CLEANING COMPOSITION FOR INDUSTRIAL COATING LINE

Abstract

1) Cleaning composition comprising: from 5% to 99% of a thermoplastic polymer which does not react with moisture (a), from 1% to 15% of a monofunctional silane compound (b); from 0% to 94% of a compound (c) chosen from a plasticizer (c1), an oil (c2) or a tackifying resin (c3); said composition being homogeneous and having a Brookfield viscosity, measured at 100 C., within the range extending from 20 to 200 000 mPa.Math.s.

2) Process for cleaning the walls of items of industrial equipment which are coated with a layer of composition C comprising a polymer P having alkoxysilane groups, said process comprising the mixing of said composition C with the cleaning composition according to 1).

Claims

1. A cleaning composition comprising, on the basis of the total weight of said composition: from 5% to 99% by weight of a thermoplastic polymer which does not react with moisture (a) chosen from: polyurethanes having hydroxyl or alkyl end groups; polyamides; polyesters; ethylene-based copolymers; amorphous poly(-olefin)s, polybutadiene, polyisoprene; block polyolefins; styrene block copolymers; acrylic copolymers; polymeric alcohols obtained by oxidation of -olefins; from 1% to 15% by weight of a silane compound (b) comprising a single alkoxysilane group; from 0% to 94% by weight of a compound (c) chosen from a plasticizer (c1), an oil (c2) or a tackifying resin (c3); said composition being homogeneous and having a Brookfield viscosity, measured at 100 C. according to the standard ASTM D 3236, within the range extending from 20 to 200 000 mPa.Math.s.

2. The composition as claimed in claim 1, characterized in that the thermoplastic polymer (a) is chosen from polyurethanes, polyamides, polyesters, ethylene-based copolymers, acrylic copolymers and polymeric alcohols obtained by oxidation of -olefins.

3. The composition as claimed in claim 1, characterized in that the thermoplastic polymer (a) is chosen from copolymers based on ethylene and vinyl acetate and polyurethanes having hydroxyl end groups.

4. The composition as claimed in claim 1, characterized in that the alkoxysilane group of the silane compound (b) is of formula (I):
Si(R.sup.1).sub.n(OR.sup.2).sub.3-n(I) in which: R.sup.1 and R.sup.2, which are identical or different, each represent a linear or branched alkyl radical of 1 to 4 carbon atoms, optionally interrupted by an oxygen atom, with in addition the possibility, when there are several R.sup.2 radicals, for the latter, which are identical or different, to form a ring; n is an integer equal to 0, 1 or 2.

5. The composition as claimed in claim 1, characterized in that the silane compound (b) is chosen from the compounds of following formulae:
R.sup.4SiR.sup.1.sub.n(OR.sup.2).sub.3-n(II)
R.sup.5C(O)OR.sup.3SiR.sup.1.sub.n(OR.sup.2).sub.3-n(III)
R.sup.6C(O)N(R.sup.8)R.sup.3SiR.sup.1.sub.n(OR.sup.2).sub.3-n(IV)
R.sup.7OC(O)NHR.sup.3SiR.sup.1.sub.n(OR.sup.2).sub.3-n(V)
(R.sup.7)(R.sup.9)NC(O)NHR.sup.3SiR.sup.1.sub.n(OR.sup.2).sub.3-n(VI) in which: R.sup.1, R.sup.2 and n are identical or different, each represent a linear or branched alkyl radical of 1 to 4 carbon atoms, optionally interrupted by an oxygen atom, with in addition the possibility, when there are several R.sup.2 radicals, for the latter, which are identical or different, to form a ring; n is an integer equal to 0, 1 or 2; R.sup.3 represents a divalent alkylene radical, which is preferably linear, comprising from 1 to 4 carbon atoms; R.sup.4 represents a linear or branched alkyl or alkenyl radical comprising from 2 to 60 carbon atoms; R.sup.5, R.sup.6 and R.sup.7 represent, each taken independently, a linear or branched alkyl or alkenyl, aromatic or alicyclic radical comprising from 1 to 60 carbon atoms; R.sup.8 represents a linear or branched alkyl or alkenyl, aromatic or alicyclic radical comprising from 1 to 6 carbon atoms; R.sup.9 represents a hydrogen atom, a linear or branched alkyl or alkenyl radical, an aromatic radical or an alicyclic radical comprising from 1 to 60 carbon atoms.

6. The composition as claimed in claim 1, characterized in that the compound (c) is a plasticizer (c1) chosen from benzoates or phthalates.

7. The composition as claimed in claim 1, characterized in that the compound (c) is a tackifying resin (c3), with a number-average molar mass Mn of between 200 Da and 10 kDa.

8. The composition as claimed in claim 7, characterized in that the tackifying resin (c3) is chosen from: (i) resins obtained by polymerization of terpene hydrocarbons and phenols, in the presence of a Friedel-Crafts catalyst; (ii) resins obtained by a process comprising the polymerization of -methylstyrene, it also being possible for said process to comprise a reaction with phenols; (iii) rosins of natural origin or modified rosins, such as, for example, the rosin extracted from pine gum, wood rosin extracted from tree roots and their derivatives which are hydrogenated, dimerized, polymerized or esterified with monoalcohols or polyols, such as glycerol; (iv) resins obtained by hydrogenation, polymerization or copolymerization (with an aromatic hydrocarbon) of mixtures of unsaturated aliphatic hydrocarbons having approximately 5, 9 or 10 carbon atoms resulting from petroleum fractions; (v) terpene resins generally resulting from the polymerization of terpene hydrocarbons, such as, for example, monoterpene (or pinene), in the presence of Friedel-Crafts catalysts; (vi) copolymers based on natural terpenes, for example styrene/terpene, -methylstyrene/terpene and vinyltoluene/terpene; or else (vii) acrylic resins having a viscosity at 100 C. of less than 100 Pa.Math.s.

9. The composition as claimed in claim 8, characterized in that use is made, as resin (c3), of a resin chosen from those of type (i).

10. The composition as claimed in claim 1, characterized in that its viscosity, measured at 100 C., is within the range extending from 500 to 50 000 mPa.Math.s, preferably within the range extending from 4000 to 20 000 mPa.Math.s.

11. A process for cleaning the walls of items of industrial equipment which are coated with a layer of composition C comprising a polymer P having alkoxysilane groups, said process comprising the mixing of said composition C with a cleaning composition as defined in claim 1.

12. The process as claimed in claim 11, characterized in that the main chain of the polymer P is chosen from a polyether chain, a polyurethane chain, a chain comprising polyurethane/polyether and polyurethane/polyester blocks, and in that an alkoxysilane group is grafted to each of the two ends of said main chain.

13. The process as claimed in claim 11, characterized in that the composition C comprises, in addition to the polymer P, a tackifying resin and a crosslinking catalyst.

14. The process as claimed in claim 11, characterized in that the items of industrial equipment are included in an industrial line for coating with the composition C.

15. The process as claimed in claim 14, characterized in that the industrial coating line is fed in semicontinuous mode using, as storage tank, the drum for packaging the composition C and in that said process comprises, after the operation under continuous conditions of the line and before it is shut down, a stage of feeding the latter with a drum containing the cleaning composition, as replacement for the drum containing the composition C.

Description

EXAMPLE 1: CLEANING COMPOSITION BASED ON EVA

[0129] 1. Preparation:

[0130] The composition appearing in table 1 is prepared by introducing first of all the plasticizer (c1) into an electrically heated glass reactor equipped with a mechanical stirrer and connected to a vacuum pump. The plasticizer is kept stirred and under vacuum until the temperature reaches 145 C.

[0131] The EVA, in the form of granules, is then charged, slowly and with stirring, as thermoplastic polymer (a). Stirring is maintained and the vacuum is re-established until a homogeneous liquid mixture is obtained, i.e. for approximately 60 minutes.

[0132] The liquid mixture is then cooled until a temperature of 85 C. is reached and then the reactor is brought back to atmospheric pressure by injection of dry nitrogen (containing less than 3 ppm of water). The monofunctional silane compound (b) shown in table 1 is subsequently charged under the same nitrogen atmosphere. Once this charging is complete, the vacuum and the stirring are re-established in the reactor so as to homogenize the mixture, i.e. for approximately 15 minutes.

[0133] The viscosity of the composition obtained is measured at 100 C. by means of a Brookfield viscometer provided with an A27 needle rotating at a speed of 10 rev/minute and according to the standard ASTM D 3236. The value obtained is shown in table 1.

[0134] The composition obtained is finally packaged in a cylindrical aluminum cartridge, with a capacity of 350 ml, which is hermetically closed with the exclusion of air by crimping of the disk-shaped bottom.

[0135] 2. Test of Usefulness for Cleaning:

[0136] 2.1. Description of the Test and Result:

[0137] The test used to quantify the usefulness of the composition prepared in 1. for the cleaning of the walls of a reactor which are coated with a heat-crosslinkable adhesive composition comprising a polymer having end groups of alkoxysilane type is described below.

[0138] Prior to this test, the amount of a heat-crosslinkable adhesive composition of reference R necessary for the packaging thereof in a cartridge (identical to that described above) is prepared, which composition comprises: [0139] 53.7% by weight of a polyurethane obtained from a polypropylene glycol (or poly(isopropoxy)diol) and comprising two trimethoxysilane terminal groups, [0140] 44.7% of a tackifying resin obtained by polymerization of terpene hydrocarbons and phenols, in the presence of a Friedel-Crafts catalyst, and [0141] 1.1% of a crosslinking catalyst.

[0142] The composition R is that described in example 2 of the application WO 2009/106699 and reference is made to this document for the details relating to the nature of its ingredients and the methods for its preparation.

[0143] The two hermetically closed aluminum cartridges, respectively containing the composition of example 1 to be tested and the reference composition R, are first of all put on to preheat at a temperature of 100 C. for 2 hours.

[0144] A 500-ml glass reactor which is electrically heated and which is equipped with a mechanical stirrer adjustable in height, the temperature of which is maintained at 100 C. throughout the duration of the test, is used. This reactor is placed under a hood in a controlled atmosphere: temperature of 23 C. and relative humidity of 50%.

[0145] 50 grams of the reference composition R are introduced into the reactor. Immediately after this introduction, the reactor is closed and circulation of dry nitrogen (containing less than 3 ppm of water) is put in place for approximately 3 minutes. The mechanical stirrer is positioned in the reactor at a height such that it is not in contact with the composition R.

[0146] The circulation of nitrogen is halted, the reactor is opened and then 150 g of the composition of example 1 are introduced over a time of between 5 and 10 minutes. The reactor is then flushed with dry nitrogen (containing less than 3 ppm of water) for 5 seconds and the reactor is closed again. The mechanical stirrer is positioned at a height such that it is in contact with the composition resulting from this last introduction. Stirring is maintained at 30 revolutions/minute for 1 hour, the composition being in contact with the mixture of atmospheric air and nitrogen present in the reactor.

[0147] At the end of one hour, the presence in the reactor of a homogeneous composition in the form of a viscous liquid is observed. A sample of 12.5 g of said composition is withdrawn for measurement of the viscosity at 100 C. by means of a Brookfield viscometer equipped with an A27 needle rotating at a speed of 10 rev/minute. The value is recorded 20 minutes after introduction of the composition into the viscometer and the value obtained is shown in table 1.

[0148] After the withdrawal of the 12.5 grams of composition intended for the measurement of the viscosity, the reactor is inclined so as to cause its contents to flow, by gravity, into a container in order to be discarded.

[0149] After cooling the reactor to ambient temperature, the product remaining on the walls of the reactor is subsequently removed manually by simple wiping by means of a rag made of nonwoven material, this wiping with a clean rag being repeated if necessary several times until a residue adhering to the wall of the reactor is obtained which can no longer be removed by said wiping. Washing with the solvent of methyl ethyl ketone type is then necessary in order to remove said residue and to obtain a clean reactor.

[0150] The usefulness of the composition prepared in 1) for the cleaning of walls which are coated with the composition R is evaluated by the amount of product remaining in the reactor which is removed after wiping the reactor with said rag and before washing off the adherent residual product with the solvent.

[0151] This amount is estimated according to the following grading:

[0152] + means that an amount of approximately 50% of the remaining product has been removed

[0153] ++ means that an amount of approximately 75% of the residual product has been removed

[0154] +++ means that an amount of approximately 95% of the residual product has been removed

[0155] The grading obtained is shown in table 1.

[0156] The results obtained show that the composition prepared in 1. is suitable for the cleaning of the walls of the reactor which are coated with the reference heat-crosslinkable adhesive composition R.

[0157] 2.2. Control Test:

[0158] The procedure described in 2.1. is repeated, except that, after the introduction into the reactor of the reference composition R and flushing with nitrogen, the reactor is opened for approximately 7 minutes without introducing cleaning composition, so that, for 1 hour, the composition R remains alone in contact with the mixture of atmospheric air and nitrogen present in the reactor, without any stirring.

[0159] At the end of one hour, the presence in the reactor of a solid layer, which represents approximately 50% by volume of the composition R (also described as skin) and which adheres very strongly to the walls and to the stirrer, is observed. Said layer corresponds to the crosslinking of the polyurethane having an alkoxysilane group included in the composition R. The cleaning in this case can only be carried out after dipping the glass reactor and the stirrer in solvent of methyl ethyl ketone type for at least 24 hours.

EXAMPLE 2 (COMPARATIVE)

[0160] An EVA-based composition identical to that of example 1, with the exception of the content of monofunctional silane (b) of 10%, which is reduced to 0, and of the content of plasticizer (c), which is brought from 60% to 70%, is prepared.

[0161] For this, the stages shown in the procedure of point 1. of example 1 are repeated, the stage of charging the monofunctional silane (b) simply being omitted and viscosity being measured after obtaining the homogeneous liquid mixture of the plasticizer (c1) and of the EVA (a).

[0162] The viscosity at 100 C. of the composition obtained is shown in table 1.

[0163] The test of usefulness for cleaning of this composition is carried out by repeating the procedure shown in 2. for example 1.

[0164] After introducing 150 g of said cleaning composition into the reactor and stirring the composition resulting from the mixing thereof with the composition R, there is observed, in less than one hour, the formation of a product in the form of an extremely viscous gel, the viscosity of which cannot be measured by means of the Brookfield viscometer used in example 1 and which adheres very strongly to the wall of the reactor and to the stirrer. The presence of this product is shown in table 1 by the comment gel.

[0165] Once the contents of the reactor have been poured into a container in order to be discarded, it is not possible to remove, by wiping with the rag, the product which remains in the reactor in the form of said gel adhering to its walls and to the stirrer. Only washing with the solvent of methyl ethyl ketone type makes it possible to remove said residue and to obtain a clean reactor. This is indicated by the grading in table 1.

[0166] This composition is not suitable for the cleaning of the walls of the reactor brought into contact with the reference composition R.

EXAMPLES 3-8

[0167] Example 1 is repeated for the compositions having the natures and the contents of ingredients shown in table 1, which also reveals the viscosities at 100 C. of the compositions prepared and also the results obtained for the test of usefulness for cleaning of said compositions.

EXAMPLE 9: CLEANING COMPOSITION BASED ON A POLYURETHANE HAVING HYDROXYL END GROUPS OBTAINED FROM POLYCAPROLACTONE

[0168] The procedure shown for example 1 in point 1. is repeated, so as to prepare a cleaning composition consisting of: [0169] 25% by weight of Pearlbond 100, as thermoplastic polymer (a), introduced in the form of granules, [0170] 5% by weight of Geniosil XL 63 as monofunctional silane compound (b); and [0171] 70% by weight of Uniplex 512 as plasticizer (c1).

[0172] The Brookfield viscosity measured at 100 C. on said composition thus prepared is 2500 mPa.Math.s.

[0173] The test of usefulness for cleaning is also carried out. The viscosity at 100 C., measured on the homogeneous composition obtained after mixing for 1 hour, is 3000 mPa.Math.s. The grade associated with the test is: ++.

TABLE-US-00001 TABLE 1 EVA-based compositions Content as % by weight Ex. 2 Ingredients Ex. 1 (comparative) Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Ex. 8 (a) Evathane 40-55 30 30 30 30 30 30 30 30 (b) Silquest Y 15866 5 Silquest A 174 5 Geniosil XL 63 10 0 5 1 5 Geniosil XL 33 5 (c1) Uniplex 512 Benzoflex 9-88 60 70 65 69 65 K-Flex 850S 65 65 Benzoflex 2088 65 Viscosity at 100 C. (mPa .Math. s) 4500 9801 7000 9801 6500 8500 7100 8900 Test of usefulness for cleaning: Viscosity at 100 C. (mPa .Math. s) 4300 Gel 6670 25 000 7100 9400 7850 9900 grade + + + +++ + + +++

EXAMPLE 10 (COMPARATIVE)

[0174] Example 9 is repeated so as to prepare a composition identical to that of said example, with the exception of the content of monofunctional silane (b) of 5%, which is reduced to 0, and of the content of plasticizer (c1), which is brought from 70% to 75%. The preparation is carried out in accordance with the protocol of example 2.

[0175] The Brookfield viscosity measured at 100 C. on said composition thus prepared is 4200 mPa.Math.s.

[0176] Carrying out the test of usefulness for cleaning leads to the same result as example 2, with formation of a gel and impossibility of removing, by wiping with the rag, the product remaining in the reactor.

EXAMPLE A (REFERENCE): PREPARATION OF A THERMOPLASTIC POLYURETHANE HAVING HYDROXYL END GROUPS

[0177] The following compounds are used for the purpose of this preparation: [0178] isophorone diisocyanate (IPDI), available from Evonik Industries under the trade name Vestanat IPDI and exhibiting a content of NCO group of 37.6% by weight; [0179] a linear polyether polyol Acclaim 18200 N, available from Bayer and exhibiting a hydroxyl number of 6.0 mg KOH/g; and [0180] a catalyst of zinc-based organometallic type, available from OMG Borchers GmbH under the name Borchi KAT 0244.

[0181] The polyether polyol is introduced into a glass reactor equipped with a mechanical stirrer and connected to a vacuum pump, and heating is carried out under vacuum so as to reach a temperature of 85 C. until a residual water content of said polyether of less than 150 ppm is obtained, said content being measured by the Karl Fischer method. These conditions are maintained for an additional 30 minutes and then the system is brought back to atmospheric pressure under circulation of dry nitrogen containing less than 3 ppm of water.

[0182] The diisocyanate is then slowly charged and the catalyst is introduced 20 minutes after the end of the addition of the diisocyanate. The reaction medium is maintained at 85 C., under stirring and flushing with nitrogen, for approximately 90 minutes, until the complete disappearance of the NCO functional groups measured by infrared spectroscopy.

[0183] The respective amounts of polyether polyol and diisocyanate introduced correspond to the contents by weight shown in table 2 and to a ratio: number of NCO equivalents/number of OH equivalents equal to 0.5.

[0184] The polyurethane obtained exists in the form of a very viscous liquid which is packaged in an aluminum cartridge.

TABLE-US-00002 TABLE 2 (reference): polyurethanes obtained from polyether polyols Content by weight of reactants per 100 g of polyurethane formed Ex. A Ex. B Reactants (reference) (reference) Isocyanate Vestanat IPDI 0.57 Isonate M 125 5.08 Polyether polyol Acclaim 18200 N 99.33 Voranol EP 1900 94.82 Catalyst Borchi KAT 0244 0.10 0.10

EXAMPLES 11 and 12: CLEANING COMPOSITION BASED ON THE POLYURETHANE HAVING HYDROXYL END GROUPS OF EXAMPLE A

[0185] The procedure shown for example 1 in point 1. is repeated, so as to prepare a cleaning composition having the natures and the contents of ingredients shown in table 3. For this, after preheating to approximately 60 C. the aluminum cartridge containing the polyurethane of example A, the polyurethane is charged to the reactor as thermoplastic polymer (a).

[0186] The results obtained are shown in table 3.

EXAMPLE 13: CLEANING COMPOSITION BASED ON THE POLYURETHANE HAVING HYDROXYL END GROUPS OF EXAMPLE A

[0187] The procedure shown for examples 11 and 12 is repeated, the plasticizer (c1) being replaced with the tackifying resin Dertophene H150 (c3), so to prepare a cleaning composition having the content of ingredients shown in table 3.

[0188] The results obtained are shown in table 3.

TABLE-US-00003 TABLE 3 compositions based on the polyurethane of example A Content as % by weight Ex. 14 Ingredients Ex. 11 Ex. 12 Ex. 13 (comparative) (a) Polyurethane Example A 65 60 39 40 (b) Geniosil XL 63 5 5 6 0 (c) Uniplex 512 35 Benzoflex 2088 30 (d) Dertophene H150 55 60 Viscosity at 100 C. (mPa .Math. s) 19 950 11 200 19 000 26 000 Test of usefulness for cleaning: Viscosity at 100 C. (mPa .Math. s) 18 000 12 000 19 500 Gel grade + +++ ++

EXAMPLE 14 (COMPARATIVE): COMPOSITION BASED ON THE POLYURETHANE HAVING HYDROXYL END GROUPS OF EXAMPLE A

[0189] Example 9 is repeated while omitting the monofunctional silane (b) and with the contents of ingredients shown in table 3.

[0190] The results obtained are shown in table 3.

EXAMPLE B (REFERENCE): PREPARATION OF A THERMOPLASTIC POLYURETHANE HAVING HYDROXYL END GROUPS

[0191] The following compounds are used for the purpose of this preparation: [0192] 4,4-diphenylmethane diisocyanate (4,4-MDI), available from Dow Chemical under the trade name Isonate M 125 and exhibiting a content of NCO group of 33.6% by weight; [0193] a linear polyether polyol Voranol EP 1900, available from Bayer and exhibiting a hydroxyl number of 28.5 mg KOH/g; and [0194] the same catalyst as that of example A.

[0195] The polyurethane is prepared by repeating the procedure of example A.

[0196] The respective amounts of polyether polyol and of isocyanate introduced correspond to the contents by weight shown in table 2 and to a ratio: number of NCO equivalents/number of OH equivalents equal to 0.8.

EXAMPLES 15-17: CLEANING COMPOSITION BASED ON THE POLYURETHANE HAVING HYDROXYL END GROUPS OF EXAMPLE B

[0197] The monofunctional silane (b) is also added, under the conditions described in example 1, to the glass reactor in which the polyurethane of example B was prepared, so as to obtain the cleaning composition having the natures and the contents of ingredients shown in table 4.

[0198] The results obtained are shown in table 4.

EXAMPLE 18 (COMPARATIVE): Composition Based on the Polyurethane Having Hydroxyl End Groups of Example B

[0199] Examples 15-17 are repeated without also adding monofunctional silane (b).

[0200] The results obtained are shown in table 4.

TABLE-US-00004 TABLE 4 compositions based on the polyurethane of example B Content as % by weight Ex. 18 Ingredients Ex. 15 Ex. 16 Ex. 17 (comparative) (a) Polyurethane Example B 95 95 97.5 100 (b) Geniosil XL 33 5 0 Geniosil XL 63 5 2.5 0 Viscosity at 100 C. (mPa .Math. s) 8800 8800 9800 8600 Test of usefulness for cleaning: Viscosity at 100 C. (mPa .Math. s) 10 300 10 000 17 000 Gel grade +++ + +++