JP2014052598A - Heat-resistant light-shielding sheet or film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-resistant light-shielding sheet or film which is excellent in heat resistance, dimensional stability and antistatic performance in spite of a monolayer structure without laminating a matte layer or a conductive layer, which has high light-shielding property and low reflectance and which is suitable for a shutter blade, a diaphragm or the like of an optical instrument.SOLUTION: The heat-resistant light-shielding sheet or film is formed by using a black resin composition comprising a polyamide imide resin, a conductive filler having a dibutyl phthalate oil absorption of 400 ml/100 g or more, and an inorganic powder having an average particle diameter of 1 to 10 μm. The content percentages of the conductive filler and of the inorganic powder are 3 to 8 wt.% and 8 to 29 wt.%, respectively.

Description

  The present invention relates to a heat-resistant light-shielding sheet or film having a single layer structure and having all the performances necessary for shutter blades and diaphragms of optical equipment.

  In recent years, many optical devices such as digital cameras and camera-equipped mobile phones are on the market, and further weight reduction, downsizing, and higher performance are demanded. Therefore, weight reduction, size reduction, and high performance are also required for members constituting them.

  A shutter blade for an optical device such as a digital camera has a role of blocking light from an image pickup device such as a CCD or a CMOS in a state where the shutter is closed. Further, in order to obtain a clearer image, the shutter speed is increased, and the shutter blade is required to be lightweight and highly slidable. Moreover, since the shutter blades are opened and closed by overlapping each other, there is a concern that the blades may stick together due to static electricity, and it is desirable that the shutter blades have an antistatic ability. Moreover, in order to suppress the generation of light leakage between the blades, the light must be efficiently absorbed so that the light is not reflected on the blade surface. Therefore, it is desired that the shutter blades are black and have a low surface reflectance.

  Since the shutter blades are required to have the above characteristics, light shielding films using various materials have been developed. For example, a light shielding material in which a hard carbon film is formed on the surface of a metal blade material such as an aluminum alloy has been proposed (see Patent Document 1). However, even if a hard carbon film is formed on the surface, sufficient low reflection characteristics cannot be realized, and generation of stray light due to reflected light cannot be avoided. In addition, since the metal material is heavy, when used as a shutter blade, the torque of the drive motor that drives the blade increases and the power consumption increases. There are other problems such as the shutter speed cannot be increased and noise is generated by contact between the blades.

  On the other hand, a light-shielding film formed of a resin film has also been proposed. For example, a film in which a light-shielding film containing a black pigment in a synthetic resin such as polyester or polycarbonate is roughened by a sandblasting method and a conductive layer is applied has been proposed (see Patent Document 2). However, the roughening of the surface by sandblasting has the problem that the unevenness of the surface is likely to be crushed due to film rubbing, etc., and the surface of the film tends to be glossy after long-term use in places where sliding is repeated, such as shutter blades. It was.

  Also proposed is a film in which a thermosetting resin layer containing carbon black, a lubricant and a matting agent is provided as a light shielding layer on both surfaces of a base film mainly composed of a thermoplastic resin (see Patent Document 3). ). However, since the heat resistance of the thermoplastic resin is not sufficient, there is a problem that the shutter blades overlapped with the heat-resistant light-shielding film are stuck (blocking) when exposed to high temperatures in summer for a long time. In recent years, mounting of camera modules and lens units has been desired to be performed in a reflow process for cost reduction, but there is a problem that reflow mounting cannot be performed due to insufficient heat resistance and dimensional stability. It was.

  In addition, with the miniaturization of digital cameras and mobile phones, there is an increasing demand for thin film for shutter blades, but the heat-resistant light-shielding film formed from the resin film has a laminated structure, so it is difficult to reduce the film thickness. There was a problem of becoming. Further, even when the film thickness is reduced, the content of the black pigment in the film is reduced, and there is a problem that the antistatic ability cannot be obtained in addition to sufficient light shielding properties.

  In addition, the polyamideimide resin composition containing the black pigment is applied to the base material of the mat film on which the surface irregularities are formed, and then the surface not grounded with the base material is pressed against the mat roll on which the surface irregularities are formed. Thus, a heat-resistant light-shielding film has been proposed in which irregularities are transferred and the front and back surfaces have a low reflectance (see Patent Documents 4 and 5). However, since the unevenness formed by the transfer of the mat film or roll is formed only on the surface, the film cross section cannot have a sufficiently low reflectance when used as a light-shielding blade, and there is a concern that the image quality is deteriorated due to stray light. Moreover, there is no description which examined antistatic ability.

  As described above, in the prior art, a heat-resistant light-shielding film having excellent heat resistance, dimensional stability, antistatic ability, high light-shielding property, and low reflectance has not been achieved. The heat resistance that can withstand the reflow process and the dimensional stability that suppresses warping are difficult to achieve with a general-purpose polyester resin such as polyethylene terephthalate (PET). In order to satisfy the antistatic ability, it is necessary to contain a conductive filler or form a conductive layer in the film, but the former uniformly disperses a large amount of conductive filler in the film so as to satisfy the antistatic ability. The latter has the problem that the thickness of the film increases. In order to satisfy low reflectivity, it is necessary to form irregularities on the surface and cause irregular reflection of light. However, in recent high-performance cameras, it is necessary to cause irregular reflection of light even at the film cross section. It cannot be satisfied only by forming a layer or applying it to a matte film.

Japanese Patent Laid-Open No. 2-116837 JP-A-1-120503 JP-A-9-274218 JP 2010-144146 A JP 2010-534342 A

  The present invention has been made to solve the problems of the prior art, and its purpose is to have a heat resistance, dimensional stability, charging, while having a single layer structure without a matte layer or a conductive layer. An object of the present invention is to provide a heat-resistant light-shielding sheet or film excellent in prevention ability, having high light-shielding properties and low reflectance, and suitable for shutter blades and diaphragms of optical equipment.

  As a result of intensive studies to achieve the above object, the present inventor contains a polyamideimide resin excellent in heat resistance and a conductive filler having a high dibutyl phthalate oil absorption amount and an inorganic powder having a specific particle size in a specific ratio. It is found that by using a black resin composition, a heat-resistant light-shielding film or sheet having excellent heat resistance, dimensional stability, antistatic ability, high light-shielding properties and low reflectance can be obtained, and the present invention is completed. It came.

式中、Ｒ^５及びＲ^６は同じであっても異なってもよく、それぞれ水素、または炭素数１〜４のアルキル基もしくはアルコキシ基を表す。
（６）ポリアミドイミド樹脂が、酸成分として、無水トリメリット酸、３，３′，４，４′−ベンゾフェノンテトラカルボン酸二無水物、および３，３′，４，４′−ビフェニルテトラカルボン酸二無水物を含み、イソシアネート成分として、ｏ−トリジンジイソシアネートを含むことを特徴とする（５）に記載の耐熱遮光シートまたはフィルム。
（７）耐熱遮光シートまたはフィルムの表面光沢度が３０以下であることを特徴とする（１）〜（６）のいずれかに記載の耐熱遮光シートまたはフィルム。
（８）耐熱遮光シートまたはフィルムの表面抵抗率が１０^１０Ω／□以下であることを特徴とする（１）〜（７）のいずれかに記載の耐熱遮光シートまたはフィルム。
（９）耐熱遮光シートまたはフィルムの厚みが１μｍ以上１００μｍ以下であることを特徴とする（１）〜（８）のいずれかに記載の耐熱遮光シートおよびフィルム。 That is, this invention has the structure of (1)-(9).
(1) A heat resistant light-shielding sheet or film formed using a polyamide resin, a conductive filler having a dibutyl phthalate oil absorption of 400 ml / 100 g or more, and a black resin composition containing an inorganic powder having an average particle diameter of 1 to 10 μm. The heat-resistant light-shielding sheet or film is characterized in that the conductive filler content is 3 to 8% by weight and the inorganic powder content is 8 to 29% by weight.
(2) The heat resistant light shielding sheet or film according to (1), wherein the inorganic powder is hydrophobic silica.
(3) The heat resistant light-shielding sheet or film according to (1) or (2), wherein the black resin composition further contains a conductive filler dispersant and / or an inorganic powder dispersant.
(4) The content of the conductive filler dispersant is 1 to 60 parts by weight with respect to 100 parts by weight of the conductive filler, and the content of the inorganic powder dispersant is 1 with respect to 100 parts by weight of the inorganic powder. The heat-resistant light-shielding sheet or film according to (3), which is ˜20 parts by weight.
(5) The heat-resistant light-shielding sheet or film according to any one of (1) to (4), wherein the polyamideimide resin contains the following general formula [I] as a repeating unit.

In the formula, R ⁵ and R ⁶ may be the same or different and each represents hydrogen, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group.
(6) Polyamideimide resin has trimellitic anhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, and 3,3 ′, 4,4′-biphenyltetracarboxylic acid as acid components The heat-resistant light-shielding sheet or film according to (5), comprising dianhydride and containing o-tolidine diisocyanate as an isocyanate component.
(7) The heat-resistant light-shielding sheet or film according to any one of (1) to (6), wherein the surface glossiness of the heat-resistant light-shielding sheet or film is 30 or less.
(8) The heat resistant light-shielding sheet or film according to any one of (1) to (7), wherein the surface resistivity of the heat-resistant light-shielding sheet or film is 10 ¹⁰ Ω / □ or less.
(9) The heat-resistant light-shielding sheet or film according to any one of (1) to (8), wherein the heat-resistant light-shielding sheet or film has a thickness of 1 μm to 100 μm.

  The heat-resistant light-shielding sheet or film of the present invention has a single-layer structure, is excellent in heat resistance, dimensional stability, antistatic ability, and can achieve high light-shielding properties and low reflectance. It can be used very suitably for diaphragming and the like.

  The heat-resistant light-shielding sheet or film of the present invention is formed using a black resin composition containing a polyamideimide resin, a conductive filler, and an inorganic powder as essential components.

  The black resin composition of the present invention comprises a polyamide-imide resin, a conductive filler, and an inorganic powder, and further a conductive filler dispersant, an inorganic powder dispersant, an organic solvent, paint shaker, stirrer, dissolver, etc. Can be prepared by using a proper combination of an emperor type disperser, a homogenizer, a ball mill, a sand mill, an AD mill, a bead mill, a three-roll mill and the like.

  The solution viscosity of the black resin composition is preferably 20 to 1000 dPa · s at 25 ° C., more preferably 40 to 500 dPa · s, and still more preferably 60 to 250 dPa · s. When the viscosity is out of the above range, coating defects such as thickness unevenness and coating stripes may occur, and productivity may be reduced. The black resin composition preferably has a total solid content concentration of 4 to 40% by weight, more preferably 5 to 30% by weight, such as polyamideimide resin, conductive filler, inorganic powder, and dispersant. When the solid content concentration is less than 4% by weight, the drying efficiency is poor and the cost is increased. On the other hand, when the solid content concentration exceeds 40% by weight, uniform dispersion of the filler becomes difficult.

  The water content of the black resin composition is preferably 5% by weight or less, more preferably 2% by weight or less. If the moisture content exceeds 5% by weight, the fillers may be aggregated and uniform dispersion may be difficult.

  Hereinafter, the polyamideimide resin, the conductive filler, the inorganic powder, the dispersant, and the organic solvent, which are main components of the black resin composition of the present invention, will be described in order.

  The polyamideimide resin used in the black resin composition of the present invention can be synthesized by a conventionally known method, for example, an isocyanate method, an amine method (for example, an acid chloride method, a low temperature solution polymerization method, a room temperature solution polymerization method, etc.). Etc. can be synthesized. The polyamide-imide resin needs to be soluble in an organic solvent. Therefore, it is preferable to synthesize the polyamide imide resin industrially by an isocyanate method in which a solution at the time of polymerization can be applied as it is.

  In the case of the isocyanate method, the polyamideimide resin can be synthesized by heat polycondensation of an acid component such as tricarboxylic acid anhydride, dicarboxylic acid, or tetracarboxylic acid anhydride with an isocyanate component in an organic solvent. Examples of the organic solvent include amides such as N-methyl-2-pyrrolidone, N, N′-dimethylacetamide, N, N′-dimethylformamide, tetramethylurea, and 1,3-dimethyl-2-imidazolidinone. Solvents, sulfur solvents such as dimethyl sulfoxide and sulfolane, ketone solvents such as cyclohexanone and methyl ethyl ketone, nitro solvents such as nitrobenzene and nitroethane, ether solvents such as diglyme and tetrahydrofuran, nitrile solvents such as acetonitrile and propionitrile And ester solvents such as γ-butyllactone and γ-valerolactone, which can be used alone or in combination.

（式［Ｉ］中、Ｒ^５およびＲ^６は同じであっても異なってもよく、それぞれ水素または炭素数１〜４のアルキル基もしくはアルコキシ基を示す。）

（式［ＩＩ］中、Ｒ^３およびＲ^４は同じであっても異なってもよく、それぞれ水素または炭素数１〜４のアルキル基もしくはアルコキシ基を示す。）

（式［ＩＩＩ］中、Ｒ^１およびＲ^２は同じであっても異なってもよく、それぞれ水素または炭素数１〜４のアルキル基もしくはアルコキシ基を示す。Ｙは直結（ビフェニル結合）またはエーテル結合（−Ｏ−）を示す。） As the polyamide-imide resin, a conventionally known resin can be used, preferably a polyamide-imide resin containing the following general formula [I] as a repeating unit, and more preferably the following general formula [I], general formula [II] is a polyamideimide resin containing the general formula [III] as a repeating unit.

(In the formula [I], R ⁵ and R ⁶ may be the same or different and each represents hydrogen or an alkyl group or alkoxy group having 1 to 4 carbon atoms.)

(In the formula [II], R ³ and R ⁴ may be the same or different and each represents hydrogen or an alkyl group or alkoxy group having 1 to 4 carbon atoms.)

(In the formula [III], R ¹ and R ² may be the same or different and each represents hydrogen or an alkyl group or alkoxy group having 1 to 4 carbon atoms. Y is a direct bond (biphenyl bond) or an ether bond. (-O-) is shown.)

  These copolymerization ratios are {general formula [I]} / {general formula [II]} / {general formula [III]} = 50 to 98/1 to 49/1 to 49 (mole% ratio). Is preferred. When the ratio of the general formula [I] is higher than the above upper limit and the ratios of the general formula [II] and the general formula [III] are lower than the lower limit, the heat resistance and dimensional stability tend to be lowered. Further, when the general formula [I] is not included or is included, the ratio is less than 50 mol%, and when the ratio of the general formula [II] and the general formula [III] is higher than the upper limit, the solubility in the organic solvent is poor. Thus, the dispersibility tends to be lowered. In addition, the reflectance and light shielding properties deteriorate, and the variation in the front and back surfaces and the thickness direction tends to increase.

  A more preferable copolymerization ratio of the polyamideimide resin containing the general formula [I], the general formula [II], and the general formula [III] as a repeating unit is {general formula [I]} / {general formula [II]} / { General formula [III]} = 60-90 / 5-35 / 5-30 (mol% ratio), {general formula [I]} / {general formula [II]} / {general formula [III]} = Most preferably, it is 65 to 85/10 to 30/5 to 20 (mole% ratio).

  For example, when a polyamide-imide resin containing the general formula [I], the general formula [II], and the general formula [III] as a repeating unit is synthesized by an isocyanate method, a particularly preferable combination of monomers used is di-substituted such as dimethyldiaminobiphenyl. The monomer having a biphenylene group is used, and trimellitic anhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, and 3,3 ′, 4,4 ′ are used as acid components. -When biphenyltetracarboxylic dianhydride is used and o-tolidine diisocyanate is used as the isocyanate component.

  The polyamide-imide resin is preferably one having a molecular weight corresponding to 0.3 to 2.8 dl / g in N-methyl-2-pyrrolidone (polymer concentration 0.5 g / dl) as a logarithmic viscosity at 30 ° C., More preferably, it has a molecular weight corresponding to 0.5 to 2.5 dl / g. If the logarithmic viscosity is less than 0.3 dl / g, mechanical properties may be insufficient when formed into a molded product such as a film, and if it exceeds 2.8 dl / g, the solution viscosity becomes high. Molding may be difficult. As a suitable solution viscosity of the polyamideimide resin, the solution viscosity at 25 ° C. is in the range of 20 to 1000 dPa · s. When the solution viscosity is out of the above range, the coatability may be lowered.

  The content ratio of the polyamideimide resin in the heat-resistant light-shielding sheet or film is preferably 58 to 89% by weight, more preferably 59 to 85% by weight. If the content ratio of the polyamideimide resin is less than 58% by weight, the mechanical properties may be insufficient. On the other hand, when the content ratio of the polyamideimide resin exceeds 89% by weight, the content ratio of various additives is decreased, and thus there is a possibility that the antistatic ability, the high light shielding property, and the low reflectance are insufficient.

  Examples of the conductive filler used in the black resin composition of the present invention include carbon black (acetylene black, channel black, furnace black, etc.), graphite (graphite), aniline black, titanium black, and the like. Black is most preferred. The carbon black has a dibutyl phthalate (DBP) oil absorption measured in accordance with JIS K6221 of 400 ml / 100 g or more, preferably 420 ml / 100 g or more, and more preferably 440 ml / 100 g or more. When the DBP oil absorption is less than the above lower limit, the structure size due to the filler aggregate is small, and it becomes difficult to form a conductive path expressed by the contact of the filler, which is not preferable for the expression of antistatic ability. Although an upper limit is not specifically limited, Actually, it is 600 ml / 100g. If it is too high, dispersion may be difficult. The content of the conductive filler in the heat-resistant light-shielding sheet or film is 3 to 8% by weight, preferably 3.2 to 7.0% by weight, and more preferably 3.3 to 3% from the viewpoint of developing the antistatic ability. 6.0% by weight. When the content of the conductive filler is less than 3% by weight, a sufficient conductive path may not be formed and the antistatic ability may not be exhibited. On the other hand, when the content is more than 8% by weight, the dispersibility is poor and it is difficult to form a uniform film, which is not preferable.

  As the inorganic powder used in the black resin composition of the present invention, silica, alumina, titanium oxide, magnesium oxide and the like can be used, and silica is most preferable. The inorganic powder preferably has an average particle diameter measured by a laser diffraction scattering method of 1 to 10 μm, more preferably 1 to 8 μm, and still more preferably 1 to 7 μm, from the viewpoint of low reflectance expression. If the particle size is smaller than the above range, sufficient surface irregularities may not be formed, and sufficient low reflectance may not be exhibited. Moreover, when larger than the said range, the fall of mechanical strength will be caused and it is unpreferable. The content of the inorganic powder in the heat-resistant light-shielding sheet or film is from 8 to 29% by weight, preferably from 9 to 28% by weight, and more preferably from 9 to 27% by weight, from the viewpoint of low reflectance. If the content of the inorganic powder is less than 8% by weight, surface unevenness may not be formed on the entire film, and sufficient low reflectance may not be exhibited. On the other hand, if it exceeds 29% by weight, the mechanical strength is lowered, which is not preferable. Even when the average viscosity of the inorganic powder in the sheet or film is measured with a scanning electron microscope (S2500, manufactured by Hitachi, Ltd.), the preferred average particle size range of the inorganic powder is when measured by a laser diffraction scattering method. It is the same.

  When silica is used as the inorganic powder, hydrophobic silica is preferred. By applying a hydrophobized surface treatment, the cohesive strength of silica is reduced, and the affinity with polyamide-imide resin is also improved, so that dispersibility is improved, high light-shielding properties and excellent low reflectance, Sheets and films with little variation in the thickness direction can be obtained. A method for hydrophobizing silica is known and can be performed, for example, by surface treatment with a silicone oil and / or a silane coupling agent. The silicone oil and silane coupling agent can be appropriately selected from conventionally known ones such as polydimethylsiloxane, amine-based silane coupling agent, and epoxy-based silane coupling agent.

  It is preferable to add a conductive filler dispersant to the black resin composition of the present invention. As the conductive filler dispersant, a known conductive filler dispersant may be used, and a dispersant made of a synthetic polymer is preferable. Specifically, when carbon black or graphite (graphite) is used as the conductive filler, BYK9077 (produced by Big Chemie Japan), BYK9076 (produced by Big Chemie Japan), which are carbon black dispersants, DISPERBYK2155 (manufactured by Big Chemie Japan Co., Ltd.), DISPERBYK145 (manufactured by Big Chemie Japan Co., Ltd.) and the like. ), DISPERBYK145 (Bicchemy Japan Co., Ltd.), DISPERBYK116 (Bicchemy Japan Co., Ltd.), and the like. The amount of the conductive filler dispersant added is preferably 1 to 60 parts by weight, more preferably 10 to 60 parts by weight, based on 100 parts by weight of the total amount of conductive filler in the black resin composition. If the addition amount is less than this range, it is difficult to uniformly disperse the conductive filler, or dispersion failure such as sedimentation and aggregation may occur over time, and dispersion stabilization may be difficult. On the other hand, if it exceeds this range, the heat resistance and mechanical properties of the film may be affected.

  It is preferable to add an inorganic powder dispersant to the black resin composition of the present invention. As the dispersant for the inorganic powder, a known dispersant for inorganic powder may be used, and a dispersant composed of a synthetic polymer is preferable. Specifically, when alumina, titanium oxide, magnesium oxide or the like is used as the inorganic powder, DISPERBYK2155, DISPERBYK116, DISPERBYK111, DISPERBYK180 (manufactured by Big Chemie Japan Co., Ltd.) and the like can be mentioned. In particular, when silica is used as the inorganic powder, DISPERBYK2008, DISPERBYK111 (manufactured by Big Chemie Japan Co., Ltd.) and the like can be mentioned. The amount of the inorganic powder dispersant added is preferably 1 to 20 parts by weight, more preferably 5 to 20 parts by weight, based on 100 parts by weight of the total amount of inorganic powder in the black resin composition. If the addition amount is less than this range, it is difficult to uniformly disperse the inorganic powder, or dispersion failure such as sedimentation and aggregation occurs with time, and dispersion stabilization may be difficult. On the other hand, if it exceeds this range, the heat resistance and mechanical properties of the film may be affected.

  The organic solvent used in the black resin composition of the present invention can be the same as the organic solvent exemplified by the polyamide-imide resin isocyanate method. That is, examples of the organic solvent used in the black resin composition include N-methyl-2-pyrrolidone, N, N′-dimethylacetamide, N, N′-dimethylformamide, tetramethylurea, and 1,3-dimethyl. Amide solvents such as -2-imidazolidinone, sulfur solvents such as dimethylsulfoxide and sulfolane, ketone solvents such as cyclohexanone and methyl ethyl ketone, nitro solvents such as nitrobenzene and nitroethane, ether solvents such as diglyme and tetrahydrofuran, Examples include nitrile solvents such as acetonitrile and propionitrile, and ester solvents such as γ-butyllactone and γ-valerolactone, and these can be used alone or in combination.

  The heat-resistant light-shielding sheet or film of the present invention is obtained by applying a black resin composition on a support such as an endless belt, a drum, or a carrier film, initially drying the coating film, peeling the film from the support, Manufactured by drying. As a coating method, a conventionally known method can be applied. For example, the coating can be performed by a roll coater, a knife coater, a doctor, a blade coater, a gravure coater, a die coater, a reverse coater, or the like.

  The drying conditions after application of the black resin composition are not particularly limited, but generally after initial drying at a temperature 70 to 130 ° C. lower than the boiling point (Tb (° C.)) of the organic solvent used in the black resin composition. Further, secondary drying is preferably performed at a temperature near or above the boiling point of the solvent. If the initial drying temperature is higher than the above range, foaming may occur on the coated surface, or unevenness of the residual solvent in the thickness direction of the resin layer will increase, so that the light-shielding film may be loosened. Moreover, when drying temperature is lower than the said range, drying time will become long and productivity will fall. The initial drying temperature varies depending on the type of solvent, but is generally 60 to 150 ° C, preferably 80 to 120 ° C. The time required for the initial drying is generally an effective time for the solvent remaining rate in the coating film to be 15 to 40% under the above temperature conditions, but generally 1 to 30 minutes. In particular 2-15 minutes.

  The secondary drying conditions are not particularly limited, and may be dried at a temperature near or above the boiling point of the solvent, but is generally 120 to 400 ° C, preferably 200 to 350 ° C. When the secondary drying temperature is low, the drying time becomes long and the productivity is lowered. If it is too high, the degradation reaction proceeds depending on the resin composition, the resin film may become brittle, and the cost also increases. The time required for the secondary drying is generally an effective time for the solvent remaining amount in the coating film to be 1% by weight or less under the above temperature conditions. It's time.

  The heat-resistant light-shielding sheet or film of the present invention preferably has a thickness of 1 μm or more and 100 μm or less, more preferably 80 μm or less, and even more preferably 40 μm or less. When the thickness exceeds 100 μm, not only the thickness and size are reduced, but also the shutter speed may be sacrificed. On the other hand, when the thickness is less than 1 μm, the handling properties and mechanical properties are not satisfactory, and in addition, pinholes are likely to occur during film formation.

  Since the heat-resistant light-shielding sheet or film of the present invention is produced as described above, it can have a glass transition temperature of 260 ° C. or higher, more preferably 280 ° C. or higher, further 300 ° C. or higher, particularly 320 ° C. or higher. It can have a transition temperature. Therefore, the heat-resistant light-shielding sheet or film of the present invention is excellent in heat resistance and is not likely to be deformed by heat during the reflow process.

  Since the heat-resistant light-shielding sheet or film of the present invention is produced as described above, it can have a linear expansion coefficient of 40 ppm / ° C. or less, further 35 ppm / ° C. or less, further 30 ppm / ° C. or less, particularly 25 ppm / ° C. It can have a coefficient of linear expansion of not more than ° C. Therefore, the heat-resistant light-shielding sheet or film of the present invention is excellent in dimensional stability, and there is no possibility of film peeling or warping.

Since the light-shielding film of the present invention is produced as described above, it can have a surface resistivity of 10 ¹⁰ Ω / □ or less, more preferably 10 ⁹ Ω / □ or less, further 10 ⁸ Ω / □ or less, In particular, it can have a surface resistivity of 10 ⁷ Ω / □ or less. Therefore, the heat resistant light shielding sheet or film of the present invention can achieve high antistatic ability. The lower limit of the surface resistivity is not particularly limited. In this specification, the unit “Ω / □” used for the surface resistivity is a unit equivalent to “Ω / sq.” (Ohms per square).

  Since the light-shielding film of the present invention is produced as described above, it can have a surface glossiness of 30 or less on both sides of the film. In particular, when the black resin composition is applied to the support and dried, the surface on the support side is the B surface, and when the opposite side is the A surface, the A surface can have a surface gloss of 15 or less, The surface gloss can be 29 or less on the B surface. Further, when the inorganic powder is added in an amount of 25 wt% to 29 wt%, both surfaces can have a surface glossiness of 15 or less, and the surface A can have a surface glossiness of 3 or less. Thus, since the heat-resistant light-shielding sheet or film of the present invention has a low reflectance, reflection of incident light can be sufficiently suppressed, and generation of leakage light between each blade can be effectively prevented. .

  As described above, the heat-resistant light-shielding sheet or film of the present invention is excellent in heat resistance, dimensional stability and antistatic ability, and satisfies high light-shielding properties and low reflectance. This is achieved by optimizing the polyamideimide resin skeleton, the kind / blending amount of the conductive filler, the kind / blending amount of the inorganic powder, etc. in the heat-resistant light-shielding sheet or film of the present invention. Moreover, the heat-resistant light-shielding sheet or film of the present invention achieves a reduction in variations in various characteristics even in the thickness direction by uniformly dispersing the conductive filler and inorganic powder in the sheet or film. This is a point greatly different from a sheet or film obtained by a conventional laminated structure or surface mat treatment.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these.

<Glass transition temperature>
Glass transition under the following conditions by the tensile load method using TMA (Thermomechanical analyzer / manufactured by Seiko Instruments Inc.) using the final dry film obtained in Examples and Comparative Examples as a sample. The temperature was measured. The higher the glass transition temperature, the higher the heat resistance. In Table 2, which will be described later, when the glass transition temperature could not be measured because film formation was impossible, “−” was indicated.
Load: 5g
Sample size: 4 mm (width) x 20 mm (length)
Temperature increase rate: 10 ° C / min Atmosphere: Nitrogen

<Linear expansion coefficient>
Using the films in the final dry state obtained in Examples and Comparative Examples as samples, linear expansion was performed under the following conditions by a tensile load method using TMA (Thermomechanical Analyzer / Seiko Instruments Co., Ltd.). The coefficient was measured. The linear expansion coefficient was calculated from the average value at 100 to 200 ° C. The lower the linear expansion coefficient, the higher the dimensional stability. In Table 2, which will be described later, when the linear expansion coefficient could not be measured because the film could not be formed, it was indicated as “−”.
Load: 5g
Sample size: 4 mm (width) x 20 mm (length)
Temperature increase rate: 10 ° C / min Atmosphere: Nitrogen

<Surface gloss>
The specular glossiness of the sample was measured according to JIS-Z8741-1997. The sample was irradiated with a light source at an incident angle of 60 °, and the intensity of the light reflected at a reflection angle of 60 ° was measured. The incident angle was 0 ° in the direction perpendicular to the light irradiation surface. As a measuring instrument, a VG200 gloss meter manufactured by Nippon Denshoku Co., Ltd. was used. The measurement was performed on both sides of the film (A side, B side), and the surface on the support side when the black resin composition was applied to the support and dried was designated as B side, and the opposite side was designated as A side. The lower the surface glossiness, the lower the reflectance. In Table 2, which will be described later, when the surface glossiness could not be measured because it was impossible to form a film, “-” was indicated.

<Light shielding>
A fluorescent lamp with a light source of 1000 lux was irradiated from a distance of 50 mm from the sample, and it was visually determined whether light was transmitted. The case where it did not transmit was marked as ◯, and the case where it passed was marked as x. In Table 2 to be described later, “−” was described when the light shielding property could not be measured because the film could not be formed.

<Surface resistivity>
The surface resistivity of the sample was measured under the following conditions using a resistivity meter (trade name “HIRESTA UP MCP-HT450 type”, manufactured by Mitsubishi Chemical Analytech Co., Ltd.). It is determined that the lower the surface resistivity, the higher the antistatic ability. In Table 2, which will be described later, when the surface resistivity could not be measured because film formation was impossible, “-” was indicated. In Table 2 described later, “<10 ⁴ ” is indicated when the measured value is less than 10 ⁴ Ω / □, and “> 10 ¹² ” is indicated when the measured value exceeds 10 ¹² Ω / □.
Probe: USR
Base: UFL
Applied voltage: 10V
Temperature: 22 ± 2 ° C
Humidity: 70 ± 5%
Measurement time: 1 minute

<Moisture content>
In accordance with the moisture measurement method for chemical products described in JIS-K0068-2, a black resin composition was used under the following conditions using a Karl Fischer moisture content measuring device (VA-100 manufactured by Mitsubishi Chemical Corporation). The moisture content of was measured.
Carrier gas: Nitrogen gas Flow rate: 240-300 ml / min Temperature: 240 ° C.

<Average particle size>
Methanol was used as a dispersion medium for the inorganic powder, and the average particle diameter of the inorganic powder was measured by a laser diffraction scattering method using a laser diffraction particle size distribution analyzer (SALD-2200, manufactured by Shimadzu Corporation).
<Average particle size of inorganic powder in sheet or film>
The inorganic powder in the sheet or film was observed with a scanning electron microscope (manufactured by Hitachi, Ltd., S2500), the magnification was appropriately changed according to the size of the inorganic powder, and the photographed photo was enlarged and copied. Next, the circumference of each inorganic powder was traced for at least 200 inorganic powders selected at random. The circle-equivalent diameter of the inorganic powder was measured from these trace images by an image analyzer, and the average value thereof was defined as the average particle diameter.

<Oil absorption amount>
It measured by the method based on JIS-K6217-4 (2001 fiscal year).

<Solution viscosity>
In accordance with the method for measuring the apparent viscosity with a rotational viscometer described in JIS-K7117-1, a black resin composition was used under the following conditions using a BH type viscometer (manufactured by Toki Sangyo Co., Ltd., type BHII). The solution viscosity of the product was measured.
Measurement temperature: 25 ° C
Rotor number: # 6
Rotation speed: 20rpm

<Logarithmic viscosity>
In accordance with the method for obtaining the viscosity of the polymer diluted solution described in JIS-K7367-1, the logarithmic viscosity of the resin was measured under the following conditions using an Ubbelohde viscometer.
Measurement temperature: 30 ° C
Solvent: N-methyl-2-pyrrolidone (25 ml)
Resin amount: 0.125 g

<Polyamideimide resin composition>
The polyamideimide resin composition was measured by the following method. A sample was prepared by dissolving 100 mg of polyamideimide resin in 0.6 ml of DMSO-d. The prepared sample was measured by ¹ H-NMR. For NMR, 400 MR manufactured by Varian was used.

Example 1
Trimellitic anhydride (80 mol% ratio), 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride (12.5 mol% ratio), 3,3', 4,4'-biphenyltetracarboxylic A polyamideimide resin synthesized from acid dianhydride (ratio by 7.5 mol%) and o-tolidine diisocyanate (ratio by 100 mol%) was dissolved in N-methyl-2-pyrrolidone so as to have a polymer concentration of 10% by weight. The composition of the obtained polyamideimide resin was measured by the above-described method. As a result, a repeating unit of a polymer of trimellitic anhydride and o-tolidine diisocyanate (corresponding to the general formula [I]), 3, 3 ′, 4, 4 A repeating unit of a polymer of '-benzophenonetetracarboxylic dianhydride and o-tolidine diisocyanate (corresponding to the general formula [II]), 3,3', 4,4'-biphenyltetracarboxylic dianhydride and o- The ratio (mole% ratio) of repeating units (corresponding to the general formula [III]) of the polymerized product by toridine diisocyanate was 80: 12.5: 7.5. The obtained polyamideimide resin had a logarithmic viscosity of 2.013 dl / g and a solution viscosity of 400 dPa · s.

1.00 g of the polyamide-imide resin solution, 1.00 g of carbon black (Ketjen Black ECP600JD: manufactured by Lion Corporation) having a DBP oil absorption of 495 ml / 100 g as a conductive filler, and hydrophobicity having an average particle size of 3.9 μm as an inorganic powder Silica (Silo Hovic 505: manufactured by Fuji Silysia Chemical Co., Ltd.) 7.14 g, carbon black dispersant (BYK9077: manufactured by Big Chemie Japan Co., Ltd.) 0.71 g, silica dispersant (DISPERBYK 2008: Big Chemie Japan Co., Ltd.) 1.07 g was diluted with 138.21 g of N-methyl-2-pyrrolidone so that the solid content concentration would be 7.00% by weight, and zirconia beads (specific gravity: 6.0 g / cm ³ , φ: 2.0 mm) ) 1 hour in a batch type tabletop sand mill (made by Hayashi Shoten Co., Ltd.) with 675 g Foremost dispersed, to prepare a master batch.

  The zirconia beads were separated from the master batch by filtration, blended with 77.06 g of the master batch, 146.06 g of the resin solution and 26.68 g of N-methyl-2-pyrrolidone so that the solid content concentration was 8.0%, and the dissolver Were uniformly dispersed for 10 minutes to prepare a black resin composition. The black resin composition thus obtained had a solution viscosity of 85 dPa · s and a moisture content of 0.300% by weight.

  The black resin composition was filtered through a 200-mesh nylon mesh filter, and then applied to a 100 μm-thick PET film (S10: manufactured by Toyo Cloth Co., Ltd.) using a knife coater, and initially dried at 90 ° C. for 8 minutes. Next, the film peeled from the PET film was secondarily dried by a hot air dryer under the conditions of 300 ° C. × 10 minutes. The solvent in the obtained film was completely removed, and the final completely dried film thickness was 25 μm.

  Tables 1 and 2 show the composition and evaluation results of the obtained films, respectively.

(Example 2)
A film was obtained in the same manner as in Example 1 except that the proportions of the conductive filler and inorganic powder contained in the film were finally changed to 3.3% by weight and 9% by weight, respectively. Tables 1 and 2 show the composition and evaluation results of the obtained films, respectively. The final completely dried film thickness was 25 μm. The black resin composition obtained in Example 2 had a solution viscosity of 80 dPa · s and a moisture content of 0.271% by weight.

(Example 3)
A film was obtained in the same manner as in Example 1 except that the proportions of the conductive filler and inorganic powder contained in the film were finally changed to 5.6 wt% and 25 wt%, respectively. Tables 1 and 2 show the composition and evaluation results of the obtained films, respectively. The final completely dried film thickness was 25 μm. The black resin composition obtained in Example 3 had a solution viscosity of 78 dPa · s and a moisture content of 0.244% by weight.

Example 4
A film was obtained in the same manner as in Example 1 except that the proportions of the conductive filler and inorganic powder contained in the film were finally changed to 6.0% by weight and 27% by weight, respectively. Tables 1 and 2 show the composition and evaluation results of the obtained films, respectively. The final completely dried film thickness was 25 μm. The black resin composition obtained in Example 4 had a solution viscosity of 73 dPa · s and a moisture content of 0.214% by weight.

(Example 5)
A film was obtained in the same manner as in Example 1 except that the average particle size of the hydrophobic silica used was changed to 1.3 μm (SS-50: manufactured by Tosoh Silica Co., Ltd.). Tables 1 and 2 show the composition and evaluation results of the obtained films, respectively. The final completely dried film thickness was 25 μm. The solution viscosity of the black resin composition obtained in Example 5 was 80 dPa · s, and the moisture content was 0.231 wt%.

(Example 6)
A film was obtained in the same manner as in Example 1 except that the average particle size of the hydrophobic silica used was changed to 6.7 μm (Silo Hovic 603: manufactured by Fuji Silysia Chemical Ltd.). Tables 1 and 2 show the composition and evaluation results of the obtained films, respectively. The final completely dried film thickness was 25 μm. The black resin composition obtained in Example 6 had a solution viscosity of 76 dPa · s and a moisture content of 0.156% by weight.

(Comparative Example 1)
A film was obtained in the same manner as in Example 1 except that the proportions of the conductive filler and inorganic powder contained in the film were finally changed to 2.5% by weight and 12% by weight, respectively. Tables 1 and 2 show the composition and evaluation results of the obtained films, respectively. The final completely dried film thickness was 25 μm. The black resin composition obtained in Comparative Example 1 had a solution viscosity of 79 dPa · s and a moisture content of 0.312% by weight.

(Comparative Example 2)
A film was obtained in the same manner as in Example 1 except that the proportions of the conductive filler and inorganic powder contained in the film were finally changed to 3.4 wt% and 7 wt%, respectively. Tables 1 and 2 show the composition and evaluation results of the obtained films, respectively. The final completely dried film thickness was 25 μm. The black resin composition obtained in Comparative Example 2 had a solution viscosity of 81 dPa · s and a moisture content of 0.325% by weight.

(Comparative Example 3)
Although an attempt was made to obtain a film in the same manner as in Example 1 except that the proportions of the conductive filler and inorganic powder contained in the film were finally changed to 5.1 wt% and 31 wt%, respectively. The film was broken during the drying process and could not be formed into a film. The composition and evaluation results of Comparative Example 3 are shown in Table 1 and Table 2, respectively. The black resin composition obtained in Comparative Example 3 had a solution viscosity of 76 dPa · s and a moisture content of 0.263 wt%.

(Comparative Example 4)
Although an attempt was made to obtain a film in the same manner as in Example 1 except that the proportions of the conductive filler and inorganic powder contained in the film were finally changed to 10.3 wt% and 14 wt%, respectively. Dispersibility was poor and a uniform film could not be formed. The composition and evaluation results of Comparative Example 4 are shown in Table 1 and Table 2, respectively. The black resin composition obtained in Comparative Example 4 had a solution viscosity of 73 dPa · s and a moisture content of 0.283 wt%.

(Comparative Example 5)
A film was obtained in the same manner as in Example 1 except that the carbon black used was changed to a DBP oil absorption of 360 ml / 100 g (Ketjen Black EC300J: manufactured by Lion Corporation). Tables 1 and 2 show the composition and evaluation results of the obtained films, respectively. The final completely dried film thickness was 25 μm. The black resin composition obtained in Comparative Example 5 had a solution viscosity of 74 dPa · s and a moisture content of 0.327% by weight.

(Comparative Example 6)
A film was obtained in the same manner as in Example 1 except that the average particle size of the hydrophobic silica used was changed to 100 nm (Snowtex ZL: manufactured by Nissan Chemical Industries, Ltd.). Tables 1 and 2 show the composition and evaluation results of the obtained films, respectively. The final completely dried film thickness was 25 μm. The black resin composition obtained in Comparative Example 6 had a solution viscosity of 74 dPa · s and a moisture content of 0.251% by weight.

(Comparative Example 7)
An attempt was made to obtain a film in the same manner as in Example 1 except that the resin solution used was changed to a polyester resin solution (RV200: manufactured by Toyobo Co., Ltd.), but the glass transition temperature of the resin (the glass transition temperature of the film). However, it was much lower than 300 ° C. (67 ° C.) and could not be formed into a film. The composition and evaluation results of Comparative Example 7 are shown in Table 1 and Table 2, respectively. The black resin composition obtained in Comparative Example 7 had a solution viscosity of 71 dPa · s and a moisture content of 0.346% by weight.

  As is clear from Tables 1 and 2, the films obtained in the examples are excellent in heat resistance, dimensional stability, and antistatic ability, and satisfy all of high light shielding properties and low reflectance. On the other hand, Comparative Example 1 with a small amount of conductive filler is inferior in antistatic ability, Comparative Example 2 with a small amount of inorganic powder is inferior in low reflectivity, and has a low DBP oil absorption amount of the conductive filler. 5 is inferior in antistatic ability, and Comparative Example 6 in which the average particle size of the inorganic powder is small is inferior in low reflectance. Moreover, the comparative example 3 with much content of inorganic powder, the comparative example 4 with much content of an electroconductive filler, and the comparative example 7 using a polyester resin were not able to be made into a film.

  Since the heat-resistant light-shielding sheet or film of the present invention is excellent in heat resistance, dimensional stability, antistatic ability, high light-shielding properties, and low reflectance, there is a great need for miniaturization, weight reduction, and high performance. "Aperture" and "Shutter blade" mounted on lens units of mobile phones, in-vehicle cameras, etc. "Aperture" of projectors, "Aperture blades" of aperture devices for adjusting light quantity, "Optical equipment parts", "Insulating substrates" It can be suitably used for an “antireflection layer”.

Claims (9)

  A heat-resistant light-shielding sheet or film formed using a polyamide resin, a conductive filler having a dibutyl phthalate oil absorption of 400 ml / 100 g or more, and a black resin composition containing an inorganic powder having an average particle size of 1 to 10 μm. A heat-resistant light-shielding sheet or film, wherein the content of the conductive filler is 3 to 8% by weight and the content of the inorganic powder is 8 to 29% by weight.   The heat-resistant light-shielding sheet or film according to claim 1, wherein the inorganic powder is hydrophobic silica.   The heat resistant light-shielding sheet or film according to claim 1 or 2, wherein the black resin composition further contains a conductive filler dispersant and / or an inorganic powder dispersant.   The content of the conductive filler dispersant is 1 to 60 parts by weight with respect to 100 parts by weight of the conductive filler, and the content of the inorganic powder dispersant is 1 to 20 parts by weight with respect to 100 parts by weight of the inorganic powder. It is a part, The heat-resistant light-shielding sheet or film of Claim 3 characterized by the above-mentioned. The heat resistant light-shielding sheet or film according to claim 1, wherein the polyamideimide resin contains the following general formula [I] as a repeating unit.

In the formula, R ⁵ and R ⁶ may be the same or different and each represents hydrogen, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group.   Polyamideimide resin has trimellitic anhydride, 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride, and 3,3', 4,4'-biphenyltetracarboxylic dianhydride as acid components The heat-resistant light-shielding sheet or film according to claim 5, comprising o-tolidine diisocyanate as an isocyanate component.   The heat-resistant light-shielding sheet or film according to any one of claims 1 to 6, wherein the surface glossiness of the heat-resistant light-shielding sheet or film is 30 or less. The heat resistant light shielding sheet or film according to claim 1, wherein the heat resistant light shielding sheet or film has a surface resistivity of 10 ¹⁰ Ω / □ or less.   The heat-resistant light-shielding sheet or film according to any one of claims 1 to 8, wherein the heat-resistant light-shielding sheet or film has a thickness of 1 µm to 100 µm.