U.S. patent application number 13/201812 was filed with the patent office on 2011-12-08 for modified polyvinyl alcohol resins and adhesive, polarizer, and display device containing the same.
Invention is credited to Ki-Ok Kwon, Seong-Jun Park, Kyun-Il Rah.
Application Number | 20110300387 13/201812 |
Document ID | / |
Family ID | 42634355 |
Filed Date | 2011-12-08 |
United States Patent
Application |
20110300387 |
Kind Code |
A1 |
Park; Seong-Jun ; et
al. |
December 8, 2011 |
MODIFIED POLYVINYL ALCOHOL RESINS AND ADHESIVE, POLARIZER, AND
DISPLAY DEVICE CONTAINING THE SAME
Abstract
Provided are a modified polyvinyl alcohol-based resin with an
acrylic group introduced thereto and including a hydroxyl group
formed during the introduction of the acrylic group, an adhesive
including the modified polyvinyl alcohol-based resin having
excellent adhesion, humidity resistance, and water resistance, an
adhesive including a polyvinyl alcohol-based resin, and a compound
having an epoxy group, and an acrylic group, a polarizing plate and
an image display device including the adhesive. The adhesive for a
polarizing plate according to an embodiment of the present
invention has excellent adhesion, humidity resistance, and water
resistance as well as having excellent solubility with respect to
water and an increase in adhesion while physical properties of a
typical polyvinyl alcohol-based resin are maintained.
Inventors: |
Park; Seong-Jun; (Daejeon,
KR) ; Kwon; Ki-Ok; (Daejeon, KR) ; Rah;
Kyun-Il; (Daejeon, KR) |
Family ID: |
42634355 |
Appl. No.: |
13/201812 |
Filed: |
February 22, 2010 |
PCT Filed: |
February 22, 2010 |
PCT NO: |
PCT/KR2010/001091 |
371 Date: |
August 16, 2011 |
Current U.S.
Class: |
428/414 ;
428/522; 525/61 |
Current CPC
Class: |
G02B 5/3033 20130101;
C09J 129/04 20130101; Y10T 428/31935 20150401; G02B 1/14 20150115;
C09J 151/003 20130101; Y10T 428/31515 20150401; G02B 5/305
20130101 |
Class at
Publication: |
428/414 ; 525/61;
428/522 |
International
Class: |
C09J 129/04 20060101
C09J129/04; G02B 5/30 20060101 G02B005/30; B32B 27/30 20060101
B32B027/30; B32B 7/12 20060101 B32B007/12; C08F 8/00 20060101
C08F008/00; C08F 8/08 20060101 C08F008/08 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 20, 2009 |
KR |
10-2009-0014468 |
Claims
1. A modified polyvinyl alcohol-based resin with an acrylic group
introduced thereto and comprising a hydroxyl group formed during
the introduction of the acrylic group.
2. The modified polyvinyl alcohol-based resin of claim 1, wherein
the acrylic group is introduced in a range of about 0.1 mol % to
about 50 mol %.
3. The modified polyvinyl alcohol-based resin of claim 1, wherein
the modified polyvinyl alcohol-based resin is obtained by
performing a reaction between a polyvinyl alcohol-based resin and a
compound having epoxy and acrylic groups.
4. The modified polyvinyl alcohol-based resin of claim 1, wherein
the modified polyvinyl alcohol-based resin comprises a repeating
unit of the following Chemical Formula A and at least one repeating
unit of the following Chemical Formulas B1, B2, and B3.
##STR00010## (where n is an integer between about 490 and about
1700, m is an integer between about 10 and about 900, n+m is an
integer between about 500 and about 1800, R.sup.1 is substituted or
unsubstituted C.sub.1-C.sub.20 alkandiyl, a substituted or
unsubstituted 1- to 7-membered cyclic group, a substituted or
unsubstituted 1- to 7-membered heterocyclic group including a
heteroatom selected from the group consisting of N, S, or O, a
substituted or unsubstituted C.sub.6-C.sub.14 aromatic group, or a
substituted or unsubstituted 1- to 7-membered heteroaromatic group
including at least one heteroatom selected from the group
consisting of N, S, or O, R.sup.2 is a substituted or unsubstituted
C.sub.1-C.sub.20 alkyl group, a substituted or unsubstituted 1- to
7-membered cyclic group, a substituted or unsubstituted 1- to
7-membered heterocyclic group including at least one heteroatom
selected from the group consisting of N, S, or O, a substituted or
unsubstituted C.sub.6-C.sub.14 aromatic group, or a substituted or
unsubstituted 1- to 7-membered heteroaromatic group including at
least one heteroatom selected from the group consisting of N, S, or
O, and when R.sup.1 and R.sup.2 are substituted with a substituent,
the substituent is a C.sub.1-C.sub.20 alkyl group, a halogen atom
selected from the group consisting of F, Cl, Br, or I, a 1- to
7-membered cyclic group, a 1- to 7-membered heterocyclic group
including at least one heteroatom selected from the group
consisting of N, S, or O, a C.sub.6-C.sub.14 aromatic group, or a
1- to 7-membered heteroaromatic group including at least one
heteroatom selected from the group consisting of N, S, or O)
5. The modified polyvinyl alcohol-based resin of claim 4, wherein
the modified polyvinyl alcohol-based resin further comprises a
repeating unit of the following Chemical Formula C, a sum of the
number (n) of the repeating unit of Chemical Formula A and the
number (l) of the repeating unit of Chemical Formula C is an
integer between about 490 and about 1700, the number (l) of the
repeating unit of Chemical Formula C in the sum of n and l is an
integer between about 1 and about 80, the number (m) of the one
repeating unit of Chemical Formulas B1, B2, and B3 is an integer
between about 10 and about 900, and a sum of n, m, and l is an
integer between about 500 and about 1800. ##STR00011## (where 1 is
an integer between about 1 and 80, and R.sup.3 is an acetoacetyl
group, a carboxylic acid group, an acrylic group, or a urethane
group)
6. The modified polyvinyl alcohol-based resin of claim 3, wherein
an average degree of polymerization of the polyvinyl alcohol-based
resin is in a range of about 500 and about 1800.
7. The modified polyvinyl alcohol-based resin of claim 3, wherein
the compound having epoxy and acrylic groups is represented as the
following Chemical Formula 1 or Chemical Formula 2. ##STR00012##
(where R.sup.1 is substituted or unsubstituted C.sub.1-C.sub.20
alkandiyl, a substituted or unsubstituted 1- to 7-membered cyclic
group, a substituted or unsubstituted 1- to 7-membered heterocyclic
group including a heteroatom selected from the group consisting of
N, S, or O, a substituted or unsubstituted C.sub.6-C.sub.14
aromatic group, or a substituted or unsubstituted 1- to 7-membered
heteroaromatic group including at least one heteroatom selected
from the group consisting of N, S, or O, R.sup.2 is a substituted
or unsubstituted C.sub.1-C.sub.20 alkyl group, a substituted or
unsubstituted 1- to 7-membered cyclic group, a substituted or
unsubstituted 1- to 7-membered heterocyclic group including at
least one heteroatom selected from the group consisting of N, S, or
O, a substituted or unsubstituted C.sub.6-C.sub.14 aromatic group,
or a substituted or unsubstituted 1- to 7-membered heteroaromatic
group including at least one heteroatom selected from the group
consisting of N, S, or O, and when R.sup.1 and R.sup.2 are
substituted with a substituent, the substituent is a
C.sub.1-C.sub.20 alkyl group, a halogen atom selected from the
group consisting of F, Cl, Br, or I, a 1- to 7-membered cyclic
group, a 1- to 7-membered heterocyclic group including at least one
heteroatom selected from the group consisting of N, S, or O, a
C.sub.6-C.sub.14 aromatic group, or a 1- to 7-membered
heteroaromatic group including at least one heteroatom selected
from the group consisting of N, S, or O)
8. An adhesive for a polarizing plate comprising the modified
polyvinyl alcohol-based resin of claim 1.
9. An adhesive for a polarizing plate comprising about 100 parts by
weight of the polyvinyl alcohol-based resin and about 0.001 to 10
parts by weight of the compound having epoxy and acrylic
groups.
10. The adhesive for a polarizing plate of claim 9, wherein an
average degree of polymerization of the polyvinyl alcohol-based
resin is in a range of about 500 and about 1800.
11. The adhesive for a polarizing plate of claim 9, wherein the
compound having epoxy and acrylic groups is represented as the
following Chemical Formula 1 or Chemical Formula 2. ##STR00013##
(where R.sup.1 is substituted or unsubstituted C.sub.1-C.sub.20
alkandiyl, a substituted or unsubstituted 1- to 7-membered cyclic
group, a substituted or unsubstituted 1- to 7-membered heterocyclic
group including a heteroatom selected from the group consisting of
N, S, or O, a substituted or unsubstituted C.sub.6-C.sub.14
aromatic group, or a substituted or unsubstituted 1- to 7-membered
heteroaromatic group including at least one heteroatom selected
from the group consisting of N, S, or O, R.sup.2 is a substituted
or unsubstituted C.sub.1-C.sub.20 alkyl group, a substituted or
unsubstituted 1 to 7-membered cyclic group, a substituted or
unsubstituted 1- to 7-membered heterocyclic group including at
least one heteroatom selected from the group consisting of N, S, or
O, a substituted or unsubstituted C.sub.6-C.sub.14 aromatic group,
or a substituted or unsubstituted 1- to 7-membered heteroaromatic
group including at least one heteroatom selected from the group
consisting of N, S, or O, and when R.sup.1 and R.sup.2 are
substituted with a substituent, the substituent is a
C.sub.1-C.sub.20 alkyl group, a halogen atom selected from the
group consisting of F, Cl, Br, or I, a 1- to 7-membered cyclic
group, a 1- to 7-membered heterocyclic group including at least one
heteroatom selected from the group consisting of N, S, or O, a
C.sub.6-C.sub.14 aromatic group, or a 1- to 7-membered
heteroaromatic group including at least one heteroatom selected
from the group consisting of N, S, or O)
12. The adhesive for a polarizing plate of claim 8, wherein the
adhesive for a polarizing plate further comprises an initiator
selected from the group consisting of
2,2'-azo-bis(isobutyronitrile) (AIBN)-based and persulfate-based
water-soluble initiators.
13. The adhesive for a polarizing plate of claim 12, wherein the
initiator is added to a maximum of about 10 wt %.
14. A polarizing plate comprising a polarizer and a protective film
adhered to each other with the adhesive for a polarizing plate of
claim 8.
15. A display device comprising the polarizing plate of claim
14.
16. The adhesive for a polarizing plate of claim 9, wherein the
adhesive for a polarizing plate further comprises an initiator
selected from the group consisting of
2,2'-azo-bis(isobutyronitrile) (AIBN)-based and persulfate-based
water-soluble initiators.
17. The adhesive for a polarizing plate of claim 16, wherein the
initiator is added to a maximum of about 10 wt %.
18. A polarizing plate comprising a polarizer and a protective film
adhered to each other with the adhesive for a polarizing plate of
claim 9.
19. A display device comprising the polarizing plate of claim 18.
Description
TECHNICAL FIELD
[0001] The present invention relates to a polyvinyl alcohol-based
resin having improved adhesion, humidity resistance, and water
resistance, an adhesive including the same, a polarizing plate, and
a display device, and more particularly, to a modified polyvinyl
alcohol-based resin with an acrylic group introduced thereto and
having a hydroxyl group formed by the introduction of the acrylic
group; an adhesive for a polarizing plate including the modified
polyvinyl alcohol-based resin having excellent adhesion, humidity
resistance, and water resistance; an adhesive for a polarizing
plate including a polyvinyl alcohol-based resin and a compound
having an epoxy group and an acrylic group; a polarizing plate and
a display device including the adhesive for a polarizing plate.
BACKGROUND ART
[0002] A polarizing plate, used in various image display devices
such as a liquid crystal display (LCD) device, a plasma display
panel (PDP), and an electroluminescent (EL) device, has a structure
including a polarizer formed of a polyvinyl alcohol-based film and
a transparent protective film formed on at least one surface of the
polarizer. At this time, a water-based adhesive is used as an
adhesive for a polarizing plate that is applied to a polarizing
plate to bond the polarizer and the transparent protective film,
and in particular, a polyvinyl alcohol-based adhesive is used, in
which a cross-linking agent is mixed with a polyvinyl alcohol-based
resin aqueous solution.
[0003] When a typical polyvinyl alcohol-based resin adhesive is
used, the polarizer and transparent protective film adhere to each
other by means of hydrogen bonds of the polyvinyl alcohol-based
resin adhesive. However, a typical polyvinyl alcohol-based resin
adhesive has limitations in terms of reductions of initial
adhesion, humidity resistance, and water resistance. In order to
improve such limitations, an adhesive for a polarizing plate
including a cross-linking agent and a polyvinyl alcohol-based resin
containing an acetacetyl group was disclosed in Japanese Patent
Laid-Open Publication No. 1995-198945. Also, an adhesive
composition for a polarizing plate including polyvinyl alcohol, a
copolymer resin (having a degree of copolymerization ranging
between 1900 and 2500) of a hydrophobic vinyl monomer such as ethyl
acrylate, methyl acrylate, acrylic acid, and methacrylic acid, and
a metal hardener was disclosed in Korean Patent Laid-Open
Publication No. 2006-88245.
[0004] Korean Patent Laid-Open Publication No. 2006-133215
disclosed a polyvinyl alcohol-based adhesive composition including
15 to 75 percent by weight of a water-soluble acrylate-based
cross-linking agent of polyvinyl alcohol. However, there are
limitations in the reduction of solubility of the adhesive with
respect to water, and the reduction of adhesiveness due to the
addition of a large amount of a water-insoluble acrylate
cross-linking agent is combined in the adhesive composition of
Korean Patent Laid-Open Publication No. 2006-133215.
[0005] However, as line speed (elongation rate) has recently
increased in order to improve the productivity of the polarizing
plate, there are also limitations in that the humidity resistance,
water resistance, and adhesion of the adhesive for a polarizing
plate using the polyvinyl alcohol-based resin containing a typical
acetacetyl group may be insufficient.
[0006] Therefore, an adhesive for bonding a polarizer and a
protective film having improved solubility with respect to water,
excellent adhesiveness with respect to the polarizer and the
protective film, humidity resistance, and water resistance is
required.
DISCLOSURE
Technical Problem
[0007] An aspect of the present invention provides a modified
polyvinyl alcohol-based resin with an acrylic group introduced
thereto and including a hydroxyl group formed by the introduction
of the acrylic group.
[0008] Another aspect of the present invention provides an adhesive
having excellent adhesiveness, humidity resistance, water
resistance, and solubility with respect to water.
[0009] Another aspect of the present invention provides an adhesive
for bonding a polarizer and a protective film (hereinafter,
referred to as the `adhesive for a polarizing plate`).
[0010] Another aspect of the present invention provides an
excellent water and humidity resistant polarizing plate including
the adhesive for a polarizing plate and a display device including
the polarizing plate.
Technical Solution
[0011] According to an aspect of the present invention, there is
provided a modified polyvinyl alcohol-based resin with an acrylic
group introduced thereto and including a hydroxyl group formed by
the introduction of the acrylic group.
[0012] According to another aspect of the present invention, there
is provided an adhesive for a polarizing plate including the
modified polyvinyl alcohol-based resin with an acrylic group
introduced thereto and including a hydroxyl group formed by the
introduction of the acrylic group.
[0013] According to another aspect of the present invention, there
is provided an adhesive for a polarizing plate including 100 parts
by weight of the polyvinyl alcohol-based resin and 0.001 to 10
parts by weight of the compound having epoxy and acrylic
groups.
[0014] According to another aspect of the present invention, there
is provided a polarizing plate including a polarizer and a
protective film adhered to each other with the adhesive for a
polarizing plate according to an embodiment of the present
invention.
[0015] According to another aspect of the present invention, there
is provided a display device including the polarizing plate
according to an embodiment of the present invention.
Advantageous Effects
[0016] An adhesive for a polarizing plate including a modified
polyvinyl alcohol-based resin with an acrylic group introduced
thereto and having a hydroxyl group formed by the introduction of
the acrylic group or an adhesive for a polarizing plate including a
polyvinyl alcohol-based resin and a compound having an epoxy group
and an acrylic group according to an embodiment of the present
invention has excellent adhesion, humidity resistance, and water
resistance as well as having excellent solubility with respect to
water.
[0017] That is, an acrylic resin is an organic solvent-soluble
resin which is not appropriate for using as an adhesive for a
polarizing plate because of low solubility with respect to water.
Also, a resin, in which a hydrophobic monomer such as (meth)acrylic
acid or (meth)acrylate is copolymerized with a typical polyvinyl
alcohol-based resin, is impossible to use as a water-based adhesive
for a polarizing plate because of the low solubility thereof with
respect to water. However, the adhesive for a polarizing plate
according to the present invention has excellent adhesiveness,
water resistance, and humidity resistance as well as having
excellent solubility with respect to water because adhesion, water
resistance, humidity resistance and solubility with respect to
water by means of a hydroxyl group are complementarily optimized.
Therefore, water resistance and humidity resistance of polarizing
plate fabricated using the adhesive of the present invention and a
display device including the polarizing plate are improved.
BEST MODE
[0018] Exemplary embodiments of the present invention will now be
described in detail.
[0019] A modified polyvinyl alcohol-based resin (hereinafter,
referred to as the `AH-PVA`) has an acrylic group introduced
thereto and includes a hydroxyl group formed by the introduction of
the acrylic group. The modified polyvinyl alcohol-based resin with
an acrylic group introduced thereto and having a hydroxyl group
formed by the introduction of the acrylic group includes a
repeating unit of the following Chemical Formula A, and at least
one repeating unit of the following Chemical Formula B1, B2, and
B3. For example, the modified polyvinyl alcohol-based resin with an
acrylic group introduced thereto and having a hydroxyl group formed
by the introduction of the acrylic group may further include a
repeating unit of the following Chemical Formula C.
##STR00001##
[0020] An AHA-PVA resin including repeating units of Chemical
Formulas A, B1, and C according to the present invention may be
represented as Chemical Formula I below. However, the AHA-PVA resin
is not limited thereto.
##STR00002##
[0021] An AHA-PVA resin including repeating units of Chemical
Formulas A, B2, and C may be represented as Chemical Formula II
below.
##STR00003##
[0022] An AHA-PVA resin including repeating units of Chemical
Formulas A, B3, and C may be expressed as Chemical Formula III
below.
##STR00004##
[0023] When the AHA-PVA resin includes a repeating unit of Chemical
Formula A and at least one repeating unit of Chemical Formulas B1,
B2, and B3, the number (n) of the repeating unit of Chemical
Formula A in the AH-PVA resin is an integer between 490 to 1700,
and the number (m) of the repeating unit represented as Chemical
Formula B1, B2, and/or B3 is an integer between 10 and 900, for
example, 10 and 400. The number (m) may be an integer between 50
and 180, and the sum of n and m is an integer between 500 and
1800.
[0024] Further, according to an embodiment of the present
invention, when the AH-PVA resin includes a repeating unit of
Chemical Formula A, at least one repeating unit of Chemical
Formulas B1, B2, and B3, and a repeating unit of Chemical Formula
C, the sum of the number (n) of the repeating unit of Chemical
Formula A and the number (l) of the repeating unit of Chemical
Formula C in the AH-PVA resin is an integer between 490 and 1700.
The number (l) of the repeating unit of Chemical Formula C in the
sum of n and l is an integer between 1 and 80. The number (m) of at
least one repeating unit of Chemical Formulas B1, B2, and B3 is an
integer between 10 and 900, for example between 10 and 400. The
number (m) may be an integer between 50 and 180, and the sum of n,
m, and l may be an integer between 500 and 1800. When the AH-PVA
resin includes the repeating units of Chemical Formula A, Chemical
Formulas B1, B2, and/or B3, and Chemical Formula C, a modified
polyvinyl alcohol-based resin is used as a PVA resin in which a
portion of the PVA resin is at least one group selected from the
group consisting of an acetoacetyl group, a carboxylic acid group,
an acrylic group, or a urethane group. R.sup.1 is substituted or
unsubstituted C.sub.1-C.sub.20 alkandiyl, preferably,
C.sub.1-C.sub.15 alkandiyl, more preferably, C.sub.1-C.sub.10
alkandiyl, further preferably, C.sub.1-C.sub.5 alkandiyl, a
substituted or unsubstituted 1- to 7-membered cyclic group, a
substituted or unsubstituted 1- to 7-membered heterocyclic group
including a heteroatom selected from the group consisting of N, S,
or O, a substituted or unsubstituted C.sub.6-C.sub.14 aromatic
group, or a substituted or unsubstituted 1- to 7-membered
heteroaromatic group including at least one heteroatom selected
from the group consisting of N, S, or O. R.sup.2 is a substituted
or unsubstituted C.sub.1-C.sub.20 alkyl group, preferably, a
C.sub.1-C.sub.15 alkyl group, more preferably, C.sub.1-C.sub.10
alkyl group, further preferably, a C.sub.1-C.sub.5 alkyl group, a
substituted or unsubstituted 1- to 7-membered cyclic group, a
substituted or unsubstituted 1- to 7-membered heterocyclic group
including at least one heteroatom selected from the group
consisting of N, S, or O, a substituted or unsubstituted
C.sub.6-C.sub.14 aromatic group, or a substituted or unsubstituted
1- to 7-membered heteroaromatic group including a heteroatom
selected from the group consisting of N, S, or O. When R.sup.1 and
R.sup.2 are substituted with a substituent, the substituent is a
C.sub.1-C.sub.20 alkyl group, preferably, a C.sub.1-C.sub.15 alkyl
group, more preferably, a C.sub.1-C.sub.10 alkyl group, for
example, a C.sub.1-C.sub.5 alkyl group, a halogen atom selected
from the group consisting of F, Cl, Br, or I, a 1- to 7-membered
cyclic group, a 1- to 7-membered heterocyclic group including at
least one heteroatom selected from the group consisting of N, S, or
O, a C.sub.6-C.sub.14 aromatic group, or a 1- to 7-membered
heteroaromatic group including at least one heteroatom selected
from the group consisting of N, S, or O. R.sup.3 may be an
acetoacetyl group, a carboxylic acid group, an acrylic group, or a
urethane group.
[0025] In Chemical Formulas I to III, although polymers are
represented in which the repeating units of Chemical Formula A,
Chemical Formulas B1, B2, and/or B3, and optional Chemical Formula
C are sequentially connected for the sake of convenience, Chemical
Formula A, Chemical Formulas B1, B2, and/or B3, and optional
Chemical Formula C may be randomly positioned in the polymers.
[0026] At least one repeating unit of Chemical Formulas B1, B2, and
B3 in the AH-PVA resin is introduced in a range of 0.1 mol % to 50
mol % of the PVA resin, preferably, in a range of 0.1 mol % to 20
mol %, and more preferably, in a range of 0.1 mol % to 10 mol %
with respect to 100 mol % of total PVA resin. When the introduced
amount of at least one repeating unit of Chemical Formulas B1, B2,
and B3 in the PVA resin is less than 0.1 mol %, there may be no
increases in adhesion, humidity resistance, and water resistance
effects by the introduction of the repeating unit. When the
introduced amount is more than 50 mol %, solubility with respect to
water may be reduced and adhesion may rather decrease.
[0027] The AH-PVA may be obtained from a modification reaction of a
polyvinyl alcohol-based resin by a compound having epoxy and
acrylic groups. The polyvinyl alcohol-based resin (hereinafter,
referred to as the `PVA`) is not particularly limited and any
polyvinyl alcohol-based resin known in the art may be used as long
as it is used in a typical adhesive for polarizer and protective
film. Types of the polyvinyl alcohol-based resin are not
particularly limited. Examples of the polyvinyl alcohol-based resin
may be a polyvinyl alcohol resin or a modified polyvinyl alcohol
resin which the polyvinyl alcohol resin is modified with at least
one selected from the group consisting of an acetoacetyl group, a
carboxylic acid group, an acrylic group, or a urethane group.
However, the polyvinyl alcohol-based resin is not limited thereto.
When the modified polyvinyl alcohol resin (modified PAV) which the
polyvinyl alcohol resin is modified with at least one selected from
the group consisting of an acetoacetyl group, a carboxylic acid
group, an acrylic group, or a urethane group is used, the polyvinyl
alcohol resin can be modified with at least one selected from the
group consisting of an acetoacetyl group, a carboxylic acid group,
an acrylic group, or a urethane group at most 15 mol %, preferably
in a range of 0.01 mol % to 15 mol %, more preferably in a range of
0.5 mol % to 8 mol % of the polyvinyl alcohol resin. However, the
PVA is not limited thereto. The PVA may include the repeating unit
C of Chemical Formulas I to III. The modified PVA which is modified
with at least one of an acetoacetyl group, a carboxylic acid group,
an acrylic group, or a urethane group, and the foregoing
modification mol % are common in the art.
[0028] Average degrees of polymerization of the polyvinyl
alcohol-based resin and modified polyvinyl alcohol-based resin
(AH-PVA resin) used in the foregoing reaction may be in a range of
500 to 1800. When the average degrees of polymerization are in a
range of 500 to 1800, excellent physical properties in terms of
viscosity, solid content, and adhesion according to an amount of
use are obtained.
[0029] Meanwhile, a number-average molecular weight (Mn) of the
polyvinyl alcohol-based resin used in the foregoing reaction may be
3000 to 12000, and/or a weight-average molecular weight (Mw) of the
polyvinyl alcohol-based resin used in the foregoing reaction may be
20000 to 100000. The PVA having the foregoing ranges of the
number-average and/or weight-average molecular weights is
appropriate for use as an adhesive in terms of viscosity as well as
having sufficient water resistance after cross-linking.
[0030] A compound of the following Chemical Formula 1 or 2 may be
used as the compound having epoxy and acrylic groups.
##STR00005##
[0031] (In Chemical Formulas 1 and 2, R.sup.1 is substituted or
unsubstituted C.sub.1-C.sub.20 alkandiyl, preferably,
C.sub.1-C.sub.15 alkandiyl, more preferably, C.sub.1-C.sub.10
alkandiyl, further preferably, C.sub.1-C.sub.5 alkandiyl, a
substituted or unsubstituted 1- to 7-membered cyclic group, a
substituted or unsubstituted 1- to 7-membered heterocyclic group
including a heteroatom selected from the group consisting of N, S,
or O, a substituted or unsubstituted C.sub.6-C.sub.14 aromatic
group, or a substituted or unsubstituted 1- to 7-membered
heteroaromatic group including at least one heteroatom selected
from the group consisting of N, S, or O. R.sup.2 is a substituted
or unsubstituted C.sub.1-C.sub.20 alkyl group, preferably, a
C.sub.1-C.sub.15 alkyl group, more preferably, C.sub.1-C.sub.10
alkyl group, further preferably, a C.sub.1-C.sub.5 alkyl group, a
substituted or unsubstituted 1- to 7-membered cyclic group, a
substituted or unsubstituted 1- to 7-membered heterocyclic group
including at least one heteroatom selected from the group
consisting of N, S, or O, a substituted or unsubstituted
C.sub.6-C.sub.14 aromatic group, or a substituted or unsubstituted
1- to 7-membered heteroaromatic group including a heteroatom
selected from the group consisting of N, S, or O. When R.sup.1 and
R.sup.2 are substituted with a substituent, the substituent is a
C.sub.1-C.sub.20 alkyl group, preferably, a C.sub.1-C.sub.15 alkyl
group, more preferably, a C.sub.1-C.sub.10 alkyl group, further
preferably, a C.sub.1-C.sub.5 alkyl group, a halogen atom selected
from the group consisting of F, Cl, Br, or I, a 1- to 7-membered
cyclic group, a 1- to 7-membered heterocyclic group including at
least one heteroatom selected from the group consisting of N, S, or
O, a C.sub.6-C.sub.14 aromatic group, or a 1- to 7-membered
heteroaromatic group including at least one heteroatom selected
from the group consisting of N, S, or O.
[0032] The AH-PVA resin according to an embodiment of the present
invention may be prepared as the following Reaction Formulas 1 to
3.
##STR00006## ##STR00007##
[0033] Reaction Formulas 1 to 3 represent processes of converting
the polyvinyl alcohol-based resins to the AH-PVA resins and the
numbers of repeating units are not described therein. Chemical
Formula 3 in Reaction Formulas 1 to 3 is a polyvinyl alcohol-based
resin and a polyvinyl alcohol resin or a modified polyvinyl
alcohol-based resin in which a polyvinyl alcohol resin is modified
with at least one selected from the group consisting of an
acetoacetyl group, a carboxylic acid group, an acrylic group, or a
urethane group may be used therefor. When the polyvinyl alcohol
resin that is not modified with an acetoacetyl group, a carboxylic
acid group, an acrylic group, or a urethane group is used as the
polyvinyl alcohol-based resin, the repeating unit C does not exist
in Chemical Formula 3.
[0034] In the reactions between PVA of Chemical Formula 3 and a
compound having epoxy and acrylic groups of Chemical Formula 1 or 2
as shown in Reaction Formulas 1 to 3, an OH group of PVA and/or a
R.sup.3 group attack an epoxy group, and then an acrylic group is
introduced into the PVA resin by means of an epoxy ring-opening
reaction and a hydroxyl group (--OH) is formed at the same time.
The epoxy ring-opening reaction is conducted in a basic or acidic
condition. Particularly, in the epoxy ring-opening reaction,
nucleophiles attack less hindered carbons under a basic condition
and attack more hindered carbons under an acidic condition.
Therefore, when the compound of Chemical Formula 1 is used as the
compound having epoxy and acrylic groups, the reaction is performed
like Reaction Formula 1 under a basic condition and is performed
like Reaction Formula 2 under an acidic condition.
[0035] Meanwhile, when the compound of Chemical Formula 2 is used
as the compound having epoxy and acrylic groups, the reaction may
be performed by attacking any of two C--O bonds of an epoxy ring
and opening of the epoxy ring because steric hindrance of
cyclohexane combined with an epoxy group with respect to carbon is
not much different.
[0036] Particularly, as shown in Reaction Formulas 1 to 3, a
polyvinyl alcohol resin (Chemical Formula 3) and a compound having
epoxy and acrylic groups (Chemical Formula 1 or 2) are dissolved in
water and react at a temperature range of room temperature (e.g.,
about 20.degree. C. to 25.degree. C.) to 70.degree. C. for 10 hours
to 30 hours such that a polyvinyl alcohol-based resin in which an
acrylic group is introduced thereto and an --OH group is formed at
the same time with the introduction of an acrylic group (Chemical
Formulas I to III) may be obtained. The amount of water is not
defined and is controlled properly by a person skilled in this art
based on the generally known for a copolymerization (modification
reaction). Meanwhile, the reaction condition has to be controlled
to a basic or an acidic condition. When the reaction is performed
under a basic condition, a pH is controlled to a range of 13 to 14
by means of NaOH, KOH, etc. However, the pH control is not limited
thereto. When the reaction is performed under an acidic condition,
a pH is controlled to a range of 1 to 2 by means of HCl,
H.sub.2SO.sub.4, HNO.sub.3, etc. However, the pH control is not
limited thereto.
[0037] By the foregoing reaction, the polyvinyl alcohol-based resin
in which an acrylic group is introduced into a backbone of the
resin and an --OH group is formed at the same with the introduction
of the acrylic group are obtained. Thus, the polyvinyl
alcohol-based resin, in which an acrylic group is introduced into a
single backbone of a resin and an --OH group is formed at the same
time, has excellent adhesion, water resistance, and humidity
resistance as well as having excellent solubility with respect to
water because adhesion, water resistance, and humidity resistance
provided by the acrylic group and solubility with respect to water
provided by the hydroxyl group are complimentarily optimized.
[0038] Therefore, in another aspect of the present invention, an
adhesive including the AH-PVA resin, particularly an adhesive for a
polarizing plate, is provided.
[0039] In another aspect of the present invention, an adhesive for
a polarizing plate including 100 parts by weight of a polyvinyl
alcohol-based resin and 0.001 to 10 parts by weight of a compound
having epoxy and acrylic groups, for example, 0.001 to 1 part by
weight of a compound having epoxy and acrylic groups, is also
provided. The adhesive including the polyvinyl alcohol-based resin
and the compound having epoxy and acrylic groups in a small amount
also has improved solubility with respect to water and has
excellent adhesion, water resistance, and humidity resistance.
[0040] A polyvinyl alcohol-based resin used in an adhesive
including a polyvinyl alcohol-based resin and a compound having
epoxy and acrylic groups provided from another embodiment of the
present invention is also not particularly limited like the
polyvinyl alcohol-based resin used during the preparation of the
AH-PVA resin, and any polyvinyl alcohol-based adhesive known in the
art may be used as long as it is typically used for the adhesion of
polarizer and protective film. That is, any polyvinyl alcohol-based
resin may be used as long as it may be used during the preparation
of the AH-PVA resin, and all the foregoing descriptions may be
applied identically.
[0041] The compound of Chemical Formula 1 or 2 may be used as the
compound having epoxy and acrylic groups. When a content of the
compound having epoxy and acrylic groups is less than 0.001 parts
by weight with respect to 100 parts by weight of the polyvinyl
alcohol-based resin, there are no increases of adhesiveness,
humidity resistance, and water resistance effects due to the
introduction of the acrylic group. When the content of the compound
having epoxy and acrylic groups is more than 10 parts by weight
with respect to 100 parts by weight of the polyvinyl alcohol-based
resin, an adhesive for a uniform polarizing plate is not obtained
due to the reduction of solubility with respect to water, and
solution stability and adhesion may be low.
[0042] An adhesive for a polarizing plate according to an
embodiment of the present invention is a water-based adhesive which
may be prepared by dissolving the AH-PVA resin or the PVA resin and
compound having epoxy and acrylic groups in water.
[0043] A curing initiator may be further added to the adhesive for
a polarizing plate if necessary.
[0044] A 2,2'-azo-bis(isobutyronitrile) (AIBN)-based initiator, a
persulfate-based initiator, and a Ciba-Geiger AG Darocure and/or
Igacure series initiator may be used as a curing initiator. Any
initiator known in the art may be used as the AIBN or the
persulfate-based initiator as long as it is used as a water base.
Examples of the AIBN-based initiator may be
2,2'-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride,
2,2'-azobis[2-(2-imidazolin-2-yl)propane]disulfate dihydrate,
2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamide],
2,2'-azobis[2-(3,4,5,6-tetrahydropyrrimidin-2-yl)propane]dihydrochloride,
2,2'-azobis(2-[1-(2-hydroxyethyl)-2-yl]propane)dihydrochloride,
2,2'-azobis{2-methyl-N-[2-(hydroxybuthyl)]propionamide},
2,2'-azobis{2-methyl-N-[2-(hydroxyethyl)]propionamide},
2,2'-azobis(N-buthyl-2-methylpropionamide), etc. However, the
AIBN-based initiator is not limited thereto. Examples of the
persulfate-based initiator may be potassium persulfate, ammonium
persulfate, etc. However, the persulfate-based initiator is not
limited thereto. Examples of the Ciba-Geigy AG Darocure and/or
Igacure series initiator may be
hydroxy-1-[4-(hydroxyethoxy)phenol]-2-methyl-1-propanone (Darocure
2959), 2-hydroxy-2-methyl-1-phenylpropane-1-on (Darocure 1173),
1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-on (Darocure
1116), a mixture of
bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentyl phosphine oxide
and 2-hydroxy-2-methyl-1-phenylpropane-1-on in a weight ratio of
25:75 (Irgacure 1700),
1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-di-2-methyl-1-propane-1-on
(Irgacure 2959), 1-hydroxycyclohexylphenylketone (Irgacure 184),
2,2-dimethoxy-2-phenylacetophenone (Irgacure 651), etc. However,
the Ciba-Geigy AG Darocure and/or Igacure series initiator is not
limited thereto.
[0045] The curing initiator may be added to the adhesive for a
polarizing plate in a maximum of 10 wt % based on a total weight of
the adhesive. The curing initiator is a component added optionally
as needed, and although a lower limit of an added amount is not
limited, the curing initiator may be added in a range of 0.01 wt %
to 10 wt %, for example, in a range of 0.01 wt % to 1 wt % based on
the total weight of the adhesive. When the added amount of the
curing initiator is less than 0.01 wt %, effects due to the
addition of the curing initiator are insufficient, and when the
added amount of the curing initiator is more than 10 wt %, the
additive remaining after the reaction may have an adverse effect on
adhesion.
[0046] Various coupling agents, a cross-linking agent, a tackifier,
an ultraviolet absorber, an antioxidant, or various stabilizers
that are generally used in the adhesive for a polarizing plate may
be combined with the adhesive if necessary. The use amounts thereof
are also common in the art and appropriate amounts may be added as
needed by those skilled in the art.
[0047] In the adhesive for a polarizing plate, a concentration of
the polyvinyl alcohol-based resin is in a range of 1 wt % to 50 wt
%, and for example, may be in a range of 1 wt % to 20 wt %
(particularly, a concentration of the AH-PVA in the adhesive
including the AH-PVA and a concentration of the polyvinyl
alcohol-based resin in the adhesive including the polyvinyl
alcohol-based resin and the compound having epoxy and acrylic
groups). An adhesive having a polyvinyl alcohol-based resin
concentration of 1 wt % to 50 wt % may have appropriate viscosity
in terms of coverage and handling of the adhesive as well as
adhesiveness.
[0048] Polarizer and protective films are bonded together by using
the adhesive for a polarizing plate. The adhesive for a polarizing
plate may be used for bonding any polarizer and protective film
generally known in the art. For example, a polyvinyl alcohol-based
resin polarizer is generally used as the polarizer. However, the
polarizer is not limited thereto. Any polymer film having excellent
optical transparency, mechanical strength, thermal stability,
isotropy, adhesiveness to the PVA polarizer may be used as the
protective film. Examples of the protective film may be a film
formed of a polyester-based polymer such as polyethylene
terephthalate or polyethylene naphthalate, a styrene-based polymer
such as polystyrene or a copolymer of acrylonitrile and styrene, a
cellulose-based polymer such as diacetyl cellulose or triacetyl
cellulose, a polyethersulfone-based polymer, a polycarbonate-based
polymer, an acrylic-based polymer such as polymethylmethacrylate, a
polyolefin-based polymer such as polyethylene, polypropylene, a
copolymer of ethylene and propylene, an amide-based polymer such as
nylon or aromatic polyamide, an imide-based polymer, a
sulfone-based polymer, a polyetheretherketone-based polymer, a
polyphenylene sulfide-based polymer, a vinyl alcohol-based polymer,
a vinylidene chloride-based polymer, a vinyl butyral-based polymer,
an arylate-based polymer, a polyoxymethylene-based polymer, an
epoxy-based polymer, and mixtures thereof. However, the protective
film is not limited thereto.
[0049] Particularly, a cellulose-based film such as a cellulose
ester film, a triacetyl cellulose film (TAC film), a cellulose
propionate film, a cellulose acetate propionate film, a cellulose
diacetate film, a cellulose acetate butylate film, a
polycarbonate-based film (PC film), a polystyrene-based film, a
polyarylate-based film, a norbornene resin-based film, or a
polysulfone-based film may be used in consideration of
transparency, mechanical properties, free of optical anisotropy,
etc. A triacetyl cellulose film (TAC film) or a polycarbonate film
(PC film) may be used because of the ease of film preparation and
good processability. For example, the TAC film may be used because
of polarization properties or durability.
[0050] The protective film may be subjected to a surface
modification treatment in order to improve adhesion with respect to
the polarizer to which the protective film adheres. Specific
examples of the surface treatment may be a corona treatment, a glow
discharge treatment, a flame treatment, an acid treatment, an
alkaline treatment, a plasma treatment, an ultrasonic treatment, an
ultraviolet radiation treatment, etc. However, the surface
modification treatment is not limited thereto. Also, a method of
providing an undercoat layer to the protective film may be used in
order to improve adhesiveness.
[0051] A polarizing plate prepared by bonding the polarizer and the
protective film using the adhesive according to an embodiment of
the present invention has excellent water resistance and humidity
resistance because of the excellent adhesion of the adhesive.
[0052] According to another embodiment of the present invention, a
display device including the polarizing plate according to the
present invention is provided. Examples of the display device may
be a liquid crystal display (LCD) device, an electroluminescent
(EL) display device, a plasma display panel (PDP), etc. However,
the display device is not limited thereto.
[0053] Hereinafter, the present invention is described in more
detail with reference to Examples. However, the following Examples
are provided for an understanding of the present invention, and the
present invention is not limited to the following Examples.
Example 1
[0054] A polyvinyl alcohol resin (average degree of polymerization
of 600, degree of saponification of 95% to 97%, Nippon Synthetic
Chemical Industry Co., Ltd., product Z100) was dissolved in pure
water at 80.degree. C. for 1 hour, and then 60 parts by weight of
glycidylmethacrylate (GMA) was added with respect to 100 parts by
weight of the polyvinyl alcohol resin and stirred overnight at room
temperature. As a result, a reaction like that of Reaction Formula
2 was performed such that GMA was chemically combined with the
polyvinyl alcohol resin. Meanwhile, a pH level was controlled to
about 1 to 2 by adding concentrated HCl during the reaction. An
AH-PVA resin was obtained by separating and drying an obtained
reaction product. Thereafter, the AH-PVA resin was analyzed by
Fourier transform infrared spectroscopy (FT-IR) and the presences
of the introduced acrylate and formed OH-- functional group were
confirmed. Also, a content of the introduced GMA was calculated by
using nuclear magnetic resonance (NMR) and a polyvinyl alcohol
resin was obtained in which 4.5 mol % of GMA was introduced.
[0055] Thereafter, a water-based adhesive was prepared by
dissolving the prepared AH-PVA resin (average degree of
polymerization of 600, degree of saponification of 95% to 97%, GMA
content of 4.5 mol %) in a concentration of 4 wt % in pure water.
The composition, contents, and physical properties of the adhesive
are presented in Table 1 below.
[0056] A 80 .mu.m thick saponified triacetyl cellulose (TAC)
protective film was adhered to one surface of a 75 .mu.m thick
polyvinyl alcohol polarizer using the obtained water-based adhesive
and laminated, and then a polarizing plate was fabricated by drying
at 80.degree. C. for 5 minutes.
[0057] Thereafter, the adhesion, solubility with respect to water,
and water resistance of the polarizing plate were evaluated and are
presented in Table 1 below.
Example 2
[0058] A polyvinyl alcohol resin (average degree of polymerization
of 1700, degree of saponification of 95% to 97%, Nippon Synthetic
Chemical Industry Co., Ltd., product Z320) was dissolved in pure
water at 80.degree. C. for 1 hour, and then 40 parts by weight of
glycidylmethacrylate (GMA) was added with respect to 100 parts by
weight of the polyvinyl alcohol resin and stirred overnight at room
temperature. As a result, GMA was chemically combined with the
polyvinyl alcohol resin according to Reaction Formula 1. Meanwhile,
a pH level was controlled to about 13 to 14 by adding 1N NaOH
during the reaction.
[0059] Thereafter, an AH-PVA resin was analyzed by FT-IR and the
presences of the introduced acrylate and formed OH-functional group
were confirmed. Also, a content of the introduced GMA was
calculated by using NMR and a polyvinyl alcohol resin was obtained
in which 2.0 mol % of GMA was introduced.
[0060] A water-based adhesive was prepared by dissolving the
prepared AH-PVA resin (average degree of polymerization of 1700,
degree of saponification of 95% to 97%, GMA content of 2.0 mol %)
in a concentration of 4 wt % in pure water and by adding 15 parts
by weight of a titanium amine complex (DuPont product TYZOR TE) as
a cross-linking agent with respect to 100 parts by weight of the
polyvinyl alcohol resin. The composition, contents, and physical
properties of the adhesive are presented in Table 1 below.
[0061] Except for using the prepared water-based adhesive, a
polarizing plate was fabricated using the method of Example 1.
Thereafter, the adhesion, solubility with respect to water, and
water resistance of the polarizing plate were evaluated and are
presented in Table 1 below.
Example 3
[0062] A polyvinyl alcohol resin (average degree of polymerization
of 1100, degree of saponification of 99%, Nippon Synthetic Chemical
Industry Co., Ltd., product Z210) was dissolved in pure water at
80.degree. C. for 1 hour, and then 5 parts by weight of
glycidylmethacrylate (GMA) was added with respect to 100 parts by
weight of the polyvinyl alcohol resin and stirred overnight at room
temperature. As a result, GMA was chemically combined with the
polyvinyl alcohol resin according to Reaction Formula 1. Meanwhile,
a pH level was controlled to about 1 to 2 by adding concentrated
HCl during the reaction.
[0063] Thereafter, an AH-PVA resin was analyzed by FT-IR and the
presences of the introduced acrylate and formed OH-- functional
group were confirmed. Also, a content of the introduced GMA was
calculated by using NMR and a polyvinyl alcohol resin was obtained
in which 0.15 mol % of GMA was introduced.
[0064] A water-based adhesive was prepared by dissolving the
prepared AH-PVA resin (average degree of polymerization of 1100,
degree of saponification of 99%, GMA content of 0.15 mol %) in a
concentration of 4 wt % in pure water. The composition, contents,
and physical properties of the adhesive are presented in Table 1
below.
[0065] Except for using the prepared water-based adhesive, a
polarizing plate was fabricated using the method of Example 1.
Thereafter, the adhesion, solubility with respect to water, and
water resistance of the polarizing plate were evaluated and are
presented in Table 1 below.
Example 4
[0066] A polyvinyl alcohol resin (average degree of polymerization
of 600, degree of saponification of 95% to 97%, Nippon Synthetic
Chemical Industry Co., Ltd., product Z100) was dissolved in pure
water at 80.degree. C. for 1 hour, and then 60 parts by weight of
glycidylmethacrylate (GMA) was added with respect to 100 parts by
weight of the polyvinyl alcohol resin and stirred at 70.degree. C.
for 24 hours. As a result, GMA was chemically combined with the
polyvinyl alcohol resin according to Reaction Formula 1. Meanwhile,
a pH level was controlled to about 13 to 14 by adding 1N NaOH
during the reaction.
[0067] Thereafter, an AH-PVA resin was analyzed by FT-IR and the
presences of the introduced acrylate and formed OH-functional group
were confirmed. Also, a content of the introduced GMA was
calculated by using NMR and a polyvinyl alcohol resin was obtained
in which 10.0 mol % of GMA was introduced.
[0068] A water-based adhesive was prepared by dissolving the
prepared AH-PVA resin (average degree of polymerization of 600,
degree of saponification of 95% to 97%, GMA content of 10.0 mol %)
in a concentration of 4 wt % in pure water and by adding 15 parts
by weight of a titanium amine complex (DuPont product TYZOR TE) as
a cross-linking agent with respect to 100 parts by weight of the
polyvinyl alcohol resin. The composition, contents, and physical
properties of the adhesive are presented in Table 1 below.
[0069] Except for using the prepared water-based adhesive, a
polarizing plate was fabricated using the method of Example 1.
Thereafter, the adhesion, solubility with respect to water, and
water resistance of the polarizing plate were evaluated and are
presented in Table 1 below.
Example 5
[0070] A polyvinyl alcohol resin (average degree of polymerization
of 1700, degree of saponification of 95% to 97%, Nippon Synthetic
Chemical Industry Co., Ltd., product Z320) was dissolved in pure
water at 80.degree. C. for 1 hour, and then a mixture of GMA and
the polyvinyl alcohol resin was prepared by adding 0.001 parts by
weight of GMA with respect to 100 parts by weight of the dissolved
polyvinyl alcohol resin at room temperature. Thereafter, a
water-based adhesive was prepared by dissolving the obtained
mixture of GMA and polyvinyl alcohol resin in a concentration of 4
wt % (polyvinyl alcohol resin concentration of about 4 wt %) in
pure water and by adding 20 parts by weight of a titanium amine
complex (DuPont product TYZOR TE) as a cross-linking agent with
respect to 100 parts by weight of the polyvinyl alcohol resin.
[0071] Except for using the prepared water-based adhesive, a
polarizing plate was fabricated using the method of Example 1.
Thereafter, the adhesion, solubility with respect to water, and
water resistance of the polarizing plate were evaluated and are
presented in Table 1 below.
Example 6
[0072] A polyvinyl alcohol resin (average degree of polymerization
of 1100, degree of saponification of 99%, Nippon Synthetic Chemical
Industry Co., Ltd., product Z210) was dissolved in pure water at
80.degree. C. for 1 hour, and then a mixture of GMA and the
polyvinyl alcohol resin was prepared by adding 1.0 part by weight
of GMA with respect to 100 parts by weight of the dissolved
polyvinyl alcohol resin at room temperature. Thereafter, a
water-based adhesive was prepared by dissolving the obtained
mixture of GMA and polyvinyl alcohol resin in a concentration of 4
wt % (polyvinyl alcohol resin concentration of about 4 wt %) in
pure water.
[0073] Except for using the prepared water-based adhesive, a
polarizing plate was fabricated using the method of Example 1. The
adhesion, solubility with respect to water, and water resistance of
the polarizing plate were evaluated and are presented in Table 1
below.
Example 7
[0074] A polyvinyl alcohol resin (average degree of polymerization
of 600, degree of saponification of 95% to 97%, Nippon Synthetic
Chemical Industry Co., Ltd., product Z100) was dissolved in pure
water at 80.degree. C. for 1 hour, and then a mixture of GMA and
the polyvinyl alcohol resin was prepared by adding 10 parts by
weight of GMA with respect to 100 parts by weight of the dissolved
polyvinyl alcohol resin at room temperature. Thereafter, a
water-based adhesive was prepared by dissolving the obtained
mixture of GMA and polyvinyl alcohol resin in a concentration of 4
wt % (polyvinyl alcohol resin concentration of about 4 wt %) in
pure water.
[0075] Except for using the prepared water-based adhesive, a
polarizing plate was fabricated using the method of Example 1. The
adhesion, solubility with respect to water, and water resistance of
the polarizing plate were evaluated and are presented in Table 1
below.
Example 8
[0076] A water-based adhesive was prepared by dissolving the AH-PVA
resin prepared in Example 2 in pure water in a concentration of 4
wt %, and then by adding an AIBN-based initiator (Wako Pure
Chemical Industries, Ltd. product VA-004) in a concentration of 0.1
wt %.
[0077] Except for using the prepared water-based adhesive, a
polarizing plate was fabricated using the method of Example 1. The
adhesion, solubility with respect to water, and water resistance of
the polarizing plate were evaluated and are presented in Table 1
below.
Example 9
[0078] A water-based adhesive was prepared by dissolving the AH-PVA
resin prepared in Example 2 in pure water in a concentration of 4
wt %, and then by adding ammonium persulfate (Junsei Chemical Co.,
Ltd.) as a sulfate-based initiator in a concentration of 0.1 wt
%.
[0079] Except for using the prepared water-based adhesive, a
polarizing plate was fabricated using the method of Example 1. The
adhesion, solubility with respect to water, and water resistance of
the polarizing plate were evaluated and are presented in Table 1
below.
Example 10
[0080] A water-based adhesive was prepared by dissolving the AH-PVA
resin prepared in Example 1 in pure water in a concentration of 20
wt %, and then by adding
2-hydroxy-1-[4-(hydroxyethoxy)phenol]-2-methyl-1-propanone
(Ciba-Geigy AG product Darocure 2959, D2959) in a concentration of
0.05 wt %.
[0081] Thereafter, a 80 .mu.m thick saponified triacetyl cellulose
(TAC) protective film was adhered to one surface of a 75 .mu.m
thick polyvinyl alcohol polarizer using prepared the water-based
adhesive, and a polarizing plate was fabricated by curing at an
intensity of 15 mW/cm.sup.2 to 20 mW/cm.sup.2 for 5 minutes using a
UV source (EFOS product Novacure). The adhesion, solubility with
respect to water, and water resistance of the polarizing plate were
evaluated and are presented in Table 1 below.
Example 11
[0082] A polyvinyl alcohol resin (average degree of polymerization
of 600, degree of saponification of 95% to 97%, Nippon Synthetic
Chemical Industry Co., Ltd., product Z100) was dissolved in pure
water at 80.degree. C. for 1 hour, and then 60 parts by weight of
3,4-epoxycyclohexylmethyl acrylate (EMA) was added with respect to
100 parts by weight of the polyvinyl alcohol resin and stirred
overnight at room temperature. As a result, a reaction like that of
Reaction Formula 3 was performed such that EMA was chemically
combined with the polyvinyl alcohol resin. An AH-PVA resin was
obtained by separating and drying an obtained reaction product.
Meanwhile, a pH level was controlled to about 1 to 2 by adding
concentrated HCl during the reaction. Thereafter, the AH-PVA resin
was analyzed by FT-IR and the presences of the introduced acrylate
and formed OH-- functional group were confirmed. Also, a content of
the introduced EMA was calculated by using NMR and a polyvinyl
alcohol resin was obtained in which 4.0 mol % of EMA was
introduced.
[0083] Thereafter, a water-based adhesive was prepared by
dissolving the prepared AH-PVA resin (average degree of
polymerization of 600, degree of saponification of 95% to 97%, EMA
content of 4.0 mol %) in a concentration of 4 wt % in pure water.
The composition, contents, and physical properties of the adhesive
are presented in Table 1 below.
[0084] Except for using the prepared water-based adhesive, a
polarizing plate was fabricated using the method of Example 1.
Thereafter, the adhesion, solubility with respect to water, and
water resistance of the polarizing plate were evaluated and are
presented in Table 1 below.
Example 12
[0085] A polyvinyl alcohol resin (average degree of polymerization
of 1700, degree of saponification of 95% to 97%, Nippon Synthetic
Chemical Industry Co., Ltd., product Z320) was dissolved in pure
water at 80.degree. C. for 1 hour, and then 40 parts by weight of
EMA was added with respect to 100 parts by weight of the polyvinyl
alcohol resin and stirred overnight at room temperature. As a
result, a reaction like that of Reaction Formula 3 was performed
such that EMA was chemically combined with the polyvinyl alcohol
resin. Meanwhile, a pH level was controlled to about 13 to 14 by
adding 1N NaOH during the reaction. Thereafter, an AH-PVA resin was
analyzed by FT-IR and the presences of the introduced acrylate and
formed OH-- functional group were confirmed. Also, a content of the
introduced EMA was calculated by using NMR and a polyvinyl alcohol
resin was obtained in which 1.5 mol % of EMA was introduced.
[0086] Thereafter, a water-based adhesive was prepared by
dissolving the prepared AH-PVA resin (average degree of
polymerization of 1700, degree of saponification of 95% to 97%, EMA
content of 1.5 mol %) in a concentration of 4 wt % in pure water
and by adding 15 parts by weight of a titanium amine complex
(DuPont product TYZOR TE) as a cross-linking agent with respect to
100 parts by weight of the polyvinyl alcohol resin. The
composition, contents, and physical properties of the adhesive are
presented in Table 1 below.
[0087] Except for using the prepared water-based adhesive, a
polarizing plate was fabricated using the method of Example 1.
Thereafter, the adhesion, solubility with respect to water, and
water resistance of the polarizing plate were evaluated and are
presented in Table 1 below.
Example 13
[0088] A polyvinyl alcohol resin (average degree of polymerization
of 1100, degree of saponification of 99%, Nippon Synthetic Chemical
Industry Co., Ltd., product Z210) was dissolved in pure water at
80.degree. C. for 1 hour, and then 5 parts by weight of EMA was
added with respect to 100 parts by weight of the polyvinyl alcohol
resin and stirred overnight at room temperature. As a result, a
reaction like that of Reaction Formula 3 was performed such that
EMA was chemically combined with the polyvinyl alcohol resin.
Meanwhile, a pH level was controlled to about 1 to 2 by adding
concentrated HCl during the reaction. Thereafter, an AH-PVA resin
was analyzed by FT-IR and the presences of the introduced acrylate
and formed OH-- functional group were confirmed. Also, a content of
the introduced EMA was calculated by using NMR and a polyvinyl
alcohol resin was obtained in which 0.12 mol % of EMA was
introduced.
[0089] Thereafter, a water-based adhesive was prepared by
dissolving the prepared AH-PVA resin (average degree of
polymerization of 1100, degree of saponification of 99%, EMA
content of 0.12 mol %) in a concentration of 4 wt % in pure water
and by adding 15 parts by weight of a titanium amine complex
(DuPont product TYZOR TE) as a cross-linking agent with respect to
100 parts by weight of the polyvinyl alcohol resin. The
composition, contents, and physical properties of the adhesive are
presented in Table 1 below.
[0090] Except for using the prepared water-based adhesive, a
polarizing plate was fabricated using the method of Example 1.
Thereafter, the adhesion, solubility with respect to water, and
water resistance of the polarizing plate were evaluated and are
presented in Table 1 below.
Example 14
[0091] A polyvinyl alcohol resin (average degree of polymerization
of 600, degree of saponification of 95% to 97%, Nippon Synthetic
Chemical Industry Co., Ltd., product Z100) was dissolved in pure
water at 80.degree. C. for 1 hour, and then 60 parts by weight of
EMA was added with respect to 100 parts by weight of the polyvinyl
alcohol resin and stirred at 70.degree. C. for hours. As a result,
a reaction like that of Reaction Formula 3 was performed such that
EMA was chemically combined with the polyvinyl alcohol resin.
Meanwhile, a pH level was controlled to about 13 to 14 by adding 1N
NaOH during the reaction. Thereafter, an AH-PVA resin was analyzed
by FT-IR and the presences of the introduced acrylate and formed
OH-functional group were confirmed. Also, a content of the
introduced EMA was calculated by using NMR and a polyvinyl alcohol
resin was obtained in which 9 mol % of EMA was introduced.
[0092] Thereafter, a water-based adhesive was prepared by
dissolving the prepared AH-PVA resin (average degree of
polymerization of 600, degree of saponification of 95% to 97%, EMA
content of 9 mol %) in a concentration of 4 wt % in pure water and
by adding 15 parts by weight of a titanium amine complex (DuPont
product TYZOR TE) as a cross-linking agent with respect to 100
parts by weight of the polyvinyl alcohol resin. The composition,
contents, and physical properties of the adhesive are presented in
Table 1 below.
[0093] Except for using the prepared water-based adhesive, a
polarizing plate was fabricated using the method of Example 1.
Thereafter, the adhesion, solubility with respect to water, and
water resistance of the polarizing plate were evaluated and are
presented in Table 1 below.
Example 15
[0094] A polyvinyl alcohol resin (average degree of polymerization
of 1700, degree of saponification of 95% to 97%, Nippon Synthetic
Chemical Industry Co., Ltd., product Z320) was dissolved in pure
water at 80.degree. C. for 1 hour, and then a mixture of EMA and
the polyvinyl alcohol resin was prepared by adding 0.001 parts by
weight of EMA with respect to 100 parts by weight of the polyvinyl
alcohol resin at room temperature. Thereafter, a water-based
adhesive was prepared by dissolving the obtained mixture of EMA and
polyvinyl alcohol resin in a concentration of 4 wt % (polyvinyl
alcohol resin concentration of about 4 wt %) in pure water and by
adding 20 parts by weight of a titanium amine complex (DuPont
product TYZOR TE) as a cross-linking agent with respect to 100
parts by weight of the polyvinyl alcohol resin.
[0095] Except for using the prepared water-based adhesive, a
polarizing plate was fabricated using the method of Example 1.
Thereafter, the adhesion, solubility with respect to water, and
water resistance of the polarizing plate were evaluated and are
presented in Table 1 below.
Example 16
[0096] A polyvinyl alcohol resin (average degree of polymerization
of 1100, degree of saponification of 99%, Nippon Synthetic Chemical
Industry Co., Ltd., product Z210) was dissolved in pure water at
80.degree. C. for 1 hour, and then a mixture of EMA and the
polyvinyl alcohol resin was prepared by adding 1.0 part by weight
of EMA with respect to 100 parts by weight of the polyvinyl alcohol
resin at room temperature. Thereafter, a water-based adhesive was
prepared by dissolving the obtained mixture of EMA and polyvinyl
alcohol resin in a concentration of 4 wt % (polyvinyl alcohol resin
concentration of about 4 wt %) in pure water.
[0097] Except for using the prepared water-based adhesive, a
polarizing plate was fabricated using the method of Example 1. The
adhesion, solubility with respect to water, and water resistance of
the polarizing plate were evaluated and are presented in Table 1
below.
Example 17
[0098] A polyvinyl alcohol resin (average degree of polymerization
of 600, degree of saponification of 95% to 97%, Nippon Synthetic
Chemical Industry Co., Ltd., product Z100) was dissolved in pure
water at 80.degree. C. for 1 hour, and then a mixture of EMA and
the polyvinyl alcohol resin was prepared by adding 10 parts by
weight of EMA with respect to 100 parts by weight of the dissolved
polyvinyl alcohol resin at room temperature. Thereafter, a
water-based adhesive was prepared by dissolving the obtained
mixture of EMA and polyvinyl alcohol resin in a concentration of 4
wt % (polyvinyl alcohol resin concentration of about 4 wt %) in
pure water.
[0099] Except for using the prepared water-based adhesive, a
polarizing plate was fabricated using the method of Example 1. The
adhesion, solubility with respect to water, and water resistance of
the polarizing plate were evaluated and are presented in Table 1
below.
Example 18
[0100] A water-based adhesive was prepared by dissolving the AH-PVA
resin prepared in Example 12 was dissolved in a concentration of 4
wt % in pure water, and then by adding an AIBN-based initiator
(Wako Pure Chemical Industries, Ltd. product VA-004) in a
concentration of 0.1 wt %.
[0101] Except for using the prepared water-based adhesive, a
polarizing plate was fabricated using the method of Example 1. The
adhesion, solubility with respect to water, and water resistance of
the polarizing plate were evaluated and are presented in Table 1
below.
Example 19
[0102] A water-based adhesive was prepared by dissolving the AH-PVA
resin prepared in Example 12 in a concentration of 20 wt % in pure
water, and then by adding ammonium persulfate (Junsei Chemical Co.,
Ltd.) as a sulfate-based initiator in a concentration of 0.1 wt
%.
[0103] Except for using the prepared water-based adhesive, a
polarizing plate was fabricated using the method of Example 1. The
adhesion, solubility with respect to water, and water resistance of
the polarizing plate were evaluated and are presented in Table 1
below.
Example 20
[0104] A water-based adhesive was prepared by dissolving the AH-PVA
resin prepared in Example 11 in a concentration of wt % in pure
water, and then by adding
2-hydroxy-1-[4-(hydroxyethoxy)phenol]-2-methyl-1-propanone
(Ciba-Geigy AG product Darocure 2959, D2959) in a concentration of
0.05 wt %.
[0105] Thereafter, a 80 .mu.m thick saponified triacetyl cellulose
(TAC) protective film was adhered to one surface of a 75 .mu.m
thick polyvinyl alcohol polarizer using the water-based adhesive,
and a polarizing plate was fabricated by curing at an intensity of
15 mW/cm.sup.2 to 20 mW/cm.sup.2 for 5 minutes using a UV source
(EFOS product Novacure). The adhesion, solubility with respect to
water, and water resistance of the polarizing plate were evaluated
and are presented in Table 1 below.
Example 21
[0106] A polyvinyl alcohol resin (average degree of polymerization
of 1100, degree of saponification of 99%, Nippon Synthetic Chemical
Industry Co., Ltd., product Z210) was dissolved in pure water at
80.degree. C. for 1 hour, and then a mixture of phenylglycidyl
metacrylate (PGMA) of the following Chemical Formula and the
polyvinyl alcohol resin was prepared by adding 0.1 parts by weight
of PGMA with respect to 100 parts by weight of the dissolved
polyvinyl alcohol resin at room temperature. Thereafter, a
water-based adhesive was prepared by dissolving the obtained
mixture of PGMA and polyvinyl alcohol resin in a concentration of 4
wt % (polyvinyl alcohol resin concentration of about 4 wt %) in
pure water.
[0107] Except for using the prepared water-based adhesive, a
polarizing plate was fabricated using the method of Example 1. The
adhesion, solubility with respect to water, and water resistance of
the polarizing plate were evaluated and are presented in Table 1
below.
##STR00008##
Example 22
[0108] A polyvinyl alcohol resin (average degree of polymerization
of 600, degree of saponification of 95% to 97%, Nippon Synthetic
Chemical Industry Co., Ltd., product Z100) was dissolved in pure
water at 80.degree. C. for 1 hour, and then a mixture of
(3H-pyrrol-4-yl)-3,4-epoxycyclohexylmethyl acrylate (PECMA) of the
following Chemical Formula and the polyvinyl alcohol resin was
prepared by adding 0.1 parts by weight of PECMA with respect to 100
parts by weight of the dissolved polyvinyl alcohol resin at room
temperature. Thereafter, a water-based adhesive was prepared by
dissolving the obtained mixture of PECMA and polyvinyl alcohol
resin in a concentration of 4 wt % (polyvinyl alcohol resin
concentration of about 4 wt %) in pure water.
[0109] Except for using the prepared water-based adhesive, a
polarizing plate was fabricated using the method of Example 1. The
adhesion, solubility with respect to water, and water resistance of
the polarizing plate were evaluated and are presented in Table 1
below.
##STR00009##
Comparative Example 1
[0110] A polyvinyl alcohol resin (average degree of polymerization
of 1100, degree of saponification of 99%, Nippon Synthetic Chemical
Industry Co., Ltd., product Z210) with 3 mol % of an acetoacetyl
group introduced was used as a water-based adhesive. Except for
using the water-based adhesive prepared by dissolving the Z210
polyvinyl alcohol resin with the introduced acetoacetyl group in a
concentration of 4 wt % in pure water, a polarizing plate was
fabricated using the method of Example 1. The adhesion, solubility
with respect to water, and water resistance of the polarizing plate
were evaluated and are presented in Table 1 below.
Comparative Example 2
[0111] Except for using an adhesive which is prepared by adding 20
parts by weight of a titanium amine complex (DuPont product TYZOR
TE) as a cross-linking agent to 100 parts by weight of the Z210
polyvinyl alcohol resin with 3 mol % of the introduced acetoacetyl
group of Comparative Example 1, a polarizing plate was fabricated
using the method of Example 1. The adhesion, solubility with
respect to water, and water resistance of the polarizing plate were
evaluated and are presented in Table 1 below.
Comparative Example 3
[0112] Except for using an adhesive which is prepared by adding 20
parts by weight of a zirconium amine complex (Daichi Kigenso Kagaku
Kogyo product AC-7) as a cross-linking agent to 100 parts by weight
of the Z210 polyvinyl alcohol resin with 3 mol % of the introduced
acetoacetyl group of Comparative Example 1, a polarizing plate was
fabricated using the method of Example 1. The adhesion and water
resistance of the polarizing plate were evaluated and are presented
in Table 1 below.
Comparative Example 4
[0113] Except for using an adhesive which is prepared by adding 12
parts by weight of GMA to 100 parts by weight of a polyvinyl
alcohol-based resin (average degree of polymerization of 600,
degree of saponification of 95% to 97%, Nippon Synthetic Chemical
Industry Co., Ltd., product Z100), a polarizing plate was
fabricated using the method of Example 5. The adhesion and water
resistance of the polarizing plate were evaluated and are presented
in Table 1 below.
Comparative Example 5
[0114] Except for using an adhesive which is prepared by adding 11
parts by weight of EMA to 100 parts by weight of a polyvinyl
alcohol-based resin (average degree of polymerization of 1100,
degree of saponification of 99%, Nippon Synthetic Chemical Industry
Co., Ltd., product Z210), a polarizing plate was fabricated using
the method of Example 15. The adhesion, solubility with respect to
water, and water resistance of the polarizing plate were evaluated
and are presented in Table 1 below.
Comparative Example 6
[0115] A polyvinyl alcohol resin (average degree of polymerization
of 1100, degree of saponification of 99%, product of Nippon
Synthetic Chemical Industry Co., Ltd., product Z210) was dissolved
in pure water at 80.degree. C. for 1 hour, and then 30 parts by
weight of acryloyl chloride was added with respect to 100 parts by
weight of the polyvinyl alcohol resin at room temperature. Acryloyl
was chemically combined with the polyvinyl alcohol resin by
stirring at a temperature range of 35.degree. C. to 40.degree. C. A
polyvinyl alcohol resin with the introduced acryloyl group was
obtained by separating and drying an obtained reaction product.
Thereafter, the presence of the introduced acryloyl group was
confirmed by analyzing the obtained polyvinyl alcohol resin with
the introduced acryloyl group with FT-IR. Also, a content of the
introduced acryloyl group was calculated by using NMR.
[0116] Thereafter, a water-based adhesive was prepared by
dissolving the obtained polyvinyl alcohol resin with the introduced
acryloyl group (acryloyl group concentration of 10 mol %) in a
concentration of 4 wt % in pure water.
[0117] Except for using the prepared water-based adhesive, a
polarizing plate was fabricated using the method of Example 1. The
adhesion, solubility with respect to water, and water resistance of
the polarizing plate were evaluated and are presented in Table 1
below.
Comparative Example 7
[0118] An acrylic copolymer solution was obtained through
polymerization in toluene by adding 0.1 parts by weight of benzoyl
peroxide as a polymerization initiator with respect to 100 parts by
weight of a mixture of 2-hydroxyethyl acrylate and acrylic acid in
a weight ratio of 1:1.
[0119] 1.0 part by weight of glycerol diglycidyl ether and 2.0
parts by weight of a zirconium amine compound (Daichi Kigenso
Kagaku Kogyo product AC-7) as a cross-linking agent were added with
respect to 100 parts by weight of a solid content of the copolymer
solution and stirred sufficiently at room temperature for 2 hours,
and then an adhesive was obtained by controlling a solid content of
the copolymer resin to 5 wt %. The solid content of the copolymer
resin was controlled by adding or evaporating toluene.
[0120] Except for using the adhesive solution obtained by the
foregoing method, a polarizing plate was fabricated using the
method of Example 1. The adhesion, solubility with respect to
water, and water resistance of the polarizing plate were evaluated
and are presented in Table 1 below.
[0121] When the adhesive of the present Comparative Example was
used, the adhesion, solubility with respect to water, and water
resistance of the polarizing plate were poor as shown in Table 1
below. Also, after coating the adhesive of this Comparative
Example, toluene was insufficiently removed during a drying process
because toluene as an organic solvent of the adhesive does not
penetrate the polarizer and TAC protective film. Therefore, a
normal polarizing plate was not fabricated.
Comparative Example 8
[0122] 348 parts by weight of 3-hydroxymethyl-3-ethyl oxethane and
348 parts by weight of propylene oxide were mixed, dissolved in 1
liter of diethyl ether, and cooled in an ice bath at -14.degree. C.
Thereafter, 5.5 parts by weight of a 60 wt % HPF.sub.6 aqueous
solution as a polymerization initiator was added dropwise to the
mixed solution for 10 minutes. Subsequently, a reaction was
performed overnight on the mixed solution at room temperature and
the polymerization initiator was deactivated by adding 9 parts by
weight of a 30 wt % NaOCH.sub.3 methanol solution (solution
dissolved in a ratio of 30 g of NaOCH.sub.3 to 70 g of MeOH) on the
next day. A polymerized reaction product was removed by filtration
after the deactivation of the polymerization initiator. Diethyl
ether in a polymerized reaction product was removed by heating at
75.degree. C. and polyether polyol was obtained. The polyether
polyol has an average molecular weight of 3500.
[0123] An adhesive solution having a resin solid content of 5 wt %
was obtained by adding 5.0 parts by weight of glycerol diglycidyl
ether with respect to 100 parts by weight of a polyether polyol
obtained by the foregoing reaction in pure water and by stirring
sufficiently at room temperature for 2 hours. Except for using the
adhesive solution obtained by the foregoing method, a polarizing
plate was fabricated using the method of Example 1. The adhesion,
solubility with respect to water, and water resistance of the
polarizing plate were evaluated and are presented in Table 1
below.
Comparative Example 9
[0124] 5 parts by weight of a copolymer resin copolymerized a
polyvinyl alcohol (average degree of polymerization of 600, degree
of saponification of 95% to 97%, Nippon Synthetic Chemical Industry
Co., Ltd., product Z100) and 2-hydroxyethyl acrylate in a weight
ratio of 85/15 was mixed with 95 parts by weight of water, and then
dissolved by heating. An adhesive (a resin solid content of about
4.8 wt %) was obtained by adding 3.0 parts by weight of a zirconium
amine compound (Daichi Kigenso Kagaku Kogyo product AC-7) as a
cross-linking agent thereto and stirring sufficiently at room
temperature for 2 hours. Except for using the adhesive solution
obtained by the foregoing method, a polarizing plate was fabricated
using the method of Example 1. The adhesion, solubility with
respect to water, and water resistance of the polarizing plate were
evaluated and are presented in Table 1 below.
Comparative Example 10
[0125] A polyvinyl alcohol resin (average degree of polymerization
of 1100, degree of saponification of 99%, Nippon Synthetic Chemical
Industry Co., Ltd., product Z210) was dissolved in pure water at
80.degree. C. for 1 hour, and then a mixture of GMA and the
polyvinyl alcohol resin was prepared by adding 15 parts by weight
of GMA with respect to 100 parts by weight of the dissolved
polyvinyl alcohol resin at room temperature. Thereafter, an
adhesive solution was obtained by dissolving the obtained mixture
of GMA and polyvinyl alcohol resin in pure water to have a
polyvinyl alcohol resin content of 4 wt % and stirring.
[0126] Except for using the adhesive solution obtained by the
foregoing method, a polarizing plate was fabricated using the
method of Example 1. The adhesion, solubility with respect to
water, and water resistance of the polarizing plate were evaluated
and are presented in Table 1 below.
[0127] Physical Property Evaluation
[0128] Physical properties with respect to the adhesives and
polarizing plates of Examples and Comparative Examples were
measured by the following method.
[0129] (1) Fourier Transform Infrared Spectroscopy (FT-IR)
Measurement.
[0130] Absorbance was measured using Excalibur 3100 available from
a Varian, Inc. (USA) and the presence of a modified PVA resin was
confirmed.
[0131] (2) Nuclear Magnetic Resonance (NMR) Measurement.
[0132] A structural analysis of the prepared modified polyvinyl
alcohol resin and a calculation of substitution (modification)
contents were performed by using Unity Inova 500 available from a
Varian, Inc. (USA) Unity Inova 500.
[0133] (3) Adhesion
[0134] Adhesion between the polarizer and protective film in the
polarizing plate was measured by using a texture analyzer (TA,
Stable Micro Systems, UK).
[0135] <Evaluation Criteria>
[0136] .circleincircle.: 5 N/cm.ltoreq.adhesion (adhesion was 5
N/cm or more)
[0137] .smallcircle.: 4 N/cm.ltoreq.adhesion 5 N/cm (adhesion was 4
N/cm or more and less than 5 N/cm)
[0138] .DELTA.: 3 N/cm.ltoreq.adhesion.ltoreq.4 N/cm (adhesion was
3 N/cm or more and less than 4 N/cm)
[0139] X: adhesion<3 N/cm (adhesion was less than 3 N/cm)
[0140] (4) Solubility with Respect to Water
[0141] The adhesive solution compositions of each Example and
Comparative Example were stirred at room temperature for 1 hour,
and then the solubilities of the PVA resins with respect to water
were evaluated visually. The solubilities were evaluated visually
by observing the presence of precipitate formation and the degree
of turbidity. The solubility with respect to water was good when
precipitates are not formed and the aqueous solution was
transparent.
<Evaluation Criteria>
[0142] .smallcircle. (good)--no precipitate, transparent
[0143] .DELTA. (inferior)--no precipitate, turbid
[0144] X (poor)--precipitate formation, turbid
[0145] (5) Water Resistance and Humidity Resistance
[0146] An acrylate adhesive for a polarizing plate was coated on
one surface of a triacetyl cellulose film of a polarizing plate.
The adhesive coated polarizing plate was cut into a size of 50
mm.times.80 mm. At this time, an elongation direction of the
polarizing film was selected as a major axis and the direction
orthogonal thereto was selected as a minor axis. Samples were
prepared by stacking the polarizing plate on glass by the medium of
the coated adhesive, and then water resistance was evaluated.
[0147] Water resistance was evaluated by measuring the degree of
delamination (separation between the protective film and the
polarizer) when the samples were left standing for 8 hours at a
temperature of 60.degree. C. and at a relative humidity of 100%
(use a constant temperature bath).
[0148] An amount peeled from an end of the polarizing plate was
measured and the degree of delamination was confirmed by an area
ratio of the amount of peeling with respect to the sample size. The
smaller the degree of delamination, the better the water
resistance. Results of the physical property evaluations with
respect to the polarizing plates of Examples and Comparative
Examples are presented in Table 1 below.
<Evaluation Criteria>
[0149] .circleincircle. (very good)--delamination area<10%
(delamination area less than 10%)
[0150] .smallcircle. (good)--10%.ltoreq.delamination area<50%
(delamination area 10% or more and less than 50%)
[0151] .DELTA. (inferior)--50%.ltoreq.delamination are <100%
(delamination area 50% or more and less than 100%)
[0152] X (poor)--100% delamination
TABLE-US-00001 TABLE 1 Solubility with respect Water Category
Adhesive composition Adhesion to water resistance Example 1 PVA
with 4.5 mol % of GMA introduced .circleincircle. .largecircle.
.circleincircle. Example 2 PVA with 2.0 mol % of GMA introduced
.circleincircle. .largecircle. .circleincircle. Example 3 PVA with
0.15 mol % of GMA introduced .circleincircle. .largecircle.
.circleincircle. Example 4 PVA with 10 mol % of GMA introduced
.circleincircle. .largecircle. .circleincircle. Example 5 0.001
parts by weight of GMA included .circleincircle. .largecircle.
.circleincircle. Example 6 1.0 part by weight of GMA included
.circleincircle. .largecircle. .circleincircle. Example 7 10 parts
by weight of GMA included .circleincircle. .largecircle.
.circleincircle. Example 8 AH-PVA resin of Example 2/0.1 wt %
.circleincircle. .largecircle. .circleincircle. of an AIBN-based
initiator Example 9 AH-PVA resin of Example 2/0.1 wt %
.circleincircle. .largecircle. .circleincircle. of a sulfate-based
initiator Example 10 AH-PVA resin of Example 1/0.05 wt % of a
.circleincircle. .largecircle. .circleincircle. photoinitiator
Example 11 PVA with 4.0 mol % of EMA introduced .circleincircle.
.largecircle. .circleincircle. Example 12 PVA with 1.5 mol % of EMA
introduced .circleincircle. .largecircle. .circleincircle. Example
13 PVA with 0.12 mol % of EMA introduced .circleincircle.
.largecircle. .circleincircle. Example 14 PVA with 9 mol % of EMA
introduced .circleincircle. .largecircle. .circleincircle. Example
15 0.001 parts by weight of EMA included .circleincircle.
.largecircle. .circleincircle. Example 16 1.0 part by weight of EMA
included .circleincircle. .largecircle. .circleincircle. Example 17
10 parts by weight of EMA included .circleincircle. .largecircle.
.circleincircle. Example 18 AH-PVA resin of Example 12/0.1 wt %
.circleincircle. .largecircle. .circleincircle. of an AIBN-based
initiator Example 19 AH-PVA resin of Example 12/0.1 wt %
.circleincircle. .largecircle. .circleincircle. of a sulfate-based
initiator Example 20 AH-PVA resin of Example 11/0.05 wt % of a
.circleincircle. .largecircle. .circleincircle. photoinitiator
Example 21 0.1 parts by weight of PGMA included .circleincircle.
.largecircle. .circleincircle. Example 22 0.1 parts by weight of
PECMA included .circleincircle. .largecircle. .circleincircle.
Comparative PVA with 3 mol % of an acetoacetyl X .largecircle. X
Example 1 group introduced Comparative 100 parts by weight of the
adhesive resin of .DELTA. .largecircle. .DELTA. Example 2 Example
1/20 parts by weight of TYZOR TE Comparative 100 parts by weight of
the adhesive resin of .DELTA. .largecircle. .largecircle. Example 3
Example 1/20 parts by weight of AC-7 Comparative Include 12 parts
by weight of GMA X X .DELTA. Example 4 Comparative Include 11 parts
by weight of EMA X X .DELTA. Example 5 Comparative PVA resin with
10 mol % of an acryloyl group X X .DELTA. Example 6 introduced
(degree of polymerization of PVA 1100) Comparative Polyacrylate
resin X X X Example 7 Comparative Polyether polyol adhesive resin X
.DELTA. .DELTA. Example 8 Comparative Copolymer resin of PVA and
2-hydroxyethyl .DELTA. .largecircle. X Example 9 acrylate
Comparative 100 parts by weight of PVA/15 parts by weight .DELTA.
.largecircle. X Example 10 of a GMA
[0153] As shown in Table 1, it may be confirmed that the adhesive
for a polarizing plate according to the present invention has
excellent properties of adhesion, solubility with respect to water,
and water resistance.
[0154] While the present invention has been shown and described in
connection with the exemplary embodiments, it will be apparent to
those skilled in the art that modifications and variations can be
made without departing from the spirit and scope of the invention
as defined by the appended claims.
* * * * *