JP3213659B2 - Surface Modification Method for Fluororesin Tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for modifying the surface of a fluororesin tube, and more particularly to a method for modifying the outer surface of an ethylene-tetrafluoroethylene copolymer (ETFE) tube.

[0002]

2. Description of the Related Art As is well known, fluorine resins have excellent properties such as non-adhesion, heat resistance, non-toxicity, weather resistance and chemical resistance. In particular, among fluororesins, ETFE is a type of fluororesin having both the characteristics of the above fluororesin and excellent processability, and can be processed by any method such as melt processing, extrusion molding and injection molding, and has excellent economical efficiency. To demonstrate.

[0003] Adhesion of a heterogeneous material, ie, rubber or other resin, to a tube of ETFE to form a composite material has been required to provide functionalities and improve physical properties in applications in the fields of electronics, chemistry, and machinery. Is very significant to do. Among them, the liquid fuel supply piping system is E
A composite material of a TFE tube and a polymer has been studied, and is extremely effective for its use. And
In order to impart adhesiveness, it is useful to perform surface modification such as improving the wettability of the tube surface. This surface modification technique for fluorine resin is roughly classified into a wet method and a dry method. The wet method is a method in which a fluorine resin is impregnated in a solution in which metallic sodium is dissolved together with naphthalene in a solvent such as tetrahydrofuran and the like, and the surface is chemically modified. On the other hand, in the dry method, corona discharge treatment performed at atmospheric pressure, ion implantation and plasma treatment performed under reduced pressure conditions, and the like can be considered.

[0004] The corona discharge treatment is a kind of gas discharge. When the electric field between conductors is not equal, a luminous discharge that appears when a partial electric breakdown occurs at a large electric field on the surface before a spark discharge is used. It is a physical method of shaving the surface. In the ion implantation, a material to be processed is set in a vacuum vessel of the implantation apparatus, and the degree of vacuum is set to 10 ⁻⁵ to 10 ⁻⁶ Torr.
Metals such as titanium are evaporated and ionized by the local high current of the arc spot at the r level to form neutral plasma, and then the titanium ions are accelerated, the beam is accelerated, and the material is irradiated as a beam to modify the material. Further, in the plasma treatment, a material to be treated is set in a vacuum vessel, and a plasma is produced with an argon gas or oxygen under a certain degree of vacuum, and various components in the plasma, that is, ions, electrons, radicals and This is a method of improving and modifying the surface structure of a material with excited atoms and molecules.

[0005]

However, according to the prior art, there are the following problems. 1. Wet method It was necessary to prepare a solution or suspension in advance, and a process such as washing was required after the treatment, and there was no time advantage in obtaining a final product. Further, the adhesion between the treated material and rubber or the like has been considerably varied in strength. 2. Dry method The dry method is a relatively clean method.
A practically sufficient adhesive strength cannot be obtained by ion implantation or conventional plasma treatment. Particularly in the case of plasma processing, almost no attempt has been made for a tube as in the present invention.

The present invention has been made in view of such circumstances, and has been developed in a clean environment, the manufacturing process is relatively simple, and the bonding strength with rubber or the like is high enough for practical use. It is an object to provide a reforming method.

[0007]

SUMMARY OF THE INVENTION The present invention has a fluorine
The reactor where the resin tube is placed and the outer periphery of this reactor
A ring electrode for plasma generation attached to the section,
A plug having a high frequency power supply connected to the ring electrode.
Surface modification of fluororesin tubes using a plasma machine
Using air as the processing gas and an oscillation frequency of 1
3.56 MHz, pressure of processing gas 0.02 to 1.5 To
rr, by treatment with 15 to 60 seconds by a plasma generated under conditions of high-frequency output 25～200W, the dollar
This is a method for modifying the surface of a fluororesin tube, which comprises modifying the outer peripheral surface of a fluororesin tube.

In the present invention, the reason for using nitrogen gas or air as the gas for plasma generation is that the properties of the gas are extremely safe and inexpensive, and that sufficient chemical species for performing surface modification in the generated plasma are used. This is because it can be generated.

In the present invention, the reason that the gas pressure of the processing gas is set to 0.02 to 1.5 Torr is that the plasma itself is difficult to generate in a region other than the vacuum degree in this range, and even if the plasma is generated, the concentration of the plasma is reduced. This is because it is extremely thin and does not play a role of surface modification. In the present invention,
A high-frequency output of 25 to 200 W and a processing time of 15 to 60 seconds is not very effective as an effect of imparting adhesiveness with a longer output and processing time. This is because the internal temperature increases and affects the dimensional stability of the ETFE tube. In addition, because of the relatively low output and the relatively short processing time, it is possible to develop the ETFE tube for continuous surface treatment.

FIG. 1 shows a plasma processing apparatus according to the present invention. Reference numeral 1 in the drawing denotes, for example, a reactor made of Pyrex glass having an inner diameter of 90 mm. In this reactor 1, ETF
A tube set jig 3 on which the E tube 2 is placed is arranged. Further, the reactor 1 is connected with a pipe 4 for an inlet for a plasma gas and an exhaust pipe 5 leading to a rotary pump (not shown) for evacuating the inside of the reactor 1 to a vacuum. A ring electrode 6 for generating plasma is closely attached to an outer peripheral portion of the reactor 1, and is connected so as to receive a signal from a matching box 7 for adjusting output and a high frequency power supply 8. ing.
In addition, a vacuum gauge (not shown) is arranged in the reactor 1.

[0011]

According to the present invention, the surface of the ETFE tube can be modified (giving adhesion) in a clean environment with a relatively simple manufacturing process and in a short time.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. First, the tube set jig 3 on which ETFE is arranged is placed in the reactor, and the inside of the reactor 1 is set to 0.05 Torr.
r Reduce the pressure to below. Subsequently, air as a plasma gas is introduced to adjust the internal pressure of the reactor to 0.4 Torr. Thereafter, the oscillation frequency is set to 13.56 MHz and the output is set to 100 W from the high frequency power supply 8, and plasma is generated in this state, but this is maintained for 30 seconds.

As a result, the previously set ETFE
The plasma physically and chemically acts on the outer peripheral surface of the tube, and the outer peripheral surface of the tube is surface-modified. Then, FT-IR, wettability index, contact angle, and peel strength of a hot pressed product with urethane rubber were measured as evidence of the surface modification. Figure 2 shows FT-I of untreated ETFE tube
FIG. 3 shows the spectrum of the ETFE tube according to the present embodiment. Here, FIG. 3 is a difference spectrum used as a method for prominently expressing the difference between the spectrum of the processed product of the present invention and the spectrum of the unprocessed product (FIG. 2).

2 and FIG.
Around 0 cm ^-1 (from -CH group), 1600 cm ^{-1 to} 1800
Around cm ^-1 (from -C = C- group or carbonyl group) and around 3500 cm ^-1 (from -NH group or -OH group)
The peak has increased. Therefore, it is presumed that these polar groups have a structure existing by the plasma treatment. Also, the measurement result of the coating index with the coating index standard solution,
The results of the contact angle measurement with water and the peel strength values of the hot pressed product with urethane rubber are shown in Table 1 below.

[0015]

[Table 1] However, in Table 1, the wettability index of (1) indicates a value measured with a wettability index standard solution. The contact angle of (2) is a contact angle with water and is a value measured by a goniometer. The peel strength of (3) was determined by cutting the treated ETFE tube into a film, hot-pressing it with a 1 mm thick urethane rubber at 200 ° C. for 1 minute at 1 kg / cm ² , and then cutting it into a 10 mm width to cut the ETFE tube. A 180 ° peel test between urethane rubbers was performed using a universal testing machine to determine the peel strength.

[0016]

As described in detail above, according to the present invention, the production process is relatively simple in a clean environment, and the adhesive strength with urethane rubber is sufficiently high for practical use.
It is possible to provide a surface modification method for a tube made of a fluororesin such as ETFE, which can be easily developed into a method for continuously modifying the surface of an FE tube.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a plasma processing apparatus according to the present invention.

FIG. 2 is an FT-IR chart of an untreated ETFE tube.

FIG. 3 is an FT-IR chart of an ETFE tube treated in an embodiment of the present invention.

[Explanation of symbols]

1 ... Reactor, 2 ... ETFE tube, 3 ... Tube set jig, 4 ... Piping, 5 ... Exhaust pipe,
6 ... Ring electrode, 7 ... Matching box, 8 ... High frequency power supply.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-166536 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08J 7/06 306

Claims (1)

(57) [Claims] 1. A method in which a tube made of a fluorine resin is disposed inside.
Reactor and a plasm attached to the outer periphery of the reactor.
Ring electrode for generating
Fluorine resin using a plasma device equipped with a high frequency power supply
This is a method for modifying the surface of a tube made of air , using air as a processing gas and an oscillation frequency of 13.56 MHz,
The plasma generated at a processing gas pressure of 0.02 to 1.5 Torr and a high frequency output of 25 to 200 W is used to generate
By treating in 60 seconds, the fluororesin tube
A method for modifying the surface of a fluororesin tube, characterized in that the outer peripheral surface of the tube is modified.