JP2010058040A - Cleaning film and cleaning method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning film and a cleaning method which enable removing foreign matter by following even minute irregularities, in removing foreign matter on the surface of a substrate having minute irregularities. <P>SOLUTION: The cleaning film includes at least one adhesive layer on a base material, and the adhesive layer contains at least one swellable gel. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cleaning film used for removing foreign matter from a substrate having fine irregularities such as a printed circuit board or a conductive pattern material, and a cleaning method using the same.

  Deposits such as oil and foreign matter left behind during processing of printed circuit boards and conductive pattern materials used in liquid crystal displays, electroluminescent displays, plasma displays, electrochromic displays, solar cells, electronic paper, etc. It can induce significant contamination and result in degraded performance and durability of the final product. Therefore, in order to remove contaminants on the surface, a combination of Freon (registered trademark) cleaning, ultrasonic cleaning using ultrapure water, activator solution cleaning, acid / alkali cleaning, etc. may be combined as necessary. Repeatedly wash thoroughly.

  However, these wet cleaning processes have a long processing time, use a large amount of water, and have a large device space. It has become apparent.

  In order to solve these problems of wet cleaning, dry processes using various adhesive cleaning rollers and cleaning sheets have been studied. For example, a cleaning sheet in which a curable pressure-sensitive adhesive that can be cured by integrating the adhesive and the pressure-sensitive adhesive component is attached to a portion of the article where there is a surface-adhered material is attached to the support, A method is known in which an agent component is integrated and cured, and the cured cleaning sheet is peeled off from the article, so that the sheet and the surface deposit are integrally removed from the article (see, for example, Patent Document 1).

  However, when the cleaning sheet described in Patent Document 1 is used for cleaning a printed circuit board having a lot of fine irregularities, the follow-up to fine irregularities is inferior and sufficient cleaning properties are not obtained. It has been found that there is a risk of damaging the printed circuit board.

  It is known to use an adhesive dust cleaner that has an adhesive layer that contains a foaming agent on a substrate that has good conformability to the uneven surface of the dust removal object for cleaning dust removal objects with an uneven surface. (For example, refer to Patent Document 2). There is a known method of removing dirt such as dust and dirt on the surface of an uneven electronic substrate, etc., with a cleaning roller having a thin-walled adhesive layer and an inner soft elastic layer having a thick-layer structure (for example, an uneven electronic substrate) (See Patent Document 3).

  However, it has been found that neither the adhesive dust cleaner described in Patent Document 2 nor the cleaning roller described in Patent Document 3 has sufficient cleaning performance for further high definition.

Under these circumstances, it is desired to develop a cleaning film and a cleaning method capable of following the fine irregularities and removing the foreign substances when removing the foreign substances on the surface of the substrate having fine irregularities.
JP 7-155704 A JP 2006-75502 A JP 2007-175473 A

  The present invention has been made in view of the above situation, and the purpose thereof is to remove foreign matter following the fine unevenness when removing the foreign matter on the surface of the substrate having fine unevenness. It is to provide a cleaning film and a cleaning method.

  The inventors of the present application have found that a pressure-sensitive adhesive layer containing a swellable gel is important in the process of earnestly studying to solve the above-described problems, particularly in the cleaning of uneven surfaces such as printed boards. This is because the swollen pressure-sensitive adhesive layer itself follows the fine irregularities and covers and entangles foreign matter, but it also leaves a small amount of moisture remaining on the surface to form a film, allowing it to remain attached for a long time. Even in this case, the present inventors have found that no adhesive residue is produced on the surface of the printed circuit board, resulting in the present invention. The above object of the present invention has been achieved by the following constitution.

  The above object of the present invention has been achieved by the following constitution.

  1. A cleaning film having at least one pressure-sensitive adhesive layer on a support, wherein the pressure-sensitive adhesive layer contains at least one swellable gel.

  2. 2. The cleaning film as described in 1 above, wherein the pressure-sensitive adhesive layer contains 50 to 100 parts by mass of a swellable gel.

  3. 3. The cleaning film as described in 1 or 2 above, wherein the swellable gel is a hydrogel.

  4). 4. The cleaning film according to any one of 1 to 3, wherein the pressure-sensitive adhesive layer has a thickness before swelling of 0.05 μm to 10 μm.

  5. A cleaning method for cleaning the surface of a substrate having fine irregularities with a cleaning film, wherein the cleaning film uses the cleaning film according to any one of 1 to 4 above.

  6). 6. The cleaning method according to 5 above, wherein when the cleaning film is used, the cleaning film is preliminarily made to contain moisture.

  7). 7. The cleaning method as described in 6 above, wherein the amount of water is 0.1 ml / g to 10.0 ml / g.

  8). The cleaning method according to any one of 5 to 7, wherein the base material is a printed circuit board.

  It was possible to provide a cleaning film and a cleaning method that can remove foreign matters following fine irregularities when removing foreign matters on the surface of a substrate having fine irregularities.

  Embodiments of the present invention will be described with reference to FIGS. 1 and 2, but the present invention is not limited thereto.

  FIG. 1 is a schematic sectional view of the cleaning film of the present invention.

  The cleaning film shown in FIG.

  In the figure, 1a indicates a cleaning film. The cleaning film 1a includes a support 101 and an adhesive layer 102 containing a swellable gel.

  The cleaning film shown in FIG.

  In the figure, 1b indicates a cleaning film. The cleaning film 1b has a structure including a support 101, a pressure-sensitive adhesive layer 102 containing a swellable gel, and an easy-adhesion layer 103.

  The cleaning film shown in (c) will be described.

  In the figure, 1c indicates a cleaning film. The cleaning film 1c includes a support 101, an adhesive layer 102 containing a swellable gel, an easy adhesion layer 103, and a functional layer 104. Examples of the functional layer 104 include an antistatic layer and a humectant layer.

  Next, the adhesive layer of the cleaning film shown in (a) to (c) will be described.

The structural example of the adhesive layer of the cleaning film shown by (a)-(c) is shown below.
1. 1. Single swellable gel 2. Consists of a plurality of swellable gels 3. Consist of a mixture of swellable gel and non-swellable gel Consists of multiple layers: Consists of at least two layers, examples of which are shown below.
1) A single swellable gel is used for the upper and lower layers.
2) A plurality of different swellable gels are used in the upper and lower layers.
3) The upper layer is composed of a single swellable gel, and the lower layer is composed of a plurality of swellable gels.
4) The upper layer is composed of a plurality of swellable gels, and the lower layer is composed of a mixture of a swellable gel and a non-swellable gel.
5) The upper layer is composed of a single swellable gel, and the lower layer is composed of a mixture of a swellable gel and a non-swellable gel.

  The pressure-sensitive adhesive layer only needs to contain a swellable gel, and in addition to the swellable gel, additives such as a surfactant, a pH adjuster, and latex may be added as necessary. The thickness of the pressure-sensitive adhesive layer before swelling is preferably 0.05 μm to 10 μm, more preferably 0.1 μm, taking into account the removal of foreign matters, the ability to follow fine irregularities, the ease of application to a substrate, and the like. ˜5 μm is preferred.

  The thickness is a value obtained by cutting the produced cleaning film with a microtome and observing the cut surface with a transmission electron microscope.

  The swellable gel contained in the pressure-sensitive adhesive layer is preferably 50 parts by mass to 100 parts by mass, more preferably 70 parts by mass to 100 parts by mass in consideration of swelling properties, adhesiveness, moisture retention performance, and the like.

  FIG. 2 is a schematic diagram of a printed circuit board as an example of a substrate having fine irregularities. FIG. 2A is a schematic plan view of a printed circuit board as an example of a substrate having fine irregularities. FIG. 2B is an enlarged schematic view of a portion indicated by P in FIG. FIG. 2C is an enlarged schematic cross-sectional view along AA ′ of FIG.

  In the figure, 2 indicates a printed circuit board. 202a indicates a horizontal line formed on the support 201, and 202b indicates a vertical line formed on the support 201. Usually, the horizontal line 202a and the vertical line 202b are composed of a plurality of lines, and this figure shows a case where both are composed of 10 lines.

  E1 indicates the distance between the lines constituting the horizontal line 202a. The distance E1 is preferably 1 μm to 30 μm. E2 indicates the distance between the lines constituting the vertical line 202b. The distance E2 is preferably 1 μm to 30 μm.

  F indicates the width of a line constituting the vertical line 202b. The width F is preferably 1 μm to 30 μm. Similarly, the width of the line constituting the horizontal line 202a is preferably 1 μm to 30 μm.

  G indicates the thickness of the line from the support 201. The thickness G is determined from the desired conductivity, the cross-sectional area of the line, and the length, and is preferably 1 μm to 100 μm. In recent years, there has been an increasing demand for miniaturization of printed circuit boards with a line width and line spacing of 20 μm or less, particularly 10 μm or less, and the required thickness is 5 μm to 15 μm.

  In the present invention, the substrate having fine unevenness includes a substrate having an uneven structure as shown in the figure.

  In the present invention, the phrase “containing a swellable gel” includes a state where the pressure-sensitive adhesive layer is composed of a swellable gel and a state where a swellable gel and a non-swellable gel are mixed.

  The swellable gel used in the present invention is preferably a hydrogel. Examples of the dispersoid include gelatin and agar. Of these, gelatin is preferred. The gelatin is preferably extracted from pig skin, beef bone or the like, and may be acid-treated gelatin or alkali-treated gelatin, or gelatin modified with phthalic acid or the like may be used. These dispersoids can be used alone or in combination. When gelatin is used as the dispersoid, a hardener may be added. As the hardener, vinyl sulfone type, epoxy type, acrylamide type and the like are used, and vinyl sulfone type is more preferable.

  Moreover, it is also possible to mix and use said swellable gel and water-absorbing resin. The water-absorbing resin is not particularly limited. For example, sodium polyacrylate resin, marketed product (for example, SS gel manufactured by Sumitomo Seika Co., Ltd., high water-absorbing resin Aquakeep, manufactured by Advanced Soft Materials Co., Ltd.) Slide ring gel WA-GEL, Topy Industries, Ltd. swelling mica) and the like.

(Support)
Preferred examples of the support include a resin plate and a resin film. There is no limitation in resin, It can select suitably from well-known things. For example, polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate, polyolefins such as polyethylene (PE), polypropylene (PP), polystyrene, and cyclic olefin resins, vinyl resins such as polyvinyl chloride and polyvinylidene chloride, Single-layer or multiple-layer substrates such as polyether ether ketone (PEEK), polysulfone (PSF), polyether sulfone (PES), polycarbonate (PC), polyamide, polyimide, acrylic resin, triacetyl cellulose (TAC) A film is preferably used. Further, a glass substrate or paper can be used. Among these, from the viewpoint of ease of handling and cost, a biaxially stretched polyethylene terephthalate film, a polyethylene film, and a triacetyl cellulose film are preferable.

  The thickness of the support is preferably from 10 to 500 μm, more preferably from 30 to 100 μm, in consideration of followability to fine irregularities, ease of handling, cost, and the like.

  The film support is preferably provided with a surface treatment or an easy adhesion layer in order to ensure the wettability and adhesion of the coating solution. A conventionally well-known technique can be used about a surface treatment or an easily bonding layer. The easy-adhesion layer may be a single layer, but may be composed of two or more layers in order to improve adhesion.

  It is also possible to laminate an antistatic layer, a cushion layer, a moisturizing layer or the like on the easy adhesion layer.

  Examples of the surface treatment method include atmospheric pressure plasma treatment, corona discharge treatment, and etching treatment.

  The easy adhesion layer can be formed by applying, for example, a latex anchor coating agent.

  The antistatic layer may be a layer containing an antistatic agent or conductive fine particles, and examples of the antistatic agent include cationic antistatic agents such as quaternary ammonium salts, imidazolines and sulfonium salts, alkyl sulfates, alkyl sulfates, and the like. Anionic antistatic agents such as phosphate, nonionic antistatic agents such as sorbitan, amine and amide, amphoteric antistatic agents such as sulfobetaine, amine oxide, and phosphate can be used. For example, metal fine particles such as tin oxide can be used.

  The moisture retaining layer only needs to be able to retain moisture. For example, the moisture retaining layer may contain the above water-absorbing resin, or glycerin or ethylene glycol may be used.

(Cleaning film production method)
The cleaning film of the present invention is a support in which a pressure-sensitive adhesive layer-forming coating solution containing a swellable gel (hereinafter referred to as a coating solution) is applied on a support whose surface is treated, or an easy-adhesion layer is provided. It can be produced by applying on the easy-adhesion layer of the body or applying on the functional layer of the support provided with the easy-adhesion layer / functional layer and then drying.

  The method for applying the coating liquid on the support is not particularly limited. For example, a roll coating method, a bar coating method, a dip coating method, a spin coating method, a casting method, a die coating method, a blade coating method, a bar coating method, Gravure coating method, curtain coating method, spray coating method, doctor coating method, etc., letterpress (letter) printing method, stencil (screen) printing method, planographic (offset) printing method, intaglio (gravure) printing method, spray Examples of the printing method include a printing method and an inkjet printing method.

  In order to improve coatability, it is preferable to add a surfactant to the coating solution. Examples of the surfactant include generally known anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, and the like. It is possible to use. In the present invention, after the cleaning film bonded to the base material is peeled off, after the cleaning film is manufactured or the base material is bonded to the base material in order to prevent additives such as an activator from being transferred onto the base material. Prior to use, it is preferable to wash in advance with ultrapure water or the like.

[Cleaning method]
As the cleaning method of the present invention, it is preferable to add moisture to the pressure-sensitive adhesive layer containing the swellable gel in advance before attaching the cleaning film of the present invention to the substrate.

  The amount of moisture is preferably 0.1 ml / g to 10 ml / g per gram of swellable gel in consideration of the ability to follow uneven portions, peelability from the substrate, prevention of contamination of the substrate, and the like. 0.3 ml / g to 3 ml / g are preferred.

  As a method of preliminarily containing moisture, a cleaning film having an adhesive layer may be immersed in water, applied with a brush or a bar coater, sprayed with spray or steam, etc. As a method of giving moisture, a method of spraying or spraying steam is more preferable.

  It is preferable to use ultrapure water as the water content. It is also preferable to use a certain amount of warm water in order to improve the adhesion at the time of attaching the film substrate. The temperature of the hot water used is preferably 25 ° C. to 50 ° C. in consideration of the solubility and swelling properties of the pressure-sensitive adhesive layer.

  Furthermore, the moisture added in advance may contain a hardening agent such as gelatin, a pH adjuster, a surfactant and the like.

  Including moisture, the adhesive layer is swollen, and the adhesive strength of the adhesive layer during use is preferably 0.01 N / 25 mm to 5.0 N / 25 mm in consideration of compatibility between removal of foreign matters and prevention of adhesive residue, etc. 0.03 N / 25 mm to 2.0 N / 25 mm is preferable. In addition, adhesive force shows the value measured according to JISZ1528.

  When the cleaning film is bonded to the surface of the substrate, it is preferable to use a pressure roll, a thermal laminator, or the like in order to improve the adhesion.

(Base material)
The target substrate is not particularly limited. For example, printed circuit boards, diodes, transistors, magnetic heads, ceramic applied elements used in liquid crystal displays, electroluminescence displays, plasma displays, electrochromic displays, solar cells, electronic papers, etc. Examples thereof include a substrate having fine irregularities on the surface of an electronic component such as a film, a plastic molded product, and a metal plate.

  The cleaning film of the present invention can also be used for protecting the surface of a substrate. For example, after laminating the cleaning film of the present invention on the surface of the printed circuit board, the film is transferred to the next process in the bonded state, and then the cleaning film is peeled off to clean the printed circuit board and adhere foreign matter during the transfer. It is possible to prevent the surface and the surface from being scratched.

  After transferring to the next process in the pasted state, the period until peeling takes into account failure prevention due to transfer adhesion of the pressure-sensitive adhesive layer to the base material. It is preferable to select appropriately. The storage conditions until the cleaning film is peeled off may be arbitrary, but in addition to the purpose of preventing the transfer of the adhesive to the base material, in order to maintain the performance of the substrate itself, it should be stored in a low temperature and low humidity state to some extent. Is preferred.

  In particular, when used in such a manner as to be stored for a certain period of time until peeling after bonding, it is preferable to add a hardening agent in order to prevent transfer of the pressure-sensitive adhesive layer. As the hardener, vinyl sulfone type, epoxy type, acrylamide type and the like are used, and vinyl sulfone type is more preferable.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited to this. In addition, although the display of "%" is used in an Example, unless otherwise indicated, "mass%" is represented.

Example 1
(Preparation of support)
A polyester film having a thickness of 50 μm and a width of 180 mm prepared by corona discharge treatment at 10 W / (m ² · min) was prepared.

(Formation of easy adhesion layer)
On the prepared support, the following undercoat coating solution was applied by a die coating method to a dry film thickness of 0.4 μm and dried to form an easy-adhesion layer.

(Undercoat liquid)
Copolymer latex liquid (solid content 30%) of butyl acrylate 30% by mass, t-butyl acrylate 20% by mass, styrene 25% by mass, 2-hydroxyethyl acrylate 25% by mass 50 g
Hexamethylene-1,6-bis (ethyleneurea) 0.05g
Finish up to 1000 ml with water.

Preparation of coating solution for forming an adhesive layer As shown in Table 1, a coating solution for forming an adhesive layer with different dispersoids was prepared. 1-1-No. 1-5.

Application liquid No. for pressure-sensitive adhesive layer formation Preparation of 1-1 Alkali-treated beef bone gelatin (manufactured by Nitta Gelatin Co., Ltd.) 2 parts by mass Surfactant (S-1) 4% aqueous solution 1.0 part by mass Hardener (H-1) 0.5% Aqueous solution 2.5 parts by mass Ultrapure water 94.5 parts by mass Adhesive layer forming coating solution No. Preparation of 1-2 Acid-treated pig skin gelatin (manufactured by Nitta Gelatin Co., Ltd.) 3.0 parts by mass Surfactant (S-1) 4% aqueous solution 1.0 part by mass Hardener (H-1) 0. 5% aqueous solution 4.0 parts by mass Ultrapure water 92.0 parts by mass Preparation of 1-3 Agar 2.5 parts by weight Surfactant (S-1) 4% aqueous solution 1.0 part by weight Ultrapure water 96.5 parts by weight Coating liquid No. Preparation of 1-4 Acid-treated pork skin gelatin (manufactured by Nitta Gelatin Co., Ltd.) 2.0 parts by weight Agar 1.0 part by weight Surfactant (S-1) 4% aqueous solution 1.0 part by weight Hardener ( H-1) 0.5% aqueous solution 2.5 parts by mass Ultrapure water 93.5 parts by mass Adhesive layer forming coating solution No. Preparation of 1-5 Acid-treated pork skin gelatin (Nitta Gelatin Co., Ltd.) 2.0 parts by mass Superabsorbent resin Aqua Keep (Sumitomo Seika Co., Ltd.) 0.5 parts by mass Surfactant (S- 1) 4% aqueous solution 1.0 part by mass Hardener (H-1) 0.5% aqueous solution 2.5 part by mass Ultrapure water 94.0 parts by mass

(Production of cleaning film)
On the easy-adhesive layer of the support on which the prepared easy-adhesive layer was formed, the prepared coating liquid No. 1-1 to 1-5 were applied by a die coating method, dried, washed for 15 minutes in running water of ultrapure water at 25 ° C., and then dried to have a 0.2 μm thick adhesive layer. A film was prepared and no. 101-105. The thickness indicates a value obtained by cutting the cleaning film with a microtome and observing the cut surface with a transmission electron microscope.

(Preparation of comparative cleaning film)
Cut out the adhesive sheet of the high-function dust removing adhesive roll cleaner SDR10 manufactured by Nitto Denko Co., Ltd. 106.

  Sanite Chemical PAC-3-50THK manufactured by Sanei Kaken was used as a comparative cleaning film. 107.

(Preparation of substrate for cleaning)
ITO (Indium Tin Oxide) is produced on polyethylene terephthalate with a thickness of 50 μm by sputtering, and 10 lines of 10 μm in depth, line width and line spacing as shown in FIG. A printed circuit board etched into a grid pattern was prepared as a cleaning substrate.

Evaluation Each cleaning film No. Table 2 shows the results of testing the foreign matter removal properties and adhesive residue properties of 101 to 107 by the methods shown below and evaluating according to the evaluation rank shown below.

Test method for removal of foreign matter 0.5 ml of ultrapure water per 1 g of swellable gel was applied to the adhesive layer of the cleaning film, swollen and then bonded to the prepared cleaning substrate, and laminator LPD3216 manufactured by Fuji Plastics Co., Ltd. The film was pasted twice at 100 ° C., left at room temperature for 4 hours, and left for 1 week, and then the cleaning film was peeled off. Thereafter, the substrate for cleaning is immersed in a glass beaker containing 500 ml of ultrapure water, washed with an ultrasonic cleaner for 10 minutes, and this solution is 0.2 μm with a particle counter (KS-42) manufactured by Rion Co., Ltd. Detergency was evaluated by measuring the number of particles. In addition, when the same evaluation was performed on the printed circuit board for cleaning before the cleaning film was attached, the number of particles was approximately 1500.

Evaluation rank of foreign matter removability ◎: Number of particles less than 100 ○: Number of particles less than 300, 100 or less △: Number of particles less than 500, 300 or less ×: Number of particles 500 or more Adhesive residual test method Cleaning film Using a scanning electron microscope (S-5000H, manufactured by Hitachi, Ltd.), the surface of the cleaning printed board after peeling was photographed at any five locations at a magnification of 2,000 to examine the state of the remaining adhesive.

Adhesive residue evaluation rank ◎: No adhesive residue left in 5 observed locations ○: Slight adhesive remains in 1 location out of 5 observed locations △: 2 to 4 in 5 observed locations Adhesive remains at the location ×: The adhesive is transferred at 5 locations out of 5 observed locations

  The cleaning film No. 1 of the present invention. By using 101 to 105, no adhesive remained on the substrate having fine irregularities, and excellent foreign matter removability was exhibited. In addition, since there was no adhesive remaining on the substrate even after standing for 1 week, it was confirmed that it could be used as a protective film on the substrate. The comparative cleaning film No. No. 106 had excellent foreign matter removability, but a large amount of adhesive remained. The comparative cleaning film No. No. 107 had no adhesive remaining, but resulted in poor foreign matter removal. The effectiveness of the present invention was confirmed.

Example 2
(Preparation of support)
The same support as in Example 1 was prepared.

(Formation of easy adhesion layer)
The same easy adhesion layer as Example 1 was formed on the prepared support.

(Production of cleaning film)
The cleaning film No. 1 of Example 1 was used. 1-1 was produced in the same manner as in Example 1.

(Preparation of printed circuit board for cleaning)
The same printed circuit board for cleaning as in Example 1 was prepared in the same manner as in Example 1.

Evaluation A test in which the amount of water applied to the pressure-sensitive adhesive layer of the cleaning film prepared for the purpose shown in Table 3 was changed was determined as Test No. Table 3 shows the results obtained by testing the prepared cleaning substrates for foreign matter removal and pressure-sensitive adhesive residue by the same method as in Example 1 and evaluating according to the same evaluation rank as in Example 1.

  Using the cleaning film of the present invention, if the amount of water applied to the pressure-sensitive adhesive layer is in the range of 0.1 ml / g to 10 ml / g, no adhesive remains on the substrate having fine irregularities, Excellent foreign matter removal performance was exhibited. In addition, since there was little adhesive remaining on the substrate even after standing for 1 week, it was confirmed that it could be used as a protective film on the substrate. The effectiveness of the present invention was confirmed.

Example 3
(Preparation of support)
The same support as in Example 1 was prepared.

(Production of cleaning film)
As shown in Table 4, the cleaning film No. 1 prepared in Example 1 was the same except that the thickness of the pressure-sensitive adhesive layer was changed. The same cleaning film as in 1-1 was prepared and No. 1 was prepared. 301 to 309.

(Preparation of substrate for cleaning)
The same cleaning substrate as in Example 1 was prepared.

Evaluation Each cleaning film No. Table 4 shows the results of examining the foreign matter removal property and adhesive remaining property of 301 to 309 by the same method as in Example 1 and evaluating according to the same evaluation rank as in Example 1.

  When the cleaning film of the present invention is used and the thickness of the pressure-sensitive adhesive layer is in the range of 0.05 μm to 10.0 μm, no adhesive remains on the substrate having fine irregularities, and excellent foreign matter removability showed that. In addition, since there was no adhesive remaining on the substrate even after standing for 1 week, it was confirmed that it could be used as a protective film on the substrate. The effectiveness of the present invention was confirmed.

Example 4
(Preparation of support)
The same support as in Example 1 was prepared.

(Preparation of adhesive layer forming coating solution)
As shown in Table 5, the adhesive layer-forming coating was prepared by changing the ratio of the superabsorbent resin Aquakeep (manufactured by Sumitomo Seika Co., Ltd.) and acid-treated pork skin gelatin (manufactured by Nitta Gelatin Co., Ltd.). Liquid No. The cleaning film No. 1 prepared in Example 1 was used except that 4-1 to 4-3 were used. A cleaning film was prepared by the same method as in Nos. 1-5 and No. 1-5. 401-403.

Evaluation Each cleaning film No. Table 6 shows the results obtained by testing the foreign matter removing properties and adhesive remaining properties of 401 to 403 by the same method as in Example 1 and evaluating according to the same evaluation rank as in Example 1.

  Sample No. 1 of Example 1 101 (gelatin content ratio 100%), 105 (gelatin content ratio 80%) and the results shown in Table 6, using the cleaning film of the present invention, the hydrogel dispersoid content of the pressure-sensitive adhesive layer is 50 parts by mass to Within the range of 100 parts by mass, no adhesive remained on the substrate having fine irregularities, and excellent foreign matter removability was exhibited. In addition, since there was no adhesive remaining on the substrate even after standing for 1 week, it was confirmed that it could be used as a protective film on the substrate. The effectiveness of the present invention was confirmed.

It is a schematic sectional drawing of the cleaning film of this invention. It is a mimetic diagram of a printed circuit board as an example of a substrate which has fine unevenness.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a-1c Cleaning film 101 Support body 102 Adhesive layer 103 Easy-adhesion layer 104 Functional layer 2 Printed circuit board 201 Support body 202a Horizontal line 202b Vertical line

Claims (8)

A cleaning film having at least one pressure-sensitive adhesive layer on a support, wherein the pressure-sensitive adhesive layer contains at least one swellable gel. The cleaning film according to claim 1, wherein the pressure-sensitive adhesive layer contains 50 to 100 parts by mass of a swellable gel. The cleaning film according to claim 1, wherein the swellable gel is a hydrogel. The cleaning film according to claim 1, wherein the pressure-sensitive adhesive layer has a thickness before swelling of 0.05 μm to 10 μm. A cleaning method for cleaning a surface of a substrate having fine irregularities with a cleaning film, wherein the cleaning film uses the cleaning film according to any one of claims 1 to 4. . The cleaning method according to claim 5, wherein when the cleaning film is used, the cleaning film contains moisture in advance. The cleaning method according to claim 6, wherein the amount of water is 0.1 ml / g to 10.0 ml / g. The cleaning method according to claim 5, wherein the base material is a printed circuit board.

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