JP5388524B2 - Copolyester resin and adhesive comprising the same - Google Patents

Description

  The present invention relates to a polyester resin for adhesive having ultraviolet absorptivity and an adhesive using the same.

Conventionally, polyester films have been widely used as insulating films in the electrical and electronic fields, but as resins for adhesives that adhere to them, polyester resins are mainly used from the viewpoint of adhesion to polyester films. Yes. A polyester film is suitable for protecting an electronic circuit because it has an appropriate UV-cutting property in addition to heat resistance, but the polyester-based adhesive used has also been required to have UV-cutting property. In order to increase the UV-cutting properties of polyester, films that increase UV absorption and reduce UV transmission by adding UV absorbers to the polyester film or incorporating a benzophenone structure into the polyester film itself have been proposed. (For example, patent document 1). However, the addition of an ultraviolet absorber is problematic because the transparency of the resin is lost and the adhesive strength is lowered. Moreover, transparency may be lost because an additive bleeds out by long-term use (for example, patent document 2). A polyester resin obtained by copolymerizing a polycyclic aromatic dicarboxylic acid is known as a polyester resin having an improved ultraviolet absorptivity without using an ultraviolet absorber (for example, Patent Document 3). However, such a copolyester resin is difficult to dissolve in a general-purpose solvent, and sufficient adhesiveness cannot be obtained even when used with an adhesive.
Japanese Patent Application Laid-Open No. 3-28185 JP-A-7-278523 Japanese Patent Laid-Open No. 11-80335

  An object of the present invention is to provide a copolyester resin having improved ultraviolet absorption while maintaining good adhesion to a polyester film, and an adhesive using the same.

  As a result of intensive studies to solve such problems, the present inventors have used a polycyclic aromatic dicarboxylic acid having 12 to 22 carbon atoms as a copolymerization component at a specific ratio, and are soluble in general-purpose solvents. The present inventors have found that the ultraviolet absorptivity of a copolymerized polyester resin having a viscosity can be improved, and have completed the present invention.

That is, the gist of the present invention is as follows.
(1) A copolymerized polyester resin composed of a polyvalent carboxylic acid component and a polyhydric alcohol component, wherein the polycyclic aromatic dicarboxylic acid having 12 to 22 carbon atoms is 1 to 1 with respect to the total polyvalent carboxylic acid. 40% by mole, 24 to 30% by mole of sebacic acid, a glass transition point of −10 to 50 ° C., and a plate-shaped molded product having a thickness of 2 mmt, the transmittance measured at a wavelength of 370 nm is less than 5%. Copolyester resin characterized by that.
(2) The copolyester resin according to (1), wherein the polycyclic aromatic dicarboxylic acid is 2,6-naphthalenedicarboxylic acid and / or 2,6-naphthalenedicarboxylic acid dimethyl ester.
(3) 15-45 mass% melt | dissolves the copolyester resin of (1) or (2) in the organic solvent obtained by mixing 1 type, or 2 or more types chosen from toluene, methyl ethyl ketone, ethyl acetate, and cyclohexanone. Adhesive.

  The copolymer polyester resin of the present invention uses a polycyclic aromatic dicarboxylic acid having 12 to 22 carbon atoms as a copolymer component at a specific ratio, and improves the ultraviolet absorptivity of the copolymer polyester resin having solubility in a general-purpose solvent. Therefore, it is possible to provide a copolymerized polyester resin having improved ultraviolet absorption while maintaining good adhesion to a polyester film, and an adhesive using the same.

  The copolymerized polyester resin of the present invention is composed of a polyvalent carboxylic acid component and a polyhydric alcohol component, and in addition to each one type of polyvalent carboxylic acid component and polyhydric alcohol component, one or more types of polyvalent carboxylic acid components. It is a polyester resin containing any of a monovalent carboxylic acid component, a polyhydric alcohol component, and an oxyacid component.

  The polyvalent carboxylic acid component blended in the copolymerized polyester resin of the present invention needs to contain 1 to 40 mol% of a polycyclic aromatic dicarboxylic acid having 12 to 22 carbon atoms with respect to the total polyvalent carboxylic acid. In order to balance the ultraviolet absorption of the obtained copolyester, solubility in general-purpose organic solvents, and adhesion, 1 mol% to 30 mol% is preferable, and 2 mol% to 24 mol% is most preferable. When the blending ratio of the polycyclic aromatic dicarboxylic acid having 12 to 22 carbon atoms is less than 1 mol%, sufficient ultraviolet light absorbability cannot be obtained for the copolyester resin, and the plate-shaped molded product having a thickness of 2 mmt has a wavelength of 370 nm. The transmittance measured at is not less than 5%. Further, when the blending of the polycyclic aromatic dicarboxylic acid having 12 to 22 carbon atoms exceeds 40 mol%, the ultraviolet light absorbability is obtained, but the obtained copolymer polyester resin is hardly dissolved in a general-purpose organic solvent, Moreover, the adhesiveness of the obtained adhesive agent falls. Moreover, since the polymerizability of the copolyester resin is also lowered, the yield is deteriorated and is not suitable for industrial implementation.

  Examples of the polycyclic aromatic dicarboxylic acid having 12 to 22 carbon atoms used in the present invention include divalent carboxylic acid components having a naphthalene skeleton, a phenanthrene skeleton, an anthracene skeleton, a pyrene skeleton, and a perylene skeleton. Moreover, the carboxylic acid ester which has each frame | skeleton may be sufficient. Among these, 2,6-naphthalenedicarboxylic acid and 2,6-naphthalenedicarboxylic acid dimethyl ester are particularly preferable because the copolymer polyester resin obtained can easily balance the ultraviolet absorptivity, solubility in general-purpose solvents, and adhesiveness.

The polyvalent carboxylic acid component to be blended in the copolymerized polyester resin of the present invention requires the use of a polycyclic aromatic dicarboxylic acid having 12 to 22 carbon atoms and sebacic acid. In addition to these polyvalent carboxylic acids , Aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids can be used. Specific examples of such dicarboxylic acid components include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and diphenic acid, and aliphatic dicarboxylic acids include oxalic acid, malonic acid, succinic acid, itaconic acid, fumaric acid, maleic acid, adipic acid, a Zerain acid, dodecanedioic acid, Aikosan diacid, dimer acid, hydrogenated dimer acid and the like, alicyclic dicarboxylic acids, 1,4-cyclohexanedicarboxylic An acid etc. are mentioned. Of these dicarboxylic acids, terephthalic acid, isophthalic acid and adipic acid are preferred.

  Examples of the dihydric alcohol component constituting the copolymer polyester resin of the present invention include aliphatic glycol, alicyclic glycol, and aromatic glycol. Specific examples of such dihydric alcohol components include aliphatic glycols such as polyethylene glycol, polytetramethylene glycol, polypropylene glycol, polyhexylene glycol, polynonanediol, poly (3-methyl-1,5). -Pentane) diol, neopentyl glycol, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1 , 6-hexanediol, 3-methyl-1,5-pentanediol, nonanediol and the like. Examples of the alicyclic glycol include 1,4-cyclohexanedimethanol, tricyclodecanedimethanol, spiroglyl. Examples of aromatic glycols include bisphenol-A polyethylene glycol adduct, bisphenol-A polypropylene glycol adduct, bisphenol-A polytetramethylene glycol adduct, and bisphenol-A ethylene oxide adduct. And propylene oxide adduct of bisphenol-A, ethylene oxide adduct of bisphenol-S, dimer diol and the like.

  In addition to the above dihydric alcohol component and dicarboxylic acid component, the copolyester resin of the present invention includes a trihydric or higher polyhydric alcohol component such as trimethylolpropane, glycerin, pentaerythritol, trimellitic acid, Trivalent or higher polyvalent carboxylic acid components such as merit acid, and further components such as ε-caprolactone, γ-butyrolactone, p-hydroxybenzoic acid and 3-hydroxyisophthalic acid may be contained. These may be contained in one or more types depending on the required performance of the resin without departing from the object of the present invention.

  The number average molecular weight of the copolyester resin of the present invention is preferably 15,000 to 100,000, more preferably 20,000 to 60,000. A number average molecular weight of less than 15,000 is not preferable because the adhesive strength tends to be insufficient. On the other hand, if the number average molecular weight exceeds 100,000, the solution becomes viscous when dissolved in a solvent and the workability is lowered when applied to a substrate, which is not preferable.

Glass transition temperature, - it is necessary that the 10 ° C. in the range of 50 ° C.. A glass transition point of less than −20 ° C. is not preferable because the resin tends to be difficult to handle and dispense during production. On the other hand, if the glass transition point exceeds 60 ° C., the adhesive strength tends to decrease, which is not preferable.

  The copolyester resin of the present invention is excellent in ultraviolet absorptivity, and its index is that the transmittance of light having a wavelength of 370 nm or less is less than 5%. If it is 5% or more, sufficient ultraviolet absorptivity cannot be obtained, and it becomes necessary to add an ultraviolet absorber or the like.

  Although it does not specifically limit as a manufacturing method for obtaining the copolyester resin composition of this invention of this invention, By the manufacturing method of well-known copolyester resin by melt polymerization methods, such as a direct esterification method and a transesterification method, Can be manufactured.

  In addition, as a raw material of the carboxylic acid component at the time of manufacturing the copolyester resin, carboxylic acid can be used as it is, but an ester derivative of carboxylic acid or a carboxylic acid anhydride may be used.

  Moreover, a well-known metal compound can be used as a catalyst at the time of manufacturing copolyester resin. Examples of such metal compounds include organic titanate compounds such as tetrabutyl titanate, alkali metals such as zinc acetate and magnesium acetate, acetates of alkaline earth metals, antimony trioxide, hydroxybutyltin oxide, and tin octylate. And so on. The amount of catalyst used in this case is 1. It is preferably used at 0% by mass or less. In addition, although said catalyst can also be used by 1 type, you may use it in mixture of 2 or more types.

  The copolymerized polyester resin of the present invention is used as a main component of an adhesive and has good adhesion to polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyarylate. Good adhesion to resins other than polyester resins, such as chlorinated resins such as polyvinyl chloride and polyvinylidene chloride, polycarbonate, polyethersulfone, polysulfone, polystyrene, acrylic resin, nylon resin, polyimide resin, etc. And also has good adhesion to metals such as copper, iron, aluminum and tinplate.

  As the adhesive of the present invention, the copolymer polyester resin of the present invention is dissolved in an organic solvent. The organic solvent used in the adhesive of the present invention is not particularly limited as long as it is an organic solvent that dissolves the copolyester resin for adhesive of the present invention. Specifically, benzene, Aromatic hydrocarbons such as toluene and xylene, methylene chloride, chloroform, carbon tetrachloride, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, chlorobenzene, dichlorobenzene and other chlorinated solvents, ethyl acetate, Ester solvents such as isophorone and γ-butyrolactone, ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, ether solvents such as diethyl ether, butyl cellosolve, ethyl cellosolve, tetrahydrofuran, 1,4-dioxane, Methanol, ethanol, propanol, iso Propanol, alcohol solvents butanol, butane, pentane, hexane, cyclohexane, heptane, octane, it includes aliphatic hydrocarbons nonane. In addition, as an organic solvent, only 1 type may be used or 2 or more types may be mixed and used. Toluene, methyl ethyl ketone, cyclohexanone and a mixed solvent thereof are particularly preferable.

  The solid concentration in the case of using an adhesive is preferably 15 to 45% by mass. When it becomes 15 mass% or less, the film thickness of the resin after application | coating becomes thin too much, and does not fully function as an adhesive agent. On the other hand, if it is 45% by mass or more, the solution becomes viscous and workability is lowered, and the resin tends not to be completely dissolved in the solvent.

  Further, the adhesive of the present invention may contain a resin other than the copolyester resin and a curing agent depending on the application. Examples of the resin other than the copolymer polyester resin include a urethane resin and an epoxy resin.

  Further, in the adhesive of the present invention, various additives such as repellency inhibitor, leveling agent, antifoaming agent, anti-waxing agent, rheology control agent, pigment dispersant, lubricant, flame retardant, etc., if necessary, Pigments such as titanium oxide, barium sulfate, and silica, and waxes such as olefin wax and carnauba wax may be blended.

  The adhesive of the present invention can be used for adhesion between various resins including the above-described polyester-based resins and adhesion between a resin material and a metal material. Without limiting the shape, for example, it can be used by being applied to materials having various shapes such as a film shape, a plate shape, a cylindrical shape, and a fiber shape.

  The adhesive of the present invention can be suitably used as an adhesive in the fields of electrical and electronic fields, machinery, automobiles, packaging materials such as foods and pharmaceuticals. Moreover, it can utilize also for the precoat metal coating material used with a metal can. Furthermore, it is suitable for glass bonding of a flat panel display, and has an effect of absorbing ultraviolet rays from the backlight of the flat panel display. In addition, the adhesive of the present invention is liquid and can be used in any form as described above, and is suitable as an adhesive in each of the above fields, and exhibits excellent performance derived from the above-described copolyester resin.

  EXAMPLES The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the following examples, and various modifications and applications are possible without departing from the spirit of the present invention. . In addition, about the characteristic of copolyester resin, it measured or evaluated by the following method.

1. Measuring method

(A) Constituent component The composition of the resin was analyzed using a proton NMR analyzer (manufactured by JEOL Ltd., JEOL LAMDBA300WB).

(B) Glass transition temperature Using a differential scanning calorimeter (Diamond DSC, manufactured by PerkinElmer Co., Ltd.), the temperature was raised to 200 ° C. at a temperature rising rate of 10 ° C./min, then rapidly cooled, and again a temperature rising rate of 10 ° C./min. The intermediate value of the two bending point temperatures derived from the glass transition in the temperature increase curve of the 2nd scan when the temperature was raised at γ was defined as the glass transition temperature.

(C) Ultraviolet absorption characteristics The copolymer polyester resin was dissolved in an organic solvent in which toluene and methyl ethyl ketone were mixed at a mass ratio of 8 to 2 at a solid concentration of 30% by mass, and then cast on a glass plate and dried, and the thickness was 2 mmt. A plate-like test piece was obtained. With this test piece, transmittance at a wavelength of 370 nm was measured using a spectrophotometer (manufactured by Shimadzu Corporation, UV-2450).

(D) Number average molecular weight It measured with the gel permeation chromatogram which used the high-speed liquid chromatograph (made by Shimadzu Corporation) using the ultraviolet-visible spectrophotometer altimeter SPD-6AV (detection wavelength: 254 nm) for a detector. Tetrahydrofuran was used as the solvent. The molecular weight in terms of polystyrene was determined and used as the molecular weight of the copolyester resin.

(E) Adhesive strength After the copolymer polyester resin was dissolved in a mixed solvent of toluene and methyl ethyl ketone (mass ratio of 8 to 2) to a concentration of 30% by mass, the solution was applied onto a 38 μm PET film, The solvent was removed to form a 20 μm thick adhesive layer. Next, the PET film on which the adhesive layer is formed is hot-pressed for 30 seconds under the conditions of 120 ° C. and 1 kgf / cm ² to obtain a laminate composed of the PET film / copolymerized polyester resin / the PET film. Obtained. Also, the PET film on which the adhesive layer obtained by the above method is formed is stacked on a metal plate and hot-pressed for 30 seconds under the conditions of 120 ° C. and 1 kgf / cm ² , thereby comprising a PET film / copolyester resin. A laminate comprising an adhesive layer / metal plate was obtained. Regarding the measurement of the peel strength of a laminate comprising a PET film / copolymerized polyester resin / a PET film, the obtained laminate was measured at a temperature of 20 ° C. and a humidity of 60 using a precision universal material tester 2020 manufactured by Intesco. T-peeling test was performed at a tensile rate of 50 mm / min in an atmosphere of%. Moreover, about the measurement of the peeling strength of the laminated body which consists of an adhesive bond layer / metal plate which consists of PET film / copolyester resin, the obtained laminated body is temperature 20 degreeC with the precision universal material testing machine 2020 type | mold made from Intesco. A 180 ° C. peel test was performed at a tensile rate of 50 mm / min in an atmosphere of 60% humidity. The peel strength is 5 N / cm.

(Creation of copolyester resin)

Example 1
In accordance with the charge composition shown in Table 1, as raw materials for the copolyester resin, terephthalic acid, isophthalic acid, sebacic acid, 2,6-naphthalenedicarboxylic acid, ethylene glycol, neopentyl glycol, and metal catalyst were charged into the autoclave, and the system The air inside was replaced with nitrogen. Subsequently, a copolyester resin P-1 was obtained by a normal transesterification method and a polycondensation method.

  About the obtained copolyester resin, the number average molecular weight, the glass transition point, the transmittance | permeability of 370 nm, and solvent solubility were evaluated. The results are shown in Table 2.

Examples 2-5
Copolyester resins P-2 to P-5 were obtained in the same manner as in Example 1 except that the charging composition shown in Table 1 was used. About the obtained copolyester resin, the number average molecular weight, the glass transition point, the transmittance | permeability of 370 nm, and solvent solubility were evaluated. The results are shown in Table 2.

Comparative Example 1
As raw materials for the copolyester resin, terephthalic acid, isophthalic acid, sebacic acid, ethylene glycol, neopentyl glycol, and a metal catalyst were charged into an autoclave to polymerize the copolyester resin. Here, 2,6-naphthalenedicarboxylic acid was not blended. The air in the system was replaced with nitrogen, and a copolyester resin P-6 was obtained by ordinary transesterification and polycondensation methods. About the obtained copolyester resin, the number average molecular weight, the glass transition point, the transmittance | permeability of 370 nm, and solvent solubility were evaluated. The results are shown in Table 2.

Comparative Example 2 to Comparative Example 4
Copolyester resins P-7 to P-9 were obtained in the same manner as in Example 1 except that the charging composition shown in Table 1 was used. About the obtained copolyester resin, the number average molecular weight, the glass transition point, the transmittance | permeability of 370 nm, and solvent solubility were evaluated. The results are shown in Table 2.

(Creation of copolymer polyester resin adhesive)

Examples 6-12
The copolyester resins P-1 to P-5 prepared in Examples 1 to 5 were dissolved in a mixed solvent of toluene and methyl ethyl ketone (mass ratio 8: 2) so that the solid concentration was 30% by mass. To obtain an adhesive. Using the obtained copolyester resin adhesive, the peel strength of PET / resin / PET and PET / resin / metal plate was measured to evaluate the adhesion. The results are shown in Table 3.

Comparative Example 5
The copolyester resin P-1 was dissolved in a mixed solvent of toluene and methyl ethyl ketone (mass ratio 8: 2) so that the solid concentration was 60% by mass, and an adhesive was obtained. It was not completely dissolved and an adhesive having a solid content concentration of 60% by mass could not be obtained.

Comparative Example 6
Copolymerized polyester resin P-1 was dissolved in a mixed solvent of toluene and methyl ethyl ketone (mass ratio 8: 2) so that the solid concentration was 50% by mass to obtain an adhesive. An attempt was made to apply an adhesive onto a PET film using the obtained copolymerized polyester resin adhesive, but the solution was viscous and an adhesive layer having a uniform film thickness could not be obtained.

Comparative Example 7
Copolymerized polyester resin P-1 was dissolved in a mixed solvent of toluene and methyl ethyl ketone (mass ratio 8: 2) so that the solid concentration would be 10% by mass to obtain an adhesive. Although it apply | coated to PET film using the obtained copolyester resin adhesive, since the viscosity of the solution was low, the resin layer with a film thickness of 20 micrometers was not able to be obtained.

Comparative Example 8
The copolyester resin P-7 prepared in Comparative Example 3 was dissolved in a mixed solvent of toluene and methyl ethyl ketone (mass ratio 8: 2) so that the solid content concentration was 30% by mass to obtain an adhesive. Using the obtained copolyester resin adhesive, the peel strength of PET / resin / PET and PET / resin / metal plate was measured to evaluate the adhesion. The adhesive strength of PET / resin / PET was 3 N / cm, and sufficient adhesive strength was not obtained.

  Examples 1 to 5 produced a copolymerized polyester resin according to the formulation of the present invention. Therefore, the number average molecular weight, glass transition point, transmittance of 370 nm, and solvent solubility of the obtained copolymerized polyester resin were: As shown in Examples 6 to 12, the adhesives obtained by dissolving these copolyester resins in a solvent had excellent adhesiveness. Therefore, when these copolyester resins are used as an adhesive, the adherend is bonded with practically sufficient adhesive strength and absorbs ultraviolet rays of 370 nm or less, so that the bonding of the members for the purpose of cutting ultraviolet rays is performed. Can be suitably used.

  In Comparative Example 1, since the copolymer polyester resin was prepared without blending 2,6-naphthalenedicarboxylic acid, the transmittance at 370 nm was large. In Comparative Example 2, since the blending amount of 2,6-naphthalenedicarboxylic acid was too large, it was not completely dissolved in the solvent. In Comparative Example 3 and Comparative Example 4, a predetermined amount of 2,6-naphthalenedicarboxylic acid was not blended, so that the transmittance at 370 nm was large.

In Comparative Example 5, since the solid content concentration was too high, the resin could not be completely dissolved in the solvent. Since the comparative example 6 became a viscous solution with a high solid content concentration, an adhesive layer having a uniform film thickness could not be obtained, and the adhesive strength could not be measured. In Comparative Example 7, since the solid content concentration was too low, the film thickness necessary for evaluating the adhesive strength could not be obtained. In Comparative Example 8, sufficient adhesive strength was not obtained.

Claims (3)

A copolymer polyester resin composed of a polyvalent carboxylic acid component and a polyhydric alcohol component, comprising 1 to 40 mol% of a polycyclic aromatic dicarboxylic acid having 12 to 22 carbon atoms with respect to the total polyvalent carboxylic acid. Further, it is characterized in that it contains 24 to 30 mol% of sebacic acid, has a glass transition point of −10 to 50 ° C., and has a transmittance of less than 5% measured at a wavelength of 370 nm in a 2 mm thick plate-like molded product. Copolyester resin.   The copolyester resin according to claim 1, wherein the polycyclic aromatic dicarboxylic acid is 2,6-naphthalenedicarboxylic acid and / or 2,6-naphthalenedicarboxylic acid dimethyl ester.   Adhesion obtained by dissolving 15 to 45% by mass of the copolyester resin according to claim 1 or 2 in an organic solvent obtained by mixing one or more selected from toluene, methyl ethyl ketone, ethyl acetate, and cyclohexanone. Agent.