U.S. patent application number 11/489841 was filed with the patent office on 2007-02-22 for biodegradable resin composition.
Invention is credited to Sang-hwan Lee, Young-kwan Yi.
Application Number | 20070043148 11/489841 |
Document ID | / |
Family ID | 37668977 |
Filed Date | 2007-02-22 |
United States Patent
Application |
20070043148 |
Kind Code |
A1 |
Yi; Young-kwan ; et
al. |
February 22, 2007 |
Biodegradable resin composition
Abstract
This invention provides a biodegradable resin composition and a
biodegradable molding using the same and in particular, it not only
have satisfactory biodegradability, processability and properties
required for biodegradable resins by comprising cellulose diacetate
as a main component but also can lower manufacturing costs and
prevent environmental contamination by preparing the biodegradable
resins by reusing a cause factor of environmental
contamination.
Inventors: |
Yi; Young-kwan; (Seoul,
KR) ; Lee; Sang-hwan; (Seoul, KR) |
Correspondence
Address: |
CANTOR COLBURN, LLP
55 GRIFFIN ROAD SOUTH
BLOOMFIELD
CT
06002
US
|
Family ID: |
37668977 |
Appl. No.: |
11/489841 |
Filed: |
July 20, 2006 |
Current U.S.
Class: |
524/47 |
Current CPC
Class: |
C08L 1/12 20130101; C08L
2666/26 20130101; C08L 2666/26 20130101; C08L 2201/06 20130101;
C08K 5/053 20130101; C08L 1/12 20130101; C08L 97/02 20130101; C08K
5/11 20130101; C08K 5/103 20130101; C08L 101/16 20130101; C08L
97/02 20130101 |
Class at
Publication: |
524/047 |
International
Class: |
D21H 19/54 20060101
D21H019/54 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 20, 2005 |
KR |
10-2005-0065780 |
Claims
1. A biodegradable resin composition comprising a cellulose
diacetate as a main component.
2. The biodegradable resin composition according to claim 1 wherein
the cellulose diacetate is an ethyl cellulose having a molecular
weight of 10,000 to 500,000.
3. The biodegradable resin composition according to claim 1 wherein
the biodegradable resin composition comprises: a) 50 to 90 parts by
weight of a cellulose diacetate; and b) 10 to 50 parts by weight of
a plasticizer.
4. The biodegradable resin composition according to claim 1 wherein
the plasticizer is selected from the group consisting of triacetin
(TA), triethyl citrate (TEC), glycerin and a mixture thereof.
5. The biodegradable resin composition according to claim 1 wherein
the cellulose diacetate is obtained from a waste cigarette
filter.
6. The biodegradable resin composition according to claim 1 wherein
the biodegradable resin composition further comprises a clay
mineral, degradation catalyst or processing aid.
7. The biodegradable resin composition according to claim 1 wherein
the biodegradable resin composition further comprises a natural
vegetable fiber.
8. A biodegradable molding prepared by kneading, extruding and
injecting the biodegradable resin composition of claim 1.
9. The biodegradable molding according to claim 8 wherein the
biodegradable molding is a film for semiconductor packaging,
container, cup, spoon, fork, knife, toothbrush, straw, paper cup,
paper coating for the manufacture of paper plates, mulching film,
plant port, clip, garbage bag, compost bag, shrink wrap film,
wrapping film, syringe for animal injection, mouthpiece for
endoscope, modifier for hard biodegradable plastics, golf tee, fish
net, fishing line, bottles or stationery.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a biodegradable resin
composition and a biodegradable molding using the same and more
particularly, it relates to a biodegradable resin composition
comprising cellulose diacetate as a main component, which can not
only satisfy the biodegradability, processability and properties
required for a biodegradable resin but also lower manufacturing
costs and prevent environmental contamination by producing the
biodegradable resin by reusing a cause factor of environmental
contamination and a biodegradable molding using the same.
[0003] 2. Description of Related Art
[0004] As plastics are light and strong and they are easy to be
processed and not easily degraded, their consumption from
industrial materials to disposable products and wrapping materials
is continuously increasing. Hard wastes including such plastics are
disposed by landfill or incineration after their use, or reused by
recycling them. However, the disposal of wastes by landfill,
incineration, etc. gives rise to environmentally severe damage.
Accordingly, to solve the environment issue, various biodegradable
plastics that keep their function and structure during their use
but can be degraded into water and carbon dioxide by microorganism
once wasted are being produced.
[0005] For example, U.S. Pat. Nos. 5,234,977, 5,256,711, 5,264,030,
5,292,782, 5,334,634, 5,461,093, 5,461,094, 5,569,692, 5,616,671,
5,696,186, 5,869,647, and 5,874,486 disclose methods of preparing
biodegradable plastics by mixing a starch which is inexpensive and
easily biodegradable with common resins such as polyethylene,
polypropylene and polystyrene, and polyester-based matrix resins.
However, as the starch is added, a plasticizer is to be added,
which causes discoloring and bad fume during processing and the
properties of the plastics are remarkably deteriorated.
[0006] Further, U.S. Pat. Nos. 4,133,784 and 4,337,181 disclose
methods of preparing films by adding pregelatinized starches to
ethylene-acrylic acid copolymers. However, the ethylene-acrylic
acid copolymers are expensive and the properties of the produced
films are extremely fragile for practical use, and their
biodegradability is not good.
[0007] Further, U.S. Pat. Nos. 5,254,607, 5,256,711 and 5,258,430
disclose the use of a pregelatinized starch, but they require a
separate apparatus for adding water and a plasticizer in a large
amount so as to pregelatinize starch and also, the degradability of
the ethylene-vinyl alcohol copolymers which are synthetic resins
used to increase properties and dimension stability has not been
verified.
[0008] Also, Korean Patent Laid-Open Nos. 1994-0011542,
1994-0011556, and 1994-0011558 attempted reaction extrusion by use
of an organic acid catalyst and binding agent to induce the
chemical binding of starch and polyethylene. However, unreacted
coarse monomers are likely to remain, and in the case that the
content of the starch is more than 30%, mechanical properties are
remarkably reduced, and the polyethylene which is used as a matrix
resin is not degraded and remains.
[0009] Hence, researches about methods of preparing biodegradable
resins using cellulose derivatives have been conducted and
especially, the researches about the biodegradable resins using
cellulose acetate among the cellulose derivatives have been mainly
performed.
[0010] The cellulose acetate, a conversion form into an acetic
ester of cellulose, has been known to be inherently biodegradable
but in fact, its biodegradability is not good. Thus, although
molding products comprising the cellulose acetate are laid under
the grounds, they maintain the prototype of the molding products
until 1 or 2 years and it takes considerably long time for the
molding products to be completely biodegraded. Also, the molding
products are sometimes landfilled as wastes, or left in nature
environment, not being recovered as wastes.
[0011] Accordingly, researches about methods for improving the
biodegradability of the cellulose acetate are in progress. Japanese
Patent Laid Open No. 6-199901 discloses a method of regulating the
biodegradability of the cellulose acetate by adding an acid
compound having a higher acid dissociation constant than acetic
acid to the cellulose acetate. However, in this method, at the
point when the acid compound is added to the cellulose acetate, the
cellulose acetate is chemically hydrolyzed by the influence of the
acid compound and this hydrolysis reaction generates acetic acid,
which gives strong acetic acid odor to the cellulose acetate
products.
[0012] Therefore, studies about methods of preparing biodegradable
plastics using different kinds of cellulose derivatives other than
the cellulose acetate have been incessantly conducted and more
progressive studies are in need.
SUMMARY OF THE INVENTION
[0013] In order to solve the problems of the prior arts, it is an
object of the invention to provide a biodegradable resin
composition comprising a cellulose (di)acetate as a main component,
which satisfies the biodegradability, processability and properties
required for a biodegradable resin and from which acetic acid odor
is removed, and a biodegradable molding using the same.
[0014] Also, it is another object of the invention to provide a
biodegradable resin composition which can lower the manufacturing
costs of the biodegradable resin composition to be produced and
prevent environmental contamination in advance by reusing a cause
factor inducing environmental contamination and a biodegradable
molding using the same.
[0015] It is still another object of the invention to provide a
biodegradable resin composition capable of preventing environmental
contamination because the container is degraded under the ground or
in the air within a short period when landfilled after its use, a
method of preparing a biodegradable molding using the same and the
biodegradable molding.
[0016] To achieve the aforementioned objects, the present invention
provides a biodegradable resin composition comprising a cellulose
diacetate as a main component.
[0017] Preferably, the molecular weight of the cellulose diacetate
is 10,000 to 500,000.
[0018] Also, more preferably, the biodegradable resin composition
comprises:
[0019] a) 50 to 90 parts by weight of a cellulose diacetate;
and
[0020] b) 10 to 50 parts by weight of a plasticizer.
[0021] Further, the invention provides a biodegradable molding
prepared by kneading and extruding the biodegradable resin
composition.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a graph showing of the biodegradability of a
biodegradable film prepared by using an embodiment of the invention
comprising cellulose diacetate, comparing with that of cellulose
which is a standard material.
[0023] FIG. 2 is a graph showing the biodegradability of PLA which
is a commonly used biodegradable material, comparing with that of
cellulose which is a standard material.
DETAILED DESCRIPTION OF THE INVENTION
[0024] This invention is further described in detail.
[0025] The inventors found that a cellulose diacetate can be
biodegraded and it has a remarkably low melting point and thus has
an excellent processability while possessing superior properties
and accordingly, they have completed the invention.
[0026] The biodegradable resin composition of the invention is
characterized by comprising a cellulose diacetate that is a
biodegradable resin, as a main component.
[0027] Preferably, the biodegradable resin composition of the
invention comprises a cellulose diacetate and plasticizer, and
biodegradable moldings can be prepared by evenly mixing the
biodegradable resin composition and kneading and extruding the
mixed composition.
[0028] The cellulose diacetate is contained in the biodegradable
resin composition preferably in an amount of 50 to 90 parts by
weight. Within the above ranges, satisfactory processability as a
biodegradable resin composition as well as the properties of
moldings can be obtained.
[0029] Preferably, the cellulose diacetate can be obtained from a
waste cigarette filter which is a cause factor of environmental
contamination, and the manufacturing costs of the biodegradable
resin compositions can be remarkably lowered by preparing the
biodegradable resin compositions by recycling the cellulose
diacetate of the waste cigarette filters and environmental
contamination can be prevented in advance.
[0030] The plasticizer used in the invention makes molding,
injection, etc. easy when the biodegradable moldings are prepared
and it improves glass transition temperature (Tg), tensile
strength, Young's modulus, etc. of the cellulose diacetate.
[0031] For the plasticizers, triacetin (TA), triethyl citrate
(TEC), or glycerin can be suitably used, epoxidized soybean oil
(ESO) as a secondary plasticizer can be added thereto and
preferably, it is preferable to use triacetin.
[0032] The plasticizer is contained in the biodegradable resin
composition of the invention preferably in an amount of 10 to 50
parts by weight, and the above range is preferable in aspect of the
easiness of molding and injection when the moldings are
prepared.
[0033] The biodegradable resin composition comprising the above
components may further comprise clay minerals such as
montmorillonite and bentonite, additives such as a degradation
catalyst or processing aid, etc. if necessary and their amount is
preferably 0.1 to 10 parts by weight.
[0034] For the catalysts, a latent heat catalyst can be used to
cause the ring opening polymerization of epoxidized soybean when
the epoxidized soybean is contained as a plasticizer.
[0035] The clay minerals have excellent hygroscopic property due to
their laminated structure and accordingly, they render the moldings
prepared with the biodegradable resin composition of the invention
to be readily degraded even in the water. In particular, the
montmorillonite is preferably used as a clay mineral.
[0036] Also, when the clay minerals are used in the biodegradable
resin composition of the invention, it is preferable to mix the
clay minerals with the plasticizer and disperse them using an
ultrasonic machine before they are added to the biodegradable resin
composition.
[0037] Further, the invention may further comprise a natural
vegetable fiber as a filling agent within the biodegradable resin
composition in the preparation of the biodegradable resin
composition. Specific examples of the natural vegetable fiber are
coconut fiber, hemp fiber, ramie fiber, sisal fiber, henequen
fiber, pineapple leaf fiber, cotton fiber, coier fiber, rice straw,
etc. and it is preferable to have an average diameter of 10 to 500
.mu.m or so. Also, the filling agent is contained preferably in an
amount of 1 to 50 parts by weight of 100 parts by weight of the
biodegradable resin composition, and in this case, it is advisable
to maintain the content of the plasticizer in at least 10% by
weight of the biodegradable resin composition. If the filling agent
is used, mechanical strength can be complemented and the use of the
natural vegetable fibers that are inexpensive can much lower the
manufacturing costs of the biodegradable resin composition.
[0038] Further, the invention provides a biodegradable molding
characterized in that it is prepared by kneading and extruding the
biodegradable resin composition comprising the aforementioned
components.
[0039] For the kneading and extrusion, conventional methods used to
knead and extrude biodegradable resin compositions can be applied
and for example, a twin screw extruder or batch mixer can be
used.
[0040] Preferably, the temperature during the kneading process is
25.about.120.degree. C. as the melting point of the cellulose
diacetate is low and more preferably, it is 25.about.100.degree.
C.
[0041] Also, after kneaded at the above temperature, it can be
molded into moldings preferably at the temperature of
160.about.220.degree. C. using a common extruder.
[0042] The biodegradable moldings prepared by the aforementioned
method can be applied to films for semiconductor packaging,
disposable products such as a variety of containers, cups, spoons,
forks, knives, toothbrushes and straws, paper cups, melty coatings
such as paper coatings for the manufacture of paper plates,
mulching films, agriculture and gardening supplies such as plant
ports, clips, etc. garbage bags, compost bags, shrink wrap films,
wrapping films, medical supplies such as syringes for animal
injection, mouthpieces for endoscope, modifiers for hard
biodegradable plastics, golf tee, fish net, fishing line, bottles,
a variety of stationery and so on.
[0043] The biodegradable resin composition in accordance with the
invention is melted at a melting point remarkably lower than the
melting point required in the manufacture of cellulose derivatives
used as a substance of prior biodegradable plastics so that it is
easy to be prepared into moldings and at the same time, it has
properties equal to those of the moldings prepared by using the
prior biodegradable resins. In addition, it can in advance prevent
environmental contamination by reusing a cause factor of
environmental contamination and remarkably lower the manufacturing
costs of the biodegradable resin compositions. Also, as the
biodegradable moldings prepared by using the biodegradable resin
compositions of the invention can be degraded under the ground or
in the air within a short period when landfilled after their use,
they have an advantage in that they can prevent environmental
contamination.
[0044] For better understanding of the present invention, preferred
embodiments follow. The following examples are intended to merely
illustrate the invention without limiting the scope of the
invention.
EXAMPLES
Example 1
[0045] After 70 parts by weight of cellulose diacetate having a
molecular weight of 202,332 (Eastman Co., Ltd.), and 30 parts by
weight of triacetin (Mw. 218.21, major component
C.sub.9H.sub.14O.sub.6), Dae Shin Chemical Ind. Co., Ltd.) as a
plasticizer were evenly mixed, the mixture was kneaded for 3 hours
at the temperature of 100.degree. C. and melted in Haake rheocord
system of 200.degree. C. thereby to prepare a blending mixture.
Examples 2 to 8 and Comparative Examples 1 to 6
[0046] With the exception that the compositions and ratios as shown
in Table 1 below were used, blending mixtures were prepared by
carrying out the same method as above Example 1. TABLE-US-00001
TABLE 1 Cellulose (Parts by Plasticizer Weight) TA TEC GC ESO BET
EX. 1 CDA.sup.1 70 30 EX. 2 CDA.sup.1 80 20 EX. 3 CDA.sup.1 80 20
EX. 4 CDA.sup.1 80 20 EX. 5 CDA.sup.1 80 10 10 EX. 6 CDA.sup.2 80
20 EX. 7 CDA.sup.2 70 20 10 EX. 8 CDA.sup.3 80 20 EX. 9 CDA.sup.3
70 30 COM. EX. 1 CA 90 10 COM. EX. 2 CA 80 20 COM. EX. 3 CA 70 30
COM. EX. 4 pure PP COM. EX. 5 pure PLA Note CDA.sup.1: Cellulose
(Di)Acetate(Mn ca. 202,332 g mol.sup.-1, 54.5 wt. % acetyl content,
Tg 188.degree. C., Eastman Co., Ltd) CDA.sup.2: Recycling fabric
CDA (SK) CDA.sup.3: Recycling fiber CDA (SK) CA: Cellulose
acetate(Mn ca. 50,000 g mol.sup.-1, 39.7 wt. % acetyl content, Tg
188.degree. C., Aldrich Co., Ltd.) PP: Polypropylene (grade H1500,
Hyundai) PLA: Polylacetic acid (Mn 83,000 g mol.sup.-1 , Mw 153000
g mol.sup.-1 Cargill-Dow Co., Ltd.) TA: Triacetin(Mw. 218.21), Dae
Shin Chemical Ind. Co., Ltd. TEC: Triethyl citrate(Mw. 276.29),
Aldrich Co., Ltd. ESO: ShinDongBang Coroperation GC: Glycerin
[0047] The blending mixtures prepared by melting the biodegradable
resin composition in Haake rheocord system in Examples 1 to 9 were
extruded for 10 minutes at the melting points of the blending
mixtures using Carver laboratory press equipped with a temperature
control device thereby to prepare initial films having a width of
10 cm, a height of 10 cm and a thickness of 300 .mu.m. The prepared
films were cut into ones having a width of 0.5 cm and a height of 4
cm and their glass transition temperature and modulus were measured
by Dynamic Mechanical Analyzer. The results are shown in Table 2
below. TABLE-US-00002 TABLE 2 Glass transition temperature (Tg) and
Young's modulus measured from MDA Young's modulus EX./COM. EX. Tg
(.degree. C.) (GPa) EX. 1 97 1.50 EX. 2 108 1.55 EX. 3 138.5 1.72
EX. 4 146.9 1.64 EX. 5 141.9 1.91 EX. 6 89.9 1.34 EX. 8 92.8 1.34
COM. EX. 2 206.3 2.51
[0048] As shown in Table 2 above, the working Examples of the
invention had remarkably lower Tg and Young's modulus than
Comparative Example in which cellulose acetate was used and thus
they could be very easily processed.
[0049] In addition, to measure mechanical properties of the working
Examples of the invention and Comparative Examples, tensile
specimen were prepared according to ASTM D1708 and ASTM D638,
wherein the injection pressure was 750-900 psi, injection time was
3 seconds, the temperature of cylinder was 180-200.degree. C. and
cycle time was 2 min. The mechanical strength of the films prepared
above was measured by the machine named LR30K-plus from LLOYD, Inc.
10 Specimen in each example were fabricated and then tested. The
average value was taken and the results are shown in Table 3 below.
TABLE-US-00003 TABLE 3 Young's Tensile Strength Elongation modulus
EX. (MPa) (%) (MPa) EX. 1 72 8 2300 EX. 2 131 8 3671 EX. 4 90 5
2964 EX. 9 73 6 2254 COM. EX. 5 84 5 2633
[0050] As shown in Table 3 above, the biodegradable resin
compositions of the inventions showed properties similar to
Comparative Example 5 in which the prior biodegradable resin was
used.
[0051] Also, in order to examine the biodegradability of the
biodegradable resin compositions of the invention, the
biodegradable resin composition of Example 2 was subject to
experiment according to KS M 3100-1 (ISO 14855) provision, and the
biodegradability test was carried out in composting conditions. The
composition of Comparative Example 5 was tested likewise. As of
cellulose which is a standard material and Example 2 and
Comparative Example 5, their aerobic biodegradability and collapse
rate were measured in the composting conditions and the quantity of
the generated carbon dioxide was measured by titration.
[0052] FIG. 1 showed the biodegradability of Example 2 of the
invention and cellulose which is a standard material over time and
FIG. 2 showed the biodegradability of Comparative Example 5 and the
cellulose which is a standard material over time.
[0053] As shown in FIG. 1 and FIG. 2, the biodegradable resin
composition of the invention showed biodegradability almost equal
to that of Comparative Example 5 wherein the commonly used
biodegradable resin composition was used.
[0054] The biodegradable resin composition in accordance with the
invention can remarkably lower the manufacturing costs when
compared with the cellulose acetate which has been used as
biodegradable plastic materials, can prevent environmental
contamination by reusing the cause factor of environmental
contamination, remarkably improves the properties, is easy to be
prepared into moldings at a low temperature due to its low melting
point, and has considerably improved properties when compared with
prior biodegradable moldings using starch.
* * * * *