JP2008019393A - Surface coated fluororesin substrate and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluororesin substrate having a graft polymer layer having a good surface appearance on its surface, wherein an amount of an acrylic resin homopolymer is remarkably small. <P>SOLUTION: A method of producing the surface-coated fluororesin substrate comprises effecting the gas phase polymerization on a fluororesin substrate by a vapor plasma of an acrylic type monomer under atmospheric pressure in a plasma atmosphere of an inert gas by corona discharge, to thereby form an acrylic resin layer being graft-polymerized with the surface of the above fluororesin substrate. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a surface-coated fluororesin substrate and a method for producing the same. More specifically, the present invention relates to a surface-coated fluororesin substrate having a fluororesin substrate, a surface of the fluororesin substrate and a graft-polymerized acrylic resin layer, and a method for producing the same.

  The fluororesin substrate has low water vapor and oxygen permeability. Therefore, the use of a fluororesin substrate has the advantage that the deterioration of organic dyes used in image display devices such as electronic paper can be prevented. Further, since the fluororesin substrate has a low dielectric constant and excellent high frequency characteristics, when used as a flexible substrate, there is an advantage that a thin flexible wiring substrate can be obtained as compared with a conventional polyimide substrate.

In a substrate for an image display device, a flexible substrate, etc., it is usually necessary to laminate another component member (for example, wiring, interlayer insulating film) on the substrate, but the fluororesin substrate has poor surface wettability. For this reason, other laminated components may be easily peeled off.
By the way, a method for improving surface characteristics by treating the surface of a resin substrate by corona discharge has been known for a long time. However, this method has a problem that the effect of the modification cannot be maintained for a long time, and particularly in the case of a fluororesin substrate, the effect maintaining time is extremely short.

In view of this, a method has been proposed in which the surface of the fluororesin substrate is treated by a low-pressure plasma method in an inert gas atmosphere such as He, and then an acrylic resin graft polymerization layer is formed on the treated surface (Japanese Patent Laid-Open No. Hei 7). -164600 gazette: Patent Document 1). Specifically, a fluororesin substrate such as PTFE (polytetrafluoroethylene: trade name Teflon (registered trademark)) or FEP (perfluoroethylene propylene copolymer) is treated by glow discharge of He gas under low pressure, and after treatment The surface-coated fluororesin substrate is obtained by immersing the substrate in a monomer solution corresponding to the acrylic resin to form a monomer layer, and heating the monomer layer to form a graft polymerization layer.
JP 7-164600 A

In the above publication, a method comprising a plasma treatment step under a low pressure, a step of immersing the substrate in a monomer solution, and a step of heating the monomer layer is described as a method for forming the graft polymerization layer. The graft polymerization layer obtained by such a method may include not only the graft polymer but also a homopolymer of an acrylic resin due to the monomer solution adhering to the substrate more than necessary during immersion. there were. When such a homopolymer is included in the graft polymerization layer, there is a problem that the adhesive strength of the graft polymerization layer is lowered, and there is a problem that the surface state of the graft polymerization layer becomes poor. The latter problem has been a cause of poor conduction and insulation failure when another component (for example, wiring, interlayer insulating film) is further laminated on the graft polymerization layer.
Furthermore, in the above publication, since a low-pressure plasma treatment process, an immersion process, and a heating process are required to form the graft polymerization layer, it is also desired to shorten the formation time.

In view of the above problems, the inventors of the present invention, as a result of intensive studies, have simultaneously performed corona discharge treatment and graft polymerization under atmospheric pressure, so that there is very little homopolymer of acrylic resin and the surface state of Surprisingly, it has been found that a fluororesin substrate having a good graft polymerization layer on its surface can be obtained, leading to the present invention.
Thus, according to the present invention, gas phase polymerization is caused by vapor plasma of an acrylic monomer on a fluororesin substrate under an inert gas plasma atmosphere and atmospheric pressure by corona discharge, and graft polymerization is performed on the surface of the fluororesin substrate. There is provided a method for producing a surface-coated fluororesin substrate characterized by obtaining an acrylic resin layer.

  Furthermore, according to the present invention, there is provided a surface-coated fluororesin substrate obtained by the above production method, comprising a fluororesin substrate, and a surface of the fluororesin substrate and a graft-polymerized acrylic resin layer. The

According to the method of the present invention, it is possible to obtain a surface-coated fluororesin substrate having on its surface a graft polymer layer having an extremely small amount of an acrylic resin homopolymer and a good surface state.
The surface-coated fluororesin substrate of the present invention has a high adhesive strength of the graft polymerization layer. In addition, since the surface state is good, there is an advantage that even if another layer is laminated on the graft polymerization layer, defects such as cracks are hardly generated in the other layer.

  In the method of the present invention, the graft polymerization of the surface of the fluororesin substrate and the acrylic monomer is performed by gas phase polymerization in a plasma atmosphere of an inert gas by corona discharge and at atmospheric pressure. The inventors presume that graft polymerization is performed as follows in the present invention.

That is, as described in the above publication, conventionally, the surface of a fluororesin substrate is plasma-treated to generate radicals on the surface of the substrate. When the acrylic monomer comes into contact with the generated radical, the acrylic monomer is graft-polymerized on the fluororesin substrate to form an acrylic resin layer.
On the other hand, in the present invention, since both the surface of the fluororesin substrate and the acrylic monomer are placed in an inert gas plasma atmosphere by corona discharge, radicals are generated on the substrate surface, and the acrylic monomer becomes vapor plasma. The generated radicals and vapor plasma preferentially cause graft polymerization, and as a result, an acrylic resin layer is formed. In the method of the present invention, monomer vapor plasma is used as compared with the conventional method, so that self-polymerization of the monomer can be further suppressed.

  By the way, in the above publication, it is said that homopolymerization of the monomer is inevitable when plasma treatment is performed in the coexistence of the substrate and the monomer, but since this publication forms a monomer layer on the substrate by immersion, Alternatively, the inventors presume that this is because the resin layer is formed after the plasma treatment. On the other hand, in the present invention, since an acrylic resin layer is formed from a monomer at once in a plasma atmosphere by corona discharge by a vapor phase method, it is necessary to form a monomer layer or to form a resin layer again after discharge treatment. Therefore, homopolymerization can be suppressed from the above publication.

The fluororesin substrate that can be used in the present invention is not particularly limited, and any known substrate can be used. Specifically, ethylene-tetrafluoroethylene copolymer (ETFE), polyvinyl fluoride resin (PVF), tetrafluoroethylene-perfluoroether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer ( Examples thereof include a base made of FEP), polytetrafluoroethylene (PTFE), vinylidene fluoride resin (PVdF), trifluorochloroethylene resin (PCTFE), ethylene-trifluorochloroethylene copolymer resin (ECTFE), or the like. The fluororesin substrate may contain additives such as pigments, fillers, and lubricants.
The fluororesin substrate may have a planar structure such as a film, a sheet, or a panel, or may have a three-dimensional structure having tubes, pipes, and irregularities.

  Next, the acrylic monomer is not particularly limited, and any known monomer can be used. Specifically, methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, tridecyl acrylate, stearyl acrylate, cyclohexyl acrylate, acrylic Propyl acrylate, benzyl acrylate, isopropyl acrylate, sec-butyl acrylate, acrylic acid, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, glycidyl acrylate, acrylic Tetrahydrofurfuryl acid, allyl acrylate, ethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, 1,3-butyric diacrylate Glycol, trimethylolpropane triacrylate, 2-ethoxyethyl acrylate, ethoxyethoxyethyl acrylate, 2-methoxyethyl acrylate, phenoxyethyl acrylate, phenoxypolyethylene glycol acrylate, dimethylaminoethylmethyl chloride acrylate, etc. Acrylic acid derivatives of

Methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, tridecyl methacrylate, stearyl methacrylate, cyclohexyl methacrylate, propyl methacrylate, methacrylic acid Benzyl, isopropyl methacrylate, sec-butyl methacrylate, methacrylic acid, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, glycidyl methacrylate, tetrahydrofurfuryl methacrylate, Allyl methacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethyl dimethacrylate Glycol, 1,3-butylene glycol dimethacrylate, trimethylolpropane trimethacrylate, 2-ethoxyethyl methacrylate, ethoxyethoxyethyl methacrylate, 2-methoxyethyl methacrylate, phenoxyethyl methacrylate, phenoxypolyethylene glycol methacrylate, Examples include methacrylic acid derivatives such as dimethylaminoethyl methyl chloride methacrylate.
Of the acrylic monomers, acrylic acid is preferred.

Next, the acrylic monomer is vapor-phase polymerized on the fluororesin substrate. This gas phase polymerization is performed in a plasma atmosphere of an inert gas by corona discharge and under atmospheric pressure. By this gas phase polymerization, the surface of the fluororesin substrate and the acrylic monomer are graft-polymerized, and an acrylic resin layer as a graft polymerization layer is obtained on the fluororesin substrate.
The inert gas means a gas that is not reactive with a fluororesin substrate or an acrylic monomer. Examples of such a gas include noble gases such as helium and argon, nitrogen gas, and air. Here, since oxygen has a function of deactivating radicals, it is preferable that oxygen be as small as possible. Therefore, it is more preferable to use rare gas or nitrogen gas.

Corona discharge is performed under atmospheric pressure. In the present invention, under atmospheric pressure does not mean strictly 1 atmosphere (1013 hPa), but may be pressurized or reduced in the range of 500 to 2000 hPa as necessary. If pressure is applied, it is possible to prevent an unintended gas (for example, oxygen in the air) from flowing into the plasma atmosphere. Pressurization is particularly useful when gas phase polymerization is carried out continuously and in an open system.
The corona discharge conditions are not particularly limited as long as an inert gas plasma atmosphere and monomer vapor plasma can be formed. Specifically, the frequency of an applied voltage of 1 kHz to 100 kHz is applied to a pair of corona discharge electrodes (corona discharge electrode unit, head), although it varies slightly depending on the type of inert gas used and the configuration of the corona discharge device. It is preferable to apply a voltage having a discharge voltage of 1 kV to 20 kV, a pulse modulation frequency of 10 Hz to 200 Hz, and a pulse duty of 10% to 90%. Note that, for example, two heads can be corona discharged with a single power supply device.

When the frequency is lower than 1 kHz, the temperature of the plasma becomes high, and there is a possibility that the workpiece is thermally damaged. On the other hand, when the frequency is higher than 100 kHz, the processing time may be long because the plasma density is low.
Further, when the discharge voltage is lower than 1 kV, the discharge becomes unstable and may stop.
On the other hand, when the voltage is higher than 20 kV, the discharge becomes strong and arc discharge occurs, resulting in high-temperature plasma, which may cause thermal damage to the processed material.

When the pulse modulation frequency is lower than 10 Hz, there is a possibility that the discharge becomes intermittent and the processing time becomes long. On the other hand, when the frequency is higher than 200 Hz, the processing area may be reduced because the plasma flare blown from the head is shortened.
Further, when the pulse duty is lower than 10%, the plasma density may be lowered and the plasma flare may be shortened. On the other hand, if it is higher than 90%, the plasma temperature may be high.

More preferable frequency, discharge voltage, pulse modulation frequency and pulse duty are 10 kHz to 50 kHz, 5 kV to 15 kV, 30 Hz to 100 Hz, 30% to 70%.
The temperature of the polymerization system during corona discharge is usually room temperature (about 25 ° C.). However, the polymerization system may be heated and cooled depending on the type of acrylic monomer used. For example, when using a monomer having a high boiling point, it is preferable to maintain the gas phase by heating. Moreover, it is preferable to perform corona discharge until the acrylic resin layer of desired thickness is obtained. Specifically, it is preferably performed for 10 to 100 seconds. If the polymerization is carried out for too long, the amount of the homopolymer of the acrylic monomer increases, which is not preferable.

Moreover, the plasma atmosphere of an inert gas can be formed by flowing an inert gas directly or indirectly to the place where corona discharge is performed. Here, the flow rate of the inert gas is preferably 10 to 100 L / min, though it depends on the corona discharge conditions.
On the other hand, the acrylic monomer may flow directly or indirectly to the place where corona discharge is performed, as in the case of the inert gas, and a container for holding the acrylic monomer with a heater in the corona discharge device. The acrylic monomer may be evaporated and supplied by installing and heating the container.

In the latter supply method, for example, the acrylic monomer solution is evaporated by using a manufacturing apparatus provided with a corona discharge device, a fluororesin base, and an open container holding the acrylic monomer solution in the same container. Thus, vapor plasma derived from the acrylic monomer supplied can be supplied. An example of an apparatus that can be used for the latter supply method is shown in FIG.
An example of an apparatus that can be used in the manufacturing method of the present invention is shown in FIG. The apparatus shown in FIG. 1 includes a discharge plasma irradiation apparatus 2 that irradiates a substrate 1 with discharge plasma and a graft treatment tank 3 that polymerizes an acrylic monomer.

  The discharge plasma irradiation apparatus 2 includes an apparatus main body 4 equipped with an AC power source, a transformer, and the like, a discharge unit (head) 5 connected to the apparatus main body 4, and a gas supply mechanism 6 for supplying a discharge gas to the discharge unit (head). It has. Any commercially available apparatus can be used for the discharge plasma irradiation apparatus 2, and among them, Plasmastream PSC1002 manufactured by Pearl Industry Co., Ltd. can be preferably used.

  A gas outlet 8 is opened in the lower end surface 7 of the discharge unit (head) 5, and a pair of electrodes 9 are symmetrically arranged on both sides of the gas outlet. A gas cylinder 10 is connected to the discharge unit (head) 5 via a flow meter and a flow rate control function so that an inert gas can be supplied in a constant amount. When a pulse voltage is applied to the pair of electrodes 9, corona discharge occurs between the electrodes. The discharge plasma generated by the corona discharge is sprayed downward from the lower end surface 7 of the discharge unit (head) together with the jet gas jetted from the gas jet port 8 so that the discharge plasma can be irradiated.

  The graft processing tank 3 is a substantially sealed box-shaped container, and has a storage tank 13 for an acrylic monomer 12 provided with a heater 11 and a support mechanism 14 for supporting the substrate 1. A discharge unit (head) 5 is disposed on the upper side in the graft processing tank 3, and a storage tank 13 is disposed on the lower side. The support mechanism 14 is configured so that the substrate 1 can be moved up and down from the vicinity of the lower end surface 7 of the discharge unit (head) over the storage tank 13. In FIG. 1, a plate 15 for installing a base is disposed between the discharge unit (head) 5 and the storage tank 13. A pair of arms 16 whose upper portions protrude outward from the upper wall surface of the graft processing tank 3 are attached to both sides of the plate 15. The discharge plasma irradiation position generated near the lower end surface 7 of the discharge unit (head) can be adjusted by operating the arm 16 up and down. In FIG. 1, 17 is an exhaust port.

  A method of forming an acrylic resin layer on the substrate 1 will be described using the apparatus shown in FIG. First, the storage tank 13 is filled with the acrylic monomer 12, and the substrate 1 is placed on the plate 15 at the discharge plasma irradiation position. Next, in a state where the jet gas is jetted, it is applied to the electrode 9 to cause corona discharge. Next, the storage tank 13 is heated by the heater 11 to evaporate the acrylic monomer, thereby diffusing the acrylic monomer in the graft treatment tank 3. In this state, the surface 1b of the substrate 1 is irradiated with discharge plasma to form vapor plasma of the acrylic monomer and radicals on the substrate 1, whereby the acrylic monomer is polymerized on the substrate 1, and the acrylic resin layer is formed. It is formed.

The surface-coated fluororesin substrate obtained by the method of the present invention has a very good surface condition because the acrylic resin layer on the surface has few homopolymers of acrylic monomers. Moreover, since there are few homopolymers, the adhesiveness of the acrylic resin layer itself to the substrate is very good.
Further, the thickness of the acrylic resin layer is not particularly limited, but is preferably 10 μm or less from the viewpoint of suppressing the generation of a homopolymer. A more preferable thickness is 0.01 μm to 1 μm.

  Furthermore, since the surface-coated fluororesin substrate has the above-mentioned good properties, even if another thin film such as a wiring or an interlayer insulating film is formed on the acrylic resin layer, the other thin film has a defect such as a crack. Is unlikely to occur. Therefore, the surface-coated fluororesin substrate of the present invention can be suitably used as a material for electronic components such as flexible image display devices and flexible wiring boards.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.
Example 1
A surface-coated fluororesin substrate was manufactured using the apparatus shown in FIG. As the discharge plasma irradiation apparatus 2, Plasmastream PSC1002 manufactured by Pearl Industry Co., Ltd. was used. A pair of electrodes 9 in the discharge plasma irradiation apparatus 2 are 2 mmφ tungsten rods, and have the same outer shape (length 5 cm, mounting interval 3 cm, tip discharge part bent in a letter shape). The interval was set to 0.5 to 3 cm.

A fluororesin film (Teflon (registered trademark) manufactured by Deyupon Co., Ltd .; PFA; length 15 cm, width 10 cm, thickness 0.1 mm) as the substrate 1 was placed on the plate 15 in the support mechanism 14. Next, the fluororesin film was fixed so that the distance between the upper surface of the fluororesin film and the lower end surface 7 of the discharge unit (head) was about 10 mm.
The storage tank 13 provided with the heater 11 was filled with acrylic acid monomer (special grade manufactured by Wako Pure Chemical Industries, Ltd .; 100% stock solution) and heated to 45 ° C. to generate acrylic monomer vapor.
Next, the graft treatment tank 3 was purged by flowing Ar gas into the discharge unit 5 at an atmospheric pressure (about 1013 hPa) at a flow rate of 10 L / min for about 15 minutes and exhausting from the exhaust port 17.

  Next, a high voltage (about 12 kV) of high frequency (20 kHz) is applied to the pair of electrodes 9 while flowing Ar gas at a flow rate of 100 L / min, thereby generating corona discharge in a vapor atmosphere of Ar gas and acrylic acid. I let you. As discharge conditions other than the above, the pulse modulation frequency was 60 Hz, and the pulse duty was 50%. Under this corona discharge, the fluororesin film was exposed for 75 seconds. As a result, a fluororesin film whose surface was coated with a polyacrylic acid resin layer was obtained. The SEM photograph of the surface of the obtained film is shown in FIG. 2 (2000 times). A SEM photograph of the surface of the untreated film before coating with the resin layer is shown in FIG. 3 (2000 times). The SEM photograph was taken using an E-SEM-2700 manufactured by Nikon Corporation with an acceleration voltage of 15 kV.

Comparative Example 1
In the same manner as in Example 1, the fluororesin film was fixed, and the grafting tank was purged.
Subsequently, a corona discharge was generated in an Ar gas atmosphere by applying a high frequency high voltage to the pair of electrodes 9 in the same manner as in Example 1 without heating the storage tank 13. Under this corona discharge, the fluororesin film was exposed for 75 seconds.

Thereafter, the fluororesin film was immediately immersed in an acrylic acid monomer solution (special grade manufactured by Wako Pure Chemical Industries, Ltd .; 100% stock solution) together with the support mechanism 14 and subjected to a graft polymerization treatment for 30 minutes. The flow rate of Ar gas during the polymerization process was set to 10 L / min. As a result, a fluororesin film whose surface was coated with a polyacrylic acid resin layer was obtained. The SEM photograph of the surface of the obtained film is shown in FIG. 4 (2000 times).

Comparative Example 2
A fluororesin film whose surface was coated with a resin layer of polyacrylic acid was obtained in the same manner as in Comparative Example 1 except that the acrylic acid monomer solution was replaced with a 50 vol% aqueous solution of acrylic acid monomer.

The films obtained in Example 1 and Comparative Examples 1 and 2 were washed with pure water, dried, and subjected to contact angle measurement, peel test, and elemental analysis as follows.

(Contact angle measurement)
The contact angles of the films of Example 1 and Comparative Examples 1 and 2 were measured. Further, the contact angle of PFA before treatment was also measured. For the measurement of the contact angle, an automatic solid surface energy analyzer CA-VE type manufactured by Kyowa Interface Science Co., Ltd. was used. After the landing, a 1000 msec water droplet was measured and analyzed by the θ / 2 method.
In addition, wettability is so high that a contact angle is small, and it means that the other layer formed on a film is hard to peel.

(Peel test)
The peel test (T type) of Example 1 and Comparative Examples 1 and 2 was performed. Moreover, the peeling test of the PFA film before a process was also performed.
The peel test was performed as follows. That is, the length of a film cut out to a width of 25 mm and a length of 100 mm on an Al plate coated with an epoxy adhesive (E-set manufactured by Konishi Co., Ltd.) with a baker-type applicator (manufactured by Tester Sangyo Co., Ltd.) at a thickness of 250 μm. The 50 mm portion was bonded, and the adhesive was cured by allowing it to stand at room temperature (about 25 ° C.) for 24 hours while applying a 5N load. Thereafter, the Al plate was peeled off at a rate of 100 mm / min, and the tensile strength at that time was measured by an autograph AG-10kNG manufactured by Shimadzu Corporation.

(Elemental analysis)
Elemental analysis of the films of Example 1 and Comparative Examples 1 and 2 was performed by ESCA method using ESCA-3300 manufactured by Kratos. The measurement was performed under the conditions of an X-ray source of MgKα (1253.3 eV), an excitation voltage of 8 kV, and a current current of 30 mA.

The results of contact angle measurement, peel test, and elemental analysis are shown in Tables 1 to 3, respectively.

Table 1 shows the following.
From Example 1 and Comparative Examples 1 and 2, the contact angle of the obtained surface-coated fluororesin film is remarkably lowered by subjecting the acrylic acid monomer to gas phase polymerization in a corona discharge atmosphere. Therefore, when another layer is laminated | stacked on this film, the adhesiveness of another layer and a film can be improved. This improvement is supported by Table 2 below.

Table 2 shows the following.
From Example 1 and Comparative Examples 1 and 2, the tensile strength of the obtained surface-coated fluororesin film can be significantly increased by vapor-phase polymerization of the acrylic acid monomer in a corona discharge atmosphere. Therefore, when another layer is laminated | stacked on this film, the adhesiveness of another layer can be improved.

Table 3 shows the following.
Compared to the untreated film, the oxygen component increases and the fluorine component decreases. Therefore, it can be seen that a polyacrylic acid resin layer is formed on the film.

Moreover, according to the SEM photograph of FIGS.
From FIG. 3 which is an unprocessed SEM photograph and FIG. 4 of Comparative Example 1, it can be seen that the film of Comparative Example 1 has irregularities formed on the surface. This unevenness is formed from a homopolymer of acrylic acid monomer, and it is estimated from Tables 1 and 2 that the homopolymer deteriorates the contact angle and tensile strength. On the other hand, no irregularities can be confirmed in FIG. Therefore, it is estimated that there are very few homopolymers and most acrylic acid monomers are graft-polymerized on the film.

It is the schematic of the apparatus which can be used for manufacture of the surface covering fluororesin base | substrate of this invention. 2 is a SEM photograph of the film obtained in Example 1. It is a SEM photograph of a PFA film. 2 is a SEM photograph of the film obtained in Comparative Example 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base | substrate 2 Discharge plasma irradiation apparatus 3 Graft processing tank 4 Apparatus main body 5 Discharge unit (head)
6 Gas supply mechanism 7 Lower end surface 8 Gas outlet 9 Electrode 10 Gas cylinder 11 Heater 12 Acrylic monomer 13 Storage tank 14 Support mechanism 15 Plate 16 Arm 17 Exhaust port

Claims (5)

  In the plasma atmosphere of the inert gas by corona discharge and atmospheric pressure, vapor phase polymerization is caused by vapor plasma of acrylic monomer on the fluororesin substrate to obtain an acrylic resin layer graft-polymerized with the surface of the fluororesin substrate. A method for producing a surface-coated fluororesin substrate characterized by the above.   The vapor plasma is supplied by evaporating the acrylic monomer solution using a manufacturing apparatus equipped with a corona discharge device, a fluororesin substrate, and an open container holding the acrylic monomer solution in the same container. The method for producing a surface-coated fluororesin substrate according to claim 1, wherein the method is derived from an acrylic monomer.   The corona discharge is applied to a corona discharge electrode at a frequency of an applied voltage of 1 kHz to 100 kHz, a discharge voltage of 1 kV to 20 kV, a pulse modulation frequency of 10 Hz to 200 Hz, and a pulse duty of 10% to 90%. The method for producing a surface-coated fluororesin substrate according to claim 1 or 2, wherein   A surface-coated fluororesin obtained by the production method according to claim 1, comprising a fluororesin substrate, a surface of the fluororesin substrate, and a graft-polymerized acrylic resin layer. Substrate.   A fluororesin substrate obtained by the production method according to any one of claims 1 to 3, a surface of the fluororesin substrate, a graft-polymerized acrylic resin layer, and another thin film on the acrylic resin layer; A surface-coated fluororesin substrate characterized by comprising: