U.S. patent number RE31,533 [Application Number 06/446,635] was granted by the patent office on 1984-03-06 for information carrying discs.
This patent grant is currently assigned to Minnesota Mining and Manufacturing Company. Invention is credited to Terry W. Lewis.
United States Patent |
RE31,533 |
Lewis |
March 6, 1984 |
Information carrying discs
Abstract
Information-carrying discs are comprised of a substrate having
an information bearing layer derived from 15 to 100% by weight of
at least one polyacryloyl-containing heterocyclic monomer.
Inventors: |
Lewis; Terry W. (Woodbury,
MN) |
Assignee: |
Minnesota Mining and Manufacturing
Company (Saint Paul, MN)
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Family
ID: |
26815324 |
Appl.
No.: |
06/446,635 |
Filed: |
December 3, 1982 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
117466 |
Feb 1, 1980 |
04296158 |
Oct 20, 1981 |
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Current U.S.
Class: |
428/65.1;
360/135; 369/275.1; 369/276; 428/162; 428/163; 428/847.8; 525/908;
526/262; 526/263; 544/314; 548/317.5; 548/319.5 |
Current CPC
Class: |
G11B
3/70 (20130101); G11B 3/705 (20130101); G11B
23/0057 (20130101); Y10T 428/24529 (20150115); Y10T
428/24537 (20150115) |
Current International
Class: |
G11B
3/00 (20060101); G11B 23/00 (20060101); G11B
3/70 (20060101); B32B 003/02 () |
Field of
Search: |
;428/65,162,163 ;360/135
;427/54.1 ;525/908 ;526/262,263 ;544/314 ;548/307,312 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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859711 |
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0000 |
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BE |
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2519476 |
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Dec 1977 |
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DE |
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Primary Examiner: Page; Thurman K.
Attorney, Agent or Firm: Sell; Donald M. Smith; James A.
Litman; Mark A.
Claims
I claim:
1. An information-carrying element comprising a substrate having
adhered to at least one surface thereof a separate layer having a
maximum thickness of from 1.0 to 100 .mu.m and a circular or spiral
pattern of grooves with or without modulations, depressions,
protuberances, said separate layer comprising a polymer layer
derived from 15 to 100% by weight of at least one
polyacryloyl-containing heterocyclic wherein said heterocyclic is
selected from the formulae:
wherein A.sup.1 and A.sup.2 independently are alkoxyalkyl groups
having terminal ethylenic unsaturation and having the formula
##STR11## wherein R--O-- is a monovalent residue of an aliphatic
terminally unsaturated primary alcohol, ROH, formed by the removal
of the active hydrogen from the primary --OH group, R having the
formula:
wherein E is ##STR12## .Iadd.b is zero or an integer of from 1 to
6, .Iaddend. c is an integer of from 1 to 6,
R.sup.1 and R.sup.4 are independently selected from hydrogen and
methyl,
R.sup.5 is an aliphatic group having from 1 to 15 carbon atoms, and
no more than two catenary oxygen or carboxy groups, a valence of
m+1.
m is an integer of from 1 to 5,
R.sup.2 is selected from hydrogen and groups of the formula
##STR13## wherein R.sup.6 is selected from alkyl and alkenyl
groups
R.sup.7 is an aliphatic or aromatic group of up to eight carbon
atoms,
R.sup.3 is an alkylene group of from 1 to 6 carbon atoms with up to
one catenary oxygen atom, and
Z is a heterocyclic group of the formula ##STR14## wherein X is a
divalent group which is required to complete a 5- or 6-membered
heterocyclic ring, or ##STR15## wherein R.sup.12 and R.sup.13
independently represent hydrogen or methyl,
R.sup.14 represents hydrogen, an alkyl group, or a phenyl
group,
R.sup.13 and R.sup.14 together may represent trimethylene or
tetramethylene group,
m represents a number of from 1 to 30,
n is 2 or 3, and
A represents a group of the formula ##STR16## wherein X.sup.1
represents the divalent radical necessary to complete a 5- or
6-membered heterocyclic ring group.[., said process comprising
exposing said composition to radiation while the composition is in
the presence of an atmosphere of at least 2% by volume of oxygen to
polymerize said components having formula (1) or (2).]..
2. The element of claim 1 wherein said polymer layer was derived
from 30 to 100% by weight of at least one polyacryoyl containing
heterocyclic.
3. The element of claim 1 wherein said heterocyclic is selected
from formula (2), m is 1 to 4, and X.sup.1 is selected from
##STR17## wherein R.sup.15, R.sup.16, R.sup.17 and R.sup.18
independently represent hydrogen, an alkyl group, and alkylene
group, a cycloalkyl group, or a phenyl group, and
R.sup.19 represents hydrogen, an aliphatic group, or an aromatic
group.
4. The element of claim 3 wherein R.sup.15, R.sup.16, R.sup.17 and
R.sup.18 are selected from hydrogen, alkyl of 1 to 4 carbon atoms,
alkylene or 1 to 4 carbon atoms, or phenyl, and X.sup.1 is selected
from ##STR18##
5. The element of claim 1 wherein said heterocyclic is selected
from formula (1) and X is selected from: ##STR19## wherein R.sup.8,
R.sup.9, R.sup.10, and R.sup.11 are independently hydrogen, alkyl
group of 1 to 4 carbon atoms, cycloalkyl group of 3 to 6 carbon
atoms, and phenyl group of 6 to 12 carbon atoms, and
A.sup.3 is an alkoxyalkyl group as defined for A.sup.1 and
A.sup.2.
6. The element of claim 5 wherein ##STR20## and R.sup.8 and R.sup.9
are hydrogen or alkyl of 1 to 4 carbon atoms and R.sup.2 is
hydrogen.
7. The element of claim 6 wherein ##STR21## and R.sup.5 is alkylene
of 1 to 15 carbon atoms.
8. The element of claim 1 wherein said polymer layer is further
derived from 70 to 10% by weight of acrylates copolymerizable with
said plyacryloyl containing heterocyclic.
9. The element of claim 6 wherein said polymer layer is further
derived from 70 to 10% by weight of acrylates copolymerizable with
said polyacryloyl containing heterocyclic.
10. The elements of .[.claims.]. .Iadd.claim .Iaddend.3.[., 4, 5,
6, 7, 8, or 9.]. in which said information carrying element
comprises a disc having a circular pattern of grooves with
information-carrying deformities in the form of modulations,
depressions or protuberances wherein the depth or height of the
information-carrying deformities from the mean height of the
surface is between 0.03 and 2 .mu.m and said separate layer is
between 1 and 25 .mu.m in its maximum thickness. .Iadd. 11. The
elements of claim 4 in which said information carrying element
comprises a disc having a circular pattern of grooves with
information-carrying deformities in the form of modulations,
depressions or protuberances wherein the depth or height of the
information-carrying deformities from the mean height of the
surface is between 0.03 and 2 .mu.m and said separate layer is
between 1 and 25 .mu.m in its maximum thickness. .Iaddend..Iadd.
12. The elements of claim 5 in which said information carrying
element comprises a disc having a circular pattern of grooves with
information-carrying deformities in the form of modulations,
depressions or protuberances wherein the depth or height of the
information-carrying deformities from the mean height of the
surface is between 0.03 and 2 .mu.m and said separate layer is
between 1 and 25 .mu.m in its maximum thickness. .Iaddend..Iadd.
13. The elements of claim 6 in which said information carrying
element comprises a disc having a circular pattern of grooves with
information-carrying deformities in the form of modulations,
depressions or protuberances wherein the depth or height of the
information-carrying deformities from the mean height of the
surface is between 0.03 and 2 .mu.m and said separate layer is
between 1 and 25 .mu.m in its maximum thickness. .Iaddend..Iadd.
14. The elements of claim 7 in which said information carrying
element comprises a disc having a circular pattern of grooves with
information-carrying deformities in the form of modulations,
depressions or protuberances wherein the depth or height of the
information-carrying deformities from the mean height of the
surface is between 0.03 and 2 .mu.m and said separate layer is
between 1 and 25 .mu.m in its maximum thickness. .Iaddend. .Iadd.
15. The elements of claim 8 in which said information carrying
element comprises a disc having a circular pattern of grooves with
information-carrying deformities in the form of modulations,
depressions or protuberances wherein the depth or height of the
surface is between 0.03 and 2 .mu.m and said separate layer is
between 1 and 25 .mu.m in its maximum thickness. .Iaddend..Iadd.
16. The elements of claim 9 in which said information carrying
element comprises a disc having a circular pattern of grooves with
information-carrying deformities in the form of modulations,
depressions or protuberances wherein the depth or height of the
surface is between 0.03 and 2 .mu.m and said separate layer is
between 1 and 25 .mu.m in its maximum thickness. .Iaddend.
Description
FIELD OF THE INVENTION
The present invention relates to information carrying systems and
more particularly to discs which carry light readable or stylus
readable information. These discs may be useful in carrying
information which is convertible to electronic signals for such
varied uses as sound recordings, audio/visual recordings, or even
computer type information retrieval.
BACKGROUND OF THE INVENTION
Information retrieval in the form of discs having information
distributed in a circular or spiral pattern has been available in
various forms for many years. Early forms of musical reproduction
equipment, for example, used discs with either holes or
protuberances to pluck an array of strings or vibrating posts to
produce music. Early displays of moving pictures operated by
rotation of a disc bearing consecutive images on the periphery. The
most common form of storing reproductions of musical performances,
which has been in use for about one hundred years, is the
phonograph record which uses a spiral pattern of grooves having
vertical and horizontal modulations to generate signals which can
be converted to sound.
With the introduction of the laser to industry, a new information
storage system was developed which comprised a disc having circular
or spiral patterns of depressions or protuberances which would
disturb, reflect, or refract incident light patterns. These
information storing discs, often used for storage of audio/visual
information and generally referred to as video discs, are well
known in the art. Such U.S. Pat. Nos. as 3,658,954 (Apr. 25, 1972);
3,795,534 (Mar. 5, 1974); 3,798,134 (Mar. 19, 1974); 3,855,426
(Dec. 17, 1974); 3,901,994 (Aug. 26, 1975); 4,124,672 (Nov. 7,
1978); 4,126,716 (Nov. 21, 1978); and 4,130,620 (Dec. 19, 1978)
shown various constructions, compositions, and processes for
forming video discs.
In addition to the laser readable video disc, another commercial
construction is used which is more similar to the classic
phonograph recording. This type of construction, as described in
RCA Review, Vol. 39, No. 1, March 1978, comprises a spiral array of
grooves which is tracked by a stylus. The grooves are impressed
with coded information in the form of vertical and/or radial
modulations.
Even though these systems are read by totally different techniques,
they are affected by similar, if not identical, problems.
Imperfections in the depressions, protuberances, or modulations
cause undesirable or spurious signals to be transmitted. The
imperfections can be produced during manufacture of the disc or can
develop from wear during use or manipulation of the disc.
The present invention relates to information storage discs for use
with laser or stylus readout systems which have good fidelity and
resistance to wear.
SUMMARY OF THE INVENTION
It has been found according to the present invention that
information storage devices comprising disc blanks or discs having
a circular or spiral pattern of depressions, protuberances and/or
grooves, with or without modulations, can be constructed from a
substrate having as the information carrying layer on at least one
surface thereof a layer formed from a composition comprised of from
15-100% by weight of a polyacryloyl containing heterocyclic
compound. At least 15% by weight is needed for curing in the
presence of oxygen and at least 30% by weight is needed for
abrasion resistance. These heterocyclic compounds are the subject
matter of commonly assigned U.S. Pat. Nos. 3,821,098 and 3,808,226
and U.S. patent application Ser. Nos. 51,876 (filed June 25, 1979)
now U.S. Pat. No. 4,249,011, 51,877 (filed June 25, 1979) and
51,888 (filed June 25, 1979).
DETAILED DESCRIPTION OF THE INVENTION
The polyacryloyl containing heterocyclics are defined according to
the present invention as materials described by the formulae:
wherein A.sup.1 and A.sup.2 independently are alkoxyalkyl groups
having terminal ethylenic unsaturation and having the formula
##STR1## wherein R--O-- is a monovalent residue of an aliphatic
terminally unsaturated primary alcohol, ROH, formed by the removal
of the active hydrogen from the primary --OH group, R having the
formula:
wherein
E is ##STR2## c is an integer of from 1 to 6, b is zero or an
integer of from 1 to 6,
R.sup.1 and R.sup.4 are independently selected from hydrogen and
methyl,
R.sup.5 is an aliphatic group having from 1 to 15 carbon atoms, and
no more than two non-adjacent catenary oxygen or carboxy groups, a
valence of M+1,
m is an integer of from 1 to 5,
R.sup.2 is selected from hydrogen and groups of the formula
##STR3## wherein R.sup.6 is selected from alkyl and alkenyl
groups
R.sup.7 is an aliphatic or aromatic group of up to eight carbon
atoms,
R.sup.3 is an alkylene group of from 1 to 6 carbon atoms with up to
one catenary oxygen atom, and
z is a heterocyclic group of the formula ##STR4## wherein x is a
divalent group which is required to complete a 5- or 6-membered
heterocyclic ring, or ##STR5## wherein R.sup.12 and R.sup.13
independently represent hydrogen or methyl,
R.sup.14 represents hydrogen, an alkyl group, or a phenyl
group,
R.sup.13 and R.sup.14 together may represent a trimethylene or
tetramethylene group,
m represents a number of from 1 to 30,
n is 2 or 3, and
A represents a group of the formula ##STR6## wherein X.sup.1
represents the divalent radical necessary to complete a 5- or 6-
membered heterocyclic ring group. The preferred classes of these
materials are (a) from formula (1):
wherein X is selected from ##STR7## wherein R.sup.8, R.sup.9,
R.sup.10 and R.sup.11 are independently hydrogen, alkyl group of 1
to 4 carbon atoms, cycloalkyl group of 3 to 6 carbon atoms, and
aryl group (e.g., phenyl group) of 6 to 12 carbon atoms, and
A.sup.3 is an alkoxyalkyl group a defined for A.sup.1 and A.sup.2,
and (b) from formula (2):
wherein m is from 1 to 4, and X.sup.1 is selected from ##STR8##
wherein R.sup.15, R.sup.16, R.sup.17 and R.sup.18 independently
represent hydrogen, an alkyl group, an alkylene group, a cycloalkyl
group, or a phenyl group, and
R.sup.19 represents hydrogen, an aliphatic group, or an aromatic
group.
It is more preferred, with regard to the preferred compounds of
formula (1) that R.sup.2 be hydrogen, that X be ##STR9## and
R.sup.8 and R.sup.9 be hydrogen or alkyl of 1 to 4 carbon atoms,
that m be 2 to 5, that R be [(CH.sub.2).sub.b ].sub.m R.sup.5
(CH.sub.2).sub.c, that R.sup.5 be alkylene of 1 to 15 carbon atoms,
and/or that R.sup.4 be hydrogen. It is more preferred with regard
to formula (2) that X.sup.1 be selected from ##STR10## and that
R.sup.15, R.sup.16, R.sup.17, and R.sup.18 be independently
selected from hydrogen, alkyl of 1 to 4 carbon atoms, alkylene of 1
to 4 carbon atoms and phenyl. Most preferably R.sup.15 -R.sup.18
are selected from hydrogen and alkyl of 1 to 4 carbon atoms.
As noted above, the information bearing layer of the disc blanks or
discs of the present invention must be formed from a polymeric
resin derived from a composition comprising at least 15% by weight
of the polyacryloyl heterocyclics. The heterocyclics may of course
constitute 100% by weight of reactive or polymeric components in
the resin. The compositions used in the process of the present
invention may be diluted with up to 85% by weight of any
ethylenically unsaturated monomer. Preferably the majority of
comonomers are at least diethylenically unsaturated monomers.
Generic classes include the acrylates, methacrylates, acrylic
anhydrides, ethylenically unsaturated anhydrides, olefinic
compounds, acrylamides, ethylenically unsaturated amides and
urethanes, vinyl esters, vinyl ethers, vinyl halides, vinyl epoxy
resins, vinyl silanes and siloxanes, vinyl heterocyclics, and
prepolymers and polymers of these materials. Particularly suitable
ethylenically unsaturated monomers include methyl methacrylate,
ethyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate,
styrene, butadiene, 2-chlorostyrene, 2,4-dichlorostyrene, acrylic
acid, acrylamide, acrylonitriles, t-butyl acrylate, methyl
acrylate, butyl acrylate, N-vinyl pyrrolidone,
2-(N-butylcarbamyl)ethyl methacrylate and 2-(N-butyl-carbamyl)ethyl
methacrylate, and 2-(N-ethylcarbamyl)ethyl methacrylate. Preferably
35 to 80% and most preferably 45 to 60% by weight of
copolymerizable components comprise the heterocyclic agents of the
present invention. Other diluting monomers that can be incorporated
into the composition of the invention include 1,4-butylene
dimethacrylate or acrylate, ethylene dimethacrylate, hexamethylene
diacrylate (hexanediol diacrylate) or dimethacrylate, glyceryl
diacrylate or methacrylate, glyceryl triacrylate or
trimethacrylate, pentaerythritol triacrylate or trimethacrylate,
pentaerythritol tetraacrylate or tetramethacrylate, diallyl
phthalate, dipentaerythritol pentaacrylate, neopentylglycol
triacrylate and 1,3,5-tri(2-methacryloxyethyl)-s-triazine.
The compositions should also contain polymerization or free radical
initiators in order to provide more photosensitivity to the system
to speed up the cure. Polymerization initiators suitable for use in
the compositions of the invention are compounds which liberate or
generate a free-radical on addition of energy. Such initiators
include peroxy, azo, and redox systems each of which are well known
and are described frequently in polymerization art, e.g. Chapter II
of Photochemistry, by Calvert and Pitts, John Wiley and Sons
(1966). Included among free-radical catalysts are the conventional
heat activated catalysts such as organic peroxides and organic
hydroperoxides; examples are benzoyl peroxide, tertiarybutyl
perbenzoate, cumene hydroperoxide, azo-bis(isobutyronitrile) and
the like. The preferred initiators are photopolymerization
initiators which 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
.alpha.-methylbenzoin; diketones such as benzil and diacetyl, etc.;
organic sulfides such as diphenyl monosulfide, diphenyl disulfide,
decyl phenyl sulfide, and tetramethylthiuram monosulfide; S-acyl
dithiocarbamates, such as S-benzoyl-N,N-dimethyldithiocarbamate;
phenones such as acetophenone,
.alpha.,.alpha.,.alpha.-tribromoacetophenone,
.alpha.,.alpha.-diethoxyacetophenone,
2,2-dimethoxy-2-phenylacetophenone, o-nitro-.alpha.,.alpha.,
60-tribomacetophenone benzophenone, and
p,p'-tetramethyldiaminobenzophenone; aromatic iodonium and aromatic
sulfonium salts; sulfonyl halides such as p-toluenesulfonyl
chloride, 1-nahthalenesulfonyl chloride, 2-naphthalenesulfonyl
chloride, 1,3-benzenedisulfonyl chloride,
2,4-dinitrobenzenesulfonyl bromide and p-acetamido-benzenesulfonyl
chloride. Normally the initiator is used in amounts ranging from
about 0.01 to 5% by weight of the total polymerizable composition.
When the quantity is less than 0.01% by weight, the polymerization
rate becomes extremely low. If the initiator is used in excess of
5% by weight, no correspondingly improved effect can be
expected.
Other additives may be usefully included in the compositions and
resins used in the practice of the present invention. Conventional
materials such as antioxidants, lubricants, surface active agents,
antistatic agents, flow control aids, dyes, pigments, etc. may be
useful ingredients depending upon the ultimate use of the disc
blank or disc.
The structure of the information carrying discs of the present
invention comprises a substrate having the information impressed or
blank groove impressed polyacryloyl containing heterocyclic coating
layer on at least one side thereof. The substrate may be
substantially any solid material, including but not limited to
polymeric materials such as polyesters, polycarbonates,
polyacrylates, polyurethanes, polyvinyl resins, polyesters,
polyamides, and polysiloxanes; ceramic or glass materials; fibrous
materials; metals; etc. The backing may be transparent or opaque
depending upon the readout system used. If the backing is opaque to
the curing radiation, a stamper which is substantially transparent
to the curing radiation must be used. Primer layers may be used
between the substrate and the information carrying layer, but this
is not essential, depending upon the adhesion of the polymer to the
substrate. The substrate may be of any thickness, but is usually
from 50 to 5000 .mu.m. The information carrying layer is critical
in its dimensions and must be between 1 and 25 .mu.m for a video
disc and up to 100 .mu.m for an audio disc in its maximum
thickness. The term maximum thickness is used, because the layer,
having depressions, protuberances, or grooves thereon, varies in
thickness. This limit therefore applies to the maximum thickness of
the layer.
The information is encoded on the information carrying layer as
depressions, protuberances, and/or grooves with or without arc-like
(e.g., semicircular, hyperbolic, etc.) modulations in either a
circular, or spiral pattern on the layer. The depth or height of
the information carrying deformity from the plane of the surface or
the mean height of the surface is normally between 0.03 to 5 .mu.m.
In laser readout systems, this dimension is usually between 0.03
and 2 .mu.m, preferably between 0.05 and 0.8 .mu.m, and more
preferably between 0.07 and 0.5 .mu.m. In stylus readout systems,
this dimension is usually between 0.05 and 5 .mu.m, preferably
between 0.08 and 2 .mu.m, and more preferably between 0.10 and 1.0
.mu.m. For an LP record, this dimension is preferably between 25
and 75 .mu.m. The width (peak to peak) between grooves in audio
systems is about 60-80 .mu.m.
The light read systems may have a metallized coating over the
information carrying surface and another polymer layer, preferably
of an abrasion resistant material, over the metal layer, if a
reflective rather than transmissive readout system is being used.
These coatings can be laid by a variety of manners including vapor
deposition or reduction of metal salt solutions.
Alternatively, two reflectivity metallized discs may be adhesively
secured together so that the two information bearing surfaces are
sandwiched in the middle of the composite and information is then
read reflectively through a transparent substrate.
Capacitively read discs may have a metallized coating applied to
the replicated information bearing surface to provide electrical
conductivity. The metallized coating may then be provided with an
electrically insulative overlayer.
Replicas to be read with a stylus may also use a lubricant or
lubricating layer on the information bearing surface to minimize
stylus wear.
Preferably the information is encoded into the information carrying
layer in a spiral pattern rather than a circular pattern so that
the reading element can follow a single path rather than having to
shift from one concentric circle to another.
If the information carrying layer is to be penetrated by light
during readout, it must be transmissive of the reading radiation.
Ordinarily a fairly narrow band of radiation is used to read the
discs so that information carrying layer may have to be
transmissive of at least 50% of the radiation in a 100 nm, 50 nm,
or even 30 nm band. Preferably the layer is transmissive of at
least 75 to 90% of the radiation within such a band.
One other important aspect of the present invention is that the low
applied pressures and low temperatures associated with the use of
liquid compositions allows for the use of non-metallic stampers and
masters.
These and other aspects of the present invention will be shown in
the following examples.
EXAMPLE 1
A resin composition was prepared by mixing 60 gms of
1,3-bis{3-[2,2,2-(triacryloyloxymethyl)ethoxy]-2-hydroxypropyl}-5,5-dimeth
yl-2,4-imidazolidinedione (hereinafter referred to as Compound A)
containing about 25% by weight of pentaerythritol tetraacrylate, 40
gms of 1,6-hexanediol diacrylate and 2 gms of
2,2-dimethoxy-2-phenyl-acetophenone. This composition was mixed by
shaking and then filtered through a 5 .mu.m filter. The resulting
photopolymerizable material was used to make a video disc with a
nickel video disc stamper.
Approximately 2.0 cm.sup.3 of this photopolymerizable liquid
material was spread by a cylindrical coating roller between a
nickel video disc stamper and a primed 0.18 mm polyester film. The
sheet of polyester film was positioned between the roller and the
stamper to serve as the base substrate. The rolling process spread
out a bubble free coating of photopolymerizable resin over the
surface of the stamper and simultaneously covered it with the
polyester sheet. The stamper covered in this manner was then passed
several times at 3 cm/sec under a 200 watt/inch high intensity,
medium pressure Hg vapor lamp. The ultraviolet radiation exposure
cured the photopolymerizable liquid, hardening it and bonding it to
the primed polyester film. After the exposure, the laminated
structure containing the replicated information was easily peeled
from the nickel stamper. The sheet was then cut to produce a
circular center hole and a circular outside shape, both concentric
with the replicated information tracks. The resulting video disc
replica had an information bearing layer 10.+-.5 .mu.m thick. The
disc lay flat when placed on a level surface. It provided a good
television picture when played on a video disc player.
EXAMPLE 2
A video recording was made in a comercially available polymeric
photoresist layer and the layer developed by standard
wash-development techniques after exposure to light. The recording
was then vapor coated with 10 nm of chrome. The resulting
photoresist master was used in place of a nickel stamper to make a
video disc replica according to the procedures of example 1. This
replica was capable of producing a good television picture when
played on a video disc player and was also useful as a stamper for
repeated replications.
EXAMPLE 3
A resin composition was prepared by mixing 70 gm of Compound A with
30 gm of hexanediol diacrylate and 2 gm of the photoinitiator of
Example 1. The resulting material was used to make a video disc
according to the procedure of Example 1. The video disc replica
made in this way had a cured information bearing layer 6.+-.2 .mu.m
thick. This disc lay flat when placed on a level surface. It
provided a good television picture when played on a video disc
player.
EXAMPLE 4
A resin composition was prepared by mixing 30 gm of Compound A with
70 gm of hexanediol diacrylate and 2 gm of the photoinitiator of
Example 1. The resulting material was used to make a video disc
according to the procedure of Example 1. The video disc replica
made in this way had a cured information bearing layer 5.+-.2.5
.mu.m thick. This disc lay flat when placed on a level surface. It
provided a good television picture when played on a video disc
player.
EXAMPLE 5
A sample of commercially available polyvinylchloride film 14 inches
square was prepared for use as a video disc substrate in the
following way. The sheet was placed between two flat, smooth,
chrome-steel plates. The plates were in turn sandwiched between
four layers of cardboard and the resulting stack pressed for ten
minutes in a hydraulic press. The press was operated with a force
of 11 metric tons, and the press platens were heated to 160.degree.
C. This pressing operation reduced the surface roughness of the
manufactured film and provided a substrate of suitable
flatness.
The substrate thus prepared was used to make a video disc replica
according to the procedure of Example 1, except that the surface of
the polyvinylchloride opposite the information bearing layer was
also coated with the resin composition. The cured polymer showed
good adhesion to the otherwise untreated surface of the
polyvinylchloride substrate. The disc lay flat when placed on a
level surface and provided a good television picture when played on
a video disc player. Information was read from this disc with the
laser beam incident from either side of the disc.
EXAMPLE 6
A sheet of cast acrylic material (polymethylmethacrylate) 1000
.mu.m thick was sputter etched according to the following procedure
to promote adhesion of the polymer. The acrylic substrate was
placed in a Vecco Model 776 radio frequency diode sputtering
apparatus operating at a frequency of 13.56 MHz. The substrate was
then subjected to a radio frequency sputter etch as described in
assignee's copending application Ser. No. 80,530, filed Oct. 10,
1979.
The resin composition of Example 1 and the roll coating technique
of Example 1 was used to prepare a video disc replica with the
above described substrate. The semi-flexible substrate was allowed
to bend slightly when it was lowered slowly onto the stamper as the
roller moved along. The resin composition was cured with a bank of
low intensity UV lamps, and the replica removed from the stamper.
An aluminum coating 30 nm thick was vapor coated onto the surface
of the information bearing layer. A circular hole was cut in the
center of the disc, and a circular outer edge was cut. The
resulting disc was then played on a video disc player; a good
television picture was obtained. The laser beam of the player was
incident through the uncoated acrylic surface and reflected by the
aluminum coating on the information bearing surface.
EXAMPLE 7
An audio record replica was prepared using commercially available 1
mm polyvinylchloride as the base element. The resin composition of
Example 1 was used within the roll-coating technique of Example 1.
The semi-flexible base element was allowed to bend slightly as it
was lowered slowly on to the audio record stamper as roller moved
along. The resin composition was cured to 75 .mu.m maximum
thickness by several passes at 3 cm/sec. under a 200 watt/inch high
intensity, medium pressure Hg vapor lamp. The replica was then
stripped from the stamper. A circular hole was cut in the center of
the record and a circular outer edge was cut. The resulting replica
was successfully played on a conventional stereo audio system.
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