PTFE-based aqueous dispersions

Abstract

Compositions based on PTFE, homopolymer or modified, comprising for 100 parts of the component 1) PTFE: 1) an aqueous nanodispersion of said homopolymer or modified PTFE, having a primary particle diameter from 5 to 100 nm; 2) from 3 to 45 parts by weight of a surfactant or surfactant mixtures; 3) from 0.2 to 20 parts by weight of an organic or inorganic sequestrant, and optionally: 4) from 0 to 60 parts by weight of a solid lubricating compound.

1 . Compositions based on PTFE, homopolymer or modified, comprising for 100 parts of the component 1) PTFE: 
 1) an aqueous nanodispersion, or latex, of said homopolymer or modified PTFE, having a primary particle diameter from 5 to 100 nm;    2) from 3 to 45 parts by weight of a surfactant or surfactant mixtures;    3) from 0.2 to 20 parts by weight of an organic or inorganic sequestrant capable to give bi- or poly-coordination bands, which forms with metal ions soluble complexes and prevents from forming insoluble salts of said metals; and optionally: 
 4) from 0 to 60 parts by weight of a solid lubricating compound.  
   
     
     
         2 . Compositions according to  claim 1 , wherein the nanoemulsions of the component 1) PTFE are selected from the following classes: 
 homopolymer PTFE nanoemulsions;    modified PTFE nanoemulsions, i.e. TFE copolymers with one or more comonomers, containing at least one unsaturation of ethylene type, in an amount up to 6% molar based on the polymer.    
     
     
         3 . Compositions according to  claim 2 , wherein the comonomers used to prepare the modified PTFE of the aqueous dispersions component 1), are both of hydrogenated and fluorinated type.  
     
     
         4 . Compositions according to  claim 3 , wherein the hydrogenated comonomers are selected from the following: ethylene, propylene, acrylic monomers, selected from methyl(meth)acrylate, (meth)acrylic acid, butylacrylate, hydroxyethylhexylacrylate, styrene monomers.  
     
     
         5 . Compositions according to  claim 3 , wherein the fluorinated comonomers are selected from: 
 C 3 -C 8  perfluoroolefins;    C 2 -C 8  hydrogenated fluoroolefins CH 2═CH—R   f  perfluoroalkylethylene, wherein R f  is a C 1 -C 6  perfluoroalkyl;    C 2 -C 8  chloro- and/or bromo- and/or iodo-fluoroolefins;    CF 2 ═CFOR A   f  (perfluoroalkylvinylethers (PAVE), wherein R f  is a C 1 -C 6  (per)fluoroalkyl as above;    CF 2 =CFOX I  (per)fluoro-oxyalkylvinylethers, wherein X I  is a C 1 -C 12  alkyl, or a C 1 -C 12  oxyalkyl, or a C 1 -C 12  (per)fluoro-oxyalkyl having one or more ether groups fluorodioxoles.    
     
     
         6 . Compositions according to  claim 5 , wherein the comonomers are selected from perfluoromethoxydioxoles (MDO), perfluoropropylvinylether (PPVE), perfluoromethylvinylether (PMVE), perfluoroethylvinylether (PEVE) and perfluoropropene (PFP).  
     
     
         7 . Compositions according to  claim 1 , wherein the surfactants component 2) are anionic, cationic, non ionic, hydrogenated or fluorinated.  
     
     
         8 . Compositions according to  claim 7 , wherein the non-ionic hydrogenated surfactants are obtained by reaction of ethylenoxide (EO) with the following compounds: 
 propylenoxide (polypropylenoxide);    C 8 -C 24  alcohols and aliphatic acids, both saturated and unsaturated;    primary, secondary, tertiary alkylamines wherein an alkyl is C 8 -C 24  and the other substituents are hydrogen or C 1 -C 5  linear or branched alkyl;    alkylphenols, wherein the alkyl is as defined for alkylamines;    polycyclic hydrocarbons belonging to the terpene class.    
     
     
         9 . Compositions according to  claim 8 , wherein the non-ionic hydrogenated surfactants are selected from the following: 
 polyethoxylated alkylphenols having formula:      R II —C 6 H 4 O—(CH 2 CH 2 ) pI —OH    wherein:    R II  is a saturated or unsaturated, linear or branched alkyl chain having from 8 to 10 carbon atoms, pI=8-12;    etho-propoxylated alcohols having formula:    C nI H 2nI+1 (OC 3 H 6 O) mI —(OCH 2 CH 2 ) qI OH    wherein:    nI=8-18, mI=0-30, qI= 8 -24    polyethoxylated alcohols having formula:      C nII H 2nII+1 (OCH 2 CH 2 ) mII OH    wherein NII=8-24,    mII=2-50.    
     
     
         10 . Compositions according to  claim 7 , wherein the anionic hydrogenated surfactants are selected from those having the following formula:  
         R I   A —M A X A    
       wherein: 
 R I   A  is a C 8 -C 18  aliphatic hydrocarbon radical, both saturated and unsaturated, having a linear or branched chain;  
 M A  is an acid group;  
 X A =H, NH 4 , Na, Li, K.  
 
     
     
         11 . Compositions according to  claim 7 , wherein the cationic hydrogenated surfactants are the tetraalkylammonium salts wherein at least an alkyl is C 8 -C 24  and the other substituents are hydrogen or C 1 -C 5 , linear or branched, alkyl.  
     
     
         12 . Compositions according to  claim 7 , wherein the anionic fluorinated surfactants are selected from the following:  
         T—O—R I —CFX—COOM  (IA)  
       wherein: 
 X=F, CF 3 ;  
 M=H, NH 4 , Na, Li, K;  
 T is a C 1 -C 3  (per)fluoroalkyl group, optionally containing one Cl atom; optionally one or two F atoms can be substituted by H;  
 R f  is a (per)fluoropolyoxyalkylene radical having a number average molecular weight M, in the range 200-2,000; R f  is selected in particular from the following classes:  
 (a) —(CF 2 CF(CF 3 )O) m (CFXO) n , 
 wherein m and n are integers such that the n/m ratio is in the range 0.01-0.5 and the molecular weight is within the above range;  
 
 (b) —(CF 2 CF 2 O) p (CF 2 O) q — 
 wherein p and q are integers such that the q/p ratio is in the range 0.5-2 and the molecular weight is within the above range;  
 
 (c) —(CF 2 CF(CF 3 )O) r —(CF 2 CF 2 O) s —(CFXO) t — 
 wherein r, s, and t are integers such that r+s is in the range 1-50, the t/(r+s) ratio is in the range 0.01-0.05, X is F, CF 3 , and the molecular weight is within the above range;  
 
 (d) —(CF(CF 3 )CF 2 O) u — 
 wherein u is an integer such that the molecular weight is within the above range;  
 
 (e) —(CYZ—CF 2 CF 2 O) v — 
 wherein Y and Z, equal to or different from each other, are F, Cl or H; v is an integer such that the molecular weight is within the above range;  
 
 (f) —(CF 2 CF 2 O) w — 
 w is an integer such that the molecular weight is within the above range;  
   CF 3 (CF 2 ) nT COOM  (IIA)  
 wherein nT can range from 4 to 12,  
   F—(CF 2 —CF 2 ) nV —CH 2 —CH 2 —SO 3 M  (IIIA)  
 wherein M is as above and nV ranges from 2 to 5.  
 
 
     
     
         13 . Compositions according to  claim 12 , wherein the anionic surfactants of formula (IA) are selected from the following: 
 T—O—(C 3 F 6 O) m (CF 2 O) n —CF 2 —COOM        wherein T, M, m, and n are as above.    
     
     
         14 . Compositions according to  claim 7 , wherein the non-ionic fluorinated surfactants are selected from the following:  
         CF 3 (CF 2 ) y —L—R h   (IB)  
       wherein y is an integer from 3 to 20, L and R h  are as defined below;  
         T—O—R f —L—R h   (IIB)  
       wherein; 
 R f  is selected among the above structures (a), (b), (c), (d), (e), (f);  
 L is a divalent organic group, linking group between R f  and R h , selected from —CO—NR 1 , or —CH 2 (OCH 2 CHR 2 ) a —O—, —CH 2 (OCH 2 CHR 2 ) b —O—CO—, —CH 2 O—(CH 2 ) c —CO—O—, —CH 2 —CH 2 —O—, —CH 2 —CH 2 —;  
 wherein:  
 R 1  is —H or a C 1 -C 4  alkyl;  
 R 2  is —H or a C 1 -C 2  alkyl;  
 a, b are integers from 0 to 6;  
 c is an integer from 1 to 3;  
 R h  is a radical having a polyoxyalkylene structure selected from:  
 (i) —(CH 2 CH 2 O) qI CH 2 CH 2 Z u , wherein: qI is an integer from 5 to 70; Z u  is selected between —OH, C 1 -C 4  alkoxy;  
 (ii) —(CH 2 CH 2 O) rI (CH 2 CH(CH 3 )O) sI CH 2 CHR 3 Z u , wherein: rI+sI is an integer from 5 to 70; the rI/sI ratio is in the range 0.1-10; R 3  is selected between —H and —CH 3 ; Z u  is as above;  
 T is as above.  
 
     
     
         15 . Compositions according to  claim 14 , wherein the non-ionic fluorinated surfactants are selected from the following: 
 structure (IB) compounds, wherein y=5, L=—CH 2 —CH 2 —O—, R h =—(CH 2 CH 2 O) qI CH 2 CH 2 OH wherein qI=6;    structure (IIB) compounds, wherein R f  has structure (a), T=—C 3 F 6 Cl, m and n such to give a molecular weight in the range 450-650; L=—CONH—; R h =—(CH 2 CH 2 O) qI —CH 2 CH 2 OCH 3  wherein qI=21.    
     
     
         16 . Compositions according to  claim 1 , wherein the organic or inorganic sequestrants have a functionality of acid type, selected between carboxilic or phosphonic type, in a number higher than or equal to two.  
     
     
         17 . Compositions according to  claim 16 , wherein the inorganic sequestrants are selected from polyphosphates, potassium pyrophosphate K 4 P 2 O 7 , sodium tripolyphosphate Na 5 P 3 O 10 ; those organic are selected from the group comprising amino-poly-carboxylic acids, polyhydroxymonocarboxylic acids, and phosphonates.  
     
     
         18 . Compositions according to  claim 16 , wherein the sequestrants are selected from the following: 
 (CH 2 COOH) 2 —N—CH 2 —CH 2 —N—(CH 2 COOH) 2 , ethylendiaminotetraacetic acid (EDTA);    (CH 2 COOH) 2 —N—CH 2 —CH 2 —N(CH 2 COOH)(CH 2 CH 2 OH), N-hydroxyethylethylendiaminotriacetic acid (HEDTA);    N—(CH 2 COOH) 3 , nitrilotriacetic acid (NTA);    CH 3 —CH(H 2 PO 3 ) 2 , 1-hydroxyethyliden-1,1-diphosphonic acid (HEDP);    N(CH 2 —PO 3 H 2 ) 3 , aminotrimethylenphosphonic acid (ATMP);    (H 2 O 3 P—CH 2 ) 2 —N—CH 2 —CH 2 —N(H 2 O 3 P—CH 2 ) 2 , ethylendiaminotetramethylenphosphonic acid (EDTMP);    (H 2 O 3 P—CH 2 ) 2 —N—CH 2 —CH 2 —N(CH 2 PO 3 H 2 )—CH 2 —CH 2 —N(H 2 O 3 P—CH 2 )2, diethylentriaminopentamethylenphosphonic acid (DTPMP)    (H 2 O 3 P—CH 2 ) 2 —N—(CH 2 ) 6 —N(H 2 O 3 P—CH 2 ) 2 , hexamethylendiaminotetramethylenphosphonic acid (HMDTMP).    
     
     
         19 . Compositions according to  claim 1 , wherein the optional component 4) is selected from the following: MoS 2 , WS 2  and graphite.  
     
     
         20 . Compositions according to  claim 1 , optionally further diluted with water, and added with adhesion promoters, rheological modifiers to regulate the viscosity.  
     
     
         21 . Compositions according to  claim 1 , wherein the aqueous nanodispersion, or latex, of said homopolymer or modified PTFE, has a primary particle diameter from 10 to 80 nm.  
     
     
         22 . Compositions according to  claim 1 , wherein the surfactant or surfactant mixtures is from 5 to 30 parts by weight.  
     
     
         23 . Compositions according to  claim 1 , wherein the organic or inorganic sequestrant capable to give bi- or poly-coordination bands is from 0.4 to 10 parts by weight.  
     
     
         24 . Compositions according to  claim 1 , wherein the solid lubricating compound is 0 to 50 parts by weight.  
     
     
         25 . Compositions according to  claim 1 , wherein the solid lubricating compound is selected from sulphides and selenides of the transition elements belonging to the groups VB and VIB of the Element Periodic Table, and carbon compounds as graphite and C 60  and C 70  fullerenes.  
     
     
         26 . Compositions according to  claim 1 , wherein the sulphides and selenides of the transition elements belonging to the groups VB and VIB of the Element Periodic Table are molybdenum or tungsten.  
     
     
         27 . Compositions according to  claim 2 , wherein the modified PTFE nanoemulsions are in an amount up to 1% molar.  
     
     
         28 . Compositions according to  claim 4 , wherein the styrene monomer is styrene.  
     
     
         29 . Compositions according to  claim 5 , wherein the C 2 -C 8  hydrogenated fluoroolefins are vinyl fluoride (VF), vinylidene fluoride (VDF), trifluoroethylene, or hexafluoroisobutene.  
     
     
         30 . Compositions according to  claim 5 , wherein the C 1 -C 6  perfluoroalkyl is selected from CF 3 , C 2 F 5 , and C 3 F 7 .  
     
     
         31 . Compositions according to  claim 5 , wherein the C 2 -C 8  chloro- and/or bromo- and/or iodo-fluoroolefins is chlorotrifluoroethylene (CTFE).  
     
     
         32 . Compositions according to  claim 5 , wherein the C 1 -C 12  (per)fluorooxyalkyl having one or more ether groups is perfluoro-2-propoxy-propyl.  
     
     
         33 . Compositions according to  claim 5 , wherein the fluorodioxoles are perfluorodioxoles.  
     
     
         34 . Compositions according to  claim 8 , wherein the polycyclic hydrocarbons belonging to the terpene class are β-pinene.  
     
     
         35 . Compositions according to  claim 9 , wherein NII=8-18.  
     
     
         36 . Compositions according to  claim 9 , wherein mII=2-18.  
     
     
         37 . Compositions according to  claim 10 , wherein R I   A  is a C 8 -C 18  aliphatic hydrocarbon radical, both saturated and unsaturated, having a linear or branched chain selected from the group consisting of-a oleyl, stearyl, tridecyl, lauryl, and decyl radical.  
     
     
         38 . Compositions according to  claim 10 , wherein M A  is an acid group selected from the group consisting of COO— and SO 3 —.  
     
     
         39 . Compositions according to  claim 12 , wherein T is selected from the group consisting of —CF 3 , —C 2 F 5 , —C 3 F 7 , —CF 2 Cl, —C 2 F 4 Cl, and C 3 F 6 Cl.  
     
     
         40 . Compositions according to  claim 12 , wherein M, in the range 350-1,000.  
     
     
         41 . Compositions according to  claim 14 , wherein a, b are integers from 0 to 2.  
     
     
         42 . Compositions according to  claim 14 , wherein qI is an integer from 6 to 25.  
     
     
         43 . Compositions according to  claim 14 , wherein rI+sI is an integer from 10 to  
     
     
         44 . Compositions according to  claim 14 , wherein the rI/sI ratio is in the range 0.5-5.  
     
     
         45 . Compositions according to  claim 16 , wherein carboxilic or phosphonic is two or four.  
     
     
         46 . Compositions according to  claim 17 , wherein the polyphosphate is sodium hexamethaphosphate Na 6 P 6 O 18 .  
     
     
         47 . Compositions according to  claim 17 , wherein the amino-polycarboxylic acid is gluconic acid.  
     
     
         48 . Compositions according to  claim 20 , wherein the rheological modifiers to regulate the viscosity are water-soluble polymers.  
     
     
         49 . Compositions according to  claim 5 , wherein the fluorinated comonomers are selected from hexafluoropropene (HFP).  
     
     
         50 . Compositions according to  claim 17 , wherein the amino-polycarboxylic acids are EDTA.  
     
     
         51 . Compositions according to  claim 17 , wherein the polyhydroxymonocarboxylic acids are preferably gluconic acid.  
     
     
         52 . Compositions according to  claim 23 , wherein R B   f  represents a (per)fluoropolyether chain having number average molecular weight comprised between from 500 to 1,300.