JPH07272801A - Coaxial cable connector - Google Patents

Abstract

PURPOSE:To provide a coaxial cable connector which exerts excellent dielectric characteristics of fluoric resin, has a low coefficient of linear expansion, presents an excellent heat resistant. mechanical, and productive properties, and uses a molding of thermoplastic fluoric resin compound as electric insulating material. CONSTITUTION:A connector for coaxial cable uses as an electric insulating material a molding of a thermoplastic fluoric resin compound containing 3-90 parts by wt. liquid crystal polyester relative to 100 parts by wt. thermoplastic fluoric resin, wherein the fluoric resin consists of a copolymer of tetrafluoroethylene and perfluoro-alkylbinylether, copolymer of tetrafluoroethylene and hexafluoropropylene, or copolymer of tetrafluoroethylene and ethylene.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coaxial cable connector using a molded product of a thermoplastic fluororesin composition as an insulator.

[0002]

2. Description of the Related Art A coaxial cable connector comprises a conductor, a center contact, a sheath, a shell, and an insulator that holds the center contact and insulates the center contact from the sheath. Insulators for coaxial cable connectors generally have a low dielectric constant because they are used under high frequencies.
For example, tetrafluoroethylene resin having a dielectric loss tangent value is used. However, in order to produce an insulator for connectors for coaxial cables made of tetrafluoroethylene resin, it is necessary to use a special molding method such as ram extrusion molding, and since it requires cutting work, it can be mass-produced. It was a disadvantage. On the other hand, as a thermoplastic fluororesin having excellent molding processability, a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether, a copolymer of tetrafluoroethylene and hexafluoropropylene, a copolymer of tetrafluoroethylene and ethylene However, the insulators for connectors for coaxial cables molded from these thermoplastic fluororesins have drawbacks such as large shrinkage during molding, poor dimensional accuracy, and large linear expansion coefficient. Therefore, in actual use, inconvenience may occur.

[0003]

DISCLOSURE OF THE INVENTION The present invention solves the above problems and maintains the excellent dielectric properties of fluororesins,
It has a low coefficient of linear expansion, excellent heat resistance, mechanical properties, and productivity.
An object of the present invention is to provide a connector for a coaxial cable using a molded product of a thermoplastic fluororesin composition as an insulator.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that by blending a specific amount of liquid crystal polyester with a thermoplastic fluororesin,
The inventors have found that an insulator molded from the resin composition has excellent suitability when used in a connector for coaxial cables, and completed the present invention. That is, the present invention is the invention described below. (1) A thermoplastic fluororesin composition containing 3 to 90 parts by weight of a liquid crystal polyester with respect to 100 parts by weight of the thermoplastic fluororesin, wherein the fluororesin is a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether. For a coaxial cable using a molded article of a thermoplastic fluororesin composition, which is a copolymer of tetrafluoroethylene and hexafluoropropylene, or a copolymer of tetrafluoroethylene and ethylene, as an insulator connector. (2) The liquid crystal polyester has the following structural units (I) and (I
I), (III), (IV), (II) /
The molar ratio of (I) is 0.2 to 1.0, [(III) +
A molar ratio of (IV)] / (II) is 0.9 to 1.1,
(IV) / (III) molar ratio is 0-1.0, The connector for coaxial cables which used the molded article of the thermoplastic fluororesin composition as described in (1) as an insulator.

[Chemical 2]

The thermoplastic fluororesin used in the present invention is a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether (perfluoroalkoxy resin; hereinafter sometimes referred to as PFA resin), tetrafluoroethylene and hexa. Copolymer with fluoropropylene (hereinafter sometimes referred to as FEP resin) or tetrafluoroethylene and ethylene (hereinafter,
Sometimes referred to as ETFE resin. ), Both of which are polymers whose main component is an olefin containing a fluorine atom. As a commercial product of PFA resin, the trade name is NEOFLON P
FA AP-210 [manufactured by Daikin Industries, Ltd.], trade name Teflon 340-J [manufactured by Mitsui DuPont Fluorochemicals Co., Ltd.] and the like can be mentioned. As a commercial product of FEP resin, trade name NEOFLON FEP NP-20 [ Daikin Industries, Ltd.], trade name Teflon 110 [Mitsui DuPont Fluorochemicals Co., Ltd.], and the like. Commercially available products of ETFE resin include trade name NEOFLON ETFE EP-
521 (manufactured by Daikin Co., Ltd.), Tefzel 200 (manufactured by Mitsui DuPont Fluorochemical Co., Ltd.) and the like.

The liquid crystal polyester used in the present invention is
A polyester called a thermotropic liquid crystal polymer, which is composed of (1) a combination of an aromatic dicarboxylic acid, an aromatic diol and an aromatic hydroxycarboxylic acid, (2) a different aromatic hydroxycarboxylic acid, (3) ) A combination of an aromatic dicarboxylic acid and an aromatic diol, (4) a polyester such as polyethylene terephthalate reacted with an aromatic hydroxycarboxylic acid, etc., and anisotropic melting at a temperature of 400 ° C. or lower. It forms the body. Incidentally, instead of these aromatic dicarboxylic acids, aromatic diols and aromatic hydroxycarboxylic acids, ester-forming derivatives thereof may be used. Examples of the repeating structural unit of the liquid crystal polyester include the following, but are not limited thereto.

Repeating structural unit derived from aromatic hydroxycarboxylic acid:

[Chemical 3]

Repeating structural unit derived from aromatic dicarboxylic acid:

[Chemical 4]

Repeating structural units derived from aromatic diols:

[Chemical 5]

[0010]

[Chemical 6]

A particularly preferred liquid crystal polyester in view of the balance of heat resistance, mechanical properties and processability is _one containing at least 30 mol% of a repeating structural unit represented by the following formula (A ₁ ).

[Chemical 7]

Specifically, the combinations of repeating structural units are preferably those represented by the following formulas (a) to (f). (A): (A ₁ ), (B ₁ ) or (B ₁ ) and (B ₂ )
A mixture of (C ₁ ). (B): (A ₁ ) and (A ₂ ). (C) in those combinations of the structural units of :( a), that replaces the part of A ₁ in A _2. (D): A combination of the structural units of (a) in which a part of B ₁ is replaced by B ₃ . (E): A combination of the structural units shown in (a) in which a part of C ₁ is replaced by C ₃ . (F): A combination obtained by adding the structural units of B ₁ and C _{1 to} the structural unit of (b). Basic structure (a), (b)
The liquid crystal polyesters described in JP-B-47-47870 and JP-B-63-3888 are described, for example. Particularly preferred liquid crystal polyesters have the structural units (I), (II), (III) and (IV)
And the (II) / (I) molar ratio is 0.2-1.
0, the molar ratio of [(III) + (IV)] / (III) is 0.9 to 1.1, and the molar ratio of (IV) / (III) is 0 to 1.0.

In the thermoplastic fluororesin composition used for the coaxial cable connector of the present invention, the mixing ratio of the liquid crystal polyester resin is preferably 3 to 90 parts by weight, and particularly preferably 100 parts by weight of the fluororesin. The mixing ratio is 10 to 70 parts by weight. When the compounding ratio of the liquid crystal polyester resin is more than 90 parts by weight, the dielectric property is deteriorated, which is not preferable. Also, when the mixing ratio of the liquid crystal polyester resin is less than 3 parts by weight, the effect of improving the dimensional accuracy is insufficient, which is not preferable.

With respect to the composition used in the present invention, glass fibers, silica-alumina fibers, wollastonite, carbon fibers, potassium titanate whiskers and the like in a fibrous or acicular shape are used within the range not impairing the object of the present invention. Reinforcing agent; Calcium carbonate, dolomite, talc, mica, clay, glass beads, and other inorganic fillers; Fluorocarbon resin and other release agents; Dyes, pigments, and other colorants; Antioxidants;
One or more usual additives such as a heat stabilizer, an ultraviolet absorber, an antistatic agent and a surfactant can be added. Further, a small amount of thermoplastic resin, for example, polyamide, polyester, polyphenylene sulfide, polyether ketone, polycarbonate, polyphenylene ether and modified products thereof, polysulfone, polyether sulfone,
It is also possible to add a small amount of a thermosetting resin such as polyetherimide, for example, one or more of phenol resin, epoxy resin, polyimide resin and the like.

The mixing means of the raw material components for obtaining the resin composition used for the coaxial cable connector of the present invention is not particularly limited. Thermoplastic fluororesin and liquid crystal polyester resin, if necessary reinforcing agents such as glass fibers and inorganic fillers, release improvers, heat stabilizers, etc. are mixed using a Henschel mixer, tumbler, etc., and then an extruder is used. It is preferable to use and melt-knead. The shape of the connector for coaxial cable using the molded product of the thermoplastic fluororesin composition of the present invention as an insulator is not particularly limited, and a known shape can be used. For example, a pair of plug and jack connectors as shown in FIG. 1 can be cited. Center contact 3,6
Are held by the insulators 2 and 5, and the insulators 1 and 4
Hold. A connector for a coaxial cable using the molded article of the thermoplastic fluororesin composition of the present invention as an insulator,
It can be used for connection of a coaxial cable used in a communication device used in the VHF band and the UHF band, a microwave communication equipment such as radio and television broadcasting, an information device, and radar. Coaxial cable connectors are not only 3 GHz, which has been widely used up to now, but also 11 GHz, as well as precision coaxial connectors for measuring equipment, due to the increase in frequency used due to the spread of high frequency communication and the diversification of information in recent years. Then, there are some that are used at about 30 GHz, and the dielectric characteristics at higher frequencies tend to be emphasized. The thermoplastic fluororesin composition used for the coaxial cable connector of the present invention can be used at the same time as a coating material for the cable portion of the coaxial cable.

[0016]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited thereto. The measurements and tests of various physical properties in the examples were carried out by the following methods. (1) Molding shrinkage: A flat plate-shaped test piece having a size of 64 mm square and a thickness of 3 mm was molded, and the molding shrinkage in the flow direction was measured. (2) Linear expansion coefficient: ASTM No. 4 dumbbell was molded, the center of the neck portion was cut out, and the linear expansion coefficient in the flow direction was measured using a thermomechanical analyzer. (3) Tensile strength: ASTM No. 4 tensile dumbbell is molded,
It was measured according to ASTM D638.

(4) Flexural modulus, deflection temperature under load (hereinafter sometimes referred to as TDUL): length 127 mm,
A test piece having a width of 12.7 mm and a thickness of 6.4 mm was molded and measured according to ASTM D790 and ASTM D648, respectively. (5) Dielectric property evaluation: For measurement at 1 MHz, a disk-shaped test piece having a diameter of 100 mm and a thickness of 1.6 mm was molded and measured in accordance with JIS K6911.
For measurement at 9 GHz, a disk-shaped test piece having a diameter of 75 mm and a thickness of 1.6 mm was molded, and a cavity resonator method using a TE ₀₁₁ mode using a network analyzer 8510 and 8515A (manufactured by Hewlett Packard) was used. It was measured by. (6) Flow temperature: Melt viscosity of 48,000 poise measured by a method of extruding a resin heated at a temperature rising rate of 4 ° C./min through a nozzle having an inner diameter of 1 mm and a length of 10 mm under a load of 100 kgf / cm ^2. Temperature to show.

Examples 1 to 4 and Comparative Examples 1 to 2 NEOFLON PFA AP- which is a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether.
210 [manufactured by Daikin Industries, Ltd.] and the repeating structural unit consists of the above-mentioned (I), (II), (III) and (IV), and (I) :( II) :( III) :( IV). Has a molar ratio of 60: 20: 15: 5 and a flow temperature of 323 ° C.
The liquid crystal polyester resin having the composition shown in Table 1 was mixed with a Henschel mixer and then granulated at a cylinder temperature of 360 ° C. using a twin-screw extruder (PCM-30 type manufactured by Ikegai Tekko KK) to give a fluororesin composition. I got a thing.

The pellets obtained are from Nissei Plastic Industry Co., Ltd.
Cylinder temperature of 37 using PS40E5ASE type manufactured by
Injection molding is performed at 0 ° C and a mold temperature of 180 ° C.
No. dumbbells, bending test pieces, and test pieces for molding shrinkage evaluation, and using these, tensile strength by the above method,
The flexural modulus, molding shrinkage, linear expansion coefficient, and dielectric properties were measured. The results are shown in Table 1.

The thermoplastic fluororesin compositions (Examples 1 to 4) containing the liquid crystalline polyester resin of the present invention show extremely low molding shrinkage and linear expansion coefficient, and have excellent heat resistance and mechanical properties. At the same time, it retained the excellent dielectric constant and dielectric loss tangent of the PFA resin.

In addition, when the compounding amount of the liquid crystal polyester is less than 3 parts by weight (Comparative Examples 1 and 2), the effect of reducing the molding shrinkage and the linear expansion coefficient is not sufficient, and the compounding amount of the liquid crystal polyester resin is 90. If it exceeds the weight part (Comparative Example 3),
The values of dielectric constant and dielectric loss tangent increased.

[0022]

[Table 1]

[0023]

The coaxial cable connector of the present invention comprises:
A molded product of a thermoplastic fluororesin composition, which retains the excellent dielectric properties of a fluororesin, has a low linear expansion coefficient, and has excellent heat resistance, mechanical properties, and productivity, is used as an insulator. Cable connectors are VHF band, UHF
It can be suitably used for connecting a coaxial cable used in a communication device used in a band, a radio communication equipment such as radio and television broadcasting, an information device, and a radar.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a coaxial cable connector of the present invention.

[Explanation of symbols]

 1. Exterior (shell). 2. Insulator. 3. Center contact (conductor). 4. Exterior (shell). 5. Insulator. 6. Center contact (conductor).

Claims (2)

[Claims] 1. A thermoplastic fluororesin composition containing 3 to 90 parts by weight of a liquid crystalline polyester with respect to 100 parts by weight of a thermoplastic fluororesin, wherein the fluororesin is a mixture of tetrafluoroethylene and perfluoroalkyl vinyl ether. Coax using a molded article of a thermoplastic fluororesin composition, which is a polymer, a copolymer of tetrafluoroethylene and hexafluoropropylene, or a copolymer of tetrafluoroethylene and ethylene, as an insulator Cable connector. 2. A liquid crystal polyester comprising the following structural units (I), (II), (III) and (IV),
The molar ratio of (II) / (I) is 0.2 to 1.0, [(I
The molar ratio of (II) + (IV)] / (II) is 0.9 to
1.1, the molar ratio of (IV) / (III) is 0 to 1.0
A connector for a coaxial cable using the molded article of the thermoplastic fluororesin composition according to claim 1 as an insulator. [Chemical 1]