JP3669111B2 - Resin composition for lighting cover and lighting cover comprising the same - Google Patents

Description

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【表２】

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【表３】

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【発明の効果】
本発明の照明カバー用樹脂組成物は、ポリカーボネート樹脂の特徴である透明性、耐熱性、機械的性質を保持するとともに、照明カバーとして長期間使用されても黄変や加水分解に基づく穿孔等を防止することができる。[0001]
[Industrial application fields]
TECHNICAL FIELD The present invention relates to a lighting cover resin composition excellent in hydrolysis resistance and heat discoloration resistance and a lighting cover comprising the same.
[0002]
[Prior art]
Conventionally, glass, acrylic resin, polycarbonate resin or the like is used for the lighting cover. Glass lighting covers have problems of safety when damaged due to impact, etc., and are also heavy due to their relatively high specific gravity. Recently, replacement with transparent plastic materials such as acrylic resin and polycarbonate resin has been actively performed. ing.
[Problems to be solved by the invention]
[0003]
In particular, polycarbonate resins are excellent in transparency, impact resistance, heat resistance, and the like, and thus are increasingly used as lighting covers. However, polycarbonate resins have the disadvantage of yellowing or hydrolysis when exposed to high temperature and humidity for a long period of time. When placed, there was a problem that the lighting cover discolored (yellowing) or a hole opened by hydrolysis.
[0004]
In order to compensate for such drawbacks of the polycarbonate resin, for example, the amount of impurities in the polycarbonate resin is regulated (Japanese Patent Laid-Open No. 4-2222829), or when the light diffusing agent is blended, the surface of the light diffusing agent is deactivated. For this reason, methods such as surface treatment (JP-A-6-107939 and JP-A-8-104801) have been proposed, but they have not yet been completely solved.
[0005]
[Means for Solving the Problems]
As a result of diligent study to solve the above-mentioned problems, the present inventors have found that the inorganic and organic components of moisture adhering to the lighting cover after installing the lighting fixture, the detergent used at the time of cleaning, etc. of the polycarbonate resin lighting cover. It was found that it was the cause of yellowing and perforation due to hydrolysis.
[0006]
Based on this knowledge, the present inventors mixed a specific thermoplastic resin with a polycarbonate resin for a lighting cover, so that the thermoplastic resin component was selectively oriented in the surface layer part during molding, and polycarbonate To prevent perforation due to yellowing or hydrolysis during long-term use, which is the aforementioned problem of polycarbonate resin lighting covers, without substantially sacrificing the transparency, heat resistance, and mechanical properties of the resin. As a result, the present invention has been completed.
[0007]
That is, the present invention provides a lighting cover resin composition comprising 100 parts by weight of a polycarbonate resin (A) and 2 to 90 parts by weight of another thermoplastic resin (B), wherein the thermoplastic resin (B) is: The present invention provides a resin composition for a lighting cover, which satisfies all the conditions (3) to (3), and a lighting cover comprising the same.
(1) The difference in refractive index from the polycarbonate resin (A) is 0.03 or less.
(2) The ratio of melt viscosity with the polycarbonate resin (A) satisfies the following formula.
Vb / Va ≦ 0.6
(Vb: melt viscosity of thermoplastic resin (B))
(Va: Melt viscosity of polycarbonate resin (A))
(3) The difference in solubility parameter from the polycarbonate resin (A) is in the range of 0.2 to 1.0.
[0008]
Below, it demonstrates in detail about the resin composition for lighting covers of this invention.
[0009]
The polycarbonate resin (A) used in the present invention is obtained by a phosgene method in which various dihydroxydiaryl compounds and phosgene are reacted, or a transesterification method in which a dihydroxydiaryl compound and a carbonate such as diphenyl carbonate are reacted. A typical example of the polymer is a polycarbonate resin produced from 2,2-bis (4-hydroxyphenyl) propane (bisphenol A).
[0010]
Examples of the dihydroxydiaryl compound include bisphenol 4-, bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) butane, 2, 2-bis (4-hydroxyphenyl) octane, bis (4-hydroxyphenyl) phenylmethane, 2,2-bis (4-hydroxyphenyl-3-methylphenyl) propane, 1,1-bis (4-hydroxy-3) -Tert-butylphenyl) propane, 2,2-bis (4-hydroxy-3-bromophenyl) propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis ( Bis (hydroxyaryl) alkanes such as 4-hydroxy-3,5-dichlorophenyl) propane, 1,1- (4-hydroxyphenyl) cyclopentane, bis (hydroxyaryl) cycloalkanes such as 1,1-bis (4-hydroxyphenyl) cyclohexane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3 Dihydroxy diaryl ethers such as 3,3'-dimethyldiphenyl ether, dihydroxy diaryl sulfides such as 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxy-3,3 ' Dihydroxy diaryl sulfoxides such as dimethyldiphenyl sulfoxide, dihydroxy diary such as 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone Sulfone, and the like.
[0011]
These may be used alone or in combination of two or more. In addition to these, piperazine, dipiperidyl hydroquinone, resorcin, 4,4'-dihydroxydiphenyl, and the like may be used in combination.
[0012]
Furthermore, the above dihydroxyaryl compound and a trivalent or higher valent phenol compound as shown below may be used in combination.
[0013]
Trihydric or higher phenols include phloroglucin, 4,6-dimethyl-2,4,6-tri- (4-hydroxyphenyl) -heptene, 2,4,6-dimethyl-2,4,6-tri- (4 -Hydroxyphenyl) -heptane, 1,3,5-tri- (4-hydroxyphenyl) -benzol, 1,1,1-tri- (4-hydroxyphenyl) -ethane and 2,2-bis- [4 4- (4,4'-dihydroxydiphenyl) -cyclohexyl] -propane and the like.
[0014]
The viscosity average molecular weight of the polycarbonate resin (A) is usually 10,000 to 100,000, preferably 15,000 to 35,000. In producing such a polycarbonate resin (A), a molecular weight regulator, a catalyst and the like can be used as necessary.
[0015]
The thermoplastic resin (B) used in the present invention is not particularly limited as long as it is a thermoplastic resin other than a polycarbonate resin that satisfies all of the following conditions, but polystyrene (PS), acrylonitrile / styrene resin (AS) Resin), styrene / maleic anhydride resin (SMA resin), polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and the like are preferably used. These may be used alone or in combination of two or more.
(1) The difference in refractive index from the polycarbonate resin (A) is 0.03 or less.
(2) The ratio of melt viscosity with the polycarbonate resin (A) satisfies the following formula.
Vb / Va ≦ 0.6
(Vb: melt viscosity of thermoplastic resin (B))
(Va: Melt viscosity of polycarbonate resin (A))
(3) The difference in solubility parameter from the polycarbonate resin (A) is in the range of 0.2 to 1.0.
[0016]
The above refractive index is a value measured by ASTM D-542, and if the refractive index difference exceeds 0.03, the transparency is lowered, which is not preferable as a lighting cover.
[0017]
The melt viscosity is a capillary flow viscosity at 280 ° C., which is a value when the shear rate is 1 × 1000 sec−1. When the melt viscosity ratio exceeds 0.6, the thermoplastic resin (B) is converted into a polycarbonate resin ( It is not preferable because it is easy to disperse uniformly in A).
[0018]
Further, the solubility parameter is a value obtained from the following equation. When the difference in solubility parameter is less than 0.2, the thermoplastic resin (B) is easily compatible with the polycarbonate resin (A), and If it exceeds 0, delamination tends to occur during molding, which is not preferable.
Solubility parameter (δ) = (ΣFi) / V = (σΣFi) / M
Fi: molar traction force of atoms, atomic groups, bond groups, etc. constituting the molecule V: molar volume σ: density M: molecular weight of the repeating unit of the resin
The usage-amount of a thermoplastic resin (B) is 2-90 weight part with respect to 100 weight part of polycarbonate resin (A). If it is less than 2 parts by weight, yellowing and perforation are insufficiently prevented, and if it exceeds 90 parts by weight, the heat resistance is remarkably lowered. A more preferable use amount is in the range of 5 to 40 parts by weight.
[0020]
There is no restriction | limiting in particular in the mixing method of polycarbonate resin (A) and a thermoplastic resin (B), The method of mixing by a well-known mixer, for example, a tumbler, a ribbon blender, a high-speed mixer etc., is mentioned.
[0021]
Furthermore, various additives such as a light diffusing agent, an antioxidant, an antistatic agent, a release agent, a lubricant, a light stabilizer, an ultraviolet absorber, and a dye / pigment may be added at the time of mixing within a range not impairing the effects of the present invention. You may mix | blend as needed.
[0022]
Although there is no restriction | limiting in particular in the use of the lighting cover obtained by this invention, It uses suitably for the lighting fixture placed in a hot and humid environment for a long period of time. For example, a glove for a bathroom lamp, an outdoor lighting device such as a glove for a street light, a cover for a vehicle lamp, and the like.
[0023]
【Example】
EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. “Parts” and “%” are based on weight standards.
[0024]
(Examples 1-7 and Comparative Examples 1-6)
Various thermoplastic resins per 100 parts of polycarbonate resin (viscosity average molecular weight 21000, Caliber 200-13 manufactured by Sumitomo Dow Co., Ltd.) were premixed with a tumbler based on the blending ratios in Table 1 (Example) and Table 2 (Comparative Example). These were melt-mixed with a single screw extruder to obtain pellets of various resin compositions.
[0025]
Using the obtained pellets of various resin compositions, a 150 × 90 × 2 mm plate was formed by injection molding and used for the test. The test results are shown in Table 3. The test items and their evaluation methods are as follows:
[0026]
transparency:
The obtained test piece was visually determined. The evaluation criteria are as follows:
◎: Transparent ○: Translucent ×: Devitrification [0027]
Compatibility:
The case where layer peeling was observed at the time of injection molding of the test piece was rated as x, and the case where peeling was not observed was marked as ◯.
[0028]
Heat-resistant:
A test piece was fixed on a jig having a span width of 140 mm, and the presence or absence of deformation due to its own weight after being left in a hot air circulating oven at 130 ° C. for 24 hours was determined. The evaluation criteria are as follows:
◎: No deformation ○: Maximum deformation amount is 0.5 mm or less ×: Maximum deformation amount exceeds 0.5 mm [0029]
Thermochromic and hydrolyzable:
Place a test piece on a hot plate at 140 ° C in a constant temperature and humidity room at 23 ° C and 50% RH, and the total alkalinity specified in the water test method 14.2.1 is about 3 times a day. Ten milliliters of 85CaCO3 mg / l tap water was added dropwise to the test piece, and the surface state of the test piece after 30 days was observed. As the evaluation criteria, no change was indicated as ◯, yellowing and a case where only a dent caused by hydrolysis was detected as x.
[0030]
[Table 1]

[0031]
[Table 2]

[0032]
[Table 3]

[0033]
【The invention's effect】
The resin composition for lighting covers of the present invention retains the transparency, heat resistance and mechanical properties that are characteristic of polycarbonate resins, and even when used as a lighting cover for a long period of time, it does not perforate due to yellowing or hydrolysis. Can be prevented.

Claims (3)

In the resin composition for a lighting cover comprising 100 parts by weight of the polycarbonate resin (A) and 2 to 90 parts by weight of the other thermoplastic resin (B), the thermoplastic resin (B) has the following conditions (1) to (3) The resin composition for lighting covers characterized by satisfying all of the above.
(1) The difference in refractive index from the polycarbonate resin (A) is 0.03 or less.
(2) The ratio of melt viscosity with the polycarbonate resin (A) satisfies the following formula.
Vb / Va ≦ 0.6
(Vb: melt viscosity of thermoplastic resin (B))
(Va: Melt viscosity of polycarbonate resin (A))
(3) The difference in solubility parameter from the polycarbonate resin (A) is in the range of 0.2 to 1.0. The lighting cover according to claim 1, wherein the thermoplastic resin (B) is one or two or more resins selected from polystyrene, acrylonitrile / styrene resin, styrene / maleic anhydride resin, polyethylene terephthalate and polybutylene terephthalate. Resin composition. The lighting cover which consists of the resin composition for lighting covers of Claim 1 or Claim 2.