JP2707597B2 - Method for producing fluorine-containing polyolefin - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a fluorinated polyolefin having excellent water and oil repellency and hydrolysis resistance.

[Conventional technology]

Polyolefins have a good balance of various physical properties, and are inexpensive and have good processability.
It is used for a wide range of applications such as fiber. However, since polyolefins have basically the same chemical structure as aliphatic hydrocarbons, they have the drawback that oil easily adheres and the adhered oil is difficult to remove.

On the other hand, fluororesins such as polytetrafluoroethylene (PTFE) exhibit excellent water and oil repellency due to their extremely low surface free energy, and have the advantage that oil does not easily adhere, but are inferior in moldability and extremely expensive. There is a disadvantage that it is.

Attempts have been made to introduce fluorine into the polyolefin to impart water and oil repellency comparable to that of PTFE. For example, Polymer Letters Edition Vol. 12, p.177-187 (197
4) proposes a method of fluorinating a resin powder such as polyethylene or polystyrene under a stream of fluorine gas. However, direct fluorination with fluorine gas has a remarkably high heat of reaction and difficult to control the reaction, so that it is very difficult to mass-produce it.

Japanese Patent Publication No. 47-19697 proposes a method in which polyethylene is irradiated with radiation and then grafted with tetrafluoroethylene. However, this method is also unsuitable as an industrial mass production method because of limitations in equipment.

JP-A-61-23616 proposes a method of grafting an acrylate having a perfluoroalkyl group to a polyolefin. However, the product obtained by this method is chemically unstable due to the presence of an ester bond between the polyolefin and the perfluoroalkyl group. Inevitable.

[Problems to be solved by the invention]

An object of the present invention is to solve the above problems by efficiently producing a fluorine-containing polyolefin having excellent water repellency, oil repellency and hydrolysis resistance by a mass production method which was extremely difficult with the conventional method. The present invention proposes a method for producing a fluorine-containing polyolefin, which is possible.

[Means for solving the problem]

The present invention relates to a polyolefin and a fluorine-containing olefin compound having no ester bond in an amount of 1 to 1000% by weight based on the polyolefin.
Solvent for dissolving raw polyolefin in the presence of a radical initiator and an olefin compound having 2 to 20 carbon atoms and 1 to 40 fluorine atoms, which is composed of fluorine and, if necessary, hydrogen and / or another halogen atom A method for producing a fluorinated polyolefin having excellent water and oil repellency and hydrolysis resistance, characterized by reacting and grafting in the presence of olefin.

The polyolefin used as a raw material in the present invention is a homopolymer or a copolymer of an olefin monomer. Examples of the olefin monomer include ethylene,
Propylene, 1-butene, cis-2-butene, trans-2-butene, isobutylene, 4-methyl-1-butene, 1-pentene, 3,3-dimethyl-1-butene, 4-
Methyl-1-pentene, 3-methyl-1-pentene, 1
-Hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 1-hexadecene,
-Eikosen or the like. The molecular weight of these polyolefins is not particularly limited. For example, a wide range of polyolefins having a weight average molecular weight of about 300 to 1,000,000 or more can be used. For example, in the case of polyethylene, from a wax grade having a weight average molecular weight (w) of about 1,000 to 8000, a general injection molding, hollow molding, extrusion molding, film and fiber grade of w 10,000 to 300,000, and a w 1,000,000 or more Any of the ultra-high molecular weight grades can be used.

When reacting a fluorine-containing olefin compound with a polyolefin according to the method of the present invention, depending on the type of the polyolefin, cutting off the polyolefin main chain, side reactions such as recombination may occur simultaneously, and the molecular weight distribution of the polyolefin may change, Even in this case, the object of the present invention of introducing fluorine into the polyolefin is achieved, and the usefulness of the produced fluorine-containing polyolefin is not lost at all.

Next, the fluorine-containing olefin compound used as another raw material in the present invention is an olefin compound having no ester bond in its molecule. Here, it is important not to contain an ester bond.For example, when a fluorine-containing acrylate or a fluorine-containing methacrylate is used, the fluorine-containing polyolefin produced by the grafting undergoes hydrolysis, so that the fluorine-containing group introduced by the grafting is There is a problem of detachment, which is not preferable. That is, the fluorine-containing olefin compound used in the present invention does not contain an ester bond, and is composed of carbon, fluorine and, if necessary, hydrogen and / or another halogen, and has 2 to 20 carbon atoms and a fluorine atom. Fluorine-containing olefin compounds of numbers 1 to 40 can be used.

Illustrative examples of the fluorinated olefin compound include tetrafluoroethylene, trifluoroethylene, vinylidene fluoride, vinyl fluoride, monochlorotrifluoroethylene, 1-chloro-2,2-difluoroethylene and 1,1-dichloro-2. , 2-difluoroethylene, vinylidene chlorofluoride, hexafluoropropene, 3,3,3,2-tetrafluoropropene, trifluoromethylethylene,
-Fluoropropene, 2-chloro-1,1,3,3,3-pentafluoropropene, 1,1,2-trichloro-3-trifluoropropene, perfluoro-1-butene, perfluoro-1-pentene, Perfluorobutylethylene, perfluoro-1-heptene, perfluoro-1-nonene,
8-H-perfluoro-1-octene, perfluorohexylethylene, perfluorooctylethylene, perfluorodecylethylene, perfluorododecylethylene and the like.

In order to sufficiently exhibit the water and oil repellency of the fluorinated polyolefin produced by the present invention, it is necessary to react the fluorinated olefin compound with the raw material polyolefin in an amount of 1 to 1000% by weight, particularly 10 to 500% by weight. It is desirable to use.

In the present invention, a fluorine-containing polyolefin is produced by generating a radical on the raw material polyolefin and reacting the radical with the fluorine-containing olefin compound. It is performed by a method of adding a radical initiator such as a system compound. As another method for generating radicals, there is a method of irradiating radiation such as X-rays and γ-rays. However, at present, a radiation generator adapted for industrial mass production cannot be incident. On the other hand, according to the method using the radical initiator of the present invention, industrial production can be easily performed in a commonly used reaction vessel without requiring a special device.

Specific examples of the radical initiator that can be used in the present invention include, as a peroxide, isobutyryl peroxide,
2,4-dichlorobenzoyl peroxide, t-butylperoxypivalate, benzoyl peroxide, cyclohexanone peroxide, dicumyl peroxide, di-
As azobis-based compounds such as t-butyl peroxide and citrate hydroperoxide, 2,2′-azobisisobutyronitrile, 2,2′-azobisisobutylamide,
Methyl 2'-azobis-2-methylpropionate, 2,2 '
-Azobis-2-methylbutyronitrile, 1,1'-azobiscyclohexanenitrile, 4-nitrophenylazobenzylcyanoacetic acid and the like. It is usually sufficient to use these radical initiators in an amount of 0.01 to 10% by weight based on the raw material polyolefin.

In the method for producing a fluorinated polyolefin of the present invention, the reaction can be performed at a low pressure by reacting in the presence of these radical initiators and in the presence of a solvent. In this case, the solvent is not particularly limited as long as it basically dissolves the raw material polyolefin and hardly causes radical chain transfer. Specific examples of usable solvents include benzene, toluene, xylene, chlorobenzene, dichlorobenzene, dichloromethane, carbon tetrachloride,
Examples include dichloroethane, benzotrifluoride, xylene hexafluoride and the like. In particular, when a fluorine-containing solvent such as benzotrifluoride and xylene hexafluoride is used, there is an advantage that the reaction efficiency between the polyolefin and the fluorine-containing olefin can be further increased.

When an aliphatic hydrocarbon-based or ether-based solvent is used, the addition reaction of the fluorinated olefin to the solvent cannot be neglected, so that it is preferable to avoid using these solvents. The reaction temperature, reaction pressure, reaction time, etc. are not particularly limited, but the reaction can be carried out at a low temperature and a low pressure, taking into account the half-life of the radical initiator used, the solubility of the raw material polyolefin in the solvent, and the like. Then, just set reasonable conditions.

The reaction apparatus can be used without any particular limitation, such as a very common reaction vessel. When the reaction is performed at a temperature equal to or higher than the boiling point of the fluorine-containing olefin, a pressure-resistant device can be used.

The method of charging the reaction raw materials and the like is not particularly limited. For example, a method of charging a polyolefin, a fluorine-containing olefin compound, a radical initiator, a solvent, and the like all at once, or a method of adding only the radical initiator later or collectively in a divided manner , Various methods can be selected.

In the above production method, when a solvent is used, and when an unreacted fluorinated olefin compound remains after the reaction, the reaction product is subjected to a treatment such as decompression or heating, and the solvent or the fluorinated olefin is purged. By doing so, a fluorinated polyolefin can be obtained. Alternatively, a method in which the reaction product is dissolved in a good solvent, and then poured into a poor solvent to reprecipitate the fluorinated polyolefin, separated and dried.

Examples of good solvents include decalin, tetralin, cyclohexane, saturated and unsaturated hydrocarbons such as hexane, benzene, toluene, xylene, chlorobenzene,
Examples thereof include various aromatic hydrocarbons such as dichlorobenzene, benzotrifluoride, and xylene hexafluoride and derivatives thereof, chlorinated hydrocarbons such as carbon tetrachloride, dichloromethane, dichloroethane, and carbon disulfide. Examples of the poor solvent include alcohols such as methanol, ethanol, and n-propanol, and acetone and ether.

By reacting the polyolefin and the fluorinated olefin compound as described above, the fluorinated olefin compound is grafted on the polyolefin, and a fluorinated polyolefin is produced.

The fluorinated polyolefin thus produced has a high fluorine content, is excellent in water / oil repellency and hydrolysis resistance, and is used for molded articles, films, fibers, and the like.
It can be used as a modifier for imparting water / oil repellency by adding another resin.

That is, the fluorine-containing polyolefin obtained by the present invention has various characteristics of fluorine such as water and oil repellency, low friction, lubricity, solvent resistance, chemical resistance, low refractive index, non-adhesion, low dielectric constant, It can be used in various applications as a material having radiation functionality, oxygen permeability, etc., and has high hydrolysis resistance. Also, while conventional fluororesins were hardly compatible with other resins, the fluorinated polyolefins of the present invention can be easily blended with, for example, ordinary polyolefins, etc. Because it can be used, it can be used as a resin modifier.

〔The invention's effect〕

As described above, according to the present invention, a fluorine-containing polyolefin having a high fluorine content and excellent in water / oil repellency and hydrolysis resistance can be efficiently produced at a low pressure, and production by a mass production method is also possible. is there.

〔Example〕

Hereinafter, examples and application examples of the present invention will be described.

Example 1 A low molecular weight polyethylene wax (A) (melting point of 118 ° C., density
0.95 / cm ³ , molecular weight 900) 4.5 g, chlorobenzene 60 g as a solvent, and benzoyl peroxide (BPO) 300 mg as a radical initiator were charged. After the inside of the system was replaced with nitrogen, hexafluoropropylene 19.5 was used as a fluorine-containing olefin compound.
g was charged and reacted at 100 ° C. for 10 hours with stirring. After cooling to room temperature, unreacted hexafluoropropylene was purged, and then most of the solvent was distilled off by an evaporator. Finally, the mixture was heated and stirred at 120 ° C. for 5 hours under a reduced pressure of 1 mmHg to remove volatile components, thereby obtaining 5.1 g of a fluorine-containing polyethylene wax. After the sample was burned in an oxygen bottle, the F anion was determined by ion chromatography to determine the F content, which was 9.8 wt%. Also,
The melting point of this sample measured using a differential scanning calorimeter (DSC Model 20 manufactured by Seiko Instruments Inc.) was 113 ° C.

Examples 2 to 20 In the same manner as described below, fluorine-containing polyolefins were synthesized by changing the amounts and types of the raw material polyolefin, the fluorine-containing olefin compound, the solvent, and the radical initiator.

Table 1 summarizes the above results. The details of the various raw materials are as follows.

Ethylene-propylene wax (B): synthesized by copolymerizing 96 mol% of ethylene and 4 mol% of propylene with a Ziegler catalyst. 115 ° C, molecular weight 7,0
00 High-density polyethylene (C): MI (melt index) at 190 ° C and 2.16 kg = 1
4 g / 10 min, density 0.965 g / cm ³ , melting point 133 ° C. High density polyethylene (D): MI at 190 ° C., 2.16 kg = 0.45 g / 10 min, density 0.96 g /
cm ³ , melting point 137 ° C polypropylene (E): MI at 230 ° C, 2.16 kg = 1.0 g / 10 min, density 0.910 g /
cm ³ , melting point 164 ° C. Poly-4-methyl-1-pentene (F): 260 ° C., MI at 5 kg = 26 g / 10 min, density 0.833 g / c
m ³ , melting point 234 ° C. Poly-1-butene (G): MI at 190 ° C., 2.16 kg = 0.03 g / 10 min, density 0.915 /
cm ³ , melting point 121 ° C. Hoe S-3196: Perfluoroalkylethylene (trademark) manufactured by Hoechst RfCH = CH ₂ Rf = C ₆ F _{13 to} C _{12 to} F ₂₅ BPO: benzoyl peroxide DTBPO: after ditertiary butyl peroxide Treatment (1): Evaporator 120 ° C x 1 mmHg x 5 hours Post-treatment (2): Reprecipitation with methanol 3 90 ° C x 200 mmHg x 10hr Drying Post-treatment (3): Re-precipitation with methanol 4 after adding 30 g of chlorobenzene 90 ° C Drying at × 200 mmHg × 10 hr In Example 6, synthesis was performed under normal pressure and N ₂ atmosphere using a 200 ml glass flask instead of an autoclave. Further, in Examples 8 to 11, after the reaction was completed, the reaction solution at 100 ° C. was poured into methanol 3 at room temperature to reprecipitate the fluorinated polyolefin, and then the solution was added under reduced pressure of 200 mmHg.
The desired product was obtained by a method of drying at 0 ° C. for 10 hours. Further, in Examples 12 to 20, after the reaction was completed, 30 g of chlorobenzene was added to the reaction solution, and the mixture was heated to 100 ° C., and then poured into methanol 4 at room temperature, followed by the same method as in Examples 8 to 11. I got something.

Next, in order to examine the water and oil repellency of each fluorine-containing polyolefin obtained here, n-hexadecane, glycerin,
The contact angle of water was measured. The contact angle was measured at 23 ° C. using Kyowa Interface Science Co., Ltd. The measurement sample used was a sheet-like material obtained by pressing a fluorine-containing polyolefin between polyimide films and pressing at 190 ° C. Table 2 shows the measurement results.

As a comparative example, a high-density polyethylene (D) and a Teflon sheet were also measured. High density polyethylene (D) of Comparative Example 1
In the case of (2), the contact angle cannot be measured because n-hexadecane instantaneously wets almost completely. On the other hand, in the case of the fluorine-containing polyolefin according to the present invention, the contact angle of n-hexadecane shows a value equal to or larger than that of the Teflon sheet of Comparative Example 2, and it can be seen that extremely high oil repellency is exhibited. Further, the contact angles of glycerin and water show values equal to or higher than those of the Teflon sheet, and it is clear that the fluorine-containing polyolefin produced by the method of the present invention exhibits excellent water and oil repellency.

Next, application of the fluorine-containing polyolefin according to the present invention as an additive for surface modification was attempted. That is, a small amount of a fluorinated polyolefin is added to the high-density polyethylene (D),
A sample melt-blended in a melt extruder (190 ° C.) was pressed into a sheet by the method described above, and the contact angle of n-hexadecane with this sample was measured. Table 3 shows the measurement results.
Shown in

The amount of addition of the fluorine-containing polyolefin was
0.5 wt% and others are 1.0 wt% (all are wt% based on high density polyethylene (D)). From this, it can be seen that oil repellency can be imparted to ordinary polyolefins by blending only a small amount of the fluorinated polyolefin.

Test Example The fluorinated polyolefin of Example 11 and Comparative Example 3
A sheet was obtained by sandwiching the sample of Example 6 of JP-A-61-23216 between polyimide films and pressing at 190 ° C. This sheet is placed in a 15% by weight aqueous sodium hydroxide solution, treated at 80 ° C. for 24 hours, washed with a large amount of water, dried at 60 ° C. for 16 hours, and the contact angle of n-hexadecane before and after the treatment is adjusted. The measurement was performed at 23 ° C. using an interface science device. Table 4 shows the results.

From the results in Table 4, it can be seen that the product of Example 11 has a small deterioration due to hydrolysis, while the product of Comparative Example 3 has a large deterioration due to hydrolysis.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-23616 (JP, A) JP-A-52-4589 (JP, A) JP-B-48-29549 (JP, B1)

Claims (2)

(57) [Claims] 1. A polyolefin and a fluorine-containing olefin compound having no ester bond in an amount of 1 to 1000% by weight with respect to the polyolefin, comprising carbon, fluorine and, if necessary, hydrogen and / or another halogen atom. 2-20 carbon atoms, 1 fluorine atom
Grafting by reacting with an olefin compound of 40 to 40 in the presence of a radical initiator and in the presence of a solvent that dissolves the raw material polyolefin is characterized by excellent water and oil repellency and hydrolysis resistance. A method for producing a fluoropolyolefin. 2. The method for producing a fluorinated polyolefin according to claim 1, wherein the polyolefin is polyethylene, polypropylene, poly 1-butene, poly 4-methyl-1-pentene.