Oxidation-reduction curable composition and method for manufacturing the same

Abstract

A redox-curable composition, a method for preparing the same, and uses thereof are disclosed. The redox-curable composition is useful as a pre-coating adhesive. The redox-curable composition is solid at room temperature and can be heated for application to a substrate and cooled on said substrate to form a tack-free adhesive layer, which can be activated by mating with another substrate and exposing to an anaerobic environment when required. The composition is particularly suitable for manufacturing composite products, such as mobile phones, computers, and circuits.

Description

Technology Field

[0001] The present invention relates to a curable composition that can be pre-applied to an article, for example, in the form of a non-mobile and substantially non-stick coating. Accordingly, the article can be conveniently handled, packaged, transported, and stored for a long period, and then the coating can be induced to cure at a selected time. A curable composition that undergoes anaerobic curing is of particular interest. A composition that can be pre-applied to an article in the form of a non-mobile and substantially non-stick coating and subsequently anaerobic cured is of interest. One end-use application of such a composition is in the adhesion of components of mobile phones and / or portable devices. Background Technology

[0002] Anaerobic curing compositions are generally well known. For example, see the literature [RD Rich, "Anaerobic Adhesives" in Handbook of Adhesive Technology, 29, 467-79, A. Pizzi and KL Mittal, eds., Marcel Dekker, Inc., New York (1994)] and the references cited therein. Their uses are numerous, and new application areas are constantly being developed.

[0003] Anaerobic adhesive systems are those that 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 widely known for their ability to remain in a non-polymerized liquid state in the presence of oxygen and to cure into a solid state when oxygen is removed.

[0004] Often, anaerobic adhesive systems comprise resin monomers terminated by polymerizable acrylate esters derived according to known urethane chemistry, such as methacrylate, ethyl acrylate, and chloroacrylate esters [e.g., polyethylene glycol dimethacrylate and urethane-acrylate, e.g., U.S. Patent No. 3,425,988 (Gorman)]. Other components typically present in an anaerobic curable adhesive composition include an initiator, such as an organic hydroperoxide, e.g., cumene hydroperoxide, tertian butyl hydroperoxide, etc., an accelerator that increases the curing rate of the composition, and a stabilizer, e.g., quinone or hydroquinone, included to help prevent premature polymerization of the adhesive due to the decomposition of the peroxy compound.

[0005] A curing-inducing composition desirable for inducing and promoting anaerobic curing may comprise one or more of saccharin, toluidine, such as N,N-diethyl-p-toluidine ("DE-pT") and N,N-dimethyl-o-toluidine ("DM-oT"), and acetylphenylhydrazine ("APH") together with maleic acid. See, for example, 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 curing accelerator components in anaerobic adhesive curing systems. In fact, many of the LOCTITE®-brand anaerobic adhesive products currently available from Henkel Corporation use saccharin alone or both saccharin and APH.

[0007] Anaerobic curable adhesive compositions also typically include chelating agents, such as ethylenediaminetetraacetic acid (EDTA), used to sequester metal ions.

[0008] The preparation of an anaerobic curable composition containing an anaerobic curable component typically involves a liquid carrier component. Thus, the composition is typically in liquid form and can be dispensed, for example, by an applicator. For use, the anaerobic curable component is applied by a suitable applicator to form a layer or coating on a surface. Often, the anaerobic curable composition is applied as beads, for example, as continuous beads, to form a gasket.

[0009] Anaerobic curable materials often remain wet even after application until they are exposed to anaerobic conditions suitable for curing. For example, in many cases, anaerobic curable compositions contain liquid monomers.

[0010] Even if an anaerobic curable composition can be dried to some extent, for example by evaporation (by drying it or allowing it to dry for a set period), the material often remains in a wet and adhesive state. This results in potential contamination by anything coming into contact with the article to which the material is applied, and also in unwanted removal of the applied material. Due to the latter problem, the integrity of any bond or seal subsequently formed by the anaerobic curable composition may be potentially compromised, because an insufficient amount may remain to form the desired bond or seal.

[0011] Of course, even if the liquid carrier material is the liquid monomer itself, it will remain in liquid form until anaerobic curing. Therefore, these compositions may be applied onto a substrate and exposed to anaerobic conditions, but they will remain in a wet state or at least adhesive state until curing.

[0012] In the past, fluidity was reduced by adding additional components, such as thickeners, to the material, but because other components are liquids, the overall composition maintains fluidity and / or adhesiveness to some extent.

[0013] If a liquid composition is distributed to a location other than a horizontal surface, dripping and dripping occur. There have been numerous attempts to incorporate materials into liquid anaerobic curable compositions to form non-flowing or at least more viscous adhesives. This is also important in relation to threadlockers. See, for example, U.S. Patent No. 6,451,927.

[0014] U.S. Patent Application Publication No. 2004 / 0228998 relates to a curable film preform composition. The said patent describes a curable preform comprising a curable liquid precursor having a polymer powder mixed therewith such that the resulting preform has a tensile strength of more than 1 pound per square inch. The exemplified preform film is formed by combining polyethylene glycol dimethacrylate anaerobic adhesive with polymethyl methacrylate having an average particle size of about 61 micrometers, a glass transition temperature of 90°C, and a viscosity of 325 cubic centimeters per gram. A pourable mixture is produced by mixing, heating it to 82°C for 10 minutes, and subsequently cooling it to 20°C to provide a stretchable and slightly tacky preform. The curable preform is formed into a film and can be cut into a desired shape. Because the composition is tacky, it is not suitable for use in pre-coating applications. It would be desirable to provide a tack-free adhesive composition that can be pre-applied to a part, said part can subsequently be transported without the risk of contamination or premature curing of the adhesive, and said part having the pre-applied tack-free adhesive can subsequently be bonded to another part when needed.

[0015] U.S. Patent Application Publication No. 2007 / 0021533 relates to an encapsulated curable adhesive composition for use as a structural adhesive. The adhesive composition comprises a first set of microcapsules surrounding a first-part curing agent comprising a monomer and an initiator. The composition further comprises a second-part curing agent. The second-part curing agent comprises an activator and a catalyst. At least the activator of the second-part curing agent is preferably encapsulated in the second set of microcapsules. Reactive contact between the monomer and the first-part curing agent and the second-part curing agent is achieved by exuding the contents of each capsule through the rupture of the microcapsules by reactive contact. The composition is suitable for forming a tack-free drying adhesive. However, the composition is not suitable for high-performance bonding of a wide variety of substrates.

[0016] U.S. Patent No. 9,305,892 relates to an adhesive composition for a pre-coated underfill sealant comprising: (a) a radically polymerizable monomer having one or more functional groups selected from the group consisting of vinyl groups, maleimide groups, acryloyl groups, methacryloyl groups, and allyl groups; (b) a polymer having polar groups; (c) a filler; and (d) a thermal radical initiator. The adhesive composition may be in liquid form or film form. In the case of film form, the adhesive composition may be laminated to a support tape, and then the adhesive composition will be B-stage processed. B-stage processing refers to heating the adhesive composition to the extent that the adhesive composition dries out by the volatilization of any solvent, i.e., to the extent that it becomes non-sticky, although each component contained in the composition does not initiate a reaction (curing) prior to it. In other cases, B-stage processing of the adhesive to a non-sticky state is achieved by partial curing or condensation.

[0017] In the manufacture of composite products comprising various components, for example, in the manufacture of mobile phones, televisions, computers, etc., which include particularly electronic circuits, chipboards, mounting substrates, and display devices, the manufacture of the components often takes place at a location different from where the final product assembly is performed. Using a tack-free adhesive advantageously enables the pre-application of a curable adhesive to the components, and these components can subsequently be transported to another location without concern for adhesive contamination. This would not be easily achieved using a tack-free curable adhesive. Therefore, it is highly desirable to provide a curable adhesive composition that remains stable in an uncured, tack-free state and can be activated when subsequently required. Furthermore, it would also be highly advantageous to provide such an adhesive that enables bonding of various substrate types, for example, metal-to-metal bonding, metal-to-plastic bonding, glass-to-glass bonding, glass-to-metal bonding, glass-to-plastic bonding, and / or plastic-to-plastic bonding. Furthermore, it is particularly desirable to provide a composition suitable for high-performance bonding. These and other requirements are met by the compositions disclosed herein.

[0018] In one aspect, the present invention provides a redox curable composition comprising the following:

[0019] Liquid (meth)acrylate monomer component;

[0020] A solid thermoplastic polyurethane resin having a molecular weight in the range of 40,000 g / mol to 100,000 g / mol and a melting point in the range of 40℃ to 80℃;

[0021] A solid curable polyurethane (meth)acrylate resin having a molecular weight in the range of 5,000 g / mol to 35,000 g / mol and a melting point in the range of 50°C to 80°C; and

[0022] Curing component for curing liquid (meth)acrylate monomer components.

[0023] Advantageously, the composition of the present invention may be applied to a substrate in a molten state and solidified on the substrate, for example, to form a tack-free dry film. Advantageously, once the curable composition is applied to the substrate, it becomes non-flowing and solidifies from a molten state within a period of about 5 minutes at room temperature. An assembly may be formed by fitting the substrate coated with the composition of the present invention to another substrate, and curing may be initiated by melting the adhesive when required and applying heat to initiate redox curing. The composition may be cured under anaerobic conditions, that is, the redox curable composition may be an anaerobic curable composition. Curing of the anaerobic composition may be carried out by exposing said composition to an anaerobic environment.

[0024] Solid thermoplastic polyurethane resins have a molecular weight in the range of 40,000 g / mol to 100,000 g / mol and a melting point in the range of 40°C to 80°C. When the molecular weight is less than about 40,000 g / mol, the cured composition tends to be brittle. When the molecular weight range exceeds about 100,000 g / mol, the composition tends to be tacky and it is difficult to achieve tack-free drying.

[0025] Solid curable polyurethane (meth)acrylate resins have a molecular weight in the range of 5,000 g / mol to 35,000 g / mol and a melting point in the range of 50°C to 80°C. The above temperature range is optimal for redox curable components, particularly those containing peroxides.

[0026] The liquid (meth)acrylate monomer may be present in an amount of about 10 wt% to about 60 wt% based on the total weight of the curable composition, for example, in an amount of about 15 wt% to about 55 wt% based on the total weight of the curable composition, and suitably in an amount of about 25 wt% to about 50 wt% based on the total weight of the curable composition.

[0027] The solid thermoplastic polyurethane resin may be present in an amount of about 5 wt% to about 40 wt% based on the total weight of the curable composition, for example, in an amount of about 7.5 wt% to about 30 wt% based on the total weight of the curable composition, in an amount of about 10 wt% to about 20 wt% based on the total weight of the curable composition, and suitably in an amount of about 10 wt% to about 18 wt% based on the total weight of the curable composition. Compositions having the solid thermoplastic polyurethane resin specified herein in an amount of less than about 5 wt% tend to be brittle, and poor structural bonding and solid formation characteristics are observed. Compositions having the solid thermoplastic polyurethane resin in an amount of more than about 40 wt% tend to have less effective adhesive characteristics when cured. The redox curable composition of the present invention achieves optimal tack-free drying characteristics in an uncured state when the amount of solid thermoplastic polyurethane resin is present in the composition in an amount of about 10 wt% to about 20 wt%.

[0028] Solid curable polyurethane (meth)acrylate resin is present in an amount of about 20 wt% to about 70 wt% based on the total weight of the curable composition, for example, in an amount of about 30 wt% to about 65 wt% based on the total weight of the curable composition, and suitably in an amount of about 40 wt% to about 60 wt% based on the total weight of the curable composition. Compositions containing less than about 20 wt% of solid curable polyurethane (meth)acrylate resin tend to be more liquid and are more difficult to form a tack-free drying redox curable composition. Compositions containing more than about 70 wt% of solid curable polyurethane (meth)acrylate resin tend to have less effective adhesive properties. When the redox curable composition contains solid curable polyurethane (meth)acrylate resin in an amount of about 30 wt% to about 65 wt%, optimal drying time and adhesive performance are achieved.

[0029] A curing component for curing a liquid (meth)acrylate monomer component may be present in an amount of about 0.1 to about 10 weight%, for example about 1 to about 5 weight%, for example about 5 weight%, based on the total weight of the composition, and / or the curing component includes a peroxide.

[0030] The liquid (meth)acrylate monomer component may be one or more selected from those having the following chemical formulas:

[0031] H2C=CGCO2R 8 ,

[0032] Here, G can be hydrogen, a halogen, or an alkyl group having 1 to 4 carbon atoms, and R 8The group may be selected from alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkalyl, alkalyl or aryl groups having 1 to about 16 carbon atoms, and any of these may optionally be substituted or interposed with silane, silicon, oxygen, halogen, carbonyl, hydroxyl, ester, carboxylic acid, urea, urethane, carbonate, amine, amide, sulfur, sulfonate, sulfone, etc.

[0033] The curing agent may be 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, 2-methylindoline, isoindoline, indole, 1,2,3,4-tetrahydroquinoline, 3-methyl-1,2,3,4-tetrahydroquinoline, 2-methyl-1,2,3,4-tetrahydroquinoline, and 1,2,3,4-tetrahydroquinoline-4-carboxylic acid.

[0034] The composition of the present invention may further include an initiator for free radical polymerization, such as a peroxide.

[0035] The initiators for free radical polymerization are cumene hydroperoxide ("CHP"), para-menthan 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-phosphorus, 4-methyl-2,2-di-t-butylperoxypentane, It may be one or more selected from the group consisting of t-amyl hydroperoxide, 1,2,3,4-tetramethylbutyl hydroperoxide and combinations thereof.

[0036] The free radical hardening-inducing component may include encapsulated peroxides.

[0037] The composition of the present invention may further comprise a curing accelerator. Advantageously, the presence of the curing accelerator enables the curing of the composition of the present invention on a "non-active" or "passivated" substrate, such as a plastic substrate. Furthermore, the presence of the curing accelerator enables curing through the volume of the adhesive composition when a bonding gap exists between the substrates to be bonded.

[0038] Suitably, the curing accelerator may include one or more metallocenes, such as ferrocene, suitably n-butyl ferrocene. A particularly useful curing accelerator is benzoyl cyclohexyl thiourea.

[0039] The compositions of the present invention can be applied in any manner. One advantage is that the compositions of the present invention can be manufactured and / or applied to a substrate in a manner that does not require the use of a solvent. Thus, a solvent—an organic solvent or water—is not required. This avoids the need for a liquid carrier for the composition. The compositions of the present invention are essentially dry, which consequently entails advantages in handling. For example, the compositions of the present invention will flow in the form of fine particles, and a liquid carrier is not required, nor is the drying removal of a solvent or water required to achieve application to a substrate.

[0040] Therefore, dry handling of the product is not only achievable but also advantageous, for example, on a production line. The composition of the present invention will dry even when applied (to a substrate). A tack-free dry product is desirable in terms of handling to eliminate contamination, defacement, spills, loss of the composition from the substrate, etc. Advantageously, the composition of the present invention can be used to form a pre-applied tack-free dry adhesive on a substrate, for example, by heating a curable composition from its solid state to a molten state, then applying the molten curable composition to a substrate at room temperature, and allowing the molten curable composition to cool and solidify on the substrate, thereby forming a pre-applied adhesive on the substrate. The curable composition becomes tack-free from its molten state within a period of less than about 5 minutes after being applied to the substrate at room temperature, suitably within a period of about 30 seconds to 300 seconds, for example, within a period of about 30 seconds to 120 seconds.

[0041] The composition of the present invention can have many end-use applications, just like conventional anaerobic curing compositions.

[0042] It will be recognized that since the compositions of the present invention are solids, they can be provided in any designed form / shape.

[0043] Another aspect of the present invention provides a cured composition formed by curing the curable composition of the present invention claimed herein. Suitably, the curable composition may be cured by exposure to an anaerobic environment. The curable composition may be cured by exposure to an anaerobic environment for a period ranging, for example, from about 1 minute to about 30 minutes, e.g., from about 1 minute to about 20 minutes. Optionally, the curable composition may be cured within a temperature range of about 40°C to about 100°C. For example, the curable composition may be cured within a temperature range of about 40°C to about 100°C by exposure to an anaerobic environment for a period ranging from about 1 minute to about 30 minutes.

[0044] In another aspect, the present invention provides a method for combining two substrates together, comprising the following steps:

[0045] A step of applying the redox curable composition of the present invention to at least one of the substrates, and a step of forming a bonded assembly by bonding the substrates together for a sufficient time for the redox curable composition to cure.

[0046] Suitably, curing of the redox curable composition is initiated by heating the curable composition and / or exposing the curable composition to pressure. Curing of the redox curable composition may be initiated by exposing the curable composition to an anaerobic environment. Optionally, curing of the redox curable composition is initiated by heating the curable composition in an anaerobic environment and / or exposing the curable composition to pressure.

[0047] The material can be joined using a heating press. The heating press applies a pressure of at least 2 bar, suitably at least 4 bar, to the joined assembly.

[0048] In the method of the present invention, the composition of the present invention may be cured by applying heat and / or pressure to a mated assembly for a period of 30 seconds or more, e.g., 1 minute or more, e.g., 5 minutes or more, or 20 minutes or more. For example, heat and / or pressure is applied to the mated assembly for a period of 1 minute to 20 minutes.

[0049] One or more of the substrates to be bonded may be primed with a primer prior to the application of the redox curable composition of the present invention. Advantageously, the application of the primer facilitates the bonding of a wide variety of substrates using the composition of the present invention. Suitably, the primer may be a thiourea or a thiourethane. Brief explanation of the drawing

[0050] Fig. 1: Presents a DSC temperature record of a solid thermoplastic polyurethane resin to be used in the present invention, having a molecular weight in the range of 40,000 g / mol to 100,000 g / mol. Fig. 2: Presents a DSC temperature record of a solid curable polyurethane (meth)acrylate resin to be used in the present invention, having a molecular weight in the range of about 5,000 g / mol to 35,000 g / mol. Specific details for implementing the invention

[0051] As described above, the present invention provides a redox curable composition, such as an anaerobic curable composition, comprising the following:

[0052] Liquid (meth)acrylate monomer component;

[0053] A solid thermoplastic polyurethane resin having a molecular weight in the range of 40,000 g / mol to 100,000 g / mol and a melting point in the range of 40℃ to 80℃;

[0054] A solid curable polyurethane (meth)acrylate resin having a molecular weight in the range of 5,000 g / mol to 35,000 g / mol and a melting point in the range of 50°C to 80°C; and

[0055] Curing component for curing liquid (meth)acrylate monomer components.

[0056] Definitions and Standard Test Methods

[0057] The term "liquid" means that it is in a liquid state within a temperature range of about 5°C to 30°C, suitably in a liquid state at room temperature and atmospheric pressure.

[0058] The term “solid” means being in a solid state within a temperature range of about 5°C to 40°C, suitably being in a solid state at room temperature and atmospheric pressure. A solid state is defined as a state of matter in which the material is not a fluid and maintains its boundaries without a support, wherein atoms or molecules occupy fixed positions relative to one another and cannot move freely. The pre-coated adhesive composition of the present invention is substantially tack-dry. The composition may be applied to a substrate from a molten state, and on the substrate, they form a tack-dry solid curable composition. Tack-dry is defined as becoming non-fluid at room temperature, becoming non-fluid within a period of 5 minutes or less at room temperature, suitably within a period of about 30 seconds to about 300 seconds at room temperature, suitably within a period of about 30 seconds to 120 seconds at room temperature.

[0059] The molecular weight disclosed herein is determined according to ISO 13885-1:2008 "Binders for paints and varnishes -- Gel permeation chromatography (GPC) -- Part 1: Tetrahydrofuran (THF) as eluent".

[0060] The melting and re-solidification temperature ranges are measured according to ISO 1137-1:2016 "Plastics - Differential scanning calorimetry (DSC) - Part 1 General Principles".

[0061] The liquid (meth)acrylate components are beta-carboxyethyl acrylate, isobornyl acrylate, n-octyl acrylate, n-decyl acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, 2-ethylhexyl acrylate, ethoxyethoxyethyl acrylate, ethoxylated phenyl monoacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, isooctyl acrylate, n-butyl acrylate, neopentyl glycol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, dipropylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, 1,6-hexanediol diacrylate, tripropylene glycol diacrylate, glycerol triacrylate, trimethylolpropane diacrylate, and trimethylolpropane. Triacrylates, pentaerythritol tetraacrylate, phenoxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, cyclohexyl methacrylate, glycerol mono-methacrylate, glycerol 1,3-dimethacrylate, trimethylcyclohexyl methacrylate, methyl triglyceride methacrylate, isobornyl methacrylate, trimethylolpropane trimethacrylate, neopentyl glycol dimethacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, hydroxybutyl methacrylate, tetrahydrofurfuryl methacrylate, cyclohexyl methacrylate, phenoxyethyl methacrylate, glycerol methacrylate, glycidyl methacrylate, methyl methacrylate and methacrylic acid and It may include one or more (meth)acrylate monomers selected from his mixture.

[0062] Preferred liquid (meth)acrylate monomers include 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, tetrahydrofurfuryl methacrylate, isobornyl methacrylate, phenoxyethyl methacrylate, and methacrylic acid.

[0063] The composition may also contain solid (meth)acrylate in the range of about 5% to about 15% based on the total weight of the composition.

[0064] Additionally, one or more suitable (meth)acrylates are polyfunctional (meth)acrylates, e.g., but not limited to, difunctional or trifunctional (meth)acrylates, e.g., polyethylene glycol di(meth)acrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate ("TRIEGMA"), tetraethylene glycol dimethacrylate, dipropylene glycol dimethacrylate, di-(pentamethylene glycol) dimethacrylate, tetraethylene diglycol diacrylate, diglycerol tetramethacrylate, tetramethylene dimethacrylate, ethylene dimethacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, polyethylene glycol di(meth)acrylate, and bisphenol-A mono and di(meth)acrylates, e.g., ethoxylated bisphenol-A (meth)acrylates. ("EBIPMA"), and bisphenol-F mono and di(meth)acrylates, such as ethoxylated bisphenol-F (meth)acrylate, may be selected from.

[0065] For example, the redox curable component may include the following bisphenol A dimethacrylate:

[0066]

[0067] Suitably, the redox curable composition may include ethoxylated bisphenol A di(meth)acrylate.

[0068] Another (meth)acrylate that may be suitable for use in this invention is the silicon (meth)acrylate moiety (“SiMA”) taught and claimed, e.g., by U.S. Patent No. 5,605,999 (Chu), the disclosure of said patent is explicitly incorporated herein by reference.

[0069] Other suitable materials may be selected from polyacrylate esters represented by the following chemical formulas:

[0070]

[0071] Here, R 4 is a radical selected from hydrogen, halogen, or alkyl having 1 to about 4 carbon atoms; q is an integer corresponding to at least 1, preferably 1 to about 4; and X is an organic radical containing at least 2 carbon atoms and having a total bonding ability of q + 1. Regarding the upper limit for the number of carbon atoms of X, monomers are available at essentially all values. However, in practical terms, a general upper limit is about 50, for example, preferably about 30, preferably about 20 carbon atoms.

[0072] For example, X can be an organic radical of the following chemical formula:

[0073]

[0074] Here, Y 1 and Y 2 Each is an organic radical, such as a hydrocarbon group, containing at least two carbon atoms, preferably 2 to about 10 carbon atoms, and Z is an organic radical, preferably a hydrocarbon group, containing at least one carbon atom, preferably 2 to about 10 carbon atoms. Other materials may be selected from the reaction products of di- or tri-alkylolamines (e.g., ethanolamine or propanolamine) and acrylic acid, such as those disclosed in French Patent No. 1,581,361.

[0075] Suitable oligomers having (meth)acrylate functional groups may also be used. Examples of such (meth)acrylate-functionalized oligomers include those having the following chemical formulas:

[0076]

[0077] Here, R 5 is hydrogen, an alkyl having 1 to about 4 carbon atoms, a hydroxyalkyl having 1 to about 4 carbon atoms, or

[0078]

[0079] Represents a radical selected from; where R 4 is a radical selected from hydrogen, a halogen, or an alkyl having 1 to about 4 carbon atoms; R 6 Silver hydrogen, hydroxyl, or

[0080]

[0081] It is a radical selected from; m is an integer corresponding to at least 1, for example, 1 to about 15 or more than that, preferably 1 to about 8; n is an integer corresponding to at least 1, for example, 1 to about 40 or more than that, preferably about 2 to about 10; and p is 0 or 1.

[0082] Typical examples of acrylic acid ester oligomers corresponding to the above chemical formulas 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.

[0083] While difunctional and other polyacrylate esters, particularly the polyacrylate esters described in the previous paragraph, may be preferred, monofunctional acrylate esters (esters containing one acrylate group) may also be used.

[0084] Suitable compounds may be selected from cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, t-butylaminoethyl methacrylate, cyanoethyl acrylate, and chloroethyl methacrylate.

[0085] Another class of useful substances is the reaction product of polyisocyanates with (meth)acrylate-functionalized, hydroxyl- or amino-containing substances in suitable proportions that convert each isocyanate group into a urethane or ureido group.

[0086] The (meth)acrylate urethane or urea ester formed in this way may contain hydroxy or amino functional groups in its non-acrylate portion. Suitable (meth)acrylate esters for use may be selected from those of the following chemical formulas:

[0087]

[0088] Here, X is --O-- and

[0089]

[0090] Selected from; here R 9 is selected from hydrogen or lower alkyls having 1 to 7 carbon atoms; R 7 is selected from hydrogen, halogens (e.g., chlorine), or alkyls (e.g., methyl and ethyl radicals); R 8 It is a divalent organic radical selected from alkylene, phenylene, and naphthylene having 1 to 8 carbon atoms.

[0091] These groups react appropriately with polyisocyanates to produce monomers of the following chemical formula:

[0092]

[0093] Here, n is an integer from 2 to about 6; B is a polyvalent organic radical selected from alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, alkaryl, alkaryl and heterocyclic radicals (both substituted and unsubstituted), and combinations thereof; R 7 , R 8 and X have the meaning given above.

[0094] Depending on the properties of B, these (meth)acrylate esters having urea or urethane links may have a molecular weight that classifies them into the oligomer class (e.g., about 1,000 g / mol to about 5,000 g / mol) or a molecular weight that classifies them into the polymer class (e.g., more than about 5,000 g / mol).

[0095] Other unsaturated reactive monomers and oligomers, such as styrene, maleimide, vinyl ether, allyl, allyl ether, and those mentioned in US6844080B1 (Kneafsey et al.), may be used. Vinyl resins such as those mentioned in US6433091 (Xia) may also be used. Methacrylate or acrylate monomers containing these unsaturated reactive groups may also be used.

[0096] Of course, combinations of these (meth)acrylates and other monomers can also be used.

[0097] Solid-curable polyurethane (meth)acrylate resin

[0098] The solid polyurethane (meth)acrylate resin component for use in the present invention can be produced by reacting a polyol with a diisocyanate to form a polyurethane containing free isocyanato groups, and subsequently reacting the polyurethane containing free isocyanato groups with a hydroxyl-functionalized (meth)acrylate component to form a curable polyurethane (meth)acrylate resin. As described above, the curable polyurethane (meth)acrylate resin used in the present invention is a solid, has a molecular weight in the range of about 5,000 g / mol to about 35,000 g / mol, and has a melting point in the range of about 50°C to about 80°C.

[0099] Suitably, the polyol has a molecular weight in the range of 1,000 to 10,000 g / mol. For example, the polyol may be a reaction product of a polybasic carboxylic acid selected from dibasic to tetrabasic carboxylic acids, such as a polyester polyol, and a polyhydric alcohol selected from divalent, trivalent, tetravalent, or pentavalent alcohols.

[0100] Suitably, the polyol is a polyester polyol having a molecular weight in the range of 1,500 g / mol to about 4,500 g / mol, for example, about 2,000 g / mol to about 4,500 g / mol, for example, about 3,250 g / mol to about 3,750 g / mol.

[0101] Polyester polyols may have a hydroxyl value in the range of 25 to 55, e.g., about 27 to 54, e.g., 27 to 34, when determined according to DIN EN ISO 4629-2.

[0102] Suitably, the polyester polyol has a melting point in the range of 45°C to 75°C, e.g. 55°C to 75°C, preferably 60°C to 75°C, as determined by DSC.

[0103] Polyols may have a viscosity in the range of 0.3 to 2.3 Pa.s at 80°C when determined using the parallel plate method. The method used to determine viscosity above room temperature is based on BS5350 Part B8 "Methods of test for adhesives. Determination of Viscosity".

[0104] The diisocyanate component is suitably an aromatic diisocyanate. For example, the diisocyanate may be selected from toluene diisocyanate, methylene phenyl diisocyanate, and aliphatic diisocyanates selected from isophorone diisocyanate, hexamethylene diisocyanate, and methylene bis(4-cyclohexyl isocyanate).

[0105] The (meth)acrylate component reacting with polyurethane can be selected from acrylic acid, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, methacrylic acid, monoethyl methacrylate phthalate, monoethyl methacrylate maleate, and monoethyl maleate succinate.

[0106] Synthesis of solid polyurethane (meth)acrylate resins

[0107] Examples of starting materials used in the synthesis of solid polyurethane (meth)acrylate resins:

[0108] (a) Polyol:

[0109] (Semi)crystalline polyester polyols, for example, those available from Evonik under the trade name Dynacoll, e.g. Dynacoll 7380, 7381, 7362

[0110] (b) Isocyanate:

[0111] Toluene diisocyanate

[0112] methylene diphenyl isocyanate

[0113] Hydrogenated xylylene diisocyanate

[0114] (c) Capping agent:

[0115] Hydroxyethyl methacrylate

[0116] Glycerol dimethacrylate

[0117] Examples of solid polyurethane (meth)acrylate synthesis:

[0118] Dinacol 7380 (90.89 g), BHT (butylated hydroxytoluene) (0.03 g), MEHQ (4-methoxyphenol) (0.03 g), and phosphoric acid (0.007 g) were added to a reaction vessel and mixed while heating to 120°C. The temperature was allowed to decrease, and mixing was continued at 100°C for 20 minutes. DBTDL (dibutyltin dilaurate) (0.037 g) was added to the mixture, followed by the slow addition of TDI (toluene diisocyanate) (6.28 g) to the reaction mixture, while maintaining the temperature at 100°C throughout the reaction. Mixing was continued for 2–3 hours or until the percentage of isocyanate (NCO) reached equilibrium. A sample of the reaction mixture was titrated to quantify the residual NCO. Based on the titration value, 90 wt% (~2.5 g) of the required HEMA (hydroxyethyl methacrylate) was added to the reaction mixture, followed by the addition of DBTDL (0.037 g). Mixing was continued for 3 hours, and the reaction was monitored for NCO consumption via titration. When equilibrium was reached at a residual % NCO of >0.2% (mol), the remaining 10 wt% of HEMA was added. The reaction was stopped when the NCO content was <0.2% (mol).

[0119] The composition of the present invention comprises a solid thermoplastic polyurethane resin having a molecular weight in the range of 40,000 g / mol to 100,000 g / mol and a melting point in the range of 40°C to 80°C. Suitable solid thermoplastic polyurethane resins include Pearlbond® 100, Pearlbond® 106, Pearlbond® 120, Pearlbond® 122, Pearlbond® 180, Pearlstick® 5712, Pearlstick® 5714 and Pearlstick® 40-70 / 08, which are commercially available from Lubrizol, located at 17 Carre del Gran Vial, Montmelo, Barcelona 08160, Spain.

[0120] primer

[0121] As outlined above, the composition of the present invention may be used in conjunction with a primer. For example, the primer may be used to prime a substrate prior to the application of the composition of the present invention. A commercially available primer sold by Henkel under the trade name Loctite® 7952 is particularly useful. The primer composition comprises, suitably, a thiourea or thiourethane, preferably one or more benzoyl thioureas or benzoyl thiourethanes. Suitable examples of benzoyl thioureas and / or benzoyl thiourethanes are disclosed in U.S. Patent No. 9,371,473 B2, the contents of which are incorporated herein by reference in their entirety, particularly those disclosed in Column 3, line 56 through Column 8, line 10.

[0122] A particularly preferred primer comprises one or more of benzoyl cyclohexyl thiourea, tetramethyl thiourea, tetraethyl thiourea, dimethyl diethyl thiourea, benzoyl thiourea, allyl thiourea, acetyl thiourea, thiourethane, benzoyl octyl thiourea, and benzoyl morphopolynothiourea.

[0123] Examples

[0124] Example 1

[0125]

[0126] The composition of Table 1 was prepared by pre-mixing pellets of HEMA and solid TPU resin (Pearl Bond 100) under high shear. Subsequently, the remaining components (excluding cumene hydroperoxide) were added to the mixture of HEMA and TPU resin under mixing. After the mixture became homogenized, cumene hydroperoxide was added and mixed. Mixing was performed in a sealed container using a Speedmixer™ Model DAX 150.1 FVZ.K. When the container was cooled to room temperature, the adhesive mixture inside solidified.

[0127] The GF-polyarylamide substrate was primed with Loctite® 7952 primer containing 5 wt% of benzoylcyclohexyl thiourea based on the total weight of the primer before applying the composition of Table 1 thereto. The stainless steel substrate was primed with Loctite® 7952 primer containing 0.5 wt% of 2-hydroxyethyl methacrylate phosphate based on the total weight of the primer.

[0128] The application of the adhesive to form a pre-coated adhesive was achieved by heating the composition of Table 1 to 65°C to make it fluid, and then applying the fluid composition to a primed overlapping shear substrate at room temperature, as a result the composition rapidly formed a solid.

[0129] 322.6 mm 2 (0.5 in. 2 A sufficient amount of adhesive composition was applied to the overlapping shear substrate to ensure complete coverage of the bonding area of ​​).

[0130] A pre-coated adhesive composition, 0.5 in 2 The bonding of a glass-filled polyarylamide overlapping shear substrate to a stainless steel overlapping shear substrate was evaluated. Curing was carried out as outlined in Table 2.

[0131]

[0132] Tensile strength was determined according to ISO 4587. Results are presented as the average value from the presented series of test specimens, along with the standard deviation. Unless otherwise noted, assemblies were tested without gap induction (no gap).

[0133] From Table 2, it is evident that there is little difference between the tensile strengths resulting when curing at 65°C is performed for 1 minute or 20 minutes. Therefore, the composition of the present invention can be cured as required.

[0134] Table 3 provides a comparison of tensile strengths for the composition of the present invention and 2K methyl methacrylate structural binder.

[0135]

[0136] Table 3 demonstrates that the pre-coated adhesive of the present invention provides adhesive strength similar to that of commercially available 2K methyl methacrylate adhesives.

[0137] Example 2

[0138]

[0139] The composition of Table 4 was prepared in the same manner as in Example 1 above.

[0140] The pre-coated adhesive composition of Example 2 was evaluated for bonding a glass-filled polyarylamide substrate to another glass-filled polyarylamide substrate with a bonding area of ​​1 / 2 inch. One of the glass-filled polyarylamide substrates was primed with Loctite® 7952 primer containing 5 wt% benzoylcyclohexyl thiourea before applying the composition of Table 4 thereto. The second glass-filled polyarylamide substrate was primed with Loctite® 7952 alone. The first and second substrates were bonded using a heat press at a pressure of 4 bar and a bonding line temperature of 65°C, held for 20 minutes, and then left at room temperature for 30 minutes.

[0141] The bonding strength of the pre-coated adhesive composition of Example 2 in the bonding of two glass-filled polyarylamide substrates was evaluated using no gap and 0.125 mm gap conditions. The bonding strengths are reported in Table 5. Again, the bonding strength (tensile strength) was evaluated according to ISO 4587.

[0142]

[0143] Advantageously, the composition of the present invention can be used to bond passivation substrates, such as plastics. Furthermore, improved adhesive performance was observed in the presence of a gap spacer.

[0144] Example 3

[0145]

[0146] The composition of Example 3 was prepared in the same manner as the compositions of Examples 1 and 2 by pre-mixing pellets of HEMA and solid TPU resin (Pearl Bond 100) under high shear, and subsequently adding the remaining components under mixing. Mixing was performed in a sealed container using a Speedmixer™ Model DAX 150.1 FVZ.K. When the container was cooled to room temperature, the adhesive mixture inside solidified.

[0147] The substrate was primed prior to the application of the pre-coated adhesive. 0.5 in the pre-coated adhesive composition 2 The bonding of a glass-filled polyarylamide substrate to a stainless steel substrate to have a bonding area was evaluated. The glass-filled polyarylamide substrate was previously primed with Loctite® 7952, and the stainless steel substrate was primed with Loctite® 7952 containing 0.5 wt% HEMA phosphate.

[0148] The application of the adhesive composition of Table 6 to form a pre-coated adhesive was achieved by heating the composition to 65°C to make it fluid, and then applying the fluid composition to a primed glass-filled polyarylamide substrate at room temperature, resulting in the composition rapidly solidifying. The pre-coated adhesive and the primed stainless steel substrate on the primed glass-filled polyarylamide substrate were bonded using a heat press at a bonding line temperature of 65°C and a pressure of 4 bar for 20 minutes, followed by 24 hours at room temperature and atmospheric pressure. Subsequently, the tensile strength of the adhesive bond was evaluated according to ISO 4587. The average bond strength of the cured composition of Example 3 for the glass-filled polyarylamide substrate bonded to the SUS304 stainless steel substrate is presented in Table 7.

[0149]

[0150] Example 4

[0151] A thin film of the adhesive composition of Example 1 was prepared by dispensing the molten adhesive composition of Example 1 between two sheets of polyester release liner (Melinex) sandwiched between two heated glass plates. No spacers were used to make the sheets as thin as possible. When dispensing was completed, the glass plates were allowed to cool, and the thin film containing the solidified adhesive composition of Example 1 between the two sheets of Melinex was removed and cut into strips. The tensile strength of the adhesive thin film was evaluated in bonding a primed glass-filled polyarylamide substrate with a primed stainless steel substrate. The glass-filled polyarylamide substrate was primed with Loctite® 7952 containing 5 wt% benzoylcyclohexyl thiourea, and the stainless steel substrate was primed with Loctite® 7952 containing 0.5 wt% HEMA phosphate. A release liner was removed from one side of the adhesive film, and the adhesive film was applied to a primed glass-filled polyarylamide substrate (pressed by hand). Then, a second release liner was removed from the opposite side of the adhesive film, and the adhesive pre-applied on the glass-filled polyarylamide substrate was bonded to a primed stainless steel substrate using a heat press at a bonding line temperature of 65°C and a pressure of 4 bar for 1 minute, followed by 24 hours at room temperature and atmospheric pressure. Subsequently, the tensile strength of the adhesive bond was evaluated according to ISO 4587. The average bond strength of the cured composition of Example 1 for a glass-filled polyarylamide substrate bonded to a SUS304 stainless steel substrate is presented in Table 8.

[0152]

[0153] The words “comprising / including” and “having / accompanying”, when used herein in connection with the present invention, are used to specify the presence of the mentioned feature, integer, step, or component, but do not exclude the presence or addition of one or more other features, integers, steps, components, or groups thereof.

[0154] It is recognized that specific features of the invention described in the context of separate embodiments for clarity may also be provided in combination as a single embodiment. Conversely, various features of the invention described in the context of a single embodiment for brevity may also be provided separately or in any suitable sub-combination.

Claims

Claim 1 A redox curable composition comprising: a liquid (meth)acrylate monomer component; a solid thermoplastic polyurethane resin having a molecular weight in the range of 40,000 g / mol to 100,000 g / mol and a melting point in the range of 40°C to 80°C; a solid curable polyurethane (meth)acrylate resin having a molecular weight in the range of 5,000 g / mol to 35,000 g / mol and a melting point in the range of 50°C to 80°C; and a curing component for curing the liquid (meth)acrylate monomer component. Claim 2 A composition according to claim 1, wherein the liquid (meth)acrylate monomer is present in an amount of 10 wt% to 60 wt% based on the total weight of the curable composition, or in an amount of 25 wt% to 50 wt% based on the total weight of the curable composition. Claim 3 A composition according to claim 1 or 2, wherein the solid thermoplastic polyurethane resin is present in an amount of 5 wt% to 40 wt% based on the total weight of the curable composition, or in an amount of 10 wt% to 30 wt% based on the total weight of the curable composition. Claim 4 A composition according to claim 1 or 2, wherein a solid curable polyurethane (meth)acrylate resin is present in an amount of 20 wt% to 70 wt% based on the total weight of the curable composition, or in an amount of 40 wt% to 60 wt% based on the total weight of the curable composition. Claim 5 A composition according to claim 1 or 2, wherein a curing component for curing a liquid (meth)acrylate monomer component is present in an amount of 0.1 to 10 weight%, 1 to 5 weight%, or 5 weight% based on the total weight of the composition, and / or the curing component comprises a peroxide. Claim 6 A composition according to claim 1 or 2, wherein the liquid (meth)acrylate monomer component is one or more selected from those having the following chemical formula: H2C=CGCO2R 8 ,where G is hydrogen, a halogen, or an alkyl group having 1 to 4 carbon atoms, and R 8 The group is selected from alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkalyl, alkalyl or aryl groups having 1 to 16 carbon atoms, and any of these may optionally be substituted or interposed with silane, silicon, oxygen, halogen, carbonyl, hydroxyl, ester, carboxylic acid, urea, urethane, carbonate, amine, amide, sulfur, sulfonate, sulfone, etc. Claim 7 A composition according to claim 1 or 2, wherein the curing agent is 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, 2-methylindoline, isoindoline, indole, 1,2,3,4-tetrahydroquinoline, 3-methyl-1,2,3,4-tetrahydroquinoline, 2-methyl-1,2,3,4-tetrahydroquinoline, and 1,2,3,4-tetrahydroquinoline-4-carboxylic acid. Claim 8 A composition according to claim 1 or 2, further comprising an initiator for free radical polymerization or a peroxide. Claim 9 In claim 8, the initiator of free radical polymerization is cumene hydroperoxide ("CHP"), para-menthan 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-phosphorus, A composition comprising one or more selected from the group consisting of 4-methyl-2,2-di-t-butylperoxypentane, t-amyl hydroperoxide, 1,2,3,4-tetramethylbutyl hydroperoxide, and combinations thereof. Claim 10 A composition according to claim 8, comprising a peroxide encapsulated with a free radical curing-inducing component. Claim 11 A composition according to claim 1 or 2, further comprising a curing accelerator. Claim 12 A composition according to claim 11, wherein the curing accelerator comprises one or more metallocenes, ferrocenes, or n-butyl ferrocenes. Claim 13 A composition according to claim 1 or 2, wherein the redox curable composition is an anaerobic curable composition. Claim 14 A cured composition formed by curing a curable composition according to claim 1 or 2. Claim 15 In claim 14, a cured composition formed by curing the curable composition by exposing the curable composition to an anaerobic environment. Claim 16 A cured composition according to claim 15, wherein the curable composition is exposed to an anaerobic environment for a period ranging from 1 minute to 30 minutes. Claim 17 A method for combining two substrates together, comprising the following steps: applying a redox curable composition according to claim 1 or 2 to at least one of the substrates; and aligning the substrates together for a sufficient time for the redox curable composition to cure to form a aligned assembly. Claim 18 A method according to claim 17, wherein the curing of the redox curable composition is initiated by heating the curable composition and / or exposing the curable composition to pressure. Claim 19 In paragraph 17, a method in which the material is fitted using a heating press. Claim 20 In paragraph 19, a method in which a heating press applies a pressure of at least 2 bar or at least 4 bar to a mated assembly. Claim 21 A method according to paragraph 17 in which heat and / or pressure is applied to a matched assembly for a period of 30 seconds or more, 1 minute or more, 5 minutes or more, or 20 minutes or more. Claim 22 A method according to paragraph 21 in which heat and / or pressure is applied to a matched assembly for a period of 1 to 20 minutes. Claim 23 A method according to claim 17, wherein one or both of the materials are primed with a primer before the application of the redox curable composition. Claim 24 A method according to claim 23, wherein the primer comprises one or more of thiourea, thiourethane, benzoylcyclohexyl thiourea, tetramethyl thiourea, tetraethyl thiourea, dimethyldiethyl thiourea, benzoyl thiourea, allyl thiourea, acetyl thiourea, thiourethane, benzoyloctyl thiourea, and benzoylmorpholinothiourea. Claim 25 A cured composition according to claim 15, wherein the curing is performed in a temperature range of 40°C to 100°C.

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