KR20060092065A - Cleaning sheet with excellent blocking resistance and cleaning method of screen printing plate using the same - Google Patents

Abstract

The cleaning sheet of the present invention is a cleaning sheet obtained by irradiating an electron beam of 1 to 50 Mrad to at least one surface of a single layer sheet containing a resin, and has a specific value for (i) solvent absorption amount and (ii) storage modulus. It is characterized by.

According to the cleaning sheet of the present invention, the object can be reliably cleaned without damaging or contaminating the object to be cleaned. Moreover, according to the cleaning sheet of this invention, the blocking of sheets when it rolls up in roll shape alone is prevented effectively, the feeding of the sheet | seat from a roll is improved, and the ease of handling and operability in roll shape are further improved. You can.

Description

Cleaning sheet with excellent blocking resistance and cleaning method of screen printing plate using the same}

1 is an image diagram of a 90 ° peel force measurement.

[Description of the code]

1: substrate 3: fixed side test piece

5: Movable side test piece 7: Roughness of test piece overlapping surface and back surface

Patent Document 1: Japanese Patent No. 3280367

Patent Document 2: Japanese Patent No. 3281323

Patent Document 3: Japanese Patent Application No. 2004-065826

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning sheet excellent in blocking resistance, particularly a cleaning sheet wound in a roll shape that is very suitable for cleaning a screen printing plate used for screen printing, and a screen printing plate cleaning method using the cleaning sheet.

Recently, liquid crystal displays (LCDs) and plasma display panels (PDPs) have emerged as displays, and their demands continue to increase.

The PDP encloses a rare gas, nitrogen, or the like in a single or mixed gas state and supplies a voltage to a discharge region sandwiched between two opposing glass substrates with electrodes, so that gas discharge is generated at the intersection of the thin wire electrodes arranged vertically and horizontally. It is a self-luminous display which emits visible light by exciting the fluorescent material for R (red), G (green), and B (blue) applied to each cell with the ultraviolet-ray generated by this.

The layer of phosphor material is generally formed by printing a phosphor ink paste by a screen printing method between the ribs and the ribs of the substrate on which the ribs are formed.

However, in the case of printing the phosphor ink paste by this screen printing method, the ink paste returns to the back side of the screen printing plate (abutment to the to-be-printed object) and adheres as ink paste dregs, so that in the next printing, the ink paste dregs are applied to the to-be-printed matter. There have been problems such as transfer adhesion, inferior printing accuracy, blurring of printing boundary, and the like.

In the color LCD, a color filter formed by separately disposing a dye layer on an insulating substrate in a planar manner is used. Various methods are known as a method of forming the dye layer of this color filter, and as one example thereof, there is a printing method of printing inks of three primary colors of R, G, and B on a substrate. As one of the printing methods, the screen printing method is used. In this case, the same problem as that of the above-described PDP is easily generated.

As a method of removing the ink paste debris adhered to the back surface of the screen printing plate, a method of scraping mechanically, a method of wiping with a cloth or paper using a solvent, a method of sticking and sticking an adhesive sheet and the like are known.

Among these, the method using an adhesive sheet is considered to be inferior to the screen printing plate, and does not cause excessive mechanical damage, and it is thought that the printing defect by a tickle or dust derived from a cloth or paper does not generate | occur | produce, among these methods. Various adhesive sheets are proposed as an adhesive sheet using (see patent document 1, patent document 2).

However, in the method using such an adhesive sheet, when the cleaning operation on the back of the screen printing plate is repeated, a part of the adhesive is peeled off from the substrate and attached to the screen printing plate, or the screen printing plate is stretched and deformed by the jaw of the adhesive layer, resulting in poor printing. There was a problem that caused.

Moreover, the said adhesive sheet has a laminated structure which consists of an adhesive layer formed in the base material and the surface of the at least one side of a base material, and at least 2 types of manufacture of a base material and manufacture of an adhesive layer (adhesive processing process with respect to a base material) from a manufacturing surface Because of the necessity of the manufacturing process, a large amount of organic solvent must be used while the cost is high, and thus there is a problem that it is not preferable in terms of production efficiency, cost reduction, and environmental problems.

In addition, in the said adhesive sheet, when winding in roll shape, in order to protect an adhesive layer, in order to protect an adhesive layer, a peeling liner should be provided on an adhesive layer, The manufacturing process number and material cost of that much increase, and production efficiency is bad and expensive, but peeling off There existed unreasonable reasons such that the release agent derived from the liner migrated to the pressure-sensitive adhesive layer to degrade the performance of the pressure-sensitive adhesive.

Accordingly, the present inventors have studied to solve the above problems and found that the above problems can be solved by using a cleaning sheet having a single layer structure having a specific property value (Patent Document 3).

However, when the cleaning sheet is rolled alone and used in a rolled state, blocking occurs between the rolled sheets, and a force for drawing the sheet from the roll is required.

The present invention is a single-layered cleaning sheet that is well suited for cleaning screen printing plates and is advantageous in terms of production efficiency, cost, and environment, while preventing blocking when the cleaning sheet is wound in a roll shape alone while maintaining excellent cleaning performance. It is an object of the present invention to provide a cleaning sheet which effectively prevents and improves the feeding of the sheet from the roll so as to be smoothly carried out, and further improves the ease of handling and operability when used in a roll shape.

Moreover, an object of this invention is to provide the cleaning method of the screen printing plate using the said cleaning sheet.

The present invention relates to the following matters, for example.

The cleaning sheet according to the present invention is a cleaning sheet obtained by irradiating an electron beam of 1 to 50 Mrad to at least one side of a single layer sheet containing a resin, and has the following physical properties (i) and (ii); (i) the solvent absorption after immersion in diethylene glycol monobutyl ether acetate for 1 second is 5 g / m 2 or more, and (ii) the storage modulus measured at 23 ° C. and 11 Hz is in the range of 5.00 × 10 ^{6 to} 3.00 × 10 ⁸ Pa. to be.

The cleaning sheet preferably has a tensile shear bond strength (based on JIS K 6850) of 0.01 to 1.0 N / mm 2 measured after pressing one surface thereof onto a stainless plate.

In addition, the cleaning sheet preferably has a peeling force of 90 ° (based on JIS Z 0237) of 2.ON / 25 mm or less.

It is preferable that the said cleaning sheet exists in the range of 30-100000 micrometers in thickness.

Moreover, it is preferable that the said cleaning sheet is a roll shape wound alone.

In addition, the cleaning sheet can be suitably used for cleaning screen printing plates.

In addition, in the cleaning method of the screen printing plate according to the present invention, by adhering the back surface of the cleaning sheet and the screen printing plate, the ink paste residue adhered to the back surface is transferred to the cleaning sheet,

The cleaning sheet is then peeled off the back surface of the screen printing plate together with the ink paste dregs.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated concretely.

<Cleaning sheet>

The cleaning sheet according to the present invention is a cleaning sheet obtained by irradiating at least one surface of a single layer sheet containing a resin with an electron beam of 1 to 50 Mrad, and has the following physical properties (i) and (ii).

That is, the cleaning sheet (i) solvent absorption after immersion in diethylene glycol monobutyl ether acetate for 1 second is 5g / ㎡ or more, and (ii) the storage modulus measured at 23 ℃, 11Hz is 5.00 × 10 ⁶ ~ 3.0 × In the range of 10 to ⁸ Pa.

That is, the cleaning sheet of the present invention is a sheet having a single layer structure having a specific physical property value obtained by irradiating an electron beam of 1 to 50 Mrad to at least one surface of a single layer sheet containing a resin, and the substrate and at least one side of the substrate. The structure clearly differs from the conventionally well-known adhesive sheet for screen printing plate cleaning which has a laminated structure which consists of an adhesive layer formed in the inside.

First, the physical properties (i) and (ii) will be described.

The cleaning sheet of the present invention is very useful for removing solvent content such as ink paste debris smearing on a screen printing plate, in particular, paste form in which at least a part of solvent is volatilized or semi-solidified ink paste debris from ink paste smearing on a screen printing plate. It has a suitable solvent absorption performance.

In general, various solvents are known as solvents for ink pastes used for screen printing in PDP or LCD manufacturing. Examples of the solvent used for the phosphor ink paste of PDP include, for example, diethylene glycol mono methyl ether acetate, diethylene glycol mono ethyl ether acetate, diethylene glycol mono butyl ether acetate, dipropylene glycol mono methyl ether acetate, di Dialkylene glycol monoalkyl ether acetates such as propylene glycol monoethyl ether acetate, dipropylene glycol monobutyl ether acetate; diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, dipropylene glycol mono And dialkylene glycol monoalkyl ethers such as methyl ether, dipropylene glycol monoethyl ether and dipropylene glycol monopropyl ether.

Therefore, the cleaning sheet of the present invention preferably has a suitable solvent absorption performance for this solvent, but for the sake of convenience, in the present specification, the amount of solvent absorption is defined in relation to diethylene glycol monobutyl ether acetate.

That is, the solvent absorption amount in this specification means the solvent absorption amount after immersing a cleaning sheet in diethylene glycol mono butyl ether acetate for 1 second in 23 degreeC under air | atmosphere, It is preferable that the said solvent absorption amount is 5 g / m <2> or more, It is 6 g It is more preferable that it is / m <2> or more. In addition, an upper limit is although it does not specifically limit, Usually, it is 50 g / m <2> or less.

When the solvent absorption amount is more than the lower limit, the cleaning sheet can sufficiently absorb the solvent contained in the solvent-containing matter such as ink paste residues, and thus, the adhesion of solvent-containing substances such as ink paste residues to the cleaning sheet is facilitated.

In addition to the solvent absorbing amount described above, the storage elastic modulus measured at 23 ° C. and 11 Hz is typically 5.00 × 10 ^{6 to} 3.00 × 10 ⁸ Pa, preferably 8.00 × 10 ^{6 to} 1.00 × 10 ⁸ Pa, More preferably, it is the range of 1.00 * 10 <^7> -8.00 * 10 <^7> Pa.

When the storage elastic modulus measured at 23 ° C. and 11 Hz is within the above range, the cohesive force of the cleaning sheet is moderately high, and the cleaning sheet stretches and tears when peeling after peeling the cleaning sheet and the object to be cleaned, for example, the back surface of the screen printing plate. It has sufficient strength to prevent it from falling, and no deposits such as sheet material (a part of the cleaning sheet) remain on the screen printing plate after cleaning sheet peeling. If the storage elastic modulus is within the above range, the balance of the flexibility of the cleaning sheet and the shape-protective retention performance is good, so that the cleaning sheet can be easily handled, for example, a screen printing plate, and the cleaning sheet can be handled alone. .

Moreover, it is preferable that the cleaning sheet of this invention has other physical property in addition to the physical property of said (i) (ii).

Specifically, the cleaning sheet of the present invention generally has a tensile shear bond strength (based on JIS K 6850) measured after pressing one surface of the cleaning sheet onto a stainless steel plate, preferably 0.01 to 1.0 N / mm 2, preferably It is preferable to exist in the range of 0.03-0.5 N / mm <2>.

In addition, the tensile shear bond strength in the present specification means a value measured according to JIS K 6850. In the case where the measurement object has a single layer structure, in order to eliminate the influence due to the elongation of the measurement object itself, the stainless steel plate of the measurement object The value measured by JISK6850 using the thing which bonded the adhesive film (The adhesive layer was provided in one side of 25-micrometer-thick polyethylene terephthalate (PET) film) on the opposite side to the surface crimped | bonded as a measurement sample. Means.

If the tensile shear bond strength of the cleaning sheet is within the above range, it is preferable because the cleaning sheet exhibits excellent cleaning performance. For example, when the object to be cleaned is a screen printing plate, adhesiveness sufficient for removing the ink paste residue adhering to the back surface of the screen printing plate can be exhibited, and the screen printing plate is not stretched and deformed. An adhesive property here means having a cleaning object different from what is called rapid adhesiveness (tack) of an adhesive, for example, following the back surface of a screen printing plate, and having a protective holding force with respect to the force of the shear direction.

In addition, the tensile shear bond strength value is preferably achieved on at least one side of the cleaning sheet of the present invention, that is, on one or both sides of the cleaning sheet, but in practice, the surface used for cleaning, for example, of a screen printing plate. In the case of cleaning, it may be achieved on the surface used for cleaning by pressing the back surface of the screen printing plate. If the property value is achieved only on the surface, even if the tensile shear bond strength of the other side does not reach the property value, it is not suitable for use. The latter state is more preferable in the sense of blocking prevention or the like, from the standpoint of rolling alone and forming a roll shape.

In addition, it is preferable that the type A durometer hardness (based on JIS K 6253) of the cleaning sheet of this invention is 70-96 normally, Preferably it is 75-93, More preferably, it is the range of 80-10.

When the type A durometer hardness is in the above range, a part of the cleaning sheet (sheet material) does not remain attached to the object to be cleaned, for example, the screen printing plate, due to the decrease in the cohesive force of the cleaning sheet, and also excellent in the followability to the screen printing plate.

Such a cleaning sheet can be obtained by irradiating 1-50 Mrad of electron beams to at least one surface of the single-layer sheet containing resin.

Although it does not specifically limit as said resin, For example, polyurethane-type resin, (meth) acrylic resin, the ethylene vinyl acetate copolymer, the ionomer of an ethylene (meth) acrylic acid copolymer, a polyamide resin, a polystyrene resin, a polyolefin resin, Polycarbonate resin, phenoxy resin, polyvinyl hydrochloride resin, polyvinyl acetate resin, polo acetal resin, polybutylene terephthalate resin, acrylonitrile butadiene copolymer, acrylonitrile styrene copolymer, styrene butadiene styrene Block copolymers, styrene isoprene styrene block copolymers, ABS resins and the like. These may be used individually by 1 type, and may be used as a resin composition or a copolymer in combination of 2 or more type.

Among them, polyurethane-based resins, polyvinyl chloride resins, and polyvinyl acetate resins are preferred, and polyurethane-based resins are more preferred in terms of excellent followability to the object to be cleaned when molded on a sheet.

As polyurethane-type resin, a polyurethane elastomer is mentioned, Especially, a thermoplastic polyurethane elastomer is mentioned preferably.

Thermoplastic polyurethane elastomers (hereinafter simply referred to as TPUs) are generally obtained by reacting long chain polyols, chain extenders, diisocyanates, and soft segments and chain extenders having structural units derived from long chain polyols. It consists of a hard segment having a polyurethane structure obtained by reaction with a diisocyanate.

If TPU is classified according to the kind of long-chain polyol used as this soft segment component, it can be classified into a polyester type polyurethane elastomer, a polyether polyurethane elastomer, a polycarbonate polyurethane elastomer, etc. In the present invention, polyether-based polyurethane elastomers are preferably used among these.

Specific examples of the long chain polyol include polyester polyols such as lactone polyester polyols and adipate polyester polyols; Polyether polyols such as polypropylene (ethylene) polyol and poly tetramethylene ether glycol; And polycaponate polyols. In the present invention, polyether polyols are preferably used among these, and the number average molecular weight is usually 6OO to 50OO.

Examples of the diisocyanate include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenyl methane diisocyanate (pure MD I), hexamethylene diisocyanate and the like. In these, pure MD I is used preferably.

Examples of the chain extender include low molecular polyhydric alcohols such as 1,4-butanediol, 1, and 6-hexanediol, aromatic diamines, and the like.

By adjusting the compounding amount of such a long chain polyol, diisocyanate and chain extender and adjusting the soft segment amount and the hard segment amount, a TPU having a desired physical property value can be produced. As a general tendency at this time, when the amount of hard segments constituting the TPU increases, the storage modulus and hardness increase, but the tensile shear bond strength decreases, and when the amount of soft segments increases, the opposite tendency appears.

Moreover, you may mix | blend various additives, a solvent, etc. with the said resin in the quantity within the range which does not impair the effect of this invention as needed.

As an additive, For example, fillers, such as an organic powder or an inorganic powder; Plasticizers, such as an aromatic ester and chlorinated paraffin; UV absorbers; Antioxidants; coloring agent; Antistatic agents and the like. These can be used individually by 1 type or in combination of 2 or more type.

As a solvent, what is necessary is just to be able to fully melt | dissolve or disperse the above-mentioned resin and additive in a well-known solvent, and it does not specifically limit.

According to well-known molding methods, such as extrusion molding, compression molding, inflation molding, calender molding, cast method, etc., the resin composition obtained by mixing, heating, dissolving, melting, etc. suitably above-mentioned resin or said each component by a well-known method suitably is carried out. Molded into a single layer sheet. Then, the cleaning sheet of the present invention can be obtained by irradiating at least one surface of the obtained monolayer sheet with an electron beam of 1 to 50 Mrad.

Further, the solution obtained by dissolving the resin or resin composition in a suitable solvent is applied and dried on a substrate with a dip coat or spin coat to form a film, and then the substrate is peeled off to obtain a single layer sheet. You may obtain the cleaning sheet of this invention by irradiating an electron beam of 1-50 Mrad to a surface.

The electron beam irradiation treatment is performed by irradiating a transfer line of 1 to 50 Mrad on one or both surfaces of the single layer sheet under conditions of an acceleration voltage of 130 to 300 Kv and a beam current of 10 to 30 mA, usually under a nitrogen stream.

Preferably, the electron beam of 3-40 Mrad was irradiated under the conditions of the acceleration voltage of 150-250 kV of hot electrons, and the beam current of 15-25 mA under nitrogen stream.

In addition, when irradiating an electron beam exceeding 20Mrad to a single | mono layer sheet, you may irradiate an electron beam exceeding 20Mrad once, and you may irradiate an electron beam of 20Mrad or less several times until the total irradiation dose becomes a predetermined amount.

Under these conditions, when the electron beam irradiation treatment is provided with a single layer sheet, the surface layer of the irradiated surface is crosslinked, and the blocking is satisfied while satisfying the predetermined values for tensile shear adhesive strength, storage modulus, type A durometer hardness, solvent absorption amount, and the like. Feeding of the sheet at the time of effectively preventing and winding independently in roll shape can be improved, and the cleaning sheet which further improved the ease of handling and operability in roll form can be obtained. In addition, although the said electron irradiation process may be performed on both surfaces of a single | mono layer sheet, from a viewpoint of blocking prevention, it is sufficient if it is usually given only to one surface, especially the surface opposite to the surface used for cleaning.

Using the cleaning sheet obtained in this way, the screen printing plate can be cleaned very suitably. A sheet used for cleaning a conventional screen printing plate recovers a sheet already used for cleaning a printing plate, and is used while feeding the sheet while the sheet is wound in a roll shape to newly use an unused sheet for cleaning. Is efficient.

However, in the case of using a conventionally known so-called pressure-sensitive adhesive sheet as such a sheet, it is necessary to provide a release liner on the pressure-sensitive adhesive layer in order to protect the pressure-sensitive adhesive layer from adhesion between the pressure-sensitive adhesive layer and the base material superimposed thereon when winding in a roll shape. .

Moreover, since the cleaning sheet which consists of a single | mono layer sheet described in patent document 3 has high shape protection holding performance, it can be wound by roll shape independently, without providing a peeling liner, but blocking occurs between the wound sheets when used in roll state. As a result, the feeding of the sheet from the roll is not performed smoothly, and the feeding force is required.

On the other hand, in the cleaning sheet of this invention, blocking of sheets is effectively prevented, the feeding | feeding out of the sheet when winding alone in roll shape improves, and the ease of handling in a roll shape, and operability are improved more.

The ease of feeding out the cleaning sheet from the roll when the cleaning sheet is wound in a roll shape alone can be evaluated by measuring the 90 ° peeling force (based on JIS Z0237) of the cleaning sheet.

The 90 degree peeling force of a cleaning sheet can be calculated | required by measuring the 90 degree peeling force of the back surface of a sheet with respect to the said sheet surface based on the 90 degree peeling method of JISZ0237. Specifically, as shown in FIG. 1, after left for 24 hours in a state where the surfaces and the back surfaces of the two cleaning sheets overlapped, one side of the cleaning sheet (fixed side test pieces 3) is fixed to the substrate 1. The force required for peeling off the cleaning sheet (movable side test piece 5) which is not fixed to the other side substrate 1 and peeling it so that the angle formed by both sheets becomes 90 degrees. (N / 25mm) It is measured as

The 90 ° peeling force (based on JIS Z0237) of the cleaning sheet of the present invention is preferably 2.ON / 25 mm or less, and more preferably in the range of 0.01 to 1.5 N / 25 mm. If the 90 degree peeling force (based on JIS Z0237) of a cleaning sheet is below the said value, a sheet can be taken out smoothly from the cleaning sheet wound by roll shape, and the ease of handling and operability in a roll shape improve.

In addition, the thickness of the cleaning sheet can be wound in a roll shape, and at the same time, it is usually 30 to 100Om, preferably in terms of having an appropriate breaking strength that can withstand the peeling operation of the cleaning object, for example, a screen printing plate. Preferably it is the range of 50-60000 micrometers. The width of the cleaning sheet can be appropriately selected according to the size of the cleaning object, for example, a screen printing plate.

<Cleaning method of screen printing board>

In the cleaning method of the screen printing plate of the present invention, by adhering the back surface of the cleaning sheet and the screen printing plate, the ink paste residue adhered to the back surface is transferred to the cleaning sheet,

The cleaning sheet is then peeled off the back surface of the screen printing plate together with the ink paste dregs.

More specifically, for example, by pressing a roll-shaped cleaning sheet wound alone, it is pressed against the back surface of the screen printing plate, and the ink paste residue adhered to the back surface is transferred to the cleaning sheet and peeled off for each cleaning sheet. This removes ink paste debris from the back surface.

Moreover, in the shaping | molding method of a sheet | seat or a process, the tensile shear adhesive strength in the front and back of the obtained cleaning sheet may differ. In this case, the above-described tensile shear bond strength (based on JIS K 6850) is preferably used so as to be in contact with the surface in the range of 0.01 to 1.0 N / mm 2 and the back surface of the screen printing plate.

At this time, (i) the roll for fixing the screen printing plate and press-fitting the cleaning sheet may be moved while pressing the back side of the printing plate through the cleaning sheet to feed the cleaning sheet, or (ii) the roll may be fixed and the cleaning sheet may be reversed. The screen printing plate may be moved to move the screen printing plate while pressing the back surface of the screen printing plate and the cleaning sheet on the roll, and (iii) both the rolls for pressing the cleaning sheet and the screen printing plate may be pressed while moving through the cleaning sheet. You may feed out a cleaning sheet by doing so.

The cleaning sheet and the cleaning method of the present invention are very suitable for removing the solvent-containing deposits (solvent-containing substances such as paste or semi-solidified ink paste residues) from the object to be cleaned, and in particular, precision electronic parts and optical parts It is preferably applied to the cleaning of screen printing plates used in manufacturing processes such as the like. The precision electronic component and the optical component may be any one having a screen printing process in the manufacturing process, and are not particularly limited. For example, the precision electronic component and the optical component can be preferably used for screen printing plates used in PDPs.

Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to this Example.

In Examples and Comparative Examples, (1) measurement of tensile shear bond strength, (2) measurement of storage modulus, (3) measurement of type A durometer hardness, (4) measurement of solvent absorption, and (5) cleaning property Test, (6) The measurement of the 90 ° peel force is carried out by the following method.

(1) Measurement of tensile shear bond strength

According to JIS K 6850, the test piece obtained by cutting the measurement object to 25 mm x 100 mm is pressed onto the end surface of SUS 430BA with a 2 kg rubber roll so that the pressing area is 25 mm x 12.5 mm, and sheared at a tensile speed of 50 mm / min. It pulled in the (iii) direction, the maximum load until peeling was measured, and the tensile shear bond strength was computed from the said maximum load.

However, in the case where the measurement object is a single-layered structure sheet, in order to eliminate the influence of the elongation of the measurement object at the time of measurement, on one side of the PET film having a thickness of 25 μm on the opposite side to the surface that is pressed onto the SUS 430BA of the measurement object. Peeled and peeled the peeling sheet from the adhesive film (brand name "PET25 (A) PL new 8LK"; Lintec Co., Ltd. product) provided with the adhesive layer of 20 micrometers in thickness, and cut into 25 mm x 100 mm Was used as a test piece.

(2) measurement of storage modulus

The storage elastic modulus was measured using the viscoelasticity measuring apparatus (brand name "Leopifron DDV-II-EA"; product made from Orient Tech Co., Ltd.) on the conditions of 23 degreeC and 11 Hz.

(3) Measurement of type A durometer hardness

Type A durometer hardness was measured according to JIS K61253.5.4.

(4) Measurement of solvent absorber

Solvent absorption amount after measuring the weight of the cleaning sheet, using diethylene glycol mono butyl ether acetate as a solvent and immersing the cleaning sheet in the solvent for 1 second at 23 ℃ under an air atmosphere, and then filter paper (brand name "kim wipe wiper (S200); manufactured by Clecia Co., Ltd.), the solvent adhering to the surface was removed, and the weight after immersion was measured to calculate the weight difference before and after immersion.

(5) cleaning test

On the back side of the screen printing plate (stainless steel plate manufactured by Tokyo Process Service Co., Ltd.) where the ink paste is smeared, the cleaning sheet obtained in the examples and the comparative examples is pressed by using a 2 kg rubber roll, and then peeled and ink is printed on the printing plate. It was visually checked whether the paste remained, the presence or absence of the residue of the sheet | seat material on the board, the cleaning sheet after use, and the presence or absence of wrinkles. In addition, about the cleaning sheet | seat in which the electron beam irradiation process was given to one side, it was used for cleaning, so that the surface opposite to the electron beam irradiation process surface may contact the printing plate.

(6) Measurement of 90 ° peeling force

Based on the 90 degree peeling method of JISZ0237, two test pieces obtained by cutting a measurement object to 25 mm x 250 mm were left to stand for 24 hours in the state which overlapped the surface and back surface of a test piece as shown in FIG. Then, while fixing the test piece (fixed side test piece 3) of one side to the substrate 1, while peeling the test piece (movable side test piece 5) that is not fixed to the other substrate 1 The force (N / 25mm) required for peeling was measured so that the angle formed by both test pieces by lifting might be 90 degrees.

Example 1

Polyether-based polyurethane elastomer (trade name "Rezamin P-2283"; product of Daiichi Seika Industries Co., Ltd.) is heated to 200 ° C and melted, and a process film (trade name "PET50 AL-" 5 &quot;; melt extrusion was carried out in a sheet shape having a thickness of 80 [micro] m on a Lintec Co., Ltd. product, and the cooling drum was pressed and cooled on one side (surface opposite to the process film) of the sheet obtained, It wound in roll shape with a process film. Subsequently, the process film was peeled from the roll while repeating the sheet, and on one side (the side on which the cooling drum was pressed) under an air stream using an electron beam irradiation apparatus, an acceleration voltage of 200 kV, a beam current of 20 mA, a dose of 5 Mrad, and a target to be irradiated. The electron beam was irradiated (total irradiation dose 5 Mrad) on the condition of 20 mm of distance, it was wound up in roll shape again, and the roll-shaped cleaning sheet was obtained.

Using the obtained cleaning sheet, the tensile shear bond strength, the storage elastic modulus, the type A durometer hardness, the measurement of a solvent absorption amount, the cleaning test, and the 90 degree peeling force were measured.

The results are shown in Table 1.

Example 2

A rolled cleaning sheet was obtained in the same manner as in Example 1 except that the dose of the electron beam was changed to 40 Mrad (20 Mrad was irradiated twice, and the total irradiation dose was 40 Mrad).

Using the obtained cleaning sheet, the measurement of tensile shear bond strength, storage elastic modulus, type A durometer hardness, solvent absorption amount, the cleaning test, and the 90 degree peeling force were performed.

The results are shown in Table 1.

Comparative Example 1

A roll-like cleaning sheet was obtained in the same manner as in Example 1 except that the dose of the electron beam was changed to 60 Mrad (30 Mrad was irradiated twice and the total irradiation dose was 60 Mrad).

Using the obtained cleaning sheet, the measurement of tensile shear bond strength, storage elastic modulus, type A durometer hardness, solvent absorption amount, the cleaning test, and the 90 degree peeling force were performed.

The results are shown in Table 1.

Comparative Example 2

A roll-like cleaning sheet was obtained in the same manner as in Example 1 except that the electron beam irradiation treatment was performed.

Using the obtained cleaning sheet, the tensile shear bond strength, the storage elastic modulus, the type A durometer hardness, the measurement of the solvent absorption amount, the cleaning test, and the 90 ° peeling force were measured.

The results are shown in Table 1.

Electron Beam Dose (Mrad) Tensile Shear Adhesion Strength (N / ㎡) Storage modulus E ³ (Pa) Type A Durometer Hardness Solvent Absorption (g / ㎡) Cleanability test 90 ° Peeling Force (N / 25mm) Paste Remaining on Printing Plate Attachment to the Printing Plate Ruptures and Wrinkles of Sheets Example 1 5.0 0.070 2.37 × 10 ⁷ 84 6.89 radish radish radish 0.9 Example 2 40.0 0.030 7.29 × 10 ⁷ 85 6.13 radish radish radish 0.2. Comparative Example 1 60.0 Not measurable ^{* 1} 3.10 × 10 ⁸ 98 4.33 U radish U Not measurable ^{* 2} Comparative Example 2 0.0 0.130 1.39 × 10 ⁷ 83 8.77 radish radish radish 11.0

* 1: Can not measure because it is not adhered to SUS 430BA

* 2: The cleaning sheet is fragile and broken, not measurable

In Table 1, Examples 1 and 2, which were subjected to irradiation treatment of a specific amount of electron beams, had a similar cleaning performance as compared with Comparative Example 2 which did not perform such a treatment, and blocking of sheets was prevented from being rolled. It can be seen that feeding of the sheet is improved. Further, in Comparative Example 1 in which the scanning amount of the electron beam deviated from the specific amount, it was found that the cleaning performance was inferior and the feeding of the sheet from the roll was impossible.

According to the cleaning sheet of the present invention, the object can be reliably cleaned without damaging or contaminating the object to be cleaned. For example, in the case where the object to be cleaned is a screen printing plate, it is possible to prevent print defects caused by damage to the screen printing plate, adhesion of tickles, dust, or sheet material, and to remove ink paste residues reliably removed from the back surface of the screen printing plate. Can be. In other words, since the cleaning sheet of the present invention has a single layer structure, unlike an ordinary adhesive sheet having an adhesive layer on a substrate, even if the cleaning operation on the back of the screen printing plate is repeated, the adhesive is peeled off and adhered to the back of the screen printing plate to prevent print defects. It does not generate, is easy to handle and can simplify the manufacturing process, which is advantageous in terms of production efficiency, cost and environment.

Further, according to the cleaning sheet of the present invention, the blocking of the sheets when rolled alone into the roll shape can be effectively prevented, and the feeding of the sheet from the roll can be smoothed, thereby further improving the ease of handling and operability in the roll shape. You can.

In addition, according to the cleaning method of the screen printing plate of the present invention, it is possible to prevent the occurrence of printing defects caused by damage to the screen printing plate, adhesion of dust or dust or sheet material to the screen printing plate, and to prevent ink paste residues spread on the back surface of the screen printing plate. It can be removed reliably.

Claims (7)

A cleaning sheet obtained by irradiating an electron beam of 1 to 50 Mrad to at least one surface of a single layer sheet containing a resin, the cleaning sheet having the following physical properties (i) and (ii); (i) the solvent absorption after immersion in diethylene glycol monobutyl ether acetate for 1 second is at least 5 g / m 2, (ii) The storage modulus measured at 23 ° C. and 11 Hz is in the range of 5.0 × 10 ^{6 to} 3.00 × 10 ⁸ Pa. The method of claim 1, And a tensile shear bond strength (based on JIS K 6850) measured after pressing one surface of the cleaning sheet onto a stainless plate, in a range of 0.01 to 1.0 N / mm 2. The method of claim 1, A cleaning sheet characterized by a 90 ° peeling force (based on JIS Z O237) of 2.0 N / 25 mm or less. The method of claim 1, The cleaning sheet has a thickness in the range of 30 to 1000 µm. The method of claim 1, The cleaning sheet characterized by the roll shape wound alone. The method of claim 1, A cleaning sheet used for cleaning a screen printing plate. By contacting the cleaning sheet according to any one of claims 1 to 6 with the back surface of the screen printing plate, the ink paste residue adhered to the back surface is transferred to the cleaning sheet, And then the cleaning sheet is peeled off from the back surface of the screen printing plate together with the ink paste dregs.

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