Fibersizing with small amounts of nanomaterials

Abstract

Nanoparticle-coated fibre material, the coating of which includes between 0.01 and less than 2.0 wt % of nanoparticles based on the dry weight of the coated fibre material and is capable of undergoing further reactions, a process for producing the nanoparticle-coated fibre materials, and also corresponding fibre composite materials.

Claims

1. A nanoparticle-coated fibre material, comprising a fibre material and a coating on at least a portion of the fibre material, wherein: the coating comprises from 0.01 wt % to less than 0.4 wt % of nanoparticles based on a dry weight of the nanoparticle-coated fibre material; the coating is capable of undergoing further reactions; and the nanoparticles comprise surface-modified spherical silica nanoparticles.

2. The fibre material according to claim 1, wherein the fibre material comprises a glass fibre material.

3. The fibre material according to claim 1, wherein the coating further comprises crosslinkable epoxy groups capable of undergoing the further reactions.

4. The fibre material according to claim 1, wherein the coating further comprises an epoxy resin.

5. A process for producing a nanoparticle-coated fibre material, the process comprising: contacting a fibre material with an aqueous emulsion comprising a film-former by dipping, spraying or bathing the fibre material with the aqueous emulsion, to obtain a coated fibre material; and then drying the coated fibre material, to obtain a nanoparticle-coated fibre material, wherein: the aqueous emulsion further comprises surface-modified spherical silica nanoparticles; and the coating of the nanoparticle-coated fibre material comprises from 0.01 wt % to less than 0.4 wt % of nanoparticles based on a dry weight of the coated fibre material.

6. A process for producing a nanoparticle-coated fibre material, the process comprising: contacting a fibre material with an aqueous emulsion comprising a film-former, to obtain a coated fibre material; and then drying the coated fibre material, to obtain a nanoparticle-coated fibre material, wherein: the aqueous emulsion further comprises surface-modified spherical silica nanoparticles; the coating of the nanoparticle-coated fibre material comprises from 0.01 wt % to less than 0.4 wt % of nanoparticles based on a dry weight of the coated fibre material; and the contacting occurs by applying the aqueous emulsion to the fibre material with a rotating applicator roll, such that the contacting does not occur by directly dipping the fibre material into a bath of the aqueous emulsion.

7. The process according to claim 5, wherein the aqueous emulsion comprises from 1 to 50 wt % of the surface-modified spherical nanoparticles based on a solids content of the aqueous emulsion.

8. A fibre composite material, comprising the nanoparticle-coated fibre material of claim 1.

9. The fibre composite material according to claim 8, comprising the nanoparticle-coated fibre material in a polymer matrix.

10. The fibre composite material according to claim 9, wherein the polymer matrix is a thermoset polymer matrix.

11. The fibre composite material according to claim 10, wherein the thermoset polymer matrix is an epoxy resin.

12. The process according to claim 6, wherein the aqueous emulsion comprises from 1 to 50 wt % of the surface-modified spherical nanoparticles based on a solids content of the aqueous emulsion.

Description

EXAMPLES

(1) Materials:

(2) Nanopox F 400 (trade mark of Evonik Hanse GmbH, Germany) contains 40 wt % of SiO.sub.2 particles having a (number average) diameter of 20 nm and was first emulsified with water. This aqueous emulsion was subsequently diluted to the values reported in the examples.

(3) Neoxil 965 (DSM Composite Resins) was always employed as a 4 wt % emulsion in water based on the overall emulsion.

(4) Desizing of Fibre Materials:

(5) A fibre bundle is led past an IR radiator at a distance of 2 cm. The speed was optimized to ensure complete removal of the original sizing. This was determined via the loss of mass.

(6) General Coating Process:

(7) A rotating applicator roll applies the film-former atop the fibre material. The applicator roll dips with its bottom side into the sizing bath, picks up a certain amount of film-former as it rotates, and the fibre material is contacted with the film-former on the top side of the roll. The speeds of the roll and of the fibre material are aligned such that there is no speed difference.

Example 1, Sizing Desized Glass Fibres

(8) The glass fibre material StarRov086 (trade mark of Johns Manville, USA), of the PR 220 1200 086 variant, was desized by IR irradiation, cooled down to room temperature and weighed. The fibre bundles were coated directly thereafter. The dip bath contained an aqueous emulsion of epoxy resin film-formers with or without SiO.sub.2 nanoparticles. After dipping, the fibres were dried at 60 C. to constant weight. The sizing add-on was subsequently rechecked by differential weighing.

(9) The sizing materials were each applied at 1.8 wt % (based on the mass sum total of the fibres after cleaning+applied coating). Three sizing materials were tested.

(10) The dip baths had the following compositions: 1. Neoxil 965 only 2. Mixture of 50 wt % of Neoxil 965 and 50 wt % of Nanopox F 400 (as 2 wt % SiO.sub.2 aqueous emulsion) 3. Mixture of 50 wt % of Neoxil 965 and 50 wt % of Nanopox F 400 (as 5 wt % SiO.sub.2 aqueous emulsion).

(11) At constant weight, the coatings accordingly compute as follows:

(12) System 1: 1.8 wt % of Neoxil 965, not according to the present invention

(13) System 2: 1.2 wt % of Neoxil 965 and 0.6 wt % of Nanopox F 400, corresponding to 0.24 wt % of SiO.sub.2

(14) System 3: 0.8 wt % of Neoxil 965 and 1 wt % of Nanopox F 400, corresponding to 0.4 wt % of SiO.sub.2

(15) The coated fibre materials were then used to wind test specimens as UD materials. These were subsequently saturated with the epoxy resin/hardener mix and cured in accordance with the manufacturer's directions. The epoxy resin Infusion Resin MGS RIM 135 (trade mark of Hexion, Germany) was used in combination with the hardener RIMH 137 (Hexion). The impregnating method chosen was VARI (Vacuum Assisted Resin Infusion). The laminates thus obtained were tested in respect of their mechanical properties.

(16) The results are summarized in Table 1, 5 test specimens were measured in each case, the arithmetic means are reported:

(17) Fracture toughness was measured to DIN EN ISO 15024:2001 with the following parameters: 65 mm delamination strength.

(18) Transverse tensile strength was determined to DIN EN ISO 527-5:2008.

(19) Dissipated energy was determined to DIN EN ISO 13003:2003 in the three-point bending test after 3000 cycles.

(20) TABLE-US-00001 TABLE 1 Mechanical properties of laminates as per Example 1 Test System 1 System 2 System 3 Transverse tensile 16 mPas 22 mPas 16 mPas strength Fracture toughness G.sub.lc 419 J/m.sup.2 550 J/m.sup.2 n.d. Dissipated energy 4 Nmm 2.5 Nmm 2.4 Nmm

(21) Transverse tensile strength is distinctly improved for system 2, featuring a nanoparticle content of 0.24 wt % on the fibre (corresponding to 0.6 wt % of Nanopox F 400). Fracture toughness of the laminate also improves by more than 30% to 550 J/m.sup.2 in the case of system 2.

(22) The dissipated energy data provide evidence that the presence of nanoparticles on the fibre leads to a distinct improvement in fatigue behaviour.

Example 2, Sizing Glass Fibres Having Commercial Sizing as Substrate

(23) An industrial biaxial NCF having a basis weight of 807 g/m.sup.2 and a +45/45 orientation (Saertex) was used. What is concerned here is the glass fibre material Hybon 2001/2 600 tex (trade mark of PPG Fiber Glass, USA), which had an unknown epoxy sizing without nanomaterials.

(24) Repeated dipping into an aqueous emulsion of Nanopox F 400 and subsequent drying at 60 C. as described in Example 1 was used to produce two modified non-crimp fabrics with differing add-on. The non-crimp fabric as supplied (system A, comparator), with an additional 1.5 wt % (corresponding to 0.6 wt % of SiO.sub.2, system B) of Nanopox based on fabric weight and also with an additional 4 wt % of Nanopox (corresponding to 1.6 wt % of SiO.sub.2, system C) were then processed into a fibre composite material. To this end, a plied construction ([+45/45/0/90/45/+45/90/0])s was processed by VARI (Vacuum Assisted Resin Infusion) into sheets 5 mm in thickness. The resin/hardener system used was Epikote RIMR 135 and Epikure RIMH 137 as in Example 1.

(25) Interlaminar shear strength (ILSS), determined to ASTM-D 2344, was virtually identical for all three laminates at 47 MPa for system A (control), 45 MPa for system B and 49 MPa for system C. What improves conspicuously is the fracture toughness of the laminates, as determined to ASTM-D 5528, as shown in Table 2.

(26) TABLE-US-00002 TABLE 2 Mechanical properties of laminates as per Example 2 Test System A System B System C Fracture toughness G.sub.lc 950 J/m.sup.2 1780 J/m.sup.2 1920 J/m.sup.2

(27) An add-on of 0.6 wt % of SiO.sub.2 nanoparticles on the fabric improves fracture toughness by 86%. An add-on of 1.6 wt % of nanoparticles even yields an improvement by 102%.