KR20100095195A - Adhesive composition and coverlay film using the same - Google Patents

Abstract

PURPOSE: An adhesive composition is provided to prevent the generation of harmful gas in combustion without including halogen and to be used as a coverlay film by improving permittivity and anti-migration when the adhesive composition is applied to a conductive substrate. CONSTITUTION: An adhesive composition comprises: 50-80 parts by weight of an acrylic rubber containing a carboxylic group; 15-20 parts by weight of a polyfunctional hardening agent; 20-100.0 parts by weight of flame retardant; and 5-20 parts by weight of a fluorine-based compound based on 100.0 parts by weight of a non-halogen epoxy resin. The viscosity of the adhesive composition is 200-1,000 cps. A method for forming a coverlay film includes a step of forming an adhesive layer(20) by spreading the adhesive composition on an insulating film(10) and a step of laminating a release substrate(30) on the adhesive layer.

Description

Adhesive composition and coverlay film to which it is applied {ADHESIVE COMPOSITION AND COVERLAY FILM USING THE SAME}

The present invention relates to an adhesive composition and a coverlay film to which the same is applied, and more particularly, to an adhesive composition containing a non-halogen epoxy resin, an acrylic rubber containing a carboxyl group, a multifunctional curing agent for an epoxy resin, a phosphorus flame retardant and a fluorine compound. And it is related with the coverlay film which applied this.

In recent years, with the rapid development of the integrated density of semiconductor integrated circuits and the surface mount technology for directly mounting small chip components and the miniaturization of electronic equipments in the electronics industry, it is necessary to facilitate the embedding in more complicated and narrow spaces. In order to meet these demands, flexible printed circuit boards have been developed.

In particular, in the case of high-use flexible printed circuit boards (FPCBs), demand for mobile phones, DVDs, digital cameras, and PDPs is rapidly increasing due to technological developments. It is true.

In general, a flexible circuit board used for assembling electronic devices is covered by forming a circuit pattern on an electrically insulating base film including an adhesive layer and a laminate base film composed of metal foil, and removing a release base material for temporary protection. It is produced by further laminating another insulating film obtained from the ray film.

At this time, the adhesive used for electronic materials, such as a semiconductor sealing material or an epoxy-type flexible circuit board, generally shows the outstanding flame retardance by mix | blending an epoxy resin, a phenoxy resin, etc. containing a bromine. However, when a compound containing halogen, such as bromine, is combusted, there is a possibility that harmful gases such as dioxins-based compounds may be generated, and therefore, non-halogenation of materials used for adhesives has recently been studied.

In addition, as the integration and miniaturization of electronic products, micro-patterning has become a major topic in electric and electronic fields such as semiconductors and flexible circuit boards, and thus, excellent electrical properties, low dielectric constant, Excellent migration is required.

Adhesives used in base films for flexible circuit boards as meeting the above requirements include various combinations of thermosetting resins, thermoplastic resins and fluorine-based compounds or elastomers. The adhesive compositions proposed thus far include blends of epoxy resins and nitrile butadiene rubbers (hereinafter referred to as 'NBR'), blends of epoxy resins and polyesters, blends of epoxy resins and acrylic resins, among others epoxy resins / NBR adhesive compositions are most widely used because of their superior adhesive strength compared to epoxy resin / acrylic resin adhesive compositions.

In addition, phosphorus flame retardants and inorganic flame retardants are widely used as flame retardants that do not contain halogen.

However, conventional adhesives still have a problem that low dielectric constant and good migration resistance for minimizing electrical interference between fine patterns are not sufficient.

Accordingly, the present inventors have endeavored to produce an adhesive for a coverlay film having excellent low dielectric constant and high migration resistance without containing halogen, resulting in an epoxy resin, an acrylic rubber containing a carboxyl group, a multifunctional curing agent for an epoxy resin, a phosphorus flame retardant, and The present invention was completed by preparing an adhesive composition containing an fluorine-based compound in an optimum ratio, and applying the same to a base film and then laminating a release substrate to confirm low dielectric constant and migration resistance of the coverlay film.

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

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

In order to achieve the above object, the present invention is 50 to 80 parts by weight of carboxyl group-containing acrylic rubber, 15 to 20 parts by weight of a multifunctional curing agent for epoxy resins, and 20 to 100 parts by weight of a phosphorus flame retardant based on 100 parts by weight of the non-halogen epoxy resin. And 5 to 20 parts by weight of a fluorine compound, wherein the adhesive composition is an ethyl isocyanate compound, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4-methyl-5 It may further contain 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 1,000cps.

Further, the present invention by applying the adhesive composition on the base film to form an adhesive layer, the release substrate is laminated on the adhesive layer to provide a coverlay film having a dielectric constant of 1.0 to 2.5.

The adhesive composition of the present invention does not contain halogen, and thus, does not generate harmful gases during combustion, and includes a specific fluorine-based compound and a multifunctional curing agent for an epoxy resin in an optimum content to ensure low dielectric constant when applied to an electrically insulating substrate. At the same time, it is possible to provide a coverlay film having excellent migration characteristics, thereby increasing electrical reliability when applied to electronic products.

The present invention is based on 100 parts by weight of the non-halogen epoxy resin, 50 to 80 parts by weight of 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 phosphorus flame retardant and 5 to 20 parts by weight of fluorine-based compound The adhesive composition which consists of parts is provided.

That is, since the adhesive composition of the present invention does not contain halogen, there is no harmful gas during combustion, and it contains a specific fluorine-based compound and a multifunctional curing agent for an epoxy resin in an optimum content, and when applied to an electrically insulating substrate, a low dielectric constant and 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 non-halogen epoxy resin used by this invention is an epoxy resin which does not contain halogen atoms, such as bromine, in a molecule | numerator. The epoxy resin is not particularly limited, and may contain silicone, urethane, polyimide, polyamide, and the like, and atoms other than halogens such as phosphorus and nitrogen may be included in the structure. Examples of the epoxy resins applicable to the present invention include bisphenol A type epoxy resins, bisphenol F type epoxy resins, or hydrogens added thereto, phenol novolac type epoxy resins, cresol novolac type epoxy resins, and the like. Preferably, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin can be used.

Moreover, various phosphorus containing epoxy resin which couple | bonded the phosphorus atom using the reactive phosphorus compound can be used when it comprises the flame-retardant adhesive composition which does not contain a halogen. The said epoxy resin can be used individually by 1 type, and can be used together 2 or more types.

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

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. In this case, the carboxyl group-containing acrylonitrile butadiene rubber is preferably the use of carboxyl-terminated butadiene acrylonitrile rubber (CTBN), and examples thereof include PSR-1H manufactured by JSR and Nippol 1072 manufactured by ZEON.

The carboxyl group-containing acrylic rubber has an elasticity as a rubber-based and gives an effect of satisfying the flexibility and high peel strength to the adhesive composition according to the curing reaction with the epoxy, 50 parts by weight to 80 parts by weight based on 100 parts by weight of non-halogen-based epoxy It is preferable to be contained by weight part, and when it is less than 50 weight part, it shows low peelability, and when it exceeds 80 weight part, it shows high peeling strength, but it is not preferable because an adhesive surface is too sticky.

The multifunctional curing agent for the epoxy resin used in the present invention serves to cure the resin, preferably a multifunctional having three or more acrylate functional groups, the multifunctional curing agent for the epoxy resin is two reactors during the curing reaction By forming a multi-network structure as compared to the general curing agent having a can prevent the growth of copper during migration evaluation can cause the effect of improving the migration characteristics.

The above-mentioned multifunctional curing agent for epoxy resins may be used alone or in combination of two or more such as dicyandiamide, amine compounds, compounds synthesized from amine compounds, tertiary amine compounds and derivatives thereof.

At this time, it is preferable that the said multifunctional hardening | curing agent for epoxy resins is contained 15-20 weight part with respect to 100 weight part of non-halogen-type epoxy resins, and when the multifunctional hardening | curing agent for epoxy resins is less than 15 weight part, an epoxy-type resin is fully Migration properties are not sufficient because it is not cured, and if more than 20 parts by weight, excessively contained to cure the epoxy-based resin occurs a problem that the adhesive force is reduced.

The phosphorus flame retardant used in the present invention is a nitrogen-containing organophosphate compound, and does not contain a halogen atom, so that the problem of the halogen flame retardant can usually be solved. At this time, the phosphorus flame retardant may contain 10 to 200 parts by weight, more preferably 20 to 100 parts by weight based on 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 a fluorine group on one side of the epoxy functional group may be more preferably used. When the fluorine-based compound reacts with the non-halogen-based epoxy resin and the epoxy group reacts with the epoxy resin or the curing agent and exists in the adhesive, the repulsive force, which is a fluorine intrinsic property, increases the distance between the epoxy chains during curing, thereby reducing the prevolume inside the adhesive composition. By increasing the area of low dielectric constant air or vacuum can lower the dielectric constant inherent in the adhesive composition.

In addition, the fluorine-based compound may be obtained by mixing the optimum content to obtain the desired physical properties, it is preferable that 5 to 20 parts by weight based on 100 parts by weight of the non-halogen epoxy resin. At this time, when the content of the fluorine-based compound is less than 5 parts by weight, the effect of low dielectric constant is insignificant, and when it exceeds 20 parts by weight, the prevolume is excessively increased, which hinders the formation of the network structure during curing of the adhesive composition, which is not preferable because the heat resistance becomes weak. .

In the adhesive composition of the present invention, a curing accelerator for promoting the reaction of the non-halogen-based epoxy resin and the multifunctional curing agent for the epoxy resin may be optionally used. In this case, the type of the curing accelerator is not particularly limited, ethyl isocyanate compound, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole Imidazole compounds such as, triphenylphosphine and the like may be used alone or in combination of two or more, but is not limited thereto.

At this time, the curing accelerator may be contained 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 non-halogen epoxy resin, carboxyl group-containing acrylic rubber, multifunctional curing agent for epoxy resin, phosphorus flame retardant and fluorine-based compound may be mixed and stirred in a conventional manner.

At this time, the viscosity of the stirred adhesive composition is 200 to 1,000cps, preferably 400 to 800cps, if the viscosity is less than 200cps can not control the thickness of the adhesive sheet when coating the adhesive composition, if it exceeds 1,000cps when stirring the adhesive composition It is not preferable because many bubbles are generated.

Furthermore, the present invention is a coverlay in which a release substrate is laminated after an adhesive composition composed of the above non-halogen epoxy resin, a carboxyl group-containing acrylic rubber, a multifunctional curing agent for an epoxy resin, a phosphorus flame retardant and a fluorine-based compound is applied onto an electrically insulating substrate. Films may be provided.

More specifically, 50 to 80 parts by weight of the carboxyl group-containing acrylic rubber, 15 to 20 parts by weight of the multifunctional curing agent for epoxy resins, 20 to 100 parts by weight of the phosphorus flame retardant and 5 to 20 of the fluorine compound based on 100 parts by weight of the non-halogen epoxy resin. After stirring uniformly by weight parts to prepare a thermosetting epoxy-based adhesive, transfer it to a pump and apply it to an electrically insulating substrate that is continuously running in an liquid fan (liquid fan), the substrate coated with the adhesive composition is passed through an inline dryer, 100 It is dried by removing the organic solvent from 2 to 10 minutes at 160 ℃ to a semi-cured state, and the composition layer of the semi-cured state is pressed and laminated with a separate release substrate using a roll laminator to provide a coverlay film can do.

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

The electrically insulating substrate is not particularly limited and a conventional electrically insulating substrate may be used, and the thickness thereof is 12.5 to 75 µm, preferably 12.5 to 25 µm, and the release substrate is coated with polyethylene or silicone resin to provide peelability. It is preferable.

In addition, the thickness of the coating liquid can be adjusted as the distance between the comma coater and the substrate surface, the coating method is a gravure court method, blade court method, wire bar court method, Reverse court method, comma court method and the like can be used.

That is, the adhesive composition of the present invention does not contain a halogen, there is no human harmful gas during combustion, and contains a non-halogen-based epoxy resin, carboxyl group-containing acrylic rubber, a multifunctional curing agent for epoxy resins, phosphorus-based flame retardants and fluorine-based compounds, In particular, it contains a specific fluorine-based compound and a multifunctional curing agent for epoxy resins in an optimum content, and when applied to an electrically insulating base film, the low dielectric constant and migration resistance is 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 are merely illustrative of the present invention, but the scope of the present invention is not limited to the following examples.

≪ Example 1 >

80 parts by weight of carboxyl group-containing acrylonitrile butadiene rubber (Nippon Xeon, Nippon 1072, -COOH: 8% by weight) based on 100 parts by weight of bisphenol F type as a non-halogen epoxy, and three functional groups as a multifunctional curing agent for epoxy resins. 15 parts by weight of triallyl cyanurate (hereinafter referred to as "TAC" manufactured by Toyo Chemical Co., Ltd.), aromatic phosphoric acid esteramide (products of Shikoku Kasei Kogyo Co., SP-703) 50 parts by weight of phosphorus as a phosphorus flame retardant. Parts by weight, 3-ethyl-4-methyl-imidazole (hereinafter referred to as '2E4MZ') as a curing accelerator, 3- [2- (perfluorohexyl) ethoxy] -1,2- as a fluorine compound 5 parts by weight of epoxy propane (hereinafter referred to as 'PFEEP') was prepared, an adhesive composition was prepared, dissolved in methyl isobutyl ketone (MIBK), and then coated on an electrically insulating substrate (12.5 μm) to a thickness of 25 μm. Apply to dry and dry at 160 ℃ for 2 minutes , By laminating a release substrate (130㎛) was prepared coverlay pilreumreul.

<Example 2>

A coverlay film was prepared in the same manner as in Example 1, except that 10 parts by weight of PFEEP, which was a fluorine compound, was added.

<Example 3>

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

<Example 4>

A coverlay film was prepared in the same manner as in Example 1, except that 20 parts by weight of PFEEP, which was a fluorine compound, was added.

<Example 5>

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

Comparative Example 1

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

Comparative Example 2

A coverlay film was prepared in the same manner as in Example 1, except that TAC, which is a multifunctional curing agent for epoxy resins, was not contained.

Comparative Example 3

A coverlay film was prepared in the same manner as in Example 1, except that TAC, which is a multifunctional curing agent for epoxy resins, and PFEEP, which was a fluorine compound, were not contained.

<Comparative Example 4>

A coverlay film was prepared in the same manner as in Example 1, except that 4 parts by weight of PFEEP, which was a fluorine compound, was added.

Comparative Example 5

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

Experimental Example

1. Dielectric constant measurement

The coverlay films prepared in Examples 1 to 5 and Comparative Examples 1 to 5 were placed between both electrodes in a vacuum state, and an alternating current was flowed through the electrodes, and then the current flowing through the coverlay film was measured again by a detector. The test was performed five times and the average value was indicated.

2. Measure migration

The coverlay films prepared in Examples 1 to 5 and Comparative Examples 1 to 5 were prepared as test pieces for monolayer plate evaluation having a cross-sectional structure shown in FIG. 2. The pattern circuit of line width / space width = 80 micrometers / 80 micrometers was manufactured to a flexible copper foil laminated board, and the coverlay film was used for the circuit formation surface using the press apparatus, the temperature of 160 degreeC, the pressure of 44 kgf, and the pressurization time of 30 minutes. It bonded together in the and prepared the test piece for single-layer board evaluation.

For the test specimens prepared as described above, migration was measured by applying a DC voltage of 50 V to the anode of the circuit at a temperature of 85 ° C. and a relative humidity of 85%, and short circuits between conductors or dendrites were generated after 1000 hours. The case of was denoted by x, and the case was indicated by ○.

Evaluation item 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 Permittivity (ε) 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 in Table 1, Examples 1 to 5 to which the optimum content of the fluorine-based compound and the multifunctional curing agent for epoxy resins according to the present invention have a low dielectric constant than Comparative Examples 1 to 4 and at the same time have excellent migration resistance. As can be seen, when used as an adhesive of the coverlay film used in the flexible circuit board can be expected high electrical reliability even when applied to the fine circuit pattern.

As a result of the above, the adhesive composition of the present invention does not contain a halogen-based material, there is no human harmful gas during combustion, and has excellent low dielectric constant and migration resistance when attaching a flexible circuit board having a fine pattern to an electrically insulating substrate. By providing a coverlay film, it is possible to increase the electrical reliability when applied to electronic products, in particular easy to apply small electronic products.

Although the present invention has been described in detail only with respect to the embodiments described, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical scope of the present invention, and such modifications and modifications belong to the appended claims.

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

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

<Code Description of Main Parts of Drawing>

10 : electrically insulating base film

20 : adhesive

30 : mold release material

40 : CCL (Copper Clad Laminate) Pattern

50 : CCL (Copper Clad Laminate) Adhesive

60 : CCL (Copper Clad Laminate) Copper Foil

Claims (4)

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 resins, 20 to 100 parts by weight of a phosphorus flame retardant and 5 to 20 parts by weight of a fluorine compound, based on 100 parts by weight of the non-halogen epoxy resin. Adhesive composition. The process according to claim 1, wherein the ethyl isocyanate compound, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole and triphenylphosphine Adhesive composition containing 1-5 weight part of further hardening accelerators chosen from the group which consisted of. The adhesive composition of claim 1, wherein the adhesive composition has a viscosity of 200 to 1,000 cps. A coverlay film having a dielectric constant of 1.0 to 2.5, by applying the adhesive composition of claim 1 on an electrically insulating film to form an adhesive layer, and a release substrate laminated on the adhesive layer.

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