WO1998045526A1

WO1998045526A1 - Synthesis of fluorinated copolymers in a hydrocarbonic medium

Info

Publication number: WO1998045526A1
Application number: PCT/FR1998/000657
Authority: WO
Inventors: Jean-Marc Corpart; André Dessaint; Casimir Kalinka; Marie-José Lina; Denis Tembou Nzudie
Original assignee: Elf Atochem S.A.
Priority date: 1997-04-09
Filing date: 1998-04-01
Publication date: 1998-10-15
Also published as: AU7053998A; FR2762000B1; FR2762000A1

Abstract

The invention relates to the synthesis of fluorinated copolymers, and is intended for use in the hydrophobic and oil repellent treatment of textiles and leather. It specifically concerns a fluorinated copolymer solution in a hydrocarbonic solvent with a solubility factor of between 7 and 8 (cal/cm3)1/2 and a flash point equal to or higher than 55 °C. The copolymer is formed from a mixture of monomers comprising at least one fluorinated (meth)acrylate, at least one non-fluorinated lipophilic monomer, and at least one silicated monomer.

Description

SYNTHESIS OF FLUORINATED COPOLYMERS IN HYDROCARBON MEDIA

DESCRIPTION

The present invention relates to the field of fluorinated copolymers and more particularly relates to the synthesis of fluorinated copolymers in a hydrocarbon medium.

Fluorinated products intended for the hydrophobic and oleophobic treatment of textiles and leather can be applied in different forms, in particular during the dry cleaning of substrates or in the form of waterproofing aerosol. In all cases, they must be perfectly soluble in the solvents used. For dry cleaning, there are two main classes of solvents. The first, widely used, is that of halogenated and in particular chlorinated solvents such as perchlorethylene; In this category, hydrochlorofluorinated solvents such as 1, 1-dichloro-1-fluoroethane (HCFC 141b) are also used, but on a more ad hoc basis. Thus, US patents 4,366,300 and US 3,341,497 describe fluorinated compositions used for hydrophobic and oleophobic treatment and presented in chlorinated solvents such as trichlorethylene, perchlorethylene and 1, 1, 1-trichloroethane. Similarly, patent application WO 95/11949 proposes oleophobic and hydrophobic water-repellent fluorinated agents, used in dry cleaning and synthesized in a solvent of the hydrochlorofluorocarbon or hydrofluorocarbon type. However, most of these solvents have a negative effect on the ozone layer and recent decisions, taken worldwide to protect this ozone layer, already prohibit the manufacture of solvents such as 1, 1 , 2-trichloro-1,2,2-trifluoroethane (CFC 113) and 1, 1, 1-trichloroethane.

A second class of solvents which can be used for dry cleaning consists of petroleum or hydrocarbon solvents. Historically, white spirit was used for many years until the mid-1960s when it was gradually replaced by perchlorethylene; among the disadvantages associated with white spirit, we can mention its marked flammability with a flash point of 38 ° C. The hydrocarbons available today for dry cleaning are characterized by a lower flammability and also by a lower content of aromatic compounds making it possible to avoid residual odors on clothing. These hydrocarbons, the number of carbon atoms of which is generally between 10 and 15, are all second category flammable liquids with a flash point greater than or equal to 55 ° C; their chemical structure is variable since n-paraffins (linear molecular skeletons), isoparaffins (branched molecular skeletons) and de-aromatized paraffins (branched and cyclic molecular skeletons) can be used. In terms of dry cleaning, the cleaning power of these hydrocarbons and their aggressiveness are of the same level as those of CFC 113 and lower than those of perchlorethylene. These properties allow their use on delicate textile structures and leathers. However, very few fluorinated oleophobic and hydrophobic products have been proposed in such solvents; the essential difficulty in using hydrocarbons for the synthesis of fluorinated products is due to their weak power to dissolve such products. Thus, in the case of a fluorinated copolymer, any increase in the relative proportion of perfluoroalkylated monomer is generally opposed to obtaining compositions of practical interest because it tends to be accompanied by degradation of storage stability with , mainly, deposit formation. On the other hand, even if it can improve stability, an increase in the relative proportion of fluorine-free monomers is most often at the expense of hydrophobic and oleophobic performances. It may also be mentioned that the use of monomers with or without polar groups capable of improving the adsorption of the polymer on the substrate to be treated or of allowing chemical reactions after application to the support (crosslinking for example) is problematic and is generally done to the detriment of the storage stability of the final composition.

The difficulty linked to the choice of hydrocarbons as solvent can be circumvented by using for the synthesis a mixture of polar solvent and hydrocarbon, as is proposed in patent applications JP 6 240 238 and JP 6 248 257. Although these two Patent applications provide for the possibility of using only a hydrocarbon solvent such as decane, undecane or dodecane, they prefer to use a mixture of such a solvent with at least 10% by weight of a polar solvent. Likewise, US Pat. No. 5,284,902 claims the preparation of a fluorinated copolymer in a mixture of solvents, one of which is polar, followed by dilution in a hydrocarbon solvent.

However, the introduction of a second solvent into the composition causes a complication during dry cleaning. The polar solvent can in particular become a source of pollution inside the dry cleaning machine. On the other hand, it is more aggressive than hydrocarbon and can damage fragile textiles.

New fluorinated copolymers have now been found which can be synthesized in solution in a hydrocarbon solvent used alone (that is to say without resorting to the use of a polar co-solvent) and which, after application to the support, are crosslinkable, which makes it possible to maintain the hydrophobic and oleophobic properties of the support after machine washing or dry cleaning. The subject of the invention is therefore a solution of fluorinated copolymer in a hydrocarbon solvent, characterized in that said solvent has a solubility parameter of between 7 and 8 (cal / cm ³ ) ^1/2 and a higher flash point or equal to 55 ° C. and in that the fluorinated copolymer consists of units originating from a mixture of monomers comprising by weight:

(a) 20 to 89%, preferably 30 to 70%, of one or more fluorinated monomers corresponding to the general formula:

R1

CH ₂ = C (I)

C ≈ O

I O - A - Rp

in which Rp represents a linear or branched perfluoroalkyl radical containing 2 to 20 carbon atoms (preferably 4 to 16), A represents a bivalent chain linked to O by a carbon atom and which may contain one or more oxygen atoms , sulfur and / or nitrogen, and R ¹ represents a hydrogen atom or a methyl radical;

(b) 10 to 79%, preferably 20 to 60%, of one or more lipophilic non-fluorinated monomers chosen from the compounds of general formulas (II) and (III): R ²

CH ₂ = C - COOR ³ (II)

CH ₂ = CH - B - R3 (III)

in which R2 represents a hydrogen atom or a methyl radical, B is absent or represents a bivalent chain which can comprise one or more oxygen and / or nitrogen atoms, and R ³ represents an alkyl radical, linear or branched, containing from 8 to 36 carbon atoms (preferably 12 to 24); (c) 1 to 20%, preferably 1.5 to 10%, of one or more silicon monomers chosen from the compounds of general formulas (IV) and (V):

R4 CH ≈ C OR ⁵ (IV)

COO - D - Si - R ⁶ 0R5

/ CH ₂ = CH - Si - R6 (V) R7

in which R ⁴ represents a hydrogen atom or a methyl radical, D represents a bivalent chain which can comprise one or more oxygen, nitrogen and / or sulfur atoms, R5 represents an alkyl radical containing from 1 to 4 atoms carbon, Rβ and R ⁷ , identical or different, each represents an alkyl or alkoxy radical containing from 1 to 4 carbon atoms; and

(d) from 0 to 30%, preferably 2 to 15%, of any one or more monomers other than the monomers of formulas I, II, III, IV and V.

The fluorinated monomers of formula (I) are preferably chosen from the acrylates and methacrylates of fluorinated alcohols of formulas (VI) to (VIII):

Rp (CH ₂ ) _n - (X) p- (CH ₂ ) _m OH (VI)

R _F - (CH ₂ ) _r (OCH ₂ CH) _q OH (VII)

R _F -CH = CH- (CH ₂ ) _m OH (VIII)

in which Rp has the same meaning as in formula (I), X represents an oxygen or sulfur atom or a COO, SO ₂ , CONR or SO ₂ NR group, R representing an alkyl radical containing 1 to 4 atoms of carbon, n represents an integer ranging from 0 to 20 (preferably 0 to 2) but different from 0 if X is an oxygen or sulfur atom, p is equal to 0 or 1, the symbols m, q and r , identical or different, each represents an integer ranging from 1 to 20 (preferably equal to 1 or 2).

Fluorinated monomers of formula (I) which are particularly advantageous in the context of the invention are those corresponding to the general formula:

R1

CH ₂ = C (IX) COO - CH ₂ CH ₂ - (NR'S0 ₂ ) _p (CH ₂ ) _n - R _F

in which Rp and R ¹ have the same meaning as in formula (I), R 'represents a methyl or ethyl radical, p is equal to 0 or 1, and n is equal to 0 or 2. The monomers of formula (II ) or (III) have an alkyl chain which is sufficiently lipophilic to ensure perfect solubility of the final copolymer in the hydrocarbons used for the synthesis. By way of nonlimiting examples of monomers (II), mention may be made of 2-ethylhexyl acrylate or methacrylate, octyl or isooctyl acrylate or methacrylate, acrylate or nonyl methacrylate, acrylate or lauryl methacrylate, stearyl acrylate or methacrylate, arachidyl acrylate or methacrylate and behenyl acrylate or methacrylate. The monomers of formula (III) are advantageously chosen from alkylvinyl esters (B being a -0-CO- bridge), alkylallyl esters (B being a -CH ₂ -0-CO- bridge), and alkylvinyl ethers (B = 0). By way of nonlimiting examples, mention may be made of vinyl stearate, hexadecylvinyl ether, dodecyvinyl ether and octa-decylvinyl ether.

As examples of monomers of formula (IV), mention may be made of [3- (methacryloyloxy) propyl] dimethylethoxysilane and especially [3- (methacryloyloxy) propyl] trimethoxysilane. As an example of monomers (V), there may be mentioned triethoxyvinylsilane.

The monomer (s) (d) can be of very variable structure, but are preferably chosen from the acrylates and methacrylates of formula (X):

R8

CH ₂ = C-COO-EY (X)

in which R ⁸ represents a hydrogen atom or a methyl radical, E represents an alkylene radical containing 2 to 4 carbon atoms and Y represents an OH or NR9R10 group, R9 representing an alkyl radical containing 1 to 4 carbon atoms and R10 a hydrogen atom or an alkyl radical containing 1 to 4 carbon atoms. As examples of such monomers, there may be mentioned more particularly 2-hydroxyethyl acrylate and methacrylate, dimethylaminoethyl methacrylate and N-tertiobutylaminoethyl methacrylate.

The products according to the invention are prepared according to a batch or semi-continuous process by radical copolymerization of the various monomers in solution in a hydrocarbon solvent or in a mixture of hydrocarbon solvents having a solubility parameter of between 7 and 8 (cal / cm ³ ) ¹ - ^ and a flash point greater than or equal to 55 ° C. These solvents can be n-paraffins, isoparaffins or dearomatized paraffins whose carbon number is between 10 and 15. Isoparaffins are preferred.

The total concentration of the monomers and, consequently, that of the fluorinated copolymer in the final solution can vary from 5 to 60% by weight and, preferably, from 20 to 50%. The polymerization is carried out in the presence of initiator (s) which are used in an amount of 0.1 to 4%, and preferably 0.5 to 2% relative to the total weight of the monomers used. As initiators, there can be used peroxides such as benzoyl peroxide, lauroyl peroxide, succinyl peroxide and tert-butyl perivalate, or diazo compounds such as azo-2,2'-bis-isobuty - ronitrile, Pazo-4,4'-bis- (cyano-4-pentanoic) and azodicarbonamide. One can also operate in the presence of UV radiation and photo-initiators such as benzophenone, methyl-2-anthraquinone or chloro-2-thioxanthone. The length of the polymer chains can, if desired, be adjusted using chain transfer agents such as alkyl mercaptans, carbon tetrachloride or triphenylmethane, used in an amount of 0.05 to 1% based on the total weight of monomers. The reaction temperature can vary within wide limits, ranging from room temperature to the boiling point of the reaction mixture. Preferably, one operates between 60 and 95 ° C. The subject of the invention is also the fluorinated copolymers as defined above.

The solutions of fluorinated copolymers according to the invention are more particularly intended for the hydrophobic and oleophobic treatment of textiles and leathers, and can be applied directly in the dry cleaning machine. They can also be used, on the same substrates, outside of dry cleaning machines, in the form of waterproofing aerosol, by spraying or by impregnation in a bath.

The copolymer solutions according to the invention can also be applied with advantage on other supports, in particular on building materials such as concrete, stones, tiles, bricks. In this case, the application is carried out under conditions well known to those skilled in the art: by brush, with a roller, by spraying.

For applications other than dry cleaning, the products can be diluted in any solvent or mixture of solvents compatible with the synthetic solvent. In all cases, it is possible, to obtain a particular effect or better fixation, to advantageously combine the fluorinated copolymers according to the invention with certain adjuvants (polymers, crosslinking products, catalysts). Mention may be made, for example, of hydrophobic extenders comprising aziridine or anhydride groups. At the time of application, the concentration of the fluorinated copolymers according to the invention is generally between 0.5 and 5% and preferably between 1 and 3%. The quantities of solution applied depend on the substrate to be treated; they can vary between 20 and 2000 g / m ² .

After application, the treated substrates are generally dried at room temperature. They can also be dried by heating. The treated articles have good hydrophobic and oleophobic properties which can be evaluated by the following application tests: Oleophobia Tβsts

The oleophobia is measured according to the test described in the standard "AATCC Technical Manual", Test Method 118 (1985) which evaluates the non-wettability of the substrate by a series of oily liquids whose surface tensions are increasingly low. The rating of the treated substrate is defined as the maximum value of the test liquid which does not wet the support after a contact time of 30 seconds. The test liquids used in the evaluation are listed in the following table:

Hydrophobia tests

The hydrophobic effect is measured using test solutions numbered from 1 to 10 and consisting of water / isopropanol mixtures in the following weight proportions:

The test consists in depositing drops of these mixtures on the treated substrates, then observing the effect produced. We give a rating by giving the number corresponding to the solution which contains the highest percentage of isopropanol and which has not penetrated or wetted the substrate after 30 seconds of contact.

Water resistance test (spray test)

This test, described in the standard "AATCC Technical Manual", Test Method 22 (1985), makes it possible to evaluate the resistance to wetting of the treated tissues. 250 ml of water are poured from a height of 15 cm, via a funnel ending in an aluminum sprinkler, onto the fabric sample stretched over a frame with a diameter of 15.2 cm and tilted at 45 ° C. When all the water has been poured out, the frame is tapped on a hard surface to remove the excess water and the level of wetting is visually noted in relation to a series of 6 values indicated on a photographic reference published in the standard. The following table indicates the rating of the test according to the level of wetting:

The application tests can also be repeated after washing in the machine or dry cleaning of the treated articles, in particular in the case of textiles.

Machine washes at 40 ° C are carried out according to cycle 6A described in standard NF G 07-136 (1994). The fabrics are then dried in a tumble dryer at a temperature of the order of 55 ° C.

Dry cleaning is carried out as follows: the treated textiles are immersed for half an hour in perchlorethylene or in isoparaffin, then drained in an upright position and dried at room temperature for 48 hours.

EXAMPLES

The following examples, in which the parts are expressed by weight, unless otherwise stated, illustrate the invention without limiting it. EXAMPLE 1

220 parts of an isoparaffin are introduced into a reactor of 1000 parts by volume, equipped with an agitator, a thermometer, a reflux condenser, a nitrogen inlet and a heating device. (ISOPAR H from the company EXXON Chemical), having a boiling point of the order of 180 ° C, a flash point of 58 ° C and a solubility parameter of 7.3 (cal / cm ³ ) ¹ ^, 75 parts of stearyl methacrylate, 14.4 parts of 2-hydroxyethyl methacrylate, 6 parts of [3- (methacryloyloxy) propyl] trimethoxysilane and 1 10 parts of a mixture of fluorinated alcohol acrylates of formula:

CF ₃ (CF ₂ ) _n C ₂ H OOC-CH = CH ₂

where n is equal to 5, 7, 9, 11, 13, in mean and respective weight ratios of 1/63/25/9/3. The mixture is heated to 80 ° C. under a nitrogen atmosphere and 2.4 parts of azo are introduced.

2,2'-bis-isobutyronitrile suspended in 86 parts of ISOPAR H. The reaction is allowed to proceed for 4 hours, then 0.5 part of azo-2,2'-bis-isobutyronitrile is introduced and maintains the reaction medium for one hour at 80 ° C. The reaction mixture is then diluted with 160 parts of ISOPAR H, then the product is allowed to cool. A clear solution (S1) is obtained comprising 30% by weight of copolymer according to the invention.

EXAMPLE 2

The procedure is the same as in Example 1, but without the addition of 2-hydroxyethyl methacrylate. A clear solution is obtained (S2) comprising 29.1% by weight of copolymer according to the invention.

EXAMPLE 3

The procedure is the same as in Example 1, but replacing the 2-hydroxyethyl methacrylate with the same weight of dimethyllaminoethyl methacrylate. A clear solution is obtained (S3) comprising 30% by weight of copolymer according to the invention.

EXAMPLE 4 (Comparative) The procedure is the same as in Example 1, but without the addition of [3- (methacryloyloxy) propyl] trimethoxysilane. A clear solution (Sa) is obtained comprising 30% by weight of a copolymer not in accordance with the invention. EXAMPLE 5

The solutions (S1), (S2), (S3) and (Sa) are diluted with Plsopar H to a mass concentration of 2% of copolymer. The solutions obtained are applied by spraying onto cotton at a rate of the order of 50 g / m ² . The treated fabrics are then dried at room temperature for 48 hours, then subjected to the application tests before and after a machine wash. The following tables bring together the results obtained.

- results before washing:

- results after washing

Examination of the above tables shows that, while the presence of [3- (methacryloyloxy) propyl] trimethoxysilane has little influence on the application results before washing, it is however decisive for improving the durability of the fluorinated treatment subjected to machine washing .

EXAMPLE 6

The solution (S1) is diluted with isopropyl acetate or heptane to a mass concentration of 1% of copolymer. The solutions obtained are applied by spraying on lambskin (stain from the Desprat company) at a rate of the order of 100 g / m ² . The treated leathers are dried at room temperature for 48 hours, then subjected to application tests.

EXAMPLE 7

The solutions (S1) and (Sa) are diluted with perchlorethylene to a mass concentration of 2% of copolymer. The solutions obtained are applied by spraying onto cotton at a rate of the order of 50 g / m ² . The treated fabrics are then dried at room temperature for 48 hours, then subjected to application tests before and after dry cleaning in perchlorethylene. The following tables bring together the results obtained.

- results before dry cleaning:

- results after dry cleaning:

Examination of the above tables shows that the presence of [3- (methacryloyloxy) propyl] trimethoxysilane is decisive for improving the durability of the fluorinated treatment subjected to dry cleaning with perchlorethylene.

EXAMPLE 8

The solutions (S1) and (Sa) are diluted with Isopar H to a mass concentration of 2% of copolymer. The solutions obtained are applied by spraying onto polyester at a rate of the order of 50 g / m ² . The treated fabrics are then dried at room temperature for 48 hours, then subjected to application tests before and after dry cleaning in Isopar H. The following tables show the results obtained. - results before dry cleaning:

results after dry cleaning

Claims

1. Solution of fluorinated copolymer in a hydrocarbon solvent, characterized in that said solvent has a solubility parameter between 7 and 8 (cal / cm ³ ) ¹ ^ and a flash point greater than or equal to 55 ° C and in that the fluorinated copolymer consists of units originating from a mixture of monomers comprising by weight:

(a) 20 to 89% of one or more fluorinated monomers corresponding to the general formula:

R1 CH ₂ = C-COO-A-Rp (I)

in which Rp represents a linear or branched perfluoroalkyl radical containing 2 to 20 carbon atoms, A represents a bivalent chain linked to O by a carbon atom and which may contain one or more oxygen, sulfur and / or d atoms nitrogen, and R1 represents a hydrogen atom or a methyl radical;

(b) 10 to 79% of one or more lipophilic non-fluorinated monomers chosen from the compounds of general formulas:

R2

CH ₂ = C - COOR ³ (II)

CH ₂ = CH - B - R ³ (III)

in which R2 represents a hydrogen atom or a methyl radical, B is absent or represents a bivalent chain which can comprise one or more oxygen and / or nitrogen atoms, and R ³ represents an alkyl radical, linear or branched, containing from 8 to 36 carbon atoms;

(c) 1 to 20% of one or more silicon monomers chosen from the compounds of general formulas:

R4 OR ⁵

CH ₂ = C-COO-D-Si - R ⁶ (IV) R ⁷

OR5 I

CH ₂ = CH - Si - R ⁶ (V) in which R ⁴ represents a hydrogen atom or a methyl radical, D represents a bivalent chain which can comprise one or more oxygen, nitrogen and / or sulfur atoms, Represents an alkyl radical containing from 1 to 4 atoms carbon, R ^ and R ⁷ , identical or different, each represent an alkyl or alkoxy radical containing from 1 to 4 carbon atoms; and

(d) from 0 to 30% of any one or more monomers other than the monomers of formulas I, II, III, IV and V.

2. Solution according to claim 1 wherein the hydrocarbon solvent is a paraffin or a mixture of paraffins containing from 10 to 15 carbon atoms, preferably an isoparaffin or a mixture of isoparaffins.

3. Solution according to claim 1 or 2 in which the copolymer results from the polymerization of a mixture of monomers comprising: - 30 to 70% of monomer (s) of formula (I),

- 20 to 60% of monomer (s) of formula (II) or (III),

- 1.5 to 10% of monomer (s) of formula (IV) or (V), and

- 2 to 15% of monomer (s) other than those of formula I, II, III, IV and V.

4. Solution according to one of claims 1 to 3 wherein the radical Rp contains from 4 to 16 carbon atoms and R ³ contains from 12 to 24 carbon atoms.

5. Solution according to one of claims 1 to 4 in which the monomer (s) of formula (I) corresponds (s) to the general formula:

R1 CH ₂ = C (IX) COO - CH ₂ CH ₂ - (NR'SO ₂ ) _p (CH ₂ ) _n - Rp

in which R 'is a methyl or ethyl radical, p is equal to 0 or 1, and n is equal to 0 or 2.

6. Solution according to one of claims 1 to 5 wherein the monomer or monomers of formula (II) are chosen from acrylates and methacrylates of 2-ethylhexyl, octyl, isooctyl, nonyl, lauryl, stearyl, arachidyl and behenyl.

7. Solution according to one of claims 1 to 5 wherein the monomer (s) of formula (III) are chosen from hexadecylvinylether, dodecylvinylether and octadecylvinylether.

8. Solution according to one of claims 1 to 7 wherein the monomer of formula (IV) is [3- (methacryloyloxy) propyl] -trimethoxysilane.

9. Solution according to one of claims 1 to 8 wherein the monomer (d) is 2-hydroxyethyl acrylate or methacrylate, dimethyllaminoethyl methacrylate or N-tert-butylaminoethyl methacrylate.

10. Solution according to one of claims 1 to 9 containing 5 to 60% by weight of fluorinated copolymer, preferably 20 to 50%.

11. Use of a solution according to one of claims 1 to 10 for the hydrophobic and oleophobic treatment of textiles, leathers and other supports.

12. Fluorinated copolymer as defined in claim 1.