Wholly aromatic liquid crystal polyester resin molded product
View Patent ↗A molded product of a wholly aromatic liquid crystal polyester resin composition having a dielectric constant of 3.0 or less and a dielectric dissipation factor of 0.04 or less and is obtained by an injection molding of a composition comprising 90 to 45 percent by weight of the wholly aromatic liquid crystal polyester having a melting point of 320C or more, 10 to 40 percent by weight of an inorganic spherical hollow material having an aspect ratio of 2 or less, and 0 to 15 percent by weight of an inorganic filler having an aspect ratio of 4 or more. The molded product has dielectric properties suitable for information and telecommunications equipment, and is excellent in solder heat resistance, processability, and dimensional stability. The molded product is advantageous as a substrate material for use in information and telecommunications equipment such as a cellular mobile phone and as a fixing/holding member of a transmitter-receiver element.
1. A molded product comprising a dielectric constant of 3.0 or less and a dielectric dissipation factor of 0.04 or less obtained by the injection molding of a wholly aromatic liquid crystal polyester resin composition which comprises 45 to 90 percent by weight of a wholly aromatic liquid crystal polyester having a melting point of 320° C. or more, 10 to 40 percent by weight of an inorganic spherical hollow material having an aspect ratio of 2 or less, and 0 to 15 percent by weight (100 percent by weight as a total) of an inorganic filler having an aspect ratio of 4 or more, and wherein the apparent viscosity of the liquid crystal polyester at a temperature of 20° C. above the melting point of the liquid crystal polyester is 5,000 poise or less, and wherein the fracture rate X of the inorganic spherical hollow material is 0.045 to 0.094 using the following equation:
ρ=100/[α/ρ1+β/ρ2+γ(1 −X )/ρ3 +γX /ρ4], where in the equation:
α=the percent by weight of the wholly aromatic liquid crystal polyester resin;
β=the percent by weight of the inorganic filler having an aspect ratio of 4 or more;
γ=the percent by weight of the inorganic spherical hollow material having an aspect ratio of 2 or less;
ρ=the specific gravity of the wholly aromatic liquid crystal polyester resin composition;
ρ1=the specific gravity of the wholly aromatic liquid crystal polyester resin;
ρ2=the specific gravity of the inorganic filler having an aspect ratio of 4 or more;
ρ3=the true specific gravity of the inorganic spherical hollow material having an aspect ratio of 2 or less;
ρ4=the material specific gravity of the inorganic spherical hollow material;
X=the fracture rate of the inorganic spherical hollow material;
γ(1−X)=the percent by weight of non-fractured inorganic spherical hollow material;
γX=the percent by weight of fractured inorganic spherical hollow material.
2. The molded product according to claim 1 , wherein said wholly aromatic liquid crystal polyester is prepared by the polycondensation of 80 to 100 percent by mole of p-hydroxy benzoic acid (I), terephthalic acid (II), and 4,4′-dihydroxy
diphenyl (III) (including the derivatives) (provided that the total of (I) and (II) is more than 60 mole percent) and 0 to 20 percent by mole of other aromatic compound which can conduct a decondensation reaction with any one of (I), (II), or (III).
3. The molded product according to claim 1 , wherein the above mentioned inorganic spherical hollow material having an aspect ratio of 2 or less is an average particle diameter of 5 to 200 μm, and a rate of volume hollowness of 50 percent or more.
4. The molded product according to claim 1 , wherein the inorganic filler having an aspect ratio of 4 or more is a glass fiber having an average diameter of 20 μm or less and/or talc having an average particle diameter of 100 μm or less and additionally the weight percent is in a range of 5 to 15.
5. The molded product according to claim 1 , wherein the molded product comprises a portion having a thickness of 0.5 mm or less and comprising a relative dielectric constant of said portion of 3 or less.
6. The molded product according to claim 1 , comprising a portable wireless telecommunications equipment having said molded product as a fixing or a holding member of a transmitting and receiving component.
7. The molded product according to claim 2 , wherein:
the above mentioned inorganic spherical hollow material having an aspect ratio of 2 or less is an average particle diameter of 5 to 200 μm, and a rate of volume hollowness of 50 percent or more; and
the inorganic filler having an aspect ratio of 4 or more is a glass fiber having an average diameter of 20 μm or less and/or talc having an average particle diameter of 100 μm or less and additionally the weight percent is in a range of 5 to 15.
8. The molded product according to claim 7 , comprising:
a portion of the molded product having a thickness 0.5 mm or less and comprising a relative dielectric constant of said portion of 3 or less; and
a portable wireless telecommunications equipment having said molded product as a fixing or a holding member of a transmitting and receiving component.