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WO2002022339A1 - Articles de mousse a alveoles ouverts - Google Patents

Articles de mousse a alveoles ouverts Download PDF

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Publication number
WO2002022339A1
WO2002022339A1 PCT/US2001/028776 US0128776W WO0222339A1 WO 2002022339 A1 WO2002022339 A1 WO 2002022339A1 US 0128776 W US0128776 W US 0128776W WO 0222339 A1 WO0222339 A1 WO 0222339A1
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WO
WIPO (PCT)
Prior art keywords
ammonia
foaming agent
polyolefin
polymer composition
agent
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
PCT/US2001/028776
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English (en)
Inventor
Yozo Toei
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sekisui America Corp
Original Assignee
Sekisui America Corp
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 Sekisui America Corp filed Critical Sekisui America Corp
Publication of WO2002022339A1 publication Critical patent/WO2002022339A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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
    • C08J9/0061—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof characterized by the use of several polymeric components
    • 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
    • C08J9/0014—Use of organic additives
    • C08J9/0023—Use of organic additives containing oxygen
    • 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
    • C08J9/06—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 chemical blowing agent
    • C08J9/10—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 chemical blowing agent developing nitrogen, the blowing agent being a compound containing a nitrogen-to-nitrogen bond
    • 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
    • C08J2205/00—Foams characterised by their properties
    • C08J2205/04—Foams characterised by their properties characterised by the foam pores
    • C08J2205/05—Open cells, i.e. more than 50% of the pores are open
    • 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
    • C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
    • C08J2323/26—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers modified by chemical after-treatment
    • 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
    • C08J2423/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers

Definitions

  • polyurethane foam is used in many industrial areas, for example as automotive, furniture and packaging materials.
  • polyurethane foam has the disadvantages of poor weatherability and water resistance.
  • the most popular open-cell foams derived from polyurethane degrade easily when exposed to ultraviolet rays and ozone.
  • Polyolefin foams are considerably more durable than polyurethane and are used in large quantities as heat insulating materials, packaging materials, and cushioning materials. They are typically closed-cell, and therefore are not suitable for applications where water absorptivity and breathability are required.
  • breathable, open-cell polyolefin foams are coarse in cell size, poor in hand, and have limited applicability.
  • a crosslinked foam of a polyolefin obtained according to a usual method has an open cell percentage of less than 20%, yielding a foam product that is not retentive and inflexible.
  • US patent 5,348,795 describes a polyolefin open cell foam prepared by direct foaming. The resultant foam is not crosslinked or lightly crosslinked, so it has very little thermal stability and resilience.
  • US Patent Nos. 3,950,278 and 4,424, 181 also describe lightly crosslinked polyolefin open cell foam articles.
  • US Patent No. 4,501,711 shows polyolefin open cell foam with chemical crosslinking using very low molecular weight ethylene- vinyl acetate copolymer (EN A). These articles have better thermal stability than non-crosslinked polyolefin open cell foams, but are still not good enough to satisfy general demand.
  • a crosslinked foam has first been prepared and the resulting product has then been subjected to a secondary processing to destroy the closed cells for conversion to open cells by heat expansion.
  • This process gives rise to a foam that lacks resiliency and causes "bottom- out".
  • uniform cell opening is difficult to achieve and the resulting cells are coarse in size.
  • an open cell foam is prepared by pressing closed cells causing the cells to rupture. The process described in US Patent No. 5,859,076 to Kozma et. al creates new open cell foam by a crushing process; however, the process also damages the overall foam properties.
  • an open cell polyolefin foam of excellent thermal stability, flexibility and resilience is obtained by coordinating the progression of the foaming and crosslinking reactions so that a high level of crosslinking is achieved only after the open cell structure of the polymer is formed.
  • a process for producing open cell, cross linked polyolefin foam article includes providing a polymer composition including a functionalized polyolefin having reactive moieties that are reactive to ammonia, and a foaming agent wherein a majority of the foaming agent is a chemical foaming agent capable of producing ammonia.
  • the chemical foaming agent is activated to generate a gaseous blowing agent and ammonia, whereby the blowing agent forms an open cell foam article and the ammonia chemically crosslinks the polyolefin at the ammonia-reactive sites. Because the primary crosslinking agent, ammonia, is generated as a by-product of the foaming agent decomposition, crosslinking does not occur until foaming is substantially complete.
  • a method for a producing an open-celled, cross linked polycarbonate foam article includes providing a polymer composition comprising a polycarbonate having a functional moiety reactive to ammonia and a foaming agent wherein the foaming agent is a chemical foaming agent capable of producing ammonia, activating the chemical foaming agent to generate a gaseous blowing agent and ammonia, whereby the blowing agent forms an open cell foam article and the ammonia chemically crosslinks the polycarbonate at the ammonia- reactive sites.
  • closed cells used herein means cells in which bubbles are surrounded by resin membranes in the foam and are not interconnected or open to adjacent cells of the foam.
  • open cells means cells made up of resin membranes of the foam that are interconnected and open to adjacent cells of the foam.
  • a “foaming agent” is a compound used to introduce cells or pores into a polymer resin.
  • chemical foaming agent is meant a compound, or mixture of compounds, that decomposes or reacts at elevated temperatures to generate one or more gases, which form pores or cells in a polymer resin.
  • the chemical foaming agent may generate gases by decomposition or when heated to form gaseous products.
  • a “physical foaming agent” is a gas or volatile compound that is in a vapor state at use temperatures to form pores or cells in a polymer resin.
  • ком ⁇ онент is meant a polyolefin containing functional groups along the polymer backbone or pendent to the polymer backbone.
  • a functionalized polyolefin is "reactive to ammonia” if it contains a chemical moiety along the polymer backbone or pendent to the polymer backbone that is capable of undergoing chemical reaction with ammonia.
  • exemplary reactive moieties include carbonyl, epoxide, anhydride and organic acid groups.
  • crosslinkable polymer is one that contains a chemical moiety along the polymer backbone or pendent to the polymer backbone that is capable of undergoing chemical reaction with a crosslinking agent to form a crosslink, or which is capable of being activated so that the polymer backbone undergoes crosslink, e.g., by activation with peroxides to induce free radical-initiated crosslinking. At least some of the crosslinkable chemical moieties are reactive to ammonia.
  • resin is meant a natural or synthetic polymer.
  • Gel fraction is used to describe the degree of crosslinking and may be determined by extraction with a solvent such as xylene.
  • Figure 1 is a plot of increasing pore content vs. gel fraction and illustrates the composition of materials in the prior art and the current invention
  • Figure 2 is an exemplary reaction scheme for the crosslinking of a polyolefin at a CO-site.
  • an open cell polyolefin foam of excellent thermal stability, flexibility and resilience is obtained by coordinating the progression of the foaming and crosslinking reactions so that a high level of crosslinking is achieved only after the open cell structure is formed, thereby providing a foamed article in the regime delineated by region 40.
  • open cell foam means a foam possessing an interconnection or opening between adjacent cells. There can be greater than about 40% open cells, preferably greater than 60%, more preferably greater than 80%. To provide adequate thermal stability, the gel level should be greater than 50%, preferable 60%, and more preferably greater than 70%. In particular, the foams of the invention exhibit dimensional change of less than 10% at 70 °C and a compression set of less than 12%.
  • a process for producing an open cell crosslinked polyolefin foam article includes providing a polymer composition including a functionalized polyolefin having functional moieties that are reactive to ammonia and a chemical foammg agent capable of producing ammonia.
  • the chemical foaming agent is activated to generate a gaseous blowing agent and ammonia (NH 3 ), whereby the blowing agent forms an open cell foam article and the ammonia chemically crosslinks the polyolefin at the ammonia-reactive sites.
  • This reaction helps to enhance the thermal stability of the open cell foam by crosslinking the resin after foaming has taken place or after a significant degree of foaming is complete.
  • the process employs a polymer resin that can react with NH 3 , for example, a polyolefin functionalized with carbonyl, organic acid, anhydride or epoxide groups.
  • Polyolefins include polymers of ethylene and propylene, including high density polyolefin and low density polyolefin, and mixtures thereof. It also includes conventional polyethylene copolymer derivatives, such as vinyl ester, alkyl acrylate and alkyl methacrylate and ⁇ -olefin copolymers of polyethylene. It also may include polymer blends.
  • the polyolefin may be blended with polymers such as polyethylene (PE), polypropylene (PP) and ethylene vinyl acetate (EVA). Suitable blends are those, which provide a polymer resin having a melt index in the range of about 0.3 to 50, and preferably about 0.3 to 10. PE, PP, and EVA have melt indices in the range of 0.3 to 50.
  • Functionalized polyolefins may be prepared using well-known methods. For example, unsaturated monomers having the desired ammonia-reactive functional group may be used in the preparation of the polyolefin. Reactive unsaturated monomers that may be used to obtain suitable functionalized polyolefins include any monomer having a group that can react with NH 3 , for example, carbon monoxide, maleic anhydride, epoxide, glycidyl methacrylate, acrylic or methacrylic acid or and the like.
  • suitable carbonyl-functionalized polyolefins include Elvaloy® 741 ,742, 4924, HP441 (Dupont) and the like, which is a polyolefin resin containing a carbonyl group (derived from carbon monoxide).
  • Exemplary acid-functionalized polyolefins include Fussabond® (Dupont) and Polybond® (Witco), which are polyolefin resins containing maleic anhydride and/or acrylic groups.
  • Suitable epoxide-functionalized polyolefins include Elvaloy® PTW (Dupont). These commercially available resins are commonly used as asphalt modifiers or polymer plasticizers.
  • the level of ammonia reactive functional group may vary. In preferred embodiments, at least 1 wt%, and preferably at least 3 wt% of the monomer source for the ammonia-reactive functional moiety is used.
  • the olefin content of the polymer resin should be at least 60 wt%, and preferably the monomer source for the ammonia-reactive functional moiety is no more than 20 wt% of the polymer resin.
  • Elvaloy® 741, 742 and 4942 has 10-12% content of functional group by weight and around 70% polyolefin content.
  • Polybond® includes 1-6% acrylic acid and maleic anhydride and 94-99% polyolefin.
  • the functional group content provides an upper limit to the degree of crosslinking obtainable by reaction with ammonia.
  • the foaming agent includes a compound or mixture of compounds, which generates an inert gas such as nitrogen by thermal decomposition, and which also produces ammonia as a by-product when it decomposes.
  • Ammonia is traditionally considered an undesired by-product of the foaming reaction because it is corrosive and represents an environmental hazard requiring additional safety precautions when handling.
  • Most compounds considered suitable for use as foaming agents produce low levels of ammonia as a by-product, typically in the range of 1-5% wt% of gaseous product. The actual amount will vary depending upon the foaming agent.
  • Compound 100 represents a polyolefin containing a carbonyl functional group and may be, for example, an Elvaloy polymer resin.
  • the carbonyl group reacts with ammonia, most likely through ammonia nucleophilic attack on the electropositive carbonyl carbon, although the invention is not limited to any particular mode of action or reaction.
  • the reaction product may be compound 110 having a crosslink 120 between adjacent polymer strands.
  • the crosslink includes a nitrogen atom, whose source is the ammonia reactant.
  • Suitable chemical foaming agents include azo compounds such as azodicarbonamide, p- toluenesulfonyl semicarbazide, 5-phenyltetrazole, nitroso compounds, such as N,N'-dinitrosopentamethylene-tetramine, and aromatic hydrazides, such as p,p'-oxybenzenesulfonyl hydrazide may generally be used as the foaming agent.
  • azo compounds such as azodicarbonamide, p- toluenesulfonyl semicarbazide, 5-phenyltetrazole, nitroso compounds, such as N,N'-dinitrosopentamethylene-tetramine
  • aromatic hydrazides such as p,p'-oxybenzenesulfonyl hydrazide may generally be used as the foaming agent.
  • These chemical foaming agents may be used singly or in combination.
  • blowing agents such as volatile organics or other similar vaporous compounds.
  • blowing agents may be added at low levels, e.g., less than 50 wt% of total foaming/blowing agent, and preferably in the range of 0-15 wt%, and include aliphatic hydrocarbons having 1-9 carbon atoms, halogenated hydrocarbons of 1-4 carbon atoms, and aliphatic alcohols of 1-3 carbon atoms.
  • Other suitable blowing agents include carbon dioxide, nitrogen, argon, water, air, nitrogen or helium. Addition of physical foaming agents may be desired to produce a very low density foam.
  • the foaming agent will have a decomposition temperature (with resultant release of gaseous materials) in the range of about 180-250°C, and preferably in the range of about 180-230 °C, and for example about 220 °C.
  • the temperature of decomposition is selected to produce the desired level of ammonia byproduct. At higher temperatures, more ammonia is produced. For example, when using azodicarbonamide, ammonia is 5% of the gaseous product at 250°, but only 1%> of the gaseous product at 180-190°C.
  • the decomposition is carried out at 220°C. Additives may be included in the polymer composition to alter the temperature of decomposition.
  • a foaming adjuvant such as stearic acid or zinc stearate
  • stearic acid or zinc stearate may be used; for example, in a proportion of 5 or less parts by weight per 100 parts by weight of the total resin components.
  • the amount of the foaming agent may be varied depending upon the desired expansion ratio, though the foaming agent is preferably used in amount of 1 to 50 parts by weight per 100 parts by weight of the total resin component, and preferably about 5-25 parts per 100 parts total resin component. Since crosslinking is a result of the ammonia-level generated upon decomposition of the foaming agent, the foaming agent is a factor in determining the degree of crosslinking. The degree of crosslinking may be controlled by both the amount of foaming agent and foaming time.
  • the secondary crosslink agent may be used to increase the crosslink density and, thereby, the thermal stability of the foam.
  • the secondary crosslinking agent may be one that reacts more slowly than ammonia, so that the ammonia reaction is substantially complete before the second crosslinking agent can react.
  • the secondary crosslinking agent may be one that does not react under conditions established for the foaming agent decomposition and ammonia reaction. Once these reactions are complete, conditions may be altered to initiate the secondary crosslinking reaction. For example, a secondary crosslinking agent may be selected which does not react at the temperature selected for foaming agent decomposition. Thereafter, the temperature may be raised to initiate the second crosslinking reaction.
  • Suitable crosslinking agents include an organic peroxide that can thermally be decomposed, preferably at a temperature other than that used to initiate foaming.
  • the organic peroxide used in this process has a lhour half-life temperature of between 110°C and 200°C.
  • suitable secondary crosslinking agents are 2,5-dimethyl-2,5-di(tert- butylperoxy)hexane-3, di-tertiary-butyl peroxide, 2,5-dimethyl-2,5-di(tert- butylperoxy)hexyne, tert-butyl cumyl peroxide, di-(2-tert- butylperoxyisopropyl)benzene, dicumyl peroxide, butyl 4,4-di-(tert- butylperoxy)valerate, l,l-di(tert-butylperoxy)-3,3,5-trimetylcyclohexane, and tert-butyl peroxybenzoate.
  • the proportion of the crosslinking agent is preferably 0.1 to 4 parts by weight per 100 parts by weight of the total resin components.
  • acceptable foam articles are typically obtained in certain ranges of crosslinking density or level. Too much crosslinking can render the foam inelastic and lacking resiliency. Too little crosslinking can be detrimental to physical properties such as compression or thermal stability. It is desirable to select crosslinking levels that provide the foam with the desired performance properties. Suitable crosslink levels may be determined by the level of functional moiety incorporated into the functional polyolefin. In preferred embodiments, at least 3 wt% and preferably no more than 20 wt% ammonia-reactive functional moiety is used. The degree of crosslinking is also controlled by the level of crosslinking agent used, including both the ammonia and secondary crosslinking agent.
  • Crosslinking level is defined by the gel content of the composition, and may be in the range of 25% to 98%.
  • gel fraction is preferably in the range of greater than 50%, preferable 60%, and more preferably greater than 70%.
  • secondary crosslinking agents such as peroxide, may be used to increase the gel fraction.
  • Gel content may be determined, for example, by extraction with a solvent such as xylene.
  • gel fraction is defined as 100*W g /W s , where W g is the initial weight of the sample and W s is the weight of the sample after heating in xylene for 24 h at 120 °C.
  • coloring agents may appropriately be blended with the above composition to meet application criteria.
  • surfactant foaming kicker, anti-oxidant, UN stabilizer, anti-bacterial agents, flame retardant, lubricant, adhesion promoter, process aids, colorants, monomer and/or other resins and/or fillers may appropriately be blended with the above composition to meet application criteria.
  • Any surfactant suitable for polyolefin for example, polyether modified silicone fluid, methylstyryl modified silicone fluids and alkyl modified and the like may be used.
  • a surfactant may be used to stabilize bubbled formed during the foaming operation. It will be immediately apparent to one of ordinary skill in the art which of the many available surfactants are appropriate to improve foam stability.
  • the foaming agent composition of this invention may take any form means that open-cell foam can be produced from pellets, powder, film, and sheet.
  • the foams can be produced both in a continuous in-line process or batch process.
  • the polymer composition is mixed using an extruder or kneader and is prepared below the temperature at which the foaming agent decomposes.
  • the compounded composition is formed into the desired shape and is then heated to the foaming agent decomposition temperature to make open cell foam.
  • methods of combining the components of the foamable mixture include melt-blending or liquid mixing. Any or all of the ingredients may be pulverized or comminuted by conventional methods. Melt-blending can be accomplished in a batch or continuous process, using for example, an internal mixture such as a Banbury mixer, a single or twin screw extruder, or roll mills. It is preferred that mixing be carried out under temperature control, in particular to avoid premature decomposition of the foaming agent. Components can be added together or sequentially. Once mixed, the blend can be formed into a desired shape, for example, sheets by passing the blend through a two roll mill. The sheets can be cut into any desired shape and heated to initiate the foaming and crosslinking process.
  • the blend may be shaped in a continuous extrusion process, or by compression molding.
  • the time and temperature of the foaming process may be modified to obtain a foam of optimized properties.
  • the open-cell content of the foam or its permeability to gases and fluids may be enhanced by mechanical means.
  • the foam may be crushed or mechanically perforated.
  • the inventive foamed articles form open cells more readily when crushed than conventional closed-cell polyolefin foams. While not bound by any particular mode of operation, it is hypothesized that formation of additional open cells occurs more readily once cell walls have been perforated initially in the foaming step.
  • the foamed article may be crushed by passage through feed rollers with decreasing nip thicknesses.
  • the gap between rollers is arranged so as to decrease as the foam passes between successive rollers, crushing the foam and causing remaining closed cells to rupture, and thereby increasing the open cell content of the foam. Due to the high resiliency of the inventive foam articles, they recover readily from the crushing operation and quickly regain their original shape and thickness.
  • the rollers may include pins on their surfaces that penetrate the foam and further increase the open cell content of the foam. The pins may be used on one or both rollers, and may have a variety of shapes.
  • the foam may be crushed at temperatures at which the article is thermally stabile, for example in the range of about 50 °C to 100 °C.
  • the open cell foam articles of the invention have good weatherability, as is typical for polyolefin compositions. They also are permeable fluids and gases.
  • the foams may be used in a variety of applications, such as packaging and insulation.
  • open cell, crosslinked foams containing polycarbonate may be prepared using the method of the invention.
  • a polymer composition which includes a polycarbonate, and a foaming agent wherein a majority of the foaming agent is a chemical foaming agent capable of producing ammonia.
  • the chemical foaming agent is activated to generate a gaseous blowing agent and ammonia, whereby the blowing agent forms an open cell foam article and the ammonia chemically crosslinks the polycarbonate at the ammonia- reactive sites.
  • Common polycarbonates include polycarbonates of bisphenol.
  • Example 1-6 Funtionalized polyethylene (Elvaloy 4924), polyethylene copolymer (Elvax 265), surfactant (silicone fluid), foammg adjuvant (stearic acid), foaming agent (azodicarbonamide), foaming catalyst (zinc oxide), and antoxidant (Mark 328, Uniroyal Comany) were combined in the amounts listed in Table 1.
  • KF412 an alkyl-modified silicone fluid supplied by Shinetsu Silicones of America.
  • Open Cell Ratio is determined according to D2856-94 by ultrapycnometer 1000 supplied by Quantachrome.
  • Compression was determined according to ASTM D3575-93 as follows. The test specimens were cut into 50 mm by 50 mm squares and stacked to a thickness of about 25 mm to provide an initial sample thickness (t(0)). The samples were placed in a compressive device and compressively deflected to 50%> of their original thickness for 22 hours. Final thickness (t(f)) was measured after allowing for a 24 hour recovery. Compression set is defined as 100*(t(0) - t(f))/T(0). Dimensional change was also determined under ASTM D3575. The test specimens were cut into 250 mm by 250 mm squares and the length (L(0)) was determined. The samples were then placed in an over temperature controlled at 70 °C for 24 h. The sample was then removed and cooled at room temperature for 2 h before measuring the length (L9f)). The %dimensional change is defined as 100*(L(f) - L(0))/L(0).
  • foamed polyethylene articles prepared using ammonia-reactive functionalized polyethylene possess high levels of open cells (80-95%) and high levels of crosslinking (53-62% gel fraction). Furthermore, the exception compression set values (10-12%) make these materials suitable for use as seals and cushioning. Due to their demonstrated thermal stability (dimensional changes of 7-9%), they are also suitable for use in high temperature environments.

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  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Emergency Medicine (AREA)
  • Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)

Abstract

L'invention concerne un article en mousse de polyoléfine à alvéoles ouverts obtenus par un procédé qui consiste à mettre en oeuvre une composition polymérique contenant une polyoléfine fonctionnalisée comprenant des fragments fonctionnels réactifs à l'ammoniac et un agent d'expansion chimique pouvant produire de l'ammoniac. Le procédé consiste ensuite à activer l'agent d'expansion chimique pour obtenir un gonflant gazeux et de l'ammoniac. Ledit gonflant forme un article de mousse à alvéoles ouverts et l'ammoniac réticule chimiquement la polyoléfine au niveaux des sites de réaction à l'ammoniac.
PCT/US2001/028776 2000-09-15 2001-09-12 Articles de mousse a alveoles ouverts Ceased WO2002022339A1 (fr)

Applications Claiming Priority (2)

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US66244200A 2000-09-15 2000-09-15
US09/662,442 2000-09-15

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WO2002022339A1 true WO2002022339A1 (fr) 2002-03-21

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7291382B2 (en) 2004-09-24 2007-11-06 Kimberly-Clark Worldwide, Inc. Low density flexible resilient absorbent open-cell thermoplastic foam
US7358282B2 (en) 2003-12-05 2008-04-15 Kimberly-Clark Worldwide, Inc. Low-density, open-cell, soft, flexible, thermoplastic, absorbent foam and method of making foam
US8158689B2 (en) 2005-12-22 2012-04-17 Kimberly-Clark Worldwide, Inc. Hybrid absorbent foam and articles containing it
WO2014040913A1 (fr) 2012-09-11 2014-03-20 Sika Technology Ag Agent moussant thermoplastique
WO2017112388A1 (fr) * 2015-12-22 2017-06-29 Dow Global Technologies Llc Procédé de fabrication d'un article en polyoléfine et composition de celui-ci
WO2017112389A1 (fr) * 2015-12-22 2017-06-29 Dow Global Technologies Llc Procédé de fabrication d'article à partir de polyoléfine
EP3231836A1 (fr) * 2016-04-13 2017-10-18 Autoneum Management AG Procede de preparation d'une mousse thermoplastique à alvéoles ouvertes
US11149127B1 (en) 2020-03-27 2021-10-19 Poragen LLC Biocompatible porous materials and methods of manufacture and use

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US3780140A (en) * 1971-08-06 1973-12-18 Du Pont Ethylene/carbon monoxide polymer compositions
US4532307A (en) * 1983-07-22 1985-07-30 Du Pont-Mitsui Polychemicals Co., Ltd. Polymer composition
US5356941A (en) * 1992-02-28 1994-10-18 Lisco, Inc. Game balls having improved core compositions

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3780140A (en) * 1971-08-06 1973-12-18 Du Pont Ethylene/carbon monoxide polymer compositions
US4532307A (en) * 1983-07-22 1985-07-30 Du Pont-Mitsui Polychemicals Co., Ltd. Polymer composition
US5356941A (en) * 1992-02-28 1994-10-18 Lisco, Inc. Game balls having improved core compositions

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7358282B2 (en) 2003-12-05 2008-04-15 Kimberly-Clark Worldwide, Inc. Low-density, open-cell, soft, flexible, thermoplastic, absorbent foam and method of making foam
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US12492294B2 (en) 2020-03-27 2025-12-09 Poragen LLC Biocompatible porous materials and methods of manufacture and use

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