U.S. patent application number 11/909417 was filed with the patent office on 2009-09-24 for finely cut paper product for use in mixing with resin, ecologically sound resin composition comprising the same, and ecologically sound molded resin article using the composition.
This patent application is currently assigned to HOKUETSU PAPER MILLS, LTD.. Invention is credited to Yasuji Kazumori, Katsumi Onozuka.
Application Number | 20090236063 11/909417 |
Document ID | / |
Family ID | 37023487 |
Filed Date | 2009-09-24 |
United States Patent
Application |
20090236063 |
Kind Code |
A1 |
Onozuka; Katsumi ; et
al. |
September 24, 2009 |
FINELY CUT PAPER PRODUCT FOR USE IN MIXING WITH RESIN, ECOLOGICALLY
SOUND RESIN COMPOSITION COMPRISING THE SAME, AND ECOLOGICALLY SOUND
MOLDED RESIN ARTICLE USING THE COMPOSITION
Abstract
An object of the invention is to provide a finely cut paper
product exhibiting a good workability in the production of a
paper-resin composition comprising a mixture of a resin and a
natural fiber, and improve the fluidity of an ecologically sound
paper-resin composition using the finely cut paper product, so as
to improve the moldability thereof when the composition is
subjected to a working such as injection molding. An other object
thereof is to restrain the generation of yellowing or the
generation of an odor. The finely cut paper product for use in
mixing with resin according to the invention is obtained by
pulverizing neutral or alkaline pigment-free coated paper which
comprises 70 to 100% by mass of hardwood bleached chemical pulp, 0
to 20% by mass of softwood bleached chemical pulp and 0 to 20% by
mass of an inorganic filler, and has an ISO brightness of 70% or
more. The ecologically sound paper-resin composition comprising it
comprises 50% or more by mass of the above-mentioned finely cut
paper product for use in mixing with resin, wherein the balance is
made mainly of a synthetic resin, or wherein the main component is
made of the above-mentioned finely cut paper product for use in
mixing with resin and a biodegradable resin.
Inventors: |
Onozuka; Katsumi; (Niigata,
JP) ; Kazumori; Yasuji; (Niigata, JP) |
Correspondence
Address: |
DARBY & DARBY P.C.
P.O. BOX 770, Church Street Station
New York
NY
10008-0770
US
|
Assignee: |
HOKUETSU PAPER MILLS, LTD.
Niigata
JP
|
Family ID: |
37023487 |
Appl. No.: |
11/909417 |
Filed: |
September 2, 2005 |
PCT Filed: |
September 2, 2005 |
PCT NO: |
PCT/JP2005/016129 |
371 Date: |
September 21, 2007 |
Current U.S.
Class: |
162/141 |
Current CPC
Class: |
C08L 23/10 20130101;
C08L 51/06 20130101; D21H 17/62 20130101; C08L 1/02 20130101; C08L
101/16 20130101; C08L 67/04 20130101; C08L 97/00 20130101; C08L
93/04 20130101; C08L 23/12 20130101; C08L 1/02 20130101; C08L
2666/02 20130101; C08L 23/10 20130101; C08L 2666/24 20130101; C08L
67/04 20130101; C08L 2666/26 20130101; C08L 93/04 20130101; C08L
2666/02 20130101; C08L 101/16 20130101; C08L 2666/26 20130101 |
Class at
Publication: |
162/141 |
International
Class: |
D21H 11/02 20060101
D21H011/02 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 23, 2005 |
JP |
2005-083994 |
Claims
1-7. (canceled)
8. A finely cut paper product for use in mixing with resin,
comprising being obtained by pulverizing neutral or alkaline
pigment-free coated paper which comprises 70 to 100% by mass of
hardwood bleached chemical pulp, 0 to 20% by mass of softwood
bleached chemical pulp and 0 to 20% by mass of an inorganic filler,
and has an ISO brightness of 70% or more.
9. The finely cut paper product for use in mixing with resin
according to claim 8, comprising one or more selected from calcium
carbonate and talc as the inorganic filler.
10. The finely cut paper product for use in mixing with resin
according to claim 8, comprising one or more selected from calcium
carbonate and talc as the inorganic filler and having an apparent
bulk specific gravity of 0.1 or more.
11. An ecologically sound paper-resin composition, comprising 50%
or more by mass of the finely cut paper product for use in mixing
with resin according to claim 8, wherein the balance is made mainly
of a synthetic resin.
12. The ecologically sound paper-resin composition according to
claim 11, wherein the finely cut paper product for use in mixing
with resin comprises one or more selected from calcium carbonate
and talc as the inorganic filler.
13. The ecologically sound paper-resin composition according to
claim 11, wherein the finely cut paper product for use in mixing
with resin comprises one or more selected from calcium carbonate
and talc as the inorganic filler and has an apparent bulk specific
gravity of 0.1 or more.
14. An ecologically sound paper-resin composition, wherein being
made mainly of the finely cut paper product for use in mixing with
resin according to claim 8 and a biodegradable resin.
15. The ecologically sound paper-resin composition according to
claim 14, wherein the finely cut paper product for use in mixing
with resin comprises one or more selected from calcium carbonate
and talc as the inorganic filler.
16. The ecologically sound paper-resin composition according to
claim 14, wherein the finely cut paper product for use in mixing
with resin comprises one or more selected from calcium carbonate
and talc as the inorganic filler and has an apparent bulk specific
gravity of 0.1 or more.
17. The ecologically sound paper-resin composition according to
claim 14, wherein comprising a rosin-based resin.
18. The ecologically sound paper-resin composition according to
claim 15, wherein comprising a rosin-based resin.
19. The ecologically sound paper-resin composition according to
claim 16, wherein comprising a rosin-based resin.
20. An ecologically sound molded article, wherein being molded by
use of the ecologically sound paper-resin composition according to
claim 11.
21. The ecologically sound molded article according to claim 20,
wherein the finely cut paper product for use in mixing with resin
contained in the ecologically sound paper-resin composition
comprises one or more selected from calcium carbonate and talc as
the inorganic filler.
22. The ecologically sound molded article according to claim 20,
wherein the finely cut paper product for use in mixing with resin
contained in the ecologically sound paper-resin composition
comprises one or more selected from calcium carbonate and talc as
the inorganic filler and has an apparent bulk specific gravity of
0.1 or more.
23. An ecologically sound molded article, wherein being molded by
use of the ecologically sound paper-resin composition according to
claim 14.
24. The ecologically sound molded article according to claim 23,
wherein the finely cut paper product for use in mixing with resin
contained in the ecologically sound paper-resin composition
comprises one or more selected from calcium carbonate and talc as
the inorganic filler.
25. The ecologically sound molded article according to claim 23,
wherein the finely cut paper product for use in mixing with resin
contained in the ecologically sound paper-resin composition
comprises one or more selected from calcium carbonate and talc as
the inorganic filler and has an apparent bulk specific gravity of
0.1 or more.
26. The ecologically sound molded article according to claim 23,
wherein the ecologically sound paper-resin composition comprises a
rosin-based resin.
27. The ecologically sound molded article according to claim 24,
wherein the ecologically sound paper-resin composition comprises a
rosin-based resin.
28. The ecologically sound molded article according to claim 25,
wherein the ecologically sound paper-resin composition comprises a
rosin-based resin.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a U.S. national phase application under 35 U.S.C.
.sctn.371 of International Patent Application No.
PCT/JP2005/016129, filed Sep. 2, 2005 and claims the benefit of
Japanese Application No. 2005-083994, filed Mar. 23, 2005. The
International Application was published in Japanese on Sep. 28,
2006 as International Publication No. WO 2006/100793 under PCT
Article 21(2). The contents of the above applications are
incorporated herein in their entirety.
TECHNICAL FIELD
[0002] The present invention relates to a finely cut paper product
suitable when a paper-resin composition comprising a mixture of a
resin and a natural fiber is produced, and an ecologically sound
paper-resin composition using the finely cut paper product. More
specifically, this finely cut paper product is a product having an
improved workability when the product is compounded into a resin.
The paper-resin composition, into which the finely cut paper
product is incorporated, is of an ecologically sound type, and
further has quality equivalent to that of conventional resin
compositions. The invention also relates to a paper-resin
composition which is used to give a molded product which less
yellows and causes the generation of an odor to be decreased.
BACKGROUND ART
[0003] Conventionally, resin compositions comprising various
synthetic resins, and various molded products made by use thereof
have been produced and used in many amounts. About molded products
each using some resin, such as polyester resin, the collection,
regeneration, and reuse thereof have been advancing. However, under
the present circumstances, many resin molded products are
incinerated or disposed of as in combustibles. In the case that the
resin compositions are incinerated, there are caused problems that
incinerators are damaged since high calories are generated when the
compositions are incinerated, and other problems.
[0004] As manners for solving the problems, attention is paid to a
composition into which not only a synthetic resin but also wood
flour or a finely cut paper product as a filler are incorporated
(see, for example, Japanese Patent Application Laid-open (JP-A) No.
2001-270508) and use of a biodegradable resin, which can be
naturally degraded, instead of any synthetic resin (see, for
example, JP-A No. 2002-272573) under a situation that high cares
are taken of the environmental. These manners have been partially
put into practical use.
[0005] Compositions comprising a natural fiber and a resin are
known, and various suggestions are made. However, there are not a
very large number of examples wherein about the structure of a
natural fiber material to be used, in particular, that of a paper
or pulp pulverized product is specified. As a technique wherein a
fiber material for being blended with resin is specified, use of a
pulverized product of paper or pulp wherein the amount of
chlorine-containing materials is made as small as possible is
suggested (see, for example, JP-A No. 2003-73988).
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0006] However, the most serious problem at the time of using a
paper or pulp pulverized product as a fiber material for being
blended with resin is that the pulverized product becomes very
bulky with ease. When the bulky pulverized product is mixed with
and kneaded into a resin having a relatively high bulk specific
gravity, the pulverized product damages work efficiency and
production efficiency remarkably. Thus, a pulverized product having
a higher bulk specific gravity is desired.
[0007] About compositions wherein a resin is blended with a finely
cut paper product, the fluidity thereof becomes lower as the
proportion of the finely cut paper product becomes higher. It
becomes therefore difficult that the blend of 50% or more by mass
thereof, by which the resultant will belong to the category of
paper, is attained. For this reason, finely cut paper products
having a good fluidity are desired.
[0008] However, suggestions are hardly known about technical means
making it possible to attain these two subjects at the same
time.
[0009] Moreover, a problem of the composition made of a synthetic
resin and wood flour is that when high temperature heat is applied
thereto, the wood flour gets discolored so that a white composition
is not easily produced.
[0010] In the case that paper is used instead of wood flour,
discoloration can be considerably restrained when the paper is
woodfree paper, wherein bleached chemical pulp is used. Thus, a
white paper-resin composition can be obtained. In the case that
brightness is further required, titanium oxide or calcium carbonate
is usually blended therewith. According to these countermeasures,
yellowing in the appearance can be decreased to such an extent that
attention is hardly paid to the yellowing; however, it was found
out that when water splashes the paper-resin composition or the
molded product, there is generated a phenomenon that the region
that the water splashes yellows locally. The mechanism thereof is
not necessarily evident. The inventors have examined the mechanism.
As a result, it has been proved that the phenomenon is caused by a
matter that a water-soluble colored component in the paper-resin
composition is extracted into a layer of water adhering on the
surface thereof, and this component originates from the paper in
used. When such a phenomenon is caused, the quality and the
appearance of the molded product are remarkably damaged. Thus, it
is desired to develop a paper-resin composition which does not
yellow even if the composition is splashed by water or is immersed
into water. However, no literatures are found in which yellowing of
paper-resin compositions, in particular, a yellowing phenomenon in
which water is involved is positively taken up.
[0011] Dependently on the paper in used, not only yellowing but
also an odor may be generated. There is caused, in particular, a
problem that heat when the composition is molded causes the
generation of an odor and the odor remains in the molded product on
occasion. It has been desired to solve the problem.
[0012] Thus, a first object of the present invention is to provide
a finely cut paper product exhibiting a good workability in the
production of a paper-resin composition comprising a mixture of a
resin and a natural fiber, and improve the fluidity of an
ecologically sound paper-resin composition using the finely cut
paper product, so as to improve the moldability thereof when the
composition is subjected to a processing such as injection molding.
When this object is attained, the blending ratio of the finely cut
paper product can be made high.
[0013] A second object of the invention is to provide an
ecologically sound paper-resin composition that contains paper but
causes a remarkable decrease of yellowing based on heat in the step
of processing the composition, in particular, yellowing in which
water is involved, and that simultaneously restrains the generation
of an odor.
[0014] A third object of the invention is to provide an
ecologically sound molded product which-uses the above-mentioned
ecologically sound paper-resin composition, which contains paper
but less yellows, in particular, less yellows even when water
splashes the molded product, and which simultaneously less
generates an odor.
SUMMARY OF THE INVENTION
[0015] The inventors have made eager investigations about
relationship between the composition/form of paper used in a finely
cut paper product and the finely cut paper product, and
relationship between the composition/form and the workability when
the product is mixed with a resin or the quality of the paper-resin
composition obtained at this time. As a result, it has been found
out that the above-mentioned objects can be simultaneously attained
by selecting a paper species having a specified composition/form
from various paper species, so that the present invention has been
made. Accordingly, the finely cut paper product for use in mixing
with resin according to the present invention is a product obtained
by pulverizing neutral or alkaline pigment-free coated paper which
comprises 70 to 100% by mass of hardwood bleached chemical pulp, 0
to 20% by mass of softwood bleached chemical pulp and 0 to 20% by
mass of an inorganic filler, and has an ISO brightness of 70% or
more.
[0016] The finely cut paper product for use in mixing with resin
according to the invention preferably comprises one or more
selected from calcium carbonate and talc as the inorganic filler.
The product has a high brightness. Thus, a bad effect given onto
the lifespan of the blade of any pulverizer is small.
[0017] The finely cut paper product for use in mixing with resin
according to the invention preferably has an apparent bulk specific
gravity of 0.1 or more, so that the work efficiency for compounding
the product into a resin becomes good.
[0018] The ecologically sound paper-resin composition according to
the invention is a composition comprising 50% or more by mass of
the above-mentioned finely cut paper product for use in mixing with
resin, wherein the balance is made mainly of a synthetic resin. The
paper-resin composition referred to herein is a mixture wherein a
paper component and a resin component are mixed therewith by
kneading them.
[0019] The ecologically sound paper-resin composition according to
the invention is made mainly of the above-mentioned finely cut
paper product for use in mixing with resin and a biodegradable
resin.
[0020] The ecologically sound paper-resin composition according to
the invention preferably comprises a rosin-based resin. The
fluidity of the composition is improved, so that softness can be
given thereto.
[0021] The ecologically sound molded article according to the
invention is molded by use of the above-mentioned ecologically
sound paper-resin composition.
[0022] The finely cut paper product for use in mixing with resin of
the invention is good in workability in the production of a
paper-resin composition comprising a mixture of a resin and a
natural fiber. The ecologically sound paper-resin composition using
this finely cut paper product is good in fluidity, and is good in
moldability when the composition is subjected to a processing such
as injection molding. Moreover, the blending ratio of the finely
cut paper product in the ecologically sound paper-resin composition
can be made high. In the ecologically sound paper-resin composition
of the invention, which comprises the finely cut paper product for
use in mixing with resin, yellowing on the basis of heat in the
step of working the resin, in particular, yellowing in which water
is involved is remarkably less caused although the composition
contains paper. Simultaneously, the composition is restrained from
generating an odor. The ecologically sound molded product of the
invention, using the ecologically sound paper-resin composition,
contains paper; however, yellowing is less caused, in particular,
yellowing is less caused even when water splashes the molded
product. Simultaneously, an odor is less generated therefrom. As a
result, the product can be applied to the field of food.
DETAILED DESCRIPTION OF THE INVENTION
[0023] The present invention will be described in detail
hereinafter. However, the invention is not interpreted so as to be
limited to the description.
[0024] The finely cut paper product for use in mixing with resin
according to the invention is obtained by pulverizing neutral or
alkaline pigment-free coated paper which comprises 70 to 100% by
mass of hardwood bleached chemical pulp, 0 to 20% by mass of
softwood bleached chemical pulp, and 0 to 20% by mass of an
inorganic filler, and has an ISO brightness of 70% or more. In the
invention, the pigment-free coated paper is coated paper which does
not contain any pigment in its coated layer, or uncoated paper.
[0025] The paper used in the invention is any paper classified into
the so-called woodfree paper or waste paper thereof, or may be any
pulp sheet (hereinafter, these paper species will be collectively
called "paper"). The pulp which constitutes the paper used in the
invention needs to be bleached chemical pulp. The bleached chemical
pulp is not particularly limited in the kind thereof, and may be
bleached sulfite pulp or bleached kraft pulp, the by the name of
which is BSP or BKP, respectively. It is preferred to avoid using
unbleached chemical pulp. It is preferred to avoid using mechanical
pulp or semichemical pulp even if the pulp is bleached. It is also
preferred to avoid using waste paper from paper containing the
pulp, which is classified to wood containing paper. Known examples
of the mechanical pulp include GP, TMP, CTMP, and bleached pulps
thereof. In unbleached pulp, mechanical pulp, and semichemical
pulp, lignin remains in a remarkable amount; even when the
brightness of the finely cut paper product and the paper-resin
composition is high, lignin causes yellowing or an odor in
subsequent steps.
[0026] The fiber which constitutes bleached chemical pulp is very
important. It is more preferred that the fiber length is shorter.
Ordinarily-used fiber is hardwood fiber. The blending ratio of the
hardwood bleached chemical pulp used in the invention in the paper
is indispensably at least 70% or more by mass, more preferably 80%
or more by mass. The blending ratio is desirably higher. If the
ratio is less than 70% by mass, there are caused problems that the
bulk specific gravity increases and the strength of the mixture
with the resin lowers, and other problems although the effect of
the pulp is varied in accordance with the constituent material of
the balance. Softwood fiber, which generally has a longer fiber
length than hardwood fiber, is incorporated into paper in order to
give strength to the paper in many cases. However, it is more
preferred that the proportion of softwood fiber, that is, softwood
bleached chemical pulp in the invention is smaller. The blending
ratio thereof in the paper is at most 20% or less. If the ratio is
more than 20% by mass, the bulk specific gravity of the finely cut
paper product is small so that the kneading-workability into the
resin deteriorates. Thus, the fluidity of the resultant paper-resin
composition also lowers.
[0027] It is necessary that the blending ratio of the inorganic
filler in the paper is 20% or less by mass. If the ratio is more
than 20% by mass, the strength of the paper-resin composition
lowers and further a bad effect is given onto the lifespan of the
blade of any pulverizer. The kind of the used inorganic filler is
preferably at least one selected from calcium carbonate and talc
from the viewpoint of the brightness thereof and the lifespan of
the blade. The use of calcium carbonate is preferred since neutral
paper is obtained even if no pH-adjustment with a chemical is
performed. The kind of the calcium carbonate is more preferably
light calcium carbonate from the viewpoint of the wear
characteristics thereof. An advantage of the use of talc is that
talc is excellent in wear characteristics. These fillers may be
used alone or in a mixture form. The incorporation of an inorganic
filler other than these fillers causes no problem if the amount
thereof is small. It is however preferred to use a filler without
giving bad effect to wear characteristics of any pulverizer.
[0028] The paper in use is preferably paper comprising 70 to 100%
by mass of hardwood bleached chemical pulp, 0 to 20% by mass of
softwood bleached chemical pulp and 0 to 20% by mass of an
inorganic filler. The paper may contain additives such as a paper
strength additive, a sizing agent, a retention aid, and a drainage
aids to such an extent that the advantageous effects of the
invention are not hindered. The paper may be surface-treated with
various starches, a surface sizing agent, or the like by means of a
size press, a gate roll or some other device.
[0029] The brightness of the paper in used needs to be an ISO
brightness of 70% or more. If the brightness is lower than 70%,
yellowing based on water is caused. The ISO brightness is more
preferably 75% or more. As the brightness is higher, a more
preferred result is obtained. If the brightness of the paper in
used itself is low, it is impossible to avoid a problem of
yellowing based on water even if a manner for raising the
brightness, such as addition of a highly white filler, is performed
in a subsequent production of a paper-resin composition.
[0030] The paper in used is preferably neutral or alkaline
pigment-free coated paper. If the paper is acidic, at the time of
molding the paper-resin composition, a bad effect, such as
corrosion of the mold, may be produced onto the molding. If pigment
coated paper is used, synthetic binders, in particular, various
latexes used in its coated layer cause the generation of a bad odor
or a harmful gas when the paper is heated.
[0031] The apparent bulk specific gravity of the finely cut paper
product obtained by pulverizing the above-specified paper is
preferably 0.1 or more. When the above-mentioned paper is used, a
finely cut paper product having an apparent bulk specific gravity
of 0.1 can be obtained with relative ease by controlling conditions
for the pulverization. If the apparent bulk specific gravity is
less than 0.1, the workability may lower remarkably when the finely
cut paper product is compounded into a resin.
[0032] The finely cut paper product is kneaded into one or more out
of various resins, whereby the product is turned into a paper-resin
composition. When the proportion of the finely cut paper product is
set to 50% or more by mass, an ecologically sound paper-resin
composition is obtained. When a biodegradable resin is used as the
resin, an ecologically sound paper-resin composition is
obtained.
[0033] Examples of the synthetic resin used in the invention
include general-use resins such as polyethylene resin,
polypropylene resin, polystyrene resin,
acrylonitrile/butadiene/styrene resin, acrylonitrile/styrene resin,
urethane resin, polyester resin, polycarbonate resin, and modified
resins thereof. These synthetic resins may be newly-synthesized
products, or pulverized products or recycled products of used
molded products, and may each be a single product or a mixture.
[0034] Examples of the biodegradable resin used in the invention
include polylactic acid based, polybutylene succinate based,
polyvinyl alcohol based, and acetylcellulose based biodegradable
resins. These may be used alone or in a mixture form.
[0035] In order to make the paper-resin composition into an
ecologically sound type, the finely cut paper product and the
synthetic resin therein are blended with each other to set the
amount of the synthetic resin into 50% or less by mass of the total
of the two. About the blending ratio therebetween, the ratio of the
finely cut paper product/the synthetic resin preferably ranges from
51/49% by mass to 70/30% by mass. If necessary, aids such as a
fluidity improver, an antioxidant for the resin or an antistatic
agent may be added as long as no effect is produced onto the
advantageous effects of the invention. A small amount of titanium
oxide or calcium carbonate may be added to the paper-resin
composition to improve the brightness. However, the white filler
does not produce an advantageous effect onto yellowing in which
water is involved, that is, yellowing based on immersion into water
although it appears that the white filler improves the brightness
of the paper-resin composition to improve the yellowing in the
appearance.
[0036] In the case that the paper-resin composition is a
composition made mainly of the finely cut paper product and a
biodegradable resin, the blending ratio for making the composition
into an ecologically sound type is not limited since the two are
each biodegradable. When the total amount of the biodegradable
resin and a natural organic material is 50% or more by mass, the
composition is in conformity with "GREEN PLA", which is
institutionalized by the Biodegradable Plastics Society. When the
biodegradable resin is polylactic acid, the use of the blend of the
resin with the finely cut paper product makes it possible to expect
an advantageous effect that the tensile strength, the flexural
modulus and the thermal deformation temperature of the
injection-molded product are made better than the use of polylactic
acid alone. Actually, the blending ratio of the finely cut paper
product to the biodegradable resin is decided, considering the
moldability and the quality required for the molded product.
Usually, the ratio of the finely cut paper product/the
biodegradable resin ranges from 20/80% by mass to 70/30% by mass.
In the same manner as described above, the aids or the white filler
may be appropriately used.
[0037] When a rosin based resin is added to the finely cut paper
product of the invention and the biodegradable resin, the fluidity
of the paper-resin composition is improved and further softness can
be given thereto. Examples of the rosin based resin that can be
used include gum rosin, wood rosin, tall oil rosin, and derivatives
thereof. Examples of the derivatives include derivatives subjected
to various stabilizing treatments, esterifying treatments, and
purifying treatments. Particularly preferred is a rosin ester
obtained by causing a rosin to react with various alcohols.
Examples of the rosin ester include polymerized rosin glycerin
ester, tall oil rosin glycerin ester, wood rosin glycerin ester,
partially-hydrogenated gum wood rosin glycerin ester, wood rosin
pentaerythritol ester, partially-hydrogenated rosin methyl ester,
and partially-dimerized rosin glycerin ester.
[0038] In this case, the blending ratio of the rosin based resin in
the paper-resin composition is preferably from 1 to 15% by mass. If
the ratio is less than 1% by mass, the fluidity-improving effect or
the softening effect is insufficient. If the ratio is more than 15%
by mass, the heat resistance may be deteriorated.
[0039] The process for producing the paper-resin composition of the
invention may be a method known in the prior art. For example, the
finely cut paper product and the synthetic resin or biodegradable
resin are weighed to set the ratio therebetween to a predetermined
ratio. Thereafter, the components are uniformly mixed by a Henschel
mixer or the like. This is made into a homogeneous form at a
temperature of 100 to 200.degree. C. by a kneading machine.
Thereafter, the resultant is continuously supplied into a feeder of
an extruder if necessary. In this way, the blend is preferably made
into pellets and granulized.
[0040] A molded product wherein the paper-resin composition of the
invention is used is obtained by molding the paper-resin
composition of the invention made into a pellet form by the same
plastic resin molding method as known in the prior art. The molded
product obtained by molding the ecologically sound paper-resin
composition of the invention is, for example, a cup, a dish, a tray
for food, a bowl, a comb, a winding bobbin, a hanger, a calendar
holder, and a toothbrush.
EXAMPLES
[0041] The invention will be more specifically described by the
following examples; however, the invention is not limited to these
examples. In the examples, the word "part(s)" and the symbol "%"
represent "part(s) by mass" and "% by mass", respectively unless
otherwise specified.
Example 1
[0042] Uncoated neutral woodfree paper containing 90% by mass of
hardwood bleached kraft pulp (LBKP) and 10% by mass of talc (trade
name: TALC KB, manufactured by Kamitalc Co.) and having an ISO
brightness of 80% was pulverized with a pulverizing device (CS
CUTTER, manufactured by Condux Co.), and the resultant was caused
to pass through a 100-mesh screen, thereby yielding a finely cut
paper product of Example 1. The apparent bulk specific gravity of
the finely cut paper product was 0.15. Next, to 100 parts by mass
of the finely cut paper product were added 5 parts by mass of
titanium oxide (trade name: TIPAQUE A-220, manufactured by Ishihara
Sangyo Kaisha, Ltd.) as a white filler, 5 parts by mass of a
modified polypropylene (PP) resin (trade name: YOUMEX1010,
manufactured by San Nopco, Ltd.), and 90 parts by mass of a
polypropylene (PP) resin (trade name: J-3054HP, manufactured by
Idemitsu Petrochemical Co., Ltd. Now, Idemitsu Kosan Co., Ltd.),
and then the components were uniformly mixed with each other by a
Henschel mixer. Thereafter, the resultant was charged into an
extruder so as to be made into pellets. In this way, a paper-resin
composition of Example 1 was yielded. A part of this paper-resin
composition was used, and an injection molding machine was used to
produce an injection-molded product for evaluation at a
cylinder-set temperature of 180.degree. C.
Example 2
[0043] A finely cut paper product and a paper-resin composition of
Example 2 were yielded in the same way as in Example 1 except that
there was used uncoated neutral woodfree paper containing 80% by
mass of hardwood bleached kraft pulp (LBKP), 10% by mass of
softwood bleached kraft pulp (NBKP) and 10% by mass of calcium
carbonate (trade name: TP121, manufactured by Okutama Kogyo Co.,
Ltd.) as a filler and having an ISO brightness of 83% and the paper
was pulverized. The apparent bulk specific gravity of the finely
cut paper product was 0.12. A part of this paper-resin composition
was used to produce an injection-molded product for evaluation in
the same way as in Example 1.
Example 3
[0044] A finely cut paper product and a paper-resin composition of
Example 3 were yielded in the same way as in Example 1 except that
there was used uncoated neutral woodfree paper containing 70% by
mass of hardwood bleached kraft pulp (LBKP), 15% by mass of
softwood bleached kraft pulp (NBKP) and 15% by mass of calcium
carbonate (trade name: TP121, manufactured by Okutama Kogyo Co.,
Ltd.) as a filler and having an ISO brightness of 85% and the paper
was pulverized. The apparent bulk specific gravity of the finely
cut paper product was 0.11. A part of this paper-resin composition
was used to produce an injection-molded product for evaluation in
the same way as in Example 1.
Example 4
[0045] To 100 parts by mass of the finely cut paper product yielded
in Example 1 were added 5 parts by mass of titanium oxide (trade
name: TIPAQUE A-220, manufactured by Ishihara Sangyo Kaisha, Ltd.)
as a white filler, and 200 parts by mass of polylactic acid (PLA)
(trade name: LACEA H-100, manufactured by Mitsui Chemicals, Inc.)
as a biodegradable resin, and then the components were uniformly
mixed by a Henschel mixer. Thereafter, the resultant was charged
into an extruder so as to be made into pellets. In this way, a
paper-resin composition of Example 4 was yielded. A part of this
paper-resin composition was used to produce an injection-molded
product for evaluation in the same way as in Example 1.
Example 5
[0046] A paper-resin composition of Example 5 was yielded in the
same way as in Example 4 except that the finely cut paper product
of Example 2 was used as a finely cut paper product. A part of this
paper-resin composition was used to produce an injection-molded
product for evaluation in the same way as in Example 1.
Example 6
[0047] A paper-resin composition of Example 6 was yielded in the
same way as in Example 4 except that the finely cut paper product
of Example 3 was used as a finely cut paper product. A part of this
paper-resin composition was used to produce an injection-molded
product for evaluation in the same way as in Example 1.
Example 7
[0048] To 100 parts by mass of the finely cut paper product yielded
in Example 1 were added 5 parts by mass of titanium oxide (trade
name: TIPAQUE A-220, manufactured by Ishihara Sangyo Kaisha, Ltd.)
as a white filler, 20 parts by mass of a rosin ester (trade name:
LACTCIZER GP2001, manufactured by Arakawa Chemical Industries,
Ltd.) and 180 parts by mass of polylactic acid (PLA) (trade name:
LACEAH-100, manufactured by Mitsui Chemicals, Inc.) as a
biodegradable resin, and then the components were uniformly mixed
by a Henschel mixer. Thereafter, the resultant was charged into an
extruder so as to be made into pellets. In this way, a paper-resin
composition of Example 7 was yielded. A part of this paper-resin
composition was used to produce an injection-molded product for
evaluation in the same way as in Example 1.
Example 8
[0049] A paper-resin composition of Example 8 was yielded in the
same way as in Example 7 except that the finely cut paper product
of Example 2 was used as a finely cut paper product. A part of this
paper-resin composition was used to produce an injection-molded
product for evaluation in the same way as in Example 1.
Example 9
[0050] A paper-resin composition of Example 9 was yielded in the
same way as in Example 7 except that the finely cut paper product
of Example 3 was used as a finely cut paper product. A part of this
paper-resin composition was used to produce an injection-molded
product for evaluation in the same way as in Example 1.
Comparative Example 1
[0051] A finely cut paper product and a paper-resin composition of
Comparative Example 1 were yielded in the same way as in Example 1
except that there was used uncoated neutral woodfree paper
containing 60% by mass of hardwood bleached kraft pulp (LBKP), 30%
by mass of softwood bleached kraft pulp (NBKP) and 10% by mass of
talc (trade name: TALC KB, manufactured by Kamitalc Co.) as a
filler and having an ISO brightness of 80% and the paper was
pulverized. The apparent bulk specific gravity of the finely cut
paper product was 0.08. A part of this paper-resin composition was
used to produce an injection-molded product for evaluation in the
same way as in Example 1.
Comparative Example 2
[0052] A finely cut paper product and a paper-resin composition of
Comparative Example 2 were yielded in the same way as in Example 1
except that there was used uncoated neutral woodfree paper
containing 80% by mass of hardwood bleached kraft pulp (LBKP), 10%
by mass of groundwood pulp (GP), and 10% by mass of talc (trade
name: TALC KB, manufactured by Kamitalc Co.) as a filler and having
an ISO brightness of 70% and the paper was pulverized. The apparent
bulk specific gravity of the finely cut paper product was 0.12. A
part of this paper-resin composition was used to produce an
injection-molded product for evaluation in the same way as in
Example 1.
Comparative Example 3
[0053] A finely cut paper product and a paper-resin composition of
Comparative Example 3 were yielded in the same way as in Example 1
except that there was used uncoated neutral woodfree paper
containing 60% by mass of hardwood bleached kraft pulp (LBKP), 30%
by mass of groundwood pulp (GP), and 10% by mass of calcium
carbonate (trade name: TP121, manufactured by Okutama Kogyo Co.,
Ltd.) as a filler and having an ISO brightness of 64% and the paper
was pulverized. The apparent bulk specific gravity of the finely
cut paper product was 0.11. A part of this paper-resin composition
was used to produce an injection-molded product for evaluation in
the same way as in Example 1.
Comparative Example 4
[0054] A finely cut paper product and a paper-resin composition of
Comparative Example 4 were yielded in the same way as in Example 1
except that there was used coated paper having a pigment-coated
layer on a base paper containing 90% by mass of hardwood bleached
kraft pulp (LBKP) and 10% by mass of talc (trade name: TALC KB,
manufactured by Kamitalc Co.) as a filler and having an ISO
brightness of 78% and the paper was pulverized. The apparent bulk
specific gravity of the finely cut paper product was 0.15. A part
of this paper-resin composition was used to produce an
injection-molded product for evaluation in the same way as in
Example 1.
Comparative Example 5
[0055] A finely cut paper product and a paper-resin composition of
Comparative Example 5 were yielded in the same way as in Example 1
except that waste newspaper was used and the paper was pulverized.
The apparent bulk specific gravity of the finely cut paper product
was 0.08. A part of this paper-resin composition was used to
produce an injection-molded product for evaluation in the same way
as in Example 1.
[0056] The papers used in Examples 1 to 9 and Comparative Examples
1 to 5, finely cut paper products and the paper-resin compositions
yielded therein were evaluated by methods described below. The
results are shown in Table 1.
[0057] <ISO Brightness>
[0058] It was measured with a PF-10 manufactured by Nippon Denshoku
Industries Co., Ltd. The method for operating the device was in
accordance with maker's operation manual, and the measurement was
made in accordance with JIS P 8148:2001 "Paper, board and
pulps--Measurement of diffuse blue reflectance factor(ISO
brightness)".
[0059] <Apparent Bulk Specific Gravity>
[0060] Each of the resultant finely cut paper products was put into
a 2-liter measuring cylinder, and the mass thereof was measured.
The mass per unit volume was then calculated.
[0061] <MFR (Melt Flow Rate)>
[0062] It was measured in accordance with ASTMD 1238-98 "Standard
Test Method for Flow Rates of Thermoplastics by Extrusion
Plastometer" under the following conditions: the unit of
g/10-minutes, test temperature=190.degree. C., and test load=10
kg.
[0063] <Kneading-Workability>
[0064] The mixing evenness obtained by the Henschel mixer was
evaluated on the following criterion:
[0065] X: Uneven stirring was observed and felt with the naked
eye.
[0066] .largecircle.: Good stirring was observed and felt with the
naked eye.
[0067] <Formation of Test Piece>
[0068] Each multi-purpose test piece (JIS K 7139 A-model) and each
plate, 80.times.80.times.3 (mm) in thickness, were formed by means
of an F85 manufactured by Glockner Co.
[0069] <Color of Injected Molded Plate>
[0070] The molded plate, 80.times.80.times.3 (mm) in thickness, was
judged in accordance with the following criterion on the basis of
feeling obtained by seeing it with the naked eye:
[0071] xx: Clearly yellowish
[0072] x: Slightly yellowish
[0073] .largecircle.: Non-yellowish, and good
[0074] <Injection Molding Odor>
[0075] An odor from the molded plate, 80.times.80.times.3 (mm) in
thickness, was judged in accordance with the following
criterion:
[0076] xx: A paper-burnt odor, and an offensive odor originating
from a latex-decomposed gas were generated.
[0077] x: A paper-burnt odor was slightly generated.
[0078] .largecircle.: No odor was favorably generated.
[0079] <Injection Molding Water Yellowing>
[0080] Into 30 ml of distilled water was immersed 50 g of an
injection molded product cut off from the molded plate,
80.times.80.times.3 (mm) in thickness, and then the product was
kept at 35.degree. C. for 2 days. Thereafter, the water was
filtrated, and the degree of coloring of the water phase was
evaluated on the basis of feeling obtained by seeing the water with
the naked eye. The evaluation by the feeling was judged on the
following criterion:
[0081] xx: Yellow
[0082] x: Light yellow
[0083] .largecircle.: Colorlessness
[0084] <Tensile Strength>
[0085] It was measured in accordance with JIS K 7162
"Plastics--Determination of tensile properties-Part 2: Test
conditions for moulding and extrusion plastics".
[0086] <Bending Strength>
[0087] It was measured in accordance with JIS K 7171
"Plastics--Determination of flexural properties".
[0088] <Flexural Modulus>
[0089] It was measured in accordance with JIS K 7171
"Plastics--Determination of flexural properties".
[0090] <IZOD (Izod Impact Test)>
[0091] It was measured in accordance with JIS K 7110
"Plastics--Determination of Izod impact strength" (without any
notch)<
[0092] HDT (Heat Distortion Temperature)>
[0093] It was measured in accordance with JIS K 7191-2
"Plastics--Determination of temperature of deflection under
load-Part 2: Plastics and ebonite".
TABLE-US-00001 TABLE 1 Finely Cut ISO Waste Whole Filler Modified
Resin PP Paper Product Bright- Coated News- (titanium PP Ester
Resin PLA Apparent bulk LBKP NBKP CIP Filler ness Layer paper
oxide) (*1) (*2) (*3) (*4) specific gravity Example 1 90 Talc 10 80
Not 5 5 90 0.15 formed Example 2 80 10 Calcium 83 Not 5 5 90 0.12
carbonate 10 formed Example 3 70 15 Calcium 85 Not 5 5 90 0.11
carbonate 15 formed Example 4 90 Talc 10 80 Not 5 200 0.15 formed
Example 5 80 10 Calcium 83 Not 5 200 0.12 (*5) carbonate 10 formed
Example 6 70 15 Calcium 85 Not 5 200 0.11 (*5) carbonate 15 formed
Example 7 90 Talc 10 80 Not 5 20 180 0.15 (*5) formed Example 8 80
10 Calcium 83 Not 5 20 180 0.12 (*5) carbonate 10 formed Example 9
70 15 Calcium 85 Not 5 20 180 0.11 (*5) carbonate 15 formed
Comparative 60 30 Talc 10 80 Not 5 5 90 0.08 Example 1 formed
Comparative 80 10 Talc 10 70 Not 5 5 90 0.12 Example 2 formed
Comparative 60 30 Calcium 64 Not 5 5 90 0.11 Example 3 carbonate 10
formed Comparative 90 Talc 10 78 Formed 5 5 90 0.15 Example 4
Comparative 100 5 5 90 0.08 Example 5 HOT MFR Injection Molding
Tensile Bending Flexural (0.48 Kneading- g/10-minutes Plate Water
Strength Strength Modulator IZOD MPa) workability 190.degree. C. 10
kg color Odor yellowing MPa MPa MPa J/M .degree. C. Example 1
.smallcircle. 5 .smallcircle. .smallcircle. .smallcircle. 40 59
4400 52 152 Example 2 .smallcircle. 4 .smallcircle. .smallcircle.
.smallcircle. 40 59 4100 48 155 Example 3 .smallcircle. 3
.smallcircle. .smallcircle. .smallcircle. 45 64 4900 44 155 Example
4 .smallcircle. 15 .smallcircle. .smallcircle. .smallcircle. 52 81
6400 57 155 Example 5 .smallcircle. 12 .smallcircle. .smallcircle.
.smallcircle. 70 97 9000 60 152 (*5) Example 6 .smallcircle. 11
.smallcircle. .smallcircle. .smallcircle. 56 99 6900 70 152 (*5)
Example 7 .smallcircle. 20 .smallcircle. .smallcircle.
.smallcircle. 39 54 5400 16 135 (*5) Example 8 .smallcircle. 20
.smallcircle. .smallcircle. .smallcircle. 40 65 5500 18 136 (*5)
Example 9 .smallcircle. 11 .smallcircle. .smallcircle.
.smallcircle. 41 68 5700 19 138 (*5) Comparative x 1 .smallcircle.
.smallcircle. .smallcircle. 50 59 5000 47 155 Example 1 Comparative
.smallcircle. 5 .smallcircle. .smallcircle. x 40 59 4100 48 153
Example 2 Comparative .smallcircle. 4 x x x x 43 60 4900 80 155
Example 3 Comparative .smallcircle. 5 .smallcircle. x x
.smallcircle. 43 60 4900 50 156 Example 4 Comparative x 0.5 x x x x
x x 50 60 5000 29 156 Example 5 (*1): Modified PP: YOUMEX 1010(SAN
NOPCO) (*2): Resin ester: LACTSIZER GP2001 (Arakawa Chemical
Industries) (*3): PP resin: J-3054HP (Idemitsu Petrochemical) (*4):
PLA: LACEA H-100(Mitsui Chemicals) (*5): Examples 5 to 9: Annealing
treatment at 85.degree. C. for 30 minutes
[0094] In Comparative Example 1, the paper wherein the content by
percentage of the LBKP was small was used; thus, the apparent bulk
specific gravity was small and the kneading-workability was poor.
In Comparative Example 2, the paper containing the GP was used;
thus, slightly yellowing was generated by water although the ISO
brightness of the paper was high. In Comparative Example 3, the
paper containing a larger amount of the GP than in Comparative
Example 2 was used; thus, the ISO brightness was low and the plate
color was yellowish, and further yellowing based water was
generated. Furthermore, a paper-burnt odor was slightly felt when
the composition was molded. In Comparative Example 4, the paper
having the pigment-coated layer was used; thus, a paper-burnt odor
and an offensive odor originating from a latex decomposed gas were
felt when the composition was molded. In Comparative Example 5, the
waste newspaper was used; thus, the kneading-workability was poor,
the plate color was clearly yellowish, and yellowing based on water
was generated.
[0095] On the other hand, as is evident form the results in Table
1, in each of Examples 1 to 9, a finely cut paper product is
obtained which is good in workability when a paper-resin
composition made of a mixture of a resin and a natural fiber is
produced. In an ecologically sound paper-resin composition using
the finely cut paper product, the fluidity is improved, and the
moldability is improved when the composition is subjected to a
processing such as injection molding. On the basis of these
results, the blending ratio of the finely cut paper product can be
made as high as 50% or more by mass. As a result, a paper-resin
composition more friendly with the environment can be produced. It
is also possible to yield an ecologically sound paper-resin
composition which contains a finely cut paper product but causes a
remarkable decrease of yellowing based on heat in a processing
step, in particular, yellowing in which water is involved, and
simultaneously restrains the generation of an odor. For example,
the composition can be applied to the field of food; thus, the
commercial value of the composition can be made high.
* * * * *