FR2890971A1 - Polyvinylidenefluoride-based composition, useful as adhesive layer between fluorinated coating and metal surface, comprises polyvinylidenefluoride, vinylidenefluoride copolymer and (meth)acrylic, vinylic or allylic copolymer - Google Patents

Abstract

Polyvinylidenefluoride (PVDF) based composition having adhesion properties on various metals comprises PVDF at 0-99 wt.%; vinylidenefluoride copolymer (I) 0-99 wt.%; and (meth)acrylic, vinylic or allylic copolymer (II) 0.5-50 wt.% having phosphorus chemical groups reactive with metal. An independent claim is included for a process of allowing a fluorinated polymer adhesion on the metal comprising using the composition, where the composition is used as an adhesive layer between the fluorinated coating and the metal surface.

Description

DESCRIPTION OF THE INVENTION

  TECHNICAL FIELD OF THE INVENTION [1] The present invention relates to novel additives bearing phosphonic acid or diacid phosphate groups and to their use as adhesion promoter for fluorinated resins on a metal surface. This invention can be applied to fluorinated polymeric metal surface coatings (tubes, profiles, battery electrodes, etc.) for which chemical resistance and corrosion resistance is required.

  STATE OF THE ART [2] Fluorinated polymers and in particular polyvinylidene fluoride (PVDF) exhibit exceptional chemical resistance (mainly to acids) and excellent resistance to UV They are used mainly for the protective coatings of various substrates and in particular metal substrates. For all these reasons, fluoropolymers are used in many applications and more particularly as a coating in fields of high technology (industrial paints, electrical components, electronics, oil-filled metal tubes, batteries, etc.).

  [3] However, fluoropolymers have the disadvantage of having low adhesion properties on their supports (polymers, metals, cement, etc.). Thus, it remains difficult to confer on these supports the exceptional properties of fluoropolymers.

  [4] In order to improve these adhesion properties, it has been tried to insert polar groups by means of copolymerization of VDF with a monomer carrying a polar group or by grafting irradiation of polar monomers on PVDF. JP-B1-2-604 and JP A1-6-172452 propose introducing carboxylic acid groups by copolymerizing VDF with carboxylic acid-bearing monomers. However, this method is particularly difficult to implement for several reasons. Firstly, it is very difficult to synthesize carboxylic acid-bearing monomers which polymerize regularly with VDF. Moreover, the fluoropolymers obtained have relatively low molar masses, which tends to generate the loss of the main properties of PVDF. JP-A1-50-41 791 proposes a grafting pathway for PVDF by irradiation of carboxylic acid-bearing monomer. However, this route, which is very difficult to set up industrially, also leads to chain breaks and to crosslinking phenomena.

  [5] Polymethyl methacrylate (PMMA) resins are known to be well compatible with PVDF (US5242976). However, since the glass transition temperature of the PMMA is too high, the mixture of PMMA and PVDF exhibits a loss of elasticity and therefore does not have any adhesion to metal. Furthermore, other mixing tests with acrylic polymers (US5242976) elastomer type and therefore having lower glass transition temperatures, have been made. However no adhesion result on metal surface is obtained through this system. In view of the compatibility of PMMA with PVDF, WO9727260 proposes the use of methacrylic copolymers bearing functional groups (carboxylic acid, mercaptans, oxazoline, etc.) as adhesives for PVDF resin on metal. However, of these reactive groups, none is strongly bound to the metal and the adhesion properties to the metal are poor.

  [6] The patent W00049103 also proposes to use methacrylic copolymers bearing functional groups (carboxylic acid, mercaptans, oxazoline, etc.), however it is necessary to add polysulfide adhesion promoters to obtain good properties of accession.

  [7] US2003 / 0170538 proposes a totally different alternative by a two-step synthesis method. The first step is to generate double bonds on PVDF by dehydrofluorination reactions using basic compounds. The second step consists of oxidizing these double bonds in an aqueous medium, preferably with hydrogen peroxide. However, this method is particularly aggressive with respect to PVDF and tends to lead to decreases in molar mass and loss of properties. Moreover this method is difficult to envisage within the framework of an industrial development.

  OBJECT OF THE INVENTION [008] The object of this invention lies in the preparation of additives bearing phosphonic acid or diacid phosphate groups and then in the use of these additives mixed with fluoropolymers to give them adhesion to a metal surface while retaining their thermal, mechanical and solvent resistance properties.

  [009] The inventors have found that a fluorinated composition comprising at least two of the following three components - (a) a PVDF resin (A), (b) a VDF copolymer resin (B) (c) a copolymer of the type vinylic or (meth) acrylic or allylic, one of the comonomers bearing phosphonic acid or diacid phosphate groups having high adhesion properties on metal surface (C), has good adhesion properties on metal materials in particular , and they have discovered that such characteristics give these metal coatings better resistance properties to solvent resistance, chemical and thermal.

  The use of a mixture of 1 to 99% by weight of (A) and from 1 to 99% by weight of (B) makes it possible to obtain fluorinated resins having modulable elasticity properties. Thus, the higher the proportion of (B), the more elastic the resin will be. However, the higher the proportion of (B) is and the less the mixture will be permeable to solvents. It is therefore necessary to choose a suitable percentage that meets the required properties of the coating in terms of elasticity and permeability to solvents.

  [011] The PVDF polymer or copolymer used in the present invention can be obtained by suspension polymerization (US Pat. No. 3,553,185, EP0120524) or by emulsion polymerization (US4025709, US4569978, US4626396, EP0655468) of vinylidene fluoride and preferably has a value of MFR melt flow rate under 2.16 kg between 0.005 and 300 g / 10 minutes and preferably between 0.01 g and 30 g / 10 minutes.

  [012] The VDF copolymer resin (B) is based on the copolymerization of VDF with a comonomer which copolymerizes in an acceptable manner with VDF. The proportion of VDF in the copolymer is between 10 and 99% by weight and preferably between 50 and 99%. The comonomer may also be of the fluorinated type, for example, tetrafluoroethylene, hexafluoropropene, trifluoroethylene, trifluorochloroethylene, vinyl fluoride and perfluoroalkyl vinyl ether. The comonomer may be unsaturated olefin, for example ethylene, propylene or a hydrocarbon-based vinyl ether compound or a hydrocarbon-based allyl ether compound. One or more of these comonomers can be used. These copolymers can be obtained by suspension polymerization (US3553185, EP0120524) or by emulsion polymerization (US4025709, US4569978, US4626396, EP0655468) of vinylidene fluoride and preferably has a MFR melt flow rate value of 2.16 kg between 0.005 and 300. g / 10 minutes and preferably between 0.01 g and 30 g / 10 minutes.

  [13] The copolymers bearing phosphonic acid or diacid phosphate groups (C) are composed of several monomers. These copolymers can be synthesized by a solution or emulsion or suspension polymerization process. They can be in the form of random copolymers, gradient copolymers, block copolymers, graft copolymers. They can be obtained by radical polymerization, controlled radical polymerization, ionic polymerization, group transfer polymerization, coordination polymerization from one or more of the monomers selected from the following; vinylidene fluoride, propylene hexafluoride, tetrafluoroethylene, chlorotrifluoroethylene, perfluoroalkyl methacrylate, alkyl methacrylate, alkyl acrylate, vinyl acetate and the monomer (s) carrying phosphonic acid group or diacid phosphate.

  [14] In this series, the alkyl (meth) acrylate compound (s) may be selected from the following list composed of methyl (meth) acrylate, (meth) ) ethyl acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate.

  [15] The monomer carrying phosphonic acid group or diacid phosphate which has a high affinity with the metal may be chosen from the following non-exhaustive list: 2-Propenoic acid, 2-methyl-, phosphonomethyl ester [87243-97-8] ; 2-Propenoic acid, 2-methyl-, (phosphonooxy) methyl ester [73310-45-9]; 2-Propenoic acid, 2-methyl-, 2-phosphonoethyl ester [80730-17-2]; 2-propenoic acid, 2-methyl-, 2 (phosphonooxy) ethyl ester [24599-21-1]; 2-propenoic acid, 2-methyl-, 3-phosphonopropyl ester [252210-30-3]; 2-Propenoic acid, 2-methyl-, 3 (phosphonooxy) propyl ester [82427-01-8]; 2-Propenoic acid, 2-methyl-, 4-phosphonobutyl ester [477874-42-3]; 2-propenoic acid, 2-methyl-, 4 (phosphonooxy) butyl ester [40074-59-7]; the polymerizable aminoalkylenephosphonic compounds described in claim 1 of the patent FR0403272; Polyethylene glycol methacrylate bearing a diacid phosphate group such as, for example, SIPOMER PAM 100 (RHODIA) [658695-59-1]; Polypropylene glycol methacrylate bearing a diacid phosphate group such as, for example, SIPOMER PAM 200 (RHODIA) [658695-60-4]; Phosphonic vinyl acid [1746-03-8] [016] The copolymers bearing phosphonic acid or diacid phosphate groups (C) are composed of: - from 50 to 99% by weight of one or more monomers which have a compatibility with PVDF for example, vinylidene fluoride, propylene hexafluoride, tetrafluoroethylene, chlorotrifluoroethylene, alkyl (meth) acrylates, vinyl esters - from 1 to 50% by weight of one or more monomers described in [15]. ] and which have a high affinity with the metal [17] Thus, the adherent fluorinated metal substrate formulations have the following proportions of (A), (B) and (C): from 0 to 99% by weight of PVDF ( A) from 0 to 99% by weight of copolymer of VDF (B) of 0.5 to 50% by weight of copolymer bearing phosphonic acid or diacid phosphate (C) groups [18] The adherent fluorinated formulations on a metal substrate can be prepared by a process in phase or by an aqueous phase process (emulsion or suspension) or by mechanical mixing in the molten state.

  In the case of the solvent phase process, the components (A), (B) and (C) are dissolved in a solvent chosen from N-methylpyrrolidone, N, N-dimethylformamide, tetrahydrofuran, dimethylacetamide and di-methylsulfoxide. Hexamethylphosphoramide, tetramethylurea, acetone, methyl ethyl ketone at a temperature below the boiling point of the solvent.

  In the case of the aqueous phase process (emulsion or suspension), the three components (A), (B) and (C) are in an aqueous form (emulsion or Phosphonic acid, [(4-ethenylphenyl) methyl] -; [53459-43-1] Phosphonic acid, [(4-ethenylphenyl) methyl] -, monomethyl ester [71303-24-7] suspension and the composition is prepared by mixing these aqueous phases (emulsion or suspension).

  In the case of the melt mechanical mixing process, the components (A), (B) and (C) can be melt blended by conventional methods (rheometer, mono-extruder and twin-screw extruder) at temperatures between 100 and 300 C and preferably between 140 and 200 C.

  [19] The metal substrates on which the fluorinated formulations of the present invention can adhere are selected from the following list: iron, stainless steel, galvanized steel, aluminum, titanium, lead, silver, nickel, chromium, copper, manganese, vanadium, lithium, cobalt and various alloys of such metals.

  [20] As explained above, by means of the present invention, it becomes possible to greatly improve the adhesion of fluorinated resins to metal substrates. The metal substrates can be of different shapes (film, sheet, panel, tube, rod, shim, monofilament, etc.) and can be coated with the fluorinated resins according to different methods (calendering, extrusion, lamination, multilayer injection, coating by bed fluidized, soaking, spraying and hot pressing).

[21] Examples

  The examples below are given for illustrative purposes only and therefore have no limiting character of the present invention.

[22] Example 1

  In a 500 ml two-neck flask equipped with a condenser and an inlet of argon, 25 g (0.1202 mol) of 2-Propenoic acid, 2-methyl- (dimethoxyphosphinyl) methyl ester are introduced [86242-61 -7], 108 g of methyl methacrylate (1.08 mol) in 250 ml of acetonitrile. The solution is swept by a stream of argon for 15 minutes and is heated to 70 ° C. Then 2 g of azobisobutyronitrile (AIBN) (0.012 mol) are introduced.

  After 16 hours of reaction, the acetonitrile is evaporated off under reduced pressure and the copolymer is solubilized in 200 ml of tetrahydrofuran. This solution is then precipitated in 10 liters of pentane.

  After filtration and drying, a white powder is obtained composed of copolymer 40 bearing a phosphonic ester group with a yield of 90%.

[023] Example 2:

  In a 500 ml two-neck flask equipped with a condenser and an inlet of argon, 100 g of phosphonated methacrylic copolymer according to Example 1 are introduced and dissolved in 200 ml of chloroform. 45 g of trimethylbromosilane are added dropwise and the reaction is allowed to proceed for 10 hours. Finally, 100 g of methanol are added and then the solvents are evaporated and the copolymer is solubilized in 200 ml of tetrahydrofuran. This solution is then precipitated in 10 liters of pentane.

  After filtration and drying, a white powder is obtained consisting of a phosphonic acid group-bearing copolymer with a yield of 90%.

[024] Example 3:

  90 parts by weight of PVDF SOLEF 1010/1001 homopolymer resin (SOLVAY) are introduced into a HAAKE POLYLAB rheometer at a temperature of between 170 ° C. and 240 ° C. for 5 minutes. 10 parts by weight of methacrylic copolymer bearing phosphonic acid groups according to Example 2 are added to this molten resin.

  After this mixing step, a fluorinated composition is obtained which can be put into the form of granules by means of a twin-screw extruder at temperatures between 170 and 240 ° C. Finally, a multilayer coating composed of the following layers is produced. (a) Steel sheet (1 mm thickness) (b) PVDF and phosphonic additive film according to the present example acting as adhesive between the metal and the PVDF (200 m thickness) ( c) PVDF SOLEF 1010/1001 (500 m thickness) This multilayer structure was pressed for 10 minutes at 180 ° C. at a maximum pressure of 10 kg / cm 2 and showed adhesion properties of the order of 3 kg / cm 2. cm.

[025] Example 4:

  90 parts by weight of PVDF SOLEF 1010/1001 homopolymer resin (SOLVAY) are introduced into 1000 parts of N-methyl pyrrolidinone. 10 parts by weight of methacrylic copolymer carrying phosphonic acid groups according to Example 2 are added to this solution.

  This solution of PVDF phosphonic resin, referred to as PVDF A, is deposited on a Q-panel steel plate. A film having a thickness of 5 to 10 m is obtained by thermal evaporation of the solvent.

  [026] Against Example 4: 1. 100 parts by weight of PVDF SOLEF 1010/1001 homopolymer resin (SOLVAY) are introduced into 1000 parts of N-methyl pyrrolidinone.

  This PVDF solution PVDF B is deposited on a Q-panel steel plate. A film having a thickness of 5 to 10 m is obtained by thermal evaporation of the solvent.

  2. 90 parts by weight of PVDF homopolymer resin SOLEF 1010/1001 (SOLVAY) are introduced into 1000 parts of N-methyl pyrrolidinone. 10 parts by weight of methacrylic copolymer bearing carboxylic acid groups obtained by copolymerization of methyl methacrylate with methacrylic acid (90/10 molar) are added to this solution.

  This solution of PVDF carboxylic acid, referenced PVDF C, is deposited on a Q-panel steel plate. A film having a thickness of 5 to 10 gm is obtained by thermal evaporation of the solvent.

  [027] Comparison of the 3 PVDF A, PVDF B and PVDF C coatings The following two tables present successively: - CROSS CUT TEST ISO 2409 - stability tests of immersed coatings in water Grid test ( Cross-cut Test) ISO 2409 PVDF B 100% pull-out PVDF C 40% pull-out PVDF A 0% pull-out Stability testing of coatings immersed in water t = 0 t = 1 min t = 5 min t = 10 min t = 30 min t = 60 min t = 120 min PVDF Low peel adhesion important PVDF C Good Good low weak peel adhesion adhesion adhesion peel moderate moderately important PVDF A Good no step no step no step no adhesion detachment detachment detachment detachment detachment detachment

Claims (11)

  Compositions based on polyvinylidene fluoride having adhesion properties on various metals, characterized in that it consists of at least: from 0 to 99% by weight of PVDF (A), from 0 to 99% by weight of copolymer of VDF (B) - from 0.5 to 50% by weight of copolymer of (meth) acrylic or vinylic or allylic type bearing phosphorus-containing chemical groups reactive with the metal (C) 2 Compositions based on polyvinylidene fluoride having properties adhesive composition on various metals according to claim 1, wherein the groups reactive with the metal of the copolymer (C) are phosphate or phosphonate groups bearing at least one acid group (P-OH group).   3 Compositions based on polyvinylidene fluoride having adhesion properties on various metals according to claims 1 and 2, wherein the copolymer (C) of the (meth) acrylic or vinyl or allylic type carrying phosphorus chemical groups reactive with the metal is a copolymer composed of 50 to 99.5% by weight of one or more monomers which has good compatibility with PVDF and 0.5 to 50% by weight of one or more monomers carrying metal-reactive phosphorus chemical groups.   4 compositions based on polyvinylidene fluoride having adhesion properties on various metals according to claims 1, 2 and 3 in which the comonomer (s) of the additive C which provide compatibility with A are chosen from vinylidene fluoride, propylene hexafluoride, tetrafluoroethylene, perfluoroalkyl (meth) acrylate, alkyl (meth) acrylates, vinyl esters.   Compositions based on polyvinylidene fluoride having adhesion properties on various metals according to claims 1, 2 and 3 in which the comonomer (s) carrying phosphorus chemical groups reactive with the metal is (are) chosen from Propenoic acid, 2-methyl-, phosphonomethyl ester; 2-Propenoic acid, 2-methyl-, (phosphonooxy) methyl ester; 2-Propenoic acid, 2-methyl-, 2-phosphonoethyl ester; 2-propenoic acid, 2-methyl-, 2- (phosphonooxy) ethyl ester; 2-Propenoic acid, 2-methyl-, 3-phosphonopropyl ester; 2-propenoic acid, 2-methyl-, 3- (phosphonooxy) propyl ester; 2-propenoic acid, 2-methyl-, 4-phosphonobutyl ester; 2-propenoic acid, 2-methyl-, 4 (phosphonooxy) butyl ester; Phosphonic acid, [(4-ethenylphenyl) methyl] -; Phosphonic acid, [(4-ethenylphenyl) methyl] -, monomethyl ester polymerizable aminoalkylene phosphonic compounds; Polyethylene glycol methacrylate bearing a diacid phosphate group such as, for example, SIPOMER PAM 100 (Rhodia); Polypropylene glycol methacrylate bearing a diacid phosphate group such as, for example, SIPOMER PAM 200 (RHODIA) Vinyl phosphonic acid.   Compositions based on polyvinylidene fluoride having adhesion properties on various metals according to claims 1, 2 and 3 in which the copolymer (C) (meth) acrylic or vinyl or allyl bearing phosphorus chemical groups reactive with the metal is synthesized by a polymerization process in solution or emulsion or microemulsion or miniemulsion or suspension.   7 Compositions based on polyvinylidene fluoride having adhesion properties on various metals according to claims 1, 2 and 3 in which the copolymer (C) (meth) acrylic or vinyl or allyl carrying phosphorus chemical groups reactive with the metal is in the form of random copolymer, gradient copolymer, block copolymer or graft copolymer.   Compositions based on polyvinylidene fluoride having adhesion properties on various metals according to claims 1, 2 and 3 in which the copolymer (C) (meth) acrylic or vinyl or allyl carrying phosphorus chemical groups reactive with the metal can be synthesized by various polymerization techniques such as radical polymerization, controlled radical polymerization, ionic polymerization, group transfer polymerization, coordination polymerization.   Compositions based on polyvinylidene fluoride having adhesion properties on various metals according to claim 1, in which the copolymer of VDF (B) is obtained by copolymerization of VDF with one or more fluorinated monomer (s). selected from tetrafluoroethylene, hexafluoropropene, trifluoroethylene, trifluorochlorethylene, vinyl fluoride and perfluoroalkylvinyl ether or with a non-fluorinated monomer (s) chosen from ethylene, propylene, the vinyl ether-type hydrocarbon compounds and the allyl hydrocarbon ether.   Process for the adhesion of fluoropolymer to the metal, characterized in that the fluorinated composition according to claim 1 is used as an adhesive layer between the fluorinated coating and the metal surface.   Process for the adhesion of fluoropolymer to the metal, characterized in that the fluorinated composition according to claim 1 is used in admixture with the fluorinated coating and then deposited on the metal surface.   Process for the adhesion of fluoropolymer to the metal, characterized in that the fluorinated composition according to claims 10 and 11 is applied in the melt, emulsion (or aqueous phase) or solvent phase.   Process for the adhesion of fluoropolymer to the metal, characterized in that the fluorinated composition according to Claims 10 and 11 is applied by calendering, extrusion, lamination, multilayer injection, fluidized bed coating, dipping, spraying and hot pressing. .   Process for the adhesion of fluoropolymer to the metal, characterized in that the fluorinated composition according to claims 9 and 10 is applied to a metal surface of film or sheet or panel or tube or rod or bank or monofilament type.   Process for the adhesion of fluoropolymer to the metal, characterized in that the fluorinated composition according to claims 9 and 10 is applied to the following metal substrates: iron, stainless steel, galvanized steel, aluminum, titanium, lead, silver, nickel , chromium, copper, manganese, vanadium, lithium, cobalt and various alloys of such metals.