JP2001213956A - Method for purifing both-terminals-vinylted perfluoropolymer compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for easily removing a one-terminal-vinylated polymer of formula (2): R2-Rf-(Z)a-CH=CH2 [Z is -CH2-, -CH2O-, -CH2OCH2-, or -Y-NR1-CO- (Y is -CH2- or a group of the formula; and R1 is H or an optionally substituted monovalent hydrocarbon group); Rf is a divalent perfluoroalkylene or a divalent perfluorooxyalkylene; each a is independently 0 or 1; and R2 is H, F, or a monovalent alkyl optionally containing an ether oxygen atom in the molecular chain] from a polymer mixture which mainly comprises a both-terminals-vinylated polymer of formula (1) [Z, Rf, and a are each the same as those in formula (2)] and contains a one-terminal-vinylated polymer as an impurity to thereby purify the both-terminals-vinylated polymer. SOLUTION: The method comprises bringing the polymer mixture into contact with an adsorbent to selectively cause the one-terminal-vinylated polymer to be adsorbed and removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for purifying a double-ended vinylated perfluoropolymer compound.

[0002]

In general, the general formula _{(1): CH 2 = CH-} (Z) a -Rf- (Z) a -CH = CH 2 (1) [ wherein, Z is -CH ₂ -, - CH _{2 0 -, - CH 2 0CH} 2 -, or -Y
-NR ¹ -CO- (where Y is -CH ₂ -or a formula:

[0003]

Embedded image A group represented by R ¹ is a hydrogen atom or a substituted or unsubstituted
Rf is a divalent perfluoroalkylene group or a divalent perfluorooxyalkylene group, and a is independently O or 1.] When producing a fluoropolymer compound,
General formula (2) as a by-product: R ² —Rf— (Z) _a —CH ＝ CH ₂ (2) wherein Z, Rf and a are the same as above, and R ² is a hydrogen atom, fluorine Atom or a monovalent alkyl group (which may contain an etheric oxygen atom in the chain)]. The both-terminal vinylated perfluoropolymer compound represented by the general formula (1) is used to obtain a cured product by performing a crosslinking reaction using a curing agent. This cured product has excellent heat resistance, solvent resistance, chemical resistance, surface characteristics, flame retardancy, low temperature characteristics and moisture permeability due to the characteristics of fluorine, and is more excellent in processability and workability than conventional fluororubber. Useful as

However, the terminal vinyl group present in the one-terminal vinyl compound of the general formula (2), which is an impurity, has almost the same reactivity as the terminal vinyl group of the both-terminal vinyl compound of the general formula (1), At the time of the curing, it reacts with the cross-linking agent in the same manner as the vinylated product at both ends of the general formula (1), so that the cross-linking terminal is blocked during the cross-linking reaction. This gives the general formula (1)
The physical properties of the cured product of the vinylated product at both ends are greatly reduced as the content of the vinylated product at one end of the general formula (2) in the raw material increases.

[0005]

Therefore, in order to obtain a cured product having good physical properties, the general formula (2)
It is necessary to remove the vinylated compound at one end, but since it is a polymer, it is difficult to separate it by distillation under reduced pressure, and a large amount of polymer cannot be treated by chromatography or the like. Therefore, the general formula contained in the polymer of the general formula (1)
A method for easily removing and purifying the vinylated product at one end of (2) is desired. An object of the present invention is to provide a simple method for purifying such a perfluoropolymer compound having vinyls at both ends.

[0006]

The present invention provides a compound of the general formula
Purification by a simple procedure by contacting a polymer mixture containing a vinylated perfluoropolymer compound at both ends represented by (1) as a main component and a vinylated compound at one end of the general formula (2) as an impurity with an adsorbent. I found that I can do it.

That is, the present invention provides, as a means for solving the above-mentioned problems, the following general formula (1): CH ₂ ＝ CH- (Z) _a -Rf- (Z) _a -CH = CH ₂ (1) in, Z is _{-CH 2 -, - CH 2 0} -, - CH 2 0CH 2 -, or -Y
-NR ¹ -CO- (where Y is -CH ₂ -or a formula:

[0008]

Embedded image A group represented by R ¹ is a hydrogen atom or a substituted or unsubstituted
A monovalent hydrocarbon group), and Rf is a divalent perfluoroalkylene group or a divalent perfluorooxyalkylene group, and a is independently O or 1.] A fluoropolymer compound as a main component and an impurity represented by the following general formula (2):

R ² —Rf— (Z) _a —CH ＝ CH ₂ (2) wherein Z, Rf and a are the same as above, and R ² is a hydrogen atom, a fluorine atom, a monovalent alkyl group. (It may contain an etheric oxygen atom in the chain)], and a polymer mixture containing a vinylated perfluoropolymer compound at one end represented by the general formula (2) is contacted with an adsorbent. An object of the present invention is to provide a method for purifying a double-terminal vinylated perfluoropolymer compound, which comprises selectively adsorbing and removing the terminal vinylated perfluoropolymer compound.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
In the general formulas (1) and (2), Rf is a divalent perfluoroalkylene group or a divalent perfluoropolyether group. As the divalent perfluoroalkylene group, those represented by the formula:-(CF ₂ ) m- (where m = 1 to 10, preferably 2 to 6) are preferable, and divalent perfluoropolyether The group is preferably represented by the following formula.

[0011]

Embedded image (Wherein, X represents F or CF ₃ group, and p, q, and r are each p
≧ 0, q ≧ O, 2 ≦ p + q ≦ 200, especially 2 ≦ p + q ≦ 110, 0
≦ r ≦ 6.)

[0012]

Embedded image (Where r, s, and t are respectively 0 ≦ r ≦ 6, s ≧ 0, t ≧ 0, 0 ≦ s
+ T ≦ 200, especially 2 ≦ s + t ≦ 110)

[0013]

Embedded image (In the formula, X is F or CF ₃ groups, u and v are respectively 1 ≦ u ≦ 100, 1
≤ v ≤ 100 integer)

-CF ₂ CF ₂ (OCF ₂ CF ₂ CF ₂ ) _w OCF ₂ CF ₂ (where w is an integer of 1 ≦ w ≦ 100) Specific examples of Rf include the following. You.

[0015]

Embedded image (Where m is an integer of 1 to 100, and n is 1 to 10
Is an integer of 0)

[0016]

Embedded image (Where m is an integer of 1 to 100, and n is 1 to 10
Is an integer of 0)

[0017]

Embedded image (Where m is an integer of 1 to 100, and n is 1 to 10
Is an integer of 0)

[0018]

Embedded image (Where, n represents the average from 5 to 100) In the general formula (1) and (2), Z is -CH ₂ -, - CH ₂ 0
_{-, - CH 2 0CH 2 -} , or -Y-NR ¹ -CO- (where, Y is -CH ₂
-Or the formula:

[0019]

Embedded image A group represented by R ¹ is a hydrogen atom or a substituted or unsubstituted
A monovalent hydrocarbon group).

The monovalent hydrocarbon group represented by R ¹ is preferably a group having 1 to 12 carbon atoms, particularly preferably 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a butyl group and a pentyl group. , An alkyl group such as hexyl group, cyclohexyl group and octyl, an aryl group such as phenyl group and tolyl group, an aralkyl group such as benzyl group and phenylethyl group or a part or all of the hydrogen atoms of these groups is halogen such as fluorine. Examples include groups substituted with atoms and the like.

R ^{2 in the} general formula (2) is a hydrogen atom, a fluorine atom or a monovalent alkyl group (which may contain an etheric oxygen atom in the chain). May be substituted with a halogen atom such as fluorine, and the alkyl group may be cyclized. In particular, a perfluoroalkyl group includes a perfluoroalkyl group represented by the following formula: C _c F _{2c + 1} − (where c is an integer of 1 ≦ c ≦ 20). This perfluoroalkyl group may be linear or branched.

The content of the vinylated compound at one end represented by the general formula (2) in the polymer mixture purified by the method of the present invention is not particularly limited, but is generally 20 mol% or less in all polymer molecules. It is effective in some cases. In the method of the present invention, such a polymer mixture is contacted with an adsorbent.

Examples of the type of adsorbent used include activated carbon, diatomaceous earth, activated clay, silicate, activated alumina and the like, and one or a combination of a plurality of types can be used. Preferred are activated carbon, silicates and alumina. The amount of the adsorbent can be appropriately determined according to the content of the vinylated compound at one end represented by the general formula (2) in the polymer mixture and the type of the adsorbent, but preferably the polymer is used. It is 1 to 10 parts by weight based on 100 parts by weight of the mixture.

The contact between the polymer mixture and the adsorbent is desirably performed by stirring with a stirring blade or the like so that sufficient contact is achieved. The contact time between the polymer and the adsorbent may be an appropriate length as long as necessary for purification, and is not particularly limited, but is usually preferably 2 hours or more.

When the polymer mixture and the adsorbent are mixed and stirred, in order to improve the adsorption efficiency and facilitate the filtration after the reaction, the polymer mixture has a boiling point of 50 to 200 ° C. and a carbon number of 1 to 20.
It is preferable to dilute with a fluorinated solvent. The amount of the fluorinated solvent used is 20 to 4 parts per 100 parts by weight of the polymer mixture.
00 parts by weight is preferred. The fluorinated solvent used here is particularly preferably a perfluoroalkyl or a popurfluoroalkyl ether in view of the solubility of the polymer and the ease of removal after the contact, and specifically, Fluorinert FC-77 manufactured by 3M Company. (Product name), Garten SV of Audimond
−90 (trade name).

After contacting with the polymer mixture, the adsorbent can be easily removed by filtration. When dilution with a fluorinated solvent is performed, the solvent can be easily removed from the filtered polymer solution by distillation under reduced pressure. Thus, a purified vinylated compound at both ends represented by the general formula (1) can be obtained.

[0027]

The present invention is not limited to the following description by way of examples. Example 1 The following formula (3):

[0028]

Embedded image (3) (However, Rf is a formula:

[0029]

Embedded image In the formula, p and q each represent the number of repeating units, and a vinylated compound at both ends represented by the following formula (4):

[0030]

Embedded image (4) (However, Rf ″ is a formula:

[0031]

Embedded image In the formula, r is the number of repeating units, and a perfluoropolyether group represented by
Containing polymer mixture (compound of general formula (3) and general formula
The average number of repeating units of the polymer mixture composed of the compound of (4) is 102) 500 g of the polymer mixture
With 3M fluorinated solvent Fluorinert FC-77 (trade name)
Diluted with 500 g, mixed with 25 g of activated carbon (made by Takeda Pharmaceutical Co., Ltd., trade name: egret AS) and 15 g of silicate (made by Kyowa Chemical Co., Ltd., trade name: Kyoward 700SL) as an adsorbent, and allowed to stand at room temperature for 12 hours. Stirred. After the adsorbent was removed by filtration from the solution after stirring, 15 g of activated carbon and 25 g of silicate were added again, mixed and stirred for 12 hours. After filtering the adsorbent, 2mmHg / 170 ℃
For 6 hours to obtain a purified polymer. ¹⁹ F
The content of the vinylated compound at one end represented by the formula (4) determined by NMR is 3.2 mol%, and the vinylated product at both ends of the formula (3) is
The average number of repeating units as a whole of the mixture with the vinylated compound at one end of (4) was 105.

Reference Example 1 The polymer mixture before the purification treatment and the polymer mixture after the purification treatment performed in Example 1
6 g is diluted with 24 g of Florinert FC-77 (trade name),
The obtained diluted product has the following formula (5):

[0033]

Embedded image (5) bifunctional fluorine-containing hydrogen siloxane is added in such an amount that the molar ratio (H / Vi) of the Si-H group of the fluorine-containing hydrogen siloxane and the vinyl group of the polymer mixture becomes 1.00, Further, chloroplatinic acid is converted into the following formula (6):

[0034]

Embedded image 0.012 g of a toluene solution of a catalyst modified with vinylsiloxane represented by (6) (platinum concentration 0.5% by weight) was added and mixed. Then, after heating the obtained composition solution at 60 ° C. for 12 hours, the viscosity of the solution was measured at 25 ° C. as it was. Table of results
Shown in 1.

[0035]

Table 1 Relationship between H / Vi molar ratio and solution viscosity From the results in Table 1, it can be seen that the increase in viscosity under the same conditions of the molar ratio of H / Vi = 1.
It shows a value of 1.5 times. This indicates that the blocking of the cross-linking terminal by the vinylated perfluoropolymer compound at one end was significantly reduced after the purification treatment.

[0036]

According to the purification method of the present invention, the vinylated perfluoropolymer compound at one end, which is contained as an impurity in the vinylated perfluoropolymer compound at both ends, is effectively and selectively removed, so that a highly pure vinylated perfluoropolymer compound is obtained. A terminally vinylated perfluoropolymer compound is obtained.

Claims (2)

[Claims] 1. A following general formula _{(1): CH 2 = CH-} (Z) a -Rf- (Z) a -CH = CH 2 (1) [ wherein, Z is -CH ₂ -, - CH _{2 0 -, - CH 2 0CH 2} -, or -Y
-NR ¹ -CO- (where Y is -CH ₂ -or a formula: A group represented by R ¹ is a hydrogen atom or a substituted or unsubstituted
Rf is a divalent perfluoroalkylene group or a divalent perfluorooxyalkylene group, and a is independently O or 1.] A perfluoropolymer compound as a main component, and as an impurity, the following general formula (2): R ² —Rf— (Z) _a —CH ＝ CH ₂ (2) wherein Z, Rf and a are the same as those described above. There, R ² is a hydrogen atom, a fluorine atom, adsorb monovalent alkyl group (which may contain an etheric oxygen atom in the chain) a is a polymer mixture containing one terminal vinylation perfluoropolymer compound represented by A method for purifying a vinylated perfluoropolymer compound having both terminals, characterized by selectively adsorbing and removing the vinylated perfluoropolymer compound having one terminal represented by the general formula (2) by bringing the compound into contact with an agent. 2. The method according to claim 1, wherein the contact of the polymer mixture with the adsorbent is carried out in a state where the polymer mixture is diluted with a fluorinated solvent having a boiling point of 50 to 200 ° C. and 1 to 20 carbon atoms. Purification method.