U.S. patent application number 14/913994 was filed with the patent office on 2016-07-21 for foamable resin composition for foam sheet, foam sheet, process for preparing particulate polylactic acid and process for preparing foam sheet.
This patent application is currently assigned to LG Hausys, Ltd.. The applicant listed for this patent is LG HAUSYS, LTD.. Invention is credited to Kyoung-Min KANG, Sung-Yong KANG, Hea-Won KWON, Min-Hee LEE, Jun-Beom SHIN.
Application Number | 20160208070 14/913994 |
Document ID | / |
Family ID | 52586970 |
Filed Date | 2016-07-21 |
United States Patent
Application |
20160208070 |
Kind Code |
A1 |
SHIN; Jun-Beom ; et
al. |
July 21, 2016 |
FOAMABLE RESIN COMPOSITION FOR FOAM SHEET, FOAM SHEET, PROCESS FOR
PREPARING PARTICULATE POLYLACTIC ACID AND PROCESS FOR PREPARING
FOAM SHEET
Abstract
Disclosed herein is a foamable resin composition for a foam
sheet including polylactic acid resin particles, each of the
particles having a particle size of about 1 .mu.m to about 100
.mu.m. A process for preparing a particulate polylactic acid resin
includes: introducing a polylactic acid resin and then forming a
molten polylactic acid spray solution; and injecting the molten
polylactic acid spray solution by a melt spray method and
simultaneously cooling the molten polylactic acid spray solution to
obtain a particulate polylactic acid. In addition, disclosed herein
is a process for preparing a foam sheet using the foamable resin
composition for a foam sheet including a polylactic acid resin.
Inventors: |
SHIN; Jun-Beom; (Suwon-si,
Gyeonggi-do, KR) ; KANG; Sung-Yong; (Anyang-si,
Gyeonggi-do, KR) ; LEE; Min-Hee; (Gunpo-si,
Gyeonggi-do, KR) ; KWON; Hea-Won; (Seoul, KR)
; KANG; Kyoung-Min; (Seoul, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LG HAUSYS, LTD. |
Seoul |
|
KR |
|
|
Assignee: |
LG Hausys, Ltd.
Seoul
KR
|
Family ID: |
52586970 |
Appl. No.: |
14/913994 |
Filed: |
August 29, 2014 |
PCT Filed: |
August 29, 2014 |
PCT NO: |
PCT/KR2014/008058 |
371 Date: |
February 24, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29B 9/12 20130101; B29C
48/0012 20190201; C08J 2367/04 20130101; B29B 9/10 20130101; B29K
2105/251 20130101; B29C 48/305 20190201; B29C 44/505 20161101; B29K
2067/046 20130101; C08J 5/18 20130101; B01J 2/02 20130101; C08J
3/12 20130101; C08J 3/122 20130101; B29C 48/0021 20190201; B05B
5/001 20130101; B29C 48/08 20190201; B29C 48/04 20190201 |
International
Class: |
C08J 9/28 20060101
C08J009/28; B29B 9/12 20060101 B29B009/12; C08J 3/12 20060101
C08J003/12 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 29, 2013 |
KR |
10-2013-0103466 |
Claims
1. A foamable resin composition for a foam sheet comprising
polylactic acid resin particles, each of the particles having a
particle size of 1 .mu.m to 100 .mu.m.
2. The foamable resin composition according to claim 1, wherein a
foam sheet prepared by molding the composition comprises a
polylactic acid resin having a weight average molecular weight of
100,000 to 200,000.
3. The foamable resin composition according to claim 1, wherein the
composition is a suspension in which the polylactic acid resin
particles are dispersed in a liquid solvent.
4. A foam sheet comprising polylactic acid resin particles, each of
the particles having a particle size of 1 .mu.m to 100 .mu.m.
5. The foam sheet according to claim 4, wherein the foam sheet
comprises a polylactic acid resin having a weight average molecular
weight of 100,000 to 200,000.
6. A process for preparing a particulate polylactic acid resin
comprising: introducing a polylactic acid resin and then forming a
molten polylactic acid spray solution; and spraying the molten
polylactic acid spray solution by a melt spray method and
simultaneously cooling the molten polylactic acid spray solution to
obtain a particulate polylactic acid.
7. The process according to claim 6, wherein the polylactic acid
resin is introduced into an extruder, and then transferred to an
spray nozzle and heated in the spray nozzle to form the molten
polylactic acid spray solution.
8. The process according to claim 7, wherein the polylactic acid
resin in the form of pellet or powder is introduced into the
extruder.
9. The process according to claim 8, wherein the molten polylactic
acid spray solution is introduced into the spray nozzle together
with an air and then discharged.
10. The process according to claim 9, wherein a temperature of the
air that is injected into the spray nozzle is of 300.degree. C. to
500.degree. C., a pressure of the air that is injected into the
spray nozzle is of 100 psi to 1,000 psi, and an injection speed of
the air that is injected into the spray nozzle is of 10 m/s to 50
m/s.
11. The process according to claim 7, wherein a temperature of the
spray nozzle is of 200.degree. C. to 400.degree. C.
12. The process according to claim 7, wherein a pressure of the
spray nozzle is of 10 psi to 1,000 psi.
13. The process according to claim 7, wherein a diameter of the
spray nozzle is of 0.5 mm to 3.0 mm.
14. The process according to claim 6, wherein the molten polylactic
acid spray solution comprises at least one additive selected from
the group consisting of a lubricant, a plasticizer, and a
combination thereof.
15. The process according to claim 6, wherein the molten polylactic
acid spray solution has a viscosity of 1,500 cps to 2,000 cps at
250.degree. C.
16. The process according to claim 7, wherein a voltage of 2,000 V
to 50,000 V is applied to the spray nozzle to carry out a melt
electrostatic spray deposition.
17. The process according to claim 6, wherein the particulate
polylactic acid resin has an average particle size of 1 .mu.m to
100 .mu.m.
18. (canceled)
19. (canceled)
20. (canceled)
Description
TECHNICAL FIELD
[0001] The present disclosure relates to a foamable resin
composition for a foam sheet, a foam sheet, a process for preparing
a particulate polylactic acid resin, and a process for preparing a
foam sheet.
BACKGROUND ART
[0002] Products in which a polylactic acid is used are produced
through multiple heat processes. It has been reported that a
polylactic acid is sensitive to heat, and, therefore, a hydrolysis
proceeds at a high temperature. Due to the property of the
polylactic acid, a hydrolysis caused by heat during a process for
preparing a polylactic acid product leads to a change of a
molecular weight, which affects the state of the end product
produced.
DISCLOSURE
Technical Problem
[0003] One embodiment of the present disclosure provides a foamable
resin composition for a foam sheet, which can produce a foam sheet
including a polylactic acid resin and having an improved
shelf-life.
[0004] Another embodiment of the present disclosure provides a
process for preparing a polylactic acid resin of microparticles,
included in the foamable resin composition.
[0005] Still another embodiment of the present disclosure provides
a process for preparing a foam sheet, using the foamable resin
composition for a foam sheet.
Technical Solution
[0006] In one embodiment of the present disclosure, a foamable
resin composition for a foam sheet comprising polylactic acid resin
particles, each of the particles having a particle size of about 1
.mu.m to about 100 .mu.m, is provided.
[0007] A foam sheet prepared by molding the composition may
comprise a polylactic acid resin having a weight average molecular
weight of about 100,000 to about 200,000.
[0008] The composition may be a suspension in which the polylactic
acid resin particles are dispersed in a liquid solvent.
[0009] In another embodiment of the present disclosure, a foam
sheet comprising polylactic acid resin particles, each of the
particles having a particle size of about 1 .mu.m to 100 .mu.m, is
provided.
[0010] The foam sheet may comprise a polylactic acid resin having a
weight average molecular weight of about 100,000 to about
200,000.
[0011] In still another embodiment of the present disclosure, a
process for preparing a particulate polylactic acid resin
comprises: introducing a polylactic acid resin and then forming a
molten polylactic acid spray solution; and spraying the molten
polylactic acid spray solution by a melt spray method and
simultaneously cooling the molten polylactic acid spray solution to
obtain a particulate polylactic acid.
[0012] The polylactic acid resin may be introduced into an
extruder, and then transferred to an spray nozzle and heated in the
spray nozzle to form the molten polylactic acid spray solution.
[0013] The polylactic acid resin n the form of pellet or powder may
be introduced into the extruder.
[0014] The molten polylactic acid spray solution may be introduced
into the spray nozzle together with an air and then discharged.
[0015] A temperature of the air that is introduced into the spray
nozzle may be of about 300.degree. C. to about 500.degree. C., a
pressure of the air that is injected into the spray nozzle may be
of about 100 psi to about 1,000 psi, an injection speed of the air
that is injected into the spray nozzle may be of about 10 m/s to
about 50 m/s.
[0016] A temperature of the spray nozzle may be of about
200.degree. C. to about 400.degree. C.
[0017] A pressure of the spray nozzle may be of about 10 psi to
about 1,000 psi.
[0018] A diameter of the spray nozzle may be of about 0.5 mm to
about 3.0 mm.
[0019] The molten polylactic acid spray solution may comprise at
least one additive selected from the group consisting of a
lubricant, a plasticizer, and a combination thereof.
[0020] The molten polylactic acid spray solution may have a
viscosity of about 1,500 cps to about 2,000 cps at 250.degree.
C.
[0021] A voltage of about 2,000 V to about 50,000 V may be applied
to the spray nozzle to carry out a melt electrostatic spray
deposition.
[0022] The particulate polylactic acid resin may have an average
particle size of about 1 .mu.m to about 100 .mu.m.
[0023] In still another embodiment of the present disclosure, a
process for preparing a foam sheet comprising a polylactic acid
foam layer, comprising: mixing a particulate polylactic acid resin
having an average particle size of 1 .mu.m to 100 .mu.m, a foam
resin, and an additive to form a foamable resin composition, and
then applying the foamable resin composition to form a layer; and
allowing the resultant layer to foam and consequently forming a
foam layer is provided.
[0024] The particulate polylactic acid resin is obtained by a melt
spray method.
[0025] The foam sheet prepared by the process may comprise a
polylactic acid resin having a weight average molecular weight of
about 100,000 to about 200,000.
Advantageous Effects
[0026] A foam sheet prepared by using the microparticulate
polylactic acid resin has excellent durability and surface property
and improved shelf-life.
DESCRIPTION OF DRAWINGS
[0027] FIG. 1 schematically shows a process flow diagram of a
process for preparing a foam sheet according to one embodiment of
the present disclosure; and
[0028] FIG. 2 schematically shows a process flow diagram of a
process for preparing a foam sheet.
BEST MODE
[0029] Hereinafter, exemplary embodiments of the present disclosure
will be described in detail. It should be understood, however, that
the drawings and detailed description thereto are not intended to
limit the present disclosure to the particular form disclosed, but
on the contrary, the intention is to cover all modifications,
equivalents, and alternatives falling within the spirit and scope
of the present disclosure as defined by the appended claims.
[0030] In one embodiment of the present disclosure, polylactic acid
resin particles having an average particle size of about 1 .mu.m to
about 100 .mu.m are provided.
[0031] The polylactic acid resin particles having the particle size
range may be prepared by a melt spray method. Further, more uniform
polylactic acid particles may be obtained by introducing an air
having a high temperature and a high pressure together to an spray
nozzle during performing the melt spray method. The melt spray
method may be carried out by a melt electrostatic spray deposition
(melt ESD) applying a voltage during performing the melt spray
method.
[0032] A process according to another embodiment of the present
disclosure for preparing polylactic acid resin particles having an
average particle size of about 1 .mu.m to about 100 .mu.m,
comprises: introducing a polylactic acid resin and then forming a
molten polylactic acid spray solution; and spraying the molten
polylactic acid spray solution by a melt spray method and
simultaneously cooling the molten polylactic acid spray solution to
obtain a particulate polylactic acid.
[0033] The process for preparing a particulate polylactic acid
resin has advantages to easily control the size of the polylactic
acid resin particles formed by applying the melt spray method and
to make a distribution of the particle size uniform. For example,
ploylactic acid resin particles having an average particle size of
about 1 .mu.m to about 100 .mu.m may be prepared by the process for
preparing a particulate polylactic acid resin.
[0034] To perform the melt spray method, firstly, a polylactic acid
in the form of pellet or powder is introduced into an extruder
equipped with an spray nozzle, and then the polylactic acid is
melted in the high temperature spray nozzle to form a molten
polylactic acid spray solution. Such molten polylactic acid spray
solution is sprayed in the form of a liquid droplet in micrometers.
In addition, such spraying is performed in a cooling chamber,
allowing the liquid droplet to be cooled to form microparticles of
the polylactic acid resin.
[0035] The melt spray method is optionally carried out by a melt
electrostatic spray deposition applying a voltage to the spray
nozzle.
[0036] The molten polylactic acid spray solution is introduced into
the spray nozzle together with an air and then discharged.
[0037] By controlling the temperature, pressure and velocity of the
air that is introduced into the spray nozzle, the size and shape of
a liquid droplet of the molten polylactic acid spray solution
discharged may be controlled, whereby the particle size of a
polylactic acid resin to be finally obtained may be controlled.
[0038] For example, a temperature of the air that is introduced
into the spray nozzle may be of about 300.degree. C. to about
500.degree. C., a pressure of the air may be of about 10 psi to
about 1,000 psi, and an injection speed of the air may be of about
10 m/s to about 50 m/s.
[0039] In the melt spray method, a viscosity of the melted
polylactic acid may be controlled to be sprayed as a liquid droplet
in micrometers.
[0040] To control the viscosity of the melted polylactic acid resin
may be achieved by a method, such as adjusting the temperature of
the spray nozzle, adding an additive, such as a lubricant, a
plasticizer, or the like, together with the polylactic acid resin,
to the extruder to be compounded, or introducing a gas such as
CO.sub.2 to the polylactic acid resin in the form of pellet, and
the like.
[0041] For example, a diameter of the spray nozzle may be of about
0.5 mm to about 3.0 mm.
[0042] In particular, a viscosity of the molten polylactic acid
spray solution may be of about 1,500 cps to about 2,000 cps at
about 250.degree. C. With forming a coating solution having the
above viscosity range, a microparticulate polylactic acid resin may
be formed.
[0043] Process conditions of the melt spray method are not
particularly limited, and the known process conditions, for
example, a pressure of the spray nozzle of about 100 psi to about
1,000 psi may be applied.
[0044] However, the melt spray method should be carried out at a
temperature range in which the polylactic acid melts. For example,
a temperature of the spray nozzle may be of about 200.degree. C. to
about 400.degree. C.
[0045] In addition, a diameter of the spray nozzle may be of about
0.5 mm to about 3.0 mm in order to form the microparticulate
polylactic acid resin as described above.
[0046] The melt spray method may be carried out, for example, by a
melt electrostatic spray deposition applying a voltage of about
2,000 V to about 50,000 V to the spray nozzle.
[0047] The microparticulate polylactic acid resin which may be
prepared by the process can be advantageously applied to a
preparation of a foam sheet.
[0048] In another embodiment of the present disclosure, a foam
sheet comprising polylactic acid resin particles, each of the
particles having a particle size of about 1 .mu.m to about 100
.mu.m, is provided. The foam sheet may be prepared by using the
polylactic acid resin particles having a small particle size in
micrometers, in accordance with a process for preparing a foam
sheet as mentioned below, and the thus prepared foam sheet
minimizes the number of heat processes to minimize the degradation
of the polylactic acid resin, allowing the maintenance of higher
molecular weight. In particular, the foam sheet may comprise a
polylactic acid resin having a weight average molecular weight of
about 100,000 to about 200,000.
[0049] FIG. 2 shows a process flow diagram of an exemplary process
for preparing a foam sheet. Generally, a foam sheet applied with a
polylactic acid resin has been produced through a variety of
processes. More specifically, a lubricant, an additive, a
stabilizer, or the like is firstly added to a polylactic acid resin
in the form of powder or pellet, followed by blending, kneading and
T-die extrusion, and then lamination with paper and foaming
process. In general, until a foam sheet is prepared by the
processes, approximately at least three or four heat processes are
performed.
[0050] However, a polylactic acid resin is known to be sensitive to
heat treatment since it is hydrolyzed at a high temperature. Due to
the property of the polylactic acid resin, the hydrolysis of the
foam sheet, applied with the polylactic acid resin, by heat during
a process affects the molecular weight of the polylactic acid resin
to result in the degradation of a product.
[0051] In still another embodiment of the present disclosure, a
process for preparing a foam sheet, capable of reducing the number
of heat processes by using a microparticulate polylactic acid
resin, is provided.
[0052] In one embodiment, a process for preparing a foam sheet
comprising a polylactic acid foam layer, comprising: mixing a
particulate polylactic acid resin having an average particle size
of about 1 .mu.m to about 100 .mu.m, a foam resin, and an additive
to form a foamable resin composition, and then applying the
foamable resin composition to form a layer; and allowing the
resultant layer to foam and consequently forming a foam layer is
provided.
[0053] The foamable resin composition allows the polylactic acid
resin to be mixed in a microparticle size to form a suspension.
Specifically, the foamable resin composition in the form of sol-gel
may foams to form a polylactic acid foam layer.
[0054] FIG. 1 shows a process flow diagram of a process for
preparing a foam sheet according to one embodiment of the present
disclosure. A powder of polylactic acid particles having a micro
size is firstly prepared by applying a melt spray method (FIG. 1,
MELT ESD step); a suspension is prepared by mixing a foamable resin
composition comprising the powder of polylactic acid particles
having a micro size (FIG. 1, MIXING (PREPARING SOL) step); a
coating layer is formed by coating the suspension on a substrate
(FIG. 1, SOL COATING step); and, subsequently, the coating layer
foams (FIG. 1, FOAMING step) to form a foam layer, whereby a foam
sheet may be prepared.
[0055] By the process for preparing a foam sheet, a foam sheet
comprising a polylactic acid foam layer comprising the above
polylactic acid resin particles having an average particle size of
about 1 .mu.m to about 100 .mu.m may be prepared.
[0056] The foam resin may be a material used in preparing a foam
layer of a foam sheet, such as PVC, polyurethane, and the like,
without being limited thereto.
[0057] In the foam layer formed as described above, the
microparticles of the polylactic acid resin are evenly dispersed.
Since the polylactic acid resin is evenly dispersed, the surface
property of the product, the foam sheet finally produced, may be
improved, whereby the durability of the foam sheet is enhanced.
[0058] Since the process for preparing a foam sheet may reduce the
number of heat processes, compared with the well-known processes
for preparing a foam sheet, the damage resulting from a hydrolysis
of a polylactic acid resin may be remarkably lowered, whereby the
loss of the molecular weight by the hydrolysis of the polylactic
acid resin may be inhibited. Therefore, the foam sheet prepared by
the above process unexpectedly improves the product degradation by
heat processes to result in an extended shelf-life.
[0059] In the foam sheet produced by the above process for
preparing a foam sheet, the molecular weight of the
microparticulate polylactic acid resin may be maintained without a
remarkable loss resulting from a hydrolysis. For example, the foam
sheet produced by the above process for preparing a foam sheet may
comprise a polylactic acid resin having a weight average molecular
weight of about 100,000 to about 200,000.
[0060] Particularly, the foam sheet produced by the above process
for preparing a foam sheet may comprise a polylactic acid resin
having a weight average molecular weight of about 100,000 or
more.
[0061] Hereinafter, the present disclosure will be explained in
more detail with reference to an example and a comparative example.
However, it should be understood that these examples are provided
for illustration only and are not to be in any way construed as
limiting the present disclosure.
EXAMPLES
Example 1
[0062] Using a polylactic acid resin in the form of pellet,
particles having an average particle size of 50 .mu.m were prepared
by a melt electrostatic spray deposition. On performing the melt
electrostatic spray deposition, a temperature of an spray nozzle
was 250.degree. C., a pressure of the spray nozzle was 500 psi, and
a diameter of the spray nozzle was 1 mm, a voltage of 20,000 V was
applied to the spray nozzle, and a viscosity of a molten polylactic
acid spray solution was 2,000 cps at 250.degree. C.
[0063] The resulting polylactic acid particles, and additives
including a plasticizer, a stabilizer, a lubricant and the like
were added and blended to prepare a polylactic acid
resin-containing sol. The resulting polylactic acid
resin-containing sol was subjected to a sol-gel coating on a
substrate, followed by drying (foaming) to obtain a foam sheet
sample having a thickness of about 0.5 mm.
Comparative Example 1
[0064] Additive including a plasticizer, a stabilizer, a lubricant
and the like was added to a polylactic acid resin in the form of
pellet as in Example 1 and mixed to prepare a polylactic acid
resin-containing mixture composition. The polylactic acid
resin-containing mixture composition was kneaded at 150.degree. C.
with a Banbury mixer, and the first and the second mixing were
conducted with two roll mill at 150.degree. C. The thus prepared
mixing materials were subjected to calendering process and foaming
process to obtain a foam sheet having a thickness of about 0.5
mm.
EVALUATION
Experiment 1: Polylactic Acid Molecular Weight Determination
[0065] With respect to the foam sheet samples prepared in Example 1
and Comparative Example 1, the weight average molecular weights
thereof were determined with the GPC (gel permeation
chromatography) (e2695, Waters), and shown in Table 1.
Experiment 2: Durability Evaluation
[0066] Each of the foam sheets prepared in Example 1 and
Comparative Example 1 was determined for its impact resistance
according to the ASTM D256 method, and results are shown in Table
1.
Experiment 3: Surface Property Evaluation
[0067] The surface property of each of the foam sheets prepared in
Example 1 and Comparative Example 1 were visually determined, and
shown in Table 1. The evaluation criteria are visual assessment and
the surface property was scored from 5 (excellent) to 1 (NG) using
a 5-point scale.
TABLE-US-00001 TABLE 1 Polylactic acid particles before Polylactic
acid preparation of Polylactic acid in foam sheet of foam sheet of
in foam sheet Comparative Items Example 1 of Example 1 Example 1
Weight average 150,000 120,000 80,000 molecular weight Impact
resistance -- 20 30 [kgf cm/cm] Surface Property -- Blocking: 5
Blocking: 4 Blushing: 4 Blushing: 3
* * * * *