Resin composition and hot melt adhesive composition

Abstract

To provide a resin composition which is excellent in water vapor barrier property while maintaining flowability and adhesion of a resin excellent in low pressure molding.SOLUTION: A resin composition contains a copolymer polyester resin (A), a polyolefin resin (B), a tackifier (C), an epoxy resin (D) and a filler (E), wherein the copolymer polyester resin (A) has a polycarboxylic acid component and a polyol component as structural units, and when the total polyol components are 100 mol%, the copolymer amount of a polyalkylene glycol component is 1 mol% or more and 25 mol% or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to resin compositions. More specifically, to resin compositions and hot-melt adhesive compositions that exhibit excellent fluidity, adhesion, and water vapor barrier properties. [Background technology]

[0002] While two-component epoxy resins and silicone resins have been commonly used as insulating resins for sealing electrical and electronic components in automobiles and electrical appliances, these methods require long processing times and can potentially damage electrical and electronic components due to shrinkage stress during curing. Therefore, in recent years, sealing electrical and electronic components using thermoplastic resins via low-pressure molding has become a known technique.

[0003] Polyester resin is a suitable material for sealing electrical and electronic components from the viewpoint of electrical insulation, water resistance, durability, and melt viscosity. However, in low-temperature, low-pressure molding, which is used to reduce damage to electrical and electronic components, the adhesion between the electrical and electronic components and the sealing resin is often insufficient, and the desired electrical insulation and water resistance are not fully achieved. For this reason, attempts to incorporate adhesion-enhancing agents having functional groups are being actively investigated from the viewpoint of improving adhesion (for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2004-210893 [Overview of the project] [Problems that the invention aims to solve]

[0005] In recent years, electrical and electronic components have sometimes been required to have high water vapor barrier properties in addition to the required physical properties mentioned above. However, when thermoplastic resins containing adhesion-enhancing agents, such as those described in Patent Document 1, are used, while adhesion is improved, there is a problem in that water vapor barrier properties cannot be guaranteed. Conventional technologies have not proposed a encapsulating resin composition that can achieve both water vapor barrier properties and resin fluidity, which is particularly excellent for low-pressure molding.

[0006] This invention was made against the backdrop of the problems of the prior art. In other words, the object of this invention is to provide a resin composition that has excellent water vapor barrier properties while maintaining the fluidity and adhesion of the resin, which are excellent for low-pressure molding. [Means for solving the problem]

[0007] As a result of diligent research, the inventors of the present invention have found that the above 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.

[0008] [1] Containing copolymer polyester resin (A), polyolefin resin (B), adhesion promoter (C), epoxy resin (D), and filler (E), A resin composition in which the copolymerized polyester resin (A) has a polycarboxylic acid component and a polyol component as constituent units, and when the total polyol component is 100 mol%, the copolymerized amount of the polyalkylene glycol component is 1 mol% or more and 25 mol% or less. [2] The resin composition according to [1], wherein the polyolefin resin (B) is an ethylene-α-olefin copolymer. [3] The resin composition according to [1] or [2], wherein the hydroxyl value of the adhesion-improving agent (C) is 1 to 500 KOH mg / g. [4] When the total amount of copolymerized polyester resin (A) and polyolefin resin (B) is 100 parts by mass, The polyolefin resin (B) content is 10 to 90 parts by mass. The content of the adhesion promoter (C) is 5 to 80 parts by mass. The content of the epoxy resin (D) is 1 to 10 parts by mass, The content of the filler (E) is 1 to 30 parts by mass, The resin composition according to any one of [1] to [3] above. [5] A hot-melt adhesive composition containing the resin composition according to any one of [1] to [4] above. [Advantages of the Invention]

[0009] The resin composition of the present invention exhibits excellent fluidity and adhesiveness, and further excellent water vapor barrier properties. Therefore, by using it as a sealing material for products that require high waterproofing, it is possible to manufacture products that satisfy the water vapor barrier properties. In particular, the resin composition of the present invention can be used as a hot-melt adhesive, and is particularly suitable for sealing applications of electrical and electronic components. [Brief Description of the Drawings]

[0010] [Figure 1] FIG. 1 shows a schematic diagram of a chart measured by a differential scanning calorimeter. [Modes for Carrying Out the Invention]

[0011] Hereinafter, the present invention will be described in detail.

[0012] [Copolyester resin (A)] The resin composition of the present invention contains a copolymerized polyester resin (A). The copolymerized polyester resin (A) used in the present invention has a polycarboxylic acid component and a polyol component as constituent units, and when the total polyol component is 100 mol%, the copolymerized amount of the polyalkylene glycol component is 1 mol% or more and 25 mol% or less. The polyalkylene glycol component is preferably 2 mol% or more, and preferably 5 mol% or more. It is also preferably 20 mol% or less, more preferably 15 mol% or less, and even more preferably 12 mol% or less. The polyalkylene glycol component is the so-called soft segment of the copolymerized polyester resin (A), and when the copolymerization ratio is above the lower limit, the melt viscosity of the resin composition of the present invention can be lowered, making it easier to mold at low pressure. Furthermore, by reducing the crystallization rate, problems such as the occurrence of short shots tend to be suppressed. When the copolymerization ratio of the polyalkylene glycol component is below the upper limit, the water vapor barrier properties are good.

[0013] The number-average molecular weight of the polyalkylene glycol component is not particularly limited, but is preferably 400 or more, and more preferably 800 or more. Having a number-average molecular weight of the polyalkylene glycol component above the lower limit imparts flexibility to the copolymerized polyester resin (A), reducing stress load after solidification when the resin composition is used as a hot-melt adhesive. For example, when applied as a sealant for electrical and electronic components, it can suppress stress-induced fracture and deterioration of the electrical and electronic components after sealing. Furthermore, from the viewpoint of compatibility with other components during the manufacturing of the copolymerized polyester resin (A), the number-average molecular weight of the polyalkylene glycol component is preferably 5000 or less, and more preferably 3000 or less.

[0014] Specific examples of polyalkylene glycol components include polyethylene glycol, polytrimethylene glycol, and polytetramethylene glycol. Among these, polytetramethylene glycol is the most preferred in terms of providing flexibility and reducing melt viscosity.

[0015] The polycarboxylic acid components constituting the copolymerized polyester resin (A) used in the present invention are not particularly limited, but the inclusion of aromatic dicarboxylic acids is preferable in that it can improve the heat resistance of the copolymerized polyester resin (A). Specific examples of aromatic dicarboxylic acids include terephthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, isophthalic acid, and 5-sodium sulfisophthalic acid. In particular, the aromatic dicarboxylic acid being terephthalic acid and / or naphthalenedicarboxylic acid is desirable in terms of improved heat resistance, high reactivity with glycol, polymerizability, and productivity. When the total polycarboxylic acid components constituting the copolymerized polyester resin (A) are set to 100 mol%, the sum of terephthalic acid and naphthalenedicarboxylic acid is preferably 50 mol% or more, more preferably 60 mol% or more, even more preferably 80 mol% or more, and particularly preferably 95 mol% or more, and the total polycarboxylic acid components may consist of terephthalic acid and / or naphthalenedicarboxylic acid.

[0016] Other polycarboxylic acid components constituting the copolymerized polyester resin (A) include alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid and tetrahydrophthalic anhydride, and aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, dimer acid, and hydrogenated dimer acid. These dicarboxylic acid components are used within a range that does not significantly lower the melting point of the copolymerized polyester resin (A), and their copolymerization ratio is 50 mol% or less of the total polycarboxylic acid components, preferably 40 mol% or less. In addition, it is also possible to use trifunctional or higher polycarboxylic acids such as trimellitic acid and pyromellitic acid as other polycarboxylic acid components constituting the copolymerized polyester resin (A). From the viewpoint of preventing gelation of the copolymerized polyester resin (A), the copolymerization ratio of trifunctional or higher polycarboxylic acids is preferably 10 mol% or less of the total polycarboxylic acid components, and more preferably 5 mol% or less.

[0017] The polyol components other than the polyalkylene glycol component that constitute the copolymerized polyester resin (A) are not particularly limited, but are preferably aliphatic glycols and / or alicyclic glycols, more preferably alkylene glycols having 2 to 10 carbon atoms, and even more preferably alkylene glycols having 2 to 8 carbon atoms. When the total polyol components constituting the copolymerized polyester resin (A) are 100 mol%, the aliphatic glycols and / or alicyclic glycols are preferably 50 mol% or more, and more preferably 70 mol% or more. Specific examples of preferred polyol components include ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, and 1,4-cyclohexanedimethanol. 1,4-butanediol and 1,4-cyclohexanedimethanol are most preferred because they can improve the heat resistance of the copolymerized polyester resin (A). Furthermore, trifunctional or higher polyols such as glycerin, trimethylolpropane, and pentaerythritol may be used as part of the polyol component. From the viewpoint of preventing gelation of the copolymerized polyester resin (A), it is preferable that the polyol component be 10 mol% or less of the total polyol component, and more preferably 5 mol% or less.

[0018] The polycarboxylic acid and polyol components constituting the copolymerized polyester resin (A) may include biomass-derived raw materials.

[0019] The glass transition temperature of the copolymer polyester resin (A) used in the present invention is preferably -20°C or lower, and more preferably -30°C or lower, from the viewpoint of thermal shock resistance.

[0020] The ester group concentration of the copolymer polyester resin (A) used in the present invention is 8000 equivalents / 10 6 It is desirable that the amount be less than or equal to g. Preferably, 7500 equivalents / 10 6 g or less, more preferably 7000 equivalents / 10 6 The amount is less than or equal to g. Furthermore, if oil resistance to cutting oil, kerosene, gasoline, engine oil, and other hydrocarbon solvents is required, the ester group concentration should be 1000 equivalents / 106 It is preferably g or more. More preferably 1500 equivalents / 10 6 g or more, still more preferably 2000 equivalents / 10 6 g or more. Here, the unit of the ester group concentration is the number of equivalents of the ester group per 10 6 g of the resin, and can be calculated from the composition of the copolymerized polyester resin and its copolymerization ratio.

[0021] The acid value of the copolymerized polyester resin (A) used in the present invention is preferably 100 equivalents / 10 6 g or less, more preferably 70 equivalents / 10 6 g or less, still more preferably 50 equivalents / 10 6 g or less. If the acid value is too high, the hydrolysis of the copolymerized polyester resin (A) may be promoted by the acid generated from the carboxylic acid, and a decrease in resin strength may be caused. The lower limit of the acid value is not particularly limited, but it is preferably 10 equivalents / 10 6 g or more, more preferably 20 equivalents / 10 6 g or more. If the acid value is too low, the adhesiveness may decrease.

[0022] The lower limit of the number average molecular weight of the copolymerized polyester resin (A) used in the present invention is not particularly limited, but it is preferably 3,000 or more, more preferably 5,000 or more, still more preferably 7,000 or more. Also, the upper limit of the number average molecular weight is not particularly limited, but it is preferably 80,000 or less, more preferably 70,000 or less, still more preferably 60,000 or less. If the number average molecular weight is too low, the hydrolysis resistance of the resin composition and the retention of strength and elongation under high temperature and high humidity may be insufficient. If the number average molecular weight is too high, the melt viscosity of the resin composition may become high, and the molding pressure may become too high or the molding may become difficult.

[0023] The upper limit of the melt viscosity of the copolymerized polyester resin (A) used in the present invention is preferably less than 3000 dPa·s, more preferably less than 2000 dPa·s, and even more preferably less than 1000 dPa·s at the molding temperature (e.g., 220°C). The lower limit of the melt viscosity is not particularly limited, but is preferably 50 dPa·s or more, more preferably 100 dPa·s or more, and even more preferably 200 dPa·s or more. If the melt viscosity is too high, the fluidity during molding will be poor, making molding difficult, and if the melt viscosity is too low, oil resistance and mechanical properties may be reduced, or molding defects such as burrs may not be eliminated.

[0024] The copolymerized polyester resin (A) used in the present invention is preferably a saturated polyester resin, 50 equivalents / 10 6 It may also be an unsaturated polyester resin having trace amounts of vinyl groups (less than g). If the unsaturated polyester has a high concentration of vinyl groups, crosslinking may occur during melting, which may result in poor melt stability.

[0025] The copolymerized polyester resin (A) of the present invention may be amorphous or crystalline, but crystalline is preferred. In the present invention, crystalline refers to a resin that shows a clear melting peak in either of the two heating steps when heated and melted to 230°C at a heating rate of 20°C / min using a differential scanning calorimeter (DSC), then cooled to -130°C at 20°C / min using liquid nitrogen, held for 5 minutes, and then heated from -130°C to 230°C at a heating rate of 20°C / min. On the other hand, amorphous refers to a resin that does not show a melting peak in either heating step.

[0026] When using the resin composition of the present invention as a hot-melt adhesive, rapid melting at 210-240°C is required to mold with minimal thermal degradation of the resin. For this reason, the upper limit of the melting point of the copolymerized polyester resin (A) is preferably 210°C, more preferably 200°C, and more preferably 190°C. Considering ease of handling at room temperature and normal heat resistance, the melting point of the copolymerized polyester resin (A) is preferably 90°C or higher, more preferably 100°C or higher, even more preferably 110°C or higher, particularly preferably 120°C or higher, and most preferably 130°C or higher.

[0027] A known method can be used to produce the copolymerized polyester resin (A) used in the present invention. For example, a copolymerized polyester resin can be obtained by esterifying the polycarboxylic acid component and the polyol component described later at 150 to 250°C, and then carrying out a polycondensation reaction at 230 to 300°C under reduced pressure. Alternatively, a copolymerized polyester resin can be obtained by transesterifying a derivative of a polycarboxylic acid, such as dimethyl ester, described later, and the polyol component at 150 to 250°C, and then carrying out a polycondensation reaction at 230 to 300°C under reduced pressure.

[0028] A method for determining the composition and composition ratio of copolymerized polyester resin (A) is, for example, to dissolve the copolymerized polyester resin (A) in a solvent such as deuterated chloroform and measure it using a nuclear magnetic resonance (NMR) spectrometer. 1 H-NMR and 13 Examples include 1C-NMR and quantitative analysis by gas chromatography after methanolysis of copolymer polyester resin (A) (hereinafter sometimes abbreviated as methanolysis-GC method). In the present invention, the copolymer polyester resin (A) can be dissolved and 1 If a solvent suitable for H-NMR measurement is available, 1 The composition and composition ratio will be determined by 1H-NMR. If a suitable solvent is not available, 1 If the composition ratio cannot be determined by H-NMR measurement alone, 13 We will employ or use in combination 13C-NMR or methanolysis-GC methods.

[0029] <Polyolefin resin (B)> The resin composition of the present invention contains a polyolefin resin (B). The inclusion of polyolefin resin (B) provides the resin composition with good water vapor barrier properties. The polyolefin resin (B) used in the present invention is not particularly limited, but polyethylene and ethylene copolymers are preferred from the viewpoint of adhesion to metals and films. Furthermore, a copolymerized polyolefin resin of two or more components is preferred from the viewpoint of dispersibility with the copolymerized polyester resin (A). Examples of copolymerized polyolefin resins of two or more components include ethylene-α-olefin copolymers such as ethylene-propylene copolymer, ethylene-butene copolymer, and ethylene-hexene copolymer; ethylene-unsaturated ester copolymers such as ethylene-vinyl acetate copolymer and ethylene-ethyl acrylate copolymer; ethylene-unsaturated carboxylic acid copolymers such as ethylene-vinyl acetate-maleic anhydride terpolymer and ethylene-ethyl acrylate-maleic anhydride terpolymer; and ethylene-unsaturated glycidyl compound copolymers such as ethylene-glycidyl methacrylate copolymer, ethylene-vinyl acetate-glycidyl methacrylate terpolymer, and ethylene-ethyl acrylate-glycidyl methacrylate terpolymer. Among these, ethylene-α-olefin copolymers are preferred. In the resin composition of the present invention, if polar groups are present in the polyolefin resin (B), the compatibility with the copolymerized polyester resin (B) changes, and the strain energy during crystallization of the copolymerized polyester resin (A) may not be relieved. Generally, polyolefin resins having polar groups tend to have higher compatibility with polyester resins than polyolefin resins without polar groups, but in the present invention, higher compatibility tends to lead to a greater decrease in adhesion over time. Therefore, it is preferable that the polyolefin resin (B) does not contain polar groups such as carboxyl groups or glycidyl groups.

[0030] The density of polyolefin resin (B) is 0.75 g / cm³. 3 The above is preferable, 0.80 g / cm³ 3 The above is more preferable, 0.95 g / cm³3 The following is preferable: 0.93 g / cm³ 3 The following is more preferable: 0.91 g / cm³ 3 The following is even more preferable: By using a low-density polyolefin resin within the aforementioned range, the polyolefin resin can be easily finely dispersed and mixed with copolymerized polyester resin, which is originally immiscible with polyolefin resin, and a homogeneous resin composition can be obtained using a general twin-screw extruder. Furthermore, by using a low-density, two-component or more copolymerized polyolefin resin as the polyolefin resin, it also appropriately acts to relieve the residual stress generated in the copolymerized polyester resin during injection molding over time, and the resin composition exhibits desirable properties such as long-term adhesive durability, reduction of stress generated due to environmental load, and improved water vapor barrier properties.

[0031] The polyolefin resin (B) used in the present invention preferably has a melt mass flow rate (hereinafter sometimes abbreviated as MFR) of 3 to 20 g / 10 min, as measured according to JIS K 7210-1:2014 (test temperature 190°C, nominal load 2.16 kg). If the MFR is less than 3 g / 10 min, the melt viscosity is too high, which may reduce compatibility with the copolymerized polyester resin (A) and impair adhesion. If the MFR exceeds 20 g / 10 min, the viscosity is low, the resin composition is extremely prone to softening, and the mechanical properties may be inferior.

[0032] When using the resin composition of the present invention as a hot-melt adhesive, rapid melting at 210-240°C is required to minimize thermal degradation of the resin during molding. Therefore, the upper limit of the melting point of the polyolefin resin (B) is preferably 210°C or lower, more preferably 190°C or lower. The lower limit is preferably 90°C or higher, more preferably 100°C or higher, even more preferably 110°C or higher, and particularly preferably 120°C or higher. It is preferable to make it 5-10°C or more higher than the heat resistance temperature required for the applicable application.

[0033] The content of polyolefin resin (B) in the resin composition of the present invention is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, even more preferably 20 parts by mass or more, and particularly preferably 25 parts by mass or more, when the total of copolymerized polyester resin (A) and polyolefin resin (B) is 100 parts by mass. It is also preferably 90 parts by mass or less, more preferably 70 parts by mass or less, preferably 60 parts by mass or less, and even more preferably 50 parts by mass or less. When the content ratio of polyolefin resin (B) is above the lower limit, good water vapor barrier properties are obtained. Furthermore, when the content ratio of polyolefin resin (B) is below the upper limit, good adhesion, moldability, and mechanical properties are obtained.

[0034] <Adhesive material (C)> The resin composition of the present invention contains an adhesion promoter (C). The inclusion of the adhesion promoter (C) provides good adhesion when the resin composition is used as a sealant, and also appropriately improves the fluidity of the resin composition. The adhesion promoter (C) used in the present invention is not particularly limited, and can include phenol compounds, xylene-modified phenol resins, terpene-modified phenol resins, and hydrogenated terpene-modified phenol resins obtained by hydrogenating terpene-modified phenol resins. In particular, from the viewpoint of compatibility with copolymerized polyester resin (A), xylene-modified phenol resins and terpene-modified phenol resins are preferred.

[0035] The adhesion promoter (C) used in the present invention preferably has hydroxyl groups. The presence of hydroxyl groups in the adhesion promoter (C) improves wettability to the substrate, thereby improving adhesion to the substrate and improving insulation. The hydroxyl value of the adhesion promoter (C) is preferably 1 KOH mg / g or more, more preferably 30 KOH mg / g or more, and even more preferably 50 KOH mg / g or more. Furthermore, it is preferably 500 KOH mg / g or less, more preferably 400 KOH mg / g or less, even more preferably 300 KOH mg / g or less, and particularly preferably 200 KOH mg / g or less.

[0036] The content of the adhesion promoter (C) in the resin composition of the present invention is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 20 parts by mass or more, per 100 parts by mass of the total of copolymerized polyester resin (A) and polyolefin resin (B). Furthermore, it is preferably 80 parts by mass or less, more preferably 50 parts by mass or less, and even more preferably 40 parts by mass or less. When the content of the adhesion promoter (C) is within the above range, particularly good adhesion can be achieved. In addition, a decrease in flexibility or embrittlement of the resin composition due to the reaction of the adhesion promoter (C) with other components is suppressed, and long-term stability is maintained.

[0037] <Epoxy resin (D)> The resin composition of the present invention contains epoxy resin (D). The inclusion of epoxy resin (D) provides excellent properties such as good initial adhesion and improved fluidity during molding due to reduced viscosity. Furthermore, epoxy resin (D) is thought to exert the effect of a compatibilizer between copolymer polyester resin (A) and polyolefin resin (B), as well as the effect of improving wettability to the substrate by introducing functional groups, thereby improving adhesion and insulation properties.

[0038] The epoxy resin (D) used in the present invention is not particularly limited as long as it is a compound having one or more epoxy groups in one molecule. Preferably, it is a resin having an average of 1.1 or more epoxy groups in one molecule. Examples include glycidyl ether types such as bisphenol A diglycidyl ether, bisphenol S diglycidyl ether, novolac glycidyl ether, and bromized bisphenol A diglycidyl ether; glycidyl ester types such as hexahydrophthalate glycidyl ester and dimer acid glycidyl ester; glycidylamine types such as triglycidyl isocyanurate, glycidylhindantoin, tetraglycidyldiaminodiphenylmethane, triglycidylparaaminophenol, triglycidylmetaaminophenol, diglycidylaniline, diglycidyltoluidine, tetraglycidylmetoxylendiamine, diglycidyltribromaniline, and tetraglycidylbisaminomethylcyclohexane; and alicyclic or aliphatic epoxyside types such as 3,4-epoxycyclohexylmethylcarboxylate, epoxidized polybutadiene, and epoxidized soybean oil. These can be used individually or in combination of two or more types.

[0039] The softening point of epoxy resin (D) is preferably 70°C or higher, and more preferably 80°C or higher, from the viewpoint of mechanical properties such as tensile strength and tensile elongation in a high-temperature environment (70°C or higher).

[0040] The number average molecular weight of the epoxy resin (D) is preferably 450 or more, more preferably 600 or more, and even more preferably 1000 or more. It is also preferably 40,000 or less, more preferably 30,000 or less, even more preferably 20,000 or less, particularly preferably 10,000 or less, and most preferably 5,000 or less. When the number average molecular weight is within the above range, the compatibility with the copolymerized polyester resin (A) and polyolefin resin (B) is appropriate, resulting in good mechanical properties and adhesion of the resin composition.

[0041] The epoxy resin (D) content in the resin composition of the present invention is preferably 1 part by mass or more, more preferably 3 parts by mass or more, per 100 parts by mass of the total of copolymerized polyester resin (A) and polyolefin resin (B). It is also preferably 10 parts by mass or less, and more preferably 5 parts by mass or less. When the epoxy resin (D) content is within the above range, it functions as a compatibilizer between copolymerized polyester resin (A) and polyolefin resin (B), and properties such as water vapor barrier properties and heat resistance are improved.

[0042] <Filler (E)> The resin composition of the present invention contains a filler (E). The inclusion of filler (E) provides the resin composition with good water vapor barrier properties. The filler (E) used in the present invention is not particularly limited, and can include glass beads, calcium carbonate, kaolin, talc, glass fibers, carbon fibers, clay, etc. The filler (E) used in the present invention is preferably in plate form, as this particularly improves water vapor barrier properties.

[0043] The content of filler (E) in the resin composition of the present invention is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, per 100 parts by mass of the total of copolymerized polyester resin (A) and polyolefin resin (B). When the content of filler (E) is above the lower limit, good water vapor barrier properties are obtained. In addition, the mechanical properties of the resin composition are improved, and the shear adhesive strength may be improved. Furthermore, the content of filler (E) is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less. When the content of filler (E) is below the upper limit, good adhesive properties are obtained.

[0044] <Resin composition> The resin composition of the present invention contains at least the copolymerized polyester resin (A), polyolefin resin (B), adhesion promoter (C), epoxy resin (D), and filler (E). Furthermore, it may optionally contain various additives such as antioxidants.

[0045] The resin composition of the present invention preferably has a melt viscosity of 5 to 1000 dPa·s at 220°C. The melt viscosity of the resin composition can be achieved by appropriately adjusting the types and blending ratios of the copolymerized polyester resin (A), polyolefin resin (B), adhesion promoter (C), epoxy resin (D), and filler (E). The melt viscosity at 220°C was measured as follows: The resin composition was dried to a moisture content of 0.1% or less, and then heated to 220°C using a flow tester (model CFT-500C) manufactured by Shimadzu Corporation. The stable resin composition was then subjected to a 98 N / cm² test using a 10 mm thick die with a pore diameter of 1.0 mm. 2 This is a measurement of viscosity when passed through at a pressure. While high melt viscosity of 1000 dPa·s or more provides high resin cohesiveness and durability, it requires high-pressure injection molding when sealing parts with complex shapes, which can cause part breakage. By using a resin composition with a melt viscosity of 1000 dPa·s or less, preferably 900 dPa·s or less, a product with excellent electrical insulation properties can be obtained at a relatively low injection pressure of 0.1 to 20 MPa without compromising its properties. Furthermore, from the viewpoint of resin composition injection operation, a lower melt viscosity at 220°C is preferable, but considering the adhesion and cohesiveness of the resin composition, a lower limit of 5 dPa·s or more is desirable, more preferably 10 dPa·s or more, more preferably 30 dPa·s or more, and most preferably 50 dPa·s or more.

[0046] The resin composition of the present invention may further contain an antioxidant. The antioxidant used in the present invention is not particularly limited as long as it can prevent oxidation of the copolymerized polyester resin (A), and can be a hindered phenol antioxidant, a phosphorus antioxidant, a thioether antioxidant, etc. For example, as a hindered phenol, 1,3,5-tris(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate, 1,1,3-tri(4-hydroxy-2-methyl-5-t-butylphenyl)butane, 1,1-bis(3-t-butyl-6-methyl-4-hydroxyphenyl)butane, 3,5-bis(1,1-dimethylethyl)-4-hydroxybenzenepropanoic acid, pentaerythrityltetrakis(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 3-(1,1-dimethylethyl)-4-hydroxy-5-methylbenzenepropanoic acid Neuic acid, 3,9-bis[1,1-dimethyl-2-[(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane, 1,3,5-trimethyl-2,4,6-tris(3',5'-di-t-butyl-4'-hydroxybenzyl)benzene, as phosphorus-based, 3,9-bis(p-nonylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, 3,9-bis(octadecyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5] Undecane, tri(mononylphenyl) phosphite, triphenoxyphosphine, isodecyl phosphite, isodecylphenyl phosphite, diphenyl 2-ethylhexyl phosphite, dinonylphenyl bis(nonylphenyl) ester phosphonic acid, 1,1,3-tris(2-methyl-4-ditridecylphosphite-5-t-butylphenyl)butane, tris(2,4-di-t-butylphenyl) phosphite, pentaerythritol bis(2,4-di-t-butylphenyl phosphite), 2,2'-methylene bis(4,6-di-t-butylphenyl Examples include 2-ethylhexyl phosphite, bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite, and thioethers such as 4,4'-thiobis[2-t-butyl-5-methylphenol]bis[3-(dodecylthio)propionate], thiobis[2-(1,1-dimethylethyl)-5-methyl-4,1-phenylene]bis[3-(tetradecylthio)-propionate], pentaerythritol tetrakis(3-n-dodecylthiopropionate), and bis(tridecyl)thiodipropionate. These can be used individually or in combination.

[0047] The antioxidant content is preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass or more, and even more preferably 0.3 parts by mass or more, per 100 parts by mass of the total of the copolymerized polyester resin (A) and the polyolefin resin (B). If the content is too low, it may adversely affect the long-term durability at high temperatures. It is also preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and even more preferably 1 part by mass or less. If the content is too high, it may adversely affect the adhesion, flame retardancy, etc.

[0048] The resin composition of the present invention may contain other resins that do not fall under any of the copolymerized polyester resin (A), polyolefin resin (B), adhesion promoter (C), epoxy resin (D), or filler (E), such as polyamide, polycarbonate, acrylic, ethylene vinyl acetate, isocyanate compounds, curing agents such as melamine, fillers such as mica, pigments such as carbon black and titanium dioxide, and flame retardants such as antimony trioxide and brominated polystyrene, as long as they do not impair the effects of the present invention. By incorporating these components, adhesion, flexibility, durability, etc., may be improved. In this case, the copolymerized polyester resin is preferably contained in an amount of 20 to 50% by mass of the total resin composition of the present invention, and more preferably 30 to 50% by mass. If the content of copolymerized polyester resin (A) is too low, the excellent adhesion, adhesive durability, and flexibility inherent in the copolymerized polyester resin itself tend to decrease, and if it is too high, the water vapor barrier properties tend to decrease.

[0049] Furthermore, if weather resistance is required for the resin composition of the present invention, it is preferable to add a light stabilizer. Examples of light stabilizers include benzotriazole-based light stabilizers, benzophenone-based light stabilizers, hindered amine-based light stabilizers, nickel-based light stabilizers, and benzoate-based light stabilizers. Examples of benzotriazole-based light stabilizers include 2-(3,5-di-tert-amyl-2'hydroxyphenyl)benzotriazole, 2-(2-hydroxy-5-tert-octylphenyl)benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2H-benzotriazole-2-yl)-p-cresol, 2-(2'-hydroxy-5'-methylphenyl)-benzotriazole, 2,4-di-tert-butyl-6-(5-chlorobenzotriazole-2-yl)phenol, and 2-[2-hydroxy-3,5-di(1,1-dimethylbenzyl)]-2H-benzotriazole. Examples of benzophenone-based light stabilizers include 2-hydroxy-4-(octyloxy)benzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, 2-hydroxy-4-n-dodecyloxybenzophenone, bis(5-benzoyl-4-hydroxy-2-methoxyphenyl)methane, 2-2'-dihydroxy-4-methoxybenzophenone, and 2,2'-dihydroxy-4,4'-dimethoxybenzophenone.Examples of hindered amine-based light stabilizers include bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, dimethyl succinate-1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, and poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidyl) Examples of nickel-based light stabilizers include [2,2'-thio-bis(4-tert-octylphenolate)]-2-ethylhexylamine-nickel-(II), nickel dibutyldithiocarbamate, and [2',2'-thio-bis(4-tert-octylphenolate)]n-butylamine-nickel. Examples of benzoate-based light stabilizers include 2,4-di-t-butylphenyl-3,5'-di-tert-butyl-4'-hydroxybenzoate. These light stabilizers can be used individually or in combination. When added, the amount is preferably 0.1% to 5% by mass of the total resin composition. If the amount is less than 0.1% by mass, the weather resistance effect may be poor. If it exceeds 5% by mass, it may adversely affect adhesion, etc.

[0050] <Hot melt adhesive composition> The resin composition of the present invention can be used as a hot-melt adhesive composition. As a hot-melt adhesive composition, it can be suitably used, for example, as a sealant for electrical and electronic components. Specific examples of usage include: By injecting the resin composition of the present invention into a mold in which the product to be waterproofed is set, a molded body in which the product is sealed can be obtained. More specifically, when using a screw-type hot-melt molding applicator, the resin composition is heated and melted at around 160 to 280°C, injected into the mold through an injection nozzle, and then, after a certain cooling time, the molded product can be removed from the mold to obtain the molded product.

[0051] The type of applicator used for hot melt molding is not particularly limited, but examples include the Nordson ST2, the IMC-18F9 vertical extrusion molding machine manufactured by Imoto Seisakusho, and the STX20 hybrid small vertical injection molding machine manufactured by Nissei Plastic Industrial Co., Ltd. [Examples]

[0052] Examples and comparative examples are given below to further illustrate the present invention, but the present invention is not limited in any way by these examples. The measurements described in the examples and comparative examples were taken by the following method.

[0053] <Composition of copolymerized polyester resin> The copolymerized polyester resin is dissolved in deuterated chloroform and subjected to nuclear magnetic resonance (NMR) spectroscopy. 1 The composition and compositional ratio were determined by 1H-NMR measurement.

[0054] <Measurement of melting point and glass transition temperature> Using a differential scanning calorimetry analyzer "DSC220" manufactured by Seiko Electronics Industries, Ltd., 5 mg of the sample was placed in an aluminum pan, sealed by pressing down on the lid, and heated to 230°C at a heating rate of 20°C / min until melted. Next, it was cooled to -130°C at 20°C / min using liquid nitrogen, held for 5 minutes, and then measured from -130°C to 230°C at a heating rate of 20°C / min. In the obtained curve, the intersection of the tangent line obtained from the baseline before the inflection point (1) and the tangent line obtained from the baseline after the inflection point (2) in the region where the inflection point appears in the DSC as shown in Figure 1 was defined as the glass transition temperature (Tg), and the minimum point of the endothermic peak (marked with an "x" in the figure) was defined as the melting point (Tm).

[0055] <Melting viscosity> Using a Shimadzu flow tester (CFT-500C model), a copolymer polyester resin or resin composition dried to a moisture content of 0.1% or less was filled into a cylinder in the center of a heating element set to 220°C. After 1 minute, a load was applied to the sample via a plunger, and the molten sample was extruded from a die (pore diameter: 1.0 mm, thickness: 10 mm) at the bottom of the cylinder at a pressure of 1 MPa. The descent distance and descent time of the plunger were recorded, and the melt viscosity was calculated. From the melt viscosity value, the melting characteristics (flowability) were evaluated according to the following evaluation criteria. Evaluation Criteria ◎: Melt viscosity at 220℃ less than 300 dPa·s ○: Melt viscosity at 220℃: 300 dPa·s or more and less than 500 dPa·s △: Melt viscosity at 220℃: 500 dPa·s or more and less than 1000 dPa·s ×: Melt viscosity at 220℃ 1000 dPa·s or higher

[0056] <Water vapor barrier properties> A resin film with a thickness of approximately 120 μm was produced by heat pressing using a heat press machine (SA-303, manufactured by Tester Industries Co., Ltd.). The heat press conditions were set to a temperature of 200°C, a press pressure of 10 MPa, and a press time of 30 seconds. Test pieces were cut out from the heat-pressed film using a cutting machine, in accordance with JIS Z0208:1976. The film was then set in a jig as specified in JIS Z0208:1976 and left to stand for a total of 96 hours in an environment of 25°C and 90% relative humidity (RH). Samples were taken and weighed 24, 48, 72, and 96 hours after the start of the test. The water vapor barrier properties (permeability) were calculated from the weight of water absorbed by calcium chloride between 24 and 48 hours, between 48 and 72 hours, and between 72 and 96 hours, and the average of the three water vapor barrier values ​​was used as the water vapor barrier property. The moisture permeability was calculated using the following formula. Moisture permeability (g / (m 2(24 hours) = (240 × m) / (t × s) m: Total increase in mass (mg) between the last two weighings in the test. t: Total time (h) between the last two weighings performed in the test. s: Moisture permeability area (cm²) 2 ) Evaluation Criteria ○: Moisture permeability 10 (g / m) 2 Less than 24 hours △: Moisture permeability 10(g / (m 2 ·24h)) or more 15(g / (m) 2 Less than 24 hours ×: Moisture permeability 15(g / (m 2 • 24 hours or more

[0057] <Adhesion Test (Shear Bond Strength)> Method for preparing shear bond strength test specimens The substrate (aluminum substrate: A1N30-H18 (thickness: 0.1 mm)) was cut to sizes of 70 mm x 25 mm and 40 mm x 25 mm, and the surface was wiped with acetone to remove oil. Next, the substrates were fixed inside a shear adhesion test mold so that the aluminum surface of the substrates was in contact with the molten resin composition, overlapping by 10 mm in length, resulting in a width of 25 mm and a resin composition thickness of 1 mm. Then, using a screw-type hot melt molding applicator (Imoto Seisakusho vertical low-pressure extrusion molding machine IMC-18F9), a resin composition with a moisture content of 0.1% or less was injected and molded. The molding conditions were: molding resin temperature 230°C, molding pressure 3.5 MPa, holding pressure 3.5 MPa, holding time 10 seconds, and discharge rotation set to 80% (maximum discharge being 100%). The molded product was removed from the mold, and a shear adhesion strength test specimen (substrate / resin composition layer / substrate) was obtained in which the molded resin composition was sandwiched between each substrate.

[0058] Shear bond strength test method The shear adhesive strength test specimens were stored for 24 hours in an atmosphere of 23°C and 50% relative humidity. Then, using an Autograph (AG-IS, manufactured by Shimadzu Corporation), each substrate was clamped in a chuck and the resin composition layer was peeled off in the shear direction, and the shear adhesive strength was measured. The tensile speed was 50 mm / min. Evaluation Criteria ○: Shear bond strength of 2.0 MPa or higher △: Shear bond strength of 1.0 MPa or more and less than 2.0 MPa ×: Shear bond strength less than 1.0 MPa

[0059] <Example of manufacturing copolymer polyester resin (A-1)> In a reaction vessel equipped with a stirrer, thermometer, and distillation condenser, 60 moles of 2,6-naphthalenedicarboxylic acid, 42.8 moles of 1,4-butanediol, 53.2 moles of 1,4-cyclohexanedimethanol, and 0.038 moles of tetrabutyl titanate were added, and the esterification reaction was carried out at 170-230°C for 2 hours. Subsequently, 0.2% by mass of the hindered phenol antioxidant AO330 relative to the amount of resin produced after polymerization, and 40 moles of dimer acid were added, and the esterification reaction was carried out at 200-230°C for 30 minutes. After that, 4 moles of PTMG1000 were added, and the esterification reaction was carried out at 200-230°C for another 30 minutes. After the esterification was complete, the temperature was raised to 255°C while the pressure in the system was slowly reduced, and the pressure was reduced to 665 Pa at 255°C over 60 minutes. The polycondensation reaction was then carried out at a pressure of 133 Pa or less for 30 minutes to obtain copolymerized polyester resin (A-1). The composition of copolymerized polyester resin (A-1) and the measured results of its melting point, glass transition temperature, and melt viscosity are shown in Table 1.

[0060] <Examples of manufacturing copolymer polyester resins (A-2) to (A-4)> Copolymerized polyester resins (A-2) to (A-4) were prepared in the same manner as copolymerized polyester resin (A-1), except that the types and ratios of polycarboxylic acid and polyol components were changed. The composition of the obtained copolymerized polyester resins and the measured results of melting point, glass transition temperature, and melt viscosity are shown in Table 1.

[0061] [Table 1]

[0062] The abbreviations used in Table 1 are as follows: TPA: Terephthalic acid, IPA: Isophthalic acid, NDC: 2,6-Naphthalenedicarboxylic acid, DA: Dimer acid, AA: Adipic acid, EG: Ethylene glycol, BD: 1,4-Butanediol, CHDM: 1,4-Cyclohexanedimethanol, PTMG1000: Polytetramethylene glycol (number average molecular weight 1000)

[0063] <Examples 1-8, Comparative Examples 1-7> Resin compositions (S-1) to (S-15) were obtained by melt-kneading copolymer polyester resin (A), polyolefin resin (B), adhesion promoter (C), epoxy resin (D), and filler (E) in the proportions shown in Table 2 using a twin-screw extruder at a die temperature of 160°C to 220°C. The melt viscosity, water vapor barrier properties, and shear adhesive strength of the resin compositions were evaluated by the method described separately. The evaluation results are shown in Table 2 below.

[0064] [Table 2]

[0065] The polyolefin resins, adhesion promoters, epoxy resins, and fillers used in Table 2 are as follows: Polyolefin resin (B-1): EUL731, manufactured by Sumitomo Chemical Co., Ltd., ethylene-1-butene copolymer, melting point: 113~117℃, density: 0.90 g / cm³ 3 Adhesion enhancer (C-1): YS Polystar G150, manufactured by Yasuhara Chemical Co., Ltd., terpene-modified phenol resin, hydroxyl value: 140 KOH mg / g Adhesion enhancer (C-2): YS Polystar T160, manufactured by Yasuhara Chemical Co., Ltd., terpene-modified phenol resin, hydroxyl value: 60 KOH mg / g Epoxy resin (D-1): jER(registered trademark) 1007K, manufactured by Mitsubishi Chemical Corporation, bisphenol A type solid epoxy resin, softening point: 128℃, number average molecular weight: 2,900 Filler (E-1): K-1, manufactured by Nippon Talc Co., Ltd., talc, plate-like, particle size (D50): 8.0 μm Filler (E-2): BYK-MAX CT 4255, manufactured by BYK-Chemie Japan Co., Ltd., montmorillonite, plate-like, particle size (D50): less than 40 μm

[0066] As is clear from Table 2, the resin compositions of Examples 1 to 8 all exhibited excellent properties in terms of water vapor barrier properties, shear adhesive strength, and melt viscosity. On the other hand, Comparative Example 1 had poor water vapor barrier properties because it contained a large amount of polyalkylene glycol in the copolymerized polyester resin. Comparative Example 2 had reduced flexibility and low shear adhesive strength because the copolymerized polyester resin did not contain polyalkylene glycol. Comparative Example 3 had poor water vapor barrier properties because it did not contain fillers. Comparative Example 4 had poor water vapor barrier properties because it did not contain polyolefin resin. Comparative Example 5 had poor shear adhesive strength and reduced water vapor barrier properties because it did not contain an adhesion promoter. Comparative Example 6 did not contain epoxy resin and had poor shear adhesive strength. Comparative Example 7 had poor water vapor barrier properties because it did not contain fillers. [Industrial applicability]

[0067] The resin composition of the present invention is useful as a hot-melt adhesive composition for waterproofing applications because it has a low melt viscosity during product molding, excellent adhesion to aluminum substrates, and excellent water vapor barrier properties.

Claims

1. It contains copolymerized polyester resin (A), polyolefin resin (B), adhesion promoter (C), epoxy resin (D), and filler (E), The copolymerized polyester resin (A) has a polycarboxylic acid component and a polyol component as constituent units, and when the total polyol component is 100 mol%, the copolymerized amount of the polyalkylene glycol component is 1 mol% or more and 25 mol% or less. The filler (E) is a plate-shaped filler. Resin composition.

2. The resin composition according to claim 1, wherein the polyolefin resin (B) is an ethylene-α-olefin copolymer.

3. The resin composition according to claim 1 or 2, wherein the hydroxyl value of the adhesion-imparting agent (C) is 1 to 500 KOH mg / g.

4. When the total amount of the copolymerized polyester resin (A) and the polyolefin resin (B) is 100 parts by mass, The content of the polyolefin resin (B) is 10 to 90 parts by mass, The content of the adhesive-forming agent (C) is 5 to 80 parts by mass, The epoxy resin (D) content is 1 to 10 parts by mass, The content of the filler (E) is 1 to 30 parts by mass. The resin composition according to any one of claims 1 to 3.

5. A hot melt adhesive composition containing the resin composition according to any one of claims 1 to 4.

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