U.S. patent application number 10/988937 was filed with the patent office on 2005-04-28 for tissue paper used for heat-sensitive stencil sheet, heat-sensitive stencil sheet, and method of making the same.
Invention is credited to Yamaguchi, Hideyuki.
Application Number | 20050089703 10/988937 |
Document ID | / |
Family ID | 27345990 |
Filed Date | 2005-04-28 |
United States Patent
Application |
20050089703 |
Kind Code |
A1 |
Yamaguchi, Hideyuki |
April 28, 2005 |
Tissue paper used for heat-sensitive stencil sheet, heat-sensitive
stencil sheet, and method of making the same
Abstract
A tissue paper used for heat sensitive stencil sheet to be used
for a heat-sensitive stencil sheet comprising natural fibers,
synthetic fibers, or their mixture, while being impregnated with an
ionizing radiation curable type of resin, and a heat-sensitive
stencil sheet having a thermoplastic resin film being bonded
thereto, wherein, at surface of one side of the resin film, there
is provided the tissue paper used for heat-sensitive stencil sheet,
which is that being bonded the thermoplastic resin film by
point-bonding with using an ionizing radiation-curable resin, and
there is provided an anti-sticking layer on the other side of the
thermoplastic resin film.
Inventors: |
Yamaguchi, Hideyuki;
(Numazu-shi, JP) |
Correspondence
Address: |
COOPER & DUNHAM, LLP
1185 AVENUE OF THE AMERICAS
NEW YORK
NY
10036
|
Family ID: |
27345990 |
Appl. No.: |
10/988937 |
Filed: |
November 15, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10988937 |
Nov 15, 2004 |
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10077455 |
Feb 14, 2002 |
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6866924 |
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Current U.S.
Class: |
428/537.5 |
Current CPC
Class: |
Y10T 428/249959
20150401; Y10T 428/249953 20150401; Y10T 428/24826 20150115; D21H
27/30 20130101; Y10T 428/249924 20150401; B41N 1/243 20130101; B41N
1/241 20130101; Y10T 428/24802 20150115; Y10T 428/31993 20150401;
D21H 25/06 20130101 |
Class at
Publication: |
428/537.5 |
International
Class: |
B32B 029/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 14, 2001 |
JP |
P2001-037652 |
Jan 31, 2002 |
JP |
P2002-024816 |
Feb 13, 2002 |
JP |
P2002-035712 |
Claims
1. A tissue paper used for heat-sensitive stencil sheet comprising
natural fibers, synthetic fibers, or their mixture, wherein the
tissue paper used for heat sensitive stencil sheet is being
impregnated with an ionizing radiation-curable resin.
2. A multi-layer paper consisting of two or more layers of tissue
papers for heat-sensitive stencil sheet, in which the each tissue
paper are combined on other, so that they are in a mode separable
to one other for separated utilizing thereof, and the multi-layer
paper is being impregnated with an ionizing radiation-curable type
of resin.
3. A tissue paper use for heat-sensitive stencil sheet according to
claim 1 or a multi-layer paper according to claim 2, wherein the
tissue paper or the multi-layer paper is being impregnated with an
ionizing radiation-curable resin by size-press processing.
4. A tissue paper used for heat-sensitive stencil sheet impregnated
with the ionizing radiation-curable resin, wherein the tissue paper
used for heat-sensitive stencil sheet is being obtained by
separation of a multi-layer paper according to claim 2.
5. A tissue paper used for heat-sensitive stencil sheet, wherein
the tissue paper used for heat-sensitive stencil sheet is being
obtained by irradiating a tissue paper used for heat-sensitive
stencil sheet according to any one claim selected from a group
consisting claim 1, claim 3 and claim 4 to an electron beam.
6. A heat-sensitive stencil sheet, in which there are provided a
thermoplastic resin film, the thermoplastic film being, at surface
of one side thereof, bonded by point-bonding (spot-bonding) to a
tissue paper used for heat-sensitive stencil sheet according to any
one claim selected from a group consisting claim 1, claim 3, claim
4 and claim 5, and an anti sticking layer on the other surface of
the thermoplastic resin film.
7-9. (canceled).
10. A tissue paper used for a heat-sensitive stencil sheet
according to claim 1, wherein the tissue paper is irradiated with
an electron beam.
11. A tissue paper used for a heat-sensitive stencil sheet
according to claim 3, wherein the tissue paper is irradiated with
an electron beam.
12. A tissue paper used for a heat-sensitive stencil sheet
according to claim 3, wherein the multi-layer paper is irradiated
with an electron beam.
13. A tissue paper used for a heat-sensitive stencil sheet
according to claim 4, wherein the tissue paper is irradiated with
an electron beam.
14. A tissue paper used for a heat-sensitive stencil sheet
according to claim 1, further comprising a thermoplastic resin
film, bonded at a surface of one side thereof to the tissue paper
in a manner of point bonding (spot bonding), and an anti-sticking
layer on another surface of the thermoplastic resin film.
15. A tissue paper used for a heat-sensitive stencil sheet
according to claim 3, further comprising a thermoplastic resin
film, bonded at a surface of one side thereof to the tissue paper
in a manner of point bonding (spot bonding), and an anti-sticking
layer on another surface of the thermoplastic resin film.
16. A tissue paper used for a heat-sensitive stencil sheet
according to claim 11, further comprising a thermoplastic resin
film, bonded at a surface of one side thereof to the tissue paper
in a manner of point bonding (spot bonding), and an anti-sticking
layer on another surface of the thermoplastic resin film.
17. A tissue paper used for a heat-sensitive stencil sheet
according to claim 4, further comprising a thermoplastic resin
film, bonded at a surface of one side thereof to the tissue paper
in a manner of point bonding (spot bonding), and an anti-sticking
layer on another surface of the thermoplastic resin film.
18. A tissue paper used for a heat-sensitive stencil sheet
according to claim 13, further comprising a thermoplastic resin
film, bonded at a surface of one side thereof to the tissue paper
in a manner of point bonding (spot bonding), and an anti-sticking
layer on another surface of the thermoplastic resin film.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a tissue paper used for
heat-sensitive stencil sheet, a heat-sensitive stencil sheet, and a
method of fabricating the same. More specifically, the present
invention relates to a high quality of heat-sensitive stencil sheet
to be perforated with irradiation of infrared light or flash light
from a halogen lamp, a xenon lamp, or a flash bulb, pulsed
irradiation of laser light, or heat irradiation from a thermal
head, and a method of fabricating the same at less cost.
[0003] 2. Description of the Related Art
[0004] There are generally known heat-sensitive stencil sheets, in
which tissue papers used are (1) a paper as called Japanese paper
which is milled from a natural fiber such as mulberry, mitsumata,
or Manila hemp (as disclosed in Japanese Examined Patent
Publication of Tokkou Shou 41-7623, (2) a paper milled from a
synthetic fiber such as rayon, vinylon, polyester, or nylon, (3) a
mixture milled paper of the natural fiber (1) and the synthetic
fiber (2) (as disclosed in Japanese Examined Patent Publication of
Tokkou Shou 49-18728, and (4) a tissue paper called polyester paper
which is made by a polyester fiber or a mixture of it and
non-oriented polyester fiber as a fibrous binder, and formed by the
use of heat rolls, as disclosed in Japanese Examined Patent
Publication of Tokkou Shou 49-8809.
[0005] A these tissue papers are deflected in shape or changed in
dimensions by moisture or temperature thus declined in their
properties, the improvements were proposed that include an effort
for minimizing the dimensional change in the humid conditions, as
disclosed in Japanese Unexamined Patent Publication of Tokkai Shou
1-254396 and Japanese Examined Patent Publication of Tokkou Shou
06-43151, or a use of a synthetic resin impregnated in tissue to
act as an adhesive for bonding between the tissue and a film, as
disclosed in Japanese Examined Patent Publication of Tokkou Shou
55-47997. Also, methods of fabricating polyester paper having an
improved dimensional stability and the resistance to heat are
proposed as disclosed in Japanese Unexamined Patent Publication of
Tokkai Shou 68-76597 and Japanese Unexamined Patent Publication of
Tokkai Shou 58-76598.
[0006] Moreover, proposed are a method of fabricating a
heat-sensitive stencil sheet impregnated with a resin of ionizing
radiation-curable type, in which, a thermoplastic resin film and a
tissue paper used for heat-sensitive stencil sheet are bonded each
other by an resin of the ionizing radiation-curable resin, as
disclosed in Re-publication by Japanese Language of PCT Application
of Kokusaihyou Hei 1-801872, or a method of fabricating a
heat-sensitive stencil sheet which comprises steps of bonding and
laminating a thermoplastic resin film and a tissue paper together
with an alcohol solution of an ionizing radiation-curable type of
polymer or oligomer and, after drying, exposing a resultant
combined web to ultraviolet ray or electron beam for reinforcement,
as disclosed in Japanese Unexamined Patent Publication of Tokkai
Hei 01-154796.
[0007] However, the foregoing conventional methods do not yet
satisfy the primary requirements for any heat-sensitive stencil
sheet such as; (1) an excellent passing-through of printing ink,
(2) the ease of perforation, (3) no releasing of the fibers, (4)
the resistance to printing action, and (5) the high
productivity.
[0008] The conventional tissue papers for heat-sensitive stencil
sheet, the heat-sensitive stencil sheets, and their fabricating
methods have the following drawbacks.
[0009] As common, the conventional tissue papers for heat-sensitive
stencil sheet including natural fibers are impregnated with a resin
material by a known manner for preventing a change in dimensions
thereof, which is caused by absorbing to and removing from of the
moisture the natural fibers, and liberating of the fibers from
tissue papers. Accordingly, the tissue paper may easily be deformed
by a stress applied during bonding of it with the thermoplastic
resin film, and after that, if it is released from its stressed
state, it springs back to its original dimensions, in spate of
having been bonded with the thermoplastic resin film, thereby it
will cause a degrading in the surface smoothness of the
thermoplastic resin film, and it will hence be found difficult to
control the laminating action.
[0010] Although conventional tissue paper used for heat-sensitive
stencil sheet made of a synthetic fiber material is subjected to
heat-sensitive process for increasing the bonding strength between
the fibers, it may be increased in the density while having no
removal of the fibers, hence declining the passing-through of
printing ink. On the contrary, if the tissue paper is pressed down
at a lower temperature, though it is improved in passing-through of
ink. It may have the fibers removal. For compensating these
problems, the conventional tissue paper used for heat-sensitive
stencil sheet can favorably be reinforced with a rein material,
however, as the synthetic fibers are lower than the natural fibers
in the physical strength, the above described disadvantage will
more be emphasized with the synthetic fiber contained in tissue
paper.
[0011] There is known method for producing a heat-sensitive stencil
sheet supported by a tissue paper as a supporting substrate, which
comprises steps of placing the two kinds of material layers in
integrated form of plastic resin and tissue paper, then
impregnating them at once with resinous solution to make
impregnated them with resin, drying and exposing to ionizing
radiation ray or electron beam for building with each other allows
the combined web being favorably controlled. By this method, the
controlling of the laminating is case, however, as the resin is
diluted in a solution for easy application thereof, there is found
difficult problem of the tendency that the resin solution is
concentrated at the interface between the thermoplastic resin film
and the contact end of the tissue paper as shown in FIG. 1. This
interrupts the perforation of the thermoplastic resin film, and
causes no sharp print images.
[0012] For implementing high quality prints, there is provided
method of fabricating a heat-sensitive stencil sheet, in which a
porous resin layer is provided between the thermoplastic resin film
and the tissue paper. However, the use of a solution diluted with
solvent is also questioned because it enters in and plugs up the
pores in the porous resin layer. Also, if the solvent is an organic
material, it may dissolve the porous resin layer itself.
[0013] In case that the thermoplastic resin film and the tissue
paper used for heat-sensitive stencil sheet are bonded each other
by an ionizing radiation-curable resin, the tissue paper used for
heat-sensitive stencil sheet has to be impregnated with the
ionizing radiation-curable resin for controlling laminating action,
otherwise results the difficulty in controlling of above mentioned
laminating.
SUMMARY OF THE INVENTION
[0014] It is hence an object of the present invention to provide an
improved tissue paper used for heat-sensitive stencil sheet, an
improved heat-sensitive stencil sheet, and method of fabricating
the same which can eliminate the above drawbacks.
[0015] Through a series of experiments, we have found means for
overcoming the foregoing drawbacks. The means may basically include
the use of a tissue paper used for heat-sensitive stencil sheet,
the tissue paper is made of natural fibers, synthetic fibers, or
their mixture, which being impregnated with an ionizing
radiation-curable resin material, and thereby, the primary
requirements, such as (1) an excellent passing-through of printing
ink, (2) the case of perforation, (3) no releasing of the fibers,
(4) a prolonged durability for printing action, and (5) the
productivity, are attained.
[0016] Namely, the above and other objects of tho present invention
are achieved by the features of the present invention which
comprise: (1) a tissue paper used for heat-sensitive stencil sheet
comprising natural fibers, synthetic fibers, or their mixture,
wherein the tissue paper used for heat-sensitive stencil sheet is
being impregnated with an ionizing radiation-curable resin
(identical as claim 1);
[0017] (2) a multi-layer paper consisting of two or more layers of
tissue papers for heat-sensitive stencil sheet, characterized by
the each tissue paper are combined one other, so that they are in a
mode separable to one other for separated utilizing thereof, and
the multi-layer paper is being impregnated with an ionizing
radiation-curable type of resin (identical as claim 2);
[0018] (3) a tissue paper used for heat-sensitive stencil sheet
according to paragraph (1), or a multi-layer paper according to
paragraph (2), wherein the tissue paper or the multi-layer paper is
being impregnated with an ionizing radiation-curable resin by a
size-press processing (identical as claim 3);
[0019] (4) a tissue paper used for heat-sensitive stencil sheet
according to paragraph (2), wherein the tissue paper used for
heat-sensitive stencil sheet is being impregnated with an ionizing
radiation-curable resin by a size press processing;
[0020] (5) a tissue paper used for heat-sensitive stencil sheet
impregnated with the ionizing radiation-curable resin, wherein the
tissue paper used for heat-sensitive stencil sheet is being
obtained by separation of a multi-layer paper according to any
paragraphs (2) or (4) (corresponding to claim 4, but not
identical);
[0021] (6) a tissue paper used for heat-sensitive stencil sheet,
wherein the tissue paper used for heat-sensitive stencil sheet is
being obtained by radiating a tissue paper used for heat-sensitive
stencil sheet according to any one paragraph selected from
paragraph (1), (3) and (5) to an electron beam (corresponding to
claim 5, but not identical);
[0022] (7) a heat-sensitive stencil sheet having a thermoplastic
resin film being bonded to a tissue paper used for heat-sensitive
stencil sheet, wherein the tissue paper is being obtained by
irradiating tissue paper given by separation process of a
multi-layer paper according to any paragraphs (2) or (4) to an
electron beam;
[0023] (8) a heat-sensitive stencil sheet, in which there are
provided a thermoplastic resin film, the thermoplastic film being,
at surface of one side thereof, bonded by point-bonding
(spot-bonding) to a tissue paper used for heat-sensitive stencil
sheet according to any one paragraph selected from paragraphs (1),
(3), (5) and (6), and an anti-sticking layer on the other surface
of the thermoplastic resin film (corresponding to claim 6, but not
identical); and,
[0024] (9) a heat-sensitive stencil sheet, wherein there are
provided a porous resin layer on one side of the thermoplastic
resin film, and thereto is provided a tissue paper used for
heat-sensitive stencil sheet, the tissue paper is being impregnated
with an ionizing radiation-curable resin and being bonded the
thermoplastic resin film by point-bonding with using an ionizing
radiation-curable resin, and on the other side of the thermoplastic
resin film is provided with an anti-sticking layer (corresponding
to 7).
[0025] Also the above and other objects of the present invention
are achieved by the other features of the present invention which
comprise: (10) a method of fabricating a tissue paper used for
heat-sensitive stencil sheet, the tissue paper is made of natural
fibers, synthetic fibers, or their mixture, and being impregnated
with an ionizing radiation-curable resin, comprising step of
impregnating the tissue paper used for heat-sensitive stencil sheet
with an ionizing radiation-curable resin by a size-press
processing;
[0026] (11) a method of fabricating A multi-layer paper consisting
of a plural layer of tissue papers for heat-sensitive stencil sheet
in which each tissue paper are combined one other, so that they are
in a mode separable to one other for their separated utilizing,
comprising step of impregnating the multi-layer paper with a
ionizing radiation-curable resin by a size press processing;
[0027] (12) a method of fabricating a heat-sensitive stencil sheet
comprising steps of; placing a tissue paper used for heat-sensitive
stencil sheet according to any one paragraph selected from
paragraphs (1), (3), (5) and (6) on one side of a thermoplastic
resin film or a porous resin layer provided on a thermoplastic
resin film, and irradiating the placed tissue paper to an electron
beam thereby perfecting bonding between the tissue paper and one
side of the thermoplastic resin film or the porous resin layer
provided on the thermoplastic resin film (corresponding to claim 8,
but not identical); and,
[0028] (13) a method of fabricating a heat-sensitive stencil sheet
comprising steps of; further applying an ionizing radiation-curable
resin onto one side of a tissue paper used for heat-sensitive
stencil sheet according to any one paragraph selected from
paragraphs (1), (3), (5) and (6) contacting the resin-applied side
of the tissue paper with one side of a thermoplastic resin film or
a porous resin layer provided on a thermoplastic resin film,
irradiating the contacted one to an electron beam, thereby
perfecting bonding between tho tissue paper and one side of the
thermoplastic resin film or the porous resin layer provided on the
thermoplastic resin film (corresponding to claim 9, but not
identical).
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 is a cross sectional view of a conventional
heat-sensitive stencil sheet showing a typical bonding
condition;
[0030] FIG. 2 is a cross sectional view of a heat-sensitive stencil
sheet of the present invention showing a bonding condition;
[0031] FIG. 3 is a cross sectional view of tissue papers for
heat-sensitive stencil sheet which are used after separation from a
multi layer paper each other according to the present
invention;
[0032] FIG. 4 is a cross sectional view of tissue papers for
heat-sensitive stencil sheet which are used after separation from a
multi-layer paper each other according to the present invention;
and
[0033] FIG. 5 is a cross sectional view of a laminating process
according to the present invention.
[0034] FIG. 6 is a schematic cross sectional view of one embodiment
of a porous resin layer according to the present invention;
[0035] FIG. 7 is a perspective view of another embodiment of a
porous resin layer according to the present invention;
[0036] FIG. 8 is a schematic cross sectional view of a further
embodiment of a porous resin layer according to the present
invention;
[0037] FIG. 9 is a schematic cross sectional view of a still
further embodiment of a porous resin layer according to the present
invention;
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0038] The present invention will now be explained in more detail
below.
[0039] As a first feature of the present invention, there is
provided a tissue paper used for heat-sensitive stencil sheet
comprising natural fibers, synthetic fibers, or their mixture as is
impregnated with an ionizing radiation curable type of resin
material as, described in above paragraph (1). As the tissue paper
used for heat-sensitive stencil sheet is impregnated with the
ionizing radiation-curable resin material, it can be bonded with no
use of an adhesive to one side of a thermoplastic resin film or a
porous resin layer coated side of a porous resin layer coated
thermoplastic resin film. Also, as the tissue paper has
preliminarily been impregnated with the resin material, it can be
accompanied with a point bonding (spot-bonding) which has a width
less than or nearly equal to that of fiber as shown in FIG. 2, but
not FIG. 1 so as to favor the perforation. Moreover, when the
tissue paper is significantly stressed before bonded to one side of
a thermoplastic resin film or the coated side of a porous resin
layer-coated thermoplastic resin film, it can be cured by
application of electron beam or ultraviolet ray, without any
deformation. This allows the surface smoothness of the film to be
controlled with ease during the laminating action, thus improving
the productivity.
[0040] The tissue paper impregnated with an ionizing
radiation-curable resin material according to the present invention
may be made of materials selected from (1) natural fibers such as
mulberry, mitsumata, or Manila hemp, (2) synthetic fibers such as
rayon, vinylon, polyester, or nylon, and (3) a mixture of (1) a
natural fiber and (2) a synthetic fiber. The diameter of each fiber
is preferably not greater thin 40 .mu.m and more preferably ranges
1 to 20 .mu.m. If size of the diameter is smaller than 1 .mu.m, its
tensile strength will be declined. When exceeding 40 .mu.m, the
passing-through of printing ink will be disturbed thus producing
blank spot called voids in prints. Also, the length of each fiber
ranges preferably from 0.1 to 10 mm and more preferably from 1 to 6
mm. If the length is shorter than 0.1 mm, the tensile strength will
be declined. When exceeding 10 mm, the dispersion will hardly be
uniform.
[0041] The basis weight of the thermoplastic tissue paper used for
heat-sensitive stencil sheet is preferably 5 to 20 g/m.sup.2 and
more preferably 8 to 15 g/m.sup.2. If the basis weight exceeds 20
g/m.sup.2, the passing-through of printing ink will be declined
thus lowering the image sharpness in prints. When less than 5
g/m.sup.2, the deposition of paper will be difficult.
[0042] The ionizing radiation-curable resin material used in the
present invention may include polymers having double bonds of
radical polymeric and relatively low weight, while are instanced as
(meth)acrylete-polyeste- rs, -polyethers, -acryl resins, -epoxy
resins, -urethane resins, and a radical polymeric mono-functional
monomer, multi-functional monomer, or the like, and if polymeric
cross-linking by means of ultraviolet light is intended a photo
polymerization-initiator is also included. Any these known ionizing
radiation-curable type of resin may be used in the present
invention. From the point eliminating possible danger to make
progress the curing action on the resin material with ultraviolet
ray during stored, the ionizing radiation-curable type of resin
material may not contain the photo polymerization-initiator, and
can preferably be cured by electron beam for improving the storage
stability of the tissue paper after the resin is applied. And from
both points of strength and flexibility, urethane-acrylate type of
resin is favorably used as the ionizing radiation-curable resin
material.
[0043] The urethane-acrylate used in the present invention can be
obtained by reacting with multi-functional alcohol,
multi-functional isocyanate and acrylates having hydrogen group.
Characteristic examples may include an additive-reaction product,
of polyether-diols, which is produced by reaction of
multi-functional organic acid such as sabacic acid, malcic acid,
terephtahic acid and the like, and multi-valent alcohols (such as
ethyleneglycohol, propyleneglycohl, 1,4-buthyleneglycohol,
1,6-hexane-diol, and the like), diisocyanates (such as
tolylenediisocyanate, 4,4-diphenylmethanediisocyanate, hydrogenated
tolylenediisocyanate, isophoronodiisocyanate,
1,6-hexamethylenediisocyana- te and the like), and
2-hydroxyethyl-acrylate, and an additive-reaction product of
polyether-diols (such as polyethleneglycohol,
polypropyleneglycohol, polytetramethyleneglycohol, and the like),
diisocyanates (such as tolylenediisocyanate,
4,4'-diphenylmethanediisocya- nate, hydrogenated
tolylenediisocyanate, isophoronediisocyanate,
1,6-hexamethylenediisocyanate and the like), and
2-hydroxyethyl-acrylate, and the like.
[0044] Character examples of the mono functional monomer are
(meth)acrylic ester, (meth)acryl amide, aryl compound, vinyl
ethers, vinyl esters, vinyl isomer cyclization compound, N-vinyl
compound, styrene, (meth)acrylic acid, crotonic acid, itaconic
acid, and other vinyl monomer. Characteristic examples of the
multi-functional monomer are diethylene glycol di(meth)acrylate,
tricthylene glycol di(meth)acrylate, tetraethylene glycol
di(meth)acrylate, trimethylol propane tri(meth)acrylate,
pentaerythlytol tetra(meth)acrylate, dipentaerythlytol
hexa(meth)acrylate, and
tris(.beta.-(meth)acryloiroxyethyl)isocyanurate.
[0045] As it second feature of the present invention, there is
provided a multi-layer paper consisting of a two or more layers of
tissue paper for heat-sensitive stencil sheet, in which the each
tissue paper are combined one other, so that they are in a mode
separable to one other for each utilization thereof, and the
multi-layer paper is being impregnated with an ionizing
radiation-curable type of resin, as described in paragraph (2).
[0046] With regard to a paper called a milled-combined paper which
is obtained by a milling process comprising steps of accompanying
plural layers in wetted state to a piled up state thereof and
drying it, a method for producing two or more tissue papers at once
from the milled-combined paper is now found out, in which, the
strength against separation at inter surface between paper layers
or the strength against peeling at inner layer of an intermediate
paper positioned in inside of a multi-layer paper consisting three
of more layers of paper is limited within a determined lowered
level, in accordance with the present invention. Methods of the
present invention are applicable effectively to the above-mentioned
method for producing two or more tissue papers at once from a multi
layer paper.
[0047] In other words, in the case of a multi-layer paper
consisting of two or more layers combined one other so that they
are in a state separable to one other for each utilization thereof,
if a known processing by resin is applied to tissue papers being
piled up, separation at inter layer is difficult, and a processing
by resin amounted to making a separable condition of inter layer is
also questioned, because it may release fibers from the paper layer
or result a lesser strength than that required for the paper.
[0048] Of cause, the processing by resin can executed after
separating, a plural of process is however required for every
separated papers, thus serious problem is caused with a missing
benefit of productivity.
[0049] With accordance to the present invention, although two or
more paper layers the state being interposed thereof are
impregnated with ionizing radiation-curable resin, the resin is not
cured an far as electron beam or ultra violet ray is not effected,
therefore easy separation is capable, and after separated one
other, the obtained one is combined with a thermoplastic film or a
porous resin layer provided on a thermoplastic film, then exposed
to an irradiation of electron beam or ultra violet ray, thereby a
good enough effect similar to that of the first feature of the
present invention can be obtained, with a significantly improved
productivity.
[0050] When curing by the use of ultraviolet radiation, if
necessary but unfavorable in usual, photo polymerization initiator
may be involved. Characteristic examples of the photo
polymerization initiator are, as mono-functional types,
2-ethythexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl
acrylate, 2-hydroxyethyl acryloil phosphate, tetrahydrofurfuryl
acrylate, and tetrahydrofurfuryl derivative acrylate, and as
multi-functional types, dicyclopentenyl acrylate, dicyclopentenyl
oxyethyl acrylate, 1,8-butanediol diacrylate, 1,4-butanediol
dincrylate, 1,6-hexanediol diacrylate, diethylene glycol
diacrylate, neopentyl glycol 400 diacrylate, polyethylene glycol
400 diacrylate, hydroxyesterpivalylate neopentyl glycol diacrylate,
triproplylene glycol diacrylate,
1,3-bis(3'-acryloxyethoxy-2'-hydroxypropyl)-5,5-dimethylhydan-
tion, hydroxyesterpivalylate neopentyl glycol derivative
diacrylate, and dipentaerythlyrol hexacrylate.
[0051] And, the use of multi layer paper with separation to
fragments thereof makes it possible to give a tissue paper used for
heat-sensitive stencil sheet which has a lowered basis weight and
an excellent passing-through of ink, both that are difficult to
attain by conventional techniques.
[0052] A combined web of the two or more layers which are then used
an the tissue papers of the present invention may be fabricated
from natural fibers such as mulberry, mitsumata, or Manila hemp,
synthetic fibers an rayon, vinylon, polyester, or polyacrylonitryl,
and their mixture. These materials can be flowed to, filtered by
and deposited on a screen in a known combination paper making
machine.
[0053] For ease of the separation or layers, it is desired to have
the fibers of each layer deposited differently. For example, one
layer is developed from the natural fibers while the other is
developed from the synthetic fibers as shown in FIG. 3. The natural
fiber layer creates hydrogen bonds for bonding the fibers together
while the synthetic fiber layer has binder fibers bonded to one
another by fusion bonding to increase the physical strength. At the
interface between the natural fiber layer and the synthetic fiber
layer, the binder fibers in the synthetic fiber layer may increase
the bonding strength to a level smaller than that in the layers.
The basis weight of the layers is preferably 2.0 to 20.0 g/m.sup.2
and more preferably 3.0 to 15.0 g/m.sup.3. If the bass weight is
smaller than 2.0 g/m.sup.2, the deposition of paper will be
difficult and also the physical strength will be lower for the
resultant heat-sensitive stencil sheet. When exceeding 20.0
g/m.sup.2, the passing-through of printing ink will be
declined.
[0054] An alternative method of fabricating two identical layers at
once is provided as illustrated in FIG. 4.
[0055] In the method, an intermediate layer may preferably be
fabricated from not the binder fibers but more slightly sized
fibers which provide a less level of the bonding strength. As the
intermediate layer between the two layers has the fibers not
tightly bonded to one another, the removal of the fibers may be
increased. This drawback can however be eliminated by preliminarily
impregnating with the ionizing radiation resin material which is
cured in the laminating action.
[0056] As a third feature of the present invention, there are
provided a tissue paper used for heat-sensitive stencil sheet
according to paragraph (1), wherein the tissue paper is being
impregnated with an ionizing radiation-curable resin by a
size-press processing, as described in paragraph (3) and a tissue
paper used for heat-sensitive stencil sheet according to paragraph
(2) wherein the tissue paper is being impregnated with an ionizing
radiation-curable resin by a size press processing.
[0057] (5) a tissue paper used for heat-sensitive stencil sheet
impregnated with the ionizing radiation-curable resin wherein the
tissue paper used for heat-sensitive stencil sheet is being
obtained by separation of a multi-layer paper according to any
paragraphs (2) or (4) (corresponding to claim 4, but not
identical);
[0058] (6) a tissue paper used for heat-sensitive stencil sheet,
wherein the tissue paper used for heat-sensitive stencil sheet is
being obtained by exposing a tissue paper used for heat-sensitive
stencil sheet according to any one paragraph selected from
paragraphs (1) ,(3) and (5) to ionizing irradiation (corresponding
to claim 5, but not identical);
[0059] With regard to the size-press processing in the present
invention, though the impregnation of the tissue paper used for
heat-sensitive stencil sheet with an ionizing radiation-curable
resin may includes, but not limited to, reverse roll coating,
gravure coating, offset, gravure coating, kiss coating, wire bar
coating, blade coating, transfer roll coating, die coating, and the
like by controlling viscosity of coating liquid, each those coating
techniques are effected from one side of surface only of a
substrate to be coated, thus homogeneous impregnation covering
whole layer thickness of the tissue paper is hardly effected by
those coating techniques. For the easy achievement of a smoothen
surface after lamination without releasing of fiber from tissue
paper treated, which is also one purpose of the present invention,
the size-press processing suited to a impregnating is the most
favorable coating, and thereby whole layer thickness of tissue
paper used for heat-sensitive stencil sheet is homogeneously
impregnated.
[0060] As a fourth feature of the present invention, there are
provided a tissue paper used for heat-sensitive stencil sheet
impregnated with the ionizing radiation-curable type of resin, the
tissue paper is that being obtained by separating of a multi-layer
paper according to any paragraphs (2) or (4), as described in
paragraph (5)
[0061] According to the feature of the present invention, it is
possible to obtain easy a tissue paper used for heat-sensitive
stencil sheet which has a lowered basis weight and an excellent
passing-through of ink, both that are difficult to attain by
conventional techniques.
[0062] As a fifth feature of the present invention, there are
provided a tissue paper used for heat-sensitive stencil sheet being
obtained by exposing a tissue paper used for heat-sensitive stencil
sheet according to any one paragraph selected from paragraphs (1),
(3) and (5) to electron beam, as described in paragraph (6); and a
tissue paper used for heat-sensitive stencil sheet being obtained
by exposing a tissue paper used for heat-sensitive stencil sheet
according to any paragraphs (2) or (4) to electron beam, as
described in paragraph (7).
[0063] The tissue paper used for heat-sensitive stencil sheet by
the feature of the present invention, an ionizing radiation curable
resin impregnated in the tissue paper used for heat-sensitive
stencil sheet is that being cured by exposure to an electron beam
as ionizing irradiation, thereby bonding strength between fibers,
strength against stretching, ink passing-through, all those
properties are simultaneously required for thermal tissue paper
used for heat-sensitive stencil sheet, attained.
[0064] Hereinafter, heat-sensitive stencil sheets derived from
above-mentioned tissue paper used for heat-sensitive stencil sheets
by present invention, and production methods thereof are described
below.
[0065] As a sixth feature of the present invention, there is
provided a heat-sensitive stencil sheet having a thermoplastic
resin film which is, at its surface of one side, bonded by
point-bonding (spot-bonding) to a tissue paper used for
heat-sensitive stencil sheet according to any one paragraph
selected from paragraphs (1), (3), (5), (6), and a heat-sensitive
stencil sheet according to paragraph (7), an anti-sticking layer on
the other surface of the thermoplastic resin film, wherein there is
a porous resin layer provided to surface of one side of the
thermoplastic resin film, the thermoplastic resin film, on the
other surface thereof, is bonded by point-bonding to a tissue paper
used for heat-sensitive stencil sheet, an anti-sticking layer, and
the tissue paper being impregnated with an ionizing
radiation-curable type of resin, as described in paragraph (8).
[0066] The heat-sensitive stencil sheet of the present invention
allows the tissue paper used for heat-sensitive stencil sheet and
the thermoplastic resin film to be ideally bonded to each other,
thin improving the ease of perforation and creating sharp images in
prints. Also, as the tissue paper is impregnated with an ionizing
radiation-curable resin material, its mechanical strength can be
improved hence contributing to the economical production of the
heat-sensitive stencil sheet, and which exhibits no removal of the
fibers and thus in high in the quality. Moreover, as the protective
layer to prevent sticking is provided on the film, it can protect a
thermal head from sticking with a fused surface of the
thermoplastic film, thus it enables the preparation of a master
that yields solid print.
[0067] The anti-sticking layer may be a thin layer containing
silicon oil, silicon resin fluorine resin, a surface active agent,
a destaticizer, a heat resistant agent, an anti-oxidization agent,
organic particles, inorganic particles, a pigment, a dispersant, an
antiseptic agent, and an antifoaming agent. The thickness of the
thin layer ranges preferably from 0.005 to 0.4 .mu.m and more
preferably from 0.01 to 0.4 .mu.m.
[0068] The method of forming the anti-sticking layer on the
heat-sensitive stencil sheet of the present invention is not
limited to but may be made by applying and drying a coated solution
layer made of water or a solvent with the use of a roll coater, a
gravure coater, a reverse coater, or bar coater.
[0069] The thermoplastic resin film according to the present
invention may be selected from known polyester, polyamide,
polypropylene, polyethylene, polyvinyl chloride, polyvinylidene
chloride, and their copolymer. Preferably, polyester film is
employed for favorable sensitivity to perforation.
[0070] Characteristic examples of the polyester film are
polyethylene terephthalate, copolymer of ethylene terephthalate and
ethylene-isophthalate, and copolymer of hexamethylene terephthalate
and cyclohexanedimethylene terephthalate. For improving the
sensitivity to perforation, the copolymer of ethylene terephthalate
and ethylene-isophthalate or the copolymer of hexamethylene
terephthalate and cyclohexanedimethylene terephthalate is favorably
selected.
[0071] The thermoplastic resin film used according to the present
invention may be doped with, if desired, an flame resist agent, a
thermal stabilizer, an anti-oxidant, an ultraviolet absorbent, a
destaticizer, a pigment, a dye, an organic lubricant such are wax
or fatty acid ester, and antifoaming agent such as polysiloxane.
Moreover, the lubricating properties may be applied if necessary.
The lubricating properties are implement by application of, but not
limited to, inorganic particles such as clay, mica, titanium oxide,
calcium carbonate, kaolin, talc, and wet or dry silica, organic
particles such as acrylic acids or styrene, built-in particles, or
a surface active agent.
[0072] The thickness of the thermoplastic resin film used according
to the present invention is preferably 0.1 to 5.0 .mu.m and more
preferably 0.1 to 3.0 .mu.m. If the thickness exceeds 5.0 .mu.m the
porous properties will be declined. When smaller than 0.1 .mu.m,
the layer generation stability or the resistance to the printing
action will be declined.
[0073] As a seventh feature of the present invention, there are
provided a heat-sensitive stencil sheet according to paragraph (8),
wherein there are provided a porous resin layer on one side of the
thermoplastic resin film, and thereto is provided a tissue paper
used for heat-sensitive stencil sheet, the tissue paper is being
impregnated with an ionizing radiation-curable resin and being
bonded the thermoplastic resin film by point-bonding with using an
ionizing radiation-curable resin, and on the other side of the
thermoplastic resin film is provided with an anti-sticking layer,
as described in paragraph (9).
[0074] The heat-sensitive stencil sheet by the feature of the
present invention, unlike the heat-sensitive stencil sheet by the
method defined in above paragraph (8), has the porous resin layer
provide between the tissue paper and the thermoplastic resin film
hence allowing printing ink to be minutely dispersed as passed
through the master. Accordingly, the printing ink can thus produce
a quality solid image with its minimum transfer amount. Also, as
the print through as transfer of thus printing ink to the back of a
printing paper can be minimized thus inhibiting strike-through.
Moreover, the bonding between the porous resin layer and the tissue
paper used for heat-sensitive stencil sheet can favorably be
implemented as illustrated in FIG. 2, hence minimizing declination
in the passing-through of printing ink.
[0075] The term "porous resin layer" used herein means a porous
layer of the foamy shape assembly, including a multiplicity of wall
2a defines cells equipped with ceilings 2b, assuming that the
surface of the film 1 is a floor, those walls 2a and ceilings 2b
constitute resin layer 2, as instanced in FIG. 6, a honey combed
structure equipped with walls 2b instead of the ceilings, and with
the exception of the floor, as instanced in FIG. 7, a group of
foamy-like cells as instanced in FIG. 8 is an assembly of
granular-shaped or fabric-shaped resin segments pieces 2b coupled
together, instead of the ceilings and walls, as instanced in FIG.
9, and the like. However the porous resin layer is not restricted
to these instruction.
[0076] The porous resin layer is favorably produced by depositing a
resin solution or dispersion by using a solvent, or solvents
including water.
[0077] Average diameter of the pores of the above mentioned porous
resin layer is possible to be a smaller then that of conventional
porous resin layer, and especially, a range from 5 .mu.m to 20
.mu.m of average pore size is particularly suited to a W/O-type
(water in oil type) emulsion ink which has a excellent
dispersibility and therefore is used for general stencil printing
or in other words stencil printing, thus a high quality print which
has a excellent solid area is obtained.
[0078] In the depth direction of the layer, each pore in the porous
resin layer are connected each other, while in the traverse
direction of the layer, the each pore are hardly connected, thereby
sideward deviated penetration of the ink in heat-sensitive stencil
sheet is decreased. Accordingly, by mean of the porous resin layer,
it is possible to suppress a transmitting of the excess ink.
Thereby, in comparison with conventional supporting substrates
which have almost same average size but in fiber of pores as that
of the present invention, so-called print-through can be avoided
more effectively.
[0079] With regard to formulation of the porous resin layer, in
view of ink dispersibility, the most favorable one is an assembly
of cells having honey combed structure. However in view of
manufacturing, a favorable is a foamy film formed by applying a
fluid containing a W/O type emulsion as main ingredient onto a
thermoplastic film and drying it, because it is producible a stable
coating, and if desired, the foamed structure can be altered to the
another structure of more similar to honey combed one.
[0080] The porous resin layer in the present invention is favorable
to have many pores in inside and on surface of the resin layer, in
which those pores in inside of the resin layer are connected in
thickness direction, from point of ink-passiveness.
[0081] The average diameter of the pores in the porous resin layer
ranges generally from 1 .mu.m to 50 .mu.m, preferably from 3 .mu.m
to 30 .mu.m and more preferably from 5 .mu.m to 20 .mu.m. If the
average diameter is smaller than 1 .mu.m, the passing-through of
printing ink will be declined. When the printing ink has a lower
level of the viscosity for improving its passing-through, it may
smear or blur during the printing action and finally escape from
both ends of the printing drum or the trailing end of the printing
master. Also, the porous resin layer will be declined in the
porosity and the perforation with a thermal head will is
significantly be interrupted. When its average pore diameter
exceeds 50 .mu.m, the porous fiber layer will fail to retain the
printing ink which thus runs out from between the printing drum and
the film, hence causing unwanted stains or smears. Namely, the
printing action may produce unfavorable quality of prints when the
average diameter is either too large or small, resulting smearing,
blurring or set-off. When the porous resin layer is arranged with
an average pore diameter of not greater than 20 .mu.m, it causes
the passing-through of printing ink to become difficult as its
thickness increases. Accordingly, the transfer of printing ink to a
sheet of paper to be printed will be controlled by modifying the
thickness of the layer. If the layer is not uniform in the
thickness, it may produce printing unevenness.
[0082] The thickness of the porous resin layer ranges preferably
from 2 .mu.m to 50 .mu.m and more preferably from 5 .mu.m to 30
.mu.m. If its thickness is smaller than 5 .mu.m, the porous resin
layer may hardly remain behind the perforations produced by the
thermal head and fails to control the transfer of the printing ink,
thus causing back printing smears. The effect of controlling the
transfer of printing ink is increased in proportion to the
thickness of the porous resin layer. As a result, the transfer of
printing ink to a sheet of paper to be printed can be controlled by
modifying the thickness of the porous resin layer.
[0083] The density of the porous resin layer ranges generally from
0.01 g/cm.sup.3 to 1 g/cm.sup.3 and preferably from 0.1 g/m.sup.3
to 0.7 g/cm.sup.3. If its density is smaller than 0.01 g/cm.sup.3,
the porous resin layer will be declined in the physical strength
and become fragile.
[0084] The amount of the porous resin layer is 0.1 to 10
g/cm.sup.3, preferably 0.5 to 7.0 g/cm.sup.3, and more preferably
1.0 to 5.0 g/cm.sup.2. If its amount is too great, the porous resin
layer may interrupt the passing-through of printing ink thus
declining the quality of prints. When not greater than 0.1
g/cm.sup.3, the transfer of printing ink may be controlled with
much difficulty. When exceeding 10 g/cm.sup.3, the passing-through
of printing ink will be declined.
[0085] The porous resin layer may be made from vinyl resins such as
polyvinyl acetate, polyvinyl butyral, vinyl chloride-vinyl acetate
copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl
chloride-acrylonitryl copolymer, or styrene-acrylonitryl copolymer,
polyamide such as polybutylene or nylon, and cellulose derivatives
such as polyphenyl oxide, (meth)acrylic ester, polycarbonate,
polyurethane, acetyl cellulose, acetylbutyl cellulose, or
acetylpropyl cellulose. Alternatively, two or more different resins
may be mixed.
[0086] The porous resin layer may he doped with an additive such as
a filler for determining the formation, the strength, and the pore
diameter, if necessary. The filler include pigments, powder, and
fabrics. The filler is preferably provided in the form of
needle-like configuration. The filler may be selected from mineral
needle fillers such as magnesium silicate, sepiolite, potassium
titanate, wollastonite, zonotolite, or gypsum fiber, sythetic
mineral needle fillers such as non-oxide needle whisker, oxide
whisker, or bi-oxide whisker, and sheet fillers such as mica, glass
flake, or talc.
[0087] The pigment may be selected from inorganic or organic
pigments, organic polymers such as polyvinyl acetate, polyvinyl
chloride, or polyacrylic ethyl, zinc oxide, titan dioxide, calcium
carbonate, and silica. Namely, Micro-capsule, Matsumoto
micros-sphere, a product of Matsumoto Oil Pharmacy can be used.
[0088] The additive may preferably be 5% to 200% in relation to the
resin. If not greater than 5%, the additive will hardly increase
the bending rigidity. When the additive exceeds 200%, the bonding
to the film will be declined.
[0089] The porous resin layer may be doped with a destaticizer,
stick protector, a surfactant, an antiseptic agent, and an
antifoaming agent.
[0090] Next, methods of forming the porous resin layer in the
heat-sensitive stencil sheet of the present invention will be
described.
[0091] As described above, The porous resin layer used according to
the present invention is preferably arranged to have a structure
where there are a multiplicity of pores in the interior and surface
therefore. More preferably, the pores are provided continuously
along the thickness direction in the porous layer for ease of the
passing-through of printing ink. The porous resin layer is
favorably produced by depositing a resin solution or dispersion by
using a solvent, or solvents including water.
[0092] A first porous resin layer forming the method involves
applying and drying a liquid coating produced by dissolving and/or
dispersing a resin material into a solvent mixture of a good
solvent and a poor solvent. It is necessary to have the good
solvent arranged volatile at a lower temperature than that of the
poor solvent. When the good solvent and the poor solvent are
provided one type each, the boiling point of the good solvent has
to be relatively lower than that of the poor solvent. As the good
solvent and the poor solvent are arbitrarily selected, their
difference in the boiling point ranges preferably from 15 to
40.degree. C. for forming the porous resin layer with desired
properties. If the difference in the boiling point is lower than
10.degree. C., the two solvents exhibits a small difference in the
evaporating duration and may develop a less porous structure. When
the boiling point of the poor solvent is too high, the drying takes
a considerable length of time thus declining the productivity. It
is hence desired that the boiling point of the poor solvent is not
higher then 150.degree. C.
[0093] The concentration of the resin in the liquid coating ranges
from 5% to 30% depending on the type. If lower than 5%, the
diameter of the pores will be too large or the porous resin layer
will be irregular in the thickness. When the concentration exceeds
30%, the porous resin layer will hardly be developed. Even if the
porous resin layer is developed, its pore diameter may be decreased
thus declining the properties.
[0094] The average diameter of the pores in he porous resin layer
depends significantly on the poor solvent in the atmosphere. The
higher the ratio to the good solvent, the greater the rate of
aggregation becomes thus increasing the pore average diameter.
[0095] As the dosage of the poor solvent is varied depending on the
resin type and the solvent type, it has to be determined through
experiment. In common, the greater the dosage of the poor solvent,
the greater the pore average diameter in the porous resin layer
becomes. However, if the dosage of the poor solvent is too large,
the resin itself may be separated out making the liquid coating
unstable.
[0096] A second method of forming the porous resin layer is
arranged, as disclosed it Japanese Patent Laid-open Publication
(Heisei)11-235855, where a fluid coating of W/O emulsion is applied
and dried on a thin film. A resin (which may include additives such
as a filler and an emulsifier) in the fluid coating is turned to a
resultant layer structure while water evaporated leaves the pores
through which printing ink is passed. In this method, the porous
layer may be doped with desired additives such as a filler and an
emulsifier for determining the shape, the strength, the pore
diameter, and the stiffness. The filler may preferably be selected
from needle, sheet, and fiber types.
[0097] The W/O emulsion is preferably based on a highly lipophilic
surface active agent having 4 to 6 of HLB (hydrophilic-lipophilic
balance). The W/O emulsion may be more stable and uniform when a
surface active agent having 8 to 20 of HLB is mixed in the water.
Alternatively, a polymer surface active agent may be used for
creating a stable and uniform emulsion. It is also a good idea for
creating a stable and uniform emulsion to add its water with a
thickening agent such a polyvinyl alcohol or polyacrylic acid.
[0098] The method of forming the porous resin layer its not limited
to the above described methods.
[0099] The liquid coating on the thermoplastic resin film for
forming tho porous resin layer according to the present invention
may be applied by using means selected from blade, transfer roll,
wire bar, reverse roll, gravure, die, and other known coating
techniques. The die coating method is preferably employed since its
airtight system can minimize evaporation of the solvent thus to
maintain in the liquid coating stable.
[0100] As an eighth feature of the present invention, there are
provided a method of fabricating a tissue paper used for
heat-sensitive stencil sheet according to paragraph (1), comprising
step of impregnating a tissue paper used for heat-sensitive stencil
sheet with a ionizing radiation-curable resin by a size-press
processing, as described in paragraph (10), and a method of
fabricating a multi-layer paper according to paragraph (2)
comprising step of impregnating a multi-layer paper with a ionizing
a radiation-curable resin by a size-press processing) as described
in paragraph (11).
[0101] With regard to the size-press processing in the present
invention, though the impregnation of the tissue paper used for
heat-sensitive stencil sheet with an ionizing radiation-curable
resin may includes, but not limited to, reverse roll coating,
gravure coating, offset gravure coating, kiss coating, wire bar
coating, blade coating, transfer roll coating, die coating, and the
like by controlling viscosity of coating liquid, each those coating
techniques are effected from one side of surface only of a
substrate to be coated, thus homogeneous impregnation covering
whole layer thickness of the tissue paper is hardly effected by
those coating techniques.
[0102] For the easy achievement of a smoothen surface after
lamination without releasing of fiber from tissue paper treated,
which is also one purpose of the present invention, the size-press
processing suited to a impregnating is the most favorable coating,
and thereby whole layer thickness of tissue paper used for
heat-sensitive stencil sheet is homogeneously impregnated.
[0103] Though the viscosity of ionizing radiation-curable resin may
be controlled by using dilute, or an organic solvent, a water
soluble or dispersible agent may preferably be used in view of the
environmental protection or the cost of an extra anti-explosion
facility.
[0104] Hereinafter, heat-sensitive stencil sheets using
above-mentioned tissue paper used for heat-sensitive stencil sheets
by present invention, and production methods thereof are
specified.
[0105] As a ninth feature of the present invention, there are
provided a method of fabricating a heat-sensitive stencil sheet
comprising steps of; applying an ionizing radiation-curable resin
onto one side of a tissue paper used for heat-sensitive stencil
sheet according to any one paragraph selected from paragraphs (1),
(3), (5), (6) and (7), placing the tissue paper used for
heat-sensitive stencil sheet on one side of a thermoplastic resin
or a porous resin layer provided upon a thermoplastic resin film,
so as to direct the resin-applied side of the tissue paper used for
heat-sensitive stencil sheet facing to the surface to be placed
thereon, exposing them to electron beam, thereby perfecting bonding
between the tissue paper used for heat-sensitive stencil sheet and
one side of the thermoplastic resin film or the porous resin layer
provided upon the thermoplastic resin film, as described in
paragraph (12);
[0106] In accordance of the feature of the present invention, a
step of applying an adhesive may eliminate so as to improve the
productivity, and also, this allows a laminating process
substantially under ideal conditions (as shown FIG. 2). In the
laminating process, the tissue paper remains tensioned and thus can
be cured without resulted deforming, facilitating to determining a
degree of the surface smoothness of the film.
[0107] For example, a laminating process using a roller of mirror
surface as known process such as a revealed in Japanese Examined
Patent Publication of Tokkou IIei 3-52354 is applicable. A tissue
paper impregnated with an ionizing radiation-curable resin material
is placed over a film running directly on the mirror surface of the
roller and exposed to electron beam for curing without receiving no
stress, as shown FIG. 5. As the tissue paper being tensioned, it
can be cured under a tensioned state and its film surface can
consistently be improved in the smoothness on the mirror surface of
the roller, as compared with the conventional method where a tissue
paper once cured is urged and deformed by an external stress along
its contracting direction thus declining the film smoothness.
[0108] The amount of the ionizing radiation-curable resin material
to be applied to the tissue paper used for heat-sensitive stencil
sheet is preferably 5 to 40 percents by weight based on the basis
weight of the master and more preferably 10 to 30 percents by
weight. If the amount is not higher than 5 percents by weight, the
bonding strength will be declined. When exceeding 40 percents by
weight, the pores in tho tissue paper will be filled with the resin
material thus declining the passing-through of printing ink.
[0109] The radiation may be carried out by a known technique. For
example, when the radiation of electrons is used for curing, its
energy ranges from 50 to 1000 KeV or preferably 100 to 300 keV and
its source may be selected from Cockcroft-Walton, Van de Graaff,
resonance transformer, insulating core transformer, linear,
electron-curtain, Dynamitron, and high frequency electron
accelerators.
[0110] When the ultraviolet ray is used for curing, its radiation
source is preferably selected from ultra-high-voltage mercury lamp,
high-voltage mercury lamp, low-voltage mercury lamp, carbon arc
lamp, xenon lamp, and metal halide lamp. For increasing the curing
speed, either a metal halide lamp or a no-electrode discharge lamp
D bulb is more preferably used which emits continuous wavelength
between 320 to 450 nm.
[0111] In the course of exposure, the tissue paper used for heat
sensitive stencil sheet and the thermoplastic resin film or the
porous resin layer coated thermoplastic resin film have to be
equally tensioned at the surface. This can be implemented when the
web is exposed to the radiation while running directly on the
mirror surface of a roller as shown in FIG. 5. As the mirror
surface of the roller is increased in the temperature by the
radiation of electron beam or ultraviolet ray, it may preferably be
equipped with a cooling system.
[0112] The exposure to the radiation may be either side of the web,
the thermoplastic resin film side or the tissue paper used for
heat-sensitive stencil sheet side. In view of the efficiency, the
tissue paper side of the web may be exposed to the radiation.
[0113] For example, the tissue paper impregnated with an ionizing
radiation-curable resin material is placed over a film directly on
the mirror surface of a roller and exposed to electron beam or
ultraviolet ray for curing without recieving no stress. As the
tissue paper remains tensioned, it can be cured under a degree
tension and its film surface can consistently be improved in the
smoothness on the mirror surface of the roller as compared with the
conventional method where a tissue paper once cured is urged and
deformed by an external stress along its contracting direction thus
declining the film smoothness.
[0114] The amount of the ionizing radiation-curable resin material
to be applied to the tissue paper used for heat-sensitive stencil
sheet is preferably 5 to 40 percents by weight based on the basis
weight of the master and more preferably 10 to 30 percents by
weight. If the amount is not higher than 5 percents by weight, the
bonding strength will be declined. When exceeding 40 percent by
weight, the pores in the tissue paper will be filled with the resin
material thus declining the passing-through of printing ink.
[0115] The radiation may be carried out by a known technique. For
example, when the radiation of elections is used for curing, its
energy ranges from 50 to 1000 keV or preferably 100 to 300 keV and
its source may be selected from Cockcroft-Walton, Van do Graaff,
resonance transformer, insulating core transformer, linear,
electron-curtain, Dynamitron, and high frequency electron
accelerators.
[0116] When the ultraviolet ray is used for curing, its radiation
source is preferably selected from ultra-high-voltage mercury lamp,
high-voltage mercury lamp, low-voltage mercury lamp, carbon arc
lamp, xenon lamp, and metal halide lamp. For increasing the curing
speed, either a metal halide lamp or a no-electrode discharge lamp
D bulb is more preferably used which emits a continuous wavelength
between 320 to 450 nm.
[0117] The exposure to the radiation may be either side of the web,
the thermoplastic resin film side or the tissue paper used for
heat-sensitive stencil sheet side. In view of the efficiency, the
tissue paper side of the web may be exposed to the radiation.
[0118] As a tenth feature of the present invention, there are
provided a method of fabricating a heat-sensitive stencil sheet
comprising steps of; further applying an ionizing radiation-curable
resin onto one side of a tissue paper used for heat-sensitive
stencil sheet according to any one paragraph selected from
paragraphs (1), (3), (5), (6) and (7), contacting the resin-applied
side of the tissue paper used for heat-sensitive stencil sheet with
one side of a thermoplastic resin film or a porous resin layer
provided on a thermoplastic resin film, exposing the contacted one
to electron beam, thereby perfecting bonding between the tissue
paper used for heat-sensitive stencil sheet and one side of the
thermoplastic resin film or the porous resin layer provided on the
thermoplastic resin film; as described in paragraph (13).
[0119] According to the feature of the present invention, the resin
treatment step of tissue paper used for heat-sensitive stencil
sheet is isolated from the laminating step of the resin treated
tissue paper with thermoplastic resin film or the porous resin
layer provided on the thermoplastic film. Therefore, necessarily
small amount only of adhesive for eliminating the fiber-release
from the tissue paper and holding a required strength level of
heat-sensitive stencil sheet may impregnate, thereby, the problem
in passing through of ink is significantly decreased. Moreover, the
bonding between the porous resin layer and the tissue paper used
for heat-sensitive stencil sheet can favorably be implemented as
illustrated in FIG. 2.
[0120] It is essential for providing an ideal condition of bonding
(spot-bonding) to apply the solvent-free adhesive to the tissue
paper. When the adhesive has a higher level of the viscosity, it
may cause removal of the fibers thus creating defectives.
[0121] The amount of the ionizing radiation-curable resin material
as an adhesive to be applied to the tissue paper used for
heat-sensitive stencil sheet is preferably 2 to 30 wt. %/m.sup.2 on
the basis weight of the master and more referable 5 to 20 wt.
%/m.sup.2. If the amount is less than 2 wt. %/m.sup.2, eliminating
the fiber-release from the tissue paper and holding a required
strength level of heat-sensitive stencil sheet will be declined.
When exceeding 30 wt. %/m.sup.2, the pores in the tissue paper will
be filled with the resin material thus declining the
passing-through of printing ink.
[0122] With to the irradiation-curable resin used as an adhesive in
the present invention, it is required that it is not diluted with
solvent while controlled in viscosity by heating, during its
applying to the tissue paper so that the release of fibers from the
tissue paper and unfavorable coating is avoided. Namely, the
adhesive may preferably be heated to decrease its viscosity to
below 3000 cps during the application. More preferably, the
viscosity ranges from 800 to 1500 cps. If not higher than 300 cps,
the bonding condition will hardly be ideal. Also, when the tissue
paper is bonded to the porous resin layer, its adhesive may block
the pores thus interrupting the passing-through of printing ink.
When exceeding 3000 cps, the tissue paper will be increased in the
removal of fibers.
[0123] If it is diluted with solvent to control viscosity, it
spreads over and wets the thermoplastic film, thus an ideal bonding
does not attain, and moreover, dissolves the porous resin layer and
makes plugging by dissolved one, in the case of laminating with the
porous resin layer.
[0124] The ionizing radiation-curable type resin used as an
adhesive in the present invention may include polymer having
radical polymeric double bonds such as relatively low molecular
weight polyester or polyether, (meth)acrylate such as acryl resin,
epoxy resin, or urethane resin, radical polymeric mono-functional
monomer or multi-functional monomer and if desired, a photo
polymerization initiator for polymeric cross-linking by means of
ultraviolet light. Any known ionizing radiation-curable type resin
may be used with equal success according to the present invention.
The solvent-free moisture-curable type polyurethane resin as
adhesive is favorable, but not limited to it. Examples as a source
of the moisture-curable polyurethane resin are included one-part
prepolymer produced by reaction between polyol such as polyether
polyol or polyester polyol and isocyanate, and two-part curable
adhesive of polyol and isocyanate.
[0125] The adhesive may preferably be applied to the tissue paper
while being heated to have a desired range of the viscosity by a
known manner such as, but nut limited to, roll coater, gravure,
gravure offset, or splay technique.
[0126] The amount of the solventless curable type adhesive is
preferably 0.05 to 1.0 g/m.sup.2 and more preferably 0.1 to 0.7
g/m.sup.2. If the amount is not greater than 0.05 g/m.sup.3, the
bonding strength will be declined. When exceeding 1.0 g/m.sup.2,
the bonding condition will hardly be ideal.
EXAMPLES
[0127] Some examples of the present invention will now be described
which are of no limitations.
Example 1
[0128] (Preparation of Tissue Paper used for Heat-Sensitive Stencil
Sheet)
[0129] A wet-type paper making method was performed to produce a
mixture paper of 10.0 g/m.sup.2 in the basis weight and 40.2 .mu.m
in the thickness from (80 parts by weight of) Manila hemp and (20
parts by weight of) polyester fiber at 0.4 denier. Using a sizing
press, the mixture paper was the impregnated with an emulsion water
solution of an ionizing radiation-curable resin material
(self-emulsifiable polyurethane acrylate, Beamset EM-02 by Arakawa
Chemical) to fabricate a tissue paper used for heat-sensitive
stencil sheet of the present invention coated with the resin at a
dry amount of 2.0 g/m.sup.2.
[0130] (Preparation of Heat-Sensitive Stencil Sheet)
[0131] The tissue paper used for heat-sensitive stencil sheet was
placed over a biaxially oriented polyester film of 1.5 .mu.m thick,
wound on the mirror surface of a roll with the film inside, and
exposed to 5 M rad. of electron beam to produce a combined web. The
combined web was then coated at the polyester film side with a 1 wt
% solution of water soluble silicon oil (FZ2101 by Nippon Unica) by
a gravure coating method and dried to have a heat-sensitive stencil
sheet of the present invention. Its evaluation result is shown in
Table 1.
Example 2
[0132]
1 Acetal resin (KS-1 by Sekisui Chemical) 2.5 Talc 0.8 Surface
active layer (SO15U by Nikko Chemical) 0.1 Surface active layer
(KF6012 by Shin-etsu Chemical) 0.1 Surface active layer (J711 by
Johnson) 0.2 Ethyl acetate 43.0
[0133] The above mixture was dissolved, dispersed, and gently added
with 20.0 parts by weight of water (HEC 1% solution) while stirred
to have a while emulsion coating. The coating was applied onto a
biaxially oriented polyester film of 1.5 .mu.m thick by a die
coating method so that its dry amount was 2.0 g/m.sup.3 which were
then dried and taken up as a combined web composed of the
thermoplastic resin film and the porous resin layer.
[0134] (Preparation of Heat-Sensitive Stencil Sheet)
[0135] The tissue paper used for heat-sensitive stencil sheet of
Example 1 was placed over the porous resin layer side of the above
combined web composed of the thermoplastic resin film and the
porous resin layer, wound on the mirror surface of a roll with the
film inside, and exposed to 5 M rad. of electron beam to produce
another combined web. The another combined web was then coated at
the polyester film side with a 1 wt % solution of water soluble
silicon oil (FZ2101 by Nippon Unica) by a gravure coating method
and dried to have a heat-sensitive stencil sheet of the present
invention. Its evaluation result is shown in Table 1.
Example 3
[0136] (Preparation of Tissue Paper used for Heat-Sensitive Stencil
Sheet)
[0137] A web-type paper making method was performed to produce a
polyester paper of 8.0 g/m.sup.2 in the basis weight and 32.0 .mu.m
in the thickness from (70 parts by weight of) polyester fiber at
1.0 denier and (30 parts by weight of) oriented polyester fiber at
0.4 denier which were heated to 120.degree. C. Using a sizing
press, the polyester paper was then impregnated with an emulsion
water solution of an ionizing radiation-curable resin material
(self-emulsifiable polyurethane acrylate, Beamset EM-90 by Arakawa
Chemical) to fabricate tissue paper used for heat-sensitive stencil
sheet of the present invention coated with the resin at a dry
amount of 0.8 g/m.sup.2.
[0138] (Preparation of Heat-Sensitive Stencil Sheet)
[0139] The tissue paper used for heat-sensitive stencil sheet was
coated at one side with a one-part urethane adhesive (Polyurethane
acrylate, Beamset 255 by Arakawa Chemical) at an amount of 0.4
g/m.sup.3 using a roll coater heated to 100.degree. C., placed over
a biaxially oriented polyester film of 1.5 .mu.m thick, wound on
the mirror surface of a roll with the film inside, and exposed to 5
Mrad of electron beam to produce a combined web. The viscosity of
the adhesive was about 1000 cps during the application. The
combined web was then coated at the polyester side with a 1 wt %
solution of water soluble silicon oil (FZ2101 by Nippon Unica) by a
gravure coating method and dried to have a heat-sensitive stencil
sheet of the present invention. Its evaluation result is shown in
Table 1.
Example 4
[0140] (Preparation of Heat-sensitive Stencil Sheet)
[0141] The tissue paper used for heat-sensitive stencil sheet of
Example 3 was coated at one side with an ionizing radiation-curable
type resin (Polyurethane acrylate, Beamset 502 H by Arakawa
Chemial) at an amount of 0.3 g/m.sup.2 using a roll coater heated
to 60.degree. C. placed over the porous resin layer side of the
combined web of Example 2 which was composed of the thermoplastic
resin film and the porous resin layer, wound on the mirror surface
of a roll with the film inside, and exposed to 5 M rad. of electron
beam to produce another combined web. The viscosity of the adhesive
was about 1500 Cps during the application. The another combined web
was then coated at the polyester film side with a 1 wt % solution
of water soluble silicon oil (FZ2101 by Nippon Unica) by a gravure
coating method and dried to have a heat-sensitive stencil sheet of
the present invention. Its evaluation result is shown in Table
1.
Example 5
[0142] (Preparation of Tissue Paper used for Heat-Sensitive Stencil
Sheet)
[0143] Using a combination wet-type paper making machine equipped
with a circular screen (for depositing a first layer) and a short
screen (for depositing a second layer), 7.5 g/m.sup.2 in the basis
weight of Manila hemp was produced as the first layer and 5.0
g/m.sup.2 in the basis weight of a combination of (60 parts by
weight of) sheathed polyester fiber at 1.0 denier and (40 parts by
weight of) polyester fiber at 0.2 denier was produced as the second
layer. The two layers were heated at 120.degree. C. from the
polyester fiber layer side to have a porous supporting web. Using a
sizing press, the supporting web was then impregnated with the
emulsion water solution of an ionizing radiation-curable resin
material (self-emulsifiable polyurethane acrylate, Beamset EM-92 by
Arakawa Chemical). After dried, the two layers were separate to
have tissue paper used for heat-sensitive stencil sheets of the
present invention. The resin amount was 1.5 g/m.sup.2 at the first
(Manila hemp) layer tissue paper used for heat-sensitive stencil
sheet and 0.3 g/m.sup.2 at the second (polyester fiber) layer
tissue paper used for heat-sensitive stencil sheet.
[0144] (Preparation of Heat-Sensitive Stencil Sheet)
[0145] The second (polyester fiber) layer tissue paper used for
heat-sensitive stencil sheet was coated at the first layer removed
side with an ionizing radiation-curable type resin (Polyurethane
acrylate, Beamset 502 H by Arakawa Chemical) at an amount of 0.3
g/m.sup.2 using a roll coater heated to 60.degree. C., placed over
the porous resin layer side of the combined web of Example 2 which
was composed of the thermoplastic resin film and the porous resin
layer, wound on the mirror surface of a roll with the film inside,
and exposed to 5 M rad. of electron beam to produce another
combined web. The viscosity of the adhesive was about 1500 cps
during the application. The another combined web was then coated at
the polyester film side with a 1 wt % solution of water soluble
silicon oil (FZ2101 by Nippon Unica) by a gravure coating method
and dried to have a heat-sensitive stencil sheet of the present
invention. Its evaluation result is shown in Table 1.
Example 6
[0146] (Preparation of Heat-Sensitive Stencil Sheet)
[0147] The first (Manila hemp) layer tissue paper used for
heat-sensitive stencil sheet of Example 5 was placed over the
porous resin layer side of the combined web of Example 2 which was
composed of the thermoplastic resin film and the porous resin
layer, wound on the mirror surface of a roll with the film inside,
and exposed to 5 M rad. of electron beam to produce another
combined web. The another combined web was then coated at the
polyester film side with a 1 wt % solution of water soluble silicon
oil (FZ2101 by Nippon Unica) by a gravure coating method and dried
to have a heat-sensitive stencil sheet of the present invention.
Its evaluation result is shown in Table 1.
Example 7
[0148] (Preparation of Tissue Paper used for Heat-Sensitive Stencil
Sheet)
[0149] Using a combination wet type paper making machine equipped
with a circular screen (for depositing a fret layer), a short
screen (for depositing a second layer), and a third screen (for
depositing a third layer), 6.0 g/m.sup.2 in the basis weight of (80
parts by weight of) sheathed polyester fiber at 1.0 denier and (20
parts by weight of) polyester fiber at 1.0 denier was produced as
the first and third layers and 3.0 g/m.sup.2 in the basis weight of
polyester fiber at 0.1 denier was produced as the second layer. The
two layer were heated at 120.degree. C., from both sides to have a
porous supporting web. Using a sizing press, the supporting web was
then impregnated with an emulsion water solution of an ionizing
radiation-curable resin material (self-emulsifiable polyurethane
acrylate, Beamset EM-92 by Arakawa Chemial). After dried, the web
was separated at the second layer into two tissue paper used for
heat-sensitive stencil sheets of the present invention. The resin
amount was 1.0 g/m.sup.2 at each the tissue paper used for
heat-sensitive stencil sheet.
[0150] (Preparation of Heat-Sensitive Stencil Sheet)
[0151] The above tissue paper used for heat-sensitive stencil sheet
was coated at the not-separated side with an ionizing
radiation-curable type resin (Polyurethane acrylate, Beamset 502 H
by Arakawa Chemical) at an amount of 0.3 g/m.sup.2 using a roll
coater heated to 60.degree. C. placed over a biaxially oriented
polyester film of 1.5 .mu.m thick, wound on the mirror surface of a
roll with the film inside, and exposed to 5 M rad. of electron beam
to produce a combined web. The combined web was then coated at the
polyester film side with a 1 wt % solution of water soluble silicon
oil (FZ2101 by Nippon Unica) by a gravure coating method and dried
to have a heat-sensitive stencil sheet of the present invention.
Its evaluation result is shown in Table 1.
Example 8
[0152] (Preparation of Heat-Sensitive Stencil Sheet)
[0153] The same manner as of Example 7 was performed to fabricate a
heat-sensitive stencil sheet of the present invention, except that
the combined web of Example 2 which was composed of the
thermoplastic resin film and the porous resin layer was employed.
Its evaluation result is shown in Table 1.
Comparison 1
[0154] (Preparation of Tissue Paper used for Heat-Sensitive
Heat-Sensitive Stencil Sheet Sheet)
[0155] A wet-paper making method was performed to produce a mixture
paper of 10.0 g/m.sup.2 in the basis weight and 40.2 .mu.m in the
thickness from (80 parts by weight of) Manila hemp and (20 parts by
weight of) polyester fiber at 0.4 denier. Using a gravure coating
method, the mixture paper was then impregnated with an emulsion
water solution of urethane resin (water-dispersion polyurethane
resin, Adecabontitor HUX-401 by Asahi Denka) to fabricate a
conventional tissue paper used for heat-sensitive stencil sheet
coated with the resin at a dry amount of 1.0 g/m.sup.3.
[0156] (Preparation of Heat-Sensitive Stencil Sheet)
[0157] The tissue paper used for heat-sensitive stencil sheet was
coated at one side with an ionizing radiation-curable type resin
(polyurethane acrylate resin, Beamset 502 H by Arakawa Chemical) at
an amount of 0.3 g/m.sup.2 using a roll coater heated to 60.degree.
C., placed over a biaxially oriented polyester film of 1.5 .mu.m
thick, wound on the mirror surface of a roll with the film inside,
and exposed to 5 M rad. of electron beam to produce a combined web.
The combined web was then coated at the polyester film side with a
1 wt % solution of water soluble silicon oil (FZ2101 by Nippon
Unica) by a gravure coating method and dried to have a conventional
heat-sensitive stencil sheet. Its evaluation result is shown in
Table 1.
Comparison 2
[0158] (Preparation of Tissue Paper used for Heat-Sensitive Stencil
Sheet)
[0159] A wet-type paper making method was performed to produce a
conventional tissue paper used for heat-sensitive stencil sheet of
10.0 g/m.sup.2 in the basis weight and 40.2 .mu.m in the thickness
from (80 parts by weight of) Manila hemp and (20 parts by weight
of) polyester fiber at 0.4 denier.
[0160] (Preparation of Heat-sensitive Stencil Sheet)
[0161] The tissue paper used for heat-sensitive stencil sheet was
laced over a biaxially oriented polyester film of 1.5 .mu.m thick,
coated at the tissue side with an ionizing radiation-curable type
resin (polyurethane acrylate resin, Beamset 502 H by Arakawa
Chemical) at a dry amount of 1.0 g/m.sup.2 using a gravure coating
method, dried, wound on the mirror surface of a roll with the film
inside, and exposed to 5 M rad. of electron beam to produce a
combined web. The combined web was then coated at the polyester
film side with a 1 wt % solution of water soluble silicon oil
(FZ2101 by Nippon Unica) by a gravure coating method and dried to
have a conventional heat-sensitive stencil sheet. Its evaluation
result is shown in Table 1.
Comparison 3
[0162] (Preparation of Tissue Paper used for Heat-Sensitive Stencil
Sheet)
[0163] A wet-type paper making method was performed to produce a
mixture of (70 parts by weight of) sheathed polyester fiber at 1.0
denier and (30 parts by weight of) oriented polyester fiber at 0.4
denier. The mixture was heated at 120.degree. C. to fabricate a
conventional tissue paper used for heat-sensitive stencil sheet of
8.0 g/m.sup.2 in the basis weight and 32.0 .mu.m in the
thickness.
[0164] (Preparation of Heat-Sensitive Stencil Sheet)
[0165] The tissue paper used for heat-sensitive stencil sheet was
placed over a biaxially oriented polyester of 1.5 .mu.m thick,
coated at the tissue paper side with a water/alcohol solution of an
ionizing radiation-curable type resin (self-emulsified polyurethane
acrylate resin, Beamset EM-92 by Arakawa Chemical) at a dry amount
of 1.0 g/m.sup.2 using a gravure coating method, wound on the
mirror surface of a roll with the the inside, and exposed to 5 M
rad. of electron beam to produce a combined web. The combined web
was then coated at the polyester film side with a 1 wt % solution
of water soluble silicon oil (FZ2101 by Nippon Unica) by a gravure
coating method and dried to have a conventional heat-sensitive
stencil sheet. Its evaluation result shown in Table 1.
Comparison 4
[0166] (Preparation of Tissue Paper used for Heat-Sensitive Stencil
Sheet)
[0167] Using a combination wet-type paper making machine equipped
with a circular screen (for depositing a first layer) and a short
screen (for depositing a second layer), 7.5 g/m.sup.2 in the basis
weight of Manila hemp was produced as the first layer and 5.0
g/m.sup.2 in the basis weight of a combination of (60 parts by
weight of) sheathed polyester fiber at 1.0 denier and (40 parts by
weight of) polyester fiber at 0.2 denier was produced as the second
layer. The two layers were heated at 120.degree. C. from the
polyester fiber layer side to have a porous supporting web. The two
layers of the web were separated to have conventional tissue paper
used for heat-sensitive stencil sheets.
[0168] (Preparation of Heat-Sensitive Stencil Sheet)
[0169] The second (polyester fiber) layer tissue paper used for
heat-sensitive stencil sheet was coated at the not-separated side
with an ionizing radiation-curable type resin (Polyurethane
acrylate, Beamset 502 H by Arakawa Chemical) at an amount of 0.3
g/m.sup.2 using a roll coater heated to 60.degree. C., placed over
a biaxially oriented polyester film of 1.5 .mu.m thick, wound on
the mirror surface of a roll with the film inside, and exposed to 5
M rad of electron beam to produce a combined web. The combined web
was then coated at the polyester film side with a 1 wt % solution
of water soluble silicon oil (FZ2101 by Nippon Unica) by a gravure
coating method and dried to have a conventional heat-sensitive
stencil sheet. Its evaluation result is shown in Table 1.
Evaluation for Characteristics
[0170] Each of the masters was loaded to a commercial printer,
Preport VT3950 by Ricoh, (at a thermal head solution of 400 dpi),
processed by a thermal head perforation technique, and subjected to
a printing action with an original having a solid black portion, 50
mm.times.50 mm and 6-point letters. The printing was conducted at a
standard speed.
[0171] (1) Removal of Fibers
[0172] After the printing action was repeated 10 times, resultant
prints were visually examined for attachment of fibers on the
platen roll. The evaluation was graded B when no fiber appeared, C
when a few fibers appeared, and D when fibers were attached.
[0173] (2) Sharpness of fine lines
[0174] The reproduction of 6-point letters in prints was examined
and graded A when the letters appeared sharp with no loss, B when
legible with some loss in the letter, D when hardly legible with
loss in the letters, and C when least acceptable between B and
D.
[0175] (3) Print solidness
[0176] Resultant prints were visually examined for solid black
print and graded A when (printing ink) uniformly solid without
blanks, B when minimum blanks appeared, D when blanks were highly
noticeable, and C when least acceptable between B and D.
2 TABLE 1-1 coating tissue paper used for heat- weight of sensitive
stencil sheet resin impregnated porous basis thick- coating resin
layer weight ness weight (g/m.sup.2) type (g/m.sup.2) (.mu.m) resin
type (g/m.sup.2) Ex. 1 -- mixture 10.0 40.2 EM92 2.0 paper Ex. 2
2.0 mixture 10.0 40.2 EM92 2.0 paper Ex. 3 -- polyester 8.0 32.0
EM90 0.8 paper Ex. 4 2.0 polyester 8.0 32.0 EM92 0.8 paper obtained
by separation Ex. 5 2.0 polyester 5.0 25.0 EM92 0.3 paper obtained
by separation Ex. 6 2.0 natural fiber 7.5 35.4 EM92 1.5 paper
obtained by separation Ex. 7 -- polyester 7.5 30.1 EM02 1.0 paper
obtained by separation Ex. 8 2.0 polyester 7.5 30.1 EM92 1.0 paper
obtained by separation Com. -- mixture 10.0 40.2 Polyurethane 1.0
Ex. 1 paper HUX-401 Com. -- mixture 10.0 40.2 -- -- Ex. 2 paper
Com. -- polyester 8.0 32.0 -- -- Ex. 3 paper Com. -- polyester 5.0
25.0 -- -- Ex. 4 paper obtained by separation
[0177]
3 TABLE 1-2 evaluation result of tissue paper used for adhesive
heat-sensitive stencil sheet coating surface removal print resin
weight smoothness of sharpness solid- type (g/m.sup.2) of film
fibers of fine lines ness Ex. 1 -- 2.0 excellent B B B Ex. 2 -- 2.0
excellent H A B Ex. 3 Beamset 0.8 excellent B H B 255 Ex. 4 Beamset
0.8 excellent B A A 502H Ex. 5 Beamset 0.3 excellent B A A 502H Ex.
6 -- 1.5 excellent B A B Ex. 7 Beamset 1.0 excellent B B B 502H Ex.
8 Beamset 1.0 excellent B A A 502H Com. Beamset 1.0 many small B D
D Ex. 1 502H wrinkles Com. Beamset -- excellent B D C Ex. 2 502H
Com. -- -- excellent B C C Ex. 3 Com. Beamset -- many small D D B
Ex. 4 502H wrinkles
[0178] As apparent from the foregoing detailed and specified
description, the present invention allows the tissue paper used for
heat-sensitive stencil sheet to be impregnated with an ionizing
radiation-curable type resin material for ease of bonding to one
side of a thermoplastic resin film or a porous resin layer coated
side of a porous resin layer coated thermoplastic resin film.
Accordingly, the tissue when stressed by tension during the
lamination can be cured to ensure the smoothness of the film
surface hence significantly improving the productivity. Also, the
heat-sensitive stencil sheet according to the present invention is
provided satisfying the primary requirements; (1) the
passing-through of printing ink, (2) ease of the perforation, (3)
no removal of fibers, (4) the resistance to printing action, and
(5) the productivity.
* * * * *