Note: Descriptions are shown in the official language in which they were submitted.
FN 30075
1 1556:1 7
SHAPED PLASTIC ARTIGLES HAVING
R LICATED MICROSTRUCTURE SURFACES
This invention relates to the replication of
surfaces bearing microstructure. In another aspect it
relates to shaped plastic articles, such as retroreflecting
cube-corner sheeting, Fresnel lens elements, diffraction
gratings, video discs, and ophthalmic lenses, having
replicated microstructure-bearing surfaces, and to a pro-
cess for the preparation of the articles. In another
aspect, it relates to novel castable radiation curable
oligomers, a process for their preparation, and the use
of such material in making said replicated plastic articles.
Many materials, techniques and processes have
been proposed, patented or used for replicating various
microstructure-bearing surfaces in the form of embossed,
cast or molded plastic articles, e.g., see J. of Applied
: 15 Physics, Vol. 45, No. 10, p. 4557, October, 1974. Some
of these have been of practical value though of limited
application in many instances while others have been
found wanting as impractical, especially where the object
has been high fidelity and durability of replication or
mass production capability. In many cases, the progress
in this art has been stymied by lack of suitable repli-
cating materials.
For example, in the area of retroreflective
cube-corner sheetings, used as traffic signs and the other
applications where light reflection is used for tra~fic
1 15561 7
direction and safety, U.S. Pat. No. 3,689,346 (Rowland)
discloses a process for the continuous replication of such
articles by depositing a crosslinkable,partially poly-
merized resin, such as certain acrylic acid ester resins,
on a negative molding surface to be replicated, and
exposing the resin to actinic light or heat to solidify
the resin. The resins used typically exhibited relatively
high levels of shrinkage upon solidifying or curing, thus
giving rise to optical imperfections in the cube-corner
mierostructure, that is, changes in the angles between
the faces of the cube-corner which produce light scatter-
ing rather than the desired maximum retroreflectivity.
Attempts to overcome such shortcomings are described in
U.S. Pat. No. 3,935,359 (Rowland) which discloses filling
further resin in the void resulting from the shrinkage,
and U.S. Pat. No, 3,980,393 (Heasley et al) which dis-
closes using a lens system in con~unction with the cube-
corner structure in order to compensate for the shrinkage.
Sueh modifieations are, of course, costly and demonstrate
a need for replicating materials which do not significantly
shrink and so cause optical imperfections in the replication.
An example where plastics have been used in
replication of optical surfaces or elements is U.S. Pat.
No. 3,931,373 (Beattie) which discloses replicating
ophthalmic lenses from plastic compositions,such as methyl
methacrylate,by use of a replicating mold made of certain
polymeric materials, such as certain copolymers of styrene
and methyl methacrylate, to prevent distortion of lenses
during cure. French Pat. No. 2,247,329 discloses
1155617
making replicas of video discs using ulkra-violet radia-
tion curable acrylics and epoxies. U.S. Pat. No. 3,334,958
(Appledorn) discloses Fresnel lens elements stamped from
polymerized methyl methacrylate using molds made from
machined master lenses.
Other U.S. patents disclosing replication of
various articles using plastic compositions are U.S. Pat.
Nos. 2,310,790 (Jungerson), 2,482,598 (Roos), 3,565,978
(Folger et al), 3,190,947 (Norcros), 3,369,949 (Forrest)
. .
3,667,946 (Sturderant), 2,524,862 (White)j the replication
process of these patents require high molding temperatures
or pressures which cause loss of fidelity in the replicated
structure, use of solvents which require a long time to
evaporate, long cure cycles, curable materials which have
a limited "pot" life, or result in replicated articles
having limited toughness and dimensional stability and
with severe shrinkage.
Though oligomers or cured polymers with "hard"
and "soft" segments or blocks have been disclosed in the
prior art, e.g., see "Block Copolymers", Allport and Janes,
published by Wiley & Sons, N.E. Chap. 8C, (1973),
"Polymer Blends & Copolymers", Manson & Sperling, pub-
lished by Plenum Press, N.Y., p. 153-166, (1976),
"Polymer Engineering & Science", Vol. 11, No. 4, p. 369,
(1971), "Encyclopedia of Polymer Science & Technology",
Kirk-Othmer, Suppl., Vol. 1, p. 521-543 (1976, and U.S.
Pat. Nos. 3,560,417 (Pizzi et al) and 4,077,932 (Columbus),
those materials have not been disclosed as useful in
making shaped plastic articles comprising crosslinked
polymer and having replicated microstructure surfaces.
1 1~5617
Briefly, in one aspeet, this invention provides an
artiele comprising a shaped, plastie, monolithie layer (or
body) eomprising certain crosslinked polymer and having one
or more, like or different, replicated microstructure-bear-
ing surfaces. An example of such artiele is a traffie con-
trol sign eomprising a layer in the form of a self-support-
ing or free film or sheet of said crosslinked polymer and
having on one side a microstructure-bearing surface in the
form of a replicated array of retrorefleetive eube-corners,
the other side of which sheet can be replieated "flat" sur-
faee. Sueh artieles are prepared by a proeess eomprising
filling a mold master, bearing the mierostrueture to be re-
plieated, with a fluid, eastable, one-part, prefereably sol-
vent-free, radiation addition-polymerizable, erosslinkable,
oligomeric composition (or precursors thereof) having both
"hard" segments and "soft" polysiloxane segments, exposing
the resulting cast composition to radiation, preferably
actinie radiation sueh as ultraviolet radiation, and thereby
forming said article. Said proeess lends itself to rapid,
mass production of sueh artieles with no adverse environmental
impaet beeause no or only a minor amount of solvent or other
volatiles are evolved and it can be carried out at ambient
temperatures and pressures. The process also lends itself to
replieation of artieles with mierostrueture eomprising utili-
tarian discontinuities, such as projeetions and depressions,whieh are readily released from the mold masterwithout -loss of
the detail of the master andwith retentionofthe replieation
ofsuehdetail underawide variety of eonditionsduring use.
The artieles ean beformedwithawide variety ofdesiredpro-
perties, sueh as toughness, flexibility, optieal clarity or
--4--
- 115.~617
homogenity, and resistance to common solvents, the micro-
structure of such articles having high thermal dimensional
stability, resistance to abrasion and impact, and integrity
even when the articles are bent, e.g., 180. The physical
properties of the crosslinked polymer can be varied by pro-
per selection of the oligomeric composition. The tensile
strengths of the polymer can be varied from 70 to 700 kg/cm2,
the modulus of elasticity can be varied from 140 to 14000
kg/cm , and the elongation-to-break can be varied from 5 to
300%. The optical homogenity of the polymer is manifested
by at least 91% transmission of light, haze of less than 5%,
and birefringence, ~n, of less than 0.002, and the flexi-
bility is manifested by desirable dynamic shear moduli over
a wide temperature range, e.g., 23 to 120C.
FIG. 1 is a plot of the dynamic shear moduli of
illustrative plastics used in making plastic articles of
this invention; FIG. 2 is an isometric view of replicated
diffraction gratings of this invention; FIG. 3 is a plan
view of replicated array of cube-corner retroreflective
elements of this invention; FIG. 4 is an elevation section
of FIG. 3 taken along 4-4; FIG. 4A is an elevation section
of a modified retroreflective sheeting employing the array
of FIG. 4; FIG. 5 is a diagrammatic view of a cube-corner
element; FIG. 6 is an isometric view of a sheet of repli-
cated linear Fresnel lenses of this invention; FIG. 7 is anisometric view of a replicated video disc of this invention;
FIG. 8 is an enlarged view of a portion of FIG. 7; FIG. 9 is
a schematic diagram of apparatus useful in making a sheet
of cube-corner elements of FIGS. 3 and 4; and FIGS. lOA-lOI
are diagrams of illustrative profiles of various replicated
microstructures of this invention.
5 -
~,.,
1 15~617
The term "microstructure~', used herein in the con-
text of a shaped article having a surface bearing microstruc-
ture, means the configuration of a surface which depicts or
characterizes the predetermined desired utilitarian purpose
or function of said article. Discontinuities, such as pro-
jections and indentations, in the surface will deviate in
profile from the average profile or center line drawn trhough the
microstructure such that the sum of the areas embraced by
the surface profile above the line is equal to the sum of
those areas below the line, said line being essentially
parallel to the nominal surface (bearing the microstructure)
of the article. The heights of said deviations will be
+ 0.005 ~m to + 750 ~m through a representative character-
istic length of the surrace, e.g., 1 to 30 CM. Said average
profile, or center line, can be plano, concave, convex,
aspheric or combinations thereof. Articles where said de-
viations are of low order, e.g., from + 0.005 ~m to 0.1 ~m
or, preferably, to + 0.05 um, and said deviationsare of
infrequent or minimal occurrence, i.e., the surface is free
of any significant discontinuities, are those where the
microstructure-bearing surface is an essentially "flat" or
"perfectly smooth" surface, such articles being useful, for
example, as precision optical elements or elements with a
precision optical interface, such as ophthalmic lenses.
Articles where said deviations are of said low order and of
frequent occurrence are those, for example, bearing utili-
tarian discontinuities, as in the case of articles having
anti-reflective microstructure. Articles where said devia-
tions are of high order, e.g., from + 0.1 ~m to + 750 ~m,
and attributable to microstructure comprising a plurality of
-- 6 --
1 15561"~
utilitarian discontinuities which are the same or dif~erent
and spaced apart or contiguous in a random or ordered
manner, are articles such as retroreflective cube-corner
sheeting, linear Fresnel lenses, and video discs. The
microstructure-bearing surface can contain utilitarian dis-
continuities of both said low and high orders. The micro-
structure-bearing surface may contain extraneous or non-
utilitarian discontinuities so long as the amounts or
types thereof do not significantly interfere with or
lQ adversely affect the predetermined desired utilities of said
articles. It may be necessary or desirable to select a
particular oligomeric composition whose shrinkage upon
curing does not result in said interfering extraneous dis-
continuities, e.g., a composition which shrinks only 2 to 6%.
The above described profiles and the dimensions
and spacing of said discontinuities are thOse discernible
by an electron microscope at 1000X to 100,000X or an opti-
cal microscope at 10X to 1000X.
In FIGS. 10A - 10I, various illustrative profiles
of replicated microstructure-bearing surfaces are shown.
The profile of FIG. 10A is plano, free of utilitarian dis-
continuities, and is illustrative of the microstructure of
an ophthalmic lens or optical flat. The profiles of FIGS.
10B and 10C have spaced-apart utilitarian discontinuities
which in FIG. 10B are in the form of projection or raised
areas 21 and in FIG. 10C are in the form of depressions or
indentations 22, such profiles being illustrative, for
!
1 1556:1 7
example, of microstructure present on video discs. FIGS.
- lOD and lOE depict profiles with a plurality of con-
tiguous, utilitarian discontinuities, such profiles being
illustrative, for example, of species of anti-reflective
surfaces. FIG. lOF depicts a profile with a plurality of
closely spaced arcs, e.g., hemispherical, and is illustra-
tive of microstructure in the form of utilitarian lenslets,
e.g., a replicated beaded layer which can be vapor coated
with specular light reflecting material to provide a re-
troreflective sheet. FIG. lOG depicts a profile with in-
dividual contiguous utilitarian discontinuities in the
form of pro~ections 23 of like size and shape, and is
illustrative of cube-corner retroreflective microstructure
made up of trihedral prism elements. FIG. lOH depicts a
profile with utilitarian discontinuities in the form of
alternating steps 24 and lands 25, such a profile being
iIlustrative of a linear Fresnel lens. And FIG. lOI depicts
a profile which is a combination of the types illustrated
in FIGS. lOC and lOH, the lands 26 being "rough" due to
low order utilitarian discontinuities, such a profile
being illustrative of a linear Fresnel lens with anti-
reflective microstructure.
Radiation addition-polymerizable, crosslinkable
oligomeric compositions useful in making said shaped arti-
: 25 cles of this invention comprise radiation addition-poly--
merizable, oligomers or prepolymers having (l) one or more
like or different "hard" (rigid) segments ("H"), viz.,
mono- or poly- and preferably di-valent moieties contain-
ing one or more carbocyclic and/or heterocyclic groups and
~ ~5~1~
preferably difunctional linking groups with hydrogen-
bonding capabilities, e.g., carbonyldioxy, -OC(O)O-,
carbamato, -NHC(O)O-, ureylene, -NHCONH-, amido, -NHCO-,
and oxy, -O-, said moieties, when their valences are
satisfied by protons, having at least one major transition
temperature above 250K, prefereably above 350K, said tran-
sition being a glass transition temperature or crystalline
melting point, such as are usually detected by differen-
tial thermal analysis or thermomechanical analysis, (2) one
or more llke or different "soft" (flexible) segments ("S"),
viz., poly-valent polysiloxane moieties which have a number
average molecular weight in the range of about 500 to 5000
and each of which in the form of homopolymer has a glass
transition temperature below 250K, and (3) one or more like
or different monovalent moieties ("E") containing a radiation
sensitive, addition-polymerizable, functional group such
as acrylyl, methacrylyl, allyl or vic-epoxy group. The
amounts of "H", "S" and "E" segments or moieties in said
oligomeric composition are such that the radiation-cured
crosslinked plastic derived therefrom preferably has dynamic
shear moduli, over the temperature range of 23 to 123C,
on or within the boundary of area A-B-C-D of FIG. 1.
Where the oligomers contain two or more "H" segments, such
segments can be the same or different, as is true of the
"S" segments and the "E" moieties. Further, the oligomers
are free of labile groups, viz., -O-O- and -N=N-, and
generally will have a number average molecular weight of
about 1000 to 30,000 grams per mole.
_g_
1 1~5~17
A class of such oligomers can be represented
by the general formula
~E ( E ~Es~ E~ D ~ I
where "E", "H", and "S" are as broadly defined above,
a is 1 or 2, ~ is zero or an integer up to 20 whose
average is less than about 5, and ~ is 2 or 3~
"E" in formula I can be represented by the
formula
CH2=C_~C ~ A ~ CH2 ~ A~d II
where Rl is a hydrogen atom or methyl,
each A is independently -NH- or -O-,
a, b, c and d are each independently zero or 1, with
the provisos that
(1) at least one of b and d must be 1,
(2) if b and c are both zero, then a and d must
be 1,
(3) if b and d are both 1, then a and c must be
1, and e is at least 2, and
(4) if d is 1 and a and b are both zero, then c
must be 1,
e is an integer of 1 to 5,
subgenera of formula II being those of the formulas:
Rl R
CH2=C - C-A- IIA
where preferably Rl is methyl and A is -O-~
10-
B
` - 115561'7
Rl O
CH =C-C-O~CH ~ A- IIB
.i where preferably Rl is methyl, A is -O-, and e is 2,
., Rl
and CH2=C-CH2-A- IIC
where preferably R is a hydrogen atom and A is -O-.
"E" in formula I can also be that represented by the
formulas:
.C~2-fH-~C~2 ~ 0~ III L--'
O
R
B ~ 0~ IV
where (in formulas III and IV)
R2 is hydrogen or a lower alkyl (e.g., with 1 to 4
: carbon atoms and preferably is methyl)~
B is ~CH2~f, -CO-, ~CH2~ CO- or
. ~CH2~fOC ( O )~CH2~C ( O ) O ( CH2~,
~,
and each f is an integer of 2 to 5, each d is in-
dependently zero or 1, and e is 1 to 5.
"H" in formula I can be represented by the
formulas:
-3~A~d R3~A~3--EA_R--A-3~A~d33~A~3~ V
t
~L~ 3 'i
~`` 1155617
~ t NzCNCN20 ~ C ~ ~ CCN2CHCN2~0 1 VI
~~-d ~ ~d VII
and ~ ~ I ~ l5 VIII
h
or, where "E" in formula I is selected from the group of
structures represented by formulas IIA, IIB, and IIC, "H"
can be represented by t~e following structure:
--H2C~ ~CH2 -oR40H2C~ ~CH2--_
(R60)dCH2 ~ Q ~ ~CH20R6 R60H2C ~ ~ CH20R6 IX
N~CH20R ) N(CH2R )2 d
., .
556:l7
:`
where (in formulas V, VI, VII, VIII and IX),
each R is independently as defined above for formula
IV,
each R3 is independently a di-valent carbocyclic-
containing radlcal derived from benzene, napthalene,
cyclohexane, dicyclohexylmethane, diphenylmethane,
or norbornene, and their lower alkyl-substituted
derivatives, by removal of two of their hydrogen
atoms,
each R4 is independently an alkylene moiety with
2 to 10 (and preferably 2, 4 or 6) carbon atoms,
or a cycloalkylene moiety with 6 to 10 carbon atoms
(and preferably 8 carbon atoms, 6 of which are
ring-carbon atoms),
each R5 is independently a phenyl moiety or (prefer-
ably) methyl
each R6 is independently a lower alkyl with 1 to 4
: carbon atoms, preferably methyl,
g is zero or a number up to 5 (and preferably an
average of 1 to 3),
B is as defined in formula IV,
' h is an integer of 1 to 10,
h' is ~ero or an integer of 1 to 10,
each d, d' and d" is independently zero or 1, with
.i 25 the proviso that if either one of d' or d" is 1, :-
then the other is zero, and
A is as defined above for formula II.
"S" in formula I is a polysiloxane residue remaining
after removal of the active hydrogen atoms of polyols
(illustrated by the generic formula RS(OH)y herein-
after) such as polysiloxane polyols, or polysiloxane
polyamines (illustrated by the generic formula RS(NH2)y
hereinafter).
5 6 1 7
"S" in formula I is a said polysiloxane residue repre-
sented by the ~ormulas:
-0-3~5i(CN3)--O~Sl-R-O- XV
where b' is a number of 6 to 35, and R is a linear or
branched alkylene group having 1 to 12 carbon atoms or a
polyoxyalkylene group having 4 to 80 carbon atoms and 1 to
40 oxygen atorns,
and (C~13)3siO ~i(C~13)2 3 F i ~ 1 ( 33)3
where the groups enclosed by the single brackets with
subscripts b' and c' are repeating units randomly dis-
tributed within the double bracket, b' being a number
of 6 to 35 and c' being 2 or 3, and R is as defined
above ~or formula XV.
Representative species of oligorners useful in
making the shaped articles of this invention and falling
within the scope of formula I include those having the
structures represented in Table I.
115~i617
I r~
C~
_ ~ f\l ~ D
U~ ~_ I N
~ O
~ C~J
~ ~ , I ....
'~ ' '
Hl ~ ~ ~ ~
¦ D
_ D
C~
h ~ o H
115~61~
{u
~,, I U~
O ~ ~
o ~
e~
N i.~
_ ~_ ~,N
., O
I I I I ~ l ~
~ ~1 =O
~ ~ A
e~ ~ 0=ol
_ O ~ O
h ~ o , H
--16--
1155617
N O N
. ,~ F F
X~
~ ~X~
~ X~
O
O
r~ ~ o
~ ,,
I tB H
~Z X
115561'~
,~
C~l rl
~ ' ~C\J
o
~ .~
.~ ~ ~
_ L~ ' rl
,~ ,
.,~
,~
P ~ o o~ ~ j?~
O O
l l l l
Z ~
, X
V~ o
X~
~ ~,
~ ~ ~ ~ ,
--18--
-
,. .. .
1 15.~ 1 7
~ ~ N
.~ r~ ~
. j I ' u~ I ~Q ~ >
_ N N
` V C~
,`
C~
~ O
_ O ~ V ~N
_ O ~ ;'
_ tr~ o 5
C~--V
11
~: X C)
.,
I Cd H
h ~ o
19
1155617
Another class of oligomers useful in making the
shaped articles of this invention can be represented by
the general formula:
~'E''''H'')a'S ( ~ S )~] LV
Y
where "E", "H", "S", ~ , ~ and y are as defined for
formula I.
Since representative species of formula LV can be made
with the same "E", "H" and "S" moieties as those species
of formula I listed in TABLE I (though the number and
ratio of such moieties in the species of formula LV can
be different than the number and ratio of such moieties
in the species of TABLE I), we will omit, in the interest
- of brevity, a similar list of representative species of
formula LV.
Other classes of oligomers useful in making
the shaped articles of this invention can be represented
by the general formulas:
~ "("S")~ ~"("S") ~ ;H" LVI
and LEEII ~S ~ ~H~ Es~ sl LVII
where "H", "S", ~, ~ and y are as defined for for-
mula I, but "E" in formulas LVI and VLII is represented
by the formulas:
- 20-
~, .
-" 1155~17
:, 1 0
CH2=C-C~A~ ~ CH2 ~ A~ ~ C~d" LVIII
where Rl is hydrogen or methyl,
each A' and A" is independently -NH- or -O-,
f is an integer of 2 to 5, and
each of b, c, d' and d" are independently zero or l,
with the provisos that (l) if b and c are both zero
then d' and d" are both zero (in which case R is
preferably hydrogen), or (2) if b and c are both l,
then d' and d" are both zero (in which case pre-
ferably Rl is hydrogen, A' is -O-, and f is 2 or 3)
or are both l (in which case preferably Rl is
methyl and f is 2),
R 1 OH
CH2=C_C_O-CH2~HCH2 LIX
where Rl is hydrogen, or preferably, methyl,
Rl o
l5 and C 2 ~~~ 2 ~ ~ d LX
where Rl is methyl or, preferably, hydrogen,
A is -NH- or, preferably, -O-,
e is an integer of l to 5, preferably l, and
d~ and d" are either both zero (in which case
Rl is preferably hydrogen and e is l) or both are l,
(in which case preferably Rl is hydrogen~ A is
-NH- and e is l~.
- 21 -
115561~l
Representative species of oligomers of formula
LVI useful in making the shaped articles of this invention
are set forth in TABLE II, where structural formulas
for the various "E'1, "H" and "S" moieties of said species
have been omitted in the interest of brevity, reference
instead being made to structural formulas for said moieties
which are set out hereinbefore. Representative species
of oligomers of formula LVII can be made with the same
"E", "H", and "S" moieties as those species of formula LVI
listed in Table II (though the number and ratio of such
moieties in the species of formula LVII can be different
than the number and ratio of such moieties in the species
of TABLE II); thus, we will omit, in the interest of
brevity, a similar list of representative species of
formula LVII.
.. ..
~` 1155~7
TABLE II
For-
mula "E" "S" "H"
No.
. . . .
LXIV formula LVIII where XXI XXVIII*
1 and e is 2, R is
-CH~, A' is -O- and
A" ~s -NH-
LXV ditto XXII XXXVI**
LXVII ditto XXII XXVIII*
LXXII ~ormula LIX where Rl XXII XXI
is -CH3
LXXV ditto XXI XXXVI**
LXXVIII formula LX where R1 XXII XXXVI**
is H, A is -NH-, and
d', d" and e are 1
LXXIX ditto XXII L*** and XXI
.~
CH **
-CO~H- ~ CH3H2C ~Q~ CH2 3
~HCO- ~(CH20CH3)
XXVIII
XXXVI
::: Cu
23
.~ .
;
~ 155B 17
The radiation addltlon-polymerizable, crossllnkable
oligomerlc compositlons useful in making the shaped articles of
this lnvention can be prepared by general reactions that are
well-known in the art of preparing addition polymerizable materials.
5 Those general reactions are typically of two types: (1) addition
reactions, viz., the urethane- or urea-forming reaction between
an active hydrogen organic compound and isocyanate or the ether-
forming reaction between an active hydrogen organic compound and
an epoxy compound, and (2) condensation reactions, viz., esteri-
10 fication or etherification of an active hydrogen organic compoundwith a carboxylic acid or ester or acylhalide derivative thereof
or with an alkyl ether, accompanied by elimination of a byproduct;
for the preparation of some oligomeric compositions, both types
of reactions will be employed as shown hereinafter. Such reactions
15 are commonly used in synthetic polymer chemistry, e.g. see
Saunders, J.H. and K. C. Frisch, "Polyurethanes: Chemistry and
Technology", Part 1 (1962), especially Chapter III; Lee, H. and
K. Neville,"Handbook of Epoxy Resins" (1967)~ especially Appendix
5-1; Bruins, P.F., "Epoxy Resin Technology" (1968), especially
20 Chapters 1 and 2; Kirk-Othmer "Encyclopedia of Chemical Technology"
2nd Ed., Vol. 8, p. 313 (1965); Roberts, J.D. and M.C. Caserio,
"Basic Principals of Organic Chemistry", p. 518 (1964). These
general reactions are thus used to chemically combine "E" moietles
with the "H" and "S" segments to form oligomeric compositions of
25 use in the invention. Generally, the combining of the "E", "H" and
"S" moieties is carried out in a sequence of steps; however, under
some circumstances, it is convenient to carry out the reactions
simultaneously and even to form the oligomeric composition in situ
during the process of making the replicated plastlc artlcles of
30 this lnvention, e.g., carrying out the ether-forming addition re-
action in situ in the replication mold.
-- 24 --
~?
.... ..
1 15~617
Generally, the urethane- or urea-formlng reactions are
carried out at temperatures from 25 to 100C for 10 mlnutes to
several hours or more, sufficient to bring about the reactlon.
Preferably, a catalyst such as dibutyltin dllaurate is used to
promote the reaction. Generalized equations for such reactions
ln preparing the oligomeric composition used in this invention
are illustrated as follows where the precursors of "H", "S" and
"E" are denoted by formulas containing such letters as subscripts,
the formula containing C as a subscript being a chain extendlng
compound, and g, ~ and y are as defined for formula I:
;'
(y+~y) RH(NCO)2+(1+~Y)RS(OH)y catalyst
. _ YREOH
_RH_NHcoo(Rs-ocoNH-RH-NHcoo~ RS a
[E-ocoN~I-RH-NHcoo~Rs-ocoNH-RH-NHcoo~Rs ( 1 )
y(l + ~ + g)RH(NC0)2 + (1+ ~y )R (OH)y + ~gRc(OH)2 a ~ y t>
~CN-RH-NHCO ~ O-Rc-OCONH-RH-NHCO) O-(Rs-OCOI~H-RH-NHCOO~ RS
yR OH
E -OCONH-RH-NHCO ~O-Rc-OCONH-RH-NHCO~ O ~ Rs-OCONH-RH-NHCOO~ ~ RS
(2)
- 2~ -
(y+~y)Rs(OH)y + (l~y)RH(NCO)y ca~ t ,~
_ yRENCO
~HO-RS-OCONH~R}~-NHCOO-Rs-OCONH~ RH ~
~RE-NHCOo-Rs-ocoNH-~RH-NHcoo-Rs-ocoNH~ R~l ( 3)
Y BY)RS(NH2)y + (l+~y)RH(NCO) catalyst ~
[2N-RS-NHCONH~R-HNHCONH-Rs; NHCO) ~RH E~ >
r
LE-NHCONH-RS-NHCONH~RH-NHCONH-RS-NHCONH-)~ RH (4)
The ether-forming addition reactions are carried
out generally at temperatures of 75 to 150C (or ambient
temperatures when carried out in situ in the replication
of the plastic articles),preferably in the presence of
catalysts such as Lewis acids, e.g., BF3-0(C2H5)2, or Lewis
bases, e.g., benzyltrimethylammonium hydroxide, or photo-
active catalysts, such as the aryl iodonium or sulfonium
salts described in U.S. Pat. No. 4~081,276, when the re-
action is carried out in situ. ~eneralized equations forsuch reactions in preparing the oligomer composition are
illustrated as follows:
~RH(-C~-~CH2)2 + Rs(H)y ~ ~ (C\2/CH-RH-fHCH2O-)~Rs (5)
O O
-- 26 --
-~ 1155~17
S(OH)2 ~ 3RR~c\ / H ) cat lvst~ H 1 2~H5-ocl~2 ~ RH (6)
Representative ether-forming condensation re-
actions are those between "E" and "S" precursors
` having active hydrogens with an N-(lower alkoxymethyl)
melamine as an "H" precursor, as i:llustrated by the fol-
lowing equations:
4RH(oCH3) + 2RC(OH)2 + RS(OH)~ + 2REOH ca 1~ t
~ R( ~H3) O~RcDRH(OCH3)-0~ Rs
(l+Y)RH(OCH3)y + YRC(OH)2 Y S( 2 E -CH30H
~C H(OCH3) O-Rs-O~RH (8)
The reactions are promoted with acid catalyst such as
p-toluene-sulfonic acid. Generally, temperatures from 60
to 120C for one to three hours or more can be used. The
use of reduced pressures to remove volatile lower alkanol
is also desirable.
Esterification reactions are illustrated by the fol-
lowing equations:
yRH(OH)2 + Base (e.g., pyridine) + Rs(OH)y -~ 2yCOC12 1
REOH
(ClOCO-RH-OOCO-)yRs HCl 3' (REOOCO-RH-OOCO-)yRs (9)
27
`` 11556177
yRs(OH)2 + 1
RH(OH) + y(C2H50)2CO ~ C2H50H + (C2H50C )y H
-- C 2H5-OH
Y(C2H50)2CO +
( HO-RS-OCO O- ) yRH
-- C 2H 50H
(C2H50COO-RS-OCOO~ Rl~ ~ (RE-OCOO-RS-OCOO-) RH ~10)
YF(H~OCI 2CH-&112) ~ ~ls(H)~ cataly~t ~
Y REC OOH
(CH2-&HCH2-RH-C~2~c~cH20 )y S Q
O 0~
(11)
(RE-coocH2lcHc~l2-RH-c~i2lcHcH2o )Y S
OH H
H2C\ /CH2)2 + 2RS(OH) catalyst
2R (:OOH + catalyst
(HO-R~-OCH2ClHcH20 )2RH -- 211 ~C
( RE-COO-RS-OCH2 ICHCH20 ~ ) 2RH (12 )
OH
-- 28 --
--' 115561~
Y H( OCH2C~-~CH2~2 + (l+~)R (OH) catalyst~
_ _ yR COOH
(HO-RS-OcH2cHcH2~-RH-)~OcH2lHcH2 R E
OH OH 2
[E-CO~O-Rs-OCH2CHCH20-RH-) -OCH2CHCH20~Rs (13)
i' Y
Such esterification reactions require the elimination of a
byproduct (water, hydrogen halide, or lower alcohol). Es-
terifications are promoted by heating the mixture at 50C
to 150C in the presence of a suitable catalyst, e.g.,
toluenesulfonic acid. The use of reduced pressures to
remove volatile byproduct is also desirable.
- 10 Physical properties, e.g., thermal dimensional
stability, of the crosslinked polymer resulting upon curing
of said oligomeric composition will be dependent on the
crosslink density of the polymer. An indication of that
crosslink density can be derived by calculating the molecular
weight per crosslink based on the monomeric precursor com-
ponents of the o]lgolneric composition. That calculation,
for example, in the case of Example 1, infra, is made by sub-
tracting the gram moles of the "S" precursor from the gram
moles of the "H" precursor, and dividing the difference into
the total ~eight in grams of the monomeric precursor compo-
nents in the oligomeric composition, the so-calculated
molecular weight per crosslink being 1241. Generally, the
calculated molecular weight per crosslink for the polymers
will be in the range of l!OO to 5000, preferably 1000 to 3000
the actual value generally being somewhat higher because of
side reactions, incomplete reactions, etc.
The oligomeric products resulting from the above-
illustrated equations (1) to (13) have predominantly the
1 1556i7
structures shown. The oligomeric product of equations (1),
(2), (5), (7~ (9~, and ~ are encompassed by generic
formula I; those of equations (3~, (4), (10), and (12) by
formula LVI; those of equations (6) and (8) by formula LV;
and that of equation (13~ by formula LVII. For example,
in the oligomeric product of equation (1), RE0-,
-CONH-RH-NHC0-, and -0-Rs-O- correspond respectively to "E",
"H", and "S" of formula I where ~ is 1. And in the oligomeric
product of equation ~2), which also falls within the scope
of formula I where ~ is also 1, RE0- corresponds to "E",
-CONH-RH-NHC0~0-RcOCONH-RH-NHCO~ corresponds to the "H"
bonded to "E", the -CONH-RH-NHC0- moiety bonded to -ORsO-
corresponds to the "H" bonded to "S", and -ORsO- corresponds
to "S" `
The oligomer products produced by these reactions
often will be highly viscous and thus difficult to cast in
the replication mold, and in addition may not be capable of
producing the necessary crosslink density in the subsequently
cured plastic article. Thus, it may be necessary to add to
the oligomer product a radiation addition-polymerizable mono-
or polyfunctional diluent monomer, e.g., 2-(N-butylcarbamyl)
ethylmethacrylate, to lower the viscosity of the casting
oligomeric composition and ensure the necessary crosslink
density in the plastic article made therefrom, that cross-
25 link density being manifested in a gel swell (determined intetrahydrofuran, as hereinafter described) within the range
of 35 to 20~ wt. %, preferably 80 to 150 wt. %. Generally
the amount of diluent monomer used should be less than 50
wt. % of the oligomeric composition (YiZ., oligomers plus
diluent monomer), since greater amounts will reduce the con-
30 -
- 115~617
centration of the "H" and ~'S" segments below that required to
provide the desired replicated plastic articles of this inven-
tion and will further increase the shrinkage during curing.
The oligomeric compositions (including the diluent
monomer where used~ and the articles made therefrom have the
same amount of "H" segments and the same amount of "S" seg-
ments (and consequently the same ratio of these moieties).
Said amount of "H'l generally will be an amount in the range
of 10 to 80 wt. % (of which amount at least 30 wt. % is due
to the carbocyclic and heterocyclic groups), "H" preferably
being 15 to 60 wt. %, and said amount of "S" will be an amount
in the range of 10 to 60 wt. %, preferably 15 to 45 wt. %, the
balance in the oligomeric composition being that attributable
to the functional moieties "E" and the diluent monomer from
which linking segments or moieties are derived as the balance
of the plastic articles. Those plastic articles preferably
have moduli over the temperature range of 23 to 120C which
fall on or within the boundary A-B-C-D of FIG. 1, which pro-
perty is measured by the procedure described in U.S. Pat. ;
3,853,595 where it is referred to as "storage shear modulus,
G~". The partlcular amounts of "H", "S" and "E" in the oli-
gomeric composition are such that the crosslinked polymer
derived therefrom preferably has such moduli. Said moduli
are dependent on the "H" and "S" contents and the crosslink
density of the plastic, said crosslink density being mani-
fested in gel swell as mentioned above. If a particular
oligomer composition has l'H", "S" and "E" contents falling
within their said ranges and yet the crosslinked polymer de-
rived therefrom has a dynamic shear moduli curve which falls
in whole or in part above the line A-Bof FIG.l, indicative of a
- 31 -
~, .
~ ,Ss
`-` 1155617
plastic which may be too rigid for a particular article
of this invention, the "H" content of the oligomeric com-
position will have to be lowered, e.g., by employing a
higher molecular weight "S" precursor or by eliminating or
decreasing the amount of chain extender in the preparation
of the oligomeric composition, or the crosslink density
will have to be lowered by using a higher molecular weight
"H" precursor or higher molecular weight "S" precursor. On
the other hand, if the dynamic shear moduli falls in whole
or part below the line D-C of FIG. 1, indicative of a plastic
which may be too flexible for a particular article of this
invention, the "H" content of the oligomeric composition
will have to be increased, e.g., by using a lower molecular
weight "S" precursor and/or employing a chain extender
together with additional "H" precursor,or the crosslink
density will have to be increased by using a lower molecular
wt. "H" precursor or "S" precursor or by employing a multi-
functional diluent monomer, e.g., 1,6-hexanediol diacrylate.
The proper particular amounts of "H" and "S" and crosslink
density for a particular system necessary to provide the
preferred dynamic shear moduli defined by A-B-C-D of
FIG. 1 can be readily arrived at empirically by varying
the above parameters as discussed above. These adjustments
of dynamic moduli are based on the generally linear
relationship, on a logarithmic basis, between dynamic
modulus (or tensile strength) and the amount of "H" in the
cured plastic.
The materials which can be used as "H", "S" and
"E" precursors in making the oligomeric compositions used
3o in this invention, as well as chain extending agents and
:, .
32
~, . .
~55617
catalysts used in their preparation and diluent monomers
and radiation or photo sensitizers and initiators incorporated
therein, are known materials, many o~ which are commercially
available. An illustrative description of those materials
follows below, reference being made to patents and the
literature for purposes of brevity.
Polysiloxane polyols useful as "S" precursors
include hydroxy-terminated diorgano-polysiloxanes in U.S. Pats.
4,098,742 and 3,886,865, and the siloxanes having a reactive
hydroxyl group bonded to at least 2 of its silicon atoms,
described in U. S. Pat. Nos. 3,577,264,3,976,676, and 4,013,698.
Particularly useful, commercially available
"S" percursors are silicone polycarbinols sold under the
trademark "DOW CORNING", such as Q4-3667.
Polyisocyanates, especially diisocyanates,
which can be used as "H" precursors, include those described in
U. S. Pat. No.s 3,641,199; 3,700,643; 3,819,586; 3,878,036;
3,931,117; 3,960,572; and 4,o65,587. Epoxides which can be
used as "H" precursors include diglycidyl ethers of bisphenol
A, diglycidyl isophthalate, diglycidyl phthalate, o-
glycidyl phenyl glycidyl ether, diglycidyl ethers of
resorcinol~ triglycidyl ethers of phloroglycinol, triglycidyl
ethers of methyl phloroglycinol, diglycidyl phenyl ether and
diglycidyl ether of hydrogenated bisphenol A, all of which
are described in Appendix 4-1 of "Handbook of Epoxy Resins",
by H. Lee and K. Neville, McGraw-Hill Book Company (1967).
Particularly useful commercially available
diisocyanates which can be used as "H" precursors include
isophorone diisocyanate sold under the trademark "IPDI"
by Veba-Chemie AG and methylene bis(4-cyclohexylisocyanate)
sold under the trademark "Hylene" WS by DuPont.
... . -- .
1 1~5617
"E" precursors which can be used include the
acrylyl compounds described in U.S. Pat. No. 3,700,643,
the hydroxy acrylates and methacrylates described in U.S.
Pat. No, 3,577,262 the ethylenically-unsaturated alcohols
described in U.S. Pat. No, 3,297,745, the hydroxyalkyl-
acrylates and methacrylates described in U.S. Pat. No,
4,065,587, the ethylenically unsaturated alcohols described
in U.S. Pat. No., 3,960,572 and the following epoxides:
butyl glycidyl ether, diglycidyl ether of propylene glycol,
diglycidyl ether of butanediol, vinylcycohexene dioxide,
mixed isomers of bis (2,3-epoxycyclopentyl)ether, bis(3,4-
epoxy-6-methylcyclohexylmethyl) adipate, bis(3,4-epoxy-
cyclopentyl~ether, 3,4-epoxy-6-methylcyclohexane carboxy-
; late, para-butylphenol glycidyl ether, limonene dioxide,
dicyclopentadiene dioxide and 3,4 epoxy-t-methylcyclo-
hexylmethyl-4-epoxy-6-methylcyclohexane carboxylate, all
of which epoxides are described by Lee and Nevill, supra.
Chain extenders which can be used in preparing
the oligomers used in this invention include the known
hydroxy-, carboxy-, amino or mercapto-terminated compounds
useful for that purpose (see U.S. Pat. No, 3,448,171.)
To promote oligomer-forming reactions, it is
generally desirable to utilize a catalyst. Typical examples
of such catalysts include compounds containing tertiary
amino groups, tln compounds and titanium compounds.
Examples of the preferred tin compounds are
dibutyltin dilaurate, dibutylin diethylhexoate, dibutyltin
sulfide, dibutyltin dibutoxide, stannous octoate, stannous
oleate and stannous chloride. Concentrations of catalyst
from about 0.01 to about 0.5 percent and preferably about
0.025 to 0.1 percent by weight of the total weight of
- 34 -
1--
,~ .
-`` 11~617
reactants(exclusive of solvents)can be used.
The diluting monomers are addition-polymerizable
monomers, viz., ethylenically unsaturated monomers and vic-
epoxy reactive diluents. The diluting monomers contribute
to the ~H", "S" or "E" content of the oligomeric composition
depending on the glass transition temperature, Tg, of a
homopolymer of the particular monomer. If the T of its
homopolymer is above about 350K, the monomer contributes to
the "H" content, below about 250K to the "S" content, and
between about 250K and 350C to the "E" content. The
concept of "hard" and "soft" monomers is well known (e.g., -
U.S. Pat. Nos. 4,077,926 and 4,077,932) and has been used
to described monomers to be optionally used in adhesive
compositions.
Suitable ethylenically unsaturated diluting
monomers and the glass transition temperature of their homo-
polymers are well known in polymer chemistry literature,
e.g., Brandrup and Immergut, Polymer Handbook, III - 61 to
73, Interscience Publishers (1967). Examples of the "hard"
monomers(and the Tg of their homopolymers) are isobornyl
acrylate (367K), methyl methacrylate (378K), cyclohexyl
chloroacrylate (372K), 2-chlorostyrene (392K), 2,4-
dichlorostyrene(406K), styrene (373K), acrylic acid (360K)
acrylamide, acrylonitile (393K) and methacrylonitrile
(393K). Examples of the "soft" monomers(and the Tg of
their homopolymers)are butyl acrylate (218K), ethyl
acrylate (249K), 2-ethylhexyl acrylate (223K), dodecyl
methacrylate (208K), and 4-decylstyrene (208K). Examples
of diluting monomers which contribute to neither the "hard"
- 35 -
1 1556 17
content nor to the "soft" content but become incorporated
into the linking segments (and the Tg of their homopolymers)
are 4~cyclohexyl-1-butene (318K~ dodecene (267K),
t-butyl acrylate (251K), cyclohexyl acrylate dodecyl
acrylate (270K), isopropyl acrylate (270K), methyl acry-
late (279K),butyl methacrylate (293K), 4-butoxystyrene
(320K), 2-(N-butylcarbamyl)ethyl methacrylate (304K) and
2-(N-ethylcarbamyl)ethyl methacrylate. Polyethylenically
unsaturated monomers also become incorporated into the
linking segments and are used in small quantities to reduce
the molecular weight of the cured oligomeric composition
per crosslink. Typical of such compounds are 1,4-butylene
~ dimethacrylate or acrylate, ethylene dimethacrylate or
: acrylate, trimethylolpropane di- or tri- acrylate, glyceryl
diacrylate or methacrylate, glyceryl triacrylate or methacy-
late, glycidyl acrylate or methacrylate, pentaerythritol
triacrylate or trimethacrylate, diallyl phthalate, 2,2-
bis(4-methacryloxyphenyl)-propane, diallyl adipate
di(2-acryloxyethyl)ether, dipentaerythritol pentaacrylate,
neopentylglycol triacrylate, polypropylene glycol diacrylate
or dimetilacrylate, and 1,3,5-tri-(2-methacryloxyethyl)-s-
triazine.
Diluting epoxy-reactive monomers include phenyl
glycidyl ether, 4-vinylcyclohexene dioxide, limonene dioxide,
4-vinyl-cyclohexene oxide, 1,2-cyclohexene oxide, glycidyl
acrylate, glycidyl methacrylate, and styrene oxide.
Suitable addition-polymerization catalysts for
use in the oligomeric compositions wherein the addition-
polymerizable group is an ethylenically unsaturated group
as represented in formula II, viz., acrylic or olefinic, are
- 36 -
~ ,i
1 155617
catalysts which liberate or generate a free-radical on
addition of energy. Such catalysts are well known and are
described frequently in polymerization art, e.g., Chapter
II of "Photochemistry" by Calvert and Pitts, John Wiley
& Sons (1966). Included among free-radical catalysts are
the conventional heat activated catalystssuch as organic per-
oxides and organic hydroperoxides; examples are benzoyl
peroxide, tertiary-butyl perbenzoate, cumene hydroperoxide,
azobis (isobutyronitrile) and the like. The preferred
catalysts are photopolymerization initiators which, when
used in an addition-polymerizable group-containing com-
position, facilitate polymerization when the composition
is irradiated. Included among such initiators are acyloin
and derivatives thereof, such as benzoin, benzoin methyl
ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin
isobutyl ether, and ~-methylbenzoin; diketones such as benzil
and diacetyl, etc.; organic sulfides such as diphenyl mono-
sulfide, diphenyl disulfide, decyl phenyl sulfide, and
tetramethylthiuram monosulfide; S-acyl dithiocarbamates,
such as S-benzoyl-N,N-dimethyldithiocarbamate; phenones such
as acetophenone, ~,~,a-tribromacetophenone, ~,~-diethoxy-
acetophenone, o-nitro-~ -tribromoacetophenone, benzo-
phenone, and p,p'-tetramethyldiaminobenzophenone; sulfonyl
halides such as p-toluenesulfonyl chloride, l-naphthalene-
sulfonyl chloride, 2-naphthalenesulfonyl chloride, 1,3-
benzenedisulfonyl chloride, 2,4-dinitrobenzenesulfonyl
bromide and p-acetamidobenzenesulfonyl chloride. Normally,
the initiator is used in amounts ranging from about 0.01 to
5% by weight of the total oligomeric composition. When
3 the quantity is less than 0.01% by weight, the photo-
- 37 -
1155617
polymerization rate becomes extremely low. If the
initiator is used in excess of 5% by weight, no corres-
pondingly improved effect can be expected. Thus, addi-
tion of such greater quantity is economically un~ustified.
Preferably, about 0.25 to 1.0% of initiator is used in
the oligomeric compositions.
For those oligomeric compositions in which the
radiation sensitive addition-polymerizable, functional
group-containing moiety is an epoxy group as represented in
formulas IIIorI~ any catalyst can be used which liberates or
generates a cationic polymerization catalyst upon exposure
to radiation. These catalysts are onium salts that are
well known in the art of polymerization, e.g., U.S. Pat.
No~ 3,826,650 in which it is taught that photosensitive
latent curing agents classified as aromatic diazonium salts
of a complex anion, e.g., hexafluoroantimonate, and the
like are used for photopolymerizing epoxy monomers, and
U.S. Pat. No, 4,081,276 in which it is taught that photo-
initiators capable of releasing a cationic polymerization
catalyst upon exposure to radiant energy are aromatic
halonium, aromatic Group Va onium, and aromatic Group VIa
onium salts of complex anions and are suitable for forming
an image on a substrate. The preferred catalyst for poly-
merizing the oligomeric compositions of the invention in
which addition-polymerizable functional group-containing
moiety is an epoxy group are aromatic iodonium or sulfonium
salts of complex anions selected from tetrafluoro borate,
hexafluorophosphate, hexachloroantimonate, hexafluoroanti-
monate. Examples of such salts include diphenyliodonium
- 38 -
.'' ~;:
1 1 S56 17
hexafluorophosphate, diphenyliodonium hexafluoroantimonate,
triphenylsulfonium hexafluorophosphate, and triphenyl
hexafluoroantimonate. Other preferred aromatic onium
salt photoinitiators are the aromatic iodonium and sul-
fonium salts of fluoroaliphatic sulfonic acid and the
bis(fluoroaliphaticsulfonyl)methanes that are disclosed
in U.S. Pat. No, 4,049,861.
- 39 -
.~ . .
~ L 5 5 ~ ~ ~
In making a particular shaped plastic article
of this invention for a specific application, economic
considerations will influence what particular oligomeric
composition or compositions and the mode of preparation
5. thereof should be used for that purpose. For example, in
making retroreflective cube corner sheeting for use as
highway traffic control markers where such requirements
as resistance to weathering and high impact strength are
essential, urethane-containing oligomeric compositions
preferably would be selected, such as those within the
scope of formulas I or LV, the urethane linkage imparting
stability to the sheeting upon its exposure to light, heat
and moisture, and the mode selected for making such oli-
gomeric composition advantageously being that of aforesaid
equation (2) because, for example, it involves only two
reaction steps and results in an oligomeric product with
a relatively high content of "H" segments, necessary for
satisfying the high impact strength requirement of the
sheeting, and because equation (2) permits the use of hydroxy-
acrylates, such as ?-hydroxyethylmethacrylate, and cycloali-
phatic polyisocyanates, such as isophorone diisocyanate,
these types of reactants being commercially available
raw materials which will augment that of the urethane
: linkage in providing the desired degree of weatherability.
As another example, in making flexible video
discs, where high abrasion resistance and optical trans-
parency are important, urethane-containing oligomeric com-
position preferably would be selected, such as those
-40 -
1 155617
falling within the scope of formulas I or LV, the urethane
linkage imparting abrasion resistance to the disc, and the
mode selected for making such oligomeric composition ad-
vantageously being that of aforesaid equation (1) because,
for example, of its limited number of reactions and its
amenability to use of reactants which are commercially
available and which impart to the disc requisite flexibility,
high optical transparency, and low haze; such reactants
are cycloaliphatic polyisocyanates,such as isophorone
diisocyanate, which also are commercially available and
which also impart to the oligomeric composition the property
of fast radiation curability.
As still another example, in making Fresnel lenses
where high optical transparency is important for image pro-
jection and high focusing efficiency is important for solarheat concentration, urethane-containing or aromatic car-
.. bonate-containing oligomeric compositions preferably would
be selected, such as those within the scope of formulas I
or LV, the urethane linkage imparting stability to light
and heat and the aromatic carbonate moiety imparting high
refractive index and concomittant low chromatic aberration,
and the mode selected for making said urethane-containing
oligomeric compositions advantageously being that of
equations (1) and (2) and the mode for making said carbonate-
containing oligomeric compositions advantageously being the
~: aforesaid equations (9) or (10), said equations (1)~ (2)
: (9) and (10) entailing a limited number of reactions and
- 41 -
1 ~55617
being amenable to use of commercially available materials
as reactants for imparting the requisite properties to the
plastic articles. In the case of pro~ection lenses and
solar collectors, said reactants can be isophorone diiso-
cyanate, polycaprolactone polyols, and hydroxyacrylates.
The shaped plastic articles of this invention
are typically prepared by pouring or filling a mold master
with the oligomeric composition, exposing the resulting
cast composition to actinic radiation to rapidly cure the
same, and removing from said mold master the resulting
shap,ed plastic article which comprises crosslinked plastic
and has a surface bearing microstructure replicated from
the mold master.
The particular mold master used in replication
will depend on the type of shaped article to be made. For
purposes of making optical lenses, e.g., ophthalmic lens
blanks, having a surface with an optical finish, the mold
master can be made of transparent (e.g., "Pyrex"~ glass,
such masters being commercially available. For purposes
of making diffraction gratings,e.g., spectral filters,
light collectors, and decorating decals, the mold master
can be made of metal with the diffraction pattern thereon
made by mechanical ruling or holographically, such dif-
fraction grating masters being commercially available,
e.g., see the "Diffraction Grating Catalog" (1974), of
PTR Optics Corp., Waltham, Mass., and Bulletins ACA
1004-1-1270 and ACA 1006-1-1-270 of Angenieux Corp. of
America, Oceanside, N.Y.
*Trade Mark
- ~2 -
~1~
1 ~ 5561~
For cube-corner sheeting, linear Fresnel lenses,
and other shaped plastic articles having raised or indented
microstructure-bearing surfaces, mold masters can be used
which are made of plastic, e.g., acrylonitrile-butadiene-
styrene, or preferably (~for mass production of such repli-
cated articles) made of metal fabricated directly from a
suitable metal by engraving, hobbing, assembling as a bundle
a plurality of metal parts machined in the desired configu-
ration, or other mechanical means or by electroforming,
e.g., see "Encyclopedia of Polymer Science & Technology",
Vol. 8, p. 651 (1968), and "Principles of Electroplating
and Electroforming", W. Blum and G. B. Hogaboom, 3rd Ed.
McGraw-Hill Co., Inc., Chap. VIII (1949), and U.S. Pat. No.
3,689,346.
Where the microstructure to be replicated can be
initially formed by machining originals made of plastics
- which are difficult to wet, such as commercially available
acrylic resins, e.g, that sold under the trademark "LUCITE",
electroformed metal mold masters can be formed from such
machined originals and used to make shaped plastic articles
~uch as the diffraction gratings, Fresnel lenses and
retroreflective sheeting described in the working examples
of this specification) by treating the machined plastic
surface to render it wettable and sensitized (for example,
by the treatment described in U.S. Pat. No. 3,666,527),
rendering the surface conductive by simultaneous contact,
- ~3 -
~'
,
1 155617
using a two-nozzle spray gun, with an ammonical silver
salt solution, and a reducing agent, such as formaldehyde
or dextrose, plating or electroforming nickel on the
silver-coated surface from a commercially available
nickel bath, and separating the resulting metal layer
from the plastic original, thus generating a metal mas-
ter which can be used for replicating said shaped plas-
tic articles or ~rom which second and third generation
electroformed nickel copies can be made as required to
provide a tooling supply for replicating said shaped
plastic articles. Where the microstructure to be repli-
cated can not be initially machined on a plastic original
for purposes of making masters used in replicating such
articles as the video disc described hereinafter in a
working example of this specification, mold masters
fabricated by photoresist techniques can be used, e.g.,
see the journal articles in "Science", Vol. 196, No.
4293, p. 945 (1977~, and "Optics and Laser Technology"
August, 1977, p. 169.
The cast, curable oligomeric composition can
be cured by exposure to actinic radiation, viZ., ionizing
or non-ionizing radiation, a curing technique well-known
- ~4 -
:
` 1155617
and widely-used in the art of radiation addition polymeri-
zation (e.g., see U.S.Pat. No. 3,700,643). Typically,
ultravlolet radiation produced by such sources as mercury
arcs, sunlamps, or xenon lamps, with UV radiation primarily
in the regions of about 2000 to 4000A,will be most useful.
Ionizing radiation produced by electron accelerators, e.g.,
continuous filament or swept beam accelerators, can be
used, wherein the electrons are provided with the kinetic
energy derived from acceleration through a field varying
from 150 kilovolts up to as high as 4000 kilovolts. Useful
radiation dosage required to complete the curing will vary,
depending on the particular oligomeric composition used,
its molecular weight and the crosslinking density desired;
for ultraviolet radiation, a useful dosage will generally
be in the range of 0.1 to 100 ~oules per square centimeter
exposed and for ionizing radiation, such as electron beam,
; a useful dosage will be 5 x 103 rads to 107 rads. Normally
the exposure is carried out at or near room temperature
and atmospheric pressure. An inert atmosphere, such as
nitrogen or carbon dioxide gases, may be desired in curing
some oligomeric compositions, viz., those relying on free-
radical curing mechanisms, e.g., acrylate-, or methacrylate-
terminated oligomers. Radiation processing equipment use-
ful in the practice of this invention is commercially
available, e.g., untraviolet lamp systems sold by Radiation -
Polymer Corp., Plainfield, Illinois, and Fusion Systems
Corp., Greenbelt, Maryland, and ionizing radiation systems
sold by Energy Sciences, Inc., Burlington, Mass. and
Radiation Dynamics, Inc., Long Island, N.Y. (Although the
3o radiation used in curing the oligomeric composition has
- 45 -
.
.,
1 ~55617
been described in detail herein as being actinic radiation,
thermal radiation can be used, e.g., 50 to 150C for 5 min to
several hours depending on the oligomeric composition and
catalyst used; thermal radiation is not preferred because
it is more time-consuming~ requires more energy, and is not
; as controllable as actinic radiation).
Following radiation of the cast composition (ac-
tinic radi~tion effects complete curing in 1/2 to 5
seconds generally), the cured, shaped plastic article is
readily separated or removed from the mold master. Mold
release agents may be used, though generally they are not
: required. Depending on the particular shaped plastic
article made and the nature of the mold master, the mold
master can be repeatedly used for replication done on a
continuous mass production basis.
In selecting an oligomeric composition for use
in preparing a particular shaped article, it has been
found useful to prepare a transmissive diffraction grating
test ~ample from the composition. Such sample can be used
to measure replicating fidelity capability of the oligomeric
composition and the thermal dimensional stability capa-
bility of the oligomeric composition. ~IG. 2 schemati-
cally illustrates a replicated diffraction grating useful
as a test sample, the preparation and testing of which is
described hereinafter. The test measures the first order
diffraction efficiency of both the master grating and
replicated test sample, the efficiency of which is related
to the depth of the grooves. A comparison of the effi-
ciency of the replicated test sample to that of the master
- ~6 -
- ,-
. .
.
11556~7
grating determines the fidelity of replications. Generally
the oligomeric composition of this invention will give dif-
fraction grating test samples having a replicated efficiency
of at least 85% of that of the master grating. ~or some
particular shaped articles, the replication efficiency must
be significantly greater than 85% (for example, for repli-
cated video discs, the replication efficiency must approach
at least 99%) and for such articles an oligomeric composi-
tion must be selected which will produce a diffraction grat-
ing test sample having such replication efficiency. Repli-
cation efficiency will be dependent on the degree of shrink-
age of the diffraction grating test sample; the greater the
shrinkage, the lower the replication fidelity. Shrinkage in
turn is dependent on the number of double bonds present in
the oligomeric composition per unit weight thereof, and gen-
erally the greater such number of double bonds, the greater
the degree of shrinkage. For acrylate- or methacrylate-ter-
minated oligomers, the shrinkage will be about 20 cc/gram moleof double bonds, and this shrinkage factor can be used as a
guide in selecting an oligomeric composition necessary to
yield the desired replication efficiency.
Generally, the oligomeric compositions will yield
diffraction grating test samples which have high thermal di-
mentional stability. For example, generally when said test
samples are heated in air in a programmed manner from 23 to
170C, the first order diffraction efficiency is practically
constant over these temperatures. (By contrast, the first
order diffraction efficiency of comparative diffraction grat-
ing test samples made of poly(methyl methacrylate), polyvinyl
chloride, cellulose acetate butyrate, and polyethylene tere-
phthAlate dropped rapidly or precipitously to zero when the
` - 47 -
,. ,, ~ .
115561~
temperature reached about 70 to 115C). The change in first
order diffraction efficiency of diffraction grating test
samples of the oligomeric compositions of this invention
upon heating at 130C in air for 1 hour is less than 15%,
as compared to the first order diffraction efficiency before
heating. Generally, the higher the weight ratio of "H" to
"S" in the oligomeric composition~ and the lower the mole-
cular weight between crosslinks in the shaped article pro-
duced therefrom, the greater the thermal dimensional sta-
bility~ i.e., the smaller the change in first order diffrac-
tion efficiency upon heating.
Some of the shaped articles of this invention will
require higher thermal dimensional stability than others,
viz., a change in first order diffraction efficiency on
heating at 130 of less than 5%. For example, replicated
cube-corner sheeting, the use of which exposes it to elevated
temperatures, e.g., on a road sign heated by the sun in
Arizona, will require a high thermal dimensional stability,
whereas a replicated video disc, played at room temperature,
will not require high thermal dimensional stability.
- 48 -
.;
j .,~ ....
1~55617
In addition to the preparation of diffraction
grating test samples, it has been found useful to prepare
cured, self-supporting film samples (with planar surfaces)
of the oligomeric composition and measure the tensile
strength, elastic modulus, elongation-to-break, and dyna-
mic shear moduli of the film samples, the preparation and
testing of which is described elsewhere herein. The
values of these measurements will be factors to consider
in selecting an oligomer composition for fabrication of a
particular shaped plastic article therefrom. For example,
a replicated video disc which may have to be relatively
limp (or "floppy") for playing on a particular type of
player, would be prepared from oligomeric compositions
which yield test film samples having relatively low elas-
tic modulus and dynamic shear moduli and relatively highelongation. In contrast,a rigid or stiff replicated Fresnel
lens, used for projection of images, would be prepared
from Gligomeric compositionswhich yield test film samples
having relatively high elastic modulus and dynamic shear
moduli, and relatively low elongation. The test film
samples can also be measured for optical properties as an
aid in selection of an oligomeric composition for prepara-
tion of replicated shaped plastic articles used for optical
purposes, e~g., where it is necessary to satisfy require-
ments of high transmission (i.e., at least 90%) and lowhaze ti.e., less than 5%, preferably less than 2%).
FIGS. 3 and 4 schematically illustrate a portion
of a typical replicated cube-corner retroreflective sheet
1 made in accordance with this invention. The geometry
or configuration of this type of article is described,
- 49 -
B
- 1155617
for example, in U.S. Pat. No. 3,810,804. Reference 2
generally designates one of the minute cube corner elements
or formations disposed in an array on one side of the
sheeting 1. Each element 2 has the shape of a trihedral
prism with three exposed planar faces, substantially
perpendicular to one another, with the apex of the prism
vertically aligned with the center of the base. The angle
between the faces is tne same for each cube-corner element
in the array, and will be about 90. Said angle can
slightly deviate from 90 by design, i.e., the angle will
be dependent upon the particular application of the sheeting,
as is well-known. For example, in the United States, state
governments generally specify maximum brightness of retro-
reflective traffic control markers at from 0.2 to 2
divergence (or observational) angles, thus dictating a spe-
cific angle between the faces of the cube-corner elements
in the marker. The cube corner elements 2 in sheet 1 are
all of the same dimensions and are aligned in an array
or pattern of rows and columns,the bases being in the same
plane,and adjacent elements being contiguous at the edges
of their bases such that there is no spacing or flat areas
between adjacent elements. The cube-corner elements 2
surmount a body portion 3, the lower surface of which is
smooth or planar, the body portion being preferably inte-
gral with elements, the sheeting thus being monolithic.Generally, each cube-corner element 2 has a side edge
dimension up to 0.025 inch (0.635 mm~ preferably less
than 0.010 inch (0.254 mm). The body portion 3 is suffi-
ciently thick to render the sheeting self-supporting and
3o tough so as to maintain the integrity of the array of
- 50 -
r~
. ~,
1155617
cube-corner elements 2. Generally, the body portion will
be 0.002 to 0.030 inch (.05 to .075 mm), preferably 0.003
to 0.010 inch (0.075 to 0.25 mm).
In the application of such cube-corner sheeting
as a highway traffic control marker, it will be desirable
to seal air spaces between the faces of the cube-corner
elements with a sealing film placed over the top of the
elements, e.g., in the manner described in U.S. Pat. No.
4,025,159, and coat the exposed surface of the film with
a pressure-sensitive adhesive composition which is dried
and adhered to a rigid sheet, e.g., aluminum, which forms
a base for the resulting marker. The exposed lower surface 8
of the body portion 3 of the cube-corner sheeting 1 may
be first selectively coated with transparent ink layers
to provide the desired traffic control message, e.g., "STOP",
and then coated with a top coat to protect the message,
e.g., against weathering.
The principle of operation of retroreflective
cube corner structures is well known, e.g., see J. Optical
Society of America, Vol. 48, No. 7, July, 1958, p. 496.
That principle is in essence illustrated by FIG. 5.
Referring to that figure, in which a single cube corner
element 2 is shown schematically with two of its faces 6, 7
being substantially perpendicular to one another, as shown
~ 25 by the angle 90 + ~, and the body portion 3 having an
~ exposed lower surface 8. An incident ray of light I
enters the element 2 upon striking surface 8 in a direction
perpendicular thereto, passes through the body portion 3,
strikes face 6, is reflected to the other faces, is
3o reflected from the latter and passes out of the element
.
- ~155617
as reflected ray I'. Perfect retroreflection of incident
ray I for the particular element shown in ~IG. 5 would
result in the reflected ray passing out the element in a
path, shown by the broken line, exactly parallel to the
path of the incident ray. The deviation between the path
of perfect reflection and the actual path, I', is shown
by the divergence angle ~, which will be 0.2 to 2
in the case where state governments specify the same as
described above. In order to obtain and maintain the
desired specified divergence angles, the desired dimensions
and angles of the cube-corner elements must be obtained
and maintained within very narrow limits. For example,
as described by J. Optical Society of America, supra,
for a plastic having an index of refraction of 1.5 (typical
for the plastics comprising the shaped articles of this in-
vention, said plastics generally having an index of 1.48 to
1.6), the divergence angle ~ can be expressed by the equa-
tion ~ = 4.9 ~ and thus when ~ is 0.2, ~ is 0.041 or 6.8
minutes of arc, which is an exceedingly small angle. If
the angles between the faces of a replicated cube-corner
element cannot be controlled and maintained, e.g., because
of shrinkage, distortion upon removal from the mold, or of
thermal distortion, the efficiency of retroreflection will
be affected. Even a slight lack of control and maintenance
f the angle can significantly adversely affect the effi-
ciency. Rigid, high elastic modulus plastics, such as poly
(methyl methacrylate), have thus been resorted to in the
art, however, such plastics are brittle and have low heat
; distortion resistance. In contrast, the desired angles of
the plastic cube corner elements made in accordance with
_ 52 -
....
''''''''I " . ~
1 1 5~6~ 7
this invention are controlled and maintained even at ele-
vated temperatures, and the elements are flexible, articles
with such elements being of wide application, e.g., where
high impact strength is desired or required, as in the case
of highway "STOP" sign. Additionally, the retroreflective
cube-corner sheeting of this invention can be made with
initial high brightness capability, e.g., at least 600
candles/lumen at 0.2~ divergence angle.
FIG. 4A illustrates the combination of the repli-
cated cube-corner retroreflective sheet 1 of FIGS. 3,4 with
a retroreflective beaded sheet 14, this type of construction
being described in U.S. Pat. No, 4,025,159, as a combination
cube-corner exposed-lens product of the general type de-
scribed in U.S. Pat. No. 3,140,340. Sheet 14 comprises a
layer 15 of binder material, a monolayer of transparent
glass microspheres 16 partially embedded in the binder ma-
terial, and specular reflective material 17 underlying and
in optical connection with the embedded surface of the micro-
spheres. The points of contact between the apices of cube-
corner elements 2 and microspheres 16 can be bonded asshown in FIG. 4A and as taught in U.S. Pat. No. 4,025,159,
forming hermetically sealed cells or pockets 18, or the
sheets 1 and 14 can be spaced apart as taught in U.S. Pat.
No. 3,140,340, forming an air gap which provides a prism-air
interface. In this construction,light rays escaping from
the cube-corner sheet 1 are reflected back from beaded sheet
14, thereby providing wide angularity and divergence of re-
troreflection.
Other articles of this invention are echelon or
Fresnel lenses, such as those with configurations described
.. ". ~ .,
1155617
in U.S. Pat. Nos. 3,334,958, 3,972,593, 3,511,563, and
4,082,433, and used, for example, in overhead projectors.
FIG. 6 illustrates a plurality of one type of such lens 9,
viz., linear Fresnel lenses (fabricated in accordance with
this invention, as shown herebelow) in the form of a
continuous sheet 10 of contiguous replicated plastic
lenses, which sheet can be cut to separate the individual
lenses. The flexibility and dimensional stability of the
Fresnel lens made in accordance with this invention makes
them useful in a wide field of application, such as
decorative mouldings, e.g., automobile moulding, described
in ~.S. Pat. No. 3,908,o56.
As mentioned hereinbefore, replicated shaped
plastic articles can be fabricated in accordance with
this invention for purposes of information processing
and transmission. FIGS. 7 and 8 illustrate an example of
such articles, namely a video disc 11 (the fabrication of
which is exemplified hereinafter) having spirally arranged
tracks 12 each of which is made up of circumferentially-
; 20 spaced, minute depressions or holes commonly called
"micropits", with lengths, for example, about 1.2 ~m,
widths about 0.75 ~m, and depths about 0.3 ~m, and which
are circumferentially spaced, for example 1.5 ~m, the
variations of said lengths and spacings depending on
the frequency of the carrier signals which are re-
corded on the disc, articles of this type being described
in Optics & Laser Technology, supra. (Alternatively, the
information on the video disc can be in spiral grooves
with the video information appearing on the bottom and
wall regions of the grooves in the form of geometric or
~ - 54 -
~',
1 155617
topographical variations, as described, for example, in
U.S. Pat. Nos. 3,795,534 and 3,882,214.) The high repli-
cation fidelity capability of this invention is particularly
well-suited to fabrication of the above-described
replicated video discs.
Objects and advantages of this invention are
illustrated in the following examples thereof. In these
examples, the parts referred to are parts by weight and
the percents referred to are percents by weight. In all
runs in which the addition polymerizable oligomer products
were synthesized, a dry air atmosphere was maintained
during the course of reaction. The cured film test samples
used for measuring physical properties were made by
mixing 100 parts of the oligomer product (or oligomer
15 product diluted with diluent monomer) with 0.5 part 2,2-
diethoxyacetophenone photoinitiator, vacuum degassing the
resulting mixture to remove entrapped air, and casting
the mixture to a thickness of 250 microns (using a flat-
bed knife coater) between two sheets of 125_micron thick
polyethylene terephthalate polyester, thereby forming a
"sandwich" assembly. Using a laboratory ultraviolet
processor (viz., a "QC Processor", manufactured by
Radiation Polymer Corp.), the "sandwich" assembly was
passed six times on a moving belt conveyor moving at
15 m per minute under a bank of two medium pressure mercury
vapor arc lamps operating at 80 watts/cm of length. The
conveyor was spaced at a distance of 10 cm from the lamps.
At the completion of the curing process, the cast mixture
cured to a solid film of crosslinked polymer between the
~ 55
1 1~5617
.
polyester sheets, which were then stripped from the polymer
film and physical properties of the film were then tested.
The replicated diffraction grating test sam-
ples (used for measuring replicated fidelity and thermal
dimensional stability) were made in the following examples
by using a high frequency holographic metal mold diffrac-
tion grating master, having 867.7 line pairs per milli-
meter. This master was coated (by a flat-bed knife coater)
with a 375-micron thick layer of the oligomer product (or
10 oligomer product diluted with diluent monomer), to which 0.5
percent 2,2-diethoxyacetophenone had been added. A poly-
ethylene terephthalate polyester film (125-micron thick)
was placed as a cover sheet over the layer of curable
oligomer material and the resulting construction was cured
with said "QC Processor" by placing it on a conveyor
moving at 15 metersper minute under two medium pressure
mercury vapor lamps operating at 80 watts per cm of length.
A distance between the lamps and the oligomer surface of
10 cm was maintained. After six passes under the lamps,
polymerization of the oligomer product was complete. The
polyester cover sheet was stripped off and the layer of
polymerized product (a replicated diffraction grating) was
separated from the master and used as a test sample. The
first order diffraction efficiency of the test sample
was measured by the procedure described by Beesley et al
in J. Applied Optics, Vol. 9, No. 12, Dec. 1970, p. 2720,
and the diffraction efficiency of the test sample was cal-
culated. The test sample was then placed in a forced air
circulating oven at 130C for one hour. After this heat
- 56 -
c~;
1~55617
treatment, the first order diffraction efficiency was again
measured and the percent difference from the original value
was taken as the measure of the resistance of the test sam-
ple to thermal distortion.
The diffracting grating test samples were also
used to determine the gel swell of the crosslinked polymers
as an indication of the degree of crosslinking thereof (al-
though the gel swell of the cured film samples could also
have been used for this purpose). The gel swell was deter-
mined by immersing a sample portion of known weight, Wl
(about 0.5 g), of the diffraction grating test sample in
25 ml tetrahydrofuran solvent (analytical reagent grade)
for 24 hours at about 23C, removing the resulting swelled
sample portion, wiping or padded off the adhering film of
solvent from the sample portion and quickly determining its
weight, W2. The used solvent was evaporated to dryness and
the weight, W3, of the dried residue (the solubilized frac-
tion of the sample portion) was determined. The weight
percent gel swell of the tested crosslinked polymer was
calculated by the formula:
% gel swell = 2 ~ W3 X 100
Wl
The lower the percent gel swell, the greater the degree of
crosslinking (see "Encyclopedia of Polymer Technology",
Vol. 4, p. 63-65, published by Interscience Pub. (1966)).
`'; .
,
115561~
EXAMPLE I
Into a l-liter metal reactor, equipped with a
propeller agitator, therm meter, addition funnel, and dry air
sparger extending into the reactor through the lid thereof,
were charged 200 g (0.083 mole) poly(dimethylsiloxane)triol
silicone fluid ("Dow Corning" Q4-3557), 210 g (1.60 moles)
2-hydroxyethyl methacrylate, and 0.3 g of dibutyltin dilaurate.
The mixture was heated to 65C and 220 g (0.99 mole) iso-
phorone diisocyanate (IPDI") was added over a two-hour
period. The reaction was complete in 16 hours as determined
by infrared analysis for isocyanate. The resulting acrylate-
capped polysiloxane urethane oligomer product had a structure
essentially that of formula XXI. Eighty parts of the oligomer
product was diluted with 20 parts 2-(N-butylcarb myl)ethyl
methacrylate diluent monomer and the diluted oligomer product
was cured to form film and diffraction grating test samples,
; the properties of which are set forth in TABLE III.
EXAMPLE 2
Into a l-liter reactor, equipped as described
in Example 1, was charged 157 g (o.60 mole) methylenebis-
(4-cyclohexylisocyanate) ("Hylene~' WS). Then, while
stirring, there were added, over a period on one hour,
a mixture of 288 g (0.12 mole) poly(dimethylsiloxane)diol
silicone fluid ("Dow Corning" Q4-3667) and 1.83 g
( 3 mole) 2-aminoethanol chain-extender, and the
temperature of the resulting mixture was allowed to
rise to 70C. The reaction was allowed to proceed for
an additional hour at which time 131 g (1.00 mole)
2-hydroxyethyl methacrylate was added to the resulting
isocyanate-terminated, chain-extended, urea-urethane
prepolymer product. The mixture was held at 70C and
the reaction was complete in 12 hours as determinèd by
infrared analysis, whereupon 24~ g (1.08 moles) 2-(N-
butylcarbamyl)ethyl methacrylate diluent monomer was
*Trade Mark
. - 58 -
1155~ ~
added. Infrared analysis verified that the resulting
acrylate-capped, chain-extended, polycaprolactone urea-
urethane oligomer product (excluding the diluent monomer)
had essentially the structure of formula XXXIII. Cured
film and diffraction grating test samples were pre-
pared and their compositions and properties are set
.,
forth in TABLE III
:.
_XAMPLE 3
Into a 1-liter reaction vessel, equipped as
10 in Example 1, were charged 120 g (o.46 mole) methylenebis-
(4-cyclohexylisocyanate) ("Hylene~'WS) and 0.25 g of
; dibytyltin dilaurate, and the mixture heated to 65-70C
while stirring. There was then added over a period of
one hour a mixture of 219 g (0.091 mole) poly(dimethyl-
15 siloxane)diol silicone fluid ("Dow Corning" Q4-3667)
and 46 g (0.023 mole) poly(oxypropylene) diamine
("Jeffamine" D-2000) and the resulting mixture heated
with stirring for an additional hour at 70C. To the
stirring mixture containing the resulting isocyanate-
terminated, polysiloxane-polyether, urea-urethane pre-
polymer product was added 131 g (1 mole) 2-hydroxyethyl
methacrylate and the resulting mixture was heated for
three hours whereupon it was found by infrared analysis
that all the isocyanate therein had disappeared. As
verified by infrared analysis, the resulting acrylate-
capped, polysiloxane-polyether, urea-urethane oligomer
product had essentially the structure of formula XXXII.
*Trade Mark
- 59 -
cir~
J`'r,~
1 15.~6~ 7
Films and diffraction grating test samples
were prepared using 70 parts o~ the above oligomer pro-
duct diluted with 30 parts 2-(N-butylcarbamyl)ethyl
methacrylate, the compositions and properties of these
articles being set forth in TABLE III.
.~
EXAMPLE 4
-
~ In a 4-liter reactor, equipped as in Example 1,
{ a mixture of 15.1 g (0.13 mole) 1,6-hexamethylenediamine
r
and 1250 g (0.52 mole) poly(dimethylsiloxane)diol
; 10 silicone fluid ("Dow Corning" Q4-3667) was added during
a one-hour period to a mixture of 572 g (2.58 mole)
isophorone diisocyanate ("IPDI") and 2 g of dibutyltin
dilaurate while maintaining the temperature of the
reactor contents at 65-70C. The mixture was heated
at this temperature for an additional two hours to obtain
the isocyanate-terminated polysiloxane, urea-urethane
, prepolymer product, and 536 g (2.76 moles) 2-hydroxyethyl
methacrylate was then added over a one hour period. The
resulting mixture was allowed to react at 65-70C until
the disappearance of isocyanate, as determined by infrared
analysis, was observed, the period of reaction so re-
quired being 48 hours. Infrared analysis verified that
the resulting acrylate-capped, polyester, urea-urethane
oligomer product had essentially the structure of formula
XXIV. The mixture was cooled, 593 g (2.57 moles)
2-N-butylcarbamyl)ethyl methacrylate diluent monomer was
added, and film and diffraction grating test samples
were prepared from the diluted oligomer product, the
compositions and properties of these articles being set
forth in TABLE III.
--~0--
,,
~' !, . . .
1 ~ 55~ ~ 7
r~ N~ CO ~
r~ rl ~r1r1lr) CO ~_
1 0 ~ I .~
rl ~) 11
.1~ ~ rl ~
o~ h u~ g C~ cO r-l y
P I ~ r r r~ r~ O
E-
.~
b~
~> l~o ~ S Il~ ~ r
~ ~ O +~ . . . I
~rl ~ ~ a) \~ 1~1 0 0 r~
C) ~) ~ tH
~ ~ ~ O
h ~S~ r CO CJ~ ~ CO
o+~ td u\ u~
~ r ~ C`J ~ ~ ~d
rl ~d a~
~4 ~a \ brl r~
~h rl ~ (rl 1~ cO u~
r~0 ~ ~ ~ ) U" (Yi S-~
1~ ~ C~J C~J CU C~J C)
~d
~1 ~ ~
~ ~ U~
H u2 $ ~ I co co
H O O
IYl 1 ~
~ ~ o o~ ~ ~ co ~ ~
u2rl ~ C\lu~
Fl l
rl ~d O O
h ,~ t~ U~
~) r~l .rl ~J 0~ bD
1~ rl ~ rl E3 O O O O ~ S I
h ~ ) O~
r1 ~ ~ ~3 O O
~ ~ cd ~
.rl IL) ~CU
cq q-l rl bl) ~ ~ r~ l
~> O .rl ~: CJ ~ \D r~ ~
P~ ~ h ~ C~Jrl rl rl rl rl
E~ ~ ~
rd ~
,~ ~ -bD a~ ~
~J ~ ~ h
rl u~ .rl ~ (S~ ~ rl
~ ~r3 ~ ~ ~ C~ CO Is ~
o r~ ~) ~r ~ ~ ~ rl rl
~-rl U~ ~I h
;rl tH _ . C~l ~f)co
O P:: 1--O~ ~D O~ O O
_(\I r-l rl rl h h
O ~ O\ O r-l Cl ~)
C~ O _ . . . . U7 U~
~ u~ c~,l tr)~r)~`J 1~
115~17
Various modifications and alterations of this
invention will become apparent to those skilled in the art
without departing from the scope and spirlt of thls 1nvention.
. . .
Z
- 62 -
