EP3802930A1

EP3802930A1 - Reformable resin filaments and materials formed therewith

Info

Publication number: EP3802930A1
Application number: EP19739750.8A
Authority: EP
Inventors: Jason Walker
Original assignee: Zephyros Inc
Current assignee: Zephyros Inc
Priority date: 2018-06-11
Filing date: 2019-06-11
Publication date: 2021-04-14
Also published as: BR112020025140A2; IL279233A; US20210310157A1; MX2020013572A; WO2019241295A1; AU2019284620A1

Abstract

The present teachings contemplate forming a reformable epoxy resin material into a monofilament having a denier of from about 50 to about 5000 and a glass transition temperature of less than about 200 °C; loading one or more monofilaments onto a spool; co-weaving the one or more monofilaments with a reinforcing fiber to form a woven material, the reinforcing fiber having a glass transition temperature of greater than 200 °C; heating the woven material to form a composite to a temperature so that only the one or more monofilaments soften but the reinforcing fiber does not.

Description

REFORMABLE RESIN FILAMENTS AND MATERIALS FORMED THEREWITH

Technical Field

[0001] The present invention pertains generally to reformable epoxy resins for use in monofilament fibers, and more particularly to drapable materials formed using said fibers and composite structures formed therewith.

Background

[0002] Industrial fiber materials often require means to hold or bind materials together. Often, thermoplastic materials (e.g., fibers) are used to stitch or bind the materials together. However, such current methods include a number of drawbacks including but not limited to the incompatibility of typical thermoplastics with secondary materials (in particular epoxy-based composite materials), lack of sufficient blending, yarn showing through composite surfaces, behavior of thermoplastics upon sanding or cutting of secondary materials, rigidity of typical thermoplastics and lack of reformability of typical thermoplastics.

[0003] Reformable thermoplastic polymers having at least one epoxide group have been described in U.S. Patent Nos. 5, 1 15,075; 4,438,254; 6,011 , 11 1 ; and WO 98/14498 (see e.g., pages 3-8) along with illustrative synthesis conditions, all incorporated by reference herein (see also U.S. Patent No. 3,317,471 and 4,647,648, also incorporated by reference herein). Examples of such materials (e.g., reformable resin materials) also can be found, without limitation at paragraphs 15-25 of Published U.S. Patent Application No. 20070270515 (Chmielewski et al), incorporated by reference for all purposes.

[0004] The use of such thermoplastic polymers in a composite material has been disclosed in PCT Publication number WO/2008/010823 (addressing in situ reaction of an epoxy and an amine after impregnation), incorporated by reference herein.

[0005] Yarns utilizing these reformable epoxy resin materials have been disclosed in PCT publication number WO2016/065104. However, this disclosure fails to identify monofilaments having the required denier for use on the composite structures described herein.

[0006] There is thus a need for materials that have certain thermoplastic capabilities and desirable small denier in a single monofilament in that they can be woven with fibers having much higher glass transition to promote constant thickness of a composite structure formed by the woven material.

l Summary of the Invention

[0007] The teachings herein are directed to a method comprising forming a reformable epoxy resin material into a monofilament having a denier of from about 50 to about 1000 and a glass transition temperature of less than about 200°C, loading one or more monofilaments onto a spool, co-weaving the monofilaments with a reinforcing fiber to form a woven material, the reinforcing fiber having a glass transition temperature of greater than 200°C, heating the woven material to form a composite to a temperature so that only the one or more monofilaments soften but the reinforcing fiber does not.

[0008] The reinforcing fiber may be selected from the group consisting of glass fibers, carbon fibers, aramid fibers, polymer fibers (e.g., polyethylene, polypropylene, polyamide, polyester) and combinations thereof. The resulting composite may have a constant thickness as a result of the failure of the structural fibers to soften. The resulting composite may be utilized to form an armor material (e.g., a composite armor material or a composite ballistic armor material). The resulting composite may be used to form a helmet, a jacket, a shield or the like. One or more of the denier or diameter of the monofilament may be substantially similar to that of the reinforcing fiber. One or more of the denier or diameter of the monofilament may be less than that of the reinforcing fiber. One or more of the denier or diameter of the monofilament may be greater than that of the reinforcing fiber. The resulting composite may be an epoxy laminate. The resulting composite may be substantially free of any film layer.

[0009] The method may be substantially free of surface treatment for forming class A surfaces. The resulting composite may be paintable. The monofilament may develop adhesive properties upon softening. The shelf life of the monofilament may be at least about 3 months, at least about 6 months, at least about 1 year, or even at least about 5 years. The monofilament may be recyclable. The resulting composite may be drapable.

[0010] The teachings herein are also directed to a monofilament having a denier of from about 5 to 5000, or from about 200 to 3200 and a glass transition temperature of less than about 200 °C and comprising a reformable epoxy resin material. The reformable epoxy resin material may be formed as a reaction product of a difunctional epoxy resin and a primary amine. The reformable epoxy resin material may be formed as a reaction product of bisphenol A diglycidyl ether (BADGE) and monoethanolamine. The monofilament may be drapable. The monofilament may be woven to form an end product that is drapable. [0011] The teachings herein are further directed to a fibrous material product formed from the monofilament described herein woven with one or more reinforcing fibers having a glass transition temperature of 200 °C or greater. The fibrous material product may be drapable.

[0012] Also, envisioned are ballistic composite materials including one or more layers comprising a woven material formed from a plurality of reformable epoxy resin monofilaments and a plurality of reinforcing fibers. The composite material may be used to form a helmet. The composite material may be used to form body armor. The composite material may be used to form a shield. The composite material may be formed in a heated press at a temperature below about 200 °C.

[0013] The teachings herein provide for a reformable resin monofilament having a particular denier and glass transition temperature so that it can be woven with a reinforcing fiber to form a composite having a substantially constant thickness after exposure to heat for forming the composite.

Detailed Description

[0014] The present teachings meet one or more of the above needs by the improved composite structures and methods described herein. The explanations and illustrations presented herein are intended to acquaint others skilled in the art with the teachings, its principles, and its practical application. Those skilled in the art may adapt and apply the teachings in its numerous forms, as may be best suited to the requirements of a particular use. Accordingly, the specific embodiments of the present teachings as set forth are not intended as being exhaustive or limiting of the teachings. The scope of the teachings should, therefore, be determined not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. The disclosures of all articles and references, including patent applications and publications, are incorporated by reference for all purposes. Other combinations are also possible as will be gleaned from the following claims, which are also hereby incorporated by reference into this written description.

[0015] This application is related to and claims the benefit of the filing date of U.S. Provisional Application Serial No. 62/683,229, filed June 1 1 , 2018, the contents of that application being hereby incorporated by reference herein for all purposes.

[0016] The teachings herein make advantageous use of a reformable epoxy filament (e.g., monofilament) that adheres when cooled. The teachings herein contemplate a method for providing composite structures or other molded structures that are assembled (e.g., stitched, woven or formed with a web or mesh) with the filaments (e.g., weavable reformable epoxy resin filaments) described herein. The resulting structures are formable and moldable after the reformable epoxy monofilament is heated and subsequently falls below its glass transition temperature. The reformable epoxy filaments are particularly compatible with dissimilar reinforcing fibers and epoxy based secondary materials such that the compatibility is improved over typical thermoplastic fibers (e.g., polyester). The glass transition temperature of the reinforcing fibers may be higher than that of the reformable epoxy filaments may be heated may be heated and softened while the reinforcing fibers do not soften.

[0017] The teachings herein provide for a number of uses for the reformable epoxy monofilaments. In one embodiment, the reformable epoxy filaments may be woven with reinforcing fibers. Examples of which include but are not limited to glass, carbon, aramid, and/or polyamide fibers. The reformable epoxy filaments may be more compatible with the reinforcing fibers as compared to typical thermoplastic fibers. This may be due to the similarity in size, diameter and/or denier of the reformable epoxy filaments and reinforcing fibers. For example, the reformable epoxy monofilaments may have a denier of from about 5 to about 6000, from about 30 to about 4000, from about 175 to about 3800, or even from about 200 to about 3200. The reformable epoxy monofilaments may have a denier of from about 100 to about 1000, from about 150 to about 500, or even from about 200 to about 400. Upon weaving the reformable epoxy monofilaments with a reinforcing fiber, these woven structures fibers can be used to produce drapable materials and composites that maintain desired consistent thickness, strength and adhesion. The flexible nature of the resulting structures are easier to form than rigid composites, enable more complex shapes, require less heat/energy to process, and has a higher modulus than typical thermoplastic fibers.

[0018] In another embodiment, the reformable epoxy filament may be combined with additional monofilaments to a desired thickness and those combined filaments may be woven with a reinforcing fiber. This allows for specific customization of the size of the reformable epoxy material so that the epoxy filaments are compatible with a selected reinforcing fiber.

[0019] The materials and methods taught herein include possible uses for reformable epoxy filaments. It is possible that the reformable epoxy materials may be provided initially in a pellet form and then formed into a spooled filament. The spooled filament and a spooled reinforcing fiber may be located adjacent one another for simplified weaving.

[0020] The reformable epoxy monofilaments described herein may be utilized to form composite structures that can be molded to form helmets, body armor, shields, or protective armor (e.g., a composite armor material or a composite ballistic armor material) of any kind. It is desirable that these composites (or the layer of the composite formed with the reformable epoxy monofilaments) have a consistent cross section and/or thickness. This is made possible by weaving the filaments with a reinforcing fiber, whereby when exposed to elevated temperatures, the reformable epoxy filaments soften and adhere and the reinforcing fibers do not soften and are thus capable of maintaining the desired consistent cross section and/or thickness.

[0021] The processing temperature may affect the yarn formation process in that the viscosity of the reformable epoxy materials my require adjustment to form the desired monofilaments. Specifically, the materials may require processing at a temperature of at least 150 °C, at least 170 °C, at least 190 °C or even at least about 200 °C. At lower processing temperatures the viscosity of the materials may be too high for formation into monofilaments. In one embodiment it is possible that the material is formulated to have a lower viscosity (sufficient for forming into filaments) even at temperatures below 200 °C, below 170 °C, or even below 150 °C. However, the temperature for processing the reformable epoxy materials may continue to be below that of the temperature required to process fibers formed of other materials such as typical thermoplastics. The use of lower processing temperatures reduces the risk of thermal stability of the filaments during processing and also allows for easier cooling of the filaments. Cooled filaments minimize any unwanted fiber tackiness so that the filaments are not sticky when wound.

[0022] A key advantage of the present teachings over existing commonly used fibers (e.g., polyester fibers) is the improved compatibility with other materials including epoxy-based thermoset epoxy resin matrix materials (commonly utilized in composite structures). Specifically, the reformable monofilament may be an amine terminated resin that can potentially react with a thermoset resin. Further, the low glass transition temperature of the filaments described herein are beneficial in that the disclosed filaments can be easily softened at a low temperature without softening the reinforcing fibers woven with the reformable epoxy filaments. Additional benefits of the reformable epoxy filaments include fast adhesion, and also the ability to re-form and re-mold the filaments with the addition of heat. Adhesion and returning to a solid state upon cooling of the reformable epoxy filaments begins almost immediately after heating is stopped and full adhesion can occur within about 10 seconds to about 60 seconds (e.g., about 30 seconds). In addition, a reformable epoxy filaments may be desirable because of its long shelf life. It also may not require storage at a refrigerated temperature, unlike some alternative materials.

[0023] As an example, the reformable epoxy material for forming the filaments may be and/or may include a product (e.g., a thermoplastic condensation reaction product) of a reaction of a mono-functional or di-functional species (i.e. , respectively, a species having one or two reactive groups, such as an amide containing species), with an epoxide-containing moiety, such as a diepoxide (i.e., a compound having two epoxide functionalities), reacted under conditions for causing the hydroxyl moieties to react with the epoxy moieties to form a generally linear backbone polymer chain with ether linkages. Exemplary reformable epoxy materials may be made with a difunctional epoxy resin and a primary amine which may be bisphenol A diglycidyl ether (BADGE) and monoethanolamine. For some applications that may require a higher glass transition temperature (T_g), it is contemplated that BADGE may be replaced by an epoxy monomer with less mobility. Such epoxy monomers may include diglycidylether of fluoren diphenol or 1 ,6 napthalene diepoxy. Also, it is contemplated that where fire resistance is desired, BADGE can be replaced by a brominated bisphenol A epoxy resin. Alternatively, the reformable epoxy materials disclosed herein may also be known as poly(hydroxyamino ether) (PHAE) as illustrated in U.S. Pat. Nos. 5, 164,472; 5,275,853; 5,401 ,814 and 5,464,924, all incorporated by reference herein for all purposes. Such polyethers may be prepared by reacting a diglycidyl ether of dihydric aromatic compounds such as the diglycidyl ether of bisphenol A, or a diepoxy-functionalized poly(alkylene oxide) or mixture thereof with a primary amine or a secondary diamine or a monoamine functionalized poly(alkylene oxide) or mixture thereof. Such material generally has a relatively high flexural strength and modulus— often much higher than typical polyolefins (i.e. polyethylene and polypropylene)— and has the added benefit of being melt processable at temperatures of 150 to 200° C. Though other epoxide-containing moieties may be employed, as is taught in U.S. Patent No. 6,01 1 , 11 1 (incorporated by reference; see, e.g., Cols. 5-6), and WO 98/14498 (incorporated by reference; see, e.g., page 8) such moieties may include at least one mono-functional epoxide and/or a di-functional epoxide (“diepoxide”). An example of a diepoxide that can be employed in the teachings includes a diglycidyl ether of a dihydric phenol (e.g., resorcinol, biphenol or bisphenol A). Any epoxide-containing moiety herein may be an aliphatic and/or an aromatic epoxide.

[0024] Other examples of illustrative materials, functional species and diepoxides are described in U.S. Patent Nos. 5, 1 15,075; 4,438,254; and WO 98/14498 (see e.g., pages 3-8) along with illustrative synthesis conditions, all incorporated by reference herein (see also U.S. Patent No. 3,317,471 and 4,647,648, also incorporated by reference herein). Examples of such materials also can be found, without limitation at paragraphs 15-25 of Published U.S. Patent Application No. 20070270515 (Chmielewski et al), incorporated by reference for all purposes.

[0025] Forming the reformable epoxy materials into the desired monofilament format may require particularly high temperatures during the extrusion process. Accordingly, it may be necessary to reduce the viscosity of the RER as the heat tends to increase the viscosity to an undesirable range. This may be achieved by modifying the ratio of the difunctional epoxy resin and primary amine such that the molecular chain length is reduced thus reducing the viscosity. [0026] As used herein, unless otherwise stated, the teachings envision that any member of a genus (list) may be excluded from the genus; and/or any member of a Markush grouping may be excluded from the grouping.

[0027] Unless otherwise stated, any numerical values recited herein include all values from the lower value to the upper value in increments of one unit provided that there is a separation of at least 2 units between any lower value and any higher value. As an example, if it is stated that the amount of a component, a property, or a value of a process variable such as, for example, temperature, pressure, time and the like is, for example, from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, it is intended that intermediate range values such as (for example, 15 to 85, 22 to 68, 43 to 51 , 30 to 32 etc.) are within the teachings of this specification. Likewise, individual intermediate values are also within the present teachings. For values which are less than one, one unit is considered to be 0.0001 , 0.001 , 0.01 or 0.1 as appropriate. These are only examples of what is specifically intended and all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be expressly stated in this application in a similar manner. As can be seen, the teaching of amounts expressed as "parts by weight" herein also contemplates the same ranges expressed in terms of percent by weight. Thus, an expression in the of a range in terms of at "'c' parts by weight of the resulting polymeric blend composition" also contemplates a teaching of ranges of same recited amount of "x" in percent by weight of the resulting polymeric blend composition."

[0028] Unless otherwise stated, all ranges include both endpoints and all numbers between the endpoints. The use of "about" or "approximately" in connection with a range applies to both ends of the range. Thus, "about 20 to 30" is intended to cover "about 20 to about 30", inclusive of at least the specified endpoints.

[0029] The disclosures of all articles and references, including patent applications and publications, are incorporated by reference for ail purposes. The term "consisting essentially of to describe a combination shall include the elements, ingredients, components or steps identified, and such other elements ingredients, components or steps that do not materially affect the basic and novel characteristics of the combination. The use of the terms "comprising" or "including" to describe combinations of elements, ingredients, components or steps herein also contemplates embodiments that consist of, or consist essentially of the elements, ingredients, components or steps.

[0030] Plural elements, ingredients, components or steps can be provided by a single integrated element, ingredient, component or step. Alternatively, a single integrated element, ingredient, component or step might be divided into separate plural elements, ingredients, components or steps. The disclosure of "a" or "one" to describe an element, ingredient, component or step is not intended to foreclose additional elements, ingredients, components or steps.

[0031] It is understood that the above description is intended to be illustrative and not restrictive. Many embodiments as well as many applications besides the examples provided will be apparent to those of skill in the art upon reading the above description. The scope of the invention should, therefore, be determined not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. The disclosures of all articles and references, including patent applications and publications, are incorporated by reference for all purposes. The omission in the following claims of any aspect of subject matter that is disclosed herein is not a disclaimer of such subject matter, nor should it be regarded that the inventors did not consider such subject matter to be part of the disclosed inventive subject matter.

Claims

What is claimed is:

1) A method comprising:

i) forming a reformable epoxy resin material into a monofilament having a

denier of from about 50 to about 4000 and a glass transition temperature of less than about 200 °C;

ii) loading one or more monofilament onto a spool;

iii) co-weaving the one or more monofilaments with a reinforcing fiber to form a woven material, the reinforcing fiber having a glass transition temperature of greater than 200 °C;

iv) heating the woven material to form a composite to a temperature so that only the one or more monofilaments softens but the reinforcing fiber does not.

2) The method according to claim 1 , wherein the reinforcing fiber is selected from the group consisting of glass fibers, carbon fibers, aramid fibers, polymer fibers (e.g., polyethylene, polypropylene, polyamide, polyester), metallic fibers, and combinations thereof.

3) The method according to claim 1 or claim 2, wherein the resulting composite has a

constant thickness as a result of the failure of the structural fibers to soften.

4) The method according to any one of claims 1 through 3, wherein the resulting composite is utilized to form an armor material (e.g., a composite armor material or a composite ballistic armor material).

5) The method according to any one of claims 1 through 4, wherein the resulting composite is used to form a helmet, a jacket, a shield or the like.

6) The method according to any one of claims 1 through 5, wherein one or more of the denier or diameter of the monofilament is substantially similar to that of the reinforcing fiber.

7) The method according to any one of claims 1 through 6, wherein one or more of the denier or diameter of the monofilament is less than that of the reinforcing fiber.

8) The method according to any one of claims 1 through 6, wherein one or more of the denier or diameter of the monofilament is greater than that of the reinforcing fiber.

9) The method according to any one of claims 1 through 8, wherein the resulting composite is an epoxy laminate.

10) The method according to any one of claims 1 through 9, wherein the resulting composite is substantially free of any film layer. 11) The method according to any one of claims 1 through 10, wherein the method is substantially free of surface treatment for forming class A surfaces.

12) The method according to any one of claims 8 through 11 , wherein the resulting

composite is paintable.

13) The method of any one of claims 1 through 12, wherein the monofilament develops

adhesive properties upon softening.

14) The method according to any one of claims 1 through 13, wherein the shelf life of the monofilament is at least about 3 months, at least about 6 months, at least about 1 year, or even at least about 5 years.

15) The method according to any one of claims 1 through 14, wherein the monofilament is recyclable.

16) The method according to any one of claims 1 through 15, wherein the resulting

composite is drapable.

17) A monofilament having a denier of from about 200-3200 and a glass transition

temperature of less than about 200°C and comprising a reformable epoxy resin material.

18) The monofilament of claim 17, wherein the reformable epoxy resin material is formed as a reaction product of a difunctional epoxy resin and a primary amine.

19) The monofilament of claims 17 or 18, wherein the reformable epoxy resin material is formed as a reaction product of bisphenol A diglycidyl ether (BADGE) and

monoethanolamine.

20) The monofilament of any of claims 17 through 19, wherein the monofilament is drapable.

21) The monofilament of any of claims 17 through 19, wherein the monofilament is woven to form an end product that is drapable.

22) A fibrous material product formed from the monofilament of any of claims 17 through 21 woven with one or more reinforcing fibers having a glass transition temperature of 200 °C or greater.

23) The fibrous material product of claim 22, wherein the product is drapable.

24) A ballistic composite material including one or more layers comprising a woven material formed from a plurality of reformable epoxy resin monofilaments and a plurality of reinforcing fibers.

25) The composite material of claim 24, wherein the material is used to form a helmet.

26) The composite material of claim 24, wherein the material is used to form body armor.

27) The composite material of claim 24, wherein the material is used to form a shield. 28) The composite material of claim 24, wherein the composite is formed in a heated press at a temperature below about 200 °C.