KR101582492B1 - Adhesive composition and coverlay film using the same - Google Patents

Abstract

The present invention relates to an adhesive composition and a coverlay film to which the adhesive composition is applied.

The adhesive composition of the present invention contains an optimal ratio of a non-halogen epoxy resin, an acrylic rubber containing a carboxyl group, a multifunctional curing agent for epoxy resins, a phosphorus-based flame retardant, and a fluorine-based compound and contains no halogen, It is free from gas generation. When applied to an electrically conductive substrate, it has improved low dielectric constant and migration resistance, and can be applied as a coverlay film. When applied to an electronic product, it can improve electrical reliability.

Adhesive, coverlay, my migration

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an adhesive composition,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive composition and a coverlay film using the same, and more particularly, to an adhesive composition containing a halogen-free epoxy resin, an acrylic rubber containing a carboxyl group, a multifunctional curing agent for epoxy resins, a phosphorus- And a coverlay film using the same.

Recently, rapid development of integration degree of semiconductor integrated circuits in electronic industry and development of surface mounting technology for directly mounting small-sized chip components and miniaturization of electronic equipment have made it necessary to facilitate the embedding in a more complicated and narrow space And a flexible circuit board is being developed in response to this demand.

Particularly, in the case of FPCB (FLEXIBLE PRINTED CIRCUIT BOARD), which is highly usable, the use of cellular phones, DVDs, digital cameras, PDPs and the like is rapidly increasing due to technological advancement, It is true.

In general, a flexible circuit board used for assembling electronic equipment is formed by forming a circuit pattern on a laminated base material film composed of an electrically insulating base material film and a metal foil with an adhesive layer interposed therebetween, and removing a release base material for temporary protection, Another insulating film obtained from a ray film is further laminated on the above.

At this time, adhesives used for electronic materials such as semiconductor sealing materials or epoxy-based flexible circuit boards generally exhibit excellent flame retardancy by blending an epoxy resin containing bromine and phenoxy resin. However, when a halogen-containing compound such as bromine is burned, harmful gas such as a dioxin compound may be generated. Therefore, non-halogenation of a material used in an adhesive has been studied recently.

In recent years, miniaturization of electronic products has led to miniaturization of the electronic and electrical fields such as semiconductors and flexible circuit boards. As a result, adhesives used for substrates and substrate sheets for the electronic and electronic parts have excellent electrical properties, And excellent migration is required.

Adhesives used in a substrate film for a flexible circuit board that satisfy the above requirements include various combinations of thermosetting resins, thermoplastic resins and fluorine-based compounds or elastomers. The adhesive compositions proposed so far include a combination of an epoxy resin and a nitrile butadiene rubber (referred to as NBR), a combination of an epoxy resin and a polyester, a combination of an epoxy resin and an acrylic resin, and an epoxy resin / The NBR adhesive composition is most widely used because it has excellent bonding strength as compared with an epoxy resin / acrylic resin adhesive composition.

As the flame retardant containing no halogen, a phosphorus flame retardant and an inorganic flame retardant are widely used.

However, conventional adhesives still have insufficient low permittivity and excellent migration resistance in order to minimize electrical interference between fine patterns.

Thus, the present inventors have made efforts to produce an adhesive for a coverlay film excellent in low dielectric constant and migration resistance without containing a halogen, and as a result, it has been found that an epoxy resin, an acrylic rubber containing a carboxyl group, a multifunctional curing agent for epoxy resins, The present inventors have completed the present invention by confirming that the low dielectric constant and migration resistance of the coverlay film prepared by preparing the adhesive composition containing the fluorine-based compound in an optimum ratio and applying it to the base film and then laminating the release base material are improved.

An object of the present invention is to provide an adhesive composition containing a halogen-free epoxy resin, an acrylic rubber containing a carboxyl group, a multifunctional curing agent for epoxy resin, a phosphorus-based flame retardant and a fluorine-based compound in an optimum ratio.

Another object of the present invention is to provide a coverlay film excellent in migration resistance while securing a low dielectric constant.

In order to achieve the above object, the present invention relates to a photosensitive resin composition comprising 50 to 80 parts by weight of a carboxyl group-containing acrylic rubber, 15 to 20 parts by weight of a multifunctional curing agent for epoxy resin, 20 to 100 parts by weight of a phosphorus- And 5 to 20 parts by weight of a fluorine-based compound, wherein the adhesive composition comprises an ethyl isocyanate compound, 2-phenylimidazole, 2-phenyl-4-methylimidazole, - 1 to 5 parts by weight of a curing accelerator selected from the group consisting of hydroxymethylimidazole and triphenylphosphine.

At this time, the viscosity of the adhesive composition is preferably 200 to 1,000 cps.

Further, the present invention provides a coverlay film having a dielectric constant of 1.0 to 2.5, wherein the adhesive composition is applied onto a base film to form an adhesive layer, and a release substrate is laminated on the adhesive layer.

The adhesive composition of the present invention does not contain halogens and does not generate harmful gas to human body during combustion and contains an optimal content of a specific fluorine-containing compound and a multifunctional curing agent for epoxy resin, and when applied to an electrically insulating substrate, It is possible to provide a coverlay film having excellent migration characteristics, thereby improving electrical reliability when applied to electronic products.

The present invention relates to a resin composition comprising 50 to 80 parts by weight of a carboxyl group-containing acrylic rubber, 15 to 20 parts by weight of a multifunctional curing agent for epoxy resin, 20 to 100 parts by weight of a phosphorus-based flame retardant, and 5 to 20 parts by weight of a fluorine- By weight of the adhesive composition.

That is, since the adhesive composition of the present invention does not contain a halogen, it contains an optimal content of a specific fluorine-containing compound and a multifunctional curing agent for an epoxy resin while generating no harmful gas during combustion, and when applied to an electrically insulating substrate, It is possible to provide a coverlay film with improved migration.

Hereinafter, the adhesive composition of the present invention will be described in detail.

The halogen-free epoxy resin used in the present invention is an epoxy resin containing no halogen atom such as bromine in the molecule. The epoxy resin is not particularly limited and may contain silicon, urethane, polyimide, polyamide, etc., and may contain atoms other than halogen such as nitrogen, which is phosphorus in the structure. Examples of the epoxy resin applicable to the present invention include bisphenol A type epoxy resin, bisphenol F type epoxy resin, hydrogenated ones, phenol novolak type epoxy resins and cresol novolak type epoxy resins, A bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a phenol novolak type epoxy resin, and a cresol novolak type epoxy resin may be used.

Further, the phosphorus-containing epoxy resin having phosphorus atoms bonded thereto using a reactive compound can be used for constituting a flame retardant adhesive composition containing no halogen. The above-mentioned epoxy resins may be used alone or in combination of two or more.

The carboxyl group-containing acrylic rubber used in the present invention is a carboxyl group-modified acrylic rubber, and the carboxyl group-containing acrylonitrile butadiene rubber is preferably used.

At this time, the content of the carboxyl group is in the range of 0.05 to 8% by weight, preferably 0.05 to 2% by weight. At this time, it is preferable to use carboxyl-terminated butadiene acrylonitrile rubber (CTBN) as the carboxyl group-containing acrylonitrile butadiene rubber. Examples thereof include PNR-1H products of JSR and Nippol 1072 of ZEON.

The carboxyl group-containing acrylic rubber has elasticity as a rubber base and gives a curing reaction with the epoxy, thereby imparting an effect of satisfying flexibility and high peel strength to the adhesive composition. The acrylic rubber is contained in an amount of 50 to 80 parts by weight per 100 parts by weight of the non- If the amount is less than 50 parts by weight, low releasability is exhibited. If the amount is more than 80 parts by weight, high peel strength is exhibited but the adhesive surface is excessively tacky.

The multifunctional curing agent for epoxy resin used in the present invention functions to cure the resin and is preferably multifunctional having three or more acrylate functional groups. The multifunctional curing agent for epoxy resin is preferably used in two reactors A multi-network structure can be formed as compared with a conventional hardener having a low migration rate, thereby preventing the copper from growing during the migration evaluation, thereby improving migration characteristics.

The above-mentioned multifunctional curing agent for epoxy resins may be used alone or in combination of two or more of dicyandiamide, an amine compound, a compound synthesized from an amine compound, a tertiary amine compound, and a derivative thereof.

In this case, the multifunctional curing agent for epoxy resin is preferably contained in an amount of 15 to 20 parts by weight based on 100 parts by weight of the non-halogen-based epoxy resin. When the amount of the multifunctional curing agent for epoxy resin is less than 15 parts by weight, It is not cured and the migration property is insufficient. When the amount exceeds 20 parts by weight, the epoxy resin is excessively contained in curing the epoxy resin, resulting in a problem that the adhesive force is reduced.

The phosphorus-based flame retardant used in the present invention is a nitrogen-containing organic phosphoric acid compound and does not contain a halogen atom, so that the problem of the halogen-based flame retardant is usually solved. In this case, the phosphorus flame retardant may be contained in an amount of 10 to 200 parts by weight, more preferably 20 to 100 parts by weight, per 100 parts by weight of the non-halogen epoxy resin.

The fluorine-based compound used in the present invention is not particularly limited as long as it contains an epoxy functional group, and a structure having an epoxy functional group on one side and a fluorine group on the opposite side may be more preferably used. The above-mentioned fluorine-based compound reacts with the epoxy resin or the curing agent in reaction with the non-halogen-based epoxy resin and is present in the adhesive, so that the repulsive force, which is an intrinsic property of fluorine, increases the distance between the epoxy chains upon curing, The area of air or vacuum having a low dielectric constant is enlarged to lower the inherent permittivity of the adhesive composition.

In addition, the fluorine-based compound is preferably blended in an optimal amount to obtain desired physical properties, and is preferably applied in an amount of 5 to 20 parts by weight per 100 parts by weight of the non-halogen epoxy resin. If the content of the fluorine compound is less than 5 parts by weight, the effect of low dielectric constant is insignificant. If the content of the fluorine compound exceeds 20 parts by weight, the free volume is excessively increased, which hinders formation of a network structure during curing of the adhesive composition, .

In the adhesive composition of the present invention, a curing accelerator for accelerating the reaction between the non-halogen type epoxy resin and the multi-functional curing agent for epoxy resin may be selectively used. At this time, the curing accelerator is not particularly limited in kind, and may be selected from the group consisting of ethyl isocyanate compound, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole , Triphenylphosphine, etc. may be used alone or in combination of two or more, but the present invention is not limited thereto.

In this case, the curing accelerator may be contained in an amount of usually 0.1 to 15 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of the non-halogen epoxy resin.

The halogen-free epoxy resin, the carboxyl group-containing acrylic rubber, the multifunctional curing agent for epoxy resin, the phosphorus-based flame retardant and the fluorine-based compound can be mixed and stirred by a conventional method.

When the viscosity of the adhesive composition is less than 200 cps, the thickness of the adhesive sheet can not be controlled. When the viscosity of the adhesive composition is more than 1,000 cps, It is not preferable because many bubbles are generated.

Further, the present invention relates to a method for producing an epoxy resin composition, which comprises applying an adhesive composition comprising a non-halogen epoxy resin, a carboxyl group-containing acrylic rubber, a multifunctional curing agent for epoxy resin, a phosphorus- A film can be provided.

More specifically, 50 to 80 parts by weight of a carboxyl group-containing acrylic rubber, 15 to 20 parts by weight of a multifunctional curing agent for epoxy resin, 20 to 100 parts by weight of a phosphorus-based flame retardant, and 5 to 20 A thermosetting epoxy adhesive was prepared by transferring the adhesive to a portion of an electrically insulating substrate which continuously traveled in an air fan and then the substrate coated with the adhesive composition was passed through an inline drier to form 100 To 160 ° C for 2 to 10 minutes to remove the organic solvent to obtain a semi-cured state. The semi-cured composition layer is laminated with another mold release material using a roll laminator to provide a coverlay film can do.

At this time, the coverlay film of the present invention can be maintained at a low dielectric constant of 1.0 to 2.5.

The electrically insulating substrate is not particularly limited and can be a conventional electrically insulating substrate. The thickness of the electrically insulating substrate is 12.5 to 75 탆, preferably 12.5 to 25 탆. The release substrate is coated with polyethylene or silicone resin to impart peelability .

The thickness of the coating liquid may be controlled by the distance between the comma coater and the surface of the substrate. The coating method may be a gravure court method, a blade court method, a wire bar court method, A reverse court method, a comma court method, or the like can be used.

That is, the adhesive composition of the present invention contains no halogen and does not generate human toxic gas upon combustion, and contains a halogen-free epoxy resin, a carboxyl group-containing acrylic rubber, a multifunctional curing agent for epoxy resin, a phosphorus- In particular, it contains a specific fluorinated compound and a multifunctional curing agent for an epoxy resin in an optimal amount, and when applied to an electrically insulating substrate film, the low dielectric constant and immersion resistance are improved, and thus it is excellent as a coverlay film.

Hereinafter, the present invention will be described in detail with reference to examples.

The following examples illustrate the present invention, but the scope of the present invention is not limited to the following examples.

≪ Example 1 >

80 parts by weight of a carboxyl group-containing acrylonitrile-butadiene rubber (product of Nippon Zeon Co., Ltd., product of NIPOL 1072, -COOH: 8% by weight) as a non-halogen epoxy as a multifunctional curing agent for epoxy resin, 15 parts by weight of triallyl cyanurate (hereinafter referred to as TAC) manufactured by Toyo Chemical Co., Ltd.), 10 parts by weight of phosphorus-containing flame retardant, 50 parts by weight of aromatic phosphoric acid ester amide (product of Shikoku Chemicals Co., 3 parts by weight of 2-ethyl-4-methyl-imidazole (hereinafter, referred to as '2E4MZ') as a curing accelerator and 3 parts by weight of 3- [2- (perfluorohexyl) And 5 parts by weight of epoxypropane (hereinafter referred to as "PFEEP", Toyo Chemical Co., Ltd.) were mixed to prepare an adhesive composition, which was dissolved in methyl isobutyl ketone (MIBK) , Dried at 160 캜 for 2 minutes , By laminating a release substrate (130㎛) was prepared coverlay pilreumreul.

≪ Example 2 >

A coverlay film was produced in the same manner as in Example 1 except that 10 parts by weight of the fluorine-based compound PFEEP was added.

≪ Example 3 >

A coverlay film was produced in the same manner as in Example 1, except that 15 parts by weight of PFEEP as a fluorine compound was added.

<Example 4>

A coverlay film was produced in the same manner as in Example 1 except that 20 parts by weight of the fluorine-based compound PFEEP was added.

&Lt; Example 5 >

A coverlay film was produced in the same manner as in Example 1 except that 10 parts by weight of PFEE as a fluorine compound and 20 parts by weight of TAC as a multifunctional curing agent for an epoxy resin were added.

&Lt; Comparative Example 1 &

A coverlay film was produced in the same manner as in Example 1 except that PFEEP, which is a fluorine-based compound, was not contained.

&Lt; Comparative Example 2 &

A coverlay film was produced in the same manner as in Example 1 except that TAC as a multifunctional curing agent for epoxy resin was not contained.

&Lt; Comparative Example 3 &

A coverlay film was produced in the same manner as in Example 1 except that TAC as a multifunctional curing agent for epoxy resin and PFEEP as a fluorine-based compound were not contained.

&Lt; Comparative Example 4 &

A coverlay film was produced in the same manner as in Example 1 except that 4 parts by weight of the fluorine-based compound PFEEP was added.

&Lt; Comparative Example 5 &

A coverlay film was produced in the same manner as in Example 1 except that 25 parts by weight of PFEEP as a fluorine compound was added.

<Experimental Example>

1. Measurement of dielectric constant

The coverlay film prepared in Examples 1 to 5 and Comparative Examples 1 to 5 was placed between both electrodes in a vacuum state, an alternating current was flowed through the electrode, and the current flowing through the coverlay film was measured again in the detector And the average value thereof was indicated after five tests.

2. Measurement of migration

The coverlay films prepared in Examples 1 to 5 and Comparative Examples 1 to 5 were prepared as a test piece for evaluation of a single layer plate having the sectional structure shown in Fig. A pattern circuit having a line width / space width = 80 mu m / 80 mu m was fabricated on the flexible copper-clad laminate, and the coverlay film was formed on the circuit formation surface under the conditions of a temperature of 160 DEG C, a pressure of 44 kgf, To prepare a test piece for evaluation of a single layer plate.

A direct current voltage of 50 V was applied to the positive electrode of the circuit under the conditions of a temperature of 85 ° C and a relative humidity of 85% for the test piece prepared as described above, and the migration was measured. After 1000 hours, short- Is marked with X, and when not, it is marked with ○.

Evaluation items Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 The dielectric constant (epsilon) 2.5 1.7 1.6 1.3 1.8 3.9 2.6 4.0 3.0 1.1 Migration ○ ○ ○ ○ ○ × × × × ×

As can be seen from the above Table 1, Examples 1 to 5, in which the fluorinated compounds having the optimum contents according to the present invention and the multifunctional curing agent for epoxy resins were applied, showed lower permittivity and excellent migration migration characteristics than Comparative Examples 1 to 4 And when it is used as an adhesive for a coverlay film used for a flexible circuit board, high electrical reliability can be expected even when applied to a fine circuit pattern.

As a result, it was found that the adhesive composition of the present invention does not contain a halogen-based substance and does not generate harmful gas of human body during combustion, and when a micro-patterned flexible circuit board is bonded to an electrically insulating substrate, Since it is possible to provide a coverlay film, it is possible to improve the electrical reliability when applied to an electronic product, and it is particularly easy to apply a small electronic product.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

1 is a structural view of a coverlay film of the present invention,

2 is a cross-sectional view of an evaluation specimen for evaluating migration resistance according to an experimental example of the present invention.

Description of the Related Art [0002]

10 : electrically insulating substrate film

20 : Adhesive

30 : mold release substrate

40 : CCL (Copper Clad Laminate) pattern

50 : CCL (Copper Clad Laminate) Adhesive

60 : CCL (Copper Clad Laminate) Copper foil

Claims (5)

Relative to 100 parts by weight of the non-halogenated epoxy resin; 50 to 80 parts by weight of a carboxyl group-containing acrylic rubber; 15 to 20 parts by weight of a multifunctional curing agent for an epoxy resin; 20 to 100 parts by weight of a phosphorus flame retardant; 5 to 20 parts by weight of a fluorine-based compound having an epoxy functional group and a fluorine group; And 1 to 5 parts by weight of a curing accelerator; &Lt; / RTI &gt; The curing accelerator of claim 1, wherein the curing accelerator is selected from the group consisting of ethyl isocyanate compounds, 2-phenylimidazole, 2-phenyl-4-methylimidazole, Phenylphosphine. &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt; The adhesive composition of claim 1, wherein the adhesive composition has a viscosity of from 200 to 1,000 cps. A coverlay film having a dielectric constant of 1.0 to 2.5 in which an adhesive layer is formed by applying the adhesive composition of claim 1 on an electrically insulating film, and a release substrate is laminated on the adhesive layer. The adhesive composition according to claim 1, wherein the fluorine-based compound is 3- [2- (perfluorohexyl) ethoxy] -1,2-epoxypropane.

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