JP5196430B2 - Circuit forming component and manufacturing method thereof - Google Patents

Description

  The present invention relates to a circuit-forming component having a hollow three-dimensional shape such as a cylinder and a method for manufacturing the same.

  A method of manufacturing a three-dimensional circuit board by forming a circuit on the inner periphery of a three-dimensional insulating substrate such as a cylinder or a sphere has been studied. For example, a conductive circuit is formed on the surface of a molded body that is formed into a spherical shape with a low-melting-point metal such as tin or solder, and this molded body is loaded in a state where a space is maintained on the inner periphery of the mold, The thermosetting resin is filled and cured, and the thermosetting resin molded body composed of the molded body and the thermosetting resin cured body on the outer periphery thereof is taken out of the mold, and the low melting point metal molded body is melted and removed. Thus, a method of manufacturing a three-dimensional circuit board formed by transferring a conductive circuit to the inner periphery of a spherical thermosetting resin cured body has been proposed (see Patent Document 1).

  In Patent Document 1, when a conductive circuit is formed on the surface of a spherical molded body, a resist film is provided on the surface of the molded body, exposed using a photomask and developed, and the resist film corresponding to the circuit pattern is developed. Is removed, and then a conductive material is attached to the removed portion of the resist film. However, when forming a conductive circuit through a patterning process using such a photomask, there are problems in productivity due to increased man-hours and high accuracy on the surface of a three-dimensional solid shape such as a cylindrical shape or a spherical shape. It is difficult to expose and pattern, and there is a problem that it is difficult to form a conductive circuit with high accuracy.

On the other hand, in order to solve such a problem of Patent Document 1, it has been proposed to form a circuit on the inner surface of a three-dimensional insulating substrate such as a cylinder by a patterning method using an electromagnetic wave such as a laser (patent) Reference 2). In this method, a conductive layer is formed on the surface of a transfer molding, an electromagnetic wave such as a laser is irradiated to form a circuit, an insulating substrate is molded outside the circuit formed, and then the transfer substrate is removed. By removing the transfer substrate while leaving a circuit on the insulating substrate, a circuit can be formed on the inner periphery of a three-dimensional insulating substrate such as a cylinder.
JP-A-9-148712 JP 2006-49574 A

  However, in the technique described in Patent Document 2, when a polylactic acid resin as described in the examples is used as a transfer resin, it is difficult to dissolve in an alkaline aqueous solution. For this reason, polyethylene glycol is used in an amount of about 10%. However, in the circuit formation process, particularly in the wet plating process, a part of the transfer resin melts in the specific plating process, and the plating is contaminated. There is.

  In addition, when a liquid crystalline polymer with high heat resistance and good resin flow is used for the insulating substrate, the liquid crystalline polymer has a high solidification speed, low adhesion to the conductive circuit, and the circuit peels off without being transferred. There are problems such as.

  The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide a method for easily and reliably forming a circuit on the inner periphery of a three-dimensional insulating substrate such as a cylinder.

  That is, the present invention uses a molded article obtained by coating the surface of a polyglycolic acid-based resin molded article and forming a circuit as an insert material, insert molding with a liquid crystalline polymer to which an epoxy resin is added, and converting the metallic circuit into a liquid crystalline polymer. After the transfer, the method for producing a circuit forming component is characterized in that the polyglycolic acid resin is removed.

  According to the present invention, it is possible to easily and reliably form a circuit on the inner periphery of a three-dimensional insulating base material such as a cylinder. The circuit forming component of the present invention can be used as a component such as a micro actuator, a micro electrostatic encoder, a micro electrostatic motor, or a micro pump.

  Hereinafter, the present invention will be described in detail.

  The polyglycolic acid resin used in the present invention is a glycolic acid homopolymer consisting only of glycolic acid repeating units represented by the following general formula (3), that is, polyglycolic acid (a bimolecular cyclic ester of glycolic acid). And a glycolic acid copolymer containing 60% by weight or more of the above-mentioned glycolic acid repeating unit.

  Examples of the comonomer that gives a glycolic acid copolymer together with the glycolic acid monomer of glycolide include ethylene oxalate (that is, 1,4-dioxane-2,3-dione), lactides, and lactones (for example, β-pro Piolactone, β-butyrolactone, β-piparolactone, γ-butyrolactone, δ-valerolactone, β-methyl-δ-valerolactone, ε-caprolactone, etc.), carbonates (eg, trimethylene carbonate, etc.), ethers (eg, , 1,3-dioxane, etc.), cyclic esters such as ether esters (eg, dioxanone), amides (eg, ε-caprolactam, etc.); lactic acid, 3-hydroxypropanoic acid, 3-hydroxybutanoic acid, 4- Hydroxy, such as hydroxybutanoic acid and 6-hydroxycaproic acid A carboxylic acid or an alkyl ester thereof; a substantially equimolar mixture of an aliphatic diol such as ethylene glycol or 1,4-butanediol and an aliphatic dicarboxylic acid such as succinic acid or adipic acid or an alkyl ester thereof; Or 2 or more types of these can be mentioned. These comonomers can be used as a starting material for giving a glycolic acid copolymer together with the glycolic acid monomer of glycolide.

  The polyglycolic acid resin preferably has a molecular weight (Mw in terms of polymethyl methacrylate (weight average molecular weight)) in the range of 1,000 to 500,000 in GPC measurement using a hexafluoroisopropanol solvent. If the molecular weight is too high, it becomes difficult to remove at the time of manufacturing the circuit-forming component in the present invention, and if the molecular weight is too low, molding becomes difficult, so an appropriate molecular weight needs to be selected.

  In the present invention, inorganic and organic additives, other decomposable resins and water-soluble resins can be added for the purpose of improving moldability, decomposability, crystallinity and the like.

  The polyglycolic acid resin molded product used in the present invention preferably has a surface crystallinity of 5% or more. The polyglycolic acid resin is a resin that can be either crystalline or amorphous depending on the molding conditions. If the surface of the polyglycolic acid resin molded product is amorphous, there will be cracks in the metal film formed on it. May enter. When the crystallinity of the surface of the polyglycolic acid resin molded product is 5% or more, a stable and good metal film free from cracks can be obtained.

  In order to set the crystallinity of the surface of the polyglycolic acid resin molded article to 5% or more, a method of crystallizing in the mold at the time of injection molding can be used. For example, the injection molding conditions of the polyglycolic acid resin molded product can be set to relatively high temperature conditions, a resin temperature of 230 to 270 ° C., and a mold temperature of 80 to 130 ° C.

  Moreover, even if it is a molded product injection-molded at a temperature lower than the above-mentioned injection molding conditions, by performing a heat treatment at 100 to 130 ° C. for 20 seconds to 1 hour after molding, the surface crystallinity is 5% or more. Can be achieved. As a heat treatment method, an oven, a hot stove, or the like can be used. Of course, the heat treatment may be applied to a molded product injection-molded under the injection molding conditions.

  Next, metal coating is performed on the surface of the polyglycolic acid resin. As the metal coating method, one or more methods selected from conventional electroplating, chemical plating, ion plating, sputtering and vapor deposition can be combined.

  Next, a circuit is formed on the polyglycolic acid resin molded product whose surface is metal-coated by an appropriate method such as exposure, laser, or cutting.

  Next, the molded product formed with the circuit is used as an insert material, and insert molding is performed with a liquid crystalline polymer to which an epoxy resin is added.

  The liquid crystalline polymer used in the present invention refers to a melt processable polymer having a property capable of forming an optically anisotropic molten phase. The property of the anisotropic molten phase can be confirmed by a conventional polarization inspection method using an orthogonal polarizer. More specifically, the anisotropic molten phase can be confirmed by using a Leitz polarizing microscope and observing a molten sample placed on a Leitz hot stage under a nitrogen atmosphere at a magnification of 40 times. When the liquid crystalline polymer applicable to the present invention is inspected between crossed polarizers, the polarized light is normally transmitted even in the molten stationary state, and optically anisotropic.

  The liquid crystalline polymer as described above is not particularly limited, but is preferably an aromatic polyester or an aromatic polyester amide, and a polyester partially containing an aromatic polyester or an aromatic polyester amide in the same molecular chain. It is in. They preferably have a logarithmic viscosity (IV) of at least about 2.0 dl / g, more preferably 2.0-10.0 dl / g when dissolved in pentafluorophenol at 60 ° C. at a concentration of 0.1% by weight. .) Are used.

  The aromatic polyester or aromatic polyester amide as the liquid crystalline polymer applicable to the present invention is particularly preferably at least one compound selected from the group of aromatic hydroxycarboxylic acids, aromatic hydroxyamines, and aromatic diamines. Aromatic polyesters and aromatic polyester amides as constituent components.

More specifically,
(1) A polyester mainly composed of one or more aromatic hydroxycarboxylic acids and derivatives thereof;
(2) mainly (a) one or more of aromatic hydroxycarboxylic acids and derivatives thereof; and (b) one or more of aromatic dicarboxylic acids, alicyclic dicarboxylic acids and derivatives thereof; c) Polyester comprising at least one or more of aromatic diol, alicyclic diol, aliphatic diol and derivatives thereof;
(3) mainly (a) one or more aromatic hydroxycarboxylic acids and derivatives thereof; (b) one or more aromatic hydroxyamines, aromatic diamines and derivatives thereof; and (c). A polyesteramide comprising one or more of aromatic dicarboxylic acid, alicyclic dicarboxylic acid and derivatives thereof;
(4) mainly (a) one or more aromatic hydroxycarboxylic acids and derivatives thereof; (b) one or more aromatic hydroxyamines, aromatic diamines and derivatives thereof; and (c). One or more of aromatic dicarboxylic acid, alicyclic dicarboxylic acid and derivatives thereof; and (d) at least one or more of aromatic diol, alicyclic diol, aliphatic diol and derivatives thereof, and The polyesteramide which consists of, etc. are mentioned. Furthermore, you may use a molecular weight modifier together with said structural component as needed.

  Preferable examples of specific compounds constituting the liquid crystalline polymer applicable to the present invention include p-hydroxybenzoic acid, aromatic hydroxycarboxylic acids such as 6-hydroxy-2-naphthoic acid, 2,6-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 4,4′-dihydroxybiphenyl, hydroquinone, resorcin, aromatic diols such as compounds represented by the following general formula (I) and the following general formula (II); terephthalic acid, isophthalic acid, 4 , 4′-diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid and aromatic dicarboxylic acids such as compounds represented by the following general formula (III); aromatic amines such as p-aminophenol and p-phenylenediamine Can be mentioned.

(However, X: alkylene (C1 -C4), alkylidene, -O-, -SO -, - SO 2 -, -S -, - CO- than group _{selected, Y :-( CH 2) n -} (n = 1~4), - O (CH 2) n O- (n = 1~4) from the group selected)
Particularly preferred liquid crystalline polymers to which the present invention is applied are aromatic polyesters containing p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid as main structural unit components.

  As the liquid crystalline polymer, it is preferable to use a polymer having a melting point of 330 ° C. or lower. If a liquid crystalline polymer with a melting point exceeding 330 ° C is used, the resin temperature during molding must be 340 ° C or higher, the added epoxy resin will decompose, and gas generation will rapidly increase during molding, May interfere with the adhesion. When a liquid crystalline polymer having a melting point of 330 ° C. or lower is used, a stable adhesion between the liquid crystalline polymer and the metal film can be obtained. The melting point was measured with a differential scanning calorimeter (DSC7 manufactured by Perkin Elmer Co., Ltd.) under a temperature rising condition of 20 ° C./min.

As an epoxy resin added to a liquid crystalline polymer, what is represented by the said General formula (1) or (2) is preferable. Such an epoxy resin has good dispersibility with the liquid crystalline polymer and can obtain a stable adhesion to the metal film. In the general formulas (1) and (2), examples of the alkylidene group having 1 to 3 carbon atoms represented by R include groups such as methylene, ethylidene, and 2,2′-propylidene, and R ₁ and R Examples of the alkyl group having 1 to 5 carbon atoms represented by ₂ include groups such as methyl, ethyl, propyl, and butyl.

  N is a real number of 0.1 to 30, preferably 1 to 15. X represents a hydrogen atom or a glycidyl group, and 20 to 100% of X must be a glycidyl group, and particularly preferably 25 to 100% is a glycidyl group. Here, the real number represented by n and the ratio of the glycidyl group in X (hereinafter referred to as re-epoxidation rate) both represent average values. When n is less than 0.1 or when the glycidyl group ratio of X is less than 20%, the content of the trifunctional or higher polyfunctional epoxy compound is decreased, which is not preferable. When n exceeds 30, the viscosity becomes high, and workability deteriorates, which is not preferable.

  In the epoxy resin represented by the general formula (1), preferable are those in which R is a methylene group or 2,2′-propylidene group, p and q are both 0, and n is a real number of 1 to 15. It is.

  In the epoxy resin represented by the general formula (2), preferred are those in which r and s are both 0 and n is a real number of 1 to 15.

  Although the epoxy resin represented by the general formula (1) or (2) used in the present invention is not limited by the production method, for example, it is represented by the following general formula (4) or (5). It can be produced by polymerizing a general-purpose bisphenol-based epoxy resin and epichlorohydrin.

_{(Wherein, n, R, R 1,} R 2, p, q, r and s, _n in the general formula (1) and _{(2), R, R 1} , R 2, p, q, r And s.)
In the present invention, the addition amount of the epoxy resin is important. If the amount is small, sufficient adhesion between the liquid crystalline polymer and the metal circuit cannot be obtained, and the metal circuit is removed from the liquid crystalline polymer when the polyglycolic acid resin is removed. The problem of peeling occurs. On the other hand, if the amount is too large, gas generation at the time of molding increases, which causes a problem of inhibiting the adhesion between the liquid crystalline polymer and the metal circuit. Therefore, the addition amount of the epoxy resin is 1 to 10 parts by weight with respect to 100 parts by weight of the liquid crystalline polymer.

  Moreover, various well-known fibrous, granular, and plate-like inorganic fillers can be blended with the liquid crystalline polymer according to the purpose of use. Examples of fibrous fillers include inorganic fibrous materials such as glass fibers, carbon fibers, carbon nanotubes, and potassium titanate fibers, and granular fillers include carbon black, fullerene, graphite, silica, quartz powder, glass beads, Milled glass fiber, glass balloon, glass powder, talc, wollastonite such as oxalate, titanium oxide, zinc oxide, metal oxide such as alumina, calcium carbonate, magnesium carbonate such as magnesium carbonate, calcium sulfate, Examples thereof include metal sulfates such as barium sulfate, and examples of the plate-like filler include mica, glass flakes and various metal foils.

  These inorganic fillers can be used alone or in combination of two or more.

  As described above, the molded product with the circuit formed is used as an insert material, insert molding is performed with a liquid crystalline polymer to which an epoxy resin is added, the metal circuit is transferred to the liquid crystalline polymer, and then the polyglycolic acid resin is removed. . Thereby, the circuit formation component which formed the circuit in the inner periphery of the insulating base material is completed.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

The materials and molding methods used in the following examples are as follows.
-Polyglycolic acid-based resin In a sealable container, 355 kg of glycolide (manufactured by Kureha Co., Ltd., impurity content: glycolic acid 30 ppm, glycolic acid dimer 230 ppm, moisture 42 ppm) is added, and the container is The mixture was sealed, and steam was circulated through the jacket while stirring, and the contents were melted by heating to 100 ° C. to obtain a uniform solution. To this solution, 10.7 g of tin dichloride dihydrate and 1220 g of 1-dodecyl alcohol were added with stirring.

  While maintaining the temperature of the contents at 100 ° C., the contents were transferred to a polymerization apparatus having a plurality of metal (SUS304) tubes having an inner diameter of 24 mm. This apparatus is composed of a main body portion on which a pipe is installed and an upper plate, and both the main body portion and the upper plate have a jacket structure, and heat medium oil is circulated through the jacket portion. As soon as the contents were transferred into each tube, an upper plate was attached.

  A heat medium oil of 170 ° C. was circulated through the main body portion and the jacket portion of the upper plate and held for 7 hours. After 7 hours, the heat transfer oil was cooled to room temperature, and then the upper plate was removed, and the body part was rotated in the vertical direction to take out the mass of the produced polyglycolic acid. This lump was pulverized by a pulverizer and dried overnight at 120 ° C. to obtain a polyglycolic acid pulverized product.

  In this polyglycolic acid pulverized product, an approximately equimolar mixture of mono- and di-stearyl acid phosphates (“ADEKA STAB AX-71” manufactured by ADEKA Co., Ltd.) at a ratio of 300 ppm with respect to the pulverized polyglycolic acid product. The product added and mixed in was extruded using a twin screw extruder to obtain polyglycolic acid resin pellets. The obtained polyglycolic acid resin pellets were heat-treated at 200 ° C. for 9 hours in a dryer in a nitrogen atmosphere.

The polyglycolic acid resin thus obtained was used in the following examples.
・ Liquid crystal polymer with epoxy resin added 5 parts by weight of the following epoxy resin and 25 parts by weight of glass fiber are added to 100 parts by weight of liquid crystal polymer (Polyplastics Vectra C950; melting point 325 ° C.) and biaxial extrusion is performed. Using a machine (Tex30α type, manufactured by Nippon Steel Works, Ltd.), kneaded at 330 ° C. and pelletized.
(Epoxy resin)
In a flask equipped with a reflux apparatus, a stirring apparatus, a decompression apparatus, and a dropping apparatus, a bisphenol A-based epoxy resin (in the general formula (4), n = 2.1, p = q = 0, R is 2,2 ′ -Propyridene group) 47.5 parts by weight, epichlorohydrin 95 parts by weight and tetramethylammonium chloride 0.2 parts by weight were charged, and 9.5 parts by weight of sodium hydroxide was added as a 48% by weight aqueous solution in the dropping apparatus. deep. This aqueous sodium hydroxide solution was added dropwise at 80 torr at an internal temperature of 50 to 60 ° C. over 2 hours under reflux, and at the same time, water was removed by azeotropic distillation. Thereafter, the mixture was further reacted for 2 hours, cooled, filtered, and the solvent was removed by evaporation to obtain the desired epoxy resin (re-epoxidation rate = 87%, softening point 40 ° C.).
[Manufacture of circuit forming parts]
In the following, circuit-formed components were manufactured according to the procedure shown in FIG.

  First, as shown in FIG. 1 (a), a cylindrical molded article having a three-dimensional solid surface on the outer surface is made from a polyglycolic acid resin using an injection molding machine at a resin temperature of 260 ° C. and a mold temperature of 120 ° C. Molded. The crystallinity of the surface of the obtained polyglycolic acid resin molded product was 5% or more (about 15%).

The crystallinity was measured as follows.
(Crystallinity measurement method)
The surface of the polyglycolic acid resin molded product was cut into a test piece. A specific gravity solution was prepared using carbon tetrachloride and 1,2-dichloroethane, and the density D of the test piece at 23 ° C. was measured by a density gradient piping method. From the obtained density D, polyglycolic acid crystal density D1 = 1.69 g / cm ³ , and amorphous density D2 = 1.51 g / cm ³ , the degree of crystallinity (%) was calculated by the following formula.

Crystallinity (%) = (D−D2) / (D1−D2) × 100
Next, as shown in FIG. 1B, a metal film 2 was formed on the outer peripheral surface of the polyglycolic acid resin molded product 1. The metal film 2 was formed by a DVD method such as sputtering. Copper as a metal was formed to a thickness of submicron.

  After forming the metal film 2 on the outer peripheral surface of the polyglycolic acid resin molded article 1 as described above, the metal film 2 was irradiated with electromagnetic waves from the outside. As the electromagnetic wave, a laser such as YAG-SHG having a wavelength of 532 nm or YAG-THG having a wavelength of 355 nm can be used. By irradiating the metal film 2 with electromagnetic waves in this way, as shown in FIG. 1 (c), the portion of the metal irradiated with the electromagnetic waves can be removed and a circuit pattern can be formed. The electromagnetic wave scans along the outer shape of the edge forming the circuit pattern, electrically cuts the circuit portion and the non-circuit portion, and energizes the circuit portion by electroplating to form a thick metal film (FIG. 1 (d )reference). Thereafter, a metal film having a thickness of submicron was removed (light etching) to form a circuit.

  After forming a circuit with a circuit pattern on the outer surface of the polyglycolic acid resin molded article 1 in this way, as shown in FIG. 1 (e), an epoxy is formed on the outer surface of the polyglycolic acid resin molded article 1 over the entire circumference. The liquid crystalline polymer 3 to which the resin was added was molded and laminated. Molding of the liquid crystalline polymer 3 to which the epoxy resin is added is performed by setting the polyglycolic acid resin molded product 1 in the mold as an insert material, and the gap between the inner periphery of the mold and the outer periphery of the polyglycolic acid resin molded product 1 It was performed by insert molding in which the resin was filled.

  As described above, the circuit can be transferred to the liquid crystalline polymer by molding the liquid crystalline polymer to which the epoxy resin is added.

  Thereafter, by removing the polyglycolic acid resin molded product 1 from the inside of the liquid crystalline polymer 3, as shown in FIG. 1 (f), the inner circumference of the liquid crystalline polymer 3 from the polyglycolic acid resin molded product 1 is obtained. The circuit forming component 4 in which the circuit was formed by being transferred to was obtained.

  The removal of the polyglycolic acid-based resin molded article 1 was performed by immersing the circuit-forming component 4 in a 5% aqueous sodium hydroxide solution at 80 ° C. and removing it by dissolution. In this case, the polyglycolic acid resin molded product could be completely removed in 60 minutes. Incidentally, when the circuit forming component 4 was obtained in the same manner as in the above example except that a polylactic acid resin was used instead of the polyglycolic acid resin, it was immersed in a 5% sodium hydroxide aqueous solution at 80 ° C. for 5 hours. Even so, the polylactic acid resin could not be dissolved and removed.

Each process of an example of embodiment of this invention is shown, (a) thru | or (f) is side sectional drawing, respectively.

Explanation of symbols

1 Polyglycolic acid resin molded product 2 Metal film 3 Liquid crystalline polymer 4 Circuit forming component

Claims (8)

After using a molded product with a metal coating on the surface of a polyglycolic acid resin molded product and forming a circuit as an insert material, insert molding with a liquid crystalline polymer to which an epoxy resin has been added and transferring the metal circuit to the liquid crystalline polymer, A method for producing a circuit-forming component, comprising removing a polyglycolic acid-based resin ,
The polyglycolic acid-based resin includes a glycolic acid homopolymer composed of a glycolic acid repeating unit represented by the following repeating unit (3):

The polyglycolic acid resin molded product has a surface crystallinity of 5% or more,
A method for producing a circuit-forming component, wherein the epoxy resin is represented by the following general formula (1) or (2).

(In the formula, n is a real number of 0.1 to 30, and R is a single bond or an alkylidene group having 1 to 3 carbon atoms.
R ₁ and R ₂ are each independently an alkyl group having 1 to 5 carbon atoms, p and q are independently 0 or an integer of 1 to 4, and r and s are independently 0 or It is an integer of 1-3. X represents a hydrogen atom or a glycidyl group, but 20% or more of X is a glycidyl group. ) The method for producing a circuit forming component according to claim 1, wherein the liquid crystalline polymer to which the epoxy resin is added contains 1 to 10 parts by weight of the epoxy resin with respect to 100 parts by weight of the liquid crystal polymer .   The method for producing a circuit-forming component according to claim 1 or 2, wherein the injection molding conditions of the polyglycolic acid resin molded product are a resin temperature of 230 to 270 ° C and a mold temperature of 80 to 130 ° C.   The method for producing a circuit-formed component according to any one of claims 1 to 3, wherein the polyglycolic acid-based resin molded product is heat-treated at 100 to 130 ° C for 20 seconds to 1 hour.   The method for producing a circuit-forming component according to any one of claims 1 to 4, wherein the polyglycolic acid-based resin is decomposed and removed with an alkaline aqueous solution or high-temperature steam.   The method for producing a circuit forming component according to any one of claims 1 to 5, wherein the metal coating is performed by one or more methods selected from electroplating, chemical plating, ion plating, sputtering and vapor deposition.   The method for producing a circuit-forming component according to any one of claims 1 to 6, wherein a liquid crystalline polymer having a melting point of 330 ° C or lower is used. Circuit formed parts produced in any one of claims method according to claim 1-7.

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