JP2013057948A - Reflective light-shielding structure, method for manufacturing reflective light-shielding structure, and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflective light-shielding structure, which is excellent in reflecting and light-shielding properties for light of a backlight when the structure is used between a liquid crystal display module unit and a backlight unit, thereby, which can improve visibility of a liquid crystal display and reduce power consumption, which has excellent shock resistance and which hardly induces 'blur' by pressing when the display module is used as a touch panel.SOLUTION: A reflective light-shielding structure 2 is an adhesive tape or sheet, which includes a light-shielding layer comprising a black foamed material and a white or silver-color reflective layer and has an adhesive layer having a thickness of 2 to 100 μm on at least one surface. The light-shielding layer has a thickness of 0.1 to 1.5 mm, in which the black foamed material has an average cell diameter of 30 to 250 μm and a density of 0.01 to 0.2 g/cm. The reflective layer is a metal vapor deposition layer.

Description

  The present invention relates to a structure having reflectivity and light shielding properties, a method for manufacturing the structure, and a liquid crystal display device including the structure.

  Conventionally, in a liquid crystal display device such as a touch panel or a cellular phone, a white or silver reflective layer (backlight side) and a black light-shielding layer (liquid crystal) are disposed between a liquid crystal display module unit and a backlight unit related to a display screen. A reflective member (see Patent Document 1) having a display module side) or an adhesive tape or sheet ("tape or sheet" may be simply referred to as "tape" or "sheet") is used (Patent Documents 2 and 2). 15). The reflective layer reflects the light of the backlight, thereby exhibiting the effect of improving the luminance and reducing the power consumption by using the light efficiently. On the other hand, the light shielding layer prevents the backlight from leaking to the liquid crystal display module side, and exhibits the effect of improving the visibility.

  In recent years, however, these liquid crystal display devices have been demanded to have higher functions, and particularly in touch panel applications, it has been required to reduce bleeding of the liquid crystal display surface due to pressing with a finger. Further, in mobile phone applications, along with further miniaturization and weight reduction, it has been required to exhibit high impact resistance even without a protective plate such as an acrylic plate. From this point of view, further improvement of the physical properties of the conventional liquid crystal display device is required at present.

  In recent years, as the cellular phone is further reduced in thickness and the liquid crystal display screen is increased in size, the space for mounting the member is reduced, and the line width of the reflection light shielding member, the adhesive tape, or the sheet needs to be narrowed. Further, when the reflective light shielding member is mounted, a minute step is generated due to a reduction in space. However, the conventional reflective / light-shielding member as described above has a disadvantage in that the adhesive strength is significantly reduced as the line width is narrowed when the member is attached to a member having a minute step, and the adhesive reliability is reduced.

JP-A-11-149254 JP 2005-213282 A JP 2004-59723 A JP 2002-235053 A JP 2002-350612 A JP 2004-161955 A JP 2004-184443 A JP 2004-2331736 A JP 2004-231737 A JP 2004-156015 A JP 2004-244499 A Japanese Patent Laid-Open No. 2002-249741 JP 2004-53759 A JP 2002-23663 A JP 2006-10931 A

  Accordingly, an object of the present invention is to provide a liquid crystal display that has excellent reflectivity and light shielding properties, and at the same time, can reduce blur due to pressing, and further has a drop impact resistance and adhesion reliability that can follow a minute step. An object is to provide a reflection / light-shielding structure used between a module unit and a backlight unit, and a liquid crystal display device using the reflection / light-shielding structure.

  As a result of intensive studies to achieve the above object, the present inventors have used a black resin foam as a light-shielding layer as a reflective light-shielding structure suitably used between a liquid crystal display module unit and a backlight unit. Furthermore, by using a reflection / light-shielding structure provided with a white or silver reflective layer, an appropriate cushioning property is obtained, so that bleeding of the liquid crystal display surface due to pressing is improved, and drop impact resistance and minute The present inventors have found that adhesion reliability that can follow a step can be improved, and the present invention has been completed.

That is, the present invention has a light-shielding layer made of a black foam and a white or silver reflective layer, the light-shielding layer has a thickness of 0.1 to 1.5 mm, and the average cell of the black foam The diameter is 30 to 250 μm, the density of the black foam is 0.01 to 0.2 g / cm ³ , and the reflective layer is a metal vapor deposition layer,
Provided is a reflective / light-shielding structure characterized by being an adhesive tape or sheet having an adhesive layer having a thickness of 2 to 100 μm on at least one surface.

  The reflection / light-shielding structure has at least an elongated tape-shaped portion, and the width of the tape-shaped portion is preferably 0.5 to 10 mm.

  The black foam is preferably a black polyolefin resin foam obtained by foaming a polyolefin resin composition using a high-pressure inert gas.

  The polyolefin-based resin composition preferably contains 1 to 30% by weight of the colorant based on the entire resin composition.

  The inert gas is preferably carbon dioxide or nitrogen.

  The inert gas is preferably in a supercritical state.

  The reflective layer is preferably a white polyester film.

  In the reflection light-shielding structure, it is preferable that the black foam contains a flame retardant, and the black foam has flame retardancy.

  In the reflection / light-shielding structure, the entire reflection / light-shielding structure preferably has flame retardancy.

  The pressure-sensitive adhesive layer is preferably an acrylic pressure-sensitive adhesive layer.

  Furthermore, the present invention is a method for producing the reflection / light-shielding structure, wherein a foamable resin composition containing a colorant is impregnated with an inert gas, and then bubbles are formed by releasing the pressure. A method for producing a reflective light-shielding structure is provided, in which a light-shielding layer made of a black foam and a white or silver reflective layer are laminated to obtain a reflective light-shielding structure.

  Furthermore, the present invention provides a liquid crystal display module unit, a backlight unit, and a liquid crystal display device having the above-described reflection / light-shielding structure, wherein the reflection / light-shielding structure is located between the liquid crystal display module unit and the backlight unit. A liquid crystal display device is provided.

  According to the reflective / light-shielding structure of the present invention, since it has the above-described configuration, when used in applications such as a touch panel, the liquid crystal display surface is less likely to bleed due to the pressing of a finger and has excellent drop impact resistance. Can be demonstrated.

  The reflective / light-shielding structure (reflective / light-shielding member) of the present invention has at least a light-shielding layer and a reflective layer. The reflective light-shielding structure has an adhesive structure (reflective light-shielding pressure-sensitive adhesive tape or sheet) having an adhesive layer on at least one surface (outermost surface), or an adhesive structure (reflection) having an adhesive layer on both outermost surfaces. It may be a light-shielding double-sided pressure-sensitive adhesive tape or sheet). In the case of a reflective / light-shielding pressure-sensitive adhesive tape or sheet (including a reflective / light-shielding double-sided pressure-sensitive adhesive tape or sheet), a release film is further stuck on the pressure-sensitive adhesive layer from the viewpoint of protecting the pressure-sensitive adhesive layer and improving workability. May be. The reflective / light-shielding structure without the pressure-sensitive adhesive layer has an advantage in that the reworkability is high, while the reflective / light-shielding adhesive tape has an advantage that the assembly process can be simplified.

[Light-shielding layer]
The light shielding layer in the reflective light shielding structure of the present invention is made of a black foam. In the present invention, the black and basically, L ^* a ^* b ^* L defined by the color system ^* is 50 or less (0 to 50) [preferably 47 or less (0 to 47), more preferably Means a black color of 45 or less (0 to 45)]. Note that a ^* and b ^* defined by the L ^* a ^* b ^* color system can be appropriately selected according to the value of L ^* . As a ^* and b ^* , for example, both are preferably in the range of −10 to 10 (particularly −5 to 5), and in particular, both are 0 or almost 0 (range of −2 to 2). It is preferable that

In the present invention, a color difference meter (trade name “CR-200” manufactured by Minolta Co .; color difference meter) is used for L ^* , a ^* , and b ^* defined in the L ^* a ^* b ^* color system. It is obtained by measuring. The L ^* a ^* b ^* color system is a color space recommended by the International Commission on Illumination (CIE) in 1976, and is a color space called the CIE 1976 (L ^* a ^* b ^* ) color system. It means that. The L ^* a ^* b ^* color system is defined in JIS Z 8729 in the Japanese Industrial Standard.

  The foam used in the light-shielding layer of the present invention can be a known and commonly used resin foam, and is not particularly limited, but from the viewpoint of being less susceptible to degradation due to hydrolysis compared to polyethylene terephthalate and the like. A polyolefin resin foam is preferable. The polyolefin resin foam may be a resin foam formed from a resin composition containing only a polyolefin resin such as polyethylene or polypropylene as a resin component, but from the viewpoint of cushioning properties, flexibility, high expansion ratio, etc. A foam formed from a resin composition comprising a mixture of a polyolefin-based resin and rubber or thermoplastic elastomer is preferred.

  As the polyolefin resin used in the resin foam of the present invention, for example, an α-olefin crystalline thermoplastic resin and / or an α-olefin amorphous thermoplastic resin can be used. These may be used alone or in combination of two or more, and may be used in combination of crystalline and amorphous resins.

  The α-olefin-based crystalline thermoplastic resin is not particularly limited as long as it is a crystalline resin having an α-olefin as a main monomer component, and even if it is a homopolymer of α-olefin, α-olefin and other It may be a copolymer with a monomer. Moreover, the mixture of 2 or more types of these different polymers and / or copolymers may be sufficient. The α-olefin-based crystalline thermoplastic resin preferably contains 80 mol% or more (more preferably 90 mol% or more) of α-olefin with respect to the entire monomer structural unit. Examples of the α-olefin include ethylene, propene (propylene), 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 3-methyl-1-pentene, and 4-methyl-1- Examples thereof include α-olefins having 2 to 12 carbon atoms such as pentene, 3-ethyl-1-pentene, 1-octene, 1-decene and 1-undecene. These can be used alone or in combination of two or more.

  When the α-olefin-based crystalline thermoplastic resin is a copolymer, the copolymer may be either a random copolymer or a block copolymer. However, in order to have crystallinity, in the random copolymer, the total content of the structural units excluding the α-olefin is 15 mol% or less (more preferably 10% when the entire random copolymer is 100 mol%). Mol% or less). In the block copolymer, the total content of structural units excluding the α-olefin is preferably 40 mol% or less (more preferably 20 mol% or less) when the block copolymer is 100 mol%. .

  On the other hand, the α-olefin-based amorphous thermoplastic resin is not particularly limited as long as it is an amorphous resin having an α-olefin as a main monomer component. A copolymer of an olefin and another monomer may be used. Moreover, the mixture of these 2 or more types of different polymers and / or copolymers may be sufficient. The α-olefin-based amorphous thermoplastic resin preferably contains 50 mol% or more (more preferably 60 mol% or more) of α-olefin with respect to the entire monomer structural unit. As the α-olefin, an α-olefin having 3 or more carbon atoms is preferably used, and the same α-olefin having 3 to 12 carbon atoms as exemplified in the α-olefin-based crystalline thermoplastic resin is used. preferable.

  Examples of the α-olefin-based amorphous thermoplastic resin include homopolymers such as atactic polypropylene and atactic poly-1-butene, propylene (containing 50 mol% or more) and other α-olefins (ethylene, 1- Copolymers with butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, etc.), 1-butene (containing 50 mol% or more) and other α-olefins ( And copolymers thereof with ethylene, propylene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, and the like. The copolymer may be either a random copolymer or a block copolymer. However, in the case of a block polymer, the α-olefin unit as a main component (propylene and 1-butene in the copolymer) needs to be bonded with an atactic structure. Further, when the α-olefin-based amorphous thermoplastic resin is a copolymer of an α-olefin having 3 or more carbon atoms and ethylene, assuming that the entire copolymer is 100 mol%, the α-olefin content is 50% mol or more (more preferably 60 to 100 mol%).

  The melt tension of the polyolefin resin at a temperature of 210 ° C. and a take-off speed of 2.0 m / min is not particularly limited, but is preferably 3.0 cN or more (for example, about 3.0 to 50 cN), more preferably 5. It is 0 cN or more (for example, about 5.0 to 50 cN), more preferably 8.0 cN or more (for example, about 8.0 to 50 cN). When the melt tension is less than 3.0 cN, when the polyolefin resin composition is foamed, the expansion ratio is low, independent bubbles are not easily formed, and the shape of the formed bubbles is difficult to be uniform. Become. Therefore, in order to obtain a foam having a high expansion ratio, a high closed cell property, and a uniform foam cell shape, the melt tension is preferably 3.0 cN or more.

  The amount of the polyolefin resin of the present invention is preferably 10 to 200 parts by weight, more preferably 20 to 100 parts by weight, based on 100 parts by weight of the rubber / thermoplastic elastomer component described later. When the amount of the polyolefin resin used is less than 10 parts by weight relative to 100 parts by weight of the rubber / thermoplastic elastomer component, it is difficult to obtain a foam with a high expansion ratio because gas easily escapes during foaming. If it exceeds 200 parts by weight, the cushioning property tends to deteriorate.

  Examples of the rubber / thermoplastic elastomer used in the resin foam of the present invention include natural rubber, butadiene rubber, polyisobutylene, isoprene rubber, chloroprene rubber, butyl rubber, nitrile butyl rubber, ethylene-propylene copolymer, ethylene-propylene- Olefin elastomer such as diene copolymer, ethylene-vinyl acetate copolymer, polybutene, chlorinated polyethylene; styrene-butadiene-styrene copolymer, styrene-isoprene-styrene copolymer, styrene-isoprene-butadiene-styrene copolymer Examples thereof include styrenic elastomers such as polymers and their hydrogenated polymers; thermoplastic polyester elastomers; thermoplastic polyurethane elastomers; thermoplastic acrylic elastomers. These rubbers and thermoplastic polymers can be used alone or in admixture of two or more.

  A colorant is added to the resin composition used for the light-shielding layer of the present invention for the purpose of imparting light-shielding properties. The colorant to be added may be any colorant (colorant) such as a pigment or a dye, but the pigment can be suitably used and is not particularly limited, but a black pigment is preferred. The black pigment that can be used in the present invention is preferably a pigment that has high compatibility with the resin composition and does not affect the foaming characteristics. For example, carbon black (furnace black, channel black, acetylene black, thermal black, lamp black, etc. ), Graphite, copper oxide, manganese dioxide, aniline black, perylene black, titanium black, cyanine black, activated carbon, ferrite (nonmagnetic ferrite, magnetic ferrite, etc.), magnetite, chromium oxide, iron oxide, molybdenum disulfide, chromium complex, Examples thereof include complex oxide black pigments and anthraquinone organic black pigments. These black color materials can be used alone or in combination of two or more.

  Among the above, carbon black is preferable as the black pigment used in the light-shielding layer of the present invention. Carbon black having an average secondary particle size of 2 μm or less is preferable.

The amount of the coloring ^{agent, L * a * b * L} * is defined by a color system, is not particularly limited as long as it is capable of forming a blackish color of foam to be 50 or less (0 to 50) Is, for example, about 1 to 30% by weight (preferably about 2 to 20% by weight) of the entire resin foam.

  When flame retardancy is required for the reflective light-shielding structure or light-shielding layer of the present invention, it is preferable to add a flame retardant to the resin composition used for the light-shielding layer. As the flame retardant, known and commonly used flame retardants used for polyolefin resins and the like can be used, and although not particularly limited, metal hydroxides are preferably used.

  Examples of the metal element in the metal hydroxide include aluminum (Al), magnesium (Mg), calcium (Ca), nickel (Ni), cobalt (Co), tin (Sn), zinc (Zn), and copper (Cu). , Iron (Fe), titanium (Ti), boron (B) and the like. Of these, aluminum, magnesium and the like are preferable. The metal hydroxide may be composed of one kind of metal element or may be composed of two or more kinds of metal elements. In the present invention, as the metal hydroxide composed of one kind of metal element, for example, aluminum hydroxide, magnesium hydroxide or the like is preferably used.

As the metal hydroxide, a composite metal hydroxide that is a metal hydroxide composed of two or more metal elements can also be suitably used. Specific examples of such composite metal hydroxides include sMgO. (1-s) NiO.cH ₂ O [0 <s <1, 0 <c ≦ 1], sMgO. (1-s ) ZnO.cH ₂ O [0 <s <1, 0 <c ≦ 1], sA1 ₂ O _3. (1-s) Fe ₂ O ₃ .cH ₂ O [0 <s <1, 0 <c ≦ 3 ] Etc. are mentioned. Among these, a composite metal hydroxide composed of magnesium, nickel, and zinc is optimal. Specifically, a composite represented by sMgO. (1-s) Q ¹ O.cH ₂ O [Q ¹ represents Ni or Zn, and 0 <s <1, 0 <c ≦ 1]. Metal hydroxides, for example, magnesium oxide / nickel oxide hydrate and magnesium oxide / zinc oxide hydrate are particularly preferably used. The composite metal hydroxide may have a polyhedral shape or a thin flat plate shape. When a polyhedral composite metal hydroxide is used, a highly foamed resin foam can be obtained.

  The average particle diameter (average particle diameter) of the metal hydroxide is, for example, about 0.5 to 10 μm, preferably about 0.6 to 6 μm. The average particle size can be measured by, for example, a laser particle size measuring device. When the average particle size exceeds 10 μm, it becomes difficult to obtain a highly foamed resin foam. The content of the metal hydroxide is, for example, about 5 to 90% by weight, preferably about 7 to 70% by weight of the entire resin foam. If the content is too small, the flame retarding effect is reduced, while if the content is too large, it is difficult to obtain a highly foamed resin foam.

  Furthermore, the metal hydroxide may be surface-treated. As the surface treatment method, a surface treatment method using a surface treatment agent conventionally used for metal hydroxides can be employed. Examples of the surface treatment agent include aluminum compounds (aluminum coupling agents), silane compounds (silane coupling agents), titanate compounds (titanate coupling agents), epoxy compounds, isocyanate compounds, and higher grades. Fatty acids or salts thereof and phosphate esters are preferably used. A surface treating agent can be used individually or in mixture of 2 or more types.

  Among the surface treatment agents, aluminum compounds (such as aluminum coupling agents) and titanate compounds (such as titanate coupling agents) are preferable.

  The usage-amount of a surface treating agent can be selected from the range of about 0.1-10 weight part (preferably 0.3-8 weight part) with respect to 100 weight part of metal hydroxides, for example. As a surface treatment method for the metal hydroxide, a conventional surface treatment method (for example, a dry method, a wet method, an integral blend method, etc.) can be appropriately selected and applied. The surface-treated metal hydroxide can be used alone or in combination of two or more.

  In such a surface-treated metal hydroxide, since the surface of the metal hydroxide is covered with an organic group or the like, flame retardancy due to the metal hydroxide is suppressed or prevented while preventing a decrease in the fluidity of the resin. It is thought that the effect of crystallization can be demonstrated.

  Further, flame retardants include bromine compounds such as pentabromodiphenyl ether, octabromodiphenyl ether, decabromodiphenyl ether, tetrabromobisphenol A, hexabromocyclododecane, chlorine compounds such as chlorinated paraffin compounds, and phosphate esters such as triphenyl phosphate. It is also possible to use phosphorus compounds such as red phosphorus and the like.

  In addition to the above, the resin composition used for the foam of the light-shielding layer of the present invention can contain various additives as necessary. Examples of such additives include lubricants, nucleating agents, foam stabilizers, anti-aging agents, heat stabilizers, light stabilizers such as HALS, weathering agents, metal deactivators, ultraviolet absorbers, light stabilizers, copper Stabilizers such as harmful agents, antibacterial agents, fungicides, dispersants, plasticizers, tackifiers, fillers and the like can be mentioned.

  The resin composition used for the foam of the light-shielding layer of the present invention can be prepared by using a conventional melt-kneading apparatus such as an open type mixing roll, a non-open type Banbury mixer, a single screw extruder, a twin screw extruder, a continuous type. It can be carried out using a type kneader, a pressure kneader or the like.

  The foam used for the light-shielding layer of the present invention is obtained by foaming the above resin composition. As a manufacturing method of a foam, the method normally used for foam molding, such as a physical method and a chemical method, is employable. Examples of the physical method include a method of forming bubbles by dispersing a low boiling point liquid (foaming agent) such as chlorofluorocarbons or hydrocarbons in a polymer, and then heating to volatilize the foaming agent. . Moreover, as a chemical method, the method etc. which form a cell with the gas produced | generated by the thermal decomposition of the compound (foaming agent) added to the polymer base, and obtain a foam are mentioned.

  Among these, as a method for producing a foam, since a foam having a small cell diameter and a high cell density can be obtained, a method using a high-pressure inert gas as a foaming agent, for example, in a resin such as a polyolefin resin, etc. Furthermore, after impregnating with a high-pressure inert gas, a method of forming bubbles by forming a bubble through a step of releasing pressure (for example, a step of reducing pressure, etc.) is preferable. In particular, when carbon dioxide is used as a foaming agent, a clean foam with less impurities is produced with less environmental impact, no outgassing, and no contamination of liquid crystal display members even when used inside the liquid crystal display device. From the viewpoint of being able to In the foaming method based on the physical method as described above, there is a concern about the impact on the environment such as the flammability and toxicity of the substance used as the foaming agent and the destruction of the ozone layer. In addition, in the foaming method based on the chemical method, the residue of the foaming gas remains in the foam, so that the contamination by the corrosive gas or impurities in the gas is a problem particularly in the electronic device application where the demand for low pollution is high. Become. In both of these physical foaming methods and chemical foaming methods, it is difficult to form a fine bubble structure, and it is particularly difficult to form fine bubbles of 300 μm or less.

  Thus, in the present invention, as a method for producing a foam, a production method using a method using a high-pressure inert gas as a foaming agent is suitable. As described above, a high-pressure inert gas is added to the resin composition. After impregnating the gas, a method of forming a foam through a step of releasing the pressure (for example, a step of reducing the pressure) can be suitably employed. In addition, when impregnating with the inert gas, the pre-molded unfoamed molded product may be impregnated with the inert gas, or the molten resin composition is impregnated with the inert gas under pressure. Also good. Therefore, specifically, as a method for producing a foam, for example, a resin composition is impregnated with a high-pressure inert gas and then subjected to a step of releasing pressure (for example, a step of reducing pressure, etc.). Method, a method in which an unfoamed molded article made of resin is impregnated with a high-pressure inert gas and then released through a step of releasing pressure (for example, a step of reducing pressure, etc.), or inert to a molten resin composition A method in which the gas is impregnated under pressure and then subjected to molding with reduced pressure is preferred.

  The inert gas is not particularly limited as long as it is inert to the resin composition of the present invention and can be impregnated, and examples thereof include carbon dioxide, nitrogen gas, and air. These gases may be mixed and used. Among these, carbon dioxide having a large impregnation amount into the resin composition used as the material of the foam and having a high impregnation rate is preferable.

  The inert gas when impregnating the resin composition is preferably in a supercritical state. In the supercritical state, the solubility of the gas in the thermoplastic polymer is increased, and a high concentration can be mixed. Further, when the pressure drops rapidly after impregnation, since the concentration is high as described above, the generation of bubble nuclei increases, and even if the density of bubbles formed by the growth of the bubble nuclei is the same as the porosity, it is large. Therefore, fine bubbles can be obtained. Carbon dioxide has a critical temperature of 31 ° C. and a critical pressure of 7.4 MPa.

  Production of the foam used for the light-shielding layer of the present invention is not particularly limited as long as it is a method that can be foam-molded using the resin composition, and may be performed by any method such as a batch method or a continuous method. The continuous system is particularly preferred from the viewpoint that the amount of the foaming agent (inert gas or the like) dissolved in the resin composition can be appropriately controlled and a preferable foam can be easily obtained.

  The example which manufactures a resin foam by a batch system is shown below. First, the resin composition is extruded by using an extruder such as a single screw extruder or a twin screw extruder, or the resin composition is provided with blades such as a roller, a cam, a kneader, and a Banbury type. A foam-molding resin sheet is produced by uniformly kneading using a kneader and pressing to a predetermined thickness using a hot plate press or the like. The foam molding resin sheet (unfoamed sheet) thus obtained is placed in a high-pressure container, and a high-pressure inert gas (for example, supercritical carbon dioxide) is injected into the non-foamed sheet. Impregnated with active gas. When the inert gas is sufficiently impregnated, the pressure is released (usually up to atmospheric pressure), and bubble nuclei are generated in the resin composition constituting the sheet. Bubble nuclei may be grown as they are at room temperature, but in some cases they may be grown by heating. As a heating method, a known or conventional method such as a water bath, an oil bath, a hot roll, a hot air oven, a far infrared ray, a near infrared ray, or a microwave can be adopted. After the bubbles are grown in this manner, the resin foam can be obtained by rapidly cooling with cold water or the like and fixing the shape. In addition, the molded object used for foaming can use a thing of various shapes according to a use not only in a sheet-like thing. Moreover, the molded object used for foaming can also be produced by other molding methods such as injection molding in addition to extrusion molding and press molding.

  Next, the example which manufactures a resin foam by a continuous system is shown below. While kneading the resin composition using an extruder such as a single screw extruder or a twin screw extruder, a high-pressure inert gas was injected and the resin composition was sufficiently impregnated with the inert gas. Later, the pressure is released by extrusion (usually up to atmospheric pressure) and in some cases the bubbles are grown by heating. After the bubbles are grown, the resin foam can be obtained by rapidly cooling with cold water or the like to fix the shape. The foam molding can be performed using an injection molding machine in addition to the extruder. The shape of the foam is not particularly limited, and may be any of a sheet shape, a prismatic shape, a cylindrical shape, an irregular shape, and the like.

  The pressure in the gas impregnation step is, for example, 6 MPa or more (for example, about 6 to 100 MPa), preferably 8 MPa or more (for example, about 8 to 100 MPa). In the case where the inert gas is carbon dioxide in a supercritical state, from the viewpoint of maintaining the supercritical state of carbon dioxide, for example, 7.4 MPa or more (for example, about 7.4 to 100 MPa), preferably 8 MPa or more (for example, 8 About 100 MPa). When the pressure is lower than 6 MPa, the bubble growth at the time of foaming is remarkable, the bubble diameter becomes too large, and a small average cell diameter (average bubble diameter) described later cannot be obtained. This is because, when the pressure is low, the amount of gas impregnation is relatively small compared to when the pressure is high, and the number of bubble nuclei formed is reduced due to a decrease in the bubble nucleus formation rate. This is because the bubble diameter becomes extremely large. Further, in the pressure region lower than 6 MPa, the bubble diameter and the bubble density change greatly only by slightly changing the impregnation pressure, so that it is difficult to control the bubble diameter and the bubble density.

  The temperature in the gas impregnation step varies depending on the composition and composition ratio of the inert gas to be used and the resin composition, and can be selected in a wide range, but is, for example, about 10 to 350 ° C. in consideration of operability. For example, the impregnation temperature when impregnating an unfoamed molded article such as a sheet with an inert gas is about 10 to 200 ° C., preferably about 40 to 200 ° C. in a batch system. Further, the impregnation temperature in the case of simultaneously performing foaming and molding by extruding a molten polymer impregnated with gas is generally about 60 to 350 ° C. in a continuous type. When carbon dioxide is used as the inert gas, the temperature during impregnation is preferably 32 ° C. or higher, particularly 40 ° C. or higher in order to maintain a supercritical state.

  Moreover, although the pressure reduction speed | rate in a pressure reduction process is not specifically limited, In order to obtain a uniform fine bubble, Preferably it is about 5-300 MPa / second. Moreover, the heating temperature in the said heating process is about 40-250 degreeC, for example, Preferably it is about 60-250 degreeC.

The resin foam thus obtained has a high expansion ratio, high closed cell properties, a uniform foam cell shape, and excellent flexibility and cushioning properties. Density of the resin foam used in the light-shielding layer of the present invention is, for example 0.2 g / cm ³ or less (0.01~0.2g / cm ³ or so), preferably 0.02～0.15G / cm ³ , more preferably in the range of 0.03 to 0.12 g / cm ³ .

  30-250 micrometers is preferable and, as for the average cell diameter (average cell diameter) of the resin foam used for the light-shielding layer of this invention, More preferably, it is 40-150 micrometers. If the average cell diameter is less than 30 μm, sufficient cushioning properties may not be obtained, and the effect of preventing bleeding due to pressing may not be sufficient, and if it exceeds 250 μm, it may be difficult to reduce the thickness of the foam. .

  The thickness of the light-shielding layer of the present invention is preferably from 0.1 to 1.5 mm, more preferably from 0.3 to 1.0 mm. If the thickness of the light-shielding layer is thicker than 1.5 mm, the LCD may be distorted due to repulsion of the foam. If it is thinner than 0.1 mm, the cushioning property is lowered, and the effect of suppressing bleeding against pressing, etc. May decrease.

  The transmittance of the light-shielding layer of the present invention with respect to light having a wavelength of 550 nm is preferably 0.3 (%) or less [0 to 0.3 (%)], more preferably 0.1 (%) or less [ More preferably, it is 0.05 (%) or less], and in particular, 0.03 (%) or less [particularly 0.01 (%) or less] is suitable.

[Reflective layer]
The reflective light-shielding structure of the present invention has a white or silver reflective layer.

The white referred to in the present ^{invention, L * a * b * L} * is defined by a color system, 87 or more (87 to 100) [preferably 90 or more (90 to 100), more preferably 92 or more (92 To 100)]. Note that a ^* and b ^* defined by the L ^* a ^* b ^* color system can be appropriately selected according to the value of L ^* . As a ^* and b ^* , for example, both are preferably in the range of −10 to 10 (particularly −5 to 5), and in particular, both are 0 or almost 0 (range of −2 to 2). It is preferable that

Further, silver means a silver color in which L ^* defined by the L ^* a ^* b ^* color system is 70 to 90 (preferably 72 to 88, more preferably 75 to 85). ing. Note that a ^* and b ^* defined by the L ^* a ^* b ^* color system can be appropriately selected according to the value of L ^* . As a ^* and b ^* , for example, both are preferably in the range of −10 to 10 (particularly −5 to 5), and in particular, both are 0 or almost 0 (range of −2 to 2). It is preferable that

  The reflective layer of the reflective / light-shielding structure of the present invention is not particularly limited as long as it is a layer exhibiting the above white or silver color, and is a resin layer (for example, a film layer, a printed layer) or a metal layer (for example, a metal vapor deposition layer, a metal). Foil). Among these, the reflective layer of the present invention is preferably a white or silver film layer, a white or silver printing layer (coating layer), and a metal vapor deposition layer, and particularly preferably a white film layer.

  When the reflective layer of the present invention is a white or silver film layer, the film layer is preferably formed of a resin composition obtained by adding a white or silver colorant to a film-forming resin.

  The colorant used in the film layer as the reflective layer may be any colorant (coloring material) such as a pigment or a dye, but a pigment can be preferably used. Specifically, examples of the white colorant include titanium oxide (titanium dioxide such as rutile titanium dioxide and anatase titanium dioxide), zinc oxide, aluminum oxide, silicon oxide, zirconium oxide, magnesium oxide, calcium oxide, and oxidation. Tin, barium oxide, cesium oxide, yttrium oxide, magnesium carbonate, calcium carbonate (light calcium carbonate, heavy calcium carbonate, etc.), barium carbonate, zinc carbonate, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide, Aluminum silicate, magnesium silicate, calcium silicate, barium sulfate, calcium sulfate, barium stearate, zinc white, zinc sulfide, talc, silica, alumina, clay, kaolin, titanium phosphate, mica, gypsum, white carbon, diatomaceous earth, vent Inorganic white colorants such as Ito, lithopone, zeolite, sericite, and hydrous halloysite, acrylic resin particles, polystyrene resin particles, polyurethane resin particles, amide resin particles, polycarbonate resin particles, silicone resin particles And organic white colorants such as urea-formalin resin particles and melamine resin particles. A fluorescent whitening agent can also be used as the white colorant, and the fluorescent whitening agent can be appropriately selected from known fluorescent whitening agents. These white colorants can be used alone or in combination of two or more. Examples of the silver colorant include silver and aluminum. The silver colorants can be used alone or in combination of two or more.

  The resin (film layer resin) used for the film layer which is the reflective layer of the present invention is not particularly limited as long as it is film-forming. For example, polyester (polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, poly Butylene naphthalate), polyolefin (polyethylene, polypropylene, ethylene-propylene copolymer, etc.), polyvinyl alcohol, polyvinylidene chloride, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyamide, polyimide, cellulose Fluorine resin, polyether, polystyrene resin (polystyrene, etc.), polycarbonate, polyethersulfone and the like. In the case of using a white color material or a silver color material, it is preferable to use a transparent resin as the resin. Resin can be used individually or in combination of 2 or more types.

  When making the whole reflection light-shielding structure of this invention flame-retardant, you may add a flame retardant to a reflective layer. As the flame retardant in that case, in addition to the metal hydroxides exemplified as the flame retardant in the light-shielding layer, bromine compounds such as pentabromodiphenyl ether, octabromodiphenyl ether, decabromodiphenyl ether, tetrabromobisphenol A, hexabromocyclododecane, Chlorine compounds such as chlorinated paraffin compounds, phosphoric acid esters such as triphenyl phosphate, and phosphorus compounds such as red phosphorus can also be used. Even when the reflective layer does not contain the flame retardant and the flame retardant is contained only in the light shielding layer, for example, when the reflective layer is thinner than the light shielding layer, The entire structure can be made flame retardant.

  In the film layer resin, if necessary, for example, known additives such as fillers, anti-aging agents, antistatic agents, softeners, ultraviolet absorbers, antioxidants, plasticizers, surfactants, etc. May be included.

  The film layer, which is the reflective layer of the present invention, can be formed by a method of molding the film layer resin into a sheet shape using a molding method such as extrusion molding, inflation molding, calendar molding, or the like. Moreover, as a method of laminating a film layer on a foam which is a light-shielding layer, laminating with an adhesive or a pressure-sensitive adhesive, thermal lamination, co-extrusion and the like can be mentioned.

  Among the above, the film layer that is a reflective layer is preferably a white polyester film, particularly preferably a white polyethylene terephthalate (PET) film, from the viewpoints of cost and handleability. Such white PET film is also available on the market. For example, “TU3” manufactured by Teijin DuPont Co., Ltd., “W400C” manufactured by Mitsubishi Polyester Film Co., Ltd., “Lumirror” manufactured by Toray Industries, Inc., and the like are used. be able to.

  When the reflective layer of the present invention is a printing layer (coating layer), the reflective layer is coated with an ink composition on a substrate such as a light-shielding layer, and dried as necessary. Can be formed. In addition, when a reflective layer is a printing layer, it can also be set as the reflective adhesive layer which has adhesiveness.

  The ink composition (white ink composition, silver ink composition, etc.) for forming the reflective layer of the present invention can be a known and commonly used ink composition, and is not particularly limited. In addition to the agent, it contains a binder, a dispersant, a solvent, and the like as necessary. The binder is not particularly limited, and examples thereof include polyurethane resins, phenol resins, epoxy resins, urea melamine resins, silicone resins, phenoxy resins, methacrylic resins, acrylic resins, polyarylate resins, polyester resins. (Polyethylene terephthalate, etc.), polyolefin resin (polyethylene, polypropylene, ethylene-propylene copolymer, etc.), polystyrene resin (polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer) Polymer, acrylonitrile-butadiene-styrene resin, etc.), polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyvinylidene chloride, polycarbonate, celluloses (cellulose acetate resin) Such as ethyl cellulose resin), known resin (thermoplastic resin such as polyacetal, etc. thermosetting resin or photo-curable resin). A binder can be used individually or in combination of 2 or more types.

  As a method for forming the printing layer (coating layer) which is the reflective layer, various printing methods (gravure printing method, flexographic printing method, offset printing method, letterpress printing method, screen printing method, etc.) and coating methods (spin coating method). , Die coating method, bar coating method, fountain method, etc.).

  Furthermore, the reflective layer of the present invention can also be formed by evaporating a metal component capable of exhibiting a silver color such as silver or aluminum on the surface of the light shielding layer. As a vapor deposition method, a reduced pressure vapor deposition method (vacuum vapor deposition method), a physical sputtering method, a chemical sputtering method, or the like can be employed.

  The reflective layer of the present invention may be a single layer, but may have a multilayer form from the viewpoint of further improving the reflectivity. The number of reflective layers can be appropriately selected from a range of 1 to 10, for example.

  The thickness of the reflective layer of the present invention (when the reflective layer has a multilayer structure, the thickness of the entire reflective layer of the multilayer structure) varies depending on the type of the reflective layer, and is not particularly limited. In some cases, the thickness is preferably 4 to 70 μm, more preferably 10 to 50 μm. In the case of a printed layer, 1-15 micrometers is preferable, More preferably, it is 1-10 micrometers. In the case of a metal vapor deposition layer, for example, 0.3 to 2 μm is preferable, more preferably 0.4 to 1 μm, and still more preferably 0.4 to 0.5 μm.

  The reflectance of the reflective layer surface of the present invention is preferably 60 (%) or more [60 to 100 (%)], more preferably 70 (%) or more, further preferably 80 (%) or more, most preferably Preferably it is 85 (%) or more.

[Adhesive layer]
The reflective / light-shielding structure of the present invention can be used as a reflective / light-shielding pressure-sensitive adhesive tape or sheet by having an adhesive layer on at least one surface. Moreover, it can be used as a reflective light-shielding double-sided adhesive tape or a sheet | seat by having an adhesive layer on the surface of both sides. The pressure-sensitive adhesive layer may be, for example, a reflective pressure-sensitive adhesive layer (a reflective layer and a pressure-sensitive adhesive layer), one of which has a white colorant. The pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer is not particularly limited. For example, a urethane-based pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, a polyester-based pressure-sensitive adhesive, and a polyamide-based pressure-sensitive adhesive. And known adhesives such as epoxy adhesives, vinyl alkyl ether adhesives, and fluorine adhesives. Among these, acrylic adhesives and rubber adhesives are particularly preferable. These pressure-sensitive adhesives can be used alone or in combination of two or more. In addition, the form of an adhesive is not specifically limited, For example, an emulsion type adhesive, a solvent-type adhesive, a hot-melt-type adhesive (hot melt type adhesive) etc. are mentioned. The pressure-sensitive adhesive layer may be either a single layer or a multilayer.

  The acrylic pressure-sensitive adhesive contains an acrylic polymer as a main component or a base polymer. The acrylic polymer is not particularly limited, but as a main constituent monomer component (monomer main component), a (meth) acrylic acid alkyl ester having a linear or branched alkyl group (acrylic acid alkyl ester, methacrylic acid). Acid alkyl ester) is preferably used. Specifically, as the (meth) acrylic acid alkyl ester, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, (meth) acrylic acid Butyl, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isoamyl (meth) acrylate, neopentyl (meth) acrylate, (meta ) Hexyl acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, ( (Meth) acrylic acid decyl, (meth) acrylic acid isodecyl, (meth) acrylic acid Ndeshiru, like (meth) dodecyl acrylate. The (meth) acrylic acid alkyl ester can be used alone or in combination of two or more.

  As the monomer component constituting the acrylic polymer, other monomer components that can be copolymerized with (meth) acrylic acid alkyl ester (“copolymerizable monomer”) can be used as long as (meth) acrylic acid alkyl ester is the main monomer component. May be referred to as “components”). In addition, as (meth) acrylic-acid alkylester, it is preferable to use in the ratio of 50 weight% or more with respect to the monomer component whole quantity which comprises an acryl-type polymer. When the proportion of the alkyl (meth) acrylate is less than 50% by weight based on the total amount of monomer components constituting the acrylic polymer, the characteristics (such as adhesiveness) of the acrylic polymer are difficult to develop. There is.

  As the copolymerizable monomer component, it can be used for introducing a crosslinking point into the acrylic polymer or for increasing the cohesive force of the acrylic polymer. The copolymerizable monomer components can be used alone or in combination of two or more.

  Specifically, as the copolymerizable monomer component, a functional group-containing monomer component (particularly, heat for introducing a crosslinking point that is thermally crosslinked to the acrylic polymer) is introduced in order to introduce a crosslinking point into the acrylic polymer. Crosslinkable functional group-containing monomer component) can be used. Such a functional group-containing monomer component is not particularly limited as long as it is a monomer component that can be copolymerized with a (meth) acrylic acid alkyl ester and has a functional group that becomes a crosslinking point. (Meth) acrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, isocrotonic acid and other carboxyl group-containing monomers or acid anhydrides thereof (maleic anhydride, itaconic anhydride, etc.); (meth) acrylic acid 2-hydroxy Hydroxyalkyl (meth) acrylates such as ethyl, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, etc., and hydroxyl-containing monomers such as vinyl alcohol and allyl alcohol; (meth) acrylamide, N , N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, -Amide monomers such as methylol (meth) acrylamide, N-methylolpropane (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide; aminoethyl (meth) acrylate, (meth) Amino group-containing monomers such as N, N-dimethylaminoethyl acrylate and t-butylaminoethyl (meth) acrylate; Epoxy group-containing monomers such as glycidyl (meth) acrylate and methyl glycidyl (meth) acrylate; acrylonitrile; Cyano-containing monomers such as methacrylonitrile; N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinyl Roll, N- vinylimidazole, N- vinyloxazole, N- vinyl morpholine, N- vinyl caprolactam, such a monomer having a nitrogen atom-containing ring such as N- (meth) acryloyl morpholine. As the functional group-containing monomer component, a carboxyl group-containing monomer such as acrylic acid or an acid anhydride thereof can be suitably used.

  Further, as the copolymerizable monomer component, other copolymerizable monomer components can be used in order to increase the cohesive strength of the acrylic polymer. Other copolymerizable monomer components include, for example, vinyl ester monomers such as vinyl acetate and vinyl propionate; styrene monomers such as styrene, substituted styrene (α-methylstyrene, etc.) and vinyltoluene; (meth) acrylic acid Non-aromatic ring-containing (meth) acrylic esters such as cycloalkyl esters [cyclohexyl (meth) acrylate, cyclopentyl di (meth) acrylate, etc.], bornyl (meth) acrylate, isobornyl (meth) acrylate; (Meth) acrylic acid aryl ester [(meth) acrylic acid phenyl etc.], (meth) acrylic acid aryloxyalkyl ester [(meth) acrylic acid phenoxyethyl etc.] and (meth) acrylic acid arylalkyl ester [(meth) acrylic Acid benzyl ester] Any aromatic ring-containing (meth) acrylic acid ester; olefinic monomers such as ethylene, propylene, isoprene, butadiene, isobutylene; vinyl chloride, vinylidene chloride; isocyanate group-containing monomers such as 2- (meth) acryloyloxyethyl isocyanate; Alkoxy group-containing monomers such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate; vinyl ether monomers such as methyl vinyl ether and ethyl vinyl ether, 1,6-hexanediol di (meth) acrylate, ethylene glycol di (Meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, (poly) ethylene Glycol di (meth) acrylate, propylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) Acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, glycerin di (meth) acrylate, epoxy acrylate, polyester acrylate, urethane acrylate, divinylbenzene, butyl di (meth) acrylate, hexyl di (meth) acrylate, etc. And other polyfunctional monomers.

  Rubber adhesives include natural rubber, styrene-isoprene-styrene block copolymer (SIS block copolymer), styrene-butadiene-styrene block copolymer (SBS block copolymer), styrene-ethylene / butylene- Based on rubber components such as styrene block copolymer (SEBS block copolymer), styrene-butadiene rubber, polybutadiene, polyisoprene, polyisobutylene, butyl rubber, chloroprene rubber, silicone rubber, acrylonitrile-butadiene rubber, ethylene-propylene terpolymer Examples thereof include a rubber-based pressure-sensitive adhesive as a polymer.

  In the pressure-sensitive adhesive, if necessary, for example, a crosslinking agent, a cross-linking agent, a tackifier resin, a filler, a flame retardant, an anti-aging agent, an antistatic agent, a softening agent, an ultraviolet absorber, an antioxidant. In addition, known additives such as plasticizers and surfactants may be included. Moreover, the adhesive layer may contain a heat conductive compound from the viewpoint of enhancing the heat dissipation function of the reflective / light-shielding adhesive tape or sheet. The thermal conductive compound is not particularly limited as long as it is a compound having thermal conductivity. For example, metal oxide such as alumina, silica, zinc oxide, and aluminum oxide; metal nitride such as aluminum nitride, boron nitride, and silicon nitride A metal carbide such as silicon carbide or boron carbide; a metal hydroxide such as aluminum hydroxide.

  It does not restrict | limit especially as thickness of an adhesive layer, For example, it can select suitably from the range of 2-100 micrometers (preferably 5-80 micrometers).

  The method of forming the pressure-sensitive adhesive layer is not particularly limited. For example, a method of applying a pressure-sensitive adhesive on a predetermined surface and drying or curing as necessary, or a method of applying a pressure-sensitive adhesive on a separator (release liner). Then, after drying or curing as necessary, a pressure-sensitive adhesive layer is formed, and then the pressure-sensitive adhesive layer is bonded onto a predetermined surface and transferred. In applying the pressure-sensitive adhesive, a conventional coating machine (for example, gravure roll coater, reverse roll coater, kiss roll coater, dip roll coater, bar coater, knife coater, spray coater, etc.) can be used.

[Reflective light shielding structure]
Since the reflective light-shielding structure of the present invention has a light-shielding layer made of a black foam, the light transmittance is low. By using the surface of the light-shielding layer side as the liquid crystal display module side, “light is also emitted from the backlight. Can be prevented and the visibility of the display can be improved. From this viewpoint, the transmittance of the reflective / light-shielding structure of the present invention is preferably 0.3 (%) [0 to 0.3 (%)] or less, more preferably 0.1 (%) or less [more preferably 0. 0.05 (%) or less], and 0.03 (%) or less [particularly 0.01 (%) or less] is preferable. The transmittance (%) is obtained by irradiating light having a wavelength of 550 nm from one surface side of the reflective light-shielding structure using a spectrophotometer manufactured by Hitachi, Ltd. (device name “U4100 type spectrophotometer”). Thus, it is obtained by measuring the intensity of the light transmitted to the other surface side.

  Moreover, since the reflective light-shielding structure of this invention has a white or silver reflective layer, the reflective layer side surface has a high reflectance. For this reason, by using the reflective layer side surface as the backlight side, the luminance can be increased by reflecting the backlight light, and the power consumption can be reduced because the reflected light can be used. From this viewpoint, the reflectance of the surface on the reflective layer side of the reflective / light-shielding structure of the present invention is preferably 60 (%) or more [for example, 60 to 100 (%)], more preferably 70 (%) or more, More preferably, it is 80 (%) or more. The reflectance (diffuse reflectance) (%) of the reflection / light-shielding structure was measured using a spectrophotometer (device name “MPS-2000”) manufactured by Shimadzu Corporation to reflect light having a wavelength of 550 nm. It is calculated | required by irradiating from the reflective layer side and measuring the intensity | strength of the light reflected on the surface which irradiated the said light.

  In addition to the above effects, the reflective / light-shielding structure of the present invention has an appropriate cushioning property because the light-shielding layer is made of a foam, and, for example, when used as a touch panel, it takes a finger press. Since the stress of the pressure can be dispersed, it is preferable because “bleeding” of the liquid crystal display surface due to the pressure hardly occurs. In addition, due to the cushioning property, for example, in the case of a touch panel using a touch pen, the writing taste and feel of the touch pen are improved, which is preferable. Furthermore, the liquid crystal display using the reflective / light-shielding structure of the present invention has good impact resistance.

  Furthermore, in the case of the reflective / light-shielding pressure-sensitive adhesive tape or sheet having a pressure-sensitive adhesive layer, the reflective / light-shielding structure of the present invention has a light-shielding layer made of a foam, so that it is adhered to a liquid crystal display module or a backlight unit. Furthermore, the followability to the shape of the adherend is increased, and the adhesion is improved. In particular, a narrow reflective / light-shielding pressure-sensitive adhesive tape used for a small liquid crystal display device or the like is also preferable because sufficient adhesive force is exhibited and adhesion reliability is kept high.

  In addition, since the reflective light-shielding structure of the present invention uses a black foam for the light-shielding layer, it is preferable because color loss due to pinholes does not occur compared to the case where the light-shielding layer is provided by printing.

  When the resin foam used for the light-shielding layer of the present invention contains a flame retardant, the reflective light-shielding structure of the present invention has high flame retardancy, so that, for example, for digital cameras, digital video cameras, game machines, etc. This is useful for liquid crystal display applications. As the flame retardancy, for example, it is preferable to satisfy the flame retardancy standards of UL94 V-0 and UL94 HF-1.

  In the present invention, the reflection / light-shielding structure may have a form in which sheet-like structures are laminated, or may have a form wound in a roll shape. Further, when incorporated into a liquid crystal display device, it is used by being punched into a frame shape. In addition, when it is a reflection light-shielding adhesive tape or a sheet | seat, the surface of each adhesive layer may be protected by the well-known separator (release liner).

  The reflective / light-shielding structure of the present invention may have a tape-shaped portion having a width of 0.5 to 10 mm (preferably 1.0 to 6.0 mm). Such a reflection / light-shielding structure can suppress a decrease in followability of a minute step due to a narrow width even in an elongated tape-shaped portion. In other words, such a reflective / light-shielding structure can be applied to a tape-shaped portion even with respect to a minute step (for example, a height of 2.0 to 1000 μm) that cannot be conventionally followed in an elongated tape-shaped portion. Follow-up is possible. For this reason, if such a reflection light-shielding structure has an adhesive layer, it has favorable adhesive reliability.

  The reflective / light-shielding structure of the present invention may have two or more tape-shaped portions. Moreover, when it has two or more tape-shaped site | parts, the width | variety may be the same and may differ. Furthermore, the reflective / light-shielding structure may be composed of only a tape-shaped part.

  The reflective / light-shielding structure according to the present invention includes a liquid crystal display module unit and a backlight in a liquid crystal display device (LCD) (particularly a small liquid crystal display device) used in a so-called “mobile phone” or a so-called “PDA”. It is suitably used as a liquid crystal display member inserted into the unit. Furthermore, in the case of a reflection / light-shielding pressure-sensitive adhesive tape or sheet (particularly, a reflection / light-shielding double-sided pressure-sensitive adhesive tape or sheet), it is suitably used for fixing the liquid crystal display module unit and the backlight unit.

[Liquid Crystal Display]
The liquid crystal display device of the present invention comprises at least a liquid crystal display module unit, a backlight unit, and the reflective / light-shielding structure of the present invention. Hereinafter, it demonstrates, referring drawings. FIG. 1 is a schematic view showing an arrangement of a liquid crystal display module unit, a backlight unit, and a reflection / light-shielding structure in a liquid crystal display device of the present invention. In the liquid crystal display device of the present invention, a reflective / light-shielding structure 2 processed into a frame shape is provided on a backlight unit 1 with a reflective layer as a backlight unit side and a light-shielding layer as a liquid crystal display module unit side. The liquid crystal display module unit 3 is provided on the top.

  In the liquid crystal display device of the present invention, the reflective / light-shielding structure of the present invention having cushioning properties is provided under the liquid crystal display module unit. Etc.), the pressure (stress) is likely to be dispersed, and “bleeding” of the liquid crystal display is less likely to occur. Moreover, since it is excellent in impact resistance, even in the case of a display device in which a protective plate such as an acrylic plate is not provided on the liquid crystal display module, damage due to a drop impact or the like hardly occurs. Further, the visibility of the liquid crystal display is good due to the effect of the light shielding layer, and the backlight light is effectively utilized by the reflective layer, so that power consumption can be reduced.

  The liquid crystal display device of the present invention is useful as a liquid crystal display device such as a mobile phone, a digital camera, a portable small personal computer, a portable game machine, a handy terminal, a PDA, and a portable audio player, particularly as a liquid crystal display device with a touch panel. Especially, it is preferably used for the touch panel use with a high request | requirement of the bleeding prevention with respect to a press, or a small-sized liquid crystal display device use.

[Methods for measuring physical properties and methods for evaluating effects]
Below, the measuring method used by this application and the evaluation method of an effect are illustrated.

(1) Measurement method of L ^* , a ^* , b ^{* Using} a color difference meter (manufactured by Konica Minolta Co., Ltd., apparatus name “CR-200”), it is defined in the L ^* a ^* b ^* color system. L ^* , a ^* , b ^* were measured.

(2) Reflectance Using a spectrophotometer (manufactured by Shimadzu Corporation, apparatus name “MPS-2000”), irradiates light having a wavelength of 550 nm on the reflective layer side surface of the reflective light-shielding structure, The reflectance (%) is obtained by measuring the intensity of the light reflected by the light-irradiated surface.

(3) Transmittance Using a spectrophotometer (manufactured by Hitachi, Ltd., device name “U4100 type spectrophotometer”), light having a wavelength of 550 nm is irradiated from one side of the reflective light shielding structure, The transmittance (%) is obtained by measuring the intensity of the light transmitted to the other surface side.
When the transmittance of only the light-shielding layer (black foam) is used, measurement can be performed by changing the sample to only the light-shielding layer.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. Examples 1, 3, 4, 5, 9, 10, and 11 are outside the scope of the present invention, but are described as reference examples.

Example 1
(Light-shielding layer)
45 parts by weight of polypropylene, 45 parts by weight of a polyolefin-based elastomer, 10 parts by weight of polyethylene, 10 parts by weight of magnesium hydroxide, and 10 parts by weight of carbon in a twin-screw kneader manufactured by Japan Steel Works (JSW) The mixture was kneaded at a temperature of 200 ° C., extruded into a strand, cooled to water, and formed into a pellet. The pellets were put into a single screw extruder manufactured by Nippon Steel Works, and carbon dioxide gas was injected under an atmosphere of 220 ° C. at a pressure of 13 (12 after injection) MPa. Carbon dioxide gas was injected at a ratio of 5% by weight with respect to the total amount of the polymer. After sufficiently saturating the carbon dioxide gas, it was cooled to a temperature suitable for foaming and then extruded from a die to obtain a black foam. In this black foam, the density was 0.04 g / cm ³ , the average cell diameter was 70 μm, and the thickness was 0.5 mm. The black foam had L ^* defined by L ^* a ^* b ^* color system of 32, a ^* of 0.39, and b ^* of −0.1.

(Reflective layer)
As the reflective layer, a white polyethylene terephthalate film (trade name “Lumirror E60L” manufactured by Toray Industries, Inc.) having a thickness of 13 μm was used.

(Adhesive)
96 parts by weight of n-butyl acrylate, 4 parts by weight of acrylic acid, 0.2 parts by weight of azobisisobutyronitrile, and 233 parts by weight of ethyl acetate as a polymerization solvent were put into a separable flask, and nitrogen gas was introduced. The mixture was stirred for 1 hour. Thus, after removing oxygen in the polymerization system, the reaction was carried out at 60 ° C. for 7 hours to obtain an acrylic pressure-sensitive adhesive solution having a solid content concentration of 30% by weight. The weight average molecular weight of the acrylic polymer in this solution was 600,000.

  The black foam (light-shielding layer) obtained above and a white PET film (reflective layer) were laminated. Subsequently, the acrylic pressure-sensitive adhesive layer (thickness: 20 μm) obtained by applying and drying the acrylic pressure-sensitive adhesive solution on the separator was bonded to both surfaces of the obtained laminate, and pressure-sensitive adhesive layer / light-shielding layer / A reflection / light-shielding structure (reflection / light-shielding double-sided pressure-sensitive adhesive sheet, reflection / light-shielding member) having a layer structure of a reflective layer / adhesive layer was obtained.

(Liquid crystal display device)
The reflective / light-shielding double-sided pressure-sensitive adhesive sheet obtained above was punched into a frame shape having a length of 39 mm × width of 29 mm and a width of 2 mm.
Next, the frame-shaped reflective light-shielding double-sided pressure-sensitive adhesive sheet was stuck on the backlight unit so as to contact the reflective layer side. Further, an LCD module unit was adhered and fixed to the light shielding layer side to obtain a liquid crystal display device.

Example 2
As the light-shielding layer, the same black foam as in Example 1 was used. Aluminum was vacuum-deposited on one surface of the light-shielding layer to form a silver reflective layer (aluminum layer) having a thickness of 50 nm. Further, in the same manner as in Example 1, an adhesive layer is provided on both surfaces of the laminate, and a reflection / light-shielding structure (reflection / light-shielding property) having a layer structure of pressure-sensitive adhesive layer / light-shielding layer / reflective layer / pressure-sensitive adhesive layer. A double-sided pressure-sensitive adhesive sheet and a reflection / light-shielding member) were obtained.
Further, a liquid crystal display device was obtained in the same manner as in Example 1.

Example 3
The said acrylic adhesive was apply | coated to both surfaces of a white PET film (reflection layer), it dried, and the double-sided adhesive tape which provided the 20-micrometer-thick adhesive layer was obtained.
The double-sided pressure-sensitive adhesive tape (reflective tape) is bonded to one side of the black foam (light-shielding layer) obtained above, and an acrylic pressure-sensitive adhesive layer (thickness: provided on the separator on the other side of the black foam) 20 μm) to obtain a reflective light-shielding structure (reflective light-shielding double-sided pressure-sensitive adhesive tape, reflective light-shielding member) having a layer structure of pressure-sensitive adhesive layer / light-shielding layer / pressure-sensitive adhesive layer / reflective layer / pressure-sensitive adhesive layer It was.
And the width | variety of the tape-shaped site | part of this reflective light-shielding member was 2 mm.

Example 4
A reflective / light-shielding structure was produced in the same manner as in Example 3, and the width of the tape-shaped portion of the reflective / light-shielding member was 5 mm.

Example 5
A reflective / light-shielding structure was prepared in the same manner as in Example 3, and the width of the tape-shaped portion of the reflective / light-shielding member was 10 mm.

Example 6
A reflective / light-shielding structure was produced in the same manner as in Example 2, and the width of the tape-shaped portion of the reflective / light-shielding member was 2 mm.

Example 7
A reflective / light-shielding structure was produced in the same manner as in Example 6, and the width of the tape-shaped portion of the reflective / light-shielding member was 5 mm.

Example 8
A reflective / light-shielding structure was produced in the same manner as in Example 6, and the width of the tape-shaped portion of the reflective / light-shielding member was 10 mm.

Example 9
A reflective light-shielding structure was prepared in the same manner as in Example 3 except that an aluminum-deposited PET film (thickness: 12 μm, manufactured by Toray Film Processing Co., Ltd.) was used for the reflective layer. The width of the tape-shaped part was 2 mm.

Example 10
A reflective / light-shielding structure was produced in the same manner as in Example 9, and the width of the tape-shaped portion of the reflective / light-shielding member was 5 mm.

Example 11
A reflective / light-shielding structure was produced in the same manner as in Example 9, and the width of the tape-shaped portion of the reflective / light-shielding member was 10 mm.

Comparative Example 1
Reflecting in the same manner as in Example 1 except that a laminate obtained by forming a light-shielding layer by applying black printing (thickness: 7 μm) to one side of a white PET film (reflective layer) is used. A light shielding structure was prepared, and the width of the tape-shaped portion of the reflective light shielding member was 2 mm.

Comparative Example 2
A reflection / light-shielding structure was prepared in the same manner as in Comparative Example 1, and the width of the tape-shaped portion of the reflection / light-shielding member was 5 mm.

Comparative Example 3
A reflective / light-shielding structure was prepared in the same manner as in Comparative Example 1, and the width of the tape-shaped portion of the reflective / light-shielding member was 10 mm.

(Evaluation)
About the Example and the comparative example, the adhesiveness and shock absorption which can follow a level | step difference were evaluated with the following measuring method. The evaluation results are shown in Table 1.

[Measurement Method of Adhesiveness that can Follow Level Differences (Measurement Method of 90 Degree Peel Peeling Force for Substrates with Minute Steps)]
After storing the reflective / light-shielding member for 24 hours or more in an atmosphere of 23 ± 2 ° C. and 50 ± 5 RH% (pretreatment conditions: according to JIS Z 0237), the length is cut to 100 mm in the same atmosphere. And a polycarbonate plate (Mitsubishi Rayon Co., Ltd.) having a minute step (height: 300 μm) provided by laminating a brightness enhancement film (trade name “BEF”, manufactured by Sumitomo 3M Co., Ltd.). They were bonded together so that the minute step was at the center of the reflection / light-shielding member (see FIG. 2), and a 2 kg rubber roller was reciprocated once and pressed, and left for 30 minutes. After standing, a 90 ° peel peel force was measured using a tensile tester (trade name “TG-1kN” manufactured by Minebea Co., Ltd.) at a peel rate of 300 mm / min.

(Measurement method of shock absorption)
The impact force was measured using a pendulum tester disclosed in JP-A-2006-47277.
In the pendulum tester, an impactor made of a steel ball having a diameter of 19 mm and a weight of 28 g (0.27 N) is attached by a support bar having a length of 350 mm on a support plate (acrylic plate). And after raising a support bar to arbitrary predetermined angles and fixing, it is possible to make a steel ball collide with a support plate with a switch. The impact force at the time of the collision is detected by a pressure sensor and measured by MULTI-Puropose FTT Analyzer (manufactured by Ono Sokki Co., Ltd.).
Impact absorption is the impact when the impact force of the support plate only: F0, and a 20 mm square reflective / light-shielding member is used as a test piece, and the test piece is set between an aluminum plate and a support plate (acrylic plate). Force (impact force when inserting a test piece): F1 was measured and calculated from the following formula.
Shock absorption (%) = (F0−F1) / F0 × 100

  It was confirmed that the reflective / light-shielding member of the example suppressed the reduction in adhesiveness due to the tape width becoming narrower than that of the comparative example. It was also confirmed that the impact absorbability was remarkably improved. For this reason, this invention can provide the reflective light-shielding member excellent in impact-resistant absorption and adhesive reliability.

It is the schematic which showed arrangement | positioning of the liquid crystal display module unit in a liquid crystal display device of this invention, a backlight unit, and a reflective light-shielding structure. It is the schematic which showed what attached the reflective light-shielding member on the polycarbonate board which provided the micro level | step difference used in the measuring method of the 90 degree | times peel peeling force with respect to the to-be-adhered body which has a micro level | step difference.

DESCRIPTION OF SYMBOLS 1 Backlight unit 2 Reflection light-shielding structure 3 Liquid crystal display (LCD) module unit 4 Polycarbonate board 5 Brightness improvement film 6 Reflection light-shielding member 2a Appearance of what reflected light-shielding member was bonded to the polycarbonate board which provided the micro level | step difference 2b Minute Cross section of a reflection-shielding member bonded to a polycarbonate plate with steps

Claims (12)

It has a light-shielding layer made of black foam and a white or silver reflective layer, the thickness of the light-shielding layer is 0.1 to 1.5 mm, and the average cell diameter of the black foam is 30 to 250 μm. Yes, the density of the black foam is 0.01 to 0.2 g / cm ³ , the reflective layer is a metal deposition layer,
A reflection / light-shielding structure, which is an adhesive tape or sheet having an adhesive layer having a thickness of 2 to 100 μm on at least one surface.   The reflection / light-shielding structure according to claim 1, wherein the reflective / light-shielding structure has at least an elongated tape-like portion, and the width of the tape-like portion is 0.5 to 10 mm.   The reflective light-shielding structure according to claim 1 or 2, wherein the black foam is a black polyolefin resin foam obtained by foaming a polyolefin resin composition using a high-pressure inert gas.   The reflective light-shielding structure according to claim 3, wherein the polyolefin-based resin composition contains 1 to 30% by weight of a colorant based on the entire resin composition.   The reflective / light-shielding structure according to claim 3 or 4, wherein the inert gas is carbon dioxide or nitrogen.   The reflective / light-shielding structure according to claim 3, wherein the inert gas is in a supercritical state.   The reflective / light-shielding structure according to claim 1, wherein the reflective layer is a white polyester film.   The reflective light-shielding structure according to any one of claims 1 to 7, wherein the black foam includes a flame retardant, and the black foam has flame retardancy.   The reflective light-shielding structure according to claim 8, wherein the entire reflective light-shielding structure has flame retardancy.   The reflective light-shielding structure according to any one of claims 1 to 9, wherein the pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive layer.   It is a method of manufacturing the reflection light-shielding structure of any one of Claims 1-10, Comprising: After impregnating the foamable resin composition containing a coloring agent with an inert gas, pressure is released. A method for producing a reflective light-shielding structure, characterized in that a light-shielding layer made of a black foam obtained by forming bubbles and a white or silver reflective layer are laminated to obtain a reflective light-shielding structure.   A liquid crystal display module unit, a backlight unit, and a liquid crystal display device having the reflection / light-shielding structure according to any one of claims 1 to 10, wherein the reflection / light-shielding structure includes a liquid crystal display module unit and a backlight unit. A liquid crystal display device, which is located between the two.

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