WO2022136142A1

WO2022136142A1 - Actinic radiation-curable compositions containing polyamide

Info

Publication number: WO2022136142A1
Application number: PCT/EP2021/086390
Authority: WO
Inventors: Brendan Mcgrail; Noemi FEILLEE
Original assignee: Arkema France
Priority date: 2020-12-21
Filing date: 2021-12-17
Publication date: 2022-06-30
Also published as: TWI804118B; FR3118051A1; TW202231716A

Abstract

Polyamide is combined with one or more actinic radiation-curable compounds to provide compositions, in particular compositions which are liquid at room temperature or which are gels at room temperature but liquids at higher temperatures, which can be cured by exposure to actinic radiation such as UV or visible light to provide articles having improved properties, such as a higher energy at break value, as a result of the inclusion of the polyamide. Such actinic radiation-curable compositions are particularly useful as resins in additive manufacturing processes.

Description

ACTINIC RADIATION-CURABLE COMPOSITIONS CONTAINING POLYAMIDE

Field of the Invention

The invention relates to polyamide-containing compositions capable of being cured using actinic radiation to provide useful articles, including three-dimensional articles prepared using additive manufacturing techniques.

Background of the Related Art

Conventionally, “fused deposition modeling”-type three-dimensional (3D) printing techniques use thermoplastic resins. The use of such resins limits the resolution attainable to the width of a polymer bead that can be laid down. Moreover, articles made using thermoplastic resins and 3D printing methods suffer from poor adhesion between successive printed layers because the mobile polymer chains in the active layer (the layer being printed) cannot re-entangle with the glassy polymer chains in the now-cool previous layer, creating points of mechanical weakness. Photocurable acrylic systems represent another type of resin that has been used for 3D printing of articles, but such systems when cured generally have high crosslink densities. This leads to articles with poor resistance to sudden stresses and strains, resulting in brittle fracture. Consequently, photocurable acrylic resin systems have primarily only found use in prototyping applications.

The development of resin systems for use in 3D printing and other additive manufacturing applications which mitigate the above-mentioned deficiencies of known thermoplastic resin and photocurable acrylic formulations would therefore be of great interest.

U.S. Pat. No. 4,384,011 discloses radiation-curable resin coating compositions containing, in a specific ratio, a soluble polyamide resin and a radiation-polymerizable monomer or the like dissolved in a solvent and the use of such compositions in processes for producing resinous gravure printing plates. The soluble polyamides suitable for such use include polyamides which have been modified by various types of reactions. Moreover, the amount of soluble polyamide resin relative to the amount of radiation-polymerizable monomeric compound is high (100 parts by weight soluble polyamide resin to 50-100 parts by weight radiation-polymerizable monomeric compound). WO 2018/033296 Al discloses polymerization-induced phase-separating (PIPS) compositions for enhancement of impact resistance and rheological properties in photocurable resins for 3D printing, such as for inks, coatings and adhesives. Such compositions are advantageous with respect to properties such as impact resistance, shear adhesion and cohesive strength. The PIPS compositions may include components X, Y and Z, wherein X includes an acrylic-based monomer: Y includes a copolymer of block A and block B: and Z includes a multifunctional cross-linker. Block copolymers which include polyamide blocks are not disclosed.

EP 0919873 B 1 discloses a photocurable resin composition which comprises (A) an acid-modified, vinyl group-containing epoxy resin, (B) an elastomer (which can be a polyamide-based elastomer), (C) a photopolymerization initiator, (D) a diluent and (E) a curing agent and which can give a high performance cured film.

JP 2676662 B2 discloses photosetting films which are made with a low exposure by uniformly dissolving photosensitive aromatic polyamide and a photopolymerization initiator into an organic solvent essentially consisting of a specific polyether compound. The photosensitive polyamide-containing composition is applied on a base material and the coating is dried to form the photosensitive thin film (dry film) containing the photosensitive aromatic polyamide and the photopolymerization initiator. The film is photoset by photoirradiation.

Summary of the Invention

One aspect of the present invention provides an actinic radiation-curable composition comprising: a) at least one polyamide which does not contain actinic radiation-curable functional groups; and b) at least one actinic radiation-curable compound, wherein the at least one actinic radiation- curable compound is a liquid at 25°C; wherein condition i), condition ii) or condition iii) is met: i) the at least one polyamide is an unmodified polyamide or combination of unmodified polyamides and the at least one polyamide is fully solubilized in the actinic radiation-curable composition at 25 °C; ii) at least a portion of the at least one polyamide is present as particles dispersed in the actinic radiation-curable composition at 25 °C; iii) the actinic radiation-curable composition is a gel at 25 °C and a liquid at 100°C or higher.

A method of making a cured polymeric material is also provided by the present invention, wherein the method comprises curing the above-mentioned actinic radiation-curable composition using actinic radiation. A cured polymeric material obtained in accordance with such method is yet another aspect of the invention.

Further provided by the present invention is a method of making a three-dimensional article by additive manufacturing (such as by three-dimensional printing), comprising using the above-mentioned actinic radiation-curable composition to manufacture the three- dimensional article, as well as a three-dimensional article made by such method.

The actinic radiation-curable compositions of the present invention can be in the form of homogeneous solutions of polyamide in liquid matrices comprised of one or more actinic radiation-curable compounds. In other embodiments, at least a portion of the polyamide may be in the form of particles dispersed in a liquid matrix comprised of one or more actinic radiation-curable compounds. The actinic radiation-curable compositions may be rapidly cured using photochemical 3D printing techniques to provide high resolution articles which have improved mechanical characteristics as a consequence of having polyamide present as a component of the composition.

Brief Description of the Drawing

The [Fig 1] is a graph of two Hansen parameters, namely the parameter 3h (in MPa^1/2), which quantifies the energy derived from the intermolecular hydrogen bonds, versus the parameter the parameter 3p (also in MPa^1/2), which represents the energy of the intermolecular dipolar interactions, for a number of compounds which are suitable for use herein as components (a) and (b). Detailed Description of Embodiments of the Invention

Exemplary Characteristics of the Actinic Radiation-Curable Compositions

In accordance with desirable aspects of the present invention (in particular, where the actinic radiation-curable composition is intended for use in a manufacturing process, such as an additive manufacturing process, conducted at ambient temperatures), the actinic radiation- curable composition is formulated so that it is a liquid at 25°C. For example, the actinic radiation-curable composition may be a homogeneous liquid at 25°C. In other embodiments, however, the actinic radiation-curable composition is formulated so that it is a gel at 25°C but a liquid at a higher temperature (e.g., 120°C).

In embodiments where the polyamide or polyamides used in the composition is or are normally solid at 25 °C, the polyamide(s) may be completely solubilized in the other components of the actinic radiation-curable composition. However, according to other aspects of the invention, particles of the at least one polyamide are dispersed in a liquid matrix comprised of the at least one actinic radiation-curable compound. The polyamide component of the composition may be fully or only partially insoluble at 25 °C. For example, according to various embodiments of the invention, 0%, at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90% or 100% by weight of the polyamide component is insoluble at 25°C. In embodiments wherein at least a portion of the polyamide component is in the form of unsolubilized, dispersed particles, such particles may be stably dispersed in the liquid matrix of the at least one actinic radiation-curable compound. The stability of the dispersion may be improved through the use of dispersants and/or modification of the polyamide (for example, by modifying the polyamide to introduce functional groups which assist in stabilizing the dispersed polyamide particles). Generally speaking, it will be advantageous for the particle size of the dispersed polyamide particles to be kept relatively small, for example, d50 values of less than 300 pm, less than 250 pm, or less than 200 pm and/or D90 values of less than 400 pm, less than 350 pm, or less than 300 pm.

According to preferred embodiments of the invention, the actinic radiation-curable composition may have a viscosity at 25°C of not greater than 100,000 mPa.s, not greater than 50,000 mPa.s, not greater than 25,000 mPa.s, not greater than 10,000 mPa.s, or not greater than 5000 mPa.s, as measured using a Brookfield viscometer, model DV-II, using a 27 spindle (with the spindle speed varying typically between 20 and 200 rpm, depending on viscosity). Relatively high viscosities can provide satisfactory performance in applications where the curable composition is heated above 25 °C, such as in three-dimensional printing operations or the like which employ machines having heated resin vats.

Once cured by exposure to an effective amount of actinic radiation (such as ultraviolet or visible light or electron beam radiation), the actinic radiation-curable composition is transformed into a polymeric material. The polymeric material may be clear (transparent), translucent or opaque in appearance. Particles of polyamide in a polymerized matrix derived from the actinic radiation-curable compound(s) which are visible to the unaided human eye may be present. The polyamide may form domains within the polymeric material which are not visible to the unaided human eye. For example, the polymeric material may comprise two phases, one phase being polyamide and another phase being the cured reaction product of the one or more actinic radiation-curable compounds. The polyamide could also be dispersed on a molecular level within the polymeric material. For example, the polymeric material may comprise an interpenetrating polymer network.

Polyamides

The actinic radiation-curable compositions of the present invention contain one or more polyamides. As used herein, the term “polyamide” refers to a polymer in which amide linkages (-C(=O)NH-) occur along the molecular chain (i.e., along the backbone of the polymer). However, as will be explained in more detail subsequently, the polymer backbone may additionally contain one or more other types of linkages besides amide linkages, such as, for example, ether linkages and/or ester linkages. In particular, the compositions comprise at least one polyamide which does not contain any actinic radiation-curable functional groups (i.e., functional groups capable of reacting when exposed to actinic radiation such that the polyamide becomes covalently bound into the polymeric matrix formed by actinic radiation- induced curing of the at least one actinic radiation-curable compound additionally present in the composition, such as (meth)acrylate functional compounds). However, in certain embodiments, the actinic radiation-curable composition may additionally comprise at least one polyamide bearing at least one actinic radiation-curable functional group. According to certain embodiments, the polyamide which does not contain any actinic radiation-curable functional groups (sometimes referred to herein as a “non-functionalized polyamide”) is an aliphatic polyamide. The non-functionalized polyamide may, for example, have a number average molecular weight of at least 5000 g/mol, at least 10,000 g/mol, at least 15,000 g/mol or at least 20,000 g/mol. In other embodiments, the number average molecular weight of the non-functionalized polyamide is no greater than 150,000 g/mol, no greater than 100,000 g/mol, or no greater than 75,000 g/mol. For example, non-functionalized polyamides used in the present invention may have a number average molecular weight of 10,000 to 100,000 g/mol. Gas Permeation Chromatography (GPC) is used herein to measure number average molecular weight Mn following ISO 16014-1:2012. The product is solubilized in hexafluoropropan-2-ol stabilized with 0.05 M of potassium trifluoroacetate and held at 24 hours at ambient temperature at a concentration of 1 g/L. The obtained solution is then filtered on a PTFE membrane (0.2 pm porosity) and injected at a flow rate of 1 mL/min, in a liquid chromatographic system equipped with a set of columns PFG from Polymer Standards Service. The set consists of a pre-column (dimension 50 x 8 mm), a 1000 A column (dimension 300 x 8 mm, particle size 7 pm) and a 100 A column (dimension 300 x 8 mm, particle size 7 pm). The detection is made using refractive index measurement. The measured molecular weights are given in PMMA equivalent (used for calibration).

Polyamides suitable for use in various aspects of the present invention may be modified polyamides. In various other aspects, polyamides which are unmodified polyamides are utilized. It is also possible to employ combinations of one or more unmodified polyamides and one or more modified polyamides. As used herein, the term “modified polyamide” means a polyamide which has been modified by chemical reaction to introduce new functional groups or substituents after being produced in a polymerization reaction. Typically, polymerizations to form polyamides involve condensation reactions in which one or more polyamines is or are reacted with one or more polycarboxylic acids (or equivalents thereof), condensation reactions involving monomers substituted with both amine and carboxylic acid groups, or ring-opening polymerization of a cyclic lactam. Thus, an “unmodified polyamide” is a polyamide which is directly obtained by means of a polymerization reaction and not further reacted in a way that introduces new functional groups or substituents into the polymer. If such an unmodified polyamide is subsequently reacted with one or more reagents in such a manner that a chemical transformation takes place, it is then regarded as a modified polyamide.

In certain embodiments of the invention, the actinic radiation-curable composition is a homogeneous liquid at 25 °C, with the non-functionalized polyamide(s) utilized being completely soluble in the other components of the composition (in particular, completely soluble in the one or more actinic radiation-curable compounds present in the composition). In such embodiments, the polyamide(s) and the actinic radiation-curable compound or mixture of actinic radiation-curable compounds may be selected to have solubility parameters capable of providing the actinic radiation-curable composition in the form of a homogeneous liquid. However, in other embodiments, the polyamide(s) may have only limited solubility at 25 °C in the actinic radiation-curable composition. In still other embodiments, the non-functionalized polyamide(s) is or are insoluble at 25°C in the other components of the actinic radiation- curable composition. In embodiments where the polyamide(s) is or are not fully solubilized, the non-solubilized polyamide(s) or non-solubilized portion thereof may be present in the composition at 25°C in the form of particles, e.g., dispersed particles.

According to certain advantageous embodiments of the invention, the actinic radiation- curable compound or mixture of actinic radiation-curable compounds utilized as component (b) of the actinic radiation-curable composition is selected based on its Hansen solubility parameters, which reflect the physicochemical dissolution properties, also called capacities for solvation, of organic substances. Hansen solubility parameters can be calculated according to the approach proposed by Charles Hansen in the work with the title "Hansen Solubility Parameters: A user's handbook", Second Edition (2007) Boca Raton, Fla.: CRC Press. ISBN 978-O-8493-7248-3. According to this approach, three parameters, called "Hansen parameters": 3d, 8_P, and 8h, are sufficient for predicting the behavior of a solvent with respect to a given molecule. The parameter 3d, in MPa^1/2, quantifies the energy of the forces of dispersion between the molecules, i.e., the van der Waals forces. The parameter 8_P, in MPa^1/2, represents the energy of the intermolecular dipolar interactions. Finally, the parameter 8h, in MPa^1/2, quantifies the energy derived from the intermolecular hydrogen bonds, i.e., the capacity to interact via a hydrogen bond. The sum of the squares of the three parameters corresponds to the square of the Hildebrand solubility parameter (8tot). As is known in the art, the Hansen solubility parameters may be used as a way of predicting if one material will dissolve in another and form a solution. They are based on the idea that “like dissolves like” where one molecule is defined as being “like” another if it bonds to itself in a similar way. The three Hansen solubility parameters may thus be treated as coordinates in a three dimensional (Hansen) space. The closer together two molecules are in this Hansen space, the more likely they may be to form a solution together. The inventors have found that the dispersion parameter 3d, for the non-functionalized polyamide component a) and the actinic radiation curable component b) are similar enough that the Hildebrand solubility parameter for each component is dependent mostly on the parameters 8_P, and 8h and therefore if these are plotted against each other in a two dimensional space, they provide an indication of the solubility of the non-functionalized polyamide component a) in the actinic radiation curable component b).

All of the compounds shown on the attached figure may be suitable for use as components (a) and (b), as appropriate; other compounds (including, for example, other grades of PEB AX® elastomers) not shown on the figure may also be suitable for use as components (a) and (b). Component (a) and component (b), in certain embodiments of the invention, may have a Hansen solubility parameter 8_P from 7 to 10 MPa^1/2 and a Hansen solubility parameter 8h from 4.5 to 8.5 MPa^1/2. According to these embodiments and with reference to the figure, component (a) may be at least one of PEB AX® 2533, polyamide 12 (PA12), PEBAX® 3533, PEB AX® 4033, and PEBAX® 7433, and component (b) may be at least one of SR217, SR420, SR423D, SR506D, SR9075, SR504D, SR567P, SR261, SR789, SR285, SR239EU, and CN1964CG. All of these products are commercially available from the assignee hereof.

In certain embodiments, the actinic radiation-curable composition may be a gel at 25 °C which is capable of being liquefied when heated (e.g., to 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, or 140°C) and/or when combined with a suitable non -reactive solvent or combination of non-reactive solvents. As used herein, the term “gel” may be defined as a colloidal system in which the dispersed phase is liquid and the dispersion medium is solid. A gel may be an immobile semi-solid, in other words it does not flow under its own weight. At 25°C, the gel may be homogeneous, transparent and/or flexible. The actinic radiation-curable composition may be heated to reduce its viscosity for more convenient handling, during a 3D printing operation for example. According to certain embodiments, the actinic radiation-curable composition may be held in a chamber or a vat and heated to a temperature to reduce the viscosity of actinic radiation-curable composition. For example, the actinic radiation-curable composition may be heated to a temperature above the melting point of component a).

According to certain embodiments, the composition comprises at least one thermoplastic polyamide. In other embodiments, the composition comprises at least one polyamide which is a thermoplastic elastomer.

The non-functionalized polyamide may be a linear polyamide, according to various aspects of the invention. However, branched polyamides could also be used. The nonfunctionalized polyamide may have terminal end groups which are carboxylic acid groups, amine groups or both carboxylic acid groups and amine groups. Other types of terminal end groups, other than actinic radiation-curable end groups (e.g., (meth)acrylate end groups), could also or alternatively be present.

Non-functionalized polyamides suitable for use in the present invention include any of the homopolymeric polyamides and copolymeric polyamides known in the art such as, for example, polyamide 6,6, polyamide 6,10, polyamide 10,10, polyamide 6,12, polyamide 4,6, polyamide 6, polyamide 11 and polyamide 12.

Block copolymers comprised of at least one polyamide block are also useful as non- functionalized polyamides in the present invention. Such block copolymers additionally comprise at least one block which is not a polyamide block (sometimes referred to hereinafter as a non-polyamide block), such as, for example, at least one polyester block, at least one polyether-ester block, at least one polyether block, or at least one polyorganosiloxane block. The at least one polyamide block may constitute a “hard” block (e.g., a block having a glass transition temperature (Tg) of 30°C or more), whereas the at least one block other than a polyamide block may constitute a “soft” block (e.g., a block having a Tg of less than 30°C, in particular a block having a Tg of 0°C or less).

Suitable polyamide blocks include blocks of any of the homopolymeric polyamides and copolymeric polyamides known in the art such as, for example, polyamide 6,6, polyamide 6,10, polyamide 10,10, polyamide 6,12, polyamide 4,6, polyamide 6, polyamide 11 and polyamide 12. The number average molecular weight of the polyamide block(s) is not particularly limited and may be varied as may be desired in order to impart certain characteristics to one or both of the actinic radiation-curable composition and the cured product obtained therefrom. For example, the polyamide block or blocks may have a number average molecular weight of at least 400 g/mol or at least 500 g/mol and/or a number average molecular weight of not more than 20,000 g/mol or not more than 10,000 g/mol. According to certain embodiments, the number average molecular weight of the polyamide block(s) may be 400 to 20,000 g/mol or 500 to 10,000 g/mol.

As previously mentioned, the non-polyamide block(s) may, for example, be selected from the group consisting of polyether blocks (blocks containing a plurality of ether linkages in the polymer backbone), polyester blocks (blocks containing a plurality of ester linkages in the polymer backbone, polyether-ester blocks (blocks containing a plurality of both ether and ester linkages in the polymer backbone) and polyorganosiloxane blocks (blocks containing a plurality of -O-Si(R)2- linkages in the polymer backbone, wherein each R is an organic moiety such as a methyl group). Thus, block polymers useful in the present invention include, but are not limited to, polyamide -polyether block copolymers, polyamide-polyester block copolymers, polyamide-polyether-polyester block copolymers, and polyamide -polyorganosiloxane block copolymers.

Suitable polyether blocks include in particular polyoxyalkylene blocks such as blocks formed by ring-opening polymerization of alkylene oxides such as ethylene oxide, propylene oxide, oxetane and tetrahydrofuran. In certain embodiments, the polyoxyalkylene block(s) is or are homopolymeric (i.e., contain repeating units which are identical in structure), but copolymeric blocks comprised of two or more different oxyalkylene repeating units are also possible. Suitable polyether blocks include, but are not limited to, polyethylene glycol blocks (which may also be referred to as polyoxyethylene blocks), polypropylene glycol blocks (which may also be referred to as polyoxypropylene blocks), polytrimethylene glycol blocks (which may also be referred to as polyoxytrimethylene blocks), and polytetramethylene glycol blocks (which may also be referred to as polyoxytetramethylene blocks). The polyether block could also be a block containing a central non-ether moiety, such as a bis-phenol moiety, which is substituted by polyoxyalkylene moieties (such as polyoxyethylene moieties). For example, the polyether block could be an ethoxylated bisphenol A block. One or more polyester blocks could also be present in a polyamide suitable for use in the present invention wherein the polyamide is a block copolymer. Such polyester blocks may be aliphatic polyester blocks, although aromatic polyester blocks could also be used.

In still other embodiments, the non-polyamide block or blocks could be a polyorganosiloxane block, such as a polydimethylsiloxane block.

The number average molecular weight of the non-polyamide block(s) is not particularly limited and may be varied as may be desired in order to impart certain characteristics to one or both of the actinic radiation-curable composition and the cured product obtained therefrom. For example, the non-polyamide block or blocks may have a number average molecular weight of at least 200 g/mol or at least 300 g/mol and/or a number average molecular weight of not more than 6000 g/mol or not more than 3000 g/mol. According to certain embodiments, the number average molecular weight of the non- polyamide block(s) may be 200 to 6000 g/mol or 300 to 3000 g/mol.

The block copolymer comprising at least one polyamide block and at least one non- polyamide block may comprise, for example, from 5 to 95% by weight of polyamide blocks and from 5 to 95% by weight non-polyamide blocks, from 10 to 90% by weight of polyamide blocks and from 10 to 90% by weight non-polyamide blocks, or from 15 to 85% by weight of polyamide blocks and from 15 to 85% by weight non-polyamide blocks, based on the weight of the block copolymer.

In certain embodiments, the polyamide is a block copolymer containing a single non- polyamide block (e.g., a polyether or polyester block) and two polyamide blocks, wherein the non-polyamide block forms a center block and the polyamide blocks form end blocks having the general structure A-B-A wherein A = polyamide block and B = non-polyamide block). However, in other embodiments, the polyamide is a block copolymer containing a single non- polyamide block and a single polyamide block having the general structure A-B wherein A = polyamide block and B = polyether block. In still other embodiments, the non-functionalized polyamide is a multi-block copolymer containing two or more non-polyamide blocks and two or more polyamide blocks arranged in alternating manner and corresponding to the general structure (A-B)_n wherein A = polyamide block, B = non-polyamide block, and n = an integer of 2 or more. Methods of making block copolymers containing one or more polyamide blocks and one or more non-polyamide blocks are well known in the art and any of such methods may be used to prepare polyamide block copolymers for use in the present invention.

Exemplary polyamide block copolymers suitable for use in the present invention are described for example in the following published patent applications, the disclosures of which are incorporated herein by reference in their entirety for all purposes: US 2015/0166746 Al; US 2016/0369098 Al; and US 2016/0251484 Al.

Combinations of two or more different polyamides may be utilized in the present invention. The term “polyamide component” as used herein refers to all the constituents of the actinic radiation-curable composition which are polyamides (whether a single polyamide or a combination of polyamides).

The amount of polyamide component present in the actinic radiation-curable composition may be varied as may be desired or needed in order to achieve properties or characteristics in one or both of the actinic radiation-curable composition or a cured product obtained therefrom following curing by exposure to actinic radiation. For example, the actinic radiation-curable composition may comprise at least 0.5% by weight, at least 1% by weight, at least 2% by weight, at least 5% by weight, or at least 10% by weight of polyamide based on the total weight of the actinic radiation-curable composition. According to certain embodiments, the actinic radiation-curable composition may be comprised of not more than 50% by weight, not more than 40% by weight, or not more than 30% by weight of polyamide based on the total weight of the actinic radiation-curable composition.

In other aspects of the invention, the actinic radiation-curable composition comprises up to 30 parts by weight polyamide per 100 parts by weight actinic radiation-curable compound (where more than one actinic radiation-curable compound is present, per 100 parts by weight of the total amount of actinic radiation-curable compounds). In other aspects, the actinic radiation-curable composition may comprise at least 0.5 parts by weight polyamide per 100 parts by weight actinic radiation-curable compound. For example, in certain embodiments, the actinic radiation-curable composition may comprise 0.5 to 25 parts by weight polyamide per 100 parts by weight actinic radiation-curable compound. In one embodiment, the actinic radiation-curable composition may comprise from 0.5 to 20, from 0.5 to 15, from 0.5 to 10, from 0.5 to 8 or from 0.5 to 6, parts by weight polyamide per 100 parts by weight actinic radiation-curable compound. In another embodiment, the actinic radiation- curable composition may comprise from 5 to 25, from 8 to 25, from 10 to 25 or from 15 to 25, parts by weight polyamide per 100 parts by weight actinic radiation-curable compound.

Actinic Radiation-Curable Compounds

The actinic radiation-curable compositions of the present invention contain, in addition to one or more polyamides, one or more actinic radiation-curable compounds. Such actinic radiation-curable compounds include compounds containing one or more functional groups which are capable of participating in polymerization or curing reactions when exposed to actinic radiation such that a polymeric matrix is formed as a result of covalent bonding involving functional groups on multiple individual molecules of such compounds. Suitable functional groups for such purpose include ethylenically unsaturated functional groups such as (meth)acrylate functional groups (i.e., acrylate functional groups, methacrylate functional groups), (meth)acrylamide functional groups (i.e., acrylamide functional groups, methacrylamide functional groups), cyanoacrylate functional groups, methylidene malonate functional groups, itaconate functional groups, vinyl functional groups, vinyl ether functional groups and the like. An actinic radiation-curable compound used in the present invention may have a single such actinic radiation-curable functional group per molecule or two, three, four or more actinic radiation-curable functional groups per molecule. If the actinic radiation- curable compound contains two or more actinic radiation-curable functional groups per molecule, such functional groups may be the same as or different from each other.

The actinic radiation-curable compounds may be monomeric or oligomeric in character, as described below in more detail. Suitable (meth)acrylate-functionalized compounds, for example, include both (meth)acrylate-functionalized monomers and (meth)acrylate-functionalized oligomers.

According to certain embodiments of the invention, the actinic radiation-curable composition comprises at least one (meth)acrylate-functionalized monomer or oligomer containing two or more (meth)acrylate functional groups per molecule. Examples of useful (meth)acrylate-functionalized monomers containing two or more (meth) acrylate functional groups per molecule include acrylate and methacrylate esters of polyhydric alcohols (organic compounds containing two or more, e.g., 2 to 6, hydroxyl groups per molecule). Specific examples of suitable polyhydric alcohols include C2-20 alkylene glycols (glycols having a C2-10 alkylene group may be preferred, in which the carbon chain may be branched; e.g., ethylene glycol, trimethylene glycol, 1 ,2-propylene glycol, 1,2-butanediol, 1,3 -butanediol, 2,3- butanediol, tetramethylene glycol (1,4-butanediol), 1,5 -pentanediol, 1,6-hexanediol, 1,8- octanediol, 1,9-nonanediol, 1,12-dodecanediol, cyclohexane- 1,4-dimethanol, bisphenols, and hydrogenated bisphenols, as well as alkoxylated (e.g., ethoxylated and/or propoxylated) derivatives thereof, wherein for example from 1 to 20 moles of an alkylene oxide such as ethylene oxide and/or propylene oxide has been reacted with 1 mole of glycol), diethylene glycol, glycerin, alkoxylated glycerin, triethylene glycol, dipropylene glycol, tripropylene glycol, trimethylolpropane, alkoxylated trimethylolpropane, ditrimethylolpropane, alkoxylated ditrimethylolpropane, pentaerythritol, alkoxylated pentaerythritol, dipentaerythritol, alkoxylated dipentaerythritol, cyclohexanediol, alkoxylated cyclohexanediol, cyclohexanedimethanol, alkoxylated cyclohexanedimethanol, norbornene dimethanol, alkoxylated norbornene dimethanol, norbornane dimethanol, alkoxylated norbornane dimethanol, polyols containing an aromatic ring, cyclohexane- 1 ,4-dimethanol ethylene oxide adducts, bis-phenol ethylene oxide adducts, hydrogenated bisphenol ethylene oxide adducts, bisphenol propylene oxide adducts, hydrogenated bisphenol propylene oxide adducts, cyclohexane- 1,4-dimethanol propylene oxide adducts, sugar alcohols and alkoxylated sugar alcohols. Such polyhydric alcohols may be fully or partially esterified (with (meth)acrylic acid, (meth)acrylic anhydride, (meth)acryloyl chloride or the like), provided they contain at least two (meth)acrylate functional groups per molecule. As used herein, the term “alkoxylated” refers to compounds in which one or more epoxides such as ethylene oxide and/or propylene oxide have been reacted with active hydrogen-containing groups (e.g., hydroxyl groups) of a base compound, such as a polyhydric alcohol, to form one or more oxyalkylene moieties. For example, from 1 to 25 moles of epoxide may be reacted per mole of base compound. According to certain aspects of the invention, the (meth)acrylate- functionalized monomer(s) used may be relatively low in molecular weight (e.g., 100 to 1000 g/mol).

Any of the (meth)acrylate-functionalized oligomers known in the art may also be used in the actinic radiation-curable compositions of the present invention. According to certain embodiments, such oligomers contain two or more (meth)acrylate functional groups per molecule. The number average molecular weight of such oligomers may vary widely, e.g., from about 500 to about 50,000.

Suitable (meth)acrylate-functionalized oligomers include, for example, polyester (meth)acrylate oligomers, epoxy (meth)acrylate oligomers, polyether (meth)acrylate oligomers, polyurethane (meth)acrylate oligomers, acrylic (meth)acrylate oligomers, polydiene (meth)acrylate oligomers, polycarbonate (meth)acrylate oligomers, polyamide (meth)acrylate oligomers and combinations thereof. Such oligomers may be selected and used in combination with one or more (meth)acrylate-functionalized monomers in order to adjust or tune the properties of a cured resin prepared using the actinic radiation-curable composition of the present invention.

Exemplary polyester (meth)acrylate oligomers include the reaction products of acrylic or methacrylic acid or mixtures thereof with hydroxyl group-terminated polyester polyols. The reaction process may be conducted such that all or essentially all of the hydroxyl groups of the polyester polyol have been (meth)acrylated, particularly in cases where the polyester polyol is difunctional. The polyester polyols can be made by polycondensation reactions of polyhydroxyl functional components (in particular, diols) and polycarboxylic acid functional compounds (in particular, dicarboxylic acids and anhydrides). The polyhydroxyl functional and polycarboxylic acid functional components can each have linear, branched, cycloaliphatic or aromatic structures and can be used individually or as mixtures.

Examples of suitable epoxy (meth)acrylate oligomers include the reaction products of acrylic or methacrylic acid or mixtures thereof with glycidyl ethers or esters.

Suitable polyether (meth) acrylate oligomers include, but are not limited to, the condensation reaction products of acrylic or methacrylic acid or mixtures thereof with polyetherols which are polyether polyols (such as polyethylene glycol, polypropylene glycol or polytetramethylene glycol). Suitable polyetherols can be linear or branched substances containing ether bonds and terminal hydroxyl groups. Polyetherols can be prepared by ring opening polymerization of cyclic ethers such as tetrahydrofuran or alkylene oxides with a starter molecule. Suitable starter molecules include water, polyhydroxyl functional materials, polyester polyols and amines. Polyurethane (meth)acrylate oligomers (sometimes also referred to as “urethane (meth)acrylate oligomers”) capable of being used in the multi-component systems of the present invention include urethanes based on aliphatic and/or aromatic polyester polyols and polyether polyols and aliphatic and/or aromatic polyester diisocyanates and polyether diisocyanates capped with (meth)acrylate end- groups. Suitable polyurethane (meth)acrylate oligomers include, for example, aliphatic polyester-based urethane di- and tetra-acrylate oligomers, aliphatic polyether-based urethane di- and tetra-acrylate oligomers, as well as aliphatic polyester/polyether-based urethane di- and tetra-acrylate oligomers.

In various embodiments, the polyurethane (meth)acrylate oligomers may be prepared by reacting aliphatic and/or aromatic diisocyanates with OH group terminated polyester polyols (including aromatic, aliphatic and mixed aliphatic/aromatic polyester polyols), polyether polyols, polycarbonate polyols, polycaprolactone polyols, polydimethysiloxane polyols, or polybutadiene polyols, or combinations thereof to form isocyanate-functionalized oligomers which are then reacted with hydroxyl-functionalized (meth)acrylates such as hydroxyethyl acrylate or hydroxyethyl methacrylate to provide terminal (meth)acrylate groups. For example, the polyurethane (meth)acrylate oligomers may contain two, three, four or more (meth)acrylate functional groups per molecule.

Suitable acrylic (meth)acrylate oligomers (sometimes also referred to in the art as “acrylic oligomers”) include oligomers which may be described as substances having an oligomeric acrylic backbone which is functionalized with one or (meth)acrylate groups (which may be at a terminus of the oligomer or pendant to the acrylic backbone). The acrylic backbone may be a homopolymer, random copolymer or block copolymer comprised of repeating units of acrylic monomers. The acrylic monomers may be any monomeric (meth)acrylate such as C1-C6 alkyl (meth)acrylates as well as functionalized (meth)acrylates such as (meth)acrylates bearing hydroxyl, carboxylic acid and/or epoxy groups. Acrylic (meth)acrylate oligomers may be prepared using any procedures known in the art, such as by oligomerizing monomers, at least a portion of which are functionalized with hydroxyl, carboxylic acid and/or epoxy groups (e.g., hydroxyalkyl(meth)acrylates, (meth)acrylic acid, glycidyl (meth)acrylate) to obtain a functionalized oligomer intermediate, which is then reacted with one or more (meth)acrylate-containing reactants to introduce the desired (meth)acrylate functional groups. Exemplary (meth)acrylate-functionalized monomers and oligomers may include ethoxylated bisphenol A di(meth)acrylates; triethylene glycol di(meth)acrylate; ethylene glycol di(meth)acrylate; tetraethylene glycol di(meth)acrylate; polyethylene glycol di(meth)acrylates; 1 ,4-butanediol diacrylate; 1 ,4-butanediol dimethacrylate; diethylene glycol diacrylate; diethylene glycol dimethacrylate, 1,6-hexanediol diacrylate; 1,6-hexanediol dimethacrylate; neopentyl glycol diacrylate; neopentyl glycol di(meth)acrylate; polyethylene glycol (600) dimethacrylate (where 600 refers to the approximate number average molecular weight of the polyethylene glycol portion); polyethylene glycol (200) diacrylate; 1,12- dodecanediol dimethacrylate; tetraethylene glycol diacrylate; triethylene glycol diacrylate, 1,3- butylene glycol dimethacrylate, tripropylene glycol diacrylate, polybutadiene diacrylate; methyl pentanediol diacrylate; polyethylene glycol (400) diacrylate; ethoxylated2 bisphenol A dimethacrylate; ethoxylatedw bisphenol A dimethacrylate; ethoxylateds bisphenol A diacrylate; cyclohexane dimethanol dimethacrylate; cyclohexane dimethanol diacrylate; ethoxylatedw bisphenol A dimethacrylate (where the numeral following “ethoxylated” is the average number of oxyalkylene moieties per molecule); dipropylene glycol diacrylate; ethoxylated4 bisphenol A dimethacrylate; ethoxylatede bisphenol A dimethacrylate; ethoxylated^ bisphenol A dimethacrylate; alkoxylated hexanediol diacrylates; alkoxylated cyclohexane dimethanol diacrylate; dodecanediol diacrylate; ethoxylated4 bisphenol A diacrylate; ethoxylatedw bisphenol A diacrylate; polyethylene glycol (400) dimethacrylate; polypropylene glycol (400) dimethacrylate; metallic diacrylates; modified metallic diacrylates; metallic dimethacrylates; polyethylene glycol (1000) dimethacrylate; methacrylated polybutadiene; propoxylated2 neopentyl glycol diacrylate; ethoxylatedwo bisphenol A dimethacrylate; ethoxylatedso bisphenol A diacrylate; alkoxylated neopentyl glycol diacrylates; polyethylene glycol dimethacrylates; 1,3-butylene glycol diacrylate; ethoxylated2 bisphenol A dimethacrylate; dipropylene glycol diacrylate; ethoxylated4 bisphenol A diacrylate; polyethylene glycol (600) diacrylate; polyethylene glycol (1000) dimethacrylate; tricyclodecane dimethanol diacrylate; propoxylated neopentyl glycol diacrylates such as propoxylated2 neopentyl glycol diacrylate; diacrylates of alkoxylated aliphatic alcohols trimethylolpropane trimethacrylate; trimethylolpropane triacrylate; tris(2-hydroxyethyl) isocyanurate triacrylate; ethoxylated2o trimethylolpropane triacrylate; pentaerythritol triacrylate; ethoxylatedw trimethylolpropane triacrylate; propoxylatedw trimethylolpropane triacrylate; ethoxylatede trimethylolpropane triacrylate; propoxylatede trimethylolpropane triacrylate; ethoxylatedg trimethylolpropane triacrylate; alkoxylated trifunctional acrylate esters; trifunctional methacrylate esters; trifunctional acrylate esters; propoxylateda glyceryl triacrylate; propoxylateds.5 glyceryl triacrylate; ethoxylatedis trimethylolpropane triacrylate; trifunctional phosphoric acid esters; trifunctional acrylic acid esters; pentaerythritol tetraacrylate; di-trimethylolpropane tetraacrylate; ethoxylated4 pentaerythritol tetraacrylate; pentaerythritol polyoxyethylene tetraacrylate; dipentaerythritol pentaacrylate; pentaacrylate esters; epoxy acrylate oligomers; epoxy methacrylate oligomers; urethane acrylate oligomers; urethane methacrylate oligomers; polyester acrylate oligomers; polyester methacrylate oligomers; stearyl methacrylate oligomer; acrylic acrylate oligomers; perfluorinated acrylate oligomers; perfluorinated methacrylate oligomers; amine acrylate oligomers; amine-modified polyether acrylate oligomers; and amine methacrylate oligomers.

The actinic radiation-curable compositions of the present invention may comprise one or more (meth)acrylate-functionalized compounds containing a single acrylate or methacrylate functional group per molecule (referred to herein as “mono(meth)acrylate-functionalized compounds”). Any of such compounds known in the art may be used.

Examples of suitable mono(meth)acrylate-functionalized compounds include, but are not limited to, mono-(meth)acrylate esters of aliphatic alcohols (wherein the aliphatic alcohol may be straight chain, branched or alicyclic and may be a mono-alcohol, a di-alcohol or a polyalcohol, provided only one hydroxyl group is esterified with (meth)acrylic acid); mono- (meth)acrylate esters of aromatic alcohols (such as phenols, including alkylated phenols); mono-(meth)acrylate esters of alkylaryl alcohols (such as benzyl alcohol); mono- (meth)acrylate esters of oligomeric and polymeric glycols such as diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol, and polypropylene glycol); mono-(meth)acrylate esters of monoalkyl ethers of glycols, oligomeric glycols, polymeric glycols; mono-(meth)acrylate esters of alkoxylated (e.g., ethoxylated and/or propoxylated) aliphatic alcohols (wherein the aliphatic alcohol may be straight chain, branched or alicyclic and may be a mono-alcohol, a di-alcohol or a polyalcohol, provided only one hydroxyl group of the alkoxylated aliphatic alcohol is esterified with (meth)acrylic acid); mono-(meth)acrylate esters of alkoxylated (e.g., ethoxylated and/or propoxylated) aromatic alcohols (such as alkoxylated phenols); caprolactone mono(meth)acrylates; and the like. The following compounds are specific examples of mono(meth)acrylate-functionalized compounds suitable for use in the curable compositions of the present invention: methyl (meth)acrylate; ethyl (meth)acrylate; n-propyl (meth)acrylate; n-butyl (meth)acrylate; isobutyl (meth)acrylate; n-hexyl (meth)acrylate; 2-ethylhexyl (meth)acrylate; n-octyl (meth)acrylate; isooctyl (meth)acrylate; n-decyl (meth)acrylate; n-dodecyl (meth)acrylate; tridecyl (meth)acrylate; tetradecyl (meth)acrylate; hexadecyl (meth)acrylate; 2-hydroxyethyl (meth)acrylate; 2- and 3-hydroxypropyl (meth)acrylate; 2-methoxyethyl (meth)acrylate; 2- ethoxyethyl (meth)acrylate; 2- and 3 -ethoxypropyl (meth)acrylate; tetrahydrofurfuryl (meth)acrylate; alkoxylated tetrahydrofurfuryl (meth)acrylate; isobornyl (meth)acrylate; 2-(2- ethoxyethoxy)ethyl (meth)acrylate; cyclohexyl (meth)acrylate; glycidyl (meth)acrylate; isodecyl (meth)acrylate: 2-phenoxyethyl (meth)acrylate: lauryl (meth)acrylate; isobornyl (meth)acrylate; 2-phenoxyethyl (meth)acrylate; alkoxylated phenol (meth)acrylates; alkoxylated nonylphenol (meth)acrylates; cyclic trimethylolpropane formal (meth)acrylate; trimethylcyclohexanol (meth)acrylate; diethylene glycol monomethyl ether (meth)acrylate; diethylene glycol monoethyl ether (meth)acrylate; diethylene glycol monobutyl ether (meth)acrylate; triethylene glycol monoethyl ether (meth)acrylate; ethoxylated lauryl (meth)acrylate; methoxy polyethylene glycol (meth)acrylates; and combinations thereof.

In a preferred embodiment, the at least one actinic radiation-curable compound comprises at least one sterically-hindered (meth)acrylate monomer.

The sterically-hindered (meth)acrylate monomer may have one or two (meth)acrylate groups, preferably one (meth)acrylate group, more preferably one acrylate group. The sterically- hindered (meth)acrylate monomer may comprise a cyclic moiety and/or a tert-butyl group. The cyclic moiety may be monocyclic, bicyclic or tricyclic, including bridged, fused and/or spirocyclic ring systems. The cyclic moiety may be carbocyclic (all of the ring atoms are carbons), or heterocyclic (at least one the rings atoms is a heteroatom such as N, O or S). The cyclic moiety may be aliphatic, aromatic or a combination of aliphatic and aromatic. In particular, the cyclic moiety may comprise a ring or ring system selected from cycloalkyl, heterocycloalkyl, aryl, heteroaryl and combinations thereof. More particularly, the cyclic moiety may comprise a ring or ring system selected from phenyl, cyclopentyl, cyclohexyl, norbornyl, tricyclodecanyl, dicyclopentadienyl, oxiranyl, oxetanyl, tetrahydrofuranyl, tetrahydropyranyl, dioxolanyl, dioxanyl, dioxaspirodecanyl and dioxaspiroundecanyl. The ring or ring system may be optionally substituted by one or more groups selected from hydroxyl, alkoxy, alkyl, hydroxyalkyl, cycloalkyl, aryl, alkylaryl and arylalkyl.

In particular, the cyclic moiety may correspond to one of the following formulae:

wherein the symbol

represents the point of attachment to a moiety comprising a (meth)acrylate functional group, the hashed bond ¹¹ represents a single bond or a double bond; and each ring atom may be optionally substituted by one or more groups selected from hydroxyl, alkoxy, alkyl, hydroxyalkyl, cycloalkyl, aryl, alkylaryl and arylalkyl.

In particular, the sterically hindered (meth)acrylate monomer comprises a cyclic moiety, such as a moiety comprising an aliphatic ring, in particular an aliphatic ring selected from cyclohexane, tricyclodecane, tetrahydrofuran, bornane, 1,3-dioxolane and 1,3-dioxane.

Examples of sterically hindered (meth)acrylate monomers are tert-butyl (meth)acrylate, 2- phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, nonylphenol (meth)acrylate, isobornyl (meth)acrylate, tert-butyl cyclohexyl (meth)acrylate, 3, 3, 5 -trimethyl cyclohexyl (meth)acrylate, dicyclopentadienyl (meth)acrylate, tricyclodecane methanol mono(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, tetrahydrofurfuryl (meth)acrylate, cyclic trimethylolpropane formyl (meth)acrylate (CTFA, also referred to as 5- ethyl- 1 ,3-dioxan-5-yl)methyl (meth)acrylate), (2,2-dimethyl- 1 ,3-dioxolan-4-yl)methyl (meth)acrylate, (2-ethyl-2-methyl-l,3-dioxolan-4-yl)methyl (meth)acrylate, glycerol formal methacrylate, the alkoxylated (i.e. ethoxylated and/or propoxylated) derivatives thereof and mixtures thereof.

In particular, the at least one actinic radiation-curable compound comprises a sterically hindered (meth)acrylate monomer selected from nonylphenol (meth)acrylate, isobornyl (meth)acrylate, tert-butyl cyclohexyl (meth)acrylate, 3, 3, 5 -trimethyl cyclohexyl (meth)acrylate, tricyclodecane methanol mono(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, tetrahydrofurfuryl (meth)acrylate, cyclic trimethylolpropane formyl (meth)acrylate and mixtures thereof.

The sterically-hindered (meth)acrylate monomer may represent at least 10%, from 10 to 90%, from 20 to 85%, from 30 to 80%, from 40 to 75% or from 50 to 70%, by weight of the total weight of the actinic radiation-curable composition.

In a preferred embodiment, the at least one actinic radiation-curable compound comprises at least one acyclic (meth)acrylate monomer.

The acyclic (meth)acrylate monomer may have one or two (meth)acrylate groups, preferably two (meth)acrylate groups. The acyclic (meth)acrylate monomer may be alkoxylated, in particular alkoxylated or propoxylated.

Examples of acyclic (meth)acrylate monomers are lauryl (meth)acrylate, docosyl (meth)acrylate, polyethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,10- decanediol di(meth)acrylate, as well as the alkoxylated (i.e. ethoxylated and/or propoxylated) derivatives thereof and mixtures thereof.

The acyclic (meth)acrylate monomer may represent at least 5%, from 5 to 60%, from 8 to 55%, from 10 to 50%, from 15 to 45% or from 20 to 40%, by weight of the total weight of the curable composition.

In a preferred embodiment, the at least one actinic radiation-curable compound comprises at least one urethane (meth)acrylate.

The urethane (meth)acrylate may have one or two (meth)acrylate groups, preferably two (meth)acrylate groups. The urethane (meth)acrylate may be an aliphatic urethane (meth)acrylate, in particular an aliphatic urethane di(meth)acrylate. The urethane (meth)acrylate monomer may represent at least 10%, from 10 to 90%, from 15 to 85%, from 20 to 80%, from 25 to 75% or from 30 to 70%, by weight of the total weight of the curable composition.

In a particularly preferred embodiment, the at least one actinic radiation-curable compound comprises at least one (meth)acrylate-functionalized monomer and at least one (meth)acrylate- functionalized oligomer; in particular the at least one actinic radiation-curable compound comprises:

- at least one sterically hindered (meth)acrylate monomer, such as nonylphenol (meth)acrylate, isobornyl (meth)acrylate, tert-butyl cyclohexyl (meth)acrylate, 3, 3, 5 -trimethyl cyclohexyl (meth)acrylate, tricyclodecane methanol mono(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, tetrahydrofurfuryl (meth)acrylate, cyclic trimethylolpropane formyl (meth)acrylate and mixtures thereof; and

- at least one urethane (meth)acrylate, such as an aliphatic urethane (meth)acrylate.

The sterically-hindered (meth)acrylate monomer may represent at least 10%, from 10 to 100%, from 15 to 95%, from 20 to 90%, from 25 to 85% or from 30 to 80%, by weight of the total weight of the actinic radiation-curable compounds.

The urethane (meth)acrylate may represent at least 10%, from 10 to 100%, from 15 to 95%, from 20 to 90%, from 25 to 85% or from 30 to 80%, by weight of the total weight of the actinic radiation-curable compounds.

Photoinitiators

In certain embodiments of the invention, the actinic radiation-curable compositions described herein include at least one photoinitiator and are curable with radiant energy (visible light, ultraviolet light). A photoinitiator may be considered any type of substance that, upon exposure to radiation (e.g., actinic radiation), forms species that initiate the reaction and curing of polymerizing organic substances present in the curable composition. Suitable photoinitiators include both free radical photoinitiators as well as cationic photoinitiators and combinations thereof.

Free radical polymerization initiators are substances that form free radicals when irradiated. The use of free radical photoinitiators is especially preferred. Non-limiting types of free radical photoinitiators suitable for use in the curable compositions of the present invention include, for example, benzoins, benzoin ethers, acetophenones, benzyl, benzyl ketals, anthraquinones, phosphine oxides, a-hydroxyketones, phenylglyoxylates, a- aminoketones, benzophenones, thioxanthones, xanthones, acridine derivatives, phenazene derivatives, quinoxaline derivatives and triazine compounds.

If a photoinitiator is present in the actinic radiation-curable curable composition, typical concentrations are up to about 15% by weight based on the total weight of the curable composition. For example, the actinic radiation-curable composition may comprise from 0. 1 to 10% by weight, in total, of photoinitiator, based on the total weight of the curable composition.

Non-Reactive Solvent

According to certain embodiments of the invention, the actinic radiation-curable composition is formulated to be free of, or essentially free of, non-reactive solvent. As used herein, the term “non-reactive solvent” means a solvent which is not capable of being cured by actinic radiation, in contrast to the actinic radiation-curable compound(s) present in the composition. However, the non-reactive solvent could react with one or more components of the composition through other mechanisms.

For example, the actinic radiation-curable composition may comprise less than 5% by weight, less than 2% by weight, less than 1% by weight, less than 0.5% by weight, less than 0.1% by weight or even 0% by weight non-reactive solvent, based on the total weight of the composition.

However, for certain applications, it may be desirable to include a significant amount of one or more non-reactive solvents in the actinic radiation-curable composition. For example, a non-reactive solvent may be utilized to help solubilize one or more components of the composition (in particular, the polyamide component) and/or to reduce the viscosity of the composition. The type of non-reactive solvent that could be used is not limited, provided it does not interfere with the ability to cure the composition by exposing it to actinic radiation. Suitable non-reactive solvents include, for example, ketones (e.g., acetone), esters, ethers, alcohols (including halogenated alcohols, such as fluorinated alcohols, aromatic hydrocarbons, and the like and combinations thereof. The actinic radiation-curable composition could, for example, be formulated to include at least 0.5% by weight, at least 1% by weight, at least 2% by weight, or at least 5% by weight of one or more non-reactive solvents, based on the total weight of the composition. According to other embodiments, the actinic radiation-curable composition comprises up to 90% by weight, up to 80% by weight, up to 70% by weight, up to 60% by weight, up to 50%, by weight, up to 40% by weight, up to 30% by weight, up to 25% by weight or up to 20% by weight of non-reactive solvent(s), based on the total weight of the composition. For example, the actinic radiation-curable composition may comprise 1 to 50% or 1 to 25% by weight non-reactive solvent.

If present, the non-reactive solvent could be either a volatile non-reactive solvent or a non-volatile reactive solvent. As used herein, the term “volatile” means a substance having a boiling point at atmospheric pressure of not more than 100°C and the term “non-volatile” means a substance having a boiling point at atmospheric pressure of greater than 100°C. Combinations of volatile and non-volatile solvents could also be employed.

Also within the scope of the present invention is the use of one or more non-reactive solvents to help solubilize certain components (in particular, the polyamide component) when formulating the composition, wherein after the composition components (including the non- reactive solvent(s)) are combined at least a portion of the non-reactive solvent is then removed to provide the final, formulated actinic radiation-curable composition suitable for use in the desired application (e.g., additive manufacturing). For instance, the components of the composition may be combined and then subjected to processing steps such as mixing and/or heating to achieve a homogenous product or solution, with at least a portion of the non- reactive solvent thereafter being removed by a suitable means such as distillation or vacuum stripping.

Other Optional Additives

Depending upon the particular intended end-use application and the desired properties of the actinic radiation-curable composition and cured product obtained therefrom, one or more other additives may optionally be present in the composition. Such additives may, for example, be selected from the group consisting of chain transfer agents, light blockers (photoblockers), wetting agents (surface tension modifiers), matting agents, colorants, dyes, pigments, adhesion promoters, fillers, rheology modifiers/agents, flow or levelling agents, thixotropic agents, plasticizers, light absorbers, light stabilizing agents, dispersants, antioxidants, antistatic agents, lubricants, opacifying agents, anti-foam agents, polymerization inhibitors, and combinations thereof, including any of the additives conventionally utilized in the coating, sealant, adhesive, molding, 3D printing, additive manufacturing or ink arts.

The actinic radiation-curable compositions of the present invention may comprise one or more light blockers (sometimes referred to in the art as absorbers), particularly where the curable composition is to be used as a resin in a three-dimensional printing method involving photocuring of the curable composition. The light blocker(s) may be any such substances known in the three-dimensional printing art, including for example non-reactive pigments and dyes. The light blocker may be a visible light blocker or a UV light blocker, for example. Examples of suitable light blockers include, but are not limited to, titanium dioxide, carbon black and organic ultraviolet light absorbers such as hydroxybenzophenone, hydroxyphenylbenzotriazole, oxanilide, benzophenone, thioxanthone, hydroxyphenyltriazine, Sudan I, bromothymol blue, 2,2’-(2,5-thiophenediyl)bis(5-tert-butylbenzoxazole) (sold under the brand name “Benetex OB Plus”) and benzotriazole ultraviolet light absorbers.

The amount of light blocker may be varied as may be desired or appropriate for particular applications. Generally speaking, if the actinic radiation-curable composition contains light blocker, it is present in a concentration of from 0.001 to 10 % by weight based on the weight of the curable composition.

Methods of Making

The actinic radiation-curable compositions of the present invention may be prepared by any suitable method. For example, the various desired components may simply be combined and mixed. Where it is desired to achieve a certain level of solubilization of the polyamide component, such solubilization can be facilitated by various means such as, for example, heating the combined components and/or vigorously agitating the combined components. Homogenization methods could also be employed. Additionally, one or more solvents could be utilized to facilitate dissolution of the polyamide component, as previously described. In one embodiment, finely powdered polyamide is added slowly to the other components of the composition at a temperature of 20°C to 90°C while mixing. The resulting actinic radiation-curable composition can then be stored under suitable protective conditions until it is desired to use it to form an article or cured product therefrom.

The inventions also relates a method of making an actinic radiation-curable composition in accordance the invention, wherein the method comprises combining the at least one polyamide, the at least one actinic radiation-curable compound, and at least one volatile solvent capable of solubilizing the at least one polyamide to provide an initial mixture and removing at least a portion of the volatile solvent from the initial mixture to provide the actinic radiation-curable composition.

Uses for the Actinic Radiation-Curable Compositions

As previously mentioned, actinic radiation-curable compositions prepared in accordance with the present invention may contain one or more photoinitiators and may be photocurable. In certain other embodiments of the invention, the actinic radiation-curable compositions described herein do not include any initiator and are curable (at least in part) with electron beam energy.

The actinic radiation-curable compositions described herein may be compositions that are to be subjected to curing by means of free radical polymerization, cationic polymerization or other types of polymerization. In particular embodiments, the curable compositions are photocured (i.e., cured by exposure to actinic radiation such as light, in particular visible, UV, near-UV, infrared and/or near-infrared light).

The invention relates to a method of making a cured product (also referred to as a cured polymeric material) wherein the method comprises curing the actinic radiation-curable composition of the invention. In particular, the actinic radiation-curable composition may be cured by exposing said composition to radiation. More particularly, the actinic radiation- curable composition may be cured by exposing the composition to UV, near-UV, visible, infrared and/or near-infrared radiation or to an electron beam. The cured product obtained with the process of the invention may be an ink, a coating, a sealant, an adhesive, a molded article or a 3D-printed article.

End use applications for the curable compositions include, but are not limited to, inks, coatings, adhesives, additive manufacturing resins (such as 3D printing resins), molding resins, sealants, composites, antistatic layers, electronic applications, recyclable materials, smart materials capable of detecting and responding to stimuli, and biomedical materials.

Advantageously, the cured polymeric material obtained with the actinic radiation- curable composition of the invention has a higher energy at break, as measured by ASTM D256-10 (2018), as compared to a cured polymeric material obtained by photocuring an analogous actinic radiation-curable composition that has the same composition as the actinic radiation-curable composition but does not contain the at least one polyamide.

Accordingly, the present invention relates to a method for increasing the energy at break of a cured polymeric material obtained by photocuring an actinic radiation-curable composition, wherein the method comprises adding at least one polyamide which does not contain actinic radiation-curable functional groups to said actinic radiation-curable composition prior to photocuring. In particular, the radiation-curable composition comprises at least one actinic radiation-curable compound which is a liquid at 25 °C.

The invention also relates to the use of a polyamide which does not contain actinic radiation-curable functional groups to increase the energy at break of a cured polymeric material obtained by photocuring an actinic radiation-curable composition. In particular, the radiation-curable composition comprises at least one actinic radiation-curable compound which is a liquid at 25 °C.

In particular, the cured product may be a 3D-printed article. A 3D-printed article may be defined as an article obtained with a 3D-printer using a computer-aided design (CAD) model or a digital 3D model. The 3D-printed article may, in particular, be obtained with a method of making a 3D-printed article that comprises printing a 3D article with the actinic radiation-curable composition of the invention.

In particular, the method may comprise printing a 3D article layer by layer or continuously. A plurality of layers of the actinic radiation-curable composition in accordance with the present invention may be applied to a substrate surface; the plurality of layers may be simultaneously cured (by exposure to a single dose of radiation, for example) or each layer may be successively cured before application of an additional layer of the actinic radiation- curable composition.The actinic radiation-curable compositions which are described herein can be used as resins in three-dimensional printing applications. The invention thus relates to a method of making a three-dimensional article by additive manufacturing, comprising using the actinic radiation-curable composition of the invention to manufacture the three- dimensional article.

The actinic radiation-curable compositions described herein may be suitable for the process known as hot process 3D printing, where the composition may be extruded in a similar manner to fused filament process 3D manufacturing and either simultaneously or later cured by actinic radiation. Any 3D printing process as described herein may be done at suitable temperature to achieve a desirable viscosity.

Cured compositions prepared from actinic radiation-curable compositions as described herein may be used, for example, in three-dimensional articles (wherein the three-dimensional article may consist essentially of or consist of the cured composition), coated articles (wherein a substrate is coated with one or more layers of the cured composition, including encapsulated articles in which a substrate is completely encased by the cured composition), laminated or adhered articles (wherein a first component of the article is laminated or adhered to a second component by means of the cured composition), composite articles or printed articles (wherein graphics or the like are imprinted on a substrate, such as a paper-, plastic- and/or metalcontaining substrate, using the cured composition).

Curing of the actinic radiation-curable compositions in accordance with the present invention may be carried out by any suitable method, such as free radical and/or cationic polymerization. One or more initiators, such as a free radical initiator (e.g., a photoinitiator which generates free radical species when irradiated) may be present in the actinic radiation- curable composition. Prior to curing, the actinic radiation-curable composition may be applied to a substrate surface in any known conventional manner, for example, by spraying, knife coating, roller coating, casting, drum coating, dipping, and the like and combinations thereof. Indirect application using a transfer process may also be used. Application to a substrate surface may be carried out at ambient (e.g., room) temperature or at an elevated temperature. For example, if the actinic radiation-curable composition is a solid (such as a gel) at ambient temperature, it could be heated to a temperature effective to liquefy the actinic radiation- curable composition to facilitate application to the substrate surface. Such embodiments of the present invention may be utilized, for example, in three-dimensional printing operations or the like which employ machines having heated resin vats or chambers, or in methods where the actinic radiation-curable composition may be extruded and then later cured, or cured during the extrusion step.

A substrate may be any commercially relevant substrate, such as a high surface energy substrate or a low surface energy substrate, such as a metal substrate or plastic substrate, respectively. The substrates may comprise metal, paper, cardboard, glass, thermoplastics such as polyolefins, polycarbonate, acrylonitrile butadiene styrene (ABS), and blends thereof, composites, wood, leather and combinations thereof. When used as an adhesive, the actinic radiation-curable composition may be placed between two substrates and then cured, the cured composition thereby bonding the substrates together to provide an adhered article. Actinic radiation-curable compositions in accordance with the present invention may also be formed or cured in a bulk manner (e.g., the actinic radiation-curable composition may be cast into a suitable mold and then cured).

Curing may be accelerated or facilitated by supplying energy to the actinic radiation- curable composition, such as by exposing the actinic radiation-curable composition to a radiation source, such as visible or UV light, infrared radiation, and/or electron beam radiation. Thus, the cured composition may be deemed the reaction product of the actinic radiation-curable composition, formed by curing. A curable composition may be partially cured by exposure to actinic radiation, with further curing being achieved by heating the partially cured article. For example, an article formed from the curable composition (e.g., a 3D printed article) may be heated at a temperature of from 40°C to 120°C for a period of time of from 5 minutes to 12 hours.

A plurality of layers of an actinic radiation-curable composition in accordance with the present invention may be applied to a substrate surface; the plurality of layers may be simultaneously cured (by exposure to a single dose of radiation, for example) or each layer may be successively cured before application of an additional layer of the actinic radiation- curable composition.

The actinic radiation-curable compositions which are described herein can be used as resins in three-dimensional printing applications. The invention relates to a method of making a three-dimensional article by additive manufacturing, comprising using the actinic radiation-curable composition of the invention to manufacture the three-dimensional article. After the additive manufacturing step, the three- dimensional article may be subjected to a further step of post-curing using at least one of actinic radiation or heat. After the additive manufacturing step, the actinic radiation-cured polymer phase in the three-dimensional article may be removed from the three-dimensional article using at least one of thermal degradation or washing with an organic solvent. After removal of the actinic radiation-cured polymer phase, a polyamide phase may remain in the three-dimensional article and the polyamide phase may thereafter be subjected to thermal sintering.

Three-dimensional (3D) printing (which is a type of additive manufacturing) is a process in which a 3D digital model is manufactured by the accretion of construction material. The 3D printed object is created by utilizing the computer-aided design (CAD) data of an object through sequential construction of two dimensional (2D) layers or slices that correspond to cross-sections of 3D objects. Stereolithography (SL) is one type of additive manufacturing where a liquid resin is hardened by selective exposure to a radiation to form each 2D layer. The radiation can be in the form of electromagnetic waves or an electron beam. The most commonly applied energy source is ultraviolet, visible or infrared radiation.

The inventive actinic radiation-curable compositions described herein may be used as 3D printing resin formulations, that is, compositions intended for use in manufacturing three- dimensional articles using 3D printing techniques. Such three-dimensional articles may be free-standing/self-supporting and may consist essentially of or consist of an actinic radiation- curable composition in accordance with the present invention that has been cured. The three- dimensional article may also be a composite, comprising at least one component consisting essentially of or consisting of a cured composition as previously mentioned as well as at least one additional component comprised of one or more materials other than such a cured composition (for example, a metal component or a thermoplastic component). The actinic radiation-curable compositions of the present invention are particularly useful in digital light printing (DLP), although other types of three-dimensional (3D) printing methods may also be practiced using the inventive curable compositions (e.g., SLA, inkjet). The actinic radiation- curable compositions of the present invention may be used in a three-dimensional printing operation together with another material which functions as a scaffold or support for the article formed from the actinic radiation-curable composition of the present invention.

Thus, the actinic radiation-curable compositions of the present invention are useful in the practice of various types of three-dimensional fabrication or printing techniques, including methods in which construction of a three-dimensional object is performed in a step-wise or layer-by-layer manner. In such methods, layer formation may be performed by solidification (curing) of the actinic radiation-curable composition under the action of exposure to radiation, such as visible, UV or other actinic irradiation. For example, new layers may be formed at the top surface of the growing object or at the bottom surface of the growing object. The actinic radiation-curable compositions of the present invention may also be advantageously employed in methods for the production of three-dimensional objects by additive manufacturing wherein the method is carried out continuously. For example, the object may be produced from a liquid interface. Suitable methods of this type are sometimes referred to in the art as “continuous liquid interface (or interphase) product (or printing)” (“CLIP”) methods. Such methods are described, for example, in WO 2014/126830; WO 2014/126834; WO 2014/126837; and Tumbleston et al., “Continuous Liquid Interface Production of 3D Objects,” Science Vol. 347, Issue 6228, pp. 1349-1352 (March 20, 2015), the entire disclosures of each of which are incorporated herein by reference in their entirety for all purposes.

When stereolithography is conducted above an oxygen-permeable build window, the production of an article using an actinic radiation-curable composition in accordance with the present invention may be enabled in a CLIP procedure by creating an oxygen-containing “dead zone” which is a thin uncured layer of the curable composition between the window and the surface of the cured article as it is being produced. In such a process, an actinic radiation- curable composition is used in which curing (polymerization) is inhibited by the presence of molecular oxygen; such inhibition is typically observed, for example, in curable compositions which are capable of being cured by free radical mechanisms. The dead zone thickness which is desired may be maintained by selecting various control parameters such as photon flux and the optical and curing properties of the curable composition. The CLIP process proceeds by projecting a continuous sequence of actinic radiation (e.g., UV) images (which may be generated by a digital light-processing imaging unit, for example) through an oxygen- permeable, actinic radiation- (e.g., UV-) transparent window below a bath of the actinic radiation-curable composition maintained in liquid form. A liquid interface below the advancing (growing) article is maintained by the dead zone created above the window. The curing article is continuously drawn out of the actinic radiation-curable composition bath above the dead zone, which may be replenished by feeding into the bath additional quantities of the curable composition to compensate for the amounts of actinic radiation-curable composition being cured and incorporated into the growing article.

The invention relates to a method of making a three-dimensional article, comprising: a) applying a first layer of an actinic radiation-curable composition in accordance with the invention onto a surface; b) curing the first layer, at least partially, to provide a cured first layer; c) applying a second layer of the actinic radiation-curable composition onto the cured first layer; d) curing the second layer, at least partially, to provide a cured second layer adhered to the cured first layer; e) repeating steps c) and d) a desired number of times to build up a three-dimensional article comprised of the actinic radiation-curable composition in cured form.

Although the curing steps may be carried out by any suitable means, which will in some cases be dependent upon the components present in the curable composition, in certain embodiments of the invention the curing is accomplished by exposing the layer to be cured to an effective amount of radiation, in particular actinic radiation (e.g., electron beam radiation, UV radiation, visible light, etc.). The three-dimensional article which is formed may be heated in order to effect thermal curing.

Accordingly, in various embodiments, the present invention provides a method of making a three-dimensional article comprising the steps of: a) providing (e.g., coating) a first layer of actinic radiation-curable composition in accordance with the present invention and in liquid form onto a surface; b) exposing the first layer imagewise to actinic radiation to form a first exposed imaged crosssection, wherein the radiation is of sufficient intensity and duration to cause at least partial curing of the layer in the exposed areas; c) providing (e.g., coating) an additional layer of actinic radiation-curable curable composition onto the previously exposed imaged cross-section; d) exposing the additional layer imagewise to actinic radiation to form an additional imaged cross-section, wherein the radiation is of sufficient intensity and duration to cause at least partial curing of the additional layer in the exposed areas and to cause adhesion of the additional layer to the previously exposed imaged cross-section; e) repeating steps c) and d) a desired number of times to build up the three-dimensional article. After the 3D article has been printed, it may be subjected to one or more post-processing steps. The post-processing steps can be selected from one or more of the following steps removal of any printed support structures, washing with water and/or organic solvents to remove residual resins, and post-curing using thermal treatment and/or actinic radiation either simultaneously or sequentially. The post-processing steps may be used to transform the freshly printed article into a finished, functional article ready to be used in its intended application.

In one embodiment, the method of making a three-dimensional article comprises a step of heating the actinic radiation-curable composition above a melting point of component a) at least one polyamide.

The method of making a three-dimensional article may thus comprise the follwogin steps: a') heating an actinic radiation-curable composition in accordance with the invention to a temperature above a melting point of component a); b') applying a first layer of the heated actinic radiation-curable composition onto a surface; c') cooling the first layer to a temperature below the melting point of component a) to afford a cooled first layer; d') curing, at least partially, the cooled first layer to provide a cured first layer; e') applying a second layer of the heated actinic radiation-curable composition onto the cured first layer; f ) cooling the second layer to a temperature below the melting point of component a) to afford a cooled second layer; g') curing, at least partially, the second layer to provide a cured second layer adhered to the cured first layer; h') repeating steps e’), f’), and g’) a desired number of times to build up a three-dimensional article comprised of the actinic radiation-curable composition in cured form. In particular, steps c’) and d’) may be performed at the same time and steps f’) and g’) may be performed at the same time.

The invention also relates to a method of making a three dimensionally printed article using digital light projection, stereolithography or multi jet printing, comprising irradiating an actinic radiation-curable composition in accordance with the invention in a layer by layer manner to form the three dimensionally printed article.

Aspects of the invention

Exemplary aspects of the present invention may be summarized as follows:

Aspect 1 : An actinic radiation-curable composition comprising: a) at least one polyamide which does not contain actinic radiation-curable functional groups; and b) at least one actinic radiation-curable compound, wherein the at least one actinic radiation- curable compound is a liquid at 25°C; wherein condition i), condition ii) or condition iii) is met: i) the at least one polyamide is an unmodified polyamide or combination of unmodified polyamides and the at least one polyamide is fully solubilized in the actinic radiation-curable composition at 25 °C; ii) at least a portion of the at least one polyamide is present as particles dispersed in the actinic radiation-curable composition at 25 °C; iii) the actinic radiation-curable composition is a gel at 25 °C and a liquid at 100°C or higher .

Aspect 2: The actinic radiation-curable composition of Aspect 1, wherein the actinic radiation-curable composition comprises up to 30 parts by weight of polyamide per 100 parts by weight of actinic radiation-curable compound.

Aspect 3 : The actinic radiation-curable composition of either Aspect 1 or Aspect 2, wherein the actinic radiation-curable composition comprises 0.5 to 25 parts by weight of polyamide per 100 parts by weight of actinic radiation-curable compound.

Aspect 4: The actinic radiation-curable composition of any one of Aspects 1 - 3, wherein the actinic radiation-curable composition is a homogeneous liquid at 25°C. Aspect 5: The actinic radiation-curable composition of any one of Aspects 1 - 3, wherein condition iii) is met.

Aspect 6: The actinic radiation-curable composition of any one of Aspects 1 - 3, wherein condition ii) is met and particles of the at least one polyamide are dispersed in a liquid matrix of the at least one actinic radiation-curable compound.

Aspect 7 : The actinic radiation-curable composition of any one of Aspects 1 - 6, wherein the at least one actinic radiation-curable compound comprises at least one actinic radiation-curable compound selected from the group consisting of (meth)acrylate- functionalized compounds, cyanoacrylates, methylidene malonates, itaconates and combinations thereof.

Aspect 8: The actinic radiation-curable composition of any one of Aspects 1 - 7, wherein the at least one actinic radiation-curable compound comprises at least one (meth)acrylate-functionalized oligomer.

Aspect 9: The actinic radiation-curable composition of any one of Aspects 1 - 8, wherein the at least one actinic radiation-curable compound comprises at least one (meth)acrylate-functionalized compound selected from the group consisting of monomeric (meth)acrylates, polyester (meth)acrylate oligomers, polyether (meth)acrylate oligomers, amine (meth)acrylate oligomers, epoxy (meth)acrylate oligomers, urethane (meth)acrylate oligomers and combinations thereof.

Aspect 10: The actinic radiation-curable composition of any one of Aspects 1 - 9, wherein the actinic radiation-curable composition has a viscosity at 25 °C of not greater than 100,000 rnPa.s.

Aspect 11: The actinic radiation-curable composition of any one of Aspects 1 - 10, wherein the at least one polyamide includes at least one polyamide which is a block copolymer comprised of at least one polyamide block and at least one block selected from the group consisting of polyester blocks, polysiloxane blocks, polyether-ester blocks, polyether blocks, and polyorganosiloxane blocks.

Aspect 12. The actinic radiation-curable composition of any one of Aspects 1 - 11, wherein the at least one polyamide includes at least one polyamide which is a block copolymer comprised of at least one polyamide block and at least one block selected from the group consisting of polyethylene glycol blocks, polypropylene glycol blocks, polytetramethylene glycol blocks, polydimethylsiloxane blocks, and ethoxylated bis-phenol A blocks.

Aspect 13: The actinic radiation-curable composition of any one of Aspects 1 - 12, wherein the at least one polyamide block is a polyamide block selected from the group consisting of polyamide 6,6, polyamide 6,10, polyamide 10,10, polyamide 6,12, polyamide 4,6, polyamide 6, polyamide 11 and polyamide 12.

Aspect 14: The actinic radiation-curable composition of any one of Aspects 1 - 13, wherein the at least one polyamide includes at least one polyamide which is a thermoplastic elastomer and which is a block copolymer comprised of at least one polyamide block selected from the group consisting of polyamide 6,6, polyamide 6,10, polyamide 10,10, polyamide 6,12, polyamide 4,6, polyamide 6, polyamide 11 and polyamide 12 and at least one polytetramethylene glycol block.

Aspect 15: The actinic radiation-curable composition of any one of Aspects 1 - 14, wherein the actinic radiation-curable composition is capable of being cured by exposure to at least one of ultraviolet light, visible light, and electron beam radiation.

Aspect 16: The actinic radiation-curable composition of any one of Aspects 1 - 15, wherein the at least one polyamide includes at least one polyamide having a number average molecular weight of from 10,000 to 100,000 g/mol.

Aspect 17: The actinic radiation-curable composition of any one of Aspects 1 - 16, wherein the at least one polyamide includes at least one polyamide selected from the group consisting of polyamide 6,6, polyamide 6,10, polyamide 10,10, polyamide 6,12, polyamide 4,6, polyamide 6, polyamide 11, and polyamide 12.

Aspect 18: The actinic radiation-curable composition of any one of Aspects 1 - 17, additionally comprising at least one photoinitiator.

Aspect 19: The actinic radiation-curable composition of any one of Aspects 1 - 18, wherein the actinic radiation-curable composition comprises less than 0.1 % by weight, based on the weight of the actinic radiation-curable composition, of non-reactive solvent. Aspect 20: The actinic radiation-curable composition of any one of Aspects 1 - 19, wherein the actinic radiation-curable composition is free of non-reactive solvent.

Aspect 21 : The actinic radiation-curable composition of any one of Aspects 1 - 20, wherein condition i) is met and the actinic radiation-curable composition additionally comprises an amount of at least one non-reactive solvent effective to fully solubilize the at least one polyamide in the actinic radiation-curable composition at 25 °C.

Aspect 22: The actinic radiation-curable composition of any one of Aspects 1 - 21 wherein the at least one polyamide is partially dissolved in the at least one actinic radiation- curable compound at 25 °C.

Aspect 23: The actinic radiation-curable composition of any one of Aspects 1 - 22, wherein the at least one polyamide includes at least one polyamide which is a thermoplastic.

Aspect 24: The actinic radiation-curable composition of any one of Aspects 1 - 23, wherein the at least one polyamide includes at least one polyamide which is a thermoplastic elastomer.

Aspect 25: The actinic radiation-curable composition of any one of Aspects 1 - 24, wherein component a) and component b) have Hansen solubility parameter 3p from 7 to 10 MPa^1/2 and Hansen solubility parameter 3h from 4.5 to 8.5 MPa^1/2.

Aspect 26: The actinic radiation-curable composition of any one of Aspects 1 - 25, wherein the actinic radiation-curable composition is selected from the group consisting of adhesives, sealants, coatings, three dimensional printing and additive manufacturing resins, inks and molding resins.

Aspect 27: A method of making a cured polymeric material, wherein the method comprises curing the actinic radiation-curable composition of any one of Aspects 1 to 26 using actinic radiation.

Aspect 28: The method of Aspect 27, wherein the method utilizes at least one of ultraviolet or visible light.

Aspect 29: A cured polymeric material obtained in accordance with the method of either of Aspect 27 or Aspect 28. Aspect 30: The cured polymeric material of Aspect 29, wherein the cured polymeric material has a higher energy at break, as measured by ASTM D256-10 (2018), as compared to a cured polymeric material obtained by photocuring an analogous actinic radiation-curable composition that has the same composition as the actinic radiation-curable composition but does not contain the at least one polyamide.

Aspect 31 : A method of making a three-dimensional article by additive manufacturing, comprising using the actinic radiation-curable composition of any one of Aspects 1 to 26 to manufacture the three-dimensional article.

Aspect 32: The method of Aspect 31, wherein following an additive manufacturing step, the three-dimensional article is subjected to a further step of post-curing using at least one of actinic radiation or heat.

Aspect 33: The method of either Aspect 31 or Aspect 32, wherein following an additive manufacturing step, an actinic radiation-cured polymer phase in the three-dimensional article is removed from the three-dimensional article using at least one of thermal degradation or washing with an organic solvent.

Aspect 34: The method of Aspect 33, wherein following removal of the actinic radiation-cured polymer phase, a polyamide phase remains in the three-dimensional article and the polyamide phase is thereafter subjected to thermal sintering.

Aspect 35: A method of making a three-dimensional article, comprising: a) applying a first layer of an actinic radiation-curable composition in accordance with any one of Aspects 1 to 26 onto a surface; b) curing the first layer to provide a cured first layer; c) applying a second layer of the actinic radiation-curable composition onto the cured first layer; d) curing the second layer to provide a cured second layer adhered to the cured first layer; e) repeating steps c) and d) a desired number of times to build up a three-dimensional article comprised of the actinic radiation-curable composition in cured form. Aspect 36: The method of Aspect 35, wherein the actinic radiation-curable composition is heated above a melting point of the a) at least one polyamide which does not contain actinic radiation-curable functional groups.

Aspect 37: A method of making a three dimensionally printed article using digital light projection, stereolithography or multi jet printing, comprising irradiating an actinic radiation- curable composition in accordance with any one of Aspects 1 to 26 in a layer by layer manner to form the three dimensionally printed article.

Aspect 38: A method of making a three-dimensional article, comprising: a) heating an actinic radiation-curable composition in accordance with any one of Aspects 1 - 26 to a temperature above a melting point of component a); b) applying a first layer of the heated actinic radiation-curable composition onto a surface; c) cooling the first layer to a temperature below the melting point of component a) to afford a cooled first layer; d) curing the cooled first layer to provide a cured first layer; e) applying a second layer of the heated actinic radiation-curable composition onto the cured first layer; f) cooling the second layer to a temperature below the melting point of component a) to afford a cooled second layer; g) curing the second layer to provide a cured second layer adhered to the cured first layer; h) repeating steps e), f), and g) a desired number of times to build up a three-dimensional article comprised of the actinic radiation-curable composition in cured form.

Aspect 39: The method of Aspect 38, wherein steps c) and d) are performed at the same time and steps f) and g) are performed at the same time.

Aspect 40: A method of making an actinic radiation-curable composition in accordance with any one of Aspects 1 - 26, wherein the method comprises combining the at least one polyamide, the at least one actinic radiation-curable compound, and at least one volatile solvent capable of solubilizing the at least one polyamide to provide an initial mixture and removing at least a portion of the volatile solvent from the initial mixture to provide the actinic radiation-curable composition. Within this specification, embodiments have been described in a way which enables a clear and concise specification to be written, but it is intended and will be appreciated that embodiments may be variously combined or separated without departing from the invention. For example, it will be appreciated that all preferred features described herein are applicable to all aspects of the invention described herein.

In some embodiments, the invention herein can be construed as excluding any element or process step that does not materially affect the basic and novel characteristics of the actinic radiation-curable compositions, methods for making the actinic radiation-curable compositions, methods for using the actinic radiation-curable compositions, and articles prepared from the actinic radiation-curable compositions. Additionally, in some embodiments, the invention can be construed as excluding any element or process step not specified herein.

Although the invention is illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the invention.

Examples

Example 1 : Compatibility of polyamides not comprising an actinic radiation-curable functional group (PEBAX® grades 2533 and 4023, Arkema) with mixtures of actinic radiation-curable compounds (SARTOMER® CN1964CG; SR210CG; SR506D, all from Arkema)

These materials are:

SARTOMER® PRO22456: 10 wt % of PEBAX® 2533 in SARTOMER® SR506D

SARTOMER® PRO22457: 10 wt % of PEBAX® 4023 in SARTOMER® SR506D

PRO22456 and PRO22457 were prepared by melting the pellets of Pebax at 110 °C (for PEBAX® 2533) or 120 °C (for PEBAX® 4023) in a kettle. Then the pre-heated monomer SR506D was added while stirring with 1000 ppm of MEHQ and under O2. SARTOMER® SR210CG: Polyethylene Glycol (200) Dimethacrylate (PEG200DMA)

SARTOMER® SR506D: Isobornyl Acrylate (IBOA)

SARTOMER® CN1964CG: urethane dimethacrylate

Tables 1-3 show the mixing conditions and the compatibility results of various combinations of polyamides with actinic radiation-curable compounds. The amounts of polyamide, oligomer and monomer are given in parts by weight. The % of PEBAX in the formulation is expressed as % by weight of PEBAX based on the total weight of the formulation.

[Table 1]

[Table 2]

[Table 3]

The above results show that the addition of the polyamides to the actinic radiation- curable compounds generally provided a liquid or a liquid with small agglomerates immediately after mixing, while hot. However, the mixtures almost always produced a homogeneous gel after cooling for 24 hours at room temperature. Either of these forms is expected to be suitable for use as a medium for additive manufacturing. Example 2: Properties of cured formulations:

This example is based on the dispersion of a PEBAX powder into oligomer or monomer blends. Four different formulations were prepared by combining a powder of polyamide that does not contain an actinic radiation-curable functional group with four different actinic radiation-curable compounds. The amount of polyamide is expressed as a % by weight of polyamide based on the weight of the formulation. All of the preparation and testing was done at room temperature and is detailed below.

Mixing was done using a Glass-Col Rugged Rotator. The samples were cured in silicone molds under an LED Conveyor at full intensity, 395nm wavelength, 50 rpm, and two passes were done for each sample.

Testing was performed as follows:

Viscosity was measured prior to curing using a Brookfield cone and plate rheometer.

The tensile properties after curing were measured using an Instron according to the procedures in ASTM D638. The results and properties after curing are shown in Table 4, with the exception of viscosity, which was measured on the mixtures prior to cure.

[Table 4]

*PEBAX® 9002 from Arkema

These results show that the energy at break improved (was higher than control) for all of the samples incorporating the polyamide. Generally, all of the samples incorporating the polyamide had an increase in opacity. Improved (lower than control) viscosity prior to cure was observed in the mixtures of polyamide with actinic radiation-curable compounds P-220 and 1-150.

Example 3: Properties of 4-tert-butylcvclohexyl acrylate with 17 wt% polyamide compared to 100% 4-tert-butylcyclohexyl acrylate Samples were prepared by first mixing 4-tert-butylcyclohexyl acrylate (TBCHA)

(SARTOMER® SR217, Arkema) with 17 wt% polyamide (PEBAX® 2533, Arkema) based on the weight of the composition. The first step was to melt the pellets of Pebax at 110 °C or 120 °C in a kettle then add the pre-heated monomer SR217 under stirring with 1000 ppm of MEHQ and under O2 in a second step. This preparation was then mixed together at 110 °C with 4 wt% of a photopolymerization initiator (Irgacure® TPO-L, BASF). These were compared to neat 4-tert-butylcyclohexyl acrylate, also in combination with the 4 wt% of the same photopolymerization initiator. The samples were cured under an LED Conveyor at full intensity, 395nm wavelength, and 5 passes on each side at 5 m/min were done for each sample. When post-cured, it was carried out in an oven for 2 hour at 120°C. Their properties were compared using dynamic mechanical analysis (DMA) as well as three-point bending. A cured sample of the blend of 4-tert-butylcyclohexyl acrylate with 17 wt% polyamide was also post-cured with heat and its properties measured with DMA and three point bending. The results are presented in Table 5.

[Table 5]

Claims

46 CLAIMS

1. An actinic radiation-curable composition comprising: a) at least one polyamide which does not contain actinic radiation-curable functional groups; and b) at least one actinic radiation-curable compound, wherein the at least one actinic radiation-curable compound is a liquid at 25°C; wherein condition i), condition ii) or condition iii) is met: i) the at least one polyamide is an unmodified polyamide or combination of unmodified polyamides and the at least one polyamide is fully solubilized in the actinic radiation- curable composition at 25°C; ii) at least a portion of the at least one polyamide is present as particles dispersed in the actinic radiation-curable composition at 25°C; iii) the actinic radiation-curable composition is a gel at 25 °C and a liquid at 100°C or higher.

2. The actinic radiation-curable composition of claim 1 , wherein the actinic radiation-curable composition comprises up to 30 parts, preferably 0.5 to 25 parts, by weight of polyamide per 100 parts by weight of actinic radiation-curable compound.

3. The actinic radiation-curable composition of claim 1 or 2, wherein the actinic radiation- curable composition comprises from 0.5 to 10, from 0.5 to 8 or from 0.5 to 6, parts by weight polyamide per 100 parts by weight actinic radiation-curable compound.

4. The actinic radiation-curable composition of any one of claims 1 to 3, wherein condition iii) is met.

5. The actinic radiation-curable composition of any one of claims 1 to 3, wherein condition ii) is met and particles of the at least one polyamide are dispersed in a liquid matrix of the at least one actinic radiation-curable compound.

6. The actinic radiation-curable composition of any one of claims 1 to 5, wherein the at least one actinic radiation-curable compound comprises at least one actinic radiation-curable compound selected from the group consisting of (meth)acrylate-functionalized compounds, 47 cyanoacrylates, methylidene malonates, itaconates and combinations thereof, preferably at least one (meth)acrylate-functionalized oligomer.

7. The actinic radiation-curable composition of any one of claims 1 to 6, wherein the at least one actinic radiation-curable compound comprises at least one sterically-hindered (meth)acrylate monomer.

8. The actinic radiation-curable composition of claim 7, wherein the sterically hindered (meth)acrylate monomer comprises a cyclic moiety, such as a moiety comprising an aliphatic ring, in particular an aliphatic ring selected from cyclohexane, tricyclodecane, tetrahydrofuran, bornane, 1,3-dioxolane and 1,3-dioxane.

9. The actinic radiation-curable composition of claim 7 or 8, wherein the sterically hindered (meth)acrylate monomer is selected from tert-butyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, nonylphenol (meth)acrylate, isobornyl (meth)acrylate, tert-butyl cyclohexyl (meth)acrylate, 3, 3, 5 -trimethyl cyclohexyl (meth)acrylate, dicyclopentadienyl (meth)acrylate, tricyclodecane methanol mono(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, tetrahydrofurfuryl (meth)acrylate, cyclic trimethylolpropane formyl (meth)acrylate (CTFA, also referred to as 5-ethyl-l,3-dioxan-5- yl)methyl (meth)acrylate), (2,2-dimethyl-l,3-dioxolan-4-yl)methyl (meth)acrylate, (2-ethyl-2- methyl-l,3-dioxolan-4-yl)methyl (meth)acrylate, glycerol formal methacrylate, the alkoxylated derivatives thereof and mixtures thereof.

10. The actinic radiation-curable composition of any one of claims 7 to 9, wherein the sterically-hindered (meth)acrylate monomer represents at least 10%, from 10 to 90%, from 20 to 85%, from 30 to 80%, from 40 to 75% or from 50 to 70%, by weight of the total weight of the actinic radiation-curable composition.

11. The actinic radiation-curable composition of any one of claims 1 to 10, wherein the at least one actinic radiation-curable compound comprises at least one urethane (meth)acrylate.

12. The actinic radiation-curable composition of claim 11, wherein the urethane (meth)acrylate is an aliphatic urethane (meth)acrylate, in particular an aliphatic urethane di(meth)acrylate. 48

13. The actinic radiation-curable composition of claim 11 or 12, wherein the urethane (meth)acrylate monomer represents at least 10%, from 10 to 90%, from 15 to 85%, from 20 to 80%, from 25 to 75% or from 30 to 70%, by weight of the total weight of the curable composition.

14. The actinic radiation-curable composition of any one of claims 1 to 13, wherein the at least one actinic radiation-curable compound comprises at least one (meth)acrylate-functionalized monomer and at least one (meth)acrylate-functionalized oligomer.

15. The actinic radiation-curable composition of any one of claims 1 to 14, wherein the at least one actinic radiation-curable compound comprises:

- at least one sterically hindered (meth)acrylate monomer; and

16. The actinic radiation-curable composition of any one of claims 1 to 15, wherein the at least one polyamide includes at least one polyamide which is a block copolymer comprised of at least one polyamide block and at least one non-polyamide block.

17. The actinic radiation-curable composition of any one of claims 1 to 16, wherein the at least one polyamide includes at least one polyamide which is a block copolymer comprised of at least one polyamide block and at least one block selected from the group consisting of polyester blocks, polysiloxane blocks, polyether-ester blocks, polyether blocks, and polyorganosiloxane blocks.

18. The actinic radiation-curable composition of any one of claims 1 to 17, wherein the at least one polyamide includes at least one polyamide which is a block copolymer comprised of at least one polyamide block and at least one block selected from the group consisting of polyethylene glycol blocks, polypropylene glycol blocks, polytetramethylene glycol blocks, polydimethylsiloxane blocks, and ethoxylated bis-phenol A blocks.

19. The actinic radiation-curable composition of any one of claims 1 to 18, wherein the at least one polyamide includes at least one polyamide selected from the group consisting of polyamide 6,6, polyamide 6,10, polyamide 10,10, polyamide 6,12, polyamide 4,6, polyamide 6, polyamide 11, and polyamide 12.

20. The actinic radiation-curable composition of any one of claims 1 to 19, wherein the actinic radiation-curable composition comprises less than 0.1 % by weight, based on the weight of the actinic radiation-curable composition, of non-reactive solvent and preferably is free of non- reactive solvent.

21. The actinic radiation-curable composition of any one of claims 1 to 20, wherein the at least one polyamide is partially dissolved in the at least one actinic radiation-curable compound at 25°C.

22. A method of making a cured polymeric material, wherein the method comprises curing the actinic radiation-curable composition of any one of claims 1 to 21 using actinic radiation.

23. A cured polymeric material obtained with the method of claim 22.

24. A method of making a three-dimensional article by additive manufacturing, comprising using the actinic radiation-curable composition of any one of claims 1 to 21 to manufacture the three-dimensional article.

25. The method of claim 24, wherein following an additive manufacturing step the three- dimensional article is subjected to a further step of post-curing using at least one of actinic radiation or heat.