JP6850204B2 - Polycarbonate resin composition for optical members - Google Patents

Description

The present invention relates to a polycarbonate resin composition for an optical member, and more particularly to a polycarbonate resin composition for an optical member, which is excellent in transparency and has an excellent balance between fluidity and impact resistance.

As the optical member, for example, a light guide plate is used for a lighting unit such as a backlight unit of various display devices. Recently, there is a demand for a display device that displays a clearer image, and the inside of the device tends to become hot due to heat generated in the vicinity of the light source, so that the material is being replaced with a polycarbonate resin material having higher heat resistance.

However, since the conventional polycarbonate resin is inferior in fluidity, when molding a thin and large light guide plate, the thickness in the plane of the light guide plate may be uneven or the microprism structure may be transferred. Has a problem that the transferability on the anti-gate side is particularly poor. In order to improve the fluidity and transferability, there is a method of lowering the molecular weight of the polycarbonate resin, but as the molecular weight is lowered, the mechanical strength is lowered. Therefore, as a material for the light guide plate, a polycarbonate resin having excellent fluidity and mechanical strength is required.

In order to improve the fluidity, a method of mixing polycarbonate resins having different molecular weights has also been proposed (see Patent Document 1). However, simply mixing polycarbonate resins having different molecular weights tends to result in inferior impact resistance.

Further, Patent Document 2 proposes a composition containing 0.01 to 0.5 parts by weight of a silicone resin (B) containing a phenyl group and a silanol group in 100 parts by weight of the polycarbonate resin (A). However, the amount of silicone is too small to obtain the effect of improving impact strength, and since it contains silanol groups, it is inferior in thermal stability. And there is no description about the viscosity, molecular weight, and refractive index of the silicone resin.
Further, Patent Document 3 describes a polyorganosiloxane having at least a phenyl group in the side chain and a branched siloxane structure with respect to 100 parts by weight of the aromatic polycarbonate resin, and has a kinematic viscosity of 1 to 200 cSt at 25 ° C. A composition containing 0.01 to 1 part by weight of the polyorganosiloxane of the above is described. However, in the composition, the amount of silicone is too small to obtain the effect of improving the impact strength.
According to Patent Document 4, the applicant has made a polycarbonate resin composition containing an organic sulfonic acid metal salt and a poly (dimethylsiloxane) -poly (diphenylsiloxane) copolymer having a kinematic viscosity of 1 to 120 centimeters, which is flame-retardant. We proposed that it is excellent in transparency, low gas property, heat aging property, and wet heat stability. However, this composition tends to generate gas during molding and has a problem of mold contamination.
As described above, the fact is that a polycarbonate resin composition for an optical member having excellent transparency and an excellent balance between fluidity and impact resistance has not yet been found.

Japanese Unexamined Patent Publication No. 9-208684 Japanese Unexamined Patent Publication No. 2014-101407 Japanese Unexamined Patent Publication No. 2004-250557 Japanese Unexamined Patent Publication No. 2012-7054

The present invention has been made in view of the above circumstances, and an object (problem) thereof is to provide a polycarbonate resin composition for an optical member having excellent transparency and an excellent balance between fluidity and impact resistance. ..

As a result of diligent studies to achieve the above problems, the present inventor can solve the above problems by blending a specific silicone compound with a specific viscosity average molecular weight aromatic polycarbonate resin in a specific amount. The present invention has been completed.
The present invention relates to the following polycarbonate resin compositions for optical members.

[1] A resin composition containing more than 1 part by mass and 7 parts by mass or less of the silicone compound (B) with respect to 100 parts by mass of the aromatic polycarbonate resin (A) having a viscosity average molecular weight of 12,000 to 16,000. ,
Silicone compound (B), the terminal does not contain silanol groups, a kinematic viscosity of less than 3000 mm ² / sec ultra 50,000 ^mm 2 / sec at 25 ° C., the refractive index at 25 ° C. (nD) is A polycarbonate resin composition for an optical member, which is 1.560 to 1.600 and satisfies the following formula (1).
| NPC-nSi | × νSi ≤ 21 ... (1)
[In the formula, nPC is the refractive index (nD) of the polycarbonate resin (A), nSi is the refractive index (nD) of the silicone compound (B), and νSi is the kinematic viscosity (25 ° C.) of the silicone compound (B). ]
[2] An optical member made of the polycarbonate resin composition according to the above [1].
[3] The optical member according to the above [2], wherein the optical member is a light guide plate.

The polycarbonate resin composition of the present invention has excellent transparency, an excellent balance between fluidity and impact strength, and can be particularly preferably used as various optical members.

FIG. 1 is a graph showing the relationship between fluidity and impact strength in Examples and Comparative Examples. FIG. 2 is a plan view of the drop mold used for the evaluation of transparency in the examples.

Hereinafter, the present invention will be described in detail with reference to embodiments and examples.
In addition, in this specification, "~" is used in the meaning which includes the numerical values described before and after it as the lower limit value and the upper limit value unless otherwise specified.

The polycarbonate resin composition for an optical member of the present invention has a viscosity average molecular weight of 12,000 to 16,000 and is 100 parts by mass of the aromatic polycarbonate resin (A), and more than 1 part by mass of the silicone compound (B) and 7 parts by mass or less. A resin composition containing
Silicone compound (B), the terminal does not contain silanol groups, a kinematic viscosity of less than 3000 mm ² / sec ultra 50,000 ^mm 2 / sec at 25 ° C., the refractive index at 25 ° C. (nD) is It is 1.560 to 1.600 and is characterized by satisfying the following formula (1).
| NPC-nSi | × νSi ≤ 21 ... (1)
[In the formula, nPC is the refractive index (nD) of the polycarbonate resin (A), nSi is the refractive index (nD) of the silicone compound (B), and νSi is the kinematic viscosity (25 ° C.) of the silicone compound (B). ]
Hereinafter, the present invention will be described in detail.

[Aromatic Polycarbonate Resin (A)]
The type of the aromatic polycarbonate resin (A) used in the polycarbonate resin composition of the present invention is not limited, and only one type may be used, and two or more types may be used in any combination and any ratio. It may be used together.
The aromatic polycarbonate resin in the present invention is
A polymer having a basic structure having a carbonic acid bond, represented by a general formula:-[-O-X-OC (= O)-]-. In the formula, X is an aromatic hydrocarbon, but a heteroatom or an X having a heterobond introduced may be used to impart various properties.

The specific type of the aromatic polycarbonate resin is not limited, and examples thereof include an aromatic polycarbonate polymer obtained by reacting an aromatic dihydroxy compound with a carbonate precursor. At this time, in addition to the aromatic dihydroxy compound and the carbonate precursor, a polyhydroxy compound or the like may be reacted. Further, a method of reacting carbon dioxide with cyclic ether using carbon dioxide as a carbonate precursor may also be used. Further, the aromatic polycarbonate polymer may be linear or branched. Further, the aromatic polycarbonate polymer may be a homopolymer composed of one type of repeating unit or a copolymer having two or more types of repeating units. At this time, as the copolymer, various copolymer forms such as a random copolymer and a block copolymer can be selected. Usually, such an aromatic polycarbonate polymer becomes a thermoplastic resin.

Examples of aromatic dihydroxy compounds as raw material monomers of aromatic polycarbonate resins are as follows.
Dihydroxybenzenes such as 1,2-dihydroxybenzene, 1,3-dihydroxybenzene (ie resorcinol), 1,4-dihydroxybenzene;
Dihydroxybiphenyls such as 2,5-dihydroxybiphenyl, 2,2'-dihydroxybiphenyl, 4,4'-dihydroxybiphenyl;

2,2'-Dihydroxy-1,1'-binaphthyl, 1,2-dihydroxynaphthalene, 1,3-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 1 , 7-Dihydroxynaphthalene, 2,7-dihydroxynaphthalene and other dihydroxynaphthalene;

2,2'-Dihydroxydiphenyl ether, 3,3'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether, 1,4-bis (3-hydroxyphenoxy) Dihydroxydiaryl ethers such as benzene and 1,3-bis (4-hydroxyphenoxy) benzene;

2,2-bis (4-hydroxyphenyl) propane (ie, bisphenol A),
1,1-bis (4-hydroxyphenyl) propane,
2,2-bis (3-methyl-4-hydroxyphenyl) propane,
2,2-bis (3-methoxy-4-hydroxyphenyl) propane,
2- (4-Hydroxyphenyl) -2- (3-methoxy-4-hydroxyphenyl) propane,
1,1-bis (3-tert-butyl-4-hydroxyphenyl) propane,
2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane,
2,2-bis (3-cyclohexyl-4-hydroxyphenyl) propane,
2- (4-Hydroxyphenyl) -2- (3-cyclohexyl-4-hydroxyphenyl) propane,
α, α'-bis (4-hydroxyphenyl) -1,4-diisopropylbenzene,
1,3-bis [2- (4-hydroxyphenyl) -2-propyl] benzene,
Bis (4-hydroxyphenyl) methane,
Bis (4-hydroxyphenyl) cyclohexylmethane,
Bis (4-hydroxyphenyl) phenylmethane,
Bis (4-hydroxyphenyl) (4-propenylphenyl) methane,
Bis (4-hydroxyphenyl) diphenylmethane,
Bis (4-hydroxyphenyl) naphthylmethane,
1,1-bis (4-hydroxyphenyl) ethane,
1,2-bis (4-hydroxyphenyl) ethane,
1,1-bis (4-hydroxyphenyl) -1-phenylethane,
1,1-bis (4-hydroxyphenyl) -1-naphthylethane,
1,1-bis (4-hydroxyphenyl) butane,
2,2-bis (4-hydroxyphenyl) butane,
2,2-bis (4-hydroxyphenyl) pentane,
1,1-bis (4-hydroxyphenyl) hexane,
2,2-bis (4-hydroxyphenyl) hexane,
1,1-bis (4-hydroxyphenyl) octane,
2,2-bis (4-hydroxyphenyl) octane,
4,4-bis (4-hydroxyphenyl) heptane,
2,2-bis (4-hydroxyphenyl) nonane,
1,10-bis (4-hydroxyphenyl) decane,
1,1-bis (4-hydroxyphenyl) dodecane,
Bis (hydroxyaryl) alkanes such as;

1,1-bis (4-hydroxyphenyl) cyclopentane,
1,1-bis (4-hydroxyphenyl) cyclohexane,
1,4-Bis (4-hydroxyphenyl) cyclohexane,
1,1-bis (4-hydroxyphenyl) -3,3-dimethylcyclohexane,
1,1-bis (4-hydroxyphenyl) -3,4-dimethylcyclohexane,
1,1-bis (4-hydroxyphenyl) -3,5-dimethylcyclohexane,
1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane,
1,1-bis (4-hydroxy-3,5-dimethylphenyl) -3,3,5-trimethylcyclohexane,
1,1-bis (4-hydroxyphenyl) -3-propyl-5-methylcyclohexane,
1,1-bis (4-hydroxyphenyl) -3-tert-butyl-cyclohexane,
1,1-bis (4-hydroxyphenyl) -4-tert-butyl-cyclohexane,
1,1-bis (4-hydroxyphenyl) -3-phenylcyclohexane,
1,1-bis (4-hydroxyphenyl) -4-phenylcyclohexane,
Bis (hydroxyaryl) cycloalkanes such as;

Cardo-structure-containing bisphenols such as 9,9-bis (4-hydroxyphenyl) fluorene and 9,9-bis (4-hydroxy-3-methylphenyl) fluorene;
Dihydroxydiarylsulfides such as 4,4'-dihydroxydiphenylsulfide, 4,4'-dihydroxy-3,3'-dimethyldiphenylsulfide;
Dihydroxydiarylsulfoxides such as 4,4'-dihydroxydiphenylsulfoxide, 4,4'-dihydroxy-3,3'-dimethyldiphenylsulfoxide;
Dihydroxydiaryl sulfones such as 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone; and the like.

Among these, bis (hydroxyaryl) alkanes are preferable, and bis (4-hydroxyphenyl) alkanes are preferable, and 2,2-bis (4-hydroxyphenyl) propane is particularly preferable from the viewpoint of impact resistance and heat resistance. (Ie, bisphenol A) is preferred.
As the aromatic dihydroxy compound, one type may be used, or two or more types may be used in any combination and ratio.

Among the monomers used as raw materials for aromatic polycarbonate resins, carbonyl halides, carbonate esters and the like are used as examples of carbonate precursors. As the carbonate precursor, one kind may be used, or two or more kinds may be used in any combination and ratio.

Specific examples of the carbonyl halide include phosgene; a bischloroformate of a dihydroxy compound, a haloformate of a monochloroformate of a dihydroxy compound, and the like.

Specific examples of the carbonate ester include diaryl carbonates such as diphenyl carbonate and ditril carbonate; dialkyl carbonates such as dimethyl carbonate and diethyl carbonate; biscarbonate of dihydroxy compound, monocarbonate of dihydroxy compound, and cyclic carbonate. Examples thereof include carbonates of dihydroxy compounds such as.

The method for producing the aromatic polycarbonate resin (A) is not particularly limited, and any method can be adopted. Examples thereof include an interfacial polymerization method, a melt transesterification method, a pyridine method, a ring-opening polymerization method of a cyclic carbonate compound, and a solid phase transesterification method of a prepolymer.

In the present invention, the aromatic polycarbonate resin (A) having a viscosity average molecular weight of 10,000 to 16,000 is used. By setting the viscosity average molecular weight to 16,000 or less, a resin composition having an excellent balance between fluidity and impact resistance can be obtained. The viscosity average molecular weight is preferably less than 15,500, more preferably less than 15,000, particularly less than 14,500, and even more preferably more than 10,500.
The viscosity average molecular weight can be adjusted to such a range by a known method such as controlling the amount of the molecular weight adjusting agent.
As the polycarbonate resin (A), one type or a mixture of two or more types may be used, or two or more types of polycarbonate resins having different viscosity average molecular weights may be mixed to adjust the viscosity average molecular weight. Further, a polycarbonate resin having a viscosity average molecular weight outside the above range may be mixed and used after adjusting to the viscosity average molecular weight.

Here, the viscosity average molecular weight [Mv] of the aromatic polycarbonate resin (A) is the ultimate viscosity [η] (unit: dl / g) at a temperature of 20 ° C. using a Ubbelohde viscometer using methylene chloride as a solvent. Obtained, the viscosity formula of Schnell, that is,
It means a value calculated from η = 1.23 × 10 ^-4 Mv ^0.83.
The ultimate viscosity [η] is a value calculated by the following formula by measuring the specific viscosity [ηsp] at each solution concentration [C] (g / dl).

The terminal hydroxyl group concentration of the aromatic polycarbonate resin (A) is arbitrary and may be appropriately selected and determined, but is usually 1000 ppm or less, preferably 800 ppm or less, and more preferably 600 ppm or less. Thereby, the retention heat stability and the color tone of the polycarbonate resin composition of the present invention can be further improved. Further, the lower limit thereof is usually 10 ppm or more, preferably 30 ppm or more, more preferably 40 ppm or more, particularly in the aromatic polycarbonate resin produced by the melt transesterification method. Thereby, the decrease in the molecular weight can be suppressed, and the mechanical properties of the polycarbonate resin composition of the present invention can be further improved.
The unit of the terminal hydroxyl group concentration is the mass of the terminal hydroxyl group expressed in ppm with respect to the mass of the aromatic polycarbonate resin. The measuring method is carried out by colorimetric quantification by the titanium tetrachloride / acetic acid method (the method described in Macromol. Chem. 88 215 (1965)).

The aromatic polycarbonate resin (A) is not limited to an embodiment containing only one aromatic polycarbonate resin, and two or more aromatic polycarbonate resins having different monomer compositions, molecular weights, terminal hydroxyl group concentrations, etc. are mixed. You may use it.

Further, for example, for the purpose of further improving flame retardancy and impact resistance, an aromatic polycarbonate resin is used as a copolymer with an oligomer or polymer having a siloxane structure; for the purpose of further improving thermal oxidation stability and flame retardancy. Copolymer with monomer, oligomer or polymer having phosphorus atom; Copolymer with monomer, oligomer or polymer having dihydroxyanthraquinone structure for the purpose of improving thermal oxidation stability; Polystyrene to improve optical properties Such as a copolymer with an oligomer or a polymer having an olefin-based structure; a copolymer with a polyester resin oligomer or a polymer for the purpose of improving chemical resistance; etc.; You may.

Further, in order to improve the appearance and fluidity of the molded product, the polycarbonate resin may contain a polycarbonate oligomer. The viscosity average molecular weight [Mv] of this polycarbonate oligomer is usually 1,500 or more, preferably 2,000 or more, and usually 9,500 or less, preferably 9,000 or less. Further, the contained polycarbonate ligomer is preferably 30% by mass or less of the polycarbonate resin (including the polycarbonate oligomer).

Further, the aromatic polycarbonate resin may be not only a virgin raw material but also an aromatic polycarbonate resin recycled from a used product (so-called material recycled aromatic polycarbonate resin). Examples of the used products include optical recording media such as optical disks; light guide plates; automobile window glass, automobile headlamp lenses, vehicle transparent members such as windshields; containers such as water bottles; glasses lenses; soundproof walls, etc. Examples include building members such as glass windows and corrugated sheets. In addition, non-conforming products, crushed products obtained from sprue, runners, etc., or pellets obtained by melting them can also be used.
However, the regenerated aromatic polycarbonate resin is preferably 80% by mass or less, more preferably 50% by mass or less, of the aromatic polycarbonate resin contained in the polycarbonate resin composition of the present invention. .. Since the regenerated aromatic polycarbonate resin is likely to be deteriorated by heat deterioration, aging deterioration, etc., when such an aromatic polycarbonate resin is used in a larger amount than the above range, the hue and mechanical properties are high. This is because it may reduce.

[Silicone compound (B)]
Silicone compounds employed in the present invention (B) is a terminal does not contain silanol groups, is less than the kinematic viscosity at 25 ℃ 3000mm ² / sec ultra 50,000 ^mm 2 / sec, at 25 ° C. The refractive index (nD) is 1.560 to 1.600, and the following formula (1) is satisfied.
| NPC-nSi | × νSi ≤ 21 ... (1)
[In the formula, nPC is the refractive index (nD) of the polycarbonate resin (A), nSi is the refractive index (nD) of the silicone compound (B), and νSi is the kinematic viscosity (25 ° C.) of the silicone compound (B). ]

The silicone compound (B) does not contain a silanol group at the terminal. Usually, silicone resins or silicone oils have silanol-type ends and silanol-type ends that are sealed with a trimethylsiloxy group or the like. However, the silicone compound (B) in the present invention has silanol at the latter end. It is a terminal blockade type that does not contain a group.

（式中、Ｒ^１〜Ｒ^４は、それぞれ独立して、アルキル基、シクロアルキル基、アリール基、アリールアルキル基であり、繰返し単位の数ｎは１以上である。） The silicone compound (B) is preferably a compound represented by the following general formula (1).

(In the formula, R ^{1 to} R ⁴ are independently an alkyl group, a cycloalkyl group, an aryl group, and an arylalkyl group, and the number n of repeating units is 1 or more.)

In the general formula (1), as the alkyl group, an alkyl group having 1 to 10 carbon atoms is preferable, and a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, an n-hexyl group, an octyl group and the like are preferably mentioned. , Especially the methyl group is preferable. As the cycloalkyl group, a cycloalkyl group having 4 to 20 carbon atoms such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group and a methylcyclohexyl group is preferable. As the aryl group, an aryl group having 6 to 20 carbon atoms is preferable, and a phenyl group, a naphthyl group, and particularly a phenyl group are preferable. As the arylalkyl group, an arylalkyl group having 7 to 21 carbon atoms, for example, a benzyl group or a phenylethyl group is preferable.

As the silicone compound (B), in the above general formula (1), ^{polyorganosiloxane in which R 1} is a methyl group and a phenyl group and R ² , R ³ and R ⁴ are a methyl group or a phenyl group is particularly preferable. ..

Silicone compound (B) used in the present invention is, to those skilled in the though called silicone oil, is in the range kinematic viscosity is less than 3000 mm ² / sec ultra 50,000 ^mm 2 / sec at 25 ° C. Among the Use things. When the kinematic viscosity is 3000 mm ² / sec or less, the deposits tend to increase due to the increase in low molecular weight components, and ^{when the kinematic viscosity is 50,000 mm 2} / sec or more, the handleability at the time of compounding and the compatibility with polycarbonate decrease. Transparency is reduced. The kinematic viscosity is preferably 4500 mm ² / sec or more, and preferably 20,000 mm ² / sec or less.

Further, the silicone compound (B) has a refractive index (nD) at 25 ° C. of 1.560 to 1.600. If the refractive index (nD) is less than 1.560 or more than 1.600, the compatibility with polycarbonate is lowered and the transparency is lowered. The refractive index (nD) is preferably 1.570 or more, preferably 1.590 or less.
In the present invention, the refractive index nD of the silicone compound (B) is a value measured using an Abbe refractometer and a wavelength of the D line (589 nm) at a temperature of 25 ° C. The same applies to the refractive index nD of the polycarbonate resin (A) described later.

The present invention is characterized in that the refractive index (nD) and kinematic viscosity (25 ° C.) of the silicone compound (B) satisfy the following formula (1).
| NPC-nSi | × νSi ≤ 21 ... (1)
[In the formula, nPC is the refractive index (nD) of the polycarbonate resin (A), nSi is the refractive index (nD) of the silicone compound (B), and νSi is the kinematic viscosity (25 ° C.) of the silicone compound (B). ]
The above formula (1) shows that when the difference between the refractive index of the polycarbonate resin (A) and the refractive index of the silicone compound (B) is large, the kinematic viscosity of the silicone compound (B) is reduced, and conversely, the polycarbonate resin (B) When the difference in refractive index between A) and the silicone compound (B) is small, it means that it is preferable to adjust the kinematic viscosity of the silicone compound (B) to be large.

The content of the silicone compound (B) is more than 1 part by mass and 7 parts by mass or less with respect to 100 parts by mass of the aromatic polycarbonate resin (A). If the content of the silicone compound (B) is 1 part by mass or less, the flow modification effect is insufficient, and if it exceeds 7 parts by mass, the impact resistance and heat resistance are lowered. The preferable content of the silicone compound (B) is 1.2 parts by mass or more, more preferably 1.5 parts by mass or more, preferably 6 parts by mass or less, and more preferably 5.5 parts by mass or less. ..

[Phosphorus stabilizer]
The polycarbonate resin composition for an optical member of the present invention preferably contains a phosphorus-based stabilizer. By containing a phosphorus-based stabilizer, the hue of the polycarbonate resin composition of the present invention becomes better, and the heat-resistant discoloration property is further improved.
Any known phosphorus-based stabilizer can be used. Specific examples include phosphoric acid, phosphonic acid, phosphite, phosphinic acid, polyphosphoric acid and other phosphorus oxo acids; acidic sodium pyrophosphate, potassium pyrophosphate, acidic calcium pyrophosphate and other acidic pyrophosphate metal salts; phosphoric acid. Phosphates of Group 1 or Group 2B metals such as potassium, sodium phosphate, cesium phosphate, zinc phosphate; phosphate compounds, phosphite compounds, phosphonite compounds and the like can be mentioned, with phosphite compounds being particularly preferred. By selecting the phosphite compound, a polycarbonate resin composition having higher discoloration resistance and continuous productivity can be obtained.

Here, the phosphite compound is a _{trivalent phosphorus compound represented by the general formula: P (OR) 3} , and R represents a monovalent or divalent organic group.
Examples of such phosphite compounds include triphenyl phosphite, tris (monononylphenyl) phosphite, tris (monononyl / dinonyl-phenyl) phosphite, and tris (2,4-di-tert-butylphenyl) phos. Fight, monooctyldiphenylphosphite, dioctylmonophenylphosphite, monodecyldiphenylphosphite, didecylmonophenylphosphite, tridecylphosphite, trilaurylphosphite, tristearylphosphite, distearylpentaerythritol diphosphite, Bis (2,4-di-tert-butyl-4-methylphenyl) pentaerythritol phosphite, bis (2,6-di-tert-butylphenyl) octylphosphite, 2,2-methylenebis (4,6-di) -Tert-Butylphenyl) octylphosphite, tetrakis (2,4-di-tert-butylphenyl) -4,4'-biphenylene-diphosphite, 6- [3- (3-tert-butyl-hydroxy-5-methyl) Phenyl) propoxy] -2,4,8,10-tetra-tert-butyldibenzo [d, f] [1,3,2] -dioxaphosfepine and the like.

Among such phosphite compounds, the aromatic phosphite compound represented by the following formula (2) or (3) is more preferable because the heat-resistant discoloration property of the polycarbonate resin composition of the present invention is effectively enhanced. ..

［式（２）中、Ｒ^１、Ｒ^２及びＲ^３は、それぞれ同一であっても異なっていてもよく、炭素数６以上３０以下のアリール基を表す。］

[In the formula (2), R ¹ , R ² and R ³ may be the same or different, respectively, and represent an aryl group having 6 or more and 30 or less carbon atoms. ]

［式（３）中、Ｒ^４及びＲ^５は、それぞれ同一であっても異なっていてもよく、炭素数６以上３０以下のアリール基を表す。］

[In the formula (3), R ⁴ and R ⁵ may be the same or different, respectively, and represent an aryl group having 6 or more and 30 or less carbon atoms. ]

As the phosphite compound represented by the above formula (2), triphenylphosphine, tris (monononylphenyl) phosphite, tris (2,4-di-tert-butylphenyl) phosphite and the like are preferable. Of these, tris (2,4-di-tert-butylphenyl) phosphite is more preferable. Specific examples of such organic phosphite compounds include "ADEKA STAB 1178" manufactured by ADEKA, "Sumilyzer TNP" manufactured by Sumitomo Chemical Co., Ltd., "JP-351" manufactured by Johoku Chemical Industry Co., Ltd., and "ADEKA STAB" manufactured by ADEKA. 2112 ”,“ Irgaphos 168 ”manufactured by BASF,“ JP-650 ”manufactured by Johoku Chemical Industry Co., Ltd., and the like.

Examples of the phosphite compound represented by the above formula (3) include bis (2,4-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite and bis (2,6-di-tert-). Those having a pentaerythritol diphosphite structure such as butyl-4-methylphenyl) pentaerythritol diphosphite and bis (2,4-dicumylphenyl) pentaerythritol diphosphite are particularly preferable. Specific preferred examples of such an organic phosphite compound include "ADEKA STAB PEP-36" and "ADEKA STAB PEP-24G" manufactured by ADEKA, and "Doverphos S-9228" manufactured by Doverchemical.

Among the phosphite compounds, the aromatic phosphite compound represented by the above formula (3) is more preferable because it has a more excellent hue.
The phosphorus-based stabilizer may contain one type or two or more types in any combination and ratio.

The content of the phosphorus-based stabilizer is preferably 0.005 to 0.5 parts by mass, more preferably 0.007 parts by mass or more, still more preferably 0, with respect to 100 parts by mass of the aromatic polycarbonate resin (A). .008 parts by mass or more, particularly preferably 0.01 parts by mass or more, more preferably 0.4 parts by mass or less, further preferably 0.3 parts by mass or less, particularly preferably 0.2 parts by mass or less, 0 Most preferably, it is 1 part by mass or less. When the content of the phosphorus-based stabilizer is less than 0.005 parts by mass in the above range, the hue and heat-resistant discoloration are likely to be insufficient, and when the content of the phosphorus-based stabilizer exceeds 0.5 parts by mass, the hue and heat-resistant discoloration are likely to be insufficient. The heat-resistant discoloration tends to deteriorate, and the wet-heat stability also tends to decrease.

[Additives, etc.]
The polycarbonate resin composition for an optical member of the present invention includes other additives other than those described above, such as antioxidants, mold release agents, ultraviolet absorbers, fluorescent whitening agents, pigments, dyes, and other than polycarbonate resins. It can contain additives such as polymers, flame retardants, impact improvers, antistatic agents, plasticizers and compatibilizers. These additives may be used alone or in combination of two or more.

[Manufacturing method of polycarbonate resin composition]
The method for producing the polycarbonate resin composition of the present invention is not limited, and a known method for producing the polycarbonate resin composition can be widely adopted, and the aromatic polycarbonate resin (A) and the silicone compound (B), and if necessary, blended. After mixing the other components to be made in advance using various mixers such as a tumbler and a Henschel mixer, a mixer such as a Banbury mixer, a roll, a brabender, a single-screw kneading extruder, a twin-screw kneading extruder, or a kneader is used. Examples thereof include a method of melt-kneading. The temperature of melt-kneading is not particularly limited, but is usually in the range of 240 to 320 ° C.

[Optical member]
The polycarbonate resin composition for an optical member of the present invention can produce an optical member by molding pellets obtained by pelletizing the above-mentioned polycarbonate resin composition by various molding methods. Further, the resin melt-kneaded by the extruder can be directly molded into an optical member without passing through pellets.

Since the polycarbonate resin composition of the present invention has excellent transparency and an excellent balance between fluidity and impact resistance, it is suitably used for molding an optical member, particularly a thin-walled optical member, particularly by an injection molding method. ..

Here, the thin wall refers to a molded product (member) having a plate-shaped portion having a normal wall thickness of 3 mm or less, preferably 2 mm or less, preferably 1 mm or less, and more preferably 0.8 mm or less. The plate-shaped portion may be a flat plate or a curved plate, may have a flat surface, may have irregularities on the surface, and has an inclined cross section. Alternatively, it may have a wedge-shaped cross section or the like.

Examples of the optical member include parts of devices and appliances that directly or indirectly use a light source such as an LED, an organic EL, an incandescent lamp, a fluorescent lamp, and a cathode tube, and a light guide plate, a member for a surface light emitter, and the like are typical. Illustrated as a thing.
The light guide plate is for guiding the light of a light source such as an LED in a liquid crystal backlight unit, various display devices, and a lighting device, and the light input from the side surface or the back surface is usually provided on the front surface. It diffuses due to the unevenness and emits uniform light. Its shape is usually flat and may or may not have irregularities on its surface.
Molding of the light guide plate is usually preferably performed by an injection molding method, an ultra-high speed injection molding method, an injection compression molding method or the like.

The light guide plate using the polycarbonate resin composition of the present invention can be suitably used in the fields of liquid crystal backlight units, various display devices, and lighting devices. Examples of such devices include various mobile terminals such as mobile phones, mobile notebooks, netbooks, slate PCs, tablet PCs, smartphones, tablet terminals, cameras, watches, notebook computers, various displays, lighting devices, and the like. Be done.

Further, as the optical member, a light guide, a lens, or the like that guides light from a light source such as an LED in a headlamp (head lamp) for a vehicle such as an automobile or a motorcycle, a rear lamp, a fog lamp, or the like is also suitable. Can also be suitably used.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the present invention is not construed as being limited to the following examples.
The raw materials and evaluation methods used in the following examples and comparative examples are as follows.

(Examples 1 to 3 and Comparative Examples 1 to 10)
[Manufacturing of resin composition pellets]
Each of the above components is blended in the proportions (parts by mass) shown in Table 2 and below, mixed in a tumbler for 20 minutes, and then a single-screw extruder with a vent with a screw diameter of 40 mm (“VS” manufactured by Tanabe Plastic Machinery Co., Ltd.). −40 ”), melt-kneading was performed at a cylinder temperature of 250 ° C., and pellets were obtained by strand cutting.

[Transparency evaluation]
After the pellets obtained above are dried at 110 ° C. for 5 hours, a cylinder is used using an injection molding machine (“SE8M” manufactured by Sumitomo Heavy Industries, Ltd.) and a drop mold as shown in FIG. Under the conditions of temperature of 340 ° C, injection speed of 10 mm / sec, molding cycle of 10 seconds, and mold temperature of 40 ° C, the state of the molded product after 100 shot injection molding is visually evaluated and judged according to the following criteria. did.
◯: It is transparent.
X: It is opaque and / or there is occurrence of silver streaks.

The drop mold of FIG. 2 is a mold designed so that the resin composition is introduced from the gate G and the generated gas easily accumulates in the tip P portion. The width of the gate G is 1 mm and the thickness is 1 mm. In FIG. 2, the width h1 is 14.5 mm, the length h2 is 7 mm, the length h3 is 27 mm, and the thickness of the molded portion is 3 mm.

[Liquidity evaluation (Q value)]
After the obtained pellets are dried at 110 ° C. for 5 hours or more, the unit time of the composition is set at 240 ° C. and a load of 160 kgf by the method described in JIS K7210 Annex C using an enhanced flow tester. The outflow amount Q value per unit (unit: × ^10-2 cm ³ / sec) was measured, and the fluidity was evaluated. The orifice used had a diameter of 1 mm and a length of 10 mm. The higher the Q value, the better the fluidity.

[Impact resistance evaluation (Charpy impact strength)]
The obtained pellets are dried at 110 ° C. for 5 hours, and then in an injection molding machine (“NEX80III” manufactured by Nissei Resin Industry Co., Ltd.) under the conditions of a cylinder temperature of 250 ° C., a mold temperature of 80 ° C., and a molding cycle of 45 seconds. , ISO179-1, 2 to prepare a 3 mm thick impact resistance test piece. The obtained test piece was notched with R1 mm / depth of 2 mm, and the measurement was performed by measuring the notched Charpy impact strength (kJ / m ² ) in a temperature environment of 23 ° C.

[Heat resistance evaluation (Tg)]
As an evaluation of heat resistance, Tg (glass transition temperature, unit: ° C.) is measured by using a differential scanning calorimeter (“DSC220” manufactured by SII Nanotechnology Co., Ltd.) according to JIS K7121 to obtain pellets of each resin composition. The DSC curve was measured by heating 7 mg at a heating rate of 20 ° C./min. Next, in accordance with JIS K7121 (1987), a straight line extending the baseline on the low temperature side to the high temperature side and a tangent line drawn at a point where the slope of the curve at the stepwise change part of the glass transition is maximized. The outer glass transition start temperature, which is the temperature at the intersection of, was obtained and used as the glass transition temperature. The larger the value of Tg, the better the heat resistance.
The above evaluation results are shown in Tables 2 and 3 below.

FIG. 1 is a graph in which fluidity (horizontal axis: Q value) and impact strength (vertical axis: Charpy impact value) are plotted among the evaluation results of Examples and Comparative Examples. From the graph of FIG. 1, the example (● and solid line) is shifted to the upper right as compared with the comparative example (▲ and broken line), and both fluidity and impact resistance are remarkably improved. I understand.

The polycarbonate resin composition of the present invention has an excellent balance between fluidity and impact strength, and can be extremely suitably used for various optical members, particularly a thin-walled light guide plate, and therefore has very high industrial applicability.

Claims (3)

A resin composition containing more than 1 part by mass and 7 parts by mass or less of the silicone compound (B) with respect to 100 parts by mass of the aromatic polycarbonate resin (A) having a viscosity average molecular weight of 12,000 to 16,000.
The silicone compound (B) does not contain a silanol group at the terminal, has a kinematic viscosity at 25 ° C of ^{more than 3000 mm 2} / sec to 9200 mm ² / sec or less , and has a refractive index (nD) of 1 at 25 ° C. A polycarbonate resin composition for an optical member, which is .560 to 1.600 and satisfies the following formula (1).
| NPC-nSi | × νSi ≤ 21 ... (1)
[In the formula, nPC is the refractive index (nD) of the polycarbonate resin (A), nSi is the refractive index (nD) of the silicone compound (B), and νSi is the kinematic viscosity (25 ° C.) of the silicone compound (B). ] An optical member made of the polycarbonate resin composition according to claim 1. The optical member according to claim 2, wherein the optical member is a light guide plate.

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