WO2004024790A1

WO2004024790A1 - 'copolymer, coating composition comprising the same, process for applying it'

Info

Publication number: WO2004024790A1
Application number: PCT/IB2002/003817
Authority: WO
Inventors: Roberta Bongiovanni; Marco Sangermano
Original assignee: Esetec Incorporated
Priority date: 2002-09-16
Filing date: 2002-09-16
Publication date: 2004-03-25
Also published as: AU2002330365A1

Abstract

A copolymer obtainable by a process comprising the phase of mixing a cationically polymerizable monomer and a fluorinated alcohol, wherein the quantity of said cationically polymerizable monomer is at least 90% (w/w) and that the quantity of said fluorinated alcohol is from 0.01 to 5% (w/w) and a coating composition comprising the above copolymer. A process applying the above copolymer comprising the steps of a) mixing a quantity of cationically polymerizable monomer of at least 90% (w/w) and a quantity of a fluorinated alcohol from 0.01 to 5% (w/w) , b) applying the product obtained in phase a) onto a substrate and c) hardening the product of phase b) and a coating obtainable by the above procedure.

Description

"Copolymer, coating composition comprising the same, process for applying it" DESCRIPTION

The present invention refers to a copolymer and a coating composition comprising the same.

The present invention also refers to a process for applying said coating composition and the coating thus obtained.

More in particular, the present invention refers to a copolymer formed by the reaction of a cationically polymerizable monomer with a fluorinated alcohol, suitable to coat high surface energy substrates.

In the course of the present description and claims, the term "high surface energy substrate" is intended to mean a substrate having a surface tension of at least 50 mN/m, preferably higher than 100 mN/m.

Typical examples of these substrates are metals, glass, ceramic materials, wood, paper, and some appropriately modified plastic materials. In the course of the present description and claims, the term "fluorinated alcohol" refers to alcohols, diols and polyols.

In the course of the present description and claims, the term "cationically polymerizable monomer" means - monomers such as, for example, epoxide, alkenylether, styrene and styrene derivatives, oxazoline, cyclic ether and acetal .

A coating material for high surface energy substrates must however simultaneously possess all the following characteristics :

- have excellent adhesion with respect to said high surface energy substrates so as to remain attached to them;

- be endowed- with repellent properties with respect to liquids, such as for example, water;

- have anti-fingerprint properties, that is, being endowed with non-wetting properties with respect to, for example, dyes, pigments, inks, varnishes, oils, fats and adhesives; - have good mechanical properties so as to resist external mechanical stresses, such as friction;

- be able to maintain said characteristics also when in the form of a coating with very low thickness (< 1 μm) ; - be endowed with antifouling properties that is, able to not favor the growth of bacteria and fungi; and

- be applied to the substrate of interest through a simple process .

The problem underlying the present invention is therefore to provide a coating that simultaneously possesses all of the physical-chemical characteristics illustrated above.

This problem is solved by a copolymer obtainable by the process comprising the step of mixing a cationically polymerizable monomer and a fluorinated alcohol, characterized by the fact that the quantity of said cationically polymerizable monomer is at least 90% (w/w) and that the quantity of said fluorinated alcohol, is from 0.01 to 5% (w/w) . Preferably, the quantity of said cationically polymerizable monomer is from 95 to 99.9% (w/w) .

Preferably, the quantity of said fluorinated alcohol monomer is from 0.01 to 1.5% (w/w) .

Preferred examples of said cationically polymerizable monomer are selected from epoxide, alkenylether, styrene and styrene derivatives, oxazoline, cyclic ether and acetal, even more preferably epoxide and alkenylether.

Advantageously, said epoxide is of a cycloaliphatic type, still more advantageously it comprises of at least one 3,4-epoxycyclohexyl group.

Preferred examples of said cycloaliphatic epoxide are those selected from 3,4-epoxycyclohexylmethyl-3' ,4' - epoxycyclohexyl carboxylate, bis (3 , 4-epoxycyclohexyl) adipate, vinyl cyclohexane monoxide and mixtures thereof. Advantageously, said fluorinated alcohol is linear or branched aliphatic, saturated or unsaturated in type, having at least 4 carbon atoms, still more advantageously, it has from 4 to 30 carbon atoms. Advantageously, said fluorinated alcohol is of aliphatic, linear, saturated type having from 8 to 10 carbon atoms.

Preferred examples of said fluorinated alcohol are ' those selected from l,l,l,3,3,3-hexafluoro-2-propanol, IH, IH-perfluoro-1-nonanol, IH, IH-perfluoro-1-dodecanol and mixtures thereof.

The fluorinated alcohol monomer of the present invention can have as substitutes a heteroatom selected from O, N, S, a halogen or combinations thereof. Advantageously, the copolymer of the present invention presents a wettability with respect to a high surface energy substrate equal to that of the cationically polymerizable monomer used to form said copolymer and a wettability with respect to a liquid or powder substance lower than that of the cationically polymerizable monomer used to form said copolymer.

Still more advantageously, said copolymer presents a wettability, measured by contact angle, with respect to a liquid powder substance greater than 80°. Still more advantageously, said copolymer presents a wettability, measured by contact angle, with respect to a liquid or powder substance between 80° and 120°.

Preferred examples of said substance in the liquid state are those selected from water, oils, organic solvents, inks, varnishes, fats and adhesives.

Preferred examples- of said substance in powder form are those selected from atmospheric dust, pigments, dyes, bacteria and fungi .

The copolymer of the present invention can be used in different fields such as, for example, to form coatings for articles destined to come in contact with liquids such as, for example, device destined to come in contact with sea water such as submarine and boat elements such as keel, mechanical parts for immersion in solvents, to form coatings for articles destined to come in contact with powders such as, for example, aerospace equipment, aircrafts, cars, trams, trains, to form coatings for household and building articles such as furniture, appliances, air conditioning filters and ducts, to form release coatings such as, for example, coatings destined to come in contact with adhesive elements and varnishes in general and in particular those of a sanitizing type "hygienic coating" and antifouling.

Therefore a second object of the present invention is to provide a coating composition comprising the copolymer of the present invention.

Said coating composition may contain conventional type additives, in addition to the copolymer of the present invention. Typical examples of these additives are crosslinking agents, sensitizing agents, pigments, solvents, dispersants, stabilizing agents, antiflocculants, emulsifiers, viscosity modifiers, humidifiers, antifoaming agents, diluents, surfactants, plasticisers, drying agents, thickeners, waxes, charges, hardening agents and dilating agents .

Typical examples of cross-linking agents are the photo-initiators such as, for example, the onium salts and catalysts such as, for example, amines and anhydrides .

Preferably, the quantity of said photo-initiators or catalysts in the composition, of the present invention is from 0.5 to 3.5% (w/w), still more preferably, they are from 1.5 to 2.5% (w/w). Typical examples of pigments suitable for use in the coating composition of the present invention are natural, synthetic, organic and inorganic conventional pigments suitable for the preparation of colored coating products.

Typical examples of suitable solvents are acetone, alcohols, dimethylformamide and glycols. Said coating composition according to the present invention can be prepared by conventional type technique which comprise the mixing, the granulation and the compression, when necessary, or various mixings and dissolutions of the ingredients according to whatever is most appropriate to obtain the desired product.

The copolymer of the present invention can be applied to the substrate of interest as such.

Therefore, a third object of the present invention is to provide a process for applying the copolymer comprising the steps a) mixing a quantity of cationically polymerizable monomer of at least 90% (w/w) and a quantity of fluorinated alcohol from 0.01 to 5% (w/w), b) applying the product obtained in phase a) to a substrate and c) hardening the product of phase b) .

Preferably, said phase b) is carried out by the method selected from roller coating, dip coating, curtain coating, brush, flow coating, spatula, spin coating, spray coating, vacuum coating and by extrusion. The product obtained in phase a) can be in the form of a liquid, slurry or powder, preferably it is in the form of a liquid or slurry.

Preferably, said phase c) is carried out by irradiation. Still more preferably, said irradiation is an electromagnetic radiation or an ionizing radiation. Advantageously, said electromagnetic radiation has a wavelength from 100 to 800 nm, preferably from 200 to 450 nm.

Advantageously, said ionizing radiation is carried out through electron bombardment .

Said phase c) can also be carried out through thermal heating. Preferably, said heating is performed at a temperature between room temperature and 250°C.

The coating obtained by the process described above has a thickness of from 0.1 to 500 μm, preferably of from 1 to 100 μm, even more preferably of from 1 to 30 μm.

From what stated above, the advantages of the copolymer of the present invention are immediately clear.

A first advantage is that the copolymer of the present invention possesses a wettability with respect to high surface energy substrates equal to that of the cationically polymerizable monomer used- to. form the copolymer and a wettability with respect to a liquid or powder substance lower than that of the cationically polymerizable monomer used to form said copolymer. That allows to obtain a copolymer possessing excellent adhesion with respect to the high surface energy substrates and being endowed with repellent properties with respect to liquid or powder substances. These surface properties confer thus to the copolymer of the present invention a wide versatility of use. It can in fact be used, for example, in varnishes, coatings endowed with antigraffiti properties, in coatings for articles destined to come in contact with liquids such as, for example, device destined to come in contact with sea water such as submarine and boat elements such as keel, mechanical parts for immersion in solvents, to form coatings for articles destined to come in contact with powders such as, for example, aerospace equipment, aircrafts, cars, trams, trains, to form coatings for household and building articles such as furniture, appliances, air conditioning filters and ducts, to form release coatings such as, for example, coatings destined to come in contact with adhesive elements and varnishes in general and in particular those of a sanitizing type "hygienic coating" and antifouling.

A third advantage is that the copolymer of the present invention retains these properties even in coatings with very low thickness such as < 1 μm. A fourth advantage is that the copolymer of the present invention is prepared in situ by a simple procedure, which adopts traditional type techniques.

The following examples serve to illustrate the present invention without limiting it in any way. Example 1

3,4 - epoxycyclohexilmethyl - 3 ',4' epoxycyclohexil carboxylate (CE) , Ph₃S⁺PF6^" (2% w/w with respect to CE) and IH, IH - perfluoro -1- nonanol

CF₃(CF₂)₇CH₂OH (FI) were mixed.

The Fl/CE weight ratios used in this Example are shown in Table 1.

Table 1

The obtained mixture were coated on a glass substrate with a wire-wound calibrated bar up to a thickness of the coating . of 100 μm and then- photocured with a D-lamp with a LTV emission spectrum typical for a D Fusion lamp of from 200 to 450 nm having a maximum peak particularly accentuated between 360 and 390 nm (Figure 1) , intensity = 250 mWcπf² (measured with EIT Power Map) , maximum irradiation time = 8 sec.

The main characteristics of the obtained coatings are reported in the Tables- 2a and 2b. Table 2a

a) measured by FTIR monitoring the decrease of the epoxy group band at 980 cm^"1, 24 hours after the curing; b) minimum time required for having a non-tacky surface; c) weight reduction of the sample after 24 hours extraction with chloroform at room temperature; d) measured by dynamic-mechanical test analysis DMTA, as the temperature corresponding to the maximum of the tan δ curve.

Analogous results were obtained when the above mixture were coated on a metal substrate.

Table 2b

e) measured by ASTM D3359-83, glass was used as a substrate; f) measured by ASTM3363-80; g) number of methylethylketone (MEK) double rubs required for damaging the film.

The wettability of the coatings is shown in Table 3. The above coatings were peeled off from the substrate labeling the surface in contact with the substrate as substrate side and the opposite side as airside. The measures of the contact angle were carried out with the sessile drop method ("S.IVu Polymer Interface and Adhesion" , M.Dekker, New York, 1982, Chapter 4) . The results are shown in the following Table 3.

Table 3

On the above coatings graffiti cleaning tests were carried out. The graffiti were made with a glass graphic pen STABILO. The results are shown in the following Table 4.

Table 4

Yes = clean surface, no shade; no = shade

Example 2 As described in the above Example 1 but using IH, IH - perfluoro -1- dodecanol CF₃ (CF₂) ι₀CH₂OH (F2) in place of IH, IH - perfluoro -1- nonanol CF₃ (CF₂) ₇CH₂OH.

The F2/CE weight ratios are shown in Table 5.

Table 5

The main characteristics of the above coatings on the glass substrate are shown in Tables 6a and 6b. Table 6a

Table 6b

The wettability of the coatings is shown in Table 7

Table 7

On the above coatings graffiti cleaning tests were carried out. The graffiti were made with a glass graphic pen STABILO. The results are shown in Table 8.

Table 8

Example 3 As described in the above Example 2 but using 1,4 - cyclohexandimethanoldiglycidyl ether (DGE) in place of 3,4 - epoxycyclohexilmethyl - 3 ',4' - epoxycyclohexil carboxylate (CE) .

The F2/DGE weight ratios are shown in Table 9.

Table 9

The main characteristics of the above coatings on the glass substrate are shown in Tables 10a and 10b.

Table 10a

Coating No. Curing Tack free Gel content Glass

Analogous results were obtained when the above mixture were coated on a metal substrate .

Table 10b

The wettability of the above coatings is shown in Table 11.

Table 11

On the above coatings graffiti cleaning tests were carried out. The graffiti were made with a glass graphic pen STABILO. The results are shown in Table 12.

Table 12

Example 4

As described in the above Example 2 but using 1 -bis

- (4-vinyloxybutyl) - isophtalate (VE) in place of 3,4 - epoxycyclohexilmethyl - 3 ',4' - epoxycyclohexyl carboxylate (CE) .

The F2/VE weight ratios are shown in Table 13.

Table 13

The main characteristics of the above coatings on the glass substrate are shown in Tables 14a and 14b.

Table 14a

Table 14b

The wettability of the above coatings is shown in

Table 15 Table 15

On the above coatings graffiti cleaning tests were carried out. The graffiti were made with a glass graphic pen STABILO. The results are shown in Table 16.

Table 16

Claims

1. A copolymer obtainable by a process comprising the step of mixing a cationically polymerizable monomer and a fluorinated alcohol, characterized by the fact that the quantity of said cationically polymerizable monomer is at least 90% (w/w) and that the quantity of said fluorinated alcohol is from 0.01 to 5% (w/w).

2. The copolymer according to claim 1, wherein the quantity of said cationically polymerizable monomer is from 95 to 99.9% (w/w).

3. The copolymer according to claim 1, wherein the quantity of said fluorinated alcohol is from 0.01 to 1.5% (w/w) . . The copolymer according to claim 1 , wherein said cationically polymerizable monomer is selected from epoxide, alkenylether, styrene and styrene derivatives, oxazoline, cyclic ether and acetal .

5. The copolymer according to claim 4 , wherein said epoxide is of a cycloaliphatic type. 6. The copolymer according to claim 5 , wherein cycloaliphatic epoxide comprises at least one 3,4- epoxycyclohexyl group.

7. The copolymer according to claim 6 , wherein said cycloaliphatic epoxide is selected from 3,4- epoxycyclohexylmethyl-3' , 4' -epoxycyclohexyl carboxylate, bis (3, 4-epoxycyclohexyl) adipate, vinyl cyclohexane monoxide and mixtures thereof.

8. The copolymer according to claim 1 , wherein said fluorinated alcohol monomer is of an aliphatic, linear or branched, saturated or unsaturated type, having at least 4 carbon atoms, preferably from 4 to 30 carbon atoms .

9. The copolymer according to claim 8 , wherein said fluorinated alcohol is an aliphatic, linear, saturated type.

10. The copolymer according to claim 9, wherein said fluorinated alcohol has from 8 to 10 carbon atoms.

11. The copolymer according to claim 9, wherein said fluorinated alcohol is selected from 1,1,1,3,3,3- hexafluoro-2-propanol, IH, IH-perfluoro-1-nonanol, IH, IH-perfluoro-1-dodecanol and mixtures thereof.

12. The copolymer according to the claims from 1 to 11, wherein said copolymer presents a wettability with respect to a high energy substrate equal to that of the cationically polymerizable monomer used to form said copolymer and a wettability with respect to a liquid or powder substance lower to that of the cationically polymerizable monomer used to form said copolymer.

13. The copolymer according to claim 12 , wherein said copolymer presents a wettability, measured by contact angle, with respect to a liquid state or powder substance, greater than 80°.

14. The copolymer according to claim 13 , wherein said copolymer presents a wettability, measured by contact angle, with respect to a liquid or powder substance, between 80° and 120°.

15. The copolymer according to claim 14, wherein said liquid substance is selected from water, oils, organic solvents, inks, varnishes, fats and adhesives. 16. The copolymer according to claim 15, wherein said substance in the powder state is selected from atmospheric dust, pigments, dyes, bacteria and fungi.

17. A coating composition comprising the copolymer described in the claims from 1 to 16. 18. A process applying the copolymer as described in the claims from 1 to 16, said process comprising the steps of a) mixing a quantity of cationically polymerizable monomer of at least 90% (w/w) and a quantity of a fluorinated alcohol from 0.01 to 5% (w/w), b) applying the product obtained in phase a) onto a substrate and c) hardening the product of phase b) .

19. The process according to claim 18, wherein said phase b) is carried out using the method selected from roller coating, deep coating, curtain coating, brush, flow coating, spatula, spin coating, spray coating, vacuum coating and by extrusion.

20. The process according to claim 18, wherein said phase c) is carried out by irradiation.

21. The process according to claim 20, wherein said irradiation is an electromagnetic radiation or an ionizing radiation.

22. The process according to claim 21, wherein said electromagnetic radiation has a wavelength from 100 to 800 nm. 23. The process according to claim 18, wherein said phase c) is carried out by thermal heating.

24. The process according to claim 23, wherein said thermal heating occurs at a temperature between room temperature and 250°C. 25. A coating obtainable by the procedure as described in the claims from 18 to 24.

26. The coating according to claim 25, wherein said coating has a thickness of from 0.1 to 500 μm.

27. The coating according to claim 26, wherein said coating has a thickness of from 1 to 100 μm.

28. The coating according to claim 27, wherein said coating has a thickness of from 1 to 30 μm.