CN118043416A - Curable adhesive sheet - Google Patents

Curable adhesive sheet Download PDF

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Publication number
CN118043416A
CN118043416A CN202280063976.6A CN202280063976A CN118043416A CN 118043416 A CN118043416 A CN 118043416A CN 202280063976 A CN202280063976 A CN 202280063976A CN 118043416 A CN118043416 A CN 118043416A
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CN
China
Prior art keywords
curable adhesive
mass
less
release film
group
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Pending
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CN202280063976.6A
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Chinese (zh)
Inventor
西嶋健太
樫尾干广
泉直史
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Lintec Corp
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Lintec Corp
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Publication of CN118043416A publication Critical patent/CN118043416A/en
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
    • C09J11/08—Macromolecular additives
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J201/00—Adhesives based on unspecified macromolecular compounds
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
    • C09J7/35—Heat-activated
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/40—Adhesives in the form of films or foils characterised by release liners

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Laminated Bodies (AREA)
  • Adhesive Tapes (AREA)
  • Adhesives Or Adhesive Processes (AREA)

Abstract

The present invention provides a curable adhesive sheet, comprising: a curable adhesive layer capable of forming a cured product having a dielectric loss tangent of 0.01 or less at 23 ℃ and 1 GHz; and a1 st release film and a2 nd release film sandwiching both sides of the curable adhesive layer, wherein the 1 st release film and the 2 nd release film have: and a release layer formed from a non-silicone release agent on one surface of the resin film and in contact with the surface of the curable adhesive layer, the curable adhesive sheet satisfying the following element (I). Element (I): the peel force (R1) when the 1 st release film is peeled from the curable adhesive layer at a peel angle of 180 DEG and a peel speed of 300 mm/min is 250mN/50mm or less.

Description

Curable adhesive sheet
Technical Field
The present invention relates to a curable adhesive sheet.
Background
In recent years, with miniaturization and weight reduction of electronic devices, flexible printed wiring boards (FPCs) are being used as wiring members. The FPC may be manufactured by, for example, etching a copper foil of a copper-clad laminate in which a copper foil is bonded to an insulating resin film such as polyimide to form a circuit.
In addition, the following operations are performed for such FPC: a cover film (coverlay) sheet having an insulating resin base material and an adhesive layer is bonded to a copper foil on which a circuit is formed to protect the circuit.
As an example of such a cover film, patent document 1 discloses an invention relating to a thermosetting adhesive sheet in which a thermosetting adhesive layer composed of an adhesive composition containing a predetermined amount of a styrene-based elastomer, a modified polyphenylene ether resin having a polymerizable group at the terminal, an epoxy resin, and an epoxy resin curing agent is formed on a substrate.
Prior art literature
Patent literature
Patent document 1: japanese patent application laid-open No. 2019-135280.
Disclosure of Invention
Problems to be solved by the invention
However, in the FPC, from the viewpoint of suppressing defects such as defective operation of the electronic device, the contamination of foreign substances or the transfer of contamination components becomes a problem. For example, in the thermosetting adhesive sheet described in patent document 1, in order to protect the surface of the thermosetting adhesive layer, there is a case where a silicone release sheet having a layer made of a silicone release agent is laminated on the thermosetting adhesive layer. Silicone release sheets are widely used because they are easily released from a thermosetting adhesive layer during use and have excellent handleability.
However, the silicone-based release sheet has the following problems: with the lapse of time, the silicon (Si) component of the layer composed of the silicone-based release agent is transferred to the curable adhesive layer, and the silicon component in the curable adhesive layer is transferred to the surface of the FPC as the adherend, which is likely to be a cause of defective operation of the electronic device or the like.
Therefore, a curable adhesive sheet excellent in handling properties while suppressing contamination of an adherend is demanded.
Means for solving the problems
The present invention provides a curable adhesive sheet, which comprises: a curable adhesive layer of a cured product having a dielectric loss tangent of a predetermined value or less, and a1 st release film and a 2 nd release film sandwiching both sides of the curable adhesive layer, wherein the 1 st release film and the 2 nd release film have a release layer formed of a non-silicone release agent and in contact with the surface of the curable adhesive layer on the resin film, and the release force at the time of releasing the 1 st release film from the curable adhesive layer is adjusted to a predetermined value or less.
Specifically, as one embodiment provided by the present invention, the following is described.
[1] A curable adhesive sheet comprising: a curable adhesive layer capable of forming a cured product having a dielectric loss tangent of 0.01 or less at 23 ℃ and 1 GHz; a1 st release film and a2 nd release film sandwiching both sides of the curable adhesive layer,
The 1 st release film and the 2 nd release film have: a resin film, and a release layer formed on one surface of the resin film by a non-silicone release agent and contacting with the surface of the curable adhesive layer,
The curable adhesive sheet satisfies the following element (I).
Element (I): the peel force (R1) when the 1 st release film is peeled from the curable adhesive layer at a peel angle of 180 DEG and a peel speed of 300 mm/min is 250mN/50mm or less.
[2] The curable adhesive sheet according to the item (1), which further satisfies the following element (II).
Element (II): the peel force (R1) is smaller than the peel force (R2) when the 2 nd release film is peeled from the curable adhesive layer at a peel angle of 180 DEG and a peel speed of 300 mm/min.
[3] The curable adhesive sheet according to the item [2], which further satisfies the following element (IIa).
Element (IIa): the ratio [ (R1)/(R2) ] of the peeling force (R1) to the peeling force (R2) is 0.97 or less.
[4] The curable adhesive sheet according to any one of the above [1] to [3], which further satisfies the following element (III).
Element (III): the peel force (R2) when the 2 nd release film is peeled from the curable adhesive layer at a peel angle of 180 DEG and a peel speed of 300 mm/min is 300mN/50mm or less.
[5] The curable adhesive sheet according to any one of the above [1] to [4], wherein the non-silicone release agent for forming at least one release layer of the 1 st release film and the 2 nd release film is an alkyd release agent.
[6] The curable adhesive sheet according to any one of the above [1] to [5], wherein the curable adhesive layer is a layer formed of a curable adhesive composition containing an adhesive resin (A).
[7] The curable adhesive sheet according to the item [6], wherein the curable adhesive composition further comprises a polyphenylene ether resin (B).
[8] The curable adhesive sheet according to any one of [1] to [7], wherein the resin film (1) constituting the 1 st release film is a colored resin film.
[9] The curable adhesive sheet according to any one of [1] to [8], wherein the resin film (2) constituting the 2 nd release film and the resin film (1) constituting the 1 st release film are visually distinguishable.
Effects of the invention
The curable adhesive sheet according to one preferred embodiment of the present invention is capable of suppressing contamination of an adherend, and is capable of easily removing a release film when used, and is excellent in handleability, and is suitable for use as a cover sheet, for example.
Drawings
FIG. 1 is a schematic cross-sectional view of an example of the structure of a curable adhesive sheet according to the present invention in the thickness direction of the adhesive sheet.
Detailed Description
The numerical ranges recited herein can be arbitrarily combined with upper and lower limits. For example, when the numerical range is described as "preferably 20 to 120, more preferably 40 to 90", the numerical range of "20 to 90" or the numerical range of "40 to 120" is also included in the numerical range described in the present specification. For example, when the numerical range is "preferably 20 or more, more preferably 40 or more, and further preferably 120 or less, more preferably 90 or less," the range of "20 to 90" or the range of "40 to 120" is included in the numerical range described in the present specification.
The numerical ranges described in the present specification are, for example, "60 to 100" and "60 or more and 100 or less".
In the specification of the upper limit and the lower limit described in the present specification, the numerical ranges from the lower limit to the upper limit may be arbitrarily selected from the respective options, and may be arbitrarily combined.
In addition, as a preferred embodiment described in the present specification, a plurality of the various elements described may be combined.
In the present specification, for example, "(meth) acrylate" is used as a term indicating both "acrylate" and "methacrylate", and the same applies to other similar terms.
In the present specification, the "active ingredient" of the curable adhesive composition refers to a component from which a diluting solvent of water or an organic solvent is removed from the components contained in the curable adhesive composition.
In the present specification, the number average molecular weight (Mn) is a value in terms of standard polystyrene measured by Gel Permeation Chromatography (GPC), specifically, a value measured according to the method described in examples.
In the present specification, the thickness of each layer constituting the curable adhesive sheet is a value measured in accordance with JIS K7130 (1999), and can be measured, for example, by using a constant pressure thickness measuring instrument (manufactured by the company TECLOCK, product name "PG-02J").
[ Composition of curable adhesive sheet ]
Fig. 1 is a schematic cross-sectional view of an example of the structure of the curable adhesive sheet of the present invention in the thickness direction.
As shown in fig. 1, the curable adhesive sheet 1 of the present invention includes: a curable adhesive layer 10, and a1 st release film 21 and a2 nd release film 22 which sandwich both sides of the curable adhesive layer 10.
The curable adhesive layer 10 can be cured to form a cured product having a dielectric loss tangent of 0.01 or less at 23 ℃ and 1 GHz.
The 1 st release film 21 further includes: a resin film 212, and a release layer 211 on one surface of the resin film 212 and in contact with the surface 10a of the curable adhesive layer 10.
Similarly, the 2 nd release film 22 also has: a resin film 222, and a release layer 221 on one surface of the resin film 222 and in contact with the surface 10b of the curable adhesive layer 10.
The release layers 211 and 221 of the 1 st release film 21 and the 2 nd release film 22 are layers made of a non-silicone release agent.
Since the release layers 211 and 221 are layers made of a non-silicone release agent, the silicon (Si) component is not transferred to the surfaces 10a and 10b of the curable adhesive layer 10 that are in contact with them. Therefore, the curable adhesive sheet of the present invention can suppress contamination due to transfer of the silicon component to the adherend.
However, the curable adhesive sheet of the present invention has a low dielectric loss tangent of 0.01 or less in the curable adhesive layer.
In general, the curable adhesive layer having a low dielectric loss tangent is often composed of a component having no polar group or a component having a low polarity, and the surface polarity of the curable adhesive layer tends to be low. In the case of using the silicone release film, when the release film is laminated on the surface of the curable adhesive layer having a low polarity and then removed, the releasability from the surface of the curable adhesive layer does not become a problem.
However, when a release film having a release layer formed of a non-silicone release agent is used and laminated on the surface of a curable adhesive layer having low polarity, there is a problem in that the release film is not sufficiently releasable and is difficult to release when the release film is removed from the surface of the curable adhesive layer.
In the curable adhesive sheet of the present invention, the problem of difficulty in peeling the release film from the surface of the curable adhesive layer can be solved by adjusting the following element (I). Element (I): the peel force (R1) when the 1 st release film is peeled from the curable adhesive layer at a peel angle of 180 DEG and a peel speed of 300 mm/min is 250mN/50mm or less.
By satisfying the above-described element (I), the 1 st release film can be easily peeled from the surface of the curable adhesive layer at the time of use, and a curable adhesive sheet excellent in handleability can be produced.
In the curable adhesive sheet according to an embodiment of the present invention, the peel force (R1) specified in the element (I) is 250mN/50mm or less, preferably 200mN/50mm or less, more preferably 150mN/50mm or less, still more preferably 110mN/50mm or less, still more preferably 90mN/50mm or less, and further preferably 5mN/50mm or more, more preferably 10mN/50mm or more, still more preferably 20mN/50mm or more from the above point of view.
The method for adjusting the release force (R1) to the above range can be adjusted by appropriately setting the types of the resin film constituting the 1 st release film and the release agent forming the release agent layer, and the types and contents of the components contained in the curable adhesive composition forming the curable adhesive layer. The specific adjustment method is described in detail below in the description of each configuration.
The curable adhesive sheet according to one embodiment of the present invention preferably satisfies the following element (II) in addition to the above element (I).
Element (II): the peel force (R1) is smaller than the peel force (R2) when the 2 nd release film is peeled from the curable adhesive layer at a peel angle of 180 DEG and a peel speed of 300 mm/min.
By satisfying the above (II), the 1 st release film can be peeled off from the surface of the curable adhesive layer more easily, and a curable adhesive sheet having more excellent handleability can be produced.
From the above point of view, the curable adhesive sheet according to one embodiment of the present invention preferably satisfies the following element (IIa) in addition to the above element (I).
Element (IIa): the ratio [ (R1)/(R2) ] of the peeling force (R1) to the peeling force (R2) is 0.97 or less.
The ratio [ (R1)/(R2) ] of the peeling force (R1) to the peeling force (R2) specified in the above element (IIa) is 0.97 or less, preferably 0.95 or less, more preferably 0.88 or less, still more preferably 0.80 or less, from the viewpoint that the 1 st release film can be peeled from the surface of the curable adhesive layer more easily and the curable adhesive sheet is produced more excellent in handleability. The lower limit of the ratio [ (R1)/(R2) ] of the peeling force (R1) to the peeling force (R2) defined in the above element (IIa) is not particularly limited, but is preferably 0.2 or more, and more preferably 0.35 or more.
The curable adhesive sheet according to one embodiment of the present invention preferably satisfies the following element (III) in addition to the above element (I), more preferably satisfies the following element (III) in addition to the above elements (I) and (II), and even more preferably satisfies the following element (III) in addition to the above elements (I) and (IIa).
Element (III): the peel force (R2) was 300mN/50mm or less.
By satisfying the above-described element (III), the 2 nd release film can be easily peeled off even after the curable adhesive layer exposed by removing the 1 st release film is adhered to the adherend, and a curable adhesive sheet excellent in handleability can be produced.
In the curable adhesive sheet according to an embodiment of the present invention, the peel force (R1) specified in the element (I) is 300mN/50mm or less, preferably 250mN/50mm or less, more preferably 220mN/50mm or less, still more preferably 150mN/50mm or less, still more preferably 110mN/50mm or less, and further preferably 20mN/50mm or more, more preferably 30mN/50mm or more, still more preferably 40mN/50mm or more from the above point of view.
The release force (R2) may be adjusted by appropriately setting the types of the resin film constituting the release film 2 and the release agent forming the release agent layer, and the types and contents of the components contained in the curable adhesive composition forming the curable adhesive layer. The specific adjustment method is described in detail below in the description of each configuration.
In the present specification, the peel forces (R1) and (R2) are values measured by the method described in examples described below.
Hereinafter, each layer of the curable adhesive sheet and the material for forming the layer constituting one embodiment of the present invention will be described.
[1 St Release film, 2 nd Release film ]
The 1 st release film and the 2 nd release film of the curable adhesive sheet according to one embodiment of the present invention may be any films having a resin film and a release layer formed of a non-silicone release agent.
Examples of the resin component contained in the resin film include: and polyester resins such as polyethylene terephthalate resin, polybutylene terephthalate resin and polyethylene naphthalate resin, polyolefin resins such as polypropylene resin and polyethylene resin, polycarbonate resins, and mixed resins obtained by using 2 or more of these resins in combination.
The resin film may contain additives such as ultraviolet absorbers, antistatic agents, light stabilizers, antioxidants, resin stabilizers, fillers, colorants (pigments, dyes, etc.) in addition to the resin component.
The resin film may be a colored resin film.
The colored resin film may be a foamed resin film obtained by foaming a resin layer for coloring. The foamed resin film is generally a white and opaque colored resin film. In addition, a resin film formed from a resin composition containing both a resin component and a filler also has reduced transparency due to scattering of light, and becomes a colored resin film.
Further, in order to be colored in a desired color, a colored resin film formed from a resin composition containing both a resin component and a desired colorant can be formed.
In the curable adhesive sheet according to one embodiment of the present invention, the resin film (1) constituting the 1 st release film is preferably a colored resin film from the viewpoint of being a curable adhesive sheet having more excellent handleability.
The 1 st release film made of a colored resin film clearly distinguished from the 2 nd release film. For example, the use of the 1 st release film and the 2 nd release film can be prevented from being misused when the adhesive sheet is used, and the adhesive sheet can be used as a curable adhesive sheet with more excellent handleability. The colored resin film also includes a white resin film.
From the same point of view as described above, it is preferable that the resin film (2) constituting the 2 nd release film is visually distinguishable from the resin film (1) constituting the 1 st release film.
As a method that can be distinguished by visual observation, the following methods can be used: when the resin film (1) is made into a colored resin film, the resin film (2) is made into a colorless transparent resin film; alternatively, the resin film (2) may be a transparent or opaque colored resin film having a different color from the resin film (1), and examples thereof include: a method of attaching a visually recognizable mark to the surface of the resin film (2), and the like.
Among these, from the viewpoint of easily recognizing the surface state of the adherend via the 2 nd release film after peeling the 1 st release film and attaching the curable adhesive sheet to the adherend, or easily observing by other optical methods, a method that can be distinguished by visual observation is preferable: when the resin film (1) is formed into a colored resin film, a method of forming the resin film (2) into a colorless transparent resin film or a method of forming a transparent or opaque colored resin film having a different color from the resin film (1) is more preferable, and a method of forming the resin film (2) into a colorless transparent resin film is more preferable.
Examples of the non-silicone release agent that is a material for forming the release layer include: an olefinic stripper, an isoprene stripper, a rubber-based elastomer stripper such as a butadiene stripper, a long-chain alkyl stripper, an alkyd stripper, a fluorine stripper, and the like.
Among these, from the viewpoint of adjusting the release forces (R1) and (R2) to satisfy the above-described elements (I) to (III), the above-described non-silicone release agent for forming at least one release layer of the 1 st release film and the 2 nd release film is preferably an alkyd release agent, and more preferably the above-described non-silicone release agent for forming the release layers of both the 1 st release film and the 2 nd release film is an alkyd release agent.
In the curable adhesive sheet according to one embodiment of the present invention, the thickness (T1) of the 1 st release film is preferably 10 μm or more, more preferably 20 μm or more, still more preferably 30 μm or more, and further preferably 200 μm or less, more preferably 100 μm or less, still more preferably 70 μm or less, still more preferably 45 μm or less, from the viewpoint of adjusting the release force (R1) to a range satisfying the above-mentioned element (I).
In the curable adhesive sheet according to one embodiment of the present invention, the thickness (T2) of the 2 nd release film is preferably 30 μm or more, more preferably 35 μm or more, and further preferably 270 μm or less, more preferably 210 μm or less, still more preferably 140 μm or less, from the viewpoint of adjusting the release force (R2) to a range satisfying the above-mentioned element (III).
From the viewpoint of producing a curable adhesive sheet that further satisfies the above elements (II) and (IIa), the thickness (T2) of the 2 nd release film is preferably 47 μm or more, more preferably 55 μm or more, and still more preferably 65 μm or more.
In the curable adhesive sheet according to one embodiment of the present invention, the ratio [ (T1)/(T2) ] of the thickness (T1) of the 1 st release film to the thickness (T2) of the 2 nd release film is preferably 0.15 or more, more preferably 0.20 or more, further preferably 0.25 or more, and further preferably 1.00 or less, more preferably 0.90 or less, further preferably 0.80 or less, from the viewpoint of preparing the curable adhesive sheet satisfying the above elements (II) and (IIa).
[ Curable adhesive layer ]
The curable adhesive layer of the curable adhesive sheet according to one embodiment of the present invention can form a cured product having a dielectric loss tangent of 0.01 or less at 23 ℃ and 1 GHz.
The dielectric loss tangent of the cured product at 23 ℃ and 1GHz is 0.01 or less, preferably 0.005 or less, and more preferably 0.002 or less.
The lower limit of the dielectric loss tangent of the cured product at 23℃and 1GHz is not particularly limited, but is preferably 0.00005 or more, more preferably 0.0001 or more.
In the present specification, the dielectric loss tangent of the cured product refers to a value measured by a method described in examples described below.
The method of curing the curable adhesive layer may be a thermosetting method or a photo-curing method, and may be appropriately selected depending on the application. For example, if the curable adhesive sheet according to one embodiment of the present invention is used as a cover film to form a cured product for protecting a circuit board, the thermosetting method is preferable.
In the curable adhesive sheet according to one embodiment of the present invention, the thickness of the curable adhesive layer is preferably 3.0 μm or more, more preferably 5.0 μm or more, still more preferably 10 μm or more, still more preferably 15 μm or more, and still more preferably 60 μm or less, more preferably 45 μm or less, from the viewpoint of forming a cured product having a thickness to such an extent that the circuit board can be protected.
The curable adhesive layer of the curable adhesive sheet according to one embodiment of the present invention may be formed of a curable adhesive composition containing the adhesive resin (a) (hereinafter, also referred to as "component (a)").
The curable adhesive composition used in one embodiment of the present invention preferably further contains a polyphenylene ether resin (B) (hereinafter also referred to as "component (B)") and more preferably contains a polyfunctional compound (C) (hereinafter also referred to as "component (C)") in addition to the components (a) and (B), and the component (C) has 2 or more unsaturated hydrocarbon groups having a double bond at the terminal end, from the viewpoint of producing a curable adhesive sheet adjusted so as to satisfy the above-described component (I) or (III) and from the viewpoint of producing a composition capable of forming a cured product having improved adhesive strength and low dielectric characteristics.
The curable adhesive composition used in one embodiment of the present invention preferably further contains 1 or more selected from the group consisting of a cationic polymerization initiator (D) (hereinafter, also referred to as "component (D)"), a crosslinking agent (E) (hereinafter, also referred to as "component (E)") which is reactive with the above-described reactive functional group of component (a), and a silane coupling agent (F) (hereinafter, also referred to as "component (F)").
The curable adhesive composition used in one embodiment of the present invention may contain additives other than these components (a) to (F) within a range that does not impair the effects of the present invention.
In the curable adhesive composition used in one embodiment of the present invention, from the viewpoint of producing a curable adhesive sheet adjusted so as to satisfy the above-described element (I) or (III) and from the viewpoint of producing a curable adhesive layer or a cured product thereof capable of forming an improved adhesive strength and low dielectric characteristics, the total content of the component (a) and the component (B) is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, still more preferably 75% by mass or more, and further preferably 100% by mass or less, more preferably 99.90% by mass or less, still more preferably 99.00% by mass or less, still more preferably 95.00% by mass or less, relative to the total amount (100% by mass) of the active components of the curable adhesive composition.
From the above point of view, in the curable adhesive composition used in one embodiment of the present invention, the total content of the component (a), the component (B), the component (C) and the component (D) is preferably 60% by mass or more, more preferably 75% by mass or more, still more preferably 90% by mass or more, and in addition, is usually 100% by mass or less, 99.70% by mass or less, or 90% by mass or less, relative to the total amount (100% by mass) of the active ingredients of the curable adhesive composition.
From the above point of view, in the curable adhesive composition used in one embodiment of the present invention, the total content of the component (a), the component (B), the component (C), the component (D), the component (E) and the component (F) is preferably 60% by mass or more, more preferably 75% by mass or more, still more preferably 90% by mass or more, and in addition, is usually 100% by mass or less, 99.70% by mass or less, or 90% by mass or less, relative to the total amount (100% by mass) of the active ingredients of the curable adhesive composition.
Details of the components contained in the curable adhesive composition used in one embodiment of the present invention will be described below.
< Component (A): adhesive resin >, adhesive resin
The curable adhesive composition used in one embodiment of the present invention preferably contains the adhesive resin (a). The composition containing the binder resin (a) can form a curable adhesive layer having excellent adhesive strength and good shape stability when a cured product is produced.
The binder resin (A) may be used alone or in combination of 2 or more.
In the curable adhesive composition used in one embodiment of the present invention, the content of the component (a) is preferably 35% by mass or more, more preferably 45% by mass or more, further preferably 55% by mass or more, and further preferably 90% by mass or less, more preferably 80% by mass or less, further preferably 75% by mass or less, relative to the total amount (100% by mass) of the active ingredients of the curable adhesive composition.
The number average molecular weight (Mn) of the binder resin (a) used in one embodiment of the present invention is preferably 10,000 or more, more preferably 25,000 or more, still more preferably 35,000 or more from the viewpoint of improving film forming property and forming a composition capable of forming a curable adhesive layer having good shape stability, and is preferably 150,000 or less, more preferably 100,000 or less, still more preferably 70,000 or less from the viewpoint of improving solubility of the component (a) with a diluting solvent and forming a composition having excellent coatability when the composition is brought into a solution state.
Examples of the binder resin (a) include: polyolefin-based resins, phenoxy-based resins, polyimide-based resins, polyamideimide-based resins, polyvinyl butyral-based resins, polycarbonate-based resins, styrene-based resins, and the like.
Among these, the binder resin (a) used in one embodiment of the present invention preferably contains a polyolefin resin from the viewpoint of being a composition that can form a cured product excellent in dielectric characteristics in a high frequency region (for example, 1GHz or more).
The polyolefin resin may be a polymer having a constituent unit derived from an olefin monomer, a polymer having a constituent unit derived from an olefin monomer alone, or a copolymer having a constituent unit derived from an olefin monomer and a constituent unit derived from a monomer copolymerizable with an olefin monomer.
Examples of the olefin monomer constituting the polyolefin resin include: the alpha-olefin having 2 or more carbon atoms is preferably an alpha-olefin having 2 to 8 carbon atoms, more preferably at least 1 selected from ethylene, propylene, 1-butene, isobutylene and 1-hexene, and still more preferably at least 1 selected from ethylene and propylene.
These olefin monomers may be used alone or in combination of 2 or more.
Examples of the monomer copolymerizable with the olefin monomer constituting the polyolefin resin include: vinyl acetate, (meth) acrylate, styrene, and the like. These monomers may be used alone or in combination of 2 or more.
Specifically, examples of the polyolefin-based resin used in one embodiment of the present invention include: ultra low density polyethylene (VLDPE), low Density Polyethylene (LDPE), medium Density Polyethylene (MDPE), high Density Polyethylene (HDPE), linear low density polyethylene, polypropylene (PP), ethylene-propylene copolymers, olefin-based elastomers (TPO), ethylene-vinyl acetate copolymers (EVA), ethylene- (meth) acrylic acid copolymers, ethylene- (meth) acrylate copolymers, and the like.
The binder resin (a) used in one embodiment of the present invention preferably contains a binder resin having a reactive functional group, more preferably contains 1 or more selected from a polyolefin resin having a reactive functional group and a styrene resin having a reactive functional group, and even more preferably contains at least a polyolefin resin (A1) having a reactive functional group, from the viewpoints of improving film forming properties, forming a composition capable of forming a curable adhesive layer having good shape stability, forming a composition capable of forming a cured product having improved low dielectric characteristics, and reducing peeling force when peeling the 1 st release film or the 2 nd release film from the curable adhesive layer.
In the curable adhesive composition used in one embodiment of the present invention, the content of the polyolefin resin (A1) is preferably 50 to 100 mass%, more preferably 70 to 100 mass%, and even more preferably 85 to 100 mass% with respect to the total amount (100 mass%) of the component (a) contained in the curable adhesive composition, from the viewpoint of a composition capable of forming a cured product having more excellent low dielectric characteristics.
Examples of the reactive functional group of the binder resin (a) include: carboxyl group, group having carboxylic anhydride structure, group having carboxylic ester structure, hydroxyl group, epoxy group, amide group, ammonium group, nitrile group, amino group, imide group, isocyanate group, acetyl group, thiol group, sulfo group, phosphine group, nitro group, halogen atom, alkoxysilyl group, and the like.
The reactive functional group of the binder resin (a) may be composed of 1 kind alone or 2 or more kinds in combination.
Among these, the reactive functional group of the binder resin (a) is preferably selected from a group consisting of a carboxyl group, a group having a carboxylic anhydride structure, an epoxy group, an amide group, an ammonium group, a nitrile group, an amino group, an imide group, an isocyanate group, an acetyl group, a thiol group, an ether group, a thioether group, a sulfo group, a phosphine group, a nitro group, a urethane group, a halogen atom and an alkoxysilyl group, and a group having a carboxylic anhydride structure is more preferably selected from a group consisting of a carboxyl group and a group having a carboxylic anhydride structure from the viewpoint of forming a composition capable of forming a cured product having more excellent adhesive strength and further more excellent low dielectric characteristics, and a group having a carboxylic anhydride structure is more preferably selected from the viewpoint of reducing the peeling force at the time of peeling the 1 st release film or the 2 nd release film from the curable adhesive layer.
The binder resin (a) used in one embodiment of the present invention may be a modified resin obtained by modifying a resin as a main chain with a modifier to introduce the above-described reactive functional group.
Specific examples of the modified resin include: the acid-modified resin having an acid group and the resin having a hydroxyl group are preferable from the viewpoint of forming a composition capable of forming a cured product having more excellent adhesive strength and from the viewpoint of reducing the peeling force when peeling the 1 st release film or the 2 nd release film from the curable adhesive layer, and the acid-modified resin having an acid group is more preferable from the viewpoint of forming a composition capable of forming a cured product having more excellent adhesive strength and further more excellent low dielectric characteristics.
The acid-modified resin or acid anhydride-modified resin (hereinafter also referred to as "unsaturated carboxylic acid or the like") is obtained, for example, by reacting an unsaturated carboxylic acid or the like with a resin as a main chain to introduce a carboxyl group or carboxylic acid anhydride structure for graft modification.
The method for introducing an unsaturated carboxylic acid or the like into the resin is not particularly limited, and examples thereof include: a method in which a resin, an unsaturated carboxylic acid, and the like are heated to a temperature equal to or higher than the melting point of the resin in the presence of a radical generator such as an organic peroxide or an azonitrile, and melted to react the resin and the unsaturated carboxylic acid; or a method in which a resin, an unsaturated carboxylic acid or the like is dissolved in an organic solvent, and then heated and stirred in the presence of a radical generator to react.
Examples of the unsaturated carboxylic acid include: maleic acid, fumaric acid, itaconic acid, citraconic acid, glutaconic acid (glutaconic acid), tetrahydrophthalic acid, aconitic acid, and the like.
Examples of the unsaturated carboxylic acid anhydride include: maleic anhydride, itaconic anhydride, glutaconic anhydride, citraconic anhydride, aconitic anhydride, norbornene dicarboxylic anhydride, tetrahydrophthalic anhydride, and the like.
These may be used alone or in combination of 2 or more.
Among these, maleic anhydride is preferable from the viewpoint of forming a composition that can form a cured product having more excellent adhesive strength and low dielectric characteristics.
From the viewpoint of forming a composition that can form a cured product having more excellent adhesive strength and low dielectric characteristics, the amount of unsaturated carboxylic acid or the like to be added to the resin is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 3 parts by mass, and even more preferably 0.2 to 1 part by mass, relative to 100 parts by mass of the resin.
< Component (B): polyphenylene ether resin
The curable adhesive composition used in one embodiment of the present invention preferably contains the polyphenylene ether resin (B) from the viewpoint of being a curable adhesive sheet adjusted so as to satisfy the above-described element (I) or (III) and from the viewpoint of being a composition capable of forming a cured product having improved adhesive strength and low dielectric characteristics.
The polyphenylene ether resin (B) may be used alone or in combination of 2 or more.
In the curable adhesive composition used in one embodiment of the present invention, the content of the component (B) is preferably 5 parts by mass or more, more preferably 12 parts by mass or more, still more preferably 17 parts by mass or more, and further preferably 80 parts by mass or less, more preferably 60 parts by mass or less, still more preferably 40 parts by mass or less, based on 100 parts by mass of the total amount of the component (a).
The number average molecular weight (Mn) of the polyphenylene ether resin (B) used in one embodiment of the present invention is preferably 1500 or more, more preferably 1700 or more, still more preferably 1900 or more from the viewpoint of the curable adhesive sheet adjusted so as to satisfy the above-described element (I) or (III) and the viewpoint of the composition capable of forming a cured product having improved adhesive strength and low dielectric characteristics, and from the viewpoint of the composition having good solubility with a diluent solvent and excellent coatability, the composition is preferably 7000 or less, more preferably 5500 or less, and still more preferably 4000 or less from the viewpoint of the composition being in the form of a solution.
The polyphenylene ether resin (B) used in one embodiment of the present invention may be any resin having a main chain having a constituent unit represented by at least one of the following general formulae (B-i) and (B-ii).
[ Chemical formula 1]
In the above general formula (b-i) or formula (b-ii), R a1 and R a2 are each independently a halogen atom (fluorine atom, chlorine atom, bromine atom or iodine atom), an alkyl group having 1 to 6 carbon atoms, or a phenyl group, preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, further preferably an alkyl group having 1 to 3 carbon atoms, further preferably a methyl group or an ethyl group, and particularly preferably a methyl group.
Examples of the alkyl group having 1 to 6 carbon atoms which may be selected as R a1 and R a2 include: methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, sec-butyl, isobutyl, n-pentyl, n-hexyl and the like.
M1 and m2 each independently represent an integer of 0 to 4, preferably an integer of 0 to 3, more preferably an integer of 0 to 2, and even more preferably 2.
The polyphenylene ether resin (B) used in one embodiment of the present invention is preferably a resin having a skeleton represented by the following formula (B-1) as a main chain, from the viewpoint of being a composition which is a cured product of a curable adhesive sheet adjusted so as to satisfy the above-mentioned element (I) or (III), and further has a low dielectric property and further has an improved adhesive strength.
[ Chemical formula 2]
In the above general formula (b-1), R a1 and R a2, and m1 and m2 are the same as defined in the above general formula (b-i) or formula (b-ii), and the kinds and numerical ranges for the suitable groups are also the same.
X is a divalent organic group, at least 1 hydrogen atom of which may be substituted with a substituent.
P1 and p2 are each independently an integer of 0 or more, and p1+p2 is an integer of 1or more.
* Represents the bonding position to the terminal group.
Examples of the divalent hydrocarbon group optionally used as X include: alkylene having 1 to 20 carbon atoms, oxyalkylene having 1 to 20 carbon atoms, alkenylene having 1 to 20 carbon atoms, cycloalkylene having 3 to 10 ring-forming carbon atoms, phenylene, biphenylene, naphthylene, a group formed by combining 2 or more of these groups, and the like.
The alkylene group, the oxyalkylene group, and the alkenylene group may be linear or branched.
The alkylene group, the oxyalkylene group and the alkenylene group may have a substituent selected from the group consisting of a halogen atom, a phenyl group, a biphenyl group, a naphthyl group and a cycloalkyl group having 3 to 10 carbon atoms.
The cycloalkylene group, the cycloalkenylene group, the phenylene group, the biphenylene group, and the naphthylene group may have a substituent selected from the group consisting of a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group (oxyalkyl) having 1 to 6 carbon atoms, and an alkenyl group having 1 to 6 carbon atoms.
Among these, X is preferably a group represented by the following formula (b-2) from the viewpoint of being a curable adhesive sheet adjusted so as to satisfy the above-described element (I) or (III) and being a composition capable of forming a cured product having further improved adhesive strength.
[ Chemical formula 3]
In the above general formula (b-2), R b1 and R b2 are each independently a halogen atom (fluorine atom, chlorine atom, bromine atom or iodine atom), an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms or an alkenyl group having 1 to 6 carbon atoms, preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, further preferably an alkyl group having 1 to 3 carbon atoms, further preferably a methyl group or an ethyl group, particularly preferably a methyl group.
Examples of the alkyl group having 1 to 6 carbon atoms which may be selected as R b1 and R b2 include: methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, sec-butyl, isobutyl, n-pentyl, n-hexyl and the like.
N1 and n2 are each independently an integer of 0 to 4, preferably an integer of 0 to 3, more preferably an integer of 1 to 3, and still more preferably 3.
In the above general formula (b-2), A is a single bond or a divalent hydrocarbon group.
Examples of the divalent hydrocarbon group which may be selected as A include: alkylene having 1 to 20 carbon atoms, oxyalkylene having 1 to 20 carbon atoms, alkenylene having 1 to 20 carbon atoms, cycloalkylene having 3 to 10 ring-forming carbon atoms, or cycloalkylene having 3 to 10 ring-forming carbon atoms.
The alkylene group, the oxyalkylene group, and the alkenylene group may be linear or branched.
Further, the hydrocarbon group optionally used as A may have a substituent selected from the group consisting of a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms and an alkenyl group having 1 to 6 carbon atoms.
Among these, from the viewpoint of forming a curable adhesive sheet adjusted so as to satisfy the above-described element (I) or (III) and forming a composition capable of forming a cured product having further improved adhesive strength, a is preferably a single bond or an alkylene group having 1 to 20 carbon atoms, more preferably a single bond.
The polyphenylene ether resin (B) used in one embodiment of the present invention is more preferably a resin having a skeleton represented by the following formula (B-3) as a main chain, from the viewpoint of being a curable adhesive sheet adjusted so as to satisfy the above-described element (I) or (III) and being a composition capable of forming a cured product having further improved adhesive strength.
[ Chemical formula 4]
In the above general formula (b-3), R a1 and R a2 are the same as defined in the above general formula (b-i) or formula (b-ii), and the kinds and numerical ranges for the suitable groups are also the same.
R b1 and R b2 are as defined in the above general formula (b-2), and the types and numerical ranges of the suitable groups are the same.
P1 and p2 are each independently an integer of 0 or more, and p1+p2 is an integer of 1or more.
* Represents the bonding position to the terminal group.
R a1、Ra2、Rb1 and R b2 in the general formula (b-3) are each independently preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, still more preferably an alkyl group having 1 to 3 carbon atoms, still more preferably a methyl group or an ethyl group, and particularly preferably a methyl group.
The polyphenylene ether resin (B) used in one embodiment of the present invention is preferably a polyphenylene ether resin having a vinyl group from the viewpoint of being a curable adhesive sheet adjusted so as to satisfy the above-mentioned element (I) or (III) and being a composition capable of forming a cured product having further improved low dielectric characteristics, crosslinkability and heat resistance.
The vinyl group contained in the polyphenylene ether resin (B) may be a group constituting a part of a hydrocarbon substituent such as a vinylbenzyl group and a vinylnaphthyl group. That is, the polyphenylene ether resin (B) is formed by bonding a vinyl group or a hydrocarbon group containing a vinyl group to a polyphenylene ether skeleton.
The polyphenylene ether resin (B) used in one embodiment of the present invention is preferably a resin having vinyl groups or vinyl-containing hydrocarbon groups at both ends of the main chain, from the viewpoint of being a curable adhesive sheet adjusted so as to satisfy the above-described element (I) or (III) and being a composition capable of forming a cured product excellent in low dielectric characteristics, crosslinkability and heat resistance.
The polyphenylene ether resin (B) having vinyl groups or vinyl-containing hydrocarbon groups at both terminals of the main chain can be obtained by introducing vinyl groups or vinyl-containing hydrocarbon groups to both terminals after forming a polyphenylene ether skeleton as the main chain.
Specifically, a 2-functional phenol compound is reacted with a monofunctional phenol compound to obtain a polymer having phenolic hydroxyl groups at both terminals, and then the terminal phenolic hydroxyl groups are subjected to vinylbenzyl etherification with 4- (chloromethyl) styrene, whereby a polyphenylene ether resin (B) having vinylbenzyl groups at both terminals of the polyphenylene ether skeleton can be obtained.
The polyphenylene ether resin (B) used in one embodiment of the present invention is preferably a compound represented by the following general formula (B-4).
[ Chemical formula 5]
P1 and p2 are each independently an integer of 0 or more, and p1+p2 is an integer of 1or more.
As the polyphenylene ether resin (B) used in one embodiment of the present invention, commercially available ones can be used. Examples of the commercial products include: OPE-2St (a compound represented by the above general formula (b-4)) manufactured by Mitsubishi gas chemical corporation, etc.
< Component (C): polyfunctional Compound
The curable adhesive composition used in one embodiment of the present invention preferably contains a polyfunctional compound (C) having 2 or more unsaturated hydrocarbon groups having a double bond at the terminal. The polyfunctional compound (C) in the present invention does not include compounds corresponding to the component (a) and the component (B).
By forming a composition containing both the polyphenylene ether resin (B) and the polyfunctional compound (C), a cured product having improved low dielectric characteristics and adhesive strength in a balanced manner can be formed. In particular, since the polyfunctional compound (C) has 2 or more unsaturated hydrocarbon groups, a crosslinked structure is formed in the obtained cured product, and a cured product having further improved adhesive strength can be formed.
The polyfunctional compound (C) may be used alone or in combination of 2 or more.
In the curable adhesive composition used in one embodiment of the present invention, the content of the component (C) is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, still more preferably 20 parts by mass or more, based on 100 parts by mass of the total amount of the component (a), from the viewpoint of forming a composition capable of forming a cured product excellent in low dielectric characteristics and also of improving adhesion, and the peel force (R1) and the peel force (R2) tend to increase when the content of the component (C) increases, so that the curable adhesive sheet is preferably 80 parts by mass or less, more preferably 60 parts by mass or less, still more preferably 40 parts by mass or less, from the viewpoint of adjusting the curable adhesive sheet so as to satisfy the above-described element (I) or (III).
In the curable adhesive composition used in one embodiment of the present invention, the content ratio [ (B)/(C) ] of the component (B) to the component (C) is preferably 15/85 or more, more preferably 30/70 or more, and further preferably 85/15 or less, more preferably 70/30 or less, from the viewpoint that a cured product having well-balanced low dielectric characteristics, adhesive strength and heat resistance can be formed.
In the curable adhesive composition used in one embodiment of the present invention, the total content of the component (B) and the component (C) is preferably 85 parts by mass or less, more preferably 75 parts by mass or less, further preferably 65 parts by mass or less, and further preferably 15 parts by mass or more, more preferably 25 parts by mass or more, further preferably 35 parts by mass or more, with respect to 100 parts by mass of the total amount of the component (a), from the viewpoint of being a curable adhesive sheet adjusted so as to satisfy the above-described component (I) or (III), and also from the viewpoint of being a curable adhesive sheet excellent in adhesion, and being a composition capable of forming a cured product excellent in adhesive strength.
The number of carbon atoms of each of the unsaturated hydrocarbon groups of the polyfunctional compound (C) used in one embodiment of the present invention is preferably 2 to 7, more preferably 2 to 4, and still more preferably 2 to 3.
Examples of the unsaturated hydrocarbon group include: vinyl, allyl, 3-butenyl, 4-pentenyl, 5-hexenyl, isopropenyl, 1-methyl-2-propenyl, vinylbenzyl, vinylnaphthyl, and the like.
Among these, the unsaturated hydrocarbon group of the polyfunctional compound (C) is preferably an allyl group.
The number of unsaturated hydrocarbons in the polyfunctional compound (C) used in one embodiment of the present invention is 2 or more, but is preferably 2 to 4, more preferably 2 to 3, and even more preferably 2 from the viewpoint of a composition which can form a cured product having a moderately dispersed cross-linked structure and suppress occurrence of cracks, and a composition which can suppress curing shrinkage in a bonding step of forming a cured product from a curable adhesive layer and can reduce warpage of a plate-like member such as a circuit board as an adherend.
From the viewpoint of forming a composition capable of forming a cured product having more uniformly improved low dielectric characteristics and adhesive strength, the polyfunctional compound (C) used in one embodiment of the present invention is preferably a polyfunctional compound having 2 or more unsaturated hydrocarbon groups as well as a saturated hydrocarbon group.
From the above point of view, the saturated hydrocarbon number of the polyfunctional compound (C) used in one embodiment of the present invention is preferably 1 to 4, more preferably 1 to 2, and still more preferably 1.
Examples of the saturated hydrocarbon group include: alkyl, alkyl substituted with alkoxy, and the like.
Examples of the alkyl group include: methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, sec-butyl, isobutyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, and the like.
The carbon number of the alkyl group is preferably 1 to 20, more preferably 4 to 18, still more preferably 6 to 16, still more preferably 8 to 15.
Examples of the alkyl group substituted with an alkoxy group include: methoxymethyl, ethoxymethyl, 2-methoxyethoxymethyl, benzyloxymethyl, and the like.
The number of carbon atoms of the alkoxy-substituted alkyl group is preferably 2 to 15, more preferably 2 to 12, and still more preferably 3 to 10.
The polyfunctional compound (C) used in one embodiment of the present invention preferably contains the polyfunctional compound (C1) having 2 unsaturated hydrocarbon groups described above.
As described above, the composition containing the polyfunctional compound (C1) having 2 unsaturated hydrocarbon groups can be a composition capable of forming a cured product in which occurrence of cracks is suppressed and warpage of a plate-like member such as a circuit board as an adherend is reduced, and can be a composition capable of forming a cured product in which low dielectric characteristics and adhesive strength are further improved.
From the above viewpoint, the polyfunctional compound (C1) is more preferably the polyfunctional compound having 2 unsaturated hydrocarbon groups and at least 1 saturated hydrocarbon group.
From the above point of view, in the curable adhesive composition used in one embodiment of the present invention, the content ratio of the polyfunctional compound (C1) is preferably 50 to 100% by mass, more preferably 70 to 100% by mass, still more preferably 80 to 100% by mass, and still more preferably 90 to 100% by mass, relative to the total amount (100% by mass) of the component (C) contained in the curable adhesive composition.
The polyfunctional compound (C) used in one embodiment of the present invention is preferably a polyfunctional compound having a heterocyclic skeleton. By containing the polyfunctional compound having a heterocyclic skeleton, a composition which can form a cured product having further improved low dielectric characteristics and adhesive strength can be obtained.
Specific examples of the heterocyclic skeleton include: isocyanurate or glycoluril backbones.
The polyfunctional compound (C) used in one embodiment of the present invention includes: a compound having an isocyanurate skeleton represented by the following general formula (c-1), and a compound having a glycoluril skeleton represented by the following general formula (c-2).
[ Chemical formula 6]
In the above general formula (c-1), R 11～R13 is an unsaturated hydrocarbon group having a double bond at the terminal, or a saturated hydrocarbon group, and at least 2 of R 11～R13 are the above unsaturated hydrocarbon groups.
In the general formula (c-2), R 21～R26 is a hydrogen atom, an unsaturated hydrocarbon group having a double bond at the terminal, or a saturated hydrocarbon group, and at least 2 of R 21～R26 are the unsaturated hydrocarbon groups.
Specific examples of the unsaturated hydrocarbon groups and saturated hydrocarbon groups which may be selected as R 11～R13 and R 21～R26 are as described above, and ranges of suitable carbon numbers are also as described above.
From the viewpoint of being able to form a composition capable of forming a cured product that suppresses the occurrence of cracks and reduces warpage of a plate-like member such as a circuit board as an adherend, and at the same time, being able to form a cured product that further improves low dielectric characteristics and adhesive strength, the polyfunctional compound (C) used in one embodiment of the present invention preferably contains a compound having an isocyanurate skeleton represented by the above general formula (C-1), and more preferably contains a compound (C11) having an isocyanurate skeleton represented by the following general formula (C-11).
[ Chemical formula 7]
In the above general formula (c-11), R a is a saturated hydrocarbon group, and specific examples are as described above.
Among these, R a is preferably an alkyl group. The carbon number of the alkyl group is preferably 1 to 20, more preferably 4 to 18, still more preferably 6 to 16, still more preferably 8 to 15.
From the above point of view, in the curable adhesive composition used in one embodiment of the present invention, the content of the compound (C11) is preferably 50 to 100% by mass, more preferably 70 to 100% by mass, still more preferably 80 to 100% by mass, and still more preferably 90 to 100% by mass, relative to the total amount (100% by mass) of the component (C) contained in the curable adhesive composition.
The polyfunctional compound (C) used in one embodiment of the present invention may be commercially available.
Specific commercial products include, for example: L-DAIC (product name, manufactured by Shimadzu chemical Co., ltd., compound represented by the above general formula (c-11)), TAIC (registered trademark) (product name, manufactured by Mitsubishi chemical Co., ltd., compound in which R 11～R13 in the above general formula (c-1) is an allyl group), TA-G (product name, manufactured by Shimadzu chemical Co., ltd., compound represented by the above general formula (c-2)), and the like.
The molecular weight (formula weight) of the polyfunctional compound (C) used in one embodiment of the present invention is preferably 200 or more, more preferably 230 or more, still more preferably 270 or more from the viewpoint of a composition that is easy to form a cured product having desired physical properties, and the peeling force (R1) and the peeling force (R2) tend to increase as the molecular weight of the component (C) decreases, so that the curable adhesive sheet is preferably 1000 or less, more preferably 800 or less, still more preferably 500 or less from the viewpoint of a composition that is easy to form a curable adhesive layer that is easy to adhere at normal temperature.
The boiling point of the polyfunctional compound (C) used in one embodiment of the present invention is preferably 175 to 350℃and more preferably 200 to 300 ℃.
The temperature for 5% weight reduction of the polyfunctional compound (C) used in one embodiment of the present invention is preferably 175 to 350℃and more preferably 200 to 300 ℃.
Further, the polyfunctional compound (C) used in one embodiment of the present invention is preferably a compound which is liquid (liquid) at 25 ℃ from the viewpoint of being a composition capable of forming a cured product excellent in low dielectric characteristics and also being a composition capable of easily forming a curable adhesive layer which is easily adhered at ordinary temperature.
In the present specification, the term "compound which is liquid at 25℃means a compound having fluidity at 25℃and specifically means a compound having a viscosity of 2 to 10000 mPas measured at 25℃and 1.0rpm using an E-type viscometer.
< Component (D): cationic polymerization initiator >, and
The curable adhesive composition used in one embodiment of the present invention preferably further contains a cationic polymerization initiator (D).
The polymerization reaction of the component (B) and the component (C) can be sufficiently performed by preparing a curable adhesive composition containing the cationic polymerization initiator (D), and the storage stability of the resulting curable adhesive layer can be improved.
The cationic polymerization initiator (D) may be used alone or in combination of 2 or more.
In the curable adhesive composition used in one embodiment of the present invention, the content of the component (D) is preferably 0.01 part by mass or more, more preferably 0.05 part by mass or more, still more preferably 0.10 part by mass or more, still more preferably 0.15 part by mass or more, still more preferably 0.20 part by mass or more, still more preferably 0.25 part by mass or more, particularly preferably 0.30 part by mass or more, and further preferably 6.0 parts by mass or less, more preferably 5.0 parts by mass or less, still more preferably 3.0 parts by mass or less, still more preferably 2.0 parts by mass or less, still more preferably 1.5 parts by mass or less, still more preferably 1.0 part by mass or less, particularly preferably 0.70 part by mass, from the viewpoint of forming a curable adhesive layer that can sufficiently proceed the polymerization reaction of the component (B) and the component (C) and that improves the storage stability.
The cationic polymerization initiator (D) used in one embodiment of the present invention may be a thermal cationic polymerization initiator or a photo cationic polymerization initiator, but is preferably a thermal cationic polymerization initiator from the viewpoint of enabling polymerization in a simple process.
The thermal cationic polymerization initiator used in one embodiment of the present invention is a compound that can generate a cationic species that initiates polymerization by heating, and examples thereof include: sulfonium salts, quaternary ammonium salts, phosphonium salts, diazonium salts, iodonium salts, and the like.
These thermal cationic polymerization initiators may be used alone or in combination of 2 or more.
Examples of the sulfonium salt include: triphenylsulfonium tetrafluoroborate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium hexafluoroarsonate, tris (4-methoxyphenyl) sulfonium hexafluoroarsonate, diphenyl (4-thiophenylphenyl) sulfonium hexafluoroarsonate, and the like.
Further, commercially available sulfonium salts can be used, and examples thereof include: adeka Opton SP-150, adeka Opton SP-170, adeka Opton CP-66, adeka Opton CP-77 (manufactured by ADEKA, inc. above); san-Aid SI-60L, san-Aid SI-80L, san-Aid SI-100L, san-Aid SI-B2A, san-Aid SI-B3 (manufactured by Sanxinshi chemical Co., ltd.); CYRACURE UVI-6974, CYRACURE UVI-6990 (manufactured by Union Carbide company, supra); UVI-508, UVI-509 (manufactured by GENERAL ELECTRIC, supra); FC-508, FC-509 (manufactured by Minnesota Mining & Manufacturing company, supra); CD-1010, CD-1011 (manufactured by Sartomer Corp., above); CI series products (manufactured by Nippon Caesada Co., ltd.).
Examples of the quaternary ammonium salt include: tetrabutylammonium tetrafluoroborate, tetrabutylammonium hexafluorophosphate, tetrabutylammonium bisulfate, tetraethylammonium tetrafluoroborate, tetraethylammonium p-toluenesulfonate, N-dimethyl-N-benzylanilinium hexafluoroantimonate, N-dimethyl-N-benzylanilinium tetrafluoroborate, N, N-dimethyl-N-benzylpyridinium hexafluoroantimonate, N-diethyl-N-benzyltriflate, N-dimethyl-N- (4-methoxybenzyl) pyridinium hexafluoroantimonate, N-diethyl-N- (4-methoxybenzyl) toluidinium hexafluoroantimonate, and the like.
Examples of phosphonium salts include: ethyl triphenyl phosphonium hexafluoroantimonate, tetrabutylphosphonium hexafluoroantimonate, and the like.
Examples of diazonium salts include: AMERICURE (manufactured by AMERICAN CAN), ULTRASET (manufactured by Adeka), and the like.
Examples of the iodonium salt include: diphenyliodonium hexafluoroarsenate, bis (4-chlorophenyl) iodonium hexafluoroarsenate, bis (4-bromophenyl) iodonium hexafluoroarsenate, phenyl (4-methoxyphenyl) iodonium hexafluoroarsenate, and the like.
Further, commercially available iodonium salts can be used, and examples thereof include: UV-9310C (manufactured by Toshiba silicone Co., ltd.) Photoinitiator 2074%Manufactured by Poulenc corporation), the UVE series of products (manufactured by GENERAL ELECTRIC corporation), the FC series of products (manufactured by Minnesota Mining & Manufacturing corporation), and the like.
In the case where the curable adhesive composition according to one embodiment of the present invention contains the cationic polymerization initiator (D), at least a part of the cationic polymerization initiator (D) may be a high-temperature reactive thermal cationic polymerization initiator having a peak top temperature of a heat generation peak obtained by differential scanning calorimetric measurement under the following conditions exceeding 120 ℃.
(Differential scanning calorimetric conditions)
A mixture of 0.1 part by mass of a cationic polymerization initiator to be measured, 100 parts by mass of bisphenol A diglycidyl ether, and 0.1 part by mass of gamma-butyrolactone was mixed as a measurement sample, and differential scanning calorimetric measurement was performed at a heating rate of 10 ℃/min from 30℃to 300℃to measure the peak temperature of a heat generation peak.
Examples of commercial products of the high-temperature reactive thermal cationic polymerization initiator include: san-Aid SI-B3, san-Aid SI-B4, san-Aid SI-B5, san-Aid SI-150 (all manufactured by Sanxinshi chemical Co., ltd.), and the like.
< Other reactive curing agent other than cationic polymerization initiator (D) >)
The curable adhesive composition used in one embodiment of the present invention may contain a reactive curing agent other than the cationic polymerization initiator (D) in place of or together with the cationic polymerization initiator (D) within a range that does not impair the effects of the present invention.
In the curable adhesive composition used in one embodiment of the present invention, the content of the other reactive curing agent may be set to 0 to 90 parts by mass, 0 to 50 parts by mass, 0 to 40 parts by mass, 0 to 30 parts by mass, 0 to 20 parts by mass, 0 to 10 parts by mass, 0 to 5.0 parts by mass, 0 to 2.0 parts by mass, 0 to 1.0 parts by mass, 0 to 0.10 parts by mass, 0 to 0.010 parts by mass, or 0 to 0.0010 parts by mass, based on 100 parts by mass of the total amount of the component (D).
On the other hand, in the case where the curable adhesive composition according to one embodiment of the present invention does not contain the cationic polymerization initiator (D), the content of the other reactive curing agent may be 0.01 part by mass or more, 0.05 part by mass or more, 0.10 part by mass or more, 0.15 part by mass or more, 0.20 part by mass or more, 0.25 part by mass or more, or 0.30 part by mass or more, or 6.0 parts by mass or less, 5.0 parts by mass or less, 3.0 parts by mass or less, 2.0 parts by mass or less, 1.5 parts by mass or less, 1.0 parts by mass or less, or 0.70 parts by mass or less, based on 100 parts by mass of the total amount of the component (B) and the component (C).
Examples of the reactive curing agent other than the cationic polymerization initiator (D) include: amine compounds such as benzyl methylamine and 2,4, 6-tris (dimethylaminomethyl) phenol; imidazole compounds such as 2-methylimidazole, 2-ethyl-4-methylimidazole and 2-heptadecylimidazole; lewis acids such as boron trifluoride/monoethylamine complex, boron trifluoride/piperazine complex, and the like; peroxides such as di (t-butylperoxy) diisopropylbenzene, and the like.
< Ingredient (E): crosslinking agent >
In the case where the curable adhesive composition used in one embodiment of the present invention contains a binder resin having a reactive functional group as the component (a), it is preferable to further contain a crosslinking agent (E) that can react with the reactive functional group.
The composition containing the component (A) and the crosslinking agent (E) can form a curable adhesive layer having a high effect of suppressing the bleeding of the adhesive component. That is, in the process of forming the curable adhesive layer from the coating film formed from the curable adhesive composition, the crosslinking agent (E) reacts with the reactive functional group of the binder resin (a) to form a crosslinked structure in the coating film, whereby the curable adhesive layer which is not easily flowable even when heated can be formed. As a result, the formed curable adhesive layer is less likely to cause a phenomenon in which the adhesive component oozes out from the end portion in the bonding step of bonding the curable adhesive layer to an adherend such as a circuit board by curing the curable adhesive layer to adhere to the adherend. In addition, from the viewpoint of forming a curable adhesive sheet adjusted so as to satisfy the above-described elements (I) and (III), the composition containing the crosslinking agent (E) is also preferable.
The crosslinking agent (E) may be used alone or in combination of 2 or more.
In the curable adhesive composition used in one embodiment of the present invention, the content of the component (E) is preferably 0.01 part by mass or more, more preferably 0.03 part by mass or more, more preferably 0.05 part by mass or more, more preferably 0.07 part by mass or more, more preferably 0.10 part by mass or more, more preferably 0.15 part by mass or more, more preferably 0.20 part by mass or more, more preferably 0.25 part by mass or more, particularly preferably 0.30 part by mass or more, and further preferably 10.0 parts by mass or less, more preferably 8.0 parts by mass or less, more preferably 6.0 parts by mass or less, more preferably 5.0 parts by mass or less, more preferably 4.0 parts by mass or less, more preferably 3.0 parts by mass or less, more preferably 2.5 parts by mass or less, more preferably 2.0 parts by mass or less, particularly preferably 1.5 parts by mass or less, relative to 100 parts by mass of the total amount of the component (a).
The molecular weight of the crosslinking agent (E) used in one embodiment of the present invention is preferably 1000 or less, more preferably 800 or less, still more preferably 700 or less, still more preferably 600 or less, particularly preferably 500 or less, from the viewpoint of being a composition that can enhance the reaction probability with the component (a), can easily form a crosslinked structure, and can form a curable adhesive layer having a higher effect of inhibiting bleeding of the adhesive component, and is preferably 100 or more, more preferably 150 or more, still more preferably 200 or more, still more preferably 250 or more, particularly preferably 300 or more, from the viewpoint of being a composition that can be adjusted to have the crosslinking agent (E) retained in the curable adhesive layer by heating in a drying step for forming the curable adhesive layer, and can exhibit the effect obtained by adding the crosslinking agent (E).
The crosslinking agent (E) used in one embodiment of the present invention is suitably selected according to the kind of the reactive functional group contained in the component (a), and examples thereof include: isocyanate-based crosslinking agents, epoxy-based crosslinking agents, metal chelate-based crosslinking agents, aziridine-based crosslinking agents, and the like.
Of these, the crosslinking agent (E) used in one embodiment of the present invention is preferably at least 1 selected from the group consisting of an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent and a metal chelate-based crosslinking agent from the viewpoint of storage stability.
In addition, the crosslinking agent (E) used in one embodiment of the present invention is preferably a crosslinking agent having an isocyanurate skeleton from the viewpoint of being a composition capable of forming a cured product having further improved low dielectric characteristics.
The isocyanate-based crosslinking agent is preferably a compound having 2 or more isocyanate groups in the molecule, and examples thereof include: 2, 4-toluene diisocyanate, 2, 6-toluene diisocyanate, hydrogenated xylene diisocyanate, 1, 5-pentamethylene diisocyanate, 1, 6-hexamethylene diisocyanate, diphenylmethane-4, 4-diisocyanate, isophorone diisocyanate, 1, 3-bis (isocyanatomethyl) cyclohexane, tetramethylxylylene diisocyanate, 1, 5-naphthalene diisocyanate, triphenylmethane triisocyanate, adducts of these polyisocyanate compounds with polyol compounds such as trimethylolpropane, biuret or isocyanurate of these polyisocyanate compounds, and the like.
The epoxy crosslinking agent is preferably a compound having 2 or more epoxy groups in the molecule, and examples thereof include: 1, 3-bis (N, N-diglycidyl aminomethyl) cyclohexane, N, N, N ', N' -tetraglycidyl m-xylylenediamine, ethylene glycol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, diglycidyl aniline, diglycidyl amine, and the like.
Examples of the metal chelate-based crosslinking agent include: chelating compounds having metal ions that act as crosslinking points. Examples of the metal ion include: aluminum ion, zirconium ion, titanium ion, zinc ion, iron ion, tin ion, and the like.
Among these, the metal chelate crosslinking agent is preferably an aluminum chelate compound, and examples thereof include: aluminum tris (acetylacetonate), aluminum bis (ethylacetoacetate), diisopropoxyaluminum monooleyl acetoacetate, monoisopropoxyaluminum dioleylacetoacetate, and the like.
Among these, the crosslinking agent (E) used in one embodiment of the present invention is preferably an isocyanate-based crosslinking agent, more preferably an isocyanurate of a polyisocyanate compound, and further preferably 1 or more selected from the group consisting of an isocyanurate of 1, 5-pentamethylene diisocyanate [1,3, 5-tris (5-isocyanatopentyl) -1,3, 5-triazine-2, 4, 6-trione ] and an isocyanurate of 1, 6-hexamethylene diisocyanate [1,3, 5-tris (6-isocyanatohexyl) -1,3, 5-triazine-2, 4, 6-trione ] from the viewpoint of a composition which becomes a curable adhesive layer having a higher effect of suppressing bleeding of an adhesive component and a composition which becomes a cured product having further improved low dielectric characteristics.
< Component (F): silane coupling agent >, and method for producing the same
The curable adhesive composition used in one embodiment of the present invention preferably further contains a silane coupling agent (F).
By forming the composition containing the silane coupling agent, a cured product having further improved adhesive strength can be formed.
The silane coupling agent (F) may be used alone or in combination of 2 or more.
In the curable adhesive composition used in one embodiment of the present invention, the content of the component (F) is preferably 0.001 part by mass or more, more preferably 0.005 part by mass or more, more preferably 0.01 part by mass or more, more preferably 0.03 part by mass or more, more preferably 0.05 part by mass or more, more preferably 0.07 part by mass or more, more preferably 0.10 part by mass or more, more preferably 0.12 part by mass or more, particularly preferably 0.15 part by mass or more, and further preferably 6.0 parts by mass or less, more preferably 5.0 parts by mass or less, more preferably 4.0 parts by mass or less, more preferably 3.0 parts by mass or less, more preferably 2.0 parts by mass or less, more preferably 1.5 parts by mass or less, more preferably 1.0 parts by mass or less, more preferably 0.80 parts by mass or less, particularly preferably 0.60 parts by mass or less, based on 100 parts by mass of the total amount of the component (a).
The silane coupling agent (E) used in one embodiment of the present invention is preferably an organosilicon compound having at least 1 alkoxysilyl group in the molecule.
Specific examples of the silane coupling agent include: silane coupling agents having a (meth) acryloyl group, such as 3-methacryloxypropyl methyl dimethoxy silane, 3-methacryloxypropyl trimethoxy silane, 3-methacryloxypropyl methyl diethoxy silane, 3-methacryloxypropyl triethoxy silane, and 3-acryloxypropyl trimethoxy silane; silane coupling agents having a vinyl group such as vinyltrimethoxysilane, vinyltriethoxysilane, dimethoxymethylvinylsilane, diethoxymethylvinylsilane, trichlorovinylsilane, and vinyltris (2-methoxyethoxy) silane; silane coupling agents having an epoxy group, such as 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropyl methyldiethoxysilane, 3-glycidoxypropyl triethoxysilane, and 8-glycidoxypropyl trimethoxysilane; silane coupling agents having a styrene group such as p-styryl trimethoxysilane and p-styryl triethoxysilane; silane coupling agents having an amino group such as hydrochloride salts of N- (2-aminoethyl) -3-aminopropyl methyldimethoxy silane, N- (2-aminoethyl) -3-aminopropyl trimethoxy silane, N- (2-aminoethyl) -3-aminopropyl triethoxy silane, 3-aminopropyl trimethoxy silane, 3-triethoxysilyl-N- (1, 3-dimethyl/butylene) propylamine, N-phenyl-3-aminopropyl trimethoxy silane, N- (vinylbenzyl) -2-aminoethyl-3-aminopropyl trimethoxy silane; silane coupling agents having an ureido group such as 3-ureidopropyltrimethoxysilane and 3-ureidopropyltriethoxysilane; silane coupling agents having halogen atoms such as 3-chloropropyl trimethoxysilane and 3-chloropropyl triethoxysilane; mercapto silane coupling agents such as 3-mercaptopropyl methyl dimethoxy silane and 3-mercaptopropyl trimethoxy silane; silane coupling agents having a thioether group, such as bis (trimethoxysilylpropyl) tetrasulfide and bis (triethoxysilylpropyl) tetrasulfide; silane coupling agents having an isocyanate group, such as 3-isocyanatopropyl trimethoxysilane and 3-isocyanatopropyl triethoxysilane; silane coupling agents having an allyl group, such as allyl trichlorosilane, allyl triethoxysilane, and allyl trimethoxysilane; and silane coupling agents having a hydroxyl group such as 3-hydroxypropyl trimethoxysilane and 3-hydroxypropyl triethoxysilane.
< Cyclic Ether Compounds >
The curable adhesive composition used in one embodiment of the present invention may be a composition further containing a cyclic ether compound.
The cyclic ether compound may be any compound having a cyclic ether group.
Examples of the cyclic ether group include: ethylene oxide (epoxy), propylene oxide (oxetanyl), tetrahydrofuran, tetrahydropyranyl, and the like.
In the present specification, the ethylene oxide group includes groups having an ethylene oxide structure such as a glycidyl group, a glycidyl ether group, and an epoxycyclohexyl group.
The cyclic ether compound may be used alone or in combination of 2 or more kinds.
The cyclic ether compound-containing composition has a property of forming a cured product excellent in adhesive strength, but on the other hand, the cured product tends to have a large relative dielectric constant or dielectric loss tangent, and low dielectric characteristics tend to be inferior to those of a composition containing the above-mentioned component (B) or component (C) and not containing the cyclic ether compound.
In the curable adhesive composition used in one embodiment of the present invention, the content of the cyclic ether compound may be set to less than 5.0 mass%, less than 3.0 mass%, less than 1.0 mass%, less than 0.50 mass%, less than 0.10 mass%, less than 0.010 mass%, less than 0.0010 mass%, less than 0.00010 mass%, or less than 0.000010 mass% with respect to the total amount (100 mass%) of the active ingredients of the curable adhesive composition.
In the curable adhesive composition used in one embodiment of the present invention, the content of the cyclic ether compound may be set to less than 5.0 parts by mass, less than 3.0 parts by mass, less than 1.0 parts by mass, less than 0.50 parts by mass, less than 0.10 parts by mass, less than 0.010 parts by mass, less than 0.0010 parts by mass, less than 0.00010 parts by mass, or less than 0.000010 parts by mass, relative to 100 parts by mass of the total amount of the components (a) to (C) contained in the curable adhesive composition.
< Inorganic filler >)
The curable adhesive composition used in one embodiment of the present invention may further contain an inorganic filler, or may be a composition containing no inorganic filler.
Examples of the inorganic filler include: silica, alumina, talc, aluminum hydroxide, magnesium hydroxide, titanium oxide, mica, aluminum borate, barium sulfate, boron nitride, forsterite, zinc oxide, magnesium oxide, calcium carbonate, and the like.
These inorganic fillers may be used alone or in combination of 2 or more.
However, in the curable adhesive composition used in one embodiment of the present invention, the smaller the content of the inorganic filler is, the more preferable.
In the curable adhesive composition used in one embodiment of the present invention, the content of the inorganic filler may be set to 0 to 30 mass%, 0 to 20 mass%, 0 to 10 mass%, 0 to 5.0 mass%, 0 to 2.0 mass%, 0 to 1.0 mass%, 0 to 0.1 mass%, 0 to 0.01 mass%, or 0 to 0.001 mass% with respect to the total amount (100 mass%) of the active ingredients of the curable adhesive composition.
In the curable adhesive composition used in one embodiment of the present invention, the content of the inorganic filler may be set to less than 50 parts by mass, less than 30 parts by mass, less than 10 parts by mass, less than 5.0 parts by mass, less than 1.0 parts by mass, less than 0.1 parts by mass, less than 0.01 parts by mass, less than 0.001 parts by mass, or less than 0.0001 parts by mass, relative to 100 parts by mass of the total amount of the components (a) to (C) contained in the curable adhesive composition.
< Other additives >)
The curable adhesive composition used in one embodiment of the present invention may contain other additives than the above components within a range that does not hinder the effects of the present invention.
Examples of other additives include: ultraviolet light absorbers, antistatic agents, light stabilizers, antioxidants, resin stabilizers, pigments, extenders, softeners, and the like.
These additives may be used alone or in combination of 2 or more.
The content of these additives may be appropriately set according to the kind of the additive.
For example, the content of each additive may be set to 0.001 to 30 parts by mass, 0.005 to 20 parts by mass, 0.01 to 10 parts by mass, or 0.03 to 5 parts by mass, relative to 100 parts by mass of the total amount of the component (a) contained in the curable adhesive composition.
< Active ingredient of liquid >
The curable adhesive composition used in one embodiment of the present invention preferably contains an active ingredient that is liquid at 25 ℃. The adhesiveness of the curable adhesive layer formed can be improved by preparing a composition containing a liquid active ingredient.
In the curable adhesive composition used in one embodiment of the present invention, the content of the active ingredient which is liquid at 25 ℃ is preferably 7.0% by mass or more, more preferably 10% by mass or more, still more preferably 12% by mass or more, and the content of the active ingredient which is liquid at 25 ℃ is further increased, so that the peel force (R1) and the peel force (R2) tend to be increased, from the viewpoint of the composition being capable of forming a curable adhesive layer excellent in adhesiveness, the curable adhesive sheet is preferably 50% by mass or less, more preferably 35% by mass or less, still more preferably 25% by mass or less, from the viewpoint of adjusting the curable adhesive sheet so as to satisfy the above-described element (I) or (III).
From the standpoint of forming a composition capable of forming a curable adhesive layer excellent in adhesion and forming a composition capable of forming a cured product having further improved low dielectric characteristics and adhesive strength, at least 1 of the polyfunctional compounds (C) contained in the curable adhesive composition used in one embodiment of the present invention is preferably an active ingredient that is liquid at 25 ℃.
In the curable adhesive composition used in one embodiment of the present invention, the content of the polyfunctional compound (C) is preferably 70 mass% or more, more preferably 80 mass% or more, still more preferably 85 mass% or more, based on the total amount (100 mass%) of the active ingredient that is liquid at 25 ℃, and may be generally 100 mass% or less, preferably 99.0 mass% or less, more preferably 98.0 mass% or less.
< Dilution solvent >)
The curable adhesive composition used in one embodiment of the present invention may be further added with a diluting solvent to be in the form of a solution.
Examples of the diluent solvent used in one embodiment of the present invention include: aromatic hydrocarbon solvents such as benzene and toluene; ester solvents such as ethyl acetate and butyl acetate; ketone solvents such as acetone, butanone, and methyl isobutyl ketone; aliphatic hydrocarbon solvents such as n-pentane, n-hexane and n-heptane; alicyclic hydrocarbon solvents such as cyclopentane, cyclohexane and methylcyclohexane.
These diluting solvents may be used alone or in combination of 2 or more.
The diluent solvent may be used as it is for the synthesis of the component (A) or (B), or may be added with 1 or more solvents other than the solvent used for the synthesis of the component (A) or (B).
In the case where the curable adhesive composition used in one embodiment of the present invention is in the form of a solution, the concentration of the active ingredient of the curable adhesive composition is suitably set to a desired viscosity in view of coatability and the like, and is preferably 3.0% by mass or more, more preferably 10% by mass or more, and is preferably 70% by mass or less, more preferably 50% by mass or less, relative to the total amount (100% by mass) of the curable adhesive composition.
[ Method for producing curable adhesive sheet ]
As a method for producing a curable adhesive sheet according to an embodiment of the present invention, the curable adhesive composition described above can be applied to a release layer of a 1 st release film or a2 nd release film by a known application method.
From the viewpoint of improving the coating property on the release film, the curable adhesive composition is preferably diluted with a diluting solvent to be in the form of a solution.
Examples of the method for applying the curable adhesive composition include: spin coating, spray coating, bar coating, blade coating, roll coating, blade coating, die coating, gravure coating, and the like.
It is preferable to perform a drying treatment after the curable adhesive composition is applied to form a coating film.
Examples of the drying treatment method include: hot air drying, hot roller drying, infrared irradiation, and the like.
The drying condition of the formed coating film is preferably to heat at a temperature of 80 to 150 ℃ for 30 seconds to 5 minutes (preferably 40 seconds to 3 minutes, more preferably 45 seconds to 2 minutes) and dry. Through this drying step, a curable adhesive layer can be formed on the release layer of the 1 st release film or the 2 nd release film. Further, another release film is laminated on the exposed surface of the formed curable adhesive layer, thereby forming a curable adhesive sheet according to an embodiment of the present invention. From the viewpoint of easy obtaining of a curable adhesive sheet satisfying the element (II), it is preferable to apply the curable adhesive composition onto the 2 nd release film and laminate the 1 st release film on the exposed surface of the formed curable adhesive layer.
When the curable adhesive composition for forming the curable adhesive layer contains the crosslinking agent (E), it is preferable to perform the air-drying step for a predetermined period of time (for example, about 1 to 14 days) in order to complete the crosslinking reaction.
[ Method for Using curable adhesive sheet, method for producing Circuit Board with cured product ]
The cured product obtained by curing the curable adhesive layer of the curable adhesive sheet according to one embodiment of the present invention has high adhesive strength and also has excellent low dielectric characteristics in a high frequency range.
Therefore, the curable adhesive sheet according to an embodiment of the present invention is suitable for use in forming a member in a device requiring low dielectric characteristics, and is particularly suitable for use as a cover film for protecting a circuit board.
Examples of the circuit board include: flexible printed wiring boards (FPCs), and the like.
Further, since the curable adhesive layer of the curable adhesive sheet according to one embodiment of the present invention has the above-described characteristics, the present invention can also provide the following [1] and [2].
[1] A method for using a curable adhesive sheet, comprising the following bonding steps: the curable adhesive layer of the curable adhesive sheet according to one aspect of the present invention is bonded to a circuit board, and the curable adhesive layer is cured to form a cured product, and the cured product is bonded to the circuit board.
[2] A method for manufacturing a circuit board with a cured product, comprising the following bonding steps: the curable adhesive layer of the curable adhesive sheet according to one aspect of the present invention is bonded to a circuit board, and the curable adhesive layer is cured to form a cured product, and the cured product is bonded to the circuit board.
In the above-mentioned [1] and [2], the method of curing the curable adhesive layer into a cured product may be adjusted according to the type of the reactive curing agent such as component (D), and may be a thermosetting method or a photo-curing method, and may be selected according to the type of the component contained in the curable adhesive composition as a material for forming the curable adhesive layer. But is preferably a thermal curing process.
The heating temperature in the heat curing is preferably 80 to 200 ℃, more preferably 90 to 190 ℃, still more preferably 100 to 180 ℃, and the heating time is preferably 10 minutes to 12 hours, more preferably 30 minutes to 6 hours, still more preferably 40 minutes to 3 hours.
In addition, when heat curing is performed, heat pressing is preferably performed. The pressure at the time of hot pressing is preferably 0.1 to 10MPa, more preferably 0.5 to 8.0MPa, and still more preferably 1.0 to 5.0MPa.
In the case of curing the curable adhesive layer by the photo-curing method, the curable adhesive layer can be cured by irradiation with energy rays such as ultraviolet rays.
Examples
The present invention will be described in more detail with reference to the following examples. The present invention is not limited to the following examples.
The physical properties are measured by the following methods.
[ Number average molecular weight (Mn) ]
The measurement was performed under the following conditions using a gel permeation chromatography apparatus (product name "HLC-8320GPC" manufactured by Tosoh Co., ltd.) and the value measured by conversion into standard polystyrene was used.
(Measurement conditions)
Column: "TSK gel guard column super H-H", "TSK gel super HM-H" and "TSK gel super H2000" were connected in this order (all manufactured by Tosoh Co., ltd.);
Column temperature: 40 ℃;
Developing solvent: tetrahydrofuran;
Flow rate: 1.0 mL/min.
[ Release force (R1) ]
The curable adhesive sheet to be measured was cut into a size of 150m×50mm in the vertical direction, and a test sample was prepared.
Then, one adhesive surface of the double-sided tape was stuck to the surface of the test sample 2 nd release film opposite to the surface in contact with the curable adhesive layer, and the other adhesive surface of the double-sided tape was laminated on the surface of the metal plate, and press-bonding was performed.
Then, the 1 st release film to be measured as a release force was peeled from the test sample fixed to the metal plate at a peeling angle of 180℃and a peeling speed of 300 mm/min using a precision universal tester (product name "Autograph AG-IS" manufactured by Shimadzu corporation) at a temperature of 23℃and a relative humidity of 50%, and the value measured at this time was defined as "peeling force (R1)".
[ Peel force (R2) ]
The 1 st release film was removed from the curable adhesive sheet to be measured, and the exposed adhesive surface was laminated on the surface of a polyimide film (Kapton 100H, manufactured by dolby eastern corporation) having a thickness of 25 μm, and the resultant film was laminated at 100℃using a thermal laminator. Then, the curable adhesive sheet was cut into a size of 150m×50mm in the longitudinal direction and 50mm in the transverse direction together with the polyimide film, and test samples were produced. One adhesive surface of the double-sided tape was adhered to the surface of the polyimide film of the test sample opposite to the surface on which the curable adhesive layer was laminated, and the other adhesive surface of the double-sided tape was laminated on the surface of the metal plate, and the laminated film was pressed. The test sample was subjected to a peel test in the same manner as in the measurement of the peel force (R1). That is, the 2 nd release film to be measured as a release force was peeled from the test sample fixed to the metal plate under conditions of a release angle of 180℃and a release speed of 300 mm/min using the precision universal tester under an environment having a temperature of 23℃and a relative humidity of 50%, and the value measured at this time was defined as "release force (R2)".
Production examples 1 to 2
(1) Preparation of curable adhesive composition
The components shown in table 1 were mixed in the amounts (effective component ratios) shown in table 1 and dissolved in toluene to prepare curable adhesive compositions (1) to (2) so as to achieve the predetermined effective component concentrations.
Details of the components used for preparing the curable adhesive compositions (1) to (2) are as follows.
< Component (A): adhesive resin >, adhesive resin
"Modified polyolefin": a solution (product name "Unistole H-200" manufactured by mitsunobu chemical company) containing a maleic anhydride-modified alpha-olefin polymer (solid at 25 ℃) with mn=47,000.
< Component (B): polyphenylene ether resin
"Polyphenylene ether resin (b 1)": a solution (product name "OPE-2St 2200", manufactured by Mitsubishi gas chemical Co., ltd.) containing a vinylbenzyl-modified polyphenylene ether (compound represented by the above general formula (b-4), which is a solid at 25 ℃ C.) having Mn=2,200.
"Polyphenylene ether resin (b 2)": a solution (product name "OPE-2St 1200", manufactured by Mitsubishi gas chemical Co., ltd.) containing a vinylbenzyl-modified polyphenylene ether (compound represented by the above general formula (b-4), which is a solid at 25 ℃).
< Component (C): polyfunctional Compound
"Polyfunctional Compound": r a in the general formula (c-11) is an alkyl group having 8 to 15 carbon atoms, and has an isocyanurate skeleton. The product name "L-DAIC", manufactured by four chemical industry co., ltd, molecular weight= 377.27, is a liquid at 25 ℃.
< Component (D): cationic polymerization initiator >, and
"Thermal cationic polymerization initiator": the thermal cationic polymerization initiator (product name "San-Aid SI-B3" manufactured by Sannew chemical industry Co., ltd.) was a solid at 25 ℃.
< Ingredient (E): crosslinking agent >
"Isocyanate-based crosslinking agent": 1,3, 5-tris (5-isocyanatopentyl) -1,3, 5-triazine-2, 4, 6-trione (product name "Stabio D-370N", manufactured by Mitsui chemical Co., ltd.), molecular weight=462, being liquid at 25 ℃.
< Component (F): silane coupling agent >, and method for producing the same
"Silane coupling agent": 8-glycidoxy-octyl trimethoxysilane (product name "KBM4803", xinyue chemical Co., ltd.) is a liquid at 25 ℃.
TABLE 1
TABLE 1
Examples 1 to 2 and comparative examples 1 to 2
The release films used in the following examples and comparative examples and curable adhesive compositions as materials for forming the curable adhesive layers are as follows.
<1 St Release film >
Non-silicone release film (1): product names "PC38 AL-5", manufactured by Lintec corporation, a non-silicone release film having a release layer formed of an alkyd-based release agent on a polyethylene terephthalate (PET) film foamed to be white, thickness: 38 μm.
< 2 Nd Release film >
Non-silicone release film (2): product names "SP-PET50 AL-5", manufactured by Lintec corporation, a non-silicone release film having a release layer formed of an alkyd-based release agent on a colorless PET film, thickness: 50 μm.
Non-silicone release film (3): product names "SP-PET75 AL-5", manufactured by Lintec corporation, a non-silicone release film having a release layer formed of an alkyd-based release agent on a colorless PET film, thickness: 75 μm.
Material for forming curable adhesive layer
Curable adhesive composition (1): the curable adhesive composition (1) prepared in production example 1 was prepared with the composition shown in table 1.
Curable adhesive composition (2): the curable adhesive composition (2) prepared in production example 2 with the composition shown in table 1.
The curable adhesive composition described in table 1 was applied to the release layer of the 2 nd release film described in table 2 to form a coating film, and the coating film was dried to form a curable adhesive layer having a thickness of 25 μm.
The exposed surface of the formed curable adhesive layer was then bonded to the release layer of the 1 st release film described in table 2, to prepare a curable adhesive sheet.
The peel forces (R1) and (R2) were measured by the above-described method using the prepared curable adhesive sheet. The results are shown in Table 2.
The dielectric loss tangent of the cured product obtained by curing the curable adhesive layer and the peelability of the 1 st peeling film were evaluated according to the following evaluation methods. The results of these are also shown in Table 2.
[ Dielectric loss tangent of cured product ]
A plurality of the produced curable adhesive sheets were prepared, and a plurality of the curable adhesive layers were stacked to form a curable adhesive layer having a thickness of about 1mm, thereby obtaining a laminate in which a2 nd release film, a curable adhesive layer having a thickness of about 1mm, and a1 st release film were stacked in this order.
Then, the laminate was heated at 160 ℃ for 1 hour to cure the curable adhesive layer into a cured product, and the 1 st release film and the 2 nd release film were removed to obtain a cured product as a sample for measurement.
For the obtained measurement sample, the dielectric loss tangent of the cured product at 23℃and 1GHz was measured using RF IMPEDANCE MATERIAL Analyzer (product name "E4991A", manufactured by Keysight Technologies). In the present specification, 1GHz is used as an example of the high frequency region.
[ Evaluation of peelability of the 1 st peeling film ]
The ease of peeling was evaluated in peeling only the 1 st release film from the produced curable adhesive sheet according to the following criteria.
A: the 1 st release film was very easily released, and there was no problem in terms of operability.
F: when the 1 st release film is to be peeled, reworking occurs 1 or more times, and there is a problem in operability.
TABLE 2
TABLE 2
The following results are shown in Table 2: in the curable adhesive sheets produced in examples 1 and 2, the 1 st release film was easily peeled off and the handleability was excellent as compared with comparative examples 1 and 2. Further, since the curable adhesive sheets produced in examples 1 and 2 use a non-silicone release agent, the transfer of the silicone component to the adherend is not caused, and thus contamination of the adherend can be suppressed.
Symbol description
1: A curable adhesive sheet;
10: a curable adhesive layer;
10a, 10b: a surface;
21: 1 st release film;
211: a peeling layer;
212: a resin film;
22: a2 nd release film;
221: a peeling layer;
222: and (3) a resin film.

Claims (9)

1. A curable adhesive sheet comprising: a curable adhesive layer capable of forming a cured product having a dielectric loss tangent of 0.01 or less at 23 ℃ and 1 GHz; a 1 st release film and a 2 nd release film sandwiching both sides of the curable adhesive layer,
The 1 st release film and the 2 nd release film have: a resin film, and a release layer formed on one surface of the resin film by a non-silicone release agent and contacting with the surface of the curable adhesive layer,
The curable adhesive sheet satisfies the following element (I):
element (I): the peel force (R1) when the 1 st release film is peeled from the curable adhesive layer at a peel angle of 180 DEG and a peel speed of 300 mm/min is 250mN/50mm or less.
2. The curable adhesive sheet according to claim 1, which further satisfies the following element (II):
Element (II): the peel force (R1) is smaller than the peel force (R2) when the 2 nd release film is peeled from the curable adhesive layer at a peel angle of 180 DEG and a peel speed of 300 mm/min.
3. The curable adhesive sheet according to claim 2, which further satisfies the following element (IIa):
Element (IIa): the ratio (R1)/(R2) of the peeling force (R1) to the peeling force (R2) is 0.97 or less.
4. The curable adhesive sheet according to any one of claims 1 to 3, which further satisfies the following element (III):
Element (III): the peel force (R2) when the 2 nd release film is peeled from the curable adhesive layer at a peel angle of 180 DEG and a peel speed of 300 mm/min is 300mN/50mm or less.
5. The curable adhesive sheet according to any one of claims 1 to 4, wherein the non-silicone release agent for forming at least one release layer of the 1 st release film and the 2 nd release film is an alkyd release agent.
6. The curable adhesive sheet according to any one of claims 1 to 5, wherein the curable adhesive layer is a layer formed of a curable adhesive composition containing an adhesive resin (A).
7. The curable adhesive sheet according to claim 6, wherein the curable adhesive composition further comprises a polyphenylene ether resin (B).
8. The curable adhesive sheet according to any one of claims 1 to 7, wherein the resin film (1) constituting the 1 st release film is a colored resin film.
9. The curable adhesive sheet according to any one of claims 1 to 8, wherein the resin film (2) constituting the 2 nd release film and the resin film (1) constituting the 1 st release film are visually distinguishable.
CN202280063976.6A 2021-09-30 2022-09-30 Curable adhesive sheet Pending CN118043416A (en)

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JP2021-161687 2021-09-30
PCT/JP2022/036714 WO2023054676A1 (en) 2021-09-30 2022-09-30 Curable adhesive sheet

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TW (1) TW202332749A (en)
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005332516A (en) * 2004-05-21 2005-12-02 Sony Disc & Digital Solutions Inc Manufacturing apparatus and manufacturing method of disk
KR101625250B1 (en) * 2008-09-30 2016-05-27 린텍 가부시키가이샤 Film-peeling method, process for production of optical film, film-peeling mechanism, and apparatus for production of optical film
JP2013067743A (en) * 2011-09-26 2013-04-18 Mitsubishi Plastics Inc Substrate-less double-sided adhesive sheet
JP6081123B2 (en) * 2011-10-08 2017-02-15 三菱樹脂株式会社 Substrate-less double-sided adhesive sheet
JP2015004009A (en) * 2013-06-21 2015-01-08 味の素株式会社 Resin compositions
WO2021106847A1 (en) * 2019-11-28 2021-06-03 東洋紡株式会社 Adhesive film, laminate, and printed wiring board

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