WO2022158384A1

WO2022158384A1 - Resin composition and electrical/electronic part encapsulation body

Info

Publication number: WO2022158384A1
Application number: PCT/JP2022/001088
Authority: WO
Inventors: 雄基村上; 亮浜崎
Original assignee: 東洋紡株式会社
Priority date: 2021-01-20
Filing date: 2022-01-14
Publication date: 2022-07-28
Also published as: JPWO2022158384A1; TW202239867A

Abstract

[Problem] To provide a resin composition for an electrical/electronic encapsulation, the composition having excellent oil resistance and insulation performance without a reduction in fluidity. [Solution] Provided is a resin composition that contains a polyester resin (A) having a solubility parameter (SP) value of 10.0 (cal/cm³)^1/2 or greater, a dimer acid polyamide (B), and an epoxy resin (C).

Description

Resin composition and electrical/electronic component sealing body

The present invention relates to resin compositions. More particularly, it relates to a sealing resin composition and an electrical/electronic component sealing body capable of sealing electrical/electronic components.

Two-component curing epoxy resins and silicone resins have been commonly used as insulating resins for sealing electrical and electronic components used in automobiles and electrical appliances, but they require long processes. In recent years, sealing of electrical and electronic components by low-pressure molding using a thermoplastic resin has been known.

From the viewpoint of electrical insulation, water resistance, durability, and melt viscosity, polyester resin is used as a suitable material as a sealing resin for electrical and electronic parts. In low-pressure molding, the adhesion between the electrical/electronic component and the sealing resin is often insufficient, and the desired electrical insulation and waterproof properties are often not achieved. Therefore, from the viewpoint of raising the level of adhesiveness, an attempt to blend an adhesion imparting agent having a functional group has been actively studied (for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2004-210893

On the other hand, in addition to the required physical properties as described above, in electrical and electronic parts, oil resistance may be required. However, there was a problem that oil resistance and insulation were not ensured. In the prior art, no encapsulating resin composition has been proposed that can achieve both oil resistance and insulation while maintaining the fluidity of the resin, which is particularly excellent for low-pressure molding.

The present invention was made against the background of such problems of the prior art. That is, it is an object of the present invention to provide a resin composition having excellent insulating properties while maintaining resin fluidity excellent in low-pressure molding, without lowering oil resistance, particularly physical properties when immersed in cutting oil. It is in. In particular, the resin composition of the present invention is suitable for sealing electrical and electronic parts.

As a result of diligent studies, the present inventors have found that the above problems can be solved by the means shown below, and have arrived at the present invention. That is, the present invention consists of the following configurations.

[1] A resin composition comprising a polyester resin (A) having a solubility parameter (SP) value of 10.0 (cal/cm ³ ) ^1/2 or more, a dimer acid polyamide (B) and an epoxy resin (C).

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

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

[4] The resin composition according to any one of [1] to [3], further comprising an adhesion promoter (D).

[5] The resin composition according to [4] above, wherein the adhesion promoter (D) has an SP value of 9.0 (cal/cm ³ ) ^1/2 or more.

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

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

[8] A sealed electrical/electronic component sealed with the sealing resin composition according to [7] above.

The resin composition of the present invention exhibits excellent fluidity and is excellent in oil resistance and insulation. Therefore, by using it as a sealing material particularly in a sealed electrical/electronic component, it becomes possible to manufacture a sealed electrical/electronic component that satisfies oil resistance and insulation.

FIG. 1 shows a schematic diagram of a chart measured with a differential scanning calorimeter.

The present invention will be described in detail below.

<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 linked by an ester bond. Preferably, the polyester segment is mainly composed 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.

The SP value of the polyester resin (A) used in the present invention must be 10.0 (cal/cm ³ ) ^1/2 or more. It is preferably 10.5 (cal/cm ³ ) ^1/2 or more. The SP value of cutting oil is generally about 7 to 8 (cal/cm ³ ) ^1/2 . absorbs cutting oil, and swelling of the resin may deteriorate the oil resistance. On the other hand, if the SP value is too high, the compatibility with the dimer acid polyamide (B) may decrease, and the insulating properties, oil resistance, and mechanical properties of the resin composition may rather deteriorate. 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, still more preferably 11.5 (cal/cm 3 ) 1/2 or less. cm ³ ) ^1/2 or less. The SP value can be adjusted by selecting a monomer or adjusting the ester bond concentration, and a high SP value can be obtained by copolymerizing a highly polar monomer or by increasing the ester bond concentration. Here, the SP value used in the present invention is a value obtained by the Fedors calculation method estimated from the molecular structure. The calculation method is described in the following literature; Polym. Eng. Sci. , 14[2], 147-154 (1974).

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

The upper limit of the ester group concentration of the polyester resin (A) used in the present invention is desirably 8000 equivalents/10 ⁶ g. A preferred upper limit is 7500 equivalents/10 ⁶ g, more preferably 7000 equivalents/10 ⁶ g. Further, when oil resistance to cutting oil, kerosene, gasoline, engine oil, and other hydrocarbon solvents is required, the lower limit is preferably 1000 equivalents/10 ⁶ g. A more preferable lower limit is 1500 equivalents/10 ⁶ g, more preferably 2000 equivalents/10 ⁶ g. Here, the unit of the ester group concentration is represented by the equivalent number of ester groups per 10 ⁶ g of the resin, and can be calculated from the composition of the polyester resin and its copolymerization ratio.

The acid value of the 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. be. If the acid value is too high, the hydrolysis of the polyester resin (A) may be accelerated by the acid generated from the carboxylic acid, resulting in a decrease in resin strength. Although the lower limit of the acid value is not particularly limited, 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 adhesion may deteriorate.

Although the lower limit of the number average molecular weight of the polyester resin (A) used in the present invention is not particularly limited, it is preferably 3,000 or more, more preferably 5,000 or more, and still more preferably 7,000 or more. Although the upper limit of the number average molecular weight is not particularly limited, it is preferably 80,000 or less, more preferably 70,000 or less, and 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. The pressure may become too high and molding may become difficult.

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 a molding temperature (for example, 230°C). Although the lower limit of the melt viscosity is not particularly limited, it is preferably 50 dPa·s or more, more preferably 300 dPa·s, still more preferably 500 dPa·s, and most preferably 1000 dPa·s. If the melt viscosity is too high, the fluidity during molding may deteriorate, making it difficult to mold. may not be

The polyester resin (A) used in the present invention is preferably a saturated polyester resin, and may be an unsaturated polyester resin having a trace amount of vinyl groups of 50 equivalents/10 ⁶ g or less. If the unsaturated polyester has a high concentration of vinyl groups, cross-linking may occur during melting, resulting in poor melt stability.

The polyester resin (A) used in the present invention may be a branched polyester obtained by copolymerizing a tri- or higher-functional polycarboxylic acid or polyol such as trimellitic anhydride or trimethylolpropane, if necessary.

The polyester resin (A) used in the present invention is required to melt quickly at 210 to 240°C in order to mold while minimizing thermal deterioration. Therefore, the upper limit of the melting point of the polyester resin (A) is desirably 210°C. It is preferably 200°C, more preferably 190°C. Considering the handleability at normal temperature and the normal heat resistance, the melting point of the polyester resin (A) is preferably 90° C. or higher, more preferably 100° C. or higher, still more preferably 110° C. or higher, and particularly preferably 120° C. or higher. , most preferably 130° C. or higher.

A known method can be used as a method for producing the polyester resin (A) used in the present invention. For example, a polyester can be obtained by subjecting a polycarboxylic acid component and a polyol component, which will be described later, to an esterification reaction at 150 to 250° C., followed by a polycondensation reaction at 230 to 300° C. under reduced pressure. Alternatively, a derivative such as a dimethyl ester of a polycarboxylic acid described later and a polyol component are used for an ester exchange reaction at 150° C. to 250° C., followed by a polycondensation reaction at 230° C. to 300° C. under reduced pressure to form a polyester. Obtainable.

<Hard segment of polyester resin (A)>
It is preferable that the hard segment constituting the polyester resin (A) used in the present invention is mainly composed of a polyester segment. The polyester segment is composed mainly of a polycarboxylic acid component and a polyol component as structural units.

Although the polycarboxylic acid component that constitutes the polyester segment is not particularly limited, it is preferable that it contains an aromatic dicarboxylic acid because 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-sodiumsulisophthalic acid. In particular, the aromatic dicarboxylic acid is preferably terephthalic acid and/or naphthalenedicarboxylic acid in view of improved heat resistance and high reactivity with glycol, resulting in polymerizability and productivity. When the total polycarboxylic acid component constituting the polyester segment is 100 mol%, the total of terephthalic acid and naphthalene dicarboxylic acid is preferably 50 mol% or more, more preferably 60 mol% or more, and 80 mol. % or more, particularly preferably 95 mol % or more, and the total polycarboxylic acid component may be composed of terephthalic acid and/or naphthalenedicarboxylic acid.

Other polycarboxylic acid components constituting the polyester segment include alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid and tetrahydrophthalic anhydride, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, and dimers. Acids, dicarboxylic acids such as aliphatic dicarboxylic acids such as hydrogenated dimer acid. These dicarboxylic acid components are used within a range that does not greatly lower the melting point of the polyester resin (A), and the copolymerization ratio thereof is 50 mol % or less, preferably 40 mol % or less of the total polycarboxylic acid components. As other polycarboxylic acid components constituting the polyester segment, it is also possible to use tri- or higher functional polycarboxylic acids such as trimellitic acid and pyromellitic acid. From the viewpoint of preventing gelation of the resin composition, the copolymerization ratio of the tri- or higher functional polycarboxylic acid is preferably 10 mol % or less, more preferably 5 mol % or less, of the total polycarboxylic acid component.

Although the polyol component constituting the polyester segment is not particularly limited, it is preferably an aliphatic glycol and/or an alicyclic glycol in that it can improve the heat resistance of the polyester resin (A). Among them, the aliphatic glycol and/or the alicyclic glycol are preferably alkylene glycols having 2 to 10 carbon atoms, more preferably alkylene glycols having 2 to 8 carbon atoms. Particularly preferred aliphatic glycol and alicyclic glycol components are specifically ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol and the like. with 1,4-butanediol and 1,4-cyclohexanedimethanol being most preferred. Aliphatic glycol and/or alicyclic glycol preferably accounts for 50 mol% or more, more preferably 70 mol% or more, of the total polyol component. In addition, as a part of the polyol component, trifunctional or higher polyols such as glycerin, trimethylolpropane, pentaerythritol, etc. may be used, and from the viewpoint of preventing gelation of the resin composition, 10 mol % or less of the total polyol component. and more preferably 5 mol % or less.

As a component constituting the polyester segment, a butylene terephthalate unit or a butylene naphthalate unit is used because the polyester resin (A) has a high melting point and can improve heat resistance, and also from the viewpoint of moldability and cost performance. , is particularly preferred.

The polycarboxylic acid component and the polyol component that constitute the polyester segment may contain raw materials derived from biomass.

<Soft segment of polyester resin (A)>
It is preferable that the soft segment of the polyester resin (A) used in the present invention mainly consists 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, when the total polyol component constituting the polyester resin (A) is taken as 100 mol %. , is more preferably 5 mol % or more. Moreover, it is 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 be high, which tends to cause problems such as being unable to be molded at low pressure, or causing short shots due to high crystallization speed. On the other hand, if the copolymerization ratio of the soft segment is too high, problems such as insufficient heat resistance when used as a sealing body tend to occur.

Although the number average molecular weight of the soft segment is not particularly limited, it is preferably 400 or more, more preferably 800 or more. If the number average molecular weight of the soft segment is too low, flexibility cannot be imparted, and the stress load on the electronic substrate after sealing tends to increase. The soft segment preferably has a number average molecular weight of 5,000 or less, more preferably 3,000 or less. If the number-average molecular weight is too high, the compatibility with other copolymerization components tends to be poor, resulting in a problem of inability to copolymerize.

Specific examples of polyalkylene glycol components used in soft segments include polyethylene glycol, polytrimethylene glycol, and polytetramethylene glycol. Polytetramethylene glycol is most preferred in terms of imparting flexibility and lowering melt viscosity.

The polyester resin (A) used in the present invention may be amorphous or crystalline, but preferably crystalline. In the present invention, crystallinity means using a differential scanning calorimeter (DSC) to heat and melt at a temperature increase rate of 20 ° C./min to 230 ° C., then using liquid nitrogen at 20 ° C./min to -130 After cooling to ° C. and holding for 5 minutes, when heating from -130 ° C. to 230 ° C. at a heating rate of 20 ° C./min, it shows a clear melting peak in either of these two heating steps. point to something On the other hand, "amorphous" refers to those that do not show a melting peak in either heating step.

<Dimer Acid Polyamide (B)>
The resin composition of the present invention contains a dimer acid polyamide (B). Dimer acid polyamide (B) is a polyamide containing dimer acid as a structural unit. By copolymerizing a dimer acid as the acid component of the polyamide, the melt viscosity can be lowered while maintaining the oil resistance of the polyamide. Therefore, fluidity during molding can be imparted while maintaining excellent oil resistance in the resin composition with the polyester resin (A). In addition, the glass transition temperature is lowered and the low temperature resistance is also excellent.

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

The dimer acid polyamide (B) used in the present invention is required to melt rapidly at 210 to 240° C. in order to be molded with as little heat deterioration as possible. Therefore, the softening point of the dimer acid polyamide (B) is preferably 210°C or lower, more preferably 200°C or lower. Considering the handleability at room temperature and normal heat resistance, the softening point of the dimer acid polyamide (B) is preferably 90°C or higher, more preferably 100°C or higher, still more preferably 110°C or higher, and particularly preferably 120°C. °C or higher, most preferably 130 °C or higher.

In the resin composition of the present invention, when the total amount of the polyester resin (A) and the dimer acid polyamide (B) is 100 parts by mass, the content of the dimer acid polyamide (B) is 10 parts by mass or more and 50 parts by mass or less. is preferred, and 20 parts by mass or more and 40 parts by mass or less is more preferred. If the content of the dimer acid polyamide (B) is too low, the melt viscosity of the resin composition will increase and the fluidity during molding will deteriorate. It may get worse.

<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 having a number average molecular weight in the range of 450 to 40,000 and an average of 1.1 or more epoxy groups per molecule. glycidyl ether types such as bisphenol A diglycidyl ether, bisphenol S diglycidyl ether, novolac glycidyl ether, brominated bisphenol A diglycidyl ether; glycidyl ester types such as hexahydrophthalic acid glycidyl ester and dimer acid glycidyl ester; triglycidyl isocyanate Nurate, glycidylhindantoin, tetraglycidyldiaminodiphenylmethane, triglycidyl para-aminophenol, triglycidylmethaminophenol, diglycidylaniline, diglycidyltoluidine, tetraglycidylmetaxylenediamine, diglycidyltribromoaniline, tetraglycidylbisaminomethylcyclohexane, etc. glycidylamine type; alicyclic or aliphatic epoxide types such as 3,4-epoxycyclohexylmethyl carboxylate, epoxidized polybutadiene, and epoxidized soybean oil; These can be used alone or in combination of two or more.

The softening point of (C) of the epoxy resin is preferably 70°C or higher, more preferably 80°C or higher. If the softening point is low, physical properties may deteriorate in a high temperature (70° C. or higher) environment.

The number average molecular weight of the epoxy resin (C) is preferably 450 or more, more preferably 600 or more, and still more preferably 1000 or more. If the number average molecular weight is too small, the resin composition tends to soften, and mechanical properties may deteriorate. Also, it is preferably 40,000 or less, more preferably 30,000 or less, and still more preferably 20,000 or less. If the number average molecular weight is too large, the compatibility with the polyester resin (A) and the dimer acid polyamide (B) may be lowered, resulting in impaired adhesion.

In the present invention, by blending the epoxy resin (C) into the resin composition, when sealing electrical and electronic parts, good initial adhesion, adhesion durability against environmental loads such as immersion in cutting oil, and molding by low viscosity Excellent properties such as improved fluidity can be imparted. The epoxy resin (C) exerts an effect as a compatibilizer for the polyester resin (A) and the dimer acid polyamide (B), and also exhibits an effect of improving the wettability to the base material by introducing a functional group, and in turn improves the insulating properties. It is considered to be improved. The content of the epoxy resin (C) in the resin composition of the present invention is preferably 5 parts by mass or more, more preferably 100 parts by mass in total of the polyester resin (A) and the dimer acid polyamide (B). It is 10 parts by mass or more, more preferably 20 parts by mass or more. If the amount of the epoxy resin (C) is less than 5 parts by mass, it may not function as a compatibilizer for the polyester resin (A) and the dimer acid polyamide (B). Also, it is preferably 50 parts by mass or less, more preferably 40 parts by mass or less. When 50 parts by mass or more of the epoxy resin (C) is blended, the productivity of the resin composition may be inferior, and the properties such as heat resistance of the sealing body may be inferior.

<Adhesion imparting agent (D)>
The resin composition of the present invention may further contain a tackifier (D). The tackifier (D) used in the present invention is not particularly limited, and phenol compounds, xylene-modified phenolic resins, terpene-modified phenolic resins, hydrogenated terpene-modified phenolic resins obtained by hydrogenating terpene-modified phenolic resins, and the like can be used.

The SP value of the tackifier (D) used in the present invention is preferably 9.0 (cal/cm ³ ) ^1/2 or more. If the SP value is low, oil resistance to kerosene, cutting oil, etc. and mechanical properties may be inferior.

The tackifier (D) used in the present invention preferably has a hydroxyl group. Since the adhesion imparting agent (D) has a hydroxyl group, the adhesiveness to the base material can be improved, and the insulation can be improved. The hydroxyl value of the tackifier (D) is preferably from 1 to 500 KOHmg/g, more preferably from 30 to 400 KOHmg/g, even more preferably from 50 to 300 KOHmg/g.

In the present invention, by blending the adhesion imparting agent (D) into the resin composition, it is possible to impart good adhesion when sealing electrical and electronic components. The tackifier (D) is considered to exhibit the effect of improving the wettability to the substrate by introducing the functional group. The amount of the tackifier (D) in the present invention is preferably 5 parts by mass or more and 10 parts by mass or more with respect to a total of 100 parts by mass of the polyester resin (A) and the dimer acid polyamide (B). is more preferable, and 20 parts by mass or more is even more preferable. Also, it is preferably 50 parts by mass or less, more preferably 40 parts by mass or less. If the blending ratio of the tackifier (D) is too low, good adhesion may not be exhibited. On the other hand, if the blending ratio of the tackifier (D) is too high, the elastic modulus will increase and the flexibility of the resin will decrease, which will adversely affect the adhesiveness. It may react and embrittle the resin.

<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). agents can be used. For example, hindered phenols include 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-hydroxy- Benzenepropanoic acid, pentaerythrityl tetrakis(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 3-(1,1-dimethylethyl)-4-hydroxy-5-methyl-benzenepropanoic acid Ic acid, 3,9-bis[1,1-dimethyl-2-[(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]-2,4,8,10-tetra Oxaspiro[5.5]undecane, 1,3,5-trimethyl-2,4,6-tris(3′,5′-di-t-butyl-4′-hydroxybenzyl)benzene, as phosphorus system, 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(monononylphenyl)phosphite, triphenoxyphosphine, isodecylphosphite, isodecylphenylphosphite, diphenyl 2- Ethylhexylphosphite, dinonylphenylbis(nonylphenyl)ester phosphoric 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'-methylenebis(4,6-di-t-butylphenyl) 2-ethylhexyl Phosphite, bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite, 4,4'-thiobis[2-t-butyl-5-methylphenol]bis[3 as thioether -(dodecylthio)propionate], thiobis[2-(1,1-dimethylethyl)-5-methyl-4,1-phenylene]bis[3-(tetradecylthio)-propionate], pentaerythritol tetrakis(3-n -dodecylthiopropionate), bis(tridecyl)thiodipropionate), and these can be used alone or in combination.

The content of the antioxidant (E) is preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass with respect to a total of 100 parts by mass of the polyester resin (A) and the dimer acid polyamide (B). or more, more preferably 0.3 parts by mass or more. If the content is too low, it may adversely affect long-term durability at high temperatures. Also, it is 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 adhesion, flame retardancy, and the like.

<Resin composition>
The resin composition of the present invention contains at least the polyester resin (A), the dimer acid polyamide (B), and the epoxy resin (C), and if necessary, an adhesion promoter (D), an antioxidant (E ) is a composition containing Here, the term "sealing" refers to the wrapping of precision parts and the like without gaps so as to prevent dust and water from coming into contact with the outside air. INDUSTRIAL APPLICABILITY The resin composition of the present invention is excellent in long-term reliability, and is therefore suitable for use in sealing electrical and electronic parts, among precision parts.

The resin composition of the present invention includes polyesters, polyamides, polyolefins, and polycarbonates that do not correspond to any of the polyester resin (A), dimer acid polyamide (B), epoxy (C), and tackifier (D) of the present invention. , other resins such as acrylic and ethylene vinyl acetate, isocyanate compounds, curing agents such as melamine, fillers such as talc and mica, pigments such as carbon black and titanium oxide, flame retardants such as antimony trioxide and brominated polystyrene. There is no problem even if it is blended within a range that does not impair the effects of the present invention. Adhesiveness, flexibility, durability and the like may be improved by blending these components. 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 still more preferably 60% by mass or more, relative to the entire resin composition of the present invention. If the content of the polyester resin (A) is less than 50% by mass, the polyester resin (A) itself tends to have poor adhesion to electric and electronic parts, adhesion durability, and flexibility.

Furthermore, when the resin composition of the present invention requires weather resistance, 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. Benzotriazole 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-benzotriazol-2-yl)-p-cresol, 2-(2′-hydroxy- 5′-methylphenyl)-benzotriazole, 2,4-di-tert-butyl-6-(5-chlorobenzotriazol-2-yl)phenol, 2-[2-hydroxy-3,5-di(1, 1-dimethylbenzyl)]-2H-benzotriazole and the like. Benzophenone-based light stabilizers include 2-hydroxy-4-(octyloxy)benzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4 -methoxy-benzophenone-5-sulfonic acid, 2-hydroxy-4-n-dodecyloxybenzophenone, bis(5-benzoyl-4-hydroxy-2-methoxyphenyl)methane, 2-2'-dihydroxy-4- methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone and the like. Hindered amine 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, poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2 ,6,6-tetramethyl-4-piperidyl)imino}hexamethylene(2,2,6,6-tetramethyl-4-piperidyl)imino}], 1,3,5-tris(3,5-di- tert-butyl-4-hydroxybenzyl)-s-triazine-2,4,6(1H,3H,5H)trione, tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-s- triazine-2,4,6-(1H,3H,5H)trione and the like. Nickel-based light stabilizers include [2,2′-thio-bis(4-tert-octylphenolate)]-2-ethylhexylamine-nickel-(II), nickel dibutyldithiocarbamate, [2′,2′ -thio-bis(4-tert-octylphenolate)]n-butylamine-nickel and the like. Benzoate-based light stabilizers include 2,4-di-t-butylphenyl-3,5'-di-tert-butyl-4'-hydroxybenzoate and the like. These light stabilizers can be used alone or in combination. When added, the amount added is preferably 0.1% by mass or more and 5% by mass or less with respect to the entire resin composition. If it is less than 0.1% by mass, the weather resistance effect may be poor. If it exceeds 5% by mass, it may adversely affect the adhesion and the like.

As a method for determining the composition and composition ratio of the polyester resin (A), for example, the polyester resin (A) is dissolved in a solvent such as heavy chloroform and measured by ¹ H-NMR, ¹³ C-NMR, polyester resin (A) and quantification by gas chromatography measured after methanolysis (hereinafter sometimes abbreviated as methanolysis-GC method). In the present invention, if there is a solvent that can dissolve the polyester resin (A) and is suitable for ¹ H-NMR measurement, the composition and composition ratio are determined by ¹ H-NMR. If there is no suitable solvent or if the composition ratio cannot be specified by ¹ H-NMR measurement alone, ¹³ C-NMR or methanolysis-GC method is adopted or used in combination.

The resin composition of the present invention preferably has a melt viscosity of 5 to 1000 dPa s at 230 ° C., polyester resin (A), dimer acid polyamide (B), epoxy resin (C), tackifier (D) , can be achieved by appropriately adjusting the type and blending ratio of the antioxidant (E). For example, increasing the copolymerization ratio of the polyether diol to be copolymerized with the polyester resin (A) or decreasing the molecular weight of the polyester resin (A) tends to decrease the melt viscosity of the resin composition of the present invention. 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. is a value measured as follows. That is, the resin composition is dried to a moisture content of 0.1% or less, and then heated to 230 ° C. with a flow tester (model number CFT-500C) manufactured by Shimadzu Corporation. It is a measured value of viscosity when passed through a die having a thickness of 10 mm and a hole diameter at a pressure of 98 N/cm ² . A high melt viscosity of 1,000 dPa·s or more provides high resin cohesive strength and durability, but high-pressure injection molding is required when sealing parts with complex shapes, which may damage the parts. can occur. 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 having excellent electrical insulation can be obtained at a relatively low injection pressure of 0.1 to 20 MPa. (Molded parts) can be obtained, and the characteristics of electrical and electronic parts are not impaired. Also, from the viewpoint of the injection operation of the sealing resin composition, it is preferable that the melt viscosity at 230° C. is low. is 10 dPa·s or more, more preferably 30 dPa·s or more, and most preferably 50 dPa·s or more.

In the present invention, the sealing property of a specific member and the sealing resin composition is evaluated by preparing a measurement sample piece by bonding the sealing resin composition on a metal wiring printed circuit board by molding, and measuring the insulation resistance of this. Determined by measuring the value. The method for producing the test piece for measurement and the method for measuring the insulation resistance value shall be performed according to the method described in the examples described later.

The encapsulating resin composition of the present invention is molded by injecting it into a mold in which electrical and electronic components are set. More specifically, in the case of using a screw-type hot melt molding applicator, it is heated and melted at around 160 to 280 ° C., injected into a mold through an injection nozzle, and after a certain cooling time, it is molded. An object can be removed from the mold to obtain a molded product.

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

Examples and comparative examples are given below to describe the present invention in more detail, but the present invention is not limited by the examples. Each measured value described in Examples and Comparative Examples was measured by the following method.

<Measurement of melting point and glass transition temperature>
Using a differential scanning calorimeter "DSC220 type" manufactured by Seiko Electronics Industry Co., Ltd., 5 mg of the measurement sample was placed in an aluminum pan, the lid was pressed and sealed, and the temperature was increased to 230 ° C. at a rate of 20 ° C./min. , melted. Then, it was cooled to −130° C. at a rate of 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 (1) obtained from the baseline before the inflection point and the tangent line (2) obtained from the baseline after the inflection point in the portion where the inflection point appears in DSC as shown in FIG. was taken as the glass transition temperature (Tg), and the minimum point of the endothermic peak (x mark in the figure) was taken as the melting point (Tm).

<SP value of polymer>
The SP value of the polymer is determined by the Fedors method, and the known cohesive energy density and molar molecular volume of the atoms and atomic groups of the monomers constituting the polymer and the atoms and atomic groups of the bonds formed during polymer polymerization are substituted into the following formula. Calculated by

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 molecular volume of atoms and atomic groups (cm ³ /mol)

e _i and v _i are Polym. Eng. Sci. , 14[2], 147-154 (1974) were used.

<Melting characteristics (fluidity) test>
Method for evaluating the melt viscosity of the polyester resin (A) and the resin composition Using a flow tester (CFT-500C type) manufactured by Shimadzu Corporation, the moisture content was reduced to 0.1% or less in the cylinder at the center of the heating body set at 230 ° C. A dry polyester resin (A) or resin composition is filled. After 1 minute of filling, a load is applied to the sample through the plunger, and the melted sample is extruded from the die (hole diameter: 1.0 mm, thickness: 10 mm) at the bottom of the cylinder at a pressure of 1 MPa. The fall time was recorded and the melt viscosity was calculated.
Melting properties of the resin composition were evaluated as follows based on the melt viscosity.
Evaluation criteria ◎: Melt viscosity @ 230 ° C. less than 500 dPa s ○: Melt viscosity @ 230 ° C. 500 dPa s or more and less than 800 dPa s △: Melt viscosity @ 230 ° C. 800 dPa s or more and less than 1000 dPa s ×: Melt viscosity @ 230 ° C. 1000dPa・s or more

<Cutting oil swelling characteristics (swelling rate after immersion in cutting oil)>
A flat plate of the resin composition of 100 mm×100 mm×2 mmt was produced by injection molding using a vertical injection molding machine (TH40E manufactured by Nissei Plastics Co., Ltd.).
The injection molding conditions were a molding resin temperature of 210° C., a molding pressure of 20 MPa, a cooling time of 30 seconds, and an injection speed of 10 mm/second. Three dumbbell-shaped No. 3 test pieces based on JIS K6251 were cut out from the molded flat plate using a test piece punching blade. Next, the test piece is immersed in cutting oil (Hang Starfar S-500 manufactured by Nikko Casty Co., Ltd.) at room temperature (about 25 ° C.) for 4 weeks, and the total length of the test piece (about 100 mm) is measured with a vernier caliper immediately after taking it out. The oil swelling ratio was determined by the following formula.

Cutting oil swelling rate (%) = (total length of test piece after immersion (mm) - total length of test piece before immersion (mm)) / total length of test piece before immersion (mm) x 100

The oil resistance of the resin composition was evaluated as follows based on the cutting oil swelling rate.
Evaluation criteria ◎: Cutting oil swelling rate less than 0.5% ○: Cutting oil swelling rate 0.5% or more and less than 1.0% ×: Cutting oil swelling rate 1.0% or more

<Mechanical properties (tensile elongation retention rate after immersion in cutting oil)>
A flat plate of the resin composition of 100 mm×100 mm×2 mmt was produced by injection molding using a vertical injection molding machine (TH40E manufactured by Nissei Plastics Co., Ltd.).
The injection molding conditions were a molding resin temperature of 210° C., a molding pressure of 20 MPa, a cooling time of 30 seconds, and an injection speed of 10 mm/second. Three dumbbell-shaped No. 3 test pieces based on JIS K6251 were cut out from the molded flat plate using a cutout machine. Next, the test piece is immersed in cutting oil at room temperature (about 25 ° C.) for 4 weeks, and after immersion, the cutting oil on the surface is wiped off, and an autograph (AG-IS manufactured by Shimadzu Corporation) is used to measure between the chucks. A dumbbell-shaped No. 3 test piece was sandwiched so that the thickness was 20 mm, and the mechanical properties were measured. The pulling speed was 500 mm/min. The tensile elongation retention rate was calculated using the following formula.

Tensile elongation retention rate (%) = (tensile elongation after immersion in cutting oil for 4 weeks/tensile elongation at initial stage of molding) x 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 of 70% or more to less than 90% △: Tensile elongation retention rate of 50% or more to less than 70% ×: Tensile elongation retention rate of less than 50%

<Insulation properties (insulation resistance value after immersion in cutting oil)>
A small electric injection molding machine (Canon Electronics Co., Ltd. Using the company's LS-300i), the resin composition was molded to prepare a molding in which the metal wiring printed portion and a portion of the vinyl chloride insulated wire were sealed. The molding conditions were a molding resin temperature of 230° C., a molding pressure of 15 MPa, a cooling time of 10 seconds, and an injection speed of 6 mm/second. Using a super megohmmeter SM-8220 (manufactured by Hioki Electric Co., Ltd.), the test piece was immersed in a sample at the initial stage of molding and cutting oil at room temperature (about 25 ° C.) for 4 weeks at an applied voltage of 500 V. After immersion, the surface After wiping off the cutting oil, the insulation resistance value of the sample was measured.

The insulating properties of the resin composition were evaluated as follows based on the insulation resistance value.
Evaluation criteria ◎: Insulation resistance value of 100 MΩ or more ○: Insulation resistance value of 70 MΩ or more to less than 100 MΩ △: Insulation resistance value of 50 MΩ or more to less than 70 MΩ ×: Insulation resistance value of less than 50 MΩ
In Table 2, E+N represents 10 to the Nth power. For example, 2.86E+03 represents 2.86×10 to the power of 3 (=approximately 2860). In this measurement, 2.09E+00 is the minimum detection limit, and ≤2.09E+00 is below the detection limit.

<Production example of polyester resin (A)>
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 to a reactor equipped with a stirrer, a thermometer and a cooler for distillation. , 170 to 220° C. for 2 hours. After completion of the esterification reaction, 1500 parts by mass of polytetramethylene glycol "PTMG1000" (manufactured by Mitsubishi Chemical Corporation) having a number average molecular weight of 1000 and 3 parts by mass of a hindered phenolic antioxidant "Irganox 1330" (manufactured by Ciba-Geigy). The temperature was raised to 255° C., and the pressure in the system was slowly reduced to 665 Pa at 255° C. over 60 minutes. Further, a polycondensation reaction was carried out at 133 Pa or less for 30 minutes to obtain a polyester resin (A-1). Table 1 shows the melt viscosity, melting point, glass transition temperature and SP value of this polyester resin (A-1). Polyester resins (A-2) and (A-3) were synthesized in the same manner as polyester resin (A-1). Table 1 shows the composition and physical property values of each.

Abbreviations 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)

Polyester resin (A), dimer acid polyamide (B), epoxy resin (C), tackifier (D), and antioxidant (E) are mixed in the proportions shown in Table 2 using a twin-screw extruder. Resin compositions (S1) to (S18) were obtained by melt-kneading at a temperature of 160°C to 220°C. The melt viscosity, cutting oil swellability, mechanical properties, and insulating properties of the resin composition were evaluated by the methods described separately. The evaluation results are shown in Table 2 below.

The dimer acid polyamide (B), epoxy resin (C), tackifier (D) and antioxidant (E) used in Table 2 are as follows.
Dimer acid polyamide (B-1): PA673, manufactured by Henkel, softening point: 185°C, Tg: -45°C
Dimer acid polyamide (B-2): PA6839, manufactured by Henkel, softening point: 195°C, Tg: -30°C
Polyamide (B-3): Gramide T-802, manufactured by Toyobo Co., Ltd., melting point: 220°C, Tg: 50°C
Epoxy resin (C-1): jER (registered trademark) 1007K, manufactured by Mitsubishi Chemical Corporation, softening point: 128°C
Epoxy resin (C-2): EPICLON (registered trademark) HP-7200HHH, manufactured by DIC Corporation, softening point: 105°C
Tackifier (D-1): YS Polyster K125, manufactured by Yasuhara Chemical Co., Ltd., hydroxyl value: about 200 KOHmg/g, SP value: 9.3 (cal/cm ³ ) ^1/2 , Tg: about 70°C
Tackifier (D-2): YS Polyster T160, manufactured by Yasuhara Chemical Co., Ltd., hydroxyl value: about 60 KOHmg/g, SP value: 8.8 (cal/cm ³ ) ^1/2 , Tg: about 100°C
Antioxidant (E-1): IRGANOX (registered trademark) 1010, manufactured by BASF Japan Co., Ltd. Antioxidant (E-2): Rasmit LG, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.

As is clear from Table 2, the resin compositions of Examples 1 to 12 were all excellent in melt viscosity, cutting oil swelling, mechanical properties, and insulating properties. On the other hand, in Comparative Example 1, since it did not contain dimer acid polyamide, it was inferior in oil resistance, melting properties and insulation. Comparative Examples 2 to 4 did not contain an epoxy resin, and therefore were inferior in insulating properties. In Comparative Example 5, since the SP value of the polyester resin used was low, the oil resistance was lowered. The polyamide used in Comparative Example 6 did not have a dimer acid component, and was inferior in melting properties and insulating properties.

The resin composition of the present invention has a low melt viscosity when sealing electronic and electronic substrates, is extremely excellent in adhesive strength to glass epoxy substrates and PBT substrates, and has excellent oil resistance. It is useful as a resin composition. In addition, the electrical/electronic component sealing body of the present invention is particularly excellent in adhesiveness and cutting oil swelling property, so that electric leakage from the electrical/electronic component is suppressed, which is very useful. The electrical/electronic component sealed product of the present invention is useful as molded products such as connectors for automobiles, communications, computers, and household appliances, harnesses, electronic components, switches having printed circuit boards, and sensors.

Claims

A resin composition comprising a polyester resin (A) having a solubility parameter (SP) value of 10.0 (cal/cm 3 ) 1/2 or more, a dimer acid polyamide (B) and an epoxy resin (C).
The resin composition according to claim 1, wherein the polyester resin (A) has terephthalic acid, isophthalic acid, butanediol and polytetramethylene glycol as structural units.
The resin composition according to claim 1 or 2, wherein the polyester resin (A) and the dimer acid polyamide (B) both have a glass transition temperature of -20°C or lower.
The resin composition according to any one of claims 1 to 3, further comprising an adhesion promoter (D).
The resin composition according to claim 4, wherein the tackifier (D) has an SP value of 9.0 (cal/cm 3 ) 1/2 or more.
The resin composition according to any one of claims 1 to 5, further comprising an antioxidant (E).
A sealing resin composition containing the resin composition according to any one of claims 1 to 6.
A sealed electrical/electronic component sealed with the sealing resin composition according to claim 7.