Resin composition and hot-melt adhesive composition

Abstract

The present invention provides a sealing resin composition having excellent water vapor barrier properties without impairing various characteristics required for a resin composition. The resin composition according to the present disclosure contains a polyolefin resin (A), an acid-modified polyolefin resin (B), a styrene-isobutylene-styrene block copolymer (C), an adhesiveness imparting agent (D), and a filler (E). The polyolefin resin (A) contains (A-1) a polypropylene resin, (A-2) a propylene-α-olefin copolymer having a tensile elongation of 1,000% or more, and (A-3) a propylene-α-olefin copolymer having a tensile elongation of at least 300% but less than 1,000%. The amounts of (A-1), (A-2), and (A-3) are within prescribed ranges.

Description

Resin composition and hot melt adhesive composition

[0001] This invention relates to resin compositions and hot-melt adhesive compositions.

[0002] Traditionally, insulating resins such as two-component epoxy resins and silicone resins have been widely used to seal electrical and electronic components installed in automobiles and electrical appliances. However, these resins have drawbacks, such as requiring long curing times and potentially damaging electrical and electronic components due to shrinkage stress during curing. Therefore, in recent years, sealing technology using thermoplastic resins with low-pressure molding, which offers superior productivity and reduces stress on components, has attracted attention.

[0003] Among thermoplastic resins, polyester resins are being considered as encapsulating materials because they offer an excellent balance of electrical insulation, water resistance, durability, and fluidity during melting. However, low-temperature, low-pressure molding, which is necessary to avoid damage to electrical and electronic components, results in insufficient adhesion to these components, making it difficult to ensure the required electrical insulation and waterproofing properties. To address this, techniques have been proposed to incorporate adhesion promoters with functional groups to improve adhesion (for example, Patent Document 1).

[0004] Japanese Patent Publication No. 2004-210893

[0005] In recent years, electrical and electronic components have been required to have not only conventional physical properties but also high water vapor barrier properties (i.e., low water vapor permeability). However, conventional techniques that incorporate adhesion promoters, such as those described in Patent Document 1, improve adhesion but lack sufficient water vapor barrier properties. Thus, a encapsulating resin composition that achieves both high water vapor barrier properties and fluidity, adhesion, heat-resistant adhesion, and thermal shock resistance suitable for low-pressure molding has not been proposed until now.

[0006] This invention has been made in view of the problems of the prior art, and aims to provide a sealing resin composition that is excellent in water vapor barrier properties without impairing the various properties required of a resin composition (fluidity, adhesion, heat-resistant adhesion, and thermal shock resistance).

[0007] As a result of diligent research, 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 has the following configuration: [1] A resin composition containing a polyolefin resin (A), an acid-modified polyolefin resin (B), a styrene-isobutylene-styrene block copolymer (C), an adhesion promoter (D), and a filler (E), wherein the polyolefin resin (A) contains: (A-1) a polypropylene resin, (A-2) a propylene-α-olefin copolymer having a tensile elongation of 1000% or more, and (A-3) a propylene-α-olefin copolymer having a tensile elongation of 300% or more and less than 1000%, and when the total amount of (A-1), (A-2), and (A-3) is 100% by mass, the content of (A-1) is [a1]% by mass, the content of (A-2) is [a2]% by mass, and the content of (A-3) is [a3]% by mass, A resin composition in which, in a coordinate system (A-1 content, A-2 content, A-3 content) where the contents of (A-1), (A-2), and (A-3) are the sides of a triangular diagram, a1, a2, and a3 lie within a region (including points on the boundary lines) enclosed by the following five lines: line O1, line P1, line Q1, line R1, and line S1. Line O1: A line passing through the point (30 mass%, 43 mass%, 27 mass%) and the point (43 mass%, 30 mass%, 27 mass%). Line P1: A line passing through the point (43 mass%, 30 mass%, 27 mass%) and the point (43 mass%, 17 mass%, 40 mass%). Line Q1: A line passing through the point (43 mass%, 17 mass%, 40 mass%) and the point (18.5 mass%, 18.5 mass%, 63 mass%). Straight line R1: A straight line passing through the points (18.5 mass%, 18.5 mass%, 63 mass%) and (17 mass%, 43 mass%, 40 mass%). Straight line S1: A straight line passing through the points (17 mass%, 43 mass%, 40 mass%) and (30 mass%, 43 mass%, 27 mass%). The content in the above straight lines is expressed in the order of (A-1 content, A-2 content, A-3 content).

[0008] [2] The resin composition according to [1], wherein in a total of 100 parts by mass of the polyolefin resin (A), the acid-modified polyolefin resin (B), the styrene-isobutylene-styrene block copolymer (C), and the adhesion promoter (D), the styrene-isobutylene-styrene block copolymer (C) is 8 to 27 parts by mass, the adhesion promoter (D) is 8 to 27 parts by mass, and the filler (E) is 1 to 13 parts by mass with respect to the total of 100 parts by mass, and the filler (E) is in the form of a plate.

[0009] [3] The resin composition according to [1] or [2], wherein the melting point of the acid-modified polyolefin resin (B) is 100°C or higher. [4] The resin composition according to any one of [1] to [3], wherein the styrene content in 100% by mass of the styrene-isobutylene-styrene block copolymer (C) is 10 to 30% by mass. [5] The resin composition according to any one of [1] to [4], wherein the hydroxyl value of the adhesion promoter (D) is 1 to 100 mg KOH / g. [6] The resin composition according to any one of [1] to [5], wherein, in a total of 100 parts by mass of the polyolefin resin (A), the acid-modified polyolefin resin (B), the styrene-isobutylene-styrene block copolymer (C), and the adhesion promoter (D), the content of the polyolefin resin (A) is 38 to 70 parts by mass, and the content of the acid-modified polyolefin resin (B) is 1 to 17 parts by mass.

[0010] [7] The resin composition according to any one of [1] to [6], wherein the (A-1) polypropylene resin is a propylene homopolymer, the (A-2) is at least one selected from the group consisting of propylene-butene copolymer, propylene-heptene copolymer, propylene-hexene copolymer, propylene-octene copolymer, and propylene-ethylene-butene copolymer, and the (A-3) is at least one selected from the group consisting of propylene-ethylene copolymer, propylene-butene copolymer, propylene-heptene copolymer, propylene-hexene copolymer, propylene-octene copolymer, and propylene-ethylene-butene copolymer.

[0011] [8] The resin composition according to [1] to [7], wherein the melt flow rates of (A-1), (A-2), and (A-3) are each 2 to 60 g / 10 min.

[0012] [9] The resin composition according to any one of [1] to [8], wherein the acid-modified polyolefin resin (B) is at least one selected from the group consisting of ethylene-vinyl acetate-maleic anhydride terpolymer, ethylene-ethyl acrylate-maleic anhydride terpolymer, maleic anhydride graft-modified polypropylene, and maleic anhydride graft-modified propylene-α-olefin copolymer.

[0013]

[10] The resin composition according to any one of [1] to [9], wherein the adhesion agent (D) is at least one selected from the group consisting of phenol compounds, xylene-modified phenol resins, terpene-modified phenol resins, and hydrogenated terpene-modified phenol resins.

[0014]

[11] The resin composition according to any one of [1] to

[10] , wherein the filler (E) is at least one selected from the group consisting of glass beads, calcium carbonate, kaolin, talc, clay, glass fibers, and carbon fibers.

[0015]

[12] A hot melt adhesive composition containing the resin composition described in any of [1] to

[11] .

[0016] The resin composition of the present invention has melt-fluid properties suitable for low-pressure molding and exhibits excellent adhesion, heat-resistant adhesion, and thermal shock resistance to electrical and electronic components. Furthermore, it has low water vapor permeability and exhibits high water vapor barrier properties. Therefore, by using the resin composition of the present invention as a sealing material for products requiring high waterproofness, it is possible to efficiently manufacture sealants that meet predetermined water vapor barrier specifications. In particular, the resin composition of the present invention is applicable as a hot-melt adhesive and contributes to maintaining its sealing function even in high-temperature environments, making it suitable for sealing electrical and electronic components.

[0017] Figure 1 is a triangular chart showing preferred ranges for components (A-1) to (A-3) in the resin composition of the present invention. Figure 2 shows a schematic diagram of a chart measured by a differential scanning calorimetry analyzer.

[0018] One embodiment of the present invention will be described in detail below. However, the present invention is not limited thereto, and can be implemented in various modified forms within the scope described.

[0019] <Polyolefin Resin (A)> (Component (A)) In the resin composition of this disclosure, polyolefin resin (A) is a base resin that forms the basic framework of the composition, and in particular, by balancing the following three components (A-1) to (A-3), it contributes to achieving a high level of adhesion (sometimes called room temperature adhesion), heat-resistant adhesion (sometimes called high-temperature adhesion), water vapor barrier properties, and thermal shock resistance. The polyolefin resin (A) of this disclosure contains the following three components: (A-1) Polypropylene resin (sometimes simply referred to as (A-1)) (A-2) Propylene-α-olefin copolymer with a tensile elongation of 1000% or more (sometimes simply referred to as (A-2)) (A-3) Propylene-α-olefin copolymer with a tensile elongation of 300% or more and less than 1000% (sometimes simply referred to as (A-3)) In this disclosure, polyolefin resin (A) refers to a polyolefin resin that has not been acid-modified, unlike the acid-modified polyolefin resin (B) described later.

[0020] <Polypropylene Resin (A-1)> (Component (A-1)) Polypropylene resin (A-1) contributes mainly to improving water vapor barrier properties and heat-resistant adhesion at high temperatures (e.g., 120°C) by increasing the crystallinity of the resin composition. (A-1) is preferably a propylene homopolymer, but may also be a copolymer mainly composed of propylene. If it is a copolymer, the content of copolymer components other than propylene, such as α-olefins, is preferably 1 mol% or less. Considering the improvement of crystallinity, random copolymer polypropylene is preferred as the copolymer, and examples of α-olefins are listed in (A-2) below, among which ethylene and 1-butene are particularly good.

[0021] <Propylene-α-olefin copolymer (A-2)> (Component (A-2)) The propylene-α-olefin copolymer (A-2) imparts flexibility to the resin composition and contributes mainly to improving adhesion at room temperature (25°C). (A-2) has a tensile elongation (measured on a No. 3 dumbbell piece prepared according to JIS K 6251:2017 at a tensile speed of 500 mm / min and an ambient temperature of 25°C) of 1000% or more, preferably 1100% or more, and more preferably 1200% or more. Furthermore, the tensile elongation of (A-2) is preferably 2000% or less, more preferably 1900% or less, and even more preferably 1800% or less. When the tensile elongation of (A-2) is above the above lower limit, its ability to follow substrate deformation increases, contributing to improved room temperature adhesion.

[0022] (A-2) is a copolymer mainly composed of propylene units, copolymerized with one or more types of α-olefins. In one embodiment, it is preferable for this copolymer to be a random copolymer in which α-olefins are randomly introduced into the propylene chain, in order to effectively impart flexibility. Being mainly composed of propylene units means that 50 mol% or more of the total constituent components of (A-2) are propylene units, preferably 55 mol% or more and 85 mol% or less, and more preferably 60 mol% or more and 80 mol% or less. The α-olefin has a carbon number of preferably 2 or more, more preferably 3 or more, preferably 10 or less, more preferably 8 or less, even more preferably 6 or less, and even more preferably 5 or less. Copolymers with α-olefins that satisfy the preferred carbon number contribute to improving the flexibility and adhesion of the resin composition. Specific examples of α-olefins include linear α-olefins such as ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, and 1-decene; and branched α-olefins such as 4-methyl-1-pentene.

[0023] In one embodiment, from the viewpoint of balancing flexibility and adhesion, it is preferable that (A-2) satisfies the following melting point. The melting point of (A-2) is preferably 120°C or higher and 180°C or lower, more preferably 130°C or higher and 170°C or lower, and even more preferably 140°C or higher and 170°C or lower.

[0024] Specific resin types for (A-2) include binary copolymers such as propylene-ethylene copolymer, propylene-butene copolymer, propylene-pentene copolymer, propylene-hexene copolymer, propylene-heptene copolymer, propylene-octene copolymer, and propylene-decene copolymer; and ternary copolymers such as propylene-ethylene-butene copolymer. Particularly from the viewpoint of adhesion, it is preferable to include at least one resin selected from the group consisting of propylene-butene copolymer, propylene-heptene copolymer, propylene-hexene copolymer, propylene-octene copolymer, and propylene-ethylene-butene copolymer. Furthermore, from the viewpoint of achieving an even higher level of both room-temperature adhesion and heat-resistant adhesion, propylene-ethylene-butene copolymer is preferred. (A-2) may be a commercially available product, for example, the "Tafmer PN" series manufactured by Mitsui Chemicals, Inc.

[0025] <Propylene-α-olefin copolymer (A-3)> (Component (A-3)) Propylene-α-olefin copolymer (A-3) contributes to improving the mechanical properties at high temperatures, particularly adhesion at high temperatures, while maintaining the flexibility of the resin composition. (A-3) has a tensile elongation (measured on a No. 3 dumbbell piece prepared according to JIS K 6251:2017 at a tensile speed of 500 mm / min and an ambient temperature of 25°C) of 300% or more and less than 1000%, preferably 400% or more and 900% or less, and more preferably 500% or more and 800% or less. The tensile strength of (A-3) within the above range is effective in improving adhesion, and in particular contributes to improving high-temperature adhesion and thermal shock resistance.

[0026] (A-3) is a copolymer mainly composed of propylene units, copolymerized with one or more types of α-olefins. In one embodiment, this copolymer is preferably a random copolymer, which is preferable for maintaining flexibility while ensuring mechanical properties at high temperatures, i.e., for balancing both properties. Being mainly composed of propylene units means that 50 mol% or more of the total constituent components of (A-3) are propylene units, preferably 80 mol% or more and 99 mol% or less, more preferably more than 80 mol% and 98 mol% or less, even more preferably more than 85 mol% and 97 mol% or less, and even more preferably 90 mol% or more and 96 mol% or less. In one embodiment, in order to exhibit the desired effect, it is preferable that the propylene component content of (A-2) and (A-3) does not overlap. The α-olefin preferably has 2 or more carbon atoms, preferably 10 or less, more preferably 8 or less, even more preferably 6 or less, and even more preferably 4 or less. Copolymers with α-olefins that satisfy the preferred number of carbon atoms contribute to improving the flexibility and high-temperature adhesion of the resin composition. Specific examples of α-olefins include linear α-olefins such as ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, and 1-decene, and branched α-olefins such as 4-methyl-1-pentene. Short-chain α-olefins such as ethylene and 1-butene are preferred when considering heat resistance.

[0027] In one embodiment, from the viewpoint of balancing mechanical strength at high temperatures and high-temperature adhesion, it is preferable that (A-3) satisfies the following melting point. The melting point of (A-3) is preferably 100°C or higher and 150°C or lower, more preferably 110°C or higher and 140°C or lower.

[0028] Specific resin types for (A-3) include binary copolymers such as propylene-ethylene copolymer, propylene-butene copolymer, propylene-pentene copolymer, propylene-hexene copolymer, propylene-heptene copolymer, and propylene-octene copolymer; and ternary copolymers such as propylene-ethylene-butene copolymer. Particularly from the viewpoint of high-temperature adhesion, it is preferable to include at least one resin selected from the group consisting of propylene-ethylene copolymer, propylene-butene copolymer, propylene-heptene copolymer, propylene-hexene copolymer, propylene-octene copolymer, and propylene-ethylene-butene copolymer. Furthermore, from the viewpoint of high-temperature adhesion (e.g., 120°C adhesion), propylene-ethylene copolymer is preferred. (A-3) may be a commercially available product, for example, the "Wintec" series manufactured by Nippon Polypropylene Co., Ltd.

[0029] Polyolefin resin (A) In one embodiment, from the viewpoint of further improving the effects of the present disclosure, it is preferable that the polyolefin resin (A) satisfies one or more of the following conditions: Melt flow rate (MFR) The MFR of the polyolefin resin (A) (JIS K 7210-1:2014, test temperature 190°C, nominal load 2.16 kg) is preferably 2 g / 10 min or more and 60 g / 10 min or less, more preferably 3 g / 10 min or more and 60 g / 10 min or less, even more preferably 4 g / 10 min or more and 50 g / 10 min or less, and even more preferably 5 g / 10 min or more and 20 g / 10 min or less. Adjusting the MFR improves the fluidity during molding and suppresses excessive softening, contributing to improved mechanical properties. In one embodiment, it is preferable that the MFRs of (A-1), (A-2), and (A-3) that constitute the polyolefin resin (A) are each within the above ranges.

[0030] In one embodiment, the melting point of the polyolefin resin (A) is preferably 90°C or higher and 210°C or lower, more preferably 100°C or higher and 190°C or lower, with a lower limit of 110°C or higher, and even more preferably 120°C or higher. In one embodiment, adjusting the melting point contributes to the heat resistance required when used as a hot melt adhesive, and can enable rapid melting while suppressing thermal degradation during molding. In one embodiment, it is preferable that the melting points of (A-1), (A-2), and (A-3) constituting the polyolefin resin (A) are each within the above range.

[0031] Composition of Polyolefin Resin (A) In one embodiment, the sum of the three components (A-1), (A-2), and (A-3) relative to 100% by mass of the total amount of polyolefin resin (A) is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and most preferably 100% by mass. In one embodiment, the polyolefin resin (A) may contain as a remainder other than the above-mentioned polyolefin resins, such as cyclic olefin copolymers (COC) and cyclic olefin polymers (COP), as long as it does not hinder the effects of the present disclosure, but it is preferable to have as little as possible.

[0032] Content in the resin composition In one embodiment, in a total of 100 parts by mass of polyolefin resin (A), acid-modified polyolefin resin (B), styrene-isobutylene-styrene block copolymer (C), and adhesion promoter (D), the content of polyolefin resin (A) is preferably 38 parts by mass or more and 70 parts by mass or less, more preferably 40 parts by mass or more and 68 parts by mass or less, even more preferably 42 parts by mass or more and 63 parts by mass or less, with an even more preferable lower limit of 48 parts by mass or more. By adjusting the content of polyolefin resin (A) in the resin composition, the water vapor barrier properties and thermal shock resistance can be further improved.

[0033] In the resin composition of this disclosure, the blending ratio of the three components (A-1), (A-2), and (A-3) constituting the polyolefin resin (A) is appropriately adjusted to achieve a high level of both water vapor barrier properties, room temperature adhesion, and high-temperature adhesion. Specifically, with respect to 100% by mass of the total amount of (A-1), (A-2), and (A-3), the content of (A-1) is a1 (by mass%), the content of (A-2) is a2 (by mass%), and the content of (A-3) is a3 (by mass%), and the contents of (A-1), (A-2), and (A-3) are represented by coordinate axes (A-1 content, A-2 content, A-3 content) on a triangular diagram, the composition (a1, a2, a3) of the polyolefin resin (A) must lie within the region enclosed by five straight lines: O1, P1, Q1, R1, and S1 (including points on the boundary lines).

[0034] Here, lines O1, P1, Q1, R1, and S1 are defined as lines passing through the following two points, respectively. The coordinates of the lines are in the order of (A-1 content, A-2 content, A-3 content). Straight line O1: Point 1 (30 (mass %), 43 (mass %), 27 (mass %)) and point 2 (43 (mass %), 30 (mass %), 27 (mass %)) Straight line P1: Point 1 (43 (mass %), 30 (mass %), 27 (mass %)) and point 2 (43 (mass %), 17 (mass %), 40 (mass %)) Straight line Q1: Point 1 (43 (mass %), 17 (mass %), 40 (mass %)) and point 2 (18.5 (mass %), 18.5 (mass %), 63 (mass %)) Straight line R1: Point 1 (18.5 (mass %), 18.5 (mass %), 63 (mass %)) and point 2 (17 (mass %), 43 (mass %), 40 (mass %)) Straight line S1: Point 1 (17 (mass%), 43 (mass%), 40 (mass%)) and point 2 (30 (mass%), 43 (mass%), 27 (mass%))

[0035] By satisfying the above specific composition range, the polyolefin resin (A) can maintain all of its water vapor barrier property, normal temperature adhesiveness, and high temperature adhesiveness at a high level in a well-balanced manner. In one embodiment, it is assumed that the electric and electronic components are used in various environments and need to have more severe resistance. For example, since they are exposed to a high temperature environment due to heat generation during charge and discharge, etc., there is a demand for a sealing resin composition that exhibits high adhesive strength even in environments of about 25°C and 120°C. Therefore, the resin composition of the present disclosure that can achieve good balance in all of the water vapor barrier property, 25°C adhesive strength, and 120°C adhesive strength is suitable as a sealing resin composition for which such characteristics are required.

[0036] The above preferable range will be described using the triangular chart shown in FIG. 1. The three sides of the triangular chart respectively indicate the coordinate axes of the content a1 (mass %) of (A-1), the content a2 (mass %) of (A-2), and the content a3 (mass %) of (A-3). Here, when the coordinates inside the triangular chart are expressed in the order of (A-1 content, A-2 content, A-3 content), five coordinates (30, 43, 27), (43, 30, 27), (43, 17, 40), (18.5, 18.5, 63), and (17, 43, 40) are shown in the triangular chart. And the inner range (including the points on the boundary line) surrounded by the five straight lines O1, P1, Q1, R1, and S1 that connect these five points in order indicates the composition range that can possess the water vapor barrier property, 25°C adhesive strength, and 120°C adhesive strength in a well-balanced manner.

[0037] The composition range surrounded by the above five straight lines is preferably set to a narrower range from the viewpoint of further improving the characteristics. Adjusting the composition to a suitable range contributes more to the improvement of the effect. The straight line O1 is preferably the straight line O2, and more preferably the straight line O3. Straight line O2: A straight line passing through point 1 (30 (mass %), 42 (mass %), 28 (mass %)) and point 2 (42 (mass %), 30 (mass %), 28 (mass %)). Straight line O3: A straight line passing through point 1 (30 (mass %), 41 (mass %), 29 (mass %)) and point 2 (41 (mass %), 30 (mass %), 29 (mass %)).

[0038] The straight line P1 is preferably the straight line P2, more preferably the straight line P3. The straight line P2: The straight line passing through point 1 (42 (mass %), 30 (mass %), 28 (mass %)) and point 2 (42 (mass %), 18 (mass %), 40 (mass %)) The straight line P3: The straight line passing through point 1 (41 (mass %), 30 (mass %), 29 (mass %)) and point 2 (41 (mass %), 19 (mass %), 40 (mass %))

[0039] The straight line Q1 is preferably the straight line Q2, more preferably the straight line Q3. The straight line Q2: The straight line passing through point 1 (42 (mass %), 18 (mass %), 40 (mass %)) and point 2 (19 (mass %), 19 (mass %), 62 (mass %)) The straight line Q3: The straight line passing through point 1 (41 (mass %), 19 (mass %), 40 (mass %)) and point 2 (19.5 (mass %), 19.5 (mass %), 61 (mass %))

[0040] The straight line R1 is preferably the straight line R2, more preferably the straight line R3. The straight line R2: The straight line passing through point 1 (19 (mass %), 19 (mass %), 62 (mass %)) and point 2 (18 (mass %), 42 (mass %), 40 (mass %)) The straight line R3: The straight line passing through point 1 (19.5 (mass %), 19.5 (mass %), 61 (mass %)) and point 2 (19 (mass %), 41 (mass %), 40 (mass %))

[0041] The straight line S1 is preferably the straight line S2, more preferably the straight line S3. The straight line S2: The straight line passing through point 1 (18 (mass %), 42 (mass %), 40 (mass %)) and point 2 (30 (mass %), 42 (mass %), 28 (mass %)) The straight line S3: The straight line passing through point 1 (19 (mass %), 41 (mass %), 40 (mass %)) and point 2 (30 (mass %), 41 (mass %), 29 (mass %))

[0042] Furthermore, the content of each component is preferably within the following ranges. The content a1 of (A-1) is preferably 17% by mass or more, more preferably 18% by mass or more, even more preferably 19% by mass or more, and particularly preferably 20% by mass or more, from the viewpoint of increasing the crystallinity of the resin composition and obtaining good water vapor barrier properties. On the other hand, from the viewpoint of ensuring the flexibility of the resin composition and obtaining good 25°C adhesive strength, it is preferably 43% by mass or less, more preferably 42% by mass or less, even more preferably 41% by mass or less, and particularly preferably 40% by mass or less.

[0043] The content of (A-2) a2 is preferably 17% by mass or more, more preferably 18% by mass or more, even more preferably 19% by mass or more, and particularly preferably 20% by mass or more, from the viewpoint of allowing the resin composition to easily follow the deformation of the substrate during the peel test and obtaining good 25°C adhesive strength. On the other hand, from the viewpoint of maintaining the crystallinity of the resin composition and maintaining good mechanical properties, water vapor barrier properties, and 120°C adhesive strength at high temperatures, it is preferably 43% by mass or less, more preferably 42% by mass or less, even more preferably 41% by mass or less, and particularly preferably 40% by mass or less.

[0044] The content of (A-3) a3 is preferably 27% by mass or more, more preferably 28% by mass or more, even more preferably 29% by mass or more, and particularly preferably 30% by mass or more, from the viewpoint of improving mechanical properties under heat while maintaining flexibility and balancing adhesive strength at 25°C and 120°C. On the other hand, from the viewpoint of maintaining the crystallinity of the resin composition and obtaining good water vapor barrier properties, it is preferably 63% by mass or less, more preferably 62% by mass or less, even more preferably 61% by mass or less, and particularly preferably 60% by mass or less.

[0045] In one embodiment, the lines O1, P1, Q1, R1, and S1 in the triangular diagram of Figure 1 can be expressed by the following equations, and the desired effect can be achieved by satisfying all of the following equations (1) to (5). (1) 0 < [a1] ≤ 43 (2) 0 < [a2] ≤ 43 (3) [a3] ≥ 27 (4) 49[a1] + 3[a2] ≥ 962 (5) 3[a1] + 49[a2] ≥ 962 When the total amount of (A-1), (A-2), and (A-3) is 100% by mass, the content of (A-1) is [a1]% by mass, the content of (A-2) is [a2]% by mass, and the content of (A-3) is [a3]% by mass.

[0046] Formula (1) 0 < [a1] ≤ 43 Formula (1) corresponds to the line P1 in the triangular diagram and defines the content of (A-1) [a1] mass%. The preferred range for the upper and lower limits of Formula (1) is as a1 above, preferably 17 mass% or more, more preferably 18 mass% or more, even more preferably 19 mass% or more, particularly preferably 20 mass% or more, preferably 43 mass% or less, more preferably 42 mass% or less, even more preferably 41 mass% or less, and particularly preferably 40 mass% or less.

[0047] Formula (2) 0 < [a2] ≤ 43 Formula (2) corresponds to the line S1 in the triangular diagram and defines the content [a2] (mass%) of (A-2). The preferred range for the upper and lower limits of Formula (2) is as a2 above, preferably 17% by mass or more, more preferably 18% by mass or more, even more preferably 19% by mass or more, particularly preferably 20% by mass or more, more preferably 42% by mass or less, even more preferably 41% by mass or less, and particularly preferably 40% by mass or less.

[0048] Formula (3) [a3] ≥ 27 Formula (3) corresponds to the line O1 in the triangular diagram and defines the content [a3] (mass%) of (A-3). The preferred range for the upper and lower limits of Formula (3) is as a3 above, more preferably 28 mass% or more, even more preferably 29 mass% or more, particularly preferably 30 mass% or more, preferably 63 mass% or less, more preferably 62 mass% or less, even more preferably 61 mass% or less, and particularly preferably 60 mass% or less.

[0049] Equation (4) 49[a1] + 3[a2] ≥ 962 Equation (5) 3[a1] + 49[a2] ≥ 962 Equations (4) and (5) correspond to lines R1 and Q1 in the triangular diagram, respectively, and define the combined lower limit balance of the content of (A-1) and (A-2). The preferred range of the upper and lower limits of Equation (4) is expressed by the following equations corresponding to lines R2 and R3: (4-1) 23[a1] + [a2] ≥ 456 (corresponding to R2) (4-2) 43[a1] + [a2] ≥ 858 (corresponding to R3) The preferred range of the upper and lower limits of Equation (5) is expressed by the following equations corresponding to lines Q2 and Q3: (5-1) [a1] + 23[a2] ≥ 456 (corresponding to Q2) (5-2) [a1] + 43[a2] ≥ 858 (corresponding to Q3)

[0050] <Acid-modified polyolefin resin (B)> (Component (B)) Acid-modified polyolefin resin (B) functions as a dispersant (compatibility agent). Specifically, it enhances the compatibility of polyolefin resin (A) with other components of different polarity, namely styrene-isobutylene-styrene block copolymer (C), adhesion promoter (D), and filler (E), and uniformly disperses them throughout. This good dispersibility allows the resin composition as a whole to exhibit a well-balanced combination of the desired adhesive properties, thermal shock resistance, and water vapor barrier properties.

[0051] The acid-modified polyolefin resin (B) is not particularly limited as long as it is a resin having a polyolefin segment and a carboxylic acid segment. Specific examples include the following, which may be used individually or in combination of two or more: ethylene-unsaturated carboxylic acid copolymers such as ethylene-vinyl acetate-maleic anhydride terpolymer and ethylene-ethyl acrylate-maleic anhydride terpolymer; and unsaturated carboxylic acid graft-modified polyolefin resins such as maleic anhydride graft-modified polypropylene and maleic anhydride graft-modified propylene-α-olefin copolymer. Of these, unsaturated carboxylic acid graft-modified polyolefin resins are preferred, and maleic anhydride is more preferred as the unsaturated carboxylic acid used for graft modification.

[0052] In one embodiment, it is also preferable that the acid-modified polyolefin resin (B) satisfies the following melting point and / or content. The melting point of the acid-modified polyolefin resin (B) is preferably 100°C or higher and 160°C or lower, more preferably 110°C or higher and 150°C or lower, and a further preferable lower limit may be 120°C or higher. Adjusting the melting point of the acid-modified polyolefin resin (B) can further improve high-temperature adhesion and fluidity during molding.

[0053] The content of the acid-modified polyolefin resin (B) is preferably 1 part by mass or more and 17 parts by mass or less, more preferably 3 parts by mass or more and 15 parts by mass or less, even more preferably 5 parts by mass or more and 13 parts by mass or less, and even more preferably 10 parts by mass or less, in 100 parts by mass of the total of the polyolefin resin (A), acid-modified polyolefin resin (B), styrene-isobutylene-styrene block copolymer (C), and adhesion promoter (D). By adjusting the content of the acid-modified polyolefin resin (B), the dispersibility and mechanical properties of each component can be further improved.

[0054] <Styrene-isobutylene-styrene block copolymer (C)> (Component (C)) Styrene-isobutylene-styrene block copolymer (C) functions as a stress-relieving agent, contributing to improved thermal shock resistance of resin compositions and to achieving compatibility between thermal shock resistance and other physical properties. It also contributes to improved adhesion at room temperature (25°C) by relieving the stress generated during delamination.

[0055] In one embodiment, the styrene-isobutylene-styrene block copolymer (C) is a block copolymer composed of a styrene block and an isobutylene block, but a triblock structure having styrene blocks at both ends is preferred from the viewpoint of water vapor barrier properties and thermal shock resistance.

[0056] Styrene Content In one embodiment, the styrene content in 100% by mass of the styrene-isobutylene-styrene block copolymer (C) is preferably 10% by mass or more and 30% by mass or less, more preferably 13% by mass or more and 25% by mass or less, and even more preferably 15% by mass or more and 20% by mass or less. Adjusting the styrene content further improves high-temperature adhesion and thermal shock resistance.

[0057] In one embodiment, the content of styrene-isobutylene-styrene block copolymer (C) is preferably 8 parts by mass or more and 27 parts by mass or less, more preferably 10 parts by mass or more and 25 parts by mass or less, even more preferably 12 parts by mass or more and 24 parts by mass or less, particularly preferably 15 parts by mass or more and 23 parts by mass or less, and most preferably 18 parts by mass or more and 22 parts by mass or less, based on 100 parts by mass of the total of polyolefin resin (A), acid-modified polyolefin resin (B), styrene-isobutylene-styrene block copolymer (C), and adhesion promoter (D). By adjusting the content of styrene-isobutylene-styrene block copolymer (C), high-temperature adhesion and thermal shock resistance can be further improved.

[0058] In one embodiment, the melt flow rate (MFR) (JIS K 7210-1:2014, test temperature 230°C, nominal load 2.16 kg) of the styrene-isobutylene-styrene block copolymer (C) is preferably 0.1 g / 10 min or more and 9 g / 10 min or less. Adjusting the MFR can further improve fluidity (moldability) and adhesion.

[0059] In one embodiment, the styrene-isobutylene-styrene block copolymer (C) may be a commercially available product, for example, the "SIBSTAR" series manufactured by Kaneka Corporation. In one embodiment, the resin composition may use two or more styrene-isobutylene-styrene block copolymers (C) that differ in at least one of the group consisting of block structure, styrene content, and MFR, but it is preferable that each styrene-isobutylene-styrene block copolymer is within the above range.

[0060] <Adhesion-improving agent (D)> (Component (D)) Adhesion-improving agent (D) contributes to improving the adhesion between the resin composition and the substrate, and also contributes to improving moldability by adjusting the melt viscosity of the entire resin composition to improve fluidity.

[0061] In one embodiment, the adhesion promoter (D) is preferably a phenol compound or various modified phenol resins. Specifically, examples include phenol compounds, xylene-modified phenol resins, terpene-modified phenol resins, and hydrogenated terpene-modified phenol resins, and one or more may be used in combination. Of these, xylene-modified phenol resins and / or terpene-modified phenol resins, which contribute to improving compatibility with the polyolefin resin (A), are preferred.

[0062] In one embodiment, the adhesion promoter (D) may also satisfy the following physical properties. Hydroxyl value In one embodiment, the adhesion promoter (D) preferably has hydroxyl groups in order to improve adhesion by increasing wettability to the substrate. The hydroxyl value (potentiometric titration method, in accordance with JIS K 0070:1992) is preferably 1 mg KOH / g or more and 100 mg KOH / g or less, more preferably 30 mg KOH / g or more and 90 mg KOH / g or less, even more preferably 50 mg KOH / g or more and 80 mg KOH / g or less, and even more preferably the upper limit may be 70 mg KOH / g or less. Adjusting the hydroxyl value improves adhesion while contributing to suppressing a decrease in water vapor barrier properties (moisture permeability).

[0063] The content of the adhesion promoter (D) is preferably 8 parts by mass or more and 27 parts by mass or less, more preferably 18 parts by mass or more and 26 parts by mass or less, and even more preferably 20 parts by mass or more and 25 parts by mass or less, in 100 parts by mass of the total of the polyolefin resin (A), acid-modified polyolefin resin (B), styrene-isobutylene-styrene block copolymer (C), and adhesion promoter (D), and the lower limit may be 22 parts by mass or more. Adjusting the content of the adhesion promoter (D) contributes to improving adhesion and also contributes to suppressing the decrease in adhesion at room temperature due to a decrease in flexibility or embrittlement of the resin composition.

[0064] <Filler (E)> (Component (E)) Filler (E) contributes to improving the water vapor barrier properties of the resin composition by complicating the pathways through which water vapor can penetrate when dispersed within the resin composition layer.

[0065] The filler (E) is not particularly limited and may be various inorganic fillers or fibrous fillers. Specifically, examples include inorganic fillers such as glass beads, calcium carbonate, kaolin, talc, and clay; and fibrous fillers such as glass fibers and carbon fibers. In one embodiment, the particle size (D50) of the filler (E) may be, for example, 1 to 50 μm. The particle size (D50) can be measured, for example, by laser diffraction or dynamic light scattering.

[0066] In one embodiment, from the viewpoint of effectively suppressing water vapor permeation, the filler (E) is preferably in the form of a plate. The plate-shaped filler is oriented within the resin and functions as a physical barrier against the intrusion of water molecules, contributing to improved water vapor barrier properties. Examples of plate-shaped fillers include talc, kaolin, montmorillonite, and mica. Plate-shaped refers to a shape like a plate in which the height is extremely small compared to the width and depth of the filler. For example, the aspect ratio (major axis / minor axis) of the plate-shaped filler (E) is preferably 3 to 500, more preferably 5 to 450, even more preferably 10 to 400, even more preferably 20 to 350, particularly preferably 50 to 300, and most particularly preferably 100 to 200. The aspect ratio of the filler can be determined by automatically measuring the area of ​​an image obtained by observing it with an electron microscope. By adjusting the aspect ratio of the plate-shaped filler (E), the water vapor barrier properties, mechanical properties, and dispersibility of the filler can be further improved.

[0067] The content of filler (E) is preferably 1 to 13 parts by mass, more preferably 2 to 10 parts by mass, and even more preferably 4 to 8 parts by mass, based on 100 parts by mass of the total of polyolefin resin (A), acid-modified polyolefin resin (B), styrene-isobutylene-styrene block copolymer (C), and adhesion promoter (D). By adjusting the content of filler (E), the water vapor barrier properties and adhesion can be further improved.

[0068] <Resin Composition> The resin composition of this disclosure contains the above components (A), (B), (C), (D), and (E). The resin composition of this disclosure has a melt viscosity of preferably 5 dPa·s or more and less than 3000 dPa·s, more preferably 10 dPa·s or more and less than 2500 dPa·s, measured at 220°C, with the lower limit more preferably 30 dPa·s or more, and even more preferably 50 dPa·s or more. Adjusting the melt viscosity contributes to molding at low injection pressure (e.g., 0.1 to 20 MPa) and contributes to improved adhesion by maintaining the cohesive force of the resin. In this disclosure, the above melt viscosity is the value measured under the following conditions. That is, after drying the resin composition to a moisture content of 0.1% or less, it was measured using a flow tester (Shimadzu Corporation, CFT-500C). After stabilizing the resin composition by heating and holding it at 220°C, it was passed through a die with a pore size of 1.0 mm and a thickness of 10 mm, and measured at 98 N / cm ２ The viscosity values ​​were recorded when a load was applied.

[0069] Optional Additives In addition to the essential components mentioned above, the resin composition of the present invention may contain various optional additives as shown below, to the extent that they do not impair the effects of the present invention. Antioxidants Antioxidants prevent oxidation of the polyolefin resin (A) and contribute to improving long-term durability at high temperatures. Specifically, the following antioxidants are mentioned. Hindered phenol antioxidants 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-hydroxybenzenepropanoic acid, pentaerythrityltetrakis(3,5-di-t-butyl-4- Examples include 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, and 1,3,5-trimethyl-2,4,6-tris(3',5'-di-t-butyl-4'-hydroxybenzyl)benzene.As phosphorus-based antioxidants, 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, isodecylphosphite, isodecylphenylphosphite, diphenyl 2-ethylhexylphosphite, dinonylphenylbis(no Examples include nylphenyl) 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'-methylenebis(4,6-di-t-butylphenyl)2-ethylhexyl phosphite, and bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite. Examples of thioether-based antioxidants 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. These can be used individually or in combination.

[0070] The antioxidant content is preferably 0.1 parts by mass or more and 1 part by mass or less, with a lower limit of more preferably 0.2 parts by mass or more, and even more preferably 0.3 parts by mass or more, in 100 parts by mass of the total of the polyolefin resin (A), acid-modified polyolefin resin (B), styrene-isobutylene-styrene block copolymer (C), and adhesion promoter (D). Adjusting the antioxidant content may contribute to improved long-term durability at high temperatures and improved adhesion.

[0071] Light stabilizers contribute to improving the weather resistance of resin compositions. 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 per 100% by mass of the entire resin composition (components (A) to (E)). 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.

[0072] Other Resins The resin compositions of this disclosure may contain other resins that do not fall under any of the above components (A) to (E). Specific examples include other resins such as polyamide, polycarbonate, acrylic, and ethylene vinyl acetate. Other Additives The resin compositions of this disclosure may contain curing agents such as isocyanate compounds and melamine, pigments such as carbon black and titanium dioxide, and flame retardants such as antimony trioxide and brominated polystyrene, to the extent that they do not impair the effects of this disclosure. By incorporating these components, adhesion, flexibility, durability, etc., may be improved.

[0073] In one embodiment, when various additives are included, the content of polyolefin resin (A) is preferably 30 to 70% by mass, and more preferably 40 to 60% by mass, relative to the total resin composition of the present invention. If the content of polyolefin resin (A) is too low, the excellent water vapor barrier properties and durability inherent in polyolefin resin (A) tend to decrease, and if it is too high, the flexibility and adhesive properties tend to decrease.

[0074] <Method for Manufacturing Resin Composition> The resin composition of the present invention is not particularly limited, but can be manufactured by a general melt-kneading method such as the one shown below. Raw Material Blending and Mixing Process First, the raw materials for the resin composition, such as the above components (A) to (E) and various additives such as antioxidants which may be blended as needed, are weighed out in predetermined blending ratios. Next, these raw materials are dry-blended (pre-mixed) uniformly using a mixer such as a Henschel mixer or a tumbler mixer.

[0075] In the melt-mixing process, the pre-mixed raw materials are supplied to a twin-screw extruder for melt-mixing. The temperature conditions during mixing are set appropriately according to the type of resin used, but for example, the die temperature can be in the range of 160°C to 220°C. Note that the equipment used for mixing is not limited to a twin-screw extruder; known mixing machines such as single-screw extruders, Banbury mixers, and kneaders can also be used.

[0076] At the end of the pelletizing process, the molten resin extruded from the extruder in strand form is cooled in a water tank or the like, and then cut using a pelletizer such as a strand cutter to obtain a pelletized resin composition. The obtained pellets are then supplied to the subsequent molding process.

[0077] <Hot Melt Adhesive Composition> The resin composition of the present invention can be used as a hot melt adhesive composition. It is particularly suitable for use as a sealant for electrical and electronic components that require high levels of waterproofing and moisture resistance. In one embodiment, when this resin composition is used as a sealant, a general low-pressure injection molding (hot melt molding) process can be applied. Preparation stage: The product to be sealed and waterproofed is set in a predetermined mold. Melting stage: For example, using a screw-type hot melt molding applicator, the resin composition according to this disclosure is heated and melted at 180 to 250°C. Injection stage: The molten resin is injected into the mold through an injection nozzle to seal the product. Cooling and demolding stage: After solidification for a predetermined cooling time, it is removed from the mold to obtain a sealed molded product.

[0078] Examples of usable equipment The type of applicator (molding machine) used in the above molding process is not particularly limited, but the following are examples of equipment: IMC-18F9 vertical extrusion molding machine manufactured by Imoto Seisakusho Co., Ltd. STX20, THX5S1VN hybrid small vertical injection molding machine manufactured by Nissei Plastic Industrial Co., Ltd.

[0079] This application claims the benefit of priority under Japanese application No. 2024-167715, filed on 26 September 2024. The entire specification of Japanese application No. 2024-167715 is incorporated herein by reference.

[0080] 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.

[0081] <Measurement of Tensile Elongation> Using a vertical injection molding machine (TH40E, manufactured by Nissei Plastic Industrial Co., Ltd.), injection molding was performed under the following conditions: resin temperature 200°C, injection molding pressure 32 MPa, cooling time 20 seconds, and injection speed 15 mm / second to produce a 100 mm x 100 mm, 2 mm thick flat plate of the resin composition. Next, three dumbbell-shaped test pieces conforming to JIS K6251:2017 were cut out from the obtained flat plate using a punching blade. Then, the test pieces were gripped in a universal material testing machine (Autograph AG-IS, manufactured by Shimadzu Corporation) with a chuck distance of 20 mm, and a tensile test was performed at a tensile speed of 500 mm / min to measure the elongation (%) at fracture.

[0082] <Measurement of Melting Point> Using a differential scanning calorimetry analyzer (Seiko Electronics Industries, Ltd., DSC220 model), 5 mg of the sample (polyolefin resin (A) or acid-modified polyolefin resin (B)) was placed in an aluminum airtight pan and sealed by pressing the lid. The measurement was performed by heating the sample to 230°C at 20°C / min under a nitrogen atmosphere to melt it, and then cooling it to -130°C at 20°C / min using liquid nitrogen and holding it for 5 minutes. Subsequently, the temperature was heated again from -130°C to 230°C at 20°C / min (second heating process), and the DSC curve during this period was measured. In the DSC curve obtained during the second heating process, the point with the lowest endothermic peak (minimum) (marked with an "x" in Figure 2) was defined as the melting point (Tm).

[0083] <Hydroxyl Value> The hydroxyl value (mgKOH / g) of the adhesion agent (D) was measured by potentiometric titration as specified in JIS K 0070:1992.

[0084] <Melting Viscosity> (Fluidity) The melting viscosity was measured using a capillary rheometer (Shimadzu Corporation, Flow Tester CFT-500C) following the procedure below. First, the sample to be measured (compound raw materials or resin composition) was thoroughly dried until the moisture content was 0.1% or less. Next, the dried sample was filled into a cylinder set to a measurement temperature of 220°C and preheated for 1 minute. After preheating, a test pressure of 0.98 MPa (98 N / cm) was applied to the sample via a plunger. ２A pressure is applied, and the molten sample is extruded from the die (inner diameter 1.0 mm, length 10 mm). The melt viscosity (dPa·s) is calculated from the extrusion amount and pressure at this time. Based on the calculated melt viscosity value, the fluidity was evaluated according to the following criteria. Evaluation criteria Good (○): Melt viscosity at 220°C is 5 dPa·s or more and less than 2500 dPa·s (△): Melt viscosity at 220°C is 2500 dPa·s or more and less than 3000 dPa·s (×): Melt viscosity at 220°C is 3000 dPa·s or more

[0085] <Water vapor barrier properties> A film with a thickness of approximately 120 μm was prepared from the resin composition for the test film using a heat press machine (SA-303, manufactured by Tester Sangyo Co., Ltd.). The molding conditions were a temperature of 200°C, a press pressure of 10 MPa, and a press time of 30 seconds. From the obtained film, test pieces conforming to JIS Z0208:1976 (cup method) were cut out using a cutting machine. Moisture permeability measurement Calcium chloride was placed as a desiccant in a jig (moisture permeable cup) specified in JIS Z0208:1976, and the moisture permeable cup sealed with the above test piece was placed in a constant temperature and humidity chamber at a temperature of 25°C and a relative humidity of 90% RH. Samples were taken out and their mass was measured 24 hours, 48 ​​hours, 72 hours, and 96 hours after the start of the test. The period from 24 hours to 96 hours was divided into three measurement intervals: (1) from 24 hours to 48 hours, (2) from 48 hours to 72 hours, and (3) from 72 hours to 96 hours. The permeability was calculated from the mass increase in each interval. The average of the three obtained permeability values ​​was used as the evaluation value (average permeability). The permeability for each interval was calculated using the following formula: Permeability (g / m³) ２ 24h) = (240 × m) / (t × s) m: Mass increase at each measurement interval (mg) t: Time between measurements (h) (24h in this measurement) s: Water permeability area (cm²) ２ (In this measurement, the effective opening area of ​​the vapor permeable cup) Based on the calculated average value (average moisture permeability), the water vapor barrier performance was evaluated according to the following criteria. Evaluation criteria Good (〇): Average moisture permeability of 1.0 g / (m ２ - Less than 24 hours (△): Average moisture permeability is 1.0 g / (m ２ ・24h) or more 1.5g / (m２ - Less than 24 hours (×): Average moisture permeability of 1.5 g / (m²) is unacceptable. ２ ・24 hours or more

[0086] <Adhesion Test (T-Peel Adhesion Strength)> Method for Preparing T-Peel Adhesion Test Specimens Two pieces of 0.1 mm thick aluminum plate (A5052) were cut to dimensions of 40 mm x 25 mm, and the surface was wiped with acetone to degrease and clean it. A film with a thickness of approximately 200 μm was prepared from a resin composition using a heat press machine (SA-303, manufactured by Tester Sangyo Co., Ltd.). The molding conditions were a temperature of 200°C, a press pressure of 6 MPa, and a press time of 10 seconds. Two pieces of the obtained film were cut to dimensions of 20 mm x 25 mm. These two films were stacked and sandwiched between the two aluminum plates to create a laminate (aluminum plate / film / film / aluminum plate). This was set in a heat seal tester (TP-701-B, manufactured by Tester Sangyo Co., Ltd.), and heat-pressed to integrate it under the conditions of a temperature of 220°C, a pressure of 0.4 MPa, and a press time of 30 seconds to obtain a T-peel adhesion test specimen.

[0087] T-Peel Adhesion Strength Test Method A T-peel adhesive test specimen was prepared and subjected to a T-shaped peel test using a tensile testing machine (Shimadzu Autograph AG-IS). Aluminum plates at both ends of the T-peel adhesive test specimen were clamped with chucks, and the specimen was peeled off at a tensile speed of 300 mm / min. Measurements were taken at two temperature environments, 25°C and 120°C, and the strength at the time of peeling (N / 25 mm) was measured as the T-peel adhesive strength. Based on the obtained T-peel adhesive strength, the following criteria were used for evaluation. Evaluation Criteria Good (○): T-peel adhesive strength of 70 N / 25 mm or more is acceptable (△): T-peel adhesive strength of 50 N / 25 mm or more, but less than 70 N / 25 mm is unacceptable (×): T-peel adhesive strength less than 50 N / 25 mm

[0088] <Heat Resistance Impact Test> Method for preparing a heat resistance impact test sample Processing of the base material: As the base material, an aluminum plate (A5052) with dimensions of 40 mm × 30 mm and a thickness of 5 mm was used. A groove with a length of 30 mm, a width of 1 mm, and a depth of 1 mm was machined at one end of the long side of this base material. Next, after subjecting the grooved portion to a blasting treatment to adjust the surface roughness (Rz) to approximately 5 μm, it was degreased and washed with acetone. Injection molding: Next, the processed base material was placed as an insert into the mold. Then, using an injection molding machine (Hybrid small vertical injection molding machine THX5S1VN manufactured by Nissei Plastic Industrial Co., Ltd.), insert molding was performed by filling the resin composition into the grooved portion of the base material. Molding conditions: Temperature 240 °C, mold temperature 90 °C, injection speed 30 mm / s, holding pressure 50 MPa, injection time 10 seconds, holding pressure time 20 seconds. Thus, a heat resistance impact test sample in which the resin composition was integrally adhered to the groove portion of the aluminum base material was prepared.

[0089] Heat resistance impact test method The prepared heat resistance impact test sample was placed in a thermal shock test chamber (TSE - 11 manufactured by Espec Corporation), and a thermal cycle between - 45 °C and 95 °C was repeated

[2000] times. The conditions for one cycle were to hold for 9 minutes in an environment of - 45 °C and then hold for 10 minutes in an environment of 95 °C. After 2000 cycles, the heat resistance impact test sample was visually observed, and the heat resistance impact was evaluated according to the following criteria. Evaluation criteria Good (○): No cracks in the resin composition and no peeling from the aluminum base material are observed. Poor (×): Cracks in the resin composition or peeling from the aluminum base material are observed.

[0090] <Examples and Comparative Examples> The following components (A) to (E) were prepared at the ratios described in Tables 1 and 2. The details of each raw material used are as follows. (A) Polyolefin resin Polyolefin resin (A - 1): J107G manufactured by Prime Polymer Co., Ltd., melting point: 165 °C, density: 0.9 g / cm ３ J107G corresponds to the (A - 1) polypropylene resin in the present invention. Polyolefin resin (A - 2): Toughmer PN - 20300 manufactured by Mitsui Chemicals, Inc., melting point: 160 °C, tensile elongation: 1400%, density: 0.9 g / cm ３PN-20300 corresponds to (A-2) propylene-α-olefin resin in the present invention. Polyolefin resin (A-3): Wintec WSX03 manufactured by Nippon Polypropylene Co., Ltd., melting point: 128°C, tensile elongation: 800%, density: 0.9 g / cm³ ３ WSX03 corresponds to (A-3) propylene-α-olefin resin in the present invention. Polyolefin resin (A-4): Wintec WMG03 manufactured by Nippon Polypropylene Co., Ltd., melting point: 143°C, tensile elongation: 200%, density: 0.9 g / cm³ ３ WMG03 does not fall under any of the components (A-1) to (A-3) in this disclosure.

[0091] (B) Acid-modified polyolefin resin Acid-modified polyolefin resin (B-1): PMA H1100P manufactured by Toyobo Co., Ltd., maleic anhydride graft-modified polypropylene resin, melting point: 147°C, molecular weight Mw: 74000

[0092] (C) Styrene-based block copolymer Styrene-based block copolymer (C-1): SIBSTAR 102T manufactured by Kaneka Corporation, styrene-isobutylene-styrene block copolymer, styrene content: 15% by mass, MFR: 0.6 g / 10 min (230°C, 2.16 kg), density: 0.94 g / cm³ ３ Styrene-based block copolymer (C-2): ToughTec H1043 manufactured by Asahi Kasei Corporation, styrene-ethylene-butylene-styrene block copolymer, styrene content: 67% by mass, MFR: 2.0 g / 10 min (230°C, 2.16 kg), density: 0.97 g / cm³ ３

[0093] (D) Adhesion Improvers Adhesion improver (D-1): YS Polystar T160 manufactured by Yasuhara Chemical Co., Ltd., terpene-modified phenol resin, hydroxyl value: 60 mg KOH / g Adhesion improver (D-2): YS Polystar G150 manufactured by Yasuhara Chemical Co., Ltd., terpene-modified phenol resin, hydroxyl value: 140 mg KOH / g

[0094] (E) Filler (E-1): K-1 manufactured by Nippon Talc Co., Ltd., talc, plate-like, particle size (D50): 8.0 μm, aspect ratio: 3-10 Filler (E-2): I.38P manufactured by Volclay Japan Co., Ltd., montmorillonite, plate-like, size: 14-18 μm, aspect ratio: 100-500

[0095] After dry-blending each of the above components in predetermined proportions, the mixture was supplied to a twin-screw extruder and melt-kneaded at a die temperature of 160°C to 220°C to obtain resin compositions 1 to 33. For each of the obtained resin compositions, the melt viscosity, water vapor barrier properties, T-peel adhesion strength, and thermal shock resistance were evaluated according to the method described above. The formulations and evaluation results for each resin composition are shown in Tables 1 and 2.

[0096]

[0097]

[0098] As shown in Table 1, the resin compositions of Examples 1 to 16, which satisfy the requirements of this disclosure, showed well-balanced and excellent results in all evaluation items: melt viscosity (fluidity), water vapor permeability (water vapor barrier properties), T-peel adhesive strength (adhesion), and thermal shock resistance. On the other hand, as shown in Table 2, Comparative Examples 1 to 17 were inferior in one or more properties for the following reasons. Comparative Example 1 did not contain propylene-α-olefin copolymer (A-3), resulting in low mechanical properties at high temperatures and poor adhesive strength at high temperatures (120°C). Comparative Examples 2 and 3 did not contain propylene-α-olefin copolymer (A-2), resulting in low flexibility and poor adhesive strength at room temperature (25°C). This tendency was particularly pronounced in Comparative Example 3. Comparative Example 4 did not contain polyolefin resin (A-1), resulting in low crystallinity, poor water vapor barrier properties, and poor adhesive strength at high temperatures (120°C). Comparative Examples 5 to 10 had difficulty achieving both adhesive strength at room temperature (25°C), adhesive strength at high temperature (120°C), and water vapor barrier properties because the blending ratio (a1, a2, a3) of component (A) polyolefin resin was outside the specified range. Comparative Example 11 did not contain styrene-isobutylene-styrene block copolymer (C-1), resulting in poor thermal shock resistance. Comparative Example 12 had a high content of styrene-isobutylene-styrene block copolymer (C-1), which reduced mechanical properties at high temperatures and resulted in poor adhesive strength at high temperature (120°C). Comparative Example 13 had an insufficient content of (D) adhesion promoter, resulting in a significant increase in melt viscosity. Comparative Example 14 had an excessive content of (D) adhesion promoter, which reduced the cohesive force of the resin composition and resulted in poor adhesive strength at room temperature (25°C). Comparative Example 15 did not contain (E) filler, resulting in poor water vapor barrier properties. Comparative Example 16 had poor adhesive strength at high temperatures (120°C) because it contained an excessive amount of (E) filler. Comparative Example 17 had poor water vapor barrier properties because it used styrene-ethylene-butylene-styrene block copolymer (C-2) instead of styrene-isobutylene-styrene block copolymer (C-1).

[0099] The resin composition of this disclosure has a low melt viscosity (excellent fluidity) suitable for low-pressure molding. Furthermore, it possesses high adhesion to substrates such as aluminum, excellent water vapor barrier properties, and impact resistance under severe temperature cycling. Due to these excellent properties, the resin composition of the present invention is extremely useful as a sealing material for electrical and electronic components requiring high levels of waterproofing and moisture resistance, and as a hot-melt adhesive for joining various components.

[0100] O1: A straight line passing through coordinates (30, 43, 27) and (43, 30, 27) P1: A straight line passing through coordinates (43, 30, 27) and (43, 17, 40) Q1: A straight line passing through coordinates (43, 17, 40) and (18.5, 18.5, 63) R1: A straight line passing through coordinates (18.5, 18.5, 63) and (17, 43, 40) S1: A straight line passing through coordinates (17, 43, 40) and (30, 43, 27) ●: Plot of each example ■: Plot of each comparative example (The composition of component (A) in Comparative Examples 11 to 17 is the same as in Example 1 and is therefore omitted) Numbers in the triangular chart: Number of each example or comparative example

Claims

1. A resin composition comprising a polyolefin resin (A), an acid-modified polyolefin resin (B), a styrene-isobutylene-styrene block copolymer (C), an adhesion promoter (D), and a filler (E), wherein the polyolefin resin (A) contains: (A-1) a polypropylene resin, (A-2) a propylene-α-olefin copolymer having a tensile elongation of 1000% or more, and (A-3) a propylene-α-olefin copolymer having a tensile elongation of 300% or more and less than 1000%, and when the total amount of (A-1), (A-2), and (A-3) is 100% by mass, the content of (A-1) is [a1]% by mass, the content of (A-2) is [a2]% by mass, and the content of (A-3) is [a3]% by mass, A resin composition in which, in a coordinate system (A-1 content, A-2 content, A-3 content) where the contents of (A-1), (A-2), and (A-3) are the sides of a triangular diagram, a1, a2, and a3 lie within a region (including points on the boundary lines) enclosed by the following five lines: line O1, line P1, line Q1, line R1, and line S1. Line O1: A line passing through the point (30 mass%, 43 mass%, 27 mass%) and the point (43 mass%, 30 mass%, 27 mass%). Line P1: A line passing through the point (43 mass%, 30 mass%, 27 mass%) and the point (43 mass%, 17 mass%, 40 mass%). Line Q1: A line passing through the point (43 mass%, 17 mass%, 40 mass%) and the point (18.5 mass%, 18.5 mass%, 63 mass%). Straight line R1: A straight line passing through the points (18.5 mass%, 18.5 mass%, 63 mass%) and (17 mass%, 43 mass%, 40 mass%). Straight line S1: A straight line passing through the points (17 mass%, 43 mass%, 40 mass%) and (30 mass%, 43 mass%, 27 mass%). The content in the above straight lines is expressed in the order of (A-1 content, A-2 content, A-3 content).

2. The resin composition according to claim 1, wherein in a total of 100 parts by mass of the polyolefin resin (A), the acid-modified polyolefin resin (B), the styrene-isobutylene-styrene block copolymer (C), and the adhesion promoter (D), the styrene-isobutylene-styrene block copolymer (C) is 8 to 27 parts by mass, the adhesion promoter (D) is 8 to 27 parts by mass, and the filler (E) is 1 to 13 parts by mass with respect to the total of 100 parts by mass, and the filler (E) is in the form of a plate.

3. The resin composition according to claim 1, wherein the melting point of the acid-modified polyolefin resin (B) is 100°C or higher.

4. The resin composition according to claim 1, wherein the styrene content in 100% by mass of the styrene-isobutylene-styrene block copolymer (C) is 10 to 30% by mass.

5. The resin composition according to claim 1, wherein the hydroxyl value of the adhesion agent (D) is 1 to 100 mg KOH / g.

6. The resin composition according to claim 1, wherein, in a total of 100 parts by mass of the polyolefin resin (A), the acid-modified polyolefin resin (B), the styrene-isobutylene-styrene block copolymer (C), and the adhesion promoter (D), the content of the polyolefin resin (A) is 38 to 70 parts by mass, and the content of the acid-modified polyolefin resin (B) is 1 to 17 parts by mass.

7. The resin composition according to claim 1, wherein the (A-1) polypropylene resin is a propylene homopolymer, the (A-2) is at least one selected from the group consisting of propylene-butene copolymer, propylene-heptene copolymer, propylene-hexene copolymer, propylene-octene copolymer, and propylene-ethylene-butene copolymer, and the (A-3) is at least one selected from the group consisting of propylene-ethylene copolymer, propylene-butene copolymer, propylene-heptene copolymer, propylene-hexene copolymer, propylene-octene copolymer, and propylene-ethylene-butene copolymer.

8. The resin composition according to claim 1, wherein the melt flow rates of (A-1), (A-2), and (A-3) are each 2 to 60 g / 10 min.

9. The resin composition according to claim 1, wherein the acid-modified polyolefin resin (B) is at least one selected from the group consisting of ethylene-vinyl acetate-maleic anhydride terpolymer, ethylene-ethyl acrylate-maleic anhydride terpolymer, maleic anhydride graft-modified polypropylene, and maleic anhydride graft-modified propylene-α-olefin copolymer.

10. The resin composition according to claim 1, wherein the adhesion agent (D) is at least one selected from the group consisting of phenol compounds, xylene-modified phenol resins, terpene-modified phenol resins, and hydrogenated terpene-modified phenol resins.

11. The resin composition according to claim 1, wherein the filler (E) is at least one selected from the group consisting of glass beads, calcium carbonate, kaolin, talc, clay, glass fibers, and carbon fibers.

12. A hot melt adhesive composition containing the resin composition according to any one of claims 1 to 11.

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