Copolymers, compositions and their uses

Abstract

The present invention relates to a copolymer obtained by polymerization of a monomer mixture comprising: (a) at least one monomer selected from the group consisting of 2-octyl (meth)acrylate, 2-methylbutyl acrylate, and 3-methylbutyl acrylate; (b) isobornyl (meth)acrylate; (c) optionally at least one carboxyl-functionalized ethylenically unsaturated monomer; and (d) optionally at least one ethylenically unsaturated monomer other than (a), (b), and (c). Compositions comprising the copolymer and its use in adhesives and coatings are also provided.

Description

[Technical Field]

[0001] The present invention relates to copolymers obtained by polymerization of specific combinations of monomers that may be of renewable origin (i.e., bio-derived monomers), compositions comprising said copolymers, and their use, especially in adhesives and coatings. [Background technology]

[0002] (Meth)acrylic copolymers are copolymers of (meth)acryloyl functional groups (—CO—C(R)) such as acrylic acid, methacrylic acid, their esters, and their amides. 1 )=CH2, where R 1 (Meth)acrylic copolymers are a general term for copolymers obtained by the polymerization of two or more monomers containing (C, C, D, E ...

[0003] Currently, most raw materials for preparing (meth)acrylic copolymers are still petroleum-based. For example, 2-ethylhexyl acrylate (2-EHA) can be easily copolymerized with a wide range of other (meth)acrylic or vinyl monomers, giving the copolymers a low glass transition temperature (Tg) (the Tg of the homopolymer of 2-EHA is −70° C.), but is petroleum-derived and therefore unsustainable. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Patent Application No. 2013 / 064775 Summary of the Invention [Problem to be solved by the invention]

[0005] In modern times, the current challenge is to meet the demand for more sustainable, environmentally friendly, energy-efficient, and greener technologies. The replacement of oil / petroleum-based raw materials with bio-based or renewable raw materials can significantly contribute to reducing the carbon footprint of the final product. Much research has been carried out to synthesize and commercialize new bio-based materials derived from renewable sources, such as plants. Examples of monomers that can be bio-derived include 2-octyl (meth)acrylate, 3-methylbutyl acrylate, 2-methylbutyl acrylate, isobornyl (meth)acrylate, itaconic acid and their esters, etc.

[0006] There is growing interest in utilizing potentially bio-based monomers and processes for environmentally friendly products. Although some efforts have been made to replace all or part of petroleum-based raw materials with potentially bio-based monomers when preparing (meth)acrylic copolymers, there remains a need for novel (meth)acrylic copolymers that exhibit both good optical properties (e.g., transparency and low turbidity) and mechanical properties (e.g., peel strength, holding power, and aging stability) that can be used as adhesives or coatings in electronics and touchscreen applications. [Means for solving the problem]

[0007] The first object of the present invention is to provide a copolymer, which comprises, based on the total weight of the monomer mixture: (a) from 45 to 95% by weight, in particular from 45 to 90% by weight, from 48 to 80% by weight, or from 50 to 70% by weight, of at least one monomer selected from the group consisting of 2-octyl (meth)acrylate, 2-methylbutyl acrylate, 3-methylbutyl acrylate, and mixtures thereof; (b) 5 to 55% by weight, in particular 10 to 55% by weight, 20 to 52% by weight, or 30 to 50% by weight, of isobornyl (meth)acrylate, (c) 0 to 5% by weight, particularly 0 to 2% by weight, 0 to 1% by weight, or even 0% by weight, of at least one carboxyl-functionalized ethylenically unsaturated monomer, and (d) 0 to 30% by weight, in particular 0 to 20% by weight, 0 to 10% by weight, or 0 to 5% by weight, of at least one ethylenically unsaturated monomer other than (a), (b), and (c). The polymerizable monomer is obtained by polymerizing a monomer mixture containing the following:

[0008] A second object of the invention relates to compositions comprising the copolymers of the invention.

[0009] Another object of the present invention relates to the use of the composition of the present invention in preparing or as an adhesive or coating. The composition containing the copolymer of the present invention may have mechanical properties and optical performance comparable to or better than conventional petroleum-based compositions. At the same time, since the copolymer of the present invention can be prepared based on renewable resources, it can be used to develop sustainable products that reduce environmental burden and social impact.

[0010] The present invention also provides an article comprising at least one film formed by curing a composition of the present invention, the film having a transmittance of 95% or greater and a haze of 0.5% or less. DETAILED DESCRIPTION OF THE INVENTION

[0011] The invention is explained in more detail in the following description without being limited thereto.

[0012] As used herein, the term "ethylenically unsaturated compound" refers to a compound containing a polymerizable carbon-carbon double bond. A polymerizable carbon-carbon double bond is a carbon-carbon double bond that can react with another carbon-carbon double bond in a polymerization reaction. The polymerizable carbon-carbon double bond is usually contained in a group selected from acrylate (including cyanoacrylate), methacrylate, acrylamide, methacrylamide, styrene, maleate, fumarate, itaconate, allyl, propenyl, vinyl, and combinations thereof, preferably selected from acrylate, methacrylate, and vinyl, more preferably selected from acrylate and methacrylate. Carbon-carbon double bonds in phenyl rings are not considered polymerizable carbon-carbon double bonds.

[0013] As used herein, the term "(meth)acrylic" refers to acrylic, methacrylic, or a mixture thereof. (Meth)acrylic groups encompass (meth)acrylate groups and (meth)acrylamide groups. The term "(meth)acrylate" refers to acrylate, methacrylate, or a mixture thereof. The term "(meth)acrylamide" refers to acrylamide, methacrylamide, or a mixture thereof.

[0014] As used herein, the terms "bio-based" or "bio-derived" are used to describe materials, substances, or monomers that can be obtained as far as possible from renewable sources, such as plants, and can therefore be considered materials of renewable origin. A bio-derived material can be characterized by its bio-renewable carbon content (%BRC). The %BRC of a material refers to the percentage of carbon content derived from biomass in the total carbon content of the material. The formula for calculating %BRC is as follows:

[0015]

number

[0016] With respect to the copolymers according to the present invention, "bio-based carbon" refers specifically to the amount of carbonated bio-based raw materials incorporated to prepare the copolymer, and "fossil carbon" refers specifically to the amount of carbonated raw materials obtained from fossil sources incorporated to prepare the copolymer.

[0017] As used herein, the monomers used to prepare the copolymers of the present invention may be bio-derived, including, but not limited to, 2-octyl (meth)acrylate, 2-methylbutyl acrylate, 3-methylbutyl acrylate, and isobornyl (meth)acrylate.

[0018] For example, 2-octyl (meth)acrylate can be prepared from 2-octanol and (meth)acrylic acid in the presence of an acidic sulfur-containing esterification catalyst, such as methanesulfonic acid, and at least one polymerization inhibitor. Alternatively, it can be prepared by transesterification between a lower (meth)acrylate, such as methyl (meth)acrylate or ethyl (meth)acrylate, and 2-octanol. Advantageously, the 2-octanol can be obtained from the treatment of castor oil-derived ricinoleic acid with sodium hydroxide, followed by distillation to remove sebacic acid. A process for preparing 2-octyl acrylate by direct esterification is described, inter alia, in International Patent Application No. 2013 / 064775.

[0019] On the other hand, 2-methylbutyl acrylate and 3-methylbutyl acrylate can be prepared from 2-methylbutyl alcohol and 3-methylbutyl alcohol, respectively, and acrylic acid in the presence of an acidic sulfur-containing esterification catalyst, such as methanesulfonic acid, and at least one polymerization inhibitor. Alternatively, they can be prepared by transesterification between a lower acrylate, such as methyl acrylate or ethyl acrylate, and 2-methylbutyl alcohol or 3-methylbutyl alcohol. Advantageously, 2-methylbutyl alcohol and 3-methylbutyl alcohol can be derived from fusel alcohols, which are by-products of the alcoholic fermentation of plants, such as fruits or grains.

[0020] Isobornyl (meth)acrylate is typically synthesized by reacting camphene with (meth)acrylic acid in the presence of an acid catalyst and at least one inhibitor. Camphene is one of the most common terpenes found in nature and appears as colorless crystals with the distinct, pungent odor of camphor oil. It is abundant in the essential oils of many plants, such as cypress, valerian, holy basil, nutmeg, sage, ginger, neroli, and rosemary.

[0021] Copolymer The copolymer of the present invention comprises, based on the total weight of the monomer mixture: (a) from 45 to 95% by weight, in particular from 45 to 90% by weight, from 48 to 80% by weight, or from 50 to 70% by weight, of at least one monomer selected from the group consisting of 2-octyl (meth)acrylate, 2-methylbutyl acrylate, 3-methylbutyl acrylate, and mixtures thereof; (b) 5 to 55% by weight, in particular 10 to 55% by weight, 20 to 52% by weight, or 30 to 50% by weight, of isobornyl (meth)acrylate, (c) 0 to 5% by weight, particularly 0 to 2% by weight, 0 to 1% by weight, or even 0% by weight, of at least one carboxyl-functionalized ethylenically unsaturated monomer, and (d) 0 to 30% by weight, in particular 0 to 20% by weight, 0 to 10% by weight, or 0 to 5% by weight, of at least one ethylenically unsaturated monomer other than (a), (b), and (c). The polymerizable monomer is obtained by polymerizing a monomer mixture comprising or consisting of:

[0022] The total weight of components (a)+(b)+(c)+(d) may represent 100% of the weight of the monomer mixture.

[0023] Component (a) comprises at least one monomer selected from the group consisting of 2-octyl (meth)acrylate, 2-methylbutyl acrylate, 3-methylbutyl acrylate, and mixtures thereof.

[0024] In one embodiment, component (a) consists of a single monomer selected from the group consisting of 2-octyl(meth)acrylate, 2-methylbutyl acrylate, and 3-methylbutyl acrylate.

[0025] Alternatively, component (a) may consist of a mixture of 2-octyl(meth)acrylate and at least one monomer selected from 3-methylbutyl acrylate, 2-methylbutyl acrylate, and mixtures thereof. In particular, component (a) may comprise, relative to the total weight of component (a), (a1) 1 to 99% by weight of 2-octyl (meth)acrylate, and (a2) It may consist of 1 to 99% by mass of 3-methylbutyl acrylate and / or 2-methylbutyl acrylate.

[0026] The total mass of components (a1)+(a2) may represent 100% of the mass of component (a).

[0027] The mass ratio of component (a1) to component (a2) is not particularly limited and can be adjusted depending on the expected characteristics of the copolymer, such as Tg and % BRC. In a preferred example, component (a) may consist of 30 to 99 mass% of 2-octyl (meth)acrylate and 1 to 70 mass% of 3-methylbutyl acrylate and / or 2-methylbutyl acrylate, based on the total mass of component (a). In a more preferred example, component (a) may consist of 50 to 99 mass% of 2-octyl (meth)acrylate and 1 to 50 mass% of 3-methylbutyl acrylate and / or 2-methylbutyl acrylate, based on the total mass of component (a).

[0028] Component (b) is composed of isobornyl (meth)acrylate. Isobornyl (meth)acrylate is a highly hydrophobic monomer with a high Tg. The bicyclic structure of isobornyl (meth)acrylate may provide improved mechanical properties and thermal stability to the copolymer of the present invention. Component (b) may be composed of isobornyl acrylate (IBOA) and / or isobornyl methacrylate (IBOMA). In one embodiment, component (b) is composed of IBOA. In another embodiment, component (b) is composed of IBOMA. While IBOMA may be preferred over IBOA due to concerns that IBOA is an allergen, IBOMA has less skin irritation and a higher Tg, which may contribute to high modulus and retention when used in a cured product.

[0029] Component (c) comprises at least one carboxyl-functionalized (—COOH) ethylenically unsaturated monomer. The carboxyl-functionalized ethylenically unsaturated monomer may be an ethylenically unsaturated monocarboxylic or dicarboxylic acid, such as (meth)acrylic acid. The presence of component (c) may improve the adhesion of the copolymer when used in adhesives, particularly those intended for application to polar substrates, such as metal or glass substrates. However, the presence of component (c) may result in copolymers with high acid values, which may be corrosive to metal surfaces, especially in high temperature and / or high humidity environments, making them unsuitable for use in electronics. For example, when a copolymer with high acid values ​​is used as an adhesive for electronics, it may corrode circuitry and indium tin oxide (ITO) conductive layers. Therefore, the weight percentage of component (c) present in the monomer mixture may be adjusted depending on the end-use application of the copolymer of the present invention.

[0030] In some embodiments, the monomer mixture may be substantially free of component (c). "Substantially free of component (c)" means that the monomer mixture contains less than 0.5% by weight, less than 0.2% by weight, less than 0.1% by weight, less than 0.01% by weight, less than 0.001% by weight, or even 0% by weight of component (c), based on the total weight of the monomer mixture. As discussed in the preceding paragraph, copolymers prepared from components (a), (b), and optional component (d) without component (c) may be suitable for use in adhesives for electronics.

[0031] Alternatively, when the monomer mixture comprises component (c), the amount of component (c) may be from 0.5 to 5% by weight, in particular from 0.5 to 3% by weight, or from 1 to 2% by weight, relative to the total weight of the monomer mixture.

[0032] Component (d) consists of at least one ethylenically unsaturated monomer other than those described in components (a), (b) and (c).Examples of suitable monomers that may be included in component (d) are (meth)acrylamides; alpha-olefins; vinyl ethers; allyl ethers; styrene and other aromatic vinyl compounds; diesters of ethylenically unsaturated dicarboxylic acids such as maleic acid, fumaric acid, mesaconic acid, citraconic acid, aconitic acid or itaconic acid; C1-C20 alkyl (meth)acrylates, excluding 2-octyl (meth)acrylate, 2-methylbutyl acrylate and 3-methylbutyl acrylate, such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl ... butyl (meth)acrylate, iso-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, iso-octyl (meth)acrylate, decyl (meth)acrylate and dodecyl (meth)acrylate; cyclic (meth)acrylates other than isobornyl (meth)acrylate, such as cyclohexyl (meth)acrylate, phenyl (meth)acrylate and 2-phenoxyethyl (meth)acrylate; N-vinylpyrrolidone; N-vinylcaprolactam; substituted (meth)acrylamides such as N-methyl (meth)acrylamide, N-ethyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N-cyclohexyl (meth)acrylamide, N-cyclopentyl (meth)acrylamide, N-methoxymethyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide, N,N-dibutyl (meth)acrylamide, N-butyl (meth)acrylamide, N, N-diethyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-octyl(meth)acrylamide, N-decyl(meth)acrylamide, N-dodecyl(meth)acrylamide, N-octadecyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N-tert-butyl(meth)acrylamide, N-isobutyl(meth)acrylamide, N,N,3,3-tetramethylacrylamide, N-phenyl(meth)acrylamide, N-(meth)acryloylmorpholine; and mixtures thereof.The selection of monomers in component (d) may be based on the desired characteristics of the copolymers of the present invention, such as Tg and functional groups.

[0033] In some embodiments, component (d) may contain at least one monomer selected from a crosslinking monomer or a functional monomer. The presence of a crosslinking monomer or a functional monomer is useful for preparing a copolymer with a high degree of crosslinking and excellent mechanical properties (such as its elongation resistance). When used in adhesives or coatings, a copolymer with a high degree of crosslinking can contribute to the water resistance or chemical resistance of the formed film.

[0034] Examples of crosslinking monomers include: ethylenically unsaturated monomers containing a carbonyl group (which can react with compounds containing at least two amino groups, preferably at least two hydrazide groups), such as diacetone (meth)acrylamide, 2-(acetoacetoxy)ethyl (meth)acrylate, 2-(acetoacetoxy)propyl (meth)acrylate, 3-(acetoacetoxy)propyl (meth)acrylate, 4-(acetoacetoxy)butyl (meth)acrylate, 2,3-di(acetoacetoxy)propyl (meth)acrylate, diacetone (meth)acrylate, acetonyl (meth)acrylate, allyl acetoacetate, vinyl acetoacetate, acetoacetamide, methyl vinyl ketone, ethyl vinyl ketone, butyl vinyl ketone, (meth)acrolein, crotonaldehyde and formylstyrene; - ethylenically unsaturated compounds containing hydroxyl groups (which can react with polyisocyanates), such as hydroxyalkyl(meth)acrylates (especially 2-hydroxyethyl(meth)acrylate or 2-hydroxypropyl(meth)acrylate) or N-hydroxyalkyl(meth)acrylamides (especially N-(2-hydroxyethyl)(meth)acrylamide, N-methylol(meth)acrylamide, N-methyl-N-(2-hydroxyethyl)(meth)acrylamide or N-ethyl-N-(2-hydroxyethyl)(meth)acrylamide); - ethylenically unsaturated compounds containing siloxane groups (which can react with copolymer chains containing siloxane groups), such as vinyltrimethoxysilane, vinyldimethoxymethylsilane, vinyltriethoxysilane, vinyltripropoxysilane, vinyltriisopropoxysilane, vinyltris(methoxyethoxy)silane, vinyltributoxysilane, vinyltriacetoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, methacryloxymethyltrimethoxysilane, 3-methacryloxypropyltris(2-methoxyethoxy)silane, vinyltrichlorosilane, vinylmethyldichlorosilane, vinyltris(2-methoxyethoxy)silane; - compounds containing at least two ethylenic unsaturations (which can react with copolymer chains containing ethylenic unsaturation), such as polyfunctional (meth)acrylates, polyvinyl monomers or compounds containing both (meth)acrylic and vinyl groups, more particularly allyl (meth)acrylate, diallyl (meth)acrylate, vinyl (meth)acrylate, divinylbenzene, ethylene glycol di(meth)acrylate, diallyl phthalate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol triallyl ether, dicyclopentenyl-6-oxyethyl (meth)acrylate, glycerol tri(meth)acrylate; and mixtures thereof.

[0035] Examples of functional monomers include: acetoxyethyl (meth)acrylate, - ethylenically unsaturated monomers having a phosphonic acid (-P(=O)(OH)2), phosphonate (-P(=O)(OR)2), sulfate (-S(=O)2OH), sulfonate (-S(=O)2OR) or phosphate (-OP(=O)(OR)2) group, where each R is independently a counterion, a hydrogen atom, or an optionally substituted hydrocarbyl phosphate or phosphonate functional group; - ethylenically unsaturated monomers containing ureido functional groups, - ethylenically unsaturated monomers with amine functionality, and mixtures thereof.

[0036] In some embodiments, the monomer mixture may be substantially free of component (d).

[0037] In the practice of the present invention, the copolymers of the present invention can be obtained by conventional polymerization methods, including, but not limited to, solvent polymerization, suspension or emulsion polymerization, solventless bulk polymerization, and radiation polymerization, including processes using ultraviolet light, electron beam, and gamma radiation. Polymerization initiators, particularly thermal or photoinitiators, can be used in amounts effective to polymerize the comonomers.

[0038] The copolymers of the present invention are preferably not prepared by suspension or emulsion polymerization, i.e. in an aqueous medium in the presence of one or more polymerization initiators and optionally one or more surfactants.

[0039] The copolymers of the present invention are preferably prepared by solvent polymerization, i.e., in an organic solvent in the presence of one or more polymerization initiators.

[0040] Examples of suitable organic solvents include hydrocarbon organic solvents such as n-hexane, n-heptane, cyclohexane, methylcyclohexane, benzene, toluene, or xylene; halogenated organic solvents such as trichloroethylene or methylchloroform; esters such as ethyl acetate, isopropyl acetate, n-butyl acetate, or sec-butyl acetate; and mixtures thereof. The amount of organic solvent can be adjusted so that the amount of copolymer is 10 to 80% by weight, preferably 20 to 50% by weight, based on the total amount of copolymer and organic solvent.

[0041] Examples of suitable polymerization initiators include azo compounds and peroxides. Azo compounds are compounds containing an azo group of the formula -N=N-. An example of a suitable azo compound is azobisisobutyronitrile (AIBN). Peroxide compounds are compounds containing a peroxide group of the formula -OO-. The peroxide compounds can be selected from hydrogen peroxide, hydroperoxides (ROOH), dialkyl or alkylaryl peroxides (ROO-R'), peracids (RC(=O)-OOH), peroxyesters (RC(=O)-OO-R'), diacyl peroxides (RC(=O)-OOC(=O)-R'), peroxycarbonates (ROC(=O)-OOC(=O)-O-R'), peroxyketals (from the reaction of a ketone with hydrogen peroxide or hydroperoxide), and mixtures thereof, where R and R' are independently aliphatic, cycloaliphatic, or aromatic groups. Examples of suitable peroxide compounds are dibenzoyl peroxide, dilauroyl peroxide, diisopropyl peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, cyclohexanone peroxide, methyl ethyl ketone peroxide, tert-butyl peroxyoctoate, tert-butyl peroxybenzoate, dicumyl peroxide, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, tert-butyl peroxymaleate, and mixtures thereof.

[0042] The copolymer of the present invention may be a single-stage copolymer. As used herein, "single-stage copolymer" refers to a copolymer prepared in a single polymerization step, as opposed to a "multi-stage copolymer," which is prepared using multiple sequential polymerization steps. Thus, a single-stage copolymer may exhibit a single phase and a single Tg.

[0043] The copolymer may have a bio-renewable carbon content (%BRC) of greater than 10, preferably greater than 30, more preferably greater than 50, and even more preferably greater than 70.

[0044] The weight-average molecular weight (Mw) of the copolymer of the present invention is not particularly limited, but is preferably 20,000 to 120,000 g / mol, preferably 30,000 to 100,000 g / mol, and more preferably 40,000 to 90,000 g / mol, from the viewpoints of handleability, viscosity, mechanical properties, etc. The molecular weight distribution (Mw / Mn) of the copolymer of the present invention, i.e., the weight-average molecular weight (Mw) / number-average molecular weight (Mn), may be in the range of 1.01 to 5.5, preferably 1.05 to 5.

[0045] The number average molecular weight (Mn), weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the copolymers can be measured by gel permeation chromatography (GPC) using polystyrene standards, for example, as described in the Examples section below.

[0046] The glass transition temperature (Tg) of the copolymer of the present invention calculated according to the Fox equation is not particularly limited, but is preferably within the range of −40° C. to 50° C., preferably −30° C. to 40° C., and more preferably −20° C. to 30° C. The calculation formula is as follows:

[0047]

number

[0048] (Where W1 to W n is the mass fraction of each monomer used to obtain the copolymer; T g1 From T gn are the glass transition temperatures (in degrees Kelvin "K") of the homopolymers corresponding to the respective monomers.

[0049] composition The compositions of the present invention comprise the copolymers disclosed above.

[0050] In a first embodiment of the composition of the present invention, the composition comprises: (A) a copolymer of the present invention, and (B) at least one crosslinking agent selected from polyfunctional amines, hydrazides, aziridines, isocyanates, oxazoles, and epoxy compounds; Includes.

[0051] The composition may be a thermosetting composition, i.e., a composition that cures upon heating. In particular, the composition may be applied to the surface of a substrate and cured by heating (e.g., oven drying). Once cured, the composition may exhibit desired physical properties, such as adhesive properties.

[0052] At least one crosslinking agent (B) can be incorporated into the thermosetting composition to enhance its bonding strength. Crosslinking agents (B) include polyfunctional amines, hydrazides, aziridines, isocyanates, oxazoles, or epoxy compounds. An example of a polyfunctional aziridine compound is 1,1'-(1,3-phenylenedicarbonyl)-bis-(2-methylaziridine) (CAS No. 7652-64-4). Common polyfunctional isocyanate compounds include trimethylolpropane toluene diisocyanate, toluene diisocyanate, and others known in the art. The crosslinking agent can be added to the copolymer after polymerization and activated by heat during drying of the coated substrate. The composition may be particularly suitable for use as a PSA.

[0053] In a second embodiment of the composition of the present invention, the composition comprises: (A) a copolymer of the present invention; (C) at least one ethylenically unsaturated compound, and optionally (D) at least one free radical initiator; Includes.

[0054] The composition may be a radiation-curable composition, i.e., a composition that cures upon exposure to radiation, such as heat, UV energy, visible light, and / or an electron beam. In particular, the radiation-curable composition may be cured by at least one of the following processes: (1) exposing the composition to UV energy and / or visible light; (2) exposing the composition to an electron beam; (3) initiating polymerization through the use of redox-generated radicals; (4) initiating polymerization through the use of heat-generated radicals; or a combination thereof.

[0055] The first and second embodiments can be combined with each other.

[0056] The composition of the present invention may contain from 5 to 90% by weight, preferably from 10 to 90% by weight, in particular from 10 to 80% by weight, of component (A) relative to the total weight of the composition.

[0057] The composition of the present invention may contain from 5 to 90% by weight, preferably from 10 to 90% by weight, in particular from 20 to 90% by weight, of component (C) relative to the total weight of the composition.

[0058] In radiation curable compositions, component (C) may comprise or consist of at least one (meth)acryloyl-functionalized monomer or oligomer.

[0059] As used herein, the term "(meth)acryloyl-functionalized monomer" refers to a monomer containing a (meth)acryloyl group, particularly an acryloyl group. The term "(meth)acryloyl-functionalized oligomer" refers to an oligomer containing a (meth)acryloyl group, particularly an acryloyl group. The term "(meth)acryloyl group" refers to an acrylate group (-O-CO-CH=CH), a methacrylate group (-O-CO-C(CH)=CH), an acrylamide ...

[0060] [ka]

[0061] and methacrylamide group

[0062] [ka]

[0063] Includes.

[0064] Component (C) may comprise or consist of (C1) at least one (meth)acryloyl-functionalized monomer. Component (C1) may also comprise a mixture of (meth)acryloyl-functionalized monomers.

[0065] The molecular weight of the (meth)acryloyl-functionalized monomer may be less than 600 g / mol, in particular from 80 g / mol to 550 g / mol, more in particular from 100 g / mol to 500 g / mol.

[0066] The (meth)acryloyl-functionalized monomer may have from 1 to 6 (meth)acryloyl groups, especially from 1 to 4 (meth)acryloyl groups.

[0067] In particular, component (C1) may comprise or consist of at least one mono(meth)acryloyl-functionalized monomer. The mono(meth)acryloyl-functionalized monomer may advantageously function as a reactive diluent, reducing the viscosity of the composition of the present invention. Furthermore, it may impart viscoelasticity or weatherability to the cured composition, which is required for adhesion.

[0068] Component (C1) may be, but is not limited to, mono-(meth)acrylate esters of aliphatic alcohols (wherein the aliphatic alcohol may be linear, branched, or alicyclic, and may be a mono-alcohol, dialcohol, or polyalcohol, but only one hydroxyl group is esterified with (meth)acrylic acid); mono-(meth)acrylate esters of aromatic alcohols (such as phenol, alkylated phenols); mono-(meth)acrylate esters of alkylaryl alcohols (such as benzyl alcohol); mono-(meth)acrylate esters of glycol oligomers and glycol polymers, such as diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol, and polypropylene glycol; monoalkyl ethers of glycols and octadecyl ethers; mono-(meth)acrylate esters of alkoxylated (e.g., ethoxylated and / or propoxylated) aliphatic alcohols (wherein the aliphatic alcohol may be linear, branched, or alicyclic and may be a mono-alcohol, dialcohol, or polyalcohol, but where only one hydroxyl group of the alkoxylated aliphatic alcohol is esterified with (meth)acrylic acid); mono-(meth)acrylate esters of alkoxylated (e.g., ethoxylated and / or propoxylated) aromatic alcohols (such as alkoxylated phenols); caprolactone mono(meth)acrylate, and mixtures thereof.

[0069] Specific examples of mono(meth)acrylate functionalized compounds include methyl(meth)acrylate; ethyl(meth)acrylate; n-propyl(meth)acrylate; n-butyl(meth)acrylate; sec-butyl(meth)acrylate; isobutyl(meth)acrylate; 2-methylbutyl(meth)acrylate; 3-methylbutyl(meth)acrylate; n-hexyl(meth)acrylate; 4-methyl-2-pentyl(meth)acrylate; 2-ethylhexyl(meth)acrylate; n-octyl(meth)acrylate; isooctyl(meth)acrylate. Acrylate;Isononyl (meth)acrylate;n-Decyl (meth)acrylate;Isodecyl (meth)acrylate;2-Propylheptyl (meth)acrylate;n-Dodecyl (meth)acrylate;Tridecyl (meth)acrylate;Tetradecyl (meth)acrylate;Hexadecyl (meth)acrylate;C18-Alkyl (meth)acrylate;C22-Alkyl (meth)acrylate;2-Hydroxyethyl (meth)acrylate;2-Hydroxypropyl (meth)acrylate and 3-Hydroxypropyl (meth)acrylate;2-Methacrylate Ethoxyethyl (meth)acrylate; 2-Ethoxyethyl (meth)acrylate; 2-Ethoxypropyl (meth)acrylate and 3-Ethoxypropyl (meth)acrylate; Tetrahydrofurfuryl (meth)acrylate; Isobornyl (meth)acrylate; 2-(2-Ethoxyethoxy)ethyl (meth)acrylate; Cyclohexyl (meth)acrylate; tert-Butylcyclohexyl (meth)acrylate; Glycidyl (meth)acrylate; Benzyl (meth)acrylate; 2-Phenoxyethyl (meth)acrylate; Isobornyl Nyl (meth)acrylate;Tricyclodecanemethanol mono(meth)acrylate;Phenol (meth)acrylate;Nonylphenol (meth)acrylate;Cyclic trimethylolpropane formal (meth)acrylate;Trimethylcyclohexanol (meth)acrylate;Diethylene glycol monomethyl ether (meth)acrylate;Diethylene glycol monoethyl ether (meth)acrylate;Diethylene glycol monobutyl ether (meth)acrylate;Triethylene glycol monoethyl ether (meth)acrylateIncluded are methoxypolyethylene glycol (meth)acrylate; (3-(2-hydroxyalkyl)oxazolidinone (meth)acrylate; (2,2-dimethyl-1,3-dioxolan-4-yl)methyl (meth)acrylate; (2-ethyl-2-methyl-1,3-dioxolan-4-yl)methyl (meth)acrylate; (1,3-dioxan-5-yl (meth)acrylate; (1,3-dioxolan-4-yl)methyl (meth)acrylate; glycerol carbonate (meth)acrylate; alkoxylated (i.e., ethoxylated and / or propoxylated) derivatives thereof; and combinations thereof;

[0070] Preferably, component (C1) is 2-ethylhexyl (meth)acrylate, tert-butyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, dicyclopentadienyl (meth)acrylate, tricyclodecanemethanol mono(meth)acrylate, tetrahydrofuran Mono(meth)acrylate functionalized monomers having a branched alkyl group or a cyclic group, such as difurfuryl (meth)acrylate, cyclic trimethylolpropane formyl (meth)acrylate (also known as (5-ethyl-1,3-dioxan-5-yl)methyl (meth)acrylate, (2,2-dimethyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, and (2-ethyl-2-methyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, can advantageously increase the Tg and adhesion of the cured composition compared to monofunctional alkyl (meth)acrylates having a linear alkyl group with the same number of carbon atoms.

[0071] Component (C1) may be, but is not limited to, (meth)acrylamide; N-methyl(meth)acrylamide; N-ethyl(meth)acrylamide; isopropyl(meth)acrylamide; N,N-diethyl(meth)acrylamide; N-cyclohexyl(meth)acrylamide, N-cyclopentyl(meth)acrylamide; N-butoxymethyl(meth)acrylamide; N,N-dibutyl(meth)acrylamide; N-butyl(meth)acrylamide; diacetone(meth)acrylamide; N-(N,N-dimethylamino)ethyl(meth)acrylamide; N,-(N,N-dimethylamino)propyl(meth)acrylamide, N,N-diethyl(meth)acrylamide; N,N-dimethyl N-isobutyl(meth)acrylamide, N,N,3,3-tetramethylacrylamide; N-methylol(meth)acrylamide; N-[2-hydroxyethyl](meth)acrylamide; N-phenyl(meth)acrylamide; acryloylmorpholine; and combinations thereof.

[0072] In a preferred embodiment, component (C1) may comprise or consist of a mixture of at least one mono(meth)acrylate-functionalized monomer and at least one mono(meth)acrylamide-functionalized monomer.

[0073] Component (C) may comprise 0 to 100% by weight, particularly 5 to 100%, more particularly 10 to 100%, and even more particularly 20 to 100% by weight, of component (C1), based on the total weight of component (C). In particular, component (C) may comprise 5 to 50% by weight, or 10 to 50% by weight, or 15 to 50% by weight, or 20 to 50% by weight, of component (C1), based on the total weight of component (C). Alternatively, component (C) may comprise 50 to 100% by weight, or 55 to 100% by weight, or 60 to 100% by weight, or 65 to 100% by weight, of component (C1), based on the total weight of component (C).

[0074] Component (C) may comprise or consist of (C2) at least one (meth)acrylate-functionalized oligomer. Component (C2) may comprise or consist of a mixture of (meth)acrylate-functionalized oligomers.

[0075] (Meth)acrylate-functionalized oligomers can be selected to enhance the flexibility, strength and / or modulus, among other characteristics, of cured polymers prepared using the compositions of the present invention.

[0076] The (meth)acrylate-functionalized oligomer may have from 1 to 18 (meth)acrylate groups, particularly from 2 to 6 (meth)acrylate groups, more particularly from 2 to 6 acrylate groups.

[0077] The number average molecular weight of the (meth)acrylate-functionalized oligomer may be from 2,000 g / mol to 100,000 g / mol, preferably from 3,000 g / mol to 90,000 g / mol, and more preferably from 4,000 g / mol to 80,000 g / mol. The number average molecular weight of the oligomer can be measured by gel permeation chromatography (GPC) using polystyrene standards.

[0078] The (meth)acrylate-functionalized oligomers include (meth)acrylate-functionalized urethane oligomers (sometimes referred to as "urethane (meth)acrylate oligomers," "polyurethane (meth)acrylate oligomers," or "carbamate (meth)acrylate oligomers"), (meth)acrylate-functionalized epoxy oligomers (sometimes referred to as "epoxy (meth)acrylate oligomers"), (meth)acrylate-functionalized polyether oligomers (sometimes referred to as "polyether (meth)acrylate oligomers"), and the like. The (meth)acrylate-functionalized oligomer may be selected from the group consisting of (meth)acrylate-functionalized polydiene oligomers (sometimes referred to as "polydiene (meth)acrylate oligomers"), (meth)acrylate-functionalized polycarbonate oligomers (sometimes referred to as "polycarbonate (meth)acrylate oligomers"), and (meth)acrylate-functionalized polyester oligomers (sometimes referred to as "polyester (meth)acrylate oligomers"), and mixtures thereof.

[0079] In particular, component (C2) may comprise or consist of a (meth)acrylate-functionalized urethane oligomer, more preferably an acrylate-functionalized urethane oligomer.

[0080] Advantageously, the (meth)acrylate-functionalized oligomer comprises a (meth)acrylate-functionalized urethane oligomer having two (meth)acrylate groups, more preferably an acrylate-functionalized urethane oligomer having two acrylate groups.

[0081] (Meth)acrylate-functionalized urethane oligomers suitable for use in the compositions of the present invention can be prepared by reacting a polyisocyanate (e.g., an aliphatic, cycloaliphatic, and / or aromatic diisocyanate or triisocyanate) with a polyol (e.g., a polyester polyol, a polyether polyol, a polycarbonate polyol, a polycaprolactone polyol, a polyorganosiloxane polyol, or a polydiene polyol, such as a polybutadiene polyol, or a combination thereof) to form an isocyanate-functionalized oligomer, followed by reaction with a hydroxyl-functionalized (meth)acrylate (e.g., hydroxyethyl (meth)acrylate) to provide terminal (meth)acrylate groups. For example, the (meth)acrylate-functionalized urethane oligomer may contain two, three, four, or more (meth)acrylate functional groups per molecule. Other sequences of addition may be repeated to prepare (meth)acrylate-functionalized urethane oligomers, as known in the art. For example, a hydroxyl-functionalized (meth)acrylate may be first reacted with a polyisocyanate to give an isocyanate-functionalized (meth)acrylate, which is then reacted with a polyol. Alternatively, all components may be combined and reacted simultaneously.

[0082] In a preferred embodiment, the (meth)acrylate-functionalized urethane oligomer contains hydrophobic moieties in its backbone derived from polyolefins such as polypropylene, polybutadiene, hydrogenated polybutadiene, polyisoprene, or hydrogenated polyisoprene. The hydrophobic moieties can be introduced by using polypropylene polyol, polybutadiene polyol, hydrogenated polybutadiene polyol, polyisoprene polyol, or hydrogenated polyisoprene polyol to prepare the (meth)acrylate-functionalized urethane oligomer. Examples of hydrophobic (meth)acrylate-functionalized urethane oligomers are commercially available from Sartomer (particularly CN8899 NS, a difunctional urethane acrylate oligomer). The addition of hydrophobic (meth)acrylate-functionalized urethane oligomers to radiation-curable compositions can improve the rebound properties of films formed therefrom.

[0083] Component (C) may contain 0 to 100% by weight, particularly 0 to 90%, more particularly 0 to 85%, and even more particularly 0 to 80% by weight of component (C2), based on the total weight of component (C). In particular, component (C) may contain 0 to 50%, or 0 to 40%, or 0 to 30%, or 0 to 25% by weight of component (C2), based on the total weight of component (C). Alternatively, component (C) may contain 50 to 100%, or 55 to 90%, or 60 to 90%, or 65 to 90% by weight of component (C2), based on the total weight of component (C).

[0084] In contrast to tackifiers conventionally used in adhesive compositions (e.g., styrenated terpenes, hydrocarbon resins, and polyisobutylene), the copolymers of the present invention exhibit excellent compatibility with (meth)acrylate-functionalized monomers and oligomers. Thus, the radiation-curable compositions of the present invention have excellent compatibility with raw materials and can be used to obtain optically clear adhesives or coatings.

[0085] The composition of the invention may contain from 0 to 5% by weight, in particular from 1 to 3% by weight, of component (D) relative to its total weight.

[0086] The at least one free radical initiator (D) may be a photoinitiator, i.e., an initiator that generates radicals upon exposure to electromagnetic radiation, such as UV or visible light. Examples of photoinitiators include benzoin, benzoin ether, acetophenone, α-hydroxyacetophenone, benzil, benzil ketal, anthraquinone, phosphine oxide, acylphosphine oxide, α-hydroxyketone, phenylglycoxylate, α-aminoketone, benzophenone, thioxanthone, xanthone, acridine derivatives, phenazene derivatives, quinoxaline derivatives, triazine compounds, benzoyl formate, aromatic oximes, metallocenes, acylsilyl or acylgermanyl compounds, camphorquinone, their polymeric derivatives, and mixtures thereof. Among these, phosphine oxides are preferred. Examples of commercially available photoinitiators include those sold by Sartomer under the trade names SpeedCure TPO and SpeedCure XKm.

[0087] Alternatively, the at least one free radical initiator (D) may be a peroxide initiator. The peroxide initiator may be activated by heating or by a reducing agent. The peroxide initiator may be as defined above for the polymerization initiator. Examples of suitable reducing agents may be tertiary amines, such as N,N-dimethylaniline, N-(4-methoxyphenyl)pyrrolidine and N-phenyldiethanolamine, sodium sulfite, or sodium metabisulfite.

[0088] The radiation-curable compositions described herein can be applied and cured using conventional methods, such as UV light from a medium-pressure mercury lamp directly through the layer. Alternatively, electron beam (EB) radiation can be used to cure the radiation-curable adhesive composition. When EB radiation is used, the composition can be substantially free of a free-radical initiator (D).

[0089] In the radiation-curable composition of the present invention, the content of each raw material can be appropriately controlled according to factors such as the target use and physical property requirements. For example, the radiation-curable composition may contain the following ingredients relative to its total mass: 10 to 90% by weight, in particular 60 to 80% by weight, of (A) the copolymer according to the invention, 10 to 90% by weight, in particular 20 to 40% by weight, of (C1) at least one mono(meth)acryloyl-functionalized monomer, 0 to 5% by weight, in particular 1 to 3% by weight, of (D) at least one free radical initiator It may comprise or consist of:

[0090] In particular, the total weight of components (A), (C1) and (D) may represent 100% of the weight of the radiation-curable composition.

[0091] Alternatively, the radiation curable composition may contain, based on its total weight, 5 to 90% by weight, in particular 10 to 35% by weight, of (A) the copolymer according to the invention, 5 to 90% by weight, in particular 15 to 35% by weight, of (C1) at least one mono(meth)acryloyl-functionalized monomer, 5 to 90% by weight, in particular 30 to 74% by weight, of (C2) at least one (meth)acrylate-functionalized urethane oligomer, and 0 to 5% by weight, in particular 1 to 3% by weight, of (D) at least one free radical initiator It may comprise or consist of:

[0092] For example, the radiation curable composition may contain, based on its total weight, 10 to 90% by weight, in particular 10 to 35% by weight, of (A) the copolymer according to the invention, 10 to 90% by weight, in particular 15 to 35% by weight, of (C1) at least one mono(meth)acryloyl-functionalized monomer, 10 to 90% by weight, in particular 30 to 74% by weight, of (C2) at least one (meth)acrylate-functionalized urethane oligomer, and 0 to 5% by weight, in particular 1 to 3% by weight, of (D) at least one free radical initiator It may comprise or consist of:

[0093] In particular, the total weight of components (A), (C1), (C2) and (D) may represent 100% of the weight of the radiation curable composition.

[0094] In a third embodiment of the composition according to the present invention, the composition may comprise the copolymer of the present invention and a solvent (organic solvent or water). In one case where an organic solvent is used as the solvent, the addition of an organic solvent can help adjust the viscosity of the composition to reach the desired viscosity for the application. In another case where water is used as the solvent, the composition is an aqueous composition (or emulsion, latex, or aqueous dispersion). The copolymer in the composition typically accounts for 5 to 90% by weight, preferably 10 to 75% by weight, based on the total weight of the composition. In dry weight, the copolymer typically accounts for 5 to 50% by weight, preferably 20 to 40% by weight, based on the total weight of the composition. The composition may further comprise an additional binder, such as a silicone resin or silicate. When the solvent is an organic solvent, the composition can be used as a solvent-based coating composition or a solvent-based adhesive composition. When the solvent is water, the composition can be used as a water-based coating composition or a water-based adhesive composition.

[0095] This third embodiment can be combined with the first and / or second embodiment described above.

[0096] The copolymers and compositions of the present invention can be used in a variety of applications, including automotive, consumer electronics, and construction, as two typical examples of which are discussed in detail below: in the preparation of adhesives or coatings, or as adhesives or coatings.

[0097] Use in adhesives As used herein, "adhesive" or "adhesives" means a substance that is applied between two separate objects to bond them and resist separation. Adhesives are sometimes known as glues, sealants, cements, mortars, putties, rubber cements, or pastes.

[0098] The compositions of the present invention can be used directly as adhesives or can be used in the preparation of adhesives together with other ingredients.

[0099] When used as an adhesive, the composition of the present invention may be first applied to the surface of a first substrate using conventional coating methods (such as roll, brush coating, flow, dip, spin, spray, knife, spread, wire, gravure, doctor blade, and die coating). The applied thickness may vary depending on factors such as the specific application, the viscosity of the composition, and the nature of the substrate. A second substrate is then coupled to the surface, resulting in the creation of a high-strength bond connecting the two substrates. If necessary, the composition may be cured under certain conditions (including temperature, time, radiation, etc.) to form an adhesive film laminated between the two substrates. Each of the first and second substrates may be made of wood, metal, glass, cement, paper, textile, leather, plastic, foam, or brick.

[0100] The adhesive or adhesive film formed from the composition of the present invention may exhibit pressure-sensitive properties and may have excellent adhesive strength and bonding power.

[0101] The adhesive film formed from the composition of the present invention can have good mechanical properties. In some embodiments, the composition of the present invention can have a peel strength of 8 to 35 N / cm, preferably 10 to 30 N / cm, on either a glass substrate or a stainless steel substrate when forming an adhesive film.

[0102] The adhesive film formed from the composition of the present invention may have good optical performance and be suitable for use as an optically clear adhesive. The transmittance of the adhesive film measured by spectrometry may be 90% or more, preferably 95% or more. The turbidity of the film measured by spectrometry may be 0.8% or less, preferably 0.5% or less. In particular, the transmittance and turbidity can be measured by a spectrophotometer, for example, as described in the Examples section below.

[0103] Adhesive films formed from the compositions of the present invention may exhibit low dielectric constants, making them suitable for use in electronics.

[0104] When used as an adhesive, the compositions of the present invention may further comprise materials commonly used in the art to impart or enhance the tack of adhesives, such as tackifiers. Examples of tackifiers include rosin, rosin esters of glycerol or pentaerythritol, hydrogenated rosin, polyterpene resins such as those polymerized from beta-pinene, coumarone-indene resins, and polymerized C5 and C9 petroleum fractions. Furthermore, when used as an adhesive, the compositions of the present invention may further comprise other additives to modify the physical properties of the adhesive. These additives include plasticizers, pigments, tackifiers, fillers such as glass or polymeric bubbles or beads (which may be foamed or non-foamed), hydrophobic or hydrophilic silica, calcium carbonate, glass or synthetic fibers, blowing agents, reinforcing agents, reinforcing materials, flame retardants, antioxidants, and stabilizers. The additives are added in amounts sufficient to achieve the desired final physical properties. If other additives are used, a maximum of about 40% by weight, preferably less than 30% by weight, more preferably less than 5% by weight, based on the dry weight of the total copolymer (A) may be suitable.

[0105] Use in coatings The term "coating" or "coatings" is understood to mean a substance applied to a substrate in the form of a film having a thickness sufficient to modify the appearance of the substrate, in particular its optical properties, and / or to protect its surface, in particular against scratches, moisture, dirt or light. The term "coating composition" does not include adhesive compositions and may include paints, protective coatings, varnishes and ink compositions, but is not limited to this list. Substrates for coating may be made of wood, metal, glass, cement, paper, textiles, leather, plastic, foam, or brick.

[0106] The compositions of the present invention can be used directly as a coating or can be used in the preparation of a coating together with other ingredients.

[0107] When used as a coating, the composition of the present invention may be applied to the surface of a first substrate using conventional coating methods (e.g., roll, brush coating, flow, dipping, spin, spray, knife, spread, wire, gravure, doctor blade, and die coating) and cured under certain conditions (including temperature, time, radiation, etc.) to form a coating film. The thickness of the coating film may vary depending on factors such as the particular application, the viscosity of the composition, and the nature of the substrate, and may be uniform or non-uniform. The cured coating film may be a dry film having a desired hardness.

[0108] The coating film formed by the composition of the present invention may have good optical transparency. The transmittance of the film measured by a spectrophotometer may be 90% or more, preferably 95% or more. The turbidity of the film measured by a spectrophotometer may be 0.8% or less, preferably 0.5% or less. In particular, the transmittance and turbidity can be measured by a spectrophotometer, for example, as described in the Examples section below.

[0109] The composition may further comprise additives selected from, for example, one or more pigments; one or more powdered fillers; one or more pH adjusters; one or more dispersants and / or wetting agents, such as sodium, potassium or ammonium polyphosphates and naphthalene sulfonates; one or more thickeners, such as xanthan and cellulose derivatives; one or more antifoaming agents; one or more film-forming agents; one or more antifreeze agents; one or more flame retardants, in particular organophosphorus compounds, magnesium hydroxide or aluminum hydroxide; one or more biocides; and mixtures thereof.

[0110] Goods The present application also provides an article comprising at least one film formed from the composition of the present invention, which may be an electronic device, such as a flexible or foldable display device or touch screen. [Example]

[0111] The following examples illustrate the invention without limiting it.

[0112] Materials and Methods The following compounds were used in the examples:

[0113] [Table 1]

[0114] The following methods were used to measure various physical properties in the examples.

[0115] Molecular weight and molecular weight distribution The number average molecular weight (Mn), weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the copolymer were measured by gel permeation chromatography (GPC) using polystyrene standards. The GPC measurement conditions are shown below. Model: Agilent Technologies 1200 series - Column: Edipse XDB-C18 / Edipse Plus C18 - Eluent: tetrahydrofuran (THF) - Flow rate: 0.45mL / min - Temperature: 40℃ - Sample injection volume and concentration: 5 μL, 10 mg / mL - Detection: RI (differential refractometer) - Data collection and processing system: Waters Empower3

[0116] Tg The Tg of the copolymer was calculated according to the Fox equation, which is given below:

[0117]

number

[0118] (Where W1 to W n is the mass fraction of each monomer used to obtain the copolymer; T g1 From T gn are the glass transition temperatures (in degrees Kelvin "K") of the homopolymers corresponding to the respective monomers.

[0119] Transmittance and Turbidity The transmittance and turbidity were measured using a spectrophotometer (HunterLab ColorQuest XE). Sample preparation: The above composition was coated on a float glass substrate with a thickness of 50 μm, and then dried or exposed to UV irradiation of 225 wm / cm 2 . 2 , 2000mj / cm 2 The coating was cured by exposure to a mercury lamp at 1000 kJ / cm 3 .

[0120] Peel strength It is also called peel strength, peel force, or adhesive strength.

[0121] For the peel strength on stainless steel substrates, samples were prepared by laminating a SUS304 plate, a 100 μm thick adhesive, and a 100 μm thick PET film. If the adhesive composition was a UV-curable composition, the sample was exposed to UV light. The sample was then stored at room temperature for 24 hours. Peel strength was measured using a tensile tester (Shimadzu AGS-X) at 23 °C by peeling at a 180° angle at a rate of 300 / min.

[0122] Regarding the peel strength on a glass substrate, the same procedure as above was carried out except that a glass plate was used instead of the SUS304 plate.

[0123] holding power Measurements were performed in accordance with ASTM D4498. The adhesive tape was 50 micrometers thick and 25 mm wide, and was mounted on a stainless steel (SUS304) board. A 1000 g load was suspended from the adhesive tape, and the temperature was raised to 25°C and 70°C. The drop time was measured at 25°C and 70°C, respectively.

[0124] Aging test A hygrothermal test was performed at 85°C and 85% relative humidity (RH) using a BGD897 / 100C from BIUGED.

[0125] Preparation of 2-OA Sec-octyl alcohol (260.0 g), acrylic acid (158.0 g), heptane (198.0 g), p-methoxyphenol (1.35 g), and methylsulfonic acid (6.0 g) were added to a four-neck round-bottom flask and mixed thoroughly at room temperature. The four-neck round-bottom flask was fitted with a reflux condenser, dry air was blown into it, and the mixture was slowly heated to reflux temperature (i.e., 100-120°C). The mixture was refluxed for 10 hours, after which the water yield and acid value were sampled every hour. The reaction was stopped when the water yield reached 39 mL and the acid value of the mixture was less than 23 mg KOH / g. A clear, oily mixture containing 2-OA, acrylic acid, and heptane was obtained.

[0126] Preparation of 2-MBA 2-Methyl-1-butanol (260.0 g), acrylic acid (234.0 g), heptane (197.0 g), p-methoxyphenol (1.4 g), and methylsulfonic acid (7.0 g) were added to a four-neck round-bottom flask and mixed thoroughly at room temperature. The four-neck round-bottom flask was fitted with a reflux condenser, dry air was blown into it, and the mixture was slowly heated to reflux temperature (i.e., 100-120°C). The mixture was refluxed for 10 hours, after which the water yield and acid value were sampled every hour. The reaction was stopped when the water yield reached 56 mL and the acid value of the mixture was less than 24 mg KOH / g. A clear, oily mixture containing 2-MBA, acrylic acid, and heptane was obtained.

[0127] Preparation of 3-MBA 3-Methyl-1-butanol (260.0 g), acrylic acid (234.0 g), heptane (197.0 g), p-methoxyphenol (1.4 g), and methylsulfonic acid (7.0 g) were added to a four-neck round-bottom flask and mixed thoroughly at room temperature. The four-neck round-bottom flask was fitted with a reflux condenser, dry air was blown into it, and the mixture was slowly heated to reflux temperature (i.e., 100-120 °C). The mixture was refluxed for 10 hours, after which the water yield and acid value were sampled every hour. The reaction was stopped when the water yield reached 56 ml and the acid value of the mixture was less than 24 mg KOH / g. A clear, oily mixture containing 3-MBA, acrylic acid, and heptane was obtained.

[0128] (Examples 1 to 11) Copolymer The following Examples 1 to 11 relate to the preparation of copolymers, of which Examples 1 to 7 are according to the invention, while Examples 8 to 11 are comparative examples.

[0129] (Example 1 (according to the present invention)) Toluene (52.0 g) and ethyl acetate (8.0 g) were added to a four-neck round-bottom flask, mixed thoroughly at room temperature, stirred, and heated to 85°C. 2-OA (50.0 g), IBOA (56.5 g), AIBN (0.5 g), and toluene (20.0 g) were combined and added at a steady rate under dry nitrogen within 90 minutes. The temperature was maintained at 85°C for a short time, then heated to 95°C and held for 60 minutes after the addition of the 2-OA, IBOA, AIBN, and toluene mixture. A mixture of AIBN (0.2 g) and toluene (2.0 g) was then added. The mixture was held at 95°C for 2 hours and then sampled for GPC. After cooling and filtration, a clear oil was obtained.

[0130] (Examples 2 to 11) The process was repeated according to Example 1, with the composition of the monomer feed set as shown in Table 2, Table 3 and Table 4.

[0131] The physical property data of the copolymers prepared in Examples 1 to 11, including % BRC, molecular weight and molecular weight distribution, and Tg, are shown in Tables 2 to 4.

[0132] The copolymers obtained in Examples 1 to 11 can be used directly as adhesives. One copolymer (prepared in Examples 1 to 11) was applied to a substrate (SUS304 plate or glass layer) to a thickness of 100 μm and covered with a 100 μm PET film. After storing at room temperature for 24 hours, the intermediate layer formed an adhesive film. According to the test methods described above, the transmittance, turbidity, and peel strength of the adhesive film were measured and are listed in Tables 2 to 4.

[0133] [Table 2]

[0134] [Table 3]

[0135] [Table 4]

[0136] According to the results shown in Tables 2 to 4, the use of at least one of 2-OA, 2-MBA, and 3-MBA in combination with at least one of IBOA or IBMOA allows the preparation of copolymers with high %BRC values ​​(>70) and good optical (almost transparent) and mechanical properties (good peel strength on substrates such as glass and SUS304).

[0137] (Examples 12 to 22) Radiation curable composition The following Examples 12 to 15 relate to radiation-curable compositions according to the present invention. For each of Examples 11 to 14, the raw materials were mixed in the weight parts shown in Table 5, coated onto a PET film, and then laminated with a PET release film. After exposure to UV light, the PET release film was removed to obtain a cured adhesive film. For peel strength testing, the cured adhesive film was manually laminated to glass or SUS304 stainless steel using a hand roller, applying strong pressure to the exposed surface of the cured adhesive film. The optical properties and peel strength of the cured adhesive film are shown in Table 5. In the raw materials section of Table 5, E1, E2, E4, and E7 refer to the copolymers prepared in Examples 1, 2, 4, and 7, respectively. The UV exposure dose was 225 mW / cm. 2 , 2000mJ / cm 2 UV exposure was carried out using a mercury lamp at .

[0138] [Table 5]

[0139] The following Examples 16 to 22 relate to radiation-curable compositions using the urethane acrylate oligomer CN8899 NS, with Examples 16 to 19 being in accordance with the present invention and Examples 20 to 22 being comparative examples using a conventional tackifier.

[0140] For each of Examples 16 to 22, the raw materials were mixed in the weight parts shown in Table 6, coated onto a PET film, and laminated with a PET release film. After exposure to UV light, the PET release film was removed to obtain a cured adhesive film. For peel strength testing, the cured adhesive film was manually laminated to a glass or stainless steel (SS) substrate using a hand roller, applying heavy pressure to the exposed surface of the cured adhesive film. The optical properties and peel strength of the cured adhesive film are shown in Table 6. In the raw materials section of Table 6, E1, E2, E4, and E7 refer to the copolymers prepared in Examples 1, 2, 4, and 7, respectively. The UV exposure dose was 225 mW / cm. 2 , 2000mJ / cm 2 UV exposure was performed by using a mercury lamp at 1000 kJ / cm 3 .

[0141] [Table 6]

[0142] As shown in Table 6, when the copolymer of the present invention was used as a tackifier in a radiation-curable adhesive composition, it had good compatibility with the urethane acrylate oligomer (CN8899 NS) in the system. Furthermore, the cured adhesive film exhibited good optical properties and adhesive strength. However, conventional tackifiers showed poor compatibility with the urethane acrylate oligomer (CN8899 NS). Due to the poor compatibility, the systems of Comparative Examples 20 to 22 cannot be used as optically clear adhesives.

Claims

1. A copolymer obtained by polymerization of a monomer mixture, the monomer mixture comprising, relative to its total mass, (a) from 45 to 95% by weight, in particular from 45 to 90% by weight, from 48 to 80% by weight, or from 50 to 70% by weight, of at least one monomer selected from the group consisting of 2-octyl (meth)acrylate, 2-methylbutyl acrylate, 3-methylbutyl acrylate, and mixtures thereof; (b) 5 to 55% by weight, in particular 10 to 55% by weight, 20 to 52% by weight, or 30 to 50% by weight, of isobornyl (meth)acrylate, (c) 0 to 5% by weight, particularly 0 to 2% by weight, 0 to 1% by weight, or even 0% by weight, of at least one carboxyl-functionalized ethylenically unsaturated monomer, and (d) 0 to 30% by weight, in particular 0 to 20% by weight, 0 to 10% by weight, or 0 to 5% by weight, of at least one ethylenically unsaturated monomer other than (a), (b), and (c). A copolymer comprising:

2. 2. The copolymer of claim 1 having a bio-renewable carbon content (%BRC) greater than 10, preferably greater than 30, more preferably greater than 50, even more preferably greater than 70.

3. 3. The copolymer according to claim 1 or 2, having a weight average molecular weight of from 20,000 to 120,000 g / mol, preferably from 30,000 to 100,000 g / mol, more preferably from 40,000 to 90,000 g / mol.

4. 4. The copolymer according to any one of claims 1 to 3, having a glass transition temperature of the copolymer, calculated according to the Fox equation, in the range of from -40°C to 50°C, preferably from -30°C to 40°C, more preferably from -20°C to 30°C.

5. The component (a) is, relative to its total mass, (a1) 1 to 99% by weight of 2-octyl (meth)acrylate, and (a2) 1 to 99% by weight of 2-methylbutyl acrylate and / or 3-methylbutyl acrylate 5. The copolymer according to claim 1, consisting of

6. 6. The copolymer of claim 1, wherein the monomer mixture is substantially free of component (c).

7. A composition comprising the copolymer of any one of claims 1 to 6.

8. (A) a copolymer according to any one of claims 1 to 6, and (B) at least one crosslinking agent selected from polyfunctional amines, hydrazides, aziridines, isocyanates, oxazoles, and epoxy compounds; 8. The composition of claim 7, comprising:

9. (A) a copolymer according to any one of claims 1 to 6; (C) at least one ethylenically unsaturated compound, and optionally (D) at least one free radical initiator; 9. The composition of claim 7 or 8, comprising:

10. Component (C) is (C1) at least one (meth)acryloyl-functionalized monomer, in particular at least one mono(meth)acryloyl-functionalized monomer, more in particular a mono(meth)acrylate-functionalized monomer having a branched alkyl group or a cyclic group; 10. The composition of claim 9, comprising or consisting of:

11. Component (C) is (C2) at least one (meth)acrylate-functionalized oligomer, in particular at least one (meth)acrylate-functionalized urethane oligomer, more in particular at least one (meth)acrylate-functionalized urethane oligomer containing in its main chain a hydrophobic moiety derived from a polyolefin, a polydiene or a hydrogenated polydiene; 11. The composition according to claim 9 or 10, comprising or consisting of:

12. 10 to 90% by weight, in particular 60 to 80% by weight, of (A) the copolymer according to any one of claims 1 to 6, 10 to 90% by weight, in particular 20 to 40% by weight, of (C1) at least one mono(meth)acryloyl-functionalized monomer, 0 to 5% by weight, in particular 1 to 3% by weight, of (D) at least one free radical initiator 12. The composition of any one of claims 9 to 11, comprising:

13. 10 to 90% by weight, in particular 10 to 35% by weight, of (A) the copolymer according to any one of claims 1 to 6, 10 to 90% by weight, in particular 15 to 35% by weight, of (C1) at least one mono(meth)acryloyl-functionalized monomer, 10 to 90% by weight, in particular 30 to 74% by weight, of (C2) at least one (meth)acrylate-functionalized urethane oligomer, and 0 to 5% by weight, in particular 1 to 3% by weight, of (D) at least one free radical initiator 12. The composition of any one of claims 9 to 11, comprising:

14. 14. A composition according to claim 7 or any one of claims 8 to 13, comprising a copolymer according to any one of claims 1 to 6 and a solvent, the solvent being an organic solvent or water.

15. 15. Use of a composition according to any one of claims 7 to 14 in the preparation of or as an adhesive or coating.

16. 15. An article comprising at least one film formed by curing the composition of any one of claims 7 to 14, wherein the at least one film has a transmittance of 95% or greater and a haze of 0.5% or less.

17. 17. The article of claim 16, which is an electronic device, such as a flexible or foldable display device or touch screen.

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