JP2010204586A - Phase difference film and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a phase difference film having a predetermined retardation level, high transparency, and a phase difference superior in heat resistance. <P>SOLUTION: In the phase difference film prepared by curing a resin composition comprising a predetermined silicone resin (1), a photopolymerization initiator (2) and/or a thermal polymerization initiator (3), a variation of a phase difference value of the phase difference film after heating treatment at 100°C for 10 hours is 0-20 nm. In a method for manufacturing the phase difference film, a resin molded product is obtained by primary curing, wherein unsaturated groups of the component (1) is reduced by 0.1-50%, of the resin composition, the resin molded product is cut into a predetermined shape and fixed to a drawing tool to be drawn in an optional direction at a drawing ratio within the range of 5-700% to obtain a drawn resin molded product, secondary curing of the drawn resin molded product is carried out by heating and/or energy ray irradiation while fixing the drawn resin molded product in the drawing tool, and the cured drawn resin molded product is cooled to room temperature. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a retardation film and a method for producing the same, and in particular, has a high transparency, has a small amount of change in retardation even after heating, and has an excellent performance and a method for producing the same. About.

  In recent years, liquid crystal display devices have been widely used in place of CRTs of cathode ray tubes. In these liquid crystal display devices, a retardation film is used for eliminating image coloring or expanding a viewing angle. Further, in a projection type projector and a laser beam beam splitter, a retardation film is used as a mutual conversion element between linearly polarized light and circularly polarized light. Furthermore, in touch panel applications, the introduction of a retardation film is required to reduce external light reflection and improve visibility.

  These retardation films are films made of birefringent materials used to change the relative phase of polarized light components, and generally synthetic resin oriented films are used as birefringent layers. It has been. Examples of the structure of the retardation film include a single-layer structure composed of one birefringent layer, a multilayer structure in which two or more birefringent layers having the same or different birefringence are laminated, and a protective layer. (For example, refer to Patent Document 1).

  For example, the retardation film for liquid crystal displays is optically uniform on the entire surface of the birefringent layer in order to obtain clear colors and fine images, and the optical characteristics do not change with changes in temperature and humidity. It is necessary. In particular, when it is used for a liquid crystal display panel mounted on an automobile, use under severe conditions is predicted, and therefore, a heat-resistant temperature of at least 60 ° C. or higher, preferably 80 ° C. or higher, more preferably 100 ° C. or higher is required. Is done. However, as a conventional retardation film, a polycarbonate resin (for example, see Patent Document 2) or a norbornene-based resin (for example, see Patent Document 3), which is a thermoplastic resin, is mainly used, and sufficient heat resistance and weather resistance are used. Sex is not obtained.

  Further, in the case of a thermoplastic resin having a high Tg (glass transition temperature), a sheet is generally produced by a solution casting method, but a stretch-oriented film is excellent in surface smoothness but poor in productivity. In addition, since the solvent remains, there is a problem that it cannot be used depending on the use environment.

JP-A-5-2108 JP 2006-143831 A JP 2006-301522 A WO2008 / 123347

  Accordingly, an object of the present invention is to provide a retardation film having high transparency and having excellent performance with little change in retardation even after heating, and a method for producing the same.

  The present inventors have already proposed the retardation film according to Patent Document 4, but as a result of intensive studies to achieve the above object, by using a resin composition containing a specific silicone resin, The inventors have found that a retardation film having high transparency and further improving the decrease in retardation due to aging even after heating can be obtained, and the present invention has been completed.

〔式中、Ｘは少なくとも一つのケイ素原子と少なくとも一つの芳香族基を有する２価の基であり、Ｒ₁は（メタ）アクリロイル基を有する有機官能基であり、Ｒ₂は（メタ）アクリロイル基若しくはビニル基を有する有機官能基、炭素数１〜２５の脂肪族炭化水素、炭素数６〜１５の置換若しくは無置換の環式脂肪族、又は炭素数６〜１５の置換若しくは無置換の環式芳香族を表し、ｌ＝１、ｍ＝１〜３、ｎは２〜２９０である。〕 That is, the present invention comprises (1) a silicone resin having a number average molecular weight of 1000 to 80000 represented by the following general formula (1), (2) a photopolymerization initiator and / or (3) a thermal polymerization initiator. A retardation film obtained by curing a resin composition comprising: a retardation value change amount of the retardation film after a heat treatment at 100 ° C. for 10 hours is in a range of 0 to 20 nm. It is a retardation film.

[Wherein X is a divalent group having at least one silicon atom and at least one aromatic group, R ₁ is an organic functional group having a (meth) acryloyl group, and R ₂ is (meth) acryloyl. An organic functional group having a group or a vinyl group, an aliphatic hydrocarbon having 1 to 25 carbon atoms, a substituted or unsubstituted cyclic aliphatic having 6 to 15 carbon atoms, or a substituted or unsubstituted ring having 6 to 15 carbon atoms Represents a formula aromatic, 1 = 1, m = 1-3, n is 2-290. ]

〔式中、Ｘは少なくとも一つのケイ素原子と少なくとも一つの芳香族基を有する２価の基であり、Ｒ₁は（メタ）アクリロイル基を有する有機官能基であり、Ｒ₂は（メタ）アクリロイル基若しくはビニル基を有する有機官能基、炭素数１〜２５の脂肪族炭化水素、炭素数６〜１５の置換若しくは無置換の環式脂肪族、又は炭素数６〜１５の置換若しくは無置換の環式芳香族を表し、ｌ＝１、ｍ＝１〜３、ｎは２〜２９０である。〕
樹脂組成物を少なくとも１枚の支持体で支持し、上記（１）成分の不飽和基を０．１％〜５０％減少させる一次硬化により樹脂成形体を得た後、この樹脂成形体を所定の形状に切り出して延伸治具に固定し、任意方向に延伸倍率５〜７００％の範囲で延伸させて延伸樹脂成形体を得た後、この延伸樹脂成形体を延伸治具に固定した状態で更に加熱及び／又はエネルギー線を照射して二次硬化させ、その後、室温まで冷却することを特徴とする位相差フィルムの製造方法である。 The present invention also includes (1) a silicone resin having a number average molecular weight of 1000 to 80000 represented by the following general formula (1), and (2) a photopolymerization initiator and / or (3) a thermal polymerization initiator. A phase difference film using a resin composition comprising:

[Wherein X is a divalent group having at least one silicon atom and at least one aromatic group, R ₁ is an organic functional group having a (meth) acryloyl group, and R ₂ is (meth) acryloyl. An organic functional group having a group or a vinyl group, an aliphatic hydrocarbon having 1 to 25 carbon atoms, a substituted or unsubstituted cyclic aliphatic having 6 to 15 carbon atoms, or a substituted or unsubstituted ring having 6 to 15 carbon atoms Represents a formula aromatic, 1 = 1, m = 1-3, n is 2-290. ]
The resin composition is supported by at least one support, and after obtaining a resin molding by primary curing that reduces the unsaturated group of the component (1) by 0.1% to 50%, the resin molding is predetermined. In a state where the stretched resin molded body is fixed to the stretching jig after being cut in the shape of, fixed to the stretching jig, and stretched in a range of 5 to 700% in any direction to obtain a stretched resin molded body. Further, it is a method for producing a retardation film, wherein the film is secondarily cured by irradiation with heat and / or energy rays, and then cooled to room temperature.

〔式中、Ｘは少なくとも一つのケイ素原子と少なくとも一つの芳香族基を有する２価の基であり、Ｒ₁は（メタ）アクリロイル基を有する有機官能基であり、Ｒ₂は（メタ）アクリロイル基若しくはビニル基を有する有機官能基、炭素数１〜２５の脂肪族炭化水素、炭素数６〜１５の置換若しくは無置換の環式脂肪族、又は炭素数６〜１５の置換若しくは無置換の環式芳香族を表し、ｌ＝１、ｍ＝１〜３、ｎは２〜２９０である。〕 In this invention, the resin composition which comprises retardation film contains the silicone resin which exists in the range of the number average molecular weight 1000-80000 represented by following General formula (1) as (1) component.

Wherein, X is a divalent group having at least one aromatic group and at least one silicon atom, R ₁ is an organic functional group having a (meth) acryloyl group, R ₂ is (meth) acryloyl An organic functional group having a group or a vinyl group, an aliphatic hydrocarbon having 1 to 25 carbon atoms, a substituted or unsubstituted cyclic aliphatic having 6 to 15 carbon atoms, or a substituted or unsubstituted ring having 6 to 15 carbon atoms Represents a formula aromatic, 1 = 1, m = 1-3, n is 2-290. ]

  (1) The silicone resin used as the component can be produced by a generally used method. That is, a method of synthesizing from a polyol, a dichlorosilane compound, and a compound having a polymerizable unsaturated group and a hydroxyl group at the terminal. In that case, the silicone resin used for the resin composition of this invention can be obtained by adjusting suitably the molecular weight of a raw material substance, or the molar ratio at the time of reaction.

  The polyol is preferably a silicon compound having two hydroxyl groups in one molecule and having at least one aromatic group, for example, an aromatic compound having two silanol groups and optionally having a substituent. A compound having one or more aromatic rings, specifically 1,4-bis (hydroxydimethylsilyl) benzene or the like, and, for example, at least one aromatic group which may have a substituent. Specific examples thereof include diphenylsilane diol and the like.

  Examples of the dichlorosilane compound include dimethyldichlorosilane, acetoxypropylmethyldichlorosilane, (3-acryloxypropyl) methyldichlorodilane, allylmethyldichlorosilane, allylphenyldichlorosilane, and bis [2- (chlorodimethylsilylethyl) benzene. 1,3-bis (chloromethyldimethylsiloxy) benzene, butenylmethyldichlorosilane, t-butylmethyldichlorosilane, t-butylphenyldichlorosilane, 2- (carbomethoxy) ethylmethyldichlorosilane, [(chloromethyl) Phenylethyl] dimethylchlorosilane, [2- (3-cyclohexenyl) ethyl] methyldichlorosilane, chloromethylmethyldichlorosilane, cyclotetramethylenedichlorosilane, dibenzyloxydichlorosila 1,3-dichloro-1,3-diphenyl-1,3-dimethyldichlorosilane, 1,5-dichlorohexamethyltrisiloxane, 1,7-dichlorooctamethyltetrasiloxane, 1,3-dichlorotetramethyldisiloxane, , 3-dichlorotetraphenyldisiloxane, dicyclohexyldichlorosilane, diphenyldichlorosilane, di (p-tolyl) dichlorosilane, divinyldichlorosilane, ethylmethyldichlorosilane, methacryloxypropyldichlorosilane, 3- (p-methoxyphenyl) propyl Methyldichlorosilane, phenylmethyldichlorosilane, phenylmethyldichlorosilane, 1,1,3,3-tetracyclopentyldichlorodisiloxane, p-tolylmethyldichlorosilane, (3,3,3-tylfluoropro Pyr) methyldichlorosilane, vinylmethyldichlorosilane, vinylphenyldichlorosilane, divinyldichlorosilane, methylphenyldichlorosilane, 1,4-bis (dimethylchlorosilyl) benzene, 1,1,3,3,5,5-hexamethyl- Examples include 1,5-dichlorotrisiloxane and 1,7-dichloro-1,1,3,3,5,5,7,7-octamethyltetrasiloxane.

  Examples of the compound having a polymerizable unsaturated group and a hydroxyl group at the terminal include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2- ( (Meth) acryloyloxyethyl-2-hydroxyethylphthalic acid, pentaerythritol tri (meth) acrylate, 3-acryloyloxyglycerin mono (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy-1- (meth) Acryloxy-3- (meth) acryloxypropane, glycerin di (meth) acrylate, polypropylene glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, poly ε-caprolactone mono (meth) acrylate Rate, 4-hydroxybutyl (meth) acrylate, .epsilon.-caprolactone mono (meth) acrylate, various types of epoxy acrylate.

  The conditions for obtaining the silicone resin in the present invention are as follows: at room temperature, a basic compound equal to or more than hydrogen chloride generated during the reaction is added to the reaction system, and the molecular weight is adjusted by the molar ratio of the polyol and the dichlorosilane compound. A method of adding a compound having a polymerizable unsaturated group and a hydroxyl group at the terminal is preferred. As the molar ratio of the polyol and the dichlorosilane compound is closer to 1: 1, a higher molecular weight can be obtained. The molar ratio of the polyol to the dichlorosilane compound and the compound having a polymerizable unsaturated group and a hydroxyl group at the terminal is 10: 15: 4, more preferably 20: 21: 4.

  Moreover, (2) photoinitiator and / or (3) thermal polymerization initiator are mix | blended with the resin composition in this invention as a radical polymerization initiator. (2) When only the photopolymerization initiator is blended, the amount added is in the range of 0.1 to 3 parts by weight with respect to the total 100 parts by weight of the resin composition. Is preferred. (3) When only the thermal polymerization initiator is blended, the amount added is preferably in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the total resin composition. When (2) a photopolymerization initiator and (3) a thermal polymerization initiator are blended, (2) the photopolymerization initiator is 0.01 to 1 part by weight relative to 100 parts by weight of the total resin composition, (3) The thermal polymerization initiator is preferably in the range of 0.01 to 10 parts by weight. In each formulation, if the amount is less than the above range, crosslinking is insufficient, and thus it is difficult to fix the stretch orientation. Even if the content exceeds the range, no improvement in the reaction rate can be expected.

  As said (2) photoinitiator, compounds, such as an acetophenone series, a benzoyl series, a benzophenone series, a thioxanthone series, and an acyl phosphine oxide series, can be used conveniently. Specifically, trichloroacetophenone, diethoxyacetophenone, 1-phenyl-2-hydroxy-2-methylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- (4-methylthiophenyl) -2 -Morpholinopropan-1-one, benzoin methyl ether, benzyldimethyl ketal, benzophenone, thioxanthone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, methylphenylglyoxylate, camphorquinone, benzyl, anthraquinone, Michler's ketone, etc. can do. Moreover, the photoinitiator adjuvant and the sharpening agent which show an effect in combination with a photoinitiator can also be used together.

  As the above (3) thermal polymerization initiator, known organic peroxides classified into ketone peroxide, peroxyketal, hydroperoxide, diallyl peroxide, diacyl peroxide, peroxyester, peroxydicarbonate, And azo compounds. Specific examples include benzoyl peroxide, dicumyl peroxide, diisopropyl peroxide, di-t-butyl peroxide, t-butyl peroxybenzoate, 1,1-bis (t-butylperoxy) -3,3, 5-trimethylcyclohexane, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3, 3-isopropyl hydroperoxide, t-butyl hydroperoxide, dicumyl peroxide, dicumyl hydroper Oxide, acetyl peroxide, bis (4-t-butylcyclohexyl) peroxydicarbonate, diisopropylperoxydicarbonate, isobutyl peroxide, 3,3,5-trimethylhexanoyl peroxide, lauryl peroxide, azobisiso Chironitoriru include azobis carboxamido like.

  The resin composition in the present invention has at least one unsaturated group capable of radical polymerization with the component (1) within the range not deteriorating the function as the retardation film, in addition to the components (1) to (3). It can contain the resin which has. This component is preferably an alicyclic monomer having an unsaturated group, an aliphatic monomer having an unsaturated group, or a cage silsesquioxane having a substituent containing an unsaturated group. One or a mixture of two or more of these can be used. Examples include cage silsesquioxane, dicyclopentanyl diacrylate, trimethylolpropane trimethacrylate, tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, bisphenol A diglycidyl ether diacrylate, tetraethylene glycol Examples include diacrylate, neopentyl glycol diacrylate of hydroxypivalate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, and the like.

  Furthermore, in addition to the above components (1) to (3), various additives can be added as long as the function as a retardation film is not lowered. Various additives include organic / inorganic fillers, plasticizers, flame retardants, heat stabilizers, antioxidants, light stabilizers, UV absorbers, lubricants, antistatic agents, mold release agents, foaming agents, nucleating agents, and coloring agents. Examples thereof include a crosslinking agent, a dispersion aid, and a resin component.

  In the present invention, the production process of the retardation film is as follows. That is, the resin composition is primarily cured to obtain a resin molded body, and the resin molded body is oriented by stretching. And the obtained stretched resin molding is secondarily cured to obtain a retardation film. Among these, when the resin composition is primarily cured to obtain a partially molded resin-molded product, the method includes heating means or energy beam irradiation means, and among these heating means, the heating means is 25 to 200. It is preferable to heat in the range of ° C., preferably 25 to 180 ° C. On the other hand, the energy beam means is preferably irradiated with energy beams such as an electron beam of 300 to 6000 mj, ultraviolet rays and visible light.

  When primary curing is performed by irradiating energy rays such as ultraviolet rays or visible light, for example, a mold in which a plurality of supports are assembled, and at least one support is transparent to transmit ultraviolet rays such as quartz glass. Injecting the resin composition into a mold made of the material, irradiating the ultraviolet light with an ultraviolet lamp, polymerizing and curing the resin composition accommodated by at least the ultraviolet light that has passed through the transparent material, and removing the mold from the mold Thus, a method of obtaining a resin molded body having a desired shape can be employed. When a mold is not used, for example, a steel belt is used as a support, a resin composition is applied onto a moving steel belt with a doctor blade or a roll coater, and polymerized and cured with the ultraviolet lamp described above. By this, the method etc. which obtain a sheet-like resin molding can be illustrated. In the case of the heating means, the resin composition injected into the mold or the resin composition applied onto the steel belt may be heated in a predetermined temperature range.

  When primary curing of the resin composition is performed by energy ray irradiation, a resin molded body can be obtained by preferably irradiating ultraviolet rays having a wavelength of 10 to 400 nm or visible rays having a wavelength of 400 to 700 nm. The wavelength of light to be used is not particularly limited, but near ultraviolet light having a wavelength of 200 to 400 nm is particularly preferable. As a lamp used as an ultraviolet ray generation source, a low-pressure mercury lamp (output: 0.4 to 4 W / cm), a high-pressure mercury lamp (40 to 160 W / cm), an ultra-high pressure mercury lamp (173 to 435 W / cm), a metal halide lamp (80-160 W / cm), a pulse xenon lamp (80-120 W / cm), an electrodeless discharge lamp (80-120 W / cm), etc. can be illustrated.

  Moreover, when obtaining a resin molding by primary curing, it is made to primary cure until the unsaturated group of said (1) component reduces 0.1 to 50% in total. In order to control the reduction rate of unsaturated groups (hereinafter referred to as “reaction rate”), it is preferable to adjust the heating conditions or the irradiation amount of the lamp. In the case of energy ray irradiation, the irradiation range can be determined by the type of lamp used and the resin composition. For example, in the case of an ultra-high pressure mercury lamp (333 W / cm), a desired reaction rate can be obtained by arbitrarily adjusting the dose within a range of 400 to 6000 mj. The dose can be adjusted according to the irradiation time. However, if the irradiation time is too short, the reproducibility of the reaction rate cannot be obtained, and if the irradiation time is long, the productivity deteriorates. It is preferable to do. On the other hand, in the case of a heating means, the temperature should be gradually raised from around room temperature, and the heating time varies depending on the type of thermal polymerization initiator and the resin composition, but is preferably about 20 minutes to 4 hours. .

  If the reaction rate of the primary-cured resin molded product is too low, it is difficult to maintain the sheet shape and may be easily broken. On the other hand, if it is too high, the draw ratio is low, and the desired high retardation value is obtained. I can't get it. Therefore, the reaction rate is preferably 0.1% to 50%, more preferably 0.1% to 30%.

  Thus, the thickness of the resin molding obtained is not specifically limited, It can determine suitably according to the intended purpose etc. of the stretched film (retardation film) obtained. In general, the film is preferably in the form of a film having a thickness of 5 to 500 μm from the viewpoint of obtaining a uniform stretched film by a stable stretching process.

  In this invention, the phase difference film which expresses birefringence can be obtained by orienting the resin molding obtained by said method by extending | stretching. That is, the resin molded body obtained above is cut into a predetermined shape, fixed to a stretching jig, and stretched to obtain a stretched resin molded body. By stretching the resin molded body obtained above, the resin molded body is stretched and oriented to develop birefringence. As a means for stretching and orientation, for example, uniaxial stretching such as free width uniaxial stretching, constant width uniaxial stretching, biaxial stretching such as sequential biaxial stretching, simultaneous biaxial stretching, and the like can be used, preferably in the width direction. It is preferable to perform uniaxial stretching. Moreover, there is no restriction | limiting in particular about the extending | stretching jig | tool which fixes the resin molding cut out to the defined shape, For example, it can process and use metals, such as iron, aluminum, copper, and brass, and a plastic which has heat resistance. it can. Needless to say, these have sufficient rigidity against the stress of the resin molded body caused by stretching.

  The temperature at which the resin molded body is stretched and oriented varies depending on the elastic modulus obtained from the dynamic viscoelasticity measurement of the resin molded body, but is preferably 1000 to 0.01 MPa for the purpose of reducing the residual stress after stretching. A temperature range showing a range of 100 to 0.1 MPa is more preferable.

  When the stretching speed at which the resin molded body is stretched and oriented becomes small, the retardation value decreases due to thermal relaxation, or breaks easily in the subsequent secondary curing step. Therefore, the stretching speed is preferably 1 mm / min or more. However, if the speed is too high, the film will be cut or detached from the jig in the stretching apparatus, and therefore, it is more preferably in the range of 1 mm / min to 10 mm / min.

  Moreover, a desired retardation value can be obtained by adjusting the stretching ratio when the resin molded body is stretched. In the method for producing a retardation film of the present invention, the film is stretched in a range of 5 to 700%, preferably in a range of 5 to 500%. If the stretch rate is lower than 5%, it is difficult to develop a phase difference. Conversely, if it is higher than 500%, the film may be cut.

  The film thus uniaxially stretched is secondarily cured by any of the following methods for the purpose of fixing the orientation of the film. That is, in a state where the stretched resin molded body is fixed to a stretching jig, the resin is further cured by heating and / or irradiation with energy rays, so that the reaction rate is almost 100% and the curing reaction is terminated.

  As a first method, it is preferable to hold the stretched resin molded body at a predetermined temperature for a predetermined time while being fixed to the stretching jig so as to maintain the stretched width after stretching. The temperature at this time is not less than the stretching temperature and can be selected from a wide range from room temperature to around 200 ° C. depending on the selection of the thermal polymerization initiator. The holding time is preferably 20 minutes to 4 hours. At this time, the stretching jig for fixing the stretched resin molded body preferably has a mechanism for adjusting the tension of the jig for fixing in order to maintain the stretching width. When the tension is too low, the shrinkage in the stretching direction from the relaxation of orientation due to heat is large, and the orientation after stretching is not sufficiently maintained. On the other hand, if it is too high, cutting due to curing shrinkage occurs, making it difficult to produce a film. The film thus heat-treated is cooled to room temperature while maintaining the stretched width.

  As a second method, it is preferable to irradiate energy rays in the range of 3000 mj to 20000 mj while the stretched resin molded body is fixed to the stretching jig so as to maintain the stretched width after stretching.

  As a third method, after irradiating energy rays in the range of 3000 mj to 20000 mj with the stretched resin molded body being fixed to the stretching jig so as to maintain the stretched width after stretching, it is predetermined for a predetermined time. It is better to keep the temperature. The temperature and holding time at this time are the same as in the first case. By irradiating energy rays, it is possible to increase the breaking strength and suppress the breakage in secondary curing. The film thus heat-treated is cooled to room temperature while maintaining the stretched width.

  As a fourth method, if necessary, a curable resin containing a photopolymerization initiator on at least one surface of a stretched resin molded body before secondary curing or a stretched resin molded body after secondary curing. It may be coated and irradiated with energy rays of 1000 to 20000 mj to form a photocurable resin layer. That is, with the stretched resin molded body removed from the stretching jig or fixed to the stretching jig, a curable resin containing a photopolymerization initiator is applied to at least one surface and irradiated with the energy beam at least. By forming another layer of the photocurable resin layer, the stretched resin molded body can be fixed. This method may be used as an auxiliary means to the method using a stretching jig.

  As a fifth method, if necessary, a curable resin containing a thermal polymerization initiator on at least one surface of the stretched resin molded body before secondary curing or the stretched resin molded body after secondary curing. You may make it form a thermosetting resin layer by applying and heat-processing for 20 minutes-4 hours at the temperature of 25-200 degreeC. That is, with the stretched resin molded body removed from the stretching jig or fixed to the stretching jig, a curable resin containing a thermal polymerization initiator is applied to at least one surface, and thermosetting at the above temperature and time. By forming the resin layer, the stretched resin molded body can be fixed. Furthermore, you may use together with the means specified as a 3rd method. This method may be used as an auxiliary means to the method using a stretching jig.

  As another method, if necessary, curing in a state where a photopolymerization initiator and a thermal polymerization initiator are included on at least one surface of the stretched resin molded body before secondary curing or the stretched resin molded body after secondary curing. The resin composition is formed by applying a heat-resistant resin, irradiating energy rays of 400 to 10000 mj to form a curable resin layer, and performing a heat treatment at a temperature of 25 to 200 ° C. for 20 minutes to 4 hours. The reduction rate of the acryloyl group in the inside may be almost 100%. That is, with the stretched resin molded body removed from the stretching jig or fixed to the stretching jig, a curable resin containing a photopolymerization initiator and a thermal polymerization initiator is applied to at least one surface, and the energy It is possible to fix the stretched resin molded body by irradiating a line to form at least another curable resin layer and heating. This method may be used as an auxiliary means to the method using a stretching jig.

For the curable resin to be applied to one surface of the stretched resin molded body before secondary curing or the stretched resin molded body after secondary curing, it has transparency and weather resistance when a retardation film is obtained, and Is not particularly limited as long as it can form a resin layer having a Tg of 200 ° C. or higher, but a silicone resin composition as described in JP-A-2006-89685 is preferably used. That is, it is represented by the general formula [RSiO _3/2 ] _n (where R is an organic functional group having a (meth) acryloyl group, and n is 8, 10 or 12), and has a cage structure in the structural unit. poly silicone resin to organosilsesquioxane a main component, -R ₃ -CR ₄ = CH ₂ or -CR ₄ = CH ₂ in the molecule (wherein, R ₃ is an alkylene group having, an alkylidene group or a -OCO A urethane bond having a number average molecular weight of 2500 or more and comprising at least one unsaturated group represented by the formula:-R ₄ represents hydrogen or an alkyl group, and capable of radical copolymerization with the silicone resin. It is preferable to use a silicone resin composition in which an oligomer having an unsaturated compound capable of radical copolymerization with the other silicone resin is blended in a polymerization ratio of 5 to 40:50 to 90: 0 to 30. Is preferred.

And the retardation film obtained by this invention is the range whose phase difference value change amount of the retardation film after heat-processing for 10 hours at 100 degreeC is 0-20 nm. Here, the amount of change in the retardation value of the retardation film after the heat treatment refers to the secondary curing or the application of a curable resin containing a photopolymerization initiator and / or a thermal polymerization initiator, and light and / or heat. The amount of change between the retardation value measured immediately after forming the curable resin layer and the retardation value after being held at 100 ° C. for 10 hours. The retardation film of the present invention preferably has an in-plane retardation value Re of 5 to 150 nm at a wavelength of 550 nm at d = 250 μm. The phase difference value Re is obtained from the following equation. Moreover, the preferable retardation value Re here is a value obtained by measurement at a time point of holding at 100 ° C. for 10 hours.
_{Re = (n x -n y)} d
[N _x: x-axis direction of the refractive index, n _y: y-axis direction of the refractive index, d: film thickness]

  According to the present invention, it is possible to obtain an excellent retardation film having a high transparency and having a small amount of change in retardation even after heating, for example, an in-vehicle touch panel for use in a high temperature environment, It can be suitably used for liquid crystal display devices.

  Examples and the like are described below, but the present invention is not limited thereto. The silicone resin and saddle type silicone resin used in the following examples were obtained by the methods shown in the following synthesis examples.

[Synthesis Example 1] (Preparation of linear silicone resin 1)
A reaction vessel was charged with 20 g of 1,4-bis (hydroxydimethylsilyl) benzene and dried in vacuo. A stirrer and a dropping funnel were attached, and 88 ml of tetrahydrofuran (THF) was charged as a solvent to the reaction vessel, and 4 ml of pyridine was charged as a base catalyst. To the dropping funnel, 12 ml of vinylmethyldichlorosilane was added and dropped in an ice bath over 15 minutes while stirring the reaction vessel. After completion of dropping, the mixture was stirred at room temperature for 2 hours. After stirring for 2 hours, 0.5 ml of dimethyldichlorosilane was added dropwise and stirred for 30 minutes. Further, 1.85 ml of 2-hydroxyethyl acrylate was added dropwise and stirred for 1 hour. After stirring, it was dissolved in 400 ml of toluene. The reaction solution was washed with saturated brine until neutral, and then dehydrated with anhydrous magnesium sulfate. Anhydrous magnesium sulfate was filtered off and concentrated to obtain 31 g of a silicone resin. The obtained resin was dissolved in 5 ml of toluene and then reprecipitated with methanol to remove the supernatant. By concentrating, 30 g of a silicone resin was obtained. This silicone resin was a pale white viscous liquid soluble in various organic solvents.

[Synthesis Example 2] (Preparation of linear silicone resin 2)
A reaction vessel was charged with 20 g of 1,4-bis (hydroxydimethylsilyl) benzene and dried in vacuo. A stirrer and a dropping funnel were attached, and 88 ml of tetrahydrofuran (THF) was charged as a solvent to the reaction vessel, and 4 ml of pyridine was charged as a base catalyst. To the dropping funnel, 12 ml of methacrylmethyldichlorosilane was added, and the mixture was added dropwise in an ice bath over 15 minutes while stirring the reaction vessel. After completion of dropping, the mixture was stirred at room temperature for 2 hours. After stirring for 2 hours, 0.5 ml of dimethyldichlorosilane was added dropwise and stirred for 30 minutes. Further, 1.85 ml of 2-hydroxyethyl acrylate was added dropwise and stirred for 1 hour. After stirring, it was dissolved in 400 ml of toluene. The reaction solution was washed with saturated brine until neutral, and then dehydrated with anhydrous magnesium sulfate. Anhydrous magnesium sulfate was filtered off and concentrated to obtain 31 g of a silicone resin. The obtained resin was dissolved in 5 ml of toluene and then reprecipitated with methanol to remove the supernatant. By concentrating, 30 g of a silicone resin was obtained. This silicone resin was a pale white viscous liquid soluble in various organic solvents.

[Synthesis Example 3] (Preparation of bowl-shaped silicone resin)
A method for obtaining a cage-type silicone resin having methacryloyl groups on all silicon atoms was carried out as follows with reference to a known synthesis method (Japanese Patent Laid-Open No. 2006-089685).

  A reaction vessel equipped with a stirrer, a dropping funnel, and a thermometer was charged with 40 ml of 2-propanol (IPA) as a solvent and 5% tetramethylammonium hydroxide aqueous solution (TMAH aqueous solution) as a basic catalyst. . Into the dropping funnel, 15 ml of IPA and 12.69 g of 3-methacryloxypropyltrimethoxysilane (MTMS: SZ6300 manufactured by Toray Dow Corning Silicone Co., Ltd.) were added, and the IPMS solution of MTMS was stirred for 30 minutes at room temperature while stirring the reaction vessel. It was dripped over. After completion of the MTMS addition, the mixture was stirred for 2 hours without heating. After stirring for 2 hours, the solvent was removed under reduced pressure and dissolved in 50 ml of toluene. The reaction solution was washed with saturated brine until neutral, and then dehydrated with anhydrous magnesium sulfate. 8.6 g of hydrolysis product (silsesquioxane) was obtained by filtering off anhydrous magnesium sulfate and concentrating. This silsesquioxane was a colorless viscous liquid soluble in various organic solvents.

  Next, 20.65 g of the silsesquioxane obtained above, 82 ml of toluene, and 3.0 g of 10% TMAH aqueous solution are put into a reaction vessel equipped with a stirrer, a Din Stark, and a cooling tube, and heated gradually to obtain water. Was distilled off. Furthermore, it heated to 130 degreeC and recondensation reaction was performed for toluene at the reflux temperature. The temperature of the reaction solution at this time was 108 ° C. After stirring for 2 hours after refluxing toluene, the reaction was terminated. The reaction solution was washed with saturated brine until neutral, and then dehydrated with anhydrous magnesium sulfate. Anhydrous magnesium sulfate was filtered off and concentrated to obtain 18.77 g of a target silicone resin (mixture). The obtained silicone resin was a colorless viscous liquid soluble in various organic solvents.

Mass spectrometry after liquid chromatography separation of the cage silicone resin obtained by the recondensation reaction confirmed molecular ions with ammonium ions, and the composition ratio was T8: T10: T12: “Others”. It was about 2: 4: 1: 3, and it was confirmed that it was a silicone resin having a saddle type structure as a main component. T8, T10, and T12 are those in [RSiO _3/2 ] _n where n = 8, n = 10, and n = 12 (R is a methacryloyl group).

[Synthesis Example 4] (Preparation of urethane oligomer)
A method of obtaining polyurethane by reacting an organic isocyanate and a polyol was carried out as follows with reference to a known synthesis method (Japanese Patent Laid-Open No. 6-166737).

  The composition ratio of isophorone diisocyanate as an organic isocyanate and 2,2-dimethyl 1,3-propanediol, 1,4-cyclohexanedimethanol, and a polyol having a molar ratio of ε-caprolactone of 1: 1: 1 are 4: 3. The urethane acrylate oligomer 1 (number average molecular weight 3800) having an acrylic group at both ends, which is the target product, was obtained by reacting 2-hydroxyethyl acrylate.

[Example 1]
Linear silicone resin 1 (100 parts by weight) obtained in Synthesis Example 1, 1-hydroxycyclohexyl phenyl ketone (1 part by weight) as a photopolymerization initiator, and dicumyl peroxide (5 parts by weight) as a thermal polymerization initiator Part) to obtain a silicone resin composition.

Next, the silicone resin composition obtained above was cast (cast) on quartz glass having a thickness of 1 mm to a thickness of 0.1 mm using a bar coater, and an ultra-high pressure mercury lamp having 333 W / cm was obtained. Was cured at an integrated exposure amount of 2000 mJ / cm ² (in terms of 365 nm) to obtain a sheet-like resin molded body having a predetermined thickness. The reaction rate at this time was <2%. Table 1 shows the dose and the reaction rate together with the composition of the resin composition according to Example 1.

A small piece of 25 mm × 70 mm was cut out from the sheet-like resin molded body obtained above, and the temperature was 25 ° C. and the stretching speed was 5 mm / min. Using a biaxial stretching apparatus (manufactured by Imoto Seisakusho). The film was uniaxially stretched in the longitudinal direction under the above conditions to obtain a + 18% stretched film (stretched resin molded body). Next, the fixed jig was subjected to heat treatment at 200 ° C. for 1 hour using a small vacuum electric furnace (manufactured by Miwa Seisakusho), and then cooled to room temperature to obtain a + 14% stretched film (retardation film). The thickness of the stretched film is 133Myuemu, retardation values in a film plane _{Re = (n x -n y)} d was + 9 nm. Incidentally, n _x: x-axis direction of the refractive index, n _y: refractive index in the y-axis direction, d: film thickness, it is. Moreover, Re value (phase difference value) and the transmittance | permeability after the heat test (heat processing) which heat the obtained retardation film for 10 hours at 100 degreeC were measured. The results are shown in Table 2.

[Example 2]
A resin molded body was obtained in the same manner as in Example 1 except that the parts by weight and the integrated exposure amount of the composition shown in Table 1 were used.

  A small piece of 50 mm × 70 mm was cut out from the sheet-like resin molded body obtained above, and the temperature was 25 ° C. and the stretching speed was 5 mm / min. Using a biaxial stretching apparatus (manufactured by Imoto Seisakusho). The film was uniaxially stretched in the longitudinal direction under the above conditions to obtain a + 15% stretched film (stretched resin molded body).

Next, the cage silicone resin (30 parts by weight), dicyclopentanyl diacrylate (65 parts by weight), urethane acrylate oligomer (5 parts by weight) obtained in Synthesis Example 3 above, and 1-hydroxycyclohexyl as a photopolymerization initiator After a phenyl ketone (2.5 parts by weight) was mixed to obtain a resin composition for forming a resin layer, the + 15% stretched film obtained above was placed on quartz glass, and a bar coater was used on one side The resin composition for forming a resin layer was cast (cast) to a thickness of 50 μm, and cured using an ultrahigh pressure mercury lamp of 333 W / cm at an integrated exposure amount of 2000 mJ / cm ² (in terms of 365 nm). I let you. Further, the resin composition for forming a resin layer was cast on the remaining surface so as to have a thickness of 50 μm, and an integrated exposure dose of 3000 mJ / cm ² (using a 333 W / cm ultra-high pressure mercury lamp) The retardation film according to Example 2 having a resin layer was obtained by curing at 365 nm. The thickness of the retardation film is 200 [mu] m, the phase difference value in a film plane _{Re = (n x -n y)} d was + 34 nm. Moreover, Re value (phase difference value) and the transmittance | permeability after the heat test (heat processing) which heat the obtained retardation film for 10 hours at 100 degreeC were measured. The results are shown in Table 2.

[Comparative Example 1]
A resin molded body was obtained in the same manner as in Example 1 except that the resin composition was changed to parts by weight of the blending composition shown in Table 1 and the integrated exposure amount.

A small piece of 25 mm × 70 mm was cut out from the obtained resin molded body, and the temperature was 60 ° C., the stretching speed was 5 mm / min. The film was uniaxially stretched in the longitudinal direction under the conditions described above to obtain a + 10% stretched film. The fixed jig was subjected to heat treatment at 180 ° C. for 30 minutes using a hot air circulating oven (manufactured by Toyama Sangyo) to obtain a + 5% stretched film. The thickness of the stretched film is 224Myuemu, retardation values in a film plane _{Re = (n x -n y)} d was + 13 nm. However, when the heat resistance test was performed, the Re value (retardation value) became 0 nm, and the performance of the retardation film disappeared.

  Various tests and measurements in the above Examples and Comparative Examples were performed as follows.

(Heat resistance test)
It was kept at 100 ° C. for 10 hours using a TMA measuring apparatus EXSTAR6000 (manufactured by SII).

(Measurement of retardation value Re of retardation film)
It measured using phase difference measuring device NPDM-1000 (made by Nikon). Table 2 shows the phase difference value at λ550 nm.

(Measurement of retardation value Re change amount)
The difference in Re value after the heat resistance test was calculated from the Re value before the heat resistance test.

The abbreviations in Table 1 below are as follows.
A: Linear silicone resin 1
B: Linear silicone resin 2
C: vertical silicone resin D: dicyclopentanyl diacrylate (Kyoeisha Chemical Co., Ltd. light acrylate DCP-A)
E: Urethane acrylate oligomer F: 1-hydroxycyclohexyl phenyl ketone G: Dicumyl peroxide (Park Mill D, manufactured by NOF Corporation)

Claims (13)

(1) A resin composition comprising a silicone resin having a number average molecular weight of 1000 to 80000 represented by the following general formula (1), and (2) a photopolymerization initiator and / or (3) a thermal polymerization initiator. A retardation film, wherein the retardation film has a retardation value change amount in the range of 0 to 20 nm after heat treatment at 100 ° C. for 10 hours.

[Wherein X is a divalent group having at least one silicon atom and at least one aromatic group, R ₁ is an organic functional group having a (meth) acryloyl group, and R ₂ is (meth) acryloyl. An organic functional group having a group or a vinyl group, an aliphatic hydrocarbon having 1 to 25 carbon atoms, a substituted or unsubstituted cyclic aliphatic having 6 to 15 carbon atoms, or a substituted or unsubstituted ring having 6 to 15 carbon atoms Represents a formula aromatic, 1 = 1, m = 1-3, n is 2-290. ]   The retardation film according to claim 1, comprising (2) a photopolymerization initiator in a range of 0.1 to 3 parts by weight with respect to 100 parts by weight of the total resin composition.   The retardation film according to claim 1, comprising (3) a thermal polymerization initiator in a range of 0.1 to 10 parts by weight with respect to a total of 100 parts by weight of the resin composition.   While containing (2) a photopolymerization initiator in the range of 0.01 to 1 part by weight with respect to a total of 100 parts by weight of the resin composition, (3) a range of 0.01 to 10 parts by weight of the thermal polymerization initiator. The retardation film according to claim 1, which is contained in   The retardation film according to claim 1, wherein an in-plane retardation value at a wavelength of 550 nm at a thickness d = 250 μm after the heat test is 5 to 150 nm.   The retardation film according to any one of claims 1 to 5, comprising at least one resin layer made of light and / or thermosetting resin having a glass transition temperature Tg of 200 ° C or higher on at least one surface. (1) A resin composition comprising a silicone resin having a number average molecular weight of 1000 to 80000 represented by the following general formula (1), and (2) a photopolymerization initiator and / or (3) a thermal polymerization initiator. Is a method for producing a retardation film using

[Wherein X is a divalent group having at least one silicon atom and at least one aromatic group, R ₁ is an organic functional group having a (meth) acryloyl group, and R ₂ is (meth) acryloyl. An organic functional group having a group or a vinyl group, an aliphatic hydrocarbon having 1 to 25 carbon atoms, a substituted or unsubstituted cyclic aliphatic having 6 to 15 carbon atoms, or a substituted or unsubstituted ring having 6 to 15 carbon atoms Represents a formula aromatic, 1 = 1, m = 1-3, n is 2-290. ]
The resin composition is supported by at least one support, and after obtaining a resin molding by primary curing that reduces the unsaturated group of the component (1) by 0.1% to 50%, the resin molding is predetermined. In a state where the stretched resin molded body is fixed to the stretching jig, the stretched resin molded body is stretched in a range of 5 to 700% in a stretch ratio to obtain a stretched resin molded body. A method for producing a retardation film, wherein the film is secondarily cured by irradiation with heat and / or energy rays, and then cooled to room temperature.   The method for producing a retardation film according to claim 7, wherein the primary curing means is an energy ray irradiating means for irradiating 300 to 6000 mj of energy rays from the support side, the opposite side of the support, or both sides.   The method for producing a retardation film according to claim 7, wherein the primary curing means is a heating means for heating at 25 to 200 ° C.   The method for producing a retardation film according to claim 7, wherein the stretching means is uniaxial stretching orientation.   A curable resin containing a photopolymerization initiator is applied to at least one surface of a stretched resin molded body before secondary curing or a stretched resin molded body after secondary curing, and energy rays of 1000 to 20000 mj are irradiated. The method for producing a retardation film according to claim 7, wherein a photocurable resin layer is formed.   A curable resin containing a thermal polymerization initiator is applied to at least one surface of the stretched resin molded body before secondary curing or the stretched resin molded body after secondary curing, and a temperature of 25 to 200 ° C. for 20 minutes to The method for producing a retardation film according to claim 7, wherein the thermosetting resin layer is formed by a heat treatment for 4 hours.   A curable resin containing a photopolymerization initiator and a thermal polymerization initiator is applied to at least one surface of a stretched resin molded body before secondary curing or a stretched resin molded body after secondary curing, and an energy of 400 to 10,000 mj. The method for producing a retardation film according to claim 7, wherein the light and the thermosetting resin layer are formed by irradiation with a wire and a heat treatment at a temperature of 25 to 200 ° C. for 20 minutes to 4 hours.