阅读说明：本技术 含磺胺的环氧树脂组合物 (epoxy resin composition containing sulfanilamide ) 是由 T·A·莫利 R·科尼哲 L·洛蒂 N·杰立卡 Z·西克曼 M·赖默斯 于 2018-04-11 设计创作，主要内容包括：一种新型含磺胺的环氧树脂组合物,其能够快速固化,而不会对玻璃化转变温度或机械性能造成负面影响。(A novel sulfonamide-containing epoxy resin composition that cures rapidly without adversely affecting glass transition temperature or mechanical properties.)

1. A liquid-based curing agent composition comprising a catalyst, an amine-based hardener, and a sulfonamide having the following chemical structure

2. A hardener composition in accordance with claim 1 wherein said catalyst comprises at least one of 2-phenylimidazole and 1, 4-diazabicyclo [2.2.2] octane.

3. The hardener composition of claim 1, wherein the amine-based hardener comprises triethylenetetramine.

4. The hardener composition of claim 1, further comprising a mixture of primary and secondary amine compounds.

5. A hardener composition in accordance with claim 4 wherein said mixture comprises an aminocyclohexanealkylamine.

6. The hardener composition of claim 1, comprising, based on the total weight of the hardener composition, from 0.1 to 15 weight percent catalyst; 1 to 100 weight triethylenetetramine; and 0.1 to 60% by weight of a sulfonamide.

7. The hardener composition of claim 6, further comprising from 5 to 60 weight percent of a mixture of primary and secondary amine compounds.

8. An epoxy-based resin composition comprising i) one or more epoxy resins; and ii) a hardener composition comprising a sulfonamide.

9. A composite article comprising the hardener composition of claim 1.

10. The composite article of claim 9, further comprising one or more impact modifiers, internal mold release agents, reactive diluents, coalescents, pigments, dyes, particulate fillers, extenders, tackifiers, antioxidants, and wetting agents.

Background

Fast curing performance windows are critical for mass production of carbon and fiberglass based applications, such as automotive body structural components, and other composite applications. For example, when considering the application of glass fiber suspensions with respect to vehicle body structures, the resin composition generally has a large impact on the mechanical properties of the final composite, and therefore the resin composition should be carefully designed to obtain good mechanical properties in the composite while maintaining a high cure speed.

A well-known approach to improving thermal and mechanical properties in epoxy-based compositions is to include cycloaliphatic or aromatic amine-based compounds in the hardener composition. While this can improve many aspects of performance, such as producing materials with higher glass transition temperatures and improved tensile and shear properties, the cure speed is generally therefore significantly extended. In addition, aromatic amines generally have problems with EH & S and often have a high degree of colorability. When in solid form, aromatic amines can be difficult to dissolve, especially when liquid-based compositions are desired in processing applications such as Resin Transfer Molding (RTM) and Liquid Compression Molding (LCM). To counteract the negative effect on cure time, compounds known as "accelerators" may also be included in the resin composition. These are compounds that increase the rate of catalytic reactions, but are not catalysts per se. For this reason, accelerators based on tertiary amines, phenols or carboxylic acids are very effective and are often used in amine-based compositions. However, its presence may adversely affect thermal and mechanical properties, i.e., lower glass transition temperature and lower tensile and shear properties.

Disclosure of Invention

The problem has been solved by using a hardener composition containing sulfonamide molecules as accelerators, which surprisingly found that the sulfonamide molecules dissolve well in triethylenetetramine (TETA), resulting in the required liquid curing agent, which can be used on ordinary injection equipment. When a solution of TETA and sulfanilamide is further mixed with a suitable catalyst and optionally a cycloaliphatic amine moiety to form a hardener and then reacted with an epoxy resin, a significantly faster curing epoxy composition can be obtained without affecting the mechanical properties in terms of glass transition temperature or interlaminar shear strength (ILSS).

The hardener composition of the present invention has a viscosity of about 0.1 to 100,000 mpa.s; preferably from about 1 to 60,000 mpa.s; more preferably from about 1 to 30,000 mpa.s; and most preferably from about 1 to 10,000 mpa.s. The viscosity is measured by: the samples were placed in a rheometer (MCR301, Anton Paar) equipped with parallel plates (diameter 25mm, gap 1mm) maintained at isothermal conditions at 25 ℃ and then at 10s^-1Rotational speed of [1/s ]]The measurement is performed.

Drawings

Figure 1 shows the effect of sulfonamide on Tg, gel time and ILSS.

Detailed Description

The present invention relates to curable compositions comprising heat resistant fibers, such as carbon fibers, glass fibers, or mixtures thereof; the following two-component resin mixture: (i) one or more epoxy resin compositions (such as bisphenol a or bisphenol F diglycidyl ether epoxy resins), and (ii) a curing agent composition comprising a combination of: a) hardener (such as triethylenetetramine (TETA)), b) 0.1 to 15 wt% catalyst (such as 2-phenylimidazole (2-PI) or 1, 4-diazabicyclo [2.2.2] octane ("DABCO"), based on the weight of TETA, c) 0.1 to 60 wt% accelerator (e.g. a sulfonamide, such as one available from Hunan Chemicals BV), and d)5 to 60 wt% cycloaliphatic amine, based on the weight of TETA. It has been found that the compositions of the present invention are capable of curing at high speeds, even below 60 seconds, while providing high glass transition temperatures in excess of 120 ℃, and yielding composites with improved interlaminar shear properties from the compositions relative to composites prepared by the more widely used fast curing epoxy resin systems.

Many different epoxy resin compositions may benefit from the present invention. For example, epoxy resin a, which is a diglycidyl ether of bisphenol a, has an epoxy equivalent weight of 180 grams/equivalent, and contains about 0.5 weight percent of a mono-hydrolyzable species, as shown in the examples, can be used as the epoxy resin composition to be mixed with the hardener composition of the present invention.

As noted above, there are a number of widely used aromatic-based amine hardener compositions. They all have some undesirable characteristics such as insolubility in other compatible chemicals and unfavorable EH & S profiles. Sulfonamides containing a chemical structure as shown in structure I below are generally considered to have a low EH & S profile and have been found to be highly soluble in triethylenetetramine, resulting in formulations that, when used to make composite articles, exhibit improved mechanical properties while at the same time exhibiting the ability to achieve fast cure times.

Table 1 illustrates the comparison of sulfonamides with some other aromatic amines.

TABLE 1 comparison of sulfonamides with other commonly used aromatic curing agents.

In one embodiment of the present invention, the hardener composition comprises, based on the weight of the hardener composition, about 1 to 100 weight percent, preferably 10 to 90 weight percent, and more preferably 20 to 90 weight percent TETA; about 0.1 to 60 wt%, preferably 0.5 to 50 wt%, and more preferably 1 to 40 wt% sulfonamide; about 5 to 60 weight percent, preferably 5 to 50 weight percent, and more preferably 10 to 40 weight percent, of isophorone diamine ("IPDA") or other cycloaliphatic amine; and a catalyst, such as 1, 4-diazabicyclo [2.2.2] octane ("DABCO"), in an amount of from 0.1 to 15 wt%, preferably from 1 to 15 wt%, and more preferably from 1 to 10 wt%.

The hardener composition of the present invention may also contain a mixture of primary and/or secondary amine compounds. Aminocyclohexylalkylamines constitute about 5 to 60 weight percent, preferably 5 to 50 weight percent, and more preferably 10 to 40 weight percent of the weight of primary and/or secondary amino compounds in the curing agent composition. Aminocyclohexylalkylamines are substituted cyclohexanes having both amino and aminoalkyl substituents on the cyclohexane ring. Among the suitable aminocyclohexane alkylamine compounds are those represented by structure II:

wherein R is¹Is C₁-C₄Alkyl, each R is independently hydrogen or C₁-C₄alkyl, and m is a number from 1 to 8. Each R group in structure II is preferably independently hydrogen or methyl, and R¹preferably methyl. In Structure II, - (CR)₂)_m-NH₂the group may be ortho, meta or para with respect to the amino group bonded directly to the cyclohexane ring. -NH in Structure II₂And- (CR)₂)_m-NH₂The groups may be in cis or trans positions relative to each other. In Structure II, except for-NH which is inert to the reaction of the epoxy amine₂、-R¹And- (CR)₂)_m-NH₂The cyclohexane carbon atom may contain a substituent in addition to the group. The preferred initiator compound corresponding to structure I is cyclohexane methylamine, 4-amino-alpha, 4-trimethyl- (9Cl), also known as p-menthane-1, 8-diamine or 1, 8-diamino-p-menthane.

a second aminocyclohexylalkylamine corresponds to structure III:

R, R therein₁And m is as previously defined. As in structure II, each R group in structure III is preferably independently hydrogen or methyl, and R is¹preferably methyl. In structural formula III, - (CR)₂)_m-NH₂The group may be ortho, meta or para with respect to the amino group bonded directly to the cyclohexane ring. -NH in Structure III₂And- (CR)₂)_m-NH₂The groups may be in cis or trans positions relative to each other. In Structure III, in addition to the-NH groups shown₂、-R¹And- (CR)₂)_m-NH₂In addition to the groups, the cyclohexane carbon atom may also contain inert substituents. A particularly preferred initiator compound corresponding to structure III is 5-amino-1, 3, 3-trimethylcyclohexanemethylamine (isophoronediamine).

As another aspect, the present invention also provides a resin composition comprising, all based on the total weight of the resin composition:

1)1 to 100 weight percent, preferably 30 to 100 weight percent, and more preferably 40 to 100 weight percent epoxy resin a which is a diglycidyl ether of bisphenol a, has an epoxy equivalent weight of about 180 grams/equivalent, and contains about 0.5 weight percent of a mono-hydrolyzable species;

2) From 1 to 100% by weight, preferably from 10 to 80% by weight, and more preferably from 20 to 70% by weight, of an epoxy resin B which is a diglycidyl ether of bisphenol A having 15% core-shell rubber particles and an EEW of-180 g/eq, available from Lin Corp as FORTEGRA^TM301, commercial purchase;

3)1 to 100 weight percent, preferably 10 to 80 weight percent, and more preferably 20 to 70 weight percent epoxy resin C which is a diglycidyl ether of bisphenol a containing 25 weight percent core shell rubber particles relative to the diglycidyl ether of bisphenol a, having an EEW of 180 grams per equivalent, commercially available from bells corporation (Kaneka Corp.) as Kane Ace MX-170;

4)1 to 100 weight percent, preferably 10 to 90 weight percent, and more preferably 20 to 80 weight percent epoxy resin D which is a diglycidyl ether of bisphenol F having an epoxy equivalent of about 171 grams per equivalent;

5)1 to 100 weight percent, preferably 10 to 90 weight percent, and more preferably 20 to 80 weight percent epoxy resin E which is a mixture of diglycidyl ether of bisphenol F and diglycidyl ether of bisphenol a resin having an epoxy equivalent weight of about 172 grams/equivalent;

6) From 1 to 100 weight percent, preferably from 10 to 90 weight percent, and more preferably from 20 to 90 weight percent TETA having an AHEW value of 24.4 grams/equivalent, commercially available from The Dow Chemical Company;

7)0.1 to 15 weight percent, preferably 1 to 15 weight percent, and more preferably 1 to 10 weight percent 2-phenylimidazole ("2-PI"), CAS number 670-96-2, commercially available from Hunan chemical company;

8)0.1 to 15 wt%, preferably 1 to 15 wt%, and more preferably 1 to 10 wt% triethylenediamine or DABCO, CAS 280-57-9; commercially available from Air Products corporation (Air Products);

9)0.1 to 60 wt%, preferably 0.5 to 50 wt%, and more preferably 1 to 40 wt% of a sulfonamide commercially available from chemical company, Hunan.

Other common chemicals may also be used as other functional components or in place of the compounds listed above. One example is the commonly used cycloaliphatic amine, such as 4,4' -methylenebis (cyclohexylamine), CAS 1761-71-3, available from air products as Amicure^TMPACM ("PACM") is commercially available.

Typical epoxy resin compositions may also contain some fillers or other functional chemicals for any intended application.

The invention is further illustrated by the following non-limiting examples.

AHEW means the amount in grams of amine that produces one molar equivalent of hydrogen in the reaction as measured by titration using ASTM D2074-07 (2007).

As used herein, "EEW" or "epoxy equivalent" means the use of a Metrohm 801Robotic USB sample processor XL and two 800Dosino^TMThe amount in grams of epoxy resin that produces one molar equivalent of epoxy groups in the reaction is determined by a dosing device (Metrohm USA, Tampa, FL). The reagents used were perchloric acid and tetraethylammonium bromide in 0.10N acetic acid. The electrode used for the analysis was 854Iconnect^TMelectrodes (Switzerland). For each sample, 1g of the dispersion was weighed into a plastic sample cup. Then, 30mL of Tetrahydrofuran (THF) was first added and mixed for 1 minute (min) to break the shell on the dispersion. Next, 32mL of glacial acetic acid was added and mixed for another 1min to completely dissolve the sample. The sample is then placed on an autosampler and all relevant data (e.g., sample number, sample weight) is added to the software. From here the start button is clicked to startAnd (4) titrating. Thereafter, 15mL of tetraethylammonium bromide was added, and then perchloric acid was slowly added until the potential endpoint was reached. After the potential endpoint is reached, the software will calculate the EEW value based on the amount of sample and perchloric acid used.

"DSC glass transition temperature Tg" means the glass transition temperature of a given material. Dynamic DSC for determining T of compositions_gthe value is obtained. To measure the glass transition temperature, the sample is first heated from 25-200 ℃ at a ramp rate of +20 ℃/min. The sample was held isothermal for three minutes at 220 ℃, cooled to 25 ℃ at a ramp rate of-20 ℃/min, held isothermal for three minutes at 25 ℃, then reheated to 220 ℃ at a ramp rate of +20 ℃/min, held isothermal for 3 minutes at 220 ℃, and cooled to 25 ℃ at a ramp rate of-20 ℃/min. T is_gInitiation and T_gThe midpoint was determined from the second heating section.

To demonstrate the advantages of the present invention, a hot plate experiment was performed. The gel time and demold time were evaluated according to the following cure evaluation test: the epoxy resin (preheated to about 40 c) and hardener mixture (about 25 c) were brought together in the desired ratio and then mixed for 30 seconds. The resulting mixture was poured onto a hot plate preheated to 90 or 130 ℃ to form a liquid dish on the surface of the plate. Time was measured from the point where the mixture contacted the hot plate surface. When the mixture was cured, the hot plate was maintained at 90 or 130 ℃. A line is periodically scribed through the liquid pan using a wooden toning knife or similar blade. Gel Time (GT) is the time at which the liquid material no longer flows towards the score line. Demold time (DMT) is the time after pouring at which time the tray can be removed from the hot plate surface as a solid using a toning knife or similar blade.

Interlaminar shear Strength (ILSS) measurement in a force gaugeRun above and measured by a three-point bending test according to EN ISO 14130. According to the norm, σ is determined at the maximum stress at failure or at the end of the test_m。

TABLE 2 influence of sulfonamides on Tg, gel time and ILSS

As shown in fig. 1 and table 2, comparative example 1 shows the characteristics achieved by reacting epoxy resin a with a representative hardener formulation containing the aliphatic amine triethylenetetramine (TETA), cycloaliphatic amine (4,4' -methylenebis (cyclohexylamine)), and triethylenediamine catalyst in the amounts shown in table 2. Glass fiber composite parts made from these resin compositions were made using a wet compression (LCM) process and a preform consisting of 4 layers of 3BW3030 unidirectional glass fibers.

It can be concluded that according to the invention examples 1 and 2 containing sulfonamides, a significantly faster gel time can be obtained without any loss of thermal or mechanical properties in the composite article. The effect is further confirmed by comparing example 2, in which a higher content of cycloaliphatic amine is used. Inventive examples 3 and 4 again demonstrate that faster gel times can be achieved by the addition of sulfonamide without degrading other key performance attributes. The increased gel time and cure speed of these compositions, which exhibit higher thermal and mechanical properties, can be particularly useful in composites requiring higher performance but requiring high volume production.

Additional inventive and comparative examples were prepared to further demonstrate the effectiveness of the invention, as shown in tables 3 and 4, and table 4 summarizes the details of the various compositions tested. Carbon fiber composite parts made from these resin compositions were produced using a wet compression (LCM) process and a preform consisting of 6 layers of DOWAXSA CL 300E-10B unidirectional carbon fibers.

Table 3: formulations and results of comparative examples and inventive examples

Comparative example a in table 3 lists the performance characteristics of an epoxy system in which DABCO has been used as the catalyst component, while DABCO catalyst in comparative example B has been replaced with 2-phenylimidazole, providing a higher glass transition temperature, as described in U.S. provisional patent application No. 62/341246 ("the 246 application"), filed 2016, 5, 25, which is incorporated herein by reference in its entirety. Thus, inventive examples a and B are equivalent compositions to comparative examples a and B, respectively, the only difference being the addition of a sulfonamide to the composition shown in table 3. All compositions were tested by making carbon fiber composite parts with a 1:1 stoichiometric ratio of epoxy to amine functional groups. It should be noted that by adding a sulfonamide to these compositions, the gel time remained relatively constant (an important feature of mold filling and fiber wetting) and the interlaminar shear strength (ILSS) improved while maintaining or improving the glass transition temperature (comparative example a versus inventive example a) with a constant cure time of 120 seconds.

In order to improve the ILSS of comparative example a over the ILSS of inventive examples a and B while maintaining high glass transition temperature and reaction speed, other more well known methods were investigated. These measures included the addition of core shell rubber particles (comparative examples C and D), and the evaluation of resins by replacing resins (comparative examples E and F) with diglycidyl ethers of bisphenol a resins used in comparative example a and inventive example B.

With the addition of core shell rubber particles, two types from different suppliers were evaluated in comparative examples C and D, respectively. Neither of these two approaches was found to have a beneficial effect on ILSS performance of the final composite a77yd, or resulted in a decrease in ILSS while maintaining the glass transition temperature (comparative example C) or maintaining ILSS but decreasing the glass transition temperature (comparative example D).

To improve the ILSS of comparative example a relative to the ILSS of inventive examples a and B while maintaining high glass transition temperature and reaction speed, additional alternative epoxy resins were evaluated as shown in comparative examples E and F. Specifically, it is well known that bisphenol F based resins, particularly resins having low functionality, increase the flexibility of the resin system, and in comparative example E, a pure bisphenol F based resin is used, whereas in comparative example F, a low functionality novolac resin is used. It is noted from comparative examples E and F that an improvement in ILSS was found in both cases. However, the use of these epoxy resins causes a significant reduction in the glass transition temperature of the manufactured material.

When comparing comparative examples a-F and inventive examples a and B, it should be noted that the addition of sulfonamide showed improved ILSS and at least maintained glass transition temperature and cure speed. In addition, the compositions and methods would benefit from liquid-based hardeners, since sulfonamides were found to be soluble in triethylenetetramine.

Composite articles containing the hardener composition of the present invention may also comprise one or more impact modifiers, internal mold release agents, reactive diluents, coalescents, pigments, dyes, particulate fillers, extenders, tackifiers, antioxidants, and wetting agents as may be conventionally selected by one of ordinary skill in the art.