Layered product including adherend, primer and sealant; method for producing same; primer composition; and use of dicarbonyl compound

Abstract

[Problem] To provide a layered product which has an adherend, a sealant on the adherend, and a primer between these, wherein the sealant can be separated from the adherend more easily than in the past. [Solution] A layered product which has an adherend, a sealant on the adherend, and a primer between the adherend and the sealant, wherein at least one of the sealant or the primer comprises: a polyurethane and / or a polyurea; and a dicarbonyl compound and wherein the dicarbonyl compound is in an amount of 12 % by volume to 90 % by volume, with respect to a total of the polyurethane and the polyurea and the dicarbonyl compound.

Description

LAYERED PRODUCT INCLUDING ADHEREND, PRIMER AND SEALANT;METHOD FOR PRODUCING SAME; PRIMER COMPOSITION; AND USE OF DICARBONYL COMPOUND[Technical Field]

[0001] The present disclosure relates to: a layered product including an adherend, a primer and a sealant; a method for producing same; a primer composition; and use of a dicarbonyl compound. In addition, the present invention also relates to an assembly in which a plurality of adherends are bonded to each other via an adhesive and a primer.[Background Art]

[0002] Layered products having an adherend, a sealant on the adherend, and a primer between these are known as construction materials, vehicle components, and so on. A variety of layered products are formed by applying sealants to adherends (for example, surfaces of construction materials and vehicle components) via a primer. In addition, assemblies in which a plurality of adherends are bonded to each other using an adhesive are also known, and adhesives can be bonded to adherends via a primer.

[0003] Research has been carried out into methods for recovering valuable materials from waste products.

[0004] Non-Patent Document 1 relates to a method for obtaining highly valuable chemical substances and materials from waste polymers following consumption. This document describes converting a urea bond in a polyurea into a vinylic amide by means of a heat treatment using acetylacetone, and using said vinylic amide.[Prior Art Documents][Non-Patent Literature]

[0005] [Non-Patent Document 1] Youwei Ma et al., Chemical Upcycling of Conventional Polyureas into Dynamic Covalent Poly(aminoketoenamide)s, Angew. Chem., 2023, 135, e202212870[Summary of the Invention][Problem to be Solved by the Invention]

[0006] Sealants and adhesives attached to adherends were not easy to separate or remove, and these could cause problems during reuse, disposal, and so on.

[0007] With this background in mind, a purpose of the present disclosure is to provide a layered product which has an adherend, a sealant on the adherend, and a primer between these, and in which the sealant can be separated from the adherend more easily than in the past. In addition, another purpose of the present disclosure is to provide a layered product in which an adhesive can be separated from adherends more easily than in the past in an assembly having a plurality of adherends bonded to each other via the adhesive and an accompanying primer.

[0008] Another purpose of the present disclosure is to provide a method for producing this type of layered product and a method for producing an assembly, and a further purpose of the present disclosure is to provide a primer composition able to be used in this type of layered product or assembly.

[0009] A further purpose of the present disclosure is to provide a method for using a dicarbonyl compound in debonding of a sealant or an adhesive and / or a primer bonded to anadherend. It should be noted that in the present invention, the term “debonding” can mean weakening adhesion between two members bonded to each other either directly or indirectly, or separating members from each other. For example, the term “debonding” can mean weakening adhesion between an adherend and a sealant or an adhesive (and also a primer) or separating these from each other in a layered product having an adherend, a sealant on the adherend, and a primer between these, or in an assembly having a plurality of adherends bonded to each other via an adhesive and an accompanying primer.

[0010] In addition, the term “heat-dependent debonding” can mean weakening adhesion between two members or separating these members from each other by subjecting two members, which are bonded to each other either directly or indirectly, to a heat treatment.[Means for Solving the Problem]

[0011] The problem to be addressed by the present disclosure can be solved by the following embodiments of the present invention.<Embodiment 1>A layered product which has an adherend, a sealant on the adherend, and a primer between the adherend and the sealant, whereinat least one of the sealant or the primer contains: a polyurethane and / or a polyurea; and a dicarbonyl compound.<Embodiment 2>The layered product according to embodiment 1, wherein the sealant and the primer both contain a polyurethane and / or a polyurea, and the primer contains a dicarbonyl compound.<Embodiment 3>The layered product according to embodiment 1 or embodiment 2, wherein the content of the dicarbonyl compound in the sealant and / or the primer is 0.1 -80 vol% relative to the total amount of the polyurethane and / or polyurea and the dicarbonyl compound.<Embodiment 4>The layered product according to any one of embodiments 1 -3, wherein the dicarbonyl compound includes at least one selected from among a 1 ,3 -diketone, an acetoacetic acid ester and an acetoacetic acid amide.<Embodiment 5>The layered product according to any one of embodiments 1 -4, wherein the dicarbonyl compound includes at least one selected from among acetylacetone and methyl acetoacetate.<Embodiment 6>The layered product according to any one of embodiments 1 -5, wherein the adherend is formed from a material selected from the group consisting of plastics, ceramics, concrete, rubbers, glasses, metals and mortar.<Embodiment 7>The layered product according to any one of embodiments 1 -6, wherein the adherend is a construction material or a vehicle component.<Embodiment 8>A primer composition that contains: a polyurethane and / or a polyurea; and a dicarbonyl compound.<Embodiment 9>A method for producing a layered product, whereinthe layered product has an adherend, a sealant on the adherend, and a primer between the adherend and the sealant, the method comprises(a) providing an adherend,(b) applying a primer composition to the adherend to form a primer layer,(c) applying a sealant composition to the primer layer, and(d) curing the applied sealant composition to form a sealant,andat least one of the sealant composition or the primer composition contains: a polyurethane and / or a polyurea; and a dicarbonyl compound.The sealant composition is preferably applied by being coated.<Embodiment 10>Use of a dicarbonyl compound for heat-dependently debonding a sealant or an adhesive and / or a primer which contain a polyurethane and / or a polyurea and are bonded to an adherend.<Embodiment 11>An assembly which has a first adherend, an adhesive, and a second adherend, and in which the first adherend and the second adherend are joined to each other by the adhesive, whereinat least one of the adhesive or a primer used together with the adhesive contains: at least one polymer obtained from a combination of a polyisocyanate and a polyol and / or polyamine; and a dicarbonyl compound.<Embodiment 12>The assembly according to embodiment 11, wherein the adhesive and the primer are substantially enclosed on all sides by the first adherend and the second adherend.<Embodiment 13>The assembly according to embodiment 11 or 12, which also has at least one of the characteristics set forth in embodiments 2-6 (in this case, the term “sealant” should be read as “adhesive”).[Effects of the Invention]

[0012] The present invention is capable of providing a layered product which has an adherend, a sealant on the adherend, and a primer between the adherend and the sealant, and which can be heat-dependently debonded. Due to this configuration, the sealant can be separated from the adherend more easily than in the past. In addition, the present invention is capable of providing an assembly having a plurality of (for example, two) adherends bonded to each other via an adhesive and an accompanying primer, wherein the assembly can be heat-dependently debonded. Due to this configuration, the adhesive can be separated from the adherends more easily than in the past. In addition, the present invention is capable of providing a method for producing this type of layered product and a method for producing an assembly, and providing a primer composition able to be used in this type of layered product or assembly. Furthermore, the present invention is capable of providing a method for using a dicarbonyl compound capable of debonding a sealant or an adhesive and / or a primer bonded to an adherend where necessary.[Brief Description of Drawings]

[0013] [FIG. 1] FIG. 1 is a cross-sectional schematic view of a layered product according to the present invention.[FIG. 2] FIG. 2 is a photograph that shows results of adhesive properties tests according to Working Example 1 (first test: S I, second test: S2, third test: S3).[FIG. 3] FIG. 3 is a photograph that shows results of adhesive properties tests according to Comparative Example 1 (first test: S I , second test: S2, third test: S3).[Embodiments of the Invention]

[0014] <<Layered product>>The layered product according to the present invention isa layered product which has an adherend, a sealant on the adherend, and a primer between the adherend and the sealant, whereinat least one of the sealant or the primer contains: a polyurethane and / or a polyurea; and a dicarbonyl compound.

[0015] As explained above, a variety of layered products are formed by applying sealants toadherends (for example, surfaces of vehicles, construction materials, and so on) via a primer (for example, by coating, such as in the case of vehicle components, or by filling, such as in the case of building joints). In conventional layered products, sealants attached to adherends were not easy to remove, and these could cause problems during reuse, disposal, and so on.

[0016] Conversely, the inventors of the present invention found that by incorporating a dicarbonyl compound in a sealant and / or primer containing a polyurethane and / or a polyurea, the sealant can be heat-dependently debonded where necessary (this is also known as “debonding-on-demand”).

[0017] Specifically, by bringing about heat-dependent decomposition of a polyurethane and / or a polyurea by using a dicarbonyl compound, it is possible to weaken the integrity of a sealant and / or a primer and / or weaken adhesive strength to an adherend, thereby enabling the sealant (and also the primer) to be separated and removed (by peeling off etc) from the adherend more easily.

[0018] According to the present invention, when a sealant (and also a primer) needs to be removed from a construction material or a vehicle windscreen or body, or the like, during waste processing and so on, the sealant can now be separated relatively easily by means of a heat treatment.

[0019] Embodiments and constituent elements of the invention according to the present disclosure will now be explained in greater detail.

[0020] <Dicarbonyl compound>The dicarbonyl compound has two carbonyl groups (-C(=O)-) in the molecule. The dicarbonyl compound is preferably a 1 ,3 -dicarbonyl compound. The 1 ,3 -dicarbonyl compound has a structure in which two carbonyl groups are directly bonded to one carbon atom.

[0021] Examples of dicarbonyl compounds include 1 ,3 -diketones, 3-oxobutyric acid derivatives, acetoacetic acid esters and acetoacetic acid amides. It is possible to use one dicarbonyl compound alone, or a combination of two or more types thereof. Further examples of dicarbonyl compounds include [3-keto acid esters and [3-keto acid amides.

[0022] Examples of 1,3-diketones include acetylacetone and 2,4-hexadione.

[0023] In addition, examples of 1,3 -diketones include compounds in which substituent groups at both terminals are longer chain alkyl groups than methyl groups, and compounds condensed into the form of a ring such as a cyclohexane ring.

[0024] Examples of 1,3-diketones include compounds having general formula (1) below.

[0025] [Compound 1]( 1 )

[0026] In formula (1), R1and R2are each independently an alkyl group having 1 -10 carbon atoms, or may together form a cyclic structure.

[0027] In formula (1), it is preferable for R1and R2to be each independently an alkyl grouphaving 1 -5 carbon atoms, more preferably an alkyl group having 1 -3 carbon atoms, and particularly preferably a methyl group or an ethyl group.

[0028] In a case where R1and R2in formula ( 1) together form a cyclic structure, said cyclic structure may be, for example, an optionally substituted cycloalkylene ring (for example, a cyclohexane ring). Examples of substituent groups include alkyl groups having 1 -3 carbon atoms (for example, methyl groups or ethyl groups).

[0029] Examples of acetoacetic acid esters include methyl acetoacetate and ethyl acetoacetate. Methyl acetoacetate has a relatively high boiling point, and can therefore be used particularly advantageously to achieve a highly stable debonding effect.

[0030] In addition, examples of acetoacetic acid esters include compounds having general formula (2) below.

[0031] [Compound 2]( 2 )

[0032] In formula (2), R3and R4are each independently an alkyl group having 1 -10 carbon atoms, or may together form a cyclic structure.

[0033] In formula (2), it is preferable for R3and R4to be each independently an alkyl group having 1 -5 carbon atoms, more preferably an alkyl group having 1 -3 carbon atoms, and particularly preferably a methyl group or an ethyl group.

[0034] In a case where R3and R4in formula (2) together form a cyclic structure, said cyclic structure may be, for example, an optionally substituted cycloalkylene ring (for example, a cyclohexane ring). Examples of substituent groups include alkyl groups having 1 -3 carbon atoms (for example, methyl groups or ethyl groups).

[0035] Examples of acetoacetic acid amides include N,N -dimethylacetoacetamide and N,N-diethylacetoacetamide. Examples of acetoacetic acid amides include compounds having condensed carbon chains and compounds having heterocyclic rings containing heteroatoms other than nitrogen atoms (N) (for example, an oxygen atom in morpholine).

[0036] In addition, examples of acetoacetic acid amides include compounds having general formula (3) below.

[0037] [Compound 3]( 3 )

[0038] In formula (3), R5to R7are each independently an alkyl group having 1 -10 carbon atoms.

[0039] In formula (3), it is preferable for R5to R7to be each independently an alkyl group having 1 -5 carbon atoms, more preferably an alkyl group having 1 -3 carbon atoms, and particularly preferably a methyl group or an ethyl group.

[0040] In the layered product according to the present invention, at least one of the sealant or the primer contains a dicarbonyl compound in order to achieve superior heat-dependent debonding. A dicarbonyl compound may be contained in both the sealant and the primer. A dicarbonyl compound is preferably contained in only the primer. Thereby, the sealant can be removed without remaining on the adherend.

[0041] The dicarbonyl compound is preferably a liquid at room temperature. In this case, the applicability of the sealant and / or primer containing the dicarbonyl compound is further improved, and production of a layered product is relatively easy.

[0042] <Content values of components>In one embodiment, the content of the dicarbonyl compound in the sealant, the primer, or the sealant and the primer, is 0.1 -80 vol% relative to the total amount of the polyurethane and / or polyurea and the dicarbonyl compound. The content of the dicarbonyl compound may be 0.5 vol% or more, 1 vol% or more, 2 vol% or more, 5 vol% or more, 10 vol% or more, 12 vol%, 15 vol%, 20 vol%, 25 vol%, 30 vol%, or 35 vol% or more, and / or may be 90 vol% or less, 85 vol% or less, 80 vol% or less, 75 vol% or less, 70 vol% or less, 65 vol% or less, 60 vol% or less, or 55 vol% or less. The content of the dicarbonyl compound is preferably 1 -75 vol%, more preferably 5-70 vol%, and further preferably 10-65 vol%.

[0043] By ensuring that the amount of the dicarbonyl compound in the sealant and / or primer falls within the range mentioned above, it is possible to ensure sufficient amounts of components (especially polymer components) required for functions of the sealant and / or primer (for example, adhesive properties, waterproofing properties and sealing properties), thereby ensuring that the sealant and / or the primer exhibit(s) satisfactory performance. In addition, by ensuring that the amount of the dicarbonyl compound in the sealant and / or primer falls within the range mentioned above, it is possible to ensure a sufficient amount of the dicarbonyl compound, thereby ensuring a satisfactory debonding effect.

[0044] <Polyurethane and / or polyurea>At least one of the sealant or the primer contains a polyurethane and / or a polyurea. The polyurethane and / or polyurea can impart the sealant and primer with desired functions (sealing properties, waterproofing properties, adhesive properties, and so on).

[0045] The polyurethane and / or the polyurea can be obtained through a polymerisation reaction between a polyisocyanate and a polyol and / or polyamine, and contain, for example, a urethane group and / or a urea group.

[0046] It is preferable for both the sealant and the primer to contain a polyurethane and / or a polyurea. In this case, compatibility between the sealant and the primer is improved, meaning that adhesive properties therebetween can be enhanced.

[0047] The polyurethane can be obtained through a polymerisation reaction between a polyisocyanate and a polyol. The polyurea can be obtained through a polymerisation reaction between a polyisocyanate and a polyamine. It is possible to use one of these polymers alone, or a combination thereof.

[0048] (Polyisocyanate)The term “polyisocyanate” means a compound having two or more isocyanate groups.

[0049] Polyisocyanates include diisocyanates. Examples of diisocyanates include aromatic, aliphatic and alicyclic diisocyanates having molecular weights of less than 500 g / mol.

[0050] Specific polyisocyanate compounds include all isomers of toluene diisocyanate (TDI) (isomerically pure forms and mixtures of multiple isomers), naphthalene - 1 ,5 -diisocyanate (NDI), naphthalene-l,4-diisocyanate (NDI), diphenylmethane-4,4’-diisocyanate (MDI), diphenylmethane-2,4’-diisocyanate, mixtures of 4,4’-diphenylmethane diisocyanate and the 2,4’ -isomer thereof, xylylene diisocyanate (XDI), 4,4’ -di-phenyldimethylmethane diisocyanate, di- and tetra-alkyl-diphenylmethane diisocyanates, 4,4’ -dibenzyl diisocyanate, 1,3-phenylene diisocyanate and 1,4-phenylene diisocyanate. Examples of suitable alicyclic diisocyanates include hydrogenated products of the aromatic diisocyanates mentioned above, such as 4,4’ -dicyclohexylmethane diisocyanate (H12MDI), cyclohexane - 1 ,4-diisocyanate, hydrogenated xylylene diisocyanate (H6XDI), 1 -methyl-2,4-diisocyanato-cyclohexane and hydrogenated p-tetramethylxylylene diisocyanate (m-TMXDI, p-TMXDI). Other suitable diisocyanates include l -isocyanatomethyl-3-isocyanato-l ,5,5-trimethyl-cyclohexane (isophorone diisocyanate, IPDI) and dimer fatty acid diisocyanates.Examples of aliphatic diisocyanates include tetramethoxybutane-l ,4-diisocyanate, butane-l,4-diisocyanate, hexane-l,6-diisocyanate (HDI), l,6-diisocyanato-2,2,4-trimethylhexane, 1 ,6-diisocyanato-2,4,4-trimethylhexane, lysine diisocyanate and 1 , 12-dodecane diisocyanate (C12DI). It is possible to use one of these compounds alone, or a combination thereof.

[0051] (Polyol compound)The polyol compound has two or more OH groups in the molecule. Examples of polyol compounds include polyether polyols and polyester polyols, and specific examples include difunctional and / or trifunctional polypropylene glycol and polyethylene glycol, linear difunctional polyethylene glycol monomethyl ether, random and / or block copolymers of ethylene oxide and propylene glycol, and polytetramethylene glycol (poly(oxytetramethylene)glycol; poly-THF) produced by acid polymerisation of tetrahydrofuran.

[0052] More specific examples of polyols include polyesters produced through condensation of: dicarboxylic acids or tricarboxylic acids, such as adipic acid, sebacic acid, glutaric acid, azelaic acid, undecanedioic acid, dodecanedioic acid, 3,3 -dimethylglutaric acid, terephthalic acid, isophthalic acid, hexahydrophthalic acid, dimer fatty acids and mixtures thereof; and low molecular weight diols or triols, such as ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, 1,4 -butane diol, 1,6-hexane diol, 1,8-octane diol, 1, 10-decane diol, 1, 12-dodecane diol, dimer fatty alcohols, glycerol, trimethylolpropane and mixtures thereof.

[0053] Examples of polyamines include aliphatic, alicyclic and arylaliphatic primary diamines, aliphatic, alicyclic and arylaliphatic primary triamines, ether group -containing aliphatic primary diamines, primary polyoxyalkylene triamines that are products obtained by amination of polyoxyalkylene triols, polyamines having two primary aliphatic amino groups and a tertiary amino group, polyamines having three primary aliphatic amino groups and a tertiary amino group, polyamines having two primary aliphatic amino groups and a secondary amino group, polyamines having primary and secondary amino groups, aromatic polyamines, and polyamideamines.

[0054] Specific examples of polyamines include 1,3 -pentanediamine (DAMP), l,5-diamino-2-methylpentane (MPMD), 2-butyl-2-ethyl-l,5-pentanediamine (C 11 -neodiamine), 1,6-hexanediamine, 2,2,4- and 2,4,4-trimethylhexamethylenediamine (TMD), 1, 12-dodecane diamine , 1,3-diaminocyclohexane, bis-(4-aminocyclohexyl)methane (H12-MDA), bis-(4-amino-3-methylcyclohexyl)methane, 1 - amino -3 -aminomethyl -3, 5, 5 -trimethylcyclohexane (IPDA), 1 ,3 -bis-(aminomethyl)cyclohexane, 1,3-bis(aminomethyl)benzene (MXDA), bis-hexamethylenetriamine (BHMT),diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), pentaethylenehexamine (PEHA), higher homologs of linear polyethyleneamines, such as polyethylene polyamines having 5 -7 ethyleneamine units (HEPA), dipropylenetriamine (DPTA), N-(2-aminoethyl)-l ,3-propanediamine (N3 -amine), N,N’-bis(3-aminopropyl)ethylenediamine (N4-amine), and polyoxyalkylenediamines and polyoxyalkylenetriamines having molecular weights of 200-500 g / mol.

[0055] <Layered product>The layered product has an adherend, a sealant on the adherend, and a primer between the adherend and the sealant. The adherend, primer and sealant may be layered in this order so as to overlap each other. These may be bonded to each other in the layered product.

[0056] FIG. 1 is a schematic view of the layered product according to the present invention. This drawing is an illustrative example for explaining the present invention, and is not to scale. A layered product 10 in FIG. 1 has a structure in which an adherend 11 , a primer 12 and a sealant 13 are layered in this order.

[0057] This type of layered product 10 can be produced by, for example, coating a primer composition on a surface of the adherend 11 , drying as appropriate to form the primer 12, coating a sealant composition on the coated primer 12, and carrying out a curing treatment to form the sealant 13. In the layered product 10, the adherend 11 and the sealant 13 are bonded to each other with the primer 12 interposed therebetween.

[0058] <Adherend>The adherend may have a surface for disposing the primer and the sealant.

[0059] The shape of the adherend is not particularly limited, but may be, for example, plate -like.

[0060] The adherend may be formed from a material selected from the group consisting of plastics, ceramics, concrete, rubbers, glasses, metals and mortar. It is preferable for the adherend to be made from a material selected from the group consisting of plastics, glasses and metals.

[0061] Examples of plastics include polyolefin resins (for example, polyethylene, polypropylene and polybutylene), polyester resins (for example, poly(ethylene terephthalate), poly(butylene terephthalate) and poly(ethylene naphthalate)), nylon resins, poly(methyl methacrylate) resins, polycarbonate resins, polystyrene resins, acrylonitrile-styrene copolymer resins, poly(vinyl chloride) resins, acetate resins, acrylonitrile-butadiene-styrene resins, poly(phenylene sulphide) resins, polyether imide resins, polysulfone resins, polyether sulfone resins, polyketone resins, polyether ketone resins, polyether ether ketone resins, polyimide resins, polyamide resins and fluororesins.Examples of glasses include soda lime glass, quartz glass, borosilicate glass and aluminosilicate glass.

[0062] Examples of metals include iron and aluminium. In particular, the adherend may be a metal sheet or a coated steel sheet, and may also be a stainless steel sheet, an ED sheet obtained by electrodeposition (ED) on a stainless steel sheet, or an aluminium sheet.

[0063] The adherend may be a construction material or a vehicle component. More specifically, examples of the adherend include wall materials, gypsum boards, sashes and flooring materials, and also include vehicle components (for example, interior components and exterior components), and window materials. Examples of vehicle components include bodies, front doors, rear doors, back doors, front bumpers, rear bumpers and rocker mouldings. Examples of vehicle window materials include windscreens.

[0064] <Sealant>The sealant may be a member capable of imparting the adherend with properties such as sealing properties, waterproofing properties and adhesive properties. The sealant may have, for example, a layered or film-like shape. In addition, the sealant may have a thickness of 0.1 mm to 50 mm.

[0065] The sealant contains at least a polymer. In one embodiment, the sealant contains a polyurethane and / or a polyurea. For details of this polymer, see the statements above.

[0066] The sealant may be a member obtained by curing a sealant composition containing a polyurethane and / or a polyurea.

[0067] The sealant preferably includes a moisture-curable polyurethane.

[0068] In one embodiment, the sealant contains: a polyurethane and / or a polyurea; and a dicarbonyl compound. For details of the polyurethane and / or polyurea and the dicarbonyl compound, see the statements above. In this case, because the integrity and / or adhesive properties of the sealant are heat-dependently reduced, debonding is possible when necessary, and the sealant can be separated and removed from the adherend relatively easily.

[0069] The sealant may contain a solvent. The solvent may be lost through volatilisation during the layered product production process, but can remain in a finished layered product in some cases. The solvent may be a well-known solvent, examples of which include ethyl acetate and butyl acetate.

[0070] In a case where a dicarbonyl compound is contained, the sealant may have the following composition, for example:- 0-80 vol%, 0-50 vol% or 10-50 vol% of a polyurethane and / or polyurea- 0.1 -80 vol% of a dicarbonyl compound- 0-30 vol% or 0-15 vol% of a solvent

[0071] The sealant can, if necessary, also contain additives as long as the purpose and advantageous effect of the present invention are not impaired. Examples of additives include fillers, pigments, anti -blocking agents, dispersion stabilisers, thixotropic agents, viscosity modifiers, levelling agents, anti-gelling agents, photostabilisers, anti-aging agents, antioxidants, ultraviolet radiation absorbers, plasticisers, lubricants, anti-static agents, reinforcing materials, flame retardants, catalysts, anti-foaming agents, thickening agents, dispersing agents and organic solvents.

[0072] <Primer>The primer may be a member that has the function of improving adhesion between the adherend and the sealant. The primer may have, for example, a layered or film-like shape. In addition, the primer may have a thickness of 1 pm to 500 pm.

[0073] The primer may contain similar components to the sealant, and may contain, for example, the same type of polyurethane and / or polyurea as the sealant.

[0074] The primer may be a layered member obtained by applying (and especially coating) the primer composition on the adherend.

[0075] In one embodiment, the primer contains a polyurethane and / or a polyurea. For details of said polymers, see the statements above.

[0076] In a preferred embodiment, the primer contains a polyurethane and / or a polyurea, and also contains a dicarbonyl compound. For details of the polyurethane and / or polyureaand the dicarbonyl compound, see the statements above. In this case, by ensuring that the polyurethane and / or polyurea contained in the primer is decomposed by carrying out a heat treatment, it is possible to weaken the integrity of the primer and / or the adhesive strength of the primer to the adherend, and debonding by means of the heat treatment is possible when necessary. Therefore, according to this embodiment, it is possible to avoid or inhibit the sealant and / or the primer from remaining on the adherend, and even if the sealant and / or the primer do remain, these can be removed relatively easily, and the sealant and also the primer can be peeled from the adherend relatively neatly. A thus obtained adherend has a relatively clean surface following processing, and can therefore be reused and so on.

[0077] In a case where a dicarbonyl compound is contained, the primer may have the following composition, for example:- 1-80 vol% or 1 -20 vol% of a polyurethane and / or polyurea- 0.1 -80 vol% of a dicarbonyl compound- 0-95 vol%, 0-50 vol% or 0-5 vol% of a solvent

[0078] In a case where a dicarbonyl compound is not contained, the primer may have the following composition, for example:- 1-99 vol% or 50-99 vol% of a polyurethane and / or polyurea- 0-5 vol% or 0-1 vol% of a solvent

[0079] The primer may contain a solvent. The solvent may be lost through volatilisation during the layered product production process, but can remain in a finished layered product in some cases. Examples of solvents include ethyl acetate, butyl acetate and toluene. Of these, ethyl acetate and butyl acetate are preferred.

[0080] The primer can, if necessary, also contain additives as long as the purpose and advantageous effect of the present invention are not impaired. Examples of additives include fillers, pigments, anti -blocking agents, dispersion stabilisers, thixotropic agents, viscosity modifiers, levelling agents, anti-gelling agents, photostabilisers, anti-aging agents, antioxidants, ultraviolet radiation absorbers, plasticisers, lubricants, anti-static agents, reinforcing materials, flame retardants, catalysts, anti-foaming agents, thickening agents, dispersing agents and organic solvents.

[0081] <<Method for producing layered product>>The method for producing the layered product according to the present invention is not particularly limited. The layered product according to the present invention can be produced according to the following production method according to the present invention.

[0082] A method for producing a layered product which has an adherend, a sealant on the adherend, and a primer between the adherend and the sealant, wherein the method comprises:(a) providing an adherend (a provision step),(b) applying a primer composition to the adherend to form a primer layer (a primer application step),(c) applying a sealant composition to the primer layer (a sealant application step), and(d) curing the applied sealant composition to form a sealant (a curing step),andat least one of the sealant composition or the primer composition contains: a polyurethane and / or a polyurea; and a dicarbonyl compound.

[0083] For details of the method for producing a layered product according to the present invention (for example, constituent elements of the adherend, sealant, primer, dicarbonyl compound, and so on), see statements above relating to the layered productaccording to the present invention.

[0084] (Provision step)In the provision step, an adherend is provided. The surface of the layered product may be cleaned in advance. The cleaning can be carried out by, for example, wiping with an alcohol-impregnated wipe.

[0085] (Primer application step)In the primer application step, a primer composition is applied to the adherend to form a primer layer. The “application” may be carried out by, for example, “coating”.

[0086] For example, a brush, a roller, a sprayer, a rod, and so on, can be used as the application method. More specific examples of application methods include dip coating methods, coating methods involving a double roll coater, a slit coater, an air knife coater, a wire bar coater, a slide hopper, a spray coater, a blade coater, a doctor blade coater, a squeeze coater, a reverse roll coater, a transfer roll coater, an extrusion coater, a curtain coater, a dip coater, a die coater or a gravure roller, screen printing methods, dip coating methods, spray coating methods, spin coating methods and inkjet methods.

[0087] The applied primer composition may optionally be subjected to a drying treatment. The drying treatment may be carried out by leaving the primer composition for a period of 1 minute to 5 hours at room temperature or a temperature of 15°C to 35°C, or by air drying. For example, by drying the coated primer composition, it is possible to evaporate at least some of the solvent in the primer composition and form a film-like primer.

[0088] (Primer composition)

[0089] The primer composition contains at least a polyurethane and / or a polyurea. Preferably, the primer composition may be the primer composition according to the present invention, that is, the primer composition contains: a polyurethane and / or a polyurea; and a dicarbonyl compound. For details of the polyurethane, polyurea, polyisocyanate, polyol, polyamine and dicarbonyl compound, see the statements above.

[0090] The primer composition may also contain a solvent. Examples of solvents include ethyl acetate, butyl acetate and toluene. Of these, ethyl acetate and butyl acetate are preferred.

[0091] Use of a solvent is advantageous in terms of forming a thin uniform layer, but it is preferable for the amount of solvent in the primer composition to be as low as possible from the perspective of maintaining a suitable amount of polymer in the primer composition while further enhancing the debonding effect brought about by the dicarbonyl compound. In addition, replacing at least some of the solvent with a dicarbonyl compound that is a liquid at room temperature has been considered. In such a case, because the content ratio of the polymer (and also the dicarbonyl compound) increases, it is possible to better achieve functions required of the primer composition (for example, sealing properties, waterproofing properties, adhesive properties, and so on) and achieve a superior debonding effect.

[0092] The primer composition may have the following composition, for example:- 1-80 vol% or 1 -20 vol% of a polyurethane and / or polyurea- 0.1 -80 vol% of a dicarbonyl compound- 0-95 vol%, 0-50 vol% or 0-5 vol% of a solvent

[0093] The primer composition of the present invention can, if necessary, also contain additives as long as the purpose and advantageous effect of the present invention are not impaired. Examples of additives include fillers, pigments, anti-blocking agents,dispersion stabilisers, thixotropic agents, viscosity modifiers, levelling agents, antigelling agents, photostabilisers, anti-aging agents, antioxidants, ultraviolet radiation absorbers, plasticisers, lubricants, anti-static agents, reinforcing materials, flame retardants, catalysts, anti-foaming agents, thickening agents, dispersing agents and organic solvents. The primer composition can contain, for example, activated carbon.

[0094] (Sealant application step)In the sealant application step, a sealant composition is applied to the primer. The “application” may be carried out by, for example, “coating”, or by “filling” in a space between members, such as filling in a joint in a building. Examples of application methods include methods similar to those described above in relation to the primer application step (for example, methods involving a brush, a roller, a sprayer or a rod).

[0095] The sealant composition contains at least a polyurethane and / or a polyurea. For details of the polyurethane, polyurea, polyisocyanate, polyol, polyamine and dicarbonyl compound, see the statements above.

[0096] In a case where a dicarbonyl compound is contained, the sealant composition may have the following composition, for example:- 0-80 vol%, 0-50 vol% or 10-50 vol% of a polyurethane and / or polyurea- 0.1 -80 vol% of a dicarbonyl compound- 0-30 vol% or 0-15 vol% of a solvent

[0097] (Curing step)In the curing step, the applied sealant composition is cured to form a sealant. Depending on components contained in the sealant composition, and so on, the curing treatment can be carried out, as appropriate, in accordance with well-known methods.

[0098] In one embodiment, the sealant contains a moisture-curable polyurethane. In this case, the sealant composition can be cured by bringing the sealant composition into contact with water (for example, moisture in air). This type of moisture curing can be carried out by, for example, leaving the sealant composition to stand for a period of 1 hour to 30 days (and especially 1 -10 days) under conditions of a temperature of 15°C to 30°C and a relative humidity of 30-60%.

[0099] (Additional steps)The method for producing a layered product according to the present invention may include additional steps. For example, an additional member may be disposed on a sealant in a layered product formed using steps (a) to (d) described above. The additional member is not particularly limited, and may be made from materials similar to those described above in relation to the adherend.

[0100] <<Embodiment using adhesive>>As described above, the advantageous effect of the present invention can also be achieved in an embodiment in which an “adhesive” is used instead of a “sealant”. The “adhesive” may have, for example, a similar composition to the “sealant” described above and similar preferred ranges for components. The following invention of an assembly is described as an embodiment using an adhesive.

[0101] <Assembly>The present invention includes the following invention of an assembly:An assembly which has a first adherend, an adhesive, and a second adherend, and in which the first adherend and the second adherend are joined to each other by the adhesive, whereinat least one of the adhesive or a primer used together with the adhesive contains: a polyurethane and / or a polyurea; and a dicarbonyl compound.For details and preferred ranges of constituent elements in this embodiment (for example, adherend, primer, polyurethane, polyurea, dicarbonyl compound, and so on), see statements above relating to the layered product and production method thereof according to the present invention.

[0103] The assembly according to the present invention can have a first adherend, an adhesive, and a second adherend. For example, an assembly can be formed by bonding the first adherend and the second adherend to each other using the adhesive.

[0104] (Adhesive)The adhesive may have a similar composition to the “sealant” described above and similar preferred ranges for components. The adhesive is not particularly limited as long as the first adherend and the second adherend can be bonded to each other.

[0105] In the assembly according to the present invention, at least one of the adhesive or the primer used together with the adhesive contains: a polyurethane and / or a polyurea; and a dicarbonyl compound. In a preferred embodiment, both the adhesive and the primer contain a polyurethane and / or a polyurea, and at least the primer contains a dicarbonyl compound.

[0106] In one embodiment, the adhesive and the primer are substantially enclosed on all sides by the first adherend and the second adherend. Because the adhesive and the primer are substantially shielded from the external environment by configuring in this way, volatilisation of components can be suppressed, and it is therefore possible to achieve the advantageous effect of maintaining a debonding effect over a long period of time.

[0107] The expression “substantially enclosed on all sides” can mean that, for example, the adhesive and the primer are substantially shielded from the external environment by being sandwiched between one main surface of the first adherend and one main surface of the second adherend and being substantially sealed.

[0108] The method for producing an assembly according to the present invention is not particularly limited, and an assembly can be produced using the following method, for example:A method for producing an assembly which has a first adherend, an adhesive and a second adherend, and in which the first adherend and the second adherend are joined to each other by the adhesive, the method comprising(a) providing a first adherend,(b) applying a primer composition to the first adherend to form a primer layer,(c) applying an adhesive to the primer layer,(d) arranging a second adherend on the applied adhesive,and(e) curing the applied adhesive,whereinat least one of the adhesive or the primer composition contains: a polyurethane and / or a polyurea and; a dicarbonyl compound.

[0109] For details of constituent elements and preferred ranges in the assembly and production method thereof according to the present invention, see statements above relating to the layered product and production method thereof according to the present invention .

[0110] <<Debonding method>>The present invention includes a debonding method. The term “debonding method” can mean a method for weakening adhesion between two members bonded to each other either directly or indirectly, or a method for separating these two members from each other.One embodiment of the debonding method according to the present invention is a method comprising heat-dependently debonding a sealant (and also a primer) from an adherend in a layered product having the adherend, the sealant on the adherend, and the primer between the adherend and the sealant or in an assembly having two adherends bonded to each other via the adhesive and the accompanying primer,wherein the layered product is heated for a period of 1 minute to 5 hours at a temperature of 100°C to 160°C,andthe primer contains: a polyurethane and / or a polyurea; and a dicarbonyl compound.

[0112] For details of the debonding method according to the present invention (for example, constituent elements of the adherend, sealant, primer, dicarbonyl compound, and so on), see statements above relating to the layered product and assembly according to the present invention.

[0113] According to the debonding method according to the present invention, a sealant or adhesive (and also a primer) can be heat-dependently debonded when necessary in a layered product having an adherend, the sealant and the primer disposed between the adherend and the sealant or in an assembly having two adherends bonded to each other via the adhesive and the accompanying primer. Specifically, by bringing about heatdependent decomposition of a polymer by using a dicarbonyl compound contained in the primer, it is possible to weaken the integrity of the primer and / or weaken the adhesive strength of the primer to the adherend, thereby enabling the sealant or adhesive (and also the primer) to be removed (separated, peeled, and so on) from the adherend more easily.

[0114] The layered product may be heat treated using a well-known method, such as by using a heating furnace for example, or by heating the back surface of the adherend through contact with an electric heater (for example, a hotplate). The heat treatment temperature may be 100-160°C, 1 10-150°C, or 120-150°C. The heat treatment duration may be 10 seconds to 1 hour, 20 seconds to 45 minutes, 30 seconds to 30 minutes, or 1 minute to 20 minutes.

[0115] «Usage method>>The present invention also includes a method for using a dicarbonyl compound. One embodiment of the usage method is use of a dicarbonyl compound for heat-dependently debonding a sealant or an adhesive and / or a primer which contain a polyurethane and / or a polyurea and are bonded to an adherend.

[0116] For details of the usage method according to the present invention (for example, constituent elements of the adherend, sealant, primer, dicarbonyl compound, and so on), see statements above relating to the layered product and assembly according to the present invention.

[0117] In a case where a polyurethane and / or a polyurea are contained in a layered product having an adherend, a sealant and a primer disposed between the adherend and the sealant or in an assembly having two adherends bonded to each other via an adhesive and an accompanying primer, as described above, use of a dicarbonyl compound enables the sealant or adhesive (and also the primer) to be heat-dependently debonded when necessary.

[0118] In one embodiment of the usage method according to the present invention, a primer is disposed between an adherend and a sealant or an adhesive, the sealant or adhesive contains a polyurethane and / or a polyurea, and the primer contains: a polyurethane and / or a polyurea; and a dicarbonyl compound. At the interface between the sealant or adhesive and the primer, it is thought that the respective components of the sealant or adhesive and the primer at least partially mix with each other. Therefore, according tothis embodiment, at the interface between the sealant or adhesive and the primer, it is thought that the polyurethane and / or polyurea contained in the sealant or adhesive are heat-dependently decomposed by the dicarbonyl compound in the primer, thereby weakening the adhesive strength of the sealant or adhesive. Furthermore, it is thought that because the polyurethane and / or polyurea contained in the primer are also heat-dependently decomposed, the integrity of the primer per se and / or the adhesive strength of the primer to the adherend are also weakened, thereby further weakening adhesion of the sealant or adhesive to the adherend.

[0119] Therefore, according to this embodiment, it is possible to avoid or inhibit the sealant or the adhesive and / or primer from remaining on the adherend, and even if the sealant or the adhesive and / or primer do remain, these can be removed relatively easily, and the sealant or the adhesive and also the primer can be peeled from the adherend relatively neatly. A thus obtained “adherend” has a relatively clean surface following processing, and can therefore be reused and so on.

[0120] <<Intended uses>>The layered product, method for producing a layered product, primer composition and usage method according to the present invention can be used in, for example, construction materials, vehicle components (for example, motor vehicle components), and so on.

[0121] In addition, the debonding method according to the present invention can be used for, for example, disintegrating construction materials and vehicles (for example, motor vehicle components and so on) and for recovering materials for recycling.[Working Examples]

[0122] <<Working Example 1 and Comparative Examples l -3»Layered products were produced by bonding a sealant on a glass substrate serving as an adherend, with a primer interposed therebetween, and the “debonding-on-demand” of the layered products was evaluated.

[0123] <Working Example 1>(Production of layered product)The surface of a glass substrate serving as an adherend was wiped with a dust-free wipe and 2-propanol, and then left for 60 minutes. Next, a primer composition containing “Hamatite MS-90” (“GP”) and acetylacetone (“ACAC”) as a dicarbonyl compound at a volume ratio of 50:50 was coated on the surface of the glass substrate using a No. 28 rod coater, and left to stand at room temperature for 60 minutes without ventilation to form a primer on the glass substrate. Next, a sealant composition (MDI / IPDI-based high viscosity polyurethane; one -component type polyurethane (PU)) was applied to the formed primer in the form of three linear shapes (bead-like shapes) using 10 mm diameter nozzles. Next, a curing treatment was carried out for 7 days at a temperature of 23°C and a relative humidity of 50% to form a sealant and obtain a layered product according to Working Example 1.

[0124] The composition of Hamatite MS-90 (“GP”) is as follows:- polyurethane 25 vol%- ethyl acetate 70 vol%- activated carbon 5 vol%

[0125] (Evaluation of adhesive properties)Adhesive properties test (first test S I): the layered product of Working Example 1 was subjected to an adhesive properties test (a first test) at a temperature of 23°C and a relative humidity of 50%. Specifically, the adherend was fixed to a test table using a vice or a clamp, a slit was made with a knife at one end of the bead-like sealant so as tomake one end easier to lift, a tensile force was applied using pliers at a direction of 135° while holding the cut part to facilitate peeling, and the sealant was peeled from the surface of the adherend. The peeling speed was approximately 10 cm / min. When the pulling operation did not bring about peeling, a knife was applied to the stretched part to facilitate breakage (rupture) of the sealing material. The surface of the peeled adherend was observed, and the areas of the peeled part, the broken part of the sealing material and the broken part of the primer were compared and evaluated. The results are shown in Table 1 .

[0126] Adhesive properties test (second test S2): after carrying out the first adhesive properties test, the layered product was left to stand for 4 hours at 140°C, after which the sealant was peeled from the adherend at a direction of 135° in the same way as described above at a temperature of 23°C and relative humidity of 50%, and the surface of the adherend was observed following the peeling. The results are shown in Table 1.

[0127] Adhesive properties test (third test S3): after carrying out the second adhesive properties test, the layered product was left to stand for 1 hour at 23°C, after which the sealant was peeled from the adherend at a direction of 135° in the same way as described above while ventilating, and the surface of the adherend was observed following the peeling.

[0128] Evaluations in the adhesive properties tests were carried out according to the following criteria.“Residual sealant”: Some of the primer and sealant remained on the adherend (cohesive failure “CF” occurred).“Residual primer”: Primer remained on the adherend, and foamy disintegration was not observed (interfacial failure “AF” occurred).“Primer breakage”: Primer remained on the adherend, and foamy disintegration was observed (primer breakage “PB” occurred).

[0129] Components and evaluation results are shown in Table 1 and FIG. 2. FIG. 2 is a photograph that shows results of adhesion tests according to Working Example 1 (first test: S I, second test: S2, third test: S3).

[0130] <Comparative Example 1>A layered product was produced and evaluated in the same way as in Working Example 1, except that the GP : ACAC volume ratio in the primer was 100: 0 (ACAC was not contained). The results are shown in Table 1 and FIG. 2. FIG. 3 is a photograph that shows results of adhesion tests according to Comparative Example 1 (first test: S I, second test: S2, third test: S3).

[0131] <Comparative Example 2>A layered product was produced and evaluated in the same way as in Working Example 1, except that the GP : ACAC volume ratio in the primer was 0: 100 (GP was not contained). The results are shown in Table 1.

[0132] <Comparative Example 3>A layered product was produced and evaluated in the same way as in Working Example 1, except that the primer was not used, and the sealant was applied directly to the adherend. The results are shown in Table 1.

[0133] [Table 1]GP: glass primer, PU: polyurethane, ACAC: acetylacetone

[0134] The “Adhesive properties” category in table 1 is an evaluation category relating to primer performance, and a case where sealant adhesive properties were improved in comparison with a case where a primer was not used (Comparative Example 3) was evaluated as “O”, and a case where sealant adhesive properties were not thus improved was evaluated as “x” (the same applies in Tables 2 and 3).

[0135] As can be seen from Table 1 and FIGS. 2-3, in the layered product of Working Example 1, in which the primer contained a dicarbonyl compound (acetylacetone; ACAC), the primer did not break and remained on the adherend in the peeling test at room temperature (the first test) (see S I in FIG. 1), but in a case where peeling was carried out after a heat treatment at 140°C (the second test) and a case where a subsequent cooling period was provided (the third test), “primer breakage” was observed, in which some of the primer was deformed in a foam-like state (see S2 and S3 in FIG. 2). This shows that heat-dependent debonding occurred. Such an occurrence was not observed in the comparative examples (see Table 1 and S I to S3 in FIG. 3).

[0136] <<Working Example 2 and Comparative Examples 4-5>>Layered products according to Working Example 2 and Comparative Examples 4-5 were produced at component content values shown in Table 2 and evaluated in the same way as in Working Example 1, except that methyl acetoacetate (MAA) was used instead of acetylacetone (ACAC). The results are shown in Table 2.

[0137] [Table 2]GP: glass primer, PU: polyurethane, ACAC: acetylacetone, MAA: methyl acetoacetate

[0138] As can be seen from Table 2, heat-dependent “primer breakage” was observed in cases where methyl acetoacetate (MAA) was used instead of acetylacetone as a dicarbonyl compound.

[0139] <<Working Examples 3-4 and Comparative Examples 7 -9»Layered products of Working Examples 3 -4 and Comparative Examples 7-9 wereproduced and evaluated in the same way as in Working Example 1, except that thevolume ratio of GDP and ACAC in the primer were altered as shown in Table 3 below.Results are shown in Table 3. Table 3 shows that in the second test, 140°C was a trigger for invoking heat-dependent debonding. Table 3 shows that exposure to roomtemperature following the cooling in the third test was carried out in order to confirmthat the sealing layer had not merely melted, softened or peeled as a result of heating.

[0140] [Table 3]GP: glass primer, PU: polyurethane, ACAC: acetylacetone

[0141] As can be seen from Table 3, heat-dependent “primer breakage” was observed in cases where the content of acetylacetone serving as a dicarbonyl compound was altered.

Claims

Claims

1. A layered product which has an adherend, a sealant on the adherend, and a primer between the adherend and the sealant, whereinat least one of the sealant or the primer contains: a polyurethane and / or a polyurea; and a dicarbonyl compound, andwherein the dicarbonyl compound is in an amount of 12 % by volume to 90 % by volume, with respect to a total of the polyurethane and the polyurea and the dicarbonyl compound.

2. A primer composition comprising a polyurethane and / or a polyurea; and a dicarbonyl compound, wherein the dicarbonyl compound is contained in an amount of 12 % by volume to 90 % by volume, with respect to a total of the polyurethane and the polyurea and the dicarbonyl compound.

3. Method for producing a layered product,wherein the layered product has an adherend, a sealant on the adherend, and a primer between the adherend and the sealant, the method comprises(a) providing an adherend,(b) applying a primer composition to the adherend to form a primer layer,(c) applying a sealant composition to the primer layer, and(d) curing the applied sealant composition to form a sealant,andat least one of the sealant composition or the primer composition comprises: a polyurethane and / or a polyurea; and a dicarbonyl compound, andwherein the dicarbonyl compound is contained in an amount of 12 % by volume to 90 % by volume, with respect to a total of polyurethane and the polyurea and the dicarbonyl compound.

4. An assembly which has a first adherend, an adhesive, and a second adherend, and in which the first adherend and the second adherend are joined to each other by the adhesive,wherein at least one of the adhesive or a primer used together with the adhesive comprises: a polyurethane and / or a polyurea; and a dicarbonyl compound.

5. A method for thermally debonding a sealant or an adhesive from an adherend in a layered product or in an assembly,wherein the layered product comprises an adherend, a sealant on the adherend and a primer between the adherend and the sealant, and at least one of the sealant and the primer comprises : polyurethane and / or polyurea; and a dicarbonyl compound,wherein the assembly comprises a first adherend, an adhesive and a second adherend, the first adherend and the second adherend are bonded together by the adhesive, and at least one of the adhesive and a primer used in conjunction with the adhesive comprises: polyurethane and / or polyurea; and a dicarbonyl compound,and wherein the method comprises heating the layered product or the assembly at a temperature of 100°C to 160°C.

6. A use of a dicarbonyl compound for thermally debonding a sealant or an adhesive and / or a primer comprising: polyurethane and / or polyurea; and adhered to an adherend, wherein the use comprises heating the sealant or the adhesive and / or the primer comprising the dicarbonyl compound at a temperature of 100°C to 160°C.

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