FR2797278A1 - PLUG IMPLEMENTING A COMPOSITION OR PREMIX BASED ON VOLATILE CORROSION INHIBITORS - Google Patents

Abstract

The subject of the invention is a stopper based on polymers, characterized in that it uses a composition or premix based on volatile corrosion inhibitors which comprises an effective amount of at least one structuring agent consisting of a substance. solid or pasty, the melting point of which is 40 to 110 ° C., preferably 50 to 90 ° C. It also relates to the use of the aforesaid plug for the internal protection of hollow metal parts against corrosion.

Description

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  PLUG IMPLEMENTING EU COMPOSITION OR PREMIX

  i BASE OF VOLATILE CORROSION INHIBITORS The subject of the invention is plugs based on polymers and one of the components of which is a composition or premix based on volatile corrosion inhibitors. It also relates to the use of the aforesaid plugs for the internal protection of metal parts

hollow against corrosion.

  In the present invention, the term "plugs" means any part capable of obstructing the opening of a hollow part, such as plugs, capsules, threaded bodies, used for the localized volatile corrosion protection of certain internal, hollow parts. metallic parts. The constituent material of the plugs which is based on polymers and one of the components of which is a composition or premix based on volatile corrosion inhibitors, has been used to prepare

packaging items.

  It is in fact known to use volatile corrosion inhibitors when it is a question of protecting against corrosion of metal parts sensitive to corrosion, in particular those which are made of mild steel with low carbon content and which, once machined , are shipped as is to their place of destination by sea container for on-site finishing, in particular by painting; the risk of corrosion is then considerable, especially when the parts in question are sent to the

hot and humid areas.

  For example, when the metal parts to be protected are wrapped in films, the LCIs are incorporated into the material constituting these films; since these films can be in direct contact with the surface of the parts to be protected, corrosion inhibitors acting on contact are also

  incorporated into the constituent mass of these films.

  Volatile corrosion inhibitors offer, under these conditions, very good protection against corrosion and have the advantage of making it possible to avoid having to resort to conventional techniques for protecting metal parts; these conventional techniques consist of the application of paints, varnishes, plastics, waxes, greases and oils which should be removed before finishing on site, which results in

  additional costs and pollution.

  Volatile corrosion inhibitors, generally designated by ICV, use additives whose vapor pressure can be considered to be significant at the temperature of use (for example, of the order of -5 to 10-1 mm Hg, at 20 C), and which are capable of inhibiting

corrosion of metals.

  These LCIs act thanks to the fact that they are transported in the form of vapor to the metal surface to be protected, to be adsorbed there or else dissolved in a

possible condensation water.

  Products are also known which are classified by extension in the LCIs due to the fact that one of their reaction products has an adequate vapor pressure. Thus, for example, sodium nitrite, in the presence of ammonium ions, can form ammonium nitrite which is relatively volatile. Nitrite

  starting sodium is then considered as an LCI.

  It is sometimes necessary to protect against corrosion only internal parts of hollow metal parts of large dimensions and complex geometry,

  in particular cavities, threaded parts or tubular holes.

  Plugs according to this invention, based on polymers and possibly other structuring agents, shaped by the usual techniques of the polymer industry (extrusion, injection, thermoforming) make it possible to obstruct the openings of metal parts and their provide the necessary localized protection, considerably minimizing costs. To incorporate ICV into the constituent material of packaging, in particular films which are often based on thermoplastic polymers, it is known to make direct mixtures of ICV powders with the polymers and to form directly by extrusion or injection the

items in question.

  At the extrusion temperature which is approximately 160 ° C. for low density polyethylene and 240 ° C. for polypropylene, the LCIs have an extremely high volatility which leads, in the case of thin articles, to the appearance high porosity and a high risk of degradation and / or decomposition with elimination of at least part of the LCI. The anticorrosion effectiveness of such articles is therefore greatly reduced as a result of the loss of active ingredients. To remedy this drawback, that is to say to limit the loss of ICV during the actual preparation of the articles, it has been proposed to use premixes containing the ICVs, that is to say active ingredient concentrates dispersed in carriers such as polymers, solvents and plasticizers; premixes based on polymers (Patent BR-A-9001035) have the general advantage of being homogeneous and easy to handle; these premixes are then incorporated into the

  polymers for the preparation of articles.

  Given, however, that the temperatures used at the time of preparation of the premixes are often greater than 150 ° C., there is at least partial degradation of said premixtures; thus and by way of example, it is reported that the dicyclohexylamine nitrite, mixed and extruded with polyethylene at 160 ° C., leads to premix granules which have a coloration

  dark yellow, characteristic of strong degradation,

  that is, loss of activity. To avoid these excessive degradations with heat, it has been proposed to use liquid premixes, based on oil, which do not require passing to high temperatures during their manufacture (patent

US-A-4,913,874).

  However, since the LCIs are infrequently soluble in these oily media, there follows a heterogeneity of the premixes obtained and the appearance of

  difficulties due to over-concentration or under-

  local concentrations during their subsequent incorporation into the polymers from which the articles are made. It has also been proposed to remedy this drawback by using liquid premixes in the form of solvent or oily solutions comprising ICVs, premixes which are not incorporated during extrusion, but applied to films by spraying, thus forming, after evaporation of the solvent, either a powdery layer of ICV (patent DE 3,417,149 Ai), or a

  oily layer containing ICVs (GB patent 2,188,274 A).

  The disadvantage of these premixes lies in the fact that the LCIs are not trapped in a matrix requiring slow release, the protection obtained therefore being of short duration. Furthermore, the adhesion of the layers deposited on the articles is weak and leads to losses during handling and to the obligation to clean the parts to be protected, which is precisely to be avoided. The object of the invention is to provide plugs based on polymers using at least one composition based on ICV which responds better than those which already exist.

  to the various desiderata of the practice.

  The invention also aims to propose new uses for these stoppers based on ICV, such as partial and localized protection of certain

  internal parts of hollow metal parts.

  And the Applicant Company had the merit of finding, after in-depth research, that these aims were achieved when recourse is had to caps based on polymers employing a composition based on inhibitors of volatile corrosion which comprises structuring agents capable of allowing the preparation of a premix at temperatures low enough to limit as much as possible the release and / or degradation of

ICV during this preparation.

  Consequently, the stoppers according to the invention, based on polymers are characterized by the fact that they use a composition based on volatile corrosion inhibitors which comprises an effective amount of at least one structuring agent, consisting by a solid or pasty substance whose melting point is 40 to 110 C, preferably 50 to 90 C, which allows the release and / or degradation of LCI at the time of formation of the composition or premix is limited to

maximum.

  According to an advantageous embodiment, the composition used in the stoppers according to the invention comprises from 1 to 90%, preferably from 20 to 60% by weight of at least one volatile corrosion inhibitor and from 10 to 99 %, preferably from 40 to 80% of at least one structuring agent consisting of a solid or pasty substance whose melting point is from 40 to 110 C, preferably from

at 90 C.

  According to another advantageous embodiment, the composition used in the stoppers according to the invention comprises at least one structuring agent chosen from the group of those comprising aliphatic and / or resinous compounds, solid or pasty, with a low point of fusion

  between 40 and 110 C, preferably between 50 and 90 C.

  According to another advantageous embodiment of the composition used in the stoppers in accordance with the invention, the structuring agent is chosen from the group comprising the aliphatic organic compounds mono- or polyfunctional, linear and / or little branched with chains hydrocarbons having at least 10 carbon atoms, including in particular: - mono- or dicarboxylic acids, optionally oxidized, saturated or unsaturated, their esters and their salts, - phosphoric, sulfonic and phosphonic acids, their esters with alcohols and their salts of alkali, alkaline earth metals, of zinc, of aluminum and / or of organic amines, - the cyclic or acyclic compounds of the group comprising lactones, ketones, aldehydes, amides and acetals, - higher alcohols , primary or secondary, cyclic or acyclic, optionally polyalkoxylated, with hydrocarbon chain having at least 10 carbon atoms, - alipha hydrocarbons linear and / or slightly branched ticks, in particular paraffins and isoparaffins, - polyolefins and their copolymers with low

  molecular weights from 3000 to 20,000 g / mole.

  - polyglycols, in particular polyethylene glycols

  molecular weight from 2000 to 10,000 g / mole.

  According to another advantageous embodiment of the composition used in the stoppers according to the invention, the structuring agent is chosen from the group comprising resinous compounds having a polymeric and / or cyclic structure and which may contain, in a minority proportion , aromatic derivatives and

cyclic terpenes.

  According to another advantageous embodiment of the composition according to the invention, the structuring agent is chosen from the group of those identified in Table A below and some of which are original waxes or oils

natural or synthetic.

TABLE A

  Origin Chemical nature Name Density to Index of majority agent of fusion agent 25 C ASTM penetration to structuring structuring agent (C) D 1298 25 "C ASTM D 1321 Ester (Camauba cirotate 83-86 0995 myricyle) _836, Natural Ester (palmitate Myricyte wax) of bees 62-65 0.955 Paraffinic hydrocarbons Paraffin 50-60 0.900 15 (mixture) Hydrocarbons C Mineral isoparaffinic remco 69 0.930 29 and naphthenic crystalline Aliphatic hydrocarbons10-70 / 20 C 43-45 (blend) Polyethylene Polyethylene wax88 0.930 6.5 polyethylene

Hydrocarbons Micro wax

  isoparaffinic crystalline 85 - 13 oxidized oxidized Synthetic Phosphoric ester

fatty alcohols - 83 - 89 0.998 -

  C1i / C18 Polyethylene glycol Polyethylene - 5759.11 2991 C glycol 4000 According to another advantageous embodiment, the composition used in the stoppers according to the invention comprises at least one volatile corrosion inhibitor chosen from the group comprising: - nitrogen derivatives and in particular, on the one hand, the aliphatic, aromatic, acyclic or cyclic amines including dicyclohexylamine, cyclohexylamine, morpholine, diisopropylamine and benzylamine, their organic salts including benzoates, carbamates, laurates, caprylates, succinates or minerals including nitrites, nitrates, carbonates, phosphates, phosphites and, on the other hand, heterocycles including imidazole and its derivatives,

  triazoles and their derivatives, as well as hexamethylene-

  tetramine, - the nitrogen-oxide derivatives including the alkali or alkaline-earth metal salts of nitrous acid and - the benzo derivatives of these metals such as

sodium benzoate.

  It is possible to include in the composition used in the stoppers according to the invention and / or in the stoppers one or more adjuvants chosen from the group comprising: - antioxidants and / or inhibitors of degradation including bis-phenol A, butyl-hydroxytoluene, di-tert-butyl-phosphite, trinonyl-phenoxy-phosphite, dilauryl-thio-dipropionate,

  - anti-UV absorbers including benzo-

  triazoles, triazines, hydroxybenzophenones and free radical inhibitors including AES or Hindered Amine Light Stabilizer in English, - external antistatic agents including phosphoric ethers of ethoxylated alcohols and ethoxylated amine chlorides, or internal, including ethoxylated fatty amines, ethoxylated polyols and alkylsulfonates, - external or internal lubricating agents including paraffins, fatty alcohols, fatty acids, esters of fatty acids and alcohols and amides, - plasticizers including dioctylphthalate, tricresylphosphate and diipers of aliphatic acids, - mineral pigments including PbSO4, PbCrO4, CdS. ZnS, organic pigments including azo derivatives, phthalocyanines or antraquinones and - flame retardants including brominated compounds and chlorinated phosphorus, hydrides of Al, Mg and Zn compounds, as well as epoxy oligomers, - mi charges mineral including chalk and

  carbonates, talcs, clays, silicas.

  These adjuvants can also be added only at the time of incorporation of the composition into the polymer from which plugs are produced in accordance with the invention or into the structuring agent from

  from which the plugs according to the invention are produced.

  These plugs are characterized in that at least one of their components consists of a composition described above and that they are prepared from at least one polymer which is at least 50% in

weight in their constitution.

  The aforementioned polymers which form at least 50% by mass in the constitution of the stoppers in accordance with the invention can be chosen from those of the group comprising: - polyolefins including polyethylenes, polypropylene, polybutene and their copolymers with one or more unsaturated monomers including vinyl acetate, acrylic acid and its esters with short carbon chain alcohols, - polyvinyl chloride and its copolymers, acrylic copolymers and their derivatives, and

  - polyamides, polystyrenes, polycarbo-

  nates, polyesters, polyurethanes, rubbers including natural rubber, styrene-butadiene and

polychloroprene.

  The process for preparing these plugs generally comprises successively a step of preparing a composition or premix based on volatile corrosion inhibitors according to the invention and a subsequent step during which the premix is incorporated into a of the above polymers, the plugs being obtained in particular by extrusion, molding, injection molding or thermoforming

  from the mixture comprising the premix and the polymer.

  The caps are used for the protection of the internal parts of hollow metallic parts susceptible to corrosion, during their transport or their storage, without a protective treatment being applied.

complementary to these pieces.

  The invention can be understood even better with the aid of the nonlimiting examples which follow and which

  relate to advantageous embodiments.

  For the preparation of an LCI, 70 g of sodium nitrite, 17.5 g of benzotriazole and 12.5 g of ammonium benzoate are mixed and then micronized in an air jet micronizer to give 100 g of homogeneous powdery mixture designated by [la] and having an average particle size included

  between 1 and 15 pm; this powder constitutes an ICV.

  In a heating tank provided with a rotating and scraping stirrer, 226 g of the paraffin defined in table A are melted at 65 ° C., then 100 g of powder [la] are

  incorporated into the melt and carefully dispersed.

  Then added 2 g of anti-UV agent (sold under the brand TINUVIN 622 LD by Ciba Geigy), 2 g of antioxidant - degradation inhibitor (sold under the brand CHIMASSORB 944 LD by Ciba Geigy) and 3 g of

  Color Index PY10401 / 70 yellow dye.

  The dispersion is carried out with stirring at a speed between 300 to 500 revolutions / minute, for 1!

minutes.

  The 333 g of the mixture thus obtained, which constitutes a premix [lb], are poured for cooling on a laboratory scaly machine maintained at 10 ° C., then cut into scales with a size between 0.5 and 10 mm. 300 g of premix [lb] are mixed cold and homogeneously with 5.7 kg of low density polyethylene (d = 0.925 g / cm3 and melt flow index IF = 20 g / 10 minutes); the mixture obtained is injected at a temperature varying between 145 and 160 C in a nest mold cooled to C, mounted on a KRAUSS MAFFEI C-40 t injection machine, with hydraulic closure (400 kN) and which works at a rate of 30 strokes / minute; the residence time of the molten material in each of the six zones of the cylinder is

15.6 seconds.

  As a finished article, ICV capsules of yellow color, designated [ic], 20 mm in diameter, 1 to 3 mm thick and 1 g in mass, are used which are used to protect the cavities and threaded parts of the motors.

automobiles.

  The volatile anticorrosion efficiency of these ICV [lc] capsules was tested on mild steel test pieces, in the form of studs; the test used uses two capsules and corresponds to the North American standard FEDSTD

101, method 4031B.

  This test method consists in placing a steel pad in a confined atmosphere charged with ICV released from the film, then in causing controlled cooling on the pad surface in order to

  cause possible oxidation after a determined time.

  The degree of rusting indicates the anti-corrosion efficiency

  of the plug with respect to the material constituting the stud.

  At the end of this test, it can be seen that the steel stud protected by the corrosion-inhibiting vapors which have been released from the two ICV capsules [lc] does not have

of oxidation on its surface.

  The same test was carried out, for comparison, using "control" capsules, designated by [ld], which are identical in all respects to the capsules [lc], except that they do not contain the LCI identified above [lb]; the 100 g of powder [la] which are part of the premix composition [lb] have been replaced by 100 g

  mineral filler based on calcium carbonate.

  At the end of the test, the pad protected by the control capsules [ld] is completely attacked: we observe

  numerous pits and rust on 100% of its surface.

EXAMPLE 2

  For the preparation of an LCI, 300 g of premix [lb] defined in Example 1, are mixed cold and in a homogeneous manner with 5.7 kg of low density polyethylene (d = 0.925 g / cm3 and IF index = 20 g / minute); the mixture obtained is injected at a temperature varying from 135 to 150 C in a nest mold cooled to 400C,

  mounted on a KRAUSS MAFFEI C series injection machine -

  t, with hydraulic closure (400 kN) and which works at a rate of 60 strokes / minute; the residence time of the molten material in each of the six zones of the cylinder is

9.9 seconds.

  As a finished article, yellow ICV stoppers, designated [2c], 55 mm in diameter, 1.5 mm thick and 6.5 g in mass, used to protect the cavities and threaded parts, are obtained. automotive engines. The volatile anti-corrosion efficiency of these ICV [2c] closures was tested on mild steel specimens, in the form of studs; the test used involves a third of the stopper, i.e. 2.2 g and corresponds to the North American standard

  FED-STD 101, method 4031B, described in Example 1.

  At the end of this test, it can be seen that the steel stud protected by the corrosion-inhibiting vapors which have emerged from the ICV plug [2c] does not have

of oxidation on its surface.

  The same test was carried out, for comparison, using a "control" stopper, designated by [2d], which is identical in all points to the stopper [2c], except for the fact that it does not contain the LCI identified above [lb]; the g of powder [la] which are part of the premix composition [lb] have been replaced by 100 g of filler

  mineral based on calcium carbonate.

  At the end of the test, the pad protected by the control plug [2d] is completely attacked: we observe

  numerous pits and rust on 100% of its surface.

  Rg llmDICàATIONS 1. Polymer-based stopper, characterized in that it uses a composition or premix based on volatile corrosion inhibitors which comprises an effective amount of at least one structuring agent consisting of a solid or pasty substance whose melting point

  is 40 to 110 C, preferably 50 to 90 C.

  2. Cap according to claim 1, characterized in that it uses a composition or premix comprising from 1 to 90%, preferably from 20 to 60% by weight of at least one volatile corrosion inhibitor and from 99%, preferably from 40 to 80% of at least one structuring agent consisting of a solid or pasty substance whose melting point is from 40 to 110 C, preferably from

at 90 C.

  3. Cap according to one of claims 1 and 2,

  characterized by the fact that it uses a composition or premix, the structuring or pasty agent of which is chosen from the group comprising aliphatic and / or resinous compounds, solid or pasty, with a low melting point included

  between 40 and 110 C, preferably between 50 and 90 C.

  4. Cap according to one of claims 1 to 3,

  characterized by the fact that it uses a composition or premix whose solid or pasty structuring agent is chosen from the group of those comprising aliphatic, mono- or polyfunctional, linear and / or sparingly branched with hydrocarbon chains having at least 10

carbon atoms.

  5. Stopper according to claim 4, characterized in that it uses a composition or premix whose structuring agent is chosen from the group comprising: - mono- or dicarboxylic acids, optionally oxidized, saturated or unsaturated, their esters and their salts, phosphoric, sulfonic and phosphonic acids, their esters with alcohols and their alkali, alkaline earth metal, zinc, aluminum and / or organic amine salts, - cyclic or acyclic compounds of group comprising lactones, ketones, aldehydes, amides and acetals, - higher, primary or secondary, cyclic or acyclic alcohols, optionally polyalkoxylated, with hydrocarbon chain having at least 10 carbon atoms, - linear aliphatic hydrocarbons and / or sparsely branched, in particular paraffins and isoparaffins, - polyolefins and their copolymers with low molecular weights of 3000 to 20,000 g / mole, - polyglycols, especially polyethylene glycols

  molecular weight from 2000 to 10,000 g / mole.

  6. Stopper according to claim 4, characterized in that it uses a composition or premix whose structuring agent is chosen from the group comprising resinous compounds having a polymeric and / or cyclic structure and which may contain, in proportion minority, aromatic derivatives and

cyclic terpenes.

  7. Stopper according to one of claims 1 to 6,

  characterized by the fact that it uses a composition or premix, the structuring agent of which is chosen from the group of those identified in Table A below and some of which are waxes of natural or synthetic origin:

BOARD

  Origin Chemical nature Name Density to Index of majority agent of fusion agent 25 C ASTM penetration to structuring structuring agent (C) D 1298 25 C ASTM D 1321 Ester (carnauba cirotate 8386 0.995 myricyl ) Natural Ester (palmitate Wax 625 myricyl 0.955) of bees Paraffinic hydrocarbons Paraffin 50-60 0.900 15 (mixture) Isoparaffinic mineral hydrocarbons cristaleine 69 0.930 29 and naphthenic Aliphatic hydrocarbons Petrololatum 70-72 0.910 / 20 C 43-45

(mixed) _.

  Polyethylene Wax 0.930 6.5 ____ ____ ____ _ po yéth l8n 0.930 6.5

Hydrocarbons Micro wax

  isoparaffinicscrystalline 85 - 13 oxidized oxidized Synthetic Phosphoric ester of fatty alcohols - 83-89 0.998 C / ClC18 Polyethylene glycol Polyethylene - 5759 1.11

glyco 40W 57'59 1, 112/99 C -

_______ glycol 4000 ___ _

  8. Cap according to one of claims 1 to 7,

  characterized by the fact that it uses a composition or premix comprising at least one volatile corrosion inhibitor chosen from the group comprising: - nitrogen derivatives and in particular, on the one hand, aliphatic, aromatic, acyclic or cyclic amines of which dicyclohexylamine, cyclohexylamine, morpholine, diisopropylamine and benzylamine, their organic salts including benzoates, carbamates, laurates, caprylates, succinates or minerals including nitrites, nitrates, carbonates, phosphates, phosphites and, on the other hand, heterocycles including imidazole and its derivatives,

  triazoles and their derivatives, as well as hexamethylene-

  tetramine, - the nitrogen-oxide derivatives including the alkali or alkaline-earth metal salts of nitrous acid and - the benzo derivatives of these metals such as

sodium benzoate.

  9. Cap according to one of claims 1 to 8,

  characterized by the fact that it consists of at least one polymer which forms at least 50% by weight in its constitution and which can be chosen from those of the group comprising: - polyolefins including polyethylenes, polypropylene, polybutene and their copolymers with one or more unsaturated monomers including vinyl acetate, acrylic acid and its esters with short carbon-chain alcohols, - polyvinyl chloride and its copolymers, acrylic copolymers and their derivatives, and

  - polyamides, polystyrenes, polycarbo-

  nates, polyesters, polyurethanes, rubbers including natural rubber, styrene-butadiene and

polychloroprene.

  10. Stopper according to one of claims 1 to 9,

  characterized by the fact that it is implemented by any suitable process including molding, injection molding,

extrusion or thermoforming.

  11. Use of plugs according to one of

  claims 1 to 10 for the protection of the parties

  internal hollow metal parts against corrosion.