CA2406263A1 - Plastic granulate - Google Patents
Plastic granulate Download PDFInfo
- Publication number
- CA2406263A1 CA2406263A1 CA002406263A CA2406263A CA2406263A1 CA 2406263 A1 CA2406263 A1 CA 2406263A1 CA 002406263 A CA002406263 A CA 002406263A CA 2406263 A CA2406263 A CA 2406263A CA 2406263 A1 CA2406263 A1 CA 2406263A1
- Authority
- CA
- Canada
- Prior art keywords
- fibres
- granulate
- plastic
- thermoplastic polymer
- bundle
- 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.)
- Abandoned
Links
- 239000008187 granular material Substances 0.000 title claims abstract description 76
- 239000004033 plastic Substances 0.000 title claims abstract description 37
- 229920003023 plastic Polymers 0.000 title claims abstract description 37
- 229920001169 thermoplastic Polymers 0.000 claims abstract description 36
- 238000000034 method Methods 0.000 claims abstract description 27
- 238000000465 moulding Methods 0.000 claims abstract description 23
- 238000002360 preparation method Methods 0.000 claims abstract description 9
- 229920000642 polymer Polymers 0.000 claims description 17
- 239000000835 fiber Substances 0.000 claims description 16
- 239000000155 melt Substances 0.000 claims description 15
- -1 polyethylene Polymers 0.000 claims description 9
- 238000002844 melting Methods 0.000 claims description 8
- 230000008018 melting Effects 0.000 claims description 8
- 229920000098 polyolefin Polymers 0.000 claims description 7
- 238000000354 decomposition reaction Methods 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 6
- 240000000491 Corchorus aestuans Species 0.000 claims description 5
- 235000011777 Corchorus aestuans Nutrition 0.000 claims description 5
- 235000010862 Corchorus capsularis Nutrition 0.000 claims description 5
- 239000004743 Polypropylene Substances 0.000 claims description 5
- 229920001155 polypropylene Polymers 0.000 claims description 5
- 239000004698 Polyethylene Substances 0.000 claims description 4
- 239000003365 glass fiber Substances 0.000 claims description 4
- 229920000573 polyethylene Polymers 0.000 claims description 4
- 244000198134 Agave sisalana Species 0.000 claims description 2
- 244000025254 Cannabis sativa Species 0.000 claims description 2
- 235000012766 Cannabis sativa ssp. sativa var. sativa Nutrition 0.000 claims description 2
- 235000012765 Cannabis sativa ssp. sativa var. spontanea Nutrition 0.000 claims description 2
- 240000000797 Hibiscus cannabinus Species 0.000 claims description 2
- 240000006240 Linum usitatissimum Species 0.000 claims description 2
- 235000004431 Linum usitatissimum Nutrition 0.000 claims description 2
- 235000009120 camo Nutrition 0.000 claims description 2
- 235000005607 chanvre indien Nutrition 0.000 claims description 2
- 239000011487 hemp Substances 0.000 claims description 2
- 230000000052 comparative effect Effects 0.000 description 8
- 238000002474 experimental method Methods 0.000 description 8
- 239000000463 material Substances 0.000 description 7
- 230000015556 catabolic process Effects 0.000 description 6
- 238000006731 degradation reaction Methods 0.000 description 6
- 239000006185 dispersion Substances 0.000 description 6
- 238000012360 testing method Methods 0.000 description 4
- 238000001746 injection moulding Methods 0.000 description 3
- 150000008065 acid anhydrides Chemical class 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000001125 extrusion Methods 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 229920001519 homopolymer Polymers 0.000 description 2
- 238000005470 impregnation Methods 0.000 description 2
- 239000004615 ingredient Substances 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 239000012815 thermoplastic material Substances 0.000 description 2
- 239000004416 thermosoftening plastic Substances 0.000 description 2
- 238000009736 wetting Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229920000742 Cotton Polymers 0.000 description 1
- 239000004594 Masterbatch (MB) Substances 0.000 description 1
- 239000012963 UV stabilizer Substances 0.000 description 1
- 239000003963 antioxidant agent Substances 0.000 description 1
- 239000004760 aramid Substances 0.000 description 1
- 229920003235 aromatic polyamide Polymers 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000003467 diminishing effect Effects 0.000 description 1
- 238000002845 discoloration Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000005445 natural material Substances 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 239000005060 rubber Substances 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 238000004513 sizing Methods 0.000 description 1
- 238000003892 spreading Methods 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
- 238000007669 thermal treatment Methods 0.000 description 1
- 229920002725 thermoplastic elastomer Polymers 0.000 description 1
- 229920001187 thermosetting polymer Polymers 0.000 description 1
- 238000011282 treatment Methods 0.000 description 1
- 235000013311 vegetables Nutrition 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B9/00—Making granules
- B29B9/12—Making granules characterised by structure or composition
- B29B9/14—Making granules characterised by structure or composition fibre-reinforced
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B7/00—Mixing; Kneading
- B29B7/30—Mixing; Kneading continuous, with mechanical mixing or kneading devices
- B29B7/58—Component parts, details or accessories; Auxiliary operations
- B29B7/72—Measuring, controlling or regulating
- B29B7/726—Measuring properties of mixture, e.g. temperature or density
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B9/00—Making granules
- B29B9/16—Auxiliary treatment of granules
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B7/00—Mixing; Kneading
- B29B7/30—Mixing; Kneading continuous, with mechanical mixing or kneading devices
- B29B7/34—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices
- B29B7/38—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B9/00—Making granules
- B29B9/02—Making granules by dividing preformed material
- B29B9/06—Making granules by dividing preformed material in the form of filamentary material, e.g. combined with extrusion
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2023/00—Use of polyalkenes or derivatives thereof as moulding material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2311/00—Use of natural products or their composites, not provided for in groups B29K2201/00 - B29K2309/00, as reinforcement
- B29K2311/10—Natural fibres, e.g. wool or cotton
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Reinforced Plastic Materials (AREA)
- Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
The invention relates to a plastic granulate on the basis of a thermoplastic polymer and natural fibres. A bundle of the natural fibres, predominantly oriented in the longitudinal direction of the granulate, is provided with a sheath of the thermoplastic polymer. The invention also relates to a process for the preparation of such a granulate, as well as to a moulding made thereof.
Description
_1_ PLASTIC GRANULATE
The invention relates to a plastic granulate on the basis of a thermoplastic polymer and natural fibres. The invention also relates to a process for the preparation of such a granulate, as well as to a moulding made thereof.
Such a granulate is known from EP-A-865,891, which describes how the granulate is obtained by mixing chopped natural fibres with a thermoplastic polymer, followed by production of a granulate. The granulate thus obtained is for instance used as a starting material for mouldings, produced with application of techniques such as injection moulding.
During the preparation of the granulate and in the moulding process the material is brought to a high temperature, i.e. the processing temperature of the thermoplastic polymer, which temperature is mostly 40-100 °C
above the melting temperature of the polymer. During such treatments the natural fibres are also exposed to these high temperatures. At those temperatures the natural fibres are exposed to a high thermal and mechanical burden, which results in degradation and decomposition of the fibres and thus ultimately loss of the properties of the moulding.
The aim of the invention is a plastic granulate on the basis of a thermoplastic polymer and natural fibres, obtained with much less thermal and mechanical burdening of the natural fibres, due to which the formation of a moulding from such a granulate gives an object having improved properties.
The plastic granulate according to the invention is characterized in that the granulate comprises a bundle of natural fibres, predominantly oriented in the longitudinal direction of the granulate, the bundle being provided with a sheath of the thermoplastic polymer and the fibre bundle being as long or virtually as long as the granulate, and wherein the decomposition temperature of the natural fibres is 20 to 80 °C higher than the melting point of the thermoplastic polymer.
The granulate according to the invention thus contains a bundle of natural fibres (in the following also referred to as 'rope') provided with a sheath made of a thermoplastic polymer. The type of rope as such is not really relevant to the invention, much less than the fact that the rope is provided with a sheath, i.e.
the outer surface of the rope is sheathed with the thermoplastic polymer. The thermoplastic polymer can at most be partially present between the fibres of the
The invention relates to a plastic granulate on the basis of a thermoplastic polymer and natural fibres. The invention also relates to a process for the preparation of such a granulate, as well as to a moulding made thereof.
Such a granulate is known from EP-A-865,891, which describes how the granulate is obtained by mixing chopped natural fibres with a thermoplastic polymer, followed by production of a granulate. The granulate thus obtained is for instance used as a starting material for mouldings, produced with application of techniques such as injection moulding.
During the preparation of the granulate and in the moulding process the material is brought to a high temperature, i.e. the processing temperature of the thermoplastic polymer, which temperature is mostly 40-100 °C
above the melting temperature of the polymer. During such treatments the natural fibres are also exposed to these high temperatures. At those temperatures the natural fibres are exposed to a high thermal and mechanical burden, which results in degradation and decomposition of the fibres and thus ultimately loss of the properties of the moulding.
The aim of the invention is a plastic granulate on the basis of a thermoplastic polymer and natural fibres, obtained with much less thermal and mechanical burdening of the natural fibres, due to which the formation of a moulding from such a granulate gives an object having improved properties.
The plastic granulate according to the invention is characterized in that the granulate comprises a bundle of natural fibres, predominantly oriented in the longitudinal direction of the granulate, the bundle being provided with a sheath of the thermoplastic polymer and the fibre bundle being as long or virtually as long as the granulate, and wherein the decomposition temperature of the natural fibres is 20 to 80 °C higher than the melting point of the thermoplastic polymer.
The granulate according to the invention thus contains a bundle of natural fibres (in the following also referred to as 'rope') provided with a sheath made of a thermoplastic polymer. The type of rope as such is not really relevant to the invention, much less than the fact that the rope is provided with a sheath, i.e.
the outer surface of the rope is sheathed with the thermoplastic polymer. The thermoplastic polymer can at most be partially present between the fibres of the
-2-rope, i.e. there is no full impregnation of the rope. The fact is that the characteristic feature of the invention is that during the preparation of the granulate the fibre bundle as a whole, i.e. the rope, is only subjected virtually exclusively to a thermal treatment for a relatively short time, while in the case of full impregnation (like in the prior art) this thermal effect affects every fibre of the bundle, resulting in much more fibre degradation. The fibres in the granulate according to the invention thus preserve their original properties to a high extent or even completely.
The fibre material used for the rope present in the granulate according to the invention can be any natural material, of vegetable as well as animal origin. The fibre material is preferably selected from the group comprising jute, flax, kenaf, sisal and hemp fibres, but cotton and silk fibres are also quite suitable. Mixtures of two or more of these fibres can also be present, either in one mixed rope, or in the form of separate ropes.
The granulate can also comprise a mixture of natural and other fibres. The latter can be for instance plastic fibres (such as polyolefin, aramid or polyester fibres), inorganic fibres (such as glass or metal fibres) or carbon fibres.
Preferably, as 'other fibres', plastic fibres and/or glass fibres are used.
Such other fibres can be present in one mixed rope together with the natural fibres, but also be present separately in the plastic granulate.
The fibres can optionally be provided with an oil or with a sizing, in combination with an adhesion improvement agent if required. These agents, which are known per se to the person skilled in the art, promote the dispersion in and/or the adhesion of the fibres to the thermoplast of the moulding to be produced ultimately.
For a plastic granulate according to the invention it is important that the difference between on the one hand the temperature at which the natural fibres begin to degrade or decompose significantly and on the other hand the melting point of the thermoplastic polymer is sufficiently large. The decomposition temperature of the natural fibres must therefore be 20 to 80 °C, preferably 35-70 °C, higher than the melting point of the thermoplastic polymer.
A suitable thermoplastic material for the plastic granulate of the invention is in principle any thermoplastic polymer which satisfies the above-mentioned condition concerning the melting point in relation with the decomposition temperature of the natural fibre. Particularly suitable are polyolefins
The fibre material used for the rope present in the granulate according to the invention can be any natural material, of vegetable as well as animal origin. The fibre material is preferably selected from the group comprising jute, flax, kenaf, sisal and hemp fibres, but cotton and silk fibres are also quite suitable. Mixtures of two or more of these fibres can also be present, either in one mixed rope, or in the form of separate ropes.
The granulate can also comprise a mixture of natural and other fibres. The latter can be for instance plastic fibres (such as polyolefin, aramid or polyester fibres), inorganic fibres (such as glass or metal fibres) or carbon fibres.
Preferably, as 'other fibres', plastic fibres and/or glass fibres are used.
Such other fibres can be present in one mixed rope together with the natural fibres, but also be present separately in the plastic granulate.
The fibres can optionally be provided with an oil or with a sizing, in combination with an adhesion improvement agent if required. These agents, which are known per se to the person skilled in the art, promote the dispersion in and/or the adhesion of the fibres to the thermoplast of the moulding to be produced ultimately.
For a plastic granulate according to the invention it is important that the difference between on the one hand the temperature at which the natural fibres begin to degrade or decompose significantly and on the other hand the melting point of the thermoplastic polymer is sufficiently large. The decomposition temperature of the natural fibres must therefore be 20 to 80 °C, preferably 35-70 °C, higher than the melting point of the thermoplastic polymer.
A suitable thermoplastic material for the plastic granulate of the invention is in principle any thermoplastic polymer which satisfies the above-mentioned condition concerning the melting point in relation with the decomposition temperature of the natural fibre. Particularly suitable are polyolefins
-3-and polyolefin-based polymer systems (such as blends of a polyolefin and a non-cross-linked or cross-linked rubber, as in a thermoplastic elastomer vulcanizate).
The polyolefin is preferably chosen from the group of polyethylene and polypropylene, both the homopolymers and the copolymers being suitable. A
person skilled in the art is familiar with such materials. Thermosetting materials which are thermoplastic during the preparation of the plastic granulate and are only cured in the final processing stage are also suitable as material for the granulate according to the invention.
The length and the diameter of the granulate are not critical as such. Generally, the length of the granulate is <_ 50 mm, the diameter 5 15 mm.
For practical purposes it is preferred for the granulate to have a length of 5-40 mm and a diameter of 1-10 mm.
The fibre content of the plastic granulate according to the invention can in principle be chosen freely, depending on the further use of the granulate. If the granulate is supplied in the form of a masterbatch, the fibre content will generally be high, while if the granulate is used as such a lower fibre content will mostly be used. On the whole the granulate preferably contains 20-85 wt.% fibres.
Since the fibres are not well dispersed in the granulate and it is mostly a requirement that mouldings made of the granulate do have a good dispersion, it is of advantage if the granulate already has features which will promote said dispersion in the moulding. One such feature is that the rope is a bundle of the natural fibres and readily flowing plastic fibres (i.e. fibres which melt in the moulding process and have a low viscosity then) so that the thermoplastic material spreads well through the fibres.
Another, preferred option is that the sheath of the plastic granulate, viewed from the core of the granulate, consists of a first layer of a low-viscous thermoplastic polymer and a second layer of a high-viscous thermoplastic polymer, the ratio of the melt indices of the two polymers lying between 10 and 100. The melt index of the first layer preferably lies between 50 and 250 and the melt index of the second layer preferably between 0.1 and 25, both values being determined in accordance with ISO 1133. In order to ensure good properties of the moulding ultimately obtained, the thermoplastic polymers are preferably of the same type or compatible with each other.
It should also be ensured, for instance by means of an adhesion
The polyolefin is preferably chosen from the group of polyethylene and polypropylene, both the homopolymers and the copolymers being suitable. A
person skilled in the art is familiar with such materials. Thermosetting materials which are thermoplastic during the preparation of the plastic granulate and are only cured in the final processing stage are also suitable as material for the granulate according to the invention.
The length and the diameter of the granulate are not critical as such. Generally, the length of the granulate is <_ 50 mm, the diameter 5 15 mm.
For practical purposes it is preferred for the granulate to have a length of 5-40 mm and a diameter of 1-10 mm.
The fibre content of the plastic granulate according to the invention can in principle be chosen freely, depending on the further use of the granulate. If the granulate is supplied in the form of a masterbatch, the fibre content will generally be high, while if the granulate is used as such a lower fibre content will mostly be used. On the whole the granulate preferably contains 20-85 wt.% fibres.
Since the fibres are not well dispersed in the granulate and it is mostly a requirement that mouldings made of the granulate do have a good dispersion, it is of advantage if the granulate already has features which will promote said dispersion in the moulding. One such feature is that the rope is a bundle of the natural fibres and readily flowing plastic fibres (i.e. fibres which melt in the moulding process and have a low viscosity then) so that the thermoplastic material spreads well through the fibres.
Another, preferred option is that the sheath of the plastic granulate, viewed from the core of the granulate, consists of a first layer of a low-viscous thermoplastic polymer and a second layer of a high-viscous thermoplastic polymer, the ratio of the melt indices of the two polymers lying between 10 and 100. The melt index of the first layer preferably lies between 50 and 250 and the melt index of the second layer preferably between 0.1 and 25, both values being determined in accordance with ISO 1133. In order to ensure good properties of the moulding ultimately obtained, the thermoplastic polymers are preferably of the same type or compatible with each other.
It should also be ensured, for instance by means of an adhesion
-4-promoter, that in the moulding there is good contact between the original sheath material and the fibres.
The plastic granulate according to the invention can further contain the ingredients that are required for plastic objects, such as antioxidants, UV stabilizers, fillers, colorants, etc. Such ingredients are known to the person skilled in the art.
The invention also relates to a process for the preparation of a plastic granulate as described above. In such a preparation process it is important that the fibres are supplied in such a form that in the sheathing procedure a granulate is obtained in which the fibres are predominantly oriented in the longitudinal direction of the granulate. To that end the fibres should be combined to form one or more continuous bundles or ropes. The manufacture of such a bundle or rope as such is known to the person skilled in the art. The ropes can be of a single natural or of another fibre, they can also be a mixture of natural fibres, a mixture of one or more natural fibres with other fibres, etc.
The process according to the invention is characterized in that one or more continuous bundles of the natural fibres, optionally mixed or jointed with other fibres, is sheathed with a melt of the thermoplastic polymer, after which the product obtained (the extrudate) is cooled and cut up to the desired length. In this process use can be made of sheathing techniques known per se, such as for the sheathing of glass or metal fibres. For this purpose the thermoplastic polymer is heated, using an extruder for instance, to a temperature above the melting point and as such supplied to the sheathing apparatus.
In the process according to the invention the continuous bundles) of (natural) fibres is preferably sheathed in a first step with a low-viscous thermoplastic polymer and subsequently or simultaneously with a high-viscous polymer, with the ratio of the melt indices of the two polymers lying between and 100.
The melt index of the low-viscous thermoplastic polymer preferably lies between 50 and 250, while the melt index of the high-viscous thermoplastic polymer lies between 0.1 and 25, both measured according to ISO 1133.
The residence time, in particular that of the natural fibres, during the sheathing process is relatively short, without the occurrence of mechanical degradation of these fibres and only minor, if any, thermal degradation of the natural fibres. The contact times in the sheathing process are in general from 0.5
The plastic granulate according to the invention can further contain the ingredients that are required for plastic objects, such as antioxidants, UV stabilizers, fillers, colorants, etc. Such ingredients are known to the person skilled in the art.
The invention also relates to a process for the preparation of a plastic granulate as described above. In such a preparation process it is important that the fibres are supplied in such a form that in the sheathing procedure a granulate is obtained in which the fibres are predominantly oriented in the longitudinal direction of the granulate. To that end the fibres should be combined to form one or more continuous bundles or ropes. The manufacture of such a bundle or rope as such is known to the person skilled in the art. The ropes can be of a single natural or of another fibre, they can also be a mixture of natural fibres, a mixture of one or more natural fibres with other fibres, etc.
The process according to the invention is characterized in that one or more continuous bundles of the natural fibres, optionally mixed or jointed with other fibres, is sheathed with a melt of the thermoplastic polymer, after which the product obtained (the extrudate) is cooled and cut up to the desired length. In this process use can be made of sheathing techniques known per se, such as for the sheathing of glass or metal fibres. For this purpose the thermoplastic polymer is heated, using an extruder for instance, to a temperature above the melting point and as such supplied to the sheathing apparatus.
In the process according to the invention the continuous bundles) of (natural) fibres is preferably sheathed in a first step with a low-viscous thermoplastic polymer and subsequently or simultaneously with a high-viscous polymer, with the ratio of the melt indices of the two polymers lying between and 100.
The melt index of the low-viscous thermoplastic polymer preferably lies between 50 and 250, while the melt index of the high-viscous thermoplastic polymer lies between 0.1 and 25, both measured according to ISO 1133.
The residence time, in particular that of the natural fibres, during the sheathing process is relatively short, without the occurrence of mechanical degradation of these fibres and only minor, if any, thermal degradation of the natural fibres. The contact times in the sheathing process are in general from 0.5
-5-and 1.0 second; then the product obtained is cooled down already. According as the ratio of the mass of the sheath to the mass of the fibres decreases, the effect of the invention, i.e. diminishing/eliminating the degradation of the natural fibre, increases. The proportion of fibres is therefore preferably between 20 and 85 wt.%.
The process of the present invention has the further advantage that, compared to prior art processes, the moisture content of the fibres is less critical; pre-drying of the fibres is now optional, instead of necessary.
The continuous bundle of natural fibres can also contain fibres of a thermoplastic, preferably a plastic which will melt in a subsequent shaping process and have a low viscosity, which promotes the dispersion of the natural fibres in the moulding.
With a view to promoting the later dispersion of the fibres in the moulded object it can be of advantage to spread the natural fibre-bundle slightly already before or while they are fed into the sheathing apparatus. An alternative for obtaining better dispersion is to heat the fibres before they are fed into the sheating apparatus; this improves the wetting of the fibre by the thermoplastic polymer. These steps should be done with care, however, because this enhanced spreading and/or wetting entails an enhanced risk of thermal degradation of the natural fibres in the sheathing process.
The invention also relates to a moulding made out of a plastic granulate according to the invention, for instance by injection moulding, by in-mould decorating, by extrusion (optionally followed by deep drawing) or by extrusion followed by compression. In such a moulding process the granulate is fed to a moulding machine, is heated to the moulding temperature, and the moulding is obtained.
An alternative to this moulding process can be to feed the extrudate from the sheating process directly (i.e. without the extrudate being cooled and cut up to granulate) to the moulding machine, a machine as described before. In such a process a second heating step is avoided.
The invention is illustrated below; the Examples and comparative experiments are however not intended to restrict the scope of the invention.
The process of the present invention has the further advantage that, compared to prior art processes, the moisture content of the fibres is less critical; pre-drying of the fibres is now optional, instead of necessary.
The continuous bundle of natural fibres can also contain fibres of a thermoplastic, preferably a plastic which will melt in a subsequent shaping process and have a low viscosity, which promotes the dispersion of the natural fibres in the moulding.
With a view to promoting the later dispersion of the fibres in the moulded object it can be of advantage to spread the natural fibre-bundle slightly already before or while they are fed into the sheathing apparatus. An alternative for obtaining better dispersion is to heat the fibres before they are fed into the sheating apparatus; this improves the wetting of the fibre by the thermoplastic polymer. These steps should be done with care, however, because this enhanced spreading and/or wetting entails an enhanced risk of thermal degradation of the natural fibres in the sheathing process.
The invention also relates to a moulding made out of a plastic granulate according to the invention, for instance by injection moulding, by in-mould decorating, by extrusion (optionally followed by deep drawing) or by extrusion followed by compression. In such a moulding process the granulate is fed to a moulding machine, is heated to the moulding temperature, and the moulding is obtained.
An alternative to this moulding process can be to feed the extrudate from the sheating process directly (i.e. without the extrudate being cooled and cut up to granulate) to the moulding machine, a machine as described before. In such a process a second heating step is avoided.
The invention is illustrated below; the Examples and comparative experiments are however not intended to restrict the scope of the invention.
-6-Examples I and II and comparative experiments A and B
Example I
A bundle of jute fibres was sheated in an extruder with a polypropyle polymer.
The bundle comprised 3 strands of jute, having a total tex of 2000 grams/1000 mtr.
The polypropylene polymer was a homopolymer with a melt-index (at 230 °C/2.16 kg) of 47 dg/min and a density of 905 kg/m3. The polymer also comprised Polybond~, a malefic acid anhydride modified polypropylene from Uniroyal (GB) as adhesion improver.
The extruder was a single screw extruder from Schwabenthan (DE) having a screw diameter of 30 mm. The extruder was provided with a fibre bundle guide (U4SCC) from Unitek (AT), together with pinoles having a diameter of 2.9 mm, mounted at a right angle to the extruder.
The jute bundle was passed through the extruder head at a speed of 50 m/min and sheated with the polypropylene having a melt temperature of 249 °C.
The so obtained strand was fed through a waterbath, cooled to 50 °C and cut into granulate having a length of 12.5 mm. The granulate had a fibre content of 35 wt.%.
This granulate was injection moulded to test bars with a mculding machine from Netstal (DE), and a force of 130 ton. The temperature applied was 230 °C, the injection time was 4 sec.
Comparative experiment A
The granulate of Example I was fed to a ZSK 30 twin-screw extruder from Werner and Pfleiderer (DE); the extruder had a mild screw design, appropriate for dispersing the fibres in the polymer melt. The screw speed was 250 RPM, the melt temperature 230 °C, the through-put 12 kg/hour. The obtained strand was cut into granulate and used for injection moulding as per Example I.
Example II
Example I was repeated, but now with polyethylene (Vestolen~ 1640L0 from DSM), said polymer also comprising Yparex~, a malefic acid anhydride modified polyethylene from DSM, as adhesion improver. The temperature of the melt during the sheating process was 239 °C, and during the moulding process 225 °C.
_7_ Comparative experiment B
Comparative experiment A was repeated, but now with the granulate obtained in Example II. The temperature of the melt in the ZSK was 211 °C; the throughput was 5 kg/hour.
The test bars were tested for several properties:
- Tensile strength, according to ISO 527 1 B
- Flexural strength, according to ASTM D790 - Impact strength, Izod, according to ISO 180i4A
- Linear coefficient of expansion (LCE), according to ASTM D696 (23-80 °C) - falling dart impact strength (FDI; VEM), according to ISO 66030-2V
The results of the Examples and comparative experiments are given in Table I.
Table I
Example/ comparative I A II B
experiment Properties Izod (kJ/m2) 4.3 2.9 11.4 4.2 FDI
E-total (Joules) 7.0 4.8 14.3 7.0 F-max (Newton) 1345 1364 1823 1206 Tensile test Max. strength 42.3 42.9 38.2 26.0 Elongation at break 1.2 2.6 2.4 16.5 (%) E-modulus (Mpa) 5391 4285 4464 3617 Flexural test Max. strength (Mpa) 64 65 58 41 E-modulus (Mpa) 3511 3380 2630 1785 LCE (1/K) 3.87*10~55.89*10~56.39*10~510.9*10~5 Remarks:
The test bars from comparative experiments A and B showed black discoloration.
Example I
A bundle of jute fibres was sheated in an extruder with a polypropyle polymer.
The bundle comprised 3 strands of jute, having a total tex of 2000 grams/1000 mtr.
The polypropylene polymer was a homopolymer with a melt-index (at 230 °C/2.16 kg) of 47 dg/min and a density of 905 kg/m3. The polymer also comprised Polybond~, a malefic acid anhydride modified polypropylene from Uniroyal (GB) as adhesion improver.
The extruder was a single screw extruder from Schwabenthan (DE) having a screw diameter of 30 mm. The extruder was provided with a fibre bundle guide (U4SCC) from Unitek (AT), together with pinoles having a diameter of 2.9 mm, mounted at a right angle to the extruder.
The jute bundle was passed through the extruder head at a speed of 50 m/min and sheated with the polypropylene having a melt temperature of 249 °C.
The so obtained strand was fed through a waterbath, cooled to 50 °C and cut into granulate having a length of 12.5 mm. The granulate had a fibre content of 35 wt.%.
This granulate was injection moulded to test bars with a mculding machine from Netstal (DE), and a force of 130 ton. The temperature applied was 230 °C, the injection time was 4 sec.
Comparative experiment A
The granulate of Example I was fed to a ZSK 30 twin-screw extruder from Werner and Pfleiderer (DE); the extruder had a mild screw design, appropriate for dispersing the fibres in the polymer melt. The screw speed was 250 RPM, the melt temperature 230 °C, the through-put 12 kg/hour. The obtained strand was cut into granulate and used for injection moulding as per Example I.
Example II
Example I was repeated, but now with polyethylene (Vestolen~ 1640L0 from DSM), said polymer also comprising Yparex~, a malefic acid anhydride modified polyethylene from DSM, as adhesion improver. The temperature of the melt during the sheating process was 239 °C, and during the moulding process 225 °C.
_7_ Comparative experiment B
Comparative experiment A was repeated, but now with the granulate obtained in Example II. The temperature of the melt in the ZSK was 211 °C; the throughput was 5 kg/hour.
The test bars were tested for several properties:
- Tensile strength, according to ISO 527 1 B
- Flexural strength, according to ASTM D790 - Impact strength, Izod, according to ISO 180i4A
- Linear coefficient of expansion (LCE), according to ASTM D696 (23-80 °C) - falling dart impact strength (FDI; VEM), according to ISO 66030-2V
The results of the Examples and comparative experiments are given in Table I.
Table I
Example/ comparative I A II B
experiment Properties Izod (kJ/m2) 4.3 2.9 11.4 4.2 FDI
E-total (Joules) 7.0 4.8 14.3 7.0 F-max (Newton) 1345 1364 1823 1206 Tensile test Max. strength 42.3 42.9 38.2 26.0 Elongation at break 1.2 2.6 2.4 16.5 (%) E-modulus (Mpa) 5391 4285 4464 3617 Flexural test Max. strength (Mpa) 64 65 58 41 E-modulus (Mpa) 3511 3380 2630 1785 LCE (1/K) 3.87*10~55.89*10~56.39*10~510.9*10~5 Remarks:
The test bars from comparative experiments A and B showed black discoloration.
Claims (17)
1. Plastic granulate on the basis of a thermoplastic polymer and natural fibres, characterized in that the granulate comprises a bundle of natural fibres, predominantly oriented in the longitudinal direction of the granulate, the bundle being provided with a sheath of the thermoplastic polymer and the fibre bundle being as long or virtually as long as the granulate, and wherein the decomposition temperature of the natural fibres is 20 to 80 °C higher than the melting point of the thermoplastic polymer.
2. Plastic granulate according to claim 1, characterized in that the natural fibres have been selected from the group comprising jute, flax, kenaf, sisal and hemp fibres, or mixtures thereof.
3. Plastic granulate according to any one of claims 1-2, characterized in that the decomposition temperature of the natural fibres is 35 to 70 °C
higher than the melting point of the thermoplastic polymer.
higher than the melting point of the thermoplastic polymer.
4. Plastic granulate according to any one of claims 1-3, characterized in that the thermoplastic polymer is a polyolefin.
5. Plastic granulate according to claim 4, characterized in that the polyolefin is chosen from the group of polyethylene and polypropylene.
6. Plastic granulate according to any one of the claims 1-5, characterized in that the granulate has a length of 5-40 mm.
7. Plastic granulate according to any one of claims 1-6, characterized in that the granulate has a diameter of 1-10 mm.
8. Plastic granulate according to any one of claims 1-7, characterized in that the granulate contains 20-85 wt.% of fibres.
9. Plastic granulate according to any one of claims 1-8, characterized in that the sheath, viewed from the core of the granulate, consists of a first layer of a low-viscous thermoplastic polymer and a second layer of a high-viscous thermoplastic polymer, the ratio of the melt indices of the two polymers lying between 10 and 100.
10. Plastic granulate according to claim 9, characterized in that the polymer of the first layer and the polymer of the second layer are the same polymers or polymers which are compatible with each other.
11. Plastic granulate according to any one of claims 1-10, characterized in that plastic fibres and/or glass fibres are additionally present in the granulate.
12. Plastic granulate according to claim 11, characterized in that the plastic fibres and/or the glass fibres are present in the bundle of natural fibres.
13. Process for the preparation of a plastic granulate according to any one of claims 1-12, characterized in that that a continuous bundle of natural fibres is sheathed with a melt of a thermoplastic polymer, after which the product obtained is cooled and cut up to the desired length.
14. Process according to claim 13, characterized in that the continuous bundle of natural fibres is in a first step sheathed with a low-viscous thermoplastic polymer and subsequently or simultaneously sheathed with a high-viscous polymer, with the ratio of the melt indices of the two polymers lying between 10 and 100.
15. Process according to any one of claims 12-14, characterized in that plastic fibres and/or glass fibres are additionally present in the continuous bundle of natural fibres.
18. Moulding made of a plastic granulate according to any one of claims 1-12 or obtained by means of a process according to any one of claims 13-15.
17. Process for the preparation of a mould on the basis of a thermoplastic polymer and natural fibres, characterized in that a continuous bundle of natural fibres, sheated with a melt of a thermoplastic polymer, is prepared, and without being cooled and/or cut being fed to a moulding machine.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NL1014918A NL1014918C2 (en) | 2000-04-12 | 2000-04-12 | Plastic granulate. |
NL1014918 | 2000-04-12 | ||
PCT/NL2001/000286 WO2001076841A2 (en) | 2000-04-12 | 2001-04-10 | Plastic granulate |
Publications (1)
Publication Number | Publication Date |
---|---|
CA2406263A1 true CA2406263A1 (en) | 2001-10-18 |
Family
ID=19771196
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA002406263A Abandoned CA2406263A1 (en) | 2000-04-12 | 2001-04-10 | Plastic granulate |
Country Status (9)
Country | Link |
---|---|
EP (1) | EP1272320A2 (en) |
JP (1) | JP2003530242A (en) |
KR (1) | KR20020087137A (en) |
AU (1) | AU2001289314A1 (en) |
BR (1) | BR0110016A (en) |
CA (1) | CA2406263A1 (en) |
MX (1) | MXPA02010188A (en) |
NL (1) | NL1014918C2 (en) |
WO (1) | WO2001076841A2 (en) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FI20030310A0 (en) * | 2003-02-28 | 2003-02-28 | T Mi Flaxwood Tapio Parviainen | A method of making a player and a player |
DE102007055103A1 (en) * | 2007-11-16 | 2009-05-20 | Mischok, Jürgen | Process for the production of a natural fiber reinforced plastic |
ATE530314T1 (en) * | 2007-12-21 | 2011-11-15 | Saudi Basic Ind Corp | METHOD FOR PRODUCING THERMOPLASTIC COMPOSITIONS REINFORCED WITH LONG GLASS FIBERS |
US20100320637A1 (en) * | 2007-12-21 | 2010-12-23 | Antal Boldizar | Method of making polymer/natural fiber composite pellet and/or a coupling agent/natural fiber pellet and the pellet made by the method |
Family Cites Families (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2053582A5 (en) * | 1969-07-09 | 1971-04-16 | Ciraud Pierre | Resin wetted fibre prodn |
ATE25832T1 (en) * | 1981-01-21 | 1987-03-15 | Ici Plc | FIBER REINFORCED COMPOSITES AND THEIR MANUFACTURING PROCESSES. |
ATE179358T1 (en) * | 1981-01-21 | 1999-05-15 | Kawasaki Chem Holding | GRANULES MADE OF FIBER REINFORCED COMPOSITES AND THEIR PRODUCTION PROCESS |
JPH03130132A (en) * | 1989-06-30 | 1991-06-03 | Yasushi Ninomiya | Natural fiber reinforced molded product and manufacture thereof |
JPH05177629A (en) * | 1991-03-08 | 1993-07-20 | Asahi Fiber Glass Co Ltd | Preparation of pellet |
JPH08281675A (en) * | 1995-02-14 | 1996-10-29 | Kobe Steel Ltd | Fiber reinforced resin molding and method and apparatus for molding the same |
DE19632960A1 (en) * | 1996-08-16 | 1998-02-19 | Rummel Matratzen Gmbh & Co | Elastic plastic strip, especially for slatted frames of reclining furniture |
CH691958A5 (en) * | 1997-03-10 | 2001-12-14 | Genossenschaft Biomasse Techno | Fiber A reinforced granules for injection molding of bacterially degradable moldings and a process for the production of bacterially degradable fiber-reinforced granules. |
DE19711247C2 (en) * | 1997-03-18 | 1999-09-23 | Thueringisches Inst Textil | Process for the production of long fiber granules based on fiber sliver |
ATA151398A (en) * | 1998-09-07 | 2004-02-15 | Isosport Verbundbauteile | METHOD FOR THE PRODUCTION OF THERMOPLASTIC PANELS REINFORCED WITH NATURAL FIBER MATS AND THEIR ADVANTAGEOUS USE |
NL1010646C2 (en) * | 1998-11-25 | 1999-11-19 | Dsm Nv | Moulding material, especially for extrusion compression moulding, comprises particles containing fibres with inner and outer sheath of different viscosity polymers |
DE29911623U1 (en) * | 1999-03-25 | 1999-09-23 | Thueringisches Inst Textil | Long fiber granulate made from thermoplastic staple fibers and reinforcing staple fibers |
-
2000
- 2000-04-12 NL NL1014918A patent/NL1014918C2/en not_active IP Right Cessation
-
2001
- 2001-04-10 KR KR1020027013643A patent/KR20020087137A/en not_active Application Discontinuation
- 2001-04-10 WO PCT/NL2001/000286 patent/WO2001076841A2/en not_active Application Discontinuation
- 2001-04-10 AU AU2001289314A patent/AU2001289314A1/en not_active Abandoned
- 2001-04-10 MX MXPA02010188A patent/MXPA02010188A/en unknown
- 2001-04-10 JP JP2001574339A patent/JP2003530242A/en active Pending
- 2001-04-10 EP EP01966761A patent/EP1272320A2/en not_active Withdrawn
- 2001-04-10 CA CA002406263A patent/CA2406263A1/en not_active Abandoned
- 2001-04-10 BR BR0110016-5A patent/BR0110016A/en not_active Application Discontinuation
Also Published As
Publication number | Publication date |
---|---|
AU2001289314A1 (en) | 2001-10-23 |
KR20020087137A (en) | 2002-11-21 |
NL1014918C2 (en) | 2001-10-16 |
MXPA02010188A (en) | 2003-03-10 |
JP2003530242A (en) | 2003-10-14 |
WO2001076841A2 (en) | 2001-10-18 |
EP1272320A2 (en) | 2003-01-08 |
WO2001076841A3 (en) | 2002-08-15 |
BR0110016A (en) | 2003-12-30 |
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