JPS62130844A - Laminated film - 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 (a) Industrial Application Field The present invention relates to a laminated film, and more specifically, a polyester film having excellent mechanical properties, chemical stability, heat resistance, and dimensional stability and a conductive metal layer. This article relates to a laminated film that is extremely useful for flexible printed circuits, etc.

(b) Conventionally, laminated films in which a conductive metal layer is laminated on an electrically insulating film have been used for applications such as flexible printed circuits and tape carriers.
Its importance is increasing as electronic devices become smaller, lighter, and more precise. At present, polyester films and polyimide films are mainly used as electrically insulating films.

Polyester films, especially polyethylene terephthalate films, have excellent mechanical and electrical properties, but they do not have sufficient heat resistance; for example, stretched polyethylene terephthalate films shrink even at temperatures below their melting point, such as 230°C. The high rate of use severely limits the range of use, for example in flexible printed circuits having a polyester film as a substrate, which practically cannot be used for soldering. In addition, although polyimide film has excellent mechanical properties and heat resistance, it has a high equilibrium moisture content, does not have good dimensional stability and electrical properties, and has to be solution molded. The disadvantage is that it is very expensive. As other materials,
Various materials have been proposed as substrates for flexible printed circuits, including woven or nonwoven fabrics such as glass or aramid impregnated with a relatively flexible curable resin.

Although these materials have excellent heat resistance and dimensional stability,
There are problems with poor bending resistance and through-hole properties.

(c) Purpose of the invention Therefore, the present inventors have developed a novel substrate film and conductive base H4 layer that has the melt moldability and excellent mechanical properties of polyester, and has excellent heat resistance and dimensional stability. As a result of research aimed at providing a laminated film useful as a 7-lexiple printed circuit, etc., the present invention was achieved.

(d) Structure and Effects of the Invention In other words, the present invention uses 6,6'-(ethylenedioxy)di-2-7toic acid as the main acid component, and a fatty acid whose glycol main chain has 2 to 1 carbon atoms. This is a laminated film formed by laminating a conductive metal layer on at least one side of a polyester film containing group glycol as the main glycol component.

The present invention will be explained in detail below.

The polyester used in the present invention consists of a dicarboxylic acid component mainly consisting of 6,6'-(ethylenedioxy)di-2-naphthoic acid or its ester-forming derivative, and an aliphatic glycol having 2 to 10 carbon atoms in the glycol main chain. It can be produced by condensing the polyester with a glycol component mainly consisting of the following by a conventionally known polyester polymerization method.

In the present invention, a part of 6,6'-(ethylenedioxy)di-2-naphthoic acid or its ester-forming derivative may be replaced with other dicarboxylic acids, oxycarboxylic acids, or ester-forming derivatives thereof.

As such dicarboxylic acids, those represented by the following formula % can be used, for example. For example, terephthalic acid,
inophthalic acid, 2. -6-naphthalene dicarboxylic acid,
4.4'-diphenyldicarboxylic acid, adipine*, azelaic acid, cepatine powder.

Examples include cyclohexane-1,4-dicarboxylic acid.

Similarly, as the oxycarboxylic acid, for example, those represented by the following formula (7) % formula % (2) can be used. Examples include oxybenzoic acid, β-hydroxyethoxybenzoic acid, hydroxynaphthoic acid, β-hydroxyethoxynaphthoic acid, hydroxycagro/disperse, and 4-hydroxycyclohexanecarboxylic acid.

In the present invention, the ester-forming derivative used for the carboxylic acid component is a compound that can react with an aliphatic glycol and mainly forms an ester bond as a result of the reaction, such as a lower alkyl ester having 1 to 6 carbon atoms or Refers to esters such as haphenyl esters and acid halides such as acid chlorides.

When using 6,6'-(ethylenedioxy)di-2-naphthoic acid or its ester-forming derivative together with other dicarboxylic acids, oxycarboxylic acids, or their ester-forming derivatives as the dicarboxylic acid component, Other dicarboxylic acids, etc. are preferably used not less than 50 mols of the total acid components, more preferably 30 mols less of the total acid components, especially 20 mols less of the total acid components.

In the method of the present invention, aliphatic glycols having 2 to 10 carbon atoms in the glycol main chain are used as the glycol component of the polyester, but other diols may be used in combination with these as glycol components.

The glycol main chain refers to the shortest chain portion connecting two hydroxyl groups of glycol.

The above-mentioned aliphatic glycol may be straight or branched, as long as the main chain has 2 to 10 carbon atoms, may be interrupted by a oxygen atom, or may contain a carbon ring. Good too.

For example, linear glycol is expressed by the following formula (1) % formula % () (Here, n is a number from 2 to 10.) The one represented by is preferable.

For example, branched glycol has the following formula (■)'HO+ C
−)mOH・・・・・−(1)′.

Examples of the aliphatic glycol include ethylene glycol, L2-propylene glycol, trimethylene glycol, nato-2-methylene glycol, and neopentyl glycol.

2-Methyl-1,4-butanediol, hexamethylene glycol, octamethylene glycol, flyl tylene glycol, cyclohexane-1,4-dimethatol, cyclohexane-1,4-diol, 1,4-bis(
β-hydroxyethoxy)benzene, etc. can be used.

Other diols used as other glycol components include, for example, the following formula 〇HO-R'-OH...0 (where y
is an aromatic group. ) are preferably used. Cholera, for example, hydroquinone, resorcinol, 2,6-hydroxynaphthalene, 4,4'-dihydroxydiphenyl, 2,2-bis(4-hydroxyphenyl)propane,
Bis(4-hydroxypheni/I/) sulfone, 1.1
-ni'su(4-hydroxyphenyl)cyclohexane,
Bis(4-hydroxyphenyl)ethyl and the like.

When such other diols as glycol components are used in combination, such other diols are preferably 50 moles less than the total glycol component, more preferably 30 moles less than the total glycol component, especially the total glycol component. 20 mol less of the ingredient is used.

The polyester used in the present invention includes a compound having one ester-forming functional group such as benzoic acid and benzoylbenzoic acid within the range where the polyester is substantially linear; glycerin, pentaerythritol, trimellitic acid, A compound having three or more ester-forming functional groups, such as pyromellitic acid, or an ester-forming derivative thereof may be allowed to coexist and copolymerized. A compound having three or more ester-forming functional groups can be used, for example, in an amount of 0.2 molti or less based on the total acid component.

The polyester used for the laminated film in the present invention is
P-chlorophenol/tetrachloroethane (40/6
It is preferable that the intrinsic viscosity determined by measurement at 35°C using a mixed solvent of 0 weight ratio) is 0.4 or more, more preferably 0.5 or more, and particularly preferably 0.6 or more. . Such polyesters are crystalline and have a high melting point; for example, a homopolyester of 6,6'-(ethylenedioxy)di-2-naphthoic acid and ethylene glycol has a melting point of 294°C, and a homopolyester of polyethylene terephthalate has a melting point of 294°C; It has a melting point of 255°C, which is 40°C higher, and has extremely excellent heat resistance.

The aromatic polyester of the present invention may optionally contain other thermoplastic polymers, stabilizers such as ultraviolet absorbers, antioxidants, and plasticizers.

A lubricant, a flame retardant, a pigment, a nucleating agent, a filler, or a reinforcing agent such as glass fiber, carbon fiber, asbestos, etc. can be added as necessary.

The polyester film used in the present invention is usually produced as follows. The polyester is dried, melted at a temperature as high as the polymer melting point (Tm), but as low as 350°C, more preferably as low as 330°C, and extruded through a film forming gouge, followed by polymer glass transition. It is brought into contact with a rotating drum kept at a lower temperature (Tg) and rapidly cooled.

The unstretched film obtained in this way has excellent properties such as heat resistance and hydrolysis resistance as it is, and can be used as is, but the film has excellent properties such as strength. In order to further improve the performance, the unstretched film may be uniaxially or biaxially stretched. The stretching is preferably carried out at a temperature in the range of (Tg-10)°C to (Tg-1-so)°C so that the area magnification is 2 times or more, more preferably 5 times or more, particularly 8 times or more. In the case of biaxial stretching, the stretching method may be sequential or simultaneous. The stretched film is preferably stretched or heat treated at a temperature between the stretching temperature and (Tm -10)'C.

According to the research of the present inventor, when the aromatic polyester of the present invention is treated at elevated temperature in an atmosphere containing oxygen or molecular oxygen such as air, crosslinking occurs between molecular chains. It has become clear that molded products having superior mechanical properties, heat resistance, mulberry resistance, and dimensional stability can be obtained. In the present invention, films subjected to such crosslinking treatment are also preferably used. Such crosslinking treatment is preferably carried out at a treatment temperature ('rt) and treatment time (1) that simultaneously satisfy the following formula %.
It will be carried out in Preferably, the reaction is carried out under conditions where the following formulas are satisfied at the same time.

1n t≧16.9X10"X-26,
8Tl+273.2 and 200≦Tt<Tm Moreover, it is particularly preferably carried out under conditions where the following formulas are simultaneously satisfied.

1n t≧16.9 X 10' X --26,5T
1+273.2 and 230≦Tt<Tm The film crosslinked under the above conditions has 150
It is cross-linked so that it does not completely dissolve in the mixed solvent of P-chlorophenol/tetrachloroethane (mixed weight ratio: 40/60) heated to ℃, and some undissolved portion remains. It does not melt at temperatures below 400°C.

Similarly, according to the research of the present inventor, the aromatic polyester of the present invention can also be produced by being heat-treated stepwise or continuously for a short time under specific temperature conditions without performing the above-mentioned crosslinking treatment. It was clearly shown that heat resistance and dimensional stability were improved. While the above crosslinking treatment improved the physical properties of the molded article by crosslinking between polymer chains, in this heat treatment the melting point of the polymer in the molded article gradually approaches the temperature of the final crystalline melting point of the polymer. It is believed that the physical properties of the molded product will be improved.

Such heat treatment is preferably performed according to the following formula: %formula%( It is carried out at a temperature T* (°C) that satisfies the following. Temperature T.

The heat treatment at (°C) may be performed under any of the following conditions: constant length, tension, or limited shrinkage, and the treatment atmosphere must be a gas such as air, nitrogen, or argon, or a liquid such as silicone oil. I can do it. For example, the processing time is 0
．． The time can be 1 second to 60 minutes, but usually 1 second to 4 minutes.
5 minutes, more precisely 5 seconds to 30 minutes.

For example, the aromatic polyester is a homopolymer having 6,6'-(ethylenedioxy)di-2-naphthoic acid as the acid component and ethylene glycol as the glycol component,
In the case of a film obtained by forming this homopolyester into a film as described above and biaxially stretching, the Ts of this film is
The temperature is 250°C, and the temperature for T-work is 265°C. Therefore, for this film, the heat treatment is 250≦T! It should be performed at a TI (°C) in the range <265. This film 2
Heat treatment was performed at 60°C for 5 minutes. A part of this heat-treated film was crosslinked in air at 230°C for 60 hours in the same manner as above, and DSC showed that Ta and TmR had increased to 283°C.

Therefore, if this film is to be heat treated again in the summer, the heat treatment should be carried out at a TI (°C) in the range of 263≦T (283). Temperature Tz (°C) that continuously satisfies the above range
By heat-treating the molded article of the aromatic polyester of the present invention, it is possible to raise the polymer melting point of the molded article to the final crystal melting point (for example, 294 ° C. in the case of the above homopolymer) in a short time and without any problems in the process. can.

In the present invention, such a film can also be preferably used.

The laminated film of the present invention is obtained by laminating conductive gold F4N on at least one side of the above film. There are various methods of lamination, including bonding a conductive metal foil, layering a layer on a film, and electroless plating on a film. It can be broadly divided into methods of depositing layers. Copper, aluminum, etc. are used as the conductive metal layer, and copper foil is particularly preferably used. Further, as copper foil, there are electrolytic copper foil and rolled steel foil, and electrolytic steel foil is generally used. Particularly when flexibility is required, rolled steel foil is preferably used.

When using an adhesive, it is preferable to use a surface-oxidized steel foil with good adhesive properties. As a method for forming the conductive gold lI4 layer, especially the copper layer, on the film, a method using a combination of electroless steel plating and electrolytic steel plating is also preferably used.

A lamination method using adhesive is a generally widely used method, and can also be applied to the laminated film of the present invention.

It is preferable to use a material that not only has good adhesion to the polyester film and conductive metal foil, but also has excellent electrical properties and heat resistance. In the laminated film of the present invention, adhesives generally used for polyester films and adhesives for polyimide films can be used.

Examples of adhesives for polyester films include urethane-modified polyester adhesives.

Polyester-modified epoxy adhesives and the like are preferably used, and as adhesives for polyimide films, phenol-modified epoxy adhesives, nylon-modified epoxy adhesives, modified acrylic adhesives, nitrile rubber-modified phenol adhesives, etc. are preferably used. Adhesion is achieved by continuously applying an adhesive solution as exemplified above to the film using a coating means such as a roll coater, and after drying the solvent by heating, the film is pressed with a conductive metal foil using a heated roller. You can do it. The polyester laminate film of the present invention can be industrially advantageously produced by the method described above.

Moreover, in the polyester laminated film of the present invention,
It is also possible to form the conductive metal layer by electroless plating. In this case, the #4 layer is formed on the film by subjecting the film to surface activation treatment using a method known per se, and then immersing the #4 layer in an electroless plating solution. can. If the thickness of the copper layer is less than about 10 μm, electroless plating alone can achieve the purpose, but if a thicker steel layer is required, after performing electroless plating,
By using electrolytic plating in combination, it is easier to obtain a copper layer with a desired thickness. Further, in order to improve adhesion to the copper foil, it is preferable to perform etching such as alkali treatment or amine treatment in advance.

As described above, since the laminated film of the present invention uses a high melting point polyester film as a substrate, it has excellent electrical properties and also has heat resistance sufficient to withstand soldering at 260°C. . In addition, since it has appropriate flexibility, it can be bent freely, has a low shrinkage rate, and has excellent process stability.

The laminated film of the present invention can be effectively applied to wood materials that require heat resistance and flexibility, such as 7-lex blueprint circuits, tape-print circuits, and the like.

The present invention will be explained in more detail below with reference to Examples. In the examples, "parts" means "parts by weight",
Also, glass transition point (Ts), melting point (TB tT, HtT
m) was measured by DSC at a heating rate of 20°C/min.

In addition, heat resistance test for cattle was measured according to JIS-C-6481 (Test method for copper-clad laminates for printed circuits). The thermal shrinkage rate is expressed as the percentage of shrinkage when a film with a length of 5 cm and a width of 1 cm is immersed in silicone oil heated to a predetermined temperature for 30 seconds.

Example 1 458 parts of diethyl 6.6'-(ethylenedioxy)di-2-7toate (melting point 193°C), ethylene glycol TAOS, and 0.1 part of titanium tetrabutoxide were charged into a reactor equipped with a rectification column. The reaction mixture was heated to 200 to 260°C to distill off the ethanol produced by the reaction. After almost all the ethanol was distilled out, the reactants were transferred to a reactor equipped with a stirrer, a nitrogen gas inlet, and a distillation outlet, and reacted at 290°C for 30 minutes at normal pressure in a nitrogen gas flow, and then the reaction temperature was increased to 310°C. The temperature was raised to ℃, and the pressure inside the system was gradually reduced to an absolute pressure of about 0.2 run Hg after 15 minutes.
This was followed by further reaction for 20 minutes. The obtained polymer is transparent when melted, but does not crystallize even when rapidly cooled, has an intrinsic viscosity of 0.69, a glass transition point of 129°C, and a melting point of 294°C.
Met. Next, the polymer was crushed and dried for 32 hours.
It was melted at 0°C, extruded through a T-die with a lip spacing of 0.31IJI, and placed tightly on a rotating drum maintained at about 80°C.
An unstretched film was obtained by rapid cooling.

This unstretched film has a thickness of approximately 80 μm. The physical properties in the membrane direction were as follows.

Strength 7.9 Edge/d Elongation 112% Young's modulus 271 Kq/d Appearance Milky white translucent Aging at 260℃ 0.1 inch Next, after degreasing the above film with acetone, adhesion according to the following composition The agent was applied using a bar coater (A20) and dried with hot air at 120°C for 10 minutes. Electrolytic steel foil with a thickness of 35ti was pressed onto the adhesive-coated film between a pair of rollers heated to 150°C, and then heated under hot air at 120°C at 30°C.
It was then heat-treated at 170°C for 30 minutes and then at 200°C for 5 minutes. When the obtained laminated film was subjected to a heat resistance test for 60 seconds using a 260'C solder bath, it was found to have excellent heat resistance without any abnormalities. Moreover, the peel strength (180' direction) is 1.
It was 9 breasts/cm.

Example 2 The polymer obtained in Example 1 was used at a T-die lip spacing of 0.5B.
An unstretched film was obtained by rc extrusion in the same manner as above, and then the film was successively biaxially stretched at 145° C. to 13.5 times 1i and 5.0 times in width. Next, the film was heated to 265°C under 5 foot length.
2 minutes, further heat treated at 260°C for 2 minutes under limited shrinkage of about 5 inches,
Got the film.

The physical properties of the film were as follows.

-Strength in cuff direction/second axis direction 14/25
(K17m”) Elongation 31/
18 (ch) Young's modulus 44 o/ 80
0 (Kg/m') 260℃ heat shrinkage rate 0.91
0.7 (h) The film was then laminated with a 35μ thick electrolytic copper foil in the same manner as in Example 1. The obtained laminated film had a peel strength of 1.5 Kg/σ and good soldering heat resistance at 260°C.

Example 3 The biaxially stretched film obtained in Example 2 was treated with a fixed length in air at 230°C for 50 hours (hereinafter referred to as crosslinking treatment), resulting in a mixed solvent of P-chlorophenol/tetrachloroethane (40/60 weight ratio). It was not soluble in water, and even when it was left on an iron plate heated to 400°C for 5 minutes, it did not melt and was crosslinked.

-Strength in cuff direction/second axis direction 14/25 (~/
m1) Elongation 31/18
(ch) Young's modulus 440/800 (K4/m'
) 260℃ heat shrinkage aging 0.910.7 (chi)
The film was then laminated in the same manner as in Example 1 with a 35μ thick electrolytic steel foil. The obtained laminated film had a peel strength of 1.5 Kg/cln and good soldering heat resistance at 260°C.

Example 4 When the biaxially stretched film obtained in Example 2 was treated in air at 230° C. for 50 hours under a fixed length (hereinafter referred to as crosslinking treatment), P-
It was insoluble in a mixed solvent of chlorophenol/tetrachloroethane (40/60 weight ratio), and was crosslinked without melting even after being left on an iron plate heated to 400°C for 5 minutes. When the DSC of this crosslinked film was measured, T3 was 250°C.
TmR was 265°C.

The above-mentioned uncrosslinked biaxially stretched film 1 was heat-treated in air at a temperature of 260° C. between the above-mentioned TlI and T for 51 minutes under a constant length. When the obtained film was crosslinked under the same conditions as above, T was 263°C and T was 283°C. It can be seen that the above heat treatment at 260° C. for 5 minutes in air increased the melting point.

Next, the film obtained by heat treatment at 260°C for 5 minutes was
Immerse in 0% monoethylamine aqueous solution for 1 minute at room temperature,
Washed with water. Next, it was immersed in sensitizer 1.5-101B for electroless copper plating manufactured by Hitachi Chemical Co., Ltd. for 10 minutes and washed with water, and similarly immersed in adhesion promoter ADP-201 for 5 minutes and washed with water. Next, apply the same electroless copper plating solution CUST-201 at 25℃.
After immersion in water for 15 minutes and washing with water, electrolytic steel plating was performed using a sulfuric acid steel bath to obtain a double-sided steel-clad laminated film with a copper foil thickness of approximately 30 μm. In the laminated film, one of the copper foils
The peel strength in the 800 direction was 0.8 Kg/cm, and no abnormality was found as a result of a soldering heat resistance test at 260° C. for 30 seconds.

Claims (1)

[Claims] The main acid component is 6,6'-(ethylenedioxy)di-2-naphthoic acid, and the glycol main chain has 2 to 2 carbon atoms.
1. A laminated film comprising a polyester film containing 10 aliphatic glycols as the main glycol component, and a conductive metal layer laminated on at least one side of the film.