U.S. patent application number 11/431483 was filed with the patent office on 2006-11-16 for method of manufacturing a food container.
This patent application is currently assigned to Isamu SATO. Invention is credited to Shinkichi Hamano.
Application Number | 20060255042 11/431483 |
Document ID | / |
Family ID | 37388957 |
Filed Date | 2006-11-16 |
United States Patent
Application |
20060255042 |
Kind Code |
A1 |
Hamano; Shinkichi |
November 16, 2006 |
Method of manufacturing a food container
Abstract
A method of commercially manufacturing at low cost a
vegetable-fiber-material made food container of practical strength
includes the steps of: forming a board of a predetermined size from
pulp and at least one kind of vegetable fiber material other than
the pulp; coating the board with thermoplastic resin having a heat
sealing property; providing cuts at four corners of the board to
form sidewall pieces; and hot-pressing the board thus obtained
using a pair of press dies to form the food container, the pair of
dies being composed of female die and male die, wherein one of the
pairs of opposing sidewall pieces is arranged to be erected prior
to the other pair of opposing sidewall pieces and four corners are
bonded correspondingly to each other by a hot press process in
order to form the container.
Inventors: |
Hamano; Shinkichi; (Tokyo,
JP) |
Correspondence
Address: |
JORDAN AND HAMBURG LLP
122 EAST 42ND STREET
SUITE 4000
NEW YORK
NY
10168
US
|
Assignee: |
Isamu SATO
Tokyo
JP
|
Family ID: |
37388957 |
Appl. No.: |
11/431483 |
Filed: |
May 10, 2006 |
Current U.S.
Class: |
220/314 |
Current CPC
Class: |
B65D 5/28 20130101; B65D
5/2019 20130101; B65D 2565/385 20130101; B65D 1/34 20130101; B65D
5/2047 20130101 |
Class at
Publication: |
220/314 |
International
Class: |
B65D 45/28 20060101
B65D045/28 |
Foreign Application Data
Date |
Code |
Application Number |
May 10, 2005 |
JP |
2005-136957 |
Claims
1. Manufacturing method of food containers or covers thereof
comprising the steps of: forming a board of a predetermined size
from pulp and at least one kind of vegetable fiber material other
than the pulp; coating the board with thermoplastic resin having a
heat sealing property; providing cuts at four corners of the board
to form sidewall pieces; and hot-pressing the board thus obtained
using a pair of press dies to form food containers or covers of the
containers, a pair of dies being composed of female die and male
die; wherein one pair of the opposing sidewall pieces is arranged
to be erected prior to the other pair of opposing sidewall
pieces.
2. The manufacturing method as claimed in claim 1, wherein said
thermoplastic resin having the heat sealing property is applied to
one of surfaces of the board to provide coating thereon.
3. The manufacturing method as claimed in claim 1, wherein each of
the cuts is formed so that a top of an angled section or a cut line
reaches a corner of a bottom surface of the container to be
formed.
4. The manufacturing method as claimed in claim 3, wherein each of
the cuts is formed into V-shape at an angle between 20 and 60
degrees.
5. The manufacturing method as claimed in claim 3, wherein the cuts
are formed into funnel shapes or substantially Y-shapes.
6. The manufacturing method as claimed in claim 1, wherein one pair
of opposing sections of a concaved periphery of the female die is
provided with a pair of protruded portions, and one pair of
opposing sidewall pieces of the board placed on a pair of protruded
portions are formed so as to be erected prior to the other opposing
sidewall pieces.
7. The manufacturing method as claimed in claim 6, wherein the
opposing convex sections are away from the concave periphery of the
female die by at least a distance corresponding to a sword guard
shaped portion of the container to be formed.
8. The manufacturing method as claimed in claim 7, wherein guides
for holding side edges of the board is provided at the opposing
protruded portions or at adjacent positions thereto.
9. The manufacturing method as claimed in claim 8, wherein one of
the other opposing surfaces of the concave periphery of the female
die is provided with a guide to which one of the other side edges
of the board abuts.
10. The manufacturing method as claimed in claim 1, wherein one
pair of the opposing sidewall pieces is bent before performing the
pressing process, and arranged to be erected prior to the other
pair of the opposing sidewall pieces.
11. The manufacturing method as claimed in claim 1, wherein the
pulp and at least one kind of the vegetable fiber material other
than the pulp is a mixture of the pulp and the vegetable fiber
material other than the pulp.
12. The manufacturing method as claimed in claim 11, wherein the
vegetable fiber material other than the pulp is reed, sugar corn,
or kanaf.
13. The manufacturing method as claimed in claim 12, wherein a rate
of the pulp and the vegetable fiber material other than the pulp is
defined such that the vegetable fiber material other than the pulp
is between 20 and 80 wt % with respect to an entire mass of the
board.
14. The manufacturing method as claimed in claim 1, wherein the
thermoplastic resin having the heat sealing property is
polyethylene or polypropylene.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a method of manufacturing a
food container formed of vegetable fiber material, more
specifically, to a method of manufacturing the food container
formed of the vegetable fiber material commercially at low
cost.
[0003] 2. Related Background of the Invention
[0004] Conventional food containers for containing food, such as
lunch boxes or trays, are made of plastic materials like foamed
polyeurethane and so on. However, since the plastic materials have
a problem in disposing them after use, vegetable-fiber-made food
containers are strongly required in view of the environment
conservation.
[0005] However, there has been a problem in manufacturing the
vegetable-fiber-made food containers by die molding process that
only shallow containers with insufficient strength could be
manufactured. Further, in the case of the containers made from pulp
board, there has been a problem of costly manufacturing, since the
containers are so manufactured that cuts are formed at four
corners, sidewall pieces are erected, edges of the sidewall pieces
are brought into superposition to each other to apply bonding
agent, and the bonded portions are manually fixed. As a consequence
thereof, the vegetable-fiber-made food containers are not widely
diffused comparing to the other food containers, e.g., cheap trays
as presently sold in supermarkets.
[0006] Meanwhile, with regard to paper as vegetable-fiber-made
material, the natural forest including the virgin forest is to be
deforested for raw material of paper. However, it is a current
issue to deforest the natural or virgin forest not only from view
point of natural ecosystem where various animals inhabit but also
from local environmental disruption view point.
SUMMARY OF THE INVENTION
[0007] An object of the present invention is to provide a method of
manufacturing a vegetable-fiber-material made food container which
has a practical strength and can be manufactured commercially at
low cost.
[0008] Another object of the present invention is to provide a
method, considering a problem as to a global environment, of
manufacturing the vegetable-filer-material made food container at
low cost, capable of reducing an amount of pulp to be used
therefor.
[0009] The above stated objects can be achieved with the present
invention by employing the steps of: forming a board having a
predetermined size of pulp and at least one kind of the vegetable
fiber material other than the pulp; coating thermoplastic resin
having heat sealing property onto the board; providing cuts for
forming sidewall pieces at four corners of the board; and forming
the food container with thus obtained board subjected to a hot
press process with a pair of press dies, male and female dies, in
which a pair of the sidewall pieces opposing to each other are
arranged to be erected prior to another pair of the sidewall pieces
opposing to each other.
[0010] It is specifically preferable to apply the thermoplastic
resin having the heat sealing property onto one of the surfaces
(either one of a front or rear surface) of the board for the
purpose of coating, since it can be cost effectively substituted
for plastic material and is printable thereon. Practically, if the
coating is provided on both sides of the board, it becomes more
expensive than using the plastic material in the current technique,
which does not allow substitution for plastic material.
[0011] It is preferable for each of the cuts to be formed in such a
fashion that a top angle section or a cut line reaches a corner of
a bottom surface of the container to be formed. It is more
preferable for each of the cuts to be formed into V-shape at an
angle between 20 degrees and 60 degrees.
[0012] It is further preferable for each of the cuts to be formed
into a funnel shape or a substantially Y-shape since a water
leakage from inside a corner can be prevented effectively.
Especially, when the container contains something which may cause
the water leakage, the above stated configuration is effective.
[0013] Such an arrangement that a protruded portion is formed at
one of the opposing sections of an opening periphery of the female
die so that the pair of opposing sidewall pieces placed on the
protruded portion is erected earlier than the other pair of the
opposing sidewall pieces can make it possible to manufacture food
containers at commercially low cost, four corners of containers
being attached together through the hot press process using
dies.
[0014] In a case of manufacturing the container with a sword guard
shaped section, the opposing protruded portions are configured so
as to be away from the concaved periphery of the female die at
least by a distance corresponding to the sword guard shaped section
of the container to be formed.
[0015] Providing guides for holding side edges of the board on the
opposing protruded portion or at an adjacent position thereof
facilitates positioning of the board for forming the container.
Providing a guide abutting one of the other side edges of the board
at the other opposing side edges of the board of the concave
periphery of the female die further facilitates positioning of the
board.
[0016] Before the pressing process, if one pair of the opposing
sidewall pieces, which are arranged to be erected prior to the
other pair of the opposing sidewall pieces, is bent, conventional
dies can be employed to manufacture the container. However, when
considering the productivity of the container, the above stated
arrangement will be more preferable to produce the container.
[0017] It is preferable that the pulp and at least one kind of the
vegetable fiber material other than the pulp are made of mixture of
the pulp and the vegetable fiber material other than the pulp in
view of the protection of the global environment destruction due to
deforestation.
[0018] It is preferable that the vegetable fiber material other
than the pulp be made of reed, sugar cone or kanaf.
[0019] It is preferable that a rate of the pulp and the vegetable
fiber material other than the pulp be adjusted so that the
vegetable fiber material other than the pulp is between 20 and 80
wt % with respect to the pulp. The less degrees, the less effect to
the protection of the global environment, and the more degrees, the
less strength and the less adhesive ability of an adhering
section.
[0020] It is preferable to employ polyethylene or polypropylene as
the thermoplastic resin having the heat sealing property according
to the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a plan view illustrating a state of a food
container according to the present invention before pressing
process.
[0022] FIG. 2 is a plan view illustrating a state of another food
container according to the present invention before pressing
process.
[0023] FIG. 3 is a plan view illustrating a state of another food
container according to the present invention before pressing
process.
[0024] FIG. 4 is a plan view illustrating a state of another food
container according to the present invention before pressing
process.
[0025] FIG. 5 is a perspective view illustrating an example of the
food container manufactured by a method according to the present
invention.
[0026] FIG. 6 is a perspective view illustrating an example of a
female die to be used in the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0027] Next an embodiment of the present invention is
described.
[0028] The present invention is composed of the following
processes.
[0029] (1) The board of the predetermined size is formed of the
pulp and at least one kind of the vegetable fiber material other
than the pulp.
[0030] (2) Thermoplastic resin having the heat sealing property is
applied to the board.
[0031] (3) Cuts are formed at four corners of the board in order to
form sidewall pieces.
[0032] (4) Thus obtained board is subjected to the hot press
process using a pair of press dies, male and female in order to
form the food container.
[0033] The process (1) can be performed by a known method of
manufacturing the board from pulp. More specifically, the board is
obtainable through the processes that pulp suspended in water is
subjected to a sheet-forming process, followed by a water-squeezing
process and drying process. The board obtained in the above
processes is cut, if required, into a square shape of the
predetermined size, and, preferably, into the square shape having
R-shapes at four corners thereof as shown in FIGS. 1 to 4. It is
preferable that the board contain water proof agent. Further, in
the case of containing food which weeps oil, it is preferable for
the board to contain oil proof agent in addition to the water proof
agent.
[0034] As the vegetable-fiber-made material other than the pulp
used in the present invention, it is preferable to use reed, sugar
cone or kanaf. More specifically, using the reed is preferred since
it is excellent in strength of the resultant container.
[0035] In the present invention, it is preferable to use a mixture
of the pulp and the vegetable fiber material other than the pulp in
view of the protection of the global environment due to the
deforestation.
[0036] As to the rate of the pulp and the vegetable fiber material
other than the pulp, it is preferable that the vegetable fiber
material other than the pulp be between 20 and 80 wt %, more
preferably between 30 and 60 wt %. The less addition of the
vegetable fiber material, the less effect in protection of the
global environment, while the more addition of the vegetable fiber
material, the less strength and the more tendency of abruption of
the bonding section.
[0037] The process (2) in which the thermoplastic resin having the
heat sealing property is applied to the board in a coating manner
may be done after a formation of the cuts or may be done before the
formation of the cuts; however, the coating process is done before
the formation of the cuts in the present embodiment. The
thermoplastic resin is preferably applied to either surface, front
or rear, of the board. If the thermoplastic resin is applied to
both surfaces, diffusion of the container according to the present
invention will be adversely effected for the reason of an
expensiveness of the container at present and further no printable
surface is obtained. In addition, the thermoplastic resin is
preferred to be applied to the surface on which the food is placed.
The reason for applying coating on the surface on which the food is
placed is that the coating prevents juice or the like from
infiltrating into the container. As the thermoplastic resin, it is
preferable to use especially polyethylene or polypropylene.
[0038] A content of the thermoplastic resin differs depending on
the kinds of the thermoplastic resin. Here, a range between 2 and
10% with respect to a mass of the board, more preferably, between 3
and 6% with respect to the mass of the board. Here, the "content"
is represented by a percentage of the "mass of the heat sealing
agent to be applied to the board" with respect to the entire mass
of the board of which one surface is applied with the thermoplastic
resin.
[0039] The cuts formed in the process (3) may be just formed into
cut lines; however, it is preferable for the cuts to be formed into
V-shapes at an angle equal to or less than 90 degrees or, more
preferably, between 20 degrees and 60 degrees as shown in FIG.
1.
[0040] FIG. 1 illustrates an example of forming the cuts 1 in
accordance with the process (3) in which the board formed into a
square shape (rectangular shape) with round corners at four corners
is provided with cuts 1 having V-shapes and a state is shown that
long sidewall pieces 3, 3' and short sidewall pieces 4, 4' are
provided consecutively on the bottom surface 2. Note that,
reference numeral 5 in FIG. 1 represents concave portions formed
continuously between the bottom surface 2 and the sidewall pieces
3, 3' and 4, 4', which are formed by the pressing process using
dies in order to increase the strength of trays to be manufactured,
which however is not yet formed in this stage. In this stage, the
board is actually as shown in FIG. 4.
[0041] FIG. 2 illustrates another example of forming the cuts in
accordance with the process (3), in which cuts 1a are so formed
that the V-shaped notches 1' are consecutively provided with the
prolonged cut lines 6 to finally reach the corners of the bottom
surfaces 2, resulting in having an appearance of substantially
y-shapes (a small letter of y). With such a configuration, areas
overlapping each other at both ends of the sidewall pieces 3, 3'
and 4, 4' adjacent to the bottom surface 2 can be large; therefore
the water leakage from the corners can be avoided effectively.
[0042] FIG. 3 illustrates another example of forming the cuts in
accordance with the process (3), in which V-shaped notches 1'' of
small angles are consecutively provided from upper bases (bottom
ends) of the tranpezoidal notches 7 to the corners of the bottom
surface 2 in order to finally form funnel shaped or substantially
Y-shaped cuts 1b. With such a configuration, areas overlapping each
other at both ends of the sidewall pieces 3, 3' and 4, 4' adjacent
to the bottom surface 2 can be large, therefore the water leakage
from the corners can be avoided effectively.
[0043] FIG. 4 illustrates another example of forming the cuts in
accordance with the process (3), in which cuts 1c are so formed
that the cut lines 6' are consecutively provided from the notches
1'' of round V-shape to the corners of the bottom surface 2, in
order to finally form substantially Y-shapes (a large letter of Y).
In the embodiment as shown in FIG. 2, the cut line 6 extends from
one of the lines of the V-shaped cuts; however, in the embodiment
as shown in FIG. 4, the cut line 6' is a bisector of the angle of
the V-shaped cut.
[0044] In the embodiment as illustrated in FIG. 2, the cut line 6
may be provided with a small clearance. In the embodiment as
illustrated in FIG. 3, each of the V-shaped notches 1'' may be a
cut line. Further, regarding the expressions in the present
specification as to V-shape, Y-shape and funnel shape, the shapes
are not necessarily defined precisely in such shapes but may be
substantially such shapes. In short, the shapes of the notches
should not be strictly defined as far as the top angle portions or
the cut lines of the notches reach corners of the bottom surface
2.
[0045] In order to form the food container by means of a pair of
hot press dies consisted of the male die and the female die in
accordance with the process (4), one of the pairs of the opposing
sidewall pieces of the board on which cuts are formed as
illustrated in FIGS. 1 to 4 is erected prior to the other pair of
the opposing sidewall pieces and the board thus formed is placed in
the female die to be subjected to a hot pressing process by the
upper male die in order to form the container, and simultaneously,
the board is subjected to the heat sealing process in order to bond
the sidewall pieces at the four corners correspondingly each other.
Then, as shown in FIG. 5, the container 8 is so formed that corner
sections 13 at the four corners have round shapes.
[0046] Either pair of the opposing sidewall pieces may be erected
prior to the other pair; however, it is preferable for the pair of
short sidewall pieces 4, 4' to be erected prior to the other pair
since it is easier. If the sidewall pieces are preliminary erected
by means of a paper folding machine, a conventional press dies can
also be utilized to form the container.
[0047] FIG. 6 illustrates an example of a female die (concave die)
9 to be used in manufacturing according to the present invention,
in which opposing sections at short side surfaces of the upper
periphery of the concave section 10 of the female die 9 are
provided with rods 11, 11' having square shapes in cross section in
a manner opposing to each other and slightly spaced from the
concave section 10. On the rods 11, 11', guiding boards 12, 12' are
provided to stand thereon. At a backside of the concave section 10
of the female die 9, a guiding board 12'' is provided to stand
thereon.
[0048] The board illustrated in FIG. 4 is placed so that the pair
of short sidewall pieces 4, 4' is held between the guiding plates
12, 12' and one of the long sidewall pieces 3 (or 3') is abutted on
a guide plate 12'' via the rods 11, 11' on the concave section 10
of the female die 9. Then, the male die (convex die which is not
shown in FIG. 6) is descended and brought into fit with the concave
section 10 of the female die 9 from the above to be subjected to
the hot pressing process.
[0049] Accordingly, the pair of the opposing sidewall pieces 4, 4'
is erected prior to the other pair of the opposing sidewall pieces
3, 3', and then the container as shown in FIG. 5 can be
manufactured in a single step by a complete fitting and the hot
pressing process. Note that, as shown in FIG. 5, the sword guard
shaped section 14 provided at an upper edge and the concave
sections 5 of the container are formed by the hot pressing process
using the male and female dies.
[0050] In order to form the sword guard shaped section 14 on the
upper edge of the container, as shown in FIG. 6, the rods 11, 11'
are away from the both side ends of the concave section by the
distance corresponding to the sword guard shaped section. The
concave section 10 may include steps formed thereon, and the male
die is formed into a shape including the steps so as to fit into
the concave section. The sword guard shaped section may be
obviously formed utilizing the steps at which the female die and
the male die are closely contacted with each other.
[0051] A cover can be consecutively formed with the container of
the present invention. In the case of forming the consecutive
cover, the cover may be formed consecutively with the sidewall
piece (preferably with either one of the sidewall pieces 3, 3') as
shown in FIGS. 1 to 4.
[0052] As shown in FIG. 5, corner sections 13 at four corners are
thick because portions of the board are superimposed each other,
consequently portions of the female die and/or the male die at
which the corner sections are formed are preferred to be thinned by
that amount.
[0053] The food containers manufactured by the method according to
the present invention are not limited to, but are suitable for the
use of lunch boxes, fermented soybeans containers, trays, covers of
the lunch boxes, and the like.
[0054] According to the present invention, the food container
formed of the vegetable-fiber-made material and having practical
strength can be produced commercially at low cost, therefore the
container according to the present invention is sufficient enough
as an alternative to the food container made of plastic, resulting
in remarkably contributing to the environment protection.
[0055] Further, according to the present invention, a food
container, being formed of vegetable fiber material which is cheap
and uses reduced amount of pulp, can be obtained, thereby
contributing to protection of the global environment destruction
due to deforestation.
* * * * *