JPH0253840A - Composition having low permittivity - Google Patents

Abstract

PURPOSE:To provide the subject composition composed of a fibrous molecular- oriented molded article of a specific ultra-high-molecular weight ethylene.alpha-olefin copolymer and a matrix resin and having light weight, high strength and excellent weather-resistance, heat-resistance, etc. CONSTITUTION:The objective composition is produced by (1) adding a solvent or diluent to an ultra-high-molecular weight ethylene.alpha-olefin copolymer having an intrinsic viscosity [eta] of >=5dl/g (preferably 7-30dl/g) and a >=3C alpha-olefin content of 0.1-20 units (preferably 0.5-10 units) per 1000C atoms on an average, (2) melting and kneading the mixture and drawing by using a liquid medium to obtain a fibrous molecular-oriented molded article of an ultra-high-molecular weight ethylene.alpha-olefin copolymer, (3) forming the molded article into a cloth, etc., and (4) coating 30-90vol.% of the cloth with 70-10vol.% of a thermoplastic resin or a thermosetting resin as a matrix resin to form a prepreg.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. The present invention relates to a low dielectric composition, and more particularly, to a fibrous molecularly oriented molded article of an ultra-high molecular weight ethylene/α-olefin copolymer, and a matrix. The present invention relates to a low dielectric composition composed of a resin, which is lightweight, has high strength, has excellent weather resistance and heat resistance, and has low dielectric property.

Circuit boards, parabolic antennas, radar domes, etc. are required to have a low dielectric constant, be extremely lightweight, and have high strength. Circuit boards tend to be required to have properties such as heat resistance and water resistance, and parabolic antennas and radar domes are required to have properties such as weather resistance and water resistance.

By the way, as matrix resin for circuit boards, conventionally,
Polyesters such as polyethylene terephthalate are known, but this polyethylene terephthalate has a problem of being somewhat inferior in heat resistance or water resistance.

Composite materials made of epoxy resin and glass fiber have traditionally been used for parabolic antennas or radar domes, but parabolic antennas or radar domes made of these composite materials are heavy and have a relatively low dielectric constant. Moreover, there were many points that needed improvement in terms of mechanical strength.

The present inventors conducted extensive research to solve the above-mentioned problems, and found that a composition comprising an oriented fibrous molecule of an ultra-high molecular weight ethylene/α-olefin copolymer and a matrix resin was found to be excellent. The present invention was completed based on the discovery that it has the following characteristics.

It is already known that a molecularly oriented molded article having high elastic modulus and high tensile strength can be obtained by forming ultra-high molecular weight polyethylene into fibers, tapes, etc. and stretching the fibers. For example, in Japanese Patent Application Laid-Open No. 56-15408,
It is described that a dilute solution of ultra-high molecular weight polyethylene is spun from 1 to 1 and the resulting filament is drawn. Further, JP-A No. 59-130313 describes melt-kneading ultra-high molecular weight polyethylene and wax, extruding the kneaded product, cooling and solidifying it, and then stretching. describes that the above melt-kneaded product is extruded, drafted, cooled and solidified, and then stretched.

The present invention attempts to solve the problems associated with the conventional technology as described above, and is lightweight, has excellent mechanical strength, weather resistance, water resistance, and heat resistance, and has low heat resistance. The object is to provide a low dielectric composition that is dielectric.

The low dielectric composition according to the present invention has an intrinsic viscosity [η] of at least 5 dl/g, and an average content of α-olefins having 3 or more carbon atoms of 0.5 dl/g per 1000 carbon atoms. 1
It is characterized by consisting of a fibrous molecule-oriented body of an ultra-high molecular weight ethylene/α-olefin copolymer having ~20 molecules, and a matrix resin.

The low dielectric composition according to the present invention is composed of a fibrous molecular oriented body of the ultra-high molecular weight ethylene/α-olefin copolymer as described above and a matrix resin, and is lightweight and has high strength. It has excellent weather resistance, water resistance, and heat resistance, and also has low dielectric property.

The low dielectric composition according to the present invention will be specifically explained below.

First, a fibrous molecularly oriented molded article of an ultra-high molecular weight ethylene/α-olefin copolymer constituting the low dielectric composition according to the present invention will be described.

The fibrous molecularly oriented molded product used in the present invention is a fibrous molecularly oriented molded product of an ultra-high molecular weight ethylene/α-olefin copolymer.

The ultra-high molecular weight ethylene/α-olefin copolymer constituting the molecularly oriented molded article of the present invention includes ultra-high molecular weight ethylene/propylene copolymer, ultra-high molecular weight ethylene/1-butene copolymer, ultra-high molecular weight ethylene・4-methyl-1-
Pentene copolymers, ultra-high molecular weight ethylene/1-hexene copolymers, ultra-high molecular weight ethylene/1-octene copolymers, ultra-high molecular weight ethylene/1-decene copolymers, etc. in which ethylene and carbon atoms are α of 20, preferably 4 to 10
-Ultra high molecular weight ethylene/α-olefin copolymers with olefins can be exemplified. This ultra-high molecular weight ethylene/α-olefin copolymer has α-olefins with 3 or more carbon atoms.
- The olefin is 0.00% per 1000 carbon atoms of the polymer.
It is contained in an amount of 1 to 20 pieces, preferably 0.5 to 10 pieces, and more preferably 1 to 7 pieces.

Fibrous molecularly oriented molded products obtained from such ultra-high molecular weight ethylene/α-olefin copolymers have particularly excellent impact resistance and creep resistance compared to molecularly oriented molded products obtained from ultra-high molecular weight polyethylene. ing. This ultra-high molecular weight ethylene/α-olefin copolymer is lightweight, has high strength, and has excellent abrasion resistance, impact resistance, and creep resistance, as well as excellent weather resistance and heat resistance.

The ultra-high molecular weight ethylene/α-olefin copolymer constituting the molecularly oriented molded product of the present invention has an intrinsic viscosity [η] of 5
dl/g or more, preferably in the range of 7 to 30 dJ/g, and the fibrous molecularly oriented molded product obtained from this copolymer has excellent mechanical properties and heat resistance. In other words, molecular terminals do not contribute to fiber strength, and the number of molecular terminals depends on the molecular weight (
Since it is the reciprocal of the intrinsic viscosity [η], a material with a large intrinsic viscosity [η] gives high strength.

The density of the fibrous molecularly oriented molded product used in the present invention is 0.
．． 94.0-0.990g/cd preferably 0.960
~0.985 g/cJ. Here, the density is calculated by the usual method (A
STHD 1505), it was measured by the density gradient tube method. The density gradient tube at this time was prepared by using carbon tetrachloride and toluene, and the measurement was performed at room temperature (23° C.).

The dielectric constant (I
KHz, 23°C) is 1.4 to 3.0, preferably 1.8
〜2,4, and the positive electric loss tangent (IKHz=80℃) is 0
．． 05-0.008% preferably 0.040-o, oi
o%. Here, the dielectric constant and positive electric dissipation tangent are determined by closely aligning fibers and tape-like molecular oriented bodies in one direction.
Measurement was performed using ASTH0150 using a sample made into a film.

The stretching ratio of the fibrous molecularly oriented molded article used in the present invention is 5 to 80 times, preferably 10 to 50 times.

The degree of molecular orientation in the fibrous molecularly oriented molded article used in the present invention can be determined by an X-ray diffraction method, a birefringence method, a fluorescence polarization method, or the like. The molecular orientation degree of the fibrous molecularly oriented molded product used in the present invention is, for example, as described by Yukichi Go and Teru Kubo:
The degree of orientation according to the half-width, which is described in detail in the Industrial Chemistry Magazine Vol. The degree of orientation (F) defined as the value width (°) is 0.90 or more, especially 0.9
From the viewpoint of mechanical properties, it is desirable that the molecules be oriented so that the number of particles is 5 or more.

Furthermore, the fibrous molecularly oriented molded product used in the present invention is
As mentioned above, it has excellent mechanical properties, for example, in the form of a drawn filament, it has a pressure of 20 GPa or more, especially 30 GPa.
an elastic modulus of a or more and 1.2 GPa or more, especially 1.5 GPa
It has a tensile strength of a or more.

The impulse voltage breakdown value of the fibrous molecularly oriented molded product used in the present invention is 110 to 250 KV/Sono, preferably 15
0-220 KV/mm. The impulse voltage breakdown value was measured by using the same sample as in the case of dielectric constant, using a brass (25+wy+φ) JIS type electrode on a copper plate, and increasing the voltage while applying a negative impulse in steps of 2KV/3 times.

The fibrous molecularly oriented molded article used in the present invention is characterized by extremely excellent impact resistance, breaking energy, and creep resistance. The characteristics of these molecularly oriented molded products of ultra-high molecular weight ethylene/α-olefin copolymers are expressed by the following physical properties.

The breaking energy of the fibrous molecularly oriented molded product of the ultra-high molecular weight ethylene/α-olefin copolymer used in the present invention is 8 kg-m7g or more, preferably 10 kg-m7g or more.

Furthermore, the fibrous molecularly oriented molded product of the ultra-high molecular weight ethylene/α-olefin copolymer used in the present invention has excellent creep resistance. In particular, it has outstanding creep resistance at high temperatures, which corresponds to the conditions that promote creep at room temperature.
℃, and the creep determined as elongation (%) after 90 seconds is 7% or less, especially 5% or less, and furthermore, from 90 seconds to 18
The creep rate after 0 seconds (e, 5ec-1) is 4×1
0sec or less, special 5 x 10-"sec -'
It is as follows.

The molecularly oriented ultrahigh molecular weight ethylene/α-olefin copolymer used in the present invention has the above-mentioned room temperature properties, but in addition to these room temperature properties, it also has the following thermal properties: If it is, the above-mentioned room temperature physical properties are further improved and heat resistance is also excellent, which is preferable.

The fibrous molecularly oriented molded product of the ultra-high molecular weight ethylene/α-olefin copolymer used in the present invention has at least one crystalline structure heated to a temperature at least 20°C higher than the original crystal melting temperature ('ran) of the copolymer. It has a crystal melting peak (Tp), and the heat of fusion based on this crystal melting peak (Tp) is
It accounts for 15% or more, preferably 20% or more, especially 30% or more of the total heat of fusion of the polymer.

The original crystalline melting temperature ('ran) of the ultra-high molecular weight ethylene/α-olefin copolymer is determined by completely melting the molded product, cooling it, relaxing the molecular orientation in the molded product, and then raising the temperature again. It can be determined by a second run using a so-called differential scanning calorimeter.

To explain further, in the fibrous molecularly oriented molded product used in the present invention, there is no crystal melting peak at all in the above-mentioned crystal melting temperature range inherent to the copolymer, or even if it exists, it exists only slightly as a tailing. It's just a matter of doing.

The crystal melting peak (Tp) is generally within the temperature range Tm+2
0℃~Tl11+50℃, especially Tm+20℃~Tl+1
It is usually expressed in the 00° C. region, and this peak (Tp) often appears as a plurality of peaks within the above temperature range. That is, this crystal melting peak (Tp
) is the temperature range Tl-1-35℃~TI'Il+10
The melting peak on the high temperature side ('rp 1) at 0°C and the melting peak on the low temperature side (TO2) in the temperature range Tn++208C to Tn++35°C are often separated and appear depending on the manufacturing conditions of the molecularly oriented molded product. , TO and TI)2 may further consist of a plurality of peaks.

These high crystal melting peaks ('rp,'rp2)
is thought to significantly improve the heat resistance of molecularly oriented molded products of ultra-high molecular weight ethylene/α-olefin copolymers and contribute to strength retention or elastic modulus retention after high-temperature thermal history. It will be done.

Further, it is desirable that the sum of the heat of fusion based on the high temperature side melting peak ('rp1) in the temperature range T111+35°C to T+n+100°C is 1.5% or more, particularly 3.0% or more based on the total heat of fusion.

Furthermore, as long as the sum of the heat of fusion based on the high-temperature side melting peak ('rp1) satisfies the above-mentioned value, if the high-temperature side melting peak ('rp1) does not stand out as a main peak, in other words, it is a small peak. Even if it becomes an aggregate or a broad peak, the heat resistance may be slightly lost, but the creep resistance is excellent.

The melting point and heat of crystal fusion in the present invention were measured by the following method.

The melting point was determined using a differential scanning calorimeter as follows.

As the differential scanning calorimeter, a DSCn type (manufactured by PerkinElmer) was used. The sample was restrained in the orientation direction by wrapping approximately 3 mm around an aluminum plate measuring 4'mm x 4 and having a thickness of 0.2 mm. Next, the sample wrapped around an aluminum plate was sealed in an aluminum pan and used as a measurement sample. Additionally, the empty aluminum pan that is usually placed in the reference holder was filled with the same aluminum plate used for the sample to maintain heat balance. First, the sample was held at 30°C for about 1 minute, then at 10°C.
The temperature was raised to 250° C. at a temperature increase rate of /min, and the melting point measurement at the first temperature increase was completed. Continue at 250℃ for 10
The sample was held at 30°C for 10 minutes, then the temperature was lowered at a rate of 20°C/min, and the sample was held at 30°C for 10 minutes. Then, the second temperature was raised to 250 °C at a temperature increase rate of 10 °C/min,
At this time, the melting point measurement during the second temperature increase (second run) was completed. At this time, the maximum value of the melting peak was taken as the melting point. When it appears as a shoulder, a tangent is drawn at the inflection point immediately on the low-temperature side and the inflection point immediately on the high-temperature side of the shoulder, and the intersection is taken as the melting point.

In addition, the straight line (
Draw a perpendicular line to the point 20°C higher than the original crystalline melting temperature (T1) of the ultra-high molecular weight ethylene copolymer, which is determined as the main melting peak during the second temperature rise (baseline), and the area on the low temperature side surrounded by these. is based on the crystalline melting (TIl) inherent in the ultra-high molecular weight ethylene copolymer, and the high temperature side part is based on the crystalline melting (TIl) that exhibits the function of the molded article of the present invention.
Tp), and the heat of fusion of each crystal is
Calculated from these areas. Also, Tpl and Tp2
The heat of fusion based on the melting of Tn+2
Similarly, the part surrounded by the perpendicular line from 0°C and the perpendicular line from Tl-1-35°C is the heat of fusion based on the melting of Tp2, and the high temperature side part is the heat of fusion based on the melting of Tpl. Calculated.

The fibrous molecularly oriented molded product of the ultra-high molecular weight ethylene/α-olefin copolymer used in the present invention, such as a drawn filament, has a strength retention rate of 95% or more after being subjected to a heat history of 5 minutes at 170°C. , elastic modulus retention rate of 90% or more,
In particular, it has an excellent heat resistance of 95% or more, which is completely unrecognizable in conventional drawn polyethylene filaments.

Method for producing a molecularly oriented molded product of ultra-high molecular weight polyolefin A method for producing a molecularly oriented molded product of an ultra-high molecular weight ethylene/α-olefin copolymer having high elasticity and high tensile strength as described above is, for example, disclosed in Japanese Patent Application Laid-Open No. 1983-1993. 15408 Publication 1, JP-A-58-5228, JP-A-51-130313
The ultra-high molecular weight ethylene/α-olefin copolymer is made into a dilute solution, or the ultra-high molecular weight ethylene/α-olefin copolymer is made into By adding low molecular weight compounds such as paraffin wax, ultra-high molecular weight ethylene/α-
A method for improving the stretchability of an olefin copolymer and stretching it to a high ratio can be exemplified.

Ultra-high molecular weight ethylene/α-olefin copolymer 4 Next, to make it easier to understand, we will explain the method for producing a molecularly oriented molded product of ultra-high molecular weight ethylene/α-olefin copolymer.
The raw materials, manufacturing method, and purpose will be explained below in order.

Raw Materials The ultra-high molecular weight ethylene/α-olefin copolymer used in the present invention is produced by slurry polymerizing ethylene and an α-olefin having 3 or more carbon atoms using a Ziegler catalyst, for example, in an organic solvent. can get.

As the α-olefin having 3 or more carbon atoms, propylene,
butene-1, pentene-1,4-methylpentene-1,
Hexene-1, heptene-1, octene-1, etc. are used, and among these, butene-1,4-methylpentene-1, hexene-1, octene-1, etc. are particularly preferred.

Such α-olefins are copolymerized with ethylene in the amount stated above per 1000 carbon atoms of the resulting copolymer. Further, the ultra-high molecular weight ethylene/α-olefin copolymer used as a base when producing the molecularly oriented product in the present invention should have a molecular weight corresponding to the above-mentioned intrinsic viscosity [η].

The α-olefin component in the ultra-high molecular weight ethylene/α-olefin copolymer used in the present invention is determined using an infrared spectrophotometer (manufactured by JASCO Corporation). Specifically, the absorbance of 1378an-1, which represents the bending vibration of the methyl group of an α-olefin incorporated into the ethylene chain, was measured using an infrared spectrophotometer, and this value was determined in advance by 13C nuclear magnetic resonance. Using the equipment, quantify the amount of α-olefin in the ultra-high molecular weight ethylene/α-olefin copolymer by converting it into the number of methyl branches per 1000 carbon atoms using a calibration curve created using a model compound. .

1. In the present invention, when producing a molecularly oriented material from the ultra-high molecular weight ethylene/α-olefin copolymer, a diluent is added to the copolymer. As such a diluent, a solvent for the ultra-high molecular weight ethylene copolymer or various wax-like substances having compatibility with the ultra-high molecular weight ethylene copolymer can be used.

Such a solvent has a boiling point higher than the melting point of the copolymer, more preferably 20°C higher than the melting point of the copolymer.
A solvent having a boiling point higher than that is used.

Specifically, such solvents include n-nonane, n-
- Decane, n-undecane, n-dodecane, n-tetradecane, n-octadecane or liquid paraffin, aliphatic hydrocarbon solvents such as kerosene, xylene, naphthalene,
Tetralin, butylbenzene, p-cymene, cyclohexylbenzene, diethylbenzene, pentylbenzene,
Aromatic hydrocarbon solvents such as dotesylbenzene, bicyclohexyl, decalin, methylnaphthalene, ethylnaphthalene or hydrogenated derivatives thereof, 1,1,2.2-tetrachloroethane, pentachloroethane, hexachloroethane, 1.2.3 Examples include halogenated hydrocarbon solvents such as -trichloropropane, dichlorobenzene, L2,4-trichlorobenzene, and bromobenzene, and mineral oils such as paraffinic process oils, naphthenic process oils, and aromatic process oils.

Further, as the wax as a diluent, specifically, an aliphatic hydrocarbon compound or a derivative thereof is used.

Such aliphatic hydrocarbon compounds are mainly composed of saturated aliphatic hydrocarbon compounds, and are usually compounds called paraffin waxes having a molecular weight of 2,000 or less, preferably 1,000 or less, more preferably 800 or less.

Specifically, such aliphatic hydrocarbon compounds include n-alkanes having 22 or more carbon atoms such as tocosan, tricosane, tetracosane, and triacontane, mixtures of these with lower alkanes as main components, and petroleum-derived n-alkanes. Separated and purified so-called paraffin wax, medium and low pressure polyethylene wax, which is a low molecular weight polymer obtained by copolymerizing ethylene or ethylene with other α-olefins, high pressure polyethylene wax, ethylene copolymer wax, or medium and low pressure polyethylene wax, ethylene copolymer wax, and Used are waxes whose molecular weight is lowered by thermal degradation of polyethylene such as low-pressure polyethylene and high-pressure polyethylene, oxides of these waxes, oxidized waxes modified with maleic acid, waxes modified with maleic acid, and the like.

Examples of aliphatic hydrocarbon compound derivatives include, for example, one or more carboxyl groups, preferably one to two carboxyl groups, particularly preferably one carboxyl group, at the terminal or inside of an aliphatic hydrocarbon group (alkyl group, alkenyl group), A compound having a functional group such as a hydroxyl group, a carbamoyl group, an ester group, a meltcapto group, or a carbonyl group, with a carbon number of 8 or more, preferably a carbon number of 12 to 50, or a molecular weight of 130 to 2,000.
Preferably, 200 to 800 fatty acids, aliphatic alcohols, fatty acid amides, fatty acid esters, aliphatic mercaptans, aliphatic aldehydes, aliphatic ketones, etc. are used.

Examples of such aliphatic hydrocarbon compound derivatives include fatty acids such as capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, and oleic acid, lauric alcohol, myristyl alcohol, cetyl alcohol, and stearyl alcohol. Fatty acid amides such as caprinamide, lauramide, palmitinamide, and stearylamide, fatty acid esters such as stearyl acetate, and the like are used.

The ultra-high molecular weight ethylene/α-olefin copolymer and diluent differ depending on their type, but - 3 for boat fishing
:97-80:20, especially 15:85-60:
A weight ratio of 40 is used. If the amount of the diluent is lower than the above range, the melt viscosity will become too high, making melt kneading and melt molding difficult, and the resulting molded product will have a markedly rough surface and is prone to stretch breakage. On the other hand, if the amount of the diluent is larger than the above range, melt-kneading will become difficult, and the resulting molded product will have poor stretchability.

Melt kneading is generally carried out at 150-300°C, particularly at 170-200°C.
It is carried out at a temperature of 70°C. If the temperature is lower than the above range, the melt viscosity will be too high and melt molding will be difficult, and if the temperature is higher than the above range, the molecular weight of the ultra-high molecular weight ethylene/α-olefin copolymer will decrease due to thermal degradation. death,
It becomes difficult to obtain a molded article having excellent high elastic modulus and high strength. The blending may be carried out by dry blending using a Henschel mixer, type 1 blender, or the like, or by using a single-screw extruder or a multi-screw extruder.

Melt molding of a dope (spinning stock solution) comprising an ultra-high molecular weight ethylene/α-olefin copolymer and a diluent is generally performed by melt extrusion molding. Specifically, filaments for drawing are obtained by melt extruding the dope through a spinneret.

At this time, the molten material extruded from the spinneret may be drafted, that is, drawn in the molten state. ■ Extrusion speed of molten resin in the die orifice. The draft ratio can be defined by the following formula:

Draft ratio -v/vo (2) This draft ratio varies depending on the temperature of the mixture, the molecular weight of the ultra-high molecular weight ethylene copolymer, etc., but is usually 3 or more, preferably 6 or more. can.

Next, the ultra-high molecular weight ethylene α obtained in this way
- Stretching the unstretched molded olefin copolymer. Stretching is carried out so as to effectively impart at least uniaxial molecular orientation to the unstretched molded article obtained from the ultra-high molecular weight ethylene/α-olefin copolymer.

Stretching of an unstretched molded article obtained from an ultra-high molecular weight ethylene/α-olefin copolymer is generally carried out at a temperature of 40 to 160°C, particularly 80 to 145°C. Air,
Either water vapor or liquid medium can be used. However, as a heat medium, a liquid medium that is a solvent capable of eluting and removing the diluent described above and whose boiling point is higher than the melting point of the molded article composition, specifically, decalin, decane, kerosene, etc., is used. It is preferable to carry out the stretching operation in such a manner that the diluent described above can be removed, uneven stretching will not occur during stretching, and a high stretching ratio can be achieved.

The means for removing the diluent from the ultra-high molecular weight ethylene/α-olefin copolymer is not limited to the above-mentioned method, but may include a method of treating an unstretched material with a solvent such as hexane, heptane, hot ethanol, chloroform, or benzene, and then stretching it; A stretched product with high elastic modulus and high strength can also be obtained by removing the diluent in the molded product by treating the stretched product with a solvent such as hexane, heptane, hot ethanol, chloroform, or benzene.

The stretching operation can be performed in one stage or in multiple stages of two or more stages. The stretching ratio depends on the desired molecular orientation and the associated effect of increasing the melting temperature, but is generally between 5 and 5.
80 times, preferably 10 to 50 times.

In general, it is preferable to carry out the stretching operation in two or more stages, and in the -th stage, the stretching operation is carried out while extracting the diluent in the extrudate at a relatively low temperature of 80 to 120°C. From the second stage onward, it is preferable to stretch the molded body at a temperature of 120 to 160°C and at a temperature higher than the first stage stretching temperature.

In the case of a uniaxial stretching operation, tension stretching may be performed between rollers having different circumferential speeds.

The fibrous molecularly oriented molded product thus obtained can be heat-treated under constrained conditions, if desired. This heat treatment is generally carried out at 140-180°C, preferably at 150-170°C.
It can be carried out at a temperature of 5° C. for 1 to 20 minutes, preferably 3 to 10 minutes.

By heat treatment, the crystallization of the oriented crystal part progresses further, the crystal melting temperature shifts to the high temperature side, the strength and elastic modulus improve,
Furthermore, creep resistance at high temperatures is improved.

The low dielectric composition according to the present invention comprises a fibrous molecularly oriented molded product of such an ultra-high molecular weight ethylene/α-olefin copolymer and a matrix resin.

If necessary, the fibrous molecularly oriented molded product of ultra-high molecular weight polyolefin or the fibrous molecularly oriented molded product of ultra-high molecular weight ethylene/α-olefin copolymer may be subjected to so-called corona discharge treatment before mixing with the matrix resin. Surface treatment such as plasma discharge treatment, radiation (electron beam, gamma ray) irradiation treatment, ultraviolet irradiation treatment, etc. can be performed in advance.

In the present invention, a thermoplastic resin and a thermosetting resin are used as the matrix resin.

Specifically, the thermoplastic resin includes polyethylene, polypropylene, ethylene/α-olefin copolymer, poly4-methyl-pentene-1, polyacrylate, polymethyl methacrylate, polyvinyl chloride, polyvinylidene chloride, polystyrene, Poly-p-xylylene, polyester, polyamide, etc. are used. In addition, ethylene
As the α-olefin copolymer, for example, an ethylene/polycyclic olefin copolymer is preferably used. unit and
Random copolymer (ethylene/polycyclic olefin copolymer) consisting of repeating units represented by the following general formula [I] or general [II] within the range of 60 to 10 mol%
etc. are used.

(In general formulas [I] and [II], R1-R10 are
They are hydrogen atoms, halogen atoms, or hydrocarbon groups, and may be the same or different, and when R5-R8 are repeated multiple times, these R5-R8 may be the same or different, respectively.

Both n and m are 0 or a positive integer, and 1
is an integer greater than or equal to 3. ) This random copolymer has an intrinsic viscosity [η] of 0.03 to 10 dj/g measured in a decalin solvent at 135°C, a crystallinity of 10% or less by X-ray diffraction, and an iodine value of 5 or less, and the glass transition temperature (TG) is 50
It is preferably within the range of ~250°C. Among these, the intrinsic viscosity [η] is 0.1 to 5 dl/g, the crystallinity is 5% or less, the iodine value is 1 or less, and the glass transition temperature is within the range of 60 to 200°C. Particularly preferred are random copolymers.

Further, as the thermosetting resin, specifically, epoxy resin, unsaturated polyester resin, alkyd resin, phenol resin, urea resin, melamine resin, xylene/formaldehyde resin, etc. are used. Among these, epoxy resins and unsaturated polyester resins are preferred.

In a low dielectric composition comprising an oriented fibrous molecule of an ultra-high molecular weight ethylene/α-olefin copolymer and a matrix resin as described above, the volume content of the oriented fibrous molecule is preferably 30 to 90%. is 50 to 80%, and the volume content of the matrix resin is 10 to 70%, preferably 20 to 50%. The dielectric constant of a molded product made of this composition is 3.9 or less, preferably 3.4 or less.

Methods for preparing such compositions include a method in which oriented fibrous molecules are aligned crosswise or in one direction and then coated with a matrix resin to form a prepreg; Preferably, it may be cut into 3 to 10 marks and mixed into the matrix resin.

The low dielectric composition according to the present invention is molded into a desired shape such as a circuit board, parabolic antenna, or radar dome by a conventional method.

Two circuit boards manufactured from the low dielectric composition of the present invention as described above are lightweight and have high strength, have excellent heat resistance and water resistance, and have low dielectric properties. Further, parabolic antennas or radar domes manufactured from the above-described low dielectric compositions are lightweight and strong, have excellent weather resistance and water resistance, and have low dielectric properties.

The low dielectricity composition according to the present invention is composed of the above-mentioned fibrous molecularly oriented body of the ultra-high molecular weight ethylene/α-olefin copolymer and a matrix resin, and is lightweight and has high properties. It is strong, has excellent weather resistance and heat resistance, and has low dielectric properties.

EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples.

Polymerization of ultra-high molecular weight ethylene-butene-1 copolymer〉 Using a Ziegler-based tactile system, n-decane 1. Slurry polymerization of an ultra-high molecular weight ethylene-butene-1 copolymer was carried out using 1.1 l as a polymerization solvent. A mixed monomer with a molar ratio of ethylene and butene-1 of 97.2:2.35 was continuously supplied to the reactor so as to maintain a constant pressure of 5 kg/cd. Polymerization was completed in 2 hours at a reaction temperature of 70°C.

The yield of the obtained ultra-high molecular weight ethylene-butene-1 copolymer powder was 160 g, and the intrinsic viscosity [η] (tecarin:
135° C.) was 8.2 dj/f, and the butene-1 content by infrared spectrophotometer was 1.5 per 1000 carbon atoms.

Preparation of stretched and oriented ultra-high molecular weight ethylene/butene-1 copolymer> 20 parts by weight of the ultra-high molecular weight ethylene/butene-1 copolymer powder obtained by the above polymerization and paraffin wax (melting point -69°C, molecular weight -490) and 80 parts by weight was melt-spun under the following conditions.

Add 3.5 parts by weight of the mixture e as a process stabilizer to 1100 parts by weight.
-Did-ert-butyl-4-hydroxytoluene 0
．． 1 part by weight was added. Next, the mixture was melt-kneaded using a screw extruder (screw diameter = 25 m+n, L/D = 25, manufactured by Thermoplastics) at a set temperature of 190°C. Subsequently, the mixed melt was melt-spun using a spinning die with an orifice diameter of 2 mm attached to the extruder. The extrusion melt was taken off at a draft ratio of 36 times with an air gap of 180 cm, cooled and solidified in air, and undrawn fibers were obtained. Furthermore, the undrawn fibers were drawn under the following conditions.

Two-stage stretching was performed using a Godetstrol made by Ohdai. At this time, the heat medium in the first drawing tank is n-decane, and the temperature is 1
The heating medium in the second drawing tank was triethylene glycol, and the temperature was 145°C. The effective length of each tank was 50 an. During the stretching, the rotational speed of the first godetroll was set at 0.5 m/min and the rotational speed of the third godetroll was changed to obtain oriented fibers with a desired drawing ratio. The rotation speed of the second godet roll is
It was appropriately selected within a range that allows stable stretching. Almost all of the initially mixed paraffin wax was extracted into n-decane during stretching. Thereafter, the oriented fibers were washed with water, dried under reduced pressure at room temperature overnight, and then subjected to measurement of various physical properties. Note that the stretching ratio was calculated from the rotational speed ratio of the first godet roll and the third godet roll.

Measurement of tensile properties> The elastic modulus and tensile strength were measured at room temperature (23° C.) using a DO350M tensile tester manufactured by Shimadzu Corporation.

At this time, the sample length between the clamps is 1ooIII! 1, and the tensile rate was 1100 rn/min (100%/min strain rate). The elastic modulus was calculated using the slope of the tangent at the initial elastic modulus. The fiber cross-sectional area required for calculation is based on the density of 0.960g/
It was calculated from the weight as cc.

Tensile modulus and strength retention after heat history The heat history test was conducted by leaving the material in a gear oven (Perfect Oven, manufactured by Tabai Seisakusho).

The sample had a length of about 3 m, and was folded over a stainless steel frame equipped with a plurality of pulleys at both ends to fix both ends of the sample. At this time, both ends of the sample were fixed to the extent that the sample did not sag, and no tension was actively applied to the sample. The tensile properties after the thermal history were measured based on the description of the measurement of the tensile properties described above.

Measurement of creep resistance〉 Creep resistance was measured using a thermal stress strain measuring device TMA/881.
0 (manufactured by Seiko Electronics Co., Ltd.), the sample length was 1 cm, the ambient temperature was 70° C., and the load was accelerated at a weight equivalent to 30% of the breaking load at room temperature. In order to quantitatively evaluate the amount of creep, the following two values were determined. That is,
Creep elongation (%) after 90 seconds after applying a load to the sample
These are the value of CR9° and the value of the average creep rate (sec'') ε after 180 seconds have elapsed from the time when 90 seconds have elapsed.

Table 1 shows the tensile properties of the multifilament obtained by bundling a plurality of drawn and oriented fibers.

Table 1 The original crystal melting peak of ultra-high molecular weight ethylene-butene-1 copolymer drawn filament (Sample-1) is 126.7
°C, and the ratio of Tp to the total crystal melting peak area was 33.8%. In addition, the creep resistance is CR9o=
There was 3.1%, ε=3.03Xio'5ec-1te. The elastic modulus retention after heat history at 170 °C for 15 minutes was 1.02.2%, and the strength retention was 102.
5%, and no deterioration in performance due to thermal history was observed.

Also, the amount of work required to break the drawn filament is 10.
3 kg-m/g, and the density is 0.973 g/cd
=, the dielectric constant is 2.2, and the dielectric loss tangent is 0502
4%, and the impulse voltage breakdown value is 180 KV
/ mm.

Next, a composition consisting of the drawn and oriented fibers of the ultra-high molecular weight ethylene-butene-1 copolymer prepared by the above method and a matrix resin was prepared by the following method, and then a molded plate was prepared.

First, the above-mentioned ultra-high molecular weight ethylene-butene-1 copolymer drawn fibers were treated with a treatment energy of 75 W/rr? using a corona discharge device (manufactured by Tomoe Kogyo ■). Corona discharge treatment was performed continuously at a treatment speed of 50 m/l/min and a treatment speed of 50 m/l/lin. When the oxygen content on the fiber surface after treatment was analyzed by varnish strength, it was found to be an average of 10 per 100 carbon atoms. In addition, the tensile properties of the fibers after corona discharge treatment, tensile strength after heat history, retention of elastic modulus, creep resistance, electrical properties such as dielectric constant, dielectric loss tangent, and impulse voltage breakdown value are all measured values as described above. It was equivalent to

The thus obtained corona discharge treated ultra-high molecular weight ethylene-butene-1 copolymer drawn fibers were
It was cut into mm.

Next, add epoxy resin (base resin, product name) to POHL.
The cut fibers were mixed with a mixed resin of R-140J manufactured by Mitsui Petrochemical Industries ■) and a curing agent ■ (formerly known as rEPO, manufactured by Q-640J Mitsui Petrochemical Industries ■) in a weight ratio of 10:6. The mixture was placed in a stainless steel beaker at a ratio of 40.2:59.8 and stirred uniformly to obtain a composition.

Using this composition, a molded plate with a thickness of 2 bars and a fiber volume content of 65% was prepared by press molding at 80°C for 2 hours, and the laminate bending strength test method (JIS K 691
1) Bending strength and dielectric constant (AST
M D 150) was measured.

The measurement results are shown in Table 2.

Polymerization of ultra-high molecular weight ethylene/octene-1 copolymer> Slurry polymerization of ethylene was carried out using a Ziegler catalyst and n-decane 11 as a polymerization solvent.

At this time, 125 ml of octene-1 as a comonomer was added.
Also, 4ONml of hydrogen for molecular weight adjustment was added all at once before starting the polymerization. Ethylene gas was continuously supplied to the reactor to maintain a constant pressure of 5 kg/Cl+, and the polymerization was completed at 70°C for 2 hours. The yield of the obtained ultra-high molecular weight ethylene/octene-1 copolymer powder was 178 g, and its intrinsic viscosity [η (decalin, 135°C) was 10.666 J/g. -1 comonomer content was 0.5 per 1000 carbon atoms.

Preparation of drawn and oriented ultra-high molecular weight ethylene/octene-1 copolymer and its physical properties> A drawn and oriented fiber was prepared by the method described in Example 1. Table 3 shows the tensile properties of the multifilament obtained by bundling a plurality of drawn and oriented fibers.

Hair L-9 The original crystal melting peak of the ultra-high molecular weight ethylene/octene-1 copolymer drawn filament (Sample-2) was 132.
1°C, and the ratios of Tp and Tpl to the total crystal melting peak area were 97.7% and 5.0%, respectively. The cleaving resistance of sample-2 is CR=2.0%, E
-9,50x10"" There was 5ec-1te. ,t
After thermal history at 170'C for 15 minutes, the elastic modulus retention was 1.08.2%, and the strength retention was 102.1%. Furthermore, the amount of work required to break sample-2 is 10.1
kg-m7g, density is 0.971g/cIa, dielectric constant is 2.2, dielectric loss tangent is 0.031%,
The impulse voltage breakdown value was 185 KV/mm.

The ethylene/octene-1 copolymer drawn fibers prepared as described above were subjected to corona discharge treatment in the same manner as in Example 1. The oxygen content analysis value based on the varnish force on the fiber surface after treatment was an average of 10.3 carbon atoms per 100 carbon atoms. Tensile properties and heat resistance of fibers after corona discharge treatment
The electrical property values were equivalent to the values before the above-mentioned treatment.

This corona discharge-treated ultra-high molecular weight ethylene/octene-1 copolymer drawn fiber was cut into 15 mm long fibers, a composition was prepared in the same manner as in Example 1, and a molded plate was prepared. , bending strength, and dielectric constant were measured.

The measurement results are shown in Table 4.

6-Issei Table-j 47.6 parts by weight of glass fiber chopped strand (trade name: Glasslon Chopped Strand GR-3-3A, manufactured by Asahi Fiber Karasu ■), the epoxy resin base material and curing agent used in Example 1 After uniformly mixing 52.4 parts by weight of the mixture, a molded plate was prepared in the same manner as in Example 1, and the bending strength and dielectric constant were measured.

The measurement results are shown in Table 5.

Claims (1)

[Scope of Claims] 1) A superorganism having an intrinsic viscosity [η] of at least 5 dl/g and an average content of α-olefins having 3 or more carbon atoms of 0.1 to 20 per 1000 carbon atoms. A low dielectric composition comprising a fibrous molecularly oriented molded product of a high molecular weight ethylene/α-olefin copolymer and a matrix resin. 2) α-olefin is butene-1,4-methylpentene-1, hexene-1, octene-1 or decene-1
The low dielectric composition according to claim 1. 3) The low dielectric composition according to claim 1, wherein the content of α-olefin is on average 0.5 to 10 per 1000 carbon atoms.