JP2006117984A - Plating polyester resin molded product and manufacturing method thereof - Google Patents

Abstract

[PROBLEMS] To provide a plated synthetic resin molded article excellent in surface smoothness and adhesion strength of a plating layer, having high heat resistance, flame retardant as required, and remarkably excellent material strength. Provide a method.
A plated polyester resin molded product having a plating layer 2 formed on the surface of a polyester resin molded product 1 and subjected to irradiation crosslinking, having a bending strength measured in accordance with ISO 178 of 110 MPa or more and an arithmetic average roughness of the plated layer surface. The rate of dimensional change measured under conditions where Ra is 1 μm or less, the adhesion strength between the resin molded product and the plating layer is 2 MPa or more, and the zone set at 260 ° C. of the reflow furnace is passed for 60 seconds. A plated polyester resin molded product, both of which are 1% or less, and a method for producing the same.
[Selection] Figure 1

Description

  The present invention relates to a plated polyester resin molded article (Plated-Polyester Article) and a method for producing the same. More specifically, the present invention has high strength and high heat resistance, and is excellent in surface smoothness and adhesion of a plating layer, and is necessary. The present invention relates to a plated polyester resin molded product that can be highly flame retardant according to the method and a method for producing the same.

  In the field of electronics mounting technology, semiconductors and functional parts are placed on a circuit board and connected together with other components, using film formation technology, micro-connection technology, and sealing technology. It is three-dimensionally integrated into an electronic device with the required performance. Various mounting methods have been developed for semiconductor chip packages such as IC and LSI.

  Inside the semiconductor package, a wire bonding method has been developed in which an electrode formed on a semiconductor chip and an inner lead of an external wiring are electrically connected by a bonding wire and sealed with epoxy resin or ceramics. In recent years, the degree of integration of semiconductor chips has improved year by year, and the number of terminals has increased accordingly. Therefore, in order to reduce the size of the package and mount it at a high density, an area array terminal type package such as BGA (Ball Grid Array) to which a multilayer printed wiring board technology is applied has been developed.

  Furthermore, recently, in addition to downsizing, weight reduction, and high functionality of electronic devices, there is an increasing demand for rationalization of wiring such as rationalization of devices, space saving, and improvement of assembly. In response to such a requirement for wiring rationalization, a three-dimensional injection molded circuit component (Molded Interconnect Device; hereinafter abbreviated as “MID”) in which wiring is three-dimensionally formed on the surface of an injection molded product has been developed. Unlike printed wiring boards, MID uses a plating film (plating layer) to form a circuit instead of copper foil.

  To manufacture MID, a plating grade resin is used for injection molding. After the entire surface of the obtained molded product is roughened (etched), a plating catalyst is applied to form a plating film. The plating film is generally formed by electroless plating or electroless plating and electroplating thereon. Next, a circuit is formed using a resist. As the circuit forming method, for example, there are a subtractive method using an etching resist and a semi-additive method using a plating resist.

  As another manufacturing method of MID, after forming an easily plateable resin to form a molded article for a three-dimensional circuit, a catalyst is applied. Next, a difficult-to-platable resin is molded into a plating-free portion of the easily-platable resin molded product to produce an integrated molded product. Finally, plating is performed by a full additive method to form a circuit. The molded difficult-to-plate resin serves as a plating resist during plating.

  As described above, MID is obtained by forming a circuit on the surface of a molded article of a thermoplastic resin or a thermosetting resin using a wet plating process such as electroless plating or electroplating. The MID is a wiring board having both a function as a structural member and a functional component and a function as a wiring member. Since the resin molded product is manufactured by a melt molding method such as an injection molding method, the shape can be freely designed, and the productivity is excellent. Moreover, since the plating layer can be formed on an arbitrary surface of the resin molded product, a circuit can be formed three-dimensionally, which is convenient for use as a semiconductor chip package.

  MID is not only used as a package for semiconductor chips, but it is also possible to integrate peripheral circuit components and mechanical components into one component, which enables a compact and rational mounting design. There is also. Therefore, applications of MID are being developed in a wide range of fields such as electronic device component package cases, wiring rationalization products, and hybrid IC adapters.

  Since MID is often used in a limited space of electronic equipment, it tends to be smaller and thinner. Further, the plating circuit portion of the MID is electrically connected to the semiconductor package by wire bonding, and surface mount components are mounted by reflow furnace soldering.

  Therefore, MID is required to have high material strength that can cope with downsizing and thinning, smoothness and adhesion strength of the plating layer that allows strong wire bonding, and heat resistance that can withstand reflow soldering mounting. It has been.

  Specifically, regarding the material strength, in many cases, it is required that the material has a strength that prevents at least a portion having a thickness of 0.4 mm from cracking. This strength corresponds to the case where the bending strength measured according to IS0178 is 110 MPa or more. About the smoothness of a plating layer, it is desirable that the surface roughness of a plating layer is 1 micrometer or less in arithmetic mean roughness Ra from a viewpoint of the connection reliability by wire bonding. As for plating adhesion, when a value of 2 MPa or more is shown by the measurement method described later, it can be evaluated that the connection reliability is good. Regarding heat resistance, considering that surface mounting of lead-free solder is becoming mainstream, high heat resistance that does not deform at a temperature of 260 ° C. is required. That is, an injection-molded plate of length 30 × width 10 × thickness 0.4 mm is passed through a zone set at 260 ° C. in a reflow furnace in 60 seconds, and the dimensional change rate in both the longitudinal direction and the width direction is 1% or less. If so, it can be evaluated that the reflow resistance is good.

  In order to achieve both material strength and heat resistance, a super engineering plastic represented by a liquid crystal polymer (LCP) is used. However, since LCP has a poor dispersion state of the inorganic filler, variation in surface roughness increases when etched. The surface roughness after plating reflects the surface roughness during etching before plating. When the surface of the LCP molded product is etched so that the surface roughness Ra of the plating layer is 1 μm or less, a portion having an adhesion strength of 2 MPa or less is generated, and conversely, an etching is performed so that a portion having an adhesion strength of 2 MPa or less is not generated. A portion having a surface roughness of 1 μm or more is generated (see Comparative Examples 1 and 2 below).

  The present inventors have proposed a plated polyester resin molded product in which a plating layer is formed on the surface of a polyester resin molded product, and the polyester resin molded product is crosslinked by irradiation with ionizing radiation (Patent Document 1). Specifically, a resin composition in which an inorganic filler having an average particle diameter of 1 to 10 μm is dispersed in a polyester resin that can be cross-linked by irradiation with ionizing radiation is melt-molded to produce a resin molded product, and a plating layer is formed on the surface thereof. It is a plated polyester resin molded product formed and cross-linked by irradiating the polyester resin with ionizing radiation. This plated polyester resin molded product can reduce the arithmetic average roughness Ra of the plating layer, and can further increase the adhesion strength of the plating layer.

  However, according to the method disclosed in Patent Document 1, 5 parts by weight of glycidyl methacrylate, 3 parts by weight of triallyl isocyanurate, and 45 parts by weight of calcium pyrophosphate (average particle size: 6 μm) with respect to 100 parts by weight of polybutylene terephthalate (PBT) Part and 0.1 part by weight of antioxidant were melt-mixed with a biaxial mixer, and a resin molded product of 80 mm × 10 mm × 4 mm was prepared by injection molding, and a sample for bending test was prepared by irradiation with 250 kGy electron beam. However, it was found that the bending strength of this sample measured according to IS0178 was as low as 84 MPa (see Comparative Example 3 described later).

  As a method for improving the bending strength of a resin molded product, a method using a fibrous reinforcing filler having a high aspect ratio is known. For example, a method of plating a thermoplastic polyester resin injection molded product blended with an inorganic filler having a high aspect ratio such as calcium silicate has been proposed (Patent Document 2). Therefore, with respect to 100 parts by weight of polybutylene terephthalate (PBT), 5 parts by weight of glycidyl methacrylate, 3 parts by weight of triallyl isocyanurate, 43 parts by weight of calcium silicate (average fiber diameter 3 μm, aspect ratio 10), and antioxidant 0.1 parts by weight were melt-mixed with a biaxial mixer, a molded product of 80 mm × 10 mm × 4 mm was produced by injection molding, and a sample for bending test was obtained by irradiation with 250 kGy electron beam. When the bending strength of this sample was measured according to IS0178, it was 120 MPa, and it was found that good strength was obtained. However, using the same material, a plate 30 mm long × 10 mm wide × 0.4 mm thick was injection molded, and a test sample irradiated with 250 kGy electron beam was passed through a zone set at 260 ° C. in a reflow oven in 60 seconds. When the dimensional change rate was measured, the change rate in the longitudinal direction was 2.1%, the dimensional change rate in the width direction was 1.5%, and heat resistance (reflow resistance) was insufficient. It was found (see Comparative Example 4 below).

  A method for producing a surface metallized resin molded product in which a resin composition containing glass fiber in a thermoplastic polyester resin is molded, and the surface of the obtained molded product is roughened and then subjected to plating treatment has been proposed. (Patent Document 3). However, in the method of simply blending the glass fiber with the polyester resin, it is necessary to increase the degree of roughening in order to increase the adhesion strength of the plating layer, and therefore the surface roughness of the plating layer is reduced. Conversely, when the degree of roughening is lowered, the surface roughness of the plating layer is improved, but the adhesion strength of the plating layer is reduced (see Comparative Examples 5 to 6 below).

  For the above reasons, a resin molded product having both bending strength of 110 MPa or more, plating smoothness of Ra of 1 μm or less, plating adhesion strength of 2 MPa or more, and heat resistance of 260 ° C. has not been realized, and it is manufactured. The development of materials and processes that can be performed has been desired.

  In addition, electronic devices such as home appliances and office equipment are designed to be flame retardant so that a wiring board incorporated therein does not ignite or burn. Therefore, the wiring board used in an electronic device is required to have flame retardancy. Specifically, high flame retardance satisfying strict standard values such as V-0 defined in UL standard UL94 is required as flame retardancy. Therefore, in addition to having the above-described characteristics, there is a need for a plated resin molded article suitable for MID and the like that can be highly flame-retardant as required.

International Publication No. 2004/022815 Pamphlet Japanese Patent Publication No.62-3173 Japanese Patent Publication No. 6-96769

  The purpose of the present invention is to provide a plating composition that has excellent surface strength and adhesion strength of the plating layer, has high heat resistance, and can be flame-retarded as required. It is providing the resin molded product and its manufacturing method.

  As a result of diligent research to solve the above-mentioned problems, the present inventors have found that an average fiber diameter of 0.1 to 5 μm, an aspect ratio of 5 to 100, and a pH of polyester resin that can be crosslinked by irradiation with ionizing radiation. Forming a polyester resin molded article using a resin composition in which inorganic fibers of 2 to 10 are dispersed at a specific volume ratio, forming a plating layer on the surface of the polyester resin molded article, and Before or after formation, the polyester resin is cross-linked by irradiating with ionizing radiation so that the plating layer has a surface roughness Ra of 1 μm or less, a plating adhesion strength of 2 MPa or more, and a reflow resistance of 260 ° C. In addition, it has been found that a plated polyester resin molded product having a bending strength of 110 MPa or more can be obtained. The present invention has been completed based on these findings.

According to the present invention, the plating layer (B) is formed on the surface of the polyester resin molded article (A), and the polyester resin forming the polyester resin molded article (A) is crosslinked by irradiation with ionizing radiation. A polyester resin molded article,
(A) The bending strength measured according to ISO178 is 110 MPa or more,
(B) The arithmetic average roughness Ra of the plating layer (B) surface is 1 μm or less,
(C) Dimensional change measured under conditions in which the adhesion strength between the polyester resin molded product (A) and the plating layer (B) is 2 MPa or more, and (d) a zone set at 260 ° C. in a reflow furnace is passed for 60 seconds. A plated polyester resin molded product characterized in that the rate is 1% or less in both the longitudinal direction and the width direction is provided.

According to the present invention, the plating layer (B) is formed on the surface of the polyester resin molded article (A), and the polyester resin forming the polyester resin molded article (A) is crosslinked by irradiation with ionizing radiation. A method for producing a plated polyester resin molded product, comprising:
Production of a plated polyester resin molded article in which a plating layer (B) is formed on the surface of the polyester resin molded article (A), and the polyester resin forming the polyester resin molded article (A) is crosslinked by irradiation with ionizing radiation A method,
(I) An inorganic fiber having an average fiber diameter of 0.1 to 5 μm, an aspect ratio of 5 to 100, and a pH of 2 to 10 is dispersed in a proportion of 5 to 50% by volume in a polyester resin that can be cross-linked by irradiation with ionizing radiation. Step 1 of preparing a prepared resin composition;
(II) Step 2 of melt-molding the resin composition into the shape of a polyester resin molded article (A) having a desired shape;
(III) Step 3 of forming a plating layer on the surface of the polyester resin molded product (A); and (IV) Step of irradiating the polyester resin molded product (A) with ionizing radiation before or after step 3 4;
A method for producing a plated polyester resin molded article characterized by comprising:

  According to the present invention, a plated polyester resin molded article having high strength and high heat resistance, excellent in surface smoothness and adhesion of a plating layer, and highly flame-retardant as required, and a method for producing the same Is provided. The plated polyester resin molded product of the present invention has strength corresponding to downsizing and thinning of electronic equipment, sufficient adhesion strength and a smooth plating layer that can be wire-bonded, and has heat resistance at the reflow temperature. Since it is excellent and can impart a high degree of flame retardancy as required, there is a great utility value in the field of manufacturing electronic parts such as MID used for semiconductor packages and the like.

1. In the present invention, a polyester resin that can be crosslinked by irradiation with ionizing radiation is used. Polyester resins include polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polybutylene naphthalate (PBN), polyethylene naphthalate (PEN), polycyclohexylene terephthalate (PCT), polycyclohexylene terephthalate / polyethylene terephthalate copolymer Examples thereof include a combination (PCT-PET), polycyclohexylenedimethylene terephthalate / isophthalate copolymer (PCTA), polybutylene succinate (PBS), and the like. These polyester resins can be used alone or in combination of two or more. Among these, PBT is particularly preferable.

  These polyester resins can be made into a crosslinkable polyester resin by irradiation with ionizing radiation, for example, by the following method.

(1) Method of blending polyfunctional monomer:
By blending a polyfunctional monomer into the polyester resin as described above, a polyester resin that can be cross-linked by irradiation with ionizing radiation can be obtained. Examples of multifunctional monomers include diacrylates such as diethylene glycol diacrylate; dimethacrylates such as ethylene glycol dimethacrylate and dipropylene glycol dimethacrylate; triacrylates such as trimethylolethane triacrylate and trimethylolpropane triacrylate; And trimethacrylates such as methylolethane trimethacrylate and trimethylolpropane trimethacrylate; (iso) cyanurates such as triallyl cyanurate and triallyl isocyanurate; Of these polyfunctional monomers, triallyl isocyanurate and trimethylolpropane trimethacrylate are preferred.

  The polyfunctional monomer is generally used in a proportion of 0.1 to 20 parts by weight, preferably 0.5 to 15 parts by weight, and more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the polyester resin. If the blending amount of the polyfunctional monomer is too small, the degree of crosslinking of the polyester resin may become insufficient even when irradiated with ionizing radiation. If the degree of crosslinking is insufficient, it becomes difficult to satisfy heat resistance such as reflow resistance. If the amount of the polyfunctional monomer is too large, melt mixing with the polyester resin becomes difficult, and further, burrs during molding increase, which is not preferable.

(2) Method for introducing polymerizable functional group:
By reacting the polyester resin with a polyfunctional organic compound and introducing a polymerizable functional group into the polyester resin, a polyester resin that can be crosslinked by irradiation with ionizing radiation can be obtained.

  As polyfunctional organic compounds, polymerizable functional groups such as vinyl group, allyl group, acryloyl group, methacryloyl group, amino group, hydroxyl group, epoxy group (glycidyl group), carboxylic acid group, acid anhydride in the same molecule An organic compound having a functional group such as a physical group is used.

  Examples of such polyfunctional organic compounds include glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, 2-methylallyl glycidyl ether, p-glycidyl styrene, glycidyl ether of o-, m- or p-allylphenol, 3 , 4-epoxy-1-butene, 3,4-epoxy-3-methyl-1-butene, 3,4-epoxy-1-pentene, 5,6-epoxy-1-hexene, 1,3-diallyl-5 -Glycidyl isocyanurate, 1-allyl-3,5-diglycidyl isocyanurate, crotonic acid, maleic anhydride, crotonic anhydride, undecylenic acid, β-methacryloyloxyethyl hydrogen succinate, 2-hydroxyethyl acrylate, 2- Hydroxyethyl methacrylate, 3 Hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, propylene glycol monoacrylate, propylene glycol monomethacrylate, allyl alcohol, dimethylaminoethyl methacrylate, and the like methacrylic acid tert- butylaminoethyl.

  These polyfunctional organic compounds can be used alone or in combination of two or more. Among these, glycidyl methacrylate and β-methacryloyloxyethyl hydrogen succinate are preferable. In order to react the polyester resin and the polyfunctional organic compound, it is preferable to employ a method in which both are melt mixed. In the case of melt mixing, other additive components can also be mixed together.

  The polyfunctional organic compound is generally used in a proportion of 0.1 to 20 parts by weight, preferably 0.5 to 15 parts by weight, more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the polyester resin. If the amount of the polyfunctional organic compound used is too small, the degree of crosslinking by irradiation with ionizing radiation may be insufficient. If the amount of the polyfunctional organic compound used is too large, melt mixing with the polyester resin becomes difficult, and further, burrs during molding increase, which is not preferable.

(3) Method of introducing a carbon-carbon double bond into the main chain:
In the polymerization stage of the polyester resin, it is possible to crosslink by irradiation with ionizing radiation by copolymerizing unsaturated diol and / or unsaturated dicarboxylic acid to synthesize a polyester resin having a carbon-carbon double bond in the main chain. A polyester resin can be obtained. Examples of unsaturated diols include 2-butene-1,4-diol. Examples of the unsaturated carboxylic acid include unsaturated aliphatic dicarboxylic acids such as fumaric acid, maleic acid, itaconic acid and citraconic acid, alkyl esters thereof, and acid anhydrides thereof.

  These unsaturated diols and / or unsaturated dicarboxylic acids are usually used in a proportion of 1 to 20 mol%, preferably 1 to 10 mol%, based on the diol component and / or dicarboxylic acid component. If the copolymerization ratio of the unsaturated diol and / or unsaturated dicarboxylic acid is too small, the degree of crosslinking by irradiation with ionizing radiation becomes insufficient, making it difficult to obtain sufficient heat resistance. The melting point may decrease and heat resistance may decrease. Both unsaturated diol and unsaturated dicarboxylic acid may be used in combination.

(4) Combination of the above methods:
A method combining the methods (1) to (3) can also be employed. As a preferable method, a method of combining the method (2) or (3) and the method (1) can be mentioned. For example, a preferable method is a method in which a polyfunctional monomer is added to the polyester resin having a polymerizable functional group introduced by the method (2).

2. Inorganic fibers Examples of inorganic fibers include fibers such as aluminum borate and potassium hexatitanate. It is known that aluminum borate and potassium hexatitanate are produced in the form of fibers or whiskers. Inorganic fibers include needle-like fillers such as whiskers. Among these, an aluminum borate fiber (aluminum borate whisker) is preferable from the viewpoint of the melt fluidity of the resin composition and the mechanical strength of the molded product. These inorganic fibers can be used alone or in combination of two or more.

  The average fiber diameter of the inorganic fiber used in the present invention is 0.1 to 5 μm, preferably 0.3 to 3 μm. If the average fiber diameter of the inorganic fibers is too small, the inorganic fibers tend to aggregate in the polyester resin, so that the surface roughness after etching the surface of the polyester resin molded product tends to be rough. As a result, the surface roughness Ra of the plating layer formed on the surface of the resin molded product exceeds 1 μm, and the wire bonding property is deteriorated. When the average fiber diameter of the inorganic fibers is too large, the surface roughness Ra of the plating layer exceeds 1 μm, and the wire bonding property is deteriorated.

  The aspect ratio of the inorganic fiber is 5 to 100, preferably 7 to 80. If the aspect ratio is too small, the bending strength cannot be made 110 MPa or more. If it is too large, it is easy to break during mixing with the polyester resin, and the bending strength cannot be increased to 110 MPa or more.

  The pH of the inorganic fiber is 2 to 10, preferably 4 to 8. If the pH of the inorganic fiber is too high, the heat resistance of the plated polyester resin molded product is lowered, and the dimensional change rate increases when the zone set at 260 ° C. in the reflow furnace is passed for 60 seconds. If the pH of the inorganic fiber is too low, rust is likely to occur in the plating layer. The pH of the inorganic fiber is a value measured by a method in which the inorganic fiber is dispersed in ion-exchanged water, allowed to stand for 10 minutes, filtered, and the pH of the filtrate obtained at that time is measured.

  The addition amount of the inorganic fiber is 5 to 50% by volume, preferably 10 to 30% by volume, based on the total amount of the resin composition. If the amount of inorganic fiber added is too small, the adhesion strength between the polyester resin molded product and the plating layer will decrease, and if it is too large, the surface roughness after etching the surface of the resin molded product will increase. As a result, the surface roughness Ra of the plating layer exceeds 1 μm, and the wire bonding property is deteriorated.

3. Other additives In the polyester resin composition used in the present invention, other inorganic fillers, flame retardants, colorants, lubricants, antioxidants, hydrolysis, as needed, within a range that does not impair the purpose of the present invention. Various additives such as an inhibitor and a processing stabilizer can be blended. Therefore, the plated polyester resin molded article of the present invention may contain these additives.

  When making the plated polyester resin molded product flame-retardant, a flame retardant may be blended in the resin composition during the production of the polyester resin molded product. In order to obtain a high degree of flame retardancy with a relatively small amount of addition, it is preferable to use a brominated flame retardant.

  Examples of brominated flame retardants include ethylene bistetrabromophthalimide, ethylene bispentabromodiphenyl, tetrabromophthalic anhydride, tetrabromophthalimide, tetrabromobisphenol A, tetrabromobisphenol A-bis (hydroxyethyl ether), tetrabromobisphenol. A-bis (2,3-dibromopropyl ether), tetrabromobisphenol A-bis (bromoethyl ether), tetrabromobisphenol A-bis (allyl ether), tetrabromobisphenol A carbonate oligomer, tetrabromobisphenol A epoxy oligomer, Tetrabromobisphenol S, tetrabromobisphenol S-bis (hydroxyethyl ether), tetrabromobisphenol S-bis ( , 3-dibromopropyl ether), brominated polystyrene, brominated polyphenylene ether, brominated polycarbonate, brominated epoxy resin, brominated polyester, brominated acrylic resin, brominated phenoxy resin, hexabromobenzene, pentabromoethylbenzene, decabromo Diphenyl, hexabromodiphenyl oxide, octabromodiphenyl oxide, decabromodiphenyl oxide, polypentabromobenzyl acrylate, octabromonaphthalene, hexabromocyclododecane, bis (pentabromophenyl) ethane, bis (tribromophenyl) fumarimide, N- And methyl hexabromodiphenylamine.

  These brominated flame retardants can be used alone or in combination of two or more. Among these, ethylene bistetrabromophthalimide, bis (pentabromophenyl) ethane, tetrabisphenol A carbonate oligomer, brominated polystyrene, and brominated polyphenylene ether are preferable, and ethylene bistetrabromophthalimide is a time-dependent melt viscosity during injection molding. This is particularly preferable in terms of little change.

  When blending a brominated flame retardant, it is usually used in a proportion of 5 to 50 parts by weight, preferably 10 to 45 parts by weight, particularly preferably 15 to 35 parts by weight with respect to 100 parts by weight of the polyester resin. By blending the brominated flame retardant within the above range, a high level of flame retardancy satisfying the standard value V-0 can be achieved in the UL-94 test. If the amount of the brominated flame retardant is too small, it is difficult to achieve flame retardancy that satisfies the standard value V-0 in the UL-94 test. If the amount of the brominated flame retardant is too large, defects such as burrs are likely to occur in the injection molded product.

  Along with brominated flame retardants, inorganic flame retardants or flame retardant aids such as antimony trioxide, antimony pentoxide, zinc stannate, zinc hydroxystannate, zinc borate; phosphorous flame retardants such as red phosphorus and phosphate esters A flame retardant; a chlorine-based flame retardant such as perchloropentacyclodecane; and the like can be appropriately blended as necessary.

4). Plated polyester resin molded article and method for producing the same In the present invention, a plated polyester resin molded article having a plating layer (B) formed on the surface of the polyester resin molded article (A) is obtained by the following steps (I) to (III). To manufacture.

(I) An inorganic fiber having an average fiber diameter of 0.1 to 5 μm, an aspect ratio of 5 to 100, and a pH of 2 to 10 is dispersed in a proportion of 5 to 50% by volume in a polyester resin that can be cross-linked by irradiation with ionizing radiation. Step 1 of preparing a prepared resin composition;
(II) Step 2 of melt-molding the resin composition into the shape of a polyester resin molded article (A) having a desired shape;
(III) Step 3 of forming a plating layer on the surface of the polyester resin molded product (A); and (IV) Step of irradiating the polyester resin molded product (A) with ionizing radiation before or after step 3 4.

  The method for preparing the resin composition is not particularly limited, but usually, a method of melt-mixing each component is employed. For the melt mixing, a known mixing apparatus such as an extruder type mixer such as a single screw mixer or a twin screw mixer; an intensive type mixer such as a Banbury mixer or a pressure kneader; can be used. Each component is preferably melt-mixed and pelletized using an extruder-type melt mixing apparatus. When using an extruder-type melt mixing apparatus, it is preferable to premix each component in advance using a mixer or the like.

  As a molding method of the resin composition, any melt molding method such as injection molding, extrusion molding, compression molding or the like can be adopted. However, in order to apply a plated polyester resin molded product to an electronic component such as MID. It is preferable to adopt an injection molding method.

  The shape of the polyester resin molded product (A) can be appropriately determined according to the application. You may form the layer which consists of a polyester resin molded article (A) on the surface of base materials, such as another synthetic resin molded article. Moreover, you may form and integrate a non-platable resin molded product in the pattern form on the surface of the polyester resin molded product (A).

  As a method of forming the plating layer (B) on the surface of the polyester resin molded product (A), a method of performing electroless plating according to a conventional method is preferable. As electroless plating, electroless copper plating is preferable. Specifically, the electroless copper plating on the surface of the polyester resin molded product is performed according to a conventional method: (1) pre-dip (preventing washing water from being brought into the catalyst solution), (2) tin chloride, palladium chloride, chloride It implements in each process of catalysis using the solution containing sodium etc. (catalyst), (3) accelerator, and (4) electroless copper plating.

  As the composition of the electroless copper plating, for example, a copper ion source (for example, copper sulfate), a complexing agent (for example, ETDA), a reducing agent (for example, formaldehyde), a pH adjuster (for example, NaOH), an additive ( For example, dipyridyl) is representative. A commercially available product can be used as the electroless copper plating solution.

  After the electroless plating, after washing with water, electroplating such as electrolytic copper plating can be performed. For electroplating, a method is generally employed in which a cathode and an anode are inserted into an aqueous solution in which a metal to be deposited is dissolved, a direct current is applied, and the metal is deposited on a substrate on the cathode.

  A plating layer having an appropriate thickness as a circuit may be formed only by electroless plating, but the thickness of the plating layer may be increased by using electroless plating and electroplating together. Furthermore, as a surface treatment for the contact portion (edge connector terminal) at the edge of the substrate, a surface treatment for a wire bonding pad, or a surface treatment for soldering, a nickel plating base gold plating may be performed on the copper plating layer. preferable. The nickel plating may be electroplating or electroless plating. Gold plating is performed by electroplating or electroless plating.

  Although the thickness of a plating layer can be suitably determined according to a use purpose, it is 5-50 micrometers normally, Preferably it is 8-40 micrometers, More preferably, it is 10-20 micrometers. If the thickness of the plating layer is too thin, the electric resistance of the circuit increases, which is not preferable. If the thickness of the plating layer is too thick, the plating thickness of the molded product tends to vary, and the finished product dimensions are not stable, which is not preferable.

  In the present invention, the order of the plating treatment and the crosslinking treatment by irradiation with ionizing radiation is not particularly limited. After the plating treatment, the ionizing radiation may be irradiated, or after the ionizing radiation is irradiated, the plating treatment is performed. You may go. From the viewpoint of the ease of the plating treatment process, the adhesion strength of the plating layer, and the like, it is preferable to arrange a crosslinking step by irradiation with ionizing radiation after the formation step of the plating layer.

  The polyester resin molded product (A) is crosslinked by irradiating with ionizing radiation. Examples of the ionizing radiation include electron beams (beta rays), gamma rays, alpha rays, and ultraviolet rays, but electron beams are particularly preferable from the viewpoints of easy use of the radiation source and rapid crosslinking treatment. In the case of irradiation crosslinking after forming a plating layer on the surface of the polyester resin molded product (A), it is preferable to use an accelerated electron beam or a gamma ray from the viewpoint of transmission thickness.

  The irradiation dose is preferably in the range of 50 to 1000 kGy, more preferably 100 to 800 kGy. If the irradiation dose is too low, the heat resistance (reflow resistance) of the plated polyester resin molded product becomes insufficient, and if it is too high, the polyester resin constituting the molded product may be decomposed.

  The plated polyester resin molded article of the present invention is one in which the plated layer (B) is formed on the surface of the polyester resin molded article (A), the arithmetic average roughness Ra of the plated layer (B) surface is 1 μm or less, and The adhesion strength between the polyester resin molded product (A) and the plating layer (B) is 2 MPa or more. The arithmetic average roughness Ra of the plating layer surface can be measured using a confocal microscope. The lower limit of the arithmetic average roughness Ra on the surface of the plating layer (B) is usually 0.1 μm, and in many cases 0.2 μm. The upper limit of the adhesion strength between the polyester resin molded product (A) and the plating layer (B) is usually 20 MPa, and in many cases 15 MPa.

  The plated polyester resin molded product of the present invention is excellent in reflow resistance. Specifically, when the reflow resistance is evaluated under the condition that the polyester resin molded article (A) of the present invention is passed through a zone set at 260 ° C. in a reflow furnace for 60 seconds, the dimensional change rate is in the longitudinal direction and the width direction. Both are 1% or less. Therefore, the plated polyester resin molded article of the present invention does not cause inconveniences such as swelling and partial peeling of the plating layer in the reflow soldering process.

  The plated polyester resin molded article of the present invention contains a flame retardant in the polyester resin molded article (A), so that the surface smoothness, adhesion strength, reflow resistance, etc. of the plating layer are not impaired. The flame retardancy satisfying the standard value V-0 can be achieved.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

[Example 1]
1. Preparation of polyester resin composition:
Polybutylene terephthalate and glycidyl methacrylate are reacted and mixed to form polybutylene terephthalate that can be cross-linked by irradiation with ionizing radiation, and a resin composition containing a polyfunctional monomer, inorganic filler, and antioxidant is prepared. did.

  That is, for 100 parts by weight of polybutylene terephthalate (PBT), 5 parts by weight of glycidyl methacrylate, 3 parts by weight of triallyl isocyanurate, 43 parts by weight of aluminum borate (average fiber diameter 0.8 μm, aspect ratio 30, pH 6) ( 15% by volume) and 0.1 part by weight of an antioxidant were put into a 20-liter super mixer and premixed at room temperature. The obtained premix is put into a twin-screw mixer (45 mmφ, L / D = 32), melted and mixed at a barrel temperature of 260 ° C. and a screw rotation speed of 100 rpm, extruded from the die into a strand, and the discharged strand is cooled with water. The pellet of the polyester resin composition was produced by the method of cutting.

2. Bending test and sample preparation:
The pellets were injection molded by an injection molding machine with a clamping force of 40 tons under conditions of a barrel temperature of 260 ° C., an injection pressure of 500 kg / cm ² , an injection time of 10 seconds, and a mold temperature of 60 ° C. A plate having a width of 10 mm and a thickness of 4 mm was produced. Next, the obtained plate was irradiated with an electron beam with an acceleration voltage of 3 MeV at 250 kGy to prepare a sample for bending test. The bending test was performed according to ISO178. If this bending strength is 110 MPa or more, it can be evaluated that it has good strength.

3. Reflow resistance test and sample preparation:
The pellets were injection molded by an injection molding machine with a clamping force of 40 tons under conditions of a barrel temperature of 260 ° C., an injection pressure of 500 kg / cm ² , an injection time of 10 seconds, and a mold temperature of 60 ° C. A plate having a width of 10 mm and a thickness of 0.4 mm was produced. Next, the obtained plate was irradiated with 250 kGy of an electron beam having an acceleration voltage of 3 MeV to prepare a sample for a reflow resistance test.

  The reflow resistance test was performed by passing the test sample through a zone set at 260 ° C. in a reflow furnace for 60 seconds and measuring the dimensional change rate. If the dimensional change rates in the longitudinal direction and the width direction of the test sample are both 1% or less, it can be evaluated that the reflow resistance is good.

4). Preparation of plating evaluation sample:
The pellets were injection molded by an injection molding machine with a clamping force of 40 tons under conditions of a barrel temperature of 260 ° C., an injection pressure of 500 kg / cm ² , an injection time of 10 seconds, and a mold temperature of 60 ° C. A plate having a width of 20 mm and a thickness of 1 mm was produced. The obtained plate was etched by dipping in a 45% aqueous sodium hydroxide solution at 85 ° C. for 12 minutes, neutralized with a 4% aqueous hydrochloric acid solution, and then thoroughly washed in running water. Using this plate, the surface thereof was subjected to plating treatment such as electroless copper plating or electrolytic copper plating according to the following procedure, and then irradiated with an electron beam with an acceleration voltage of 3 MeV at 250 kGy. In this manner, a plating evaluation sample having a plating layer formed on the surface and irradiated and cross-linked by ionizing radiation was produced.

i) Electroless copper plating (1) Conditioning:
The plate prepared above was immersed in an aqueous solution containing Neutralizer 3320 (manufactured by Shipley Far East Co., Ltd.) at a concentration of 100 ml / liter at 45 ° C. for 5 minutes, and then washed with ion-exchanged water.

(2) Pre-dip:
The plate was immersed in an aqueous solution containing sodium chloride 180 g / liter, 35% hydrochloric acid 80 ml / liter, Omnishield 1505 [manufactured by Shipley Far East Co., Ltd.] 20 ml / liter at room temperature for 3 minutes.

(3) Catalyst:
The plate was placed in an aqueous solution containing sodium chloride 180 g / liter, 35% hydrochloric acid 100 ml / liter, Omnishield 1505 20 ml / liter, Omnishield 1558 20 ml / liter [manufactured by Shipley Far East Co., Ltd.] at 45 ° C. And then washed with ion-exchanged water.

(4) Accelerator:
The plate was immersed in an aqueous solution containing Omnishield 1560 [manufactured by Shipley Far East Co., Ltd.] 100 ml / liter for 5 minutes at room temperature, and then washed with ion-exchanged water.

(5) Electroless copper plating:
The plate was immersed in an aqueous solution containing Omnishield 1598 (manufactured by Shipley Far East Co., Ltd.) 100 ml / liter at 45 ° C. for 20 minutes to form a copper plating layer having a thickness of 0.5 μm.

ii) Electrolytic copper plating Plates on which an electroless copper plating layer was formed were mixed with 80 g / liter of copper sulfate pentahydrate, 200 ml / liter of sulfuric acid, 147 μl of 35% hydrochloric acid, and 10 ml / liter of Sulcup ETN (manufactured by Uemura Kogyo Co., Ltd.). In the aqueous solution containing it, a current having a current density of 2.5 A / dm ² was passed at room temperature for 23 minutes to form an electrolytic copper plating layer having a thickness of 10 μm.

iii) Electroless nickel plating Furthermore, according to the procedure shown below, the electroless nickel plating process was performed on the copper plating layer.

(1) Degreasing:
The plate on which the copper plating layer was formed was immersed in an aqueous solution containing 100 ml / liter of pre-posit cleaner 742 (manufactured by Shipley Far East Co., Ltd.) at 50 ° C. for 5 minutes, and then washed with ion-exchanged water.

(2) Copper etching:
The plate was immersed in an aqueous solution containing sulfuric acid 10 ml / liter and pre-posit etch 748 (manufactured by Shipley Far East Co., Ltd.) 60 ml / liter at room temperature for 1 minute, and then washed with ion-exchanged water.

(3) Acid cleaning:
The plate was immersed in a 10% aqueous sulfuric acid solution at room temperature for 1 minute and then washed with ion-exchanged water.

(4) Catalyst:
The plate is immersed in 6% hydrochloric acid for 30 seconds at room temperature, and then immersed in an aqueous solution containing 9 ml / liter of 35% hydrochloric acid and 6 ml / liter of Omnishield 1573 (manufactured by Shipley Far East Co., Ltd.) for 1 minute at room temperature. Then, it was washed with ion exchange water.

(5) Electroless nickel plating:
The plate was immersed in an aqueous solution containing 310 ml / liter of Evalon BM2 (manufactured by Shipley Far East Co., Ltd.) for 30 minutes at 85 ° C. to form a nickel plating layer having a thickness of 5 μm.

iv) Gold plating Furthermore, the gold plating process was performed on the nickel plating layer according to the procedure shown below.

(1) Electroless strike plating:
The plate was immersed at 90 ° C. for 10 minutes in an aqueous solution containing 3 g / liter of potassium gold cyanide and 500 ml / liter of Ourolectroles SMT210 (manufactured by Nippon Leonal Co., Ltd.).

(2) Electroless gold plating:
The plate is immersed in an aqueous solution containing potassium gold cyanide 6 g / liter and Ourolectorole SMT301 (manufactured by Nippon Leonal Co., Ltd.) 750 ml / liter at 85 ° C. for 60 minutes to form a gold plating layer having a thickness of 0.5 μm. did.

5. Measurement of surface roughness of plating layer:
The surface roughness of the plating layer was measured using a confocal microscope [Keyence Co., Ltd. VK8550], and the arithmetic average roughness Ra was determined. A surface roughness Ra of 1 μm or less was evaluated as good considering the wire bonding property.

6). Measurement of adhesion strength of plating layer:
The adhesion strength of the plating layer was measured according to the method shown in FIG. That is, a metal wire 4 having a diameter of 1.5 mmφ was set up vertically on the plating layer 2 formed on the surface of the resin molded product 1, and the end thereof was solder-welded onto the plating layer. The diameter of the welded part 3 was 4 mmφ and the height was 2 mm. The metal wire 4 was peeled off at a tensile rate of 10 mm / min in the direction perpendicular to the surface of the plating layer 2, the peel strength at that time was measured, and the measured value was taken as the adhesion strength of the plating layer. If the adhesion strength of the plating layer is 2 MPa or more, it can be evaluated that the adhesion is good.

[Example 2]
Each sample was prepared in the same manner as in Example 1 except that potassium hexatitanate having an average fiber diameter of 0.4 μm, an aspect ratio of 40, and a pH of 7 was used in place of aluminum borate and evaluated in the same manner. The results are shown in Table 1.

[Examples 3 and 4]
In Examples 3 and 4, as shown in Table 1, a flame retardant is added, and the average fiber diameter is 0.1 to 5 μm, the aspect ratio is 5 to 100, and the pH is in the range of 2 to 10 Is an experimental example using a resin composition in which 15% by volume is dispersed in a resin composition. Each sample was produced in the same manner as in Example 1 except that these resin compositions were used, and evaluated in the same manner. Flame retardancy was evaluated by UL94 combustion test. The results are shown in Table 1.

(footnote)
(* 1) Polybutylene terephthalate; manufactured by Toray Industries, Inc., trade name “Trecon 1401-X06”,
(* 2) Aluminum borate fiber (average fiber diameter 0.8 μm, aspect ratio 30, pH 6); manufactured by Shikoku Kasei Co., Ltd., trade name “Arborex Y”,
(* 3) Potassium hexatitanate fiber (average fiber diameter 0.4 μm, aspect ratio 40, pH 7); manufactured by Otsuka Chemical Co., Ltd., trade name “Tismo N”,
(* 4) Brominated flame retardant: Albemarle Japan Co., Ltd., trade name “Cytex BT93”
(* 5) Product name “Nonflex Alba” manufactured by Seikagaku Corporation.

  Examples 1 and 2 are experiments using a resin composition in which inorganic fibers having an average fiber diameter of 0.1 to 5 μm, an aspect ratio of 5 to 100, and a pH of 2 to 10 are dispersed at a ratio of 15% by volume. It is an example. The bending strength was 110 MPa or more, and showed good strength. The rate of dimensional change after the reflow test was 1% or less in both the length direction and the width direction, indicating good reflow resistance. The adhesion strength of the plating layer exceeded 2 MPa in all cases and showed good adhesion strength. The surface roughness Ra was also good at 1 μm or less.

  In Examples 3 and 4, inorganic fibers in each range of average fiber diameter of 0.1 to 5 μm, aspect ratio of 5 to 100, and pH of 2 to 10 were dispersed at a ratio of 15% by volume, and a flame retardant was added. It is an experimental example. The bending strength was 110 MPa or more, and showed good strength. The rate of dimensional change after the reflow test was 1% or less in both the length direction and the width direction, indicating good reflow resistance. The rate of dimensional change after the reflow test was 1% or less in both the length direction and the width direction, indicating good reflow resistance. The adhesion strength of the plating layer all exceeded 2 MPa and showed good adhesion strength. The surface roughness Ra was also good at 1 μm or less. When flame retardancy was evaluated by the UL94 test method, it was found that both can rank V-0.

[Comparative Example 1]
As the resin composition, plating grade LCP [Polyplastic Co., Ltd., trade name “Vectra C820”] was used. The LCP was injection molded by an injection molding machine with a mold shrinkage of 40 tons under the conditions of a barrel temperature of 330 ° C., an injection pressure of 500 kg / cm ² , an injection time of 10 seconds, and a mold temperature of 60 ° C. A shape test sample was prepared. Next, using this sample, plating treatment was performed in the same manner as in Example 1. Various characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[Comparative Example 2]
A sample was prepared in the same manner using the same resin composition as in Comparative Example 1. For the sample for plating evaluation, the etching time with a 45% sodium hydroxide aqueous solution at 85 ° C. was shortened to 3 minutes, and then neutralized with a 4% hydrochloric acid aqueous solution and then thoroughly washed in running water. A plating treatment was performed in the same manner as above, and an electron beam with an acceleration voltage of 3 MeV was irradiated at 250 kGy to obtain a test sample. Various characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[Comparative Example 3]
In Example 1, instead of aluminum borate, an experimental example was conducted in the same manner except that a resin composition in which calcium pyrophosphate having an average particle diameter of 2 μm was dispersed in a resin composition at a ratio of 15% by volume was used. is there. Various characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[Comparative Example 4]
In Example 1, instead of aluminum borate, a resin composition in which calcium silicate having an average fiber diameter of 3 μm, an aspect ratio of 10, and a pH of 10.5 was dispersed in a resin composition at a ratio of 15% by volume was used. Is an example of an experiment conducted in the same manner. Various characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[Comparative Example 5]
In Example 1, it replaced with aluminum borate, and except having used the resin composition which disperse | distributed the glass fiber of average fiber diameter of 13 micrometers, aspect ratio 230, and pH 7 in the ratio of 15 volume% in the resin composition. It is an example of an experiment conducted in Various characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[Comparative Example 6]
A sample was prepared in the same manner using the same resin composition as in Comparative Example 5. For the sample for plating evaluation, the etching time with a 45% sodium hydroxide aqueous solution at 85 ° C. was shortened to 3 minutes, and then neutralized with a 4% hydrochloric acid aqueous solution and then thoroughly washed in running water. A plating treatment was performed in the same manner as above, and an electron beam with an acceleration voltage of 3 MeV was irradiated with 250 kGy to obtain a test sample. Various characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 2.

(footnote)
(* 1) Liquid crystal polymer; manufactured by Polyplastics Co., Ltd., trade name “Vectra C820”
(* 2) Polybutylene terephthalate; manufactured by Toray Industries, Inc., trade name “Trecon 1401-X06”,
(* 3) Made by Kawatetsu Industry Co., Ltd., trade name “Wollastonite”
(* 4) Product name “ECS03T-187” manufactured by Nippon Electric Glass Co., Ltd.
(* 5) Product name “Nonflex Alba” manufactured by Seikagaku Corporation.

  From the results in Table 2, the following can be understood. Comparative Example 1 is an experimental example in which the etching process time of the LCP molded product is lengthened and the adhesion strength of the plating layer is increased, but the surface roughness of the plating layer is increased to 3.4 μm and the smoothness is deteriorated. It was. On the other hand, Comparative Example 2 is an experimental example in which the etching time of the LCP molded product was shortened and the surface roughness of the plating layer was reduced to 1 μm or less, but the adhesion strength of the plating layer was as low as 1.2 MPa. It was inadequate.

  Comparative Example 3 is an experimental example in which calcium pyrophosphate, which is a particulate inorganic substance having an average particle diameter of 2 μm, was mixed, but the bending strength was insufficient at 84 MPa. Comparative Example 4 is an experimental example in which calcium silicate having an average fiber diameter of 3 μm, an aspect ratio of 10, and a pH of 10.5 is mixed, but the dimensional change rate in the longitudinal direction and the width direction after reflowing at 260 ° C. is 1%. The heat resistance was insufficient.

  Comparative Example 5 is an experimental example in which glass fibers having an average fiber diameter of 13 μm, an aspect ratio of 230, and a pH of 7 were mixed, but the surface roughness of the plating layer was increased to 2.8 μm, and the smoothness deteriorated. Comparative Example 6 is an experimental example in which the etching treatment time was shortened and the surface roughness of the plating layer was reduced with the same composition as Comparative Example 5, but the adhesion strength of the plating layer was significantly reduced to 0.9 MPa. It was inadequate.

  The plated polyester resin molded product of the present invention has strength corresponding to downsizing and thinning of electronic equipment, sufficient adhesion strength and a smooth plating layer that can be wire-bonded, and has heat resistance at the reflow temperature. Since it is excellent and can impart a high degree of flame retardancy as required, it can be used in the field of manufacturing electronic parts such as MID used for semiconductor packages.

FIG. 1 is a perspective view showing a method for measuring the adhesion strength of a plating layer to a resin molded product.

Explanation of symbols

1: resin molded product,
2: plating layer,
3: Solder weld,
4: Metal wire.

Claims (4)

It is a plated polyester resin molded article in which a plating layer (B) is formed on the surface of the polyester resin molded article (A) and the polyester resin forming the polyester resin molded article (A) is crosslinked by irradiation with ionizing radiation. And
(A) The bending strength measured according to ISO178 is 110 MPa or more,
(B) The arithmetic average roughness Ra of the plating layer (B) surface is 1 μm or less,
(C) Dimensional change measured under conditions in which the adhesion strength between the polyester resin molded product (A) and the plating layer (B) is 2 MPa or more, and (d) a zone set at 260 ° C. in a reflow furnace is passed for 60 seconds. A plated polyester resin molded product having a rate of 1% or less in both the longitudinal direction and the width direction.   The polyester resin molded product (A) is 5 to 50 inorganic fibers having an average fiber diameter of 0.1 to 5 μm, an aspect ratio of 5 to 100, and a pH of 2 to 10 to a polyester resin that can be cross-linked by irradiation with ionizing radiation. The plated polyester resin molded article according to claim 1, which is a molded article obtained by melt-molding a resin composition dispersed at a volume percentage, which is crosslinked by irradiation with ionizing radiation.   The plated polyester resin molded article according to claim 2, wherein the inorganic fibers are at least one inorganic fiber selected from the group consisting of aluminum borate fibers and potassium hexatitanate fibers. Production of a plated polyester resin molded article in which a plating layer (B) is formed on the surface of the polyester resin molded article (A), and the polyester resin forming the polyester resin molded article (A) is crosslinked by irradiation with ionizing radiation A method,
(I) An inorganic fiber having an average fiber diameter of 0.1 to 5 μm, an aspect ratio of 5 to 100, and a pH of 2 to 10 is dispersed in a proportion of 5 to 50% by volume in a polyester resin that can be cross-linked by irradiation with ionizing radiation. Step 1 of preparing a prepared resin composition;
(II) Step 2 of melt-molding the resin composition into the shape of a polyester resin molded article (A) having a desired shape;
(III) Step 3 of forming a plating layer on the surface of the polyester resin molded product (A); and (IV) Step of irradiating the polyester resin molded product (A) with ionizing radiation before or after step 3 4;
The manufacturing method of the plating polyester resin molded product characterized by including.

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