JP4814699B2 - Cleaning method of fluororesin film surface - Google Patents

Description

  The present invention relates to a method for cleaning the surface of a fluororesin film, and in particular, is particularly useful for cleaning a surface having a fluororesin that has been used for a long time and has undergone aged deterioration, and as a pretreatment for performing a treatment such as repair. The present invention relates to a method of cleaning the surface of a fluororesin film that is suitable for performing necessary cleaning on the spot with a fluororesin film attached to an existing structure.

Fluoropolymer processed products are characterized by “difficult to attach” and “not chemically react with other products”. A composite material coated with a fiber base fabric with a fluorine-containing resin (hereinafter referred to as “fluorine resin” as appropriate in this specification) having excellent oil and water repellency on the surface has high strength and stains on the surface. It is difficult to use and has excellent durability, so it is widely used as a roofing material for tents and dome-shaped structures.
The composite material having such a film made of a fluororesin (fluororesin film) has irregularities derived from the fiber base fabric on the surface, and when dirt adheres over time, it is difficult to remove it. In particular, when repair and repair are necessary due to deterioration over time, the surface is first cleaned, and further, surface treatment is performed to repair the material by adhering the repair material. There is a need for a method of cleaning the surface without causing degradation.

As a method of cleaning a composite material having a fluororesin film surface, after removing dirt adhering to the film surface using a resin brush, metal brush, etc., a method of spraying water containing a detergent at a high pressure, water Alternatively, there is a method of wiping with a cloth impregnated with a cleaning agent, and a physicochemical method of cleaning with a dry cloth after these cleaning treatments is generally performed.
However, according to such a physicochemical cleaning method, it has a great deal of labor compared to the cleaned state after cleaning, and in particular, if it is intended to completely remove the dirt on the concave portion of the concave and convex surface, the fluorine on the convex portion There is a concern that the resin film may be damaged, and the fluororesin film may be partially peeled off. Further, the surfactant used for cleaning remains on the film surface, which has a problem of adversely affecting the subsequent treatment.

As a method of cleaning the surface of the film without washing with water, for example, a paint is applied, and in the process that the paint dries to form a thin film, the contaminants on the surface of the film material are transferred to the thin film, and then the thin film is peeled off. Has proposed a method for removing contaminants on the surface of a film material (see, for example, Patent Document 1).
The thin film-forming paint used here is hard and fragile, so the thin film cannot be easily removed on the uneven film surface, and as a result, a physicochemical cleaning method such as water washing must be used together. There was a problem of not getting.
As a similar method, for example, as a method for cleaning a floor of a building, a cleaning method using a soft vinyl chloride film coated with a vinyl chloride resin solution and changed into a gel or solid state (see, for example, Patent Document 2). In addition, a method of applying an emulsion-based synthetic resin to a synthetic resin sheet or a synthetic resin plate, forming a film, and cleaning (for example, see Patent Document 3) has been proposed.

In these methods as well, the thin film present on the concave surface of the composite material having irregularities cannot be sufficiently removed, and in order to achieve sufficient cleaning, it is essential to use a cleaning means using liquid. In addition, because of the high water and oil repellency of the fluororesin film surface, it is difficult for liquid resin material to penetrate into the depths of the recesses and adhere to the surface. There is a region that is not formed in close contact with the surface of the fluororesin film, resulting in a problem that cleaning is insufficient.
Therefore, there is a demand for a method for efficiently cleaning a composite material having a fluororesin film surface, particularly an uneven surface.
JP-A-4-349984 JP-A-10-57918 JP 59-26177 A

  The object of the present invention made in consideration of the above problems is that the surface of the composite material having the fluororesin film surface can be cleaned by a simple method even when the surface has irregularities. An object of the present invention is to provide a method for cleaning the surface of a fluororesin film that can be sufficiently cleaned. In particular, an object of the present invention is to provide a method for cleaning a fluororesin film surface that can efficiently clean a composite material having a fluororesin film surface used in an existing structure on the site without damaging the film surface.

The problems of the present invention have been solved by the following means.
<1> Natural rubber, diene-based synthetic rubber, and diene-based film having a rubber elasticity on the surface of a composite material obtained by coating at least one surface of a fiber base fabric with a fluorine-containing resin. 1 or more types of rubber raw materials selected from the group consisting of copolymer synthetic rubber and an organic solvent having a static contact angle of 50 ° or less with respect to the surface of the fluororesin film, and a solid content concentration of 3 to 60% by mass the adhesive composition is applied is, dried, forming an adhesive layer in a predetermined area of the fluorine resin film surface, the pressure-sensitive adhesive layer, having no substrate extensibility Adhesive tape having an adhesive layer on the surface and having an adhesive strength measured by the method defined in JIS Z1524 (2004) of 2.15 N / 10 mm or more is adhered to the adhesive tape. A step of peeling the adhesive layer. Cleaning of the fluororesin film surface to.
<2> The fluorine-containing resin used in the composite material is a tetrafluoroethylene resin (PTFE), a tetrafluoroethylene perfluoroalkyl vinyl ether copolymer resin (PFA), or a tetrafluoroethylene-hexafluoropropylene copolymer. The method for cleaning a fluororesin film surface according to <1>, wherein the cleaning method is at least one selected from the group consisting of polymerized resins (FEP).

<3> The fiber base fabric used for the composite material has a fiber diameter of 3.30 μm to 4.05 μm, and includes at least one fiber selected from glass fiber, metal fiber, carbon fiber, and synthetic fiber. The method for cleaning a fluororesin film surface according to <1> or <2>, wherein the yarn is made of woven yarn.
<4>, wherein the coating amount of the adhesive composition in the step of forming the adhesive layer, either characterized <1> to the <3> to be a 100 to 300 g / ^{m 2} To clean the surface of the fluororesin film.
<5> The base material of the adhesive tape is selected from a paper base material, a paper base material having a resin coating layer, a cloth base material, a cloth base material having a resin coating layer, and a polyester resin sheet. <1> The cleaning method of the fluororesin film | membrane surface in any one of <4>.
<6> Any one of <1> to <5>, wherein drying in the step of forming the adhesive layer is performed by natural drying so that the surface of the adhesive layer is in a state of finger touch drying or more. The cleaning method of the fluororesin film | membrane surface of 1 item | term.

  According to the method of the present invention, the surface of a composite material having a fluororesin film surface can be cleaned by a simple method even when the surface has irregularities, and the surface can be sufficiently cleaned. A method for cleaning the surface of the fluororesin film can be provided. ADVANTAGE OF THE INVENTION According to this invention, there exists an outstanding effect that the composite material which has the fluororesin film | membrane surface used for the existing structure can be efficiently cleaned in the field, without damaging a film surface.

  The method for cleaning the surface of the fluororesin film of the present invention is to form a rubber-adhesive adhesive layer on the surface of the fluororesin coating, attach a contaminant to the adhesive layer, and then peel it off. Characteristically, with these configurations, contaminants can be sufficiently removed even at the bottom of the concave portion of the uneven surface, and the adhesive layer can be peeled off without any remaining film.

  The composite material to which the fluororesin film surface cleaning method of the present invention can be applied is not particularly limited as long as the fluororesin film is laminated on the surface of the fiber base fabric. A seed film formed by coating a base fabric with a fluororesin may be used. A type membrane is a membrane specified in the table of Ministry of Land, Infrastructure, Transport and Tourism, notification of membrane structure (2002 National Notification No. 666), second (structure of membrane surface), paragraph 2, item 1, standard As an example, the surface of a fiber base fabric woven with glass fiber yarns using monofilaments (fiber diameters of about 3.30 μm to 4.05 μm) conforming to the regulations of glass yarns, JIS R3413-1999 By coating with a coating agent selected from ethylene resin, tetrafluoroethylene perfluoroalkyl vinyl ether copolymer resin (PFA), tetrafluoroethylene-hexafluoropropylene copolymer resin (FEP), etc., the surface is a fluororesin A composite material having a film may be mentioned.

The composite material to which the method of the present invention can be applied is not limited to this and can be suitably applied to any material as long as the outermost surface of the fiber base fabric is coated with a fluororesin film. In particular, the effect of the present invention is remarkable when applied to the surface having irregularities derived from the fiber base fabric.
The fibers constituting the fiber base fabric are appropriately selected according to the purpose of use of the composite material, but usually require durability, so that inorganic fibers such as glass fibers, metal fibers, and carbon fibers, synthetic fibers, In particular, one or more kinds of fibers selected from high-strength organic synthetic fibers such as modified polyamide fibers represented by Kevlar fiber (trademark) are preferable, and a woven fabric formed by weaving yarns made of such fibers is used. be able to.
The thickness of the fiber is also selected according to the purpose, but generally it is preferably about 3.30 μm to 4.05 μm.
The fiber base fabric may be any of a woven fabric, a knitted fabric, and a non-woven fabric, but a woven fabric is preferable from the viewpoint of dimensional stability.

The fluororesin for coating the fiber base fabric is not particularly limited as long as it is a resin containing a fluoropolymer having a structural unit such as — (CF ₂ ) —. For example, tetrafluoroethylene resin (PTFE), 4 Examples thereof include a fluorinated ethylene perfluoroalkyl vinyl copolymer (PFA) and a tetrafluoroethylene-6 fluorinated propylene copolymer (FEP).
The surface of the composite material having such a fluororesin film on the surface may be smooth or uneven. However, the surface of the composite material is not suitable for the uneven surface, particularly the surface having fine unevenness caused by the fiber material. The method of the invention is particularly effective.

Hereinafter, the method of the present invention will be described in detail in the order of steps.
First, a step of forming a pressure-sensitive adhesive layer in a predetermined region on the surface of the fluororesin film is performed by applying and drying a pressure-sensitive adhesive composition having a rubber elasticity on the coated and dried film.
Prior to performing this process, a process such as attaching a masking tape around the area to be cleaned may be performed in order to partition the area to be cleaned.

The rubber elasticity in the present invention is a characteristic defined as “rubber-like elasticity” in the Chemical Dictionary (Kyoritsu Shuppan: 1960) Vol. 3, P699, that is, a reversible elastic region of strain is several hundred%, and an initial Young's modulus is 10 ⁶ to 10 ⁷ dyne / cm ² , temperature coefficient of Young's modulus is positive, stress-strain relationship does not follow Hook's law, and the film formed after coating and drying has the above characteristics Can be used as a rubber-elastic composition in the present invention.

<Adhesive composition>
As a material having a rubber elasticity in the coated and dried film, rubber or an elastomer material is contained as a main component of the adhesive, and the adhesive composition can further dissolve or disperse them uniformly. Contains solvent.
As rubber and elastomer used as the main component of adhesive, it has high solubility in the solvent described later, has rubber elasticity after film formation, and is not easily damaged by deformation. It is preferable to select a material having a certain degree of tackiness and not exhibiting strong adhesiveness. From such a viewpoint, for example, natural rubber (NR), Diene synthetic rubbers such as butadiene rubber (BR), isoprene rubber (IR), chloroprene rubber (CR), styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), butyl rubber, ethylene-propylene-dienemer and other dienes Rubber materials selected from non-diene synthetic rubbers such as acrylic copolymer rubber, styrene-butadiene Down - styrene block copolymer (SBS), styrene - ethylene - butadiene - is selected from thermoplastic elastomers such as styrene block copolymer (SEBS).

The adhesive composition of the present invention contains a solvent that can uniformly disperse or dissolve the adhesive main component. By selecting a solvent that has a small contact angle and good wetting with respect to the fluororesin, the adhesive composition penetrates into the fine recesses on the surface of the composite material and is contaminated on the surface. by involving the material during deposition, since that can achieve excellent stain removability, relative to the fluorine resin film surface used, select those than 50 ° as static contact angle. Here, the measurement of a contact angle can be performed using the contact angle measuring device goniometer G-1 available from Elma Sales Co., Ltd. The measurement method is to apply the organic solvent to be measured to the PTFE resin coating as the fluororesin coating by the small droplet method, and the measurement method includes the θ / 2 method and the hr method using a micrometer. Use.

Usable solvents selected from such a viewpoint include toluene, xylene, hexane, heptane, hexadecane, industrial gasoline, etc. Among them, toluene (room temperature) is preferred from the viewpoint of affinity for the PTFE resin membrane surface. Preferred examples include a static contact angle with respect to the surface of the PTFE resin film of 42 °), xylene (same as 48 °), and hexane (same as 10 ° or less), and these may be used alone or mixed as necessary. A solvent can be used.
The contents of the main component of the adhesive and the organic solvent in the adhesive composition can be appropriately adjusted depending on the arrangement state of the composite material to which the adhesive is applied, the state of dirt, etc. From the viewpoint, the solid content concentration of the adhesive is required to be 3 to 60% by mass, and more preferably in the range of 10 to 20% by mass.

Although there is no restriction | limiting in particular in the application quantity of an adhesive composition, 100-300 g / m < ² > is suitable for the application quantity at the time of using an adhesive main ingredient density | concentration 10-20%, 100 to 200 g / m ² is more preferable, but both the formed rubber-elastic film and the organic solvent are removed after the operation, so that the effects of the invention are not impaired even when used outside this range. .
The application can be performed by a conventional method, and a method such as application with a brush or roller application can be employed according to the working environment.
Drying after application may be performed by any method such as natural drying, heat drying with hot air or a non-contact type heater, but from the viewpoint of energy saving. Natural drying is preferable, and when working outdoors, it is preferable to dry for 5 to 10 minutes or more in summer and 15 to 30 minutes or more in winter. It is preferable that the drying is performed so as to be in a state of not less than finger touch drying.
In this way, an adhesive layer is formed in a predetermined region on the surface of the fluororesin film.

Next, a step of sticking a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer on the surface of the base material to the pressure-sensitive adhesive layer formed in the previous step, and peeling the pressure-sensitive adhesive layer by the pressure-sensitive adhesive force of the pressure-sensitive adhesive tape. carry out.
By this peeling step, contaminants that have migrated to the adhesive layer due to surface tackiness during film formation of the adhesive layer are peeled off together with the adhesive layer, and the cleaning of the fluororesin film surface is achieved. .
Here, when the adhesive layer is peeled off, the adhesive layer coating has rubber elasticity, so it is flexible and stretchable. Concerned. For this reason, an adhesive tape having an adhesive layer on the surface of a substrate that does not have extensibility is used for peeling.
The pressure-sensitive adhesive tape used here has an adhesive force between the pressure-sensitive adhesive layer and a rubber-adhesive adhesive layer (coating) formed on the surface to be cleaned. Any material can be used as long as it has a larger adhesive strength with the surface.

As the base material of the adhesive tape, any sheet may be used as long as it is a flexible and non-extensible sheet. For example, a paper base, a paper base having a resin coating layer, a cloth base (base cloth) ), A resin base material having a resin coating layer, a resin sheet selected from a polyester resin typified by polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PTE).
As long as it has the adhesive force prescribed | regulated below, what kind of thing may be sufficient as an adhesive.
As the adhesive tape used in the present invention, commercially available kraft tape, gum tape, and the like can also be used. As the adhesive strength, the adhesive strength specified in JIS Z1524 (2004) packaging adhesive tape for packaging, that is, 2 Any one having an adhesive strength of 15 N / 10 mm or more can be preferably used.

In this step, the adhesive tape was adhered to the adhesive tape after the adhesive tape was adhered to the formed rubber-adhesive adhesive layer with sufficient rubber elasticity, and after the adhesive tape was peeled off. The layer is peeled from the surface of the fluororesin film. Since the adhesive tape has a non-stretchable base material, the adhesive layer can be peeled off without fear of damage due to stretching, and the adhesive layer formed in fine recesses can also be removed without concern for residual film become. At this time, the contaminants transferred to the surface of the fluororesin film when the adhesive layer is formed are also removed at the same time.
The presence or absence of the residual film of the adhesive layer and the removal state of contaminants are confirmed visually or by observation with a magnifying glass.

According to this method, the adhesive composition is applied in a liquid form to form an elastic film, and the peeling is performed with the adhesive tape having the base material. Contaminants on the resin film surface can be effectively removed.
In this way, it is possible to efficiently clean the composite material having the fluororesin film surface used in existing buildings and the like. Since there are no impurities or contaminants on the surface of the cleaned fluororesin film, a process for applying an adhesive and bonding it to another material such as a restoration material, or a paint, is performed as desired. And various processes such as a step of applying a design by adding a colorant and a surface adhesion improving treatment as a pretreatment thereof can be easily performed.

  The method for cleaning the surface of the fluororesin film of the present invention is used in existing buildings and the like because it is performed in a simple process of applying a liquid composition to the surface to be cleaned and peeling it off with an adhesive tape after film formation. Even a composite material that has a fluororesin film that has surface irregularities can be easily applied on site, and is a non-rigid material, such as a dome or tent covering material, that is, a small rigidity, Even for a fluororesin film surface whose shape is changed by an external force, it can be easily cleaned without damaging the film surface, so that its application range is wide.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.
Example 1
As a composite material having a fluororesin film surface, a seed A film (manufactured by Saint-Gobain-SFII: surface fluororesin: PTFE) was used. This type A film was prepared as a new, deteriorated level for outdoor exposure for 1 year and outdoor exposure for 20 years, and used as a composite material to which contaminants adhered.
Adhesive composition: Neo Bond R (composition of chloroprene rubber dissolved in toluene / industrial gasoline = 7/3 solvent, solid content concentration: 15% by mass) 150 g / m ² applied. It was naturally dried at room temperature and confirmed to be in a dry-to-touch state that does not adhere even when touched with a finger. The drying time was 15 minutes. In this way, an adhesive layer was formed on the surface of the seed A film.
After that, an adhesive tape (made by Sekisui Chemical Co., Ltd., cloth tape No. 600V, adhesive strength: 3.40 N / 10 mm) is adhered to the surface of the formed adhesive layer, and after adhering sufficiently, the adhesive is applied. When the tape was peeled off, the adhesive layer coating adhered to the adhesive layer of the adhesive tape was also peeled from the surface of the seed A film at the same time.
The surface after peeling was observed with a loupe and evaluated according to the following criteria. The results are shown in Table 1 below.

(Dirt removal)
A: There is no pollutant that can be confirmed by loupe observation.
○: There is almost no pollutant that can be confirmed by loupe observation.
X: The contaminant which can be confirmed by magnifying glass observation was observed by the recessed part of the surface.
XX: Contaminants that can be confirmed by loupe observation were observed over the entire surface.
(Residual film of adhesive layer)
○: No residual film of the adhesive layer was observed.
X: A residual film of the adhesive layer was observed.

(Example 2)
The adhesive composition used in Example 1 was manufactured by Mitsuboshi Belting Co., Ltd., NeoPrimer TF (modified polyisobutylene rubber dissolved in n-heptane / n-hexane = 8/2 mixed solvent, solid content concentration : The surface of the seed A film was cleaned in the same manner as in Example 1 except that the amount was changed to 15% by mass) and evaluated in the same manner. The results are shown in Table 1 below.
(Comparative Example 1)
The adhesive composition used in Example 1 is a commercially available vinyl chloride resin adhesive: manufactured by Mitsubishi Resin Chemical Co., Ltd., Hishibond HI (composition in which vinyl chloride resin is dissolved in tetrahydrofuran, solid content concentration: about 15 The surface of the seed A film was cleaned and evaluated in the same manner as in Example 1 except that the coating amount was changed to 180 g / m ² instead of (mass%). The drying time of the film was 20 minutes, and the formed film was a film having no rubber elasticity. The results are shown in Table 1 below.

(Comparative Example 2)
The adhesive composition used in Example 1 is a commercially available urethane paint: manufactured by Kansai Paint Co., Ltd., Arestane (a composition in which a polyurethane resin is dissolved in a mixed solvent of xylene / ethylbenzene = 1/1, solid The surface of the seed A film was cleaned and evaluated in the same manner as in Example 1 except that the coating amount was changed to 180 g / m ² instead of the concentration of 15.2% by mass. The drying time of the film was 20 minutes, and the formed film was a film having no rubber elasticity. The results are shown in Table 1 below.
(Comparative Example 3)
The adhesive composition used in Example 1 is a commercially available emulsion paint: manufactured by Kansai Paint Co., Ltd., Vine Deluxe Sharp (a dispersion in which acrylic resin particles are uniformly dispersed in water, solid content concentration: 15 mass) The surface of the seed A film was cleaned and evaluated in the same manner as in Example 1 except that it was replaced with%). The surface of the seed A film was cleaned and evaluated in the same manner as in Example 1 except that the coating amount was 180 g / m ² . The drying time of the film was 360 minutes, and the formed film was a film having no rubber elasticity. The results are shown in Table 1 below.

As shown in Table 1, after applying the adhesive material solution having rubber elasticity to the surface to be cleaned of the seed A film, and forming and drying the film, the film was peeled off with a tape with an adhesive. In this case, the surface was well soiled and no residual film of the adhesive layer was observed.
On the other hand, even if a resin-based film-forming material is used, the method of Comparative Examples 1 and 2 in which the formed film does not have rubber elasticity can remove dirt to some extent, but it penetrates into fine irregularities on the seed A film surface. The dried resin film could not be removed and remained, and the surface was not sufficiently cleaned. Further, in Comparative Example 3 using a water-based emulsion material, it takes time to dry and form the film, and the emulsion-based composition does not sufficiently adhere to the surface of the water-repellent fluororesin film. It can be seen that it cannot be removed sufficiently, and in particular, dirt remains in the recesses on the surface. Further, when a new product having a high surface water repellency was used, the remaining resin film was also observed.

  As described above, according to the present invention, it is possible to very efficiently remove dirt substances including uneven surfaces without damaging the membrane surface, and thus, for example, safety under extremely unstable conditions such as on a membrane roof. It can be seen that cleaning can be performed and the surface of the fluororesin film such as the A-type film surface can be repaired, the welding method as a repair method, and the bonding method can be greatly contributed to ensuring the quality.

Claims (6)

Natural rubber, diene-based synthetic rubber, and diene-based copolymer synthetic rubber whose coated and dried film has rubber elasticity on the surface of a composite fluororesin film formed by coating at least one side of a fiber base fabric with a fluorine-containing resin. And one or more rubber raw materials selected from the group consisting of thermoplastic elastomers and an organic solvent having a static contact angle of 50 ° or less with respect to the surface of the fluororesin film, and a solid content concentration of 3 to 60 mass % Adhesive coating composition, and drying to form a pressure-sensitive adhesive layer in a predetermined area of the fluororesin film surface, and a non- extensible group in the pressure-sensitive adhesive layer. Adhesive layer having a pressure-sensitive adhesive layer on the surface of the material and having an adhesive strength measured by the method defined in JIS Z1524 (2004) of 2.15 N / 10 mm or more , Removing the adhesive layer. A method for cleaning the surface of a fluororesin film.   The fluorine-containing resin used for the composite material is tetrafluoroethylene resin (PTFE), tetrafluoroethylene perfluoroalkyl vinyl ether copolymer resin (PFA), and tetrafluoroethylene-hexafluoropropylene copolymer resin ( The method for cleaning a surface of a fluororesin film according to claim 1, wherein the cleaning method is at least one selected from the group consisting of FEP).   The fiber base fabric used for the composite material has a fiber diameter of 3.30 μm to 4.05 μm, and is formed of one or more kinds of fibers selected from glass fiber, metal fiber, carbon fiber, and synthetic fiber. 3. The method for cleaning a surface of a fluororesin film according to claim 1 or 2, wherein the method is a woven material. 4. The application amount of the adhesive composition in the step of forming the adhesive layer is 100 to 300 g / m ² , wherein the adhesive amount is 100 to 300 g / m ² . Cleaning method for fluororesin film surface. The base material of the adhesive tape is selected from a paper base material, a paper base material having a resin coating layer, a cloth base material, a cloth base material having a resin coating layer, and a polyester resin sheet. The cleaning method of the fluororesin film | membrane surface of any one of thru | or 4 thru | or 4. The drying in the step of forming the adhesive layer is performed by natural drying so that the surface of the adhesive layer is in a state of finger touch drying or more. The cleaning method of the fluororesin film | membrane surface of description.