Resin composition for optical connecting part, mt ferrule, and method for producing resin composition for optical connecting part

Abstract

To provide a resin composition for an optical connection component capable of achieving both suppression of loss fluctuation due to temperature rise and excellent PC connection.SOLUTION: The resin composition for an optical connecting part of the present invention contains a base resin and an inorganic filler, wherein the base resin has a glass transition point of 85 °C or more, the mass of a residue obtained by heating the resin composition for an optical connecting part at 700 °C is 68.0% or more and 74.4% or less based on the mass of the resin composition for an optical connecting part, and the resin composition for an optical connecting part has a Rockwell hardness of 97.1 or more and 106.8 or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a resin composition for optical connecting parts, an MT ferrule, and a method for producing a resin composition for optical connecting parts. [Background technology]

[0002] Optical connecting components for connecting optical fibers are known. The optical connecting components are provided with an optical fiber insertion hole and a guide pin insertion hole. By inserting an optical fiber into the optical fiber insertion hole, the end face of the optical fiber is fixed. Then, by inserting a guide pin of one optical connecting component into the guide pin insertion hole of another optical connecting component, the optical connecting components are connected to each other so that the end faces of the optical fibers face each other. This achieves a PC (Physical Contact) connection between the optical fibers.

[0003] When optical connecting parts are deformed due to a rise in temperature, the position of the optical fiber end face shifts, causing a change in the connection loss of the optical connecting parts. In order to suppress the change in connection loss due to a rise in temperature, a technique of incorporating an inorganic filler into a resin composition for optical connecting parts is known. The resin composition for optical connecting parts disclosed in Patent Document 1 contains 80 to 90% by weight of spherical silica microparticles, and reduces the connection loss of optical connecting parts due to a rise in temperature. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-29415 Summary of the Invention [Problem to be solved by the invention]

[0005] However, if the inorganic filler content is too high, the optical connection component becomes too rigid, resulting in increased resistance when inserting the guide pins into the guide pin insertion holes. In this case, the end faces of the optical fibers cannot be brought close enough together, which can lead to poor PC connection. Therefore, it can be difficult to suppress loss fluctuations due to temperature rise while still achieving a good PC connection.

[0006] An object of the present invention is to provide a resin composition for optical connecting components that can suppress loss fluctuations due to temperature rise and achieve good PC connections at the same time. [Means for solving the problem]

[0007] According to one aspect of the present invention, there is provided a resin composition for optical connection parts, comprising a base resin and an inorganic filler, wherein the glass transition point of the base resin is 85°C or higher, the mass of a residue obtained by heating the resin composition for optical connection parts at 700°C is 68.0% or more and 74.4% or less of the mass of the resin composition for optical connection parts, and the Rockwell hardness of the resin composition for optical connection parts is 97.1 or more and 106.8 or less.

[0008] According to another aspect of the present invention, there is provided a method for producing a resin composition for optical connection components, comprising a first step of kneading a base resin and an inorganic filler, and a second step of injection molding the mixture obtained from the first step, wherein the glass transition point of the base resin is 85°C or higher, the mass of the residue obtained by heating the resin composition for optical connection components at 700°C is 68.0% or more and 74.4% or less of the mass of the resin composition for optical connection components, and the Rockwell hardness of the resin composition for optical connection components is 97.1 or more and 106.8 or less. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a resin composition for optical connecting components that can suppress loss fluctuation due to temperature rise and achieve good PC connection at the same time. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is an external view of a ferrule according to an embodiment of the present invention. [Figure 2] 3 is a flowchart illustrating a method for manufacturing a ferrule according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Elements having common functions throughout the drawings will be designated by the same reference numerals, and duplicate descriptions may be omitted or simplified.

[0012] A resin composition (resin composition for optical connecting parts) according to an embodiment of the present invention will be described using a ferrule (optical connecting part) used in an optical fiber connector as an example.

[0013] Fig. 1 is an external view of a ferrule according to this embodiment. The ferrule is used as an optical connector for optically connecting optical fibers. While Fig. 1 shows a ferrule for an MT (Mechanically Transferable) connector, the ferrule according to this embodiment may also be an MPO (Multifiber Push-On) connector or the like.

[0014] 1, the ferrule 10 has a substantially rectangular parallelepiped shape, and an end face 18 of the ferrule 10 has a plurality of optical fiber insertion holes 12 formed therein. The optical fiber core 14 includes a plurality of optical fibers 16, and the optical fibers 16 are inserted into the optical fiber insertion holes 12 and fixed therein with an adhesive or the like. The end face 18 is polished, for example, by PC (Physical Contact) polishing, SPC (Super PC) polishing, UPC (Ultra PC) polishing, APC (Angled PC) polishing, or the like. This allows the optical fibers to protrude from the end face 18, enabling the optical fibers 16 to be connected to each other.

[0015] It is not necessary that multiple optical fiber insertion holes 12 are formed in the ferrule 10. When the optical fiber core 14 is a single-core core containing a single optical fiber 16, a single optical fiber insertion hole 12 is formed in the ferrule 10.

[0016] The ferrule 10 is further formed with a pair of guide pin insertion holes 20. The pair of guide pin insertion holes 20 are formed in the ferrule 10 so as to be located on both sides of the plurality of optical fiber insertion holes 12. The pair of guide pin insertion holes 20 are each formed in the ferrule 10 along the connection direction of the optical fibers 16. A guide pin 22 for alignment is inserted into each of the pair of guide pin insertion holes 20.

[0017] A guide pin 22 is inserted into each guide pin insertion hole 20 of the pair of ferrules 10, and the two ferrules 10 are aligned. The two end faces of the optical fiber 16 come into contact with each other, and the two ferrules 10 are fixed by a fixing jig such as a clip. This connects the optical fibers 16. Note that the configuration for aligning and fixing the two ferrules 10 is not limited to this. The two ferrules 10 may also be aligned and fixed via an adapter, for example.

[0018] Next, the resin composition used for the ferrule will be described. The resin composition is injected into a mold to produce the ferrule 10 as an injection molded product.

[0019] The resin composition of this embodiment contains a base resin and an inorganic filler. The base resin and the inorganic filler are described in detail below. The resin composition may further contain a colorant such as carbon black and a silane coupling agent.

[0020] [Base resin] The base resin is a matrix resin that constitutes the continuous phase of the ferrule 10. The base resin may be a thermoplastic resin or a thermosetting resin. When the base resin is a thermoplastic resin, examples of the base resin include polyarylene sulfide, polyphenylene sulfide (PPS) resin, polyether ether ketone (PEEK) resin, polystyrene (PS) resin, polymethyl methacrylate (PMMA) resin, polycarbonate (PC) resin, polysulfone (PSU) resin, and polyimide (PI) resin. When the base resin is a thermosetting resin, examples of the base resin include epoxy resin.

[0021] From the viewpoint of the fluidity of the resin composition, the base resin is preferably a PPS resin. The PPS resin may be a linear PPS resin, a semi-linear (semi-crosslinked) PPS resin, or a crosslinked PPS resin.

[0022] The base resin is not limited to one type of resin, but may be composed of multiple types of resin. For example, the base resin may include PPS resin and PEEK resin. Furthermore, the base resin may include multiple different grades of resin of the same type. For example, the base resin may include semi-linear PPS resin and cross-linked PPS resin. The structure and molecular weight of the base resin are selected appropriately depending on the properties required for the ferrule 10.

[0023] The glass transition point of the base resin is preferably 85°C or higher. If the glass transition point of the base resin is lower than 85°C, the optical connecting component may soften at temperatures of 85°C or higher. Furthermore, if the base resin is a thermoplastic resin, the base resin is preferably a crystalline polymer. By selecting a crystalline polymer as the base resin, the softening rate at temperatures higher than the glass transition point can be reduced. This effectively suppresses fluctuations in connection loss of the optical connecting component due to temperature increases.

[0024] [Inorganic filler] The inorganic filler is contained in the resin composition for the purposes of reducing the molding shrinkage rate of the ferrule 10, reducing the linear expansion coefficient, and improving the dimensional accuracy. The inorganic filler has a small linear expansion coefficient and high hardness. Since silica has a low linear expansion coefficient and high hardness, the inorganic filler is preferably silica.

[0025] The inorganic filler is not limited to one type of inorganic material, but may be composed of multiple types of inorganic materials, for example, the inorganic material may include silica and calcium carbonate.

[0026] The silica may be spherical, amorphous, or a mixture of spherical and amorphous silica. Spherical silica is spherical or ellipsoidal silica. Spherical silica is produced, for example, by the flame fusion method. In the flame fusion method, natural silica or quartz is first pulverized into fine powder using a ball mill, and the pulverized material is sprayed into an LPG-oxygen flame. The sprayed individual particles melt and liquefy, and are then spheroidized by surface tension, resulting in spherical silica.

[0027] Irregular silica is polygonal silica, also called crushed silica. The surface of irregular silica has complex irregularities. Irregular silica may be crystalline irregular silica or fused irregular silica. Crystalline irregular silica is obtained by crushing natural silica and adjusting the crushed material to a predetermined particle size distribution. Fused irregular silica is obtained by melting natural silica and crushing it.

[0028] The silica is preferably spherical silica, which has a smaller specific surface area than amorphous silica, and therefore reduces the viscosity of the resin composition, making it easier to injection mold the resin composition.

[0029] Cumulative 100% particle size of inorganic filler D 100 The cumulative 100% particle diameter D of the inorganic filler is preferably 98.4 μm or less. 100 The cumulative 100% particle diameter D is more preferably 40.2 μm.100 is the particle size at which the cumulative small particle size is 100% in a volume-based cumulative particle size distribution curve. When polishing optical connection components, the abrasive penetrates into the base resin and comes into contact with the inorganic filler, thereby efficiently polishing the resin composition. If the particle size of the inorganic filler becomes large, the probability that the abrasive will come into contact with the inorganic filler decreases, and the polishing efficiency of the resin composition may decrease.

[0030] Cumulative 50% particle size D of inorganic filler 50 The cumulative 50% particle diameter D is preferably 1.4 μm or more and 16.0 μm or less. 50 is the particle size at which the cumulative small particle size reaches 50% in the cumulative particle size distribution curve based on volume. 50 If the cumulative 50% particle diameter D of the inorganic filler is larger than 16.0 μm, the linear expansion coefficient of the optical connecting part becomes non-uniform, and the dimensional accuracy of the optical connecting part may decrease. 50 If the thickness is less than 1.4 μm, the melt viscosity of the resin composition increases and the fluidity of the resin composition decreases, which can result in underfilling of the resin composition and sink marks in the optical connecting component, particularly when producing a thin optical connecting component.

[0031] The particle size of the inorganic filler is the equivalent sphere diameter. The particle size of the inorganic filler is measured by laser diffraction. For particle size measurement, a solvent is appropriately selected in which the particles are well dispersed without causing precipitation or aggregation. When the particles are silica, the solvent is, for example, water, alcohol, or a solvent containing a surfactant. Alternatively, the particles may be dispersed in the solvent by ultrasonic vibration.

[0032] The content of fibrous inorganic filler in the inorganic filler is preferably 0.01 wt% or less. It is even more preferable that the inorganic filler does not contain fibrous inorganic filler. The fibrous inorganic filler has a shape with a relatively large aspect ratio and a length of 10.6 μm or more. The fibrous inorganic filler cannot deform in accordance with the expansion and contraction of the surrounding base resin, increasing the anisotropy of the optical connecting component. When the content of fibrous inorganic filler having a length of 10.6 μm or more is less than 0.01 wt%, the effect of the fibrous inorganic filler can be ignored. Note that the content and length of the fibrous inorganic filler are the content in the form of pellets or optical connecting components. Because the fibrous inorganic filler is partially broken during kneading using the twin-screw kneading extruder described below, the content and length of the fibrous inorganic filler change before and after kneading.

[0033] This section explains how to measure the length of fibrous inorganic fillers. First, a pellet or optical connection component is heated to 700°C to completely incinerate it, preparing the sample. The sample is spread out on a tape used to fix the sample, ensuring that the sample particles do not overlap, and the sample is observed at 2000x magnification using a scanning electron microscope. Images of the sample are taken at three randomly selected locations, and the length of the fibrous inorganic filler in the captured images is measured.

[0034] [Manufacturing method] Next, a method for manufacturing a ferrule using the above-mentioned resin composition will be described. Fig. 2 is a flowchart showing a method for manufacturing a ferrule 10 according to this embodiment.

[0035] In step S101, a base resin, an inorganic filler, a colorant, a silane coupling agent, etc. are first mixed together. Then, the mixture is stirred using a Henschel mixer or the like, and then kneaded using a twin-screw kneading extruder or the like. In this way, a resin composition is produced.

[0036] In step S102, the resin composition is injected into a mold while being heated. After the resin composition is cooled, the ferrule 10 is removed from the mold.

[0037] [Action and effect] In this embodiment, the glass transition point of the base resin is 85°C or higher. Furthermore, the mass of the residue (heated residue) obtained by heating the resin composition at 700°C is 68.0% or more and 74.4% or less of the mass of the resin composition. Furthermore, the Rockwell hardness of the resin composition is 97.1 or more and 106.8 or less. This makes it possible to provide a resin composition that can both suppress loss fluctuation due to temperature rise and ensure good PC connection. The effects of this embodiment will be described in detail below, in comparison with the prior art.

[0038] Optical connection components such as MT ferrules are required to maintain stable connection characteristics even in high-temperature environments. For example, the international standard Telcordia GR-1435-CORE Issue 2 stipulates that the connection loss fluctuation of optical connection components in an uncontrolled environment equivalent to an outdoor environment at a high temperature of 85°C must be kept to 0.30 dB or less for standard and high-performance grades, and 0.20 dB or less for ultra-performance grades.

[0039] Such fluctuations in connection loss occur when the base resin expands due to a rise in temperature, causing the end face of the optical fiber inserted into the optical connecting part to shift in position. One possible technique for suppressing fluctuations in connection loss due to a rise in temperature is to add an inorganic filler to the base resin. The resin composition for optical connecting parts described in Patent Document 1 above contains 80 to 90% by weight of spherical silica microparticles, and reduces the connection loss of optical connecting parts due to a rise in temperature.

[0040] However, increasing the inorganic filler content can result in excessive rigidity of the optical connector, resulting in increased connection loss. Generally, the guide pin insertion holes in optical connectors have manufacturing variations of several micrometers, and optical connectors are connected by inserting guide pins into the guide pin insertion holes while the connectors deform moderately. At this time, a constant pressure is applied to the rear of the optical connector by a spring, ensuring proper PC connection between the optical fibers. If the optical connector is too hard, the resistance during guide pin insertion increases, reducing the pressure pressing the optical fibers together. This can prevent the end faces of the optical fibers from coming close enough to each other, resulting in poor PC connection between the optical fibers. In particular, in the case of multi-fiber ferrules, Fresnel reflection occurs due to gaps between the end faces of the optical fibers, which can significantly affect connection loss.

[0041] In light of the above, there has been a demand for a resin composition that can suppress loss fluctuations at high temperatures while also achieving good PC connections. Through extensive research, the inventors have discovered a resin composition that can suppress loss fluctuations at high temperatures while also achieving good PC connections, thanks to the following characteristic features:

[0042] First, the glass transition point of the base resin is 85°C or higher. This prevents the base resin from softening even in a high-temperature environment of 85°C, and suppresses fluctuations in connection loss of optical connecting components due to temperature rise.

[0043] Second, the mass of the residue obtained by heating the resin composition at 700°C is 68.0% or more and 74.4% or less of the mass of the resin composition. The composition of the resin composition differs before and after kneading. In particular, engineering plastics and super engineering plastics, which have high melting points, are generally composited with polymeric materials and inorganic materials using a twin-screw extruder. When the twin-screw extruder kneads the resin composition, significant shear heat is generated in the kneading section, causing the silane coupling agent of the resin composition, part of the base resin, or impurities in the resin composition to decompose or volatilize.

[0044] Third, the Rockwell hardness of the resin composition is 97.1 or more and 106.8 or less. The Rockwell hardness can be adjusted by changing the types and amounts of the base resin, inorganic filler, silane coupling agent, etc.

[0045] The following examples confirm that the above-described characteristic configuration can provide a resin composition that can suppress loss fluctuation due to temperature rise and achieve good PC connection at the same time.

[0046] [Example] Next, examples and comparative examples of the present invention will be described. First, the components of the resin compositions in the examples and comparative examples will be described. [Table 1]

[0047] Table 1 shows the base resin, inorganic filler, and silane coupling agent contained in the resin compositions according to the examples and comparative examples, and also shows whether or not calcium carbonate is contained in the inorganic filler.

[0048] In Examples 1 to 16 and Comparative Examples 1 to 25, the glass transition point of the base resin was 89°C, and the content of the base resin was 100 parts by weight. "PPS1" represents a linear polyphenylene sulfide resin (manufactured by DIC Corporation, melt viscosity 17 Pa s), and "PPS2" represents a semi-linear polyphenylene sulfide resin (manufactured by DIC Corporation, melt viscosity 30 Pa s).

[0049] The glass transition temperature of the base resin is measured according to JIS K-7121. First, pellets or ferrules are prepared from the resin composition using the method described below. The pellets or ferrules are then divided into pieces of a size that can fit into the measuring instrument, and the samples are prepared by adjusting them to standard conditions. The samples are then subjected to differential scanning calorimetry (DSC) at a heating rate of 10°C / min, and the midpoint glass transition temperature is measured as the glass transition temperature.

[0050] In addition, the melt viscosity of the base resin is measured based on JIS K-7210 under the conditions of a temperature of 300°C, a load of 20 kgf, and a die size of 1.0 mm x 10 mm.

[0051] In Examples 1 to 9, 15, and 16 and Comparative Examples 1 to 12 and 19 to 25, the inorganic filler was spherical silica (manufactured by Nippon Steel Chemical & Material Co., Ltd.). In Examples 10 and 11 and Comparative Examples 13 to 15, the inorganic filler was spherical silica (manufactured by Tatsumori Co., Ltd.). In Examples 12 to 14 and Comparative Examples 16 to 18, the inorganic filler was spherical silica (manufactured by Admatechs Co., Ltd.).

[0052] In Examples 1 to 16 and Comparative Examples 1 to 25, 2 parts by weight of furnace black (#7360 manufactured by Tokai Carbon Co., Ltd.) was added as a colorant.

[0053] Cumulative 100% particle size of inorganic filler D 100 and cumulative 50% particle diameter D 50 The measurement method for is as follows. First, a heating residue is obtained by the method described below. Next, the heating residue is finely crushed so as not to destroy the inorganic filler to obtain a sample. Then, the spherical equivalent diameter of the inorganic filler in the sample is measured in a wet state using a laser diffraction particle size distribution analyzer PSA 1190 (manufactured by Anton Paar), and the cumulative 100% particle diameter D 100 and cumulative 50% particle diameter D 50 For wet measurements, water is used as a solvent and ultrasound is used during the measurement.

[0054] The "addition rate" of the inorganic filler is expressed as a weight percentage relative to the entire resin composition.

[0055] In Examples 1 to 16 and Comparative Examples 1 to 25, the resin compositions were dry-treated with a liquid silane coupling agent. The content of the silane coupling agent was 3 parts by weight. "SC1" is a vinyl-based silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd.). "SC2" is an amino-based silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0056] In Comparative Examples 22 and 23, needle-shaped soft calcium carbonate (manufactured by Maruo Calcium Co., Ltd.) was added to the resin composition. In Examples 1 to 16 and Comparative Examples 1 to 21, 24, and 25, calcium carbonate was not added to the resin composition. Calcium carbonate was added so that the weight ratio of silica to calcium carbonate was 8:2. The maximum length, average length, and average diameter of the needle-shaped soft calcium carbonate before kneading with the resin composition were 25 μm, 10 μm, and 2 μm, respectively. Furthermore, the maximum length of the needle-shaped soft calcium carbonate after kneading with the resin composition was 10.6 μm.

[0057] The method for measuring the length of a fibrous inorganic filler is explained below. First, a heating residue is obtained using the method described below. At three randomly selected locations, the heating residue is observed at 2000x magnification using a scanning electron microscope, and the lengths of particles having a fibrous or needle-like shape are measured.

[0058] Next, the experimental results for the pellets and ferrules made from the resin compositions of the examples and comparative examples are as follows: The ferrules in the examples and comparative examples are 12-fiber MT ferrules. [Table 2]

[0059] Table 2 shows the inorganic filler addition rate, heating residue of pellets and ferrules, Rockwell hardness, change in connection loss due to temperature increase, evaluation of PC connection (Evaluation 1), evaluation of change in connection loss due to temperature increase (Evaluation 2), evaluation of polishability (Evaluation 3), and evaluation of appearance (Evaluation 4).

[0060] The methods for producing pellets and ferrules according to the examples and comparative examples are described below. First, the components in Table 1 are mixed, and then the resin composition is kneaded in a twin-screw extruder at 350°C and a screw rotation speed of 400 rpm to produce pellets. The pellets are then kneaded in an electric injection molding machine at a cylinder temperature of 320°C to 350°C, a mold temperature of 130°C to 160°C, and a holding pressure of 1000 to 1500 kgf / cm.2 A 12-fiber MT ferrule is produced by injection molding. The guide hole diameter of the ferrule is made to be 699.0 to 699.4 μm. The length of the perpendicular line drawn from the center of the fiber insertion hole to the central axis of the guide pin insertion hole is adjusted to be 0 to 0.5 μm, and the length of at least one fiber insertion hole is adjusted to be 0.45 to 0.5 μm.

[0061] The method for measuring the heating residue is explained below. First, 3 mg of sample is prepared by crushing pellets or ferrules. Using a thermogravimetric analyzer (Mettler-Toledo), the sample is heated from room temperature to 700°C at a rate of 10°C / min in an oxygen flow of 200 ml / min. Five tests are conducted for each example and comparative example. The weight at 700°C is then divided by the weight at room temperature, and the average value expressed as a percentage is calculated as the heating residue.

[0062] Next, the Rockwell hardness measurement method will be described. First, pellets or ferrules are compression-molded at a temperature of 350°C and a pressure of 1 MPa to prepare 4 mm x 10 mm x 80 mm test specimens. The molding temperature is preferably between 300°C and 400°C, and the pressure during compression molding is preferably between the contact pressure of the press and 10 MPa. Vacuuming is used as necessary to adjust the pressure. Next, based on JIS 7202-2, the test is performed at room temperature under the conditions of hardness scale M, standard load 98.07 N, test load 980.7 N, and steel ball indenter 6.35 mm. The indenter is pressed into five points on the center of the 10 mm x 80 mm surface of the test specimen, two points approximately 10 mm from the center, and two points approximately 20 mm from the center on both sides of the long side of the test specimen, and the average value is calculated. During the test, the test specimen is pressed so as not to leave any indentation marks on the surface opposite the surface on which the test specimen is placed. Before compression molding, the ferrule is crushed with a hammer using a force that does not change the shape of the inorganic filler. At this time, care is taken not to crush the ferrule into small pieces so that the shape of the inorganic filler changes. Furthermore, compression molding is performed so that there are no bubbles larger than 1 mm in diameter inside the test piece. Bubbles are confirmed by observing the inside of the test piece using X-ray CT.

[0063] Next, we will explain the method for measuring loss fluctuation. First, 15 pairs of MPO connectors are assembled using ferrules from the example and comparative examples. Next, 12 optical fibers are spliced ​​into each MPO connector, and the connectors are placed in a thermostatic chamber to measure the connection loss of 180 optical fibers. First, the connection loss is measured when the thermostatic chamber is at room temperature. Next, the temperature is raised to 85°C and maintained at that temperature for 168 hours, and the maximum connection loss during that time is measured. The difference between the maximum connection loss at 85°C and the connection loss at room temperature is calculated as the loss fluctuation. The connection loss is measured at a wavelength of 1.31 μm.

[0064] If the splice loss of all optical fibers out of the 180 optical fibers is less than 1 dB at room temperature, the rating is rated as good (OK). If the splice loss of one or more optical fibers out of the 180 optical fibers is 1 dB or more, the rating is rated as poor (NG).

[0065] If the loss variation in Table 2 is 0 dB or more and less than 0.2 dB, then Rating 2 is evaluated as good (A). If the loss variation in Table 2 is 0.2 dB or more and less than 0.3 dB, then Rating 2 is evaluated as good (B). If the loss variation in Table 2 is 0.3 dB or more, then Rating 2 is evaluated as poor (C). Note that if Rating 1 is poor (NG), then Rating 2 is omitted.

[0066] The evaluation method for Grade 3 is as follows. First, 12 optical fibers are inserted into a ferrule and fixed with an epoxy resin adhesive. Next, the optical fibers protruding from the end face of the ferrule and the epoxy resin adhesive adhering to the end face of the ferrule are removed using 2000-grit waterproof abrasive paper coated with silicon carbide abrasive grains. Water is then dripped onto a lapping film coated with 15 μm silicon carbide abrasive grains, and the ferrule is polished for 1 minute using an MT ferrule polisher (manufactured by Domaille). Water is then dripped onto a lapping film coated with 3 μm silicon carbide grains, and the polishing time until the average protrusion length of the 12 fibers reaches 2 μm is measured. If the polishing time is less than 1 minute, Grade 3 is evaluated as good (A). If the polishing time is between 1 and 2 minutes, Grade 3 is evaluated as good (B). If the polishing time is 2 minutes or more, Grade 3 is evaluated as poor (C).

[0067] The appearance of the ferrule is observed, and if there are no sink marks or unfilled areas in the ferrule, the rating is 4, which is good (OK). If there are sink marks or unfilled areas in the ferrule, the rating is 4, which is poor (NG).

[0068] As described above, according to the present invention, it is possible to provide an optical connecting part that can suppress loss fluctuations due to temperature rise and achieve good PC connection at the same time.

[0069] In addition, as the content of the inorganic filler increases, the hardness of the optical connecting parts also increases, and the polishing efficiency of the optical connecting parts decreases. Therefore, it may be difficult to simultaneously suppress the loss fluctuation due to temperature rise and improve the polishing efficiency. In the present invention, the cumulative 100% particle diameter D of the inorganic filler 100 The cumulative 100% particle diameter D of the inorganic filler is preferably 98.4 μm or less. 100 It is more preferable that the polishing efficiency is 40.2 μm. This makes it possible to obtain a resin composition that not only suppresses loss fluctuation due to temperature rise and achieves good PC connection, but also improves polishing efficiency.

[0070] The present invention is not limited to the above-described embodiments and can be modified in various ways. Furthermore, for parts not specifically described or illustrated in the embodiments, well-known and publicly known techniques in the relevant technical field can be applied as appropriate. For example, the guide pin insertion hole diameter of the ferrules in the examples and comparative examples is 700 μm, but similar results can be obtained even if the guide pin insertion hole is 550 μm or other sizes. Furthermore, the ferrules in the examples and comparative examples are 12-fiber MT ferrules, but similar results can be obtained even if the ferrules have multiple fiber hole position arrangements, such as 12 fibers x 2 rows. Furthermore, the present invention is not limited to MT ferrules with standard dimensions, but can also be applied to optical connecting components that use the same positioning principles as MT ferrules. [Explanation of symbols]

[0071] 10 ferrules 12 Optical fiber insertion hole 14 Optical fiber core 16 Optical Fiber 18 End face 20 Guide pin insertion hole 22 Guide pin

Claims

1. A base resin; A resin composition for optical connecting parts containing an inorganic filler, The glass transition temperature of the base resin is 85°C or higher, the mass of a residue obtained by heating the resin composition for optical connecting parts at 700°C is 68.0% or more and 74.4% or less of the mass of the resin composition for optical connecting parts, The resin composition for optical connecting parts has a Rockwell hardness of 97.1 or more and 106.8 or less.

2. 2. The resin composition for optical connecting parts according to claim 1, wherein the base resin is a thermoplastic crystalline polymer.

3. 2. The resin composition for optical connecting parts according to claim 1, wherein the base resin is polyarylene sulfide.

4. 2. The resin composition for optical connecting parts according to claim 1, wherein the base resin is polyphenylene sulfide.

5. 2. The resin composition for optical connecting parts according to claim 1, wherein the inorganic filler is silica.

6. The cumulative 100% particle diameter D of the inorganic filler １００ The resin composition for optical connecting parts according to claim 1, wherein the average particle diameter is 98.4 μm or less.

7. The cumulative 100% particle diameter D of the inorganic filler １００ The resin composition for optical connecting parts according to claim 1, wherein the thickness is 40.2 μm or less.

8. 2. The resin composition for optical connecting parts according to claim 1, wherein the content of silica in said inorganic filler is 99.99 wt % or more.

9. 2. The resin composition for optical connecting parts according to claim 1, wherein the content of fibrous inorganic filler having a length of 10.6 [mu]m or more in said inorganic filler is 0.01 wt% or less.

10. An MT ferrule comprising the resin composition for optical connecting parts according to any one of claims 1 to 9.

11. a first step of kneading a base resin and an inorganic filler; a second step of injection-molding the mixture obtained by the first step, The glass transition temperature of the base resin is 85°C or higher, the mass of a residue obtained by heating the resin composition for optical connecting parts at 700°C is 68.0% or more and 74.4% or less of the mass of the resin composition for optical connecting parts, The method for producing a resin composition for optical connecting parts, wherein the resin composition for optical connecting parts has a Rockwell hardness of 97.1 or more and 106.8 or less.

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