COMPOSITION POLYISOCYANATE BIURET

Abstract

In the field of polyisocyanate compositions for the production of coatings and adhesives, the disclosed composition combines a polyisocyanate compound with biuret motifs, a protic, polar reactive diluent compound, one of the addition compounds thereof, and an aprotic reactive diluent compound. Also disclosed is a method for producing the composition, and to the use thereof for producing a coating or an adhesive.

Claims

1. Composition with an average isocyanate functionality in excess of 2.5, comprising: at least one polyisocyanate compound with biuret motifs (a); at least one polar proteic reactive diluent compound (b), chosen from amongst the polyisocyanate compounds with allophanate motifs, with viscosity, measured at 25? C., of less than 500 mPa.Math.s; at least one additional compound (c) with a compound (a) and a compound (b) and at least one aproteic reactive diluent compound (d).

2. Composition according to claim 1 comprising 40-50% by weight compound (a) or 40-60% by weight compound (a), or 40-70% by weight compound (a) or 40-80% by weight compound (a) or 40-90% by weight compound (a); 2-50% by weight or 5-50% by weight compound (b); 0.5-20% by weight or 0.5-10% by weight compound (c) and 1-20% by weight compound (d).

3. Composition according to claim 1, for which viscosity measured at 25? C. is less than 30,000 mPa.Math.s.

4. Composition according to claim 1, with average isocyanate functionality in excess of 2.75.

5. Composition according to claim 1, independently containing at least one (a) compound and at least (b) compound prepared from an isocyanate monomer component chosen from amongst MPDI, HDI, tetramethylene diisocyanate, pentamethylene diisocyanate, octamethylene diisocyanate, butylene diisocyanate, octylene diisocyanate, trimethylhexane diisocyanate, dodecane diisocyanate, undecane diisocyanate, 2,2,4-tri-methyl-hexamethylene diisocyanate, 2,4,4-tri-methyl-hexamethylene diisocyanate, 1,8-diisocyanato-4-isocyanato-methyl octane, 1-decane triisocyanate, IPDI, XDI, MXDI, PXDI, H.sub.12MDI, H.sub.6TDI, diisocyanate lysine derivatives, BICs and NBDIs.

6. Composition according to claim 1, within which the (b) compound is a formula (I) compound ##STR00003## within which R.sup.1 and R.sup.2, identical or different, independently represent a C.sub.2-C.sub.20 alkyl group, linear, cyclic or branched, containing at least one isocyanate function; R.sup.3 independently represents a C.sub.5-C.sub.10 heterocycloalkyl group; a C.sub.5-C.sub.10 aromatic group; a C.sub.5-C.sub.10 alkyl-aryl group; a C.sub.1-C.sub.20 alkyl group, linear, cyclic or branched.

7. Composition according to claim 6, in which in which the (b) compound is a formula (I) compound within which R.sup.1 and R.sup.2, identical or different, independently represent a C.sub.2-C.sub.8 alkyl group, linear or branched, containing an isocyanate function; R.sup.3 independently represents a C.sub.3-C.sub.8 alkyl group, linear or branched.

8. Composition according to claim 1, in which the (d) compound is chosen from amongst a compound with formula (IV), a compound with formula (V), a compound with formula (VI) and a compound with formula (VII) ##STR00004## within which R.sup.6 and R.sup.7, identical or different, independently represent a C.sub.2-C.sub.20 alkyl group, linear, cyclic or branched, containing at least one isocyanate function; R.sup.8, R.sup.9, R.sup.11, R.sup.12, R.sup.13 R.sup.14 and R.sup.15, identical or different, independently represent a C.sub.2-C.sub.20 alkyl group, linear, cyclic or branched.

9. Procedure for preparing a composition according to claim 1, containing the following stages: 1) preparation of at least one polyisocyanate compound with biuret motifs (a); 2) preparation of at least one polar, proteic reactive diluent compound (b), chosen from amongst the polyisocyanate compounds with allophanate motifs, with viscosity, measured at 25? C., of less than 500 mPa.Math.s; 3) preparation of at least one additional compound (c); 4) preparation of at least one polar and proteic reactive diluent compound (d); then 5) separation of excess isocyanate monomer.

10. Procedure according to claim 9 within which stage 1), 2) or 4) may be carried out first or within which stages 1) and 2), stages 2) and 3), stages 3) and 4), or stages 1), 2), 3) and 4) may be carried out simultaneously.

11. Procedure according to claim 9 within which stage 1) is carried out in the presence of a buretisation catalyst chosen from amongst metallic carboxylates, metallic alkyl carboxylates, dialkyl phosphates, phosphate esters and diesters, butyl esters, 2-ethyl hexyl esters, decyl esters, dodecyl esters and neodecanoyl esters.

12. Procedure according to claim 9, within which stage 2) is carried out in the presence of an allophanatation catalyst chosen from amongst carboxylates of bismuth, alkylcarboxylates of bismuth, carboxylates of magnesium, alkylcarboxylates of magnesium, carboxylates of zinc, alkylcarboxylates of zinc, carboxylates of zirconium and alkylcarboxylates of zirconium.

13. Procedure according to claim 9 within which stages 1) and 2) are carried out in the presence of a single catalyst chosen from amongst carboxylates of zinc and alkylcarboxylates of zinc.

14. Procedure according to claim 9 within which the total molar ratio of the catalyst(s)/number of OH functions is between 1.10.sup.?2 and 1.10.sup.?5.

15. Method of preparation of a coating or adhesive comprising a step of preparing the composition according to claim 1.

16. Method according to claim 15 for the preparation of a polyurethane, polyurea or poly(urea-urethane) coating.

17. Method according to claim 15 for the preparation of a polyurethane, polyurea or poly(urea-urethane) adhesive.

18. Composition according to claim 1, for which viscosity measured at 25? C. is less than 10,000 mPa.Math.s.

19. Composition according to claim 1, for which viscosity measured at 25? C. is lower than 5,000 mPa.Math.s.

20. Composition according to claim 1, for which viscosity measured at 25? C. is lower than 2,000 mPa.Math.s.

Description

EXAMPLE 1: PREPARATION OF LOW-VISCOSITY POLYISOCYANATE COMPOSITION USING A SINGLE CATALYST

[0112] In this test, zinc bi-2-ethyl hexanoate is used as a single catalyst for synthesis of the (b) compound and the (a) compounds.

[0113] In a double-envelope tricol reactor, equipped with mechanical stirring, a cooler and an addition bulb, 600 g (3.571 mol) of hexamethylene diisocyanate (HDI) is added in an inert atmosphere at ambient temperature. The temperature of the reaction milieu is raised to 110? C. 0.13 g of zinc bi-2 ethyl hexanoate, 80% by weight in white spirit is added to 4.26 g (57.6 mmol) of 1-butanol. This catalyst formulation is added to the reaction milieu. The temperature of the reaction milieu is raised to 130? C. and maintained for a further hour. The NCO titre of the reaction milieu is in the region of 1.15 mol for 100 g. It is observed by infra-red analysis that the reactive allophanate diluent of HDI and of n-butyl is formed. 6.6 g of liquid water is then added to the reactive medium in 1 hour. After the water is added, the temperature of the reaction milieu is raised to 150? C. After 2 hours of reaction at 150? C., the reaction is stopped by adding 0.670 g of acid dibutyl phosphate (3.18 mmol). The NCO titre of the reaction mass prior to distillation is 0.980 mol for 100 g of reaction milieu. 559.6 g of reaction mass is filtered to eliminate 0.37 g of solid impurities. The filtrate is then distilled in a vacuum at 140? C. to eliminate the excess HDI monomer. 169 g of polyisocyanate composition is obtained. The weighted output recovered is 30.2%.

[0114] The characteristics of the example 1 products obtained following distillation of the excess diisocyanate monomer used are shown in Table 1. The average NCO molar function is calculated on the basis of the composition analysed by gel permeation chromatography (GPC-IR).

TABLE-US-00001 TABLE 1 NCO Viscosity titre % mPas Average molar HDI transformation weight 25? C. functionality, NCO rate, % weight 22.9 1066 3.01 32.5

[0115] The polyisocyanate composition is analysed by gel permeation chromatography combined with infra-red detection. It contains biuret-structured oligomers, a polar proteic reactive diluent of the allophanate type, at least one reaction compound containing an allophanate structure bonded covalently to a biuret structure and an aproteic reactive diluent of the uretidine dione type. The distribution of the compounds is shown in Table 2.

TABLE-US-00002 TABLE 2 Type of Compound of Example 1 % compound composition weight Monomer HDI 0.25 HDI and butyl carbamate 0.2 (d) HDI uretidine dione (HDI 8 Dimer) (b) HDI and n-butyl allophanate 7.9 (a) Biuret-dimer, Biuret (n = 3, 74.4 n = 5, n > 5) (c) HDI and n-butyl biuret- 8.95 allophanate polyisocyanate derivatives

[0116] In the case of example 1, the molar fraction of allophanate functions of the (c) compounds is 0.024 for 169 g of composition.

[0117] It is calculated as follows:

Number of moles of alcohol compound (butanol) used?{Number of moles of (b) compounds (HDI and n-butyl allophanate) obtained in total mass of polyisocyanate composition in Example 1+number of moles of intermediate (b) compounds (butyl and HDI carbonate) obtained in total mass of polyisocyanate composition in Example 1}=0.0576?{((7.9 g/410)*169/100)+((0.2/242)*169/100)}=0.024

EXAMPLE 2: PREPARATION OF LOW-VISCOSITY BIURET-BASE POLYISOCYANATE COMPOSITION WITH ANOTHER SINGLE CATALYST

[0118] Procedure is as for Example 1 but uses zinc bi-neodecanoate (bNZ) as reaction catalyst instead and in place of zinc bi-2-ethyl hexanoate. Zinc bi-neodecanoate presents a better toxicity profile. The quantities of reagents used are shown in Table 3.

TABLE-US-00003 TABLE 3 Reagent HDI Water 1-butanol bNZ (dry extract) Quantity in g 600 6.6 4.26 0.15

[0119] The molar ratios are shown in Table 4.

TABLE-US-00004 TABLE 4 NCO/OH NCO/ alcohol water bNZ/NCO bNZ/OH alcohol 124 19.5 52.10.sup.?6 0.0064

[0120] The quantity of polyisocyanate recovered following reaction and distillation of the diisocyanate monomer is 176 g, corresponding to a recovered weighted output of 31.5%. The quantity of insoluble substances present before distillation is 0.35 g against 562 g of reaction mass involved in distillation. The NCO titre of the reaction milieu before distillation is 0.985 mol for 100 g.

[0121] The characteristics of the products obtained after distillation of the excess diisocyanate used are shown in Table 5. The average NCO molar function is calculated on the basis of the composition analysed by gel permeation chromatography (GPC-IR).

TABLE-US-00005 TABLE 5 NCO Viscosity titre % mPas Average molar HDI transformation weight 25? C. functionality, NCO rate, % weight 22.9 1070 2.99 33.4

[0122] The distribution of compounds in the final composition is shown in Table 6.

TABLE-US-00006 TABLE 6 Type of compound Compound of Example 2 composition % weight HDI monomer 0.15 Carbamate of HDI and butyl and HAI 0.2 and isopropyl (d) HDI dione uretidine (HDI dimer) 8 (b) Allophanate of HDI and of n-butyl 7.9 (a) Dimer-biuret, Biuret (n = 3, n = 5, n > 5) 76.1 (c) HDI and n-butyl biuret-allophanate 7.65 polyisocyanate derivatives

[0123] In the case of example 2, the molar fraction of allophanate functions of the (c) compounds is 0.022 for 176 g of composition. The same type of calculation is carried out as for Example 1.

EXAMPLE 3: PREPARATION OF LOW-VISCOSITY POLYISOCYANATE COMPOSITION WITH MODIFIED OPERATING CONDITIONS

[0124] Procedure is as for Example 2; the quantities of reagents are the same but the operating conditions are modified. The alcoholic formulation of the catalyst is added to the reaction milieu containing the HDI at ambient temperature. The temperature of the reaction milieu is raised from ambient temperature to 150? C. in 1 hour. The water is injected within 1 hour of the temperature reaching 130? C. The reaction milieu is maintained at 150? C. 2 hours after injection of the total quantity of water.

[0125] Under these conditions, the NCO titre of the reaction mass is 1.165 mol of NCO for 100 g before injection of the water commences. The NCO titre of the reaction milieu before distillation is 0.978 mol for 100 g. The HDI transformation rate is 32% weight. 454 g of reaction milieu is filtered via millipore and then purified by distillation of the HDI monomer. The quantity of insoluble substances obtained by filtering the reaction mass before distillation is 0.54 g. After distillation, 149 g of low-viscosity polyisocyanate with biuret motifs is recovered, making a recovered weighted output of 33%. The characteristics of the products obtained after distillation are shown in Table 7.

TABLE-US-00007 TABLE 7 NCO titre % Viscosity mPas HDI transformation weight 25? C. rate, % 22.72 1,371 32

[0126] The distribution of compounds in the final composition is shown in Table 8.

TABLE-US-00008 TABLE 8 Type of % compound Compound of Example 3 composition weight Monomer HDI 0.2 HDI urea 0.1 HDI and n-butyl carbamate 0.2 (d) HDI uretidine dione (HDI Dimer) 7.1 (b) HDI and n-butyl allophanate 9.7 (a) Dimer-biuret, Biuret (n = 3, n = 5, n > 5) 73.9 (c) HDI and n-butyl biuret-allophanate 9 polyisocyanate derivatives

[0127] In the case of example 3, the molar fraction of allophanate functions of the (c) compounds is 0.022 for 149 g of composition. The same type of calculation is carried out as for Example 1.

EXAMPLE 4: PREPARATION OF LOW-VISCOSITY POLYISOCYANATE COMPOSITION WITH OTHER MODIFIED OPERATING CONDITIONS

[0128] Procedure is as for Example 3; the quantities of reagents are the same but the operating conditions are modified. The alcoholic formulation of the catalyst is added to the reaction milieu containing the HDI at ambient temperature. The temperature of the reaction milieu is raised from ambient temperature to 150? C. in 1 hour. The water is injected 1 hour after the temperature reaches 130? C., that is, once a 1-hour steady phase at 130? C. has passed. The reaction milieu is kept at 150? C. for 3 hours after all the water is injected. Under these conditions, the NCO titre of the reaction mass is 1.154 mol of NCO for 100 g before injection of the water commences. The NCO titre of the reaction milieu before distillation is 0.980 mol for 100 g. The HDI transformation rate is 32% weight. 567 g of reaction milieu is filtered via millipore and then purified by distillation of the HDI monomer. The quantity of insoluble substances obtained by filtering the reaction mass before distillation is 0.44 g. After distillation, 186 g of low-viscosity polyisocyanate with biuret motifs is recovered, making a recovered weighted output of 33%. The characteristics of the products obtained after distillation are shown in Table 9.

TABLE-US-00009 TABLE 9 NCO titre % Viscosity mPas HDI transformation weight 25? C. rate, % 22.9 1,157 32

[0129] The distribution of compounds in the final composition is shown in Table 10.

TABLE-US-00010 TABLE 10 Type of % compound Compound from composition in example 4 weight Monomer HDI 0.3 HDI urea 0.1 HDI and n-butyl carbamate 0.1 (d) HDI uretidine dione (HDI Dimer) 8.5 (b) HDI and n-butyl allophanate 10.3 (a) Dimer-biuret, Biuret (n = 3, n = 5, n > 5) 70 (c) HDI and n-butyl biuret-allophanate 10.7 polyisocyanate derivatives

[0130] In the case of example 4, the molar fraction of allophanate functions of the (c) compounds is 0.020 for 186 g of composition. The same type of calculation is carried out as for Example 1.

EXAMPLE 5: PREPARATION OF LOW-VISCOSITY POLYISOCYANATE COMPOSITION WITH OTHER MODIFIED OPERATING CONDITIONS

[0131] Procedure is as for Example 3; the quantities of reagents are the same, but the operating conditions are modified. The alcoholic formulation of the catalyst is added to the reaction milieu containing the HDI at ambient temperature. The temperature of the reaction milieu is raised from ambient temperature to 150? C. in 1 hour. The water is injected within 1 hour of the temperature reaching 130? C. The reaction milieu is maintained at 150? C. 2 hours after injection of the total quantity of water.

[0132] Under these conditions, the NCO titre of the reaction mass is 1.167 mol of NCO for 100 g before injection of the water commences. The NCO titre of the reaction milieu before distillation is 0.968 mol for 100 g. The HDI transformation rate is 34% weight. 597 g of reaction milieu is filtered via millipore and then purified by distillation of the HDI monomer. The quantity of insoluble substances obtained by filtering the reaction mass before distillation is 0.37 g. After distillation, 189 g of low-viscosity polyisocyanate with biuret motifs is recovered, making a recovered weighted output of 33.5%. The characteristics of the products obtained after distillation are shown in Table 11.

TABLE-US-00011 TABLE 11 NCO titre % Viscosity mPas HDI transformation weight 25? C. rate, % 22.6 1,366 34

[0133] The distribution of compounds in the final composition is shown in Table 12.

TABLE-US-00012 TABLE 12 Type of % compound Compound of Example 5 composition weight Monomer HDI 0.5 HDI urea 0.2 HDI and n-butyl carbamate 0.2 (d) HDI uretidine dione (HDI Dimer) 8.1 (b) HDI and n-butyl allophanate 7.9 (a) Dimer-biuret, Biuret (n = 3, n = 5, n > 5) 72.9 (c) HDI and n-butyl biuret-allophanate 10.9 polyisocyanate derivatives

[0134] In the case of example 5, the molar fraction of allophanate functions of the (c) compounds is 0.0212 for 189 g of composition. The same type of calculation is carried out as for Example 1.

EXAMPLE 6: PREPARATION OF LOW-VISCOSITY POLYISOCYANATE COMPOSITION WITH MORE THAN ONE (B) COMPOUND AND TWO CATALYSTS

[0135] Two proteic polar reactive diluents, allophanate type, are synthesised using two mono-alcohols. Two types of catalyst are used. To synthesise the allophanate reactive diluents, a metallic salt of carboxylic acid is used, especially zinc bi-2-ethyl hexanoate (catalyst 1). To synthesise the biuret, an acid phosphate dialkyl is used (catalyst 2 or DBP). The quantities of reagents used are shown in Table 13

TABLE-US-00013 TABLE 13 Reagents 1- 2- Catalyst Catalyst HDI Water butanol propanol 1 2 Quantity in g 700 7.7 4.9 2.1 0.137 0.875

[0136] The molar ratios are shown in Table 14

TABLE-US-00014 TABLE 14 NCO/OH NCO/ Catalyst 1/ Catalyst 1/ DBP/ NCO/ alcohols water NCO OH alcohols NCO DBP 83 19.5 47.10.sup.?6 0.0039 0.0005 1984

[0137] The NCO titre of the reaction milieu at the end of the reaction is 0.957 mol for 100 g. After filtration, the quantity of reaction milieu sent for distillation is 676 g. The insoluble substance ratio is negligible. The quantity of polyisocyanate composition recovered following distillation of the excess diisocyanate monomer is 239 g; this produces a weighted output of 35.4%. The characteristics of the products obtained after distillation are shown in Table 15.

TABLE-US-00015 TABLE 15 NCO titre Viscosity Average molar HDI transformation % weight mPas 25? C. functionality, NCO rate, % (GPC) 22.6 1202 3 39

[0138] The distribution is shown in Table 16.

TABLE-US-00016 TABLE 16 Type of compound Compound of Example 6 composition % weight Monomer HDI 0.21 HDI mono carbamates 0.2 (d) HDI uretidine dione (HDI Dimer) 7.7 (b) Allophanates of HDI & n-butyl and of 12.7 HDI & isopropyl (n = 2) (a) Dimer-biuret, Biuret (n = 3, n = 5, n > 5) 72.2 (c) Biuret-allophanate polyisocyanate derivatives 7.6 of HDI and of (n-butyl and isopropyl)

[0139] In the case of Example 6, the molar fraction of allophanate functions of the (c) compounds is 0.025 mole per 239 g of composition. The same type of calculation is carried out as for Example 1.

EXAMPLE 7: PREPARATION OF LOW-VISCOSITY POLYISOCYANATE COMPOSITION WITH DIFFERENT CATALYST RATIO

[0140] The conditions of Example 6 are reproduced, but with a different Catalyst 1/NCO ratio. The quantities of reagents used are shown in Table 17.

TABLE-US-00017 TABLE 17 Reagent 1- 2- Catalyst Catalyst HDI Water butanol propanol 1 2 Quantity in g 500 5.5 3.5 1.5 0.052 0.625 Quantity in 2.976 0.306 0.047 0.0246 0.00015 0.003 mol

[0141] The molar ratios are shown in Table 18.

TABLE-US-00018 TABLE 18 NCO/OH NCO/ Catalyst 1/ Catalyst 1/ DBP/ NCO/ alcohols water NCO OH alcohols NCO DBP 83 19.5 25.10.sup.?6 0.0021 0.0005 1984

[0142] The NCO titre of the reaction milieu at the end of the reaction is 0.967 mol for 100 g. After filtration, the quantity of reaction milieu sent for distillation is 468 g. The insoluble substance ratio is negligible. The quantity of polyisocyanate composition recovered following distillation of the excess diisocyanate monomer is 163 g; this produces a weighted output of 34.8%. The characteristics of the products obtained after distillation are shown in Table 19.

TABLE-US-00019 TABLE 19 NCO titre Viscosity mPas Average molar HDI transformation % weight 25? C. functionality, NCO rate, % (GPC) 22.9 1328 3.15 36.6

[0143] The distribution of the compounds is shown in Table 20.

TABLE-US-00020 TABLE 20 Type of compound Compound of Example 7 composition % weight Monomer HDI 0.13 HDI mono-carbamates 0.1 (d) HDI uretidine dione (HDI Dimer) 9.1 (b) Allophanates of HDI & n-butyl and of 6.3 HDI & isopropyl (a) Dimer-biuret, Biuret (n = 3, n = 5, n > 5) 73.3 (c) Biuret-allophanate polyisocyanate derivatives 11.07 of HDI and of (n-butyl and isopropyl)

[0144] In the case of Example 7, the molar fraction of allophanate functions of the (c) compounds is 0.046 mole per 163 g of composition. The same type of calculation is carried out as for Example 1.

[0145] The RMN .sup.13C analysis with iron acetylacetonate present, performed using a Brucker AV 500 device, identifies and quantifies the constituent functions of the polyisocyanate composition. The molar distribution of the functions identified in the polyisocyanate composition is shown in Table 21.

TABLE-US-00021 TABLE 21 Function identified, expressed in mol Isocyanurate function 0.9 Dimer functions (uretedine dione) 5.2 Allophanates function 5.5 Biuret functions 19.8 Sum total of functions identified 31.4 Molar ratio, biuret/biuret + allophanates function 78.3 Theoretical molar ratio, biuret/biuret + allophanates 81.03 functions based on number of moles of water and alcohols introduced

[0146] It is noted that the ratio (biuret functions/biuret+allophanates functions) measured by RMN .sup.13C is very largely consistent with the theoretical ratio calculated on the basis of the initial compounds used in the procedure, as it reaches a level of 96.6%, thus demonstrating the efficiency of the procedure.

[0147] Notably, RMN .sup.13C reveals the presence of a small quantity of isocyanurate type functions (2.84% of all functions identified) which were not identified by the gel permeation analysis coupled with infra-red. This means that during the synthesis procedure, a small quantity of HDI isocyanurate compound was formed.

[0148] RMN analysis of phosphorus 31 in a CDCl.sub.3 milieu reveals an absence of catalyst acid phosphate dibutyl used during synthesis of the biuret, but reveals the presence of symmetrical and dissymmetrical pyrophosphate compounds, in a molar ratio respectively equal to 68/32. The presence of dissymmetrical pyrophosphates shows that during the reaction, partial hydrolysis of a butyl group of the acid phosphate dibutyl catalyst has occurred.

EXAMPLE 8: APPLICATIONS OF POLYISOCYANATE COMPOSITIONS WITH 100% DRY EXTRACT

[0149] A formulation of a mixture of part A, containing compounds with reactive functions, with the isocyanate functions included in the polyisocyanate compounds of a part B, is prepared. The quantities are shown in Table 22.

[0150] For part A, a polyol resin is used (Product: ALBODUR U 955) with 8.79% of hydroxyl functions. For part B, the polyisocyanates from examples 3, 4 and 5 according to the invention are used, as are control polyisocyanates that are known (used and defined products). Tolonate HDT LV-NCO title: 22.78%, viscosity 1,185 mPa.Math.s at 25? C., Tolonate HDB LV-NCO title: 23.37%, viscosity 2,062 mPa.Math.s at 25? C. and Tolonate HDT-NCO title: 21.4%, viscosity 2,526 mPa.Math.s at 25? C.). We are working with a NCO/OH function molar ratio of 1 and a quantity of 220 ppm of tin dibutyl-dilaurate (DBTL) as catalyst.

[0151] The products are weighed in a 250-ml beaker and then mixed using a propeller blade for 1 minute, at a speed of 300 rpm. The products are then degassed in a desiccator, under aspiration (10 bar) for about 5 minutes, until the foam disappears. The time taken for the foam to disappear is recorded. The results are shown in Table 22.

TABLE-US-00022 TABLE 22 Part A-ALBODUR 34 34 34 34 34 Resin U955-g Part B-isocyanate Example Example Example HDTLV HDT hardener-g 3 4 5 product product 32.54 32.26 32.69 32.43 34.52 Appearance after Foam gone Request foam foam removal (5 removal time > 5 min min)

[0152] It is observed that the low-viscosity biuret motif polyisocyanates according to the invention show a shorter removal time and therefore have a faster application time than the known products. This is a significant advantage, because of the very low viscosity of the invention polyisocyanates.

[0153] For a first series of Shore hardness assessments, the formulation is poured into an aluminium capsule 74 mm in diameter. The quantity poured averages 30 g, to produce the required minimum thickness of 6 mm.

[0154] For a second series of traction assessments, the formulation is poured onto a polyethylene plaque measuring 8 cm?12 cm. The quantity poured averages 27 g, to produce the required minimum thickness of 2 mm. All of the preparations are stored in an air-conditioned room at 23? C. and 50% RH and then analysed after 7 days of storage. The results are shown in Tables 24 (Shore D hardness) and 25 (appearance after traction).

TABLE-US-00023 TABLE 24 Shore D hardness Part B Day 1, t.sub.0 Day 1, t.sub.15 min Day 3 Day 7 Example 3 35/25 35/25 45/30 49/32 Example 4 36/26 36/26 44/29 47/31 HDTLV product 27/18 27/18 36/25 42/28 HDT product 36/25 36/25 36/26 42/29

[0155] The mechanical property results obtained using a traction machine are shown in Table 25.

TABLE-US-00024 TABLE 25 Polyisocyanate Module (MPa) Stress (MPa) Distortion (%) Example 3 6.34 8.72 157.58 Example 4 6.04 7.42 142.61 HDTLV product 6.94 5.14 97.71 HDT product 7.56 5.76 105.32

[0156] It is observed that the very low-viscosity biuret motif polyisocyanates according to the invention present better performance levels compared to the Tolonate HDT LV and Tolonate HDT products. It is also observed that the low-viscosity biuret motif polyisocyanates according to the invention show better compatibility with |ALBODUR resin compared to the Tolonate HDT LV and Tolonate HDT products.

EXAMPLE 9: APPLICATIONS OF POLYISOCYANATE COMPOSITIONS ACCORDING TO THE INVENTION AND OF FORMULATION REFERENCES WITH SOLVENT

[0157] Viscosity is measured using a Lamy RHEOMAT RM 300 rheometer. A sample of the product to be defined is placed in a tank. The stirring module is introduced and set going. The device shows the viscosity of the product at a given sheer level and a given temperature, for a period of one minute. The stirring module is chosen according to the target viscosity field. For the target compositions of the invention examples, the viscosity is given for a value at 25? C. and overall for a sheer gradient in the region of 100 s.sup.?1.

[0158] The titre in NCO functions is measured using acid-base measurement. The measurement is carried out using a Metrohm 916 titrator. A sample of polyisocyanate composition with a known mass is set in reaction, with stirring, with dibutylamine solution of known titre and quantity, at ambient temperature (20? C. approx). The quantity of dibutylamine is excessive in relation to the isocyanate functions. After 1 minute, the reaction milieu containing the excess dibutylamine is measured at ambient temperature (20? C. approx) using a HCl solution with known titre. The difference between dibutylamine introduced initially and dibutylamine measured corresponds to the quantity of dibutylamine that has reacted with the isocyanate functions. We therefore have access to the isocyanate function titre of the polyisocyanate function, expressed either as a weighted % of NCO functions or as a mole of NCO functions for 100 g of polyisocyanate composition.

[0159] The Shore hardness measurement (D) is taken using a Hildebrand hardness meter.

[0160] The mechanical properties are measured using a MTS traction machine. The samples are prepared by pouring about 27 g of formula containing the target polyisocyanate onto a polyethylene plate measuring 12 cm by 8 cm to produce a thickness of 2 mm. The crosslinking is carried out in an air-conditioned room at 23? C. and 50% relative humidity (RH) and measured after 7 days of storage. Cutting is then performed using a removal device for the parts inserted into the traction machine, in order to measure the mechanical properties of the parts. The breaking elongation is then measured and expressed as a %, this being the elongation length beyond which the material breaks, the stress on rupture being expressed in N/mm.sup.2 or MPa and being the force necessary to break a test sample measuring length?thickness. Generally speaking, the harder the material, the greater the stress on rupture.

[0161] The term pot-life defines the lifetime of a formula of 2 compounds (2K), which are a polyisocyanate hardener and a polyol or polyamine.

[0162] Persoz hardness allows paint layer hardness to be measured after cross-linking.

[0163] Impact resistance is measured using 2 Erichsen 304 marking devices according to Standards ISO 6272 dated 1993 and ASTM D 2794 dated 1984.

[0164] To measure folding resistance, an Erichsenconical chuck is used. The method allows the elasticity and adhesion forced of a paint film, subjected to bending, to be measured,

[0165] A formula is prepared, constituting a mixture of Part A containing compounds with reactive functions with the isocyanate functions contained in the polyisocyanates of a part B. The Part A used is a formulation of acrylic polyol in solvent and containing a mixture of two acrylic polyols (products: SETALUX 1907 BA 75 and Setal 1603 BA 78 X). Additives and a catalyst with tin dibutyl dilaurate base (DBTL) formulated to 1% weight are added to the n-butyl acetate (produced by Alfa Aesar). The products and quantities in Part A are shown in Table 26.

[0166] The two resins are weighed in a beaker and then stirred in a dispermat with a deflocculating blade, at a speed of 1500 rpm. During stirring, we add the products one by one, allowing 5 minutes for dispersion between each addition. When the additions are complete, Part A is left to be stirred for a further 20 minutes. We pour the formula into a closed glass flask and allow it to degas at atmospheric pressure for at least one night before using.

TABLE-US-00025 TABLE 26 % weight Acrylic polyol (product: Setalux 1907 BA-75) 70.06 Polyester polyol (product: Setal 1603 BA-78) 7.65 Solvent 1 methyl amyl ketone (product: MAK) 10.69 Solvent 2 (product: Solvesso 100) 4.37 Additive 1 (product: Tinuvin 1130-BASF) 1.36 Additive 2 (product: Tinuvin 292-BASF) 0.45 Levelling agent (products: BYK-315, 0.11, BYK-332 (10% in AcBu), BYK-358) 0.50, 0.30 Catalyst (DBTL 1% in acbu) 4.52

[0167] Part B consists of the polyisocyanate hardener. Invention polyisocyanates from examples 4 and 5 are used, together with reference polyisocyanate systems (products: Tolonate HDT, Tolonate HDB LV and Tolonate HDT LV from Vencorex).

[0168] Part C consists of a mixture of solvents for adjusting the viscosity (cutting) according to the proportions shown in Table 27. The two solvents are weighed in a glass flask and mixed for at least 30 minutes in the pot roller.

TABLE-US-00026 TABLE 27 Solvent for cutting % weight Methyl amyl ketone 47.87 N-butyl acetate 52.13

[0169] Next, the 2K varnish is prepared using a molar ratio of 1.1 for the NCO/OH functions. Parts A and B are weighed and then mixed manually using a spatula for 3-5 minutes, until a homogeneous mixture is obtained. The solvent part is added to the mixture, which is homogenised. The quantity of solvent to be added has been determined by DIN-4 cutting of about 24 seconds (readjustment of solvent according to DIN-4, 22-26 seconds). The products and proportions are shown in table 28.

TABLE-US-00027 TABLE 28 Isocyanate Example Example Tolonate Tolonate Tolonate hardener 4 5 HDTLV HDBLV HDT NCO titre (%) 22.9 22.6 22.8 23.38 21.6 Part A (% 100 100 100 100 100 weight) Part B (% by 32.12 32.54 32.26 31.46 34.05 weight) Part C (% by 21.57 22.33 22.25 22.30 22.87 weight) DIN 4 23.21 24.11 22 23.70 23.89 (seconds)

[0170] The film is applied according to the tests to be carried out, using a manual applicator or a gun. The films are then dried at ambient temperature (23? C.) at 50% relative humidity (RH) or baked for 30 minutes at 60? C. following a 10-minute flash-off. All the films are stored in an air-conditioned room at 23? C. and 50% RH.

[0171] The hardness, brilliance and chemical resistance levels are assessed for films applied to a glass plate using a film-drawer 200 ?m thick. Folding and QUV tests are carried out on films applied to an aluminium plate, the coverings consisting of an undercoat and base. The impact resistance and adherence tests have been performed on a steel plate, the coverings consisting of an undercoat and base.

TABLE-US-00028 TABLE 29 Persoz hardness after drying at 70? C. Time (days) Isocyanate hardener 1 3 8 Example 4 150 249 274 Example 5 155 258 280 Tolonate HDTLV 132 203 261 Tolonate HDT 132 241 273

[0172] The low-viscosity polyisocyanate hardeners according to the invention show a shorter network construction time than the reference polyisocyanates with an isocyanurate base (HDT and HDTLV) (Table 29).

[0173] The results shown in Table 30 are based on a number of ratings. The adherence rating ranges from 0 (excellent) to 5 (poor); the folding resistance rating ranges from 0 (excellent) to 5 (poor). The maximum AFNOR rating for impact resistance is 100. The maximum ASTM rating for impact resistance is 80. Impact resistance is better when the rating value is higher.

TABLE-US-00029 TABLE 30 Example Tolonate Isocyanate hardener 4 5 HDBLV HDT Adhesion 3 4 5 5 Folding resistance Confirmed Confirmed Confirmed Confirmed ASTM impact resistance 80 80 70 80 AFNOR impact resistance 100 100 90 100

[0174] The polyisocyanate hardener systems covered by the invention show a greater level of adherence and impact resistance than the HDT and HDBLV reference systems.

[0175] Overall, the hardeners according to the invention show a lower viscosity, with performances equivalent to and sometimes better than the reference isocyanate systems. A better adherence level and shock resistance level are noted.

EXAMPLE 10: PREPARATION OF VERY LOW-VISCOSITY POLYISOCYANATE COMPOSITION

[0176] In this test, zinc bi-neodecanoate is used as a single catalyst in synthesis of the (b) allophanate reactive diluent and the (a) biuret-type compounds.

[0177] The procedure is as for Example 1, with different quantities of reagents used as shown in Table 31. The blocker used is dibutyl phosphate.

TABLE-US-00030 TABLE 31 Di-butyl Zinc bi- phosphate Reagent HDI Water 1-butanol neodecanoate acid Quantity in g 600 5 4.26 0.15 0.15

[0178] The molar ratios are shown in Table 32.

TABLE-US-00031 TABLE 32 NCO/OH NCO/ Metal/OH alcohol water Metal/NCO alcohol 124 25.7 52 10.sup.?6 0.0064

[0179] The NCO titre of the reaction mass prior to distillation is 1.023 mol for 100 g of reaction milieu. 574 g of reaction mass is filtered to eliminate 0.2 g of solid impurities. The filtrate is then distilled in a vacuum at 140? C. to eliminate the excess HDI monomer. 150 g of polyisocyanate composition is obtained. The weighted output recovered is 26%. The characteristics of the example 10 products obtained following distillation of the excess diisocyanate monomer used are shown in Table 33. The average NCO molar function is calculated on the basis of the composition analysed by gel permeation chromatography (GPC-IR).

TABLE-US-00032 TABLE 33 NCO Viscosity Average molar HDI titre % mPas functionality, transformation weight 25? C. NCO rate, % weight 23.2 686 2.8 26

[0180] The distribution of the compounds is shown in Table 34.

TABLE-US-00033 TABLE 34 Type of % compound Compound of Example 10 composition weight Monomer HDI 0.28 (d) HDI uretidine dione (HDI Dimer) 11.2 (b) HDI and n-butyl allophanate 14.2 (a) Dimer-biuret, Biuret (n = 3, n = 5, 69.3 n > 5) (c) HDI and n-butyl biuret-allophanate 5 polyisocyanate derivatives

[0181] In the case of example 10, the molar fraction of allophanate functions of the (c) compounds is 0.0056 for 150 g of composition.

EXAMPLE 11: PREPARATION OF LOW-VISCOSITY POLYISOCYANATE COMPOSITION

[0182] In this test, zinc bi-neodecanoate is used as a single catalyst in synthesis of the (b) allophanate reactive diluent and the (a) biuret-type compounds.

[0183] The procedure is as for Example 1, with different quantities of reagents used as shown in Table 35.

TABLE-US-00034 TABLE 35 Dibutyl 1- Zinc bi- phosphate Reagent HDI Water butanol neodecanoate acid Quantity in g 600 7.5 4.69 0.15 0.15

[0184] The molar ratios are shown in Table 36.

TABLE-US-00035 TABLE 36 NCO/OH NCO/ Metal/OH alcohol water Metal/NCO alcohol 113 17.2 52 10.sup.?6 0.0058

[0185] The NCO titre of the reaction mass prior to distillation is 0.893 mol for 100 g of reaction milieu. 562.5 g of reaction mass is filtered to eliminate 0.16 g of solid impurities. The filtrate is then distilled in a vacuum at 140? C. to eliminate the excess HDI monomer. 247 g of polyisocyanate composition is obtained. The weighted output recovered is 44%.

[0186] The characteristics of the example 11 products obtained following distillation of the excess diisocyanate monomer used are shown in Table 37. The average NCO molar function is calculated on the basis of the composition analysed by gel permeation chromatography (GPC-IR).

TABLE-US-00036 TABLE 37 NCO Viscosity Average molar HDI titre % mPas functionality, transformation weight 25? C. NCO rate, % weight 21.6 3157 3.2 47

[0187] The distribution of the compounds is shown in Table 38.

TABLE-US-00037 TABLE 38 Type of compound Compound of Example 11 composition % weight Monomer HDI 0.4 (d) HDI uretidine dione (HDI Dimer) 4.5 (b) HDI and n-butyl allophanate 9.4 (a) Dimer-biuret, Biuret (n = 3, n = 5, 78.9 n > 5) (c) HDI and n-butyl biuret-allophanate 6.4 polyisocyanate derivatives

[0188] The (a) compounds represent about 79% weight of the composition of example 11. In the case of example 11, the molar fraction of allophanate functions of the (c) compounds is 0.0017 for 247 g of composition.

EXAMPLE 12: VISCOSITY OF (B) COMPOUNDS

[0189] After synthesis of various (b) compounds, the characteristics of these compounds were then measured and are shown in Table 39. Viscosity was measured using the Rheomat 300 Module 114.

TABLE-US-00038 TABLE 39 Monomer Viscosity Nature of HDI content, NCO titre mPas at alcohol % weight % weight 25? C. Butan-1-ol 0.05 18.6 98 Propan-2-ol 0.1 20 124 (IPA) Butan-2-ol 0.5 19.4 124.7 Cyclohexanol 0.05 17.6 406

EXAMPLE 13: PREPARATION OF AVERAGE-VISCOSITY POLYISOCYANATE COMPOSITION

[0190] The procedure is as for example 2, but with different quantities of reagents used, as shown in Table 40.

TABLE-US-00039 TABLE 40 Reagent HDI Water 1-butanol bNZ Quantity in g 600 14 9 0.15

[0191] The molar ratios are shown in Table 41.

TABLE-US-00040 TABLE 41 NCO/OH NCO/ bNZ/OH bNZ/OH alcohol water bNZ/NCO alcohol totals 59.5 9.2 52.10.sup.?6 0.0031 4.1 10.sup.?4

[0192] The quantity of blocking agent, di-butyl phosphate, corresponds to twice the molar quantity of catalyst.

[0193] The quantity of polyisocyanate recovered following reaction and distillation of the diisocyanate monomer is 249.5 g, corresponding to a recovered weighted output of 55.9%. The reaction mass involved in distillation is 466 g. The NCO titre of the reaction milieu before distillation is 0.778 mol for 100 g.

[0194] The characteristics of the products obtained after distillation of the excess diisocyanate used are shown in Table 42.

TABLE-US-00041 TABLE 42 Average HDI NCO Viscosity molar transformation titre % mPas functionality, rate, weight 25? C. NCO % weight 19.7 21077 > 4 63.9

EXAMPLE 14: PREPARATION OF AVERAGE-VISCOSITY POLYISOCYANATE COMPOSITION

[0195] The procedure is as for example 2, but with different quantities of reagents used, as shown in Table 43.

TABLE-US-00042 TABLE 43 Reagent HDI Water 1-butanol bNZ Quantity in g 600 10.7 5.9 0.15

[0196] The molar ratios are shown in Table 44.

TABLE-US-00043 TABLE 44 NCO/OH NCO/ bNZ/OH bNZ/OH alcohol water bNZ/NCO alcohol totals 89.5 12 52.10.sup.?6 0.0046 5,5.10.sup.?4

[0197] The quantity of blocking agent, di-butyl phosphate, corresponds to three times the molar quantity of catalyst.

[0198] The quantity of polyisocyanate recovered following reaction and distillation of the diisocyanate monomer is 249.5 g, corresponding to a recovered weighted output of 55.9%. The reaction mass involved in distillation is 504 g. The NCO titre of the reaction milieu before distillation is 0.848 mol for 100 g.

[0199] The characteristics of the products obtained after distillation of excess diisocyanate monomer used are shown in the table. The average NCO molar function is calculated on the basis of the composition analysed by gel permeation chromatography (GPC-IR).

TABLE-US-00044 TABLE 45 NCO Viscosity HDI titre % mPas transformation weight 25? C. rate, % weight 19.7 21077 53

[0200] The distribution of the compounds is shown in Table 46.

TABLE-US-00045 TABLE 46 The molar Type of % compound Compound of Example 2 composition weight Monomer HDI 0.13 (d) HDI uretidine dione (HDI Dimer) 3.7 (b) HDI and n-butyl allophanate 5.1 (a) + (c) Dimer-biuret, Biuret (n = 3, n = 5, n > 5) 91.07 (c) HDI and n-butyl biuret-allophanate 20 polyisocyanate derivatives

[0201] fraction of the allophanate functions of the (c) compounds is 0.049 mole for 249.5 g of composition. The same type of calculation is carried out as for Example 1.