Acrylate-terminated urethane polybutadienes from low-monomer 1:1 monoadducts from reactive olefinic compounds and diisocyanates and hydroxy-terminated polybutadienes for liquid optically clear adhesives (LOCAs)

Patent metadata

Field	Value
Publication number	US-10385240-B2
Application number	US-201615375225-A
Country	US
Kind code	B2
Filing date	Dec 12, 2016
Priority date	Dec 21, 2015
Publication date	Aug 20, 2019
Grant date	Aug 20, 2019

Abstract

The present invention relates to an optical clear resin and a method for producing a liquid optical clear photo-curable adhesive.

First claim

The invention claimed is:

1. A method to make a liquid optically clear adhesive comprising from 20 to 80 wt.-% of acrylate-terminated urethane polybutadienes 1) in formulations in combination with at least one liquid component selected from 30 to 70 wt.-% plasticizer and/or from 5 to 30 wt.-% reactive (meth)acrylates 2), wherein
the acrylate-terminated urethane polybutadienes 1) is made by the method comprising the steps of
A) at least one low-monomer 1:1 monoadduct with a free diisocyanate content below 2.0 wt. %
from
a1) at least one aliphatic, cycloaliphatic, and/or araliphatic diisocyanate
and
a2) at least one reactive olefinic compound having at least one methacrylate group and/or acrylate group and/or vinyl ether group and exactly one OH group

B) with at least one hydroxy-terminated polybutadiene and/or one at least partially or completely hydrogenated hydroxyterminated polybutadiene, and
C) with of at least one polymerization inhibitor

wherein the at least one low-monomer 1:1 monoadduct with a free diisocyanate content below 2.0 wt. % comprises a NCO group wherein the liquid optically clear adhesive is substantially transparent for optical applications wherein the liquid optically clear adhesive has at least 90% transmittance when air is used as a blank measured following the DIN 5033.

2. The method according to claim 1 , wherein the ratio of the NCO groups of component A) to the OH groups of component B) ranges from 1.2:1 and 1:40 wherein the liquid optically clear adhesive is substantially transparent for optical applications wherein, after 150° C. for 60 minute, the liquid optically clear adhesive has at least 90% transmission over the range of from 380 to 780 nm and a haze % of from 0.40 to 0.65.

3. The method according to claim 1 , wherein the low-content-monomer 1:1 monoadducts A) are prepared, from, as starting compounds,
a1) at least one aliphatic, cycloaliphatic and/or araliphatic diisocyanate in an amount of 1-20 mol, and
a2) 1 mol of at least one reactive olefinic compound having at least one methacrylate group and/or acrylate group and/or vinyl ether group and exactly one OH group, obtained by reaction in a temperature range of 40-120° C., the unreacted diisocyanate being separated off subsequently by a short-path distillation at 80-220° C./0.01-10 mbar from the reaction product,
wherein the short-path distillation takes place in the presence of
a3) at least one inhibitor which possesses at least one functional group reactive toward NCO groups
wherein the liquid optically clear adhesive is substantially transparent for optical applications wherein, after 200° C. for 60 minute, the liquid optically clear adhesive has at least 90% transmittance when air is used as a blank measured following the DIN 5033 and a haze % of from 0.40 to 0.80, and a viscosity at 25° C. of from 2450 cP to 10,800 cP.

4. A liquid optically clear adhesive comprising
1) from 20 to 80 wt.-% of acrylate terminated urethane polybutadienes, wherein the acrylate terminated urethane polybutadienes are obtained by the reaction of
A) a low-monomer-content 1:1 monoadduct, having a free diisocyanate content of less than 2 wt. %, the monoadduct being based on at least one aliphatic, cycloaliphatic and/or araliphatic diisocyanate a1) and at least one reactive olefinic compound having at least one methacrylate group and/or acrylate group and/or vinyl ether group and exactly one OH group a2), and
B) at least one hydroxyterminated polybutadiene and/or one at least partially or completely hydrogenated hydroxyterminated polybutadiene,
C) in the presence of at least one polymerization inhibitor and

2) a liquid component selected from 30 to 70 wt.-% plasticizer and/or from 5 to 30 wt.-% reactive (meth)acrylates, and
3) from 0.5 to 5 wt.-% of a photo-polymerization initiators
wherein the liquid optically clear adhesive is substantially transparent for optical applications wherein the liquid optically clear adhesive has at least 90% transmittance when air is used as a blank measured following the DIN 5033.

5. The liquid optically clear adhesive according to claim 4 , wherein the plasticizer is selected from the group consisting of polyisoprene resin, polybutadiene resin, hydrogenated polybutadiene, xylene polymer, hydroxyl-terminated polybutadiene and/or hydroxyl-terminated polyolefin, terpene polymer resin, phthalates, trimellitates, adipates, benzoate ester, hexanoate and dicarboxylate.

6. The liquid optically clear adhesive according to claim 4 , wherein the reactive (meth)acrylate is selected from the group consisting of methyl (meth)acrylate, ethyl (meth)acrylate, n- or iso-propyl (meth)acrylate, n- or iso- or tert-butyl (meth)acrylate, 2-(2-ethoxyethoxy) ethyl acrylate, tetrahydrofurfury (meth)acrylate, lauryl acrylate, isooctyl acrylate, isodecyl acrylate, 2-phenoxyethyl acrylate, 2-ethylhexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentadienyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, caprolactone acrylate, morpholine (meth)acrylate, hexanediol di(meth)acrylate, ethyleneglycol dimethacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate and combinations thereof.

7. The liquid optically clear adhesive according to claim 4 , wherein the photo-polymerization initiator is selected from the group consisting of 1-Hydroxy-cyclohexyl-phenyl-ketone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenyl phosphinate, Bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide, 2-Benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-Dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl) butan-1-one, 1-[4-(Phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyloxime), and 1-[9-Ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-ethanone-1-(O-acetyloxime).

8. The liquid optically clear adhesive according to claim 4 , comprising
1) from 30 to 70 wt.-% of acrylate terminated urethane polybutadienes, wherein the acrylate terminated urethane polybutadienes are obtained by reaction of
A) at least one low-monomer-content 1:1 monoadduct, having a free diisocyanate content of less than 2% by weight, the monoadduct being based on at least one aliphatic, cycloaliphatic and/or araliphatic diisocyanate a 1) and at least one reactive olefinic compound having at least one methacrylate group and/or acrylate group and/or vinyl ether group and exactly one OH group a2), and
B) at least one hydroxyterminated polybutadiene
C) optionally in the presence of at least one polymerization inhibitor and

2) a liquid component selected from 30 to 70 wt.-% of at least one plasticizer and/or from 10 to 25 wt.-% of reactive (meth)acrylates, and
3) from 2 to 5 wt.-% of photo-polymerization initiators
wherein the liquid optically clear adhesive is substantially transparent for optical applications wherein, after 150° C. for 60 minute, the liquid optically clear adhesive has at least 90% transmittance when air is used as a blank measured following the DIN 5033 and a haze % of from 0.40, to 0.65, and a viscosity at 25° C. of from 2450 cP to 10,800 cP.

9. A process for binding a top substrate to a base substrate, in which
(a) the formulations according to claim 4 , is applied onto the top side of the base substrate,
(b) the top substrate is attached on the adhesive layer of step (a),
(c) the adhesive is hardened by exposure to electromagnetic radiation comprising a wavelength ranging from 200 nm to 700 nm.

10. The process according to claim 9 , wherein the base substrate is a display panel, selected from a liquid crystal display, a plasma display, a light-emitting diode (LED) display, an electrophoretic displa

Assignees

• Evonik Degussa Gmbh

Inventors

• Ramon-Gimenez Laura
• Haberkorn Niko
• Krannig Kai-Steffen
• Kolb Nicolai
• Wu Hsin-Ho
• Steiger Juergen
• Sun Tung-Yi

Classifications

• C08F290/067 Primary

  Polyurethanes; Polyureas · CPC title

• C09J175/16

  having terminal carbon-to-carbon unsaturated bonds · CPC title

• C09D175/16

  having terminal carbon-to-carbon unsaturated bonds · CPC title

• C08G2190/00

  Compositions for sealing or packing joints · CPC title

• C08G18/755

  and at least one isocyanate or isothiocyanate group linked to a secondary carbon atom of the cycloaliphatic ring, e.g. isophorone diisocyanate · CPC title