JPS62274690A - Flame-retardant flexible circuit substrate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a flame-retardant flexible circuit board.

[Conventional technology]

The flame-retardant flexible circuit board may contain a halogen-containing compound and an inorganic flame retardant (for example, 5b203, Aα) in the adhesive layer.
(OH)3> (e.g.,
3039) is well known.

(Problems to be solved by the invention) However, when halogen-containing compounds or inorganic flame retardants are added, although flame retardance is imparted, on the other hand, adhesion to metal foils and substrates, soldering heat resistance, chemical resistance, etc. In addition, since advanced technology is required to uniformly disperse the inorganic fuel agent into the adhesive layer, non-uniform dispersion is likely to occur.

Therefore, it has the disadvantage that there is variation in flame retardancy.

On the other hand, phosphorus compounds are well known as flame retardants for plastics, and it is conceivable that they could also be applied to flame retardant adhesives. However, even if a known phosphorus compound is added to an adhesive, flame retardancy is exhibited, but disadvantages such as low adhesive strength, poor soldering heat resistance, and poor solvent resistance may occur.

The present invention improves these problems and provides a flexible printed circuit board that has uniform and stable flame retardancy without deteriorating the physical properties required for flexible printed circuit boards, such as adhesiveness, soldering heat resistance, and chemical resistance. The purpose is to provide circuit boards.

[Means for Solving the Problems] The present invention provides a flame-retardant flexible circuit board formed by laminating a flame-retardant plastic film and a metal foil together with a flame-retardant adhesive, in which the flame-retardant adhesive comprises: A flame-retardant flexible material comprising a phosphorus compound (A>) having one or more epoxy groups in one molecule, a polyester resin (B), an epoxy resin (C), and a curing agent (D>) It relates to circuit boards.

The flame-retardant plus deck film in the present invention includes:
Examples include polyimide, polyamideimide, Teflon, polyphenylene sulfide, and general heatable films coated or coated with flame retardants, but polyimide is particularly preferred from the standpoint of heat resistance.

Copper foil, aluminum foil, and the like are known as metal foils, and copper foil is particularly preferred.

The phosphorus compound in the present invention has one or more epoxy groups in one molecule. The phosphorus content of this compound is preferably 5 wt% or more. More preferably, 8
~20wt%. If the phosphorus content is too low, it may be difficult to obtain the desired flame retardancy, and if it is too high, it may be difficult to synthesize. Moreover, the epoxy equivalent of this compound is preferably 150 to 500. More preferably, it is 250-350. If the epoxy equivalent is too small, curing tends to proceed too much and the adhesive strength decreases, while if it is too large, the adhesive strength may decrease due to insufficient curing.

Specific examples include glycidyl-α-methyl-β-di(methoxy)phosphinylpropionate H30 glycidyl-α-methyl-β-di(butoxy)phosphinylpropionate 4H90 glycidyl-α-ethyl -β-di(methoxy)phosphinylpropionate H30 and the like.

The polyester resin used in the present invention is not particularly limited, but has a melting temperature (m, p.

) is 30 to 220'C, and the glass transition temperature is 160'C.
~80°C is preferably used. Specific examples of polyester resins that can be used in the present invention include those synthesized from the following acid components and glycols. Examples of acid components include terephthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, and naphthalene-1,5-dicarboxylic acid.
-dicarboxylic acids, sebacic acid, adipic acid, maleic acid, fumaric acid, trimesic acid, trimellitic acid, pyromellitic acid, etc., and aromatic dicarboxylic acids are particularly preferred.

Glycol components include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, polytetramethylene glycol, bisphenol-ethylene oxide adduct, bisphenol A-propylene oxide adduct, etc. .

A polyester resin obtained by copolymerizing such an acid component and a glycol component can be used. Preferably, polyester resins that are soluble in common organic solvents such as acetone, methyl edyl ketone, chloroform, benzene, trichloroethylene, carbon tetrachloride are preferred. To give a more specific example, a polyester resin consisting of 40 to 60 mol% of isophthalic M as an acid component, 40 to 60 mol% of terephthalic acid, and 35 to 55 mol% of ethylene glycol and 45 to 65 mol% of neopentyl glycol as a glycol component;
Examples include polyester resins containing 55 to 75 mol% of terephthalic acid, 25 to 45 mol% of sebacic acid or adipic acid as acid components, and 30 to 50 mol% of ethylene glycol and 50 to 70 mol% of neopentyl glycol as glycol components.

Roughly 100 parts of polyethylene terephthalate, 10 to 80 parts of glycols such as diethylene glycol, triethylene glycol, polyethylene glycol, triethylene glycol, polyethylene glycol, or a mixture thereof, and further neopentyl glycol,
A polyester resin obtained by adding 5 to 40 parts of a chain-branched glycol such as an ethylene oxide adduct or a bisphenol A-propylene oxide adduct to bisphenol and transesterifying the mixture can be used.

The epoxy resin used in the present invention includes epoxy resins that do not contain halogen or epoxy resins that contain halogen, and these may be used alone or in combination.

The halogen-free epoxy used in the present invention may be any epoxy resin as long as it has two or more epoxy groups in one molecule, but suitable examples include novolac type epoxy resin, dimer acid type epoxy resin, etc. There are epoxy resins, polyglycol type epoxy resins, etc.

The halogen-containing epoxy resin used in the present invention may be any resin as long as it has an epoxy group and a halogen atom in one molecule, but preferred examples include bisphenol-type brominated epoxy resin, novolac-type brominated epoxy resin, etc. Examples include epoxy resins and ether-type brominated epoxy resins. Specifically, "Epicote 1050" manufactured by Shell Chemical Co., Ltd., "'DER" manufactured by Dow Chemical Co., Ltd.
542”, “BRE N-S” manufactured by Nippon Koyaku Co., Ltd.
"and so on.

If it is desired to further improve flame retardancy, it is effective to use a halogen-containing epoxy resin as the epoxy resin, or to use a combination of a halogen-containing epoxy resin and a halogen-free epoxy resin.

In this case, it is preferable to use 30 to 3 Qwt% of the halogen-containing epoxy resin among all the epoxy resins. When the halogen-containing epoxy resin exceeds aowtχ, the adhesive strength tends to decrease. Moreover, if it is less than 30 wt%, there may be no effect of improving flame retardancy.

Examples of the curing agent used in the present invention include known epoxy resin curing agents such as amines, acid anhydrides, and imidazoles, but acid anhydrides are preferred from the viewpoint of heat resistance.

Although the amounts of the components of the adhesive composition used in the present invention are not particularly limited, they are preferably used in the following proportions.

That is, it is preferable to mix 150 to 350 parts of the polyester resin, more preferably 200 to 300 parts, to 100 parts (parts by weight; see below) of the phosphorus compound having an epoxy group. If the amount of polyester resin is too small, the adhesive strength may be reduced, and if it is too large, the flame retardance may be reduced.

The epoxy resin should be blended in an amount of 100 to 300 parts.

The amount is preferably 150 to 250 parts.

If the amount of epoxy resin is too small, the adhesive strength may be reduced, and if it is too large, the flame retardancy may be reduced. The curing agent is 10 to 60
parts, preferably 30 to 40 parts. If there is too little curing agent, the epoxy resin will not harden and the adhesive strength will tend to decrease. If the amount is too high, curing may progress too much and adhesive strength may decrease.

Further, other components may be added to the extent that adhesive strength and flame retardant properties are not deteriorated. Examples include acrylic resins and acrylonitrile-butadiene' (7).
'N1! E'r fat, 5b203, 80, (oH)
Examples include inorganic particles such as No. 3.

Next, a method for manufacturing the flame-retardant adhesive used in the present invention will be explained. First, a predetermined amount of an organic solvent is added to and dissolved in a predetermined amount of a phosphorus compound having an epoxy group. Subsequently, predetermined amounts of polyester resin, epoxy resin, and curing agent are added and dissolved to obtain a flame-retardant adhesive composition.

Next, a flame-retardant flexible circuit board is manufactured using this adhesive. That is, it is manufactured by applying a flame-retardant adhesive onto a flame-retardant film using a roll method or the like, drying it, and then laminating it with metal foil.

The thus obtained flame-retardant flexible circuit board of the present invention can be used as a material for a flexible wiring board manufactured through a photolithography process.

[Method for Measuring Characteristics and Evaluating Effects] Methods for measuring characteristic values and evaluating effects of the present invention are as follows.

Adhesive Crab The force required to peel off the copper foil in the 90' direction from the surface of the substrate at a speed of 50 mm/min was measured.

Practically speaking, an adhesive force of about 1 (kJ/cm) or more is required.

Soldering heat resistance: The quality of the appearance after floating the sample in a 300° C. solder bath for 30 seconds was judged.

Those with no change in appearance are better.

Solvent resistance: A 2 On+m square sample was immersed in methylene chloride for 15 minutes at room temperature, and then the penetration distance of methylene chloride was measured.

The smaller the penetration distance, the better.

Flame retardancy: A combustion test was conducted in accordance with the tJL-94 standard. The UL-94 standard defines flame retardancy as V-O, V-LV-2,
They are ranked into four categories: HB, with ■-〇 being the most excellent in flame retardancy. Next is V-LV-2 and then HB.

Those inferior to HB were evaluated as having no flame retardancy.

〔Example〕

Example 1 To 100 parts of glycidyl-α-medyru-β-di(butoxy)phosphinylpropionate [manufactured by Ohe Kagaku Co., Ltd.],
500 parts of methyl ethyl ketone was added and dissolved. Roughly 250 parts of "Vylon 300" (polyester resin) [Toyobo Co., Ltd.] and "BREN-3" (
100 parts of brominated epoxy resin) (manufactured by Nippon Koyaku Co., Ltd.) and 120 parts of "Epicote 152" epoxy resin) (produced by Shell Kagaku Co., Ltd.) were dissolved. 30 parts of phthalic anhydride (ILP-forming agent) was added to the colander and stirred well.

The adhesive has a concentration of 54.5 wt% and a viscosity of 3.5 (PS/
25°C).

Next, this adhesive solution was applied onto a polyimide film having a thickness of 25 μm so that the coating thickness of dried wheat was 15 to 40 μm. Thereafter, it was heated and dried at 80°C for 2 minutes. Next, a 35μ thick copper foil was laminated on top of the 120μ thick copper foil.
'Cl2kCJ/Cm, roll laminated at a speed of 1 m/min and heated at 150'C in the recuperating air oven for 50 minutes.
After time curing, a flexible circuit board was obtained. Characteristic values are shown in the table.

Example 2 500 parts of dimethylformamide was added to 100 parts of glycidyl-α-medy-β-di(butoxy)phosphinylpropionate and dissolved therein.

200 parts of Zarani "Pain 200" (polyester resin) [manufactured by Toyobo Co., Ltd.] and 120 parts of "D E R542" (brominated epoxy resin) [manufactured by Dow Chemical Co., Ltd.]
and 130 parts of "Epicote 871" (epoxy resin) [manufactured by Shell Chemical Co., Ltd.] were added and dissolved. 30 parts of phthalic anhydride (hardening agent) was added to the colander and stirred well.

The adhesive has 4 concentrations.

The content was 0 wt%, and the viscosity was 4.2 (PS/25°C).

Using this, a flexible circuit board was made in the same manner as in Example 1. Characteristic values are shown in the table.

Comparative Example 1 250 parts of “Byron 300” and “BRE N-S”
500 parts of methyl ethyl ketone was added to 250 parts of "Epicote 152" and 120 parts of "Epicote 152" and dissolved therein.

To this was added 30 parts of phthalic anhydride, and the mixture was thoroughly stirred.

The adhesive has a concentration of 54.5 wt% and a viscosity of 2.7 (PS/
25°C). Characteristic values are shown in the table. It did not have flame retardancy that met the UL standard. Since it contained a large amount of brominated epoxy, its adhesive strength was as low as 0.2 kq/cm.

Comparative Example 2 Triphenylphosphate (phosphorus compound>100 parts, 5
00 parts of methyl ethyl ketone was added and dissolved. 250 copies of Zarani “Byron 300” and “BREN-3”
100 parts and 120 parts of "Epikote 152" were added and dissolved. Furthermore, 30 parts of phthalic anhydride was added and stirred well. The adhesive had a concentration of 54.5 wt% and a viscosity of 3.0 (
PS/25°C). Since a phosphorus compound having no epoxy group was added, the flame retardance was VO, but the soldering heat resistance was poor. The adhesive strength was also insufficient.

(Effects of the Invention) The present invention relates to a flame-retardant flexible circuit board, and has the following excellent effects.

(1) It was possible to satisfy the mechanical properties required for a flexible circuit board and to provide a high degree of flame retardancy.

(2) Since no inorganic flame retardant is used in the adhesive layer,
The process was simplified and excellent properties were obtained.

Claims (3)

[Claims] (1) In a flame-retardant flexible circuit board formed by laminating a flame-retardant plastic film and a metal foil with a flame-retardant adhesive, the flame-retardant adhesive contains one or more epoxy groups in one molecule. A flame-retardant flexible circuit board comprising a phosphorus compound (A), a polyester resin (B), an epoxy resin (C), and a curing agent (D). (2) The flame-retardant flexible circuit board according to claim (1), wherein the epoxy resin (C) is a halogen-containing epoxy resin. (3) The flame-retardant flexible circuit board according to claim (1), wherein the epoxy resin (C) is composed of a halogen-containing epoxy resin and a halogen-free epoxy resin.