WATER-BASED COMPOSITION COMPRISING A FLUORINATED POLYMER

Abstract

This invention provides for a composition particularly useful in a method comprising applying the composition to a surface to be lubricated, said composition comprising: at least one polymer (P) comprising a partially or fully fluorinated, straight or branched, polyoxyalkylene chain (R.sub.f) having two chain ends, wherein one or both chain end(s) bear(s) a hydroxy-, alkoxy- or acyl-oxy-terminated polyoxyalkylene chain free from fluorine atoms (R.sub.a), said chain comprising from 4 to 50 fluorine-free oxyalkylene units, said units being the same or different from one another and being selected from —CH.sub.2CH.sub.2O— and —CH.sub.2CH(O)O—, wherein J is independently straight or branched alkyl or aryl, preferably methyl, ethyl or phenyl and water.

Claims

1. A composition comprising: at least one polymer (P) comprising a partially or fully fluorinated, straight or branched, polyoxyalkylene chain (R.sub.f) having two chain ends, wherein one or both chain end(s) bear(s) a hydroxy-, alkoxy- or acyloxy-terminated polyoxyalkylene chain free from fluorine atoms (R.sub.a), said chain comprising from 4 to 50 fluorine-free oxyalkylene units, said units being the same or different from one another and being selected from —CH.sub.2CH.sub.2O— and —CH.sub.2CH(J)O—, wherein J is independently straight or branched alkyl or aryl, and water.

2. The composition according to claim 1 wherein polymer (P) complies with formula (I) below:
A-O—R.sub.f—(CF.sub.2).sub.x—CFZ—CH.sub.2—O—R.sub.a   (I) wherein: R.sub.f is a (per)fluoropolyoxyalkylene chain having an average number molecular weight M.sub.n ranging from 100 to 8,000 and comprising repeating units, which may be equal to or different from one another, selected from: (i) —CFXO—, wherein X is F or CF.sub.3, (ii) —CFXCFXO—, wherein X, equal or different at each occurrence, is F or CF.sub.3, with the proviso that at least one of X is F; (iii) —CF.sub.2CF.sub.2CW.sub.2O—, wherein each of W, equal or different from each other, are F, Cl, H; (iv) —CF.sub.2CF.sub.2CF.sub.2CF.sub.2O—; (v) —(CF.sub.2).sub.j—CFZ—O— wherein j is an integer from 0 to 3 and Z is a group of general formula —OR.sub.f′T, wherein R.sub.f′ is a fluoropolyoxyalkene chain comprising a number of repeating units from 0 to 10, said recurring units being selected from chosen among the followings: —CFXO—, —CF.sub.2CFXO—, —CF.sub.2CF.sub.2CF.sub.2O—, —CF.sub.2CF.sub.2CF.sub.2CF.sub.2O—, with each of each of X being independently F or CF.sub.3 and T being a C.sub.1-C.sub.3 perfluoroalkyl Z is fluorine or CF.sub.3; x is 0 or 1, with the proviso that, when x is 1, Z is F; A is —(CF.sub.2).sub.x—CFZ—CH.sub.2—O—R.sub.a, wherein x and Z are as defined above, or is a straight or branched C.sub.1-C.sub.4 perfluoroalkyl group wherein one fluorine atom is optionally can be substituted by one chlorine atom or one hydrogen atom, with the proviso that, if chlorine is present in group A, it is in a molar amount lower than 2% with respect to the overall amount of end groups and R.sub.a is a hydroxy-, alkoxy- or acyloxy-terminated polyoxyalkylene chain free from fluorine atoms (chain R.sub.a), said chain comprising from 4 to 50 fluorine-free oxyalkylene units, said units being the same or different from one another and being selected from —CH.sub.2CH.sub.2O— and —CH.sub.2CH(J)O—, wherein J is as defined in claim 1.

3. The composition according to claim 1, wherein chain R.sub.f in polymer (P) is selected from formulae (a)-(c) here below:
(CF.sub.2O).sub.nCF.sub.2CF.sub.2O).sub.m(CF.sub.2CF.sub.2CF.sub.2O).sub.p(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O).sub.q—  (a) wherein m, n, p, q are selected from 0 and integers such that chain R.sub.f meets the above number average molecular weight requirement;
—(CF.sub.2CF(CF.sub.3)O).sub.a(CF.sub.2CF.sub.2O).sub.b(CF.sub.2O).sub.c(CF(CF.sub.3)O).sub.d—  (b) wherein a, b, c, d are selected from 0 and integers selected such that chain R.sub.f meets the above number average molecular weight requirement; with the proviso that, at least one of a, c and d is not 0;
—(CF.sub.2CF(CF.sub.3)O).sub.e(CF.sub.2O).sub.f(CF(CF.sub.3)O).sub.g—  (c) wherein e, f, g are selected from 0 and integers such that chain R.sub.f meets the above number average molecular weight requirement.

4. The composition according to claim 3, wherein chain R.sub.f in polymer (P) complies with formula (a).

5. The composition according to claim 1 wherein chain R.sub.a in polymer (P) complies with formula (R.sub.a—I) below:
(R.sub.a—I)—(CH.sub.2CH.sub.2O).sub.r(CH.sub.2CH(CH.sub.3)O).sub.s(CH.sub.2CH(CH.sub.2CH.sub.3)O).sub.t(CH.sub.2CH(Ph)O).sub.nR.sup.1 wherein r, s, t and u are independently selected from 0 and a positive number, with r+s+t+u ranging from 4 to 50, and R.sup.1 is selected from hydrogen, C.sub.1-C.sub.4 straight or branched alkyl, and —C(O)R.sup.2, wherein R.sup.2 is C.sub.1-C.sub.4 straight or branched (halo)alkyl.

6. The composition according to claim 5 wherein in chain (R.sub.a—I), r is a positive number ranging from 4 to 15, s, t and u are 0 and R.sup.1 is hydrogen or methyl.

7. The composition according to claim 5 wherein, in chain (R.sub.a—I), r, t and u are 0, s is a positive number ranging from 4 to 15 and R.sup.1 is hydrogen or methyl.

8. The composition according to claim 5 wherein in chain (R.sub.a—I), t and u are 0, r+s ranges from 4 to 15 and R.sup.1 is hydrogen or methyl.

9. The composition according to claim 2, wherein polymer (P) complies with formula (I-A) below:
R.sub.a—O—CH.sub.2—CF.sub.2—O—R.sub.f—CF.sub.2—CH.sub.2—O—R.sub.a   (I-A) wherein: R.sub.a is as defined in claim 2 and R.sub.f complies with formula (a);
—(CF.sub.2O).sub.n(CF.sub.2CF.sub.2O).sub.m(CF.sub.2CF.sub.2CF.sub.2).sub.n(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O).sub.n—  (a) wherein m, n, p, q are selected from 0 and integers such that chain R.sub.f meets the above number average molecular weight requirement.

10. The composition of claim 1 which is free of surfactants.

11. The composition of claim 1 further comprising polytetrafluoroethylene.

12. A method of treating a surface which comprises applying the composition of claim 1, to the surface.

13. A method for the manufacture of a composition according to claim 11 which comprises adding a polytetrafluoroethylene aqueous colloidal dispersion to a polymer (P), wherein polymer (P) comprises a partially or fully fluorinated, straight or branched, polyoxyalkylene chain (R) having two chain ends, wherein one or both chain end(s) bear(s) a hydroxy-, alkoxy- or acyloxy- terminated polyoxyalkylene chain free from fluorine atoms (R.sub.a), said chain comprising from 4 to 50 fluorine-free oxyalkylene units, said units being the same or different from one another and being selected from —CH.sub.2CH.sub.2O— and —CH.sub.2CH(J)O—, wherein J is independently straight or branched alkyl or aryl.

14. The composition according to claim 1, wherein each occurrence of J is independently selected from methyl, ethyl and phenyl.

15. The composition according to claim 2, wherein R.sub.f has an average number molecular weight M.sub.n ranging from 300 to 6,000,

16. The composition according to claim 2, wherein R.sub.f has an average number molecular weight M.sub.n ranging from 800 to 3,000.

17. The composition according to claim 3, wherein: (a) when m is other than 0, the m/n ratio is between 0.1 and 20 and when (m+n) is other than 0, (p+q)/(m+n) is between 0 and 0.2; (b) when b is other than 0, a/b is between 0.1 and 10 and when (a+b) is different from 0 (c+d)/(a+b) is between 0.01 and 0.5; and (c) when e is other than 0, (f+g)/e is between 0.01 and 0.5.

18. The composition according to claim 5, wherein r+s+t+u ranges from 4 to 15.

19. The composition according to claim 9, wherein, when m is other than 0, the m/n ratio is between 0.1 and 20 and wherein when (m+n) is other than 0, (p+q)/(m+n) is between 0 and 0.2.

Description

EXAMPLE 1

Measurements of Kinematic Viscosity, Resistance to Wear and Resistance to Extreme Pressure of the Test PFPE-PAG

[0124] The tests were carried out as indicated in the “Material and Methods” section. The following results were obtained: Kinematic viscosity at 20° C.=2154 cSt, at 40° C.=622 cSt and at 100° C.=54 cSt, with a corresponding viscosity index equal to 148.

[0125] Wear on sample: the measured wear in the four-ball test was 0.48±0.04 mm.

[0126] The PFPE-PAG was also analysed under extreme pressure conditions according to the aforementioned ASTM D7421, under the following operative conditions: [0127] temperature: 110° C. (kinematic viscosity of the sample oil at this temperature was 40 cSt); [0128] stroke: 2 mm [0129] frequency: 50 Hz [0130] Pre-load: 50 N for 30″ [0131] Load: 100 N for 15′ and increase of 100 N each 2′ up to 2000 N.

[0132] The results showed that no seizure occurred at the final load of 2000 N.

EXAMPLE 2

Stability of a Water Solution of a PFPE-PAG and Evaluation of the Coefficient of Friction

[0133] A solution at 5% by wt. in water was prepared by stirring 25 g of the test PFPE-PAG in 475 g of water. After stirring, the solution appeared clear and transparent. No sediments or phase separation was observed (t=0 clear 1 phase; checked also at t=24 h clear 1 phase and t=120 h clear 1 phase).

[0134] This solution was sprayed onto polycarbonate slabs, according to the procedure described above.

[0135] A Coefficient of Friction (CoF) test according to ASTM D1894 was carried out and provided the following results: [0136] Static CoF =0.106±0.004 [0137] Dynamic CoF =0.099±0.034

EXAMPLE 3

Comparative Example

[0138] Example 2 was repeated using pure water only (100% water). The following results were obtained: [0139] Static CoF=0.172±0.084 [0140] Dynamic CoF=0.175±0.099

[0141] Example 2 demonstrates that the PFPE-PAG is completely soluble in water without using any other surfactant.

[0142] A comparison between Example 2 and Example 3 demonstrated that a very thin film of a PFPE-PAG according to the present invention was deposited and that it strongly reduced the CoF of the treated plastic of about 40% with respect to untreated plastic.

EXAMPLE 4

Measurement of the CoF on Polycarbonate Slabs Coated with a PFPE-PAG

[0143] A solution at 10% by wt. in water and isopropyl alcohol was prepared by stirring 50 g of the test PFPE-PAG in 445 g water and 5 g isopropyl alcohol. After stirring, the solution appeared clear and transparent. No sediments or phase separation was observed (t =0 clear 1 phase; checked also at t=24 h clear 1 phase and t=120 h clear 1 phase).

[0144] Polycarbonate slabs, prepared according to the procedure described above, were dipped into the solution.

[0145] A Coefficient of Friction (CoF) test according to ASTM D1894 was carried out and provided the following results: [0146] static CoF=0.155±0.032; [0147] dynamic CoF=0.049±0.013

EXAMPLE 5

Comparative Example

Measurement of the CoF on polycarbonate slabs coated with a polyoxyalkylene glycol

[0148] A solution at 10% by wt. in water and isopropyl alcohol was prepared by stirring 50 g of polyoxyalkylene glycol PEG 2000 (Sigma Aldrich) in 445 g water and 5 g isopropyl alcohol. After stirring, the solution appeared clear and transparent. No sediments or phase separation was observed (t=0 clear 1 phase; checked also at t=24 h clear 1 phase and t=120 h clear 1 phase).

[0149] Polycarbonate slabs, prepared according to the procedure described above were dipped into the solution.

[0150] A Coefficient of Friction (CoF) test according to ASTM D1894 was carried out and provided the following results: [0151] static CoF=0.352±0.238 [0152] dynamic CoF=0.191±0.111

[0153] It stems from Examples 4 and 5 that the PFPE-PAG used in accordance with the invention has a remarkably lower CoF than a polyoxyalkylene glycol.

EXAMPLE 6

Preparation of a Water-Based Composition Comprising a PFPE-PAG and a PTFE Latex

[0154] Aliquots of Algoflon® D1614F PTFE aqueous colloidal dispersion (total amount 15 g) were added to 36 g of the test PFPE-PAG contained in a beaker, under magnetic stirring on a hotplate, at the temperature of 50° C.; a grease-like composition was obtained.

[0155] The measured NLGI grade of the composition was 3, while the CoF and friction test gave the following results:

[0156] CoF.sub.end=0.119 (coefficient of friction at the end of the test)

[0157] Wear (mm) 1.08±0.04.

[0158] It was observed that the CoF remained constant during at values ranging from 0.10 to 0.13.