MC200041A1 - Fluoride acrylic copolymer type anti-graffiti varnish for the protection of organic polymer type supports - Google Patents

Abstract

The present invention relates to the preparation of a hydrophobic and oleophobic anti-graffiti protective varnish, with anti-soiling properties for the protection of supports of organic polymer type such as PVC and PET. This varnish is prepared by radical polymerisation of a composition containing by weight:[A], 10-70 percent, with respect to the total composition, of a mixture containing:(a) 40-99 percent by weight with respect to [A] of styrene or an acrylate or methacrylate monomer having 1-18 carbon atoms in the alkylated group,(b) 0.1 to 60 percent by weight with respect to [A] of a fluorinated monomer of general formula:<IMAGE>wherein:-RF denotes a linear or branched perfluoroalkyl chain, CmF2m+1 (m = 1-22).-R denotes a hydrogen atom or a linear or branched alkyl group containing 1-4 carbon atoms.-n varies from 1 to 15.(c) 0.2 to 2 percent with respect to [A] of radical initiator[B], 0-80 percent by weight with respect to the total composition of polymerisation solvent.The polymer obtained is deposited without further alteration, without being isolated from the reaction medium; in this case, the polymerisation solvent is also the deposition solvent; or the polymer is isolated, then deposited in pure state or in a solvent other than the polymerisation solvent.

Description

20 0 0 4 1 0021.71 DUPLICATE ' 3 1 A0UI 2001

PATENT OF INVENTION * 1 2 12 ;Title of the invention: ;FLUORIDED ACRYLIC COPOLYMER TYPE ANTI-GRAFFITI VARNISH FOR THE PROTECTION OF ORGANIC POLYMER TYPE SUBSTRATES ;Inventors: S. Saidi, F. Guittard, S. Geribaldi, M. Mateu, C. Baudrion ;The invention relates to the formulation and use of hydrophobic and oleophobic fluorinated copolymers as anti-graffiti protection for PET and PVC type substrates and more generally for organic polymer type substrates ;5 Graffiti constitutes a problem of increasing magnitude which affects all the metropolises of the industrial world. For example, in Paris, over 170,000 square meters were covered in graffiti in 1996, compared to 33,000 square meters in 1985. To address this problem, various methods have been developed, the most effective being the use of coatings designed to protect surfaces susceptible to tagging. Various formulations have thus been developed. Depending on whether permanent protection is desired, the choice of constituents in the preparation varies. In the case of sacrificial coatings, the formulations are generally based on waxes, silicates, polysaccharides, or acrylic polymers. These have the advantage of being inexpensive and relatively non-toxic. [M. Vo-15 Thanh (CASCO Xobel France. FR). FR 2 683 540, 1991; C. Brett (Morton International GmbH).] DE 197 43 566 Al. 1997; A. Pierre (AGRIPAX (S.A)), FR 2 686 614, 1992 j. ;Conversely, if resistance and permanence of the coating are desired;2;anti-graffiti, even after various washing cycles and with regard to external atmospheric effects, the use of polyurethanes, silicones, or fluorinated polymers is more suitable. ;In the case of polyurethanes, the formulations have the disadvantage of requiring dry surfaces and the compositions generally contain significant levels of VOCs (Volatile Organic Compounds). The quality of the coating remains mediocre, and several surface defects are often observed. This aspect improves in the case of silicone paints, but they remain poorly, if at all, impermeable to oils. Moreover, it is often necessary to pretreat the surface before the actual treatment [L. Brandt, C. Flosbach, R. Kalus, W. Schubert (Herberts Gesellschalft mit Beschraukter Haftung, Wuppertal, DE), US 5 426 151, 1993; C. Meynier, J.-L. Tarrade (C. Meynier, J.-L. Tarrade), FR 2 681 072, 1991; J.-C. Coppa (COPPA et Cie, SARL), FR 2 684 682, 1991], ;In the case of fluorinated polymers, three main classes have been developed: 15 - acrylates; ;- polyethers; ;- perfluoroalkylalkoxysilanes. ;The corresponding coatings are generally more efficient than those described previously [A. L. Dessaint, M.-J. Lina (Atochem, Courbevoie, France), US 4,478,975, 20, 1984; R. Marchetti, P. Voghera, S. Turri (Ausimont SpA, Milan), EP 739,923, 1996; H. Kishita, K. Yamaguchi, T. Takago (Shin-Etsu Chemical Co., Ltd., Tokyo), US 4,985,526, 1990]. However, they still have specific drawbacks, which considerably restrict their range of applications. For example, these coatings have the following drawbacks: difficulty applying them to the surface to be treated, their ineffectiveness on certain graffiti colors, and the need for perfectly clean, dry surfaces free of any oily residue. The impossibility of application on certain painted surfaces, their frequent harmfulness due to the presence of volatile solvents, and their often easy removal over time or in the presence of the solvent used to clean the graffiti. ;30 The present invention falls within the field of fluorinated acrylic coatings and more particularly fluorinated acrylic copolymers. These varnishes are used primarily as hydrophobic and oleophobic anti-graffiti agents, with anti-adhesive and anti-fouling properties for various organic polymer substrates. Examples of substrates include: polyethylene, polyvinyl chloride (PVC), polyacrylates, polymethacrylates, polypropylene, polyamides, polyurethanes, acrylonitrile butadiene styrene (ABS), saturated or unsaturated polyesters such as polyethylene terephthalate (PET), polycarbonates, polyacrylamides, Teflon (PTFE), polysiloxanes, and polysaccharides. According to the invention, the varnishes are obtained by radical polymerization of a composition containing: [A] from 10 to 70% by weight relative to the final composition, of a mixture containing: 1) 40 to 99% by weight relative to [A], preferably 65 to 95%, of styrene or of an acrylate or methacrylate type monomer having 1 to 18 carbon atoms in the alkyl group. 2) 0.1 to 60% by weight relative to [A], preferably 3 to 35%, of a fluorinated monomer of general formula: in which: Rf denotes a linear or branched perfluoroalkyl chain CmF2m+1 (m = 1 to 22) and more particularly C4F8, C6F13 and CgF^; ;♦R denotes a hydrogen atom or a linear or branched alkyl group containing 1 to 4 carbon atoms; ;♦n varies from 1 to 15; ;3)- from 0.2 to 2 wt% relative to [A], preferably from 0.4 to 1 wt% of the radical initiator listed below; ;[B] from 0 to 80 wt% relative to the total composition, preferably from 30 to 60 wt% of one or more polymerization solvents listed below. ;The fluorinated monomers (2) are prepared by conventional processes, for example by esterification reaction of acrylic or methacrylic acid with the corresponding perfluoroalkyl alcohol, in the presence of an acid catalyst such as sulfuric acid or para-toluenesulfonic acid. The corresponding anhydrides and chlorides ;4 ;can also be used instead of acrylic or methacrylic acid. The monomers (1) are chosen from alkyl acrylates or methacrylates containing 51-18 carbon atoms in the alkyl group, such as: methyl acrylate, ethyl acrylate, butyl acrylate, isopropyl acrylate, or stearyl acrylate. Other non-acrylate or non-methacrylate monomers may be used, for example: styrene, alpha-methylstyrene, or alpha-cyanomethylstyrene. The composition described above is polymerized by conventional solution or bulk polymerization techniques. When polymerization is carried out in solution, the solvents used are aliphatic hydrocarbons such as heptane, or *

Aromatic hydrocarbons such as benzene, toluene, xylene; ketones such as acetone, methylethyl ketone, methylisobutyl ketone; esters such as butyl or ethyl acetate; ethers such as dimethyl or diethyl ether, ethylene glycol, dipropyl or dibutyl ether; halogenated hydrocarbons such as 1,1,1-trichloroethane, trichloroethylene, perchloroethylene; fluorinated solvents such as Freon 113; or other solvents such as acetonitrile, n-methylpyrolidone or mixtures of these solvents.

20. The polymerization temperature varies between room temperature and the boiling point of the reaction mixture, preferably between 80° and 100°C. The radical initiators used are azo compounds such as azo-bisisobutyronitrile (AIBN), 1,1'-azo-bis(cyanocyclohexane), azodicarbonamide, or peroxides such as ditert-butyl peroxide, peroxide acetates such as 25-tert-butyl peracetate, or benzoates such as tert-butyl perbenzoate, or octoates such as tert-butyl peroctoate. The amount of initiator used varies from 0.2% to 2%, preferably from 0.4% to 1% relative to the total weight of the monomers. The reaction can also take place under UV irradiation in the presence of photoinitiators such as benzophenone.

30 The weight of the polymers obtained is determined by gel permeation chromatography using polystyrene as a standard and THF as an eluent. Average weights ranging from 6000 to 100,000 are obtained.

Once the polymer is obtained, it can be deposited as is without being isolated from the environment.

5

In the reaction process, the polymerization solvent is used as the deposition solvent, or isolated from the reaction medium by precipitation in a solvent such as methanol, and then deposited neat or in solution in a solvent other than the polymerization solvent. When the polymer is deposited in solution, it is possible to add various additives to the formulation, such as UV stabilizers like benzophenones, antioxidants, thixotropic agents, pigments, etc.

The formulation is thus deposited in one or more layers using conventional coating methods such as brush, paintbrush, spray gun, or electrodeposition. It is then dried at a temperature between 80° and 150°C, preferably between 80° and 120°C, for 8 to 48 hours.

The present invention will be better understood with the aid of the following additional description. The following examples illustrate the present invention without, however, limiting it.

15 Example 1:

In a reactor equipped with a stirrer, a condenser, and a thermometer, lg is placed

(9.61 mmol) of styrene and 0.5 g (0.961 mmol) of CgFi-y(CH2)20COCH=CH2 (Al), 2 ml of freshly distilled acetonitrile and 0.0069 g (0.042 mmol) of AIBN. The mixture is purged with nitrogen and then heated at 80°C for 16 hours.

20. Methanol is then added until the polymer precipitates. This polymer is subjected to several washing/centrifugation cycles and then dried under reduced pressure. A solution of this polymer in a fluorinated solvent such as forane 113 at a concentration of 0.15 g/ml is deposited onto PET. The resulting film is dried at 80°C for 16 hours. This yields a transparent film with a thickness of 25 µm on the order of 1.5 (j). The contact angles, θ, at the surface of this film are measured using water and hexadecane as wetting solvents. The surface tensions and the polar and nonpolar components of the two solvents are used to calculate the surface energy using the Owens, Wendt, and Fowkes method. The results obtained are as follows:

30 0EAU = 111°; ©HEXADECANE = 65°; Surface energy (mN/m) = 14.57.

Example 2:

In the formulation described in example 1, the Al monomer is replaced by 0.052g

6

(0.0961mmol) of monomer A2 of general formula: CgF^C^^OCOCH-CH/?.

The polymerization, processing, and deposition conditions are maintained identically to those of Example 1. The following results are obtained:

©EAU = 107°; 0HEXADECANE = 59°; Surface energy (mN/m) = 14.24.

5

Example 3:

In a reactor equipped with a stirrer, a condenser, and a thermometer, lg is placed

(7.81mmol) of butyl acrylate and 0.4 g (0.781mmol) of CgF^Œ^OCOCH^CI^

(Al), 2 ml of freshly distilled acetonitrile and 0.007 g (0.042 mmol) of AIBN. The mixture is purged with nitrogen and then heated at 80°C for 12 hours.

Methanol is then added until the polymer precipitates. This polymer is subjected to several washing/centrifugation cycles and then dried under reduced pressure. A solution of this polymer in a fluorinated solvent such as forane 113 at a concentration of 0.15 g/ml is deposited onto PET. The resulting film is dried at 15–120°C for 24–48 hours. This yields a transparent film with a thickness of approximately 1.5 µm. The contact angles of this film are measured using water, CH2I2, and hexadecane as wetting solvents. The surface tensions and the polar and nonpolar components of the first two solvents are used to calculate the surface energy using the Owens, Wendt, and Fowkes method. The results obtained are as follows:

0EAU = 119°; 0CH2I2 = 111°; 0HEXADECANE = 99°; Surface energy (mN/m) = 6.00. Example 4:

In the formulation described in Example 1, the Al monomer is replaced by 0.045 g 25 (0.0781 mmol) of A2 monomer, with the general formula: CgFi7(CH2)60C0CH=CH2. The polymerization, processing, and deposition conditions are kept identical. The contact angles, θ, of the dry film obtained are measured using water, CH2I2, and hexadecane as wetting solvents. The surface tensions and the polar and nonpolar components of the first two solvents are used to calculate the surface energy θ using the Owens, Wendt, and Fowkes method. The results obtained are:

0water = 123°; 0CH2I2 = 103°; 9hexadecane = 73°; Surface energy (mN/m) = 7.6.

7

Claims (7)

DEMANDS 1) Varnishes obtained by radical polymerization of a composition containing [A] from 10 to 70% by weight relative to the total composition of a mixture containing: (a)- from 40 to 99% by weight relative to [A], of styrene or of an acrylate or methacrylate type monomer having 1 to 18 carbon atoms in the alkyl group, (b)- from 0.1 to 60% by weight relative to [A] of fluorinated monomer of general formula: in which: ♦ R/- denotes a linear or branched perfluoroalkyl chain CmF2m+i (m = there ♦R denotes a hydrogen atom or a linear or branched alkyl group containing 1 to 4 carbon atoms; ♦n varies from 1 to 15; (c)- from 0.2 to 2% by weight relative to [A] of radical initiator; [B] from 0 to 80% by weight relative to the total composition, of polymerization solvent. 2) Compositions according to claim (1), wherein Rp = C4F8, C6F13 3) Compositions according to claim (1), wherein n = 2, 4 and 6. 4) Compositions according to claim (1) containing 65 to 95% of monomer according to (a), 3 to 35% of fluorinated monomer (b), 0.4 to 1% of at least one radical initiator and 30 to 60% solvent. 5) Use of the varnishes according to claim (1) as coatings by weight: 22) and CgFiv- & 8 anti-graffiti, anti-fouling, anti-sticking, and hydrophobic and oleophobic surface treatments of organic polymer type. 6) Application of the varnishes obtained according to claim (1), onto the substrate to be protected, either pure or in solution in the polymerization solvent or in a solvent other than the polymerization solvent 7) Varnish according to claims 1 to 6 characterized in that the support to be protected is an organic plastic in particular polyethylene, polyvinyl chloride (PVC), polyacrylates, polymethacrylates, polypropylene, polyamides, polyurethanes, acrylonitrile-butadiene-styrene (ABS), saturated or unsaturated polyesters such as polyethylene terephthalate (PET), polycarbonates, polyacrylamides, Teflon (PTFE), polysiloxanes, polysaccharides.