Curing of anaerobic compositions

Abstract

To provide a bonding system for bonding a plastic substrate to another substrate, and a bonding method.SOLUTION: There is provided a bonding system for bonding a plastic substrate to another substrate, wherein the bonding system comprises a plastic substrate which is impregnated with a transition metal and an anaerobically curable composition. Cure of the anaerobically curable composition is initiatable by the transition metal when the anaerobically curable composition is contacted with the plastic substrate under anaerobic conditions.SELECTED DRAWING: None

Description

[Technical Field]

[0001] Field of Invention This invention relates to the curing of anaerobic compositions. Anaerobic curable compositions are well known. Typically, anaerobic curable compositions remain uncured when exposed to air (oxygen). Anaerobic curable compositions typically cure under suitable anaerobic conditions.

[0002] In some applications, bonding using anaerobic compositions is cumbersome. For example, some substrates are difficult to bond using anaerobic curing compositions. For such applications, two-component compositions may be formulated. Formulating a composition as a two-component composition provides greater flexibility in component selection. For example, a curing initiator can be placed in one of the two components of the composition. When the two components of the composition are joined under suitable anaerobic conditions, the composition cures.

[0003] Furthermore, primers can be used for substrates that are difficult to bond using anaerobic curing compositions. When joining two substrates, the primer can be applied to at least one of the substrates. Therefore, for example, when joining two substrates, if at least one of the substrates is difficult to bond, the primer can be applied to either substrate, but it is preferable to apply it to the substrate that is difficult to bond. [Background technology]

[0004] Explanation of related technologies Anaerobic adhesives are generally well known. For example, see RDRich, “Anaerobic Adhesives,” in Handbook of Adhesive Technology, 29, 467-79, edited by A. Pizzi and KLMittal, Marcel Dekker, Inc., New York (1994), and the references cited therein. Anaerobic adhesives have many applications, and new applications are constantly being developed.

[0005] Anaerobic adhesive systems are stable in the presence of oxygen but polymerize in the absence of oxygen. Polymerization is often initiated by the presence of free radicals generated from peroxy compounds. Anaerobic adhesive compositions are well known for their ability to remain liquid and non-polymerized in the presence of oxygen, and then harden into a solid state when oxygen is removed.

[0006] In many cases, anaerobic adhesive systems contain resin monomers terminated with polymerizable acrylic acid esters such as methacrylate, ethyl acrylate, and chloroacrylate esters [e.g., polyethylene glycol dimethacrylate and urethane acrylates based on known urethane chemistry (e.g., U.S. Patent No. 3,425,988 (Gorman))]. Other components typically present in anaerobic curing adhesive compositions include initiators such as organic hydroperoxides such as cumene hydroperoxide and tertiary butyl hydroperoxide, accelerators that increase the curing rate of the composition, and stabilizers such as quinones and hydroquinones that are included to help prevent premature polymerization of the adhesive due to the decomposition of peroxy compounds.

[0007] A desirable curing-inducing composition for inducing and promoting anaerobic curing may comprise saccharin, toluidines such as N,N-diethyl-p-toluidine ("DE-pT") and N,N-dimethyl-o-toluidine ("DM-oT"), and one or more of acetylphenylhydrazine ("APH") and maleic acid. See, for example, U.S. Patent No. 3,218,305 (Krieble), No. 4,180,640 (Melody), No. 4,287,330 (Rich), and No. 4,321,349 (Rich).

[0008] Saccharin and APH are used as standard curing accelerator components in anaerobic adhesive curing systems. In fact, many of the LOCTITE® brand anaerobic adhesive products currently available from Henkel Corporation use either saccharin alone or both saccharin and APH.

[0009] Anaerobic curing adhesive compositions also generally include chelating agents, such as ethylenediaminetetraacetic acid (EDTA), which are used to sequestrate metal ions.

[0010] U.S. Patent No. 4,442,138 describes a method for curing an anaerobic resin using a specific transition metal β-ketoester complex applied to the surface of a substrate.

[0011] It is desirable to provide alternative bonding systems and bonding methods that utilize anaerobic curing compositions. [Overview of the project] [Means for solving the problem]

[0012] In one embodiment, the present invention provides a bonding system for joining a plastic substrate to another substrate, the bonding system is Plastic substrates impregnated with transition metals; and, Anaerobic curing composition Includes, The curing of an anaerobic curable composition can be initiated by a transition metal when the anaerobic curable composition comes into contact with a plastic substrate under anaerobic conditions.

[0013] It will be understood that applying liquid materials to a substrate will not impregnate a plastic substrate. When liquid materials are applied to a plastic substrate, a layer is formed on the surface. This surface layer is not considered impregnation. Furthermore, it will be understood that applying liquid materials will not impregnate a plastic substrate, whether or not a vacuum is applied. Plastic substrates are not porous, and the use of vacuum does not affect impregnation.

[0014] Transition metals can exist in the form of salts.

[0015] In the bonding system of the present invention, the transition metal may be any transition metal selected from Groups 3 to 12 of the Periodic Table of the Elements, and combinations thereof. For example, salts of any transition metal selected from Groups 3 to 12 of the Periodic Table of the Elements, and combinations of these salts may be used.

[0016] However, in all cases, it will be understood that the transition metal has redox activity. By being redox active, it becomes possible to participate in the activation of the anaerobic composition (anaerobic curing).

[0017] In the bonding system of the present invention, the plastic substrate can be impregnated with a transition metal when the plastic is in a molten form, for example, during the molding of the plastic substrate.

[0018] The present invention also relates to a method of bonding a plastic substrate to another substrate, the method comprising: providing a plastic substrate impregnated with a transition metal; and, providing an anaerobic curable composition; and, initiating the curing of the anaerobic curable composition by contacting the anaerobic curable composition with the plastic substrate under anaerobic conditions, thereby bringing the transition metal into contact with the anaerobic curable composition and including.

[0019] The transition metal can be titanium, chromium, manganese, iron, cobalt, nickel, copper, zinc, silver, vanadium, molybdenum, ruthenium, and combinations thereof.

[0020] The transition metal may be selected from copper, iron, vanadium, cobalt, chromium, silver, and manganese, and combinations thereof.

[0021] Preferably, the transition metal can be copper, iron, vanadium, cobalt, and chromium, and combinations thereof.

[0022] Preferably, the transition metal is provided in the form of a salt.

[0023] Suitable salts include the following salts and any combination thereof.

[0024] Examples of titanium salts include titanium(IV) bromide; titanium carbonitride powder; Ti2CN; titanium(II) chloride; titanium(III) chloride; titanium(IV) chloride; titanium(III) chloride-aluminum chloride; titanium(III) fluoride; titanium(IV) fluoride; titanium(IV) iodide; and titanium(IV) oxysulfate solution.

[0025] Examples of chromium salts include chromium(II) chloride, chromium(III) bromide, chromium(III) chloride, chromium(III) chloride tetrahydrofuran complex, chromium(III) fluoride, chromium(III) nitrate, chromium(III) perchlorate, chromium(III) phosphate, chromium(III) sulfate, chromyl chloride, CrO2, and potassium chromium(III) oxalate.

[0026] Examples of manganese salts include manganese(II) bromide, manganese(II) carbonate, manganese(II) chloride, manganese(II) cyclohexane butyrate, manganese(II) fluoride, manganese(III) fluoride, manganese(II) formate, manganese(II) iodide, manganese(II) molybdate, manganese(II) nitrate, manganese(II) perchlorate, and manganese(II) sulfate.

[0027] Examples of iron salts include ammonium iron(II) sulfate, iron(II) bromide, iron(III) bromide, iron(II) chloride, iron(III) chloride, iron(III) citrate, iron(II) fluoride, iron(III) fluoride, iron(II) iodide, iron(II) molybdate, iron(III) nitrate, iron(II) oxalate, iron(III) oxalate, iron(II) perchlorate, iron(III) phosphate, iron(III) pyrophosphate, iron(II) sulfate, iron(III) sulfate, iron(II) tetrafluoroborate, and potassium hexacyanoferrate(II).

[0028] Examples of cobalt salts include cobalt(II) naphthenate; cobalt(II) ammonium sulfate; cobalt(II) benzoyl acetonate; cobalt(II) bromide; cobalt(II) carbonate; cobalt(II) chloride; cobalt(II) cyanide; cobalt(II) fluoride; cobalt(III) fluoride; cobalt(II) hydroxide; cobalt(II) iodide; cobalt(II) nitrate; cobalt(II) oxalate; cobalt(II) perchlorate; cobalt(II) phosphate; cobalt(II) sulfate; cobalt(II) tetrafluoroborate; cobalt(II) thiocyanate; cobalt(II) thiocyanate; trans-dichlorobis(ethylenediamine)cobalt(III) chloride; hexaamminecobalt(III) chloride; and pentaamminechlorocobalt(III) chloride.

[0029] Examples of nickel salts include ammonium nickel(II) sulfate; bis(ethylenediamine)nickel(II) chloride; nickel(II) acetate; nickel(II) bromide; nickel(II) bromide ethylene glycol dimethyl ether complex; nickel(II) bromide 2-methoxyethyl ether complex; nickel carbonate; nickel(II) carbonate hydroxide; nickel(II) chloride; nickel(II) cyclohexane butyrate; nickel(II) fluoride; nickel(II) hexafluorosilicate; nickel(II) hydroxide; nickel(II) iodide; nickel(II) nitrate; nickel(II) oxalate; nickel(II) perchlorate; nickel(II) sulfamate; nickel(II) sulfate; potassium nickel(IV) paraperiodate; and potassium tetracyanoniclate(II).

[0030] Examples of copper salts include copper acetate, copper hexanoate, copper 2-ethylhexanoate, copper carbonate; copper(II) acetylacetonate; copper(I) bromide; copper(II) bromide; copper(I) bromide dimethyl sulfide complex; copper(I) chloride; copper(II) chloride; copper(I) cyanide; copper(II) cyclohexane butyrate; copper(II) fluoride; copper(II) formate; copper(II) D-gluconate; copper(II) hydroxide; copper(II) hydroxide phosphate; copper(I) iodide; copper(II) molybdate; copper(II) nitrate; copper(II) perchlorate; copper(II) pyrophosphate; copper(II) selenite; copper(II) sulfate; copper(II) tartrate; copper(II) tetrafluoroborate; copper(I) thiocyanate; and tetraamminecopper(II) sulfate.

[0031] Examples of zinc salts include zinc bromide, zinc chloride, zinc citrate, zinc cyanide, zinc fluoride, zinc hexafluorosilicate, zinc iodide, zinc methacrylate, zinc molybdate, zinc nitrate, zinc oxalate, zinc perchlorate, zinc phosphate, zinc selenite, zinc sulfate, zinc tetrafluoroborate, and zinc p-toluenesulfonate.

[0032] Examples of silver salts include silver bromate; silver carbonate; silver chlorate; silver chloride; silver chromate; silver citrate; silver cyanate; silver cyanide; silver cyclohexane butyrate; silver(I) fluoride; silver(II) fluoride; silver heptafluorobutyrate; silver hexafluoroantimone; silver hexafluoroarsenate(V); silver hexafluorophosphate; silver hydrogen fluoride(I); silver iodide; silver lactate; silver metavanadate; silver molybdate; silver nitrate; silver nitrite; silver pentafluoropropionate; silver perchlorate; silver perrhenate(I); silver phosphate; silver sulfadiazine(I); silver sulfate; silver tetrafluoroborate; silver thiocyanate; and p-toluenesulfonate.

[0033] Examples of vanadium salts include vanadium(III) acetylacetonate; vanadium(II) chloride; vanadium(III) chloride; vanadium(IV) chloride; vanadium(III) chloride tetrahydrofuran complex; vanadium(V) oxychloride; and vanadium(V) oxyfluoride.

[0034] Examples of molybdenum salts include molybdenum(III) chloride, molybdenum(V) chloride, and molybdenum(VI) dichloride dioxide.

[0035] Examples of ruthenium salts include chloropentaammineruthenium(II) chloride; hexaammineruthenium(II) chloride; hexaammineruthenium(III) chloride; pentaamminechlororuthenium(III) chloride; ruthenium(III) chloride; ruthenium iodide; nitrosylruthenium(III) chloride; and ruthenium(III) nitrosylnitrate.

[0036] The transition metal salts can be selected from cobalt(II) naphthenate; copper carbonate; copper(II) acetylacetonate; silver nitrate; vanadium(III) acetylacetonate; and combinations thereof.

[0037] It will be understood that a very wide range of plastics can be joined using the present invention. In fact, joining can be achieved with plastics other than polyolefins. Plastics that can be joined using the present invention include PCABS (polycarbonate / acrylonitrile butadiene styrene); polycarbonate; polyarylamide; Examples include polyamides and acrylic plastics, the plastic being optionally transparent such that the substrate is transparent, for example the plastic being used as a glass substitute (such as one based on acrylic plastic and known as Perspex®), and / or the plastic being optionally reinforced with fibers such as glass fibers.

[0038] The present invention is particularly useful when both substrates are plastic. For example, the results below show a dramatic improvement in bonding strength, including tensile strength, including tensile shear strength, when both substrates are plastic, by utilizing the system of the present invention when little or no bonding / curing is expected to occur.

[0039] It will be understood that the compositions of the present invention can be used in the assembly of devices that include plastic parts to be joined during assembly. In such cases, at least one of the plastic parts is impregnated with a transition metal. For example, this system of the present invention can be used in electronic devices such as portable electronic devices.

[0040] It will be understood that the present invention is particularly useful for one-component anaerobic curable compositions. Therefore, good bonding can be achieved using a one-component composition.

[0041] Furthermore, it will be understood that the present invention does not require the use of a primer. The present invention can be used without a primer.

[0042] In particular, the present invention can achieve bonding between two plastic substrates, at least one, preferably both, of which are impregnated with a transition metal. This can be done using a one-component composition, and it can be done without the use of a primer.

[0043] The anaerobic curing composition includes an anaerobic curing component that undergoes anaerobic curing and a curing component that cures the anaerobic curing component.

[0044] The anaerobic curing component is typically present in an amount of about 50% to 99% by weight of the total composition, for example, about 55% to 95% by weight.

[0045] The curing component in the anaerobic curable composition may be present in an amount of about 0.1 to about 10% by weight, for example, about 1 to about 5% by weight, based on the total weight of the composition.

[0046] Preferably, the anaerobic curing component includes a rubber component such as a natural or synthetic rubber / elastomer component. This component may be present in an amount of about 5 to about 35% by weight, for example, about 10 to about 35% by weight, or for example, about 15 to about 30% by weight, based on the total weight of the composition.

[0047] Transition metals (in whatever form they are used in, e.g., salt form) may be present in amounts up to about 1% by weight of the composition forming the plastic component. Even with such relatively low filler amounts, activation of the anaerobic composition for curing can occur. For example, transition metals may be present in amounts from about 0.01% to about 1% by weight of the composition forming the plastic component.

[0048] The anaerobic curing composition may have an anaerobic curing component based on a suitable (meth)acrylate component.

[0049] One or more preferred (meth)acrylate components may be selected from among (meth)acrylates having the following formulas: H2C=CGCO2R 8 (wherein G may be hydrogen, a halogen, or an alkyl group having 1 to about 4 carbon atoms, R 8 The group may be selected from alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkaryl, aralkyl, or aryl groups having 1 to about 16 carbon atoms, any of which may be optionally substituted or interposed with silane, silicon, oxygen, halogen, carbonyl, hydroxyl, ester, carboxylic acid, urea, urethane, polyurethane, carbonate, amine, amide, sulfur, sulfonate, and sulfone.

[0050] One or more preferred (meth)acrylates are, for example, but are not limited to, polyfunctional (meth)acrylates, difunctional (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 ("TRIEGMA"), tetraethylene diglycol dimethacrylate The following can be selected from rilate, dipropylene glycol dimethacrylate, di(pentamethylene glycol) dimethacrylate, tetraethylene diglycol diacrylate, diglycerol tetramethacrylate, tetramethylene dimethacrylate, ethylene dimethacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, and 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-F (meth)acrylate.

[0051] For example, an anaerobic curing component is bisphenol A dimethacrylate:

[0052] [ka] It may include.

[0053] Further (meth)acrylates that may be suitable for use herein are silicone (meth)acrylate substructures ("SiMA"), for example, taught and claimed in U.S. Patent No. 5,605,999 (Chu), the disclosure of which is expressly incorporated herein by reference.

[0054] Other suitable materials may be selected from polyacrylate esters represented by the following formula:

[0055] [ka] (In the formula, R 4 is a group selected from hydrogen, halogens, or alkyl groups with 1 to about 4 carbon atoms; q is an integer equal to at least 1, preferably 1 to about 4; and X is an organic group containing at least 2 carbon atoms with a total bonding strength of q+1. Regarding the upper limit on the number of carbon atoms in X, there are monomers that are effective at essentially any value. However, as a matter of practicality, the general upper limit is about 50 carbon atoms, for example, preferably about 30, and preferably about 20.

[0056] For example, X could be an organic group in the following formula:

[0057] [ka] (In the formula, Y 1 and Y 2 Each of these is an organic group containing at least two carbon atoms, preferably two to about ten carbon atoms, such as a hydrocarbon group, and Z is an organic group containing at least one carbon atom, preferably two to about ten carbon atoms, preferably a hydrocarbon group. Other materials may be selected from reaction products of di- or tri-alkylolamines (e.g., ethanolamine or propanolamine) with acrylic acid, as disclosed in French Patent No. 1,581,361.

[0058] Alternatively, suitable oligomers having (meth)acrylate functional groups may be used. Examples of such (meth)acrylate-functionalized oligomers include those having the following general formula:

[0059] [ka] [In the formula, R5 This includes hydrogen, alkyl groups with 1 to about 4 carbon atoms, hydroxyalkyl groups with 1 to about 4 carbon atoms, or

[0060] [ka] (In the formula, R 4 R is a group selected from hydrogen, halogens, or alkyl groups with 1 to about 4 carbon atoms. 6 is hydrogen, hydroxyl, or

[0061] [ka] A base selected from the following, where m is an integer at least equal to 1, e.g., 1 to about 15 or greater, preferably 1 to about 8; n is an integer at least equal to 1, e.g., 1 to about 40 or greater, preferably about 2 to about 10; and p is 0 or 1.

[0062] Typical examples of acrylic acid 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.

[0063] Di- and other polyacrylate esters, particularly those described in the preceding section, may be preferred, but monofunctional acrylate esters (esters containing one acrylate group) may also be used.

[0064] Suitable compounds can be selected from cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, t-butylaminoethyl methacrylate, cyanoethyl acrylate, and chloroethyl methacrylate.

[0065] Another useful type of material is the reaction product of a (meth)acrylate-functionalized, hydroxyl- or amino-containing material and a polyisocyanate in a suitable ratio to convert all isocyanate groups to urethane or ureido groups, respectively.

[0066] The (meth)acrylate urethane or urea ester thus formed may contain a hydroxy or amino functional group in its non-acrylate portion. Suitable (meth)acrylate esters for use can be selected from those of the following formula:

[0067]

Chemical formula

[0068]

Chemical formula

[0069] These groups, by appropriate reaction with a polyisocyanate, produce monomers of the following general formula:

[0070]

Chemical formula

[0071] (wherein n is an integer between 2 and about 6; B is a polyvalent organic group (both substituted and unsubstituted) selected from alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, alkaryl, alkaryl, and heterocyclic groups, as well as combinations thereof; R 7 , R 8 , and X have the meanings shown above.

[0072] Depending on the properties of B, these (meth)acrylate esters having urea or urethane bonds may have molecular weights that classify them into the oligomer class (e.g., from about 1,000 g / mol to about 5,000 g / mol) or the polymer class (e.g., greater than about 5,000 g / mol).

[0073] Other unsaturated reactive monomers and oligomers, such as styrene, maleimide, vinyl ethers, allyl, allyl ethers, and those described in U.S. Patent No. 6,844,080, B1 (Kneafsey et al.), can be used. Vinyl resins, such as those described in U.S. Patent No. 6,433,091 (Xia), can also be used. Methacrylate or acrylate monomers containing these unsaturated reactive groups can also be used.

[0074] Naturally, these (meth)acrylates can also be used in combination with other monomers.

[0075] Preferably, the anaerobic curing component contains at least one acrylate or methacrylate ester group.

[0076] Preferably, the anaerobic curing component includes at least one selected from the following: epoxy (meth)acrylate, urethane (meth)acrylate, urethane di(meth)acrylate, alkyl (meth)acrylate, stearyl (meth)acrylate, isocyanurate (meth)acrylate, bisphenol-A-(meth)acrylate, ethoxylated bisphenol-A-(meth)acrylate, bisphenol-F-(meth)acrylate, ethoxylated bisphenol-F-(meth)acrylate, bisphenol-A-di(meth)acrylate, ethoxylated bisphenol-A-di(meth)acrylate, bisphenol-F-di(meth)acrylate, and ethoxylated bisphenol-F-di(meth)acrylate.

[0077] The anaerobic composition may also contain other conventional components, such as free radical initiators, free radical promoters, free radical generation inhibitors, and metal catalysts such as iron and copper.

[0078] Many well-known free radical polymerization initiators may be incorporated into the present invention, but are not limited to, hydroperoxides such as CHP, paramentane hydroperoxide, t-butyl hydroperoxide ("TBH"), and t-butyl perbenzoate. Other peroxides include benzoyl peroxide, dibenzoyl peroxide, 1,3-bis(t-butylperoxyisopropyl)benzene, diacetyl peroxide, diacetyl peroxide, butyl 4,4-bis(t-butylperoxy)valerate, p-chlorobenzoyl peroxide, cumene hydroperoxide, t-butylcumyl peroxide, t-butyl perbenzoate, di-t-butyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di-t-butylperoxyhexane, 2,5-dimethyl-2,5-di-t-butylperoxyhexa-3-yne, 4-methyl-2,2-di-t-butylperoxypentane, and combinations thereof.

[0079] Such peroxide compounds are typically used in the present invention in an amount ranging from about 0.1% to about 10% by weight, based on the total weight of the composition, and preferably in an amount of about 1% to about 5% by weight.

[0080] If desired, the initiator component may be encapsulated. For example, the initiator component may be an encapsulated peroxide, such as encapsulated benzoyl peroxide.

[0081] The composition used in the present invention may further contain a thickener and / or a filler.

[0082] As described above, it will be understood that the compositions used in the present invention may include non-reactive species, including resins. Such components do not participate in the anaerobic curing reaction. They are non-reactive. However, such components may be incorporated into the curing of other components during curing and become part of the cured product. Examples of such non-reactive species include fumed silica, polyethylene, PTFE, mica, polyamide wax, titanium dioxide, and barium sulfate.

[0083] The present invention also provides a bonding method using an anaerobic adhesive composition, and a reaction product of the composition.

[0084] The anaerobic curing compositions for use in the present invention may be prepared using conventional methods well known to those skilled in the art. For example, the components of the composition can be mixed in any convenient order in accordance with the roles and functions that each component is intended to perform in the composition. Conventional mixing techniques using known apparatus may also be used.

[0085] Embodiments of the present invention will be described simply as examples with reference to the following accompanying drawings. [Brief explanation of the drawing]

[0086] [Figure 1]The diagram shows an exploded view of various component layers of a portable consumer electronic display device, where the bonding system of the present invention may be used to join a plastic component to one or more other components. [Modes for carrying out the invention]

[0087] Detailed explanation Examples of one or more articles that can be formed using the bonding system of the present invention can be understood by referring to Figure 1. Here, several articles used in the assembly of portable consumer electronic devices will be considered as benefiting from the bonding system of the present invention. Articles that can be bonded using the bonding system of the present invention include: 1. touch panel window 11 and cover 12; 2. speaker 21 and camera lens 22; 3. cover 31, metal trim 32, and subframe 33; and 4. touch panel 41, plastic bezel 42, and metal trim 43. According to the present invention, at least one plastic part to be bonded to the other part is impregnated with a transition metal, and an anaerobic curable composition activated by the transition metal is used to bond the part. In all embodiments of the present invention, it will be understood that suitable anaerobic conditions can be achieved, for example, when the anaerobic composition is sufficiently isolated from the ambient air (oxygen) by joining the parts to be bonded together, such that the parts to be bonded together create anaerobic conditions. [Examples]

[0088] experiment To demonstrate the present invention, the following experimental procedures were performed. It is shown that impregnation of a plastic substrate with a transition metal facilitates bonding using anaerobic adhesives.

[0089] The following anaerobic adhesives were prepared (all quantities within ±10%).

[0090] [Table 1]

[0091] As a control standard, commercially available PCABS lapshear was bonded using the anaerobic adhesive shown in Table 1 above under anaerobic conditions and the following curing conditions (20 minutes at 80°C, followed by 24 hours at room temperature). The achieved bond strength was low, and the bond was easily separated by hand.

[0092] In the following tests, all bonding was performed using the compositions listed in Table 1 above.

[0093] Pin to Wrapshare Test 700 ppm of 97% copper(II) acetylacetonate powder was added to PCABS pellets. The pellets were then molded into pins for bonding with the adhesive shown in Table 1. The plastic underwent slight discoloration during molding.

[0094] The pins were bonded to the lap shear at 80°C for 20 minutes, followed by 24 hours at room temperature, in accordance with the standard test method DIN EN 15870, as shown in Table 2 below, and then the tensile strength was tested (thus, the two substrates (pin and lap shear) were bonded for the tensile bond strength test).

[0095] [Table 2]

[0096] Wrap shear for tensile shear testing 700 ppm of 97% copper(II) acetylacetonate powder was added to PCABS pellets. The pellets were then molded into wrap shears for bonding using the adhesives shown in Table 3. The plastic underwent slight discoloration during molding.

[0097] The lap shears were bonded to the lap shears shown in Table 3 below, in accordance with the standard test method ISO 4587, at 80°C for 20 minutes, followed by 24 hours at room temperature, and then the tensile shear strength was tested (therefore, two substrates (the first lap shear and the second lap shear) were bonded for the tensile shear strength test).

[0098] [Table 3]

[0099] All wraps were molded in-house unless otherwise stated as standard.

[0100] "SF" indicates substrate failure, meaning the substrate broke before reaching the joint shear strength.

[0101] The results above demonstrate that incorporating transition metal components into a plastic substrate, for example during its molding, results in much better bonding by anaerobic curing adhesives.

[0102] As used herein in connection with the present invention, the terms “comprises / comprising” and “having / including” are used to identify the presence of a described feature, integer, process, or component, but do not exclude the presence or addition of one or more other features, integers, processes, components, or groups thereof.

[0103] For clarity, it should be understood that certain features of the invention described in the context of separate embodiments may be provided in combination in a single embodiment. Conversely, for brevity, various features of the invention described in the context of a single embodiment may be provided separately or in any preferred subcombination.

Claims

1. A bonding system for joining a plastic substrate to another substrate without using a primer, (a) Plastic substrates containing a transition metal, wherein the transition metal is in salt form and is selected from the group consisting of cobalt(II) naphthenate, copper carbonate, copper(II) acetylacetonate, silver nitrate, vanadium(III) acetylacetonate, and combinations thereof; and (b) Anaerobic curing compositions; Includes, The aforementioned anaerobic curing composition, The following formula: H ２ C=CGCO ２ R ８ (wherein G is hydrogen, halogen, or alkyl group having 1 to 4 carbon atoms, R ８ (These are selected from alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl, alkaryl, aralkyl, or aryl groups having 1 to 16 carbon atoms, and any of these may be optionally substituted or interposed with silane, silicon, oxygen, halogen, carbonyl, hydroxyl, ester, carboxylic acid, urea, urethane, polyurethane, carbonate, amine, amide, sulfur, sulfonate, and sulfone.) One or more (meth)acrylate components having, A rubber / elastomer component in an amount of 15% to 30% by weight based on the total weight of the anaerobic curing composition, and Peroxides as free radical initiators, Includes, The aforementioned plastic substrate is a mixture of the plastic and a transition metal while the plastic is in a molten state. The transition metal is present in an amount of up to 1% by weight based on the total weight of the composition forming the plastic substrate. The aforementioned plastic substrate is PCABS (polycarbonate / acrylonitrile butadiene styrene), polycarbonate, polyarylamide, or polyamide. The curing of an anaerobic curable composition is a bonding system in which curing can be initiated by a transition metal when the anaerobic curable composition comes into contact with a plastic substrate under anaerobic conditions.

2. The bonding system according to claim 1, wherein the other substrate is a plastic substrate.

3. The bonding system according to claim 1 or 2, wherein the plastic substrate is transparent and / or reinforced with fibers.

4. The bonding system according to claim 1 or 2, wherein the anaerobic curable composition comprises an anaerobic curable component that undergoes anaerobic curing and a curing component that cures the anaerobic curable component, and the anaerobic curable component is present in an amount of 50 to 99% by weight based on the total weight of the anaerobic curable composition.

5. The bonding system according to claim 1 or 2, wherein the peroxide is present in an amount of 0.1 to 10% by weight based on the total weight of the anaerobic curable composition.

6. The bonding system according to claim 1 or 2, wherein the anaerobic curable composition is a one-component composition.

7. A joining system according to claim 1 or 2, used for assembling a device that includes plastic parts to be joined during assembly.

8. A method for joining a plastic substrate to another substrate without using a primer, (a) To provide a plastic substrate impregnated with a transition metal, wherein the transition metal is in salt form and is selected from the group consisting of cobalt(II) naphthenate, copper carbonate, copper(II) acetylacetonate, silver nitrate, vanadium(III) acetylacetonate, and combinations thereof; (b) To provide an anaerobic curing composition; Here, the anaerobic curing composition is The following formula: H ２ C=CGCO ２ R ８ (wherein G is hydrogen, halogen, or alkyl group having 1 to 4 carbon atoms, R ８ (These are selected from alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl, alkaryl, aralkyl, or aryl groups having 1 to 16 carbon atoms, and any of these may be optionally substituted or interposed with silane, silicon, oxygen, halogen, carbonyl, hydroxyl, ester, carboxylic acid, urea, urethane, polyurethane, carbonate, amine, amide, sulfur, sulfonate, and sulfone.) One or more (meth)acrylate components having, A rubber / elastomer component in an amount of 15% to 30% by weight based on the total weight of the anaerobic curing composition, and Peroxides as free radical initiators, Includes, (c) Initiating the curing of the anaerobic curable composition by bringing the anaerobic curable composition into contact with a plastic substrate under anaerobic conditions and bringing a transition metal into contact with the anaerobic curable composition; Includes, The aforementioned plastic substrate is a mixture of the plastic and a transition metal while the plastic is in a molten state. The transition metal is present in an amount of up to 1% by weight based on the total weight of the composition forming the plastic substrate. The method wherein the plastic substrate is PCABS (polycarbonate / acrylonitrile butadiene styrene), polycarbonate, polyarylamide, or polyamide.

9. A method for joining plastic substrates to another substrate, comprising joining substrates to each other using the joining system described in claim 1.

10. The method for joining a plastic substrate to another substrate according to claim 8 or 9, wherein the other substrate is a plastic substrate.

11. A method for joining a plastic substrate to another substrate according to claim 8 or 9, used for assembling a device which includes plastic components to be joined during assembly.

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