Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
2001-05-25
2002-11-19
Boykin, Terressa M. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
C264S176100, C385S129000, C385S130000, C428S412000, C430S270210, C528S198000
Reexamination Certificate
active
06482916
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a dyed molded article comprising a polycarbonate having particular repeating structural units.
BACKGROUND ART
Transparent resins, as compared with inorganic glasses, have advantages, for example, in that they are light, hardly broken and superior in processability; therefore, they are used in optical applications such as various lenses (e.g. eyeglass lens) and the like, as substitutes for inorganic glasses.
As such resins used in optical applications, many kinds have been known heretofore. For example, thermosetting resins using diethylene glycol bis(allyl carbonate) as a monomer, i.e. DAC resins are used in a large amount in general-purpose eyeglass lenses because they are superior in transparency and heat resistance, small in color aberration and easy to dye. These DAC resins, however, have had drawbacks in that they are low in refractive index (n
d
=1.50) and inferior in impact resistance.
Polycarbonates of 2,2-bis(4′-hydroxyphenyl)propane (so-called bisphenol A) (the polycarbonates are hereinafter referred to as BPA-PC), which are thermoplastic resins, are superior in transparency, impact resistance and heat resistance and have a relatively high refractive index; therefore, are in wide use as a resin for injection molded eyeglass lens. Polycarbonates typified by BPA-PC, however, are extremely difficult to dye by ordinary dyeing methods (e.g. dyeing with a disperse dye) and, in order to enable their dyeing, it has been necessary to form, on a lens to be dyed, a coat layer with a hard coat material which can be dyed, and then dye the coat layer (this has required complicated steps).
For dyeing a polycarbonate relatively easily, a method was proposed which comprises immersing a polycarbonate molded article to be dyed, in a solvent compound containing a dye, to dye the polycarbonate molded article directly (e.g. JP-A-8-104759). This method, however, can be viewed as a method of eroding the surface of a molded article (e.g. a lens) using an organic solvent and simultaneously dyeing the molded article with a dye or a pigment, and has been said to have an environmental problem in that the method uses an organic solvent. Moreover, the lens dyed by the above method is excessively eroded by the solvent compound at the surface, depending upon the dyeing conditions employed, and has reduced transparency; therefore, the dyed lens has no practical value.
In applications of transparent resin molded articles, for example, eyeglass lenses wherein fashionability is needed, there have been required not only optical properties (e.g. transparency and high refractive index), impact resistance, etc., but also being easily dyeable by a simple method. It is currently desired to develop a resin for optical application which is dyeable by a simple method, and a molded article obtained by dyeing such a resin.
The task of the present invention is to alleviate the above-mentioned problems and provide a dyed lens made of a polycarbonate having particular repeating structural units and high dyeability.
DISCLOSURE OF THE INVENTION
The present inventors made a study in order to solve the above-mentioned problems. As a result, the present inventors found out an easily dyeable aromatic polycarbonate. The finding has led to the completion of the present invention.
The present invention relates to the following.
(1) A dyed molded article obtained by dyeing a polycarbonate molded article having repeating structural units represented by the following formula (1-a):
(2) A dyed molded article according to the above (1), obtained by dyeing the molded article with a disperse dye in an aqueous medium.
(3) A dyed molded article according to the above (1) or (2), having a spectral transmittance of 10 to 90% relative to the spectral transmittance of the molded article at one or more wavelengths selected from 430 nm, 510 nm and 595 nm.
(4) A dyed molded article according to any of the above (1) to (3), wherein the molded article comprises a polycarbonate having a weight-average molecular weight of 10,000 to 300,000.
(5) An optical lens made of a dyed molded article set forth in any of the above (1) to (4).
(6) An optical lens according to the above (5), wherein the portion of the dyed molded article having a thickness of 1.5±0.5 mm shows a spectral transmittance of 5 to 85% at one or more wavelengths selected from 430 nm, 510 nm and 595 nm.
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention is described in detail below.
The present invention relates to a dyed molded article made of a polycarbonate having structural units represented by the above-shown formula (1-a).
The polycarbonate according to the present invention is obtained by reacting &agr;,&agr;′-bis(4-hydroxyphenyl)-1,3-diisopropylbenzene (hereinafter abbreviated to BPM or bisphenol M) represented by the following formula (1):
with a carbonate precursor (for example, a carbonic acid diester compound such as dimethyl carbonate, diethyl carbonate, diphenyl carbonate or the like, or a halogenated carbonyl compound such as phosgene or the like) to give rise to polymerization; and it is a known polymer described in, for example, U.S. Pat. No. 3,466,260.
That the polycarbonate of bisphenol M according to the present invention has excellent dyeability, is neither described in any of known patents (including U.S. Pat. No. 3,466,260), literatures and the like, nor known. The dyeability of the polycarbonate of bisphenol M has been found out for the first time as a result of investigations by the present inventors, and is quite surprising as compared with the conventional knowledge that polycarbonates have very inferior dyeability.
As the process for producing such a polycarbonate, there are mentioned, for example, a process described in the above-mentioned U.S. Pat. No. 3,466,260 and various known polymerization processes for polycarbonate production [for example, solution polymerization process, ester exchange process, or interfacial polymerization process described in Jikken Kagaku Koza, Fourth Edition (28), Polymer Synthesis, pp. 231-242, Maruzen Publication (1988)].
The polycarbonate used in the present invention is a polycarbonate having polycarbonate units as essential units, derived from the bisphenol M represented by the formula (1-a), or a copolycarbonate derived from the bisphenol M and other bisphenol. In the present specification, they are referred to as (co)polycarbonate. The polycarbonate used in the present invention may also be a blend of the (co)polycarbonate and an other known polycarbonate or copolycarbonate.
The molecular weight of the (co)polycarbonate according to the present invention is not critical and is ordinarily 10,000 to 300,000, preferably 20,000 to 250,000, more preferably 30,000 to 200,000 in terms of standard polystyrene-reduced weight-average molecular weight as measured by GPC (gel permeation chromatography).
The polydispersity index of the (co)polycarbonate, expressed as a ratio of weight-average molecular weight and number-average molecular weight is not critical and is preferably 1.5 to 20.0, more preferably 2.0 to 15.0.
In the polycarbonate according to the present invention, the terminal group may be reactive terminal group such as hydroxyl group, haloformate group, carbonic acid ester group or the like, or may be inactive terminal group blocked with a molecular weight modifier such as mentioned later. The terminal group is preferably inactive terminal group blocked with a molecular weight modifier.
In the (co)polycarbonate according to the present invention, the amount of the terminal group is not critical but is ordinarily 0.001 to 5 mole %, preferably 0.01 to 5 mole %, more preferably 0.1 to 3 mole % relative to the total moles of the structural units.
In producing the (co)polycarbonate of the present invention by the above-mentioned process, it is preferred to conduct polymerization in the presence of a molecular weight modifier for control of molecular weight. The molecular weight modifier is not critical as to the kind and can
Fujii Ken-ichi
Imai Masao
Otsuji Atsuo
Sugimoto Kenichi
Suzuki Rihiko
Boykin Terressa M.
Burns Doane , Swecker, Mathis LLP
Mitsui Chemicals Inc.
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