KR20080029837A - Adhesive composition and substrate for flexible print wiring board - Google Patents

Abstract

An adhesive composition is provided to form an adhesive layer having excellent electric characteristics, especially low dielectric constant and low dielectric loss while maintaining sufficient adhesive performance. An adhesive composition contains (A) a copolymer including (a-1) a structural unit derived from a monomer having at least two ethylenically polymerizable unsaturated groups and (a-2) a structural unit derived from a monomer having an alcoholic hydroxyl group, (B) a thermosetting resin, and (C) a hardener. A substrate for a flexible print wiring board includes an insulating film layer, a circuit substrate, and an adhesive layer which is formed by the adhesive composition and is disposed between the insulating film layer and the circuit substrate to glue the insulating film layer and the circuit substrate together.

Description

Adhesive composition and substrate for flexible printed wiring boards {Adhesive Composition and Substrate for Flexible Print Wiring Board}

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to an adhesive composition and a substrate for a flexible printed wiring board, and more particularly, to an adhesive composition capable of forming an adhesive layer that exhibits excellent electrical properties such as excellent low dielectric constant and low dielectric loss and sufficient adhesive force, and a flexible printed wiring board using the same. It relates to a substrate.

Background Art In recent years, with the light and short size reduction of communication devices such as electronic devices and mobile phones, flexible circuit boards, which are advantageous for circuit design, have been used for most of these communication devices. This flexible circuit board has a structure in which the insulating film layer containing polyimide and the copper foil layer which is a circuit board are integrated through the adhesive bond layer, for example. The said circuit board can be manufactured by etching copper foil.

The adhesive composition for forming the adhesive layer contains acrylonitrile for the purpose of imparting sufficient adhesive strength and toughness to the thermosetting resin which is considered to have good compatibility with thermosetting resins such as epoxy resins and is generally hard and vulnerable. It is known to contain a copolymer (for example, an acrylonitrile-butadiene copolymer or a carboxy-modified acrylonitrile-butadiene copolymer, etc.) to be described (for example, Patent Documents 1 to 3 below).

[Patent Document 1] Japanese Unexamined Patent Publication No. 10-102025

[Patent Document 2] Japanese Patent Application Laid-Open No. 2002-235063

[Patent Document 3] Japanese Unexamined Patent Publication No. 2003-165898

However, when the copolymer containing acrylonitrile contained acrylonitrile of a predetermined amount or more, the electrical properties of the formed adhesive layer, in particular, low dielectric constant and low dielectric loss, were inferior. In the future, the densification of the flexible circuit is expected to proceed, and in the densification of the flexible circuit, not only the adhesive performance but also the excellent electrical characteristics (especially low dielectric constant and low dielectric loss) are urgently required.

This invention is made | formed in view of the problem which this prior art has, and the subject made | formed as (A) (a-1) structural unit derived from the monomer which has two or more ethylenically polymerizable unsaturated groups, and (a-2) A) a copolymer having a structural unit derived from a monomer having an alcoholic hydroxyl group, (B) a thermosetting resin, and (C) a curing agent, which maintains sufficient adhesive performance in the densification of a flexible circuit and has excellent electrical properties. It is to provide a composition.

 MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to achieve the said subject, the present inventors discovered that it is possible to achieve the said subject by containing a specific copolymer, a thermosetting resin, and a hardening | curing agent, and came to complete this invention.

That is, according to this invention, the adhesive composition and the board | substrate for flexible printed wiring boards shown below are provided.

[1] (A) (a-1) Copolymer having structural unit derived from monomer having two or more ethylenically polymerizable unsaturated groups and (a-2) monomer having alcoholic hydroxyl group, (B ) An adhesive composition containing a thermosetting resin and (C) a curing agent.

[2] The ratio of the structural unit (a-1) is from 50 to 95 mol% based on 100 mol% of the total structural units constituting the (A) copolymer, and the ratio of the structural unit (a-2) is above. (A) Adhesive composition as described in said [1] which is 5-50 mol% with respect to 100 mol% of all the structural units which comprise a copolymer.

[3] The copolymer (A) further comprises a structural unit derived from at least one member selected from the group consisting of (a-3) styrene, styrene derivatives, (meth) acrylic acid, and (meth) acrylic acid derivatives. Adhesive composition as described in said [1].

[4] The ratio of the structural unit (a-1) is 50 to 90 mol% with respect to 100 mol% of the total structural units constituting the (A) copolymer, and the ratio of the structural unit (a-2) is (A) It is 5-45 mol% with respect to 100 mol% of all the structural units which comprise a copolymer, and the ratio of the said (a-3) structural unit is 100 mol% of all the structural units which comprise the said (A) copolymer. The adhesive composition as described in said [3] which is 1-25 mol% with respect to.

[5] The adhesive composition according to the above [1], wherein the structural unit (a-1) is a structural unit derived from a diene monomer.

[6] The adhesive composition according to the above [1], wherein the structural unit (a-2) is a structural unit derived from hydroxyalkyl (meth) acrylate.

[7] The ratio of the structural unit derived from (a-4) acrylonitrile contained in the (A) copolymer is 5 mol% or less with respect to 100 mol% of the entire structural units constituting the (A) copolymer. Adhesive composition as described in [1].

[8] The adhesive composition according to the above [1], containing an epoxy resin as the (B) thermosetting resin.

[9] The adhesive composition according to the above [1], wherein the content of the alkali metal ion contained in the (A) copolymer is 50 ppm or less.

[10] an adhesive layer formed of an insulating film layer, a circuit board, and the adhesive composition according to the above [1], and disposed between the insulating film layer and the circuit board to adhere the insulating film layer and the circuit board. The board | substrate for flexible printed wiring boards provided.

The adhesive composition of this invention exhibits the effect which can form the adhesive bond layer which has the outstanding electrical characteristics (especially low dielectric constant and low dielectric loss), maintaining sufficient adhesive performance.

Since the board | substrate for flexible printed wiring boards of this invention is equipped with the adhesive bond layer which has the outstanding electrical characteristic (especially low dielectric constant and low dielectric loss), maintaining sufficient adhesive performance, it can achieve thinning (lightening) and high density. It is effective.

Best Mode for Carrying Out the Invention The best embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments, and is based on the common knowledge of those skilled in the art without departing from the spirit of the present invention. It is to be understood that modifications, improvements, and the like, as appropriate, are included in the scope of the present invention.

[1] adhesive compositions:

The adhesive composition of this invention is a copolymer which has the structural unit derived from the monomer which has (A) (a-1) monomer which has two or more ethylenically polymerizable unsaturated groups, and (a-2) alcoholic hydroxyl group. (Hereinafter, it may describe as "(A) copolymer"), (B) thermosetting resin, and (C) hardening | curing agent. By such a structure, the effect which can form the adhesive bond layer which has the outstanding electrical characteristics (especially low dielectric constant and low dielectric loss), maintaining sufficient adhesive performance is exhibited.

Moreover, the adhesive composition of this invention is (A) (a-1) structural unit derived from the monomer which has 2 or more of ethylenically polymerizable unsaturated groups, (a-2) structural unit derived from the monomer which has an alcoholic hydroxyl group, and (a-3) Copolymer containing structural units derived from at least one member selected from the group consisting of styrene, styrene derivatives, (meth) acrylic acid, and (meth) acrylic acid derivatives (hereinafter, "(A) copolymer" D), (B) thermosetting resin, and (C) a curing agent are preferable. With such a configuration, the adhesive layer having sufficient adhesive strength and heat resistance can be formed with an excellent adhesive layer having excellent electrical characteristics such as low dielectric constant and low dielectric loss. Hereinafter, each component is explained in full detail.

In addition, the structural unit derived from styrene and a styrene derivative may be described as "(a-3-1) structural unit" below, and the structural unit derived from a (meth) acrylic acid and a (meth) acrylic acid derivative is "( a-3-2) structural unit "may be described.

[1-1] (A) copolymer:

The (A) copolymer contained in the adhesive composition of the present invention is a structural unit derived from a monomer having two or more (a-1) ethylenically polymerizable unsaturated groups (hereinafter referred to as "(a-1) structural unit" And a structural unit derived from the monomer which has an alcoholic hydroxyl group (Hereinafter, it may describe as "(a-2) structural unit.").

The structural unit (a-1) is not particularly limited as long as it is derived from a monomer having two or more ethylenically polymerizable unsaturated groups. As a monomer which has 2 or more of said ethylenically polymerizable unsaturated groups, a diene monomer etc. are mentioned, for example, As a diene monomer, 1, 3- butadiene, dimethyl butadiene, chloroprene, 1, 3- pentadiene, isoprene, etc. Can be mentioned.

It is preferable that the ratio of the said (a-1) structural unit is 50-95 mol% with respect to 100 mol% of all the structural units which comprise the said (A) copolymer. More preferably, it is 55-85 mol%, Especially preferably, it is 60-85 mol%. When the ratio of the structural unit (a-1) is within the above range, the copolymer obtained has rubber elasticity and sufficient adhesive force is obtained. Moreover, when the ratio of the said (a-1) structural unit is less than 50 mol%, there exists a possibility that adhesive force may fall. On the other hand, when the ratio of (a-1) structural unit exceeds 95 mol%, compatibility with the thermosetting resin to mix | blend falls.

The structural unit (a-2) is not particularly limited as long as it is derived from a monomer having an alcoholic hydroxyl group. Conventionally, flexible circuit boards of communication devices, such as an electronic device and a mobile telephone, are equipped with the insulating film layer containing an epoxy resin, etc., and the circuit board containing a copper foil layer, etc., These insulating film layers and a circuit board are attached to an adhesive bond layer. Formed by bonding. This adhesive bond layer was formed with the composition which has a copolymer containing the structural unit derived from acrylonitrile for the reason that it has favorable compatibility with the epoxy resin which comprises an insulating film layer. Here, the (A) copolymer contained in the adhesive composition of this invention is the ratio of the structural unit (henceforth, it may describe as "(a-4) structural unit") derived from (a-4) acrylonitrile. Although it is 5 mol% or less, the structural unit (a-2) acts as a polarizing group of a copolymer by containing (a-2) structural unit. For this reason, the adhesive layer formed by the adhesive composition of this invention can acquire favorable compatibility with the insulating film layer containing an epoxy resin etc.

As the monomer having an alcoholic hydroxyl group for constituting the structural unit (a-2), for example, a (meth) acrylate having an alcoholic hydroxyl group is preferable. As a monomer which has the said alcoholic hydroxyl group, For example, hydroxyalkyl (meth) acrylates, such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate; 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol di (meth) acrylic Late monostearate, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate; Epoxy (meth) acrylates; Etc. can be mentioned. Epoxy (meth) acrylates can be obtained, for example, by reaction with diglycidyl ether of bisphenol A, diglycidyl ether of glycol, or the like (meth) acrylic acid, hydroxyalkyl (meth) acrylate, or the like. have.

It is preferable that the ratio of the said (a-2) structural unit is 5-50 mol% with respect to 100 mol% of all the structural units which comprise the said (A) copolymer. More preferably, it is 15-45 mol%, Especially preferably, it is 15-40 mol%. When the ratio of the structural unit (a-2) is within the above range, the resulting copolymer has good compatibility with the thermosetting resin to be blended, has toughness, and has sufficient adhesiveness.

On the other hand, the copolymer (A) may contain other structural units (hereinafter sometimes referred to as "other structural unit (α)") in addition to the structural units (a-1) and (a-2). have. The other structural unit (α) is not particularly limited as long as it is derived from a monomer copolymerizable with a monomer having two or more ethylenically polymerizable unsaturated groups and a monomer having an alcoholic hydroxyl group. Moreover, it is preferable that the ratio of other structural unit ((alpha)) is 5-30 mol% with respect to 100 mol% of all the structural units which comprise (A) copolymer. More preferably, it is 5-25 mol%, Especially preferably, it is 1-15 mol%. However, when the said other structural unit ((alpha)) is a structural unit derived from acrylonitrile, the ratio of the other structural unit ((alpha)) (structural unit derived from acrylonitrile) is with respect to 100 mol% of (A) copolymers. It is preferable that it is 5 mol% or less. On the other hand, most preferably, it does not contain a structural unit derived from acrylonitrile.

Other structural units (?) Include those derived from monomers such as monomers having a carboxyl group and monomers having an epoxy group.

Examples of the monomer having a carboxyl group include non-polymerizable polyhydric carboxylic acids such as unsaturated carboxylic acids such as (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, tetraconic acid and cinnamic acid, phthalic acid, succinic acid and adipic acid, and (meth) Free carboxyl group-containing esters, such as monoester with hydroxyl-containing unsaturated compounds, such as allyl alcohol and 2-hydroxyethyl (meth) acrylate, and its salt, etc. are mentioned.

As a monomer which has an epoxy group, (meth) allyl glycidyl ether, glycidyl (meth) acrylate, 3, 4- oxycyclohexyl (meth) acrylate, etc. are mentioned.

The (A) copolymer contained in the adhesive composition of the present invention is a structural unit derived from one or more selected from the group consisting of (a-3) styrene, styrene derivatives, (meth) acrylic acid, and (meth) acrylic acid derivatives ( Hereinafter, it is preferable to further have "(a-3) structural unit").

That is, the (A) copolymer contained in the adhesive composition of this invention is a structural unit ((a-1) structural unit) derived from the monomer which has two or more (a-1) ethylenically polymerizable unsaturated groups, (a- 2) a structural unit ((a-2) structural unit) derived from a monomer having an alcoholic hydroxyl group, and (a-3) styrene, a styrene derivative, a (meth) acrylic acid, and a (meth) acrylic acid derivative. It is preferable to have a structural unit (henceforth, it may describe as "(a-3) structural unit") derived from 1 or more types.

Flexible circuit boards used in communication devices such as electronic devices and mobile phones generate heat in accordance with the use of the communication devices. When the flexible circuit board generates heat (when the adhesive layer is heated), since the adhesive layer is decomposed, there is a problem that its adhesive force is lowered. Therefore, the adhesive bond layer provided in a flexible circuit board is required to have heat resistance.

In the adhesive composition of the present invention, the (A) copolymer containing has the structural unit (a-3), and thus, it is possible to form an adhesive layer having sufficient adhesive strength and excellent electrical properties such as low dielectric constant and low dielectric loss. At the same time, an adhesive layer having heat resistance can be formed.

More specifically, when the (A) copolymer contains a structural unit derived from styrene, a structural unit derived from a styrene derivative, or both of these structural units, it acts on high Tg of the (A) copolymer, The adhesive layer formed exhibits heat resistance. Moreover, when (A) copolymer contains the structural unit derived from (meth) acrylic acid, the structural unit derived from (meth) acrylic acid derivative, or both these structural units, the said structural unit reacts with (B) thermosetting resin. Since crosslinking density becomes high by this, the adhesive bond layer formed exhibits heat resistance. (B) The reaction with the thermosetting resin specifically forms a crosslinked structure by reacting a carboxyl group with an epoxy group. Since the crosslinking density is increased by this reaction, the adhesive layer formed exhibits heat resistance (the Tg of the cured product rises). do). On the other hand, the copolymer (A) contains structural units derived from styrene, structural units derived from styrene derivatives, or both of these structural units, thereby achieving high Tg and exhibiting excellent electrical properties.

In addition, the structural unit derived from styrene and a styrene derivative may be described as "(a-3-1) structural unit" below, and the structural unit derived from a (meth) acrylic acid and a (meth) acrylic acid derivative is "( a-3-2) structural unit "may be described. Hereinafter, the detail is demonstrated.

When the (A) copolymer contains the (a-3) structural unit, the (a-1) structural unit contained in the (A) copolymer can be exemplified as mentioned above.

When (A) copolymer contains (a-3) structural unit, the ratio of (a-1) structural unit is 50-90 mol% with respect to 100 mol% of all the structural units which comprise the said (A) copolymer. Is preferably. More preferably, it is 55-90 mol%, Especially preferably, it is 60-85 mol%. When the ratio of the structural unit (a-1) is in the above range, the copolymer obtained has rubber elasticity and sufficient adhesive force is obtained. Moreover, there exists a possibility that adhesive force may fall that the ratio of the said (a-1) structural unit is less than 50 mol%. On the other hand, when the ratio of (a-1) structural unit exceeds 95 mol%, there exists a possibility that compatibility with the thermosetting resin to mix | blend may fall.

When the (A) copolymer contains the (a-3) structural unit, the (a-2) structural unit contained in the (A) copolymer can be similarly exemplified above.

When (A) copolymer contains (a-3) structural unit, the ratio of (a-2) structural unit is 5-45 mol% with respect to 100 mol% of all the structural units which comprise the said (A) copolymer. Is preferably. More preferably, it is 7-30 mol%, Especially preferably, it is 10-20 mol%. When the ratio of the structural unit (a-2) is within the above range, the polymer obtained has good compatibility with the thermosetting resin to be blended, has toughness, and has sufficient adhesiveness.

(a-3) As the styrene and styrene derivatives that can be used to constitute the structural unit, for example, aromatic vinyls such as α-methylstyrene, o-methoxystyrene, p-hydroxystyrene, p-isopropenylphenol and the like The compound can be mentioned. Moreover, as a (meth) acrylic acid and a (meth) acrylic acid derivative which can be used to comprise the structural unit (a-3), for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, ( Butyl meth) acrylate, hexyl (meth) acrylate, lauryl (meth) acrylate, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, and the like. In addition, since (a-3) structural units are "a structural unit derived from 1 or more types chosen from the group which consists of a styrene, a styrene derivative, (meth) acrylic acid, and a (meth) acrylic acid derivative", these are used individually or 2 More than one species can be used simultaneously.

It is preferable that the ratio of (a-3) structural unit is 1-25 mol% with respect to 100 mol% of all the structural units which comprise the said (A) copolymer. More preferably, it is 1-20 mol%, Especially preferably, it is 1-18 mol%. When the ratio of the (a-3) structural unit is in the above range, the heat resistance of the cured product obtained from the adhesive composition is good.

When the (A) copolymer contains the (a-3) structural unit, the (A) copolymer has a structure other than the (a-1) structural unit, (a-2) the structural unit and the (a-3) structural unit. It may contain a unit (hereinafter, may be described as "other structural unit (β)"). As other structural unit ((beta)), it is chosen from the group which consists of a monomer which has 2 or more of said ethylenically polymerizable unsaturated groups, the monomer which has an alcoholic hydroxyl group, and styrene, a styrene derivative, (meth) acrylic acid, and a (meth) acrylic acid derivative. There is no restriction | limiting in particular if it originates in the monomer copolymerizable with 1 or more types.

Moreover, it is preferable that the ratio of other structural unit ((beta)) is 1-20 mol% with respect to 100 mol% of all the structural units which comprise (A) copolymer. More preferably, it is 1-15 mol%, Especially preferably, it is 1-10 mol%. However, in the case where the other structural unit (β) is a structural unit derived from (a-4) acrylonitrile, the ratio of the other structural unit (β) (structural unit derived from (a-4) acrylonitrile) is It is necessary that it is 5 mol% or less with respect to 100 mol% of (A) copolymer. On the other hand, most preferably, it does not contain the structural unit derived from (a-4) acrylonitrile.

The manufacturing method of the said (A) copolymer is not specifically limited, For example, an emulsion polymerization method, suspension polymerization method, and solution polymerization method can be used. Among these, it is preferable to manufacture by emulsion polymerization method.

When manufacturing by emulsion polymerization, each monomer is emulsified in water using surfactant first. Then, as a polymerization initiator, radical polymerization initiators, such as a peroxide catalyst and a redox type catalyst, and molecular weight regulators, such as a mercaptan type compound and a terpene compound, are added as needed, and superposition | polymerization is performed at 0-50 degreeC. Subsequently, after reaching a predetermined polymerization conversion rate, a reaction terminator such as N, N-diethylhydroxylamine is added to stop the polymerization reaction. After the polymerization reaction is stopped, the copolymer emulsion can be obtained by removing the unreacted monomer in the polymerization system by steam distillation or the like. The copolymer copolymer (A) can be isolated by adding the obtained copolymer emulsion to an aqueous electrolyte solution of a predetermined concentration, coagulating the (A) copolymer in the copolymer emulsion (breaking the emulsion), washing with water and drying.

As a coagulation method of the copolymer (A), in addition to the salts formed by adding a copolymer emulsion to the aqueous solution of the electrolyte at a predetermined concentration, when a nonionic surfactant is used as the surfactant, the copolymer is heated above the cloud point of the nonionic surfactant ( A) The method of coagulating a copolymer is mentioned. In addition, when surfactant other than a nonionic surfactant is used, (A) copolymer can also be solidified by adding a nonionic surfactant after superposition | polymerization, and heating above cloud point.

Although the said surfactant is not specifically limited, For example, alkyl sulfate salt, polyoxyethylene alkyl ether sulfate ester salt, alkylbenzene sulfonate, alkyl diphenyl ether disulfonate, alkenyl succinate dipotassium, sodium alkanesulfonate, etc. Anionic surfactants; Cationic surfactants such as alkylamine salts and quaternary ammonium salts; Nonionic surfactants and amphoteric surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene fatty acid ester, polyoxyethylene sorbitan fatty acid ester and fatty acid monoglyceride; And reactive emulsifiers. These surfactant can be used individually or in mixture of 2 or more types.

The copolymer (A) is preferably blended in an amount of 50 to 200 parts by mass with respect to 100 parts by mass of (B) the thermosetting resin, and more preferably in an amount of 70 to 150 parts by mass. When the compounding quantity is in the above range, the adhesiveness of the adhesive layer obtained is improved, and there is an advantage in that peeling during long-term use is unlikely to occur. Moreover, there exists an advantage that the compatibility of (A) copolymer and another component improves, and the heat resistance of the adhesive bond layer obtained improves.

The copolymer (A) preferably has a glass transition temperature (Tg) of -90 to 0 ° C, more preferably -80 to -10 ° C, and particularly preferably -70 to -20 ° C. When the glass transition temperature (Tg) of the (A) copolymer is less than -90 ° C, the heat resistance of the copolymer may be lowered. On the other hand, when it exceeds 0 degreeC, there exists a possibility that the rubber elasticity of a copolymer may be lost. In addition, in this specification, when referring to "glass transition temperature (Tg)", the value measured with the differential scanning calorimeter shall be referred. It is a value when it analyzes on the conditions of the temperature increase rate of 10 degree-C / min using a differential scanning calorimeter (The Seiko Instruments company make, brand name "EXSTAR6000DSC") after heat-drying (A) copolymer specifically ,.

(A) the copolymer has a Mooney viscosity (ML _{1 +4,} 100 ℃) is from 40 to 90 is preferable, more preferably 45 to 85, and particularly preferably from 50 to 80. When the Mooney viscosity of the copolymer (A) is less than 40, the viscosity of the rubber becomes too low, the adhesiveness becomes strong, and there is a fear that the productivity may decrease. On the other hand, when it exceeds 90, there exists a possibility that workability may fall. In addition, in this specification, when it says "Money viscosity", it preheats for 1 minute using ML rotor based on JISK6300 using the Mooney tester (The Alpha Technologies company make, brand name "MOONEY MV 2000E"). It is said that the value measured on the rotor operating time of 4 minutes and temperature 100 degreeC conditions.

On the other hand, it is preferable that the quantity of the alkali metal ion contained in (A) copolymer is 50 ppm or less. More preferably, it is 30 ppm or less, Especially preferably, it is 20 ppm or less. When content of an alkali metal ion exceeds 50 ppm, there exists a possibility that insulation failure may arise. On the other hand, as alkali metal ion, it is preferable that they are sodium ion and potassium ion. That is, it is preferable that the total amount of sodium ion and potassium ion is 50 ppm or less.

Moreover, the adhesive composition of this invention is 5 mol with respect to 100 mol% of all the structural units which the ratio of the structural unit derived from (a-4) acrylonitrile contained in the (A) copolymer comprises the (A) copolymer. It is preferable that it is% or less. More preferably, it is 3 mol% or less, More preferably, it is 2 mol% or less, Especially preferably, it is 1 mol% or less. In addition, the ratio of the structural unit derived from the most preferable acrylonitrile is 0 mol%, ie, it is a case where it is not contained at all.

Here, the conventional adhesive composition contains a copolymer containing a structural unit derived from a predetermined amount or more of acrylonitrile in terms of compatibility with a thermosetting resin, especially an epoxy resin, and contains a structural unit derived from acrylonitrile. As a copolymer to be mentioned, the acrylonitrile butadiene copolymer, the carboxy modified acrylonitrile butadiene copolymer, etc. are used, for example. For example, Patent Document 1 contains an acrylonitrile-butadiene copolymer as a copolymer containing a structural unit derived from acrylonitrile, and the acrylonitrile content of the acrylonitrile-butadiene copolymer is 10 to 50. The adhesive composition which is mol% is disclosed. However, the adhesive layer formed by the adhesive composition was not sufficient in terms of electrical properties (particularly, low dielectric constant and low dielectric loss), and still left room for improvement.

On the other hand, the adhesive composition of this invention has a ratio of the structural unit derived from (a-4) acrylonitrile contained in (A) copolymer with respect to 100 mol% of all the structural units which comprise (A) copolymer. It is preferable to set it as mol% or less, and in this case, the fall (deterioration) of the electrical characteristics (especially low dielectric constant and low dielectric loss) resulting from the structural unit derived from acrylonitrile can be avoided. In addition, by including the structural unit (a-2) in the (A) copolymer, even if the ratio of the structural unit (a-4) is 5 mol% or less, good compatibility with the epoxy resin can be improved. The adhesive layer formed by the adhesive composition of the present invention containing such a copolymer (A) exhibits excellent electrical properties (particularly low dielectric constant and low dielectric loss) while maintaining good compatibility with thermosetting resins, especially epoxy resins. There is an advantage to exercise.

[1-2] (B) Thermosetting Resin:

Although the (B) thermosetting resin contained in the adhesive composition of this invention is not specifically limited, An epoxy resin, a phenol resin, etc. can be used. Among these, an epoxy resin is preferable. As an epoxy resin, the thing of the structure which has two or more epoxy groups in a molecule is preferable. For example, bisphenol-A epoxy resin, bisphenol F-type epoxy resin, bisphenol S-type epoxy resin, naphthol novolak-type epoxy resin, biphenyl novolak-type epoxy resin, phenol novolak-type epoxy resin, cresol novolak-type epoxy resin Etc. can be mentioned. Among these, bisphenol-type epoxy resins are preferable. In addition, the said (B) thermosetting resin can be used individually or in combination of 2 or more types. In addition, in order to impart flame retardancy, a halogenated epoxy resin such as a brominated epoxy resin may be added to the epoxy resin.

[1-3] (C) Curing Agent:

Although the (C) hardening | curing agent contained in the adhesive composition of this invention is not specifically limited, For example, amines, such as diaminodiphenylmethane, diaminodiphenyl sulfide, diaminodiphenyl sulfone, diamino benzophenone, and polyamide Imidazole derivatives such as resin, 2-alkyl-4-methylimidazole, 2-phenyl-4-alkylimidazole, acid anhydrides such as phthalic anhydride and trimellitic anhydride, phenol resins, polysulfide resins , Polyvinylphenols, dicyandiamide, dibasic dihydrazide, organic boron, organic phosphine, guanidines and salts thereof. In addition, these can be used individually or in combination of 2 or more types. Moreover, a hardening accelerator can also be used together with (C) hardening agent for the purpose of promoting hardening reaction. Here, in this specification, a "hardening agent" is a concept including forming a crosslinked structure by itself, and promoting the crosslinking reaction without forming the crosslinked structure by itself. The "curing accelerator" means to increase the crosslinking reaction action of the curing agent.

It is preferable that it is 0.1-20 mass parts with respect to 100 mass parts of (B) thermosetting resins, and, as for the compounding quantity of (C) hardening | curing agent, it is more preferable that it is 0.5-10 mass parts. If the compounding quantity of (C) hardening | curing agent is less than 0.1 mass part, there exists a possibility that it may become hardening. On the other hand, when it exceeds 20 mass parts, there exists a possibility that storage stability may fall.

[1-4] Other additives:

The adhesive composition of the present invention is, in addition to the (A) copolymer, the (B) thermosetting resin, and the (C) curing agent, an organic solvent, adhesion aid, leveling agent, inorganic filler, polymer additive, reactive diluent, wettability improving agent, and interface as necessary. Active agents, plasticizers, antioxidants, antistatic agents, mold inhibitors, humidity regulators, flame retardants, and other additives may be included, and these additives may be used in amounts that do not impair the effects of the present invention.

An organic solvent can be added in order to improve the handleability of an adhesive composition, or to adjust a viscosity and storage stability. Although such an organic solvent is not specifically limited, For example, ethylene glycol monoalkyl ether acetates, such as ethylene glycol monomethyl ether acetate and ethylene glycol monoethyl ether acetate; Propylene glycol monoalkyl ethers such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, and propylene glycol monobutyl ether; Propylene glycol dialkyl ethers such as propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dipropyl ether, and propylene glycol dibutyl ether; Propylene glycol monoalkyl ether acetates such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, and propylene glycol monobutyl ether acetate;

Cellosolves such as ethyl cellosolve and butyl cellosolve; Carbitols such as butyl carbitol; Lactic acid esters such as methyl lactate, ethyl lactate, n-propyl lactate, and isopropyl lactate; Aliphatic carboxylic acid esters, such as ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, n-amyl acetate, isoamyl acetate, isopropyl propionate, n-butyl propionate, and isobutyl propionate Ryu; Other esters such as methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, methyl pyruvate and ethyl pyruvate; Aromatic hydrocarbons such as toluene and xylene; Ketones such as 2-butanone (methylethyl ketone), 2-heptanone, 3-heptanone, 4-heptanone, and cyclohexanone; Amides such as N-dimethylformamide, N-methylacetamide, N, N-dimethylacetamide and N-methylpyrrolidone; Lactones, such as (gamma) -butyrolactone, are mentioned. Among these, aromatic hydrocarbons and ketones are preferable. These organic solvents can be used individually or in mixture of 2 or more types.

[2] Preparation of Adhesive Composition-Containing Varnishes:

The adhesive composition containing varnish containing the adhesive composition of this invention can be manufactured as follows, for example. First, (B) thermosetting resin and (A) copolymer are thrown in the said organic solvent, and it melt | dissolves completely using a stirrer. Then, the said adhesive composition containing varnish can be obtained by adding (C) hardening | curing agent, making it a uniform solution, and making solid content concentration into about 40 (35-45)%.

[3] substrates for flexible printed wiring boards:

The board | substrate for flexible printed wiring boards of this invention is formed with the insulating film layer, the circuit board, and the adhesive composition of this invention mentioned above, and is arrange | positioned between the said insulating film layer and the said circuit board, and it has replaced the said insulating film layer and the said circuit board. It is provided with the adhesive bond layer. Thus, since the adhesive bond layer formed with the adhesive composition of this invention is provided, there exists an advantage that thickness reduction (lightening) and high density of the board | substrate for flexible printed wiring boards can be achieved.

The board | substrate for flexible printed wiring boards of this invention can apply the adhesive composition containing varnish mentioned above to an insulating film layer, for example, can arrange | position and dry a circuit board on this coating film. The circuit board can be formed of, for example, copper foil, aluminum foil, silver foil, gold foil, or the like.

As a method of coating the said adhesive composition containing varnish to an insulating film layer, coating methods, such as an immersion method, the spraying method, the bar coating method, the roll coating method, or the spin coating method, can be used, for example. Moreover, as an insulating film layer, a polyimide film, a polyester film, a polyethylene naphthalate film, a polyetherimide film, etc. are mentioned, for example.

In addition, the said board for flexible printed wiring boards can also adhere | attach 2 or more, and can also be set as the board | substrate for flexible printed wiring boards of a multilayer form.

<Example>

EMBODIMENT OF THE INVENTION Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples. In addition, "part" and "%" in an Example and a comparative example are a mass reference | standard unless there is particular notice.

(A-1) copolymer-(A-11) copolymer were synthesize | combined with the following method, and were used for each Example and the comparative example.

Synthesis Example 1

[Synthesis of (A-1) Copolymer]

40 parts (61.6 mol%) of butadiene and 60 parts (38.4 mol%) of 2-hydroxyethyl methacrylate were put into the autoclave as the aqueous solution which melt | dissolved 5 parts of dodecylbenzene sulfonates, and a raw material monomer. Subsequently, 0.2 part of t-dodecyl mercaptan and a redox catalyst were put into this autoclave as a molecular weight modifier, and it temperature-controlled at 10 degreeC. Then, 0.01 part of paramentane hydroxide was added as a polymerization initiator, and emulsion polymerization was performed to 75% of a polymerization conversion rate. Subsequently, N, N-diethylhydroxylamine was added as a reaction terminator, and the copolymer emulsion was obtained. Water vapor was blown in the obtained copolymer emulsion, and the unreacted raw material monomer (butadiene, 2-hydroxyethyl methacrylate) was removed. The solution which removed the raw material monomer was added to 5% calcium chloride aqueous solution, and the copolymer was deposited. The precipitated copolymer was washed with distilled water and dried with a blow dryer set at 80 ° C to isolate the (A-1) copolymer.

On the other hand, it was 70 when the Mooney viscosity (ML _{1 + 4 (} 100 _degreeC )) was measured about the (A-1) copolymer using the Mooney tester (made by Alpha Technology Corporation). Furthermore, as a result of analyzing the content of alkali metal ions contained in the copolymer (A-1) using an atomic absorption photometer (manufactured by Hitachi Hi-Tech Co., Ltd.), Na; 20 ppm, K; 10 ppm (total content of alkali metal ions; 30 ppm). The glass transition temperature (Tg) of the copolymer (A-1) was -12 ° C. The content rate of the (a-1) structural unit was 65.0 mol% and the content rate of the (a-2) structural unit was 35.0 mol% with respect to 100 mol% of all the structural units of the (A-1) copolymer. In addition, the content rate of the structural unit derived from acrylonitrile is 0 mol%.

Synthesis Example 2

[Synthesis of (A-2) Copolymer]

Aqueous solution dissolving 10 parts of polyoxyethylene alkyl ether, using 75 parts (89.8 mol%) of butadiene, 25 parts (10.2 mol%) of 2-hydroxybutyl methacrylate, and 2 parts of terpinolenes as a molecular weight modifier as a raw material monomer. A copolymer emulsion was obtained in the same manner as in Synthesis example 1 except for the above. Thereafter, water vapor was blown into the obtained copolymer emulsion to remove unreacted raw material monomers (butadiene and 2-hydroxybutyl methacrylate). The copolymer which precipitated the copolymer by adding the solution remove | excluding the raw material monomer in 5% aqueous solution of ammonium sulfate (blur lowering agent), and blowing in water vapor further. Thereafter, the precipitated copolymer was washed with distilled water and dried with a blow dryer set at 80 ° C to isolate the copolymer (A-2).

On the other hand, it was 65 when the Mooney viscosity (ML _{1 + 4} (100 _degreeC )) was measured about the (A-2) copolymer using the Mooney tester (made by Alpha Technology Corporation). Furthermore, as a result of analyzing the content of alkali metal ions contained in the (A-2) copolymer using an atomic absorption photometer (manufactured by Hitachi Hi-Tech Co., Ltd.), Na; 15 ppm, K; 8 ppm (total content of alkali metal ions; 23 ppm). The glass transition temperature (Tg) of the copolymer (A-2) was -48 ° C. The content rate of the (a-1) structural unit was 90.0 mol% and the content rate of the (a-2) structural unit was 10.0 mol% with respect to 100 mol% of all the structural units of the (A-2) copolymer. In addition, the content rate of the structural unit derived from acrylonitrile is 0 mol%.

Synthesis Example 3

[Synthesis of (A-3) Copolymer]

A copolymer (A-3) was synthesized and isolated in the same manner as in Synthesis example 2, except that 75 parts (74.6 mol%) of butadiene and 25 parts (25.4 mol%) of acrylonitrile were used as the raw material monomers.

It was 72 when the Mooney viscosity (ML _{1 + 4} (100 _degreeC )) was measured about the (A-3) copolymer using the Mooney tester (made by Alpha Technology Corporation). Furthermore, as a result of analyzing the content of alkali metal ions contained in the (A-3) copolymer using an atomic absorption photometer (manufactured by Hitachi Hi-Tech Co., Ltd.), Na; 17 ppm, K; 7 ppm (total content of alkali metal ions; 24 ppm). The glass transition temperature (Tg) of the copolymer (A-3) was -42 ° C. The content rate of the (a-1) structural unit was 75.5 mol% and the content rate of the (a-2) structural unit was 0 mol% with respect to 100 mol% of all the structural units of the (A-3) copolymer. In addition, the content rate of the structural unit derived from acrylonitrile is 24.5 mol%.

Synthesis Example 4

[Synthesis of (A-4) Copolymer]

As an aqueous solution in which 10 parts of polyoxyethylene alkyl ethers were dissolved, as a raw material monomer, 72 parts (86.1 mol%) of butadiene, 25 parts (10.2 mol%) of 2-hydroxybutyl methacrylate, and 3 parts (3.7 mol%) of acrylonitrile A copolymer emulsion was obtained in the same manner as in Synthesis example 1 except that 2 parts of terpinolene was used as the molecular weight regulator. Thereafter, water vapor was blown into the obtained copolymer emulsion to remove unreacted raw material monomers (butadiene and 2-hydroxybutyl methacrylate). The copolymer which precipitated the copolymer by adding the solution remove | excluding the raw material monomer in 5% aqueous solution of ammonium sulfate (blur lowering agent), and blowing in water vapor further. Thereafter, the precipitated copolymer was washed with distilled water and dried in a blow dryer set at 80 ° C to isolate the copolymer (A-4).

It was 70 when the Mooney viscosity (ML _{1 + 4} (100 _degreeC )) was measured about the (A-4) copolymer using the Mooney tester (made by Alpha Technology). Furthermore, as a result of analyzing the content of the alkali metal ion contained in the (A-4) copolymer using an atomic absorption photometer (manufactured by Hitachi Hi-Tech Co., Ltd.), Na; 16 ppm, K; 8 ppm (total content of alkali metal ions; 24 ppm). The glass transition temperature (Tg) of the (A-4) copolymer was -44 ° C. The content rate of the (a-1) structural unit was 76.5 mol% and the content rate of the (a-2) structural unit was 10.0 mol% with respect to 100 mol% of all the structural units of the (A-4) copolymer. In addition, the content rate of the structural unit derived from acrylonitrile is 3.5 mol%.

Synthesis Example 5

[Synthesis of (A-5) Copolymer]

Aqueous solution dissolving 10 parts of polyoxyethylene alkyl ether, using 30 parts of butadiene (55.6 mol%), 70 parts of 2-hydroxybutyl methacrylate (45.4 mol%) as a raw material monomer, and 2 parts of terpinolene as a molecular weight regulator. A copolymer emulsion was obtained in the same manner as in Synthesis example 1 except for the above. Thereafter, water vapor was blown into the obtained copolymer emulsion to remove unreacted raw material monomers (butadiene and 2-hydroxybutyl methacrylate). The copolymer which precipitated the copolymer by adding the solution remove | excluding the raw material monomer in 5% aqueous solution of ammonium sulfate (blur lowering agent), and blowing in water vapor further. Thereafter, the precipitated copolymer was washed with distilled water and dried in a blow dryer set at 80 ° C to isolate the copolymer (A-5).

It was 69 when the Mooney viscosity (ML _{1 + 4} (100 _degreeC )) was measured about the (A-5) copolymer using the Mooney tester (made by Alpha Technology). Furthermore, as a result of analyzing the content of alkali metal ions contained in the (A-5) copolymer using an atomic absorption photometer (manufactured by Hitachi Hi-Tech Co., Ltd.), Na; 15 ppm, K; 5 ppm (total content of alkali metal ions; 20 ppm). The glass transition temperature (Tg) of the (A-5) copolymer was -3 ° C. The content rate of the (a-1) structural unit was 56.5 mol% and the content rate of the (a-2) structural unit was 43.5 mol% with respect to 100 mol% of all the structural units of the (A-5) copolymer. In addition, the content rate of the structural unit derived from acrylonitrile is 0 mol%.

Synthesis Example 6

[Synthesis of (A-6) Copolymer]

55 parts (74.4 mol%) of butadiene, 25 parts (11.6 mol%) of 2-hydroxybutyl methacrylate, and 20 parts (14.0 mol%) of styrene were used as the aqueous solution which melt | dissolved 5 parts of dodecylbenzene sulfonates, and a raw material monomer. Placed in autoclave. Subsequently, 0.2 part of t-dodecyl mercaptan and a redox catalyst were put into this autoclave as a molecular weight modifier, and it temperature-controlled at 10 degreeC. Then, 0.01 part of paramentane hydroxide was added as a polymerization initiator, and emulsion polymerization was performed to 75% of a polymerization conversion rate. Subsequently, N, N-diethylhydroxylamine was added as a reaction terminator, and the copolymer emulsion was obtained. Water vapor was blown into the obtained copolymer emulsion to remove unreacted raw material monomers (butadiene, 2-hydroxybutyl methacrylate, and styrene). The solution which removed the raw material monomer was added to 5% calcium chloride aqueous solution, and the copolymer was deposited. The copolymer (A-6) was isolated by washing the precipitated copolymer with distilled water and drying with a blow dryer set at 80 ° C.

On the other hand, it was 60 when the Mooney viscosity (ML _{1 + 4} (100 _degreeC )) was measured about the (A-6) copolymer using the Mooney tester (made by Alpha Technology). Furthermore, as a result of analyzing the content of the alkali metal ion contained in the (A-6) copolymer using an atomic absorption photometer (manufactured by Hitachi Hi-Tech Co., Ltd.), Na; 22 ppm, K; 12 ppm (total content of alkali metal ions: 34 ppm). The glass transition temperature (Tg) of the copolymer (A-6) was -23 ° C. The content rate of the structural unit (a-1) is 73.5 mol% based on 100 mol% of the total structural units of the (A-6) copolymer, and the content rate of the structural unit (a-2) is 12.0 mol%, (a -3) The content rate of the structural unit ((a-3-2) structural unit) was 14.5 mol%. In addition, the content rate of the structural unit derived from (a-4) acrylonitrile is 0 mol%.

Synthesis Example 7

[Synthesis of (A-7) Copolymer]

As an aqueous solution in which 10 parts of polyoxyethylene alkyl ethers were dissolved, as a raw material monomer, 75 parts (87.4 mol%) of butadiene, 23 parts (11.1 mol%) of 2-hydroxyethyl methacrylate, and 2 parts (1.5 mol%) of methacrylic acid ) And a copolymer emulsion was obtained in the same manner as in Synthesis example 1 except that 2 parts of terpinolene was used as the molecular weight regulator. Thereafter, water vapor was blown into the obtained copolymer emulsion to remove unreacted raw material monomers (butadiene, 2-hydroxyethyl methacrylate, and methacrylic acid). The copolymer which precipitated the copolymer by adding the solution remove | excluding the raw material monomer in 5% aqueous solution of ammonium sulfate (blur lowering agent), and blowing in water vapor further. Thereafter, the precipitated copolymer was washed with distilled water and dried with a blow dryer set at 90 ° C to isolate the (A-7) copolymer.

On the other hand, it was 72 when the Mooney viscosity (ML _{1 + 4} (100 _degreeC )) was measured about the (A-7) copolymer using the Mooney tester (made by Alpha Technology Corporation). Furthermore, as a result of analyzing the content of alkali metal ions contained in the (A-7) copolymer using an atomic absorption photometer (manufactured by Hitachi Hi-Tech Co., Ltd.), Na; 11 ppm, K; 7 ppm (total content of alkali metal ions; 18 ppm). The glass transition temperature (Tg) of the copolymer (A-7) was -47 ° C. The content rate of the (a-1) structural unit is 87.4 mol% with respect to 100 mol% of the total structural units of the (A-7) copolymer, and the content rate of the (a-2) structural unit is 10.8 mol%, (a -3) The content rate of the structural unit ((a-3-2) structural unit) was 1.8 mol%. In addition, the content rate of the structural unit derived from (a-4) acrylonitrile is 0 mol%.

Synthesis Example 8

[Synthesis of (A-8) Copolymer]

As a raw material monomer, 50 parts (70.2 mol%) of butadiene, 30 parts (14.4 mol%) of 2-hydroxybutyl methacrylate, 15 parts (10.9 mol%) of styrene, 5 parts (4.4 mol%) of methacrylic acid, And the copolymer emulsion was obtained like Example 2 except having used terpinolene 2 parts as a molecular weight regulator. Thereafter, water vapor was blown into the obtained copolymer emulsion to remove unreacted raw material monomers (butadiene, 2-hydroxybutyl methacrylate, styrene, and methacrylic acid). The copolymer which precipitated the copolymer by adding the solution remove | excluding the raw material monomer in 5% aqueous solution of ammonium sulfate (blur lowering agent), and blowing in water vapor further. Thereafter, the precipitated copolymer was washed with distilled water and dried with a blow dryer set at 90 ° C to isolate the (A-8) copolymer.

On the other hand, it was 75 when the Mooney viscosity (ML _{1 + 4} (100 _degreeC )) was measured about the (A-8) copolymer using the Mooney tester (made by Alpha Technology). Furthermore, as a result of analyzing the content of alkali metal ions contained in the (A-8) copolymer using an atomic absorption photometer (manufactured by Hitachi Hi-Tech Co., Ltd.), Na; 12 ppm, K; 4 ppm (total content of alkali metal ions; 16 ppm). The glass transition temperature (Tg) of the (A-8) copolymer was -14 ° C. The content rate of the (a-1) structural unit is 70.0 mol% with respect to 100 mol% of the total structural units of the (A-8) copolymer, and the content rate of the (a-2) structural unit is 14.2 mol%, (a -3-1) The content rate of structural units was 10.2 mol%, and the content rate of (a-3-2) structural units was 5.6 mol%. In addition, the content rate of the structural unit derived from (a-4) acrylonitrile is 0 mol%.

Synthesis Example 9

[Synthesis of (A-9) Copolymer]

Except for using 65 parts (67.2 mol%) of butadiene, 25 parts (26.3 mol%) of acrylonitrile, and 10 parts (6.5 mol%) of methacrylic acid as raw material monomers (A-9). ) Copolymers were synthesized and isolated.

On the other hand, it was 72 when the Mooney viscosity (ML _{1 + 4} (100 _degreeC )) was measured about the (A-9) copolymer using the Mooney tester (made by Alpha Technology). Furthermore, as a result of analyzing the content of alkali metal ions contained in the (A-9) copolymer using an atomic absorption photometer (manufactured by Hitachi Hi-Tech Co., Ltd.), Na; 20 ppm, K: 10 ppm (total content of alkali metal ions; 30 ppm). The glass transition temperature (Tg) of the (A-9) copolymer was -25 ° C. The content rate of the (a-1) structural unit is 67.0 mol% based on 100 mol% of the total structural units of the (A-9) copolymer, and the content rate of the structural unit (a-2) is 0 mol%, (a -3) The content rate of the structural unit ((a-3-2) structural unit) was 6.8 mol%. In addition, the content rate of the structural unit derived from (a-4) acrylonitrile is 26.2 mol%.

Synthesis Example 10

[Synthesis of (A-10) Copolymer]

A (A-10) copolymer was synthesized and isolated in the same manner as in Synthesis Example 2, except that 75 parts (74.6 mol%) of butadiene and 25 parts (25.4 mol%) of acrylonitrile were used as the raw material monomers.

On the other hand, it was 72 when the Mooney viscosity (ML _{1 + 4} (100 _degreeC )) was measured about the (A-10) copolymer using the Mooney tester (made by Alpha Technology). Furthermore, as a result of analyzing the content of alkali metal ions contained in the (A-10) copolymer using an atomic absorption photometer (manufactured by Hitachi Hi-Tech Co., Ltd.), Na; 17 ppm, K; 7 ppm (total content of alkali metal ions; 24 ppm). The glass transition temperature (Tg) of the (A-10) copolymer was -42 ° C. The content rate of the structural unit (a-1) is 74.2 mol% based on 100 mol% of the total structural units of the (A-10) copolymer, and the content rate of the structural unit (a-2) is 0 mol%, (a -3) The content rate of the structural unit was 0 mol%. In addition, the content rate of the structural unit derived from (a-4) acrylonitrile is 25.8 mol%.

Synthesis Example 11

[Synthesis of (A-11) Copolymer]

As an aqueous solution in which 10 parts of polyoxyethylene alkyl ethers were dissolved, as a raw material monomer, 70 parts of butadiene (84.5 mol%), 25 parts of 2-hydroxybutyl methacrylate (10.3 mol%) and 2 parts of methacrylic acid (1.5 mol%) A copolymer emulsion was obtained in the same manner as in Synthesis Example 1 except that 3 parts of acrylonitrile (3.7 mol%) and 2 parts of terpinolene were used as the molecular weight regulator. Thereafter, water vapor was blown into the obtained copolymer emulsion to remove unreacted raw material monomers (butadiene and 2-hydroxybutyl methacrylate). The copolymer which precipitated the copolymer by adding the solution remove | excluding the raw material monomer in 5% aqueous solution of ammonium sulfate (blur lowering agent), and blowing in water vapor further. Thereafter, the precipitated copolymer was washed with distilled water and dried with a blow dryer set at 80 ° C to isolate the copolymer (A-11).

On the other hand, it was 70 when the Mooney viscosity (ML _{1 + 4} (100 _degreeC )) was measured about the (A-11) copolymer using the Mooney tester (made by Alpha Technology). Furthermore, as a result of analyzing the content of alkali metal ions contained in the (A-11) copolymer using an atomic absorption photometer (manufactured by Hitachi Hi-Tech Co., Ltd.), Na; 14 ppm, K; 4 ppm (total content of alkali metal ions; 18 ppm). The glass transition temperature (Tg) of the (A-11) copolymer was -41 ° C. The content rate of the structural unit (a-1) is 85.0 mol% based on 100 mol% of the total structural units of the (A-11) copolymer, and the content rate of the structural unit (a-2) is 10.2 mol%, (a -3) The content rate of the structural unit ((a-3-2) structural unit) was 1.5 mol%. In addition, the content rate of the structural unit derived from (a-4) acrylonitrile is 3.3 mol%.

In addition, the structural unit ((a-4) derived from the (a-1) structural unit, (a-2) structural unit, and acrylonitrile contained in the (A-1) copolymer-(A-11) copolymer The content (ratio) (mol%) of the structural unit) is shown in Tables 1 and 2.

(Example 1)

70 parts of (A-1) copolymers obtained in Synthesis Example 1 as the (A) copolymer, and (B) an epoxy resin as the thermosetting resin (trade name "Epicoat 828", manufactured by Japan Epoxy Resin Co., Ltd., "B-1" in the table). 50 parts of (B) 50 parts of the epoxy resin (trade name "Epicoat 1001", manufactured by Japan Epoxy Resin Co., Ltd. and represented by "B-2" in the table) as the thermosetting resin, methyl ethyl ketone (organic solvent) It poured into 263 parts and melt | dissolved completely by the stirrer "MAZERA Z" (made by Tokyo Rika Kikai Co., Ltd.). Thereafter, 5 parts of diaminodiphenylmethane (trade name "Smicure M", manufactured by Sumitomo Chemical Industries, "C-1" in the table) were added as a curing agent (C). It was. In this manner, an adhesive composition-containing varnish (adhesive composition) having a solid content concentration of about 40% was obtained. The obtained adhesive composition containing varnish evaluated each following evaluation by each method.

[Compatibility]

The adhesive composition-containing varnish was placed in a transparent glass bottle, and the haze of the solution and the presence or absence of precipitates were visually confirmed. Judgment made the case of a uniform solution "good", the case that a solution was turbid and a deposit was confirmed as "defect".

[Electrical characteristics]

The said adhesive composition containing varnish was apply | coated to the SUS board on which the surface was mirror-finished, and it heated in 90 degreeC x 15 minutes in the convection oven. Then, it heated further at 170 degreeC for 1 hour, and formed the adhesive layer of 20 micrometers thickness on the SUS board. An aluminum electrode was formed on this adhesive layer, and the dielectric constant and dielectric loss were measured under the condition of 1 MHz by a dielectric constant / dielectric loss measuring instrument (HCR Packer: LCR meter HP4248).

[Adhesiveness]

The adhesive composition-containing varnish was applied to a copper plate having a thickness of 1 mm, and heated in a convection oven at 90 ° C. for 15 minutes. Then, it heated further at 170 degreeC for 1 hour, and formed the adhesive layer of 20 micrometers thickness on the SUS board. After superimposing a polyimide film (Ube Kosan Co., Ltd. product, Yupyrex 75S) on this adhesive bond layer, it crimped | bonded and bonded on 130 degreeC, 0.5 MPa, and 1 minute conditions using the press machine (manufactured by Kansai Roll Co., Ltd.). Thereafter, the adhesive layer was cured by heating at 170 ° C. for 1 hour in a clean oven. The sample plate (copper plate-adhesive layer-polyimide film) obtained in this way was formed with the cutter by the cutter at the polyimide film side, and the 90 degree peeling test was done. Specifically, 90 degree peeling strength (kg / cm) was measured using the adhesion tester (made by Yamamoto Plating Test Co., Ltd.) based on JIS C6481 (copper laminated board test method for printed wiring boards). The measured peel strength was used as an index of the adhesive judgment.

The evaluation result of each said evaluation in a present Example was favorable compatibility, the dielectric constant was 3.4, the dielectric loss was 0.03, and peeling strength was 1.1 kg / cm as electrical characteristics.

(Examples 2 to 4, Comparative Example 1)

An adhesive composition (adhesive composition-containing varnish) was obtained in the same manner as in the case of Example 1 described above except that the formulation was shown in Table 2. Each evaluation result of the obtained adhesive composition is shown in Table 3.

(Example 5)

70 parts of (A-5) copolymers obtained by the synthesis example 5 as (A) copolymer, and (B) epoxy resin as a thermosetting resin (brand name "Epicoat 828", the Japan epoxy resin company make, "B-1" in a table | surface) 50 parts of (B) 50 parts of epoxy resins (trade name "Epicoat 1001", manufactured by Japan Epoxy Resin Co., Ltd., represented by "B-2" in the table) as thermosetting resins, and 263 parts of toluene (organic solvent). It was put in and completely dissolved in a stirrer "MAZERA Z" (manufactured by Tokyo Rika Kikai Co., Ltd.). Thereafter, 5 parts of diaminodiphenylmethane (trade name "Smicure M", manufactured by Sumitomo Chemical Industries, "C-1" in the table) were added as a curing agent (C). It was. In this manner, an adhesive composition-containing varnish (adhesive composition) having a solid content concentration of about 40% was obtained. The compatibility, electrical property, and adhesiveness which were mentioned above were evaluated about the obtained adhesive composition containing varnish, respectively, and the following glass transition temperature was measured.

[Glass transition temperature]

Viscoelasticity was measured using TMA / SS6100 (manufactured by Seiko Instruments Co., Ltd.), and the glass transition temperature (Tg) of the cured product was determined from the behavior of tanδ. Test conditions were 50 micrometers in thickness / 3 mm in width, and the temperature increase rate was 5 degreeC / min.

The evaluation result of each said evaluation in a present Example was favorable compatibility, the dielectric constant was 3.3, the dielectric loss was 0.02, the peeling strength was 1.2 kg / cm, and the glass transition temperature (Tg) was 140 degreeC as electrical characteristics.

(Examples 6 to 11, Comparative Examples 2 and 3)

An adhesive composition (adhesive composition-containing varnish) was obtained in the same manner as in the case of Example 5 described above except that the formulation was shown in Table 4. Each evaluation result of the obtained adhesive composition is shown in Table 4.

As shown in Tables 3 and 4, when the adhesive compositions of Examples 1 to 8 are used, they have excellent electrical properties (particularly, permittivity and It is clear that the adhesive layer (low dielectric loss) can be formed.

The adhesive composition of the present invention can form an adhesive layer having excellent electrical properties (particularly low dielectric constant and low dielectric loss) while maintaining sufficient adhesive performance, and the adhesive composition of the present invention is particularly useful for communication of electronic devices, mobile phones, and the like. It can use suitably as an adhesive bond layer, such as a board | substrate for flexible printed wiring boards of an apparatus.

Claims (10)

(A) (a-1) Copolymer containing structural unit derived from monomer which has two or more ethylenically polymerizable unsaturated groups, and (a-2) structural unit derived from monomer which has alcoholic hydroxyl group, (B) a thermosetting resin, and (C) curing agent Adhesive composition containing. The ratio of the structural unit (a-1) is 50 to 95 mol%, based on 100 mol% of the total structural units constituting the copolymer (A), The adhesive composition of the said (a-2) structural unit is 5-50 mol% with respect to 100 mol% of all the structural units which comprise the said (A) copolymer. The structural unit according to claim 1, wherein the (A) copolymer further comprises at least one member selected from the group consisting of (a-3) styrene, styrene derivatives, (meth) acrylic acid, and (meth) acrylic acid derivatives. Adhesive composition comprising a. The ratio of the structural unit (a-1) is 50 to 90 mol%, based on 100 mol% of the total structural units constituting the copolymer (A), The proportion of the structural unit (a-2) is 5 to 45 mol% with respect to 100 mol% of all the structural units constituting the (A) copolymer, The adhesive composition of the said (a-3) structural unit is 1-25 mol% with respect to 100 mol% of all the structural units which comprise the said (A) copolymer. The adhesive composition according to claim 1, wherein the structural unit (a-1) is a structural unit derived from a diene monomer. The adhesive composition according to claim 1, wherein the structural unit (a-2) is a structural unit derived from hydroxyalkyl (meth) acrylate. The molar ratio of the structural unit derived from (a-4) acrylonitrile contained in the said (A) copolymer is 5 mol with respect to 100 mol% of all the structural units which comprise the said (A) copolymer. Adhesive composition which is% or less. The adhesive composition of Claim 1 containing an epoxy resin as said (B) thermosetting resin. The adhesive composition of Claim 1 whose content of the alkali metal ion contained in the said (A) copolymer is 50 ppm or less. Insulating film layer, A circuit board, and The board | substrate for flexible printed wiring boards formed with the adhesive composition of Claim 1, Comprising: The adhesive layer which is arrange | positioned between the said insulating film layer and the said circuit board, and adhere | attaches the said insulating film layer and the said circuit board is provided.