Fiber-reinforced composite articles made from fibers having coupling-initiator compounds and methods of making the articles

Patent metadata

Field	Value
Publication number	US-9452569-B2
Application number	US-201414476481-A
Country	US
Kind code	B2
Filing date	Sep 3, 2014
Priority date	Jan 8, 2008
Publication date	Sep 27, 2016
Grant date	Sep 27, 2016

Abstract

Methods of making a fiber-reinforced composite article are described. The methods may include providing fibers to an article template, where the fibers have been treated with a coupling-initiator compound. They may further include providing a pre-polymerized mixture that includes a monomer and a catalyst to the article template. The combination of the fibers and the pre-polymerized mixture may be heated to a polymerization temperature where the monomers polymerize around the fibers and form at least a portion of the composite article. The article may then be removed from the article template. Examples of the fiber-reinforced composite articles may include wind turbine blades for electric power generation.

First claim

What is claimed is:

1. A method of making a fiber-reinforced composite article, the method comprising:
providing fibers to an article template, wherein the fibers have been treated with a coupling-initiator compound and the coupling-initiator compound has the formula:
S—X—(I) n

wherein:
n is an integer having a value between 1 and 5,
S comprises a silicon-containing coupling moiety through which the coupling-initiator compound bonds to a substrate surface on the fibers,
X comprises a linking moiety to link the S moiety with the one or more I moieties,
(I) n comprises one or more polymerization initiator moieties,
each of the initiator moieties is capable of initiating a polymerization of a monomer at the polymerization temperature, and
each of the initiator moieties is the same or different;

providing a pre-polymerized mixture comprising the monomer and a catalyst to the article template;
heating a combination of the fibers and the pre-polymerized mixture to a polymerization temperature where the monomers polymerize around the fibers and form at least a portion of the composite article, wherein the portion of the composite article comprises a thermoplastic polymer; and
removing the composite article from the article template.

2. The method of claim 1 , wherein at least one of the initiator moieties (I), comprises an organo-cyclic ring having the formula:

wherein

 represents a C 3 to C 12 substituted or unsubstituted cyclic hydrocarbon chain.

3. The method of claim 2 , wherein at least one of the initiator moieties (I) n has the formula:

4. The method of claim 1 , wherein the monomer comprises a lactam and the polymerized monomers comprise a polyamide.

5. The method of claim 4 , wherein the lactam monomer comprises caprolactam and the polyamide comprises nylon 6.

6. The method of claim 1 , wherein the catalyst comprises a salt of a lactam, wherein the salt is an alkali metal salt or an alkali-earth metal salt.

7. The method of claim 6 , wherein the catalyst comprises magnesium bromide caprolactam.

8. The method of claim 1 , wherein the pre-polymerized mixture is provided as a liquid to the article template and infused around the fibers to form the combination of the fibers and the pre-polymerized mixture.

9. The method of claim 1 , wherein at least a portion of the pre-polymerized mixture provided to the article template includes solid particles comprising the monomer and the catalyst.

10. The method of claim 1 , wherein the method further comprises:
applying a solid-phase pre-polymerized fiber-containing material to the article template, wherein the pre-polymerized fiber-containing material comprises fibers in contact with a combination of the monomer and the polymerization catalyst, and wherein the fibers have been treated with the coupling-initiator compound, and
wherein the pre-polymerized fiber-containing material is heated with the combination of the fibers and the pre-polymerized mixture to form at least a portion of the composite article.

11. The method of claim 10 , wherein the method further comprises heating the pre-polymerized fiber-containing material to a melting temperature where the monomer melts but does not polymerize; and
infusing the molten monomer around the fibers before raising the pre-polymerized fiber-containing material to the polymerization temperature.

12. The method of claim 1 , wherein the method further comprises adding more of the monomer to the to the article template after providing the pre-polymerized mixture to the article template.

13. The method of claim 12 , wherein more of the polymerization catalyst is added with the additional monomer.

14. A fiber-reinforced composite article comprising:
a thermoplastic polymer matrix; and
fibers bonded to the thermoplastic polymer matrix by a reacted coupling-initiator compound coupled to the fibers prior to contact with thermoplastic polymer matrix, wherein the coupling-initiator compound initiated the polymerization of the thermoplastic polymer, and the coupling-initiator compound has the formula:
S—X—(I) n

wherein:
n is an integer having a value between 1 and 5,
S comprises a silicon-containing coupling moiety through which the coupling-initiator compound bonds to a substrate surface on the fibers,
X comprises a linking moiety to link the S moiety with the one or more I moieties,
(I) n comprises one or more polymerization initiator moieties,
each of the initiator moieties is capable of initiating a polymerization of the monomer at the polymerization temperature, and
each of the initiator moieties is the same or different.

15. A process for preparing a reinforced resin material comprising the steps of:
providing an inorganic substrate;
applying to the inorganic substrate a sizing composition comprising a coupling activator compound of the formula:

wherein:
X and Y comprise linking moieties to link the S moiety with the I moiety, and
R 3 , R 4 , and R 5 are the same or different, and are selected from the group consisting of an alkyl group, an aryl group, an alkoxy group, a halogen group, and an alkylcyclic group;

mixing the sized inorganic substrate with a monomer and a polymerization catalyst to form a polymerization mixture; and
exposing the polymerization mixture to conditions sufficient to cause polymerization of the monomer to form a reinforced resin in which the inorganic substrate is coupled to the surrounding polymer matrix.

16. A method of making a fiber-reinforced composite article, the method comprising:
providing a pre-polymerized fiber-containing material comprising fibers in contact with a combination of a monomer and polymerization catalyst, wherein the fibers have been treated with a coupling-initiator compound;
applying the pre-polymerized fiber-containing material to an article template;
heating the pre-polymerized fiber-containing material to a polymerization temperature where the monomers polymerize around the fibers to form at least a portion of the composite article; and
wherein the coupling-initiator compound has the formula:
S—X—(I) n

wherein n is an integer having a value of 2 or more;
S comprises a silicon-containing coupling moiety through which the coupling-initiator compound bonds to a substrate surface on the fibers;
X comprises a linking moiety to link the S moiety with the 2 or more I moieties; and
(I) n comprises 2 or more polymerization initiator moieties, wherein each of the initiator moieties is capable of initiating a polymerization of the monomer at the polymerization temperature, and wherein each of the initiator moieties is the same or different.

17. The method of claim 16 , wherein the method further comprises removing the composite article from the article template.

18. The method of claim 16 , wherein the composite article further comprises at least a portion of the article template.

19. The method of claim 16 , wherein the combination of the monomer and polymerization catalyst is a solid at room temperature, and the pre-polymerized fiber-containing material is solid when applied to

Assignees

• Johns Manville

Inventors

• Tadepalli Rajappa
• Asrar Jawed
• Gleich Klaus Friedrich

Classifications

• B29C70/443

  and impregnating by vacuum or injection · CPC title

• C08J5/24

  Impregnating materials with prepolymers which can be polymerised in situ, e.g. manufacture of prepregs · CPC title

• B29K2105/12

  of short lengths, e.g. chopped filaments, staple fibres or bristles · CPC title

• B29C70/36 Primary

  and impregnating by casting, e.g. vacuum casting · CPC title

• C03C25/26

  Macromolecular compounds or prepolymers · CPC title