JP2007238936A - Liquid-crystalline polymer composition, method for producing the same, molded article using the same and plane connector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid-crystalline polymer composition not only capable of reducing the formation of warp at molding but also capable of reducing the formation of the warp at high-temperature treatment after molding. <P>SOLUTION: The liquid-crystalline polymer composition in a suitable practical form contains a first liquid-crystalline polymer having ≥200°C load-deflection temperature and a second liquid-crystalline polymer having <200°C load-deflection temperature. The contents of the first and second liquid-crystalline polymers are 30-95 mass% and 5-70 mass% respectively based on the total mass thereof. The second liquid-crystalline polymer has ≥270°C and <400°C melting point and ≥270°C flow-starting temperature. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid crystalline polymer composition, a method for producing the same, and a molded article and a planar connector using the composition.

  For electronic parts such as printed boards, semiconductors, connectors, relays, switches, etc., many thermoplastic resins having excellent moldability are used. In particular, electronic parts used for surface mounting are required to have excellent heat resistance and strength in addition to moldability, and a liquid crystalline polymer is used as a material that satisfies these requirements. For this liquid crystalline polymer, various attempts have been made to improve various properties in order to make it applicable to various uses.

  For example, in order to improve the moldability of the liquid crystalline polymer, a method for improving the fluidity of the liquid crystalline polymer by adding various materials is known. Specifically, a method of adding an oligomer of p-hydroxybenzoic acid to a liquid crystal polymer (Patent Document 1), a method of blending a liquid crystal polymer with a low molecular weight liquid crystal polymer (Patent Documents 1 and 2), different melting points (Patent Document 3) and the like for mixing a liquid crystal polyester resin having s.

  Further, in recent years, electronic components have been reduced in size and thickness, and for liquid crystalline polymers used in electronic components, particularly connectors, while maintaining excellent fluidity, heat resistance and mechanical strength, There is a demand for reducing the occurrence of warpage in molded articles.

  Examples of the liquid crystalline polymer that can reduce the occurrence of warping include a liquid crystalline polyester resin filled with glass fibers so that the number average fiber length is 0.12 to 0.25 mm (Patent Document 4), liquid crystal A fibrous polymer and a granular filler added to a functional polymer (Patent Document 5), and a combination of two liquid crystal polymers having different flow temperatures and a fibrous and / or plate-like inorganic filler (Patent) Document 6) and the like are disclosed.

Further, even when forming a thinner molded product, excellent heat resistance and fluidity can be obtained, and as a liquid crystalline polymer that can further reduce warpage of the molded product, a predetermined condition is applied to a predetermined liquid crystalline polyester. The thing (patent document 7) which added the fibrous inorganic filler and plate-shaped inorganic filler which satisfy | fill is also disclosed. In addition, a liquid crystal polymer composition having specific properties such as a melting point, a glass transition temperature, and a viscosity is also known as a liquid crystalline polymer capable of improving rigidity while sufficiently maintaining fluidity (Patent Document 8). ).
Japanese Patent Laid-Open No. 3-252457 Japanese Patent No. 2823873 JP 2002-249647 A Japanese Patent No. 3045065 JP 2000-178443 A Japanese Patent Laid-Open No. 10-219085 JP 2002-294038 A JP-A-2005-298772

  However, in recent years, since further refinement of processing of electronic parts and the like has been demanded, a liquid crystalline polymer composition capable of further reducing warpage has been demanded in order to satisfy such a demand.

  In addition, molded products of liquid crystalline polymers are often subjected to solder reflow treatment when used for surface mounting, so for liquid crystalline polymer compositions not only reduce warping during molding, It is required that warpage during high-temperature processing after molding can be sufficiently reduced.

  Therefore, the present invention has been made in view of such circumstances, and not only can sufficiently reduce the occurrence of warpage during molding, but also can reduce the occurrence of warpage during high-temperature processing after molding. It is an object to provide a functional polymer composition. Another object of the present invention is to provide a method for producing such a liquid crystalline polymer composition, and a molded article and a planar connector using the liquid crystalline polymer.

  In order to achieve the above object, the liquid crystalline polymer composition of the present invention includes a first liquid crystalline polymer having a deflection temperature under load of 200 ° C. or higher and a second liquid crystalline polymer having a deflection temperature under load of less than 200 ° C. The first liquid crystalline polymer and the second liquid crystalline polymer are contained in the total mass of 30 to 95% by mass and 5 to 70% by mass, respectively, and the second liquid crystalline polymer Has a melting point of 270 ° C. or higher and lower than 400 ° C., and has a flow start temperature of 270 ° C. or higher.

Here, the “liquid crystalline polymer” in the present invention refers to a so-called thermotropic liquid crystalline polymer that exhibits liquid crystallinity when melted. In addition, the “deflection temperature under load” of the liquid crystalline polymer is determined by measuring a test piece having a length of 127 mm, a width of 12.7 mm, and a thickness of 6.4 mm using the liquid crystalline polymer according to a method in accordance with ASTM D648. , By measuring with a load of 18.6 kg / cm ² . Further, the “melting point” of the liquid crystal polymer is a melting point observed by differential scanning calorimetry (DSC) at a heating rate of 10 to 25 ° C./min. Furthermore, the “flow start temperature” is a sample in which a sample is filled in a capillary rheometer equipped with a die having an inner diameter of 1 mm and a length of 10 mm, and a load of 9.8 MPa (100 kg / cm ² ) is applied to the sample. This is the temperature at which a melt viscosity of 4800 Pa · s (48000 poise) was obtained by measuring the melt viscosity using a flow tester while extruding the sample at 4 ° C./min.

  According to the liquid crystalline polymer composition of the present invention having the above configuration, it has excellent fluidity during molding, less warpage during molding, and further reduces warpage during high-temperature processing after molding. Can do. Furthermore, according to such a liquid crystalline polymer composition, not only excellent heat resistance can be obtained, but also mechanical strength such as bending properties (bending strength, bending elastic modulus) of the molded body can be improved. Such an effect is not necessarily clear, but one of the two liquid crystalline polymers has one having a high deflection temperature under 200 ° C. and the other having a lower deflection temperature under this temperature. This is considered to be due to having appropriate liquid crystal properties as a whole by combining them as having a predetermined melting point and a predetermined flow start temperature.

  In the liquid crystalline polymer composition of the present invention, the first liquid crystalline polymer has a monomer unit derived from an aromatic hydroxycarboxylic acid, a monomer unit derived from an aromatic diol, and a monomer unit derived from an aromatic dicarboxylic acid. It is preferable. Since such a liquid crystalline polymer has a rigid molecule and high liquid crystallinity, including the first liquid crystalline polymer further reduces the fluidity, heat resistance and occurrence of warpage during molding. Can do.

  The second liquid crystalline polymer preferably contains an ester bond that bonds the structural units constituting the polymer. By so doing, it is possible to further reduce the occurrence of warpage during molding or during high-temperature processing after molding.

  Furthermore, it is more preferable that the second liquid crystalline polymer has a melting point of 295 ° C. or higher and lower than 400 ° C. By including the second liquid crystalline polymer having such a melting point, it is possible to further reduce the occurrence of warpage during high-temperature processing after molding.

  The second liquid crystalline polymer is at least one selected from the group consisting of a monomer unit having a 1,3-phenylene skeleton, a monomer unit having a 2,3-phenylene skeleton, and a monomer unit having a 2,3-naphthalene skeleton. The monomer unit is preferably contained in an amount of 10 to 45 mol%.

  All the skeletons of these monomer units have a bent structure. Since the second liquid crystalline polymer has such a monomer unit at the predetermined ratio, the second liquid crystalline polymer includes a bent structure in the molecule, and the liquid crystallinity (anisotropy) is appropriately reduced. . Therefore, by including such a second liquid crystalline polymer, the anisotropy of the liquid crystalline polymer composition can be reduced more favorably, and warpage during molding and after molding can be further reduced. It becomes possible to suppress.

  Furthermore, it is more preferable that the first liquid crystalline polymer contains all the monomer units of the second liquid crystalline polymer. By doing so, the compatibility of both at the time of melting or the like is improved, and the anisotropy of the entire liquid crystalline polymer composition is further reduced. As a result, warpage of the molded product is further reduced.

  Furthermore, the liquid crystalline polymer composition preferably contains the first liquid crystalline polymer and the second liquid crystalline polymer in the form of a powder having an average particle diameter of 1 mm or less. As a result, the first and second liquid crystalline polymers are more uniformly mixed in the liquid crystalline polymer composition, and the reduction of anisotropy and thus the reduction of warpage can be more effectively achieved.

  More specifically, the second liquid crystalline polymer is preferably obtained by solid-phase polymerization of a powdery prepolymer having an average particle size of 1 mm or less. Such a second liquid crystalline polymer can satisfactorily reduce the anisotropy of the liquid crystalline polymer composition.

  Moreover, it is more preferable that the liquid crystalline polymer composition of the present invention further contains an organic filler or an inorganic filler. By further including an organic filler or an inorganic filler, generation of warpage is further suppressed.

  Furthermore, the liquid crystalline polymer composition of the present invention preferably has a deflection temperature under load of 220 ° C. or more as a whole composition. Such a liquid crystalline polymer composition is extremely excellent in heat resistance, so that it can be applied to high-temperature treatment such as reflow, and warpage is further reduced.

  The present invention also provides a molded article comprising the liquid crystalline polymer composition of the present invention. A planar connector is suitable as such a molded product. Since such a molded product is obtained by molding the liquid crystalline polymer of the present invention, the warpage is small even if it is originally mounted on a substrate or the like and subjected to solder reflow or the like. Small and excellent in shape stability during reflow.

  The method for producing a liquid crystalline polymer composition of the present invention is a first method in which a powdery first prepolymer having an average particle diameter of 1 mm or less is solid-phase polymerized and a deflection temperature under load is 200 ° C. or higher. A step of obtaining a liquid crystalline polymer and a powdery second prepolymer having an average particle diameter of 1 mm or less are solid-phase polymerized, and the deflection temperature under load is less than 200 ° C., and the melting point is 270 ° C. or more and less than 400 ° C. And a step of obtaining a second liquid crystalline polymer having a flow start temperature of 270 ° C. or higher, and a step of mixing the first liquid crystalline polymer and the second liquid crystalline polymer. To do. By such a production method, the liquid crystalline polymer composition of the present invention can be produced satisfactorily. In the production method of the present invention, it is more preferable to obtain a second liquid crystalline polymer having a melting point of 295 ° C. or higher and lower than 400 ° C.

  According to the present invention, it is possible to provide a liquid crystalline polymer composition that can not only sufficiently reduce the occurrence of warpage during molding but also reduce the occurrence of warpage during high-temperature processing after molding, and a method for producing the same. Is possible. In addition, according to the present invention, it is possible to provide a molded product, particularly a planar connector, obtained by using such a liquid crystalline polymer composition and having less warpage due to high-temperature treatment after molding.

Hereinafter, preferred embodiments of the present invention will be described.
[Liquid Crystalline Polymer Composition]

  First, the liquid crystalline polymer composition according to a preferred embodiment will be described. The liquid crystalline polymer composition includes a first liquid crystalline polymer having a deflection temperature under load of 200 ° C. or higher and a second liquid crystalline polymer having a deflection temperature under load lower than that. Hereinafter, each of the first and second liquid crystalline polymers will be described.

  The first liquid crystalline polymer is a thermotropic liquid crystalline polymer that exhibits liquid crystallinity when melted, and is a polymer having a deflection temperature under load of 200 ° C. or higher, preferably 220 ° C. or higher. The melting point of the first liquid crystalline polymer is not particularly limited. That is, it may be an amorphous material in which the melting point is not observed, or may have a crystal structure in which the melting point is observed. Further, the glass transition temperature (Tg) of the first liquid crystalline polymer is not particularly limited, but it is more preferable that Tg is not observed as the first liquid crystalline polymer.

  Examples of the first liquid crystalline polymer include wholly aromatic polyester, aromatic-aliphatic polyester, wholly aromatic poly (ester-amide), aliphatic polyazomethine, and aromatic polyester-carbonate. Fully aromatic polyesters or wholly aromatic poly (ester-amides) are preferred because they tend to provide excellent heat resistance.

  Of these, wholly aromatic polyesters are preferred from the viewpoint of reducing the water absorption of the liquid crystalline polymer composition and reducing the dimensional change during molding and the like. Here, “fully aromatic” means that substantially all monomer units constituting the polymer have an aromatic ring (preferably a benzene ring), more specifically, in all monomer units, 50% or more, more preferably 80% or more is in a state having an aromatic ring.

  Examples of the wholly aromatic polyester suitable as the first liquid crystalline polymer include those having a monomer unit derived from an aromatic hydroxycarboxylic acid, a monomer unit derived from an aromatic diol, and a monomer unit derived from an aromatic dicarboxylic acid. It is done. In addition, the “monomer unit derived from” a specific monomer is, in other words, “structural unit formed by polymerization” of the monomer. Therefore, each monomer unit has a structure that directly includes the structure in the monomer that did not contribute to the polymerization.

  The following can be illustrated as a suitable monomer which comprises these monomer units. That is, first, examples of the aromatic hydroxycarboxylic acid include parahydroxybenzoic acid, metahydroxybenzoic acid, 2-hydroxy-6-naphthoic acid, 2-hydroxy-3-naphthoic acid, and 1-hydroxy-4-naphthoic acid. 4-hydroxy-4'-carboxydiphenyl ether, 2,6-dichloro-parahydroxybenzoic acid, 2-chloro-parahydroxybenzoic acid, 2,6-difluoro-parahydroxybenzoic acid, 4-hydroxy-4'-biphenyl A carboxylic acid etc. are mentioned. As the aromatic hydroxycarboxylic acid, only one kind of these may be applied, or a plurality of kinds may be combined.

  Among these, parahydroxybenzoic acid or 2-hydroxy-6-naphthoic acid is preferable because the deflection temperature under load of the first liquid crystalline polymer is easily within the above range and is easily available.

  Examples of the aromatic diol include hydroquinone, resorcin, methylhydroquinone, chlorohydroquinone, acetoxyhydroquinone, nitrohydroquinone, 4,4′-dihydroxybiphenyl, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1,6- Dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2 , 2-bis (4-hydroxy-3,5-dichlorophenyl) propane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 2,2-bis (4-hydroxy-3-chlorophenyl) propane, Bis- (4-hydroxy Phenyl) methane, bis- (4-hydroxy-3,5-dimethylphenyl) methane, bis- (4-hydroxy-3,5-dichlorophenyl) methane, bis- (4-hydroxy-3,5-dibromophenyl) methane Bis- (4-hydroxy-3-methylphenyl) methane, bis- (4-hydroxy-3-chlorophenyl) methane, 1,1-bis (4-hydroxyphenyl) cyclohexane, bis- (4-hydroxyphenyl) ketone Bis- (4-hydroxy-3,5-dimethylphenyl) ketone, bis- (4-hydroxy-3,5-dichlorophenyl) ketone, bis- (4-hydroxyphenyl) sulfide, bis- (4-hydroxyphenyl) And sulfone. These may be used alone or in combination of two or more.

  Among these, 4,4′-dihydroxybiphenyl, hydroquinone, resorcin, or 2,6-dihydroxynaphthalene is preferable because it is excellent in the effect of improving the heat resistance of the first liquid crystalline polymer and is easily available. .

  Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, methylterephthalic acid, methylisophthalic acid, diphenylether- Examples include 4,4′-dicarboxylic acid, diphenylsulfone-4,4′-dicarboxylic acid, diphenylketone-4,4′-dicarboxylic acid, 2,2′-diphenylpropane-4,4′-dicarboxylic acid. These may be used alone or in combination of two or more.

  Among these, terephthalic acid, isophthalic acid or 2,6-naphthalenedicarboxylic acid is preferable because it is excellent in the effect of improving the heat resistance of the first liquid crystalline polymer and is easily available.

  Moreover, as a 1st liquid crystalline polymer, 30-80 mol% of monomer units derived from aromatic hydroxycarboxylic acid, 10-35 mol% of monomer units derived from aromatic diol, and a monomer unit derived from aromatic dicarboxylic acid Is preferably 10 to 35 mol%. The first liquid crystalline polymer having such a structure tends to have a deflection temperature under load and the like within the above-described range. Such a 1st liquid crystalline polymer can be obtained by mix | blending and polymerizing each monomer in said ratio.

  The first liquid crystalline polymer has a configuration including the above-described monomer unit. The first liquid crystalline polymer has a bent monomer structure content, and the following second liquid crystalline polymer. Is preferably smaller. In particular, the content of the monomer unit having the bent structure is preferably less than 10 mol%. As a result, the deflection temperature under load of the first liquid crystalline polymer tends to be in the preferred range described above. Examples of the monomer unit having a bent structure include a monomer unit having a 1,3-phenylene skeleton, a monomer unit having a 2,3-phenylene skeleton, and a monomer unit having a 2,3-naphthalene skeleton. .

  The second liquid crystalline polymer is a thermotropic liquid crystalline polymer that exhibits liquid crystallinity when melted, and has a deflection temperature under load of less than 200 ° C. and is lower than the first liquid crystalline polymer. This second liquid crystalline polymer is preferably a polymer having a deflection temperature under load of 190 ° C. or lower, more preferably 150 ° C. or lower. Moreover, as a 2nd liquid crystalline polymer, what has an ester bond which couple | bonds the structural units is preferable. Furthermore, the second liquid crystalline polymer is more preferably a polymer having no amide bond.

  The second liquid crystalline polymer has a melting point of 270 ° C. or higher and lower than 400 ° C. As described above, the melting point is a value observed by DSC measurement at a heating rate of 10 to 25 ° C./min. The melting point of the second liquid crystalline polymer is preferably 295 ° C. or higher, and more preferably 310 ° C. or higher. When the melting point of the second liquid crystalline polymer is less than 270 ° C., foaming or swelling of the molded product is likely to occur when the molded product is subjected to solder reflow or the like. On the other hand, when the temperature is 400 ° C. or higher, an excessively high temperature is required for molding, and the liquid crystalline polymer composition is easily deteriorated during molding.

  The second liquid crystalline polymer is preferably a polymer having a glass transition temperature. The glass transition temperature of the second liquid crystalline polymer is preferably 50 to 200 ° C, more preferably 70 to 180 ° C, and still more preferably 100 to 180 ° C. When the second polymer has the glass transition temperature in this manner, the deflection temperature under load of the second liquid crystalline polymer can be easily adjusted to the above preferable range, and the residual stress of the obtained molded product can be reduced. As a result, the warpage of the molded product can be more effectively reduced. The glass transition temperature can be measured by the DSC measurement described above.

  Furthermore, the second liquid crystalline polymer has a flow start temperature of 270 ° C. or higher. When the flow start temperature of the second liquid crystalline polymer is less than 270 ° C., when a treatment such as solder reflow is performed using a molded product obtained by molding the liquid crystalline polymer composition, foaming or There is a tendency that swelling is likely to occur. From the viewpoint of further reducing such inconvenience, the flow start temperature of the second liquid crystalline polymer is more preferably 277 ° C. or higher. However, the flow start temperature of the second liquid crystalline polymer is preferably less than 400 ° C. from the viewpoint of preventing deterioration of the liquid crystalline polymer composition during molding.

  Such a second liquid crystalline polymer is not particularly limited as long as it satisfies the above-mentioned characteristics, and examples thereof include wholly aromatic polyesters and aromatic-aliphatic polyesters. From the viewpoint of reducing foaming and swelling after solder reflow of the molded product, wholly aromatic polyester is preferable. As the preferred wholly aromatic polyester, as in the first liquid crystalline polymer described above, a monomer unit derived from an aromatic hydroxycarboxylic acid, a monomer unit derived from an aromatic diol, and a monomer unit derived from an aromatic dicarboxylic acid Those having the following are preferred.

  The second liquid crystalline polymer preferably has a monomer unit having a bent structure in its structure. Examples of the monomer unit having such a bent structure include a monomer unit having a 1,3-phenylene skeleton, a monomer unit having a 2,3-phenylene skeleton, and a monomer unit having a 2,3-naphthalene skeleton.

  When the second liquid crystalline polymer contains a monomer unit having such a bent structure, the second liquid crystalline polymer is likely to have a suitable deflection temperature under load, and compared with the first liquid crystalline polymer. As a result, the liquid crystallinity is appropriately reduced. As a result, the liquid crystalline polymer composition is less likely to be warped during molding and during high-temperature treatment after molding. From the viewpoint of more reliably obtaining such an effect, the second liquid crystalline polymer preferably has 10 to 45 mol% of monomer units having these bent structures, and more preferably 12.5 to 40 mol%. preferable.

  More specifically, examples of the monomer unit having the above bent structure include monomer units derived from isophthalic acid, phthalic acid, 2,3-naphthalenedicarboxylic acid, resorcin, or derivatives thereof, and 3,3′-biphenyl. Examples thereof include monomer units derived from dicarboxylic acid, 4,3′-biphenyldicarboxylic acid or derivatives thereof. Among them, the monomer unit derived from isophthalic acid or resorcin tends to make the second liquid crystalline polymer have good characteristics.

  The first and second liquid crystalline polymers are those described above, but in the liquid crystalline polymer composition of the present embodiment, the first liquid crystalline polymer contains all the monomer units of the second liquid crystalline polymer. It is preferable that As a result, the compatibility between the first liquid crystalline polymer and the second liquid crystalline polymer is improved during molding, and the liquid crystallinity (anisotropy) of the liquid crystalline polymer composition is more effectively reduced. To get.

  As a suitable combination of the first and second liquid crystalline polymers, first, the first liquid crystalline polymer includes all the monomer units of the second liquid crystalline polymer, and further includes other monomer units. This is the case. In this case, as the other monomer unit of the first liquid crystalline polymer, a monomer unit having no bent structure is preferable. Examples of such a monomer unit include a monomer unit derived from terephthalic acid and a monomer unit derived from 2,6-naphthalenedicarboxylic acid.

  Further, even if the first and second liquid crystalline polymers are composed of the same monomer unit, it is preferable if the blending ratio of the monomer units is different so as to cause the difference in deflection temperature under load as described above. Can be a combination.

  As a suitable combination of the first and second liquid crystalline polymers, the first and second liquid crystalline polymers are respectively (1) monomer units derived from aromatic hydroxycarboxylic acid (hereinafter referred to as “hydroxycarboxylic acid units”). ), (2) a monomer unit derived from an aromatic diol (hereinafter abbreviated as “diol unit”), and (3) a monomer unit derived from an aromatic dicarboxylic acid (hereinafter referred to as “dicarboxylic acid unit”). (Abbreviated) are included, and examples of such combinations include the following (A) or (B).

  First, as (A), the first liquid crystal polymer has (1) one or more monomer units of parahydroxybenzoic acid and 2-hydroxy-6-naphthoic acid as hydroxycarboxylic acid units, (2) As a diol unit, it has at least one monomer unit of 4,4′-dihydroxybiphenyl, hydroquinone, resorcin, and 2,6-dihydroxynaphthalene, and (3) consists of isophthalic acid as a dicarboxylic acid unit. It is a polymer having at least a monomer unit, and optionally having at least one monomer unit of terephthalic acid and 2,6-naphthalenedicarboxylic acid, and the second liquid crystal polymer is (3) dicarboxylic acid The same monomer as the first liquid crystal polymer except that it contains only a monomer unit consisting of isophthalic acid as a unit. The combination is a polymer composed of units and the like.

  In addition, as (B), the first liquid crystal polymer has (1) one or more monomer units of parahydroxybenzoic acid and 2-hydroxy-6-naphthoic acid as hydroxycarboxylic acid units, 2) As a diol unit, it has at least a monomer unit composed of resorcin, and optionally has one or more monomer units of 4,4′-dihydroxybiphenyl, hydroquinone and 2,6-dihydroxynaphthalene. , (3) a polymer having at least one monomer unit of terephthalic acid, isophthalic acid and 2,6-naphthalenedicarboxylic acid as a dicarboxylic acid unit, and (2) resorcinol as a diol unit From the same monomer unit as the first liquid crystal polymer, except that only the monomer unit consisting of Mentioned combination is a polymer made is.

  More specifically, among the combinations of (A), (1) a combination having only a monomer unit composed of (C) parahydroxybenzoic acid is preferred as the hydroxycarboxylic acid unit. Among such combinations, in particular, (2) as a diol unit, (D) one having only a monomer unit consisting of 4,4′-dihydroxybiphenyl, (E) one having only a monomer unit consisting of hydroquinone, or ( F) Those having a monomer unit composed of 4,4′-dihydroxybiphenyl and a monomer unit composed of hydroquinone are preferred.

  Further, as the combination (A), a combination having only a monomer unit (G) 2-hydroxy-6-naphthoic acid as a monomer unit composed of an aromatic hydroxycarboxylic acid is also suitable. Among these combinations, (2) as diol units, (H) those having only monomer units consisting of 4,4′-dihydroxybiphenyl, (I) those having only monomer units consisting of hydroquinone, or (J) Those having a monomer unit composed of 4,4′-dihydroxybiphenyl and a monomer unit composed of hydroquinone are preferred.

  In the liquid crystalline polymer composition of the present embodiment, the first liquid crystalline polymer and the second liquid crystalline polymer are included in the total mass of 30 to 95% by mass and 5 to 70% by mass, respectively. In other words, in the total mass of the first liquid crystalline polymer and the second liquid crystalline polymer, the content of the second liquid crystalline polymer is 5 to 70% by mass. The content of the second liquid crystalline polymer is preferably 15 to 60% by mass, and more preferably 30 to 45% by mass. When the content of the second liquid crystalline polymer is 70% by mass or more, the heat resistance of the liquid crystalline polymer composition is lowered, and deformation of the molded product is remarkably caused in reflow or the like. On the other hand, if it is less than 5% by mass, the occurrence of warpage of the molded product cannot be sufficiently reduced.

  In the liquid crystalline polymer composition, the first liquid crystalline polymer and the second liquid crystalline polymer are each preferably in the form of a powder having an average particle size of 1 mm or less, and each has an average particle size of 0.1 to 1 mm. It is more preferable that it is in the form of a powder. In this case, the shape of the particles constituting the powder is not particularly limited. Thereby, in the liquid crystalline polymer composition, the first and second liquid crystalline polymers are likely to be uniformly dispersed. As a result, the effect of reducing anisotropy due to the mixing of both is obtained satisfactorily, and the warpage of the molded product can be further reduced. In particular, the second liquid crystalline polymer is preferably obtained by solid phase polymerization of a powdery prepolymer having an average particle size of 1 mm or less. According to such a second liquid crystalline polymer, the anisotropy of the liquid crystalline polymer composition can be further reduced.

  The liquid crystalline polymer composition according to a preferred embodiment preferably further includes an organic or inorganic filler in addition to the first and second liquid crystalline polymers. By including an organic or inorganic filler, warpage of the molded product can be further reduced. As the organic or inorganic filler, fibrous, granular or plate-like ones can be applied without particular limitation.

  Examples of inorganic fillers include fiber fillers such as glass fiber, silica fiber, silica / alumina fiber, alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate fiber, wollast. Examples thereof include silicate fibers such as knight, magnesium sulfate fibers, aluminum borate fibers, and other metal fibrous materials such as stainless steel, aluminum, titanium, copper, and brass. Of these, glass fiber is preferred.

  As granular fillers, carbon black, graphite, silica, quartz powder, glass beads, milled glass fiber, glass balloon, glass powder, calcium oxalate, aluminum oxalate, kaolin, clay, diatomaceous earth, wollast Silicates such as knight, metal oxides such as iron oxide, titanium oxide, zinc oxide, antimony trioxide and alumina, metal carbonates such as calcium carbonate and magnesium carbonate, metal sulfates such as calcium sulfate and barium sulfate, etc. , Ferrite, silicon carbide, silicon nitride, boron nitride, metal powder, and the like. Furthermore, examples of the plate-like filler include mica, glass flakes, talc and various metal foils.

  Organic fillers include high-melting organic fibrous materials such as polyamide, fluororesin, polyester resin, acrylic resin, and heat-resistant materials such as aromatic polyester fiber, liquid crystalline polymer fiber, aromatic polyamide fiber, and polyimide fiber. And synthetic fibers having high strength and high strength.

  These organic or inorganic fillers can be used alone or in combination of two or more. In particular, when an organic filler and an inorganic filler are used in combination, the mechanical strength, dimensional accuracy, electrical properties and the like of a molded product obtained from the liquid crystalline polymer composition tend to be improved.

  The compounding amount of the organic or inorganic filler is preferably 1 to 80% by mass, more preferably 5 to 65% by mass, and further preferably 20 to 55% by mass in the total mass of the liquid crystalline polymer composition. preferable. In addition, when an organic filler and an inorganic filler are included in combination, the total of these is preferably the above blending amount. If the blending amount of the organic or inorganic filler is less than 1% by mass, the effect of reducing warpage of the molded product may not be sufficiently obtained. On the other hand, if it exceeds 80% by mass, the mechanical strength of the molded product may be undesirably lowered.

  The liquid crystalline polymer composition of the present embodiment containing each of the above components preferably has a deflection temperature under load of 220 ° C. or higher, more preferably 230 ° C. or higher, and further preferably 250 ° C. or higher. By having a load deflection temperature of 220 ° C. or higher in the entire liquid crystalline polymer composition, the heat resistance of the molded product is improved, and the occurrence of warpage of the molded product can be reduced extremely well.

In addition, the liquid crystalline polymer composition may further contain other components other than the first and second liquid crystalline polymers and the organic or inorganic filler as long as the above-described characteristics and the like are not impaired. Examples of other components include resins other than those described above, coupling agents, ultraviolet absorbers, and heat stabilizers.
[Method for Producing Liquid Crystalline Polymer Composition]

  Next, the example of the suitable manufacturing method of the liquid crystalline polymer composition mentioned above is demonstrated.

  In a preferred embodiment of the method for producing a liquid crystalline polymer composition, the powdery first prepolymer having an average particle diameter of 1 mm or less is solid-phase polymerized, and the deflection temperature under load is 200 ° C. or higher. A step of obtaining a liquid crystalline polymer by solid-phase polymerization of a powdery second prepolymer having an average particle size of 1 mm or less, and a deflection temperature under load is less than 200 ° C. and lower than the first liquid crystalline polymer; A step of obtaining a second liquid crystalline polymer having a melting point of 270 ° C. or higher and lower than 400 ° C. and having a flow start temperature of 270 ° C. or higher, and the first liquid crystalline polymer and the second liquid crystalline polymer, Mixing. With such a production method, the liquid crystalline polymer composition as described above can be produced satisfactorily.

  More specifically, for example, the following methods can be mentioned. That is, first, each raw material monomer of the first or second liquid crystalline polymer is reacted to obtain the first or second prepolymer, respectively. For example, when the first or second liquid crystalline polymer is the above-described wholly aromatic polyester, the first or second prepolymer is acylated after the hydroxyl group of the raw material monomer is acylated with an acid anhydride. And a method of transesterifying the carboxyl group of the raw material monomer. As such a synthesis method, methods disclosed in JP-A No. 2002-220444 and JP-A No. 2002-146003 can be applied. The prepolymer thus obtained preferably has a molecular weight of 2000 to 60000.

  Next, after the obtained first or second prepolymer is cooled to about room temperature to form solids, the obtained solids are pulverized to form powders, flakes, and the like. Process. The average particle size of the first or second prepolymer powder is preferably 1 mm or less, more preferably 0.1 to 1 mm.

  Thereafter, the first or second prepolymer is further polymerized (high molecular weight) by causing solid-phase polymerization, for example, by heating in a powder form. Thereby, the powdery first or second liquid crystalline polymer having an average particle diameter of 1 mm or less, preferably 0.1 mm to 1 mm is obtained. Such solid phase polymerization is performed until the first or second liquid crystalline polymer satisfies the above-described conditions (deflection temperature under load).

Then, the obtained first liquid crystalline polymer, second liquid crystalline polymer and, if necessary, organic or inorganic filler (hereinafter collectively referred to as “filler”) and other components are mixed, A liquid crystalline polymer composition is obtained. As a method for preparing the liquid crystalline polymer composition, for example, (1) a method in which a filler is blended in each of the first liquid crystalline polymer and the second liquid crystalline polymer, and these are mixed with an extruder or a kneader ( 2) A method of forming a pellet by adding a filler to each of the first liquid crystalline polymer and the second liquid crystalline polymer, and combining them at the time of molding, (3) the first liquid crystalline polymer and the second liquid crystalline The method of mixing a polymer, adding a filler further, and mixing with an extruder or a kneader, etc. are mentioned.
[Molding]

  The liquid crystalline polymer composition of the above-described embodiment can be processed into a molded product having a desired shape by molding. Since the liquid crystalline polymer composition contains the first and second liquid crystalline polymers, the liquid crystalline polymer composition has excellent fluidity at the time of melting and can be molded at a relatively low temperature. As a molding method of the liquid crystalline polymer composition, various molding methods such as injection molding, extrusion molding and compression molding can be applied, and processing into various shapes such as a three-dimensional shape, a fiber shape, and a film shape is easy.

  As described above, the liquid crystalline polymer composition not only can reduce warpage during molding, but can also reduce warpage during high-temperature treatment after molding such as reflow. Therefore, the molded article of the liquid crystalline polymer composition is suitable as an electronic component for surface mounting such as a printed wiring board, a semiconductor, a resistor, a capacitor, a coil, a switch, a relay, and a connector. Among them, it is suitable as a planar connector such as a board-to-board connector for a flexible printed board, a fine pitch multi-terminal connector, a card connector, a memory socket, and a CPU socket. A planar connector is a component for connecting a package such as LSI or memory that is joined by surface mounting to a printed wiring board, or a component for connecting a wiring for communication with another board to the printed wiring board. It is.

  FIG. 1 is a perspective view showing a planar connector which is an example of a molded product. The planar connector 1 is composed of a main body portion 2 and a rib portion 4 provided with a large number of ribs 6 on the surface, each of which is formed by molding the liquid crystalline polymer composition described above. The main body 2 is relatively thick and has a function of maintaining the strength of the planar connector 1. The rib portion 4 has a structure that is thinner than the main body portion 2. For example, the planar connector 1 is placed on a printed wiring board, and a metal terminal such as a mounting component is inserted into the rib 6 in the rib portion 6 to connect the printed wiring board and the mounting component. It can be carried out. In the planar connector 1, the width and thickness of the main body 2 and the rib 4, the ratio between the main body 2 and the rib 4, and their shapes are determined according to the required strength and the number of pins. .

  Although the planar connector 1 is made of the molded product of the liquid crystalline polymer composition of the present embodiment described above in spite of having such a thin rib portion 4, when the solder reflow or the like is performed. Even if it exists, the occurrence of warping is small. Therefore, the planar connector 1 is excellent in shape and dimensional stability when performing solder reflow or the like, and can be suitably applied as a connector.

EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to these Examples.
[Polymer characterization]

  In the synthesis of the following first or second liquid crystalline polymer, the flow start temperature, glass transition temperature, melting point and deflection temperature under load of the polymer to be measured were measured according to the following methods.

(Flow start temperature)
The flow start temperature was measured using a flow tester (manufactured by Shimadzu Corporation, CFT-500 type). Specifically, first, about 2 g of a sample was filled in a capillary rheometer equipped with a die having an inner diameter of 1 mm and a length of 10 mm. Then, while applying a load of 9.8 MPa (100 kg / cm ² ) and extruding the liquid crystalline polymer from the nozzle at a heating rate of 4 ° C./min, a temperature at which the melt viscosity is 4800 Pa · s (48000 poise) is measured, This temperature was defined as the flow start temperature.

(Measurement of glass transition temperature and melting point)
Using the analytical differential scanning calorimetry system “DSC6200” manufactured by Seiko Instruments Inc., the calorimetric profile obtained at a heating rate of 10 ° C./min is measured for the polymer to be measured, and the endothermic peak in the obtained endothermic curve is measured. The lowest temperature was taken as the melting point. Moreover, the temperature which becomes an inflection point in the endothermic curve appearing on the lower temperature side than the melting point was defined as the glass transition temperature.

(Load deflection temperature)
First, the polymer to be measured was granulated to obtain pellets. After drying this at 120 ° C. for 3 hours, using an injection molding machine (PS40E5ASE type manufactured by Nissin Plastic Industry Co., Ltd.), the cylinder temperature is set to 350 ° C., and molding is performed at a predetermined mold temperature. A test piece having a width of 127 mm, a width of 12.7 mm, and a thickness of 6.4 mm was formed. Using this, it was measured at a load of 18.6 kg / cm ² by a method based on ASTM D648. For the liquid crystalline polymers of Synthesis Examples 1 and 2 below, the mold temperature during molding was 130 ° C., and for the liquid crystalline polymers of Synthesis Examples 3 to 6 below, the mold temperature during molding was 70 ° C. .
[Synthesis of liquid crystalline polymer]

(Synthesis Example 1)
In a reactor equipped with a stirrer, a torque meter, a nitrogen gas inlet tube, a thermometer and a reflux condenser, 911 g (6.6 mol) of p-hydroxybenzoic acid and 409 g of 2,4′-dihydroxybiphenyl (2. 2 mol), 91 g (0.55 mol) of isophthalic acid, 274 g (1.65 mol) of terephthalic acid and 1235 g (12.1 mol) of acetic anhydride were added and stirred. Next, 0.17 g of 1-methylimidazole was added to the mixture after stirring, and the inside of the reactor was sufficiently replaced with nitrogen gas, and then heated to 150 ° C. over 15 minutes under a nitrogen gas stream, The temperature was maintained and refluxed for 1 hour. Thereafter, 1.7 g of 1-methylimidazole was further added, and then the temperature was raised to 320 ° C. over 2 hours and 50 minutes while distilling off by-product acetic acid and unreacted acetic anhydride. The time at which an increase in torque was observed was regarded as the end of the reaction, and the contents were taken out.

  Next, the taken-out contents were cooled to room temperature and then pulverized by a pulverizer to obtain a prepolymer powder having a particle size of about 0.1 mm to about 1 mm. A part of the obtained prepolymer powder was taken out and its flow initiation temperature was measured.

  Then, the prepolymer powder was heated from 25 ° C. to 250 ° C. over 1 hour, then heated from this temperature to 285 ° C. over 5 hours, and further kept at that temperature for 3 hours for solid phase polymerization. It was. The powder after the solid phase polymerization was cooled to obtain a liquid crystalline polymer powder. It was 327 degreeC when the flow start temperature of the obtained liquid crystalline polymer was measured similarly to the above. Further, when DSC measurement was performed on the liquid crystalline polymer powder, the melting point was 340 ° C., and the glass transition temperature was not observed.

  Furthermore, a part of the liquid crystalline polymer was formed into pellets by granulation, and processed into a test piece for measuring a deflection temperature under load by injection molding. It was 241 degreeC when the deflection temperature under load was measured using the obtained test piece.

(Synthesis Example 2)
In a reactor equipped with a stirrer, a torque meter, a nitrogen gas inlet tube, a thermometer, and a reflux condenser, 995 g (7.2 mol) of p-hydroxybenzoic acid and 447 g of 2,4′-dihydroxybiphenyl (2. 4 mol), 159 g (0.96 mol) of isophthalic acid, 239 g (1.44 mol) of terephthalic acid, and 1348 g (13.2 mol) of acetic anhydride were added and stirred. Next, 0.18 g of 1-methylimidazole was added to the mixture after stirring, and the inside of the reactor was sufficiently replaced with nitrogen gas, and then heated to 150 ° C. over 15 minutes under a nitrogen gas stream, The temperature was maintained and refluxed for 1 hour. Thereafter, 1.8 g of 1-methylimidazole was further added, and then the temperature was raised to 320 ° C. over 2 hours and 50 minutes while distilling off by-product acetic acid and unreacted acetic anhydride. The time at which an increase in torque was observed was regarded as the end of the reaction, and the contents were taken out.

  Next, in the same manner as in Synthesis Example 1, a prepolymer powder having a particle size of about 0.1 mm to about 1 mm was obtained. A part of the obtained prepolymer powder was taken out and its flow initiation temperature was measured.

  Then, the prepolymer powder was heated from 25 ° C. to 200 ° C. over 1 hour, then heated from this temperature to 242 ° C. over 5 hours, and further kept at that temperature for 3 hours for solid phase polymerization. It was. The powder after the solid phase polymerization was cooled to obtain a liquid crystalline polymer powder. It was 288 degreeC when the flow start temperature of the obtained liquid crystalline polymer was measured like the above. Further, when DSC measurement was performed on the liquid crystalline polymer powder, the melting point was 310 ° C., and the glass transition temperature was not observed.

  Furthermore, a part of the liquid crystalline polymer was formed into pellets by granulation, and processed into a test piece for measuring a deflection temperature under load by injection molding. It was 220 degreeC when the deflection temperature under load was measured using the obtained test piece.

(Synthesis Example 3)
In a reactor equipped with a stirrer, a torque meter, a nitrogen gas inlet tube, a thermometer and a reflux condenser, 828 g (6.0 mol) of p-hydroxybenzoic acid and 559 g (3. 0 mol), 498 g (3.0 mol) of isophthalic acid and 1348 g (13.2 mol) of acetic anhydride were added, and these were stirred. Next, 0.19 g of 1-methylimidazole was added to the mixture after stirring, and the inside of the reactor was sufficiently replaced with nitrogen gas, and then the temperature was raised to 150 ° C. over 15 minutes under a nitrogen gas stream. The temperature was maintained and refluxed for 1 hour. Thereafter, the temperature was raised to 320 ° C. over 2 hours and 50 minutes while distilling off distilling by-product acetic acid and unreacted acetic anhydride. The time at which an increase in torque was observed was regarded as the end of the reaction, and the contents were taken out.

  Next, in the same manner as in Synthesis Example 1, a prepolymer powder having a particle size of about 0.1 mm to about 1 mm was obtained. A part of the obtained prepolymer powder was taken out and its flow initiation temperature was measured.

  Then, the prepolymer powder was heated from 25 ° C. to 200 ° C. over 1 hour, then heated from this temperature to 240 ° C. over 5 hours, and further kept at that temperature for 3 hours for solid phase polymerization. It was. The powder after the solid phase polymerization was cooled to obtain a liquid crystalline polymer powder. It was 283 degreeC when the flow start temperature of the obtained liquid crystalline polymer was measured similarly to the above. Further, when DSC measurement was performed on the liquid crystalline polymer powder, the glass transition temperature was 129 ° C. and the melting point was 326 ° C.

  Furthermore, a part of the liquid crystalline polymer was formed into pellets by granulation, and processed into a test piece for measuring a deflection temperature under load by injection molding. It was 133 degreeC when the deflection temperature under load was measured using the obtained test piece.

(Synthesis Example 4)
In a reactor equipped with a stirrer, a torque meter, a nitrogen gas introduction tube, a thermometer and a reflux condenser, 1243 g (9.0 mol) of p-hydroxybenzoic acid and 279 g (1. 5 mol), 249 g (1.5 mol) of isophthalic acid and 1348 g (13.2 mol) of acetic anhydride were added, and these were stirred. Next, 0.19 g of 1-methylimidazole was added to the mixture after stirring, and the inside of the reactor was sufficiently replaced with nitrogen gas, and then the temperature was raised to 150 ° C. over 15 minutes under a nitrogen gas stream. The temperature was maintained and refluxed for 1 hour. Thereafter, the temperature was raised to 320 ° C. over 2 hours and 50 minutes while distilling off distilling by-product acetic acid and unreacted acetic anhydride. The time at which an increase in torque was observed was regarded as the end of the reaction, and the contents were taken out.

  Next, in the same manner as in Synthesis Example 1, a prepolymer powder having a particle size of about 0.1 mm to about 1 mm was obtained. A part of the obtained prepolymer powder was taken out and its flow initiation temperature was measured.

  Then, the prepolymer powder was heated from 25 ° C. to 200 ° C. over 1 hour, then heated from this temperature to 260 ° C. over 5 hours, and further kept at that temperature for 3 hours for solid phase polymerization. It was. The powder after the solid phase polymerization was cooled to obtain a liquid crystalline polymer powder. It was 307 degreeC when the flow start temperature of the obtained liquid crystalline polymer was measured similarly to the above. Moreover, when the DSC measurement was implemented about this liquid crystalline polymer powder, the glass transition temperature was 104 degreeC and melting | fusing point was 312 degreeC.

  Furthermore, a part of the liquid crystalline polymer was formed into pellets by granulation, and processed into a test piece for measuring a deflection temperature under load by injection molding. It was 138 degreeC when the deflection temperature under load was measured using the obtained test piece.

(Synthesis Example 5)
In a reactor equipped with a stirrer, a torque meter, a nitrogen gas inlet tube, a thermometer, and a reflux condenser, 941 g (5.0 mol) of p-hydroxy-6-naphthoic acid and 273 g of 4-aminophenol (2. 5 mol), 415.3 g (2.5 mol) of isophthalic acid and 1123 g (11 mol) of acetic anhydride were added, and these were stirred. After sufficiently replacing the inside of the reactor with nitrogen gas, the temperature was raised to 150 ° C. over 15 minutes under a nitrogen gas stream, and the temperature was maintained as it was and refluxed for 3 hours. Thereafter, the temperature was raised to 320 ° C. over 170 minutes while distilling off by-product acetic acid and unreacted acetic anhydride. The time at which an increase in torque was observed was regarded as the end of the reaction, and the contents were taken out.

  Next, in the same manner as in Synthesis Example 1, a prepolymer powder having a particle size of about 0.1 mm to about 1 mm was obtained. A part of the obtained prepolymer powder was taken out and its flow initiation temperature was measured, and it was 182 ° C.

  Then, the prepolymer powder was heated from 25 ° C. to 200 ° C. over 1 hour, then heated from this temperature to 260 ° C. over 5 hours, and further kept at the same temperature for 10 hours for solid phase polymerization. It was. The powder after the solid phase polymerization was cooled to obtain a liquid crystalline polymer powder. It was 323 degreeC when the flow start temperature of the obtained liquid crystalline polymer was measured similarly to the above. Further, when DSC measurement was performed on the liquid crystalline polymer powder, the glass transition temperature was 160 ° C., and no melting point was observed.

  Furthermore, a part of the liquid crystalline polymer was formed into pellets by granulation, and processed into a test piece for measuring a deflection temperature under load by injection molding. It was 152 degreeC when the deflection temperature under load was measured using the obtained test piece.

(Synthesis Example 6)
First, a prepolymer powder having a particle size of about 0.1 mm to about 1 mm was obtained in the same process as in Synthesis Example 3. Then, this prepolymer powder was heated from 25 ° C. to 200 ° C. over 1 hour, then heated from this temperature to 220 ° C. over 5 hours, and further kept at the same temperature for 3 hours. I let you. The powder after the solid phase polymerization was cooled to obtain a liquid crystalline polymer powder. It was 265 degreeC when the flow start temperature of the obtained liquid crystalline polymer was measured similarly to the above. Further, when the DSC measurement was performed on the liquid crystalline polymer powder, the glass transition temperature was 104 ° C. and the melting point was 312 ° C.

Furthermore, a part of the liquid crystalline polymer was formed into pellets by granulation, and processed into a test piece for measuring a deflection temperature under load by injection molding. It was 136 degreeC when the deflection temperature under load was measured using the obtained test piece.
[Preparation of liquid crystalline polymer composition]

(Examples 1-4, Comparative Examples 1-7)
The above-described liquid crystalline polymers of Synthesis Examples 1 to 5 and the chopped glass fiber (CS03JAPX-1 manufactured by Asahi Fiber Glass Co., Ltd.) as a filler are mixed at a mixing ratio (weight ratio) shown in Table 1, and a twin screw extruder A liquid crystalline polymer composition was obtained by granulating at a cylinder temperature of 340 ° C. using a PCM-30 model (Ikegai Iron Works Co., Ltd.) and further kneading. Further, the deflection temperature under load of the obtained liquid crystalline polymer composition was measured in the same manner as described above by using an injection molding machine (PS40E5ASE type manufactured by Nissin Plastic Industry Co., Ltd.). These values are also shown in Table 1.

［特性評価］

[Characteristic evaluation]

  Using the liquid crystalline polymer compositions of Examples 1 to 4 and Comparative Examples 1 to 7, respectively, warpage of molded products obtained from the liquid crystalline polymer compositions according to the method shown below, presence or absence of foaming by solder foam test, etc. Was evaluated. Moreover, the bending characteristic was evaluated about the molded article obtained from the liquid crystalline polymer of Example 1, Comparative Examples 1-3, and Comparative Examples 6-7.

(Evaluation of warpage of molded products)
Each liquid crystalline polymer composition was granulated, and the obtained pellets were dried at 120 ° C. for 3 hours, and then a cylinder temperature of 350 using an injection molding machine (manufactured by Nissei Plastic Industry Co., Ltd., UH1000) using a disk mold. A disk-shaped sample having a diameter of 64 mm and a thickness of 0.5 mm was obtained by molding at a temperature of 0 ° C. and a mold temperature of 130 ° C. Then, place the obtained sample on the surface plate, use the outer periphery of the disk as the reference surface and the farthest part from the surface plate as the gate portion, and measure the height from the reference surface to the gate portion with a micrometer. The displacement was determined. The obtained value was taken as the amount of warpage of the molded product.

  Next, the sample after measuring the warpage was placed in an oven having an internal temperature of 260 ° C. and heat-treated for 90 seconds. After the treatment, a sample was taken out and the amount of warpage was determined in the same manner as described above. The obtained value was taken as the amount of warpage after heat treatment.

  The warpage amount of the obtained molded product and the warpage amount after heat treatment are shown in Table 2, respectively. These measurements were carried out using five samples each using the liquid crystalline polymer of each Example or Comparative Example, and the average values thereof are shown in Table 2. In addition, in the table, “shape change” is shown for samples in which the shape change is so difficult that it is difficult to measure the amount of warpage after heat treatment.

(Solder foam test)
After granulating each liquid crystalline polymer composition and drying the obtained pellets at 120 ° C. for 3 hours, using an injection molding machine (manufactured by Nissei Plastic Industry Co., Ltd., PS40E5ASE type), the cylinder temperature is 350 ° C., A sample of JIS K71131 (1/1) dumbbell (thickness 1.2 mm) was molded at a mold temperature of 130 ° C. The obtained sample was immersed in H60A solder (60% tin, 40% lead) at 260 ° C. for 60 seconds. Thereafter, the sample was pulled up and checked for the occurrence of foaming and swelling. The obtained results are shown in Table 2.

(Bending characteristics)
After granulating each liquid crystalline polymer composition and drying the obtained pellets at 120 ° C. for 3 hours, the cylinder temperature was measured by an injection molding machine (manufactured by Nissei Plastic Industry Co., Ltd., PS40E5ASE type) using a disk mold. A test piece (sample) having a length of 127 mm, a width of 12.7 mm, and a thickness of 6.4 mm was formed by molding at 350 ° C. and a mold temperature of 130 ° C. And the bending strength and bending elastic modulus of these samples were measured by the method based on ASTMD790. The obtained results are shown in Table 3.

［液晶性ポリマー組成物の調製］

[Preparation of liquid crystalline polymer composition]

(Comparative Example 8)
Using the liquid crystalline polymer obtained in Synthesis Example 1 and the liquid crystalline polymer obtained in Synthesis Example 6 in the mixing ratio (weight ratio) shown in Table 4 below, the liquid crystalline polymer of Comparative Example 8 was used in the same manner as described above. A composition was prepared.
[Characteristic evaluation]

(Solder foam test)
Using the liquid crystalline polymer composition of Comparative Example 8, a solder foam test was conducted in the same manner as described above. Table 4 shows the obtained results.

  From Table 1 and 2, when the liquid crystalline polymer of Examples 1-4 was used, it was confirmed that both the curvature of a molded article and the curvature after heat processing are small. On the other hand, when the liquid crystalline polymer of Comparative Examples 1-7 was used, it turned out that the curvature after a molded article and heat processing is larger than an Example, and especially the curvature after heat processing is remarkable large. Further, from Table 3, the molded product using the liquid crystalline polymer of the example has bending properties comparable to those of the comparative example, and has mechanical properties sufficient for practical use. It was confirmed. Furthermore, from Table 4, it was found that when a second liquid crystalline polymer having a low flow start temperature is combined, foaming and swelling are likely to occur during high-temperature treatment after molding.

It is a perspective view which shows a planar connector.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Planar connector, 2 ... Main-body part, 4 ... Rib part, 6 ... Rib.

Claims (14)

A first liquid crystalline polymer having a deflection temperature under load of 200 ° C. or higher, and a second liquid crystalline polymer having a deflection temperature under load of less than 200 ° C .;
The first liquid crystalline polymer and the second liquid crystalline polymer are included in the total mass of 30 to 95% by mass and 5 to 70% by mass, respectively.
The second liquid crystalline polymer has a melting point of 270 ° C. or higher and lower than 400 ° C., and a flow start temperature is 270 ° C. or higher.
The liquid crystalline polymer composition characterized by the above-mentioned.   The first liquid crystalline polymer has a monomer unit derived from an aromatic hydroxycarboxylic acid, a monomer unit derived from an aromatic diol, and a monomer unit derived from an aromatic dicarboxylic acid. Liquid crystalline polymer composition.   3. The liquid crystalline polymer composition according to claim 1, wherein the second liquid crystalline polymer contains an ester bond that bonds the structural units constituting the polymer. 4.   The liquid crystalline polymer composition according to any one of claims 1 to 3, wherein the second liquid crystalline polymer has a melting point of 295 ° C or higher and lower than 400 ° C.   The second liquid crystalline polymer is at least one selected from the group consisting of a monomer unit having a 1,3-phenylene skeleton, a monomer unit having a 2,3-phenylene skeleton, and a monomer unit having a 2,3-naphthalene skeleton. The liquid crystalline polymer composition according to claim 1, comprising 10 to 45 mol% of monomer units.   The liquid crystal polymer composition according to any one of claims 1 to 5, wherein the first liquid crystal polymer includes all monomer units of the second liquid crystal polymer.   The liquid crystal according to any one of claims 1 to 6, wherein the first liquid crystalline polymer and the second liquid crystalline polymer are each in a powder form having an average particle diameter of 1 mm or less. Polymer composition.   The said 2nd liquid crystalline polymer is obtained by solid-phase-polymerizing the powdery prepolymer which has an average particle diameter of 1 mm or less, The any one of Claims 1-7 characterized by the above-mentioned. The liquid crystalline polymer composition described in 1.   The liquid crystalline polymer composition according to any one of claims 1 to 8, further comprising an organic filler or an inorganic filler.   The liquid crystalline polymer composition according to any one of claims 1 to 9, wherein a deflection temperature under load of the entire composition is 220 ° C or higher.   The molded article which can be obtained by shape | molding the liquid crystalline polymer composition as described in any one of Claims 1-10.   The planar connector which can be obtained by shape | molding the liquid crystalline polymer composition as described in any one of Claims 1-10. Solid phase polymerization of a powdery first prepolymer having an average particle diameter of 1 mm or less to obtain a first liquid crystalline polymer having a deflection temperature under load of 200 ° C. or higher;
A powdery second prepolymer having an average particle size of 1 mm or less is solid-phase polymerized, the deflection temperature under load is less than 200 ° C., the melting point is 270 ° C. or more and less than 400 ° C., and the flow start temperature. Obtaining a second liquid crystalline polymer having a temperature of 270 ° C. or higher;
Mixing the first liquid crystalline polymer and the second liquid crystalline polymer;
A method for producing a liquid crystalline polymer composition, comprising: The method for producing a liquid crystalline polymer composition according to claim 13, wherein the melting point of the second liquid crystalline polymer is 295 ° C or higher and lower than 400 ° C.

Images