JP3907377B2 - Optical element - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical optical element obtained from the composition you characterized by comprising a cholesteric liquid crystal compound as an additive with polylactic acid resin and the composition.
[0002]
[Prior art]
As an optical rotator for rotating the direction of linearly polarized light and elliptically polarized light such as a half-wave plate, an optical rotatory crystal plate and a phase difference plate, an optical rotator such as quartz or a birefringent crystal such as calcite It has been known. However, it is said that it is difficult to form a large area due to low productivity because it requires advanced technology and a lot of labor and time for crystal adjustment and polishing processing for accuracy improvement, and it is inflexible. There was a problem.
[0003]
[Problems to be solved by the invention]
An object of the present invention is to solve the prior art problems as described above, to provide an optical optical element obtained from the good composition and the composition of the moldability.
[0004]
[Means for Solving the Problems]
The present inventors have made intensive studies to solve the above problems, an optical optical element obtained from the composition ing comprising a cholesteric liquid crystal compound as an additive with polylactic acid resin and the composition, the above-mentioned problems The knowledge that it can be solved was found, and the present invention was completed based on this knowledge. That is, this invention is specified by the matter described in the following [1]- [13] .
[0005]
[ 1 ] A polylactic acid resin, from 0.001 to 30 composition characterized in that it comprises by weight% as an additive a cholesteric liquid crystal compound on the weight of the polylactic acid resin as a reference.
[0006]
[ 2 ] The composition described in [1], wherein the polylactic acid resin is polylactic acid .
[0007]
[ 3 ] The composition as described in [1] or [2] whose isomer content in the lactic acid origin repeating unit in a polylactic acid-type resin is 0-10 mol% .
[0008]
[ 4 ] A cholesteric liquid crystal compound, the compositions described in any one of which is a halogen compound of cholesterol [1] to [3].
[0009]
[ 5 ] Characterized in that it has optical rotation [1] to composition according to any one of [4].
[0010]
[ 6 ] The composition described in [ 5 ] having optical rotation in at least two axial directions .
[0011]
[ 7 ] An optical element obtained from the composition according to any one of [ 1 ] to [ 6 ] .
[0012]
[ 8 ] [ 7 ] An optical element, wherein the optical element is a light modulation element.
[0013]
[ 9 ] The optical element described in [ 8 ] , wherein the drive frequency of the light modulation is 1 MHz to 100 GHz.
[ 10 ] The optical element according to [ 8 ] or [ 9 ] , wherein the drive voltage for light modulation is 0.01 kV / m to 1 MV / m .
[0015]
[ 11 ] [ 7 ] - [ 10 ] An optical element having the fiber shape described in any one of [ 10 ] .
[0016]
[ 12 ] The optical element which has the shape of the film as described in any one of [ 7 ] - [ 10 ] .
[0017]
[ 13 ] [ 7 ] to [ 10 ] An optical element, which is a molded product, having a length to thickness ratio of 3 to 1 or more.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
[0022]
[Polylactic acid resin]
In the present invention, the polylactic acid-based resin is polylactic acid, a copolymer of lactic acid and a copolymerizable polyfunctional compound such as hydroxycarboxylic acid, a copolymer of lactic acid, a polyhydric alcohol and a polycarboxylic acid, and a mixture thereof. Is included.
Of these polylactic acid-based resins, polylactic acid which is a homopolymer is preferable, and L-polylactic acid is more preferable.
Moreover, in the case of a mixture, you may contain a compatibilizing agent. When the polylactic acid resin is a copolymer, the copolymer may be arranged in any form of a random copolymer, an alternating copolymer, a block copolymer, and a graft copolymer. Furthermore, these may be at least partially crosslinked with a polyvalent isocyanate such as xylylene diisocyanate or 2,4-tolylene diisocyanate, or a crosslinking agent such as a polysaccharide such as cellulose, acetyl cellulose or ethyl cellulose, and at least A part thereof may have any structure such as a linear shape, an annular shape, a branched shape, a star shape, or a three-dimensional network structure, and is not limited at all.
[0023]
[Lactic acid]
Examples of the lactic acid used as a raw material include L-lactic acid, D-lactic acid, DL-lactic acid, and mixtures thereof. When lactide, which is a cyclic dimer of lactic acid, is used as a raw material for a resin, L-lactide is used. , D-lactide, meso-lactide, or a mixture thereof.
A lactic acid polymer having a desired optical purity can be polymerized in various combinations of these optical isomer raw materials and depending on the reaction conditions. The isomer content is preferably 0 to 10%, and preferably 0 to 5%. % Is more preferable, and 0 to 2% is more preferable. For example, when the polylactic acid resin is L-polylactic acid, the content of D-lactic acid is preferably 0 to 10%, more preferably 0 to 5%, and still more preferably 0 to 2%.
[0024]
[Copolymerizable polyfunctional compound]
Examples of the copolymerizable polyfunctional compound include glycolic acid, dimethyl glycolic acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxypropanoic acid, 3-hydroxypropanoic acid, 2-hydroxy Valeric acid, 3-hydroxyvaleric acid, 4-hydroxyvaleric acid, 5-hydroxyvaleric acid, 2-hydroxycaproic acid, 3-hydroxycaproic acid, 4-hydroxycaproic acid, 5-hydroxycaproic acid, 6-hydroxycaproic acid Hydroxycarboxylic acids such as 6-hydroxymethylcaproic acid and mandelic acid; cyclic esters such as glycolide, β-methyl-δ-valerolactone, γ-valerolactone and ε-caprolactone; oxalic acid, malonic acid, succinic acid, glutar Acid, adipic acid, pimelic acid, azelaic acid, sebacic acid Polycarboxylic acids such as undecanedioic acid, dodecanedioic acid and terephthalic acid, and their anhydrides; ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3- Butanediol, 1,4-butanediol, 3-methyl-1,5-pentanediol, 2,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, neo Examples thereof include polyhydric alcohols such as pentyl glycol, tetramethylene glycol, and 1,4-hexanedimethanol; polysaccharides such as cellulose; aminocarboxylic acids such as α-amino acids;
These copolymerizable polyfunctional compounds may be one kind or a mixture of two or more kinds, and if they have asymmetric carbon, they may be L-form, D-form, and a mixture of any ratio thereof. Good.
[0025]
[Production method of polylactic acid resin]
The method for producing the polylactic acid resin used in the present invention is not particularly limited. For example, a method obtained by direct dehydration condensation of lactic acid described in JP-A-59-096123, JP-A-7-033861, etc. Or US Pat. No. 4,057,357, Polymer Bulletin, 14, 491-495 (1985), Makromol. Chem. 187, 1611-1628 (1986), etc., and the like, and the like by a ring-opening polymerization method using lactide, which is a cyclic dimer of lactic acid.
[0026]
[Weight average molecular weight of polylactic acid resin]
The weight average molecular weight (Mw) of the polylactic acid resin used in the present invention is not particularly limited, but is preferably 10,000 to 10,000,000, more preferably 30,000 to 3,000,000, and 50,000 to 1,000,000. Further preferred. The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the polylactic acid resin used in the present invention are the raw material type, solvent type, catalyst type and amount, reaction temperature, reaction time in the production method. The reaction system can be controlled to a desired one by appropriately selecting reaction conditions such as the degree of dehydration of the reaction system.
Since the polylactic acid resin used in the present invention has high transparency, it can be widely used as an optical element.
[0027]
[Optical rotation of polylactic acid resin]
Since the polylactic acid-based resin used in the present invention has an asymmetric carbon in the main chain, high optical rotation can be expressed by appropriate structure control.
When used as an optical rotator, the optical rotation is not particularly limited, but it is usually preferably 10 to 10000 ° / 1 mm.
[0028]
[Additive]
The polylactic acid resin used in the present invention is characterized by containing an additive for the purpose of improving optical rotation and other physical properties.
Specific examples of such additives include, for example, glycolic acid, dimethyl glycolic acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxypropanoic acid, 3-hydroxypropanoic acid, 2-hydroxy Valeric acid, 3-hydroxyvaleric acid, 4-hydroxyvaleric acid, 5-hydroxyvaleric acid, 2-hydroxycaproic acid, 3-hydroxycaproic acid, 4-hydroxycaproic acid, 5-hydroxycaproic acid, 6-hydroxycaproic acid , Hydroxycarboxylic acids such as 6-hydroxymethylcaproic acid and mandelic acid;
Oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, polycarboxylic acid such as terephthalic acid, and their anhydrides and their monoamides And their diamides;
Ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 3-methyl-1,5-pentanediol, 2, Polyhydric alcohols such as 3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, neopentyl glycol, tetramethylene glycol, 1,4-hexanedimethanol, glycerol;
Polyvalent amines such as ethylenediamine, propanediamine, butanediamine, pentanediamine, hexanediamine, heptanediamine, octanediamine, nonanediamine, decanediamine;
Glyceraldehyde, erythrose, threose, ribose, arabinose, xylose, lyxose, allose, altrose, glucose, mannose, gulose, idose, galactose, talose, fructose, 2-deoxyribose;
Alditols such as mannitol and glucitol;
Inositol, myo-inositol; monosaccharides such as glucosamine, disaccharides such as sucrose, lactose, maltose, cellobiose, trehalose, trisaccharides such as raffinose, starch, amylose, amylopectin, cellulose, lignin, chitin, chitosan, linaken, pectin, heparin Polysaccharides and derivatives thereof such as alanine, valine, leucine, isoleucine, methionine, tryptophan, phenylalanine, proline, glycine, serine, threonine, cysteine, tyrosine, asparagine, glutamine, lysine, histidine, arginine, aspartic acid, glutamic acid, L -Ornithine, β-alanine, γ-aminobutyric acid, ω-ester of acidic amino acid, N-substituted basic amino acid, aspartic acid-L-phenylalanine dimer ( Suparutemu) amino acids and amino acid derivatives such as, L- amino acids such as cysteic acid or the like, amino acids such as α- amino acid, polylysine, polyglutamic acid, polyaspartic acid, polypeptides and derivatives thereof such as proteins;
Cholesteryl bromide, cholesteryl-n-hexyl ether, cholesteryl-n-heptanoate, cholesteryl-n-heptyl carbonate, cholesteryl-n-heptyl mercaptocarbonate, cholesteryl benzoate, cholesteryl-ω-phenylheptanoate, cholesteryl elcate, 4-n-dodecyl Cholesterol halides such as oxy-1-naphthyridine-cholesteryl-p-aminobenzoate, fatty acid esters, carbonate esters, N- (4-ethoxybenzylidene) -4- (2-methylbutyl) aniline, 4-ethoxy-4′- (2-Methylbutyl) azobenzene, 4-ethoxy-4 ′-(2-methylbutyl) azoxybenzene, 4- (2-methylbutyl) benzoic acid-4′-n-hexyloxyphenyl ester 4-n-heptoxy-4 ′-(2-methylbutyloxycarbonyl) biphenyl, 4- [4- (2-methylbutyl) benzoyloxy] benzoic acid-4′-n-pentylphenyl ester, 4- [4- ( 2-Methylbutyl) benzoyloxy] benzoic acid-4′-cyanophenyl ester, 4- [4- (2-methylbutyl) benzoyloxy] benzoic acid-4′-nitrophenyl ester, 4- [4- (3-methylpentyl) ) Benzoyloxy] benzoic acid-4′-methylphenyl ester, 4- (2-methylbutyl) -4′-cyanobiphenyl, 4- (3-methylpentyl) -4′-cyanobiphenyl, 4- (3-methylpentyl) ) -4′-cyanobiphenyl, 4- [4- (2-methylbutyl) phenyl] benzoic acid-4′-butylphenyl ester, 4- [4 (2-Methylbutyl) phenyl] benzoic acid-4′-cyanophenyl ester, trans-4- (2-methylbutyl) cyanohexylcarboxylic acid-4′-cyanobiphenyl ester, 4-n-hexyloxybenzoic acid-4′- Examples thereof include liquid crystal compounds such as (2-methylbutoxycarbonyl) phenyl ester and 4- (4-methylbutyl) -4 ″ -cyano-p-terphenyl, and cholesteric liquid crystal compounds.
[0029]
[Composition ratio of additives]
The composition ratio of the additive added to the polylactic acid resin used in the present invention is not particularly limited as long as it can substantially function, but usually 0.001 to 0.001 based on the weight of the polylactic acid resin. 30% by weight, preferably 0.01-20% by weight, more preferably 0.1-10% by weight.
By adding these additives, for example, optical rotation can be imparted in at least two axial directions, and in this case, the additive is preferably a compound having optical activity.
[0030]
[Usage]
The optical element according to the present invention includes, for example, an optical rotator, a wave plate, a polarizing plate, an optical deflector, a retardation plate, a waveguide, a lens, an optical fiber, and an optical fiber in the fields of an optical communication system, an optical switching system, and an optical measurement system. Coating materials, light emitting elements, light modulating elements, optical amplifying elements, optical switches, optical shutters, dimmers, dimming panels, magneto-optical storage elements, optical memories, holograms and other recording media, optical arithmetic elements, barcodes, It can be used for display materials such as solar cells, photodetectors, semiconductor lasers, solid-state lasers, LEDs, ELs, spatial light modulators, wavelength conversion elements, optical isolators, photorefractive, PSHB, liquid crystal panels, and head-up displays. .
It can be used as an optical modulation element utilizing the optical rotation, the driving frequency is preferably 1 MHz to 100 GHz, and the driving voltage is preferably 0.01 kV / m to 1 MV / m.
Further, since it has optical rotation in at least two axial directions, it can be used as a more advanced optical element such as an arithmetic element.
When used as an optical element, it can be used as a form combined with another optical element such as another polarizing plate.
[0031]
[shape]
The shape of the optical element according to the present invention is not particularly limited, but is usually a shape such as a molded article such as a rod, a film, a sheet, a fiber, a filament, a strand, or the like. The film used in the present specification refers to a thin flat plate-shaped molded article, refers to a film having a thickness of less than 0.25 mm, and the sheet refers to a film thicker than this. Fiber refers to an elongated linear solid. Further, it can be used as a molded product having a length to thickness ratio of 3 to 1 or more.
[0032]
[Molding method]
The optical element according to the present invention is manufactured by a known molding method, specifically, an injection molding method, an extrusion molding method, a blow molding method, an inflation molding method, a vacuum molding method, a melt film forming method, a dry film forming method. Method, wet film forming method, melt spinning method, dry spinning method, wet spinning method and the like.
[0033]
[Processing into film]
When processing into a film shape, an unstretched film can be shape | molded, for example using the extruder etc. with which the polylactic acid-type resin was mounted | worn with a T die, a circular die, etc. Further, if necessary, the obtained unstretched film can be uniaxially stretched, by sequential biaxial stretching method of roll stretching and tenter stretching, simultaneous biaxial stretching method by tenter stretching, biaxial stretching method by tubular stretching, etc. A biaxially stretched film can be produced by stretching.
For example, a stretched film by sequential biaxial stretching combining roll stretching and tenter stretching is produced as follows. The polylactic acid resin is heat-treated at a temperature of 50 to 130 ° C., and dried and crystallized. Next, after melt-extruding at a temperature of 130 to 250 ° C. with an extruder equipped with a T die, the film is rapidly cooled with a casting roll of 60 ° C. or less to form a film. In this case, an air knife or an electrostatic application device is preferably used in order to improve the flatness by bringing the molten film into close contact with the roll. Next, the obtained film was passed through a take-up machine, and stretched 1.3 to 5 times, preferably 2 to 4 times at a temperature of 30 to 80 ° C. with a longitudinal stretching machine, and then 40 to 80 ° C. with a tenter. The film is stretched at a temperature of 1.3 to 5 times, preferably 2 to 4 times. When the stretched film needs to have heat resistance (heat shrinkage resistance), it is preferably subsequently heat-set in a tenter at a temperature of 80 to 150 ° C. for 3 to 120 seconds under tension.
[0034]
[Processing to fiber shape]
In the case of a fiber shape, it is kneaded and melted using an extruder or the like equipped with a spinning die and formed into a fiber through a spinneret. Furthermore, if necessary, the fiber can be stretched and oriented, and the oriented fiber can be annealed and further subjected to heat treatment. The spinning temperature may be higher than the melting point of the resin and lower than the decomposition temperature. Usually, it is preferably 120 ° C to 250 ° C. The stretching temperature is selected on the basis of the glass transition temperature of the fiber, but is usually preferably about 15 to 80 ° C. More preferably, it is 25-70 degreeC. The draw ratio is preferably 3 to 20 times in the length direction of the fiber, more preferably 3 to 10 times. The drawn fiber is preferably subjected to annealing and heat treatment in order to make the properties of tensile strength and dimensional stability uniform. The annealing is preferably performed for about 0.01 to 30 seconds at a temperature of 0.5 to 10% or under tension, preferably at 40 to 130 ° C. The heat treatment is preferably performed after annealing for 1 to 72 hours under tension under a reduced pressure of 40 to 150 ° C. and 130 to 100,000 Pa.
In order to obtain particularly high orientation, gel spinning method, liquid crystal spinning method, vibrational thermal stretching method, dielectric heating stretching method, two-stage stretching method (solid phase coextrusion, tensile stretching), stretching under pressure, zone heat treatment A method such as a method can be used.
The resin of the present invention thus obtained can be further processed by cutting, polishing or the like as required.
[0035]
[Other additives]
Other additives than the above-mentioned additives can be added to the polylactic acid resin used in the present invention according to the purpose.
Specific examples of additives include, for example, plasticizers, heat stabilizers, light stabilizers, antioxidants, ultraviolet absorbers, pigments, colorants, various fillers, antistatic agents, mold release agents, fragrances, lubricants, difficulty Examples include a flame retardant, a foaming agent, a filler, an antibacterial agent, an antibacterial agent, and a nucleation agent.
[0036]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited only to an Example.
[0037]
[Production Example 1]
100 parts by weight of L-lactide, 0.01 part by weight of stannous octoate, and 0.03 part by weight of lauryl alcohol were charged into a thick cylindrical stainless steel polymerization vessel equipped with a stirrer, and were vacuumed for 2 hours. After degassing, it was replaced with nitrogen gas. The mixture was heated at 200 ° C. for 3 hours with stirring under a nitrogen atmosphere. While maintaining the temperature as it is, the inside of the reaction vessel was gradually depressurized to 3 mmHg by gradually deaeration with a vacuum pump through an exhaust pipe and a glass receiver. One hour after the start of degassing, the monomer and low molecular weight volatile components were no longer distilled, so the interior of the container was purged with nitrogen, and the polymer was extracted in the form of a strand from the bottom of the container and pelletized to obtain polylactic acid. The weight average molecular weight Mw was 130,000.
[0038]
[Production Example 2]
To a 1 liter reactor equipped with a Dien-Stark trap, 100 g of 90% L-lactic acid was distilled off at 150 ° C. and 50 mmHg for 3 hours while stirring for 3 hours, and then 0.062 g of tin powder was added. The mixture was further oligomerized by stirring at 30 mmHg for 2 hours. To this oligomer, 0.288 g of tin powder and 211 g of diphenyl ether were added, and azeotropic dehydration was performed at 150 ° C. and 35 mmHg. The distilled water and the solvent were separated by a water separator, and only the solvent was returned to the reactor. After 2 hours, the solvent to be returned to the reactor was passed through a column packed with 460 g of molecular sieves 3A and then returned to the reactor, and reacted at 150 ° C. and 35 mmHg for 40 hours to obtain a polylactic acid solution. 440 g of dehydrated diphenyl ether was added to this solution, diluted and then cooled to 40 ° C., and the precipitated crystals were filtered, washed 3 times with 100 g of n-hexane, and dried at 60 ° C. and 50 mmHg. This powder was added with 120 g of 0.5N hydrochloric acid and 120 g of ethanol, stirred at 35 ° C. for 1 hour, filtered, and dried at 60 ° C. and 50 mmHg to obtain polylactic acid. The weight average molecular weight Mw of this polylactic acid was 145,000.
[0039]
[Example 1]
5 parts of cholesteryl bromide was mixed with 95 parts by weight of the polylactic acid obtained in Production Example 1, and melt extruded at 240 ° C. and spun using an extruder. The obtained fiber was stretched 5 times in the length direction at 50 ° C., and then annealed under tension at 60 ° C. for several seconds, and further heat-treated at 110 ° C. under reduced pressure for 3 hours.
When the optical rotation of this fiber was measured, it was 100 ° / 1 mm and had flexibility.
[0040]
[Example 2]
5 parts of cholesteryl bromide was mixed with 95 parts by weight of the polylactic acid obtained in Production Example 2, and fibers were obtained in the same manner as in Example 1.
When the optical rotation of this fiber was measured, it was 87 ° / 1 mm and had flexibility.
[0041]
[Comparative Example 1]
When the optical rotation of quartz (α-SiO 2) was measured, it was 25 ° / 1 mm and there was no flexibility.
[0042]
【The invention's effect】
Light optical element obtained from the composition and the composition of the present invention, moldability, processability, flexibility, light weight, thin film properties, excellent in handling property, can be widely used in various fields.

Claims (13)

A polylactic acid resin, from 0.001 to 30 composition characterized in that it comprises by weight% as an additive a cholesteric liquid crystal compound on the weight of the polylactic acid resin as a reference. The composition according to claim 1, wherein the polylactic acid resin is polylactic acid . The composition according to claim 1 or 2, wherein the isomer content in the lactic acid-derived repeating unit in the polylactic acid-based resin is 0 to 10 mol% . 4. The composition according to claim 1, wherein the cholesteric liquid crystal compound is a halogen compound of cholesterol. The composition according to any one of claims 1 to 4, which has an optical rotation . The composition according to claim 5, which has optical rotation in at least two axial directions . An optical element obtained from the composition according to claim 1. 8. The optical element according to claim 7, wherein the optical element is a light modulation element. The optical element according to claim 8 , wherein a driving frequency of light modulation is 1 MHz to 100 GHz. The optical element according to claim 8 or 9 , wherein a drive voltage for light modulation is 0.01 kV / m to 1 MV / m . Optical element having the shape of fibers according to either one described in claims 7 to 10. Optical element having a shape of a film according to either one described in claims 7 to 10. Optical element is a molded article wherein the ratio of length to thickness described is 3 to 1 or more to any one of claims 7 to 10.