JPS62149437A - Heat-resistant multilayer 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] [Industrial Application Field] The present invention relates to a heat-resistant plastic film, and in particular, it is used for laminating metal foils such as copper, aluminum, iron, etc. This invention relates to a base film for turning to form a circuit.

[Prior art]

Application for laminating plastic film and metal foil, i.e. flexible printed circuit (hereinafter abbreviated as FPC)
Applications such as sheet heating elements, IC film carriers, electromagnetic shielding films, etc. are rapidly expanding due to the recent rapid development of peripheral technology for electronic devices and the trend of making products lighter, thinner, shorter and smaller.

Films used for these applications are currently f' + J
Imide film, pyriester film, and glass epoxy film are used, each of which has advantages and disadvantages. That is, polyimide films have some problems in that they are extremely expensive and have hygroscopic properties. Pyriester films have poor heat resistance, especially in terms of soldering heat resistance, and are therefore used only in applications with low thermal requirements.

The biggest drawback of Glass E7 Pixi Film is the problem with the glass cloth itself, namely the lack of flexibility, and the problem of the glass cloth flying out of the system during the Zunching process. Although there is a problem in terms of price, the reality is that pyriimide film accounts for 60 yen of the market share for this use. On the other hand, heat-resistant films other than the above three types have also been developed in recent years and have begun to be considered for use in metal foil laminates, mainly for circuits. Polysulfone film, daryether sulfone, polyetherimide, polyarylate, moon? This includes thermoplastic heat-resistant films such as rietheretherketone. However, these heat-resistant films have a linear expansion coefficient of 4 to 5 x 10-5.
℃−1 and 7I? Reester film 1. '3 X 1
Since the 0-pyriimide film is more than 9 times larger than 1.6 x 10''-5, when laminated with a metal foil having a coefficient of linear expansion of 1 to 2 x 10''-5, the problem arises that the film curls with the film side inward. In lamination processing, before the film and metal foil are completely bonded, it is normal to go through a heat-pressing process or a heat-curing process to harden the adhesive, and the difference in linear expansion coefficient between the film and metal foil is If it is large, there will be a difference in size between the top and the melon when it is returned to room temperature, resulting in curling.

In addition to the above-mentioned heat-resistant resins, technology to make the coefficient of linear expansion equivalent to that of metals has already been studied in the field of engineering plastics, and many examples have been put into practical use, but none of them are available in film form. This applies only to three-dimensional molded products. Since this method involves filling a high proportion of inorganic filler to reduce the coefficient of linear expansion, the molded product itself is rigid and has low fragility, and when formed into a film, it can only be extremely brittle.

[Purpose of the invention]

The purpose of the present invention is to provide a base film for FPC, IC tape carriers, etc. that does not curl when laminated with metal foil, has high flexibility as a film, and does not break brittle even when bent. Our goal is to provide a heat-resistant film that does not require heat.

[Structure of the invention]

The present invention is a heat-resistant film mainly composed of hylyetherimide (hereinafter abbreviated as PEI), and has a three-layer structure of an intermediate layer and upper and lower surface layers sandwiching the intermediate layer. The ratio with filler is 80:2 by weight
It is a heat-resistant multilayer film characterized in that the ratio is 0 to 40:60, and the upper and lower surface layers are made of thermoplastic resin with a glass transition temperature of 135° C. or higher.

The main components of the present invention are three layers: an upper surface layer, an intermediate layer, and a lower surface layer, but adhesive resin j6 may be used between the upper surface layer and the intermediate layer, and between the intermediate layer and the lower surface layer. The content of the contact resin layer is not defined by the present invention. Although the composition ratio of the intermediate layer to the upper and lower surface layers is not defined by the present invention, it is preferably 2080 to 90:10.

The PEI used in the intermediate layer according to the present invention is defined as a thermoplastic polymer containing an aromatic nuclear bond, an ether bond, and an imide bond in its structural unit, and includes, for example, one having the following structural formula.

The other component of the interlayer blend is the inorganic filler.
Silicon-containing inorganic particles such as sand stone, clay, talc, mica, and kaolin, calcium-containing inorganic particles such as calcium carbonate and calcium silicate, alumina, translatinated titanium, magnesium oxide,
Refers to inert non-contact particles such as metal oxides such as antimony oxide and zinc oxide. These inorganic fillers may be subjected to surface treatment with various coupling agents. Further, the average particle diameter is preferably 10 μm or less, but this is not defined by the present invention. The weight ratio of PEI to inorganic filler in the intermediate layer blend according to the present invention is defined in the range of 80:20 to 40:60. If the weight ratio of the inorganic filler is less than 20%, the desired effect of reducing linear expansion will not be sufficient, and when gold is laminated with foil, curling will occur and the product will not be able to withstand optical applications.1. Similarly, if it exceeds 60%, the flexibility of the film will be extremely reduced and it will break brittle when bent.

In the present invention, a thermoplastic resin having a glass transition temperature of 135° C. or higher is used for the upper and lower surface layers. Specifically, prietherimide (P
EI), bolyarylate (e.g. Yuyuchika v4 Rimmer)
, - riethersulfone (IC1 company VICTREX
-PES), N') fruho:y (U,C.

C, UDEL), &IJ ether ether ketone (
ICI's VICTREX-PEEK). If the glass transition temperature is less than 135°C, the heat resistance of the PEI and inorganic filler blend of the intermediate layer is impaired, and sufficient heat resistance cannot be obtained. The upper and lower surface layers may be made of the same resin or may be made of different resins. Alternatively, it may be a blend of a plurality of resins. In addition, in order to improve the handling properties of the film, blocking agents such as inorganic powders such as talc, silica, and calcium carbonate are added to the thermoplastic resin (/
C may be blended in a small amount. In this case, if the amount of the antiblocking agent exceeds 2.0%, the flexibility of the entire film will decrease, which is not preferable. Further, coloring agents such as antioxidants, ultraviolet absorbers, antistatic agents, carbon black, and titanium oxide may be added to the plastic resins of the upper and lower surface layers, if necessary.

The method for producing the heat-resistant multilayer film of the present invention includes a coextrusion lamination method, an extrusion lamination method, a dry lamination method,
Any of the press heat compression bonding method, the method of solvent casting the upper and lower surface layers into the intermediate layer, or a combination of these methods may be used. However, since the intermediate layer alone has low flexibility and is prone to brittle fracture when bent, it is preferable to use a method of laminating the upper and lower surface layers at the same time as forming the intermediate layer, i.e., a co-extrusion lamination method or an extrusion lamination method while extruding the intermediate layer. .

〔Effect of the invention〕

The heat-resistant film of the present invention has a linear expansion coefficient of approximately 1.
3 x 10-5 to 3. OX 10-', it was possible to obtain a linear expansion coefficient equivalent to that of a pyriimide film or a ceriester film, and even after laminating with metal foil such as copper or aluminum, there was little curling and no practical problems occurred. Also, heat resistance, so-called solder heat resistance26
Thermal dimensional stability against a 0° C. solder bath could also be maintained due to the synergistic effect of the heat resistance inherent to PICI in the intermediate layer and the inorganic filler.

Furthermore, with regard to brittleness when bent, a film with sufficient flexibility was obtained.

The main purpose and novelty of the present invention is, firstly, by sandwiching the intermediate layer with a thermoplastic resin layer, which can only be a very brittle film by itself, the flexibility can be greatly improved. and secondly, it was found that the coefficient of linear expansion and heat resistance of the entire film are similar to the properties of the intermediate layer.

Examples will be explained below.

Example-1; As the intermediate layer, P):I (IJ manufactured by GE)
LTEM-1000) 60 parts Ii and average particle diameter 2
40 parts by weight of μ talc were mixed and kneaded using a kneader to obtain R-let. Three extruders were each supplied with PIIJ as an upper surface layer, the same <PEI as a lower surface layer, and the above-mentioned PEl-talc blend as an intermediate layer, and extruded through a three-layer die and laminated together to form a film with a thickness of 100 μm. The thickness of each layer is 30μ and 3μ for the top, middle, and bottom layers, respectively.
They were 5μ and 30μ.

Example-2: As the middle layer, PEI (GE company UL
TEM-1000) 70 parts by weight and 30 parts by weight of silica powder having an average particle size of 5 μm were kneaded using a mixer to form R-let.

IJ ether x as the upper surface layer for each of the three extruders
-Teh))-Toy (1 (4 companies VICTREX -P
EEK), the same pyrietheretherketone as the lower surface layer, and the previously R-retted PEl-silica blend as the middle layer were extruded through a three-layer die, and laminated and integrated to form a film with a thickness of 125 μm. The thickness of each layer was 45μ, 35μ, and 45μ for the upper, middle, and lower layers, respectively.

Example-3: As an intermediate layer, 70 parts by weight of PEL and 30 parts by weight of calcium carbonate having an average particle size of 6 μm were mixed,
After being mixed in a mixer, it was left on the left.

Separately, PEI alone was extruded through a coat hanger die, 6
A polyetherimide film with a thickness of 0 μm was obtained.

The previously R-retted PEl-calcium carbonate blend was extruded with a coat hanger die to a thickness of 50μ, and at the same time, the previously obtained 60μ polyetherimide film was sandwich-pressed from above and below to the melt extrudate, and laminated. Integrated. The average thickness of the film was 170μ.

Comparative Example-1: 170Mf& parts of PE and 30 parts by weight of Merck having an average particle diameter of 2μ were mixed and kneaded in a kneader to form a left. The obtained left material was extruded using a T-die extruder and wound up as a 100 μm film.

Comparative Example-2; PEI was extruded using a coat hanger die extruder and wound up as a 125μ film.

Comparative example-3; Jelly ether sulfone (IC1 company VICT
REX-PES 200F) 60 heavy background part and silica powder having an average particle size of 5 μm were mixed, and then kneaded with a mixer to form a left. The obtained left was extruded using a coat hanger die extruder to form a 125μ film.

Examples 1, 2, and 3 Comparative Examples 1, 2, and 3 were tested for each performance described below. Report the results in Table-IK*.

(1) Flexibility: The film was bent at 180° to examine whether the film would break brittle. Items that break, such as glass, or items that partially or completely break when bent
, No cracks or breaks were selected as one.

(2) Cu lamicar property: Electrolytic Cu foil 35μ and film are attached via adhesive at 160°C for 30 minutes, 10) c9/c
The radius of curvature of the curl of the resulting Cu laminate film was measured, and the radius was expressed in terms of saliva.

(3) Coefficient of linear expansion: 30 using a linear expansion measuring device manufactured by Shimadzu Corporation
The linear expansion coefficient between 150°C and 150°C was measured.

(4) Solder heat resistance: The film was immersed in a solder bath at 260° C. for 10 seconds to examine its deformation and shrinkage rate. Regarding deformation, those with large deformation were marked as ×, those with moderate deformation were marked as ○, and those with almost no deformation were marked as ○. The shrinkage rate is shown as excellent.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the structure of the heat-resistant multilayer film of the present invention.

Claims (1)

[Claims] 1. A heat-resistant film mainly made of polyetherimide, which has a three-layer structure of an intermediate layer and upper and lower surface layers sandwiching the intermediate layer. The intermediate layer is composed of polyetherimide and an inorganic material. A filler blend in which the weight ratio of polyetherimide to inorganic filler is 80:20 to 40:
60, and the upper and lower surface layers are a thermoplastic resin having a glass transition temperature of 135° C. or higher. 2. The heat-resistant multilayer film according to claim 1, wherein the inorganic filler is silicon-containing or calcium-containing inorganic particles. 3. The heat-resistant multilayer film according to claim 1 or 2, wherein the thermoplastic resin of the upper and lower surface layers is polyetherimide or polyetheretherketone.