KR20080100790A - Surface mount type electronic components - Google Patents

Abstract

Surface mount type electronic components can cause more little flux migration in the soldering on the surface of a substrate like a circuit board. Surface mount type electronic components is produced by molding a liquid-crystalline polymer composition containing 100 parts by weight of aromatic liquid crystal polymer having a melting temperature of 310-410deg.C and 5-100 parts by weight of glass fiber having the number average diameter of 4-8 micrometer and number average length of 100-200 micrometer. The LCP composition has the deformation temperature(DTUL) of 280-360deg.C. The electronic component comprises the aromatic liquid crystal polymer having repeating units of 4-oxybenzoyl and/or 6-oxy-naphthoyl. The total amount of repeating units of 4-oxybenzoyl and/or 6-oxy-naphthoyl is 50-80 mole % based on the total repeating units of the liquid crystal polymer.

Description

Surface Mount Electronic Components {SURFACE MOUNT TYPE ELECTRONIC COMPONENTS}

BACKGROUND OF THE INVENTION The present invention relates to surface mount electronic components that result in less flux migration when mounted on the surface of a device such as a circuit board.

Thermoplastic liquid crystal polymers (hereinafter abbreviated as " LCP ") have good characteristics including heat resistance, mechanical properties such as strength, chemical resistance, and dimension precision. Because of these features, LCP is used in the manufacture of molded articles as well as in a variety of products including fibers and films.

In the field of telecommunications, very thin components are sometimes required. In particular, personal computers and mobile phones employ highly integrated devices and require the use of smaller, thinner and smaller components. Because of the superior features of LCP, the consumption of LCP has recently increased.

When manufacturing electronic devices, surface mount electronic components such as switches, relays, connectors, capacitors, coils, transformers, semiconductors, resistors, etc. are typically mounted on the surface of a substrate such as a circuit board by soldering. Let's do it. In the soldering process, a cream solder or solder paste is printed on a substrate, an electronic component is placed on the printed substrate, and the printed substrate is heated by a solder reflowing device to produce a soldering effect.

An LCP for manufacturing a surface mount electronic component is proposed (Japanese Patent Application Laid-open No. H08-143654). However, electronic components made of LCP suffer from some problems, such as bending of the component when soldering due to the higher reflow temperature. The curved parts easily cause flux migration in the cream solder to small gaps between the polymer and metal components caused by flux migration, that is, the bending due to capillary action.

In order to mount electronic components such as connectors on electronic devices, environmentally conscious lead-free solders are preferably used nowadays. For example, the RoHS (Restriction on the Use of Certain Hazardous Substances in Electronic and Electrical Products) was adopted by the European Union on 1 July 2006 to strictly limit the use of hazardous substances, including lead. To meet the above requirements, solder alloys used to mount electronic components on surfaces of materials such as circuit boards have been replaced with lead-free solder alloys.

Lead-free solder alloys such as Sn-Ag-Cu, Sn-Ag and Sn-Cu alloys have a reflow temperature of about 200-250 ° C., which is higher than conventional Sn-Pb solder alloys with a reflow temperature of about 180 ° C. . Due to the higher reflow temperature, soldering with lead-free solder alloys was generally performed at higher reflow temperatures.

Because of the higher reflow temperatures, the problem of flux migration when using cream solders containing lead-free solder alloys has become more pronounced, the problem of electronic components made from LCP.

To prevent the progression of warpage that causes flux migration, fiber fillers such as glass fibers and aluminum borate whiskers having a number average length of less than 100 μm, and lamellar fillers, such as talc, are added to the LCP composition. (Japanese Patent Application Laid-Open No. 2002-294038).

It is an object of the present invention to obtain surface mount electronic components which result in less flux migration when soldering at the surface of the substrate, such as a circuit board. It is yet another object of the present invention to provide an LCP composition suitable for manufacturing surface mount electronic components which results in less flux migration problems when soldering at the surface of the substrate.

Accordingly, the present invention provides a surface mount electronic component obtained by molding a liquid crystal polymer composition including the above, wherein the LCP composition provides a surface mount electronic component having a deformation temperature under load (DTUL) of 280-360 ° C. :

100 parts by weight of the wholly aromatic liquid crystal polymer having a crystal melting temperature of 310-410 ℃, and

5-100 parts by weight of glass fibers having a number average diameter of 4-8 μm and a number average length of 100-200 μm.

In another aspect of the invention, an LCP composition comprising: the LCP composition provides an LCP composition having a deformation temperature under load (DTUL) of 280-360 ° C .:

100 parts by weight of the wholly aromatic liquid crystal polymer having a crystal melting temperature of 310-410 ℃, and

5-100 parts by weight of glass fibers having a number average diameter of 4-8 μm and a number average length of 100-200 μm.

In a further aspect of the invention, a method of mounting an electronic component of the invention on a surface of a circuit board, comprising the step of soldering the component over the surface of the substrate using a cream solder comprising solder alloy and flux.

Best Mode for Carrying Out the Invention

The LCP used in the present invention is a liquid crystalline polyester or liquid crystalline polyester amide, which exhibits an anisotropic molten phase and is called a thermotropic LCP in the art.

The anisotropic molten phase of the LCP can be confirmed by a conventional polarization system using a quadrature polarizer. In more detail, samples can be observed under a Leitz's polarization microscope on a Leitz's sign under a nitrogen atmosphere.

LCP used in the present invention is a wholly aromatic liquid crystal polymer whose molecular chain is composed of aromatic groups and does not contain aliphatic repeating units such as ethylene dioxy units.

The LCP used in the present invention has a crystal melting temperature (Tm) of 310-410 ° C., preferably 310-370 ° C. and in particular 310-340 ° C.

In the present specification and claims, the crystal melting temperature is a value determined by the following method:

<Method of Determining Crystal Melting Temperature>

Differential scanning calorimeter (DSC) Exstar 6000 (manufactured by Seiko Instruments, Chiba, Japan) or a DSC device of the same type was used. The LCP sample to be tested was heated from room temperature at a rate of 20 ° C./min and an endothermic peak (Tm1) was recorded. The sample was then held for 10 minutes at a temperature of 20-50 ° C. higher than Tm1. The sample was then cooled to room temperature at a rate of 20 ° C./min and heated again at a rate of 20 ° C./min. The endothermic peak found in the final process was recorded as the crystal melting temperature (Tm) of the sample LCP.

Examples of repeating units in the LCP are aromatic oxycarbonyl, aromatic di-carbonyl, aromatic dioxy, aromatic aminooxy, aromatic aminocarbonyl, aromatic diamino and aromatic oxydicarbonyl repeat units.

The LCP composed of the repeating units described above may include both those which form an anisotropic molten phase and those which do not form, depending on the constituent and composition ratio and sequence distribution of the polymer. LCPs used for the present invention are limited to those which form an anisotropic molten phase.

Examples of monomers providing aromatic oxycarbonyl repeat units include p-hydroxybenzoic acid, m-hydroxybenzoic acid, o-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 5-hydroxy-2-naphthoic acid , 3-hydroxy-2-naphthoic acid, 4'-hydroxybiphenyl-4-carboxylic acid, 3'-hydroxybiphenyl-4-carboxylic acid, 4'-hydroxybiphenyl-3-carbox Acids, and ester-forming derivatives such as their alkyl-, alkoxy- or halogen-substituted derivatives as well as their acyl derivatives, ester derivatives and acyl halides. Among these, p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid are preferable at the point which is easy to adjust the characteristic and melting | fusing point of the obtained LCP.

Examples of monomers providing aromatic di-carbonyl repeating units include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1 Aromatic dicarboxylic acids such as 4-naphthalenedicarboxylic acid, 4,4'-dicarboxybiphenyl, and their alkyl-, alkoxy or halogen-substituted derivatives as well as their acyl derivatives, ester derivatives and acyl halides Ester-forming derivatives. Among these, terephthalic acid and 2,6-naphthalenedicarboxylic acid are preferable at the point which is easy to adjust the mechanical property, heat resistance, melting | fusing point, and moldability of the obtained LCP.

Examples of monomers providing aromatic dioxy repeat units include hydroquinone, resorcin, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1,4 Aromatic diols such as dihydroxynaphthalene, 4,4'-dihydroxybiphenyl, 3.3'-dihydroxybiphenyl, 3,4'-dihydroxybiphenyl, 4.4'-dihydroxybiphenyl ether And ester-forming derivatives such as their acyl derivatives, ester derivatives and acyl halides, as well as their alkyl-, alkoxy or halogen-substituted derivatives. Of these, hydroquinone and 4,4'-dihydroxybiphenyl are preferred in view of good reactivity during the polarization step and good characteristics of the resulting LCP.

Examples of monomers providing aromatic aminooxy repeat units include p-aminophenol, m-aminophenol, 4-amino-1-naphthol, 5-amino-1-naphthol, 8-amino-2-naphthol, 4-amino- Such as aromatic hydroxyamines such as 4'-hydroxybiphenyl and their alkyl-, alkoxy or halogen-substituted derivatives, as well as ester-forming derivatives such as their acyl derivatives, ester derivatives and acyl halides and their N-acyl derivatives Amide forming derivatives.

Examples of monomers providing aromatic diamino repeat units include aromatic diamines such as p-phenylenediamine, m-phenylenediamine, 1,5-diaminonaphthalene, 1,8-diaminonaphthalene and their alkyl-, alkoxy or Amide forming derivatives such as halogen-substituted derivatives as well as their N-acyl derivatives.

Examples of monomers providing aromatic aminocarbonyl repeating units include aromatic aminocarboxylic acids such as p-aminobenzoic acid, m-aminobenzoic acid, 6-amino-2-naphthoic acid, and their alkyl-, alkoxy or halogen-substituted derivatives As well as ester-forming derivatives such as their acyl derivatives, ester derivatives and acyl halides and amide-forming derivatives such as their N-acyl derivatives.

Examples of monomers that provide aromatic oxydicarbonyl repeat units are hydroxy-aromatic dicars such as 3-hydroxy-2,7-naphthalenedicarboxylic acid, 4-hydroxyisophthalic acid, 5-hydroxyisophthalic acid. Ester-forming derivatives such as acids and their alkyl-, alkoxy or halogen-substituted derivatives as well as their acyl derivatives, ester derivatives and acyl halides.

LCP used in the present invention may have a thioester bond as long as the bond does not impair the object of the present invention. Examples of monomers providing thioester bonds are mercapto-aromatic carboxylic acids, aromatic dithiols and hydroxy-aromatic thiols. The ratio of said additional monomers is 10 mole% or less based on the total amount of monomers providing aromatic oxycarbonyl, aromatic di-carbonyl, aromatic dioxy, aromatic aminooxy, aromatic diamino and aromatic oxy di-carbonyl repeat units. It is preferable.

Among the above, the LCP used in the present invention includes aromatic oxycarbonyl repeating units containing 4-oxybenzoyl repeating units and / or 6-oxy-2-naphthoyl repeating units in terms of good mechanical properties of the obtained LCP. It is preferable.

In a preferred embodiment, in terms of the good moldability and thermal stability of the resulting LCP, the molar ratio of the total amount of 4-oxybenzoyl and 6-oxy-2-naphthoyl repeat units is 50-80 based on the total amount of repeat units in the LCP. It is preferable that it is mol%.

Examples of preferred LCPs that include 4-oxybenzoyl and 6-oxy-2-naphthoyl repeat units can include:

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'-dihydroxybiphenyl copolymer,

9) 4-hydroxybenzoic acid / 6-hydroxy-2-naphthoic acid / terephthalic acid / hydroquinone copolymer,

10) 4-hydroxybenzoic acid / 2,6-naphthalene dicarboxylic acid / 4,4'-dihydroxybiphenyl copolymer,

11) 4-hydroxybenzoic acid / terephthalic acid / 2,6-naphthalene dicarboxylic acid / hydroquinone copolymer,

12) 4-hydroxybenzoic acid / 2,6-naphthalene dicarboxylic acid / hydroquinone copolymer,

13) 4-hydroxybenzoic acid / 6-hydroxy-2-naphthoic acid / 2,6-naphthalene dicarboxylic acid / hydroquinone copolymer,

14) 4-hydroxybenzoic acid / terephthalic acid / 2,6-naphthalene dicarboxylic acid / hydroquinone / 4,4'-dihydroxybiphenyl copolymer,

15) 4-hydroxybenzoic acid / terephthalic 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, and

18) 4-hydroxybenzoic acid / terephthalic acid / 4,4'-dihydroxybiphenyl / 4-aminophenol copolymer,

Among the above, the copolymer of 13) is particularly preferable in view of the moldability and thermal stability of the polymer. As the copolymer of 13), a copolymer satisfying the following formula is preferably used in view of good thermal stability of the LCP obtained:

[Wherein p, q, r and s represent the molar ratio (mol%) of each of the repeating units (I)-(IV) in the LCP and satisfy the following formula:

60≤p + q≤78

0.05≤q≤3

11≤r≤20

11≤s≤20

p + q + r + s = 100].

The LCP of the present invention can be, for example, a polymer blend comprising two or more LCPs for the purpose of increasing the flowability of the LCP composition upon molding.

When employing a polymer blend, the crystal melting temperature of the polymer blend should be in the range 310-410 ° C.

The LCP composition of the present invention is provided with the LCP described above and glass fibers having a number average diameter of 4-8 μm. The LCP composition obtained as above may include those having a DTUL of less than 280 ° C or more than 360 ° C as well as those having a 280-360 ° C DTUL. According to the invention, LCP compositions having a DTUL of 280-360 ° C., preferably 280-340 ° C. and more preferably 280-320 ° C. are used.

LCP compositions with a DTUL of less than 280 ° C. do not exhibit sufficient thermal stability and may cause degradation or warpage due to reflow soldering performed at high temperatures. LCP compositions with DTULs above 360 ° C. generally have a too high crystal melting temperature and are not suitable for forming parts.

In the present specification and claims, DTUL (load deformation temperature) is a value determined according to the following method.

<How to determine strain temperature under load>

Test strips of LCP compositions having a length of 127 mm, a width of 3.2 mm, and a thickness of 12.7 mm were molded using an injection molding machine (UH 1000-110, manufactured by Nissei Plastic Industries, Nagano, Japan). . The strain temperature was measured using a test strip according to ASTM D 648 under a load of 1.82 MPa and a heating rate of 2 ° C./min.

The method for producing the LCP used in the present invention is not limited, and any method known in the art may be adopted. For example, conventional condensation polymerization methods for producing polymers, such as melt addition reaction methods and slurry polymerization methods, which provide ester and / or amide bonds in the monomer component can be employed.

The melt addition reaction method is preferably used for the production of LCP. In this method, the monomers are heated to provide a melt and then the solution is reacted to provide a molten polymer. The final process of the process can be carried out under vacuum to facilitate the removal of volatile byproducts such as acetic acid and water.

The slurry polymerization process is characterized by the reaction of monomers in a heat-exchange fluid to provide a solid polymer in suspension form in a heat-exchange liquid medium.

In either the melt addition reaction method or the slurry polymerization method, the polymerization monomer may be in the form of a lower acyl derivative obtained by acylating hydroxy and / or amino groups. Lower acyl groups may preferably have 2-5, more preferably 2-3 carbon atoms. Acetylated monomers are most preferred for use in the reaction.

The lower acyl derivative of the monomer may be prepared in advance by independently acylating the monomer, or may be prepared in a reaction system by adding an acylating agent such as acetic anhydride to the monomer when preparing the LCP.

In either the melt addition reaction method or the slurry polymerization method, a catalyst can be used if necessary.

Examples of catalysts include organic tin compounds such as dialkyl tin oxides (eg dibutyl tin oxide) and diaryl tin oxides; Organic titanium compounds such as titanium dioxide, antimony trioxide, alkoxy titanium silicates and titanium alkoxides; Alkali or alkaline earth metal salts of carboxylic acids such as potassium acetate; Salts of inorganic acids (eg, K ₂ SO ₄ ); Lewis acids (eg BF ₃ ) and gaseous acid catalysts such as hydrogen halide (eg hydrochloric acid).

When a catalyst is used, the amount of catalyst added to the reaction may be preferably 10-1000 ppm based on the total amount of monomers, more preferably 20-200 ppm.

LCP can be obtained from the polymerization reaction vessel in the molten state and then processed into pellets, flakes or powder.

The LCP in the form of pellets, flakes or powders can be heat treated in the essentially solid phase under vacuum or inert gas such as nitrogen or helium atmosphere, if necessary. The heat treatment temperature is not particularly limited as long as the LCP maintains a solid phase, and may be 260-350 ° C and preferably 280-320 ° C.

The LCP composition of the present invention is prepared by adding glass fibers having a number average diameter of 4-8 μm to the LCP and using a kneading machine such as a Banbury mixer, kneader, single screw extruder, screw extruder, or the like. Can be obtained at a temperature of near the crystal melting temperature (Tm) to Tm + 30 ° C by melt kneading.

The glass fibers added and mixed to the LCP may have a number average diameter of 4-8 μm and a cut length of 2-4 mm. In order to provide an LCP composition comprising glass fibers of a preferred length, the number average length of the glass fibers in the LCP composition obtained by applying the melt kneading conditions is 100-200 µm, preferably 130-200 µm.

The number average length of the glass fibers in the LCP composition obtained by the melt kneading of the LCP and the glass fibers is determined as follows.

<Method for determining glass fiber length in LCP composition>

The LCP composition comprising the glass fibers is burned to ashes. The remaining glass fibers in the ash are well dispersed in a mixture of purified water and surfactant. 1 ml of the mixed solution is placed on a glass plate and the length of the glass fibers during dispersion is measured under a microscope. In the examples and comparative examples of the present application, image data of dispersion was obtained using microscope BX60 (manufactured by Olympus, Tokyo, Japan) and image data using image analysis software Winloop (manufactured by Mitani, Tokyo, Japan). Analyze the length of the glass fibers.

According to the invention, the amount of glass fibers in the LCP composition is preferably 5-100 parts by weight, more preferably 10-80 parts by weight and especially 20-70 parts by weight per 100 parts by weight of LCP.

The LCP composition of the present invention may comprise further fillers selected from fibrous, lamellae and powder fillers in addition to glass fiber fillers for better mechanical or surface characterization of molded articles made from LCP compositions.

Examples of fibrous fillers may include silica-alumina fibers, alumina fibers, carbon fibers, aramid fibers, potassium titanate fibers, aluminum borate fibers, and wollastonite.

The average diameter of the fiber filler further used in the present invention is not particularly limited as long as it does not impair the object of the present invention, but 0.1-50 μm may be preferable. If the cross section of the fiber filler is not a circle, "diameter" represents the longest distance between two points of the filler cross section.

Examples of lamellae and powder fillers are mica, graft, calcium carbonate, dolomite, clay, glass flakes, glass beads, barium sulphate, titanium oxides and diatomite It may include.

The total amount of additional filler in the LCP composition of the present invention may be 1-100 parts by weight, preferably 1-80 parts by weight and most preferably 1-60 parts by weight per 100 parts by weight of LCP.

The LCP composition of the present invention may further include one or more additives conventionally used for the resin composition as long as it does not impair the object of the present invention. Molding lubricants such as, for example, higher fatty acids, higher fatty esters, higher fatty amides, higher fatty acid metal salts, polysiloxanes and fluorocarbon resins; Coloring agents such as dyes and pigments; Antioxidants; Heat stabilizers; UV absorbers; Antistatic agents; And surface active agents may be admixed.

Molding lubricants, such as higher fatty acids, higher fatty esters, higher fatty acid metal salts or fluorocarbon type surfactants, are added to the pellets of the LCP composition before the pellets are introduced into the molding process and as a result the formulation adheres to the outer surface of the pellets. The term "high fat" as used herein refers to those having a C10-C25 aliphatic moiety.

Adding fibrous, lamella or powder fillers and additional ingredients to the LCP composition, at temperatures from near the crystal melting temperature (Tm) to Tm + 30 ° C., kneaders such as Banbury mixers, kneaders, single screw extruders, screw The mixture may be melt kneaded using an extruder or the like.

According to the present invention, LCP compositions comprising fibrous, lamella or powder fillers and / or additional ingredients in addition to glass fiber fillers should have a DTUL in the range of 280-360 ° C.

Thus, the obtained LCP composition having a DTUL of 280-360 ° C. comprising the following obtains the desired surface mount electronic component using conventional methods such as injection molding, compression molding, extrusion molding and injection molding. : 100 parts by weight of a wholly aromatic liquid crystal polymer having a crystal melting temperature of 310-410 ° C., and 5-100 parts by weight of glass fiber having a number average diameter of 4-8 μm and a number average length of 100-200 μm.

Examples of surface mount electronic components provided by the present invention include switches, relays, connectors, capacitors, coils, transformers, camera modules, antennas, and chip antennas.

The electronic component of the present invention is properly soldered onto a surface of a substrate such as a rotating substrate with a cream solder containing a solder alloy and a flux. Electronic components of the present invention result in lower flux migration even when soldered with lead-free cream solders with melting points of 200-250 ° C. Even with such high temperatures, the electronic components of the present invention have no warpage or only small warpage, which results in less flux migration problems.

Suitable cream solders used to solder the electronic components of the present invention on the surface of a substrate such as a circuit board are as described below.

The cream solder may be any of those conventionally used for surface mount electronic components. Examples of solder alloys included in the cream solder include Sn-Ag-Cu, Sn-Ag, Sn-Cu, Sn-Ag-Cu-Bi, Sn-Ag-Bi-In, Sn-Cu-Ni, Sn-Bi, and Lead-free solder alloys such as Sn-Zn, and lead-containing solder alloys such as Sn-Pb eutectic solders.

Of the solder alloys, it is preferable to use lead-free solder alloys in view of the restrictions on the use of RoHS lead in the European Union. Of the lead-free solder alloys, Sn-Ag-Cu alloys are more preferable in view of excellent heat resistance and fatigue resistance.

Cream solders used in the present invention include solder alloys and fluxes. The flux may include resins, organic halogenated compounds, thixotropic agents and organic solvents that are the basis of the flux and the activator.

In addition to the above materials, the flux may, if desired, further comprise one or more optional additives including antioxidants, anticorrosive agents, chelating agents, leveling agents, antifoaming agents, dispersing agents, frosting agents, and coloring agents. It may include.

Examples of resins in the flux include natural resins such as natural rosin, unbalanced rosin, polymerized rosin and hydrogenated rosin; And synthetic resins such as polyesters, polyurethanes, silicones, epoxies, oxetane, and acrylic resins. Such resins may be used alone or in combination of two or more.

Examples of activators in the flux are methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, dimethylamine, diethylamine, di-n-propylamine, diisopropylamine, di-n- Salts of amine compounds such as butylamine, trimethylamine, triethylamine, tri-n-propylamine, triisopropylamine, monoethanolamine, diethanolamine or triethanolamine; And acids, such as hydrogen halides such as hydrochloric acid and hydrobromic acid, or oxalic acid, malonic acid, succinic acid, adipic acid, glutaric acid, diethylglutaric acid, pimeric acid, azelaic acid, sebacic acid, maleic acid , Fumaric acid, diglycolic acid, caprylic acid, lauric acid, myristic acid, palmitic acid, linoleic acid, oleic acid, stearic acid, arachidic acid, behenic acid, linolenic acid, benzoic acid, hydroxypivalic acid, dimethylolpropionic acid, citric acid Carboxylic acids such as, malic acid, glyceric acid and lactic acid. Activators can be used alone or in combination of two or more.

The flux in the cream solder used in the present invention may preferably comprise less than 30% by weight of activator based on the total amount of flux.

The organic halogenated compound contained in the flux may be a compound comprising chlorine, bromine or iodine. Examples of organic halogenated compounds include halogenated alcohols such as 3-bromo-1-propanol and 1,4-dibromo-2-butanol, halogenated aliphatic carboxylate esters such as ethyl bromoacetate, ethyl α-bromocaprylate, ethyl α-bromopropionate, ethyl β-bromopropionate, methyl 9,10,12,13,15,16-hexabromostearate; Halogenated aliphatic carboxylic acids such as 2,3-dibromosuccinic acid and 9,10,12,13,15,16-hexabromostearic acid; Halogenated benzyl such as 4-stearoyloxybenzyl bromide and 4-stearoylaminobenzyl bromide; Halogenated alkylamides such as bis (2,3-dibromopropyl) -o-phthalamide, N, N, N ', N'-tetra (2,3-dibromopropyl) succinamide; Halogenated hydrocarbons such as 1-bromo-3-methyl-1-butene, 2,2-bis [4- (2,3-dibromopropyl) -3,5-bromophenyl] propane; Halogenated ethers such as bis (2,3-dibromopropyl) glycerol and trimethylolpropane bis (2,3-dibromopropyl) ether; Halogenated ketones such as 2,4-dibromoacetophenone; Halogenated ureas such as N, N'-bis (2,3-dibromopropyl) urea; Halogenated sulfones such as α, α, α-tribromomethyl sulfone; Succinates such as bis (2,3-dibromopropyl) succinate; And isocyanurates such as tris (2,3-dibromopropyl) isocyanurate. Organic halogenated compounds may be used alone or in combination of two or more.

The flux of the cream solder used in the present invention may preferably comprise 20% by weight or less of the organic halogenated compound based on the total amount of the flux.

Examples of thixotropic agents contained in the flux are polyolefin waxes such as castor wax; Fatty acid amides such as m-xylene bis stearamide; Substituted urea waxes such as N-butyl-N'-stearyl urea; Polymers such as polyethylene glycol, polyethylene oxide, methyl cellulose, ethyl cellulose and hydroxyethyl cellulose; And inorganic particles such as silica and kaolin. The thixotropic agents may be used alone or in combination of two or more.

The flux in the cream solder used in the present invention may preferably comprise up to 30% by weight of thixotropic agent based on the total amount of flux.

Examples of the organic solvent contained 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, and 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, butylbenzo Eate, diethyl maleate, diethyl adipate, diethyl sebacate, dibutyl sebacate, dibutyl phthalate, dodecane, tetradecane, dodecylbenzene, ethylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol To hexylene glycol, 1,5-pentanediol, methylcarbitol, butylcarbitol, and propylene glycol monomethyl Le acetate, may include propylene glycol monomethyl ether acetate, butyl carbitol acetate, 3-methoxybutyl acetate, triethylene glycol butyl methyl ether, and triacetin. The organic solvent may be used alone or in combination of two or more.

The flux in the cream solder used in the present invention may preferably comprise up to 50% by weight of organic solvent, based on the total amount of flux.

The above-described cream solder is applied to a substrate such as a circuit board to mount the electronic component of the present invention on the substrate, and then heat-fix the substrate to the reflow soldering device to produce a soldering effect.

According to the present invention, the reflow soldering device used in the reflowing process may be any of those conventionally used to surface mount electronic components in circuit boards including an infrared reflow soldering device and a forced-vent convection reflow soldering device. It may be of.

The temperature of the reflow soldering process can be determined in a conventional manner.

The electronic components of the present invention can undergo less warpage even after reflow soldering at higher temperatures, and can be mounted with lead-free solder on the surface of the substrate with little or no flux migration.

The invention is further described with reference to the following examples. The following examples are intended to illustrate the invention but are not to be construed as limiting the scope of the invention.

In the following examples and comparative examples, the following abbreviations are used.

POB: 4-hydroxybenzoic acid

BON6: 6-hydroxy-2-naphthoic acid

NDA: 2,6-naphthalene dicarboxylic acid

HQ: hydroquinone

TPA: terephthalic acid

Fiberglass / additional Filling

GF1: Glass fiber T-790 (made by Nippon Electric Glass Co., Ltd., Shiga, Japan), Number average diameter: 6 micrometers, Cut length: 3 mm.

GF2: Glass fiber PX-1 (made by Asahi Fiber Glass Co., Tokyo, Japan), Number average diameter: 10 micrometers, Number average length: 20 micrometers / 70 micrometers

GF3: Glass fiber FT591 (made by Asahi Fiber Glass Co., Tokyo, Japan), Number average diameter: 13 micrometers, Cut length: 3 mm

AB: Aluminum borate fiber YS3A (Shikoku Chemical Co., Ltd., Kagawa, Japan) Diameter: 0.5-1.0 micrometer, Average length: 10-30 micrometers

synthesis Example  One: LCP  One

SUS 234.8 kg (1699 moles), BON6 0.9 kg (5 moles), HQ 38.3 kg (348 moles), NDA 75.2 kg (348 moles) and 254.3 kg (2491 moles) acetic anhydride, equipped with a stirrer and heat exchange Filled into a 0.5 m ³ polymerization container. Under a nitrogen gas atmosphere, the mixture was heated from room temperature to 145 ° C. over 1 hour and held at that temperature for 0.5 hours. The mixture was then heated to 348 ° C. over 8 hours, at which temperature the by-products, acetic acid and polymers were distilled off for 30 minutes, and the air pressure in the polymerization container was then decompressed over 70 minutes at atmospheric pressure to 20 Torr. The reaction was further performed at this pressure for 30 minutes. After 30 minutes, the polymerization container was sealed when the torque of the reaction reached a predetermined level. Nitrogen gas was introduced into the container to terminate the reaction, resulting in an increase in atmospheric pressure of 0.1 MPa. The valve was opened at the bottom of the polymerization container and the contents of the container were drawn through a die to obtain a strand of prepolymer, i.e. a liquid crystal polymer having a low degree of polymerization, and the prepolymer was cut to obtain pellets.

The crystal melting temperature of the initial polymer determined by the differential scanning calorimeter was 331 占 폚 and the melt viscosity was 16 Pa · s.

Pellets of 10 kg of the obtained prepolymer were charged into a 40 L-tumble dryer vessel made of SUS. The gas phase in the container was kept at 200 ° C. The gas phase was exchanged with nitrogen gas, rotated at 15 rpm under 120 L / hour nitrogen gas flow and the temperature in the vessel was increased to 290 ° C. over 1 hour while keeping the pellets solid. Solid phase polymerization was achieved at this temperature for 5 hours. After completion of the reaction, the vessel was cooled and the rotation stopped and a pellet of LCP 1 was obtained.

The crystal melting temperature of LCP 1 was 333 deg.

synthesis Example  2: LCP  2

SUS 195.9 kg (1416.8 mole), BON6 7.6 kg (40.5 mole), HQ 31.2 kg (283.4 mole), NDA 61.3 kg (283.4 mole) and 212.8 kg (2084.8 mole) acetic anhydride, equipped with stirring device and heat exchange Filled into a 0.5 m ³ polymerization container. Under a nitrogen gas atmosphere, the mixture was heated from room temperature to 145 ° C. over 1 hour and held at that temperature for 0.5 hours. The mixture was then heated to 348 ° C. over 8 hours, at which temperature the by-products, acetic acid and polymers were distilled off for 30 minutes, and the air pressure in the polymerization container was then decompressed over 70 minutes at atmospheric pressure to 20 Torr. The reaction was further performed at this pressure for 60 minutes. After 60 minutes, the polymerization container was sealed when the torque of the reaction reached a predetermined level. Nitrogen gas was introduced into the container to terminate the reaction, resulting in an increase in atmospheric pressure of 0.1 MPa. The valve was opened at the bottom of the polymerization container and the contents of the container were pulled through a die to obtain strands of liquid crystal polymer, which were then cut off to obtain pellets of LCP 2.

The crystal melting temperature of LCP 2 determined by the differential scanning calorimeter was 323 ° C.

synthesis Example  3: LCP  3

SUS 149.8 kg (1084.9 moles), BON6 74.9 kg (398.2 moles), HQ 57.6 kg (523.5 moles), TPA 87.0 kg (523.5 moles) and 266.0 kg (2606.0 moles) acetic anhydride, with stirring device and heat exchange Filled into a 0.5 m ³ polymerization container. Under a nitrogen gas atmosphere, the mixture was heated from room temperature to 145 ° C. over 1 hour and held at that temperature for 0.5 hours. The mixture was then heated to 348 ° C. over 8 hours and the by-product, acetic acid was distilled off at this temperature for 30 minutes. The air pressure in the polymerization container was then decompressed over 10 minutes at atmospheric pressure to 10 Torr. The reaction was further performed at this pressure for 90 minutes. After 90 minutes, the polymerization container was sealed when the torque of the reaction reached a predetermined level. Nitrogen gas was introduced into the container to terminate the reaction, resulting in an increase in atmospheric pressure of 0.1 MPa. The valve was opened at the bottom of the polymerization container and the contents of the container were pulled through a die to obtain strands of the liquid crystal polymer which were then cut off to obtain pellets of LCP 3.

The crystal melting temperature of LCP 3 determined by the differential scanning calorimeter was 330 ° C.

Example  1-4 and comparison Example  1-4

Preparation of LCP Composition

The LCP and fillers shown in Table 1 were mixed using a Henschel mixer and then kneaded using an extruder (TEX30 α-35BW-2V, manufactured by Japan Works, Tokyo, Japan) to form pellets. LCP compositions were provided.

The number average length of glass fibers contained in the LCP composition and the DTUL of the LCP composition under ASTM D648 were determined and shown in Table 2.

Flux Migration  exam

The obtained LCP composition was dried at 150 ° C. for 4 hours, and then molded at a cylinder temperature of 360 ° C. and a die temperature of 90 ° C. using an injection molding machine (α-100iA, Funakase, Yamanashi, Japan) to obtain a resin portion ( A test piece having a metal end (B) sandwiched in A) was obtained. The size of the resin portion (A) of the test piece was 15 mm X 15 mm X 1 mm. The exact shape and size of the test piece is shown in FIGS. 1 and 1 2. Numerical values in the figures represent mm sizes.

On the substrate, a cream solder (M705-GRN360-K2-V, solder alloy: Sn-Ag-Cu, melting point of the alloy: 219 ° C, manufactured by Senju Metal Industries, Tokyo, Japan) was placed, and a test piece having a metal terminal was mounted. It was fixed by reflow soldering using an infrared reflow soldering machine (SAI-260M, manufactured by Senju Metal Industries, Ltd., Tokyo, Japan). The reflow soldering cycle included 70 seconds at a temperature in the range 200-260 ° C. and 40 seconds at a temperature in the range 230-260 ° C. (peak temperature was 260 ° C.). Two reflow soldering cycles were performed. Thereafter, the substrate having the test piece was cooled to room temperature.

The test piece mounted on the substrate was broken with a nipper or a plier to remove the LCP composition from the metal end. The metal ends were then visually observed to see if flux migration occurred. Of the 20 specimens, the number of specimens in which flux migration was observed was counted. The ratio of the test piece which has flux migration is shown in Table 2.

Warp Progress Test

Connector specimens having the shapes and sizes shown in FIGS. 2 1 and 2 2 were prepared under the same conditions as above. Numerical values in FIG. 2 represent mm size.

The connector test piece obtained on the substrate was soldered using the same cream solder under the same reflow soldering conditions as above. After completion of the two cycle reflow soldering, the substrate with the connector was cooled to room temperature. Thereafter, the height of the four corners of the connector test piece was measured by a measuring instrument (QVH250pro, manufactured by Mitsutoyo, Kanagawa, Japan) to determine the flatness of the test piece. The results are shown in Table 2.

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

As is apparent from the results shown in Table 2, an electronic component made of an LCP composition comprising a glass fiber having a 6 μm number average diameter and a 100-200 μm number average length, and having a DTUL of 280-360 ° C., has a The soldering process does not cause flux migration but only small warpage.

1 Perspective view of a test piece with embedded metal ends used for flux migration testing. A represents the resin component of a test piece, and B represents the metal terminal inserted in the resin component.

The exact size of the test piece of FIG. Numerical values in the figures represent mm sizes.

2 1 Perspective view of a connector test piece used for flexural progression testing.

2 2 shows the exact size of the connector test piece of FIG. Numerical values in the figures represent mm sizes.

Claims (12)

A surface mount electronic component obtained by molding a liquid crystal polymer composition comprising the surface mount electronic component having a deformation temperature under load (DTUL) of 280-360 ° C .: 100 parts by weight of the wholly aromatic liquid crystal polymer having a crystal melting temperature of 310-410 ℃, and 5-100 parts by weight of glass fibers having a number average diameter of 4-8 μm and a number average length of 100-200 μm. The electronic component of claim 1, wherein the wholly aromatic liquid crystal polymer comprises 4-oxybenzoyl and / or 6-oxy-naphthoyl repeating units. The electronic component according to claim 2, wherein the total amount of 4-oxybenzoyl and 6-oxy-naphthoyl repeating units in the liquid crystal polymer is 50-80 mol% based on the total repeating units. The electronic component according to claim 3, wherein the liquid crystal polymer is composed of repeating units represented by formulas [1]-[4]:

[Wherein p, q, r and s represent the molar ratio (mol%) of each of the repeating units (I)-(IV) in the polymer and satisfy the following formula: 60≤p + q≤78 0.05≤q≤3 11≤r≤20 11≤s≤20 p + q + r + s = 100]. The electronic component of claim 1 soldered with lead-free solder having a melting point of 200-250 ° C. at the surface of the substrate. The electronic component according to any one of claims 1 to 5, wherein the 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. A liquid crystal polymer composition for preparing a surface mount electronic component, comprising: a liquid crystal polymer composition having a deformation temperature under load (DTUL) of 280-360 ° C .: 100 parts by weight of the wholly aromatic liquid crystal polymer having a crystal melting temperature of 310-410 ℃, and 5-100 parts by weight of glass fibers having a number average diameter of 4-8 μm and a number average length of 100-200 μm. 8. The composition of claim 7, wherein the wholly aromatic liquid crystalline polymer comprises 4-oxybenzoyl and / or 6-oxy-naphthoyl repeat units. The composition of claim 8 wherein the total amount of 4-oxybenzoyl and 6-oxy-naphthoyl repeat units in the polymer is 50-80 mole percent, based on the total repeat units. The composition according to claim 9, wherein the liquid crystal polymer is composed of repeating units represented by formulas [1]-[4]:

[Wherein p, q, r and s represent the molar ratio (mol%) of each of the repeating units (I)-(IV) in the polymer and satisfy the following formula: 60≤p + q≤78 0.05≤q≤3 11≤r≤20 11≤s≤20 p + q + r + s = 100]. A method of mounting an electronic component on a circuit board according to claim 1, comprising the step of soldering the component onto the surface of the substrate using a cream solder comprising solder alloy and flux. 12. The method of claim 11, wherein the solder alloy is a lead free solder alloy having a melting point of 200-250 ° C.

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