CA1189223A - Polyolefin powder compositions, in particular polyethylene powder compositions, with improved adhesion, and objects made or to be made of such compositions - Google Patents
Polyolefin powder compositions, in particular polyethylene powder compositions, with improved adhesion, and objects made or to be made of such compositionsInfo
- Publication number
- CA1189223A CA1189223A CA000384899A CA384899A CA1189223A CA 1189223 A CA1189223 A CA 1189223A CA 000384899 A CA000384899 A CA 000384899A CA 384899 A CA384899 A CA 384899A CA 1189223 A CA1189223 A CA 1189223A
- Authority
- CA
- Canada
- Prior art keywords
- polyolefin
- powder
- polyethylene
- weight
- stabilized
- 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.)
- Expired
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Classifications
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- 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
-
- 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
- C08J9/34—Chemical features in the manufacture of articles consisting of a foamed macromolecular core and a macromolecular surface layer having a higher density than the core
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
- B29C44/02—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of definite length, i.e. discrete articles
- B29C44/04—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of definite length, i.e. discrete articles consisting of at least two parts of chemically or physically different materials, e.g. having different densities
- B29C44/0423—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of definite length, i.e. discrete articles consisting of at least two parts of chemically or physically different materials, e.g. having different densities by density separation
- B29C44/043—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of definite length, i.e. discrete articles consisting of at least two parts of chemically or physically different materials, e.g. having different densities by density separation using a rotating mould
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B32/00—Water sports boards; Accessories therefor
- B63B32/57—Boards characterised by the material, e.g. laminated materials
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D123/00—Coating compositions based on homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Coating compositions based on derivatives of such polymers
- C09D123/02—Coating compositions based on homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Coating compositions based on derivatives of such polymers not modified by chemical after-treatment
- C09D123/04—Homopolymers or copolymers of ethene
- C09D123/06—Polyethene
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- 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
- C08J2375/00—Characterised by the use of polyureas or polyurethanes; Derivatives of such polymers
- C08J2375/04—Polyurethanes
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- 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
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/249921—Web or sheet containing structurally defined element or component
- Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
- Y10T428/249987—With nonvoid component of specified composition
-
- 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
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/249921—Web or sheet containing structurally defined element or component
- Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
- Y10T428/249987—With nonvoid component of specified composition
- Y10T428/249988—Of about the same composition as, and adjacent to, the void-containing component
- Y10T428/249989—Integrally formed skin
Abstract
ABSTRACT
A polyolefin composition having improved adhesion to foamable plastic substrates, comprising an intimate mixture of about 20% to about 99.5% by weight of a first stabilized polyolefin powder and from about 0.5% to about 80% by weight of a second at most slightly stabilized polyolefin powder, said second powder having a crystalline melting point which is at least 1° higher than that of said first powder and wherein said second powder has the ability to be oxidized under process conditions.
A polyolefin composition having improved adhesion to foamable plastic substrates, comprising an intimate mixture of about 20% to about 99.5% by weight of a first stabilized polyolefin powder and from about 0.5% to about 80% by weight of a second at most slightly stabilized polyolefin powder, said second powder having a crystalline melting point which is at least 1° higher than that of said first powder and wherein said second powder has the ability to be oxidized under process conditions.
Description
POLYOLEFIN POWDER COMPOSITIONS, IN
PARTICULAR POLYETHYLENE POWDER COMPOSITIONS, WITH IMPROVED ADHESION, AND OBJECTS MADE
OR TO BE MADE OF SUCK COMPOSITIONS
BACRGROUND AND SUMMARY OF THE INVENTIOM
.
The invention relates to compositions of polyolefin powders, in particular polyethylene powders, having improved adhesion to substrates and to objects having outer coatings made from such compositions.
Polyolefin plastics are more or less inert because of their structure. Polyolefins, such as polyethylene and polypropylene, are now produced on a very large scale. Polyethylene is generally more inert than polypropylene. Therefore polyethylene is difficult or impossible to bond to RubstratesO It hardly adheres or does not adhere a all to substrates, such as metal surfaces, foamed plastics or the like. To make polyethylene adhere to such a substrate adhesives must be employed, or the surface of the polyethylene and/or the substrate must be etched. however, using adhesives has achieved only a limited degree of adhesion because of the gerlerally poor bonding properties of polyethylene. ~oreaver~
adhesives require extra treatment, which increases the cost and priceO Etching of one or both oE the surfaces to be bonded together is a laborious process, which also lengthens productioQ time and increases the cost price. Similar diEficulties are encountered where polypropyiene is employedO
It is already known that shaped objects can be made from plastics by heating powders in a moldO
the powder melts on the hot wall and orms a layer.
The surfaces of the objects to be made may be thus I, formed by a single layer or by several layers. Foam structures in between layers or against a layer may also be employed Jo improve insulating properties or to limit the combined weight ox the shaped objects.
The surface layer and the foamed or unfoamed layer in contact therewith should, of course, adhere to each otherO however, particularly with polyethylene the present levels of adhesion leave much to be desired.
The same holds true for polypropylene as well.
This problem has been encountered particularly in the manu~ac~ure of surfboards, which are mostly made by rotational molding to form an outer w 11 of polyethyleneO In particular, poly~-thylene having high or medium density, ire. a density of at least 0O930 g/ml has been employed wherein. It ;s also possible Jo use lower density polyethylene. A polyurethene foam Bills the interior space defined by the surface layers or wall formed on the mold surface.
During use, however the outer polyethylene outer wall may be damaged. Water can when penetrate into the foam itself. I there is good adhesion between the outer wall and foam when damage is less llkely to occur. In this latter case wear can penetrate into the foam only under the damaged spot, whereas if adhesion i5 poor, water can be distributed between the wall and foam and can thus be absorbed by all of the foam. Good adhesion between the outer polyethylene skin layer and the polyurethane cover is highly desirable for surfboard in particular, but is also important or other objects built up of similar components. Consequently, where remains a definite need for good adhesion.
.S. Patent No. 3,639,189 proposes to improve the adhesion of polyethylene Jo metal substrates by blending the polyethylene with oxidized polyethylene.
PARTICULAR POLYETHYLENE POWDER COMPOSITIONS, WITH IMPROVED ADHESION, AND OBJECTS MADE
OR TO BE MADE OF SUCK COMPOSITIONS
BACRGROUND AND SUMMARY OF THE INVENTIOM
.
The invention relates to compositions of polyolefin powders, in particular polyethylene powders, having improved adhesion to substrates and to objects having outer coatings made from such compositions.
Polyolefin plastics are more or less inert because of their structure. Polyolefins, such as polyethylene and polypropylene, are now produced on a very large scale. Polyethylene is generally more inert than polypropylene. Therefore polyethylene is difficult or impossible to bond to RubstratesO It hardly adheres or does not adhere a all to substrates, such as metal surfaces, foamed plastics or the like. To make polyethylene adhere to such a substrate adhesives must be employed, or the surface of the polyethylene and/or the substrate must be etched. however, using adhesives has achieved only a limited degree of adhesion because of the gerlerally poor bonding properties of polyethylene. ~oreaver~
adhesives require extra treatment, which increases the cost and priceO Etching of one or both oE the surfaces to be bonded together is a laborious process, which also lengthens productioQ time and increases the cost price. Similar diEficulties are encountered where polypropyiene is employedO
It is already known that shaped objects can be made from plastics by heating powders in a moldO
the powder melts on the hot wall and orms a layer.
The surfaces of the objects to be made may be thus I, formed by a single layer or by several layers. Foam structures in between layers or against a layer may also be employed Jo improve insulating properties or to limit the combined weight ox the shaped objects.
The surface layer and the foamed or unfoamed layer in contact therewith should, of course, adhere to each otherO however, particularly with polyethylene the present levels of adhesion leave much to be desired.
The same holds true for polypropylene as well.
This problem has been encountered particularly in the manu~ac~ure of surfboards, which are mostly made by rotational molding to form an outer w 11 of polyethyleneO In particular, poly~-thylene having high or medium density, ire. a density of at least 0O930 g/ml has been employed wherein. It ;s also possible Jo use lower density polyethylene. A polyurethene foam Bills the interior space defined by the surface layers or wall formed on the mold surface.
During use, however the outer polyethylene outer wall may be damaged. Water can when penetrate into the foam itself. I there is good adhesion between the outer wall and foam when damage is less llkely to occur. In this latter case wear can penetrate into the foam only under the damaged spot, whereas if adhesion i5 poor, water can be distributed between the wall and foam and can thus be absorbed by all of the foam. Good adhesion between the outer polyethylene skin layer and the polyurethane cover is highly desirable for surfboard in particular, but is also important or other objects built up of similar components. Consequently, where remains a definite need for good adhesion.
.S. Patent No. 3,639,189 proposes to improve the adhesion of polyethylene Jo metal substrates by blending the polyethylene with oxidized polyethylene.
2~3 The oxidized polyethylene is obtained by heating polyethylene in an oxygen atmosphere at temperatures that may range from about 90C up to the crystalline melting point of the polyethylene until the desired degree of oxidation has been a~ained. Next, the unoxidized polyethylene is melt-blended with the oxidized polyethylene, and the mixture is then granulated. The thus obtained granulate is used Jo - form the layers on a metal substrate by method mentioned above however; polyethylene oxidation is a laborious process and increases the cost and eventual price of the composition employed as a starting material to produce coated polyethylene shaped objectsO
lS A composition of this kind is also undesired in the manufacture of surfboards, for example, because oxidized polyethylene lowers the resistance of the polyethylene composition to atmospheric inEluences.
Notably the resistance thereof Jo thermal and oxida-tive attack is lowered. In particular, this is highly undesirable for an outer wall 9 such as the poly ethylene coating or a surfboard, which is exposed to outdoor atmospheric influences. This drawback might be overcome by introducing more stabilizer addî~ives ~5 in the polyethylene composition employed. HoweYer, adding stabilizer also increases the cost and priceO
Moreover, compositions contaîning oxidized polyethylene when used to manufacture objects in a mold by, for instance, rotational molding, have another disadvantage. These compositions strongly adhere to the mold surface itself which makes it difficult to remove the finished article Even if a non-oxidized polyethylene is used, it is still necessary to apply release agents in order to facilitate the release of the polyethylene object from the mold. When oxidized polyethylene is used difficulties are still encountered in removing the object from the mold even if release agents are employed.
It has already been attempted to improve properties as well as adhesion by applying a cross-linked polyolefin, by preference a cross-linked polyethylene, or by cross-linking the polyethylene after it has been formed into a surface layer.
Improved adhesion proved to be possible, but a disadvantage remained. Damage to the surface layer remained difficult or impossible to repair n It has now been wound according to one aspect of the present invention that improved adhesion of polyoleEins, in particular polyethylene, to another plastic substrate, such as polyurethane foam, can be achieved without polyethylene or another polyolefin strongly adhering to the mold wall during the molding process by using a polyolefin composition having about 20% to about 99.5% by weight of a s-tabilized polyolefin powder and about 0.5% to about 80% by weight of an unstabilized or hardly stabilized polyolefin powder having a crystalline meting point that is at least 1C higher than that of the stabllizecl polyoLe~:in.
By preference the crystalline melting point of the uns-tabilized or hardly stabilized component is at least C higher than -that of the stabilized component. At the same time adherence of the polyolefin to the mold surface during the molding operation is substantially reduced.
According to a further aspect of the present invention there is provided in a rotational molding process for preparing internally foamed plastic objects coated with an outer polyolefin layer defining an enclosed volume, including first preparing said polyolefin layer in a rotational mold, and thereafter introducing a foamable plastic into the enclosed volume defined by said polyolefin layer and foaming said plast.ic, the improvement consisting essentially of using in combination wi-th the aforesaid steps: a polyolefin having a composition comprising an intimate admixture of about 20% to about 99.5% by weight of a first unstabilized polyolefin powder and about 0.5% to about 80% by weight of a second polyolefin powder having a crystalline melting point which is at least 1C higher than that of said first stabilized polyolefin, and employing process conditions wherein said second polyolefin powder is oxidized.
DETAILED DESCRIPTION
.
The composition provided according to the present invention comprises a stabilized and an - 4a -., ,~ " .
2~
unstabilized component where the unstabilized component is capable of forming oxidized groups, such as C=O, during processing These compositions are particularly suitable for rotational molding, as will be explained with reference to this technique.
however, the possible applications of the compositions of the present invention are not restricted to rotational molding. Damage to the surface layers made from the composition according to the invention can be easily repaired by melt-welding.
So-called rotational molding is a proeedure in which a quantity of a synthetic ~hermoplas~i~ is introduced into a mold which can rotate and/or at least rock back and forth about one or more axes. The mold is meanwhile heated Jo above the melting point of the plastic, and the rotational or rocking motion evenly distributes the powder over the mold surface.
If so desired t by introducing another quantity of the same or a different plastic or plastic composition into the mold, a number of layers can be formedO. The interior space deined by the plastic wall, as formed in one or more layers against the mold wall, can then be illed with a suitable foam such as polyurethane foamO The foam should adhere to khe adjacent polyolefin layer, but the complete object should also be readily released rom the mold at the end of the molding process. The compositions provided according to this invention satisfy thesA
requirements.
The polyolefin compositions according to the present invention are, by preference, polyethylene compositions, Compositions of polyethylene with unstabilized or slightly stabilized polypropylene or polypropylene compositions can also be used. Of the other olefin polymers, only the polyisobutylenes have .
present commercial importance. These elastomers, mostly marketed i.n a modified form, are mainly used in other fields. Further, limited amounts of polybutylene and poly~4-methylpentene-1 are sold on the market. however, use of these polymers are also encompassed my the invention.
In addition to homopolymers, many copolymers are produced. The extent to which these are suitable for rotational molding depends on their composition It is possible, for instance in the case oE poly-ethylene Jo lower the melting point by copolymerizing ethylene w;th small amounts of one or more other oleins. As the components of a composition, therefore, the stabilized component is preferably a copolymer of ethylene, whereas the non-stabilized component is preferably a homopolymer or a copolymer of ethylene with a lower comonomer content, so that its crystalline melting point is at least about 1C
and preferably at least about 4C highe-r than what of the stabilized component.
The invention will be further elucidated and described with reference to polyethylene but as appears from the foregoing it i5 not restricted to the use of this parkicular polyolefin.
Polyethylene is generally mariceted in a granular form. For applications such as rotational molding, polyethylene has to be used in powder form however, the useful particle size of such powders is below about 2 mm, preerably below about 1 mm~ More particularly such powders have a partîcle size in the order of about 0.5 mm~ that is 0O3 mm Jo about 0.6 mmO In most cases the powders are prepared by grinding of a granulate. Polyethylene is also directly available in the form of a powder if the polymerization is carried out in a so called .
9'~ 3 suspension process or a gas-phase process. ~owe~er, the morphological and rheological properties of the polyethylene powders so obtained are generally poor Therefore polyethylenes are usually first granulated and then ground.
The polyethylene processing, in particular high-densi~y polyethylene, wakes place at temperatures above about 140C~ For this reason the granulate is stabilized Jo protect against thermal breakdown. The polyethylene is also stabilized to proteat against oxiaative attack and from the influence of light9 in particular UV radiation. The polyethylene is stabilized in order Jo make objects formed from such a polyethylene resistant to atmospheric influences.
Stabilization against oxidative modification is also necessary to prevent rapid degradative attack when the polymer comes into contact with oxygen, e.g. oxygen in the air duriny processing. In many cases small amounts of stabilizers for providing protection from thermal and oxidative modification are added after polymerization to protect the polymer during further processing.
During the granulation at the end oE the processing operation, further amounts o stab.ilL~ers are added. I this addition is omitted, a non-stabilized or only slightly stabilized polyethylene is obtained, that is a polymer contain;ng less than 0~01 by weight more particularly less than 0.005~ by weight stabiliziny agentsO
Now if such a stabilized polyethylene is usea to make shaped objects in a mold, for instance by rotational molding, oxida~ive modifications will ocrur wherever the polyethylene contacts air at elevated temperature. In most cases air is present in thy moldO When the mold is heated this will result in a noticeable oxidative modification of the polyethylene, such as oxidation, whether or not accompanied by chain break-down, cross-linking, e~c. This gives the polyethylene improved adhesion.
The presence of stabilizers results in the polyethylene being left unoxidized or almost unnotice-ably oxidized under processing conditions. The effect of the invention is brought about by the presence of oxidized groups in the polyethylene, which groups should be capable of forming in the unstabilized com-ponent during processing. This can easily be demon-strated by means of infra-red analysisO It can also.
be establishea unequivocally by forming each component separately into a layer under the normal processing conditio~st and then subjecting these layers Jo infra-red analysis. The unstabilized or slightly stabilizPd polyethylene then shows a clearly qisible band at 1650-1800 cm~l, which is indicative of C=O bonds. If it is to keep its good mechanical properties, the stabilized polyethylene should not9 or at most hardly at all,O exhibit such a band.
If a polyurethane foam is introduced onto a skin made of an unstabilized or little stabillzed polyethylene, adhes:ion it now found Jo be so s-~rong that attempts to sever the polyethylene from the poly-urethane foam results in rupturing of the oam. The rupture does not occur at the boundary between the surface layer and the foam. An unstabilized or slightly stabilized polyethylene adheres strongly to the polyurethane foam or to other substrates.
~owever9 formed from unstabilized or slightly stabilized polyethylene, such a layer has insufficient resistance to atmospheric influences, so that objects made therefrom will weather and deteriorate in an unacceptably short timeO In addition, such a layer adheres to the mold walll Even if release agents are used, it proves difficult to remove the object from the mold.
The use of the compositions according to the present invention results in good adhesion to the substrate, while retaining easy releasability prom the mold wall. A coating made of the compositions according to the present invention is also resistant to weathering Although not intending to be bound thereby it is assumed ha if a polyethylene composition according Jo the invention it made into a layer or a wall for instance by rotational molding, the thin section of what layer in direct con~ac~ with the mold wall is largely or even completely of the stabilized polyethylene. During molding little or no oxidation of the stabilized polyethylene has occurred When the wall is heated the stabilized component which has a lower crystalline melting point than the unstabilized or slightly stabilized component will start to welt first and thereby form an initial very thin layer of stabilized polyethylene in contact with the mold wall. The particles of the unstabilized component, which have a hlgher melting point may stick to the melting stabilized component particles and then melt in their turn as the temperature r;ses further. Thus any actual separation between stabilized and unstabil-ized polyethylene may at best be incomplete ~owever~
the formation o the very thin external layer consisting almost entirely o stabili2ed polyethylene already ensures that the desired surace layer characteristics will be obtained. The unstabilized or hardly stabilized polyethylene will be sligh~y oxidized. This oxidized polyethylene is in contact with the inner surface of the first-formed layer, which has been in.contact with air at elevated temperature for the longest time This surface will now show good adhesion to substrates to which it is appliedO
Infra-red analysis of a layer made by rotational molding of a composition according to the present invention very clearly showed the presence of C=O groups on the inner or interior side of the wall. this was revealed by the occurrence o a band at 1650-1800 cm~l, whereas the outer side of the wall did not show such a band at 1650-1800 cm 1. It may therefore be concluded that the inner wall has been oxidized, whereas the outer or externaI Hall shows an almost insiynifican~ degree of oxidation. Of course, some oxidation of the outer wall cannot be completely prevented in every case. In some cases this results in the occurrence of a very weak band a 16~-1800 cm~l. Although a small degree of oxidation is permis Bible, it should be avoided or kept as limited as possible.
When a compo~i~ion according to this inven-tion it subjected to rotational molding it is necessary on the one hand that such a clegree of oxidation occurs as will ensure good adhesion to the substrate On the other hand it is necessary that the oxidation is not carried so far that release prom the mold can give rise to difficulties, and/or that stabilization can present problems. these are the points which have to be taken into account when deciding how much o the unstabilized component will be usedO Less than about 0~5% by weight of the unstabilized comp3nent has hardly any effect at all and over about 80~ by weight of the unstabilized component is likewise undesirableO By preference the compositions according to the invention contain about 10~ to about 30% by weight of unstabilized polyolefin, in particular about 10% to about 30~ by weight unstabilized or slightly stabilized polyethylene. By preference the stabilized component is a polyethylene copolymer having a minor quantity ox another olefin other than ethylene.
During the processing ox a composition according to the present invention, for instance by rotational molding, migration of stabilizing agents occurs. Insofar as this does not already result in a -homogeneousdistrib~tion~, such distribution will be reached in the course of time as migration con-tinues, albeit slo~ly~ at ambient temperature.
The layer of polyethylene will then end up being uniformly . 15 stabilized and resistant to-a-~mospheric influences.
If this situation is to be reached, it is, of course, necessary that the polye-thylene composition should contain a sufficient quantity of stabilizing agents.
This has to be taken into account in the preparation o the components In general, stabilized polyethylene contains at Ieast about 0.01~ by weight of stabilizlng agents, and in most cases totals at least about 0.025~ by weight of stabilizing agents. The amounts ox stabilizing agents incorporated in the polyethylene are determined by the stability desired. In mos-t cases more than one stay zing agent is addecl because stabilization against varous effects is desired. Also -many combinations of stabilizing agents bring synergetic effects.
There are many commercially available stabilizers.
Any person being skilled in the art can make a proper selection thereof, and that is very well known in the art.
Wast stabilizers is ware) selected in the present compositions is immaterial. The advantages of the present invention are due to the different amounts of stabilizes in the outer- and in the inner layer of the polyethylene skin and not to the particular stabilizers used Like most macromolecular substances, poly-ethylene has no sharply defined melting point. By means of Differential Scanning Calorimetry (indicated by DSC) a temperature-enthalpy curve is obtained. In the so~called melting of polyethylene a DSC curve with a distinct peak is obtained. The~-temperature at which the maximum in the melting Lange occurs with a heating rate of 5C~min can be designated as called the crystalline melting point.
Each component in the compositions according to:the invention may itself be composed ox two or more poIyolefins. For polyethylene compositions use may be made of low-density as well as ox high-densi-ty material, but polyethylene with a density of at least about 0'930 g/ml is generally preferred. Low-density polyethylene has a considerably lower melting point thàn high-density polyethylene. The melting range ox low-density`polyethylene usually runs from abou-t 108C
to about 112C, whereas high-density polyethylene 30 (homopolymer~ melts about from 131C to about 137C.
Copolymers have a lower density value and a lower melting point.
The compositions according to the invention, and notably the components of which they are made up, may contain the normally used additives, such as colorants, fillers and the like.
The invention will now be further elucidated and illustrated in the following non-limit.ing examples.
Example 1 80 parts by weight of a powdery polyethylene having a melt index ~ASTM D 1238v condition of 4~5, a density of 0.93B g/ml, and a mean particle size of 450 ~m~ which had been stabilized with 0.25~ by.weight 2-hydroxy-4~n-octyloxy-benzophenone ~UV stabilizer) - and 0.05~ by weight octadecyl~3-(3,5~di-tert.butyl-4 hydroxyphenyl)propionate (thermal stabilizer an anti-oxidant3 was mixed with 20 parts wt~ of a second pow-dery polyethylene having a melt index of 8, a density of 0~963 g/ml, and a mean particle size of 450 ~m~
which contained only 0O004% by weight of the oc~adecyl-3-(3,5-di-tert.butyl-4 hydroxyphenyl)-propionate. The second component will hereinafter be referred to as the unstabilized component. The crystalline melting temperature o the stabilized component (peak temperature in DSC, heating rate 5C/min~ was 1~6C9 while thaw of the unstabilized component 133C.
A hollow shape was produced from the thoroughly mixed product by rotational molding. The maximum mold temperature was about 275C, the rotation time was 15 mint Next, polyurethane was foamed inside the hollow shape and allowed to cure. The resulting .
2~3 object was readily released from the mold. There-after, sections having a surface area of 5 x 6 cm were cut from the resultant object, so that blocks of polyurethane foam covered with a polyethylene coating on two sides were obtained. These blocks were subjected to a tensile test in which an elongation rate of 1 cm/min was applied.
The strength of the bond between the poly-ethylene and the polyurethane could not be esta-blished, since the polyurethane from itself rupturedfirst. however the bond was at least 0.26~ N/mm2.
Comparative Example A
Example I was repeated but using only khe stabilized componentO Determination of the bondlng strength presented difficulties since the polyethylene coating already began to come loose when the polyurethane roam blocks were being clamped in the machine. In the tensile test the polyethylene layer separated completely from the foam structure before even a measurable value could be recorded. The plane of separation was clean, with no polyurethane Eoam adhering to the polyethylene.
Comparative_Exam~le B
Example I was repeated using only the unstabilized component. In this instance, release of the foam filled object from the mold was attended by severe dif~icul~ies, buy was eventually achieved The bond strength between the polyurethane and foam was at least 0.270 ~/mm20 In the tensile test the polyurethane foam ruptured.
xam~le I I
90 parts by weight of powdery polyethylene having a melt index (A~TM D 1~38) of 4.5, a density of 0.938 g/ml, and a mean particle size of 450 ~m~
stabilized with 0~25~ by weight 2-hydroxy-4-n-oc~oxy-benzophenone (W stabilizer) and 0.05% by weight octadecyl-3-(3,5-di-tert.butyl-4-hydroxy-phenyl)propionate (thermal stabil;zer and a oxidant), was mixed with 10 parts by weight of a powdery polypropylene having a melt index (AST~ D-1238, condition L) of 10~ a density of 0~910 g/ml, and a mean particle size of 400 ~m~ which had no been - st~billzed~ The crystalline melting point of the stabilized component was l C and that of tha unstabilized component was~I65C. This mixture was then used to produce a hollow object in the manner described in Example r. Again, release of the object from the mold was easily achieved. In a tensile test, as descr ibed in Example I, ~up~ur ing of the foam occurred when the tensile force increased above 0.260 N/mm2 .
lS A composition of this kind is also undesired in the manufacture of surfboards, for example, because oxidized polyethylene lowers the resistance of the polyethylene composition to atmospheric inEluences.
Notably the resistance thereof Jo thermal and oxida-tive attack is lowered. In particular, this is highly undesirable for an outer wall 9 such as the poly ethylene coating or a surfboard, which is exposed to outdoor atmospheric influences. This drawback might be overcome by introducing more stabilizer addî~ives ~5 in the polyethylene composition employed. HoweYer, adding stabilizer also increases the cost and priceO
Moreover, compositions contaîning oxidized polyethylene when used to manufacture objects in a mold by, for instance, rotational molding, have another disadvantage. These compositions strongly adhere to the mold surface itself which makes it difficult to remove the finished article Even if a non-oxidized polyethylene is used, it is still necessary to apply release agents in order to facilitate the release of the polyethylene object from the mold. When oxidized polyethylene is used difficulties are still encountered in removing the object from the mold even if release agents are employed.
It has already been attempted to improve properties as well as adhesion by applying a cross-linked polyolefin, by preference a cross-linked polyethylene, or by cross-linking the polyethylene after it has been formed into a surface layer.
Improved adhesion proved to be possible, but a disadvantage remained. Damage to the surface layer remained difficult or impossible to repair n It has now been wound according to one aspect of the present invention that improved adhesion of polyoleEins, in particular polyethylene, to another plastic substrate, such as polyurethane foam, can be achieved without polyethylene or another polyolefin strongly adhering to the mold wall during the molding process by using a polyolefin composition having about 20% to about 99.5% by weight of a s-tabilized polyolefin powder and about 0.5% to about 80% by weight of an unstabilized or hardly stabilized polyolefin powder having a crystalline meting point that is at least 1C higher than that of the stabllizecl polyoLe~:in.
By preference the crystalline melting point of the uns-tabilized or hardly stabilized component is at least C higher than -that of the stabilized component. At the same time adherence of the polyolefin to the mold surface during the molding operation is substantially reduced.
According to a further aspect of the present invention there is provided in a rotational molding process for preparing internally foamed plastic objects coated with an outer polyolefin layer defining an enclosed volume, including first preparing said polyolefin layer in a rotational mold, and thereafter introducing a foamable plastic into the enclosed volume defined by said polyolefin layer and foaming said plast.ic, the improvement consisting essentially of using in combination wi-th the aforesaid steps: a polyolefin having a composition comprising an intimate admixture of about 20% to about 99.5% by weight of a first unstabilized polyolefin powder and about 0.5% to about 80% by weight of a second polyolefin powder having a crystalline melting point which is at least 1C higher than that of said first stabilized polyolefin, and employing process conditions wherein said second polyolefin powder is oxidized.
DETAILED DESCRIPTION
.
The composition provided according to the present invention comprises a stabilized and an - 4a -., ,~ " .
2~
unstabilized component where the unstabilized component is capable of forming oxidized groups, such as C=O, during processing These compositions are particularly suitable for rotational molding, as will be explained with reference to this technique.
however, the possible applications of the compositions of the present invention are not restricted to rotational molding. Damage to the surface layers made from the composition according to the invention can be easily repaired by melt-welding.
So-called rotational molding is a proeedure in which a quantity of a synthetic ~hermoplas~i~ is introduced into a mold which can rotate and/or at least rock back and forth about one or more axes. The mold is meanwhile heated Jo above the melting point of the plastic, and the rotational or rocking motion evenly distributes the powder over the mold surface.
If so desired t by introducing another quantity of the same or a different plastic or plastic composition into the mold, a number of layers can be formedO. The interior space deined by the plastic wall, as formed in one or more layers against the mold wall, can then be illed with a suitable foam such as polyurethane foamO The foam should adhere to khe adjacent polyolefin layer, but the complete object should also be readily released rom the mold at the end of the molding process. The compositions provided according to this invention satisfy thesA
requirements.
The polyolefin compositions according to the present invention are, by preference, polyethylene compositions, Compositions of polyethylene with unstabilized or slightly stabilized polypropylene or polypropylene compositions can also be used. Of the other olefin polymers, only the polyisobutylenes have .
present commercial importance. These elastomers, mostly marketed i.n a modified form, are mainly used in other fields. Further, limited amounts of polybutylene and poly~4-methylpentene-1 are sold on the market. however, use of these polymers are also encompassed my the invention.
In addition to homopolymers, many copolymers are produced. The extent to which these are suitable for rotational molding depends on their composition It is possible, for instance in the case oE poly-ethylene Jo lower the melting point by copolymerizing ethylene w;th small amounts of one or more other oleins. As the components of a composition, therefore, the stabilized component is preferably a copolymer of ethylene, whereas the non-stabilized component is preferably a homopolymer or a copolymer of ethylene with a lower comonomer content, so that its crystalline melting point is at least about 1C
and preferably at least about 4C highe-r than what of the stabilized component.
The invention will be further elucidated and described with reference to polyethylene but as appears from the foregoing it i5 not restricted to the use of this parkicular polyolefin.
Polyethylene is generally mariceted in a granular form. For applications such as rotational molding, polyethylene has to be used in powder form however, the useful particle size of such powders is below about 2 mm, preerably below about 1 mm~ More particularly such powders have a partîcle size in the order of about 0.5 mm~ that is 0O3 mm Jo about 0.6 mmO In most cases the powders are prepared by grinding of a granulate. Polyethylene is also directly available in the form of a powder if the polymerization is carried out in a so called .
9'~ 3 suspension process or a gas-phase process. ~owe~er, the morphological and rheological properties of the polyethylene powders so obtained are generally poor Therefore polyethylenes are usually first granulated and then ground.
The polyethylene processing, in particular high-densi~y polyethylene, wakes place at temperatures above about 140C~ For this reason the granulate is stabilized Jo protect against thermal breakdown. The polyethylene is also stabilized to proteat against oxiaative attack and from the influence of light9 in particular UV radiation. The polyethylene is stabilized in order Jo make objects formed from such a polyethylene resistant to atmospheric influences.
Stabilization against oxidative modification is also necessary to prevent rapid degradative attack when the polymer comes into contact with oxygen, e.g. oxygen in the air duriny processing. In many cases small amounts of stabilizers for providing protection from thermal and oxidative modification are added after polymerization to protect the polymer during further processing.
During the granulation at the end oE the processing operation, further amounts o stab.ilL~ers are added. I this addition is omitted, a non-stabilized or only slightly stabilized polyethylene is obtained, that is a polymer contain;ng less than 0~01 by weight more particularly less than 0.005~ by weight stabiliziny agentsO
Now if such a stabilized polyethylene is usea to make shaped objects in a mold, for instance by rotational molding, oxida~ive modifications will ocrur wherever the polyethylene contacts air at elevated temperature. In most cases air is present in thy moldO When the mold is heated this will result in a noticeable oxidative modification of the polyethylene, such as oxidation, whether or not accompanied by chain break-down, cross-linking, e~c. This gives the polyethylene improved adhesion.
The presence of stabilizers results in the polyethylene being left unoxidized or almost unnotice-ably oxidized under processing conditions. The effect of the invention is brought about by the presence of oxidized groups in the polyethylene, which groups should be capable of forming in the unstabilized com-ponent during processing. This can easily be demon-strated by means of infra-red analysisO It can also.
be establishea unequivocally by forming each component separately into a layer under the normal processing conditio~st and then subjecting these layers Jo infra-red analysis. The unstabilized or slightly stabilizPd polyethylene then shows a clearly qisible band at 1650-1800 cm~l, which is indicative of C=O bonds. If it is to keep its good mechanical properties, the stabilized polyethylene should not9 or at most hardly at all,O exhibit such a band.
If a polyurethane foam is introduced onto a skin made of an unstabilized or little stabillzed polyethylene, adhes:ion it now found Jo be so s-~rong that attempts to sever the polyethylene from the poly-urethane foam results in rupturing of the oam. The rupture does not occur at the boundary between the surface layer and the foam. An unstabilized or slightly stabilized polyethylene adheres strongly to the polyurethane foam or to other substrates.
~owever9 formed from unstabilized or slightly stabilized polyethylene, such a layer has insufficient resistance to atmospheric influences, so that objects made therefrom will weather and deteriorate in an unacceptably short timeO In addition, such a layer adheres to the mold walll Even if release agents are used, it proves difficult to remove the object from the mold.
The use of the compositions according to the present invention results in good adhesion to the substrate, while retaining easy releasability prom the mold wall. A coating made of the compositions according to the present invention is also resistant to weathering Although not intending to be bound thereby it is assumed ha if a polyethylene composition according Jo the invention it made into a layer or a wall for instance by rotational molding, the thin section of what layer in direct con~ac~ with the mold wall is largely or even completely of the stabilized polyethylene. During molding little or no oxidation of the stabilized polyethylene has occurred When the wall is heated the stabilized component which has a lower crystalline melting point than the unstabilized or slightly stabilized component will start to welt first and thereby form an initial very thin layer of stabilized polyethylene in contact with the mold wall. The particles of the unstabilized component, which have a hlgher melting point may stick to the melting stabilized component particles and then melt in their turn as the temperature r;ses further. Thus any actual separation between stabilized and unstabil-ized polyethylene may at best be incomplete ~owever~
the formation o the very thin external layer consisting almost entirely o stabili2ed polyethylene already ensures that the desired surace layer characteristics will be obtained. The unstabilized or hardly stabilized polyethylene will be sligh~y oxidized. This oxidized polyethylene is in contact with the inner surface of the first-formed layer, which has been in.contact with air at elevated temperature for the longest time This surface will now show good adhesion to substrates to which it is appliedO
Infra-red analysis of a layer made by rotational molding of a composition according to the present invention very clearly showed the presence of C=O groups on the inner or interior side of the wall. this was revealed by the occurrence o a band at 1650-1800 cm~l, whereas the outer side of the wall did not show such a band at 1650-1800 cm 1. It may therefore be concluded that the inner wall has been oxidized, whereas the outer or externaI Hall shows an almost insiynifican~ degree of oxidation. Of course, some oxidation of the outer wall cannot be completely prevented in every case. In some cases this results in the occurrence of a very weak band a 16~-1800 cm~l. Although a small degree of oxidation is permis Bible, it should be avoided or kept as limited as possible.
When a compo~i~ion according to this inven-tion it subjected to rotational molding it is necessary on the one hand that such a clegree of oxidation occurs as will ensure good adhesion to the substrate On the other hand it is necessary that the oxidation is not carried so far that release prom the mold can give rise to difficulties, and/or that stabilization can present problems. these are the points which have to be taken into account when deciding how much o the unstabilized component will be usedO Less than about 0~5% by weight of the unstabilized comp3nent has hardly any effect at all and over about 80~ by weight of the unstabilized component is likewise undesirableO By preference the compositions according to the invention contain about 10~ to about 30% by weight of unstabilized polyolefin, in particular about 10% to about 30~ by weight unstabilized or slightly stabilized polyethylene. By preference the stabilized component is a polyethylene copolymer having a minor quantity ox another olefin other than ethylene.
During the processing ox a composition according to the present invention, for instance by rotational molding, migration of stabilizing agents occurs. Insofar as this does not already result in a -homogeneousdistrib~tion~, such distribution will be reached in the course of time as migration con-tinues, albeit slo~ly~ at ambient temperature.
The layer of polyethylene will then end up being uniformly . 15 stabilized and resistant to-a-~mospheric influences.
If this situation is to be reached, it is, of course, necessary that the polye-thylene composition should contain a sufficient quantity of stabilizing agents.
This has to be taken into account in the preparation o the components In general, stabilized polyethylene contains at Ieast about 0.01~ by weight of stabilizlng agents, and in most cases totals at least about 0.025~ by weight of stabilizing agents. The amounts ox stabilizing agents incorporated in the polyethylene are determined by the stability desired. In mos-t cases more than one stay zing agent is addecl because stabilization against varous effects is desired. Also -many combinations of stabilizing agents bring synergetic effects.
There are many commercially available stabilizers.
Any person being skilled in the art can make a proper selection thereof, and that is very well known in the art.
Wast stabilizers is ware) selected in the present compositions is immaterial. The advantages of the present invention are due to the different amounts of stabilizes in the outer- and in the inner layer of the polyethylene skin and not to the particular stabilizers used Like most macromolecular substances, poly-ethylene has no sharply defined melting point. By means of Differential Scanning Calorimetry (indicated by DSC) a temperature-enthalpy curve is obtained. In the so~called melting of polyethylene a DSC curve with a distinct peak is obtained. The~-temperature at which the maximum in the melting Lange occurs with a heating rate of 5C~min can be designated as called the crystalline melting point.
Each component in the compositions according to:the invention may itself be composed ox two or more poIyolefins. For polyethylene compositions use may be made of low-density as well as ox high-densi-ty material, but polyethylene with a density of at least about 0'930 g/ml is generally preferred. Low-density polyethylene has a considerably lower melting point thàn high-density polyethylene. The melting range ox low-density`polyethylene usually runs from abou-t 108C
to about 112C, whereas high-density polyethylene 30 (homopolymer~ melts about from 131C to about 137C.
Copolymers have a lower density value and a lower melting point.
The compositions according to the invention, and notably the components of which they are made up, may contain the normally used additives, such as colorants, fillers and the like.
The invention will now be further elucidated and illustrated in the following non-limit.ing examples.
Example 1 80 parts by weight of a powdery polyethylene having a melt index ~ASTM D 1238v condition of 4~5, a density of 0.93B g/ml, and a mean particle size of 450 ~m~ which had been stabilized with 0.25~ by.weight 2-hydroxy-4~n-octyloxy-benzophenone ~UV stabilizer) - and 0.05~ by weight octadecyl~3-(3,5~di-tert.butyl-4 hydroxyphenyl)propionate (thermal stabilizer an anti-oxidant3 was mixed with 20 parts wt~ of a second pow-dery polyethylene having a melt index of 8, a density of 0~963 g/ml, and a mean particle size of 450 ~m~
which contained only 0O004% by weight of the oc~adecyl-3-(3,5-di-tert.butyl-4 hydroxyphenyl)-propionate. The second component will hereinafter be referred to as the unstabilized component. The crystalline melting temperature o the stabilized component (peak temperature in DSC, heating rate 5C/min~ was 1~6C9 while thaw of the unstabilized component 133C.
A hollow shape was produced from the thoroughly mixed product by rotational molding. The maximum mold temperature was about 275C, the rotation time was 15 mint Next, polyurethane was foamed inside the hollow shape and allowed to cure. The resulting .
2~3 object was readily released from the mold. There-after, sections having a surface area of 5 x 6 cm were cut from the resultant object, so that blocks of polyurethane foam covered with a polyethylene coating on two sides were obtained. These blocks were subjected to a tensile test in which an elongation rate of 1 cm/min was applied.
The strength of the bond between the poly-ethylene and the polyurethane could not be esta-blished, since the polyurethane from itself rupturedfirst. however the bond was at least 0.26~ N/mm2.
Comparative Example A
Example I was repeated but using only khe stabilized componentO Determination of the bondlng strength presented difficulties since the polyethylene coating already began to come loose when the polyurethane roam blocks were being clamped in the machine. In the tensile test the polyethylene layer separated completely from the foam structure before even a measurable value could be recorded. The plane of separation was clean, with no polyurethane Eoam adhering to the polyethylene.
Comparative_Exam~le B
Example I was repeated using only the unstabilized component. In this instance, release of the foam filled object from the mold was attended by severe dif~icul~ies, buy was eventually achieved The bond strength between the polyurethane and foam was at least 0.270 ~/mm20 In the tensile test the polyurethane foam ruptured.
xam~le I I
90 parts by weight of powdery polyethylene having a melt index (A~TM D 1~38) of 4.5, a density of 0.938 g/ml, and a mean particle size of 450 ~m~
stabilized with 0~25~ by weight 2-hydroxy-4-n-oc~oxy-benzophenone (W stabilizer) and 0.05% by weight octadecyl-3-(3,5-di-tert.butyl-4-hydroxy-phenyl)propionate (thermal stabil;zer and a oxidant), was mixed with 10 parts by weight of a powdery polypropylene having a melt index (AST~ D-1238, condition L) of 10~ a density of 0~910 g/ml, and a mean particle size of 400 ~m~ which had no been - st~billzed~ The crystalline melting point of the stabilized component was l C and that of tha unstabilized component was~I65C. This mixture was then used to produce a hollow object in the manner described in Example r. Again, release of the object from the mold was easily achieved. In a tensile test, as descr ibed in Example I, ~up~ur ing of the foam occurred when the tensile force increased above 0.260 N/mm2 .
Claims (6)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A polyolefin composition capable of adhesion to a substrate, comprising an intimate mixture of about 20% to about 99.5% by weight of a first stabilized polyolefin powder and from about 0.5% to about 80% by weight of a second, at most slightly stabilized, polyolefin powder, said second powder having a crystalline melting point which is at least 1°C higher than that of said first powder.
2. A polyethylene composition capable of adhesion to a substrate, comprising an intimate mixture of about 20% to about 99.5% by weight of a first stabilized polyethylene powder and to 0.5% to about 80% by weight of a second, at most slightly stabilized, polyethylene powder, said second powder having a crystalline melting point which is at least 4°C higher than that of said first powder.
3. A polyolefin composition according to claim 1 or 2, wherein said composition comprises about 70% to about 90% by weight of said first stabilized polyolefin powder and about 10%
to about 30% by weight of said second, at most slightly stabilized, polyolefin powder.
to about 30% by weight of said second, at most slightly stabilized, polyolefin powder.
4. A polyolefin composition according to claim 1 or 2, wherein said second powder contains at most about 0.01% of a stabilizing agent by weight.
5. A polyolefin composition according to claim 1 or 2, wherein said second powder contains at most about 0.005% of a stabilizing agent by weight.
6. In a rotational molding process for preparing internally foamed plastic objects coated with an outer polyolefin layer defining an enclosed volume, including first preparing said polyolefin layer in a rotational mold, and thereafter introducing a foamable plastic into the enclosed volume defined by said polyolefin layer and foaming said plastic, the improvement consisting essentially of using in combination with the aforesaid steps: a polyolefin having a composition comprising an intimate admixture of about 20% to about 99.5% by weight of a first unstabilized polyolefin powder and about 0.5% to about 80% by weight of a second polyolefin powder having a crystalline melting point which is at least 1°C higher than that of said first stabilized polyolefin, and employing process conditions wherein said second polyolefin powder is oxidized.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL8004958A NL8004958A (en) | 1980-08-30 | 1980-08-30 | POLYOLEFINE POWDER COMPOSITIONS, IN PARTICULAR POLYETHENE POWDER COMPOSITIONS WITH IMPROVED ADHESION AND OF MANUFACTURED AND MANUFACTURED THEREOF. |
| NL8004958 | 1980-08-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1189223A true CA1189223A (en) | 1985-06-18 |
Family
ID=19835806
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000384899A Expired CA1189223A (en) | 1980-08-30 | 1981-08-31 | Polyolefin powder compositions, in particular polyethylene powder compositions, with improved adhesion, and objects made or to be made of such compositions |
Country Status (21)
| Country | Link |
|---|---|
| US (2) | US4440899A (en) |
| EP (1) | EP0047039B1 (en) |
| JP (1) | JPS608253B2 (en) |
| KR (1) | KR840002125B1 (en) |
| AT (1) | ATE14744T1 (en) |
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| CA (1) | CA1189223A (en) |
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| PT (1) | PT73541B (en) |
| YU (1) | YU206881A (en) |
| ZA (1) | ZA815707B (en) |
Families Citing this family (17)
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|---|---|---|---|---|
| EP0087204B1 (en) * | 1982-02-20 | 1988-08-03 | Stamicarbon B.V. | Polymer powder compositions, particularly polyethylene powder compositions, and objects to be made and made thereof |
| JPS5911372A (en) * | 1982-07-08 | 1984-01-20 | Shinto Paint Co Ltd | Coating paint composition |
| JPS5975929A (en) * | 1982-10-25 | 1984-04-28 | Sekisui Chem Co Ltd | Production of polyolefin foam |
| CA1249383A (en) * | 1985-06-27 | 1989-01-24 | Liqui-Box Canada Inc. | Blends of polyolefins with polymers containing reactive agents |
| US4882229A (en) * | 1988-04-29 | 1989-11-21 | Shell Oil Company | Blends of high molecular weight polybutylene with low density polyethylene |
| US5206292A (en) * | 1992-05-28 | 1993-04-27 | Shell Oil Company | Pelletizing aid for manufacturing polyolefins |
| JPH06126755A (en) * | 1992-10-15 | 1994-05-10 | Bridgestone Corp | Method for molding polyurethane sheet pad |
| DE4435124A1 (en) * | 1994-09-30 | 1996-04-04 | Siemens Ag | Electrical and-or optical cable with markings on the sheath |
| GB9818316D0 (en) * | 1998-08-21 | 1998-10-14 | Borealis As | Polymer |
| US6103153A (en) * | 1999-06-02 | 2000-08-15 | Park; Chul B. | Production of foamed low-density polypropylene by rotational molding |
| GB0004043D0 (en) * | 2000-02-21 | 2000-04-12 | Borealis Polymers Oy | Polymer |
| CA2437221C (en) * | 2001-02-05 | 2009-05-05 | 3Dm Technologies, Inc. | Processes for forming plastic, apparatuses for forming plastic, and articles made therefrom |
| US20040075194A1 (en) * | 2002-10-18 | 2004-04-22 | Applied Polymer Sciences Llc | Process for the use of polymeric materials to produce molded foam products |
| US7582238B1 (en) | 2004-01-09 | 2009-09-01 | Yomazzo Michael J | Surfboard |
| EP1600474A1 (en) * | 2004-05-28 | 2005-11-30 | Total Petrochemicals Research Feluy | Use of fluoropolymers for rotomolding |
| SG11201807667TA (en) | 2016-03-18 | 2018-10-30 | Scg Chemicals Co Ltd | Polyolefin composition for rotational molding |
| CA3166167A1 (en) * | 2020-02-17 | 2021-08-26 | Nova Chemicals Corporation | Rotomolding composition |
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| CA714619A (en) * | 1965-07-27 | F. Wissbrun Kurt | Polymer blends | |
| BE524672A (en) * | 1952-11-29 | 1900-01-01 | ||
| US3527667A (en) * | 1962-01-02 | 1970-09-08 | Phillips Petroleum Co | Anti-oxidant free 1-olefin coated metal substrate and method for coating same |
| US3187069A (en) * | 1962-09-28 | 1965-06-01 | Kay Mfg Corp | Making foamed articles |
| US3426110A (en) * | 1965-03-26 | 1969-02-04 | Gen Motors Corp | Refrigerating apparatus |
| US3503922A (en) * | 1965-07-15 | 1970-03-31 | Polymer Dispersions Inc | Process for producing dispersions of finely - divided solids in isotactic polypropylene |
| US3607987A (en) * | 1967-07-20 | 1971-09-21 | Phillips Petroleum Co | Coating composition comprising polyethylene and a visbroken copolymer of ethylene and propylene |
| US3639189A (en) * | 1969-09-09 | 1972-02-01 | Allied Chem | Adhesive compositions comprising polyethylene and oxidized polyethylene |
| US3995984A (en) * | 1972-06-27 | 1976-12-07 | Composite Structures Corporation | Matching dies for composite cored structures |
| IT967401B (en) * | 1972-09-13 | 1974-02-28 | Schmid Charles | PROCEDURE FOR OBTAINING CABLE CYLINDRICAL BODIES WITH SUPPORTING STRUCTURE IN REINFORCED TER-HARDENING RESIN AND CYLINDRICAL CABLE BODY OBTAINED WITH THIS PROCEDURE |
| US4065337A (en) * | 1973-04-18 | 1977-12-27 | Coast Catamaran Corporation | Molding process |
| US3929550A (en) * | 1973-08-27 | 1975-12-30 | Dart Ind Inc | Process for promoting polyolefin adhesion |
| GB1494898A (en) * | 1974-04-22 | 1977-12-14 | Arrow Hart Ltd | Electric switch |
| US3936565A (en) * | 1974-05-03 | 1976-02-03 | Hollowform, Inc. | Molded plastic article and method |
| GB1494897A (en) * | 1975-02-11 | 1977-12-14 | Ac Canoe Prod Ltd | Kayak |
| ATA323275A (en) * | 1975-04-28 | 1976-11-15 | Sempiran Patentverwert | METHOD FOR MANUFACTURING A COMPOSITE BODY AND COMPOSITE BODY MANUFACTURED AFTER THAT |
| DE2529001A1 (en) * | 1975-06-28 | 1977-01-13 | Alfred Boeckmann | SOLAR ENERGY CONVERTER WITH STORAGE FOR THE CONVERTED ENERGY |
| GB1532629A (en) * | 1975-11-11 | 1978-11-15 | Textile Bonding Ltd | Laminated materials |
| FR2344100A1 (en) * | 1976-03-10 | 1977-10-07 | Comp Generale Electricite | INSULATION MATERIAL FOR HIGH VOLTAGE ELECTRIC ENERGY TRANSMISSION CABLE |
| US4104335A (en) * | 1976-09-02 | 1978-08-01 | American Cyanamid Company | Dustless, free-flowing ultraviolet absorbing compositions for polyolefins |
| US4167382A (en) * | 1978-06-12 | 1979-09-11 | Sybron Corporation | Apparatus for roto-molding |
| US4255221A (en) * | 1978-12-08 | 1981-03-10 | Young Gary W | Surfboard and method and apparatus for making surfboards and like molded structures |
| NL7905060A (en) * | 1979-06-29 | 1980-12-31 | Stamicarbon | METHOD FOR APPLYING A POLYMERIC LAYER TO A METAL SURFACE, POLYMER POWDER SUITABLE FOR THIS METHOD AND METAL ARTICLES COATED WITH A POLYMERIC LAYER |
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1980
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1981
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- 1981-08-26 YU YU02068/81A patent/YU206881A/en unknown
- 1981-08-26 MA MA19456A patent/MA19256A1/en unknown
- 1981-08-27 AT AT81200946T patent/ATE14744T1/en not_active IP Right Cessation
- 1981-08-27 EP EP81200946A patent/EP0047039B1/en not_active Expired
- 1981-08-27 DE DE8181200946T patent/DE3171702D1/en not_active Expired
- 1981-08-28 ES ES505040A patent/ES8206594A1/en not_active Expired
- 1981-08-28 NO NO812941A patent/NO160378C/en unknown
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- 1981-08-28 BR BR8105515A patent/BR8105515A/en unknown
- 1981-08-28 DK DK384181A patent/DK157934C/en not_active IP Right Cessation
- 1981-08-28 MX MX819641U patent/MX7352E/en unknown
- 1981-08-31 CA CA000384899A patent/CA1189223A/en not_active Expired
- 1981-08-31 KR KR1019810003200A patent/KR840002125B1/en active
- 1981-08-31 JP JP56136926A patent/JPS608253B2/en not_active Expired
- 1981-08-31 FI FI812681A patent/FI74031C/en not_active IP Right Cessation
- 1981-08-31 US US06/298,253 patent/US4440899A/en not_active Expired - Fee Related
-
1984
- 1984-02-06 US US06/577,335 patent/US4477400A/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| DK384181A (en) | 1982-03-01 |
| ES505040A0 (en) | 1982-08-16 |
| NO812941L (en) | 1982-03-01 |
| PT73541A (en) | 1981-09-01 |
| DK157934B (en) | 1990-03-05 |
| EP0047039A1 (en) | 1982-03-10 |
| NO160378C (en) | 1989-04-12 |
| AU7427181A (en) | 1982-03-11 |
| ATE14744T1 (en) | 1985-08-15 |
| KR830006348A (en) | 1983-09-24 |
| EP0047039B1 (en) | 1985-08-07 |
| US4477400A (en) | 1984-10-16 |
| FI74031B (en) | 1987-08-31 |
| ZA815707B (en) | 1982-08-25 |
| ES8206594A1 (en) | 1982-08-16 |
| KR840002125B1 (en) | 1984-11-19 |
| IL63582A0 (en) | 1981-11-30 |
| YU206881A (en) | 1984-04-30 |
| IE811978L (en) | 1982-02-28 |
| JPS608253B2 (en) | 1985-03-01 |
| US4440899A (en) | 1984-04-03 |
| DE3171702D1 (en) | 1985-09-12 |
| PT73541B (en) | 1982-11-03 |
| MA19256A1 (en) | 1982-04-01 |
| DK157934C (en) | 1990-08-06 |
| FI812681L (en) | 1982-03-01 |
| NO160378B (en) | 1989-01-02 |
| FI74031C (en) | 1987-12-10 |
| IE51761B1 (en) | 1987-03-18 |
| MX7352E (en) | 1988-07-19 |
| JPS5778435A (en) | 1982-05-17 |
| BR8105515A (en) | 1982-05-18 |
| NL8004958A (en) | 1982-04-01 |
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| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |