CA1057900A - Moulding processes and material - Google Patents
Moulding processes and materialInfo
- Publication number
- CA1057900A CA1057900A CA241,409A CA241409A CA1057900A CA 1057900 A CA1057900 A CA 1057900A CA 241409 A CA241409 A CA 241409A CA 1057900 A CA1057900 A CA 1057900A
- Authority
- CA
- Canada
- Prior art keywords
- particles
- filler material
- weight
- injection moulding
- moulding
- 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
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
- C08J9/32—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof from compositions containing microballoons, e.g. syntactic foams
-
- 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
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/022—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the choice of material
-
- 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
- B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
- B29C70/58—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising fillers only, e.g. particles, powder, beads, flakes, spheres
- B29C70/66—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising fillers only, e.g. particles, powder, beads, flakes, spheres the filler comprising hollow constituents, e.g. syntactic foam
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K7/00—Use of ingredients characterised by shape
- C08K7/22—Expanded, porous or hollow particles
- C08K7/24—Expanded, porous or hollow particles inorganic
-
- 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
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at 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
- B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
- B29K2105/06—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts
-
- 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
- B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
- B29K2105/06—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts
- B29K2105/12—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts of short lengths, e.g. chopped filaments, staple fibres or bristles
-
- 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
- B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
- B29K2105/06—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts
- B29K2105/16—Fillers
- B29K2105/165—Hollow fillers, e.g. microballoons or expanded particles
Abstract
ABSTRACT OF THE DISCLOSURE
This invention relates to a novel extrusion or injection moulding process and a novel structural foam extrusion or injection moulding material. The process comprises mixing a thermoplastic or thermosetting polymer with an inorganic filler in the form of hollow particles and the resultant mixture is extruded or moulded with the addition of a blowing agent to form a structural foam system. The inorganic filler has a specific gravity of 0.5 to 1.5 and comprises 46% to 68%
silica (SiO2), 20% to 38% alumina (Al2O3) and the ?emainder alkalies (Na2O and K2O) and iron oxide (Fe2O3). The process and the product are improved over thereof the prior art in that the moulding material is inexpensive and the process produces an article having an intermediate weight and firm surface texture without sink, a uniform foam structure, increased rigidity and a reduction of strain in the finished article.
This invention relates to a novel extrusion or injection moulding process and a novel structural foam extrusion or injection moulding material. The process comprises mixing a thermoplastic or thermosetting polymer with an inorganic filler in the form of hollow particles and the resultant mixture is extruded or moulded with the addition of a blowing agent to form a structural foam system. The inorganic filler has a specific gravity of 0.5 to 1.5 and comprises 46% to 68%
silica (SiO2), 20% to 38% alumina (Al2O3) and the ?emainder alkalies (Na2O and K2O) and iron oxide (Fe2O3). The process and the product are improved over thereof the prior art in that the moulding material is inexpensive and the process produces an article having an intermediate weight and firm surface texture without sink, a uniform foam structure, increased rigidity and a reduction of strain in the finished article.
Description
~ ~9~
1 This invention concerns a moulding material, moulding processes and articles obtained by the processes.
Numerous injection moulding processes are already known.In one such process a fluid plastics material is injected into a mould and allowed to cool, the mould being "topped up" with further quantities of the plastics material as the moulding cools and contracts in the mould. Articles produced by this process are expensive in v;ew of the high cost of the raw plastics material. In order to reduce the cost of articles produced by this process, a relatively cheap inert filler is commonly mixed with the plastics material prior to moulding. Conventional fillers are in the form of solid particles and have a high specific gravity, usually in the range of 2.0 to 4.5. Accordingly, articles made by this modified process are relatively heavy. Attempts have been made to reduce the weight of articles produced by this process by using fillers in the form of hollow particles, which thus have a lower density. However, the high moulding pressures required in the process result in breakdown of the filler particles which can become abrasive when broken, both in the moulding machine and in the mould itself, and the benefits derived from the low density of the filler are reduced.
In a further process, a plastics material is moulded with the addition of a blowing agent to create
1 This invention concerns a moulding material, moulding processes and articles obtained by the processes.
Numerous injection moulding processes are already known.In one such process a fluid plastics material is injected into a mould and allowed to cool, the mould being "topped up" with further quantities of the plastics material as the moulding cools and contracts in the mould. Articles produced by this process are expensive in v;ew of the high cost of the raw plastics material. In order to reduce the cost of articles produced by this process, a relatively cheap inert filler is commonly mixed with the plastics material prior to moulding. Conventional fillers are in the form of solid particles and have a high specific gravity, usually in the range of 2.0 to 4.5. Accordingly, articles made by this modified process are relatively heavy. Attempts have been made to reduce the weight of articles produced by this process by using fillers in the form of hollow particles, which thus have a lower density. However, the high moulding pressures required in the process result in breakdown of the filler particles which can become abrasive when broken, both in the moulding machine and in the mould itself, and the benefits derived from the low density of the filler are reduced.
In a further process, a plastics material is moulded with the addition of a blowing agent to create
- 2 -1~ 7~V
1 what is known as a "structural foam system". The blowing agent may be a chemical agent mixed with the plastics material before injection and which creates gas within the plastics material at a predetermined temperature to form a cellular structure within the plastics material. Alternatively, the same effect may be obtained by blowing an inert gas such as nitrogen into the plastics material during the moulding process. The resulting moulded article has a cellular structure and is light in weight.
An object of the present invention is to provide a relatively inexpensive moulding material, and an extrusion or injection process which can result in the extruded or moulded article having an intermediate weight and firm surface texture without sink, a uniform foam structure, increased rigidity, and a reduction of strain in the finished article.
With this object in view, the present invention pro-vides a moulding material comprising a thermoplastic or thermosetting polymer mixed with an inorganic filler material in the form of hollow particles.
With the same object in view, the present invention also provides an extrusion or injection moulding process comprising mixing a thermoplastic or thermosetting polymer with an inorganic filler material in the form of hollow particles, and extruding or moulding the resultant mixture with the addition of a blowing agent to form a structural foam system.
The particles of filler material may be in the form of hollow spheres, preferably of aluminium silicate, and preferably mixed in a ratio of 5% to 70% by weight of the total mix.
The invention further provides a structural foam $~ ~
~3~
1 extrusion or injection moulding material comprising a thermo-plastic or thermosetting polymer mixed with an inorganic filler material in the form of hollow particles and with a blowing agent, the inorganic filler material having a specific gravity in the range of 0.5 to 1.5 and having a chémical composition comprising silica as sio2 between 46~ and 68% by weiyht, and alumina as A1203 between 20% and 38% by weight, the remainder comprising alkalies in the form Na20 and K20 and iron oxide The particles of filler material are preferably of substantially the same size as particles of the polymer and may have a chemical composition of silica as SiO2 between 46% and 68% by weight, and alumina as A1203 between 20% and 38% by weight, the remainder being made up of alkalies in the form Na20 and K20 and iron oxide as Fe203. Such hollow particles are commercially available from Fillite (~uncorn) Limited under the trade mark FILLITE*.
However! the particles of filler materlal may be considerably smaller than the polymer particles, in which case a wetting agent is added during the mixing and before the moulding operation to ensure a uniform mixture and avoid se-paration of the filler and polymer particles.
Mixing may be performed immediately before the extrusion or moulding operation and at the point of feed to the extrusion or moulding machine by means of metering devices.
Preferably the filler material has a specific gravity in the range of from 0.5 to 1.5.
The blowing agent may be a chemical agent or an inert
1 what is known as a "structural foam system". The blowing agent may be a chemical agent mixed with the plastics material before injection and which creates gas within the plastics material at a predetermined temperature to form a cellular structure within the plastics material. Alternatively, the same effect may be obtained by blowing an inert gas such as nitrogen into the plastics material during the moulding process. The resulting moulded article has a cellular structure and is light in weight.
An object of the present invention is to provide a relatively inexpensive moulding material, and an extrusion or injection process which can result in the extruded or moulded article having an intermediate weight and firm surface texture without sink, a uniform foam structure, increased rigidity, and a reduction of strain in the finished article.
With this object in view, the present invention pro-vides a moulding material comprising a thermoplastic or thermosetting polymer mixed with an inorganic filler material in the form of hollow particles.
With the same object in view, the present invention also provides an extrusion or injection moulding process comprising mixing a thermoplastic or thermosetting polymer with an inorganic filler material in the form of hollow particles, and extruding or moulding the resultant mixture with the addition of a blowing agent to form a structural foam system.
The particles of filler material may be in the form of hollow spheres, preferably of aluminium silicate, and preferably mixed in a ratio of 5% to 70% by weight of the total mix.
The invention further provides a structural foam $~ ~
~3~
1 extrusion or injection moulding material comprising a thermo-plastic or thermosetting polymer mixed with an inorganic filler material in the form of hollow particles and with a blowing agent, the inorganic filler material having a specific gravity in the range of 0.5 to 1.5 and having a chémical composition comprising silica as sio2 between 46~ and 68% by weiyht, and alumina as A1203 between 20% and 38% by weight, the remainder comprising alkalies in the form Na20 and K20 and iron oxide The particles of filler material are preferably of substantially the same size as particles of the polymer and may have a chemical composition of silica as SiO2 between 46% and 68% by weight, and alumina as A1203 between 20% and 38% by weight, the remainder being made up of alkalies in the form Na20 and K20 and iron oxide as Fe203. Such hollow particles are commercially available from Fillite (~uncorn) Limited under the trade mark FILLITE*.
However! the particles of filler materlal may be considerably smaller than the polymer particles, in which case a wetting agent is added during the mixing and before the moulding operation to ensure a uniform mixture and avoid se-paration of the filler and polymer particles.
Mixing may be performed immediately before the extrusion or moulding operation and at the point of feed to the extrusion or moulding machine by means of metering devices.
Preferably the filler material has a specific gravity in the range of from 0.5 to 1.5.
The blowing agent may be a chemical agent or an inert
3~
gas such as nitrogen.
*Trade Mark 4 ~S~5~~9~)V
1 At the present -time, the cost per ton of aluminum silicate filler material in the form of hollow spheres is about 2 to 3 times as much as that of a conventional filler material. However, conventional filler material is between
gas such as nitrogen.
*Trade Mark 4 ~S~5~~9~)V
1 At the present -time, the cost per ton of aluminum silicate filler material in the form of hollow spheres is about 2 to 3 times as much as that of a conventional filler material. However, conventional filler material is between
4 and 5 times as dense as the aluminum silicate filler, and so the use of the aluminum silicate filler is cheaper on a volumetric basis. In view of this, the process of the present invention offers improved economics of material costs as compared with known extrusion or injection moulding processes.
There is a further significant cost saving, as compared with known injection moulding processes, as a result of a reduction in moulding production time cycles resulting from faster setting up in the mould of the mouldings enabling them to be ejected from the mould after a shorter period of time. This is a direct result of the inclusion of the filler.
The process of the invention also makes it easier to produ~e mouldings on both struc ~ 1 foam injection moulding machines and more conventional moulding machines.
Mouldi~gs hitherto not considered suitable as structural foam mouldings are now suitable for and benefit from this process because of increased rigidity, freedom from sinkage and faster time cycles.
The process of injection moulding in accordance with the invention facilitates the production of mouldings without the use of injection hold-on or 1 back-up pressure in 'he material after injection into the mould in order to fill the mould during cooling and contraction of the material. It is normally necessary to force more material into the mould in order to compensate for such contraction, but resulting movement of the material in a semi-molten state introduces strain into the moulding which can result in distortion of the moulding after ejection from the mould. Inclusion of the blowing agent and filler material ensures filling of the mould without further material injection and therefore the introduction of strain into the material is substantially reduced. It is thus only necessary to introduce a metered volume of material into the mould. The productior of mouldings of a high quality is thus made more consistent.
A further use of the process of the invention involves the addition of the filler material to a two-component mixture of a thermosetting foam such as poly-urethane. The foam is created by chemical reaction, and combination of the two components such as polyol and isocyanate will produce the foam with the filler dispersed therein. The resulting foam has similar advantages to those obtained for the plastics material foam.
It will be appreciated that the process may include other additives, for example reinforcements such as glass fibre which are mixed with the moulding ~ 7~
1 material at the same time as the filler. The combination of the filler and glass fibre produces a combination of improved physical properties which include increased tensile strength, increased rigidity and heat distortion whilst still retaining the advantages of a more uniform foam structure and good surface finish which result from the use of the filler.
A further improvement in the adhesion of the plastic between the filler and the thermoplastic can be obtained, with the use of a coupling agent such as silane.
This will result in further improvement in physical properties such as tensile and impact strengths and resistance to creep under load.
A further use of the process is in the extrusion of these material mixtures into profiled shapes. Advantages derived are similar to those of the injection moulded parts and include cost savings in raw material resulting from reduced weight of the extrusion and reduced material costs and increased extrudate output, increased rigidity, freedom from sinkages and dimensional stability. The extrusion of sections of 5 mm or more in thickness is made more feasible.
The cost of extrusion as a result becomes more competitive with timber.
The moulded material obtained by the process of the invention has the following advantages as compared with conventional injection moulding processes:-1 (a) Raw material costs are r~duced by the inclusion of thefiller material at a very much lower cost than that of the polymer;
(b) Reduced moulding time as a result of reduced coolin`g time in the mould before the moulding reaches a rlgidity sufficient for the moulding to be ejected from the mould, resulting in lower costs of production;
lc) A weight and surfàce texture similar to that of wood can be obtained by appropriate proportioning of the polymer and the filler material;
(d) The surface texture obtained by inclusion of the filler material facilitates painting or similar post-moulding operations such as printing and metallising. It has been found that printing can be undertaken almost immediately after moulding whereas conventional mouldings have to be stored for several days before printing. The.only surface preparation normally needed after this process is the application of a primer (in the case of polypropylenel. Surface imperfections such as "tear"
marks normally evident in polypropylene foam mouldings are eliminated;
(e) The inclusion of the filler material reduces the thermal conductivity of the moulding;
(f) The rigidity, flexural strength, dimensional stability and temperature distortion point of the plastics are increased as a result of inclusion of the filler;
(g] The mouldings are free from sinkage so that mouldings of varying thickness can be easily made by this process;
(h) The abrasion resistance of mouldings is improved;
~?57~
1 (i) The foam structure is much more uniform throughout the moulding as a result of the filler acting as a nucleating agent duriny flow of material into the mould. The occurrence of large voids in the foam is reduced; and (j) The residual strain in the moulding is reduced, so forming a more dimensionally stable moulding conforming more accurately to the shape of the mou]d.
The invention will be described further, by way of example, with reference to the following typical mixes wherein the material proportions are all by weight.
EXAMPLE 1:
Polypropylene 67.0 FILLITE* filler 32.5~
Chemical blowing agent 0.5%
EXAMPLE 2:
Polystyxene 67.0~
FILLITE* filler 32.5%
Chemical blowing agent 0.5%
EXAMPLE 3:
Polyacetol 75.0%
FILLITE* filler 24.5%
Chemical blowing agent 0.5 EXAMPLE 4:
Nylon 80.0~
FILLITE* filler 19.8%
Chemical blowing agent 0.2%
*Trade Mark 9 1 ExAMpLE 5:
Polypropylene 80.0%
FILLITE* filler 20.0~
In this example an inert gas such as nitrogen is used as a blowing agent.
EXAMPLE 6:
Polypropylene 80.0~
FILLITE* filler 19.5%
Chemical blowing agent 0.5%
This mixture is particularly suitable for extrusion into Eorm sheet.
EXAMPLE 7:
Polypropylene 94.5%
FILLITE* filler 5.0 Chemical blowing agent 0.5 EXAMPLE 8:
Polystyrene 29.5%
FILLITE* filler 70.0%
Chemical blowing agent 0.5%
It will be appreciated that the chemical blowing agents may be replaced by an inert gas blowing agent such as nitrogen, resultant with minor modification of the proportions of the plastics and filler materials. However, where a chemical blowing agent is used, that marketed by Fisons Limited under the registered trade mark GENITRON* has been found to be particularly suitable.
Although the disclosure describes and illustrates a preferred embodiment of the invention, it is to be understood the invention is not restricted to this particular embodiment.
*Trade Mark
There is a further significant cost saving, as compared with known injection moulding processes, as a result of a reduction in moulding production time cycles resulting from faster setting up in the mould of the mouldings enabling them to be ejected from the mould after a shorter period of time. This is a direct result of the inclusion of the filler.
The process of the invention also makes it easier to produ~e mouldings on both struc ~ 1 foam injection moulding machines and more conventional moulding machines.
Mouldi~gs hitherto not considered suitable as structural foam mouldings are now suitable for and benefit from this process because of increased rigidity, freedom from sinkage and faster time cycles.
The process of injection moulding in accordance with the invention facilitates the production of mouldings without the use of injection hold-on or 1 back-up pressure in 'he material after injection into the mould in order to fill the mould during cooling and contraction of the material. It is normally necessary to force more material into the mould in order to compensate for such contraction, but resulting movement of the material in a semi-molten state introduces strain into the moulding which can result in distortion of the moulding after ejection from the mould. Inclusion of the blowing agent and filler material ensures filling of the mould without further material injection and therefore the introduction of strain into the material is substantially reduced. It is thus only necessary to introduce a metered volume of material into the mould. The productior of mouldings of a high quality is thus made more consistent.
A further use of the process of the invention involves the addition of the filler material to a two-component mixture of a thermosetting foam such as poly-urethane. The foam is created by chemical reaction, and combination of the two components such as polyol and isocyanate will produce the foam with the filler dispersed therein. The resulting foam has similar advantages to those obtained for the plastics material foam.
It will be appreciated that the process may include other additives, for example reinforcements such as glass fibre which are mixed with the moulding ~ 7~
1 material at the same time as the filler. The combination of the filler and glass fibre produces a combination of improved physical properties which include increased tensile strength, increased rigidity and heat distortion whilst still retaining the advantages of a more uniform foam structure and good surface finish which result from the use of the filler.
A further improvement in the adhesion of the plastic between the filler and the thermoplastic can be obtained, with the use of a coupling agent such as silane.
This will result in further improvement in physical properties such as tensile and impact strengths and resistance to creep under load.
A further use of the process is in the extrusion of these material mixtures into profiled shapes. Advantages derived are similar to those of the injection moulded parts and include cost savings in raw material resulting from reduced weight of the extrusion and reduced material costs and increased extrudate output, increased rigidity, freedom from sinkages and dimensional stability. The extrusion of sections of 5 mm or more in thickness is made more feasible.
The cost of extrusion as a result becomes more competitive with timber.
The moulded material obtained by the process of the invention has the following advantages as compared with conventional injection moulding processes:-1 (a) Raw material costs are r~duced by the inclusion of thefiller material at a very much lower cost than that of the polymer;
(b) Reduced moulding time as a result of reduced coolin`g time in the mould before the moulding reaches a rlgidity sufficient for the moulding to be ejected from the mould, resulting in lower costs of production;
lc) A weight and surfàce texture similar to that of wood can be obtained by appropriate proportioning of the polymer and the filler material;
(d) The surface texture obtained by inclusion of the filler material facilitates painting or similar post-moulding operations such as printing and metallising. It has been found that printing can be undertaken almost immediately after moulding whereas conventional mouldings have to be stored for several days before printing. The.only surface preparation normally needed after this process is the application of a primer (in the case of polypropylenel. Surface imperfections such as "tear"
marks normally evident in polypropylene foam mouldings are eliminated;
(e) The inclusion of the filler material reduces the thermal conductivity of the moulding;
(f) The rigidity, flexural strength, dimensional stability and temperature distortion point of the plastics are increased as a result of inclusion of the filler;
(g] The mouldings are free from sinkage so that mouldings of varying thickness can be easily made by this process;
(h) The abrasion resistance of mouldings is improved;
~?57~
1 (i) The foam structure is much more uniform throughout the moulding as a result of the filler acting as a nucleating agent duriny flow of material into the mould. The occurrence of large voids in the foam is reduced; and (j) The residual strain in the moulding is reduced, so forming a more dimensionally stable moulding conforming more accurately to the shape of the mou]d.
The invention will be described further, by way of example, with reference to the following typical mixes wherein the material proportions are all by weight.
EXAMPLE 1:
Polypropylene 67.0 FILLITE* filler 32.5~
Chemical blowing agent 0.5%
EXAMPLE 2:
Polystyxene 67.0~
FILLITE* filler 32.5%
Chemical blowing agent 0.5%
EXAMPLE 3:
Polyacetol 75.0%
FILLITE* filler 24.5%
Chemical blowing agent 0.5 EXAMPLE 4:
Nylon 80.0~
FILLITE* filler 19.8%
Chemical blowing agent 0.2%
*Trade Mark 9 1 ExAMpLE 5:
Polypropylene 80.0%
FILLITE* filler 20.0~
In this example an inert gas such as nitrogen is used as a blowing agent.
EXAMPLE 6:
Polypropylene 80.0~
FILLITE* filler 19.5%
Chemical blowing agent 0.5%
This mixture is particularly suitable for extrusion into Eorm sheet.
EXAMPLE 7:
Polypropylene 94.5%
FILLITE* filler 5.0 Chemical blowing agent 0.5 EXAMPLE 8:
Polystyrene 29.5%
FILLITE* filler 70.0%
Chemical blowing agent 0.5%
It will be appreciated that the chemical blowing agents may be replaced by an inert gas blowing agent such as nitrogen, resultant with minor modification of the proportions of the plastics and filler materials. However, where a chemical blowing agent is used, that marketed by Fisons Limited under the registered trade mark GENITRON* has been found to be particularly suitable.
Although the disclosure describes and illustrates a preferred embodiment of the invention, it is to be understood the invention is not restricted to this particular embodiment.
*Trade Mark
Claims (8)
1. A structural foam extrusion or injection moulding material comprising a thermoplastic or thermosetting polymer mixed with an inorganic filler material in the form of hollow part-icles and with a blowing agent, the inorganic filler material hav-ing a specific gravity in the range 0.5 to 1.5 and having a chemical composition comprising silica as SiO2 between 46% and 68% by weight, and alumina as Al2O3 between 20% and 38% by weight, the remainder comprising alkalies in the form Na2O and K2O and iron oxide as Fe2O3, the filler material being mixed in a ratio of 5% to 70%
by weight of the total mix.
by weight of the total mix.
2. A structural foam extrusion or injection moulding mater-ial as claimed in claim 1, in which the hollow particles are spherical.
3. A structural foam extrusion or injection moulding material as claimed in claims 1 or 2, in which the particles of filler material are of substantially the same size as particles of the polymer.
4. A structural foam extrusion or injection moulding material as claimed in claims 1 or 2, in which the particles of filler material are considerably smaller than particles of the polymer and a wetting agent is added during mixing.
5. An extrusion or injection moulding process comprising mixing a thermoplastic or thermosetting polymer with an inorganic filler material in the form of hollow particles, and extruding or moulding the resultant mixture with the addition of a blowing
5. An extrusion or injection moulding process comprising mixing a thermoplastic or thermosetting polymer with an inorganic filler material in the form of hollow particles, and extruding or moulding the resultant mixture with the addition of a blowing
Claim 5 continued agent to form a structural foam system, wherein the inorganic filler material has a specific gravity in the range of 0.5 to 1.5 and comprises aluminum silicate or silica as SiO2 between 46% and 68% by weight, alumina as Al2O3 between 20% and 38% by weight and the remainder comprising alkalies in the form Na2O and K2O and iron oxide as Fe2O3, the filler material mixed in a ratio of 5%
to 70% by weight of the total mix.
to 70% by weight of the total mix.
6. A process as claimed in claim 5 in which the hollow particles are spherical.
7. A process as claimed in claims 5 or 6, in which the particles of filler material are of substantially the same size as particles of the polymer.
8. A process as claimed in claims 5 or 6, in which the particles of filler material are considerably smaller than the particles of the polymer, and a wetting agent is added during mixing.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB52574/74A GB1522620A (en) | 1974-12-05 | 1974-12-05 | Moulding processes and material |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1057900A true CA1057900A (en) | 1979-07-03 |
Family
ID=10464452
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA241,409A Expired CA1057900A (en) | 1974-12-05 | 1975-12-05 | Moulding processes and material |
Country Status (13)
| Country | Link |
|---|---|
| JP (1) | JPS5182367A (en) |
| BE (1) | BE836315A (en) |
| CA (1) | CA1057900A (en) |
| DE (1) | DE2554060C3 (en) |
| DK (1) | DK513075A (en) |
| FI (1) | FI66888C (en) |
| FR (1) | FR2293463A1 (en) |
| GB (1) | GB1522620A (en) |
| IT (1) | IT1052500B (en) |
| LU (1) | LU73913A1 (en) |
| NL (1) | NL7513776A (en) |
| NO (1) | NO149738C (en) |
| SE (1) | SE427186B (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2484427B1 (en) * | 1980-06-12 | 1985-10-11 | Inst Francais Du Petrole | NEW BUOYANCY MATERIALS CONTAINING FLY ASH |
| FR2526367A1 (en) * | 1982-05-06 | 1983-11-10 | Inst Francais Du Petrole | MULTICELLULAR COMPOSITIONS, USED IN PARTICULAR AS FLOATABILITY MATERIALS |
| JPS5947219A (en) * | 1982-09-13 | 1984-03-16 | Toshiba Chem Corp | Thermosetting resin molding material |
| GB8407311D0 (en) * | 1984-03-21 | 1984-04-26 | Walker & Co James | Shaped article of thermoplastic synthetic resin and cellular material |
| JPH028247A (en) * | 1988-04-25 | 1990-01-11 | Polyplastics Co | Polyarylene sulfide resin composition and molding for optical reflection |
| GB2225426B (en) * | 1988-09-29 | 1993-05-26 | Michael John Gill | A transducer |
| GB2246349B (en) * | 1990-07-24 | 1994-06-22 | British Gas Plc | Method for bonding together hollow glass spheres |
| DE19614022C1 (en) * | 1996-04-09 | 1997-08-28 | Ymos Ag | Thermoplastically processable polymer compound and process for its preparation and use of the polymer compound for the production of molded parts |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1235566B (en) * | 1962-04-30 | 1967-03-02 | Huels Chemische Werke Ag | Device for extrusion of foam profiles |
| DE1694653C3 (en) * | 1966-12-01 | 1973-10-25 | Minnesota Mining And Manufacturing Co., Saint Paul, Minn. (V.St.A.) | Process for the production of a filler-containing polyurethane |
| GB1186245A (en) * | 1967-11-22 | 1970-04-02 | Bp Chem Int Ltd | Filler. |
| FR1566193A (en) * | 1967-12-18 | 1969-05-09 | ||
| DE2020670A1 (en) * | 1970-04-28 | 1971-11-11 | Pittsburgh Corning Corp | Glass nodules in cellular polyurethane |
| DE2056063A1 (en) * | 1970-11-14 | 1972-07-20 | Fa. Kurt Lautenschlager, 2800 Bremen | Lightweight foam panel - esp polyurethane,with expanded perlite filler |
| DE2144687C3 (en) * | 1971-09-07 | 1976-01-02 | Gerhard Dipl.-Chem. Dr. 6114 Gross Umstadt Illing | Use of curable epoxy resins as an additive to thermoplastic synthetic resin compounds |
| FR2160637A1 (en) * | 1971-11-19 | 1973-06-29 | Idemitsu Kosan Co | Hollow mouldings - esp submarine floats mfd by rotational casting of resins with microsphere fillers |
| GB1372845A (en) * | 1971-12-15 | 1974-11-06 | Vickers Ltd | Syntactic foam elements |
| CA998205A (en) * | 1972-02-03 | 1976-10-12 | Philadelphia Quartz Company | Low bulk density filler |
-
1974
- 1974-12-05 GB GB52574/74A patent/GB1522620A/en not_active Expired
-
1975
- 1975-11-14 DK DK513075A patent/DK513075A/en not_active Application Discontinuation
- 1975-11-14 NO NO75753812A patent/NO149738C/en unknown
- 1975-11-14 SE SE7512796A patent/SE427186B/en unknown
- 1975-11-19 FI FI753261A patent/FI66888C/en not_active IP Right Cessation
- 1975-11-26 NL NL7513776A patent/NL7513776A/en active Search and Examination
- 1975-11-27 FR FR7536309A patent/FR2293463A1/en active Granted
- 1975-12-02 LU LU73913A patent/LU73913A1/xx unknown
- 1975-12-02 DE DE2554060A patent/DE2554060C3/en not_active Expired
- 1975-12-04 IT IT7552526A patent/IT1052500B/en active
- 1975-12-05 CA CA241,409A patent/CA1057900A/en not_active Expired
- 1975-12-05 JP JP50145827A patent/JPS5182367A/en active Pending
- 1975-12-05 BE BE162471A patent/BE836315A/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| NL7513776A (en) | 1976-06-09 |
| DE2554060A1 (en) | 1976-06-10 |
| FI66888B (en) | 1984-08-31 |
| FI753261A (en) | 1976-06-06 |
| SE7512796L (en) | 1976-06-08 |
| GB1522620A (en) | 1978-08-23 |
| NO149738C (en) | 1984-06-13 |
| FI66888C (en) | 1984-12-10 |
| SE427186B (en) | 1983-03-14 |
| FR2293463A1 (en) | 1976-07-02 |
| BE836315A (en) | 1976-04-01 |
| DE2554060B2 (en) | 1977-12-29 |
| IT1052500B (en) | 1981-06-20 |
| JPS5182367A (en) | 1976-07-19 |
| DE2554060C3 (en) | 1984-07-26 |
| FR2293463B1 (en) | 1979-02-02 |
| NO149738B (en) | 1984-03-05 |
| DK513075A (en) | 1976-06-06 |
| LU73913A1 (en) | 1976-07-01 |
| NO753812L (en) | 1976-06-09 |
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