COMPOSITE COMPRISING A CELLULOSE-BASED FILLER

Abstract

Composite comprising a heterophasic propylene copolymer (HECO), a high density polyethylene, a cellulose-based filler and a compatibilizer.

Claims

1. A composite comprising (a) 32 to 89 wt.-%, based on the total weight of the composite, of a heterophasic propylene copolymer (HECO) comprising a (semicrystalline) polypropylene (PP) as a matrix in which an elastomeric propylene copolymer (EC) is dispersed; (b) 5.0 to 40 wt.-%, based on the total weight of the composite, of a high density polyethylene (HDPE) having a density in the range of 935 to 970 kg/m.sup.3; (c) 5.0 to 30 wt.-%, based on the total weight of the composite, of a cellulose-based filler (CF); and (d) 1.0 to 8.0 wt.-%, based on the total weight of the composite, of an adhesion promoter (AP), wherein the composite does not comprise (i) a further heterophasic propylene copolymer different to the heterophasic propylene copolymer (HECO) and (ii) a further (semicrystalline) polypropylene different to the (semicrystalline) polypropylene (PP) of the matrix of the heterophasic propylene copolymer (HECO).

2. The composite according to claim 1 consisting of (a) 32 to 89 wt.-%, based on the total weight of the composite, of a heterophasic propylene copolymer (HECO) comprising a (semicrystalline) polypropylene (PP) as a matrix in which an elastomeric propylene copolymer (EC) is dispersed; (b) 5.0 to 40 wt.-%, based on the total weight of the composite, of a high density polyethylene (HDPE) having a density in the range of 935 to 970 kg/m.sup.3; (c) 5.0 to 30 wt.-%, based on the total weight of the composite, of the cellulose-based filler (CF); (d) 1.0 to 8.0 wt.-%, based on the total weight of the composite, of an adhesion promoter (AP), and (e) optionally, one or more of alpha nucleating agents (NU) or additives (A).

3. The composite according to claim 1 consisting of (a) 32 to 89 wt.-%, based on the total weight of the composite, of a heterophasic propylene copolymer (HECO) comprising a (semicrystalline) polypropylene (PP) as a matrix in which an elastomeric propylene copolymer (EC) is dispersed; (b) 5.0 to 40 wt.-%, based on the total weight of the composite, of a high density polyethylene (HDPE) having a density in the range of 935 to 970 kg/m.sup.3; (c) 5.0 to 30 wt.-%, based on the total weight of the composite, of the cellulose-based filler (CF); (d) 1.0 to 8.0 wt.-%, based on the total weight of the composite, of an adhesion promoter (AP), (e) optionally up to 5 wt.-%, based on the total weight of the composite, of alpha nucleating agents (NU) and (f) optionally up to 8.0 wt.-%, based on the total weight of the composite, of additives (A).

4. The composite according to claim 1, wherein the heterophasic propylene copolymer (HECO) has a melt flow rate MFR.sub.2 (230? C., 2.16 kg) in the range of from 3.0 to 30.0 g/10 min.

5. The composite according to claim 1, wherein the heterophasic propylene copolymer (HECO) has a xylene cold soluble (XCS) fraction (25? C.) of from 15.0 to 50.0 wt.-%, based on the total weight of the heterophasic propylene copolymer (HECO).

6. The composite according to claim 1, wherein the heterophasic propylene copolymer (HECO) has a comonomer content of ?30.0 mol.-%, based on the heterophasic propylene copolymer (HECO).

7. The composite according to claim 1, wherein (a) comprises one or more of the (semicrystalline) polypropylene (PP) is a (semicrystalline) propylene homopolymer (H-PP) or the elastomeric propylene copolymer (EC) is an ethylene propylene rubber (EPR).

8. The composite according to claim 1, wherein the heterophasic propylene copolymer comprises an amorphous fraction (AM), the amorphous fraction (AM) of the heterophasic propylene copolymer (HECO) has a comonomer content in the range of 30.0 to 60.0 mol.-%, based on the amorphous fraction (AM) of the heterophasic propylene copolymer (HECO).

9. The composite according to claim 1, wherein the heterophasic propylene copolymer comprises an amorphous fraction (AM), the amorphous fraction (AM) of the heterophasic propylene copolymer (HECO) has an intrinsic viscosity (IV) in the range of 1.8 to 3.2 dl/g.

10. The composite according to claim 1, wherein the high density polyethylene (HDPE) has a melt flow rate MFR.sub.2 (190? C., 2.16 kg) in the range of from 0.1 to 30.0 g/10 min.

11. The composite according to claim 1, wherein the cellulose-based filler (CF) is selected from the group consisting of wood, flax, hem, jute, straw, rice, hardboard, cardboard, paper, pulp, raw cellulose, cellulose, cellulose acetate, cellulose triacetate, cellulose propionate, cellulose acetate propionate, cellulose acetate butyrate, nitrocellulose, methylcellulose, ethylcellulose, ethyl methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose (HPC), hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose (HPMC), ethyl hydoxyethyl cellulose, carboxymethyl cellulose (CMC), and any mixtures thereof.

12. The composite according to claim 1, wherein the cellulose-based filler (CF) has a volume moment mean (D[4.3]) diameter between 1 and 300 ?m.

13. The composite according to claim 1, wherein the adhesion promoter (AP) is selected from the group consisting of an acid modified polyolefin, an anhydride modified polyolefin and a modified styrene block copolymer.

14. The composite according to claim 1, wherein the nucleating agents (NU) are selected from the group consisting of (i) salts of monocarboxylic acids and polycarboxylic acids, and (ii) dibenzylidenesorbitol and C.sub.1-C.sub.8-alkyl-substituted dibenzylidenesorbitol derivatives, ethyldibenzylidenesorbitol or dimethyldibenzylidenesorbitol, or substituted nonitol-derivatives, and (iii) salts of diesters of phosphoric acid, and (iv) vinylcycloalkane polymer and vinylalkane polymer, and (v) mixtures thereof.

15. The composite according to claim 2, wherein the additives (A) are selected from the group consisting of acid scavengers, antioxidants, colorants, light stabilisers, plasticizers, slip agents, anti-scratch agents, dispersing agents, processing aids, lubricants, pigments, and mixtures thereof.

16. A molded article comprising a composite, wherein the composite comprises: (a) 32 to 89 wt.-%, based on the total weight of the composite, of a heterophasic propylene copolymer (HECO) comprising a (semicrystalline) polypropylene (PP) as a matrix in which an elastomeric propylene copolymer (EC) is dispersed; (b) 5.0 to 40 wt.-%, based on the total weight of the composite, of a high density polyethylene (HDPE) having a density in the range of 935 to 970 kg/m.sup.3; (c) 5.0 to 30 wt.-%, based on the total weight of the composite, of a cellulose-based filler (CF); and (d) 1.0 to 8.0 wt.-%, based on the total weight of the composite, of an adhesion promoter (AP), wherein the composite does not comprise (i) a further heterophasic propylene copolymer different to the heterophasic propylene copolymer (HECO) and (ii) a further (semicrystalline) polypropylene different to the (semicrystalline) polypropylene (PP) of the matrix of the heterophasic propylene copolymer (HECO).

17. The molded article according to claim 16 being an automotive article.

18. The composite according to claim 13, wherein the adhesion promoter (AP) is a maleic anhydride functionalized polypropylene.

19. The composite according to claim 14, wherein the salts of monocarboxylic acids and polycarboxylic acids comprise sodium benzoate or aluminum tert-butylbenzoate, wherein dibenzylidenesorbitol comprises 1,3:2,4 dibenzylidenesorbitol, wherein C.sub.1-C.sub.8-alkyl-substituted dibenzylidenesorbitol derivatives comprise methyldibenzylidenesorbitol, wherein ethyldibenzylidenesorbitol or dimethyldibenzylidenesorbitol comprises 1,3:2,4 di(methylbenzylidene) sorbitol), wherein substituted nonitol-derivatives comprise 1,2,3,-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]-nonitol, and wherein salts of diesters of phosphoric acid-comprise sodium 2,2-methylenebis (4,6,-di-tert-butylphenyl) phosphate or aluminium-hydroxy-bis[2,2-methylene-bis(4,6-di-t-butylphenyl)phosphate.

20. The composite according to claims 3, wherein the additives (A) are selected from the group consisting of acid scavengers, antioxidants, colorants, light stabilisers, plasticizers, slip agents, anti-scratch agents, dispersing agents, processing aids, lubricants, pigments, and mixtures thereof.

Description

EXAMPLES

[0278] 1. Definitions/Measuring Methods

[0279] 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.

[0280] Quantification of Microstructure by NMR Spectroscopy

[0281] Quantitative nuclear-magnetic resonance (NMR) spectroscopy was used to quantify the comonomer content of the polymers. 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 probehead at 125? C. using nitrogen gas for all pneumatics. Approximately 200 mg of material was dissolved in 3 ml of 1,2-tetrachloroethane-d.sub.2 (TCE-d.sub.2) along with chromium-(III)-acetylacetonate (Cr(acac).sub.3) resulting in a 65 mM solution of relaxation agent in solvent (Singh, G., Kothari, A., Gupta, V., Polymer Testing 28 5 (2009), 475). To ensure a homogenous solution, after initial sample preparation in a heat block, the NMR tube was further heated in a rotatary 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 (Zhou, Z., Kuemmerle, R., Qiu, X., Redwine, D., Cong, R., Taha, A., Baugh, D. Winniford, B., J. Mag. Reson. 187 (2007) 225; Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun. 2007, 28, 1128). A total of 6144 (6k) transients were acquired per spectra.

[0282] 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 Cheng, H. N., Macromolecules 17 (1984), 1950).

[0283] With characteristic signals corresponding to 2,1 erythro regio defects observed (as described in L. Resconi, L. Cavallo, A. Fait, F. Piemontesi, Chem. Rev. 2000, 100 (4), 1253, in Cheng, H. N., Macromolecules 1984, 17, 1950, and in W-J. Wang and S. Zhu, Macromolecules 2000, 33 1157) the correction for the influence of the regio defects on determined properties was required. Characteristic signals corresponding to other types of regio defects were not observed.

[0284] The comonomer fraction was quantified using the method of Wang et. al. (Wang, W-J., Zhu, S., Macromolecules 33 (2000), 1157) 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.

[0285] 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??))

[0286] Through the use of this set of sites the corresponding integral equation becomes:

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

using the same notation used in the article of Wang et. al. (Wang, W-J., Zhu, S., Macromolecules 33 (2000), 1157). Equations used for absolute propylene content were not modified.

[0287] The mole percent comonomer incorporation was calculated from the mole fraction:

E[mol %]=100*fE

[0288] The weight percent comonomer incorporation was calculated from the mole fraction:

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

[0289] The comonomer sequence distribution at the triad level was determined using the analysis method of Kakugo et al. (Kakugo, M., Naito, Y., Mizunuma, K., Miyatake, T. Macromolecules 15 (1982) 1150). This method was chosen for its robust nature and integration regions slightly adjusted to increase applicability to a wider range of comonomer contents.

[0290] DSC analysis, melting temperature (T.sub.m) and heat of fusion (H.sub.f), crystallization temperature (T.sub.c) and heat of crystallization (H.sub.c): measured with a TA Instrument Q2000 differential scanning calorimetry (DSC) on 5 to 7 mg samples. DSC is run according to ISO 11357/part 3 /method C.sub.2 in a heat/cool/heat cycle with a scan rate of 10? C./min in the temperature range of ?30 to +225? C. Crystallization temperature and heat of crystallization (H.sub.c) are determined from the cooling step, while melting temperature and heat of fusion (H.sub.f) are determined from the second heating step.

[0291] Density is measured according to ISO 1183-1-method A (2004). Sample preparation is done by compression moulding in accordance with ISO 1872-2:2007.

[0292] MFR.sub.2 (230? C.) is measured according to ISO 1133 (230? C., 2.16 kg load).

[0293] MFR.sub.2 (190? C.) is measured according to ISO 1133 (190? C., 2.16 kg load).

[0294] The xylene cold solubles (XCS, wt.-%): Content of xylene cold solubles (XCS) is determined at 25? C. according to ISO 16152; first edition; 2005-07-01

[0295] The amorphous content (AM) is measured by separating the above xylene cold soluble fraction (XCS) and precipitating the amorphous part with acetone. The precipitate was filtered and dried in a vacuum oven at 90? C.

[00001]$\mathrm{AM}.Math.\%=\frac{100*m.Math..Math.1*v.Math..Math.0}{m.Math..Math.0*v.Math..Math.1}$

[0296] wherein

[0297] AM % is the amorphous fraction,

[0298] m0 is initial polymer amount (g)

[0299] m1 is weight of precipitate (g)

[0300] v0 is initial volume (ml)

[0301] v1 is volume of analyzed sample (ml)

[0302] Intrinsic viscosity is measured according to DIN ISO 1628/1, October 1999 (in Decalin at 135? C.).

[0303] Flexural Modulus is determined in 3-point-bending according to ISO 178 on injection molded specimens of 80?10?4 mm.sup.3 prepared in accordance with EN ISO 1873-2.

[0304] Charpy notched impact strength is determined according to ISO 179/1eA at 23? C. by using injection moulded test specimens of 80?10?4 mm.sup.3 prepared in accordance with EN ISO 1873-2.

[0305] The particle size and particle size distribution of the cellulose-based fillers (CF), like wood flour fillers were determined by a Horiba Partica LA 950 V2 (Horiba Co., Japan) laser diffraction particle size analyzer equipped with an automated dry powder dispersion unit. Three parallel measurements were carried out and the result given is their average. The volume moment mean (D[4.3]) was calculated and used as mean particle size of cellulose-based fillers (CF), like the wood flour fillers.

[0306] The aspect ratio of the cellulose-based fillers (CF), like wood flour fillers was determined with the help of scanning electron microscopy (SEM). The SEM micrographs were taken by a Jeol JSM 6380 LA apparatus. The particles on the SEM micrographs were measured with the help of image analysis software (Image Pro Plus) and the length and diameter of the particles were measured individually by hand. At least 500 particles were analyzed on several micrographs in order to lower the standard deviation of the evaluation and aspect ratio was calculated thereof.

2. Examples

[0307] Preparation of HECO

[0308] Catalyst

[0309] First, 0.1 mol of MgCl.sub.2?3 EtOH was suspended under inert conditions in 250 ml of decane in a reactor at atmospheric pressure. The solution was cooled to the temperature of ?15? C. and 300 ml of cold TiCl.sub.4 was added while maintaining the temperature at said level. Then, 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. After the addition of the phthalate, the temperature was raised to 135? C. during 90 minutes and the slurry was allowed to stand for 60 minutes. Then, another 300 ml of TiCl.sub.4 was added and the temperature was kept at 135? C. for 120 minutes. After this, the catalyst was filtered from the liquid and washed six times with 300 ml heptane at 80? C. Then, the solid catalyst component was filtered and dried. Catalyst and its preparation concept is described in general e.g. in patent publications EP 491566, EP 591224 and EP 586390.

[0310] The catalyst was further modified (VCH modification of the catalyst). 35 ml of mineral oil (Paraffinum Liquidum PL68) was added to a 125 ml stainless steel reactor followed by 0.82 g of triethyl aluminium (TEAL) and 0.33 g of dicyclopentyl dimethoxy silane (donor D) under inert conditions at room temperature. After 10 minutes 5.0 g of the catalyst prepared above (Ti content 1,4 wt %) was added and after additionally 20 minutes 5.0 g of vinylcyclohexane (VCH) was added. The temperature was increased to 60? C. during 30 minutes and was kept there for 20 hours. Finally, the temperature was decreased to 20? C. and the concentration of unreacted VCH in the oil/catalyst mixture was analysed and was found to be 200 ppm weight.

TABLE-US-00001 TABLE 1 Polymerization of HECO HECO Prepoly Residence time [h] 0.08 Temperature [? C.] 30 Co/ED ratio [mol/mol] 7.3 Co/TC ratio [mol/mol] 220 Loop (R1) Residence time [h] 0.6 Temperature [? C.] 75 H.sub.2/C.sub.3 ratio [mol/kmol] 14.8 MFR.sub.2 [g/10 min] 55 XCS [wt %] 2.0 C2 content [wt %] 0 split [wt %] 30 1.sup.st GPR (R2) Residence time [h] 0.75 Temperature [? C.] 80 Pressure [kPa] 2200 H.sub.2/C.sub.3 ratio [mol/kmol] 149.7 MFR.sub.2 [g/10 min] 55 XCS [wt %] 2.0 C2 content [wt %] 0 split [wt %] 35 2.sup.nd GPR (R3) Residence time [h] 0.6 Temperature [? C.] 70 Pressure [kPa] 2190 C.sub.2/C.sub.3 ratio [mol/kmol] 584.6 H.sub.2/C.sub.2 ratio [mol/kmol] 116.5 MFR.sub.2 [g/10 min] 11 C2 content [wt %] 8.5 split [wt %] 20 3.sup.rd GPR (R4) Residence time [h] 0.6 Temperature [? C.] 85 Pressure [kPa] 1320 C.sub.2/C.sub.3 ratio [mol/kmol] 585.2 H.sub.2/C.sub.2 ratio [mol/kmol] 92.7 MFR.sub.2 [g/10 min] 11 C2 content [wt %] 13 split [wt %] 15

[0311] The properties of the products obtained from the individual reactors naturally are not measured on homogenized material but on reactor samples (spot samples). The properties of the final resin are measured on homogenized material, the MFR.sub.2 on pellets made thereof in an extrusion mixing process as described below.

[0312] The HECO was mixed in a twin-screw extruder with 0.1 wt % of Pentaerythrityl-tetrakis(3-(3,5-di-tert. butyl-4-hydroxyphenyl)-propionate, (CAS-no. 6683-19-8, trade name Irganox 1010) supplied by BASF AG, 0.1 wt % Tris (2,4-di-t-butylphenyl) phosphate (CAS-no. 31570-04-4, trade 10 name Irgafos 168) supplied by BASF AG, and 0.05 wt % Calcium stearate (CAS-no. 1592-23-0) supplied by Croda Polymer Additives.

TABLE-US-00002 TABLE 2 Properties of HECO HECO H-PP (1.sup.st and 2.sup.nd reactor) [wt %] 65 MFR.sub.2 of H-PP (1.sup.st and 2.sup.nd reactor) [g/10 min] 55 Tm of H-PP (1.sup.st and 2.sup.nd reactor) [? C.] 165 EPR (3.sup.rd and 4.sup.th reactor) [wt %] 35 C2 of EPR (3.sup.rd and 4.sup.th reactor) [mol %] 47 C2 of AM [mol %] 47.9 IV of AM [dl/g] 2.5 XCS (final) [wt %] 32 C2 (total) [mol %] 18.3 MFR.sub.2 (230? C.) (final) [g/10 min] 11 AM amorphous fraction C2 ethylene content MFR.sub.2 is MFR.sub.2 (230? C.; 2.16 kg)

TABLE-US-00003 TABLE 3a Inventive Examples Example IE1 IE2 IE1 1E2 HECO [wt %] 68 63 53 48 HDPE [wt %] 10 15 25 30 CF [wt %] 20 20 20 20 AP [wt %] 2 2 2 2 MFR.sub.2 (230? C.) [g/10 min] 5.7 5.0 4.3 4.0 FM [MPa] 1330 1350 1340 1340 NIS [kJ/m.sup.2] 10.2 9.6 10.4 9.9

TABLE-US-00004 TABLE 3b Comparative Examples Example CE1 CE2 CE3 HECO [wt %] 100 73 28 HDPE [wt %] 0 5 50 CF [wt %] 0 20 20 AP [wt %] 0 2 2 MFR.sub.2 (230? C.) [g/10 min] 11.4 5.8 3.7 FM [MPa] 910 1420 1480 NIS [kJ/m.sup.2] 53 9.2 8.7 HDPE is the commercial high density polyethylene BS4541 of Borealis AG having a MFR.sub.2 (190? C./2.16 kg) of 0.7 g/10 min and a density of 964 kg/m.sup.3. CF is the commercial cellulosic Filtracel EFC 1000 of Rettenmaier und S?hne having a volume moment mean (D[4.3]) diameter of 162.9 ?m and an aspect ratio of 4.2. AP is the commercial propylene homopolymer Scona TPPP 2112 FA of BYK Cometra (Germany) having a maleic anydride content of 1.1 wt-%, and a melt flow rate MFR.sub.2 (230? C.; 2.16 kg) of 12 g/10 min. FM is the flexural modulus NIS is the notched impact strength