JPS603334B2 - Polymer base material with fluorinated surface - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polymer base material in which only the surface of the base material has the characteristics of a fluororesin.

More specifically, the present invention relates to a polymer base material having a graft polymerization (copolymerization) layer formed from a fluorine-containing unsaturated monomer on the surface of the base material. Fluororesins have excellent properties brought about by fluorine atoms, such as stability, heat resistance, chemical resistance, low coefficient of friction, lubricity, non-adhesion, and biocompatibility.

On the other hand, fluororesin has poor mechanical strength and is opaque.
Due to the difficulty of melting and solution casting, there are problems such as the inability to form ultra-thin films. A particularly serious problem is that fluororesins are extremely expensive. By the way, many of the features of the fluororesin mentioned above are due to the surface characteristics of the fluororesin.

Therefore, if it is possible to provide a thin fluororesin layer on the surface of a resin other than fluororesin, it would be possible to create an inexpensive material that has excellent mechanical strength, transparency, and chemical resistance, is easy to slip, is non-adhesive, and is biocompatible. Polymer base materials can be obtained. Although the graft polymerization method itself is a known technique, no attempt has been made to graft polymerize a special substance such as a generating compound.
In other words, fluorine-based compounds are soluble in solvents, and it is unthinkable to polymerize them in a solution system.If possible, radiation polymerization would be possible, but such a polymerization method would deteriorate the base material itself, so it was not possible to polymerize it in a solution system. Graft polymerization of fluorine-based compounds has not yet been attempted industrially. The present inventors conducted intensive research to obtain such a polymeric base material, and as a result, they arrived at the present invention. That is, in the present invention, on the surface of the polymer base material, C=CHCOO
CH2(CF2)nCF2 days (n is an integer of 03n33)
, CH2=C(Cmelon)COOCH2(CF2)nCF2
day (n is 0 or 1), C ratio: CHCOOCH2CH2
(CF2) hCF2 days (n is 0 or 1), CH2=C
HCOOCH2 (CF2) nCF3 (n is an integer of 0 min n 4), C ratio = C (C general) COOCH2 (CF2) nC
F3 (n is an integer of 0 min n mi 2), CH2=CHCOOC
H2CH2 (CF2) nCF3 (n is an integer of 0 min 3), CH2 = C (CH3) COOCH2CH2CF3
This is a polymeric base material whose surface is made up of a discharge graft polymerization layer selected from the following.

The polymer base material here may be either a natural polymer or a synthetic polymer base material.

Such polymeric base materials include ordinary organic polymeric substances other than fluororesins, such as polyethylene, polypropylene, regenerated cellulose, diacetate, triacetate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polystyrene, polyester, polycarbonate,
Examples include polyvinyl acetate, polyurethane, polyimide, polyamide, polyphenylene oxide, polysulfone, polyacrylic ester, polymethacrylic ester, silicone rubber, mixtures thereof, and copolymers made of these monomers. . The polymer base material of the present invention has a block-like, plate-like, or film-like form.

The term "block shape" refers to a block of polymeric material, and its shape may be any shape such as a sphere, cube, rectangular parallelepiped, cylinder, or hollow body, and is not particularly limited.

The term "plate-shaped" refers to a rectangular parallelepiped with one side particularly shorter than the other two sides, and refers to the form of a polymeric material that is commonly called a plate or sheet. Film-like refers to the form of a polymeric substance that is a rectangular parallelepiped with one side that is extremely short compared to the other two sides, and whose thickness generally ranges from 1 to 300 mm, and generally refers to what is called a plastic film in the industry. . Discharge graft polymerization (copolymerization) as used in the present invention refers to exposing a base material to high voltage discharge in an active or inert gas to generate active sites on the surface of the base material, and then adding methyl methacrylate derivatives etc. to the base material. A graft polymerization (copolymerization) layer of the monomer is provided on the surface of the substrate by bringing it into contact with an unsaturated monomer.
The following three methods can be considered for the discharge graft polymerization method.

m This method is suitable for grafting monomers with high vapor pressure by exposing them to monomer vapor after activation by electric discharge. (2) This method is suitable for grafting monomers with low vapor pressure by exposing them to a monomer solution after activation by electrical discharge. '3} After activation by discharge, the substrate is heated to 02 or 02
This is a method in which the monomer is exposed to a gas containing , and then exposed to a heated monomer solution. In the present invention, any of the above-mentioned methods 1 to 3 may be used, and the method for producing the surface-fluorinated polymer base material of the present invention is not particularly limited.

However, judging from the research results of the present inventors, it can be said that the method of {11] is more preferable. It should be selected appropriately depending on various factors such as the type of gas, gas pressure, processing equipment, processing power source, and electrodes in the high voltage discharge that activates the surface.
It is not particularly limited.

In short, it is only necessary that the substrate to be treated be activated by high voltage (sustained voltage 200 to 500 V) discharge and that the fluorine-containing monomer be graft-polymerized. However, according to the findings of the present inventors, from the viewpoint of uniformity of activity and activation efficiency, gas pressure of 0.1 to
Treatment by low-pressure glow discharge of 20 mm Hg, more preferably 0.1 to 1 mm Hg, is more preferable. Examples of the inert gas used include Ar, He, and N2. Graft polymerization (copolymerization) of acrylic acid, methacrylic acid, methyl methacrylate, vinyl acetate, divinylbenzene, and 2-vinylpyrrolidone onto various substrates by discharge graft polymerization is already known, but the method of the present invention uses a fluorine-containing polymer. Qin unsaturated monomers can be easily discharge-grafted polymerized (copolymerized) to various polymeric base materials, and the base material with a thin graft polymerized layer formed like parentheses can be The specific fact that it has surface properties is not known. Note that the fluorine-containing unsaturated monomer may be used alone, or two or more types can be used simultaneously, and furthermore, the fluorine-containing unsaturated monomer and other monomers can be used simultaneously. A copolymerized graft polymer layer may be formed.

The graft polymerization layer made of a fluorine-containing compound on the surface-fluorinated polymer base material of the present invention can be provided on one side or both sides or in any pattern by selecting the side to be exposed to electric discharge. A thickness of about 2000A} can be formed. In the discharge graft polymerization method of the present invention, when the fluorine compound having a low vapor pressure is used, the polymerization treatment is carried out at a raised temperature, but the treatment is usually carried out at a temperature ranging from room temperature to the softening point of the base material. Next, some of the characteristics of the surface-treated polymer base material of the present invention will be listed.

'1} The surface of the base material is shark water and twill oil. {21 Non-adhesive. {3'Motomura's chemical resistance improves. '4
1. Easy to slip. '51 Transparency is improved compared to the original base material, and the depth of color is improved in the dyed base material. Usually, coating with fluororesin is performed to make polymeric base materials water repellent.
In this case, the surface characteristics of a fluororesin cannot be obtained unless a fluororesin layer with a thickness of several amperes or more is provided. This is interpreted to be because when the fluororesin layer is thin, a uniform resin layer is not formed on the surface of the polymer base material, and furthermore, fluorine atoms are not oriented on the surface. In contrast, in the present invention, the thickness is about 200 to 2000A, that is, 1/10 to 1/1 compared to coating.
With a thickness of 0.00 mm, properties unique to fluororesin can be realized, which was previously unimaginable.

Furthermore, the present invention has the following features.

'61 The mechanical properties of the base material are the same as those of the original base material, so they are significantly improved compared to the properties of fluororesin. Since the fluorine-containing resin layer on the surface is graft-polymerized to the base material, it will not be dissolved or washed away by solvents and is extremely durable. It is also possible to impart these properties only to limited surfaces of the original base material.

The present invention will be explained in more detail in the following examples.

Note that, as a matter of course, the present invention is not limited to the embodiments shown in these Examples. Example 1 A two-bag stretched polypropylene film "Torefan" (manufactured by Toray) with a thickness of 60 cm was stretched for 50 m using a 4 kW eye-excited oscillation type high frequency high voltage power supply in a gas atmosphere of 0.6 Hg. /
Discharge treatment was performed at a processing speed of min.

CH2:CHCOOCH2C was then generated at room temperature.
F2CF vapor was introduced into the apparatus and the electrical discharge treated substrate was exposed to the monomer for 5 minutes.

As a result of observing the total reflection infrared absorption spectrum of the film obtained in this way, it was found that 1755-1 was ester, 1
Strong characteristic absorption peaks due to fluoride were observed for 450 skin-1, 1240 skin-1, 840 arc-1, 77 skin-1, and 720 skin-1, indicating that the fluoride monomer was present on the polypropylene film surface. It was determined that the polymer had been subjected to discharge graft polymerization. Note that there is no absorption peak at this wave number in the infrared absorption spectrum of the polypropylene film. The film was placed in a Sotscray extractor and Freon 113 (C
An extraction operation was performed for 2 hours using C12FCCIF2 (trade name: Freon TF, manufactured by Mitsui Fluorochemicals) as an extraction solvent.

After that, the total reflection infrared absorption spectrum of this film was observed, and it was confirmed that there was almost no change in the characteristic absorption peak and its intensity compared to that of the film obtained by extracting grains. This confirmed that the fluorine-containing resin layer on the surface of the film was extremely durable. Comparative Example 1 In order to coat and laminate the C&=CHCOOCH2CF2CF2-day polymer onto a polypropylene film, the monomer was polymerized by a normal emulsion polymerization method, and then Freon 11
3 and dissolved in acetone.

However, the polymer only swells in these solvents and is not completely dissolved, making it difficult to coat and laminate the polymer onto the film. Example 2 A double-stretched polyethylene terephthalate film “Lumirror” (manufactured by Toray) with a thickness of 100 r was heated with N2 at 0.6 Hg.
Discharge treatment was performed at a processing speed of low/mjn using an intermittent oscillation type high frequency high voltage power source of water W under a gas fog area.

CH2=CHCOOCH2C was then generated at room temperature.
Steam was introduced into the apparatus, and the discharge-treated substrate was exposed to the monomer for 10 minutes. The film thus obtained had good transparency in the visible light region by about 4% compared to polyethylene terephthalate film.
In addition, the surface tension decreased to 31 dyne/arc compared to 44 dyne/arc of polyethylene terephthalate film,
It became more watery. Comparative Example 2 Asahi Guard AG-710, a Hiraha-based twill oil for textile processing
(manufactured by Asahi Glass Co., Ltd.) was diluted and dispersed with water and applied to a 2% aqueous solution using a bar coater on a 100 mm thick stretched polyethylene terephthalate film.
Dry for a minute.

The surface tension of the film thus obtained is 31 dyne'
Although it was below skin level, the fluorine resin coating easily dissolved and peeled off when water was dropped onto the surface.

This mirror orientation was also observed during surface tension measurement, making it difficult to accurately measure surface tension. Example 3 A 12 mm thick double-stretched polyethylene terephthalate film "Lumirror" (manufactured by Toray) was heated in an Ar gas atmosphere of 1 Hg using a small W eye excitation oscillation type high frequency high voltage 0 voltage power supply.
The discharge treatment was performed at a treatment speed of 20/mjn.

Next, CH2=CHCOOCH2C ratio CF2CF2CF8 vapor generated at room temperature was introduced into the apparatus, and the discharge-treated Motomura was exposed to the single enrichment body for ~5 minutes. The film thus obtained had a surface tension of 18 dyne/arc, and exhibited extremely good water and oil repellency.

Examples 4 to 22 In the same manner as in Example 3, the fluorine-containing monomers shown in Table 1 were subjected to discharge graft polymerization onto the biaxially oriented polyethylene terephthalate film "Lumirror".

The discharge treatment conditions and the exposure time to the fluorine-containing monomer were the same as in Example 3. When the surface tension of the discharge graft polymerized films was measured, as shown in Table 1, the surface tension decreased in all cases, and a value close to that of the fluorine-containing monomer polymer was obtained.

Table 1 Comparative Examples 3 and 4 In the same manner as in Example 3, a fluorine-containing monomer that is extremely easy to radically polymerize into double-stretched polyethylene terephthalate film "Lumirror" {1) CF2=CF2, ■C
F2=CFCI was subjected to discharge graft polymerization.

The discharge treatment conditions and the exposure time to the fluorine-containing monomer were the same as in Example 3. The surface tension of the discharge graft polymerized film is '1'CF2=CF2, 4 for the monomer.
0d skin e′伽■ CF2 = CFCI is significantly lower than the film with only 4 phantom e/arc and discharge treatment (65dy crotch/伽), but the untreated film (44dyne
/skin), only a slight decrease was observed compared to Example 1.
-22, the effect of discharge graft polymerization was significantly lower.

Claims (1)

[Claims] 1 On the surface of the polymer base material, CH_2=CHCOOCH_
2(CF_2)_nCF_2H (n is an integer of 0≦n≦3), CH_2=C(CH_3)COOCH_2(CF_
2)_nCF_2H (n is 0 or 1), CH_2=C
HCOOCH_2CH_2(CF_2)_nCF_2H
(n is 0 or 1), CH_2=CHCOOCH_2(
CF_2)_nCF_3 (n is an integer of 0≦n≦4), C
H_2=C(CH_3)COOCH_2(CF_2)_
nCF_3 (n is an integer of 0≦n≦2), CH_2=CH
COOCH_2CH_2(CF_2)_nCF_3(n
is an integer of 0≦n≦3), CH_2=C(CH_3)CO
A polymer base material whose surface is fluorinated and has a discharge graft polymerization layer selected from OCH_2CH_2CF_3.