JP3014897B2 - Surface treatment method for polymer material molded body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface treatment method for converting the surface of a molded article of a polymer material to hydrophilic or increasing the hydrophilicity.

[0002]

2. Description of the Related Art As a technique related to the present invention, there is, for example, Japanese Patent Laid-Open Publication No. 2-7353, in which a discharge vessel is filled with a discharge gas for forming excimer molecules, and a dielectric barrier is provided. Discharge (also known as ozonizer discharge or silent discharge)
A description is given of a radiator that forms excimer molecules and extracts light emitted from the excimer molecules, that is, a dielectric barrier discharge lamp. On the other hand, various methods have been proposed for changing the surface of the molded polymer material to hydrophilic. Since the polymer material molded product has low polarity in chemical structure and high crystallinity, it is often difficult to adhere, print, paint, and dye it on its surface. In order to perform these, it is necessary to change the surface of the polymer material molded article to be hydrophilic. The main ones of the prior art are as follows. Examples include a flame treatment method, a chromic acid treatment method, a corona discharge treatment method, a plasma treatment method, and an ultraviolet irradiation method using a mercury lamp or the like.

[0003] In the flame treatment method, the surface of a molded article is treated with a gas oxidizing flame, but deformation and melting due to heat may occur. The problem with the chromic acid treatment method is the treatment of the chemicals used. The corona discharge treatment method is a method in which a film is passed through a gap between an electrode and a metal roll and a high voltage is applied to perform treatment. There is a problem that processing is difficult except for the film form. In the plasma processing method, low-temperature plasma is applied to the surface of a polymer material molded body at a low pressure to perform processing. Chemical changes occur on the surface due to electrons, ions, ultraviolet rays, and the like. The cost of processing equipment is large,
Another drawback is that it is basically a batch process and cannot be a continuous process. Further, the above-mentioned ultraviolet treatment method requires time, and there are substances which cannot be hydrophilized such as fluororesins.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for converting the surface to hydrophilic or increasing the hydrophilicity, which can be applied to the surface of various low-active polymer material molded articles. is there.

[0005]

The object of the present invention can be achieved by irradiating an object to be irradiated with a dielectric barrier discharge lamp in a radiation band in which the maximum value of the wavelength of emitted light is 180 nm or less.

[0006]

In the dielectric barrier discharge lamp, when xenon is used as a discharge gas, a dielectric barrier discharge lamp having radiation in a wavelength range of 160 to 190 nm having a maximum value at 172 nm can be obtained. Similarly, when krypton, argon, and fluorine are used as the discharge gas, the maximum wavelengths of radiation are 155, 126, and 158 nm, respectively.
The wavelength ranges are 140-160, 107-165, respectively.
A dielectric barrier discharge lamp in the wavelength range from 130-190 nm is obtained.

When these lamps irradiate a polymer material molded body placed in an atmosphere containing air, oxygen, or water vapor, or a nitrogen atmosphere, or an inert atmosphere such as argon, a low-pressure mercury lamp conventionally used is used. Since the photon energy is higher than the emission wavelengths of 185 nm and 254 nm, the ability to cut C—H bonds and the like on the surface of the molded polymer material is high, and at the same time, carbon, oxygen, water, etc. Is an OH group, COOH
It becomes a base and has a high degree of bonding to the surface. As a result, compared to the conventional UV treatment with a mercury lamp,
Conversion of the polymer material molded body into hydrophilicity, which has been difficult, becomes possible.

In order to achieve irradiation, the dielectric barrier discharge lamp is easier to handle if it has a window member through which the emitted light passes. As the window member, synthetic quartz glass is used when the discharge gas is xenon gas, sapphire is used as the window member when the discharge gas is krypton or fluorine gas, and magnesium fluoride is used as the window member when the discharge gas is argon. Can be applied. Alternatively, the object to be irradiated can be placed in a discharge gas atmosphere and directly irradiated with radiation light from the discharge without a window member. The latter is similar to the plasma processing method, but in the case of the plasma processing, since the operating pressure is several torr, an evacuation device is always required, whereas the operation of the method of the present invention is from 0.2 atm to several atm. Therefore, a vacuum device is not necessarily required, and high throughput can be realized.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described. FIG. 1 shows a schematic diagram of a method for hydrophilizing polyethylene terephthalate using a dielectric barrier discharge lamp. In the processing duct 1, dielectric barrier discharge lamps 2a, 2b, 2c, 2d, and 2e are provided near a polyethylene terephthalate molded plate 3 which is an object to be irradiated. The dielectric barrier discharge lamp can be used by the cooling means without reducing the radiation intensity even if the surface temperature is suppressed to 100 ° C. or less, so that the lamp can be sufficiently cooled and used close to the sample. For example, the temperature of the formed plate 3 does not rise so much even when it approaches 1 mm to 50 mm.

FIG. 2 is a schematic view of the above-mentioned dielectric barrier discharge lamp. The discharge vessel 4 is made of quartz glass having a total length of about 300 mm, and has an inner tube 5 (outer diameter of 24 mm) and an outer tube 6 (outer diameter of 34 mm).
mm) is coaxially arranged to form a hollow cylindrical shape. The inner tube 5 and the outer tube 6 also serve as a dielectric for the dielectric barrier discharge and a light extraction window member, and an outer surface of the outer tube 6 is provided with an electrode 7 made of a metal mesh that transmits light. A cylindrical metal electrode 8 also serving as an ultraviolet reflector is provided on the inner surface of the inner tube 5. Cooling fluid 9 is flowed inside the cylindrical electrode 8 to lower the temperature of the entire dielectric barrier discharge lamp. A getter 10 is provided at one end of the discharge vessel 4. Xenon gas of about 350 torr is sealed in the discharge space 11 as a luminescent gas, and when turned on by the power supply 12, emits ultraviolet rays having a maximum value at 172 nm in a wavelength range of 120 to 190 nm.

The atmosphere is performed in air or a gas in which air and oxygen are mixed with nitrogen at an appropriate concentration. In the case of the latter gas 14, it is supplied from the processing fluid supply port 13. The ultraviolet rays cut chemical bonds on the surface of the molded product, and oxygen, carbon, and moisture present on the atmosphere and on the surface of the irradiation object are introduced into the surface of the polyethylene terephthalate as COOH groups and OH groups. FIG. 3 shows the dependence of the contact angle of water on the polyethylene terephthalate surface with the ultraviolet irradiation time. In the figure, the solid line is data for a dielectric barrier discharge lamp, and the dotted line is data for a conventional low-pressure mercury lamp for comparison. The atmosphere was 1 atm of air and the distance between the lamp and the sample was 2 mm. The processing time required for the low-pressure mercury lamp in several minutes was 30 seconds in the method of the present invention. At the same time, O _1S / C _1S was measured by the analyzer ESCA.
Indicated by a dotted line. ), 0.5 before irradiation, increased to 0.8 after irradiation for 30 seconds, and it was confirmed that COOH groups and OH groups were introduced to the surface.

A second embodiment of the present invention will be described. In this embodiment, the lamp does not have a window member, and directly utilizes ultraviolet rays emitted from discharge. The discharge gas is krypton gas, and the object to be irradiated is a polyethylene molded body, and a schematic diagram thereof is shown in FIG. A Kr gas 21 serving as a discharge gas is introduced from a supply port 13. Electrode groups 15a, 15b and 15c are provided in a reaction vessel 17 having a vacuum exhaust port 16. Electrode group 15
The structure of a, 15b and 15c is a metal hollow cylinder 1 having an outer diameter of 9 mm and a total length of 200 mm as shown in the longitudinal sectional view of FIG.
8 and the material is stainless steel. The dielectric 19 is quartz glass. Flow water and air through the hollow portion 20 of the electrode,
Cooling. The power supply 12 and the electrodes are connected as shown in the figure, and a dielectric barrier discharge 24 is performed between the electrodes 15a and 15b, and 15b and 15c. Release. The power is about 300W. The distance between the electrode and the irradiation target 3 is 50 mm. By irradiation for 2 minutes, the contact angle of water on the polyethylene surface changed from 93 degrees to 43 degrees. The low-pressure mercury lamp changed only to 80 degrees. Even when the discharge gas is krypton, there is a method in which a window member that transmits emitted ultraviolet rays, such as sapphire or magnesium fluoride, is used as a discharge vessel, such as a lamp having the structure used in the first embodiment. . Polypropylene and polyacetal can be treated in the same manner.

A third embodiment of the present invention will be described. The discharge gas is an argon gas, and the object to be irradiated is a fluororesin, and a schematic diagram thereof is shown in FIG. The fluorine resin 3 as the object to be processed is supplied with argon gas 22 from the supply port 13 from above, and is transported by the transport device 23 to the processing duct 1 filled with an argon atmosphere, and then the electrode groups 15a, 15b, 15
c from the dielectric barrier discharge 24 to a wavelength range of 107 nm-1
It is irradiated with 65 nm ultraviolet rays. In this embodiment, since the argon gas pressure is equal to or higher than the atmospheric pressure, there is an advantage that a vacuum vessel is not required and the movement of the object to be processed is simple. At a power of 300 W, the contact angle of water on the surface of polytetrafluoroethylene changed from 103 to 42 degrees by irradiation for 2 minutes. Irradiation with a low-pressure mercury lamp in an air atmosphere changed only to 102 degrees.

FIG. 7 shows a contact angle when a polyethylene terephthalate resin, a polyethylene resin, and a fluororesin are selected as objects to be irradiated, and irradiation is performed by a dielectric barrier discharge lamp using argon, krypton, fluorine, and xenon gas as a discharge gas. Shows the change in In the figure, □ indicates a data value for fluororesin (PTFE), + indicates polyethylene, and Δ indicates data values for polyethylene terephthalate. All processing times were 2 minutes. The horizontal axis indicates the maximum intensity wavelength of the ultraviolet light radiated from the barrier discharge when each discharge gas is used, in the unit of nm. Polyethylene terephthalate was all hydrophilized by ultraviolet rays emitted from argon, krypton, fluorine and xenon gas. Polyethylene was also hydrophilized by ultraviolet rays emitted from all discharge gases. Polyethylene was also hydrophilized by ultraviolet rays radiated from all discharge gases, but xenon gas was less effective at 60 degrees. In the case of fluororesin (PTFE), the value was 65 degrees with krypton gas and 42 degrees with argon gas. Xenon gas did not hydrophilize. Although a low-pressure mercury lamp, which is a conventional ultraviolet treatment, is shown, the change in the contact angle is smaller in each of the irradiation objects than in the dielectric barrier discharge lamp.

[0015]

As described above, according to the present invention, it is possible to provide a method capable of hydrophilizing the surface of a molded polymer material at high speed with a small apparatus.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a method for hydrophilizing polyethylene terephthalate.

FIG. 2 is an explanatory diagram of an example of a dielectric barrier discharge lamp used in the present invention.

FIG. 3 is an explanatory diagram of data of hydrophilization.

FIG. 4 is an explanatory view of a method for hydrophilizing a polyethylene molded article.

FIG. 5 is an explanatory diagram of an example of a discharge electrode used in the present invention.

FIG. 6 is an explanatory view of a method for hydrophilizing a fluororesin.

FIG. 7 is an explanatory diagram of data of hydrophilization.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Processing duct 3 Forming plate 4 Discharge vessel 5 Inner tube 6 Outer tube 7, 8 electrode 9 Cooling fluid 10 Getter 11 Discharge space 12 Power supply 23 Transport device 24 Dielectric barrier discharge

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-128947 (JP, A) JP-A-3-269024 (JP, A) JP-A-4-318037 (JP, A) US Patent 3,748,484 (US , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C08J ^7/ 00-7/18

Claims (3)

(57) [Claims] 1. The wavelength at which the spectral radiation intensity is maximum is 180n.
m or less, and irradiates ultraviolet rays emitted from a dielectric barrier discharge lamp to the polymer material molded article to change the surface of the polymer material molded article to hydrophilicity or to increase the hydrophilicity. Surface treatment method. 2. The molded article of a polymer material is a polyethylene resin,
Or, it is a polypropylene resin or a polyacetal resin, and the dielectric barrier discharge lamp contains a gas containing xenon, krypton, argon or fluorine as a discharge gas and has a radiation wavelength range of 16 nm.
0-190, 140-160, 107-165, 130
The surface treatment method according to claim 1, wherein the dielectric barrier discharge lamp has radiation light in at least one wavelength range of -190. 3. The polymer material molded article is a fluororesin,
The dielectric barrier discharge lamp contains a gas containing krypton, argon or fluorine as a discharge gas, and has a radiation wavelength range of 140-160, 107-1 expressed in nm.
The surface treatment method according to claim 1, wherein the dielectric barrier discharge lamp has radiation light in at least one wavelength range of 65, 130 to 190.