Laser weldable resin composition, molded article, laser welded article, and method for producing same

Abstract

To provide a resin composition for laser welding capable of improving moisture permeation resistance for a molded article, and to provide a molded article.SOLUTION: A resin composition for laser welding includes a polyester resin (A), an epoxide resin (B), an inorganic filler (C) and a scaly glass (D). The ratio of the scaly glass (D) to a total solid content of the resin composition for laser welding is 10 mass% or more. The epoxy equivalent of the epoxide resin (B) is 150-250 g / eq.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a laser-weldable resin composition and a molded article, and more particularly to a laser-weldable resin composition, a molded article made from the laser-weldable resin composition, a laser-welded article including this molded article, and a method for producing the same. [Background technology]

[0002] Thermoplastic resins are relatively easy to process, and therefore can be used, for example, to produce molded articles by heating, melting, and molding the resin. For example, thermoplastic polyester resins are molded to produce molded articles such as housings and parts.

[0003] Furthermore, various methods are known for joining molded articles such as parts together. One method for joining molded articles made from thermoplastic resin compositions together is laser welding, in which molded articles are joined together by laser irradiation.

[0004] In the laser welding method, a transmissive material capable of transmitting laser light is placed on an absorptive material capable of absorbing laser light, and laser light is then passed through the transmissive material and then reaches the absorptive material. The absorptive material generates heat by absorbing the laser light. This heat melts the absorptive and transmissive materials, thereby welding them together.

[0005] Patent Document 1 discloses a laser-weldable thermoplastic resin composition containing a polyester resin (A), an epoxy resin (B), an inorganic filler (C), and short glass fibers (D) having an average fiber length of 100 μm or less. It is disclosed that this laser-weldable thermoplastic resin composition has excellent laser transmittance, low warpage, and hydrolysis resistance, and is easily welded by laser welding. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-24396 Summary of the Invention [Problem to be solved by the invention]

[0007] The inventors independently conducted research and development into resin compositions for laser welding and found that molded articles made from the resin compositions had problems with moisture permeability.

[0008] An object of the present disclosure is to provide a laser-weldable resin composition that can improve the moisture permeation resistance of a molded article, a molded article, a laser-welded article, and a method for producing a laser-welded article. [Means for solving the problem]

[0009] A laser welding resin composition according to one embodiment of the present disclosure contains a polyester resin (A), an epoxy resin (B), an inorganic filler (C), and glass flakes (D). The proportion of the glass flakes (D) relative to the total solid content of the laser welding resin composition is 10 mass% or more. The epoxy equivalent of the epoxy resin (B) is 150 g / eq or more and 250 g / eq or less.

[0010] A molded article according to one aspect of the present disclosure includes the laser weldable resin composition.

[0011] A laser-welded article according to one aspect of the present disclosure includes the molded article and an absorbing material that has laser light absorption properties, and the molded article and the absorbing material are welded together.

[0012] A method for manufacturing a laser-welded body according to one aspect of the present disclosure includes overlapping the molded body with an absorbing material having laser light absorption properties, and welding the molded body by transmitting laser light through the molded body and then allowing the laser light to be absorbed by the absorbing material. [Effects of the Invention]

[0013] According to one aspect of the present disclosure, a laser-weldable resin composition, a molded article, a laser-welded article, and a method for producing a laser-welded article, which can improve the moisture permeation resistance of a molded article, are obtained. [Brief explanation of the drawings]

[0014] [Figure 1] Fig. 1A is a schematic perspective view showing an example of a welded body produced from a molded body according to one embodiment of the present invention, and Fig. 1B is a cross-sectional view taken along line XX in Fig. 1A. [Figure 2] Fig. 2A is an exploded perspective view of a welded body made from a molded body according to one embodiment of the present invention, Fig. 2B is a schematic perspective view of a welded body obtained by welding together the molding materials (molded bodies) in Fig. 2A, Fig. 2C is an exploded perspective view showing a modified example of a welded body made from a molded body according to one embodiment of the present invention, and Fig. 2D is a schematic perspective view of a welded body obtained by welding together the molded body in Fig. 2C. [Figure 3] FIG. 3 is a schematic perspective view showing an example of a process for laser welding a transmissive material and an absorptive material. [Figure 4] FIG. 4 is a cross-sectional view showing an outline of an evaluation test for evaluating moisture permeability in the examples. [Figure 5] FIG. 5A is a schematic perspective view showing an example of the shape of a glass flake, and FIG. 5B is a schematic plan view of the glass flake in FIG. 5A as seen from above. DETAILED DESCRIPTION OF THE INVENTION

[0015] 1. Overview First, the circumstances leading to the completion of the present invention will be described.

[0016] While conducting research and development on resin compositions for laser welding, the inventors discovered that molded articles made from resin compositions for laser welding may be permeable to moisture and other substances. This can cause deterioration of components such as semiconductor substrates, encapsulants, electronic components, or semiconductor devices placed inside the welded article. It is known that blending fibrous glass, such as glass fiber, as a reinforcing material into a resin composition for laser welding can make it less susceptible to moisture permeation. However, for welded articles that require higher moisture resistance, the inventors discovered that simply blending fibrous glass as a reinforcing material into a resin composition can easily ensure the mechanical strength of the welded article, but is insufficient to improve moisture resistance.

[0017] Therefore, the inventors conducted extensive research to obtain a laser welding resin composition that can maintain the mechanical strength of a molded article without impairing laser light transmittance and can improve the moisture permeation resistance of the molded article, and have completed the present invention. Specifically, the laser welding resin composition of this embodiment (hereinafter also referred to as composition (X)) contains a polyester resin (A), an epoxy resin (B), an inorganic filler (C), and glass flakes (D). The proportion of the glass flakes (D) relative to the total solid content of composition (X) is 10 mass% or more. The epoxy equivalent of the epoxy resin (B) is 150 g / eq. or more and 250 g / eq. or less. Composition (X) of this embodiment can make a molded article 1 produced from composition (X) less susceptible to penetration of moisture, etc., and a molded article 1 with excellent moisture permeation resistance can be obtained from composition (X).

[0018] The reason why the molded article 1 made from the composition (X) of this embodiment has excellent moisture permeation resistance is not exactly clear, but is presumed to be due to the following reasons.

[0019] That is, when a resin-containing composition contains only fibrous glass as a reinforcing material, the fibrous glass has a generally cylindrical shape, which may make it difficult to prevent moisture from penetrating into a molded body produced from the composition. In contrast, when composition (X) contains glass flakes (D) in a proportion of 10 mass% or more relative to the total solid content of composition (X), the glass flakes (D) have a different shape from the fibrous glass, making it easier to prevent moisture from penetrating into molded body 1 produced from composition (X) compared to when composition (X) containing polyester resin (A), epoxy resin (B), and inorganic filler (C) contains only fibrous glass. As a result, in composition (X) of this embodiment, the glass flakes (D) are thought to contribute to improving the moisture permeation resistance of the molded body 1 produced. Note that "moisture permeation resistance" in the present disclosure is an index indicating the resistance to moisture permeation and can be determined by measuring the moisture permeability of the molded body. The moisture permeability can be measured by the method described in the Examples below.

[0020] Furthermore, the composition (X) of this embodiment provides a molded article 1 produced from the composition (X) with good laser transmittance. Therefore, the composition (X) of this embodiment and the molded article 1 produced from the composition (X) can be suitably used, particularly as a transmissive material, for laser welding. Therefore, a welded article 10 can be produced by stacking the molded article 1 (transmissive material 11) produced from the composition (X) on an appropriate absorbing material 2 and then welding them by laser irradiation (see FIG. 1A).

[0021] Furthermore, the glass flakes (D) can have a smaller aspect ratio than fibrous glass, and therefore are less likely to exhibit anisotropy due to shape differences. Therefore, the inclusion of the glass flakes (D) can make the molded body 1 less likely to warp. This increases the adhesive strength between the molded body 1 (transmitting material 11) and the object to be joined (absorbing material 2) when the molded body 1 (transmitting material 11) of composition (X) is laser welded to an appropriate absorbing material 2.

[0022] 2.Details The laser welding resin composition (composition (X)) and the molded article 1 of this embodiment will be described in more detail below. However, the embodiment described below is merely one of various embodiments of the present disclosure. The following embodiment can be modified in various ways depending on the design as long as the object of the present disclosure is achieved.

[0023] [Laser weldable resin composition] As described above, the resin composition (composition (X)) of this embodiment contains the polyester resin (A), the epoxy resin (B), the inorganic filler (C), and the glass flakes (D).

[0024] The injection flow measured when the composition (X) is injected using a 100-ton injection molding machine is preferably more than 60 mm. In this case, the composition (X) can have high fluidity. Therefore, when molding the composition (X), the moldability of the composition (X) can be improved. This injection flow is more preferably 70 mm or more, and even more preferably 75 mm or more. Specifically, the injection flow is measured when a 100-ton injection molding machine (IS-100E manufactured by Toshiba Machine Co., Ltd.) equipped with a bar flow mold is injected into a gate cross-sectional area of ​​5.6 mm. 2 The measurement can be performed under the conditions of a cavity clearance of 8 mm in thickness and 12.8 mm in width, an injection pressure of 137 MPa, and a mold temperature of 80°C.

[0025] Components that can be contained in the composition (X) of this embodiment will be specifically described.

[0026] (polyester resin) The polyester resin (A) is a thermoplastic resin. The polyester resin (A) may contain a crystalline component. When the polyester resin (A) contains a crystalline component, it is more likely to contribute to improving the moisture permeation resistance of the molded article 1 of the composition (X). In the present disclosure, a crystalline component refers to a resin having a crystalline portion in which molecular chains are regularly arranged at or below the crystallization temperature, or a resin having a melting point. The polyester resin (A) may contain an amorphous component that does not have crystallinity.

[0027] The polyester resin (A) preferably contains at least one compound (polymer) selected from the group consisting of polybutylene terephthalate (PBT)-based resins, polyethylene terephthalate-based resins, and polyethylene naphthalate-based resins. Among these, the polyester resin (A) preferably contains at least one of polybutylene terephthalate-based resin (A1) and polyethylene terephthalate-based resin (A2), and more preferably contains both polybutylene terephthalate-based resin (A1) and polyethylene terephthalate-based resin (A2). When the composition (X) contains the polybutylene terephthalate-based resin (A1), the mechanical strength of the molded article 1 produced from the composition (X) can be improved while maintaining high moisture resistance. Furthermore, when the composition (X) contains the polyethylene terephthalate-based resin (A2), the laser transmittance of the molded article 1 of the composition (X) can be further improved. A crystalline resin tends to reduce the laser transmittance of the molding material. However, when the polyester resin (A) contains both a polybutylene terephthalate-based resin (A1) and a polyethylene terephthalate-based resin (A2), the crystallinity of the polyester resin (A) as a whole can be reduced, and therefore the laser light transmittance can be maintained at a good level.

[0028] When the composition (X) contains both the polybutylene terephthalate resin (A1) and the polyethylene terephthalate resin (A2), the mass ratio ((A1) / (A2)) of the polybutylene terephthalate resin (A1) to the polyethylene terephthalate resin (A2) is preferably within the range of 51 / 49 to 90 / 10. Within this range, the moldability of the composition (X) can be maintained well and the laser transmittance can be increased.

[0029] Examples of the polybutylene terephthalate resin (A1) include polymers obtained by polymerizing, by a polymerization method such as polycondensation, a reactive mixture containing a copolymerizable component (also referred to as the first copolymerizable component) containing terephthalic acid or an ester-forming derivative thereof and a copolymerizable component (also referred to as the second copolymerizable component) containing 1,4-butanediol or an ester-forming derivative thereof. The first copolymerizable component is not limited to the above and may further contain an appropriate polycarboxylic acid component. The second copolymerizable component is not limited to the above and may further contain an appropriate polyol component. Examples of the polycarboxylic acid component include at least one compound selected from the group consisting of isophthalic acid, naphthalenedicarboxylic acid, adipic acid, sebacic acid, dodecanedioic acid, and oxalic acid. The polyol component may include at least one compound selected from the group consisting of ethylene glycol, propylene glycol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, polyethylene glycol, poly-1,3-propylene glycol, and polytetramethylene glycol.

[0030] Specific examples of the polybutylene terephthalate resin (A1) include at least one polymer selected from the group consisting of polybutylene terephthalate (PBT), polybutylene (terephthalate / isophthalate), polybutylene (terephthalate / adipate), polybutylene (terephthalate / sebacate), polybutylene (terephthalate / decanedicarboxylate), polybutylene (terephthalate / naphthalate), and poly(butylene / ethylene) terephthalate. In the present disclosure, " / " denotes a copolymer; for example, "polybutylene (A / B)" is a polycondensate of 1,4-butanediol with A and B.

[0031] Examples of the polyethylene terephthalate resin (A2) include polymers obtained by polymerization methods such as polycondensation of a reactive mixture containing terephthalic acid or an ester-forming derivative thereof and ethylene glycol or an ester-forming derivative thereof. Other copolymerization components than those described above may be used as copolymerization components within the scope that does not impair the properties of the polyethylene terephthalate resin (A2). Examples of such other copolymerization components include those similar to the copolymerization components (first copolymerization component and second copolymerization component) in the polybutylene terephthalate resin (A1).

[0032] The proportion of the polyester resin (A) relative to the total solid content of the composition (X) is preferably 35% by mass or more and 85% by mass or less. When the proportion of the polyester resin (A) relative to the total solid content of the composition (X) is 35% by mass or more, the laser transmittance of the molded article 1 can be further improved, and the molded article 1 can achieve better moisture resistance. When the proportion of the polyester resin (A) relative to the total solid content of the composition (X) is 85% by mass or less, the laser transmittance of the molded article 1 can be well maintained, and the molded article 1 can achieve better moisture resistance. The proportion of the polyester resin (A) relative to the total solid content of the composition (X) is more preferably 60% by mass or more and 80% by mass or less, and even more preferably 65% ​​by mass or more and 75% by mass or less.

[0033] (epoxy resin) The epoxy resin (B) has at least one epoxy group per molecule. The epoxy resin (B) has the function of imparting hydrolysis resistance to the composition (X). In this embodiment, the epoxy resin (B) reacts with the ester group of the polyester resin (A) in the composition (X), thereby imparting hydrolysis resistance to the composition (X) and the molded article 1 produced from the composition (X).

[0034] The epoxy resin (B) preferably has, for example, two epoxy groups per molecule. Examples of the epoxy resin (B) include at least one resin selected from the group consisting of bisphenol epoxy resins, novolac epoxy resins, alicyclic epoxy resins; glycidyl ethers, glycidyl esters, glycidyl amines, and heterocyclic epoxy resins. Specific examples of the bisphenol epoxy resin include bisphenol A epoxy resins, bisphenol F epoxy resins, and bisphenol S epoxy resins. Examples of the novolac epoxy resin include phenol novolac epoxy resins, cresol novolac epoxy resins such as o-cresol novolac epoxy resins, bisphenol A novolac epoxy resins, and dicyclopentadiene novolac epoxy resins. Examples of alicyclic epoxy resins include 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexanecarboxylate, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and 1-epoxyethyl-3,4-epoxycyclohexane. Examples of glycidyl esters include phthalic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, and dimer acid glycidyl ester. Examples of glycidyl amines include tetraglycidyldiaminodiphenylmethane, triglycidyl p-aminophenol, and N,N-diglycidylaniline. Examples of heterocyclic epoxy resins include 1,3-diglycidyl-5,5-dimethylhydantoin and triglycidyl isocyanurate. The epoxy resin (B) may be at least one compound selected from the group consisting of the above. In particular, the epoxy resin (B) preferably contains a cresol novolac epoxy resin, and more preferably an o-cresol novolac epoxy resin, which can further improve the hydrolysis resistance of the molded article 1 produced from the composition (X).

[0035] The epoxy equivalent of the epoxy resin (B) is preferably 150 g / eq. or more and 250 g / eq. or less. If the epoxy equivalent of the epoxy resin (B) is 150 g / eq. or more, the reaction between the polyester resin (A) and the epoxy resin (B) can be appropriately suppressed when kneading the components that can be contained in the composition (X). This makes it possible to prevent the fluidity of the composition (X) from becoming excessively high, thereby ensuring good fluidity of the composition (X). Furthermore, if the epoxy equivalent of the epoxy resin (B) is 250 g / eq. or less, hydrolysis of the polyester resin (A) in the composition (X) can be made less likely to occur.

[0036] The epoxy resin (B) may contain an epoxy analogue other than those mentioned above. For example, the epoxy resin (B) may contain a compound having at least one oxetane group in one molecule.

[0037] The proportion of the epoxy resin (B) relative to the total solid content of the composition (X) is preferably 0.5% by mass or more and 7% by mass or less, more preferably 0.5% by mass or more and 5% by mass or less, and even more preferably 1% by mass or more and 2% by mass or less.

[0038] (Inorganic filler) The inorganic filler (C) can contribute to improving the mechanical strength of the molded body 1 produced from the composition (X).

[0039] The inorganic filler (C) preferably has an L value of 90 or more. In this case, the mechanical strength of the molded article 1 produced from the composition (X) can be ensured while maintaining good laser transmittance of the composition (X). In the present disclosure, the L value is a color value in the Lab color system measured with a color difference meter.

[0040] In the present disclosure, the inorganic filler (C) is distinguished from the glass flakes (D) and glass fibers (E) described below. That is, the inorganic filler (C) does not include the glass flakes (D) and glass fibers (E).

[0041] The inorganic filler (C) includes, for example, inorganic oxides, inorganic hydroxides, inorganic nitrides, inorganic carbides, etc. Specific examples of the inorganic filler (C) include at least one material selected from the group consisting of talc, aluminum hydroxide, alumina (aluminum oxide), silica, mica, clay, wollastonite, titanium oxide, barium titanate, silicon nitride, aluminum nitride, boron nitride, silicon carbide, zirconium carbide, and magnesium hydroxide.

[0042] The state of the inorganic filler (C) is not particularly limited as long as it does not deviate from the object of the present disclosure, and the inorganic filler (C) may be, for example, in the form of powder or granules.

[0043] The proportion of the inorganic filler (C) relative to the total solid content of the composition (X) is preferably 0.5% by mass or more and 5% by mass or less. When the proportion of the inorganic filler (C) relative to the total solid content of the composition (X) is within the above range, properties such as mechanical strength can be improved. Furthermore, when the proportion of the inorganic filler (C) relative to the total solid content of the composition (X) is 0.5% by mass or more, the permeability of the molded article 1 can be maintained at a good level. The proportion of the inorganic filler (C) relative to the total solid content of the composition (X) is more preferably 1% by mass or more and 5% by mass or less, and even more preferably 2% by mass or more and 4% by mass or less.

[0044] (flake glass) The composition (X) contains glass flakes (D). In this embodiment, the average thickness t of the glass flakes (D) is 0.1 μm or more and 5 μm or less. The ratio of the average particle diameter a to the average thickness t of the glass flakes (D) (aspect ratio: a / t) is preferably 2 or more and 1000 or less. The average particle diameter a of the glass flakes (D) is the particle diameter (D50) corresponding to a cumulative mass percentage of 50% in a volume-based particle size distribution measured based on a laser diffraction scattering method.

[0045] The average thickness t of the glass flakes (D) is measured by the following method: it is the arithmetic mean value of the thicknesses t of three or more arbitrarily selected portions of the glass flakes (D) measured using a scanning electron microscope (SEM).

[0046] When the glass flake (D) has a shape shown in, for example, FIGS. 5A and 5B , where N is the length of the shortest side in plan view and W is the length of the longest side, the ratio (W / N) of the length W to the length N is preferably 30 or less. The lower limit of the ratio (W / N) of the length W to the length N is not particularly limited, but is preferably 1 or more. The ratio (N / T) of the length N to the thickness T is also preferably 4 or more. The upper limit of the ratio (N / T) of the length N to the thickness T is not particularly limited, but is preferably 1,000 or less. While the shape of the glass flake (D) in plan view is heptagonal in FIG. 5B as an example, it is not limited thereto and may be any other suitable shape. For example, the shape of the glass flake (D) in plan view may be a polygonal shape such as a triangle or a rectangle, or may be a circle, an ellipse, a sector, or the like. The glass flake (D) of this embodiment has a planar shape and a layered structure.

[0047] When the composition (X) contains the glass flakes (D), the molded body 1 produced from the composition (X) is less susceptible to permeation of moisture and the like.

[0048] In this embodiment, the composition (X) contains glass flakes (D), which scatters the laser light more easily when the laser light passes through the composition (X) than a laser welding resin composition containing only glass fiber (E), which will be described later. This makes it possible to appropriately reduce the directionality of the laser light. Therefore, compared to when the composition (X) contains only glass fiber (E) as a reinforcing material, damage such as carbonization (resin burn) is less likely to occur in the resin at the welded portion of the molded article 1. Therefore, the welded article 10 made from the molded article 1 is less likely to deteriorate.

[0049] Although the glass flakes (D) are anisotropic, the anisotropy is sufficiently small compared to fibrous components such as glass fibers (E). Therefore, when a laser is irradiated onto a molded body 1 (transmitting material 11) made from composition (X) and absorbed by an appropriate absorbing material 2 to weld them together, the laser welding strength between the molded body 1 and the absorbing material 2 can be improved.

[0050] The proportion of the glass flakes (D) is 10% by mass or more relative to the total solid content of the composition (X). This allows the molded article 1 of the composition (X) to have high moisture permeation resistance. The upper limit of the proportion of the glass flakes (D) relative to the total solid content of the composition (X) is preferably 40% by mass or less. In this case, the moisture permeation resistance of the molded article 1 can be further improved, and the welding strength by laser welding can also be further improved. The upper limit is more preferably 35% by mass or less.

[0051] The composition of the glass flakes (D) is not particularly limited, but examples of the glass flakes (D) include glass having at least one composition selected from the group consisting of E-glass, A-glass, and C-glass. Among these, the glass flakes (D) preferably contain glass having an E-glass composition.

[0052] (glass fiber) The composition (X) may contain glass fibers (E) as long as the action of the glass flakes (D) is not inhibited. When the composition (X) contains the glass flakes (D), the moisture permeation resistance of the molded article 1 produced from the composition (X) is unlikely to decrease even if the fibrous component, glass fibers (E), is blended. Furthermore, when the composition (X) contains the glass flakes (D) and the glass fibers (E), the mechanical strength of the molded article 1 produced from the composition (X) can be further improved.

[0053] The glass fiber (E) is a glass containing sodium silicate that has been fibrous and has a substantially cylindrical shape. Specifically, the glass fiber (E) in the present disclosure preferably satisfies the following relational expressions: 1000≦S≦15000, 5≦T≦20, and 50≦S / T≦3000, where S [μm] is the average length and T [μm] is the average fiber diameter. For this reason, the glass fiber (E) is distinguished from the above-mentioned glass flake (D). The average fiber diameter and average fiber length of the glass fiber (E) can be obtained, for example, by measuring with a microscope.

[0054] When the composition (X) contains glass fiber (E), the proportion of the glass fiber (E) relative to the total solid content of the composition (X) is preferably 10% by mass or more and 20% by mass or less. In this case, the mechanical strength of the molded body 1 can be further increased. In this embodiment, the upper limit of the proportion of the glass fiber (E) relative to the total solid content of the composition (X) is, for example, 20% by mass.

[0055] Composition (X) may contain components other than those described above, such as additives, as long as they do not deviate from the objectives of the present disclosure.

[0056] Examples of the additives include a mold release agent, a thickener, an antifoaming agent, a heat stabilizer, an antioxidant, a lubricant, and an ultraviolet stabilizer.

[0057] Examples of the release agent include fatty acids such as stearic acid, montanic acid, and myristic acid, metal salts of fatty acids such as zinc stearate and calcium stearate, surfactants such as phosphate esters, carnauba wax, and polyethylene wax.

[0058] Examples of the thickener include oxides or hydroxides of at least one divalent metal selected from the group consisting of magnesium, calcium, zinc, and strontium, and acrylic polymers.

[0059] The antifoaming agent may be, for example, a silicone-based antifoaming agent, and specifically, there are oil-type, solution-type, powder-type, emulsion-type, and the like.

[0060] The composition (X) is prepared, for example, as follows.

[0061] First, a mixture is prepared by adding polyester resin (A), epoxy resin (B), inorganic filler (C), and, if necessary, appropriate additives to a container. Mixing can be performed using a mixer such as a tumbler mixer or a Henschel mixer, or a blender. The mixing time is not particularly limited as long as the components are uniformly mixed, and can be any appropriate time. The mixture is then kneaded while being heated using an appropriate device. Examples of kneading devices include a twin-screw extrusion kneader, a kneader, a roll, a disperser, an azimuth homomixer, a planetary mixer, and a crusher. The mixture is then melted, and glass flakes (D) and, if necessary, glass fibers (E) are added. The mixture is then further kneaded to obtain a kneaded mixture. The kneading temperature can be adjusted appropriately depending on the composition of composition (X), but is preferably between 220°C and 280°C. The kneading time is not particularly limited as long as composition (X) can be uniformly kneaded. The kneaded mixture is then cooled to an appropriate temperature to solidify. This gives composition (X). Composition (X) may be cut into pellets using an appropriate granulating device such as a pelletizer. In this case, the size of the pellets of composition (X) can be, for example, 2 to 4 mm. This gives composition (X) in the form of pellets.

[0062] [Molded body] In this embodiment, the molded body 1 can be produced from the composition (X) prepared above. That is, the molded body 1 contains the above-mentioned composition (X). Therefore, the composition (X) can be molded by heating and melting it to produce the molded body 1. The molded body 1 produced from the composition (X) can have excellent laser transmittance. Therefore, the molded body 1 produced from the composition (X) can be suitably used as a transmitting material 11 for laser welding.

[0063] The molded article 1 made from the composition (X) is, for example, a transparent material 11 that can transmit laser light. Therefore, by performing laser welding using the transparent material 11, a resin molded article (welded article 10) with a more complex shape can be obtained. For example, a resin molded part for sealing an electric circuit or the like in an electronic control part such as an engine control unit (ECU) or a sensor can be obtained. That is, the composition (X) of this embodiment is a thermoplastic resin composition for laser welding that constitutes the transparent material 11 that transmits laser light in the laser welding method.

[0064] As described above, the composition (X) of this embodiment reduces defects on the welded surface when a transparent material 11 made from the composition (X) is layered on an appropriate absorbing material and irradiated with a laser. Conventionally, when a molded body made from a resin composition containing fibrous glass is used as a transparent material in laser welding, carbonization of the resin within the molded body can result in resin deterioration (resin discoloration). Resin discoloration due to laser light is more likely to occur at the corners of the welded surface, particularly. However, in this embodiment, the composition (X) contains glass flakes (D), which can appropriately reduce the directionality of the laser light at the welded surface. Therefore, even when welding a molded body 1 having many corners, such as those shown by the dashed-dotted lines in Figures 2C and 2D, damage such as resin discoloration is less likely to occur. Even molded bodies 1 with more complex shapes are less likely to experience deterioration at the welded area.

[0065] The molded body 1 of this embodiment can be used as part of a container for disposing and sealing a device such as a semiconductor device 100 inside. For example, as shown in FIGS. 1A and 1B, in a welded body 10 made from a molded body 1 (transmissive material 11) and an absorbent material 2, the transmissive material 11 shields the interior space from the outside. Specifically, in the welded body 10, the absorbent material 2 functions as a main body having a recess, and the transmissive material 11 functions as a lid that closes the recess in the main body. When the recess in the absorbent material 2 (main body) is closed with the transmissive material 11 (lid), the space surrounded by the inner surface of the recess and the lid becomes the interior space. A semiconductor device 100 or the like can be disposed in the interior space. In FIGS. 1A and 1B, as a specific example, the semiconductor device 100 is disposed in the interior space of the welded body 10, which is fabricated by overlapping and welding the molded body 1 (transmissive material 11) to the absorbent material 2. The semiconductor device 100 includes a substrate 120, a mounting component 130, and a sealing material 140. The substrate 120 includes a conductor wiring 121. The mounting component 130 includes a bump electrode 131, which is mounted to the substrate 120 via solder 132 on the conductor wiring 121. The sealing material 140 seals at least a portion of the gap between the substrate 120 and the mounting component 130. The molded body 1 produced from the composition (X) of this embodiment has excellent moisture permeation resistance, making it difficult for moisture to reach the semiconductor device 100 placed in the internal space of the welded body 10. Therefore, the semiconductor device 100 device is less susceptible to deterioration due to moisture, etc. This improves the reliability of electronic devices such as the semiconductor device 100. Note that the components placed within the welded body 10 are not limited to electronic devices such as the semiconductor device 100, and may be any appropriate components depending on the purpose.

[0066] Furthermore, according to this embodiment, the transparent material 11 and the absorbing material 2 can be laser-welded together to form a sealed enclosure, compared to conventional methods of placing a metal plate to prevent moisture from penetrating into the interior of a housing made from a molded body or sealing the entire electronic device placed inside the housing with resin. Therefore, in this embodiment, the number of components required to produce the product can be reduced, and the manufacturing process can be simplified, thereby reducing the manufacturing cost of the product. Furthermore, because the transparent material 11 made from composition (X) can be used to weld and seal the recesses in the absorbing material 2, the molded body 1 made from composition (X) can also contribute to reducing the weight of the entire product compared to conventional methods.

[0067] To produce the molded article 1, for example, the prepared composition (X) is molded into an appropriate shape by, for example, injection molding, to obtain the molded article 1. Specific examples of injection molding include high-speed injection molding and injection compression molding. High-speed injection molding and injection compression molding have excellent moldability. The conditions for injection molding may be appropriately adjusted depending on the composition and physical properties of the composition (X) and the molded article 1 to be produced.

[0068] The injection compression molding method can be carried out by any suitable operation. For example, the injection molding mold can be opened slightly wider than the thickness of the molded body 1 (e.g., a molded part for laser welding) to be produced, and molten composition (X) is injected to fill the thin-walled portion with composition (X), and then the mold can be closed, thereby producing a molded body 1 having a desired shape.

[0069] The molded article 1 made from the composition (X) has a moisture permeability of 10 g / m 2 It is preferable that the moisture permeability is less than 24 hours. In this case, for example, if a housing (molded body 1) for arranging an electronic device or the like is made from composition (X), and the electronic device or the like is placed inside this housing, and the housing is sealed with a lid of molded body 1 and sealed by welding, moisture is unlikely to penetrate into the sealed housing. Therefore, moisture is unlikely to reach the electronic device or the like, and this makes it possible to prevent deterioration of the electronic device or the like. The moisture permeability of molded body 1 is 7 g / m 224 hours or less is preferable, 5g / m 2 It is more preferable that the moisture permeability of the molded body 1 is 24 hours or less, and ideally, the moisture permeability of the molded body 1 is 0 g / m 2 In the present disclosure, "moisture permeability" is an index showing the ease of moisture permeation. Specifically, moisture permeability can be measured and calculated by the method described in Example "(4-2) Moisture permeability (moisture permeability resistance)" below.

[0070] The laser transmittance of the molded body 1 is preferably greater than 49%. In this case, when the molded body 1 is used as the transmissive material 11, even if the transmissive material 11 and the absorbing material 2 are overlapped and the laser light is transmitted from the transmissive material 11 side, the laser light transmitted through the transmissive material 11 can be made to reach the absorbing material 2 effectively. This makes the molded body 1 suitable for use as the transmissive material 11 for laser welding. The laser transmittance in the present disclosure is obtained by measuring the transmittance when irradiated with light having a wavelength of 1064 nm.

[0071] The anisotropy of the molded body 1 is preferably less than 0.5. In this case, warping of the welded portion of the molded body 1 can be reduced when the molded body 1 is laser welded. This allows for increased laser welding strength of the welded body 10 produced from the molded body 1. The anisotropy of the molded body 1 is more preferably 0.2 or less, and ideally, the anisotropy of the molded body 1 is 0. In the present disclosure, "anisotropy" can be determined from a value calculated from the molding shrinkage of the molded body 1 measured in accordance with ISO 294-4. Specifically, a flat molded body 1 is produced, and the molding shrinkage of the molded body 1 is measured in both the vertical and horizontal directions to obtain the molding shrinkage in the vertical direction and the molding shrinkage in the horizontal direction. The difference between these molding shrinkages is taken as the degree of anisotropy, and the degree of anisotropy is determined based on the degree of anisotropy. Details of the measurement method are as described in the Examples below.

[0072] [Laser welded body] The laser-welded article 10 includes a molded article 1 and an absorbing material 2 that has laser light absorption properties. The welded article 10 is formed by welding the molded article 1 and the absorbing material 2. In this embodiment, the molded article 1 is a transparent material 11 made from the composition (X) described above.

[0073] The tensile strength of the molded body 1 made from the transparent material 11 is preferably greater than 80 MPa. In this case, the mechanical strength of the welded body 10 made from the molded body 1 can also be made excellent. The tensile strength of the molded body 1 is more preferably 110 MPa or greater. There is no particular upper limit to the tensile strength of the molded body 1. The tensile strength of the molded body 1 in the present disclosure can be obtained by measuring a test piece of a dumbbell molded product using a universal material testing machine (autograph) in accordance with ISO 527-1, 2. Specific measurement methods can be used as described in the Examples below.

[0074] To prepare the laser-welded article 10 by welding the molded article 1 (transmitting material 11) made from the composition (X) and an appropriate absorbing material 2, for example, the following procedure may be performed.

[0075] First, a laser-transmittable molded article 1 (transmittable material 11) obtained from the above-mentioned composition (X) is brought into contact with an appropriate laser-absorbent molded article (absorbent material 2). At this time, it is preferable to apply a certain amount of pressure between the two resin materials to increase adhesion, in order to increase welding strength. Then, a laser beam with a wavelength of 880 to 1200 nm is irradiated from the surface of the transmittable material 11 toward the contact surface between the transmittable material 11 and the absorbent material 2. The surface of the transmittable material 11 refers to the side that is not in contact with the absorbent material 2.

[0076] By doing so, the laser light that has passed through the transparent material 11 reaches the absorbing material 2, where it generates heat and melts. At the same time, heat is transferred to the transparent material 11 that is in contact with the melted portion, causing the transparent material 11 to melt as well. As a result, the transparent material 11 and the absorbing material 2 are welded together. Furthermore, according to this method, the portion irradiated with the laser light is welded, so by scanning the irradiated position of the laser light, a resin molded product (welded body 10) in which only the desired portion is welded can be obtained (see FIG. 3). Note that FIG. 3 shows a specific example of laser welding. The cylindrical rod in FIG. 3 represents the laser light, and the trajectory indicated by the dashed line on the contact surface between the molded product 1 (transparent material 11) and the absorbing material 2 represents the portion that is welded by the laser irradiation and scanning. Also, in FIG. 3, the molded product is in the shape of a rectangular prism, but as mentioned above, it is not limited to this and may have any suitable shape.

[0077] The absorbing material 2 is not particularly limited as long as it is a member made of a thermoplastic resin composition that can absorb laser light and melts when the laser light is absorbed. The absorbing material 2 preferably contains the above-described glass flakes in the thermoplastic resin composition. That is, the absorbing material 2 preferably contains glass flakes. In this case, the moisture permeation resistance of a molded product made from the absorbing material 2 can be improved.

[0078] The laser light source used for laser welding is not particularly limited as long as it emits laser light with a wavelength of 880 to 1200 nm. Specific examples include YAG lasers, Nd:YAG lasers, and semiconductor lasers. The output of the laser light can be adjusted appropriately depending on the composition of the composition and the thickness of the resin workpiece, but is preferably, for example, about 10 W to 80 W. The scanning speed of the laser light is preferably, for example, about 10 mm / sec to 3000 mm / sec in terms of weld strength, etc.

[0079] The welding strength of the welded body 10 made from the molded body 1 is preferably greater than 500 N. In this case, the mechanical strength of the welded body 10 made from the transmissive material 11 made from the composition (X) and an appropriate absorbing material 2 can be further improved. This allows for good protection of electronic devices and the like placed inside the molded body 1. The welding strength of the molded body 1 is more preferably 600 N or more, and even more preferably 700 N or more. There is no particular upper limit to the welding strength of the molded body 1. The "welding strength" in the present disclosure can be measured by the method described in the Examples below. [Example]

[0080] The present disclosure will be described in more detail below with reference to examples. However, the present disclosure is not limited to the following examples, and various modifications can be made depending on the design as long as the object of the present disclosure is achieved.

[0081] (1) Preparation of resin composition First, the components shown in the composition column of Table 1 were prepared. The "polyester resin," "epoxy resin," and "inorganic filler" were mixed in a blender, and the glass flakes were added in the amount (parts by mass) shown in Table 1. The mixture was then kneaded in a twin-screw extruder kneader with the cylinder heated to 260°C. In Examples 4 to 6, "glass fiber" was added in addition to the "glass flakes," while in Comparative Examples 1 to 3, only "glass fiber" was added instead of the "glass flakes," and each mixture was further kneaded to prepare a kneaded product. In this way, the resin compositions of each Example and Comparative Example were obtained.

[0082] (2) Preparation of pellets of resin composition The resin composition (kneaded product) obtained in (1) above was cooled in water and then cut into pellets of about 2 to 4 mm using a pelletizer, thereby obtaining pellets of the resin composition.

[0083] The details of the components shown in the composition column in the table are as follows: The values ​​shown in the table represent parts by mass except for "A1 / A2," and the "A1 / A2" column indicates the ratio of polyester resin 1 (A1) to polyester resin (A2). -Polyester resin Polyester resin 1 (A1): Polybutylene terephthalate (PBT) resin (manufactured by Toray Industries, Inc., product name Toraycon PBT1200). Polyester resin 2 (A2): Polyethylene terephthalate (PET) resin (manufactured by Kuraray Co., Ltd., product name Kurapet PETKL236R). -Epoxy resin Epoxy resin 1: o-cresol novolac epoxy resin (epoxy equivalent 210g / eq.). -Inorganic fillers Talc: Micron White #500S (L value 95) manufactured by Hayashi Corporation. -Flake glass Glass flake 1: Product name MEG160FY-M01, manufactured by Nippon Sheet Glass Co., Ltd. Micro Glass Fine Flake (registered trademark). (E glass. Average thickness t: 0.7 μm, average particle size a: 160 μm.) Glass flake 2: Product name REF-015, manufactured by Nippon Sheet Glass Co., Ltd. (E glass. Average thickness t: 5±2 μm, average particle size a: 15 μm.) -glass fiber Glass fiber: Nippon Electric Glass Co., Ltd. Product name: ECST-187 (average fiber length 3 mm, average fiber diameter 13 μm, aspect ratio 231).

[0084] (3) Preparation of the molded body The pellets of the resin composition prepared in (2) were dried in a thermostatic chamber for 4 hours at 140° C. The moisture content of the resulting dried product was 0.2% or less.

[0085] Next, a test piece (specimen) was prepared using an 80t injection molding machine (ES-1000 manufactured by Nissei Plastic Industrial Co., Ltd.). The injection molding conditions were a cylinder temperature of 260°C and a mold temperature of 40°C. This resulted in a test piece (specimen) of 60mm x 60mm x 1mmt. In the following (4-2), a test piece (specimen) of 110mm x 110mm x 1mmt was prepared under the same conditions as above and used for evaluation tests.

[0086] (4) Evaluation (4-1) Injection flow (fluidity) 100t injection molding machine and bar flow mold (gate cross section: 5.6mm 2 The resin composition prepared in (1) above was molded into a mold cavity (cavity clearance: thickness 8 mm, width 12.8 mm) under conditions of an injection pressure of 137 MPa and a mold temperature of 80°C, and the length of the molded article thus obtained was measured as the flow length. The results obtained were evaluated according to the following criteria. A: The flow length is 75 mm or more. B: The flow length is greater than 65 mm and less than 75 mm. C: The flow length is 65 mm or less.

[0087] (4-2) Moisture permeability (moisture permeability) First, a metallic moisture permeable cup 50 having a cylindrical shape with a bottom as shown in Fig. 4 was prepared. A moisture absorbent 60 (total mass Ma [g] of the moisture absorbent before the test) was placed in the moisture permeable cup 50. The metallic moisture permeable cup 50 is a container conforming to JIS Z0208 (Test method for moisture permeation of moisture-proof packaging materials).

[0088] Next, in the same manner as in (3), a test piece of molded body 1 measuring 110 mm × 110 mm × 1 mmt was prepared from the resin composition, and this test piece was used to cover the opening of moisture permeable cup 50 containing moisture absorbent 60, and fixed with multiple screws 51 and multiple bolts 52 as shown in Figure 4.

[0089] The moisture-permeable cup 50 covered with the molded article 1 of the resin composition was placed in a constant temperature and humidity tester (SXN-402 manufactured by Kusumoto Chemicals Co., Ltd.) and allowed to stand for 72 hours under conditions of 85°C / 85% RH. After 72 hours, the increase in the mass of the entire cup (the difference between the weight of the entire cup before the test and the weight of the entire cup after the test) was calculated as the amount of water vapor transmitted, and the moisture permeability (moisture permeability resistance) was evaluated. A: The permeability is 5.0 g / m 2 - Less than 24 hours. B: Permeability is 5.0 g / m 2 ·Over 24 hours 10g / m 2 Less than 24 hours. C: Permeability is 10 g / m 2 - 24 hours or more.

[0090] (4-3) Laser light transmittance The transmittance of laser light (wavelength 1064 nm) was measured for the test piece (60 mm × 60 mm × 1 mm) prepared in (3) above using a spectrophotometer (Shimadzu UV-3100). The results were evaluated according to the following criteria. A: Laser light transmittance is 65% or more. B: Laser light transmittance is more than 49% and less than 65%. C: Laser light transmittance is 49% or less.

[0091] (4-4) Resin discoloration on the welded surface (deterioration of the joint due to welding) In the above (1), a resin composition for laser absorption was separately prepared by adding 1% by mass of carbon black as a laser light absorber. This resin composition was molded in the same manner as in the above (2) and (3) to obtain a molded body (absorbent material), and a test piece (60 mm × 60 mm × 1 mmt) of this absorbent material was prepared.

[0092] The test piece (transmitting material) prepared in (3) above and the test piece (absorbing material) above were overlapped, and a weight (200 N) was applied. Next, a laser beam with a wavelength of 1064 nm was irradiated from the surface of the transmitting material opposite the surface facing the absorbing material toward the contact surface between the transmitting material and the absorbing material. The laser beam irradiation conditions were an output of 15 W, a scanning speed of 200 mm / s, and a laser beam diameter (diameter) of 1.0 mm. This resulted in a molded product (welded body) in which the transmitting material and the absorbing material were welded together with a welding length of 8 mm.

[0093] The welded body was visually inspected near the joint to check for any resin discoloration near the joint, and evaluated according to the following criteria: "Resin discoloration" refers to a carbonization phenomenon that occurs when excessive energy is applied to the molten part of the transparent material. A: No resin discoloration has occurred. C: Resin discoloration has occurred over a wide area.

[0094] (4-5) Welding strength The test piece (60mm x 60mm x 1mmt) of the welded body obtained in (4-4) above was sandwiched between the permeable material side and the absorbent material side in a universal testing machine (autograph), and a tensile breaking load test was performed to measure the weld strength. The measurement results obtained were evaluated according to the following criteria. A: The welding strength was 700N or more. B: The welding strength was greater than 500N and less than 700N. C: The welding strength was 500N or less.

[0095] (4-6) Anisotropy (mold shrinkage) The mold shrinkage in the perpendicular and parallel directions was measured for a 60mm x 60mm x 2mmt test piece in accordance with ISO-294-4. The difference between the obtained mold shrinkage in the perpendicular direction and the mold shrinkage in the parallel direction was defined as anisotropy, and the anisotropy was evaluated according to the following criteria. A: Anisotropy was 0.2 or less. B: The anisotropy was greater than 0.2 and less than 0.5. C: Anisotropy was 0.5 or more.

[0096] (4-7) Tensile strength Dumbbell test pieces were prepared from the molded articles of each Example and Comparative Example, and their tensile strength was measured using a universal testing machine (autograph) in accordance with ISO 527-1, 2. The dimensions of the dumbbell test pieces were a total length of 173 mm, a parallel portion length of 8 mm, a parallel portion width of 10 mm, and a thickness of 4 mm. Based on the measurement results obtained, the tensile strength of the molded articles was evaluated according to the following criteria. A: The tensile strength was 110 MPa or more. B: The tensile strength was more than 80 MPa and less than 110 MPa. C: The tensile strength was 80 MPa or less.

[0097] [Table 1]

[0098] [Table 2] [Explanation of symbols]

[0099] 1. Molded body 2. Absorbent materials 11 Transparent material 10 Welded body

Claims

1. A laser weldable resin composition containing a polyester resin (A), an epoxy resin (B), an inorganic filler (C), glass flakes (D), and glass fibers (E), a ratio of the inorganic filler (C) to the total solid content of the laser welding resin composition is 0.5% by mass or more and 5% by mass or less, the proportion of the glass flakes (D) relative to the total amount of solids in the resin composition for laser welding is 10% by mass or more, a ratio of the glass fiber (E) to the total solid content of the resin composition for laser welding is 10% by mass or more and 20% by mass or less, The epoxy equivalent of the epoxy resin (B) is 150 g / eq. or more and 250 g / eq. or less. Laser weldable resin composition.

2. The epoxy resin (B) contains a cresol novolac epoxy resin. The laser weldable resin composition according to claim 1.

3. the average thickness of the glass flakes (D) is 0.1 μm or more and 10 μm or less; When the value of the average thickness is t and the value of the average particle diameter is a, the ratio represented by a / t is 2 or more and 1000 or less. The laser weldable resin composition according to claim 1 or 2.

4. The ratio of the polyester resin (A) to the total solid content of the laser welding resin composition is 35% by mass or more and 85% by mass or less. The resin composition for laser welding according to claim 1 .

5. The polyester resin (A) contains a polybutylene terephthalate-based resin (A1) and a polyethylene terephthalate-based resin (A2). The resin composition for laser welding according to claim 1 .

6. the mass ratio ((A1) / (A2)) of the polybutylene terephthalate-based resin (A1) to the polyethylene terephthalate-based resin (A2) is within the range of 51 / 49 to 90 / 10; The laser weldable resin composition according to claim 5.

7. The L value of the inorganic filler (C) is 90 or more. The laser weldable resin composition according to claim 1 .

8. The ratio of the epoxy resin (B) to the total solid content of the laser welding resin composition is 0.5 mass% or more and 7 mass% or less. The resin composition for laser welding according to claim 1 .

9. A laser welding resin composition comprising the resin composition according to any one of claims 1 to 8. Molded body.

10. A transparent material for laser welding, The molded article according to claim 9.

11. A method for manufacturing a laser beam irradiation apparatus comprising the molded body according to claim 9 or 10 and an absorbing material having laser light absorption properties, The molded body and the absorbent material are welded together. Laser welded body.

12. A method of welding a molded body according to claim 9 or 10 by superimposing the molded body on an absorbing material having laser light absorption properties, transmitting laser light through the molded body, and then allowing the laser light to be absorbed by the absorbing material. A method for manufacturing a laser welded product.

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