JP2000158465A - Continuous manufacture of cured resin sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for continuously manufacturing a cured resin sheet usable also for an optical application. SOLUTION: The method for continuously manufacturing a cured resin sheet comprises the steps of adhering a narrow tape 4 on an easily releasable resin layer 2 provided on a continuous support 1, developing a curable resin-containing liquid 5 in a sheet-like state, curing 6 the developed layer, and releasing and recovering 8 the formed cured sheet 7 together with the resin layer from the support through the tape 4. Thus, the cured resin sheet 9 formed with the tap 4 can be efficiently released and recovered without crack or residual strain from an interface between the easily releasable resin layer 2 and the support 1. The surface state of the support 1 is satisfactorily transferred and reflected with the layer 2, and the sheet having excellent optical characteristics can be easily obtained with a mirror surface, a protrusion and recess surface or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for continuously producing a cured resin sheet having excellent optical characteristics.

[0002]

2. Description of the Related Art Conventionally, as a continuous production method of a sheet made of a thermoplastic resin, there has been known a casting method in which a solution of a thermoplastic resin is spread in a sheet form on a continuous support such as an endless belt. However, when such a casting method is applied to a curable resin, there is a problem that a formed cured sheet adheres to a support, and cracks and residual strains occur when the cured sheet is peeled and collected. Was difficult to obtain.

[0003]

An object of the present invention is to develop a manufacturing method capable of continuously obtaining a cured resin sheet which can be used for optical applications.

[0004]

According to the present invention, a narrow tape is adhered onto an easily peelable resin layer provided on a continuous support, and a curable resin-containing liquid is spread in a sheet form. It is intended to provide a continuous method for producing a cured resin sheet, wherein the cured layer is subjected to a curing treatment, and the formed cured sheet is peeled and collected together with the resin layer from the support through the narrow tape.

[0005]

According to the present invention, the cured resin sheet formed through the narrow tape is efficiently peeled off from the interface between the easily peelable resin layer and the support without cracks or residual strain, and collected. Thus, the surface state of the support can be transferred and reflected favorably through the resin layer, and a sheet having excellent optical properties via a mirror surface, an uneven surface, or the like can be easily obtained.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The production method according to the present invention comprises a step of adhering a narrow tape to an easily peelable resin layer provided on a continuous support, and developing a curable resin-containing liquid into a sheet. Then, the spread layer is subjected to a curing treatment, and the formed cured sheet is peeled and collected together with the resin layer from the support through the narrow tape to continuously obtain a cured resin sheet. FIG. 1 shows an example of the manufacturing process. 1 is a continuous support, 2 is an easily peelable resin layer, 4 is a narrow tape, 5 is a sheet-like spread layer of a curable resin-containing liquid, 6 is a curing treatment device, 7 is a cured resin sheet, and 8 is a cured resin sheet. It is a peeling means.

In the illustrated example, a continuous support made of the endless belt 1 is interposed between a driving drum 11 and a driven drum 12, for example, from 0.1 to 10 m / min, preferably from 0.2 to 10 m / min.
While rotating in the direction of the arrow at a constant speed such as 5 m / min,
A resin liquid 22 is applied thereon via a die 21 and dried, or, if necessary, cured by heating or light irradiation to form an easily peelable resin layer 2. In the illustrated example, an ultraviolet irradiation device 3 is provided for the purpose of curing treatment.

Next, a narrow tape 4 is adhered on the formed continuous resin layer 2 while continuously forming an easily peelable resin layer on the support 1 as described above. In the illustrated example, while the narrow tape 4 is continuously supplied from the take-up reel 41, the tape is adhered to both ends in the width direction of the continuous resin layer 2 in the forming direction (the direction of the arrow) via the pressure roll 42. It has become.

Next, a curable resin-containing liquid 5 is applied via a die 51 onto a continuous resin layer to which the narrow tape is adhered, and is developed into a sheet. The developed layer 5 is heated or irradiated with light. The cured sheet 7 formed by curing through an appropriate curing treatment device 6 such as the above is peeled and recovered from the support 1 by the peeling means 8 via the narrow tape 4 together with the resin layer 2 and the cured resin sheet 9 Are continuously manufactured.

In the present invention, as the support, an appropriate continuous body such as the above-mentioned endless belt which can support the spread layer of the curable resin-containing liquid and maintain it in a sheet shape can be used. The material forming the support may be any material that can withstand the curing treatment of the curable resin, and therefore may be a suitable material such as a metal such as stainless steel, copper or aluminum, ceramic or plastic. Particularly, stainless steel is preferable from the viewpoint of durability and the like.

The surface of the support is formed into an appropriate shape such as a mirror surface, a flat surface, a prism surface, or a fine uneven surface according to the sheet to be formed, such as a liquid crystal cell substrate, an antireflection sheet, a prism sheet or a diffusion sheet. And there is no particular limitation. When the purpose is to produce a mirror-cured cured resin sheet, it is preferable to use a support having a surface roughness Ra of 0.02 μm or less. Further, it is preferable to form the resin layer or the cured sheet on a support that is as horizontal as possible, rather than obtaining a sheet having excellent thickness accuracy.

In forming the resin layer provided on the support, it is preferable to use an appropriate resin which does not adhere to the support or which has a low adhesive strength even if adhered and can be easily peeled off from the support. Yes, there is no particular limitation. Incidentally, examples of the resin according to, urethane-based resin and acrylic resin, polyester-based resin and polyvinyl alcohol, polyvinyl alcohol-based resin such as ethylene vinyl alcohol copolymer,
Examples thereof include vinyl chloride resins and vinylidene chloride resins.

Further, polyarylate resin, sulfone resin, amide resin, imide resin, polyether sulfone resin, polyetherimide resin, polycarbonate resin, silicone resin, fluorine resin, polyolefin resin, styrene A resin, a vinylpyrrolidone resin, a cellulose resin, an acrylonitrile resin, and the like can also be used for forming the resin layer. In forming the resin layer, a blend of two or more kinds of appropriate resins may be used.

From the viewpoint of easy releasability from a stainless steel support, urethane resins, particularly those represented by the following chemical formula, are preferred.

Further, since the resin layer can be peeled off together with the formed cured sheet and function as a surface coat layer of the cured resin sheet, for example, chemical resistance, surface hardness, optical anisotropy, low water absorption, low The material can be selected for the purpose of imparting functions such as gas barrier properties such as moisture permeability and low oxygen permeability.

Accordingly, the resin layer has an easy peeling property, for example, as a superposed layer in which a polyvinyl alcohol-based resin layer for the purpose of imparting a gas barrier property is provided on a urethane-based resin layer for the purpose of imparting an easy peeling property. In addition, it may be formed as a multi-layered product in addition to a single-layered product for the purpose of imparting other functions.

The resin layer is formed by, for example, forming a solution of the resin in an appropriate solvent such as an organic solvent or water as required, and applying a roll coating method, a spin coating method, a wire bar coating method, an extrusion coating method, or a curtain coating method. Or a suitable method such as spray coating, dip coating, or the like, applying it to a predetermined surface of the support, drying it as necessary, and curing it by a method such as heat treatment or light irradiation depending on the resin. Can be carried out by forming a film by an appropriate method.

In the case of the above-mentioned coating method, it is preferable that the resin liquid is adjusted to 1 to 100 centipoise for uniform coating. In the case of coating on an endless belt by the above-mentioned casting method, a method by an extrusion coating method is preferable from the viewpoint of coating efficiency and the like, and in that case, a resin liquid prepared particularly at 1 to 10 centipoise can be preferably used. . When a coating layer of a urethane resin or the like is cured by light irradiation, it is preferable to use a high-pressure or low-pressure ultraviolet lamp having a center wavelength of 365 nm or 254 nm from the viewpoint of processing efficiency and the like.

The thickness of the resin layer to be formed can be appropriately determined. In general, the thickness is 1 to 10 μm, preferably 8 μm or less, particularly 2 to 5 μm, based on each layer unit forming the resin layer, from the viewpoint of easy peelability and prevention of occurrence of cracks during peeling. Is preferred.

The narrow width tape adhered on the coating layer facilitates the integrated peeling and recovery of the formed cured resin sheet, that is, the superimposed body of the resin layer and the cured sheet, and also causes cracks and plastic deformation during the peeling. The purpose is to prevent the occurrence of As the narrow tape, an appropriate tape can be used, and there is no particular limitation. Therefore, the width of the tape can be appropriately determined according to the width of the sheet to be manufactured and the like. However, since the tape portion is usually cut into a loss, a width of 5 to 50 mm is appropriate from the viewpoint of suppressing the loss and the like. It is.

The material of the narrow tape can also be determined according to the curing method of the curable resin. For example, an appropriate material made of the above-mentioned polymer or metal foil in the resin layer can be used. When the curable resin is cured by a thermosetting method, a narrow tape capable of withstanding the curing temperature, for example, PET having a heat resistance temperature of 150 ° C. or more, particularly 180 ° C. or more
Polyester, fluorine, polyimide, aromatic polyamide, sulfone, polyethersulfone, polyetherimide, polycarbonate, etc. polymers and metal foils are used.

Although the arrangement position and the number of the narrow tapes can be appropriately determined, the end of the resin layer 2 in the width direction as illustrated in FIG. It is preferable to provide the narrow tape 4 continuously on one side or both sides of the portion in the forming direction of the cured resin sheet 9.

In particular, when the sheet is provided on both sides of the width direction end as shown in the figure, it is possible to reinforce the end which is liable to crack when peeled off, and to prevent the occurrence of cracks in the effective portion of the sheet. it can. In addition, by using a method of lifting it through a narrow tape and separating and collecting it, the cured resin sheet, especially,
It is possible to avoid the peel recovery force directly acting on the cured sheet, and prevent the plastic recovery from occurring in the effective portion of the cured sheet or the like with the release recovery force, thereby obtaining a sheet having excellent smoothness and uniform optical characteristics. be able to.

Therefore, from the above-mentioned point, the narrow tape is protruded from the end of the resin layer for the purpose of gripping the narrow tape, that is, the resin tape is not interposed between the end of the narrow tape and the support. It may be arranged.

The adhesion of the narrow tape to the resin layer can be achieved based on the adhesive force and the fusion force of the resin layer. However, from the viewpoint of the reliability of the adhesive force and the like, the adhesive system via the adhesive layer is used. Is preferred. An appropriate adhesive can be used as the adhesive, but an adhesive treatment via an adhesive layer is preferable from the viewpoint of simplicity of the adhesive treatment. For forming the pressure-sensitive adhesive layer, for example, an appropriate pressure-sensitive adhesive such as acrylic, rubber, or silicone can be used, and there is no particular limitation. By providing an adhesive layer on the narrow tape in advance, the adhesive treatment can be easily performed via a pressure roll or the like.

At least a curable resin is used for preparing the curable resin-containing liquid to be spread on the resin layer, but the curable resin is not particularly limited, and may be selected according to the purpose of use of the cured resin sheet to be formed. Accordingly, a suitable material such as an epoxy-based, acrylic, urethane-based, acrylurethane-based, silicone-based or polyester-based thermosetting or ultraviolet curable material can be used.

When excellent heat resistance and optical characteristics are required, such as when used in a liquid crystal display device, an epoxy-based curable resin is preferably used, and such a resin is also used as an adhesive. The present invention can be advantageously applied to such excellent adhesive strength.

Examples of the epoxy-based curable resin include bisphenol A type and bisphenol F type.
Bisphenol type such as bisphenol S type and hydrogenated type thereof, novolak type such as phenol novolak type and cresol novolak type, nitrogen-containing ring type such as triglycidyl isocyanurate type and hydantoin type, alicyclic type and aliphatic type, Examples include aromatic type such as naphthalene type, glycidyl ether type, low water absorption type such as biphenyl type, dicyclo type, ester type, ether ester type, and modified types thereof. Above all, bisphenol A type, alicyclic type and triglycidyl isocyanurate type are less likely to discolor and can be preferably used for optical applications.

For the preparation of the curable resin-containing liquid, one or two
More than one kind of curable resin can be used, and if necessary, a curable resin and an appropriate curing agent according to the curing method can be used. Incidentally, for the epoxy-based curable resin described above, for example, organic acid-based compounds, amine-based compounds, amide-based compounds and hydrazide-based compounds, imidazole-based compounds and imidazoline-based compounds, phenol-based compounds And urea compounds, polysulfide compounds and acid anhydride compounds. One or more curing agents can be used.

Further, in preparing the curable resin-containing liquid, a curing accelerator, an antioxidant, a modifier, a surfactant, a dye or a pigment, a dye or pigment, which may be added to the cured resin as required. One or two or more appropriate additives such as an agent and an ultraviolet absorber may be blended.

The curable resin-containing liquid can be prepared by mixing the components with a solvent, if necessary, so that the components can be fluidized and developed. Therefore, in order to spread the curable resin-containing liquid, an appropriate method capable of flowing the curable resin-containing liquid and forming the sheet into a sheet shape according to the above-described resin layer forming method such as a curtain coating method or a roll coating method. Can be adopted. In particular, in the casting method, the extrusion coating method can be preferably applied from the viewpoint of coating efficiency and the like.

In the above, when the curable resin-containing liquid is spread in the form of a sheet on the resin layer to which the narrow tape is adhered, a case where the narrow tape is provided at the end of the resin layer is exemplified in FIG. It is more preferable to form the spreading layer 5 (7) so that the curable resin-containing liquid also reaches the narrow tape 4 at the end as described above, from the viewpoint of easily achieving peeling and collecting.

The curing treatment of the spread layer of the curable resin-containing liquid formed on the resin layer can be performed by an appropriate method depending on the curable resin such as a heat-curable type or an ultraviolet-curable type. The curing treatment usually forms a cured resin sheet in which the resin layer and the cured sheet adhere well and can be handled integrally.

The thickness of the cured sheet formed in the above can be appropriately determined according to the purpose of use of the cured resin sheet and the like. Generally, it is 1 mm from the point of taking advantage of the characteristics of a sheet such as rigidity, flexibility, thinness and lightness.
Hereinafter, it is preferably 30 to 900 μm, particularly 100 to 800 μm. For optical applications, a thickness of 100 to 500 μm is often advantageous.

The cured sheet after the curing treatment is peeled and collected from the support via a narrow tape adhered on the resin layer. An appropriate method such as a method in which the tape portion is gripped and lifted, the formed resin cured sheet 9 is peeled off from the support, and the recovered resin sheet 9 is collected.

In the above, achieving a balanced flexibility for preventing the occurrence of cracks and cracks due to peeling and plastic deformation and residual strain, and obtaining a cured resin sheet excellent in uniformity of optical characteristics having a small phase difference, etc. Rather, it is preferable to peel off at a glass transition temperature of the cured sheet and a temperature range lower by 20 ° C. than that. The glass transition temperature is determined by thermomechanical analysis at a heating rate of 5 ° C./min and in a tensile mode.

The recovered cured resin sheet in a continuous state can be collected and cut into appropriate dimensions through appropriate cutting means such as a laser beam, an ultrasonic cutter, dicing, or a water jet, or a winding method. Where possible, it can be performed by an appropriate method such as a winding and collecting method.

According to the method according to the invention as described above,
The production speed can be easily controlled by adjusting the moving speed of the spreading layer through the support, and the thickness of the sheet obtained by adjusting the moving speed and the spreading amount can be easily controlled. Further, a cured resin sheet or the like having an uneven structure such as a mirror surface or a prism array structure can be formed via the surface shape of the support.

The cured resin sheet according to the present invention can be preferably used for various applications based on the advantages of the cured resin and the like, and can be used as an optical sheet such as a liquid crystal cell substrate, an antireflection sheet, a prism sheet or a diffusion sheet. It can be preferably used. The cured resin sheet that has been peeled off may be further subjected to a curing treatment, if necessary, depending on the purpose of use or the like, so that the glass transition temperature is higher than at the time of peeling.

[0040]

Example 1 A 17% by weight toluene solution of a urethane-based UV-curable resin was discharged from a die by the casting method shown in FIG.
m / min is cast on a stainless steel endless belt that rotates and runs at a constant speed, and after toluene is volatilized and dried, it is cured through an ultraviolet irradiation device and is 500 mm in width and 2 μm in thickness.
After forming a resin layer of width 19 mm on both ends in the width direction
The rubber-based heat-resistant adhesive tape using the PET base material was sequentially and continuously bonded via a pressure roll.

Next, while continuing the above operation, the curable resin-containing liquid is discharged from the die at a rate of 100 g / min onto the cured resin layer, and is formed into a sheet-like shape within the range over the rubber-based heat-resistant adhesive tape. The cast layer is spread and the spread layer is passed through a heating device.
Heat-curing treatment at 20 ° C for 30 minutes to obtain glass transition temperature of 1
After setting the cured sheet at 20 ° C., the cured sheet is separated from the endless belt together with the resin layer adhered to the cured sheet by a method of lifting a rubber-based heat-resistant adhesive tape through a peeling mechanism arranged on a driving drum adjusted to a temperature of 110 ° C. Peel off,
It is cut at intervals of 490 mm in the flow direction and with both ends including a rubber-based heat-resistant adhesive tape, and has a width of 450 mm, an average thickness of 400 μm (standard deviation of 23 μm) and excellent uniformity of the optical properties of the smooth surface. A resin sheet was obtained continuously.

[0042] In addition, the said curable resin containing liquid is 3, 4- of the said chemical formula.
Epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate 400 parts (parts by weight, the same applies hereinafter), methylhexahydrophthalic anhydride 500 parts, tetra-n-butylphosphonium o, o-diethylphosphorodithioate 15 of the following chemical formula Parts, 9 parts of glycerin and 1 part of a surfactant were stirred and mixed, and the mixture was aged at 49 ° C. for 90 minutes to adjust the viscosity.

The average thickness and the standard deviation are 45
It was determined by measuring 60 points in a 0 mm square plane. When the cured resin sheet obtained above was cured at 170 ° C. for 1 hour, the glass transition temperature could be increased to 180 ° C.

[Brief description of the drawings]

FIG. 1 is an explanatory side view of an example of a manufacturing process.

FIG. 2 is a cross-sectional view of a cured resin sheet.

[Explanation of symbols]

1: support (endless belt) 2: resin layer 4: narrow tape 5: spread layer of curable resin-containing liquid 6: curing device 7: cured sheet 8: peeling means 9: cured resin sheet

Continuing from the front page (72) Inventor Shuzo Fujiwara 1-2-1, Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Yoshimasa Sakata 1-2-1, Shimohozumi, Ibaraki-shi, Osaka Nitto Denko F term (reference) 4F205 AA36 AA39 AA42 AA44 AC03 AC05 AD05 AG01 AG03 AG23 AH73 AM32 AR06 GA07 GB02 GB11 GB13 GB16 GB26 GB27 GC07 GE02 GE25 GE27 GF01 GF06 GF24 GN08 GN22 GN24 GN28 GN29

Claims (5)

[Claims] 1. A narrow-width tape is adhered onto an easily peelable resin layer provided on a continuous support, and a curable resin-containing liquid is spread in a sheet form to cure the spread layer. A method for continuously producing a cured resin sheet, wherein the cured sheet thus formed is peeled and collected together with the resin layer from the support via the narrow tape. 2. The narrow tape according to claim 1, wherein the resin layer comprises a single layer or a multilayer having a thickness of 1 to 10 μm based on a layer unit, or a width of 5 to 50 mm and a heat resistance temperature of 150 ° C. or more. A continuous manufacturing method in which a resin layer is bonded in a forming direction and on one or both sides of an end in a width direction thereof. 3. The continuous production method according to claim 1, wherein the cured sheet is separated at a glass transition temperature and a temperature range lower by 20 ° C. than the glass transition temperature. 4. The continuous production method according to claim 1, wherein the curable resin is an epoxy resin. 5. The continuous production method according to claim 1, wherein the resin layer is made of a urethane-based resin.