JP2005146169A - Resin composition with low refractive index and optical molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition with low refractive index, which has no birefringence and is excellent in transparency and stability, and also to provide an optical molded product prepared by molding the above resin composition. <P>SOLUTION: The resin composition with low refractive index is prepared by dispersing in a transparent resin an inorganic-organic composite material obtained by having an inorganic laminar compound supported with an organic low molecular compound. The above inorganic-organic composite material and the above transparent resin exhibit each an orientation birefringence with a sign opposite to each other. The optical molded product is prepared by molding the above resin composition. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  In the present invention, an inorganic / organic composite obtained by supporting an organic low molecular weight compound on an inorganic layered compound is dispersed in a transparent resin, and the inorganic / organic composite and the transparent resin have opposite signs. The present invention relates to a low birefringence resin composition characterized by exhibiting an orientation birefringence, and an optical molded body formed by molding this resin composition.

  In recent years, materials such as spectacle lenses and other optical parts, optical parts for optoelectronics, and liquid crystal displays have been developed because of their superior characteristics such as lightness, impact resistance, and moldability compared to conventional glass-based materials. Optical resin materials are used as various members constituting the liquid crystal element, which is the main constituent element.

  However, in reality, optical components obtained from optical resin materials exhibit birefringence due to the inevitable orientation of resin molecules that occur during molding, and this birefringence impairs the functionality of optical components. Therefore, development of an optical resin material having no birefringence is demanded.

  In order to meet such a demand, Patent Document 1 discloses a non-compound that is formed by forming a transparent matrix with a polymer resin and adding a low-molecular substance having an orientation birefringence opposite to that of the polymer resin. A refractive optical resin material is disclosed. However, in this method, since the orientation of the low molecular weight substance to be added is not controlled, the optical characteristics may vary. Moreover, since a large amount of low molecular weight substances are added, the heat resistance of the resulting resin material is lowered.

  In Patent Document 2, a transparent polymer resin and a fine chain having birefringence that is aligned in the same direction as the alignment direction of the bond chain as the bond chain of the polymer resin is aligned by an external force. An optical resin material containing an inorganic substance and canceling out the orientation birefringence in the oriented polymer resin by the birefringence of the inorganic substance is described.

  When the inorganic substance is dispersed in the resin as described above, in order to obtain sufficient transparency as an optical material, the particle diameter of the inorganic substance should be several tens of nm or less, and the particles should be uniformly dispersed so as not to aggregate. It is necessary to let However, in practice, it has been difficult to obtain a highly transparent composition by carrying out such a high degree of dispersion.

JP-A-8-110402 WO01 / 25364

  The present invention has been made in view of the situation of the prior art, and has a low birefringence resin composition having a small birefringence and excellent in transparency and stability of other optical properties, and molding the resin composition. It is an object to provide an optical molded body.

  As a result of intensive studies to solve the above problems, the present inventors have obtained an inorganic / organic composite in which a specific organic low molecular weight compound is supported on a layered silicate, and this inorganic / organic composite has an orientation birefringence. When dispersed in a resin opposite to the composite, it is possible to obtain a resin composition having low birefringence and excellent transparency and stability, and the obtained resin composition is an optical molded body. The inventors have found that it can be suitably used as a raw material, and have completed the present invention.

  Thus, according to the first aspect of the present invention, an inorganic / organic composite obtained by loading an inorganic layered compound with an organic low molecular weight compound is dispersed in a transparent resin, and the inorganic / organic composite and the transparent Provided is a low birefringence resin composition characterized by exhibiting an orientation birefringence having a sign opposite to that of a resin.

In the low birefringence resin composition of the present invention, the inorganic layered compound is more preferably a layered silicate.
In the low birefringence resin composition of the present invention, the transparent resin is preferably an alicyclic structure-containing polymer resin.
According to the second aspect of the present invention, there is provided an optical molded body obtained by molding the low birefringence resin composition of the present invention.

According to the present invention, there is provided a resin composition that is easy to produce, has a small birefringence, has sufficient transparency, and is excellent in other optical characteristics.
The resin composition of the present invention is obtained by dispersing an inorganic / organic composite in a resin. This inorganic / organic composite has excellent dispersibility in the resin, so even if it is added in a large amount to reduce birefringence, it can be dispersed uniformly, and has excellent transparency and low birefringence. And other optical properties can be obtained.
The resin composition of the present invention is suitable as an optical material for producing optical molded articles such as optical lenses and optical films.

1) Resin Composition The low birefringence resin composition of the present invention is characterized in that an inorganic / organic composite obtained by supporting an organic low molecular weight compound on an inorganic layered compound is dispersed in a transparent resin. To do.

(1) Resin The transparent resin used in the present invention is not particularly limited as long as it is excellent in transparency. Examples of positive signs of orientation birefringence include, for example, alicyclic structure-containing polymers, chain olefin polymers such as polyethylene and polypropylene, triacetyl cellulose, polyvinyl alcohol, polyimide, polyarylate, polyester, polycarbonate, Polysulfone, polyethersulfone and the like can be mentioned.

Examples of the negative sign of the orientation birefringence include polystyrene and polymethyl methacrylate. Among these, an alicyclic structure-containing polymer is preferable from the viewpoints of transparency, low hygroscopicity, dimensional stability, lightness, and the like.

  The alicyclic structure-containing polymer is a polymer containing an alicyclic structure in the repeating unit of the polymer. Examples of the alicyclic structure include a cycloalkane structure and a cycloalkene structure. From the viewpoint of thermal stability of a resin composition or a molded product obtained from the composition, a cycloalkane structure is preferable.

  Carbon number which forms an alicyclic structure is 4-30 normally, Preferably, it is 5-20, More preferably, it is 5-15. When the carbon number is in this range, a molded product obtained from a resin composition having excellent heat resistance and flexibility or this alicyclic structure-containing polymer composition is obtained. This alicyclic structure may be present in either the main chain or the side chain of the polymer.

  The content ratio of the repeating unit containing the alicyclic structure in the alicyclic structure-containing polymer is not limited, and is appropriately selected according to the properties, physical properties, and the like of the resin composition to be obtained. Preferably it is 70 mass% or more, More preferably, it is 90 mass% or more. When the content ratio of this repeating unit is too small, the heat resistance of the resulting resin composition may be lowered, which is not desirable.

  Examples of the alicyclic structure-containing polymer used in this invention include a norbornene polymer (A), a monocyclic olefin polymer (B), a cyclic conjugated diene polymer (C), and a vinyl alicyclic hydrocarbon heavy polymer. A combination (D) and a mixture thereof can be exemplified. Among these polymers, from the viewpoint of heat resistance and mechanical strength of the resulting alicyclic structure-containing polymer composition, hydrides of norbornene polymers, vinyl alicyclic hydrocarbon polymers, and vinyl alicyclic carbonizations. Hydrogenated hydrides are preferred.

  Examples of the norbornene polymer (A) include a ring-opening polymer of a norbornene-based monomer, a ring-opening copolymer of a norbornene-based monomer and another monomer capable of ring-opening copolymerization with this monomer, and a hydride of these polymers. And addition polymers of norbornene monomers and addition copolymers of norbornene monomers and other monomers copolymerizable with the monomers. Among these polymers and copolymers, a hydride of a ring-opening polymer of a norbornene monomer is particularly preferable from the viewpoint of heat resistance and mechanical strength of the resulting alicyclic structure-containing polymer composition.

Examples of the norbornene-based monomer include bicyclo [2.2.1] -hept-2-ene (common name: norbornene) and derivatives thereof (having substituents in the ring, the same shall apply hereinafter), tricyclo [4.3. .0.1 ^2,5 ] deca-3,7-diene (common name: dicyclopentadiene) and derivatives thereof, 7,8-benzotricyclo [4.3.0.1 ^2,5 ] dec-3- Ene (common name: metatetrahydrofluorene) and its derivatives, tetracyclo [4.4.0.1 ^2,5 . ^{17, 10} ] dodec-3-ene (common name: tetracyclododecene) and its derivatives.

  Examples of the substituent include an alkyl group, an alkylene group, a vinyl group, and an alkoxycarbonyl group. The norbornene-based monomer may have one or more of these substituents. Also good.

As the norbornene-based monomer having these substituents, 8-methyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-ethyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-methylidene-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-ethylidene-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-methoxycarbonyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-methyl-8-methoxycarbonyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene and the like. These norbornene monomers can be used alone or in combination of two or more.

  The ring-opening polymer of the norbornene-based monomer or the ring-opening copolymer of the norbornene-based monomer and another monomer capable of ring-opening copolymerization with this monomer polymerizes the monomer in the presence of a known ring-opening polymerization catalyst. Can be manufactured. Examples of other monomers capable of ring-opening copolymerization with the norbornene monomer include monocyclic olefin monomers such as cyclohexene, cycloheptene, and cyclooctene.

  A hydride of a ring-opening polymer of the norbornene-based monomer or a hydride of a ring-opening copolymer of a norbornene-based monomer and another monomer capable of ring-opening copolymerization with this monomer is usually the ring-opening polymer or It can manufacture by adding the well-known hydrogenation catalyst containing transition metals, such as nickel and palladium, to the polymerization liquid containing a ring-opening copolymer, and hydrogenating a carbon-carbon unsaturated bond.

  The addition polymer of the norbornene monomer or the addition copolymer of the norbornene monomer and another monomer copolymerizable with the monomer is produced by polymerizing the monomer in the presence of a known addition polymerization catalyst. Can do.

  Examples of other monomers capable of addition copolymerization with norbornene-based monomers include α-olefins having 2 to 20 carbon atoms such as ethylene, propylene, 1-butene, and derivatives thereof; cyclobutene, cyclopentene, 3a, 5,6,7a- Examples thereof include cycloolefins such as tetrahydro-4,7-methano-1H-indene and derivatives thereof; non-conjugated dienes such as 1,4-hexadiene and 4-methyl-1,4-hexadiene. Among these monomers, α-olefins, particularly ethylene is preferable. Other monomers capable of addition copolymerization with the norbornene monomer may be used alone or in combination of two or more.

  In addition copolymerization of a norbornene monomer and another monomer that can be addition copolymerized with this monomer, the structural unit derived from the norbornene monomer in the resulting copolymer, and another copolymerizable monomer The amount of each monomer used is selected so that the ratio of the structural unit derived from is usually 50:50 to 99: 1, preferably 70:30 to 95: 5 in terms of mass ratio.

  Examples of the monocyclic olefin polymer (B) include addition polymers of monocyclic olefin monomers such as cyclohexene, cycloheptene, and cyclooctene, and hydrides thereof.

  Examples of the cyclic conjugated diene polymer (C) include 1,2- or 1,4-addition polymers of cyclic conjugated diene monomers such as cyclopentadiene and cyclohexadiene, and hydrides thereof.

  Examples of the vinyl alicyclic hydrocarbon polymer (D) include polymers of vinyl alicyclic hydrocarbon monomers such as vinylcyclohexene and vinylcyclohexane, and hydrides thereof, and vinyl aromatics such as styrene and α-methylstyrene. Hydrides obtained by hydrogenating aromatic moieties contained in polymers of aromatic hydrocarbon monomers, vinyl alicyclic hydrocarbon monomers or vinyl aromatic hydrocarbon monomers and other monomers copolymerizable with these monomers And a random copolymer, a copolymer such as a block copolymer, and a hydride thereof. Examples of the block copolymer include diblock, triblock or more multiblock, and gradient block copolymer.

  In the present invention, since the affinity with the inorganic layered compound can be improved and the heat resistance can be improved without impairing the light transmittance of the optical film obtained from the resin composition, the alicyclic ring used The structure-containing polymer preferably has a polar group.

  Examples of the polar group include heteroatoms or atomic groups having heteroatoms. Examples of the heteroatoms include oxygen atoms, nitrogen atoms, silicon atoms, and halogen atoms. Among these heteroatoms, an oxygen atom and a nitrogen atom are preferable from the viewpoints of dispersibility and compatibility with the layered compound. Specific examples of the polar group include a carboxyl group, a carbonyloxycarbonyl group, an epoxy group, a hydroxy group, an oxy group, an ester group, a silanol group, a silyl group, an amino group, a nitrile group, and a sulfone group.

  The method for obtaining the alicyclic structure-containing polymer having a polar group is not particularly limited, but when the alicyclic structure-containing polymer is a norbornene polymer, for example, (1) selected from various norbornene monomers A method of reacting (modifying) a compound having a polar group with an unmodified polymer obtained by polymerizing a norbornene-based monomer having no polar group, and (2) from among various norbornene-based monomers A method of copolymerizing a selected norbornene monomer having no polar group and a norbornene monomer having a polar group; and (3) a polar group having a polar group selected from various norbornene monomers. A polymer obtained by polymerizing a norbornene-based monomer which is not subjected to the polymerization, and a nor group having a polar group obtained by the method (1) or (2) It can be mentioned a method of mixing the Runen polymer. The alicyclic structure-containing polymer other than the norbornene polymer is the same as that of the norbornene polymer.

  Examples of the alicyclic structure-containing polymer having a polar group include chlorinated products of alicyclic structure-containing polymers, chlorosulfonated products, and graft modified products of polar group-containing unsaturated compounds. A graft modified product with a polar group-containing unsaturated compound is preferred.

  Examples of the polar group-containing unsaturated compound include unsaturated epoxy compounds such as glycidyl acrylate, glycidyl methacrylate, glycidyl p-styrylcarboxylate, allyl glycidyl ether, and glycidyl ether of 2-methylallyl glycidyl ether; acrylic acid and methacrylic acid , Α-ethylacrylic acid, maleic acid, fumaric acid, itaconic acid, etc .; unsaturated carboxylic acid compounds; maleic anhydride, chloromaleic anhydride, butenyl succinic anhydride, etc .; monomethyl maleate, maleic acid Unsaturated ester compounds such as dimethyl and glycidyl malate; unsaturated alcoholic compounds such as allyl alcohol, 2-allyl-6-methoxyphenol and 4-allyloxy-2-hydroxybenzophenone; chlorodimethyl Nirushiran, trimethylsilylacetylene, 5-trimethylsilyl-1,3-cyclopentadiene, 3-trimethylsilylallyl alcohol, and the like unsaturated silane compounds, such as trimethylsilyl meth click relay Bok.

  Among these polar group-containing unsaturated compounds, unsaturated epoxy compounds and unsaturated carboxylic acid compounds are particularly preferable from the viewpoint of uniformly dispersing the inorganic layered compound. In order to efficiently modify the alicyclic structure-containing polymer with the polar group-containing unsaturated compound, it is preferable to carry out the reaction in the presence of a general-purpose radical initiator, and as this suitable radical initiator, Organic peroxide, organic perester, etc. are mentioned.

  The alicyclic structure-containing polymer having a polar group preferably has a polar group amount of 0.01 mmol / g or more, more preferably 0.01 to 0.8 mmol / g. What is 01-0.5 mmol / g is still more preferable. When the amount of the polar group is within the above range, the affinity with the layered compound can be further improved.

  The amount of the polar group depends on the introduction rate of the polar group by the reaction of the compound having a polar group in the method (1), and depends on the copolymerization ratio of the monomer having a polar group in the method (2). In the method (3), it can be adjusted by the mixing ratio of the polymer having no polar group and the polymer having a polar group.

  Although there is no restriction | limiting in particular in the molecular weight of resin used for this invention, The weight average molecular weight of polystyrene conversion is 5,000-500,000 normally, Preferably, 8,000-200,000, More preferably, it is 10,000. 000-100,000. When the weight average molecular weight is in this range, the molding processability of the resulting resin composition is improved, and the mechanical strength of the molded body can be improved. This weight average molecular weight can be measured by gel permeation chromatography (GPC) of a cyclohexane solution or a toluene solution.

  Although there is no restriction | limiting in particular also in the glass transition temperature (Tg) of resin used for this invention, Usually, 80 degreeC or more, Preferably it is 130-250 degreeC. When the glass transition temperature is in this range, it is possible to obtain a resin composition that can withstand use at high temperatures and does not cause thermal deformation, stress concentration, or the like, and provides a molded article having excellent durability.

(2) Inorganic / organic composite In the present invention, the inorganic / organic composite dispersed in the transparent resin is a particle having a layered (nano-sized sheet) shape. For this reason, when orientation distortion is applied to the molded body made of the resin composition of the present invention by stretching or the like, the axis and the resin are formed when an arbitrary direction in the plane of the inorganic / organic composite is taken as the axis (x-axis). Molecular chains are oriented in the same direction. At that time, the thickness direction (z-axis) of the surface is in the plane with the x-axis as a normal line, but the direction is arbitrary, and it is considered that a large number of particles are statistically uniformly distributed. Accordingly, regarding the orientation birefringence of the inorganic / organic composite of the present invention, a rotating body symmetric about the x-axis is considered, and the direction of the symmetric axis (x-axis) and the direction perpendicular to it (y-axis and z-axis) What is necessary is to consider the refractive index difference.

In the present invention, an organic low molecular weight compound is supported on the surface of the inorganic layered compound.
In the present invention, the term “support” refers to a bond between the inorganic layered compound and the organic low molecular weight compound that has sufficient strength to cause the orientation of the organic low molecular weight compound and sufficient stability under actual use conditions. That is formed. Examples of the bond include a physical bond and a scientific bond, but a chemical bond such as a covalent bond, an ionic bond, a hydrogen bond, and a coordination bond is preferable from the viewpoint of bond strength and stability.

The orientation here is an orientation in a plane direction of the inorganic layered compound, a normal direction of the plane, or a direction having a certain inclination from the normal direction of the plane. In the present invention, this orientation direction is not limited and can be selected according to the purpose.

  In the present invention, it is not necessarily essential for the present invention to confirm that the organic compound is supported on the inorganic layered compound, but if necessary, for example, a chemical bond generated by the reaction may be subjected to a nuclear magnetic resonance spectrum ( NMR spectrum).

(3) Inorganic layered compound The inorganic layered compound used in the present invention is in a state (layered) having a structure in which the compound is planarly arranged, and has a polycrystalline layer structure having a repeated planar structure in the vertical direction. A compound. In this layered compound, the crystal layers are bonded to each other by van der Waals force or hydrogen bond force, and the cation is interposed between the crystal layers, and the negatively charged crystal layers are mutually connected to the positive electrode. It can be roughly classified into those coupled by a weak electrostatic force through ions.

Examples of the layered compound described above include graphite; transition metal dichalcogenides such as TiS ₂ , NbSe ₂ , and MoS ₂ ; divalent metal phosphorus chalcogenides such as CrPS ₄ ; oxidation of transition metals such as MoO ₃ and V ₂ O _5. Oxyhalides such as FeOCl, VOCl, CrOCl; hydroxides such as Zn (OH) ₂ and Cu (OH) ₂ ; Zr (HPO ₄ ) ₂ .nH ₂ O, Ti (HPO ₄ ) ₃ .nH ₂ Phosphate salts such as O, Na (UO ₂ PO ₄ ) ₃ .nH ₂ O; Titanates such as Na ₂ Ti ₃ O ₇ , KTiNbO ₅ , RbxMnxTi _2-x O ₄ ; Na ₂ U ₂ O ₇ , K Uranates such as ₂ U ₂ O ₇ ; KV ₃ O ₈ , K ₃ V ₅ O ₁₄ , CaV ₆ O ₁₆ .nH ₂ O, Na (UO ₂ V ₃ O ₉ ) .nH ₂ O Vanadates such as: Niobates such as KNb ₃ O ₃ and K ₄ Nb ₆ O ₁₇ ; Tungstates such as Na ₂ W ₄ O ₁₃ and Ag ₄ W ₁₀ O ₁₃ ; Mg ₂ Mo ₂ O ₇ · Cs _{2 Mo 5 O 16, Cs 2} Mo 7 O 22, Ag 4 Mo 10 molybdates such as _{O 33;} montmorillonite, saponite, Heide light, hectorite, nontronite, stevensite emission site, trioctahedral vermiculite, di oct polyhedral vermiculite, muscovite, Fi logo bytes, biotite, lepidolite, Baragonaito, tetrasilicic chromite, kaolinite, halloysite, _dickite, such as _{H 2 SiO 5, H 2 Si} 14 O 29 · 5H 2 O, silicate Examples include salts or minerals composed of this silicate. Rukoto can.
Among these, layered silicates are particularly preferable from the viewpoints of dispersibility in the resin, heat resistance of the resulting resin composition, and mechanical strength.

  The layered compound used in the present invention preferably has a length of 500 nm or less, more preferably has a length of 10 to 500 nm, and still more preferably has a length of 10 to 200 nm. Here, the length means the length (D1) in the major axis direction, and when the layered compound dispersed in the resin is viewed, it means that the longest D1 in the dispersed layered compound is 500 nm. doing. In the present invention, since the layered compound having a major axis length (D1) of 500 nm or less is used, light scattering is prevented when the layered compound is dispersed in the resin, and the transparency is improved. An excellent resin composition molded body can be obtained.

  If the inorganic layered compound has a long axis length (D1) that is too long, light scattering occurs when dispersed in the resin, and the resulting resin composition tends to have poor transparency. There is a tendency that the orientation in the composition is deteriorated and the effect of low birefringence is inferior.

  In the present invention, the inorganic layered compound is used after being cleaved into a sheet having a thickness of 30 nm or less, preferably 20 nm or less, more preferably 10 nm or less and dispersed in the resin. The most preferable state of cleaving / dispersing is a uniform dispersion without aggregation in the resin as a single layer nanosheet.

  In order to improve the cleavage and dispersibility in the resin, it is preferable to perform an organophilic treatment on the inorganic layered compound. The organophilic treatment refers to a treatment in which organic molecules are introduced between the layers of the inorganic layered compound to organically modify the unit layer surface.

When the cation exchangeable inorganic layered compound is used, the organophilic treatment is usually performed by replacing metal ions between layers of the inorganic layered compound with organic onium ions. Examples of the compound having an organic onium ion group include a compound having a quaternary ammonium salt, a pyridinium group, a sulfonium group, a phosphonium group, etc. in the molecule, and generally a compound having a quaternary ammonium group, formula ^{R l R 2 R 3 R 4} N + X - quaternary ammonium salt represented by is used.

In R ¹ R ² R ³ R ⁴ N ⁺ X ⁻ , R ¹ , R ² , R ³ and R ⁴ each independently represents a saturated or unsaturated hydrocarbon group having 1 to 30 carbon atoms. Examples of the saturated or unsaturated hydrocarbon group having 1 to 30 carbon atoms include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, 21-ethylhexyl group, heptyl group, octyl group, nonyl group, decyl group. A saturated aliphatic hydrocarbon group such as a group, dodecyl group, hexadecyl group or octadecyl group; an unsaturated aliphatic hydrocarbon group such as a lauryl group or an oleyl group; an aromatic hydrocarbon group such as a phenyl group or a benzyl group. it can. Examples of X include Cr, Br, NO ₃ , OH, and CH ₃ COO.

  The organic layering treatment of the inorganic layered compound is, for example, preparing an inorganic layered compound dispersion by swelling and dispersing the inorganic layered compound in water, adding the compound having the organic onium ion group to this dispersion, It can carry out by stirring under heating. The inorganic layered compound that has been subjected to the organophilic treatment is preferably used after it is washed well with water to remove water-soluble impurities such as inorganic salts and well dried.

(4) Organic low molecular compound The organic low molecular compound used in the present invention is not particularly limited as long as it is a compound that can be supported on an inorganic layered compound, but a part of the molecule has a rod-like structural unit having a high polarizability. It is preferable that they are arranged.

  Examples of the rod-like structural unit having a high polarizability include biphenyl, naphthalene, anthracene, phenanthrene, fluorene, phenylcyclohexane, diphenyl ether, diphenyl sulfide, stilbene, diphenylacetylene, benzoin, benzylbenzoate, azomethine, and azobenzene. These structural units may be further linked or combined.

  In addition to the above structure, the organic low molecular compound used in the present invention preferably has a polar group in the molecule for generating a chemical bond or a physical bond with the surface of the inorganic layered compound. . Examples of the polar group include a functional group containing a hetero atom such as an oxygen atom or a nitrogen atom. Specifically, a hydroxyl group, a carbonyl group, a carboxyl group, an ester group, a sulfonyl group, an amide group, an amino group, a cyano group, A quaternary ammonium group, a pyridinium group, a sulfonium group, a phosphonium group, a trialkoxyl group, and the like can be given.

  The position and number of polar groups in the organic low-molecular compound are selected according to the purpose. For example, when one end of the rod-like molecular structure has a polar group, the rod-like molecular structure is often supported in a state of being oriented substantially perpendicular to the surface of the inorganic layered compound. In many cases, a rod-like molecular structure is supported in a state of being oriented in a substantially horizontal direction with respect to the surface of the inorganic layered compound. For example, when the rod-like molecular structure is supported in a state of being oriented in a direction perpendicular to the plane of the inorganic layered compound, the resulting inorganic / organic composite has a refractive index anisotropic body having a refractive index greater in the thickness direction than that plane. can do.

  The organic low molecular weight compound used in the present invention has a molecular weight of 500 or less, preferably 400 or less, more preferably 300 or less. When the molecular weight is excessively large, the supporting rate on the inorganic layered compound may be deteriorated, or the stability of the alignment state may be deteriorated.

  A method for obtaining an inorganic / organic composite by supporting an organic low molecular weight compound on an inorganic layered compound is not particularly limited. For example, a dispersion obtained by swelling and dispersing the organic layered inorganic layered compound in an organic solvent is used. It can be prepared by adding an organic low molecular weight compound to this dispersion and stirring at room temperature or under heating.

  The organic solvent used here is not particularly limited, and examples thereof include aromatic hydrocarbons such as benzene, toluene and xylene; chain and cyclic aliphatic hydrocarbons such as heptane and cyclohexane; chlorobenzene, dichlorobenzene, Halogenated hydrocarbons such as trichlorobenzene and dichloromethane; ethers such as dioxane and diethyl ether; ketones such as acetone, cyclohexanone, methyl ethyl ketone and acetophenone; esters such as ethyl acetate and propiolactone; nitriles such as acetonitrile and benzonitrile Alcohols such as methanol, ethanol, propanol, butanol, ethylene glycol, diethylene glycol; other water, nitrobenzene, sulfolane, dimethylformamide, And the like methyl sulfoxide. These may be used alone or in combination of two or more. Aromatic hydrocarbons, halogenated hydrocarbons, alcohols, and water are preferred, with xylene, toluene, dichlorobenzene, and trichlorobenzene being particularly preferred.

  The amount of the organic solvent used is in the range of 1: 0 to 1: 100 of the organic layered inorganic layered compound: solvent by weight ratio. If the amount of the solvent used is too small, the dispersion becomes highly viscous and difficult to handle, and if it is too large, the solvent removal efficiency in the subsequent process may be deteriorated. Is preferably in the range of 1: 4 to 1:60.

The method of swelling and dispersing the inorganic layered compound in an organic solvent is not particularly limited,
Various methods can be used. For example, a method of mixing both using a stirring tank, a method of mixing both using a blender, a method of mixing both using a high speed mixer such as a Henschel mixer, and the like can be taken. Moreover, it is preferable to mix while applying ultrasonic waves at this time in order to increase the degree of swelling and make the dispersion of the inorganic layered compound uniform.

The obtained inorganic / organic composite may be used in the form of a dispersion dispersed in a solvent, or may be used in the form of a powder from which the solvent has been removed and dried.
In addition to this, when carrying out the organophilicity, it may be carried out by a method using the compound having the rod-like molecular structure as an organophilic agent.

(5) Production of Resin Composition The resin composition of the present invention includes, for example, (i) a method of blending a resin and an inorganic / organic complex in a solution and then removing the solvent, and (ii) a resin and an inorganic / organic composite. The organic composite can be produced by a melt kneading method using a single screw extruder, a twin screw extruder, a roll, a Banbury mixer, a kneader, or the like. You may use the method of performing melt kneading after the method of (i), and the method of performing solvent removal and melt kneading simultaneously by the method of (i). In the point that the dispersibility of the inorganic / organic composite in the resin can be improved, melt kneading is performed simultaneously with the removal of the solvent by the method (i) or the method (i), or subsequent to the solvent removal. The method is preferred.

  In the method (i), an inorganic / organic composite in a dispersion state swollen and dispersed in an organic solvent is used. As the organic solvent used here, the same organic solvent as that used in the method for obtaining the inorganic / organic composite by supporting the organic low molecular weight compound on the inorganic layered compound can be used. The same applies to the method of swelling and dispersing the inorganic / organic composite in an organic solvent. Further, as described above, after preparing the inorganic / organic composite, it may be used as it is in the state of dispersion without removing the solvent.

  The inorganic / organic composite dispersion is mixed with a separately prepared resin solution, or the resin is added directly to the inorganic / organic composite dispersion to dissolve and mix to obtain a mixed solution. When preparing a resin solution separately, it is preferable to use the same solvent as the solvent used to prepare the inorganic / organic composite dispersion, but it is also possible to use a different solvent. The mixing method is not particularly limited, and various methods can be used.

  Thus, the method for removing the solvent after preparing the mixture is not particularly limited, but a method using a solvent removing apparatus capable of heating and depressurizing is preferable, and in particular, the solution can be continuously heated and depressurized in a thin film state. It is preferable to use a thin film type solvent removing apparatus at a temperature of 100 ° C. to 350 ° C. and a pressure of 10 kPa or less.

  The resin composition from which the solvent has been removed is preferably further melt-kneaded using a twin screw extruder or the like. In that case, the molten resin composition discharged from the continuous thin film solvent removing apparatus is used as it is as the twin screw extruder. It is also possible to carry out melt kneading continuously by supplying to the kneading zone.

(6) Resin Composition The resin composition of the present invention is obtained by dispersing an inorganic / organic composite obtained by supporting an organic low molecular weight compound in an inorganic layered compound in a transparent resin, The organic composite and the transparent resin exhibit orientation birefringence with opposite signs.

  Here, the orientation birefringence refers to birefringence caused by the difference between the refractive index in the orientation direction of the resin molecular chain and the refractive index in the direction perpendicular thereto due to stretching of the resin molded body and flow during molding. When the refractive index in the orientation direction is larger than the refractive index in the direction perpendicular to it, it is said to have positive orientation birefringence, and conversely, the refractive index in the orientation direction is smaller than the refractive index in the direction perpendicular to it. In some cases, it has negative orientation birefringence.

The resin composition of the present invention is particularly excellent in transparency, and is suitable as an optical material as described later.
When the resin composition of the present invention is formed into a molded body, the haze value at an optical path length of 1 mm is preferably 5% or less, more preferably 1% or less, and particularly preferably 0.5% or less. The haze value (%) is expressed as a percentage of transmitted light that is measured by the forward scattering and deviated by 0.04 rad (2.5 degrees) or more from the incident light, in accordance with JIS K7136. When a resin composition having a haze of 5% or less at an optical path length of 1 mm when formed into a molded product is used in an optical product, uniform brightness with little scattered light can be ensured.

  When the resin composition of the present invention is molded, the total light transmittance at an optical path length of 1 mm is preferably 85% or more, more preferably 90% or more, and particularly preferably 91% or more. The total light transmittance is measured in accordance with JIS K7361, and is represented by the ratio of the total transmitted light to the incident light beam on the flat test piece having a thickness of 1 mm. A resin composition having a total light transmittance of 90% or more when formed into a film is suitable as an optical material.

  The resin composition of the present invention can be molded by a method according to the application, such as an injection molding method, a press molding method, or a cast molding method, utilizing its thermoplasticity. Further, it is possible to form a film from a solution by utilizing the solvent solubility.

2) Optical molded body The optical molded body of the present invention is formed by molding the resin composition of the present invention. The shape of the optical molded body of the present invention is not particularly limited, and may be a shape and size according to various purposes. A molding method is not particularly limited, and a known molding method can be employed. Examples thereof include an injection molding method, an injection compression molding method, a press molding method, an extrusion molding method, a blow molding method, and a vacuum molding method. In the case of forming into a film, an extrusion molding method using a T-die, a calendar molding method, an inflation molding method, or a solution casting method can also be used.

  The optical molded body of the present invention has characteristics such as excellent transparency, low birefringence, low water absorption, and light weight, and thus, for example, an optical information recording medium substrate, a camera or a camera or a portable information device with a camera. Lenses, Fθ lenses for laser beam printers, optical lenses such as pickup lenses for optical information recording devices, substrates for flat panel display elements such as eyeglass lenses, liquid crystal display devices, EL display devices, polarizing plate protective films, It can be suitably used as an optical film such as a touch panel substrate, a light guide plate and the like.

  The optical film obtained from the resin composition of the present invention is used as a member of an optical device such as a liquid crystal display device, an organic EL element, a plasma display, or a projector. Specifically, an IR cut filter, a retardation film, a polarizing plate protective film, a film for a liquid crystal cell substrate, a liquid crystal display element substrate, a touch panel substrate, or a raw film thereof can be used. These films may be used by laminating an antireflection film, an antiglare film, a hard coat layer, an antifouling layer, a transparent conductive film or the like as a post process by a dry method or a wet method.

  The present invention will be described in more detail with reference to production examples, examples and comparative examples, but the present invention is not limited to the following examples. Parts and% are based on weight unless otherwise specified.

Evaluation in this example was performed by the following method.
(1) Molecular weight of polymer: Measured by gel permeation chromatography (GPC) using cyclohexane as a solvent, and a weight average molecular weight (Mw) in terms of standard polystyrene or polyisoprene was determined.
(2) Total light transmittance, haze: Total light transmittance was measured according to JIS K7361, and haze was measured according to JIS K7136.
(3) Retardation, three-dimensional refractive index; measured by KOBRA-21ADH manufactured by Oji Scientific Instruments.
(4) Dispersion state of the inorganic layered compound in the resin composition; observed with a transmission electron microscope (manufactured by Hitachi, Ltd., magnification 200,000 times).

[Production Example 1] Production of alicyclic structure-containing polymer resin In a nitrogen atmosphere, 500 parts of dehydrated cyclohexane were charged with 0.82 part of 1-hexene, 0.15 part of dibutyl ether and 0.30 part of triisobutylaluminum at room temperature. Into the reactor, the mixture was mixed, and then maintained at 45 ° C. while maintaining 8-methyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene (methyltetracyclododecene, hereinafter abbreviated as “MTD”) 200 parts and tungsten hexachloride (0.7 mass% toluene solution) 80 parts for 2 hours. Over the course of the polymerization. To the obtained polymerization solution, 1.06 part of butyl glycidyl ether and 0.52 part of isopropyl alcohol were added to inactivate the polymerization catalyst, the polymerization reaction was stopped, and a polymerization reaction solution containing a ring-opening polymer was obtained. .

  Next, 300 parts of cyclohexane is added to 700 parts of the polymerization reaction solution containing the obtained ring-opening polymer, and further 5 parts of a nickel-alumina catalyst (manufactured by JGC Chemical Co., Ltd.) is added as a hydrogenation catalyst. The mixture is heated to 200 ° C. with stirring and reacted for 4 hours, and the hydrogenation catalyst is removed by filtration to obtain a reaction solution containing 20% by mass of a hydrogenated MTD ring-opening copolymer. It was.

  Subsequently, 500 parts of cyclohexane was added to 1500 parts of the resulting solution, and this solution was poured into 1200 parts of isopropyl alcohol which was vigorously stirred to cause precipitation, and the resin was recovered by filtration. The recovered resin was dried at 120 ° C. and 0.2 kPa or less for 48 hours to obtain 100 parts of MTD ring-opening polymer hydride. This ring-opened polymer hydride had a weight average molecular weight (Mw) of 35,000, a hydrogenation rate of 99.9%, and a glass transition temperature (Tg) of 151 ° C.

Further, a film having a thickness of 40 μm was prepared from the obtained MTD ring-opening polymer hydride cyclohexane solution by a solution casting method, and a stretched film was obtained by performing uniaxial stretching at a temperature of 156 ° C. and a stretching ratio of 1.3 times. . When the refractive index of the obtained stretched film were measured, and the refractive index in the stretching direction (x), the same difference in refractive index of the direction perpendicular _{(y) (n x -n y} ) is 0.0032, the MTD The ring-opened polymer hydride was found to have positive orientation birefringence.

[Production Example 2] Production of modified alicyclic structure-containing polymer resin 30 parts of the MTD ring-opened polymer hydride obtained in Production Example 1 was dissolved in 100 parts of tert-butylbenzene. Next, 3 parts of maleic anhydride and 1 part of dicumyl peroxide were added, and the reaction was carried out in an autoclave at 135 ° C. for 6 hours. Thereafter, 100 parts of tert-butylbenzene was added, and this solution was poured into 500 parts of isopropyl alcohol which was vigorously stirred to precipitate a polymer. The polymer was collected by filtration.

The recovered polymer was dried at 100 ° C. and 0.2 kPa or less for 49 hours to obtain 33 parts of a maleic anhydride-modified polymer. The weight average molecular weight (Mw) of this modified polymer was 37,000, the glass transition temperature (Tg) was 150 ° C., and the maleic anhydride modification rate in the modified polymer was 0.5 mmol as measured by ¹ H-NMR. / G.

A uniaxially stretched film of the obtained modified polymer was produced in the same manner as in Production Example 1, and the refractive index was measured. The difference between the refractive index in the stretching direction (x) and the refractive index in the perpendicular direction (y) ( n _x -n _y) is 0.0030, the modified polymer was found to have a positive orientation birefringence.

[Production Example 3] Hydrophilic treatment of inorganic layered crystal compound 100 parts of synthetic smectite (Smecton SA: manufactured by Kunimine Kogyo Co., Ltd.), which is a layered silicate, is uniformly dispersed in 1000 parts of distilled water at 60 ° C to obtain a smectite dispersion. Obtained. Next, a solution in which 20 parts of distearyldimethylammonium chloride was dissolved in 300 parts of distilled water was slowly added to the dispersion while stirring the scumetite dispersion. After stirring at 60 ° C. for 3 hours, The solid was separated by filtration. The solid was added to 500 parts of distilled water at 60 ° C. and redispersed, and then filtered again to separate the solid. After repeating this dispersion and filtration three times, water was removed by freeze drying to obtain organophilic smectite.

Next, 10 parts of the obtained organophilic smectite was dispersed and swollen in 90 parts of toluene to prepare a transparent dispersion. A part of this dispersion was applied on a glass plate and dried to form a transparent film having a thickness of 5 μm. When the cross section in the thickness direction of the transparent film was observed with a scanning electron microscope, it was confirmed that the inorganic layered compound was uniformly oriented substantially in the plane direction. The Measurement of the three-dimensional refractive index of the transparent film, and the plane x-direction, the refractive index difference between the y-direction (n x _{-n y)} is 0, the x direction and the z-direction (thickness direction) refractive index difference _(n x -n _z) is 0.009.

  From this, a rotating body with an arbitrary direction in the plane of the obtained inorganic / organic composite as an axis is considered, and if this rotating body is oriented in this axial direction, the axis is more than the refractive index in the axial direction. It was found that the refractive index was larger in the vertical direction, that is, in any direction in the plane with this axis as the normal. That is, this inorganic / organic composite has positive orientation birefringence.

[Production Example 4] Preparation of Inorganic / Organic Complex Dispersion 1 5 parts of organophilic smectite obtained in Production Example 3 was dispersed and swollen in 90 parts of toluene to prepare a transparent dispersion. 4 parts of 4-biphenylcarboxylic acid was added here, and it stirred at 50 degreeC for 3 hours, and obtained the substantially transparent inorganic and organic complex dispersion liquid 1.

The dispersion 1 was applied to a glass plate in the same manner as in Production Example 3 and dried to form a film. When the three-dimensional refractive index of the film was measured, the difference in refractive index between the in-plane x direction and the y direction (nx ₎ -n _y) is 0, the refractive index difference between the x direction and the z-direction (thickness direction) _(n x -n _z) was -0.075. Therefore, it was found that this inorganic / organic composite has negative orientation birefringence.

[Production Example 5] Preparation of Inorganic / Organic Complex Dispersion 2 Inorganic / organic complex in the same manner as in Production Example 4 except that 3 parts of 4-cyclohexylbenzoic acid was used instead of 3 parts of 4-biphenylcarboxylic acid. Dispersion 2 was obtained.
As in Production Example 3, this dispersion 2 was applied onto a glass plate and dried to form a film, and when the three-dimensional refractive index of the film was measured, the difference in refractive index between the in-plane x direction and y direction ( n _x -n _y) is 0, the refractive index difference between the x direction and the z-direction (thickness direction) _(n x -n _z) was -0.055. Therefore, it was found that this inorganic / organic composite has negative orientation birefringence.

[Example 1]
70 parts of the MTD ring-opening polymer hydride obtained in Production Example 1 and 20 parts of the modified polymer obtained in Production Example 2 were dissolved in 300 parts of toluene to obtain a polymer solution. This polymer solution was mixed with 100 parts of the inorganic / organic composite dispersion 1 obtained in Production Example 4, and 0.1 part of an antioxidant (manufactured by Ciba Specialty Chemicals; Irganox 1010) was added. After dissolution, the mixture was stirred at room temperature for 30 minutes to prepare a polymer solution in which the inorganic / organic composite was dispersed.

  Next, the above solution (solid content concentration 20%) was heated to 220 ° C., and the solvent was removed and concentrated using a flash separator (manufactured by Hitachi, Ltd.) to obtain a concentrated solution having a solid content concentration of 60%. Concentration conditions were performed in an atmosphere having an oxygen concentration of 0.1% by volume while heating at a jacket temperature of 160 ° C. with a solution supply rate of 250 kg / hour, a pressure of 360 kPa.

  Next, the solvent component is removed from the concentrated solution using two cylindrical thin film dryers (manufactured by Hitachi, Ltd.) connected in series, and the molten resin composition is discharged from the second cylindrical thin film dryer. Was derived. The operating conditions of the cylindrical thin film dryer are as follows: First unit: temperature 270 ° C., pressure 15 kPa, second unit: temperature 285 ° C., pressure 1 kPa or less, solution (and molten resin composition from which solvent components have been removed) The residence time was 7 hours in total.

  Biaxial kneading of a molten resin composition continuously derived from a cylindrical thin film dryer (second unit) with a polymer filter (manufactured by Fuji Filter) equipped with a stainless sintered filter having a pore size of 5 μm Introducing a heat insulation pipe connecting the discharge port of the polymer filter and the barrel of the twin-screw kneading extruder at the kneading part of the extruder (Toshiba Machine Co., Ltd., TEM-35, screw diameter 37 mm, L / D = 45) The mixture was kneaded at a screw rotation speed of 250 rpm, a resin temperature of 210 ° C. and a feed rate of 10 kg / hour, extruded into a strand shape, and cut with a strand cutter to obtain a resin composition pellet.

  Using the obtained pellets, using a T-die type film melt extrusion molding machine (T-die width 250 mm), a film having a thickness of 100 μm and a width of 250 mm under molding conditions of a molten resin temperature of 250 ° C. and a T-die temperature of 250 ° C. Was extruded. The total light transmittance, haze, and retardation at a wavelength of 550 nm of the obtained film were measured. Further, this film was uniaxially stretched at a temperature of 156 ° C. and a stretch ratio of 1.5 times, and retardation at a wavelength of 550 nm was measured. These results are shown in Table 1.

  In addition, when the stretch direction of the stretched film is x, the direction perpendicular to the stretch direction in the plane is y, and the thickness direction is z, the XY cross section, the xz cross section, and the yz cross section are observed with a transmission electron microscope. went. In both the x-y cross section and the x-z cross section, it is observed that a linear shape having a width of 1 to 3 nm and a number average length of 50 nm is oriented in the stretching direction (x direction) and uniformly dispersed. It was. Further, in the yz cross section, the same linear shape was observed in an irregular direction and uniformly dispersed. Assuming that the arbitrary direction in the plane of the inorganic / organic composite is x and the thickness direction is z, from the above observation results, the x direction of the inorganic / organic composite in this stretched film is parallel to the stretch direction of the film. It was found that the z direction was distributed in an arbitrary direction perpendicular to the stretching direction of the film.

[Example 2]
Resin composition as in Example 1 except that 100 parts of the inorganic / organic composite dispersion 2 obtained in Production Example 5 was used instead of 100 parts of the inorganic / organic composite dispersion obtained in Production Example 4. Product pellets were obtained. Extruded films and stretched films were produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.
The orientation direction of the inorganic / organic composite in the stretched film was the same as in Example 1.

[Comparative Example 1]
Resin composition in the same manner as in Example 1 except that 100 parts of the organophilic smectite dispersion obtained in Production Example 3 was used in place of 100 parts of the inorganic / organic composite dispersion 2 obtained in Production Example 4. Product pellets were obtained. Extruded films and stretched films were produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.
The orientation direction of the organophilic smectite in the stretched film was the same as in Example 1.

[Comparative Example 2]
Extruded films and stretched films were produced and evaluated under the same conditions as in Example 1 using the MTD ring-opening polymer hydride obtained in Production Example 1. The results are shown in Table 1.

From Table 1, it is confirmed that the resin composition of the present invention has high transparency, and the obtained molded body has little retardation even when orientation strain is applied, and is useful as an optical molded body. did it.

Claims (4)

  An inorganic / organic composite obtained by supporting an organic low molecular weight compound on an inorganic layered compound is dispersed in a transparent resin, and the inorganic / organic composite and the transparent resin are oriented birefringence with opposite signs. A low birefringence resin composition characterized by exhibiting properties. The low birefringent resin composition according to claim 1, wherein the inorganic layered compound is a layered silicate.   The low birefringent resin composition according to claim 1, wherein the transparent resin is an alicyclic structure-containing polymer resin. The optical molded object formed by shape | molding the resin composition in any one of Claims 1-3.