JPS60129253A - Manufacture of flexible printed 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 The present invention relates to a flexible printed circuit board (hereinafter referred to as rFP).
Regarding the manufacturing method of CJ (abbreviated as CJ), we provide FPC with miscellaneous reinforcement base, which has excellent bendability, solder heat resistance, and chemical resistance.

FPCs containing a reinforcing base material are known, and epoxy resin is mainly used as the material for the board.

The reason for this is that epoxy resins have excellent heat resistance, chemical resistance, and electrical properties.

The conventional FPC'IlJ manufacturing method using epoxy resin is as follows:
First, an epoxy resin sheet containing reinforcing group I is made, a metal foil is pasted onto this using an adhesive, the solvent is removed by heating and drying, and the metal foil is bonded. Another method is to impregnate the reinforcing base material with epoxy resin, evaporate the solvent, heat it to pre-cure it, then overlap it with metal foil, press it, and integrate it by heating and pressing. .

Both of these conventional methods involve complicated steps.

This is because the epoxy resin does not harden quickly. In conventional FPCs containing reinforcing base materials, if the degree of polymerization is increased or an inorganic reinforcing material is added in an attempt to improve heat resistance, the sinterability is impaired and the suitability for bending is reduced.

Although FPCs containing reinforcing base materials are lower in cost than film-based products using polyimide, it is generally accepted that they are inferior in flexibility.

The present inventors have developed an F material containing reinforced base material with high flexibility.
We conducted research with the intention of manufacturing PC using a simple method, and succeeded in simplifying the process by using an electron beam curing method and improving flexibility by selecting materials, resulting in the present invention.

The method for producing FPc (7) of the present invention is as follows A), t3)
Impregnating a mechanical fibrous material with an electron beam curable composition consisting of two components, A) Synthesizing from an organic polyisocyanate, a polyhydroxy polyether, and an acrylate having at least one free hydroxy group or carboxyl in one molecule. and B) an acrylate monomer having a group selected from carboxyl, aziridinyl, phosphoric acid and hydroxyl groups, and then irradiating with an electron beam.

The manufacturing process is simplified by the above method because the curing of the resin is much faster than that of conventional epoxy resins due to the use of the high energy of electron beams, which requires preliminary curing in an oven and subsequent pressing. This is called main curing by
This is because there is no need to go through two steps.

The above urethane acrylate A used in the present invention
) is composed of 2 to 3 polyisocyanes in the molecule.
It is an aliphatic or aromatic polyisocyanate having 2 incyanate groups.

Specifically, tetramethylene diisocyanate, hexamethylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4
．． 4-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, 3,3'-dimethyl-4,
4--Diphenylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, 1.3-
Bis(incyanatomethyl)cyclohexane, trimethylhexamethylene diisocyanate, triphenylmethane triisocyanate-1~, and 0CN-(CH2)
Examples include e-N-[C0NH(CH2)eNCO]2. Of course, these polyisocyanates may be used in combination.

Human oxy group-containing polyethers include polyethers obtained by polymerization or copolymerization of ethylene oxide, propylene oxide, detrahydride [1-furan, etc.], as well as trimethyl [1-propane, glycerin, hexanetriol, pentaerythritol, There are polyethers which are produced by reacting a compound containing an active hydrogen atom as a hydroxy group or a mercapto group, such as ethylene thioglycol or but[]pyrene glycol, with a cyclic ether such as the above-mentioned ethylene oxide.

Specific examples of acrylates having at least one free hydroxy or carboxyl group in one molecule include hydroxyethyl acrylate-1-, hydroxyethyl acrylate, human 0xybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate,
Hydroxybutyl methacrylate, 4-hydroxycyclohexyl acrylate, 5-hydro=1-dicyclooctyl acrylate, 5-human 0oxycyclooctyl methacrylate, 2-hydroxy-3-phenyloxypropyl acrylate, acrylic acid, methacrylic acid, 2 −
It is an adduct of hydroxyethyl acrylate and phthalic anhydride. Furthermore, ethylene glycol diglycidyl ether dimethacrylate, diethylene glycol diglycidyl ether dimethacrylate, propylene glycol diglycidyl ether diacrylate,
Also useful are zero-addition products of jepoxy compounds and acrylic acid, such as phthalic acid diglycidyl ester diacrylate, or products of glycidyl acrylate, glycidyl methacrylate, and dibasic acids. Dibasic acids include itaconic acid, maleic acid, fumaric acid, succinic acid,
Adipic acid and phthalic acid are representative.

Typical tI structures of urethane acrylate obtained by reacting the above-mentioned components are the following three types, and each can be formed as follows.

(1) Structure having acrylic groups at both ends of a linear compound: Reacting excess isocyanate with hydroxyl group-containing polyether to form incyanate at both ends. A prepolymer is prepared, and then both ends are reacted with an acrylate containing hydroxy or carboxyl groups.

(2) Adding an acrylic group to the chain end (3 or more locations) of a branched compound 4f4'l=M...
...A prepolymer containing isocyanate at both ends is created by reacting excess isocyanate with hydroxy group-containing polyether, and then reacting with droxy group- or carboxyl group-containing acrylate at one end. A prepolymer of acrylic at one end and isocyanate at one end is obtained.

By further reacting with trihydroxypolyether, branched urethane acrylate-1 is obtained.

(3) Adding an acrylic group to the side chain of the compound (lfa) For the hydroxy group-containing polyether and the dihydroxy cloud-containing acrylate-1, an excess of isocyanate relative to the equivalent amount of both hydroxy groups is added. A prepolymer having isocyanate at both terminals is prepared by reacting the two. Then, acrylate-1- having a hydroxy group or carboxyl group is reacted with urethane acrylate having an acrylic group in the side chain and both ends.

The reaction between a hydroxy group or a carboxyl group and an isocyanate group can be carried out by a known method.
That is, an active hydrogen atom-containing compound and an isocyanate group-containing compound may be mixed and heated to 40 to 100°C. Although the reaction can be carried out without a solvent, it may also be carried out in an inert solvent or in a monomer active to electron beams. To accelerate the reaction, triethylamine, piperazine, triethanolamine, dibutyltin dilaure-1, stannas octoate-1, stannas laurate, dioctyltin dilaure-1, etc. can be used.

In order to prevent the acrylic group from polymerizing during the reaction, it is desirable to add an appropriate amount of a polymerization inhibitor, for example, 10 to 11,000 pp. Examples of polymerization inhibitors include hydroquinone, hydroquinone monometyl, benzoquinone,
Examples include 2.6-di(-butyl-1)-cresol.

The above method for producing urethane acrylate is not limited, and various other embodiments are possible.

In the present invention, electron beam curable acrylate 1 and 7-mer 0) are blended with the above components. B)
As mentioned above, the component has a functional group such as a carboxyl group, an aziridinyl group, a phosphoric acid group, a hydroxyl group, etc. Specific examples include acrylic acid, 2-acryloyl, etc. There are 1=1 adducts of acid anhydrides and acrylates containing hydroxy or amine groups, such as ethyl succinate, 2-hydroxyethyl acrylate and maleic anhydride adducts, and phthalic anhydride adducts such as acrylamide. .
Those having an aziridinyl group include 2-(1-aziridinyl) ethyl acrylate and 2-(1-aziridinyl) ethyl methacrylate, and those having phosphorus II include 2-acryloyloxyethylamide phosphate. , 2-metaglycoyloxyethylamide phosphate, diphenyl-2-methacryloyloxyethyl phosphate, and dibdel-2-acryloyloxyethyl phosphate. As those having a hydroxy group, those similar to those mentioned above regarding component A) can be used, such as 2-hydroxyethyl acrylate, 2-hydroxyethyl acrylate,
-Hydroxyethyl methacrylate, 2-human axy-
3-phenyl A-xypropyl acrylate is a typical example, and 1:1 adducts of acrylates having a hydroxyl group and polypolymer compounds are also useful.

It is preferable to add a reactive diluent to a composition consisting of component A) and component B), since this increases coating suitability. Reactive diluent compounds have an ethylenically unsaturated bond in the molecule, and specifically refer to the following compounds: -, J-, -J-, i.e., ethylene , α, -Methyl”-styrene threads such as tyrene, methyl acrylate, M-2-ethylhexyl acrylate, methoxyethyl acrylate, butoxyethyl acrylate, butyl acrylate, methoxybutyl acrylate, phenyl acrylate Acrylic esters such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, methacrylate:1-diethyl,
Ethoxyethyl methacrylate, phenyl methacrylate,
Methacrylic acid esters such as lauryl methacrylate, acrylamide, unsaturated carboxylic acid amides such as methacrylamide, acrylic! Iu-2-(N,N=-dimethylamino)ethyl, methacrylic acid-2-(N,N-
-dimethylamino)ethyl, acrylic acid-2-(N,N
--dibenzylamino)ethyl, methacrylic acid-2-(
N,N--dimethylamino)methyl, acrylic M-2-
Substituted amino alcohol esters of unsaturated acids such as (N,N'-diethylamino)propyl, N-methylcarbamoyloxyethyl acrylate, N-1 dicarbamoyloxyethyl acrylate, N-butylcarbamoyloxyethyl acrylate , N-phenylcarbamoyloxyethyl acrylate, 2-(N-methylcarbamoyloxy)edyl acrylate, carbamoyloxyalkyl acrylates such as 2-carbamoyloxypropyl acrylate, ethylene glycol diacrylate,
Neopentyl glycol diacrylate, 1,6-hexanediA-diacrylate-1-, diethylene glycol diacrylate, triethylene glycol diacrylate, dipropylene glycol diacrylate, ethylene glycol dimethacrylate-1~, propylene glycol dimethacrylate, diethylene glycol diacrylate Diacrylates or dimethacrylates such as methacrylate. Of course, two or more of these reactive diluting agents can be used in combination.

A reinforcing fibrous floor material I is impregnated with a resin composition consisting of each of the above components. The base material can be either an organic fiber type or an inorganic fiber type, and both have a high reinforcing effect, but the former is preferable in terms of bendability, and the latter is effective in terms of heat resistance.

Therefore, depending on the characteristics required for the product FPC, it is preferable to use organic fibers alone or in combination with an appropriate amount of inorganic fibers, for example, as a laminated layer. Organic fibers include aromatic polyamide,
Non-woven fibers or cloths mainly made of heat-resistant fibers such as aromatic polyamide polyimide are suitable, and IN-free II fibers, glass fibers, carbon fibers, and boron nitride fibers are preferred.

Impregnation of the resin composition into the fibrous base material can be carried out according to known techniques. For example, an impregnating device equipped with an impregnating head and a squeegee metal roller or doctor, a roll coater, a pot-melt coater, or the like is used.

The metal foil used for FPC is not particularly limited, but copper foil is generally used in consideration of conductivity and rust prevention, and aluminum foil can also be used.

The electron beam for curing the resin is supplied from various types of electron beam accelerators, including Cockroft-Wald type, Bumpgraph type, resonant transformer type, insulated core transformer type, linear type, Dynamidron type, and high frequency type. Energy is 50-100OKe
(2) An electron beam in the range of preferably 100 to 300 KeV is suitable, and the radiation intensity is 1 to 20 M rad. 1
If Mrac is less than 1, curing is generally insufficient. 20
An amount exceeding Mrad is unnecessary, and an amount exceeding 60 Mrad will cause decomposition and deteriorate the physical properties of the cured resin.

Electron beam irradiation is carried out by running a base material impregnated with horse chestnut liquid and layered with metal foil, and applying a curtain-shaped electron beam emitted from a linear filament, usually from the side without the metal foil. , continuously.

However, irradiation is also possible from the side with the metal foil, if the base material is thick (tl), and if the metal foil is dried on both sides,
The irradiation will penetrate through the metal foil.

The method of the present invention utilizes the high energy of electron beams to harden the resin at an extremely high speed, thereby eliminating the need for pre-curing in an oven, followed by main curing in a press, unlike the prior art. FPC in a short time without going through troublesome processes! JI! I can build it.

The FPC manufactured by the method of the present invention exhibits high flexibility and heat resistance. One reason for this is that the resin used is mainly composed of urethane polymer, and the strong intermolecular force of the urethane group increases the toughness of the resin by 1.7%. Another reason is that by providing electron beam curability, it is possible to selectively control the degree of crosslinking between urethane polymers, the level of acrylate, and the amount of electron beam heat, thereby increasing flexibility and heat resistance in a well-balanced manner. It is.

Since the resin itself has high heat resistance, it is not necessary to use an inorganic material as the h11 strong base material, and only an organic material is sufficient, which is advantageous for improving flexibility. 1. If the emphasis is on mechanical strength, it is better to use inorganic fibers layered on organic fibers.

The present invention will be specifically described below with reference to reference examples ("manufacture of urethane acrylate") and examples.

Reference Example 1 752 g of xylylene diisocyanate and 1 g of dibutyl dilaurate were charged into a four-eye flask equipped with a stirrer, a hygrometer, a condenser J3, and a dropping funnel, and the mixture was heated to 350°C. While heating, 600 g of polyethylene glycol (molecular ffi 200) was added dropwise.
A prepolymer with terminal isocyanate-I was synthesized.

While maintaining the temperature of this reaction mixture at 50° C., 230 g of hydroxyethyl acrylate was added dropwise, and after completion of the dropwise addition, 2.0 g of hydroquinone was stirred at 50° C. for 3 hours to obtain urethane acrylate.

Xylylene diisocyanate t1 was added to the same device as Moxibustion
500 (Iil'i and dibutylzuzu dilaure t-1
, 1 g was charged, heated to 35° C., and polyethylene glycol (molecule ff1200>12009) was added dropwise to synthesize prepoly7-, which has isocyanate at both terminals.

Hydroxyethyl acrylate-1-219 (
+ was dried dropwise at a reaction temperature of 35°C to form a prepolymer 1E with isocyanate at one end and acrylic at one end.

Furthermore, 450c+ of poly=1-ethylene glycol triol (molecular weight 3000) was added dropwise to this reaction product at a reaction temperature of 50°C. After completion of dripping, add hydroquinone 1
．． 3 g was added, and the reaction temperature was kept at 50°C for another 3
Continuing the reaction for 48 hours, C1 trifunctional urethane acrylate was added to 48/ζ.

14 Xylylene diisocyanate 10 in the same equipment as Reference Example 1
30 (+) and dibutyl dilaure-1-1.2 g were charged, heated to 35°C, and 2000 g of polyethylene glycol (Makurabu 400) and ethylene glycol diglycidyl ether diacrylate-1-80 (+) were added dropwise. A terminal isocyanate prepolymer having an acrylic group in the side chain was synthesized.

To this product, 110 g of human O-oxyethyl acrylate was added dropwise at a temperature of 55° C. After the addition, 2.1 g of hydroquinone was added and the reaction was continued for a further 3 hours to obtain urethane acrylate.

Part 1i1 A resin liquid having the following composition was heated to 80°C to lower the viscosity, and the urethane acrylate of Reference Example 1 755 parts N-carbamoylbutyl oxyacrylate 25 parts N-acryloyl ethyl succinate 5 parts aromatic polyamide heat-resistant nonwoven fabric (DuPont Far East, 8
5μ).

Layer copper foil (35μ) on top of this, and from the opposite side of the copper foil,
Electron beam irradiation device (ESIS-Electro Curtain CB2
Using FPCel! J.

5.0 parts of urethane acrylate of Reference Example 2 25 parts of tetraethylene glycol diacrylate 25 parts of 2-hydroxy-3-phenyloxypropyl acrylate 25 parts of heat-resistant nonwoven fabric (the above ) - Glass cloth (Nittobo, WEO5
D) The two-layer reinforced base material was impregnated.

Then, copper foil was layered on top of the other, and an FPC was obtained in the same manner as in Example 1.

A resin liquid having the following composition was added to the resin solution of Reference Example 3: 700 parts N-carbamoyloxytylac, rylate 25 parts 2-acryloyl ethyl sakune sheet 5 parts Heat-resistant non-woven fabric - Glass cloth - Heat-resistant non-woven fabric (both It was also impregnated into a three-layer reinforcing base material (as described above).

An FPC was obtained in the same manner as in Example 1 below.

Superintendent 1 Epoxy resin liquid with the following composition (Shell Chemical) Epicoat 828 100 parts D D 8. A glass cloth was impregnated with 90 parts of 20 parts of BF3-400 and 1 part of methyl ethyl ketone, and the solvent was evaporated in an oven to obtain a prepreg.

This prepreg was layered with copper foil and pressed at 160°C for 15 minutes with a contact pressure of 600 psi to form FPC'4! −
Obtained.

Test Jl Presentation - In Examples 1 to 3 and Comparative Examples (1:PC for each of q)
A bending test was conducted for this. Using an MIT tester, the base material from which the copper foil was peeled was used as a test piece, and the test piece was repeatedly bent under the following conditions, and the number of times the test piece was bent until it broke was measured.

Radius of curvature 0.38111m Load weight 1Kg Bending speed: 175 times/vin The results are shown below along with the thickness of the test piece.

Trial IUL
0 μ 1000 times or more Example 2 150 μ Approx. 800 times Example 3 200 μ Approx. 900 times Comparative example 100 μ 20 times Patent applicant Dai Nippon Printing Co., Ltd. Agent Patent attorney Souo Suga

Claims (3)

[Claims] (1) A fibrous substrate is impregnated with an electron beam curable composition consisting of the following △>, B) two components, A) organic polyisocyanate, polyhydroxy polyether, and 1if.
Urethane acrylate synthesized from acrylate-I- having at least one hydroxyl group or carboxyl in one molecule, and B) a group selected from a carboxyl group, an aziridinyl group, a phosphoric acid group, and a hydroxyl group. Acrylate/Nanatsumar - Flexible print made by pasting metal foils together and then irradiating them with electron beams (1) Production of circuit boards. (2) The manufacturing method according to claim 1, in which organic fiber fabric or nonwoven fabric is used as the fibrous substrate. (3) The manufacturing method according to claim 1, in which a laminate of woven or nonwoven fabrics of organic fibers and inorganic fibers is used as the fibrous material.