JP2013055001A - Reflector for vehicular lamp and vehicular lamp including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflector for a vehicular lamp, by a molded component using a BMC resin as a molding material, capable of obtaining lighter weight while securing excellent mechanical strength as an injection molded component used for a reflector for a vehicular lamp and moreover suppressing scratches and abrasion on an inner wall of a cavity to be caused at the time of injection molding to the cavity.SOLUTION: In the BMC resin made of a matrix resin having unsaturated polyester resin as a principal component added with at least glass fiber, calcium carbonate 62 and glass hollow beads 61 as inorganic fillers, a mass ratio of calcium carbonate 62 to the BMC resin is set to be in a range of 19.7% to 10.6 vol% and moreover the mass ratio of the glass hollow beads 61 to the BMC resin is set so that a total mass ratio of the mass ratios of calcium carbonate 62 and the glass hollow beads 61 to the BMC resin may be in a range of about 49 vol%.

Description

  The present invention relates to a reflector that includes a light reflecting surface that constitutes a vehicular lamp and reflects light emitted from a light source toward a front front lens, and a vehicular lamp that includes the reflector.

  This type of reflector used for vehicle lamps is an inorganic filler made of calcium carbonate or the like in a matrix resin mainly composed of an unsaturated polyester resin when molding a molded product before forming a light reflecting surface by injection molding. BMC material (bulk molding compound) to which glass fiber or glass balloon is added may be used as a molding material.

As a specific example of using a BMC material as an injection molding material, for example, an inorganic filler (for example, calcium carbonate) having an average particle diameter of 0.5 μm or more with respect to 100 parts by mass of an unsaturated polyester resin and a crosslinking agent. 40 to 210 parts by mass and 30 to 160 parts by mass of a hollow filler (for example, glass balloon) having a pressure strength of 2100 × 10 ⁴ N / m ² , and the mass ratio of the inorganic filler to the hollow filler is 2: 8 to It is added within a range of 8: 2 (see, for example, Patent Document 1).

Japanese Patent No. 4673298

  By the way, in the BMC material having the above composition, the hollow filler having a predetermined pressure strength is added to the matrix resin composed of the unsaturated polyester resin and the crosslinking agent from the viewpoint of reducing the weight of the reflector as described above. The addition amount is set in a range in which various properties such as moldability, dimensional stability of the molded body, and rigidity can be secured satisfactorily.

  At the same time, the matrix resin contains, for example, chopped strand glass cut to a fiber length of about 1.5 to 25 mm as a fiber reinforcement, and calcium carbonate as an inorganic filler. When the BMC material is injected into the cavity, the cavity wall surface may be damaged and worn due to the aggressiveness of the fiber reinforcement and the irregular shape of the calcium carbonate particles. Will lead to a decrease in the degree of completion.

  Therefore, the present invention was devised in view of the above-mentioned problems, and its object is to reduce the weight and to damage and wear the cavity wall surface caused by injection into the cavity of the molding die during injection molding. An object of the present invention is to provide a reflector for a vehicle lamp using a molded body that uses a BMC material that suppresses the above as a molding material.

  In order to solve the above-mentioned problems, the invention described in claim 1 of the present invention includes a matrix resin containing an unsaturated polyester resin as a main component, calcium carbonate as an inorganic filler, a fiber reinforcement, and glass hollow beads. A reflector for a vehicle lamp using an injection-molded product of an added BMC resin, wherein the calcium carbonate has a volume ratio of 19.7 to 10.6 vol% with respect to the BMC resin, and the glass hollow beads are The total volume ratio of the volume ratio of the calcium carbonate to the BMC resin and the volume ratio of the glass hollow beads is in a range that is about 49 vol%.

  Further, the invention described in claim 2 of the present invention is that in claim 1, the injection-molded product is such that the BMC resin is inserted through a gate from a direction substantially perpendicular to the surface direction of the cavity of the injection mold. It is characterized by being injected into the cavity and molded.

  In the BMC resin in which at least glass fiber, calcium carbonate, and glass hollow beads are added as inorganic fillers to a matrix resin containing an unsaturated polyester resin as a main component, the volume ratio of calcium carbonate to BMC resin is 19.7 to The volume ratio of the glass hollow beads to the BMC resin is set to a range such that the total volume ratio of the volume ratio of calcium carbonate to the BMC resin and the volume ratio of the glass hollow beads is about 49 vol%. did.

  As a result, it is possible to reduce the weight while securing a good mechanical strength as an injection molded product used for a reflector of a vehicle lamp, and to prevent damage and wear on the inner wall of the cavity caused by injection into the cavity during injection molding. The reflector of the vehicle lamp by the molded article which used BMC resin to suppress as a molding material was able to be realized.

It is longitudinal section explanatory drawing which shows an example of the vehicle lamp using the reflector of embodiment. It is the A section enlarged explanatory view of FIG. It is explanatory drawing of a metal mold apparatus. It is a figure explaining a trial manufacture sample. It is a figure explaining the shape of the additive of BMC resin. It is a partial expanded explanatory view of a metal mold apparatus. Similarly, it is the elements on larger scale of a metallic mold device. Similarly, it is the elements on larger scale of a metallic mold device.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. 1 to 8 (the same portions are given the same reference numerals). The embodiments described below are preferable specific examples of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention particularly limits the present invention in the following description. Unless stated to the effect, the present invention is not limited to these embodiments.

  Drawing 1 is a longitudinal section explanatory view showing an example of a vehicular lamp using a reflector of an embodiment.

  A vehicular lamp 1 includes a housing 2 having an opening and a seal cover mounting hole on opposite sides, a front lens 3 attached to the opening of the housing 2 so as to close the opening of the housing 2, and a seal cover mounting A lamp chamber 5 comprising a sealed space is formed with the seal cover 4 mounted in the seal cover mounting hole so as to close the hole.

  A reflector 6 having a concave curved shape that is supported and fixed to the housing 2 and that opens toward the front lens 3 is accommodated in the lamp chamber 5, and is inserted into a valve insertion hole of the seal cover 4 to be a valve of the reflector 6. A bulb (light source) 7 inserted into the insertion hole is arranged in a state of being surrounded by the reflector 6 on the side.

  The reflector 6 has a plurality of curved surfaces or flat surfaces having different shapes on the surface (inner surface) surrounding the valve 7 from the side of a molded product (molded base material of the reflector 6) obtained by injection molding of BMC resin. And a composite surface 8 composed of a combination of curved surfaces.

  An undercoat layer 9 made of resin is formed on the composite surface 8 of the molding substrate 13 as shown in FIG. 2 (a diagram illustrating the configuration of the composite reflection surface in the enlarged view of the portion A in FIG. 1). A metal reflective film 10 such as aluminum is formed thereon by vapor deposition or sputtering, and a top coat layer 11 made of a transparent resin is further formed thereon, contributing to improvement in light reflection efficiency and formation of a light distribution pattern. A composite reflecting surface 12 is formed.

  That is, each reflecting surface constituting the composite reflecting surface 12 has an optimum shape so that the reflected light becomes an irradiation light that reflects light emitted from the light source 7 and forms the desired region in the light distribution pattern. Is set.

  Therefore, returning to FIG. 1, in the vehicular lamp 1 having the above-described configuration, the light is emitted from the light emitting portion 14 of the bulb 7 toward the composite reflecting surface 12a above the horizontal plane of the reflector 6 including the optical axis X of the bulb 7. The light L1 and the light L2 emitted toward the lower composite reflection surface 12b are reflected by the composite reflection surfaces 12a and 12b, respectively, and the reflected light whose light distribution has been controlled is located in front and forms a light distribution pattern. The light passes through a so-called plain front lens 3 that does not contribute to the light and is irradiated forward, and the irradiated light forms a desired light distribution pattern.

  Next, in the reflector 6 having such an optical function, a BMC resin that is a molding material for injection molding that molds a molded product (molded substrate) that is a base material on which the composite reflecting surface 12 is provided will be described.

  BMC resin is a thermosetting resin. As a basic composition, glass fiber is added to the matrix resin as a fiber reinforcing material, calcium carbonate, glass hollow beads, etc. are added as inorganic fillers, and further a curing agent, a release agent, etc. Is added.

  Among them, the matrix resin is mainly composed of an unsaturated polyester resin, and the type of the unsaturated polyester resin is not particularly limited. For example, it can be obtained by polycondensation of a polyhydric alcohol and an unsaturated polybasic acid. It is what was done.

  The type of polyhydric alcohol is not particularly limited. For example, ethylene glycol, propylene glycol, neopentyl glycol, butanediol, diethylene glycol, dipropylene glycol, triethylene glycol, pentanediol, hexanediol, neo Pentanediol, hydrogenated bisphenol A, bisphenol A, glycerin and the like can be used.

  Among these, propylene glycol, neopentyl glycol, and bisphenol A or hydrogenated bisphenol A are preferable from the viewpoints of heat resistance, mechanical strength, moldability, and the like.

  The type of unsaturated polybasic acid is not particularly limited. For example, maleic anhydride, fumaric acid, citraconic acid, itaconic acid and the like can be used.

  Among these, maleic anhydride and fumaric acid are preferable from the viewpoints of heat resistance, mechanical strength, moldability, and the like.

  As the fiber reinforcement, glass fibers having a fiber length of about 1.5 to 25 mm can be used. In addition, organic and inorganic fibers such as pulp fiber, tetron fiber, vinylon fiber, carbon fiber, aramid fiber, and wollastonite can also be used.

  Next, the verification result of the prototype molded substrate obtained by injection molding using the mold apparatus of FIG. 3 will be described with respect to the optimal composition ratio (volume ratio: vol%) of the BMC resin composition.

  First, the mold apparatus shown in FIG. 3 (description of the mold apparatus) has a butt surface at the position shown in the figure by clamping the fixed mold (cavity mold) 20 and the movable mold (core mold) 30. A cavity 50 for forming an injection-molded product is defined by the fixed mold 20 and the movable mold 30 which are clamped and have 40 (hereinafter referred to as a parting surface).

  The fixed mold 20 has a fan gate 21 for injecting a BMC resin, which is a molding resin, into the cavity 50, extending in a direction substantially perpendicular to the mold opening direction A of the movable mold 30. The fan gate 21 communicates with the nozzle contact portion 25 of the sprue bush 24 via the runner 22 and the sprue 23.

  Then, when BMC resin is injected into the sprue 23 from the nozzle tip portion in a state where the nozzle tip portion (not shown) of the injection molding machine is in contact with the nozzle contact portion 25 of the sprue bush 24, the BMC resin is sprue 23. Is injected into the cavity 50 through the runner 22 and the fan gate 21, and the entire cavity 50 is filled with BMC resin. Thereafter, the BMC resin in the cavity 50 is heated and cured to obtain an injection molded product.

  Therefore, a prototype sample of a reflector molding base material made of five types of BMC resins having different compositions as shown in FIG. 4 (a table for explaining the prototype sample) was produced by injection molding using the mold apparatus.

  Sample 1 has a volume ratio of a matrix resin having a specific gravity of 1.1 to a BMC resin of 42.2 vol%, a volume ratio of glass fibers having a specific gravity of 2.7, 8.8 vol%, and a volume ratio of calcium carbonate having a specific gravity of 2.7. The volume ratio of glass hollow beads of 49.1 vol% and specific gravity 0.6 was 0 vol%. At this time, the specific gravity of the BMC resin was 2.0.

  Further, as the glass hollow beads 61, glass bubbles (trademark) S60HS (manufactured by 3M company) which is a true sphere having a pressure strength of 100 MPa or more is used, and a glass fiber having a fiber length of about 2.5 mm is used as a fiber reinforcement. As the calcium carbonate 62, a non-spherical body (pulverized product) was used (see FIG. 5 (a diagram showing the shape of glass hollow beads and calcium carbonate)).

  When injection molding was performed using BMC resin added with S60J having a pressure strength lower than that of S60HS of Glass Bubbles (less than 100 MPa), the glass hollow beads were crushed and the weight of the molded product was increased. . For this reason, the glass hollow beads preferably have a pressure strength of 100 MPa or more.

  Hereinafter, in Samples 2 to 5, a part of the calcium carbonate of Sample 1 was replaced with glass hollow beads, the volume ratio of calcium carbonate was gradually decreased, and the volume ratio of the glass hollow beads was gradually increased accordingly.

  Specifically, sample 2 has a volume ratio of a matrix resin having a specific gravity of 1.1 to a BMC resin of 41.8 vol%, a glass fiber having a specific gravity of 2.7, a volume ratio of 9.0 vol%, and a carbon dioxide having a specific gravity of 2.7. The volume ratio of the calcium hollow beads having a volume ratio of calcium of 19.7 vol% and a specific gravity of 0.6 was 29.5 vol%. At this time, the specific gravity of the BMC resin was 1.4.

  Incidentally, in this case, the replacement volume ratio a (%) of the glass hollow beads to calcium carbonate is the volume ratio of calcium carbonate in the BMC resin of specific gravity 2.0 not including the glass hollow beads of Sample 1 (vol%), When the volume ratio of calcium carbonate remaining after a part of calcium is replaced with glass hollow beads is c (vol%), the calculation is performed by a = ((bc) / b) × 100. According to this calculation formula, the replacement volume ratio of sample 2 is ((49.1-19.7) /49.1) ≈60%.

  Therefore, in Sample 3, the volume ratio of the matrix resin having a specific gravity of 1.1 to the BMC resin is 41.8 vol%, the volume ratio of the glass fiber having a specific gravity of 2.7 is 9.0 vol%, and the volume of the calcium carbonate having a specific gravity of 2.7. The volume ratio of glass hollow beads having a ratio of 10.6 vol% and a specific gravity of 0.6 was 38.5 vol%. At this time, the specific gravity of the BMC resin was 1.2 and the replacement volume ratio was about 78%.

  In sample 4, the volume ratio of the matrix resin having a specific gravity of 1.1 to the BMC resin is 41.7 vol%, the volume ratio of the glass fiber having a specific gravity of 2.7 is 9.0 vol%, and the volume ratio of the calcium carbonate having a specific gravity of 2.7. The volume ratio of the glass hollow beads having 6.1 vol% and specific gravity of 0.6 was 43.2 vol%. At this time, the specific gravity of the BMC resin was 1.1 and the replacement volume ratio was about 88%.

  In sample 5, the volume ratio of the matrix resin having a specific gravity of 1.1 to the BMC resin is 41.6 vol%, the volume ratio of the glass fiber having a specific gravity of 2.7 is 9.0 vol%, and the volume ratio of the calcium carbonate having a specific gravity of 2.7. The volume ratio of the glass hollow beads having 1.5 vol% and specific gravity of 0.6 was 47.9 vol%. At this time, the specific gravity of the BMC resin was 1.0 and the substitution volume ratio was about 97%.

Therefore, when various characteristics (mechanical strength) are verified for the above-mentioned five types of molded samples, the bending strength of 126 MPa or more, the bending elastic modulus of 10 GPa or more, 50 MPa for the samples 1 to 3 The above tensile strength and Charpy impact strength of 27 kJ / m ² or more were confirmed. These mechanical strengths are sufficiently satisfactory as a base material for a reflector constituting a vehicular lamp.

  However, the prototype product of Sample 1 satisfies the mechanical strength as the base material of the reflector as described above, but is not suitable from the viewpoint of reducing the weight of the vehicular lamp because of its large specific gravity of 2.0. It has become.

  On the other hand, the prototype molded products of Sample 4 and Sample 5 have a specific gravity of 0.6 and small glass hollow beads occupy nearly half the volume of the prototype molded product. It has become. However, on the other hand, since the content of glass hollow beads is large, the mechanical strength is inferior to that of prototype molded products of Samples 1 to 3, and in this respect, it is not suitable for use as a reflector for vehicle lamps. Judged to be appropriate.

  Therefore, from the viewpoint of the mechanical strength required for the reflector constituting the vehicular lamp, it can be seen that the prototype products of Sample 2 and Sample 3 are optimal.

  By the way, glass fiber (fiber reinforcing material) used as a reinforcing material for BMC resin and calcium carbonate (inorganic filler) used as a filler are injection pressure when BMC resin is injected into a cavity from a fan gate at the time of injection molding. May damage or wear the cavity wall.

  Specifically, as shown in FIG. 6 (a partially enlarged view of the mold apparatus and illustrating the flow of the molding resin (BMC resin)), it was injected from the fan gate 21 into the cavity 50 with a predetermined pressure. The BMC resin 60 first hits a portion (first molding resin flow portion) 26 located in front of the fan gate 21 on the inner wall of the cavity 50 of the fixed mold 20 at a predetermined injection speed (flow velocity). The bounced BMC resin 60 again hits a portion (second molding resin flow portion) 31 of the inner wall of the cavity 50 of the movable mold 30 that is opposed.

  In such a flow of the BMC resin 60 in the cavity 50, the sharp protrusions of the glass fiber, particularly the fiber tip and the pulverized amorphous particles of calcium carbonate, damage or wear the inner wall of the cavity 50. In particular, in the first molding resin flow portion 26 of the fixed mold 20 and the second molding resin flow portion 31 of the movable mold 30 where the BMC resin collides at a high speed, it proceeds remarkably. .

  Therefore, as the number of shots of injection molding increases, as shown in FIG. 7 (a partially enlarged view of the mold apparatus and a diagram illustrating the flow of the molding resin (BMC resin)), the first molding resin of the fixed mold 20 When scratches and wear appear in the casting part 26 and the second molding resin casting part 31 of the movable mold 30, and the number of shots further increases, FIG. 8 (molded resin (BMC resin) in a partially enlarged view of the mold apparatus) As shown in FIG. 4, the scratch and wear areas of the first molded resin flow portion 26 of the fixed mold 20 and the second molded resin flow portion 31 of the movable mold 30 are enlarged. At the same time, the degree of scratches and wear becomes severe, and the life of the molding die is shortened.

  At the same time, scratches and wear of the mold are transferred to the molded product, and a rough surface is formed on the surface. When this is used for a reflector, the rough portion adversely affects the optical characteristics.

  Therefore, when injecting the BMC resin into the cavity of the molding die at the time of injection molding, in order to prevent the BMC resin from being scratched or worn on the inner wall of the cavity, the composition ratio of the BMC resin is appropriately set. By setting to, it can be realized without causing a decrease in the mechanical strength of the molded product.

  Specifically, one is to reduce the amount of calcium carbonate added to the BMC resin that damages or wears the inner wall of the cavity 50 of the mold. Moreover, the slipping property at the time of contact is good between spherical glass hollow beads and glass fibers added as inorganic fillers to BMC resin, and between spherical glass hollow beads and calcium carbonate, respectively. Therefore, paying attention to the fact that the contact resistance is low, the BMC resin injected from the fan gate hits the first molding resin flow portion 26 and is bounced back by the first molding resin flow portion 26 to be the second molding resin. When the glass hitting portion 31 hits the glass molding beads 26 that have reached the first molding resin casting portion 26 and the second molding resin casting portion 31 first, the glass fiber and calcium carbonate coming from the rear are the first. The glass resin and the calcium carbonate in contact with the glass hollow beads are prevented from reaching the molding resin flowing part 26 and the second molding resin flowing part 31 of the glass resin, and the flow direction of the glass fiber and calcium carbonate is controlled by good slipperiness. Thereby directed to dynamic direction and is to fluidity of BMC resin is increased.

  Thereby, when the BMC resin is injected into the cavity, the collision probability of the glass fiber and calcium carbonate to the first molding resin flow portion 26 and the first molding resin flow portion 26 is reduced. Generation | occurrence | production of the damage | wound or abrasion with respect to the molded resin flow part 26 and the 1st molded resin flow part 26 is suppressed.

  However, when the amount of glass hollow beads increases (the volume ratio with respect to the BMC resin increases), the mechanical strength of the molded product decreases and the surface smoothness is lost, and a fine uneven surface is formed.

  Therefore, the volume ratio of the glass hollow beads to the BMC resin is set to a range in which the mechanical strength of the molded product does not decrease and the smoothness of the surface is not lost. At that time, the glass hollow beads added to the BMC resin Evaluation of the range of the volume ratio of calcium carbonate to the BMC resin with respect to the prototype sample in the table of FIG. 4 so that the volume ratio of the filler (inorganic filler) consisting of beads and calcium carbonate to the BMC resin maintains a good balance. Based on the results.

  Specifically, as described above, the optimum range of the volume ratio of the glass hollow beads to the BMC resin is 29.5 vol in the sample 2 shown in FIG. 4 from the viewpoint of mechanical strength and surface smoothness of the molded product. % To 38.5 vol% in Sample 3.

  On the other hand, when the volume ratio of the filler consisting of glass hollow beads and calcium carbonate added to the BMC resin is about 49 vol% with a good balance with respect to the BMC resin, the replacement volume ratio a of the glass hollow beads to calcium carbonate is a. The volume ratio of calcium carbonate to BMC resin obtained by changing (%) was in the range of 19.7 vol% to 10.6 vol%.

  In Sample 2 and Sample 3, even when the number of shots of injection molding increases, damage due to scratches or wear on the inner wall of the cavity of the mold due to BMC resin is suppressed, and shortening of the mold life can be prevented.

  As a result, the volume ratio of calcium carbonate of the inorganic filler to the BMC resin is in the range of 19.7 vol% to 10.6 vol%, and the volume ratio of the glass hollow beads of the inorganic filler to the BMC resin is calcium carbonate to the BMC resin. The total volume ratio of the volume ratio of glass and the volume ratio of the glass hollow beads is in a range of about 49 vol%, so that the molded product can be reduced in weight while ensuring good mechanical strength as a reflector for vehicle lamps. It is possible to realize a vehicle lamp reflector made of a molded product using BMC resin as a molding material, which suppresses scratches and wear on the cavity wall surface caused by injection into the cavity of the molding die during injection molding. .

DESCRIPTION OF SYMBOLS 1 ... Vehicle lamp 2 ... Housing 3 ... Front lens 4 ... Seal cover 5 ... Light chamber 6 ... Reflector 7 ... Bulb (light source)
DESCRIPTION OF SYMBOLS 8 ... Composite surface 9 ... Undercoat layer 10 ... Metal reflective film 11 ... Topcoat layer 12 ... Composite reflective surface 12a ... Upper composite reflective surface 12b ... Lower composite reflective surface 13 ... Molding substrate (molded product)
14 ... Light emitting part 20 ... Fixed mold (cavity mold)
DESCRIPTION OF SYMBOLS 21 ... Fan gate 22 ... Runner 23 ... Sprue 24 ... Sprue bush 25 ... Nozzle contact part 26 ... 1st molding resin flow part 30 ... Movable metal mold | die (core metal mold | die)
31 ... 2nd molding resin flow part 40 ... Butting surface (parting surface)
50 ... Cavity 60 ... BMC resin 61 ... Glass hollow bead 62 ... Calcium carbonate

Claims (2)

A vehicle lamp reflector using an injection-molded product made of BMC resin in which at least glass fiber, calcium carbonate and glass hollow beads are added as an inorganic filler to a matrix resin mainly composed of an unsaturated polyester resin,
The calcium carbonate has a volume ratio of 19.7 to 10.6 vol% with respect to the BMC resin, and the glass hollow beads have a total volume of the volume ratio of the calcium carbonate to the BMC resin and the volume ratio of the glass hollow beads. A reflector for a vehicle lamp characterized in that the ratio is in a range of about 49 vol% and a vehicle lamp including the same.   2. The injection molded product according to claim 1, wherein the BMC resin is molded into the cavity through a gate from a direction substantially perpendicular to the surface direction of the cavity of the injection mold. Reflector for vehicle lamp and vehicle lamp provided with the same.

Images