Resin compositions and electrical / electronic component encapsulants

Abstract

[Problem] To provide a resin composition for electrical / electronic encapsulation which has excellent oil resistance and insulating properties, while retaining the intact flowability. [Solution] A resin composition comprising a polyester resin (A) having a solubility parameter (SP) value of 10.0 (cal / cm3)1 / 2 or greater, a polyamide (B), an epoxy resin (C), and an adhesion promoter (D).

Description

[Technical Field]

[0001] The present invention relates to a resin composition. More specifically, to a encapsulating resin composition and an electrical / electronic component encapsulant capable of encapsulating electrical / electronic components. [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 used as 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 promoters 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 [Disclosure of the Invention] [Problems that the invention aims to solve]

[0005] On the one hand, in addition to the above-mentioned required physical properties, oil resistance is sometimes required for electrical and electronic components. However, when using a thermoplastic resin blended with an adhesion-imparting agent as in Patent Document 1, although the adhesiveness is improved, there is a problem that oil resistance and insulation are not guaranteed. In the conventional technology, a sealing resin composition that can achieve both oil resistance and insulation while maintaining the fluidity of a resin excellent in low-pressure molding has not been proposed.

[0006] The present invention has been made in view of such problems of the conventional technology. That is, an object of the present invention is to provide a resin composition having excellent oil resistance, particularly not reducing physical properties during immersion in cutting oil, and excellent insulation while maintaining the fluidity of a resin excellent in low-pressure molding. In particular, the resin composition of the present invention is suitable for use in sealing electrical and electronic components.

Means for Solving the Problems

[0007] As a result of intensive studies, the present inventors have found that the above problems can be solved by the means shown below, and have reached the present invention. That is, the present invention has the following configuration.

[0008] [1] A resin composition containing a polyester resin (A), a polyamide (B), an epoxy resin (C), and an adhesion-imparting agent (D), the solubility parameter (SP) value of which is 10.0 (cal / cm 3 ) 1 / 2 or more.

[0009] [2] The resin composition according to [1] above, wherein the polyester resin (A) has terephthalic acid, isophthalic acid, butanediol, and polytetramethylene glycol as constituent units.

[0010] [3] The resin composition according to [1] or [2] above, wherein the glass transition temperatures of the polyester resin (A) and the polyamide (B) are both -20°C or lower.

[0011] [4] The resin composition according to any one of [1] to [3], wherein the polyamide (B) is a polyamide containing dimer acid as a constituent unit.

[0012] [5] The SP value of the adhesion promoter (D) is 9.0 (cal / cm²). 3 ) 1 / 2 The resin composition described in any of the above [1] to [4].

[0013] [6] The resin composition according to any one of [1] to [5] further comprising an antioxidant (E).

[0014] [7] A resin composition for sealing containing the resin compositions described in [1] to [6] above.

[0015] [8] An electrical and electronic component encapsulant sealed with the sealing resin composition described in [7] above. [Effects of the Invention]

[0016] The resin composition of the present invention exhibits excellent fluidity and superior oil resistance and insulation properties. Therefore, by using it as a encapsulant, particularly in electrical and electronic component encapsulants, it becomes possible to manufacture electrical and electronic component encapsulants that satisfy oil resistance and insulation requirements. [Brief explanation of the drawing]

[0017] [Figure 1] Figure 1 shows a schematic diagram of a chart measured by a differential scanning calorimetry analyzer. [Modes for carrying out the invention]

[0018] The present invention will be described in detail below.

[0019] <Polyester resin (A)> The polyester resin (A) used in the present invention preferably has a chemical structure in which a hard segment mainly composed of a polyester segment and a soft segment mainly composed of a polyalkylene glycol component are bonded by an ester bond. The polyester segment preferably mainly consists of a polyester having a structure that can be formed by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol and / or an alicyclic glycol.

[0020] The SP value of the polyester resin (A) used in the present invention is required to be 10.0 (cal / cm 3 ) 1 / 2 or more. Preferably, it is 10.5 (cal / cm 3 ) 1 / 2 or more. The SP value of cutting oil is generally about 7 - 8 (cal / cm 3 ) 1 / 2 . The lower the SP value and the closer it is to the SP value of the cutting oil, the better the affinity. When immersed in the cutting oil, the resin may absorb the cutting oil, and the oil resistance may deteriorate due to the swelling of the resin. On the other hand, if the SP value is too high, the compatibility with the polyamide (B) decreases, and instead, the insulation, oil resistance, and mechanical properties of the resin composition may be inferior. Therefore, the SP value is preferably 12.5 (cal / cm 3 ) 1 / 2 or less, more preferably 12.0 (cal / cm 3 ) 1 / 2 or less, and even more preferably 11.5 (cal / cm 3 ) 1 / 2 or less. The SP value can be adjusted by selecting monomers or adjusting the ester bond concentration. A high SP value can be obtained by copolymerizing a highly polar monomer or increasing the ester bond concentration. Here, the SP value used in the present invention is a value obtained by the Fedors' calculation method deduced from the molecular structure. The calculation method is described in the following reference: Polym.Eng.Sci., 14[2], 147 - 154(1974).

[0021] The glass transition temperature of the polyester resin (A) used in the present invention is preferably -20°C or lower, and more preferably -30°C or lower.

[0022] The upper limit of the ester group concentration of the polyester resin (A) used in the present invention is 8000 equivalents / 10 6 It is preferable that it be g. The preferred upper limit is 7500 equivalents / 10 6 g, comfortable 7000 equivalents / 10 6 The value is g. Furthermore, if oil resistance to cutting oil, kerosene, gasoline, engine oil, and other hydrocarbon solvents is required, the lower limit is 1000 equivalents / 10 6 It is preferable that it be g. A more preferable lower limit is 1500 equivalents / 10 6 g, more preferably 2000 equivalents / 10 6 It is g. Here, the unit of ester group concentration is resin 10 6 It is expressed as the number of ester groups per gram and can be calculated from the composition of the polyester resin and its copolymerization ratio.

[0023] The acid value of the polyester resin (A) used in this invention is 100 equivalents / 10 6 It is preferable that it is less than or equal to g, and more preferably 70 equivalents / 10 6 g or less, and more preferably 50 equivalents / 10 6 It is less than or equal to g. If the acid value is too high, the acid generated from the carboxylic acid may accelerate the hydrolysis of the polyester resin (A), which can lead to a decrease in resin strength. There is no particular lower limit to the acid value, but it is 10 equivalents / 10 6 It is preferable that it is 20 equivalents / 10 g or more. 6 The value should be 1g or more. If the acid value is too low, the adhesive properties may decrease.

[0024] The lower limit of the number-average molecular weight of the polyester resin (A) used in the present invention is not particularly limited, but is preferably 3,000 or more, more preferably 5,000 or more, and even more preferably 7,000 or more. The upper limit of the number-average molecular weight is also not particularly limited, but is preferably 80,000 or less, more preferably 70,000 or less, and even more preferably 60,000 or less. If the number-average molecular weight is too low, the hydrolysis resistance of the resin composition and the ability to maintain high elongation under high temperature and high humidity conditions may be insufficient, and if the number-average molecular weight is too high, the melt viscosity of the resin composition may become too high, resulting in excessively high molding pressure or difficulty in molding.

[0025] The upper limit of the melt viscosity of the polyester resin (A) used in the present invention is preferably less than 5000 dPa·s, more preferably less than 4000 dPa·s, and even more preferably less than 3000 dPa·s at the molding temperature (e.g., 230°C). The lower limit of the melt viscosity is not particularly limited, but is preferably 50 dPa·s or more, more preferably 300 dPa·s, even more preferably 500 dPa·s, and most preferably 1000 dPa·s. 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 decrease, or molding defects such as burrs may not be eliminated.

[0026] The 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.

[0027] The polyester resin (A) used in the present invention may be copolymerized with trifunctional or higher polycarboxylic acids or polyols such as trimellitic anhydride and trimethylolpropane as needed to form a branched polyester.

[0028] The polyester resin (A) used in the present invention requires rapid melting at 210-240°C in order to mold with minimal thermal degradation. For this reason, the upper limit of the melting point of the 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 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.

[0029] A known method can be used to produce the polyester resin (A) used in the present invention. For example, polyester can be obtained by esterifying the polycarboxylic acid component and 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, polyester can be obtained by transesterifying a derivative of polycarboxylic acid, such as dimethyl ester, described later, and a polyol component at 150 to 250°C, and then carrying out a polycondensation reaction at 230 to 300°C under reduced pressure.

[0030] <Hard segment of polyester resin (A)> The hard segments constituting the polyester resin (A) used in the present invention are preferably composed mainly of polyester segments. The polyester segments mainly consist of polycarboxylic acid components and polyol components as constituent units.

[0031] The polycarboxylic acid components constituting the polyester segment are not particularly limited, but the inclusion of aromatic dicarboxylic acids is preferable in that it can improve the heat resistance of the 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 polyester segment 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.

[0032] Other polycarboxylic acid components constituting the polyester segment 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 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 polyester segment. From the viewpoint of preventing gelation of the resin composition, 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.

[0033] Furthermore, while the polyol components constituting the polyester segment are not particularly limited, they are preferably aliphatic glycols and / or alicyclic glycols in that they can improve the heat resistance of the polyester resin (A). Among these, the aliphatic glycols and / or alicyclic glycols are preferably alkylene glycols having 2 to 10 carbon atoms, and more preferably alkylene glycols having 2 to 8 carbon atoms. Particularly preferred aliphatic glycol and alicyclic glycol components include ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, and 1,4-cyclohexanedimethanol, with 1,4-butanediol and 1,4-cyclohexanedimethanol being the most preferred. The aliphatic glycol and / or alicyclic glycol is preferably 50 mol% or more of the total polyol components, and more preferably 70 mol% or more. Furthermore, as part of the polyol component, trifunctional or higher polyols such as glycerin, trimethylolpropane, and pentaerythulitol may be used. From the viewpoint of preventing gelation of the resin composition, it is preferable that the polyol component be 10 mol% or less of the total polyol component, and more preferably 5 mol% or less.

[0034] As for the components constituting the polyester segment, those consisting of butylene terephthalate units or butylene naphthalate units are particularly preferred because they allow the polyester resin (A) to have a high melting point and improve heat resistance, and also in terms of moldability and cost performance.

[0035] The polycarboxylic acid and polyol components that make up the polyester segment may include biomass-derived raw materials.

[0036] <Polyester resin (A) soft segment> The soft segment of the polyester resin (A) used in the present invention preferably consists mainly of a polyalkylene glycol component. The copolymerization ratio of the soft segment is preferably 0.5 mol% or more, more preferably 2.5 mol% or more, and even more preferably 5 mol% or more, when the total polyol component constituting the polyester resin (A) is taken as 100 mol%. It is also preferably 50 mol% or less, more preferably 45 mol% or less, and even more preferably 40 mol% or less. If the copolymerization ratio of the soft segment is too low, the melt viscosity of the resin composition of the present invention tends to become high, making it impossible to mold at low pressure, or the crystallization rate is fast, leading to problems such as the occurrence of short shots. Conversely, if the copolymerization ratio of the soft segment is too high, it tends to result in problems such as insufficient heat resistance when used as a sealed body.

[0037] The number-average molecular weight of the soft segment is not particularly limited, but is preferably 400 or higher, and more preferably 800 or higher. If the number-average molecular weight of the soft segment is too low, flexibility cannot be imparted, which tends to lead to problems such as increased stress on the electronic substrate after encapsulation. Furthermore, the number-average molecular weight of the soft segment is preferably 5000 or less, and more preferably 3000 or less. If the number-average molecular weight is too high, it tends to lead to problems such as poor compatibility with other copolymerization components and inability to copolymerize.

[0038] Specific examples of polyalkylene glycol components used in soft segments include polyethylene glycol, polytrimethylene glycol, and polytetramethylene glycol. Polytetramethylene glycol is the most preferred in terms of providing flexibility and reducing melt viscosity.

[0039] The polyester resin (A) used in the present invention may be amorphous or crystalline, but crystalline is preferred. In the present invention, crystalline refers to a resin that, 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, shows a clear melting peak in either of these two heating steps. On the other hand, amorphous refers to a resin that does not show a melting peak in either heating step.

[0040] <Polyamide (B)> The resin composition of the present invention contains polyamide (B). The inclusion of polyamide (B) provides the resin composition with excellent oil resistance.

[0041] The glass transition temperature of the polyamide (B) used in the present invention is preferably -20°C or lower, and more preferably -30°C or lower.

[0042] The polyamide (B) used in this invention requires rapid melting at 210-240°C in order to mold it with minimal thermal degradation. For this reason, the softening point of polyamide (B) is preferably 210°C or lower, and more preferably 200°C or lower. Considering ease of handling at room temperature and normal heat resistance, the softening point of polyamide (B) 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.

[0043] In the resin composition of the present invention, when the total amount of polyester resin (A) and polyamide (B) is 100 parts by mass, the content of polyamide (B) is preferably 10 parts by mass or more and 50 parts by mass or less, and more preferably 20 parts by mass or more and 40 parts by mass or less. If the content of polyamide (B) is too low, the melt viscosity of the resin composition will increase, worsening the fluidity during molding, and if it is too high, the insulating properties may deteriorate under long-term test conditions such as immersion in cutting oil.

[0044] The polyamide (B) is preferably a polyamide containing dimer acid as a constituent unit. By copolymerizing dimer acid as the acid component of the polyamide, the melt viscosity can be lowered while maintaining the oil resistance of the polyamide. Therefore, in a resin composition with polyester resin (A), excellent oil resistance can be maintained while providing fluidity during molding. Furthermore, the glass transition temperature is also lowered, resulting in excellent low-temperature resistance.

[0045] <Epoxy resin (C)> The resin composition of the present invention contains an epoxy resin (C). The epoxy resin (C) 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 with a number average molecular weight in the range of 450 to 40,000 and 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.

[0046] The softening point of (C) in epoxy resin is preferably 70°C or higher, and more preferably 80°C or higher. If the softening point is low, the physical properties may deteriorate in high-temperature environments (70°C or higher).

[0047] The number-average molecular weight of the epoxy resin (C) is preferably 450 or higher, more preferably 600 or higher, and even more preferably 1000 or higher. If the number-average molecular weight is too low, the resin composition may soften easily, and its mechanical properties may deteriorate. Furthermore, it is preferably 40,000 or lower, more preferably 30,000 or lower, and even more preferably 20,000 or lower. If the number-average molecular weight is too high, the compatibility with the polyester resin (A) and polyamide (B) may decrease, and adhesion may be impaired.

[0048] In the present invention, by incorporating epoxy resin (C) into the resin composition, excellent properties such as good initial adhesion, adhesion durability against environmental loads such as immersion in cutting oil, and improved fluidity during molding due to reduced viscosity can be imparted when sealing electrical and electronic components. Epoxy resin (C) is thought to exert its effect as a compatibilizer between polyester resin (A) and polyamide (B), as well as improving wettability to the substrate by introducing functional groups, thereby improving insulation properties. The content of epoxy resin (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 polyester resin (A) and polyamide (B). If the amount of epoxy resin (C) is less than 5 parts by mass, it may not function as a compatibilizer between polyester resin (A) and polyamide (B). Furthermore, it is preferably 50 parts by mass or less, and more preferably 40 parts by mass or less. When epoxy resin (C) is added in parts 50 by mass or more, the productivity of the resin composition may be reduced, and furthermore, properties such as the heat resistance of the sealant may be reduced.

[0049] <Adhesion-enhancing agent (D)> The resin composition of the present invention contains an adhesion promoter (D). The adhesion promoter (D) used in the present invention is not particularly limited, and can be a phenol compound, a xylene-modified phenol resin, a terpene-modified phenol resin, or a hydrogenated terpene-modified phenol resin obtained by hydrogenating a terpene-modified phenol resin.

[0050] The SP value of the adhesion promoter (D) used in this invention is 9.0 (cal / cm²). 3 ) 1 / 2 The above is preferable. If the SP value is low, the oil resistance to kerosene, cutting oil, etc., and the mechanical properties may be inferior.

[0051] The adhesion promoter (D) used in the present invention preferably has hydroxyl groups. The presence of hydroxyl groups in the adhesion promoter (D) improves adhesion to the substrate and improves insulation. The hydroxyl value of the adhesion promoter (D) is preferably 1 to 500 KOH mg / g, more preferably 30 to 400 KOH mg / g, and even more preferably 50 to 300 KOH mg / g.

[0052] In the present invention, by incorporating the adhesion promoter (D) into the resin composition, good adhesion can be imparted and insulation properties can be significantly improved when sealing electrical and electronic components. The adhesion promoter (D) is thought to exert the effect of improving wettability to the substrate by introducing functional groups. The amount of adhesion promoter (D) in 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 polyester resin (A) and polyamide (B). It is also preferably 50 parts by mass or less, and even more preferably 40 parts by mass or less. If the blending ratio of adhesion promoter (D) is too low, good adhesion may not be achieved. On the other hand, if the blending ratio of adhesion promoter (D) is too high, the elastic modulus increases, which can reduce the flexibility of the resin and adversely affect adhesion, or the functional groups of the adhesion promoter (D) may react with the blended material, causing the resin to become brittle.

[0053] <Antioxidant (E)> The resin composition of the present invention may further contain an antioxidant (E). The antioxidant (E) used in the present invention is not particularly limited as long as it can prevent oxidation of the polyester resin (A), and can be a hindered phenol antioxidant, a phosphorus antioxidant, a thioether antioxidant, etc. For example, as hindered phenols, 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, pentaerythrityl Tetrakis(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 3-(1,1-dimethylethyl)-4-hydroxy-5-methylbenzenepropanoic 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 derivatives, 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 phospholucic 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)2-ethylhexyl phosphite, bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol Examples of diphosphites and thioethers include 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, which can be used individually or in combination.

[0054] The content of the antioxidant (E) 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 polyester resin (A) and polyamide (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.

[0055] <Resin composition> The resin composition of the present invention contains at least the polyester resin (A), polyamide (B), epoxy resin (C), and adhesion promoter (D), and optionally an antioxidant (E). Here, sealing refers to enclosing precision parts, etc., without gaps to prevent them from coming into contact with the outside air in order to protect them from dust and water. Because the resin composition of the present invention has excellent long-term reliability, it is particularly suitable for sealing electrical and electronic components among precision parts.

[0056] The resin composition of the present invention may contain other resins that do not fall under any of the polyester resin (A), polyamide (B), epoxy resin (C), or adhesion promoter (D) of the present invention, such as polyester, polyolefin, polycarbonate, acrylic, ethylene vinyl acetate, isocyanate compounds, curing agents such as melamine, fillers such as talc and 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 polyester resin (A) is preferably contained in an amount of 50% by mass or more, more preferably 55% by mass or more, and even more preferably 60% by mass or more, relative to the total resin composition of the present invention. If the content of polyester resin (A) is less than 50% by mass, the excellent adhesion to electrical and electronic components, adhesive durability, and flexibility that polyester resin (A) itself possesses tend to decrease.

[0057] 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.

[0058] A method for determining the composition and composition ratio of polyester resin (A) is, for example, to dissolve polyester resin (A) in a solvent such as deuterated chloroform and measure it. 1 H-NMR and 13 Examples include 1C-NMR and quantitative analysis by gas chromatography after methanolysis of polyester resin (A) (hereinafter sometimes abbreviated as methanolysis-GC method). In the present invention, the polyester resin (A) can be dissolved and 1 If a solvent suitable for H-NMR measurement is available, 1The 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.

[0059] The resin composition of the present invention preferably has a melt viscosity of 5 to 1000 dPa·s at 230°C, which can be achieved by appropriately adjusting the types and blending ratios of the polyester resin (A), polyamide (B), epoxy resin (C), adhesion promoter (D), and antioxidant (E). For example, increasing the copolymerization ratio of the polyetherdiol copolymerized with the polyester resin (A) or lowering the molecular weight of the polyester resin (A) tends to lower the melt viscosity of the resin composition of the present invention, while increasing the molecular weight of the polyester resin (A) tends to increase the melt viscosity of the resin composition of the present invention. Here, the melt viscosity at 230°C was measured as follows: The resin composition was dried to a moisture content of 0.1% or less, and then heated to 230°C using a flow tester (model CFT-500C) manufactured by Shimadzu Corporation. The stable resin composition was then tested at 98 N / cm² using a die with a thickness of 10 mm and 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, high-pressure injection molding is required when sealing parts with complex shapes, which can cause part breakage. By using a sealing resin composition having a melt viscosity of 1000 dPa·s or less, preferably 900 dPa·s or less, a sealing body (molded part) with excellent electrical insulation properties can be obtained at a relatively low injection pressure of 0.1 to 20 MPa, without impairing the properties of electrical and electronic components. Furthermore, from the viewpoint of the sealing resin composition injection operation, a lower melt viscosity at 230°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.

[0060] In this invention, the sealing performance of a specific component and a sealing resin composition is determined by preparing a test specimen by molding and bonding the sealing resin composition onto a metal wiring printed circuit board, and measuring its insulation resistance value. The method for preparing the test specimen and the method for measuring the insulation resistance value shall be carried out according to the methods described in the examples below.

[0061] The sealing resin composition of the present invention is molded by injecting it into a mold in which electrical and electronic components are set. More specifically, when using a screw-type hot melt molding applicator, the composition is heated and melted at approximately 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.

[0062] 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]

[0063] 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.

[0064] <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).

[0065] <SP value of polymer> The SP value of the polymer was calculated using Fedors' method by substituting the known cohesive energy density and molar volume of the atoms and atomic groups of the monomers constituting the polymer, as well as the atoms and atomic groups of the bonds formed during polymer polymerization, into the following formula. δ=(Σe i / Σv i ) 1 / 2 (cal / cm 3 ) 1 / 2 δ: SP value ((cal / cm) 3 ) 1 / 2 ) e i : Cohesive energy density of atoms and atomic groups (cal / mol) v i : Molar capacity of atoms and atomic groups (cm³) 3 / mol) e i and v i The values ​​used are those listed in Polym. Eng. Sci., 14[2], 147-154(1974).

[0066] <Melting properties (fluidity) test> Method for evaluating the melt viscosity of polyester resin (A) and resin composition Using a Shimadzu flow tester (CFT-500C model), a polyester resin (A) or resin composition with a moisture content of 0.1% or less was filled into a cylinder in the center of a heating element set to 230°C. After 1 minute of filling, 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. The melting properties of the resin composition were evaluated as follows based on its melt viscosity. Evaluation Criteria ◎: Melt viscosity at 230℃ less than 500 dPa·s ○: Melt viscosity at 230℃: 500 dPa·s or more and less than 800 dPa·s △: Melt viscosity @ 230℃ 800 dPa·s or more and less than 1000 dPa·s ×: Melt viscosity at 230℃ is 1000 dPa·s or higher

[0067] <Cutting fluid swelling characteristics (swelling rate after immersion in cutting fluid)> A 100mm x 100mm x 2mm thick flat sheet of resin composition was produced by injection molding using a vertical injection molding machine (TH40E, manufactured by Nissei Plastic Co., Ltd.). The injection molding conditions were: molding resin temperature 210°C, molding pressure 20 MPa, cooling time 30 seconds, and injection speed 10 mm / second. Three dumbbell-shaped test pieces of type 3, based on JIS K6251, were cut out from the molded plate using a test piece punching blade. Next, the test pieces were immersed in cutting oil (Hangsterfar S-500, manufactured by Nikko Casti Co., Ltd.) at room temperature (approximately 25°C) for 4 weeks. Immediately after removal, the total length of the test piece (approximately 100 mm) was measured with calipers, and the swelling rate of the cutting oil was calculated using the following formula. Cutting fluid swelling rate (%) = (Total length of test specimen after immersion (mm) - Total length of test specimen before immersion (mm)) ÷ Total length of test specimen before immersion (mm) × 100 The oil resistance of the resin composition was evaluated as follows based on the cutting fluid swelling rate. Evaluation Criteria ◎: Cutting fluid swelling rate less than 0.5% ○: Cutting fluid swelling rate 0.5% or more and less than 1.0% ×: Cutting fluid swelling rate 1.0% or higher

[0068] <Mechanical properties (Tensile elongation retention rate after immersion in cutting fluid)> A 100mm x 100mm x 2mm thick flat sheet of resin composition was produced by injection molding using a vertical injection molding machine (TH40E, manufactured by Nissei Plastic Co., Ltd.). The injection molding conditions were: molding resin temperature 210°C, molding pressure 20 MPa, cooling time 30 seconds, and injection speed 10 mm / second. Three dumbbell-shaped test specimens of type 3, based on JIS K6251, were cut out from the molded plate using a cutting machine. Next, the test specimens were immersed in cutting oil at room temperature (approximately 25°C) for 4 weeks. After immersion, the cutting oil was wiped off the surface, and the dumbbell-shaped test specimens of type 3 were clamped using an Autograph (AG-IS, manufactured by Shimadzu Corporation) with a chuck gap of 20 mm, and the mechanical properties were measured. The tensile speed was 500 mm / min. The tensile elongation retention rate was calculated using the following formula. Tensile elongation retention rate (%) = (Tensile elongation after 4 weeks of immersion in cutting oil / Tensile elongation at the start of molding) × 100 The mechanical properties of the resin composition were evaluated as follows, based on the tensile elongation retention rate. Evaluation Criteria ◎: Tensile elongation retention rate of 90% or more ○: Tensile elongation retention rate 70% or more to less than 90% △: Tensile elongation retention rate 50% or more to less than 70% ×: Tensile elongation retention rate less than 50%

[0069] <Insulation characteristics (insulation resistance value after immersion in cutting oil)> A resin composition was molded onto a substrate (substrate: glass epoxy) with a 40mm x 40mm x 1.6mm thick metal wiring pattern, to which a polyvinyl chloride (PVC) insulated wire with an outer diameter of approximately 1.45mm was soldered. This pattern was then applied using a small electric injection molding machine (LS-300i, manufactured by Canon Electronics Inc.). The molded product contained the metal wiring pattern and a portion of the PVC insulated wire. The molding conditions were: resin temperature 230°C, molding pressure 15MPa, cooling time 10 seconds, and injection speed 6mm / second. An insulation resistance meter SM-8220 (manufactured by HIOKI E.E. CORPORATION) was used to measure the insulation resistance of a sample immediately after molding under a 500V applied voltage, and of a sample after immersing a test piece in cutting oil at room temperature (approximately 25°C) for 4 weeks, followed by wiping off the cutting oil from the surface. The insulating properties of the resin composition were evaluated as follows based on its insulation resistance value. Evaluation Criteria ◎: Insulation resistance value of 100,000 MΩ or higher ○: Insulation resistance value 10,000 MΩ or more to less than 100,000 MΩ ×: Insulation resistance less than 10,000 MΩ In Table 2, E+N represents 10 to the power of N. For example, 2.86E+03 represents 2.86 × 10³ (= approximately 2860). In this measurement, 2.09E+00 is the minimum detection limit, and ≤2.09E+00 indicates that the value is below the detection limit.

[0070] <Example of polyester resin (A) manufacturing> In a reaction vessel equipped with a stirrer, thermometer, and distillation cooler, 1080 parts by mass of terephthalic acid, 582 parts by mass of isophthalic acid, 1893 parts by mass of 1,4-butanediol, and 1.9 parts by mass of tetrabutyl titanate were added, and the esterification reaction was carried out at 170-220°C for 2 hours. After the esterification reaction was completed, 1500 parts by mass of polytetramethylene glycol "PTMG1000" (manufactured by Mitsubishi Chemical Corporation) with a number average molecular weight of 1000 and 3 parts by mass of the hindered phenol antioxidant "Irganox 1330" (manufactured by Ciba-Geigy) were added, and the temperature was raised to 255°C while the pressure in the system was slowly reduced, reaching 665 Pa at 255°C over 60 minutes. Then, a polycondensation reaction was carried out at 133 Pa or less for 30 minutes to obtain polyester resin (A-1). The melt viscosity, melting point, glass transition temperature, and SP value of this polyester resin (A-1) are shown in Table 1. Furthermore, polyester resins (A-2) and (A-3) were synthesized using the same method as polyester resin (A-1). Their respective compositions and physical properties are shown in Table 1.

[0071] [Table 1]

[0072] The abbreviations used in Table 1 are as follows: TPA: Terephthalic acid, IPA: Isophthalic acid, AA: Adipic acid, NDC: 2,6-Naphthalenedicarboxylic acid, EG: Ethylene glycol, BD: 1,4-Butanediol, CHDM: Cyclohexanedimethanol, PTMG1000: Polytetramethylene ether glycol (number average molecular weight 1000), PTMG2000: Polytetramethylene ether glycol (number average molecular weight 2000)

[0073] A encapsulating resin composition was obtained by melt-kneading polyester resin (A), polyamide (B), epoxy resin (C), adhesion promoter (D), and antioxidant (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, cutting fluid swelling properties, mechanical properties, and insulating properties of the resin composition were evaluated using the method described separately. The evaluation results are shown in Table 2 below.

[0074] [Table 2-1]

[0075] [Table 2-2]

[0076] The polyamide (B), epoxy resin (C), adhesion promoter (D), and antioxidant (E) used in Table 2 are as follows: Polyamide (B-1): PA673, manufactured by Henkel, softening point: 185°C, Tg: -45°C, dimer acid copolymer polyamide Polyamide (B-2): PA6839, manufactured by Henkel, softening point: 195°C, Tg: -30°C, dimer acid copolymer polyamide Polyamide (B-3): Platamid M1276, manufactured by Arkema, softening point: 110°C, Tg: 30°C Epoxy resin (C-1): jER(registered trademark) 1007K, manufactured by Mitsubishi Chemical Corporation, softening point: 128℃ Epoxy resin (C-2): EPICLON® HP-7200HHH, manufactured by DIC Corporation, softening point: 105℃ Adhesion-enhancing agent (D-1): YS Polystar K125, manufactured by Yasuhara Chemical Co., Ltd., hydroxyl value: approx. 200 KOH mg / g, SP value: 9.3 (cal / cm²) 3 ) 1 / 2 , Tg: approx. 70℃ Adhesion-enhancing agent (D-2): YS Polystar T160, manufactured by Yasuhara Chemical Co., Ltd., hydroxyl value: approximately 60 KOH mg / g, SP value: 8.8 (cal / cm²) 3 ) 1 / 2 , Tg: approx. 100℃ Antioxidant (E-1): IRGANOX® 1010, manufactured by BASF Japan Ltd. Antioxidant (E-2): Rasmit LG, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.

[0077] As is clear from Table 2, the resin compositions of Examples 1 to 12 all showed excellent results in terms of melt viscosity, cutting fluid swelling properties, mechanical properties, and insulating properties. On the other hand, Comparative Example 1 had poor insulating properties because it did not contain an adhesion promoter. Comparative Examples 2 and 3 also had poor insulating properties because they did not contain epoxy resin. Comparative Example 4 had poor oil resistance due to the low SP value of the polyester resin used, as well as poor melt properties, mechanical properties, and insulating properties. [Industrial applicability]

[0078] The resin composition of the present invention is useful as a resin composition for encapsulating electrical and electronic components because it has a low melt viscosity when encapsulating electronic circuit boards, excellent adhesive strength to glass epoxy substrates and PBT substrates, and excellent oil resistance. Furthermore, the electrical and electronic component encapsulant of the present invention is particularly useful because it has excellent adhesiveness and cutting oil swelling resistance, thereby suppressing electrical leakage from electrical and electronic components. The electrical and electronic component encapsulant of the present invention is useful, for example, as a molded product of various connectors and harnesses for automotive, telecommunications, computer, and home appliance applications, or as a molded product of switches and sensors having electronic components and printed circuit boards.

Claims

1. The solubility parameter (SP) value is 10.0 (cal / cm³). ３ ) １／２ A resin composition comprising the above-mentioned polyester resin (A), polyamide (B), epoxy resin (C), and adhesion promoter (D), wherein when the total amount of the polyester resin (A) and the polyamide (B) is 100 parts by mass, the content of the polyamide (B) is 10 parts by mass or more and 50 parts by mass or less.

2. The resin composition according to claim 1, wherein the polyester resin (A) has terephthalic acid, isophthalic acid, butanediol, and polytetramethylene glycol as constituent units.

3. The resin composition according to claim 1 or 2, wherein the glass transition temperatures of both the polyester resin (A) and the polyamide (B) are -20°C or lower.

4. The resin composition according to any one of claims 1 to 3, wherein the polyamide (B) is a polyamide containing dimer acid as a constituent unit.

5. The SP value of the aforementioned adhesion promoter (D) is 9.0 (cal / cm²). ３ ) １／２ The resin composition according to any one of claims 1 to 4.

6. The resin composition according to any one of claims 1 to 5, further comprising an antioxidant (E).

7. A encapsulating resin composition containing the resin composition described in any one of claims 1 to 6.

8. An electrical and electronic component encapsulant sealed with the sealing resin composition described in claim 7.

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