Thermoplastic resins and optical components

Abstract

To provide a thermoplastic resin that has an appropriate refractive index and Abbe number and that has excellent heat resistance and heat resistance stability, and an optical member that comprises the thermoplastic resin.SOLUTION: A thermoplastic resin comprises a structural unit represented by formula (1). (In formula (1), Y represents a divalent aliphatic group or alicyclic group, R1 and R2 each independently represent a hydrocarbon group, and W is a residue of a carbonyl group or a dicarboxylic acid from which a hydroxy group has been removed).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a thermoplastic resin having an appropriate refractive index and Abbe number, and excellent heat resistance and thermal stability, and an optical component made therefrom. [Background technology]

[0002] Cameras, video cameras, camera phones, video phones, and camera-equipped door phones all utilize imaging modules. In recent years, miniaturization has become particularly important for the optical systems used in these imaging modules. As optical systems are miniaturized, chromatic aberration becomes a major problem. It is known that chromatic aberration can be corrected by combining optical lens materials with high refractive index and low Abbe number (resulting in high dispersion) with optical lens materials with low refractive index and high Abbe number (resulting in low dispersion).

[0003] In recent years, the variety of optical elements used in imaging modules has increased, leading to a growing demand for resins for optical lenses with various balances of refractive index and Abbe number. However, there are few reports of thermoplastic resins that offer a good balance between low refractive index, high Abbe number, and low dispersion, as well as heat resistance, for optical lens materials.

[0004] For example, Patent Document 1 discloses a polycarbonate having a high Abbe number using 2,2-bis(4-hydroxycyclohexyl)propane. However, the 5% weight loss temperature, which is an indicator of heat stability, is insufficient for a thermoplastic resin, and improvement in heat resistance is required to introduce a structure having a hydrogenated bisphenol A skeleton that has excellent optical properties. The present invention aims to solve these problems and to provide a thermoplastic resin and an optical component containing the same that have an appropriate refractive index and Abbe number and excellent heat resistance and heat stability. [Prior art documents] [Patent Documents]

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The problem to be solved by the present invention is to provide a thermoplastic resin having an appropriate refractive index and Abbe number, and excellent heat resistance and heat stability, and an optical member containing the same.

Means for Solving the Problems

[0007] As a result of intensive studies to achieve this object, the present inventors have found that a thermoplastic resin having a specific structure can solve the above problems, and have reached the present invention. That is, the present invention is as follows.

[0008] ≪Aspect 1≫ A thermoplastic resin containing a structural unit represented by the following formula (1).

[0009]

Chemical formula

Chemical formula

Chemical formula

[0010] ≪Aspect 2≫ The thermoplastic resin according to Aspect 1, wherein the structural unit represented by the formula (1) is the following formula (4).

[0011] [Chemical formula] (wherein, R 1 and R 2 are the same as those in the above formula (1).)

[0012] <<Aspect 3>> The thermoplastic resin according to aspect 1 or 2, wherein the structural unit represented by the above formula (1) occupies 5 mol% to 100 mol% of all the structural units constituting the thermoplastic resin. <<Aspect 4>> In the above formula (1), R 1 and R 2 are ethyl groups; the thermoplastic resin according to aspects 1 to 3. <<Aspect 5>> The thermoplastic resin according to any one of aspects 1 to 4, further comprising a structural unit represented by the following formula (5).

[0013] [Chemical formula] (In formula (5), R 3 and R 4 are the same or different and each represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms; L 1 and L 2 each independently represents a divalent linking group; m and n each independently represent 0 or 1.)

[0014] <<Aspect 6>> In the above formula (1), W is the above formula (2); the thermoplastic resin according to any one of aspects 1 to 5. <<Aspect 7>> The thermoplastic resin according to any one of aspects 1 to 6, wherein the 5% weight loss temperature is 350 °C or higher. <<Aspect 8>> The thermoplastic resin according to any one of aspects 1 to 7, wherein the glass transition temperature is 125 to 180 °C. <<Aspect 9>> The thermoplastic resin according to any one of aspects 1 to 8, wherein the specific viscosity is 0.12 to 0.45. <<Aspect 10>> A thermoplastic resin according to any one of embodiments 1 to 9, wherein the refractive index is 1.450 to 1.650. <<Aspect 11>> A thermoplastic resin according to any one of embodiments 1 to 10, wherein the Abbe number is 20 to 65. <<Aspect 12>> An optical component formed from a thermoplastic resin according to any one of embodiments 1 to 11. <<Aspect 13>> An optical component as described in embodiment 12, which is an optical lens. [Effects of the Invention]

[0015] The thermoplastic resin of the present invention has excellent optical properties and a good balance between moldability, heat resistance, and heat stability. Therefore, it can be used in optical components such as optical lenses, prisms, optical discs, transparent conductive substrates, optical cards, sheets, films, optical fibers, optical films, optical filters, and hard coat films. It is particularly useful for optical lenses used in mobile phones, smartphones, tablet devices, personal computers, digital cameras, video cameras, in-vehicle cameras, or surveillance cameras, and therefore the industrial benefits it provides are exceptional. [Brief explanation of the drawing]

[0016] [Figure 1] This is the 1H NMR spectrum of the polycarbonate resin obtained in Example 1. [Figure 2] This is the 1H NMR spectrum of the polycarbonate resin obtained in Example 4. [Figure 3] This is the 1H NMR spectrum of the polycarbonate resin obtained in Example 5. [Modes for carrying out the invention]

[0017] The present invention will be described in more detail.

[0018] <Thermoplastic resin> The thermoplastic resin of the present invention is a thermoplastic resin comprising a constituent unit represented by the following formula (1).

[0019] [ka] (In formula (1), Y represents a divalent aliphatic or alicyclic group, R 1 and R 2 Each of these independently represents a hydrocarbon group, and W is at least one selected from the group represented by the following formulas (2) or (3). [ka] [ka] (In the formula, X represents a divalent linking group.)

[0020] In formula (1) above, Y represents a divalent aliphatic group or an alicyclic group. The divalent aliphatic group is preferably a branched alkylene group having 1 to 12 carbon atoms, more preferably 3 to 10 carbon atoms. The divalent alicyclic group is preferably a structure having an alicyclic group having 4 to 18 carbon atoms, more preferably 5 to 15 carbon atoms.

[0021] As specific examples of the structure of Y, those represented by the following structural formula (1-a) are preferred, and among these, an isopropylidene group (formula (4) below) is particularly preferred from a synthetic viewpoint.

[0022] [ka] (In equation (1-a), * indicates a binding site.)

[0023] [ka] (In the formula, R 1 and R 2 , W is the same as in equation (1) above.

[0024] In the above equation (1), R 1 and R 2Each of these groups independently represents a hydrocarbon group, preferably a linear alkyl group having 1 to 7 carbon atoms, a branched alkyl group having 3 to 7 carbon atoms, or an aryl group; more preferably a linear alkyl group having 1 to 7 carbon atoms or an aryl group; even more preferably a linear alkyl group having 1 to 7 carbon atoms; and particularly preferably a methyl group or an ethyl group.

[0025] In formula (1), W is at least one selected from the group represented by formulas (2) and (3). When W is formula (2), formula (1) becomes a carbonate unit, and when W is formula (3), formula (1) becomes an ester unit.

[0026] Formula (1) can be obtained from a dihydroxy compound and a carbonate precursor such as a carbonate ester, or from a dihydroxy compound and a dicarboxylic acid or its esterifying derivative.

[0027] In the thermoplastic resin of the present invention, which contains a constituent unit represented by formula (1), the constituent unit represented by formula (1) may be present in an amount of 5 mol% or more, 10 mol% or more, 15 mol% or more, 20 mol% or more, 25 mol% or more, or 30 mol% or more among all constituent units constituting the thermoplastic resin, and may be present in an amount of 100 mol% or less, 90 mol% or less, 80 mol% or less, 70 mol% or less, 60 mol% or less, or 50 mol% or less. In the thermoplastic resin of the present invention, the constituent unit represented by formula (1) may be present in an amount of preferably 10 mol% or more to 100 mol%, more preferably 20 mol% or more to 100 mol%, even more preferably 30 mol% or more to 100 mol%, and particularly preferably 40 mol% or more to 100 mol% among all constituent units constituting the thermoplastic resin. It is preferable that the proportion of the constituent unit represented by formula (1) be within the above range because it has an appropriate refractive index and Abbe number, and excellent heat resistance and heat stability.

[0028] The thermoplastic resin of the present invention may further include a constituent unit represented by the following formula (5).

[0029] [ka] (In formula (5), R 3 and R 4 L represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, either identical or different. 1 and L 2 Each of these independently represents a divalent linking group, and m and n independently represent either 0 or 1.

[0030] In equation (5) above, R 3 and R 4 Each of these independently represents a hydrocarbon group having 1 to 10 carbon atoms, which may contain a hydrogen atom or an aromatic group. Hydrogen atoms, methyl groups, phenyl groups, and naphthyl groups are preferred, hydrogen atoms, methyl groups, and phenyl groups are more preferred, and hydrogen atoms and methyl groups are even more preferred.

[0031] In the above formula (5), L 1 , L 2 Each of these independently represents a divalent linking group, preferably an alkylene group having 1 to 12 carbon atoms, more preferably an alkylene group having 1 to 4 carbon atoms, and even more preferably an ethylene group. 1 , L 2 The glass transition temperature (Tg) of the resin can be adjusted by adjusting the length of the linking group.

[0032] <Physical properties of thermoplastic resins> The 5% weight loss temperature of the thermoplastic resin of the present invention is the temperature at which the resin achieves a 5% weight loss under a nitrogen atmosphere at a heating rate of 20°C / min, and is preferably 350°C or higher, more preferably 360°C or higher, even more preferably 370°C or higher, and particularly preferably 380°C or higher. A 5% weight loss temperature of 350°C or higher indicates high heat stability.

[0033] The thermoplastic resin of the present invention may have a glass transition temperature (Tg) of 125°C or higher, 130°C or higher, 135°C or higher, or 140°C or higher, and may also have a glass transition temperature of 180°C or lower, 175°C or lower, 170°C or lower, 165°C or lower, or 160°C or lower. A glass transition temperature of 125 to 180°C is preferred, 130 to 170°C is more preferred, and 135 to 160°C is even more preferred. A glass transition temperature within the above range is preferable because it provides an excellent balance between heat resistance and moldability.

[0034] The specific viscosity of the thermoplastic resin of the present invention is preferably 0.12 to 0.45, more preferably 0.14 to 0.40, and even more preferably 0.16 to 0.40. A specific viscosity within the above range is preferable because it provides an excellent balance between moldability and mechanical strength.

[0035] The specific viscosity is measured by the specific viscosity (η) of a solution prepared by dissolving 0.7 g of thermoplastic resin in 100 ml of methylene chloride at 20°C. SP The viscometer is used to measure the viscometer and calculate the value from the following formula. Specific viscosity (η SP ) = (t-t0) / t0 (t0 is the number of seconds for the methylene chloride to fall, and t is the number of seconds for the sample solution to fall.)

[0036] The refractive index of the thermoplastic resin of the present invention, when measured at a temperature of 20°C and a wavelength of 587.56 nm, may be 1.450 or higher, 1.460 or higher, 1.470 or higher, 1.480 or higher, 1.490 or higher, or 1.500 or higher, and may also be 1.650 or lower, 1.640 or lower, 1.630 or lower, 1.620 or lower, 1.610 or lower, or 1.600 or lower.

[0037] The refractive index of the thermoplastic resin of the present invention is preferably 1.450 to 1.650, more preferably 1.460 to 1.600, even more preferably 1.470 to 1.590, particularly preferably 1.480 to 1.580, and most preferably 1.490 to 1.570.

[0038] The Abbe number of the thermoplastic resin of the present invention may be 20 or more, 21 or more, 22 or more, 23 or more, 24 or more, or 25 or more, and may be 65 or less, 64 or less, 63 or less, 62 or less, 61 or less, 60 or less, or 59 or less. The Abbe number (νd) is preferably 20 to 65, more preferably 35 to 63, and even more preferably 40 to 60.

[0039] Here, the Abbe number is calculated using the following formula based on the refractive index at a temperature of 20°C and wavelengths of 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: This refers to the refractive index at a wavelength of 656.27 nm.

[0040] <Raw materials for thermoplastic resins> (The diol component of formula (1)) The diol component that forms the raw material for formula (1) is mainly the diol component represented by the following formula (a), and may be used alone or in combination of two or more types.

[0041] [ka]

[0042] In equation (a), Y, R 1 and R 2 These are Y and R in equation (1). 1 and R 2 This is synonymous with the same thing, and the preferred range is also similar.

[0043] The following are representative examples of dihydroxy compounds represented by formula (a-1), but the raw materials used in formula (1) of the present invention are not limited to these. Note that Pr represents a propyl group and Bu represents a butyl group.

[0044] [ka]

[0045] Of these, formulas (a'-1) and (a'-2) below are more preferred, and formula (a'-2) below is even more preferred. These may be used individually or in combination of two or more.

[0046] [ka] [ka]

[0047] The diol represented by formula (a) is obtained by dehydrating and cyclizing a diketone represented by formula (6) below and a triol represented by formula (7) below.

[0048] [ka] [ka]

[0049] In equation (6), Y is the same as Y in equation (1), and the preferred range is also the same. In formula (7), R 5 R represents a hydrocarbon group. 5 The hydrocarbon group as represents a linear alkyl group having 1 to 7 carbon atoms, a branched alkyl group having 3 to 7 carbon atoms, or an aryl group. In one embodiment, R 5 R represents a linear alkyl group having 1 to 7 carbon atoms or a branched alkyl group having 3 to 7 carbon atoms. However, R 5 The hydrocarbon group does not contain an ether linkage.

[0050] R in equation (7) 5 For example, R in equation (1) above. 1 and R 2 This is synonymous with the same thing, and the preferred range is also similar.

[0051] (The carbonate component of formula (1) above) Examples of carbonate components used in the unit represented by formula (1) of the thermoplastic resin of the present invention include phosgene and carbonate esters. Examples of carbonate esters include esters of aryl groups, aralkyl groups, or alkyl groups having 1 to 4 carbon atoms, which may be substituted. Specifically, examples include diaryl carbonates such as diphenyl carbonate, dityl carbonate, bis(chlorophenyl) carbonate, bis(m-cresyl) carbonate, and dinaphthyl carbonate; dialkyl carbonates such as dimethyl carbonate, diethyl carbonate, dibutyl carbonate, and dicyclohexyl carbonate; alkylaryl carbonates such as ethylphenyl carbonate and cyclohexylphenyl carbonate; or diaryl carbonates such as divinyl carbonate, diisopropenyl carbonate, and dipropenyl carbonate. Among these, diaryl carbonates are preferred, and diphenyl carbonate is more preferred.

[0052] (The dicarboxylic acid component of formula (1) above) The dicarboxylic acid component used in the unit represented by formula (1) of the thermoplastic resin of the present invention is preferably a dicarboxylic acid represented by formula (b) or its ester-forming derivative.

[0053] [ka] In formula (b) above, X represents a divalent linking group.

[0054] The following are representative examples of dicarboxylic acids represented by formula (b) or their ester-forming derivatives, but the raw materials used in formula (b) of the present invention are not limited to these.

[0055] The dicarboxylic acid components used in the thermoplastic resin of the present invention include aliphatic dicarboxylic acid components such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, methylmalonic acid, and ethylmalonic acid; monocyclic aromatic dicarboxylic acid components such as phthalic acid, isophthalic acid, and terephthalic acid; 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, anthracenedicarboxylic acid, phenantradicarboxylic acid, 9,9-bis(carboxymethyl)fluorene, 9,9-bis(1-carboxyethyl)fluorene, 9,9-bis(1-carboxypropyl)fluorene, and 9,9-bis(1-carboxypropyl)fluorene. Examples include polycyclic aromatic dicarboxylic acid components such as s(2-carboxypropyl)fluorene, 9,9-bis(2-carboxy-1-methylethyl)fluorene, 9,9-bis(2-carboxy-1-methylpropyl)fluorene, 9,9-bis(2-carboxybutyl)fluorene, 9,9-bis(2-carboxy-1-methylbutyl)fluorene, 9,9-bis(5-carboxypentyl)fluorene, 9,9-bis(carboxycyclohexyl)fluorene, 2,2'-bis(carboxymethoxy)-1,1'-binaphthyl, biphenyl dicarboxylic acid components such as 2,2'-biphenyldicarboxylic acid, and alicyclic dicarboxylic acid components such as 1,4-cyclohexanedicarboxylic acid and 2,6-decalindicarboxylic acid. These may be used individually or in combination of two or more. In addition, acid chlorides and esters such as methyl esters, ethyl esters, and phenyl esters may be used as ester-forming derivatives.

[0056] (Components of formula (5) above) The thermoplastic resin of the present invention may further have the constituent units of formula (5), and the dihydroxy compound components that serve as raw materials for formula (5) are shown below. These may be used individually or in combination of two or more.

[0057] The dihydroxy compound component that serves as a raw material for formula (5) of the present invention is 9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-methylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-cyclohexylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-phenylphenyl)fluorene, 9,9-bis(4-hydroxyphenyl)fluorene, 9,9 Examples include bis(4-hydroxy-3-methylphenyl)fluorene, 9,9-bis(4-hydroxy-3-cyclohexylphenyl)fluorene, and 9,9-bis(4-hydroxy-3-phenylphenyl)fluorene, with 9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-phenylphenyl)fluorene, and 9,9-bis(4-hydroxy-3-methylphenyl)fluorene being particularly preferred. These may be used individually or in combination of two or more.

[0058] Furthermore, the thermoplastic resin of the present invention may contain additives such as heat stabilizers, plasticizers, light stabilizers, polymer metal deactivators, flame retardants, lubricants, antistatic agents, surfactants, antibacterial agents, antioxidants, ultraviolet absorbers, and mold release agents, as needed.

[0059] The thermoplastic resin of the present invention is produced, for example, by reacting a dihydroxy compound component with a carbonate precursor such as a diester carbonate, or by reacting a diol component with a dicarboxylic acid or its ester-forming derivative. Specific examples are shown below.

[0060] <Manufacturing method> (Method of manufacturing polycarbonate resin) When the thermoplastic resin of the present invention is a polycarbonate resin, it can be obtained by a known reaction method, for example, by reacting a dihydroxy compound component with a carbonate precursor by melt polymerization. When producing the polycarbonate resin, catalysts, end-terminating agents, antioxidants, etc., may be used as needed.

[0061] (Method of manufacturing polyester resin) If the thermoplastic resin of the present invention is a polyester resin, known reaction methods can be used, for example, by esterifying or transesterifying a dihydroxy compound component with a dicarboxylic acid or its ester-forming derivative, and then polycondensing the resulting reaction product to obtain a high molecular weight product of the desired molecular weight.

[0062] (Method for manufacturing polyester carbonate resin) When the thermoplastic resin of the present invention is a polyester carbonate resin, it can be produced by reacting a dihydroxy compound component and a dicarboxylic acid or its ester-forming derivative with a carbonate precursor such as a carbonate ester. The polymerization method can be the same as that used for the polycarbonate resin or polyester resin.

[0063] <Optical components> The optical component of the present invention is formed from the thermoplastic resin described above. Such optical components are not particularly limited as long as they are suitable for optical applications where the thermoplastic resin is useful, but examples include optical lenses, optical discs, transparent conductive substrates, optical cards, sheets, films, optical fibers, lenses, prisms, optical films, substrates, optical filters, hard coat films, and the like.

[0064] <Optical Lenses> In particular, optical lenses can be cited as optical components of the present invention. Examples of such optical lenses include optical lenses for mobile phones, smartphones, tablet devices, personal computers, digital cameras, video cameras, in-vehicle cameras, surveillance cameras, and the like.

[0065] The optical lens of the present invention can be formed and processed by any method such as injection molding, compression molding, injection compression molding, melt extrusion molding, and casting, but injection molding is particularly preferred.

[0066] The molding conditions for injection molding are not particularly limited, but the cylinder temperature of the molding machine is preferably 180 to 320°C, more preferably 220 to 300°C, and particularly preferably 240 to 280°C. The mold temperature is preferably 70 to 130°C, more preferably 80 to 125°C, and particularly preferably 90 to 120°C. The injection pressure is preferably 5 to 170 MPa, more preferably 50 to 160 MPa, and particularly preferably 100 to 150 MPa. [Examples]

[0067] The present invention will be described in more detail by the following examples, but the present invention is not limited thereto.

[0068] [Example 1] 6.6 parts by mass (20 ml%) of 2,2-bis(4-oxocyclohexyl)propane-bis(trimethylolpropane acetal) (hereinafter sometimes abbreviated as DSP), 24.56 parts by mass (80 ml%) of 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene (hereinafter sometimes abbreviated as BPEF), 15.15 parts by mass (101 ml%) of diphenyl carbonate (hereinafter sometimes abbreviated as DPC), and 2.94 × 10¹⁶ of sodium bicarbonate at a concentration of 60 mmol / L as a catalyst. -4 Part of mass (5.00×10 -3 %), tetramethylammonium hydroxide 1.92 × 10 at a concentration of 274 mmol / L -3 Part of mass (3.01×10 -2 %) was added and heated to 180°C under a nitrogen atmosphere to melt. Then, the pressure was adjusted to 20kPa over 5 minutes. The temperature was raised to 250°C at a heating rate of 40°C / hr, and after the phenol leaching rate reached 70%, the pressure was reduced to 40kPa / hr and the polymerization reaction was carried out until the predetermined power was reached. After the reaction was complete, the resin was removed from the flask. The obtained polycarbonate resin was then processed. 1Analysis by 1H NMR confirmed that the DSP component was introduced at a concentration of 20 ml relative to the total monomers, and the BPEF component at a concentration of 80 ml relative to the total monomers. The copolymerization ratio, specific viscosity, refractive index, Abbe number, Tg, and 5% weight loss temperature were evaluated using this polycarbonate resin, and the results are shown in Table 1.

[0069] [ka]

[0070] [Example 2] A polycarbonate resin was produced in the same manner as in Example 1, except that the ratio of DSP to BPEF was changed to 50:50 (mol%). The copolymerization ratio, specific viscosity, refractive index, Abbe number, Tg, and 5% weight loss temperature were evaluated using this thermoplastic resin, and the results are shown in Table 1.

[0071] [Example 3] A polycarbonate resin was produced in the same manner as in Example 1, except that the ratio of DSP to BPEF was changed to 70:30 (mol%). The copolymerization ratio, specific viscosity, refractive index, Abbe number, Tg, and 5% weight loss temperature were evaluated using this thermoplastic resin, and the results are shown in Table 1.

[0072] [Example 4] A polycarbonate resin was produced in the same manner as in Example 1, except that the monomer was changed to DSP only. The copolymerization ratio, specific viscosity, refractive index, Abbe number, Tg, and 5% weight loss temperature were evaluated using this thermoplastic resin, and the results are shown in Table 1.

[0073] [Example 5] A polycarbonate resin was produced in the same manner as in Example 1, except that 9,9-bis(4-hydroxy-3-methylphenyl)fluorene (hereinafter sometimes abbreviated as "BCF") was used instead of BPEF, and the ratio of DSP to BCF was changed to 80:20 (mol%). The copolymerization ratio, specific viscosity, refractive index, Abbe number, Tg, and 5% weight loss temperature were evaluated using this thermoplastic resin, and the results are shown in Table 1. BCF has the following chemical structure.

[0074] [ka]

[0075] [Comparative Example 1] A polycarbonate resin was produced in the same manner as in Example 1, except that hydrogenated bisphenol A (hereinafter sometimes abbreviated as "HBPA") was used instead of DSP, and the ratio of HBPA to BPEF was changed to 30:70 (mol%). The copolymerization ratio, specific viscosity, refractive index, Abbe number, Tg, and 5% weight loss temperature were evaluated using this thermoplastic resin, and the results are shown in Table 1. Note that HBPA has the following chemical structure.

[0076] [ka]

[0077] [Comparative Example 2] A polycarbonate resin was produced in the same manner as in Example 1, except that HBPA was used instead of DSP and the ratio of HBPA to BPEF was changed to 49:51 (mol%). The copolymerization ratio, specific viscosity, refractive index, Abbe number, Tg, and 5% weight loss temperature were evaluated using this thermoplastic resin, and the results are shown in Table 1. The obtained thermoplastic resin was evaluated using the following method.

[0078] <Specific viscosity measurement> The viscosity was determined using an Ostwald viscometer from a solution prepared by dissolving 0.7 g of the resin in 100 ml of methylene chloride at 20°C. Specific viscosity (η SP) = (t-t0) / t0 (t0 is the number of seconds for the methylene chloride to fall, and t is the number of seconds for the sample solution to fall.)

[0079] <Copolymerization ratio> The obtained resin was processed using JEOL Ltd.'s JNM-ECZ400S. 1 The composition ratio of each thermoplastic resin was calculated by 1H NMR measurement. CDCl3 was used as the solvent.

[0080] <Optical properties> (Refractive index) After preparing and polishing 3mm thick test specimens of each resin, the refractive index nd (587.56nm) at 20°C was measured using a Shimadzu KPR-2000 precision refractometer. (Abbe number) The measurement wavelengths for the Abbe number were calculated using the following formula based on the refractive indices at 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: This refers to the refractive index at a wavelength of 656.27 nm.

[0081] <Heat resistance> (Glass transition temperature (Tg)) The obtained resin was measured using a TA Instruments Discovery SDT650 differential thermal and thermogravimetric analyzer at a heating rate of 20°C / min. Approximately 5 mg of sample was used for the measurement.

[0082] <Heat resistance stability> (5% weight loss temperature) The obtained resin was measured using a TA Instruments Discovery SDT650 differential thermal and thermogravimetric analyzer under a nitrogen atmosphere at a heating rate of 20°C / min to determine the 5% weight loss temperature. The sample used for measurement was approximately 5 mg.

[0083] [Table 1]

[0084] The thermoplastic resins obtained in Examples 1-5 maintain excellent Abbe numbers comparable to HBPA, have a high 5% weight loss temperature of 370°C or higher, and a Tg between 125 and 180°C, resulting in an excellent balance between moldability and heat stability, making them superior as optical lenses. In contrast, the thermoplastic resins of the comparative examples have excellent optical properties and a high Tg of 140°C or higher, but have a low 5% weight loss temperature, resulting in problems with heat stability.

[0085] Structures like DSPs are effective for high-temperature stabilization because they can suppress thermal decomposition while maintaining excellent optical properties. [Industrial applicability]

[0086] The thermoplastic resin of the present invention has an appropriate refractive index and Abbe number, and is excellent in heat resistance and thermal stability, making it suitable for use as an optical material. Specifically, it can be used as an optical component such as optical lenses, prisms, optical discs, transparent conductive substrates, optical cards, sheets, films, optical fibers, optical films, optical filters, and hard coat films, and is particularly useful as an optical lens material.

Claims

1. A thermoplastic resin consisting only of the constituent units represented by the following formula (1), or a thermoplastic resin containing the constituent units represented by the following formula (1) and the constituent units represented by the following formula (5), wherein the constituent units represented by the following formula (1) account for 10 mol% to 90 mol% of the total constituent units of the thermoplastic resin, and the constituent units represented by the following formula (5) account for 90 mol% to 10 mol% of the total constituent units of the thermoplastic resin, and the thermoplastic resin having a 5% weight loss temperature of 350°C or higher. 【Chemistry 1】 (In formula (1), Y represents a divalent aliphatic or alicyclic group, R １ and R ２ Each of these independently represents a hydrocarbon group, and W is represented by the following formula (2). 【Chemistry 2】 【Transformation 3】 (In formula (5), R3 and R4 are the same or different, representing a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms; L1 and L2 each independently represent a divalent linking group; and m and n each independently represent 0 or 1.)

2. The thermoplastic resin according to claim 1, wherein the constituent unit represented by formula (1) is the following formula (4). 【Chemistry 4】 (In the formula, R １ and R ２ (W is the same as in equation (1) above.)

3. R in formula (1) １ and R ２ The thermoplastic resin according to claim 1, wherein the group is an ethyl group.

4. The thermoplastic resin according to claim 1, wherein the temperature at which the weight loss of 5% is 370°C or higher.

5. The thermoplastic resin according to claim 1, wherein the glass transition temperature is 125 to 180°C.

6. The thermoplastic resin according to claim 1, wherein the specific viscosity is 0.12 to 0.

45.

7. The thermoplastic resin according to claim 1, wherein the refractive index is 1.450 to 1.

650.

8. The thermoplastic resin according to claim 1, wherein the Abbe number is 20 to 65.

9. An optical member formed from the thermoplastic resin described in claim 1.

10. The optical component according to claim 9, which is an optical lens.

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