JPS61166841A - Surface-treatment of fluorine-containing polymer - Google Patents

Abstract

PURPOSE:To carry out the surface-treatment of a fluorine-containing polymer to obtain a hydrophilic surface without deteriorating the characteristic properties of the polymer, by carrying out the plasma-polymerization of a mixture of a hydrocarbon compound having a double bond and oxygen in the presence of a fluorine-containing polymer. CONSTITUTION:Plasma-polymerization of a mixture of a hydrocarbon having a double bond (preferably ethylene, propylene, etc.) and oxygen (the molar ratio of hydrocarbon/oxygen is 0.1-10, preferably 0.2-4) is carried out in the presence of a fluorine-containing polymer (e.g. a homopolymer or copolymer of tetrafluoroethylene, a polymer obtained by the plasma fluorination of the surface of a polymer free from fluorine), at a discharge power controlled to give an electron temperature of preferably 5,000-80,000 deg.C. A thin film of a plasma polymer is formed on the surface of the fluorine-containing polymer by this process.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides surface treatment for making the surface of a trifluoropolymer hydrophilic using a plasma polymerization method without impairing the excellent properties of the fluoropolymer. It is about the method.

[Conventional technology]

Fluoropolymers have extremely high resistance to water absorption, oil, and staining, and are widely used in fields that require these properties, especially in recent years. In view of their excellent resistance to water absorption, oil injection, and staining, the use of fluoropolymers as medical materials, such as materials for contact lenses and intraocular lenses, is being considered. .

Medical materials using fluorine-containing polymers are lipids because the fluorine-containing polymers have excellent water absorption resistance, oil resistance, and stain resistance as described above.

It is a preferable material because it is less likely to cause stains due to adsorption or absorption of biological components such as proteins (on the other hand, it is poorly compatible with biological fluids due to its low hydrophilicity, and
For example, when such a fluoropolymer is used as a detergent for contact lenses or intraocular lenses, the fluoropolymer and lachrymal fluid, aqueous humor, etc. Since these lenses are poorly compatible with biological fluids, problems arise such as the inability to obtain a good feeling when wearing these lenses. Therefore, in order to solve such problems, it is necessary to modify the surface of the fluoropolymer to make it hydrophilic.

Modification methods for making the surface of a polymer hydrophilic include, for example, a method in which the polymer is immersed in a strongly oxidizing solution; 1 a method in which the polymer is photooxidized by irradiation with ultraviolet rays;

A method of treating a polymer with oxygen plasma or the like is known. However, when these methods are applied to the surface treatment of trifluoropolymer, the effect of surface treatment is temporary and its change over time is large (i.e., hydrophilicity rapidly loses over time). -I have a problem.

[Problem that the invention seeks to solve]

The present invention solves the problem of conventional modification methods, such as large changes over time after surface treatment, as described above, and improves fluorine-containing polymers without impairing their excellent properties. Is there a method for surface treatment of fluoropolymers that imparts good hydrophilicity to the surface of the polymer and that hydrophilicity does not easily change over time? The purpose is to provide.

[Means for solving problems]

In the present invention, plasma polymerization is performed using a specific mixed gas containing a hydrocarbon compound having a double bond and oxygen in the presence of a substrate made of a fluoropolymer to be treated, thereby treating the surface of the substrate. A thin film made of plasma polymer (hereinafter referred to as "plasma polymer film")'! ! −
By integrally forming the substrate, the surface of the substrate made of the fluoropolymer can be made hydrophilic without impairing the excellent properties of the fluoropolymer.

Examples of the hydrocarbon in the present invention include compounds represented by the following general formula (A).

(In the formula, % 1 * R2 is the same or different, and consists of an alkyl group such as a methyl group, an ethyl group, a propyl group, an alkenyl group such as a vinyl group, a propenyl group, an allyl group, and a hydrogen atom. Examples of the compound represented by the above general formula (A) include ethylene, propylene, 2-butene, inbutylene, 2-
Methyl-2-butene, 2,3-dimethyl-2-butene, 1-butene, 3-hexene%2-ethyl-1-butene, 3-ethyl-3-hexene, 3,4-diethyl-3
-hexene, 1,3-butadiene, 1e, 3,5-hexatriene, 2-vinyl-1,3-butadiene%3-vinyl-1,3゜5-hexatriene, 3,4-divinyl-1,3゜5-Hexatriene% 2-pentene, 2-
Methyl-1-butene, 2,3-dimethyl-2-pentene, 3-methyl-3-hexene, 3-ethyl-2-pentene, 3-methyl-4-ethyl-3-hexene.

2-Methyl-3-ethyl-2-pentene, 2,3-dimethyl-3-hexene, isoprene, 1,3-pentadiene, 3-methyl-1,3-pentadiene%4-)f-1,3-pentadiene %3.4-dimethyl-1,3-pentadiene, 3-)f-xt3e5-hexatriene%3-vinyl-1°3-pentadiene, 3-methyl-4
-vinyl-1,3,5-hexatriene, 3-vinyl-
4-Methyl-1,3-pentadiene, 394-dimethyl-1,3,5-hexatriene, 1,3-hexadiene, 2-ethyl-1,3-butadiene, 3-ethyl-1,
3-hexadiene, 4-ethyl-1,3-hexadiene%3.4-diethyl-1゜3-hexadiene, 3-vinyl-1,3-hexadiene, 3-ethyl-1,3,5-
Hexatriene% 3-ethyl-4-vinyl-1,3,5
-hexatriene, 3,4-diethyl-1,3,5-hexatriene, a-vinyl-4-ethyl-1,3-hexadiene, 3-methyl-1,3-hexadiene, 4-)
f-1,3-hexadiene%3-ethyl-1,3-pentadiene, 3-ethyl-4-methyl-1,3-pentadiene, 3,4-dimethyl-1,3-hexadiene, 3
-Methyl-4-ethyl-1,3-hexadiene, 3-ethyl-4-methyl 1,3-hexadiene, 3-methyl-4-ethyl-1,3,5-hexatriene, 3-vinyl- Examples include 4-methyl-1,3-hexadiene, 1,4-pentadiene, etc., and preferably ethylene, propylene, l,3-butadiene, l-butene, 2
-butene or isobutylene. Other examples of hydrocarbons in the present invention include cyclic hydrocarbon compounds containing double bonds.

U, uJ as a cyclic hydrocarbon compound containing the above double bond
, t, benzene, toluene, ethylbenzene, propylbenzene, cumene, butylbenzene, xylene, ethyltoluene, cymene, diethylbenzene, trimethylbenzene, tetramethylbenzene, styrene, methylstyrene, allylbenzene, divinylbenzene% 1-phenyl-1 , 3-phtadiene, biphenyl, 1e2-')
Aromatic hydrocarbons such as phenylethane, cyclopentene, cyclopentadiene, fulpene, cyclohexene.

Alicyclic hydrocarbons such as methylcyclohexene, cyclohexadiene, cyclobutene, cyclooctatetraene, mente-limonene, di-pentene, terpinolene, terpenene, phelandrene, sylvestrene, carene, pinene, bornene, pentalene, indene, naphthalene, etc. fused polycyclic hydrocarbon, bicyclo-(2゜2.1)-2
- Hydrocarbons such as heptene, spiro-(4,5)
-1゜6-decacien, spiro(cyclopentane-1
Spirocyclic hydrocarbons such as ゜1'-indene) can be mentioned, and fL< is preferably benzene and styrene.

They are toluene, ethylbenzene, xylene, ethyltoluene, diethylbenzene and methylstyrene.

These compounds are plasma polymerizable substances that can be gasified in a plasma polymerization system.

In addition, these compounds can be used in combination, and in the Oyagi invention, they are mixed with a hydrocarbon RA11 element in plasma polymerization,
This mixed gas is characterized by being completely surrounded by, for example, hydrogen, -carbon oxide.

An inorganic gas such as carbon dioxide, water vapor, nitrogen, argon, helical xenon, or neon can be added in an amount of about 20 mol or less.

The mixing ratio of hydrocarbon and oxygen (hydrocarbon/oxygen) is usually 0.1 to 10. Preferably it is 0.2 to 6 degrees, more preferably 0.2 to 4 degrees. If this mixing ratio is less than 0.1, the production rate of the plasma polymer film will be slow by 1, making it impractical, and the durability of the plasma polymer film performance will be poor (
Moreover, if it exceeds 10 t, the hydrophilicity of the plasma polymer film is insufficient, and at the same time, there are places where the hydrophilicity is insufficient locally.

The fluoropolymer used in the present invention includes:

If kept, tetrafluoroethylene, fluorovinylidene,
Homopolymers and copolymers of fluorine-containing monomers such as fluoroalkyl acrylate, fluoroalkyl methacrylate, fluoroketone, fluorovinyl ether,
Copolymers of fluorine-containing monomers such as tetrafluoroethylene and propylene, fluoroalkyl acrylates, fluoroalkyl methacrylates and alkyl acrylates or alkyl methacrylates, and non-fluorine-containing monomers, fluorine-containing tetrabasic acid dianhydrides and fluorine-containing dianhydrides Examples include polymers obtained by reacting fluorine-containing diisocyanates with diamines, polymers obtained by reacting fluorine-containing diisocyanates with polyalkylene glycols, and diamines, and fluorine-containing silicone polymers such as methyl triple opropyl siloxane. These polymers are not limited to
jj Additives such as II agents and stabilizers may be added◎ Furthermore, the fluorine-containing polymer used in the present invention includes polymethyl methacrylate, polycarbonate, polystyrene,
Tetrafluoromethane, hexafluoroethane, or
Fluorine-containing compounds such as tetrafluoroethylene, octafluoropropane, perfluoromethylcyclohexane, perfluorotoluene, mixtures thereof, or mixtures of these with hydrocarbons such as methane to form plasma polymer films, nitrogen fluoride, and fluorine-containing compounds. boron oxide,
Fluorine-free polymers such as fluorinated silanes can be used to produce fluorine-free polymers that have been fluorinated by plasma treatment. The combined surface may be fluorinated, or the surface of a polymer that does not contain fluorine may be coated with a fluorine-containing polymer @ Conditions for plasma polymerization in the present invention, such as the degree of vacuum in the reaction vessel, and the mixing specified separately. The gas flow rate, discharge power, etc. are the same as those for normal plasma polymerization.
There are no particular limitations, but for example, the degree of vacuum in the reaction vessel is 1 mm to 10 Torr, and the flow rate of the mixed gas as described in JJI is 1 in standard conditions if the capacity of the reaction vessel is 50 or more. 0.1~100cc per minute (STP)
t - can be mentioned @Also, the discharge power is ttI so that the electron temperature of the plasma is 5,000 to 80,000 degrees.
It is preferable to use 4t. In addition, the electron temperature is based on Japanese Patent Application Laid-open No. 1983
The information can be obtained by the method described in Japanese Patent No. 135574. If the electron temperature is less than 5,000 degrees, the formation rate of the plasma polymer film is slow, making it impractical; if it exceeds 80,000 degrees, the hydrophilicity of the surface of the fluoropolymer becomes uneven depending on the location, and Durability also becomes poorer. even higher
In order to impart durability to the gold plasma polymer film, the discharge power is adjusted so that the electron temperature is between 5,000 and 60,000 degrees.
The plasma polymerization time varies depending on the thickness of the plasma polymer film to be formed on the fluoropolymer. The thickness of the plasma polymer film is not particularly limited, but is usually 1.
As long as the thickness is about ~5000λ, the plasma polymerization time is therefore short, for example, several tens of minutes or less. The equipment used for plasma polymerization is 1. A coil 2 is provided at the small diameter part of one end of the reaction vessel 1 connected to the oscilloscope (not shown), and a frequency power source 3t- is connected to the coil 2.
A substrate St made of a fluorine-containing polymer to be treated is held on a support stand 4 inside the reaction vessel 1 while the inside of the reaction vessel 1 is evacuated.

A mixed gas of hydrocarbons and oxygen is introduced into the reaction vessel 1 through the gas inlet 5, and a full frequency voltage is applied to the coil 2 to generate plasma in the reaction vessel 1. Plasma is applied to the outer surface of the substrate S made of the fluorine-containing polymer to form a plasma polymer film thereon.

Alternatively, as shown in FIG.
．． A substrate St made of a fluorine-containing polymer to be treated is held between the electrodes 11' and an AC power supply 12i is connected between the electrodes 11 and 11', thereby generating plasma between the north poles 11 and 11'. urge

This plasma t is applied to the outer surface of the substrate S to form a plasma polymer film thereon due to the mixture of hydrocarbons and oxygen. Note that 13 is an exhaust pipe, and 14% 14' is a reaction gas introduction pipe.

In addition, the apparatus for plasma polymerization is not limited to those shown in FIGS. Good too. In the case of alternating current, low frequency, -frequency,
It may be of any microwave frequency. Here, what is the coupling method between the amplifier and the plasma system in the case of microwaves?

Either a ladder type or cavity type may be used.

Furthermore, the type of electrode for plasma generation, that is, the induction type.

Regarding capacity type, there are no restrictions on 1kv.
h@ [Examples] Examples of the present invention will be described below, but the present invention is not limited thereto.

Example 1 A contact lens and a disc (thickness 1 mm *diameter 15 mm) made of a methyl) ester-perfluoroalkylethyl methacrylate copolymer were placed on a support stand using the reaction vessel shown in FIG. 2. ethylene (flow rate 10 cc (STP)/m1n) and oxygen (A! 10
While introducing a mixed gas with cc(STP)/win) into the reaction vessel and maintaining a vacuum level of 50 mTorr in the vessel, 10 KHz AC power was applied to tm, and the electron temperature was 2.5. A plasma polymerization time of ±0.3 million degrees was allowed to react for 10 minutes to form a plasma polymer on the surface of the contact lens and disk. The test was conducted on 10 Fi samples of contact lenses (the same applies to the following Examples and Comparative Examples).

Regarding the contact lenses having the plasma polymer film obtained above, the following five items (1) to (5) are explained.
1. Regarding the disk, take the L1 Note Exam for one item in (6) @
I did everything. The results are shown in Table 1.

In addition, in the characteristic test of contact lenses, the corresponding number of 10 samples is expressed as at.

(1) Removal of oil and other stains: After soaking a dry contact lens in water for 5 seconds, apply cold cream to the contact lens, place the contact lens between your thumb and index finger, and immerse it in water. After washing, it was taken out into the air and observed for water droplet adhesion. As a result, it was determined that there is no oil content and that sticks well to water.

(2) Oyaki note: After soaking a dry contact lens in water for 5 seconds, it was taken out into the air and the state of water droplet adhesion on each contact lens was observed. As a result, the entire surface of the lens was wetted with water (those that got wet were marked as "×" and those where the surface of the lenses repelled water were marked as "x".

0) Good visibility when wearing contact lenses: Evaluate whether the visibility worsens when wearing contact lenses. 1. Those with good visibility t-a%. Those that are cloudy. Movement Note: When wearing contact lenses, we evaluated whether they moved when blinking, and rated 1 for those that moved moderately, and rated x for those that did not move easily.

6) Surface durability: A contact lens was placed between the gold thumb and the eighth finger and rubbed 2,000 times in water, then taken out into the air and the state of water droplet adhesion on each contact lens was observed. As a result, the entire lens surface was wetted with water (tQ was wetted, and × was the lens surface that repelled water.) (6) Change in contact angle over time For two circular sheet metals, the contact angle of water over time Comparison column 1 Using contact lenses and discs made of methyl methacrylate-perfluoroalkyl ethyl methacrylate copolymer without surface treatment by plasma polymerization,
All characteristic tests similar to those in Example 1 were performed. The results are shown in Table 1.

Example 2 Same as Example 1 except that the molar ratio of ethylene and oxygen was changed to 4.

9. Perform plasma 1 in the same manner as in Example 1 to perform surface treatment of the conotact lens and disc. Characteristic tests similar to those in Example 1 were conducted on the obtained conotact lenses and discs. The results are shown in Table 1.

Comparative Example 2 First, only ethylene was used as the gas component without using [X, and the ethylene flow rate was set to 15 cc (STP)/min.
, except that plasma polymerization was carried out in the same manner as in Example 1, and then acid x<v' was added as a gas component in an amount of 10 cc.
The same plasma polymerization was performed again using only (STP )/min, ) to perform surface treatment of contact lenses and discs. Custom tests similar to those in Example 1 were conducted on the resulting contact lenses and discs. The results are shown in Table 1.

Example 8 In Example 1, except that 1-butene was used as a substitute for ethylene and the mixing ratio of 1-butene and powder (l-butene/m element) was set to 1.0 in terms of molar ratio, Compensation? Plasma polymerization was performed in the same manner as in No. 111, and the surfaces of the conotact lens and disk were treated. Characteristic tests similar to those in Example 1 were conducted on the obtained contact lenses and discs. The results are shown in Table 1.

Example 4 In Example 1, benzene was used in place of ethylene, and the molar ratio of ben and oxygen was 1.
Plasma X treatment was carried out in the same manner as in Example 1, except that the temperature was 0.0, and the surfaces of the conotact lens and disk were treated. A custom test similar to that in Example 1 was conducted on the obtained conotact lenses and discs. The results are shown in Table 1.

Example 5 Using the reaction vessel shown in Fig. 2, a conotact lens made of dimethylpolysiloxane and a circular &t
)/min, ) in the reaction vessel, while maintaining the vacuum of 50mm and 1JTorr in the vessel, generate a plasma by applying toKHz power to the electric lamp, and leave it for 20 minutes. The reaction was carried out over a period of time to completely form a fluorine-containing plasma polymer film on the surfaces of the contact lens and disc. Thereafter, the contact lens and disk were all taken out from the reaction vessel, washed with water, dried, and then held again on the support in the reaction vessel, and subjected to surface treatment by plasma polymerization in the same manner as in Example 1. Characteristic tests similar to those in Example 1 were conducted on the obtained contact lenses and disks.Results 1-, O shown in Table 1.As is clear from the above results, in Example 1 of the present invention. Good results were obtained throughout the characteristic tests. On the other hand, in Comparative Example 1, the surface of the fluoropolymer was not subjected to surface treatment by plasma polymerization, so although the removability of oil and other stains was good, the hydrophilicity was insufficient and contact It can be seen that the lens is inferior in the water wettability required of a lens and the condition of use 1 when worn, and is poor in practicality. In addition, in Comparative Example 2, the surface treatment by plasma polymerization was performed in succession in each individual gas atmosphere without mixing hydrocarbon and oxygen. Although it gets wet with water, it loses its hydrophilicity over time and not only deteriorates significantly over time, but also has poor surface durability.
It can be seen that this is not practical.

〔Effect of the invention〕

According to the present invention, as is clear from the results of the above-mentioned examples, plasma polymerization is carried out using a specific mixed gas containing a hydrocarbon and oxygen in the presence of a substrate made of a fluoropolymer to be treated. By forming a plasma polymer film on the surface of the substrate material, the surface of the fluoropolymer can be easily modified, and a material Ht having the following properties can be provided.

(1) The surface is made of plasma polymer.

Has poor water wettability.

(2) The above-mentioned plasma polymer is chemically stable and its hydrophilicity does not decrease over time (<, therefore, it can maintain good water wettability over a long period of time.

Q) The above plasma polymer is excellent in terms of mechanical strength, friction resistance, etc., and therefore has excellent durability t-4.

(4) Without impairing the excellent properties of the fluoropolymer, such as water absorption resistance, oil resistance, and dirt resistance.

Having the properties (1) to (3) above, the material obtained by the method for surface treatment of a fluoropolymer of the present invention has the excellent properties essentially possessed by the fluoropolymer and the material according to the present invention. It has the excellent properties of the plasma polymer membrane in , for example, it has good compatibility with biological fluids, and it is difficult to absorb or absorb oily substances such as lipids in biological fluids, making it difficult to be contaminated. It can be preferably used for medical materials that particularly require the following conditions.

In addition, as a stain-proofing method for fibers, there is a known method of coating the fiber surface with a fluorine-containing monomer, but although such a method makes it difficult for stains to penetrate inside the fiber,
r(h) Once a layer of dirt has formed, especially oil-based dirt, it becomes difficult to remove it in washing water. However, following this method, the present invention is applied to make the surface hydrophilic, thereby removing dirt. ) Since removal becomes easy, the present invention is also effective as a method for surface treatment of fibers.

[Brief explanation of the drawing]

1 and 2 show examples of apparatuses used in the plasma polymerization treatment method of the present invention; FIG. 1 shows a discharge tube type apparatus, and FIG. 2 shows a Pelger type apparatus. 1... Reaction container 2... Coil 3.12...
・Power source 4... Support stand 5... Gas population
10... Reaction container (Perger type) 11.11'.
...Electrode 13-...Exhaust pipe 14.14'--Reaction gas introduction pipe Agent Patent attorney Masahiko Oi Pa'h・,-ノ'

Claims (1)

[Claims] 1) A fluorine-containing polymer characterized in that a thin film of a plasma polymer is formed on the surface of the fluorine-containing polymer by performing plasma polymerization using a mixed gas containing a hydrocarbon compound having a double bond and oxygen. Coalescence surface treatment method.