KR101414815B1 - Halogen-free coverlay adhesive composition and coverlay film using the same - Google Patents

Abstract

The present invention relates to a halogen-free coverlay adhesive composition and a coverlay film using the same. More particularly, the present invention relates to a halogen-free coverlay adhesive composition having superior flame retardancy and adhesive strength than conventional adhesive compositions and a coverlay film using the same. The halogen-free coverlay adhesive composition according to the present invention comprises (a) 100 parts by weight of an epoxy resin, (b) 50 to 250 parts by weight of a carboxyl group-containing acrylonitrile butadiene rubber, and (c) (E) from 20 to 100 parts by weight of a phosphorus-based flame retardant and (f) from 20 to 100 parts by weight of an inorganic flame retardant; and (d) from 1 to 50 parts by weight of at least one curing agent selected from amine- .

Epoxy resin, acrylonitrile butadiene rubber, polyester resin, hardener, phosphorus flame retardant, inorganic flame retardant

Description

HALOGEN-FREE COVERLAY ADHESIVE COMPOSITION AND COVERLAY FILM USING THE SAME [0002]

The present invention relates to a halogen-free coverlay adhesive composition and a coverlay film using the same. More particularly, the present invention relates to a halogen-free coverlay adhesive composition having superior flame retardancy and adhesive strength than conventional adhesive compositions and a coverlay film using the same.

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

BACKGROUND ART Adhesives used in electronic materials such as semiconductor sealing materials and epoxy-based flexible circuit boards exhibit excellent flame retardancy by blending an epoxy resin containing bromine and phenoxy resin. When halogen-containing compounds such as bromine are burned, harmful gases such as dioxin compounds may be generated. Therefore, non-halogenation of materials used in adhesives has been studied recently.

The adhesive used for the substrate sheet for the flexible circuit board which satisfies the above requirements includes various combinations of thermosetting resin and thermoplastic resin or elastomer. The adhesive compositions proposed so far include a combination of an epoxy resin and an NBR, a combination of an epoxy resin and a polyester, a combination of an epoxy resin and an acrylic resin, and the epoxy resin / NBR adhesive composition is an epoxy resin / acrylic resin adhesive composition And is most widely used because of its excellent bonding strength. As the flame retardant containing no halogen, a phosphorus flame retardant and an inorganic flame retardant are widely used.

The flexible circuit board and the base sheet for the flexible circuit board must satisfy requirements for various characteristics including adhesive strength, heat resistance, solvent resistance, electrical characteristics, dimensional stability, long-term thermal stability and the like. In addition, the flexible circuit board is required to have an excellent adhesive strength, but it is also required to have an improved adhesive force because it further lowers adhesion due to moisture absorption or heat resistance.

It is an object of the present invention to provide a halogen-free coverlay adhesive composition which is superior in flame retardancy and adhesion to a conventional adhesive composition and a coverlay film using the same.

(B) 50 to 250 parts by weight of a carboxyl group-containing acrylonitrile butadiene rubber; (c) 10 to 100 parts by weight of a polyester resin or a phosphorus-containing polyester resin; and (d) (E) from 20 to 100 parts by weight of a phosphorus-based flame retardant and (f) from 20 to 100 parts by weight of an inorganic flame retardant. do.

The polyester resin (c) has a number average molecular weight of 3,000 to 20,000.

The present invention also provides a coverlay film using the halogen-free coverlay adhesive composition, comprising: an electrically insulating substrate film; an adhesive layer coated with the halogen-free coverlay adhesive composition on the electrically insulating substrate film; And a cover-lay film using a halogen-free coverlay adhesive composition comprising a release paper laminated on the release layer.

INDUSTRIAL APPLICABILITY According to the present invention, it has an effect such as superior flame retardancy and adhesive force than conventional adhesive compositions.

Hereinafter, the present invention will be described in detail with reference to embodiments and drawings of the present invention. It will be apparent to those skilled in the art that these embodiments are merely illustrative of the present invention in order to more particularly illustrate the present invention and that the scope of the present invention is not limited by these embodiments. will be.

The halogen-free coverlay adhesive composition according to the present invention is a homogeneous mixture and is characterized by containing the following components (a) to (f).

(a) 100 parts by weight of an epoxy resin,

(b) 50 to 250 parts by weight of a carboxyl group-containing acrylonitrile butadiene rubber,

(c) 10 to 100 parts by weight of a polyester resin or a phosphorus-containing polyester resin,

(d) 1 to 50 parts by weight of at least one curing agent selected from the group consisting of an amine type and an acid anhydride type,

(e) 20 to 100 parts by weight of a phosphorus flame retardant,

(f) 20 to 100 parts by weight of an inorganic flame retardant.

The epoxy resin (a) in the composition is preferably a polyfunctional epoxy resin having two or more epoxy groups in the molecule. There are several different types of epoxy resins, including, for example, bisphenol A based epoxy resins, bisphenol novolak based epoxy resins, and glycidyl amine based epoxy resins.

The carboxyl group-containing acrylonitrile butadiene rubber (b) in the composition is a carboxyl group-modified acrylic rubber. The content of the carboxyl group is 0.05 to 4% by weight, preferably 0.05 to 2% by weight, (Hereinafter, referred to as the same reference) of 50 to 250 parts by weight of a carboxyl group-containing acrylonitrile butadiene rubber.

The polyester resin (c) in the composition is a polyester resin containing phosphorus or having a different molecular weight, which contributes to an increase in adhesion of the cured product. The content of the polyester resin is 10 to 100 parts by weight, preferably 10 to 50 parts by weight.

In the composition, (d) the curing agent is a curing agent of an epoxy resin, and is at least one curing agent selected from an aromatic amine curing agent and an acid anhydride curing agent. The content of the curing agent is 1 to 50 parts by weight.

Among the above compositions, (e) the phosphorus flame retardant is a nitrogen-containing organic phosphate compound. Is a component which imparts excellent flame retardancy to a cured product and usually does not contain a halogen atom. The content of the phosphorus flame retardant is 20 to 100 parts by weight, preferably 50 to 100 parts by weight.

The inorganic flame retardant (f) in the composition is preferably aluminum hydroxide or magnesium hydroxide. The content of the inorganic flame retardant is 20 to 100 parts by weight, preferably 50 to 100 parts by weight.

The adhesive layer composed of the halogen-free coverlay adhesive composition having the above composition has a viscosity of 100 to 2000 CPS, preferably 400 to 1500 CPS.

Further, the coverlay film using the halogen-free coverlay adhesive composition according to the present invention comprises an electrically insulating substrate film, an adhesive layer coated thereon, and a release paper laminated on the adhesive layer. FIG. 1 is a cross-sectional view of a coverlay film according to an embodiment of the present invention in which an adhesive layer 20 is coated on a polyimide film 10 as an insulating substrate film, and a release paper 30 is formed on an upper surface of the adhesive layer. Are laminated. That is, the coverlay film of the present invention is a laminated sheet member comprising an electrically insulating base film and a releasable protective sheet attached to the base film by interposing a semi-cured layer of the above-described adhesive composition. The substrate sheet for the flexible circuit board of the present invention is a laminated sheet member comprising an electrically insulating flexible plastic resin film and a metal foil adhered to the flexible plastic resin film by the interposition of the cured layer of the adhesive composition defined above.

In the coverlay film according to the present invention, the thickness of the release paper is 50 to 200 占 퐉, preferably 100 to 150 占 퐉. The releasing paper was coated with polyethylene or silicone resin to give peelability.

The coverlay film according to the present invention is formed by applying an adhesive composition on an electrically insulating plastic resin film so that the thickness after drying is 10 to 30 占 퐉, curing the coated film at 100 to 200 占 폚 for 2 to 10 minutes, .

More specifically, a sufficiently stirred thermosetting epoxy adhesive is applied by a pump to a substrate film which continuously travels in a liquid fan. The thickness of the coating liquid at this time can be adjusted as a distance between the comma coater and the surface of the base film . The wet coating applied on the surface is dried while passing through the dryer zone, and the thickness of the coated layer after drying is 10 to 30 μm. In addition, as a method of applying the coating liquid to the plate-shaped object to be continuously run in the past, a gravure court method, a blade court method, a wire bar court method, a reverse court ) Method, and a comma court method. Thus, an adhesive film for electronic materials can be manufactured through various apparatuses for coating various coating liquids.

[Example 1]

160 parts by weight of NBR containing a carboxyl group, 40 parts by weight of a polyester resin (Vylon 220, Mn: 3k, Tg: 53 캜, manufactured by Toyobo Co., Ltd.), 40 parts by weight of DDM (Diaminodiphenyl methane) 70 parts by weight of SPB-100 as a phosphorus flame retardant, and 40 parts by weight of H-42I as an inorganic flame retardant were mixed to prepare a mixed solution. The mixed solution was dissolved in methyl ethyl ketone and then milled by a milling machine to be coated on a polyimide film And dried for 3 minutes to prepare a coverlay film having a thickness of 25 mu m after coating.

[Example 2]

Except that 80 parts by weight of the polyester resin (Vylon 220) was added under the conditions of Example 1.

[Example 3]

Except that 40 parts by weight of Vylon 200 (Mn: 17k, Tg: 67 ° C, manufactured by Toyobo) was used instead of Vylon 220 as a polyester resin under the conditions of Example 1.

[Comparative Example 1]

The same procedure as in Example 1 was carried out except that the polyester resin Vylon 220 was not used under the conditions of Example 1.

The coverlay films produced by the above Examples and Comparative Examples were evaluated using the following experimental examples, and the results are shown in Table 1 below.

[Experimental Example 1]

This experiment after the flexible circuit placed on a copper foil surface of the substrate 160. Figure 30 minutes a hot press with a force of 40kg _f, as shown in Fig. The coverlay film prepared in the examples and comparative examples of the present invention, two adhesive coverlay (Sample width: 1 cm, sample length: 12 cm) was measured. The angle between the sample and the adhesive force measuring instrument was 180 degrees and the speed was 50 mm / min. Respectively.

[Experimental Example 2]

In this experiment, the coverlay film prepared in Examples and Comparative Examples of the present invention was evaluated for flame retardancy in accordance with the UL-94 VTM measurement method.

[Table 1]

Evaluation items Example 1 Example 2 Example 3 Comparative Example 1 Peel strength
(N / cm) 16 11 11 9 Flammability
(VTM-0) OK OK OK OK

As can be seen from the above Table 1, it can be seen that Examples 1 to 3, in which a proper amount of the polyester resin according to the present invention was applied, had better adhesive strength than Comparative Example 1. As a result, It can be seen that the peel strength can be increased.

1 is a sectional view of a coverlay film according to an embodiment of the present invention;

2 is a schematic view of a hot press for bonding a coverlay film to a three-layer flexible circuit board according to an embodiment of the present invention

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

10: polyimide film 20: adhesive layer

30: release paper

Claims (7)

In a halogen-free coverlay adhesive composition, (a) 100 parts by weight of an epoxy resin, (b) 50 to 250 parts by weight of a carboxyl group-containing acrylonitrile butadiene rubber, (c) 10 to 100 parts by weight of a polyester resin or phosphorus-containing polyester resin having a number average molecular weight of 3,000 to 20,000, (d) 1 to 50 parts by weight of at least one curing agent selected from the group consisting of an amine type and an acid anhydride type, (e) 51 to 100 parts by weight of a phosphorus flame retardant and (f) 20 to 100 parts by weight of an inorganic flame retardant. delete delete The method according to claim 1, 61 to 100 parts by weight of the inorganic flame retardant (f). The method according to claim 1, (b) the carboxyl group-containing acrylonitrile butadiene rubber was changed to 160 parts by weight, (c) the above-mentioned polyester resin or phosphorus-containing polyester resin is 40 parts by weight, (d) the curing agent is 3 parts by weight, (e) the phosphorus flame retardant is 70 parts by weight, (f) the inorganic flame retardant is 40 parts by weight. 6. The method of claim 5, (c) the polyester resin is Vylon 220, (d) the curing agent is DDM (diaminodiphenyl methane) (e) the phosphorus flame retardant is SPB-100, (f) the halogen-free coverlay adhesive composition is characterized in that the inorganic flame retardant is H-42I. A coverlay film using the halogen-free coverlay adhesive composition according to any one of claims 1 to 6, A halogen-free coverlay adhesive composition comprising an electrically insulating substrate film, an adhesive layer coated with the halogen-free coverlay adhesive composition on the electrically insulating substrate film, and a release paper laminated on the adhesive layer. Coverage film used.

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