JP5283275B2 - Optical lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical lens made of a polycarbonate resin, which has excellent transparency and color tone stability and exhibits excellent optical characteristics by low birefringence. <P>SOLUTION: The optical lens is obtained by molding a polycarbonate resin composition (E) comprising 100 pts.wt. of a resin component comprising 97-99.95 wt.% of a polycarbonate resin (A) and 0.05-3 wt.% of a polystyrene resin (B) having a weight average molecular weight of 1,000-18,000, and 0.02-2 pts.wt. of a phosphoric antioxidant (C) and/or a phenolic antioxidant (D). The optical lens has total light transmittance of &ge;89.0% and the reduction rate of birefringence of the optical lens calculated by expression: reduction rate (%) of birefringence=(&sigma;PC-&sigma;)&times;100/&sigma;PC is &ge;5%, wherein &sigma; represents a birefringence measured by using a test piece of 1 mm thickness obtained from the polycarbonate resin composition (E); and &sigma;PC represents a birefringence measured by using a test piece of 1 mm thickness obtained from the same polycarbonate resin (A) as that used as a constituent of the polycarbonate resin composition (E). Since the optical lens is excellent in transparency, mechanical properties, heat resistance and hue stability, even in molding of the lens, a hue change and degradation of the resin itself are avoided, and the optical lens of very high industrial utility value is acquired. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an optical lens made of polycarbonate resin. More specifically, by using a polystyrene resin and a phosphorus-based antioxidant and / or a phenol-based antioxidant, it is made of a polycarbonate resin having excellent transparency and color tone stability and excellent optical properties due to low birefringence. The present invention relates to an optical lens.

  Polycarbonate resins are excellent in transparency and impact resistance, and are expected to be used as optical lens materials. Optical lenses made of polycarbonate resin are safer than conventional glass lenses and acrylic plastic lenses, and are safer because of their high impact resistance even when they are lighter and lighter. It has been used as a material for various lenses such as a lens for a barcode reader, a lens for a camera of a mobile phone, and a pickup lens.

  The conventional optical lens made of polycarbonate resin has a problem that the birefringence is large and optical anisotropy occurs. This is because, when injection molding or the like is performed in a molten state of a polycarbonate resin, the orientation of polymer molecules occurs, the refractive index for linearly polarized light polarized in the orientation direction, and the refractive index for linearly polarized light polarized in the direction orthogonal to the orientation direction This is because the birefringence occurs inside the obtained optical lens molded article. (This phenomenon is called orientation birefringence.) When light is transmitted through an optical lens having a large orientation birefringence, the speed of two light beams having different vibration directions are different from each other. There has been a problem that the imaging performance is greatly reduced, and a solution has been demanded.

In order to solve this problem, Patent Document 1 proposes a method using a modified methyl methacrylate resin having low birefringence. However, since the modified methyl methacrylate resin has low heat resistance and impact strength, there is a problem that the range of use is limited as an optical lens molded product.
On the other hand, Patent Document 2 proposes an aromatic polycarbonate copolymer obtained by using a bisphenol compound having a specific structure in order to reduce the intrinsic birefringence of the polycarbonate resin itself, that is, the photoelastic coefficient. . However, the copolymer is intended to improve the birefringence of the optical disk substrate, and teaches nothing about being useful in optical lenses and having excellent transparency and color stability. It has not been.

Japanese Patent Laid-Open No. 10-300901 JP-A-2-99521

  An object of the present invention is to provide an optical lens made of polycarbonate resin which is excellent in transparency and color tone stability, and further exhibits excellent optical characteristics due to low birefringence.

  As a result of intensive studies to solve the above problems, the present inventor has achieved transparency and color stability by adding a specific polystyrene resin and a phosphorus-based antioxidant or a phenol-based antioxidant to the polycarbonate resin. It has been found that an optical lens made of polycarbonate resin exhibiting excellent and low birefringence can be obtained.

That is, the present invention relates to 100 parts by weight of a resin component comprising 97 to 99.95% by weight of a polycarbonate resin (A) and 0.05 to 3% by weight of a polystyrene resin (B) having a weight average molecular weight of 1000 to 18000, and a phosphorus system. An optical lens formed by molding a polycarbonate resin composition (E) comprising 0.02 to 2 parts by weight of an antioxidant (C) and / or a phenolic antioxidant (D),
The total light transmittance of the optical lens is 89.0% or more, and the birefringence reduction rate calculated by the following formula is 5% or more.
The present invention relates to an optical lens.
Reduction rate of birefringence (%) = (σPC−σ) × 100 / σPC
(here,
σ is a test piece having a thickness of 1 mm obtained from the polycarbonate resin composition (E).
The birefringence measured using
σPC is used as a constituent of the polycarbonate resin composition (E).
1mm thickness obtained from the same polycarbonate resin (A)
The birefringence measured using the test piece of
Represent each. )

  Since the optical lens of the present invention is excellent in transparency, mechanical properties, heat resistance and hue stability, the hue does not change or the resin itself does not deteriorate even in the molding process of the lens. Industrial value is extremely high.

  The polycarbonate resin (A) used in the present invention is obtained by a phosgene method in which various dihydroxy diaryl compounds and phosgene are reacted or a transesterification method obtained by reacting a dihydroxy diaryl compound and a carbonate such as diphenyl carbonate. A typical example is a polycarbonate resin produced from 2,2-bis (4-hydroxyphenyl) propane (bisphenol A).

  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.

  These are used individually or in mixture of 2 or more types. In addition to these, piperazine, dipiperidyl hydroquinone, resorcin, 4,4'-dihydroxydiphenyl, and the like may be mixed and used.

Furthermore, the above dihydroxyaryl compound and a trivalent or higher phenol compound as shown below may be used in combination.
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.

  The viscosity average molecular weight of the polycarbonate resin (A) is usually 10,000 to 100,000, preferably 12,000 to 30,000, more preferably 15,000 to 24,000. In producing such a polycarbonate resin, a molecular weight regulator, a catalyst and the like can be used as necessary.

The above viscosity average molecular weight is 0.5 wt% polycarbonate resin solution using methylene chloride as a solvent, and the specific viscosity (η _sp ) is measured at a temperature of 20 ° C. using a Cannon-Fenske type viscosity tube. [Η] was obtained and calculated from the following SCHNELL equation.
[Η] = 1.23 × 10 ⁻⁴ M ^0.83

  The weight average molecular weight of the polystyrene resin (B) used in the present invention is 1000 to 18000. If the weight average molecular weight of the polystyrene resin (B) is out of this range, the total light transmittance is inferior, and a decrease in birefringence cannot be expected. More preferably, it is 1500-10000, More preferably, it is the range of 2000-4000.

  The composition ratio of the polystyrene resin (B) is 0.05 to 3% by weight based on the resin component consisting of (A) and (B). If the composition ratio of the polystyrene resin (B) is out of this range, the total light transmittance is inferior, and a decrease in birefringence cannot be expected. A more preferable range is 0.1 to 1% by weight.

  Commercially available polystyrene resin (B) includes JONCRYL ADF-1300 manufactured by BASF.

Examples of the phosphorus-based antioxidant (C) and / or the phenol-based antioxidant (D) used in the present invention include the following compounds.
As phosphorus antioxidant (C), what consists of 1 type or more among the compounds represented by the following general formula 1, 2, and 3 is mentioned.
General formula 1

（一般式１において、Ｒ１〜４は炭素数１〜２０のアルキル基、またはアルキル基で
置換されてもよいアリール基を示す。）
一般式２

(In General Formula 1, R1-4 represent an alkyl group having 1 to 20 carbon atoms or an aryl group which may be substituted with an alkyl group.)
General formula 2

（一般式２において、Ｒ５、Ｒ６は炭素数１〜２０のアルキル基、またはアルキル基で置換されてもよいアリール基を、ａ、ｂは整数０〜３を示す。）
一般式３

(In General Formula 2, R5 and R6 represent an alkyl group having 1 to 20 carbon atoms or an aryl group which may be substituted with an alkyl group, and a and b represent integers 0 to 3.)
General formula 3

（一般式３において、Ｒ７は炭素数１〜２０のアルキル基、またはアルキル基で置換されてもよいアリール基を、ｃは０〜３の整数を示す。）

(In General Formula 3, R7 represents an alkyl group having 1 to 20 carbon atoms or an aryl group which may be substituted with an alkyl group, and c represents an integer of 0 to 3)

  The compound of general formula 1 is Sandstub P-EPQ manufactured by Clariant Japan, the compound of general formula 2 is Adekastab PEP-36 manufactured by Adeka, and the compound of general formula 3 is Sumitizer P- manufactured by Sumitomo Chemical. 168 is listed as commercially available.

  Moreover, as a phenolic antioxidant (D), the compound of the following general formula 4 is mentioned. Formula 4

（一般式４において、Ｒ８は炭素数１〜２０のアルキル基、またはアルキル基で置換されてもよいアリール基を示す。）

(In General Formula 4, R8 represents an alkyl group having 1 to 20 carbon atoms or an aryl group which may be substituted with an alkyl group.)

As the compound of the general formula 4, Irganox 1076 manufactured by Ciba Specialty Chemicals is commercially available.

  The compounding quantity of phosphorus antioxidant (C) and / or phenolic antioxidant (D) is 0.02-2 weight part per 100 weight part of resin components which consist of (A) and (B). If the blending amount is less than 0.02 parts by weight, the thermal stability is poor, which is not preferable. On the other hand, if it exceeds 2 parts by weight, the total light transmittance is lowered, which is not preferable. A more preferable amount is 0.04 to 1 part by weight, and more preferably 0.05 to 0.2 part by weight. In this range, the total light transmittance does not decrease, and excellent thermal stability is exhibited.

  In addition, various heat stabilizers, antioxidants, colorants, mold release agents, softeners, antistatic agents, and other additives, impact modifiers, and other polymers are added as long as the effects of the present invention are not impaired. You may mix | blend.

  There are no particular limitations on the method of mixing the various components of the polycarbonate resin composition used in the optical lens of the present invention, and examples include mixing with a known mixer such as a tumbler or ribbon blender, or melt kneading with an extruder. It is done.

  There is no restriction | limiting in particular in the method of shape | molding the polycarbonate resin composition used for the optical lens of this invention, A well-known injection molding method, compression molding method, extrusion molding method, etc. can be used.

  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.

(Preparation of polycarbonate resin composition pellets)
Based on the ingredients and amounts shown in Tables 1 to 4, various ingredients are mixed using a tumbler and melt kneaded at a cylinder temperature of 220 ° C. using a 40 mm diameter single screw extruder (manufactured by Tanabe Plastics). Various pellets were obtained.
The compounding components used are as follows.
1. Polycarbonate resin:
Polycarbonate resin synthesized from bisphenol A and carbonyl chloride Caliber 301-6 (viscosity average molecular weight: 24000) manufactured by Sumitomo Dow
(Hereinafter abbreviated as “PC”)

2. Polystyrene resin:
JONCRYL ADF-1300 made by BASF
(Weight average molecular weight: 2800, hereinafter abbreviated as “PS1”)
Polystyrene (weight average molecular weight: 800) manufactured by Aldrich
(Hereafter abbreviated as “PS2”.)
Polystyrene (weight average molecular weight: 4000) manufactured by Aldrich
(Hereinafter abbreviated as “PS3”)
Polystyrene (weight average molecular weight: 20000) manufactured by Aldrich
(Hereinafter abbreviated as “PS4”)

3. Phosphorous antioxidants:
P-EPQ made by Clariant Japan
(Hereinafter abbreviated as “P-based AO1”)
Adeka Corporation Adeka Stub PEP-36
(Hereinafter abbreviated as “P-based AO2”.)
P-168 manufactured by Sumitomo Chemical Co., Ltd.
(Hereinafter abbreviated as “P-based AO3”)
4). Phenolic antioxidants:
Irganox 1076 manufactured by Ciba Specialty Chemicals
(Hereinafter abbreviated as “Ph-based AO”)

(Chromaticity, total light transmittance and birefringence measurement specimen creation method)
After drying the various pellets obtained at 120 ° C. for 4 hours, a test piece for measuring chromaticity and transmittance at 280 ° C. and an injection pressure of 1200 kg / cm 2 using an injection molding machine (J-100SAII manufactured by Nippon Steel) 90 × 50 × 2 mm). For birefringence measurement, a test piece of 90 × 50 × 1 mm was used.

(Chromaticity evaluation method)
The chromaticity was measured using a spectrophotometer CMS35-SP manufactured by Murakami Color Research Laboratory with a D65 light source and a viewing angle of 10 °. When the chromaticity measurement was performed at n = 10, the difference between the maximum value and the minimum value of x and y was 0.0005 or less. The results are shown in Tables 1 to 3.

(Evaluation method of total light transmittance)
The total light transmittance was measured using a Haze Meter HM-150 manufactured by Murakami Color Research Laboratory. A total light transmittance Tt of 89.0% or more was regarded as acceptable. The results are shown in Tables 1 to 3.

(Evaluation method of birefringence)
Birefringence was measured using a polarization strain meter (polarimeter) of Shinko Seiki.
Birefringence is defined as follows:
Birefringence σn [−]
= Phase difference (nm) / Sample thickness (nm) = (θ × 589/180) / t
θ: Rotation analyzer rotation angle Equivalent extinction angle of linearly polarized light (unit: °)
589: wavelength of monochromatic light used (yellow light of Na discharge lamp) (unit: nm)
180: rotation analyzer half-rotation angle (unit: °)
The birefringence reduction rate was calculated based on the following formula, and 5% or more was deemed acceptable.
Reduction rate of birefringence (%) = (σPC−σ) × 100 / σPC
(here,
σ is a test piece having a thickness of 1 mm obtained from the polycarbonate resin composition (E).
The birefringence measured using
σPC is used as a constituent of the polycarbonate resin composition (E).
1mm thickness obtained from the same polycarbonate resin (A)
The birefringence measured using the test piece of
Represent each. )
The results are shown in Tables 1 to 3.

判定： 合格（○）、不合格（×）

Judgment: Pass (○), Fail (×)

判定： 合格（○）、不合格（×）

Judgment: Pass (○), Fail (×)

判定： 合格（○）、不合格（×）

Judgment: Pass (○), Fail (×)

  As shown in Examples 1 to 10, the polycarbonate resin composition having the requirements of the present invention exhibited high total light transmittance and luminance, excellent hue stability and low haze value.

Comparative Example 1 was a case where the blending amount of PS1 was less than the specified amount, and the total light transmittance and the birefringence reduction rate were inferior.
Comparative Example 2 was a case where the blending amount of PS1 was larger than the specified amount, and the total light transmittance was inferior.
Comparative Example 3 was a case where the blending amount of the phosphorus antioxidant was less than specified, and the hue stability was inferior.
In Comparative Example 4, the total amount of light transmittance was inferior when the amount of the phosphorus-based antioxidant was greater than the specified amount.
In Comparative Example 5, PS2 having a weight average molecular weight of 800 was used, and the total light transmittance was inferior.
In Comparative Example 6, when PS4 having a weight average molecular weight of 20000 was used, the total light transmittance and the birefringence reduction rate were inferior.

Claims (7)

Polycarbonate resin (A) 97 to 99.95% by weight and polystyrene resin (B) having a weight average molecular weight of 1000 to 18000, 100 parts by weight of resin component consisting of 0.05 to 3% by weight and phosphorus antioxidant (C) And / or an optical lens formed by molding a polycarbonate resin composition (E) comprising 0.02 to 2 parts by weight of a phenolic antioxidant (D),
The total light transmittance of the optical lens is 89.0% or more, and the birefringence reduction rate calculated by the following formula is 5% or more.
An optical lens characterized by the above.
Reduction rate of birefringence (%) = (σPC−σ) × 100 / σPC
(here,
σ is a test piece having a thickness of 1 mm obtained from the polycarbonate resin composition (E).
The birefringence measured using
σPC is used as a constituent of the polycarbonate resin composition (E).
1mm thickness obtained from the same polycarbonate resin (A)
The birefringence measured using the test piece of
Represent each. )   2. The optical lens according to claim 1, wherein the polystyrene resin (B) has a weight average molecular weight of 1500 to 10,000.   The optical lens according to claim 1, wherein the polystyrene resin (B) has a weight average molecular weight of 2000 to 4000.   4. The optical lens according to claim 1, wherein the composition ratio of the polystyrene resin (B) is 0.1 to 2% by weight based on the resin component.   The amount of the phosphorus-based antioxidant (C) and / or the phenol-based antioxidant (D) is 0.05 to 0.2 parts by weight per 100 parts by weight of the resin component. The optical lens according to 1. The optical lens according to claim 1, wherein the phosphorus-based antioxidant (C) is one or more compounds selected from the compounds represented by the following general formulas 1, 2, and 3.
General formula 1

(In General Formula 1, R1-4 represent an alkyl group having 1 to 20 carbon atoms or an aryl group which may be substituted with an alkyl group.)
General formula 2

(In General Formula 2, R5 and R6 represent an alkyl group having 1 to 20 carbon atoms or an aryl group which may be substituted with an alkyl group, and a and b represent integers 0 to 3.)
General formula 3

(In General Formula 3, R7 represents an alkyl group having 1 to 20 carbon atoms or an aryl group which may be substituted with an alkyl group, and c represents an integer of 0 to 3) The optical lens according to claim 1, wherein the phenolic antioxidant (D) is a compound represented by the following general formula 4.
Formula 4

(In General Formula 4, R8 represents an alkyl group having 1 to 20 carbon atoms or an aryl group which may be substituted with an alkyl group.)