Patent Application
20250145740
The present invention relates to a method and device for modifying a fluororesin.
A method for hydrophilically modifying a hydrophobic fluororesin has been known.
Patent Document 1 discloses a method in which a substrate 91 made of a fluororesin is brought into contact with the surface of an aqueous ethanol solution 90, and a principal surface 92 of the substrate 91 in contact with the aqueous ethanol solution 90 is irradiated with ultraviolet light from an ArF excimer laser to hydrophilically modify the principal surface 92 (see
Patent Document 1 discloses two methods for irradiating the principal surface 92 with ultraviolet light. As shown in
When the first method is adopted, there are two problems: one is that since the ultraviolet light L8 passes through the substrate 91, only a thin substrate can be processed, and even when a substrate to be processed is thin, the ultraviolet light L8 is absorbed by the substrate 91 so that the amount of the ultraviolet light L8 that reaches the principal surface 92 reduces; and the other is that the fluororesin constituting the substrate 91 is altered by the ultraviolet light L8. When the second method is adopted, there is a problem that the ultraviolet light L9 is absorbed or scattered by the aqueous ethanol solution 90 when passing through the container 93 and the aqueous ethanol solution 90 so that the amount of the ultraviolet light L9 that reaches the principal surface 92 significantly reduces.
In light of these problems, it is an object of the present invention to provide an improved method and device for modifying a fluororesin.
The present invention is directed to a method for modifying a fluororesin, the method including:
In the present invention, ultraviolet light exhibiting intensity in at least a wavelength region of 205 nm or less is used for radicalization of an organic compound including at least one of an oxygen atom and a nitrogen atom in the first step and for radicalization of water in the form of gas or mist in the second step.
Terms used herein will be described. The term “radical” refers to an atom or molecule having an unpaired electron. Although details will be described later, a radical has an unpaired electron and is therefore highly reactive with another molecule. The term “radicalization” refers to producing a radical from a radical source. The term “organic compound including at least one of an oxygen atom and a nitrogen atom” means that the molecular structure of the organic compound has at least one of an oxygen atom and a nitrogen atom.
The first fluid contains an organic compound including at least one of an oxygen atom and a nitrogen atom. The organic compound is present in the form of gas, liquid, or mist in the first fluid. In the first step, the organic compound including at least one of an oxygen atom and a nitrogen atom is radicalized by the ultraviolet light. Radicals obtained from the organic compound including at least one of an oxygen atom and a nitrogen atom hydrophilize the surface of the fluororesin exhibiting hydrophobicity. In the second step, water molecules (H2O) contained in the second fluid are radicalized by the ultraviolet light so that OH radicals and hydrogen radicals are produced. The produced OH radicals and hydrogen radicals hydrophilize the surface layer of the fluororesin. The term “surface layer” includes the surface of the object and the inner part in the vicinity of surface of the object.
In the present invention, ultraviolet light is used for radicalization of the first fluid and the second fluid, and produced radicals are used for hydrophilization of surface layer of the fluororesin. In Patent Document 1, an aqueous ethanol solution is irradiated with ultraviolet light from an ArF excimer laser, but the purpose of irradiation with ultraviolet light in Patent Document 1 is not to radicalize water molecules in the aqueous ethanol solution but to radicalize ethanol molecules in the aqueous ethanol solution. The present invention is greatly different in this point from Patent Document 1.
In the second step, an object to be irradiated with the ultraviolet light is a second fluid containing water in the form of gas or mist. The phrase “second fluid containing water in the form of gas or mist” means that the second fluid has gaseous H2O (i.e., water vapor) or H2O that is in a liquid state but is constituted from particles that can be suspended in the fluid. The amount of attenuation of ultraviolet light due to passing through the second fluid in the form of gas or mist is smaller than the amount of attenuation of ultraviolet light due to passing through water stored in a container, and therefore the fluororesin can be irradiated with a larger amount of ultraviolet light. This makes it possible to more promote hydrophilization than ever before.
The hydrophilization of surface of the fluororesin refers to processing for enhancing the affinity of the surface for water molecules. The hydrophilicity of surface of the fluororesin is enhanced by replacing a fluorine atom present on the surface of the fluororesin with a polar functional group containing no fluorine atom. Although details will be described later, when the fluororesin is modified from hydrophobic to hydrophilic, for example, the fluororesin can tightly be joined with another material.
The second step may be performed after the first step, or the first step and the second step may be performed at the same time. As one of methods for performing the first step and the second step at the same time, a mixed fluid in the form of gas or mist obtained by mixing the first fluid in the form of gas or mist and the second fluid in the form of gas or mist may be irradiated with the ultraviolet light. Although details will be described later, when the mixed fluid is irradiated with the ultraviolet light, the organic compound in the first fluid and water molecules in the second fluid are radicalized at the same time so that the surface layer (i.e., the surface and the inner part in the vicinity of the surface) of the fluororesin is hydrophilized. By hydrophilizing not only the surface but also the inner part in the vicinity of the surface, joint strength is improved. Further, by performing a plurality of steps at the same time, processing time is reduced and a device and a system can be simplified. It should be noted that when the second step is performed after the first step, the first fluid may contain an organic compound present as a liquid.
At least one of the first step and the second step may be performed by irradiating a fluid in contact with the fluororesin with the ultraviolet light. In a case where a fluid in contact with the fluororesin is irradiated with the ultraviolet light, for example, a light source that emits the ultraviolet light and the fluororesin are disposed with a narrow space being interposed therebetween, and in such a state, the fluororesin is irradiated with the ultraviolet light from the light source while the fluid is allowed to flow through the space. This makes it possible to targetably radicalize the fluid that is required for modification processing and is present near the surface of the fluororesin or inside the fluororesin. As a result, many radicals can be brought into contact with the fluororesin.
The organic compound may contain at least one of a hydroxy group, a carbonyl group, and an ether bond. In this case, a functional group containing at least one of a hydroxy group, a carbonyl group, and an ether bond can be formed on the surface of the fluororesin, and therefore high hydrophilicity can be imparted to the surface of the fluororesin.
The organic compound may contain at least one selected from the group consisting of an alcohol, a ketone, an aldehyde, a carboxylic acid, and a phenol.
The organic compound may contain at least one selected from the group consisting of an alcohol having 10 or less carbon atoms and a ketone having 10 or less carbon atoms.
The organic compound may contain at least one selected from the group consisting of an alcohol having 2 or more and 4 or less carbon atoms and acetone. An alcohol having 2 or more and 4 or less carbon atoms and acetone are excellent in easy availability and economic efficiency. An alcohol having 2 or more and 4 or less carbon atoms is excellent in safety and ease of handling. Acetone has a high vapor pressure, which makes it easy to form a relatively high concentration atmosphere.
The organic compound may contain at least one of an amino group, an imino group, and a cyano group.
The organic compound may contain at least one selected from the group consisting of an amine having 4 or less carbon atoms and a nitrile having 4 or less carbon atoms. An amine having 4 or less carbon atoms and a nitrile having 4 or less carbon atoms are excellent in easy availability and economic efficiency.
The ultraviolet light may be produced by a xenon excimer lamp.
The present invention is also directed to a modification device including:
The fluid supply port may be disposed, for example, in the wall or ceiling of the chamber. When there is only one fluid supply port, the fluid supply port is usually connected to both of a supply source of the first fluid and a supply source of the second fluid. However, a combined supply source that supplies both the first fluid and the second fluid may be used. When there is only one fluid supply port and a combined supply source is used, the fluid supply port is connected to the combined supply source. When there is a plurality of fluid supply ports, at least one of the fluid supply ports is connected to a supply source of the first fluid and the other fluid supply port(s) is(are) connected to a supply source of the second fluid. It should be noted that when the fluid supply port is connected to the supply source, a fluid supply channel such as a pipe may be interposed between the fluid supply port and the supply source.
The present invention makes it possible to provide an improved method and device for modifying a fluororesin.
Embodiments of the present invention will be described with reference to the drawings. It should be noted that the drawings disclosed herein merely show schematic illustrations. Namely, the dimensional ratios on the drawings do not necessarily reflect the actual dimensional ratios, and the dimensional ratios are not necessarily the same between the drawings.
Hereinbelow, an embodiment of a fluororesin modification system and an embodiment of a method for modifying a fluororesin using the modification system will be described.
The modification device 20 includes a light source 3 and a fluid supply port 2 connected to the fluid supply source 30. The fluid supply source 30 supplies, to a chamber 5, a first fluid F1 containing an organic compound including at least one of an oxygen atom and a nitrogen atom and a second fluid F2 containing water molecules. The details of the first fluid F1, the second fluid F2, and the fluid supply source 30 will be described later.
Ultraviolet light L1 emitted from the light source 3 is vacuum ultraviolet light and is more specifically ultraviolet light exhibiting intensity in at least a wavelength region of 205 nm or less. The “ultraviolet light exhibiting intensity in at least a wavelength region of 205 nm or less” as used herein is light having an emission band at 205 nm or less. Examples of such light include (1) light exhibiting intensity in a broad wavelength region and showing an emission spectrum whose peak emission wavelength of maximum intensity is 205 nm or less, (2) light showing an emission spectrum having a plurality of maximum intensities (a plurality of peaks), in which any one of the plurality of peaks is located in a wavelength range of 205 nm or less, and (3) light showing an emission spectrum in which integrated intensity of light at 205 nm or less is at least 30% of total integrated intensity.
The light source 3 is, for example, a xenon excimer lamp. The peak emission wavelength of the xenon excimer lamp is 172 nm. Light emitted from the xenon excimer lamp is easily absorbed by the first fluid containing an organic compound including at least one of an oxygen atom and a nitrogen atom and the second fluid containing water in the form of gas or mist. As a result, many radicals are produced from the organic compound including at least one of an oxygen atom and a nitrogen atom and from water molecules.
In the present embodiment, an object to be processed 10 is an object formed of a fluororesin as a whole. However, the object to be processed 10 may be an object not formed of a fluororesin as a whole. The object to be processed 10 is not limited as long as it has, in at least part of the surface thereof, a region where a fluororesin is exposed. The object to be processed 10 may be a rigid plate-shaped substrate, a long flexible film, or an object having a three-dimensional shape other than a plate shape.
Specific examples of the object to be processed 10 include medical fluororesins and printed-wiring boards for high-frequency applications. When the surface of a fluororesin is converted from hydrophobic to hydrophilic, joint strength between the fluororesin and another material can be enhanced. In the case of a printed-wiring board, for example, joint strength between a fluororesin as a base material and a copper plating film can be enhanced, and as a result, an effect that the copper plating is less likely to be peeled off is expected to be obtained.
The mechanism of production of radicals of the first fluid by the modification device will be described. First, a description will be made with reference to a case where the organic compound includes an oxygen atom. Ethanol (C2H5OH) is held up as an example of the organic compound including an oxygen atom. Chemical reaction formulas of the process of producing radicals by irradiating a molecule of ethanol with ultraviolet light (hν) are shown.
As shown by the above formulas (1) to (3), when a molecule of ethanol is irradiated with ultraviolet light (hν), energy of the ultraviolet light breaks a bond between atoms constituting the molecule of ethanol to produce a radical composed of a carbon atom, a hydrogen atom, and an oxygen atom (sometimes referred to as “{CHO} radical”) and a hydrogen radical (sometimes referred to as “H·”). The {CHO} radicals include one having radicalized C and one having radicalized O. Three types of {CHO} radicals shown in the above formulas (1) to (3) are formed depending on which of C and O is radicalized and which of the carbon atoms is radicalized. It is not always true that all the {CHO} radicals are produced in equal proportion.
It should be noted that each of the three chemical reaction formulas represented by the above formulas (1) to (3) shows a case where a {CHO} radical having one atom having an unpaired electron is produced. However, a {CHO} radical having two or more atoms each having an unpaired electron may be produced by irradiation with ultraviolet light.
Hereinbelow, a description will be made with reference to a case where the organic compound includes a nitrogen atom. Ethylamine (C2H5NH2) is held up as an example of the organic compound including a nitrogen atom. Chemical reaction formulas of the process of producing radicals by irradiating a molecule of ethylamine with ultraviolet light (hν) are shown.
As shown by the above formulas (4) to (6), when a molecule of ethylamine is irradiated with ultraviolet light (hν), energy of the ultraviolet light breaks a bond between atoms constituting the molecule of ethylamine to produce a radical composed of a carbon atom, a hydrogen atom, and a nitrogen atom (sometimes referred to as “{CHN} radical”) and a hydrogen radical. The radical is an atom or molecule having an unpaired electron. The {CHN} radicals include one having radicalized C and one having radicalized N. Three types of {CHN} radicals shown in the above formulas (4) to (6) are formed depending on which of C and N is radicalized and which of the carbon atoms is radicalized. It is not always true that all the {CHN} radicals are produced in equal proportion.
It should be noted that each of the three chemical reaction formulas represented by the above formulas (4) to (6) shows a case where a {CHN} radical having one atom having an unpaired electron is produced. However, a {CHN} radical having two or more atoms each having an unpaired electron may be produced by irradiation with ultraviolet light.
Referring to
Fluorine atoms contained in the fluororesin 11 are in a state where they are bonded to carbon atoms. Bond energy between a carbon atom and a fluorine atom is as high as 485 KJ/mol, and therefore a very large amount of energy is required to separate the fluorine atom and the carbon atom by heat or light.
Here, the electronegativity of a fluorine atom is 4.0, and the electronegativity of a hydrogen atom is 2.2. Both of the electronegativities are greatly different from each other. Therefore, electrostatic attraction allows the hydrogen radical to approach the fluorine atom to form HF (hydrogen fluoride), thereby breaking the bond between the fluorine atom and the carbon atom. Bond energy between a hydrogen atom and a fluorine atom is 568 KJ/mol that is higher, and HF is separated from the surface of the fluororesin as a gas, and therefore the production reaction of HF irreversibly proceeds. The {CHO} radical or the hydrogen radical is bonded to a site where fluorine has been extracted from the surface of the fluororesin 11.
The {CHO} functional group represented by (a) in
The {CHO} functional group bonded to the fluororesin 11 is polar. Each of the {CHO} functional groups represented by (b) and (c) in
In addition, when the surface of the fluororesin 11 is hydrophilized by the first step, as shown in
The hydrogen radical present in the inner part in the vicinity of surface of the fluororesin 11 breaks a C—F bond present in the inner part in the vicinity of surface of the fluororesin so that fluorine is extracted. The OH radical is bonded to a site where fluorine has been extracted so that an OH group is produced (see
This is the modification mechanism of surface layer of the fluororesin through a first step and a second step when the first fluid is an organic compound including an oxygen atom. In the modification mechanism, the second step proceeds after the first step in principle. However, both the first step and the second step locally proceed in the chamber in a short period of time. Therefore, the first step and the second step may actually be performed at the same time. This will be described later in detail.
It should be noted that a reaction to produce radicals by irradiating a gas with ultraviolet light proceeds irrespective of pressure, and therefore it is not always necessary to create a reduced-pressure environment in the chamber that is a reaction field. However, in order to replace an atmosphere in the chamber 5 with a desired gas atmosphere in a short time, a vacuum pump may be connected to a fluid discharge port 6 to reduce the pressure in the chamber 5.
Hereinbelow, referring to
In
This is the modification mechanism of surface of the fluororesin through a first step and a second step. In the section “Production of radicals of first gas by modification device” and the section “Modification mechanism”, as the first fluid, ethanol (C2H5OH) is held up as an example of the organic compound including an oxygen atom, and ethylamine (C2H5NH2) is held up as an example of the organic compound including a nitrogen atom. However, the first fluid is not limited to these examples, and any fluid can be used for hydrophilization in the first step as long as it contains an organic compound including at least one of an oxygen atom and a nitrogen atom.
However, the organic compound including an oxygen atom preferably contains at least one of a hydroxy group, a carbonyl group, and an ether bond. In this case, a functional group containing at least one of a hydroxy group, a carbonyl group, and an ether bond can be formed on the surface of the fluororesin, and therefore high hydrophilicity can be imparted to the surface of the fluororesin. Particularly, the organic compound including an oxygen atom preferably contains at least one selected from the group consisting of an alcohol, a ketone, an aldehyde, a carboxylic acid, and a phenol. Further, the organic compound including an oxygen atom preferably contains at least one selected from the group consisting of an alcohol having 10 or less carbon atoms and a ketone having 10 or less carbon atoms. Among them, an alcohol having 2 or more and 4 or less carbon atoms and acetone are excellent in easy availability and economic efficiency. Particularly, an alcohol having 2 or more and 4 or less carbon atoms is excellent in safety and ease of handling. Acetone has a high vapor pressure, which makes it easy to form a relatively high concentration atmosphere. The organic compound including a nitrogen atom preferably contains at least one of an amino group, an imino group, and a cyano group. Particularly, at least one selected from the group consisting of an amine having 4 or less carbon atoms and a nitrile having 4 or less carbon atoms is more preferred. For example, methylamine, ethylamine, or acetonitrile is preferred.
Referring to
The carrier gas G1 is, for example, an inert gas such as nitrogen gas. The fluid supply source 30 can feed a mixed fluid obtained by mixing the first fluid F1 containing the carrier gas G1 and ethanol gas and the second fluid F2 containing water vapor to the modification device 20 through the fluid supply pipe 56. It should be noted that the second fluid F2 may contain water in the form of mist in addition to water vapor.
The fluid supply source 30 can adjust a mixing ratio between ethanol gas, water vapor, and the carrier gas G1 in the mixed fluid in the modification device 20 by adjusting the amount, temperature, or ethanol concentration of the aqueous ethanol solution 51. The amount of the carrier gas G1 to be supplied can be adjusted using a valve 54 by checking a flowmeter 53. A supply pipe may be provided to supply the aqueous ethanol solution 51 to the container 55. A discharge pipe may be provided to discharge the aqueous ethanol solution 51 from the container 55. A heater may be provided to control the temperature of the aqueous ethanol solution 51 in the container 55. The aqueous ethanol solution 51 used in the present embodiment is one obtained by mixing anhydrous ethanol and water in a ratio of 1:1. It should be noted that anhydrous ethanol herein refers to high-concentration ethanol containing 95 vol % or more of ethanol.
Referring to
The modification device 20 is used, for example, in the following procedure. A transport mechanism (not shown) transports an object to be processed 10 from the outside of the modification device 20 onto the table 15. A first fluid F1 and a second fluid F2 are supplied into the chamber 5 through the fluid supply port 2 to replace air in the chamber 5 with the first fluid F1 and the second fluid F2. After the completion of the replacement, modification processing is performed by turning on the light source 3 while the first fluid F1 and the second fluid F2 are continued to be supplied to the chamber 5. After the completion of the modification processing, the light source 3 is turned off, supply of the first fluid F1 and the second fluid F2 is stopped, and the object to be processed 10 on the table 15 is transported to the outside of the chamber 5.
The fluid supply source and the modification device may variously be modified. Modifications of the fluid supply source and the modification device will be shown.
Referring to
A carrier gas supply pipe 62 is inserted into the ethanol solution 61, and a carrier gas G1 is fed through the carrier gas supply pipe 62 to vaporize the ethanol solution 61 by bubbling. In this way, a first fluid F1 containing the carrier gas G1 and ethanol gas is extracted. The ethanol solution 61 is preferably high-concentration ethanol or anhydrous ethanol. The ethanol solution 61 may be an aqueous ethanol solution.
A carrier gas supply pipe 72 is inserted into the water 71, and a carrier gas G2 is fed through the carrier gas supply pipe 72 to vaporize the water 71 by bubbling. In this way, a second fluid F2 containing the carrier gas G2 and water vapor is extracted. It should be noted that the water 71 may be vaporized by heating, the water 71 may be vaporized by stirring, or the water 71 may be vaporized by applying ultrasonic vibration. As described above, water contained in the second fluid F2 does not always have to be water vapor, and may be water mist suspended in the carrier gas G1.
A pipe 66 through which the first fluid F1 flows and a pipe 76 through which the second fluid F2 flows are joined together at a joint portion 67 and connected to the modification device 20. It should be noted that the pipe 66 and the pipe 76 may separately be connected to the modification device 20 without joining them together. The carrier gas G1 and the carrier gas G3 may be the same or different from each other.
The mixing ratio between the first fluid F1 and the second fluid F2 can be adjusted by adjusting the flow rate ratio between the carrier gas G1 and the carrier gas G2. At the joint portion 67, a flow rate adjusting valve may be disposed to adjust the mixing ratio between the two fluids.
By flowing the carrier gas G1 without flowing the carrier gas G2, the first fluid F1 can be fed to the modification device without feeding the second fluid F2 to the modification device 20. On the other hand, by flowing the carrier gas G2 without flowing the carrier gas G1, the second fluid F2 can be fed to the modification device 20 without feeding the first fluid F1 to the modification device 20. Further, at the joint portion 67, a three-way valve may be disposed to switch flow between the two fluids. The timing of supply of the first fluid F1 can be made different from the timing of supply of the second fluid F2.
Referring to
Referring to
Each of the light sources 3 is housed in a tube 33 that extends from the front to back of the drawing. At least part of the tube 33 opposed to the object to be processed 10 is made of a material that transmits ultraviolet light L1, such as quartz glass. A space 34 between the light source 3 and the tube 33 is filled with an inert gas that is less likely to absorb ultraviolet light. The tube 33 prevents an altered substance of the fluid contained in an atmosphere from adhering to the surface of the light source 3 to prevent a reduction in the irradiance of the light source 3.
As shown in
Referring to
In the present embodiment, only a region required to be modified in the object to be processed 10 can selectively be processed by relatively moving the object to be processed 10 and the tip 47 while maintaining a gap between the object to be processed 10 and the tip 47 of the pipe 46. Further, in the present embodiment, an entire processing space surrounded by a chamber, or the like may not be filled with the second fluid F2. It should be noted that the modification device 22 can be used in the same manner also when a first fluid F1 is used and when a mixed fluid of the first fluid F1 and the second fluid F2 is used.
The embodiment of the modification system and the modifications of the fluid supply source and the modification device constituting the modification system have been described above. However, the present invention is not limited to the embodiment and modifications described above, and two or more of the modifications may be combined and various changes or modifications may be made to the embodiment and the modifications without departing from the spirit of the present invention.
The effect of the above-described modification method was verified by ATR-FTIR analysis and an experiment of contact angle measurement.
As objects to be processed 10, five PTFE (polytetrafluoroethylene) substrates manufactured by Yodogawa Hu-Tech Co., Ltd. were prepared. Four of the five substrates were processed using the modification system 100 according to the embodiment shown in
Common processing conditions are as follows. In the chamber 5, the substrate was disposed at a distance of 1 mm from the light source 3. As the light source 3, a xenon excimer lamp having a peak wavelength of 172 nm was used. The irradiance on the surface of the light source 3 was 30 mW/cm2. Nitrogen gas was fed at 2 L (2×10−3 m3)/min as the carrier gas G1 to vaporize a liquid in the container 55 by bubbling. As will be described later, the liquid is different depending on the type of sample.
Samples S1 to S5 respectively have the following features.
The sample S1 is a substrate (PTFE resin) not subjected to modification processing.
The sample S2 is a sample irradiated with ultraviolet light for 30 seconds in an ethanol gas atmosphere. That is, the sample S2 is a sample obtained by performing only the first step for 30 seconds.
The sample S3 is a sample irradiated with ultraviolet light for 120 seconds in an ethanol gas atmosphere. That is, the sample S3 is a sample obtained by performing only the first step for 120 seconds.
The sample S4 is a sample irradiated with ultraviolet light for 30 seconds in a vaporized aqueous ethanol solution atmosphere. That is, the sample S4 is a sample obtained by performing the first step and the second step for 30 seconds. The aqueous ethanol solution is a liquid obtained by mixing 10 mL (1×10−5 m3) of anhydrous ethanol and 10 mL (1×10−5 m3) of water.
The sample S5 is a sample irradiated with ultraviolet light for 120 seconds in a vaporized aqueous ethanol solution atmosphere. That is, the sample S5 is a sample obtained by performing the first step and the second step for 120 seconds. The aqueous ethanol solution used for S5 is the same as that used for S4.
An O—H bond in the surface layer shows strong absorption at a wavenumber of about 3300 to 3400 cm−1. A C—H bond in the surface layer shows strong absorption at a wavenumber of about 2900 to 3000 cm−1. As can be seen from
The unprocessed sample S1 hardly contains an O—H bond, a C—H bond, and a C═O bond. From this fact, it was found that O—H bonds, C—H bonds, and C═O bonds were formed by modification of surface layer of the fluororesin. Further, the degree of modification of surface layer of the sample decreases in order of S5, S4, S3, S2. From this fact, it was found that the surface layers of the samples S4 and S5 subjected to modification processing in an aqueous ethanol solution atmosphere were more modified than the surface layers of the samples S2 and S3 subjected to modification processing only in an ethanol gas atmosphere and that the surface layers of the samples S3 and S5 subjected to processing for 120 seconds were more modified than the surface layers of the samples S2 and S4 subjected to processing for 30 seconds.
The surface layer of an object to be processed 10 was subjected to hydrophilization processing using the modification system 100 according to the embodiment shown in
The horizontal axis represents the processing time of the object to be processed 10, and the vertical axis represents the water contact angle of surface of the object to be processed 10. A smaller water contact angle indicates that the degree of hydrophilization is higher.
As shown in
As can be seen from
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-009876 | Jan 2022 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2022/040629 | 10/31/2022 | WO |
