Curable compositions useful for obtaining non-sensitizing cured products

1 . A curable composition, comprising:

a) an acrylate-functionalized component comprising at least one acrylate-functionalized compound selected from the group consisting of i)-xi) and at least one acrylate-functionalized compound selected from the group consisting of xii)-xxiv):

i) acrylates of ethoxylated phenols containing 3 to 5 oxyethylene units per molecule;

ii) acrylates of propoxylated nonyl phenols containing 1 to 4 oxypropylene units per molecule;

iii) 6-methyl-1-heptanol acrylate or isooctyl acrylate;

iv) acrylates of methoxy polyethylene glycols, wherein the methoxy polyethylene glycols have a number average molecular weight of 300 to 600 g/mol;

v) tetraethylene glycol diacrylates;

vi) acrylates of propoxylated tetrahydro-2-furanmethanols containing 1 to 3 oxypropylene units per molecule;

vii) diacrylates of linear polybutadiene polymers, where the polymers are linear polybutadiene polymers with hydroxyl end groups;

viii) diacrylates of bisphenol A and ethoxylated bisphenol A containing 1 to 35 oxyethylene units per molecule;

ix) diacrylates of ethoxylated 1,6-hexanediols containing 1 to 6 oxyethylene units per molecule;

x) diacrylates of propoxylated 1,6-hexanediols containing 1 to 4 oxypropylene units per molecule;

xi) diacrylates of ethoxylated neopentyl glycols containing 1 to 3 oxyethylene units per molecule;

xii) acrylate-terminated oligomers obtainable by reaction of caprolactone acrylate with a polyisocyanate selected from the group consisting of dicyclohexylmethane diisocyanate, toluene diisocyanate, and hexamethylene diisocyanate biuret;

xiii) acrylate-terminated oligomers obtainable by reaction of 2-hydroxyethyl acrylate, isophorone diisocyanate and neopentyl glycol-co-adipic acid polyester polyol, the polyester polyol having a number average molecular weight of 400 to 2500 g/mol;

xiv) acrylate-terminated oligomers obtainable by reaction of 2-hydroxyethyl acrylate, a diisocyanate selected from toluene diisocyanate or isophorone diisocyanate, and polypropylene glycol, wherein the polypropylene glycol is a diol or triol and has a number average molecular weight of 800 to 5000 g/mol;

xv) acrylate-terminated oligomers obtainable by reaction of 2-hydroxyethyl acrylate, a diisocyanate selected from isophorone diisocyanate or dicyclohexylmethane diisocyanate, and polytetramethylene ether glycol, wherein the polytetramethylene glycol has a number average molecular weight of 500 to 1200 g/mol;

xvi) acrylate-terminated oligomers obtainable by reaction of 2-hydroxyethyl acrylate, toluene diisocyanate, and ethylene glycol-co-propylene glycol-co-adipic acid polyester polyol, wherein the polyester polyol has a number average molecular weight of 2500 to 3500 g/mol;

xvii) acrylate-terminated oligomers obtainable by reaction of 2-hydroxyethyl acrylate, a polyisocyanate selected from toluene diisocyanate or dicyclohexylmethane diisocyanate, and ethylene glycol-co-adipic acid polyester polyol, wherein the polyester polyol has a number average molecular weight of 500 to 1000 g/mol;

xviii) acrylate-terminated oligomers obtainable by reaction of 2-hydroxyethyl acrylate, isophorone diisocyanate, and hydroxyl-terminated polysiloxane/polyethylene oxide block copolymer, wherein the hydroxyl-terminated polysiloxane/polyethylene oxide block copolymer has a number average molecular weight of 1500 to 3000 g/mol;

xix) acrylate-terminated oligomers obtainable by reaction of acrylic acid and glycidyl ethers of bisphenol A;

xx) acrylate-terminated oligomers obtainable by reaction of acrylic acid, glycidyl ethers of bisphenol A, diethylene glycol, and phthalic anhydride;

xxi) acrylate-terminated oligomers obtainable by reaction of acrylic acid and glycidyl neodecanoate;

xxii) acrylate-terminated oligomers obtainable by reaction of 2-hydroxyethyl acrylate and hexamethylene diisocyanate biuret;

xxiii) acrylate-terminated oligomers obtainable by reaction of acrylic acid and unsaturated fatty acid dimer diol; and

xxiv) acrylate-terminated oligomers obtainable by reaction of acrylic acid, toluene diisocyanate, and bisphenol A;

b) 0 to 5% by weight in total, based on the weight of the curable composition, of (meth) acrylate-functionalized compounds comprising three or more (meth) acrylate functional groups per molecule;

c) optionally, at least one comonomer having structure R a R b C=CHR c , wherein R a and R b are the same as or different from each other and are selected from —C(═O) XR d , —CH 2 C(═O)XR e , and —C(═O)R f , subject to the proviso that R a and R b are not both —CH 2 C(═O)XR e ; wherein each X is independently O or NR i , with each R i being independently selected from H or an organic group, wherein each R d and R e is independently selected from H, alkali metal, or an organic group; and wherein each R f is an organic group; or wherein two of R d , R e or R f are taken together with the atoms to which they are bound to form a ring;

d) optionally, at least one tackifier;

e) optionally, at least one initiator system;

f) optionally, at least one additive which is not a tackifier or part of an initiator system;

wherein:

the curable composition has a ratio of moles of methacrylate functional groups to moles of acrylate functional groups of 0:1 to 1:1; and

the curable composition, when cured, provides a pressure sensitive adhesive which passes an in vitro cytotoxicity test as measured in accordance with ISO 10993-5 (2009),

wherein acrylate-functionalized compounds i)-xxiv) comprise at least 80% by weight of the total weight of (meth)acrylate-functionalized compounds present in the curable composition.

2 . The curable composition of claim 1 , wherein the curable composition has a ratio of moles of methacrylate functional groups to moles of acrylate functional groups of 0:1 to 0.5:1; 0:1 to 0.2:1; 0:1 to 0.1:1; or 0:1 to 0.05:1.

3 . The curable composition of claim 1 , wherein the curable composition, when cured, has a glass transition temperature of not more than 20° C.

4 . The curable composition of claim 1 , wherein the curable composition comprises at least one initiator system and wherein the at least one initiator system comprises at least one photoinitiator.

5 . The curable composition of claim 1 , further comprising methacrylate-functionalized compounds in an amount up to 1% by weight in total, based on the weight of the curable composition.

6 . The curable composition of claim 1 , comprising acrylate-functionalized compounds comprising three or more acrylate functional groups per molecule in an amount up to 4% by weight in total, based on the weight of the curable composition.

7 . The curable composition of claim 1 , comprising the at least one tackifier in an amount up to 35% by weight, based on the weight of the curable composition.

8 . The curable composition of claim 7 , wherein the one or more tackifiers are selected from the group consisting of hydrogenated and non-hydrogenated piperylene-based hydrocarbon resins, hydrogenated and non-hydrogenated rosin esters, and maleic anhydride-modified rosin esters.

9 . The curable composition of claim 1 , wherein the curable composition additionally comprises one or more additives selected from the group consisting of wetting agents, matting agents, colorants, dyes, pigments, adhesion promoters, fillers, rheology modifiers, thixotropic agents, plasticizers, UV absorbers, UV stabilizing agents, dispersants, antioxidants, antistatic agents, lubricants, opacifying agents, anti-foam agents, and rheology agents.

10 . The curable composition of claim 1 , wherein the curable composition comprises at least one of acrylate-functionalized compounds xiii)-xviii), at least one high Tg monofunctional monomer, and at least one low Tg monofunctional monomer.

11 . The curable composition of claim 10 , wherein the at least one high Tg monofunctional monomer includes at least one comonomer having structure R a R b C═CHR c , wherein R a and R b are the same as or different from each other and are selected from —C(═O)XR d , —CH 2 C(═O)XR e , and —C(═O)R f , subject to the proviso that R a and R b are not both —CH 2 C(═O)XR e ; wherein each X is independently O or NR i , with each R i being independently selected from H or an organic group, wherein each R d and R e is independently selected from H, alkali metal, or an organic group; and wherein each R f is an organic group; or wherein two of R d , R e or R f are taken together with the atoms to which they are bound to form a ring.

12 . The curable composition of claim 10 , wherein the at least one low Tg monofunctional monomer includes at least one of acrylate-functionalized compounds i), ii), iii), iv) or vi).

13 . The curable composition of claim 10 , wherein the at least one high Tg monofunctional monomer and the at least one low Tg monofunctional monomer are present in a mass ratio of from 1:5 to 5:1.

14 . The curable composition of claim 1 , wherein the curable composition comprises at least one of acrylate-functionalized compounds i)-xi) and at least one of acrylate-functionalized compounds xiii)-xviii).

15 . The curable composition of claim 1 , wherein the curable composition comprises at least one acrylate-functionalized compound iii) and at least one acrylate-functionalized compound xiii).

16 . The curable composition of claim 1 , wherein the curable composition comprises at least one acrylate-functionalized compound iii), at least one acrylate-functionalized compound xiii), and at least one comonomer c) selected from the group consisting of dicyclohexyl methylene malonate, di-isobornyl methylene malonate, ethyl isobornyl methylene malonate, dihexyl methylene malonate and diethyl methylene malonate.

17 . A method of making a pressure sensitive adhesive, comprising curing a curable composition in accordance with claim 1 .

18 . The method of claim 17 , wherein curing comprises exposing the curable composition to at least one of ultraviolet light, visible light and electron beam radiation.

19 . A film, wherein the film is a pressure sensitive adhesive formed by curing the curable composition of claim 1 .

20 . An article, wherein the article comprises a film in accordance with claim 19 disposed on at least one surface of a substrate.

21 . The article of claim 20 , wherein the substrate is a flexible polymeric substrate.

22 . The article of claim 20 , wherein the substrate passes an in vitro cytotoxicity test as measured in accordance with ISO 10993-5 (2009).