Polyoxymethylene-based releasable composition

Abstract

The present invention relates to a curable composition, which comprises at least one curable resin component, and at least one initiator and / or at least one curing agent for polymerizing the curable resin component. In addition, the composition further comprises at least one non-linear polyacetal bridging resin component, which has a large number of acetal functional groups and functional groups of the resin component (A).

Description

Technical Field

[0001] The present invention relates to a curable composition based on polyacetal, which composition is capable of separating and / or dissolving after curing by exposure to water and / or moisture.

[0002] Furthermore, the present invention also relates to a method for separating and / or dissolving joint connections, encapsulations, and coatings made from the composition. Background Art

[0003] In the prior art, various possibilities for separating joint connections are known. In particular for expensive components, the ability to separate or dissolve joint connections is useful to allow post-processing.

[0004] In some applications (such as 3D printing), the fabrication of more complex additive manufacturing structures generally requires support structures. They allow the application of curable compositions, which can then be washed off or separated later. In particular, water-soluble polymers, waxes, or thermoplastic compositions can be used as materials for support structures. The disadvantage of these materials is that the low degree of crosslinking results in unfavorable mechanical properties, especially low cohesion.

[0005] The separation of support structures can be caused by various physical or chemical signals. For example, joint connections can be chemically redissolved by means of solvents, acids, or bases. This is disadvantageous in terms of component and environmental safety as well as workplace safety.

[0006] Alternatively, there are physical methods for separating adhesive joints. For example, a composition having a high content of thermoplastic can be transformed into a state by heating above the glass transition temperature of the composition, in which state the connected components can be separated from the composition by peeling. This method usually leaves residues and fails when used for more complex component geometries.

[0007] From US 6 288 170, a preparation containing epoxy resin is known, which preparation additionally contains thermally expandable microspheres in addition to a curing agent, which microspheres release gas at elevated temperatures, thereby enabling the separation of joints. The fact that a high filling level is required to achieve a high degree of separation is a disadvantage. At the same time, the microspheres exhibit low shear stability, which has a negative impact on the processability of such compositions.

[0008] Adhesive formulations are known from EP 1 914 285 A1, which can be separated from a substrate by applying a voltage. The fact that the formulation needs to have a high ionic liquid content to be redissolvable largely limits the scope of the formulation and is a disadvantage of this method. In addition, the use of a conductive substrate is necessary to redissolve the adhesive.

[0009] WO 2017 / 132497 A1 discloses fluorescent, photo-switchable coumarin-based epoxy resin compositions. By irradiation with a wavelength of less than 300 nm, the polymerized composition can be transformed into a less crosslinked state, in which separation is possible. This method requires specific, commercially unavailable raw materials and only allows a narrow range of formulations. Due to their synthetic route, the required raw materials have a high chlorine content and are therefore not suitable for use in the electronics field. In addition, a radiation-permeable substrate is necessary to separate the composition.

[0010] For example, formulations containing epoxy resins carrying acetal bonds are known from US 5 932 682. The formulation contains an acid anhydride as a curing agent and is intended for encapsulating electronic components. After storage for 1 week under temperature and moisture conditions, a mixture of an acetal-containing epoxide and an alicyclic epoxide without acetal shows only a moderate decrease in the glass transition temperature and does not dissolve. Therefore, the post-processing of the components is very time-consuming and energy-consuming. Organic solvents are necessary to dissolve the composition.

[0011] US 2017 0 298 163 A1 discloses formulations containing an acetal-functionalized crosslinker carrying (meth)acrylate groups. Only linear crosslinkers are described. Generally, the glass transition temperature of the formulation is less than 50 °C and it is intended to be used as a pressure-sensitive adhesive. By using at most bifunctional acetal-based (meth)acrylates, it is not possible to formulate a composition with high resistance and / or glass transition temperature. Therefore, this pressure-sensitive polymer is not suitable for processing in the semiconductor industry.

[0012] From M. Ionescu, S. Sinharoy and Z.S. The scientific publication "Polyacetal Polyols for Polyurethanes", Journal of Polymers and the Environment, 2009, 17, 123 - 130 discloses the structure of hydroxy - functionalized polyacetals as curing agents known for the formation of polyurethanes. The polyacetals are described as biodegradable and / or degradable in the presence of acids. This publication does not describe the synthesis of polyacetals carrying functional groups other than alcohols and capable of being incorporated, for example, into free - radical - polymerizable or cationic - polymerizable compositions. Moreover, no information about the conditions is provided, and the proportion of such compounds in the adhesive composition, which is necessary for achieving the separation of the composition from the substrate, is not specified either. Additionally, due to the amine - based catalysts contained in the composition, the polyacetals obtained by the described synthesis cannot be used to formulate storage - stable compositions.

[0013] US 2019 / 0119534 A1 describes the reaction of vinyl ethers with monovalent carboxylic acids or alcohols to form polyacetals. In this disclosure, thermosoluble compositions can be formulated by adding thermoplastic materials. The softening point of these compositions is above 100 °C; however, they are only thermally cured and have poor adhesion properties. Separation is not intended to be achieved by exposure to moisture.

[0014] The disadvantages of the separable compositions described in the prior art are that they require harsh conditions and / or longer time periods for redissolution, cannot be separated without leaving residues, or contain a large proportion of compounds that are not polymerized into the network of the composition. Summary of the Invention

[0015] An object of the present invention is to overcome the disadvantages of the compositions known in the prior art and to provide curable compositions that, after curing, can be separated or redissolved in an aqueous medium at low temperature without leaving any residues.

[0016] Furthermore, the compositions of the present invention are intended to have a wide range of mechanical properties after curing. In particular, variable glass transition temperatures will be achieved with the said compositions.

[0017] According to the present invention, these objects will be achieved by the curable composition according to claim 1.

[0018] Advantageous embodiments of the composition of the present invention are specified in the dependent claims, which can be optionally combined with each other.

[0019] The present invention further relates to a method for separating and / or dissolving joint connectors, packages, and coatings made from the composition of the present invention.

[0020] Another object of the present invention is the use of the composition of the present invention as an adhesive or a sealant for bonding, encapsulating, sealing or coating a substrate to be separated again.

[0021] The composition of the present invention is particularly suitable for temporary bonding applications.

[0022] The curable composition of the present invention is liquid at room temperature and can be cured by various curing mechanisms (such as actinic radiation and / or heat).

[0023] The composition comprises at least the following components:

[0024] A) at least one curable resin component selected from the group consisting of epoxy-containing compounds, oxetanes, vinyl ethers, (meth)acrylates, and combinations thereof;

[0025] B) at least one initiator and / or at least one curing agent for the polymerization of the curable resin component; and

[0026] C) at least one polyacetal bridging resin component obtainable by reacting at least one at least difunctional vinyl ether (c1) with at least one at least difunctional alcohol (c2) to form a polyacetal intermediate having more than two terminal vinyl ether groups or more than two terminal hydroxyl groups, and

[0027] a) reacting the polyacetal intermediate having more than two terminal vinyl ether groups with at least one mixed-functional compound (c3) having at least one hydroxyl group or at least one amino group, and at least one further resin component (A) functional group or a group capable of polymerizing therewith; or

[0028] b) reacting the polyacetal intermediate having more than two terminal hydroxyl groups with a hydroxyl group-reactive linker and further reacting it with a mixed-functional compound (c3) or an at least difunctional resin component (A); or

[0029] c) reacting the polyacetal intermediate having more than two terminal hydroxyl groups with a mixed-functional compound (c3) having at least one isocyanate group and a further resin component (A) functional group or a group capable of polymerizing therewith.

[0030] Preferably, the composition comprises a resin component (A) having an epoxy-containing compound and / or an oxetane and a curing agent (B1) from the group of amines and / or acid anhydrides.

[0031] Alternatively, the composition may contain an epoxy-containing compound, an oxetane, and / or a vinyl ether as a resin component (A) and an initiator for cationic polymerization.

[0032] According to one embodiment, the composition may contain a free-radically curable (meth)acrylate compound as a resin component (A) and an initiator for free-radical polymerization, either alone or in combination with the resin components and curing agents mentioned above.

[0033] According to another embodiment, the resin component (A) may thus contain an epoxy-containing compound and / or an oxetane and a compound capable of free-radical curing by radiation, or a hybrid compound having an epoxy group and a group capable of free-radical curing by radiation. Further, the composition may contain a curing agent from the group of amines and / or acid anhydrides and additionally contain an initiator for free-radical polymerization.

[0034] The molecular weight of the polyacetal bridging resin component (C) preferably ranges from 2000 g / mol to 20,000 g / mol, more preferably from 2000 g / mol to 8000 g / mol. The molecular weight can be determined according to ISO 16014-2.

[0035] More preferably, based on the total weight of the composition, the polyacetal bridging resin component (C) is present in the composition in a proportion of at least 20 wt%, preferably at least 40 wt%, and particularly preferably at least 50 wt%.

[0036] In addition, the composition may contain a promoter from the group of blowing agents and organic acids, which promotes the separability and solubility of the composition upon exposure to moisture and temperature.

[0037] The present invention also includes a method of forming a joint connector, a package, a support structure, or a coating and redissolving them, the method comprising the following steps:

[0038] Applying the composition of the present invention to a first substrate and optionally bringing the composition into contact with another substrate while forming an adhesive joint;

[0039] Curing the composition by exposure to heat, light, and / or moisture to form a cured joint connector, package, support structure, or coating; and

[0040] Exposing the cured composition to moisture at a predetermined time period and temperature to dissolve and / or separate the composition from the first and optionally the second substrate.

[0041] Another object of the present invention is the use of the composition of the present invention as a temporary support material for additive manufacturing structures. Detailed Description

[0042] Hereinafter, the present invention will be described in detail and by way of examples, however, it should not be construed as restrictive.

[0043] In the context of the present invention, "Liquid" means that the loss modulus G" determined by measuring the viscosity at 23 °C is greater than the storage modulus G' of the composition in question.

[0044] If, after curing, the composition is able to separate from the substrate without leaving any residue when exposed to moisture and temperature, the composition is considered separable.

[0045] If, after curing, the composition completely dissolves when exposed to moisture and temperature, the composition is considered soluble.

[0046] If the indefinite article "a" or "an" is used, it also includes the plural form "one or more", provided that it is not explicitly excluded.

[0047] "At least difunctional" means that each molecule contains more than two of the functional group units mentioned.

[0048] "Of mixed functionality" means that each molecule contains at least two different functional groups.

[0049] Unless otherwise indicated, all parts by weight mentioned hereinafter are based on the total weight of the composition.

[0050] Component (A): Resin

[0051] According to the present invention, the resin component (A) comprises at least one curable, preferably at least difunctional resin component selected from the group consisting of epoxy-containing compounds, oxetanes, vinyl ethers, (meth)acrylates, and combinations thereof.

[0052] Epoxy-containing compound (A1)

[0053] The epoxy-containing compound (A1) in the composition of the present invention preferably comprises one or more at least difunctional epoxy-containing compounds. Here, "at least difunctional" means that the epoxy-containing compound contains at least two epoxy groups. For example, the component (A1) may include alicyclic epoxides, aromatic and aliphatic glycidyl ethers, glycidyl esters or glycidyl amines, and mixtures thereof.

[0054] Bifunctional alicyclic epoxy resins are known in the prior art and include compounds that simultaneously carry alicyclic groups and at least two oxirane rings. Exemplary representatives are 3-cyclohexenylmethyl-3-cyclohexyl carboxylate diepoxide, 3,4-epoxycyclohexylalkyl-3’,4’-epoxycyclohexane carboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-3’,4’-epoxy-6-methylcyclohexane carboxylate, vinylcyclohexene dioxide, bis(3,4-epoxycyclohexylmethyl)adipate, dicyclopentadiene dioxide, and 1,2-epoxy-6-(2,3-epoxypropoxy)hexahydro-4,7-methane indane, and mixtures thereof.

[0055] Aromatic epoxy resins can also be used in the compositions of the present invention. Examples of aromatic epoxy resins are bisphenol-A epoxy resin, bisphenol-F epoxy resin, phenol-novolac epoxy resin, cresol-novolac epoxy resin, biphenyl epoxy resin, 4,4'-biphenyl epoxy resin, divinylbenzenedioxide, 2-glycidylphenyl glycidyl ether, naphthalenediol diglycidyl ether, glycidyl ether of tris(hydroxyphenyl)methane and glycidyl ether of tris(hydroxyphenyl)ethane, and mixtures thereof. In addition, all fully or partially hydrogenated analogues of aromatic epoxy resins can be used.

[0056] Isocyanurates and other heterocyclic compounds substituted by epoxy-containing groups can also be used in the compositions of the present invention. Examples are triglycidyl isocyanurate and monoallyldiglycidyl isocyanurate.

[0057] Furthermore, polyfunctional epoxy resins, viscoplastic epoxy resins and mixtures of various epoxy resins of all the resin groups mentioned can be used in the compositions of the present invention.

[0058] Combinations of several epoxy-containing compounds, at least one of which is bifunctional or has a higher functionality, are also within the scope of the present invention.

[0059] In addition to at least bifunctional epoxy-containing compounds, monofunctional epoxides can also be used as reactive diluents.

[0060] Examples of commercially available epoxy-containing compounds are products available under the following trade names: CELLOXIDE TM 2021P, CELLOXIDE TM8000 (from Daicel Corporation, Japan), EPIKOTE TM RESIN 828 LVEL, EPIKOTE TM RESIN 166, EPIKOTE TM RESIN 169 (from Momentive Specialty Chemicals B.V., Netherlands), Epilox of A, T and AF product series TM Resin (from Leuna Harze, Germany), or EPICLON TM 840, 840-S, 850, 850-S, EXA850CRP, 850-LC (from DIC K.K., Japan), Omnilane 1005 and Omnilane 2005 (from IGM Resins B.V.), Syna Epoxy 21 and Syna Epoxy 06 (from Synasia Inc.), TTA21, TTA26, TTA60 and TTA128 (from Jiangsu Titan New Materials Technology Co., Ltd.).

[0061] Oxetane (A2)

[0062] As an alternative to or in addition to the epoxy-containing compound (A1), it is preferable to use at least a bifunctional oxetane compound (A2) as the cationically curable component (A) in the composition. The method of forming oxetane is particularly known from US 2017 / 0198093 A1.

[0063] Examples of commercially available oxetanes are bis(1-ethyl-3-oxetanyl-methyl)ether (DOX), 3-allyloxymethyl-3-ethyloxetane (AQX), 3-ethyl-3-[(phenoxy)methyl]oxetane (POX), 3-ethyl-3-hydroxymethyloxetane (OXA), 1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene (XDO), 3-ethyl-3-[(2-ethylhexyloxy)methyl]oxetane (EHOX). The oxetanes mentioned are available from TOAGOSEI CO., LTD.

[0064] Vinyl ether (A3):

[0065] As a substitute for compounds (A1) and (A2) or in addition to compounds (A1) and (A2), vinyl ether (A3) can be used as the cationically curable component in the composition of the present invention. It is preferred to use at least bifunctional vinyl ether. Suitable vinyl ethers are trimethylolpropane trivinyl ether, ethylene glycol divinyl ether, triethylene glycol divinyl ether (DVE-3), 1,4-butanediol divinyl ether (BDDVE), 1,4-cyclohexanedimethanol divinyl ether (CHDM-di), 1,2,3-tris(vinyloxy)propane, 1,3,5-tris[(2-vinyloxy)ethoxy]benzene, tris[4-(vinyloxy)butyl] 1,2,4-benzene tricarboxylate, 1,3,5-tris(2-vinyloxyethyl)-1,3,5-triazine, 1,3,5-cyclohexanetrimethanol trivinyl ether, 1,1,1-tris-4-[2-(vinyloxy)ethoxy]phenylethane, tetrakis(vinyloxymethyl)methane and cyclic vinyl ethers and mixtures thereof. In addition, vinyl ethers of polyfunctional alcohols can be used.

[0066] Free-radically curable compound (A4):

[0067] As a substitute for compounds (A1) to (A3) or in addition to compounds (A1) to (A3), a further free-radically curable compound (A4) can be used as the resin component in the composition. No further restrictions are imposed on them in terms of their chemical structure. For example, aliphatic and aromatic (meth)acrylates can be used. Herein and hereinafter, derivatives of acrylic acid and methacrylic acid and their combinations and mixtures are designated as (meth)acrylates. The free-radically curable compound (A4) is preferably radiation curable.

[0068] (Meth)acrylates can be monofunctional or at least difunctional. Preferably, the (meth)acrylate compounds that can be free-radically cured by exposure to heat or radiation are at least difunctional. For example, the following free-radically curable compounds are suitable: isobornyl acrylate, octadecyl acrylate, tetrahydrofurfuryl acrylate, cyclohexyl acrylate, 3,3,5-trimethylcyclohexanol acrylate, docosyl acrylate, 2-methoxyethyl acrylate, and other monofunctional or polyfunctional alkoxylated alkyl acrylates, isobutyl acrylate, isooctyl acrylate, lauryl acrylate, tridecyl acrylate, isooctadecyl acrylate, 2-(o-phenylphenoxy)ethyl acrylate, acryloylmorpholine, N,N-dimethylacrylamide, 4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,10-decanediol diacrylate, tricyclodecane dimethanol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, polybutadiene diacrylate, cyclohexane dimethanol diacrylate, diurethane acrylate of monomeric, oligomeric or polymeric diols and polyols, trimethylolpropane triacrylate (TMPTA) and dipentaerythritol hexaacrylate (DPHA) and combinations thereof. In addition, higher functionality acrylates derived from multi-branched or dendritic alcohols can be advantageously used.

[0069] Similar methacrylates are also within the scope of the present invention.

[0070] Radiation-curable compounds (A4) having allyl groups (e.g., 1,3,5-triazine-2,4,6(1H,3H,5H)trione, which can be obtained commercially) are also suitable. Unhydrogenated polybutadiene having free double bonds (e.g., Poly type) can also be used as the radiation-curable compound (A4). type) can also be used as the radiation-curable compound (A4).

[0071] As higher molecular weight radiation-curable compounds, urethane acrylates based on polyester, polyether, polycarbonate diols and / or (hydrogenated) polybutadiene diols can also be used as component (A4).

[0072] Component (B): Curing agent and / or initiator

[0073] In addition to the curable resin component (A), the composition further contains an initiator and / or a curing agent for the polymerization of component (A). Here, the term "polymerization" is also intended to include the crosslinking of component (A). In terms of their chemical properties, no further restrictions are imposed on the curing agent, and the curing agent includes, for example, one or more of the compounds mentioned below:

[0074] Nitrogen-containing compound (B1)

[0075] For example, a nitrogen-containing compound (B1) can be used as a curing agent (B) for an epoxy-containing compound (A1).

[0076] Examples of suitable nitrogen-containing compounds include amines, especially aliphatic polyamines, arylaliphatic polyamines, cycloaliphatic polyamines, aromatic polyamines, and heterocyclic polyamines, as well as imidazole, cyanamide, polyurea, Mannich base, polyether polyamines, polyaminoamides, phenalkamines, sulfonamides, aminocarboxylic acids, or combinations of the above-mentioned species. Reaction products of epoxides and / or acid anhydrides with the above-mentioned nitrogen-containing compounds can also be used as the curing agent (B).

[0077] Carboxylic anhydride (B2)

[0078] For example, a carboxylic anhydride (B2) can also be used as a curing agent (B) for an epoxy-containing compound (A1).

[0079] Acid anhydrides of diprotic carboxylic acids and aromatic tetrapotic carboxylic acids and mixtures thereof are particularly preferred.

[0080] Specific examples of acid anhydrides that can be used as curing agents in the compositions of the present invention include acid anhydrides of diprotic acids, such as phthalic anhydride (PSA), succinic anhydride, octenyl succinic anhydride (OSA), pentadecenyl succinic acid anhydride, and other alkenyl succinic anhydrides, maleic anhydride (MA), itaconic anhydride (ISA), tetrahydrophthalic anhydride (THPA), hexahydrophthalic anhydride (HHPA), methyltetrahydrophthalic anhydride (MTHPA), methylhexahydrophthalic anhydride (MHHPA), nadic acid anhydride, 3,6-endomethylene tetrahydrophthalic acid anhydride, methylendomethylene tetrahydrophthalic acid anhydride (METH, NMA), tetrabromophthalic acid anhydride, and trimellitic anhydride, as well as acid anhydrides of aromatic tetrabasic acids, such as biphenyltetracarboxylic acid dianhydride, naphthalenetetracarboxylic acid dianhydride, diphenylethertetracarboxylic acid dianhydride, butanetetracarboxylic acid anhydride, cyclopentanetetracarboxylic acid dianhydride, pyromellitic acid anhydride, and benzophenonetetracarboxylic acid dianhydride. These compounds can be used alone or in combination of two or more thereof.

[0081] For example, preferred acid anhydrides used as curing agents (B2) can be commercially obtained under the following trade names. MHHPA: trade names HN-5500 (Hitachi Chemical Co., Ltd.) and MHHPA (Dixie Chemical Company, Inc.), METH: trade name NMA (Dixie Chemical Company, Inc.), METH / ES (Polynt S.p.A) and MHAC (Hitachi Chemical Co., Ltd.).

[0082] Thiol (B3)

[0083] A mercapto group-containing compound (B3) having at least two mercapto groups (-SH) in the molecule can also be used as a curing agent (B) for the epoxy-containing compound (A1).

[0084] In terms of their structure, no further restrictions are imposed on the thiols. Primary or secondary thiols based on aliphatic or aromatic compounds are preferably used. The polythioether acetal disclosed in WO 2019082962A1 is also suitable.

[0085] Preferably, at least bifunctional thiols are selected from the group consisting of ester-based thiols having reactive mercapto groups, polythioethers, polythioether acetals, polythioether thioacetals, polysulfides, thiol-terminated urethanes, thiol derivatives of isocyanurates, and glycoluril and combinations thereof.

[0086] Examples of commercially available ester-based thiols based on 2-mercaptoacetic acid include trimethylolpropane trimercaptoacetate, pentaerythritol tetramercaptoacetate, and glycol dimercaptoacetate, which are available from Bruno Bock under the trade names TM TMPMA, PETMA, and GDMA.

[0087] Further examples of commercially available ester-based thiols include trimethylolpropane-tris(3-mercaptopropionate), pentaerythritol-tetrakis(3-mercaptobutyrate), ethylene glycol-bis(3-mercaptopropionate), and tris[2-(3-mercaptopropionyloxy)ethyl]isocyanurate, which are available from Bruno Bock under the trade name Thiocure TM TMPMP, PETMP, GDMP, and TEMPIC.

[0088] Examples of commercially available thioethers include DMDO (1,8-dimercapto-3,6-dioxaoctane), which is available from Arkema S.A.; DMDS (dimercaptodiethyl sulfide) and DMPT (2,3-di((2-mercaptoethyl)thio)-1-propane-thiol), both of which are available from Bruno Bock.

[0089] Particularly preferred is the use of tris(3-mercaptopropyl) isocyanurate (TMPI) as a trifunctional ester-free thiol in the compositions of the present invention.

[0090] Preferably, based on the total weight of all components, at least difunctional thiols (B3) are present in the compositions of the present invention in a proportion of 10 wt% to 80 wt%, preferably 15 wt% to 70 wt%.

[0091] Photoinitiator for cationic polymerization (B4)

[0092] The compositions of the present invention may contain a photoinitiator (B4) for cationic polymerization. It can be activated by actinic radiation and includes, for example, initiators based on metallocenium and / or onium compounds.

[0093] An overview of various metallocenium salts is disclosed in EP 0 542 716 B1. Examples of various anions of metallocenium salts are HSO4 - , PF6 - , SbF6 - , AsF6 - , Cl - , Br - , I - , ClO4 - , PO4- , SO3CF3 - , OTs - (tosylate), aluminate and borate anions (such as BF4 - and B(C6F5)4 - ).

[0094] Preferably, the photoinitiator based on the metallocene compound is selected from the group of ferrocene salts.

[0095] The preferred onium compounds are selected from the group of arylsulfonium salts and aryl iodonium salts and their combinations, and are described in the prior art.

[0096] The triarylsulfonium-based photoinitiators commercially available as photoacid latent agents can be obtained under the following trade names: Chivacure 1176, Chivacure 1190 (from Chitech), Irgacure290, Irgacure 270, Irgacure GSID 26-1 (from BASF), Speedcure 976 and Speedcure 992 (from Lambson), TTA UV-692, TTA UV-694 (from Jiangsu Titan New Materials Technology Co., Ltd.), or UVI-6976 and UVI-6974 (from Dow Chemical Co.).

[0097] The diaryliodonium-based photoinitiators commercially available as photoacid latent agents are available, for example, under the following trade names: UV1242 or UV2257 (from Deuteron) and Bluesil 2074 (from Bluestar).

[0098] The photoinitiator (C) used in the composition of the present invention can preferably be activated by irradiation with actinic radiation having a wavelength of 200 nm to 480 nm.

[0099] Thermal initiator for cationic polymerization (B5)

[0100] In addition to or in place of the photoinitiator (B4), the composition of the present invention may further contain a thermal initiator for cationic polymerization. For example, the quaternary N-benzylpyridinium salt and N-benzylammonium salt disclosed in EP 0 343 690 or WO 2005 097 883 are suitable as thermal acidifiers. In addition, the thermally latent sulfonium salts described in WO 2019 043 778A1 can be used as acidifiers.

[0101] For example, commercially available products may be obtained under the following names: K-PURE CXC-1614 or K-PURE CXC-1733 (from King Industries Inc.), SAN-AID SI-80L and SAN-AID SI-100L (from SAN-SHIN Chemical Industry Co., Ltd.).

[0102] In addition, various titanium-based or aluminum-based metal chelates can be used as latent heat acids.

[0103] Photoinitiator for free-radical polymerization (B6)

[0104] The composition of the present invention may further contain a photoinitiator (B6) for free radical polymerization.

[0105] As the photoinitiator, common and commercially available compounds can be used, such as α-hydroxy ketones, benzophenones, α,α'-diethoxyacetophenone, 4,4-diethylaminobenzophenone, 2,2-dimethoxy-2-phenylacetophenone, 4-isopropylphenyl-2-hydroxy-2-propylketone, 1-hydroxycyclohexylphenylketone, isoamyl-p-dimethylaminobenzoate, methyl-4-dimethylaminobenzoate, methyl-o-benzoylbenzoate, benzoin, benzoin ethylether, benzoin isopropylether, benzoin isobutylether, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2-isopropylthioxanthone, dibenzosuberone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and bisacylphosphine oxide. The photoinitiators mentioned above can be used alone or in combination of two or more of the mentioned compounds.

[0106] As the UV photoinitiator, for example, IRGACURE from BASF SE can be used TM types, such as IRGACURE 184, IRGACURE 500, IRGACURE 1179, IRGACURE 2959, IRGACURE 745, IRGACURE 651, IRGACURE 369, IRGACURE 907, IRGACURE 1300, IRGACURE 819, IRGACURE 819DW, IRGACURE 2022, IRGACURE 2100, IRGACURE 784, IRGACURE 250, IRGACURE TPO, IRGACURE TPO-L types.

[0107] In addition, those of the type from BASF SE can be used, such as those of the types DAROCUR MBF, DAROCUR 1173, DAROCUR TPO, and DAROCUR 4265.

[0108] The photoinitiators which can be used as component (B5) in the composition of the present invention can preferably be activated by actinic radiation having a wavelength of 200 nm to 400 nm, particularly preferably 250 nm to 365 nm.

[0109] Thermal initiator for free-radical polymerization (B7)

[0110] In particular, peroxides of the perester, diacyl peroxide, peroxy(di)carbonate, and / or hydroperoxide type can be used as thermal initiators in the composition of the present invention. Hydroperoxides are preferably used. Particularly preferred peroxides are cumene hydroperoxide, tert-amyl peroxy-2-ethylhexanoate, and di-(4-tert-butyl-cyclohexyl) peroxydicarbonate.

[0111] The peroxide (B7) is contained in an amount of 0.1 wt% to 10 wt%, preferably 0.5 wt% to 5 wt%, and particularly preferably 1 wt% to 3 wt% based on the total weight of the composition.

[0112] Component (C): Polyacetal-bridged resin component

[0113] In addition to the resin (A), the curing agent and / or the polymerization initiator (B), the composition of the present invention further contains a component (C) comprising at least one polyacetal-bridged resin component. This component is essential in the composition of the present invention and enables the cured composition to separate and / or dissolve in the presence of moisture. At the same time, component (C) enables the cured composition to have a wide mechanical range and enables it to avoid, for example, the disadvantages regarding the cohesion of the cured composition and / or the high viscosity of the liquid curable composition.

[0114] According to the present invention, the component (C) is a non-linear polyacetal bridging resin component, which can be obtained by: reacting at least one at least difunctional vinyl ether (c1) with at least one at least difunctional alcohol (c2) to form a polyacetal intermediate having more than two terminal vinyl ether groups or more than two terminal hydroxyl groups, and

[0115] (a) reacting the polyacetal intermediate having more than two terminal vinyl ether groups with at least one mixed-functional compound (c3), the mixed-functional compound (c3) having at least one hydroxyl group or at least one amino group, and at least one further resin component (A) functional group or a group capable of polymerizing therewith; or

[0116] (b) reacting the polyacetal intermediate having more than two terminal hydroxyl groups with an optionally at least difunctional hydroxyl group-reactive linker (e.g., a linker selected from the group consisting of carboxylic anhydrides, at least difunctional carboxylic anhydrides, and at least difunctional isocyanates), and further reacting it with a mixed-functional compound (c3) or a difunctional resin component (A); or

[0117] (c) reacting the polyacetal intermediate having more than two terminal hydroxyl groups with a mixed-functional compound (c3), the mixed-functional compound (c3) having at least one isocyanate group and a further resin component (A) functional group or a group capable of polymerizing therewith.

[0118] For example, if an epoxy resin or an oxetane resin is used as the resin component (A), the component (C) also has epoxy groups and / or oxetane groups. If the resin component (A) contains a radiation-curable (meth)acrylate group, the component (C) can also have such a (meth)acrylate group. If a vinyl ether-based resin component (A) is used, a component (C) containing a vinyl ether group or other cationically polymerizable group (e.g., an epoxy group or an oxetane group) can be used. Thus, the component (C) is compatible with the resin component (A) present in the curable composition and is reactively incorporated into the resin matrix under polymerization conditions. The large number of polyacetal functional groups in the component (C) resulting from the use of a non-linear polyacetal intermediate having more than two terminal vinyl ether groups or other reactive terminal groups ensures that the cured composition can be rapidly separated or dissolved.

[0119] Advantageously, the reaction of the at least difunctional vinyl ether (c1) with the at least difunctional alcohol (c2) and at least one mixed-functional compound (c3) to form the component (C) can be carried out as a one-step synthesis.

[0120] It is also within the scope of the present invention to use polyacetal bridging resin components (C) having several different structures, provided that a mixed-functional component (c3) is selected such that the polyacetal bridging resin component (C) is capable of having functional groups that form a resin matrix with at least one of the resins (A) used.

[0121] By additionally using mixed-functional compounds (c3) that are different from each other, hybrid compounds can be obtained. For example, a polyacetal bridging resin component (C) having (meth)acrylate end groups and epoxy and / or oxetane end groups and capable of reacting in both free radical polymerization and cationic polymerization reactions can be obtained by using a mixture of a hydroxy-functional (meth)acrylate and a hydroxy-functional oxetane and / or epoxide as component (c3). For example, such a polyacetal bridging resin component (C) can be used in an epoxy acrylate hybrid formulation.

[0122] It is not preferred to use a compound (c3) that does not have any of the following groups: a group corresponding to the resin used in component (A), or a group that can polymerize with the resin used in component (A). Such polyacetal compounds prevent the formulation of the compositions of the present invention because they cannot copolymerize with the curable compositions, thus resulting in poor adhesion properties in the cured compositions.

[0123] The formation of a branched polyacetal intermediate having more than two terminal vinyl ether groups or hydroxy groups is achieved by having at least one of compounds (c1) or (c2) be trifunctional or have a higher functionality. If only bifunctional vinyl ether (c1) and bifunctional alcohol (c2) react with each other, only a linear polyacetal compound can be formed, resulting in compositions having a low glass transition temperature and a low network density, which are not within the scope of the present invention.

[0124] The molar mass range of the polyacetal bridging compound (C) can be from 2000 g / mol to 20,000 g / mol, preferably from 2000 g / mol to 8000 g / mol.

[0125] It is also within the scope of the present invention to use polyacetal compounds (C) having several different structures provided that at least one of compounds (c1) or (c2) is trifunctional or has a higher functionality.

[0126] Hereinafter, compounds c1, c2, and c3 for forming a mixed-functional polyacetal bridging compound (C) will be described in detail:

[0127] Compound (c1): At least bifunctional vinyl ether

[0128] As the compound (c1), aliphatic, alicyclic and aromatic vinyl ethers can be used. Preferably, polar difunctional, trifunctional and tetrafunctional vinyl ethers are used, preferably difunctional and trifunctional vinyl ethers, such as diethylene glycol divinyl ether (DVE-2), triethylene glycol divinyl ether (DVE-3), 1,4-butanediol divinyl ether (BDDVE), 1,4-cyclohexanedimethanol divinyl ether (CHDM-di), 1,2,3-tris(vinyl-oxy)propane, trimethylolpropane trivinyl ether, 1,3,5-tris[(2-vinyl-oxy)ethoxy]benzene, 1,2,4-benzenetricarboxylic acid tris[4-(vinyl-oxy)butyl]ester, 1,3,5-tris(2-vinyl-oxyethyl)-1,3,5-triazine, 1,3,5-cyclohexanetri-methanol trivinyl ether, 1,1,1-tris-4-[2-(vinyl-oxy)ethoxy]phenyl-ethane, tetra(vinyl-oxymethyl)methane.

[0129] Compound (c2): At least bifunctional alcohol

[0130] As the compound (c2), difunctional or polyfunctional primary and secondary aliphatic, alicyclic and aromatic alcohols can be used. Preferably, difunctional, trifunctional, tetrafunctional and pentafunctional alcohols are used, particularly preferably trifunctional and tetrafunctional alcohols. Suitable alcohols include 1,3-propanediol, 1,4-butanediol, 2,3-butanediol, 1,2-cyclopentanediol, 1,5-pentanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 2,5-hexanediol, 1,4-cyclohexanedimethanol, 1,3-benzyldimethanol, 4,8-bis(hydroxymethyl)tricyclo[5.2.1.0] 2,6 decane, dipropylene glycol, 1,1,1-trimethylolpropane, glycerol, 1,2,6-hexanetriol, 2,6-bis(hydroxymethyl)cresol, pyrogallol, resorcinol, pentaerythritol, ribose, arabinose, xylose, lyxose, ribulose and xylulose. A mixture of dipropylene glycol and 1,1,1-trimethylolpropane is particularly preferred.

[0131] Mixed-functional compound (c3):

[0132] In one embodiment, the compound (c3) contains at least one hydroxyl and / or amino functional group and at least one further functional group, which is selected from the functional groups of the resin (A) or capable of polymerizing with them. Further, in terms of its structure, the compound (c3) is not further restricted.

[0133] For example, further functional groups can have epoxy, oxetane, vinyl ether, and / or (meth)acrylate functionality. Preferably, the further functional groups of the compound with mixed functionality are epoxy groups, (meth)acrylate groups, and combinations thereof.

[0134] Examples of epoxy-functional compounds (c3) are pre-extended epoxy resins.

[0135] Examples of oxetane-functional compounds (c3) are 1-(oxiran-2-yl)ethan-1-ol, 2-(oxiran-2-yl)ethan-1-ol, 2-(oxiran-2-yl)-1-phenylethan-1-ol, 2-[(oxiran-2-yl)methoxy]ethan-1-ol, 3-ethyl-3-(hydroxymethyl)oxetane (Aron Oxetan OXT-101).

[0136] Examples of (meth)acrylate-functional compounds (c3) are 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, hydroxyethylhexyl acrylate, hydroxyisobutyl acrylate, 2-hydroxymethyl acrylate, hydroxyethylhexyl methacrylate.

[0137] Examples of vinyl-functional compounds (c3) are 2-hydroxyethyl vinyl ether, hydroxybutyl vinyl ether (HBVE), diethylene glycol vinyl ether, triethylene glycol vinyl ether, 1,4-cyclohexanedimethanol vinyl ether, 3-aminopropyl vinyl ether (3-aminopropyl vinyl ether, APVE).

[0138] The examples mentioned should not be construed as final or restrictive.

[0139] In the composition of the present invention, component (C) is contained in a proportion of at least 20 wt%, preferably at least 40 wt%, and particularly preferably at least 50 wt%. For complete dissolution in the presence of moisture, a proportion greater than 50 wt% is preferred.

[0140] Synthesis of polyacetal-bridged compound (C):

[0141] The synthesis of compound (C) can be carried out in one or two steps. In the case of one-step synthesis, in the presence of an acid as a catalyst, all the reaction partner substances (c1, c2 and c3) are mixed and placed at a temperature of 20 - 100 °C, preferably 20 - 80 °C, for 1 - 24 hours, preferably 1 - 6 hours, with stirring. After the reaction is completed, the catalyst is neutralized by adding an amine, preferably a secondary amine. The resulting salt and the excess amine can be removed, for example, by filtration.

[0142] In the case of two-step synthesis, in the first step, a polyacetal intermediate product having more than two hydroxyl groups can be formed by reacting compounds (c1) and (c2), and then it can be further functionalized with a linking agent (such as bifunctional isocyanates (HDI, IPDI), dicarboxylic acid halides (oxalyl chloride) or dicarboxylic anhydrides (MHTPA, MHHPA, glutaric anhydride)) with a suitable mixed-functional compound (c3) by methods known to those skilled in the art. In addition, the polyacetal intermediate product having more than two hydroxyl groups can react with a mixed-functional compound to form component (C), and the mixed-functional compound has a hydroxyl group-reactive functional group (such as an isocyanate group), as well as a further resin component (A) functional group or a group capable of polymerizing with it.

[0143] (D) Promoter

[0144] In order to shorten the time before separation and / or dissolution in the presence of moisture, an additional promoter can be added to the composition. In particular, a foaming agent (D1) is used, such as inorganic carbonates, tartrates, polyphosphates, azo compounds, azides and expandable microspheres.

[0145] As a further promoter, an acid (D2) can be used. In particular, organic acids such as acrylic acid, oxalic acid, citric acid or p-toluenesulfonic acid are suitable.

[0146] It is also possible to use a photoacid latent acid that releases an acid upon irradiation.

[0147] In the composition of the present invention, the promoter (D) can be used alone or in combination.

[0148] In the composition of the present invention, component (D) is contained in a proportion of 0 - 15 wt%, preferably 0 - 10 wt%, and particularly preferably 1 wt% - 5 wt%.

[0149] Component (E): Additive

[0150] In addition, the described composition may contain an optional ingredient as additive (E). Preferably, additive (E) is selected from the group consisting of fillers, dyes, pigments, anti-aging agents, fluorescent agents, stabilizers, polymerization accelerators, sensitizers, binders, desiccants, cross-linking agents, flow improvers, wetting agents, thixotropic agents, diluents, toughening agents, polymeric thickeners, flame retardants, corrosion inhibitors, plasticizers, and tackifiers.

[0151] The above list of additives should be considered exemplary and not restrictive.

[0152] Formulation of the composition of the present invention

[0153] The formulation of the composition of the present invention comprises at least components (A) to (C). In addition, accelerator (D) and additive (E) may be contained.

[0154] In a first embodiment, based on the total weight of the composition, the composition comprises the following components or consists of the following components:

[0155] (A) 1 wt% to 70 wt% of at least one curable resin component (A);

[0156] (B) 0.001 wt% to 70 wt% of at least one initiator and / or at least one curing agent for the polymerization of the curable resin component;

[0157] (C) 20 wt% to 95 wt% of at least one polyacetal bridging resin component;

[0158] (D) 0 to 15 wt% of an accelerator.

[0159] (E) 0 to 70 wt% of further additives selected from the group consisting of fillers, dyes, pigments, anti-aging agents, fluorescent agents, stabilizers, polymerization accelerators, sensitizers, binders, desiccants, cross-linking agents, flow improvers, wetting agents, thixotropic agents, reactive and non-reactive diluents, toughening agents, polymeric thickeners, flame retardants, corrosion inhibitors, plasticizers, tackifiers, and combinations thereof.

[0160] The composition of the present invention is preferably provided as a one-pack composition.

[0161] Use of the composition of the present invention

[0162] The composition of the present invention is particularly suitable for forming adhesives, coatings, and packages that can be redissolved and separated. For expensive components, for example, they can be applied as a protective layer during the manufacturing process and subsequently removed under mild conditions. Uses in joining schemes for electronics applications, together with recycling at the end of the device life to allow recovery of the components, are also conceivable.

[0163] In particular, the composition is suitable as a support material for the manufacture of additive manufacturing components. The advantage of this composition compared to comparable materials is that, under mild conditions, they can be removed from the component, leaving essentially no residue. Since the polyacetal bridging resin component (C) is incorporated into the resin matrix, the cured composition simultaneously has the characteristics of excellent cohesion and reliable mechanical properties as long as they are not exposed to the separation conditions.

[0164] In addition, the composition can be used as a temporary fixing material for the manufacture of so-called fan-out wafer level packages (FOWLP). In particular, the composition is suitable as a temporary carrier for the process disclosed in the scientific publication "Opportunities of Fan-out Wafer Level Packaging (FOWLP) for RF applications" by T. Braun, M. Topper, and K.-D. Lang, IEEE, 16th Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems (SiRF) 2016.

[0165] Curing of the composition of the present invention

[0166] The composition of the present invention can be cured by thermal and / or actinic radiation, especially UV radiation. The polyacetal bridging resin component (C) has no effect on typical curing conditions because it polymerizes into the resin matrix.

[0167] Measurement methods / devices used and definitions

[0168] Below, the composition shown in Table 1 and the measurement methods and definitions used in the experiment will be described.

[0169] Irradiation

[0170] To activate the photoinitiator (B), the composition of the present invention was irradiated with a DELOLUX 20 / 365 LED lamp from DELO Industrie Klebstoffe GmbH & Co. KGaA for 60 seconds, with an emission maximum at 365 nm and an intensity of 200 ± 20 mW / cm 2 .

[0171] Curing

[0172] "Crosslinking" or "curing" is defined as a polymerization or addition reaction beyond the gel point. The gel point is the point at which the storage modulus G' becomes equal to the loss modulus G". Curing of the sample is carried out at room temperature for 7 days.

[0173] Room temperature

[0174] Room temperature is defined as 23 ± 2 °C.

[0175] Verification of the progress of the reaction for forming component (C)

[0176] With the aid of IR spectroscopy, the progress of the reaction for forming the polyacetal intermediate and the subsequent reaction with the mixed-functional compound (c3) was evaluated. For this purpose, an ALPHA infrared spectrometer from Bruker was used, and the changes in the vibration bands mentioned below were traced. Once the relevant bands disappeared and / or the bands no longer changed, the reaction was considered complete.

[0177] Testing of the separation and dissolution properties of the composition

[0178] To evaluate the separability of the compositions of the present invention, two samples (sized 20 mm * 20 mm * 5 mm) made of glass and aluminum were bonded to each other using separate compositions, with an overlap of 5 mm and a layer thickness of 0.1 mm.

[0179] After successful curing, the samples were attached to a heavy object with the aid of a fixture and placed in a water bath at 80 °C (pH 7). The time elapsed before the joint connector broke was measured. After the joint connector broke, the samples were removed and the residual traces of the cured composition were examined.

[0180] To determine the solubility of the compositions of the present invention, a film of the composition to be tested, sized 3 × 3 cm and 200 μm thick, was cured at 365 nm for 60 s. Then the film was placed in a water bath at 80 °C and pH 3. Once no residue of the film was visually detectable, the time was recorded.

[0181] Determination of glass transition temperature

[0182] DSC measurements of reactivity and glass transition were carried out using a differential scanning calorimeter (DSC) of type DSC 822e or DSC 823e from Mettler Toledo.

[0183] For this purpose, a liquid sample of 16 mg - 20 mg was weighed into an aluminum crucible (40 μL) with a needle. The crucible was closed with a lid provided with holes, and the sample was measured with the following steps: (1) isothermal, 0 °C, 2 min; (2) dynamic 0 - 250 °C, 10 °K / min; (3) dynamic 250 °C - 0 °C, -10 °K / min; (4) isothermal, 0 °C, 3 min; (5) dynamic 0 - 250 °C, 20 °K / min. In all steps, the treatment gas was air (volume flow rate 30 mL / min).

[0184] The heating steps (2) and (5) were evaluated for reactivity and glass transition, respectively. The reaction enthalpy was determined by using a spline curve as the baseline and scaling it to the weighed sample, and its quantity was given as the heat release energy. The glass transition was analyzed using the tangent method.

[0185] Determination of elongation at break

[0186] Shouldered bars of a specified size (dimensions 25 × 5.5 × 2 mm, measuring distance 10 × 2 × 2 mm) were cast from the composition. The shouldered bars were irradiated from each side for 60 s (DELOLUX 20 / 365; intensity: 200 mW / cm 2 ). Subsequently, the shouldered bars were pulled apart in a tensile testing machine from Zwick at a speed of 30 mm / min, and the cohesion and elongation at break were determined according to DIN EN ISO527.

[0187] Examples of formulations:

[0188] Component (A): Cationically polymerizable component

[0189] (A1) Epoxy-containing compound

[0190] (A1-1): 3,4-epoxycyclohexylmethyl-3’,4’-epoxycyclohexane carboxylate, which can be obtained from Daicel Corporation under the trade name Celloxide 2021P.

[0191] (A2) Oxetane-containing compound

[0192] (A2-1): OXT-221 = bis[1-ethyl(3-oxetanyl)]methyl ether, which can be obtained from Toagosei Co., Ltd.

[0193] (A4) Free-radically curable (radiation-curable) compound

[0194] (A4-1): Acrylic acid, available from Sigma-Aldrich.

[0195] (A4-2): SR256 = 2-(2-ethoxyethoxy)ethyl acrylate, available from Sartomer.

[0196] (A4-3): SR495B = ε-caprolactone acrylate, available from Sartomer.

[0197] (A4-4): DMAA = N,N-dimethylacrylamide.

[0198] Component (B): Curing agent and / or initiator

[0199] (B4) Cationic photoinitiator

[0200] (B4-1): Irgacure 290 = tris(4-((4-acetylphenyl)thio)phenyl)sulfonium tetrakis-(perfluorophenyl)borate, available from IGM Resins.

[0201] (B6) Free-radical photoinitiator

[0202] (B6-1): Irgacure 819 = bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, available from IGM Resins.

[0203] Examples of the synthesis of polyacetal compound (C):

[0204] (c1) At least bifunctional vinyl ether

[0205] (c1-1): Triethylene glycol divinyl ether, available from BASF SE.

[0206] (c2) At least bifunctional alcohol

[0207] (c2-1) Dipropylene glycol

[0208] (c2-2) 1,1,1-Tris(hydroxymethyl)propane

[0209] (c3) Mixed-functional compound

[0210] (c3-1) OXT-101 = 3-ethyloxetane-3-methanol, available from Toagosei.

[0211] (c3-2) 4-Hydroxybutyl acrylate

[0212] (c3-3) Karenz AOI = 2-Isocyanatoethyl acrylate, available from Showa Denko K.K.

[0213] Component (D): Promoter

[0214] (D1) Acidic promoter

[0215] (D1-1): Oxalic acid

[0216] (D2) Expansive microspheres

[0217] (D2-1): Expancel Partikel 031DUX 40, available from Nouryon

[0218] Component (E): Additive

[0219] (E1-1): Thixotropic agent HDK N 20, available from Wacker

[0220] (C1): Formation of oxetane-functionalized polyacetal

[0221] Under a nitrogen atmosphere, 80.0 g (0.388 mol, 11 Eq.) of triethylene glycol divinyl ether (c1-1), 38.2 g (0.282 mol, 8 Eq.) of dipropylene glycol (c2-1), 4.73 g (0.035 mol, 1 Eq.) of 1,1,1-tris(hydroxymethyl)propane (c2-2), 13.3 g (115 mol, 3.25 Eq.) of Aron OXT-101 (c3-1) and 222 mg (2.47 mmol, 0.07 Eq.) of oxalic acid (D1-1) were charged into a baked container. Then, the reaction mixture was maintained at 80 °C with continuous stirring until no change in the OH vibration band at 3405 cm -1 was observed in the IR.

[0222] After that, 260 mL of ethyl acetate was added to the reaction mixture, and 6.8 g of activated carbon was added with vigorous stirring. Then, the solid was filtered off, and the supernatant solvent was removed under reduced pressure. 100 g (74%) of oxetane-functionalized polyacetal (C1) with a viscosity of 1.461 mPas was obtained.

[0223] (C2): Formation of epoxy-functionalized polyacetal

[0224] Under a nitrogen atmosphere, 175 g (0.865 mol, 8.5 Eq.) of triethylene glycol divinyl ether (c1-1), 117 g (0.865 mol, 8.5 Eq.) of dipropylene glycol (c2-1), 13.7 g (0.102 mol, 1 Eq.) of 1,1,1-tris(hydroxymethyl)propane (c2-2), and 640 mg (7.13 mmol, 0.07 Eq.) of oxalic acid (D1-1) were charged into a baked container. Then, the reaction mixture was heated to 85 °C with continuous stirring for 4 h. Thereafter, 220 mg (1.95 mmol, 0.077 Eq.) of 1,4-diazabicyclo[2.2.2]octane was added to the reaction mixture, and the mixture was homogenized.

[0225] Then, 300 mL of ethyl acetate was added to the reaction mixture, and 15.3 g of activated carbon was added with vigorous stirring. Thereafter, the solid was filtered off, and the supernatant solvent was removed under reduced pressure. 275 g (96%) of polyacetal intermediate I was obtained as an oily substance.

[0226] Under dry air, 100 g (0.063 mol, 1 Eq.) of polyacetal intermediate I was heated to 55 °C, and 14.0 g (0.120 mol, 1.9 Eq.) of glutaric anhydride was added. Thereafter, 680 mg (4.43 mmol, 0.07 Eq.) of 1,8-diazabicycloundecene was added, and the reaction mixture was stirred at 80 °C for 4 hours.

[0227] 133 g (0.528 mol, 8.35 Eq.) of 7-oxabicyclo[4.1.0]hept-3-ylmethyl-7-oxabicyclo[4.1.0]heptan-3-carboxylate (A1-1) was added and stirred until no change in the COOH vibration band between 3070 cm -1 and 3290 cm -1 was observed in the IR. After the reaction was completed, 240 g (97%) of epoxy-functionalized polyacetal (C2) with a viscosity of 3.386 mPas was obtained.

[0228] (C3): Formation of acrylate-functionalized polyacetal

[0229] Under a nitrogen atmosphere, 30.0 g (0.145 mol, 18 Eq.) of triethylene glycol divinyl ether (c1-1), 18.6 g (0.137 mol, 17 Eq.) of dipropylene glycol (c2-1), 1.08 g (8.08 mmol, 1 Eq.) of 1,1,1-tris(hydroxymethyl)propane (c2-2), 2.33 g (0.016 mmol, 2 Eq.) of 4-hydroxybutyl acrylate (c3-2), 102 mg (1.13 mmol, 0.14 Eq.) of oxalic acid (D1-1), 10.7 mg (0.05 mmol, 6 mEq.) of butylated hydroxytoluene, and 12.3 mg (0.10 mmol, 0.012 Eq.) of 4-methoxyphenol were charged into a baked container. Then, the reaction mixture was maintained at 80 °C with continuous stirring until no change in the OH vibration band at 3488 cm -1 was observed in the IR.

[0230] 45 g (88%) of acrylate-functionalized polyacetal (C3) with a viscosity of 1.812 mPas was obtained.

[0231] (C4): Formation of diisocyanate-linked acrylate-functionalized polyacetal

[0232] Under dry air, 8.44 g (0.038 mol, 2 Eq.) of isophorone diisocyanate was added to 30 g (0.019 mol, 1 Eq.) of polyacetal intermediate I. Then, 26.5 mg (0.02 mmol, 1.1 mEq.) of bismuth neodecanoate was added twice, and the reaction mixture was stirred at 80 °C for 5 h.

[0233] After that, 5.47 g (0.038 mol, 2 Eq.) of 4-hydroxybutyl acrylate (c3-2) was added, and the reaction was stirred until no change in the NCO vibration band at 2262 cm -1 was observed in the IR. 39 g (98%) of acrylate-functionalized polyacetal (C4) with a viscosity of 169.670 mPas was obtained.

[0234] Formation of monoisocyanate-linked acrylate-functionalized polyacetal (C5-C9)

[0235] First, after synthesizing polyacetal intermediate I, polyacetal intermediates II to V were formed from vinyl ether (c1-1) and polyols (c2-1) and (c2-2) in the presence of oxalic acid (D1-1) according to the equivalents described in Table 1.

[0236] Thereafter, under a nitrogen atmosphere, a baked container having 1 Eq. of polyacetal intermediate I - polyacetal intermediate V was charged with 7 mEq. of butylated hydroxytoluene (BHT) and 14 mEq. of 4 - methoxyphenol (HQMME). Then, 2 Eq. of a mixed - functionality compound (c3 - 3; Karenz AOI) and 3.5 mEq. of bismuth neodecanoate were added. The reaction mixture was maintained at 70 °C with continuous stirring until no change in the NCO vibration band (2239 cm -1 -2275 cm -1 ) was detected in the IR.

[0237] As an oil, an acrylate - functionalized polyacetal (C5 - C9) was obtained from polyacetal intermediate I to polyacetal intermediate V in a yield of >90%.

[0238] Table 1: Synthesis of polyacetal - bridged resin component C5 - C9

[0239]

[0240]

[0241] * Desired acetal number P i =[Theoretical number of polyacetal linkages]; assuming that each vinyl group of (c1 - x) reacts with the hydroxyl functional group of (c2 - x) to form a polyacetal group.

[0242] (C10): Formation of unfunctionalized polyacetal

[0243] Under a nitrogen atmosphere, a baked container was charged with 60.0 g (0.300 mol, 8.5 Eq.) of triethylene glycol divinyl ether (c1 - 1), 40.2 g (0.300 mol, 8.5 Eq.) of dipropylene glycol (c2 - 1), 4.68 g (0.025 mol, 1 Eq.) of 1,1,1 - tris(hydroxymethyl)propane (c2 - 2), 7.76 g (0.105 mol, 3 Eq.) of 1 - butanol, and 220 mg (2.40 mmol, 0.07 Eq.) of oxalic acid (D1 - 1). Then, the reaction mixture was heated to 85 °C with continuous stirring until no vinyl vibration band was observed at 1618 cm -1 .

[0244] 110 g (98%) of unfunctionalized polyacetal (C10) was obtained, having a viscosity of 223 mPas and no resin - component (A) functional groups.

[0245] Table 2: Examples of the formulation of the present invention (proportions in wt% based on the total weight of the formulation)

[0246]

[0247] Table 2: Continued

[0248]

[0249] Table 3: Comparative examples (proportions in wt% based on the total weight of the formulation)

[0250]

[0251] Compositions 1 - 3 of the present invention comprise a cationically curable system, each of which contains an oxetane-functionalized polyacetal-bridged resin component (C1) or an epoxy-functionalized polyacetal-bridged resin component (C2). The composition of Example 2 based on the oxetane-functionalized polyacetal-bridged resin component (C2) separates almost three times faster than the composition of Example 1 based on (C2). By adding 0.2 parts by weight of an acidic promoter (Example 3 of the present invention), the separation time can be further reduced by 12 minutes.

[0252] In Examples 4 and 5 of the present invention, based on acrylate-containing formulations, the separation time can also be accelerated by nearly one-third by adding expandable microspheres (D2-1). The composition of Example 5 of the present invention can dissolve within 24 h without leaving any residue.

[0253] The influence of the acetal number (which is a measure of the number of acetal functional groups in component (C)) becomes apparent in Examples 6 - 9 of the present invention. As the acetal number increases, the time before separation also shortens. The composition of Example 6 of the present invention (theoretical acetal number: 17) separates within 14 minutes, while the composition of Example 9 with 13 acetals separates within 24 minutes.

[0254] Examples 10 - 12 of the compositions of the present invention, together with Comparative Example 14, show the lower limit of the proportion of the polyacetal-bridged resin component (C). In Comparative Example 14, the proportion of polyacetal is less than 20 wt%. The time before separation exceeds one day. Examples 10 - 12 of the present invention show that as the proportion of polyacetal (C) increases, the separation time shortens.

[0255] Comparative Example 13 contains unfunctionalized polyacetal (C10) at a proportion of 70 wt%. Despite the high proportion, the cured composition takes more than one week to separate from the substrate. Since the polyacetal (C10) is not incorporated into the polymer network, Comparative Example 13 does not conform to the present invention.

Claims

1. A curable composition that is liquid at room temperature, the curable composition comprising: (A) At least one curable resin component selected from the group consisting of epoxy-containing compounds, oxetanes, vinyl ethers, (meth)acrylates, silanes, and combinations thereof; (B) At least one initiator and / or at least one curing agent for the polymerization of the curable resin component; and (C) At least one polyacetal bridging resin component obtainable by reacting at least one at least difunctional vinyl ether (c1) with at least one at least difunctional alcohol (c2) to form a polyacetal intermediate having more than two terminal vinyl ether groups or more than two terminal hydroxyl groups, and a) Reacting the polyacetal intermediate having more than two terminal vinyl ether groups with at least one mixed-functional compound (c3') having at least one hydroxyl group or at least one amino group, and at least one functional group of the at least one further curable resin component (A) or a group capable of polymerizing therewith; or b) Reacting the polyacetal intermediate having more than two terminal hydroxyl groups with a hydroxyl group-reactive linker and further reacting it with a mixed-functional compound (c3') or a difunctional curable resin component (A); or c) Reacting the polyacetal intermediate having more than two terminal hydroxyl groups with a mixed-functional compound (c3") having at least one isocyanate group and a functional group of the at least one further curable resin component (A) or a group capable of polymerizing therewith; Among them, Based on the total weight of the composition, the polyacetal bridging resin component (C) is present in the composition in a proportion of at least 20 wt%; and wherein at least one of the compounds (c1) and (c2) is trifunctional or has a higher functionality.

2. The composition according to claim 1, characterized in that, The reaction of the at least difunctional vinyl ether (c1) with the at least difunctional alcohol (c2) and the at least one mixed-functional compound (c3') or mixed-functional compound (c3") is carried out in a one-step synthesis.

3. The composition according to claim 1 or 2, characterized in that The curable resin component (A) comprises an epoxy-containing compound and / or an oxetane, and the composition comprises a curing agent (B1) selected from the group consisting of amines and / or acid anhydrides.

4. The composition according to claim 1 or 2, characterized in that, The curable resin component (A) comprises an epoxy-containing compound, an oxetane, and / or a vinyl ether, and the composition comprises an initiator for cationic polymerization.

5. The composition according to claim 1 or 2, characterized in that, The curable resin component (A) comprises a free-radically curable (meth)acrylate compound, and the composition comprises an initiator for free-radical polymerization.

6. The composition according to claim 1 or 2, characterized in that, The curable resin component (A) comprises an epoxy-containing compound and / or an oxetane and a radiation-curable compound, or a hybrid compound having an epoxy group and a radiation-curable group, and the composition comprises a curing agent from the group consisting of amines and / or acid anhydrides and an additional initiator for free-radical polymerization.

7. The composition according to claim 1 or 2, characterized in that, The at least difunctional vinyl ether (c1) is selected from the group consisting of aliphatic vinyl ethers, cycloaliphatic vinyl ethers, aromatic vinyl ethers, and combinations thereof.

8. The composition according to claim 7, characterized in that, The at least difunctional vinyl ether (c1) is a polar vinyl ether having a functionality of two to four.

9. The composition according to claim 8, wherein The at least difunctional vinyl ether (c1) is selected from diethylene glycol divinyl ether (DVE-2), triethylene glycol divinyl ether (DVE-3), 1,4-butanediol divinyl ether (BDDVE), 1,4-cyclohexanedimethanol divinyl ether (CHDM-di), 1,2,3-tris(vinyl-oxy)propane, trimethylolpropane trivinyl ether, 1,3,5-tris[(2-vinyloxy)ethoxy]benzene, 1,2,4-benzenetricarboxylic acid tris[4-(vinyloxy)butyl] ester, 1,3,5-tris(2-vinyloxyethyl)-1,3,5-triazine, 1,3,5-cyclohexanetri-methanol trivinyl ether, 1,1,1-tris-4-[2-(vinyloxy)ethoxy]phenyl ethane, tetra(vinyloxymethyl)methane, and combinations thereof.

10. The composition according to claim 1 or 2, characterized in that, The at least difunctional alcohol is selected from the group consisting of primary and secondary aliphatic alcohols, cycloaliphatic alcohols, aromatic alcohols, and combinations thereof.

11. The composition according to claim 10, wherein The at least difunctional alcohol has a functionality of two to five.

12. The composition according to claim 11, wherein The at least difunctional alcohol is selected from dipropylene glycol, 1,1,1-trimethylolpropane, glycerol, 1,2,6-hexanetriol, 2,6-bis(hydroxymethyl)-p-cresol, pyrogallol, resorcinol, pentaerythritol, ribose, arabinose, xylose, lyxose, ribulose, xylulose, and combinations thereof.

13. The composition according to claim 1 or 2, characterized in that, Further functional groups of the mixed functionality compound include epoxy groups, (meth)acrylate groups, and combinations thereof.

14. The composition according to claim 1 or 2, characterized in that, The mixed functionality compound is selected from glycidyl, pre-extended epoxy resins, 1-(oxiran-2-yl)ethan-1-ol, 2-(oxiran-2-yl)ethan-1-ol, 2-(oxiran-2-yl)-1-phenylethan-1-ol, 2-[(oxiran-2-yl)methoxy]ethan-1-ol, 3-ethyl-3-(hydroxymethyl)oxetane, 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, hydroxyethylhexyl acrylate, hydroxyisobutyl acrylate, 2-hydroxymethyl acrylate, hydroxyethylhexyl methacrylate, 2-hydroxyethyl vinyl ether, hydroxybutyl vinyl ether (HBVE), diethylene glycol vinyl ether, triethylene glycol vinyl ether, 1,4-cyclohexanedimethanol vinyl ether, 3-aminopropyl vinyl ether (APVE), and combinations thereof.

15. The composition according to claim 1 or 2, characterized in that, The polyacetal bridging resin component (C) has a molecular weight in the range of 2000 g / mol - 20,000 g / mol.

16. The composition according to claim 15, characterized in that, The polyacetal bridging resin component (C) has a molecular weight in the range of 2000 g / mol - 8000 g / mol.

17. The composition according to claim 1 or 2, characterized in that, Based on the total weight of the composition, respectively, the polyacetal bridging resin component (C) is present in the composition in a proportion of at least 40 wt%.

18. The composition according to claim 17, wherein Based on the total weight of the composition respectively, the polyacetal bridging resin component (C) is present in the composition in a proportion of at least 50 wt%.

19. The composition according to claim 1 or 2, characterized in that, The composition further comprises a promoter selected from the group consisting of a blowing agent and an organic acid.

20. The composition according to claim 1 or 2, characterized in that, Based on the total weight of the composition respectively, the composition comprises the following components or consists of the following components: 1 wt% to 70 wt% of the at least one curable resin component (A); 0.001 wt% to 70 wt% of the at least one initiator and / or at least one curing agent for the polymerization of the curable resin component; 20 wt% to 95 wt% of the at least one polyacetal bridging resin component; 0 to 15 wt% of a promoter for the hydrolytic cleavage of the polyacetal; 0 to 70 wt% of further additives selected from the group consisting of fillers, dyes, pigments, anti-aging agents, fluorescent agents, stabilizers, polymerization promoters, sensitizers, binders, desiccants, crosslinking agents, flow improvers, wetting agents, thixotropic agents, reactive and non-reactive diluents, toughening agents, polymerization thickeners, flame retardants, corrosion inhibitors, plasticizers, tackifiers, and combinations thereof.

21. A method for forming and redissolving a joint connector, wherein, a) applying the composition according to any one of the preceding claims to a first substrate and bringing the composition into contact with at least one further substrate to form an adhesive joint; b) curing the adhesive joint by exposure to heat and light to form a cured joint connector; and c) exposing the cured joint connector to moisture at a predetermined temperature for a predetermined period of time to dissolve and / or separate the cured joint connector from the substrate.

22. Use of the composition according to any one of claims 1 - 20 as a temporary support material for additive manufacturing structures.

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