WO2024225099A1 - Polycarbonate resin and optical member using said resin - Google Patents

Abstract

[Problem] The first purpose of the present invention is to provide a polycarbonate resin that has excellent fluidity and has a small orientation birefringence.　The second purpose of the present invention is, in addition to the first purpose, to further provide a polycarbonate resin that has a high Abbe number and has a small orientation birefringence and a small photoelastic coefficient.　The third purpose of the present invention is, in addition to the first purpose, to further provide a polycarbonate resin that has a small orientation birefringence and has a high refractive index and a high glass transition temperature. [Solution] This polycarbonate resin includes a unit that is represented by formula (1) and/or formula (2), and a unit that is represented by formula (3), wherein the weight average molecular weight Mw is 10,000 to 55,000.　(In formula (3), R¹-R⁴ each independently represent a hydrogen atom or a C1-10 hydrocarbon group.)

Description

Polycarbonate resin and optical member using said resin

The present invention relates to polycarbonate resin and optical components using the resin.

Glass, which has traditionally been used as a material for optical systems, is capable of achieving the various optical properties required and has excellent environmental resistance, but it has the problem of being difficult to process. In response to this, resins, which are cheaper than glass materials and have excellent processability, have begun to be used for optical components.

Patent Document 1 describes an optical lens with a high refractive index and low orientation birefringence, made of a polycarbonate resin having a structure of pentacyclopentadecanedimethanol (hereinafter sometimes abbreviated as PCPDM) and 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene (hereinafter sometimes abbreviated as BPEF).

In addition, in the optical design of optical units, it is known that chromatic aberration is corrected by combining and using multiple lenses with different Abbe numbers. For example, chromatic aberration is corrected by combining a lens made of alicyclic polyolefin resin with a low refractive index and high Abbe number with a lens made of polycarbonate resin (nd = 1.59, νd = 31) made of bisphenol A with a high refractive index and low Abbe number. In recent years, there has been active development of resins with high refractive index and low Abbe number, and as a result, the demand for resins with high Abbe number is also increasing. In addition, polycarbonate resin from bisphenol A obtained by reacting 2,2-bis(4-hydroxyphenyl)propane (commonly known as bisphenol A) with phosgene or carbonate ester has excellent heat resistance and transparency, and also has excellent mechanical properties such as impact resistance, so it is widely used not only as a structural material but also as an optical material for optical disk substrates, various lenses, prisms, optical fibers, etc. However, polycarbonate resins made from bisphenol A have the problem of large birefringence due to molecular orientation and residual stress during molding. Therefore, with the recent expansion of optical material applications, there is a strong demand for the development of materials with even lower birefringence. For example, Patent Document 2 describes a polycarbonate resin that has a high Abbe number but a low photoelastic coefficient, which is produced by copolymerizing bisphenol A and PCPDM. In addition, Patent Document 3 proposes a method for producing a carbonate derivative without using a base by subjecting halogenated methane and a specific amount of a hydroxyl group-containing compound to a photoreaction in the presence of oxygen, and cites a copolymerized polycarbonate of BPEF and PCPDM as an example of the production method.

JP 2005-241962 A JP 2000-302860 A WO2020/100977

However, when attempting to apply the polycarbonate resin having the above-mentioned PCPDM and BPEF structure to thin-walled optical components such as imaging lenses, it was difficult to mold, and further improvement in the orientation birefringence was also required. In addition, the above-mentioned polycarbonate resin made of bisphenol A and PCPDM had issues such as room for improvement in the photoelastic coefficient, large orientation birefringence, and low refractive index and glass transition temperature. Furthermore, the molecular weight of the obtained resin was high, making it unsuitable for injection molding applications and unable to be used for thin-walled optical components such as imaging lenses. In addition, the weight-average molecular weight of the above-mentioned BPEF and PCPDM copolymer polycarbonate is extremely low at 3,360, and it cannot be said to be a sufficient polymer for use as a structural or optical material.

The first object of the present invention is to provide a polycarbonate resin that has excellent flowability and small orientation birefringence.

The second object of the present invention is to provide a polycarbonate resin that, in addition to the first object, has a high Abbe number and a small orientation birefringence and photoelastic coefficient.

The third object of the present invention is to provide a polycarbonate resin that, in addition to the first object, has a small orientation birefringence, a high refractive index, and a high glass transition temperature.

The inventors have discovered that the above problems can be solved by the present invention, which has the following features:

That is, the present invention is as follows.
Aspect 1
A polycarbonate resin containing a unit represented by formula (1) and/or formula (2) and a unit represented by formula (3), and having a weight average molecular weight Mw of 10,000 to 55,000.

(In the formula, R ¹ to R ⁴ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms.)
Aspect 2
The polycarbonate resin according to embodiment 1, wherein R ¹ to R ⁴ in formula (3) are hydrogen atoms.
Aspect 3
The polycarbonate resin according to aspect 1 or 2, wherein a molar ratio of the unit represented by the formula (1) and/or the formula (2) to the unit represented by the formula (3) is 99:1 to 1:99.
Aspect 4
A polycarbonate resin according to aspect 3, wherein a molar ratio of the units represented by the formula (1) and/or the formula (2) to the units represented by the formula (3) is 65:35 to 35:65.
Aspect 5
The polycarbonate resin according to aspect 1 or 2, wherein the absolute value of orientation birefringence is 7.0 × 10 ^-3 or less.
Aspect 6
3. The polycarbonate resin according to claim 1, having a photoelastic coefficient of less than 35×10 ⁻¹² Pa.
Aspect 7
A polycarbonate resin according to embodiment 1, comprising units represented by formula (1) and/or formula (2) in an amount of 50 mol % or more in all repeating units, and having a weight average molecular weight Mw of 10,000 to 50,000.
Aspect 8
8. The polycarbonate resin according to embodiment 7, wherein the unit represented by formula (3) is contained in more than 0% and not more than 50 mol % of all repeating units.
Aspect 9
A polycarbonate resin according to aspect 7 or 8, wherein a molar ratio of the units represented by the formula (1) and/or the formula (2) to the units represented by the formula (3) is from 99:1 to 50:50.
Aspect 10
9. The polycarbonate resin according to claim 7 or 8, which has a photoelastic coefficient of less than 25×10 ⁻¹² Pa.
Aspect 11
The polycarbonate resin according to aspect 7 or 8, having an Abbe number of 25.0 or more.
Aspect 12
A polycarbonate resin according to embodiment 1, which contains more than 0% and less than 50 mol% of units represented by formula (1) and/or formula (2) in all repeating units and has a weight average molecular weight Mw of 10,000 to 50,000.
Aspect 13
13. The polycarbonate resin according to claim 12, wherein the unit represented by formula (3) is contained in more than 50 mol % of all repeating units.
Aspect 14
The polycarbonate resin according to aspect 12 or 13, wherein a molar ratio of the units represented by the formula (1) and/or the formula (2) to the units represented by the formula (3) is from 1:99 to 49:51.
Aspect 15
14. The polycarbonate resin according to claim 12 or 13, wherein the absolute value of orientation birefringence is 3.0×10 ⁻³ or less.
Aspect 16
14. The polycarbonate resin according to claim 12 or 13, having a refractive index nd of 1.600 or more.
Aspect 17
14. The polycarbonate resin according to claim 12 or 13, having a glass transition temperature of 140° C. or higher.
Aspect 18
13. An optical member comprising the polycarbonate resin according to any one of claims 1, 2, 7, and 12.
Aspect 19
20. The optical member according to claim 18, wherein the optical member is an imaging lens or a sensing camera lens.
Aspect 20
20. The imaging lens or sensing camera lens according to claim 19, wherein the thickness of the central portion is 0.05 to 3.0 mm.

The polycarbonate resin of the present invention has excellent fluidity and small orientation birefringence. Therefore, it can be suitably used for thin optical components such as imaging lenses, and the industrial effects it provides are exceptional.

Moreover, the more preferred polycarbonate resin of the present invention has a high Abbe number, and further has a small orientation birefringence and photoelastic coefficient.

Furthermore, other more preferred polycarbonate resins of the present invention have small orientation birefringence, and high refractive index and glass transition temperature. Thus, the industrial effects of the polycarbonate resins of the present invention are exceptional.

The present invention will now be described in further detail.
First Embodiment
<Polycarbonate resin>
A polycarbonate resin containing a unit represented by formula (1) and/or formula (2) and a unit represented by formula (3), and having a weight average molecular weight Mw of 10,000 or more and 55,000 or less.

The polycarbonate resin of the present invention contains units represented by formula (1) and/or formula (2) and units represented by formula (3). The units represented by formula (1) and/or formula (2) are contained in the total repeating units at a ratio of more than 0 mol% to less than 100 mol%, and the units represented by formula (3) are contained in the total repeating units at a ratio of more than 0 mol% to less than 100 mol%. The units represented by formula (1) and/or formula (2) are preferably 10 mol% or more in the total repeating units, more preferably 20 mol% or more, and even more preferably 35 mol% or more. The units represented by formula (1) and/or formula (2) are preferably 90 mol% or less in the total repeating units, more preferably 80 mol% or less, and even more preferably 65 mol% or less. Within the above ranges, the orientation birefringence is small, and the balance of the refractive index, Abbe number, and photoelastic coefficient is excellent. In addition, the molar ratio of the units represented by formula (1) and/or formula (2) to the units represented by formula (3) is preferably 99:1 to 1:99, more preferably 80:20 to 20:80, and even more preferably 65:35 to 35:65. When the ratio of the units represented by formula (1) and/or formula (2) to the units represented by formula (3) is within the above range, the orientation birefringence is small, and the balance of the refractive index, Abbe number, and photoelastic coefficient is excellent.

In the above-mentioned definitions of mole percent and mole ratio, the units represented by formula (1) and/or formula (2) refer to the combined units of formula (1) and formula (2) when the polycarbonate resin contains units represented by formula (1) and formula (2), and refer to either one of the units contained when the polycarbonate resin contains units represented by formula (1) or formula (2).

(In the formula, R ¹ to R ⁴ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms.)
The polycarbonate resin of the present invention has a weight average molecular weight Mw of 10,000 or more, preferably 15,000 or more, and more preferably 20,000 or more. When the weight average molecular weight Mw is 10,000 or more, it is preferable that the resin has sufficient mechanical strength as a structural material or optical material. In addition, the weight average molecular weight Mw is 55,000 or less, more preferably 50,000 or less, even more preferably 40,000 or less, particularly preferably less than 35,000, and most preferably 30,000 or less. When the weight average molecular weight Mw is 55,000 or less, it is preferable that the resin has excellent flowability during injection molding. In particular, when the polycarbonate resin of the present invention is used for a thin-walled optical member such as an imaging lens, it is preferable that the resin has excellent flowability. The weight average molecular weight Mw can be measured by GPC using polystyrene with a known molecular weight as a standard sample and chloroform as a developing solvent.

The polycarbonate resin of the present invention preferably has an absolute value of orientation birefringence of 7.0×10 ⁻³ or less. If the absolute value of orientation birefringence is less than the above, it is preferable because birefringence due to molecular orientation is less likely to occur. The orientation birefringence is measured at a wavelength of 589 nm after cutting a test piece of 70 mm in length (45 mm between chucks) and 15 mm in width from a cast film of 100 μm in thickness obtained from a polycarbonate resin and stretching it twice at Tg+10° C.

The polycarbonate resin of the present invention preferably has a photoelastic coefficient of less than 35×10 ⁻¹² Pa. When the photoelastic coefficient is within the above range, birefringence due to stress is unlikely to occur, which is preferable. The photoelastic coefficient is measured by cutting a test piece 50 mm long and 10 mm wide from a cast film having a thickness of 100 μm obtained from the polycarbonate resin, and using a Spectroellipsometer M-220 manufactured by JASCO Corporation.

The polycarbonate resin of the present invention preferably has a refractive index nd of 1.540 or more, measured at a temperature of 20°C and a wavelength of 587.56 nm. A refractive index of this or more is preferable because it allows the optical component to be made thinner. The refractive index nd may also be 1.650 or less. A refractive index nd in the above range is preferable because it increases the degree of freedom in optical design when multiple lenses are used in combination.

The polycarbonate resin of the present invention preferably has an Abbe number of 25.0 or more. An Abbe number of this or more is preferable because it reduces the chromatic aberration of the optical member. The Abbe number may be 57.0 or less. An Abbe number in the above range is preferable because it increases the degree of freedom in optical design when multiple lenses are used in combination.

The Abbe number (νd) is calculated using the following formula from the refractive index at temperature: 20°C and wavelengths: 486.13 nm, 587.56 nm, and 656.27 nm.

νd=(nd-1)/(nF-nC)
nd: refractive index at a wavelength of 587.56 nm,
nF: refractive index at a wavelength of 486.13 nm,
nC: refers to the refractive index at a wavelength of 656.27 nm.

The polycarbonate resin of the present invention preferably has a glass transition temperature of 130°C or higher. A glass transition temperature in the above range is preferable because it increases the temperature range in which the optical component can be used. The glass transition temperature may be 160°C or lower. A glass transition temperature in the above range is preferable because it provides an excellent balance between heat resistance and moldability.

The polycarbonate resin of the present invention preferably has a thermal decomposition temperature of 370°C or higher. Thermal decomposition temperatures above this level are preferred because they provide excellent processing stability when molding the polycarbonate resin of the present invention and also cause little discoloration. The thermal decomposition temperature may also be 420°C or lower. The thermal decomposition temperature can be measured by TGA (thermogravimetric analysis) and is the temperature at which the weight is reduced by 5%.

The polycarbonate resin of the present invention preferably has a melt viscosity (Pa·s) of 30 or more at 260°C and a shear rate of 1,216/sec. Also, it is preferable that the melt viscosity (Pa·s) is 500 or less at 260°C and a shear rate of 1,216/sec. A melt viscosity in the above range is preferable because it has excellent moldability during injection molding. In particular, when injection molding thin-walled molded products such as lenses, the melt viscosity during molding is important, and a melt viscosity in the above range is preferable because it allows the desired lens shape to be obtained. The melt viscosity is measured using a Capilograph 1D manufactured by Toyo Seiki Co., Ltd. after drying the polycarbonate resin at 120°C for 4 hours.

The specific viscosity of the polycarbonate resin of the present invention is preferably 0.12 to 0.32. A specific viscosity of 0.12 to 0.32 provides an excellent balance between moldability and strength.

The specific viscosity is measured by measuring the specific viscosity (ηSP) of a solution of 0.7 g of polycarbonate resin dissolved in 100 ml of methylene chloride at 20°C using an Ostwald viscometer and calculating it from the following formula.

ηSP=(t-t0)/t0
[t0 is the number of seconds it takes for methylene chloride to fall, and t is the number of seconds it takes for the sample solution to fall]
In the polycarbonate resin of the present invention, R ¹ to R ⁴ in the above formula (3) each independently represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and the hydrocarbon group can be an alkyl group, Mention may be made of cycloalkyl groups and aryl groups.

Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, butyl, and t-butyl groups, with methyl and ethyl groups being preferred.

Cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and bicyclo[1.1.1]pentanyl groups.

Aryl groups include phenyl, tolyl, naphthyl, and xylyl groups, with phenyl being preferred.

R ¹ to R ⁴ are each independently preferably a hydrogen atom, a methyl group, or a phenyl group, more preferably a hydrogen atom or a phenyl group, R ¹ and R ² are each independently preferably a hydrogen atom or a phenyl group, and R ³ and R ⁴ are further preferably a hydrogen atom.

The repeating units represented by the above formula (1) and/or formula (2) are repeating units derived from pentacyclopentadecanedimethanol, and in the above formula (1) and/or formula (2), the repeating units may be pure substances or mixtures of the respective isomers in any ratio. Pentacyclopentadecanedimethanol includes the following structural formulas:

The repeating unit represented by the above formula (3) is preferably a repeating unit derived from 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene or 9,9-bis[4-(2-hydroxyethoxy)-3-phenylphenyl]fluorene, and more preferably a repeating unit derived from 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene.

The polycarbonate resin of the present invention may contain repeating units other than those represented by the above formulas (1) to (3) within the scope of obtaining the advantageous effects of the present invention. Examples of dihydroxy compounds that provide such repeating units include ethylene glycol, propanediol, butanediol, pentanediol, hexanediol, heptanediol, octanediol, nonanediol, tricyclo[5.2.1.0 ^2,6 ]decanedimethanol, cyclohexane-1,4-dimethanol, decalin-2,6-dimethanol, norbornane dimethanol, cyclopentane-1,3-dimethanol, isosorbide, isomannide, isoidide, hydroquinone, resorcinol, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, bis(4-hydroxyphenyl)diphenylmethane, 1,3-bis(2- ... Examples of such repeating units include 4,4'-(3,3,5-trimethylcyclohexylidene)bisphenol, 4,4'-cyclohexylidenebisphenol, 4,4'-(3-methylcyclohexylidene)bisphenol, bis(4-hydroxyphenyl)sulfone, bis(4-hydroxyphenyl)sulfide, biphenol, bisphenolfluorene, biscresolfluorene, 1,1'-bi-2-naphthol, and 2,2'-bis(2-hydroxyethoxy)-1,1'-binaphthalene. Such repeating units may account for 30 mol % or less of all repeating units.

In the polycarbonate resin of the present invention, the sum of the repeating units represented by the above formulas (1) to (3) is preferably 70 mol % or more of the total repeating units, more preferably 80 mol % or more, and even more preferably 90 mol % or more.

The terminals of the polycarbonate resin of the present invention are composed of hydroxyl groups or phenyl groups, and the proportion of terminal phenyl groups in the total terminals is preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, and even more preferably 95 mol% or more.

The polycarbonate resin of the present invention has a total light transmittance of 80% or more for a 1 mm thick molded body, more preferably 85% or more, and particularly preferably 88% or more. A 1 mm thick molded body can be obtained by subjecting the polycarbonate resin of the present invention to injection molding, hot press molding, melt extrusion molding, or the like.

The saturated water absorption of the polycarbonate resin of the present invention may be 0.10% to 0.70%, 0.20% to 0.70%, or 0.30% to 0.65%.

<Production method of polycarbonate resin>
The polycarbonate resin of the present invention is produced by a reaction means known per se for producing a normal polycarbonate resin, for example, a method of reacting a dihydroxy compound with a carbonate precursor such as a carbonic acid diester. Next, the basic means for these production methods will be briefly described.

The transesterification reaction using a carbonic acid diester as a carbonate precursor is carried out by heating and stirring a specified ratio of dihydroxy component with a carbonic acid diester under an inert gas atmosphere, and distilling off the resulting alcohol or phenol. The reaction temperature varies depending on the boiling point of the resulting alcohol or phenol, but is usually in the range of 120 to 300°C. The reaction is completed by reducing the pressure from the beginning and distilling off the resulting alcohol or phenol. If necessary, a terminal terminator, antioxidant, etc. may also be added.

The carbonic acid diester used in the transesterification reaction includes esters of aryl groups and aralkyl groups having 6 to 12 carbon atoms, which may be substituted. Specific examples include diphenyl carbonate, ditolyl carbonate, bis(chlorophenyl) carbonate, and m-cresyl carbonate. Of these, diphenyl carbonate is particularly preferred. The amount of diphenyl carbonate used is preferably 0.95 to 1.10 mol, more preferably 0.98 to 1.04 mol, per mol of the total of the dihydroxy compounds.

In addition, in the melt polymerization method, a polymerization catalyst can be used to increase the polymerization rate. Examples of such polymerization catalysts include alkali metal compounds, alkaline earth metal compounds, nitrogen-containing compounds, etc.

Such compounds preferably include organic acid salts, inorganic salts, oxides, hydroxides, hydrides, alkoxides, and quaternary ammonium hydroxides of alkali metals and alkaline earth metals, and these compounds can be used alone or in combination.

Examples of alkali metal compounds include sodium hydroxide, potassium hydroxide, cesium hydroxide, lithium hydroxide, sodium bicarbonate, sodium carbonate, potassium carbonate, cesium carbonate, lithium carbonate, sodium acetate, potassium acetate, cesium acetate, lithium acetate, sodium stearate, potassium stearate, cesium stearate, lithium stearate, sodium borohydride, sodium benzoate, potassium benzoate, cesium benzoate, lithium benzoate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, dilithium hydrogen phosphate, disodium phenylphosphate, disodium, dipotassium, dicesium and dilithium salts of bisphenol A, and sodium, potassium, cesium and lithium salts of phenol.

Examples of alkaline earth metal compounds include magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, magnesium carbonate, calcium carbonate, strontium carbonate, barium carbonate, magnesium diacetate, calcium diacetate, strontium diacetate, barium diacetate, etc.

Examples of nitrogen-containing compounds include quaternary ammonium hydroxides having alkyl or aryl groups, such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, and trimethylbenzylammonium hydroxide. Examples include bases or basic salts, such as tetramethylammonium borohydride, tetrabutylammonium borohydride, tetrabutylammonium tetraphenylborate, and tetraphenylammonium tetraphenylborate.

Other transesterification catalysts include salts of zinc, tin, zirconium, lead, titanium, germanium, antimony, and osmium, such as zinc acetate, zinc benzoate, zinc 2-ethylhexanoate, tin chloride (II), tin chloride (IV), tin acetate (II), tin acetate (IV), dibutyltin dilaurate, dibutyltin oxide, dibutyltin dimethoxide, zirconium acetylacetonate, zirconium oxyacetate, zirconium tetrabutoxide, lead acetate (II), lead acetate (IV) titanium tetrabutoxide (IV), etc. The catalysts used in WO 2011/010741 and JP 2017-179323 A may also be used.

Furthermore, a catalyst consisting of aluminum or a compound thereof and a phosphorus compound may be used. In that case, the amount is preferably 80 μmol to 1000 μmol, more preferably 90 μmol to 800 μmol, and even more preferably 100 μmol to 600 μmol per 1 mol of the dihydroxy component.

Aluminum salts include organic and inorganic salts of aluminum. Examples of organic salts of aluminum include aluminum carboxylates, specifically aluminum formate, aluminum acetate, aluminum propionate, aluminum oxalate, aluminum acrylate, aluminum laurate, aluminum stearate, aluminum benzoate, aluminum trichloroacetate, aluminum lactate, aluminum citrate, and aluminum salicylate. Examples of inorganic salts of aluminum include aluminum chloride, aluminum hydroxide, aluminum hydroxide chloride, aluminum carbonate, aluminum phosphate, and aluminum phosphonate. Examples of aluminum chelate compounds include aluminum acetylacetonate, aluminum acetylacetate, aluminum ethylacetoacetate, and aluminum ethylacetoacetate diisopropoxide.

Examples of phosphorus compounds include phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds, phosphonous acid compounds, phosphineous acid compounds, and phosphine compounds. Among these, phosphonic acid compounds, phosphinic acid compounds, and phosphine oxide compounds are particularly preferred, and phosphonic acid compounds are particularly preferred.

The amount of these polymerization catalysts used is preferably 0.1 μmol to 500 μmol, more preferably 0.5 μmol to 300 μmol, and even more preferably 1 μmol to 100 μmol per 1 mol of the dihydroxy component.

Also, a catalyst deactivator can be added in the later stages of the reaction. Known catalyst deactivators are effectively used as catalyst deactivators, and among these, ammonium salts and phosphonium salts of sulfonic acid are preferred. Furthermore, salts of dodecylbenzenesulfonic acid such as tetrabutylphosphonium dodecylbenzenesulfonate and salts of paratoluenesulfonic acid such as tetrabutylammonium paratoluenesulfonate are preferred.

As sulfonic acid esters, methyl benzenesulfonate, ethyl benzenesulfonate, butyl benzenesulfonate, octyl benzenesulfonate, phenyl benzenesulfonate, methyl paratoluenesulfonate, ethyl paratoluenesulfonate, butyl paratoluenesulfonate, octyl paratoluenesulfonate, phenyl paratoluenesulfonate, etc. are preferably used. Among these, tetrabutylphosphonium dodecylbenzenesulfonate is most preferably used.

When at least one polymerization catalyst selected from alkali metal compounds and/or alkaline earth metal compounds is used, the amount of the catalyst deactivator used is preferably 0.5 to 50 mol, more preferably 0.5 to 10 mol, and further preferably 0.8 to 5 mol, per mol of the catalyst.
<Optional Additives>
The polycarbonate resin of the present invention can be used as a resin composition by appropriately adding additives such as a mold release agent, a heat stabilizer (sometimes also called an antioxidant), an ultraviolet absorber, a bluing agent, an antistatic agent, a flame retardant, a plasticizer, a filler, an antioxidant, a light stabilizer, a polymerized metal deactivator, a lubricant, a surfactant, an antibacterial agent, etc. Specific examples of the mold release agent and heat stabilizer include those described in WO2011/010741.

Particularly preferred release agents include stearic acid monoglyceride, stearic acid triglyceride, pentaerythritol tetrastearate, and a mixture of stearic acid triglyceride and stearyl stearate. 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 taken as 100% by weight. The content of the release agent is preferably in the range of 0.005 to 2.0 parts by weight, more preferably in the range of 0.01 to 0.6 parts by weight, and even more preferably in the range of 0.02 to 0.5 parts by weight, relative to 100 parts by weight of polycarbonate resin.

Heat stabilizers include phosphorus-based heat stabilizers, sulfur-based heat stabilizers, and hindered phenol-based heat stabilizers.

Particularly preferred phosphorus-based heat stabilizers include tris(2,4-di-tert-butylphenyl)phosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite, distearyl pentaerythritol diphosphite, bis(2,4-dicumylphenyl)pentaerythritol diphosphite, cyclic neopentanetetraylbis(2,6-di-tert-butyl-4-methylphenyl phosphite), and bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite. The content of the phosphorus-based heat stabilizer is preferably 0.001 to 0.2 parts by weight per 100 parts by weight of the polycarbonate resin.

A particularly preferred sulfur-based heat stabilizer is pentaerythritol-tetrakis(3-laurylthiopropionate). The content of the sulfur-based heat stabilizer is preferably 0.001 to 0.2 parts by weight per 100 parts by weight of polycarbonate resin.

Preferred hindered phenol-based heat stabilizers include octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, pentaerythritol-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 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], 1,3,5-trimethyl-2,4,6-tris(3 ,5-di-tert-butyl-4-hydroxybenzyl)benzene, N,N-hexamethylenebis(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, 3,9-bis{1,1-dimethyl-2-[β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl}-2,4,8,10-tetraoxaspiro(5,5)undecane.

The content of the hindered phenol-based heat stabilizer is preferably 0.001 to 0.3 parts by weight per 100 parts by weight of polycarbonate resin.

Phosphorus-based heat stabilizers and hindered phenol-based heat stabilizers can also be used in combination.

As the ultraviolet absorbing agent, at least one ultraviolet absorbing agent selected from the group consisting of benzotriazole-based ultraviolet absorbing agents, benzophenone-based ultraviolet absorbing agents, triazine-based ultraviolet absorbing agents, cyclic iminoester-based ultraviolet absorbing agents, and cyanoacrylate-based ultraviolet absorbing agents is preferred.

Of the benzotriazole-based UV absorbers, 2-(2-hydroxy-5-tert-octylphenyl)benzotriazole and 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol] are more preferred.

Examples of benzophenone-based UV absorbers include 2-hydroxy-4-n-dodecyloxybenzophenone and 2-hydroxy-4-methoxy-2'-carboxybenzophenone.

Triazine-based UV absorbers include 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[(hexyl)oxy]-phenol, 2-(4,6-bis(2.4-dimethylphenyl)-1,3,5-triazin-2-yl)-5-[(octyl)oxy]-phenol, etc.

A particularly suitable cyclic iminoester UV absorber is 2,2'-p-phenylenebis(3,1-benzoxazin-4-one).

Cyanoacrylate-based UV absorbers include 1,3-bis-[(2'-cyano-3',3'-diphenylacryloyl)oxy]-2,2-bis[(2-cyano-3,3-diphenylacryloyl)oxy]methyl)propane and 1,3-bis-[(2-cyano-3,3-diphenylacryloyl)oxy]benzene.

The amount of UV absorber to be added is preferably 0.01 to 3.0 parts by weight per 100 parts by weight of polycarbonate resin, and within this range of addition, it is possible to impart sufficient weather resistance to molded polycarbonate resin products depending on the application.

<Optical components>
The optical member of the present invention contains the above-mentioned polycarbonate resin. Such optical members are not particularly limited as long as they are used for optical purposes in which the above-mentioned polycarbonate resin is useful, and examples of such optical members include optical disks, transparent conductive substrates, optical cards, sheets, films, optical fibers, lenses, prisms, optical films, substrates, optical filters, and hard coat films.

The optical member of the present invention may be composed of a resin composition containing the above-mentioned polycarbonate resin, and the resin composition may contain additives such as a heat stabilizer, a plasticizer, a light stabilizer, a polymerized metal deactivator, a flame retardant, a lubricant, an antistatic agent, a surfactant, an antibacterial agent, an ultraviolet absorber, a release agent, a bluing agent, a filler, and an antioxidant, as necessary.
<Optical lenses>
The optical member of the present invention may in particular be an optical lens. Examples of such an optical lens include imaging lenses for mobile phones, smartphones, tablet terminals, personal computers, digital cameras, video cameras, vehicle-mounted cameras, surveillance cameras, etc., and sensing camera lenses such as TOF cameras.

When the optical lens of the present invention is manufactured by injection molding, it is preferable to mold it under conditions of a cylinder temperature of 220 to 350°C and a mold temperature of 70 to 180°C. It is more preferable to mold it under conditions of a cylinder temperature of 240 to 300°C and a mold temperature of 80 to 170°C. If the cylinder temperature is higher than 350°C, the polycarbonate resin will decompose and discolor, and if it is lower than 230°C, the melt viscosity will be high and molding will be difficult. Also, if the mold temperature is higher than 180°C, it will be difficult to remove the molded piece made of polycarbonate resin from the mold. On the other hand, if the mold temperature is less than 70°C, the resin will harden too quickly in the mold during molding, making it difficult to control the shape of the molded piece and making it difficult to fully transfer the shape applied to the mold.

The optical lens of the present invention is preferably implemented as an aspherical lens if necessary. Aspherical lenses can reduce spherical aberration to essentially zero with a single lens, making it unnecessary to remove spherical aberration by combining multiple spherical lenses, which allows for weight reduction and reduced molding costs. As such, aspherical lenses are particularly useful as camera lenses, among other optical lenses.

In addition, since the polycarbonate resin of the present invention has high molding fluidity, it is useful as a material for optical lenses that are thin, small, and have complex shapes, and is particularly useful for imaging lenses and sensing camera lenses. Specific lens sizes include a central thickness of 0.05 to 3.0 mm, more preferably 0.05 to 2.0 mm, even more preferably 0.1 to 2.0 mm, and particularly preferably 0.1 to 1.0 mm. Also, the diameter is 1.0 mm to 20.0 mm, more preferably 1.0 to 10.0 mm, and even more preferably 3.0 to 10.0 mm. Also, the shape is preferably a meniscus lens with one convex side and the other concave side.

The lens made of the polycarbonate resin of the present invention can be formed by any method such as mold molding, cutting, polishing, laser processing, electric discharge processing, etching, etc. Among these, mold molding is more preferable in terms of production costs.
Second Embodiment
In the polycarbonate resin of the present invention, the matters described in the above-mentioned embodiment 1 are also applicable to embodiment 2 unless otherwise specified below.
<Polycarbonate resin>
The polycarbonate resin of the present invention contains a unit represented by formula (1) and/or formula (2) and a unit represented by formula (3), and preferably contains 50 mol% or more of the unit represented by formula (1) and/or formula (2) in the total repeating units. The unit represented by formula (1) and/or formula (2) is preferably contained in 90 mol% or less of the total repeating units, more preferably 80 mol% or less, and even more preferably 65 mol% or less. It is also preferable that the unit represented by formula (3) is contained in more than 0% and 50 mol% or less of the total repeating units. It is more preferable that the unit represented by formula (3) is contained in 10 mol% or more of the total repeating units, more preferably 20 mol% or more, and particularly preferably 35 mol% or more. The above range is preferable because it has a high Abbe number and is excellent in orientation birefringence and photoelastic coefficient. The molar ratio of the units represented by formula (1) and/or formula (2) to the units represented by formula (3) is preferably 99:1 to 50:50, more preferably 95:5 to 50:50, even more preferably 90:10 to 50:50, even more preferably 85:15 to 50:50, particularly preferably 80:20 to 50:50, and most preferably 65:35 to 50:50. When the ratio of the units represented by formula (1) and/or formula (2) to the units represented by formula (3) is within the above range, the Abbe number is high and the orientation birefringence and photoelastic coefficient are excellent, which is preferable.

(In the formula, R ¹ to R ⁴ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms.)
The polycarbonate resin of the present invention has a weight average molecular weight Mw of 10,000 or more, preferably 15,000 or more, and more preferably 20,000 or more. When the weight average molecular weight Mw is 10,000 or more, it is preferable that the resin has sufficient mechanical strength as a structural material or optical material. In addition, the weight average molecular weight Mw is 55,000 or less, more preferably 50,000 or less, even more preferably 40,000 or less, particularly preferably less than 35,000, and most preferably 30,000 or less. When the weight average molecular weight Mw is 50,000 or less, it is preferable that the resin has excellent flowability during injection molding. In particular, when the polycarbonate resin of the present invention is used for a thin-walled optical member such as an imaging lens, it is preferable that the resin has excellent flowability. The weight average molecular weight Mw can be measured by GPC using polystyrene with a known molecular weight as a standard sample and chloroform as a developing solvent.

The polycarbonate resin of the present invention preferably has an absolute value of orientation birefringence of 7.0×10 ⁻³ or less, more preferably 5.0×10 ⁻³ or less, even more preferably 3.0×10 ⁻³ or less, even more preferably 2.5×10 ⁻³ or less, particularly preferably 2.0×10 ⁻³ or less, and most preferably 1.5×10 ⁻³ or less. If the absolute value of orientation birefringence is less than the above, it is preferable because birefringence due to molecular orientation is less likely to occur. The orientation birefringence is measured at a wavelength of 589 nm after cutting a test piece of 70 mm in length (45 mm between chucks) and 15 mm in width from a cast film of 100 μm in thickness obtained from a polycarbonate resin and stretching it twice at Tg+10° C.

The polycarbonate resin of the present invention preferably has a photoelastic coefficient of less than 25×10 ⁻¹² Pa, and more preferably 20×10 ⁻¹² Pa or less. A photoelastic coefficient in the above range is preferable because it is less likely to cause birefringence due to stress. The photoelastic coefficient is measured by cutting a test piece 50 mm long and 10 mm wide from a cast film having a thickness of 100 μm obtained from the polycarbonate resin, and using a Spectroellipsometer M-220 manufactured by JASCO Corporation.

The polycarbonate resin of the present invention preferably has a refractive index nd measured at a temperature of 20°C and a wavelength of 587.56 nm of 1.540 or more, more preferably 1.550 or more, even more preferably 1.560 or more, even more preferably 1.570 or more, and particularly preferably 1.575 or more. A refractive index of the above or higher is preferable because it allows the optical member to be made thin. The refractive index nd may also be 1.610 or less, 1.600 or less, 1.590 or less, or 1.580 or less. A refractive index nd in the above range is preferable because it increases the degree of freedom in optical design when multiple lenses are used in combination.

The polycarbonate resin of the present invention preferably has an Abbe number of 25.0 or more, more preferably 28.0 or more, even more preferably 31.0 or more, even more preferably 34.0 or more, and particularly preferably 36.0 or more. An Abbe number of the above or higher is preferable because it reduces chromatic aberration of the optical member. The Abbe number may also be 57.0 or less, 55.0 or less, 50.0 or less, or 45.0 or less. An Abbe number in the above range is preferable because it increases the degree of freedom in optical design when multiple lenses are used in combination.

The Abbe number (νd) is calculated using the following formula from the refractive index at temperature: 20°C and wavelengths: 486.13 nm, 587.56 nm, and 656.27 nm.

νd=(nd-1)/(nF-nC)
nd: refractive index at a wavelength of 587.56 nm,
nF: refractive index at a wavelength of 486.13 nm,
nC: refers to the refractive index at a wavelength of 656.27 nm.

The polycarbonate resin of the present invention preferably has a glass transition temperature of 130°C or higher, more preferably 133°C or higher, and even more preferably 136°C or higher. A glass transition temperature in the above range is preferable because it increases the temperature range in which the optical component can be used. The glass transition temperature may also be 155°C or lower, 150°C or lower, 145°C or lower, or 140°C or lower. A glass transition temperature in the above range is preferable because it provides an excellent balance between heat resistance and moldability.

The polycarbonate resin of the present invention preferably has a thermal decomposition temperature of 370° C. or higher, more preferably 375° C. or higher. A thermal decomposition temperature of 370° C. or higher is preferable because the polycarbonate resin of the present invention has excellent processing stability when molded and is less likely to be discolored. The thermal decomposition temperature may be 420° C. or lower, or 400° C. or lower. The thermal decomposition temperature can be measured by TGA (thermogravimetric analysis) and is the temperature at which the weight is reduced by 5%.
The polycarbonate resin of the present invention preferably has a melt viscosity (Pa·s) of 30 or more at 260°C and a shear rate of 1,216/sec, more preferably 50 or more, and even more preferably 70 or more. The melt viscosity (Pa·s) at 260°C and a shear rate of 1,216/sec is preferably 500 or less, more preferably 400 or less, even more preferably 300 or less, and particularly preferably 200 or less. The melt viscosity in the above range is preferable because it has excellent moldability during injection molding. In particular, when injection molding a thin-walled molded product such as a lens, the melt viscosity during molding is important, and the melt viscosity in the above range is preferable because the desired lens shape can be obtained. The melt viscosity is measured by using a Capillograph 1D manufactured by Toyo Seiki Co., Ltd. after drying the polycarbonate resin at 120°C for 4 hours.

The specific viscosity of the polycarbonate resin of the present invention is preferably 0.12 to 0.32, and more preferably 0.18 to 0.30. A specific viscosity of 0.12 to 0.32 provides an excellent balance between moldability and strength.

The specific viscosity is measured by measuring the specific viscosity (ηSP) of a solution of 0.7 g of polycarbonate resin dissolved in 100 ml of methylene chloride at 20°C using an Ostwald viscometer and calculating it from the following formula.

ηSP=(t-t0)/t0
[t0 is the number of seconds it takes for methylene chloride to fall, and t is the number of seconds it takes for the sample solution to fall]
Third Embodiment
In the polycarbonate resin of the present invention, the matters described in the above-mentioned embodiment 1 are also applicable to embodiment 3 unless otherwise specified below.

<Polycarbonate resin>
The polycarbonate resin of the present invention contains a unit represented by formula (1) and/or formula (2) and a unit represented by formula (3), and preferably contains more than 0% and less than 50 mol% of the unit represented by formula (1) and/or formula (2) in the total repeating units. The unit represented by formula (1) and/or formula (2) is preferably contained in 10 mol% or more of the total repeating units, more preferably 20 mol% or more, and even more preferably 35 mol% or more and less than 50 mol%. It is also preferable that the unit represented by formula (3) is contained in more than 50 mol% of the total repeating units. The unit represented by formula (3) is preferably contained in 90 mol% or less of the total repeating units, more preferably 80 mol% or less, and even more preferably 65 mol% or less. The above range is preferable because the orientation birefringence is small, and the refractive index and glass transition temperature are high. Also, the molar ratio of the units represented by formula (1) and/or formula (2) to the units represented by formula (3) is preferably 1:99 to 49:51, more preferably 5:95 to 49:51, even more preferably 10:90 to 49:51, even more preferably 15:85 to 49:51, particularly preferably 20:80 to 49:51, and most preferably 35:65 to 49:51. When the ratio of the units represented by formula (1) and/or formula (2) to the units represented by formula (3) is within the above range, the orientation birefringence is small, and the refractive index and glass transition temperature are high, which is preferable.

(In the formula, R ¹ to R ⁴ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms.)
The polycarbonate resin of the present invention has a weight average molecular weight Mw of 10,000 or more, preferably 15,000 or more, and more preferably 20,000 or more. When the weight average molecular weight Mw is 10,000 or more, it is preferable that the resin has sufficient mechanical strength as a structural material or optical material. In addition, the weight average molecular weight Mw is 55,000 or less, more preferably 50,000 or less, even more preferably 40,000 or less, particularly preferably less than 35,000, and most preferably 30,000 or less. When the weight average molecular weight Mw is 50,000 or less, it is preferable that the resin has excellent flowability during injection molding. In particular, when the polycarbonate resin of the present invention is used for a thin-walled optical member such as an imaging lens, it is preferable that the resin has excellent flowability. The weight average molecular weight Mw can be measured by GPC using polystyrene with a known molecular weight as a standard sample and chloroform as a developing solvent.

The polycarbonate resin of the present invention preferably has an absolute value of orientation birefringence of 3.0×10 ⁻³ or less, more preferably 2.0×10 ⁻³ or less, even more preferably 1.0×10 ⁻³ or less, and even more preferably 0.5×10 ⁻³ or less. If the absolute value of orientation birefringence is less than the above, it is preferable because birefringence due to molecular orientation is less likely to occur. The orientation birefringence is measured at a wavelength of 589 nm after cutting a test piece of 70 mm in length (45 mm between chucks) and 15 mm in width from a cast film of 100 μm in thickness obtained from a polycarbonate resin and stretching it twice at Tg+10° C.

The polycarbonate resin of the present invention preferably has a photoelastic coefficient of less than 35×10 ⁻¹² Pa, more preferably 30×10 ⁻¹² Pa or less, and even more preferably 25×10 ⁻¹² Pa or less. When the photoelastic coefficient is within the above range, birefringence due to stress is unlikely to occur, which is preferable. The photoelastic coefficient is measured by cutting a test piece 50 mm long and 10 mm wide from a cast film having a thickness of 100 μm obtained from the polycarbonate resin, and using a Spectroellipsometer M-220 manufactured by JASCO Corporation.

The polycarbonate resin of the present invention preferably has a refractive index nd measured at a temperature of 20°C and a wavelength of 587.56 nm of 1.600 or more, more preferably 1.605 or more, even more preferably 1.610 or more, even more preferably 1.615 or more, and particularly preferably 1.620 or more. A refractive index of the above or higher is preferable because it allows the optical member to be made thin. The refractive index nd may also be 1.650 or less, 1.645 or less, 1.640 or less, or 1.635 or less. A refractive index nd in the above range is preferable because it increases the degree of freedom in optical design when multiple lenses are used in combination.

The polycarbonate resin of the present invention preferably has an Abbe number of 25.0 or more, and more preferably 30.0 or more. An Abbe number of this or more is preferable because it reduces the chromatic aberration of the optical member. The Abbe number may be 33.0 or less, or may be 32.0 or less. An Abbe number in the above range is preferable because it increases the degree of freedom in optical design when multiple lenses are used in combination.

The Abbe number (νd) is calculated using the following formula from the refractive index at temperature: 20°C and wavelengths: 486.13 nm, 587.56 nm, and 656.27 nm.

νd=(nd-1)/(nF-nC)
nd: refractive index at a wavelength of 587.56 nm,
nF: refractive index at a wavelength of 486.13 nm,
nC: refers to the refractive index at a wavelength of 656.27 nm.

The polycarbonate resin of the present invention preferably has a glass transition temperature of 138°C or higher, more preferably 140°C or higher, even more preferably 142°C or higher, and even more preferably 144°C or higher. A glass transition temperature in the above range is preferable because it increases the temperature range in which the optical component can be used. The glass transition temperature may also be 160°C or lower, 155°C or lower, or 150°C or lower. A glass transition temperature in the above range is preferable because it provides an excellent balance between heat resistance and moldability.

The polycarbonate resin of the present invention preferably has a thermal decomposition temperature of 370°C or higher, more preferably 375°C or higher, and even more preferably 380°C or higher. Thermal decomposition temperatures above the above range are preferred because they provide excellent processing stability when molding the polycarbonate resin of the present invention and cause little discoloration. The thermal decomposition temperature may be 420°C or lower, or 400°C or lower. The thermal decomposition temperature can be measured by TGA (thermogravimetric analysis) and is the temperature at which the weight has decreased by 5%.

The polycarbonate resin of the present invention preferably has a melt viscosity (Pa·s) of 30 or more at 260°C and a shear rate of 1,216/sec, more preferably 50 or more, and even more preferably 70 or more. The melt viscosity (Pa·s) at 260°C and a shear rate of 1,216/sec is preferably 500 or less, more preferably 400 or less, even more preferably 300 or less, and particularly preferably 200 or less. A melt viscosity in the above range is preferable because it has excellent moldability during injection molding. In particular, when injection molding a thin-walled molded product such as a lens, the melt viscosity during molding is important, and a melt viscosity in the above range is preferable because the desired lens shape can be obtained. The melt viscosity is measured using a Capilograph 1D manufactured by Toyo Seiki Co., Ltd. after drying the polycarbonate resin at 120°C for 4 hours.

The specific viscosity of the polycarbonate resin of the present invention is preferably 0.12 to 0.32, and more preferably 0.18 to 0.30. A specific viscosity of 0.12 to 0.32 provides an excellent balance between moldability and strength.

The specific viscosity is measured by measuring the specific viscosity (ηSP) of a solution of 0.7 g of polycarbonate resin dissolved in 100 ml of methylene chloride at 20°C using an Ostwald viscometer and calculating it from the following formula.

ηSP=(t-t0)/t0
[t0 is the number of seconds it takes for methylene chloride to fall, and t is the number of seconds it takes for the sample solution to fall] The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

The evaluation was carried out by the following method.
<Copolymerization ratio of polycarbonate resin>
The copolymerization ratio of each polycarbonate resin was calculated by measuring ¹ H NMR using a JEOL JNM-ECZ400S.
<Weight average molecular weight (Mw)
The weight average molecular weight Mw was measured using EcoSEC HLC-8320GPC manufactured by TOSOH under the conditions described below.

Detector: UV-8420, solvent: chloroform, column: TOSOH TSKgel SupermultiporeHZM-M × 3 + TSKgel guard column (4.6 × 200 nm), measurement temperature: 40°C, flow rate: 0.35 ml/min, injection amount: 5 μl, sample concentration: 1 mg/5 ml, standard sample: TSKstandard Polystyrene
<Refractive index>
A 3 mm thick test piece of each polycarbonate resin was prepared and polished, and then the refractive index nd (587.56 nm) was measured using a Kalnew precision refractometer KPR-2000 manufactured by Shimadzu Corporation.
<Abbe number>
The Abbe number (νd) was calculated from the refractive indexes at a temperature of 20° C. and wavelengths of 486.13 nm, 587.56 nm, and 656.27 nm using the following formula.

νd=(nd-1)/(nF-nC)
nd: refractive index at a wavelength of 587.56 nm,
nF: refractive index at a wavelength of 486.13 nm,
nC: refers to the refractive index at a wavelength of 656.27 nm.
<Absolute value of orientation birefringence (|Δn|)>
Polycarbonate resin was dissolved in methylene chloride, cast on a glass petri dish, and thoroughly dried to prepare a cast film with a thickness of 100 μm. A test piece with a length of 70 mm (chuck distance 45 mm) and a width of 15 mm was cut from the film. A film was cut out, stretched twice at Tg+10° C., and the phase difference (Re) at 589 nm was measured using an Ellipsometer M-220 manufactured by JASCO Corporation. The absolute value of the orientation birefringence (|Δn|) was calculated from the following formula: I asked.

|Δn|=|Re/d|
Δn: Orientation birefringence Re: Phase difference (nm)
d: thickness (nm)
<Photoelastic coefficient>
Polycarbonate resin was dissolved in methylene chloride, cast on a glass petri dish, and thoroughly dried to prepare a cast film with a thickness of 100 μm. A test piece with a length of 50 mm and a width of 10 mm was cut out from the film and measured using a JASCO Corporation ( The photoelastic coefficient was measured using an Ellipsometer M-220 manufactured by Epson Corporation.
<Glass transition temperature (Tg)>
The obtained polycarbonate resin was measured at a temperature rise rate of 20° C./min using a Discovery DSC 25Auto model manufactured by TA Instruments Japan Co., Ltd. The measurement was performed using 5 to 10 mg of the sample.
<Thermal decomposition temperature (Td-5)>
The polycarbonate resin thus obtained was measured at a heating rate of 20° C./min using an SDT650 model manufactured by TA Instruments Japan Co., Ltd., and the weight loss was determined as the weight loss of 5% based on the weight at 50° C. The temperature was measured. The sample was 3 to 4 mg.
<Melt viscosity (Pa s)>
The polycarbonate resin was dried at 120° C. for 4 hours, and then the melt viscosity was measured at 260° C. and a shear rate of 1,216/sec using a Capilograph 1D manufactured by Toyo Seiki Seisakusho Co., Ltd.
Example 1
87.70 g (0.20 mol) of 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene (hereinafter sometimes abbreviated as BPEF), 52.48 g (0.20 mol) of pentacyclopentadecane Dimethanol (hereinafter sometimes abbreviated as PCPDM), 89.12 g (0.42 mol) of diphenyl carbonate, and 17 μL of a 60 mmol/L aqueous solution of sodium bicarbonate (2.5 μmol of sodium bicarbonate) and 274 mmol/L of sodium bicarbonate were used as a catalyst. 227 μL of tetramethylammonium hydroxide aqueous solution (15 μmol of tetramethylammonium hydroxide) was heated to 180° C. in a nitrogen atmosphere to melt the solution. Then, the pressure inside the reactor was reduced to 20 kPa over 40 minutes while heating the reactor at 60° C./ The temperature was raised to 250° C. at a rate of 1000 rpm. After 70% of the theoretical amount of phenol was distilled off, the pressure inside the reactor was reduced to 133 Pa or less over 1 hour. The reaction was then terminated by stirring at 260° C. for 40 minutes with the pressure inside the reactor at 133 Pa or less, and the resin was taken out. The copolymerization ratio of the obtained polycarbonate resin derived from BPEF and PCPDM was measured by 1H NMR. The weight average molecular weight Mw, refractive index, Abbe number, glass transition temperature, thermal decomposition temperature, and orientation birefringence of the polycarbonate resin were The absolute value of the photoelastic coefficient and the melt viscosity were evaluated. The resin thus obtained was then dried at 120° C. for 4 hours, and then the bis(2,6-di-tert-butyl-4- 0.05% by mass of (methylphenyl)pentaerythritol diphosphite and 0.10% by mass of glycerin monostearate were added, and the mixture was pelletized using a vented φ15 mm twin-screw extruder. The pellets were dried at 120° C. for 4 hours, and then molded at a cylinder temperature of 260° C. and a mold temperature of Tg-5° C. of polycarbonate resin to produce lenses having a thickness of 0.3 mm, a convex curvature radius of 5 mm, a concave curvature radius of 4 mm, and a diameter of 5 mm. It was obtained by injection molding.
Example 2
A polycarbonate resin was produced in the same manner as in Example 1, except that the amount of BPEF charged was 52.62 g (0.12 mol) and the amount of PCPDM charged was 73.47 g (0.28 mol). The copolymerization ratio derived from BPEF and PCPDM was measured by 1H NMR. The weight average molecular weight Mw, refractive index, Abbe number, glass transition temperature, thermal decomposition temperature, absolute value of orientation birefringence, and photoelasticity of the polycarbonate resin were The coefficient and melt viscosity were evaluated. Thereafter, in the same manner as in Example 1, a lens having a thickness of 0.3 mm, a convex curvature radius of 5 mm, a concave curvature radius of 4 mm, and a diameter of 5 mm was obtained by injection molding.
Example 3
A polycarbonate resin was produced in the same manner as in Example 1, except that the amount of BPEF charged was 43.85 g (0.10 mol) and the amount of PCPDM charged was 78.72 g (0.30 mol). The copolymerization ratio derived from BPEF and PCPDM was measured by 1H NMR. The weight average molecular weight Mw, refractive index, Abbe number, glass transition temperature, thermal decomposition temperature, absolute value of orientation birefringence, and photoelasticity of the polycarbonate resin were The coefficient and melt viscosity were evaluated. Thereafter, in the same manner as in Example 1, a lens having a thickness of 0.3 mm, a convex surface curvature radius of 5 mm, a concave surface curvature radius of 4 mm, and a diameter of 5 mm was obtained by injection molding.
Example 4
A polycarbonate resin was produced in the same manner as in Example 1, except that the amount of BPEF charged was 8.78 g (0.02 mol) and the amount of PCPDM charged was 99.71 g (0.38 mol). The copolymerization ratio derived from BPEF and PCPDM was measured by 1H NMR. The weight average molecular weight Mw, refractive index, Abbe number, glass transition temperature, thermal decomposition temperature, absolute value of orientation birefringence, and photoelasticity of the polycarbonate resin were The coefficient and melt viscosity were evaluated. Thereafter, in the same manner as in Example 1, a lens having a thickness of 0.3 mm, a convex curvature radius of 5 mm, a concave curvature radius of 4 mm, and a diameter of 5 mm was obtained by injection molding.
<Comparative Example 1>
45.66 g (0.20 mol) of bisphenol A (hereinafter sometimes abbreviated as BPA), 52.48 g (0.20 mol) of PCPDM, 86.97 g (0.406 mol) of diphenyl carbonate, and carbonate as a catalyst 1.09 mg (12 μmol) of sodium hydrogen was heated to 180° C. in a nitrogen atmosphere to melt it. Then, the pressure inside the reactor was increased to 20 kPa (150 mmHg) and the temperature was increased to 200° C. at a rate of 60° C./hr. The reaction was continued for 40 minutes at that temperature. The temperature was then increased to 225° C. at a rate of 75° C./hr. After 40 minutes from the end of the temperature increase, the internal pressure of the reactor was reduced over a period of 1 hour while maintaining the temperature. was set to 133 Pa (1 mmHg) or less. Thereafter, the temperature was raised to 235° C. at a rate of 105° C./hr, and the reaction was carried out for a total of 6 hours under stirring. After the reaction was completed, nitrogen was blown into the reactor to return it to normal pressure, and the obtained resin was taken out. The copolymerization ratio of the polycarbonate resin derived from BPA and PCPDM was measured by 1H NMR. The weight average molecular weight Mw, refractive index, Abbe number, glass transition temperature, thermal decomposition temperature, absolute orientation birefringence of the polycarbonate resin were measured. The value, photoelastic coefficient and melt viscosity were evaluated. After that, injection molding of a lens having a thickness of 0.3 mm, a convex curvature radius of 5 mm, a concave curvature radius of 4 mm and a diameter of 5 mm was attempted in the same manner as in Example 1, but the resin Due to the high melt viscosity, it was not possible to mold a thin lens of that shape.
<Comparative Example 2>
A polycarbonate resin was produced in the same manner as in Comparative Example 1, except that the amount of BPA charged was 63.92 g (0.28 mol) and the amount of PCPDM charged was 31.49 g (0.12 mol). The copolymerization ratio derived from BPA and PCPDM was measured by 1H NMR. The weight average molecular weight Mw, refractive index, Abbe number, glass transition temperature, thermal decomposition temperature, absolute value of orientation birefringence, and photoelasticity of the polycarbonate resin were measured. The coefficient and melt viscosity were evaluated. After that, an attempt was made to injection mold a lens having a thickness of 0.3 mm, a convex curvature radius of 5 mm, a concave curvature radius of 4 mm, and a diameter of 5 mm in the same manner as in Example 1, but the melt viscosity of the resin was high. Therefore, it was not possible to mold a thin lens of this shape.
<Comparative Example 3>
A polycarbonate resin was produced in the same manner as in Comparative Example 1, except that the amount of BPA charged was 27.40 g (0.12 mol) and the amount of PCPDM charged was 73.47 g (0.28 mol). The copolymerization ratio derived from BPA and PCPDM was measured by 1H NMR. The weight average molecular weight Mw, refractive index, Abbe number, glass transition temperature, thermal decomposition temperature, absolute value of orientation birefringence, and photoelasticity of the polycarbonate resin were measured. The coefficient and melt viscosity were evaluated. After that, an attempt was made to injection mold a lens having a thickness of 0.3 mm, a convex curvature radius of 5 mm, a concave curvature radius of 4 mm, and a diameter of 5 mm in the same manner as in Example 1, but the melt viscosity of the resin was high. Therefore, it was not possible to mold a thin lens of this shape.
<Comparative Example 4>
87.70 g (0.20 mol) of BPEF, 52.48 g (0.20 mol) of PCPDM, 87.40 g (0.41 mol) of diphenyl carbonate, and 17 μL of a 60 mmol/L aqueous sodium bicarbonate solution (hydrogen carbonate) as a catalyst. Sodium (2.5 μmol) and 227 μL of a 274 mmol/L aqueous solution of tetramethylammonium hydroxide (15 μmol of tetramethylammonium hydroxide) were heated to 180° C. in a nitrogen atmosphere and melted. Then, the pressure inside the reactor was reduced to 20 kPa over a period of 40 minutes. The pressure was reduced to 100° C., and the temperature was raised to 250° C. at a rate of 60° C./hr. After 70% of the theoretical amount of phenol was distilled off, the pressure inside the reactor was reduced to 133 Pa or less over one hour. The mixture was stirred at 260° C. for 40 minutes under a pressure of 133 Pa or less to complete the reaction, and the resin was taken out. The copolymerization ratio of the obtained polycarbonate resin derived from BPEF and PCPDM was measured by 1H NMR. The weight average molecular weight Mw, refractive index, Abbe number, glass transition temperature, thermal decomposition temperature, and orientation birefringence of the polycarbonate resin were also measured. The absolute value, photoelastic coefficient and melt viscosity were evaluated. After that, injection molding of a lens having a thickness of 0.3 mm, a convex curvature radius of 5 mm, a concave curvature radius of 4 mm, and a diameter of 5 mm was attempted in the same manner as in Example 1, but the resin However, due to the high melt viscosity of the resin, it was not possible to mold a thin lens having the above shape.
<Comparative Example 5>
A polycarbonate resin was produced in the same manner as in Comparative Example 4, except that the amount of BPEF charged was 70.16 g (0.16 mol) and the amount of PCPDM charged was 62.97 g (0.24 mol). The copolymerization ratio derived from BPEF and PCPDM was measured by 1H NMR. The weight average molecular weight Mw, refractive index, Abbe number, glass transition temperature, thermal decomposition temperature, absolute value of orientation birefringence, and photoelasticity of the polycarbonate resin were The coefficient and melt viscosity were evaluated. After that, an attempt was made to injection mold a lens having a thickness of 0.3 mm, a convex curvature radius of 5 mm, a concave curvature radius of 4 mm, and a diameter of 5 mm in the same manner as in Example 1, but the melt viscosity of the resin was high. Therefore, it was not possible to mold a thin lens of this shape.
<Comparative Example 6>
A polycarbonate resin was produced in the same manner as in Comparative Example 4, except that the amount of BPEF charged was 52.62 g (0.12 mol) and the amount of PCPDM charged was 73.47 g (0.28 mol). The copolymerization ratio derived from BPEF and PCPDM was measured by 1H NMR. The weight average molecular weight Mw, refractive index, Abbe number, glass transition temperature, thermal decomposition temperature, absolute value of orientation birefringence, and photoelasticity of the polycarbonate resin were The coefficient and melt viscosity were evaluated. After that, injection molding of a lens with a thickness of 0.3 mm, a convex curvature radius of 5 mm, a concave curvature radius of 4 mm, and a diameter of 5 mm was attempted in the same manner as in Example 1, but the melt viscosity of the resin was high. Therefore, it was not possible to mold a thin lens of this shape.

In comparison with the comparative examples, the melt viscosity of the first to fourth examples of the present invention is low, and therefore the moldability during injection molding is excellent. In addition, since the orientation birefringence is excellent, birefringence due to molecular orientation is unlikely to occur when obtaining an optical component by injection molding or the like. In addition, since the photoelastic coefficient is small, birefringence due to stress is unlikely to occur when obtaining an optical component by injection molding or the like. Therefore, it is preferable because the birefringence of the optical component is small.
Example 5
166.64 g (0.38 mol) of 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene (hereinafter sometimes abbreviated as BPEF), 5.25 g (0.02 mol) of pentacyclopentadecanedimethanol (hereinafter sometimes abbreviated as PCPDM), 89.12 g (0.42 mol) of diphenyl carbonate, and 17 μL of a 60 mmol/L aqueous sodium hydrogen carbonate solution (2.5 μmol of sodium hydrogen carbonate) and 227 μL of a 274 mmol/L aqueous tetramethylammonium hydroxide solution (15 μmol of tetramethylammonium hydroxide) were heated to 180 ° C. under a nitrogen atmosphere and melted. Thereafter, the pressure inside the reactor was reduced to 20 kPa over 40 minutes, while the temperature was raised to 250 ° C. at a rate of 60 ° C./hr. After 70% of the theoretical amount of phenol was distilled out, the pressure inside the reactor was reduced to 133 Pa or less over 1 hour. Then, the reaction was terminated by stirring at 260° C. for 40 minutes at a pressure inside the reactor of 133 Pa or less, and the resin was taken out. The copolymerization ratio of the obtained polycarbonate resin derived from BPEF and PCPDM was measured by 1H NMR. The weight average molecular weight Mw, refractive index, Abbe number, glass transition temperature, thermal decomposition temperature, absolute value of orientation birefringence, photoelastic coefficient and melt viscosity of the polycarbonate resin were evaluated. Then, a lens having a thickness of 0.3 mm, a convex curvature radius of 5 mm, a concave curvature radius of 4 mm, and a φ5 mm was obtained by injection molding in the same manner as in Example 1.
Example 6
A polycarbonate resin was produced in the same manner as in Example 1, except that the amount of BPEF charged was 131.56 g (0.30 mol) and the amount of PCPDM charged was 26.24 g (0.10 mol). The copolymerization ratio of the obtained polycarbonate resin derived from BPEF and PCPDM was measured by 1H NMR. The weight average molecular weight Mw, refractive index, Abbe number, glass transition temperature, thermal decomposition temperature, absolute value of orientation birefringence, photoelastic coefficient and melt viscosity of the polycarbonate resin were evaluated. Thereafter, a lens having a thickness of 0.3 mm, a convex curvature radius of 5 mm, a concave curvature radius of 4 mm, and a φ5 mm was obtained by injection molding in the same manner as in Example 1.
Example 7
A polycarbonate resin was produced in the same manner as in Example 1, except that the amount of BPEF charged was 96.47 g (0.22 mol) and the amount of PCPDM charged was 47.23 g (0.18 mol). The copolymerization ratio of the obtained polycarbonate resin derived from BPEF and PCPDM was measured by 1H NMR. The weight average molecular weight Mw, refractive index, Abbe number, glass transition temperature, thermal decomposition temperature, absolute value of orientation birefringence, photoelastic coefficient and melt viscosity of the polycarbonate resin were evaluated. Thereafter, a lens having a thickness of 0.3 mm, a convex curvature radius of 5 mm, a concave curvature radius of 4 mm, and a φ5 mm was obtained by injection molding in the same manner as in Example 1.
<Comparative Example 7>
45.66g (0.20mol) of bisphenol A (hereinafter sometimes abbreviated as BPA), 52.48g (0.20mol) of PCPDM, 86.97g (0.406mol) of diphenyl carbonate, and 1.09mg (12μmol) of sodium hydrogen carbonate as a catalyst were heated to 180°C under a nitrogen atmosphere and melted. Thereafter, the reactor internal pressure was set to 20kPa (150mmHg) and the temperature was raised to 200°C at a rate of 60°C/hr, and the reaction was carried out while maintaining the temperature for 40 minutes. Further, the temperature was raised to 225°C at a rate of 75°C/hr, and 40 minutes after the end of the temperature rise, the reactor internal pressure was lowered to 133Pa (1mmHg) or less over 1 hour while maintaining the temperature. Then, the temperature was raised to 235°C at a rate of 105°C/hr, and the reaction was carried out under stirring for a total of 6 hours. After the reaction was completed, nitrogen was blown into the reactor to return to normal pressure, and the obtained resin was taken out. The copolymerization ratio of the obtained polycarbonate resin derived from BPA and PCPDM was measured by 1H NMR. The weight average molecular weight Mw, refractive index, Abbe number, glass transition temperature, thermal decomposition temperature, absolute value of orientation birefringence, photoelastic coefficient and melt viscosity of the polycarbonate resin were evaluated. Then, injection molding of a lens with a thickness of 0.3 mm, a convex curvature radius of 5 mm, a concave curvature radius of 4 mm, and a φ5 mm was attempted in the same manner as in Example 1, but the melt viscosity of the resin was high, so it was not possible to mold a thin lens of that shape.
<Comparative Example 8>
A polycarbonate resin was produced in the same manner as in Comparative Example 1, except that the amount of BPA charged was 63.92 g (0.28 mol) and the amount of PCPDM charged was 31.49 g (0.12 mol). The copolymerization ratio of the obtained polycarbonate resin derived from BPA and PCPDM was measured by 1H NMR. The weight average molecular weight Mw, refractive index, Abbe number, glass transition temperature, thermal decomposition temperature, absolute value of orientation birefringence, photoelastic coefficient and melt viscosity of the polycarbonate resin were evaluated. Thereafter, an injection molding of a lens having a thickness of 0.3 mm, a convex curvature radius of 5 mm, a concave curvature radius of 4 mm, and a φ5 mm was attempted in the same manner as in Example 1, but the melt viscosity of the resin was high, so it was not possible to mold a thin lens of that shape.
<Comparative Example 9>
A polycarbonate resin was produced in the same manner as in Comparative Example 1, except that the amount of BPA charged was 27.40 g (0.12 mol) and the amount of PCPDM charged was 73.47 g (0.28 mol). The copolymerization ratio of the obtained polycarbonate resin derived from BPA and PCPDM was measured by 1H NMR. The weight average molecular weight Mw, refractive index, Abbe number, glass transition temperature, thermal decomposition temperature, absolute value of orientation birefringence, photoelastic coefficient and melt viscosity of the polycarbonate resin were evaluated. Thereafter, injection molding of a lens with a thickness of 0.3 mm, a convex curvature radius of 5 mm, a concave curvature radius of 4 mm, and a φ5 mm was attempted in the same manner as in Example 1, but the melt viscosity of the resin was high, so it was not possible to mold a thin lens of that shape.
<Comparative Example 10>
A polycarbonate resin was produced in the same manner as in Comparative Example 4, except that the amount of BPEF charged was 122.79 g (0.28 mol) and the amount of PCPDM charged was 31.49 g (0.12 mol). The copolymerization ratio of the obtained polycarbonate resin derived from BPEF and PCPDM was measured by 1H NMR. The weight average molecular weight Mw, refractive index, Abbe number, glass transition temperature, thermal decomposition temperature, absolute value of orientation birefringence, photoelastic coefficient and melt viscosity of the polycarbonate resin were evaluated. Thereafter, injection molding of a lens having a thickness of 0.3 mm, a convex curvature radius of 5 mm, a concave curvature radius of 4 mm, and a φ5 mm was attempted in the same manner as in Example 1, but the melt viscosity of the resin was high, so it was not possible to mold a thin lens of that shape.

Compared to the comparative examples, Examples 5 to 7 of the present invention have a lower melt viscosity, and therefore have excellent moldability during injection molding. In addition, because they have excellent orientation birefringence, birefringence due to molecular orientation is unlikely to occur when obtaining optical components by injection molding, etc. In addition, because they have a high refractive index and glass transition temperature, they are preferable as optical components.

The polycarbonate resin of the present invention is used for optical materials, and can be used for optical members such as lenses, prisms, optical disks, transparent conductive substrates, optical cards, sheets, films, optical fibers, optical films, optical filters, and hard coat films. It is particularly useful for imaging lenses or sensing camera lenses, and is extremely useful for imaging lenses.

Claims (20)

A polycarbonate resin containing a unit represented by formula (1) and/or formula (2) and a unit represented by formula (3), and having a weight average molecular weight Mw of 10,000 to 55,000.

(In the formula, R ¹ to R ⁴ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms.) 2. The polycarbonate resin according to claim 1, wherein R ¹ to R ⁴ in the formula (3) are hydrogen atoms. The polycarbonate resin according to claim 1 or 2, in which the molar ratio of the units represented by formula (1) and/or formula (2) to the units represented by formula (3) is 99:1 to 1:99. The polycarbonate resin according to claim 3, wherein the molar ratio of the units represented by formula (1) and/or formula (2) to the units represented by formula (3) is 65:35 to 35:65. 3. The polycarbonate resin according to claim 1, wherein the absolute value of orientation birefringence is 7.0×10 ⁻³ or less. 3. The polycarbonate resin according to claim 1, which has a photoelastic coefficient of less than 35×10 ⁻¹² Pa. The polycarbonate resin according to claim 1, which contains 50 mol % or more of the units represented by formula (1) and/or formula (2) in all repeating units and has a weight average molecular weight Mw of 10,000 to 50,000. The polycarbonate resin according to claim 7, which contains more than 0% and not more than 50 mol% of the units represented by formula (3) in all repeating units. The polycarbonate resin according to claim 7 or 8, in which the molar ratio of the units represented by formula (1) and/or formula (2) to the units represented by formula (3) is 99:1 to 50:50. 9. The polycarbonate resin according to claim 7, which has a photoelastic coefficient of less than 25×10 ⁻¹² Pa. The polycarbonate resin according to claim 7 or 8, which has an Abbe number of 25.0 or more. The polycarbonate resin according to claim 1, which contains more than 0% and less than 50 mol% of units represented by formula (1) and/or formula (2) in all repeating units and has a weight average molecular weight Mw of 10,000 to 50,000. The polycarbonate resin according to claim 12, which contains more than 50 mol% of the units represented by formula (3) in all repeating units. The polycarbonate resin according to claim 12 or 13, in which the molar ratio of the units represented by formula (1) and/or formula (2) to the units represented by formula (3) is 1:99 to 49:51. The polycarbonate resin according to claim 12 or 13, wherein the absolute value of orientation birefringence is 3.0×10 ⁻³ or less. The polycarbonate resin according to claim 12 or 13, having a refractive index nd of 1.600 or more. The polycarbonate resin according to claim 12 or 13, having a glass transition temperature of 140°C or higher. An optical member made of the polycarbonate resin according to any one of claims 1, 2, 7 and 12. The optical member according to claim 18, wherein the optical member is an imaging lens or a sensing camera lens. The imaging lens or sensing camera lens according to claim 19, wherein the thickness of the center portion is 0.05 to 3.0 mm.