Resin component and vehicle lamp

Abstract

Provided are: a resin component that includes a filler capable of improving physical properties in addition to an extender effect; and a vehicle lamp that uses the resin component. The present invention is a resin component including a thermoplastic resin and a filler that is a shell powder having a particle size of 5-100 μm. The vehicle lamp comprises a lamp chamber, a light source provided in the lamp chamber, and the resin component.

Description

Resin parts and vehicle lighting fixtures

[0001] This invention relates to resin parts and vehicle lighting fixtures.

[0002] Various fillers are added to resin parts depending on their function and application. For example, it is known that resin parts that serve as housing components for vehicle lighting fixtures use resin materials that are mainly composed of polypropylene and contain inorganic fillers such as talc and white pigments. Examples of inorganic fillers include talc, glass fiber, calcium carbonate, mica, and wollastonite (see, for example, Patent Document 1).

[0003] International Publication No. 2023 / 189746

[0004] When calcium carbonate particles are used as a filler, the amount of resin used in the resin part can be relatively reduced (a volume-increasing effect), which has the advantage of lowering costs. On the other hand, using plate-shaped fillers such as talc or rod-shaped fillers such as glass fiber can improve the physical properties of the resin part, such as strength and rigidity.

[0005] The present invention aims to provide a resin part containing calcium carbonate particle filler that can enhance physical properties in addition to increasing volume, and a vehicle lighting fixture using the same.

[0006] A resin component according to one aspect of the present invention is characterized by comprising a thermoplastic resin and a filler which is seashell powder with a particle size of 5 μm to 100 μm.

[0007] According to the present invention, by using a filler made of seashell powder with a particle size of 5 μm to 100 μm, it is possible to increase the volume and improve the physical properties of resin parts. Furthermore, since discarded seashells can be used, the cost can be reduced compared to cases where calcium carbonate mineral is used as a raw material. In addition, seashells absorb CO2 from water during their growth process. ２ By using seashell powder as a filler, CO2 is absorbed and used to create a calcium carbonate shell within the resin part. ２ It can be fixed in place. Furthermore, it can prevent environmental problems such as soil contamination caused by the disposal of seashells.

[0008] This is a diagram showing vehicle lighting fixtures.

[0009] Embodiments of the present invention will be described in detail below. The resin part of this embodiment includes a thermoplastic resin and a filler.

[0010] Examples of thermoplastic resins that can be used include polyethylene, polypropylene, polyester, polystyrene, and polyamide. Among these, polypropylene is preferred. Polypropylene can be homopolymer, copolymer, block polymer, or random polymer, but polypropylene composed of homopolymer and copolymer is preferred. The melt flow rate (MFR) of the polypropylene when extruded at 230°C with a pressure of 21N is preferably 10 g / 10 min to 60 g / 10 min. Resin parts containing polypropylene with such properties have a lower specific gravity and higher fluidity compared to polycarbonate, making it easier to mold complex shapes and large resin parts, and also allowing for lightweight construction.

[0011] Fillers, when added to resin parts, relatively reduce the amount of resin constituting the resin part and improve the strength, rigidity, and heat resistance of the resin part. In this embodiment, the filler is seashell powder with a particle size of 5 μm to 100 μm. The filler in this embodiment can be obtained, for example, by crushing seashells using a pulverizer to a particle size of 5 μm to 100 μm. The particle size of the seashell powder is preferably 20 μm to 50 μm, and more preferably 10 μm to 50 μm. Here, the particle size of each seashell powder is the equivalent diameter of a circle when the seashell powder is viewed from one direction. If the particle size of the filler is larger than 100 μm, the filler will be prone to cracking. In addition, it may have effects such as roughening the surface shape of the resin part or poor fluidity of the resin material during molding of the resin part. It is preferable that the median diameter D50 of the volume-based particle size of the filler is within the above range. A sharp particle size distribution is preferable, but it may also be broad.

[0012] In this embodiment, the filler preferably contains 40% or more plate-shaped particles and / or columnar particles, and more preferably 60% or more. By using a filler containing 40% or more plate-shaped particles and / or columnar particles, the physical properties of the resin part, such as strength and rigidity, can be improved. Here, plate-shaped particles are particles whose major axis diameter l, minor axis diameter b, and thickness t (l≧b≧t) satisfy b / t≧1.5 and l / b<2. Columnar particles are particles that satisfy l / b≧2. Note that the major axis l, minor axis b, and thickness t are triaxial diameters. In triaxial diameters, the lengths of the three sides of the longest rectangular parallelepiped circumscribed around a single particle are defined in order from longest to shortest as major axis l, minor axis b, and thickness t (l≧b≧t).

[0013] The filler of this embodiment can be obtained by crushing the above-mentioned seashells into pieces of about a few centimeters square, then calcining them at, for example, 200°C to 400°C for 0.5 to 3 hours, and further pulverizing them to the particle size range described above. For pulverization, for example, a roll mill or hammer can be used. At that time, organic substances such as chitin may be removed using an organic solvent such as acetone, ethanol, or hexane. Alternatively, surface impurities may be removed using an aqueous sodium hydroxide solution.

[0014] As for seashells, those that are readily available as by-products of fisheries and are rich in calcium carbonate can be used. For example, seashells such as scallop shells, oyster shells, pearl oyster shells, clam shells, mussel shells, turban shell shells, abalone shells, and sea urchin shells, which are by-products of fisheries, can be used. These seashells have a prismatic layer. The prismatic layer contains calcium carbonate (calcite) with a trigonal crystal structure. The powder obtained by crushing the prismatic layer is preferable because it yields columnar particles. On the other hand, seashells with a nacreous layer, such as pearl oyster shells and abalone shells, have a two-layer structure with a prismatic layer on the outside and a nacreous layer on the inside. The nacreous layer contains calcium carbonate (aragonite) with an orthorhombic crystal structure. Crushing the nacreous layer yields a plate-like powder, which is preferable. When pearl oyster shells and abalone shells, which have a nacreous layer, are powdered, a filler is obtained that is a mixture of columnar powder derived from the prismatic layer containing calcite and plate-like powder derived from the nacreous layer containing aragonite. The resulting filler is a mixture of columnar powder derived from calcite and plate-like powder derived from aragonite. By adjusting the ratio of this columnar powder to plate-like powder, it is possible to adjust not only the volume-increasing effect but also the effect of improving the physical properties of resin parts.

[0015] In the resin parts of this embodiment, the proportion of filler is preferably 20% to 40% by mass, and more preferably 25% to 35% by mass. If the proportion of filler is less than 20% by mass, the volume-increasing effect of the filler will be diminished. On the other hand, if the proportion of filler exceeds 40%, there is an excess of filler, which may impair the physical properties of the resin parts.

[0016] The resin parts of this embodiment can be used in vehicle lighting fixtures. Figure 1 is a cross-sectional view showing an example of a vehicle lighting fixture. As shown in Figure 1, the vehicle lighting fixture 1 includes a lamp body 22, an outer cover 24, a light source unit 10 (light source), etc. The lamp body 22 and the outer cover 24 form a lamp chamber 26.

[0017] The vehicle light fixture 1 comprises one or more light source units 10 and an extension 15 within a light chamber 26. The light source unit 10 includes a light source 11, a reflector 12, and a light source base 13. Light emitted from the light source 11 is reflected by the reflector 12, passes through the outer cover 24, and is emitted in front of the vehicle light fixture 1. The light source 11 and the reflector 12 are attached to the light source base 13. The extension 15 is a decorative component that prevents the internal components of the vehicle light fixture 1 from being visible from the outside.

[0018] The light source unit 10 is attached to the aiming mechanism 20 via a bracket 14. The aiming mechanism 20 is attached to the lamp body 22. The aiming mechanism 20 has the function of adjusting the direction of the optical axis of the light source unit 10 within the lamp chamber 26.

[0019] The resin parts of the above-described embodiment can be used in the vehicle lighting fixture 1. For example, by molding the resin parts of the above-described embodiment, a reflector 12, a bracket 14, and a lamp body 22 can be manufactured and used in the vehicle lighting fixture 1. The surface of the resin parts of this embodiment is smooth and is suitable for use in reflectors 12 which are coated with metal vapor deposition, and extensions 15 which are visible from the outside. Furthermore, since the resin parts of this embodiment are lightweight, they are suitable for use in large parts such as the lamp body 22. Moreover, since the resin parts of this embodiment have high rigidity, they are suitable for use in brackets 14 and lamp bodies 22.

[0020] The vehicle lighting device 1 is not particularly limited and may be, for example, a car's headlights, fog lights, position lights, rear combination lights, turn signal lights, or various lights that inform pedestrians or drivers of other vehicles of the status of their vehicle (for example, that it is in autonomous driving mode).

[0021] [Example 1] Scallop shells were crushed into pieces of about a few centimeters square, then calcined at 300°C for about 2 hours, and further crushed in a roll mill to obtain filler, which is shell powder with an average particle size of 20 μm. The obtained filler was observed with an electron microscope, and the triaxial diameter (major axis l, minor axis b, and thickness t) of filler particles with a length of 5 μm or more on any side in the field of view was measured. The number of plate-like particles satisfying b / t ≥ 1.5 and l / b < 2, columnar particles satisfying l / b ≥ 2, and particles that are neither plate-like nor columnar (particles satisfying l / b < 2 and b / t < 1.5) was counted. The total proportion of plate-like and columnar particles in the obtained filler particles was 67%.

[0022] Polypropylene (BC03C, manufactured by Nippon Polypropylene Co., Ltd.) was used as the base resin, and the above-mentioned filler particles were kneaded with the base resin to obtain a resin material in an amount of 30% by mass of the total.

[0023] [Example 2] Filler was obtained in the same manner as in Example 2, except that oyster shells were used instead of scallop shells. The obtained filler was observed with an electron microscope, and the triaxial diameter of filler particles with a length of 5 μm or more on any side in the field of view was measured. The number of plate-like particles satisfying b / t ≥ 1.5 and l / b < 2, columnar particles satisfying l / b ≥ 2, and particles that are neither plate-like nor columnar (particles satisfying l / b < 2 and b / t < 1.5) was counted. The total proportion of plate-like and columnar particles in the obtained filler particles was 62%. Polypropylene (BC03C, manufactured by Nippon Polypropylene Co., Ltd.) was used as the base resin, and the above filler particles were kneaded with the base resin to obtain a resin material in an amount of 30% by mass of the total.

[0024] [Comparative Example 1] Polypropylene (BC03C, manufactured by Nippon Polypropylene Co., Ltd.) was used as the base resin, and commercially available calcium carbonate derived from a mineral (limestone) with an average particle size of 2 μm was used as a filler. The mixture was kneaded with the base resin to obtain a resin material in an amount of 30% by mass.

[0025] [Comparative Example 2] Polypropylene (BC03C manufactured by Nippon Polypropylene Co., Ltd.) was used as the base resin, and the resin material was prepared without using fillers.

[0026] The physical properties of the test pieces (resin parts) formed from the resin materials of Example 1, Example 2, Comparative Example 1, and Comparative Example 2 were measured by the following method. [Flexural modulus of elasticity] A flexure test was conducted in accordance with the provisions of JIS K7171:2016 to measure the flexural modulus of elasticity and flexural strength. The obtained resin material was formed into a test piece with a width b = 10 mm, a thickness h = 4 mm, and a length of 80 mm. This test piece was placed between supports at a distance L = 6.4 cm, and in an environment of 25°C, the load P and deflection w when the central part of the test piece was pressed by a plunger at a test speed of 5 mm / min were measured, and the stress σ and strain ε were calculated. Here, σ = 3PL / 2bh ２ and ε = 6hw / L ２ is. The strain ε １ = 0.05% deflection w １ when the load P applied to the measuring instrument １ from the stress σ １ = 3P １ L / 2bh ２ is calculated, and the strain ε ２ = 0.25% deflection w ２ when the load P applied to the measuring instrument ２ from the stress σ ２ = 3P ２ L / 2bh ２ is calculated. The flexural modulus of elasticity E can be calculated from the obtained values as follows. E = (σ ２ - σ １ ) / (ε ２ - ε １ )

[0027] [Flexural strength] During the above flexure test, the maximum flexural stress that the test piece can withstand is defined as the flexural strength.

[0028] [Tensile strength] A tensile test was conducted in accordance with the provisions of JIS K7161-1:2014 to perform a tensile strength test. The obtained resin material was formed into a dumbbell-shaped tensile test piece with a total length l ３ [[ID=4〕]= 170 mm, a length of the parallel part l １ = 80 mm, a width b of the central parallel part １ = 10 mm, and a thickness h = 4 mm. Markings are provided on the parallel parts at intervals of 75 mm (distance between markings L ０(= 75 mm). Attach this test piece to the grips of a tensile strength testing machine with a grip spacing L = 115 mm. Measure the stress while pulling the test piece at a speed of 200 mm per minute, and take the first maximum stress as the tensile strength.

[0029] [Heat Deflection Temperature under Load] Measure the heat deflection temperature (flatwise) in accordance with the provisions of JIS K7191-2:2015. Mold the obtained resin material to create a test piece with a width b = 10 mm, a thickness h = 4 mm, and a length of 80 mm. Place this test piece across the supports with a distance L = 6.4 cm in an oil bath, and while pressing the central part of the test piece with a punch at 1.80 MPa, raise the temperature of the oil bath at a rate of 120 °C / h. The temperature when the deflection w of the test piece reaches the specified deflection Δs (mm) is defined as the heat deflection temperature under load. Here, the specified deflection Δs is expressed by the following formula. Δs = L ２ Δε ｆ / 600h Here, Δε ｆ is the bending strain increment (%). The results are shown in Table 1.

[0030]

[0031] As shown in Table 1, when using scallop shells or oyster shells as fillers, physical properties such as flexural strength, flexural modulus, tensile strength, and heat deflection temperature under load can be improved compared to the case of using a conventional calcium carbonate filler.

[0032] As described above, the embodiments of the present invention have been explained, but it is needless to say that the technical scope of the present invention should not be construed in a limited manner by the description of this embodiment. This embodiment is merely an example, and it is understood by those skilled in the art that various modifications of the embodiments are possible within the scope of the invention described in the claims. The technical scope of the present invention should be determined based on the scope of the invention described in the claims and its equivalent scope.

[0033] This application claims priority based on Japanese Patent Application No. 2024-228312 filed on December 25, 2024, the content of which is incorporated herein by reference.

Claims

1. A resin part comprising a thermoplastic resin and a filler consisting of seashell powder with a particle size of 5 μm to 100 μm.

2. The resin part according to claim 1, wherein the seashell powder contains 40% or more plate-shaped and / or columnar particles.

3. The resin part according to claim 1 or 2, wherein the shell powder is powder from any of the following: scallop shells, oyster shells, pearl oyster shells, clam shells, mussel shells, or turban shell shells.

4. The resin part according to any one of claims 1 to 3, wherein the proportion of the seashell powder is 20% by mass to 40% by mass.

5. A vehicle light fixture comprising a light source and a resin component according to any one of claims 1 to 4.

6. The vehicle lamp according to claim 5, comprising a lamp body made of the resin parts and an outer cover.

7. The vehicle lighting device according to claim 5, comprising the resin component and a reflector that reflects light from the light source.

8. The vehicle lighting fixture according to claim 5, comprising a bracket made of the resin component that supports the light source.

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