JP5364550B2 - Syndiotactic polystyrene resin film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a syndiotactic polystyrene resin film excellent in adhesiveness and an electrical characteristic. <P>SOLUTION: There is provided the syndiotactic polystyrene-based resin film in which a ratio of the number of peeled lattice cells to all the number of lattice cells is 20% or less in a grid peel test in thermo-compression bonding to a copper sheet at 200&deg;C and 50 kgf/cm<SP>2</SP>and for one minute. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a syndiotactic polystyrene resin film, a laminate including the same, and a coverlay film for a flexible printed board using the laminate.

There are two types of wiring boards for electronic devices: a plate-shaped rigid type printed wiring board and a flexible printed circuit board on which a circuit is formed on a heat-resistant film.
A flexible printed wiring board is formed by forming a copper wiring on a polyimide or liquid crystal polymer film, and further bonding a coverlay film made of polyimide or a liquid crystal polymer film for the purpose of preventing or protecting the copper wiring (Patent Document 1). , 2).
In general, a polyimide film or a liquid crystal polymer film used for a coverlay film has high heat resistance and flame retardancy, but has a relatively high dielectric loss tangent and a large loss of electric signal.

  On the other hand, Patent Documents 3 and 4 disclose a coverlay film mainly composed of a styrenic resin composition having a syndiotactic structure and a thermoplastic resin. Syndiotactic polystyrene resin films are excellent in electrical properties, but have low surface tension and are difficult to adhere to other materials.

JP 2000-286537 A JP 2006-261383 A JP 2001-53422 A JP 2001-40115 A

  An object of the present invention is to provide a syndiotactic polystyrene resin film excellent in adhesiveness and electrical characteristics.

According to the present invention, the following syndiotactic polystyrene resin films and the like are provided.
1. A syndiotactic polystyrene-based resin film having a mass number of 20% or less with respect to the total mass number in a cross-cut peel test when thermocompression bonded to a copper plate at ²⁰⁰ ° C., 50 kgf / cm ² for 1 minute.
2. Syndiotactic polystyrene resin film that is irradiated with ultraviolet rays on at least one side.
3. The syndiotactic polystyrene resin film according to 1 or 2, wherein the syndiotactic polystyrene resin is a homopolymer of styrene, a copolymer of styrene and paramethylstyrene, or a copolymer of styrene and ethylene.
The laminated body which laminated | stacked at least 1 layer on the syndiotactic polystyrene-type resin film of any one of 4.1-3.
5. The laminate according to 4, wherein the layer is a polyimide film or a liquid crystal polymer film.
6). 6. The laminate according to 5, wherein the syndiotactic polystyrene resin film and the polyimide film or liquid crystal polymer film are laminated via an adhesive layer.
A cover lay film for a flexible printed board using the syndiotactic polystyrene resin film according to any one of 7.1 to 3 or the laminate according to any one of 4 to 6.

  ADVANTAGE OF THE INVENTION According to this invention, the syndiotactic polystyrene-type resin film excellent in adhesiveness and an electrical property can be provided.

It is a figure which shows one Embodiment of the laminated body of this invention.

The syndiotactic polystyrene-based resin film of the present invention has a mass number of 20% or less with respect to the total mass number in a cross-cut peel test. The cross-cut peel test is performed by thermocompression bonding the SPS film to a copper plate at 200 ° C. and 50 kgf / cm ² for 1 minute. The peeled mass number is preferably 15% or less, more preferably 10% or less. The cross-cut peel test method is described in the examples.

The syndiotactic structure of syndiotactic polystyrene resin (SPS) is a syndiotactic structure, that is, phenyl groups that are side chains with respect to the main chain formed from carbon-carbon bonds are alternately arranged. It has a three-dimensional structure located in the opposite direction, and its tacticity is quantified by nuclear magnetic resonance ( ¹³ C-NMR) with isotope carbon. ^The tacticity measured by the ¹³ C-NMR method can be indicated by the abundance ratio of a plurality of consecutive structural units, for example, a dyad for two, a triad for three, a pentad for five. . The SPS used in the present invention is usually 75% or more of racemic dyad, preferably 85% or more, or 30% or more, preferably 50% or more of racemic pentad. Styrene), poly (halogenated styrene), poly (halogenated alkyl styrene), poly (alkoxy styrene), poly (vinyl benzoate), hydrogenated polymers thereof, and mixtures thereof, or based on these A copolymer etc. are mentioned. Poly (alkyl styrene) includes poly (methyl styrene), poly (ethyl styrene), poly (isopropyl styrene), poly (tertiary butyl styrene), poly (phenyl styrene), poly (vinyl naphthalene), poly (vinyl) Examples of poly (halogenated styrene) include poly (chlorostyrene), poly (bromostyrene), and poly (fluorostyrene). Examples of the poly (halogenated alkyl styrene) include poly (chloromethyl styrene), and examples of the poly (alkoxy styrene) include poly (methoxy styrene) and poly (ethoxy styrene).

  A preferred SPS is a homopolymer of styrene, a copolymer of styrene and paramethylstyrene, or a copolymer of styrene and ethylene. The paramethylstyrene content in the copolymer of styrene and paramethylstyrene is preferably 1 to 20 mol%, and the ethylene content in the copolymer of styrene and ethylene is preferably 1 to 50 mol%.

In addition, at least one surface of the SPS film of the present invention is irradiated with ultraviolet rays (UV treatment). By irradiating with ultraviolet rays, the adhesiveness of the SPS film to the printed substrate can be improved, and the peel rate can be reduced to 20% or less in the cross-cut peel test. UV treatment can also be performed on both sides of the SPS film.
The ultraviolet irradiation is performed using an ultraviolet irradiator or the like, preferably at an irradiation amount of 500 to 2000 mJ / cm ² , more preferably 1000 to 2000 mJ / cm ² .
In the present invention, ultraviolet rays refer to electromagnetic waves having a wavelength of 380 nm or less.
Further, corona treatment and nitrogen plasma treatment are not preferable because the film peeling rate after thermocompression bonding cannot be reduced to 20% or less.

  The SPS film can be obtained by stretching SPS. Examples of the stretching method include sequential and simultaneous biaxial stretching, and tenter stretching is preferred. The stretching temperature is preferably 100 ° C to 110 ° C. The thickness of the SPS film is not limited, but is usually about 1 μm to 200 μm.

  The laminate of the present invention is formed by laminating the SPS film and one or more other layers. The other layer is preferably a polyimide film or a liquid crystal polymer film.

A polyimide resin film etc. are mentioned as a polyimide film.
Liquid crystal polymers are obtained from aromatic or aliphatic dihydroxy compounds, aromatic or aliphatic dicarboxylic acids, aromatic hydroxycarboxylic acids, or compounds such as aromatic diamines, aromatic hydroxyamines or aromatic aminocarboxylic acids and derivatives thereof. And liquid crystal polymer.

  The SPS film is excellent in electrical properties, but has lower heat resistance and flame retardancy than the above film. Therefore, the laminate obtained by laminating the SPS film and the above film is excellent not only in electrical characteristics and adhesiveness but also in heat resistance and flame retardancy. When used for a coverlay film, there is no problem with the heat resistance in reflow used for joining circuit contacts. The laminate is adhered to the circuit by hot pressing with the SPS film surface as the circuit side (inner layer), polyimide film, liquid crystal film, etc. as the outer layer. Thus, an electric loss on the circuit surface side can be reduced, and a flexible printed circuit board (FPC) having heat resistance and flame retardancy as a base can be provided.

  The laminate of the present invention can be produced by extrusion molding, T-die film-forming stretching method, laminate stretching method, inflation, or the like. Further, the SPS film and the above layer can be laminated via an adhesive layer. As the adhesive layer, for example, thermoplastic resins such as acrylic resins, epoxy resins, polyamide resins, polyimide resins, polyolefin resins, maleimide resins, phenoxy resins, and the like can be used, including thermosetting resins. You can also.

  FIG. 1 shows an embodiment of the laminate of the present invention. In this laminate 1, an SPS film 10 and a polyimide film or a liquid crystal polymer film 20 are laminated via an adhesive layer 30. Although not limited, for example, the thickness of the SPS film 10 is 10 to 100 μm, the thickness of the polyimide film or the liquid crystal polymer film 20 is 10 to 100 μm, and the thickness of the adhesive layer 30 is 5 to 50 μm.

Additives such as the SPS film and antioxidant of the present invention can be contained in an amount of 0.05% by weight or more.
Moreover, the laminated body of this invention can contain a polyimide film or a liquid crystal polymer film, and an adhesive layer other than an SPS film.

Reference example 1
Idemitsu Kosan Co., Ltd. Syndiotactic Polystyrene Resin (SPS) Zarek 90ZC was stretched at a stretching temperature of 110 ° C. by tenter stretching to obtain a film having a thickness of 20 μm. One side of this film was subjected to UV treatment at 1000 mJ / cm ² using an ultraviolet irradiator. The UV-treated surface was brought into close contact with a copper plate having a thickness of 100 μm, and hot pressing was performed at 200 ° C., 50 kgf / m ² for 1 minute.

Thereafter, 100 squares (1 square: 5 mm × 5 mm) of grids were cut from the SPS film side with a cutter knife, and 3M cellophane tape “Scotch 313” was pressed into the grids and peeled. The number of peels in 100 squares was divided by the total number of squares, and the percentage was calculated according to the following formula. The results are shown in Table 1.
Peeling rate by cross-cut test = (number of peeled cells / total number of cells) × 100 (%)

Reference example 2
Film creation, UV treatment, and film evaluation were performed in the same manner as in Reference Example 1 except that SPS was changed to Zarek F2907 manufactured by Idemitsu Kosan Co., Ltd. The results are shown in Table 1.

Reference example 3
After obtaining a styrene-ethylene copolymer (EtCopoly1, Et content 5%) by the following synthesis method, film preparation, UV treatment, and film evaluation were performed in the same manner as in Reference Example 1 . The results are shown in Table 1.

  To a heat-dried 5 liter autoclave, 2,800 mL of toluene, 1.0 mmol of triisobutylaluminum (TIBA), and 412 mL of styrene were added at room temperature under a nitrogen atmosphere. After the temperature was raised to 70 ° C. with stirring, 0.07 mmol of (9-ethyl-1,2,3,4-tetrahydrofluorenyl) bis (N, N-dimethylaminobenzyl) scandium and tri-n-butylaluminum7. 0 mmol was contacted at 25 ° C., 30 minutes later, 0.084 mmol of dimethylanilinium tetrakispentafluorophenylborate was added to the contact product, and 15 minutes later, polymerization was performed for 10 minutes while maintaining the pressure at 0.09 MPa with ethylene.

  After completion of the polymerization reaction, the reaction product was put into a methanol-hydrochloric acid solution, sufficiently stirred, separated after further washing with methanol, and then dried to obtain 420 g of a styrene / ethylene copolymer. The catalytic activity was 800 kg / g Sc · hr. The molecular weight of the obtained polymer was Mw = 280,000, Mn = 117,000, Mw / Mn = 2.39, and the ethylene unit content was 5 mol%.

Example 1
In the same manner as in Reference Example 1 , SPS Zalec 90ZC was stretched to obtain a film having a thickness of 10 μm. Both surfaces of this film were subjected to UV treatment at 1000 mJ / cm ² using an ultraviolet irradiator.

Further, Toyo Ink adhesive Dynareo VA-3020 was applied to one side of this film with a bar coater at 3 g / m ² , and a laminate was prepared by pasting 50 μm of polyimide film “UPILEX” made by Mitsubishi Engineering Plastics. Pressed with temperature. Thereafter, it was aged for 4 days in a temperature atmosphere of 50 ° C.
The SPS film surface was brought into close contact with the copper plate and heat-pressed in the same manner as in Reference Example 1, and then a 100-mm grid cut was made from the polyimide film side with a cutter knife. And peeled off. The results are shown in Table 1.

Example 2
A laminate was prepared and evaluated in the same manner as in Example 1 except that a Kuraray liquid crystal polymer film “BEXTER” was used instead of the polyimide film “UPILEX”. The results are shown in Table 1.

Example 3
A laminate was prepared and evaluated in the same manner as in Example 1 except that SPS was changed to F2907. The results are shown in Table 1.

Example 4
A laminate was prepared and evaluated in the same manner as in Example 1 except that SPS was a styrene-ethylene copolymer synthesized in Reference Example 3 . The results are shown in Table 1.

Comparative Example 1
A film was prepared and evaluated in the same manner as in Reference Example 1 except that the SPS film was not subjected to UV treatment. The results are shown in Table 1.

Comparative Example 2
Instead of UV treatment, film preparation and film evaluation were performed in the same manner as in Reference Example 1 except that the SPS film surface was subjected to corona treatment at 0.6 kW and a line speed of 10 m / min. The results are shown in Table 1.

Comparative Example 3
A film was prepared and evaluated in the same manner as in Reference Example 1 except that the surface of the SPS film was subjected to nitrogen plasma treatment at 1.0 kW and a line speed of 0.5 m / min instead of UV treatment. The results are shown in Table 1.

  The syndiotactic polystyrene resin film or laminate of the present invention can be used as a coverlay film used for flexible printed boards such as electronic devices.

1 Laminated body 10 SPS film 20 Polyimide film or liquid crystal polymer film 30 Adhesive layer

Claims (4)

200 ° C., in cross-cut peeling test when the thermocompression bonding a copper plate at 50 kgf / cm 2, ¹ minute state, and are the number of squares is 20% or less was peeled to the total number of squares, syndiotactic at least one surface with ultraviolet radiation A polystyrene resin film ;
A polyimide film or a liquid crystal polymer film laminated on the syndiotactic polystyrene resin film;
A laminate comprising: The laminate according to claim 1, wherein the syndiotactic polystyrene resin is a homopolymer of styrene, a copolymer of styrene and paramethylstyrene, or a copolymer of styrene and ethylene. The laminate according to claim 1 or 2 , wherein the syndiotactic polystyrene resin film and the polyimide film or liquid crystal polymer film are laminated via an adhesive layer. The coverlay film for flexible printed bases using the laminated body in any one of Claims 1-3 .

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