Microcapsules and their use in polymers

Abstract

A plurality of microcapsules having a crosslinked polymer shell encapsulating an active ingredient, wherein the crosslinked polymer shell comprises or consists of at least one polymer selected from aliphatic epoxidized polyacrylates, such as soybean oil acrylate, bisphenol A-based epoxy acrylate, glyceryl propoxy triacrylate, difunctional polyester acrylate oligomers, aliphatic polyester-based urethane dimethacrylates or diacrylates, and amine-modified polyether acrylates. When a dispersion of the plurality of microcapsules in an inert medium is subjected to a shear stress of 3 kPa or more at a temperature of about 20°C, the dispersion has a mechanical resistance such that after being subjected to the shear stress for 10 minutes, the proportion of capsules broken as observed by microscope is less than 10%.

Description

[Technical Field]

[0001] This patent application claims priority to French provisional patent application FR2214023, filed December 20, 2022, the entire contents of which are incorporated by reference into this patent application for all purposes.

[0002] The present invention relates to a plurality of microcapsules that are mechanically resistant and particularly useful for improving the processability and properties of polymers. The present invention also relates to the use of a plurality of microcapsules in polymer processing, a premix comprising a polymer and a plurality of microcapsules, and a polymer composition comprising a plurality of microcapsules. [Background technology]

[0003] Encapsulation of active ingredients has been developed as a technological option to protect such active ingredients from unwanted and premature interactions with other components of the formulation or reaction mixture. Encapsulation is useful, for example, for providing cosmetic, pharmaceutical and agrochemical formulations in particular with improved efficiency of use of the active ingredient and reaction mixture, for example, of a polymerization mixture or a polymer processing mixture, and allows for improved processes and end products due to better controlled use of active ingredients, such as catalysts. WO-A-2018 / 172431 in the name of the applicant discloses a series of microcapsules with a polymer shell having a pore size of less than 1 nm, which are generally suitable for such purposes.

[0004] EP-A-2360221 relates to thermally expandable microcapsules comprising a polymeric shell and a volatile swelling agent encapsulated in the shell as a core agent, the shell having a storage modulus (E') of 1 x 10 N / m or more at 200°C and a frequency of 10 Hz, a storage modulus (E') of 1 x 10 N / m or more at 250°C and a frequency of 10 Hz, and a maximum displacement measured by thermomechanical analysis of 300 μm or more. The modulus is measured not on the capsule itself, but on test specimens having a thickness of 0.2 mm (200 μm), which is greater than the diameter of the particular microcapsule, as the microcapsules do not have a wall thickness suitable for delivering an active ingredient. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] WO-A-2018 / 172431 [Patent Document 2] EP-A-2360221 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention makes available further improved microcapsules which allow particularly advantageous use in polymer processing steps involving high shear stresses, which are particularly advantageous from the standpoint of mechanical stability. [Means for solving the problem]

[0007] In a first aspect, the present invention therefore relates to a plurality of microcapsules having a crosslinked polymeric shell encapsulating an active ingredient, the crosslinked polymeric shell comprising or consisting of at least one polymer selected from aliphatic epoxidized polyacrylates, such as soybean oil acrylate, bisphenol A-based epoxy acrylate, glyceryl propoxy triacrylate, difunctional polyester acrylate oligomers, aliphatic polyester-based urethane dimethacrylates or diacrylates, and amine-modified polyether acrylates.

[0008] In a first embodiment of the plurality of microcapsules according to the first aspect of the present invention, the crosslinked polymer shell comprises or consists of at least one polymer selected from aliphatic epoxidized polyacrylates, such as vegetable epoxidized oil acrylates, in particular soybean oil acrylate.

[0009] In a second embodiment of the microcapsules according to the first aspect of the present invention, the crosslinked polymer shell comprises or consists of at least one polymer selected from bisphenol A-based epoxy acrylates. Examples of suitable polymers according to this embodiment are selected from, for example, polymers of 4,4'-isopropylidenediphenol with 1-chloro-2,3-epoxypropane polypropylene glycol monoacrylate and succinic anhydride; polymers of 2-propenoic acid, 2-hydroxyethyl ester with (chloromethyl)oxirane, 1,3-isobenofurandione, 4,4'-(1-methylethylidene)bis[phenol] and 2-oxepanone; and polymers of 4,4'-(1-methylethylidene)bisphenol with (chloromethyl)oxirane, dodecanoate, 2-propenoate.

[0010] In a third embodiment of the plurality of microcapsules according to the first aspect of the present invention, the crosslinked polymer shell preferably comprises or consists of at least one polymer selected from glyceryl propoxy triacrylate.

[0011] In a fourth embodiment of the plurality of microcapsules according to the first aspect of the present invention, the crosslinked polymer shell preferably comprises or consists of at least one polymer selected from difunctional polyester acrylate oligomers. Examples of suitable polymers according to this embodiment are selected from, for example, polymers of propylidine trimethanol, ethoxylated esters of acrylic acid, and polymers of 2-[[2,2-bis[[(1-oxoallyl)methyl]butoxymethyl]-2-ethyl-1,3-propanediyl diacrylate.

[0012] In a fifth embodiment of the microcapsules according to the first aspect of the present invention, the crosslinked polymer shell preferably comprises or consists of at least one polymer selected from aliphatic polyester-based urethane dimethacrylates or diacrylates. Examples of suitable polymers according to this embodiment include, for example, polymers of 2-propenoic acid, 2-hydroxyethyl ester with 1,1-methylenebis[4-isocyanatocyclohexane] and α,α-1,2,3-propanetriyltris[ω-hydroxypoly[oxy(methyl-1,2-ethanediyl)]]; 7,7,9-trimethyl-3,14-dioxa-4,13-dioxo-5,12-diazahexadecane- The polymer is selected from the polymers of the reaction product of 1,16-diyl-prop-2-enoate with 7,7,9-trimethyl-3,14-dioxa-4,13-dioxo-5,12-diazahexadecane-1,16-diyl-prop-2-enoate and the polymers of 7,7,9-trimethyl-4,13-dioxo-3,14-dioxa-5,12-diazahexadecane-1,16-diylbis-methacrylate.

[0013] In a sixth embodiment of the plurality of microcapsules according to the first aspect of the present invention, the crosslinked polymer shell preferably comprises or consists of at least one polymer selected from amine-modified polyether acrylates. Examples of suitable polymers according to this embodiment are selected from, for example, polymers of 2-aminoethanol, α-hydro-ω-[(1-oxo-2-propenyl)oxy]poly(oxy-1,2-ethanediyl)ether with 2-ethyl-2-(hydroxymethyl)-1,3-propanediol.

[0014] In one particular embodiment of the first aspect of the present invention, the crosslinked polymer shell comprises 50% to 80% by weight of said at least one polymer, based on the total weight of the crosslinked polymer shell.

[0015] In a second aspect, the present invention relates to a plurality of microcapsules having a crosslinked polymer shell, the plurality of microcapsules having a mechanical resistance such that when a dispersion of the plurality of microcapsules in an inert medium is subjected to a shear stress of 3 kPa or more at a temperature of about 20° C., the proportion of broken capsules observed under a microscope after the dispersion is subjected to said shear stress for 10 minutes is less than 10%. In a preferred aspect, the proportion of broken capsules is 5% or less. The proportion of broken capsules may be about 0%, but is often greater than 0%, e.g., 1% or more.

[0016] Unless otherwise stated, the following specification applies to both the first and second aspects of the invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] The microcapsules according to the present invention remain substantially intact under high mechanical stress conditions, making them particularly advantageous for, for example, targeted release of active ingredients. They also have particularly advantageous storage and transport properties, as microcapsule breakage and associated degradation of the microcapsules can be substantially avoided. A further advantage of the microcapsules is their ability to remain present and thereby protect the active ingredient during industrial processing and shaping of polymers, for example, by techniques such as injection molding and / or extrusion. The microcapsules can then release the required active ingredient upon intentional exposure to a stimulus, such as a change in temperature, without loss of reactive components prior to exposure. The microcapsules according to the present invention may have high resistance when subjected to various types of mechanical stress, such as shear stress and compressive stress.

[0018] The microcapsules according to the present invention may have high mechanical resistance even under high shear stress. For example, the shear stress may be 6 kPa or more, particularly 9 kPa or more. The shear stress generally does not exceed 1 MPa, particularly 30 kPa or less. In industrial processes for capsule-containing resins, the shear stress can reach up to 50 MPa. Therefore, as known to those skilled in the art, in a three-roll mill system, the shear stress can be adjusted to approximate these conditions by controlling the viscosity of the medium, the spacing between the mills, and the rotation speed. Under these conditions, the capsules remain largely intact, as explained below.

[0019] The mechanical resistance of the microcapsules is preferably measured by method (1) described below.

[0020] The temperature during the measurements is maintained at about 20° C. "About 20° C." is understood in particular to mean that the temperature is maintained between 17° C. and 23° C., in particular between 18° C. and 22° C. It has been observed that variations in this temperature range during the measurements do not affect the proportion of ruptured microcapsules.

[0021] For the purposes of the present invention, "broken microcapsules" refers to microcapsules whose shells have visible perforations when viewed under an optical microscope equipped with a 100x objective. By way of example, a DMi8 microscope (Leica) equipped with an HCX Plan Apo 100x / 1.4-0.7 objective and operating in transmitted light mode can be used to evaluate a group of such capsules.

[0022] For the purposes of the present invention, "inert medium" refers to a generally liquid medium that does not exhibit chemical reactivity with the crosslinked polymer shell under conditions of mechanical resistance determination, including microscopic observation. The inert medium usually has an optical transparency of more than 80%, as defined, for example, by ASTM standard D1746.

[0023] The inert medium is preferably -1 ~2000s -1 The viscosity of the inert medium is 400 cPa-s or more and 1500 cPa-s or less. -1 ~2000s -1 Within the shear range of 100°C, the tensile strength exhibits negligible variation, i.e., <10%, preferably <5%, and most preferably <2%.

[0024] An example of a suitable inert medium is an aqueous solution of carboxymethyl cellulose. Another example of a suitable inert medium is selected from silicones.

[0025] For the purposes of the present invention, the term "mean diameter or average of the microcapsules" refers to the Dn50 diameter. Dn50 is the median of the number-average size distribution of the microcapsules. The size distribution of the microcapsules, and therefore the mean diameter of the microcapsules, may be measured by methods well known to those skilled in the art, for example by light scattering techniques such as a Mastersizer 3000 equipped with a hydroSV measuring cell, or by image analysis of optical micrographs or by image analysis of electron micrographs.

[0026] For the purposes of the present invention, "monodisperse" is understood to mean that for a series of droplets or a series of capsules, the standard deviation of the distribution of the diameters of the droplets or capsules is less than 50%, in particular less than 25%, or less than 1 μm. For the purposes of the present invention, the diameter of the droplets or capsules is determined by light scattering techniques using a Mastersizer 3000 (Malvern Instruments) equipped with a HydroSV measuring cell.

[0027] For the purposes of the present invention, "plurality" refers to a significant number of microcapsules, e.g., a quantity of microcapsules resulting from the synthesis of the microcapsules or a quantity of microcapsules suitable for the intended use of the microcapsules, particularly for industrial applications. For the purposes of determining the number of broken microcapsules in a series of microcapsules, a representative sample is used, as described below, containing at least 50 microcapsules, preferably at least 100 microcapsules.

[0028] For a given set of shear conditions, temperature, and duration of shear, the nature of the inert medium and the concentration of microcapsules in the dispersion have been observed to have no measurable effect on the percentage of ruptured capsules, although typically the concentration of microcapsules in the dispersion is between 10% and 25% by weight, based on the total weight of the dispersion.

[0029] In another embodiment of the present invention, the mechanical properties of a plurality of microcapsules are measured by nanoindentation. Nanoindentation is a method in which individual microcapsules are subjected to compressive stress through the application of an indenter, either a Berkovich (pyramid), a flat-punch indenter, or a spherical indenter. In the present invention, an Anton Paar NHT3 nanoindenter may be employed as an example. A suitable method for performing nanoindentation measurements may be described as follows: a hard tip with known mechanical properties, often made of an extremely hard material such as diamond, is pressed into a sample with unknown properties. The load applied to the indenter tip increases as the tip penetrates further into the specimen, up to a user-specified value. At this point, the load may be held constant for a period of time or removed. An indenter of known shape with high precision (usually a triangular pyramidal Berkovich tip) is used. During instrumented indentation, the penetration depth is recorded, and the contact area between the indenter and the microcapsules is then determined. During indentation, parameters such as load and depth of penetration can be measured using capacitive sensors. Records of these values ​​can be plotted on a graph to create a load-displacement curve and used to extract the mechanical properties of the material. The area of ​​the remaining indentation in the sample is measured through an optical microscope or a scanning electron microscope, which are standard components of nanoindentation equipment, and the hardness H is determined by the maximum load P. max is defined as the residual indentation area A, determined by in situ microscopic image analysis.

[0030] The breaking force, i.e., the force at which a large displacement of the indentation can be observed, indicates the force that the capsule can withstand before breaking. Usually, the large displacement is evidenced by an inflection point in the force / displacement curve. Therefore, another aspect of the present invention relates to a plurality of microcapsules having a mechanical resistance such that the breaking force for said capsule is greater than 100 μN, preferably greater than 300 μN, but generally not more than 1000 μN. The breaking force can be more generally described by the breaking stress, which is simply the breaking force divided by the surface area of ​​the indenter. For a diameter of 20 μm, therefore, 314 μm 2 In the case of a flat punch indenter having a dish-like shape with an area of ​​0.5 MPa, the breaking stress is greater than 0.5 MPa, and preferably greater than 1 MPa, most preferably greater than 3 MPa. The diameter of the flat punch indenter is, however, usually chosen to be equal to or greater than the diameter of the microcapsules to be analyzed.

[0031] Alternatively, the rupture stress is more optimally calculated using the contact surface area between the surface of the indenter and the surface of the microcapsule. The contact area in the sense of the present invention can be determined using the principle of volume conservation before rupture of the microcapsule. The microcapsules are observed under an optical microscope before being measured by nanoindentation. The capsule diameter is determined from a two-dimensional image of the microcapsule to be measured. The capsules are, on average, spherical before nanoindentation. Therefore, the capsule volume of a plurality of microcapsules according to the present invention is calculated as a sphere. The volume is conserved under compression, which induces deformation into an ellipsoid. For the purpose of determining the rupture stress of a plurality of microcapsules according to the present invention, the ellipsoid is considered as a rectangular prism, and its volume is given by the formula V = z × A, where V is the volume, z is the height of the deformed capsule, determined as the difference between the diameter d of the undeformed capsule and the displacement h measured by the nanoindenter, and A is the contact area. The volume of the rectangular prism is set equal to the volume of the capsule before compression.

[0032] Therefore, the contact area A is simply the capsule volume divided by the capsule height z, and the formula A=(4 / 3×π×(d / 2) 3 ) / z.

[0033] The contact area at break is determined based on the z value at the nonlinear point of the force versus displacement curve, a standard measurement in nanoindentation.

[0034] In another aspect, the invention relates to a plurality of microcapsules having a diameter of 1 to 30 μm and having a mechanical resistance such that when the plurality of microcapsules are subjected to a force of 3000 μN, the percentage of capsules broken does not exceed 10%, preferably the percentage of capsules broken is greater than 0% and not more than 5%, more preferably greater than 0% and not more than 1%.

[0035] In this embodiment, the mechanical resistance is generally such that when the plurality of microcapsules are subjected to a compressive stress of 1 MPa, the percentage of ruptured capsules does not exceed 10%, as determined by optical microscopy.

[0036] In yet another aspect, the present invention relates to a plurality of microcapsules having a monodisperse particle size distribution, a diameter of 1 to 30 μm, and a mechanical resistance such that when the plurality of microcapsules are subjected to a compressive stress of 1 to 3 MPa, the percentage of broken capsules, as determined by optical microscopy, as described above, does not exceed 10%, preferably does not exceed 5%, and most preferably does not exceed 1%. In this aspect, the percentage of broken capsules may be about 0%, but is often greater than 0%.

[0037] In a plurality of microcapsules according to the invention, the microcapsules generally have an average diameter of 1 μm or more, preferably 3 μm or more. In a plurality of microcapsules according to the invention, the microcapsules generally have an average diameter of 30 μm or less, preferably 20 μm or less.

[0038] In the microcapsules according to the present invention, the microcapsules generally have a shell thickness of 0.1 μm or more, preferably 0.2 μm or more. In the microcapsules according to the present invention, the microcapsules generally have a shell thickness of 20 μm or less, preferably 8 μm or less. Shell thickness, also referred to as wall thickness, refers to the thickness of the generally solid, cross-linked polymer membrane that surrounds the interior space of the microcapsule.

[0039] In a first particular embodiment of the plurality of microcapsules according to the invention, the microcapsules have an average diameter of between 1 and 30 μm and a wall thickness of between 0.1 and 20 μm.

[0040] Microcapsules according to the present invention are often monodisperse.

[0041] In a second particular embodiment of the plurality of microcapsules according to the invention, the microcapsules have an average diameter of between 1 μm and 30 μm, the thickness of the solid shell is between 0.2 μm and 8 μm, and the standard deviation of the distribution of the diameters of the microcapsules is less than 50%, or less than 1 μm.

[0042] The plurality of microcapsules may have pores on the shell surface of the microcapsules having an average diameter of less than 1 nm as determined by BET surface analysis.

[0043] In a preferred embodiment of the microcapsules according to the invention, the crosslinked polymer shell is obtained by photopolymerization of a photopolymerizable composition having reactive groups. In this embodiment, the conversion of the reactive groups of the photopolymerizable composition is generally at least 80%, preferably at least 90%.

[0044] The conversion of reactive groups can be determined by monitoring the disappearance of a band representative of the functional group in FTIR. The absorbance of an IR band is proportional to the amount of functional group, so a decrease in peak height corresponds to a decrease in the amount of functional group and, in turn, indicates successful polymerization. A standard method for doing this is to compare the FTIR absorbance of the emulsion before and after crosslinking, particularly by photopolymerization. For the purposes of the present invention, this can be done using the method described in Barszczewska-Rybarek, Materials 2019, 12(24), 4057. As an example, the conversion of acrylate reactive groups during radical polymerization can be observed as a function of the decrease in the FTIR absorbance of its characteristic spectrum, which for acrylates corresponds to wavelengths between 2900 μm and 3000 μm.

[0045] Consequently, the present invention also relates to microcapsules having a crosslinked polymer shell encapsulating an active ingredient, wherein the crosslinked polymer shell has a conversion of 80% or more, preferably 90% or more, as determined by observing a decrease in FTIR absorption of the characteristic FTIR absorption band of the crosslinkable precursor group of the crosslinked polymer shell. Generally, the conversion is less than 100%, particularly less than 95%. When crosslinking is carried out by photopolymerization, the degree of crosslinking corresponds to the conversion of the polymerizable group.

[0046] According to the invention, in particular in its first aspect, the crosslinkable precursor groups are preferably chosen from acrylates and methacrylates.

[0047] Without wishing to be bound by any theory, the degree of cross-linking provides advantages in terms of mechanical stability and retention capacity of the microcapsules.

[0048] In a preferred embodiment, the plurality of microcapsules characterized by the degree of cross-linking is in accordance with the plurality of microcapsules according to the invention described herein.

[0049] In a second embodiment of the microcapsules according to the invention, the crosslinked polymer shell often comprises or consists of at least one polymer selected from polyethers, polyesters, polyurethanes, polyureas, polyethylene glycols, polypropylene glycols, polyamides, polyacetals, polyimides, polyolefins, polysulfides and polydimethylsiloxanes, said polymer having at least one reactive group selected from the group consisting of acrylates; methacrylates; vinyl ethers; N-vinyl ethers; mercaptoesters; thiolenes; siloxanes; epoxies; oxetanes; urethanes; isocyanates; and peroxides.

[0050] The term "crosslinker" is used to mean a compound having at least two reactive functional groups capable of crosslinking a monomer or polymer, or a mixture of monomers or polymers, during its polymerization.

[0051] In the second embodiment of the microcapsules according to the present invention, examples of specific polymers that may be used to prepare the crosslinked shell include, but are not limited to, the following polymers: poly(2-(1-naphthyloxy)-ethyl acrylate), poly(2-(2-naphthyloxy)-ethyl acrylate), poly(2-(2-naphthyloxy)-ethyl methacrylate), polysorbitol dimethacrylate, polyacrylamide, poly((2-(1-naphthyloxy)ethanol), poly(2-(2-naphthyloxy)ethanol), poly(1-chloro-2),3-epoxypropane), poly(n-butyl isocyanate), poly(N-vinylcarbazole), poly(N- vinylpyrrolidone), poly(p-20 benzamide), poly(p-chlorostyrene), poly(p-methylstyrene), poly(p-phenylene oxide), poly(p-phenylene sulfide), poly(N-(methacryloxyethyl)-succinimide), polybenzimidazole, polybutadiene, polybutylene terephthalate, polychloral, polychlorinated trifluoroethylene, polyetherimide, polyetherketone, polyethersulfone, polyhydridosilsesquioxane, poly(m-phenyleneisophthalamide), poly(methyl-2-acrylamido-2-methoxyacetate), poly(2-acrylamide-25) 2-Methylpropanesulfonic acid), poly-mono-butyl maleate, polybutyl methacrylate, poly(N-tert-butyl methacrylamide), poly(N-butyl methacrylamide), polycyclohexyl methacrylamide, poly(N-xylenebisacrylamide-2,3-dimethyl-1,3-butadiene, N,N-dimethyl methacrylamide), poly(n-butyl methacrylate), poly(cyclohexyl methacrylate), polyisobutyl methacrylate, poly(4-cyclohexylstyrene), polycycloacrylate, polycyclomethacrylate, polydiethyl 30 ethoxymethylene malonate, poly(2,2,2-trifluoroethyl methacrylate), poly(1,1,1-trimethylolpropane trimethacrylate), polymethacrylate, poly(N,N-dimethylaniline,Dihydrazide), Poly(Isophthalic Dihydrazine), Isophthalic Polyacid, Polydimethylbenzyl Ketal, Epichlorohydrin, Poly(ethyl-3,3-diethoxyacrylate), Poly(ethyl-3,3-dimethylacrylate), Poly(ethyl vinyl ketone), Poly(vinyl ethyl ketone), Poly(pentan-3-one), Polyformaldehyde Poly(diallyl acetal), Polyfumaronitrile, Polyglycerylpropoxytriacrylate, Polyglyceryltrimethacrylate, Polyglycidoxypropyltrimethylsilane Trimethoxysilane, polyglycidyl acrylate, poly(n-heptyl acrylate), poly(n-heptyl acrylate), poly(n-heptyl methacrylate), poly(3-hydroxypropionitrile), poly(2-hydroxypropyl acrylate), poly(2-hydroxypropyl methacrylate), poly(N-(5-methacryloxyethyl)phthalimide), poly(1,9-nonanediol diacrylate), poly(1,9-nonanediol dimethacrylate), poly(N-(n-propyl)acrylate) amide), poly(orthophthalic acid), poly(isophthalic acid), poly(1,4-benzenedicarboxylic acid), poly(1,3-benzenedicarboxylic acid), poly(phthalic acid), poly(mono-2-acryloxyethyl ester), terephthalic polyacid, polyphthalic anhydride, polyethylene glycol diacrylate, polyethylene glycol methacrylate, polyethylene glycol dimethacrylate, polyisopropyl acrylate, polysorbitol pentaacrylate, polyvinyl bromoacetate, polychloroprene, poly (di-n-hexylsilylene), poly(di-n-propylsiloxane), polydimethylsilylene, polydiphenylsiloxane, polyvinyl propionate, polyvinyltriacetoxysilane, polyvinyltris-tert-butoxysilane, polyvinyl butyral, polyvinyl alcohol, polyvinyl acetate, polyethylene co-vinyl acetate, poly(bisphenol-A15 polysulfone), poly(1,3-dioxepane), poly(1,3-dioxolane), poly(1,4-phenylenevinylene), poly(2,6-dimethyl-1A-phenylene oxide), poly(4-hydroxybenzoic acid), poly(4-methylpentene-1), poly(4-vinylpyridine), polymethylacrylonitrile, polymethylphenylsiloxane, polymethylsilmethylene, polymethylsilsesquioxane, poly(phenylsilsesquioxane), poly(pyromellitimide-1,4-diphenyl ether), polytetrahydrofuran, polythiophene, poly(trimethylene oxide), polyacrylonitrile, polyethersulfone, polyethylene-co-vinyl acetate, poly(perfluoroethylenepropylene), poly(perfluoroalkoxyalkane), or poly(styreneacrylonitrile).

[0052] Preferred examples of polymers that can be used to produce the crosslinked shell include aliphatic epoxidized polyacrylates such as soybean oil acrylate, bisphenol A-based epoxy acrylate, glyceryl propoxy triacrylate, difunctional polyester acrylate oligomers, aliphatic polyester-based urethane dimethacrylates or diacrylates, and amine-modified polyether acrylates, in which case the crosslinked shell comprises or consists of at least one of the foregoing polymers.

[0053] The crosslinker may be selected from molecules having at least two functional groups selected from the group consisting of acrylate, methacrylate, vinyl ether, N-vinyl ether, mercaptoester, thiolene, siloxane, epoxy, oxetane, urethane, isocyanate, and peroxide functional groups.

[0054] Examples of crosslinkers may include, inter alia: diacrylates, such as 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, polyethylene glycol dimethacrylate, 1,9-nonanediol dimethacrylate, 1,4-butanediol dimethacrylate, 2,2-bis(4-methacryloxyphenyl)propane, 1,3-butanediol dimethacrylate, 1,10-decanediol dimethacrylate, bis(2-methacryloxyethyl)N,N'-1,9 -Nonylene biscarbamate, 1,4-butanediol diacrylate, ethylene glycol diacrylate, 1,5-pentanediol dimethacrylate, 1,4-phenylenediacrylate, allyl methacrylate, N,N'-methylenebisacrylamide, 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane, tetraethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol Diacrylates, triethylene glycol dimethacrylate, polyethylene glycol diglycidyl ether, N,N-diallylacrylamide, 2,2-bis[4-2-acryloxyethoxy]phenyl]propane, glycidyl methacrylate; polyfunctional acrylates, such as dipentaerythritol pentaacrylate, 1,1,1-trimethylolpropane triacrylate, 1,1,1-trimethylolpropane trimethacrylate, ethylenediamine tetramethacrylate, pentaerythritol tetraacrylate triacrylate, pentaerythritol tetraacrylate; acrylates that also have other reactive functional groups, such as propargyl methacrylate, 2-cyanoethyl acrylate, tricyclodecane dimethanol diacrylate, hydroxypropyl methacrylate, N-acryloxysuccinimide, N-(2-hydroxypropyl)methacrylamide, N-(3-aminopropyl)methacrylamide hydrochloride, N(t-BOC-aminopropyl)methacrylamide, 2-aminoethyl methacrylate hydrochloride.Monoacryloxyethyl phosphate, o-nitrobenzyl methacrylate, acrylic anhydride, 2-(tert-butylamino)ethyl methacrylate, N,N-diallylacrylamide, glycidyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxybenzophenone, N-(phthalimidomethyl)acrylamide, cinnamyl methacrylate.

[0055] In certain embodiments, the above-described polymers can be used to produce the crosslinked shell in the second embodiment of the microcapsules according to the present invention, or can be used as an additional component of the crosslinked shell in the first embodiment of the microcapsules according to the present invention. In such cases, their content is generally less than 50% by weight, based on the total weight of the crosslinked polymer shell. In such cases, their content is generally 20% by weight or more, based on the total weight of the crosslinked polymer shell.

[0056] In a particular embodiment of the microcapsules according to the invention, the crosslinked polymer shell is essentially free of nitrile functional groups. "Essentially free of nitrile functional groups" is understood to mean, in particular, a content of nitrile functional groups of less than 1% by weight, preferably less than 0.5% by weight, relative to the total weight of the crosslinked polymer shell. This is especially true when nitriles are not used as monomers, polymers or crosslinkers for the production of the crosslinked polymer shell.

[0057] The reactive agent may be released through a specific external stimulus, including, but not limited to, a change in pH, exposure to ultraviolet radiation, a change in temperature, and / or combinations thereof. To achieve said release through an external stimulus, specific components of the shell may be selected, for example, as described in EP 3548529.

[0058] In the microcapsules according to the invention, the shell encapsulates an active ingredient. The active ingredient may be a solid at 25° C. The active ingredient may also be a liquid at 25° C. and a pressure of 1013.25 kPa.

[0059] A plurality of microcapsules according to this embodiment can be obtained, for example, preferably by a continuous process comprising the steps of: (a) preparing a double emulsion comprising droplets of at least one component (C1) dispersed in a photopolymerizable composition C2, said droplets being dispersed in a composition C3, and compositions C2 and C3 being immiscible with each other; (b) introducing a controlled shear rate into the double emulsion to prepare a mixed double emulsion (C4); and (c) irradiating the mixed double emulsion (C4) to prepare microcapsules.

[0060] In this embodiment, the active ingredient is often selected from catalysts, UV absorbers, lubricants and flame retardants, pigments and liquid crystal materials. Procedures for the preparation of double emulsions are described in the name of the applicant, inter alia, in EP 3548529, US-A-2020129948 and US-A-2021113984, the contents of which are incorporated by reference into the present patent application.

[0061] In the microcapsules according to the invention, the active ingredient may suitably be selected from the following, for example: crosslinkers, curing agents, organic or metallic catalysts (e.g. organometallic or non-organometallic complexes of platinum, palladium, titanium, molybdenum, copper, zinc) used in the formulation of polymers, elastomers, rubbers, paints, adhesives, sealants, mortars, varnishes or coatings to be polymerized;

[0062] Dyes or pigments intended for elastomer, paint, coating, adhesive, sealant, mortar, or paper formulations

[0063] Fragrances (according to the list of molecules established by the International Fragrance Association (IFRA) and available on the website www.ifraorg.org) for cleaning / laundry products, home care products, cosmetics and personal care products, fabrics, paints, coatings and other cleaning products;

[0064] Vitamins, amino acids, proteins, lipids, probiotics, antioxidants, pH regulators, preservatives, and other flavorings / flavorings for food compounds and animal feed;

[0065] Softeners, conditioning agents for detergent products, cleaning / laundry products, cosmetics and personal care products. In this regard, active ingredients that may be used are, for example, those listed in U.S. Patents US Pat. No. 6,335,315 and US Pat. No. 5,877,145;

[0066] Anti-discoloration or anti-fading agents (such as ammonium derivatives), anti-foaming agents (such as alcohol ethoxylates, alkylbenzene sulfonates, polyethylene ethoxylates, alkyl ethoxy sulfates, or alkyl sulfates) for detergents and cleaning / laundry products and home care products;

[0067] Brighteners, also referred to as color activators (such as stilbene derivatives, coumarin derivatives, pyrazoline derivatives, benzoxazole derivatives or naphthalimide derivatives), intended for detergents and cleaning / laundry products, cosmetics and home care products;

[0068] Biologically active compounds, such as enzymes, vitamins, proteins, plant extracts, softeners, disinfectants, antibacterial agents, anti-UV agents, pharmaceuticals, etc., for cosmetics and personal care products and fabrics, including: vitamins A, B, C, D, and E, para-aminobenzoic acid, alpha hydroxy acids (e.g., glycolic acid, lactic acid, malic acid, tartaric acid, or citric acid), camphor, ceramides, polyphenols (e.g., flavonoids, phenolic acids, ellagic acid, tocopherol, ubiquinol), hydroquinone, hyaluronic acid, isopropyl isostearate, isopropyl palmitate, oxybenzone, panthenol, proline, retinol, retinyl palmitate, salicylic acid, sorbic acid, sorbitol, triclosan, and tyrosine;

[0069] Bactericides, antibacterial agents, anti-UV agents for paints and coatings;

[0070] Agricultural chemical products such as fertilizers, herbicides, insecticides, pesticides, fungicides, insect repellents, or bactericides, including agricultural chemical products;

[0071] Fire-resistant agents, also known as flame retardants, for plastic materials, coatings, paints, and textiles (e.g., brominated polyols such as tetrabromobisphenol A, halogenated or non-halogenated organophosphorus compounds, chlorinated compounds, alumina trihydrate, antimony oxide, zinc borate, red phosphorus, melamine, or magnesium dihydroxide);

[0072] Photo-liquid crystals or photochromic agents intended for use in polymeric materials to form paints, coatings, and curved and flexible screens;

[0073] Products intended for energy storage, known to those skilled in the art by the colloquial name of phase change materials (PCM), are products that are capable of absorbing or releasing so-called "latent" heat when they change phase. Examples of PCMs and their applications are described in "A review on phase change energy storage: materials and applications", Farid et al., Energy Conversion and Management, 2004, 45(9-10), 1597-1615. Examples of PCMs may include aluminum phosphate, ammonium carbonate, ammonium chloride, cesium carbonate, cesium sulfate, calcium citrate, calcium chloride, calcium hydroxide, calcium oxide, calcium phosphate, calcium saccharate, calcium sulfate, cerium phosphate, iron phosphate, lithium carbonate, lithium sulfate, magnesium chloride, magnesium sulfate, manganese chloride, manganese nitrate, manganese sulfate, potassium acetate, potassium carbonate, potassium chloride, potassium phosphate, rubidium carbonate, rubidium sulfate, disodium tetraboronate, sodium acetate, sodium bicarbonate, sodium bisulfate, sodium citrate, sodium chloride, sodium hydroxide, sodium nitrate, sodium percarbonate, sodium persulfate, sodium phosphate, sodium propionate, sodium selenite, sodium silicate, sodium sulfate, sodium tellurite, sodium thiosulfate, strontium hydrogen phosphate, zinc acetate, zinc chloride, sodium thiosulfate, paraffinized hydrocarbon wax, molten salt of polyethylene glycol.

[0074] In one embodiment of the plurality of microcapsules according to the present invention, the active ingredient does not comprise a foaming agent. In this embodiment, the active ingredient often does not include a foaming agent. Generally, the microcapsules in this embodiment of the plurality of microcapsules according to the present invention are not expandable.

[0075] In certain embodiments of the preferred aspects of the microcapsules according to the present invention, the active ingredient is a lubricant. Examples of suitable lubricants include, but are not limited to, oils such as mineral oil, polyalphaolefins, polyglycols, synthetic esters, phosphate esters, triglyceride esters, polyol esters, fatty acids, vegetable oils, silicone oils, polyethers, perfluoropolyethers, and in particular amides such as erucamide or ethylene bis(stearamide), as well as solid lubricants such as synthetic or natural waxes (paraffins).

[0076] The multiple microcapsules of this particular embodiment have been found to be particularly advantageous for increasing the abrasion or scratch resistance or water resistance of polymer surfaces.

[0077] Therefore, the present invention also relates to the use of a plurality of microcapsules according to this particular embodiment to enhance the abrasion resistance or scratch resistance of a polymer surface, and to the use of a plurality of microcapsules according to this particular embodiment to enhance the water resistance of a polymer surface. Such polymer surfaces include, for example, epoxy resin surfaces or acrylic resin surfaces. Such surfaces may also be applied to objects such as, for example, coatings, fabrics, and gaskets.

[0078] Therefore, the present invention also relates to the use of a plurality of microcapsules according to this particular embodiment for the self-lubrication of elastomers.Preferably, the lubricant is a polyol ester.

[0079] The composition of elastomer and multiple microcapsules according to the present invention has been found to maintain storage and processing advantages while adequately releasing lubricant when exposed to high shear stress for extended periods of time.

[0080] The present invention also relates to the use of a plurality of microcapsules according to the invention for the delivery of an active ingredient to a polymerization process or a polymer processing process.

[0081] The microcapsules according to the present invention, and in particular preferred embodiments, have been found to be particularly advantageous in protecting active ingredients such as catalysts under the sometimes severe conditions of mechanical stress and temperature encountered. In embodiments where the microcapsules contain air or gas, the microcapsules allow for an effective and stable reduction in the density of the produced polymer.

[0082] The use according to the invention may be, for example, for the production of thermosetting polymers. It may be for the production of thermoplastic or thermosetting articles by molding, extrusion or casting. It may be for the production of thermoplastic or thermosetting articles by compression molding or injection molding.

[0083] The present invention also relates to a premix for producing a thermosetting polymer, comprising a plurality of microcapsules according to the present invention. The premix according to the present invention preferably comprises an epoxy resin combined with a plurality of microcapsules according to the present invention, which contain, as an active ingredient, an anionic or cationic catalyst. Another embodiment may be a premix in the form of an acrylic resin, a vinyl resin, or a polyester combined with a plurality of microcapsules according to the present invention, which contain, as an active ingredient, an unsaturated monomer diluent such as acrylic acid, acrylamide, acryloyl chloride, and methyl methacrylate.

[0084] In another embodiment, a premix according to the present invention comprises an isocyanate resin in combination with a plurality of microcapsules according to the present invention, which contain at least a polyol as an active ingredient.

[0085] The storage and processing stability of the premixes according to the invention has been found to be improved, being capable of surviving the extreme conditions to which the premixes may be subjected during standard processing conditions, such as extrusion and / or injection molding.

[0086] In a particular embodiment, a premix according to the present invention comprises an epoxy resin and a plurality of microcapsules according to the present invention, the active ingredient of which is a latent accelerator for curing the epoxy resin. Suitable latent accelerators may be selected, for example, from amine latent accelerators, particularly polyamine latent accelerators. A particular example is a modified polyamine, such as Ancamine 2014FG.

[0087] The present invention also relates to a mixture comprising a thermoplastic polymer and a plurality of microcapsules according to the present invention. Examples of thermoplastic polymers that can be used in the mixture according to the present invention include, but are not limited to, polyolefins such as polyethylene and polypropylene, polyvinyl chloride, polystyrene, polyamides, and polyesters.

[0088] The present invention also relates to a polymer composition comprising a plurality of microcapsules according to the present invention.

[0089] It is yet another object of the present invention to provide a method for determining the mechanical resistance of a plurality of microcapsules having a core and a polymeric shell, comprising the steps of: (a) preparing a dispersion of a plurality of microcapsules in an inert medium; (b) subjecting the dispersion to a determined shear stress at a specified temperature for a specified time; and (c) determining by optical analysis the percentage of capsules that have ruptured after step (b).

[0090] In the process according to the invention, the inert medium is generally a clear, viscous liquid at the temperature of step (b). The inert medium furthermore has a stable viscosity as a function of shear.

[0091] Preferably, the dispersion is subjected to the determined shear stress using a three-roll mill.

[0092] A preferred method is method (1) described in the Examples below.

[0093] Further details of the method according to the invention are described above in the context of the plurality of microcapsules according to the invention.

[0094] To the extent of any conflict or discrepancy between a document incorporated by reference and this specification, the present specification shall control.

[0095] The following examples are intended to illustrate, but not limit, the present invention. [Example]

[0096] Method (1) Sample preparation (a) Water-resistant microcapsules: 10–50 g of capsules were dispersed at a concentration of 5% in a 14% carboxymethylcellulose solution in deionized water. The dispersion was gently shaken to ensure a uniform concentration of microcapsules within the sample.

[0097] (b) Water-sensitive microcapsules: 10-50 g of microcapsules were dispersed in silicone oil (such as Priolube 3986) at a concentration of 5%. The dispersion was gently shaken to ensure a uniform concentration of microcapsules in the sample.

[0098] Silicone oil may also be used as a medium for measuring water-resistant capsules, and may offer certain advantages in the rheological properties of the solution, along with the microcapsules, such as viscosity stability during the application of shear by the triple-roll mill process.

[0099] The temperature of the sample obtained by procedure (a) or (b) was checked and adjusted to 20°C, as appropriate. The sample was poured into a funnel feeding the first gap of an Exakt three-roll mill, operated at a temperature of 20°C ± 2°C. The operating conditions of the mill were adjusted to give the desired shear stress for a maximum of 30 minutes, but preferably 10 minutes. The gap between the mills was greater than 30 microns, preferably greater than 50 microns, and preferably greater than 100 microns, but less than 1 cm.

[0100] At the mill outlet, droplets of the dispersion containing at least 100, preferably 150, microcapsules were examined within 30 minutes by optical microscopy using a Leica DMi8 microscope, equipped with an HCX Plan Apo 100x / 1.4-0.7 objective, operating in transmitted light mode. The total number of capsules examined and the total number of capsules broken were determined, and the percentage of broken capsules was calculated.

[0101] Examples 1-6 - Preparation of Multiple Microcapsules of the Present Invention

[0102] Example 1 - Preparation of double emulsion according to US2021113984

[0103] Step a): Preparation of the capsule core (dispersion of particles - composition C1b)

[0104] [Table 1]

[0105] Composition C1a was placed in a 35°C incubator and stirred at 500 rpm until the wax was completely melted. Composition B was placed in a 35°C incubator and stirred at 200 rpm until completely homogenized. Composition C1a was then added dropwise to composition B, still at 35°C, while stirring at 2000 rpm. The mixture was stirred at 2000 rpm for 5 minutes and then sonicated (Vibra-cell 75042, Sonics) for 20 minutes (pulse 5 s / 2 s) at 30% amplitude. If the temperature exceeded 35°C during sonication, the mixture was cooled on ice.

[0106] After cooling, 1.05 g of a modified polyethylene glycol gelling agent (Aculyn 44N, DOW) was added to the mixture while stirring at 500 rpm until gelation occurred, thus obtaining composition C1b.

[0107] [Table 2]

[0108] Composition C1 was added dropwise to composition C2 at temperature T while stirring at 2000 rpm.

[0109] Step c): Preparation of the second emulsion (E2)

[0110] [Table 3]

[0111] Composition C3 was stirred at 1000 rpm until completely homogenized. The first emulsion (E1) was then added dropwise to composition C3 at temperature T while stirring at 1200 rpm.

[0112] Step d): Size refinement of the second emulsion

[0113] The second polydisperse emulsion obtained in the previous step was stirred for 10 minutes at 1200 rpm at a temperature Td=20° C. A monodisperse emulsion (E3) was thus obtained.

[0114] Example 2 - Photopolymerization

[0115] A 3000 mL volume of double emulsion E3 was prepared as described above in Example 1. A convenient 1000 mL volume was prepared using a 70 s -1 A quartz flask was filled with the double emulsion E3, obtained as described above, with a transmittance of 0.9 and a viscosity of 5000 mP / s, to which a shear rate of 1000 mPa / s was applied. To obtain the mixed double emulsion E4, stirring was started and a light source, positioned perpendicular to the flask wall and with a maximum light intensity of 1 W / cm2, was used. 2 A UV lamp emitting at 365 nm having a flow rate of 300 mL / min was turned on. A flow of 300 mL / min of mixed polymerized double emulsion was continuously discharged through the discharge line while fresh double emulsion was fed through the feed line at the same rate.

[0116] The resulting microcapsules were monodisperse. Virtually no droplet fusion was observed. The conversion of reactive groups was at least 80%.

[0117] Samples taken from multiple microcapsules were tested using Method (1), Procedure (a) (Water Resistance) at a shear stress of 3 kPa. Less than 10% of the capsules were broken; Method (1), Procedure (a) (Water Resistance) was repeated at a shear stress of greater than 6 kPa. Less than 10% of the capsules were broken.

[0118] Example 2a The method of Example 2 was carried out, but the removed mixed double emulsion was poured into a quartz tube with a diameter of 5 cm and exposed to a maximum light intensity of 1 W / cm. 2 The sample was irradiated with a second UV lamp emitting at 365 nm.

[0119] The resulting microcapsules were monodisperse. Substantially no droplet fusion was observed. The conversion of reactive groups was at least 90%.

[0120] Samples taken from multiple microcapsules were tested using Method (1), Procedure (a) (Water Resistance) at a shear stress of greater than 3 kPa; less than 10% of the capsules were broken; Method (1), Procedure (a) (Water Resistance) was repeated at a shear stress of greater than 6 kPa; less than 10% of the capsules were broken.

[0121] Example 2b The method of Example 2 was carried out, except that the flask was equipped with a recycle line through which 50% of the discharged stream was recycled, and the feed rate of double emulsion E3 was adjusted accordingly.

[0122] The resulting microcapsules were monodisperse, and virtually no droplet fusion was observed.

[0123] The conversion of the reactive groups was at least 80%.

[0124] Samples taken from multiple microcapsules were tested using procedure (a) of method (1) (water resistance) at a shear stress of greater than 3 kPa. Less than 10% of the capsules were broken; procedure (a) of method (1) (water resistance) was repeated at a shear stress of greater than 6 kPa. Less than 10% of the capsules were broken.

[0125] Example 2c Double emulsion E3 was continuously applied at a shear rate of 70 s. -1 The mixed double emulsion was fed into the feed line of the flask at a rate of 300 ml / min and irradiation was carried out as described in Example 2.

[0126] The resulting microcapsules were monodisperse, and virtually no droplet fusion was observed.

[0127] The conversion of reactive groups was at least 80%.

[0128] Samples taken from multiple microcapsules were tested using procedure (a) of method (1) (water resistance) at a shear stress of greater than 3 kPa. Less than 10% of the capsules were broken; procedure (a) of method (1) (water resistance) was repeated at a shear stress of greater than 6 kPa. Less than 10% of the capsules were broken.

[0129] Example 2d The procedure of Example 2c was followed, but the mixed double emulsion was irradiated in a quartz tube according to Example 2a, instead of a flask.

[0130] The resulting microcapsules were monodisperse, and virtually no fusion of droplets was observed.

[0131] The conversion of the reactive groups was at least 80%.

[0132] Samples taken from multiple microcapsules were tested using Method (1), Procedure (a) (Water Resistance) at a shear stress of greater than 3 kPa. Less than 10% of the capsules were broken; Method (1), Procedure (a) (Water Resistance) was repeated at a shear stress of greater than 6 kPa. Less than 10% of the capsules were broken.

[0133] Comparative Example 1 200 ml of the double emulsion (E3) obtained in Example 1 was poured into a 500 ml beaker and exposed to a maximum light intensity of 1 W / cm 2 The sample was irradiated for 15 minutes with the aid of a UV light source (Dymax LightBox ECE2000) with a waveform length of 365 nm.

[0134] The resulting microcapsules were substantially monodisperse, although some droplet fusion was observed. The conversion of reactive groups was less than 75%.

[0135] Samples taken from multiple microcapsules were tested using Method (1), Procedure (a) (Water Resistance) at a shear stress of greater than 3 kPa. The percentage of capsules that broke was greater than 10% but less than 15%; Method (1), Procedure (a) (Water Resistance) was repeated at a shear stress of greater than 6 kPa. The percentage of capsules that broke was greater than 10% but less than 15%.

[0136] Example 3 Preparation of double emulsions according to US2020129948

[0137] Step a): Preparation of the first emulsion (E1)

[0138] [Table 4]

[0139] Composition C2 has the following properties:

[0140] Component CN1963 has two reactive acrylate functional groups per molecule and an average molecular weight of less than 5000 g / mol.

[0141] The crosslinker SR399 has five reactive acrylate functional groups per molecule and a molecular weight of 524.5 g / mol.

[0142] The Darocur 1173 photoinitiator has no reactive functional groups and a molecular weight of 164 g / mol. Composition C1 was added dropwise to composition C2 in a ratio of 3:7, under stirring at 2000 rpm. A first emulsion (E1) was thus obtained.

[0143] Step b): Preparation of the second emulsion (E2) [Table 5]

[0144] Composition C3 was stirred at 1000 rpm until completely homogenized, and then left to stand at room temperature for 1 hour. The first emulsion (E1) was added dropwise to composition C3 while stirring at 1000 rpm. A second emulsion (E2) was obtained.

[0145] Step c): Size refinement of the second emulsion. The second polydisperse emulsion (E2) obtained in the previous step was stirred for 10 minutes at 1000 rpm. A monodisperse emulsion (E3) was thus obtained.

[0146] Example 4 - Photopolymerization

[0147] A volume of 3000 mL of double emulsion E3 was prepared as described in Example 3 above. The feed line, discharge line, and stirring device were installed and the mixture was stirred for 70 s. -1 A 1000 mL convenient quartz flask was filled with the double emulsion E3 obtained as described above, with a transmittance of 0.9 and a viscosity of 5000 mPa·s, giving a shear rate of 1 W / cm. Stirring was started and a 1 W / cm fan, positioned perpendicular to the flask wall, was used to obtain the double emulsion E4.2 A UV lamp emitting at 365 nm was turned on with a maximum light intensity of 1000 μL / min. A 300 mL / min flow of mixed polymerized double emulsion was continuously discharged through the discharge line while fresh double emulsion was fed through the feed line at the same rate.

[0148] The resulting microcapsules were monodisperse. Substantially no droplet fusion was observed. The conversion of reactive groups was at least 80%.

[0149] Samples taken from multiple microcapsules were tested using procedure (a) of method (1) (water resistance) at a shear stress of greater than 3 kPa; procedure (a) of method (1) (water resistance) was repeated at a shear stress of greater than 6 kPa; the percentage of capsules that were broken was less than 10%.

[0150] Example 4a The method of Example 4 was carried out, except that the removed mixed double emulsion was poured into a quartz tube with a diameter of 5 cm and exposed to a maximum light intensity of 1 W / cm. 2 The mixture was irradiated with a second UV lamp emitting at 365 nm, and the quartz tube further contained a rotor-stator mixer.

[0151] The resulting microcapsules were monodisperse, and virtually no fusion of droplets was observed.

[0152] The conversion of reactive groups was at least 90%.

[0153] Samples taken from multiple microcapsules were tested using Method (1), Procedure (a) (Water Resistance) at a shear stress of greater than 3 kPa. Less than 5% of the capsules were broken; Method (1), Procedure (a) (Water Resistance) was repeated at a shear stress of greater than 6 kPa. Less than 5% of the capsules were broken.

[0154] Example 4b The method of Example 4 was carried out, except that the flask was equipped with a recycle line through which 50% of the discharged stream was recycled, and the feed rate of double emulsion E3 was adjusted accordingly.

[0155] The resulting microcapsules were monodisperse, and virtually no droplet fusion was observed.

[0156] The conversion of the reactive groups was at least 80%.

[0157] Samples taken from multiple microcapsules were tested using procedure (a) of method (1) (water resistance) at a shear stress of greater than 3 kPa. Less than 5% of the capsules were broken; procedure (a) of method (1) (water resistance) was repeated at a shear stress of greater than 6 kPa. Less than 5% of the capsules were broken.

[0158] Example 4c Double emulsion E3 was continuously applied at a shear rate of 70 s. -1 The mixed double emulsion was fed into the feed line of the flask at a rate of 300 ml / min and irradiation was carried out as described in Example 2.

[0159] The resulting microcapsules were monodisperse, and virtually no droplet fusion was observed.

[0160] The conversion of reactive groups was at least 80%.

[0161] Samples taken from multiple microcapsules were tested using procedure (a) of method (1) (water resistance) at a shear stress of greater than 3 kPa. Less than 10% of the capsules were broken; procedure (a) of method (1) (water resistance) was repeated at a shear stress of greater than 6 kPa. Less than 10% of the capsules were broken.

[0162] Example 4d The procedure of Example 2c was followed, but the mixed double emulsion was irradiated in a quartz tube according to Example 2a, instead of a flask.

[0163] The resulting microcapsules were monodisperse, and virtually no fusion of droplets was observed.

[0164] The conversion of the reactive groups was at least 80%.

[0165] Samples taken from multiple microcapsules were tested using Method (1), Procedure (a) (Water Resistance) at a shear stress of greater than 3 kPa. Less than 10% of the capsules were broken; Method (1), Procedure (a) (Water Resistance) was repeated at a shear stress of greater than 6 kPa. Less than 10% of the capsules were broken.

[0166] Comparative Example 2 200 ml of the double emulsion (E3) obtained in Example 1 was poured into a 500 ml beaker and exposed to a maximum light intensity of 1 W / cm 2 The sample was irradiated for 15 minutes with the aid of a UV light source (Dymax LightBox ECE2000) with a waveform length of 365 nm.

[0167] The resulting microcapsules were substantially monodisperse, although some droplet fusion was observed. The conversion of reactive groups was less than 75%.

[0168] Samples taken from multiple microcapsules were tested using Method (1), Procedure (a) (Water Resistance) at a shear stress of greater than 3 kPa. Less than 15% of the capsules were broken; Method (1), Procedure (a) (Water Resistance) was repeated at a shear stress of greater than 6 kPa. Less than 15% of the capsules were broken, but more than 10%.

[0169] Example 5 Preparation of double emulsions according to US2020129948

[0170] Step a) Preparation of the first emulsion (E1)

[0171] [Table 6]

[0172] Composition C2 has the following properties:

[0173] Component CN111 has five reactive functional groups per molecule and an average molecular weight of less than 2300 g / mol.

[0174] The crosslinker SR238 has two reactive acrylate functional groups per molecule and a molecular weight of 226 g / mol.

[0175] Composition C1 was added to composition C2 under mechanical stirring (IKA 2000) at 200 rpm, equipped with a stirring anchor. A primary emulsion (E1) was thus obtained.

[0176] Step b): Preparation of the second emulsion (E2)

[0177] [Table 7]

[0178] Composition C3 was stirred at 2000 rpm until completely homogenous, and then left to stand at room temperature for 1 hour. The first emulsion (E1) was then added all at once to composition C3 while stirring at 2000 rpm with a mechanical stirrer (IKA2000) equipped with a 3 cm diameter deflocculating stirring propeller. A second emulsion (E2) was obtained.

[0179] Step c): Size refinement of the second emulsion. The second polydisperse emulsion (E2) obtained in the previous step was stirred for 2 minutes at 2000 rpm. A monodisperse emulsion (E3) was thus obtained.

[0180] Step d): A volume of 3000 mL of double emulsion E3 was prepared as described in Example 3 above. The feed line, drain line, and -1 A 1000 mL convenient quartz flask equipped with a stirring device giving a shear rate of 1 W / cm was filled with the double emulsion E3 obtained as described above, with a transmittance of 0.9 and a viscosity of 5000 mPa·s. To obtain the mixed double emulsion E4, stirring was started and a 1 W / cm stirrer was placed perpendicular to the wall of the flask. 2 A UV lamp emitting at 365 nm was turned on with a maximum light intensity of 1000 μL / min. A 300 mL / min flow of mixed polymerized double emulsion was continuously discharged through the discharge line while fresh double emulsion was fed through the feed line at the same rate.

[0181] The resulting microcapsules were monodisperse. Substantially no droplet fusion was observed. The conversion of reactive groups was at least 80%.

[0182] Samples taken from multiple microcapsules were tested using procedure (a) of method (1) (water resistance) at a shear stress of greater than 3 kPa. Less than 10% of the capsules were broken; procedure (a) of method (1) (water resistance) was repeated at a shear stress of greater than 6 kPa. Less than 10% of the capsules were broken.

[0183] Example 6 CN104D80 - Bisphenol A Epoxy Acrylate 75%, 20% SR238, 5% Darocur 1173

[0184] Preparation of double emulsions according to US2020129948

[0185] Step a): Preparation of the first emulsion (E1)

[0186] [Table 8]

[0187] Composition C2 has the following properties:

[0188] Component CN104D80 has two reactive acrylate functional groups per molecule of bisphenol A epoxy acrylate and three reactive functional groups per molecule of acrylic acid and glycerol, propoxylated ester, with an average molecular weight of less than 750 g / mol.

[0189] The crosslinker SR238 has two reactive acrylate functional groups per molecule and a molecular weight of 226 g / mol.

[0190] Composition C1 was added to composition C2 in 5 minutes under mechanical stirring (IKA 2000) at 200 rpm, equipped with a stirring anchor. A primary emulsion (E1) was thus obtained.

[0191] Step b): Preparation of the second emulsion (E2) [Table 9]

[0192] Composition C3 was stirred at 2000 rpm until completely homogenous, and then left at room temperature for 1 hour. The first emulsion was added to composition C3 all at once while stirring at 2000 rpm with a mechanical stirrer (IKA2000) equipped with a 3 cm diameter deflocculating stirring propeller. A second emulsion (E2) was obtained.

[0193] Step c): Size refinement of the second emulsion. The second polydisperse emulsion (E2) obtained in the previous step was stirred for 2 minutes at 2000 rpm. A monodisperse emulsion (E3) was thus obtained.

[0194] Step d): A volume of 3000 mL of double emulsion E3 was prepared as described in Example 3 above. The feed line, drain line, and -1A 1000 mL convenient quartz flask equipped with a stirring device giving a shear rate of 1 W / cm was filled with the double emulsion E3 obtained as described above, with a transmittance of 0.9 and a viscosity of 5000 mPa·s. To obtain the mixed double emulsion E4, stirring was started and a 1 W / cm stirrer was placed perpendicular to the wall of the flask. 2 A UV lamp emitting at 365 nm with a maximum light intensity of 1000 nm was turned on. A 300 mL / min flow of mixed polymerized double emulsion was continuously discharged through the discharge line while fresh double emulsion was fed through the feed line at the same rate. The resulting microcapsules were monodisperse. Virtually no droplet fusion was observed. The conversion of reactive groups was at least 80%.

[0195] Samples taken from multiple microcapsules were tested using procedure (a) of method (1) (water resistance) at a shear stress of greater than 3 kPa. Less than 10% of the capsules were broken; procedure (a) of method (1) (water resistance) was repeated at a shear stress of greater than 6 kPa. Less than 10% of the capsules were broken.

Claims

1. 1. A plurality of microcapsules having a crosslinked polymer shell encapsulating an active ingredient, the crosslinked polymer shell comprising or consisting of at least one polymer selected from aliphatic epoxidized polyacrylates, such as soybean oil acrylate, bisphenol A-based epoxy acrylate, glycerol propoxy triacrylate, difunctional polyester acrylate oligomers, aliphatic polyester-based urethane dimethacrylates or diacrylates, and amine-modified polyether acrylates.

2. 10. The plurality of microcapsules according to claim 1, wherein the crosslinked polymer shell comprises or consists of at least one polymer selected from aliphatic epoxidized polyacrylates, in particular soybean oil acrylate.

3. 3. The plurality of microcapsules of claim 1 or 2, wherein the crosslinked polymer shell comprises or consists of at least one polymer selected from bisphenol A-based epoxy acrylates.

4. 4. A plurality of microcapsules according to any one of claims 1 to 3, wherein the crosslinked polymer shell comprises or consists of at least one polymer selected from glycerol propoxy triacrylate.

5. 5. A plurality of microcapsules according to any one of claims 1 to 4, wherein the crosslinked polymer shell comprises or consists of at least one polymer selected from difunctional polyester acrylate oligomers.

6. 6. A plurality of microcapsules according to any one of claims 1 to 5, wherein the crosslinked polymer shell comprises or consists of at least one polymer selected from aliphatic polyester-based urethane dimethacrylates or diacrylates.

7. 7. A plurality of microcapsules according to any one of claims 1 to 6, wherein the crosslinked polymer shell comprises or consists of at least one polymer selected from amine-modified polyether acrylates.

8. 8. The plurality of microcapsules according to any one of claims 1 to 7, wherein the crosslinked polymer shell comprises 50% to 80% by weight of said at least one polymer, based on the total weight of the crosslinked polymer shell.

9. 9. A plurality of microcapsules according to any one of claims 1 to 8, wherein the crosslinked polymer shell has a degree of crosslinking, determined by observation of a decrease in FTIR absorption of an FTIR absorption band characteristic of a crosslinked precursor group of the crosslinked polymer shell, that is 80% or more, preferably 90% or more.

10. 10. The plurality of microcapsules of claim 9, wherein the crosslink precursor groups are selected from acrylate groups and methacrylate groups.

11. 11. The plurality of microcapsules according to any one of claims 1 to 10, wherein when a dispersion of the plurality of microcapsules in an inert medium is subjected to a shear stress of 3 kPa or more and 1 MPa or less at a temperature of about 20°C, the dispersion has mechanical resistance such that, after being subjected to the shear stress for 10 minutes, the proportion of broken capsules observed by microscope is less than 10%.

12. 12. The plurality of microcapsules according to any one of claims 1 to 11, wherein when a dispersion of the plurality of microcapsules in an inert medium is subjected to a shear stress of about 3 kPa at a temperature of about 20°C, the dispersion has mechanical resistance such that, after being subjected to the shear stress for 10 minutes, the proportion of broken capsules observed by microscope is less than 10%.

13. 13. The plurality of microcapsules according to any one of claims 1 to 12, having mechanical resistance such that when the plurality of microcapsules are subjected to a shear stress of 6 kPa or more in an inert medium at a temperature of about 20°C, the proportion of broken capsules observed by microscope after subjecting the plurality of microcapsules to the shear stress for 10 minutes is less than 10%.

14. 14. The plurality of microcapsules according to any one of claims 1 to 13, which have a mechanical resistance such that when the plurality of microcapsules are subjected to a shear stress of 30 kPa or less, in particular 15 kPa or less, in an inert medium at a temperature of about 20°C, the proportion of ruptured capsules observed by microscope after subjecting the plurality of microcapsules to said shear stress for 10 minutes is less than 10%.

15. 15. The plurality of microcapsules of any one of claims 11 to 14, wherein the percentage of ruptured capsules observed by microscope after being subjected to the shear stress is less than 5%.

16. 16. A plurality of microcapsules according to any one of claims 11 to 15, wherein the percentage of ruptured capsules observed by microscope after being subjected to the shear stress is 0% or more, in particular 1% or more.

17. A plurality of microcapsules according to any one of claims 11 to 16, wherein the mechanical resistance is measured by the method (1) described in the specification.

18. 18. The plurality of microcapsules of any one of claims 1 to 17, having a diameter of between 1 μm and 30 μm and a mechanical resistance such that when the plurality of microcapsules is subjected to a force of 3000 μN, the proportion of ruptured capsules does not exceed 10%, as determined by optical microscopy.

19. 20. The plurality of microcapsules of claim 18, wherein the percentage of broken capsules is greater than 0% and less than or equal to 5%, preferably greater than 0% and less than or equal to 1%.

20. 20. The plurality of microcapsules of claim 18, wherein the plurality of microcapsules has a mechanical resistance such that when subjected to a compressive stress of 1 MPa, the percentage of ruptured capsules does not exceed 10% as determined by optical microscopy.

21. 20. The plurality of microcapsules of claim 18, wherein the plurality of microcapsules has a mechanical resistance such that when subjected to a compressive stress of 1 MPa, the percentage of broken capsules does not exceed 5% as determined by optical microscopy.

22. 20. The plurality of microcapsules of claim 18, wherein the plurality of microcapsules has a mechanical resistance such that when subjected to a compressive stress of 2 MPa, the percentage of ruptured capsules does not exceed 10% as determined by optical microscopy.

23. 20. The plurality of microcapsules of claim 18, wherein the plurality of microcapsules has a mechanical resistance such that when subjected to a compressive stress of 2 MPa, the percentage of ruptured capsules does not exceed 5% as determined by optical microscopy.

24. 20. The plurality of microcapsules of claim 18, wherein the plurality of microcapsules has a mechanical resistance such that when subjected to a compressive stress of 3 MPa, the percentage of broken capsules does not exceed 10% as determined by optical microscopy.

25. 20. The plurality of microcapsules of claim 18, wherein the plurality of microcapsules has a mechanical resistance such that when subjected to a compressive stress of 3 MPa, the percentage of broken capsules does not exceed 5% as determined by optical microscopy.

26. 26. A plurality of microcapsules according to any one of claims 1 to 25, wherein the microcapsules have an average diameter of from 1 μm to 30 μm and a wall thickness of from 0.1 μm to 20 μm.

27. 27. A plurality of microcapsules according to any one of claims 1 to 26, which are monodisperse.

28. 28. The plurality of microcapsules of any one of claims 1 to 27, wherein the average diameter of the microcapsules is from 1 μm to 30 μm, the thickness of the solid coating shell is from 0.2 μm to 8 μm, and the standard deviation of the distribution of microcapsule diameters is less than 50%, or less than 1 μm.

29. 29. The plurality of microcapsules of any one of claims 1 to 28, wherein the pores on the shell surface of the microcapsules have an average diameter of less than 1 nm as determined by BET surface analysis.

30. 30. The plurality of microcapsules according to any one of claims 1 to 29, wherein the crosslinked polymer shell is obtained by photopolymerization of a photopolymerizable composition C2 comprising at least a monomer having a reactive group and a photoinitiator.

31. 31. A plurality of microcapsules according to claim 30, wherein the conversion of reactive groups of the photopolymerizable composition C2 is at least 80%, preferably at least 90%.

32. 32. The plurality of microcapsules of any one of claims 1 to 31, wherein the crosslinked polymer shell is essentially free of nitrile functional groups.

33. 33. The plurality of microcapsules of any one of claims 1 to 32, wherein the active ingredient is a solid at 25°C.

34. 33. The plurality of microcapsules of any one of claims 1 to 32, wherein the active ingredient is liquid at 25°C under a pressure of 1013.25 kPa.

35. 35. The plurality of microcapsules of any one of claims 1 to 34, wherein the active ingredient is selected from catalysts, UV absorbers, lubricants and flame retardants, pigments, pesticides, and liquid crystal materials.

36. 36. The plurality of microcapsules according to any one of claims 1 to 35, wherein the active ingredient encapsulated in the microcapsules is a latent accelerator for the curing of epoxy resins, for example selected from amine latent accelerators, in particular polyamine latent accelerators.

37. 37. The plurality of microcapsules of any one of claims 1 to 36, wherein the active ingredient is not a foaming agent.

38. 38. The plurality of microcapsules of any one of claims 1 to 37, wherein the active ingredient is a lubricant.

39. 40. The plurality of microcapsules of claim 38, wherein the active ingredient encapsulated in the microcapsules is a polyol ester lubricant.

40. 40. The plurality of microcapsules according to any one of claims 1 to 39, wherein the active ingredient is selected from oils, in particular mineral oils, polyalphaolefins, polyglycols, synthetic esters, phosphate esters, triglyceride esters, polyol esters, fatty acids, vegetable oils, silicone oils, polyethers, perfluoropolyethers, and solid lubricants, in particular amides such as erucamide or ethylene bis(stearamide), and synthetic or natural waxes, such as paraffin.

41. 41. A plurality of microcapsules according to any one of claims 1 to 40, obtainable by a process comprising the steps of: (a) providing a double emulsion comprising droplets of at least one active ingredient (C1) dispersed in a photopolymerizable composition C2, said droplets being dispersed in a composition C3, such that compositions C2 and C3 are immiscible with each other; (b) introducing a controlled shear rate to the double emulsion to provide a mixed double emulsion (C4); and (c) irradiating the mixed double emulsion (C4) to prepare the microcapsules.

42. A polymeric composition comprising a plurality of microcapsules according to any one of claims 1 to 41.

43. 43. The polymer composition of claim 42, wherein the polymer is a thermoplastic polymer.

44. 44. The polymer composition of claim 43, wherein the thermoplastic polymer is selected from polyolefins, such as polyethylene and polypropylene, polyvinyl chloride, polystyrene, polyamides and polyesters.

45. 43. The polymer composition of claim 42, wherein the polymer is a thermosetting polymer.

46. 46. ​​The polymer composition of claim 45, wherein the thermosetting polymer comprises or consists of an epoxy resin.

47. 43. The polymer composition of claim 42, wherein the polymer is an elastomer.

48. 48. The polymer composition of any one of claims 42 to 47, comprising 0.5% to 20%, preferably 1% to 10%, by weight of a plurality of microcapsules and 80% to 99.5%, preferably 90% to 99%, by weight of polymer, relative to the total weight of the polymer composition.

49. Use of a plurality of microcapsules according to any one of claims 1 to 41 for the delivery of an active ingredient to a polymerisation or polymerisation processing step.

50. 50. The use according to claim 49 for the preparation of thermosetting polymers.

51. 50. Use according to claim 49 for the manufacture of moulded, extruded or cast thermoplastic articles.

52. 52. Use according to claim 51 for the manufacture of compression moulded or injection moulded thermoplastic articles.

53. A premix for producing a thermosetting polymer, comprising a plurality of microcapsules according to any one of claims 1 to 41.

54. 54. The premix of claim 53, comprising an epoxy resin.

55. 55. A premix according to claim 53 or 54, wherein the active ingredient is a latent accelerator for the curing of epoxy resins.

56. 54. The premix of claim 53, comprising an isocyanate resin and a plurality of microcapsules of any one of claims 1 to 41.

57. 57. The premix of claim 56, wherein the plurality of microcapsules contains at least a polyol as an active ingredient.

58. A premix comprising an acrylic resin, a vinyl resin and a polyester, and a plurality of microcapsules according to any one of claims 1 to 41.

59. 59. The premix of claim 58, wherein the plurality of microcapsules preferably contains, as an activator, an unsaturated monomer diluent selected from acrylic acid, acrylamide, acryloyl chloride, and methyl methacrylate.

60. A mixture comprising a thermoplastic polymer and a plurality of microcapsules according to any one of claims 1 to 41.

61. 40. Use of a plurality of microcapsules according to claim 38 or 39 to increase the abrasion or scratch resistance of a polymer surface.

62. 40. Use of a plurality of microcapsules according to claim 38 or 39 to enhance the water resistance of a polymer surface.

63. 40. Use of a plurality of microcapsules according to claim 38 or 39 for the self-lubrication of elastomers.

64. A plurality of microcapsules having a crosslinked polymer shell encapsulating an active ingredient, wherein the plurality of microcapsules have a mechanical resistance such that when a dispersion of the plurality of microcapsules in an inert medium is subjected to a shear stress of 3 kPa or more and 1 MPa or less at a temperature of about 20°C, the proportion of capsules broken, as observed under a microscope, is less than 10% after the dispersion is subjected to the shear stress for 10 minutes.

65. 65. The plurality of microcapsules of claim 64, wherein a dispersion of the plurality of microcapsules in an inert medium, when subjected to a shear stress of about 3 kPa at a temperature of about 20° C., has a mechanical resistance such that less than 10% of capsules are broken when observed under a microscope after the dispersion has been subjected to said shear stress for 10 minutes.

66. The plurality of microcapsules of any one of claims 1 to 64, wherein a dispersion of the plurality of microcapsules in an inert medium, when subjected to a shear stress of 6 kPa or more at a temperature of about 20° C., has a mechanical resistance such that less than 10% of capsules are broken when observed under a microscope after the plurality of microcapsules have been subjected to said shear stress for 10 minutes.

66. 66. A plurality of microcapsules according to claim 64 or 65, which have a mechanical resistance when the plurality of microcapsules in an inert medium are subjected to a shear stress of 30 kPa or less, in particular 15 kPa or less, at a temperature of about 20°C, such that after subjecting the plurality of microcapsules to said shear stress for 10 minutes, the proportion of ruptured capsules, as observed under a microscope, is less than 10%.

67. 67. The plurality of microcapsules of any one of claims 64 to 66, wherein the percentage of ruptured capsules observed under a microscope after subjecting to said shear stress is less than 5%.

68. 68. A plurality of microcapsules according to any one of claims 64 to 67, wherein the percentage of ruptured capsules observed under a microscope after being subjected to said shear stress is 0% or more, in particular 1% or more.

69. 69. A plurality of microcapsules according to any one of claims 64 to 68, wherein the mechanical resistance is measured by the method (1) described in the specification.

70. A plurality of microcapsules having a diameter of 1 μm to 30 μm and having a mechanical resistance such that when the plurality of microcapsules are subjected to a force of 3000 μN, the percentage of broken capsules does not exceed 10% as determined by optical microscopy.

71. 71. The plurality of microcapsules of claim 70, wherein the percentage of broken capsules is greater than 0% and less than or equal to 5%, preferably greater than 0% and less than or equal to 1%.

72. 71. The plurality of microcapsules of claim 70, wherein the plurality of microcapsules has a mechanical resistance such that when subjected to a compressive stress of 1 MPa, the proportion of broken capsules does not exceed 10% as determined by optical microscopy.

73. 71. The plurality of microcapsules of claim 70, wherein the plurality of microcapsules has a mechanical resistance such that when subjected to a compressive stress of 1 MPa, the percentage of broken capsules does not exceed 5% as determined by optical microscopy.

74. 71. The plurality of microcapsules of claim 70, wherein the plurality of microcapsules has a mechanical resistance such that when subjected to a compressive stress of 2 MPa, the proportion of broken capsules does not exceed 10% as determined by optical microscopy.

75. 71. The plurality of microcapsules of claim 70, wherein the plurality of microcapsules has a mechanical resistance such that when subjected to a compressive stress of 2 MPa, the percentage of broken capsules does not exceed 5% as determined by optical microscopy.

76. 71. The plurality of microcapsules of claim 70, wherein the plurality of microcapsules has a mechanical resistance such that when subjected to a compressive stress of 3 MPa, the percentage of broken capsules does not exceed 10% as determined by optical microscopy.

77. 71. The plurality of microcapsules of claim 70, wherein the plurality of microcapsules has a mechanical resistance such that when subjected to a compressive stress of 3 MPa, the percentage of broken capsules does not exceed 5% as determined by optical microscopy.

78. A plurality of microcapsules having a crosslinked polymer shell encapsulating an active ingredient, wherein the crosslinked polymer shell has a degree of crosslinking of 80% or more, preferably 90% or more, as determined by observation of a decrease in FTIR absorption of a characteristic FTIR absorption band of a crosslink precursor group of the crosslinked polymer shell.

79. A plurality of microcapsules according to any one of claims 70 to 78 according to a plurality of microcapsules according to any one of claims 64 to 69.

80. 80. The plurality of microcapsules of any one of claims 64 to 79, wherein the microcapsules have an average diameter of from 1 μm to 30 μm and a wall thickness of from 0.1 μm to 20 μm.

81. 81. A plurality of microcapsules according to any one of claims 64 to 80, which are monodisperse.

82. 82. The plurality of microcapsules of any one of claims 64 to 79 and 81, wherein the average diameter of the microcapsules is from 1 μm to 30 μm, the thickness of the solid coating shell is from 0.2 μm to 8 μm, and the standard deviation of the distribution of microcapsule diameters is less than 50%, or less than 1 μm.

83. 83. A plurality of microcapsules according to any one of claims 64 to 82, wherein the pores on the shell surface of the microcapsules have an average diameter of less than 1 nm as determined by BET surface analysis.

84. 84. The plurality of microcapsules of any one of claims 64 to 83, wherein the crosslinked polymer shell is obtained by photopolymerization of a photopolymerizable composition having reactive groups.

85. 85. A plurality of microcapsules according to claim 84, wherein the conversion of reactive groups of the photopolymerizable composition C2 is at least 80%, preferably at least 90%.

86. 86. The plurality of microcapsules of any one of claims 64 to 85, wherein the crosslinked polymer shell comprises or consists of at least one polymer selected from polyethers, polyesters, polyurethanes, polyureas, polyethylene glycols, polypropylene glycols, polyamides, polyacetals, polyimides, polyolefins, polysulfides, and polydimethylsiloxanes, said polymer having at least one reactive functional group selected from the group consisting of acrylates; methacrylates; vinyl ethers; N-vinyl ethers; mercaptoesters; thiolenes; siloxanes; epoxies; oxetanes; urethanes; isocyanates; and peroxides.

87. 87. The plurality of microcapsules of any one of claims 64 to 86, wherein the crosslinked polymer shell is essentially free of nitrile functional groups.

88. 88. The plurality of microcapsules of any one of claims 64 to 87, wherein the active ingredient is a solid at 25°C.

89. 88. The plurality of microcapsules of any one of claims 64 to 87, wherein the active ingredient is liquid at a pressure of 1013.25 kPa and 25°C.

90. 90. The plurality of microcapsules of any one of claims 64 to 89, wherein the active ingredient is selected from catalysts, UV absorbers, lubricants and flame retardants, pigments, and liquid crystal materials.

91. 91. The plurality of microcapsules of any one of claims 64 to 90, wherein the active ingredient is not a foaming agent.

92. 92. The plurality of microcapsules of any one of claims 64 to 91, wherein the active ingredient is a lubricant.

93. 93. A plurality of microcapsules according to any one of claims 64 to 92, obtainable by a process comprising the steps of: (a) providing a double emulsion comprising droplets of at least one active ingredient (C1) dispersed in a photopolymerizable composition C2, said droplets being dispersed in a composition C3, such that compositions C2 and C3 are immiscible with each other; (b) introducing a controlled shear rate to the double emulsion to provide a mixed double emulsion (C4); and (c) irradiating the mixed double emulsion (C4) to prepare the microcapsules.

94. 94. Use of a plurality of microcapsules according to any one of claims 64 to 93 for the delivery of an active ingredient to a polymerization or polymerization processing step.

95. 94. Use according to claim 93 for the production of thermosetting polymers.

96. 94. Use according to claim 93 for the manufacture of moulded, extruded or cast thermoplastic articles.

97. 97. Use according to claim 96 for the manufacture of compression moulded or injection moulded thermoplastic articles.

98. A premix for producing a thermosetting polymer comprising a plurality of microcapsules according to any one of claims 64 to 93.

99. 99. The premix of claim 98, comprising an epoxy resin.

100. 99. The premix of claim 98, wherein the active ingredient is a latent accelerator for the cure of epoxy resins.

101. A mixture comprising a thermoplastic polymer and a plurality of microcapsules according to any one of claims 64 to 93.

102. A polymeric composition comprising a plurality of microcapsules according to any one of claims 64 to 93.

103. 93. Use of a plurality of microcapsules according to claim 92 to enhance the abrasion or scratch resistance of a polymer surface.

104. 93. Use of a plurality of microcapsules according to claim 92 to enhance the abrasion resistance of a polymer surface.

105. 93. Use of a plurality of microcapsules according to claim 92 for the self-lubrication of elastomers.

106. 106. The use of claim 105, wherein the lubricant is a polyol ester.

107. A method for determining the mechanical resistance of a plurality of microcapsules having a core and a polymer shell, comprising the steps of: (a) preparing a dispersion of a plurality of microcapsules in an inert medium; (b) subjecting the dispersion to a determined shear stress at a specified temperature for a specified time; and (c) after step (b), determining by microscopy the percentage of capsules that have broken.

108. 108. The method of claim 107, wherein the inert medium is a clear and viscous liquid at the temperature of step (b).

109. 109. The method according to claim 107 or 108, which is method (1) described in the specification.

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