Shape Memory PLA Composite - Innovation Takes Root
Using Biomass
ITR 2012
Highly functional PLA composites used for electronic products Masatoshi Iji, Dr. Eng. Yukihiro Kiuchi Green Innovation Research Laboratories NEC Corporation 1
Contents -Introduction -NEC’s bioplastics (PLA composites) 1)Kenaf-Reinforced PLA composite 2)Flame retardant PLA composite 3)Shape memory PLA composite 4)Heat conductive PLA composite 5)New nano-filler
-Conclusion 2
NEC’s Introduction Capital
¥397.2 billion (As of Mar. 31, 2011)
Consolidated Net Sales
¥3,115.4 billion (Fiscal year ended Mar. 31 2011)
Major Operations of the NEC Group
IT Services, Platform, Carrier Network, Social Infrastructure, Personal Solutions
Employees
NEC Corporation 23,935 (As of Mar. 31, 2011) NEC Corporation and Consolidated Subsidiaries 115,840 (As of Mar. 31, 2011)
Consolidated Subsidiaries
283 (As of Mar. 31, 2011)
3
Developing Original Bioplastics by NEC
Eco-Electronic Products Using bioplastics
Bioplastics
NEC R&D: Making concept of original bioplastics and developing their key technologies
Bioplastics
Material Producers
Users
Collaborating to finish practical products, mass-producing and supplying
= Kao, Unitika, etc
First step: NEC uses its original bioplastics in its eco-friendly electronic products Second step: Material producers supply the bioplastics to users 4
Merits and Subjects of Bioplastics - Bioplastics made of biomass aid reduction of petroleum resource exhaust and CO2 gas causing global warming - Bioplastics, especially Polylactic acid (PLA) have begun to be used in durable products in addition to table ware, sealing, and fiber. -Merit: Increase of environmental friendliness of products -Subject： Improvement for practical characteristics with keeping biomass content and safety
CO2 Air
Table ware Sealing Fiber
Fixation
Plants
Bioplastics (PLA, etc)
Starch
Durable Products Practical characteristic should be improved.
5
Recent Main News of Use of Bioplastics in Durable Products in Japan 2002: Fujitsu firstly started to use PLA in a part (IR mask) in personal computer. 2002: Sony used PLA in housing of “Walkman”. 2003: Toyota used PLA in cover of spear tire and floor mat. 2004: NEC used PLA/Kenaf composite in dummy cards in personal computer. 2005 : Fujitsu used flame-retarding PLA/PC composite in personal computer. 2006 : NEC and NTT DoCoMo used PLA/Kenaf composite in ECO-cellular phone. 2007: Mitubishi Motors used PBS/bamboo composite in board in car. 2008 : Fuji Xerox, Ricoh and Canon used PLA composites in copiers. NEC used PLA/Kenaf composite in lighting. 2010: NEC used flame-retardant PLA composite In PC. 2011 ↑ Projector
6
PLA’s Subjects for Use in Durable Products -Resource ： Starch, etc CH3
-Main Mass production: Nature Works / USA
O -CH --C －n
-PLA composite suppliers in Japan Kao, Unitika, Toray, Mitsubishi Resin, etc
PLA
O
(Polylactic acid)
-Technical Problems Insufficient characteristics for durable products Its heat resistance, strength, moldability （long molding time at high temp.) , flame retardancy should be improved.
Decrease of biomass content Previous technologies have been mainly adding large amounts (＞ 70%) of petroleum- based plastics to PLA to improve its characteristics.
Use of edible resource Fears of future food shortages are driving an effort to use plant resources that are not edible.
7
NEC’s Highly Functional PLA Composites for Electronics Creating high and new functions while keeping high environmental friendliness
CO2 Fixation Plant resource Starch
★High practical characteristics while keeping high biomass ratio Heat resistance
Flame retardancy
Adding aluminum hydroxide, etc Adding kenaf fiber
Poly lactic acid (PLA)
Cellular phone Lighting(2008） (2006）
★New functions
In future
Biomass >80%
Toughness
Biomass >75%
PC (2010)
New nano-filler
Heat conductivity
Shape memory
Including networks of carbon fiber (CF) Device
Cellulose, etc
Wearable products
Thermoreversible crosslinking of PLA
Heat
Housing
8 Thin and small type products
(1) Kenaf-Reinforced PLA Composite [ Accomplishment ]
CO2 Developing a highly heat-resistant PLA composite by the combination with natural kenaf fiber (Maintaining high biomass ratio :>80%)
Fixation
Fixation
Fiber
Biomass
PLA
（Corn,etc.）
[ Technical Points ]
Kenaf
CO2 fixation is 3 to 9 times higher than that of other plants.
Other additives
a) The fiber of Kenaf (efficiently fixates CO2) increases PLA’s heat resistance, and modulus.
PLA-Kenaf Composite
Elastic modulus: 1.7 times Heat resistance: 1.8 times
Kenaf ポリ乳酸
Fiber
b) The impact strength was improved by adjusting the fiber length and adding a biomass-based flexibilizer c) The moldability was improved by adding a special crystallization promoter
PLA/Kenaf composite
Kenaf plantation
Kenaf and PLA9 with kenaf fiber
Application of Kenaf-Reinforced PLA Composite -Collaborating with Unitika LTD, etc -Biomass-ratio in PLA composite : >80wt% 2004 Dummy card
2008
2006
Lighting
ECO-cellular phone (FOMA-N-701iECO)
Phone
NTT DoCoMo
10 Under planning 7
(2) Flame-Retardant PLA Composite [Accomplishment] -Developing a highly flame-retardant PLA composite without halogen flame retardant
Aluminum hydroxide
FR PLA composite PLA composite
[Technical Points] a) The PLA composite with aluminum hydroxide and a charring gent achieves high flame retardancy. b) Unique additives recover other practical characteristics.
Charring agent Safe additives
Self-extinguishing
・Achieving high biomass ratio >75%*, chemical safety, high flame retardancy, and good moldability (reducing molding time) -It has been used in casings of personal computer and projector (collaborating with Kao Corp.)
11
(*In organic elements)
Points of Flame- Retardant PLA Composite Previous flame-retardant PLA composite Petroleum based plastic Bioplastic (PLA) Flame retardant Flame retardant
Base resin : Petroleum plastic Adding PLA Biomass ratio ～30% in organic elements
Insufficient reduction of petroleum and CO2
NEC’s flame-retardant PLA composite Bioplastic (PLA)
Safe additives Aluminum Hydroxide
Base resin : PLA Adding safe additives Biomass ratio >75% in organic elements (Example composition: Inorganic element:40%、 PLA:45％,Petroleum:15%)
Great reduction of petroleum (>75%) 12 and CO2 (～50%)
Flame retardancy of PLA composite containing aluminum hydroxide and charring agent
Flaming time after ignition (s)
Flame retardancy by UL method
Self-extinguishing after ignition
Burning
200 150
V-1 or V-2
Adding charring agent
100 50
V-0 0
Aluminum hydroxide=Absorbing heat Charring agent=Forming foam layer
0
0 Aluminum hydroxide content
Charring agent decreasing amount of aluminum hydroxide Other specific additives Achieving good practical properties and high flame retardancy 13 without halogen (bromine） flame retardants
LCA of FR PLA Composite Life cycle assessment (LCA) of a part of PC CO2 generation (g) / one part : 55g
～500g Molding
- 50% Material production
Flame-retardant petroleum based plastic : PC/ABS
ＮＥＣ’s FR PLA composite 80 centigrade 90 seconds/ cycle
14
Characteristics of FR PLA Composite - Flame retardancy :
UL-V0 / 1.8-13mmt UL-V1 / 1.2-
1.7mmt - Spiral flow during molding: >130mm ( 200 oC, 942 kg/cm2 )
- Izod impact strength: >50J/m
The PLA composite can be applied to desk top- type PC and other applications. Distance between gates: 220mm Thickness: 2.5mm 15 Many bosses and slits
Characteristics data of FR PLA composites PLA Plant Ratio(%) CO2 Reduction Ratio (%) HDT(0C) /1.8MPa /0.45MPa Flexural Strength (MPa) Strain (%)
Izot Impact Strength （J/m)
Flame Retardancy (UL)
Collaborating with Kao
Flame retardant PLA composites
Petroleum based
PC/ABS
in development
100
＞75
～75
０
70
～50
～50
０
50
58 120
73
84
94 3
44 8.5
48 11
95 >10
26
54
72
150
NOT
1.8mmt V0
1.6mmt V0
1.6mmt V0
110 ＞300
80 ～40
70 30
60 20
Moldability* Molding Temp. (0C) Holding Time (Sec.) *2mmt test piece
16
Current application of FR PLA composite
PC
Projector
Casher Collaborating with Kao Corp. 17
(3) Shape Memory PLA Composite [ Accomplishment ]
Melt
Development of new biomass-based plastics performing shape memorybioplastic Development of a new intelligent and recycling (rewritable memory) (PLA) performing shapeshape memory and recycling
Recycling
~160oC PLA
[ Technical Points ] a) Thermo-reversible cross-linking of PLA provides it with good shape memory and enables it to be recycled (re-molded). b) Application of the plastic in electronics creates new products
Shape memory
~60oC
Thermo-reversible bonding
Free-style products (wearable), shapes of which are deformed by consumers 18
Shape Memory and Recycling
19
Free-style (Wearable) Mobile Products in Future Using Shape Memory PLA Composite
20
(4) Heat Conductive PLA Composite [ Accomplishment ] Creation of cross-linked carbon fiber in PLA achieves high heat diffusion
Improving heat-release issues caused by the latest and future small and thin sized electronic products (mobile phones, note-PCs, etc) [ Technical points ] Heat-conductive housing made from the PLA composite
Cross-linked carbon fiber in PLA Binder (Natural amide compound)
Electronic parts generating heat
Heat flow
Housing of PLA composite
PLA
Carbon fiber （～10％／5mm）
0.1mm
High heat-release in the plane direction of the housing by the cross-linked carbon fiber in PLA 21
Heat Diffusion of PLA/CF Composite
Max.temp
The densities (1.3-1.5) of the composites are less than 1/5 of stainless steel22
Heat Diffusion in Plane Direction of PLA/CF Composite Temperature change of the upper side (Infrared thermo-graph: after 20 sec.) Observed
Heater 70oC PLA/CF composite (CF 20%)
Stainless steel
Temperature/ oC
Temperature change of the reverse side 56 54 52 50 48 46 44 42 40 38 0
Measured
Stainless steel
～ ～
0
PLA/CF composite shows plane direction of heat diffusion, which decreases hot spots on casings of thin-type products
PLA/CF composite (CF 20%) 5
10
Time / minutes
Specimen plate (1mmt)
15
23
(5) Nano-Particle Filler Improving Toughness of PLA [ Accomplishment ]
Developing new nano-particle filler to increase toughness (tenacity） of PLA [ Technical points ]
Self-assembling nano-siloxane particle with three layers: high density core, middle elastomeric layer and outside affinity layer for PLA by using unique silicone with three units Nano-particle consisting of three functional layers
Silicone with three units OCH3 CH3O Sｉ
X
OCH3
Self-assembling
Affinity layer for PLA
OC3H7 Si O CH3
X: -C3H6-NCOH-O-
Elastomeric layer
O 8
O ４
High density cores
Coagulation and condensation
24
Size:～11nm
Formation of New Nano-Filler with Three Functional Layers by Silicone with Three Units Silicone compound with three units OC3H7
OCH3
High polarity CH3O
Third unit
Second unit
First unit Sｉ
X
OCH3
Forming core
Si CH3
O
O 8
Forming middle layer
Self-assembling
O
４
Forming outside layer
Outside layer with high affinity for PLA
In solvent Heating + Cat.
Middle elastomeric layer
Mixing with PLA High density cores
Coagulation
Formation of core and middle layer by condensation (cross-linking)
25
Structure of Nano Filler SEM-EDX
SEM
Intensity of C (a, u)
Analysis of Si and C in nano particle along cross section 120
C
100
C
80 60 40 20 0 0
5
20nm
50
5nm
40 30
Intensity of Si (a, u)
Size distribution Abundance / %
15
20
25
20
25
Distance /nm
Average size: about 11nm
12
Si
10 8 6 4 2 0 0
20
5
10
15
Distance /nm
10 0 10-1
10
1
10
102
Diameter / nm
103
104
High densities of Si in the center comparing with C shows the presence 26 of cores
Improvement of Tenacity of PLA by Adding New Nano-Filler Flexural test of PLA composite with new nano-filler (5wt%) 120
Strength /MPa
100
Adding nano filler with three layers
PLA
80 Plasticity
Rubber like low elasticity
60 40
Core rigidity
20 0 0
1
2
3
4
5
6
Elongation /% -The nano filler can increase elongation of PLA while keeping its strength because of the rigidity of core, rubber-like low elasticity of its middle phase and the plasticity of the outside phase. 27 -The moldability and heat resistance of PLA are almost maintained.
Conclusion - NEC aims to achieve practical characteristics while maintaining high biomass ratio and safety, and new functions to create additional values for PLA. - A heat resistant PLA/Kenaf composite was developed and used in a cellular phone and light . - A flame-retardant PLA composite was developed and used in PC (2010) and projector (2011). The moldability (time, temp.) has been greatly improved. - New functional PLA composites performing shape memory and heat conductivity have been fundamentally developed for the use in the latest and future mobile electronic products. - New nano filler with three layers has been fundamentally developed to greatly improve toughness (tenacity) of PLA. - Replacing biomass of bioplastics from edible ingredient to inedible one is next important subject.
28
Formation of reversibly cross-linked PLA composite and its dissociation O
Deals Alder Reaction
O
Heat
O
+
O
N
N
Cool
O
O Maleimide
Fran
Low ～ Middle temp.(≦100 OC)
High temp.(≧160 OC)
Multi functional alcohol + PLA O OR
O OR
O
O OR
+
RO O OR
O OR
N
N O
O
O O
R:
3
O O
mO
PLA 100 oC, 1 h
160 oC, 10 min
Reversibly cross-linked PLA composite29
Effect of Breaking CF of CF-PLA Composite in Mixing-Molding on Heat Diffusion 1mm
*Screw shape and mixing method were changed Hand mixing- Press moldScrew mixing- Injection mold Improved*
Heat diffusion
30
Reference ・Masatoshi Iji, Naoki Morishita and Hiroyuki Kai, ”Self-assembling Siloxane Nanoparticles with Three Phases That Increase Tenacity of Poly L-lactic Acid”, Polymer Journal, 43,101104(2011). ・Akinobu Nakamura, Masatoshi Iji,” “How Hybridization with Zinc Oxide Whiskers and Carbon Fibers Affects the Thermal Diffusivity and Mechanical Properties of Poly(L-lactic acid) Nanocomposites”, J. Mater. Sci. 46,1439-1445 (2011). ・Akinobu Nakamura, Masatoshi Iji,” Enhancement of Thermal Diffusivity of Poly(L-lactic Acid) Composites with Carbon Fibers”, J. Matter. Sci. 44, 4572-4576(2009). ・K. Inoue, M. Yamashiro, M. Iji, “Recyclable Shape-Memory Polymer: Poly(lactic acid) Crosslinked by a Thermoreversible Diels-Alder Reaction”, Journal of Applied Polymer Science, 112,2,876-885(2009). ・M. Yamashiro, K. Inoue, M. Iji, “Recyclable Shape-memory and Mechanical Strength of Poly(lactic acid) Compounds Cross-linked by Thermo-reversible Diels-Alder Reaction”, Polymer Journal, 40,657-662(2008). ・S.Serizawa, K. Inoue, M. Iji,” Kenaf-fiber-reinforced Poly(lactic acid) Used for Electronic Products”, Journal of Applied Polymer Science, 100,1,618-624(2006).
http://www.nec.co.jp/rd/en/innovative/bioplastics/top.html 31
Contact -NEC Corp Masatoshi Iji or Yukihiro Kiuchi E-mail: [email protected] [email protected] http://www.nec.co.jp/rd/en/innovative/bioplastics/top.html
-Kao Corp. ------ (Flame Retarding PLA composite) Norihiro Hayashi or Yuusaku Tsuchiya E-mail : [email protected] [email protected] -Unitika LTD. -----(Kenaf-reinforced PLA composite) Akinobu Ogami E-mail: [email protected] 32
ITR 2012
Highly functional PLA composites used for electronic products Masatoshi Iji, Dr. Eng. Yukihiro Kiuchi Green Innovation Research Laboratories NEC Corporation 1
Contents -Introduction -NEC’s bioplastics (PLA composites) 1)Kenaf-Reinforced PLA composite 2)Flame retardant PLA composite 3)Shape memory PLA composite 4)Heat conductive PLA composite 5)New nano-filler
-Conclusion 2
NEC’s Introduction Capital
¥397.2 billion (As of Mar. 31, 2011)
Consolidated Net Sales
¥3,115.4 billion (Fiscal year ended Mar. 31 2011)
Major Operations of the NEC Group
IT Services, Platform, Carrier Network, Social Infrastructure, Personal Solutions
Employees
NEC Corporation 23,935 (As of Mar. 31, 2011) NEC Corporation and Consolidated Subsidiaries 115,840 (As of Mar. 31, 2011)
Consolidated Subsidiaries
283 (As of Mar. 31, 2011)
3
Developing Original Bioplastics by NEC
Eco-Electronic Products Using bioplastics
Bioplastics
NEC R&D: Making concept of original bioplastics and developing their key technologies
Bioplastics
Material Producers
Users
Collaborating to finish practical products, mass-producing and supplying
= Kao, Unitika, etc
First step: NEC uses its original bioplastics in its eco-friendly electronic products Second step: Material producers supply the bioplastics to users 4
Merits and Subjects of Bioplastics - Bioplastics made of biomass aid reduction of petroleum resource exhaust and CO2 gas causing global warming - Bioplastics, especially Polylactic acid (PLA) have begun to be used in durable products in addition to table ware, sealing, and fiber. -Merit: Increase of environmental friendliness of products -Subject： Improvement for practical characteristics with keeping biomass content and safety
CO2 Air
Table ware Sealing Fiber
Fixation
Plants
Bioplastics (PLA, etc)
Starch
Durable Products Practical characteristic should be improved.
5
Recent Main News of Use of Bioplastics in Durable Products in Japan 2002: Fujitsu firstly started to use PLA in a part (IR mask) in personal computer. 2002: Sony used PLA in housing of “Walkman”. 2003: Toyota used PLA in cover of spear tire and floor mat. 2004: NEC used PLA/Kenaf composite in dummy cards in personal computer. 2005 : Fujitsu used flame-retarding PLA/PC composite in personal computer. 2006 : NEC and NTT DoCoMo used PLA/Kenaf composite in ECO-cellular phone. 2007: Mitubishi Motors used PBS/bamboo composite in board in car. 2008 : Fuji Xerox, Ricoh and Canon used PLA composites in copiers. NEC used PLA/Kenaf composite in lighting. 2010: NEC used flame-retardant PLA composite In PC. 2011 ↑ Projector
6
PLA’s Subjects for Use in Durable Products -Resource ： Starch, etc CH3
-Main Mass production: Nature Works / USA
O -CH --C －n
-PLA composite suppliers in Japan Kao, Unitika, Toray, Mitsubishi Resin, etc
PLA
O
(Polylactic acid)
-Technical Problems Insufficient characteristics for durable products Its heat resistance, strength, moldability （long molding time at high temp.) , flame retardancy should be improved.
Decrease of biomass content Previous technologies have been mainly adding large amounts (＞ 70%) of petroleum- based plastics to PLA to improve its characteristics.
Use of edible resource Fears of future food shortages are driving an effort to use plant resources that are not edible.
7
NEC’s Highly Functional PLA Composites for Electronics Creating high and new functions while keeping high environmental friendliness
CO2 Fixation Plant resource Starch
★High practical characteristics while keeping high biomass ratio Heat resistance
Flame retardancy
Adding aluminum hydroxide, etc Adding kenaf fiber
Poly lactic acid (PLA)
Cellular phone Lighting(2008） (2006）
★New functions
In future
Biomass >80%
Toughness
Biomass >75%
PC (2010)
New nano-filler
Heat conductivity
Shape memory
Including networks of carbon fiber (CF) Device
Cellulose, etc
Wearable products
Thermoreversible crosslinking of PLA
Heat
Housing
8 Thin and small type products
(1) Kenaf-Reinforced PLA Composite [ Accomplishment ]
CO2 Developing a highly heat-resistant PLA composite by the combination with natural kenaf fiber (Maintaining high biomass ratio :>80%)
Fixation
Fixation
Fiber
Biomass
PLA
（Corn,etc.）
[ Technical Points ]
Kenaf
CO2 fixation is 3 to 9 times higher than that of other plants.
Other additives
a) The fiber of Kenaf (efficiently fixates CO2) increases PLA’s heat resistance, and modulus.
PLA-Kenaf Composite
Elastic modulus: 1.7 times Heat resistance: 1.8 times
Kenaf ポリ乳酸
Fiber
b) The impact strength was improved by adjusting the fiber length and adding a biomass-based flexibilizer c) The moldability was improved by adding a special crystallization promoter
PLA/Kenaf composite
Kenaf plantation
Kenaf and PLA9 with kenaf fiber
Application of Kenaf-Reinforced PLA Composite -Collaborating with Unitika LTD, etc -Biomass-ratio in PLA composite : >80wt% 2004 Dummy card
2008
2006
Lighting
ECO-cellular phone (FOMA-N-701iECO)
Phone
NTT DoCoMo
10 Under planning 7
(2) Flame-Retardant PLA Composite [Accomplishment] -Developing a highly flame-retardant PLA composite without halogen flame retardant
Aluminum hydroxide
FR PLA composite PLA composite
[Technical Points] a) The PLA composite with aluminum hydroxide and a charring gent achieves high flame retardancy. b) Unique additives recover other practical characteristics.
Charring agent Safe additives
Self-extinguishing
・Achieving high biomass ratio >75%*, chemical safety, high flame retardancy, and good moldability (reducing molding time) -It has been used in casings of personal computer and projector (collaborating with Kao Corp.)
11
(*In organic elements)
Points of Flame- Retardant PLA Composite Previous flame-retardant PLA composite Petroleum based plastic Bioplastic (PLA) Flame retardant Flame retardant
Base resin : Petroleum plastic Adding PLA Biomass ratio ～30% in organic elements
Insufficient reduction of petroleum and CO2
NEC’s flame-retardant PLA composite Bioplastic (PLA)
Safe additives Aluminum Hydroxide
Base resin : PLA Adding safe additives Biomass ratio >75% in organic elements (Example composition: Inorganic element:40%、 PLA:45％,Petroleum:15%)
Great reduction of petroleum (>75%) 12 and CO2 (～50%)
Flame retardancy of PLA composite containing aluminum hydroxide and charring agent
Flaming time after ignition (s)
Flame retardancy by UL method
Self-extinguishing after ignition
Burning
200 150
V-1 or V-2
Adding charring agent
100 50
V-0 0
Aluminum hydroxide=Absorbing heat Charring agent=Forming foam layer
0
0 Aluminum hydroxide content
Charring agent decreasing amount of aluminum hydroxide Other specific additives Achieving good practical properties and high flame retardancy 13 without halogen (bromine） flame retardants
LCA of FR PLA Composite Life cycle assessment (LCA) of a part of PC CO2 generation (g) / one part : 55g
～500g Molding
- 50% Material production
Flame-retardant petroleum based plastic : PC/ABS
ＮＥＣ’s FR PLA composite 80 centigrade 90 seconds/ cycle
14
Characteristics of FR PLA Composite - Flame retardancy :
UL-V0 / 1.8-13mmt UL-V1 / 1.2-
1.7mmt - Spiral flow during molding: >130mm ( 200 oC, 942 kg/cm2 )
- Izod impact strength: >50J/m
The PLA composite can be applied to desk top- type PC and other applications. Distance between gates: 220mm Thickness: 2.5mm 15 Many bosses and slits
Characteristics data of FR PLA composites PLA Plant Ratio(%) CO2 Reduction Ratio (%) HDT(0C) /1.8MPa /0.45MPa Flexural Strength (MPa) Strain (%)
Izot Impact Strength （J/m)
Flame Retardancy (UL)
Collaborating with Kao
Flame retardant PLA composites
Petroleum based
PC/ABS
in development
100
＞75
～75
０
70
～50
～50
０
50
58 120
73
84
94 3
44 8.5
48 11
95 >10
26
54
72
150
NOT
1.8mmt V0
1.6mmt V0
1.6mmt V0
110 ＞300
80 ～40
70 30
60 20
Moldability* Molding Temp. (0C) Holding Time (Sec.) *2mmt test piece
16
Current application of FR PLA composite
PC
Projector
Casher Collaborating with Kao Corp. 17
(3) Shape Memory PLA Composite [ Accomplishment ]
Melt
Development of new biomass-based plastics performing shape memorybioplastic Development of a new intelligent and recycling (rewritable memory) (PLA) performing shapeshape memory and recycling
Recycling
~160oC PLA
[ Technical Points ] a) Thermo-reversible cross-linking of PLA provides it with good shape memory and enables it to be recycled (re-molded). b) Application of the plastic in electronics creates new products
Shape memory
~60oC
Thermo-reversible bonding
Free-style products (wearable), shapes of which are deformed by consumers 18
Shape Memory and Recycling
19
Free-style (Wearable) Mobile Products in Future Using Shape Memory PLA Composite
20
(4) Heat Conductive PLA Composite [ Accomplishment ] Creation of cross-linked carbon fiber in PLA achieves high heat diffusion
Improving heat-release issues caused by the latest and future small and thin sized electronic products (mobile phones, note-PCs, etc) [ Technical points ] Heat-conductive housing made from the PLA composite
Cross-linked carbon fiber in PLA Binder (Natural amide compound)
Electronic parts generating heat
Heat flow
Housing of PLA composite
PLA
Carbon fiber （～10％／5mm）
0.1mm
High heat-release in the plane direction of the housing by the cross-linked carbon fiber in PLA 21
Heat Diffusion of PLA/CF Composite
Max.temp
The densities (1.3-1.5) of the composites are less than 1/5 of stainless steel22
Heat Diffusion in Plane Direction of PLA/CF Composite Temperature change of the upper side (Infrared thermo-graph: after 20 sec.) Observed
Heater 70oC PLA/CF composite (CF 20%)
Stainless steel
Temperature/ oC
Temperature change of the reverse side 56 54 52 50 48 46 44 42 40 38 0
Measured
Stainless steel
～ ～
0
PLA/CF composite shows plane direction of heat diffusion, which decreases hot spots on casings of thin-type products
PLA/CF composite (CF 20%) 5
10
Time / minutes
Specimen plate (1mmt)
15
23
(5) Nano-Particle Filler Improving Toughness of PLA [ Accomplishment ]
Developing new nano-particle filler to increase toughness (tenacity） of PLA [ Technical points ]
Self-assembling nano-siloxane particle with three layers: high density core, middle elastomeric layer and outside affinity layer for PLA by using unique silicone with three units Nano-particle consisting of three functional layers
Silicone with three units OCH3 CH3O Sｉ
X
OCH3
Self-assembling
Affinity layer for PLA
OC3H7 Si O CH3
X: -C3H6-NCOH-O-
Elastomeric layer
O 8
O ４
High density cores
Coagulation and condensation
24
Size:～11nm
Formation of New Nano-Filler with Three Functional Layers by Silicone with Three Units Silicone compound with three units OC3H7
OCH3
High polarity CH3O
Third unit
Second unit
First unit Sｉ
X
OCH3
Forming core
Si CH3
O
O 8
Forming middle layer
Self-assembling
O
４
Forming outside layer
Outside layer with high affinity for PLA
In solvent Heating + Cat.
Middle elastomeric layer
Mixing with PLA High density cores
Coagulation
Formation of core and middle layer by condensation (cross-linking)
25
Structure of Nano Filler SEM-EDX
SEM
Intensity of C (a, u)
Analysis of Si and C in nano particle along cross section 120
C
100
C
80 60 40 20 0 0
5
20nm
50
5nm
40 30
Intensity of Si (a, u)
Size distribution Abundance / %
15
20
25
20
25
Distance /nm
Average size: about 11nm
12
Si
10 8 6 4 2 0 0
20
5
10
15
Distance /nm
10 0 10-1
10
1
10
102
Diameter / nm
103
104
High densities of Si in the center comparing with C shows the presence 26 of cores
Improvement of Tenacity of PLA by Adding New Nano-Filler Flexural test of PLA composite with new nano-filler (5wt%) 120
Strength /MPa
100
Adding nano filler with three layers
PLA
80 Plasticity
Rubber like low elasticity
60 40
Core rigidity
20 0 0
1
2
3
4
5
6
Elongation /% -The nano filler can increase elongation of PLA while keeping its strength because of the rigidity of core, rubber-like low elasticity of its middle phase and the plasticity of the outside phase. 27 -The moldability and heat resistance of PLA are almost maintained.
Conclusion - NEC aims to achieve practical characteristics while maintaining high biomass ratio and safety, and new functions to create additional values for PLA. - A heat resistant PLA/Kenaf composite was developed and used in a cellular phone and light . - A flame-retardant PLA composite was developed and used in PC (2010) and projector (2011). The moldability (time, temp.) has been greatly improved. - New functional PLA composites performing shape memory and heat conductivity have been fundamentally developed for the use in the latest and future mobile electronic products. - New nano filler with three layers has been fundamentally developed to greatly improve toughness (tenacity) of PLA. - Replacing biomass of bioplastics from edible ingredient to inedible one is next important subject.
28
Formation of reversibly cross-linked PLA composite and its dissociation O
Deals Alder Reaction
O
Heat
O
+
O
N
N
Cool
O
O Maleimide
Fran
Low ～ Middle temp.(≦100 OC)
High temp.(≧160 OC)
Multi functional alcohol + PLA O OR
O OR
O
O OR
+
RO O OR
O OR
N
N O
O
O O
R:
3
O O
mO
PLA 100 oC, 1 h
160 oC, 10 min
Reversibly cross-linked PLA composite29
Effect of Breaking CF of CF-PLA Composite in Mixing-Molding on Heat Diffusion 1mm
*Screw shape and mixing method were changed Hand mixing- Press moldScrew mixing- Injection mold Improved*
Heat diffusion
30
Reference ・Masatoshi Iji, Naoki Morishita and Hiroyuki Kai, ”Self-assembling Siloxane Nanoparticles with Three Phases That Increase Tenacity of Poly L-lactic Acid”, Polymer Journal, 43,101104(2011). ・Akinobu Nakamura, Masatoshi Iji,” “How Hybridization with Zinc Oxide Whiskers and Carbon Fibers Affects the Thermal Diffusivity and Mechanical Properties of Poly(L-lactic acid) Nanocomposites”, J. Mater. Sci. 46,1439-1445 (2011). ・Akinobu Nakamura, Masatoshi Iji,” Enhancement of Thermal Diffusivity of Poly(L-lactic Acid) Composites with Carbon Fibers”, J. Matter. Sci. 44, 4572-4576(2009). ・K. Inoue, M. Yamashiro, M. Iji, “Recyclable Shape-Memory Polymer: Poly(lactic acid) Crosslinked by a Thermoreversible Diels-Alder Reaction”, Journal of Applied Polymer Science, 112,2,876-885(2009). ・M. Yamashiro, K. Inoue, M. Iji, “Recyclable Shape-memory and Mechanical Strength of Poly(lactic acid) Compounds Cross-linked by Thermo-reversible Diels-Alder Reaction”, Polymer Journal, 40,657-662(2008). ・S.Serizawa, K. Inoue, M. Iji,” Kenaf-fiber-reinforced Poly(lactic acid) Used for Electronic Products”, Journal of Applied Polymer Science, 100,1,618-624(2006).
http://www.nec.co.jp/rd/en/innovative/bioplastics/top.html 31
Contact -NEC Corp Masatoshi Iji or Yukihiro Kiuchi E-mail: [email protected] [email protected] http://www.nec.co.jp/rd/en/innovative/bioplastics/top.html
-Kao Corp. ------ (Flame Retarding PLA composite) Norihiro Hayashi or Yuusaku Tsuchiya E-mail : [email protected] [email protected] -Unitika LTD. -----(Kenaf-reinforced PLA composite) Akinobu Ogami E-mail: [email protected] 32
