JPH04370123A - Production of modified fluororesin - Google Patents

Abstract

PURPOSE:To facilitate further development of application by treating a fluororesin having a low surface energy and improving wettability, printability, adhesion, etc. CONSTITUTION:A polymerizable monomer is brought into contact with a fluororesin and an excimer laser is applied thereto to polymerize the above- mentioned monomer to the fluororesin.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel method for producing modified fluororesins.

0002

[Prior art] Polytetrafluoroethylene (PTFE)
Fluororesins represented by ) have excellent properties such as heat resistance, abrasion resistance, weather resistance, and chemical resistance, and are used in a wide range of applications.

However, although fluororesins have excellent properties as mentioned above, they have low surface energy, poor wettability,
This has been an obstacle to its application to applications that require printability, adhesion, etc. In order to eliminate this obstacle and further expand the use of fluororesin, methods for modifying fluororesin include the sodium treatment method and the ArF laser irradiation method (Japanese Unexamined Patent Publication No. 2-196
No. 834) is known.

0004

[Problems to be Solved by the Invention] The sodium treatment method is a method in which the surface of a fluororesin molded article is brought into contact with a solution of metallic sodium in tetrahydrofuran or liquid ammonia, but this treatment liquid can ignite or explode when it comes into contact with moisture. Its handling is troublesome.

On the other hand, the ArF laser irradiation method is a method of modifying the fluororesin by irradiating the fluororesin with an ArF laser in an atmosphere of boron compounds or aluminum compounds, and it does not have the disadvantages of using a treatment liquid like the sodium treatment method. However, there is a problem in that special gases such as boron compounds or aluminum compounds must be prepared.

[0006]

[Means for Solving the Problems] As a result of intensive research to solve the above-mentioned problems of the prior art, the inventors of the present invention have proposed to bring a fluororesin into contact with a polymerizable monomer, and to bring the fluororesin and the monomer into contact with each other. The present inventors have discovered that a modified fluororesin can be easily obtained by irradiation with an excimer laser, and have completed the present invention.

That is, the method for producing a modified fluororesin according to the present invention involves bringing a fluororesin into contact with a polymerizable monomer,
It is characterized in that the monomer is polymerized into a fluororesin by irradiating the monomer with an excimer laser.

In the present invention, first, a fluororesin is brought into contact with a polymerizable monomer. The fluororesin and the polymerizable monomer can be brought into contact by dipping the fluororesin in the monomer or its solution, applying the monomer or its solution to the fluororesin by spraying, or placing the fluororesin in a monomer atmosphere. It can be carried out. Note that when the monomer is used as a solution, the concentration is usually about 0.1 to 30% by weight.

The fluororesins used here include PTFE, tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and ethylene-tetrafluoroethylene copolymer (FEP). ETFE), polychlorotrifluoroethylene (PCTFE), or the like. These fluororesins are usually used in the form of a predetermined shape such as a film, rod, or tube, but they may also be in the form of powder.

Furthermore, various polymerizable monomers can be used without particular limitation as long as they can be polymerized by excimer laser irradiation, such as acrylic acid, methyl acrylate, ethyl acrylate, etc. Acrylic acid esters, methacrylic acid and its esters, acrylamide, acrylamide derivatives such as 2-acrylamido-2-methylpropanesulfonic acid and N,N-dimethylaminopropylacrylamide, styrene, styrene derivatives such as sodium styrene sulfonate, allylamine etc. can be cited as specific examples. These monomers are selected and used depending on the purpose of modifying the fluororesin.

In the present invention, the fluororesin and the polymerizable monomer are brought into contact with each other in this way, and the excimer laser is irradiated onto the contact. Excimer laser irradiation conditions are set appropriately depending on the type of monomer, etc., but usually the energy density is about 20 to 60 mJ/cm2, and the number of repetitions is 10 to 60.
Hz, and the irradiation time is about 1 to 10 minutes.

Irradiation of the fluororesin with excimer laser may be carried out simultaneously with the contact with the polymerizable monomer, or may be carried out after the contact. In order to simultaneously bring the polymerizable monomer into contact with the fluororesin and irradiate it with excimer laser, for example,
A monomer or its solution is placed in a tank, a fluororesin is introduced into the tank, and an excimer laser is irradiated. In addition, in order to perform excimer laser irradiation after contact between the fluororesin and the monomer, for example, the monomer or its solution is placed in a tank, the fluororesin is introduced into the tank, and the fluororesin is pulled up.
Next, excimer laser irradiation is performed.

[0013] When the fluororesin and the polymerizable monomer are irradiated with an excimer laser while they are in contact with each other, the monomers undergo graft polymerization using the fluororesin as a backbone polymer. The wettability, printability, adhesion, etc. of the fluororesin are improved depending on the type of branched polymer formed on the surface of the fluororesin by graft polymerization. Although the grafting rate is not particularly limited, it is usually about 1 to 30%.

[0014]

[Examples] The present invention will be explained in more detail with reference to Examples below.

Example 1 A PTFE film with a thickness of 0.1 mm was immersed in a 30% by weight aqueous solution of ethyl acrylate and pulled up, and both sides of the film were coated with an energy density of 40 mJ/cm2 and a repetition rate of 30 Hz.
An ArF laser (wavelength 193 nm) was applied vertically to
After irradiation for a minute, the ethyl acrylate homopolymer was removed by washing with water and further dried to obtain a modified PTFE film in which ethyl acrylate was graft copolymerized on the surface of the PTFE film. The grafting rate of this modified PTFE film is 5%, and the contact angle of water with the surface is 25°C.
at 80° (that of untreated PTFE film is 122°)
Met.

Example 2 A PTFE film with a thickness of 0.1 mm was immersed in a 20% by weight aqueous solution of N,N-dimethylaminopropylacrylamide and pulled up, and an energy density of 60 mJ/
ArF laser is vertically irradiated for 5 minutes under the conditions of cm2 and repetition rate of 20 Hz.

Next, the homopolymer was removed by washing with water and dried in the same manner as in Example 1 to obtain a modified PTFE film in which N,N-dimethylaminopropylacrylamide was graft copolymerized on the surface of the PTFE film.

The grafting ratio of this modified PTFE film was 3%, and the contact angle of water to the surface was 20°. In addition, an adhesive (manufactured by Konishi Co., Ltd., trade name: E set) was applied to this modified surface, and after adhering it to a steel plate and leaving it at 80°C for 1 hour, it was applied at a tensile rate of 200 mm/min and a temperature of 25°C. When the adhesive strength was measured by a peeling method, it was found to be 0.84 kg/1 cm width. When a similar test was conducted on untreated PTFE, the adhesive strength was approximately 0 kg/1c.
It was m wide.

Example 3 A PTFE film with a thickness of 0.1 mm was introduced into a transparent cell substituted with allylamine vapor, and while the film was in contact with allylamine vapor, an energy density of 60 mJ/c was applied.
ArF laser is vertically irradiated for 1 minute under conditions of m2 and repetition rate of 30 Hz.

Next, the homopolymer was removed by washing with water and dried in the same manner as in Example 1 to obtain a modified PTF in which allylamine was graft copolymerized on the surface of the PTFE film.
An E film was obtained.

[0021] The frictional charging voltage of this modified PTFE film was measured using a rotary static tester and was found to be 350V. In addition, 200 mm was used as a friction body in the measurement.
Using a cotton cloth with a tension of g, friction was applied at a rate of 750 times/minute, and the charged voltage was measured 1 minute after the start of the friction. Untreated PTF
When a similar test was conducted on E film, the charging voltage was 79
It was 00V.

[0022]

Effects of the Invention The present invention is constructed as described above, and a modified fluororesin can be obtained by a simple method of irradiating the fluororesin with an excimer laser while bringing the polymerizable monomer into contact with the fluororesin.

Claims (1)

[Claims] 1. A method for producing a modified fluororesin, which comprises bringing the fluororesin into contact with a polymerizable monomer and irradiating the monomer with an excimer laser to polymerize the monomer into a fluororesin.