阅读说明：本技术 含有伯胺或仲胺的杂环胺作为聚合物催化剂或硬化剂的用途 (Use of heterocyclic amines containing primary or secondary amines as polymer catalysts or hardeners ) 是由 S·科辛斯基 S·洛 T·莫尔丁 S·N·拉贾 N·G·里卡皮托 A·萨菲尔 于 2019-06-14 设计创作，主要内容包括：一种环氧树脂组合物,其包含占组合物约70重量％至约95重量％的环氧组分,和占组合物约5重量％至约30重量％的固化组分,其中所述固化组分包括咪唑；其中环氧组分和固化组分在约100℃至约130℃的温度下一起反应,以在约10分钟或更短时间内形成基本上固化的反应产物,并且所述固化的产物显示出高拉伸强度和挠曲强度。(An epoxy resin composition comprising an epoxy component comprising from about 70% to about 95% by weight of the composition, and a curing component comprising from about 5% to about 30% by weight of the composition, wherein the curing component comprises imidazole; wherein the epoxy component and the curing component react together at a temperature of about 100 ℃ to about 130 ℃ to form a substantially cured reaction product in about 10 minutes or less, and the cured product exhibits high tensile strength and flexural strength.)

1. An article comprising a cured polymer, wherein the cured polymer has:

(i) a tensile strength of not less than 10000 psi (68948 kPa) as determined by ISO527-1(2012) or a flexural strength of not less than 17000 psi (117211 kPa) as determined by ISO 178 (2010); and

(ii) an elongation at break of at least 2% as determined by ISO527-1(2012) or a flexural strain of at least 4% as determined by ISO 178 (2010).

2. The article of claim 1, wherein the tensile strength is not less than 10500 psi (72395 kPa), not less than 11000 psi (75843 kPa), not less than 11300 psi (77911 kPa), not less than 11500 psi (79290 kPa), not less than 11800 psi (81359 kPa), not less than 12000 psi (82738 kPa), not less than 12200 psi (84117 kPa), not less than 12400 psi (85495 kPa), not less than 12600 psi (86874 kPa), or not less than 12800 psi (88253 kPa);

or wherein the flexural strength is not less than 17500 psi (120659 kPa), not less than 18000 psi (124106 kPa), not less than 18500 psi (127554 kPa), not less than 19000 psi (131001 kPa), not less than 19500 psi (134448 kPa), not less than 20000 psi (137896 kPa), not less than 20200 psi (139275 kPa), not less than 20400 psi (140653 kPa), not less than 20600 psi (142032 kPa), not less than 20800 psi (143411 kPa), not less than 21000 psi (144790 kPa), not less than 21200 psi (146169 kPa), not less than 21400 psi (147549 kPa), not less than 21600 psi (148927 kPa), or not less than 21800 psi (150306 kPa).

3. The article of any one of the preceding claims, wherein the elongation at break is at least 2.1%, at least 2.2%, at least 2.3%, at least 2.4%, at least 2.5%, at least 2.6%, at least 2.7%, at least 2.8%, at least 2.9%, at least 3%, at least 3.2%, at least 3.4%, at least 3.6%, at least 3.8%, at least 4%, at least 4.3%, at least 4.5%, at least 4.8%, at least 5%, at least 5.3%, at least 5.5%, at least 5.8%, or at least 6%;

or wherein the flexural strain is at least 4.1%, at least 4.2%, at least 4.3%, at least 4.4%, at least 4.5%, at least 4.6%, at least 4.7%, at least 4.8%, at least 4.9%, at least 5%, at least 5.2%, at least 5.4%, at least 5.6%, at least 5.8%, at least 6%, at least 6.3%, at least 6.5%, at least 6.8%, at least 7%, at least 7.3%, at least 7.5%, at least 7.8%, or at least 8%.

4. The article of any one of the preceding claims, wherein the cured polymer has a glass transition temperature T as determined by differential scanning calorimetry according to ASTM D7028_gIs at least 120 ℃, at least 125 ℃, at least 130 ℃, at least 132 ℃, at least 134 ℃, at least 136 ℃, at least 138 ℃, at least 140 ℃, at least 142 ℃, at least 144 ℃, at least 146 ℃, at least 148 ℃, at least 150 ℃, at least 152 ℃ or at least 154 ℃.

5. The article of any one of the preceding claims, wherein the cured polymer comprises an epoxy polymer, a polyester, a polyamide, a polyimide, a polyurethane, a polyacrylate, a polyacrylamide, a polyketone, or any combination thereof.

6. The article of any one of the preceding claims, wherein the cured polymer consists essentially of an epoxy polymer.

7. The article of any one of the preceding claims, wherein the cured polymer is a reaction product of a reaction comprising a curing component, wherein the curing component comprises

(i) A primary or secondary amine, or a mixture thereof,

(ii) a tertiary amine, an aromatic amine or imine, and

(iii) free base form having a molecular weight greater than 70 g/mol.

8. The article of claim 7, wherein the aromatic amine comprises a moiety selected from imidazole, pyridine, pyrimidine, pyrazine, benzimidazole, thiazole, oxazole, pyrazole, isoxazole, isothiazole, or any mixture thereof.

9. The article of claim 7, wherein the curing component further comprises a primary amine and a secondary amine.

10. The article of claim 7, wherein the curing component is selected from the group consisting of:

wherein R is₁And R₂Not both hydrogen, and is selected from aminoalkyl, hydroxyalkyl, amino-hydroxyalkyl, or any combination thereof.

11. The article of claim 10, wherein the curing component is selected from the group consisting of:

wherein R is₃Selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl or isobutyl.

12. The article of claim 7, wherein the curing component is selected from the group consisting of:

or any of the enantiomers or diastereomers described above.

13. A resin composition comprising:

at least one polymer component comprising from about 70% to about 98% by weight of the resin composition; and

a curing component comprising from 2% to about 30% by weight of the composition, wherein the curing component comprises

(i) A secondary or primary amine, or a mixture thereof,

(ii) a tertiary amine, an aromatic amine or imine, and

(iii) free base form having a molecular weight greater than 70 g/mol.

14. The resin composition of claim 13, wherein the curing component comprises a secondary amine and a primary amine.

15. The resin composition of claim 14, wherein the primary amine of the curing component is within a radius of less than 100nm, less than 90nm, less than 80nm, less than 70nm, less than 60nm, or less than 50nm from the secondary amine nitrogen.

16. The resin composition of claim 14, wherein the aromatic amine or imine is within a radius from the secondary amine nitrogen of less than 50nm, less than 40nm, less than 30nm, less than 20 nm.

17. The resin composition of claim 13, wherein the polymer component is selected from the group consisting of: an epoxy component, a carboxylic acid ester component, a carboxylic acid anhydride component, an isocyanate component, an acrylonitrile component, a urea component, an aldehyde component, a ketone component, or any combination thereof.

18. The resin composition of claim 13, wherein the polymer component and the curing component react together at a temperature of about 90 ℃ to about 140 ℃ in less than 10 minutes to substantially form a cured polymer.

19. A method, comprising:

mixing a curing component and a polymer component to form a resin;

transferring the resin to a mold;

at a curing temperature T of less than 140 DEG C_cCuring the resin for a curing time t of not more than 10 minutes_c(ii) a And

removing the substantially cured article from the mold, wherein the article has:

(i) a tensile strength of not less than 10000 psi (68948 kPa) as determined by ISO527-1(2012) or a flexural strength of not less than 17000 psi (117211 kPa) as determined by ISO 178 (2010); and

(ii) an elongation at break of at least 2% as determined by ISO527-1(2012) or a flexural strain of at least 4% as determined by ISO 178 (2010).

20. The method of claim 19, wherein T_cIs less than138 deg.C, less than 135 deg.C, less than 130 deg.C, less than 125 deg.C, less than 120 deg.C, less than 115 deg.C, or less than 110 deg.C; or

t_cNo more than 9 minutes, no more than 8 minutes, no more than 7 minutes, no more than 6 minutes, no more than 5 minutes, no more than 4 minutes, no more than 3.5 minutes, no more than 3 minutes, no more than 2.5 minutes, no more than 2 minutes, no more than 1.5 minutes, or no more than 1 minute.

21. The method of claim 19, wherein the polymer component has a number of reactive functionalities n_rAnd the curing component has a curing functionality n_cAnd wherein the resin has an n of no greater than 0.98, no greater than 0.95, no greater than 0.9, no greater than 0.85, no greater than 0.8, no greater than 0.75, no greater than 0.7, no greater than 0.65, no greater than 0.6, no greater than 0.55, no greater than 0.5, no greater than 0.45, no greater than 0.4, no greater than 0.38, no greater than 0.36, no greater than 0.34, no greater than 0.32, no greater than 0.30, no greater than 0.28, no greater than 0.26, no greater than 0.24, no greater than 0.22, no greater than 0.2, no greater than 0.18, or no greater than 0._c:n_rThe ratio of (a) to (b).

22. An epoxy resin composition comprising:

an epoxy component comprising from about 70% to about 95% by weight of the composition; and

from about 5% to about 30% by weight of the composition of a curing component, wherein the curing component comprises an imidazole selected from the group consisting of:

wherein R is₁And R₂Not both hydrogen and is selected from the group consisting of aminoalkyl, hydroxyalkyl, amino-hydroxyalkyl, and any combination thereof; wherein the epoxy component and the curing component react together at a temperature of about 100 ℃ to about 130 ℃ to form a substantially cured reaction product in about 10 minutes or less; wherein the cured reaction product has：

(i) A tensile strength of not less than 10000 psi (68948 kPa) as determined by ISO527-1(2012) or a flexural strength of not less than 17000 psi (117211 kPa) as determined by ISO 178 (2010); and

(ii) an elongation at break of at least 2% as determined by ISO527-1(2012) or a flexural strain of at least 4% as determined by ISO 178 (2010).

23. The epoxy resin composition of claim 22, wherein the curing component is selected from the group consisting of: 2- (3-aminopropyl) -imidazole, 2- (2-aminoethyl) -imidazole, 2- (aminomethyl) -imidazole, 4- (3-aminopropyl) -imidazole, 4- (2-aminoethyl) -imidazole, 4- (aminomethyl) -imidazole and mixtures thereof.

24. The epoxy resin composition of any one of the preceding claims, starting from claim 22, wherein the resin composition has a cured glass transition temperature, T, of about 130 ℃ or more_g。

25. The epoxy resin composition of any preceding claim beginning with claim 22, wherein the curing component further comprises at least one hardener, wherein the hardener is present in an amount from about 1 weight percent to about 25 weight percent of the composition, the imidazole is present in an amount from about 5 weight percent to about 10 weight percent of the composition, and the epoxy component is present in an amount from about 70 weight percent to about 94 weight percent of the composition.

26. The epoxy resin composition of claim 25, wherein the hardener is selected from the group consisting of: isophorone diamine ('IPDA'), 1,3- (bis (aminomethyl) cyclohexane ('BAC'), bis-9 p-aminocyclohexyl) methane ('PALM'), diethylene triamine ('DETA'), triethylene tetramine ('TETA'), tetraethylene pentamine ('TEPA'), 4,7, 10-trioxa-1, 13-tridecane, or any mixture thereof.

27. An epoxy resin composition according to any preceding claim starting from claim 22, wherein the epoxy resin comprises any one selected from the group consisting of: 2, 2-bis- (4-glycidyloxyphenyl) -propane (DGEBA); bis- (4-glycidyloxyphenyl) -methane ('DGEBF'); bis (3, 4-glycidyloxycyclohexylmethyl) oxalate; bis (3, 4-glycidyloxycyclohexylmethyl) adipate; bis (3, 4-glycidyloxy-6-methylcyclohexylmethyl) adipate; diglycidyl oxyethylcyclohexene; diglycidyl oxymlimonene; triglycidyl-p-aminophenol; n, N-tetraglycidyl-4, 5-methylenebisbenzylamine; and any mixtures thereof.

28. A composite product comprising the reaction product of an epoxy resin composition comprising:

an epoxy component comprising from about 70% to about 95% by weight of the composition; and

from about 5% to about 30% by weight of the composition of a curing component, wherein the curing component comprises an imidazole selected from the group consisting of:

wherein R is₁And R₂Not both are hydrogen and are selected from aminoalkyl, hydroxyalkyl, amino-hydroxyalkyl or any combination thereof;

wherein the epoxy component and the curing component react together at a temperature of about 100 ℃ to about 130 ℃ to form a substantially cured reaction product in about 10 minutes or less; wherein the cured reaction product has:

(i) a tensile strength of not less than 10000 psi (68948 kPa) as determined by ISO527-1(2012) or a flexural strength of not less than 17000 psi (117211 kPa) as determined by ISO 178 (2010); and

(ii) an elongation at break of at least 2% as determined by ISO527-1(2012) or a flexural strain of at least 4% as determined by ISO 178 (2010).

29. The composite product of claim 28, further comprising reinforcing fibers.

30. The composite product of claim 29, wherein the reinforcing fibers are selected from the group consisting of: glass fibers, fiberglass, silicon carbide fibers, disilicon carbide fibers, carbon fibers, graphite fibers, boron fibers, quartz fibers, alumina fibers, carbon nanotubes, nanocomposite fibers, polyaramide fibers, poly (p-phenylene benzobisoxazole) fibers, ultra high molecular weight polyethylene fibers, high and low density polyethylene fibers, polypropylene fibers, nylon fibers, cellulosic fibers, natural fibers, biodegradable fibers, or combinations thereof.

Technical Field

The present disclosure relates generally to the field of polymer resin compositions for making composite parts, and more particularly, to fast curing epoxy resin compositions that produce cured products with high tensile and flexural strength suitable for applications requiring such properties.

Background

It is well known that thermosetting resin compositions or systems can be used to bond or impregnate various materials, such as glass fibers, carbon fiber mats or fabrics, and other reinforcing materials. Fabrication techniques for such composite structures are also known and may vary. The actual conditions for molding vary from industry to industry, ranging from consumer products to electronics to energy and transportation. Furthermore, there are different resin systems for high-pressure or low-pressure molding, for example under partial vacuum, for increasing the penetration of the resin into the reinforcement.

Thermoset materials include polyesters, epoxies, phenolics, vinyl esters, polyurethanes, silicones, polyamides, polyimides, and combinations thereof. Resins range from liquids to powders, but are rarely used as pure resins. In addition to reinforcing materials that contribute to mechanical properties, resins also require curing agents, hardeners, and other additives such as inhibitors and plasticizers. Other ingredients may be required to impart specific properties to the composite material, such as flame retardancy, uv stability, electrical conductivity, moisture or gas permeation barrier, and the like.

The amount of additives incorporated into the thermosetting resin is generally substantial and may amount to more than one third of the weight of the resin, interacting with the mechanical properties of the final product after curing. For example, conventional epoxy systems require 20 to 60phr of hardener. The curing agent concentration is expressed in parts per hundred (parts per hundred) or phr and reflects the amount, e.g., in grams, to be mixed with 100 grams of resin. Sold by Huntsman Corp. (The woods, TX)D230 is typically used at 32phr for epoxy resins, diethylenetriamine ('DETA') hardener at 21phr, and Aminoethylpiperazine (AEP) at 23 phr. Accordingly, there is a need in the industry to obtain alternatives to reduce the amount of additives or to combine functions such as curing and hardening to avoid loss of properties of the thermoset material while not interfering with conventional processing techniques.

Resin transfer molding ('RTM') is an increasingly popular form of molding in which a catalyzed, low viscosity resin composition is pumped under pressure into a mold, displacing air at the edges until the mold is filled. The mold may be filled with a fibrous preform or dry fibrous reinforcement prior to injecting the resin. After the mold is filled with resin, a resin curing cycle begins in which the mold is heated to a temperature of about 100 ℃ or higher and the resin polymerizes into a rigid state.

In the automotive industry, high pressure resin transfer molding ('HP-RTM') is a manufacturing solution used by OEMs and their suppliers to manufacture automotive structures. Such equipment typically utilizes an intelligent or computerized filling process with closed-loop control, and a high-pressure metering system with sensors for monitoring internal mold pressure. Resin injection can be managed and controlled using closed loop control. After the mold is closed, a high compression force is applied and the resin is injected at a high pressure of about 30 to about 100 bar (atm), completing the impregnation and curing of the resin.

To meet manufacturing requirements, the resin system used needs to have a cure time of about 10 minutes or less, preferably about 5 minutes or less, at typical molding temperatures of about 120 ℃ to about 140 ℃ and produce a resin with a glass transition temperature (' T) of greater than 130 ℃ without the use of post-cure or multifunctional resins_g') a substantially fully cured composite part. The resin systems (prepared by a crosslinking reaction using an appropriate curing agent and epoxy resin) used to make such composite parts, particularly thermoset polymer composite parts, desirably have the following properties: (a) low viscosities suitable for HP-RTM (e.g., about 120 centipoise or less at an injection temperature of about 120 ℃); (b) a fast cure reaction rate (e.g., about 5 minutes or less at 120 ℃, or about 3 minutes or less at 130 ℃); (c) substantially fully cured (e.g., about 95-100% cured) at the end of the reaction phase, thus no post-cure after molding is required; and (d) has a high resin T_g(e.g., greater than about 120 ℃) and high composite T_g(e.g., greater than about 130 deg.C). However, one skilled in the art recognizes that it is difficult to formulate epoxy resin compositions having all of the properties required to produce fast curing composite structures. For example, when epoxy resins cure rapidly, it is often difficult to achieve the most desirable epoxy resins that are typically available under slow curing conditionsFinal T_g. Generally, T of a fast curing sample_gT of samples slower than those of slow curing_gLower by 20 degrees.

Different resin systems or formulations have been known and available for many years. These systems typically include one or more epoxy resins, such as epoxy novolac resins and/or phenols, such as those based on bisphenol a ('BPA') and bisphenol F ('BPF'), among others. However, the epoxy resin used may affect different properties of the resin system, such as the mechanical properties and viscosity of the system.

Typically, the resin formulation also contains a hardener or curing agent, such as polyethyleneimine; a cycloaliphatic anhydride; dicyandiamide ('DICY'); imidazoles, such as N- (3-aminopropyl) imidazole ('API'); and amines, such as diethylenetriamine ('DETA') and 1, 3-bis (aminomethyl) cyclohexane ('1, 3-BAC'). The resin formulation may also require an accelerator or catalyst to promote the reactivity of the curing agent with the epoxy resin. However, the combination of epoxy resin, hardener, and catalyst may adversely affect the above properties that need to be worked during the HP-RTM molding manufacturing process. Thus, there is a need for fast curing epoxy compositions suitable for use in HP-RTM manufacturing processes that meet low viscosity, fast cure and high resin T_gThe manufacturing requirements of (1). These requirements are addressed by the embodiments of the present disclosure as described below and defined by the claims that follow.

Disclosure of Invention

In a first aspect, an article comprises a cured polymer. The cured polymer has a tensile strength of not less than 10000 psi (68948 kPa) as determined by ISO527-1 (2012). Alternatively, the cured polymer may have a flexural strength of not less than 17000 psi (117211 kPa) as determined by ISO 178 (2010). In addition to tensile strength or flexural strength, the cured article has an elongation at break of at least 2% as determined by ISO527-1(2012) or a flexural strain of at least 4% as determined by ISO 178 (2010).

In a second aspect, the resin composition comprises at least one polymer component in an amount from about 70% to about 98% by weight of the resin composition. The resin composition further comprises a curing component in an amount of from 2% to about 30% by weight of the composition. The curing component may include chemicals having secondary or primary amines. The chemical may further comprise a tertiary amine, an aromatic amine, or an imine. Further, the molecular weight of the free base form of the chemical substance may be greater than 70 g/mol.

In a third aspect, a method includes mixing a curing component and a polymer component to form a resin. The method also includes transferring the resin into a mold. The method may further comprise allowing the resin to cure at a temperature T of less than 120 ℃_cLower cure did not exceed 10 minutes. In addition, the method may further include removing the substantially cured article from the mold. In embodiments, the article has a tensile strength of not less than 10000 psi (68948 kPa) as determined by ISO527-1(2012) or a flexural strength of not less than 17000 psi (117211 kPa) as determined by ISO 178 (2010). Further, the article may have an elongation at break of at least 2% as determined by ISO527-1(2012) or a flexural strain of at least 4% as determined by ISO 178 (2010).

In a fourth aspect, the epoxy resin composition comprises from about 70% to about 95% by weight of the composition of the epoxy component. The epoxy resin may further comprise a curing component in an amount of about 5% to about 30% by weight of the composition. The curing component comprises imidazole. The imidazole may be selected from:

wherein R is₁And R₂Not both hydrogen, and is selected from the group consisting of aminoalkyl, hydroxyalkyl, amino-hydroxyalkyl, and any combination thereof. In addition, the epoxy component and the curing component react together at a temperature of about 100 ℃ to about 130 ℃ to form a substantially cured reaction product in about 10 minutes or less. Even further, the cured reaction product has a tensile strength of not less than 10000 psi (68948 kPa) as determined by ISO527-1(2012) or a flexural strength of not less than 17000 psi (117211 kPa) as determined by ISO 178 (2010). The curing reactant may also have an elongation at break of at least 2% as determined by ISO527-1(2012) or by ISO 178(2010)) A measured flexural strain of at least 4%.

Brief description of the drawings

The embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings.

Figure 1 shows the reaction path for epoxy curing.

Fig. 2 shows the mechanical properties and glass transition temperatures of various epoxy formulations.

Skilled artisans appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of embodiments of the present disclosure.

Detailed Description

The following description is provided in conjunction with the accompanying drawings to assist in understanding the teachings disclosed herein. The following discussion will focus on specific implementations and embodiments of the teachings. This focused discussion is provided to help describe these teachings and should not be construed to limit the scope or applicability of the teachings. However, other embodiments may be used based on the teachings as disclosed in this application.

The terms "comprises," "comprising," "includes," "including," "includes," "having," "has," "having," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a method, article, or apparatus that comprises a list of features is not necessarily limited to only those features but may include other features not expressly listed or inherent to such method, article, or apparatus. Furthermore, unless expressly stated to the contrary, "or" means an inclusive or, and not an exclusive or. For example, either of the following satisfies condition a or B: a is true (or present) and B is false (or not present), a is false (or not present) and B is true (or present), and both a and B are true (or present).

Also, the use of "a" or "an" is used to describe elements and components described herein. This is for convenience only and gives a general sense of the scope of the disclosure. The description is to be understood as including one, at least one, or the singular, as well as the plural, and vice versa, unless the context clearly dictates otherwise. For example, when a single item is described herein, more than one item may be used in place of a single item. Similarly, where more than one item is described herein, a single item may be substituted for more than one item.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The materials, methods, and examples are illustrative only and not intended to be limiting. To the extent not described herein, many details regarding specific materials and processing behaviors are conventional and may be found in textbooks and other sources in composites, polymers, thermosets, and polymer formulations.

As described above, as a first aspect of the disclosed inventive subject matter, the cured polymer may have a tensile strength of not less than 10000 psi (68948 kPa) as determined by ISO527-1(2012) or a flexural strength of not less than 17000 psi (117211 kPa) as determined by ISO 178 (2010). In one embodiment, the tensile strength may be not less than 10500 psi (72395 kPa), such as not less than 11000 psi (75843 kPa), not less than 11300 psi (77911 kPa), not less than 11500 psi (79290 kPa), not less than 11800 psi (81359 kPa), not less than 12000 psi (82738 kPa), not less than 12200 psi (84117 kPa), not less than 12400 psi (85495 kPa), not less than 12600 psi (86874 kPa), or not less than 12800 psi (88253 kPa).

In another embodiment, the flexural strength may be not less than 17500 psi (120659 kPa), such as not less than 18000 psi (124106 kPa), not less than 18500 psi (127554 kPa), not less than 19000 psi (131001 kPa), not less than 19500 psi (134448 kPa), not less than 20000 psi (137896 kPa), not less than 20200 psi (139275 kPa), not less than 20400 psi (140653 kPa), not less than 20600 psi (142032 kPa), not less than 20800 psi (143411 kPa), not less than 21000 psi (144790 kPa), not less than 212000 psi (146169 kPa), not less than 21400 psi (147549 kPa), not less than 21600 psi (148927 kPa), or not less than 21800 psi (150306 kPa).

In further explaining the first aspect, the cured polymer may have an elongation at break of at least 2% as determined by ISO527-1(2012) or a flexural strain of at least 4% as determined by ISO 178 (2010). In one embodiment, the elongation at break may be at least 2.1%, such as at least 2.2%, at least 2.3%, at least 2.4%, at least 2.5%, at least 2.6%, at least 2.7%, at least 2.8%, at least 2.9%, at least 3%, at least 3.2%, at least 3.4%, at least 3.6%, at least 3.8%, at least 4%, at least 4.3%, at least 4.5%, at least 4.8%, at least 5%, at least 5.3%, at least 5.5%, at least 5.8%, or at least 6%.

In another embodiment, the cured polymer may have a flexural strain of at least 4.1%, such as at least 4.2%, at least 4.3%, at least 4.4%, at least 4.5%, at least 4.6%, at least 4.7%, at least 4.8%, at least 4.9%, at least 5%, at least 5.2%, at least 5.4%, at least 5.6%, at least 5.8%, at least 6%, at least 6.3%, at least 6.5%, at least 6.8%, at least 7%, at least 7.3%, at least 7.5%, at least 7.8%, or at least 8%.

In another embodiment, the cured polymer may have a glass transition temperature, T, of at least 120 ℃ as determined by differential scanning calorimetry according to ASTM D7028_gE.g., at least 125 ℃, at least 130 ℃, at least 132 ℃, at least 134 ℃, at least 136 ℃, at least 138 ℃, at least 140 ℃, at least 142 ℃, at least 144 ℃, at least 146 ℃, at least 148 ℃, at least 150 ℃, at least 152 ℃ or at least 154 ℃.

In another embodiment, T_gGreater than the curing temperature T_CuringI.e. the temperature at which the cured polymer is obtained from the mixture of resin, curing component and any other optional additives during processing. In a particular embodiment, T_gAnd T_CuringThe difference between them is at least 10 ℃, such as at least 15 ℃, at least 20 ℃, at least 25 ℃, at least 30 ℃, at least 35 ℃, at least 40 ℃, at least 45 ℃ or at least 50 ℃.

In one embodiment, the cured polymer of the polymer may comprise an epoxy polymer, a polyester, a polyamide, a polyimide, a polyurethane, a polyacrylate, a polyacrylamide, a polyketone, or any combination thereof. In a particular embodiment, the cured polymer consists essentially of an epoxy polymer. In this connection, polymer is understood to be the reaction product of a polymer component and a curing component. For example, an epoxy polymer is understood to be the reaction product of an epoxy component and a curing component.

The polymer component may be present in an amount from about 50% to about 99% by weight of the composition. In one embodiment, the polymer component is present in an amount from about 70% to about 98% by weight of the composition. The polymer component may be a single resin, or it may be a mixture or blend of mutually compatible resins.

When describing the epoxy polymer, the epoxy resin component and the curing component. The epoxy component may be present in an amount from about 50% to about 98% by weight of the composition. In one embodiment, the epoxy component is present in an amount from about 70% to about 95% by weight of the composition. The epoxy resin may be a single resin, or it may be a mixture or blend of mutually compatible epoxy resins.

Suitable epoxy resins include, but are not limited to, phenolic-based difunctional epoxy resins such as 2, 2-bis- (4-hydroxyphenyl) -propane (a/k/a bisphenol a) and bis- (4-hydroxyphenyl) -methane (a/k/a bisphenol F). These phenols can be reacted with epichlorohydrin to form diglycidyl ethers of these polyphenols (e.g., bisphenol a diglycidyl ether, or DGEBA). Polyfunctional epoxy resins, as used herein, describe compounds containing two (i.e., difunctional) or more (i.e., polyfunctional) 1, 2-epoxy groups per molecule. Epoxy compounds of this type are well known to those skilled in the art.

The epoxy component may be an aliphatic epoxy resin, which includes glycidyl epoxy resins and cycloaliphatic (cycloaliphatic) epoxides. Glycidyl epoxy resins include dodecanol glycidyl ether, diglycidyl ester of hexahydrophthalic acid, and trimethylolpropane triglycidyl ether. These resins generally exhibit low viscosities (10-200 mPas) at room temperature and are useful for reducing the viscosity of other resins. Examples of suitable cycloaliphatic epoxides include diepoxides of cycloaliphatic esters of dicarboxylic acids, such as bis (3, 4-epoxycyclohexylmethyl) oxalate, bis (3, 4-epoxycyclohexylmethyl) adipate, bis (3, 4-epoxy-6-methylcyclohexylmethyl) adipate, vinylcyclohexene diepoxide; limonene diepoxide; bis (3, 4-epoxycyclohexylmethyl) pimelate; dicyclopentadiene diepoxide; and other suitable cycloaliphatic epoxides. Cycloaliphatic epoxides likewise exhibit low viscosity at room temperature; however, their room temperature reactivity is rather low, generally requiring high temperature curing with suitable accelerators.

In another embodiment, an epoxy novolac resin (which is a glycidyl ether of a novolac resin) may be used as the multifunctional epoxy resin in accordance with the present disclosure. Suitable epoxy novolac resins include polyepoxide (epoxy phenol novolac resins) and epoxy cresol novolac resins. These are generally high viscosity resins with high epoxy functionality of about 2 to 6, providing high temperature and chemical resistance after curing, but low flexibility.

The viscosity of the epoxy resin composition can be reduced by modifying the epoxy component. The epoxy component may comprise at least one multifunctional epoxy resin and/or one or more monofunctional epoxy resins. Monoepoxides include, but are not limited to, styrene oxide, cyclohexene oxide, and phenol, cresol, tert-butylphenol, other alkylphenols, butanol, 2-ethylhexanol, C₄-C₁₄Glycidyl ethers of alcohols and the like, or combinations thereof. The multifunctional epoxy resin may also be present in solution or emulsion form, wherein the diluent is water, an organic solvent, or a mixture thereof.

Other epoxy resins suitable for use in the present invention include higher functionality epoxy resins such as glycidyl amine epoxy resins. Examples of such resins include triglycidyl-p-aminophenol (functionality 3) and N, N, N, N-tetraglycidyl-4, 5-methylenebisbenzylamine (functionality 4). These resins are of low to moderate viscosity at room temperature, making them easy to handle.

The resin composition further comprises a curing component. In embodiments, the curing component comprises a secondary or primary amine. The curing component may also comprise a tertiary amine, an aromatic amine or an imine. Further, the curing component in free base form may have a molecular weight of greater than 70g/mol, such as greater than 75g/mol, greater than 80g/mol, greater than 85g/mol, greater than 90g/mol, greater than 95g/mol, greater than 100g/mol, greater than 105g/mol, greater than 110g/mol, greater than 120g/mol, greater than 130g/mol, greater than 140g/mol, greater than 150g/mol, or greater than 160 g/mol.

In one embodiment, the curing component may comprise primary, secondary and aromatic amines. In another embodiment, the curing component may comprise two primary amines, one secondary amine and an aromatic amine. In another embodiment, the aromatic amine comprises a moiety selected from the group consisting of imidazole, pyridine, pyrimidine, pyrazine, benzimidazole, thiazole, oxazole, pyrazole, isoxazole, isothiazole, or any mixture thereof.

In another embodiment, the curing component is selected from:

in the above imidazole, R₁And R₂May not be simultaneously hydrogen. In one embodiment, R₁And R₂May be selected from: aminoalkyl, hydroxyalkyl, amino-hydroxyalkyl, or any combination thereof.

In another embodiment, the curing component may be selected from:

or any of the enantiomers or diastereomers described above. For the inclusion of R₃Structure of the radical, radical R₃May be selected from: hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl orAnd (4) isobutyl. In another embodiment, the setting component consists essentially of histamine. In another embodiment, the curing component consists essentially of 2- (2-aminoethyl) imidazole.

In fig. 1 of the present disclosure, an exemplary epoxy curing reaction is shown. More specifically, histamine is shown as the curing component. As can be seen from the first step, primary amines are the most reactive and react with the two epoxy groups of the epoxy resin. Thus, the primary amine becomes a linker in the first chain of the epoxy polymer backbone. In the second step, the secondary amine of the imidazole ring is reacted with an epoxy group. Thus, the secondary amine becomes a terminal unit of the second epoxy polymer chain. As can be seen from the third step, as the reaction proceeds, the heterocyclic aromatic amine becomes reactive and reacts with the epoxy group, thereby generating a zwitterion. The zwitterionic alkoxide may actually further react with another epoxy group, thereby further catalyzing polymerization of the epoxy group itself. For the sake of clarity, chain transfer, i.e. the transfer of the activity of the growing polymer chain to another molecule (P. + XR → PX + R.) -is omitted in the polymerization process but it may also contribute to the polymerization of the epoxy groups themselves. Since the epoxy system is already crosslinked before the third step (aromatic amine reaction), the polymerization reaction starting from aromatic amines and comprising alkoxides can actually grow further and link all unreacted epoxy groups directly or by a chain transfer process, or even react with another polymer chain by hydrogen bonding or nucleophilic substitution of hydroxyl groups, which results macroscopically in a more robust polymer material. Similar hardeners, such as 1- (aminopropyl) imidazole ('API'), have no secondary amines that react with the epoxy groups and therefore lack the potential to crosslink the epoxy groups before they homopolymerize.

Thus, the presence of protic amino groups and aprotic imino or aromatic amines in the curing component has an effect on the tensile and flexural properties of the resulting cured polymer. Furthermore, the distance between the protic and aprotic nitrogen can affect the final crosslinking reactivity of the curing agent, as this distance determines the extent to which the polymer chains formed by the protic amine are close to each other. Thus, in one embodiment, the primary amine of the curing component may be within a radius of less than 100nm, less than 90nm, less than 80nm, less than 70nm, less than 60nm, or less than 50nm from the secondary amine nitrogen. In another embodiment, the aromatic amine or imine can be within a radius from the secondary amine nitrogen of less than 50nm, less than 40nm, less than 30nm, less than 20 nm.

In another embodiment, the curing component may comprise the product of a natural substance. In a particular embodiment, the curing component may be selected from:

or any of the enantiomers or diastereomers described above.

Where a polymer component is specified, in one embodiment, the polymer component may be selected from: an epoxy component, a carboxylic acid ester component, a carboxylic acid anhydride component, an isocyanate component, an acrylonitrile component, a urea component, an aldehyde component, a ketone component, or any combination thereof. In another embodiment, the polymer component and the curing component react together at a temperature of from about 90 ℃ to about 140 ℃ in less than 10 minutes to substantially form a cured polymer. In another embodiment, they react together at a temperature of from about 100 ℃ to about 135 ℃ in less than 8 minutes, less than 6 minutes, less than 5 minutes, or less than 4 minutes to substantially form a cured polymer.

Thus, the method includes mixing a curing component and a polymer component to form the resin. The method also includes transferring the resin into a mold. The method may further comprise curing at a temperature T of less than 120 ℃_cThe resin is cured for no more than 10 minutes. This is achieved byIn addition, the method may further include removing the substantially cured article from the mold. In embodiments, the article has a tensile strength of not less than 10000 psi (68948 kPa) as determined by ISO527-1(2012) or a flexural strength of not less than 17000 psi (117211 kPa) as determined by ISO 178 (2010). Further, the article may have an elongation at break of at least 2% as determined by ISO527-1(2012) or a flexural strain of at least 4% as determined by ISO 178 (2010).

In one embodiment, the curing component may be added in an amount less than the theoretical stoichiometry required to react all of the reactive sites of the polymer component with the curing agent. This can be understood from figure 1 and with reference to the foregoing description. The epoxy functionality can be homopolymerized due to the zwitterion generated by the aromatic amine.

In one embodiment, the curing component may be added in an amount no greater than 90% of the theoretical stoichiometry, such as no greater than 80%, no greater than 70%, no greater than 60%, no greater than 55%, no greater than 50%, no greater than 45%, no greater than 40%, no greater than 35%, no greater than 30%, or no greater than 25% of the theoretical stoichiometry.

In another embodiment, the polymer component has several reactive functionalities n_rE.g. epoxy functional groups, and the curing component has a curing functionality n_cSuch as primary amines (factor 2), secondary amines (factor 1) and heterocyclic aromatic-amines (factor 1). For 100% of theoretical stoichiometry, n_r＝n_c. In one embodiment of the present disclosure, the resin has an n of no greater than 0.98, no greater than 0.95, no greater than 0.9, no greater than 0.85, no greater than 0.8, no greater than 0.75, no greater than 0.7, no greater than 0.65, no greater than 0.6, no greater than 0.55, no greater than 0.5, no greater than 0.45, no greater than 0.4, no greater than 0.38, no greater than 0.36, no greater than 0.34, no greater than 0.32, no greater than 0.30, no greater than 0.28, no greater than 0.26, no greater than 0.24, no greater than 0.22, no greater than 0.2, no greater than 0.18, or no greater than 0.16_c:n_rThe ratio of (a) to (b).

In another embodiment, the resin may further comprise reinforcing fibers. In one embodiment, the reinforcing fibers may be selected from: glass fibers, fiberglass, silicon carbide fibers, silicon carbide (disilicon carbide) fibers, carbon fibers, graphite fibers, boron fibers, quartz fibers, alumina fibers, carbon nanotubes, nanocomposite fibers, polyaramide fibers, poly (p-phenylene benzobisoxazole) fibers, ultra high molecular weight polyethylene fibers, high and low density polyethylene fibers, polypropylene fibers, nylon fibers, cellulosic fibers, natural fibers, biodegradable fibers, or combinations thereof.

Experimental part:

figure 2 discloses tensile strength and glass transition temperature results for epoxy polymers (from Epon 828) containing different phr of histamine. It can be seen that histamine can cure epoxy resins at 6-16 parts per hundred (phr), below the theoretical (stoichiometric) 20phr, with excellent thermo-mechanical properties, equal to or better than those at the theoretical phr (as measured by T)_gTensile and flexural strength, and hardness). When used with Epon 828, 7.88phr (40% of theoretical phr) of histamine gave a T_gEpoxy resin at 150 ℃, tensile strength of 87.5MPa, flexural strength of 152.5MPa, strain (elongation) of 5.1% and 6.3%, respectively.

For comparison-a typical value for Jeffamine D230 at phr 32 (D230 used was about 4 times histamine) was: a tensile strength of 76MPa and a flexural strength of 93 MPa. The explanation for this abnormal behavior of histamine is the equilibrium mechanism of histamine action between cross-linking of epoxy (the normal epoxy curing mechanism) and homopolymerization. Histamine is effective as a catalyst for prepreg formulations when used in conjunction with 2-cyanoguanidine (DICY) and prepreg epoxy resins to replace the commonly used 2-methylimidazole. The histamine powder can be used in a one-component epoxy resin.

Histamine can be isolated in solid form and ground to a fine powder due to its melting point of 84 ℃. Basic experiments were performed: this fine powder can be mixed at room temperature with Epon 828 epoxy resin having a histamine phr of 19.7, resulting in a paste that remains a viscous liquid for an extended period of time; much longer than when histamine is used in liquid form (molten histamine or warm adduct). The time for which the paste remains liquid depends on the temperature, and at lower temperatures the paste remains viscous for longer. When stored at room temperature, the paste solidifies the next day. There is a need for a one-part epoxy adhesive that does not require weighing and mixing of the components. Histamine powder has the ability to make such a binder.

Experiment 1: synthesis of histamine on a 500g Scale

Histamine dihydrochloride (905g, 4.92 moles) was dissolved in 825g of water and 786.7g of 50% sodium hydroxide (9.84 moles) was added. The pH of the solution was 10. The reaction mixture was concentrated on a rotary evaporator and 750mL of Isopropanol (IPA) was added. The sodium chloride was filtered off and another 750mL portion of IPA was added. The mixture was concentrated and placed under high vacuum overnight. The product crystallized out as a solid in a yield of 470g (86%). Similarly, the process can be carried out using an isopropanol solution of sodium carbonate or essentially any inorganic base.

Experiment 2: histamine-13

The melting point of histamine is 84 ℃. When isolated as the free base, it crystallizes as large molten crystals. The crystals can be ground to form a powdered solid. Histamine powder is hygroscopic, but the ground histamine can be stored for a long time in a dry and sealed container. For the liquid formulation, an adduct ("histamine-13") was developed with a molar ratio of 13:1 to Epon 828 (DGEBA). This form remains a viscous liquid for long periods of time and can be easily reheated to a workable liquid.

Experiment 3-10: epoxy resin thermoset samples

Cured epoxy thermoset plastic disks were prepared using the above-described molten or warm histamine-13 and additionally Epon 828 (DGEBA). Parts per 100 parts of epoxy resin (PHR) histamine were calculated and corresponding amounts of histamine were flash mixed with epoxy resin for 5 minutes at 2500rpm in a disposable container using a double asymmetric centrifugal laboratory mixer system. This step eliminates air bubbles and/or produces a homogeneous suspension of the components (for pre-soak evaluation). The samples were cured in an epoxy sample pan or aluminum mold (dimensions 10 inch x10 inch x0.25 inch). The sample was decanted and left overnight at Room Temperature (RT). The partially cured samples were then post-cured in an oven at 125 ℃ for 10 minutes to 1-3 hours, unless otherwise noted.

Table 1 discloses the T corresponding to histamine content after 10 minutes of post-curing_gThe relationship of the values.

Table 1: histamine content and T_g。

As can be seen from Table 1, at low histamine concentrations (experiments 4 and 5), the resulting thermosets produced T_gSimilar to T at approximately the stoichiometric combination (experiments 9 and 10, 19.7phr being 100% of stoichiometry)_gAnd between them, T_gExperiences a minimum as histamine concentration increases, however, T_gNever dropping below 132 c. In addition, all of the formulations in table 1 exhibited hardness approaching the range of 88 to 89D for the prepared samples determined using a Shore D durometer.

Experiments 11-15: mechanical Properties at different phr

The mechanical properties of histamine cured panels (10 inches x10 inches x0.25 inches) were evaluated according to ISO527 tensile test and ISO 178 flexural test at phr levels of 5.91, 7.88, 9.85, and 15.8 (30%, 40%, 50%, and 80% of theoretical phr). The panels were prepared as described above. After curing, they were uniformly colored and did not have any fractal pattern except at the theoretical phr of 19.7.

A plurality of samples were cut from the plate and a force was applied to determine the force required to break the sample and the extent to which the sample stretched, elongated or bent. The data are shown in Table 2 (nd-not determined).

Table 2: tensile and flexural properties of the thermoset at various histamine levels.

Unexpectedly, the amount of histamine is in the range of less than 100% of the theoretical phr, more specifically not less than 30% phr and less than 100% phr, the samples show very high tensile and flexural strength. The histamine cured Epon 828 epoxy board shows high strength mechanical properties in the phr range of 40-80% of theoretical phr. At 40% of the theoretical phr (7.88), the tensile strength measured is highest: 87.5MPa (12692 psi) and an elongation at break of 5.1%. The flexural strength measured at 40% of theoretical phr is also highest, namely 152.48MPa (22118 psi) and 6.3% strain at break. At both ends of the phr test range, i.e.: above 80% and below 40% of the theoretical phr, the strength of the histamine cured epoxy panel decreased significantly.

Experiments 16 and 17: histamine as a component of prepreg materials

Prepregs generally consist of three components: 1) a high viscosity epoxy resin; 2) a curing agent; and 3) a curing accelerator. Epotec's YDPN 638 (semi-solid phenol novolac epoxy) was used as the resin, 7% Evonik's dichyanex 1408 (2-cyanoguanidine, DICY) was used as the hardener, and 1% molten histamine (experiment 16) or 1% Evonik's impact AMI2 (2-methylimidazole) was used as the accelerator. Histamine was evaluated as a substitute for 2-methylimidazole in prepregs.

Both experiments investigated that the prepreg formulation produced a white viscous paste after warm mixing using a high shear dispensing impeller. After cooling, the formulation remained viscous and rubbery for more than one week at room temperature. The cure speed of the prepreg formulations was tested in an oven at three different temperature and time settings as shown in table 3. The conditions selected are based on those typically used for prepregs. As seen in the results below, both formulations did not cure sufficiently when cured at 110 ℃, but cured rapidly at 120 ℃.

As can be seen in table 3, histamine has catalytic properties comparable to 2-methylimidazole. The presence of primary amine groups in histamine does not affect catalytic performance or affect storage or premature polymerization.

Table 3: histamine as a catalyst

Experiments 18-20: additional amines with epoxy resins

A mixture of epoxy resin and histamine-like amine was prepared using a separate hardener as listed in table 4 with Epon 828. To achieve the catalytic effect, i.e. anionic homopolymerization of Epon 828, the amount studied corresponds to 8% of the theoretical PHR.

The histamine-closely related L-histidinol is difficult to formulate due to its high polarity and low solubility in Epon 828, and the T obtained_gBelow 60 ℃.5, 6-dimethylbenzimidazole behaves similarly to histamine. Despite its high melting point (205 ℃), it can still catalyze the homopolymerization of Epon 828 due to its solubility. As expected based on previous studies, in the presence of 5, 6-dimethylbenzimidazole, the homopolymerization was started at 120-130 ℃ and the T of the obtained epoxy resin was_gThe temperature was 158 ℃.

Table 4: various imidazoles

Experiments 21-22: conventional amine hardener vs Histamine in epoxy resins

Cured epoxy thermoset trays were prepared using Jeffamine D230 and histamine, and additionally Epon 828 (DGEBA). Parts per 100 parts epoxy Jeffamine D230 (PHR) is 30.5 and histamine PHR is 7.5. The mixture was simply mixed and poured into a mold. The samples were then placed in a rheometer to determine pot life.

Rheometer arrangement

The instrument comprises the following steps: DHR-1(TA Instruments)

A fixing device: 25mm parallel plates with drip channel (w/clip channel)

Normal force control: 0.1N, 0.5N sensitivity

And (3) a test mode: oscillatory time scanning

Sampling interval: 25s/pt

Strain: 0.1 percent of

Angular frequency: 1rad/s

The size of the gap: 500um

Sample preparation: the instrument was preheated to the desired temperature prior to injection of the premixed sample. A stopwatch was used to measure the time (typically 30-40 seconds) from injection of the sample on the preheated instrument to the start of data collection. The gel time and shelf life values were corrected to correct for this time.

Pot life is defined as the time it takes for the initial viscosity measured at mixing to double. The time was started from the time of product mixing and, unless otherwise stated, was measured at room temperature (23 ℃). As for the gel time, it is the time taken until the resin becomes a wireform or gel-like. The gel time is measured at elevated temperature. Finally, cure time refers to the time it takes for the resin to mix at a temperature until fully cured. The following table discloses the results of the measurements.

Table 5: comparison of Jeffamine and Histamine

Pot life/sec measurements at the indicated curing temperature

T shown_gIs obtained under optimum curing conditions

As shown in table 5, histamine cured faster than the conventional hardening agent Jeffamine D230. More unexpectedly, at a cure temperature of 140 ℃, the cure kinetics were onlyThe reference hardener is part of the set kinetics. Fast curing times are associated with shorter cycle times during fabrication, thus reducing costs and increasing throughput. In addition, histamine achieved faster kinetics while also providing higher T_g。T_gOne advantage of higher than curing temperatures is that the mold can be quickly demolded without cooling, which also facilitates faster manufacturing. Furthermore, high T_gThe material can be applied to high-temperature environment. For example, T may be_gTall plastics are placed closer to the heat source or combustion engine.