U.S. patent application number 10/217432 was filed with the patent office on 2003-05-29 for ink jet material and process for producing same.
This patent application is currently assigned to Oji Paper Co., Ltd.. Invention is credited to Higuchi, Tadashi, Kubota, Masami, Liu, Bo, Mukoyoshi, Shun-Ichiro, Nemoto, Hiroyuki.
Application Number | 20030099816 10/217432 |
Document ID | / |
Family ID | 27526091 |
Filed Date | 2003-05-29 |
United States Patent
Application |
20030099816 |
Kind Code |
A1 |
Liu, Bo ; et al. |
May 29, 2003 |
Ink jet material and process for producing same
Abstract
An ink jet recording material having a high gloss and capable of
recording thereon ink images having high color density and clarity,
has an ink-receiving layer formed on a substrate and including a
binder and secondary particle having an average size of 10 to 300
nm and including a plurality of primary particles of silica
prepared by wet method and/or aluminosilicate agglomerated with
each other without binder, and can be produced by forming the
ink-receiving layer on a shaping base, bonding the substrate to the
ink-receiving layer on the shaping base and separating the
resultant laminate from the shaping base.
Inventors: |
Liu, Bo; (Chiba-shi, JP)
; Kubota, Masami; (Chiba-shi, JP) ; Nemoto,
Hiroyuki; (Ichihara-shi, JP) ; Mukoyoshi,
Shun-Ichiro; (Ichikawa-shi, JP) ; Higuchi,
Tadashi; (US) |
Correspondence
Address: |
ARENT FOX KINTNER PLOTKIN & KAHN
1050 CONNECTICUT AVENUE, N.W.
SUITE 400
WASHINGTON
DC
20036
US
|
Assignee: |
Oji Paper Co., Ltd.
|
Family ID: |
27526091 |
Appl. No.: |
10/217432 |
Filed: |
August 14, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10217432 |
Aug 14, 2002 |
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09567900 |
May 10, 2000 |
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09567900 |
May 10, 2000 |
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08842043 |
Apr 23, 1997 |
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Current U.S.
Class: |
428/195.1 |
Current CPC
Class: |
B41M 5/5218 20130101;
B32B 27/20 20130101; Y10T 428/24802 20150115 |
Class at
Publication: |
428/195 |
International
Class: |
B32B 003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 24, 1996 |
JP |
8-102494 |
Jun 24, 1996 |
JP |
8-162818 |
Sep 19, 1996 |
JP |
8-248267 |
Sep 19, 1996 |
JP |
8-248268 |
Claims
We claim:
1. An ink jet recording material comprising: a substrate; and an
ink-receiving layer formed on at least one surface of the
substrate, wherein the ink-receiving layer comprises a binder, and
a plurality of secondary particles, wherein the secondary particles
have an average secondary particle size of 10 to 300 nm, each of
the secondary particles consisting essentially of a plurality of
primary particles of at least one member selected from the group
consisting of silica prepared by wet method, which silica will be
referred to as wet method silica hereinafter, and aluminosilicate,
and wherein the primary particles are agglomerated with each other
to form the secondary particles by an attraction force including
hydrogen bonding force between silanol groups located on the
surfaces of the primary particles and van der Waals force between
the primary particles, in each of the secondary particles, pores
being formed between the agglomerated primary particles.
2. The ink jet recording material as claimed in claim 1, wherein
the binder for the ink-receiving layer comprises water-soluble
resin.
3. The ink jet recording material as claimed in claim 1, wherein
the secondary particles each consist essentially of a plurality of
silica primary particles are those prepared from agglomerated
silica particles by a breaking down method by which the average
secondary particle size is adjusted to 10 to 300 nm.
4. The ink jet recording material as claimed in claim 1, wherein
the primary particles of wet method silica and aluminosilicate have
an average primary particle size of 3 to 40 nm.
5. The ink jet recording material as claimed in claim 1, wherein
the ink-receiving layer has a plurality of pores formed therein and
exhibits a pore radius distribution curve having a peak
corresponding to a pore radius of about 40 nm or less.
6. The ink jet recording material as claimed in claim 5, wherein at
least one additional ink-absorbent layer comprising a binder resin
and a plurality of pigment particles, is formed between the
substrate and the ink-receiving layer.
7. The ink jet recording material as claimed in claim 5, wherein
the binder for the additional ink-absorbent layer comprises a
water-soluble resin.
8. The ink jet recording material as claimed in claim 5, wherein
the secondary particles are each composed essentially of a
plurality of primary particles having an average primary particle
size of 3 to 40 nm and agglomerated with each other, and have an
average secondary particle size of 10 to 150 nm.
9. The ink jet recording material as claimed in claim 2 or 7,
wherein the water-soluble resin comprises a polyvinyl alcohol
having an degree of polymerization of 2,000 or more.
10. The ink jet recording material as claimed in claim 2 or 7,
wherein the water-soluble resin comprises a polyvinyl alcohol
having a degree of saponification of 95% or more.
11. The ink jet recording material as claimed in claim 5, wherein
the ink-receiving layer has a plurality of pores formed therein,
and exhibits an integrated pore volume of all the pores of 0.6 ml/g
or more, and a total volume of the pores with a pore radius of 3 to
20 nm of 0.3 ml/g or more.
12. The ink jet recording material as claimed in claim 1, wherein
at least one additional ink-absorbent layer, comprising a binder
resin and a plurality of pigment particles, is formed between the
substrate and the ink-receiving layer.
13. The ink jet recording material as claimed in claim 1, wherein
the ink receiving layer has a haze value of 4 to 65%.
14. The ink receiving layer as claimed in claim 13, wherein the
binder for the ink-receiving layer comprises a water-soluble
resin.
15. The ink jet recording material as claimed in claim 13, wherein
the secondary particles are each composed essentially of a
plurality of primary particles having an average primary particle
size of 3 to 40 nm and agglomerated with each other, and have an
average secondary particle size of 10 to 200 nm.
16. The ink jet recording material as claimed in claim 13, wherein
at least one additional ink-absorbent layer comprising a binder
resin and a plurality of pigment particles is formed between the
substrate and the ink receiving layer.
17. The ink jet recording material as claimed in claim 1, wherein
the substrate is transparent.
18. The ink jet recording material as claimed in claim 17, wherein
the ink-receiving layer formed on the transparent substrate surface
comprises the secondary particles having an average secondary
particle size of 10 to 100 nm and formed from the primary particles
of at least one member selected from the group consisting of wet
method silica and aluminosilicate, having an average primary
particle size of 3 to 30 nm.
19. The ink jet recording material as claimed in claim 17 or 18,
having a haze value of 20% or less.
20. The ink jet recording material as claimed in claim 1, wherein
the substrate is bonded to the ink-receiving layer through an
intermediate layer comprising a member selected from the group
consisting of bonding materials and adhesive materials.
21. The ink jet recording material as claimed in claim 1, wherein
the primary particles for the secondary particles for the
ink-receiving layer are those of the wet method silica.
22. The ink jet recording material as claimed in claim 1, wherein
the primary particles are agglomerated with each other to form the
secondary particles without any binder.
23. A process for producing an ink jet recording material,
comprising the steps of: forming an ink-receiving layer comprising
a binder, and a plurality of secondary particles having an average
secondary particle size of 500 nm or less and each comprising a
plurality of primary particles of at least one member selected from
the group consisting of silica and aluminosilicate, and
agglomerated with each other to form the secondary particles, on a
surface of a shaping base; bonding the substrate to the
ink-receiving layer provided on the shaping base to form a
laminate; and separating the resultant laminate from the shaping
base.
24. The process as claimed in claim 23, wherein the secondary
particles have an average secondary particle size of 10 to 300
nm.
25. The process as claimed in claim 23, wherein the primary
particles of silica and aluminosilicate have an average primary
particle size of 3 to 40 nm.
26. The process as claimed in claim 23, wherein the substrate is
bonded to the ink-receiving layer provided on the shaping base
through a member selected from the group consisting of bonding
materials and adhesive materials.
27. The process as claimed in claim 23, wherein the step of bonding
the substrate to the ink receiving layer is carried out by wetting
the surface of the ink receiving layer with water or water vapor,
and then press-bonding the substrate to the surface-wetted
receiving layer to provide a laminate.
28. The process as claimed in claim 23, further comprising the step
of forming an additional ink-absorbent layer comprising a binder
and pigment particles on a surface of the substrate before the
bonding step, the additional ink-absorbing layer provided on the
substrate being bonded to the ink-receiving layer provided on the
shaping base.
29. The process as claimed in claim 28, wherein the bonding step is
carried out by wetting at least one of the ink-receiving layer
provided on the shaping base and the additional ink-absorbent layer
provided on the substrate with water or water vapor, and then
press-bonding the additional ink-absorbent layer on the substrate
and the ink-receiving layer on the shaping base, to provide a
laminate.
30. The process as claimed in claim 23, further comprising the step
of forming an additional ink-absorbent layer comprising a binder
and pigment particles on a surface of the ink receiving layer
before the bonding step, the additional ink-absorbing layer
provided on the ink receiving layer being bonded to the
substrate.
31. The process as claimed in claim 30, wherein the bonding step is
carried out by wetting the additional ink-absorbent layer provided
on the ink receiving layer with water or water vapor, and then
press-bonding the additional ink-absorbent layer and the
ink-receiving layer on the shaping base, to provide a laminate.
32. The process as claimed in claim 23, wherein the binder for the
ink-receiving layer comprises a water-soluble resin.
Description
[0001] This application is a continuation-in-part application of
Ser. No. 08/842,043 filed on Apr. 23, 1997, entitled INK JET
RECORDING MATERIAL AND PROCESS FOR. PRODUCING SAME.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an, ink jet recording
material and a process for producing the same. More particularly,
the present invention relates to an ink jet recording material
having excellent gloss, ink-receiving property, water-resistance,
weather resistance and being capable of recording ink images with
excellent color density and brightness and clarity, and a process
for producing the same.
[0004] 2. Description of the Related Art
[0005] The ink jet recording system is an ink image recording
system wherein ink droplets are jetted through an ink-jetting
nozzle toward a recording material and jetted ink droplets are
absorbed in and fixed on the recording material, to form ink
images. This ink jet recording system is advantageous in that full
colored images can be easily formed and the printing noise is
low.
[0006] The ink usable for the ink jet recording system contains a
large amount of a solvent in which a coloring material is dissolved
or dispersed and thus, to obtain a high color density of the
recorded ink images, a large amount of the ink must be absorbed in
the recording material. In the complete absorption of the ink
droplets reached the recording material, a certain length of time
is necessary. This feature of the ink jet recording system causes
such a disadvantage that when the ink droplets are continuously
jetted imagewise to form ink dots on the recording material
surface, sometimes the ink droplets reach a target dot before an
ink dot adjacent to the target dot has been completely absorbed in
the recording material, and the target ink dot is connected to the
adjacent ink dot so that the resultant ink image becomes
unclear.
[0007] Accordingly, if the recording material for the ink jet
recording system is to have such an advantage that the ink dots
formed thereon have high color density and brightness and a high
clarity, the ink droplets must be rapidly absorbed therein and even
if the ink dots are overlapped on each other, substantially no
blotting of the ink may occur.
[0008] When a coated paper sheet is used as a substrate for the ink
jet recording material, at least one ink-receiving layer comprising
a porous pigment is formed on the coated paper sheet to control the
color brightness and sharpness of the ink images from which the
image quality is established and to enhance the
color-reproducibility and image-reproductivity. For example,
Japanese Unexamined Patent Publication No. 62-111,782, No.
63-13,776 and No. 63-104,878 disclose an ink jet recording sheet
having an ink-receiving layer containing primary or secondary
pigment particles (usually, silica or alumina particles) having
fine pores, and a binder. Also, Japanese Examined Patent
Publication No. 63-22,977 discloses an ink jet recording sheet
which has an ink-receiving layer including an uppermost layer
provided with pores having a peak size of from 0.2 to 10 .mu.m, and
is capable of receiving an absorbed ink in voids having a size of
0.05 .mu.m or less, and of forming ink images with a high
quality.
[0009] Currently, due to the rapid spread of ink jet printers,
various ink jet prints with a high gloss similar to that of
photographic prints are demanded for publications and packing paper
sheets. Particularly, in colored prints, film type or coated sheet
type ink jet recording sheets which have high ink-absorbing and
fixing rates and a high ink absorption are in great demand. To
provide the above-mentioned ink-receiving layer having an increased
porosity, it is necessary to use pigment particles having an
increased particle size in the .mu.m order or to utilize secondary
particles of pigment. When the size of the pigment particles is
increased, the resultant ink-receiving layer exhibits a decreased
smoothness and a reduced light transmission. Namely, the resultant
ink-receiving layer is opaque and has a poor gloss.
[0010] Various types of ink jet recording sheets having an
ink-receiving layer containing a resin capable of dissolving
therein the ink and of swelling by the ink are practically used.
These types of ink jet recording sheets have an enhanced gloss.
However, they are disadvantageous in that the resultant
ink-receiving layer exhibits a low ink-drying rate and
unsatisfactory resistance to moisture and water.
[0011] To enhance the smoothness and gloss of the ink-receiving
layer, it has been attempted to form the ink-receiving layer in a
two or more layered structure wherein an uppermost layer has a high
gloss. This type of ink jet recording sheet is disclosed in, for
example, Japanese Unexamined Patent Publications No. 3-215,080, No.
3-256,785, No. 7-89,220, 7-101,142 and 7-117,335. In this type of
ink jet recording sheet, colloidal particles or a complex of
colloidal particles are commonly used as a principal component of
the high gloss layer. This type of high gloss layer is formed from
the colloidal particles or complex thereof dispersed in a binder
comprising a polymer latex, to establish a satisfactory
transparency and ink-absorption. When the polymer latex is used as
a binder, a plurality of small cracks are formed in the resultant
coating layer. The small cracks are contributory to enhancing the
ink-absorption of the ink-receiving layer. However, the small
cracks cause the resultant ink dots formed on the cracked
ink-receiving layer to have jagged circumferences significantly
different from round circumferences, and thus the resultant ink
images to exhibit reduced clarity and sharpness. Also, the small
cracks cause the printed ink to spread on the ink-receiving layer
and thus the ink dots to be enlarged. When the ink dots are formed
in a usual density of the level of 360 dots per inch.times.360 dots
per inch (dpi), the spread of the ink dots due to the small cracks
of the ink-receiving layer does not cause any problems. However, if
the ink dots are formed in a high density of the level of 720 dots
per inch.times.720 dots per inch or more, the spread of the ink
causes the spread ink dots to be connected to each other and thus
the resultant ink images exhibits significantly reduced clarity and
sharpness. Also, the colloidal particles in the uppermost
high-gloss layer are primary particles and thus have substantially
no fine pores capable of receiving the ink therein. Therefore, the
ink is absorbed in the ink-fixing layer formed under the uppermost
high-gloss layer. In the above-mentioned multi-layered
ink-receiving layer, an ink-fixing layer is formed under the high
gloss layer, and the thickness of the ink-fixing layer is larger
than that of the high gloss layer. Also, the ink-fixing layer
contains secondary particles of a pigment having a particle size in
a .mu.m order, the resultant multi-layered ink-receiving layer
exhibits a significantly reduced transparency and thus the ink
images fixed in the ink-receiving layer exhibit an unsatisfactory
color density. Especially, this type of ink-receiving layer
exhibits a reduced light reflection and thus an insufficient
gloss.
[0012] To prevent the formation of the small cracks in the
ink-receiving layer, Japanese Unexamined Patent Publication No.
7-117,334 provides an ink-receiving layer formed from a composition
comprising pigment particles with a particle size of 0.1 .mu.m or
less and a polyvinyl alcohol with a degree of polymerization of
4,000 or more. The pigment particles are selected from primary
pigment particles for example, colloidal silica or alumina sol.
Therefore, in the resultant ink-receiving layer, the ink absorption
and the transparency are unbalanced. Namely, since the pigment
primary particles per se have no ink-absorption, the ink is
absorbed in the gaps between the pigment primary particles. The
gaps between the pigment primary particles in the ink-receiving
layer are filled by a film-forming binder which is necessary to
bond the pigment particles and to form an ink receiving layer.
Therefore, the binder-filled gaps between the pigment particles
exhibit a low ink absorption. To completely absorb a large amount
of the ink, the ink-receiving layer must be formed in a large
thickness. The ink-receiving layer with a large thickness easily
forms small cracks. Also, to obtain an ink-receiving layer having a
high transparency, the pigment primary particles must be selected
from those having a small particle size.
[0013] The smaller the pigment primary particle size, the lower the
ink-absorbing rate of the resultant ink-receiving layer. However,
the larger the pigment primary particle size, the lower the
transparency of the resultant ink-receiving layer, and the lower
the color density of the printed ink images.
[0014] Japanese Unexamined Patent Publication No. 2-276,670
discloses an ink-receiving layer for an ink jet recording material.
The ink-receiving layer is formed from a mixture of pseudoboehmite
and a binder and has a plurality of pores having a radius of 40 to
100 angstrom (4 to 10 nm) and a total volume of 0.1 to 0.4 ml/g.
The pseudoboehmite particles affect the hue of a certain type of
inks which are affected by alumina. Accordingly, the
pseudoboehmite-containing ink-receiving layer is unsuitable for the
above-mentioned inks, for example, Acid Red 52 (food red dye No.
106). Also, the pseudoboehmite has a disadvantage in that it per se
is yellowed with a lapse of time. Further, the pseudoboehmite is
expensive and thus is difficult to use in practice. Furthermore,
the pseudoboehmite particles are colloidal primary particles having
a poor ink absorption and thus the resultant ink-receiving layer
has an insufficient total pore volume and exhibits an
unsatisfactory ink-absorbing rate and ink-absorption capacity.
[0015] Japanese Unexamined Patent Publications No. 5-32,037 and No.
6-199,034 disclose an ink jet recording material having an
ink-receiving layer which contains agglomerated secondary particles
of pseudoboehmite with a particle size of 100 to 500 nm and is
provided with pores having a radius controlled to 30 to 100
angstrom (3 to 10 nm). However, this ink-receiving layer contains
the pseudoboehmite particles and thus can not be released from the
disadvantages derived from the pseudoboehmite particles. Namely,
although the agglomerated secondary particles of pseudoboehmite are
contributory to enhance the ink absorption of the resultant
ink-receiving layer to a certain extent, the total pore volume of
the ink-receiving layer containing the agglomerated secondary
particles of pseudoboehmite is not sufficiently large and thus when
the ink dots are formed in a high density of 720 dip.times.720 dpi
or more, the ink-receiving layer does not completely absorb the ink
at a satisfactory ink-absorbing rate.
[0016] Japanese Unexamined Patent Publication No. 7-117,335
discloses an ink jet recording material having an ink-receiving
layer having high smoothness and gloss. This ink-receiving layer is
formed in a multi-layered structure and has an uppermost gloss
layer comprising, as a principal component, colloidal particles or
composite colloidal particles, and laminated on an ink-fixing
layer. The uppermost gloss layer is formed by pressing the
uppermost layer in a wetted condition against a mirror-finished
perperal surface of a shaping roll. However, the uppermost layer
laminated on the ink-fixing layer easily sinks into the ink-fixing
layer upon pressing and thus is difficult to sufficiently smooth by
the mirror surface-transfer method. Accordingly, to enhance the
mirror surface-transfer effect onto the uppermost layer, a polymer
latex is used as a binder for the formation of the uppermost gloss
layer. The use of the polymer latex causes the resultant uppermost
gloss layer to be easily and finely cracked. The fine cracks
contribute to enhancing the ink absorption rate in the uppermost
gloss layer. However, the fine cracks also cause the resultant
uppermost gloss layer to exhibit a reduced gloss and the ink dots
formed on the uppermost gloss layer to have jagged circumferences
and to be easily connected to each other. These features of the ink
dots result in reduced clarity and sharpness of the printed ink
images.
[0017] Further, in the above-mentioned ink jet recording material,
since the uppermost layer of the ink-receiving layer is smoothed by
a mirror-finished surface, and then dried, the substrate must be an
air-permeable sheet, for example, a paper sheet. A non-permeable,
high smoothness sheet, for example, a plastic film or a laminate,
cannot be used as the substrate. When a paper sheet having a rough
surface is used as a substrate, the resultant ink-receiving layer
has a rough surface derived from the paper sheet surface. Also,
when the recording sheet is dried water vapor permeates through the
ink-receiving layer and forms pinholes in the ink-receiving layer.
Therefore, the ink-receiving layer having a high gloss similar to
that of photographic printing sheets is difficult to obtain.
[0018] To solve the above-mentioned problems, the inventors of the
present invention have provided an ink jet recording material
produced by forming an ink-receiving layer on a surface of a
shaping base; bonding a substrate to the ink-receiving layer formed
on the shaping base through an intermediate layer comprising a
bonding material or an adhesive material; and separating the
resultant laminate from the shaping base. In this type of ink jet
recording material, a water-soluble resin can be used as a binder
of the ink-receiving layer, the resultant ink dots on the
ink-receiving layer is in the form of a true circle and the
ink-receiving layer exhibits a high smoothness, a high ink
absorption and a high gloss.
[0019] However, where the ink-receiving layer is formed in two or
more-layered structure on the shaping base surface, a first layer
(corresponding to an porous uppermost layer of the resultant ink
jet recording is formed on the sheet) shaping base surface and then
second, third and other layers are successively formed on the
porous uppermost layer. In this case, pores or voids may be formed
in the surface portions of the second, third or other layers, and
may be retained even after the resultant multi-layered
ink-receiving layer is transferred from the shaping base to the
substrate surface. Also, when the coating liquids for the second,
third and other layers are successively coated on the uppermost
layer, the binder contained in those layers may diffuse into the
first layer (porous uppermost layer) so as to change the
ink-absorbing property of the first layer (porous uppermost layer).
Further, as the amounts of the second, third and other layers are
increased, the resultant multi-layered ink-receiving layer may
exhibit a poor resistance to crack-formation.
[0020] U.S. Pat. No. 5,612,281 for Kobayashi et al discloses a
recording sheet for ink jet recording having a transparent support
and transparent colorant-receptive layer having a three dimensional
network structure formed from silicic anhydride particles and a
water-soluble resin. The coating solution for the
colorant-receptive layer is prepared by, for example, by adding
silica fine particles having an average primary particle size
(diameter) of not more than 10 nm to water, dispersing the fine
silica particles by using a high speed rotary wet colloid mill,
adding, to the resultant aqueous fine silica dispersion, an aqueous
polyvinyl alcohol solution and adjusting the pH of the resultant
aqueous dispersion to 4.5, to obtain a homogeneous sol. The coating
solution is coated on the transparent support and dried to provide
the colorant-receptive layer. When the coating solution layer is
dried on the transparent support and reaches a gelation
concentration through the evaporation of water, a wet gel is formed
and, as the drying further progresses, a porous xerogel is formed
to obtain a colorant receptive layer. In the resultant colorant
receptive layer, the fine silica anhydride particles having a
primary particle size of not more than 10 nm are adhered to each
other through the polyvinyl alcohol binder to form a network
structure, but not secondary particles each consisting of a
plurality of primary particles agglomerated with each other, of the
fine silica particles. Thus, the colorant receptive layer has a
relatively high density and exhibits a poor ink absorbing property.
The silica really disclosed in the U.S. patent is only dry method
silica (dry process silica). The dry method silica causes the
resultant ink-receiving layer to exhibit an ink absorbing property
lower than that of the wet method silica (wet process silica).
SUMMARY OF THE INVENTION
[0021] An object of the present invention is to provide an ink jet
recording material having a high gloss, a high resistance to
weathering and a high resistance to water and capable of recording
ink images having excellent clarity, and sharpness and satisfactory
color density, brightness and brilliancy.
[0022] The above-mentioned object can be attained by the ink jet
recording material of the present invention which comprises:
[0023] a substrate; and
[0024] an ink-receiving layer formed on at least one surface of the
substrate, wherein said ink-receiving layer comprises a binder, and
a plurality of secondary particles, wherein said secondary
particles have an average secondary particle size of 10 to 300 nm,
each of said secondary particles consisting essentially of a
plurality of primary particles of at least one member selected from
the group consisting of silica prepared by wet method, which silica
will be referred to as wet method silica hereinafter, and
aluminosilicate, and wherein said primary particles are
agglomerated with each other to form said secondary particles
without any binder, in each of the secondary particles, pores being
formed between the agglomerated primary particles.
[0025] In an embodiment of the ink jet recording material of the
present invention, the ink-receiving layer has a haze value of 4 to
65%.
[0026] In another embodiment of the ink jet recording material of
the present invention, the ink-receiving layer has a plurality of
pores formed therein and exhibits a pore radius distribution curve
having a peak corresponding to a pore radius of about 40 nm or
less.
[0027] The process of the present invention for producing the ink
jet recording material comprises the steps of:
[0028] forming an ink-receiving layer comprising a binder, and a
plurality of secondary particles, having an average secondary
particle size of 500 nm or less and each comprising a plurality of
primary particles of at least one member selected from the group
consisting of silica and aluminosilicate, and agglomerated with
each other to form the secondary particles, on a surface of a
shaping base;
[0029] bonding the substrate to the ink-receiving layer provided on
the shaping base to form a laminate; and
[0030] separating the resultant laminate from the shaping base.
BRIEF DESCRIPTION OF THE DRAWING
[0031] FIG. 1 is a graph showing a pore radius distribution curve
and a cumulative pore volume curve of all the pores, of the
ink-receiving layer of the ink jet recording sheet of Example 14 in
accordance with the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0032] In the ink jet recording material of the present invention,
an ink-receiving layer is laminated on at least one surface of a
substrate. The ink-receiving layer comprises a binder matrix and a
plurality of specific pigment particles dispersed in the binder
matrix. The specific pigment particles for the present invention
are secondary particles each comprising a plurality of primary
particles of at least one member selected from the group consisting
of silica and aluminosilicate, and agglomerated with each other to
form the secondary particles having an average secondary particle
size of 10 to 300 nm.
[0033] A conventional silica pigment is in the form of a powder
consisting of a plurality of particles having a particle size of
several .mu.m, and thus exhibits a high ink absorption. However,
this type of conventional silica pigment causes a resultant coating
layer to exhibit a reduced transparency or to be opaque, and thus
is unsuitable as a pigment for an ink-receiving layer of an ink jet
recording material which is required to be capable of recording ink
images having an enhanced color density and a high gloss. Also, the
conventional silica pigment particles have a large particle size
and thus the resultant ink-receiving layer has a rough touch and is
difficult to fully smooth.
[0034] The inventors of the present invention have studied to solve
the above-mentioned problems of the conventional silica pigment and
found that the above-mentioned problems can be solved by using, as
a pigment, secondary agglomeration particles comprising a plurality
of primary particles of at least one member selected from silica
and aluminosilicate, and agglomerated with each other to form the
secondary particles which have an average secondary particle size
controlled to 10 to 300 nm, and is in the form of colloid
particles, and as a preferable binder, a water-soluble resin. The
resultant ink-receiving layer is a porous layer having a
satisfactory transparency and gloss and an enhanced ink-absorption.
The silica is preferably an amorphous silica.
[0035] In the ink jet recording material of the present invention,
since the specific colloidal particles of silica and/or
aluminosilicate pigment are utilized, the resultant ink-receiving
layer has an enhanced gloss and weathering resistance and capable
of recording ink images with enhanced quality, in comparison with
the conventional ink jet recording materials in which a
conventional alumina or boehmite pigment is employed.
[0036] In the present invention, the pigment particles must be
secondary particles each comprising an agglomeration of a plurality
of primary particles of silica and/or aluminosilicate. Also, the
secondary particles have an average particle size of 10 to 300 nm
and are in the form of colloidal particles. If the conventional
colloidal primary particles of silica and/or aluminosilicate are
directly dispersed in the binder matrix, the resultant
ink-receiving layer has a relatively dense structure and exhibits a
decreased transparency and a reduced ink absorption. Therefore, to
increase the ink-absorption, the ink-receiving layer must be formed
in an increased thickness. The thick ink-receiving layer exhibits a
low resistance to cracking. Also, the thick ink-receiving layer can
be formed by complicated coating procedures. The silica and/or
aluminosilicate secondary particles may contain non-agglomerated
primary particles thereof in a small amount, for example, not
exceeding 40% by weight.
[0037] The colloidal secondary particles of silica and/or
aluminosilicate usable for the present invention have a poor
self-bonding activity. Therefore, in the formation of the
ink-receiving layer, a binder for the colloidal secondary particles
must be used.
[0038] In the ink jet recording material of the present invention,
when a combination of the colloidal secondary particles with a
binder preferably comprising a water-soluble resin, for example, a
polyvinyl alcohol is used as a principal component, an
ink-receiving layer having a satisfactory transparency and a high
gloss similar to that of the photographic paper sheet can be
obtained. Also, since the ink-receiving layer is substantially
transparent, the ink jet recording material of the present
invention can be used for OHP.
[0039] Further, in the production of the ink jet recording sheet of
the present invention, when the ink-receiving layer is formed on a
smooth surface of a shaping base, and transferred and bonded to a
substrate and then the resultant laminate is separated from the
shaping base, the resultant ink-receiving layer has high smoothness
and gloss.
[0040] The ink-receiving layer may be bonded to the substrate
directly or through a bonding or adhesive material layer.
[0041] The conventional colloidal silica pigment is a dispersion of
a plurality of primary particles, and has a lower ink recording
density and ink absorption capacity than those of the specific
secondary particles of silica usable for the present invention.
[0042] The substrate usable for the present invention comprises a
member selected from, for example, regenerated cellulose films
(cellophane); plastic resin films, for example, polyethylene,
polypropylene, soft polyvinyl chloride resin, hard polyvinyl
chloride resin, and polyester films; paper sheets, for example,
wood-free paper sheets, art paper sheets, coated paper sheets,
cast-coated paper sheets, metallic foil-laminated paper sheets,
kraft paper sheets, polyethylene film-laminated paper sheets,
resin-impregnated paper sheets, metal-deposited paper sheets, and
water-soluble paper sheets; metallic foils; and synthetic paper
sheets.
[0043] To obtain an ink-receiving layer having an excellent gloss,
the substrate is preferably formed from a water-impermeable plastic
resin film or resin-laminated paper sheet. When the substrate is
formed from a transparent plastic resin film, the resultant
recording material is a transparent recording material and can be
used for OHP.
[0044] As mentioned above, the pigment particles usable for the
ink-receiving layer of the present invention are secondary
particles formed from primary particles of a member selected from
silica and aluminosilicate having a specific primary particle size
of 3 to 40 nm and are agglomerated with each other. The secondary
particles have a secondary particle size of 10 to 300 nm.
[0045] Generally, a colloidal solution contains a plurality of
colloidal particles having a particle size of about 1,000 nm or
less and uniformly dispersed in a dispersion medium, for example,
an aqueous medium. Accordingly, the silica or aluminosilicate
secondary particles usable for the present invention having a
particle size of 10 to 300 nm are in the form of colloidal
particles. The silica or aluminosilicate secondary particles can be
prepared by any conventional colloid forming method. For example,
the secondary particles can be prepared by applying a strong
mechanical stress to conventional synthetic amorphous silica
agglomerate particles having a particle size of, for example, 1
.mu.m to 50 .mu.m, by using mechanical dividing means. Usually, the
conventional synthetic amorphous silica agglomerate particles
available in trade have a particle size of about 2 to 15 .mu.m.
This preparation method is referred to as a breaking down method
wherein the synthetic amorphous silica particles are finely
divided, while allowing the resultant primary particles to be
agglomerated into secondary particles having an average secondary
particle size of 10 to 300 nm.
[0046] The conventional synthetic amorphous silica agglomerate
particles having a large particle size of 1 .mu.m to 50 .mu.m and
usable for a breaking down procedure can be produced by a wet
method (wet process).
[0047] The typical method of producing silica particles will be
illustrated below.
[0048] The methods of producing the amorphous silica are classified
into wet methods (wet processes) and dry methods (dry processes).
The wet method silica is produced by using, as a starting material,
siliceous sand, mainly silicon dioxide, which exists in large
amounts around the globe. The physical properties of the amorphous
silica can be controlled by the production method. Namely, various
types of amorphous silica having a specific property necessary to
desired use, for example, absorptive separations, catalyst
carriers, and fillers for paints and resins, can be produced. The
wet production methods of the amorphous silica include
gelatinization methods and precipitation methods.
[0049] In the gelation method, the amorphous silica is produced by
mixing sodium silicate produced from a high purity siliceous sand
with sulfuric acid to provide a silicic acid sol, gradually
polymerizing the silicic acid sol so as to form primary particles
and then three-dimensionally to agglomerate the primary particles
with each other into an agglomerate (secondary particles), namely
to gelatinize the sol. By the above-mentioned method, the
agglomerated particles of silica can be prepared while using no
binder. In the method, the amorphous silica particles having
desired BET specific surface area in the range of from 250 to 1500
m.sup.2/g can be produced by controlling the conditions for forming
the primary particles. The resultant amorphous silica is finely
divided to a micrometer size.
[0050] In the precipitation methods, the amorphous silica is
produced under the same conditions as in the gelation method,
except that the growth of the agglomerate (secondary) particles is
stopped by influence of reaction temperature, co-existing ions or
surfactant, and the resultant agglomerate particles are allowed to
precipitate. This type of amorphous silica particles have a small
BET specific surface area. Namely, the precipitated amorphous
silica particle having a BET specific surface area of 25 to 400
m.sup.2/g can be used for the present invention.
[0051] In the dry methods (or dry process), the amorphous silica is
produced by burning and hydrolysing SiCl.sub.4 in gas phase.
Therefore, this method is referred to as dry method against the wet
method. In this dry method, the resultant silica particles have no
pores or inner gaps and no inner surface area and thus exhibit an
ink absorbing property lower than that of the wet method silica
particles.
[0052] The silica particles produced by the dry method have a very
small particle size and form, in water, chained particles in which
individual particles are bonded with each other through hydrogen
bonds. These hydrogen bonds are weak and thus are easily broken
down when shearing forces are applied thereto.
[0053] The differences in the performance of the resultant
amorphous silica pigments between the amorphous silica pigment
production methods are as follows.
[0054] The amorphous silica pigment particles produced by the
gelation method include primary particles having a small particle
size and a strong agglomerating power and thus the resultant
secondary particles have a relatively dense structure.
[0055] In the amorphous silica pigment produced by the
precipitation method, the primary particles have a large particle
size, and a low agglomeration power, and thus the resultant
secondary particles may have a relatively loose structure. The fine
pores are gaps formed between the primary particles agglomerated
with each other and thus the pore volume is a controllable
parameter of the agglomerate particles.
[0056] The amorphous silica primary particles made by the
gelatinization method form agglomerate (secondary) particles having
a higher strength than those produced by the precipitation method.
The strong agglomerate particles are expected to contribute to
enhancing the strength of the coating layer.
[0057] In the ink jet recording material, the agglomerated
amorphous silica particles produced by the wet method are
preferably employed. These agglomerated amorphous silica particles
can be pulverized by, for example, the breaking down method, into
secondary particles having the desired secondary particle size.
[0058] In the wet method silica particles, a plurality of the
primary particles are agglomerated with each other by attraction
force between the primary particles to form a secondary particles
the attraction between the primary particles is due to a force
including hydrogen bonding force between silanol groups located on
the surfaces of the primary particles and van der Waals force
between the primary particles.
[0059] The aluminosilicate particles have an amorphous structure
and can be produced by subjecting a mixture containing, as
principal components, an aluminum alkoxide and a silicon alkoxide
to an hydrolysis procedure, and are a complex product comprising
alumina moieties and silica moieties which are closely combined
with each other to such an extent that these moieties cannot be
isolated from each other. Usually, in the aluminosilicate
particles, the alumina moieties (Al.sub.2O.sub.3) and the silica
moieties (SiO.sub.2) are contained in a weight ratio of 1:4 to 4:1,
preferably about 6:2. The aluminosilicate particles usable for the
present invention may further contain an additional moiety, for
example, titanium alkoxide, zinc alkoxide and calcium alkoxide, in
an amount of 10% by weight or less, preferably 0.1 to 2% by weight.
These additional moiety-containing aluminosilicate particles can be
produced by adding a corresponding metal alkoxide to the additional
moiety to the aluminum alkoxide and silicon alkoxide.
[0060] The aluminosilicate particles are prepared in an alcoholic
atmosphere, and the resultant particles are in the form of
secondary particles having a particle size in the order of
.mu.m.
[0061] To reduce the aluminosilicate secondary particle size to 10
to 300 nm, the above-mentioned aluminosilicate secondary particles
supplied from the preparation process are divided in a medium, for
example, an aqueous medium, by a mechanical dividing means.
[0062] The mechanical dividing means for the silica and
aluminosilicate particles can be selected from, for example,
ultrasonic homogenizers, high speed rotation mills, roller mills,
container-driving medium mills, medium agitating mills, jet mills,
mortar, grinders (in which a material to be ground is placed in a
bowl-shaped container and knead-ground with a pestle-shaped rod),
and sand grinders.
[0063] The average primary and secondary particle sizes of the
silica and aluminosilicate particles can be determined by using an
electron microscope (SEM or TEM). Namely, an electron microscopic
photograph of the particles is taken at a magnification of 10,000
to 400,000, the sizes of the particles located in an area of 5
cm.times.5 cm in the photograph are measured and an average of the
measured particle sizes (martin diameter) is calculated.
[0064] In the present invention, the average size of the secondary
particles of the silica or aluminosilicate is controlled to 10 to
300 nm, preferably 10 to 200 nm, more preferably 10 to 150 nm,
still more preferably 20 to 100 nm.
[0065] If the silica or aluminosilicate secondary particles having
an average particle size of more than 300 nm are used, the
resultant ink-receiving layer exhibits an unsatisfactory
transparency, the resultant ink images exhibit an unsatisfactory
color density and thus an expected ink jet recording material
having a high gloss after printing cannot be obtained. Also, if the
average secondary particle size is smaller than 10 nm, the
resultant ink-receiving layer exhibits an unsatisfactory ink
absorption and ink-adsorbing rate.
[0066] In the present invention, the average size of the primary
particles of silica and aluminosilicate is preferably controlled to
3 to 40 nm, more preferably 3 to 30 nm, still more preferably 5 to
30 nm. If the primary particle size is less than 3 nm, the
resultant particles may have extremely small gaps between the
primary particles and thus exhibit a significantly low capacity for
ink or ink solvent absorption. Also, if the average primary
particle size is more than 40 nm, the resultant secondary
agglomeration particles may have too large a size and the resultant
ink-receiving layer may exhibit an unsatisfactory transparency. In
the ink jet recording material of the present invention, the wet
method silica exhibits a recording property-enhancing effect higher
rather than that of aluminosilicate.
[0067] Since the silica and aluminosilicate particles have a poor
film-forming property, they must be bonded by using a binder to
form the ink-receiving layer. The binder comprises a water-soluble
resin or an aqueous emulsion, a latex, or a dispersion of resin.
The water-soluble resin is preferably selected from polyvinyl
alcohol (PVA), water-soluble modified polyvinyl alcohols, for
example, silanol-modified polyvinyl alcohols, and cation-modified
polyvinyl alcohols, polyvinyl pyrrolidone casein, soybean protein,
synthetic proteins, starch, and water-soluble cellulose
derivatives, for example, carboxy-methylcellulose and
methylcellulose.
[0068] The binder may be an aqueous emulsion, latex or dispersion
of a water-insoluble conjugated diene polymer selected from, for
example, styrene-butadiene copolymers, and methyl
methacrylate-butadiene copolymers. However, a water soluble resin
is preferably used as a binder because the resultant ink receiving
layer exhibits a high ink absorption.
[0069] From the view point of dispersibility and coating liquid
stability, the polyvinyl alcohol is most preferable for the binder.
Especially, the water-soluble resin contributory to enhancing the
ink absorption of the ink-receiving layer is selected from
polyvinyl alcohol having a degree of polymerization of 2,000 or
more, more preferably 2,000 to 5,000. To form an ink-receiving
layer having an enhanced water resistance, the polyvinyl alcohol is
preferably selected from those having a degree of saponification of
95% or more, more preferably, 97% to 100%.
[0070] In the ink-receiving layer of the present invention, there
is no limitation to the solid weight ratio of the binder to the
silica and/or aluminosilicate pigment particles. Preferably, the
binder/pigment ratio is 10:1 to 10:10, more preferably 10:2 to
10:6. If the content of the binder is too high, the resultant
ink-receiving layer has a small total volume of pores and thus
exhibits an unsatisfactory ink absorption. Also, if the content of
the binder is too small, the resultant ink-receiving layer has an
unsatisfactory resistance to cracking and too low a mechanical
strength.
[0071] The ink-receiving layer of the present invention optionally
contains, in addition to the specific silica and/or aluminosilicate
particles and the binder, an additional pigment selected from
conventional inorganic and organic pigments for example, colloidal
silica in the form of primary particles, kaolin, clay, calcined
clay, zinc oxide, tin oxide, magnesium sulfate, aluminum oxide,
aluminum hydroxide, calcium carbonate, satin white, aluminum
silicate, smectites, zeolites, magnesium silicate, magnesium
carbonate, magnesium oxide, diatomaceous earth, thermoplastic resin
pigments, for example, styrene polymer pigments and thermosetting
resin pigments, for example, urea-formaldehyde resin and
benzoguanamine resin pigments. However, to maintain the smoothness
and ink absorption of the ink-receiving layer at a satisfactory
level, the content of the additional pigment is preferably
restricted to a level of not exceeding 20% by weight based on the
weight of the specific silica and/or aluminosilicate particles.
Also, for the purpose of enabling the ink-receiving layer to
exhibit a satisfactory transparency, the particle size of the
additional pigment is preferably 2 .mu.m or less.
[0072] In the ink-receiving layer of the present invention, a
cationic resin is optionally further contained to enhance the
ink-fixing property of the ink-receiving layer. The cationic resin
usable for the purpose is preferably selected from
polyalkylenepolyamine resins, for example, polyethylenepolyamine
and polypropylenepolyamine resins and modified
polyalkylenepolyamine resins, modified polyacrylic resins with a
tertiary amine group or quaternary ammonium group, and diacrylamine
resins. Usually, the cationic resin is contained preferably in an
amount of 1 to 30 parts by weight, more preferably 5 to 20 parts by
weight, per 100 parts of the total weight of the pigment component.
Also, the ink-receiving layer optionally contains an additive
selected from conventional dispersing agents, thickening agent,
antifoaming agents, coloring materials, antistatic agents and
antiseptic agents.
[0073] There is no specific limitation to the amount of the ink
receiving layer.
[0074] The ink-receiving layer of the present invention is provided
preferably in a coating amount of 1 to 100 g/m.sup.2, more
preferably 5 to 60 g/m.sup.2. If the coating amount of the
ink-receiving layer is too small, the increasing layer is difficult
to form with a satisfactory uniformity. Also, if the coating amount
is more than 100 g/m.sup.2, the performance and effect of the
resultant ink-receiving layer are saturated and sometimes the
ink-receiving layer exhibits a reduced resistance to cracking. A
thick ink-receiving layer having a weight of 15 g/m.sup.2 or more
can be obtained by increasing the viscosity of the coating liquid
and/or the total concentration of the solid contents in the coating
liquid for the ink-receiving layer, or by repeatedly coating the
coating liquid two times or more.
[0075] In a preferred embodiment of the ink jet recording material
of the present invention, the image-receiving layer containing the
specific silica and/or aluminosilicate secondary particle have a
plurality of pores formed therein due to the specific secondary
particles and exhibits a pore radius distribution curve in which a
peak appears at a pore radius of 40 nm or less.
[0076] Namely, in this preferable embodiment of the present
invention, an ink-receiving layer formed on a surface of a
substrate comprises a binder matrix comprising a binder, preferably
a water-soluble resin, and a plurality of secondary particles
having an average secondary particle size of 10 to 300 nm,
preferably 10 to 150 nm, dispersed in the binder matrix, and each
comprising a plurality of primary particles of at least one member
selected from silica and aluminosilicate, having an average primary
particle size of 3 to 40 nm and agglomerated with each other to
form the secondary particles, has a plurality of pores formed
therein, and exhibits a pore radius distribution curve having a
peak corresponding to a pore radius of about 40 nm or less.
[0077] The above-mentioned secondary particles preferably have a
total pore volume of 0.1 ml/g or more, more preferably 0.5 ml/g or
more.
[0078] When the ink-receiving layer is formed by coating a surface
of the substrate with a coating liquid containing the specific
silica and aluminosilicate secondary particles, sometimes a small
number of air bubbles are included in the resultant ink-receiving
layer. Also, due to a scattering of the measurement data of the
pore radius in a pore radius tester, the resultant pore radius
distribution curve sometimes has a peak corresponding to a pore
radius of more than 40 nm. However, this peak is smaller than the
peak appearing at a pore radius of 40 nm or less. Also, in the pore
radius distribution curve of the image-receiving layer, a region
corresponding to a pore radius of 6 .mu.m or more may have a small
peak.
[0079] However, in the pore radius distribution curve of the
ink-receiving layer of the present invention, the peak appears in
the region corresponding to a pore radius of 40 nm or less and
substantially no peak appears in the region corresponding to a pore
radius of more than 40 nm but not more than 6 .mu.m. Usually, there
is no lower limit to the pore radius at which a peak appears in the
pore radius distribution curve. The peak may appear at a very small
pore radius of about 1 nm.
[0080] The total volume of the pores having a pore radius of 40 nm
or less corresponds preferably to 40% or more, more preferably 65%
or more, of the total volume of all the pores. In the present
invention, the above-mentioned peak appearing in the pore radius
distribution curve has a height corresponding to about 10% or more
of the height of the highest peak appearing in the pore radius
distribution. Smaller peaks sometimes appear due to the scattering
of the measurement data and thus are usually neglected.
[0081] When the pores included in the ink-receiving layer have the
above-defined pore radius distribution curve, the resultant porous
ink-receiving layer has a high gloss, and satisfactory
transparency, ink-absorbing rate and ink-absorption capacity, and
can receive true circle-shaped ink dots. Also, in the present
invention, the recorded ink images recorded in the ink-receiving
layer has a high color density and brightness, and the resultant
ink-receiving layer has an enhanced weathering resistance and a
high ink-absorbing rate.
[0082] The silica or aluminosilicate particles for the present
invention must be colloidal particles consisting essentially of
secondary particles each composed of a plurality of primary
particles agglomerated with each other. When the ink is absorbed in
the pores formed between the secondary particles and having a
relatively large pore size, the ink is further absorbed in the fine
pores formed between the primary particles in the secondary
particles and having a relatively small pore size, and thus the ink
receiving layer exhibiting enhanced ink absorbing rate, and ink
absorption capacity can be obtained.
[0083] When colloidal particles consisting of primary particles
simply dispersed, for example, colloidal silica particles from the
trade, are used, the resultant ink receiving layer formed by
coating a substrate with a coating composition containing the
colloidal particles has a relatively high density, and the ink can
be absorbed only in the pores formed between the primary particles.
Therefore, to increase the ink absorbing rate and the ink
absorption capacity, primary particles having a large particle size
must be used. The increase in the particle size causes the
transparency of the resultant ink receiving layer to be reduced.
Also, to provide an ink receiving layer having a high ink absorbing
property, the ink receiving layer must be formed in a high coating
amount. The high coating amount causes the resultant ink receiving
layer to exhibit a reduced resistance to cracking and the coating
procedure to be complicated.
[0084] The pigment particles used for the present invention may
contain a small amount of primary particles not agglomerated with
each other.
[0085] In the ink jet recording material of the present invention,
preferably the ink receiving layer includes a plurality of pores
formed therein, the total volume of all the pores is 0.6 ml/g or
more, more preferably 1 ml/g or more, and the total volume of the
pores with a pore size of 3 to 20 nm is 0.3 ml/g or more,
preferably 0.4 ml/g or more. This preferable ink receiving layer
has enhanced transparency, ink-absorbing rate and ink-absorption
capacity and the recorded ink images have enhanced color density
and gloss.
[0086] There is no upper limit to the total volume of all the pores
in the ink-receiving layer. Usually, the total volume of all the
pores can be increased up to about 2.5 ml/g. Also, there is no
upper limit to the total volume of the pores with a pore size of 3
to 20 nm. Usually, the total volume of the pores may be 2.0 ml/g or
more. Preferably the total volume of the pores with a pore size of
3 to 20 nm is 0.4 to 1.5 ml/g.
[0087] Since this type ink-receiving layer is entirely transparent,
when a transparent substrate sheet is used, the resultant ink jet
recording material can be used for OHP. The smoothness and gloss of
the ink-receiving layer can be improved by forming a coating layer
corresponding to the ink-receiving layer on a smooth surface of a
shaping base, bonding a substrate to the coating layer, and then
separating a resultant laminate from the shaping base.
[0088] The pore radius distribution of the ink-receiving layer can
be determined by the following measurement. An ink-receiving layer
is formed on a surface of a thermoplastic film, and then removed
from the thermoplastic film by using a peeling tool, for example, a
cutter knife. If the thermoplastic film has substantially no
influence on the measurement of the pore radius distribution, the
film may not be separated from the ink-receiving layer.
[0089] The measurement specimen is subjected to a cumulative pore
volume measurement by a mercury-forcing method using a micrometrix
poresizer 9320 (trademark, made by Shimazu Seisakusho). A pore
radius distribution is calculated from the cumulative pore volume
test result. The pore size is calculated from the following
equation, on the assumption that the cross-sections of the pores
are circle-shaped.
R=-2.gamma. cos .theta./P
[0090] wherein R represents a radius of pore, .gamma. represent a
surface tension of mercury, .theta. represent a contact angle of
mercury, and P represents a mercury-forcing pressure.
[0091] In the measurement, the surface tension of mercury is
482.536 dye/cm and the contact angle is 130 degrees, the
mercury-forcing pressure is 0 to 30 psia in a low pressure region
for a pore radius to be measured of 180 to 3 .mu.m, and 0 to 30,000
psia in a high pressure region for a pore radius to be measured of
3 .mu.m to 3 nm.
[0092] The cumulative pore volume of the ink-receiving layer
specimen can be calculated from the weight of the specimen and the
cumulative pore volume curve.
[0093] In another preferable embodiment of the ink jet recording
material of the present invention, the ink-receiving layer contains
the specific silica and/or aluminosilicate secondary particles
having an average secondary particle size of 10 to 300 nm,
preferably 10 to 200 nm and has a haze value of 4 to 65% preferably
4 to 55%, more preferably 4 to 35%, still more preferably 4 to 20%.
This type of ink-receiving layer exhibits an enhanced ink-absorbing
rate, ink-absorption capacity, gloss and transparency and the
resultant ink dots recorded thereon are true-circle-shaped.
[0094] The haze value of the ink-receiving layer is measured by the
following method.
[0095] An ink-receiving layer is coated on a transparent
thermoplastic film having a thickness of 75 .mu.m (trademark:
Lumiler T, made by Toray Industries, Inc.), and subjected to a haze
value measurement using a haze meter (reflection and transmission
tester, Model: HR-100, made by Murakami Shikisaigijutsu Kenkyusho).
The measurement is carried out in accordance with JIS K7105 as
follows.
[0096] (1) A standard white plate is fixed to the tester and an
amount of incident light is controlled so that an indicator of the
tester indicates a value Ti of 100.
[0097] (2) A specimen is fixed together with the standard white
plate, and a total amount T.sub.2 of light transmitted through the
specimen is measured.
[0098] (3) The standard white plate and specimen are removed, a
light trap is fixed, and an amount T.sub.3 of light scattered in
the tester is measured.
[0099] (4) The specimen is attached together with the light trap to
the tester, and an amount T.sub.4 of scattered light by the tester
and the specimen is measured.
[0100] (5) Then the haze value of the specimen is calculated in
accordance with the following equations.
Total light transmission Tt(%)=(T.sub.2/T.sub.1).times.100
Defused light transmission
Td(%)={[T.sub.4-T.sub.3(T.sub.2/T.sub.1)]/T.sub- .1}.times.100
Haze value H(%)=(Td/Tt).times.100
[0101] If the haze value is less than 4%, although the resultant
ink-receiving layer may exhibit an enhanced transparency, the
ink-absorbing rate and ink-absorption capacity of the ink-receiving
layer may be unsatisfactory. Also, if the haze value is more than
65%, the resultant ink-receiving layer may exhibit too low a
transparency and the recorded ink images may have an unsatisfactory
color density. The haze value is preferably 4 to 35%, more
preferably 4 to 20%. The haze value of the ink-receiving layer is
variable depending not only on the secondary particle size but also
on the primary particle size of the silica and/or aluminosilicate
colloidal particles. Preferred average secondary particle size is
10 to 200 nm and the preferred average primary particle size is 3
to 40 nm. Also, the haze value of the ink-receiving layer is
variable depending on the amount and refractive index of the
binder. Namely, a gloss ink-receiving layer having a low haze value
(a high transparency) can be obtained by using a binder having a
high transparency.
[0102] Also, even when the ink-receiving layer is formed in an
amount of 10 g/m.sup.2 or more, the color density and gloss of the
printed ink images can be enhanced by adjusting the haze value of
the ink-receiving layer to 4 to 65%, and the resultant ink jet
recording material can record thereon high quantity ink images.
[0103] In still another preferable embodiment of the ink jet
recording material of the present invention, the surface of the
ink-receiving layer has a Bekk smoothness of 1,000 seconds to
record thereon ink images with a high gloss.
[0104] The ink jet recording material of the present invention
optionally further comprises at least one additional ink-absorbent
layer comprising a binder resin and a plurality of pigment
particles. The additional ink-absorbent layer is laminated
preferably between the substrate and the ink-receiving layer.
Namely, in this case, the ink-receiving layer forms an actual
uppermost (or outermost) layer and the additional ink-absorbent
layer forms an actual inside layer of the ink jet recording
material of the present invention.
[0105] The additional ink-absorbent layer may be the same as or
different from the ink-receiving layer in the composition
thereof.
[0106] Where the additional ink-absorbent layer contains, as a
pigment component, the same specific silica and/or aluminosilicate
secondary particles as those of the ink-receiving layer, the
resultant ink jet recording material has most satisfactory gloss
and transparency and can record thereon ink images having most
satisfactory color density, clarity and brightness.
[0107] Nevertheless, a combination of the ink-absorbing layer with
at least one additional ink-absorbent layer containing a pigment
different from the specific silica and/or aluminosilicate secondary
particles can exhibit a satisfactory ink-absorbing rate,
ink-absorption capacity, gloss, transparency, water-resistance and
whethering resistance and can record thereon ink images with
satisfactory color density, clarity and brightness.
[0108] To ensure the high gloss of the ink receiving layer after
printing, the amount of the specific silica and/or aluminosilicate
secondary particle-containing layer is preferably controlled to a
level of 50 to 100% by weight based on the total weight of the
ink-receiving layer and the additional ink-absorbent layer. Even if
the amount of the silica and/or aluminosilicate secondary
particle-containing layer is less than 50%, the resultant ink jet
recording material can exhibit a certain gloss but cannot exhibit a
high gloss and brightness similar to those of photographic paper
sheets.
[0109] When the amount of the specific silica and/or
aluminosilicate secondary particle-containing layer is 50 to 100%
based on the total weight of the ink-receiving layer and the
additional ink-absorbent layer, the resultant gloss and brightness
are similar to those of the conventional photographic paper
sheets.
[0110] As mentioned above, the additional ink-absorbent layer is
preferably located between the substrate and the ink-receiving
layer, and comprises a plurality of pigment particles which are
conventionally used for the coated paper production and have an
average particle size of 0.5 .mu.m or more. The pigment for the
additional ink-absorbent layer is preferably selected from
synthetic amorphous silica, clay, alumina, or smectite particles.
The synthetic amorphous silica pigment is most preferable for
recording ink images having satisfactory color density, clarity and
brightness.
[0111] The additional ink-absorbent layer may comprise the
above-mentioned specific agglomerate particles of silica and/or
aluminosilicate usable for the ink receiving layer.
[0112] In the additional ink-absorbent layer, the binder comprises,
for example, a water-soluble resin, for example, polyvinyl
alcohols, casein and starches as mentioned above, and a latex or
aqueous emulsion or dispersion of a water-insoluble synthetic
resin, for example, a styrene-butadiene copolymer later. Preferably
the water-soluble resin is used.
[0113] The binder is contained preferably in an amount of 5 to 150
parts by weight, more preferably 10 to 50 parts by weight, per 100
parts by total weight of the pigment component. Also, the
additional ink-absorbent layer optionally contains the cationic
resin as mentioned above, to enhance the ink-fixing property
thereof. The cationic resin is contained in an amount of preferably
1 to 30 parts by weight, more preferably 5 to 20 parts by weight,
per 100 parts by total weight of the pigment component. Further,
the additional ink-absorbent layer optionally contains an additive
selected from dispersing agents, thickening agents, antifoaming
agent, coloring materials, antistatic agents and antiseptic agents
which are commonly used for the coated paper production, in a small
amount, for example, 0.01 to 5 parts by weight per 100 parts by
weight of the pigment component.
[0114] There is no limitation to the amount of the additional
ink-absorbent layer. Usually, the amount of the additional
ink-absorbent layer is preferably adjusted to 3 to 30 g/m.sup.2. If
the amount is too small, the resultant additional ink-absorbent
layer has too low an ink-absorption capacity and thus is
meaningless. Also, if the amount is too large, the effect of the
additional ink-absorbent layer is saturated and sometimes results
in an economical disadvantage.
[0115] Even when the ink-receiving layer is formed on the
additional ink-absorbent layer, the ink receiving layer preferably
has a haze value of 4 to 65%, more preferably 4 to 55%, still more
preferably 4 to 35%, further preferably 4 to 20%. Also, the
additional ink-absorbent layer may comprise the specific silica
and/or aluminosilicate secondary particles. To enhance the color
density of the printed ink images, preferably, the average
secondary particle size of the specific silica and/or
aluminosilicate secondary particles in the ink receiving layer is
smaller than the particle size of the pigment component in the
additional ink-absorbent layer.
[0116] The ink-receiving layer and the additional ink-absorbent
layer can be formed on the substrate by using a conventional
coating method and apparatus, for example, a die coater, a blade
coater, air knife coater, roll coater, bar coater, gravure coater,
rod blade coater, lip coater, curtain coater.
[0117] In still another preferable embodiment of the ink jet
recording material of the present invention, the substrate is
transparent. In this embodiment, the ink-receiving layer preferably
comprises the specific silica and/or aluminosilicate secondary
particles having a secondary particle size of 10 to 300 nm,
preferably 10 to 200 nm, and preferably a primary particle size of
3 to 40 nm, and has a haze value of 4 to 65%, more preferably 4 to
55%, still more preferably 4 to 35%, further preferably 4 to
20%.
[0118] The transparent substrate can be formed from transparent
polymeric sheets or films, for example, regenerated cellulose films
(cellophane), and thermoplastic films such as polyethylene,
polypropylene, soft polyvinyl chloride resin, hard polyvinyl
chloride resin, polyester (polyethylene terephthalate, etc.) films.
The transparent substrate preferably has a haze value of 20% or
less.
[0119] Further preferably, the ink-receiving layer contains the
specific silica and/or aluminosilicate colloidal particles having
an average primary particle size of 3 to 30 nm and an average
secondary particle size of 10 to 100 nm more preferably 20 to 80
nm, and has, as a whole, a haze value of 20% or less. The haze
value of the ink jet recording material can be determined in
accordance with the measurement method mentioned above.
[0120] The above-mentioned type of ink jet recording material of
the present invention exhibits high transparency, ink-absorbing
property, water resistance, whethering resistance, can record
thereon ink images with high color density and clarity, and thus is
useful as a transparent ink jet recording sheet for, for example,
OHP. If the haze value is more than 20%, the resultant ink jet
recording sheet is not suitable for OHP, because in this case, the
projected images from the ink jet recording sheet onto OHP may be
unclear.
[0121] There is no lower limit to the haze value. The haze value
may be small, for example, 5% or less.
[0122] When an ink jet recording material having a haze value of
20% or less is designed, the primary and secondary particle sizes
of the silica and/or aluminosilicate particles should be controlled
to the specific values as defined in the present invention. If the
average primary and/or secondary particle size is too small, the
resultant ink-receiving layer may exhibit an unsatisfactory
ink-absorption property. In this case, to enhance the
ink-absorption property, the thickness of the ink-receiving layer
must be undesirably increased. The thick ink-receiving layer
exhibits a reduced resistance to cracking.
[0123] In the ink jet recording material of the present invention,
the ink-receiving layer and optionally the additional ink-absorbent
layer can be directly formed on a surface of the substrate by using
a coating apparatus. Alternatively, in another process for
producing the ink jet recording material of the present invention,
the ink receiving layer is formed on a surface, especially a
smoothed surface, of a shaping base; a substrate is bounded to the
ink-receiving layer on the shaping base; and then the resultant
laminate is separated from the shaping base surface. The resultant
ink-receiving layer surface has an enhanced smoothness and gloss.
The ink receiving layer on the shaping base may be bonded to the
substrate through an intermediate layer comprising a bonding
material or an adhesive material. The intermediate layer may be
formed on a surface of the substrate and then the substrate surface
may be bonded to the ink-receiving layer on the shaping base
surface through the intermediate layer. Otherwise, the intermediate
layer may be formed on the ink-receiving layer on the shaping base
and then the substrate is bonded to the intermediate layer.
[0124] The above-mentioned method using the smooth shaping base is
especially advantageous in that the resultant ink-receiving layer
containing the specific silica and/or aluminosilicate secondary
particles can exhibit enhanced smoothness and gloss.
[0125] The bonding of the ink-receiving layer formed on the shaping
base surface to the substrate is preferably carried out by a
conventional laminating method, for example, dry laminating method,
wet laminating method, hot melt laminating method or extrusion
laminating method.
[0126] In the wet, dry and hot melt laminating methods, preferably,
an intermediate layer comprising a bonding or adhesive material is
formed on a surface of the substrate, and then the intermediate
layer on the substrate is superposed on the ink-receiving layer
formed on the shaping base, they are bonded under pressure, and
then the resultant laminate is separated from the shaping base to
obtain an ink jet recording material.
[0127] In the extrusion laminating method, a melt of a
thermoplastic resin, for example, a polyethylene resin melted at a
temperature of 280 to 320.degree. C., is prepared in a
melt-extruder and then extruded through a film-forming slit onto a
surface of a substrate to form an intermediate layer; the ink
receiving layer formed on the shaping base is superposed on the
intermediate layer on the substrate; they are bonded to each other
under pressure while cooling by a cooling roll, and then the
resultant laminate is removed from the shaping base.
[0128] When a pressure-sensitive adhesive is used for the
intermediate layer, a surface of the substrate is coated with the
pressure-sensitive adhesive by a conventional coating method, for
example, bar coater, roll coater or lip coater; the coated adhesive
layer is dried; the dried adhesive layer is laminated on the
ink-receiving layer formed on the shaping base; and then the
resultant laminate is removed from the shaping base to obtain a ink
jet recording material.
[0129] There is no specific limitation to the amount of the
intermediate layer as long as the resultant intermediate layer can
firmly bond the ink-receiving layer to the substrate therethrough.
Usually, the intermediate layer formed from a thermoplastic resin,
bonding material or pressure-sensitive adhesive is preferably in an
amount of 2 to 50 g/m.sup.2. If the amount of the intermediate
layer is too small, the bonding strength of the substrate to the
ink-receiving layer may be unsatisfactory. Also, the intermediate
layer is formed in too large an amount, the bonding strength may be
saturated and an economical disadvantage may occur.
[0130] The intermediate layer for bonding the ink-receiving layer
to the substrate can be formed from a member selected from
thermoplastic polymers, for example, ethyl cellulose, vinyl acetate
polymer, copolymers and derivatives thereof, polyethylene,
ethylene-vinyl acetate copolymers, polyvinyl alcohols, acrylic
resins, polystyrene, styrene copolymers, polyisobutylene,
hydrocarbon resins, polypropylene, polyamide resins, and polyester
resins; bonding materials, for example, thermosetting resins such
as urea resins, phenol resins, epoxy resins, and polyisocyanate
resins, composite polymer-type bonding agents such as polyvinyl
acetal/phenol resin, rubber/phenol resin, and epoxy resin/nylon
resin, rubber-based bonding materials, for example, rubber
latex-type bonding agents, and hydrophilic natural polymer bonding
agents such as starch, glue and casein; and pressure-sensitive
adhesives, for example, solvent type pressure-sensitive adhesives,
emulsion type pressure-sensitive adhesives, hot melt-type
pressure-sensitive adhesives and delayed type pressure-sensitive
adhesives.
[0131] The shaping base is formed from a member selected from
polymer films, for example, regenerated cellulose, polyethylene,
polypropylene, soft polyvinyl chloride resin, hard polyvinyl
chloride resin, and polyester films; surface-smoothed paper sheets,
for example, glassine-paper sheets, coated paper sheets, for
example, polyethylene-laminated paper sheets, resin-impregnated
paper sheets and metallized paper sheets; metal foils, for example,
aluminum foil, and synthetic paper sheets; and plates of inorganic
glasses, metals and plastics, which have a high smooth surface.
Especially, polymer films, for example, polyethylene, polypropylene
and polyester films, polyethylene-laminated paper sheets, glassine
paper sheets and inorganic glass plates and metal plates are
advantageously used for the shaping base, because they can be
easily coated with a coating liquid for the ink-receiving layer and
allow the resultant laminate to be easily separated from the
shaping base.
[0132] To obtain a high gloss ink-receiving layer, the shaping base
has a shaping surface with a high smoothness. The shaping surface
preferably has a surface roughness Ra of 0.5 .mu.m or less, more
preferably, 0.05 .mu.m or less, determined in accordance with
Japanese Industrial Standard (JIS) B 0601.
[0133] The shaping base surface can be used without applying any
surface treatment thereto. To enhance the release property of the
resultant ink-receiving layer from the shaping base, the shaping
surface is preferably coated with a releasing agent, for example, a
silicone resin or fluorine-containing resin. Also, to enhance the
affinity of the shaping base surface to the coating liquid for the
ink-receiving layer, the shaping base surface may be hydrophillized
by applying a corona-discharge treatment or a plasma treatment
thereto.
[0134] Where an additional ink-absorbent layer is contained in the
ink jet recording material, firstly the shaping base surface is
coated with the ink-receiving layer and then with the additional
ink-absorbent layer. Then the substrate is bonded to the additional
ink absorbent layer formed on the ink-receiving layer, through an
intermediate layer or without using the intermediate layer. In this
case, at least the ink receiving layer, contains fine pigment
particles having an average particle size of 50 nm or less,
preferably pigment secondary particles having an average secondary
particle size of 10 to 300 nm, still more preferably the
above-mentioned silica or aluminosilicate secondary particles.
[0135] In an embodiment of the process of the present invention for
producing the ink jet recording material, the ink-receiving layer
formed on the shaping base is directly bonded to the substrate
which may be coated with an additional ink-absorbent layer, without
using the intermediate layer.
[0136] Generally, it has been realized that the dry ink-receiving
layer cannot be directly bonded to the substrate when no adhesive
intermediate layer is used. The inventors of the present invention
attempted to firmly bond the dry ink-receiving layer to the
substrate without using a bonding material and found that the dry
ink-receiving layer formed on the shaping base surface can be
firmly bonded to the substrate with a bonding strength (mainly
derived from Van Der Waals attraction therebetween) higher than the
adhesive strength between the dry ink-receiving layer and the
shaping base surface, by controlling the bonding temperature and
the bonding pressure between the dry ink-receiving layer and the
substrate superposed on the ink-receiving layer. In this case, the
resultant laminate can be separated from the shaping base surface
without separation between them, and the resultant ink jet
recording material has high smoothness and high gloss and can
record thereon ink images with a high color density and
clarity.
[0137] The same firm bonding as mentioned above can be attained
even when the substrate is bonded to an additional ink-absorbent
layer formed on the shaping base. Similarly, the additional
ink-absorbent layer bonded to the substrate can be firmly bonded to
the ink-receiving layer formed on the shaping base. Also, two or
more additional ink-absorbent layers successively formed on the
shaping base can be successively bonded on the substrate in the
above-mentioned way and finally, firmly bonded to the ink-receiving
layer formed on the shaping base. In this case, each additional
ink-receiving layer separated from the shaping base has a smooth
surface and thus can be firmly bonded to an adjacent additional
ink-absorbent layer or to the ink-receiving layer by the
press-bonding procedure without using the bonding material, and
resultant composite coating layer consisting of the additional
ink-absorbent layer(s) and the ink-receiving layer exhibits an
enhanced resistance to cracking.
[0138] In the process of the present invention for producing the
ink jet recording material, the press bonding of the ink-receiving
layer to the substrate or the additional ink-absorbent layer bonded
to the substrate is preferably carried out after wetting at least
one of the ink-receiving layer and the substrate or the additional
ink-absorbent layer on the substrate with a small amount of water
or water vapor. The water or water vapor is contributory to
enhancing the bonding strength and/or the bonding rate of the
ink-receiving layer to the substrate or the additional
ink-absorbent layer on the substrate.
[0139] In the process of the present invention for producing the
ink jet recording material, the content of water or solvent in the
ink-receiving layer or the additional ink-absorbent layer formed on
the shaping base is preferably controlled to a level of 50% by
weight or less, more preferably 20% by weight or less, still more
preferably 10% by weight or less, based on the total dry weight of
the layer. Compared with this process, if a conventional wet
laminating method is applied, the substrate paper sheet may have a
wavy or corrugated surface. Also, in the conventional wet
laminating method, a wet resin layer laminated on the substrate
must be dried, and thus the substrate must have a porous structure
which will allow a vapor of water or solvent to permeate
therethrough. The above-mentioned process of the present invention
is substantially free from the above-mentioned disadvantageous of
the wet lamination method.
[0140] In the process of the present invention for producing the
ink jet recording material, the ink-receiving layer formed on the
shaping base is directly press-bonded to the substrate or to the
additional ink-absorbent layer. There is no specific limitation to
the bonding pressure. Usually, the press-bonding is carried out
preferably under a linear pressure of 1 to 250 kg/cm, more
preferably 3 to 120 kg/cm. If the bonding pressure is too low, the
resultant bonding strength between the ink-receiving layer and the
substrate or the additional ink-absorbent layer may be
unsatisfactory. Also, if the bonding pressure is too high, the
ink-receiving layer and/or the substrate or the laminate of the
additional ink-absorbent layer and the substrate may be crushed and
the ink-absorption capacity of the ink receiving layer and/or the
additional ink-absorbent layer may be significantly decreased.
[0141] The press-bonding apparatus is not limited to a specific
apparatus. Usually, a super calendar is preferably utilized for the
press-bonding. Also, the super calendar preferably has a pair of
metal rollers which have a high resistance to damage, deformation,
and wear and a high durability in practical use.
[0142] In the press-bonding procedure, the bonding temperature is
not limited to a specific temperature. Usually, the press-bonding
is carried out preferably at a temperature of 35 to 150.degree. C.,
more preferably 50 to 100.degree. C. The bonding heat is supplied
from, for example, bonding rolls, to the objects to be bonded. If
the bonding temperature is too low, the resultant bonding strength
between the ink-receiving layer and the substrate or the additional
ink-absorbent layer may be unsatisfactory. Also, if the bonding
temperature is too high, the ink-receiving layer, the substrate
and/or the additional ink-absorbent layer may be crushed or
deformed. Practically, the press-bonding procedure is carried out
under the above-mentioned pressure while heating.
[0143] When water or water vapor is supplied to the ink-receiving
layer, the substrate or the additional ink-absorbent layer to be
subjected to the press-bonding procedure, the amount of water to be
contained in the above-mentioned layer or substrate is not limited
to a specific amount. Usually, the amount of water is controlled
preferably to 0.1 to 10 g/m.sup.2, more preferably 2 to 8
g/m.sup.2. If the water amount is too small, the bonding effect may
not be satisfactorily promoted. If the water amount is too much,
the bonding effect may be saturated.
[0144] When water or water vapor is absorbed by at least one of the
above-mentioned layers and substrate, the close contact between the
layers or substrate is promoted and thus the bonding strength is
enhanced and the transfer of the ink-receiving layer from the
shaping base to the substrate side can be easily effected. By
applying water or water vapor, the necessary bonding temperature
and/or pressure can be reduced. For applying water, a conventional
coating device, for example, blade coater, air knife coater, roll
coater, bar coater, gravuor coater, rod blade coater, lip coater or
curtain coater can be utilized.
[0145] When water vapor is used, the ink-receiving layer and the
additional ink-absorbent layer which have a plurality of pores for
absorbing the ink, and a porous substrate, for example, paper
sheet, can rapidly absorb the water vapor in the pores and wetted
with water. The water vapor method can accurately and uniformly
control the amount of water absorbed by the above-mentioned layers
or substrate, so as to prevent the uneven shrinkage or elongation
of the layers or substrate.
[0146] When water vapor is used, the amount of water absorbed by
the ink-receiving layer, the substrate or the additional
ink-absorbent layer is preferably controlled to 5 to 300%, more
preferably 10 to 150%, still more preferably 20 to 100%, based on
the absolute dry weight of the above-mentioned ink-receiving layer,
substrate or additional ink-absorbent layer. If the water vapor is
absorbed in too small an amount, the bonding-promotion effect of
water vapor may be insufficient, and the ink-receiving layer may
not be smoothly transferred. Also, if the absorbed amount of water
vapor is too large, the ink-receiving layer or the additional
ink-absorbent layer may be deformed (shrunk or elongated) during
the press-bonding procedure, and the deformation may causes the
resultant ink jet recording material to be curled after drying.
[0147] The water vapor can be supplied by utilizing a water
vapor-spouting device (which is attached to a coating apparatus and
used for controlling curling of the resultant ink jet recording
material), an ultrasonic water vapor-generating device or other
water vapor-generating device.
[0148] The ink applicable for the ink jet recording material of the
present invention can be selected from conventional inks for the
ink jet recording system.
[0149] The ink comprises, as indispensable components, a coloring
material for forming visual images and a liquid medium for
dissolving or dispersing the coloring material therein and, as
optional components, a dispersing agent, surfactant,
viscosity-regulating agent, specific resistance regulating agent,
pH-regulating agent, mildewproofing agent, and solution or
dispersion-stabilizer for the coloring material.
[0150] The coloring material for the ink for the present invention
is not limited to specific materials. Usually, the coloring
material is selected from direct dyes, acid dyes, basic dyes,
reactive dyes, coloring matters for foods, disperse dyes, oil dyes
and coloring pigments. The content of the coloring material is
variable depending on the type of the coloring material, the type
of the liquid medium and properties required to the ink. Usually,
the coloring material is contained in a concentration of 0.1 to 20%
by weight in the ink usable for the ink jet recording material of
the present invention.
[0151] The liquid medium for the ink is usually selected from water
and water-soluble organic solvents, for example, alkyl alcohols
having 1 to 4 carbon atoms such as methyl alcohol, ethyl alcohol,
n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, and isobutyl
alcohol; ketones and ketone alcohols, for example, acetone and
diacetone alcohol; polyalkylene glycols, for example, polyethylene
glycol and polypropylene glycols; alkylene glycols of which the
alkylene group has 2 to 6 carbon atoms, for example, ethylene
glycol, propylene glycol, butylene glycol, triethylene glycol,
thiodiglycol, hexylene glycol and diethylene glycol; amide
compounds, for example, dimethylformamide; ether compounds, for
example, tetrahydrofuran, and lower alkyl ethers of polyhydric
alcohols, for example, ethyleneglycol methyl-ether,
diethyleneglycol methyl (or ethyl) ether, triethyleneglycol
monomethyl ether.
EXAMPLES
[0152] The present invention will be further illustrated by the
following examples.
Example Group I
Examples I-1 to I-13 and Comparative Examples I-1 to I-9
[0153] In Example Group I, the following pigments were used.
[0154] (1) Silica colloidal particles A-1
[0155] An aqueous colloidal solution of silica colloidal particles
A-1 having a concentration of 8% by weight was prepared by
dispersing wet method synthetic amorphous silica particles having
an average primary particle size of 16 nm and an average secondary
particle size of 9 .mu.m and available under a trademark of Nipsil
LP from Nihon Silica Kogyo K.K. in water and pulverizing the
particles by repeating a combination of a sand grinder treatment
and an ultrasonic homogenizer treatment until the average secondary
size of the pulverized silica particles reached 50 nm.
[0156] (2) Silica colloidal particles B-1
[0157] An aqueous colloidal solution of silica colloidal particles
B-1 having a concentration of 12% by weight was prepared by
dispersing wet method synthetic amorphous silica particles having
an average primary particle size of 21 nm and an average secondary
particle size of 9 .mu.m and available under a trademark of Nipsil
NS from Nihon Silica Kogyo K.K. in water and pulverizing by
repeating a combination of a sand grinder treatment and an
ultrasonic homogenizer treatment until the average secondary size
of the pulverized silica particles reached 100 nm.
[0158] (3) Silica colloidal particles C-1
[0159] An aqueous colloidal solution of silica colloidal particles
C-1 having a concentration of 15% by weight was prepared by
dispersing wet method synthetic amorphous silica particles having
an average primary particle size of 11 nm and an average secondary
particle size of 3 .mu.m and available under a trademark of Nipsil
HD-2 from Nihon Silica Kogyo K.K. in water and pulverizing by
repeating a combination of a sand grinder treatment and an
ultrasonic homogenizer treatment until the average secondary size
of the pulverized silica particles reached 200 nm.
[0160] (4) Silica colloidal particles D-1
[0161] An aqueous colloidal solution of comparative silica
colloidal particles D-1 having a concentration of 15% by weight was
prepared by dispersing wet method synthetic amorphous silica
particles having an average primary particle size of 16 nm and an
average secondary particle size of 9 .mu.m and available under a
trademark of Nipsil LP from Nihon Silica Kogyo K.K. in water and
pulverizing by repeating a combination of a sand grinder treatment
and an ultrasonic homogenizer treatment until the average secondary
size of the pulverized silica particles reached 500 nm.
[0162] (5) Aluminosilicate particles A
[0163] Isopropyl alcohol in an amount of 100 g was charged in a
glass reactor having a capacity of 2 liters and equipped with a
separable flask, 3 agitating blades each having a diameter of 3 cm
and a thermometer and heated to a temperature of 60.degree. C. by
using an oil bath heater. Then, 5g of aluminum isopropoxide was
added to isopropyl alcohol while agitating the resultant reaction
mixture with the 3 agitating blades at a rotation of 100 rpm.
Thereafter, 1.0 g of an acid catalyst consisting of acetic acid was
added to the reaction mixture and the agitation was continued,
while refluxing at the above-mentioned temperature, for 24
hours.
[0164] Separately, 100 g of ion-exchanged water was charged in the
same type of the glass reactor as mentioned above, and heated to a
temperature of 60.degree. C., 1.8 g of ethyl orthosilicate were
added to the water, 1 g of an acid catalyst consisting of nitric
acid was added to the resultant solution, and then the reactant
reaction mixture was agitated at the above-mentioned temperature
for 24 hours, while refluxing.
[0165] The ethyl orthosilicate-nitric acid-ion-exchanged
water-reaction product solution was mixed into the aluminum
isopropoxide-acetic acid-isopropyl alcohol-reaction product
solution, the resultant reaction mixture was agitated at a
temperature of 60.degree. C. for 6 hours, to produce
aluminosilicate fine particles. The resultant dispersion was
concentrated at a temperature of 60.degree. C. in an evaporator, to
obtain agglomerated secondary particles of aluminosilicate. In the
aluminosilicate secondary particles, the molar ratio of alumina to
silica was 3:2. The primary particles of the aluminosilicate had an
average primary particle size of 10 nm.
[0166] The aluminosilicate secondary particles were diluted with
water and pulverized by repeating a combination of a sand grinder
treatment with an ultrasonic homogenizer treatment until the
average secondary particle size of the aluminosilicate particles
reached 60 nm. The resultant aqueous colloidal solution of the
aluminosilicate secondary particles had a concentration of 8% by
weight.
Example I-1
[0167] An aqueous silica colloidal coating solution having a solid
content of 8% by solid weight was prepared from the silica
colloidal solution A-1 in an amount of 100 parts by solid weight,
and 40 parts by weight of polyvinyl alcohol (available under the
trademark of PVA-124, from Kuraray Co., Ltd.) having a degree of
polymerization of 2400 and a degree of saponification of 98.5%.
[0168] A substrate sheet was prepared by laminating a surface of a
coated paper sheet (available under the trademark of OK Coat from
OJI PAPER CO. Ltd.) having a basis weight of 127.9 g/m.sup.2 with a
polyethylene resin layer having a thickness of 15 pn by an
extrusion-laminating method. This polyethylene resin-laminated
paper sheet will be referred to as a laminated paper sheet
hereinafter.
[0169] The aqueous silica colloidal coating solution was coated on
a surface of the laminated paper sheet by using a Mayer bar and
dried to form an ink-receiving layer with a dry weight of 20
g/m.sup.2.
[0170] An ink jet recording sheet was obtained.
Example I-2
[0171] An ink jet recording sheet was prepared by the same
procedures as in Example I-1 except that in place of the polyvinyl
alcohol (PVA-124), another polyvinyl alcohol (available under the
trademark of PVA-117, from Kuraray Co., Ltd.) having a degree of
polymerization of 1800 and a degree of saponification of 98.5% was
used.
Example I-3
[0172] An ink jet recording sheet was prepared by the same
procedures as in Example I-1 except that in place of the polyvinyl
alcohol (PVA-124), another polyvinyl alcohol (available under the
trademark of PVA-224, from Kuraray Co., Ltd.) having a degree of
polymerization of 2400 and a degree of saponification of 88.5% was
used.
Example I-4
[0173] An ink jet recording sheet was prepared by the same
procedures as in Example I-1 except that in place of the polyvinyl
alcohol (PVA-124), another polyvinyl alcohol (available under the
trademark of PVA-135H, from Kuraray Co., Ltd.) having a degree of
polymerization of 3500 and a degree of saponification of 99% or
more was used.
Example I-5
[0174] An ink jet recording sheet was prepared by the same
procedures as in Example I-1 except that in place of the polyvinyl
alcohol (PVA-124), another polyvinyl alcohol (available under the
trademark of PVA-140H, from Kuraray Co., Ltd.) having a degree of
polymerization of 4000 and a degree of saponification of 99% or
more was used.
Example I-6
[0175] An ink jet recording sheet was prepared by the same
procedures as in Example I-1 except that an aqueous silica
colloidal coating solution having a solid content of 12% by weight
was prepared from the silica colloidal solution B-1 in an amount of
100 parts by solid weight and 40 parts by weight of the polyvinyl
alcohol (PVA-124), and coated on the laminated paper sheet to form
an ink-receiving layer in a dry amount of 20 g/m.sup.2.
Example I-7
[0176] An ink jet recording sheet was prepared by the same
procedures as in Example I-1 except that an aqueous silica
colloidal coating solution having a solid content of 15% by weight
was prepared from the silica colloidal solution C-1 in an amount of
100 parts by solid weight and 40 parts by weight of the polyvinyl
alcohol (PVA-124), and coated on the laminated paper sheet to form
an ink-receiving layer in a dry weight of 20 g/m.sup.2.
Example I-8
[0177] An ink jet recording sheet was prepared by the same
procedures as in Example I-1 except that the aqueous silica
colloidal coating solution was coated on a surface of a shaping
base consisting of a polyethylene terephthalate film (available
under the trademark of Lumilar T from Toray) having a thickness of
75 .mu.m and a surface roughness Ra of 0.02 .mu.m, and dried, to
form a coating layer having a dry weight of 20 g/m.sup.2.
[0178] Then, an polyacrylic acid adhesive (available under the
trademark of A-02, from Nihon Carbide Kogyo K.K.) was coated on a
surface of the dried colloidal silica layer and dried to form an
intermediate layer having a dry weight of 10 g/m.sup.2.
[0179] The intermediate layer on the dried colloidal silica layer
was superposed on and press-bonded to the laminated paper sheet
under a linear pressure of 50 kg/cm by using a calender. Then the
resultant laminate was separated from the shaping base film, to
provide an ink jet recording sheet.
Example I-9
[0180] An aqueous aluminosilicate colloidal solution having a solid
content of 8% by weight was prepared from the aluminosilicate
colloidal solution A in an amount of 100 parts by solid weight and
40 parts by weight of polyvinyl alcohol (available under the
trademark of PVA-135H, from Kuraray Co., Ltd.) having a degree of
polymerization of 3500 and a degree of saponification of 99% or
more.
[0181] The aqueous aluminosilicate colloidal coating solution was
coated on a surface of the laminated paper sheet by using a Mayer
bar and dried to form an ink-receiving layer with a dry weight of
20 g/m.sup.2.
[0182] An ink jet recording sheet was obtained.
Comparative Example I-1
[0183] An ink jet recording sheet was prepared by the same
procedures as in Example I-1 except that an aqueous silica
colloidal coating solution having a solid content of 15% by weight
was prepared from the silica colloidal solution D-1 in an amount of
100 parts by solid weight and 40 parts by weight of the polyvinyl
alcohol (PVA-124), and coated on the laminated paper sheet to form
an ink receiving layer in a dry weight of 20 g/m.sup.2.
Comparative Example I-2
[0184] An ink jet recording sheet was prepared by the same
procedures as in Example I-1 except that an aqueous silica
dispersion having a solid content of 15% by weight was prepared
from 100 parts by solid weight of wet method synthetic amorphous
silica particles (available under a trademark of Nipsil HD-2, from
Nihon Silica Kogyo K.K.) having an average primary particle size of
11 nm and an average secondary particle size of 3 .mu.m and 40
parts by weight of polyvinyl alcohol (PVA-124), and coated on a
surface of the laminated paper sheet by using a Mayer bar and dried
to form an ink-receiving layer having a dry weight of 20
g/m.sup.2.
Comparative Example I-3
[0185] An ink jet recording sheet was prepared by the same
procedures as in Example I-1 except that an aqueous silica
dispersion having a solid content of 15% by weight was prepared
from 100 parts by solid weight of wet method synthetic amorphous
silica particles (available under a trademark of Nipsil LP, from
Nihon Silica Kogyo K.K.) having an average primary particle size of
16 nm and an average secondary particle size of 9 .mu.m, and 40
parts by weight of polyvinyl alcohol (PVA-124), and coated on a
surface of the laminated paper sheet by using a Mayer bar and dried
to form an ink-receiving layer having a dry weight of 20
g/m.sup.2.
Comparative Example I-4
[0186] An ink jet recording sheet was prepared by the same
procedures as in Example I-1 except that an aqueous alumina
dispersion having a solid content of 8% by weight was prepared from
100 parts by solid weight of primary alumina particles (available
under a trademark of Alumina sol-100, from Nissan Kagakukogyo K.K.)
having average minor and major axes of primary particles of 10 nm
and 100 nm, respectively, and 40 parts by weight of polyvinyl
alcohol (PVA-124), and coated on a surface of the laminated paper
sheet by using a Mayer bar and dried to form an ink-receiving layer
having a dry weight of 20 g/m.sup.2.
Comparative Example I-5
[0187] An ink jet recording sheet was prepared by the same
procedures as in Example I-1 except that an aqueous silica
dispersion having a solid content of 15% by weight was prepared
from 100 parts by solid weight of an anionic primary silica
particle colloidal solution (available under a trademark of Snowtex
YL, from Nissan Kagakukogyo K.K.) having an average primary
particle size of 65 nm, and 10 parts by weight of polyvinyl alcohol
(PVA-124), and coated on a surface of the laminated paper sheet by
using a Mayer bar and dried to form an ink-receiving layer having a
dry weight of 20 g/m.sup.2.
Comparative Example I-6
[0188] An aqueous coating liquid having a solid content of 15% by
weight was prepared from 100 parts by solid weight of thesilica
colloidal solution A-1 and 100 parts by solid weight of a
styrene-butadiene copolymer latex (trademark: Nipol LX 415A, made
from Nihon Zeon Co., Ltd.) having an average particle size of 110
nm and a Tg of 27.degree. C.
[0189] The aqueous coating layer was coated on a surface of the
laminated paper sheet by using a Mayer bar and dried to form an
ink-receiving layer having a dry weight of 20 g/m.sup.2. An ink jet
recording sheet was obtained.
Comparative Example I-7
[0190] An aqueous solution of 10% by weight of a polyvinyl alcohol
having a degree of polymerization of 1800 and a degree of
saponification of 98.5% (available under a trademark of PVA-117,
from Kuraray Co., Ltd.) was coated on a surface of the laminated
paper sheet by using a Mayer bar to form an ink-receiving layer
having a dry weight of 20 g/m.sup.2. An ink jet recording sheet was
obtained.
Comparative Example I-8
[0191] A gloss ink jet recording sheet having an ink-fixing layer
and a gloss layer (available under the trademark of GP-101, from
Canon Corp.) was subjected to the tests explained below.
Comparative Example I-9
[0192] An ink jet recording sheet was prepared by the following
procedures.
[0193] (1) Composition of a coating solution for forming an
ink-receiving layer
1 (i) Dry method silica fine 10 parts by weight particles (average
primary particle size: 7 nm, refractive index: 1.45, number of
silanol groups on surface: 2-3/nm.sup.2, trademark: Aerosil A300
(available from Nippon Aerosil Co., Ltd.)) (ii) Polyvinyl alcohol
3.3 parts by weight (saponification degree: 88%, polymerization
degree: 3,500, trademark: PVA23 (available from Kuraray Co., Ltd.))
(iii) Ion exchanged water 136.0 parts by weight
[0194] The dry method silica fine particles (i) are introduced into
a part of the ion exchanged water (iii) (73.3 parts by weight) and
dispersed therein at 10,000 rpm for 20 minutes using a high-speed
rotary wet colloid mill (Creamix, produced by M Technique Co.
Ltd.). To the resulting dispersion was added an aqueous polyvinyl
alcohol solution (solution obtained by dissolving polyvinyl alcohol
in the remainder (62.7 parts by weight) of the ion exchanged water
(iii)), and dispersing was carried out. Then, pH was adjusted to 4
to 5, to obtain a coating solution for forming an ink-receiving
layer.
[0195] (2) Coating and drying
[0196] The coating solution was coated on a surface of the same
laminated paper sheet as in Example I-1 by using a Mayer bar and
dried to form an ink-receiving layer having a dry weight of 20
g/m.sup.2. An ink jet recording sheet was obtained.
[0197] The ink jet recording sheets of Examples I-1 to I-9 and
Comparative Examples I-1 to I-9 were subjected to the following
water-resistance, ink-absorption and ink absorption capacity
tests.
[0198] The specimens of the ink recording sheets of Examples I-1 to
I-9 and Comparative Examples I-1 to I-7 were calender-treated under
a linear pressure of 20 kg/cm before the tests.
[0199] The gloss and ink-absorbing properties were represented by a
gloss, an ink-absorption and color density of ink images of a solid
printed portion of the specimen printed by a practical ink jet
printer (trademark: BJC-600J, made by Canon Inc.).
[0200] [Water Resistance]
[0201] A water drop was placed on the ink-receiving layer surface
of the specimen, 30 minutes after the water drop-placing, the water
drop was wiped out, the water drop-placed portion of the specimen
was rubbed with a finger, and the rubbing result was evaluated in
the following four classes.
[0202] 4 . . . No change appears in the ink-receiving layer
portion.
[0203] 3 . . . The ink-receiving layer portion was slightly
removed.
[0204] 2 . . . The ink-receiving layer portion was certainly
removed.
[0205] 1 . . . The ink-receiving layer portion was completely
removed.
[0206] [Ink Absorption]
[0207] (a) Ink absorbing rate
[0208] Each of yellow, magenta and cyan-colored inks was printed on
the specimen, every 5 seconds after the printing, a woodfree paper
sheet was put on the ink-printed portion of the specimen, and it
was observed whether or not the ink was transferred to the paper
sheet. The time necessary to completely fix the ink in the ink
receiving layer so that no ink transfer occurred on the specimen
was determined. The ink absorption rate was evaluated in four
classes as follows.
[0209] 4 . . . Less than 5 seconds
[0210] 3 . . . 5 seconds or more but less than 10 seconds
[0211] 2 . . . 10 seconds or more but less than 30 seconds
[0212] 1 . . . 30 seconds or more
[0213] The specimen having an ink-fixing time of less than 10
seconds is evaluated as to be excellent in ink-absorbing rate.
[0214] (b) Ink absorption capacity
[0215] On a portion having an area of 10 cm.times.10 cm of a A4
size specimen, yellow, magenta and cyan-colored inks were
successively solid-printed. To observe whether or not the inks
flowed out from the solid printed portion of the specimen, a
woodfree paper sheet was put on the solid printed portion of the
specimen at each stage of immediately one minute, 2 minutes and 5
minutes after the printing, and it was observed whether or not the
inks were transferred to the paper sheet, to determine the time
necessary to completely fix the inks in the ink-receiving layer so
that no ink transfer occurred to the paper sheet. The results were
evaluated in the following four classes.
[0216] 4 . . . Less than one minute
[0217] 3 . . . One minute or more but less than 2 minutes
[0218] 2 . . . 2 minutes or more but less than 5 minutes
[0219] 1 . . . 5 minutes or more
[0220] [Color Density of Ink Images]
[0221] A solid printing was applied with a black colored ink on the
specimen.
[0222] The color density of the black colored ink images was
measured by using a Macbeth reflection color density tester (Model
RD-920). The measurement was repeated 5 times and the color density
was represented by an average value of the measured values.
[0223] [Gloss of Printed Portion]
[0224] The gloss of ink-printed portion of the specimen was
determined by observing the ink-printed portion at an angle of 20
degrees from the surface of the specimen by the-naked eye and
evaluated in the following four classes.
[0225] 4 . . . Very high gloss substantially equal to the gloss of
conventional full color-printed silver salt type photographic
printing sheets
[0226] 3 . . . High gloss but slightly lower than the gloss of the
full color printed photographic printing sheets
[0227] 2 . . . Similar to the gloss of printed coated paper
sheets
[0228] 1 . . . Similar to the gloss of printed PPC sheets
[0229] [Form of Ink Dots]
[0230] The form of the printed ink dots was observed by a
microscope at a magnification of 100 to 200.
[0231] The test results are shown in Table 1.
2 TABLE 1 Ink absorption Ink absorption Ink absorption Water Color
density Gloss of Form of ink Example No. rate capacity resistance
of ink images printed portion dots Example I-1 4 4 4 2.20 3 True
circle I-2 3 3 4 2.19 3 " I-3 4 4 3 2.19 3 " I-4 4 4 4 2.23 3 " I-5
4 4 4 2.23 3 " I-6 4 4 4 1.91 3 " I-7 4 4 4 1.70 3 " I-8 4 4 4 2.27
3 " I-9 4 4 4 2.12 3 " Comparative I-1 4 4 4 1.15 3 True circle
Example I-2 4 4 2 1.30 1 Irregular (cloud-like) I-3 4 4 2 1.21 1
Irregular (cloud-like) I-4 1 1 4 2.25 3 True cirle I-5 4 1 4 1.87 3
" I-6 1 2 4 2.06 3 " I-7 1 1 1 2.40 2 circle I-8 4 4 4 1.41 2
Irregular (cloud-like) I-9 2 4 2 2.10 2 Irregular (cloud-like)
[0232] Table 1 clearly shows that in the ink jet recording sheets
of Examples I-1 to I-9 in accordance with the present invention,
the ink-receiving layers had satisfactory ink-absorbing properties
and water resistance, the ink dots had a true circle form and the
printed ink images had a high gloss, a high color density, and
satisfactory clarity and sharpness. However, the ink jet recording
sheets of Comparative examples were unsatisfactory in one or more
of the above-tested performances.
[0233] The above-mentioned excellent properties of the ink jet
recording material of the present invention are derived from the
specific silica or aluminosilicate colloidal particles contained in
the ink-receiving layer. The secondary particles of silica or
aluminosilicate usable for the present invention each comprising a
plurality of primary particles which have a sphere form, exhibit an
enhanced film-forming property and ink-absorbing property and thus
the resultant ink-receiving layer exhibits a high resistance to
cracking and excellent ink-absorbing property and the ink images
recorded in the ink-receiving layer have high color density and
clarity.
Example Group II
Examples II-1 to II-8 and Comparative Examples II-1 to II-4
[0234] In Example Group II, the following pigments were used.
[0235] (1) Silica colloidal particles A-2
[0236] An aqueous colloidal dispersion of silica colloidal
particles A-2 having a concentration of 8% by weight was prepared
by dispersing wet method synthetic amorphous silica particles
having an average primary particle size of 13 nm and an average
secondary particle size of 2 .mu.m and available under a trademark
of Nipsil HD from Nihon Silica Kogyo K.K. in water and pulverizing
by repeating a combination of a sand grinder treatment and an
ultrasonic homogenizer treatment until the average secondary size
of the pulverized silica particles reached 40 nm.
[0237] (2) Silica colloidal particles B-2
[0238] An aqueous colloidal dispersion of silica colloidal
particles B-2 having a concentration of 12% by weight was prepared
by dispersing wet method synthetic amorphous silica particles
having an average primary particle size of 15 nm and an average
secondary particle size of 2.2 .mu.m and available under a
trademark of Nipsil K-300 from Nihon Silica Kogyo K.K. in water and
pulverizing by repeating a combination of a sand grinder treatment
and an ultrasonic homogenizer treatment until the average secondary
size of the pulverized silica particles reached 90 nm.
[0239] (3) Silica colloidal particles C-2
[0240] An aqueous colloidal dispersion of silica colloidal
particles C-2 having a concentration of 12% by weight was prepared
by dispersing wet method synthetic amorphous silica particles
having an average primary particle size of 24 nm and an average
secondary particle size of 1.5 .mu.m and available under a
trademark of Nipsil E-1011 from Nihon Silica Kogyo K.K. in water
and pulverizing by repeating a combination of a sand grinder
treatment and an ultrasonic homogenizer treatment until the average
secondary size of the pulverized silica particles reached 120
nm.
[0241] (4) Silica colloidal particles D-2
[0242] An aqueous colloidal dispersion of silica colloidal
particles D-2 having a concentration of 15% by weight was prepared
by dispersing wet method synthetic amorphous silica particles
having an average primary particle size of 13 nm and an average
secondary particle size of 2 .mu.m and available under a trademark
of Nipsil HD from Nihon Silica Kogyo K.K. in water and pulverizing
by repeating a combination of a sand grinder treatment and an
ultrasonic homogenizer treatment until the average secondary size
of the pulverized silica particles reached 240 nm.
[0243] (5) Aluminosilicate colloidal particles A
[0244] They are as mentioned above.
Example II-1
[0245] An aqueous silica colloidal coating solution having a solid
content of 8% by weight was prepared from the silica colloidal
dispersion A-2 in an amount of 100 parts by solid weight and 40
parts by weight of polyvinyl alcohol (available under the trademark
of PVA-135H, from Kuraray Co., Ltd.) having a degree of
polymerization of 3500 and a degree of saponification of 99% or
more.
[0246] A substrate sheet was prepared by laminating a surface of a
coated paper sheet (available under the trademark of OK Coat from
OJI PAPER CO., Ltd.) having a basis weight of 127.9 g/m.sup.2 with
a polyethylene resin layer having a thickness of 15 .mu.m by an
extrusion-laminating method. This polyethylene resin-laminated
paper sheet will be referred to as a laminated paper sheet
hereinafter.
[0247] The aqueous silica colloidal coating solution was coated on
a surface of the laminated paper sheet by using a Mayer bar and
dried to form an ink-receiving layer with a dry weight of 20
g/m.sup.2.
[0248] An ink jet recording sheet was obtained.
[0249] A pore radius distribution curve was prepared for the
resultant ink-receiving layer. In this curve, a peak corresponding
to a pore radius of 8 nm was found as shown in FIG. 1. The
measurement of the pore radius was carried out for the pore radius
of from 3 nm to 100 .mu.m. In this measurement, only one peak was
found at the pore radius of 8 nm.
[0250] In the ink-receiving layer, the integrated pore volume of
all the pores was about 0.86 ml/g and the total volume of the pores
having a pore radius of from 3 to 20 nm was 0.6 ml/g.
Example II-2
[0251] An ink jet recording sheet was produced by the same
procedures as in Example II-1, except that an aqueous silica
colloidal coating solution having a solid content of 12% by weight
was prepared from the silica colloidal dispersion B-2 in an amount
of 100 parts by solid weight and 40 parts by weight of the
polyvinyl alcohol (PVA-135H), and coated on the laminated paper
sheet by a Mayer bar and dried, to form an ink-receiving layer
having a dry weight of 20 g/m.sup.2. The pore radius distribution
curve of the ink-receiving layer had a peak corresponding to a pore
radius of 18 nm.
Example II-3
[0252] An ink jet recording sheet was produced by the same
procedures as in Example II-1, except that an aqueous silica
colloidal coating solution having a solid content of 12% by weight
was prepared from the silica colloidal dispersion C-2 in an amount
of 100 parts by solid weight and 40 parts by weight of the
polyvinyl alcohol (PVA-135H), and coated on the laminated paper
sheet by a Mayer bar and dried, to form an ink-receiving layer
having a dry weight of 20 g/m.sup.2. The pore radius distribution
curve of the resultant ink-receiving layer had two peaks
corresponding to pore radiuses of 4 nm and 35 nm. The ink-receiving
layer had an integrated pore volume of 1.1 ml/g and a total volume
of the pores having a pore radius of 3 to 20 nm of 0.6 ml/g.
Example II-4
[0253] An ink jet recording sheet was produced by the same
procedures as in Example II-1, except that an aqueous
aluminosilicate colloidal coating solution having a solid content
of 8% by weight was prepared from the aluminosilicate colloidal
dispersion A in an amount of 100 parts by solid weight and 40 parts
by weight of the polyvinyl alcohol (PVA-135H), and coated on the
laminated paper sheet by a Mayer bar and dried, to form an
ink-receiving layer having a dry weight of 20 g/m.sup.2. The pore
radius distribution curve of the resultant ink-receiving layer had
a peak corresponding to a pore radius of 10 nm.
Example II-5
[0254] An ink jet recording sheet was produced by the same
procedures as in Example II-1, except that an aqueous silica
colloidal coating solution having a solid content of 8% by weight
was prepared from the silica colloidal dispersion A-2 in an amount
of 100 parts by solid weight and 40 parts by weight of the
polyvinyl alcohol (PVA-135H), and coated on a surface of a shaping
base consisting of a polyethylene terephthalate (PET) film having a
thickness of 75 .mu.m and a surface roughness of 0.02 .mu.m
(trademark: Lumilar T, made by Toray Industries, Inc.) by a Mayer
bar and dried, to form a coating layer corresponding to an
ink-receiving layer and having a dry weight of 20 g/m.sup.2.
[0255] Separately, a surface of the laminated paper sheet was
coated with an acrylic ester adhesive (trademark: A-02, made by
Nippon Carbide Industries Co., Inc.) and dried to form an
intermediate layer in a dry amount of 10 g/m.sup.2.
[0256] Then, the intermediate layer of the laminated paper sheet
was superposed on and press-bonded to the coating layer on the
shaping base under a linear pressure of 20 kg/cm by using a
calender. The resultant laminate was separated from the shaping
base, to provide an ink jet recording sheet. The pore radius
distribution curve of the ink-receiving layer had a peak
corresponding to a pore radius of 8 nm.
Example II-6
[0257] An ink jet recording sheet was produced by the same
procedures as in Example II-1, except that an aqueous silica
colloidal coating solution having a solid content of 8% by weight
was prepared from the silica colloidal dispersion A-2 in an amount
of 100 parts by solid weight and 40 parts by weight of the
polyvinyl alcohol (PVA-135H), and coated on a surface of the same
shaping base as in Example II-5 by a Mayer bar and dried, to form a
coating layer corresponding to an ink-receiving layer having a dry
weight of 10 g/m.sup.2.
[0258] On the coating layer on the shaping base, an aqueous silica
colloidal coating solution prepared from the silica colloidal
dispersion B-2 in an amount of 100 parts by solid weight and the
polyvinyl alcohol (PVA-135H) in an amount of 40 parts by solid
weight and having a solid content of 12% by solid weight was coated
by using a Mayer bar and dried, to form an additional coating layer
corresponding to an additional ink-absorbent layer and having a dry
weight of 20 g/m.sup.2.
[0259] Separately, a surface of the laminated paper sheet was
coated with an acrylic ester adhesive (trademark: A-02, made by
Nihon Carbide Kogyo K.K.) and dried to form an intermediate layer
in a dry amount of 10 g/m.sup.2.
[0260] Then, the intermediate layer of the laminated paper sheet
was superposed on and press-bonded to the additional coating layer
of the shaping base under a linear pressure of 20 kg/cm by using a
calender. The resultant laminate was separated from the shaping
base, to provide an ink jet recording sheet. The pore radius
distribution curve of the ink-receiving layer had a peak
corresponding to a pore radius of 8 nm.
Example II-7
[0261] An ink jet recording sheet was produced by the same
procedures as in Example II-1, except that an aqueous silica
colloidal coating solution having a solid content of 8% by weight
was prepared from the silica colloidal dispersion A-2 in an amount
of 100 parts by solid weight and 40 parts by weight of the
polyvinyl alcohol (PVA-135H), and coated on the surface of the same
shaping base as in Example II-5 by a Mayer bar and dried, to form a
coating layer corresponding to an ink-receiving layer having a dry
weight of 20 g/m.sup.2 On the surface of the coating layer formed
on the shaping base, an aqueous silica dispersion prepared from 100
parts by solid weight of wet method synthetic amorphous silica
particles having an average primary particle size of about 15 nm
and an average secondary particle size of 4.5 .mu.m (available
under a trademark of Finesil X-45, from Tokuyama Corp.) and 40
parts by solid weight of a polyvinyl alcohol having a degree of
polymerization of 1800 and a degree of saponification of 98.5%
(available under a trademark of PVA-117, from Kuraray Co., Ltd.),
and having a solid content of 15% by weight, was coated by using a
Mayer bar and dried, to form an additional coating layer
corresponding an additional ink-absorbent layer, having a dry
weight of 10 g/m.sup.2.
[0262] Separately, a surface of the laminated paper sheet was
coated with an acrylic ester adhesive (trademark: A-02, made by
Nihon Carbide Kogyo K.K.) and dried to form an intermediate layer
in a dry amount of 10 g/m.sup.2.
[0263] Then, the intermediate layer of the laminated paper sheet
was superposed on and press-bonded to the additional coating layer
of the shaping base under a linear pressure of 20 kg/cm by using a
calender. The resultant laminate was separated from the shaping
base, to provide an ink jet recording sheet. The pore radius
distribution curve of the ink-receiving layer had a peak
corresponding to a pore radius of 8 nm.
Example II-8
[0264] An ink jet recording sheet was produced by the following
procedures. An aqueous silica colloidal coating solution having a
solid content of 12% by weight was prepared from the silica
colloidal dispersion D-2 in an amount of 100 parts by solid weight
and 40 parts by weight of the polyvinyl alcohol (PVA-135H), and
coated on the laminated paper sheet by a Mayer bar and dried, to
form an ink-receiving layer having a dry weight of 20 g/m.sup.2.
The pore radius distribution curve of the ink-receiving layer had a
peak corresponding to a pore radius of 45 nm.
Comparative Example II-1
[0265] An ink jet recording sheet was produced by the same
procedures as in Example II-1, except that an aqueous silica
coating solution having a solid content of 15% by weight was
prepared from wet method synthetic amorphous silica particles
having an average primary particle size of about 15 nm and an
average secondary particle size of 4.5 .mu.m (trademark: Finesil
X-45, Tokuyama Corp.) in an amount of 100 parts by solid weight and
40 parts by weight of a polyvinyl alcohol having a degree of
polymerization of 1800 and a degree of saponification of 98.5%
(trademark: PVA-117, made by Kuraray Co., Ltd.), and coated on the
laminated paper sheet by a Mayer bar and dried, to form an
ink-receiving layer having a dry weight of 20 g/m.sup.2. The pore
radius distribution curve of the ink-receiving layer had three
peaks corresponding to pore radiuses of 5 nm, 0.32 .mu.m and 1.4
.mu.m. In the ink-receiving layer, the integrated pore volume of
all the pore was 0.75 ml/g and the total volume of pores having a
pore radius of 4 to 20 nm was 0.09 ml/g.
Comparative Example II-2
[0266] An ink jet recording sheet was produced by the same
procedures as in Example II-1, except that an aqueous
pseudoboehmite dispersion having a solid content of 5% by weight
was prepared from a pseudoboehmite sol having an average primary
particle size of 10 nm.times.100 nm (trademark: AS-520, made by
Nissan Kagakukogyo K.K.) in an amount of 100 parts by solid weight
and 10 parts by weight of the polyvinyl alcohol (PVA-135H), and
coated on the laminated paper sheet by a Mayer bar and dried, to
form an ink-receiving layer having a dry weight of 20 g/m.sup.2.
The pore radius distribution curve of the resultant ink-receiving
layer had a peak corresponding to a pore radius of 7 nm.
Comparative Example II-3
[0267] An ink jet recording sheet was produced by the same
procedures as in Example II-1, except that an aqueous silica
colloidal coating solution having a solid content of 15% by weight
was prepared from an anionic primary colloidal silica particles
having an average primary particle size of 80 nm (trademark:
Snowtex ZL, made by Nissan Kagakukogyo K.K.) in an amount of 100
parts by solid weight and 10 parts by weight of the polyvinyl
alcohol (PVA-135H), and coated on the laminated paper sheet by a
Mayer bar and dried, to form an ink-receiving layer having a dry
weight of 20 g/m.sup.2. The pore radius distribution curve of the
ink-receiving layer had a peak corresponding to a pore radius of 13
nm.
Comparative Example II-4
[0268] A gloss ink jet recording sheet having an ink-fixing layer
and a gloss layer (available under the trademark of GP-101 from
Canon Corp.) was subjected to the following tests. The ink-fixing
layer exhibited a pore radius distribution curve having a peak
corresponding to a pore radius of 5 .mu.m.
[0269] Tests
[0270] Specimens of the ink jet recording sheets of Examples II-1
to II-8 and Comparative Examples II-1 to II-4 were subjected to the
following tests for water resistance, the gloss, the ink-absorbing
rate and ink-absorption capacity of the ink-receiving layer.
[0271] These specimens except for the specimen of Comparative
Examples II-4 were surface-smoothed by using a super calender under
a linear pressure of 70 kg/cm, before the tests.
[0272] The gloss and ink-absorption properties were tested by solid
printing the specimens of the ink jet recording sheets by a
practical ink jet printer (trademark: BJC-610J, made by Canon
Corp., 720 dpi.times.729 dpi) and the gloss, the ink-absorption
properties and color density of the solid printed ink images were
measured.
[0273] [Water Resistance]
[0274] The test for water resistance was the same as in Example
Group I.
[0275] [Ink Absorption]
[0276] The test for ink-absorbing rate was the same as in Example
Group I.
[0277] In the test for the ink absorption capacity, the surfaces of
the specimens were solid printed with a black-colored ink in an
ink-jetting amount of 30 g/m.sup.2.
[0278] [Color density]
[0279] The test for color density of the printed ink images was the
same as in Example Group I.
[0280] [Gloss]
[0281] The test for gloss of the ink-printed portion of the ink jet
recording sheet was the same as in Example Group I.
[0282] The test results are shown in Table 2.
3 TABLE 2 Pore radius Ink-absorption corresponding to Ink-absorbing
Ink-absorption Water Gloss of peak in pore radius Example No. rate
capacity resistance Color density printed portion distribution
curve Example II-1 4 3 4 2.20 3 8 nm II-2 4 3 4 1.99 3 18 nm II-3 4
3 4 1.85 3 4, 35 nm II-4 4 3 4 2.12 3 10 nm II-5 4 3 4 2.25 4 8 nm
II-6 4 4 4 2.22 4 8 nm II-7 4 4 4 2.19 3 8 nm II-7 4 3 4 1.70 3 45
nm Comparative II-1 4 3 2 1.27 1 5 nm Example 0.32 .mu.m 1.40 .mu.m
II-2 2 1 4 2.21 3 7 nm II-3 4 1 4 1.85 3 13 nm II-4 4 3 4 1.41 2 5
.mu.m
[0283] Table 2 clearly shows that in Examples II-1 to II-8 in
accordance with the present invention, the resultant ink jet
recording materials had a high ink-absorbing rate and a high
ink-absorption capacity and could receive thereon ink images having
a high gloss, color density, clarity and sharpness.
Example Group III
Examples III-1 to III-9 and Comparative Examples III-1 to III-3
[0284] In Example Group III, the following pigments were
employed.
[0285] (1) Silica colloidal particles A-3
[0286] An aqueous colloidal dispersion of silica colloidal
particles A-3 having a concentration of 8% by solid weight was
prepared by dispersing wet method synthetic amorphous silica
particles having an average primary particle size of 15 nm and an
average secondary particle size of 2.2 .mu.m and available under a
trademark of Nipsil K-300 from Nihon Silica Kogyo K.K. in water and
pulverizing by repeating a combination of a sand grinder treatment
and an ultrasonic homogenizer treatment until the average secondary
size of the pulverized silica particles reached 40 nm.
[0287] (2) Silica colloidal particles B-3
[0288] An aqueous colloidal solution of silica colloidal particles
B-3 having a concentration of 12% by solid weight was prepared by
dispersing wet method synthetic amorphous silica particles having
an average primary particle size of 24 nm and an average secondary
particle size of 2.5 .mu.m and available under a trademark of
Nipsil E-220A from Nihon Silica Kogyo K.K. in water and pulverizing
by repeating a combination of a sand grinder treatment and an
ultrasonic homogenizer treatment until the average secondary size
of the pulverized silica particles reached 80 nm.
[0289] (3) Silica colloidal particles C-3
[0290] An aqueous colloidal solution of silica colloidal particles
C-3 having a concentration of 12% by solid weight was prepared by
dispersing the same synthetic amorphous silica particles as for the
silica colloidal particles B-3 in water and pulverizing by
repeating a combination of a sand grinder treatment and an
ultrasonic homogenizer treatment until the average secondary size
of the pulverized silica particles reached 150 nm.
[0291] (4) Silica colloidal particles D-3
[0292] An aqueous colloidal dispersion of silica colloidal
particles D-3 having a concentration of 12% by weight was prepared
by dispersing the same synthetic amorphous silica particles as for
the silica colloidal particles A-3 in water and pulverizing by
repeating a combination of a sand grinder treatment and an
ultrasonic homogenizer treatment until the average secondary size
of the pulverized silica particles reached 190 nm.
[0293] (5) Silica colloidal particles E-3
[0294] An aqueous colloidal solution of silica colloidal particles
E-3 having a concentration of 15% by weight was prepared by
dispersing wet method synthetic amorphous silica particles having
an average primary particle size of 30 nm and an average secondary
particle size of 3 .mu.m and available under a trademark of Nipsil
E-170 from Nihon Silica Kogyo K.K. in water and pulverizing by
repeating a combination of a sand grinder treatment and an
ultrasonic homogenizer treatment until the average secondary size
of the pulverized silica particles reached 240 nm.
[0295] (6) Aluminosilicate particle A
[0296] This is the same as in Example Group I.
Example III-1
[0297] An aqueous silica colloidal coating solution having a solid
content of 8% by weight was prepared from the silica colloidal
dispersion A-3 in an amount of 100 parts by solid weight and a
polyvinyl alcohol having a degree of polymerization of 2400 and a
degree of saponification of 98.5% or more (trademark: PVA-124, made
by Kuraray Co., Ltd.).
[0298] A substrate sheet was prepared by laminating a surface of a
coated paper sheet (trademark: OK Coat, made by OJI PAPER CO. Ltd.)
having a basis weight of 127.9 g/m.sup.2, with a polyethylene resin
layer having a thickness of 15 .mu.m by an extrusion-laminating
method. This polyethylene resin-laminated paper sheet will be
referred to as a laminated paper sheet hereinafter.
[0299] The aqueous coating solution was coated on a surface of the
laminated paper sheet by using a Mayer bar and dried to form an
ink-receiving layer with a dry weight of 15 g/m.sup.2.
[0300] An ink jet recording sheet was obtained.
Example III-2
[0301] An ink jet recording sheet was prepared by the same
procedures as in Example III-1, except that an aqueous silica
colloidal coating solution having a solid content of 12% by weight
was prepared from the silica colloidal dispersion B-3 in an amount
of 100 parts by solid weight and a polyvinyl alcohol having a
degree of polymerization of 3500 and a degree of saponification of
99% or more (trademark: PVA-135, made by Kuraray Co., Ltd.) in an
amount of 25 parts by solid weight, and coated on the laminated
paper sheet by using a Mayer bar and dried to form an ink-receiving
layer having a dry weight of 15 g/m.sup.2.
Example III-3
[0302] An ink jet recording sheet was prepared by the same
procedures as in Example III-1, except that an aqueous silica
colloidal coating solution having a solid content of 12% by weight
was prepared from the silica colloidal dispersion C-3 in an amount
of 100 parts by solid weight and the polyvinyl alcohol (PVA-124) in
an amount of 50 parts by solid weight, and coated on the laminated
paper sheet by using a Mayer bar and dried to form an ink-receiving
layer having a dry weight of 15 g/m.sup.2.
Example III-4
[0303] An ink jet recording sheet was prepared by the same
procedures as in Example III-1, except that in the preparation of
the an aqueous silica colloidal coating solution having a solid
content of 12% by weight, the silica colloidal dispersion A-3 was
replaced by the silica colloidal dispersion D-3.
Example III-5
[0304] An ink jet recording sheet was prepared by the same
procedures as in Example III-1, except that an aqueous
aluminosilicate colloidal coating solution having a solid content
of 8% by weight was prepared from the aluminosilicate colloidal
dispersion A in an amount of 100 parts by solid weight and the
polyvinyl alcohol (PVA-124) in an amount of 40 parts by solid
weight, and coated on the laminated paper sheet by using a Mayer
bar and dried to form an ink-receiving layer having a dry weight of
15 g/m.sup.2.
Example III-6
[0305] An ink jet recording sheet was prepared by the same
procedures as in Example III-1, except that an aqueous silica
colloidal coating solution having a solid content of 8% by weight
was prepared from the silica colloidal dispersion A-3 in an amount
of 100 parts by solid weight and the polyvinyl alcohol (PVA-124) in
an amount of 40 parts by solid weight, and coated on a surface of a
shaping base consisting of a polyethylene terephthalate film
(trademark: Lumilar T, made by Toray) having a thickness of 75
.mu.m and a surface roughness Ra of 0.02 .mu.m by using a Mayer
bar, and dried to form a coating layer corresponding to an
ink-receiving layer, having a dry weight of 15 g/m.sup.2.
[0306] Separately, a surface of the laminated paper sheet was
coated with an acrylic acid adhesive (trademark: A-02, made by
Nihon Carbide Kogyo K.K.) and dried, to form an intermediate layer
having a dry weight of 10 g/m.sup.2.
[0307] The intermediate layer on the laminated paper sheet was
superposed on and press-bonded to the coating layer formed on the
shaping base under a linear pressure of 20 kg/cm by using a
calender. Then the shaping base film was removing from the
resultant laminate to leave an ink jet recording sheet.
Example III-7
[0308] An ink jet recording sheet was prepared by the same
procedures as in Example III-1, except that an aqueous silica
colloidal coating solution having a solid content of 8% by weight
was prepared from the silica colloidal dispersion A-3 in an amount
of 100 parts by solid weight and the polyvinyl alcohol (PVA-124) in
an amount of 70 parts by solid weight, and coated on the laminated
paper sheet by using a Mayer bar and dried to form an ink-receiving
layer having a dry weight of 15 g/cm.sup.2.
Example III-8
[0309] An ink jet recording sheet was prepared by the same
procedures as in Example III-1, except that an aqueous silica
colloidal coating solution having a solid content of 15% by weight
was prepared from the silica colloidal dispersion E-3 in an amount
of 100 parts by solid weight and the polyvinyl alcohol (PVA-124) in
an amount of 40 parts by solid weight, and coated on the laminated
paper sheet by using a Mayer bar and dried to form an ink-receiving
layer having a dry weight of 15 g/m.sup.2.
Example III-9
[0310] An ink jet recording sheet was prepared by the same
procedures as in Example III-1, except that the same aqueous silica
colloidal coating solution as in Example III-2 was coated on the
laminated paper sheet by using a Mayer bar and dried to form an
additional ink-absorbent layer having a dry weight of 10 g/m.sup.2.
Then, the same aqueous silica colloidal solution as in Example
III-1 was coated on the additional ink-absorbent layer to form an
ink-receiving layer having a dry weight of 10 g/m.sup.2.
Comparative Example III-1
[0311] An ink jet recording sheet was prepared by the same
procedures as in Example III-1, except that an aqueous silica
coating solution having a solid content of 15% by weight was
prepared from a wet method synthetic amorphous, silica particles
(trademark: Finesil x-45, made by Tokuyama K.K.) having an average
primary particle size of about 15 nm and an average secondary
particle size of 4.5 .mu.m in an amount of 100 parts by solid
weight and a polyvinyl alcohol having a degree of polymerization of
1800 and a degree of saponification of 98.5% (trademark: PVA-117,
made by Kuraray Co., Ltd.) in an amount of 30 parts by solid
weight, and coated on the laminated paper sheet by using a Mayer
bar and dried to form an ink-receiving layer having a dry weight of
15 g/m.sup.2.
Comparative Example III-2
[0312] An ink jet recording sheet was prepared by the same
procedures as in Example III-1, except that an aqueous
pseudoboehmite coating dispersion having a solid content of 5% by
weight was prepared from a pseudoboehmite sol primary particle
dispersion (trademark: AS-520, made by Nissan Kagakukogyo K.K.)
having an average primary particle size of 10 nm to 100 nm in an
amount of 100 parts by solid weight and the same polyvinyl alcohol
(PVA-117) as in Comparative Example III-1 in an amount of 10 parts
by solid weight, and coated on the laminated paper sheet by using a
Mayer bar and dried to form an ink-receiving layer having a dry
weight of 15 g/m.sup.2.
Comparative Example III-3
[0313] An ink jet recording sheet was prepared by the same
procedures as in Example III-1, except that an aqueous colloidal
silica coating solution having a solid content of 15% by weight was
prepared from a colloidal silica primary particle dispersion
(trademark: Snowtex 30, made by Nissan Kagakukogyo K.K.) having an
average primary particle size of 15 nm in an amount of 50 parts by
solid weight and the polyvinyl alcohol (PVA-117) in an amount of
100 parts by solid weight, and coated on the laminated paper sheet
by using a Mayer bar and dried to form an ink-receiving layer
having a dry weight of 15 g/m.sup.2.
Comparative Example III-4
[0314] A practical gloss ink jet recording sheet (trademark:
KH-101, made by Canon Corp.) having an ink-fixing layer formed on a
substrate sheet and comprising amorphous silica secondary particles
having a large secondary particle size of 1 Mm or more and a gloss
layer formed on the ink-fixing layer and comprising colloidal
silica primary particles was subjected to the following tests.
[0315] Tests
[0316] The tests were carried out in the same manner as in Example
Group II, with the following exceptions.
[0317] In the test of the ink absorption capacity, the
black-colored ink was solid printed in an ink jetting amount of 18
g/m.sup.2. The haze volume test was carried out in the same manner
as mentioned above, except that an ink-receiving layer was coated
on a transparent substrate film (trademark: Lumilar T, thickness:
75 .mu.m) and the haze value was measured by using a reflection
color density meter (Model: HR-100, made by Murakami
Shikisaigijitsu Kenkyusho). Also, in Example III-9, the ink
receiving layer and the additional ink-absorbent layer laminated on
each other exhibited a total haze value of 41%.
[0318] The test results are shown in Table 3.
4 TABLE 3 Gloss of Ink-absorption solid Haze value Smoothness
Content of Ink-absorbing Ink-absorption Water Color printed
(*).sub.1 (*).sub.2 pigment Example No. rate capacity resistance
density portion (%) (sec/10 ml) (wt %) Example III-1 4 4 4 2.32 3-4
9 12000 71 III-2 4 4 4 1.99 3 36 4200 80 III-3 4 4 4 1.87 3 51 2700
67 III-4 4 4 4 1.79 3 60 1800 71 III-5 4 4 4 2.14 3 18 9800 71
III-6 4 4 4 2.37 4 10 41000 71 III-7 3 3 4 2.35 3 8 13000 59 III-8
4 4 4 1.70 3 65 1200 71 III-9 4 4 4 2.17 3 8 1100 76 Comparative
III-1 4 4 2 1.27 1 85 25 77 Example III-2 2 1 4 2.29 3-4 8 13000 91
III-3 1 1 1 2.45 2 3.5 -- 67 III-4 4 4 4 1.48 2 -- 520 -- Note
(*).sub.1Haze value was of the ink receiving layer (*).sub.2Bekk
smoothness was determined in accordance with JIS P8119.
[0319] Table 3 shows that the ink jet recording sheets of Examples
III-1 to III-9 in accordance with the present invention exhibited
satisfactory ink-absorption properties, the ink receiving layer
exhibited high water resistance, and smoothness and the solid
printed ink images had a satisfactory gloss, and a high color
density.
Example Group IV
Examples IV-1 to IV-15 and Comparative Examples IV-1 to IV-2
[0320] In Example Group IV, the coating amount was indicated by a
corresponding dry coating weight. The water content of an ink
receiving layer was indicated by a weight % of water based on the
absolute dry weight of the ink receiving layer. For example, when
an ink receiving layer consisted of 100g of an absolute dry solid
and 8g of water, the water content of the ink receiving layer was
8% by weight. Usually, the dry ink receiving layer had a water
content of about 8% by weight.
[0321] Also, in Example Group IV, the following pigments were
employed.
[0322] (1) Silica colloidal particles A-4
[0323] An aqueous colloidal solution of silica colloidal particles
A-4 having a concentration of 8% by weight was prepared by
dispersing wet method synthetic amorphous silica particles having
an average primary particle size of 14 nm and an average secondary
particle size of 2.4 .mu.m and available under a trademark of
Mizukasil P-802 from Mizusawa Kagakukogyo K.K. in water and
pulverizing by repeating a combination of a sand grinder treatment
and an ultrasonic homogenizer treatment until the average secondary
size of the pulverized silica particles reached 70 nm.
[0324] (2) Silica colloidal particles B-4
[0325] An aqueous colloidal solution of silica colloidal particles
B-4 having a concentration of 12% by weight was prepared by
dispersing wet method synthetic amorphous silica particles having
an average primary particle size of 15 nm and an average secondary
particle size of 2.2 .mu.m and available under a trademark of
Mizukasil C-212 from Mizusawa Kagakukogyo K.K. in water and
pulverizing by repeating a combination of a sand grinder treatment
and an ultrasonic homogenizer treatment until the average secondary
particle size of the pulverized silica particles reached 200
nm.
[0326] (3) Aluminosilicate colloidal particles B
[0327] An aqueous aluminum silicate colloidal dispersion B having a
solid content of 10% by dry weight, was prepared by dispersing
synthetic aluminosilicate secondary agglomeration (trademark:
Kyowaad 700, made by Kyowa Chemical Industries Co., Ltd.) having an
average primary particle size of 3 to 40 nm and an average
secondary particle size of 10 .mu.m in water, and pulverizing by
repeating a combination of a sand grinder treatment and an
ultrasonic homogenizer treatment until the average secondary
particle size reached 150 nm.
Example IV-1
[0328] An aqueous colloidal silica coating solution having a solid
content of 8% by weight was produced from the silica colloidal
solution A-4 in an amount of 100 parts by solid weight, and a
polyvinyl alcohol (trademark: PVA-124, made by Kuraray Co., Ltd.)
having a degree of polymerization of 2400 and a degree of
saponification of 98.5% in an amount of 50 parts by solid weight,
and coated on a surface of a shaping base consisting of a
polyethylene terephthalate film (trademark: Lumilar T, made by
Toray Industries Inc.) having a thickness of 75 .mu.m and a surface
roughness Ra of 0.02 .mu.m to form a coating layer corresponding to
an ink-receiving layer and having a dry weight of 15 g/m.sup.2.
[0329] A synthetic paper sheet (trademark: Yupo FPG 80, made by Oji
Yuka Goseishi K.K.) having a basis weight of 60 g/m.sup.2) was
superposed on and press-bonded to the coating layer formed on the
shaping base at a temperature of 75.degree. C. under a linear
pressure of 50 kg/cm by using a calender. Then, the resultant
laminate was separated from the shaping base film, to obtain an ink
jet recording sheet.
Example IV-2
[0330] An aqueous colloidal silica coating solution having a solid
content of 8% by weight was produced from the silica colloidal
solution B-4 in an amount df 100 parts by solid weight, and a
polyvinyl alcohol (trademark: PVA-135H, made by Kuraray Co., Ltd.)
having a degree of polymerization of 3500 and a degree of
saponification of 99% or more in an amount of 50 parts by solid
weight, and coated on a surface of a synthetic paper sheet
(trademark: Yupo FPG 80, made by Oji Yuka Goseishi) having a basis
weight of 60 g/m.sup.2, and dried, to form an under coating layer
for an additional ink-absorbent layer having a dry weight of 15
g/m.sup.2.
[0331] Separately, an aqueous silica colloidal coating solution
having a solid content of 8% by weight was prepared from 100 parts
by solid weight of the silica colloidal dispersion A-4 and 50 parts
by solid weight of the polyvinyl alcohol (PVA-135H), and coated on
a surface of the same shaping base film as in Example IV-1 to form
a coating layer corresponding to an ink-receiving layer and having
a dry weight of 15 g/m.sup.2.
[0332] The undercoating layer on the synthetic paper sheet was
superposed on and press-bonded to the coating layer formed on the
shaping base at a temperature of 75.degree. C. under a linear
pressure of 50 kg/cm by using a calender. Then, the resultant
laminate was separated from the shaping base film, to obtain an ink
jet recording sheet.
Example IV-3
[0333] An aqueous colloidal silica coating solution having a solid
content of 8% by weight was produced from the silica colloidal
dispersion A-4 in an amount of 100 parts by solid weight, and the
polyvinyl alcohol (PVA-135H) in an amount of 50 parts by solid
weight, and coated on a surface of the same shaping base film as in
Example IV-1 to form a coating layer corresponding to an outermost
ink-receiving layer and having a dry weight of 15 g/m.sup.2.
[0334] The same ink jet recording sheet as in Example IV-1 composed
of the synthetic paper sheet and the ink jet receiving layer
laminated on the synthetic paper sheet was superposed on and
press-bonded to the coating layer formed on the shaping base so
that the ink receiving layer on the synthetic paper sheet is
brought into contact with the coating layer on the shaping base
film at a temperature of 75.degree. C. under a linear pressure of
50 kg/cm by using a calender. Then, the resultant laminate was
separated from the shaping base film, to obtain an ink jet
recording sheet.
Example IV-4
[0335] An aqueous colloidal silica coating solution having a solid
content of 8% by weight was produced from the silica colloidal
dispersion A-4 in an amount of 100 parts by solid weight, and the
polyvinyl alcohol (PVA-135H) in an amount of 50 parts by solid
weight, and coated on a surface of the same synthetic paper sheet
(Yupo FPG-80) as in Example IV-2 to form an undercoating coating
layer corresponding to an additional ink-absorbent layer and having
a dry weight of 15 g/m.sup.2.
[0336] Separately, an aqueous colloidal silica coating solution
having a solid content of 8% by weight was prepared from 100 parts
by solid weight of the silica colloidal dispersion A-4 and 50 parts
by solid weight of the polyvinyl alcohol (PVA-135H), and coated on
a surface of the same shaping base film (Lumilar T) as in Example
IV-1, to form a coating layer corresponding to an ink-receiving
layer and having a dry weight of 15 g/m.sup.2.
[0337] The undercoat layer formed on the synthetic paper sheet was
wetted with water in an amount of 3 g/m.sup.2 by using a Mayer
bar.
[0338] The water-wetted undercoating layer on the synthetic paper
sheet was superposed on and press-bonded to the coating layer on
the shaping base film by using a calender at a temperature of
75.degree. C. under a linear pressure of 50 kg/cm. The resultant
laminate was separated from the shaping base film to obtain an ink
jet recording sheet.
Example IV-5
[0339] An ink jet recording sheet was produced by the same
procedures as in Example IV-1, except that the shaping base film
was replaced by a shaping metal drum having chromium-plated and a
mirror-finished peripheral surface with a surface roughness Ra of
0.05 .mu.m.
[0340] The synthetic paper sheet (Yupo FPG80) was superposed on and
press-bonded to the coating layer formed on the shaping drum under
a linear pressure of 50 kg/cm, and the resultant laminate was
separated from the shaping drum surface, to provide an ink jet
recording sheet.
Example IV-6
[0341] An ink jet recording sheet was produced by the same
procedures as in Example IV-1, except that the silica colloidal
dispersion A-4 was replaced by the silica colloidal dispersion
B-4.
Example IV-7
[0342] An ink jet recording sheet was produced by the same
procedures as in Example IV-1, except that the polyvinyl alcohol
(PVA-124) was replaced by another polyvinyl alcohol (trademark:
PVA-117, made by Kuraray Co., Ltd.) having a degree of
polymerization of 1800.
Example IV-8
[0343] An ink jet recording sheet was produced by the same
procedures as in Example IV-1, except that the polyvinyl alcohol
(PVA-124) was replaced by another polyvinyl alcohol (trademark:
PVA-140H, made by Kuraray Co., Ltd.) having a degree of
polymerization of 4000.
Example IV-9
[0344] An ink jet recording sheet was produced by the same
procedures as in Example IV-1, except that the silica colloidal
dispersion A-4 was replaced by the aluminosilicate colloidal
dispersion B.
Example IV-10
[0345] An ink jet recording sheet was produced by the same
procedures as in Example IV-1, except that the aqueous
aluminosilicate colloidal coating solution was prepared from 100
parts by solid weight of the aluminosilicate colloidal dispersion B
and 3 parts by solid weight of a
polyethylene-polyamine-dicyandiamide condensation reaction product
(trademark: PAP-1, made by Nihon Senkakogyo K.K.).
Example IV-11
[0346] An ink jet recording sheet was produced by the same
procedures as in Example IV-1, except that the synthetic paper
sheet (Yupo FPG 80) was replaced by a laminated paper sheet
produced by extrusion-laminating a coated paper sheet (trademark:
OK Coat, made by Oji Paper Co.) having a basis weight of 127.9
g/m.sup.2 with a polyethylene resin layer with a thickness of 20
.mu.m.
Example IV-12
[0347] An aqueous silica colloidal coating solution having a solid
content of 8% by weight was prepared from the silica colloidal
dispersion A-4 in an amount of 100 parts by solid weight and 40
parts by weight of polyvinyl alcohol (available under the trademark
of PVA-140H, from Kuraray Co., Ltd.) having a degree of
polymerization of 4000 and a degree of saponification of 99% or
more.
[0348] The aqueous silica colloidal coating solution was coated on
a surface of a shaping base consisting of a polyethylene
terephthalate film (Lumilar T) having a thickness of 38 .mu.m and a
surface roughness Ra of 0.02 .mu.m, and dried, to form a coating
layer having a dry weight of 15 g/m.sup.2.
[0349] The same aqueous silica colloidal coating solution as
mentioned above was coated on a surface of the laminated paper
sheet and dried to form an additional ink-absorbent layer having a
dry weight of 15 g/m.sup.2. The additional ink-absorbent layer was
exposed to water vapor to absorb therein water in an amount of 7.5
g/m.sup.2, namely to a water content of 50% by weight.
[0350] The water-absorbed additional ink-absorbent layer on the
laminated paper sheet was superposed on and press-bonded to the
coating layer formed on the shaping base film at a temperature of
50.degree. C. under a linear pressure of 50 kg/cm by using a
calender. Then, the resultant laminate was removed from the shaping
base film, to provide an ink jet recording sheet.
Example IV-13
[0351] An aqueous silica colloidal coating solution having a solid
content of 8% by weight was prepared from 100 parts by solid weight
of the silica colloidal dispersion A-4 and 50 parts by solid weight
of the same polyvinyl alcohol (PVA-124) as in Example IV-1, and
coated on a surface of the same synthetic paper sheet (Yupo FPG-80)
as in Example IV-1 by using a Mayer bar and dried, to form an
ink-receiving layer having a dry weight of 15 g/m.sup.2.
Example IV-4
[0352] An aqueous silica colloidal coating solution having a solid
content of 8% by weight was produced from 100 parts by solid weight
of the silica colloidal dispersion A-4 and 50 parts by solid weight
of the same polyvinyl alcohol (PVA-124) as in Example IV-1, and
coated on a surface of a wood-free paper sheet having a basis
weight of 127 g/m.sup.2 to form a coating layer having a dry
coating weight of 15 g/m.sup.2.sub.1 and incompletely dried to such
an extent that the dried coating layer had a water content of about
60% by weight.
[0353] A polyethylene terephthalate film (trademark: Lumilar T made
by Toray) having a thickness of 75 .mu.m and a surface roughness of
0.02 .mu.m was superposed on the incompletely dried coating layer
on the paper sheet under pressure, and the laminate was completely
dried. The polyethylene terephthalate film was removed from the
dried laminate, to provide an ink jet recording sheet.
Example IV-15
[0354] An aqueous silica colloidal coating solution having a solid
content of 8% by weight was prepared from 100 parts by solid weight
of the silica colloidal dispersion A-4 and 50 parts by solid weight
of the polyvinyl alcohol (PVA-124) as in Example IV-1, and coated
on a surface of a shaping base consisting of the same polyethylene
terephthalate film (Lumilar T) in Example IV-1, and dried to form a
coating layer corresponding to an ink-receiving layer and having a
dry weight of 8 g/m.sup.2.
[0355] Separately, an aqueous aluminosilicate colloidal coating
solution having a solid content of 10% by weight was prepared from
100 parts by solid weight of the aluminosilicate colloidal
dispersion B and 50 parts by solid weight of polyvinyl alcohol
(PVA-117), and coated on a surface of a wood-free paper sheet
having a basis weight of 127 g/m.sup.2 by using a Mayer bar, to
form a non-dried coating layer corresponding to an additional
ink-absorbent layer and having a dry weight of 7 g/m.sup.2.
[0356] The non-dried coating layer on the paper sheet was
superposed on the coating layer on the shaping base film under
pressure, and dried (in accordance with a wet-laminating method).
Then the shaping base film was separated from the resultant
laminate.
[0357] An ink jet recording sheet was obtained.
Comparative Example IV-1
[0358] An aqueous solution of 10% by solid weight of a polyvinyl
alcohol (trademark: PVA-117, made by Kuraray Co., Ltd.) was coated
on a surface of the same laminated paper sheet as in Example IV-11,
and dried to form an ink-receiving layer having a dry weight of 10
g/m.sup.2.
[0359] An ink jet recording sheet was obtained.
Comparative Example IV-2
[0360] A practical ink jet recording gloss sheet (trademark:
GP-101, supplied by Canon Corp.) was subjected to the following
tests.
[0361] Tests
[0362] The ink jet recording sheets of Examples IV-1 to IV-15 and
Comparative Examples IV-1 and IV-2 were carried out to the same
water resistance, ink absorption, color density and gloss tests as
in Example Group I and the following coating layer bonding strength
and smoothness tests.
[0363] In the measurement of the ink absorption capacity of the ink
receiving layer, yellow-, magenta-, and cyan- colored inks were
successively solid printed in a total amount of 25 g/m.sup.2 on a
square area of 10 cm.times.10 cm of the ink receiving layer.
[0364] [Coating Layer Bonding Strength]
[0365] An adhesive tape was adhered to the surface of the
ink-receiving layer of the ink jet recording sheet, lightly pressed
by hand and then removed.
[0366] The test results were evaluated in the following four
classes.
[0367] 4: No change appeared in the ink-receiving layer.
[0368] 3: A very small portion of the ink-receiving layer was
removed, and the remaining ink-receiving layer is still usable for
practice.
[0369] 2: The ink-receiving layer was partially removed.
[0370] 1: Almost all of the ink-receiving layer was removed.
[0371] [Coating Layer Smoothness]
[0372] The smoothness of the ink-receiving layer of the ink jet
recording sheet was observed by the naked eye and evaluated in the
following three classes.
[0373] 3; The surface of the ink-receiving layer was quite
smooth.
[0374] 2: The ink-receiving layer surface was lightly
roughened.
[0375] 1: The ink-receiving layer surface was certainly roughened,
and had a bad appearance.
[0376] The test results are shown in Table 4.
5 TABLE 4 Ink-absorption Gloss of Coating layer Coating
Ink-absorbing Ink-absorption Water printed bonding layer Example
No. rate capacity resistance Color density ink images strength
smoothness Example IV-1 4 3 4 2.15 4 4 3 IV-2 4 4 4 2.13 4 3 3 IV-3
4 4 4 2.15 4 3 3 IV-4 4 4 4 2.16 4 4 3 IV-5 4 3 4 2.15 4 4 3 IV-6 4
3 4 1.75 4 4 3 IV-7 4 3 3 2.18 4 4 3 IV-8 4 3 4 2.17 4 4 3 IV-9 4 3
4 1.82 4 4 3 IV-10 4 3 4 1.84 4 4 3 IV-11 4 3 4 2.13 4 4 3 IV-12 4
4 4 2.14 3 3 3 IV-13 4 3 4 2.12 3 2 2 IV-14 4 3 4 2.16 3 2 2 IV-15
4 3 3 2.11 3 2 2 Comparative IV-1 1 1 1 2.31 1 2 2 Example IV-2 4 4
4 1.42 1 1 2
[0377] Table 4 clearly shows that the ink jet recording sheets of
Examples IV-1 to IV-15 in accordance with the present invention
were satisfactory in all of the tested results.
Example Group V
Examples V-1 to V-5 and Comparative Examples V-1 and V-3
[0378] In Example Group V, the following pigments were
employed.
[0379] (1) Silica colloidal particles A-5
[0380] An aqueous colloidal solution of silica colloidal particles
A-5 having a concentration of 8% by weight was prepared by
dispersing wet method synthetic amorphous silica particles having
an average primary particle size of 11 nm and an average secondary
particle size of 3 .mu.m and available under a trademark of Nipsil
HD-2 from Nihon Silica Kogyo K.K. in water, and pulverizing by
repeating a combination of a sand grinder treatment and an
ultrasonic homogenizer treatment until the average secondary
particle size of the pulverized silica particles reached 30 nm.
[0381] (2) Silica colloidal particles B-5
[0382] An aqueous colloidal solution of silica colloidal particles
B-5 having a concentration of 8% by weight was prepared by
dispersing wet method synthetic amorphous silica particles having
an average primary particle size of 16 nm and an average secondary
particle size of 9 .mu.m and available under a trademark of Nipsil
LP from Nihon Silica Kogyo K.K. in water and pulverizing by
repeating a combination of a sand grinder treatment and an
ultrasonic homogenizer treatment until the average secondary
particle size of the pulverized silica particles reached 50 nm.
Example V-1
[0383] An aqueous silica colloidal coating solution having a solid
content of 8% by weight was prepared from 100 parts by solid weight
of the silica colloidal dispersion A-5 and 40 parts by solid weight
of a polyvinyl alcohol (trademark: PVA-124, made by Kuraray Co.,
Ltd.) having a degree of polymerization of 2400 and a degree of
saponification of 98.5%, and coated on a surface of a transparent
polyethylene terephthalate (PET) film (trademark: Merinex D535,
made by ICI) having a thickness of 100 .mu.m and a haze value of
0.5% by using a Mayer bar and dried to form an ink-receiving layer
having a dry weight of 20 g/m.sup.2. An ink jet recording sheet was
obtained.
Example V-2
[0384] An aqueous silica colloidal coating solution having a solid
content of 12% by weight was prepared from 100 parts by solid
weight of the silica colloidal dispersion B-5 and 40 parts by solid
weight of a polyvinyl alcohol (trademark: PVA-124, made by Kuraray
Co., Ltd.) having a degree of polymerization of 2400 and a degree
of saponification of 98.5%, and coated on a surface of a
transparent polyethylene terephthalate (PET) film (trademark:
Merinex D535, made by ICI) having a thickness of 100 .mu.m and a
haze value of 0.5% by using a Mayer bar and dried to form an
ink-receiving layer having a dry weight of 20 g/m.sup.2. An ink jet
recording sheet was obtained.
Example V-3
[0385] An aqueous silica colloidal coating solution having a solid
content of 10% by weight was prepared from 100 parts by solid
weight of the silica colloidal dispersion A-5 and 40 parts by solid
weight of a polyvinyl alcohol (trademark: PVA-117, made by Kuraray
Co., Ltd.) having a degree of polymerization of 1800 and a degree
of saponification of 98.5%, and coated on a surface of a
transparent polyethylene terephthalate (PET) film (trademark:
Merinex D535, made by ICI) having a thickness of 100 .mu.m and a
haze value of 0.5% by using a Mayer bar and dried to form an
ink-receiving layer having a dry weight of 20 g/m.sup.2. An ink jet
recording sheet was obtained.
Example V-4
[0386] An aqueous silica colloidal coating solution having a solid
content of 8% by weight was prepared from 100 parts by solid weight
of the silica colloidal dispersion A-5 and 40 parts by solid weight
of a polyvinyl alcohol (trademark: PVA-235, made by Kuraray Co.,
Ltd.) having a degree of polymerization of 3500 and a degree of
saponification of 88.0%, and coated on a surface of a transparent
polyethylene terephthalate (PET) film (trademark: Merinex D535,
made by ICI) having a thickness of 100 tm and a haze value of 0.5%
by using a Mayer bar and dried to form an ink-receiving layer
having a dry weight of 20 g/m.sup.2. An ink jet recording sheet was
obtained.
Comparative Example V-1
[0387] An aqueous silica coating solution having a solid content of
15% by weight was prepared from 100 parts by solid weight of a wet
method synthetic amorphous silica (trademark: Nipsil HD-2, made by
Nihon Silicakogyo K.K.) having an average primary particle size of
11 nm and an average secondary particle size of 3 .mu.m and 40
parts by solid weight of a polyvinyl alcohol (trademark: PVA-124,
made by Kuraray Co., Ltd.) having a degree of polymerization of
2400 and a degree of saponification of 98.5%, and coated on a
surface of a transparent polyethylene terephthalate (PET) film
(trademark: Merinex D535, made by ICI) having a thickness of 100
.mu.m and a haze value of 0.5% by using a Mayer bar and dried to
form an ink-receiving layer having a dry weight of 20 g/m.sup.2. An
ink jet recording sheet was obtained.
Comparative Example V-2
[0388] An aqueous solution of 10% by solid weight of a polyvinyl
alcohol (trademark: PVA-117, made by Kuraray Co., Ltd.) having a
degree of polymerization of 1800 and a degree of saponification of
98.5% was coated on a surface of a transparent polyethylene
terephthalate (PET) film (trademark: Merinex D535, made by ICI)
having a thickness of 100 .mu.m and a haze value of 0.5% and dried
to form an ink-receiving layer having a dry weight of 20 g/m.sup.2.
An ink jet recording sheet was obtained.
Comparative Example V-3
[0389] An aqueous silica colloidal coating solution having a solid
content of 20% by weight was prepared from 100 parts by solid
weight of the silica colloidal dispersion A-5 and 80 parts by solid
weight of a styrene-butadiene copolymer latex (trademark: D693,
made by Nihon Goseigomu K.K.), and coated on a surface of a
transparent polyethylene terephthalate (PET) film (trademark:
Merinex D535, made by ICI) having a thickness of 100 .mu.m and a
haze value of 0.5% by using a Mayer bar and dried to form an
ink-receiving layer having a dry weight of 20 g/m.sup.2. An ink jet
recording sheet was obtained.
[0390] Tests
[0391] The ink jet recording sheets of Examples V-1 to V-4 and
Comparative Examples V-1 and V-3 were subjected to the following
tests.
[0392] The ink jet printing procedure was carried out by using a
practical ink jet printer (trademark: BJC-600J, made by Canon
Corp.).
[0393] [Haze Value (Transparency)]
[0394] The haze value was determined in accordance with JISK 7105
by using a haze value meter (model: HR-100) made by Murakami
Shikisaigijitsu Kenkyusho.
[0395] [Water Resistance]
[0396] A water drop was put on a surface of the ink-receiving layer
of the specimen, 30 minutes after the water drop-putting, the water
drop was wiped off, and the water-wetted portion of the
ink-receiving water was rubbed by a finger and the results were
observed by the naked eye and evaluated in the following three
classes.
[0397] 3: No change in the ink-receiving layer was found.
[0398] 2: The ink-receiving layer was partially removed.
[0399] 1: The ink receiving layer was completely removed.
[0400] [Ink Absorbing Rate (Ink Drying Rate)]
[0401] Each of black, yellow, magenta and cyan-colored inks was
solid printed on the ink-receiving layer of the specimen,
immediately every 5 seconds after the printing, a wood-free paper
sheet was superposed on the ink-printed portion of the specimen and
the transfer of the ink to the paper sheet was observed. The time
necessary to completely fix the printed ink in the ink receiving
layer and to cause the printed ink not to be transferred to the
paper sheet, was determined. The test results were evaluated in the
following four classes.
[0402] 4: The ink-fixing time was less than 5 seconds.
[0403] 3: The ink-fixing time was 5 seconds or more but less than
10 seconds.
[0404] 2: The ink-fixing time was 10 seconds or more but less than
50 seconds.
[0405] 1: The ink-fixing time was 50 seconds or more.
[0406] [Color density]
[0407] A solid printed specimen was placed on a coated paper sheet
and the color density of the solid ink images on the specimen was
measured by Macbeth reflection color density tester (model:
RD-920). The color density of the ink images was indicated by an
average value of five measurement results.
[0408] [OHP Projection]
[0409] Ink images formed on the specimen was projected onto an OHP,
and the sharpness of the projected images was observed by the naked
eye and evaluated in the following four classes.
[0410] 4: The background was light and the projected images were
very clear.
[0411] 3: The background was slightly dark and the projected images
were clear and practically satisfactory.
[0412] 2: The background was certainly dark and the clarity of the
projected images was unsatisfactory.
[0413] 1: The background was quite dark and the projected, images
were unclear.
[0414] The test results are shown in Table 5.
6TABLE 5 Haze Ink value Water absorbing Color OHP Example No. (%)
resistance rate density projection Example V-1 8 3 4 2.2 4 V-2 16 3
4 2.1 3 V-3 8 2 4 2.2 4 V-4 8 2 4 2.2 4 Comparative V-1 85 2 4 1.3
1 Example V-2 1 1 1 2.3 4 V-3 12 3 1 1.8 3
[0415] Table 5 shows that the ink jet recording sheets of Examples
V-1 to V-4 in accordance with the present invention had a high
transparency, a satisfactory water resistance, a satisfactory
ink-absorption property, and a high color density of ink images and
was usable for over head projection (OHP).
* * * * *