JPH1017761A - Light diffusion board of polycarbonate resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a light diffusion board of polycarbonate resin exhibiting an excellent light diffusion propertiy color tone and surface properties by melting and extruding a resin obtained by blending specific amounts of micro particles of an infusible acrylic polymer, titanium oxide and a silicone compound respectively. SOLUTION: This light diffusion board of polycarbonate resin includes (A) 10-100g micro particles of an infusible acrylic polymer, (B) 0.12-1.2g titanium oxide and (C) 0.0012-0.5g silicone compound based on 1m<2> polycarbonate resin board with 1-10mm thickness. The component C is preferably a silicone compound of the formula [R1 is methyl or ethyl; R2 is a 1-3C alkyl; R3 is a 1-3C alkyl, etc.; (n) is 2 or 3; (m) is 1 when (n) is 2, or 0 when (n) is 1]. The resin composition having before blending quantities is formed into the objective board shape having a prescribed thickness by a melt-extrusion method. The obtained board can be formed into a milk white board suitable for a skylight out of doors or a lighting fixture.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a light diffusion plate made of polycarbonate resin. More specifically, the present invention relates to a polycarbonate resin white light diffusion plate having excellent light diffusion function, color tone, surface property and impact strength.

[0002]

2. Description of the Related Art Polycarbonate resins have been used in a wide range of fields because of their excellent transparency and impact strength. For example, Sky Dome, Top Light, Arcade,
It is also used in large quantities in the building field, such as apartment lumbar boards and road side walls. Many of these uses are used as white light diffusing plates. Conventionally, white light diffusing plates made of polycarbonate resin (hereinafter referred to as milky white plates) are made of polycarbonate resin, such as calcium carbonate, barium sulfate, silicon oxide, and titanium oxide. A diffusing agent was added and mixed, melt-extruded into a sheet by an extruder equipped with a T-die, and sandwiched and pressed by at least one pair of mirror-surface cooling rolls.
No. 24816). However, the milky white plate obtained by this method has a problem in appearance such that the surface of the milky white plate tends to be non-uniform due to the aggregation of the added light diffusing agent, and irregularities of various sizes are observed.

[0003] For this reason, organic fine particles of a crosslinked polymer have been studied as a light diffusing agent which is hard to aggregate. For example, in a method of adding and mixing fine particles of a crosslinked polymer having a different refractive index from that of a polycarbonate resin (Japanese Patent Publication No. 39-10515), although a milky white plate having a uniform surface and little unevenness is obtained, it exhibits a yellowish color and a color tone. No good milky plate has been obtained. Also, a method has been proposed in which partially crosslinked polymer fine particles are added to and mixed with a polycarbonate resin (JP-A-3-143950). However, the milky white plate obtained by this method was also strongly yellowish. Further, a light diffusing agent comprising fine particles containing titanium oxide and polymer particles having an alkyl acrylate polymer or an alkyl methacrylate polymer having a core / shell monomorphy including a core and a shell of a rubbery vinyl polymer. Compositions have been proposed (JP-A-7-14).
No. 9995). However, the milky white plate obtained by adding this light diffusing agent composition to the polycarbonate resin also had a yellowish tint. As a method of obtaining a milky white plate having a good color tone, a method of mixing a silicon compound with titanium oxide has been proposed (JP-A-5-329998). However, the milky white plate obtained by this method has a problem that the light diffusion effect is not sufficient and the light source can be seen through.
As described above, no milky white plate made of a polycarbonate resin satisfying all of the light diffusion function, color tone, and surface properties has been obtained.

[0004]

An object of the present invention is to provide a milky white plate made of a polycarbonate resin having excellent light diffusion performance, color tone, surface properties and impact strength, especially a polycarbonate resin suitable for outdoor lighting and lighting equipment. To provide a low-cost milky white plate made of aluminum.

The inventor of the present invention has conducted intensive studies in order to achieve the above object, and as a result, obtained a milky white plate obtained by melt-extruding a polycarbonate resin containing a specific amount of an infusible acrylic polymer fine particle, titanium oxide and a silicon compound. Have found that excellent light diffusion performance, color tone, surface properties and impact strength can be obtained, and have completed the present invention.

[0006]

The present invention SUMMARY OF] is a thickness of a polycarbonate resin plate 1 to 10 mm, and the 10~100g to the polycarbonate resin plate 1 m ² per infusible acrylic polymer fine particles, 0 The present invention relates to a polycarbonate resin light diffusion plate containing 0.12 to 1.2 g of titanium oxide and 0.0012 to 0.5 g of a silicon compound.

The polycarbonate resin used in the present invention is an aromatic polycarbonate resin obtained by reacting a dihydric phenol with a carbonate precursor. The dihydric phenol used here is mainly 2,2-bis (4-hydroxyphenyl) propane (commonly known as bisphenol A), but a part or all of the dihydric phenol may be replaced with another dihydric phenol. Other dihydric phenols include, for example, 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) ) Propane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfonic acid and the like. Examples of the carbonate precursor include phosgene, bischloroformate of the above-mentioned dihydric phenols, diphenyl carbonate, di-p-
Examples thereof include tolyl carbonate, di-p-chlorophenyl carbonate, and dinaphthyl carbonate. Among them, phosgene and diphenyl carbonate are most preferred.

The molecular weight of the polycarbonate resin is usually from 15,000 to 40,000, preferably from 18,000 to 35,000, expressed as a viscosity average molecular weight. In producing such a polycarbonate resin, a suitable molecular weight modifier, a catalyst for accelerating the reaction, a branching agent for improving processability, and, if necessary, for example, stabilizing a phosphite, a phosphate, a phosphonate, etc. Agents, flame retardants, release agents, coloring agents, ultraviolet absorbers and the like can be added.

The thickness of the polycarbonate resin plate of the present invention is 1 to 10 mm. If the thickness is less than 1 mm, the rigidity is insufficient, so that it is not appropriate. If the thickness is more than 10 mm, it is not practical in terms of weight.

The infusible acrylic polymer fine particles used in the present invention are at least partially cross-linked in the production process, do not substantially deform during the processing of the polycarbonate resin, and maintain the fine particle state. Is what it is. That is, the molding temperature of the polycarbonate resin (350
(C) even if heated to (° C). As preferable examples thereof, for example, polymer fine particles based on partially cross-linked methyl methacrylate [MBX-5, MBX-8, M manufactured by Sekisui Chemical Co., Ltd.]
BX-20, MBX-50], a polymer having a poly (butyl acrylate) core / poly (methyl methacrylate) shell, a polymer having a core / shell monomorphy including a rubbery vinyl polymer core and shell [ROHM And Haas Company, product name Paraloid EXL-5136]. The particle size of the infusible acrylic polymer fine particles is preferably in the range of 5 to 50 μm. The particle size of the fine particles is a weight distribution average particle size measured by a Coulter counter method, and the measuring device is a particle number / particle size distribution analyzer MODELZm manufactured by Nikkaki Co., Ltd.
It is. From the viewpoint of light diffusion performance, the effect is small even if it deviates from 5 to 50 μm, but the particle size is smaller than 5 μm or 50 μm.
If it exceeds μm, it is not preferable because the bite of the screw tends to become unstable when melt-extruded after being added to and mixed with the polycarbonate resin. The amount of infusible acrylic polymer microparticles are polycarbonate resin plate 1 m ² per 10~100g thickness 1 to 10 mm. If the amount is less than 10 g, it is difficult to obtain a sufficient light diffusing property, and if the amount is more than 100 g, the light diffusing effect is saturated and no longer improves.

The titanium oxide used in the present invention may be any titanium oxide, but titanium oxide produced by a chlorine method in view of the whiteness of the milky white plate obtained and a hydrated oxide of aluminum and silicon Are preferred. Here, representative examples of the hydrated oxide of aluminum and silicon used for the surface treatment of titanium oxide include alumina and silica. The mixing ratio of alumina and silica is 10 to 1 for 100 parts by weight of alumina.
A range of 00 parts by weight is suitable. The amount of titanium oxide used is 1 m ^{2 of} a polycarbonate resin plate having a thickness of 1 to 10 mm.
0.12 to 1.2 g per weight. If the amount is less than 0.12 g, it is difficult to obtain a sufficient milky white plate. If the amount is more than 1.2 g, the concealing power increases, and the effect as a light diffusing plate is reduced.

Further, by using a silicon compound together with titanium oxide, a vivid milky white plate which has never been seen before can be obtained. The silicon compound has the following general formula

[0013]

Embedded image

[Wherein R ₁ is a methyl group or an ethyl group, R ₂
Is an alkyl group having 1 to ₃ carbon atoms, R ₃ is an alkyl group having 1 to ₃ carbon atoms or —R ₄ NHR ₅ (where R ₄ is an ethylene group or a propylene group, R ₅ is a hydrogen atom or an aminoethyl group), n Is 2 or 3, and m is 1 when n is 2 and 0 when n is 1. Particularly preferred silicon compounds are methyltrimethoxysilane, dimethyldimethoxysilane, and ethyl. Trimethoxysilane, propyltrimethoxysilane, γ-aminopropyltriethoxysilane, N (β-aminoethyl) -γ-
Aminopropyltrimethoxysilane, N (β-aminoethyl) -γ-aminopropylmethyl-dimethoxysilane and the like. The amount of silicon compound used is 1 to 10 m in thickness
a polycarbonate resin plate 1 m ² per m 0.0012～
0.5 g. If the amount is less than 0.0012 g, a milky white plate tends to be formed, and if the amount is more than 0.36 g, a bright milky white color reaches equilibrium and the effect becomes saturated.

The polycarbonate resin composition obtained by mixing the above-mentioned necessary components in a predetermined amount is formed into a plate having a predetermined thickness by a conventional method, usually by a melt extrusion method. When performing melt extrusion, the melting zone of the extruder is set to 10 to 500
It is preferable to extrude under reduced pressure of mmHg. When the melting zone of the extruder is not reduced in pressure, the compounded infusible acrylic polymer fine particles are affected by oxygen, and the surface of the particle size may be partially collapsed and light diffusion performance may be reduced. .

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be further described below with reference to examples. The evaluation items and methods are as follows. (1) Color Tone: Observed visually, ◎ indicates a bright white color, ○ indicates a slightly yellowish white color, and × indicates a yellowish dull white color. (2) Hue: color machine [Z-made by Nippon Denshoku Industries Co., Ltd.
100 DP]. (3) Total light transmittance: according to JIS K-6735. T. It is indicated by a value measured by an R meter [integrating sphere light transmittance measuring device manufactured by Nippon Seimitsu Kogyo KK] (C light source). (4) Impact strength: AST using a 3 mm thick resin plate
The value was measured (kgf · cm / cm) of Izod impact strength according to MD-790 (with notch). (5) Surface properties: Observed by visual observation, ◎ indicates that the surface is mirror-like, ○ indicates that the surface is slightly uneven, and X indicates that the surface is significantly noticeable. (6) Relative diffuse transmitted light amount: As shown in FIG. 1, a light source and a light receiving section were provided with a test piece interposed therebetween, and light energy transmitted through the test piece was measured by the light receiving section. A variable angle gloss meter VG-1B manufactured by Nippon Denshoku Industries Co., Ltd. was used as a measuring instrument. The measured value when the light receiving angle θ is 0 ° is 100%, and the light receiving angle is 5%.
°, 10 °, 20 °, 30 °, 40 °, 50 °, 60
° and 70 °, and the results were evaluated as ◎ when the light diffusion performance was good, ○ when the light diffusion performance was slightly low, and × when the light diffusion performance was low. 2, 3, and 4 show the relative angle distribution of the light of ◎, 、, and ×.

Examples 1 to 3, Comparative Examples 1 to 5 Viscosity average molecular weights obtained from bisphenol A and phosgene 24, 30
A 300 kg of polycarbonate resin of No. 0 was prepared in an infusible acrylic polymer fine particle [EXL-51 manufactured by Rohm and Haas Company] in a weight adjusted to the amount described in Table 1.
36, weight distribution average particle diameter 7 μm], titanium oxide [CR-60 manufactured by Ishihara Sangyo Co., Ltd.] and silicon compound [methyltrimethoxysilane, KBM-13 manufactured by Shin-Etsu Silicone Co., Ltd.]
Are mixed in advance and mixed, and the cylinder diameter 90
mm vented T-die extruder, extruder temperature 26
0 to 300 ° C., die temperature 260 to 300 ° C., the degree of vacuum at the vent is maintained at 200 mmHg, and the thickness is 3 mm and the width is 1.
A 000 mm polycarbonate resin light diffusion plate was melt extruded, and the evaluation results of the obtained diffusion plate are shown in Table 1.

[0018]

[Table 1]

[0019]

The polycarbonate resin plate of the present invention is excellent in light diffusion function, color tone, surface properties and impact strength.
It is very suitable as a white light diffusion plate.

[Brief description of the drawings]

FIG. 1 is a simplified diagram of an apparatus used for measuring a relative diffuse transmission light amount.

FIG. 2 is a graph showing the relative angle distribution of light indicated by ◎ with good light diffusion performance.

FIG. 3 is a diagram showing a relative angle distribution of light having a slightly lower light diffusion performance.

FIG. 4 is a diagram showing a relative angle distribution of X light having low light diffusion performance.

[Explanation of symbols]

 1 Test piece 2 Light source 3 Receiver

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location C08L 33:00)

Claims (3)

[Claims] The thickness of a polycarbonate resin plate is 1 to 1
0 mm, and 1 m ^{2 of the} polycarbonate resin plate.
Per 100 to 100 g of infusible acrylic polymer fine particles, 0.12 to 1.2 g of titanium oxide and 0.0012
A light diffusion plate made of a polycarbonate resin, which contains 0.5 to 0.5 g of a silicon compound. 2. The polycarbonate resin light diffusion plate according to claim 1, wherein the infusible acrylic polymer fine particles have an average particle size of 5 to 50 μm. 3. A silicon compound represented by the following general formula: Wherein R ₁ is a methyl group or an ethyl group, and R ₂ is
3 alkyl groups, R ₃ is an alkyl group having 1 to ₃ carbon atoms or —R ₄ NHR ₅ (where R ₄ is an ethylene group or a propylene group, R ₅ is a hydrogen atom or an aminoethyl group), n is 2 or 3, m is 1 when n is 2 and 0 when n is 1.
The polycarbonate resin light diffusion plate according to claim 1 or 2, which is a silicon compound represented by the following formula: