WO2012096410A1

WO2012096410A1 - Optical lens comprising aromatic-aliphatic polycarbonate resin

Info

Publication number: WO2012096410A1
Application number: PCT/JP2012/051009
Authority: WO
Inventors: 輝幸重松; 学松井; 丹藤　和志; 和徳布目
Original assignee: 帝人化成株式会社
Priority date: 2011-01-14
Filing date: 2012-01-12
Publication date: 2012-07-19
Also published as: CN103339531B; TWI515223B; JPWO2012096410A1; CN103339531A; TW201245275A; KR20140006810A; KR101881616B1; JP5688101B2

Abstract

The purpose of the present invention is to provide an optical lens which comprises an aromatic-aliphatic polycarbonate resin that has a large Abbe number and combines practically sufficient heat resistance with high molding flowability. This optical lens comprises a polycarbonate resin characterized in that the polycarbonate resin comprises constituent units (I) represented by formula (I) and constituent units (II) represented by formula (II), the proportion of the constituent units (II) to the sum of the constituent units (I) and (II) being 55-35 mol%, and that a solution obtained by dissolving 0.7 g of the polycarbonate resin in 100 mL of methylene chloride has a specific viscosity measured at 20ºC of 0.12-0.298.

Description

Optical lens made of aromatic-aliphatic polycarbonate resin

The present invention relates to an optical lens made of an aromatic-aliphatic polycarbonate resin having a high Abbe number and having both practically sufficient heat resistance and high molding fluidity.

Optical glass or optical transparent resin is used as a material for optical elements used in optical systems of various cameras such as cameras, film-integrated cameras, and video cameras. Optical glass is excellent in heat resistance, transparency, dimensional stability, chemical resistance, etc., and there are many types of materials with various refractive indexes and Abbe numbers, but the material cost is high and moldability is high. However, there is a problem that productivity is low.
On the other hand, optical lenses made of transparent optical resins, especially thermoplastic transparent resins, have the advantage that they can be mass-produced by injection molding, and are currently used for many lenses, including camera lenses. ing. Among them, polycarbonate resin obtained from 2,2-bis (4-hydroxyphenyl) propane (commonly known as bisphenol A) has excellent properties such as transparency and heat resistance, and mechanical properties such as impact resistance. Many are used in optical lenses.
However, the polycarbonate resin made of bisphenol A has a disadvantage that the refractive index and the Abbe number are poor because the refractive index is as high as 1.585 but the Abbe number is as low as 30, so that the problem of chromatic aberration tends to occur. In addition, the resin used for the optical lens also requires molding fluidity in order to reduce optical distortion generated during injection molding or to mold a thin object.
In order to solve such drawbacks of the polycarbonate resin, several copolymer polycarbonate resins of bisphenol and aliphatic diol have been proposed.
In Patent Document 1, a polycarbonate composed of cyclohexanedimethanol and aromatic bisphenol is studied. When the ratio of cyclohexanedimethanol is high, the Abbe number is high, but the heat resistance is low. Conversely, when the ratio of cyclohexanedimethanol is low, the heat resistance is high, but the Abbe number is low. As for aromatic bisphenols, bisphenol A and 1,1-bis (4-hydroxyphenyl) cyclohexane give high Abbe numbers, but tend to be inferior in heat resistance, and 9,9-bis (4-hydroxy -3-Methylphenyl) fluorene imparts heat resistance but reduces the Abbe number.
In addition to the above heat resistance and Abbe number characteristics, the optical lens is also required to have moldability when molded into an optical lens.
For the reasons described above, there is still room for improvement in providing an optical lens made of a resin that does not lack high Abbe number, heat resistance, and moldability.
JP 2003-90901 A

An object of the present invention is to provide an optical lens made of an aromatic-aliphatic polycarbonate resin having a high Abbe number and having both practically sufficient heat resistance and high molding fluidity.
The present inventor has found that when an aromatic-aliphatic polycarbonate resin having a specific molecular structure is used, an optical lens excellent in Abbe number and heat resistance can be obtained. Further, the present inventors have found that the polycarbonate resin is excellent in molding fluidity and can precisely mold a fine optical lens, thereby completing the present invention.
That is, the object of the present invention is achieved by the following invention.
1. Formula (I)

A structural unit (I) represented by the formula (II)

And the proportion of the structural unit (II) is 55 to 35 mol% with respect to the total of the structural units (I) and (II),
0.7 g of the polycarbonate resin is dissolved in 100 ml of methylene chloride, and the specific viscosity measured at 20 ° C. is 0.12 to 0.298.
An optical lens made of a polycarbonate resin.
2. 2. The optical lens according to item 1, wherein the content of the compound represented by the following formula (III) in the polycarbonate resin is 50 to 300 ppm / g.

3. 2. The optical lens according to item 1, wherein the polycarbonate resin has a glass transition point of 115 to 160 ° C. and an Abbe number of 43 to 35.
4). 2. The optical lens according to item ¹ , wherein the polycarbonate resin has a photoelastic coefficient of 50 × 10 ⁻¹² Pa ⁻¹ to 30 × 10 ⁻¹² Pa ⁻¹ .
5. 2. The optical lens according to item 1, wherein the polycarbonate resin has a refractive index of 1.53 to 1.55.
6). 2. The optical lens according to item 1, which is a diffractive lens.
7. The diffractive lens has a thickness of 0.05 to 3.0 mm, a ring-shaped diffraction grating depth of 5 to 20 μm, a lens portion effective radius of 1.0 to 20.0 mm, a ring zone number of 5 to 30 and a minimum ring zone pitch of 5 to 20 μm 7. The optical lens according to item 6, which is an aspherical diffractive lens having a concave curvature radius of 0.1 to 10.0 mm and a diameter of 1.0 to 30.0 mm.

FIG. 1 is a proton NMR chart of Example 2 (cyclohexanedimethanol in polycarbonate resin (hereinafter sometimes referred to as “CHDM”. CHDM is a compound represented by the following formula (IV). ) Component and 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane (hereinafter sometimes referred to as “Bis-TMC”. Bis-TMC is represented by the above formula (III). The component ratio is 50:50).
FIG. 2 is an enlarged view of the proton NMR chart (FIG. 1) of Example 2.

The polycarbonate resin is composed of a structural unit (I) that is a 1,4-cyclohexanedimethanol residue and a structural unit (II that is a 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane residue. )including.
The proportion of the structural unit (II) is 55 to 35 mol% with respect to the total of the structural units (I) and (II). When the proportion of the structural unit (II) is lower than 35 mol%, the entanglement effect of molecular chains by 3,3,5-trimethylcyclohexane, which is a side chain, decreases, and the heat resistance of the resin decreases. As a result, a molded product satisfying heat resistance may not be obtained. When the proportion of the structural unit (II) is higher than 55% by mole, the 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane having an aromatic ring has an influence on the aromatic ring and is in the resin. The polarizability of increases. Accordingly, the Abbe number decreases. The proportion of the structural unit (II) is preferably 50 to 40 mol% with respect to the total of the structural units (I) and (II).
The polycarbonate resin substantially consists of the structural units (I) and (II). As long as the object of the present invention is not impaired, a known copolymer component other than (I) and (II) may be included. From such a viewpoint, it is preferable that 90 mol% or more of the structural units of the entire polycarbonate resin are the structural units (I) and (II), and further 95 mol% or more are the structural units (I) and (II). It is more preferable.
The polycarbonate resin has 0.70 g dissolved in 100 cc of methylene chloride, and the specific viscosity measured at 20 ° C. is in the range of 0.12 to 0.298. The specific viscosity is preferably in the range of 0.15 to 0.295, more preferably 0.20 to 0.29. When the specific viscosity is less than 0.12, the molded product becomes brittle, and when it is higher than 0.298, the melt viscosity and the solution viscosity become high and handling becomes difficult.
In the polycarbonate resin, the content of 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane represented by the following formula (III) is preferably 50 to 300 ppm / g, more preferably 70. It is ˜250 ppm / g, more preferably 100 to 200 ppm / g.

The content of the compound represented by the formula (III) can be adjusted by increasing the vacuum, that is, the reaction time at 1 Torr or less. When the reaction is not performed at a vacuum level of 1 Torr or less, the content of the compound represented by the formula (III) increases. Moreover, when reaction time is too long, it will distill too much from in resin.
More specifically, in order to bring the content of the compound represented by the formula (III) within this range, the reaction time under the condition of 240 ° C. or higher and 1 Torr or lower, which is the final condition of the polymerization reaction, is 0 minute. It is necessary to make it 1 hour or less.
When the content of the compound represented by the formula (III) is within the above range, molding fluidity can be improved without impairing the Abbe number and heat resistance of the polycarbonate resin. However, if it is 300 ppm or more, the mold contamination becomes severe at the time of injection molding, which is not preferable, and if it is 50 ppm or less, the molding fluidity is inferior.
The glass transition temperature (Tg) of the polycarbonate resin measured at a heating rate of 20 ° C./min is preferably 115 to 160 ° C., more preferably 120 to 155 ° C. If the Tg is less than 115 ° C, the heat resistance of the optical lens formed using the copolymer is not sufficient. On the other hand, if the Tg exceeds 160 ° C, the melt viscosity becomes high, and handling for forming a molded body is difficult. Is not preferable because it becomes difficult.
The Abbe number of the polycarbonate resin at 25 ° C. is preferably in the range of 43 to 35, more preferably 43 to 38. If it is smaller than 35, the chromatic aberration increases, which is not preferable for an optical lens.
The refractive index of the polycarbonate resin at 25 ° C. and a wavelength of 589 nm is preferably 1.53 to 1.55, more preferably 1.540 to 1.545. If it is smaller than 1.53, the lens needs a thickness, which is not preferable.
The photoelastic coefficient of the polycarbonate resin is preferably 50 × 10 ^-12 Pa ^-1 ~ 30 × 10 ^-12 Pa ^-1 , More preferably 45 × 10 ^-12 Pa ^-1 ~ 30 × 10 ^-12 Pa ^-1 It is. Photoelasticity is 50 × 10 ^-12 Pa ^-1 If it is larger, birefringence occurs in the molded product, which is not preferable.
(Manufacture of polycarbonate resin)
As a method for producing the polycarbonate resin, a method used for producing a normal polycarbonate resin is arbitrarily adopted. For example, a reaction between diol and phosgene or a transesterification reaction between diol and carbonate is preferably employed.
In the reaction of diol and phosgene, the reaction is performed in the presence of an acid binder and a solvent in a non-aqueous system. Examples of the acid binder include pyridine, dimethylaminopyridine, tertiary amine and the like. As the solvent, for example, halogenated hydrocarbons such as methylene chloride and chlorobenzene are used. It is desirable to use a terminal terminator such as phenol or p-tert-butylphenol as the molecular weight regulator. The reaction temperature is usually 0 to 40 ° C., and the reaction time is preferably several minutes to 5 hours.
In the transesterification reaction, the diol is stirred in the presence of an inert gas, and the reaction is usually performed at 120 to 350 ° C., preferably 150 to 300 ° C. under reduced pressure. The degree of vacuum is changed stepwise, and finally the alcohols produced at 1 mmHg or less are distilled out of the system. The reaction time is usually about 1 to 4 hours. In the transesterification reaction, a polymerization catalyst can be used to promote the reaction. As such a polymerization catalyst, an alkali metal compound, an alkaline earth metal compound or a heavy metal compound may be used as a main component, and a nitrogen-containing basic compound may be used as a subsidiary component if necessary.
Examples of the alkali metal compound include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium bicarbonate, potassium bicarbonate, lithium bicarbonate, sodium carbonate, potassium carbonate, lithium carbonate, sodium acetate, potassium acetate, lithium acetate, sodium stearate. , Potassium stearate, lithium stearate, sodium salt of bisphenol A, potassium salt, lithium salt, sodium benzoate, potassium benzoate, lithium benzoate and the like. Alkaline earth metal compounds include calcium hydroxide, barium hydroxide, magnesium hydroxide, strontium hydroxide, calcium bicarbonate, barium bicarbonate, magnesium bicarbonate, strontium bicarbonate, calcium carbonate, barium carbonate, magnesium carbonate, strontium carbonate , Calcium acetate, barium acetate, magnesium acetate, strontium acetate, calcium stearate, barium stearate, magnesium stearate, strontium stearate and the like, among which sodium hydroxide and sodium bicarbonate are preferred.
Examples of the nitrogen-containing basic compound include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, trimethylbenzylammonium hydroxide, trimethylamine, triethylamine, dimethylbenzylamine, triphenylamine, dimethylaminopyridine and the like. Of these, tetramethylammonium hydroxide is preferred.
Other transesterification catalysts include zinc, tin, zirconium, lead, titanium, germanium, antimony, osmium, and aluminum salts. For example, zinc acetate, zinc benzoate, zinc 2-ethylhexanoate, tin (II) chloride, tin (IV) chloride, tin (II) acetate, tin (IV) acetate, dibutyltin dilaurate, dibutyltin oxide, dibutyltin dimethoxide, Zirconium acetylacetonate, zirconium oxyacetate, zirconium tetrabutoxide, lead (II) acetate, lead (IV) titanium tetrabutoxide (IV) and the like are used.
These catalysts may be used alone or in combination of two or more. The amount of these polymerization catalysts used is 10 with respect to 1 mol of the diol in total. ^-9 ~ 10 ^-3 Used in molar ratios. These may be used alone or in combination of two or more. In the transesterification reaction, a diaryl carbonate having an electron-withdrawing substituent may be added at a later stage or after completion of the polycondensation reaction in order to reduce the hydroxy end group. Furthermore, an antioxidant or a heat stabilizer may be added to improve the hue.
In the polycarbonate resin, the catalyst may be removed or deactivated after the polymerization reaction in order to maintain thermal stability and hydrolysis stability. For alkali metal compounds or alkaline earth metal compounds, generally, a method of deactivating a catalyst by adding a known acidic substance is preferably carried out.
Specific examples of these substances include esters such as butyl benzoate, aromatic sulfonic acids such as p-toluenesulfonic acid, and aromatic sulfonic acids such as butyl p-toluenesulfonate and hexyl p-toluenesulfonate. Esters, phosphoric acids such as phosphorous acid, phosphoric acid, phosphonic acid, triphenyl phosphite, monophenyl phosphite, diphenyl phosphite, diethyl phosphite, di-n-propyl phosphite, phosphorous acid Phosphorous esters such as di-n-butyl, di-n-hexyl phosphite, dioctyl phosphite, monooctyl phosphite, triphenyl phosphate, diphenyl phosphate, monophenyl phosphate, dibutyl phosphate, phosphorus Phosphate esters such as dioctyl acid and monooctyl phosphate, phosphones such as diphenylphosphonic acid, dioctylphosphonic acid and dibutylphosphonic acid , Phosphonic acid esters such as diethyl phenylphosphonate, phosphines such as triphenylphosphine and bis (diphenylphosphino) ethane, boric acids such as boric acid and phenylboric acid, and aromatics such as tetrabutylphosphonium dodecylbenzenesulfonate Organic halides such as aromatic sulfonates, stearic acid chloride, benzoyl chloride, p-toluenesulfonic acid chloride, alkyl sulfuric acids such as dimethyl sulfate, and organic halides such as benzyl chloride are preferably used. Of these, tetrabutylphosphonium salt of dodecylbenzenesulfonate is preferable. These deactivators are used in an amount of 0.01 to 50 times mol, preferably 0.3 to 20 times mol for the amount of catalyst. When the amount is less than 0.01 times the amount of the catalyst, the deactivation effect is insufficient, which is not preferable. Moreover, when it is more than 50 times mole with respect to the amount of catalyst, since heat resistance falls and it becomes easy to color a molded object, it is unpreferable.
(Optical lens)
The optical lens of the present invention is molded by an arbitrary method such as an injection molding method, a compression molding method, an injection compression molding method, or a casting method.
When manufacturing by injection molding, it is preferable to mold under conditions of a cylinder temperature of 230 to 300 ° C and a mold temperature of 90 to 150 ° C. More preferably, molding is performed under conditions of a cylinder temperature of 240 to 280 ° C. and a mold temperature of 100 to 140 ° C. When the cylinder temperature exceeds 300 ° C., the resin is decomposed and colored, and when it is less than 230 ° C., the melt viscosity is high and cannot be molded. When the mold temperature exceeds 150 ° C., the resin is not cured and the molded piece cannot be taken out from the mold. Furthermore, if it is less than 90 ° C., the resin quickly hardens in the mold during molding, and a molded piece cannot be obtained, or the mold molding cannot be transferred.
The optical lens of the present invention is preferably an aspheric lens. Since an aspheric lens can substantially eliminate spherical aberration with a single lens, there is no need to remove spherical aberration with a combination of a plurality of spherical lenses, thus reducing weight and reducing production costs. It becomes possible. Therefore, the aspherical lens is particularly useful as a camera lens among optical lenses.
In the present invention, the polycarbonate resin is particularly useful as a material for an optical lens having a thin, small and complicated shape because of its high molding fluidity. As a specific lens size, the thickness of the central portion is 0.05 to 3.0 mm, more preferably 0.05 to 2.0 mm, and still more preferably 0.1 to 2.0 mm. The diameter is 1.0 mm to 30.0 mm, more preferably 1.0 to 20.0 mm, and still more preferably 3.0 to 10.0 mm. In addition, it is preferably a meniscus lens having a convex surface on one side and a concave surface on the other side.
Furthermore, the aspherical lens of the present invention includes a diffractive lens, a Fresnel lens, an fθ lens, a cylinder lens, a collimator lens and the like in addition to the meniscus lens. Especially, since the moldability of the polycarbonate resin is good, it is suitable for a diffractive lens that requires transferability.
The diffractive lens of the present invention is molded by any method such as mold forming, cutting, polishing, laser processing, electric discharge processing, and edging. Furthermore, mold molding is more preferable.
In the diffractive lens of the present invention, a sawtooth diffraction grating is formed concentrically on the surface of the lens substrate. Further, an optical adjustment layer may be formed as a protective film so as to cover the diffraction grating. The shape of the optical adjustment layer opposite to the surface in contact with the lens substrate is formed so as to be substantially the same as the envelope surface passing through the grooves of the diffraction grating.
In the diffractive lens of the present invention, the optical adjustment layer is formed so as to have substantially the same shape as the envelope surface passing through the grooves of the diffraction grating, whereby the light condensing property is improved and the MTF characteristic is improved.
Note that the envelope surface passing through the grooves of the diffraction grating can take a spherical shape, an aspherical shape, a cylindrical shape, or the like. In particular, a configuration in which the envelope surface is designed to be aspherical is preferable because it is possible to correct lens aberration that could not be corrected in the case of a spherical shape. The “aspherical surface” is a curved surface that satisfies the following formula.

The above expression represents an aspherical surface when rotated about the Z axis perpendicular to the XY plane, where c is the central curvature, and A, B, C, and D are deviations from the quadric surface. It is a coefficient to represent. Further, depending on the value of K, the following aspheric surface is obtained.
When 0> K, an ellipsoid whose minor axis is the optical axis
When -1 <K <0, the ellipsoid whose major axis is the optical axis
When K = -1, paraboloid
When K <-1, hyperboloid
In the diffractive lens of the present invention, the diffraction grating and the optical adjustment layer may be formed on one side or both sides of the lens. When formed on both sides, the diffraction gratings on both sides do not necessarily have the same depth and shape. Also, the annular zone pitch in the diffraction grating need not be the same. Further, the shape of the lens may be a convex surface on which at least one surface is formed with a diffraction grating shape and an optical adjustment layer, and may be a concave surface, a convex surface, a biconvex surface, or the like in addition to a flat surface and a convex surface. Further, it is desirable to set the depth of the diffraction grating to 20 μm or less in order to ensure the ease of mold processing, the contribution of the diffraction grating shape in terms of lens performance, and the stability to the ambient temperature. For a diffraction grating shape having a depth exceeding several tens of μm, it is difficult to mold with high processing accuracy. This is because die machining is generally performed using a cutting tool, but if the depth of the diffraction grating is deep, the amount of processing increases and the tip of the cutting tool wears, so that the processing accuracy deteriorates. At the same time, when the depth of the diffraction grating is increased, the pitch of the diffraction grating cannot be reduced. This is because when the diffraction grating becomes deep, it is necessary to process the die with a tool having a large curvature radius at the tip, and as a result, the diffraction grating cannot be processed unless the pitch of the diffraction grating is widened to some extent. As a result, as the depth of the diffraction grating increases, the degree of freedom in designing the diffraction grating shape disappears, and the aberration reduction effect by the diffraction grating almost disappears.
The aspherical diffractive lens has a thickness of 0.05 to 3.0 mm, a ring-shaped diffraction grating depth of 5 to 20 μm, a lens portion effective radius of 1.0 to 20.0 mm, a ring number of 5 to 25, and a minimum ring zone pitch of 5. It is preferably an aspherical diffractive lens having a diameter of 0.0 to 20.0 μm, a concave curvature radius of 0.1 to 10.0 mm, and a diameter of 1.0 to 30.0 mm.
The thickness of the aspherical diffractive lens is more preferably 0.1 to 2.0 mm. More preferably, the depth of the annular diffraction grating is 10 to 20 μm. More preferably, the effective radius of the lens portion is 2 to 15.0 mm. More preferably, the number of ring zones is 10 to 20. More preferably, the minimum annular zone pitch is 8.0 to 15.0 μm. More preferably, the concave curvature radius is 0.1 to 5.0 mm. More preferably, the diameter is 2.0 to 20.0 mm.
The optical adjustment layer of the diffractive lens of the present invention is preferably a resin having a lower refractive index wavelength dispersion than the lens, that is, a resin having an Abbe number larger than that of the lens. Furthermore, it is preferable that the optical adjustment layer is easy to manufacture and is easy to handle and stable after formation. Further, from the viewpoint of optical selection range and ease of manufacture, it is preferable to use a resin that can be cured on a lens diffraction grating and then cured to obtain a stable optical adjustment layer. Furthermore, in order to reduce the influence on the lens when forming the optical adjustment layer, it is preferable to use a photocurable resin such as an ultraviolet curable resin that can be produced with low energy and has a short production time. From such a viewpoint, the optical adjustment layer is preferably an ultraviolet curable acrylic resin or epoxy resin.
Various additives can be used for the optical lens of the present invention in order to impart various characteristics within a range not impairing the object of the present invention. Additives include mold release agents, heat stabilizers, UV absorbers, bluing agents, antistatic agents, flame retardants, heat ray shielding agents, fluorescent dyes (including fluorescent whitening agents), pigments, light diffusing agents, and reinforcing fillers. Other resins and elastomers can be blended.
As a mold release agent, that whose 90 weight% or more consists of ester of alcohol and a fatty acid is preferable. Specific examples of the ester of alcohol and fatty acid include monohydric alcohol and fatty acid ester and / or partial ester or total ester of polyhydric alcohol and fatty acid. The monohydric alcohol and fatty acid ester is preferably an ester of a monohydric alcohol having 1 to 20 carbon atoms and a saturated fatty acid having 10 to 30 carbon atoms. The partial ester or total ester of a polyhydric alcohol and a fatty acid is preferably a partial ester or total ester of a polyhydric alcohol having 1 to 25 carbon atoms and a saturated fatty acid having 10 to 30 carbon atoms.
Specific examples of the monohydric alcohol, saturated fatty acid and ester include stearyl stearate, palmityl palmitate, butyl stearate, methyl laurate, isopropyl palmitate and the like, and stearyl stearate is preferable.
Specific examples of partial esters or total esters of polyhydric alcohols and saturated fatty acids include stearic acid monoglyceride, stearic acid diglyceride, stearic acid triglyceride, stearic acid monosorbate, behenic acid monoglyceride, pentaerythritol monostearate, pentaerythritol tetra Full or partial esters of dipentaerythritol such as stearate, pentaerythritol tetrapelargonate, propylene glycol monostearate, biphenyl biphenate, sorbitan monostearate, 2-ethylhexyl stearate, dipentaerythritol hexastearate, etc. Is mentioned. Among these esters, stearic acid monoglyceride, stearic acid triglyceride, pentaerythritol tetrastearate, and a mixture of stearic acid triglyceride and stearyl stearate are preferably used.
The amount of the ester in the release agent is preferably 90% by weight or more, and more preferably 95% by weight or more when the release agent is 100% by weight.
The content of the release agent in the polycarbonate resin granules is preferably in the range of 0.005 to 2.0 parts by weight with respect to 100 parts by weight of the polycarbonate resin granules, and 0.01 to 0.6 parts by weight. Is more preferable, and a range of 0.02 to 0.5 parts by weight is even more preferable.
Examples of the heat stabilizer include a phosphorus heat stabilizer, a sulfur heat stabilizer, and a hindered phenol heat stabilizer.
Examples of the phosphorous heat stabilizer include phosphorous acid, phosphoric acid, phosphonous acid, phosphonic acid and esters thereof. Specifically, triphenyl phosphite, tris (nonylphenyl) phosphite, tris ( 2,4-di-tert-butylphenyl) phosphite, tris (2,6-di-tert-butylphenyl) phosphite, tridecyl phosphite, trioctyl phosphite, trioctadecyl phosphite, didecyl monophenyl phosphite Phyto, dioctyl monophenyl phosphite, diisopropyl monophenyl phosphite, monobutyl diphenyl phosphite, monodecyl diphenyl phosphite, monooctyl diphenyl phosphite, bis (2,6-di-tert-butyl-4-methylphenyl) penta Erisrito Diphosphite, 2,2-methylenebis (4,6-di-tert-butylphenyl) octyl phosphite, bis (nonylphenyl) pentaerythritol diphosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol di Phosphite, distearyl pentaerythritol diphosphite, tributyl phosphate, triethyl phosphate, trimethyl phosphate, triphenyl phosphate, diphenyl monoorthoxenyl phosphate, dibutyl phosphate, dioctyl phosphate, diisopropyl phosphate, dimethyl benzenephosphonate, diethyl benzenephosphonate, Dipropyl benzenephosphonate, tetrakis (2,4-di-t-butylphenyl) -4,4'-biphenylenediphosphonite Tetrakis (2,4-di-t-butylphenyl) -4,3′-biphenylenediphosphonite, tetrakis (2,4-di-t-butylphenyl) -3,3′-biphenylenediphosphonite, bis ( 2,4-di-tert-butylphenyl) -4-phenyl-phenylphosphonite, bis (2,4-di-tert-butylphenyl) -3-phenyl-phenylphosphonite, and (6- (3- ( 3-t-butyl-4-hydroxy-5-methyl) propoxy) -2,4,8,10-tetra-t-butyldibenz (d, f) (1,3,2) -dioxaphosphipine Can be mentioned.
Among them, tris (2,4-di-tert-butylphenyl) phosphite, tris (2,6-di-tert-butylphenyl) phosphite, tetrakis (2,4-di-tert-butylphenyl) -4 , 4′-biphenylenediphosphonite, tetrakis (2,4-di-t-butylphenyl) -4,3′-biphenylenediphosphonite, tetrakis (2,4-di-t-butylphenyl) -3,3 '-Biphenylenediphosphonite, bis (2,4-di-tert-butylphenyl) -4-phenyl-phenylphosphonite and bis (2,4-di-tert-butylphenyl) -3-phenyl-phenylphosphonite , (6- (3- (3-t-butyl-4-hydroxy-5-methyl) propoxy) -2,4,8,10-tetra-t-butyldibenz (d f) (1,3,2) - di oxa phosphinothricin pins are used
Particularly preferred is tetrakis (2,4-di-tert-butylphenyl) -4,4′-biphenylenediphosphonite, (6- (3- (3-t-butyl-4-hydroxy-5-methyl) propoxy) -2,4,8,10-tetra-t-butyldibenz (d, f) (1,3,2) -dioxaphosphipine is used, and the phosphorus compound is Sumitomo Chemical Co., Ltd. Since -16, it is marketed as Sumilizer GP (trade name), etc., and can be easily used.
The content of the phosphorous heat stabilizer in the polycarbonate resin particles is preferably 0.001 to 0.2 parts by weight with respect to 100 parts by weight of the polycarbonate resin particles.
As the sulfur-based heat stabilizer, pentaerythritol-tetrakis (3-laurylthiopropionate), pentaerythritol-tetrakis (3-myristylthiopropionate), pentaerythritol-tetrakis (3-stearylthiopropionate), Examples include dilauryl-3, 3′-thiodipropionate, dimyristyl-3, 3′-thiodipropionate, distearyl-3, 3′-thiodipropionate. Among them, pentaerythritol-tetrakis (3-laurylthiopropionate), pentaerythritol-tetrakis (3-myristylthiopropionate), dilauryl-3, 3′-thiodipropionate, dimyristyl-3, 3′-thio Dipropionate is preferred. Particularly preferred is pentaerythritol-tetrakis (3-laurylthiopropionate). The thioether compounds are commercially available from Sumitomo Chemical Co., Ltd. as Sumilizer TP-D (trade name), Sumilizer TPM (trade name), and the like, and can be easily used.
The content of the sulfur-based heat stabilizer in the polycarbonate resin particles is preferably 0.001 to 0.2 parts by weight with respect to 100 parts by weight of the polycarbonate resin particles.
Examples of the hindered phenol heat stabilizer include triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3 , 5-di-tert-butyl-4-hydroxyphenyl) propionate], pentaerythritol-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3 5-di-tert-butyl-4-hydroxyphenyl) propionate, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, N, N-hexamethylene bis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamide) 3,5-di-tert-butyl-4-hydroxy-benzylphosphonate-diethyl ester, tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate and 3,9-bis {1,1- And dimethyl-2- [β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl} -2,4,8,10-tetraoxaspiro (5,5) undecane. . Octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate is particularly preferably used.
The content of the hindered phenol heat stabilizer in the polycarbonate resin granules is preferably 0.001 to 0.3 parts by weight with respect to 100 parts by weight of the polycarbonate resin granules.
As the UV absorber, at least one UV absorber selected from the group consisting of benzotriazole UV absorbers, benzophenone UV absorbers, triazine UV absorbers, cyclic imino ester UV absorbers, and cyanoacrylates Is preferred.
Examples of the benzotriazole ultraviolet absorber include 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-5-tert-octylphenyl) benzotriazole, 2- (2-hydroxy-3, 5-Dicumylphenyl) phenylbenzotriazole, 2- (2-hydroxy-3-tert-butyl-5-methylphenyl) -5-chlorobenzotriazole, 2,2′-methylenebis [4- (1,1,3 , 3-tetramethylbutyl) -6- (2N-benzotriazol-2-yl) phenol], 2- (2-hydroxy-3,5-di-tert-butylphenyl) benzotriazole, 2- (2-hydroxy -3,5-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2-hydroxy- 3,5-di-tert-amylphenyl) benzotriazole, 2- (2-hydroxy-5-tert-octylphenyl) benzotriazole, 2- (2-hydroxy-5-tert-butylphenyl) benzotriazole, 2- (2-hydroxy-4-octoxyphenyl) benzotriazole, 2,2′-methylenebis (4-cumyl-6-benzotriazolephenyl), 2,2′-p-phenylenebis (1,3-benzoxazine-4 -One), 2- [2-hydroxy-3- (3,4,5,6-tetrahydrophthalimidomethyl) -5-methylphenyl] benzotriazole. These can be used alone or in a mixture of two or more. Preferably, 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-5-tert-octylphenyl) benzotriazole, 2- (2-hydroxy-3,5-dicumylphenyl) Phenylbenzotriazole, 2- (2-hydroxy-3-tert-butyl-5-methylphenyl) -5-chlorobenzotriazole, 2,2′-methylenebis [4- (1,1,3,3-tetramethylbutyl) ) -6- (2N-benzotriazol-2-yl) phenol], 2- [2-hydroxy-3- (3,4,5,6-tetrahydrophthalimidomethyl) -5-methylphenyl] benzotriazole. . More preferably, 2- (2-hydroxy-5-tert-octylphenyl) benzotriazole, 2,2′-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2N-benzo Triazol-2-yl) phenol].
Examples of benzophenone-based ultraviolet absorbers include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-benzyloxybenzophenone, 2-hydroxy-4- Methoxy-5-sulfoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfoxytrihydridolate benzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2 ', 4,4'-tetrahydroxybenzophenone 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxy-5-sodiumsulfoxybenzophenone, bis (5-benzoyl-4-hydroxy-2- Methoxyphenyl) methane, 2-hy Examples include droxy-4-n-dodecyloxybenzophenone and 2-hydroxy-4-methoxy-2′-carboxybenzophenone.
Examples of the triazine ultraviolet absorber include 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) oxy] -phenol, 2- (4,6-bis ( And 2.4-dimethylphenyl) -1,3,5-triazin-2-yl) -5-[(octyl) oxy] -phenol.
Examples of cyclic imino ester UV absorbers include 2,2′-bis (3,1-benzoxazin-4-one) and 2,2′-p-phenylenebis (3,1-benzoxazin-4-one). 2,2′-m-phenylenebis (3,1-benzoxazin-4-one), 2,2 ′-(4,4′-diphenylene) bis (3,1-benzoxazin-4-one), 2,2 ′-(2,6-naphthalene) bis (3,1-benzoxazin-4-one), 2,2 ′-(1,5-naphthalene) bis (3,1-benzoxazin-4-one) ), 2,2 ′-(2-methyl-p-phenylene) bis (3,1-benzoxazin-4-one), 2,2 ′-(2-nitro-p-phenylene) bis (3,1- Benzoxazin-4-one) and 2,2 ′-(2-chloro-p-phenylene) bis (3,1-benzoxazin-4-one) and the like are exemplified. Among them, 2,2′-p-phenylenebis (3,1-benzoxazin-4-one), 2,2 ′-(4,4′-diphenylene) bis (3,1-benzoxazin-4-one) And 2,2 ′-(2,6-naphthalene) bis (3,1-benzoxazin-4-one) are preferred, especially 2,2′-p-phenylenebis (3,1-benzoxazine-4 -On) is preferred. Such a compound is commercially available from Takemoto Yushi Co., Ltd. as CEi-P (trade name) and can be easily used.
As the cyanoacrylate ultraviolet absorber, 1,3-bis-[(2′-cyano-3 ′, 3′-diphenylacryloyl) oxy] -2,2-bis [(2-cyano-3,3-diphenyl) Examples include acryloyl) oxy] methyl) propane and 1,3-bis-[(2-cyano-3,3-diphenylacryloyl) oxy] benzene.
The blending amount of the ultraviolet absorber is preferably 0.01 to 3.0 parts by weight, more preferably 0.02 to 1.0 parts by weight, even more preferably 100 parts by weight of the polycarbonate resin granules. Is 0.05 to 0.8 part by weight. If it is the range of this compounding quantity, it is possible to provide sufficient weather resistance to a polycarbonate resin molded product according to a use.
Examples of the bluing agent include Macrolex Violet B and Macrolex Blue RR manufactured by Bayer and polysynthremble-RLS manufactured by Clariant. The bluing agent is effective for eliminating the yellow color of the polycarbonate resin particles. In particular, in the case of polycarbonate resin granules with weather resistance, a certain amount of UV absorber is blended, so there is a reality that the polycarbonate resin molded product tends to be yellowish due to the "action and color of the UV absorber". In particular, the blending of a bluing agent is very effective for imparting a natural transparency to a sheet or lens.

The following examples further illustrate the present invention.
1. An evaluation sample was prepared by the following method.
(A) Cast film:
5 g of the obtained polycarbonate resin is dissolved in 50 ml of methylene chloride and cast on a glass petri dish. After sufficiently drying at room temperature, it was dried for 8 hours at a temperature of 20 ° C. or less from the Tg of the polycarbonate resin. A cast film was created.
(B) Aspheric lens:
The obtained polycarbonate resin was vacuum-dried at 100 ° C. for 4 hours, then pelletized using a Φ30 mm twin screw extruder with a vent, and heat-dried at 100 ° C. for 8 hours. Thereafter, a lens having a thickness of 0.6 mm, a convex curvature radius of 5 mm, a concave curvature radius of 4 mm, and a Φ5 mm using a SE30DU injection molding machine manufactured by Sumitomo Heavy Industries, Ltd. at a molding temperature of Tg + 110 ° C. and a mold temperature of Tg-10 ° C. Was injection molded.
(C) Aspherical diffractive lens:
Similar to (b) above, the thickness is 0.3 mm, the ring-shaped diffraction grating is 15 μm deep, the lens portion has an effective radius of 0.865 mm, the number of ring zones is 19, the minimum ring zone pitch is 14 μm, the concave curvature radius is 0.1 mm, and Φ6 mm An aspherical diffractive lens was injection molded.
(D) Molded plate In the same manner as (b) above, a molded plate having a width of 2.5 cm, a length of 5 cm, and a thickness of 3 mm was injection molded.
2. Evaluation was based on the following method.
(1) Specific viscosity:
The polycarbonate resin was sufficiently dried, and the specific viscosity (η _sp ) at 20 ° C. of the solution was measured from a solution in which 0.7 g of the polycarbonate resin was dissolved in 100 ml of methylene chloride.
(2) Copolymerization ratio:
The polycarbonate resin was measured using proton NMR of JNM-AL400 manufactured by JEOL.
(3) Glass transition point (Tg):
The polycarbonate resin was measured by DuPont 910 type DSC.
(4) Refractive index ( _nd ), Abbe number (v):
The 3 mm-thick molded plate molded in the above (d) was measured using a Shimadzu Corp. Kalnew precision refractometer KPR-2000.
v = (n _d −1) / (n _f −n _c ) v: Abbe number n _d : refractive index of d line (587.6 nm) n _f : refractive index of F line (486.1 nm) n _c : C Refractive index of line (656.3 nm) (5) Photoelastic coefficient:
The cast film having a thickness of 100 μm formed in the above (a) was measured for phase difference (Re) at 589 nm using an ellipsometer M-220 manufactured by JASCO Corporation, and the photoelastic coefficient was obtained from the inverse sine function. .
(6) Formability:
The aspherical lens molded in the above (b) was visually checked for filling defects, molding defects, lens brittleness, and the like. Evaluation was classified according to the probability of being defective during molding, less than 1% (◎), 1% or more to less than 5% (５), 5% to less than 20% (Δ), or 20% or more (x).
(7) Transferability:
The surface shape of the aspherical diffraction lens molded in the above (c) was measured using a color 3D laser microscope VK-9710 manufactured by KEYENCE. The surface shape is evaluated by the depth of the annular diffraction grating, the number of zones, etc., and the probability of being a defective product is less than 1% (、１), 1% to less than 5% (○) 5% to less than 20% ( Δ), classified by 20% or more (×).
(8) Content of unreacted Bis-TMC The content of Bis-TMC represented by the formula (III) in the resin was eluted with a column of Develosil ODS-7 manufactured by Nomura Chemical, acetonitrile / 0.2% acetic acid. Using a mixed solution of water and acetonitrile, HPLC analysis was performed with a gradient program at a column temperature of 30 ° C. and a detector of 277 nm. The measurement was carried out by dissolving 1.5 g of polycarbonate resin in 15 ml of methylene chloride, adding 135 ml of acetonitrile, stirring, concentrating with an evaporator, filtering with a 0.2 μm filter, and injecting 10 μl of this measurement solution. It was.
Example 1
CHDM 38.91 parts by weight, Bis-TMC 102.36 parts by weight, diphenyl carbonate (hereinafter sometimes abbreviated as “DPC”) 132.39 parts by weight, sodium hydroxide 0.24 mg and tetramethylammonium hydroxide 27.3 mg The mixture was placed in a reaction kettle equipped with a stirrer and a distillation apparatus, heated to 180 ° C. under a nitrogen atmosphere of 760 Torr, and stirred for 20 minutes. Thereafter, the degree of vacuum was adjusted to 13.4 kPa over 20 minutes, the temperature was raised to 200 ° C. at a rate of 60 ° C./hr, and held for 40 minutes. Then, it heated up to 240 degreeC over 60 minutes, and transesterification was performed. Thereafter, the pressure was reduced to 1 Torr or less over 80 minutes, and the polymerization reaction was carried out with stirring for 30 minutes under the conditions of 240 ° C. and 1 Torr or less. After adding 14.06 mg of dodecylbenzenesulfonic acid tetrabutylphosphonium salt as a deactivator and stirring at 240 ° C. and 1.33 × 10 ⁴ Pa for 20 minutes, the produced polycarbonate resin was extracted while pelletizing.
The polycarbonate resin had a molar ratio of CHDM to Bis-TMC of 45:55 and a specific viscosity of 0.281. The content of unreacted Bis-TMC was 120 ppm / g. An evaluation sample was prepared by the methods (a) to (d) described above using the obtained polycarbonate resin.
Example 2
A polyester carbonate copolymer was prepared in the same manner as in Example 1 except that the amount of CHDM used in Example 1 was 43.26 parts by weight, the amount of Bis-TMC used was 93.12 parts by weight, and DPC 132.39 parts by weight. Synthesized.
The polycarbonate resin had a CHDM to Bis-TMC ratio of 50:50 in molar ratio and a specific viscosity of 0.255. The content of unreacted Bis-TMC was 180 ppm / g. An evaluation sample was prepared by the methods (a) to (d) described above using the obtained polycarbonate resin.
Example 3
A polyester carbonate copolymer was prepared in the same manner as in Example 1 except that the amount of CHDM used in Example 1 was 47.59 parts by weight, the amount of Bis-TMC used was 83.08 parts by weight, and DPC 132.39 parts by weight. Synthesized.
The polycarbonate resin had a molar ratio of CHDM to Bis-TMC of 55:55 and a specific viscosity of 0.232. The content of unreacted Bis-TMC was 220 ppm / g. An evaluation sample was prepared by the methods (a) to (d) described above using the obtained polycarbonate resin.
Example 4
A polyester carbonate copolymer was prepared in the same manner as in Example 1 except that the amount of CHDM used in Example 1 was 56.24 parts by weight, the amount of Bis-TMC used was 65.18 parts by weight, and DPC 132.39 parts by weight. Synthesized.
The polycarbonate resin had a molar ratio of CHDM to Bis-TMC of 65:35 and a specific viscosity of 0.298. The content of unreacted Bis-TMC was 80 ppm / g. An evaluation sample was prepared by the methods (a) to (d) described above using the obtained polycarbonate resin.
Comparative Example 1
25.96 parts by weight of CHDM, 130.37 parts by weight of Bis-TMC, 132.39 parts by weight of DPC, 0.24 mg of sodium hydroxide and 27.3 mg of tetramethylammonium hydroxide were placed in a reaction kettle equipped with a stirrer and a distiller, and nitrogen was added. The mixture was heated to 180 ° C. under an atmosphere of 760 Torr and stirred for 20 minutes. Thereafter, the degree of vacuum was adjusted to 13.4 kPa over 20 minutes, the temperature was raised to 200 ° C. at a rate of 60 ° C./hr, and held for 40 minutes. Then, it heated up to 240 degreeC over 60 minutes, and transesterification was performed. Thereafter, the pressure was reduced to 1 Torr or less over 80 minutes, and the polymerization reaction was carried out with stirring for 2 hours under the conditions of 240 ° C. and 1 Torr or less. Then, after adding 14.06 mg of dodecylbenzenesulfonic acid tetrabutylphosphonium salt as a deactivator and stirring at 240 ° C. and 1.33 × 10 ⁴ Pa for 20 minutes, the produced polycarbonate resin was extracted while pelletizing.
The polycarbonate resin had a molar ratio of CHDM to Bis-TMC of 30:70 and a specific viscosity of 0.435. The content of unreacted Bis-TMC was 20 ppm / g. An evaluation sample was prepared by the methods (a) to (d) described above using the obtained polycarbonate resin.
Comparative Example 2
The amount of CHDM used in Comparative Example 1 was 60.57 parts by weight, the amount of Bis-TMC used was 55.87 parts by weight, DPC 132.39 parts by weight, and the polymerization reaction time was not performed under the conditions of 240 ° C. and 1 Torr or less. In the same manner as in Comparative Example 1, a polycarbonate resin was synthesized.
The polycarbonate resin had a molar ratio of CHDM to Bis-TMC of 70:30 and a specific viscosity of 0.100. The content of unreacted Bis-TMC was 550 ppm / g. An evaluation sample was prepared by the methods (a) to (d) described above using the obtained polycarbonate resin.
Comparative Example 3
The same procedure as in Example 1 was performed except that the amount of CHDM used was 43.37 parts by weight, the amount of bisphenol A (hereinafter sometimes referred to as “BPA”) was 68.67 parts by weight, and DPC 132.39 parts by weight. Thus, a polycarbonate resin was synthesized.
The polycarbonate resin had a CHDM to BPA ratio of 50:50 in molar ratio and a specific viscosity of 0.280. An evaluation sample was prepared by the methods (a) to (d) described above using the obtained polycarbonate resin.
Comparative Example 4
The amount of CHDM used was 43.37 parts by weight, the amount of 1,1-bis (4-hydroxyphenyl) cyclohexane (hereinafter sometimes abbreviated as “Bis-Z”) was 80.51 parts by weight, and DPC 132.39. A polycarbonate resin was synthesized in the same manner as in Comparative Example 1 except that the polymerization reaction time under the conditions of parts by weight, 240 ° C. and 1 Torr or less was 1.5 hours.
The polycarbonate resin had a molar ratio of CHDM to Bis-Z of 50:50 and a specific viscosity of 0.374. An evaluation sample was prepared by the methods (a) to (d) described above using the obtained polycarbonate resin.
Comparative Example 5
The amount of CHDM used in Comparative Example 3 was 43.33 parts by weight, the amount of BPA used was 54.88 parts by weight, Bis-TMC was 18.66 parts by weight, and DPC 132.39 parts by weight, at 240 ° C. and 1 Torr or less. A polycarbonate resin was synthesized in the same manner as in Comparative Example 1 except that the reaction time was 4 hours.
The polycarbonate resin had a molar ratio of CHDM, BPA and Bis-TMC of 50:40:10, and a specific viscosity of 0.468. An evaluation sample was prepared by the methods (a) to (d) described above using the obtained polycarbonate resin.
Comparative Example 6
The amount of CHDM used in Comparative Example 3 was 43.33 parts by weight, the amount of BPA used was 54.88 parts by weight, Bis-TMC was 18.66 parts by weight, DPC 132.39 parts by weight, 240 ° C., 1 Torr or less. A polycarbonate resin was synthesized in the same manner as in Example 1 except that the polymerization reaction time was 30 minutes.
The polycarbonate resin had a molar ratio of CHDM, BPA and Bis-TMC of 50:40:10, and a specific viscosity of 0.285. An evaluation sample was prepared by the methods (a) to (d) described above using the obtained polycarbonate resin.
Table 1 shows the results of Examples 1 to 4 and Comparative Examples 1 to 6.
In Examples 1 to 4, Tg is in an appropriate range, a lens can be molded, the Abbe number is high, and it is suitable as an optical lens. On the other hand, Comparative Example 1 has a low Abbe number and, under the above molding conditions, the specific viscosity is high, resulting in poor moldability. When the molding temperature is Tg + 110 ° C. or higher, the resin decomposes and the lens cannot be molded. . In Comparative Example 2, although the Abbe number is high, the Tg is low and the heat resistance is insufficient, and the molded lens is brittle because the specific viscosity is low. Since Comparative Example 3 has a low Tg, the heat resistance is insufficient, and the resin is hard to solidify and cannot be molded under the above molding conditions. Comparative Example 4 has a low Tg and poor heat resistance. Further, under the above molding conditions, the specific viscosity is high and the transferability is poor. Comparative Example 5 has a low Tg, poor heat resistance, and a large photoelastic coefficient. Comparative Example 6 has a low Tg and a large photoelastic coefficient. Further, under the above molding conditions, the mold release is poor and the moldability is poor. For these reasons, Comparative Examples 1 to 6 cannot be used for optical lenses, or the range of use is limited.

Effects of the Invention The optical lens of the present invention has a high Abbe number, and further has both heat resistance sufficient for practical use and high molding fluidity. The optical lens of the present invention can be suitably used in the field of expensive glass lenses.

The optical lens of the present invention has a high Abbe number, and further has practically sufficient heat resistance and high molding fluidity. it can.

Claims

Formula (I)

A structural unit (I) represented by the formula (II)

And the proportion of the structural unit (II) is 55 to 35 mol% with respect to the total of the structural units (I) and (II),
0.7 g of the polycarbonate resin is dissolved in 100 ml of methylene chloride, and the specific viscosity measured at 20 ° C. is 0.12 to 0.298.
An optical lens made of a polycarbonate resin.
2. The optical lens according to claim 1, wherein the content of the compound represented by the following formula (III) in the polycarbonate resin is 50 to 300 ppm / g.
The optical lens according to claim 1, wherein the polycarbonate resin has a glass transition point of 115 to 160 ° C and an Abbe number of 43 to 35.
The optical lens according to claim 1 , wherein the polycarbonate resin has a photoelastic coefficient of 50 × 10 −12 Pa −1 to 30 × 10 −12 Pa −1 .
2. The optical lens according to claim 1, wherein the refractive index of the polycarbonate resin is 1.53 to 1.55.
The optical lens according to claim 1, which is a diffractive lens.
The diffractive lens has a thickness of 0.05 to 3.0 mm, an annular diffraction grating depth of 5 to 20 μm, an effective radius of the lens portion of 1.0 to 20.0 mm, a number of ring zones of 5 to 25, and a minimum ring zone pitch of 5 to 20 μm. The optical lens according to claim 6, which is an aspherical diffractive lens having a concave curvature radius of 0.1 to 10.0 mm and a diameter of 1.0 to 30.0 mm.