JPS63218757A - Heat-resistant film - Google Patents

Abstract

PURPOSE:To obtain a heat-resistant film having self-supporting properties, suitable in flexible print circuit boards, comprising a reaction product containing a specific saturated polyester resin and maleimide resin and/or a modified maleimide resin. CONSTITUTION:(A) 85-40wt.% saturated polyester resin containing >=20mol.%, preferably >=30mol.% based on the polymer of an alkylene terephthalate (preferably ethylene terephthalate) repeating unit and (B) 15-60wt.% maleimide resin (reaction product of a bismaleimide and diamine) and/or maleimide modified resin (resin comprising a bismaleimide and a triazine resin as main components) are blended with a curing gent (e.g. epoxy resin) and a curing catalyst, diluted with a solvent in such a way that sum of the resin solid contents of the components A and B is 5-80wt.%, applied to a resin film, etc., dried and cured to give a film.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to heat resistant films, and more particularly to improved heat resistant self-supporting films suitable for use in flexible printed circuit boards. Regarding the film that was made.

(Prior Art) In recent years, so-called flexible printed circuit boards have been widely used in the electronics field, contributing to the miniaturization and weight reduction of equipment. Flexible printed circuit boards are produced by adhesively laminating copper foil onto a synthetic resin film substrate to form a copper-clad laminate sheet, forming a circuit pattern on the surface of the copper foil by screen printing or photoresist, and then etching the copper by wet etching. A copper circuit is formed by removing unnecessary parts of the foil. Synthetic resin films used for this purpose include polyester films, polyimide films, glass cloth-reinforced epoxy resin sheets, and aramid paper, which are important because of their electrical insulation, heat resistance, chemical resistance, and mechanical suitability. There is.

However, when used as a substrate film or coverlay film for flexible printed circuit boards, for example, 26
It must withstand soldering baths at 0° C. or higher, manual soldering at 350° C. or higher, and heat-pressure changes.Currently used polyester films, although inexpensive, do not have such soldering heat resistance.

(Problems to be Solved by the Invention) The present invention provides a solder bath at 260°C or higher, which is based on a polyester component, and which is suitable for use in flexible printed circuit boards, which is not found in conventional polyester films.
The present invention aims to provide a heat-resistant film that can withstand the above-described manual soldering and thermocompression bonding.

(Means for Solving the Problems) As a result of intensive research to solve the above-mentioned problems of conventional polyester films, the present inventors have found that they have a high degree of heat resistance, that is, a solder bath of 260° C. or higher; The present invention has been achieved by discovering a self-supporting heat-resistant film suitable for use in flexible printed circuit boards and coverlay films that can withstand manual soldering and heat pressure at temperatures of 350° C. or higher. That is,
The present invention provides a saturated polyester resin (a) containing at least 20 mol% of alkylene terephthalate repeating units,
Maleimide resin and/or maleimide modified resin (b) and (a) 85 to 40 weight 11 to the total resin composition, respectively.
%, (b) a reaction product containing 15 to 60 Tn amount %.

The saturated polyester resin containing at least 20 mol % of alkylene terephthalate repeating units based on the polymer used in the present invention means that the acid component is 1. A saturated polyester resin in which the proportion of alkylene terephthalate repeating units in a saturated polyester resin (1 mole) consisting of a total of 1.0 mole and a glycol component is 30 mole% or more when expressed in il%. It is. Specifically, 0.6 mol of terephthalic acid units, 0.6 mol of inphthalic acid units.
The alkylene terephthalate units of a polyester consisting of 4 moles, 0.7 moles of ethylene glycol units, and 0.3 moles of neopentyl glycol units are 0.8X0.7+0
．． 6X0.3-0.8, which means 60 mol%.
Become.

Acid components other than terephthalic acid that form the polyester of the present invention include, for example, isophthalic acid, phthalic acid, aromatic dicarboxylic acids such as naphthalene dicarboxylic acid, succinic acid, adipic acid, azelaic acid, cepatic acid, dodecanedio/acid, and dimer acid. There are aliphatic dicarboxylic acids such as In the form of glycol, the alkylene/glycol forming the polyester of the present invention includes ethylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, diethylene glycol, triethylene glycol, 2.2
- Glycols containing an ether bond, such as ethylene glycol ether of bis(hydroxyphenyl)propane, are also included as alkylene glycols.

Hydroxy compounds other than alkylene glycol that form the polyester of the present invention include hydroquinone, resorcinol, 2-2 bis(hydroxyphenyl)propane, and the like. Further, the saturated polyester resin used in the present invention may contain polyfunctional units such as trimellitic acid units, pyromellitic acid units, trimethylolpropane units, and pentaerythritol units.

The polyester used in the present invention is a saturated polyester resin containing at least 20 mol% or more, preferably 30 mol% or more of alkylene terephthalate repeating units. Particularly preferably the alkylene terephthalate units are
It is an ethylene terephthalate unit. If the alkylene terephthalate unit is less than 20 mol%, the cured adhesive layer will have poor solvent resistance, which is disadvantageous. The opening viscosity of the polyester resin of the present invention is preferably 0.2 to 1.5 dl/g at 30°C as a mixed solution of phenol/1,1.2-tetrachloroethane-60/40 (ffI ratio). is 0
．． It is 4 to 0.7 dl/g. The use of a mixture of two or more types of polyester resins is one of the preferred embodiments of the present invention.

The maleimide resin used in the present invention is a reaction product of bismaleimides and a diamine compound, and examples of the bismaleimides include N,N'-ethylene bismaleimide,
N,N'-hexamethylene bismaleimide, N,N'-
m-phenylene bismaleimide, N,N'-p-phenylene bismaleimide, N,N'-4,4'-diphenylmethane bismaleimide, N,N'-4,4'-diphenyl ether bismaleimide, N,N'- 4,4'-diphenylsul7one bismaleimide, N,N'-4,4'
-dicyclohexylmethane bismaleimide, N, N'-
α.

α'-4,4'-dimethylenecyclohexane bismaleimide, N, N'-m-methaxylene bismaleimide, N
, N'-4,4'-diphenylcyclohexane bismaleimide, etc., and examples of the diamine compound include 4.4
'-Diaminodicyclohexylmethane, 1,4-diaminocyclohexane, 2,6-diamitupyridine, m-phenylenediamine, p-7enylenediamine 7.4.4'
-diaminodiphenylmethane, 2,2'-bis(4-aminophenyl)furopane, benzidine, 4,4'-diaminophenyl oxide, 4,4'-diaminodiphenylsulfone, bis(4-aminophenyl)methylphosphine/oxide, bis (4-aminophenyl)phenylphosphine oxyto, bis(4-7minophenyl)methylamine, 1.5-diaminonaphthalene, m-xylylenediamine, 1.1-bis(p-aminophenyl) flag 7
, p-xylylene diamine, hexamethylene diamine,
e, e'-diamine-2,2'-cuviridine, 4.4'
-diaminobenzophenone, 4,4'-diaminoazobenzene, bis(4-aminophenyl)phenylmethane,
1.1-bis(4-7minophenyl)cyclohexane,
1. l-bis(4-amino-8-methylphenyl)cyclohexane, 2,5-(m-aminophenyl)-1,3
, 4-oxadiazole, 2.5-bis(p-aminophenyl)-1,3,4-oxadiazole, 2.5-bis(m-aminophenyl)thiazolo(4,5-d)thiazole, 5.5'-di(m-aminophenyl)-(2,
2')-bis(1,3,4-oxadiazole), 4.4
'-Diaminodiphenyl ether, 4,4'-bis(p
-aminophenyl)-2,2'-dithiazole, m-bis(4-p-aminophenyl-2-thiazolyl)benzene, 4,4'-diaminobenzanilide, 4,4'-diaminophenylbenzoate, N, N'-bis(4-7
minobenzyl)-p-phenylenediamine, 4.4'-
Examples include methylenebis(2-chloroaniline).

In addition, the maleimide-modified resin as used in the present invention refers to a highly heat-resistant addition heavy metal type thermosetting resin containing an imide group in the molecule, which is mainly composed of two components: bismaleimide and triazine resin.
Alternatively, it is a thermosetting resin in which a bismaleimide nieboxyl compound is combined. Specific examples of the resin include B
Examples include T-resin (trade name of Mitsubishi Gas Chemical Co., Ltd.) and imidaloyl (trade name of Toshiba Chemical Co., Ltd.).

The mixing weight ratio of the saturated polyester resin (a), maleimide resin and/or maleimide modified resin 11M (b) of the present invention is 85 to 40% by weight of (a) to the total resin composition, (
b) 15-60% by weight. Saturated polyester resin (
When a) is more than 85% by weight, heat resistance decreases, which is not preferable. On the other hand, if the amount is less than 40% by weight, the film becomes hard (and flexibility decreases, which is undesirable). If the amount of maleimide resin and/or maleimide-modified resin (b) is more than 60% by weight, heat resistance improves, but the film becomes hard. Flexibility decreases, which is undesirable. On the other hand, if it is less than 15111ffi%, heat resistance decreases, which is undesirable.

In the present invention, an epoxy resin and/or the same modified resin may be added as a curing agent to the components.

The epoxy resin in the present invention has at least two
Any epoxy resin can be used as long as it forms 3 or more epoxy groups, but suitable examples include bis7'enol type epoxy resin and its halogenated product, glycidyl ether type such as novolac type epoxy resin,
Alternatively, there are ester types such as aromatic epoxy resins and cycloaliphatic epoxy resins, glycidyl ester types, and glycidyl amine types. Particularly preferred are bisphenol A type and novolac type epoxy resins.

In addition, epoxy modified resin is a compound that reacts with an epoxy resin in advance with a compound that reacts with an epoxy ring, and typical examples include a reaction product of an epoxy resin and a phenol resin,
There are reaction products of epoxy resin and amine compound, reaction products of epoxy resin and acrylic acid, etc.

In the present invention, the saturated polyester resin and maleimide resin or maleimide-modified resin are cured not only by heating but also by ultraviolet irradiation and electron beam irradiation, and the cured product has heat resistance (solder resistance). ), has excellent properties such as chemical resistance, and electrical insulation properties, and these characteristics are useful in determining the required performance as a heat-resistant film suitable for printed circuit boards. There is.

In the present invention, when curing by heating, a curing catalyst may be added to promote the curing reaction. Examples of the curing catalyst include triethylenediamine, N,N'-dimethylbenzylamine, and N-methylmorpholine. , tri-n-butylamine, N.

Tertiary amines such as N,N',N'-tetramethylbutanediamine, 2-methylimidazole, 2-andecylimidazole, 2-7 enylimidazole, 2
- Imidazoles such as ethyl 4-methylimidazole, 0' metal salts such as zinc octylate, zinc octylate such as tin octylate, metal naphthenates such as cobalt naphthenate, acetylacetone gold such as iron acetylacetone and copper acetylacetone. Printing salt, metal stearate, butyl titanate, propyl aluminum, etc., as well as tetrachloride, dicumyl peroxide, be/noyl peroxide, t-butyl hydroperoxide, cyclohexanone peroxide, decanoyl peroxide, diimpropyl peroxide, etc. Examples include peroxide peroxide such as oxydicarbonate, and metal powders such as iron and zinc, which may be used alone or in combination of two or more.

The resin composition of the present invention can be used in a synthetic resin film (or sheet) or gold li! diluted with a solvent. Coated on I foil. It is diluted with a solvent so that the total amount of resin solids consisting of saturated polyester resin (&), maleimide resin and/or maleimide modified resin (b) becomes 5 to aoim%.

Solvents used in the present invention include ketones such as methyl ethyl ketone, methyl imbutyl ketone, and cyclohexane, esters such as ethyl acetate and butyl acetate, esters such as toluene and xylene, hydrocarbons such as toluene and xylene, methylene chloride, 1,1.1-) Halogenated hydrocarbons such as lychloroethane, ethers such as dioxane and tetrahydrofuran, nitrated hydrocarbons such as nitroethane and nitromethane, and ether esters such as cellosolve acetate are used, but in particular Not limited. These solvents can be used alone or in combination of two or more. Coating on the synthetic resin film (or sheet) or metal track can be done by conventional dip, spray, gravure coating, roll coating, etc. Coat thickness is usually 1-200μ
m1 is preferably 10 to 100 μm, the coating is dried and the solvent is removed, and the drying temperature is room temperature to 160 ° C.
Preferably the temperature is 50 to 120°C, and the time is several seconds to 15 minutes, preferably 10 to 60 seconds.

After drying, a curing reaction is preferably carried out at room temperature to 50° C. and 30 to 90% R1+ after seasoning, but is not limited thereto. Curing conditions are 120-160℃ for a few seconds.
Several minutes, preferably 30 seconds to 1 minute, and more preferably 50 to 16 minutes
Post-curing can also be performed at 0°C. Drying and curing conditions may be appropriately selected depending on the solvent used, the amount of coexisting water, the curing catalyst, the type of adherend, etc.

In addition, the light irradiation can be performed by a method known per se. When using a high-pressure mercury lamp, a low-pressure mercury lamp, a xenon lamp, sunlight, etc. as a light source, the wavelength is usually 200~200 nm.
400nm ultraviolet I! (Particularly preferably 310 to 400
nm) is preferred, but other electromagnetic waves can be used as well.

There are no particular limitations on the conditions for light irradiation in the present invention, ie, the irradiation time, irradiation atmosphere, etc. Irradiation intensity is usually about 10-2
．． 000w/s/, preferably 500-1,000w
/d, and the irradiation time can be appropriately determined from 0.1 seconds to 30 minutes depending on the physical properties required for the product. Even under an oxygen atmosphere, the crosslinking and/or polymerization reactions of the present invention are not inhibited to that extent. In terms of irradiation efficiency, it is preferable to conduct the irradiation at a temperature that is at least m degrees and below the melting point of the glass transition of the molded product before irradiation.

Other curing methods include electron beam irradiation, and electron beam irradiation methods include the electrocurtain method and electroscanning method, and the irradiation atmosphere used is air or inert gas, but these methods are limited to these methods. The irradiation conditions are an acceleration voltage of 100 to 750 KV, preferably 150 to 300 KV.
, the irradiation am is 0, I KV to 500 Mrad, preferably 2 to 2004 rad.

In the present invention, when curing by ultraviolet irradiation, a photoinitiator can be added to accelerate the photopolymerization reaction. Specific examples include ketals such as benzyl dimethyl ketal, benzoin methyl ether, benzoin ethyl ether, benzoin-1-propyl ether, benzoin, benzoin such as α-methylbenzoin, 9,10-anthraquinone, 1-chloroanthraquinone, etc. , 2-chloroanthraquino/, 7 anthraquinos such as 2-ethylanthraquinone, 7 be/zophenones such as benzophenone, p-chlorobenzophenone, p-dimethylaminobenzophenone, 1-phenyl-2
-Hydroxy-2-methyl-1-propion, 1-(4
-isopropylphenyl)-2-hydroxy-2-methyl-1-propion, etc.
Examples include suberones such as cisvelor, sulfur-containing compounds such as diphenyl disulfide, tetramethylthiuram disulfide, and thioxa 7ton, and pigments such as methylene blue, eosin, and fluorescein, and these may be used alone or in combination of two or more companies.

The resin composition may contain lubricants (silica, talc, silicone, etc.), adhesion promoters, flame retardants (halogen compounds, phosphorus compounds, aluminum hydroxide, trioxide, etc.) within a range that does not impair the performance of the present invention. antimony, etc.), stabilizers (antioxidants, ultraviolet absorbers, polymerization inhibitors, etc.), 1111M agents (silicone-based, fluorine-based, inorganic-based), plating activators,
Other inorganic and organic fillers (talc, titanium oxide, gB element polymer fine particle pigments, dyes, calcium carbide, etc.)
may be added.

Furthermore, a woven or nonwoven fabric obtained by impregnating the resin composition of the present invention into a woven or nonwoven fabric, drying it, and then curing it can be used as a heat-resistant sheet for flexible printed circuit boards that has excellent heat resistance and a low dimensional change rate. can be used. The heat-resistant woven fabric or non-woven fabric used here is a heat-resistant fiber knitted fabric, non-woven fabric, or paper. A reinforcing material made of glass cloth, carbon fiber, aromatic polyamide fiber, cellulose paper, glass vapor, etc. is used, and the thickness of these materials is 10 μm to 1 airs, preferably 20 μm.
-100μ, particularly preferably 30-60μ.

(Function) The heat-resistant film of the present invention is based on a polyester lMl component, but because it contains a highly heat-resistant component that grows imide groups, it has a high degree of sophistication that conventional polyester films do not have. It exhibits heat resistance.

Moreover, since it has excellent flexibility, it can be a suitable material for heat-resistant films for flexible circuit boards and coverlay films that require a high degree of heat resistance.

(Examples) In order to explain the present invention more specifically, Examples are given below, but of course the present invention is not limited to these Examples in any way. In the Examples and Comparative Examples, parts refer to parts by weight.

As shown in Table-1 and Table-2, the resin compositions of Examples 1 to 4 and Comparative Examples 1 to 3 were each 50% by weight solution (however,
Methyl ethyl keto// as solvent = 40/
60 (injl ratio)) On a 100 μm thick polyester film, the coating thickness after drying is 20 to 30 μm.
It was coated with a wire bar so that it became m. then 100
After drying and curing for 5 minutes at ℃, the corresponding film was peeled off from the polyester film, and this film was further heated at 130℃.
We held a post-cure session at 10am. Various tests were conducted on the obtained film.

The results are shown in Table-3.

From Table 3, it can be seen that none of the comparative examples had excellent soldering iron resistance or folding durability, but the products of the present invention were excellent in all of these.

Table 1) Mitsubishi Gas Chemical Company BT3109 (Bismaleimi F
・Tori 7 Jin Friend Resin) Book 2) Tobu Kasei Co., Ltd. Evototo YDl1400 (Bisphenol Am Brominated Epoxy Tree II Rikyo 3) Shikoku Kasei Co., Ltd.
, Z (Imitaryl Compound) Table-2 1) Abbreviations indicate the following acid or glycol residues.

T: Terephthalic acid ■: Isofucric acid C: Sebacic acid E: Ethylene glycol N: Neobentyl glycol 2 Patent viscosity: Phenol/1,1,2.2-tetrachloroethane = f30/40 (weight n ratio) Measurement table at 30℃ -3 (Note) 1) 260℃X20 according to JIS C6481
Test in seconds.

Those with no abnormality were rated 0, and those with some change in appearance were rated x.

2 Soldering iron tip area 82.7■-1 (contact surface is flat, use an oval soldering iron, lightly contact at 350°C for 10 seconds, and if there is no abnormality, melt the 01 film)
And so.

3) JIS 8115 MIT method, R=0.381
, tested with a load of 500g. 1000 times or more is 01 or less is X.

(Effects of the Invention) According to the present invention, it is possible to provide a heat-resistant film suitable for use as a flexible printed circuit board or a coverlay film that can withstand a soldering bath at an abnormal temperature of 260° C., manual soldering at an abnormal temperature of 350° C., and thermocompression bonding.

Claims (1)

[Claims] At least 20 alkylene terephthalate repeating units
Saturated polyester resin containing (a) maleimide resin and/or maleimide-modified resin (b) in mol%, respectively (a) 85 to 40% by weight, (b) 1
A heat-resistant film comprising a reaction product containing 5 to 60% by weight.