HYBRID FABRICS OF HIGH PERFORMANCE POLYETHYLENE FIBER

Abstract

The invention relates to hybrid fabric comprising: a high-performance polyethylene (HPPE) fiber having a tensile modulus of at least 110 GPa, preferably higher than 135 GPa, as measured according to ASTM D885M-2014; and a non-polymeric fiber, wherein the cross-sectional area of the HPPE fiber is equal to or smaller than the cross-sectional area of the non-polymeric fiber, the cross-sectional area being defined as the linear density of the fiber divided by volumetric density of the fiber. The invention also relates to a composite comprising the hybrid fabric and to an article comprising the composite.

Claims

1. A hybrid fabric comprising: i) a high-performance polyethylene (HPPE) fiber arranged in a yarn having a tensile modulus of at least 110 GPa, as measured according to ASTM D885M-2014; and ii) a non-polymeric fiber arranged in a yarn, wherein the cross-sectional area of the HPPE yarn is equal to or smaller than the cross-sectional area of the non-polymeric yarn, the cross-sectional area being defined as the linear density of the yarn divided by volumetric density of the fiber.

2. The hybrid fabric according to claim 1, wherein the high-performance polyethylene (HPPE) fiber has a tensile modulus of at least 120 GPa, preferably of at least 130 GPa, more preferably of higher than 135 GPa.

3. The hybrid fabric according to claim 1, wherein the high-performance polyethylene (HPPE) fiber has a tensile modulus of at least 140 GPa, preferably of at least 145 GPa, more preferably of at least 150 GPa, most preferably of at least 155 GPa.

4. The hybrid fabric according to claim 1, wherein the non-polymeric fibers are selected from a group consisting of carbon fibers, glass fibers, wollastonite fibers, basalt fibers and/or mixtures thereof.

5. The hybrid fabric according to claim 1, wherein the fabric is knitted, plaited, braided or a combination thereof, preferably the fabric is a woven fabric.

6. The hybrid fabric according to claim 1, wherein the HPPE fiber is prepared by a melt spinning process, a gel spinning process or solid-state powder compaction process.

7. The hybrid fabric according to claim 1, wherein the HPPE fiber has a tenacity of at least 2 N/tex, preferably of at least 3 N/tex, more preferably at least 3.5 N/tex, as measured at yarn level.

8. The hybrid fabric according to claim 1, wherein the HPPE fiber comprises ultra-high molecular weight polyethylene (UHMWPE), preferably the HPPE fibers are UHMWPE fibers.

9. The hybrid fabric according to claim 1, further comprising a matrix material.

10. The hybrid fabric according to claim 1 comprising of from 15 to 45 vol %, preferably from 15 to 35 vol % HPPE fiber relative to the total volume of the matrix free hybrid fabric.

11. A composite comprising at least one layer of the hybrid fabric according to claim 1.

12. The composite according to claim 11, further comprising at least one layer of other fabric comprising of from 100 to 80 vol % non-polymeric fibers and from 0 to 20 vol % HPPE fibers, based on the total volume of the other fabric.

13. An article comprising the composite according to claim 11, the article being selected from wheel rim for cars, bicycles and motorcycles, interiors for cars, impact panels, aircrafts, satellites, bicycles frames, cockpits, seats, hockey sticks, baseball bats, tennis and squash rackets, ski and snowboards, surfboards, paddle boards, helmets such as for cycling, football, climbing, motorsport, boat hulls, masts, sails, boats, wind turbines and tidal turbines.

14. Use of the article according to claim 13 in automotive field, preferably in wheel rims for cars and motorcycles, interiors for cars, impact panels; in aerospace field, preferably in aircrafts and satellites; in sports equipment, preferably in bicycles, bicycles frames, cockpits, seats, hockey sticks, baseball bats, tennis and squash rackets, ski and snowboards, surfboards, paddle boards, helmets such as for cycling, football, climbing, motorsport; in marine field, preferably in boat hulls, masts, sails, boats; in military field; and in wind and renewable energy field, preferably in wind turbines and tidal turbines.

Description

EXAMPLES

Methods

[0061] Tex: yarn's or filament's titer was measured by weighing 100 meters of yarn or filament, respectively. The tex of the yarn or filament was calculated by dividing the weight (expressed in milligrams) by 100. [0062] IV: the Intrinsic Viscosity is determined according to method ASTM D1601 (2004) at 135° C. in decalin, the dissolution time being 16 hours, with BHT (Butylated Hydroxy Toluene) as anti-oxidant in an amount of 2 g/I solution, by extrapolating the viscosity as measured at different concentrations to zero concentration. [0063] Tensile properties of HPPE fibers: tensile strength (or strength) and tensile modulus (or modulus) are defined and determined on multifilament yarns as specified in ASTM D885M (2014), using a nominal gauge length of the fiber of 500 mm, a crosshead speed of 50%/min and Instron 2714 clamps, of type “Fiber Grip D5618C”. On the basis of the measured stress-strain curve the modulus is determined as the gradient between 0.3 and 1% strain. For calculation of the modulus and strength, the tensile forces measured are divided by the titre, as determined above; values in GPa are calculated assuming a density of 0.975 g/cm.sup.3 for the HPPE. [0064] Tensile properties of fibers having a tape-like shape: tensile strength, tensile modulus and elongation at break are defined and determined at 25° C. on tapes of a width of 2 mm as specified in ASTM D882, using a nominal gauge length of the tape of 440 mm, a crosshead speed of 50 mm/min. [0065] Tensile modulus and tensile strength of the multilayer hybrid composite samples was measured according to standard method ISO 527/4 (2012) at room temperature, i.e. 25° C. Specimens with a width of 10±0.05 mm were machined from the panel in the warp direction of the fabrics. The thickness of the samples was measured at various places on the sample. Tabs of the same panel were glued to the ends to prevent clamp failure, using a high peel strength epoxy resin commercially available as Redux® 810 from Hexcel. Curing was done at room temperature. The gauge length of the samples was 25 mm. Test speed was 2 mm/min. Strains were measured with strain gauges. Tensile properties were measured on composite samples containing 6 layers of fabric. The tensile properties were scaled back to a normalized fiber volume fraction of 50%, by multiplying the measured value by the ratio of real fiber volume fraction and the normalized fiber volume fraction (e.g. Scaled modulus=measured modulus x real fiber volume fraction/normalized fiber volume fraction). In this scaling the contribution of the matrix is ignored. [0066] Volumetric density of the multilayer hybrid composite samples was measured in water according to standard method ISO 1183-1 2012. [0067] Areal Density (AD) of the fabrics was obtained by weighing a certain area of a sample and dividing the obtained mass by the area of the sample (kg/m.sup.2) and AD of the multilayer hybrid composite samples by multiplying the volumetric density of the composite by the thickness of the multilayer composite. [0068] Impact strength (Fmax, puncture resistance and Energy to Fmax) of the multilayer hybrid composite samples were measured according to standard method ISO 6603-2 (2000) at room temperature, i.e. about 23° C. on a 10×10 cm.sup.2 rectangular multilayer hybrid composite panel of thickness t, clamped using a ring with diameter 40 mm. Below the panel was placed an airgap. A hemispherical dart with 20 mm radius and mass m=23.67 kg was used to test the penetration resistance by varying the initial height h=1 m. Each plate was tested by 3 impacts with varying initial height h to generate penetrations and stops. Impact properties were measured on composite samples containing 6 layers of fabric.

Fabric A (Comparative)

[0069] A plain single layer woven fabric A was produced from warp yarns and weft yarns in a 2/2 twill arrangement and 6.0 threads per cm of 100 vol % carbon fibers, based on the total fabric A composition, the carbon fibers being commercially available under the tradename Toray T300-3K from Toray, the fibers (or the yarn) having a linear density of 2000 dtex. AD of the fabric A was 245 g/m.sup.2.

Fabric B

[0070] A plain single hybrid woven fabric was produced from warp yarns and weft yarns in a 2/2 twill arrangement and 6.0 threads per cm. The fabric consists of 28 vol % UHMWPE fiber commercially available as Dyneema® SK99 (that is a yarn having a linear density of 880 dtex, a tenacity of 4.3 N/tex and a tensile modulus of 155 GPa, a volumetric density of the yarn or fiber of 975 kg/m′, such that cross-sectional area of the yarn was 0.09 mm.sup.2) and 72 vol % carbon fibers commercially available as Toray T300-3K (that is a yarn having a linear density of 2000 dtex, a tensile modulus of 230 GPa, a volumetric density of the yarn or fiber of 1760 kg/m′, such that cross-sectional area of the yarnwas 0.113 mm.sup.2), the vol % being based on the total fabric B composition. The weft and the warp yarns comprise Dyneema® SK99 fibers and carbon fibers in a yarn ratio of 1:2 in the woven fabric B. AD of the fabric B was 192 g/m.sup.2.

Fabric C (Comparative)

[0071] A plain single hybrid woven fabric was produced from warp yarns and weft yarns in a 2/2 twill arrangement and 6.7 threads per cm. The fabric consists of 45 vol % UHMWPE fiber commercially available as Dyneema® SK75 (that is a yarn having a linear density of 1760 dtex, a tenacity of 3.5 N/tex and a tensile modulus of 135 GPa, a volumetric density of the yarn or fiber of 975 kg/m.sup.3, such that the cross-sectional area of the yarn was 0.18 mm.sup.2) and 55 vol % carbon fibers commercially available as Pyrofil TR30S-3K (that is a yarn having a linear density of 2000 dtex, a tensile modulus of 235 GPa, a volumetric density of the yarn of fiber of 1790 kg/m.sup.3, such that cross-sectional area of the yarn was 0.11 mm.sup.2), the vol % being based on the total fabric C composition. The weft and the warp yarns comprise Dyneema® SK75 fibers and carbon fibers in a yarn ratio of 1:2 in the woven fabric C. AD of the fabric C was 250 g/m.sup.2.

Fabric D (Comparative)

[0072] A plain single hybrid woven fabric was produced from warp yarns and weft yarns in a 2/2 twill arrangement and 6.0 threads per cm. The fabric consists of 28 vol % UHMWPE fiber commercially available as Dyneema® SK99 (that is a yarn having a linear density of 1760 dtex, a tenacity of 4.3 N/tex and a tensile modulus of 155 GPa, a volumetric density of the yarn or fiber of 975 kg/m.sup.3, such that cross-sectional area of the yarn was 0.18 mm.sup.2) and 72 vol % carbon fibers commercially available as Toray T300-3K (that is a yarn having a linear density of 2000 dtex, a tensile modulus of 230 GPa, a volumetric density of the yarn or fiber of 1760 kg/m′, such that cross-sectional area of the yarn was 0.113 mm.sup.2), the vol % being based on the total fabric D composition. The weft and the warp yarns comprise Dyneema® SK99 fibers and carbon fibers in a yarn ratio of 1:4 in the woven fabric D. AD of the fabric D was around 235 g/m.sup.2.

Fabric E (Example)

[0073] A plain single hybrid woven fabric was produced from warp yarns and weft yarns in a 2/2 twill arrangement and 6.0 threads per cm. The fabric consists of 28 vol % UHMWPE fiber commercially available as Dyneema® SK75 (that is a yarn having a linear density of 880 dtex, a tenacity of 3.5 N/tex and a tensile modulus of 135 GPa, a volumetric density of the yarn or fiber of 975 kg/m′, such that cross-sectional area of the yarn was 0.09 mm.sup.2) and 72 vol % carbon fibers commercially available as Toray T300-3K (that is a yarn having a linear density of 2000 dtex, a tensile modulus of 230 GPa, a volumetric density of the yarn or fiber of 1760 kg/m.sup.3, such that cross-sectional area of the yarn was 0.113 mm.sup.2), the vol % being based on the total fabric E composition. The weft and the warp yarns comprise Dyneema® SK75 fibers and carbon fibers in a yarn ratio of 1:2 in the woven fabric E. AD of the fabric E was 192 g/m.sup.2.

[0074] The fabrics A-E obtained as shown herein above were then each cut on size and stacked in different multilayer hybrid constructions as shown in the Examples and Comparative Examples herein below. All layers in the stack were aligned along warp and weft direction. Each stack of layers was put in a vacuum plastic bag that had an inlet and an outlet, in order to remove all the air from the stack and then placed on an infusion table for subsequent impregnation with a resin. A flow medium (commercially available as Compoflex RF150 purchased from Fibertex that is a fabric based on polypropylene that helps the resin flowing through the stack) was added to the vacuum bag, as well as spiral tubes for both inlet and outlet of the vacuum bag were placed to seal the infusion table. The infusion table was then left for 30 min at room temperature to degas under vacuum and to remove the moisture from the fabrics.

[0075] A mixture of an epoxy resin that is known under the commercial name EPIKOTE resin 04908/1 with EPIKURE Curing Agent 04908 commercially available from Hexion was employed as the resin matrix. Before infusion, the resin was degassed in a vacuum chamber to remove all air. The impregnation process of the stack of layers with the resin took place at a temperature of 40° C. and an absolute pressure of 0.01 bar (vacuum). After full saturation of the fabrics (meaning that each layer of the stack was impregnated with the resin in such a way that the stack contained no voids), the inlet of the bag was closed and the infusion table was heated to a temperature of 70° C. Then, polyurethane plates were placed on top of the table to cover the stack. The multilayer hybrid composites so formed were left to cure for 16 hours at a temperature of 70° C.

Example 1

[0076] A multilayer hybrid composite was formed by stacking layers comprising fabrics B and then impregnating the stack obtained as described herein above and then forming a multilayer hybrid composite. The composition of the multilayer hybrid composite obtained was 54 vol % resin, 46 vol % of total volume of fabric B, 13 vol % UHMWPE fibers and 33 vol % carbon fibers, each based on the total volume of the multilayer hybrid composite. The results are reported in Table 1.

Comparative Experiment 1 (CE1)

[0077] A multilayer hybrid composite was formed by stacking layers comprising fabric A and then impregnating the stack obtained as described herein above and then forming a multilayer hybrid composite. The composition of the multilayer hybrid composite obtained was 50 vol % carbon fibers and 50 vol % resin, each based on the total volume of the multilayer hybrid composite. The results are reported in Table 1.

Comparative Experiment 2 (CE2)

[0078] A multilayer hybrid composite was formed by stacking layers comprising fabric C and then impregnating the stack obtained as described herein above and then forming a multilayer hybrid composite. The composition of the multilayer hybrid composite obtained was 45 vol % resin, 55 vol % of total volume of fabric C, 24.8 vol % UHMWPE fibers and 30.7 vol % carbon fibers, each based on the total volume of the multilayer hybrid composite. The results are reported in Table 1.

Comparative Experiment 3 (CE3)

[0079] A multilayer hybrid composite was formed by stacking layers comprising fabric D and then impregnating the stack obtained as described herein above and then forming a multilayer hybrid composite. The composition of the multilayer hybrid composite obtained was 50 vol % resin, 50 vol % of total volume of fabric B, 14 vol % UHMWPE fibers and 36 vol % carbon fibers, each based on the total volume of the multilayer hybrid composite. The results are reported in Table 1.

Example 2 (Ex. 2)

[0080] A multilayer hybrid composite was formed by stacking layers comprising fabric E and then impregnating the stack obtained as described herein above and then forming a multilayer hybrid composite. The composition of the multilayer hybrid composite obtained was 48 vol % resin, 52 vol % of total volume of fabric B, 14.5 vol % UHMWPE fibers and 38.5 vol % carbon fibers, each based on the total volume of the multilayer hybrid composite. The results are reported in Table 1.

TABLE-US-00001 TABLE 1 Sample CE1 CE2 CE3 Ex. 2 Ex. 1 Length sample, mm 600 600 400 400 500 Width sample, mm 500 500 400 400 500 Composite panel thickness 1.67 2.09 1.86 1.45 1.69 6 layers, mm Composite AD for 6 layer 2450 2715 2500 1980 2264 panel, g/m.sup.2 Composite volumetric 1.47 1.31 1.34 1.36 1.34 density, g/cm.sup.3 Fiber volume fraction, % 50 55 50 52 46 UHMWPE fiber in total 0 24.8 14 14.5 13 composite composition, vol % Tensile modulus, GPa 57.1 40.7 39.8 42.2 46 Tensile strength, MPa 878 447 453 475 518 Scaled Tensile Modulus 57.1 37.0 39.8 40.6 50.0 to 50% Fiber Vol, GPa Scaled Tensile Strength 878 406 453 457 563 to 50% Fiber Vol, MPa Fmax upon impact, N 2054 2387 4650 3158 2743 Energy to Fmax, J 5.69 4.95 9.67 4.86 6.41 Puncture energy, J 9.87 11.4 18.04 13.56 17.25 Fmax/AD 0.84 0.88 1.86 1.59 1.21 Energy to Fmax/AD 0.0023 0.0018 0.0039 0.0025 0.0028 Puncture energy/AD 0.0040 0.0042 0.0072 0.0068 0.0076

[0081] The results presented in Table 1 show that the multilayer hybrid composites obtained with the hybrid fabric according to the present invention (Example 1 and Example 2) show the best balance of good structural stiffness, strength and good impact performance. On the other hand, the Comparative Examples show poor impact strength (Comparative Example 1) and low structural properties (tensile strength, and tensile modulus of Comparative Examples 2 and 3).