JP2008280478A - Electronic component for surface mount - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic component for surface mount and a liquid crystal polymer composition for an electronic component for surface mount which have a reduced problem of flux creeping on surface mounting. <P>SOLUTION: A liquid crystal polymer composition contains 5 to 100 pts.wt. of a glass fiber having a number-average fiber diameter of 4 to 8 μm and a number-average fiber length of 100 to 200 μm to 100 pts.wt. of a wholly aromatic liquid crystal polymer having a crystal melting point of 310 to 410°C, and has a load deflection temperature of 280 to 360°C. The electronic component for surface mount is obtained by molding the liquid crystal polymer composition. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electronic component for surface mounting in which the problem of flux increase during surface mounting is reduced.

  Thermotropic liquid crystal polymers (hereinafter abbreviated as liquid crystal polymers or LCPs) are excellent in mechanical properties such as heat resistance and rigidity, chemical resistance, dimensional accuracy, etc. Its use is expanding to applications.

  Especially in the information / communication field such as personal computers and mobile phones, there is a rapid increase in the degree of integration, miniaturization, thinning, and low profile of parts, resulting in the formation of very thin parts. There are many. Therefore, LCP has been adopted as a material for many electronic components by taking advantage of its excellent moldability, that is, good fluidity and no characteristics of other resins such as no burrs.

  In recent years, in the assembly of electronic component materials into electronic devices, for the purpose of saving labor by automation, cream solder is printed on a substrate such as a printed circuit board, and switches, relays, connectors, capacitors, coils, transformers, semiconductors, In addition, surface mounting technology for performing soldering by heating with a reflow apparatus after fixing electronic components such as resistors has been developed, and its adoption is rapidly increasing.

  A surface mount electronic component using a liquid crystal polymer as a material has been proposed (see Patent Document 1). However, an electronic component using a liquid crystal polymer as a molding material is easily warped and deformed by heating during reflow treatment. The flux contained in the cream solder enters a slight gap between the liquid crystal polymer portion and the metal component portion caused by warping deformation, and the problem called “flux rise” that contaminates the metal component easily occurs.

  In addition, lead-free solder has been promoted in surface mount technology in accordance with the RoHS Directive, which strictly enforced the content of specific harmful substances such as lead in electrical and electronic equipment, which was enforced in Europe on July 1, 2006. .

  However, Sn-Ag-Cu-based, Sn-Ag-based, Sn-Cu-based and other alloys that are widely used as lead-free solder are Sn-Pb-based lead-containing solders (melting point: about 180 ° C.). Compared to the above, the melting point is as high as about 200 to 250 ° C., and in the surface mounting method using lead-free solder, the reflow processing temperature is also increased.

  For this reason, when an electronic component using a liquid crystal polymer as a molding material is surface-mounted using lead-free solder, the problem of increased flux becomes more prominent.

  As a method for solving the problem of flux increase, it is conceivable to suppress the occurrence of warpage of the liquid crystal polymer molded product. As a method for suppressing the occurrence of warpage of the liquid crystal polymer molded product, for example, a fiber filler such as glass fiber or aluminum borate whisker having a number average fiber length of 100 μm or less and a plate filler such as talc are mixed with the liquid crystal polymer. However, the method described in Patent Document 2 does not sufficiently solve the problem of flux increase.

  As described above, there is a strong demand for a solution to the problem of flux increase in electronic parts using liquid crystal polymers as molding materials.

Japanese Patent Laid-Open No. 08-143654 JP 2002-294038 A

  An object of the present invention is to provide an electronic component for surface mounting in which the problem of flux increase during surface mounting is reduced. A further object of the present invention is to provide a liquid crystal polymer composition for molding electronic components for surface mounting, which provides electronic components for surface mounting with reduced flux increase problems.

  The present invention relates to a glass fiber 5 having a number average fiber diameter of 4 to 8 μm and a number average fiber length of 100 to 200 μm with respect to 100 parts by weight of a wholly aromatic liquid crystal polymer having a crystal melting temperature of 310 to 410 ° C. The present invention relates to an electronic component for surface mounting obtained by molding a liquid crystal polymer composition comprising 100 parts by weight and having a load deflection temperature of 280 to 360 ° C.

  Furthermore, the present invention relates to glass fiber 5 having a number average fiber diameter of 4 to 8 μm and a number average fiber length of 100 to 200 μm with respect to 100 parts by weight of a wholly aromatic liquid crystal polymer having a crystal melting temperature of 310 to 410 ° C. The present invention relates to a liquid crystal polymer composition for molding an electronic component for surface mounting, which comprises ˜100 parts by weight and has a load deflection temperature of 280 to 360 ° C.

  The present invention also relates to a surface mounting method for a circuit board, in which the electronic component for surface mounting according to the present invention is mounted on a circuit board using a flux-containing cream solder.

  The liquid crystal polymer used in the present invention is a polyester or polyester amide that forms an anisotropic melt phase, and is referred to by those skilled in the art as a thermotropic liquid crystal polyester or a thermotropic liquid crystal polyester amide.

  The property of the anisotropic molten phase can be confirmed by a normal deflection inspection method using an orthogonal deflector, that is, by observing a sample placed on a hot stage in a nitrogen atmosphere.

  The liquid crystal polymer used in the present invention is a wholly aromatic liquid crystal polymer in which all the structural units in the polymer are composed of aromatic units and do not contain aliphatic units such as ethylenedioxy units.

  The liquid crystal polymer used in the present invention has a crystal structure in consideration of heat resistance to prevent thermal deformation during reflow at a high temperature during surface mounting, and moldability when molding a surface mounting electronic component with many thin portions. A liquid crystal polymer having a melting temperature (Tm) of 310 to 410 ° C, more preferably 310 to 370 ° C, and particularly preferably 310 to 340 ° C is used.

The crystal melting temperature of the liquid crystal polymer is measured by the method described below.
<Method for measuring crystal melting temperature>
Exstar 6000 manufactured by Seiko Instruments Inc. is used as a differential scanning calorimeter.
After measuring the endothermic peak temperature (Tm1) observed when the sample is measured from room temperature under a temperature rising condition of 20 ° C./min, the sample is held at a temperature 20 to 50 ° C. higher than Tm1 for 10 minutes. Next, the sample was cooled to room temperature under a temperature lowering condition of 20 ° C./min, and an endothermic peak when measured again under a temperature rising condition of 20 ° C./min was observed, and the temperature showing the peak top was determined as the crystal melting temperature ( Tm).

  As the repeating unit constituting the liquid crystal polymer used in the present invention, an aromatic oxycarbonyl repeating unit, an aromatic dicarbonyl repeating unit, an aromatic dioxy repeating unit, an aromatic aminooxy repeating unit, an aromatic aminocarbonyl repeating unit, an aromatic Aromatic units such as diamino repeat units and aromatic oxydicarbonyl repeat units.

  The liquid crystal polymer composed of each of these repeating units may or may not form an anisotropic molten phase depending on the constituent components, the composition ratio in the polymer, and the sequence distribution, but the liquid crystal used in the present invention. Polymers are limited to those that form an anisotropic melt phase.

  Specific examples of the monomer that gives an aromatic oxycarbonyl repeating unit include, for example, parahydroxybenzoic acid, metahydroxybenzoic acid, orthohydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, and 5-hydroxy-2-naphthoic acid. 3-hydroxy-2-naphthoic acid, 4'-hydroxybiphenyl-4-carboxylic acid, 3'-hydroxybiphenyl-4-carboxylic acid, 4'-hydroxybiphenyl-3-carboxylic acid, their alkyl, alkoxy or halogen Substituents and ester-forming derivatives thereof such as acylated products, ester derivatives, acid halides and the like can be mentioned. Among these, parahydroxybenzoic acid and 6-hydroxy-2-naphthoic acid are preferable from the viewpoint of easy adjustment of characteristics and melting point of the liquid crystal polymer.

  Specific examples of monomers that give aromatic dicarbonyl repeating units include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1, Examples thereof include aromatic dicarboxylic acids such as 4-naphthalenedicarboxylic acid and 4,4′-dicarboxybiphenyl, alkyl, alkoxy or halogen-substituted products thereof, and ester-forming derivatives such as ester derivatives and acid halides thereof. Among these, terephthalic acid and 2,6-naphthalenedicarboxylic acid are preferable because the liquid crystal polymer from which terephthalic acid and 2,6-naphthalenedicarboxylic acid are obtained can easily adjust the mechanical properties, heat resistance, melting point temperature, and moldability to appropriate levels.

  Specific examples of monomers that give aromatic dioxy repeating units include hydroquinone, resorcin, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 4 Aromatic diols such as 4,4'-dihydroxybiphenyl, 3,3'-dihydroxybiphenyl, 3,4'-dihydroxybiphenyl, 4,4'-dihydroxybiphenyl ether, alkyl, alkoxy or halogen substituents thereof, and Examples thereof include ester-forming derivatives such as acylated products. Among these, hydroquinone and 4,4′-dihydroxybiphenyl are preferable from the viewpoint of reactivity during polymerization, characteristics of the obtained liquid crystal polymer, and the like.

  Specific examples of the monomer that gives an aromatic aminooxy repeating unit include, for example, p-aminophenol, m-aminophenol, 4-amino-1-naphthol, 5-amino-1-naphthol, and 8-amino-2- Aromatic hydroxyamines such as naphthol and 4-amino-4′-hydroxybiphenyl, alkyl, alkoxy or halogen substituents thereof, and ester or amide-forming derivatives thereof such as acylated products thereof can be mentioned.

  Specific examples of the monomer that gives an aromatic diamino repeating unit include aromatic diamines such as p-phenylenediamine, m-phenylenediamine, 1,5-diaminonaphthalene, 1,8-diaminonaphthalene, alkyls thereof, Examples include amide-forming derivatives such as alkoxy or halogen-substituted products, and acylated products thereof.

  Specific examples of the monomer that gives an aromatic aminocarbonyl repeating unit include aromatic aminocarboxylic acids such as p-aminobenzoic acid, m-aminobenzoic acid, and 6-amino-2-naphthoic acid, their alkyls, Examples thereof include alkoxy or halogen-substituted products, and ester or amide-forming derivatives thereof such as acylated products, ester derivatives, and acid halides.

  Specific examples of monomers that give aromatic oxydicarbonyl repeating units include hydroxyaromatic dicarboxylic acids such as 3-hydroxy-2,7-naphthalenedicarboxylic acid, 4-hydroxyisophthalic acid, and 5-hydroxyisophthalic acid. And alkyl-substituted, alkoxy- or halogen-substituted products thereof, and ester-forming derivatives such as acylated products, ester derivatives, and acid halides thereof.

  The liquid crystal polymer used in the present invention may contain a thioester bond as long as the object of the present invention is not impaired. Examples of the monomer that gives such a bond include mercapto aromatic carboxylic acid, aromatic dithiol, and hydroxy aromatic thiol. The amount of these monomers used is aromatic oxycarbonyl repeating unit, aromatic dicarbonyl repeating unit, aromatic dioxy repeating unit, aromatic aminooxy repeating unit, aromatic diamino repeating unit, and aromatic oxydicarbonyl repeating unit. It is preferable that it is 10 mol% or less with respect to the total amount of the monomer which gives a unit.

  As mentioned above, although the repeating unit contained in the liquid crystal polymer used in this invention and the monomer which gives it were demonstrated, the liquid crystal polymer used in this invention is an aromatic oxycarbonyl repeating unit, 4-oxybenzoyl repeating unit, and / or Alternatively, it is more preferable to use one containing a 6-oxy-2-naphthoyl repeating unit because the mechanical properties of the liquid crystal polymer are excellent.

For liquid crystal polymers containing 4-oxybenzoyl repeat units and / or 6-oxy-2-naphthoyl repeat units, because of excellent moldability and heat resistance,
The total amount of 4-oxybenzoyl repeating units and 6-oxy-2-naphthoyl repeating units is preferably such that the ratio of the liquid crystal polymer to all repeating units is 50 to 80 mol%.

Among the liquid crystal polymers containing 4-oxybenzoyl repeating units and / or 6-oxy-2-naphthoyl repeating units, preferred are, for example, copolymers composed of the following monomer constituent units.
1) 4-hydroxybenzoic acid / 6-hydroxy-2-naphthoic acid copolymer 2) 4-hydroxybenzoic acid / terephthalic acid / 4,4'-dihydroxybiphenyl copolymer 3) 4-hydroxybenzoic acid / terephthalic acid / Isophthalic acid / 4,4'-dihydroxybiphenyl copolymer 4) 4-hydroxybenzoic acid / terephthalic acid / isophthalic acid / 4,4'-dihydroxybiphenyl / hydroquinone copolymer 5) 4-hydroxybenzoic acid / terephthalic acid / Hydroquinone copolymer 6) 6-hydroxy-2-naphthoic acid / terephthalic acid / hydroquinone copolymer 7) 4-hydroxybenzoic acid / 6-hydroxy-2-naphthoic acid / terephthalic acid / 4,4′-dihydroxybiphenyl Copolymer 8) 6-hydroxy-2-naphthoic acid / terephthalic acid / 4,4'-dihydroxybi Phenyl copolymer 9) 4-hydroxybenzoic acid / 6-hydroxy-2-naphthoic acid / terephthalic acid / hydroquinone copolymer 10) 4-hydroxybenzoic acid / 2,6-naphthalenedicarboxylic acid / 4,4′-dihydroxy Biphenyl copolymer 11) 4-hydroxybenzoic acid / terephthalic acid / 2,6-naphthalenedicarboxylic acid / hydroquinone copolymer 12) 4-hydroxybenzoic acid / 2,6-naphthalenedicarboxylic acid / hydroquinone copolymer 13) 4 -Hydroxybenzoic acid / 6-hydroxy-2-naphthoic acid / 2,6-naphthalenedicarboxylic acid / hydroquinone copolymer 14) 4-hydroxybenzoic acid / terephthalic acid / 2,6-naphthalenedicarboxylic acid / hydroquinone / 4,4 '-Dihydroxybiphenyl copolymer 15) 4-hydroxybenzoic acid / tere Taric acid / 4-aminophenol copolymer 16) 6-hydroxy-2-naphthoic acid / terephthalic acid / 4-aminophenol copolymer 17) 4-hydroxybenzoic acid / 6-hydroxy-2-naphthoic acid / terephthalic acid / 4-aminophenol copolymer 18) 4-hydroxybenzoic acid / terephthalic acid / 4,4'-dihydroxybiphenyl / 4-aminophenol copolymer

［式［１］〜式［４］において、ｐ、ｑ、ｒ、およびｓは、各繰返し単位の液晶ポリマー中での組成比（モル％）であり、以下の式を満たす；
６０≦ｐ＋ｑ≦７８
０．０５≦ｑ≦３
１１≦ｒ≦２０
１１≦ｓ≦２０］。 In these, since it is excellent in molding processability and heat resistance, it is more preferable to use the copolymer of 13) as a liquid crystal polymer.
13) 4-hydroxybenzoic acid / 6-hydroxy-2-naphthoic acid / 2,6-naphthalenedicarboxylic acid / hydroquinone copolymer is particularly excellent in heat resistance. What is comprised by the repeating unit represented by [4] is especially preferable.

[In Formula [1]-Formula [4], p, q, r, and s are composition ratios (mol%) in the liquid crystal polymer of each repeating unit, and satisfy | fill the following formula | equation;
60 ≦ p + q ≦ 78
0.05 ≦ q ≦ 3
11 ≦ r ≦ 20
11 ≦ s ≦ 20].

  The liquid crystal polymer in the present invention may be a blend of two or more liquid crystal polymers for the purpose of improving fluidity during molding.

  When two or more liquid crystal polymers are blended, the crystal melting temperature of the blended liquid crystal polymer mixture may be 310 to 410 ° C.

  The liquid crystal polymer described above has a load deflection temperature of 280 to 280 when glass fibers having a number average fiber diameter of 4 to 8 μm, which will be described later, are blended depending on the composition ratio of the repeating units and the sequence distribution in the resin. It is divided into those showing 360 ° C and those showing a load deflection temperature of less than 280 ° C or higher than 360 ° C, but those used in the present invention are more preferably those showing a load deflection temperature of 280-360 ° C. Indicates 280-340 ° C, particularly preferably 280-320 ° C.

  If the load deflection temperature of the liquid crystal polymer composition is less than 280 ° C., the heat resistance is not sufficient, and thermal deformation and warpage are likely to occur due to heating during reflow. When the load deflection temperature is higher than 360 ° C., the crystal melting temperature of the liquid crystal polymer to be used is usually too high, which causes a problem in the moldability of the surface mount electronic component.

Below, the measuring method of load deflection temperature is described.
<Load deflection temperature>
A strip-shaped test piece having a length of 127 mm, a width of 3.2 mm, and a thickness of 12.7 mm is formed using an injection molding machine (UH1000-110 manufactured by Nissei Plastic Industry Co., Ltd.), and this is used to comply with ASTM D648. , Measured at a load of 1.82 MPa and a heating rate of 2 ° C./min.

Hereinafter, a method for producing a liquid crystal polymer used in the present invention will be described.
The production method of the liquid crystal polymer used in the present invention is not particularly limited, and a known polycondensation method for forming an ester bond or an amide bond composed of a combination of the above monomers, for example, a melt acidosis method, a slurry polymerization method, or the like is used. Can do.

  The melt acidosis method is a preferred method for use in the method for producing a liquid crystal polymer used in the present invention, and this method first heats a monomer to form a molten liquid of a reactant, and then performs a reaction. Subsequently, a molten polymer is obtained. Note that a vacuum may be applied to facilitate removal of volatiles (for example, acetic acid, water, etc.) by-produced in the final stage of the condensation.

  The slurry polymerization method is a method of reacting in the presence of a heat exchange fluid, and the solid product is obtained in a state suspended in a heat exchange medium.

  In both cases of the melt acidification method and the slurry polymerization method, the polymerizable monomer component used in producing the liquid crystal polymer is a modified form in which hydroxyl groups and / or amino groups are acylated, that is, as a lower acylated product. It can also be used for the reaction. The lower acyl group preferably has 2 to 5 carbon atoms, more preferably 2 or 3 carbon atoms. Particularly preferred is a method using an acetylated product of the monomer in the reaction.

  The acylated product of the monomer may be prepared by separately acylating and synthesized in advance, or it may be generated in the reaction system by adding an acylating agent such as acetic anhydride to the monomer during the production of the liquid crystal polymer. it can.

  In any case of the melt acidification method or the slurry polymerization method, a catalyst may be used as needed during the reaction.

Specific examples of the catalyst include organotin compounds such as dialkyltin oxide (for example, dibutyltin oxide) and diaryltin oxide; antimony trioxide; titanium dioxide; organotitanium compounds such as alkoxytitanium silicate and titanium alkoxide; alkali or alkali of carboxylic acid Examples include earth metal salts (for example, potassium acetate); inorganic acid salts (for example, potassium sulfate); Lewis acid (for example, boron trifluoride); gaseous acid catalysts such as hydrogen halide (for example, hydrogen chloride).
The ratio of the catalyst used is usually 10 to 1000 ppm, preferably 20 to 200 ppm, based on the monomer weight.

  The liquid crystal polymers obtained by the polycondensation reaction in this manner are each extracted from the polymerization reaction tank in a molten state, and then processed into pellets, flakes, or powders.

  The obtained liquid crystal polymer in the form of pellets, flakes, or powders is substantially a solid phase under reduced pressure or in an inert gas atmosphere such as nitrogen or helium for the purpose of increasing molecular weight and improving heat resistance. You may heat-process in a state.

  The treatment temperature in the case of performing the heat treatment in the solid phase is not particularly limited as long as the liquid crystal polymer does not melt, but it is preferably 260 to 350 ° C, preferably 280 to 320 ° C.

  The liquid crystal polymer thus obtained is then used in the vicinity of the crystal melting temperature of the liquid crystal polymer using a Banbury mixer, kneader, uniaxial or biaxial extruder, etc. together with glass fibers having a number average fiber diameter of 4 to 8 μm. A liquid crystal polymer composition used as a molding material of the surface mount electronic component of the present invention is blended by melt kneading at a crystal melting temperature + 30 ° C.

  The glass fiber to be blended in the liquid crystal polymer composition used in the present invention may be a glass fiber having a number average fiber diameter of 4 to 8 μm and a cut fiber length of 2 mm to 4 mm. In order to obtain a liquid crystal polymer composition containing glass fibers having a desired fiber length, melt kneading conditions are set according to the cut fiber length of the glass fiber used, and the glass in the obtained liquid crystal polymer composition The number average fiber length of the fibers may be adjusted to 100 μm to 200 μm, more preferably 130 to 200 μm.

The number average fiber length of the glass fibers in the liquid crystal polymer composition after melt-kneading is measured by the method described below.
<Glass fiber length measurement method>
The liquid crystal polymer composition containing glass fibers is completely ashed, and the remaining glass fibers are sufficiently stirred and dispersed in a mixed solution of pure water and a surfactant. 1 ml of the mixed solution is taken out into a glass plate, the glass fiber is observed with a microscope, and the glass fiber length is measured. In this example, Olympus Corporation BX60 was used as a microscope, and the obtained image was taken in image analysis software (manufactured by MITANI Corporation, Win Roof), and the glass fiber length was measured.

  The amount of glass fiber used in the liquid crystal polymer composition used in the present invention is preferably 5 to 100 parts by weight, more preferably 10 to 80 parts by weight, and particularly preferably 20 to 70 parts by weight with respect to 100 parts by weight of the liquid crystal polymer. preferable.

  In the present invention, the liquid crystal polymer composition used as a molding material for surface-mounting electronic components is made of glass fiber for the purpose of improving the mechanical properties and surface characteristics of the molded product, as long as the object of the present invention is not impaired. In addition, a fibrous filler and / or a plate-like or powdery filler may be included.

  Specific examples of the fibrous filler used in the present invention are selected from the group consisting of silica alumina fiber, alumina fiber, carbon fiber, aramid fiber, potassium titanate fiber, aluminum borate fiber, and wollastonite. One or more types may be mentioned.

  The average fiber diameter of the fibrous filler used in the present invention is not particularly limited as long as the object of the present invention is not impaired, but is preferably 0.1 to 50 μm. When the cross section of the fibrous filler is not circular, the longest length between any two points on the outer periphery of the cross section of the fibrous filler is taken as the fiber diameter.

  Specific examples of the plate-like or powdery filler used in the present invention are selected from the group consisting of mica, graphite, calcium carbonate, dolomite, clay, glass flakes, glass beads, barium sulfate, titanium oxide, and diatomaceous earth. One or more of them may be mentioned.

  In the liquid crystal polymer composition of the present invention, the use amount of fibrous fillers other than glass fibers and / or plate-like or powdery fillers is 100 parts by weight of the liquid crystal polymer as the total amount of the fillers. It is 1-100 weight part with respect to it, More preferably, it is 1-80 weight part, Most preferably, it is 1-60 weight part.

  The liquid crystal polymer composition of the present invention may further contain other components as long as the object of the present invention is not impaired. Other components include, but are not limited to, higher fatty acids, higher fatty acid esters, higher fatty acid amides, higher fatty acid metal salts, polysiloxanes, fluororesins and other mold release agents; dyes, pigments and other colorants; antioxidants A heat stabilizer; an ultraviolet absorber; an antistatic agent; a surfactant; a fluidity improver, and the like, which may be added singly or in combination of two or more.

Those having an external lubricant effect such as higher fatty acid, higher fatty acid ester, higher fatty acid metal salt, and fluorocarbon surfactant may be previously adhered to the surface of liquid crystal polymer pellets during molding.
Here, the higher fatty acid means one having 10 to 25 carbon atoms.

  These fiber-like and / or plate-like or powder-like fillers, and other components, as well as the glass fiber, are used together with the liquid crystal polymer by using a Banbury mixer, a kneader, a single or twin screw extruder, etc. It may be blended into the liquid crystal polymer after being melt-kneaded at a temperature near the crystal melting temperature or from the crystal melting temperature + 30 ° C.

  As described above, the fibrous filler and / or the plate-like or powder-like filler, various additives, and other resin components that may be blended in the liquid crystal polymer composition used in the present invention have been described. As a molding material for an electronic component for mounting, a liquid crystal polymer composition having a load deflection temperature of 280 to 360 ° C. is used even when these components are blended with a liquid crystal polymer.

  Thus obtained glass having a number average fiber diameter of 4 to 8 μm and a number average fiber length of 100 to 200 μm with respect to 100 parts by weight of the wholly aromatic liquid crystal polymer having a crystal melting temperature of 310 to 410 ° C. A liquid crystal polymer composition comprising 5 to 100 parts by weight of a fiber and having a load deflection temperature of 280 to 360 ° C. is converted into a desired surface mounting electronic component by a known molding method using an injection molding machine, an extruder, or the like. And molded.

  Examples of suitable surface mount electronic components in the present invention include those selected from the group consisting of connectors, switches, relays, capacitors, coils, transformers, camera modules, antennas, and chip antennas.

  The surface-mounting electronic component of the present invention obtained as described above has very little flux increase even when surface mounting is performed using a cream solder containing flux. In particular, even when surface mounting is performed using lead-free solder having a high melting point of 200 to 250 ° C., the melting point is 200 to 250 ° C. because there is little warping deformation of the parts and less product defects due to flux rise. It is particularly preferably used as a surface mounting electronic component for lead-free solder.

Hereinafter, the cream solder used for surface mounting in the present invention will be described.
The solder component used for the cream solder used in the present invention is not particularly limited as long as it is conventionally used in surface mounting.
Specific examples of the solder used in the present invention include Sn-Ag-Cu solder, Sn-Ag solder, Sn-Cu solder, Sn-Ag-Cu-Bi solder, Sn-Ag-Bi-In. Lead-free solder such as Sn-Cu-Ni solder, Sn-Bi solder, or Sn-Zn solder, and lead-containing solder such as Sn-Pb eutectic solder. A plurality of these solders may be blended in cream solder.

  Among these solders, it is preferable to use lead-free solder in consideration of the regulation of the use of lead-containing solder in Europe, and Sn-Ag-Cu is excellent in heat-resistant fatigue characteristics among lead-free solders. It is more preferable to use a system solder.

  As a component of the flux used for the cream solder used in the present invention, for example, based on a resin component, an activator, an organic halogen compound, a thixotropic agent, an organic solvent, and the like are used.

  In addition to the above components, an antioxidant, a rust inhibitor, a chelating agent, a leveling agent, an antifoaming agent, a dispersant, a matting agent, a colorant, and the like may be added to the flux as desired.

  Specific examples of the resin component used in the flux include natural resins such as natural rosin, disproportionated rosin, polymerized rosin, or hydrogenated rosin, polyester resin, polyurethane resin, silicone resin, epoxy resin, oxetane resin, or A synthetic resin such as an acrylic resin can be used. These resins may be used in combination of two or more.

  Specific examples of the activator used in the flux include methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, dimethylamine, diethylamine, di-n-propylamine, diisopropylamine, di-n-butylamine. Hydrohalides, such as hydrochlorides, hydrobromides, of amines such as trimethylamine, triethylamine, tri-n-propylamine, triisopropylamine, monoethanolamine, diethanolamine, or triethanolamine; Malonic acid, succinic acid, adipic acid, glutaric acid, diethyl glutaric acid, pimelic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, diglycolic acid, capric acid, lauric acid, myristic acid, palmitic acid, linoleic acid, me Phosphate, stearic acid, arachidic acid, threonine acid behenyl, linolenic acid, benzoic acid, hydroxypivalic acid, dimethylolpropionic acid, citric acid, malic acid, carboxylic acid salts such as glyceric acid or lactic acid. These active agents may be used in combination of two or more.

  When these activators are blended in the flux, it is usually desirable to blend in a proportion of 30% by weight or less in the flux.

  Examples of the halogen contained in the organic halogen compound used in the flux include chlorine, bromine and iodine. Specific examples of the organic halide used in the flux include 3-bromo-1-propanol, 1,4 -Halogenated alcohols such as dibromo-2-butanol; ethyl bromoacetate, ethyl α-bromocaprylate, ethyl α-bromopropionate, ethyl β-bromopropionate, 9,10,12,13,15,16- Halogenated aliphatic carboxylic acid esters such as hexabromostearic acid methyl ester; 2,3-dibromosuccinic acid, halogenated aliphatic carboxylic acids such as 9,10,12,13,15,16-hexabromostearic acid; 4-stearoyloxybenzyl bromide, 4-stearoylaminobenzyl bromide Halogenated benzyl compounds such as bis; halogenated alkylamides such as bis (2,3-dibromopropyl) o-phthalamide, N, N, N ′, N′-tetra (2,3-dibromopropyl) succinamide; 1 Halogenated hydrocarbons such as bromo-3-methyl-1-butene, 2,2-bis [4- (2,3-dibromopropyl) -3,5-dibromophenyl] propane; bis (2,3-dibromo Halogen-containing ether compounds such as propyl) glycerol and trimethylolpropane bis (2,3-dibromopropyl) ether; halogenated ketones such as 2,4-dibromoacetophenone; N, N′-bis (2,3-dibromopropyl) ) Halogenated ureas such as urea; Halogenated sulfones such as α, α, α-tribromomethylsulfone Succinate compounds such as bis (2,3-dibromopropyl) succinate; isocyanurate compounds such as tris (2,3-dibromopropyl) isocyanurate. These organic halides may be used in combination of two or more.

  When these organic halogen compounds are blended in the flux, it is usually desirable to blend at a ratio of 20% by weight or less in the flux.

  Specific examples of the thixotropic agent used in the flux include polyolefin waxes such as castor wax (hardened castor oil); fatty acid amides such as m-xylylene bis stearamide; N-butyl-N′-stearyl urea, etc. Substituted urea waxes; polymer compounds such as polyethylene glycol, polyethylene oxide, methylcellulose, ethylcellulose, and hydroxyethylcellulose; inorganic particles such as silica particles and kaolin particles. These thixotropic agents may be used in combination of two or more.

  When these thixotropic imparting agents are blended in the flux, it is usually desirable to blend in the flux at a ratio of 30% by weight or less.

  Specific examples of organic solvents used in the flux include triethylene glycol monomethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, ethylene glycol monophenyl ether, diethylene glycol. Monophenyl ether, diethylene glycol monobutyl acetate, dipropylene glycol, diethylene glycol-2-ethylhexyl ether, α-terpineol, benzyl alcohol, 2-hexyldecanol, butyl benzoate, diethyl maleate, diethyl adipate, sebacic acid Diethyl, dibutyl sebacate, diethyl phthalate , Dodecane, tetradecene, dodecylbenzene, ethylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, hexylene glycol, 1,5-pentanediol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether acetate, propylene glycol monoethyl Examples include ether acetate, butyl carbitol acetate, 3-methoxybutyl acetate, triethylene glycol butyl methyl ether, and triacetin. These organic solvents may be used in combination of two or more.

  When these organic solvents are blended in the flux, it is usually desirable to blend in the flux at a ratio of 50% by weight or less.

  The cream solder containing the solder component and the flux component described above is applied on the circuit board, and then the surface mounting electronic component of the present invention is installed on the circuit board, and then heated and soldered by a reflow furnace, Implementation is done.

  As the reflow apparatus used in the surface mounting method of the present invention, any reflow apparatus conventionally used for surface mounting, such as an infrared method and a hot air heating method, may be used.

  What is necessary is just to set according to a conventional method as temperature conditions at the time of reflow.

  The glass fiber 5 having a number average fiber diameter of 4 to 8 μm and a number average fiber length of 100 to 200 μm with respect to 100 parts by weight of the wholly aromatic liquid crystal polymer having a crystal melting temperature of 310 to 410 ° C. Flux increase due to reflow at a high temperature by performing surface mounting using a surface mounting electronic component obtained by molding a liquid crystal polymer composition comprising 100 parts by weight and having a load deflection temperature of 280 to 360 ° C. Is greatly reduced.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to a following example at all.

Below, the symbol of the material used in the synthesis example, the Example, and the comparative example is demonstrated.
<Liquid crystal polymer monomer>
POB: 4-hydroxybenzoic acid BON6: 6-hydroxy-2-naphthoic acid NDA: 2,6-naphthalenedicarboxylic acid HQ: hydroquinone TPA: terephthalic acid

<Filler>
GF1: T-790 (glass fiber, manufactured by Nippon Electric Glass Co., Ltd., number average fiber diameter 6 μm, cut fiber length 3 mm)
GF2: PX-1 (glass fiber, manufactured by Asahi Fiber Glass Co., Ltd., number average fiber diameter 10 μm, number average fiber length 20 μm or 70 μm)
GF3: FT591 (glass fiber, manufactured by Asahi Fiber Glass Co., Ltd., number average fiber diameter 13 μm, cut fiber length 3 mm)
AB: YS3A (aluminum borate fiber, manufactured by Shikoku Kasei Kogyo Co., Ltd., fiber diameter 0.5 to 1.0 μm, average fiber length 10 to 30 μm)

[Synthesis Example 1]
POB: 234.8 kg (1699 mol), BON6: 0.9 kg (5 mol), HQ: 38.3 kg (348 mol), NDA: 75.2 kg (348 mol) and acetic anhydride: 254.3 kg (2491 mol) Was charged into a 0.5 m ³ SUS polymerization tank having a stirring blade and a heat exchanger, and the temperature was raised from room temperature to 145 ° C. over 1 hour in a nitrogen gas atmosphere, and kept at that temperature for 0.5 hour. did. Thereafter, the temperature was raised to 348 ° C. over 8 hours while acetic acid produced as a by-product was distilled off. After performing the polymerization reaction at the same temperature for 30 minutes, the pressure was reduced from normal pressure to 20 torr over 70 minutes at the same temperature. As a result of further continuing the polymerization under 20 torr for 30 minutes, a predetermined torque was reached. Therefore, the polymerization tank was sealed, and the inside of the polymerization tank was pressurized to 0.1 MPa with nitrogen gas to complete the reaction. Subsequently, the valve | bulb of the polymerization tank bottom part was opened, the die was passed through in the shape of a strand, and the pellet-like prepolymer (liquid crystal polymer with a low polymerization degree) was obtained.

  The crystal melting temperature of the obtained prepolymer measured by a differential scanning calorimeter was 331 ° C., and the melt viscosity was 16 Pa · s.

Charged prepolymer pellets 10kg at a temperature 200 ° C. for intracisternal the gaseous phase at a tumble dryer 40L, after the inside of the tank was N ₂ substitutions, 120L / N ₂ stream under hr, substantially solid while rotating at 15rpm The temperature in the tank was raised to 290 ° C. over 1 hour with the state kept, and solid state polymerization was performed at 290 ° C. for 5 hours. After completion of the reaction, the inside of the tank was cooled, the rotation was stopped, and the pellets were extracted.

  The crystal melting temperature of the obtained resin measured by a differential scanning calorimeter was 333 ° C.

[Synthesis Example 2]
POB: 195.9 Kg (1416.8 mol), BON6: 7.6 Kg (40.5 mol), HQ: 31.2 Kg (283.4 mol), NDA: 61.3 kg (283.4 mol) and acetic anhydride : 212.8 kg (2084.8 mol) was charged into a 0.5 m ³ SUS polymerization tank having a stirring blade and a heat exchanger, and the temperature was raised from room temperature to 145 ° C. over 1 hour in a nitrogen gas atmosphere. And held at the same temperature for 0.5 hour. Thereafter, the temperature was raised to 348 ° C. over 8 hours while acetic acid produced as a by-product was distilled off. After performing the polymerization reaction at the same temperature for 30 minutes, the pressure was reduced from normal pressure to 20 torr over 70 minutes at the same temperature. As a result of continuing the polymerization for 60 minutes under 20 torr, a predetermined torque was reached, so the polymerization tank was sealed, and the inside of the polymerization tank was pressurized to 0.1 MPa with nitrogen gas to complete the reaction. Subsequently, the valve | bulb of the polymerization tank bottom part was opened, the die | dye was extracted through the die | dye, and pellet-form resin was obtained.
The crystal melting temperature of the obtained resin measured by a differential scanning calorimeter was 323 ° C.

[Synthesis Example 3]
POB: 149.8 Kg (1084.9 mol), BON6: 74.9 Kg (398.2 mol), HQ: 57.6 Kg (523.5 mol), TPA: 87.0 kg (523.5 mol) and acetic anhydride : 266.0 kg (2606.0 mol) was charged into a 0.5 m ³ SUS polymerization tank having a stirring blade and a heat exchanger, and the temperature was raised from room temperature to 145 ° C. over 1 hour in a nitrogen gas atmosphere. And held at the same temperature for 0.5 hour. Thereafter, the temperature was raised to 348 ° C. over 8 hours while acetic acid produced as a by-product was distilled off. Subsequently, the pressure was reduced from normal pressure to 10 torr over 120 minutes at the same temperature. As a result of continuing the polymerization for 90 minutes under 10 torr, a predetermined torque was reached. Therefore, the polymerization tank was sealed, and the inside of the polymerization tank was pressurized to 0.1 MPa with nitrogen gas to complete the reaction. Subsequently, the valve | bulb of the polymerization tank bottom part was opened, the die | dye was extracted through the die | dye, and pellet-form resin was obtained.
The crystal melting temperature of the obtained resin measured by a differential scanning calorimeter was 330 ° C.

[Examples 1 to 4 and Comparative Examples 1 to 4]
Preparation of liquid crystal polymer composition Liquid crystal polymer and filler of the types and amounts described in Table 1 were mixed with a Henschel mixer, and then melt-kneaded with a twin-screw extruder (manufactured by Nippon Steel Co., Ltd., TEX-30α). The product was pelletized to prepare a liquid crystal polymer composition.
Table 2 shows the number average fiber length of the glass fibers in the liquid crystal polymer composition and the load deflection temperature (DTUL) value measured according to ASTM D648 of the obtained liquid crystal polymer composition.

Confirmation test of flux rise generation After the obtained liquid crystal polymer composition was dried at 150 ° C. for 4 hours, the cylinder temperature was 360 ° C. and the mold temperature was 90 ° C. using an injection molding machine (α-100iA, manufactured by FANUC CORPORATION). The molded product with metal terminals of 15 mm × 15 mm × 1 mm shown in FIG. The numerical values shown in FIG. 1 indicate dimensions (mm).

  After applying cream solder (M705-GRN360-K2-V, Sn-Ag-Cu solder used, solder melting point 219 ° C., manufactured by Senju Metal Industry Co., Ltd., solder melting point 219 ° C.) on the substrate, a molded product with metal terminals is installed and infrared Using a reflow device (SAI-2604M, manufactured by Senju Metal Industry Co., Ltd.), reflow was performed under the conditions that the treatment time at 200 ° C. or higher was 70 seconds, the treatment time at 230 ° C. or higher was 40 seconds, and the peak temperature was 260 ° C. The treatment was performed twice.

Remove the resin from the molded product with metal terminals after reflow treatment using tools such as nippers and pliers, and visually observe the occurrence of flux rise on the surface of the metal terminal portion, and check for defects due to flux rise. confirmed. The test was performed at n = 20.
Table 2 shows the incidence of defects due to flux increase.

Warp occurrence confirmation test Insert molding under the same conditions as the metal terminal molded product used in the flux rise occurrence confirmation test, and a connector molded product having a shape of 0.35 mm pitch × 80 cores × thickness 1 mm as shown in FIG. Was prepared. The numerical value in FIG. 2 shows a dimension (mm).
The obtained connector molded product was subjected to reflow treatment twice under the same conditions as in the confirmation test for flux rise.
After performing the reflow treatment, the coordinate measuring device (QVH250pro, manufactured by Mitutoyo Corporation) was used to measure the height of four sides of the connector molded product after the reflow treatment to measure the flatness. The results are shown in Table 2.

*1: 数平均繊維径
*2: 数平均繊維長

* 1: Number average fiber diameter
* 2: Number average fiber length

  From Table 2, load deflection temperature 280-360 which compounded the glass fiber of Examples 1-4 with the number average fiber diameter of 6 micrometers so that the number average fiber length of the glass fiber in a composition might be 100-200 micrometers. When the liquid crystal polymer composition at 0 ° C. was used, it was found that only a slight warpage of the electronic component for surface mounting occurred, and no defect due to flux increase was observed.

Molded product with metal terminal used in the flux rise confirmation test of the example. Dimensions of each part of the molded product with metal terminals in FIG. The perspective view of the connector molded article used for the confirmation test of generation | occurrence | production of the curvature of an Example. The dimension of each part of the connector molded product of FIG. 2-1.

Explanation of symbols

  A: Resin part B: Metal terminal

Claims (12)

  5 to 100 parts by weight of glass fibers having a number average fiber diameter of 4 to 8 μm and a number average fiber length of 100 to 200 μm with respect to 100 parts by weight of a wholly aromatic liquid crystal polymer having a crystal melting temperature of 310 to 410 ° C. An electronic component for surface mounting obtained by molding a liquid crystal polymer composition having a load deflection temperature of 280 to 360 ° C.   The electronic component for surface mounting according to claim 1, wherein the wholly aromatic liquid crystal polymer contains a 4-oxybenzoyl repeating unit and / or a 6-oxy-2-naphthoyl repeating unit.   The surface-mounting device according to claim 2, wherein the ratio of the total amount of 4-oxybenzoyl repeating units and 6-oxy-2-naphthoyl repeating units to all repeating units in the wholly aromatic liquid crystal polymer is 50 to 80 mol%. Electronic components. The surface-mount electronic component according to claim 3, wherein the wholly aromatic liquid crystal polymer is composed of repeating units represented by the following formulas [1] to [4].

[In Formula [1]-Formula [4], p, q, r, and s are composition ratios (mol%) in the liquid crystal polymer of each repeating unit, and satisfy | fill the following formula | equation;
60 ≦ p + q ≦ 78
0.05 ≦ q ≦ 3
11 ≦ r ≦ 20
11 ≦ s ≦ 20].   The electronic component for surface mounting according to any one of claims 1 to 4, wherein the electronic component for surface mounting is for mounting with a lead-free solder having a melting point of 200 to 250 ° C.   The surface-mounted electronic component according to claim 1, wherein the surface-mounting electronic component is selected from the group consisting of a connector, a switch, a relay, a capacitor, a coil, a transformer, a camera module, an antenna, and a chip antenna. Electronic components for mounting.   5 to 100 parts by weight of glass fibers having a number average fiber diameter of 4 to 8 μm and a number average fiber length of 100 to 200 μm with respect to 100 parts by weight of a wholly aromatic liquid crystal polymer having a crystal melting temperature of 310 to 410 ° C. A liquid crystal polymer composition for electronic components for surface mounting, comprising a load deflection temperature of 280 to 360 ° C.   The liquid crystal polymer composition for electronic components for surface mounting according to claim 7, wherein the wholly aromatic liquid crystal polymer contains a p-oxybenzoyl repeating unit and / or a 6-oxy-2-naphthoyl repeating unit.   The surface-mounting device according to claim 8, wherein the ratio of the total amount of the p-oxybenzoyl repeating unit and the 6-oxy-2-naphthoyl repeating unit to the total repeating unit in the wholly aromatic liquid crystal polymer is 50 to 80 mol%. Liquid crystal polymer composition for electronic parts. The liquid crystal polymer composition for electronic components for surface mounting according to claim 9, wherein the wholly aromatic liquid crystal polymer is composed of repeating units represented by the following formulas [1] to [4].

[In Formula [1]-Formula [4], p, q, r, and s are composition ratios (mol%) in the liquid crystal polymer of each repeating unit, and satisfy | fill the following formula | equation;
60 ≦ p + q ≦ 78
0.05 ≦ q ≦ 3
11 ≦ r ≦ 20
11 ≦ s ≦ 20].   A surface mounting method for a circuit board, wherein the surface mounting electronic component according to any one of claims 1 to 6 is mounted on a circuit board using a flux-containing cream solder.   The surface mounting method according to claim 11, wherein the solder is a lead-free solder having a melting point of 200 ° C. to 250 ° C.

Images