Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Compositions to be polymerized by wave energy wherein said...
Reexamination Certificate
2000-06-01
2002-04-23
Berman, Susan W. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Compositions to be polymerized by wave energy wherein said...
C522S181000, C526S245000
Reexamination Certificate
active
06376572
ABSTRACT:
The present invention relates to compositions which allow to obtain films having improved antireflection properties combined with good no dirt pick up surface properties, good hardness and abrasion-resistance and good chemical resistance (resistent to solvents).
It is known that in order to obtain a film having antireflection properties refractive index of the film must be lower than that of the substratum on which the film is applied. For this purpose films formed of fluorine containing polymers are particularly preferred, wherein it is known that the antireflection properties improve by increasing the fluorine content. See for example the Japanese patent application JP 63068542.
In the prior art, as antireflection films, films formed of fluoropolymers based on fluorinated mono-, bi- or polyfunctional methacrylates, or amorphous perfluoropolymers such as CYTOP® or TEFLON AF®, or TFE-, VDF- or HFP-based polymers or copolymers, have been used.
In the prior art it is also known that in order to obtain films wherein the antireflection effect is combined with good mechanical properties, it is necessary to use crosslinked polymers.
EP 863.128 describes antireflection films obtained by polyfunctional acrylates and methacrylates containing fluorine, wherein the antireflection properties combine with good mechanical properties when the refractive index n
D
of the film is higher than about 1.44. The materials on which the film is applied are transparent, and have refractive index of 1.55 or higher. No reference is made to the film surface properties as above mentioned.
In conclusion in the prior art polymer materials having antireflection characteristics, but not optimal in all the visible field, have been described, and besides a material having the combination of the above mentioned properties was not available.
The need was felt to have available crosslinkable materials having a low refractive index, with which it was possible to prepare films such as to confer substantially uniform antireflection properties in the whole visible field, for applications both to organic polymers with refractive index higher than or equal to 1.55, such as for example polyethylenterephthalate PET (n
D
1.58) and polycarbonate (n
D
1.55), and to those having a lower refractive index, such as for example polymethylmethacrylate PMMA (n
D
1.44), said films combining improved antireflection properties with the following features:
good surface no dirt pick up properties, i.e. dirt is unlikely absorbed and can be easily removed,
good mechanical properties, specifically the abrasion-resistance,
improved chemical resistance, intended as resistance to atmospheric agents and resistance to solvents.
These property combinations are obtained by using the compositions according to the present invention.
The present invention relates to the use of resins or crosslinkable polymers having a low refractive index, lower than 1.400, preferably in the range 1.310-1.390, formed of perfluoropolyether chains with terminal functions of acrylic, methacrylic and hydroxyl type, said resins able to give crosslinked polymer films having a thickness in the range 0.1-100 microns, preferably 1-10 microns with the above mentioned properties.
An object of the present invention is the use of a composition for preparing by radical route polymer films having the above mentioned antireflection properties, said composition comprising:
a) a perfluoropolyether of the following formula:
T′—R
f−
T (Ia)
wherein:
T and T′, equal to or different from each other, are selected from the following groups:
—CF
2
—CH
2
—O—CO—CR═CH
2
,
—CF
2
—CH
2
—O—CO—R
I
—CR═CH
2
wherein:
R=H, CH
3
;
R
I
=—NH—CH
2
—CH
2
—O—CO— or NH—R
II
—NHCOO—CH
2
—CH
2
—OCO—
R
II
being an aliphatic C
3
-C
10
, C
5
-C
14
cycloaliphatic or alkylcycloaliphatic, C
6
-C
14
aromatic or alkylaromatic radical; such as for example C
6
H
12
, hexamethylendiisocyanate aliphatic radical; C
10
H
18
, isophorondiisocyanate cycloaliphatic radical; C
13
H
22
, dicyclohexylmethandiisocyanate radical; C
7
H
6
, 2,6-toluendiisocyanate aromatic radical; C
13
H
10
, diphenylmethandiisocyanate radical;
R
f
is a fluoropolyether having a number average molecular weight from 400 to 5,000, preferably from 700 to 2,000, and it is selected from those having one or more of the following units statistically distributed along the chain: (C
3
F
6
O), (CFYO) wherein Y is F or CF
3
, (C
2
F
4
O), (CR
4
R
5
CF
2
CF
2
O) wherein R
4
and R
5
are equal to or different from each other and selected from H, Cl and one fluorine atom of the perfluoromethylene unit can be substituted with H, Cl, or (per)fluoroalkyl having for example from 1 to 4 carbon atoms;
b) from 0.1 to 10% by weight, preferably from 1 to 5% by weight, of a perfluoropolyether having the following formula:
T—R
f
—CH
2
OH (Ib)
wherein T and R
f
are as above defined;
c) from 0 to 30% by weight of reactive diluents, i.e., compounds which lower the composition viscosity, selected from the following:
(c1) compounds not containing fluorine, selected from the following:
c1a) mono-, bi-, polyfunctional non fluorinated (meth)acrylic esters, obtained by reaction of (meth)acrylic acid with the following hydroxylated compounds:
aliphatic oligoethers having the hydroxyl group at one or both terminations, formed by (C
t
H
2t
O)
nx
units wherein t is 2 or 3 and nx ranges from 2 to 5; examples of such esters are tripropylenglycoldi(meth)acrylate, diethylenglycoldi(meth)acrylate, ethoxyethoxyethyl(meth)acrylate;
mono-, polyhydroxylated aliphatic alcohols, with a number of hydroxyl functions from 1 to 4, linear or branched, with a number of carbon atoms between 2 and 18; examples of such esters such as for example ethylenglycoldi(meth)acrylate, butandioldi(meth)acrylate, hexandioldi(meth)acrylate, trimethylolpropantri(meth)acrylate, pentaerythritoltri(meth)acrylate, stearyl(meth)acrylate, ethylhexyl (meth)acrylate;
cyclo- or polycycloalipathic alcohols with a number of carbon atoms for each ring between 3 and 6, wherein the ring can optionally be substituted with one or more alkyl groups C
1
-C
3
; an example of isobornyl(meth)acrylate, or
c1b) vinyl monomers, copolymerizable with the above mentioned (meth)acrylic esters c1a), such as for example (meth)acrylic acid, N-vinylpyrrolidone;
(c2) compounds containing fluorine, selected from the following:
c2a) mono(meth)acrylate perfluoropolyethers having the formula:
Y
A
CF
2
OR
f″
CFX
p
CH
2
(OCH
2
CH
2
)
p
OCOCR═CH
2
(Ic2a)
wherein
Y
A
=F, Cl, CF
3
, C
2
F
5
, C
3
F
7
, C
4
F
9
; and X
p
=F, CF
3
; R as above defined wherein p is zero or an integer from 1 to 5; R
f″
represents a radical having a perfluoropolyether structure with a number average molecular weight in the range 400-3,000, said radical being formed of sequences of alkylene oxyfluoro structures, such as for example the following units:
—CF
2
O—, —CF
2
CF
2
O—, —CF
2
CF
2
CF
2
O—, —CF
2
(CF
3
)—CFO—, —(CF
3
)CFO—, —CF
2
CF
2
CH
2
O—;
or
c2b) perfluoroalkyl mono(meth)acrylates of formula:
(R
fI
)
PI
QOCOCH═CH
2
(Ic2b)
wherein
R
fI
is a fluoroalkyl radical with C
3
-C
30
, preferably C
3
-C
20
, carbon atoms or a perfluoropolyether radical PFPE containing in the chain the units above mentioned in c2a) and having a number of carbon atoms from 5 to 30;
pI is 1 or 2;
Q is an aliphatic C
1
-C
12
or aromatic C
6
-C
12
divalent linking bridge; Q can optionally contain heteroatoms such as N, O, S, or carbonylimino, sulphonylimino or carbonyl groups; Q can be unsubstituted or is linked to substitutents selected from the following: halogen atoms, hydroxyl groups, alkyl radicals C
1
-C
6
; Q preferably does not contain double or triple bonds; preferably Q is selected from the following divalent radicals: —CH
2
—, C
2
H
4
—, —SO
2
N(R
5
)C
2
H
4
—, —SO
2
N(R
5
)CH
2
CH(CH
3
)—, —C
2
H
4
SO
2
N(R
5
)C
4
H
8
—, R
5
is H or an alkyl C
1
-C
4
;
d) from 0.01 to 10% by weight of photoinitiator and/or radical initiator
Arent Fox Kintner Plotkin & Kahn
Ausimont S.p.A.
Berman Susan W.
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