POLYPROPYLENE BASED HOT-MELT ADHESIVE COMPOSITION

Abstract

The invention relates to an adhesive composition wherein such composition comprises at least one polypropylene copolymer and wherein such adhesive composition has improved overall bond performance. It further relates to an article comprising said adhesive composition, as well as to a process for producing such article. It even further relates to the use of the adhesive composition in the preparation of an article.

Claims

1. An adhesive composition comprising at least one polypropylene copolymer, wherein such polypropylene copolymer has: a) at least one comonomer selected from the group consisting of ethylene and C.sub.4-C.sub.12 alpha-olefin, b) a total comonomer content in the range of 4.5 to 20.0 wt %, c) Vicat A temperature >80 C., as measured according to ISO 306, d) storage modulus (G23) in the range of 100 to 1000 MPa as measured at 23 C. according to ISO 6721-02 and ISO 6721-07, e) melting temperature in the range of 120 to 160 C. as measured according to ISO 11357-3 and at least one of: a polymer other than the at least one polypropylene copolymer, a tackifying resin, a plasticizer, an additive or a filler.

2. The adhesive composition according to claim 1 wherein the polypropylene copolymer has a tensile modulus (E) in the range of 200 to 1000 MPa as measured according to ISO 527 1 at 23 C.

3. The adhesive composition according to claim 1 wherein the polypropylene copolymer is a polypropylene copolymer-1 (PC-1) having at least one comonomer selected from the group consisting of ethylene, a C.sub.4-C.sub.12 alpha-olefin, and a combination thereof and wherein such polypropylene copolymer-1 (PC-1) has a Flexibility >0.8 which is calculated according to the equation:
Flexibility=EAY*100000/(TSY*E) wherein: EAY is the elongation at yield value, TSY is the tensile strength at yield value, in MPa and E is the tensile modulus value, in MPa.

4. The adhesive composition according to claim 3 wherein the polypropylene copolymer-1 (PC-1) has: a) a glass transition temperature T.sub.g1 in the range of 12 to 2 C. and b) a glass transition temperature T.sub.g2 in the range of 65 to 20 C.

5. The adhesive composition according to claim 3 wherein the polypropylene copolymer-1 (PC-1) has: a) storage modulus (G23) in the range of 150 to 450 MPa as measured at 23 C. according to ISO 6721-02 and ISO 6721-07 and b) melting temperature in the range of 135 to 155 C. as measured according to ISO 11357-3,

6. The adhesive composition according to claim 1 wherein the polypropylene copolymer is a polypropylene copolymer-2 (PC-2) comprising units derived from propylene, ethylene and at least one comonomer selected from linear or branched C.sub.4-C.sub.12 alpha-olefin and wherein such polypropylene copolymer-2 (PC-2) has: a) a glass transition temperature Tg in the range of 12 to 0 C. and b) a total comonomer content in the range of 6.0 to 15.0 wt %.

7. The adhesive composition according to claim 6 wherein the polypropylene copolymer-2 (PC-2) has: a) storage modulus (G23) in the range of 300 to 600 MPa as measured at 23 C. according to ISO 6721-02 and ISO 6721-07 and b) melting temperature in the range of 125 to 135 C. as measured according to ISO 11357-3.

8. The adhesive composition according to claim 6 wherein the polypropylene copolymer-2 (PC-2) has a tensile modulus (E) in the range of 500 to 1000 MPa as measured according to ISO 527-1 at 23 C.

9. The adhesive composition according to claim 6 wherein the comonomers in the polypropylene copolymer-2 (PC-2) are ethylene and C.sub.4 alpha-olefin.

10. The adhesive composition according to claim 1 wherein the at least one polymer other than the at least one polypropylene copolymer has a) melting temperature <120 C. as measured according to ISO 11357-3, b) storage modulus (G23) <50 MPa as measured at 23 C. according to ISO 6721-02 and ISO 6721-07, c) density <0.96 g/cm.sup.3 as measured according to ISO 1183D and d) an MFR.sub.2 in the range of 0.20 to 2000 g/10 min as measured according to ISO 1133.

11. The adhesive composition according to claim 1 wherein the adhesive composition has: a) at least one polymer other than the at least one polypropylene copolymer present in the range of 0.01 to 50.0 wt %, the percentage of the at least one polymer other than the at least one polypropylene copolymer is calculated based on the total amount of polypropylene copolymer and of at least one polymer other than the at least one polypropylene copolymer comprised in the adhesive composition and b) Flexibility >0.5 and which is calculated according to the equation:
Flexibility=EAY*100000/(TSY*E) wherein: EAY is the elongation at yield value, TSY is the tensile strength at yield value, in MPa and E is the tensile modulus value, in MPa.

12. An article comprising an adhesive composition and at least one substrate, wherein the adhesive composition comprises at least one polypropylene copolymer, wherein such polypropylene copolymer has: a) at least one comonomer selected from the group consisting of ethylene and C.sub.4-C.sub.12 alpha-olefin, b) a total comonomer content in the range of 4.5 to 20.0 wt %, c) Vicat A temperature >80 C., as measured according to ISO 306, d) storage modulus (G23) in the range of 100 to 1000 MPa as measured at 23 C. according to ISO 6721-02 and ISO 6721-07, e) melting temperature in the range of 120 to 160 C. as measured according to ISO 11357-3; and at least one of: a polymer other than the at least one polypropylene copolymer, a tackifying resin, a plasticizer, an additive, or a filler.

13. A process to produce an article wherein the process comprises at least the step of applying at least one adhesive composition on at least one surface of at least one substrate wherein the adhesive composition comprises at least one polypropylene copolymer, wherein such polypropylene copolymer has: a) at least one comonomer selected from the group consisting of ethylene and C.sub.4-C.sub.12 alpha-olefin, b) a total comonomer content in the range of 4.5 to 20.0 wt %, c) Vicat A temperature >80 C., as measured according to ISO 306, d) storage modulus (G23) in the range of 100 to 1000 MPa as measured at 23 C. according to ISO 6721-02 and ISO 6721-07, e) melting temperature in the range of 120 to 160 C. as measured according to ISO 11357-3; and at least one of: a polymer other than the at least one polypropylene copolymer, a tackifying resin, a plasticizer, an additive, or a filler.

14. A method comprising preparing an article according to claim 12 with an adhesive composition, wherein the adhesive composition comprises at least one polypropylene copolymer, wherein such polypropylene copolymer has: a) at least one comonomer selected from the group consisting of ethylene and C.sub.4-C.sub.12 alpha-olefin, b) a total comonomer content in the range of 4.5 to 20.0 wt %, c) Vicat A temperature >80 C., as measured according to ISO 306, d) storage modulus (G23) in the range of 100 to 1000 MPa as measured at 23 C. according to ISO 6721-02 and ISO 6721-07, e) melting temperature in the range of 120 to 160 C. as measured according to ISO 11357-3; and at least one of: a polymer other than the at least one polypropylene copolymer, a tackifying resin, a plasticizer, an additive, or a filler.

15. A process to prepare an adhesive composition according to claim 1 comprising combining at least one polypropylene copolymer with at least one of: a polymer other than the at least one polypropylene copolymer, a tackifying resin, a plasticizer, an additive or a filler.

16. The adhesive composition according to claim 2 wherein the polypropylene copolymer is a polypropylene copolymer-1 (PC-1) having at least one comonomer selected from the group consisting of ethylene, a C.sub.4-C.sub.12 alpha-olefin, and a combination thereof and wherein such polypropylene copolymer-1 (PC-1) has a Flexibility >0.8 which is calculated according to the equation:
Flexibility=EAY*100000/(TSY*E) wherein: EAY is the elongation at yield value, TSY is the tensile strength at yield value, in MPa and E is the tensile modulus value, in MPa.

17. The adhesive composition according to claim 16 wherein the polypropylene copolymer-1 (PC-1) has: a) a glass transition temperature T.sub.g1 in the range of 12 to 2 C. and b) a glass transition temperature T.sub.g2 in the range of 65 to 20 C.

18. The adhesive composition according to claim 4 wherein the polypropylene copolymer-1 (PC-1) has: a) storage modulus (G23) in the range of 150 to 450 MPa as measured at 23 C. according to ISO 6721-02 and ISO 6721-07 and b) melting temperature in the range of 135 to 155 C. as measured according to ISO 11357-3.

19. The adhesive composition according to claim 2 wherein the polypropylene copolymer is a polypropylene copolymer-2 (PC-2) comprising units derived from propylene, ethylene and at least one comonomer selected from linear or branched C.sub.4-C.sub.12 alpha-olefin and wherein such polypropylene copolymer-2 (PC-2) has: a) a glass transition temperature Tg in the range of 12 to 0 C. and b) a total comonomer content in the range of 6.0 to 15.0 wt %.

20. The adhesive composition according to claim 7 wherein the polypropylene copolymer-2 (PC-2) has a tensile modulus (E) in the range of 500 to 1000 MPa as measured according to ISO 527-1 at 23 C.

Description

EXAMPLES

IMEASURING METHODS

[0127] The following definitions of terms and determination methods apply for the above general description of the invention as well as to the below examples unless otherwise defined.

a) VicatA temperature Measurement

[0128] The Vicat-A temperature is determined according to ISO 306 (A50) using injection moulded test specimens having the following dimensions: 80104 mm The injection moulded test specimens are prepared as described in EN ISO 1873-2.

b) Melt Flow Rate

[0129] The melt flow rate (MFR.sub.2) is determined according to ISO 1133 and is indicated in g/10 min. The MFR2 is an indication of the flowability and hence the processability of the polymer. The higher the melt flow rate, the lower the viscosity of the polymer. The MFR2 of polypropylene is determined at a temperature of 230 C. and under a load of 2.16 kg. The MFR.sub.2 of polyethylene, of polyolefin based plastomer (POP) and of elastomer (POE) is determined at a temperature of 190 C. and under a load of 2.16 kg.

c) DSC Analysis

[0130] The melting temperature (T.sub.m) and the crystallisation temperature (TO were measured with a TA Instrument Q2000 differential scanning calorimetry device (DSC) according to ISO 11357/3 on 5 to 10 mg samples. Crystallisation (TO and melting temperatures (T.sub.m) were obtained in a heat/cool/heat cycle with a scan rate of 10 C./min between 30 C. and 225 C. Melting (T.sub.m) and crystallisation (TO temperatures were taken as the peaks of the endotherms and exotherms in the cooling cycle and the second heating cycle respectively.

d) Xylene Cold Soluble (XCS)

[0131] The content of xylene cold soluble (XCS) is determined at 25 C. according to ISO 16152; fifth edition; 2005-07-01. The part which remains insoluble is the xylene cold insoluble (XCI) fraction.

e) Intrinsic Viscosity (IV)

[0132] The intrinsic viscosity (IV) is measured according to ISO 1628/1, in decalin at 135 C. The intrinsic viscosity (IV) value increases with the molecular weight of a polymer.

f) Density

[0133] The density is measured according to ISO 1183D. The samples preparation is carried out by compression moulding according to ISO 1872-2:2007.

g) Dynamic Mechanical Thermal Analysis (DMTA)

[0134] The storage modulus G and the glass transition temperature T.sub.g were measured by DMTA analysis. The DMTA evaluation and the storage modulus G measurements were carried out in torsion mode on compression moulded samples at temperature between -130 C. and +150 C. using a heating rate of 2 C./min and a frequency of 1 Hz, according to ISO 6721-02 and ISO 6721-07. The measurements were carried out using an Anton Paar MCR 301 equipment. The compressed moulded samples have the following dimensions: 40101 mm and are prepared in accordance to ISO 1872-2:2007. The storage modulus G23 and G70 were measured at 23 C. and 70 C. respectively.

[0135] h) Tensile properties

[0136] The tensile properties, the elongation at break (EAB), elongation at yield (EAY), tensile strength at break (TSB) and tensile strength at yield (TSY) were measured at 23 C. according to ISO 527-1:2012/ ISO 527-2:2012 on injection moulded specimens, type 1B, prepared according to ISO 527-2:2012 and using an extensometer (Method B) produced according to ISO 1873-2 with 4 mm sample thickness. The test speed was 50 mm/min, except for the tensile modulus (E) measurement which was carried out at a test speed of 1 mm/min.

i) Comonomer Content

[0137] Quantitative nuclear-magnetic resonance (NMR) spectroscopy was used to quantify the comonomer content of the polymers.

Comonomer Content Quantification of Poly(propylene-co-ethylene) Copolymers

[0138] Quantitative .sup.13C {.sup.1H} NMR spectra were recorded in the solution-state using a Bruker Advance III 400 NMR spectrometer operating at 400.15 and 100.62 MHz for .sup.1H and .sup.13C respectively. All spectra were recorded using a .sup.13C optimised 10 mm extended temperature probe head at 125 C. using nitrogen gas for all pneumatics. Approximately 200 mg of material was dissolved in 3 ml of1,2-tetrachloroethane-d.sub.2 (TCE-d2) along with chromium-(III)-acetylacetonate (Cr(acac).sub.3) resulting in a 65 mM solution of relaxation agent in solvent {8}. To ensure a homogenous solution, after initial sample preparation in a heat block, the NMR tube was further heated in a rotatory oven for at least 1 hour. Upon insertion into the magnet the tube was spun at 10 Hz. This setup was chosen primarily for the high resolution and quantitatively needed for accurate ethylene content quantification. Standard single-pulse excitation was employed without NOE, using an optimised tip angle, 1 s recycle delay and a bi-level WALTZ16 decoupling scheme {3, 4}. A total of 6144 (6k) transients were acquired per spectra.

[0139] Quantitative .sup.13C {.sup.1H} NMR spectra were processed, integrated and relevant quantitative properties determined from the integrals using proprietary computer programs. All chemical shifts were indirectly referenced to the central methylene group of the ethylene block (EEE) at 30.00 ppm using the chemical shift of the solvent. This approach allowed comparable referencing even when this structural unit was not present. Characteristic signals corresponding to the incorporation of ethylene were observed {7}.

[0140] The comonomer fraction was quantified using the method of Wang et. al. {6} through integration of multiple signals across the whole spectral region in the .sup.13C {.sup.1H} spectra. This method was chosen for its robust nature and ability to account for the presence of regio-defects when needed. Integral regions were slightly adjusted to increase applicability across the whole range of encountered comonomer contents.

[0141] For systems where only isolated ethylene in PPEPP sequences was observed the method of Wang et al. was modified to reduce the influence of non-zero integrals of sites that are known to not be present. This approach reduced the overestimation of ethylene content for such systems and was achieved by reduction of the number of sites used to determine the absolute ethylene content to:

E=0.5 (S+S+S+0.5(S+S))

[0142] Through the use of this set of sites the corresponding integral equation becomes:

E=0.5 (I.sub.H+I.sub.G+0.5(I.sub.C+I.sub.D))

using the same notation used in the article of Wang et al. {6}. Equations used for absolute propylene content were not modified.

[0143] The mole percent comonomer incorporation was calculated from the mole fraction:

E[mol %]=100*fE

[0144] The weight percent comonomer incorporation was calculated from the mole fraction:

E[wt %]=100*(fE*28.06)/((fE*28.06)+((1fE)*42.08))

BIBLIOGRAPHIC REFERENCES

[0145] 1Busico, V., Cipullo, R., Prog. Polym. Sci. 26 (2001) 443. [0146] 2Busico, V., Cipullo, R., Monaco, G., Vacatello, M., Segre, A. L., Macromoleucles 30 (1997) 6251. [0147] 3Zhou, Z., Kuemmerle, R., Qiu, X., Redwine, D., Cong, R., Taha, A., Baugh, D. Winniford, B., J. Mag. Reson. 187 (2007) 225. [0148] 4Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun. 2007, 28, 1128. [0149] 5Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253. [0150] 6Wang, W-J., Zhu, S., Macromolecules 33 (2000), 1157. [0151] 7Cheng, H. N., Macromolecules 17 (1984), 1950. [0152] 8Singh, G., Kothari, A., Gupta, V., Polymer Testing 28 5 (2009), 475. [0153] 9Kakugo, M., Naito, Y., Mizunuma, K., Miyatake, T. Macromolecules 15 (1982) 1150. [0154] 10Randall, J. Macromol. Sci., Rev. Macromol. Chem. Phys. 1989, C29, 201.
Comonomer content poly(propylene-co-ethylene-co-butene)

[0155] Quantitative .sup.13C {.sup.1H} NMR spectra recorded in the molten-state using a Bruker Advance III 500 NMR spectrometer operating at 500.13 and 125.76 MHz for .sup.1H and .sup.13C respectively. All spectra were recorded using a .sup.13C optimised 7 mm magic-angle spinning (MAS) probe head at 180 C. using nitrogen gas for all pneumatics. Approximately 200 mg of material was packed into a 7 mm outer diameter zirconia MAS rotor and spun at 4.5 kHz. This setup was chosen primarily for the high sensitivity needed for rapid identification and accurate quantification{1, 2, 6} Standard single-pulse excitation was employed utilising the NOE at short recycle delays {3, 1} and the RS-HEPT decoupling scheme {4, 5}. A total of 1024 (1k) transients were acquired per spectra.

[0156] Quantitative .sup.13C {.sup.1H} NMR spectra were processed, integrated and relevant quantitative properties determined from the integrals. All chemical shifts are internally referenced to the methyl isotactic pentad (mmmm) at 21.85 ppm. Characteristic signals corresponding to regio defects were not observed {11}. The amount of propene was quantified based on the main S methylene sites at 44.1 ppm:

Ptotal=I.sub.S

[0157] Characteristic signals corresponding to the incorporation of 1-butene were observed and the comonomer content quantified in the following way. The amount isolated 1-butene incorporated in PPBPP sequences was quantified using the integral of the B2 sites at 44.1 ppm accounting for the number of reporting sites per comonomer:

B=I.sub.B2/2

[0158] The amount consecutively incorporated 1-butene in PPBBPP sequences was quantified using the integral of the B2 site at 40.5 ppm accounting for the number of reporting sites per comonomer:

BB=2*.sub.B2

[0159] The total 1-butene content was calculated based on the sum of isolated and consecutively incorporated 1-butene:

Btotal=B+BB

[0160] The total mole fraction of 1-butene in the polymer was then calculated as:

fB=(Btotal/(Etotal+Ptotal+Btotal)

[0161] Characteristic signals corresponding to the incorporation of ethylene were observed and the comonomer content quantified in the following way. The amount isolated ethylene incorporated in PPEPP sequences was quantified using the integral of the Say sites at 37.9 ppm accounting for the number of reporting sites per comonomer:

E=I.sub.S/2

[0162] With no sites indicative of consecutive incorporation observed the total ethylene comonomer content was calculated solely on this quantity:

Etotal=E

[0163] The total mole fraction of ethylene in the polymer was then calculated as:

fE=(Etotal/(Etotal+Ptotal+Btotal)

[0164] The mole percent comonomer incorporation was calculated from the mole fractions:

B[mol %]=100*fB

E[mol %]=100*fE

[0165] The weight percent comonomer incorporation was calculated from the mole fractions:

B [wt %]=100*(fB*56.11)/((fE*28.05)+(fB*56.11)+((1(fE+fB))*42.08))

E [wt %]=100*(fE*28.05)/((fE*28.05)+(fB*56.11)+((1(fE+fB))*42.08))

BIBLIOGRAPHIC REFERENCES

[0166] 1Klimke, K., Parkinson, M., Piel, C., Kaminsky, W., Spiess, H. W., Wilhelm, M., Macromol. Chem. Phys. 2006; 207:382. [0167] 2Parkinson, M., Klimke, K., Spiess, H. W., Wilhelm, M., Macromol. Chem. Phys. 2007; 208:2128. [0168] 3Pollard, M., Klimke, K., Graf, R., Spiess, H. W., Wilhelm, M., Sperber, O., Piel, C., Kaminsky, W., Macromolecules 2004; 37:813. [0169] 4Filip, X., Tripon, C., Filip, C., J. Mag. Resn. 2005, 176, 239. [0170] 5Griffin, J. M., Tripon, C., Samoson, A., Filip, C., and Brown, S. P., Mag. Res. in Chem. 2007 45, S1, S198. [0171] 6Castignolles, P., Graf, R., Parkinson, M., Wilhelm, M., Gaborieau, M., Polymer 50 (2009) 2373. [0172] 7Busico, V., Cipullo, R., Prog. Polym. Sci. 26 (2001) 443. [0173] 8Busico, V., Cipullo, R., Monaco, G., Vacatello, M., Segre, A. L., Macromoleucles 30 (1997) 6251. [0174] 9Zhou, Z., Kuemmerle, R., Qiu, X., Redwine, D., Cong, R., Taha, A., Baugh, D. Winniford, B., J. Mag. Reson. 187 (2007) 225. [0175] 10Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun. 2007, 28, 1128. [0176] 11Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253.

j) Flexibility

[0177] The Flexibility value is calculated according to the equation below:

Flexibility=EAY*100000/(TSY*E)

wherein: [0178] EAY is the elongation at yield value, [0179] TSY is the tensile strength at yield value, in MPa and [0180] E is the tensile modulus value, in MPa.

IIINVENTIVE AND COMPARATIVE EXAMPLES

a) Inventive Examples

[0181] IE-1, IE-2, IE-3, IE-4 and IE-7 are polypropylene copolymers.

[0182] IE-5 is a polypropylene copolymer prepared by vis-breaking IE-2 in an extruder in the presence of peroxides.

[0183] IE-6 is a polypropylene copolymer prepared by vis-breaking IE-4 in an extruder in the presence of peroxides.

[0184] IE-8 and IE-9 are polypropylene copolymers prepared by vis-breaking IE-7 in an extruder in the presence of peroxides.

b) Comparative Examples

[0185] CE-1 is a polypropylene homopolymer with MFR.sub.2 of 5 g/10 min and is manufactured and distributed by Borealis.

[0186] CE-2 is a polypropylene homopolymer with MFR.sub.2 of 125 g/10 min and is manufactured and distributed by Borealis.

[0187] CE-3 is a polypropylene ethylene copolymer with MFR.sub.2 of 8 g/10 min and melting point of 144 C., and is manufactured and distributed by Borealis.

[0188] CE-4 is a high flow polypropylene ethylene copolymer with MFR.sub.2 of 28 g/10 min and is manufactured and distributed by Borealis.

[0189] CE-5 is polypropylene impact copolymer with MFR.sub.2 of 13 g/10 min and is manufactured and distributed by Borealis.

[0190] CE-6 is a polypropylene homopolymer with MFR.sub.2 of 450 g/10 min and is manufactured and distributed by Borealis.

[0191] CE-7 is a high flow polypropylene ethylene copolymer with MFR.sub.2 of 110 g/10 min and is manufactured and distributed by Borealis.

[0192] CE-8 is a polypropylene ethylene copolymer with MFR.sub.2 of 8 g/10 min and melting point of 140 C. and is manufactured and distributed by Borealis.

[0193] All comparative examples are produced using a Ziegler-Natta based catalyst system.

c) Preparation of Inventive Polypropylene Copolymers IE-1, IE-2, IE-3, IE-4 and IE-7

[0194] The polymerisation process for the preparation of the Inventive Examples according to the invention was carried in a Borstar pilot plant having a pre-polymeriser, a 1.sup.st loop reactor, a 1.sup.st gas phase reactor (GPR1) and a 2.sup.nd gas phase reactor (GPR2) all reactors being arranged in series. Such a process was carried out in the presence of either catalyst-1 or catalyst-2, depending of the case, in combination with triethylaluminium (TEAL) as co-catalyst and di-cyclopentyldimethoxy silane as external donor (donor D). The polymerisation conditions for the preparation of the Inventive examples as well as the type of catalyst are summarized in Table 1.

Catalyst-1

[0195] Catalyst-1 is prepared using an emulsion process. Such a process for the preparation of catalyst-1 is described in WO2010009827, example section, page 30 to 31.

Catalyst-2

[0196] Catalyst-2 is prepared by the following method: [0197] a) First, 0.1 mol of MgCl.sub.23 mol EtOH were suspended under inert conditions in 250 ml of decane in a reactor at atmospheric pressure. [0198] b) The solution was cooled to 15 C., then 300 ml of cold TiCl.sub.4 were added while maintaining the temperature at said temperature. [0199] c) The temperature of the slurry was increased slowly to 20 C. At this temperature 0.02 mol of dioctylphthalate (DOP) was added to the slurry. [0200] d) After the addition of the dioctylphthalate (DOP), the temperature was raised to 135 C. during 90 minutes and the slurry was allowed to stand for 60 minutes. [0201] e) Then 300 ml of TiCl were added by keeping the temperature at 135 C. for 120 minutes. [0202] f) The catalyst was then filtered and washed six times with 300 ml of heptane at 80 C. [0203] g) Once the solid catalyst has been recovered, it was filtered and dried.

[0204] More details related to catalyst-2 preparation are described in EP491566, EP591224 and EP586390.

d) Preparation of Vis-Broken Polypropylene Copolymers IE-5, IE-6, IE-8 and IE-9

[0205] The vis-broken polypropylene copolymer was prepared by mixing a specific amount of polypropylene copolymer with a specific amount of peroxide Trigonox 101 in a co-rotating twin screw extruder type Coperion ZSK 40 having a screw diameter of 40 mm, and a L/D ratio of 38. The vis-broken polypropylene preparations were carried out at temperatures in the range of 170-190 C. and using a high intensity mixing screw configuration with two sets of kneading blocks. The vis-breaking length is defined as the ratio between the desired target MFR.sub.2 and the initial MFR2.

[0206] For the preparation of IE-5, IE-6, IE-8 and IE-9 the following amounts of peroxide were respectively used 50 ppm, 325 ppm, 860 ppm, 2000 ppm.

e) Preparation of Hot-Melt Adhesive Composition Containing Polyethylene Wax, Inventive (IE-13, IE-14, IE-15, IE-16 and IE-17) and Comparative Examples (CE-9, CE-10 and CE-11)

[0207] All the compositions have been prepared by mixing a specific amount of polypropylene copolymer with a specific amount of polyethylene wax in a co-rotating twin screw extruder type Coperion ZSK 40 having a screw diameter of 40 mm, and a L/D ratio of 38. The composition preparations were carried out at temperatures in the range of 170-190 C. and using a high intensity mixing screw configuration with two sets of kneading blocks. The percentages of polypropylene copolymer and polyethylene wax used in the preparation of the hot-melt adhesive compositions are mentioned in Table 4. The compositions included in the formulation 500 ppm of Irganox 1010 (Pentaerythrityl-tetrakis(3-(3,5-di-tert. Butyl-4-hydroxyphenyl)-propionate), 500 ppm of Irgafos 168 (Tris (2,4-di-t-butylphenyl) phosphite) and 400 ppm of calcium stearate as additives. The polyethylene wax used in the preparation of the hot-melt adhesive compositions shown in Table 4 is a high molecular weight and high density polyethylene wax manufactured and distributed by Clariant under the name of Licowax PE 190 powder.

f) Preparation of Hot-Melt Adhesive Composition Containing Ethylene Based Plastomer (IE-10 and IE-12)

[0208] All the compositions have been prepared by mixing a specific amount of polypropylene copolymer with a specific amount of ethylene based plastomer in a co-rotating twin screw extruder type Coperion ZSK 40 having a screw diameter of 40 mm, and a L/D ratio of 38. The composition preparations were carried out at temperatures in the range of 170-190 C. and using a high intensity mixing screw configuration with two sets of kneading blocks. The percentages of polypropylene copolymer and ethylene based plastomer used in the preparation of the hot-melt adhesive compositions are mentioned in Table 5. The compositions also included in the formulation 500 ppm of Irganox 1010 (Pentaerythrityl-tetrakis (3- (3,5-di-tert. Butyl-4-hydroxyphenyl)-propionate), 500 ppm of Irgafos 168 (Tris (2,4-di-t-butylphenyl) phosphite) and 400 ppm of calcium stearate as additives. The ethylene based plastomer used in the preparation of the hot-melt adhesive compositions shown in Table 5 is an ethylene based octene plastomer sold under the name of Queo 8230, which is manufactured and distributed by Borealis Plastomers (NL).

g) Preparation of Hot-Melt Adhesive Composition Containing Ethylene-Acrylate Copolymer (IE-11)

[0209] All the compositions have been prepared by mixing a specific amount of polypropylene copolymer with a specific amount of ethylene-acrylate copolymer in a co-rotating twin screw extruder type Coperion ZSK 40 having a screw diameter of 40 mm, and a L/D ratio of 38. The composition preparations were carried out at temperatures in the range of 170-190 C. and using a high intensity mixing screw configuration with two sets of kneading blocks. The percentages of polypropylene copolymer and ethylene-acrylate copolymer used in the preparation of the hot-melt adhesive compositions are mentioned in Table 5. The compositions also included in the formulation 500 ppm of Irganox 1010 (Pentaerythrityl-tetrakis(3-(3,5-di-tert. Butyl-4-hydroxyphenyl)- propionate), 500 ppm of Irgafos 168 (Tris (2,4-di-t-butylphenyl) phosphite) and 400 ppm of calcium stearate as additives. The ethylene-acrylate copolymer used in the preparation of the hot-melt adhesive compositions shown in Table 5 is a copolymer of ethylene and methyl acrylate sold under the name of Elvaloy AC 1330 manufactured and distributed by DuPont.

[0210] From Table 2 it can be derived that the polypropylene copolymers-1 (inventive examples) show a higher Flexibility level and better elasticity level compared to the comparative examples. The elasticity level is determined by the storage modulus (G23). Additionally, the thermal resistance, measured as Vicat-A and G23/G70, of the inventive examples keep a good level. Therefore the great advantage of the polypropylene copolymers-1 (inventive examples) over the comparative examples is that they present a good balance of improved elasticity level, Flexibility level and high heat resistance.

[0211] From Table 3 it can be derived that the polypropylene copolymers-2 (inventive examples) show higher Flexibility level and better elasticity level (G23) compared to the comparative examples. Additionally, the thermal resistance of the inventive examples can be kept at a good level even if the melting temperature (T.sub.m) is lower, in relation to the comparative examples.

[0212] From Table 4 it can be derived that the inventive adhesive compositions present a proper combination of heat resistance, flexibility and elasticity (G23) compared to the comparative examples.

[0213] From Table 5 it can be derived that the presence of the ethylene based elastomer and of the ethylene-acrylate copolymer, respectively, improves the Flexibility and the elasticity (G23) levels in the adhesive compositions keeping a good level of thermal resistance (Vicat-A). Thus a proper combination of heat resistance, flexibility and elasticity is obtained and as result an adhesive composition with improved overall bond performance.

TABLE-US-00001 TABLE 1 Polymerization conditions for Inventive Examples. Unit IE-1 IE-2 IE-3 IE-4 IE-7 Pre- Catalyst Catalyst-1 Catalyst-2 Catalyst-1 Catalyst-1 Catalyst-2 polymerisation Temperature C. 28 28 28 28 28 TEAL/Ti mol/mol 98 110 100 100 120 TEAL/Donor wt %/wt % 4 4 4 4 3 Residence time min 20 20 20 20 20 Donor D D D D D Loop Temperature C. 70 70 70 70 67 H2/C3 mol/kmol 0.6 5.0 2.9 6.0 5.8 C2/C3 mol/kmol 26.0 17.2 23.8 23.8 21.3 Butene feed Kg/h 0 0 0 0 40 Split % 32 30 33 33 100 MFR g/10 min 0.7 6 3.9 8 7.4 XCS wt % 5.2 3 5.5 5.3 4.6 Residence time h 0.90 0.78 0.89 0.83 0.48 C2 content wt % 2.5 2.0 2.5 2.5 1.1 GPR1 Temperature C. 80 75 80 80 H2/C3 mol/kmol 9.0 19.6 36.0 71.6 C2/C3 mol/kmol 38.0 62.6 34.0 36.9 Split % 48 45 50 49 MFR g/10 min 0.7 1.7 3.9 8.0 XCS wt % 7.9 22 8.3 7.8 Residence time h 1.7 2 2.8 2.9 C2 content wt % 3.9 6.5 4.2 4.1 GPR2 Temperature C. 70 70 70 70 H2/C3 mol/kmol 113 138 537 532 C2/C3 mol/kmol 679 408 535 541 Split % 20 25 17 18 MFR g/10 min 0.7 1.5 3.9 7 XCS wt % 24 43 20 20 Residence time h 1.1 0.7 1.3 1.4 C2 content wt % 8.5 15 8.2 8.5

TABLE-US-00002 TABLE 2 Polypropylene copolymers-1 properties (inventive and comparative examples)*. Unit IE-1 IE-2 IE-3 IE-4 IE-5 IE-6 CE-1 CE-2 CE-3 CE-4 CE-5 MFR.sub.2 g/10 min 1.0 1.5 3.7 7.0 3.8 29.0 5.0 125 8.0 28.0 13.0 Visbreaking 1.0 1.0 1.0 1.0 2.5 4.1 1.5 1.0 length Total comonomer wt % 8.0 15.0 8.2 8.0 15.0 8.0 0.0 0.0 3.5 3.6 8.3 XCS wt % 22.0 44.0 20.0 20.0 44.0 19.2 3.0 2.2 8.0 6.1 18.0 IV XCS dl/g 2.4 2.4 1.7 1.7 1.9 1.5 n.m. n.m. n.m. n.m. 2.4 C.sub.2 XCS wt % 29.0 31.0 29.0 29.0 30.0 29.0 n.m. n.m. n.m. n.m. 42.0 T.sub.m C. 140 150 142 140 150 142 162 162 144 150 164 Tg matrix C. 4.1 7.0 4.0 6.1 7.0 6.0 2.0 0.0 3.8 3.8 1.3 Tg rubbber C. 54.0 46.0 50.0 50.0 47.0 54.0 n.m. n.m. n.m. n.m. 59.0 G23 C. MPa 304 224 336 325 218 379 1051 991 533 562 627 G70 C. MPa 91 62 96 89 57 112 486 416 170 172 265 G70/G23 C. 0.3 0.3 0.3 0.3 0.3 0.3 0.5 0.4 0.3 0.3 0.4 Vicat-A C. 117 94 119 118 94 117 150 148 127 125 150 Tensile modulus, MPa 600 342 647 618 331 592 1611 1810 961 1123 1216 E Tensile strength at MPa 25.0 16.0 22.0 23.0 17.0 22.0 35.0 38.2 29.0 29.0 26.0 break, TSB Tensile strength at MPa 19.0 12.0 19.0 19.0 11.0 20.0 35.0 34.0 26.0 29.0 26.0 yield, TSY Elongation at % 440 532 430 492 521 520 408 11 507 175 57 break, EAB Elongation at % 15.0 21.0 13.0 13.0 20.0 14.0 8.8 7.5 12.0 12.0 7.0 yield, EAY Flexibility 1.32 5.12 1.06 1.11 5.49 1.18 0.16 0.12 0.48 0.37 0.22 *n.m. = not measured

TABLE-US-00003 TABLE 3 Polypropylene copolymers-2 properties (inventive and comparative examples)*. Unit IE-7 IE-8 IE-9 CE-1 CE-2 CE-3 CE-4 CE-6 CE-7 MFR.sub.2 at 230 C., 2.16 kg g/10 min 6.0 96.0 310 5.0 125 8.0 28.0 450 110 Visbreaking length 1.0 16.0 51.7 1.5 1.0 5.0 2.6 C.sub.2 matrix wt % 1.0 0.0 3.5 C.sub.2 total wt % 1.0 1.0 1.0 0.0 0.0 3.5 3.6 0.0 3.5 C.sub.4 9.0 9.0 9.0 XCS wt % 5.3 5.6 5.4 3.0 2.2 8.0 6.1 2.8 7.6 IV XCS dl/g n.m. n.m. n.m. n.m. n.m. n.m. n.m. n.m. n.m. C.sub.2 XCS wt % n.m. n.m. n.m. n.m. n.m. n.m. n.m. n.m. n.m. T.sub.m C. 131 132 131 162 162 144 150 161 151 Tg matrix C. 3.0 2.0 2.0 2.0 0.0 3.8 3.8 0.1 3.6 Tg rubber C. n.m. n.m. n.m. n.m. n.m. n.m. n.m. n.m. n.m. G23 C. MPa 496 485 470 1051 991 533 562 n.m. 597 G70 C. MPa 138 130 125 486 416 170 172 n.m. 174 G70/G23 C. 0.28 0.27 0.27 0.46 0.42 0.32 0.31 n.m. 0.29 Vicat-A C. 117 115 114 150 148 127 125 152 126 Tensile modulus, E MPa 778 803 786 1611 1810 961 1123 1503 1193 Tensile strength at break, TSB MPa 23.0 24.0 23.0 35.0 38.2 29.0 29.0 26.7 30.3 Tensile strength at yield, TSY MPa 23.0 24.0 23.0 35.0 34.0 26.0 29.0 26.7 30.3 Elongation at break, EAB % 450 354 206 408 11 507 175 3.2 168 Elongation at yield, EAY % 11.0 12.0 11.0 8.8 7.5 12.0 12.0 3.2 11.0 Flexibility 0.61 0.62 0.61 0.16 0.12 0.48 0.37 0.08 0.30 *n.m. = not measured

TABLE-US-00004 TABLE 4 Properties of adhesive compositions containing a polyethylene wax*. Unit IE-13 IE-14 IE-15 IE-16 IE-17 CE-9 CE-10 CE-11 IE-3 wt % 95.0 90.0 85.0 75.0 60.0 CE-8 wt % 75.0 CE-1 wt % 95.0 75.0 Polyethylene wax wt % 5.0 10.0 15.0 25.0 40.0 5.0 25.0 25.0 MFR.sub.2 g/10 min 4.9 6.2 8.7 16.7 79.0 5.5 23.6 29.8 Tc polyethylene wax C. 83.2 83.7 82.4 113.5 Tc polypropylene copolymer C. 105.0 105.5 105.6 107.7 106.4 115.0 113.0 107.5 Tm wax C. 126.0 125.5 126.4 126.6 127.3 126.0 127.7 126.1 Tm polypropylene copolymer C. 145.0 144.7 145.3 145.22 143.8 165.0 164.6 143.3 G23 C. MPa 375 369 381 401 506 838 844 508 G70 C. MPa 107 103 107 113 155 338 322 145 G70/G23 C. 0.3 0.3 0.3 0.3 0.3 0.4 0.4 0.3 Tg matrix C. 4.3 4.8 4.4 4.2 4.3 1.4 3.0 5.9 Tg rubber C. 47.0 45.8 42.5 46.8 48.6 n.m. n.m. n.m. Tg wax C. 124.8 n.m. 120.0 121.1 Tensile modulus, E MPa 731 808 869 872 875 1856 1855 1033 Tensile strength at break, TSB MPa 20.0 464 21.0 21.0 21.0 37.0 36.0 25.0 Tensile strength at yield, TSY MPa 20.0 21.0 21.0 21.0 21.0 37.0 36.0 25.0 Elongation at break, EAB % 526 464 302 99.0 10.0 88.0 5.0 56.0 Elongation at yield, EAY % 15.0 13.0 12.0 11.0 10.0 7.0 5.0 9.0 Flexibility 1.03 0.77 0.66 0.60 0.54 0.10 0.07 0.35 *n.m. = not measured

TABLE-US-00005 TABLE 5 Properties of adhesive compositions containing an ethylene- acrylate copolymer or an ethylene based plastomer*. Unit IE-10 IE-11 IE-12 IE-4 wt % 83.0 85.0 IE-7 wt % 90.0 Queo 8230 wt % 17.0 10.0 Elvaloy AC 1330 wt % 15.0 MFR.sub.2 g/10 min 9.0 7.5 8.3 XCS wt % 32.3 n.m. 19.6 IV XCS dl/g 1.19 n.m. 1.07 T.sub.m C. 141 140 131 Tg matrix C. 3.7 5.0 3.2 Tg rubbber C. 49.6 51.0 48.5 G23 C. MPa 290 326 365 G70 C. MPa 78 94 76 G70/G'23 C. 0.3 0.3 0.2 Vicat-A C. 103 114 113 Tensile modulus, E MPa 490 620 694 Tensile strength at MPa 14.6 22.0 21.0 break, TSB Tensile strength at MPa 14.6 22.0 21.0 yield, TSY Elongation at % 579 550 634 break, EAB Elongation at yield, % 16.5 16.0 12.0 EAY Flexibility 2.31 1.17 0.82 *n.m. = not measured