WO1992001737A1 - Degradable foam materials - Google Patents

Degradable foam materials Download PDF

Info

Publication number
WO1992001737A1
WO1992001737A1 PCT/US1991/004241 US9104241W WO9201737A1 WO 1992001737 A1 WO1992001737 A1 WO 1992001737A1 US 9104241 W US9104241 W US 9104241W WO 9201737 A1 WO9201737 A1 WO 9201737A1
Authority
WO
WIPO (PCT)
Prior art keywords
product
blowing agent
units
foam
hfc
Prior art date
Application number
PCT/US1991/004241
Other languages
French (fr)
Inventor
Howard Sims Hammel
Robert Oliver York
Original Assignee
E.I. Du Pont De Nemours And Company
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by E.I. Du Pont De Nemours And Company filed Critical E.I. Du Pont De Nemours And Company
Priority to JP91511016A priority Critical patent/JPH05508669A/en
Publication of WO1992001737A1 publication Critical patent/WO1992001737A1/en

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/04—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent
    • C08J9/12—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a physical blowing agent
    • C08J9/14—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a physical blowing agent organic
    • C08J9/143—Halogen containing compounds
    • C08J9/144—Halogen containing compounds containing carbon, halogen and hydrogen only
    • C08J9/146—Halogen containing compounds containing carbon, halogen and hydrogen only only fluorine as halogen atoms
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2367/00—Characterised by the use of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Derivatives of such polymers
    • C08J2367/04—Polyesters derived from hydroxy carboxylic acids, e.g. lactones
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S521/00—Synthetic resins or natural rubbers -- part of the class 520 series
    • Y10S521/916—Cellular product having enhanced degradability

Definitions

  • This invention relates to foam materials, particularly for food service and food packaging applications.
  • the materials of this invention are degradable, both biodegradable and hydrolyzable. Furthermore., they contain no ozone-depleting chemicals nor chemicals that have significant photochemical reactivity. Also, they have little global warming potential compared to chlorofluorocarbons (CFCs) . Thus, this invention provides readily degradable foam packaging materials with minimal environmental impact.
  • polystyrene is not degradable, either in landfills or as roadside litter. Thus, unless collected and recycled, polystyrene foam products have an unlimited landfill and litter life.
  • CFC blowing agents trapped in the foam products eventually escape to the stratosphere where the chlorine enters an ozone-depletion cycle.
  • HC blowing agents, upon release from the foam are photochemically reactive and thus promote smog formation.
  • the foam packaging products of the present invention are foamed, degradable thermoplastic polymeric resin containing at least one hydroxy acid unit selected from the group consisting of: (1) (0(CR 2 R )nCO)p (2) (OCR1R2COOCR1R2CO) q
  • n is a whole number 2, 4 & 5, the total of p, q, r, s and t being 350 to about 5,000
  • Ri or R 2 which can be the same or different, is hydrogen, hydrocarbyl containing 1 to 12 carbon atoms, or substituted hydrocarbyl containing 1 to 12 carbon atoms.
  • the PHA comprises at least 50% of units of formula (1) .
  • the ratio p/q/r/s/t must be adjusted to impart crystallinity level and crystallization rates appropriate to oriented film production, as known in the art; containing a blowing agent of the formula
  • the products of the present invention are a degradable resin foamed by an environmentally benign hydrofluorocarbon (HFC) blowing agent.
  • HFC hydrofluorocarbon
  • the present invention is the use of HFCs of the formula (6) as a foam blowing agent for resins -of units of formulae (l)-(5) to produce highly useful, environmentally superior foam products.
  • Preferred polymers are those of formula (l) for which R is either hydrogen or the methyl group, in which case the polymers are known as polyglycolide or polylactide, respectively.
  • the polymers may be synthesized by polymerization directly from the acid precursors, or by the polymerization of the cyclic monomeric or dimeric (depending on the acid type) lactone. Polymerization from the cyclic lactone is preferred for producing high molecular weight polymers because equilibrium reactions with the intermediate, cyclic dimer and low molecular weight species place practical limits on the molecular weight of polymers produced directly from the acid.
  • the polymers of this invention have molecular weights from about 50,000 to about 600,000; and preferably from about 100,000 to about 450,000. High molecular weight is required to provide sufficient viscosity and strength to enable the polymer to form a sustainable foam. If the molecular weight is too high, excessive degradation occurs at the temperatures required to melt process the composi ⁇ tions.
  • the polymer compositions will normally contain some unreacted monomers and low molecular weight oligo ers. To avoid extrusion and foaming problems, it is desirable to keep low molecular weight, under 450, units in the polymer composition to less than about 7-1/2.
  • preferred polymer compositions are those having a major component of 50-97%, and most preferably from about 85 to 96 mol % of the L enantiomer of lactic acid corresponding to unit (2) above, where Ri is the methyl group, R 2 is the hydrogen atom.
  • the minor component of these preferred compositions can be any of the other units (1) to (5) above, with the proviso that if additional lactic acid units are utilized, they be of the D enantiomeric configuration.
  • degradation as used here with respect to the polylactate polymers means that the polylactate portion of the degradable material is biodegradable and, more importantly, degradable by hydrolysis.
  • the degradation rate is consistent with its intended usage, i.e., the product does not significantly degrade in normal storage and usage, but will degrade significantly in a reasonable time after discarding.
  • hydrolysis degradation is dependent on the degree of crystallinity of the polymer; the higher crystallinity polymers degrade more slowly.
  • slightly acidic or basic conditions may be used advantageously. By hydrolysis degradation, monomer units can be recovered if desired for reconversion to useful polylactate polymers or can be discarded as an environmentally benign waste material.
  • Acceptable blowing agents must have the following properties: environmental acceptability - low toxicity - appropriate volatility adequate solubility low reactivity acceptable diffusion rate relatively low molecular weight.
  • Environmental acceptability means that the blowing agent, when released from the foam product, will have no potential for stratospheric ozone depletion. In this regard, blowing agents containing chlorine atoms are unacceptable.
  • the blowing agent when released, must have a minimal infrared energy absorbability and appropriate atmospheric lifetime so that it will not have significant global warming potential, and also have negligible photochemical reactivity so as not to promote smog formation.
  • Low toxicity of the blowing agent is required to protect employees during foam manufacture. Also, it must not be toxic to uses of the foam products, which is of particular importance in food service and food packaging applications.
  • the blowing agent must also have appropriate volatility for use with the thermoplastic resins of the present invention. Such blowing agents must provide the solution pressure required to expand and foam the viscous polymeric resin.
  • the blowing agent must have adequate solubility, which means that the blowing agent is readily contained in the molten polymer when present in the concentration required for the needed degree of foaming. If the blowing agent separates from the polymeric resin before expansion of the blowing agent, gas pockets or non-uniform foam density can be caused.
  • the blowing agent must have low reactivity, which means that it will not react with the resin or decompose under the typical temperatures and pressures conventionally used in thermoplastic resin foam production. Similarly, the blowing agent must be nonreactive under normal use so as to prevent product degradation.
  • An acceptable diffusion rate is necessary for the blowing agents in the foams of the present invention.
  • a very slow diffusion rate is preferred so that the thermoforming of foamed sheet into shaped objects such as hamburger containers, plates, etc. is easily achieved.
  • a relatively low molecular weight blowing agent is desirable. Molecular weight determines the pounds of blowing agent needed to produce a given volume of gas. Thus, use bf a low molecular weight blowing agent minimizes the blowing agent cost per unit of production.
  • HFC blowing agents selected from those represented by formula (6) are ideally suited, with respect to the aforementioned properties, when used to make foam products with the polymeric resins of the units of formulae (l)-(5).
  • Suitable HFC blowing agents of formula (6) used with a specific polymeric resin of the units of formulae (l)-(5) can be readily determined by conventional techniques.
  • HFC-152a CH 3 ⁇ CHF 2 HFC-227
  • EA CF3-CHF-CF3 HFC-356
  • MFF CF 3 -CH 2 -CH -CF 3 HCC-365
  • the preferred HFCs are those containing one and two carbon atoms.
  • the foam products of the present invention have a unique combination of properties making them environmentally acceptable both with respect to the atmosphere and also for disposal. Concerning disposal, they can be landfilled whereupon they will biodegrade and/or hydrolyze to harmless degradation products, or they can be recycled by hydrolysis, preferably under slightly acidic or basic conditions, to form monomeric units that can be used in the production of polymer.
  • the foam products of the present invention can be made by conventional techniques.
  • the polymeric resin with the blowing agent therein can be pressure extruded at an appropriate temperature below the degradation or reaction temperature of the resin and the blowing agent.
  • the foamed product can be in the form of a sheet or a shaped article such as hamburger containers, trays, plates, boxes and the like. These products are particularly useful in food packaging and food service containers because of the combined properties of low toxicity and environmental acceptability.
  • Typical nucleants such as calcium silicate talc; processing aids such as mineral oils; extrusion aids such as dioctylphthalate (DOP) ; and color concentrates.
  • concentrations of the additives are generally independent of the amount of blowing agent. HFC manufacture is known in the art. See
  • the temperature of the material in the 4-1/2" extruder is maintained at 400-'F, and the pressure at 2500 lbs./sq. in. gauge. Prior to exiting the 6" extruder the temperature is dropped low enough to prevent cell collapse upon discharge from the extruder.
  • the HFC comes out of solution in the polymer, forming an oriented degrad ⁇ able thermoplastic foam product.
  • This product is rigid foam sheet 44 in. wide and 100 mils thick, having a density of 6 lbs. per cubic ft.
  • the sheet foam is then fed through a thermoformer where it is stamped into 12 in. circular plates.
  • sheets ranging from 50-100 mils thick are prepared and thermoformed into hinged food service containers.
  • the remaining PLA composition is D polylactic acid isomer plus less than 7% low molecular weight lactide and oligomer.

Abstract

Poly-hydroxy acid resin products foamed with hydrofluorocarbons (HFCs), which products are degradable and cause minimal environmental impact when discarded.

Description

TJTLE DEGRADABLE FOAM MATERIALS
BACKGROUND OF THE INVENTION
This invention relates to foam materials, particularly for food service and food packaging applications. The materials of this invention are degradable, both biodegradable and hydrolyzable. Furthermore., they contain no ozone-depleting chemicals nor chemicals that have significant photochemical reactivity. Also, they have little global warming potential compared to chlorofluorocarbons (CFCs) . Thus, this invention provides readily degradable foam packaging materials with minimal environmental impact.
BACKGROUND OF THE INVENTION At the present time, the most commonly used food service and food packaging materials are foamed polystyrene, usually foamed with chlorofluorocarbon (CFC) or hydrocarbon (HC) blowing agents. These products pose serious environmental problems.
First, polystyrene is not degradable, either in landfills or as roadside litter. Thus, unless collected and recycled, polystyrene foam products have an unlimited landfill and litter life.
Second, CFC blowing agents trapped in the foam products eventually escape to the stratosphere where the chlorine enters an ozone-depletion cycle. Third, HC blowing agents, upon release from the foam are photochemically reactive and thus promote smog formation.
Thus, there is a need for a foam of a degradable resin foamed by a blowing agent that does not enter into chemical reactions that cause environmental damage.
SUMMARY OF THE INVENTION The foam packaging products of the present invention are foamed, degradable thermoplastic polymeric resin containing at least one hydroxy acid unit selected from the group consisting of: (1) (0(CR2R )nCO)p (2) (OCR1R2COOCR1R2CO)q
(3) (OCRιR2CRι 2θCRιR2CO)r
(4) (OCRιR2CFιR2θCRιR2CRιR2CO)Hs
Figure imgf000004_0001
wherein n is a whole number 2, 4 & 5, the total of p, q, r, s and t being 350 to about 5,000, and Ri or R2, which can be the same or different, is hydrogen, hydrocarbyl containing 1 to 12 carbon atoms, or substituted hydrocarbyl containing 1 to 12 carbon atoms. Preferably the PHA comprises at least 50% of units of formula (1) . The ratio p/q/r/s/t must be adjusted to impart crystallinity level and crystallization rates appropriate to oriented film production, as known in the art; containing a blowing agent of the formula
Figure imgf000004_0002
wherein all A's are independently hydrogen or fluorine, and n = 1-4. Thus, the products of the present invention are a degradable resin foamed by an environmentally benign hydrofluorocarbon (HFC) blowing agent. In its simplest concept, the present invention is the use of HFCs of the formula (6) as a foam blowing agent for resins -of units of formulae (l)-(5) to produce highly useful, environmentally superior foam products. Preferred polymers are those of formula (l) for which R is either hydrogen or the methyl group, in which case the polymers are known as polyglycolide or polylactide, respectively. The polymers may be synthesized by polymerization directly from the acid precursors, or by the polymerization of the cyclic monomeric or dimeric (depending on the acid type) lactone. Polymerization from the cyclic lactone is preferred for producing high molecular weight polymers because equilibrium reactions with the intermediate, cyclic dimer and low molecular weight species place practical limits on the molecular weight of polymers produced directly from the acid. The polymers of this invention have molecular weights from about 50,000 to about 600,000; and preferably from about 100,000 to about 450,000. High molecular weight is required to provide sufficient viscosity and strength to enable the polymer to form a sustainable foam. If the molecular weight is too high, excessive degradation occurs at the temperatures required to melt process the composi¬ tions.
The polymer compositions will normally contain some unreacted monomers and low molecular weight oligo ers. To avoid extrusion and foaming problems, it is desirable to keep low molecular weight, under 450, units in the polymer composition to less than about 7-1/2. Also, preferred polymer compositions are those having a major component of 50-97%, and most preferably from about 85 to 96 mol % of the L enantiomer of lactic acid corresponding to unit (2) above, where Ri is the methyl group, R2 is the hydrogen atom. The minor component of these preferred compositions can be any of the other units (1) to (5) above, with the proviso that if additional lactic acid units are utilized, they be of the D enantiomeric configuration.
The term "degradable" as used here with respect to the polylactate polymers means that the polylactate portion of the degradable material is biodegradable and, more importantly, degradable by hydrolysis. The degradation rate is consistent with its intended usage, i.e., the product does not significantly degrade in normal storage and usage, but will degrade significantly in a reasonable time after discarding. As is known in the art, hydrolysis degradation is dependent on the degree of crystallinity of the polymer; the higher crystallinity polymers degrade more slowly. For hydrolysis degradation, slightly acidic or basic conditions may be used advantageously. By hydrolysis degradation, monomer units can be recovered if desired for reconversion to useful polylactate polymers or can be discarded as an environmentally benign waste material.
Acceptable blowing agents must have the following properties: environmental acceptability - low toxicity - appropriate volatility adequate solubility low reactivity acceptable diffusion rate relatively low molecular weight. Environmental acceptability means that the blowing agent, when released from the foam product, will have no potential for stratospheric ozone depletion. In this regard, blowing agents containing chlorine atoms are unacceptable. Also, when released, the blowing agent must have a minimal infrared energy absorbability and appropriate atmospheric lifetime so that it will not have significant global warming potential, and also have negligible photochemical reactivity so as not to promote smog formation. Low toxicity of the blowing agent is required to protect employees during foam manufacture. Also, it must not be toxic to uses of the foam products, which is of particular importance in food service and food packaging applications.
The blowing agent must also have appropriate volatility for use with the thermoplastic resins of the present invention. Such blowing agents must provide the solution pressure required to expand and foam the viscous polymeric resin.
The blowing agent must have adequate solubility, which means that the blowing agent is readily contained in the molten polymer when present in the concentration required for the needed degree of foaming. If the blowing agent separates from the polymeric resin before expansion of the blowing agent, gas pockets or non-uniform foam density can be caused.
The blowing agent must have low reactivity, which means that it will not react with the resin or decompose under the typical temperatures and pressures conventionally used in thermoplastic resin foam production. Similarly, the blowing agent must be nonreactive under normal use so as to prevent product degradation.
An acceptable diffusion rate is necessary for the blowing agents in the foams of the present invention. A very slow diffusion rate is preferred so that the thermoforming of foamed sheet into shaped objects such as hamburger containers, plates, etc. is easily achieved.
A relatively low molecular weight blowing agent is desirable. Molecular weight determines the pounds of blowing agent needed to produce a given volume of gas. Thus, use bf a low molecular weight blowing agent minimizes the blowing agent cost per unit of production.
It has been found that HFC blowing agents selected from those represented by formula (6) are ideally suited, with respect to the aforementioned properties, when used to make foam products with the polymeric resins of the units of formulae (l)-(5). Suitable HFC blowing agents of formula (6) used with a specific polymeric resin of the units of formulae (l)-(5) can be readily determined by conventional techniques.
The following HFCs are suitable blowing agents for the foams of the present invention. HFC-32 CH2F2
HFC-125 CF3CF2H
HFC-134' HCF2CF2F
HFC-134a CF3CFH2
HFC-143a CF3CH3 HFC-152 CH2F-CH2F
HFC-152a CH3~CHF2 HFC-227 EA CF3-CHF-CF3 HFC-356 MFF CF3-CH2-CH -CF3 HCC-365 MFC CF3_.CH -CF2-CH3 The preferred HFCs are those containing one and two carbon atoms.
The foam products of the present invention have a unique combination of properties making them environmentally acceptable both with respect to the atmosphere and also for disposal. Concerning disposal, they can be landfilled whereupon they will biodegrade and/or hydrolyze to harmless degradation products, or they can be recycled by hydrolysis, preferably under slightly acidic or basic conditions, to form monomeric units that can be used in the production of polymer. The foam products of the present invention can be made by conventional techniques. Thus, the polymeric resin with the blowing agent therein can be pressure extruded at an appropriate temperature below the degradation or reaction temperature of the resin and the blowing agent. The foamed product can be in the form of a sheet or a shaped article such as hamburger containers, trays, plates, boxes and the like. These products are particularly useful in food packaging and food service containers because of the combined properties of low toxicity and environmental acceptability.
In addition to polymer and blowing agent, conventional adjuvants can be included. Typical nucleants such as calcium silicate talc; processing aids such as mineral oils; extrusion aids such as dioctylphthalate (DOP) ; and color concentrates. The concentrations of the additives are generally independent of the amount of blowing agent. HFC manufacture is known in the art. See
"Aliphatic Fluorine Compounds", A. M. Lovelace et al. (1958) , p. 55.
EXAMPLE 1 Continuous production at the rate of 500 lbs./hr. of a foam sheet product is prepared by feeding to a 4-1/2"-6" tandem extrusion system with annular die and mandrel a mixture of 2-1/2 lbs. per hour of calcium silicate talc nucleating agent and 472.5 lbs./hr. of molten polylactic acid (85% L, the remaining 15% being D/L and a small amount of low molecular weight lactide and oligomer, the polymer having a molecular weight of about 300,000). Into the molten polymer in the extruder is introduced 25 lbs. per hr. of CF3-CFH2 (HFC-134a) . The temperature of the material in the 4-1/2" extruder is maintained at 400-'F, and the pressure at 2500 lbs./sq. in. gauge. Prior to exiting the 6" extruder the temperature is dropped low enough to prevent cell collapse upon discharge from the extruder. The HFC comes out of solution in the polymer, forming an oriented degrad¬ able thermoplastic foam product. This product is rigid foam sheet 44 in. wide and 100 mils thick, having a density of 6 lbs. per cubic ft.
The sheet foam is then fed through a thermoformer where it is stamped into 12 in. circular plates.
Following the same procedures, sheets ranging from 50-100 mils thick are prepared and thermoformed into hinged food service containers.
EXAMPLES 2-6 Following the procedure of Example 1, there are formed plates and service containers of PHA/HFC foams from the ingredients listed below: Calcium
PLA Silicate
Blowing Composi- Talc
Ex. Agent M.W. #/hr. tions* #/hr. Nucleator
2 CH2F2 52 2.55 85% L 494.95 2.5 (HFC-32)
3 CH3CHF2 66 3.24 70% L 494.26 2.5 (HFC-152a)
4 CF3-CH2F 102 5 60% L 492.5 2.5 (HFC-134a) 5 CF3CHFCF3 170 8.33 75% L 489.17 2.5 (HFC-227 EA) 6 CF3CH2CF2CH3* 166 8.14 50% L 489.36 2.5 (HFC-365 MFC)
* The remaining PLA composition is D polylactic acid isomer plus less than 7% low molecular weight lactide and oligomer.

Claims

E CLAIM:
1. A product comprising foamed, degradable resin and a hydrofluorocarbon blowing agent.
2. The product of Claim 1 wherein the acid resin contains at least one acid unit selected from the formula
(1) (0(CR2R2)nCO)p (2) (0CRιR2C00CRιR2C0)q
(3 ) (0CRιR2CRι 20CRιR2C0) r
(4 ) (OCRιR2CFι.R2OCRιR CRιR2CO) Hs
Figure imgf000011_0001
wherein n is a whole number 2, 4 & 5, the total of p, q, r, s and t being 350 to about 5,000, and Ri or R , which can be the same or different, is hydrogen, hydrocarbyl containing 1 to 12 carbon atoms, or substituted hydrocarbyl containing 1 to 12 carbon atoms.
3. The product of Claim 1 wherein the poly-hydroxy acid units are selected from the group consisting of polylactide and polyglycolide.
4. The product of Claim 1 wherein the poly-hydroxy acid units comprise at least 50% of units of formula (1) .
5. The product of Claim 1 where over 50% of the polylactate resin is L-isotropic form polymer units.
6. The product of Claim 4 wherein the polymer resin contains less than 7% lactide and lactyllactate oligo er units of less than 450 molecular weight.
7. The product of Claim 1 wherein the blowing agent is selected from the formula
Figure imgf000012_0001
wherein all A's are independently hydrogen or fluorine and n = 1-4.
8. The product of Claim 7 wherein n = 1.
9. The product of Claim 7 wherein n = 2
PCT/US1991/004241 1990-07-16 1991-06-21 Degradable foam materials WO1992001737A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP91511016A JPH05508669A (en) 1990-07-16 1991-06-21 degradable foam material

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US55265790A 1990-07-16 1990-07-16
US552,657 1990-07-16

Publications (1)

Publication Number Publication Date
WO1992001737A1 true WO1992001737A1 (en) 1992-02-06

Family

ID=24206240

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1991/004241 WO1992001737A1 (en) 1990-07-16 1991-06-21 Degradable foam materials

Country Status (9)

Country Link
US (1) US5134171A (en)
EP (1) EP0539398A1 (en)
JP (1) JPH05508669A (en)
CN (1) CN1058221A (en)
AU (1) AU8007591A (en)
IE (1) IE912473A1 (en)
MX (1) MX9100210A (en)
PT (1) PT98330A (en)
WO (1) WO1992001737A1 (en)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0507554A1 (en) * 1991-04-01 1992-10-07 MITSUI TOATSU CHEMICALS, Inc. Degradable foam, process for its preparation and use of same
EP0510999A1 (en) * 1991-04-24 1992-10-28 MITSUI TOATSU CHEMICALS, Inc. Degradable polymer network
US5238968A (en) * 1991-04-24 1993-08-24 Mitsui Toatsu Chemicals, Inc. Process for preparing a degradable high polymer network
US5278196A (en) * 1993-03-25 1994-01-11 Great Lakes Chemical Corp. Hydrofluorocarbon compositions as blowing agents for cellular plastics
EP0592911A1 (en) * 1992-10-14 1994-04-20 BASF Aktiengesellschaft Method for manufacturing injection moulded foamed polylactide objects of high strength and stiffness
EP0601390A1 (en) * 1992-11-26 1994-06-15 BASF Aktiengesellschaft Expanded polylactides moulded bodies and process for their preparation
EP0662107A1 (en) * 1992-09-22 1995-07-12 BioPak Technology, Ltd. Degradation control of environmentally degradable disposable materials
US5444113A (en) * 1988-08-08 1995-08-22 Ecopol, Llc End use applications of biodegradable polymers
EP0683207A2 (en) 1994-05-19 1995-11-22 Mitsui Toatsu Chemicals, Incorporated L-lactic acid polymer composition, molded product and film
US5502158A (en) * 1988-08-08 1996-03-26 Ecopol, Llc Degradable polymer composition
US6323307B1 (en) 1988-08-08 2001-11-27 Cargill Dow Polymers, Llc Degradation control of environmentally degradable disposable materials

Families Citing this family (46)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0821332B2 (en) * 1984-05-10 1996-03-04 株式会社東芝 Color picture tube
US5767222A (en) * 1988-08-08 1998-06-16 Chronopol, Inc. Degradable polydioxaneone-based materials
US6740731B2 (en) * 1988-08-08 2004-05-25 Cargill Dow Polymers Llc Degradation control of environmentally degradable disposable materials
US6121337A (en) * 1990-03-23 2000-09-19 E. I. Du Pont De Nemours And Company Compositions containing 1,1,2,2-tetrafluoroethane (HFC-134) for closed-cell polymer foam production
US5912279A (en) * 1990-03-23 1999-06-15 E. I. Du Pont De Nemours And Company Polymer foams containing blocking agents
US5258488A (en) * 1992-01-24 1993-11-02 Cargill, Incorporated Continuous process for manufacture of lactide polymers with controlled optical purity
US5247058A (en) * 1992-01-24 1993-09-21 Cargill, Incorporated Continuous process for manufacture of lactide polymers with controlled optical purity
US5142023A (en) * 1992-01-24 1992-08-25 Cargill, Incorporated Continuous process for manufacture of lactide polymers with controlled optical purity
US6005067A (en) * 1992-01-24 1999-12-21 Cargill Incorporated Continuous process for manufacture of lactide polymers with controlled optical purity
US5247059A (en) * 1992-01-24 1993-09-21 Cargill, Incorporated Continuous process for the manufacture of a purified lactide from esters of lactic acid
US6326458B1 (en) 1992-01-24 2001-12-04 Cargill, Inc. Continuous process for the manufacture of lactide and lactide polymers
US5210108A (en) * 1992-07-29 1993-05-11 E. I. Du Pont De Nemours And Company Degradable foam materials
ATE173520T1 (en) * 1992-10-02 1998-12-15 Cargill Inc PAPER WITH A COATING OF MELTS-STABLE POLYMER AND METHOD FOR PRODUCING IT
US5338822A (en) * 1992-10-02 1994-08-16 Cargill, Incorporated Melt-stable lactide polymer composition and process for manufacture thereof
US6005068A (en) * 1992-10-02 1999-12-21 Cargill Incorporated Melt-stable amorphous lactide polymer film and process for manufacture thereof
WO1994008078A1 (en) 1992-10-02 1994-04-14 Cargill, Incorporated A melt-stable lactide polymer fabric and process for manufacture thereof
US5437924A (en) * 1993-07-08 1995-08-01 International Paper Company Compostable, biodegradable foam core board
US5563179A (en) * 1995-01-10 1996-10-08 The Proctor & Gamble Company Absorbent foams made from high internal phase emulsions useful for acquiring and distributing aqueous fluids
US5650222A (en) * 1995-01-10 1997-07-22 The Procter & Gamble Company Absorbent foam materials for aqueous fluids made from high internal phase emulsions having very high water-to-oil ratios
US5849805A (en) * 1995-01-10 1998-12-15 The Procter & Gamble Company Process for making foams useful as absorbent members for catamenial pads
MY132433A (en) * 1995-01-10 2007-10-31 Procter & Gamble Foams made from high internal phase emulsions useful as absorbent members for catamenial pads
US5759569A (en) * 1995-01-10 1998-06-02 The Procter & Gamble Company Biodegradable articles made from certain trans-polymers and blends thereof with other biodegradable components
US5770634A (en) * 1995-06-07 1998-06-23 The Procter & Gamble Company Foam materials for insulation, derived from high internal phase emulsions
US5633291A (en) * 1995-06-07 1997-05-27 The Procter & Gamble Company Use of foam materials derived from high internal phase emulsions for insulation
US5550167A (en) * 1995-08-30 1996-08-27 The Procter & Gamble Company Absorbent foams made from high internal phase emulsions useful for acquiring aqueous fluids
EP1035158A4 (en) * 1997-10-29 2002-01-30 Kanebo Ltd Resin composition with biodegradability and foamability
US6160028A (en) * 1998-07-17 2000-12-12 The Procter & Gamble Company Flame retardant microporous polymeric foams
US6245697B1 (en) 1998-11-12 2001-06-12 The Procter & Gamble Company Flexible mat for absorbing liquids comprising polymeric foam materials
EP1108751B1 (en) 1999-06-25 2007-10-24 Mitsui Chemicals, Inc. Aliphatic polyester composition for masterbatch and process for producing aliphatic polyester film with the composition
FR2838435B1 (en) * 2002-04-12 2004-06-18 Atofina COMPOSITION COMPRISING A MIXTURE OF MONO AND ALKYL POLYLACTYLLACTATES
WO2004099315A1 (en) * 2003-05-12 2004-11-18 Unitika Ltd. Biodegradable polyester resin composition, process for producing the same and foamed article and molded article using the same
US7645810B2 (en) * 2005-12-19 2010-01-12 Jsp Corporation Foamed sheet of polylactic acid resin, foam molding of polylactic acid resin and method of preparing foam molding
US8013031B2 (en) * 2004-03-26 2011-09-06 Natureworks Llc Extruded polylactide foams blown with carbon dioxide
US8309619B2 (en) 2004-09-03 2012-11-13 Pactiv LLC Reduced-VOC and non-VOC blowing agents for making expanded and extruded thermoplastic foams
JP4713274B2 (en) * 2005-08-23 2011-06-29 積水化成品工業株式会社 Method for producing polylactic acid resin foam
MX2008010781A (en) * 2006-02-22 2009-03-02 Pactiv Corp Expanded and extruded polyolefin foams made with methyl formate-based blowing agents.
ES2372988T3 (en) * 2006-12-14 2012-01-30 Pactiv Corporation EXPANDED AND EXTRUDED BIODEGRADABLE FOAMS AND REDUCED EMISSIONS MADE WITH BLOWING AGENTS BASED ON METHYR FORMAT.
US7977397B2 (en) * 2006-12-14 2011-07-12 Pactiv Corporation Polymer blends of biodegradable or bio-based and synthetic polymers and foams thereof
EP2271695B1 (en) * 2008-04-30 2016-11-02 NatureWorks LLC Extruded foams made with polylactides that have high molecular weights and high intrinsic viscosities
US8016980B2 (en) * 2008-11-25 2011-09-13 Dixie Consumer Products Llc Paper products
EP2690129A3 (en) * 2009-09-25 2014-02-26 Arkema Inc. Biodegradable foams with improved dimensional stability
US20120007267A1 (en) 2010-07-07 2012-01-12 Lifoam Industries Method of Producing Compostable or Biobased Foams
US8962706B2 (en) 2010-09-10 2015-02-24 Lifoam Industries, Llc Process for enabling secondary expansion of expandable beads
US10689498B2 (en) 2013-08-20 2020-06-23 Tepha, Inc. Closed cell foams including poly-4-hydroxybutyrate and copolymers thereof
US9480780B2 (en) 2013-11-05 2016-11-01 Tepha, Inc. Compositions and devices of poly-4-hydroxybutyrate
CN109762313B (en) * 2018-12-29 2020-09-22 恒天纤维集团有限公司 Preparation method of high-rate polylactic acid foamed sheet

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4422877A (en) * 1980-10-28 1983-12-27 Restech Research Limited Partnership Synthetic polymer-propellant compositions forming cold foamed structures having a temperature at least 30° C. below ambient temperature and containing open and/or closed cells
US4766182A (en) * 1986-12-22 1988-08-23 E. I. Du Pont De Nemours And Company Polylactide compositions
US4988740A (en) * 1989-06-15 1991-01-29 E. I. Du Pont De Nemours And Company Low density foamed thermoplastic elastomers

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4719246A (en) * 1986-12-22 1988-01-12 E. I. Du Pont De Nemours And Company Polylactide compositions

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4422877A (en) * 1980-10-28 1983-12-27 Restech Research Limited Partnership Synthetic polymer-propellant compositions forming cold foamed structures having a temperature at least 30° C. below ambient temperature and containing open and/or closed cells
US4766182A (en) * 1986-12-22 1988-08-23 E. I. Du Pont De Nemours And Company Polylactide compositions
US4988740A (en) * 1989-06-15 1991-01-29 E. I. Du Pont De Nemours And Company Low density foamed thermoplastic elastomers

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP0539398A4 *

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5444113A (en) * 1988-08-08 1995-08-22 Ecopol, Llc End use applications of biodegradable polymers
US6323307B1 (en) 1988-08-08 2001-11-27 Cargill Dow Polymers, Llc Degradation control of environmentally degradable disposable materials
US5502158A (en) * 1988-08-08 1996-03-26 Ecopol, Llc Degradable polymer composition
EP0507554A1 (en) * 1991-04-01 1992-10-07 MITSUI TOATSU CHEMICALS, Inc. Degradable foam, process for its preparation and use of same
US5447962A (en) * 1991-04-01 1995-09-05 Mitsui Toatsu Chemicals, Inc. Degradable foam and use of same
US5238968A (en) * 1991-04-24 1993-08-24 Mitsui Toatsu Chemicals, Inc. Process for preparing a degradable high polymer network
US5223546A (en) * 1991-04-24 1993-06-29 Mitsui Toatsu Chemicals, Inc. High polymer network
EP0510999A1 (en) * 1991-04-24 1992-10-28 MITSUI TOATSU CHEMICALS, Inc. Degradable polymer network
EP0662107A1 (en) * 1992-09-22 1995-07-12 BioPak Technology, Ltd. Degradation control of environmentally degradable disposable materials
EP0662107A4 (en) * 1992-09-22 1995-09-27 Biopak Technology Ltd Degradation control of environmentally degradable disposable materials.
EP0592911A1 (en) * 1992-10-14 1994-04-20 BASF Aktiengesellschaft Method for manufacturing injection moulded foamed polylactide objects of high strength and stiffness
EP0601390A1 (en) * 1992-11-26 1994-06-15 BASF Aktiengesellschaft Expanded polylactides moulded bodies and process for their preparation
US5278196A (en) * 1993-03-25 1994-01-11 Great Lakes Chemical Corp. Hydrofluorocarbon compositions as blowing agents for cellular plastics
EP0683207A2 (en) 1994-05-19 1995-11-22 Mitsui Toatsu Chemicals, Incorporated L-lactic acid polymer composition, molded product and film

Also Published As

Publication number Publication date
MX9100210A (en) 1992-02-28
EP0539398A1 (en) 1993-05-05
JPH05508669A (en) 1993-12-02
CN1058221A (en) 1992-01-29
IE912473A1 (en) 1992-01-29
US5134171A (en) 1992-07-28
AU8007591A (en) 1992-02-18
EP0539398A4 (en) 1993-03-16
PT98330A (en) 1992-05-29

Similar Documents

Publication Publication Date Title
WO1992001737A1 (en) Degradable foam materials
US5210108A (en) Degradable foam materials
US5116880A (en) Biodisintegrable thermoplastic resin foam and a process for producing same
CA1110399A (en) Rigid polyurethane foam containing polyester residue digestion product
AU708997B2 (en) Stability control agent composition for polyolefin foam
US5314927A (en) Polyester foamed articles and method for producing the same
EP0880556A4 (en) A short time frame process for producing extruded closed cell low density propylene polymer foams
US5162381A (en) Process for preparing thermalplastic foam
JP2000136261A (en) Foaming particle and production of the same
HUP0004460A2 (en) Foams comprising 1,1,2,2-tetrafluoro-ethane and a low solubility co-blowing agent and a process for making this foams
JP2002020526A (en) Expandable resin beads
US4923654A (en) Blowing agent for expandable polymeric foams
JP3802681B2 (en) Expandable resin composition having biodegradability
JPH10114833A (en) Polyglycolic acid foam
JP4582871B2 (en) Non-crosslinked resin foamable particles
JP3811747B2 (en) Expandable resin composition having biodegradability
JP4293489B2 (en) Method for producing foamed molded article having biodegradation
JP3394063B2 (en) Lactic acid-based polymer foam molded article and method for producing the same
JP2004217923A (en) Biodegradable foamed beads and method for preparation of the same and biodegradable foamed molding
JP4583160B2 (en) Biodegradable laminated foam sheet and molded body thereof
JP2001098104A (en) Expanded particle having biodegradability and mold thereof
JP2001098044A (en) Polylactic acid resin composition having biodegradability and expandability
JP2004107505A (en) Method for producing foamed and molded product
JP2003286360A (en) Biodegradable polyester resin foamed material and its manufacturing method
JP2000136255A (en) Polylactic acid-based foam and its production

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AU BB BG BR CA CS FI HU JP KP KR LK MC MG MW NO PL RO SD SU

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE BF BJ CF CG CH CI CM DE DK ES FR GA GB GN GR IT LU ML MR NL SE SN TD TG

WWE Wipo information: entry into national phase

Ref document number: 1991911836

Country of ref document: EP

WWP Wipo information: published in national office

Ref document number: 1991911836

Country of ref document: EP

WWW Wipo information: withdrawn in national office

Ref document number: 1991911836

Country of ref document: EP

NENP Non-entry into the national phase

Ref country code: CA