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
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/18—Manufacture of films or sheets
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/10—Homopolymers or copolymers of propene
  • C08L23/14—Copolymers of propene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F210/00—Copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
  • C08F210/04—Monomers containing three or four carbon atoms
  • C08F210/06—Propene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/10—Homopolymers or copolymers of propene
  • C08L23/14—Copolymers of propene
  • C08L23/142—Copolymers of propene at least partially crystalline copolymers of propene with other olefins
• • 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
  • C08J2323/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
  • C08J2323/10—Homopolymers or copolymers of propene
  • C08J2323/14—Copolymers of propene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2205/00—Polymer mixtures characterised by other features
  • C08L2205/02—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2314/00—Polymer mixtures characterised by way of preparation
  • C08L2314/06—Metallocene or single site catalysts

Definitions

• This invention relates generally to films, sheets, molded articles, extruded profiles, tubing or similar articles made from propylene ⁇ -olefin copolymers.
• the articles exhibit exceptional physical properties, including relatively low cold flow or creep. More specifically this invention relates to the use of certain propylene ⁇ - olefin copolymers (formed using a metallocene catalyst system) where the ⁇ -olefin is selected from ⁇ -olefins having 5 or more carbon atoms.
• BACKGROUND Polyolefin polymers are well known articles of commerce. The uses of polyolefins are many and well known to those of skill in the art. Polyolefins have many useful physical properties.
• polyolefins display unacceptable cold flow properties, that is, at room temperature or service temperature, they exhibit flow when subjected to low levels of stress for an extended period.
• Cold flow resistance is a property of importance in many polymer applications. Cold flow is defined as the non-recoverable deformation of a polymer article in response to a force or stress (well below the yield stress ofthe material), applied for an extended time at a selected temperature Different polymers will exhibit different resistances to cold flow.
• Polypropylene homopolymers and copolymers have come into wide use
• polypropylene has a wide range of commercial uses, from packaging films and sheeting to molded food containers and fibrous constructions employed for example in diapers and hospital gowns
• polypropylene has a wide range of commercial uses, from packaging films and sheeting to molded food containers and fibrous constructions employed for example in diapers and hospital gowns
• This classification includes ethylene
• random copolymers sometimes also known as random copolymers.
• this class has tended to be represented largely by copolymers of propylene and ethylene, usually made using Ziegler-Natta catalysts.
• Ziegler-Natta catalysts have been problematic in the past due to the lower reactivity of these catalysts towards higher alpha-olefins.
• the Ziegler-Natta catalyzed propylene-ethylene copolymers have generally found use based on their substantially different properties when compared to polypropylene homopolymers. Broadly, the differences between Ziegler-Natta catalyzed homopolymers and propylene-ethylene copolymers are seen in such properties as lower melting point, greater flexibility, better clarity and slightly improved toughness for the copolymer.
• EP 0 495 099 Al to Mitsui Petrochemical Industries suggests a method for polymerization ofthe propylene ⁇ -olefins utilizing metallocene-alumoxane catalyst systems.
• the document also suggests a propylene ⁇ -olefin copolymer where the propylene is present from 90-99 mole % and the ⁇ -olefin is present from 1-10 mole %.
• the propylene ⁇ -olefin copolymers would have a narrow molecular weight distribution (Mw/Mn), the copolymer would have a low melting point, and the copolymers have excellent softness.
• Mw/Mn narrow molecular weight distribution
• the document also suggests a straight line relationship between T m and propylene content, however, no distinction is drawn to the melting point depression effect of different ⁇ -olefins.
• EP 0 538 749 Al to Mitsubishi Petrochemical Co. suggests a propylene copolymer composition to produce a film having excellent low-temperature heat sealing, where the composition has 1 to 70 wt% of A and 30-99 wt% of B where: A is a propylene ethylene or ⁇ -olefin copolymer where the ⁇ -olefin has 4-
• B is a propylene ethylene or ⁇ -olefin copolymer where the ⁇ -olefin has 4- 20 carbon atoms and a MJM ⁇ of 3.5 to 10.
• Copolymer A is polymerized by a metallocene catalyst system.
• Copolymer B is polymerized by a Ziegler- type catalyst. Substantially all examples utilize propylene-ethylene copolymers or propylene homopolymers.
• EP 0 318 049 Al to Ausimont suggests crystalline copolymers of propylene with minor portions of ethylene and/or ⁇ -olefins.
• the copolymers are said to have very good mechanical properties.
• the copolymers are polymerized in the presence of metallocene compounds.
• the examples of this document show propylene- ethylene and propylene- 1-butene copolymers.
• PVC polyvinyl chloride
• Fresh meat wrap is an example ofthe deficiency of polyolefins when compared to PVC.
• PVC films are known and valued for their ability to "snap back" after deformation. This snap-back attribute is directly related to the film's ability to resist cold flow. In retail meat displays, such deformation is caused when the packaged meat is handled. Because of its "snap back", meat wrapped in PVC film, even after handling, does not show the effects of such handling.
• Polyolefins have repeatedly been tried in film applications such as meat wrap with little commercial success, because when deformed by handling, a polyolefin's tendency to cold flow leaves unacceptable finger marks or other depressions or distortions of the film even after the packaged meat itself has recovered (or substantially resumed the shape it had before deformation). Polypropylene and polyethylene ofthe polyolefins especially exhibit this deficiency, due to their relatively poor cold flow.
• PVC has many advantages in applications as discussed above as well as many others, PVC has several substantial drawbacks that have made its replacement by other plastics, such as polyolefins, a high priority in many of those applications.
• the density of PVC is substantially higher than most polyolefins.
• the density of most PVC is about 1.2 g/cc versus a density well below 1.0 g/cc for most polyolefins. This has a very practical effect, that a given unit of weight of PVC will yield substantially less product than a unit of polyolefin.
• a second drawback of PVC is that upon combustion, for example in waste or trash incineration, PVC will evolve hydrochloric acid.
• plasticizers such as phthalate esters used in flexible PVC.
• Polypropylenes can be molded or extruded into many shapes Conventional homopolypropylene and conventional copolymers of propylene and ethylene show creep or cold flow when subjected to a force or stress Additionally, polypropylenes are often blended with other materials to modify their properties, for example to give them rubbery or more rubbery characteristics
• Polyolefins such as polypropylene are not generally considered elastic, however, they are generally rigid and light weight Rubbers on the other hand are elastic, but are not rigid.
• Rubber products have generally found extensive use in applications which require elasticity and flexibility. Molding of rubber into a finished product entails a curing step, generally referred to as vulcanization, which requires the use of specialized molding machines, long cycle times and a number of complicated processing steps The rubber molding process, therefore, does not lend itself easily to mass production due to these processing difficulties It highly desirable to find a rubber or rubber like compound without the need for a vulcanization step
• flexible plastics such as flexible vinyl chloride resins, ethylene/vinyl acetate copolymers and low density polyethylenes generally have good flexibility, fabrication and molding properties, but suffer from poor heat resistance, and resiliency (rebound) which greatly restrict their utility
• thermoplastic elastomers The classical TPE structure involves a matrix of an elastomer such as, for example, a polybutadiene, polyester or polyurethane, tied together by thermoplastic junction regions.
• An elastomer such as, for example, a polybutadiene, polyester or polyurethane
• a well known example of a TPE is Shell's Kraton ® G, triblock of styrene and hydrogenated polybutadiene, where the thermoplastic crosslinking points are small domains of glassy polystyrene held together by rubbery polybutadiene blocks.
• This structure leads to behavior similar to vulcanized elastomers at ambient temperature but, at temperatures above the polystyrene softening point, the system undergoes plastic flow.
• thermoplastic olefins A subset of thermoplastic elastomers, embodying only olefin based polymers, is referred to as thermoplastic olefins (TPO).
• TPO thermoplastic olefins
• a typical TPO comprises a melt blend or like mixture of at least one thermoplastic polyolefin resin, with at least one olefin copolymer elastomer (OCE).
• OCE olefin copolymer elastomer
• the thermoplastic polyolefin resin will give the TPO rigidity and temperature resistance while the elastomer imparts flexibility and resilience as well as improving the toughness ofthe material.
• TPOs find particular application in the auto industry for flexible exterior body parts such as, for example, bumper covers, nerf strips, air dams and the like. In such applications, it is desired that the TPO have good resiliency (ability ofthe part to return to its original shape after deformation), impact strength at low temperatures, flexibility, high heat distortion
• TPOs Other application for TPOs include films, footwear, sporting goods, electric parts, gaskets, water hoses and belts, to name just a few. Particularly in films, elasticity and clarity properties are important. Other ofthe aforementioned properties will be important depending upon the desired application.
• TPOs suffer compared to TPEs such as Kraton G due to the inability ofthe polypropylene matrix to resist stress over relatively long periods of time.
• TPEs exhibit cold flow resistance and resiliency that generally exceeds that of TPOs. This cold flow resistance and resiliency enables TPEs to be used in applications where the relatively poor cold flow and resiliency of polyolefins such as polypropylene unacceptable.
• Such applications include molded articles for automobiles and appliances. In molded articles, shape is often a critical parameter. Cold flow due to a contained load or due to an applied force could cause unacceptable non-recoverable deformation in a molded part. Additionally, much less weight and time would be necessary to cause a load-set or deformation due to a static load if the molded parts are fabricated from most polyolefins rather than TPOs. Versus TPEs, the performance of most polyolefins would be even poorer.
• TPEs have many advantages as discussed above, their cost makes them unacceptable for some applications and marginally acceptable in others. While much less expensive than TPEs, TPOs on the other hand are not an ideal choice either due to the above mentioned defensive physical properties. There is therefore a need for a polyolefin, specifically a polypropylene copolymer that will resist cold flow to a sufficient extent that it could replace conventional PPs or the polypropylene component in blends, eg TPOs, in many applications.
• propylene copolymers made utilizing metallocene catalyst systems to polymerize propylene with ⁇ -olefin comonomers having 5 or more carbon atoms show a surprising enhancement in important physical properties when compared to propylene copolymers utilizing alpha-olefins of 4 carbon atoms or less (for purposes of this application, this classification includes ethylene).
• this classification includes ethylene.
• the most striking step change is evidenced in the present invention in cold flow resistance or creep resistance values on articles made from materials made according to this embodiment. These changes will be noted in articles made from the copolymer themselves, or in parts fabricated from a TPO containing these copolymers.
• extruded, molded and calendared articles such as film, tubing, extruded profiles, molded parts, sheets, or other fabricated articles are comprised of an isotactic statistical copolymer of propylene and HAO and alternatively TPOs utilizing these copolymers.
• the HAO is present in the range of from about 0.2 to about 6 mole percent.
• the copolymer will have a molecular weight distribution (MWD) M ⁇ /M,, (weight average molecular weight/number average molecular weight) ⁇ 5 and a peak melting point (DSC) in the range of from about 100° C to about 145° C.
• An article made from these copolymers will exhibit improved creep or cold flow resistance when compared to a propylene ethylene copolymer of similar flexability.
• Fig. 1 shows the effect of comonomer on melting point depression in a propylene copolymer.
• the present invention concerns certain classes of fabricated polypropylene articles, and their uses. These articles have unique characteristics which make them well suited for use in certain applications. Flexible films, tubing, sheets, extruded profiles, molded articles and other articles made therefrom have superior cold flow resistance compared to extruded profiles and molded parts made from polypropylene-ethylene copolymers. A detailed description follows of certain preferred resins for use in fabricating articles that are within the scope of our invention, and preferred methods of producing these resins and their products.
• metallocene catalyst systems can be used to polymerize propylene statistical copolymers having properties which are highly desirable for conversion into various products.
• these resins are isotactic polypropylene statistical copolymers, the copolymers utilize propylene and one or more alpha-olefins.
• isotactic is intended to mean a polymer where propylene tacticity distribution will be greater than about 90 percent mmmm pentads, where is a meso diad, (m is defined as the same relative configuration of methyl groups of two successive monomer units (diad) to each other), preferably in the range of from about 94 to about 98 percent mmmm pentads, most preferably in the range of from about 95 to about 97 percent mmmm pentads, as determined by nuclear magnetic resonance (NMR).
• NMR nuclear magnetic resonance
• the polypropylene copolymers ofthe present invention are preferably produced using supported metallocene catalysts.
• the copolymers may be produced in fluidized bed or stirred bed gas phase reactors, slurry or bulk liquid reactors of tank or loop type, or other processes practiced for the polymerization of polypropylene. Series bulk liquid boiling pool reactors are preferred.
• Resins produced by the above referenced processes and catalysts can have alpha-olefin comonomers in the range of from about 0.2 mole percent to about 6 mole percent Above 6 mole percent, the resulting resin may make an extruded profile, or molded article with a melting point or softening point too low for most preferred applications Below 0.2 mole percent comonomer, the flexural modulus may become too high, leading to a product that may be too stiff for most of applications
• the alpha-olefin comonomer is present in the range of from about 0 4 to about 3 5 mole percent In a most preferred embodiment the alpha-olefin is present in the range of from about 0.5 to about 3 mole percent In the most preferred embodiment, the alpha-olefin is present in the range of from about 1 to about 3 mole percent
• the catalyst system comprises a silicon bridged bis (substituted 2-methyl-indenyl) zirconium dichloride or a derivative thereof, methyl alumoxane and an inorganic support
• dimethyl silyl bis (2-methyl-benzindenyl) zirconium dichloride is the metallocene of choice
• This preferred catalyst system is used to generate the propylene-ethylene and propylene-hexene resins used in the films whose properties are shown in Table 1
• it would be possible to copolymerize any alpha- olefin of 2 to 20 carbon atoms utilizing these and similar catalyst systems Further details regarding preparation ofthe catalyst system and production ofthe resin are provided in the examples that follow Characteristics of the Resins
• the polymers ofthe present invention are substantially isotactic in nature.
• the polymers will generally have a narrow molecular weight distribution, as characterized by the M ⁇ /M,,, (weight average molecular weight/number average molecular weight) (molecular weight distribution MWD), of ⁇ 5.
• M ⁇ /M, (MWD) is determined by Gel Permeation Chromatography (GPC), as is molecular weight.
• GPC Gel Permeation Chromatography
• Food law compliance can be an important criterion for articles made from these resins, such compliance usually directly affected by the extractable content of an article made from a resin.
• a standard of U.S. Food and Drug Administration as noted in 21 CFR ⁇ 177.1520 is to use the n-hexane reflux procedure, the maximum extractables level ofthe products ofthe present invention is expected to be less that about 5 wt%, preferably less than about 4 wt%, most preferably less than about 3 wt%.
• melt flow rates ofthe polymers ofthe present invention are in the range of from about 0.1 to about 5000 dg/ in.
• the melt flows are in the range of from about 0.5 to about 200 dg/min.
• the melt flow rates are in the range of from about 1 to about 100 dg/min. Melt flow rates are measured by ASTM D-1238 condition L.
• Films may be made by any techniques known by those of ordinary skill in the art. For example, blown films produced with an annular die and air cooling, or cast films using a slot die and a chill-roll for cooling are both acceptable techniques. Oriented films may be produced by either post extruder manipulation ofthe blown film through heating and orientation, or by longitudinal stretching of an extruded sheet followed by tentering techniques. Films are generally in the range of from about 0.2 to about 10 mils (5.08 to 254 ⁇ m).
• Sheet may be made either by extruding a substantially flat profile from a die, onto a chill roll, or alternatively by calendaring. Sheet will generally be considered to have a thickness of from 10 mils to about 100 mils (254 ⁇ m to 2540 ⁇ m), although sheet may be substantially thicker. Films or sheets for test pu ⁇ oses may be made by compression molding techniques, as well.
• Tubing may be obtained by profile extrusion.
• the tubing will generally be in the range of from about 0.31 cm (1/8") to about 2.54 cm (1 ") in outside diameter, and have a wall thickness of in the range of from about 254 ⁇ m (10 mils) to 0.5 cm (200 mils).
• Films made from the products of a version ofthe present invention may be used to contain food articles such as meat and snacks for instance. Such films may also be used to protect and display articles of apparel.
• Sheet made from the products of an embodiment of a version ofthe present invention may be used to form containers. Such containers may be formed by thermoforming, solid phase pressure forming, stamping and other shaping techniques may be used for foods such as meat or dairy products. Sheets may also be formed to cover floors or walls or other surfaces. Tubing made from the products of this invention may be used in medical, food, or other uses that will be apparent to those of ordinary skill in the art.
• Molded articles may be made by any techniques known to those of ordinary skill in the art. For example, molded articles may be fabricated by injection molding, blow molding, extrusion blow molding, rotational molding, and foam molding. Molded parts are found in many thicknesses of 500 ⁇ m (20 mils) or greater. For molded articles, the thickness of a cross section ofthe article will generally be in the range of from about 508 ⁇ m to about 2.5 cm.
• Molded articles for health care devices such as, for example, syringes are also contemplated.
• Table I sets forth the physical property data for a propylene-ethylene copolymer film and a propylene-hexene copolymer film meeting the description of this application. The film test is used as an indicator of molded article or extruded profile performance.
• the data in Table I show that other physical/mechanical properties of articles fabricated from the resins ofthe present invention will also show an improvement in value, as noted before, when compared to propylene copolymers of lower alpha-olefins.
• TDC time delayed compliance
• the technique uses the ratio ofthe TDC of a propylene- ethylene copolymer, to the TDC of a propylene-HAO copolymer.
• the ratio is represented by the symbol R ⁇ , where: TDC (of propylene-ethylene copolymer article)
• TDC of propylene-HAO article
• the resins to form each article are chosen such that the tensile modulus of each article is substantially the same as that ofthe other article.
• R ⁇ it is important that substantially all parameters that affect the physical properties ofthe articles in both the numerator and denominator ofthe ratio be the same.
• Such parameters include, but are not limited to: for the resins: molecular weights should vary by no more than 10% for the fabricated article: fabrication conditions and techniques; dimensions ofthe test specimen; post fabrication treatments; blend components; or additives It will be understood by those of ordinary skill in the art that comonomer content (either HAO or ethylene) can be varied for pu ⁇ oses of attaining substantially the same tensile modulus in both the propylene-HAO and propylene- ethylene copolymers.
• Possible blend materials may include, but are not limited to; ethylene copolymers of ethylenically unsaturated esters, polyethylene homopolymers and copolymers with ⁇ -olefins, polypropylene homo and copolymers, ethylene propylene rubbers (EP), ethylene, propylene, diene monomer elastomers (EPDM), styrene-butadiene-styrene (SBS), additives such as slip agents, anti-static agents, colorants, anti-oxidants, stabilizers, fillers, and reinforcers such as CaCO 3 , talc, and glass fiber, and other additives that will be well known to those of ordinary skill in the art.
• EP ethylene propylene rubbers
• EPDM ethylene, propylene, diene monomer elastomers
• SBS styrene-butadiene-styrene
• additives such as slip agents, anti-static agents, colorants, anti-oxidants,
• an R ⁇ of at least 1.1 indicates that an article will exhibit significantly better cold flow resistance than an article made from a propylene-ethylene copolymer.
• the R ⁇ is at least 1.2.
• the R ma is at least 1.3.
• propylene-HAO copolymers exhibit other improved physical properties.
• Table I compares physical properties of propylene copolymers of ethylene and propylene copolymers of
• a silica supported metallocene catalyst is prepared according to the teachings of USSN 07/885,170 using dimethyl silyl, bis(2 methyl, 4,5 benzindenyl) zirconium dichloride as the metallocene.
• the catalyst recipe is 400 grams of silica (Davison 948), 10 grams of metallocene and 3 liters of 10 wt % methyl alumoxane (MAO) in toluene solution as described in OrganoMetallics. v. 13, No. 3, 1994, p.
• Example 2 To the autoclave ofExample 2 is added 550 grams of propylene and 34 grams of hexene- 1. The catalyst ofExample 1 is added (0.2 grams) and the temperature controlled as in Example 2. The reaction is allowed to run for a total of two hours in this case since the relative reactivities of propylene and hexene- 1 are nearly the same under these conditions. A total of 222 grams of propylene- hexene statistical copolymer is obtained. Its weight average molecular weight as measured by size exclusion chromatography is 204,000, its hexene- 1 content is 2.9 wt % (measured by FTIR), and its peak melting point is 126° C.
• Example 2 To the autoclave ofExample 2, 550 grams of propylene is added along with approximately 45 grams of 1-octene as the molar amount ofExample 3. The catalyst ofExample 1 is added and the temperature is controlled as in Example 2.
• a film ofthe copolymer to be characterized is formed by compression molding 9.2 grams ofthe granular copolymer between Mylar® sheets in a form 15 x 15 centimeters in area and 0.5 mm in thickness.
• the molding procedure is: 1) close the platens (controlled at a temperature of 200° C) until they contact the sample; hold for one minute with no applied pressure; 2) increase the clamping force to 10 Tons and hold for one minute; 3) increase the clamping force to 40 tons and hold for two minutes; 4) release the clamping force and quench the film (still between the Mylar sheets) in a water bath at room temperature. After the films are conditioned for six days at room temperature, dumbbell samples are die-cut from the films.
• the tensile properties ofthe resulting samples are measured on a Zwick REL 2051 tensile tester at a temperature of 25 ⁇ 2 degrees C for the standard tensile properties, procedure DIN 53457 (1987) is adhered to.
• the tensile specimen is loaded into the tester just as if one are doing the standard tensile test.
• a predetermined load is applied and the specimen elongation is recorded as a function of time.
• the load is chosen to be in the range of 50-60% of that which would cause the specimens to experience yielding (for samples presented here, a load of 11.7 MPa is chosen).
• the tensile properties of parts made from the resins of examples 2-4 are measured on a tensile tester at a temperature of 25 ⁇ 2 degrees C for the standard tensile properties.
• the tensile specimen is loaded into the tester just as if one are doing the standard tensile test.
• a predetermined load is applied and the specimen elongation is recorded as a function of time.
• the same load is chosen for both parts to be tested, per the definition of R ⁇ , where the two parts have substantially the same modulus.
• the sample elongation recorded 480 seconds after the load is initially applied is chosen as a measure of cold flow for the particular load and this strain divided by the stress applied is designated "the time-delayed compliance".

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Crystallography & Structural Chemistry (AREA)
• Manufacture Of Macromolecular Shaped Articles (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
• Extrusion Moulding Of Plastics Or The Like (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=24258238

Family Applications (1)

Country Status (8)

Families Citing this family (75)

Family Cites Families (3)

• 1996
  • 1996-12-02 JP JP9520736A patent/JP2000501140A/ja active Pending
  • 1996-12-02 WO PCT/US1996/019184 patent/WO1997019991A1/en not_active Application Discontinuation
  • 1996-12-02 KR KR1019980704035A patent/KR19990071757A/ko not_active Application Discontinuation
  • 1996-12-02 CA CA002234108A patent/CA2234108A1/en not_active Abandoned
  • 1996-12-02 BR BR9611669A patent/BR9611669A/pt not_active Application Discontinuation
  • 1996-12-02 EP EP96942122A patent/EP0863943A1/en not_active Withdrawn
  • 1996-12-02 CN CN96198708A patent/CN1203614A/zh active Pending
• 1998
  • 1998-05-27 MX MX9804215A patent/MX9804215A/es unknown

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events