JP2016225314A - Process of manufacture of polycarbonate resin pellet with luminous fluorescent body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lamp cover for protecting a lighting lamp in which it prevents blackish and nonuniform decoloring and extremely improves light transmissivity against emitted light from a light source and even after stopping of the emitting light from the light source, the light emitting by its afterglow can be continued.SOLUTION: A lamp cover 1 is composed of a molded member of polycarbonate resin including at least luminous fluorescent body generating long persistence fluorescent light and light diffusion agent and a reduction rate of illumination intensity when a lamp cover with a thickness of 0.8 mm is used is less than 20% when it is not used. This lamp cover is manufactured by the process of manufacture including the steps for mixing pellet of PC resin containing light diffusion agent and luminous fluorescent body under co-existence of oil, extrusion molding them at a cylinder temperature of 235 to 250°C to get pellet-like PC resin compound, and injection molding the PC resin compound got by the former step at a cylinder temperature of 235 to 260°C or injection molding it at 240 to 280°C.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a lamp cover and a method for manufacturing the same, and particularly has excellent impact resistance. Therefore, in addition to being able to protect the lamp and prevent the broken pieces from being scattered when the lamp is damaged, an earthquake, various accidents, etc. The present invention relates to a lamp cover that can ensure brightness for a certain period of time by the afterglow emitted by the lamp itself even when the lamp is suddenly turned off due to power interruption in the event of a disaster, and a method for manufacturing the same.

  Conventionally, a fluorescent lamp is protected by a material containing a phosphorescent material. For example, a phosphorescent ink containing a phosphorescent material is applied to the surface of a transparent sheet material to form a phosphorescent layer, and the sheet is attached to the fluorescent lamp. Phosphorescent sheet (Patent Document 1) to be used, made of polyvinyl chloride resin containing a long afterglow luminescent material, including a heat-shrinkable tube for coating such as a fluorescent lamp (Patent Document 2), and a phosphorescent material Fluorescent tube cover (Patent Document 3) made of synthetic resin for dimming the irradiation light from the fluorescent tube, a light diffusing polycarbonate resin to which a phosphorescent agent and a light diffusing agent are added, and a silicone compound having a specific structure A light diffusion plate (Patent Document 4) and the like that have been added to impart flame retardancy has been proposed.

  However, the phosphorescent sheet described in Patent Document 1 forms a phosphorescent layer by applying a phosphorescent ink on a transparent resin sheet, and examines the peel strength of the phosphorescent layer as well as the compatibility between the sheet and the ink. However, there are many problems to be solved, and it is still not a sufficient technique to withstand outdoor use. Moreover, the heat-shrinkable tube described in Patent Document 2 is difficult to use for a long time due to deterioration due to heat.

On the other hand, according to the method of molding a synthetic resin containing a phosphorescent material into a desired shape, such as the fluorescent tube cover described in Patent Document 3, mass production is possible, so a reduction in production cost is expected. Is done.
In addition to the mechanical strength and heat resistance, the fluorescent tube cover that covers and protects the tube surface of the fluorescent lamp that is lit has various characteristics such as light transmission as good as possible. Although it is required to be excellent, the polycarbonate resins described in Patent Documents 3 and 4 are recommended as a material for forming a fluorescent tube cover in order to satisfy these various characteristics.

  By the way, Patent Documents 3 and 4 do not describe a specific method for manufacturing a fluorescent tube cover using a polycarbonate resin (hereinafter referred to as PC resin). When, for example, a phosphorescent phosphor or the like is mixed with the resin, and the fluorescent lamp cover is molded with the mixture as it is by an extrusion molding machine, an injection molding machine, or the like, the entire molded body has a blackened or darkened hue. Presenting an adverse effect that the light transmittance is greatly reduced.

  The polyacetal resin (I), the addition polymerization block (a) having the aromatic vinyl compound polymer block (a-1) and the conjugated diene compound polymer block (b-1), and the polycarbonate polymer block A technology for improving impact resistance, flexibility and molding processability by adding a paraffinic oil to a resin composition containing (b) a block copolymer (II) has also been proposed (Patent Document 5). However, there is no description that the phosphorescent agent or the light diffusing agent is added in the document, and therefore there is no suggestion about a method for eliminating the harmful effects as well as the above harmful effects.

JP 2005-213433 A Japanese Patent Laid-Open No. 11-30964 JP 10-199323 A JP 2008-74952 A JP 2006-16419 A

  The present invention has been made in order to eliminate the above-described adverse effects, and is excellent in mechanical strength and heat resistance, has no defects such as blackening or darkening, has very good light transmittance, and is a fluorescent lamp or LED. When used as a tube covering the light source of the lamp or as a cover attached to the outer surface of a general tube covering the light source, the decrease in illuminance is suppressed and the light emission of the lamp is stopped. An object of the present invention is to provide a lamp cover capable of sustaining light emission due to afterglow and to provide a method for manufacturing the lamp cover.

  In order to solve the above-mentioned problems, the present inventors have repeatedly studied a manufacturing process of a lamp cover using a PC resin containing a phosphorescent phosphor as a molding raw material. The PC resin pellets containing a predetermined amount of light diffusing agent are separately prepared, and the pellets and phosphorescent phosphors are not melted and extruded or injection molded in a molding machine. Were mixed in oil, oil was intervened in the grain boundary between the pellet and phosphorescent phosphor particles, and first found that phosphorescent phosphor particles adhered uniformly to the entire pellet surface. If the product is molded into a pellet again, a lamp cover having a milky white body color without blackening or darkening and having a high light transmittance can be obtained by an extrusion molding machine or an injection molding machine. Next And it has led to the proposal of the present invention.

That is, the lamp cover of the present invention is a lamp cover that is attached to the light source of the illumination lamp or the outer surface of the tube, and is made of a polycarbonate resin molded body containing a phosphorescent phosphor and a light diffusing agent. The reduction rate of illuminance when the lamp cover of .8 mm is used is 20% or less when the lamp cover is not used.
At this time, the molded product may further contain an ultraviolet absorber, and the surface and / or the back surface of the molded product may be roughened.
The fluorescent lamp cover of the present invention described above is prepared by kneading a polycarbonate resin pellet containing a light diffusing agent and a phosphorescent phosphor in the presence of oil, and extruding the kneaded material at 235 to 250 ° C. to form a pellet. Including a step (A) of obtaining a polycarbonate resin compound, and a step (B) of extruding the polycarbonate resin compound obtained in the step (A) at 235 to 260 ° C. or injection molding at 240 to 280 ° C. Manufactured by the featured method.
The above-mentioned oil is used in a certain amount (preferably during the kneading step and the extrusion step) during kneading of the light diffusing agent-containing polycarbonate resin pellets and the phosphorescent phosphor or during pelletization by extrusion of the kneaded product. 90% or more) may evaporate.

The lamp cover of the present invention is used as a light source of an illumination lamp, that is, a lamp bulb itself, or attached to the outer surface of the Ryukyu, and is attached to the outer surface of the bulb. Can be detachably mounted.
In addition, since the lamp cover of the present invention is a molded article of PC resin having excellent impact resistance, it is possible to prevent damage caused by an earthquake or an impact when an object hits, as well as an illumination lamp. Even if the constituent material is damaged, scattering of these damaged pieces can be prevented.
Moreover, since the phosphor contains a phosphorescent phosphor, even when the illumination lamp is extinguished due to a sudden shut-off of the power source, the surrounding illumination is secured for a certain time by the afterglow of the phosphorescent phosphor. can do.

  Furthermore, the lamp cover obtained by the production method of the present invention has no lightening or darkening in the molded product, and thus has a high light transmittance. Therefore, a decrease in illuminance when used in an illumination lamp. In addition, since the light diffusing agent is contained in the lamp cover, light emission from the fluorescent lamp and the phosphorescent phosphor becomes uniform due to light scattering inside the lamp cover.

These are drawings which show typically the lamp cover for straight tube | pipe type fluorescent lamps which is an example of the lamp cover of this invention, Comprising: Fig.1 (a) is the perspective view, FIG.1 (b) is FIG. FIG. 1A is a cross-sectional view of a plane perpendicular to the longitudinal direction showing a state in which the lamp cover of the present invention is mounted on a tube of a straight tube fluorescent lamp. . S FIG. 2 is a drawing schematically showing a lamp cover for a round fluorescent lamp, which is another example of the lamp cover according to the present invention, in which FIG. FIG. 2 (c) is a cross-sectional view taken along the line B-B in FIG. 2 (b).

  The lamp cover of the present invention contains a stimulable phosphor that emits long afterglow fluorescence when absorbing ultraviolet light or visible light (that is, a phosphorescent phosphor, hereinafter also referred to as “accumulative phosphor”) and a light diffusing agent. It is made of PC resin, and it is shaped as a bulb of the light source itself of a fluorescent lamp or LED lamp, or a shape that can be detachably attached to the outer surface of the bulb of these illumination lamps to cover the outer surface of the bulb It is formed by processing.

  The lamp cover of the present invention shown in FIG. 1 is used on the outer surface of a tube of a straight tube fluorescent lamp, FIG. 1 (a) is a perspective view, and FIG. 1 (b) is AA in FIG. FIG. The lamp cover 1 shown in FIG. 1 has a hollow, generally cylindrical shape, and has a substantially C-shaped cross-sectional shape in which an opening 2 is formed by cutting parallel to the longitudinal axis at one location on the peripheral surface. In addition, both ends of the cut portion are bent inward from the opening 2 to form the bent portions 3 and 3.

  In order to attach the lamp cover 1 of the present example to the fluorescent lamp 4 installed on the ceiling or the like, the opening 2 is directed from the lower side of the straight tube type fluorescent lamp 4 to the direction facing the fluorescent lamp 4, and the opening 2 is formed. The lamp cover 1 is fixed to the fluorescent lamp 4 by being pushed into the fluorescent lamp 4 in a state of being lightly spread in a direction perpendicular to the longitudinal direction and fitting the inner peripheral surface of the lamp cover 1 to the outer peripheral surface of the fluorescent lamp 4. . At this time, the degree of adhesion between the fluorescent lamp 4 and the lamp cover 1 may be adjusted by selecting the inner diameter r of the lamp cover 1 to be used and the outer diameter of the tube of the fluorescent lamp 4.

  FIG. 1C is a cross-sectional view for explaining a state in which the lamp cover 1 shown in FIG. 1A is attached to a straight tube fluorescent lamp, and the tube of the fluorescent lamp 4 attached to the lamp fixture 6 Is covered with the lamp cover 1 except for the opening 2 of the lamp cover 1 (the upper part of the tube of the fluorescent lamp 4), and the bent part 3 and the opening 2 of the lamp cover 1 are spread outward. The lamp cover 1 is fitted and held on the fluorescent lamp 4 by the restoring force.

  FIG. 2 shows another embodiment of the lamp cover according to the present invention, schematically showing a lamp cover for a round fluorescent lamp. FIG. 2 (a) is a perspective view of the lamp cover 11, and FIG. FIG. 2B is a plan view of the round fluorescent lamp 14 equipped with the lamp cover 11 as viewed from below, and FIG. 2C is a cross-sectional view taken along line BB in FIG.

  As in the lamp cover 1 shown in FIG. 1, the lamp cover 11 of this example has a substantially annular hollow cylindrical shape in which a hollow cylinder having a C-shaped cross section is bent into an annular shape in accordance with the round shape of the round fluorescent lamp. As shown in FIG. 2 (a), the circular hollow cylinder 14 is attached to and detached from the round fluorescent lamp 14 at one location on the peripheral surface of the annular hollow cylinder. We are trying to improve workability at the time.

In order to attach the lamp cover 11 to the fluorescent lamp 14 attached to the lamp fixture 16, the fluorescent lamp 14 is pushed into the fluorescent lamp 14 from the opening 12 with the opening 12 of the lamp cover 11 being expanded from directly below the fluorescent lamp 14. Thus, the lamp cover 11 is held by the fluorescent lamp 14 by the bending portion 13 and the restoring force when the opening 12 is widened.
In the lamp cover 11 of this example, as shown in FIG. 2B, a connector portion 15, which is a non-light emitting portion of the fluorescent lamp 14, is a portion cut at one place on the peripheral surface of the substantially annular hollow cylinder. Install so that it matches the position of.

  The PC resin that is the raw material of the lamp cover of the present invention can be any of aromatic polycarbonate, aliphatic polycarbonate, and aromatic-aliphatic polycarbonate. Among them, the aromatic dihydroxy compound is phosgene in terms of excellent light diffusibility. Alternatively, aromatic polycarbonates are recommended, including thermoplastic aromatic polycarbonates obtained by reaction with carbonic diesters.

The stimulable phosphor contained in the PC resin is, for example, an alkaline earth metal aluminate-based phosphor activated with rare earth elements such as SrAl ₂ O ₄ : Eu, Dy, (Sr, Mg) Si ₂ O ₇ : Conventionally known, including alkaline earth metal silicate phosphors activated with rare earth elements such as Eu and Dy, and copper activated alkaline earth metal sulfide phosphors such as ZnS: Cu. There are phosphorescent phosphors that exhibit long afterglow emission when absorbing ultraviolet rays and short-wavelength visible light, and organic phosphors that emit phosphorescence when absorbing ultraviolet rays and visible rays.

The light diffusing agent contained in the PC resin together with the above phosphorescent phosphor further improves the diffusibility of the light from the light source and the light emission from the phosphorescent phosphor coexisting in the lamp cover, and passes through the lamp cover. In order to make uniform the emitted light emitted.
Examples of the light diffusing agent added to the lamp cover include low refractive index inorganic fine particles such as calcium carbonate, barium sulfate, silica, and glass fine particles known as PC resin light diffusing agents, polystyrene resins, silicone resins, and silicon. Cross-linked particles, polystyrene resin, organic fine particles such as acrylic-styrene copolymer fine particles, and composites thereof are used.

  In the lamp cover of the present invention, as other additives, an ultraviolet absorber for suppressing yellowing and deterioration due to ultraviolet rays, a fluorescent whitening agent for changing the color tone of the molded body to white or bluish white, or difficult. You may mix | blend a flame retardant etc. suitably.

If the content of the stimulable phosphor in the lamp cover of the present invention is too small, the afterglow intensity of the lamp cover cannot be sufficiently obtained, and conversely if too large, the moldability and the mechanical strength of the molded body are reduced. Although the afterglow intensity of the stimulable phosphor increases, the transmittance of the emitted light from the light source is further reduced.
Therefore, the amount of the stimulable phosphor added to the lamp cover of the present invention is preferably 1 to 50% by weight and more preferably 3 to 30% by weight with respect to the amount of the PC resin.

In addition, if the content of the light diffusing agent in the lamp cover of the present invention is too small, the light diffusing effect cannot be obtained. In addition, the mechanical strength of the molded body is reduced, and the transmittance of emitted light from the light source is further reduced.
Therefore, the amount of the light diffusing agent is preferably 0.05 to 15% by weight, and more preferably 0.1 to 10% by weight with respect to the amount of the PC resin.
In addition, the content when the ultraviolet absorber is contained in the lamp cover of the present invention is preferably 0.01 to 5% by weight with respect to the amount of the PC resin.

  The lamp cover of the present invention is made of a PC resin with good light transmission, and since it does not cause blackening or darkening that tends to occur during the manufacture of PC resin pellets or molding of the lamp cover, it was used as a light source bulb. In addition, when used on the outer surface of a normal tube, the decrease in the amount of light from the light source is small and the decrease in illuminance is suppressed, and the storage phosphor is excited by the light from the light source. Some light emission is also added.

In the lamp cover of the present invention, the lamp cover is used by adjusting the contents of the phosphorescent phosphor, the light diffusing agent, and other additives contained in the PC resin within the above-described ranges. The degree of illuminance reduction of the illumination lamp and the afterglow intensity of the cover when the lamp is extinguished are appropriately adjusted.
Comparing the illuminance on the same plane at a certain distance from the lit illumination lamp for each of the case where the lamp cover of the present invention is used and the case where it is not used, for example, a book having a wall thickness of 0.8 mm The illuminance of the lamp cover of the invention is 80% or more of the illuminance when the lamp cover is not used, and the illuminance reduction rate due to the use of the lamp cover of the invention is 20% or less.

As the thickness of the lamp cover decreases, the amount of light transmitted from the light source increases, and the ratio between the illuminance (I) when covered by the lamp cover and the illuminance (I ₀ ) when not covered by the cover ( I / I ₀ ) naturally increases as the cover thickness decreases, and the degree of decrease in the amount of light transmitted from the light source due to covering with the lamp cover decreases, but the mechanical strength of the lamp cover decreases, so the light source On the contrary, as the thickness of the lamp cover increases, the ratio (I / I ₀ ) decreases and the amount of light transmitted from the light source decreases.
Therefore, although not particularly limited, the thickness of the lamp cover is set to about 0.5 to 3 mm from a practical viewpoint according to the use environment.

  In addition, the lamp cover of the present invention depends on the type of the stimulable phosphor contained, but by selecting the stimulable phosphor, for example, after being mounted on the fluorescent lamp and turned on, the lamp cover is turned on for a predetermined time and then turned off. After several tens of minutes or hours, a relatively high emission luminance (afterglow luminance) can be maintained.

In order to manufacture the lamp cover of the present invention, first, a PC resin powder and a light diffusing agent are blended, and then melt kneaded using a known method, for example, an extruder or the like, extruded, and light diffusing agent. Prepare containing PC resin pellets.
In addition, when it contains other various additives, such as a ultraviolet absorber, a flame retardant, and a fluorescent whitening agent, what is necessary is just to mix these additives with a light-diffusion agent at the time of the said pellet preparation.

Next, the light diffusing agent-containing PC resin pellets thus obtained together with a predetermined amount of phosphorescent phosphors, for example, saturated hydrocarbon oils, unsaturated hydrocarbon oils, vegetable oils such as intermediate to higher fatty acids, animal oils, minerals, etc. After adding the oil which consists of 1 type or multiple types of oil, these are mixed, it is melt-kneaded with an extruder etc. at cylinder temperature 235-250 degreeC, and it extrusion-molds, and manufactures a pellet-form PC resin compound. At this time, the screw rotation speed of the extruder is preferably set to be higher than that in general extrusion molding.
The rotational speed at this time improves the kneading of the PC resin pellet containing the light diffusing agent and other additives (hereinafter, the PC resin pellet containing the light diffusing agent) and the phosphorescent phosphor and the remelted state of the pellet. Therefore, in order to evaporate most of the coexisting oil during this kneading and remelting (hereinafter sometimes simply referred to as “kneading”), it is preferably about 15 to 35 rpm. If it is faster than this, not only kneading of the PC pellet and phosphorescent phosphor, but also the transpiration of the oil does not proceed to the desired level, and even if it is slower than this, not only these actions are saturated, but also the time for the re-pelletizing process. This increases the manufacturing cost.

  The amount of the oil used in the present invention is desirably such that it covers the entire surface of each PC resin pellet containing a light diffusing agent, and generally 0.1 to 0.1% of the amount (weight) of the pellet. 5% by weight is suitable. If it is less than this, the phosphorescent phosphor particles are difficult to uniformly adhere to the entire surface of the pellet, and if it is more than this, the pellet will idle in the cylinder and the resin cannot be fed. In the course of kneading the phosphorescent phosphor and in the course of pelletization by extruding the kneaded product, the oil may not sufficiently evaporate, and a sticky feeling may remain in the molded body made of the pellet as well as the pellet. .

  The light diffusing agent obtained as described above and a pellet-like PC compound containing a stimulable phosphor as essential components are used as raw materials for molding, and extrusion molding is performed at 235 to 260 ° C or injection molding is performed at 240 to 280 ° C. The lamp cover of the present invention is obtained.

  In the present invention, the phosphorescent phosphor particles are evenly attached to each of the PC resin pellet lumps by interposing oil at the grain interface between the PC resin pellets containing the light diffusing agent and the phosphorescent phosphor. In addition, since the lubricity is improved by the coexisting oil, it is hardly affected by friction and heat deterioration in the molding machine when re-pelletized after kneading, and the light diffusing agent is contained in the PC resin pellet before re-pelletizing Is contained in advance, the pellet-shaped phosphorescent phosphor-containing PC resin compound obtained by re-pelletizing, and the lamp cover of the present invention which is a molded product of this PC resin compound are blackened and darkened, Or coloring, such as a fading, is not recognized and the fall of light transmittance is suppressed.

The raw materials used in the following examples and comparative examples are as follows.
(A) Polycarbonate resin: Aromatic polycarbonate resin synthesized from bisphenol A and phosgene (molecular weight 27000-28000, melting point 240 ° C., MVR 7 cm ³ / min.) 100 parts by weight (b) Storage phosphor: Sr ₄ Al ₁₄ O 25: Eu , Dy 7.5 parts by weight (c) Light diffusing agent: calcium carbonate 1.5 parts by weight (d) UV absorber: benzophenone 1 part by weight (e) Flame retardant: phosphorus flame retardant 3.5 parts by weight (f ) Oil: Saturated hydrocarbon oil / vegetable oil / higher fatty acid compounded oil (“SANYO SPREDER N-22” manufactured by Sanyo Chemical Industries)
0.5 parts by weight with respect to the amount of the light diffusing agent-containing PC resin pellet

[Example 1]
After mixing the raw materials of the above (a), (c), (d), and (e), the mixture is kneaded using an extrusion molding machine, extruded, and contains the light diffusing agent. Resin pellets were produced.
Next, after the PC resin pellets of Example 1 and the raw materials (b) and (f) were put into a tumbler and mixed, they were kneaded by an extruder at 250 ° C. and a screw rotation speed (25 rpm). The pellet-shaped PC resin compound containing the stimulable phosphor of Example 1 was produced by extrusion molding.
The resulting PC-compound containing stimulable phosphors has a milky white color, and has a smooth surface with no stickiness. Therefore, most of the oil is evaporated during kneading and re-pelletizing. I understand.
This pellet-shaped resin compound was kneaded at 260 ° C. with a screw rotation speed (12 rpm) by an extrusion molding machine and extruded to produce the lamp cover of Example 1 having a thickness of 0.8 mm and the shape shown in FIG. .

[Example 2]
Using the stimulable phosphor-containing pellet-like PC resin compound obtained in Example 1 above, a lamp cover of Example 2 having a thickness of 0.8 mm and having the shape shown in FIG. 2 was produced by an injection molding machine.

[Comparative Example 1]
After mixing the raw materials (a), (b), (c), (d), and (e) with a blender, they are kneaded with an extruder at 250 ° C. and a screw rotation speed (25 rpm), and extruded. Molded to produce a stimulable phosphor-containing pellet PC resin compound.
The resulting stimulable phosphor-containing pellet-like PC resin compound had a smooth surface and no sticky feeling, but blackening was observed throughout the pellet as described below.
This stimulable phosphor-containing pellet-shaped PC resin compound was extruded under the same conditions as in Example 1 using an extruder, and the lamp of Comparative Example 1 having a thickness of 0.8 mm and having the shape shown in FIG. A cover was manufactured.

[Comparative Example 2]
The same as Comparative Example 1 except that the raw materials (a), (b), (d), (e), and (f) are used (however, the amount of (f) is (a), (b) , (D), (e) 0.5 wt% with respect to the total amount), the stimulable phosphor-containing pellet-shaped PC resin compound of Comparative Example 2 was produced.
In the obtained stimulable phosphor-containing pellet-like PC resin compound, in addition to the fact that the entire pellet had a solid surface feeling, blackening was observed over the entire pellet as in Comparative Example 1.
Using this pellet-shaped PC resin compound, extrusion molding was performed under the same conditions as in the example to produce a lamp cover of Comparative Example 2 having a thickness of 0.8 mm and having the shape shown in FIG.

[Comparative Example 3]
A stimulable phosphor-containing pellet-shaped PC resin compound was produced in the same manner as in Example 1 except that the raw material (f) was not used.
As in the case of Comparative Example 1, the obtained stimulable phosphor-containing pellet-like PC resin compound did not have a sticky feeling, but darkening and uneven color were observed throughout the pellet as described below.
Using this pellet-shaped PC resin compound, a lamp cover of Comparative Example 3 having a thickness of 0.8 mm and having the shape shown in FIG. 1 was manufactured under the same conditions as in Example 1.

[Comparative Example 4]
The raw materials (a) to (f) are the same as in Example 1 except that the raw materials are kneaded by the extrusion molding machine used in the cover molding machine of Example 1 and extruded (however, the amount of (f) is As in Comparative Example 2, a lamp cover of Comparative Example 4 having a thickness of 0.8 mm and having the shape shown in FIG. 1 was produced.

[Evaluation of lamp cover]
Regarding Examples 1 and 2 and Comparative Examples 1 to 4 produced as described above, (1) Presence / absence (degree) of blackening of stimulable phosphor-containing pellet-like PC resin compound (in Table 1, material) , (2) Whether the molded lamp cover is blackened (degree), (3) Illuminance reduction rate when the lamp cover is mounted on the outer surface of a fluorescent lamp tube, and (4) Evaluation of afterglow brightness did. The evaluation method for each evaluation item is as follows.

(1) Presence / absence (degree) of blackening of the material: x when the blackened portion and the overall darkening are clearly recognized, x when the blackening and the color unevenness are slightly recognized as a whole, Δ A clean milky white product was marked with ◯.
(2) Presence / absence (degree) of blackening of fluorescent lamp cover (molded product): Visual observation was performed and evaluation was performed in the same manner as in (1) above.
(3) Illuminance reduction rate by the fluorescent lamp cover: Using a luminometer (FUGI I, DEGIAL LUX METER LX-1010B) on a plane 3 m away from the lit fluorescent lamp (40 W, straight tube type D65) The illuminance [I ₀ ] and the illuminance [I] on the plane when each lamp cover is mounted on the lamp are respectively measured, and the measured value is expressed by the equation {1-([I] / [I ₀ ])} X100 (%) was applied, and the obtained value was defined as the illuminance reduction rate of the fluorescent lamp cover.
(4) Afterglow intensity of the fluorescent lamp cover (afterglow brightness): The fluorescent lamp (40 W, straight tube type D65) equipped with the lamp cover is continuously turned on for 60 minutes, then turned off, and immediately after the lamp is turned off, 3 m away from the lamp cover. The luminance on the plane [I _P30 ] was measured with a luminance meter (KONIKA MINOLTA, LS-100).
The evaluation results of the above (1) to (5) are shown in Table 1.

  As can be seen from the results shown in Table 1, in Examples 1 and 2 according to the present invention, it is possible to provide a lamp cover that does not have blackening or darkening, has a uniform gray white color, and has a low light transmittance.

  In contrast, Comparative Examples 1 and 3 in which no oil coexists when mixing the PC resin pellets and the phosphorescent phosphor, Comparative Example 2 in which the oil coexists but does not contain a light diffusing agent, or all the raw materials at once. In Comparative Example 4 in which kneading and extrusion molding are performed, blackening or grayish black is observed as a whole, and the lamp cover has a large decrease in light transmittance.

Example 3
The composition of the raw materials used in the above Examples and Comparative Examples was as follows, and Example 1 except that the screw rotation speed during kneading of the light diffusing agent-containing PC resin pellet and the stimulable phosphor was 35 rpm. , 2 to produce the lamp cover of the present invention.
As a result of evaluating the obtained lamp cover in the same manner as that obtained in Examples 1 and 2, it was confirmed that the same performance as that obtained in Examples 1 and 2 was exhibited.
(A) Polycarbonate resin: 100 parts by weight (b) Storage phosphor: 3 parts by weight (c) Light diffusing agent: 0.1 part by weight (d) Ultraviolet absorber: 1 part by weight (e) Flame retardant: 5 parts by weight (f) oil: 0.1 parts by weight with respect to the amount of light diffusing agent-containing pellets

Example 4
A lamp cover of the present invention was produced in the same manner as in Example 3 except that the raw materials used in the above Examples and Comparative Examples were mixed as follows.
The lamp cover obtained was evaluated in the same manner as that obtained in Examples 1, 2, and 3. As a result, it was confirmed that the same performance as that obtained in Examples 1, 2, and 3 was exhibited. did. However, although the afterglow luminance maintained a high value for a long time (about 10 hours), the illuminance reduction rate when the lamp was lit showed a value slightly exceeding 20%.
(A) Polycarbonate resin: 100 parts by weight (b) Storage phosphor: 30 parts by weight (c) Light diffusing agent: 10 parts by weight (d) Ultraviolet absorber: 1 part by weight (e) Flame retardant: 3.5 parts by weight Part (f) oil: 5 parts by weight based on the amount of the light diffusing agent-containing pellet

  Since the lamp cover of the present invention is a molded body made of PC resin, it is excellent in mechanical strength and transparency, and is used by mounting it on the light source itself or the tube spherical surface of the illumination lamp, so that the lamp cover due to impact from the outside can be used. Even if it breaks or breaks, the broken pieces are prevented from scattering, and the cover contains a phosphorescent phosphor. The lamp cover continues to emit light even when the lighting lamp is turned off due to a sudden power failure. Therefore, it can be used for crime prevention lights and evacuation guide lights in addition to general indoor illumination lights.

1, 11 ...... Lamp cover 2, 12 ...... Opening part 3, 13 ...... Bending part 4, 14 ...... Lighting lamp 15 ............ Connector part 6, 16 ...... Lamp mounting fixture

The present invention relates to a method for producing a phosphorescent phosphor-containing polycarbonate resin pellet, and more particularly, to a method for producing the pellet having a surface free from darkening due to the phosphorescent phosphor and other additives .

Conventionally, for example, to protect a fluorescent lamp with a material containing a phosphorescent material, a phosphorescent ink containing a phosphorescent material is applied to the surface of a transparent sheet material to form a phosphorescent layer, and the sheet is attached to the fluorescent lamp Phosphorescent sheet (Patent Document 1) to be used, made of polyvinyl chloride resin containing a long afterglow luminescent material, including a heat-shrinkable tube for coating such as a fluorescent lamp (Patent Document 2), and a phosphorescent material Fluorescent tube cover (Patent Document 3) made of synthetic resin for dimming the irradiation light from the fluorescent tube, a light diffusing polycarbonate resin to which a phosphorescent agent and a light diffusing agent are added, and a silicone compound having a specific structure A light diffusion plate (Patent Document 4) and the like that have been added to impart flame retardancy has been proposed.

  However, the phosphorescent sheet described in Patent Document 1 forms a phosphorescent layer by applying a phosphorescent ink on a transparent resin sheet, and examines the peel strength of the phosphorescent layer as well as the compatibility between the sheet and the ink. However, there are many problems to be solved, and it is still not a sufficient technique to withstand outdoor use. Moreover, the heat-shrinkable tube described in Patent Document 2 is difficult to use for a long time due to deterioration due to heat.

On the other hand, according to the method of molding a synthetic resin containing a phosphorescent material into a desired shape, such as the fluorescent tube cover described in Patent Document 3, mass production is possible, so a reduction in production cost is expected. Is done.
In addition to the mechanical strength and heat resistance, the fluorescent tube cover that covers and protects the tube surface of the fluorescent lamp that is lit has various characteristics such as light transmission as good as possible. Although it is required to be excellent, the polycarbonate resins described in Patent Documents 3 and 4 are recommended as a material for forming a fluorescent tube cover in order to satisfy these various characteristics.

  By the way, Patent Documents 3 and 4 do not describe a specific method for manufacturing a fluorescent tube cover using a polycarbonate resin (hereinafter referred to as PC resin). When, for example, a phosphorescent phosphor or the like is mixed with the resin, and the fluorescent lamp cover is molded with the mixture as it is by an extrusion molding machine, an injection molding machine, or the like, the entire molded body has a blackened or darkened hue. Presenting an adverse effect that the light transmittance is greatly reduced.

  The polyacetal resin (I), the addition polymerization block (a) having the aromatic vinyl compound polymer block (a-1) and the conjugated diene compound polymer block (b-1), and the polycarbonate polymer block A technology for improving impact resistance, flexibility and molding processability by adding a paraffinic oil to a resin composition containing (b) a block copolymer (II) has also been proposed (Patent Document 5). However, there is no description that the phosphorescent agent or the light diffusing agent is added in the document, and therefore there is no suggestion about a method for eliminating the harmful effects as well as the above harmful effects.

JP 2005-213433 A Japanese Patent Laid-Open No. 11-30964 JP 10-199323 A JP 2008-74952 A JP 2006-16419 A

The present invention has been made in order to eliminate the above-described adverse effects, and is excellent in mechanical strength and heat resistance, has no defects such as blackening or darkening, has very good light transmittance, and is a fluorescent lamp or LED. When used as a tube covering the light source of the lamp or as a cover attached to the outer surface of a general tube covering the light source, the decrease in illuminance is suppressed and the light emission of the lamp is stopped. An object of the present invention is to provide a method for producing phosphorescent phosphor-containing polycarbonate resin pellets suitable for use when producing a lamp cover capable of sustaining light emission due to afterglow , or when producing various other molded products. .

  In order to solve the above-mentioned problems, the present inventors have repeatedly studied a manufacturing process of a lamp cover using a PC resin containing a phosphorescent phosphor as a molding raw material. The PC resin pellets containing a predetermined amount of light diffusing agent are separately prepared, and the pellets and phosphorescent phosphors are not melted and extruded or injection molded in a molding machine. Were mixed in oil, oil was intervened in the grain boundary between the pellet and phosphorescent phosphor particles, and first found that phosphorescent phosphor particles adhered uniformly to the entire pellet surface. If the product is molded into a pellet again, a lamp cover having a milky white body color without blackening or darkening and having a high light transmittance can be obtained by an extrusion molding machine or an injection molding machine. Next And it has led to the proposal of the present invention.

That is, the phosphorescent phosphor-containing polycarbonate resin pellet of the present invention is prepared by kneading a polycarbonate resin pellet containing a light diffusing agent and a phosphorescent phosphor in the presence of oil, and extruding the kneaded product at 235 to 250 ° C. It is produced by a method characterized by a pellet shape by.
The above-mentioned oil is used in a certain amount (preferably during the kneading step and the extrusion step) during kneading of the light diffusing agent-containing polycarbonate resin pellets and the phosphorescent phosphor or during pelletization by extrusion of the kneaded product. 90% or more) may evaporate.
In addition, but it may also contain a further UV absorber in the pellet of the above Symbol.

Polycarbonate resin pellets obtained by the process of the present invention (hereinafter sometimes referred to as "pellets of the present invention") includes a light diffusing agent and phosphorescent phosphor, is had in it the lamp cover, the illumination lamp The light source itself, that is, the molded lamp used as the bulb itself of the illumination lamp, or mounted on the outer surface of the Ryukyu , and other various molded materials .
In addition, since the molded product obtained using the pellets of the present invention is a molded product of PC resin having excellent impact resistance, it is prevented from being damaged due to an impact during an earthquake or an impact when hit by an object. Of course, even if the molded body is damaged, it is possible to prevent scattering of these broken pieces.
In addition, since the molded body contains a phosphorescent phosphor, when the molded body is used as a lamp cover or as a light source for a proof lamp itself , the illumination lamp is turned off due to a sudden power interruption. In this case, the surrounding illumination can be secured for a certain period of time by the afterglow of the phosphorescent phosphor.

Furthermore, the molded product obtained using the pellets of the present invention has no lightening or darkening, and thus has a high light transmittance. Therefore, for example , it was used as a cover for an illumination lamp or a tube for an illumination lamp. reduction of the illuminance of the time is not small. Moreover, since this is the molded body contains the light diffusing agent, the scattering of light within the green body, for example, as well from the lamp when used as the lamp cover, etc., phosphorescent included in the cover itself Light from the fluorescent phosphor becomes uniform.

These are drawings which show typically the lamp cover for straight tube | pipe type fluorescent lamps which is an example of the lamp cover shape | molded from the pellet of this invention, Comprising : Fig.1 (a) is the perspective view, FIG. (B) is a cross-sectional view taken along line AA in FIG. 1 (a), and FIG. 1 (c) is a longitudinal view showing a state in which the lamp cover of FIG. 1 (a) is mounted on a tube of a straight tube fluorescent lamp. It is sectional drawing of a surface perpendicular | vertical to a direction. These are drawings which show typically the lamp cover for round fluorescent lamps which is another example of the lamp cover shape | molded from the pellet of this invention, Comprising : Fig.2 (a) is the perspective view, FIG. 2 (b) is a plan view of the state in which the lamp cover of FIG. 2 (a) is mounted on the bulb of the round fluorescent lamp, as viewed from the lower side of the bulb, and FIG. 2 (c) is a B- in FIG. 2 (b). FIG.

The lamp cover formed using the pellets of the present invention as a material is a stimulable phosphor that emits long persistence fluorescence when absorbing ultraviolet rays or visible light (that is, phosphorescent phosphor, hereinafter also referred to as “accumulative phosphor”). And a PC resin containing a light diffusing agent, which is detachably mounted on the outer surface of the tube of the fluorescent lamp or LED lamp, or on the outer surface of the tube of the illumination lamp. It is molded into a shape that can cover the surface.

Shown to La Npukaba in FIG. 1, which is used in tube outer surface of the straight tube type fluorescent lamp, FIG. 1 (a) is a perspective view, FIG. 1 (b) A-A line cross section of FIG. It is an arrow view. The lamp cover 1 shown in FIG. 1 has a hollow, generally cylindrical shape, and has a substantially C-shaped cross-sectional shape in which an opening 2 is formed by cutting parallel to the longitudinal axis at one location on the peripheral surface. In addition, both ends of the cut portion are bent inward from the opening 2 to form the bent portions 3 and 3.

  In order to attach the lamp cover 1 of the present example to the fluorescent lamp 4 installed on the ceiling or the like, the opening 2 is directed from the lower side of the straight tube type fluorescent lamp 4 to the direction facing the fluorescent lamp 4, and the opening 2 is formed. The lamp cover 1 is fixed to the fluorescent lamp 4 by being pushed into the fluorescent lamp 4 in a state of being lightly spread in a direction perpendicular to the longitudinal direction and fitting the inner peripheral surface of the lamp cover 1 to the outer peripheral surface of the fluorescent lamp 4. . At this time, the degree of adhesion between the fluorescent lamp 4 and the lamp cover 1 may be adjusted by selecting the inner diameter r of the lamp cover 1 to be used and the outer diameter of the tube of the fluorescent lamp 4.

  FIG. 1C is a cross-sectional view for explaining a state in which the lamp cover 1 shown in FIG. 1A is attached to a straight tube fluorescent lamp, and the tube of the fluorescent lamp 4 attached to the lamp fixture 6 Is covered with the lamp cover 1 except for the opening 2 of the lamp cover 1 (the upper part of the tube of the fluorescent lamp 4), and the bent part 3 and the opening 2 of the lamp cover 1 are spread outward. The lamp cover 1 is fitted and held on the fluorescent lamp 4 by the restoring force.

Lamp cover shown in FIG. 2 is a lamp cover for round fluorescent lamp, FIG. 2 (a) is a perspective view of the lamp cover 11, FIG. 2 (b) round fluorescent fitted with the lamp cover 11 It is the top view which looked at the lamp | ramp 14 from the lower side, FIG.2 (c) is a BB sectional view taken on the line of the same figure.

  As in the lamp cover 1 shown in FIG. 1, the lamp cover 11 of this example has a substantially annular hollow cylindrical shape in which a hollow cylinder having a C-shaped cross section is bent into an annular shape in accordance with the round shape of the round fluorescent lamp. As shown in FIG. 2 (a), the circular hollow cylinder 14 is attached to and detached from the round fluorescent lamp 14 at one location on the peripheral surface of the annular hollow cylinder. We are trying to improve workability at the time.

In order to attach the lamp cover 11 to the fluorescent lamp 14 attached to the lamp fixture 16, the fluorescent lamp 14 is pushed into the fluorescent lamp 14 from the opening 12 with the opening 12 of the lamp cover 11 being expanded from directly below the fluorescent lamp 14. Thus, the lamp cover 11 is held by the fluorescent lamp 14 by the bending portion 13 and the restoring force when the opening 12 is widened.
In the lamp cover 11 of this example, as shown in FIG. 2B, a connector portion 15, which is a non-light emitting portion of the fluorescent lamp 14, is a portion cut at one place on the peripheral surface of the substantially annular hollow cylinder. Install so that it matches the position of.

As the PC resin in the pellet of the present invention which is the raw material of the lamp cover shown in FIGS. 1 and 2 , any of aromatic polycarbonate, aliphatic polycarbonate, and aromatic-aliphatic polycarbonate can be used, and in particular, it has excellent light diffusibility. In this respect, aromatic polycarbonates are recommended, including thermoplastic aromatic polycarbonates obtained by reacting aromatic dihydroxy compounds with phosgene or diesters of carbonic acid.

The stimulable phosphor contained in the PC resin is, for example, an alkaline earth metal aluminate-based phosphor activated with rare earth elements such as SrAl ₂ O ₄ : Eu, Dy, (Sr, Mg) Si ₂ O ₇ : Conventionally known, including alkaline earth metal silicate phosphors activated by rare earth elements such as Eu and Dy, and copper activated alkaline earth metal sulfide phosphors such as ZnS: Cu. There are phosphorescent phosphors that exhibit long afterglow emission when absorbing ultraviolet rays and short-wavelength visible light, and organic phosphors that emit phosphorescence when absorbing ultraviolet rays and visible rays.

Further, the light diffusing agent to be contained in the PC resin together with the above phosphorescent phosphor further improves the diffusibility of light from the light source and light emission from the phosphorescent phosphor coexisting in a molded body such as a lamp cover, In order to make uniform the emitted light radiated | emitted via molded objects, such as a lamp cover, it is contained.
Examples of the light diffusing agent in the present invention include low-refractive-index inorganic fine particles such as calcium carbonate, barium sulfate, silica, and glass fine particles known as PC resin light diffusing agents, polystyrene resins, silicone resins, silicon crosslinked particles, and polystyrene. Resin, organic fine particles such as acrylic-styrene copolymer fine particles, and composites thereof are used.

In addition, in the pellets of the present invention, as other additives, an ultraviolet absorber for suppressing yellowing and deterioration due to ultraviolet rays, a fluorescent whitening agent for changing the color tone of the molded body to white or bluish white, or a flame retardant Etc. may be appropriately blended.

Afterglow intensity of pellets in the stimulable phosphor content is too small and the lamp cover, etc. molded product obtained from the pellets of the present invention of the present invention is not sufficiently obtained, and moldability and molded body too large conversely In addition to the decrease in the mechanical strength, the persistence intensity of the stimulable phosphor is increased, but the transmittance of the emitted light from the light source is further decreased.
Therefore, the amount of the stimulable phosphor added to the pellets as the material of the molded body such as the lamp cover of the present invention is preferably 1 to 50% by weight with respect to the amount of the PC resin, and 3 to 30 It is more preferable to set the weight%.

In addition, if the content of the light diffusing agent in the pellet of the present invention is too small, the light diffusing effect cannot be obtained, and conversely if too large, the content of the stimulable phosphor is increased as in the case of the present invention. The moldability obtained by using pellets and the mechanical strength of the molded body are lowered, and the transmittance of emitted light from the light source is further reduced.
Therefore, the amount of the light diffusing agent is preferably 0.05 to 15% by weight, and more preferably 0.1 to 10% by weight with respect to the amount of the PC resin.
Moreover, it is preferable that content in the case of making an ultraviolet absorber contain in the pellet of this invention shall be 0.01-5 weight% with respect to the quantity of PC resin.

Pellets of the present invention comprises a light transmissive good PC resin, moreover and during the production of pellets, for prone blackening or darkening the like at the time of molding of the molded body of the pellet and the material does not occur, the molded body For example, when used as a tube of a light source, or when used as a lamp cover on the outer surface of a normal tube, the decrease in the amount of light from the light source is small and the decrease in illuminance is suppressed. Some light emitted by the stimulable phosphor being excited by this light is also added.

In the pellet of the present invention, for example, a lamp cover obtained from this pellet by adjusting the contents of the phosphorescent phosphor, the light diffusing agent, and other additive substances contained in the PC resin within the above-described range. The degree of decrease in illuminance of the illumination lamp due to the use of and the afterglow intensity of the cover when the lamp is extinguished are appropriately adjusted.
For each case where lamp cover this is not used and if used, when comparing the illuminance on the lit coplanar spaced a predetermined distance from the illumination lamp is, for example, wall thickness 0.8mm of the present invention the illuminance of the lamp cover obtained by the pellets as a material, the lamp cover is not more than 80% of the illuminance when not in use, reduction rate of the illuminance due to the use of this lamp cover 20% or less is there.

Lamp cover the pellets of the present invention as a material, the amount of transmitted light from a light source with a thickness decreases and increases, the illuminance (I ₀₎ when not a covered We illuminance (I) when covered by a lamp cover Ratio (I / I ₀ ) naturally increases as the thickness of the cover decreases, and the degree of decrease in the amount of light transmitted from the light source by covering with the lamp cover decreases, but the mechanical strength of the lamp cover decreases. However, as the thickness of the lamp cover increases, the ratio (I / I ₀ ) becomes smaller and the amount of light transmitted from the light source decreases.
Therefore, although not particularly limited, the thickness of the lamp cover is set to about 0.5 to 3 mm from a practical viewpoint according to the use environment.

In addition , the lamp cover made of the pellets of the present invention, depending on the type of the stimulable phosphor contained, can be turned on for a predetermined time after being mounted on the fluorescent lamp and turned on, for example, by selecting the stimulable phosphor. After that, after a few tens of minutes after turning off, or a few hours later, it is possible to maintain a relatively high emission luminance (afterglow luminance).

In order to produce the pellets of the present invention, first, after blending the PC resin powder and the light diffusing agent, melt-kneading using a known method, for example, an extruder or the like, extrusion molding, and containing the light diffusing agent PC resin pellets are prepared.
In addition, when it contains other various additives, such as a ultraviolet absorber, a flame retardant, and a fluorescent whitening agent, what is necessary is just to mix these additives with a light-diffusion agent at the time of the said pellet preparation.

Next, the light diffusing agent-containing PC resin pellets thus obtained together with a predetermined amount of phosphorescent phosphors, for example, saturated hydrocarbon oils, unsaturated hydrocarbon oils, vegetable oils such as intermediate to higher fatty acids, animal oils, minerals, etc. After adding the oil which consists of 1 type or multiple types of oil, these are mixed, it is melt-kneaded with an extruder etc. at cylinder temperature 235-250 degreeC, and it extrusion-molds, and manufactures a pellet-form PC resin compound. At this time, the screw rotation speed of the extruder is preferably set to be higher than that in general extrusion molding.
The rotational speed at this time improves the kneading of the PC resin pellet containing the light diffusing agent and other additives (hereinafter, the PC resin pellet containing the light diffusing agent) and the phosphorescent phosphor and the remelted state of the pellet. Therefore, in order to evaporate most of the coexisting oil during this kneading and remelting (hereinafter sometimes simply referred to as “kneading”), it is preferably about 15 to 35 rpm. If it is faster than this, not only kneading of the PC pellet and phosphorescent phosphor, but also the transpiration of the oil does not proceed to the desired level, and even if it is slower than this, not only these actions are saturated, but also the time for the re-pelletizing process. This increases the manufacturing cost.

  The amount of the oil used in the present invention is desirably such that it covers the entire surface of each PC resin pellet containing a light diffusing agent, and generally 0.1 to 0.1% of the amount (weight) of the pellet. 5% by weight is suitable. If it is less than this, the phosphorescent phosphor particles are difficult to uniformly adhere to the entire surface of the pellet, and if it is more than this, the pellet will idle in the cylinder and the resin cannot be fed. In the course of kneading the phosphorescent phosphor and in the course of pelletization by extruding the kneaded product, the oil may not sufficiently evaporate, and a sticky feeling may remain in the molded body made of the pellet as well as the pellet. .

As described above, a pellet PC compound containing a light diffusing agent and a stimulable phosphor as essential components can be obtained .
If this compound, that is, the pellet of the present invention is used as a raw material for molding and is extrusion molded at 235 to 260 ° C. or injection molded at 240 to 280 ° C., the pellet of the present invention is used as a material to form a lamp cover or the like. You can get a body .

In the present invention, the phosphorescent phosphor particles are evenly attached to each of the PC resin pellet lumps by interposing oil at the grain interface between the PC resin pellets containing the light diffusing agent and the phosphorescent phosphor. In addition, since the lubricity is improved by the coexisting oil, it is hardly affected by friction and heat deterioration in the molding machine when re-pelletized after kneading, and the light diffusing agent is contained in the PC resin pellet before re-pelletizing. Is contained in advance in a pellet-shaped phosphorescent phosphor-containing PC resin compound obtained by re-pelletizing, that is, a pellet obtained by the production method of the present invention , and a molded product of this pellet ( PC resin compound ). Some lamp covers or the like are not blackened, darkened, or have a fading color, and a decrease in light transmittance is suppressed.

The raw materials used in the following examples and comparative examples are as follows.
(A) Polycarbonate resin: Aromatic polycarbonate resin synthesized from bisphenol A and phosgene (molecular weight 27000-28000, melting point 240 ° C., MVR 7 cm ³ / min.) 100 parts by weight (b) Storage phosphor: Sr ₄ Al ₁₄ O 25: Eu , Dy 7.5 parts by weight (c) Light diffusing agent: calcium carbonate 1.5 parts by weight (d) UV absorber: benzophenone 1 part by weight (e) Flame retardant: phosphorus flame retardant 3.5 parts by weight (f ) Oil: Oil blended with saturated hydrocarbon oil / vegetable oil / higher fatty acid (“SANYO SPREDER N-22” manufactured by Sanyo Chemical Co., Ltd.) 0.5 parts by weight with respect to the amount of PC resin pellet containing light diffusing agent

[Example 1]
After mixing the raw materials of the above (a), (c), (d), and (e), the mixture is kneaded using an extrusion molding machine, extruded, and contains the light diffusing agent. Resin pellets were produced.
Next, after the PC resin pellets of Example 1 and the raw materials (b) and (f) were put into a tumbler and mixed, they were kneaded by an extruder at 250 ° C. and a screw rotation speed (25 rpm). The stimulable phosphor-containing pellet-like PC resin compound of Example 1 (that is, the stimulable phosphor-containing PC resin pellet of the present invention) of Example 1 was produced.
The resulting PC-compound containing stimulable phosphors has a milky white color, and has a smooth surface with no stickiness. Therefore, most of the oil is evaporated during kneading and re-pelletizing. I understand.
This pellet-shaped resin compound was kneaded at 260 ° C. at a screw rotation speed (12 rpm) by an extrusion molding machine and extruded to produce a shape lamp cover shown in FIG. 1 having a thickness of 0.8 mm.

Further, using the above stimulable phosphor-containing pellets PC resin compound, the injection molding machine, the thickness of 0.8 mm, to produce a lamp cover having a shape shown in FIG.

[Comparative Example 1]
After mixing the raw materials (a), (b), (c), (d), and (e) with a blender, they are kneaded with an extruder at 250 ° C. and a screw rotation speed (25 rpm), and extruded. Molding was performed to produce the stimulable phosphor-containing pellet-shaped PC resin compound of Comparative Example 1 .
The resulting stimulable phosphor-containing pellet-like PC resin compound had a smooth surface and no stickiness, but blackening was observed throughout the pellet.
This stimulable phosphor-containing pellet-shaped PC resin compound was extruded under the same conditions as in Example 1 using an extruder, and the lamp of Comparative Example 1 having a thickness of 0.8 mm and having the shape shown in FIG. A cover was manufactured.

[Comparative Example 2]
The same as Comparative Example 1 except that the raw materials (a), (b), (d), (e), and (f) are used (however, the amount of (f) is (a), (b) , (D), (e) 0.5 wt% with respect to the total amount), the stimulable phosphor-containing pellet-shaped PC resin compound of Comparative Example 2 was produced.
In the obtained stimulable phosphor-containing pellet-like PC resin compound, in addition to the fact that the entire pellet had a solid surface feeling, blackening was observed over the entire pellet as in Comparative Example 1.
Using this pellet-shaped PC resin compound, extrusion molding was performed under the same conditions as in the example to produce a lamp cover of Comparative Example 2 having a thickness of 0.8 mm and having the shape shown in FIG.

[Comparative Example 3]
A stimulable phosphor-containing pellet-like PC resin compound of Comparative Example 3 was produced in the same manner as in Example 1 except that the raw material (f) was not used.
As in the case of Comparative Example 1, the obtained stimulable phosphor-containing pellet-like PC resin compound did not have a sticky feeling, but darkening and color unevenness were observed throughout the pellet.
Using this pellet-shaped PC resin compound, extrusion molding was carried out under the same conditions as in Example 1 to produce a lamp cover of Comparative Example 3 having a thickness of 0.8 mm and having the shape shown in FIG.

[Comparative Example 4]
The raw materials (a) to (f) are the same as in Example 1 except that the raw materials are kneaded by the extrusion molding machine used in the cover molding machine of Example 1 and extruded (however, the amount of (f) is As in Comparative Example 2, a lamp cover of Comparative Example 4 having a thickness of 0.8 mm and having the shape shown in FIG. 1 was produced.

[Evaluation of lamp cover]
Regarding Example 1 and Comparative Examples 1 to 4 manufactured as described above, (1) Presence / absence (degree) of blackening of the stimulable phosphor-containing pellet-shaped PC resin compound (in Table 1, material), (2 (1) Presence or absence (degree) of blackening of the molded lamp cover, (3) Illuminance reduction rate when the lamp cover is mounted on the outer surface of the fluorescent lamp tube, and (4) Afterglow luminance was evaluated. The evaluation method for each evaluation item is as follows.

(1) Presence / absence (degree) of blackening of the material pellets: x where the blackened portion and overall darkening are clearly recognized x, and where the blackening and color unevenness are slightly observed overall A clean milky white one was marked with a circle.
(2) Presence / absence (degree) of blackening of fluorescent lamp cover (molded product): Visual observation was performed and evaluation was performed in the same manner as in (1) above.
(3) Illuminance reduction rate by the fluorescent lamp cover: Using a luminometer (FUGI I, DEGIAL LUX METER LX-1010B) on a plane 3 m away from the lit fluorescent lamp (40 W, straight tube type D65) The illuminance [I ₀ ] and the illuminance [I] on the plane when each lamp cover is mounted on the lamp are respectively measured, and the measured value is expressed by the equation {1-([I] / [I ₀ ])} X100 (%) was applied, and the obtained value was defined as the illuminance reduction rate of the fluorescent lamp cover.
(4) Afterglow intensity of the fluorescent lamp cover (afterglow brightness): The fluorescent lamp (40 W, straight tube type D65) equipped with the lamp cover is continuously turned on for 60 minutes, then turned off, and immediately after the lamp is turned off, 3 m away from the lamp cover. The luminance [I _P30 ] on the plane was measured with a luminance meter (KONIKA MINOLTA, LS-100).
The evaluation results of the above (1) to (5) are shown in Table 1.

As can be seen from the results shown in Table 1, the engagement Ru Embodiment 1 of the present invention, no blackening or darkening, etc., exhibited a uniform milky, low lamp cover decrease in light transmittance can be provided.

In contrast, Comparative Examples 1 and 3 in which no oil coexists when mixing the PC resin pellets and the phosphorescent phosphor, Comparative Example 2 in which the oil coexists but does not contain a light diffusing agent, or all the raw materials at once. In Comparative Example 4 in which the mixture is kneaded and extruded , the lamp cover, which is an example of a molded article made of the pellets, as well as the pellets, is blackened or grayish black as a whole, and the lamp cover has a large decrease in light transmittance. Become.

[Example 2 ]
The composition of the raw materials used in the above Examples and Comparative Examples was as follows, and Example 1 except that the screw rotation speed during kneading of the light diffusing agent-containing PC resin pellet and the stimulable phosphor was 35 rpm. In the same manner as above, the pellet of the present invention was manufactured, and a lamp cover as an example of a molded product was manufactured using the pellet as a raw material .
As a result of performing the same evaluation as that obtained in Example 1 on the obtained lamp cover, it was confirmed that the same performance as that obtained in Example 1 was exhibited.
(A) Polycarbonate resin: 100 parts by weight (b) Storage phosphor: 3 parts by weight (c) Light diffusing agent: 0.1 part by weight (d) Ultraviolet absorber: 1 part by weight (e) Flame retardant: 5 parts by weight (f) oil: 0.1 parts by weight with respect to the amount of light diffusing agent-containing pellets

Example 3
A lamp which is an example of a molded product using the pellets of the present invention as a raw material in the same manner as in Example 2 except that the composition of the raw materials used in the above Examples and Comparative Examples is as follows. A cover was manufactured.
As a result of evaluating the obtained lamp cover in the same manner as that obtained in Examples 1 and 2, it was confirmed that the same performance as that obtained in Examples 1 and 2 was exhibited. However, although the afterglow luminance maintained a high value for a long time (about 10 hours), the illuminance reduction rate when the lamp was lit showed a value slightly exceeding 20%.
(A) Polycarbonate resin: 100 parts by weight (b) Storage phosphor: 30 parts by weight (c) Light diffusing agent: 10 parts by weight (d) Ultraviolet absorber: 1 part by weight (e) Flame retardant: 3.5 parts by weight Part (f) oil: 5 parts by weight based on the amount of the light diffusing agent-containing pellet

The pellets of the present invention are beautiful and uniform milky white without darkening or blackening, and are extremely useful as a material for molding molded articles such as lamp covers.
In addition, for example, a lamp cover molded using the pellets of the present invention is not blackened or blackened, but also has excellent mechanical strength and transparency because it is a molded body made of PC resin, and the light source itself, By attaching to the bulb surface of the lighting lamp and using it, it is possible to prevent damage to the lamp due to external impact, and even if it breaks, the broken pieces are prevented from scattering, and a phosphorescent phosphor is contained inside the cover. Since the lamp cover continues to emit light even when the illumination lamp is turned off due to a sudden power failure or the like, it can be used for crime prevention light and evacuation guide light in addition to general indoor illumination light.

1, 11 ...... Lamp cover 2, 12 ...... Opening part 3, 13 ...... Bending part 4, 14 ...... Lighting lamp 15 ............ Connector part 6, 16 ...... Lamp mounting fixture

Claims (2)

A lamp cover that is used by being mounted on the light source of a lighting lamp or the outer surface of a tube,
It consists of a polycarbonate resin molded body containing a phosphorescent phosphor and a light diffusing agent,
The decrease rate of illuminance when the lamp cover having a thickness of 0.8 mm is used for the lamp is 20% or less when the lamp cover is not used.
A lamp cover characterized by that.   A step (A) of obtaining a pellet-like polycarbonate resin compound by kneading a polycarbonate resin pellet containing a light diffusing agent and a phosphorescent phosphor in the presence of oil and extrusion molding at 235 to 250 ° C., and the step ( The method for producing a lamp cover according to claim 1, further comprising a step (B) of extruding the polycarbonate resin compound obtained in A) at 235 to 260 ° C or injection molding at 240 to 280 ° C. .