JP2008080645A - Cleaning method using cleaning sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce unevenness when a removal objective article which has adhered to the surface is removed by using a cleaning sheet when a body to be cleaned is a flexible sheet-form article. <P>SOLUTION: The removal objective article 201 which has adhered to a first surface S1 of the body S to be cleaned which is the flexible sheet-form article is removed by pressing this cleaning sheet 1 to the first surface S1. In this case, by pressing the first member P1 from the back of the sheet 1, the sheet 1 is locally pressed to the first surface S1, and at the same time, a second member P2 is pressed to a region corresponding to the pressed region with a relationship of the front and the rear in the second surface S2 of the body S to be cleaned. While making the two regions compete each other, the pressed section of the sheet 1 is moved to the body S to be cleaned, and the removal objective article 201 is transferred to the sheet 1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cleaning method using a cleaning sheet for cleaning (removing from a cleaned object) an object to be removed such as paste or ink attached to the cleaned object, and in particular, a plasma display panel The present invention relates to a method for wiping off a phosphor paste that is behind the objective surface of a screen printing plate in the production of a phosphor layer incorporated in (PDP).

In recent years, PDPs (particularly color PDPs) have larger screens and higher definition, and the arrangement pattern of RGB phosphors in the phosphor layer has become finer and higher density.
In the step of forming the phosphor layer, as shown in a schematic cross-sectional view in FIG. 9A, the phosphors of the RGB three primary colors are arranged on the substrate 100 so as to draw a high-definition stripe. The arrangement pattern is a pattern in which stripes having three sets of (R, G, B) as one set are repeated. A partition 110 exists between the bands of the phosphors. That is, the phosphors are respectively disposed in grooves formed in stripes on the plate surface of the substrate 100.

As a method for disposing each phosphor on the substrate in a high-definition pattern as described above, screen printing is used as shown in FIG.
FIG. 9B is an enlarged view of one groove of the phosphor layer shown in FIG. 9A, and the screen printing plate S is overlaid on the substrate 100 and is opened from the opening (through hole) S20. A state in which the phosphor paste 200 is fed into the groove is shown.
The thick wavy lines drawn inside the screen printing plate suggest a so-called “screen” woven with a wire made of a polymer material or a metal material. As shown in FIG. 10, when the plate surface of the screen printing plate is viewed, the screen S10 is exposed in the opening, and the phosphor paste is printed on the surface of the object through the mesh.

  When the phosphors are printed in stripes, it is ideal to suppress the penetration of the adjacent phosphor paste and to arrange the phosphor pastes of the respective colors in the grooves in a pure state. If adjacent phosphors are mixed even locally, it is impossible to display an accurate screen only at that portion. Therefore, particularly in products sold as high-grade products, strict quality is required for the arrangement of the phosphors.

As a problem of the printing technique itself when screen-printing the phosphor, after a certain number of times of printing, as shown in FIG. 9B, the surface S1 on the object side of the screen printing plate S (especially the opening S20). There is a problem that the phosphor paste 201 remains and accumulates around the substrate).
Such residue and deposition of the phosphor paste on the surface of the object of the screen printing plate is called “the back of the phosphor paste”, and the residue is transferred to the upper part of the partition wall of the object substrate. As a result, accurate and beautiful phosphor arrangement is impossible.

In order to prevent the above-described quality troubles due to the backside, a method of removing the backside phosphor paste (backside paste) using a cleaning sheet is known (for example, Patent Documents 1 to 7). .
For example, Patent Documents 1, 2, 4 to 7 disclose a method in which an adhesive sheet is used as a cleaning sheet and the phosphor paste is removed by its adhesive force. Patent Document 3 describes a composite member in which a porous layer (porous layer) such as a net is laminated on an adhesive layer.
On the other hand, a screen printing apparatus in the current manufacturing process of a PDP incorporates a cleaning apparatus configured to remove the back paste with a cleaning sheet (mainly an adhesive sheet).

  FIG. 11 is a diagram showing an example of such a cleaning apparatus, and the adhesive sheet A10 is attached to and peeled off from the plate surface of the screen printing plate S (the surface on the side in contact with the substrate of the PDP) S1 between screen printings. Thus, the backside paste is removed. More specifically, the back surface paste 201 is deposited on the plate surface S1, and the adhesive sheet A10 is pressed against the plate surface S1 by the roller P10 behind the plate surface S1. The roller P10 moves in parallel to the right side of the figure as indicated by the thick arrow in the figure while pressing the adhesive sheet A10 against the plate surface of the screen printing plate. By this operation, the back paste is sequentially peeled off from the adhesive surface of the adhesive sheet A10. Also, as indicated by a thin arrow, a new pressure-sensitive adhesive sheet A10 is fed from a lower right unwinding device (not shown), and a dirty pressure sensitive adhesive sheet A10 is taken up by a lower left winding device (not shown). It is the structure which can be cleaned with a new adhesive sheet.

However, with regard to the cleaning device as described above, the present inventors have examined the removal performance of the backside paste in detail, and in the method of pressing the cleaning sheet against the screen printing plate by a roller, the backside paste is removed. It was found that an insufficient portion was locally generated and the removal property was uneven.
Also, as a result of investigating the cause, the screen printing plate is a flexible thin sheet material, so that the screen printing plate bends due to the pressing force of the roller, and the cleaning sheet does not contact the plate surface evenly. It turned out to be the cause.
Such a problem with the unevenness of removability is a problem that occurs not only in the case of screen printing plates but also if the object to be cleaned is a thin and flexible sheet-like material.
JP 2000-177110 A JP 2001-348541 A JP-A-11-224414 Japanese Patent No. 3280367 Japanese Patent Laid-Open No. 10-180991 Japanese Patent Laid-Open No. 10-250043 JP-A-6-297681

  The problem to be solved by the present invention is that, when the object to be cleaned is a flexible sheet-like object, it is possible to reduce unevenness when the object to be removed attached to the surface is removed using the cleaning sheet. It is in.

As a result of earnest research to solve the above problems, the present inventors firstly deformed the object to be cleaned because it is flexible, so that a portion where the cleaning sheet acts strongly and a portion where the cleaning sheet does not act are generated. I found out. Furthermore, in order to eliminate the above-mentioned deformation, the present inventors have arranged a support member to counter the pressing of the cleaning sheet on the back surface of the object to be cleaned, and pushed back from the back side. The present invention has been completed by neutralizing the deformation of the substrate, making the contact of the cleaning sheet with the surface of the object to be cleaned uniform, and eliminating the unevenness of removability.
That is, the present invention has the following characteristics.

(1) A method of removing an object to be removed attached to a first surface of an object to be cleaned which is a flexible sheet-like material by pressing the cleaning sheet against the surface,
By pressing the first member from behind the cleaning sheet, the cleaning sheet is locally pressed against the first surface of the cleaning object, and the object to be cleaned is pressed against the pressed area. While the second member is pressed against the corresponding area on the second surface of the second surface, the pressing portion of the cleaning sheet is moved relative to the object to be cleaned, and the object to be removed is transferred to the cleaning sheet. A cleaning method, characterized by taking.
(2) The cleaning method according to (1), wherein the first member is a roller.
(3) The cleaning method according to (1) or (2), wherein the second member is a squeegee.
(4) The cleaning method according to (1) or (2), wherein the second member is a roller.
(5) The cleaning sheet is formed so as to remove the object to be removed by rubbing against the object to be cleaned, and at least one surface of the cleaning sheet should be rubbed against the object to be cleaned. The cleaning method according to any one of (1) to (4), wherein the object surface is an uneven surface.
(6) The cleaning method according to any one of (1) to (5), wherein the object to be cleaned is a screen printing plate for forming a phosphor layer of a plasma display panel.

FIG. 12 is a diagram for explaining the non-uniformity of removability and the cause when the cleaning sheet is simply pressed from one side as in the prior art. As shown in FIG. 12A, when the trace of the pressure-sensitive adhesive sheet A10 being pressed against the screen printing plate S by the roller P10 is observed in detail, a belt-like region m at the center of the trace that the roller P10 has passed through the pressure-sensitive adhesive sheet. As shown by hatching, the back paste is not sufficiently removed as compared to the regions on both sides of the passing trace, and the removal state is uneven.
The cause is that the screen printing plate is bent along the pressed roller because the screen printing plate S is a thin and relatively stretchable sheet-like material as shown in FIG. Due to this deflection, the pressure-sensitive adhesive sheet is pressed sufficiently strongly against the plate surface at both end portions of the roller to exhibit preferable removability, but the force that strongly presses the pressure-sensitive adhesive sheet against the plate surface does not act at the central portion of the roller, and preferable removability is obtained. Not shown.
On the other hand, in the present invention, as shown in FIG. 1, the first member (roller in the figure) P1 is pressed from behind the cleaning sheet 1, and at the same time, the second region is placed in the area directly behind the pressed area. The member P2 is pressed against the force from the first member P1.
Thus, by making the 2nd member P2 oppose on the back surface of the to-be-cleaned body S, a deformation | transformation of a to-be-cleaned body is suppressed effectively, and the uniform removability over the 1st member P1 whole is obtained. become.

FIG. 1 is a diagram for explaining the cleaning method of the present invention, and shows an example of a cleaning device configured to be able to carry out the cleaning method.
The object to be cleaned S is a flexible sheet-like object (screen printing plate in the figure), and an object to be removed (back paste in the figure) 201 is attached to the first surface S1. In the cleaning method, the cleaning sheet 1 is locally pressed against the first surface S1 of the body S to be cleaned by the first member P1 disposed behind the sheet, and at the same time against the pressed area. The second member P2 is pressed against the region corresponding to the front / back relationship on the second surface (back surface) S2 of the object to be cleaned S to balance with the first member P1 to suppress deformation of the object to be cleaned. While being in such a state, as indicated by a thick arrow, the portion to which the cleaning sheet 1 is pressed is moved relative to the object to be cleaned S, and the removal target 201 is transferred to the cleaning sheet 1. It is what. The object to be removed transferred onto the cleaning sheet is indicated by reference numeral 202.
Due to this feature, as described in the explanation of the above action, the unevenness of removability is suppressed.

The to-be-cleaned body should just be a flexible sheet-like object. Also, the removal object attached to the surface is not particularly limited, but semi-solid materials containing a solvent and in a wet state, for example, various pastes, inks, glues, adhesives, paints, etc. are mainly removal objects. As mentioned. The object to be removed may be one that does not contain a solvent, or may be a material that is a semi-solid substance in a damp state.
Among the combinations of the object to be cleaned and the object to be removed, as described in the description of the background art, screen printing for forming the phosphor layer of the PDP has problems associated with higher definition. Therefore, when the object to be cleaned is a screen printing plate for forming a phosphor layer of PDP and the object to be removed is a phosphor paste for forming the phosphor layer, the utility of the cleaning method is useful. Becomes particularly prominent.

When the object to be removed contains a solvent, examples of the solvent include aliphatic hydrocarbons such as hexane, heptane, and mineral spirits; alicyclic hydrocarbons such as cyclohexane; toluene, xylene, solvent naphtha, tetralin, dipentene, and the like. Aromatic hydrocarbons of; alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, butyl alcohol, isobutyl alcohol, s-butyl alcohol, cyclohexyl alcohol, 2-methylcyclohexyl alcohol, tridecyl alcohol; methyl acetate, ethyl acetate, isopropyl acetate Esters such as butyl acetate; Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methylcyclohexanone, diacetone alcohol, isophorone Glycols such as ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol; glycol ethers such as butyl cellosolve, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, diethylene glycol monobutyl ether; butyl cellosolve acetate, propylene glycol Examples include glycol ether esters such as monomethyl ether acetate, propylene glycol monoethyl ether acetate, and diethylene glycol monobutyl ether acetate; water and the like.
When the object to be removed is a screen printing ink, a medium boiling solvent (boiling point: about 120 to 230 ° C.) or a high boiling point solvent (boiling point: about 230 to 320 ° C.) is often used.
Further, examples of the solvent contained in the PDP phosphor paste include high-boiling solvents (boiling point: diethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate / diethylene glycol monobutyl ether [9/1 (weight ratio)]). About 230-320 ° C.).

In the cleaning method according to the present invention, the object to be removed is removed by pressing the cleaning sheet against the surface of the object to be cleaned. The method of pressing and removing (peeling) in the case of “pressing and removing the cleaning sheet” may be in accordance with the removal function inherent to the cleaning sheet to be used. Any pressing method may be used according to the original usage.
For example, the pressure-sensitive adhesive sheets of Patent Documents 1 and 2 are intended to [peel off] a removal target object due to adhesiveness, and have a high liquid absorbency intended to [suck off] the removal target object. Some cleaning sheets are designed to have In the case of such a cleaning sheet, the pressing method of the cleaning sheet may be simple pressing and peeling to the object to be cleaned. On the other hand, a composite member (Patent Document 3 or the like) (in which a porous layer (porous layer) such as a net is laminated on an adhesive layer) is also intended to be rubbed in addition to adhesiveness. In the case of a cleaning sheet intended for such [rubbing] or [wiping off], the surface of the object to be cleaned is moved while being rubbed after pressing the sheet surface against the object to be cleaned. It is necessary to add action. Such a usage of “pressing and rubbing the cleaning sheet” is also included in “pressing and removing the cleaning sheet” in the present invention.

In relation to the above pressing of the cleaning sheet, in the cleaning method according to the present invention, the pressing portion is moved with respect to the object to be cleaned, but the mode of movement is roughly divided into the following two types.
One is an aspect in which the adhesive roller rolls if only the pressing portion is seen. As shown in FIGS. 1 and 2, the point of action of the pressing force by the first member is applied to the object to be cleaned. However, the local movement of the cleaning sheet is such that it only contacts and leaves the object to be cleaned.
The other one is an aspect in the case where the object to be removed is scraped off by the cleaning sheet, and the point of action of the pressing force by the first member P1 is moved relative to the object to be cleaned S as shown in FIG. In this mode, the cleaning sheet 1A is also moved so as to rub against the object to be cleaned. This aspect is further divided into various operations depending on the relative feeding of the cleaning sheet with respect to the first member. From the point of constantly supplying a new cleaning sheet while enhancing the action of scraping off the object to be removed by the cleaning sheet, the cleaning sheet is moved toward the traveling direction of the first member as shown in FIG. The sending mode is preferred.

The first member, for example, a squeegee that is used as an instrument for directly scraping the object to be removed, and the pressing force necessary for the cleaning operation locally from the back over the entire width of the cleaning sheet. Any member having a shape, dimensions, hardness, and mechanical strength that can be applied to the cleaning sheet may be used.
From the viewpoint of moving the cleaning sheet relative to the first member, the first member is preferably appropriately rounded as shown in FIG. For example, the radius of curvature R1 is 5 mm to 100 mm, particularly 10 mm to 50 mm, which is suitable in that the pressing force can be applied intensively and does not hinder the feeding of the cleaning sheet.
Also, as shown in FIG. 1, the first member is in the form of a roller, so that the cleaning sheet can be fed more smoothly, and even when special feeding as shown in FIG. This is preferable because it assists in feeding the sheet.

  The pressing force of the first member, the feeding speed of the cleaning sheet, and the like may be appropriately set according to the type of cleaning sheet to be used, dimensional specifications of each part of the sheet, and economy.

The second member only needs to be configured so that at least the tip portion thereof can suppress the deformation of the object to be cleaned against the pressing force of the first member. What is necessary is just to design suitably the shape of the base part of a 2nd member, and the structure for further supporting this.
The second member does not necessarily need to locally contact the second surface of the object to be cleaned as shown in FIG. As shown in FIG. 3, the 2nd member P2 may support the 2nd surface of the to-be-cleaned body S in a wide range as an immovable rigid body with a wide pressing surface.

Considering the reduction in weight and volume of the entire cleaning device and the narrow space on the second surface side of current screen printing devices, the second member is locally on the second surface of the object to be cleaned. A mode in which the first member is moved in synchronization with the first member is compact and preferable.
In the case of a local mode, the second member may be a member having a shape, dimensions, hardness, and mechanical strength that can resist the pressing force.
In the case of a local mode, from the viewpoint of moving the second member relative to the object to be cleaned (for example, a screen printing plate), the second member is moderate as shown in FIG. The corners are preferably rounded. For example, the radius of curvature R2 is 5 mm to 100 mm, particularly about 10 mm to 50 mm, and is suitable in that it is easy to align with the first member and does not hinder relative movement with the object to be cleaned. is there.

In the case of the local mode, the second member rolls as a roller as shown in FIG. 1 and moves while rubbing in line contact with the object to be cleaned or as shown in FIG. 2 (b). It may be a mode of moving while. As the former specific member, a squeegee conventionally used for the first surface may be diverted.
Further, as shown in FIG. 2 (a), the second member may have a surface contact mode having a certain length with respect to the traveling direction, whereby the first member and the second member. It becomes easy to align the position.
In addition, when the second member is in the form of a roller, the cleaning sheet can be fed more smoothly, and if the rotational driving force is transmitted to the roller, in the case of a special form as shown in FIG. Also, the feeding of the cleaning sheet can be assisted.

As shown in FIG. 1, FIG. 2 (a), (b), FIG. 3, etc., whether a 1st member is made into the aspect of a roller, On the other hand, a 2nd member is a line contact-wide range. Any kind of contact and whether or not to use a roller may be freely combined.
Among these combinations, the combination in which the first member is a roller and the second member is a squeegee has an advantage that the increase in the weight and volume of the entire cleaning device can be reduced, which is preferable.

As described in the explanation of the background art, in the present invention, the screen printing plate is bent by pressing the first member, and the problem that the cleaning sheet does not uniformly contact the plate surface is found. This is suppressed by using the second member.
The important point here is to control the deflection that inhibits the uniform contact of the cleaning sheet to an appropriate small value, and the deflection of the screen printing plate must be adjusted to zero. is not.
Specifically, depending on the selection of the material of the second member, etc., the screen printing plate may be bent by being compressed by a small amount. In addition, it is more clean that intentionally providing such a small amount of deflection. May improve. Further, in some cases, the cleanliness may be improved by pressing the second member more strongly and displacing the second member toward the first member by a minute amount.
The minute balance position between the first member and the second member may be appropriately determined so that the cleanability is further improved according to the properties of the screen printing plate and the cleaning sheet.

The aspect of the cleaning sheet used in the present invention is not limited, and conventionally known cleaning sheets such as those shown in Patent Documents 1 to 3 may be used.
Here, the present invention proposes a new cleaning sheet that is configured not to use adhesiveness or the like as in a conventionally known cleaning sheet, but to be scraped off only by the unevenness of the sheet surface.
The cleaning sheet proposed here removes the object to be removed only by rubbing against the object to be cleaned, as shown in FIG. At least one surface is an objective surface to be rubbed against the object to be cleaned, and the objective surface is an uneven surface. Hereinafter, this cleaning sheet is also referred to as an “uneven sheet”. The concavo-convex sheet has an advantage that it can be cleaned regardless of the type of solvent contained in the object to be removed.
An outline of the structure of the uneven sheet will be described below. In the description, the concavo-convex sheet may be described as including a base sheet portion (referred to as a “base sheet portion”) and a convex portion provided on the upper surface thereof. However, the formation process is not limited. The concavo-convex sheet may be interpreted as having a concave portion provided on the original sheet surface and the remaining portion being a relatively convex portion. “Sheet” is a broad concept including “film”.

  As shown in FIG. 4, the concavo-convex sheet is an embodiment of a concavo-convex substrate in which convex portions 1 a are integrally formed on a base sheet portion B. The base sheet portion B and the convex portion 1a may be a laminate of different polymer layers. If the sheet having such a configuration is rubbed against the plate surface S1 of the screen printing plate S as shown in FIG. 6, only the back paste 201 can be scraped and removed by the convex portion 1a. As shown by 202, the paste taken by the convex portion 1a is accumulated in the concave portion 1b.

The material constituting the concavo-convex sheet is not particularly limited as long as it can be processed so that the objective surface becomes a concavo-convex surface. Depending on the type of the object to be cleaned, organic materials and inorganic materials may be used. Can be appropriately selected and used.
The concavo-convex sheet has an objective surface (upper surface of the sheet in the example shown in the figure) at least one surface of which is to be rubbed against the object to be cleaned, and the objective surface is constituted by the convex portion 1a and the concave portion 1b. It is sufficient that the surface is uneven. The concavo-convex sheet is generally used in a mode in which only one surface of the sheet is an objective surface, but both surfaces may be the objective surface depending on the application.

As shown in FIG. 6, a preferable use state of the uneven sheet is a state in which the peak portion is rubbed against the surface of the object to be cleaned while being largely curved using the first member (particularly, roller) P1. Therefore, the material constituting the concavo-convex sheet is preferably one having moderate flexibility and mechanical strength, and a polymer material is particularly preferred. The polymer material has an appropriate hardness so as not to damage the object to be cleaned such as a screen printing plate, and an appropriate amount so that the convex portion can be intimately adhered to the plate surface while being deformed appropriately when contacting the plate surface. Those having good elasticity are preferred. Such a polymer material is not particularly limited as long as it is various plastics, and examples thereof include polyethylene, polypropylene, vinyl chloride, polyamide, polyurethane, cellophane, and the like. These may be used alone or in combination of two or more. It can be used by mixing. Among these, various polyolefin-based resins including polyethylene are preferable materials in consideration of productivity, cost, processability of uneven surfaces, and the like. Examples of the polyolefin resin include polyethylene resins (for example, high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, ultra low density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer). Polymer, ethylene-propylene copolymer, and the like), polypropylene resins (for example, polypropylene and the like), thermoplastic elastomers, and the like. These resins may contain known additives such as pigments, filler antioxidants, and lubricants.
Moreover, as a structure of an uneven | corrugated sheet, either the single layer structure which consists of a single material as a whole, and the multilayer (lamination | stacking) structure comprised by the mutually different material layer may be sufficient.

The pattern drawn by the irregularities when the irregular surface of the irregular sheet is viewed is not particularly limited, and irregularities that appear to be randomly or regularly arranged convex or ridge-like convex parts on the flat base sheet part Examples thereof include a pattern and a concavo-convex pattern that appears as if single or ridge-line non-penetrating recesses are randomly or regularly arranged on the main surface of a flat sheet having the entire thickness of the concavo-convex sheet.
These are variations of various concavo-convex patterns, and the concavo-convex pattern that looks like a single concave portion may be interpreted as a pattern in which ridge line-shaped convex portions intersect in a mesh shape. The concavo-convex pattern that looks like a convex portion may be understood as a pattern in which groove-shaped concave portions intersect in a mesh shape.

It is preferable that the shape of the convex portion is a projection that exhibits a long continuous ridgeline shape (mountain shape) rather than a dot-like single projection, and the height thereof is constant. The convex portion acts as a blade of the wiper and can scrape off the removal target without leaving a trace.
Therefore, when a convex part is made into a ridgeline shape, the direction when a concavo-convex sheet is advanced while being rubbed against the surface of the object to be cleaned should be an angle with respect to the longitudinal direction of the ridgeline of the convex part.

If the concavo-convex sheet is a strip-shaped tape or the like and the direction of use is determined with respect to the outer shape of the tape, the longitudinal direction of the ridge-shaped convex portion is the traveling direction (the longitudinal direction of the tape in FIG. 5). On the other hand, the direction should be a right angle as shown in FIG. 5A, or a direction that forms an angle θ1 (0 ° <θ1 <180 °) other than a right angle as shown in FIG. 5B.
In an aspect having an angle θ1 other than a right angle, even if the width of the concave portion is widened, the bottom surface of the concave portion is difficult to come into contact with the object to be cleaned at the time of cleaning. preferable.
In this case, if the angle θ1 is defined on the acute angle side, 30 ° ≦ θ1 ≦ 90 °, particularly 45 ° ≦ θ1 ≦ 90 ° is a desirable range.

  There is no limitation on the pattern drawn by the unevenness when viewing the uneven surface of the uneven sheet, for example, a striped uneven pattern, a mesh-like uneven pattern, an arbitrary curve, a broken line regularly on the main surface of the base sheet part Or the uneven pattern disperse | distributed irregularly etc. are mentioned.

When the convex part is a ridge line shape, the convex part is the object to be cleaned, especially the cross-sectional shape when cut perpendicularly to the longitudinal direction of the ridge line of the convex part (hereinafter simply referred to as “cross-sectional shape”). This affects the effect of the edge when it touches the surface, the degree of bending, and the like, and thus greatly affects the removability of the object to be removed.
The cross-sectional shape of the convex portion may be appropriately determined according to the viscosity of the removal object to be removed and the mechanical characteristics of the material constituting the concave and convex sheet, for example, rectangular wave shape, sawtooth shape, triangular wave shape, semicircular shape A semi-elliptical shape is a preferable cross-sectional shape.
In the rectangular wave shape, since the shoulder edges of the protrusions are equal, the uneven sheet may be advanced in either the left or right direction in the figure. Further, since the width of the convex portion is substantially equal from the top portion to the base portion, the rigidity of the convex portion is relatively high, and a strong blade with little bending is obtained. On the other hand, the triangular wave shape has a feature that the tip portion of the convex portion is easily bent as compared with the rectangular wave shape, and accordingly, the unevenness of the plate surface is easily followed. In addition, if the convex portion has a triangular wave shape, there is an advantage that the volume of the concave portion is increased by the amount of the slope.

The width w1 of the ridge-line-shaped convex part having a rectangular wave-shaped cross section as shown in FIG. 4 is preferably in the range of about 10 μm to 2000 μm. Although it depends on the height h2 of the convex portion, when the width w1 is narrower than this, deformation such as bending becomes large and it becomes difficult to function as a blade. On the other hand, even if the width of the convex portion is wider than the above range, the upper surface of the rectangular wave-shaped convex portion does not contribute to the removal or holding of the object to be removed, which is useless.
Although a more preferable range of the width w1 of the convex portion varies depending on the evaluation method and application, it is 15 μm to 1000 μm, particularly 20 μm to 500 μm, especially 25 μm to 50 μm is effective for removing the PDP phosphor paste.

The height of the convex portion (h2 in FIG. 4) not only affects the degree of deformation of the convex portion, but also affects the capacity when collecting the removal object as the depth of the concave portion. It is preferable to determine in consideration of the feed amount.
The preferred height of the convex portion varies depending on the cross-sectional shape of the convex portion, but is preferably about 10 μm to 1000 μm when the cross-sectional shape is a rectangular wave shape. Although it varies depending on the evaluation method and application, a more preferable range of the height of the convex portion is 10 μm to 800 μm, and in particular, 13 μm to 500 μm is effective for removing the PDP phosphor paste, and there is no waste. In particular, 15 μm to 50 μm is a preferable range.
Further, the preferred ratio of the height of the convex portion to the total thickness of the sheet varies depending on the cross-sectional shape of the convex portion, the use of the sheet, the evaluation method of the cleanliness of the sheet, etc., but is preferably 10 to 90%. -85% is more preferable, especially 13-80% is effective for removing the PDP phosphor paste, and there is no waste. Among them, 15% -50% is a preferable range.

The width of the concave portion (w2 in FIG. 4) affects the capacity when storing the removal target together with the height h2 of the convex portion.
The preferable width of the concave portion varies depending on the cross-sectional shape of the concave portion. Although it depends on the height of the convex part (depth of the concave part), if the concave part width becomes narrower than this, the space for holding the scraped removal target becomes too small, and the amount of the target object to be removed is reduced. It becomes lower and cannot be completely removed. On the other hand, if the width of the concave portion is wider than the above range, the density of the convex portion becomes too coarse and the removability of the object to be removed decreases.
The more preferable range of the width w2 of the recess varies depending on the cross-sectional shape of the recess, the use of the sheet, the evaluation method of the cleanliness of the sheet, and the like, but is 5 μm to 3000 μm, and particularly 10 μm to 2000 μm is the PDP phosphor paste. It is effective for removal and has no waste. Among them, 15 μm to 150 μm is a preferable range.
The cross-sectional shape of the unevenness may be designed as appropriate, but the capacity of the recesses will be different if the cross-sectional shape is different.

In the above description, the preferable range of the width of the convex portion and the preferable range of the width of the concave portion are shown separately. However, in order to improve the actual sheet removal performance, the ratio of both in one pitch of the unevenness (or one occupation) Rate) and combinations of specific dimensions of the convex and concave widths are also important.
The ratio of the convex part width to the width of the concave / convex pitch is about 2% to 90%, and 5% to 85% is a more preferable range when the phosphor paste of PDP is to be removed.
Moreover, as a specific example of a preferable combination of the protrusion width w1 and the recess width w2 when the phosphor paste of the PDP is to be removed, (w1 = 50 μm, w2 = 150 μm), (w1 = 50 μm, w2 = 100 μm), (w1 = 25 μm, w2 = 75 μm), (w1 = 25 μm, w2 = 50 μm), and the like. These numerical values are an example on implementation, and do not limit the specifications of the concavo-convex sheet.
The thickness of the base sheet portion of the uneven sheet (h1 in FIG. 4) varies depending on the strength of the polymer material and the like, but is preferably in the range of about 20 μm to 1000 μm.

  Although there is no limitation in the manufacturing method of an uneven | corrugated sheet, resin molding methods, such as an extrusion system and a casting system, are mentioned, for example. More specifically, the resin in a molten state is pressed against a molding roll with concavo-convex sculpture to transfer the concavo-convex shape, or a plastic film is formed and then a concavo-convex roll is pressed. The method of forming is exemplified, and may be appropriately selected according to the shape of the target uneven portion.

An example of a cleaning method using an uneven sheet will be schematically described with reference to FIG.
On the first surface of the screen printing plate S (the surface in contact with the PDP phosphor layer forming substrate) S1, the back paste 201 has already been deposited. The objective surface (uneven surface) of the uneven sheet 1A is pressed against the first surface S1 by a roller P1 disposed as a first member behind the uneven sheet. On the other hand, on the second surface S2 of the screen printing plate S, the second member P2 is pressed against a region corresponding as a front-back relationship with the pressing region of the first surface.
The concavo-convex sheet 1A is fed from a lower left unwinding device (not shown) as shown by a thin arrow, passes over the roller R, and proceeds to a lower right winding device (not shown). Go. The roller P1 is preferably rotated in synchronism with the feed in order to assist the feeding of the sheet. However, even if the roller P1 is an active rotation accompanied by a power source, it is a rotation as a pulley that only follows the sheet. May be. The roller P1 itself moves in parallel to the right side of the drawing while pressing the sheet 1A against the plate surface of the screen printing plate, and one of the second members P2 is synchronized so as to always counteract the force of the roller P1. Translate to the right side of In this way, by moving the pressing portion of the cleaning sheet with respect to the object to be cleaned, harmful deflection of the screen printing plate S is suppressed, and the uneven surface of the uneven sheet 1A is turned around. While scraping off, the process proceeds to the right while touching the plate surface S1, and at the same time, a new sheet is always supplied.

  Performing a cleaning experiment in accordance with the cleaning method of the present invention, and performing a cleaning experiment in which the second member is not disposed on the back surface of the object to be cleaned while using the same cleaning sheet, to remove and remove the object to be removed. The amount of sheet consumption required was evaluated.

Example 1
In this example, an uneven sheet was used as the cleaning sheet. The form of the whole sheet is a web-like long sheet having a width of 160 mm as shown in FIG.
Regarding the dimensional specifications of the concavo-convex sheet, the widths of the concave portions and the convex portions (the dimensions in the longitudinal direction of the web) are a concave portion width of 140 μm, a convex portion width of 60 μm, and a convex portion height of 20 μm.

[Formation of uneven sheet]
Using a polyethylene resin with a density of 0.92 g / cm ³ , extrusion molding is performed with a T-shaped die at 190 ° C. to obtain a 150 μm-thick molten sheet, and the molten sheet is pressed with a concavo-convex squeeze roll and then solidified by cooling. A cleaning sheet having a rectangular corrugated cross section was obtained.
The concave / convex pattern is a stripe shape in which concave grooves and convex ridges are alternately arranged, and the direction in which the concave grooves and convex ridges extend is perpendicular to the longitudinal direction of the web (that is, the web width direction). .

In this embodiment, optimum values such as the pressing force of the first member and the feeding speed of the cleaning sheet are examined, or a cleaning experiment apparatus shown in FIG. 7 is manufactured as an apparatus for evaluating the cleanliness of the sheet. did.
In this cleaning experiment apparatus, an actual screen printing plate was used as the object to be cleaned. As shown in FIG. 8, this screen printing plate is obtained by diverting an actual screen member for forming a PDP phosphor layer to an experiment.
In a generally used screen printing apparatus, a cleaning experiment apparatus that has been pulled to the side between screen printing moves to the plate surface area and automatically wipes off the backside paste. The cleaning experiment apparatus shown in FIG. 7 changes the pressing conditions, the winding speed of the sheet, the overall traveling speed, the second member, etc. while reproducing the cleaning operation in such an actual machine. The cleaning conditions can be examined.
The specifications and experimental conditions of the cleaning experiment apparatus will be described below.

[Specifications of screen printing version]
FIG. 8 is a view of the plate surface of the screen printing plate used as the object to be cleaned. Main specifications such as dimensions, materials, and structures of each part are as follows.
Width a of opening of screen printing plate: 0.075 mm,
Opening pitch (period) b: 1.075 mm,
Total pattern area width c of the opening: 160 mm (size in the longitudinal direction of the opening 160 mm)
Dimension of one side inside frame (square) d: 280mm
Dimension e of outer side of frame (square): 320mm
Material of film part: Diazo-based photosensitive emulsion Material and wire diameter of cocoon (net part): Stainless steel, 20 μm
Bias: 22.5 degrees Tension: 0.85mm (measured with tension gauge STG75)
Film dough thickness: about 52 μm (wrinkle thickness about 42 μm, emulsion thickness about 10 μm)
The cleaning direction is a direction along the longitudinal direction of the opening, as indicated by an arrow in FIG.

[Overall configuration of cleanup experiment equipment]
FIG. 7 is a diagram showing a configuration of a main part of the cleaning experiment apparatus. The experimental apparatus is constructed on a pedestal that supports the entire apparatus. However, in order to show the internal structure, the pedestal is not shown in the figure but only suggested by a thick dashed line.
As shown in the figure, an opening is provided in the upper surface of the gantry, and a screen printing plate is set in the opening with the printing plate faced down, and the printing plate surface can be cleaned by a cleaning mechanism inside the gantry. . The structure related to the attachment / detachment of the screen printing plate is not shown.
Inside the gantry, the cleaning mechanism U1 is constructed on the slide mechanism U2 so that it can slide in the horizontal direction (left and right in the figure), and the objective surface of the cleaning sheet is pressed against the plate surface of the screen printing plate. In this state, the cleaning mechanism U1 itself can be moved forward while the sheet is fed forward (toward the right in the drawing) or backward.

On the back side of the screen printing plate, the second member P2 is held by the connecting member U3, and the second member P2 can slide integrally with the cleaning mechanism U1. With this configuration, the second member moves while rubbing the second surface of the screen printing plate in synchronization with the first member while resisting the force of the first member.
The connecting member U3 is an arm member having rigidity, but in FIG. 7, it is indicated by a thick one-dot chain line, and detailed illustration is omitted.

[Slide mechanism]
The slide mechanism U2 is a unit composed of a fixed portion U21 attached to the gantry and a movable portion U22 attached to the cleaning mechanism. Various types of slide mechanisms may be used, but in this cleaning experiment apparatus, a commercially available combination of a shaft (fixed part) and a linearly movable slide bearing (movable part) was used.
An electric motor (not shown) is used as a drive source for moving the cleaning mechanism U1 linearly (forward, backward), and the cleaning mechanism U1 can be freely controlled to stop, start, and move at a constant speed. .

[Cleaning mechanism]
The cleaning mechanism U1 is provided with a sheet feed mechanism for feeding the cleaning sheet A. The cleaning sheet A is moved from the unwinding roll (unwinding reel Z1) beyond the pressing roller Rx as the first member. The configuration is such that it is fed to a take-up roll (take-up reel Z2).
The form of the cleaning sheet A was a web having a width of 160 mm so that the entire width of the arrangement area of the openings of the screen printing plate was 160 mm. The width of the pressing roller Rx (distance between both end faces of the roller) was 200 mm in consideration of the width of the cleaning sheet A, and the roller radius was 17.5 mm.
The sheet feed drive source is an electric motor connected to the central shaft of the take-up reel Z2 via a transmission. The sheet feeding speed can be arbitrarily changed by adjusting the rotation speed of the electric motor with a transmission.

The pressing roller Rx and the unwinding reel Z1 are idle rotation rollers having no driving force.
The pressing roller Rx is attached to one end of the arm M, and the arm M can be rotated like a lever or a balance around the horizontal rotation axis Q. A weight G for adjusting the pressing load is attached to the end of the. With this configuration, the pressing roller Rx at the end of the arm can apply a pressing force according to the weight and position of the weight at the other end to the cleaning sheet A.
The weight G has a plurality of types of weights, and is configured to be able to finely adjust the position (center distance from the center axis of the arm) to be set on the arm. In this aspect, the load applied to the cleaning sheet A by the pressing roller Rx is directly measured by a push-pull gauge at the pressing point of the roller Rx, and is adjusted according to the total weight and position of the weight. The range of pressing load that can be set is 0 to 3.0 kg, and 2.6 kg was set in the experiment.

  The cleaning sheet feed speed (feed amount from the reel Z1) was 20 mm / sec. In addition, the moving speed of the entire cleaning mechanism U1 was 50 mm / sec. As a result, at the apex portion of the pressing roller Rx, the cleaning sheet is rubbed against the screen printing plate at a relative speed of 70 mm / second.

The above-mentioned setting of the cleaning sheet feed amount and the above-described setting of the moving speed of the entire cleaning mechanism are 40% of the consumption length of the cleaning sheet (sheet consumption) relative to the length of the cleaning area of the screen printing plate (160 mm) This is a setting that assumes the case of using (64 mm).
For example, if the feeding amount of the cleaning sheet is further increased, a larger amount of the cleaning sheet is consumed with respect to the same cleaning area, and the amount of paste accumulated in each concave portion is also reduced, so that the preferable value of the concave portion is also different. Come. There is no particular limitation on how much consumption is assumed to optimize the unevenness, but any consumption may be confirmed and determined one by one using this experimental apparatus. A sheet consumption of about 10% to 70%, especially a sheet consumption of about 40% assumed in the present cleaning experiment apparatus is economical in practical use and suitable for determining the actual unevenness range. .
In an actual cleaning experiment, the phosphor paste was applied to the plate surface side with a squeegee in order to reproduce the state where the paste was turned on the plate surface of the screen printing plate. The application region (= cleaning region) was a square region having a width of 160 mm and a length (dimension in the direction in which the cleaning sheet travels) 160 mm.

The tip portion Px of the second member P2 has its contact position with the back of the printing plate adjusted so as to suppress the displacement of the screen printing plate against the force of the pressing roller Rx, which is the first member. ing.
In the first embodiment, the second member is a squeegee. The material of the tip of the squeegee was urethane rubber, and the cross-sectional shape was rectangular.
The tip of the squeegee is slightly deflected by the pressing force from the first member, but sufficiently suppresses the large deflection of the screen printing plate that is a problem.
Various replacement parts such as a squeegee made of an elastic body, a squeegee made of a rigid body, a roller made of an elastic body, and a roller made of a rigid body were prepared for the second member P2 shown in FIG. These are detachable with respect to the connecting member U3 and have a replaceable structure.

[Implementation of cleaning method]
The screen printing plate described with reference to FIG. 8 was used as an object to be cleaned, and the phosphor paste was applied to the plate surface side with a squeegee in order to reproduce the reverse state. The application region was a rectangular region having a width of 160 mm and a length (dimension in the direction in which the cleaning sheet travels) 160 mm.

Using the above cleaning experimental apparatus, press the concave / convex sheet with a roller on the screen plate reproducing the back of the phosphor paste, and press it from the second surface side of the screen plate with a squeegee. A cleaning experiment was performed in which the phosphor paste was scraped off.
The evaluation of removability will be described later together with other examples and comparative examples.

Example 2
In this example, the squeegee as the second member of Example 1 was changed to a rubber roller (roller radius 17.5 mm, rubber part thickness 3 mm, roller shaft part is metal). A cleaning experiment was conducted in the same manner as in Example 1.

Example 3
In this example, a cleaning experiment was conducted in the same manner as in Example 1 except that the squeegee of Example 1 was changed to a metal roller (roller radius: 17.5 mm).

Comparative Example 1
A cleaning experiment was conducted in the same manner as in Example 1 except that the squeegee as the second member in Example 1 was not used (pressed only by the first member).
This comparative example is a prior art except that the uneven sheet recommended in the present invention is used.

Comparative Example 2
In this comparative example, a cleaning experiment was performed in which adhesive sheets were sequentially attached and peeled off. In this experiment, since a rubbing operation was not performed, a cleaning experiment device dedicated to an adhesive sheet was manufactured.
[Formation of adhesive sheet]
On one side of a polyethylene film (base material) having a thickness of 0.10 mm, 100 parts by weight of an acrylic adhesive [a copolymer of butyl acrylate / acrylonitrile / acrylic acid (weight ratio: 90/10/2)] What added 15 weight part of crosslinking agents was apply | coated and dried so that the thickness after drying might be 13 micrometers, and the adhesive sheet was obtained.
The form of the whole pressure-sensitive adhesive sheet is a web-like long sheet having a width of 160 mm, similar to the concavo-convex sheet used in Example 1.
[Production of clean experiment equipment]
A cleaning experiment apparatus shown in FIG. 11 was manufactured for a cleaning experiment using an adhesive sheet. The roller for pressing the adhesive sheet was made of metal with a radius of 17.5 mm and moved along the screen printing plate surface at a speed of 100 mm / second. The roller is a pulley that only rotates along the adhesive sheet, and has no driving force to feed the adhesive sheet to itself.
The consumption of the pressure-sensitive adhesive sheet is the same as that applied to the entire application area and peeled off, so the consumption is 100%.

〔Evaluation methods〕
Each of the example products 1 to 3 and the comparative examples 1 and 2 was evaluated for the sheet usage, paste removability, and comprehensive evaluation.
Whether or not the paste remained on the screen printing plate was checked with a digital microscope and judged. The paste removability is “O” if the backside paste is removed by 70% or more, and “△” if the backside paste is removed in the range of 40% or more and less than 70%, and the backside paste. If the removal of was less than 40%, it was rated as “x”.
The amount of the cleaning sheet used was adjusted so that the concavo-convex sheet and the polyester cloth were consumed 40% of the cleaning area of 160 mm. About an adhesive sheet, consumption is 100% as above-mentioned.
Comprehensive evaluation was determined based on whether the removability was good or not and the amount of consumption was good.

As is clear from Table 1 above, all of Examples 1 to 3 and Comparative Example 2 were good in terms of paste removability. However, while the sheet usage of Examples 1 to 3 was half of the clean area, Comparative Example 2 is an adhesive type, so the sheet usage is the same as the clean area. It was found that it was uneconomical compared to the product of the example and could not be said to be good as a comprehensive evaluation.
Further, it was found that in Comparative Example 1 in which there was no pressing from the opposite surface side of the screen plate when cleaning, a part of the paste remaining was removed, and it could not be said that the removal was good.

The cleaning sheet of the present invention is used for cleaning (removing) various objects to be removed such as paste and ink attached to the object to be cleaned, and in particular, various types represented by a plasma display panel (PDP). In the production of a phosphor layer to be incorporated in a flat panel display, it can be suitably used as a cleaning sheet for wiping off the paste behind the objective surface of the screen printing plate.
According to the present invention, it has been found that the paste behind the screen printing plate can be removed effectively and with a small amount of use.

It is a schematic diagram for demonstrating the cleaning method of this invention. It is a schematic diagram for demonstrating the other aspect of the cleaning method of this invention. It is a schematic diagram for demonstrating the other aspect of the cleaning method of this invention. It is the figure which showed the structure of the uneven | corrugated sheet proposed as a preferable cleaning sheet in this invention. It is the figure which showed the aspect of the uneven | corrugated sheet proposed in this invention. It is a figure which shows an example of the cleaning method using an uneven | corrugated sheet. It is the figure which showed the structure of the principal part of the cleaning experiment apparatus produced as an evaluation apparatus for investigating optimal values, such as pressing force of a 1st member, and the feed speed of the cleaning sheet. It is the figure which looked at the plate surface of the screen printing plate used as a to-be-cleaned body in the cleaning experiment apparatus of FIG. It is sectional drawing which shows typically the arrangement structure of the fluorescent substance in the manufacturing process of the fluorescent substance layer of the conventional PDP, and its manufacturing method. Each phosphor R, G, B is disposed in a groove extending perpendicular to the paper surface. It is the schematic diagram which showed partially the plate surface of the screen printing plate used for manufacture of the fluorescent substance layer of PDP. It is a figure which shows the structure of the conventional cleaning apparatus using an adhesive sheet. It is a figure explaining the nonuniformity of a removal property and the cause when a cleaning sheet is simply pressed from one side as in the past.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cleaning sheet 201 Object to be removed S To-be-cleaned object S1 First surface of to-be-cleaned object S2 Second surface of to-be-cleaned object P1 First member P2 First member

Claims (6)

A removal object attached to the first surface of the object to be cleaned, which is a flexible sheet-like material, is a method of removing the object by pressing the cleaning sheet against the surface,
By pressing the first member from behind the cleaning sheet, the cleaning sheet is locally pressed against the first surface of the cleaning object, and the object to be cleaned is pressed against the pressed area. While the second member is pressed against the corresponding area on the second surface of the second surface, the pressing portion of the cleaning sheet is moved relative to the object to be cleaned, and the object to be removed is transferred to the cleaning sheet. A cleaning method, characterized by taking.   The cleaning method according to claim 1, wherein the first member is a roller.   The cleaning method according to claim 1 or 2, wherein the second member is a squeegee.   The cleaning method according to claim 1, wherein the second member is a roller.   The cleaning sheet is formed so as to remove the object to be removed by rubbing against the object to be cleaned, and at least one surface of the cleaning sheet is an object surface to be rubbed against the object to be cleaned The cleaning method according to claim 1, wherein the objective surface is an uneven surface.   The cleaning method according to claim 1, wherein the object to be cleaned is a screen printing plate for forming a phosphor layer of a plasma display panel.

Images