BACKGROUND OF THE INVENTION
Field of the Invention
[0001] The present invention relates to a method for antimicrobially treating printed matter.
Prior Art
[0002] Printed matter such as a notebook cover is repeatedly touched with hands and might
be contaminated by bacterium such as Escherichia coli, etc., which is sanitarily unfavorable.
It is desirable to conduct an antimicrobial treatment to keep the printed matter clean.
When such a treatment is applied to paper products, an antimicrobial agent is generally
impregnated in the paper. In a case of printed paper, however, it has been a problem
that an antimicrobial effect is insufficient because a surface of the paper is covered
by a printing ink.
[0003] Accordingly, it is an aim of the present invention to provide a novel method for
antimicrobially treating printed matter which can exhibit a sufficient antimicrobial
effect and thus keep it clean.
SUMMARY OF THE INVENTION
[0004] According to the present invention, there is provided a method for antimicrobially
treating printed matter in which a layer of an antimicrobial agent is formed on an
outermost surface of paper material.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] Fig. 1 is a cross-sectional view of printed matter used in Example 1.
[0006] Fig. 2 is a cross-sectional view of printed matter used in Example 4.
[0007] Fig. 3 is a cross-sectional view of printed matter used in Example 5.
DETAILED DESCRIPTION AND THE PREFERRED EMBODIMENTS
[0008] The antimicrobial layer on the outermost surface of the paper material may be formed
either by coating a paint containing a powdered antimicrobial agent therein or an
aqueous solution or an aqueous suspension of the antimicrobial agent on the paper
after printing of the paper is conventionally conducted in advance, or by printing
the surface of the paper with a printing ink containing the powdered antimicrobial
agent therein.
[0009] Materials to which the present invention is applicable include any repeatedly usable
printed matter made of paper, cloth, plastics, glass and the like.
[0010] Using an antimicrobial metal such as silver or an organic compound e.g. a benzalkonium
compound such as the chloride, a cetylpyridinium compound such as the chloride etc.,
a sparingly soluble phosphate may be intercalated or ion-exchanged to form an antimicrobial
agent.
[0011] Preferably, about 2.5 to 5 parts by weight of the antimicrobial agent is added to
100 parts by weight of a paint, water or a printing ink. Further, it is more preferable
to add thereto 5 to 10 parts by weight of wood vinegar liquid.
[0012] Although paints used herein include OP varnish (offset printing varnish), aquapack
varnish, UV-OP varnish and the like, any kind of paints generally used for coating
in the printing industry may be employed.
[0013] Coating is conducted by offset printing, offset rotary printing, photogravure printing
and the like, which may be employed depending on material to be printed. It is also
possible to coat using a suitable coater instead of printing.
[0014] According to the method of the present invention, a layer of the antimicrobial agent
is formed on the outermost surface of the printed matter, which effectively affects
bacterium absorbed on the printed surface.
[0015] The present invention will be described in detail in the following examples. However,
these examples are intended to illustrate the invention and are not to be constructed
to limit the scope of the invention.
Example 1
[0016] Using a printing ink of the following composition, a design 2 was printed on a surface
of cardboard 1 used as a notebook cover.
pigment |
23 (wt %) |
synthetic resin |
29 |
drying oil |
25 |
petroleum solvent |
18 |
film reinforcing agent |
2 |
set-off preventing agent |
1 |
drying agent and other solvent |
2 |
[0017] Then, a mixture of 3.5 parts by weight of a powdered antimicrobial agent prepared
by intercalating (ion-exchanging) a sparingly soluble phosphate with silver and 100
parts by weight of OP varnish having the following composition was coated by offset
printing thoroughly on the printed layer thus obtained so as to form an antimicrobial
layer 3.
synthetic resin |
35 (wt %) |
drying oil |
28 |
high-boiling petroleum solvent |
28 |
wax |
9 |
[0018] The notebook cover thus treated showed the same appearance and suitability as a conventional
one which had no antimicrobial layer.
[0019] The thus treated notebook cover and a conventional one, each having a size of 30
cm x 30 cm, were passed out to a hundred kindergarteners after their daily lesson
who were allowed to rub one palm on the treated cover according to the present invention
and the other palm on the conventionally printed cover. It was considered that a nearly
equal amount of bacterium was absorbed on these two kinds of covers. These covers
were kept two days and nights under conditions of humidity of 60 % and temperature
of 25 °C. As a result, it was observed that an amount of bacterium absorbed on the
conventional cover was seven times compared with the cover treated according to the
present invention.
Example 2
[0020] Using an aquapack varnish of the following composition instead of the OP varnish,
Example was repeated to prepare a printed notebook cover.
synthetic resin |
40 (wt %) |
isopropyl alcohol |
4 |
ethyl alcohol |
4 |
ammonia |
1 |
water |
51 |
[0021] The notebook cover treated according to the present invention exhibited the same
effect as what was obtained in Example 1.
Example 3
[0022] Using UV-OP varnish of the following composition instead of the OP vanish, Example
1 was repeated to prepare a printed notebook cover.
acrylic oligomer |
40 (wt %) |
acrylic monomer |
40 |
photo-initiator |
10 |
synthetic wax |
10 |
[0023] The notebook cover treated according to the present invention exhibited the same
effect as what was obtained in Example 1.
Example 4
[0024] A design 5 was printed on cardboard 4 used as a notebook cover similarly to Example
1. An aqueous suspension containing 100 parts of water and 3 parts by weight of the
same antimicrobial agent used in Example 1 was thoroughly coated on the printed surface
thus obtained by means of a roll coater so as to form an antimicrobial layer 6.
[0025] Similarly to Example 1, the notebook cover thus treated showed the same appearance
and suitability as a conventional one which had no antimicrobial layer.
[0026] An antimicrobial test was repeated similarly to Example 1 and yielded nearly the
same result.
Example 5
[0027] Using a mixture of 100 parts by weight of the same printing ink and 3.5 parts by
weight of the same antimicrobial agent used in Example 1, a design 8 was printed on
the cardboard 7 which was also used in Example 1.
[0028] The notebook cover thus treated showed the same appearance and suitability as a conventional
one which had no antimicrobial layer.
[0029] An antimicrobial test was repeated similarly to Example 1 and yielded nearly the
same result.
1. A method for antimicrobially treating printed matter, wherein a layer consisting of
or containing an antimicrobial agent is provided on an outermost surface of the printed
matter.
2. A method for antimicrobially treating printed matter as claimed in claim 1 in which
said layer is formed by coating a paint containing the powdered antimicrobial agent
on the printed matter after printing.
3. A method for antimicrobially treating printed matter as claimed in claim 1 in which
said layer is formed by coating a solution of the antimicrobial agent on the printed
matter after printing.
4. A method for antimicrobially treating printed matter as claimed in claim 1 in which
said layer is formed by coating a suspension of the antimicrobial agent on the printed
matter after printing.
5. A method for antimicrobially treating printed matter as claimed in claim 1 in which
said layer is formed by printing on a surface of material to be printed with a printing
ink containing the powdered antimicrobial agent.
6. A method for antimicrobially treating printed matter as claimed in any preceding claim
wherein the printed matter is of cardboard.
7. Antimicrobially-treated printed matter, wherein a layer consisting of or containing
an antimicrobial agent is provided on an outermost surface of the printed matter.