JP2004066556A - Transparent joining member, transparent laminate, and method for producing the laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transparent joining member which is excellent in transparency and shock-absorbing properties and has no optical distortion, a laminate having an optical function layer and the transparent joining member, and to provide a method for producing the laminate. <P>SOLUTION: In the transparent joining member having a transparent plate-like main body, a transparent substrate having an optical function layer and a rigid transparent substrate are joined together. The main body is made of a plate-like crosslinked polyorganosiloxane 1-5 mm in thickness. The rubber hardness of the main body is 40° or below, and when the rubber hardness is 0° or below, the penetration is 20 or below. In the transparent laminate, a transparent substrate having an optical function layer, the transparent joining member, and a mold release film are laminated in turn. In the method for producing the laminate, two lengthy films are made to travel at a distance in parallel to each other. A deaerated raw material for the crosslinked polyorganosiloxane is injected into a space formed by the traveling films and sealing parts formed in both end parts of the films, and the polyorganosiloxane is crosslinked while being held between the traveling films. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a transparent joining member, a transparent laminate, and a method for producing the same.
[0002]
[Prior art]
Optics such as an anti-reflection film, an infrared absorption film, a polarizing film, an optical retardation layer, a light diffusion layer, or an electromagnetic wave absorption film on the front of large flat displays such as flat-panel cathode ray tubes, liquid crystal displays, plasma displays, field emission displays, and projection TVs. When a transparent base having a functional layer is provided, it is bonded to a rigid transparent base such as a front glass of a display device using a transparent bonding member.
[0003]
JP-A-7-168005 and JP-A-2000-249804 disclose, as a transparent substrate having an optical functional layer, a layer composed of a resin having self-healing properties and scratch resistance, and a non-crystalline fluoropolymer. An optical article having an anti-reflection layer has been proposed. As the resin forming the resin layer having self-healing properties and scratch resistance, acrylic rubber-like resin, silicone rubber-like resin, olefin-based elastomer, styrene-based resin A transparent elastic body such as an elastomer or a polyurethane resin is exemplified, and a cross-linked polyurethane resin is particularly preferred. The thickness of the transparent elastic layer is, for example, 0.2 to 0.3 mm.
The formation of the transparent elastic layer is usually performed on the optical component by coating or film bonding. It is customary to coat an antireflection layer on the transparent elastic layer thus formed.
[0004]
Japanese Patent Application Laid-Open No. 2002-107507 discloses an adhesive film for an electronic display in which an adhesive layer containing an acrylic resin is provided on one surface of a light transmitting film.
This light-transmitting film is made of a cellulose-based film such as triacetyl cellulose having one surface provided with an anti-reflection layer, an anti-glare layer and the like, and a polyester-based film such as polyethylene terephthalate.
The thickness of the light transmitting film is generally 10 to 500 μm, preferably 25 to 250 μm.
[0005]
[Problems to be solved by the invention]
Since these transparent substrates are bonded to the front glass of the display device, the bonding members must not only have high transparency so as not to reduce the light transmittance, have no optical distortion, and have an impact on the glass. When it is applied, a function to mitigate the impact and protect the glass is also required.
However, in Japanese Patent Application Laid-Open No. 2002-107507, since the light transmissive film is directly adhered to the display using an adhesive, it is not expected that the light transmissive film can reduce the impact.
In JP-A-7-168005 and JP-A-2000-249804, a soft resin such as a polyurethane-based resin is used, which is convenient for impact mitigation. Although a thickness of 1 mm or more is required, the thickness is 0.2 to 0.3 mm, and sufficient impact relaxation ability has not been obtained.
When the thickness of the joining member is increased, the shock absorbing ability is improved, but the light transmittance is reduced accordingly. In addition, after forming a transparent elastic layer as described in the publication, when an optical function layer is provided thereon, due to heat history and processing, shrinkage occurs, curling becomes severe, and the glass surface and the like are increased. There was a problem that the bonding work was not easy.
Further, as described above, when a liquid material is formed on the transparent elastic material layer, due to the fluidity of the liquid material, the film thickness becomes unstable, undulations, irregularities, bubbles, and the like are easily generated. It has been difficult to produce a laminate having no optical distortion.
In view of such circumstances, the present inventors have developed a transparent bonding member having excellent transparency, no optical distortion, and excellent impact relaxation properties, a laminate containing an optical functional layer and a transparent bonding member, and production thereof. The aim is to provide a method.
[0006]
[Means for Solving the Problems]
The transparent joining member of the present invention has a transparent plate-shaped main body, and is a joining member for joining a transparent base having an optical function layer and a rigid transparent base, wherein the plate-shaped main body has a thickness of 1 to 5 mm. The rubber hardness specified in JIS K6301 is 40 ° or less, and when the rubber hardness is 0 ° or less, the penetration specified in JIS K2220 is 20 or less. I do.
Further, the transparent laminate of the present invention is characterized in that a transparent substrate having an optical function layer, the transparent bonding member, and a release film are laminated in this order.
Further, the method for producing a transparent laminate of the present invention comprises: a) a step of degassing and mixing raw materials for producing a crosslinked polyorganosiloxane; and b) merging two long films at least one of which is a release film. From the confluence to be made, run while facing each other at a predetermined interval, the two long films running, between both films sealed at both ends of the film in the film width direction Injecting the degassed and mixed raw material of the polyorganosiloxane cross-linked product into the space formed by the sealing portion from the confluence portion while forming a bank of the production material in the confluence portion; c) A step of passing the two films running while sandwiching the raw material for producing the crosslinked polyorganosiloxane between the heating plates to crosslink the polyorganosiloxane.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
First, the transparent joining member of the present invention will be described.
In the present invention, the material of the transparent substrate having the optical functional layer is not particularly limited as long as it is transparent, and is preferably a cellulose film such as triacetyl cellulose, a polycarbonate film, a polyester film such as polyethylene terephthalate, or a polyethylene film. And polyolefin-based films such as polypropylene, polyvinyl alcohol, polyurethane films, etc., but are preferably soft, and among these, those having a polyurethane film as a base material are preferable. Examples of the polyol that is a constituent unit of the polyurethane include a polyether-based polyol, a polyester-based polyol, and a polycarbonate-based polyol, and polycaprolactone triol and polycaprolactone diol are preferable. Examples of the polyisocyanate which is a constituent unit of the polyurethane include difunctional or trifunctional isocyanates such as aromatic polyisocyanates, aliphatic polyisocyanates, and alicyclic polyisocyanates. Alternatively, an alicyclic polyisocyanate is preferable, and a specific example of such a polyisocyanate is hexamethylene diisocyanate.
[0008]
The optical functional layer of the transparent substrate is a layer having optical functions such as chromaticity adjustment, antireflection, antiglare, polarization, infrared absorption, electromagnetic wave absorption, and optical phase difference. As the chromaticity adjusting layer, a coloring layer for color correction can be exemplified. Examples of the antireflection layer include a layer obtained by alternately applying, depositing, and sputtering a substance having a low refractive index and a substance having a high refractive index. Examples of the anti-glare layer include a layer coated with a resin containing beads such as silica particles and acrylic particles, and a matte treatment layer. A commercially available polarizing film can be used for the polarizing layer. Electromagnetic wave absorption can be obtained by applying fine particles of a magnetic substance, a conductive paint, or the like. These optical functions can be one or a combination of two or more of the above optical functions. When a conductive paint is used, it also has antistatic properties.
The transparent substrate having an optical function layer is obtained by providing the optical function layer on one surface of the transparent substrate.
[0009]
The plate-shaped main body of the joining member needs to be a transparent elastic body having a thickness of 1 mm or more, preferably 1.2 mm or more and 5 mm or less. Used. By setting the thickness to 1 mm or more, a sufficient impact relaxation ability can be provided, and by setting the thickness to 5 mm or less, it is possible to prevent a decrease in transparency and the occurrence of optical distortion.
This crosslinked polyorganosiloxane has high transparency and high strength, and thus (a) a diorganopolysiloxane containing two or more alkenyl groups bonded to a silicon atom in one molecule, and (b) one molecule SiO having at least one alkenyl group bonded to a silicon atom therein_4/2A unit and an organopolysiloxane having a resin structure comprising a unit represented by the following formula;
R₃SiO_1/2
(Wherein, R represents a monovalent hydrocarbon or alkenyl group)
(C) It is preferable to contain a structural unit derived from an organohydrogenpolysiloxane having two or more hydrogen atoms bonded to a silicon atom in one molecule.
[0010]
The component (a) is a main component of the silicone gel, and generally has a main chain component composed of repeating diorganosiloxane units and having a molecular end blocked by a triorganosiloxane group. May have a branched structure, or may have a cyclic structure. In addition, it is preferable that it is linear from the point of mechanical strength. This diorganopolysiloxane has two or more alkenyl groups in one molecule. As the alkenyl group, an alkenyl group having about 2 to 8 carbon atoms, more preferably 2 to 4 carbon atoms is preferable, and a vinyl group, an allyl group, Examples thereof include a propenyl group, an isopropenyl group, a butenyl group, and a hexenyl group. More preferred alkenyl groups include a vinyl group, an allyl group, a propenyl group, an isopropenyl group, and a butenyl group.
Examples of the organo group other than the alkenyl group include an unsubstituted or substituted monovalent hydrocarbon group containing no aliphatic unsaturated bond, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group and a t-butyl group. Group, pentyl group, hexyl group, alkyl group such as octyl group, cycloalkyl group such as cyclohexyl group, aryl group such as phenyl group, tolyl group, xylyl group, biphenyl group, benzyl group, phenylethyl group, methylbenzyl group, etc. Or a group in which a part of the hydrogen atoms bonded to the carbon atoms of the above groups is substituted with a halogen atom, a cyano group, or the like. Among them, those having 1 to 10 carbon atoms are preferable, and methyl, ethyl, propyl, chloromethyl, trifluoropropyl, cyanoethyl, phenyl, and chlorophenyl are preferred specific examples. It can be mentioned.
The degree of polymerization of the organosiloxane unit is preferably from 20 to 2,000.
The alkenyl group-containing diorganosiloxane may be used alone or in combination of two or more.
[0011]
The organopolysiloxane having a three-dimensional network structure of the component (b) is SiO 2_4/2Unit (hereinafter referred to as b1 unit) and R₃SiO_1/2It has a unit (R represents a monovalent hydrocarbon group or an alkenyl group) (hereinafter referred to as b2 unit), and has a polystyrene equivalent weight average molecular weight in the range of 1,000 to 8,000. Here, the monovalent hydrocarbon group and the alkenyl group include the same groups as described above in the description of the component (a).
It is preferable that b2 unit / b1 unit in the component (b) = 0.3 to 3, and more preferably 0.7 to 1. The organopolysiloxane having such a resin structure can be synthesized by a well-known method by combining the compounds serving as unit sources at a required ratio and co-hydrolyzing in the presence of an acid, for example. These organopolysiloxanes having a resin structure can be used alone or in combination of two or more.
The blending amount of the component (b) is preferably 5% by mass or more, more preferably 10% by mass, because mechanical properties are obtained and the adhesion is high with respect to the total amount of the components (a) and (b). It is preferably 60% by mass or less, more preferably 40% by mass or less, since the cured product can sufficiently maintain softness. The alkenyl group content in the organopolysiloxane is preferably 0.05 to 0.2 mol / 100 g.
[0012]
The organohydrogenpolysiloxane of the component (c) has at least two, preferably three or more hydrogen atoms bonded to silicon atoms in one molecule, and is used as a crosslinking agent. The organohydrogenpolysiloxane may have a linear, branched, cyclic or three-dimensional network structure. The basic skeleton may be the same as the organopolysiloxane of the component (a) or the component (b), but the organo group does not contain an aliphatic unsaturated bond and is a substituted or unsubstituted monovalent hydrocarbon group. Examples of the component (a) include those described above.
Specific examples of the component (c) include, for example, a methylhydrogensiloxane cyclic polymer, a methylhydrogensiloxane / dimethylsiloxane cyclic copolymer, a methylhydrogensiloxane having a trimethylsiloxy group at both ends of a molecular chain, and trimethyl at both ends of a molecular chain. Siloxy group-blocked dimethyl siloxane / dimethyl hydrogen siloxane copolymer, molecular chain terminal trimethyl siloxy group-blocked methyl hydrogen siloxane / diphenyl siloxane copolymer, molecular chain terminal trimethyl siloxy group-blocked dimethyl siloxane / methyl hydrogen siloxane diphenyl Siloxane copolymer, Dimethyl hydrogensiloxy-capped dimethylpolysiloxane at both molecular ends, Dimethylhydrogensiloxy-capped dimethylpolysiloxane methyl at both molecular terminals Idro siloxane copolymers, both ends of the molecule with dimethylhydrogensiloxy-blocked methylphenylpolysiloxane, and the formula: R '₃SiO_1/2And a siloxane unit represented by the formula: R '₂HSiO_1/2And a siloxane unit represented by the formula: SiO_4/2An organohydrogenpolysiloxane polymer comprising a siloxane unit represented by the formula: R ′₂HSiO_1/2And a siloxane unit represented by the formula: SiO_4/2An organohydrogenpolysiloxane copolymer comprising a siloxane unit represented by the formula: R'HSiO_2/2And a siloxane unit represented by the formula: R'SiO_3/2And / or a formula: HSiO_3/2And an organohydrogenpolysiloxane copolymer comprising a siloxane unit represented by the formula: These organohydrogenpolysiloxanes can be used alone or in combination of two or more.
The amount of component (c) is such that the amount of hydrogen atoms bonded to silicon atoms in component (c) is 0.4 to 10 moles, preferably 0.4 to 1 mole, per mole of all alkenyl groups in the composition. It is an amount that becomes .about.1.5 mol. When the above molar ratio is 0.4 mol or more, the curability is excellent, and when it is 10 mol or less, preferably 1.5 mol or less, the composition does not become too hard and the physical properties do not change with time.
[0013]
In addition, an epoxy group-containing organohydrogenpolysiloxane, an alkoxy group-containing organohydrogenpolysiloxane, an ester siloxane compound, or a silane coupling agent for improving the adhesiveness can be added.
An alkyne alcohol such as 3-methyl-1-butyn-3-ol, an enyne compound such as 3-methyl-3-penten-1-yne, or a curing inhibitor such as benzotriazole is blended to improve handling workability. It does not matter. Further, a surfactant or the like may be appropriately added for wettability to the substrate and defoaming property.
When these additives are added, it is important to add them in small amounts so as not to affect workability and physical properties.
[0014]
The hardness of the plate-shaped main body of the transparent bonding member has sufficient impact relaxation and the like because the impact applied from the transparent substrate side provided on the surface layer is sufficiently mitigated so as not to be largely transmitted to the rigid transparent substrate such as glass. Because of the necessity, the rubber hardness specified in JIS K6301 needs to be 40 ° or less, and when the rubber hardness is lower than 0 °, the penetration specified in JIS K2220 needs to be 20 or less. The smaller the value of the penetration, the harder the numerical value. In general, when the hardness is high, the adhesiveness is inferior, the soft gel state is good, and the influence of stress distortion during processing is small, which is preferable. However, if it is too soft, it is difficult to handle, and the hardness or the penetration must be in the above range.
In order to maintain transparency, the addition of reinforcing fillers should be minimized.However, as long as transparency is not substantially impaired, silica powder surface-treated with organosilane or organosilazane should be added. You may.
[0015]
In the present invention, examples of the rigid transparent substrate to which the transparent substrate is bonded include a large-sized flat display such as a flat-panel CRT, a liquid crystal display, a plasma display, a field emission display, and a projection TV.
In order to increase the adhesive strength of the transparent bonding member to the transparent substrate and / or the rigid transparent substrate, it is preferable that the plate-shaped main body of the transparent bonding member is provided with an adhesive layer on at least one surface.
[0016]
The transparent laminate of the present invention is obtained by laminating a transparent substrate having the above-mentioned optical functional layer, a transparent joining member having a plate-shaped main body made of the above-mentioned polyorganosiloxane plate-like crosslinked product, and a release film in this order. It becomes.
The release film protects the transparent bonding member during production, storage and transportation, and at the time of bonding, peels off the release film and affixes the transparent bonding member to the rigid transparent substrate. Any film can be used as long as it has a release property. Specific examples of the release film include polyethylene resin, polypropylene resin, polypentene resin, polycyclopentene resin, polyethylene terephthalate resin, polyvinyl chloride resin, polystyrene resin, unsaturated polyester resin, fluorine resin, and the like, or these films. A release film coated with a silicone release agent, an olefin release agent, a fluorine release agent, or the like is used. From the viewpoint of cost, it is preferable to use an olefin resin and a release agent.
[0017]
When it is desired to increase the adhesive strength of the transparent joining member to the rigid transparent substrate or the transparent substrate, it is preferable that the transparent joining member is provided with an adhesive layer on at least one surface of the plate-shaped main body. In order to form the pressure-sensitive adhesive layer between the plate-shaped main body and the release film, it is preferable to use a release film having a pressure-sensitive adhesive layer provided on the plate-side main body-side surface of the release film as the release film. preferable. When a release film provided with an adhesive layer is used, when the release film is peeled off, the adhesive layer remains on the plate-shaped main body side, and the transparent bonding member has the adhesive layer. Therefore, the adhesiveness of the transparent joining member to the rigid transparent substrate can be increased.
[0018]
In this case, the pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer is not particularly limited, and any pressure-sensitive adhesive that is usually used as a pressure-sensitive adhesive can be used, such as a copolymer of (meth) acrylate. Examples of the pressure-sensitive adhesive include a rubber-based material such as acrylic resin and polyisoprene, and a thermoplastic elastomer-based main material such as styrene-based thermoplastic elastomer, and a tackifier. An unsaturated aliphatic alkenyl group or silyl group may be introduced into the pressure-sensitive adhesive in order to improve the adhesiveness with the polyorganosiloxane. Further, a nonionic surfactant such as acetylene alcohol may be added to improve the wettability with the polyorganosiloxane.
[0019]
Next, a method for manufacturing a transparent laminate will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing an example of a continuous manufacturing apparatus that can be used in carrying out the manufacturing method of the present invention.
2 and 3 are views showing an embodiment of a sealing portion for sealing between both films at both ends of the film in a direction perpendicular to the running direction.
In the production method of the present invention, first, in a degassing and mixing step, raw materials for producing a crosslinked polyorganosiloxane are degassed and mixed. In FIG. 1, each production material is taken out from each raw material tank 1, 1 'by a transport pump 2, 2', and deaerated by deaerators 3, 3 '. The degassed production raw materials are mixed in the mixer 4 at a predetermined ratio.
[0020]
The above-mentioned components (a), (b) and (c) are preferably used as raw materials for the production of the crosslinked polyorganosiloxane, and these components and (d) a metal white metal catalyst are quantitatively mixed and cast. Leads to.
The platinum group metal-based catalyst (d) promotes the hydrosilylation reaction and is a Group VIII element catalyst. For example, platinum-based powders such as platinum fine powder, platinum black, platinum-supported silica fine powder, platinum-supported activated carbon, chloroplatinic acid, alcohol solutions of chloroplatinic acid, complexes of platinum with olefins, complexes of platinum with alkenylsiloxane, and tetrakis Examples thereof include palladium-based catalysts such as (triphenylphosphine) palladium, rhodium-based catalysts, and thermoplastic resin powders containing these catalysts.
The component (d) is preferably used as an organic solution such as an alcohol solution, from the viewpoint of easy mixing with other liquid raw materials.
It is recommended that the amount of the catalyst be 0.1 to 1,000 ppm based on the weight of the platinum group metal atom with respect to the components (a) and (b).
[0021]
The viscosity of the component (a) is preferably about 50 to 100,000 cP.
Further, the viscosity of the mixed organosiloxane unit of the component (a) and the component (b) is preferably about 100 to 100,000 cP.
The viscosity of the component (c) is preferably from 0.5 to 1,000 cP, since the workability of the resulting composition is good and the physical properties of the crosslinked product are good.
These raw materials may be stored individually, and each component may be mixed at the time of production. However, the components (a) and (b) may be mixed and stored, and at the time of production, this mixed solution may be mixed with ( It is preferable to use a two-pack system in which the component (c) is mixed, since the mixing procedure is simplified. In this case, as is usually the case, the catalyst is provided on the mixed liquid side of (a) and (b), and the curing inhibitor and / or the surfactant is provided on both the mixed liquid (a) and (b) and the liquid (c). May be added.
[0022]
The deaerators 3 and 3 ′ used for deaeration are preferably those that can be continuously operated, and a device using a hollow fiber using a fluororesin for the deaeration membrane, ultrasonic waves under a vacuum, a jet, centrifugal separation, etc. An apparatus or the like which is subdivided and made into a thin film to remove gas from the liquid is used. The concentration of the dissolved gas after degassing is preferably several ppm or less, more preferably 1 ppm or less.
Any mixer can be used as the mixer 4 as long as it can be uniformly mixed, but a static mixer is generally used. In the case of a static mixer, the number of element stages is affected by the viscosity, but is preferably eight or more stages. As a method of improving quantitative performance, a method of adjusting the transport pump while sensing the flow rate can be adopted.
[0023]
On the other hand, the two long films 5, 5 'are respectively unwound from a roll material (not shown), and the two long films 5, 5' are joined at a predetermined interval from a joining point 6 where they are joined. Run with their faces facing each other at an interval of. At least one of the two long films 5, 5 'is the release film described above. The other may be the same release film or a transparent substrate having the above-mentioned optical functional layer. In the case where one is a release film and the other is a transparent substrate having an optical function layer, a transparent laminate of the present invention can be obtained by injecting a raw material for producing a crosslinked polyorganosiloxane between the substrates and crosslinking them. In the case where both are release films, after injecting a raw material for producing a polyorganosiloxane crosslinked product and crosslinking the material between the release films, one of the release films is peeled off and a transparent substrate having an optical functional layer is attached to the release film. The transparent laminate of the present invention is obtained.
When a pressure-sensitive adhesive layer was provided on at least one of the sides of the transparent substrate having the release film and the optical functional layer facing the raw material for producing the polyorganosiloxane crosslinked product, the transparent bonding member and the rigid transparent substrate or the optical functional layer were provided. It is preferable because the adhesive strength with the transparent substrate can be increased.
[0024]
After the junction 6, the gap between both films at both ends of the film in a direction perpendicular to the running direction is sealed to form a sealing portion 9. FIG. 2 shows an example of the sealing portion 9. FIG. 2A is a front view of a film sandwiching a polyorganosiloxane cross-linked material, as viewed from one film side, and FIG. 2B is a cross-sectional view. FIG. 2C is a side view showing the edge of the film. In the method shown in FIG. 2, pinching is performed by a pair of pinch belts 10, 10 ', 10 ", 10"' provided at both ends of each film so as to sandwich the two films. In FIG. 2 (c), the two films are shown as being separated from each other to indicate that they are present. Adhered as shown.
[0025]
FIG. 3 shows that the end portions of the respective films are sealed with a continuous string-shaped packing 12, so that a transparent joining member having a stable thickness up to the end portions and having no optical distortion can be obtained. In other words, the string-shaped packing 12 fed from the packing feeding-out portion 13 is guided by the disc-shaped guides 14, 14 ', 14 ", 14"', and is disposed between the two films at the width direction ends of the films 5, 5 '. To form a sealing portion 9 in close contact with both films.
The string packing 12 is made of a soft or low elastic resin or rubber. Examples of the packing material include polyethylene resin, polyolefin resin and natural rubber. The cross-sectional shape is not particularly limited, but a tube shape is preferable. As the tube, a tube having a free diameter (diameter when no force is applied) having a thickness of 2 to 5 times the thickness T of the transparent joining member and a thickness smaller than 1/2 of T is preferable.
This sealing portion does not need to be sealed in a portion where crosslinking proceeds to such an extent that the raw material does not flow away. When packing is used, it may be collected at the position, roughly outside the heating zone.
[0026]
In the casting process, the degassed and mixed production raw materials are formed by the two long films 5 and 5 ′ and the sealing portion 9 that travel by being injected into the casting port 6 a provided in the junction 6. Filled space.
Inject the production raw material into the casting port 6a at an injection speed such that the liquid reservoir bank 7 is formed, and insert the leading end 15 of the production raw material feed pipe all the way so that air is not entrained when casting the production raw material. By preventing. Adjustment of the bank volume can be stabilized by monitoring and adjusting the flow rate.
Through the merging section 6 of FIG. 1, the two films 5, 5 'are maintained at a predetermined distance between the two films, both ends are sealed, and a raw material for producing a polyorganosiloxane cross-linked material is injected between the two films. It travels between the heating plates 8, 8 '.
As shown in FIG. 1, the gap between the two films whose ends are sealed is widened at the upper part of the confluence part 6 as shown in FIG. The liquid material, which has been reduced to a desired thickness and simultaneously cast, flows without interruption in a direction perpendicular to the machine direction, so that it is filled without entraining air.
[0027]
The thickness of the transparent joining member is regulated by the gap between the pair of heating plates 8 and 8 ′. At this time, the resin pressure applied to the resin between the heating plates is increased, the distortion of the film itself is eliminated, and the surface accuracy of the film is increased. It is preferable to force the surface of the plate so as to have the same surface accuracy. The height of the liquid above the heating plate in FIG. 1 is sufficient, or the distance between the pair of heating plates is increased so that the resin pressure increases as the crosslinking progresses. However, it is desirable that the diameter gradually decreases toward the outlet (the lower part in FIG. 1). When the resin pressure applied to the resin between the heating plates increases, the adhesion between the plate-shaped main body of the obtained transparent joining member and the transparent substrate having the optical functional layer or the pressure-sensitive adhesive layer provided on the release film is improved. It is preferred.
When the pressure of the sealing portion 9 increases with the increase of the resin pressure, the pressing force of the pinch belts 10, 10 'in FIG. 2 is increased, or the disc-shaped guides 14, 14 as shown in FIG. It is desirable to reinforce the string-like packing 12 with ', guide slides 15, 15' or the like.
[0028]
When the resin pressure between the heating plates 8 and 8 'is increased, friction with the film is increased, and the film is easily deformed or scratched. Therefore, as shown in FIG. It is preferable that the film and the polyorganosiloxane are transported between the belts 16 and 16 ′ running at the same speed as the film. In this case, as shown in FIG. 4, a heating plate 8 is provided on the opposite side of the belt 16 from the film side, and the polyorganosiloxane can be crosslinked by heating through the belt. Oil for lubrication may be included between the belt 16 and the heating plate 8. Instead of a heated plate, a backup roll may be applied to heat the entire atmosphere.
The heating temperature varies depending on the heat resistance of the film, the crosslinking conditions of the liquid material, and the line speed, but is preferably 60 ° C. or less, more preferably 40 ° C. or less, for crosslinking without distortion. The heating method can be arbitrarily selected, such as a normal electric heater, hot air, or a heat medium. By this heating, the polyorganosiloxane is cross-linked while being sandwiched between both running films.
[0029]
Although the above description has been made with reference to the manufacturing apparatus of the type in which the film runs from top to bottom, as shown in FIG. 5, it may be a horizontal type apparatus. In the horizontal type apparatus, the lower film 5 is caused to travel horizontally or slightly downward, and the upper film is bent at the junction 6 by 90 ° or more to form a bank at the junction. When a horizontal apparatus is used, the viscosity of the liquid material is preferably about 10,000 to 100,000 cP in consideration of air entrainment and casting.
[0030]
The transparent bonding member formed by being sandwiched and crosslinked by two kinds of films is taken out and cut into a predetermined shape as necessary.
Although not shown in the drawing, a mechanism for picking up the transparent joining member employs a generally used pinch roll method, belt conveyor method, or the like. The take-off speed, which is the line speed, depends on the crosslinking speed, the length of the heated portion, and the like, but is approximately 0.3 to 5 m / min. If necessary, a completely crosslinked state can be obtained by performing post-curing after the cutting step. As a method of cutting into a predetermined shape, a slit method using a rotary blade or a fixed blade, or a normal method such as Victoria punching is used. In this case, since the transparent joining member is a sticky member, it is preferable that the blade is subjected to a non-adhesive process such as a fluorine treatment.
In addition, in order to prolong the pot life of the mixed liquid material, cooling the piping and the like, attaching two types of film dust removing devices, taking measures against static electricity, filtering the liquid material Needless to say, the clean booth of the entire apparatus can be appropriately performed as needed.
[0031]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples.
(Example 1)
Using the apparatus shown in FIG. 1 having the sealing portion shown in FIG. 3 and the belt shown in FIG. 4, the temperature of the heating plate was set to 45 ° C., and as a long film, an acrylic film as an optical function was used as an antireflection film. A layer (a total thickness of 50 μm) of an acrylic film and a urethane film having a layer (manufactured by Asahi Glass, product name: Cytop, about 10 μm in thickness) and a 50 μm polyester terephthalate film with a silicone release agent (a product of Shin-Etsu Chemical Co., Ltd.) , X-70-201) was run on a release film coated with 1 μm, and the following liquid polyorganosiloxane was cast between the two films, crosslinked to a thickness of 1.8 mm, and a size of 800 mm × 1,000 mm. A transparent joining member free from defects such as optical distortion and bubbles was prepared. In this case, the interval between the heating plates was reduced by 1.5 mm from the inlet to the outlet. The silicone release film was peeled off and adhered to a glass of the same size having a thickness of 5 mm with a vacuum press to form an antireflection layer on the glass surface. The increase in haze value from the state without the transparent joining member was 0.3%. The test pattern printed on the back of the glass was placed, and the test pattern was observed from a 45-degree angle. Was no problem. The surface has moderate elasticity, 4mm²100g / mm for presser with area of²After pressing with a load of 1 minute, it was opened for 10 minutes, and the state of the dent was confirmed, but no trace was observed.
A 1 kg iron ball was dropped from 1 m above, but the glass plate was not broken. The adhesive strength of the transparent bonding member to glass was 0.9 kg at a width of 25 mm and a peel of 180 °.
After this transparent bonding member was crosslinked by heating at 150 ° for 4 hours, the hardness was measured by the method specified in JIS K6301 and the penetration was measured by the method specified in JIS K2220. The hardness was 0 ° or less. And the penetration was 15.
[0032]
(Polyorganosiloxane composition used)
60 parts of dimethylpolysiloxane having a viscosity of 5,000 cP and having both ends terminated by vinyldimethylsiloxy groups,_4/250 mol% unit, (CH₃)₃SiO_1/2Unit 42.5 mol%, CH₂= CH (CH₃)₂SiO_1/240 parts of a vinylmethylpolysiloxane having a resin structure consisting of 7.5 mol% units, and 5.3 parts of a copolymer of methylhydrogensiloxane and dimethylsiloxane capped with a trimethylsiloxy group (a hydrogen atom bonded to a silicon atom) Was mixed with 0.3 parts by mole per the total amount of the vinyl groups) and 0.05 part (5 ppm in terms of platinum metal) of a modified solution of chloroplatinic acid in dodecyl alcohol (1 part by weight of platinum metal).
[0033]
(Example 2)
1.5 mm in thickness and 800 mm in size in the same manner as in Example 1 except that the same polyorganosiloxane as in Example 1 was cast between two silicone release films similar to those used in Example 1. A transparent bonding member of × 1,000 mm was prepared. The two silicone release films were peeled off and adhered to a laminated film of the same size glass and an acrylic film and a urethane film having the same fluorine-based antireflection layer as used in Example 1 by a vacuum press device. An antireflection layer was formed on the glass surface via a transparent bonding member.
The optical and mechanical properties of the transparent joining member with an antireflection layer were almost the same as in Example 1, and were satisfactory.
[0034]
(Example 3)
Using the apparatus used in Example 1, a laminated film (total thickness 210 μm) of an acrylic film and a urethane film having a fluorine-based antireflection layer (manufactured by Asahi Glass Co., Ltd., Cytop, product name: about 10 μm) as an optical function on the acrylic film ) And a 100 μm-thick polyethylene film having a 25 μm-thick transparent acrylic pressure-sensitive adhesive (manufactured by Soken Chemical Co., Ltd., SK Dyne) on the surface thereof, so that the pressure-sensitive adhesive faces the urethane film side. The following liquid polyorganosiloxane was cast between the films and crosslinked to form a transparent joining member having a thickness of 2.5 mm, a size of 900 mm × 1200 mm and having no defects such as optical distortion and bubbles. The polyethylene film of the transparent bonding member was peeled off, and the surface of the acrylic pressure-sensitive adhesive was adhered to 5 mmt glass of the same size with a vacuum laminator to form an antireflection layer on the glass surface via the transparent bonding member. The increase in the haze value from the state without the transparent joining member was 0.5%, and the test pattern was observed in the same manner as in Example 1.
The surface had moderate elasticity, and after being pressed against a pressing element having an area of 4 mm2 with a load of 80 g / mm2 for 1 minute, it was opened for 10 minutes and a dent state was confirmed, but no trace was observed. A 1 kg iron ball was dropped from 1 m above, but the glass plate was not broken. The adhesive strength of the transparent joining member to glass was 1.1 kg at a width of 25 mm and a peel of 180 °.
After heating and cross-linking the transparent joining member at 150 ° for 4 hours, the hardness was measured and measured by the method specified in JIS K6301 and found to be 20 °.
[0035]
(Polyorganosiloxane composition used)
70 parts of dimethylpolysiloxane having a viscosity of 70,000 cP and having both ends blocked by vinyldimethylsiloxy groups,_4/250 mol% unit, (CH₃)₃SiO_1/2Unit 42.5 mol%, CH₂= CH (CH₃)₂SiO_1/230 parts of a resin-structured vinylmethylpolysiloxane composed of 7.5 mol% units and 2.6 parts of a copolymer of methylhydrogensiloxane and dimethylsiloxane capped with a trimethylsiloxy group (a hydrogen atom bonded to a silicon atom) Was mixed with 0.65 mol of the total amount of the vinyl groups) and 0.05 part (1 part by weight of platinum metal) of a chloroplatinic acid-modified dodecyl alcohol solution (5 ppm in terms of platinum metal).
[0036]
(Example 4)
1.2 mm in thickness in the same manner as in Example 3 except that the same polyorganosiloxane as in Example 3 was cast between two polyethylene films with an acrylic pressure-sensitive adhesive similar to those used in Example 3. A transparent joining member having a size of 900 mm × 1200 mm was prepared. The polyethylene film of the transparent bonding member was peeled off, and the polyethylene film of the same size and a laminated film having the same fluorine-based antireflection layer as used in Example 3 were adhered by a vacuum laminator, and the antireflection layer was bonded to the transparent bonding member. And formed on the glass surface.
The optical and mechanical properties of the transparent joining member with an antireflection layer were almost the same as in Example 3 and were satisfactory.
[0037]
【The invention's effect】
The transparent joining member of the present invention has excellent transparency, has no optical distortion, and has excellent impact relaxation. Therefore, when a transparent substrate having an optical function layer is attached to a large display such as a flat-panel CRT using this transparent bonding member, a predetermined optical function can be given to the display without causing transparency or distortion. In addition, since it has a shock absorbing ability, the shock applied to the display can be further reduced.
The transparent laminate of the present invention can impart a desired optical function to a rigid transparent substrate such as a display without substantially lowering the transparency and without causing optical distortion, and furthermore, it is possible to obtain an impact resistance. Can be absorbed, making it more secure.
According to the production method of the present invention, a transparent laminate having a uniform thickness, no optical distortion, a desired optical functional layer, and excellent shock absorbing ability can be continuously obtained with high production efficiency. Can be.
[Brief description of the drawings]
FIG. 1 is a schematic partial sectional view showing an example of a continuous production apparatus for a transparent laminate.
FIG. 2 is a schematic view of a main part showing one embodiment of a sealing part.
FIG. 2A is a front view of a film having a polyorganosiloxane sandwiched therebetween, as viewed from one film side.
FIG. 2B is a sectional view.
FIG. 2C is a side view showing the edge of the film.
FIG. 3 is a schematic view of a main part showing another embodiment of a sealing portion.
FIG. 4 is a schematic cross-sectional view of a main part showing one embodiment of a heating plate part.
FIG. 5 is a schematic cross-sectional view of another example of an apparatus for continuously producing a transparent laminate, which is a Western dance.
[Explanation of symbols]
5, 5 ': long film, 6: merging section, 8, 8': heating plate, 9: sealing section

Claims (8)

A bonding member having a transparent plate-shaped main body and bonding a transparent substrate having an optical function layer and a rigid transparent substrate, wherein the plate-shaped main body is made of a cross-linked polyorganosiloxane having a thickness of 1 to 5 mm. And a rubber hardness specified in JIS K6301 is 40 ° or less, and when the rubber hardness is 0 ° or less, a penetration specified in JIS K2220 is 20 or less. . The crosslinked polyorganosiloxane,
(A) a diorganopolysiloxane containing two or more alkenyl groups bonded to a silicon atom in one molecule,
(B) An organopolysiloxane R ₃ SiO _{1/2 having} a resin structure comprising a SiO _4/2 unit having at least one alkenyl group bonded to a silicon atom in one molecule and a unit represented by the following formula:
(Wherein, R represents a monovalent hydrocarbon or alkenyl group)
(C) an organohydrogenpolysiloxane having two or more hydrogen atoms bonded to a silicon atom in one molecule,
The transparent joining member according to claim 1, comprising a structural unit derived from The transparent bonding member according to claim 1, wherein an adhesive layer is provided on at least one surface of the plate-shaped main body. A transparent laminate comprising a transparent substrate having an optical function layer, the transparent joining member according to any one of claims 1 to 3, and a release film laminated in this order. a) degassing and mixing the raw materials for producing the crosslinked polyorganosiloxane;
b) From the junction where two long films, at least one of which is a release film, are joined at a predetermined interval, the two long films are run facing each other at a predetermined interval from each other. The space formed by the two running long films and the sealing portion formed by sealing the two films at both ends in the film width direction is filled with the degassed and mixed poly. A casting step of injecting the production raw material of the organosiloxane cross-linked product from the junction while forming a bank of the production raw material at the junction;
5. The method according to claim 4, further comprising the step of: c) cross-linking the polyorganosiloxane by passing both films running with the raw material for producing the cross-linked polyorganosiloxane between the heating plates. A method for producing a transparent laminate. 6. The method according to claim 5, wherein one of the long films is a release film and the other is a transparent substrate having an optical functional layer. 7. The method according to claim 5, wherein an adhesive is provided on an inner surface of at least one of the long films. The manufacturing method according to any one of claims 5 to 7, wherein the sealing portion is caused to run together with the film with a continuous string-shaped packing inserted in a gap between the films.

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