Reinforced Polyolefin Composition Comprising Recycled Plastic Material

Abstract

Provided is a polyolefin composition including a blend of recycled plastic material including polyproplyene and polyethylene, which is recovered from a waste plastic material derived from post-consumer and/or post-industrial waste; glass fibres; talc; at least one coupling agent; and at least one impact modifier. The polyolefin composition has a tensile modulus of at least 4 GPa, and an impact strength of at least 10 kJ/m.sup.2.

Claims

1. A polyolefin composition comprising a) 7-82.5 wt % of a blend of recycled plastic material comprising polypropylene and polyethylene, which is recovered from a waste plastic material derived from post-consumer and/or post-industrial waste; b) 10-40 wt % of glass fibres; c) 5-30 wt % talc; d) 0.5-3 wt % of at least one coupling agent; and e) 2-20 wt % of at least one impact modifier, wherein the polyolefin composition is preferably free of any virgin polyethylene and has a tensile modulus of at least 4 GPa, and an impact strength of at least 10 kJ/m.sup.2.

2. The polyolefin composition according to claim 1, having a tensile modulus of at least 5 GPa, more preferably at least 5.5 GPa, and even more preferably at least 6 GPa, and an impact strength of at least 15 kJ/m.sup.2, more preferably at least 17 kJ/m.sup.2 and even more preferably of at least 20 kJ/m.sup.2.

3. The polyolefin composition according to claim 1, wherein the tensile modulus of the polyolefin composition is between 4 and 7 GPa, preferably between 4.5 and 6 GPa, and the impact strength is between 10 and 25 kJ/m.sup.2, preferably between 15 and 22 kJ/m.sup.2, preferably between 17 and 20 kJ/m.sup.2.

4. The polyolefin composition according to claim 1, wherein the blend of recycled plastic material comprises at least 50 wt %, preferably at least 60 wt %, more preferably at least 70 wt %, and even more preferably at least 80 wt % polypropylene.

5. The polyolefin composition according to claim 1, wherein the blend of recycled plastic material comprises at least 10 wt %, preferably at least 30 wt %, more preferably at least 40 wt % polyethylene.

6. The polyolefin composition according to claim 1, wherein the blend of recycled plastic material comprises A-1) a content of polypropylene of 30-98 wt.-%, A-2) a content of polyethylene of 2-50 wt.-% A-3) 0 to 5.0 wt.-% of polystyrene, A-4) 0 to 3.0 wt.-% stabilizers, A-5) 0 to 4.0 wt.-% polyamide-6, A-6) 0 to 3.0 wt.-% talc, A-7) 0 to 3.0 wt.-% chalk, A-8) 0 to 1.0 wt.-% paper, A-9) 0 to 1.0 wt.-% wood, A-10) 0 to 0.5 wt.-% metal, A-11) 0.1 ppm to 100 ppm of limonene as determined by using solid phase microextraction (HS-SPME-GC-MS), and A-12) 0 to 200 ppm total fatty acid content as determined by using solid phase microextraction (HS-SPME-GC-MS), wherein all amounts are given with respect to the total weight of

7. The polyolefin composition according to claim 1, wherein the melt flow rate (ISO 1133, 2.16 kg, 230° C.) of the polyolefin composition is between 0.5 and 6 g/10 min, preferably between 1.5 and 5 g/10 min, more preferably between 2 and 4 g/10 min, and the density of the polyolefin composition is between 800 and 1500 kg/m.sup.3, preferably between 850 and 1300 kg/m.sup.3, more preferably between 900 and 1100 kg/m.sup.3.

8. The polyolefin composition according to claim 1, wherein the glass fibers have a length of 2.0 to 10.0 mm, preferably in the range of 2.0 to 8.0 mm, even more preferably in the range of 2.0 to 6.0 mm and a diameter of from 5 to 20 μm, more preferably from 8 to 18 μm, still more preferably 8 to 15 μm.

9. The polyolefin composition according to claim 1, wherein the talc comprises particles with a size d.sub.50 of 2.5-5 μm, preferably of 3.0-4.5 μm, more preferably of 3.5-4.0 μm.

10. The polyolefin composition according to claim 1, wherein the at least one coupling agent is a functionalized polypropylene, in particular a polypropylene functionalized with maleic anhydride (MAH).

11. The polyolefin composition according to claim 1, having 5-12 wt %, preferably by 8-10 wt % of the impact modifier, in particular an ethylene based 1-octene elastomer.

12. The polyolefin composition according to claim 1, further comprising further additives, in particular carbon black, at least one antioxidant and/or at least one UV stabilizer.

13. (canceled)

14. An article comprising the polyolefin composition according to claim 1.

15. A process for preparing the polyolefin composition according to claim 1, comprising the steps of providing a mixture of the blend, glass fibers, talc, a coupling agent and an impact modifier in the required amounts; melting the mixture in an extruder, and optionally pelletizing the obtained polyolefin composition.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0122] The proposed solution is now explained in more detail with reference to the examples.

[0123] FIG. 1 shows a diagram illustrating the tensile modulus and impact strength of recyclates blend (A) used for reinforced polyolefin composition composites.

[0124] FIG. 2 shows a diagram illustrating the tensile modulus and impact strength of polyolefin compositions with elastomer.

DESCRIPTION OF THE INVENTION

Experimental Section

[0125] The following Examples are included to demonstrate certain aspects and embodiments of the solution as described in the claims. It should be appreciated by those of skill in the art, however, that the following description is illustrative only and should not be taken in any way as a restriction of the solution.

Test Methods

[0126] a) Amount of iPP, Polystyrene, Content of ethylene (andeEthylene containing copolymers) and Amount of Polyamide-6

[0127] To establish different calibration curves different standards, iPP and HDPE and iPP, PS and PA6 were blended. For the quantification of the content of the foreign polymers, IR spectra were recorded in the solid-state using a Bruker Vertex 70 FTIR spectrometer. Films were prepared with a compression-moulding device at 190° C. with 4-6 MPa clamping force. The thickness of the films for the calibration standards for iPP and HDPE was 300 pm and for the quantification of the iPP, PS and PA 6 50-100 μm film thickness was used. Standard transmission FTIR spectroscopy is employed using a spectral range of 4000-400 cm.sup.−1, an aperture of 6 mm, a spectral resolution of 2 cm.sup.−1, 16 background scans, 16 spectrum scans, an interferogram zero filling factor of 32 and Norton Beer strong apodisation.

[0128] The absorption of the band at 1167 cm.sup.−1 in iPP is measured and the iPP content is quantified according to a calibration curve (absorption/thickness in cm versus iPP content in weight %).

[0129] The absorption of the band at 1601 cm.sup.−1 (PS) and 3300 cm.sup.−1 (PA6) are measured and the PS and PA6 content quantified according to the calibration curve (absorption/thickness in cm versus PS and PA content in wt %). The content of polyethylene and ethylene containing copolymers is obtained by subtracting (iPP+PS+PA6) from 100, taking into account the content of non-polymeric impurities as determined in the methods below. The analysis is performed as a double determination.

b) Amount of Talc and Chalk

[0130] were measured by Thermogravimetric Analysis (TGA); experiments were performed with a Perkin Elmer TGA 8000. Approximately 10-20 mg of material was placed in a platinum pan. The temperature was equilibrated at 50° C. for 10 minutes, and afterwards raised to 950° C. under nitrogen at a heating rate of 20 ° C./min. The weight loss between ca. 550° C. and 700° C. (WCO2) was assigned to CO2 evolving from CaCO3, and therefore the chalk content was evaluated as:

Chalk content=100/44×WCO2

[0131] Afterwards the temperature was lowered to 300° C. at a cooling rate of 20 ° C./min. Then the gas was switched to oxygen, and the temperature was raised again to 900° C. The weight loss in this step was assigned to carbon black (Wcb). Knowing the content of carbon black and chalk, the ash content excluding chalk and carbon black was calculated as:

Ash content=(Ash residue)−56/44×WCO2−Wcb

[0132] Where Ash residue is the weight % measured at 900° C. in the first step conducted under nitrogen. The ash content is estimated to be the same as the talc content for the investigated recyclates. [0133] c) Amount of Paper, Wood

[0134] Paper and wood were determined by conventional laboratory methods including milling, floatation, microscopy and Thermogravimetric Analysis (TGA). [0135] d) Amount of Metals was determined by x ray fluorescence (XRF). [0136] e) Amount of Limonene was determined by solid phase microextraction (HS-SPME-GC-MS). Additional details are given below with respect to the specific sample. [0137] f) Amount of total fatty acids was determined by solid phase microextraction (HS-SPME-GC-MS). Additional details are given below with respect to the specific sample. [0138] g) Melt flow rates were measured with a load of 2.16 kg (MFR.sub.2) at 230° C. or 190° C. as indicated. The melt flow rate is that quantity of polymer in grams which the test apparatus standardized to ISO 1133 extrudes within 10 minutes at a temperature of 230° C. (or 190° C.) under a load of 2.16. [0139] h) Tensile modulus was measured according to ISO 527-2 (cross head speed =1 mm/min; test speed 50 mm/min at 23 ° C.) using compression moulded specimens as described in EN ISO 1873-2 (dog bone shape, 4 mm thickness). The measurement was done after 96 h conditioning time of the specimen. [0140] i) Impact strength was determined as Charpy Notched Impact Strength according to ISO 179-1 eA at +23 ° C. on injection moulded specimens of 80×10×4 mm prepared according to EN ISO 1873-2. According to this standard samples are tested after 96 hours.

EXAMPLE 1

Reinforced PP Rich Blend (Recyclate 1, 2)

[0141] a) PP rich Blend A (recyclate 1, 2) has the following composition [0142] PP content of >80 wt % (second main constituent is PE) [0143] PS (polystyrene) <1 wt % [0144] PA (polyamide) <0.5 wt % [0145] PET traces [0146] Talc <3 wt % [0147] Chalk <1 wt % [0148] TiO.sub.2 traces [0149] small amounts (<1 wt %) of paper, wood can also be present

[0150] Limonene quantification was carried out using solid phase micro-extraction (HS-SPME-GC-MS) by standard addition.

[0151] 50 mg ground samples were weighed into 20 mL headspace vials and after the addition of limonene in different concentrations and a glass-coated magnetic stir bar, the vial was closed with a magnetic cap lined with silicone/PTFE. Micro capillaries (10 μL) were used to add diluted limonene standards of known concentrations to the sample. Addition of 0, 2, 20 and 100 ng equals 0 mg/kg, 0.1 mg/kg, 1mg/kg and 5 mg/kg limonene, in addition standard amounts of 6.6, 11 and 16.5 mg/kg limonene were used in combination with some of the samples tested in this application. For quantification, ion-93 acquired in SIM mode was used. Enrichment of the volatile fraction was carried out by headspace solid phase micro-extraction with a 2 cm stable flex 50/30 pm DVB/Carboxen/PDMS fibre at 60° C. for 20 minutes. Desorption was carried out directly in the heated injection port of a GCMS system at 270° C. [0152] GCMS Parameters: [0153] Column: 30 m HP 5 MS 0.25*0.25 [0154] Injector: Splitless with 0.75 mm SPME Liner, 270° C. [0155] Temperature program: -10° C. (1 min) [0156] Carrier gas: Helium 5.0, 31 cm/s linear velocity, constant flow [0157] MS: Single quadrupole, direct interface, 280° C. inter face temperature [0158] Acquisition: SIM scan mode [0159] Scan parameter: 20-300 amu [0160] SIM Parameter: m/Z 93, 100 ms dwell time

TABLE-US-00001 TABLE 1 Limonene content in PP rich blend A (recyclate 1, 2) Limonene [mg/kg] Sample HS-SPME-GC-MS.sup.1 PP rich blend A 2.6 ± 0.1 .sup.1Headspace Soldiphase Microextraction.

[0161] Fatty acid quantification was carried out using headspace solid phase micro-extraction (HS-SPME-GC-MS) by standard addition.

[0162] 50 mg ground samples were weighed in 20 mL headspace vial and after the addition of limonene in different concentrations and a glass coated magnetic stir bar the vial was closed with a magnetic cap lined with silicone/PTFE. 10 μL Micro-capillaries were used to add diluted free fatty acid mix (acetic acid, propionic acid, butyric acid, pentanoic acid, hexanoic acid and octanoic acid) standards of known concentrations to the sample at three different levels. Addition of 0, 50, 100 and 500 ng equals 0 mg/kg, 1 mg/kg, 2 mg/kg and 10 mg/kg of each individual acid. For quantification ion 60 acquired in SIM mode was used for all acids except propanoic acid, here ion 74 was used. [0163] GCMS Parameter: [0164] Column: 20 m ZB Wax plus 0.25*0.25 [0165] Injector: Split 5:1 with glass lined split liner, 250° C. [0166] Temperature program: 40° C. (1 min) @6° C./min to 120° C., @15° C. to 245 ° C. (5 min) [0167] Carrier: Helium 5.0, 40 cm/s linear velocity, constant flow [0168] MS: Single quadrupole, direct interface, 220° C. inter face temperature [0169] Acquisition: SIM scan mode [0170] Scan parameter: 46-250 amu 6.6 scans/s [0171] SIM Parameter: m/z 60, 74, 6.6 scans/s

TABLE-US-00002 TABLE 2 Total fatty acid content in PP rich blend A (recyclate 1, 2) Total fatty acid Sample concentration [mg/kg].sup.1 PP rich blend A 28.7 .sup.1The concentration of acetic acid, propionic acid, butyric acid, pentanoic acid, hexanoic acid, octanoic acid, nonanoic acid and decanoic acid in each sample was added together to give a totally fatty acid concentration value. [0172] b) Reinforced PP rich blend A (recylate 1, 2) has the following composition: [0173] 45 wt % PP rich blend A (recyclate 1, 2), [0174] 30 wt % glass fibers 1 (average length 4 mm, average diameter 13 μm), [0175] 10 wt % talc 1 (particle size d.sub.50 of about 3.5-5.0 μm), [0176] 10% ethylene based 1-octene elastomer as impact modifier; [0177] 1.5 wt % polypropylene functionalized with maleic anhydride (MAH) as coupling agent; [0178] 1 wt % carbon black; [0179] 0.25wt % AO200GRA (Tris (2,4-di-t-butylphenyl) phosphite); [0180] 0.25wt % AO102GRA (Octadecyl 3-(3′,5′-di-tert. butyl-4-hydroxyphenyl)propionate); [0181] 0.38 wt % UV575PEL; and [0182] 0.15wt % UV256PAS

EXAMPLE 2

Reinforced PE Rich Blend A (Recyclate 4)

[0183] a) PE rich Blend A (recyclate 4) from the yellow bag system has the following composition [0184] PE content of >27 wt % (main constituent of the blend is PP) [0185] PS (polystyrene) <5 wt % [0186] PA (polyamide) <1 wt % [0187] PET traces [0188] Talc <1 wt % [0189] Chalk <9 wt % [0190] TiO.sub.2 traces [0191] small amounts (<1 wt %) of paper and wood can also be present

[0192] Limonene quantification was carried out using solid phase microextraction (HS-SPME-GC-MS) by standard addition as described above for recyclate 1, 2

TABLE-US-00003 TABLE 3 Limonene [mg/kg] content in PE rich blend A (recyclate 4) PE rich blend A (recyclate 4) 31.5 ± 2.6

[0193] Fatty acid quantification was carried out using headspace solid phase micro-extraction (HS-SPME-GC-MS) by standard addition as described above for recyclate 1, 2.

TABLE-US-00004 TABLE 4 Total fatty acid concentration [mg/kg] in PE rich blend A (recyclate 4) PE rich blend A (recyclate 4) 70.6 .sup.1The concentration of acetic acid, propionic acid, butyric acid, pentanoic acid, hexanoic acid, octanoic acid, nonanoic acid and decanoic acid in each sample was added together to give a totally fatty acid concentration value. [0194] b) Reinforced PE rich blend A (recyclate 4) has the following composition: [0195] 45 wt % PE rich blend A (recyclate 4), [0196] 30 wt % glass fibers 1 (average length 4 mm, average diameter 13 μm), [0197] 10 wt % talc 1 (particle size d.sub.50 of about 3.5-5.0 μm), [0198] 10% ethylene based 1-octene elastomer as impact modifier; [0199] 1.5 wt % polypropylene functionalized with maleic anhydride (MAH) as coupling agent; [0200] 1 wt % carbon black; [0201] 0.25wt % AO200GRA(Tris (2,4-di-t-butylphenyl) phosphite); [0202] 0.25wt % AO102GRA (Octadecyl 3-(3′,5′-di-tert. butyl-4-hydroxyphenyl)propionate); [0203] 0.38 wt % UV575PEL; and [0204] 0.15wt % UV256PAS

EXAMPLE 3

Determining Tensile Modulus and Impact Strength

[0205] All of the examples shown in the diagrams of FIGS. 1 and 2 have been produced according to standard procedures.

[0206] A wide range of recyclates with different PE/PP content as well as mixtures thereof as base resin for inventive GF/Talc composites were used. The diagram of FIG. 1 provides an overview of stiffness-impact strength of recyclates 1-4 used for GF/talc reinforced composites (recyclates 1 and 2 are PP rich blends, and recyclates 3 and 4 are PE enriched or PE rich blends).

[0207] The virgin resins HECO-PP1, HECO-PP2 and Homo-PP1 were used together as base resin for PP-GF-T (virgin base resin for composite 1). The Homo-PP2 was also mixed with a Non Prime homo PP grade, as base resin for PP-GF (virgin base resin for composite 2). These resins have different tensile modulus and similar NIS (See FIG. 1).

[0208] For comparisons the virgin base resins of PP-GF-T (composite 1) and PP-GF (composite 2) were also shown in FIG. 1. In these examples a wide range of stiffness/impact strength can be seen for virgin and recyclates.

[0209] The diagram of FIG. 2 shows the tensile modulus and notched impact strength (NIS) of some of the inventive composites based on different recyclates/blend of recyclates (recyclate 1, 2 and 4) with 10% elastomer, with 30% Glass fibers 1 (average length 4 mm, average diameter 13 μm) and 10% Talc 1 (particle size d.sub.50 of about 3.5-5.0 μm), as well as current commercial grade PP-GF-T based on virgin PP matrix and 20% finer Glass 3 (average length 3 mm, average diameter 10.5 μm) and 10% higher aspect ratio Talc 3 (d.sub.50 of about 1.3±0.2 μm) (composite 1), as well asPP-GF based on virgin PP and 30% Glass 2 (average length 4.5 mm, average diameter 13 μm), (composite 2)

[0210] The diagram of FIG. 2 provides an overview of stiffness-impact strength of inventive composites based on recyclates (recyclate 1, recyclate 2 and recyclate 4) with 10% elastomer, and all with 30 wt % Glass 1 (average length 4 mm, average diameter 13 μm) and 10 wt % Talc 1 (particle size d.sub.50 of about 3.5-5.0 μm). Two commercial grades PP-GF-T (composite 1) and PP-GF (composite 2) are based on virgin PP, and 20 wt % Glass 3/10 wt % Talc2 and 30 wt % Glass 2 (average length 4.5 mm, average diameter 13 μm), (without talc), respectively.

[0211] As can be seen in FIG. 2 the tensile modulus as well as the impact strength of reinforced recycled based composites can be improved (Examples 1, 2, 3) when compared to recyclates 1-4 without any glass fibers, talc and impact modifier (see FIG. 1) . It can also be seen that by adding only 10 wt % impact modifier the NIS can be improved to 15 to 22 kJ/m.sup.2, whereby the tensile modulus is 6 to 4.5 GPa (see examples 4-6).

[0212] These results show that the virgin matrix can be replaced with recyclates and even better impact strength with only 10% elastomer as impact modifier. For instance, Example 5 (recyclate 2 with 10% elastomer) results in the same stiffness as composite 1 but higher impact strength 17 kJ/m.sup.2.