FIBER POLYMER COMPOSITE

Abstract

The present invention relates to fiber polymer composite comprising polypropylene fibers and a matrix material, the matrix material being in direct contact with at least some of the fibers, characterized in that the matrix material comprises 50% to 100% by weight based on the whole matrix material of an amorphous propylene-rich poly-alpha-olefin, to a process for producing the fiber polymer composite, and to the use of the fiber polymer composite.

Claims

1. A fiber polymer composite comprising fibers of a first material selected from polypropylene fibers and a matrix material, the matrix material being in direct contact with at least some of the fibers, wherein the matrix material comprises 50% to 100% by weight based on the whole matrix material of an amorphous propene-rich poly-alpha-olefin, having a melt viscosity at 190° C. of less than 200 Pas, having a number average molecular weight M.sub.n of from 5000 to 35000 g/mol, having a weight average molecular weight M.sub.w of from 50000 to 150000 g/mol, having a glass transition temperature of from −45 to −20° C., and having a softening point of from 95 to 125° C., each determined by the methods specified in the description.

2. The fiber polymer composite as claimed in claim 1, wherein the first material fibers are selected from polypropylene fibers have a melting temperature T.sub.m determined by DSC of above 160° C., preferably above 165° C.

3. The fiber polymer composite as claimed in claim 1, wherein the amorphous poly-alpha-olefin has a melt viscosity at 190° C. of from 5 to 150 Pas, determined by the method specified in the description.

4. The fiber polymer composite as claimed in claim 1, wherein the amorphous poly-alpha-olefin has a number average molecular weight M.sub.n of from 10000 to 25000 g/mol, determined by the method specified in the description.

5. The fiber polymer composite as claimed in claim 1, wherein the amorphous poly-alpha-olefin has a weight average molecular weight M.sub.w of from 70000 to 125000 g/mol, determined by the method specified in the description.

6. The fiber polymer composite as claimed in claim 1, wherein the amorphous poly-alpha-olefin has a molecular weight distribution (M.sub.w/M.sub.n) of from 4 to 8, more preferably 4.5 to 7.5, determined by the method specified in the description.

7. The fiber polymer composite as claimed in claim 1, wherein the amorphous poly-alpha-olefin has a glass transition temperature of from −40 to −25, most preferably of from −35 to −25, determined by the method specified in the description.

8. The fiber polymer composite as claimed in claim 1, wherein the amorphous poly-alpha-olefin has a thermal stability under load S.A.F.T. of from 75 to 130° C., more preferably of from 80 to 120° C. and most preferably of from 85 to 100° C., determined by the method specified in the description.

9. The fiber polymer composite as claimed in claim 1, wherein the amorphous poly-alpha-olefin has a softening point of from 100 to 115° C., and most preferably of from 105 to 110° C., determined by the method specified in the description.

10. The fiber polymer composite as claimed in claim 1, wherein the amorphous poly-alpha-olefin is based to an extent of >50% by weight on propene as monomer, and the sum total of 1-butene and ethene as monomer is <50% by weight, preferably with an ethene content>0% to 15% by weight, based on all monomers.

11. A process for producing fiber polymer composite as claimed in claim 1, wherein it comprises the following steps: a) providing a structure comprising one or more fibres selected from polypropylene fibers b) contacting at least one side of the structure with an propylene-rich amorphous poly-alpha-olefin, having a melt viscosity at 190° C. of less than 200 Pas, having a number average molecular weight M.sub.n of from 5000 to 35000 g/mol, having a weight average molecular weight M.sub.w of from 50000 to 150000 g/mol, having a glass transition temperature of from −45 to −20° C., and having a softening point of from 95 to 125° C., each determined by the methods specified in the description, c) optionally contacting the amorphous poly-alpha-olefin with one side of a further structure comprising one or more fibres selected from polypropylene fibers, d) optionally repeating steps b) and c) one or more times, and e) treating the product resulting from step b), c) or d) thermally by applying a temperature of from 115 to 145° C., preferably 120 to 140° C. and a pressure of at least 0.2 MPa.

12. The process as claimed in claim 11, wherein the amorphous poly-alpha-olefin is brought to contact with the structure comprising one or more fibers by applying a film or a dispersion of the of the amorphous poly-alpha-olefin.

13. A flexible tape comprising or consisting of fiber polymer composites as claimed in claim 1.

14. A reinforce article comprising or consisting of fiber polymer composite as claimed in claim 1.

Description

EXAMPLES

Fiber Comprising Materials Used:

[0057] Fabric 1: composed of highly stretched split PP tapes (woven fabric of split PP yarn) with a nominal weight of 200 g/m.sup.2 (Tiszatextil Ltd., Tiszaújváros, Hungary). The reinforcing tape has a melting temperature T.sub.m of 168.6° C. (determined by DSC), and a tensile strength of 280±12 MPa (measured on a single tape).

[0058] Fabric 2: composed of high strength PP multifilament with a nominal weight of 178 g/m.sup.2. (Lanex a.s., Bolatice, Czech Republic). The reinforcing fiber has a melting temperature T.sub.m of 171.6° C. (determined by DSC), and a tensile strength of 558±26 MPa. Its diameter is 27.6±0.6 μm (measured on single fibers). The woven fabric of high-tenacity is prepared in a small quantity by Csendes és Csendes Ltd. (Szigetbecse, Hungary) upon our request, so its accessibility is limited.

Matrix Material Used:

[0059] As matrix material, four different propene-rich VESTOPLAST® grades (708, 750, 792, 888; provided by Evonik Resource Efficiency GmbH, Marl, Germany) were used. The properties and compositions of the VESTOPLAST® grades used are listed in Table 1.

TABLE-US-00002 TABLE 1 Main properties of the four VESTOPLAST ® grades VESTOPLAST ® VESTOPLAST ® VESTOPLAST ® VESTOPLAST ® Properties 708 750 792 888 Melt viscosity at 8 50 120 120 190° C. (Pas) Molecular weight 11,500/75,000 18,100/92,000 23,800/118,000 15,000/104,000 Mn/Mw (g/mol) Density (g/cm3) 0.87 0.87 0.87 0.87 Glass transition −33 −33 −27 −36 temperature, Tg (DSC) (° C.) Softening point 106 107 108 161 (Ring & Ball) (° C.) Thermal stability 85-90 85-90 90-95 115-120 under load S.A.F.T. (° C.) Tensile strength 1.0 5.0 5.8 2.5 (MPa) Elongation at 330 1000 1200 850 break (%) Shear modulus at 4.0 14.0 7.0 3.5 23° C. (MPa)

[0060] Determination of the density at 23° C. according to DIN EN ISO 1183-1.

[0061] Determination of Tensile Strength/Elongation at Break according to DIN EN ISO 527-3, modified type 5. The tensile strength describes the tensile and elongation properties of a specimen type 3 with 2 mm thickness.

[0062] Determination of the Shear Modulus at 23° C. according to DIN EN ISO 6721-2. This part specifies the general principles of a method for determining the dynamic rheological properties of polymer melts, part 2 described the Torsion-pendulum method.

[0063] The content of the monomers the APAOs are based on can be determined using high temperature .sup.13C-NMR spectroscopy as described above.

[0064] Differential scanning calorimetry (DSC) was performed on the VESTOPLAST® samples and the reinforcing fiber and tape. It was found that a very wide processing window exists based on the difference in the melting ranges of VESTOPLAST® and PP tape. This ensures that composites can even be manufactured at a relatively low processing temperature avoiding the molecular relaxation of the reinforcement (which causes a prominent loss in both stiffness and strength and thus reducing its reinforcing effect). However, compared to the VESTOPLAST® 700 series, VESTOPLAST® 888 exhibits a different melting behavior. VESTOPLAST® 888 has a small melting peak around 160° C., so below this temperature it cannot be processed by extrusion at all. For stable processing and coating, a die temperature of 180° C. was necessary. This temperature accelerates the molecular relaxation of the reinforcement to be coated, even at a fast pulling speed and thereby short residence time in this temperature range.

[0065] Instrumented falling weight impact (IFWI) tests were performed (the method is described in detail under example 4 below). The results of room temperature tests gave the highest energy absorption capability—instead of VESTOPLAST® 888 of which the result of −40° C. proved unexpectedly high energy absorption.

Example 1: Preparing Fiber Polymer Composites

[0066] The fiber polymer composites were produced using a fabric guiding equipment that was mounted to a cast film extrusion line Labtech LE 25−30C (Labtech Engineering Co., Samutprakarn, Thailand). The slot die is 200 mm wide and the gap can be set between 0.1 to 1.0 mm. During production, the equipment guides the reinforcing fabric (200 mm wide) to the flat film die of the extruder, where the matrix film is extruded directly onto the fabric. After extrusion, the coated fabric is guided towards a winder by polytetrafluoroethylene (PTFE) rollers while it cools down. In order to avoid the coated fabric to stick together, a PTFE film is also added during the winding process.

[0067] The fiber content of the composites is defined by the thickness of the matrix films, and the extent of the relaxation phenomenon of the fabric during consolidation/compaction. The thickness of the matrix films is determined by the following parameters of the extrusion:

the rotating speed of the extruder screw,
the distance between the die lips,
the pulling speed of the coated fabric.

[0068] Due to the adhesion between the matrix material film and the reinforcing fabric, they cannot be separated; consequently, the thickness of the matrix film cannot be measured directly. Nevertheless, the thickness of the matrix film can be calculated after measuring the width of the fabric, the width of the matrix layer, and the length and weight of the coated fabric, using the following equation: h=(m−b.sub.flρA,f)/(ρv.sub.pbv.sub.pl), where his the thickness of the matrix film, m is the weight of the coated fabric, b.sub.f is the width of the coated fabric, l is the length of the coated fabric, ρ.sub.A,f is the areal density of the fabric, ρ.sub.Vp is the density of the matrix material and b.sub.Vp is the width of the matrix material coating.

[0069] To achieve a fiber content of the composites of between 70 to 80 wt %, the thickness of the matrix material layer was chosen to be around 60 μm.

[0070] Preliminary tests were conducted in order to specify the above-mentioned extrusion parameters to achieve a 60 μm film thickness. In these tests the rotating speed of the extruder screw and the distance between the die lips were 70 min-1 and 0.5 mm, respectively, the pulling speed of the coated fabric was altered in the range of 3 to 10 m/min, using a step of 0.5 m/min, and the rotating speed of the winder was set accordingly. The thickness of the matrix material film was calculated in each point and the required pulling speed to achieve 60 μm film thickness was determined by linear interpolation. The required pulling speeds for all matrices are summarized in Table 2. The temperature of the die was 120° C. for VESTOPLAST® 708, 750 and 792 and 180° C. for VESTOPLAST® 888 (only at this temperature the stable production could be ensured). The first roll was heated up to 40° C. The resulting coated fabrics were 55-65 μm thick and 150-160 mm wide depending on the viscosity and the pulling speed.

TABLE-US-00003 TABLE 2 Required pulling speed to achieve 60 μm film thickness Pulling speed Matrix material (m/min) VESTOPLAST ® 708 7.4 VESTOPLAST ® 750 8.9 VESTOPLAST ® 792 5.5 VESTOPLAST ® 888 9.0

Example 2: Preparing Multi Fiber Polymer Composites

[0071] For producing fiber polymer composites comprising several plies of the coated fabrics of example 1 (multi fiber polymer composites) a double belt press (DBP) type Reliant Powerbond-HPC, Reliant, Lukon, UK was used.

[0072] 4 plies of the coated fabrics were placed on each other (with the coated side upside) and an uncoated ply of fabric was placed on the top of the package. The pre-products were 1.5 m long. A piece of thin PTFE film was inserted in between the first and second coated fabric to help the ease separation of the first 60 mm section of the peel specimen before testing.

[0073] Some preliminary tests were performed in order to determine the suitable consolidation speed of the DBP. To attain uniform properties lengthwise, a pulling speed of 1.5 m/min and a pressure of 6 bar (6 bar being the maximum adjustable pressure value of the DBP) was used for all consolidation temperatures (120° C., 140° C., and 160° C.). At least 3 multi fiber polymer composites were produced with each of the matrices and each consolidation temperature.

[0074] At an elevated temperature, a relaxation phenomenon occurs in the highly oriented PP tapes (fabrics). This phenomenon not only deteriorates the reinforcing potential of the fibers, but reduces the length and the width of the fabric, and increases its thickness. Due to this effect, the areal density of the reinforcing fabric increases, which increases the fiber content of the composites. The extent of relaxation can be calculated with the initial area of the pre-products, and the area of the resulting composites after consolidation, with the following equation:

s=(1−(b.sub.2l.sub.2)/(b.sub.1l.sub.1)).Math.100,

where s (%) is the relaxation of the fabric, b.sub.1 and l.sub.1, are the initial width and length of the pre-products, respectively, and b.sub.2 and l.sub.2 are the width and length of the composites after consolidation, respectively. The relaxations of fabric 1 for all matrices and consolidation temperatures are shown in Table 3a.

TABLE-US-00004 TABLE 3a Relaxations of fabric 1 in the fiber polymer composites Consolidation Relaxation of Matrix material temperature [° C.] fabric [%] VESTOPLAST ® 708 120 5.3 VESTOPLAST ® 708 140 14.9 VESTOPLAST ® 708 160 38.6 VESTOPLAST ® 750 120 5.8 VESTOPLAST ® 750 140 15.3 VESTOPLAST ® 750 160 39.1 VESTOPLAST ® 792 120 4.3 VESTOPLAST ® 792 140 17.0 VESTOPLAST ® 792 160 37.6 VESTOPLAST ® 888 120 7.2 VESTOPLAST ® 888 140 14.1 VESTOPLAST ® 888 160 43.3

[0075] With the relaxation, the altered areal density can also be calculated with the following formula:

ρ.sub.A*=(1+s)*ρ.sub.A,

where ρ.sub.A*is the altered areal density of the fabric, s is the relaxation and ρ.sub.A is the initial areal density of the fabric.

[0076] The reinforcing fabric was wider than the matrix material coated on it. Consequently, the edges of the composite sheets did not contain enough matrix material to achieve a satisfactory level of consolidation, so the edges of the composites were removed using a manual sheet shearing machine. After measuring the length, the width and the weight of the composite sheets, the fiber content can be calculated using the following equation:

f=5b*l*ρ.sub.A*/m*100,

where f is the fiber content of the composite, b*and l*are the width and length of the composite sheet, respectively, ρA*is the altered areal density of the reinforcing fabric and m is the weight of the composite sheet. Table 3b contains the reinforcing fiber content of the fiber polymer composites obtained using fabric 1.

TABLE-US-00005 TABLE 3b Fiber content of the fiber polymer composites Consolidation Fiber content Matrix material temperature [° C.] [wt %] VESTOPLAST ® 708 120 79.8 VESTOPLAST ® 708 140 79.9 VESTOPLAST ® 708 160 75.5 VESTOPLAST ® 750 120 78.3 VESTOPLAST ® 750 140 79.5 VESTOPLAST ® 750 160 71.0 VESTOPLAST ® 792 120 72.6 VESTOPLAST ® 792 140 75.1 VESTOPLAST ® 792 160 72.6 VESTOPLAST ® 888 120 90.3 VESTOPLAST ® 888 140 87.0 VESTOPLAST ® 888 160 86.7

[0077] The consolidation/compaction of the fiber polymer composites obtained in example 2 was assessed by density measurement, peel test and microscopy. It was found that the density is unaffected by the matrix type but increased slightly with increasing consolidation temperature (for more details see example 4).

Example 3: Preparing Multi Fiber Polymer Composites from Fabric 2

[0078] Examples 1 and 2 were repeated using fabric 2 with VESTOPLAST® 708 and 792 respectively as matrix materials at a consolidation temperature of 120° C. All other steps and parameters were the same as already presented for fabric 1 in examples 1 and 2.

Example 4: Testing of the Fiber Polymer Composites and Results

[0079] Test examples were cut from the fiber polymer composites obtained in example 2 and 3 using a manual sheet shearing machine.

[0080] Since there is somewhat a difference between the fiber contents of the fiber polymer composite samples, the mechanical test results were normalized to 75 wt % by multiplying the determined test values by the ratio of (75%)/(determined reinforcing content).

Density: The density of the fiber polymer composite samples was evaluated in absolute ethanol at 23° C., according to EN ISO 1183-1. The results are given in table 4a below.

Interlaminar Peel Strength:

[0081] The interlaminar (peel) strength of the fiber polymer composite samples was determined on 25 mm×300 mm rectangular specimens with a Zwick Z020 (load cell 20 kN) universal testing machine at a crosshead speed of 152 mm/min by peeling off the side reinforcing and matrix layers of the composite sheets. Although the standard suggests to use a special peeling device which can be mounted on the crosshead of the tensile testing machine, due to the relatively low modulus of the composites, the specimens were fixed directly in the grips of the tensile testing machine. Consequently, the results of the peel test cannot be compared to the interlaminar strengths of other kinds of fabric-reinforced composites. Nevertheless, the effect of the matrix material and the consolidation temperature on the interlaminar strength of the VESTOPLAST® based composites can be investigated based on the results of the conducted peel tests. To initiate peeling, we inserted a small piece of polytetrafluoroethylene film between the first and second coated fabric during the assembly of the layers (for details see example 2). The values for Peel Strength obtained by this test are given in table 4a below

Static Tensile:

[0082] Static tensile tests were performed on rectangular specimens of 25 mm×200 mm (width×length) of the fiber polymer composite samples with a Zwick Z250 (load cell 20 kN) universal testing machine at a crosshead speed of 5 mm/min. The results of the static tensile tests, e.g. Tensile Strength and Young Modulus are given in table 4a below.

TABLE-US-00006 TABLE 4a Density, tensile strength and young modulus of the fiber polymer composites MM CT D PS TS-40 TS23 TS80 YM-40 YM23 YM80 V 708 120 0.714 0.36 95.1 47.4 18.5 1333 610 175 V 708 140 0.710 0.20 93.9 42.2 13.1 1003 492 147 V 708 160 0.722 0.10 60.7 28.8 10.4 1355 340 83 V 750 120 0.703 1.08 95.2 53.9 14.2 853 530 129 V 750 140 0.680 0.72 85.8 65.4 11.5 1103 355 111 V 750 160 0.776 1.13 84.1 43.9 11.1 1058 326 80 V 792 120 0.743 1.65 96.2 62.6 16.6 1328 443 140 V 792 140 0.772 1.45 89.5 74.5 9.9 1224 476 98 V 792 160 0.791 1.96 78.5 57.4 11.2 1245 368 104 V 888 120 0.751 0.16 79.4 42.3 13.3 895 496 134 V 888 140 0.714 0.20 71.1 38.2 10.8 758 285 99 V 888 160 0.807 0.63 61.7 29.2 8.1 798 241 62 MM: matrix Material; V: VESTOPLAST ®; CT: Consolidation Temperature given in ° C.; D: Density given in g/cm.sup.3; PS: Peel Strength given in N/mm; TS-40: Tensile Strength tested at −40° C. given in MPa; TS23: Tensile Strength tested at 23° C. given in MPa; TS80: Tensile Strength tested at 80° C. given in MPa; YM-40: Young Modulus tested at −40° C. given in MPa; YM23: Young Modulus tested at 23° C. given in MPa; YM80: Young Modulus tested at 80° C. given in MPa.

[0083] From the results in table 4a it can be seen, that the peel strength of fiber polymer composites increased with increasing molecular weight (Mw) of the matrix material VESTOPLAST® (from type 708 to 792) and therefore the interaction between the layers improved significantly. VESTOPLAST® 888 proved moderate peel strength values. Higher consolidation temperatures resulted in only a small improvement—especially for larger Mw samples (VESTOPLAST® 792, 888).

[0084] The tensile test results show, there is a small improvement in tensile strength for fiber polymer composites consolidated at 140° C. compared to 120° C., tested at room temperature. In the case of the consolidation temperature of 160° C., a huge decrement occurred. When they were tested at 80° C. there was no big difference either for consolidation temperature or matrix type.

Instrumented Falling Weight Impact

[0085] Instrumented falling weight impact (IFWI) tests were performed on a Fractovis 6785 device (Ceast, Pianezza, Italy) with the following settings: maximal energy: 593.4 J; diameter of the dart: 20 mm; diameter of the support ring: 40 mm; weight of the dart: 60.5 kg and drop height: 1 m. The IFWI test was conducted on 110 mm×110 mm square specimens of the fiber polymer composite samples in the case of fabric 1., and 150 mm×150 mm square specimens were used in the case of composites made of fabric 2. The test was also performed using a dart with a diameter of 15.9 mm on VESTOPLAST® 792-based composites at 23° C., in order to reveal the effect of the dart diameter on the perforation energy of the composites. The perforation energy was calculated from the total energy dissipated divided by the thickness of the test samples. The results are given in tables 4b and 4c below.

TABLE-US-00007 TABLE 4b Perforation energies of the fiber polymer composites MM CT PE-40 PE23 PE80 V 708 120 35.6 31.6 59.2 V 708 140 31.6 25.8 57.6 V 708 160 17.7 18.6 20.6 V 750 120 46.0 30.3 58.1 V 750 140 32.7 26.8 62.8 V 750 160 16.4 17.3 15.4 V 792 120 34.8 24.8 67.8 V 792 140 22.7 25.1 55.9 V 792 160 18.9 18.7 18.7 V 888 120 41.3 55.1 49.1 V 888 140 34.3 39.5 65.4 V 888 160 16.0 16.9 17.1 MM: matrix Material; V: VESTOPLAST ®; CT: Consolidation Temperature given in ° C.; PE-40: Perforation Energy tested at −40° C. given in J/mm; PE23: Perforation Energy tested at 23° C. given in J/mm; PE80: Perforation Energy tested at 80° C. given in J/mm;

[0086] It can be seen from the results given in table 4b that there is only vanishing difference between the VESTOPLAST® 700 series-based fiber polymer composites but VESTOPLAST® 888 exhibited higher perforation energy at room temperature, especially composites consolidated at 120 and 140° C., probably due to the poorer consolidation. Increasing consolidation temperature improved consolidation and the matrix/reinforcement interaction, and thereby decreased the damping capability of the fiber polymer composites.

[0087] The perforation energy of the composites consolidated at 120 and 140° C., tested at −40° C. and +80° C., was higher than the results of composites tested at room temperature.

[0088] VESTOPLAST® 888 itself possess an unexpectedly high perforation energy value at −40° C., so in the case of VESTOPLAST® 888 the test was also performed at −60° C. At −60° C. VESTOPLAST® 888 behaves similarly to the other investigated VESTOPLAST grades at −40° C. The different behaviour of VESTOPLAST® 888 at lower temperatures can be attributed to the lower glass transition temperature (T.sub.g) of VESTOPLAST® 888.

[0089] The failed IFWI specimens were analysed by sight. The failure behavior at lower temperatures was tape fracture and matrix deformation with moderate delamination but at higher testing temperatures significant wrinkling and creasing also occurred.

TABLE-US-00008 TABLE 4c Effect of dart diameter on perforation energy values of the fiber polymer composites MM CT PE23-15.9 PE23-20 V 792 120 16.6 24.8 V 792 140 13.5 25.1 V 792 160 13.3 18.7 MM: matrix Material; V: VESTOPLAST ®; CT: Consolidation Temperature given in ° C.; PE-23-15.9: Perforation Energy tested at 23° C. with a dart having a diameter of 15.9 mm given in J/mm; PE-23-20: Perforation Energy tested at 23° C. with a dart having a diameter of 20 mm given in J/mm.

[0090] It can be seen from the results in table 4c that the perforation energy is higher in the case of the dart with a diameter of 20 mm.

[0091] The IFWI tests were also performed with samples obtained in example 4 (based on fabric 2). The size of the samples was increased from 110×110 mm to 150×150 mm in order to ensure better gripping by the clamping unit of the falling weight impact tester. The results are given in Table 5.

TABLE-US-00009 TABLE 5 Perforation Energy of the fiber polymer composites of example 3 MM CT PE-40 PE23 PE80 V 708 120 29 167 180 V 792 120 59 193 300 MM: matrix Material; V: VESTOPLAST ®; CT: Consolidation Temperature given in ° C.; PE-40: Perforation Energy tested at −40° C. given in J/mm; PE23: Perforation Energy tested at 23° C. given in J/mm; PE80: Perforation Energy tested at 80° C. given in J/mm;

[0092] Testing at 80° C. causes significant softening of both matrix and reinforcement, therefore the clamping force of the instruments were not enough to keep the specimens in the right position, so the dart creased the specimens in the support ring. Thereby the values determined at 80° C. are only informative.

[0093] Comparing the results given in tables 4b and 5 it becomes clear, that the impact energy absorption capability can be further improved significantly by using a stronger fabric, as for example fabric 2, a woven fabric of high-tenacity PP multifilament.

Morphology

[0094] The morphology of the fiber polymer composites was studied with a scanning electron microscope (SEM) and with a light microscope (LM).

[0095] SEM images of the surface of the peel samples were taken with a Jeol JSM 6380 LA scanning electron microscope (Jeol Ltd., Tokyo, Japan). Before SEM, the surfaces of the test samples were sputter-coated with gold.

[0096] Light microscopy images of cut cross-sections prepared by cryogenic microtome at −50° C. were taken with an Olympus BX51M light microscope (Olympus, Hamburg, Germany).

[0097] Some of the samples produced in example 2 were peeled and examined using a scanning electronic microscope (SEM). The SEM images showed, that the matrix of the composites consolidated at 120° C. showed some delamination; the surface of the tapes remained generally intact. For the VESTOPLAST® 888 based composites, tape/matrix interaction was poor. For the fiber polymer composites consolidated at 160° C., some fibrillation of the tapes and much better tape/matrix adhesion can also be observed.

[0098] The samples produced in example 2 were examined using a light microscope. The main difference between the samples consolidated at different temperatures is that the composites kept their laminated structure at 120° C. but deformed at 160° C. The structures consolidated at 140° C. are similar to those of the fiber polymer composites consolidated at 120° C. The destruction of the structure is probably caused by the high temperature, high pressure and intensive relaxation.

Example 5: Comparison with Other Fiber Polymer Composites

[0099] Perforation energy and tensile strength values were determined using the test methods as mentioned above for different fiber polymer composites known in the art and/or commercially available. The results are given in tables 6a and 6b below.

TABLE-US-00010 TABLE 6a Comparison of the perforation energy of the fiber polymer composites according to the present invention with known and/or commercially available fiber polymer composites MM/FPC CT PE23 V 792, fabric 1 120 34.8 V 792, fabric 2 120 193.1* CURV ® [1] 24.8 PURE ® [2] 23.4 Self-reinforced PP, hot compacted 21.5 at 188° C. [3] Self-reinforced PP with added PP films, 22.0 hot compacted at 188° C. [4] Self-reinforced PP, film-stacking at 15.1 165° C. [5] Self-reinforced PP with beta-PP as matrix, 18.0 film-stacking at 156° C. [6] MM: matrix Material; FPC: fiber polymer composite; V: VESTOPLAST ®; CT: Consolidation Temperature given in ° C.; PE23: Perforation Energy tested at 23° C. given in J/mm. *in the case of fabric 2, although the specimens were perforated, they were also severely deformed, as the clamping force was not enough to keep the specimens in the right position during the test. A significant portion of the high perforation energy was caused by this undesirable deformation. Nevertheless, it is certain that the composites prepared with fabric 2 have bigger perforation energy values due to the higher strength and tenacity of fabric 2, but the correct value is somewhat lower.

TABLE-US-00011 TABLE 6b Comparison of the tensile strength of the fiber polymer composites according to the present invention with known and/or commercially available fiber polymer composites MM/FPC CT TS23 V 792, fabric 1 120 63 V 792, fabric 2 120 99 CURV ® [1] 152 PURE ® [2] 200 Self-reinforced PP, hot compacted 138 at 188° C. [3] Self-reinforced PP with added PP films, 150 hot compacted at 188° C. [4] Self-reinforced PP, film-stacking at 125 165° C. [5] Self-reinforced PP with beta-PP as matrix, 91 film-stacking at 156° C. [6] MM: matrix Material; FPC: fiber polymer composite; V: VESTOPLAST ®; CT: Consolidation Temperature given in ° C.; TS23: Tensile Strength tested at 23° C. given in MPa.

[0100] More details to the fiber polymer composites not according to the invention can be found at the following references: [0101] [1] www.curvonline.com (2019.06.08.) [0102] [2] www.ditweaving.com (2019.06.10.) [0103] [3] Swolfs Y., Van den Fonteyne W., Baets J., Verpoest I.: Failure behavior of self-reinforced polypropylene at and below room temperature. Applied Science and Manufacturing, 65, 100-107 (2014). [0104] [4] Swolfs Y., Zhang Q., Baets J., Verpoest I.: The influence of process parameters on the properties of hot compacted self-reinforced polypropylene composites. Composites Part A: Applied Science and Manufacturing, 65, 38-46 (2014). [0105] [5] Bárány T., Izer A., Czigány T.: High performance self-reinforced polypropylene Composites. Materials Science Forum, 537, 121-128 (2007). [0106] [6] Bárány T., Izer A., Karger-Kocsis J.: Impact resistance of all-polypropylene composites composed of alpha and beta modifications. Polymer Testing, 28, 176-182 (2009).

[0107] From the results given in table 6a it becomes clear that fiber polymer composites according to the present invention show much higher penetration energy values than those known in the art. The fiber polymer composites according to the present invention are therefore much more stable regarding penetration by for example bullets or arrows and can therefore be better used to produce bullet proof or safety clothes.

[0108] From the results given in table 6b it becomes clear that fiber polymer composites according to the present invention show lower tensile strength values than those known in the art and therefore are less brittle.

[0109] The examples show, that fiber polymer composites based on propylene rich APAO matrix material possess good mechanical properties and excellent mechanical energy damping properties. From the examples it becomes clear, that especially the propylene rich APAOs VESTOPLAST® 792 and 750 show excellent mechanical and mechanical energy damping properties. It becomes clear from the examples that processing (Consolidation/compaction) temperatures of from 120 and 140° C. are sufficient to obtain useful fiber polymer composites. This temperature range is well below the temperature used for processing other (all-)polypropylene composites known in the art. This way, energy is saved and the reinforcement is processed more gently (with less heat).