Modified fibers for use in the formation of thermoplastic fiber-reinforced composite articles and process

Patent metadata

Field	Value
Publication number	US-9394199-B2
Application number	US-201213653573-A
Country	US
Kind code	B2
Filing date	Oct 17, 2012
Priority date	Dec 27, 2006
Publication date	Jul 19, 2016
Grant date	Jul 19, 2016

Abstract

A surface-modified fibrous material is provided for incorporation in a thermoplastic matrix to form a fiber-reinforced composite article. Good binding between the fibrous material and the thermoplastic matrix is achieved through the presence of finely roughened surfaces on the fibers of nanoparticles of an inorganic material. Such nanoparticles are provided from an alkaline aqueous size composition containing the nanoparticles dispersed therein (as described). The fibrous material may be provided in continuous or discontinuous form. In a preferred embodiment glass fibers are initially provided in continuous form followed by cutting into discontinuous lengths and drying with the retention of the nanoparticles on the surfaces of the fibers. The surface-roughened fibrous material is incorporated in a thermoplastic matrix as fibrous reinforcement with the application of heat whereby the thermoplastic matrix is rendered melt processable. In preferred embodiments injection or compression molding is utilized. Improved long-fiber thermoplastics also may be formed to advantage.

First claim

We claim:

1. A process for forming a fiber-reinforced thermoplastic composite article, the process comprising:
(a) applying as a coating to the surface of glass fibers an alkaline aqueous size composition comprising:
a dispersion of nanoparticles of an inorganic material,
a polymeric film-former, and
a combination of silanes comprising at least one reactive silane and at least one non-reactive silane,

wherein the nanoparticles are in a concentration of about 10 to 40 percent by weight based on the weight of total sizing solids in the size composition,
(b) drying said coating present on said glass fibers to aid in adherence of the nanoparticles onto said glass fibers and provide a roughened surface on said glass fibers,
(c) incorporating said glass fibers bearing said roughened surface in a thermoplastic matrix as fibrous reinforcement with the application of heat whereby said thermoplastic matrix is rendered melt processable, wherein the at least one reactive silane couples the glass fibers to the thermoplastic matrix, and
(d) forming a fiber-reinforced composite article with the reinforced thermoplastic matrix, wherein the composite comprises a Notched Izod impact strength that is greater than a composite formed without the nanoparticles.

2. The process according to claim 1 , wherein step (c) forms a long-fiber-reinforced thermoplastic composite article.

3. The process of claim 1 , wherein said fibrous material is in the form of a multifilamentary roving.

4. The process of claim 1 , wherein said alkaline aqueous size of composition possesses a pH of approximately 7.5 to 13.

5. The process of claim 1 , wherein said nanoparticles of an inorganic material possess an average particle size of approximately 3 to 40 nm.

6. The process of claim 1 , wherein said nanoparticles of an inorganic material possess an average particle size of approximately 3 to 10 nm.

7. The process of claim 1 , wherein said nanoparticles of an inorganic material are silica.

8. The process according to claim 1 , wherein the Notched Izod impact strength is about 6.5% greater than the composite formed without the nanoparticles.

9. The process according to claim 1 , wherein the Notched Izod impact strength is measured in a longitudinal direction and is about 10.8% greater than the composite formed without the nanoparticles.

10. The process according to claim 1 , wherein the Notched Izod impact strength is measured in a longitudinal direction and about 82.3% greater than the composite formed without the nanoparticles.

11. The process for forming a fiber-reinforced thermoplastic composite article according to claim 1 , wherein said nanoparticles of an inorganic material are selected from the group consisting of silica, clay, glass, metals, titanium dioxide, zinc oxide, barium oxide, cerium gadolinium oxide, iron ferrite, aluminum polyphosphate, nanodiamonds, and mixtures of the foregoing.

12. The process for forming a fiber-reinforced thermoplastic composite article according to claim 1 , wherein in step (a) the nanoparticles of said inorganic material are caused to adhere to said fibrous material by initially coating said alkaline aqueous size composition on the surfaces of said fibrous material followed by removal of volatile materials.

13. The process for forming a fiber-reinforced thermoplastic composite article according to claim 1 , wherein said thermoplastic matrix of step (c) comprises a thermoplastic selected from the group consisting of polyolefins, polyesters, polyamides, polycarbonates, polyethers, liquid crystal polymers, polyethersulfones, polyphenylene oxide, polyphenylene sulfide, polybenzimidazoles, thermoplastic polyurethanes, and blends of the foregoing.

14. The process for forming a fiber-reinforced thermoplastic composite article according to claim 1 , wherein said thermoplastic matrix comprises polypropylene.

15. The process according to claim 1 , wherein the polymeric film-former is present at a concentration of 20 to 85 percent by weight of the total solids of the alkaline aqueous size composition.

16. A process for forming a discontinuous glass fiber-reinforced thermoplastic composite article, the process comprising:
(a) adhering nanoparticles of an inorganic material that are dispersed in an alkaline aqueous size composition to the surfaces of glass fibers which are present in continuous form so as to provide finely roughened surfaces on said continuous glass fibers as the result of the presence of said nanoparticles of said inorganic material, said adhering conducted by drying, wherein the alkaline aqueous size composition comprises:
a combination of silanes that includes at least one reactive silane and at least one non-reactive silane, and
a polymeric film-former, wherein the polymeric film-former aids in adherence of the nanoparticles onto the glass fibers, and

wherein the nanoparticles are in a concentration of about 10 to 40 percent by weight based on the weight of total sizing solids in the size composition,
(b) cutting said continuous glass fibers into discontinuous lengths while retaining said roughened surfaces on said glass fibers as the result of the presence of said nanoparticles of said inorganic material,
(c) extruding the discontinuous glass fibers having said finely roughened surfaces together with a thermoplastic wherein the surface-attached nanoparticles of inorganic material serve to promote the secure bonding of the discontinuous glass fibers within said thermoplastic matrix to form a material suitable for molding and wherein the at least one reactive silane couples the discontinuous glass fibers to the thermoplastic matrix, and
(d) injection or compression molding said material suitable for molding to form a fiber-reinforced composite article which displays an enhanced mechanical property comprising a Notched Izod impact strength that is greater than a composite formed without the nanoparticles.

17. The process for forming a discontinuous glass fiber-reinforced thermoplastic composite article according to claim 16 , wherein said continuous glass fibers of step (a) are selected from the group consisting of E-glass, C-glass, A-glass, AR-glass, D-glass, R-glass, S-glass, and mixture of the foregoing, and possess a diameter of approximately 2 to 50 microns.

18. The process for forming a discontinuous glass fiber-reinforced thermoplastic composite article according to claim 16 , wherein said continuous glass fibers of step (a) are E-glass, and possess a diameter of approximately 7 to 30 microns.

19. The process for forming a discontinuous glass fiber-reinforced thermoplastic composite article according to claim 16 , wherein said alkaline aqueous size composition possesses a pH of approximately 8 to 11.

20. The process for forming a discontinuous glass fiber-reinforced thermoplastic composite article according to claim 16 , wherein said nanoparticles of an inorganic material possess an average particle size of approximately 3 to 40 nm.

21. The process for forming a discontinuous glass fiber-reinforced thermoplastic composite article according to claim 16 , wherein said nanoparticles of an inorganic material possess an average particle size of approximately 3 to 10 nm.

22. The process for forming a discontinuous glass fiber-reinforced thermoplastic composite article according to claim 16 , wherein said nanoparticles of an inorganic material are selected from the group consisting of silica, clay, glass, metals, titanium dioxide, zinc oxide, barium oxide, cerium gadol

Assignees

• Johns Manville

Inventors

• Asrar Jawed
• Burghardt Thomas

Classifications

• D06M23/08

  Processes in which the treating agent is applied in powder or granular form (adhesives for multi-layer textile fabrics D06M17/00) · CPC title

• D06M11/00

  Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising (D06M10/00 takes precedence) · CPC title

• C03C25/47

  containing particles, fibres or flakes, e.g. in a continuous phase · CPC title

• Y10T428/2938

  Coating on discrete and individual rods, strands or filaments · CPC title

• C03C25/42

  Coatings containing inorganic materials · CPC title