JP2013206892A - High frequency substrate material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate material for use in high frequency communication and two-dimensional communication sheets, which exhibits excellent high frequency characteristics, high degree of freedom of wiring, and excellent flexibility and adhesive force, by composing the substrate material of a conductor layer, a resin layer and a resin foam layer and bonding them via sealant.SOLUTION: A high frequency substrate material having excellent high frequency characteristics of relative permittivity of 3 or less and a dielectric loss tangent of 0.01 or less, and exhibiting excellent flexibility, high degree of freedom of wiring, and excellent adhesive force is obtained by composing the high frequency substrate material at least of a conductor layer and a resin foam layer, and bonding them via sealant.

Description

The present invention provides a material for a substrate used for high-frequency communication, high-frequency wireless power feeding, an IC tag, and the like. In particular, an object is to provide a material that requires light weight and flexibility.

In recent years, communication in the high frequency band has been actively performed due to the development of communication technology represented by the Internet. Along with this, technological advances such as computer peripherals such as personal computers, servers and routers, wireless communication devices such as mobile phones, ubiquitous communication devices represented by IC tags, and wireless power supply technology as next-generation power supply means, etc. is there. As a material used in these devices, a substrate material excellent in high-frequency basic characteristics is required.

  As a printed wiring board represented by a high frequency, a material having a relative dielectric constant of 5.0 or less, preferably 3.0 or less, and a dielectric loss tangent of 0.01 or less is provided. For example, a glass base resin prepreg presented in JP2003-17821 is proposed as a printed wiring board material. This material is excellent in low dielectric constant and low dielectric loss tangent, and can form high-speed network circuits. However, it is a rigid base material such as glass. There is no.

  Moreover, a flexible base material is provided from the flexibility of a wiring board and the freedom degree of wiring. As a representative one, for example, a polyimide metal foil laminate presented in JP-A-2007-302003 is provided. Although the flexibility and flexibility of the wiring are excellent, the dielectric constant of the polyimide resin is 3.3 and the dielectric loss tangent is as high as 0.03, which is an insufficient dielectric constant characteristic as a high-frequency substrate. Further, a two-dimensional communication mode has been proposed as a communication mode of the Internet. As the structure of the communication sheet and the base material used, for example, as disclosed in JP-A-2008-160616, the upper layer is a conductor layer, the middle layer is a dielectric tangent of 0.01 or less, and the lower layer is a conductor layer It has a three-layer structure.

  As the material, the upper conductor layer is a metal layer such as copper, silver, aluminum, nickel, and the middle layer is polyethylene, polycarbonate, PET, PEN, PBT, PTT, etc. A dielectric layer of 0.01 or less, and a metal material such as copper, silver, aluminum, or nickel is used as a lower layer material. By using this material, it is a material excellent in high-frequency characteristics that can be used for high-speed communication, and has been proposed as a material that has both flexibility of wiring and flexibility as a sheet. However, the adhesive that bonds the upper layer and the middle layer requires an ester hot melt resin, nylon hot melt resin, or SBR hot melt resin, and the adhesive strength between the foam and the adhesive resin layer is low and may be easily peeled off. It was an issue.

JP 2003-17821 A JP2007-302003 JP2008-160616

The problem to be solved by the present invention is a base material having a dielectric property of a dielectric loss tangent of 0.01 or less having a dielectric constant of 3 or less, which is used as a network communication device or computer communication device represented by the Internet, and free wiring. Another object of the present invention is to provide a high-frequency base material that can be used as a flexible base material having a sufficient degree of flexibility, and in which a conductor layer and a dielectric layer, particularly a foam layer, have a sufficient and sufficient adhesive strength.

  The present invention is composed of a conductor layer and a resin foam layer, and the resin foam layer has characteristics such that the relative dielectric constant at 12 GHz is 3.0 or less and the dielectric loss tangent is 0.01 or less. The foam layer adheres via the sealant A layer.

(Resin foam layer)
If the relative dielectric constant of the resin foam layer exceeds 3.0, it is unsuitable for high-speed communication, and if the dielectric loss tangent exceeds 0.01, power loss is large. As such a resin foam layer, a resin foam selected from polyethylene, polypropylene, and poly-4-methyl-pentene-1 is preferably used because it has the above-described relative dielectric constant and dielectric loss tangent. Although there is no restriction | limiting in the expansion ratio of a foam layer, Preferably it is 1.1 to 5 times, More preferably, it is the range of 1.5 to 3 times. Although there is no restriction | limiting in the method of foaming, The well-known carbon dioxide gas foaming and the chemical foaming agent method are preferable.

(Conductor layer)
The conductor layer is preferably composed of a metal layer and a sealant B layer, and the metal layer is preferably an aluminum foil or a copper foil. It is preferable that the thickness of the conductor layer is in the range of 5 to 35 μm. Aluminum foil or copper foil is an industrially produced foil and has excellent electrical conductivity. If it is less than 5 μm, it is easy to cut when handled in a roll shape, and if it exceeds 35 μm, flexibility is lost.

(Sealant B)
The sealant B layer is preferably at least one resin layer selected from polyethylene, ethylene ionomer, and ethylene elastomer. Examples of polyethylene include linear low density polyethylene and high pressure method low density polyethylene. As the ethylene-based elastomer, those having a density of 0.89 g / cm 3 or less obtained by copolymerizing ethylene with α-olefin of about 8 to 20 mol% can be used. Ethylene ionomers are excellent in adhesion to metal layers, but since they have a high relative dielectric constant and dielectric loss tangent, they are preferably blended with polyethylene or ethylene elastomers. The relative permittivity of the sealant B layer is preferably 3.0 or less and the dielectric loss tangent is 0.01 or less. The conductor layer can be obtained by laminating a metal layer and a sealant B layer by a conventional method. Further, the conductor layer is characterized in that it is single-sided or double-sided.

(Sealant A)
The sealant A layer is preferably at least one resin layer selected from polyethylene and ethylene-based elastomer. Examples of polyethylene include linear low density polyethylene and high pressure method low density polyethylene. As the ethylene-based elastomer, those having a density of 0.89 g / cm 3 or less obtained by copolymerizing ethylene with α-olefin of about 8 to 20 mol% can be used. The sealant A layer has a role of bonding the conductor layer and the resin foam layer. That is, the structure of conductor layer / sealant A / resin foam layer, preferably metal layer / sealant B / sealant A / resin foam layer is obtained.

(Adhesive strength)
The adhesive strength between the conductor layer and the foam layer is 0.05 kN / m or more, and more preferably 0.1 kN / m or more. When laminating the conductor layer and the resin foam layer, the adhesion is strengthened by using a method in which the sealant A layer is melt-extruded, inserted between the conductor layer and the resin foam layer, and bonded, and the adhesive strength is 0.05. A laminate having kN / m or more can be obtained.

(Resin layer)
Further, a sealant B layer and a resin layer can be further provided between the metal layer and the sealant B layer. That is, the structure is metal layer / sealant B / resin layer / sealant B / sealant A / resin foam layer. The resin layer is preferably polyethylene, polypropylene, or poly-4-methyl-pentene-1 from the viewpoint of relative dielectric constant and dielectric loss tangent. As described above, the material of the sealant B positioned between the metal layer and the resin layer is preferably at least one selected from polyethylene, olefin ionomer, and ethylene elastomer. Moreover, it is preferable that the thickness of a resin layer is 5-200 micrometers, and the thickness of a resin foam layer is 100-3000 micrometers. Moreover, it is preferable that the thickness of a sealant is 1-500 micrometers.

(Protective resin layer)
Further, a protective resin layer may be provided on the surface of the conductive layer. For the protective layer, a film containing any of polyethylene, polypropylene, poly-4-methyl-pentene-1, polyester, polyacrylonitrile, ethylene-vinyl alcohol copolymer, and fluororesin can be used. Polyester is preferably polyethylene terephthalate, and the fluororesin is preferably polytetrafluoroethylene. The thickness of the protective layer is in the range of 1 to 500 μm, and it is preferable to join via a sealant. The sealant B can be used as the sealant material.

(Laminate)
An example of detailed contents of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of an example of a conductor on which both surfaces of the high-frequency substrate of the present invention are provided. 01 is a resin foam layer. 02 is a sealant. Reference numeral 03 denotes a sealant or a resin layer. 04 is a metal foil layer. 05 is a sealant, and 06 is a protective resin layer.

  FIG. 1 shows a double-sided conductor, which can be suitably used as a double-sided shield base material. Moreover, if it processes and forms the circuit of one side, it can utilize suitably as a high frequency circuit. FIG. 2 is a cross-sectional view in which one side of the high-frequency substrate of the present invention is an example of a conductor. 01 is a resin foam layer, 02 is a sealant, 03 is a resin layer or sealant, 04 is a metal foil layer, 05 is a sealant, 06 is a protective resin layer, 07 is a sealant, 08 is a sealant or resin layer, and 08 is a resin layer It is.

  FIG. 2 shows a single-sided shield base material, which can be suitably used if a micro-split line or a mesh pattern circuit used for two-dimensional communication is formed on one side of the resin layer. Although there is no restriction | limiting in the formation method of a circuit, The method of forming a circuit by screen printing using a silver paste and a copper paste is also preferable.

  FIG. 3 is an example of a high-frequency substrate having a conductor layer on both sides, a conductor layer on one side having a protective layer, and a conductor layer having no protective layer on the other side. 01 is a foam layer, 02 is a sealant, 03 is a sealant, 04 is a metal foil layer, 05 is a sealant, and 06 is a protective resin layer. If a circuit is formed by etching or machining a conductor layer without a protective layer, it can be suitably used as a high-frequency substrate. There is no limitation on the method of forming the circuit, but a dry film can be bonded to the conductor layer, a wiring pattern can be formed by light irradiation, and a circuit of the wiring pattern can be formed by etching treatment.

  By using the high frequency substrate of the present invention, a substrate having dielectric properties suitable for high frequency, flexibility and flexibility of wiring, and sufficiently high adhesion strength of each layer against bending and the like. Can be provided.

Hereinafter, the details of the present invention will be described with reference to examples.
Dielectric constant and dielectric loss tangent: Measured by the cavity resonator method. A typical frequency is 12 GHz.
Adhesive strength: The peel strength between the conductor layer and the resin foam layer was measured with Tensilon by preparing a strip having a width of 1 cm and a length of 5 cm. The measurement was performed according to JISK6854 (1999).
Example 1

(Formation of foam sheet)
Low density polyethylene made from prime polymer was used. The resin was dissolved by a single screw extruder, carbon dioxide gas was injected, and a resin foam was formed by a circulation die. The expansion ratio was 2 times, and the thickness of the foam layer was 1 mm.

(Formation of conductive layer)
A heating laminator with three-layer feeding was used. Two layers of PET / PE sealant as protective layers, each having a thickness of 12 μm and 15 μm are fed out of the roll, and the second axis is a roll of aluminum 7 μm rolled out of the roll. A 20 μm thick ethylene ionomer film was fed out. The three-layer film was laminated with a silicon rubber roll heated to 150 ° C. to form a conductor layer with a protective layer PET / PE sealant / Al / ionomer resin sealant B layer.

(Creation of base material by bonding of foam layer and conductive layer)
A biaxial paying pasting machine was used. The conductive film having a foam sheet roll on one axis and a resin layer such as a sealant bonded on the second axis was set on a roll. Low density polyethylene was used for the sealant A layer for bonding. Low-density polyethylene is extruded from a T-die with a single screw extruder, a sealant is inserted between the foam sheet and the conductor film, bonded with a laminator, and a foam sheet with a conductor on one side: PET / PE sealant B / An Al / ethylene ionomer sealant B / PE sealant A / foamed sheet was formed. The thickness of each sealant was 35 μm.

Set the resulting sheet again on one axis, set the conductor film on the second axis, extrude the polyethylene sealant from the single-axis extruder, and insert the sealant between the foam sheet of the single-sided conductor and the conductor film Then, it was bonded by a laminator to form a foam sheet: PET / PE sealant B / Al / ethylene ionomer sealant B / PE sealant A / foam sheet / PE sealant A / Al. The thickness of the sealant was 35 μm. The resulting sheet was processed, and the dielectric constant and dielectric loss tangent were measured at 12 GHz by the cavity resonance method. As a result, the dielectric constant was 1.7 and the dielectric loss tangent was 0.0007. Moreover, as a result of creating strip-shaped test pieces and measuring the peel strength between the conductor layer and the foam layer, all of them were material destruction. As a result, the substrate has excellent characteristics as a high-frequency substrate.
(Example 2)

It carried out similarly to Example 1 until preparation of the foam sheet of a single-sided conductor.
(Formation of surface resin film)
A biaxial feed heat laminator was used. A poly-4-methyl-pentene-1 film (Mitsui Chemicals Tosero Co., Ltd., Opulan film) 50 μm is set on the first axis, and a sealant PE film 30 μm is set on the second axis, at a temperature of 150 ° C. Lamination was performed with a silicone rubber roll. The resulting film was a surface resin film with a sealant.

(Creation of base material by forming single-sided conductor)
A biaxial feeding and pasting machine was used. A poly-4-methyl-pentene-1 film having a single-sided conductor foam sheet on one axis and a sealant bonded on the second axis was set. Low density polyethylene was used as the sealant for bonding. Polyethylene was extruded from a T-die with a single screw extruder, a sealant was inserted between the foamed sheet and the poly-4-methyl-pentene-1 film with sealant, and joined by a roll laminator. The thickness of the sealant was 35 μm. The base material of the foam sheet which one side is a conductor was formed. The resulting sheet was processed and measured by the cavity resonator method at a frequency of 12 GHz. As a result, the relative dielectric constant was 1.7 and the dielectric loss tangent was 0.0007. Moreover, as a result of making strip-shaped test pieces and measuring the peel strength between the conductor layer and the foam layer, all of them were material destruction. As a result, it was a substrate having excellent characteristics as a high-frequency substrate.
(Example 3)

(Formation of single-sided conductive layer)
The same operation as in Example 1 was performed.
(Formation of conductive layer without protective layer)
This was carried out with a two-axis pay-out thermal laminator facility. An aluminum foil having a thickness of 7 μm was drawn on the first axis, and an ethylene ionomer film having a thickness of 20 μm was drawn on the second axis. The two-layer film was laminated with a silicon rubber roll heated to 150 ° C. to form a conductor film with an ethylene ionomer.

(Creation of a base material by forming a double-sided conductive layer)
A biaxial feeding and pasting machine was used. Single-sided conductive foam sheet roll of Example 1 on one axis. The film of the above conductor layer was used on the second axis. Low density polyethylene was used as the sealant for bonding. Polyethylene was extruded from a T-die using a single-screw extruder, a sealant was inserted between the foamed sheet and the conductor film, and joined by a laminator to prepare a base material having both conductors. The thickness of the sealant was 35 μm. The resulting sheet was processed and measured by the cavity resonator method at a frequency of 12 GHz. As a result, the relative dielectric constant was 1.7 and the dielectric loss tangent was 0.0007. Moreover, as a result of cutting out into strip shape and performing the peeling test of a conductor layer and a resin layer, and a resin layer and a foam layer, all were material destruction. From the above result, it was the base material which has the characteristic excellent as a high frequency base material.
(Comparative Example 1)

In the same manner as in Example 1, a foam layer and a conductor film were prepared.
(Creation of a base material by joining a conductor layer and a foam layer)
A 3-axis laminator was used. Conductor layer on the 1st axis, ester-based hot melt resin (chemit film made by Toray Fine Chemicals Co., Ltd.) on the 2nd axis, foam sheet is set on the 3rd layer, and a silicon rubber roll laminator is applied at a temperature of 130 ° C. Combined. As a result of bonding, a roll-shaped base material having a conductor on one side was obtained. The resulting sheet is set on one axis again, ester hot melt resin is set on the second axis, a conductor film is set on the third axis, and heat-laminated with a silicon rubber roll laminator at 130 ° C, and both sides are conductive foam A sheet was formed. The resulting sheet was processed and measured by the cavity resonator method at a frequency of 12 GHz. As a result, the relative dielectric constant was 1.7 and the dielectric loss tangent was 0.01. The strip was cut into strips and the peel strength between the conductor layer and the foam layer was measured. As a result, the peel strength between the conductor layer and the foam layer was 0.001 kN / m.
Example 4

(Formation of single-sided conductor layer)
The same operation as in Example 1 was performed.
(Formation of conductive layer)
The same equipment as in Example 1 was used. A PET / PE sealant was used on the first axis, a 6 μm thick copper foil was used on the second axis, and an ionomer film was used on the third axis, and was laminated with a silicon rubber roll heated at a temperature of 150 ° C.
(Creation of a base material by forming a double-sided conductive layer)
It implemented like Example 2 except having used the conductive layer which laminated copper foil. The resulting sheet was processed and measured at 12 GHz by the cavity resonator method. As a result, the relative dielectric constant was 1.7. The dielectric loss tangent was 0.0007.
(Example) 5-8

Example 1 and Example 2 were performed except that the resin of the foam layer was polypropylene or poly-4-methyl-pentene-1. The results obtained are listed in Table 1.

接着強度１：導電体層と発泡体層の剥離強度

Adhesive strength 1: peel strength between conductor layer and foam layer

  The high-frequency board material of the present invention forms a microstrip line or mesh-like circuit for high-frequency board wiring, and is effectively used as a wiring board for high-frequency equipment.

Both surfaces of the high-frequency substrate of the present invention are cross-sectional views of an example of a conductor layer. One side of the high-frequency substrate of the present invention is a cross-sectional view of an example of a conductor layer Both surfaces of the high-frequency substrate of the present invention are cross-sectional views of an example of a conductor layer.

01 Resin foam layer 02 Sealant 03 Sealant 04 Metal foil layer 05 Sealant 06 Resin layer 07 Sealant 08 Sealant 09 Resin layer

Claims (10)

It is composed of at least a conductor layer and a resin foam layer, and the resin foam layer has a characteristic in which a relative dielectric constant at 12 GHz is 3 or less and a dielectric loss tangent is 0.01 or less. The conductor layer and the resin foam layer are A high-frequency substrate material which is bonded through a sealant A layer and has an adhesive strength of 0.05 kN / m or more between the conductor layer and the resin foam layer. The conductor layer is composed of a conductor and a sealant B layer, the conductor is an aluminum foil or a copper foil, the conductor thickness is in the range of 5 to 35 μm, and the sealant B layer is polyethylene, ethylene ionomer, ethylene The high-frequency substrate material according to claim 1, comprising at least one resin layer selected from elastomers. The high-frequency substrate material according to claim 2, wherein the sealant B layer has a relative dielectric constant of 3 or less and a dielectric loss tangent of 0.01 or less. The high-frequency substrate material according to claim 2 or 3, wherein a sealant B layer and a conductor layer are further laminated on the resin foam layer. 5. The method according to claim 2, wherein at least one resin layer selected from polyethylene, olefinic ionomer, polypropylene, and poly-4-methyl-pentene-1 is further laminated between the conductor layer and the sealant B layer. The high frequency substrate material described in 1. The high-frequency substrate material according to any one of claims 1 to 5, wherein the sealant A layer is at least one resin layer selected from polyethylene, polyethylene ionomer, and ethylene elastomer. The high-frequency substrate material according to claim 1, wherein the resin foam layer has a thickness of 100 to 3000 μm. The high frequency substrate material according to claim 1, wherein each sealant has a thickness of 1 to 500 μm. The high-frequency substrate material according to claim 1, further comprising a protective layer made of a resin on a surface of the conductive layer, wherein the protective layer has a thickness of 1 to 500 μm. The high frequency according to claim 9, wherein the protective layer is a film containing any one of polyethylene, polypropylene, poly-4-methyl-pentene-1, polyethylene terephthalate, polyacrylonitrile, ethylene-vinyl alcohol copolymer, and fluororesin. Board material.

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