KR101325985B1 - Non-halogen flame retardant adhesive composition and coverlay film using the same - Google Patents

Abstract

The present invention relates to a non-halogen flame retardant adhesive composition and a coverlay film using the same.
Non-halogen flame-retardant adhesive composition of the present invention (a) 20 to 50% by weight of bisphenol A-based epoxy resin and 50 to 80% by weight of phosphorus-containing epoxy resin is mixed with respect to 100 parts by weight of non-halogen epoxy resin, (b) 30 to 80 parts by weight of the acrylic thermoplastic resin, (c) 1 to 25 parts by weight of the curing agent for curing the epoxy resin, (d) 0.1 to 1 parts by weight of the curing accelerator and (e) 2 to 7 parts by weight of the phosphorus-based organic flame retardant, By mixing phosphorus-containing epoxy resin with epoxy resin, which is a basic resin, to increase the phosphorus content of the composition, and by using a reactive phosphorus organic flame retardant, it is possible to realize flame retardancy of UL94 V-0 level and to satisfy excellent adhesion and heat resistance. do. Therefore, the non-halogen flame-retardant adhesive composition of the present invention can be usefully used as a coverlay film for circuit protection of a flexible printed circuit board.

Description

Non-halogen flame retardant adhesive composition and coverlay film using same {NON-HALOGEN FLAME RETARDANT ADHESIVE COMPOSITION AND COVERLAY FILM USING THE SAME}

The present invention relates to a non-halogen flame-retardant adhesive composition and a coverlay film using the same, and more particularly, using a reactive phosphorus organic flame retardant, by mixing a phosphorus-containing epoxy resin with an epoxy resin which is a basic resin, thereby adjusting the phosphorus content of the composition. Non-halogen-based flame retardant adhesive composition which can not only realize the flame resistance of UL94 V-0 level by optimizing each composition and content of the composition to the extent that the adhesive composition is not gelated, but also excellent adhesiveness and heat resistance, and It relates to the used coverlay film.

Recently, as the density of electronic devices increases, the use range of flexible printed circuit boards to which flexibility is granted is expanding. Such flexible printed circuit boards contribute to the ultra-light weight and miniaturization of small and medium-sized electronic components such as mobile phones, digital cameras, notebook PCs, and the like. As it is used, it has established itself in the electronics field.

In order to multilayer printed circuit boards, an adhesive layer is necessarily required for interlayer adhesion between substrates or for adhesion between metal layers and substrates.

Currently, urethane-based resins, polyester-based resins, epoxy-based resins, phenol-based resins, and acrylic-based resins are mainly used as interlayer adhesives or adhesives for materials, but the resins contain halogen-based flame retardants such as bromine, which are vulnerable to environmental problems. Therefore, the interlayer adhesive or the adhesive for the material must meet not only physical properties such as heat resistance, adhesiveness, flame retardancy, flowability, etc., but also halogen-free requirements that solve environmental problems.

In order to meet these requirements, a method using a phosphorus-based flame retardant is applied. In general, inorganic particles are used as phosphorus-based flame retardants. In this case, problems such as deterioration in flexibility and decomposition when heat is applied are exposed, and finished coverlays using the same Silver causes a problem in that the cover lay adhesive surface discolors or bubbles during the solder process during the flexible printed circuit board (FPCB) process.

In particular, the above-described problems occur more frequently during high temperature and high humidity, such as during the rainy season. As an experiment to support this, when the RH% is set to 80 in a thermo-hygrostat and the moisture absorption of the coverlay materials is measured by a moisture meter, It can be seen that moisture absorption occurs in the particles.

In addition, the thermal stability can also confirm the thermal decomposition or melting of the flame-retardant inorganic particles as a result of measuring the thermal stability in a high temperature phase of 300 ℃ through the TGA. When such pyrolysis occurs, bubbles are likely to occur during the soldering process.

When contained in order to impart flame retardancy, in the case of particulates, dispersion is very important during coating. If the dispersion is not good, the particles may act as foreign matters, and in the case of inorganic particles, adhesion of the interface may be weaker than adhesion between organic resins, thereby affecting flexibility.

Flame retardants are largely classified into reactive and additive types. In the case of reactive flame retardants, since they are fixed in cured resins, there is a problem of separation from resin due to pressing of products containing reactive flame retardants or long-term storage. Is resolved. However, in the case of the reactive flame retardant, since the content of phosphorus atoms is small, it is necessary to contain a large amount of flame retardant, so that the adhesiveness tends to be lowered.

On the other hand, since the added flame retardant is higher in phosphorus content than the reaction type, the content of the flame retardant to be added may be reduced while separation from the resin may occur. In addition, since the additive-based flame retardant is independently dispersed in the resin, when the melting point is low, since the press is usually performed at 130 ° C. or higher, it may leak out during compression, so that the flame retardancy of the UL94 VO level is not achieved, and the appearance defect is a problem. Also occurs.

Accordingly, the present inventors have tried to solve the conventional problems, and as a result, avoid using flame retardant inorganic particles, use reactive phosphorus organic flame retardant, increase phosphorus content by mixing phosphorus epoxy resin with epoxy resin which is a basic resin, and adhesive composition. By confirming that the non-halogen flame-retardant adhesive composition, which has optimized each composition and content of the composition in the non-gelling range, not only can achieve the flame resistance of UL94 V-0 level, but also satisfies excellent adhesion and heat resistance. The invention was completed.

It is an object of the present invention to provide a non-halogen flame retardant adhesive composition with optimized composition and content of a composition that achieves UL94 V-0 level flame retardancy.

Another object of the present invention is to provide a coverlay film comprising, in one configuration, an adhesive layer formed by using the non-halogen flame-retardant adhesive composition.

In order to achieve the above object, the present invention (a) 20 to 50% by weight of bisphenol A-based epoxy resin and 50 to 80% by weight of phosphorus-containing epoxy resin mixed with 100 parts by weight of the non-halogen-based epoxy resin,

(b) 30 to 80 parts by weight of the acrylic thermoplastic resin,

(c) 1 to 25 parts by weight of a curing agent for curing the epoxy resin,

(d) 0.1 to 1 parts by weight of a curing accelerator and

(e) It provides a non-halogen flame-retardant adhesive composition consisting of 2 to 7 parts by weight of a reactive phosphorus organic flame retardant.

The non-halogen flame-retardant adhesive composition of the present invention is characterized in that the epoxy resin as the base resin is mixed with 20 to 50% by weight of bisphenol A-based epoxy resin and 50 to 80% by weight of phosphorus-containing epoxy resin. The reactive phosphorus compound is used in which 2 to 3.5% by weight of the phosphorus component is contained in the epoxy resin.

In addition, the non-halogen flame-retardant adhesive composition is to use a reactive phosphorus organic flame retardant, the preferred compound is a compound represented by the following formula (1).

Formula 1

(Where m and n are integers of 0 and 1, p is 0 to 2, and m and n are not zero at the same time.)

At this time, the phosphorus content in the reactive phosphorus organic flame retardant preferably contains at least 15% by weight or more.

It is preferable that the non-halogen-type flame-retardant adhesive composition containing the above composition has 20 to 40 weight% of solid content of the composition containing said (a) composition-(e) composition.

At this time, the viscosity of the non-halogen flame-retardant adhesive composition is preferably 250 to 1,550 cps.

The present invention is an electrically insulating base film; An adhesive layer formed of at least one surface of the base film, the non-halogen flame retardant adhesive composition; And a release member on which a release paper or a release film is laminated on the adhesive layer. The coverlay film has a UL94 V-0 level of flame retardancy.

At this time, the thickness of the adhesive layer which is one component in the coverlay film of this invention is 10-50 micrometers.

The non-halogen flame retardant adhesive composition according to the present invention uses a reactive phosphorus organic flame retardant, mixes a phosphorus-containing epoxy resin with an epoxy resin, which is a basic resin, increases the phosphorus content of the composition, and the composition does not gel. Optimize the composition and content of each.

In addition, not only the flame retardancy of UL94 V-0 level is realized from the non-halogen flame-retardant adhesive composition of the present invention, but also meets the physical properties such as adhesion, heat resistance, bending resistance, bleed-out resistance, and flow characteristics required in the field of coverlay film. Thus, the present invention can provide a coverlay film comprising an adhesive layer formed of a non-halogen flame retardant adhesive composition in one configuration.

Furthermore, the coverlay film prepared from the non-halogen flame-retardant adhesive composition is useful for circuit protection of a flexible printed circuit board, as it meets the required physical properties.

The present invention relates to 100 parts by weight of a non-halogen epoxy resin (a) 20 to 50% by weight of bisphenol A-based epoxy resin and 50 to 80% by weight of phosphorus-containing epoxy resin are mixed.

(b) 30 to 80 parts by weight of the acrylic thermoplastic resin,

(c) 1 to 25 parts by weight of a curing agent for curing the epoxy resin,

(d) 0.1 to 1 parts by weight of a curing accelerator, and

(e) It provides a non-halogen flame-retardant adhesive composition consisting of 2 to 7 parts by weight of a reactive phosphorus organic flame retardant.

Hereinafter, the flame retardant epoxy adhesive composition will be described in detail by composition.

(a) Non-halogen epoxy resin

In the adhesive composition of the present invention, the non-halogen epoxy resin is a polyfunctional non-halogen epoxy resin having two or more epoxy groups per molecule, and the equivalent (g / eq) of epoxy in the non-halogen epoxy resin is 200 to 1000. desirable.

As a preferable example, it can select from the group which consists of a bisphenol-A epoxy resin, a bisphenol F-type epoxy resin, a phenol novolak-type epoxy resin, a naphthalene type epoxy resin, a cresol-type epoxy resin, and a polyfunctional phenol glycidyl ether. More preferably, bisphenol A type epoxy resin or phenol novolak type resin is used.

Thus, the adhesive composition of the present invention improves flame retardancy of the entire adhesive composition by mixing phosphorus-containing non-halogen epoxy resin with the non-halogen epoxy resin in order to achieve flame retardancy of UL94 V-0 level.

The phosphorus-containing non-halogen epoxy resin is prepared by bonding a phosphorus atom to an epoxy resin using a reactive phosphorus compound, and a phosphorus content of 2 to 3.5% by weight is used. Preferred examples thereof include Totoseisei FX305 containing 3% by weight phosphorus and EXA9710 from Epikron Dainippon Ink & Chemicals Co., Ltd., and SEN275MC75 from Shina T & C containing 2.3% by weight phosphorus and 3.2% by weight of phosphorus. Available in select SEN320PM60 products.

Preferred non-halogen epoxy resins of the present invention are characterized in that 20 to 50% by weight of bisphenol A-based epoxy resin and 50 to 80% by weight of phosphorus-containing epoxy resin are mixed.

At this time, when the content of the phosphorus-containing epoxy resin is less than 50% by weight, the bisphenol A-based epoxy resin content is increased to increase the adhesive strength, but the flame retardancy to meet the UL94V-0 standard is not achieved, while the phosphorus-containing epoxy resin content If it exceeds 80% by weight, the adhesive force is reduced, which is not preferable.

(b) acrylic thermoplastic resin

It is preferable to use an acrylic resin as a thermoplastic resin among the adhesive compositions of this invention, More preferably, what copolymerized a carboxyl group or an epoxy group in the molecular chain terminal of an acrylic resin is used.

As the most preferable example, in the embodiment of the present invention, carboxyl group-containing acrylonitrile-butadiene rubber (hereinafter referred to as NBR) is used, wherein 4 to 8% by weight of the carboxyl group is copolymerized to 30 to 70% by mass of acrylonitrile, thereby The terminal of the molecular chain is carboxylated. At this time, the molecular weight of the carboxyl group-containing acrylonitrile-butadiene rubber is 10,000 to 200,000.

In the non-halogen flame-retardant adhesive composition of the present invention, the acrylic thermoplastic resin preferably contains 30 to 80 parts by weight based on 100 parts by weight of the non-halogen epoxy resin. At this time, when the acrylic thermoplastic resin content is less than 30 parts by weight, the decrease in adhesive strength and heat resistance is greatly reduced, when it exceeds 80 parts by weight, the glass transition temperature rises, the adhesive is too brittle and the film is maintained. Is impossible.

(c)

If it is used as a curing agent of the epoxy resin can be used without particular limitation, examples thereof include an acid anhydride, phenol resin or amine curing agent.

However, when a curing agent composed only of a phenol resin is used, discoloration may occur during the thermocompression bonding process, and since the reaction temperature is low, flowability is poor in that there is a risk of deterioration with time stability. Thus, the curing time is faster than the time to fill the pattern in the thermocompression process is hardened before all the pattern is filled to fail to meet this results in appearance defects.

Therefore, it is preferable to use a phenol resin in parallel with another hardening | curing agent.

In addition, in the case of the acid anhydride, when used alone, since the viscosity and adhesive force is very high, it is not preferable in processability, it is preferable to mix with other curing agents.

In the case of the amine-based curing agent, the aliphatic is usually used because the lower the reaction temperature to impair the stability over time, aromatic amine is used, in this case it is preferable to use a curing accelerator in parallel because the reaction temperature is high. In such cases, the type and amount of curing accelerator may be determined after due consideration of reactivity.

In the non-halogen-based flame retardant adhesive composition of the present invention, the content of the curing agent is preferably 1 to 25 parts by weight based on 100 parts by weight of the non-halogen-based epoxy resin.

(d) curing accelerator

Depending on the selection of the curing agent component (c), the addition, type and content of the curing accelerator will be determined.

Preferred curing accelerators include imidazole compounds such as 2-methyl imidazole, 2-ethyl-4-methyl imidazole and 2-phenyl-4-methyl imidazole, triphenylphosphine, tetraphenylphosphine and tetraphenyl Phosphine-based compounds such as borate or boron fluoride metal compounds such as zinc fluoride and boron fluoride. The compounds may be used singly or in combination of two or more depending on the degree of reaction of the epoxy curing agent. In the non-halogen flame-retardant adhesive composition of the present invention, the preferable content of the curing accelerator is 0.1 to 1.0 parts by weight based on 100 parts by weight of the non-halogen-based epoxy resin. If the content of the curing accelerator is less than 0.1 parts by weight, the reaction effect of the epoxy resin and the curing agent will be insufficient. If the content is more than 0.1 parts by weight, the miscibility with other compositions is low and the curing rate is faster than the reaction rate.

(e) Reactive Phosphorus Organic Flame Retardants

The flame retardant of the present invention is to use a reactive phosphorus organic flame retardant represented by the following formula (1) as phenylene methyl phosphonate.

Formula 1

(Where m and n are integers of 0 and 1, p is 0 to 2, and m and n are not zero at the same time.)

In the reactive phosphorus organic flame retardant of the present invention, the phosphorus content is preferably at least 15% by weight or more, and more preferably, the phosphorus content is contained within the range of 15 to 18% by weight. The reactive phosphorus-based organic flame retardant has a temperature of 300 deg. C or higher, but the melting point is 50 deg. C, but the reaction type will not be significantly affected.

In the non-halogen-based flame retardant adhesive composition of the present invention, the higher the content of the organic reactive organic flame retardant is advantageous to implement flame retardancy, but when contained in excess, the gelation reaction of the composition occurs, the preferred content of the organic reactive organic flame retardant is a gelation reaction It should be optimized to the content range before this occurs.

Thus, the organic reactive organic flame retardant of the present invention preferably contains 2 to 7 parts by weight based on 100 parts by weight of the non-halogen epoxy resin. At this time, if the content of the organic reactive organic flame retardant is less than 2 parts by weight, the flame retardant grade UL94 V-0 cannot be achieved, whereas if the content of the organic reactive organic flame retardant exceeds 7 parts by weight, it becomes a gel when added and coated. This is impossible and cannot be produced in film form.

The non-halogen-based flame retardant adhesive composition containing the components (a) to (e) described above preferably has a solid content of 20 to 40% by weight. At this time, methyl ethyl ketone, dimethylformamide, methyl isobutyl ketone, toluene or the like can be used as the solvent.

If the content of the solid content is less than 20% by weight, staining occurs on the coated surface when the solvent is dried, and when the content exceeds 40% by weight, it is difficult to control and handle the coating thickness. The non-halogen flame-retardant adhesive composition has a viscosity of 250 to 1550 cps.

The present invention provides a coverlay film using the non-halogen flame retardant adhesive composition.

More specifically, the electrically insulating base film;

An adhesive layer formed of at least one surface of the base film, the non-halogen flame retardant adhesive composition; And

It provides a coverlay film consisting of; a release member on which a release paper or a release film is laminated on the adhesive layer.

The coverlay film of the present invention is coated on an electrically insulating base film using an inline coating-dryer, and then heated at 50 to 130 ° C. for 1 to 10 minutes to volatilize the organic solvent, and to dry and cure the adhesive composition to a semi-cured state. To form an adhesive layer. Thereafter, the adhesive layer is manufactured by laminating with a release paper or a release film to form a release member layer.

At this time, the coverlay film of the present invention is preferably 10 to 50㎛ thickness of the adhesive layer after drying, if less than 10㎛, the adhesive layer is not enough to cover the pattern of the circuit, the flowability is less as a coverlay film If it is difficult to use, and exceeds 50㎛, not only does not meet the thin film requirements, but also the flexibility is impaired, the thickness beyond that to fill the pattern is disadvantageous in terms of bleed out resistance because there is more than necessary resin.

Hereinafter, the present invention will be described in more detail with reference to Examples. This is for further illustrating the present invention, and the scope of the present invention is not limited to these examples.

≪ Example 1 >

60 wt% of the non-halogen-based phosphorus epoxy resin (Shin-a T & C company name SEN320PM60) with an epoxy equivalent of 320 and 40 wt% of the non-halogen-based bisphenol-A epoxy resin (JSR PNR-1H) having a molecular weight of 300,000. 50 weight part of nitrile butadiene rubbers (NBR) with respect to 100 weight part of epoxy resins, 4 weight part of 4, 4- diamino diphenyl sulfones as an aromatic diamine type hardening | curing agent, and 2 ethyl-4 methyl imidazole as a hardening accelerator (made by Shikoku Chemical Co., Ltd.). ) 5 parts by weight of an organophosphorous flame retardant containing 0.4 parts by weight and 17.5% by weight of phosphorus was prepared. The prepared crude liquid was coated on a polyimide film and then dried at 130 ° C. for 3 minutes to prepare a coverlay film having a thickness of 25 μm after coating.

<Example 2>

Epoxy consisting of 80% by weight of non-halogen-based phosphorous epoxy resin (Shin-A T & C, product name SEN320PM60) of epoxy equivalent 320 and 20% by weight of non-halogen-based BPA epoxy resin (JSR PNR-1H) of 300,000 molecular weight Except for using the resin, the coverlay film was prepared in the same manner as in Example 1.

&Lt; Comparative Example 1 &

Epoxy consisting of 90% by weight of non-halogen-based BPA-based epoxy resin (JSR PNR-1H) of 10% by weight based on solid content and non-halogen-based phosphorous epoxy resin (Shin-A T & C, product name SEN320PM60) having an epoxy equivalent of 320 Except for using the resin, the coverlay film was prepared in the same manner as in Example 1.

Comparative Example 2

Epoxy consisting of 90% by weight of non-halogen-based BPA-based epoxy resin (JSR PNR-1H) of 10% by weight based on solid content and non-halogen-based phosphorous epoxy resin (Shin-A T & C, product name SEN320PM60) having an epoxy equivalent of 320 A coverlay film was prepared in the same manner as in Example 1, except that resin was used and 20 parts by weight of an organic phosphorus flame retardant was used.

&Lt; Comparative Example 3 &

Inorganic phosphorus flame retardant is used in an amount of 25 parts by weight of an inorganic phosphorus flame retardant, using an epoxy resin composed of 100% by weight of a non-halogen-based phosphoric epoxy resin having an epoxy equivalent of 320 and a molecular weight of 300,000 non-halogen-based BPA-based epoxy resin (JSR PNR-1H). Except for using, the same procedure as in Example 1 was carried out to prepare a coverlay film.

&Lt; Comparative Example 4 &

Epoxy consisting of non-halogen-based BPA-based epoxy resin (JSR PNR-1H) of 60 wt% based on solids and non-halogen-based phosphorous epoxy resin (Shin-A T & C, product name SEN320PM60) with an equivalent weight of 320 A coverlay film was prepared in the same manner as in Example 1, except that resin was used and 10 parts by weight of an organophosphorous flame retardant was used.

Experimental Example 1 Measurement of Peel Strength

The coverlay films prepared in Examples 1 to 2 and Comparative Examples 1 to 4 were cut to 1 cm in width and 10 cm in length after being attached to a 35 μm thick electrolytic copper foil using a hot press at 160 ° C./40 kgf / 30 minutes. After that, the polyimide film is fixed, the copper foil is pulled at a speed of 50 mm / min in the direction of 90 ° C, the force at that time is measured, and the minimum value thereof is represented by the adhesive force (JIS C6481).

Experimental Example 2 Evaluation of Solder Heat Resistance

The test piece was produced by cutting the flexible copper clad laminate to 25 mm in width and length, and the test piece was floated in a solder bath at a constant temperature for 30 seconds. The temperature of the solder bath was changed, and the maximum temperature at which expansion, peeling and discoloration did not occur in the test piece was measured. (JIS C6481)

Experimental Example 3 Flame Retardant Evaluation

Samples were prepared by laminating a polyimide film (trade name: LN050, manufactured by SKCKOLON, thickness: 12.5 μm) on an adhesive composition layer of a coverlay film using a hot press at 160 ° C./40 kgf / 40 minutes. Then, the flame retardancy of the compressed sample was measured according to the flame retardancy criterion UL94V-0. If the sample exhibits flame retardancy that meets the UL94V-0 criteria, it is evaluated as "good", while if the sample does not meet the UL94V-0 criteria, it is evaluated as "bad".

From the results in Table 1, it was confirmed that the adhesive force was lowered as the content of the phosphorus-containing epoxy resin in the composition (a) of the present invention increases. However, the coverlay film of Comparative Example 1 containing 90% by weight of bisphenol A-based epoxy resin and 10% by weight of phosphorus-containing epoxy resin had the best adhesion but could not be applied because it did not meet the UL94V-0 standard and had poor flame retardancy. .

In addition, in the case of Comparative Example 2 and Comparative Example 4 in which the content of the reactive organophosphorus-based flame retardant was used excessively, the coating itself was difficult due to partial gelation of the adhesive composition, and thus measurement was impossible.

In addition, when the conventional inorganic phosphorus-based flame retardant was used, the results of Comparative Example 3 showed lowered results in all evaluations of adhesion, heat resistance, and flame resistance.

As described above, the present invention uses a reactive phosphorus organic flame retardant, by using a phosphorus-containing epoxy resin in the epoxy resin of the base resin to increase the phosphorus content of the entire adhesive composition, thereby lowering the phosphorus of the conventional reactive phosphorus organic flame retardant The problem with the content was solved to provide a non-halogen flame-retardant adhesive composition that implements a flame retardancy of UL94 V-0 level.

Thus, the non-halogen flame-retardant adhesive composition of the present invention, by satisfying the properties such as adhesion, heat resistance, flexibility, bleed-out resistance and flow properties required in the field of coverlay film with high flame retardancy, non-halogen flame-retardant adhesive composition It is possible to improve the physical properties of the coverlay film having a tackifier layer formed.

Furthermore, the coverlay film prepared from the non-halogen flame-retardant adhesive composition is useful for circuit protection of a flexible printed circuit board, as it meets the required physical properties.

While the invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (8)

(a) 20 to 50% by weight of bisphenol A-based epoxy resin and 50 to 80% by weight of phosphorus-containing epoxy resin are mixed with respect to 100 parts by weight of non-halogen epoxy resin,
(b) 30 to 80 parts by weight of the acrylic thermoplastic resin,
(c) 1 to 25 parts by weight of a curing agent for curing the epoxy resin,
(d) 0.1 to 1 parts by weight of a curing accelerator, and
(e) A non-halogen flame retardant adhesive composition comprising 2 to 7 parts by weight of a reactive phosphorus organic flame retardant having a phosphorus content of at least 15% by weight or more. The non-halogen flame-retardant adhesive composition according to claim 1, wherein the phosphorus-containing epoxy resin contains 2 to 3.5% by weight of the phosphorus component in the epoxy resin using a reactive phosphorus compound. The non-halogen flame-retardant adhesive composition of claim 1, wherein the (e) phosphorus-based organic flame retardant is a compound represented by the following Chemical Formula 1.
Formula 1

M and n are integers of 0 and 1, p is 0 to 2, and m and n are not zero at the same time. delete The non-halogen-based flame retardant adhesive composition according to claim 1, wherein the solid content of the composition containing the composition (a) to (e) is 20 to 40% by weight. The non-halogen flame retardant adhesive composition of claim 1, wherein the non-halogen flame retardant adhesive composition has a viscosity of 250 to 1,550 cps. Electrically insulating base film;
An adhesive layer formed of at least one surface of the base film, the non-halogen flame-retardant adhesive composition of claim 1; And
A coverlay film having a flame retardancy of UL94 V-0 level formed by a release member having a release paper or a release film laminated on the adhesive layer. The coverlay film of claim 7, wherein the adhesive layer has a thickness of 10 to 50 μm.