Adhesives with high biomass content and optically clear adhesives

Abstract

The curable composition comprises: a (meth)acrylate functionalized polyurethane polymer that is the reaction product of a reaction mixture comprising: a polyisocyanate; a polyol; and a hydroxyl reactive or isocyanate reactive (meth)acrylate; at least one ethylenically unsaturated monomer having a polar content that is a vinyl functional polar monomer or a (meth)acrylate represented by the formula CH2=CR 1 -(CO)-O-R 2 where R 1 is H or a methyl group; (CO) is a carbonyl group C=O; R 2 is -R 3 -(X) p or a polyether group; R 3 is a linear or branched p+1 valent aliphatic group having at least two carbon atoms; X is a polar group comprising a hydroxyl group, a nitrogen containing group, or an acid group; and p is an integer of 1 or greater; menthyl (meth)acrylate represented by the structure OO R where R is H or a methyl group; and an initiator.

Description

Summary of the Invention

[0001] In one aspect, this document provides curable compositions comprising: (Meth)acrylate-functionalized polyurethane polymers, wherein the (meth)acrylate-functionalized polyurethane polymers are reaction products comprising a reaction mixture containing the following substances: Polyisocyanates; Polyols; and Hydroxyl-reactive or isocyanate-reactive (meth)acrylates; At least one olefinically unsaturated monomer having a polar content, wherein the olefinically unsaturated monomer is a vinyl-functionalized polar monomer or (meth)acrylate represented by the following formula: CH2=CR 1 -(CO)-OR 2 Where R 1 It is an H or methyl group; (CO) is a carbonyl group C=O; R 2 Yes -R 3 -(X) p Group or polyether group; R 3 It is a straight-chain or branched aliphatic group with at least two carbon atoms and a p+1 valence. X is a polar group containing a hydroxyl group, a nitrogen-containing group, or an acid group; and p is an integer of 1 or greater; Menthol esters of (meth)acrylate represented by the following structure:

[0002] Where R is an H or methyl group; and

[0003] Initiator.

[0004] On the other hand, articles comprising such curable compositions are provided.

[0005] As used in this article: The term "alkyl group" and the prefix "alkane-" have only C-C and CH bonds and include both straight-chain and branched groups as well as cyclic groups. In some embodiments, unless otherwise specified, the alkyl group has up to 30 carbons (in some embodiments, up to 20, 15, 12, 10, 8, 7, 6, or 5 carbons). The cyclic group can be monocyclic or polycyclic and, in some embodiments, has 3 to 10 cyclic carbon atoms and other alkyl substituents; The term "acrylic" refers to acrylic and methacrylic polymers, oligomers, and monomers. The term "direct bond to" refers to bonding via a single covalent bond; The term "radical polymerization" refers to radical homopolymerization and / or radical copolymerization (i.e., with different monomers / oligomers). The term “bio-content” refers to the amount of biomass in a product, taking into account the four key components: carbon, hydrogen, oxygen, and nitrogen; bio-based content is expressed as a percentage of the total weight of the product under discussion.

[0006] The term "bio-based" refers to, for example, compositions consisting primarily of one or more substances derived from living matter (biomass) and existing naturally or synthetically, or it can refer to products prepared using biomass methods. By a strict definition, many common materials (such as paper, wood, and leather) could be called bio-based, but the term generally refers to modern materials that have undergone more extensive processing. Materials derived from biomass sources include bulk chemicals, platform chemicals, solvents, polymers, and biocomposites (some materials fall into more than one category).

[0007] The term "high biomass content" refers to, for example, a composition having a biomass content of at least 14% (16%, 18%, 20%, or 22% in some embodiments).

[0008] The term “(meth)acryl” refers to acryl (also known in the art as acryloyl / acrylyl) and / or methacryl (also known in the art as methacryloyl / methacrylyl)).

[0009] Terms such as “a,” “an,” and “the / described” are not intended to refer to a single entity, but rather to encompass general categories, which may be illustrated with specific examples. The terms “a,” “an,” and “the / described” are used interchangeably with the term “at least one (kind).”

[0010] The phrase "including at least one of..." followed by a list means including any item in the list or any combination of two or more items in the list.

[0011] The terms “curable” and “curable” refer to polymers linked together by covalent chemical bonds, usually through cross-linked molecules or groups, to form a network polymer.

[0012] Therefore, in this disclosure, the terms "cured" and "crosslinked" are used interchangeably. Cured or crosslinked polymers are generally characterized by insolubility, but can be swollen in the presence of a suitable solvent.

[0013] Unless otherwise stated, all numerical ranges include their endpoints and the non-integer values ​​between them (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).

[0014] The features and advantages of this disclosure will be further understood when considered in conjunction with the specific embodiments and the appended claims. Attached Figure Description

[0015] Figure 1 This is a graph showing the rheological data of Embodiment 2 (“Ex-2”) and Comparative Example (“CEx”) of this disclosure. Detailed Implementation

[0016] This disclosure provides a curable composition comprising a (meth)acrylate-functionalized polyurethane polymer, the (meth)acrylate-functionalized polyurethane polymer being a reaction product comprising a reaction mixture containing the following substances: Polyisocyanates; Polyols; and Hydroxyl-reactive or isocyanate-reactive (meth)acrylates; At least one olefinically unsaturated monomer having a polar content, wherein the olefinically unsaturated monomer is a vinyl-functionalized polar monomer or (meth)acrylate represented by the following formula: CH2=CR 1 -(CO)-OR 2 Where R 1 It is an H or methyl group; (CO) is a carbonyl group C=O; R 2 Yes -R 3 -(X) p Group or polyether group; R 3 It is a straight-chain or branched aliphatic group with at least two carbon atoms and a p+1 valence. X is a polar group containing a hydroxyl group, a nitrogen-containing group, or an acid group; and p is an integer of 1 or greater; Menthol esters of (meth)acrylate represented by the following structure:

[0017] Where R is an H or methyl group; and

[0018] Initiator.

[0019] In some embodiments, the curable composition, when cured in the form of a layer, forms a pressure-sensitive adhesive layer or a heat-activated adhesive layer with a haze value of less than 1%, preferably less than 0.5%.

[0020] In some embodiments, the (meth)acrylate-functionalized polyurethane polymer is a reaction product comprising aliphatic polyisocyanates, polyols, and hydroxyl-reactive or isocyanate-reactive (meth)acrylates.

[0021] In some embodiments, the (meth)acrylate-functionalized polyurethane polymer is a reaction product comprising a reaction mixture of a polyisocyanate, a polyester polyol, and a hydroxyl-reactive or isocyanate-reactive (meth)acrylate.

[0022] In some embodiments, the (meth)acrylate-functionalized polyurethane polymer has a number-average molecular weight of at least 4000 g / mol.

[0023] In some embodiments, the olefinic unsaturated monomer with a polar content is 2-hydroxyethyl (meth)acrylate.

[0024] In some implementations, aliphatic polyisocyanates are represented by the following formula: (OCN-L) n - R 4 Where R 4 It is an n-valent aliphatic group; L is a single bond or an alkylene linkage group; and n is an integer of at least 2.

[0025] In some implementations, the polyester polyol is represented by the following formula: (HO) m - R 5 Where R 5 It is an m-valent aliphatic group with polyester bonds, and m is an integer of at least 2.

[0026] In some implementations, the polyester polyol is a dimerized fatty acid-based polyester polyol.

[0027] In some embodiments, hydroxyl-reactive or isocyanate-reactive (meth)acrylates are represented by the following formula: CH2=CR 1-(CO)-OR 2 -Z Where R 1 It is an H or methyl group; (CO) is a carbonyl group C=O; R 2 It is a straight-chain or branched alkylene group having at least 2 carbon atoms; Z is a hydroxyl group or an isocyanate group.

[0028] In some preferred embodiments, the (meth)acrylate menthol ester is the (meth)acrylate L-menthol ester.

[0029] In some embodiments, menthol methacrylate is derived from L-menthol, and in some preferred embodiments, menthol methacrylate is derived from bio-based L-menthol.

[0030] In some embodiments, the curable composition may contain at least one other free radical polymerizable bio-based monomer, such as, for example, ethyl (meth)acrylate, benzyl (meth)acrylate, stearyl (meth)acrylate, lauryl (meth)acrylate, 2-octyl (meth)acrylate, or combinations thereof.

[0031] In some embodiments, the composition may comprise at least one photoinitiator, alone or in combination with other radical initiators known to those skilled in the art, which is activated by light (typically ultraviolet (UV) lamps), but other light sources such as LED lamps, xenon flash lamps, and lasers may also be used where the photoinitiator is appropriately selected. Available photoinitiators include those known to be suitable for photocuring radical polyfunctional (meth)acrylates. Examples of suitable photoinitiators include benzoin and its derivatives such as α-methylbenzoin; α-phenylbenzoin; α-allylbenzoin; α-benzylbenzoin; benzoin ethers, such as benzoyl dimethyl ketal (e.g., purchased at OMNIRAD BDK from IGM Resins USA Inc., St. Charles, Illinois), benzoin methyl ether, benzoin ethyl ether, benzoin n-butyl ether; acetophenone and its photoinitiators.

[0032] Other useful photoinitiators include phosphine oxides. Preferred phosphine oxide photoinitiators with functional wavelengths in the range of about 365 nm to about 450 nm are acylphosphine oxides and diacylphosphine oxides. In a preferred embodiment, the photoinitiator initiates free radical polymerization of the composition upon exposure to photochemical radiation with wavelengths from 365 nm to 450 nm.

[0033] Commercially available phosphine oxide photoinitiators capable of free radical initiation when irradiated in the wavelength range of 365 nm to 450 nm include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (IRGACURE 819, Ciba Specialty Chemicals, Tarrytown, NY) or Omnirad 819, IGM Resins BV Waalwijk, Netherlands), (2,4,6-trimethylbenzoyl)diphenylphosphine oxide (Omnirad TPO, IGM Resins BV Waalwijk, Netherlands), and bis(2,6-dimethoxybenzoyl)-(2,4,4-trimethylpentyl)phosphine oxide (CGI 403, Ciba Specialty Chemicals). Chemicals), a mixture of bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide and 2-hydroxy-2-methyl-1-phenylpropane-1-one by weight in a 25:75 ratio (IRGACURE 1700, Ciba Chemicals), a mixture of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and 2-hydroxy-2-methyl-1-phenylpropane-1-one by weight in a 1:1 ratio (DAROCUR 4265, Ciba Chemicals), and ethyl 2,4,6-trimethylbenzylphenylphosphonite (LUCIRIN LR8893X, BASF Corp., Charlotte, NC).

[0034] In some embodiments, the curable composition may contain additives such as, for example, silane adhesion promoters, UV absorbers, tackifiers, rheology modifiers, free radical stabilizers, corrosion inhibitors, or combinations thereof.

[0035] On the other hand, this document provides articles, which include: Substrate, the substrate having a first main surface and a second main surface; and A pressure-sensitive adhesive layer or a heat-activated adhesive layer is disposed on at least a portion of the second main surface of the substrate, and the pressure-sensitive adhesive layer or the heat-activated adhesive layer is a reaction product of a curable composition of any of the embodiments described above. In some embodiments, the substrate includes an optically transparent substrate comprising a polymer film or sheet.

[0036] In some embodiments, the pressure-sensitive adhesive layer has a thickness of 10 micrometers to 1 millimeter. In some embodiments, the biomass content of the adhesive layer is at least 14% by weight.

[0037] In some aspects, the curable composition comprises at least one (meth)acrylate-functionalized polyurethane polymer. The at least one (meth)acrylate-functionalized polyurethane polymer is a reaction product comprising at least one aliphatic polyisocyanate, at least one polyester polyol, and a hydroxyl-functionalized or isocyanate-functionalized (meth)acrylate. Each of these components of the reaction mixture is described in more detail below.

[0038] Suitable (meth)acrylate-functionalized polyurethane polymers may include aromatic urethane acrylates, aliphatic urethane acrylates, aromatic / aliphatic urethane acrylates, and combinations thereof. Many (meth)acrylate-functionalized polyurethane polymers are commercially available. Suitable examples of (meth)acrylate-functionalized polyurethane polymers are available from: Arkema, King of Prussia, Pennsylvania; SOLTECH LTD., Yangsan, South Korea; Nippon Soda Co. Ltd., Chiyoda, Japan; Dymax, Torrington, Connecticut; and Eternal Materials Co., Ltd., Taiwan, China.

[0039] Typically, polyurethane polymers are formed by reacting at least one polyisocyanate with at least one polyol to form a prepolymer. The prepolymer is either isocyanate-functionalized or hydroxyl-functionalized, depending on the ratio of at least one polyisocyanate to at least one polyol. The prepolymer is then end-capped by reacting with hydroxyl-functionalized or isocyanate-functionalized acrylates, methacrylates, or combinations thereof.

[0040] In some embodiments, at least one aliphatic polyisocyanate has Formula 1: (OCN-L) n -A Formula 1 Where A is an n-valent aliphatic group, L is a single bond or alkylene linkage group; n is an integer of 2 or greater.

[0041] Examples of diisocyanates include: aromatic diisocyanates (e.g., 2,6-toluene diisocyanate; 2,5-toluene diisocyanate; 2,4-toluene diisocyanate; m-phenylene diisocyanate; p-phenylene diisocyanate; methylene bis(o-chlorophenylene diisocyanate); methylene diphenyl-4,4'-diisocyanate; polycarbodiimide-modified methylene diphenylene diisocyanate; (4,4'-diisocyanate-3... 3',5,5'-Tetraethyl)diphenylmethane; 4,4'-diisocyanate-3,3'-dimethoxybiphenyl (o-dimethoxyaniline diisocyanate); 5-chloro-2,4-toluene diisocyanate; and 1-chloromethyl-2,4-diisocyanate, aromatic-aliphatic diisocyanates (e.g., m-phenylenediamine diisocyanate and tetramethyl-m-phenylenediamine diisocyanate); aliphatic diisocyanates (e.g., 1,4-di... Butane isocyanate; 1,6-hexane diisocyanate; 2-methyl-1,5-pentamethylene diisocyanate; 1,12-dodecane diisocyanate); alicyclic diisocyanates (e.g., methylene dicyclohexene-4,4'-diisocyanate; 3-isocyanomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophenone diisocyanate); 2,2,4-trimethylhexyl diisocyanate; 1,4-cyclohexanebis(methylene) Polyisocyanates, 1,3-bis(isocyanatomethyl)cyclohexane; and cyclohexene-1,4-diisocyanates; polymers or oligomers (e.g., polyoxyethylene, polyester, polybutadiene, etc.) terminated by two isocyanate functional groups (e.g., toluene-2,4-diisocyanate-terminated polyoxypropylene glycol dicarboxylate); polyisocyanates commercially available from Covestro (Pittsburgh, PA) under the trade names MONDUR or DESMODUR (e.g., DESMODUR XP7100 and DESMODUR 3300); and combinations thereof.

[0042] Of particular advantage are aliphatic diisocyanates. Aliphatic diisocyanates are generally observed to offer superior weather resistance compared to their aromatic counterparts. Particularly preferred substances include dicyclohexylmethane diisocyanate, isoflavone diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, tetramethylxylene diisocyanate (TMXDI), 1,4-cyclohexanebis(methylene isocyanate), 1,3-bis(isocyanomethyl)cyclohexane, 2-methyl-1,5-pentamethylene diisocyanate, 1,12-dodecane diisocyanate, and copolymers and mixtures thereof. In selected embodiments, the diisocyanate comprises at least one ring in its structure, i.e., it contains a cyclic structure.

[0043] In some embodiments, at least one aliphatic polyisocyanate of formula 1 comprises a diisocyanate, wherein A is an alkylene group having at least 6 carbon atoms, L is a single bond, and n is an integer 2.

[0044] Examples of particularly suitable polyisocyanates include liquid alicyclic diisocyanates, such as hexamethylene diisocyanate and isophorone diisocyanate, which are commercially available under the trade name “DESMODUR” (such as DESMODUR W, DESMODUR H, DESMODUR I) from Covestro, Leverkusen, Germany, or under the trade name “VESTANAT” (such as VESTANAT TMDI (a mixture of 2,2,4- and 2,4,4-trimethyl-hexamethylene diisocyanate), VESTANAT IPDI) from Evonik Corporation, Theodore, Alabama, or Vencorex Chemicals, Freeport, TX, Texas.

[0045] Polyols used in polyurethane synthesis include, for example, polyester polyols, polyether polyols, polycaprolactone polyols, polycarbonate polyols, polyolefin polyols, fatty acid dimer diols, and copolymers and mixtures thereof. Examples of suitable polyols include materials commercially available under the trade name DESMOPHEN from Covestro LLC (Pittsburgh, PA) of Pittsburgh, Pennsylvania. Polyols can be polyester polyols (e.g., DESMOPHEN C1100, C1200, 850, and 1700, or under the trade name FOMREZ from Lanxess AG (Cologne, Germany) of Cologne, Germany, or SREPANPOL from Stepan Company (Northfield, IL) of Northfield, Illinois; polyether polyols (e.g., DESMOPHEN 1262BD, 1110BD, 1111BD, or under the trade name KURARAY). Materials P-500, P-1010, P-2010, P-3010, P-4010, P-5010, P-6010, P-2011, P-520, P-1020, P-2020, P-1012, P-2012, P-530, P-2030, and P-2050 were purchased from Kuraray Co., Ltd. (Tokyo, Japan); polycaprolactone polyols, such as caprolactone polyols purchased under the trade name CAPA from Ingevity (North Charleston, SC), South Carolina (e.g., CAPA). 2043, 2054, 2100, 2121, 2200, 2201, 2200A, 2200D, 2100A, 3031, 3091, and 3051; polycarbonate polyols (e.g., purchased under the trade names PC-1122, PC-1167, and PC-1733 from Picassian Polymers (Boston, MA)); polycarbonate polyols purchased under the trade names DESMOPHENC2102, 2202, C XP 2716, and C XP 2613 from Covestro LLC; and polycarbonate polyols purchased under the trade names KURARAY C-590, C-1090, C-2090, and C-3090 from Kuraray Corporation); polyolefin polyols (e.g., purchased under the trade name NISSO-PB from Nippon Soda Corporation). (Co.,LTD) of polyolefin polyols).

[0046] The reaction mixture also comprises at least one polyester polyol. In some embodiments, the at least one polyester polyol has Formula 2: (HO) m -B Formula 2 Where B is an m-valent aliphatic group having at least one polyester bond, and m is an integer of 2 or greater.

[0047] In some embodiments, at least one polyester polyol of formula 2 comprises a polyester diol with a molecular weight of at least 500, wherein B is a divalent aliphatic group having at least one polyester bond, and m is an integer of 2.

[0048] In some embodiments, the polyester diol is prepared by the condensation reaction of a diacid and a diol, wherein at least one of the diacid and the diol comprises an alkylene group having at least 12 carbon atoms. In some embodiments, it may be desirable for the alkylene group having at least 12 carbon atoms to be a branched alkylene group.

[0049] Examples of particularly suitable polyester polyols include dimerized fatty acid-based polyester polyols under the trade name "PRIPLAST" from Cargill, Minneapolis, MN, such as PRIPLAST 3196, PRIPLAST 3190, PRIPLAST 3238, PRIPLAST 3187, PRIPLAST 3188, PRIPLAST 3186, PRIPLAST 1838, PRIPLAST 3172, PRIPLAST 3197, PRIPLAST 3286, and PRIPLAST 3293, as well as combinations thereof.

[0050] In some implementations, it may be desirable to include polyols of formula 7: D-((E-OH)-Y) a Formula 7 Where D is an α-valent aromatic, aliphatic, or epoxy alkyl group, E is an epoxy alkyl linking group, Y is a (meth)acrylate group, and α is an integer of 2 or greater. The advantage of including this type of monomer is that the (meth)acrylate group is already linked to the polyol, and therefore does not need to react with the compound of formula 3 described below.

[0051] Examples of suitable compounds of Formula 7 are DENACOL ACRYLATE materials commercially available from Nagase ChemteX Corporation in the forms DA-911, DA-920, DA-931, DA-212, DA-214, DA-250, DA-721 and DM-201.

[0052] Typically, if used, the polyol of Formula 7 is a minor component of the reaction mixture, and additional polyols as described above are also present in the reaction mixture.

[0053] In some embodiments, it is desirable that the prepolymer formed by the reaction of polyisocyanate and polyol has a functionality of less than 2. It is well known that the reaction of diol and diisocyanate forms a linear bifunctional prepolymer. To form a prepolymer with a functionality of less than 2, at least some of the reactants must have a functionality of less than 2. In some embodiments, the reaction mixture contains at least some monofunctionalized reactants such that the average functionality of the prepolymer is greater than 1 and less than 2. This prepolymer, upon reaction with a (meth)acrylate functionalized compound, forms a (meth)acrylate-functionalized polyurethane. Therefore, in these embodiments, the (meth)acrylate-functionalized polyurethane polymer has a functionality of greater than 1 and less than 2.

[0054] Examples of suitable monofunctional reactants are described by Equation 8: ZLK Formula 8 Where K is an aliphatic group, L is a single bond or alkylene linkage group, and Z is a hydroxyl group or isocyanate group.

[0055] The reaction mixture also contains at least one acrylate, methacrylate, or combination thereof of formula 3: CH2=CR 1 -(CO)-OR 2 -Z Formula 3 Where R 1 It is an H or methyl group, (CO) is a carbonyl group C=O, R 2 Z is a straight-chain or branched alkylene group having at least two carbon atoms, and Z is an isocyanate-reactive group or a hydroxyl-reactive group. Examples of isocyanate-reactive groups include hydroxyl groups, acid groups, and amino groups. Examples of hydroxyl-reactive groups include isocyanate groups, carboxylic acid groups, and acid anhydrides. Typically, the Z group is an isocyanate group or a hydroxyl group.

[0056] As described above, the choice between a hydroxyl group and an isocyanate group for the Z group depends on the relative ratio of the polyisocyanate and polyol components. If the polyisocyanate is present in excess to make the growth polymer is isocyanate-functionalized, then the acrylate or methacrylate is hydroxyl-functionalized (i.e., reacts with the isocyanate group). If the polyester polyol is present in excess to make the growth polymer is polyol-functionalized, then the acrylate or methacrylate is isocyanate-functionalized (i.e., reacts with the hydroxyl group).

[0057] The choice of components—acrylates, methacrylates, or a combination thereof—depends on the desired properties of the polyurethane polymer. Because acrylates and methacrylates react at different rates, the functionality of the polyurethane polymer provides a means of controlling the final properties of the resulting adhesive layer.

[0058] In some embodiments, at least one acrylate of formula 3, methacrylate, or combination thereof is a hydroxyl-functionalized (meth)acrylate, wherein R 1 It is an H or methyl group, (CO) is a carbonyl group C=O, R 2 Z is a straight-chain or branched alkylene group having at least 2 carbon atoms, and Z is a hydroxyl group.

[0059] Examples of particularly suitable hydroxyl-functionalized (meth)acrylates include HEA (2-hydroxyethyl acrylate), HEMA (2-hydroxyethyl methacrylate), HPA (hydroxypropyl acrylate), HPMA (hydroxypropyl methacrylate), HBA (4-hydroxybutyl acrylate), and HBMA (4-hydroxybutyl methacrylate).

[0060] The polymerization kinetics between polyisocyanates and polyols are typically accelerated by a suitable catalyst. In an exemplary embodiment, the (meth)acrylate-functionalized polyurethane polymer is prepared using any of a variety of known urethane catalysts, including dibutyltin dilaurate, dibutyltin diacetate, stannous octoate, triethylenediamine, zirconium catalysts, and bismuth catalysts.

[0061] In some embodiments, at least one (meth)acrylate-functionalized polyurethane polymer has a number-average molecular weight of at least 4000 g / mol.

[0062] In some embodiments, the olefinically unsaturated monomer having a polar content is an acrylic monomer and may contain hydroxyl groups. Acrylic monomers containing hydroxyl groups can be used, for example, to provide compositions that have improved adhesion to various plastics (in some embodiments, polyamide, acrylonitrile butadiene styrene (ABS), polycarbonate (PC), PC / ABS blends, polyvinyl chloride (PVC), poly(meth)methacrylate (PMMA)). Examples of suitable acrylic monomers containing hydroxyl groups include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2- and 3-hydroxypropyl acrylate, 2- and 3-hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, caprolactone mono(meth)acrylate (available under the trade name "SR-495B" from Sartomer) and other poly(e-caprolactone) mono[2-(meth)acryloyloxyethyl] esters, poly(e-caprolactone) mono[2-acryloyloxyethyl] esters, 2-hydroxy-3-alkoxy methacrylates, 2-hydroxy-3-alkoxy acrylates, and polyethylene glycol monoacrylates and methacrylates. Many acrylic monomers containing hydroxyl groups are available from commercial sources, such as 2-hydroxyethyl methacrylate (available from Evonik Performance Materials GmbH as VISIOMER HEMA 97 and HEMA 98) and hydroxypropyl methacrylate (available from Evonik Performance Materials GmbH as VISIOMER HPMA 97 and HPMA 98).

[0063] The compositions disclosed herein may also include other monofunctional free radical polymerizable monomers. Examples of usable monomers include 2-phenoxyethyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, alkoxylated lauryl (meth)acrylate, alkoxylated phenolic (meth)acrylate, alkoxylated tetrahydrofurfuryl (meth)acrylate, caprolactone (meth)acrylate, cyclotrimethylolpropane methyl acetal (meth)acrylate, ethylene glycol methyl ether (meth)acrylate, ethoxylated nonylphenol (meth)acrylate, isodecanyl (meth)acrylate, isooctyl (meth)acrylate, and (meth)acrylate. Octadecyl ester ((meth)acrylate stearyl ester), tetrahydrofurfuryl ester (meth)acrylate, tridecyl ester (meth)acrylate, tetrahydrofurfuryl ester (meth)acrylate, allyl ester (meth)acrylate, ethyl ester (meth)acrylate, n-propyl ester (meth)acrylate, n-butyl ester (meth)acrylate, isobutyl ester (meth)acrylate, n-hexyl ester (meth)acrylate, 2-ethylhexyl ester (meth)acrylate, n-octyl ester (meth)acrylate, n-decyl ester (meth)acrylate, n-dodecyl ester (meth)acrylate, and combinations thereof.

[0064] The purposes and advantages of this disclosure are further illustrated by the following non-limiting examples, but the specific materials and quantities cited in these examples, as well as other conditions and details, should not be considered as an excessive limitation of this disclosure.

[0065] Example

[0066] Unless otherwise specified or readily apparent from the context, all parts, percentages, ratios, etc., in the embodiments and the remainder of the specification are by weight.

[0067]

[0068] method

[0069] Method for determining the molecular weight of polyurethane: The molecular weight distribution of the compounds was characterized using gel permeation chromatography (GPC). The GPC instrument (purchased from Waters Corporation (Milford, Mass., USA)) included a high-performance liquid chromatography pump (model 1515HPLC), an autosampler (model 717), a UV detector (model 2487), and a refractive index detector (model 2410). The chromatogram was prepared using two 5-micron PL gelMIXED-D columns purchased from Varian Inc. (Palo Alto, Calif., USA). The polymer solution sample was prepared by dissolving the dried polymer sample in tetrahydrofuran at a concentration of 1.0% (w / v), and then passing the solution through VWR International (West Chester, Pa., USA). The sample was filtered through a 0.2-micron polytetrafluoroethylene filter (USA). The resulting sample was injected into a GPC and eluted at a rate of 1 mL / min using a column maintained at 35°C. The system was calibrated with polystyrene standards, and a calibration curve was established using linear least squares analysis.

[0070] Haze and Transmittance Testing: Transmittance measurements were performed in transmittance mode using an ULTRASCANPRO spectrophotometer (HunterLab, Reston, VA). For the sample being measured, a 0.1 mm thick adhesive coating layer between the peeled-coated carrier pads (Pad-1 / Pad-2 as described in the examples below) was cut into approximately 5 cm wide × 10 cm long pieces. One carrier pad was removed and the sample was laminated onto a sheet of clear 1 mm thick LCD glass (Swift Glass, Elmira Heights, New York). The second carrier pad was removed, and the sample was placed in the ULTRASCANPRO spectrophotometer to measure transmittance and haze through the glass / OCA assembly.

[0071] 180° Glass Peel Test: This peel adhesion test is similar to the test method described in ASTM D 3330-90, but uses a glass substrate instead of the stainless steel substrate described in that test. First, cured adhesive samples are laminated onto a 2 mil (51 micrometer) primed PET backing (obtained from Mitsubishi 3SAB). These are then cut into 1 cm strips and rolled onto the glass substrate using a Cheminstruments HR-100 roller. The test samples are conditioned in a CTH chamber for 18 hours before peel adhesion analysis using an IMass SP-2000 peel tester at a peel rate of 6 cm / min and a 180° peel angle.

[0072] Dynamic mechanical analysis was used to probe the modulus as a function of temperature and to determine the glass transition temperature (Tg) of the material. An 8 mm diameter × approximately 1 mm thick disk of the laminated assembly was placed between the probes of a DHR parallel plate rheometer (TA Instruments, New Castle, DE). Temperature scans were performed by increasing the temperature from -50 °C to 100 °C at a rate of 3 °C / min. During this increase, the sample oscillated at a frequency of 1 Hz and a strain of approximately 0.4%. During this scan, the shear storage modulus (G'), loss modulus (G''), and loss tangent were recorded at selected temperatures. The Tg of the material was also determined as the peak value of the loss tangent versus temperature curve.

[0073] Synthesis of L-menthol acrylate ("L-MTA") :

[0074] All amounts are relative to the amount of L-menthol. L-menthol (500 g, 3.20 mol, 1.00 wt%), acrylic acid (277 g, 3.84 mol, 1.20 wt%), phenothiazine (1.00 g, 2000 ppm), furfural (1.00 g, 2000 ppm), p-toluenesulfonic acid (pTSA, 5.75 g, 1.15 wt%), and cyclohexane (75.0 g, 15.0 wt%) were added to a 1 L round-bottom flask. The flask was equipped with a 30 cm Vigreux column and a Dean-Stark head, which was filled with cyclohexane containing 50 ppm furfural. Separate water was collected every 30 minutes to 1 hour throughout the reaction. First, the mixture was heated to 120 °C and reacted for 1 hour, where t0 was marked by reflux from the Dean-Stark head. Next, the set point was raised to 140 °C, and the mixture was allowed to react for 5.5 hours. Finally, the temperature was raised to 150°C and maintained for 2.5 hours, after which the mixture was cooled to room temperature. The conversion rate was determined by 1H-NMR and found to be generally >98%.

[0075] A Claisen head and a distillation condenser were used instead of a Dean-Stark head. A vacuum was applied, and the crude product was heated to 80°C for 1 hour. An ultimate vacuum of 5 mmHg was achieved. Next, the batch was heated from 115°C to 135°C to collect 545 g of the desired product (at 95°C–97°C under 5 mmHg), to which 10 mg of MEHQ (18 ppm) was added. A significant change in refractive index was observed when L-MTA was distilled compared to the lower boiling point compounds. The purity was determined to be >98% by weight by 1H-NMR.

[0076] Two batches of distilled L-MTA (545 g and 550 g) were combined and washed with 220 g of 2% sodium hydroxide aqueous solution. The organic phase was then washed with 220 g of deionized water until the aqueous phase was neutral (three times). Finally, the slightly turbid organic phase was filtered through filter paper to obtain clear L-MTA (1083 g, 80.1% yield). The purity was determined to be >98% by 1H-NMR and GC. 19 mg of MEHQ (expected 18 ppm) was added. The presence of 19 ppm MEHQ, 0.3 ppm phenothiazine, and 0.173% water was confirmed by standard QC tests. No residual furfural was detected in the sample. L-Menthol (C) was derived from bio-based L-menthol (C 10 H 20 L-MTA (C) made from O molecular weight 210.32 g / mol 13 H 22 O2 molecular weight 156.27) has a biomass content of 73.8% (i.e., 73.8% = 100% × (C) 10 H 19 Molecular weight of O / C13 H 22 O2 (molecular weight)

[0077] Synthesis of DL-menthol acrylate ("DL-MTA") :

[0078] All amounts are relative to the amount of DL-menthol. DL-menthol (500 g, 3.20 mol, 1.00 wt%), acrylic acid (277 g, 3.84 mol, 1.20 wt%), phenothiazine (1.00 g, 2000 ppm), furfural (1.00 g, 2000 ppm), p-toluenesulfonic acid (pTSA, 5.75 g, 1.15 wt%), and cyclohexane (75.0 g, 15.0 wt%) were added to a 1 L round-bottom flask. The flask was equipped with a 30 cm Vigreux column and a Dean-Stark head, which was filled with cyclohexane containing 50 ppm furfural. Separate water was collected every 30 minutes to 1 hour throughout the reaction. First, the mixture was heated to 120 °C and reacted for 1 hour, where t0 was marked by reflux from the Dean-Stark head. Next, the set point was raised to 140 °C, and the mixture was allowed to react for 5.5 hours. Finally, the temperature was raised to 150°C and maintained for 2.5 hours, after which the mixture was cooled to room temperature. The conversion rate was determined by 1H-NMR and found to be >98%.

[0079] A Claisen head and a distillation condenser were used instead of a Dean-Stark head. A vacuum was applied, and the crude product was heated to 80°C for 1 hour. An ultimate vacuum of 5 mmHg was achieved. Next, the batch was heated from 115°C to 135°C to collect 5425 g of the desired product (at 95°C–97°C under 5 mmHg), to which 10 mg of MEHQ (18 ppm) was added. A significant change in refractive index was observed compared to the lower boiling point compounds when DL-MTA was distilled. The purity was determined to be >98% by weight by 1H-NMR.

[0080] Two batches of distilled DL-MTA (542 g each) were combined and washed with 220 g of 2% sodium hydroxide aqueous solution. The organic phase was then washed with 220 g of deionized water until the aqueous phase was neutral (three times). Finally, the slightly turbid organic phase was filtered through filter paper to obtain clear DL-MTA (1076 g, 80.0% yield). The purity was determined to be 98.7% by weight by 1H-NMR. 20 mg of MEHQ (expected 19 ppm) was added. The presence of 21 ppm MEHQ, 0.2 ppm phenothiazine, and 0.160% water was confirmed by standard QC testing. No residual furfural was detected in the sample.

[0081] Synthesis of polyurethane (meth)acrylate ("PU") : 205.6 g of polyol, 15.77 g of DI, 0.22 g of BC, 0.08 g of BHT, and 50 g of MEK were added to a resin reaction vessel equipped with a mechanical stirrer, condenser, and air inlet. The solution was heated to up to 75 °C while stirring. The temperature was maintained at 75 ± 2 °C until the NCO content reached the theoretical NCO value, which was determined by back titration using standard dibutylamine. After obtaining the theoretical NCO value, the polyurethane was then end-capped by adding 2.88 g of HEMA. During the reaction, an additional 50 g of MEK was added to dilute the viscosity of the system. After the reaction was complete, 224 g of 2EHA was added, and the MEK was subsequently evaporated by a rotary evaporator to obtain a polyurethane (meth)acrylate (PU) in 2EHA at a weight ratio of 1:1 (Mn = 6300, obtained from GPC). The polyol PRIPLAST 3196 has a bio-based content of approximately 82%; the final PU (a 1:1 weight ratio of polyurethane to 2-EHA) has a bio-based content of approximately 38%.

[0082] Formulation of optically transparent adhesive and comparative examples ("CEx"), as well as test results of Examples 1 and 2.

[0083] All curable formulations were prepared by adding PU (as described in “Synthesis of Polyurethane (Meth)acrylate (“PU”), in a 1:1 weight ratio with 2-EHA), monomers, and photoinitiators in the weight percentages shown in Table 1. All materials were mixed together in an 8 oz amber wide-mouth flask and roller-mixed at room temperature for at least 8 hours until the formulation was completely homogeneous.

[0084] Table 1. Optically Transparent Adhesive Formulations

[0085] The obtained adhesive formulation was applied between two release liner pads (liner-1 and liner-2, obtained from SKC Haas) using a doctor blade coater to control the coating thickness (4 mils). The adhesive sample was tested at a total dosage of 2000 mJ / cm². 2 Cured under 405nm UV-LED light.

[0086] The cured samples were tested according to the above-described test methods, and their test results are summarized in Table 2. The compositions containing menthol acrylate exhibited good haze (<1%) and peel values ​​similar to those of the compositions containing IBOA.

[0087] Table 2. Test results of the examples

[0088] rheological data : The DMA curves (storage modulus G' and loss tangent) for CEx and Example 2 (“Ex-2”) are shown in Figure 1 Table 2 summarizes the Tg and 25°C G'. Compared with the compositions containing IBOA, the compositions containing L-MTA and DL-MTA exhibit slightly lower Tg and lower storage modulus.

[0089] The combination of PU and bio-derived (meth)acrylate L-menthol ester as a high Tg monomer can provide an optically clear adhesive with a biomass content of approximately 37.6%.

[0090] All references, patents, and patent applications cited in the above-mentioned patent-certified applications are incorporated herein by reference in their entirety. In the event of any inconsistency or contradiction between the incorporated references and this application, the information in the foregoing description shall prevail. The foregoing description, given to enable those skilled in the art to practice this disclosure protected by the claims, should not be construed as a limitation on the scope of this disclosure, which is defined by the claims and all their equivalents.

Claims

1. A curable composition, said curable composition comprising: (Meth)acrylate-functionalized polyurethane polymers, wherein the (meth)acrylate-functionalized polyurethane polymers are reaction products comprising a reaction mixture containing the following substances: Polyisocyanates; Polyols; and Hydroxyl-reactive or isocyanate-reactive (meth)acrylates; At least one olefinically unsaturated monomer having a polar content, said olefinically unsaturated monomer being a vinyl-functionalized polar monomer or (meth)acrylate represented by the following formula: CH2=CR 1 -(CO)-OR 2 Where R 1 It is an H or methyl group; (CO) is a carbonyl group C=O; R 2 Yes -R 3 -(X) p Group or polyether group; R 3 It is a straight-chain or branched aliphatic group with at least two carbon atoms and a p+1 valence. X is a polar group containing a hydroxyl group, a nitrogen-containing group, or an acid group; and p is an integer of 1 or greater; Menthol esters of (meth)acrylate represented by the following structure: Where R is an H or methyl group; and Initiator.

2. The curable composition according to claim 1, wherein the curable composition, when cured in the form of a layer, forms a pressure-sensitive adhesive layer or a heat-activated adhesive layer with a haze value of less than 1%, preferably less than 0.5%.

3. The curable composition according to claim 1, wherein the (meth)acrylate-functionalized polyurethane polymer is a reaction product comprising an aliphatic polyisocyanate, a polyol, and a hydroxyl-reactive or isocyanate-reactive (meth)acrylate.

4. The curable composition according to claim 1, wherein the (meth)acrylate-functionalized polyurethane polymer is a reaction product comprising a reaction mixture of a polyisocyanate, a polyester polyol, and a hydroxyl-reactive or isocyanate-reactive (meth)acrylate.

5. The curable composition according to claim 1, wherein the (meth)acrylate-functionalized polyurethane polymer has a number-average molecular weight of at least 4000 g / mol.

6. The curable composition according to claim 1, wherein the olefinic unsaturated monomer having a polar content is 2-hydroxyethyl (meth)acrylate.

7. The curable composition according to claim 1, wherein the polyisocyanate is represented by the following formula: (OCN-L) n - R 4 Where R 4 It is an n-valent aliphatic group. L is a single bond or an alkylene linkage group; and n is an integer of at least 2.

8. The curable composition according to claim 1, wherein the polyol is represented by the following formula: (HO) m - R 5 Where R 5 It is an m-valent aliphatic group with polyester bonds, and m is an integer of at least 2.

9. The curable composition according to claim 8, wherein the polyester polyol is a dimerized fatty acid-based polyester polyol.

10. The curable composition according to claim 1, wherein the hydroxyl-reactive or isocyanate-reactive (meth)acrylate is represented by the following formula: CH2=CR 1 -(CO)-OR 2 -Z Where R 1 It is an H or methyl group; (CO) is a carbonyl group C=O; R 2 It is a straight-chain or branched alkylene group having at least 2 carbon atoms; Z is a hydroxyl group or an isocyanate group.

11. The curable composition according to claim 1, wherein the (meth)acrylate menthol ester is L-menthol ester (meth)acrylate.

12. The curable composition according to claim 1, wherein the (meth)acrylate menthol ester is derived from L-menthol.

13. The curable composition of claim 11, wherein the (meth)acrylate menthol ester is derived from bio-based L-menthol.

14. The curable composition of claim 1, wherein the initiator comprises a photoinitiator.

15. The curable composition according to claim 1, wherein the curable composition further comprises at least one other free radical polymerizable bio-based monomer.

16. An article of manufacture comprising: A substrate having a first main surface and a second main surface; and A pressure-sensitive adhesive layer or a heat-activated adhesive layer, wherein the pressure-sensitive adhesive layer or the heat-activated adhesive layer is disposed on at least a portion of the second main surface of the substrate, and the pressure-sensitive adhesive layer or the heat-activated adhesive layer is a reaction product of the curable composition according to any one of claims 1 to 15.

17. The article of claim 16, wherein the substrate comprises an optically transparent substrate, the optically transparent substrate comprising a polymer film or a plate.

18. The article of claim 16, further comprising a silane adhesion promoter, a UV absorber, a tackifier, a rheology modifier, a free radical stabilizer, a corrosion inhibitor, or a combination thereof.

19. The article of claim 16, wherein the pressure-sensitive adhesive layer has a thickness of 10 micrometers to 1 millimeter.

20. The article of claim 16, wherein the biomass content of the adhesive layer is at least 14% by weight.

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