Cure accelerator for anaerobic curable compositions

Abstract

The present invention relates to an anaerobic curable composition comprising: a) a (meth)acrylate component; b) a first curing agent; c) a second curing agent; and d) a curing accelerator comprising 2-(N-ethylanilino)ethanol and / or 1,2,3,4-tetrahydrobenzo(H)quinolin-3-ol. The anaerobic curable composition of the present invention can be used in adhesives, sealants, threadlocks, and retainers.

Description

[Technical field]

[0001] FIELD OF THEINVENTION The present invention relates to anaerobic curable (meth)acrylate compositions with improved sustainability, health and safety profiles. [Background technology]

[0002] Technical background Anaerobic technology is the most widely used in the consumer electronics industry because it provides improved equipment reliability, time savings, cost reduction, and improved process safety. Anaerobic adhesives are one-component (1k) systems containing esters of acrylic or methacrylic acid, which cure by a redox-initiated free radical mechanism driven by accelerators and initiators. The term anaerobic indicates that polymerization occurs in the absence of air. Typical anaerobic adhesives comprise (meth)acrylate monomers and / or (meth)acrylate oligomers, stabilizers, shape modifiers, and curing agents such as amines, peroxides, and saccharin.

[0003] Cumene hydroperoxide is widely used as a curing agent in anaerobic products due to its properties such as a self-accelerating decomposition temperature (SADT) of 70 °C and a maximum storage temperature (Ts max) of 40 °C. However, due to the nature of its compound and the cumene impurities present, it is listed as a category 2 carcinogen on safety labels. Similarly, diethyl-p-toluidine (DE-pT) and dimethyl-o-toluidine (DM-oT), which are frequently used and among the most effective curing accelerators in terms of the cure speed and strength development of the composition, have a poor health and safety profile.

[0004] There have been some attempts to replace diethyl-p-toluidine (DE-pT) and dimethyl-o-toluidine (DM-oT) in aerobic curable compositions, but peroxide components such as cumene hydroperoxide are still present in the compositions, and therefore the health and safety profile concerns have not been fully addressed. Summary of the Invention [Problem to be solved by the invention]

[0005] Therefore, there is a need for anaerobic curable compositions that can improve the durability, health and safety profile of the adhesive composition without compromising its technical performance. [Means for solving the problem]

[0006] Summary of the Invention The present invention relates to an anaerobic curable composition comprising: a) a (meth)acrylate component; b) a first curing agent; c) a second curing agent; and d) a cure accelerator comprising 2-(N-ethylanilino)ethanol and / or 1,2,3,4-tetrahydrobenzo(H)quinolin-3-ol.

[0007] The present invention also relates to a cured product of the anaerobic curable composition according to the present invention. The present invention includes the use of the anaerobic curable compositions or cured products according to the present invention in adhesives, sealants, threadlockers, and retainers. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Detailed Description of the Invention In the following text, the present invention will be described in more detail. Each aspect thus described can be combined with other aspects, unless expressly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous.

[0009] In the context of the present invention, the terms used shall be construed in accordance with the following definitions, unless the context indicates otherwise.

[0010] As used herein, the singular forms "a," "an," and "the" include both the singular and plural referents unless the context clearly indicates otherwise.

[0011] As used herein, the terms "comprising," "comprises," and "comprised of" are synonymous with "including," "includes," or "containing," and are inclusive or open-ended and do not exclude additional, unlisted members, elements, or method steps.

[0012] As used herein, the term "consisting of" excludes unspecified elements, components, members or method steps.

[0013] The words "preferred," "preferably," "desirably," and "particularly" are frequently used herein to refer to embodiments of the present disclosure that may afford certain advantages, under particular circumstances. However, the recitation of one or more preferred, preferred, desirable, or particular embodiments does not imply that other embodiments are not useful, and is not intended to exclude such other embodiments from the scope of the disclosure.

[0014] As used throughout this application, the word "may" is used in its permissive, or possible, sense rather than its required sense.

[0015] The recitation of numerical endpoints includes all values ​​and fractions subsumed within the respective ranges, as well as the recited endpoints.

[0016] All percentages, parts, ratios, etc. set forth herein are by weight unless otherwise specified.

[0017] When an amount, concentration, or other value or parameter is expressed in the form of a range, a preferred range, or upper preferred value and a preferred lower value, it is to be understood that any range obtained by combining any upper value or preferred value with any lower value or preferred value is specifically disclosed, regardless of whether the resulting range is expressly stated in the context.

[0018] All documents cited herein are incorporated by reference in their entirety.

[0019] Unless otherwise defined, all terms used in disclosing the present invention, including technical and scientific terms, have the meaning commonly understood by one of ordinary skill in the art to which this invention belongs. As a further guide, definitions of terms are included to better understand the teachings of the present invention.

[0020] The present invention relates to an anaerobic curable composition comprising: a) a (meth)acrylate component; b) a first curing agent; c) a second curing agent; and d) a cure accelerator comprising 2-(N-ethylanilino)ethanol and / or 1,2,3,4-tetrahydrobenzo(H)quinolin-3-ol.

[0021] The applicant has found that the use of a cure accelerator, particularly comprising a combination of tert-butylperoxy-3,5,5-trimethylhexanoate and 2-(N-ethylanilino)ethanol and / or 1,2,3,4-tetrahydrobenzo(H)quinolin-3-ol, improves the durability, health and safety profile of the composition. Furthermore, the use of 2-(N-ethylanilino)ethanol and / or 1,2,3,4-tetrahydrobenzo(H)quinolin-3-ol allows the amount of the first curing agent (peroxide) to be reduced without compromising the performance profile of the composition.

[0022] The anaerobic curable composition according to the present invention contains a (meth)acrylate component. Suitable (meth)acrylate components are (meth)acrylate monomers, (meth)acrylate oligomers or (meth)acrylate polymers.

[0023] Suitable (meth)acrylate monomers for use as the (meth)acrylate component in the present invention include H2C=CGCO2R 8 where G can be hydrogen, halogen or an alkyl group having 1 to 4 carbon atoms; R 8 may be selected from alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkaryl, aralkyl or aryl groups having 1 to 16 carbon atoms, which may optionally be substituted or interrupted by silane, silicon, oxygen, halogen, carbonyl, hydroxyl, ester, carboxylic acid, urea, urethane, carbonate, amine, amide, sulfur, sulfonate, sulfone, and the like.

[0024] Additional (meth)acrylate monomers suitable for use herein as the (meth)acrylate component in the present invention or as a component in making the reaction product include multifunctional (meth)acrylate monomers, such as difunctional or trifunctional (meth)acrylates, such as polyethylene glycol di(meth)acrylate, tetrahydrofuran (meth)acrylate and di(meth)acrylate, hydroxypropyl (meth)acrylate ("HPMA"), hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate ("TMPTMA"), diethylene glycol dimethacrylate, triethylene glycol dimethacrylate ("TRIEG MA"), tetraethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, di(pentamethylene glycol) di(meth)acrylate, tetraethylene diglycol di(meth)acrylate, diglycerol tetra(meth)acrylate, tetramethylene di(meth)acrylate, ethylene di(meth)acrylate, neopentyl glycol di(meth)acrylate, bisphenol-A mono- and di(meth)acrylates such as ethoxylated bisphenol-A (meth)acrylate ("EBIPMA"), and bisphenol-F mono- and di(meth)acrylates such as ethoxylated bisphenol-A (meth)acrylate.

[0025] Still other (meth)acrylate monomers that can be used herein include silicone (meth)acrylate moieties ("SiMA"), such as those disclosed in US Pat. No. 5,605,999.

[0026] Other suitable monomers include those of the formula: [ka] The polyacrylate esters include those represented by the formula: Here, R 4is a group selected from hydrogen, halogen, or alkyl of 1 to 4 carbon atoms; q is an integer at least equal to 1, preferably 1 to 4; and X is an organic group containing at least 2 carbon atoms and having a binding capacity of q plus 1. With regard to the upper limit of the number of carbon atoms in X, practical monomers exist for essentially any value. However, as a practical matter, a common upper limit is 50, preferably 30, and most preferably 20 carbon atoms.

[0027] For example, X can be an organic radical of the formula: [ka] Here, each of Y1 and Y2 is an organic group, preferably a hydrocarbon group, containing at least 2 carbon atoms, preferably 2 to 10 carbon atoms, and Z is an organic group, preferably a hydrocarbon group, containing at least 1 carbon atom, preferably 2 to 10 carbon atoms.

[0028] Another class of useful monomers are the reaction products of di- or tri-alkylolamines (eg, ethanolamine or propanolamine) with acrylic acid, as disclosed in French Patent No. 1,581,361.

[0029] Examples of useful acrylate oligomers include those having the general formula: [ka] Here, R 5 represents a group selected from hydrogen, lower alkyl of 1 to 4 carbon atoms, and hydroxyalkyl of 1 to 4 carbon atoms. [ka] Here, R 4 is a group selected from hydrogen, halogen, or lower alkyl having 1 to about 4 carbon atoms; R 6 is a group selected from hydrogen and hydroxyl; [ka] or m is an integer of at least 1, such as 1 to 15 or more, preferably equal to 1 to 8; n is an integer of at least 1, such as 1 to 40 or more, preferably equal to 2 to 10; and p is 0 or 1.

[0030] Representative examples of acrylic ester oligomers corresponding to the above general formula include di-, tri-, and tetraethylene glycol dimethacrylate; di(pentamethylene glycol) dimethacrylate; tetraethylene glycol diacrylate; tetraethylene glycol di(chloroacrylate); diglycerol diacrylate; diglycerol tetramethacrylate; butylene glycol dimethacrylate; neopentyl glycol diacrylate; and trimethylolpropane triacrylate.

[0031] While di- and other polyacrylate esters, especially those mentioned in the previous paragraph, are preferred, monofunctional acrylate esters (esters containing one acrylate group) may also be used. When working with monofunctional acrylate esters, it is highly preferred to use esters with relatively polar alcohol moieties. Such materials are less volatile than low molecular weight alkyl esters, and more importantly, the polar groups tend to provide intermolecular attractions during and after cure, resulting in more desirable cure characteristics as well as a more durable sealant or adhesive. Desirably, the polar groups are selected from labile hydrogen, heterocyclic, hydroxy, amino, cyano, and halo polar groups. Representative examples of compounds in this category include cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, t-butylaminoethyl methacrylate, cyanoethyl acrylate, chloroethyl methacrylate, and the like.

[0032] Another useful class of monomers is prepared by the reaction of monofunctional substituted alkyl or aryl acrylate esters containing active hydrogen atoms on the functional substituent. This monofunctional acrylate terminated material is reacted with an organic polyisocyanate in the appropriate ratio to convert all the isocyanate groups to urethane or ureido groups. The monofunctional alkyl and aryl acrylate esters are preferably acrylates and methacrylates containing hydroxy or amino functional groups in the non-acrylate portion. Acrylic esters suitable for use have the formula: [ka] is shown in where X is -O- or [ka] Selected from, and R 9 is selected from hydrogen or lower alkyl of 1 to 7 carbon atoms; R 7 is selected from hydrogen, chlorine or methyl and ethyl groups; and R 8 is a divalent organic group selected from lower alkylene of 1 to 8 carbon atoms, phenylene, or naphthylene. These groups, when appropriately reacted with polyisocyanates, provide monomers of the general formula: [ka] where n is an integer from 2 to 6; B is a polyvalent organic group selected from substituted and unsubstituted alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, aralkyl, alkaryl, or heterocyclic groups; and R 7 , R 8 and X has the above meaning. Examples of suitable hydroxyl-functional (meth)acrylates include hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate ("HEMA"), hydroxypropyl methacrylate ("HPMA"), hydroxybutyl methacrylate, and mixtures thereof. Other examples of suitable hydroxy-functional (meth)acrylates include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate ("HEMA"), pentaerythritol triacrylate ("PETA"), and 4-hydroxybutyl acrylate.

[0033] The hydroxy-functional (meth)acrylates can have a number average molecular weight of from about 80 to about 1,000 grams / mole, or from about 100 to about 800 grams / mole, or from about 110 to about 600 grams / mole.

[0034] Of course, these (meth)acrylate components may be used in combination. In highly preferred embodiments, the (meth)acrylate component is selected from the group consisting of hydroxyethyl methacrylate, hydroxypropyl methacrylate, poly(ethyl glycol) dimethacrylate, and mixtures thereof.

[0035] Commercially available (meth)acrylate components suitable for use in the present invention include, but are not limited to, hydroxyethyl methacrylate and hydroxypropyl methacrylate from Geo Specialty and Sartomer.

[0036] In the anaerobic curable composition according to the present invention, the (meth)acrylate component can be present in an amount of 87 to 97% by weight, preferably 89 to 97% by weight, more preferably 90 to 96.5% by weight, based on the total weight of the composition.

[0037] The above defined amount ranges are ideal and provide good strength to the anaerobic curable composition according to the invention. Amounts below 87% and above 97% may directly affect the strength of the anaerobic curable composition.

[0038] The anaerobic curable composition according to the present invention contains a first curing agent, which is selected from the group consisting of butyl hydroperoxide, preferably t-butyl hydroperoxide, p-methane hydroperoxide, tert-butyl perbenzoate, diisopropylbenzene hydroperoxide, tert-butylperoxy-3,5,5-trimethylhexanoate, diacetyl peroxide, benzoyl peroxide, tert-butyl peracetate, lauryl peroxide, tert-butyl peroxybenzoate, tert-butylperoxy-2-ethylhexyl carbonate, tert-amyl hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide. and mixtures thereof, more preferably selected from the group consisting of p-methane hydroperoxide, diisopropylbenzene hydroperoxide, tert-butyl peroxy-3,5,5-trimethylhexanoate, tert-butyl peracetate, lauryl peroxide, tert-butyl peroxy-2-ethylhexyl carbonate, tert-amyl hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, and mixtures thereof, and even more preferably the first curing agent is tert-butyl peroxy-3,5,5-trimethylhexanoate.

[0039] In a highly preferred embodiment, the first curing agent is tert-butylperoxy-3,5,5-trimethylhexanoate. Tert-butylperoxy-3,5,5-trimethylhexanoate is particularly preferred due to its improved health and safety profile and the potential for similar curing performance at lower doses.

[0040] Commercially available primary curing agents suitable for use in the present invention include, but are not limited to, p-methane hydroperoxide from MPI Chemie, tert-butyl perbenzoate from Nouryon, benzoyl peroxide from Akzo Nobel, and tert-butylperoxy-3,5,5-trimethylhexanoate from Arkema.

[0041] The anaerobic curable composition according to the present invention may contain 0.1 to 3.0% by weight, preferably 0.15 to 2.5% by weight, more preferably 0.2 to 2.3% by weight of the first curing agent, based on the total weight of the composition.

[0042] The above range is preferred because it provides a good curing profile for the composition according to the present invention. If the amount of the first curing agent is less than 0.1%, the curing rate will be slow and may adversely affect the strength performance of the composition. On the other hand, if the amount is more than 3%, the curing rate will be fast and the composition may become unstable.

[0043] The anaerobic curable composition according to the present invention includes a second curing agent, preferably selected from the group consisting of saccharin, di-p-toluylsulfonimide, tert-butylbenzoyltoluylsulfonamide, methylbenzoyltoluylsulfonamide, methoxybenzoyltoluylsulfonamide, and mixtures thereof, more preferably the second curing agent is saccharin.

[0044] In a highly preferred embodiment, the second curing agent is saccharin. Saccharin is especially preferred because it can also act as a co-accelerator in the composition.

[0045] Commercially available secondary curing agents suitable for use in the present invention include, but are not limited to, saccharin, di-p-toluylsulfonimide, and tert-butylbenzoyltoluylsulfonamide from Univar.

[0046] The anaerobic curable composition according to the present invention may contain 0.1 to 5.0% by weight, preferably 1.0 to 3.5% by weight, more preferably 1.1 to 3.0% by weight of a second curing agent, based on the total weight of the composition.

[0047] The above range is preferred because it provides a good curing profile for the composition according to the present invention. If the amount of the second curing agent is less than 0.1%, the curing speed will be slow, which may adversely affect the strength performance of the composition. On the other hand, if the amount is more than 5%, the curing speed will be fast, which may cause the composition to become unstable.

[0048] In another highly preferred embodiment, the anaerobic curable composition according to the present invention comprises a first curing agent that is tert-butylperoxy-3,5,5-trimethylhexanoate and a second curing agent that is saccharin.

[0049] The composition according to the present invention includes a cure accelerator comprising 2-(N-ethylanilino)ethanol and / or 1,2,3,4-tetrahydrobenzo(H)quinolin-3-ol (TBHQ-ol).

[0050] 2-(N-ethylanilino)ethanol and 1,2,3,4-tetrahydrobenzo(H)quinolin-3-ol (TBHQ-ol) have been selected and are preferred because they offer a better health and safety profile compared to conventional cure accelerators while exhibiting the same or at least comparable reactivity and stability in the compositions according to the invention.

[0051] Commercially available cure accelerators suitable for use in the present invention include, but are not limited to, 2-(N-ethylanilino)ethanol from BASF and 1,2,3,4-tetrahydrobenzo(H)quinolin-3-ol (TBHQ-ol) from Vanamali Organics.

[0052] The anaerobic curable composition according to the present invention may contain 0.1 to 1.5% by weight, preferably 0.2 to 1.0%, and more preferably 0.25 to 0.75% of a curing accelerator based on the total weight of the composition.

[0053] The amount of accelerator is very important to obtain a good curing profile and stability of the composition, and the ranges defined above can provide this: if the amount of accelerator is less than 0.1%, the curing speed may be too slow, and if it is more than 1.5%, it may have a negative effect on the stability of the composition.

[0054] The anaerobic curable composition according to the present invention may further comprise a stabilizer. The stabilizer is preferably selected from the group consisting of benzoquinone, 1,4-naphthoquinone, anthraquinone, hydroquinone, methoxyhydroquinone, tert-butylhydroquinone butylated hydroxytoluene, and mixtures thereof, preferably the stabilizer is 1,4-naphthoquinone.

[0055] The above mentioned stabilizers are preferred because they are proven stabilizers and are capable of preventing premature polymerization of the composition, i.e., providing the necessary shelf-life stability to the composition according to the invention.

[0056] Commercially available stabilizers suitable for use in the present invention include, but are not limited to, 1,4-naphthoquinone from Sigma Aldrich.

[0057] The anaerobic curable composition according to the present invention may contain 0.01 to 1.0% by weight, preferably 0.05 to 0.75% by weight, more preferably 0.1 to 0.4% by weight of a stabilizer, based on the total weight of the composition.

[0058] Amounts of stabilizer less than 0.01% may adversely affect the stability of the compositions according to the present invention, while amounts greater than 1% may not significantly affect the stability and performance of the compositions.

[0059] The anaerobic curable composition according to the present invention may further comprise a chelating agent. Preferably, the chelating agent is selected from the group consisting of ethylenediaminetetraacetic acid sodium salt, N-hydroxyethylenediaminetetraacetic acid trisodium salt (HEDTA Nas), tetrakis-(2-hydroxypropyl)ethylenediamine (EDTPA), diethylenetriaminepentaacetic acid pentasodium salt (DTPA), and mixtures thereof, preferably, the chelating agent is ethylenediaminetetraacetic acid sodium salt.

[0060] The sodium salt of ethylenediaminetetraacetic acid chelating agent is preferred as it is more effective compared to other common chelating agents.

[0061] Commercially available chelating agents suitable for use in the present invention include, but are not limited to, ethylenediaminetetraacetic acid sodium salt from BASF.

[0062] The chelating agent may be present in the anaerobic curable composition according to the present invention in an amount of 0.2 to 2.0% by weight, preferably 0.3 to 1.5% by weight, more preferably 0.6 to 1.2% by weight, based on the total weight of the composition.

[0063] Amounts of chelating agent less than 0.2% may adversely affect the stability of the composition, whereas amounts greater than 2.0% do not significantly affect the stability and performance of the composition.

[0064] The anaerobic curable composition according to the present invention may further comprise a pigment. Preferably, the pigment is selected from the group consisting of 1-phenylazo-2-naphthol (Solvent Yellow 14), 2,4-dihydro-5-methyl-2-phenyl-4-(phenylazo)-3H-pyrazol-3-one (Sudan Yellow 146) and 1,4-bis(p-tolylamino)anthraquinone (Sudan Green 4 B) and mixtures thereof.

[0065] The anaerobic curable composition according to the present invention may contain 0.01 to 0.05% by weight of a pigment, based on the total weight of the composition.

[0066] In a preferred embodiment, the anaerobic curable composition encompassed by the present invention comprises: a) a (meth)acrylate component; b) a primary curing agent, where the primary curing agent is tert-butylperoxy-3,5,5-trimethylhexanoate; c) a secondary curing agent; and d) a cure accelerator comprising 2-(N-ethylanilino)ethanol and / or 1,2,3,4-tetrahydrobenzo(H)quinolin-3-ol.

[0067] In a preferred embodiment, an anaerobic curable composition constructed in accordance with the present invention comprises: a) a (meth)acrylate component; b) a primary curing agent, where the primary curing agent is tert-butylperoxy-3,5,5-trimethylhexanoate; c) a secondary curing agent, where the primary curing agent is saccharin; and d) a cure accelerator comprising 2-(N-ethylanilino)ethanol and / or 1,2,3,4-tetrahydrobenzo(H)quinolin-3-ol.

[0068] In another preferred embodiment, an anaerobic curable composition constructed in accordance with the present invention comprises: a) a (meth)acrylate component; b) 0.1-3.0 wt. %, preferably 0.1-2.75%, more preferably 0.1-2.3% of a first curing agent based on the total weight of the composition, wherein the first curing agent is tert-butylperoxy-3,5,5-trimethylhexanoate; c) a second curing agent; and d) 0.1-1.5 wt. %, preferably 0.2-1.0%, more preferably 0.25-0.75% of 2-(N-ethylanilino)ethanol based on the total weight of the composition and / or 0.1-1.5 wt. %, preferably 0.2-1.0%, more preferably 0.25-0.75% of 1,2,3,4-tetrahydrobenzo(H)quinolin-3-ol based on the total weight of the composition.

[0069] In yet another preferred embodiment, an anaerobic curable composition constructed in accordance with the present invention comprises: a) a (meth)acrylate component; b) 0.1-3.0 wt. %, preferably 0.1-2.75%, more preferably 0.1-2.3% of a first curing agent, based on the total weight of the composition, wherein the first curing agent is tert-butylperoxy-3,5,5-trimethylhexanoate; c) a second curing agent, wherein the second curing agent is saccharin; and d) 0.1-1.5 wt. %, preferably 0.2-1.0%, more preferably 0.25-0.75% of 2-(N-ethylanilino)ethanol, based on the total weight of the composition, and / or 0.1-1.5 wt. %, preferably 0.2-1.0%, more preferably 0.25-0.75% of 1,2,3,4-tetrahydrobenzo(H)quinolin-3-ol, based on the total weight of the composition.

[0070] The present invention also relates to a cured product of the anaerobic curable composition according to the present invention. The present invention relates to the use of the anaerobic curable composition according to the present invention or a cured product thereof in an adhesive, sealant, thread locking agent or retainer. EXAMPLES

[0071] Working Example Example 1 Four anaerobic compositions were prepared with the concentration of 1,2,3,4-tetrahydrobenzo(H)quinolin-3-ol (THBQ-ol) kept at 0.5% w / w and the concentration of tert-butylperoxy-3,5,5-trimethylhexanoate (TBPTH) varied from 0.25 to 1.0% w / w. Details of the preparations are shown in Table 1.

[0072] [Table 1]

[0073] All four preparations were tested for compressive shear strength, break torque and prevail torque on mild steel and stainless steel. The bonded pins and collars, nuts and bolts were cured at room temperature for 1 and 24 hours and the results were recorded and compared to the control preparations. To further understand durability, mild steel pins and collars were bonded and cured at room temperature for 24 hours, then exposed to 100°C for 1000 hours and compared to the strength performance of the control.

[0074] Compressive shear strength on mild steel and stainless steel pin and collar (P&C) was measured according to ASTM D 4562-001.

[0075] Tables 2 and 3 show the compressive shear strength of the four formulations. Table 2 shows the 1-hour room temperature cure compressive shear strength (pin & collar) N / mm 2 The results are shown in Table 3. Compressive shear strength (pin & collar) N / mm after 24-hour room temperature curing 2 The results are illustrated below.

[0076] [Table 2]

[0077] [Table 3]

[0078] From the above test results, it is observed that Examples 2 and 3 exhibit similar 1 hour and 24 hour room temperature cure with similar compressive shear strength against mild steel and stainless steel. The breaking torque of mild steel and stainless steel nuts and bolts (N&B) was measured according to ASTM D 5649-01.

[0079] The breaking torques of all four formulations are shown in Tables 4 and 5. Table 4 shows the 1 hour room temperature curing breaking torque (M10 N&B) in Nm, and Table 5 shows the 24 hour room temperature curing breaking torque (M10 N&B) in Nm.

[0080] [Table 4]

[0081] [Table 5]

[0082] From the above test results, Examples 1-4 all show an improvement in breaking torque in mild steel, but are comparable in stainless steel.

[0083] Prevail torque on mild steel and stainless steel was measured according to ASTM D 5649-01.

[0084] The Prevail Torque for all four formulations is shown in Tables 6 and 7. Table 6 shows the Prevail Torque (N&B) in Nm for 1 hour room temperature cure and Table 7 shows the Prevail Torque (N&B) in Nm for 24 hours room temperature cure.

[0085] [Table 6]

[0086] [Table 7]

[0087] From the above test results, formulation examples 5 and 6 showed an increase in 1-hour room temperature cure prevail torque on mild steel and stainless steel, but when compared to the comparative example, the 24-hour room temperature cure prevail torque on mild steel and stainless steel was similar.

[0088] heat aging All four formulations and a control formulation were used to bond mild steel pins and collars and were cured at room temperature for 24 hours followed by exposure to 1000 hours at 100°C. After 1000 hours at 100°C, the bonded pins and collars were cooled to room temperature and tested for compressive shear strength to determine retention of bond strength. Heat aging tests were performed according to ASTM D 4562-001. Heat aged compressive shear strength N / mm for mild steel (pin & collar) 2 The test results are shown in Table 8.

[0089] [Table 8]

[0090] Heat aging results show that compared to the control, Examples 1 and 2 have comparable retention of compressive shear strength, while Examples 3 and 4 have a 9% loss in compressive shear strength. Overall, all four examples show comparable retention of compressive shear strength as the comparative example.

[0091] Example 2 Four different formulations were prepared while keeping the common ingredients such as methacrylate monomer (PEGDMA), stabilizers, chelating agents, and saccharin at the same concentration. The concentration of EtOH amine was maintained at 0.5% w / w and the concentration of tert-butylperoxy-3,5,5-trimethylhexanoate (TBPTH) was varied to 0.5, 1.0, 1.5, and 2.0% w / w for Examples 5, 6, 7, and 8, respectively, as shown in Table 9. The formulations using the new hardener are compared with Comparative Example 2, which contains the conventional hardeners CHP (1.5%) and DE-pT, DM-oT (0.5%). All the ingredients were mixed for the appropriate time until completely dissolved.

[0092] [Table 9]

[0093] Shear strength performance The above formulations were tested for shear strength, breaking strength and prevail torque against active i.e. mild steel (MS) and inactive stainless steel (SS) substrates after curing at room temperature (25°C) for 1 hour and 24 hours. The pins and collars of the substrates used for shear strength testing were cleaned as per standard practice and five different specimens were bonded with the above formulations as per the standard respectively and tested for shear strength performance after curing at room temperature for 1 hour and 24 hours.

[0094] Shear strength performance was measured according to ASTM D 4562-001. Results after 1 hour cure were recorded for both substrates for Comparative Example 2, Example 5, Example 6, Example 7, and Example 8 and are shown in Table 2.

[0095] Table 10 shows the shear strength performance on mild steel and stainless steel substrates after 1 hour curing.

[0096] [Table 10]

[0097] The results obtained suggest that in all four Examples 5 to 8, the shear strength performance after 1 hour curing is equivalent to that of Comparative Example 2. All examples were tested for shear strength performance after 24 hours cure in a similar manner on both mild steel and stainless steel substrates, and the results are shown in Table 11.

[0098] [Table 11]

[0099] The shear strength performance of all formulations after 24 hours curing on mild steel and stainless steel substrates is comparable to the control product.

[0100] Breakaway Torque Performance Torque performance was measured after 1 hour and 24 hour cure on mild steel and stainless steel substrates at room temperature. The initial torque represents the reduced axial load measurement and is referred to as breakaway torque. Five test specimens of degreased black oxide nuts and bolts were assembled to evaluate the breakaway and pre-bail torque performance of Comparative Example 2 and Examples 5-8, respectively.

[0101] Breakaway torque performance was measured according to ASTM D 5649-01. The breakaway torque measured after one hour cure on mild steel and stainless steel substrates is shown in Table 12.

[0102] [Table 12]

[0103] Breakaway torque results recorded after 1 hour cure for all inventive examples on mild steel and stainless steel substrates were observed to be comparable to Comparative Example 2.

[0104] Table 13 illustrates the breakaway torque performance of mild steel and stainless steel substrates after 24 hour hardening.

[0105] [Table 13]

[0106] Similarly, the breakaway torque strength performance of all formulations is observed to be comparable to Comparative Example 2 on both mild steel and stainless steel substrates.

[0107] Prevail torque performance Prevail torque performance is measured by twisting the nut 360° after the first bond break. oThe prevail torque performance of the formulations is recorded in Tables 14 and 15 below, and it was observed that the examples according to the invention performed nearly similarly to Comparative Example 2 on both mild steel and stainless steel substrates at room temperature after 1 hour and 24 hour cure.

[0108] Prevail torque performance was measured according to ASTM D 5649-01.

[0109] Table 14 shows the prevail torque for mild steel and stainless steel substrates after 1 hour curing, and Table 15 shows the prevail torque for mild steel and stainless steel substrates after 24 hour curing.

[0110] [Table 14]

[0111] [Table 15]

[0112] heat aging performance Heat aged shear strength performance was evaluated after 24 hours of curing and aging at 100° C. for 1000 hours. After heat treatment, the pins and collars were cooled to room temperature and tested for shear strength. The results obtained, as illustrated in Table 16, show that the strength performance of the examples according to the invention is comparable to that of Comparative Example 2.

[0113] Heat aging tests were performed according to ASTM D 4562-001.

[0114] [Table 16]

Claims

1. a) a (meth)acrylate component; b) a first curing agent; c) a second curing agent; and d) a curing accelerator containing 2-(N-ethylanilino)ethanol and / or 1,2,3,4-tetrahydrobenzo(H)quinolin-3-ol 1. An anaerobic curable composition comprising:

2. 2. The anaerobic curable composition of claim 1, wherein the (meth)acrylic monomer is present in an amount of from 87 to 97% by weight, preferably from 89 to 97%, more preferably from 90 to 96.5% by total weight of the composition.

3. The first curing agent is a hydroperoxide, preferably t-butyl hydroperoxide, p-methane hydroperoxide, tert-butyl perbenzoate, diisopropylbenzene hydroperoxide, tert-butylperoxy-3,5,5-trimethylhexanoate, diacetyl peroxide, benzoyl peroxide, tert-butyl peracetate, lauryl peroxide, tert-butyl peroxybenzoate, tert-butylperoxy-2-ethylhexyl carbonate, tert-amyl hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, and mixtures thereof.

2. The anaerobic curable composition of claim 1, wherein the first curing agent is selected from the group consisting of p-methane hydroperoxide, diisopropylbenzene hydroperoxide, tert-butylperoxy-3,5,5-trimethylhexanoate, tert-butyl peracetate, lauryl peroxide, tert-butylperoxy-2-ethylhexyl carbonate, tert-amyl hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, and mixtures thereof, and even more preferably, the first curing agent is tert-butylperoxy-3,5,5-trimethylhexanoate.

4. 2. The anaerobic curable composition of claim 1, wherein the first curing agent is present in an amount of 0.1 to 3.0% by weight of the total weight of the composition, preferably 0.15 to 2.5%, more preferably 0.2 to 2.3%.

5. 2. The anaerobic curable composition of claim 1, wherein the second curing agent is selected from the group consisting of saccharin, di-p-toluylsulfonimide, tert-butylbenzoyltoluylsulfonamide, methylbenzoyltoluylsulfonamide, methoxybenzoyltoluylsulfonamide, and mixtures thereof; preferably, the second curing agent is saccharin.

6. 10. The anaerobic curable composition of claim 1, wherein the secondary curing agent is present in an amount of 0.1 to 5.0 wt. %, preferably 1.0 to 3.5%, more preferably 1.1 to 3.0% of the total weight of the composition.

7. 2. The anaerobic curable composition of claim 1, wherein the cure accelerator is present in an amount of 0.1 to 1.5% by weight of the total weight of the composition, preferably 0.2 to 1.0%, more preferably 0.25 to 0.75%.

8. a) (Meth)acrylate component b) a primary curing agent, where the primary curing agent is tert-butylperoxy-3,5,5-trimethylhexanoate c) a second curing agent; and d) a curing accelerator containing 2-(N-ethylanilino)ethanol and / or 1,2,3,4-tetrahydrobenzo(H)quinolin-3-ol 10. The anaerobic curable composition of claim 1, comprising:

9. tert-butylperoxy-3,5,5-trimethylhexanoate is present in an amount of 0.1 to 3.0% by weight, preferably 0.1 to 2.75%, more preferably 0.1 to 2.3% by weight of the total weight of the composition; and 2-(N-ethylanilino)ethanol is present in an amount of 0.1 to 1.5% by weight, preferably 0.2 to 1.0%, more preferably 0.25 to 0.75% by weight of the total weight of the composition; and / or 1,2,3,4-tetrahydrobenzo(H)quinolin-3-ol is present in an amount of from 0.1 to 1.5% by weight, preferably from 0.2 to 1.0%, more preferably from 0.25 to 0.75% of the total weight of the composition; The anaerobic curable composition of claim 8.

10. 2. The anaerobic curable composition according to claim 1, further comprising a stabilizer, the stabilizer preferably being selected from the group consisting of benzoquinone, 1,4-naphthoquinone, anthraquinone, hydroquinone, methoxyhydroquinone, tert-butylhydroquinone, butylated hydroxytoluene, and mixtures thereof, preferably the stabilizer being 1,4-naphthoquinone.

11. 11. The anaerobic curable composition of claim 10, wherein the stabilizer is present in an amount of 0.01 to 1.0% by weight of the total weight of the composition, preferably 0.05 to 0.75%, more preferably 0.1 to 0.4%.

12. 2. The anaerobic curable composition of claim 1, further comprising a chelating agent, the chelating agent preferably being selected from the group consisting of ethylenediaminetetraacetic acid sodium salt, N-hydroxyethylenediaminetetraacetic acid trisodium salt, tetrakis-(2-hydroxypropyl)ethylenediamine, diethylenetriaminepentaacetic acid pentasodium salt, and mixtures thereof, preferably the chelating agent being ethylenediaminetetraacetic acid sodium salt.

13. 13. The anaerobically curable composition of claim 12, wherein the chelating agent is present in an amount of 0.2 to 2.0% by weight of the total weight of the composition, preferably 0.3 to 1.5%, more preferably 0.6 to 1.2%.

14. A cured product of the anaerobic curable composition according to any one of claims 1 to 13.

15. Use of the anaerobic curable composition according to any one of claims 1 to 13 in adhesives, sealants, thread locks and retainers.

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