THERMOPLASTIC RESIN AND OPTICAL MEMBER CONTAINING SAME

Abstract

The purpose of the present invention is to provide: a polycarbonate resin which can satisfy all of a refractive index, an Abbe number, heat resistance, and birefringence; and an optical member containing the same. This thermoplastic resin contains repeating units represented by formula (1), formula (2) and formula (3), contains 60 mol % or more of repeating units represented by formula (1), and has a refractive index of more than 1.600 and not more than 1.660. (In formula (1), R.sup.1 to R.sup.4 each independently denote a hydrogen atom or a hydrocarbon group having 1-10 carbon atoms.) (In formula (3), n falls within the range 1-8, R.sup.5 and R.sup.6 each independently denote a hydrogen atom or a hydrocarbon group having 1-10 carbon atoms, and R.sup.7 denotes a hydrogen atom or an alkyl group having 1-3 carbon atoms.)

Claims

1. A thermoplastic resin comprising repeating units represented by Formula (1), Formula (2), and Formula (3), wherein the repeating unit represented by the Formula (1) is 60 mol % or greater and a refractive index is greater than 1.600 and 1.660 or less: ##STR00004## where in the Formula (1), R.sup.1 to R.sup.4 each independently represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and ##STR00005## where in the Formula (3), n is in a range of 1 to 8; R.sup.5 and R.sup.6 each independently represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms; and R.sup.7 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

2. The thermoplastic resin according to claim 1, wherein the repeating unit of the Formula (1) is 60 mol % or greater and 80 mol % or less.

3. The thermoplastic resin according to claim 1, wherein R.sup.1 to R.sup.4 in the Formula (1) are each a hydrogen atom.

4. The thermoplastic resin according to claim 1, wherein the repeating unit of the Formula (3) is a repeating unit derived from 4,4-(3,3,5-trimethylcyclohexylidene)bisphenol.

5. The thermoplastic resin according to claim 1, which has a glass transition temperature of 130 to 160 C.

6. The thermoplastic resin according to claim 1, which has an absolute value of orientation birefringence of 3.010.sup.3 or less.

7. The thermoplastic resin according to claim 1, which has an absolute value of orientation birefringence of 1.010.sup.3 or less.

8. The thermoplastic resin according to claim 1, which has an Abbe number of 24.0 to 29.0.

9. An optical member comprising the thermoplastic resin according to claim 1.

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

Description

EXAMPLES

[0118] Evaluations were carried out using the following methods.

<Thermoplastic Resin Composition>

[0119] The copolymerization ratio of each thermoplastic resin was calculated by H NMR measurement using a JNM-ECZ400S manufactured by JEOL Ltd.

<Refractive Index>

[0120] A 3 mm-thick test piece of each thermoplastic resin was prepared and polished, and then measured for refractive index nd (587.56 nm) using a Kalnew Precision Refractometer KPR-2000 manufactured by Shimadzu Corporation.

<Abbe Number>

[0121] The Abbe number (vd) was calculated at temperature: 20 C. and refractive indices at wavelengths: 486.13 nm, 587.56 nm, and 656.27 nm, using the following formula.

vd=(nd1)/(nFnC) [0122] nd: refractive index at wavelength of 587.56 nm [0123] nF: refractive index at wavelength of 486.13 nm [0124] nC: refractive index at wavelength of 656.27 nm

<Absolute Value of Orientation Birefringence>

[0125] The thermoplastic resin was dissolved in methylene chloride, then cast onto a glass petri dish, and sufficiently dried to produce a cast film having a thickness of 100 m. The film was stretched two-fold at Tg+10 C., the retardation (Re) at 589 nm was measured using an ellipsometer M-220 manufactured by JASCO Corporation, and an absolute value of the orientation birefringence (|n|) was determined by the following formula.

|n|=|Re/d| [0126] n: orientation birefringence [0127] Re: retardation (nm) [0128] d: thickness (nm)

Glass Transition Temperature (Tg)>

[0129] The obtained thermoplastic resin was measured with a Discovery DSC 25 Auto model manufactured by TA Instruments Japan Inc. at a temperature increase rate of 20 C./min. Samples were measured at 5 to 10 mg.

Example 1

[0130] 197.33 g (0.45 mol) of 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene (hereinafter, may be abbreviated as BPEF). 7.61 g (0.03 mol) of 3,9-bis(2-hydroxy-1,1-dimethylethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane (hereinafter, may be abbreviated as SPG), 7.76 g (0.03 mol) of 4,4-(3,3,5-trimethylcyclohexylidene)bisphenol (hereinafter, may be abbreviated as BisTMC), 109.25 g (0.51 mol) of diphenyl carbonate, and as a catalyst, 62.5 L of a sodium hydrogen carbonate aqueous solution at a concentration of 40 mmol/L (2.5 mol of sodium hydrogen carbonate) and 54.7 L of a tetramethylammonium hydroxide aqueous solution at a concentration of 274 mmol/L (15 mol of tetramethylammonium hydroxide) were heated and melted at 180 C. in a nitrogen atmosphere. The degree of pressure reduction was then adjusted to 20 kPa over a period of 10 minutes. The temperature was increased to 250 C. at a rate of 60 C./hr. After the outflowing amount of phenol reached 70%, the reactor internal pressure was lowered to 133 kPa over a period of 1 hour. Stirring was carried out for a total of 3.5 hours, and after the reaction was completed, the resin was removed. The copolymerization ratio of the obtained polycarbonate resin was measured by .sup.1H NMR. The refractive index, Abbe number, absolute value of orientation birefringence, and Tg of the polycarbonate resin were evaluated.

Examples 2 to 5

[0131] Except that the monomer ratio was changed so that the copolymerization ratio of BPEF to SPG to BisTMC was as described in Table 1, a polycarbonate resin was manufactured in the same manner as in Example 1.

Comparative Examples 1 to 4

[0132] Except that the monomer ratio was changed so that the copolymerization ratio of BPEF to SPG to BisTMC was as described in Table 1, a polycarbonate resin was manufactured in the same manner as in Example 1.

<Results>

[0133] The configurations of the Examples and Comparative Examples and the evaluation results thereof were summarized in the following Table 1.

TABLE-US-00001 TABLE 1 Evaluation results Birefringence Copolymerization ratio (mol %) Refractive Abbe |n| Tg BPEF SPG BisTMC index nd number d 10.sup.3 C. Example 1 90 5 5 1.629 25.0 0.7 146 Example 2 85 10 5 1.624 25.8 0.6 145 Example 3 75 15 10 1.615 25.5 0.2 144 Example 4 65 20 15 1.605 27.9 0.2 149 Example 5 60 10 30 1.603 28.2 0.3 149 Comparative Example 1 30 35 35 1.563 32.3 3.8 149 Comparative Example 2 20 45 35 1.546 34.9 4.4 145 Comparative Example 3 60 0 40 1.604 27.6 0.5 164 Comparative Example 4 60 40 0 1.590 30.3 0.1 129 [0134] BPEF: 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene [0135] SPG: 3,9-bis(2-hydroxy-1,1-dimethylethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane [0136] BisTMC: 4,4-(3,3,5-trimethylcyclohexylidene)bisphenol

[0137] Examples 1 to 5 were able to satisfy all of the refractive index of about 1.600 to 1.660, Abbe number, low birefringence, and heat resistance.

[0138] Comparative Examples 1 and 2 both exemplified a polycarbonate resin consisting of BPEF, SPG, and BisTMC. However, since the proportions of BPEF were small, the refractive indices and birefringence were insufficient compared to the Examples.

[0139] Comparative Example 3 exemplified a polycarbonate resin consisting of BPEF and BisTMC. However, since SPG was not contained, Tg was high compared to those of the Examples, and the polycarbonate resin was not suitable for use as a molding material.

[0140] Comparative Example 4 exemplified a polycarbonate resin consisting of BPEF and SPG. However, since BisTMC was not contained, Tg was low compared to those of the Examples, and heat resistance was insufficient.

INDUSTRIAL APPLICABILITY

[0141] The thermoplastic resin of the present invention is used in optical materials, can be used in optical members such as optical lenses, prisms, optical disks, transparent conductive boards, optical cards, sheets, films, optical fibers, optical membranes, optical filters, and hard coatings, and is very useful particularly in optical lenses.