Liquid-crystalline polymer blend and composition comprising the same
The present invention provides a liquid-crystalline polymer blend which is obtained by combining liquid-crystalline polymer (A) which has a modulus of elongation of 20-32 GPa and a melting point measured by differential scanning calorimeter of 250-330° C. and liquid-crystalline polymer (B) which has a melting point measured by differential scanning calorimeter of equal to or higher than 190° C. and lower than 250° C., wherein the weight ratio of said liquid-crystalline polymer (A) to said liquid-crystalline polymer (B) is in the range of from 50:50 to 90:10. The liquid-crystalline polymer blend and the liquid-crystalline polymer blend composition comprising the same exhibit good mechanical properties such as modulus of elongation and good molding processability at low temperatures. The liquid-crystalline polymer blend and the liquid-crystalline polymer blend composition of the present invention are suitable for producing welded articles with high joint strength.
1. A liquid-crystalline polymer blend, which is obtained by combining:
(A) a liquid-crystalline polymer which has a modulus of elongation of 20-32 GPa and a melting point measured by differential scanning calorimeter of 250-330° C., and
(B) a liquid-crystalline polymer which has a melting point measured by differential scanning calorimeter of equal to or higher than 190° C. and lower than 250° C.,
wherein, the weight ratio of said liquid-crystalline polymer (A) to said liquid-crystalline polymer (B) is in the range of from 50:50 to 90:10.
2. The liquid-crystalline polymer blend according to claim 1 , wherein the polymer blend has a melting point measured by differential scanning calorimeter of equal to or higher than 200° C. and lower than 250° C.
3. The liquid-crystalline polymer blend according to claim 1 , wherein the liquid-crystalline polymer (A) comprises 50-80 mol % of the repeating unit represented by the following formula (I) in the total repeating units of the polymer (A)
4. The liquid-crystalline polymer blend according to claim 3 , wherein the liquid-crystalline polymer (A) consists of the following repeating units:
wherein,
Ar 1 and Ar 2 each represent at least one bivalent aromatic group;
X represents O or NH; and
a, b and c represent relative molar portion (mol %) of the repeating units in the liquid-crystalline polymer (A) and satisfy the following formulae:
50 mol %≦ a≦ 80 mol %
10 mol %≦ b≦ 25 mol %
10 mol %≦ c≦ 25 mol %
a+b+c= 100 mol %.
5. The liquid-crystalline polymer blend according to claim 4 , wherein Ar 1 and Ar 2 represent paraphenylene group and X represents NH.
6. The liquid-crystalline polymer blend according to claim 1 , wherein the liquid-crystalline polymer (B) consists of the following repeating units:
wherein,
Ar 3 and Ar 4 each represent at least one bivalent aromatic group; and
p, q, r and s represent relative molar portion (mol %) of the repeating units in the liquid-crystalline polymer (B) and satisfy the following formulae:
0.4≦ q/p≦ 2.0
2 mol %≦ r≦ 15 mol %
2 mol %≦ s≦ 15 mol %
p+q+r+s= 100 mol %.
7. The liquid-crystalline polymer blend according to claim 6 , wherein the liquid-crystalline polymer (B) consists of the following repeating units:
wherein,
the number lower right of the repeating unit represents mol % of each repeating unit in the liquid-crystalline polymer (B).
8. A liquid-crystalline polymer blend composition comprising at least one inorganic and/or organic filler in an amount of 0.1-200 parts by weight per 100 parts by weight of the liquid-crystalline polymer blend according to claim 1 .
9. The liquid-crystalline polymer blend composition according to claim 8 , wherein the inorganic and/or organic filler is glass fiber.
10. A molded article obtainable by molding a liquid-crystalline polymer blend, which is obtained by combining:
(A) a liquid-crystalline polymer which has a modulus of elongation of 20-32 GPa and a melting point measured by differential scanning calorimeter of 250-330° C., and
(B) a liquid-crystalline polymer which has a melting point measured by differential scanning calorimeter of equal to or higher than 190° C. and lower than 250° C.,
wherein the weight ratio of said liquid-crystalline polymer (A) to said liquid-crystalline polymer (B) is in the range of from 50:50 to 90;10, or
a composition comprising said liquid-crystalline polymer blend.
11. The molded article according to claim 10 , which is a cross-flow fan or a component thereof.
12. The molded article according to claim 11 , wherein the cross-flow fan or the component thereof has a thin wall part whose thickness is equal to or less than 0.8 mm.
13. A method for manufacturing a molded article with a joint comprising the step of joining more than one components obtained by molding
a liquid-crystalline polymer blend, which is obtained by combining:
(A) a liquid-crystalline polymer which has a modulus of elongation of 20-32 GPa and a melting point measured by differential scanning calorimeter of 250-330° C., and
(B) a liquid-crystalline polymer which has a melting point measured by differential scanning calorimeter of equal to or higher than 190° C. and lower than 250° C.,
wherein, the weight ratio of said liquid-crystalline polymer (A) to said liquid-crystalline polymer (B) is in the range of from 50:50 to 90:10, or a composition comprising said liquid-crystalline polymer blend,
wherein, the joining step is carried out by ultrasonic welding, vibration welding, high-frequency welding, electromagnetic induction welding, impulse welding or spin welding.
14. The method according to claim 13 , wherein the molded article is a cross-flow fan or a component thereof.