TW201801951A - Flexographic printing plate and manufacturing method thereof, and manufacturing method of liquid crystal display element which is less liable to adhere foreign matters to the plate surface and to have the plate surface stuck to a surface to be printed such as an electrode forming surface - Google Patents

Abstract

This invention provides a flexographic printing plate and manufacturing method thereof, and manufacturing method of liquid crystal display element. The flexographic printing plate comprises an ink transfer layer made of a cured product of a photo-curable resin composition and having one side as a plate surface, of which a plate surface adhesive force is set to be 1.4 N or less and a Type A durometer hardness is set to be A58 or less. The manufacturing method is a method making a resin composition whose composition has been adjusted to satisfy the above characteristics performed with curing reaction by irradiation with an actinic ray in a layered state while being in contact with a roughened mold surface; and then, peeled off from the mold surface. A method for manufacturing a liquid crystal display element includes a step of forming a liquid crystal alignment film by flexographic printing using the flexographic printing plate.

Description

Flexible printing plate and manufacturing method thereof, and manufacturing method of liquid crystal display element

The present invention relates to a flexible printing plate and a method for manufacturing the same, and a method for manufacturing a liquid crystal display element. The method for manufacturing the liquid crystal display element includes forming a liquid crystal alignment film of a liquid crystal display element by flexible printing using the flexible printing plate. step.

In order to form a liquid crystal alignment film having such a high film quality as to have a uniform thickness, no pinholes, and the like as thin as possible on the electrode formation surface of the substrate constituting the liquid crystal display element, flexible printing is used.

In the flexographic printing, a flexographic printing plate including a flat-shaped ink transfer layer containing a sheet of a soft resin and having a state in which the ink serving as the basis of the liquid crystal alignment film is mounted on the surface is used. The electrode forming surface, such as the electrode forming surface, is in contact with the printing surface, and is formed so as to transfer the held ink to a plate surface on the printing surface.

In order to improve the wettability to the ink, the ink can be held well, and the held ink can be well transferred to the surface to be printed. The plate surface is usually a rough surface having a predetermined surface roughness.

The ink transfer layer having a roughened surface of the plate is produced through the following steps using a photocurable resin that undergoes a curing reaction by irradiation with actinic rays (Patent Document 1 and the like).

In other words, if the photocurable resin is applied to a roughened sheet having a roughened surface formed into a roughened surface, the hardened reaction is performed by irradiation with actinic rays such as ultraviolet rays. When the roughened sheet is peeled off, an ink transfer layer is formed, and a rough surface shape is transferred to a surface of the ink transfer layer that is in contact with the profile of the roughened sheet, and the surface is formed to be roughened. Surface.

Then, the corresponding portion of the formed ink transfer layer is thermally or mechanically cut off to form an engagement portion or a chuck hole for mounting on a printing machine, or if necessary, the surface of the plate and the printing pattern are not The area corresponding to the printing area is removed thermally or mechanically, thereby manufacturing a flexible printing plate.

In addition, if the photocurable resin is subjected to a curing reaction in a state in which a reinforcing sheet such as a polyester sheet is superposed on the opposite surface of the layer of the photocurable resin, it is possible to produce a laminated body integrally formed on the opposite surface. A flexible printing plate of the reinforcing sheet.

As the photocurable resin which is the basis of the ink transfer layer, for example, a prepolymer having a 1,2-polybutadiene structure and an ethylenic double bond at the terminal, and a reactive diluent having 1 in one molecule can be suitably used. A mixture of an ethylenically unsaturated single body having one or two ethylenic double bonds, a photopolymerization initiator, and the like (Patent Document 2 and the like). [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2013-119179 [Patent Document 2] Japanese Patent Laid-Open No. 2012-242683

[Problems to be Solved by the Invention] According to the photocurable resin described in Patent Document 2, an ink transfer layer having moderate rubber elasticity and flexibility and excellent solvent resistance can be formed.

However, since the ink transfer layer including a cured product of a conventional photocurable resin described in Patent Document 2 and the like generally has high adhesion (tackiness), the manufactured flexographic printing plate is used for flexographic printing. At the time of storage or the like, there is a problem that foreign matter other than debris or dust of the dried and solidified ink is easily adhered to the exposed surface of the ink transfer layer, that is, the surface of the plate.

In addition, when a flexible printing plate having foreign matter adhered to the surface of the plate is used as it is to form a liquid crystal alignment film, the following disadvantages occur frequently: a film blank where no film is formed or a film is formed even in a portion where the foreign matter is attached, The thickness also becomes non-uniform; as a result, there is a concern that the productivity of the liquid crystal display element is significantly reduced.

Therefore, usually, for example, at the beginning or end of printing, or every predetermined number of printing, the following operations must be frequently repeated: the flexible printing plate is detached from the plate body of the printing machine, and the solvent is washed, Allow it to dry and reattach it to the plate body.

However, in particular, a large flexible printing plate corresponding to a recent large-scale liquid crystal display element has a large printing plate having a side of, for example, more than 1500 mm. In order to cover the entire surface of the large flexible printing plate surface without leaving tiny foreign matters It is not easy to densely wash to all corners, and it is difficult to completely eliminate the problems such as film blank.

In addition, the operation of removing the flexographic printing plate from the plate body for washing or mounting on the plate body after washing is also difficult, and there are also concerns such as bending or scarring due to operation errors. Defects, the quality of the flexographic printing plate is reduced, and the productivity of the liquid crystal display element is decreased.

In addition, due to some failures during printing, the ink supply is delayed, and the adhesion of the ink to the surface of the plate is partially reduced. If the flexible printing plate is directly contacted on the electrode formation surface of the substrate constituting the liquid crystal display element, it still exists. There is a concern that the flexible printing plate is attached to the electrode formation surface as it is.

If the flexographic printing plate is attached, there is a concern that the substrate may be broken or damaged by being lifted together when the plate body is moved, or an anilox roll for supplying ink to the flexographic printing plate. It is broken by contact with the lifted or broken substrate.

In addition, when these problems occur, it is necessary to remove a damaged substrate, an anilox roll, or the like, which causes a major failure that requires the printing step to be stopped for a long period of time, and there is a concern that the productivity of the liquid crystal display element is significantly reduced.

An object of the present invention is to provide a flexographic printing plate and a method for manufacturing the flexographic printing plate which are difficult to cause adhesion of foreign matter to the surface of the printing plate, or adhesion of the printing plate surface to a printed surface such as an electrode forming surface, and the like, and to form a liquid crystal by using the flexible printing plate. The alignment film is a method of manufacturing a liquid crystal display element that can improve the productivity of a liquid crystal display element compared to the current situation. [Technical means to solve the problem]

The present invention is a flexible printing plate including a flat-plate ink transfer layer, the ink transfer layer containing a cured product of a photocurable resin composition and formed on one side as a plate surface. The adhesive force obtained by a probe tack test is 1.4 N or less, and the hardness of the A-type durometer of the ink transfer layer is A58 or less.

In addition, the present invention is the method for manufacturing a flexographic printing plate of the present invention, which includes: adjusting the basis of the ink transfer layer based on the adhesion of the plate surface and the rubber hardness of the ink transfer layer. A step of composing the resin composition; making the resin composition into a layered state while in contact with the roughened surface, and performing a curing reaction by irradiation with actinic rays to form the ink conversion A step of printing a layer; and a step of peeling the ink transfer layer from the mold surface, and forming a surface of the ink transfer layer in contact with the mold surface as a roughened plate surface.

Furthermore, the present invention is a method for manufacturing a liquid crystal display element, which includes the step of forming a liquid crystal alignment film by flexible printing using the flexible printing plate of the present invention. [Effect of the invention]

According to the present invention, it is possible to provide a flexographic printing plate and a method for manufacturing the flexographic printing plate which are difficult to cause foreign matter to adhere to the plate surface, or the plate surface to be adhered to a printed surface, and to form a liquid crystal alignment film by using the flexible printing plate. A manufacturing method of a liquid crystal display element which improves the productivity of a liquid crystal display element compared with the present situation.

<< Flexible Printing Plate >> As described above, the flexographic printing plate of the present invention includes a flat ink transfer layer including a cured product of a photocurable resin composition and formed on one side. The surface of the plate is an adhesive force (adhesiveness) obtained by a probe initial adhesion test of the plate surface of 1.4 N or less, and the hardness of the A-type durometer of the ink transfer layer is A58 or less.

According to the present invention, by setting the adhesive force on the surface of the plate to the range described above, not only can foreign matter be prevented from adhering to the surface of the plate, but even the plate surface of a large flexographic printing plate can be easily removed by washing. Foreign matter, up to its various corners, can suppress the generation of film blanks or uneven thickness caused by the adhesion of foreign matter, as compared with the current situation.

In addition, since the number of times of washing can be reduced compared to the current situation, it is possible to reduce the chance of defects such as bending or scarring caused by work errors, and to suppress the deterioration of the quality of the flexographic printing plate.

In addition, during printing, even if the flexographic printing plate is in direct contact with the printed surface such as the electrode forming surface of the substrate, it is possible to prevent the substrate or the anilox roller from being attached as it is.

Therefore, according to the flexible printing plate of the present invention, these effects are combined with each other, and the productivity of the liquid crystal display element can be improved more than the current situation.

Considering that the effect is further improved, it is more preferable that the adhesion force on the surface of the plate is smaller within the range, and it is desirable to set it to 0 N in terms of the effect.

However, according to the inventor's research, the reason why the surface of the plate has adhesiveness is the low molecular weight component contained in the ink transfer layer containing the cured product of the resin composition. The lower the low molecular weight component, the more the plate can be reduced. Adhesion on the surface, but at the same time, new problems arise in that the rubber hardness of the ink transfer layer increases, the flexibility decreases, and the printing characteristics of the flexographic printing plate decrease.

On the other hand, according to the present invention, by setting the hardness of the A-type durometer of the ink transfer layer to the above range, it is possible to suppress a decrease in the flexibility of the ink transfer layer and to maintain good printing characteristics of the flexographic printing plate.

In addition, in the present invention, an adhesion tester HTC-1 manufactured by Toyo Seiki Seisakusho Co., Ltd. based on the probe preliminary adhesion test method is used to indicate that the probe preliminary adhesion test passes the value obtained by the following method. The resulting adhesion of the surface.

That is, in a state where the flexographic printing plate for measuring the adhesive force is fixed on a plate body of φ50 mm with the surface of the plate as the outside, the temperature is 23 ° C and the relative humidity is 50%, at a temperature of 4.9 N. After the contact of the adhesion tester was brought into close contact with the surface of the plate for 10 seconds, the load was peeled off at a peeling speed of 30 mm / min, and the maximum load at the time of peeling was measured at 10 locations on the surface of the plate. The average of the results is used as the adhesion of the surface of the plate.

In addition, the hardness of the A-type durometer of the ink transfer layer is measured according to the Japanese Industrial Standard JIS K6253-3: 2012 "Vulcanized Rubber and Thermoplastic Rubber-Method for Determining Hardness-Part 3: Hardness Tester Hardness", In a temperature of 23 ° C and a relative humidity of 50%, the value displayed after the pressure plate was brought into contact with the test piece for 15 seconds is shown.

<< Resin Composition >> The photocurable resin composition that is the basis of the ink transfer layer includes, for example, a polyfunctional containing a photocurable resin and a trifunctional or higher functionality having reactivity with the photocurable resin. Resin composition of sexual components and the like.

According to the resin composition, at the time of curing reaction of a photocurable resin by irradiation with actinic rays, the photocurable resin is subjected to a cross-linking reaction with a polyfunctional component, thereby reducing the causes of adhesion. The proportion of low molecular weight components can reduce the adhesion of the surface of the plate.

The blending ratio of the polyfunctional component per 100 parts by mass of the photocurable resin is preferably 1 part by mass or more, and preferably 4 parts by mass or less.

If the blending ratio of the polyfunctional component is less than this range, there is a concern that the effect brought about by blending the polyfunctional component, that is, the photo-curable resin is subjected to a crosslinking reaction to reduce the surface of the plate Adhesive effect, and the adhesion of the surface of the plate exceeds the range of 1.4 N or less, it is easy to cause various problems such as the adhesion of foreign matter or the washing to remove it, or the sticking of the printed surface. Attach various problems caused.

On the other hand, when the blending ratio of the polyfunctional component is out of the above range, there is a concern that the photocurable resin excessively undergoes a cross-linking reaction, and the rubber hardness of the ink transfer layer exceeds the range below A58, The printing characteristics of the flexographic printing plate are degraded. In addition, in particular, as described above, in the case of the reinforcing sheet of the opposite area of the ink transfer layer, there is a concern that the flexographic printing plate has a large warpage due to the shrinkage of the ink transfer layer during the curing reaction. song.

In contrast, by setting the blending ratio of the polyfunctional component to the above range, not only the rubber hardness or flexibility of the ink transfer layer can be maintained in a good range, but also warpage of the flexographic printing plate can be suppressed, and The adhesiveness of the surface of the plate is reduced well, and it is difficult to cause various problems such as adhesion of foreign matter, adhesion to the surface to be printed, and the like.

In addition, in consideration of further improving the effect, the blending ratio of the polyfunctional component is particularly preferably within the above range and is set to 3 parts by mass or less per 100 parts by mass of the photocurable resin.

Incidentally, when the photocurable resin contains a solvent that does not participate in the curing reaction and is removed from the film by drying, the blending ratio of the polyfunctional component is only to remove the solvent from the total amount of the photocurable resin. The amount of the solid content (the photocurable resin itself) of the amount may be set to the range as a reference (100 parts by mass).

<Photocurable resin> As the photocurable resin, any of a variety of conventionally known photocurable resins for forming an ink transfer layer can be used.

In particular, when it is considered to form an ink transfer layer having moderate rubber elasticity and flexibility and excellent solvent resistance, the photocurable resin is preferably used as described above, and will have a 1,2-polybutadiene structure and A prepolymer having an ethylenic double bond at the terminal, an ethylenically unsaturated monolith having one or two ethylenic double bonds in one molecule as a reactive diluent, and a photopolymerization initiator are respectively prescribed. The ratio is made by.

(Prepolymer) As the prepolymer constituting the photocurable resin, any of a variety of prepolymers having a 1,2-polybutadiene structure and having a polymerizable ethylenic double bond at the terminal can be used. The prepolymer is, for example, (a) a hydrogenated 1,2-polybutadiene compound having a terminal hydroxyl group, and (b) the (a) hydrogenated 1,2-polybutadiene compound using a diisocyanate. Among the compounds obtained by chain extension, at least one terminal of a compound is synthesized by introducing at least one polymerizable ethylenic double bond or the like. Among these, the number of terminal hydroxyl groups per molecule of the hydrogenated 1,2-polybutadiene compound of (a) is preferably 1.2 or more, particularly preferably 1.5 or more, and preferably 2.0 or less.

When the number of terminal hydroxyl groups is smaller than this range, there is a concern that sufficient mechanical strength cannot be imparted to the flexographic printing plate.

The hydrogenated 1,2-polybutadiene compound is preferably a hydrogenated compound having 50% or more of the side chain vinyl group of the 1,2-polybutadiene structure.

If the hydrogenation rate is less than 50%, there is a concern that the elasticity of the rubber of the flexographic printing plate is reduced, or the printing characteristics are reduced by being hardened.

Examples of the hydrogenated 1,2-polybutadiene compound include at least one of a hydrogenated product of poly-1-butene and a hydrogenated product of 1,2-polybutadiene.

Among these, 1,2-polybutadiene may contain cis-1,4 body and trans-1,4 body as a fine structure, but its content rate is preferably 50% or less.

The hydrogenated 1,2-polybutadiene compound (a) can be synthesized, for example, by any of the methods described below. -A method in which butadiene is subjected to living anionic polymerization, ethylene oxide is added thereto, a hydroxyl group is introduced at a terminal, and a vinyl group in a side chain is hydrogenated. -A method of polymerizing butadiene by using a metal salt such as NaPdCl ₄ , KPdCl ₄ , NH ₄ PdCl ₄ , and PdBr ₂ as a polymerization initiator, introducing a hydroxyl group at a terminal, and then hydrogenating a vinyl group at a side chain.・ Using a peroxide or azo compound having a hydroxyl group in a molecule such as a third butyl-β-hydroxyethyl peroxide, 4,4'-azobis-4-cyano-n-pentanol as a polymerization initiator A method for free radical polymerization of 1-butene.

In addition, the compound of (b), which is obtained by subjecting the hydrogenated 1,2-polybutadiene compound of (a) to chain extension with a diisocyanate, preferably has two or more urethane bonds per molecule. And preferably 20 or less.

This is because there is a tendency that as the number of urethane bonds increases, the rubber elasticity of the flexographic printing plate increases, but the solvent resistance decreases.

On the other hand, when the number of urethane bonds is in the above range, a flexographic printing plate having excellent balance between rubber elasticity and solvent resistance can be obtained.

Ethylene is introduced into the end of (a) hydrogenated 1,2-polybutadiene compound and / or (b) compound (hereinafter, (a) (b) may be collectively referred to as "prepolymer precursor") As a method of synthesizing a prepolymer with a double bond, for example, any of the following methods can be adopted. -A diisocyanate is reacted with a hydroxyl group of a prepolymer precursor to introduce a terminal diisocyanate group, and reacts with a compound containing an ethylenic double bond and a group having an active hydrogen. -A carboxyl group is introduced into the terminal of the prepolymer precursor to react with an epoxy compound having an ethylenic double bond.

In addition, in the case where the compound of (b) is used as a prepolymer precursor, it is excessive by using the terminal hydroxyl group of the hydrogenated 1,2-polybutadiene compound (a) as the basis. Diisocyanate can also introduce a terminal diisocyanate group at its terminal while the chain is extended.

The chain extension reaction can be carried out in the presence of a urethane catalyst such as a tertiary amine or a tin compound. However, it is also possible to perform a chain extension reaction in the absence of a urethane catalyst.

The reaction temperature is not particularly limited, but is preferably 40 ° C or higher, and preferably 100 ° C or lower.

The reaction of synthesizing a prepolymer by using a urethanization reaction of a terminal diisocyanate group and a group having an active hydrogen and introducing an ethylenic double bond into a prepolymer precursor can be performed under the same conditions. In this case, it is preferable that an appropriate polymerization inhibitor is present.

Examples of the compound containing an ethylenic double bond and an active hydrogen group used in the urethanation reaction include: hydroxyalkylene (meth) acrylate, polyalkylene glycol mono (meth) acrylate One or two or more of (meth) acrylic secondary aminoalkylene esters, N-monosubstituted acrylamide, unsaturated carboxylic acids, and the like.

Specific examples of the compound include, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, and polypropylene glycol. Mono (meth) acrylate, polybutylene glycol mono (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolethane di (meth) acrylate, tetramethylol Methane tri (meth) acrylate, dibromo neopentyl glycol mono (meth) acrylate, glycerol di (meth) acrylate, hydroxycyclohexyl (meth) acrylate, (meth) acrylate monomethyl Ethylaminoethyl, N-methyl (meth) acrylamide, N-octyl (meth) acrylamide, acrylic acid, methacrylic acid, itaconic acid monoester, fumaric acid monoester, One or two or more kinds of maleic acid monoester, glycidyl (meth) acrylate, and the like.

Examples of the diisocyanate include one or two or more of an aliphatic diisocyanate, a diisocyanate of an alicyclic compound, and an aromatic diisocyanate.

Specific examples of the diisocyanate include hexamethylene diisocyanate (HMDI), ω, ω'-diisocyanate-1,3-dimethyl crude benzene, and 2,6- Toluene diisocyanate and / or 2,4-toluylene diisocyanate (TDI), terephthalylene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate (MDI), hydrogenated 2,6-TDI and One or two or more of hydrogenated 2,4-TDI, hydrogenated MDI, dicyclohexyldimethylmethane diisocyanate, and lysine isocyanate.

The average molecular weight of the prepolymer is represented by the number average molecular weight Mn, and is preferably 1,000 or more, and preferably 30,000 or less.

When the number average molecular weight Mn is less than this range, there is a concern that the rubber elasticity of the flexographic printing plate becomes insufficient. In addition, when it exceeds the above range, there is a concern that the viscosity of a resin composition containing a photocurable resin as a main component becomes large, and its fluidity or followability to a molding surface and reproducibility of a rough surface are reduced.

(Ethylene Unsaturated Monomer) An ethylenically unsaturated monoton is one having one or two ethylenic double bonds in one molecule and functioning as a reactive diluent as described above, as the ethylene Specific examples of the unsaturated unsaturated monomer include, for example, vinylpyridine, N-vinylcarbazole, (meth) acrylic acid or an ester thereof, (meth) acrylamide or a derivative thereof, styrene, ethylene Toluene, divinylbenzene, diallyl phthalate, vinyl acetate, acrylonitrile, itaconic acid, fumaric acid, maleic anhydride, maleic acid, and One or two or more kinds of monoalkyl esters and dialkyl esters.

Examples of the (meth) acrylic acid ester include alkyl, cycloalkyl, tetrahydrofurfuryl, allyl, glycidyl, hydroxyalkyl mono (meth) acrylate, and alkyl Mono (meth) acrylates or di (meth) acrylates of diols, polyoxyalkylene glycols (such as polypropylene glycol dimethacrylate, etc.), mono (meth) acrylates of trimethylolpropane or One or two or more of di (meth) acrylate, mono (meth) acrylate, di (meth) acrylate, etc. of pentaerythritol.

Further, examples of the derivative of (meth) acrylamide include N-hydroxymethyl (meth) acrylamide, N, N'-alkylenebis (meth) acrylamide, and diacetone (formaldehyde) Group) One or two or more kinds of acrylamide.

In addition, octyl, decyl, nonyl, decyl, lauryl, ceryl and other mono (meth) acrylates having 8 to 30 carbon atoms (such as lauryl methacrylate), Glycols with 4 to 30 carbon atoms, such as 1,3-butanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and 1,18-stearyl glycol Mono (meth) acrylate or di (meth) acrylate (for example, 1,3-butanediol dimethacrylate, etc.) is particularly effective for improving the solvent resistance of a flexographic printing plate.

The ethylenically unsaturated monolith is preferably used in combination of two or more kinds according to the characteristics required for the flexographic printing plate.

The ethylenically unsaturated monomer can be prepared at a ratio of 5 parts by mass to 100 parts by mass based on 100 parts by mass of the prepolymer.

In particular, if it is considered to reduce the viscosity of a resin composition containing a photocurable resin as a main component, to improve its fluidity or followability to a molding surface, to reproduce the rough surface, or to improve the printing characteristics of a flexographic printing plate, etc., It is preferable to mix | blend in the ratio of 40 mass parts or more and 60 mass parts or less. When two or more kinds of ethylenically unsaturated monobasic bodies are used in combination, the blending ratio is a ratio of the total amount thereof to 100 parts by mass of the prepolymer.

(Photopolymerization Initiator) As the photopolymerization initiator, for example, benzoin alkyl ether or the like can be used. Examples of the benzoin alkyl ether include one or two or more of benzoin diethyl ether, benzoin-n-propyl ether, and benzoin isobutyl ether.

The photopolymerization initiator can be prepared at a ratio of 0.001% by mass or more and 10% by mass or less of the total amount of the prepolymer and the ethylenically unsaturated monomer. In particular, in order to obtain an optimum light-receiving speed for forming an ink transfer layer by irradiation with actinic rays, it is preferably formulated in a ratio of 0.01% by mass or more and 5% by mass or less within the above range.

<Polyfunctional component> As the polyfunctional component constituting the resin composition together with the photocurable resin, any of a plurality of trifunctional compounds having three or more groups having a reactive group with the photocurable resin may be used. One.

The polyfunctional component having reactivity with, for example, the photocurable resin described in the foregoing paragraph is preferably selected from trifunctional or higher monomers, oligomers, and prepolymers having three or more ethylenic double bonds in one molecule. At least one of the group consisting of polymers, the photocurable resin includes a prepolymer having a 1,2-polybutadiene structure and an ethylenic double bond at the terminal, and a The ethylenically unsaturated singly having one or two ethylenic double bonds in the molecule, and a photopolymerization initiator.

Examples of the polyfunctional component include pentaerythritol triacrylate, trimethylol propane triacrylate (A-TMPT), di-trimethylolpropane tetraacrylate, and ethoxylated pentaerythritol tetraacrylate. One or two or more tri-functional compounds such as pentaerythritol tetraacrylate, dipentaerythritol polyacrylate, dipentaerythritol hexaacrylate, trimethylol propane trimethacrylate (TMPT), and the like.

Among them, A-TMPT and / or TMPT having excellent reactivity with a photocurable resin is preferred, and TMPT is particularly preferred.

The blending ratio of the polyfunctional component is preferably 1 part by mass or more, and preferably 4 parts by mass or less, and particularly preferably 3 parts by mass or less per 100 parts by mass of the total amount of the photocurable resin. The reason is as explained above.

<Other components> In the resin composition containing the photocurable resin and the polyfunctional component, a plurality of types may be blended in order to adjust the viscosity, the rubber elasticity or strength of the flexographic printing plate, the solvent resistance, or the weather resistance. additive.

Examples of the additives include softeners such as dioctyl phthalate, process oil, and liquid paraffin, or liquid rubber (butyl rubber, butadiene rubber, styrene butadiene rubber, and nitrile). Rubber, etc.), antioxidants, thermal polymerization inhibitors, etc.

<Flexible printing plate and its manufacturing method> The flexographic printing plate of the present invention includes, for example, an ink transfer layer containing a cured product of the resin composition, and the adhesive force obtained by the probe initial adhesion test as described above is 1.4. N or less, and the A-type hardness tester hardness of the ink transfer layer is set to A58 or less.

Therefore, the flexibility of the ink transfer layer can be maintained in a good range, warpage of the flexographic printing plate can be suppressed, and the adhesion of the surface of the printing plate can be reduced, which makes it harder for foreign matter to adhere to the current situation. Or attaching to the printed surface, and various problems associated with it.

In addition, in consideration of further improving the effect, the adhesive force on the surface of the plate is preferably 0.7 N or less, and particularly preferably 0.4 N or less within the above range. The hardness of the A-type durometer of the ink transfer layer is preferably A53 or less, and particularly preferably A50 or less within the above range.

The lower limit of the adhesive force is 0 N as described above. That is, although the surface of the plate does not have adhesiveness, it is preferable in terms of preventing the occurrence of film blanks, unevenness in thickness, and the like caused by adhesion of foreign matter.

In addition, if it is considered that the durability of the ink transfer layer is improved, or the rubber elasticity is increased so that sinking is difficult to occur, the A-type durometer hardness of the ink transfer layer is preferably A20 or more within the above range.

The flexographic printing plate of the present invention is produced by using the resin composition described above by the production method of the present invention.

Specifically, a resin composition is first prepared by adjusting the blending ratio of the polyfunctional component within the range according to the adhesive force required for the plate surface and the rubber hardness required for the transfer layer.

In addition, the resin composition may be prepared by preparing a polyfunctional component at the same time as the photocurable resin, or may be prepared by adding a polyfunctional component to the prepared photocurable resin as described above.

Especially in the latter case, there is an advantage that the current flexographic printing plate manufacturing steps are not significantly changed, and a flexographic printing plate whose adhesive force and rubber hardness are controlled can be provided according to customer requirements and the like.

Next, a soft roughened sheet having a profile corresponding to the rough surface shape of the plate surface is set on a solid platen such as a glass plate, and a resin containing a photocurable resin and a polyfunctional component is supplied thereto. A composition, and if necessary, a reinforcing sheet or the like is superimposed thereon, in a state where the resin composition is formed into a layer of a certain thickness, actinic rays such as ultraviolet rays are irradiated to perform a curing reaction and a crosslinking reaction, and then The roughened sheet was peeled.

In this way, the rough surface shape is transferred on the surface that is in contact with the profile of the roughened sheet, and an ink transfer layer is formed on the surface that becomes the roughened plate surface. When a reinforcing sheet is superimposed, the reinforcing sheet is integrated with the ink transfer layer.

Then, the corresponding portion of the formed ink transfer layer is thermally or mechanically cut off to form an engagement portion or a chuck hole for mounting on a printing machine, or if necessary, the surface of the plate and the printing pattern are not The area corresponding to the printing area is removed thermally or mechanically, thereby manufacturing the flexible printing plate of the present invention.

<< Method for Manufacturing Liquid Crystal Display Element >> The present invention is a method for manufacturing a liquid crystal display element, which includes the step of forming a liquid crystal alignment film by flexible printing using the flexible printing plate of the present invention.

According to the present invention, by using the flexographic printing plate of the present invention whose surface surface has reduced adhesiveness compared with the current situation, it is possible to prevent problems caused by adhesion of foreign matter or washing to remove it, or to prevent damage to the substrate. In the case of various problems caused by the printing surface adhesion, etc., forming a liquid crystal alignment film can improve the productivity of a liquid crystal display element.

The other steps of the manufacturing method of the present invention can be carried out in the same manner as before. That is, after a transparent electrode layer corresponding to a predetermined matrix pattern is formed on a surface of a transparent substrate such as a glass substrate, a liquid crystal alignment film is formed by flexible printing using the flexible printing plate, and the liquid crystal is aligned by friction or the like as necessary. The surface of the film is subjected to alignment processing to produce a substrate.

Next, two substrates were prepared, in a state where the respective transparent electrode layers were aligned, liquid crystal materials were sandwiched between the gaps and fixed to each other to form a laminated body, and polarizing plates were further provided on both outer sides of the laminated body as necessary. Thus, a liquid crystal display element is manufactured.

The configuration of the present invention is not limited to the examples described above, and various changes can be made without departing from the gist of the present invention. [Example]

<Example 1> (Resin composition)-Preparation of photocurable resin: Polybutadiene (number average molecular weight Mn = 3000), TDI (mixture of 2, 4 and 2, 6 bodies), and The 2-hydroxypropyl (meth) acrylate was reacted to synthesize a prepolymer having a 1,2-polybutadiene structure and a number average molecular weight Mn = 15,000 having an ethylenic double bond at the terminal.

Next, a total of 100 parts by mass of the prepolymer was blended with lauryl methacrylate, 1,3-butanediol dimethacrylate, and polypropylene glycol dimethacrylate as ethylene unsaturated monomers. 50 parts by mass and 2.3 parts by mass of benzoin isobutyl ether as a photopolymerization initiator were used to prepare a photocurable resin. • Preparation of resin composition To 100 parts by mass of the photocurable resin, 1 part by mass of TMPT as a polyfunctional component was prepared to prepare a resin composition having photocurability.

(Flexible printing plate) ・ Roughened sheet Roughened sheet is a sheet formed of a urethane-based thermoplastic elastomer having a PET film laminated on its back surface as a reinforcing film [ The exposed surface of Silklon (registered trademark) SNESS80-100 μm manufactured by Okura Industry Co., Ltd. was embossed using an embossing roller to form a roughened profile.・ Manufacture of flexographic printing plates

In a state where the roughened sheet is fixed on a smooth and transparent glass plate with the profile as the upper surface, the resin composition just prepared is supplied to the profile, and PET as a reinforcing sheet is superposed thereon. Sheet, and in a state where the resin composition is applied and diffused into a layered layer of a certain thickness, ultraviolet rays are irradiated to perform a curing reaction and a crosslinking reaction to form an ink transfer layer, and then the roughened sheet is peeled off, and the ink is transferred The surface of the printed layer in contact with the molding surface is used as a roughened plate surface to manufacture a flexible printing plate.

<Comparative Example 1> A resin composition was prepared in the same manner as in Example 1 except that TMPT was not blended as a polyfunctional component, and a flexographic printing plate was produced.

<Example 2 to Example 4 and Comparative Example 2 Except that the blending ratio of TMPT, which is a polyfunctional component, was set to 2 parts by mass per 100 parts by mass of the photocurable resin (Example 2), 3 Except for parts by mass (Example 3), 4 parts by mass (Example 4), and 5 parts by mass (Comparative Example 2), a resin composition was prepared in the same manner as in Example 1 to produce a flexographic printing plate.

<Example 5 to Example 8, Comparative Example 3> A-TMPT was used instead of TMPT as a polyfunctional component, and the blending ratio of this A-TMPT was set per 100 parts by mass of the photocurable resin. Except for 1 part by mass (Example 5), 2 parts by mass (Example 6), 3 parts by mass (Example 7), 4 parts by mass (Example 8), and 5 parts by mass (Comparative Example 3). The resin composition was prepared in the same manner as in Example 1 to produce a flexographic printing plate.

<Adhesion measurement> As described above, the adhesion tester HTC-1 manufactured by Toyo Seiki Seisakusho Co., Ltd. based on the probe initial adhesion test method was used to determine the production in each of the examples and comparative examples by the following methods. Of the surface of a flexographic printing plate.

That is, the flexible printing plate (10 mm in width) manufactured in each of the Examples and Comparative Examples was fixed to the plate body of φ50 mm with the double-sided tape as the outer surface of the plate. In the above state, under the environment of a temperature of 23 ° C. and a relative humidity of 50%, the contactor of the adhesion tester was brought into close contact with the surface of the plate under a load of 4.9 N for 10 seconds, and the contact pressure was 30 mm / min. The peeling speed was peeled off, and the maximum load at the time of peeling was measured at 10 locations on the plate surface, and the average value of the results was determined as the adhesion force on the plate surface.

Next, the adhesion on the surface of the plate was evaluated on the following criteria. ：: Adhesive strength is 0.4 N or less. Extremely good. (Circle): Adhesion exceeds 0.4 N and is 0.7 N or less. good. Δ: Adhesive force exceeds 0.7 N and is 1.4 N or less. Normally. ×: Adhesion exceeds 1.4 N. bad.

<Rubber hardness measurement> According to the Japanese Industrial Standard JIS K6253-3: 2012 "Vulcanized rubber and thermoplastic rubber-Method for determining hardness-Part 3: Hardness tester hardness", the temperature is 23 ° C and the relative humidity is In a 50% environment, the pressure plate was brought into contact with the test piece for 15 seconds, and then the hardness of the A-type durometer of the ink transfer layer of the flexographic printing plate manufactured in each example and comparative example was read.

Next, the rubber hardness of the ink transfer layer was evaluated based on the following criteria. ：: The hardness of the A-type hardness tester is A50 or less. Extremely good. ○: The hardness of the A-type durometer exceeds A50 and is A53 or less. good. Δ: The hardness of the A-type durometer exceeds A53 and is A58 or less. Normally. ×: The hardness of the A-type durometer exceeds A58. bad.

<Warpage evaluation> The warpage immediately after manufacture of the flexographic printing plates produced in each of the examples and comparative examples was evaluated on the basis of the following criteria. ：: No warpage was observed at all. Extremely good. (Circle): Although the curvature was seen a little, it was eliminated if it was left still on a flat plate for a while. good. (Triangle | delta): Although the curvature was seen, and it was not completely eliminated even if it left still for a while on a flat plate, it can be used for flexible printing. Normally. ×: The warpage is large and cannot be used for flexible printing. bad.

<Comprehensive evaluation> Regarding the score of each evaluation, ◎ is 5 points, ○ is 3 points, △ is 1 point, and × is 0 points. Adhesion and rubber hardness are important items, and the scores are squared. Then, the product of the scores of each evaluation was obtained, and comprehensive evaluation was performed based on the following criteria. ：: The score is 1,000 or more. Extremely good. ○: The score is 100 or more and less than 1000 points. good. Δ: The score is 1 or more and less than 100 points. Normally. ×: The score is less than 1 point. bad. The above results are shown in Tables 1 and 2.

[Table 1]

[Table 2]

Judging from the results of Examples 1 to 8 and Comparative Examples 1 to 3 in Tables 1 and 2, the prepolymers having a 1,2-polybutadiene structure and having an ethylenic double bond at the end were included. In a combination of a photocurable resin having an ethylenically unsaturated monomer and a photopolymerization initiator, and a polyfunctional component having an ethylenic double bond, the ratio of the photocurable resin per 100 parts by mass of the photocurable resin is 1 The polyfunctional component is blended in a proportion of at least 4 parts by mass to form a flexographic printing plate having a plate surface with an adhesive force of 1.4 N or less and an A-type durometer hardness of the ink transfer layer of A58 or less.

In addition, judging from the results of Examples 1 to 8, if it is considered to further improve the effect, the blending ratio of the polyfunctional component is preferably 3 parts by mass or less within the range, and the polyfunctional component is preferably A-TMPT and / or TMPT are particularly preferably TMPT.

no

no

no

Claims (5)

A flexible printing plate includes a flat plate-shaped ink transfer layer, the ink transfer layer includes a hardened body of a photocurable resin composition, and is formed on one side as a plate surface. The adhesion obtained by the adhesion test was 1.4 N or less, and the hardness of the A-type durometer of the ink transfer layer was A58 or less. The flexographic printing plate according to item 1 of the scope of patent application, wherein the resin composition forming the ink transfer layer includes: a photocurable resin; and a trifunctional or more functional resin having reactivity with the photocurable resin. The polyfunctional component is 1 to 4 parts by mass per 100 parts by mass of the photocurable resin. The flexographic printing plate according to item 2 of the scope of patent application, wherein the photocurable resin comprises: a prepolymer having a 1,2-polybutadiene structure and having an ethylenic double bond at the terminal; One or two ethylenically unsaturated monoliths with ethylenic double bonds, and a photopolymerization initiator, and the polyfunctional component is selected from monomers having three or more ethylenic double bonds in one molecule, and oligosaccharides. At least one of a group consisting of a polymer and a prepolymer. A method for manufacturing a flexographic printing plate, which is the method for manufacturing a flexographic printing plate according to any one of items 1 to 3 of the scope of patent application, comprising: according to the adhesion of the surface of the printing plate, and the ink A step of adjusting the rubber hardness of the transfer layer to adjust the composition of the resin composition that is the basis of the ink transfer layer; and layering the resin composition while contacting the roughened surface In a state where the hardening reaction is performed by irradiation with actinic rays to form the ink transfer layer; and the ink transfer layer is peeled from the molding surface to separate the ink transfer layer from the surface of the ink transfer layer. The step of forming the surface in contact with the mold surface into a roughened plate surface. A method for manufacturing a liquid crystal display element includes the step of forming a liquid crystal alignment film by flexible printing using the flexible printing plate according to any one of claims 1 to 3 of a patent application range.