MULTIFUNCTIONAL ACRYLIC OLIGOMERS OF BRANCHED STRUCTURE, BY POLYADDITION BETWEEN MULTIFUNCTIONAL AMINES AND ACRYLATES

Abstract

The invention relates to an acrylated oligomer, having a number-average acrylate functionality f.sub.o>2, of branched structure resulting from the polyaddition reaction of at least one amine A) having a functionality f.sub.A of NH groups of at least 2, to at least one multifunctional acrylate B) having a functionality f.sub.B of acrylate groups of at least 2, with an average functionality per mole of all of the components A)+B) of greater than 2 and with said oligomer comprising in its repeating unit structure at least one O.sub.2CCH.sub.2CH.sub.2N=aminoacrylate group resulting from said polyaddition and with a content of nitrogen resulting from said amine A) of greater than or equal to 0.35 mEq/g and an initial ratio r=acrylate/NH of between nut and 1.1 r.sub.sup with n.sub.inf=0.90*(f.sub.A1)*(f.sub.B1) and r.sub.sup=2*f.sub.A+2*f.sub.B6 and the average number n.sub.av of repeating units per oligomer n.sub.av=1/[(r*f.sub.A/f.sub.B)+1f.sub.A].

The invention also relates to a specific preparation process and to the use of said oligomer in crosslinkable compositions, in particular as UV synergist in crosslinkable coatings, such as inks, varnishes, paints, adhesives and gel coats or in molding compositions or in compositions for 3D articles made by superposition of successive layers and finally to the crosslinked product that results therefrom.

Claims

1. An acrylated oligomer, wherein the oligomer has a number-average acrylate functionality f.sub.o of strictly greater than 2 acrylates per mole, has a branched structure and results from the polyaddition reaction of at least one amine A) having a functionality f.sub.A of NH groups of at least 2, with said NH functionality meaning a number-average functionality if it is a mixture of amines, said amine A) bearing primary and/or secondary amine functions, with optionally said amine A) bearing at least one tertiary amine function (without NH) and at least one multifunctional acrylate B) having a functionality f.sub.B of acrylate groups of at least 2, with said acrylate functionality meaning a number-average functionality if it is a mixture of acrylates, with a number-average functionality per mole of all of the components A) and B) of greater than 2 and with said oligomer comprising in its repeating unit structure at least one O.sub.2CCH.sub.2CH.sub.2N aminoacrylate group resulting from said polyaddition and with a content of nitrogen t.sub.A, resulting from said amine A), of greater than or equal to 0.35 mEq/g and an initial ratio r=acrylate/NH of between not and 1.1 r.sub.sup with the values r.sub.inf and r.sub.sup being defined according to equations (1) and (2) below:
r.sub.inf=0.90*(f.sub.A1)*(f.sub.B1) (1)
r.sub.sup=2*f.sub.A+2*f.sub.B6 (2) and with an average number n.sub.ay of repeating units per oligomer defined according to equation (3) below:
n.sub.av=1/[(r*f.sub.A/f.sub.B)+1f.sub.A](3).

2. The oligomer as of claim 1, wherein said amine A) bears in addition, at least one tertiary amine function and is selected from: dimethylaminopropylamine (DMAPA), dimethylaminopropylaminopropylamine (DMAPAPA) and 1,4-bis(3-aminopropyl)piperazine (1,4-BAPP) and with a content of nitrogen to resulting from the amine of greater than or equal to 0.35 mEq/g.

3. The oligomer of claim 1, wherein the viscosity of said acrylate B) measured according to the ISO 2555 method at 23 C. is less than 200 mPa.Math.s under a shear rate of 100 s.sup.1.

4. The oligomer of claim 1, wherein said acrylate B) is selected from the group consisting of: b1) optionally alkoxylated aliphatic or cycloaliphatic polyol acrylates, b2) oligoether acrylates, b3) alkoxylated phenolic acrylates and b4) acrylated aminoacrylates and mixtures thereof.

5. The oligomer of claim 1, wherein said amine A) is selected from the group consisting of: a1) an aliphatic amine, a2) a cycloaliphatic amine and a3) an aralkylene amine with the amine function at a position other than the alpha or beta position of the aromatic ring, and mixtures thereof.

6. The oligomer of claim 1, wherein said functionalities f.sub.A and f.sub.B are selected so that the sum f.sub.A+f.sub.B does not exceed 8.

7. The oligomer of claim 1, wherein the oligomer has a content of acrylate groups t.sub.acr of greater than 2.3 mmol/g or milliequivalents/g.

8. The oligomer of claim 1, wherein the oligomer has a number-average molecular mass Mn defined according to equation (4) below, ranging from 275 to 5000:
M.sub.n=M.sub.B+(n.sub.av*M.sub.u) (4) with M.sub.u being the molar mass of the repeating unit defined according to equation (5) below:
M.sub.u=M.sub.A+(f.sub.A2+2*f.sub.A11)*M.sub.B (5) n.sub.av being the average number of repeating units as defined in claim 1, M.sub.B being the molar mass of the acrylate B), M.sub.A being the molar mass of the amine A), f.sub.A1 being the number of primary amine NH.sub.2 functions, per amine A) and f.sub.A2 being the number of secondary amine NH functions, per amine A).

9. The oligomer of claim 1, wherein the oligomer has a content of nitrogen t.sub.A resulting from the amine expressed in mEq/g ranging from 0.4 to 5 with t.sub.A being defined according to equation (6) below:
t.sub.A=1000*n.sub.av*(f.sub.A1+f.sub.A2+f.sub.A3)/M.sub.n (6) with M.sub.n being the number-average molecular mass as defined above and f.sub.A1 being the number of primary amine NH.sub.2 functions, per amine A) and f.sub.A2 being the number of secondary amine NH functions, per amine A) and f.sub.A3 being the number of tertiary amine N functions, per amine A).

10. (canceled)

11. The oligomer of claim 1, wherein said amine A) has a functionality f.sub.A greater than or equal to 2 and that said acrylate B) has a functionality f.sub.B greater than or equal to 3 or conversely said amine A) has a functionality f.sub.A greater than or equal to 3 and that said acrylate B) has a functionality f.sub.B greater than or equal to 2.

12. The oligomer of claim 1, wherein: said amine A) is of general formula (NH.sub.2).sub.fA1R2(NHR3).sub.fA2, with R2=R(NRR).sub.fA3, R3, R, R and R being identical or different C.sub.1 to C.sub.3 alkyls with f.sub.A1 being equal to 0 and being the number of primary amine functions per mole, f.sub.A2 being greater than or equal to 2 and being the number of secondary amine functions per mole and f.sub.A3 being greater than or equal to 0 and being the number of tertiary amine functions per mole and with f.sub.A=f.sub.A2 said acrylate B) is of general formula R1(X).sub.fB with X being a CH.sub.2CHCO.sub.2 acrylate group and R1 being the residue of said acrylate B) bearing f.sub.B acrylates per mole said oligomer comprises the product of the general formula (I) below:
X.sub.(fB-1)R1[O.sub.2CCH.sub.2CH.sub.2NR3R2Y.sub.(fA2-2)NR3CH.sub.2CH.sub.2CO.sub.2R1X.sub.(fB-2)].sub.nX (I) with Y=(NR3CH.sub.2CH.sub.2COOR1X.sub.(fB-1)).

13. The oligomer of claim 1, wherein: said amine A) is of general formula (NH.sub.2).sub.fA1R2(NHR3).sub.fA2, with R2=R(NRR).sub.fA3, R3, R, R and R being identical or different C.sub.1 to C.sub.3 alkyls, f.sub.A1 being greater than or equal to 1 and being the number of primary amine functions per mole, f.sub.A2 being greater than or equal to 0 and being the number of secondary amine functions per mole and f.sub.A3 being greater than or equal to 0 and being the number of tertiary amine functions per mole and with
f.sub.A=2*f.sub.A1+f.sub.A2 said acrylate B) is of general formula R1(X).sub.fB with X being a CH.sub.2CHCO.sub.2 acrylate group and R1 being the residue of said acrylate B) bearing f.sub.B acrylates per mole, said oligomer comprises the product of general formula (II) below:
X.sub.(fB-1)R1[O.sub.2CCH.sub.2CH.sub.2NR2Y.sub.fA2Z.sub.(fA1-1)CH.sub.2CH.sub.2CO.sub.2R1X.sub.(fB-2)].sub.nX (II) with Y=(NR3CH.sub.2CH.sub.2CO.sub.2R1X.sub.(fB-1) and Z=(N(CH.sub.2CH.sub.2COOR1X.sub.(fB-1)).sub.2).

14. The oligomer of claim 11, wherein said functionality f.sub.A is equal to 3 and said amine A) is selected from a diamine bearing a primary amine function and a secondary amine function or a triamine bearing 3 secondary amine functions.

15. The oligomer of claim 11, wherein said amine A) has a functionality f.sub.A equal to 2 and is a primary amine or a diamine bearing 2 secondary amine functions and that said acrylate B) is an optionally alkoxylated triacrylate with, in the case where said triacrylate is alkoxylated, a number of alkoxy units per acrylate that does not exceed 3 if said alkoxy is ethoxy and a number of alkoxy units per acrylate that does not exceed 1 if said alkoxy is propoxy.

16. The oligomer of claim 11, wherein said amine A) has a functionality f.sub.A equal to 3, which is a primary-secondary diamine or a triamine bearing 3 secondary amine functions and said acrylate B) is an optionally alkoxylated diacrylate with, in the case where said diacrylate is alkoxylated, a number of alkoxy units per acrylate that does not exceed 2 if said alkoxy is ethoxy and a number of alkoxy units per acrylate that does not exceed 1 if said alkoxy is propoxy.

17. The oligomer of claim 11, wherein said functionality f.sub.A is equal to 4 and said amine A) is selected from a diamine bearing 2 primary amine functions or a triamine bearing 1 primary amine function and 2 secondary amine functions or a tetra-amine bearing 4 secondary amine functions.

18. The oligomer of claim 11, wherein said functionality f.sub.A is equal to 5 and said amine A) is selected from a triamine bearing two primary amine functions and one secondary amine function or a tetra-amine bearing one primary amine function and three secondary amine functions or a penta-amine bearing 5 secondary amine functions.

19. The oligomer of claim 11, wherein said functionality f.sub.A is equal to 6 and said amine A) is selected from a triamine bearing three primary amine functions or a tetra-amine bearing 2 primary amine functions and 2 secondary amine functions or a penta-amine bearing 1 primary amine function and 4 secondary amine functions or a hexa-amine bearing 6 secondary amine functions.

20. (canceled)

21. The oligomer of claim 1, wherein the oligomer results from the reaction between at least two amines A) and/or at least two acrylates B).

22. The oligomer of claim 1, wherein it comprises n repeating units with a molecular distribution as a function of n comprising at least the 4 products corresponding to: n=0 and n=1 and n=2 and n=3 and with at least 50% by weight of said distribution corresponding to n less than or equal to 3.

23. (canceled)

24. A process for preparing an oligomer as defined in claim 1, comprising a step of Michael polyaddition reaction of said at least one amine A) to said at least one acrylate B), in the presence of a radical polymerization inhibitor and in the absence of any solvent, of any catalyst and of any other reactant except for said amine A) and said acrylate B) and said inhibitor, said process comprising the gradual and continuous addition of said amine A) to said acrylate B) already present in the reactor and always in stoichiometric excess and with said reaction taking place at a temperature above 40 C. and below 90 C., and with said reaction being stopped at a degree of conversion of the NH amine functions of at least 95% and with an initial ratio r of acrylate functions to NH amine functions, r=acrylate/NH being between r.sub.inf and 1.1 r.sub.sup with the values r.sub.inf and r.sub.sup being defined according to equations (1) and (2) below:
r.sub.inf=0.90*(f.sub.A1)*(f.sub.B1) (1)
r.sub.sup=2*f.sub.A+2*f.sub.B6 (2)

25. A crosslinkable composition comprising at least one oligomer as defined claim 1, with optionally the presence of a reactive diluent.

26. The composition of claim 25, wherein the composition is a radiation-crosslinkable composition which is a coating composition, or is a composition for 3D articles made by superposition of successive layers or is a molding composition.

27. The composition of claim 25, wherein the composition is a peroxide-crosslinkable composition which is a coating composition, or is a chemical sealing composition or is a molding composition.

28.-30. (canceled)

31. A crosslinked final product, wherein the product is obtained by the process as of claim 24.

Description

EXAMPLES OF PREPARATION OF THE DIMMERS ACCORDING TO THE INVENTION

Example A-1

[0083] Introduced into a 1-litre reactor equipped with an anchor agitator and surmounted by a simple ascending condenser, device enabling the venting of the reaction medium, and air inlet (air sparging), a dropping funnel and a temperature probe are: 178.4 g of hexanediol diacrylate (HDDA) (0.7895 mol) and 84.7 mg of hydroquinone methyl ether (EMHQ).

[0084] Next, gradually introduced into the reactor via the dropping funnel over one hour are: 33.5 g of dimethylaminopropylaminopropylamine (DMAPAPA) (0.2105 mol) during which the reaction mixture is gradually brought to 80 C. and maintained at this temperature until a conversion of greater than 95% of the primary and secondary (1+2) reactive amine functions and stabilisation of the viscosity, i.e. 10 hours of reaction. After cooling to ambient temperature, a product having a clear, light yellow appearance is obtained.

Example A2

[0085] Carried out in an identical manner with respect to Example A1, except by replacing, at equal weight for A), the HDDA with 178.4 g of 3-methyl-1,5-pentanediol diacrylate (3M1,5PDDA) (0.7895 mol). A product having a clear, light yellow appearance is obtained.

Example A3

[0086] Carried out in an identical manner with respect to Example A1, except that the acrylate B) and amine A) reactants are modified as follows: for B), 188.49 g of dipropyleneglycol diacrylate (DPGDA) (0.7895 mol) and for A), 35.15 g of dimethylamino-propylaminopropylamine (DMAPAPA) (0.2105 mol), A product having a clear, light yellow appearance is obtained.

[0087] The molar compositions and characteristics of the 3 oligomers obtained A1, A2 and A3 are presented below in Table 2.

TABLE-US-00002 TABLE 2 Molar compositions and characteristics of the oligomers A1, A2 and A3 Oligomer reference per example A1 A2 A3 Reactive component (moles) A): 3M1,5PDDA 0.7895 B): DPGDA 0.7895 B): HDDA 0.7895 A): DMAPAPA 0.2105 0.2105 0.2105 Characteristics r 2.50 2.50 2.35 t.sub.A (mEq/g) 2.94 2.94 2.69 Viscosity at 25 C. (mPa .Math. s) 255 250 590 t.sub.acr (mEq/g) 4.47 4.47 4.08 f.sub.o (mEq/mol) 2.57 2.57 2.57 n.sub.av 0.57 0.57 0.57 M.sub.n calc 575 575 631

Example B1

[0088] Carried out in an identical manner with respect to Example A1, except that the acrylate B) and amine A) reactants are modified as follows: for B), 303.45 g of trimethylolpropane (4 ethoxy) triacrylate (TMP4EOTA) (0.6429 mol) and for A), 36.42 g of dimethylaminopropylamine (DMAPA) (0.3571 mol). A product having a clear, light yellow appearance is obtained.

Example B2

[0089] Carried out in an identical manner with respect to Example A1, except that the acrylate B) and amine A) reactants are modified as follows: for B), 197.34 g of trimethylolpropane triacrylate (TMPTA) (0.6667 mol) and for A), 34.00 g of dimethylaminopropylamine (DMAPA) (0.3333 mol). A product having a clear, light yellow appearance is obtained.

[0090] The table below groups together the molar compositions of the reactants A) and B) and the characteristics of the oligomers B1 and B2 as described above.

TABLE-US-00003 TABLE 3 Molar composition of the reactants A) and B) and characteristics of the oligomers B1 and B2 Oligomer reference B1 B2 Reactive component (moles) B): TMP4EOTA 0.6429 B): TMPTA 0.6667 A): DMAPA 0.3571 0.3333 Characteristics r 2.70 3.00 t.sub.A (mEq/g) 2.32 2.88 Viscosity at 25 C. (mPa .Math. s) 2000 6400 t.sub.acr (mEq/g) 3.57 5.76 f.sub.o (mEq/mol) 4.25 4.00 n.sub.av 1.25 1.00 M.sub.n calc 1190 694

Example C1

[0091] Carried out in an identical manner with respect to Example A1, except that the acrylate B) and amine A) reactants are modified as follows: for B), 193.71 g of hexanediol diacrylate (HDDA) (0.8571 mol) and for A), 28.58 g of 1,4-bis(3-aminopropyl)piperazine (1,4BAPP) (0.1429 mol). A product having a clear, light yellow appearance is obtained.

[0092] The molar composition of the reactants A) and B) and characteristics of the oligomers D1 and D2 are presented in Table 5 below.

Example C2

[0093] Carried out in an identical manner with respect to Example A1, except that the acrylate B) and amine A) reactants are modified as follows: for B), 193,71 g of hexanediol diacrylate (HDDA) (0.8571 mol) and for A), 20.29 g of 1,3-bis(aminomethyl)cyclohexane (1,3BAC) (0.1429 mol). A product having a clear, light yellow appearance is obtained.

[0094] The molar composition of the reactants A) and B) and characteristics of the oligomers C1 and C2 are presented in Table 4 below.

TABLE-US-00004 TABLE 4 Molar composition of the reactants A) and B) and characteristics of the oligomers C1 and C2 Oligomer reference C1 C2 Reactive component (moles) B): HDDA 0.8571 0.8571 A): 1,3BAC 0.1429 A): 1,4BAPP 0.1429 Characteristics r 3.00 3.00 t.sub.A (mEq/g) 2.57 1.34 Viscosity at 25 C. (mPa .Math. s) 955 340 t.sub.acr (mEq/g) 5.14 5.34 f.sub.o (mEq/mol) 2.67 2.67 n.sub.av 0.33 0.33 M.sub.n calc 519 499

Example D1

[0095] Carried out in an identical manner with respect to Example A1, except that the acrylate B) and amine A) reactants are modified as follows: for B), 380.45 g of trimethylolpropane (3 ethoxy) triacrylate (TMP3EOTA) (0.8889 mol) and for A), 22.22 g of 1,4-bis(3-aminopropyl)piperazine (1,4BAPP) (0.1111 mol). A product having a clear, light yellow appearance is obtained.

Example D2

[0096] Carried out in an identical manner with respect to Example A1, except that the acrylate B) and amine A) reactants are modified as follows: for B), 380.49 g of trimethylolpropane (3 ethoxy) triacrylate (TMP3EOTA) (0.8889 mol) and for A), 15.78 g of 1,3-bis(aminomethyl)cyclohexane (1,3BAC) (0.1111 mol). A product having a clear, light yellow appearance is obtained.

[0097] The molar composition of the reactants A) and B) and characteristics of the oligomers D1 and D2 are presented in Table 5 below.

TABLE-US-00005 TABLE 5 Molar composition and characteristics of the oligomers D1 and D2 Oligomer reference D1 D2 Reactive component (moles) TMP3EOTA 0.8889 0.8889 1,3BAC 0.1111 1,4BAPP 0.1111 Characteristics r 6.00 6.00 t.sub.A (mEq/g) 1.10 0.56 Viscosity at 25 C. (mPa .Math. s) 1740 1278 t.sub.acr (mEq/g) 5.52 5.61 f.sub.o (mEq/mol) 4.00 4.00 n.sub.av 0.20 0.20 M.sub.n calc 725 713

[0098] The oligomers prepared according to the examples described above were tested in crosslinkable formulations (application compositions) as described below.

Formulations and Preparation

[0099] The oligomers are formulated by mixing at ambient temperature according to the following compositions F1 to F18 with two types of formulations tested.

Odd Formulae (F1, F3, F5, . . . F17)

[0100] Acrylate oligomer (A1 to D2): 96% by weight [0101] Darocure 1173: 4% by weight

Even Formulae (F2, F4, F6, . . . F18)

[0102] Acrylate oligomer (A1 to D2): 96% by weight [0103] Darocuree 1173: 2% by weight [0104] Benzophenone: 2% by weight

[0105] The compositions of the formulations produced F1 to F18 and their performances are presented in Tables 6 to 9 below, The methods of characterizing said oligomers and of determining the performances of said formulations F1 to F18 and the conditions used are mentioned below after these Tables 6 to 9.

TABLE-US-00006 TABLE 6 Formulations F1 to F6 based on oligomers A1 to A3 Formulation reference F1 F2 F3 F4 F5 F6 Components A1 96.0 96.0 A2 96.0 96.0 A3 96.0 96.0 Darocure 1173 4.0 2.0 4.0 2.0 4.0 2.0 Benzophenone 2.0 2.0 2.0 Performances Crosslinking 25 55 20 55 25 60 speed (mm/min) Persoz hardness 91 139 84 114 59 75 Pencil hardness H H HB HB B HB (5B-5H) Flexibility (mm) 3 3 3 3 4 3 Solvent 300 300 300 300 54 126 resistance (s)

TABLE-US-00007 TABLE 7 Formulations F7 to F10 based on oligomers B1 and B2 Formulation reference F7 F8 F9 F10 Components B1 96.0 96.0 B2 96.0 96.0 Darocure 1173 4.0 2.0 4.0 2.0 Benzophenone 2.0 2.0 Performances Crosslinking 40 65 100 speed (mm/min) Persoz hardness 96 157 97 Pencil hardness HB HB 4B (5B-5H) Flexibility (mm) 4 4 20 Solvent 300 300 300 resistance (s)

TABLE-US-00008 TABLE 8 Formulations F11 to F14 based on oligomers C1 and C2 Formulation reference F11 F12 F13 F14 Components C1 96.0 96.0 C2 96.0 96.0 Darocure 1173 4.0 2.0 4.0 2.0 Benzophenone 2.0 2.0 Performances Crosslinking 35 65 30 45 speed (mm/min) Persoz hardness 94 93 113 91 Pencil hardness 2H H HB HB (5B-5H) Flexibility (mm) 6 4 8 6 Solvent 300 300 300 300 resistance (s)

TABLE-US-00009 TABLE 9 Formulations F15 to F18 based on oligomers D1 and D2 Formulation reference F15 F16 F17 F18 Components D1 96.6 96.0 D2 96.0 96.0 Darocure 1173 4.0 2.0 4.0 2.0 Benzophenone 2.0 2.0 Performances Crosslinking 35 55 25 40 speed (mm/min) Persoz hardness 160 124 186 170 Pencil hardness 3H B HB HB (5B-5H) Flexibility (mm) 15 10 20 15 Solvent 300 300 300 300 resistance (s)

Methods of Determining the Characteristics of the Oligomers the Performance of the Formulations

1) Appearance

[0106] The product is observed visually in daylight through a 60 ml colorless glass flask and it is distinguished whether the product is: [0107] clear: no turbidity, it is comparable to water, [0108] hazy: no longer enabling clear vision through the flask, [0109] cloudy: opaque flask, no image can be seen through the flask.
2) Viscosity acoording to Noury viscosity

[0110] The time of travel, in the liquid to be characterized, of a steel ball subjected to its own gravity is measured. The AFNOR XP.T51-213 standard specifies in particular the geometry of the container, the diameter of the ball (2 mm) and the course of the ball (104 mm). Under these conditions, the dynamic viscosity is proportional to the travel time of the ball with: 1 second corresponding to 0.1 Pa.Math.s.

3) Content of Amine t.SUB.A.: Calculation According to Equation (6) Defined Above in the Description

[0111] 4) Functionality f.sub.o: Calculation According to Equation (7) Define above in the Description
5) Content of Acrylate t.sub.acr: Calculation According to Equation (8) Defined above in the Description
6) Reactivity through Crosslinking Speed

[0112] The formulations F1 to F18 are applied as a 12 m film to a contrast card (Leneta Penoparc charts form 1B), then crosslinked using a 120 W/cm Hg Fusion UV lamp. The minimum run speed needed (in m/min) to obtain a film that is dry to the touch is measured. The higher the speed, the more reactive the formulation.

[0113] For the hardness, flexibility and acetone resistance tests, the photocrosslinked films are left in an air-conditioned room at 23 C. for 24 hours after crosslinking and before the measurements.

7) Persoz Hardness

[0114] The formulation to be examined is applied as a 100 m film to a glass plate and crosslinked using a 120 W/cm Hg Fusion UV lamp at a speed of 8 m/min.

[0115] The result is given as the number of oscillations before damping of the oscillations (passing from an amplitude of 12 to 4), of a pendulum in contact with the coated glass plate, according to the ISO 1522 standard.

8) Flexibility

[0116] The formulation examined is applied as a 100 m film to a smooth steel plate having a thickness of 25/10 mm (D-46 Q-Panel), then crosslinked using a 120 W/cm Hg Fusion UV lamp at a speed of 8 m/min.

[0117] The coated plate is bent round cylindrical mandrels, according to the ISO 1519 standard. The result is expressed by the value (in mm) of the smallest radius of curvature that can be imposed on the coating without it cracking or detaching from the support.

9) Acetone Resistance (Chemical Resistance)

[0118] The formulation examined is applied as a 12 m film to a glass plate, then crosslinked using a 120 W/cm Hg Fusion UV lamp at a speed of 8 m/min. The coating is rubbed with a cloth soaked in acetone. The result used corresponds to the time (expressed in seconds) beyond which the film detaches and/or disintegrates.

10) Number-Average Molecular Mass Mn: Calculation According to Equation (4) Defined above in the Description