JPH0749488B2 - Low dielectric laminate - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a laminate excellent in low dielectric property, and more particularly, to a laminate having a high strength used for a high frequency electric insulating material, particularly a radar dome, a parabolic antenna, and the like. And a low dielectric layered body having the same.

TECHNICAL BACKGROUND OF THE INVENTION AND PROBLEMS OF THE INVENTION Electrical structural materials such as radar domes and parabolic antennas are required to have high strength and low dielectric constant. Conventionally, a high-strength composite material composed of an epoxy resin and glass fiber has been used as a plastic electric structural material for a radar dome, a parabolic antenna, and the like, but this composite material has a problem of high dielectric constant. .

The inventors of the present invention have conducted extensive studies to solve the above problems, and when a laminate made of a stretched ultra high molecular weight polyolefin having high strength is used as a reinforcing material and a polyolefin is used as a matrix resin to form a laminate, high strength is obtained. It was found that a laminated body excellent in low dielectric property that can be used as the electric structure material of 1) can be obtained, and the present invention has been completed.

OBJECT OF THE INVENTION The present invention is intended to solve the problems associated with the prior art as described above, and is directed to a high frequency electrical insulating material, in particular,
An object is to provide a high-strength, low-dielectric laminate that can be used in radar domes, parabolic antennas, and the like.

SUMMARY OF THE INVENTION The low dielectric laminate according to the present invention is characterized by using an ultrahigh molecular weight polyolefin cloth as a reinforcing material and using polyolefin as a matrix resin.

Specific Description of the Invention Hereinafter, the low dielectric laminate according to the present invention will be specifically described.

Ultra high molecular weight polyolefin cloth As the ultra high molecular weight polyolefin cloth as a reinforcing material used in the present invention, specifically, high strength such as ultra high molecular weight polyolefin cloth, ultra high molecular weight polypropylene cloth, silane crosslinked ultra high molecular weight polyethylene cloth, etc. And a low dielectric cloth is used.

Ultra high molecular weight polyethylene, which is a component of the stretched material that constitutes the ultra high molecular weight polyethylene cloth, is a decalin solvent 13
Intrinsic viscosity [η] at 5 ℃ is 5dl / g or more, preferably 7
It is in the range of ~ 30dl / g. If the intrinsic viscosity is less than 5 dl / g, a stretched product having excellent tensile strength cannot be obtained even when stretched.

As a method for obtaining a stretched high molecular weight polyethylene, for example, a method as described in detail in JP-A-56-15408 and JP-A-59-187614, that is, ultrahigh molecular weight polyethylene is diluted with a dilute solution. Alternatively, a method of drawing a ultrahigh molecular weight polyethylene by adding a low molecular weight compound such as paraffin wax to the ultrahigh molecular weight polyethylene can be exemplified.

As the ultra-high molecular weight polyethylene stretched product, one having a tensile elastic modulus of 20 GPa or more, preferably 50 GPa or more and a tensile strength of 1.2 GPa or more, preferably 1.5 GPa or more is used. The tensile modulus is 50 GPa or more, and the tensile strength is
Since those having a weight of 1.5 GPa or more are lightweight and have high rigidity and high tensile strength, they are most suitable as a stretched product of ultra-high molecular weight polyethylene.

The cloth used in the present invention may be of any type of weave, and specifically, plain weave, satin weave, twill weave and the like are used.

If necessary, a cloth composed of an ultrahigh molecular weight polyethylene stretched product or an ultrahigh molecular weight polyethylene stretched product may be subjected to so-called corona discharge treatment, plasma discharge treatment, radiation (electron beam, γ-ray) irradiation treatment, ultraviolet light. Surface treatment such as irradiation treatment can be performed.

Polyolefin The polyolefin used as the matrix in the present invention is an ethylene / polycyclic olefin copolymer, a polyolefin such as methylpentene resin (TPX), or a surface-treated ethylene / polycyclic such as plasma treatment or corona treatment. A polyolefin such as an olefin copolymer or a methylpentene resin (TPX), and a polyolefin having a low dielectric constant such as a polyolefin modified by a graft reaction or a polymer reaction are used.

The ethylene / polycyclic olefin copolymer used in the present invention includes an ethylene repeating unit within the range of 40 to 90 mol% and the following general formula [I] within the range of 60 to 10 mol%.
Alternatively, a random copolymer (ethylene / polycyclic olefin copolymer) composed of a repeating unit represented by the general formula [II] is used.

(In the general formulas [I] and [II], R ^{1 to} R ¹⁰ are a hydrogen atom, a halogen atom or a hydrocarbon group and may be the same or different, and R ^{5 to} R ⁸ are repeated a plurality of times. In this case, R ^{5 to} R ⁸ may be the same or different, n and m are both 0 or a positive integer, and l is an integer of 3 or more.) This random copolymer Has an intrinsic viscosity [η] of 0.03 to 10 dl / g measured at 135 ° C in a decalin solvent, a crystallinity by X-ray diffraction of 10% or less, an iodine value of 5 or less, and a glass transition. The temperature (Tg) is preferably in the range of 50 to 250 ° C. Among them, a random copolymer having an intrinsic viscosity of 0.1 to 5 dl / g, a crystallinity of 5% or less, an iodine value of 1 or less, and a glass transition temperature of 60 to 200 ° C. Particularly preferred.

The cyclic olefin composed of the repeating unit represented by the general formula [I] can be easily produced by condensing cyclopentadiene and the corresponding olefin by the Diels-Alder reaction. Also, the cyclic olefin composed of the repeating unit represented by the general formula [II] can be easily produced by similarly condensing cyclopentadiene and the corresponding cyclic olefin by the Diels-Alder reaction.

As the monomer component capable of deriving the repeating unit represented by the general formula [I] used as the copolymerization component of the random copolymer, specifically, the compounds shown in Table 1, or 1,4,5, 8-Dimethano-1,2,3,4,4a, 5,8,8a-
In addition to octahydronaphthalene, 2-methyl-1,4,5,
8-dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthalene, 2-ethyl-1,4,5,8-dimethano-1,2,3,4,4a, 5,
8,8a-octahydronaphthalene, 2-propyl-1,4,5,
8-dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthalene, 2-hexyl-1,4,5,8-dimethano-1,2,3,4,4a,
5,8,8a-octahydronaphthalene, 2,3-dimethyl-1,
4,5,8-Dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthalene, 2-methyl-3-ethyl-1,4,5,8-dimethano-1,2, 3,4,4a, 5,8,8a-octahydronaphthalene, 2
-Chloro-1,4,5,8-dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthalene, 2-bromo-1,4,5,8-dimethano-1,2 , 3,4,4a, 5,8,8a-octahydronaphthalene, 2
-Fluoro-1,4,5,8-dimethano-1,2,3,4,4a, 5,8,8a-
Octahydronaphthalene, 2,3-dichloro-1,4,5,8-dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthalene, 2-cyclohexyl-1,4,5, 8-dimethano-1,2,3,
4,4a, 5,8,8a-octahydronaphthalene, 2-n-butyl-1,4,5,8-dimethano 1,2,3,4,4a, 5,8,8a-octahydronaphthalene, 2 -Isobutyl-1,4,5,8-dimethano-
Examples include octahydronaphthalene such as 1,2,3,4,4a, 5,8,8a-octahydronaphthalene, and the compounds shown in Table 2.

Specific examples of the monomer component capable of deriving the repeating unit represented by the general formula [II] include compounds shown in Tables 3 and 4.

The copolymer of ethylene with a monomer component capable of deriving the repeating unit represented by the general formula [I] or the general formula [II] has, for example, an amount of other than less than equimolar to ethylene within a range not impairing its properties. The monomer components may be copolymerized. Specific examples thereof include α-olefins and cyclic olefins. As α-olefins, α-olefins having usually 3 to 20 carbon atoms, preferably 3 to 10 carbon atoms, such as propylene, 1-butene and 3-methyl are included. -1-butene, 1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1
-Decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-eicosene and the like are used. Further, as the cyclic olefin, cycloolefins or styrenes having no bridge, for example, cyclopentene, cyclohexene, 3,4-dimethylcyclopentene, 3-methylcyclohexene, 2- (2-methylbutyl) -1-cyclohexene, styrene, α-methyl Styrene etc. is used,
Dicyclopentadiene, ethylidene norbornene,
Polyenes such as vinyl norbornene can be used as well. It is also possible to copolymerize unsaturated carboxylic acids such as (anhydrous) maleic acid.

Such a polymer is produced by polymerizing the monomer components as described above using a well-known Ziegler catalyst, particularly a vanadium-based Ziegler catalyst. More specifically, a prior patent application filed by the present applicant (see, for example, JP-A-60
-168708).

This random copolymer is, in addition to the above-mentioned components, within a range that does not impair the object of the present invention, for example, glass fiber, potassium titanate fiber, fibrous reinforcing agent such as carbon fiber, heat resistance stabilizer, weather resistance stabilizer, lubricant. , Nucleating agents, antistatic agents, dyes, pigments, and also inorganic powder fillers such as talc, calcium carbonate, wollastonite, mica and silica.

In the present invention, as the solvent used for dissolving the polyolefin, specifically, an organic solvent such as toluene, cyclohexane or methylcyclohexane is preferably used.

Low-Dielectric Laminate A low-dielectric laminate of the present invention is a laminate composed of an ultra-high molecular weight polyolefin cloth layer and a polyolefin layer obtained by subjecting one ultra-high molecular weight polyolefin cloth to a surface treatment with a polyolefin solution. , And a multi-layer laminate composed of two or more ultra-high molecular weight polyolefin cloths surface-treated with a polyolefin solution.

Method for producing low-dielectric laminate A low-dielectric laminate formed by subjecting one sheet of ultra-high molecular weight polyolefin cloth to a surface treatment with a polyolefin solution is prepared by dissolving polyolefin in an organic solvent such as toluene. It is manufactured by subjecting the solution to surface treatment of ultra-high molecular weight polyolefin cloth, followed by preliminary drying and press molding.

A low-dielectric laminate composed of two or more ultra-high molecular weight polyolefin cloths surface-treated with a polyolefin solution is prepared by dissolving polyolefin in an organic solvent such as toluene, It is produced by surface-treating a molecular weight polyolefin cloth, predrying it, and then stacking two or more ultrahigh molecular weight polyolefin cloths obtained by preliminary drying and press-molding them.

The surface treatment method of the ultra-high molecular weight polyolefin cloth in the low-dielectric laminate of the present invention with a polyolefin solution is, specifically, a conventionally known surface treatment method such as a coating method with a roll coater or the like, a coating method with an impregnation coating, or the like. Is used.

The press molding conditions differ depending on the type, thickness, and basis weight of the ultrahigh molecular weight polyolefin cloth used, the type of soluble polyolefin, the amount of applied resin, and the like.

EFFECTS OF THE INVENTION The low dielectric layered product according to the present invention is a layered product having an ultrahigh molecular weight polyolefin cloth as a reinforcing material and a polyolefin as a matrix resin, and has a high strength and a low dielectric constant. Therefore, the low-dielectric laminate according to the present invention is provided with a high-frequency electrical insulating material, particularly a radar dome,
It can be used for applications such as electric structure materials that are required to have high strength and low dielectric constant such as parabolic antennas.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

Example 1 First, an ethylene polycyclic olefin copolymer as a polyolefin was produced as follows, and 120 g of the obtained ethylene polycyclic olefin copolymer was dissolved in 500 ml of toluene to prepare a solution.

(Synthesis of Ethylene Polycyclic Olefin Copolymer) Ethylene and polycyclic olefin 1,4,5,8-dimethano- were continuously prepared using a glass polymerization vessel No. 2 equipped with a stirring blade.
1,2,3,4,4a, 5,8,8a-octahydronaphthalene (Structural formula: , Hereinafter, abbreviated as DMON). That is,
From the upper part of the polymerization vessel, the cyclohexane solution of DMON, the concentration of DMON in the polymerization vessel was 60 g /, and the cyclohexane solution of VO (OC ₂ H ₅ ) Cl ₂ as a catalyst, the vanadium concentration in the polymerization vessel was
0.9 mmol /, ethyl aluminum sesquichloride (Al
A cyclohexane solution of (C ₂ H ₅ ) _1.3 Cl _1.5 ) was continuously supplied to each of the polymerization vessels so that the aluminum concentration in the polymerization vessel was 7.2 mmol / min. The polymerization liquid in the vessel is continuously withdrawn so that it is always 1. Also, from the top of the polymerization vessel, ethylene
, Hydrogen at a rate of 6 and nitrogen at a rate of 45 per hour. The copolymerization reaction was carried out at 10 ° C. by circulating a refrigerant through a jacket attached outside the polymerization vessel.

When the copolymerization reaction is performed under the above conditions, a polymerization reaction mixture containing an ethylene polycyclic olefin (ethylene / DMON) copolymer is obtained. A small amount of isopropyl alcohol was added to the polymerization liquid extracted from the lower part of the polymerization vessel to stop the polymerization reaction. Then, the polymerization solution was charged into a household mixer containing about 3 times the amount of acetone with respect to the polymerization solution while rotating the mixer to precipitate the produced copolymer. The precipitated copolymer was ingested by filtration, and the polymer concentration was about 50 g /
To the boiling point of acetone and treated the copolymer for about 2 hours. After the treatment described above, the copolymer was ingested by filtration and dried under reduced pressure at 120 ° C. for 24 hours.

¹³ C-NMR of the ethylene / DMON random copolymer (ethylene polycyclic olefin copolymer) obtained as described above.
The ethylene composition in the copolymer measured by analysis is 59 mol%,
The intrinsic viscosity [η] measured in decalin at 135 ℃ is 0.42dl /
g, glass transition temperature was 136 ° C.

Next, a cloth having a basis weight of 200 g / m ² composed of an ultrahigh molecular weight polyethylene stretched product was prepared. Cross organization,
Details regarding the cloth such as weight are shown in Table 1.

The prepared cloth was coated with the toluene solution at 255 g / m ² and dried at room temperature for 10 minutes to obtain a prepreg. Six prepregs obtained in this way were laminated and
Press molding was performed for 0 minutes to obtain a laminated plate. Bending strength (JIS K 6911) and dielectric constant (A
STM D 150) was measured.

The measurement results are shown in Table 2.

Comparative Example 1 Using the ultra high molecular weight polyethylene stretched product of Example 1
Unit weight is 200g / m²87.5 parts by weight on the cross
Epoxy resin, product name "EPOMIK  R-301 M80 "(Three
Well Petrochemical Co., Ltd.) and 30 parts by weight of epoxy resin
Fat, product name "EPOMIK  R-140 "(Mitsui Petrochemical Industry
Co., Ltd.), 5 parts by weight of dicyandiamide, and 5 parts by weight
Parts of 3- (p-chlorophenyl) -1,1-dimethylure
And a mixture of 25 parts by weight of dimethylformamide.
265 g / m resin²After coating, dry at 100 ° C for 4 minutes to prepare
I got a prepreg. 6 pieces of prepreg thus obtained
Laminate the sheets, press-mold at 100 ° C for 1 hour, and stack
A layer board was obtained. About the obtained laminated board, it is the same as that of Example 1.
Then, the bending strength and the dielectric constant were measured.

The measurement results are shown in Table 2.

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Claims (3)

[Claims] 1. A low-dielectric laminate comprising an ultrahigh molecular weight polyolefin cloth as a reinforcing material and a polyolefin as a matrix resin. 2. The polyolefin comprises an ethylene repeating unit within the range of 40 to 90 mol% and a repeating unit represented by the following general formula [I] or general formula [II] within the range of 60 to 10 mol%. The low dielectric laminate according to claim 1, which is a random copolymer comprising General formula (In the general formulas [I] and [II], R ^{1 to} R ¹⁰ are a hydrogen atom, a halogen atom or a hydrocarbon group and may be the same or different, and R ^{5 to} R ⁸ are repeated a plurality of times. In this case, R ^{5 to} R ⁸ may be the same or different, n and m are both 0 or a positive integer, and l is an integer of 3 or more.) 3. The ultra high molecular weight polyolefin cloth comprises:
The low dielectric laminate according to claim 1 or 2, which is an ultrahigh molecular weight polyethylene cloth.