JP-7855892-B2 - Resin composition and hot melt adhesive composition

Inventors

• 村上 雄基
• 岩下 祐司

Assignees

• 東洋紡エムシー株式会社

Dates

Publication Date

20260511

Application Date

20220328

Claims (5)

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

Description

This invention relates to resin compositions. More specifically, to resin compositions and hot-melt adhesive compositions exhibiting excellent fluidity, adhesion, and water vapor barrier properties. 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 lengthy processes 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. Polyester resin is a suitable material for sealing electrical and electronic components from the viewpoints of electrical insulation, water resistance, durability, and melt viscosity. However, in low-temperature, low-pressure molding aimed at reducing damage to electrical and electronic components, the adhesion between the electrical and electronic components and the sealing resin is often insufficient, resulting in inadequate electrical insulation and water resistance. Therefore, attempts to incorporate adhesion-enhancing agents with functional groups are being actively investigated to improve adhesion (for example, Patent Document 1). Japanese Patent Publication No. 2004-210893 Figure 1 shows a schematic diagram of a chart measured by a differential scanning calorimetry analyzer. The present invention will be described in detail below. <Copolymerized polyester resin (A)> The resin composition of the present invention contains a copolymerized polyester resin (A). The copolymerized polyester resin (A) used in the present invention has a polycarboxylic acid component and a polyol component as constituent units, and when the total polyol component is 100 mol%, the copolymerized amount of the polyalkylene glycol component is 1 mol% or more and 25 mol% or less. The polyalkylene glycol component is preferably 2 mol% or more, and preferably 5 mol% or more. It is also preferably 20 mol% or less, more preferably 15 mol% or less, and even more preferably 12 mol% or less. The polyalkylene glycol component is the so-called soft segment of the copolymerized polyester resin (A), and when the copolymerization ratio is above the lower limit, the melt viscosity of the resin composition of the present invention can be lowered, making it easier to mold at low pressure. Furthermore, by reducing the crystallization rate, problems such as the occurrence of short shots tend to be suppressed. When the copolymerization ratio of the polyalkylene glycol component is below the upper limit, the water vapor barrier properties are good. The number-average molecular weight of the polyalkylene glycol component is not particularly limited, but it is preferably 400 or more, and more preferably 800 or more. Having a number-average molecular weight of the polyalkylene glycol component above the lower limit imparts flexibility to the copolymerized polyester resin (A), reducing stress load after solidification when the resin composition is used as a hot-melt adhesive. For example, when applied as a sealant for electrical and electronic components, it can suppress stress-induced fracture and deterioration of the electrical and electronic components after sealing. Furthermore, from the viewpoint of compatibility with other components during the manufacturing of the copolymerized polyester resin (A), the number-average molecular weight of the polyalkylene glycol component is preferably 5000 or less, and more preferably 3000 or less. Specific examples of polyalkylene glycol components include polyethylene glycol, polytrimethylene glycol, and polytetramethylene glycol. Among these, polytetramethylene glycol is the most preferred in terms of imparting flexibility and achieving low melt viscosity. The polycarboxylic acid components constituting the copolymerized polyester resin (A) used in the present invention are not particularly limited, but the inclusion of aromatic dicarboxylic acids is preferable in that it can improve the heat resistance of the copolymerized polyester resin (A). Specific examples of aromatic dicarboxylic acids include terephthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, isophthalic acid, and 5-sodium sulfisophthalic acid. In particular, the aromatic dicarboxylic acid being terephthalic acid and/or naphthalenedicarboxylic acid is desirable in terms of improved heat resistance, high reactivity with glycol, polymerizability, and productivity. When the total polycarboxylic acid components constituting the copolymerized polyester resin (A) are set to 100 mol%, the sum of terephthalic acid and naphthalenedicarboxylic acid is preferably 50 mol% or more, more preferably 60 mol% or more, even more preferably 80 mol% or more, and particularly preferably 95 mol% or more. It is also acceptable for the total polycarboxylic acid components to con