WO2025186335A1

WO2025186335A1 - A dual curable composition

Info

Publication number: WO2025186335A1
Application number: PCT/EP2025/056024
Authority: WO
Inventors: Sonia BICCAI; Michael Doherty; Barry Burns
Original assignee: Henkel AG and Co KGaA
Current assignee: Henkel AG and Co KGaA
Priority date: 2024-03-05
Filing date: 2025-03-05
Publication date: 2025-09-12
Anticipated expiration: 2026-09-05
Also published as: WO2025186335A8; GB202403209D0; GB2638999A

Abstract

A dual curable composition A solid curable composition that is both UV curable and anaerobically curable, the solid curable composition comprising: (i) an anaerobically curable component; (ii) a curing component for curing the anaerobically curable component; (iii) a film forming polymer component that is activatable by UV radiation; and (iv) a photoinitiator component.

Description

Title

A dual curable composition

Field

[0001] The present invention relates to a curable composition that is both UV-curable and anaerobically curable.

Related Art

[0002] Anaerobically curable compositions generally are well known. See e.g. R.D. Rich, "Anaerobic Adhesives" in Handbook of Adhesive Technology, 29, 467- 79, A. Pizzi and K.L. Mittal, eds., Marcel Dekker, Inc., New York (1994), and references cited therein. Their uses are legion and new applications continue to be developed.

[0003] Anaerobic adhesive systems are those which are stable in the presence of oxygen, but which polymerize in the absence of oxygen. Polymerization is initiated by the presence of free radicals, often generated from peroxy compounds. Anaerobic adhesive compositions are well known for their ability to remain in a liquid, unpolymerized state in the presence of oxygen and to cure to a solid state upon the exclusion of oxygen.

[0004] Oftentimes anaerobic adhesive systems comprise resin monomers terminated with polymerizable acrylate ester such as methacrylate, ethylacrylate and chloroacrylate esters [e.g., polyethylene glycol dimethacrylate and urethaneacrylates (e.g., U.S. Patent No. 3,425,988 (Gorman)] derived according to known urethane chemistry. Other ingredients typically present in anaerobically curable adhesive compositions include initiators, such as an organic hydroperoxide for example cumene hydroperoxide, tertiary butyl hydroperoxide and the like, accelerators to increase the rate at which the composition cures, and stabilizers such as quinone or hydroquinone, which are included to help prevent premature polymerization of the adhesive due to decomposition of peroxy compounds.

[0005] Desirable cure-inducing compositions to induce and accelerate anaerobic cure may include one or more of saccharin, toluidines, such as N,N- diethyl-p-toluidine ("DE-p-T") and N,N-dimethyl-o-toluidine ("DM-o-T"), and acetyl phenyl hydrazine ("APH") with maleic acid. See e.g. U.S. Patent Nos. 3,218,305 (Krieble), 4,180,640 (Melody), 4,287,330 (Rich) and 4,321 ,349 (Rich).

[0006] Saccharin and APH are used as standard cure accelerator components in anaerobic adhesive cure systems. Indeed, many of the LOCTITE®-brand anaerobic adhesive products currently available from Henkel Corporation use either saccharin alone or both saccharin and APH.

[0007] Anaerobically curable adhesive compositions also commonly include chelators such as ethylenediamine tetra-acetic acid (EDTA) which are employed to sequester metal ions.

[0008] Compositions that are suitable for use in pre-applied threadlocking applications are typically applied in a dry to touch form but with later stage anaerobic cure functionality.

[0009] In some cases the dry to touch form is achieved using a cure mechanism. For example a first cure mechanism may form the dry to touch form so as to hold the composition in place on an article while a second cure mechanism is activated later to achieve threadlocking.

[0010] For example European Patent No. 0 077 659 (Thompson) describes a pre-applied polymerizable fluid for sealing and locking engineering parts. The composition has two mechanisms for curing and two curing reactions take place. The first mechanism is a UV light cure. An opacifier is dispersed in the fluid so that the fluid becomes substantially opaque to radiation. After the fluid is applied to the component it is exposed to UV radiation whereupon a coating is formed, creating a surface layer which is a dry, tack-free crust. The subcutaneous fluid is unaffected by the radiation and remains in a generally liquid state. When the component is threaded into another the surface layer breaks and the second polymerisation (such as a free radical polymerization) is initiated and the second cure reaction takes place once an anaerobic environment is established as the threaded components interlock. The second polymerization mechanism acts to lock the threads together. In Thompson, only a skin is formed in the first polymerization and the remainder of the composition remains fluid below the skin. There is a risk therefore that during handling of the coated engineering parts the skin may be disrupted and the fluid composition may leak out. [0011] Similarly, European Patent No. 0 548 369 (llsami) describes a preapplied adhesive composition for application to the threaded contact faces of a screw member such as a screw. The composition comprises a photo-hardening binder in which a secondary curable composition is dispersed. The secondary curable composition includes microencapsulated reactive monomer/activator/initiator.

[0012] International Patent Publication W02004/024841 A2 (Haller) describes curable compositions for application to a threaded article. The composition comprises a dispersion of components of a first cure mechanism comprising: (a) a (meth)acrylate functional monomer component; (b) a (meth)acrylate functional oligomer component; and (c) a photoinitiator component; and (ii) components of a second cure mechanism comprising: (e) an amine component; and (f) an encapsulated epoxy resin component; together with (iii) a thickener component. The photoinitiator component is suitable upon irradiation of the composition to achieve a first cure through the depth of the composition applied to a threaded article so that a binder matrix is formed with the components of the second cure mechanism dispersed through the matrix.

[0013] U.S. Patent No. 9,181 ,457 (Attarwala) describes dry-to-the-touch compositions containing a polymeric matrix and an anaerobically curable component present within the polymeric matrix. In a particularly desirable form, the compositions are moisture curable. The compositions are non-flowable at high temperatures, and have an improved solvent resistance once cured. The compositions are useful as threadlocking compositions, and can be formulated as coatings on a carrier substrate, such as a tape, a string or a sheet.

[0014] British Patent No. 2,543,756 (Ledwith) describes a threadlocking composition comprising an anaerobically curable component and a curing component for curing the anaerobically curable component; wherein the composition is in flowable particulate form and has a melting point in the range 30-100 °C. The anaerobically curable component may comprise an anaerobically curable monomer and a resin component. The composition may be provided in at least two-part form. The anaerobically curable component is preferably provided in powder form. Preferably the resin component is selected from methacrylated polyurethane resins, novolac resins or higher methacrylated polyester resins. The anaerobically curable monomer preferably comprises at least one acrylate or methacrylate ester group. The composition is preferably solvent-free. Also disclosed is a method of threadlocking two threaded articles together comprising applying said composition to the threads of at least one article so as to fuse it by melting to the threads; subsequently, and optionally after cooling, threading the two articles together so as to initiate anaerobic cure of the threadlocking composition so as to chemically bond the two articles together. An article having said composition applied thereto is also disclosed.

[0015] US Patent Publication No. 4,039,705 (Douek) is concerned with anaerobically curable pressure sensitive adhesive stocks such as sheets and tapes from which a pressure sensitive adhesive layer including at least one anaerobic resin system which can be completely transferred to one substrate to be bonded to another, and cured upon activation by a peroxy initiator and the exclusion of oxygen. The anaerobic pressure sensitive adhesive is contained between two different release surfaces, which enables transfer of the pressure adhesive to a substrate which is to be firmly secured to another upon cure of the anaerobically curable pressure sensitive adhesive.

[0016] US Patent Publication No. 2021/0403758 (Fearon) describes a UV anaerobically curable liquid adhesive. Here the UV cure is used, in a separate step, to cure the adhesive fillet caused by squeeze out of the adhesive from the bond line as the two substrate surfaces are mated together. The UV cure is used because the adhesive fillet that is squeezed out from the bond line is no longer subject to the anaerobic conditions which prevails between the mating surfaces of the substrates. So the UV cure is used to cure composition that is not subject to anaerobic conditions.

[0017] Notwithstanding the compositions that are described above, there is still a necessity to provide curable compositions that have advantageous properties.

[0018] Further, for some applications, bonding with an anaerobically curable composition is troublesome. For example, some substrates are difficult to bond with anaerobically curable compositions. While anaerobically curable compositions display good performance on metal substrates, such compositions typically do not display good performance on glass or plastic substrates. Thus, there is a specific need to tailor anaerobically curable compositions to perform well on such substrates. It is possible to use a primer for substrates that are difficult to bond such as plastic and glass when utilising anaerobically curable compositions. Where two substrates are to be bonded together, primer may be applied to at least one of the substrates. For example, plastic adhesion with one- component anaerobically curable adhesives can be achieved with solvent-based activators typically containing metal catalysts and optionally amine accelerators. The process may be undesirable for end users as it adds an extra application step and requires the solvent to dry.

Summary

[0019] The present invention provides a solid curable composition that is both UV curable and anaerobically curable, the solid curable composition comprising:

(i) an anaerobically curable component;

(ii) a curing component for curing the anaerobically curable component;

(iii) a film forming polymer component that is activatable by UV radiation; and

(iv) a photoinitiator component.

[0020] Compositions of the invention can be useful as threadlockers, for gasketing, for adhesion to oily substrates, as sealants such as pipe sealants, and for joint repair.

[0021] The film forming polymer component is activatable by UV radiation in the presence of the photoinitiator component. The solid curable composition of the invention is in solid form as the film forming polymer component imparts the solid form. The film forming polymer component may also be referred to as a film former or a film forming component.

[0022] The composition of the invention will typically include a cure system for anaerobic cure typically a redox cure system.

[0023] The solid curable composition of the invention is a one-part composition.

[0024] The film forming polymer component acts as a polymeric binder within a solid curable composition of the invention. In this way it may impart a solid form to the solid curable composition of the invention.

[0025] The UV curable nature of the composition is imparted by the film forming polymer component and a photoinitiator component. The film forming polymer component functions as a cross-linker during cure, such as during UV cure, of the solid curable composition. This cross-linking occurs in the presence of the photoinitiator component.

[0026] In the present invention the film forming polymer component is also reactive during cure of the curable composition. For example it desirably cross-links, and typically this is with the anaerobically curable component.

[0027] The film forming polymer component is reactive to free radical reaction mechanisms. For example it desirably participates in free radical crosslinking processes.

[0028] Cross-linking in this way means that:

(i) under conditions where (only) anaerobically induced cure occurs (redox induced free radical cure), the film forming polymer component cross-links with the curing anaerobically curable component;

(ii) under conditions where (only) non-anaerobic cure occurs, for example under conditions where UV induced cure occurs (UV induced decomposition of the photoinitiator component to form free radicals), the curing film forming polymer component cross-links with the anaerobically curable component; and

(iii) under conditions where both anaerobically induced cure and non- anaerobically induced cure occurs, the curing film forming polymer component cross-links with the (anaerobically) curing anaerobically curable component.

[0029] The present invention thus provides a composition that will cure under redox induced free radical cure and UV induced free radical cure. In a composition of the invention the cure mechanism is the same for both anaerobically and UV induced polymerisation that is both occur by free radical crosslinking. It is the trigger for/inducement of this free radical crosslinking that differs between the two modes of cure.

[0030] A solid curable composition of the invention will be in the form of a solid for example in the form of a film. The film forming polymer component imparts the solid form to the solid curable composition of the invention.

[0031] High amounts of anaerobically curable component relative to the film forming polymer component are desirable and thus the use of a solid anaerobically curable component is also desired.

[0032] The solid curable compositions of the invention may be substantially solid and may be provided in any suitable solid form. Such suitable solid forms including tape form, filament form, stick form, or as a coating applied to a substrate including for example a filament or thread made from another material such as a nylon or polyester thread.

[0033] The solid curable compositions of the invention may be formed with a thickness of from about 10 to about 1,000 pm, from example from about 50 to about 250 pm. [0034] The solid curable compositions of the invention may be used in any suitable application. For example they may be provided on threaded articles in solid form, provided in a thread form or provided in a tape form. The compositions of the invention may be provided on a carrier or may be in a self-supporting form.

[0035] The present invention also relates to a method of preparing a threaded part and a method of assembling threaded parts. The solid curable compositions can be easily handled and applied to threaded members. The solid curable compositions may be thermally resistant at temperatures of at least 100 °C for example at temperatures up to 150 °C, such as up to 180 °C, for example up to 200 °C.

[0036] Solid curable compositions of the invention, which may be in the form of a film accomplish one or more of the advantages described herein.

[0037] Solid curable compositions of the invention contain, a polymeric binder formed from a film forming polymer component, an anaerobically curable component, anaerobic cure system. The solid curable composition of the invention includes a photoinitiator component that can be activated by UV. The anaerobic cure system/ photoinitiator component do not dissociate to an appreciable amount by exposure to heat.

[0038] Solid curable compositions of the invention, which may be in the form of a film, are solid at ambient temperatures and the reactive groups of the curable resins have limited mobility in the solid state. It will be appreciated that references to solid film adhesive refers to the state of the film adhesive at ambient conditions, as the adhesive can be softened at elevated temperatures to accomplish the processing steps described herein, although it returns to its solid state upon a return to ambient conditions.

[0039] A curable composition of the invention may include solvent for example to provide a liquid form that is suitable for casting the composition for a desired solid form. For example, when preparing a solid curable composition of the invention the components may be together in a solvent thus allowing the solid curable composition of the invention to be cast in a desired physical form. A desired physical form is a desired solid shape. Additionally, or alternatively a solid curable composition of the invention may be cut to a desired physical form/solid shape. [0040] A solid form has advantages of not running off a substrate like a liquid adhesive may do. Also, it will not be squeezed out like a liquid from between substrates being bonded together.

[0041] Additionally, the film forming polymer component could be blended with other components of the invention and the mixture heated to form an at least partial melt that can be shaped, for example by casting, moulding, extrusion etc.

[0042] Solid curable compositions of the invention, which may be in the form of a film can be considered to have a hybrid cure, which may also be considered to be a dual cure. This hybrid cure/dual cure of solid curable compositions of the invention is a UV- anaerobic cure.

[0043] Solid curable compositions of the invention, for example in the form of an adhesive tape has potentially multiple end-use applications. For example, they may be used to bond together different substrates for example involving hybrid substrate bonding.

[0044] Solid curable compositions of the invention can achieve fast curing and high shear strength.

[0045] Depending on the substrate used, it is possible to cure a solid curable composition of the invention via the following cure mechanisms:

(i) Anaerobically (for example to bond together metal/metal substrates);

(ii) Both UV and anaerobic combined curing (for example to bond together metal/UV-transparent substrate);

(iii) UV irradiation (for example to bond together UV-transparent/UV- transparent substrate).

[0046] Solid curable compositions of the invention show improved bonding on hybrid substrate bonding which would not occur if the dual cure of the solid curable compositions of the invention was not available. So, for example anaerobic bonding may suit bonding to a metal substrate, in particular metal to metal bonding, whereas UV curing may suit bonding to non-metallic substrates, in particular where at least one substrate is a UV transparent non-metallic substrate such as a UV transparent plastics substrate. In such cases UV irradiation sufficient to impart UV cure conditions combined with anaerobic cure conditions can achieve good bond strengths in metal substrate to non-metallic substrate bonding in particular where at least one substrate is a UV transparent non-metallic substrate such as a UV transparent plastics substrate. [0047] The UV irradiation desirably has a wavelength of from about 100 to about 700 nm, such as from about 360 to about 380 nm. [0048] Exposure times for exposure of solid curable compositions of the invention to UV irradiation may be from about 1 to about 300 seconds such as from about 1 to about 10 seconds.

[0049] The UV irradiation desirably has an intensity of from about 1 to about 1000 mW/cm², such as from about 70 to about 650 mW/cm².

[0050] Furthermore, solid curable compositions of the invention demonstrate good bonding for different non-metal substrates combinations for example glass to plastics such as glass-nylon, glass-ABS, glass-polymethyl methacrylate such as Perspex™, and plastics to plastics such as polymethyl methacrylate to polymethyl methacrylate for example Perspex™ - Perspex™, etc. (Perspex™ is a commercially available product which is a solid transparent plastic made of polymethyl methacrylate. ABS is Acrylonitrile Butadiene Styrene plastic.)

[0051] Solid curable compositions of the invention may demonstrate immediate fixture. For example immediate cure may be achieved with UV irradiation. Slower cure may occur with anaerobic cure.

[0052] Solid curable compositions of the invention, which may be in the form of a tape have anaerobic cure, combined UV/anaerobic cure, or just UV activated tape and the cure mechanism(s) can be chosen depending on the substrate(s) to bond.

[0053] Desirably in a solid curable composition of the invention the film forming polymer component comprises at least one functional group that is reactive free radically with an anaerobic monomer. The film forming polymer component crosslinks with the anaerobic monomer.

[0054] The film forming polymer component can include one or more cellulose esters. [0055] Additionally or alternatively the film forming polymer component can include one or more thermoplastic polyvinyl butyral resins.

[0056] Any combination of the above can be used.

[0057] In this respect solid means non-flowable at ambient temperature and with a melting point above about 30°C. Thus, solid does not mean gel. It will be appreciated that not all components of the composition have to be solid. For example it is usual that the curing component curing the anaerobically curable component is typically in liquid form. However whenever such component(s) are present the composition of the invention is formulated so that overall it is a solid.

[0058] In particular there is sufficient film forming polymer present to impart a solid form to the composition.

[0059] Any melting point may be measured by DSC (Differential Scanning Calorimetry) or by ring and ball method, DIN ISO 4625. It is understood that melting may not occur at a single temperature but instead occur over a temperature range. In any event for the purposes of this invention the end point temperature for melting is at or above 30°C - that is when exposed to temperatures below the melting point temperature the composition will turn back to its solid form.

[0060] The molecular weight (Mw) is as determined in accordance with ASTM D5296- 05 (Standard Test Method for Molecular Weight Averages and Molecular Weight Distribution of Polystyrene by High Performance Size-Exclusion Chromatography).

[0061] The film forming polymer desirably includes a reactive group which facilitates free radical cross-linking. Such a free radically active functional group can include at least one -OH group, such as: at least one -OH group; at least one secondary or tertiary CH group, at least one (meth)acrylate group; and at least one acrylamide group and desirably comprises a repeating unit, for example wherein the repeating unit comprises at least one -OH group. Multiple free radically active groups such as -OH, or C-H groups within the backbone of the film forming polymer component is desirable. The presence of such free radically active groups may facilitate cross-linking.

[0062] The film forming polymer component may comprise a solid thermoplastic polyvinyl butyral resin.

[0063] Polyvinyl butyral (PVB) is a thermoplastic polymer prepared by hydrolysis of polyvinyl acetate and subsequent condensation with butyraldehyde. The polymer contains hydroxyl, acetyl and butyraldehyde functional groups and its generic chemical structure is depicted below:

[0064] PVB is commercially available as different grades with varying molecular weight and different hydroxyl, acetyl and butyraldehyde contents i.e., different x, y, z values and which determine their physical and chemical properties. Commercially available solid thermoplastic polyvinyl butyral resins include those sold under the trade name Butvar™ by Eastman Chemical Company, or Mowital™ by Kuraray Europe GmbH. Suitable solid thermoplastic polyvinyl butyral resins include Butvar® B-79, available from Eastman. Butvar® B-79 is a solid thermoplastic polyvinyl butyral resin having a molecular weight of 50,000-80,000 g/mol (size exclusion chromatography with low angle laser light scattering standard) and a softening point in the range of 140-200 °C. Other suitable commercial solid thermoplastic polyvinyl butyral resins may include Butvar® B-72, Butvar® B-74, Butvar® B-76, Butvar® B-90, and Butvar® B-98, available from Eastman.

[0065] Other suitable solid thermoplastic polyvinyl butyral resins include Mowital B30 HH, available from Kuraray. Mowital B30 HH is a solid thermoplastic polyvinyl butyral resin having a molecular weight of 50,000 -70,000 and a softening range of 140-180 °C. Other suitable commercial solid thermoplastic polyvinyl butyral resins may include Mowital B20 H, B30 T, B30 H, B45 H, B60 T, B60 H, and B60 HH.

[0066] The solid thermoplastic polyvinyl butyral resin may have a softening point in the range of from about 50 °C to about 300 °C, suitably from about 100 °C to about 250 °C, preferably from about 140 °C to about 200 °C. The solid thermoplastic polyvinyl butyral resin may act as a film former. The use of a solid thermoplastic polyvinyl butyral resin having a high softening point such as from about 140 °C to about 200 °C is believed to impart the resulting compositions with good thermal resistance, making them able to perform well at high temperatures. For example, solid curable composition of the invention in tape form are suitable for applications at elevated temperatures, such as at 100 °C, 150 °C, or even higher. Softening point may be determined by DSC or by ring and ball method, DIN ISO 4625.

[0067] The solid thermoplastic polyvinyl butyral resin may have a molecular weight Mw in the range of from about 40,000 g/mol to about 250,000 g/mol, suitably in the range of from about 40,000 g/mol to about 170,000 g/mol, such as about 40,000 g/mol to 120,000 g/mol, for example 50,000 g/mol to 80,000 g/mol, wherein the molecular weight Mw is as determined in accordance with ASTM D5296-05 (Standard Test Method for Molecular Weight Averages and Molecular Weight Distribution of Polystyrene by High Performance Size-Exclusion Chromatography).

[0068] The film forming polymer component may alternatively or additionally comprise a cellulose ester, for example an ethylenically unsaturated cellulose ester.

[0069] Such cellulose esters such as ethylenically unsaturated cellulose esters may be prepared by the reaction of (a) a cellulose ester of cellulose and saturated aliphatic monocarboxylic acids having 2 to 4 carbon atoms or aromatic monocarboxylic acids, said cellulose ester having an average of about 0.1 to 2.0, preferably 0.25 to 1.0, unreacted hydroxy groups per anhydroglucose unit, and (b) a polymerizable ethylenically unsaturated compound having an isocyanato group reactive with the hydroxyl groups of the cellulose ester such that the reaction product is substantially free of unreacted isocyanato groups, i.e., preferably containing less than 1.0% unreacted isocyanato groups, more preferably less than 0.5% unreacted isocyanato groups, most preferably no unreacted isocyanato groups, as detected by titration or infrared analysis. Suitably, about 30 to 100 percent, such as 50 to 100 percent, for example 70 to 100 percent of the free hydroxyl groups of the cellulose ester (a) are reacted with the isocyanato groups of the polymerizable ethylenically unsaturated compound (b).

[0070] Suitable reactive cellulose esters include polymerizable high molecular weight cellulosic polymers functionalised with acrylamido groups. Commercially available polymerisable cellulosic resins include those sold under the trade name Jaylink by Bomar Specialty Chemicals. Suitable polymerizable cellulosic polymers include Jaylink JL-106E which is an acrylamidomethyl-substituted cellulose ester polymer with a high degree of acrylamide substitution.

[0071] The film forming polymer component may alternatively or additionally comprise a thermoplastic polyurethane which is activatable by UV radiation, for example a thermoplastic polyurethane that comprises at least one acrylate group, at least one methacrylate group or at least one acrylamide group.

[0072] The composition of the invention may include an initiator (of free radical polymerization) selected from the group consisting of: cumene hydroperoxide ("CHP"), para-menthane hydroperoxide, t-butyl hydroperoxide ("TBH"), t-butyl perbenzoate, benzoyl peroxide, dibenzoyl peroxide, 1 ,3-bis(t-butylperoxyisopropyl)benzene, diacetyl peroxide, butyl 4,4-bis(t-butylperoxy)valerate, p-chlorobenzoyl peroxide, t-butyl cumyl 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-butyl-peroxyhex-3-yne, 4-methyl-2,2-di-t- butylperoxypentane, t-amyl hydroperoxide, 1 ,2,3,4-tetramethylbutyl hydroperoxide and combinations thereof. The initiator of free radical polymerisation may comprise an encapsulated peroxide.

[0073] The anaerobically curable component may be present in an amount from about 5 wt% to about 90 wt% based on the total weight of the solid curable composition, suitably in an amount of from about 10 wt% to about 80 wt%, such as about 70 wt% based on the total weight of the solid curable composition. [0074] The curing component for curing the anaerobically curable component may be present in an amount of from about 0.1 to about 10 wt% such as from about 1 to about 5 wt%, based on the total weight of the solid curable composition.

[0075] The film forming polymer component may be present in an amount of from about 10 wt% to about 50 wt%, based on the total weight of the solid curable composition, suitably in an amount of from about 15 wt% to about 40 wt%, such as from about 15 wt% to about 35 wt%, for example about 30 wt% based on the total weight of the solid curable composition.

[0076] The photoinitiator component of the invention desirably comprises at least one photoinitiator. Photoinitiators available commercially from BASF Chemical, Germany, under the “IRGACURE” and “DAROCUR” tradenames are desirable, specifically “IRGACURE” 184 (1 -hydroxycyclohexyl phenyl ketone), 907 (2-methyl-1-[4- (methylthio)phenyl]-2-morpholino propan-1 -one), 369 (2-benzyl-2-N,N-dimethylamino-1- (4-morpholinophenyl)-1-butanone), 500 (the combination of 1 -hydroxy cyclohexyl phenyl ketone and benzophenone), 651 (2,2-dimethoxy-2-phenyl acetophenone), 1700 (the combination of bis(2,6-dimethoxybenzoyl-2,4,4-trimethyl pentyl phosphine oxide and 2- hydroxy-2-methyl-1-phenyl-propan-1-one) and “DAROCUR” 1173 (2-hydroxy-2-methyl- 1-phenyl-1 -propane) and 4265 (the combination of 2,4,6-trimethylbenzoyldiphenyl- phosphine oxide and 2-hydroxy 2-methyl-1-phenyl-propan-1-one). Of course, combinations of such materials may also be employed herein. The structures of preferred photoinitiators are shown below.

[0077] Irgacure 651 [0080] Irgacure 819

[0081] Irgacure 369

[0082] The photoinitiator component may be present in an amount of from about 0.1 to about 10 wt% such as from about 1 to about 5 wt%, based on the total weight of the solid curable composition.

[0083] A solid curable composition according to the invention may further comprise a cure accelerator. A composition of the invention may also include a cure accelerator, for example saccharin and/or APH.

[0084] Additionally or alternatively the cure accelerator comprises one or more metallocenes, such as ferrocene, suitably, n-butyl ferrocene; and/or a cure accelerator embraced by wherein X is CH2, O, S, NR⁴, CR⁵R⁶ or C=O; R is one or more of hydrogen, alkyl, alkenyl, alkynl, hydroxyalkyl, hydroxyalkenyl, or hydroxyalkynl; R¹ - R⁶ are each individually selected from hydrogen, halogen, amino, carboxyl, nitro, alkyl, alkenyl, alkynyl, hydroxyalkyl, hydroxyalkenyl, hydroxyal kynyl, or alkaryl; R⁷ is hydrogen or CHR⁸R⁹, wherein R⁸ and R⁹ are each individually selected from hydrogen, halogen, amino, carboxyl, nitro, alkyl, alkenyl, alkynyl, hydroxyalkyl, hydroxyalkenyl, hydroxyalkynyl, or alkaryl; and n is 0 or 1.

[0085] A solid curable composition of the invention may be provided in tape form, filament form or in the form of a coating on a substrate.

[0086] The invention also relates to the use of a film forming polymer component that is activatable by UV radiation as a cross-linking component, for example a cross-linker for the anaerobically curable component within an anaerobically curable composition that also comprises a photoinitiator component. The anaerobically curable composition is a solid curable composition due to the presence of the film forming polymer component.

[0087] The anaerobically curable component may be a (meth)acrylate component.

[0088] For example the anaerobically curable component may be a (meth)acrylate monomer component which may be one or more selected from those having the formula:

H₂C=CGCO₂R⁸, wherein G is hydrogen, halogen or alkyl groups having from 1 to 4 carbon atoms, and R⁸ is selected from alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkaryl, alkaryl or aryl groups having from 1 to about 16 carbon atoms, any of which may be optionally substituted or interrupted as the case may be with silane, silicon, oxygen, halogen, carbonyl, hydroxyl, ester, carboxylic acid, urea, urethane, carbonate, amine, amide, sulfur, sulfonate, sulfone and the like.

[0089] Suitably, the anaerobically curable component can be the reaction product of an isocyanate-containing compound, such as phenyl isocyanate, and a hydroxylalkyl (meth) acrylate, such as hydroxyethyl methacrylate (HEMA): which is 2-methacryloxylethyl phenyl urethane with a melting point of about 70-75°C.

[0090] The anaerobically curable component can also be the reaction product of 2 molar equivalents of HEMA with 1 molar equivalent diisocyanates such as isophorone diisocyanate (IPDI), 4,4'-methylenebis(cyclohexyl isocyanate) (HMDI), or 1,5-cyclohexyl diisocyanate (CHDI). For example: which is HEMA-IPDI-HEMA with a melting point of about 72-74°C; which is HEMA-HMDI-HEMA with a melting point of about 75-85°C; which is HEMA-CHDI-HEMA with a melting point of about 75-85°C.

[0091] The anaerobically curable component can also be or include a polyurethane methacrylate resin with a molecular weight >2000 g.mol and with a semi-crystalline polyester polyol backbone. An example of such a resin is given in International patent publication WO 2017/68196A1 and is the reaction product of the polyol known as Dynacoll 7380 with toluene diisocyanate, followed by end capping with HEMA. These resins have a melting point in the range of 50-80°C. Commercially available (meth)acrylated polyurethane resins include those sold under the trade name Lumiset™

[0092] The anaerobically curable component can also be or include novolac vinyl ester resins which are the reaction products of novolac epoxy resins and methacrylate acids. Examples of these resins and their preparation are shown in US Patent No. 9,957,344.

For example where n is an integer between 2-10 and the compound has a melting point of about 70- 75°C.

[0093] Suitably, the curing component for curing the anaerobically curable component comprises one or more selected from the group consisting of 1-acetyl-2- phenylhydrazine, N,N-dimethyl para toluidine, N,N-diethyl para toluidine, N,N-diethanol para toluidine, N,N-dimethyl ortho toluidine, N,N-dimethyl meta toluidine, indoline, 2methylindoline, isoindoline, indole, 1 ,2,3,4-tetrahydroquinoline, 3methyl1 , 2,3,4- tetrahydro-quinoline, 2-methyl-1 ,2,3,4-tetrahydroquinoline, and 1 , 2,3,4- tetrahydroquinoline-4-carboxylic acid, and 1,2,3,4-tetrahydro-benzo(H)quinolin-3-ol.

[0094] A solid curable composition of the invention may comprise a cure accelerator embraced by

wherein X is CH2, O, S, NR⁴, CR⁵R⁶ or C=O; R is one or more of hydrogen, alkyl, alkenyl, alkynl, hydroxyalkyl, hydroxyalkenyl, or hydroxyalkynl; R¹ - R⁶ are each individually selected from hydrogen, halogen, amino, carboxyl, nitro, alkyl, alkenyl, alkynyl, hydroxyalkyl, hydroxyalkenyl, hydroxyal kynyl, or alkaryl; R⁷ is hydrogen or CHR⁸R⁹, wherein R⁸ and R⁹ are each individually selected from hydrogen, halogen, amino, carboxyl, nitro, alkyl, alkenyl, alkynyl, hydroxyalkyl, hydroxyalkenyl, hydroxyal kynyl, or alkaryl; and n is 0 or 1.

[0095] Optionally the cure accelerator can be selected from the group consisting of amines, amine oxides, sulfonamides, metal sources, acids, and mixtures thereof. These may be used in combination with the cure accelerators above.

[0096] Optionally the accelerator/co-accelerator may be selected from the group consisting of triazines, ethanolamine, diethanolamine, triethanolamine, N,N dimethyl aniline, benzene sulphanimide, cyclohexyl amine, triethyl amine, butyl amine, saccharin, N,N-diethyl-p-toluidine, N,N-dimethyl-o-toluidine, acetyl phenylhydrazine, maleic acid, and mixtures thereof.

[0097] The cure accelerator may be

wherein R is one or more of hydrogen, alkyl, alkenyl, alkynl, hydroxyalkyl, hydroxyalkenyl, or hydroxyalkynl; and R¹ and R² are each individually selected from halogen, amino, carboxyl, nitro, alkyl, alkenyl, alkynyl, hydroxyalkyl, hydroxyalkenyl, hydroxyal kynyl, or alkaryl.

[0098] For example the cure accelerator may be selected from one or more of wherein R is as defined above.

[0099] The cure accelerator may be

1 ,2,3,4-tetrahydrobenzo-h-quinolin-3-ol.

[00100] A solid curable composition of the invention may further comprise an initiator of free radical polymerization such as a peroxide.

[00101] The initiator of free radical polymerization is one or more selected from the group consisting of: cumene hydroperoxide ("CHP"), para-menthane hydroperoxide, t-butyl hydroperoxide ("TBH"), t-butyl perbenzoate, benzoyl peroxide, dibenzoyl peroxide, 1,3-bis(t-butylperoxyisopropyl)benzene, diacetyl peroxide, butyl 4,4-bis(t- butylperoxy)valerate, p-chlorobenzoyl peroxide, t-butyl cumyl 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-butyl-peroxyhex-3-yne, 4-methyl-2,2-di-t- butylperoxypentane, t-amyl hydroperoxide, 1,2,3,4-tetramethylbutyl hydroperoxide and combinations thereof. The initiator of free radical polymerisation may comprise an encapsulated peroxide.

[00102] The solid curable composition of the invention may further comprise a cure accelerator in addition to or instead of those described above. For example, the cure accelerator may comprise one or more metallocenes such as ferrocene, suitably, n-butyl ferrocene. Advantageously, the presence of a cure accelerator facilitates cure of the solid curable composition of the invention on “non-active” or “passive” substrates, such as plastic substrates.

[00103] A solid curable composition of the invention may further comprise at least one solvent. The use of a solvent may be beneficial, for example, for formulation or dispensing purposes. Suitably, the at least one solvent may be selected from the group comprising: ethyl acetate, tetra hydrofuran, dichloromethane, chloroform, or a combination thereof. [00104] However, wherever weight percentages are used, they are based on the total weight of the composition without solvent.

[00105] A solid curable composition of the invention may further comprise one or more components selected from polyesters, polyurethanes, polyimides, siloxane polyimides, polyamides, rubbers such as styrene-butadiene rubber (SBR), nitrile rubber (NBR), carboxy-terminal nitrile rubber (CTBN), ethylene-propylene-diene monomer copolymer (EPDM), polybutadiene rubber, polyisoprene rubber, poly(styrene butadienestyrene) block copolymer (SBS), poly(styrene isoprene-styrene) block copolymer (SIS), styrene-b-ethylene-co-butylene-b styrene block copolymer (SEBS), styrene-b-ethylene- co-propylene-b-styrene block copolymer (SEPS), ethylene co-vinyl acetate, as well as acrylic polymers, all by way of example. Suitable materials include rubber materials sold under the trade name Vamac™ rubbers (for example DP and Ultra DX grades), or the trade name Hypalon™ (chlorosulphonated polyethylene rubber).

[00106] Additionally or alternatively the solid curable composition of the invention may further comprise one or more components selected from solid anaerobically curable monomers and/or solid anaerobically curable resins. The resin component may be selected from: (meth)acrylated polyurethane resins with a molecular weight of about 2,000 g/mol or higher; novolac resins with a molecular weight of about 2,000 g/mol or higher; (meth)acrylated polyester resins with a molecular weight of about 2,000 g/mol or higher; and combinations thereof. For example the resin component may have a molecular weight in the range from 2,500 to 40,000 g/mol. The resin component may have a melt viscosity of from about 0.5 to about 20 Pa.s at 80°C. The anaerobically curable monomer desirably comprises at least one acrylate or methacrylate ester group.

[00107] Such additional components can be selected based on whether they contain functionality reactive towards an anaerobic adhesive via free radical reaction/crosslinking (eg., active CH, ene unsaturation, allyl, acrylate, methacrylate, acrylamido etc), or they can be derivatised to incorporate such reactive functionality.

[00108] The composition of the invention may include (as a resin) a (long chain) meth(acrylated) polyurethane for example: fastm where n is an integer from 2 to 10 for example a compound of the above formula having a molecular weight of about 6,000 g/mol may have a melting point of 75 to 85°C.

[00109] The composition of the invention may include (as a film-forming resin) a novolac vinyl ester for example where n is an integer from 2-10. For example a compound of the above formula having a molecular weight of about 6,000 g/mol may have a melting point of 75 to 85°C.

[00110] The composition of the invention may include (as solid anaerobically curable monomer): which is 2-methacryloxyethylphenylurethane with a melting point of about 70-75°C.

[00111] The composition of the invention may include (as solid anaerobically curable monomer): bisphenol A dimethacrylate: which has a melting point of approximately 72 to 74°C.

[00112] The composition of the invention may include (as solid anaerobically curable monomer): diisocyanates capped with hydroxyethyl methacrylate such as: which is HEMA-IPDI-HEMA with a melting point of about 72-74°C: or which is HEMA-HMDI-HEMA with a melting point of about 75-85°C: or which is HEMA-6HXDI-HEMA with a melting point of about 75-85°C: or which is Glycerol Dimethacrylate-6HXDI-Glycerol Dimethacrylate with a melting point in the range from about 75 to about 85°C.

[00113] Suitably, solid curable composition of the invention may be provided in any suitable solid form including tape form, filament form or as a coating applied to a substrate including for example a filament or thread made from another material such as a nylon or polyester thread. A solid curable composition of the invention may be provided in stick form. A tape or filament of the solid curable composition of the invention may be less than 100 microns (pm) thick. A tape or filament may be applied by winding i.e. in a similar manner to current PTFE tape or thread-sealing cord used to seal joints in pipework. It will be appreciated that the solid form can be to a desired pattern, layout or form including in the form of a stick, a tape, a filament, a gasket or a patch. The composition in its solid form such as tape form, or filament form may have sufficient integrity to be handled without breaking. The composition in its solid form such as tape form or filament form can be applied to substrates, for example metal bolts, at room temperature. The composition in its solid form such as tape form or filament form may be capable of thermal resistance at temperatures of at least 150 °C, for example at least 180 °C, for example 200 °C. This means that the composition is robust enough to maintain performance at the temperatures of common industrial environments. Even at elevated temperatures, the composition in its solid form such as tape form, or filament form may be non-tacky and dry to touch such that a carrier, such as a release liner, is not required. The composition in tape form, or filament may be rolled up onto itself and will not adhere to itself as it is non-tacky and dry to touch. Alternatively the tape form, or filament form may comprise a solid curable composition of the invention and one or more release liners. For example, when the temperature at which the composition is to be stored is above 40°C a release liner may be useful as at temperatures above 40°C the non-tacky composition may become tacky and may adhere to itself. As mentioned above the solid curable composition of the invention may also be any suitable solid form including tape form, filament form, stick form, or as a (solid, dry to touch) coating applied to a substrate including for example a filament or thread made from another material such as a nylon or polyester thread.

[00114] This invention describes a dual curing UV anaerobic adhesive tape composition whereby, depending on the substrate combination and the substrate UV transparency/opacity, it can be cured either anaerobically (metal to metal, non-UV transparent), or by UV and anaerobic cure (metal to UV transparent substrate), or solely by UV (UV transparent to UV transparent substrate). Excellent bond strength is achieved in all cases (e.g.: Stainless steel (SS)/Mild steel (MS), (polyvinyl chloride)PVC, PC (polycarbonate) medical grade, Perspex^TM(Px), Glass lap shears). This invention enables greater flexibility in terms of bonding various substrates combinations including hybrid substrates (e.g., metal-plastic, metal-glass, etc.)

[00115] The invention also relates to a tape comprising a solid curable composition of the invention and one or more release liners. The solid curable composition is carried on the release liner.

[00116] The invention also relates to a substrate such as a threaded article, such as threaded bolt with a solid curable composition according to the invention applied to it.

[00117] The invention also relates to an assembly comprising two substrates bonded together by the cure product of a solid curable composition according to the invention.

[00118] The invention also relates to a tape comprising a solid curable composition of the invention and one or more release liners.

[00119] The invention also relates to a threaded member comprising at least one threaded face, wherein said at least one threaded face comprises a solid curable composition of the invention, optionally wherein the solid curable composition of the invention is in tape form, filament form or in the form of a coated substrate, and optionally wherein said a solid curable composition of the invention in tape form, filament form or in the form of a coated substrate is applied to the threaded face, for example, by wrapping said tape at least partially around said threaded face..

[00120] The invention also relates to a method of manufacturing a threaded member comprising a threadlocking composition, comprising:

(i) providing at least one threaded member comprising at least one threaded face,

(ii) applying to said at least one threaded face, a solid curable composition of the invention.

[00121] In this method of manufacturing a threaded member, the solid curable composition of the invention may be is in tape form, filament form, stick form, or in the form of a coated substrate, and optionally wherein the solid curable composition of the invention in tape form, filament form or in the form of a coated substrate is wrapped at least partially around the at least one threaded face of the threaded member.

[00122] The invention also relates to a method of assembling threaded members comprising:

(i) providing a first threaded member, comprising at least one threaded face;

(ii) applying a solid curable composition of the invention to said at least one threaded face;

(iii) providing a second threaded member capable of matingly engaging said first threaded member;

(iv) matingly engaging said first and second threaded members and thereby exposing said solid curable composition of the invention to an anaerobic environment for a time sufficient for said solid curable composition of the invention to cure between said first and second threaded members.

[00123] In such a method the solid curable composition of the invention may be in tape form, filament form or in the form of a coated substrate and optionally the solid curable composition of the invention in tape form, filament form or in the form of a coated substrate is wrapped at least partially around said at least one threaded face. [00124] The invention also relates to a method for manufacturing a tape, thread, or fibre for threadlocking comprising the steps of: (i) mixing at least one film forming polymer component, and solvent, optionally wherein the solvent is selected from tetra hydrofuran, dichloromethane, chloroform, ethyl acetate, or a combination thereof;

(ii) mixing therewith: a liquid anaerobically curable component, a curing component for curing the anaerobically curable components; optionally, adding additives to the mixture; so as to form an anaerobically curable composition;

(iii) forming the mixture into a desired form for example by casting and/or applying the mixture to a carrier such as a threaded article or a release liner;

(iv) removing the solvent and/or allowing the solvent to evaporate, to thereby form a tape, thread, or fibre comprising the solid curable composition and optionally a carrier.

Detailed Description

[00125] The solid curable composition of the invention may be prepared as follows.

[00126] A formulation is prepared by dissolving a film former, such as a film forming polymer, in a suitable solvent along with an anaerobically curable monomers, stabilizers, photo-initiator, rheology modifiers, redox cure system (e.g. CHP/APH, saccharin combination). Here the components are mixed, and the mixture is cast onto a support such as backing film. The solvent is then removed by letting it evaporate or driving it off. This allows a uniform solid form such as a film to be prepared.

[00127] The following methods describe how to prepare the bonded substrate based on the curing mechanism:

• Anaerobic bonds (metal/metal substrate); the area to be bonded is coated with the tape, a second metal substrate is applied and clamped. The bonded assembly is left to cure anaerobically at room temperature for 24 hours.

• Both UV and anaerobic combined bonds (metal/UV-transparent substrate); the area to be bonded is coated with the tape, a UV- transparent substrate is applied on top, the assembled bond is irradiated for a required time and irradiation intensity. The bond can be left at room temperature for combined light-anaerobic curing which increases the shear strength over time. UV curing bonds (UV-transparent/UV-transparent substrate); the area to be bonded is coated with the tape, a second UV-transparent substrate is applied on top, the assembled bond is irradiated for a required time and irradiation intensity.

[00128] The following formulations are prepared. Pre-cast is the formulation including solvent which is then cast to form a tape.

Table A

*Components:

**Formulation A = Butvar B-79, Formulation B = Butvar B-98, Formulation C = Mowital B30 HH, Formulation D = Mowital B60 H, Formulation E = Jaylink JL-106E, Formulation F = TPU 50:50 blend of Pearlbond 100/Pearlbond 106)

***Ethyl Acetate

[00129] Tape preparation via Elcometer film casting

• Position a suitable backing tape/support (e.g., siliconized PET sheet) on the Elcometer

• Adjust the height of the adjustable film applicator (e.g., 150 urn)

• Pour the formulation on the support in line with the adjustable film applicator

• Start the equipment at a suitable speed (1-10 in the instrument)

• Once the film is cast, let the solvent evaporate • Eventually, apply a second backing tape/support liner to store the sample. Protect both formulation and tape from natural and artificial light sources.

[00130] Testing method:

• Remove one of the backing tapes/supports

• Apply the tape on a suitable substrate (either metal, non-metal, UV- transparent)

• Apply the second substrate (possible combinations are either non- metal/UV-transparent; metal/UV transparent; UV-transparent/UV- transparent; metal/metal)

• Curing time and method (either UV, anaerobic, or hybrid UV/Anaerobic) depends on the substrate chosen.

[00131] Control I is a Solid Anaerobic Tape as per Example\Composition 4 of International (PCT) patent application no. PCT/EP2023/071594.

[00132] Control II is the anaerobic adhesive sold under the brand name

Loctite® AA3510 (liquid) and is available from Henkel Ireland Limited in Tallaght, Dublin, Ireland.

[00133] Unless otherwise stated, in the experiments below, UV irradiation is carried out utilising the Henkel UVALOC™ 1000 UV machine.

[00134] Unless otherwise stated, in the experiments below shear strength is determined by the standard ISO 4587.

[00135] Unless otherwise stated, in the experiments below Retain % or Retain (%) is the percentage of the initial shear strength retained after heat ageing.

[00136] In relation to temperature in the experiments below, RT is room temperature.

[00137] Table 1 Anaerobic cure SS/SS, MS/MS.

* CF = Cohesive Failure; AF = Adhesive Failure; SF = Substrate Failure [00138] Table 2 Dual Cure SS/Px.

* CF = Cohesive Failure; AF = Adhesive Failure; SF = Substrate Failure

[00139] Table 3 UV cure Px/Px.

* CF = Cohesive Failure; AF = Adhesive Failure; SF = Substrate Failure [00140] Table 4 UV Cure Glass-Glass

* CF = Cohesive Failure; AF = Adhesive Failure; SF = Substrate Failure

[00141] Table 5

CF = Cohesive Failure; AF = Adhesive Failure; SF = Substrate Failure [00142] **A rapid increase of temperatures was observed during the experiment, going from 54.3 °C and reaching a maximum of 79.4 °C mildly deforming the plastic during the curing process. This is caused by heat generated by the UV light source.

[00143] Table 6 below includes additional formulations B, C, D, E and F containing different film formers. As indicated above the formulations are as set out in Table A above but formulations A, B, C, D, E and F each have a different film former as follows: Formulation A = Butvar B-79, Formulation B = Butvar B-98, Formulation C =

Mowital B30 HH, Formulation D = Mowital B60 H, Formulation E = JayLink 106E, Formulation F = TPU blend (Pearlbond 100/Pearlbondl06 = 50/50).

[00144] Table 6

[00145] In Table 6 the additional formulations based on Butvar B-98, Mowital B30 HH, Mowital B60 H, Jaylink JL-106E are compared to Control I (a solid anaerobic tape that is not UV active - see above) and Control II (a commercial liquid UV anaerobic adhesive that does not contain the solid polymerizable film former - see above). Formulation F is based on a thermoplastic polyurethane (TPU) film former that does not contain UV activatable functional groups and does not polymerize under UV cure conditions. (Pearlbond™ is a commercially available thermoplastic polyurethane.)

[00146] Table 7 below includes additional heat age testing data for Formulation A in comparison to Control II.

Table 7 (Heat ageing test):

[00147] It will be noted from Table 7 that the formulation of the invention performs better than the control in each test. So compositions of the invention perform well in terms perform well in terms of bond shear strength after aging at elevated temperature for various time intervals.

[00148] Table 8 below includes additional heat age testing data for Formulations A, C and D in comparison to Control II. This time different (harsher) ageing conditions are utilised as set out in Table 8. Table 8 (Heat ageing tests):

[00149] It will be noted from Table 8 that the formulations of the invention performs at least as well as the corresponding control in each test, and in the majority of cases better than the control. So compositions of the invention well in terms perform well in terms of bond shear strength after aging at elevated temperature for various time intervals and in humid conditions.

[00150] The words “comprises/comprising” and the words “having/including” when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components but do not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[00151] It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

Claims

1 . A solid curable composition that is both UV curable and anaerobically curable, the solid curable composition comprising:

(i) an anaerobically curable component;

(ii) a curing component for curing the anaerobically curable component;

(iii) a film forming polymer component that is activatable by UV radiation; and

(iv) a photoinitiator component.

2. A solid curable composition according to Claim 1 wherein the film forming polymer component functions as a cross-linker during cure of the solid curable composition.

3. A solid curable composition according to any preceding claim wherein the film forming polymer component comprises at least one free radically active functional group such as: at least one -OH group; at least one secondary or tertiary CH group, at least one (meth)acrylate group; and at least one acrylamide group.

4. A solid curable composition according to any preceding claim wherein the film forming polymer component comprises a solid thermoplastic polyvinyl butyral resin.

5. A solid curable composition of claim 4, wherein the solid thermoplastic polyvinyl butyral resin has a molecular weight Mw in the range of from about 40,000 g/mol to about 250,000 g/mol, suitably in the range of from about 40,000 g/mol to about 170,000 g/mol, such as about 40,000 g/mol to 120,000 g/mol, for example 50,000 g/mol to 80,000 g/mol, wherein the molecular weight Mw is as determined in accordance with ASTM D5296-05.

6. A solid curable composition according to any preceding claim wherein the film forming polymer component comprises a cellulose ester, for example an ethylenically unsaturated cellulose ester.

7. A solid curable composition according to any preceding claim wherein the film forming polymer component comprises a thermoplastic polyurethane which is activatable by UV radiation, for example a thermoplastic polyurethane that comprises at least one acrylate group, at least one methacrylate group or at least one acrylamide group.

8. A solid curable composition according to any preceding claim further comprising an initiator which is one or more selected from the group consisting of: cumene hydroperoxide ("CHP"), para-menthane hydroperoxide, t-butyl hydroperoxide ("TBH"), t-butyl perbenzoate, benzoyl peroxide, dibenzoyl peroxide, 1 ,3-bis(t- butylperoxyisopropyl)benzene, diacetyl peroxide, butyl 4,4-bis(t- butylperoxy)valerate, p-chlorobenzoyl peroxide, t-butyl cumyl 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-butyl-peroxyhex-3-yne, 4-methyl-2,2- di-t-butylperoxypentane, t-amyl hydroperoxide, 1 ,2,3,4-tetramethylbutyl hydroperoxide and combinations thereof.

9. A solid curable composition according to Claim 8 wherein the initiator is a peroxide.

10. A solid curable composition according to any preceding claim wherein the anaerobically curable component is present in an amount from about 5 wt% to about 90 wt% based on the total weight of the solid curable composition, suitably in an amount of from about 10 wt% to about 80 wt%, such as about 70 wt% based on the total weight of the solid curable composition.

11. A solid curable composition of any preceding claim, wherein the curing component for curing the anaerobically curable component is present in an amount of from about 0.1 to about 10 wt% such as from about 1 to about 5 wt%, based on the total weight of the solid curable composition.

12. A solid curable composition of any preceding claim, wherein the film forming polymer component is present in an amount of from about 10 wt% to about 50 wt%, based on the total weight of the solid curable composition, suitably in an amount of from about 15 wt% to about 40 wt%, such as from about 15 wt% to about 35 wt%, for example about 30 wt% based on the total weight of the solid curable composition.

13. A solid curable composition of any preceding claim, wherein the photoinitiator component is present in an amount of from about 0.1 to about 10 wt% such as from about 1 to about 5 wt%, based on the total weight of the solid curable composition.

14. A solid curable composition according to any preceding claim, further comprising a cure accelerator, for example saccharin and/or APH.

15. A solid curable composition according to claim 14, wherein the cure accelerator comprises one or more metallocenes, such as ferrocene, suitably, n-butyl ferrocene; and/or a cure accelerator embraced by wherein X is CH2, O, S, NR⁴, CR⁵R⁶ or C=O; R is one or more of hydrogen, alkyl, alkenyl, alkynl, hydroxyalkyl, hydroxyalkenyl, or hydroxyalkynl; R¹ - R⁶ are each individually selected from hydrogen, halogen, amino, carboxyl, nitro, alkyl, alkenyl, alkynyl, hydroxyalkyl, hydroxyalkenyl, hydroxyal kynyl, or alkaryl; R⁷ is hydrogen or CHR⁸R⁹, wherein R⁸ and R⁹ are each individually selected from hydrogen, halogen, amino, carboxyl, nitro, alkyl, alkenyl, alkynyl, hydroxyalkyl, hydroxyalkenyl, hydroxyalkynyl, or alkaryl; and n is 0 or 1.

16. A solid curable composition according to any preceding claim provided in tape form, filament form, stick form, or in the form of a coating on a substrate.

17. Use of a film forming polymer component that is activatable by UV radiation as a cross-linking component, for example a cross-linker for the anaerobically curable component within an anaerobically curable composition that also comprises a photoinitiator component.

18. Use according to Claim 17 wherein the anaerobically curable composition is a solid curable composition due to the presence of the film forming polymer component.

19. A tape comprising a solid curable composition according to any of Claims 1 to 16 and one or more release liners.

0. A substrate such as a threaded article, such as threaded bolt with a solid curable composition according to any of Claims 1 to 16 applied to it.

21. An assembly comprising two substrates bonded together by the cure product of a solid curable composition according to any of Claims 1 to 16.