JPH05214138A - Molding having fluorine-containing surface - Google Patents

Abstract

PURPOSE:To modify the surface of a molding of hydrocarbon-based polymer without damaging characteristics of material by fluorinating the surface of the molding. CONSTITUTION:The surface of a molding is fluorinated in an organic solvent such as fluorocarbon in the presence of a peroxide as a reaction catalyst by using hexafluoroisobutene as a fluorinating agent. Since a fluorine component on the surface of the molding comprises -CF3 irrespective of the kind and shape of material, the surface is provided with characteristics such as water repellency, oil repellency, chemical resistance, weather resistance and antistatic properties while maintaining properties of material.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to surface modification of polymers. More specifically, on the surface of the hydrocarbon-based polymer molded product,
The surface is fluorinated by directly reacting hexafluoroisobutene. Repellent for the -CF ₃ can be imparted to the surface According to this method, lubricity, antistatic property, and further it is possible to obtain a molded article having excellent weather resistance.

[0002]

_2. Description of the Related Art Conventional methods for forming a fluorine-containing film on the surface of a polymer compound are roughly classified into direct fluorination with F ₂ gas (J. Appl. Polym. Sci.
19 , 1439 (1975). Plasma polymerization method by glow discharge (JP-A-55-993212 and JP-A-61-1332)
39 and others). Langmuir Brodget method (JP-A-62-62)
There are many known methods including a surface graft reaction method, a vacuum vapor deposition method, a sputtering method, and coating with a fluorine-containing silane coupling agent or a fluorine-containing resin.

A condition for producing a particularly durable thin film is that a chemical reaction between a film molecule and a base material is required.
Direct fluorination with ₂ gases, surface graft reaction, and plasma polymerization have been attracting attention.

In all of these methods, by introducing fluorine into the surface of the substrate, water and oil repellency, weather resistance, low refractive index property,
It is intended to improve low friction and chemical resistance. However, in the direct fluorination with F ₂ gas in addition to F ₂ gas itself is dangerous and may not be suitable in practical use, such as the substrate molecule is become brittle disadvantage is disconnected.

Further, the surface graft reaction has a drawback that it is difficult to provide a reaction site on the surface, and radiation or plasma is required for modifying a substrate having no reaction site. In addition, plasma polymerization has many merits and many studies have been carried out, but it is not suitable for a transparent material because it has a coloring problem such as yellowing of the film.

Further, according to these methods, there is a drawback that the adhesiveness and printability of the base material are remarkably deteriorated as the concentration of fluorine on the surface is increased, and it is not suitable for processing after the treatment.

[0007]

DISCLOSURE OF THE INVENTION The present inventors have aimed to form a fluorine-containing surface having a chemical bond on the surface of a hydrocarbon-based polymer molded article and without impairing the transparency of the substrate. As a result of repeated intensive studies, the present invention has been completed.

That is, the present invention provides that the use of hexafluoroisobutene _{(CF 3) 2 CH = CH} 2 the reaction agent, and it is possible to apply an effective -CF ₃ on the surface, based on order of a thin film of molecular order A uniform and strong fluorine-containing surface can be formed while maintaining the properties of the material.

Further, according to the present invention, since only CF ₃ can be applied to the surface, the treated substrate has a good water / oil repellency as compared with the case where hexafluoroacetone is used as the reaction agent. Is.

The present invention will be described in detail below. The hydrocarbon-based polymer molded article that can be used in the present invention may be one that can withstand the reaction temperature of hexafluoroisobutene (70 ° C. or higher), such as polyethylene, polypropylene, polystyrene, acrylic resin, polyester, polycarbonate,
Most general-purpose materials such as polyimide and vulcanized rubber can be used. The shape of the molded product is not particularly limited, and it can be a sheet or a fiber or a complicated shape.

The reaction agent of the present invention is hexafluoroisobutene and a peroxide having a hydrogen abstraction ability of the reaction catalyst. Examples of this peroxide include di-t-butyl peroxide, t-butyl cumiperoxide, dicumyl peroxide, α, α-bis (t-butylperoxy-m-isopropyl) benzene, and 2,5-dimethyl. −
2,5-di (t-butylperoxy) hexane and 2,5
-Diallyl peroxides such as dimethyl-2,5-di (t-butylperoxy) hexyl-3, 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane, 1,1- Bis (t-butylperoxy)
Peroxy such as cyclohexane, 2,2-bis (t-butylperoxy) octane, n-butyl 4,4-bis (t-butylperoxy) valerate and 2,2-bis (t-butylperoxy) butane Those that generate t-butoxy radicals represented by ketals are preferable.

The reaction temperature depends on the half-life of the peroxide used,
Although it can be arbitrarily selected in the range of 70 ° C to 180 ° C in view of the reaction rate, it is necessary to consider the deformation of the substrate, and it is preferably 70 ° C to 150 ° C.

The reaction time is appropriately determined depending on the half-life of the peroxide used and the reaction temperature, but is preferably 3
2 hours to 2 at a temperature of half-life to 10 hours half-life
4 hours will be adopted.

The reaction is carried out in a container capable of sealing hexafluoroisobutene by setting the above-mentioned reaction temperature and reaction time, but it is desirable to carry out in a suitable organic solvent in order to proceed the reaction mildly. Such an organic solvent is appropriately selected and determined depending on the solvent resistance of the substrate.

That is, as the organic solvent which can be used in the present invention, various kinds such as a chlorofluorocarbon type, a straight chain hydrocarbon, a ketone type and an ester type can be used, but the organic solvent having --OH, --NH ₂ etc. is hexafluoro. It cannot be used as it reacts directly with isobutene. Specifically, 1,1,2-trichloro-1,2,2-trifluoroethane, hexane, heptane, octane, acetone, methyl isobutyl ketone,
Ethyl acetate, propyl acetate, butyl acetate and the like can be mentioned.

When an organic solvent cannot be used due to the nature of the base material, the reaction catalyst may be attached to the surface of the base material for the reaction, and the reaction catalyst at this time may be diluted and applied. It can also be attached to the surface of the substrate by spraying, dipping or the like.

As described above, the fluorine content on the surface of the substrate can be controlled by adjusting various conditions such as the concentration of hexafluoroisobutene, the amount of reaction catalyst and the reaction time. The fluorinated concentration can be measured by the F / C elemental analysis value calculated by X-ray photoelectron spectrum (ESCA spectrum) analysis. The fluorination depth was below the measurement range of surface FT-IR, and it was found to be a very shallow region.

[0018]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Example 1 In a 100 cc stainless pressure vessel, 1,1,2-trichloro-1,2,2-trifluoroethane (40 cc) and di-
0.2 g of t-butyl peroxide, hot press film (100 μm) 2c of high density polyethylene as a base material
An m-square was charged and sealed and then deaerated. Then, 10 g of hexafluoroisobutene was charged in a liquid state, and the whole container was filled with 100 g.
The mixture was heated to ℃ and reacted for 24 hours. After the reaction, the polyethylene film was washed with 1,1,2-trichloro-1,2,2-trifluoroethane and vacuum dried at 40 ° C. for 2 hours. The polyethylene film thus obtained was designated as Sample A. Further, samples B and C were obtained in the same manner by changing the charged amount of di-t-butyl peroxide and the reaction time in the same manner.

Table 1 shows the reaction conditions and surface energies (critical surface tension: γ _c ) of samples A, B and C, and the fluorine content on the surface (F / C calculated from ESCA spectrum).

[0021]

[Table 1]

It can be seen from Table 1 that the critical surface tensions of the commercially available PTFE are almost the same. Example 2 Film surface treatment reactions of polyvinylidene fluoride, polycarbonate (bisphenol A type), and poly (ethylene terephthalate) were carried out in the same manner as in Example 1.

As the reaction catalyst, t-butylcumyl peroxide was used. The processed film (Sample D to
As the physical properties of I), the critical surface tension (γ _c ) and the fluorine content (F / C) were measured as in Example 1, and the results are shown in Table 2.

REFERENCE EXAMPLE The samples obtained in Examples 1 and 2 were reactions on the extreme surface, and qualitative state analysis of surface modification was impossible by infrared absorption spectrum. Therefore, the fluorination reaction was carried out in the form of fine powder using polycarbonate having a high reaction rate as a sample.

The reaction condition is t-similar to that of the sample G of Example 2.
Butyl cumyl peroxide 0.1 g, reaction temperature 130
The reaction time at 5 ° C. was 5 hours, and the polycarbonate used in the reaction was 1.0 g. After the reaction, the same treatment as in Example 1 was performed, and the infrared absorption spectrum was measured by the transmission method. According to this, --CF ₃ was found in the vicinity of 1300 cm ^-1 .

[0026]

[Table 2]

[0027]

EFFECTS OF THE INVENTION According to the present invention, it is possible to obtain a molded article having a fluorine-containing surface which has a uniform and strong adhesiveness and has a chemical bond with the surface of the substrate regardless of the type and shape of the substrate. You can

[0028] Since the fluorine component of the surface is made of -CF _3, it is possible to reduce the surface free energy in a small amount, the water and oil repellency of the surface while maintaining the properties of the molded article, weather resistance, a low refractive index And chemical resistance are achieved.

Claims (1)

[Claims] 1. Hexafluorocarbon is formed on the surface of a hydrocarbon-based polymer molded article.
Luoroisobutene, general formula (CF₃) ₂CH = CH₂Anti
Have a fluorine-containing surface characterized by reacting and modifying
Molded product.