid value (AV) of 150 eq / t or more, and is measured by Fourier transform infrared absorption spectroscopy (FTIR) at 1715 cm⁻¹ －１ The peak absorbance intensity I (1715) and 1785 cm⁻¹ are shown. －１[1] A polyester resin characterized in that the ratio of peak absorbance intensities I(1785) in the polyester resin, I(1785) / I(1715), is 0.030 or less. [2] The polyester resin according to [1], wherein the amount of unreacted tricarboxylic acid monomer is 1000 ppm or less. [3] The polyester resin according to [1] or [2], wherein the content of a tricarboxylic acid component in which three carboxyl groups form an ester bond is 2.0 mol% or less with respect to the total amount of polycarboxylic acids constituting the polyester resin. [4] The polyester resin according to any one of [1] to [3], wherein the content of antimony and zinc in the polyester resin is 200 ppm or less. [5] The polyester resin according to any one of [1] to [4], wherein the dicarboxylic acid component constituting the polyester resin is one or more selected from the group consisting of aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and aromatic dicarboxylic acids. [6] The polyester resin according to any one of [1] to [5], wherein the hydroxyl value (OHV) is 5 to 70 eq / t. [7] A polyester resin according to any one of [1] to [6], wherein the glass transition temperature (Tg) is 0 to 80°C. [8] A polyester resin according to any one of [1] to [7], wherein the weight-average molecular weight (Mw) is 20,000 to 300,000. [9] A polyester resin according to any one of [1] to [8], wherein the polycarboxylic acid component of tetravalent or higher is 6 mol% or less in 100 mol% of the polycarboxylic acid component.

[10] An adhesive composition comprising the polyester resin according to any one of [1] to [9].

[11] The adhesive composition according to

[10] for use in printed circuit boards.

[12] An adhesive sheet in which the adhesive composition according to

[10] is laminated on a release substrate.

[13] A laminate in which the adhesive composition according to

[10] is laminated on a substrate which is a resin substrate, a metal substrate, paper, or an inorganic nonmetal substrate.

[14] A printed circuit board comprising the laminate according to

[13] as a component.

[15] A laminated film for decorating three-dimensional molded articles, comprising a layer formed from the adhesive composition described in

[10] as a component.

[16] A film for laminating metal cans, comprising a layer formed from the adhesive composition described in

[10] as a component.

[17] A packaging material, comprising a layer formed from the adhesive composition described in

[10] as a component.

[18] Use of an adhesive composition containing a polyester resin according to any one of [1] to [9] for use in printed circuit boards.

[0010] According to the present invention, a polyester resin can be obtained that has excellent storage stability and high reducing viscosity, while also being capable of forming a high crosslink density.

[0011] <Polyester Resin> The polyester resin of the present invention contains 2.0 mol% or more of tricarboxylic acid components in 100 mol% of the total polycarboxylic acid components, has a reduced viscosity of 0.50 dl / g or more, has an acid value (AV) of 150 eq / t or more, and has a viscosity of 1715 cm as measured by Fourier transform infrared absorption spectroscopy (FTIR). －１ The peak absorbance intensity I (1715) and 1785 cm⁻¹ are shown. －１ The present invention is characterized in that the ratio of the peak absorbance intensities I(1785) at 1715 cm⁻¹ (I(1785) / I(1715)) (hereinafter sometimes simply referred to as the "IR spectral ratio") is 0.030 or less. The polyester resin of the present invention is characterized in that it contains a predetermined amount or more of tricarboxylic acid components, and both the reduced viscosity and acid value of the polyester resin are high. The polyester resin of the present invention is also characterized in that the IR spectral ratio is below a predetermined value. The IR spectral ratio defined in the present invention is the absorbance (1715 cm⁻¹) that is characteristic of the ester bond. －１ ) and the absorbance characteristic of the acid anhydride group (1785 cm⁻¹). －１ This is the ratio of ). Keeping these ratios below a predetermined value means that the proportion of unreacted tricarboxylic acid anhydride contained in the polyester resin is low. The inventors' research found that such a polyester resin exhibits small changes in reduced viscosity and excellent storage stability even when stored at Tg or above, and offers the advantage of eliminating the need for refrigeration equipment.

[0012] The polyester resin of the present invention has a chemical structure obtained by a polycondensate of a polycarboxylic acid component and a polyhydric alcohol component, preferably having a chemical structure obtained by a polycondensate of a dicarboxylic acid component and a tricarboxylic acid component and a diol component. In this disclosure, the polycarboxylic acid component includes a dicarboxylic acid component, a tricarboxylic acid component which is a trivalent polycarboxylic acid, and a polycarboxylic acid component which is tetravalent or higher, and the polyhydric alcohol component includes a diol component and a polyhydric alcohol component which is trivalent or higher. Furthermore, the various polycarboxylic acids exemplified below include not only the polycarboxylic acid itself, but also esters of the polycarboxylic acid and polycarboxylic acid anhydrides.

[0013] The dicarboxylic acid component and the diol component each consist of one or more selected components. The dicarboxylic acid component constituting the polyester resin is not particularly limited, but the dicarboxylic acids or their esters and dicarboxylic acid anhydrides listed below can be used. Specifically, examples of dicarboxylic acids include aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and aromatic dicarboxylic acids. Examples of aliphatic dicarboxylic acids include adipic acid, sebacic acid, dimer acid, fumaric acid, maleic acid, succinic acid, etc. Examples of alicyclic dicarboxylic acids include 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, tetrahydrophthalic acid, hexahydrophthalic acid, methyltetrahydrophthalic acid, etc. Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, 2,5-frandicarboxylic acid, 5-sodium sulfodimethylisophthalic acid and their esters and acid anhydrides can be used. From the viewpoint of improving the dielectric properties and solder heat resistance of the adhesive composition, aliphatic dicarboxylic acids and aromatic dicarboxylic acids are preferred as the dicarboxylic acid component, and it is more preferable to include at least an aromatic dicarboxylic acid. Preferred aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, and 2,5-franzicarboxylic acid, more preferably terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid, and even more preferably terephthalic acid and isophthalic acid. When an aromatic dicarboxylic acid is included, the aromatic dicarboxylic acid component is preferably 20 to 100 mol%, more preferably 40 to 90 mol%, and even more preferably 60 to 80 mol% of the 100 mol% of the dicarboxylic acid component constituting the polyester resin. Furthermore, when terephthalic acid and isophthalic acid are included as aromatic dicarboxylic acids, their content ratio (terephthalic acid:isophthalic acid) is preferably 5:95 to 95:5, more preferably 10:90 to 60:40, and even more preferably 20:80 to 40:60 on a molar basis. By keeping terephthalic acid within the aforementioned range, a polyester resin with excellent solubility is obtained. Furthermore, by keeping isophthalic acid within the aforementioned range, it becomes possible to obtain polyester resin at a low cost.

[0014] From the viewpoint of the hygroscopic properties of polyester resin, it is preferable to have a low content of aromatic dicarboxylic acids having sulfonic acid groups (e.g., sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, 5(4-sulfophenoxy)isophthalic acid, etc.). The content of aromatic dicarboxylic acids having sulfonic acid groups in 100 mol% of polycarboxylic acid components is preferably 10 mol% or less, more preferably 5 mol% or less, even more preferably 3 mol% or less, even more preferably 1 mol% or less, and particularly preferably 0 mol%.

[0015] The diol components constituting the polyester resin are not particularly limited, but examples include aliphatic diols, alicyclic diols, aromatic diols, and bisphenol skeleton-containing monomers. Examples of aliphatic diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 2-methyl-1,3-hexanediol, and 2-methyl-1,3-hexanediol. Tyl-2-ethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2-n-propyl-1,3-propanediol, 2,2-di-n-propyl-1,3-propanediol, 2-n-butyl-2-ethyl-1,3-propanediol, 2,2-di-n-butyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, dimergio Aliphatic diols such as diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polytetramethylene glycol, and polypropylene glycol can be used. Alicyclic diols such as 1,4-cyclohexanedimethanol and tricyclodecanedimethanol can be used. Aromatic diols such as diphenolic acids can be used. Bisphenol skeleton-containing monomers such as bisphenol A, bisphenol B, bisphenol E, bisphenol F, bisphenol AP, bisphenol BP, bisphenol P, bisphenol PH, bisphenol S, bisphenol Z, 4,4'-dihydroxybenzophenone, bisphenol fluorene and their hydrogenated products, and glycols such as ethylene oxide adducts and propylene oxide adducts obtained by adding 1 to several moles of ethylene oxide or propylene oxide to the hydroxyl group of bisphenols can be used. Aliphatic diols are preferred as diols. ２－６ Aliphatic diols are preferred.

[0016] From the viewpoint of heat resistance, low hygroscopicity, and long-term durability in a humid and hot environment, it is preferable to have a low content of ether-bonded glycols other than bisphenol skeleton-containing monomers such as diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. The content of such components is preferably 20 mol% or less, more preferably 10 mol% or less, even more preferably 5 mol% or less, even more preferably 1 mol% or less, and particularly preferably 0 mol% in 100 mol% of the diol.

[0017] As the diol component constituting the polyester resin, diols having an alkylene group with four or more carbon atoms are particularly preferred, and examples include 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 2-methyl-1,3-hexanediol, 2,4-diethyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, dimer diol, polytetramethylene glycol, etc., with 1,6-hexanediol being particularly preferred. Using a diol having an alkylene group with four or more carbon atoms tends to lower the glass transition temperature (Tg) of the polyester resin, and it is preferable that the diol component having an alkylene group with four or more carbon atoms constitutes 1 to 85 mol%, more preferably 10 to 80 mol%, and even more preferably 30 to 75 mol% of the total polyhydric alcohol component.

[0018] The diol component constituting the polyester resin may include a diol having an alkylene group with three or fewer carbon atoms, and examples include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 2-methyl-2-ethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2-n-propyl-1,3-propanediol, 2,2-di-n-propyl-1,3-propanediol, 2-n-butyl-2-ethyl-1,3-propanediol, and 2,2-di-n-butyl-1,3-propanediol. Among these, ethylene glycol, 2-methyl-1,3-propanediol, and neopentyl glycol are preferred, and 2-methyl-1,3-propanediol is even more preferred. Using a diol having an alkylene group with 3 or fewer carbon atoms tends to increase the glass transition temperature (Tg) of the polyester resin. Preferably, the diol component having an alkylene group with 3 or fewer carbon atoms is 1 to 100 mol%, more preferably 20 to 80 mol%, and even more preferably 40 to 60 mol% of the total polyhydric alcohol component.

[0019] The polyester resin of the present invention can also be copolymerized with lactones or lactams. For example, ε-caprolactone or ε-caprolactam can be used.

[0020] The polycarboxylic acid and polyhydric alcohol components constituting the polyester resin of the present invention can be derived from biomass resources. Biomass resources include materials obtained by the photosynthesis of plants, where sunlight energy is converted into starch, cellulose, and other forms and stored; the bodies of animals that feed on plants; and products made by processing plant or animal bodies. Among these, plant resources are more preferred as biomass resources, including, for example, wood, rice straw, rice husks, rice bran, old rice, corn, sugarcane, cassava, sago palm, okara (soy pulp), corn cob, tapioca residue, bagasse, vegetable oil residue, potatoes, buckwheat, soybeans, oils and fats, waste paper, papermaking residue, fishery residue, livestock excrement, sewage sludge, and food waste. More preferably, corn, sugarcane, cassava, and sago palm are used. Specific examples of polycarboxylic acid raw materials derived from biomass resources include, for example, adipic acid, sebacic acid, fumaric acid, itaconic acid, terephthalic acid, and 2,5-franzicarboxylic acid. Specific examples of polyhydric alcohol raw materials derived from biomass resources include, for example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,4-butanediol, and 1,4-cyclohexanedimethanol.

[0021] The polyester resin of the present invention may contain urethane bonds (-OCO-NH-), urea bonds (-NH-CO-NH-), ether bonds such as alkyl ether bonds and phenyl ether bonds (-O-), and carbonate bonds (-OCO-O-). However, from the viewpoint of low hygroscopicity and long-term durability in humid and hot environments, it is desirable that the content of these bonds be as low as possible. The concentrations of urethane bonds, urea bonds, ether bonds, and carbonate bonds in the polyester resin of the present invention are preferably 5 mmol / g or less, more preferably 3 mmol / g or less, more preferably 2 mmol / g or less, even more preferably 1 mmol / g or less, even more preferably 0.5 mmol / g or less, and particularly preferably 0.2 mmol / g or less. These concentrations can be measured by known methods such as NMR.

[0022] The polyester resin of the present invention is copolymerized with a tricarboxylic acid component (preferably at least a tricarboxylic acid anhydride as the tricarboxylic acid). Examples of the tricarboxylic acid component include trivalent aromatic carboxylic acids such as trimellitic acid, trimesic acid, and trimellitic anhydride (TMA), trivalent aliphatic carboxylic acids such as citric acid and citric anhydride, and trivalent alicyclic tricarboxylic acids such as 1,2,4-cyclohexanetricarboxylic acid, 1,3,5-cyclohexanetricarboxylic acid, and cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride. Among these, trivalent aromatic carboxylic acids are preferred, and trimellitic acid or trimellitic anhydride is more preferred. By copolymerizing the tricarboxylic acid component, it becomes easier to introduce the following tricarboxylic acid components into the main chain of the polyester resin: (1) a tricarboxylic acid component in which three carboxyl groups form ester bonds (with the polyester main chain) (hereinafter sometimes referred to as "triester"), (2) a tricarboxylic acid component in which two carboxyl groups form ester bonds (with the polyester main chain) and one carboxyl group remains in a free state (hereinafter sometimes referred to as "diester"), and (3) a tricarboxylic acid component in which one carboxyl group forms ester bonds (with the polyester main chain) and two carboxyl groups remain in a free state (hereinafter sometimes referred to as "monoester"). The triester can give the polyester a branched structure, thus contributing to the high molecular weight of the polyester resin. In the diester and monoester, the one or two carboxyl groups remaining in a free state contribute to the formation of high-density crosslinks.

[0023] The polyester resin of the present invention contains 2.0 mol% or more of the tricarboxylic acid component in 100 mol% of the total polycarboxylic acid component, preferably 2.0 to 10 mol%, more preferably 2.5 to 10 mol%, more preferably 3.0 to 9 mol%, and even more preferably 3.5 to 8 mol%. If the amount falls below the lower limit, it becomes difficult to increase the acid value of the polyester resin. Conversely, if it exceeds the upper limit, the tricarboxylic acid component tends to remain unreacted, which is undesirable.

[0024] In the polyester resin of the present invention, the content of the triester is preferably 0.5 to 2.0 mol%, more preferably 0.6 to 1.8 mol%, still more preferably 0.7 to 1.6 mol% based on the total amount of polycarboxylic acids constituting the polyester resin. By setting the lower limit value or more, it becomes easy to obtain a polyester resin capable of forming a high crosslink density when made into an adhesive composition. By setting the upper limit value or less, it becomes easy to suppress gelation during the production of the polyester resin. The content of the triester can be measured by H-NMR measurement, TOCSY spectrum measurement, etc. For example, １ It can be measured by H-NMR measurement, TOCSY spectrum measurement, etc. For example, １ In the case of H-NMR measurement and TOCSY spectrum measurement, first １ By H-NMR measurement, the integral value of the peak derived from the tricarboxylic acid component is calculated. Next, by TOCSY spectrum measurement, the integral values are calculated by separating the peaks forming the triester and the other peaks among the tricarboxylic acid components, so that the content of the tricarboxylic acid components that form the triester can be clarified.

[0025] The acid value (AV ２ ) of the carboxyl group attributed to the diester in the polyester resin of the present invention may be, for example, 20 eq / t or more, desirably 40 to 500 eq / t, preferably 50 to 500 eq / t, more preferably 55 to 400 eq / t, still more preferably 60 to 300 eq / t. In the diester, one free carboxyl group becomes a reaction point in the adhesive composition. By setting AV ２ to the lower limit value or more, when the polyester resin is made into an adhesive composition, it becomes easy to form a high crosslink density and the solder heat resistance of the adhesive composition can be improved. Also, by setting the upper limit value or less, it has the effect of making it easy to suppress gelation during the production of the polyester resin.

[0026] The acid value (AV １The crosslinking density is, for example, -5 to 450 eq / t, preferably 20 to 400 eq / t, more preferably 40 to 300 eq / t, even more preferably 60 to 200 eq / t, and even more preferably 80 to 150 eq / t. In the monoester form, two free carboxyl groups act as reaction sites in the adhesive composition. By keeping the crosslinking density within the above range, it becomes easier to form a high crosslink density, and the solder heat resistance of the adhesive composition can be improved.

[0027] Note that the acid value (AV) of the diester compound ２ ) and the acid value (AV) of the monoester compound １ The acid value (AV) can be measured directly, or if direct measurement is difficult, it can be calculated. For example, if the polycarboxylic acid component consists of dicarboxylic acid and tricarboxylic acid, it can be calculated based on the following formulas (A) to (D). First, let Xn be the tricarboxylic acid component contained in the polyester resin. First, the following formula (A) holds true for the acid value of the polyester resin. Acid value of polyester resin (AV) = Acid value of diester (AV) ２ ) + Acid value (AV) of the monoester compound １ ) + Acid value (AV) derived from dicarboxylic acid component ｄ ) + Acid value (AV) derived from unreacted Xn ｕ ) …(A) Next, focusing on the ester structure of the Xn component, the following equation (B) holds true. Content of Xn component (W) = Content of the triester of Xn (W) ３ ) + Content of the diester compound of Xn (W ２ ) + Content of the monoester compound of Xn (W １ ) + amount of unreacted Xn (W) ｕ ) …(B) Furthermore, since there is one free carboxyl group in one diester of Xn and two free carboxyl groups in one monoester of Xn, taking into account the molecular weight Mx of Xn, the following relationship (C) to (D) holds between the acid value and the content. Acid value of the diester (AV) ２ ) = 10 ６ × { (W ２ +W １ ) / 100} / Mx×{W ２ / (W ２ +W １)} ... (C) Acid value of monoester compound (AV １ ) = 10 ６ × { (W ２ +W １ ) / 100} / Mx×{W １ / (W ２ +W １ )} × 2 … (D) In ​​formula (A), AV can be determined, for example, by the method described in the embodiment. AV ｄ teeth １ The result obtained by 1H-NMR measurement, etc., is converted into an acid value per ton of sample. AV ｕ Similarly, the result obtained by HPLC analysis, etc., is converted to an acid value per ton of sample. In formula (B), W is １ H-NMR measurement, W ３ teeth １ This can be determined by H-NMR measurement and TOCSY spectral measurement, etc. ｕ This can be determined by HPLC analysis, etc. Then AV, AV ２ AV １ AV ｄ AV ｕ , W, W ３ , W ２ , W １ and W ｕ Of the 10 variables, 6 can be directly determined. For the 4 unknown variables, the four equations (A) to (D) hold true, and therefore AV can be determined using equations (A) to (D). ２ and AV １ This is calculated. AV ２ and AV １ When calculating these values, they may sometimes be calculated as negative. This is presumably due to the error contained in the measured values ​​used in the calculation, and negative values ​​are acceptable. In Xn, n represents the number of types of tricarboxylic acid; for example, if there is one type of tricarboxylic acid, then X １ If there are two or more types, then X １ , X ２ ...as AV for each component ２ and AV １ You should calculate the result and then sum it up.

[0028] In the polyester resin of the present invention, the molecular chain ends of the polyester may be carboxyl groups derived from the dicarboxylic acid component that constitutes the polyester main chain. The polyester resin of the present invention is also characterized by having a large amount of carboxyl groups derived from the dicarboxylic acid component, and the acid value (AV) of the carboxyl groups belonging to the dicarboxylic acid component that constitutes the polyester main chain is also a feature. ｄ The acid value (AV) is preferably 35 to 400 eq / t, more preferably 40 to 300 eq / t, even more preferably 45 to 200 eq / t, and even more preferably 50 to 100 eq / t. By keeping it within this range, the amount of tricarboxylic acid used can be reduced, which leads to the suppression of gelation during manufacturing. Furthermore, keeping it within this range also results in good thermal stability of the polyester resin. Acid value (AV) ｄ To adjust the value within the aforementioned range, it is desirable to perform, for example, the polycondensation reaction after the addition of tricarboxylic acid, as described later.

[0029] The acid value (AV) of the polyester resin of the present invention is 150 eq / t or higher, preferably 150 to 1000 eq / t, more preferably 180 to 1000 eq / t, more preferably 200 to 800 eq / t, and even more preferably 230 to 500 eq / t. Setting it above the lower limit increases the number of reaction sites with the epoxy resin described later, allowing for the formation of a tough adhesive layer with high crosslinking density after curing, making it easier to obtain an adhesive composition with excellent solder heat resistance. Setting it below the upper limit further improves adhesion and low dielectric properties.

[0030] In the polyester resin of the present invention, some of the tricarboxylic acid component may remain unreacted. If there is a large amount of unreacted tricarboxylic acid component, it may lead to poor curing or deterioration of storage stability when used in an adhesive composition, so it is preferable that the amount of unreacted tricarboxylic acid component be small. Specifically, the amount of unreacted tricarboxylic acid monomer in the polyester resin is preferably 1000 ppm or less, more preferably 900 ppm or less, and even more preferably 800 ppm or less. In practical terms, it may also be 50 ppm or more, 100 ppm or more, or 200 ppm or more (i.e., preferably 50 to 1000 ppm, preferably 100 to 900 ppm, more preferably 200 to 800 ppm). Furthermore, in the polyester resin of the present invention, the acid value (AV) derived from the unreacted tricarboxylic acid component is also important. ｕ The solvent concentration is preferably 1 to 200 eq / t, more preferably 3 to 100 eq / t, and even more preferably 5 to 50 eq / t. By keeping it within this range, a polyester resin with excellent solvent solubility is obtained, and the occurrence of haze in the varnish can be suppressed.

[0031] The polyester resin of the present invention has an IR spectral ratio of 0.030 or less, preferably 0.027 or less, more preferably 0.025 or less, and even more preferably 0.023 or less. The lower limit is not particularly limited, but practically it is 0.010 or more (i.e., preferably 0.010 to 0.030, more preferably 0.010 to 0.027, even more preferably 0.010 to 0.025, and even more preferably 0.010 to 0.023). If the upper limit is exceeded, the change in the reduced viscosity of the polyester resin when stored at Tg or above will be large, and the storage stability may deteriorate. The IR spectral ratio can be measured by the method described in the examples.

[0032] Furthermore, the polyester resin of the present invention may be copolymerized with a polycarboxylic acid component with a tetravalent or higher valency and / or a polyol component with a trivalent or higher valency. Examples of polycarboxylic acid components with a tetravalent or higher valency include aromatic carboxylic acids such as pyromellitic acid, benzophenonetetracarboxylic acid, pyromellitic anhydride (PMDA), and ethylene glycol bistrimellitate dianhydride, and aliphatic carboxylic acids such as 1,2,3,4-butanetetracarboxylic acid, which can be used alone or in combination of two or more. The polycarboxylic acid component with a tetravalent or higher valency is preferably 0 to 6 mol%, more preferably 0 to 3 mol%, even more preferably 0 to 1 mol%, and particularly preferably 0 to 0.5 mol% of 100 mol% of the polycarboxylic acid component of the polyester resin of the present invention. By keeping the amount below the upper limit, the generation of microgels and gelation of the resin can be prevented. In addition, thickening during the production of the polyester resin can be prevented, and molecular weight control can be easily achieved, enabling stable mass production. Examples of polyhydric alcohol components with a valency of 3 or higher include glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, α-methylglucose, mannitol, and sorbitol, which can be used individually or in combination of two or more.

[0033] The hydroxyl value (OHV) of the polyester resin of the present invention is preferably 5 to 70 eq / t, more preferably 10 to 60 eq / t, and even more preferably 15 to 50 eq / t. By keeping the hydroxyl value within this range, it becomes easier to form an adhesive composition with excellent dielectric properties when the polyester resin is used in an adhesive composition. Furthermore, if the hydroxyl value is within the above range, the number of reaction sites with the remaining tricarboxylic acid component (especially tricarboxylic acid anhydride) is reduced, and the hydroxyl groups and carboxyl groups are less likely to react during storage, thus suppressing the thickening of the polyester resin.

[0034] The reduced viscosity (ηsp / c) of the polyester resin of the present invention is 0.50 dl / g or higher, preferably 0.50 to 1.4 dl / g, more preferably 0.52 to 1.4 dl / g, more preferably 0.55 to 1.2 dl / g, and even more preferably 0.60 to 1.0 dl / g. Within this range, the inherent toughness of the polyester resin is exhibited, allowing it to withstand thermal expansion during soldering and suppressing blistering.

[0035] The number-average molecular weight (Mn) of the polyester resin of the present invention is preferably 1,000 to 50,000, more preferably 5,000 to 40,000, and even more preferably 9,000 to 30,000. Within this range, an adhesive composition can be obtained that is easy to handle when dissolved in a solvent and has excellent adhesive properties.

[0036] The weight-average molecular weight (Mw) of the polyester resin of the present invention is preferably 20,000 to 300,000, more preferably 30,000 to 200,000, even more preferably 40,000 to 150,000, and even more preferably 50,000 to 100,000. Within this range, an adhesive composition can be obtained that is easy to handle when dissolved in a solvent and has excellent adhesive properties.

[0037] The dispersion degree (Mw / Mn) of the polyester resin of the present invention is preferably 2.0 to 12.0, more preferably 3.0 to 9.0, and even more preferably 4.0 to 7.0. Within this range, an adhesive composition with excellent stability can be obtained.

[0038] The glass transition temperature (Tg) of the polyester resin of the present invention is preferably 0 to 80°C, more preferably 5 to 50°C, and even more preferably 10 to 35°C. Within this range, an adhesive composition with excellent adhesion can be obtained.

[0039] The polyester resin of the present invention can be produced by any known method that can produce a polycondensate of a polycarboxylic acid component and a polyhydric alcohol component, but it is preferable that the method includes, for example, 1) a step of esterifying the polycarboxylic acid component and the polyhydric alcohol component, 3) a step of reacting the reactant obtained in the above step with a tricarboxylic acid, and 4) a step of polycondensing the reactant obtained in the above step. By polycondensing after adding the tricarboxylic acid, it becomes easier to form not only a triester of the tricarboxylic acid, but also diesters and monoesters. This makes it possible to increase the acid value while suppressing the occurrence of gelation and increasing the molecular weight of the polyester resin produced, and makes it easier to control the IR spectral ratio to a desired range. After step 1), if necessary, step 2) a step of polycondensing the reactant obtained in step 1) may be performed. Each step will be described in detail below.

[0040] In step 1), an oligomer is produced by esterifying a polycarboxylic acid component with a polyhydric alcohol component. The polycarboxylic acid component and polyhydric alcohol component may be those mentioned above as appropriate.

[0041] In step 1), a polymerization catalyst can be used. Conventional known polymerization catalysts such as titanium compounds, antimony compounds, germanium compounds, and metal acetates can be used as polymerization catalysts. For example, titanium compounds can be tetra-n-butyl titanate, tetraisopropyl titanate, titanium oxyacetyl cetonate, etc., antimony compounds can be antimony trioxide, tributoxyantimony, etc., germanium compounds can be germanium oxide, tetra-n-butoxygermanium, etc., and metal acetates can be magnesium, iron, zinc, manganese, cobalt, aluminum, etc. These can be used individually or in combination of two or more. However, if the amount of antimony compound or zinc used as a polymerization catalyst increases, it may affect the reaction behavior and make it difficult to obtain a polyester resin with the desired properties, so it is desirable to use as little of these as possible. The content of antimony and zinc in the polyester resin is preferably 0 to 200 ppm, more preferably 0 to 100 ppm, even more preferably 0 to 50 ppm, even more preferably 0 to 1 ppm, and particularly preferably 0 ppm. The amount of metal derived from the polymerization catalyst in the polyester resin can be determined by the method described in the examples.

[0042] As the polymerization catalyst, at least a titanium compound is preferably used. When the total amount of metal derived from the polymerization catalyst in the polyester resin is 100% by mass, the titanium content is preferably 10 to 100% by mass, more preferably 30 to 100% by mass, even more preferably 50 to 100% by mass, and particularly preferably 80 to 100% by mass, and may also be 90 to 100% by mass. By setting it above the lower limit, better heat resistance for humidified soldering can be obtained. Furthermore, the titanium content in the polyester resin is preferably 5 ppm or more, more preferably 10 ppm or more, even more preferably 20 ppm or more, and particularly preferably 30 ppm or more. By setting it above the lower limit, better heat resistance for humidified soldering can be obtained.

[0043] The esterification reaction in step 1) is preferably carried out under heating. The reaction temperature is preferably 180 to 280°C, more preferably 200 to 260°C. The reaction time is preferably 1 to 10 hours, more preferably 2 to 8 hours.

[0044] In step 2), the reactant (oligomer) obtained in step 1) is polycondensed to produce a prepolymer. This step makes it easier to increase the molecular weight of the polyester resin finally obtained. The polycondensation reaction in step 2) is preferably carried out under heating, and the reaction temperature is preferably 180 to 280°C, more preferably 200 to 260°C. The reaction time is preferably 0.1 to 5 hours, more preferably 0.5 to 3 hours.

[0045] Step 2) is best carried out under vacuum or in an inert atmosphere (for example, in a nitrogen stream).

[0046] The hydroxyl value (OHV) of the prepolymer obtained after step 2) is preferably 200 to 500 eq / t, more preferably 220 to 400 eq / t, and even more preferably 250 to 350 eq / t. Keeping it within this range ensures a good balance with the carboxyl groups of the tricarboxylic acid used in the subsequent step 3). For example, if the hydroxyl groups of the prepolymer are in excess of the carboxyl groups of the tricarboxylic acid, the three carboxyl groups of the tricarboxylic acid will react, easily forming a triester, which may lead to gelation in subsequent steps. On the other hand, if the carboxyl groups of the tricarboxylic acid are in excess of the hydroxyl groups of the prepolymer, some of the tricarboxylic acid components are likely to remain unreacted, which may lead to poor curing or deterioration of storage stability when used in an adhesive composition.

[0047] The acid value (AV) of the prepolymer is preferably 0.5 to 50 eq / t, more preferably 1.0 to 30 eq / t, and even more preferably 2.0 to 20 eq / t. Within this range, the number of carboxyl groups does not increase excessively, making it easier to adjust the balance between the carboxyl groups and the hydroxyl groups of the prepolymer.

[0048] The reduced viscosity (ηsp / c) of the prepolymer is preferably 0.27 to 0.80 dl / g, more preferably 0.29 to 0.75 dl / g, and even more preferably 0.31 to 0.70 dl / g. Within this range, it is easier to adjust the hydroxyl value of the prepolymer to the desired range, and it is easier to increase the molecular weight of the final polyester.

[0049] The number-average molecular weight (Mn) of the prepolymer is preferably 1,000 to 20,000, more preferably 3,000 to 15,000, and even more preferably 5,000 to 10,000. When the Mn of the prepolymer is large, the number of terminal hydroxyl groups in the prepolymer decreases relatively, and the hydroxyl value of the prepolymer tends to decrease. Similarly, when the Mn of the prepolymer is small, the number of terminal hydroxyl groups in the prepolymer increases relatively, and the hydroxyl value of the prepolymer tends to increase. Within the above range, it is easy to adjust the hydroxyl value of the prepolymer to the desired range, and it is also easy to make the final polyester with a high molecular weight.

[0050] In step 3), a tricarboxylic acid adduct is produced by reacting the reactant (oligomer or prepolymer) obtained in the previous step with a tricarboxylic acid. By carrying out this step, triesters, diesters, and monoesters are more easily formed on the main chain of the polyester resin, making it easier to produce a polyester resin with high molecular weight and high acid value. The addition reaction in step 3) is preferably carried out under heating, and the reaction temperature is preferably 180 to 280°C, more preferably 200 to 260°C. The reaction time is preferably 0.1 to 4 hours, more preferably 0.5 to 3 hours.

[0051] The amount of tricarboxylic acid used in step 3) is preferably 2.0 mol or more, more preferably 2.5 to 10 mol, more preferably 3.0 to 9 mol, and even more preferably 3.5 to 8 mol, relative to 100 mol of the polycarboxylic acid component used in step 1). If the amount falls below the lower limit, it becomes difficult to increase the acid value of the polyester. If the amount exceeds the upper limit, the tricarboxylic acid component is more likely to remain unreacted.

[0052] In step 4), the reactant (tricarboxylic acid adduct) obtained in step 3) is polycondensed to produce a polyester resin. By carrying out this step, triesters, diesters, and monoesters are more readily formed in the main chain of the polyester resin, which is advantageous for producing a polyester resin with high molecular weight and high acid value. The polycondensation reaction in step 4) is preferably carried out under heating, and the reaction temperature is preferably 215 to 280°C, more preferably 225 to 260°C. The reaction time is preferably 0.1 to 5 hours, more preferably 0.5 to 3 hours.

[0053] Step 4) may be carried out under vacuum or in an inert atmosphere (for example, in a nitrogen stream). The polyester resin obtained in step 4) may then be removed and placed in a water bath or the like.

[0054] After step 4), if necessary, the polyester resin obtained in step 4) may be subjected to a water bath treatment in which it is immersed in water and stored for a certain period of time. When the content of unreacted tricarboxylic acid anhydride increases, the storage stability of the polyester resin tends to deteriorate. When unreacted tricarboxylic acid anhydride absorbs moisture, its carboxylic acid anhydride group opens up to become a carboxylic acid group, so this property can be utilized to promote the ring-opening reaction of the unreacted tricarboxylic acid anhydride by water bath treatment. The water temperature in the water bath treatment is preferably 0 to 50°C, more preferably 5 to 45°C, and even more preferably 10 to 40°C. The water bath treatment is preferably carried out for 4 days or more, more preferably 5 days or more, and even more preferably 6 days or more, and considering productivity, it is preferably 14 days or less, more preferably 12 days or less, and even more preferably 10 days or less (i.e., preferably 4 to 14 days, more preferably 5 to 12 days, and even more preferably 6 to 10 days).

[0055] <Adhesive Composition> The adhesive composition of the present invention contains the polyester resin described above. The polyester resin is preferably included as the main component in the adhesive composition. In this specification, the main component in the adhesive composition specifically refers to the component that is present in the highest amount in the solid content of the adhesive composition. The polyester resin content in the adhesive composition of the present invention is preferably 5 to 99.5% by mass, more preferably 20 to 99% by mass, even more preferably 30 to 98% by mass, even more preferably 40 to 97% by mass, and particularly preferably 50 to 96% by mass, based on 100% by mass of the solid content of the adhesive composition. Within the above range, good adhesion and heat resistance are obtained, which is preferable.

[0056] <Epoxy Resin> The adhesive composition of the present invention preferably contains an epoxy resin. The epoxy resin is not particularly limited as long as it has two or more glycidyl groups in its molecule. By using an epoxy resin, the carboxyl groups and glycidyl groups of the polyester resin react to form a crosslinked structure, which can improve the solder heat resistance and adhesive properties of the adhesive composition.

[0057] The epoxy resin is not particularly limited, but examples include biphenyl-type epoxy resins, naphthalene-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, novolac-type epoxy resins, alicyclic epoxy resins, dicyclopentadiene-type epoxy resins, glycidylamine-type epoxy resins, glycidyl ether-type epoxy resins, epoxy-modified polybutadiene, and glycidyl group-containing isocyanuric acid. These can be used individually or in combination of two or more types. Among these, novolac-type epoxy resins and glycidylamine-type epoxy resins are preferred in terms of solder heat resistance and low dielectric properties.

[0058] Novolac-type epoxy resins specifically refer to polyfunctional epoxy resins obtained by reacting novolac resins, which are reaction products of phenols and aldehydes, with epihalohydrins. Examples of novolac-type epoxy resins include "Epotote YDPN-638" from Nippon Steel Chemical Co., Ltd., "Epicote 152" and "Epicote 154" from Mitsubishi Chemical Corporation, "Epiclon N-740," "Epiclon N-770," "Epiclon N-775," "Epiclon N-660," "Epiclon N-665," "Epiclon N-670," "Epiclon N-673," and "Epiclon N-695" from DIC Corporation, "Epotote YDCN-700 series" from Nippon Steel Chemical Co., Ltd., and "EOCN-1020," "EOCN-102S," and "EOCN-104S" from Nippon Kayaku Co., Ltd.

[0059] A glycidylamine-type epoxy resin specifically refers to an epoxy resin that contains a glycidylamino group in which one or two glycidyl groups are bonded to an amino group within the molecule. Examples of glycidylamine-type epoxy resins include N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, triglycidyl para-aminophenol, 1,3-bis(diglycidylaminomethyl)cyclohexane, and N,N,N',N'-tetraglycidyl-m-xylenediamine, with N,N,N',N'-tetraglycidyl-m-xylenediamine being preferred.

[0060] The epoxy resin content is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, and even more preferably 1 to 10 parts by mass, per 100 parts by mass of polyester resin. A content above the lower limit provides sufficient curing effect and exhibits excellent adhesion and solder heat resistance. A content below the upper limit results in good low dielectric properties.

[0061] <Polycarbodiimide> The adhesive composition of the present invention may contain polycarbodiimide. The polycarbodiimide is not particularly limited as long as it has two or more carbodiimide bonds in its molecule. By using polycarbodiimide, the carboxyl groups of polyester resin or the epoxy groups of epoxy resin react with the carbodiimide bonds, improving heat resistance and adhesion.

[0062] In the adhesive composition of the present invention, the polycarbodiimide content is preferably 1 to 20 parts by mass, and more preferably 3 to 10 parts by mass, per 100 parts by mass of polyester resin. Setting the content above the lower limit can increase the crosslinking density, resulting in good solder heat resistance. Setting the content below the upper limit can achieve excellent solder heat resistance and low dielectric properties.

[0063] <Unsaturated Hydrocarbons> The adhesive composition of the present invention may contain unsaturated hydrocarbons having terminal unsaturated hydrocarbon groups and a 5% weight loss temperature of 260°C or higher. When unsaturated hydrocarbons are included, the presence of terminal unsaturated hydrocarbon groups increases the crosslinking density through a curing reaction caused by radicals generated by the use of radical generators, etc., thereby improving the solder heat resistance. Furthermore, since hydroxyl groups that worsen dielectric properties are not generated after the reaction, an adhesive with superior dielectric properties can be obtained. It is preferable that there be two or more terminal unsaturated hydrocarbon groups in one molecule, as this further increases the crosslinking density.

[0064] The 5% weight loss temperature of the unsaturated hydrocarbon must be 260°C or higher. Preferably, it is 270°C or higher, more preferably 280°C or higher, and even more preferably 290°C or higher. Having a 5% weight loss temperature above this value allows soldering to be performed without causing cosmetic defects even at temperatures exceeding the melting point of the solder. While there is no particular upper limit, 500°C is practical.

[0065] Unsaturated hydrocarbons preferably have an aromatic ring structure or an alicyclic structure as structural units. Having an aromatic ring structure or an alicyclic structure as structural units improves solder heat resistance and also provides excellent dielectric properties. In particular, it is preferable that the unsaturated hydrocarbon has an aromatic ring structure or an alicyclic structure as its backbone, and it is preferable that it is a polyphenylene ether or a cycloolefin polymer. Specific examples of polyphenylene ethers having terminal unsaturated hydrocarbon groups include SA-9000 from SABIC Corporation and OPE-2St from Mitsubishi Gas Chemical Company. Furthermore, cycloolefin polymers having terminal unsaturated hydrocarbon groups can be obtained by copolymerizing an olefin monomer having an unsaturated bond with an alicyclic olefin monomer.

[0066] The number-average molecular weight of the unsaturated hydrocarbon is preferably 500 to 100,000, more preferably 800 to 10,000, and even more preferably 1,000 to 5,000. Within this range, solubility in the solvent is good, and a uniform adhesive coating can be formed.

[0067] The unsaturated hydrocarbon content in the adhesive composition of the present invention is preferably 1 to 1,000 parts by mass, more preferably 2 to 500 parts by mass, even more preferably 3 to 200 parts by mass, and even more preferably 4 to 100 parts by mass, per 100 parts by mass of polyester resin. Within this range, excellent adhesion, compatibility with organic solvents, and solder heat resistance can be achieved simultaneously.

[0068] <Radical Generator> The adhesive composition of the present invention may contain a radical generator. Radicals generated by the radical generator efficiently react with terminal unsaturated hydrocarbon groups of unsaturated hydrocarbons, increasing the crosslinking density and thereby improving the solder's heat resistance and dielectric properties. The radical generator is not particularly limited, but it is preferable to use an organic peroxide. Examples of organic peroxides are not particularly limited, but include peroxides such as di-tert-butyl peroxyphthalate, tert-butyl hydroperoxide, dicumyl peroxide, benzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxypivalate, methyl ethyl ketone peroxide, di-tert-butyl peroxide, and lauroyl peroxide; and azonitriles such as azobisisobutyronitrile and azobisisopropionitrile.

[0069] The half-life temperature of the radical generator is preferably 140°C or higher. By setting the temperature to 140°C or higher, the radical reaction is prevented from starting when the solvent of the adhesive composition varnish is evaporated to produce the adhesive sheet, and excellent adhesion can be achieved.

[0070] The amount of the radical generating agent is preferably 0.1 to 50 parts by mass, and more preferably 1 to 10 parts by mass, per 100 parts by mass of unsaturated hydrocarbon. By keeping it within this range, an optimal crosslinking density can be achieved, and both adhesion and solder heat resistance can be attained.

[0071] <Organic Solvents> The adhesive composition of the present invention may further contain an organic solvent. The organic solvent used in the present invention is not particularly limited as long as it dissolves the polyester resin. When the adhesive composition of the present invention contains an organic solvent, it is desirable that the polyester resin is uniformly dissolved in the organic solvent.

[0072] Specifically, organic solvents include, for example, aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as hexane, heptane, octane, and decane; alicyclic hydrocarbons such as cyclohexane, cyclohexene, methylcyclohexane, and ethylcyclohexane; halogenated hydrocarbons such as trichloroethylene, dichloroethylene, chlorobenzene, and chloroform; alcoholic solvents such as methanol, ethanol, isopropyl alcohol, butanol, pentanol, hexanol, propanediol, and phenol; acetone, methyl isobutyl ketone, methyl ethyl ketone, pentanone, hexanone, cyclohexanone, isophorone, and acetophenone. Ketone solvents such as methyl cellsolve and ethyl cellsolve, ester solvents such as methyl acetate, ethyl acetate, butyl acetate, methyl propionate, and butyl formate, and glycol ether solvents such as ethylene glycol mono-n-butyl ether, ethylene glycol mono-iso-butyl ether, ethylene glycol mono-tert-butyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol mono-iso-butyl ether, triethylene glycol mono-n-butyl ether, and tetraethylene glycol mono-n-butyl ether can be used, and these can be used alone or in combination of two or more. Methyl ethyl ketone, methylcyclohexane, or toluene are particularly preferred due to their work environment and drying properties.

[0073] The amount of organic solvent is preferably in the range of 100 to 1000 parts by mass per 100 parts by mass of solid content of the adhesive composition. Setting it above the lower limit results in good liquidity and pot life. Setting it below the upper limit is advantageous in terms of manufacturing and transportation costs.

[0074] Furthermore, the adhesive composition of the present invention may contain other components as needed. Specific examples of such components include flame retardants, tackifiers, fillers, antioxidants, and silane coupling agents.

[0075] <Flame Retardants> Flame retardants may be added to the adhesive composition of the present invention as needed. Examples of flame retardants include bromine-based, phosphorus-based, nitrogen-based, and metal hydroxide compounds. Among these, phosphorus-based flame retardants are preferred, and phosphorus-based flame retardants such as phosphate esters, phosphate salts, and phosphine oxides can be used. These can be used alone or in combination of two or more types. When a flame retardant is included, it is preferable that the flame retardant be included in a range of 1 to 70% by mass of 100% by mass of the solid content of the adhesive composition, more preferably in a range of 5 to 60% by mass, and most preferably in a range of 10 to 50% by mass. By keeping it within the above range, flame retardancy can be achieved while maintaining adhesion, solder heat resistance, and electrical properties.

[0076] <Tackifiers> Tackifiers may be added to the adhesive composition of the present invention as needed. Examples of tackifiers include polyterpene resins, rosin resins, aliphatic petroleum resins, alicyclic petroleum resins, copolymer petroleum resins, styrene resins, and hydrogenated petroleum resins, and are used to improve adhesive strength. These can be used alone or in combination of two or more types. When tackifiers are included, it is preferable that they be included in an amount of 1 to 70% by mass, more preferably 5 to 60% by mass, and most preferably 10 to 50% by mass, based on 100% by mass of the solid content of the adhesive composition. By keeping the amount within the above range, the effect of the tackifier can be expressed while maintaining adhesion, solder heat resistance, and electrical properties.

[0077] <Fillers> Fillers may be added to the adhesive composition of the present invention as needed. Examples of organic fillers include powders of heat-resistant resins such as polyimide, polyamide-imide, fluororesin, and liquid crystal polyester. Examples of inorganic fillers include silica (SiO ２ ), alumina (Al ２ O ３ ), Titania (TiO ２ ), tantalum oxide (Ta ２ O ５ ), Zirconia (ZrO ２ ), silicon nitride (Si ３ N ４ ), boron nitride (BN), calcium carbonate (CaCO3) ３), calcium sulfate (CaSO4) ４ ), zinc oxide (ZnO), magnesium titanate (MgO・TiO ２ ), barium sulfate (BaSO ４ Examples include organic bentonite, clay, mica, aluminum hydroxide, and magnesium hydroxide, among which silica is preferred due to its ease of dispersion and its effect in improving heat resistance.

[0078] While hydrophobic and hydrophilic silica are generally known as silica, hydrophobic silica treated with dimethyldichlorosilane, hexamethyldisilazane, octylsilane, etc., is preferable here for imparting moisture resistance. When silica is incorporated, the amount is preferably 1 to 50% by mass, and more preferably 30 to 50% by mass, of the solid content of the adhesive composition. Increasing the amount above the lower limit can further enhance heat resistance. Conversely, keeping the amount below the upper limit prevents poor silica dispersion and excessively high solution viscosity, resulting in good workability.

[0079] <Antioxidant> The adhesive composition of the present invention may optionally contain an antioxidant. The inclusion of an antioxidant is preferable because it can suppress the deterioration of properties such as adhesion and dielectric properties even when used in high-temperature environments exposed to air. The antioxidant is not particularly limited, but examples include phenolic antioxidants, amine antioxidants, phosphorus antioxidants, and sulfur antioxidants. These may be used individually or in combination of two or more.

[0080] If the adhesive composition contains an antioxidant, its content is preferably 0.5 to 5 parts by mass, and more preferably 1 to 3 parts by mass, per 100 parts by mass of solid content of the adhesive composition. If the antioxidant content is within the above range, it is possible to suppress the deterioration of properties such as adhesion and dielectric properties even when used in a high-temperature environment exposed to air.

[0081] <Silane Coupling Agent> A silane coupling agent may be added to the adhesive composition of the present invention as needed. Adding a silane coupling agent is highly preferable because it improves the adhesion to metals and heat resistance properties. The silane coupling agent is not particularly limited, but examples include those having an unsaturated group, an epoxy group, or an amino group. Of these, silane coupling agents having an epoxy group, such as γ-glycidoxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltriethoxysilane, are even more preferable from the viewpoint of heat resistance. When a silane coupling agent is added, the amount added is preferably 0.5 to 20% by mass of the solid content of the adhesive composition. By keeping it within this range, the heat resistance and adhesion of the solder can be improved.

[0082] <Laminate> In the present invention, a laminate is a substrate on which the adhesive composition of the present invention is laminated. Specifically, it is a substrate on which the adhesive composition is laminated (a two-layer laminate of substrate / adhesive layer), or a further laminate of substrates (a three-layer laminate of substrate / adhesive layer / substrate). Here, the adhesive layer refers to the layer of adhesive composition obtained after applying the adhesive composition of the present invention to a substrate and drying it. The laminate of the present invention can be obtained by applying the adhesive composition of the present invention to various substrates in accordance with conventional methods, drying it, and further laminating other substrates.

[0083] The laminates of the present invention include laminates in which the adhesive composition of the present invention is laminated onto a substrate which is a resin substrate, a metal substrate, paper, or an inorganic non-metallic substrate as described later, and laminates (adhesive sheets) in which the adhesive composition of the present invention is laminated onto a release substrate. Examples of the laminates of the present invention include copper-clad laminates (CCLs), resin-coated metal foils, coverlay films, bonding sheets, and the like.

[0084] <Substrate> The substrate in this invention is not particularly limited as long as it can be coated with the adhesive composition of the present invention, dried, and form an adhesive layer. Examples include resin substrates such as film-like resins, metal substrates such as metal plates and metal foils, papers, inorganic non-metallic substrates, and release substrates.

[0085] Examples of materials for the resin substrate include epoxy resin, polyester resin, polyamide resin, aramid resin, polyimide resin, polyamide-imide resin, liquid crystal polymer, polyphenylene sulfide, polyphenylene ether, polyethersulfone, polyetheretherketone, polycarbonate, polyarylate, syndiotactic polystyrene, polyolefin resin, fluororesin, and the like. The form of the resin substrate is not particularly limited, but examples include films made from the resin and glass cloth (FR-4) impregnated with the resin. The resin may contain fillers such as silica.

[0086] Any conventionally known conductive material usable for circuit boards can be used as the metal substrate. Examples of materials include various metals such as SUS, copper, aluminum, iron, steel, zinc, nickel, and their alloys, plated products, and metals treated with other metals such as zinc or chromium compounds. Preferably, it is a metal foil, and more preferably, it is a copper foil. There are no particular limitations on the thickness of the metal foil, but it is preferably 1 to 50 μm, more preferably 3 to 30 μm, and even more preferably 10 to 20 μm. If the thickness is too thin, it may be difficult to obtain sufficient electrical performance of the circuit, while if the thickness is too thick, the processing efficiency during circuit fabrication may decrease. Metal foil is usually provided in roll form. The form of the metal foil used when manufacturing the printed circuit board of the present invention is not particularly limited. When using a ribbon-shaped metal foil, its length is not particularly limited. Its width is also not particularly limited, but it is preferably about 250 to 500 cm. The surface roughness of the substrate is not particularly limited, but is preferably 0.1 to 3 μm, more preferably 0.2 to 2 μm, and even more preferably 0.3 to 1.5 μm.

[0087] Examples of paper types include high-quality paper, kraft paper, roll paper, and glassine paper.

[0088] Examples of inorganic non-metallic substrates include glass and ceramics.

[0089] The release substrate is not particularly limited, but examples include paper such as fine paper, kraft paper, roll paper, and glassine paper, on which layers of a sealant such as clay, polyethylene, or polypropylene are applied, and then a silicone-based, fluorine-based, or alkyd-based release agent is applied on each of these layers. Other examples include various olefin films such as polyethylene, polypropylene, ethylene-α-olefin copolymer, and propylene-α-olefin copolymer, applied alone, and films such as polyethylene terephthalate on which the release agent is applied.

[0090] In the present invention, the method for coating the adhesive composition onto a substrate is not particularly limited, but examples include a comma coater, a reverse roll coater, a die coater, etc. Alternatively, if necessary, the adhesive layer can be applied directly or by transfer to the rolled copper foil, which is a component material of the printed circuit board, or to the resin substrate. The thickness of the adhesive layer after drying can be changed as needed, but is preferably in the range of 5 to 200 μm. Sufficient adhesive strength can be obtained by setting it to be above the lower limit of the adhesive film thickness. Also, setting it to be below the upper limit makes it easier to control the amount of residual solvent in the drying process, and blistering is less likely to occur when pressing the printed circuit board. The drying conditions are not particularly limited, but the residual solvent rate after drying is preferably 1% by mass or less. Setting it to 1% by mass or less suppresses foaming of the residual solvent when pressing the printed circuit board, and blistering is less likely to occur.

[0091] <Copper-clad laminate (CCL)> In the present invention, a copper-clad laminate (CCL) is a laminate in which the metal foil is laminated on one or both sides of the resin substrate. The resin substrate and the metal foil may be laminated via the adhesive composition of the present invention, or they may be laminated by thermocompression bonding without the adhesive composition of the present invention. Specific configurations of the copper-clad laminate (CCL) include a metal foil layer / adhesive layer / resin substrate layer / adhesive layer / metal foil layer, etc. By etching the metal foil layer to form a circuit pattern, it can be used as a laminate material for printed wiring boards.

[0092] <Resin-Coated Metal Foil> In the present invention, resin-coated metal foil refers to a metal foil on which an adhesive layer, which is a cured product of the adhesive composition of the present invention, is laminated on one side. Specific configurations include a metal foil layer / adhesive layer or a metal foil layer / adhesive layer / release substrate. The metal foil is preferably copper foil. Since the adhesive layer in the resin-coated metal foil can be laminated with the resin substrate, the resin-coated metal foil can be used as a material when manufacturing the CCL.

[0093] <Coverlay Film> In the present invention, a coverlay film is obtained by laminating the resin substrate and the release substrate via the adhesive composition of the present invention. As the resin substrate in the coverlay film, any conventionally known insulating film for printed circuit boards can be used. Preferred resins for the resin substrate include polyester resin, aramid resin, polyimide resin, polyamide-imide resin, liquid crystal polymer, polyphenylene sulfide, polyethersulfone, polyetheretherketone, polycarbonate, polyarylate, syndiotactic polystyrene, and polyolefin resins, with films composed of polyimide resin, liquid crystal polymer, and fluororesin being more preferred. The coverlay film can be manufactured by coating the resin substrate with the adhesive composition of the present invention, drying it, and then laminating the release substrate on top of it.

[0094] <Bonding Sheet> In the present invention, a bonding sheet is a sheet on which the adhesive composition of the present invention is laminated onto the release substrate. Specific configurations include release substrate / adhesive layer / release substrate, or release substrate / adhesive layer / substrate (excluding the release substrate) / adhesive layer / release substrate, etc. The laminated release substrate functions as a protective layer for the substrate. Furthermore, by using the release substrate, the release substrate can be peeled off the bonding sheet and used for bonding between other substrates. As for the release substrate in the bonding sheet, from the viewpoint of visibility during the manufacture of printed circuit boards, it is preferable that at least one side of the release substrate laminated on the outermost layer of the bonding sheet is opaque.

[0095] <Printed Wiring Boards> The adhesive composition of the present invention is preferably used for printed wiring boards. The printed wiring board in the present invention includes a laminate as a component having a metal substrate (metal foil) that forms a conductive circuit and a resin substrate. The printed wiring board in the present invention is a general term for so-called rigid substrates, flexible printed circuit boards (FPCs), flat cables, circuit boards for automated tape bonding (TAB), etc.

[0096] The printed circuit board of the present invention can have any laminate configuration that can be used as a printed circuit board. Preferably, the printed circuit board of the present invention includes a laminate as a component, in which the adhesive composition of the present invention is laminated on a substrate which is a resin substrate, a metal substrate, paper, or an inorganic non-metallic substrate. If necessary, a configuration in which two or more of the above printed circuit boards are laminated can be used. Also, if necessary, a configuration in which two or three or more bonding sheets are laminated on top of the protective layer of the printed circuit board, and a protective layer such as a coverlay film or solder resist is provided thereon. For example, using the laminate such as CCL, a printed circuit board can be made consisting of four layers such as a resin substrate layer / adhesive layer / metal foil layer / coverlay film layer, or a resin substrate layer / metal foil layer / adhesive layer / coverlay film layer. Alternatively, a printed circuit board can be made consisting of five layers: a resin substrate layer / adhesive layer / metal foil layer / adhesive layer / coverlay film layer.

[0097] Circuit formation on a metal substrate (metal foil layer) can be carried out using conventionally known methods. An additive method or a subtractive method may be used. Preferably, a subtractive method is used.

[0098] The printed circuit board of the present invention can be manufactured using any conventionally known process, except for using the materials of each layer described above. For example, a circuit pattern can be formed on a three-layer CCL with adhesive or a two-layer CCL without adhesive, and then laminated by bonding it with another CCL using a bonding sheet or prepreg and heat curing. After that, a multilayer printed circuit board can be obtained by performing processes such as drilling, through-hole plating, and copper foil pattern formation, followed by forming a protective layer such as a coverlay film or solder resist on the outermost layer and then performing further surface treatment.

[0099] The adhesive composition of the present invention can be suitably used in the manufacture of printed circuit boards, and specifically in each adhesive layer of a printed circuit board. Furthermore, because it has high adhesion to low-polarity resin substrates such as liquid crystal polymers, polyphenylene sulfide, syndiotactic polystyrene, and polyolefin resins, solder reflow resistance can be obtained. The adhesive layer itself also has excellent low dielectric properties, making it possible to produce a printed circuit board with excellent high-frequency characteristics.

[0100] <Laminated Film for Decorating Three-Dimensional Molded Products> The "laminated film for decorating three-dimensional molded products" in this invention is a film used in decorative molding of three-dimensional molded products. That is, a film with design properties is adhered to various molded bodies to impart design properties or surface protection functions to the molded bodies. In doing so, the film is deformed to conform to the surface of the three-dimensional shape and adheres tightly to it.

[0101] The adhesive composition of the present invention can be suitably used as an adhesive for laminated films used to decorate three-dimensional molded products. That is, the laminated film used to decorate three-dimensional molded products can include a layer formed from the adhesive composition of the present invention as a constituent element. The adhesive composition of the present invention has high adhesion to conventional resin substrates such as flexible polyvinyl chloride film, polycarbonate film, polyester film, and ABS that constitute the laminated film used to decorate three-dimensional molded products, and also has excellent sheet life. Therefore, the adhesive composition of the present invention is suitable as an adhesive composition for use in laminated films used to decorate three-dimensional molded products, such as automotive exterior components such as side under skirts, side garnishes, and door mirrors, automotive interior components such as instrument panels and door switch panels, and housings for home appliances such as refrigerators, mobile phones, and lighting fixtures.

[0102] <Film for Metal Can Lamination> The adhesive composition of the present invention can be suitably used as an adhesive for metal can lamination films. That is, a metal can lamination film can include a layer formed from the adhesive composition of the present invention as a constituent element. The adhesive composition of the present invention has high adhesion to conventional polyester films that constitute metal can lamination films and to metal substrates such as tinplate, tin-free steel, and aluminum that constitute metal cans, and also has excellent pot life. For this reason, the adhesive composition of the present invention is suitable as an adhesive composition to be used in each adhesive layer of a metal can lamination film.

[0103] <Packaging Materials> The adhesive composition of the present invention can be suitably used as an adhesive for packaging materials. That is, packaging materials can include layers formed from the adhesive composition of the present invention as constituent elements. The adhesive composition of the present invention has high adhesion to plastic films such as polyethylene terephthalate, polyethylene naphthalate, polyvinyl chloride resin, ABS resin, acrylic resin, and polycarbonate resin, which are commonly used in packaging materials, as well as gas barrier substrates such as aluminum foil, and also exhibits excellent pot life. Therefore, the adhesive composition of the present invention is suitable as an adhesive composition to be used in each adhesive layer of packaging materials.

[0104] This application claims the benefit of priority based on Japanese Patent Application No. 2024-171167, filed on 30 September 2024. The entire specification of Japanese Patent Application No. 2024-171167, filed on 30 September 2024, is incorporated herein by reference.

[0105] The present invention will be described in more detail below with reference to examples, but the present invention is not limited by the following examples, and it is certainly possible to implement it with appropriate modifications within the scope that is consistent with the spirit of the preceding and following descriptions, and all such modifications are included within the technical scope of the present invention. In the following, unless otherwise specified, "parts" means "parts by mass" and "%" means "percent mass".

[0106] <Evaluation of prepolymers and polyester resins> (1) The resin composition samples were alkaline-decomposed with sodium hydroxide in a mixed solvent of deuterium methanol / dimethyl sulfoxide-d6, and the decomposition solution was diluted with heavy water. Nuclear magnetic resonance (NMR) spectrometer (Bruker "AVANCE NEO 600") and data processing were performed using Bruker TopSpin® 4.0 software. １ ¹H-NMR measurements were performed. The measurements were conducted under the following conditions: resonance frequency of 600 MHz, waiting time of 1 sec, number of integrations of 64, measurement temperature of 303 K, and a reference level of heavy water at 4.74 ppm. The resin composition was calculated in moles from the integral ratio. The integral value of the terephthalic acid peak detected at 7.89 ppm was set to 100. Note that even if the monomer is not terephthalic acid (for example, isophthalic acid or orthophthalic acid), if the position of the proton peak in NMR is clear, it can be used as a reference for the resin composition, and in that case, the integral value of the proton peak of that monomer can be set to 100. The same applies to the "content of TMA triester compounds" described later.

[0107] (2) Reduced viscosity (ηsp / c) 0.1 g of the sample was dissolved in 25 ml of a mixed solvent of phenol / tetrachloroethane (weight ratio 6 / 4), and measured at 30°C using an Ubbelohde viscometer.

[0108] (3) The GPC sample was dissolved or diluted in tetrahydrofuran to a sample concentration of approximately 0.5%, and filtered through a polytetrafluoroethylene membrane filter with a pore size of 0.5 μm to be used as the measurement sample. The number-average molecular weight (Mn) and weight-average molecular weight (Mw) of the sample were measured by gel permeation chromatography using tetrahydrofuran as the mobile phase and a differential refractometer as the detector, and the degree of dispersion (Mw / Mn) was calculated. The flow rate was 1 mL / min and the column temperature was 30°C. Showa Denko "KF-802", "KF-804L", and "KF-806L" columns were used. Monodisperse polystyrene was used as the molecular weight standard.

[0109] (4) Hydroxyl Value (OHV) The sample was dissolved in chloroform-d alone and in a mixed solvent of chloroform-d and trifluoroacetic acid, and nuclear magnetic resonance (NMR) was performed using a Bruker AVANCE NEO 600 and Bruker TopSpin® 4.0 software for data processing, using each solvent. １ ¹H-NMR measurements were performed, the integral values ​​were determined, and the hydroxyl value was calculated by averaging these values.

[0110] (5) Glass transition temperature (Tg) was measured using a differential scanning calorimeter (SII "DSC-200"). 5 mg of the sample was placed in an aluminum container with a retaining lid and sealed. It was cooled to -50°C using liquid nitrogen, and then heated to 150°C at a rate of 20°C / min. In the endothermic curve obtained during this process, the temperature at the intersection of the baseline before the endothermic peak and the tangent line toward the endothermic peak was defined as the glass transition temperature.

[0111] (6) Amount of unreacted TMA: 160 mg of the sample was dissolved in chloroform, then low-moisture methanol was added and allowed to stand for 36 hours to methylate the anhydrous ring. The supernatant was filtered through a PTFE filter, and the dried residue was dissolved in DMAc. The sample was analyzed using a Shimadzu HPLC to identify the amount of unreacted TMA in the polyester resin. Column: Inertsil ODS-2 5 μm 4.0 mm × 250 mm Mobile phase: A 0.4% phosphoric acid, B acetonitrile Flow rate: 1.0 mL / min Injection volume: 10 μL Detection wavelength: 258 nm

[0112] (7) Samples containing the triester compound of TMA were dissolved in a mixed solvent of chloroform-d / 1,1,1,3,3,3-Hexafluoro-2-propanol-d2 / triethylamine (90 / 10 / 1), and nuclear magnetic resonance (NMR) was performed using a Bruker AVANCE NEO 600 spectrometer and Bruker TopSpin® 4.0 software for data processing. １ 1H-NMR and TOCSY spectral measurements were performed. １ The 1H-NMR measurements were performed under the following conditions: resonance frequency of 600.13 MHz, waiting time of 1 sec, number of integrations of 64, measurement temperature of 303 K, and reference level of chloroform at 7.33 ppm. １ When the integral value of TPA detected at 8.12 ppm in 1H-NMR was set to 100, the integral value of the peak detected at 7.75 to 7.85 ppm was defined as Hc. Measurement by the TOCSY method was performed under the following conditions: resonance frequency 600.13 MHz, waiting time 2 sec, pulse width 2.5 msec, mixing time 0.05 sec, number of integrations 16 times, measurement temperature 303 K, and reference chloroform 7.3 ppm. The integral values ​​of the peaks observed at (F1 axis, F2 axis) = (7.8, 8.2) and (7.8, 8.1) in the TOCSY spectrum were defined as Ha and Hb, respectively, and X was calculated using the following formula with (1) composition mol ratio of terephthalic acid obtained from the resin composition: Hd. Hc is the integral value including components derived from the triester of TMA. By measuring using the TOCSY method, the Hc component is separated into Ha and Hb, and Ha is the integral value containing only the triester. X = Hd / 100 × 4 × Hc × (Ha / (Ha + Hb)) Let X be the content (mol%) of the triester of TMA.

[0113] (8) Acid value (AV) 0.2 g of the sample was dissolved in 20 ml of chloroform and titrated with a methanol solution of 0.1 N sodium methoxide in the presence of phenolphthalein indicator. The point at which the solution turned red was defined as the neutralization point, and the value was converted to the equivalent amount per ton of sample (eq / t).

[0114] The acid value sample derived from the dicarboxylic acid component was dissolved in a mixed solvent of chloroform-d / 1,1,1,3,3,3-hexafluoro-2-propanol-d2 / triethylamine, and using a nuclear magnetic resonance apparatus (NMR) ("AVANCE NEO 600" manufactured by Bruker) and Bruker TopSpin (registered trademark) 4.0 software for data processing, １ 1H-NMR measurement was carried out, the content derived from the dicarboxylic acid component was determined from the integral value, and it was converted to the acid value per ton of the sample.

[0115] (10) Since it is difficult to directly measure the acid value (AV ２ ) of the diester form and the acid value (AV １ ) of the monoester form, the acid value (AV ２ ) and the acid value (AV １ ) were determined from the following formulas (A) to (D). First, the following formula (A) holds for the acid value of the polyester resin. Acid value of polyester resin (AV) = Acid value of the diester form of TMA (AV ２ ) + Acid value of the monoester form of TMA (AV １ ) + Acid value derived from the dicarboxylic acid component (AV[[ID=ID=18]] ｄ ) + Acid value derived from unreacted TMA (AV ｕ )... (A) Next, focusing on the ester structure of the TMA component, the following formula (B) holds. Content of TMA component (W) = Content of the triester form of TMA (W ３ ) + Content of the diester form of TMA (W ２ ) + Content of the monoester form of TMA (W １ ) + Amount of unreacted TMA (W ｕ )... (B) Also, since there is 1 free carboxy group in one diester form of TMA and 2 free carboxy groups in one monoester form of TMA, taking into account the molecular weight of TMA of 192.13, the following relationships of formulas (C) to (D) hold between the acid value and the content. Acid value of the diester form (AV ２ ) = 10 ６ × { (W ２ + W １ ) / 100} / 192.13 × { W ２ / (W ２ + W１ )} ... (C) Acid value of monoester compound (AV １ ) = 10 ６ × { (W ２ +W １ ) / 100} / 192.13×{W １ / (W ２ +W １ )}×2...(D) In ​​formula (A), AV and AV ｄ The measurement results mentioned above will be used, AV ｕ The result of "(6) Amount of unreacted TMA" shall be converted to the acid value per ton of sample. The units for these are eq / t. In formula (B), W ３ (7) Content of TMA triester compounds, W ｕ The result of "(6) Amount of unreacted TMA" will be used for W, and the total amount of TMA components obtained in "(1) Resin composition" will be used for W. Note that these units should be consistent. Then AV, AV ２ AV １ AV ｄ AV ｕ , W, W ３ , W ２ , W １ and W ｕ Of the 10 variables, 6 can be directly determined. For the 4 unknown variables, the four equations (A) to (D) hold true, and therefore AV can be determined using equations (A) to (D). ２ and AV １ This is calculated.

[0116] (11) Amount of Metal Components The amount of metal components contained in the polyester resin was determined based on the following procedure. The polyester resin was weighed into a platinum crucible, carbonized on an electric stove, and then ashed in a muffle furnace at 550°C for 8 hours. The ashed sample was dissolved in 1.2 M hydrochloric acid to prepare the sample solution. The prepared sample solution was measured under the following conditions, and the concentrations of antimony, titanium, and zinc in the polyester resin were determined by high-frequency inductively coupled plasma emission spectrometry. Apparatus: SPECTRO CIROS-120 Plasma output: 1400 W Plasma gas: 13.0 L / min Auxiliary gas: 2.0 L / min Nebulizer: Cross-flow nebulizer Chamber: Cyclone chamber Measurement wavelength: 167.078 nm

[0117] (12) Using an IR spectral ratio Fourier transform infrared spectrophotometer (Agilent Technologies "Cary 660 FTIR"), the spectrum of the obtained polyester resin was measured at 1715 cm⁻¹. －１ The peak absorbance intensity I (1715) and 1785 cm⁻¹ are shown. －１ The peak absorbance intensity I(1785) was determined, and the IR spectral ratio was calculated using I(1785) / I(1715). The measurement conditions were as follows: Light source: Ceramic Detector: TGS Beam splitter: KBr Measurement method: ATR method (diamond crystal, incident angle 45°) Measurement wavenumber range: 700-4000 cm －１ Resolution: 8cm －１ Number of calculations: 16 Analysis software: Resolutions Pro

[0118] (13) Storage Stability: Polyester resin was stored in a constant temperature room set at 25°C for one month, and the change in reduced viscosity was determined. A judgment of ◎, ○, △, or × was made based on the evaluation criteria below. The change in reduced viscosity (%) is the same as the reduced viscosity η of the polyester resin before storage. ０ , the reduced viscosity of polyester resin after storage η １ When this is the case, {(η ０ -η １ ) / η ０The result was calculated using the formula: (} × 100). ◎: Within ±5% ○: Over ±5% and within ±8% △: Over ±8% and within ±10% ×: Outside the above range

[0119] <Example 1> In a 3 L four-necked flask, 201 parts terephthalic acid, 479 parts isophthalic acid, 189 parts 2-methyl-1,3-propanediol, 372 parts 1,6-hexanediol, and 0.4 parts tetra-n-butyl titanate were charged. The temperature was then gradually increased to 250°C over 4 hours to carry out the esterification reaction. After that, while maintaining the temperature at 250°C, the pressure was reduced to 10 mmHg over 30 minutes to carry out initial polymerization, and then the pressure was reduced to below 1 mmHg for 90 minutes to carry out final polymerization, thereby polymerizing the prepolymer. After that, the vacuum was broken and the prepolymer was removed and its physical properties were evaluated. Next, 39 parts trimellitic anhydride (TMA) was added under a nitrogen atmosphere at 240-250°C and stirred for 60 minutes. Then, the pressure was reduced again to below 1 mmHg and polymerization was carried out at 250°C for 60 minutes. After that, the vacuum was broken and stirred under a nitrogen atmosphere for 1 hour. Subsequently, the material was removed and placed in a water bath to obtain polyester resin. The obtained resin was then stored immersed in water at 25°C for one week before being removed to obtain polyester resin. The composition and various properties of the final obtained polyester resin are shown in Table 1.

[0120] 160 parts of the obtained polyester resin and 240 parts of methyl ethyl ketone were charged into a 1 L flask. The mixture was heated to 40°C and stirred for 5 hours until completely dissolved. After confirming dissolution, the mixture was removed to obtain polyester varnish. To 100 parts of the solids content of the polyester varnish, 9 parts of YDCN-700-10 (novolac-type epoxy resin) manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd. and 0.1 parts of TETRAD®-X (N,N,N',N'-tetraglycidyl-m-xylenediamine) manufactured by Mitsubishi Gas Chemical Co., Ltd. were added as epoxy resins. The solids content was then adjusted to 35% using methyl ethyl ketone to obtain an adhesive composition.

[0121] <Example 2> In Example 2, a polyester resin was obtained in the same manner as in Example 1, except that the amount of TMA added was increased compared to Example 1. Although the amount of TMA added was increased, gelation did not occur during manufacturing, and a polyester resin with excellent storage stability was obtained in Example 2 as well.

[0122] <Example 3> In Example 3, a polyester resin was obtained in the same manner as in Example 1, except that the polycarboxylic acid was changed to 335 parts terephthalic acid, 134 parts isophthalic acid, and 245 parts sebacic acid, and the polyhydric alcohol was changed to 211 parts ethylene glycol and 246 parts neopentyl glycol. In Example 3, although an aliphatic dicarboxylic acid was copolymerized as the dicarboxylic acid component, the IR spectral ratio was within the desired range, and a polyester resin with excellent storage stability was obtained in Example 3 as well.

[0123] <Comparative Example 1> In Comparative Example 1, the polyester resin was obtained in the same manner as in Example 1, except that the manufactured polyester resin was not immersed in water. Because it was not immersed in water, the ring-opening of the unreacted TMA was insufficient, and the IR spectral ratio remained high. As a result, the storage stability was poor.

[0124] <Comparative Example 2> In Comparative Example 2, polyester resin was obtained in the same manner as in Example 1, except that the manufactured polyester resin was immersed in water and stored at 25°C for 3 days before being removed. Because the immersion period in water was short, the ring-opening of the unreacted TMA was insufficient, and the IR spectral ratio remained high. As a result, the storage stability was poor.

[0125] <Comparative Example 3> In Comparative Example 3, the polyester resin was obtained in the same manner as in Example 3, except that the manufactured polyester resin was not immersed in water. Because it was not immersed in water, the ring-opening of the unreacted TMA was insufficient, and the IR spectral ratio remained high. As a result, the storage stability was poor.

[0126] <Comparative Example 4> In a 3 L four-necked flask, 201 parts terephthalic acid, 466 parts isophthalic acid, 4 parts TMA, 189 parts 2-methyl-1,3-propanediol, 372 parts 1,6-hexanediol, and 0.4 parts tetra-n-butyl titanate were charged. The temperature was then gradually increased to 250°C over 4 hours to carry out the esterification reaction. After that, while maintaining the temperature at 250°C, the pressure was reduced to 10 mmHg over 30 minutes to carry out initial polymerization, and then the pressure was reduced to below 1 mmHg for 90 minutes to carry out final polymerization, thereby polymerizing the prepolymer. When the reduced viscosity of the prepolymer reached 0.56 dl / g, the vacuum was broken and the prepolymer was removed and its physical properties were evaluated. Next, 23 parts TMA was added under a nitrogen atmosphere at 230°C and stirred for 60 minutes. After that, it was removed into a water bath to obtain a polyester resin. The obtained resin was then stored immersed in water at 25°C for one week before being removed to obtain polyester resin. Because a polycondensation reaction was not carried out after TMA addition, a large amount of unreacted TMA remained, and even after immersion in water, the acid anhydride was not consumed, resulting in a high IR spectral ratio. Consequently, the storage stability was poor.

[0127]

[0128] In Table 1, abbreviations are used with the following meanings. Also in Table 1, the unit "mol / T.A" represents the amount (mol) of TMA used in the acid addition reaction relative to 100 mol of polycarboxylic acid component charged in the esterification reaction. "TPA": Terephthalic acid "IPA": Isophthalic acid "TMA": Trimellitus anhydride "SA": Sebacic acid "EG": Ethylene glycol "NPG": Neopentyl glycol "2MG": 2-methyl-1,3-propanediol "HD": 1,6-Hexanediol "Ti": Titanium

[0129] The polyester resin of the present invention exhibits excellent storage stability and high reducing viscosity while being capable of forming a high crosslink density. The adhesive composition containing the polyester resin of the present invention is useful as an adhesive composition for printed circuit boards, as well as as an adhesive sheet, laminate, and printed circuit board containing the same.

Claims

1. The polyester resin contains 2.0 mol% or more of tricarboxylic acid components out of 100 mol% of total polycarboxylic acid components, has a reduced viscosity of 0.50 dl / g or more, has an acid value (AV) of 150 eq / t or more, and has an acid value of 1715 cm² measured by Fourier transform infrared absorption spectroscopy (FTIR). －１ The peak absorbance intensity I (1715) and 1785 cm⁻¹ are shown. －１ A polyester resin characterized in that the ratio of peak absorbance intensities I(1785) to I(1715), I(1785) / I(1715), is 0.030 or less.

2. The polyester resin according to claim 1, wherein the amount of unreacted tricarboxylic acid monomer is 1000 ppm or less.

3. The polyester resin according to claim 1, wherein the content of a tricarboxylic acid component in which three carboxyl groups form an ester bond is 2.0 mol% or less relative to the total amount of polycarboxylic acids constituting the polyester resin.

4. The polyester resin according to claim 1, wherein the content of antimony and zinc in the polyester resin is 200 ppm or less.

5. The polyester resin according to claim 1, comprising one or more dicarboxylic acid components selected from the group consisting of aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and aromatic dicarboxylic acids as the dicarboxylic acid component constituting the polyester resin.

6. The polyester resin according to claim 1, wherein the hydroxyl value (OHV) is 5 to 70 eq / t.

7. The polyester resin according to claim 1, wherein the glass transition temperature (Tg) is 0 to 80°C.

8. The polyester resin according to claim 1, wherein the weight-average molecular weight (Mw) is 20,000 to 300,000.

9. The polyester resin according to claim 1, wherein the polycarboxylic acid component with tetravalent or higher is present in 100 mol% of the polycarboxylic acid component, and the amount of this polycarboxylic acid component is 6 mol% or less.

10. An adhesive composition comprising the polyester resin according to any one of claims 1 to 9.

11. The adhesive composition according to claim 10, which is for printed circuit boards.

12. An adhesive sheet in which the adhesive composition according to claim 10 is laminated on a release substrate.

13. A laminate in which the adhesive composition according to claim 10 is laminated onto a substrate which is a resin substrate, a metal substrate, paper, or an inorganic nonmetallic substrate.

14. A printed circuit board comprising the laminate described in claim 13 as a component.

15. A laminated film for decorating three-dimensional molded articles, comprising a layer formed from the adhesive composition described in claim 10 as a constituent element.

16. A film for laminating metal cans, comprising a layer formed from the adhesive composition described in claim 10 as a component.

17. A packaging material comprising a layer formed from the adhesive composition described in claim 10 as a component.

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