AU765119B2

AU765119B2 - Moulded article

Info

Publication number: AU765119B2
Application number: AU22939/00A
Authority: AU
Inventors: Martin Hintermann
Original assignee: Alcan Technology and Management Ltd
Current assignee: 3A Composites International AG
Priority date: 1999-02-17
Filing date: 2000-01-28
Publication date: 2003-09-11
Anticipated expiration: 2020-01-28
Also published as: DE50003528D1; JP2002537146A; EP1154893B1; WO2000048824A1; CH693627A5; AU2293900A; CA2368046A1; EP1154893A1

Description

-1- This invention relates to fibre-reinforced moulded parts made from a textile fabric in the form of a woven fabric made of at least two fibre materials, a method for the production thereof and the use thereof according to the pre-characterising part of claim 1.

It is known to produce moulded parts, e.g. by means of glass mat-reinforced thermoplastics. To this end, a thermoplastic moulding compound and glass-fibre mats are processed to form a fibre composite material by a pressing process. This method is used predominantly for the production of sheets. The disadvantage is that it is essentially only possible to produce planar or sheet-like structures. Structured moulded parts or components cannot be produced or only indirectly via the planar sheet-like structures in an additional forming step.

The closest prior art, namely EP 0 630 735; discloses a hybrid yarn made of two thennoplastic fibre materials processed to form textile fabrics. The textile fabric is converted into a fibre-reinforced plastic part in a pressing process, a first fibre material, preferably in the form of staple fibres, being melted under the influence of pressure and heat and converted into the matrix-forming material, while a second, stretchable fibre material, preferably in the form of continuous filaments, remains in the plastic part as a reinforcing material.

EP 0 835 741 describes the production of a preform containing a reinforcing material in the form of rovings of staple fibres, the fibres of the rovings at most displaying slight twisting relative to one another. The preform made of oriented or unoriented rovings is impregnated with a matrix material and processed to form fibre-reinforced plastic parts.

EP 0 302 989 describes a woven fabric made of yams for the production of fibrereinforced plastic parts. The woven fabric contains different yans made of first and second materials. The yams made of a first material consist of matrix-forming material and are converted into a matrix structure under the influence ofpressure and heat during the production of the plastic part. The yams made of the second material form the fibre reinforcement in the plastic part.

0 I a a a a oo• go• 1A The above discussion of documents, acts, materials, devices, articles and the like is included in this specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters formed part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed in Australia before the priority date of each claim of this application.

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Documenti S. 55* *5* S S S. S 55 5 5 S 55S S S 55.5 S S S 5 5 5 *55 S 5 5 5 S S S S 55 5 S S S S S SS 5055 555 5 555 5 '2 The aim of this invention is to avoid these disadvantages a4nd in particular, to provide moulded p arts and a method for the production thiereof, which, departing from a fibre material, leads to moulded parts or components in one step and short processing times.

This is achieved according 'to the invention by a fibre-reinforced mould part according to claim 1.

The textile fabrics can bd oriented fibres in ulnidirectional layers, i iietoa layers, in the form of cut To vngs, non-woven fabrics, woven fabrics or knitted fabrcs.

The staple fibres of the firkt material advantageously have an average length of 10 to 150 nun, advantageously 30b to 120 mmn, preferably 60 to 100 mmn and, in particular, to 85 MM.

The staple fibres of the second material advantageously'have an average length of to 150 mm, advantageously 3 0 to 120 mm, preferably 60 to 100mm and, in particular, to In particular,.the textile rabrics contain staple fibres made of the first and second materials each with an average length of 75 to 85 mm.

The staple fibres made of thie, first thermoplastic material may contain or consist of, e.g. polyamides, polyesteis' polycarbonates, polyuretdhaes, polyurea, polyolefins, ~polystyrenes, polyacrylonitriles, polyvinyl chloride, poyiyiee chloride, polyvinyl alcohol or polytetmafluoroethylene. Staple fibres made of polyamides, such a s PuiYwamie 6, polyamide 6,6, polyamide 11I or, in particular, pui.aymide 12 are preferred.

The staple fibres Made* of the second material are, e.g. high-temperature-resistant inorganic Or Organic fibres. E.g. organic staple fibres may contain or consist of completely a romati c polyamides% aramides, aromatic -polyamides containing eteovylespolimiespolyhmide amides, polybenzimidaz'oles, polyoxadiazoles, polytria oles, polYthiadiazolcs, POlybenzoxazolesv polyquazolidies, poly-bisbenizimidazole benzophenanthroline or chelated polyterephthylDalyidrazo 0 e Other. examples are inorganic staple fibres advantageously containing or consisting of 3 glass, slag, stone, ceramics, quartz, silica glass, boron, silicon carbide, boron nitride, boron carbide, aluminium oxide, zirconium oxide, steel, aluminium, tungsten, carbon or graphite or possibly monocrystalline corundum or monocrystalline silicon carbide.

Staple fibres made of glass, carbon or graphite are preferred. Other examples are staple fibres made of natural substances, advantageously containing or consisting of cotton, wool, silk or fibres made ofjute, sisal, coconut, linen or hemp, etc..

In order to control their properties, the staple fibres made of thermoplastic material, and also, in particular, the staple fibres made of organic materials made of the second material may contain fire-retardant additives, pigments, dyes, fillers, etc..

The temperature range of the softening, melting or decomposition point of the staple fibres made of the second material is selected, e.g. in such a manner that it is at least advantageously 10 and, in particular, 30 higher than the softening or melting point of the first material.

In the moulded part according to this invention, the staple fibres made of the second Smaterial are embedded in the form of oriented fibres in unidirectional layers, in bidirectional layers, in the form of cut rovings, non-woven fabrics, woven fabrics or knitted fabrics in the matrix, which is the resolidified product of plasticised staple fibres made of the thermoplastic first material. The fibre orientation of the original textile fabric thus remains stretched. The textile fabric made of oriented fibres in unidirectional layers, in bidirectional layers, the cut rovings, non-woven fabrics, woven fabrics or knitted fabrics can be used in one or more layers, e.g. 1, 2, 3, 4, etc. layers, according to the desired final thickness and strength of the moulded parts.

Stretching of, e.g. up to 20 can advantageously be effected in single-layer textile fabrics, while stretching of up to 35 or more can advantageously be effected with multi-layer, e.g 4-layer textile fabrics. The textile fabrics can have, e.g. a density of 100 to 1000 g/m 2 In this moulded part, the staple fibres made of the second material make up 40 to 70 advantageously 50 to 60 and preferably 53 to 59 in relation to volume and, in a corresponding manner, the matrix made of the thermoplastic first material makes 0 g 0 S. o S 5.o 0 *S 4 up 60 to 30 advantageously 50 to 40 and preferably 47. to 41 in relation to volume.

This invention also includes textile fabrics made of oriented fibres in unidirectional layers, bidirectional layers, in the form of cut rovings, non-woven fabrics, woven fabrics or knitted fabrics made of a mixture of staple fibres made of at least two materials, the staple fibres made of at least one thermoplastic first material being present in quantities of 60 to 30 in relation to volume and the staple fibres made of at least one second material being present in quantities of 40 to 70 in relation to volume, for the production of the moulded parts according to the invention. The staple fibres are in a hybrid yam or a mixed yar made of the first material or materials and the second material or materials. The hybrid yam made of the staple fibres is processed to form a woven fabric. The woven fabric can be a 1-1, 1-2, 1-3, 1-4, 1-5, etc. woven fabric, i.e. the weft threads can each lap alternately under or over 1, 2, 3, 4, 5, etc, warp threads. The fibre orientation can be, e:g. 00/900. A satin 4-1 woven.fabric is particularly preferred. The textile fabrics can be used in 1, 2, 3, 4, etc. layers, with single-layer, 2-layer, 3-layer, 4-layer or 5-layer woven fabrics being preferred. It is also possible to use a higher number of layers depending on the final thickness of the moulded part, or the number of layers can vary within one moulded part. E.g. regions of the finished moulded part subjected to high stress can be reinforced by means of a plurality of layers, while regions subjected to less stress are .o l a.s designed with one layer or a few layers. In the case of two or more layers, the fibre orientation of the individual layers can be the same or twisted and/or offset relative to one another.

The textile fabrics can be used in 1, 2, 3,4, 5, etc. layers, with single-layer, 2-layer, 3-layer, 4-layer or 5-layer woven fabrics being preferred. It is also possible to use a higher number of layers depending on the final thickness of the moulded part, or the number of layers can vary within one moulded part. E.g. regions of the finished moulded part subjected to high stress can be reinforced by means of a plurality of layers, while regions subjected to less stress are designed with one layer or a few layers, In the case of two or more layers, the fibre orientation of the individual layers can be the same or twisted and/or offset relative to one, another.

C m m a a a. The oriented fibres in unidirectional layers, bidirectional layers, in the form of cut rovings, non-woven fabrics, woven fabrics or knitted fabrics and thus, in particular, the staple fibres made of the second material can be provided on their surfaces with adhesion promoters, such as adhesion promoter-containing sizes, plastic sizes, such as PA 6,6 sizes, etc.. The oriented fibres in unidirectional layers, bidirectional layers, in the form of out rovings, non-woven fabrics, woven fabrics or knitted fabrics made of a mixture of staple fibres made of at least two materials can be subjected to a drying process before shaping, wherein drying can be effected at an elevated temperature, e.g. at temperatures in the range of 60 to 110 0 C, and/or in vacuo, e.g. at 100 to 500 mbar.

The moulded parts according to the invention made from textile fabrics with oriented fibres in the form of woven fabrics made of at least two fibre materials can be produced in that the woven fabric is made of a mixture of staple fibres made of at least two materials, wherein the woven fabric is made of a hybrid yam of staple fibres, the staple fibres of the hybrid yarn are made of a first material or first materials and a second material or second materials, the staple fibres made of at least one thermoplastic first material make up 60 to 30 in relation to volume, the staple fibres made of at least one second material made of inorganic fibres make up 40 to 70 in relation to volume, and the woven fabric is-preheated until the first material softens or is melted and is then placed in a tool and is formed into the moulded part with the application of pressure fbr shaping and with the tool and the punch at a constant elevated temperature in a range below the softening or melting point of the first material.

The pressing process is carried out in a tool or female mould with the application of pressure by means of a punch or male mould for shaping and with the punch and the tool at temperatures below the softening or melting temperatures of the first material.

This process is also referred to as a cold-stamping process.

Preheating can be effected by means of radiation, such as IR radiation, or by convection, etc.. The preheating temperature depends on the melting temperature of the first material and is higher [higher] than the melting point of the first material and S. S S S S *5 S C 6 lowerthan a softening, melting ordecomposition point of the second material. E.g. if the first material is a polyamide 12, a preheating temperature of up to 250 0 C can be used. The textile fabric can be, e.g. placed on a frame or tensioned in a frame and heated by radiation or can be situated on a heat source and heated by contact heating.

In the latter case, the first material must be prevented from adhering to the heated support. During preheating, the temperature of the textile fabric must be increased until plastic deformation or melting of the first material. The preheated textile fabric with the softened or melted first material is plastically deformed, at least to such an extent that its fibre structure disappears and a matix is formed, while the staple fibres of the second material retain their fibre structure and fibre orientation, embedded in the matrix, i.e. consolidation takes place. The preheated.textile fabric is then advanced to the next treatment step.

The mould can be, e.g. a tool, cavity or female mould. The staple fibres can be inserted or placed in the tool, also referred to as a cavity or female mould, in the form of a consolidated, preheated textile fabric in the form of oriented fibres in unidirectional layers, bidirectional layers, in the form of cut rovings, non-woven fabrics, woven fabrics or knitted fabrics made of the mixture of staple fibres, and pressure can be applied thereto by means of a rigid or flexible punch, also referred to as a male mould. Forming can be carried out withthe tool or the tool and the punch at a substantially constant elevated temperature. The temperature of the tool or of the tool and the punch is advantageously slightly lower than the softening or melting temperature of the first material. The residual heat from the preheated textile fabric or from the matrix containing the staple fibres made of the second material should be sufficient for the forming step. During the forming step, essentially the matrix and the staple fibres made from the second material embedded therein are forced into the shape of the tool and the punch, so as to form the moulded part. Partial cooling takes place between the tool and the punch, the matrix made of the first material formed thereby solidifying. The mouldedpart can then be removed from the tool. Cooling to ambient temperature can take place outside the pressing mould. The residence time in the press for forming can be, e.g. less than 20 sec, advantageously less than 10 sec b •a a. a a a a 1 a- 7 and, in particular, 3 to 6 sec. A typical residence time is 5 sec. These residence times allow for a high cycle frequency during the series production of moulded parts.

The textile fabrics made of oriented fibres in unidirectional layers, bidirectional layers, in the form of cut rovings, non-woven fabrics, woven fabrics or knitted fabrics are deformed by the pressing pressure in accordance with the negative form of the tool and punch. Isostatic pressing is preferred. Isostatic pressing is advantageously effected by means of a rubbery-elastic punch. It is thus possible to form, e.g. moulded parts with a bottom part and inclined or vertical side walls, or undercuts can also be produced in the case of multi-part tools. Forming can take place in accordance with the principle of thermoforming, i.e. forming by redrawing the material with the material thickness remaining constant, stretch forming, i.e. by fixing the material along its side edges by means of a holding device and stretching the material thereby reducing its thickness, a combination of stretch forming and thermoforming, i.e. only partial redrawing of the material to be formed, or by vacuum forming. Stretch forming is preferred. In the stretching operation during stretch forming or combined stretch forming and thermofonning, the staple fibres of the second material, incorporated in the matrix formed from the first material, are subjected to lengthening with a simultaneous reduction in thickness. The individual fibres or fibrils forming the staple fibres are substantially enveloped by the plastic or melted thermoplastic first material and, supported by a resulting fibre sliding effect, the staple fibres are lengthened with a reduction n their thickness in a fibre sliding process.

E.g. a draw ratio Q of 1 to 3, preferably 1.2 to 2.1 and, in particular, 1.8 to 2:0 can be used for thermoforming and/or stretch forming. The draw ratio 0 is the quotient of the given length a to the stretched length b. The draw ratio therefore follows from the formula 2 2 a/b. The given length a corresponds to the actual wall length of the moulded part, while the stretched length b corresponds to the length of the projection ofthe moulded part.

The tool or female mould beatable. At least the forming surface can be made of chromium, chromium steel,aickel, Teflon, nickel Teflon, etc. for easy removal from the mould. The metal surfaes are advantageously smooth and, in particular, polished S 8 or lapped. Release agents and/or non-stick agents may also be applied for easy removal from the mould after the pressing process.

At least the forming parts of a rubbery-elastic male mould or rubbery-elastic punch are made, e.g. from silicone rubber. The male mould or the punch can also be heatable.

The temperature for the forming of the consolidated material inserted between the tool and the punch.depends on the softening or melting temperatures of the first material The temperature for forming and consolidation is advantageously lower than the melting point and, in particular, lower than the crystallisation temperature of the first material, E.g. for polyamides and thus preferably polyamide 12, temperatures of 700°C to 160°C are expedient, with temperatures of 110°C to 150 0 C being advantageous.

The pressing pressures are, e.g. 25 to 100 bar, advantageously 40 to 60 bar and, in particular, 50 bar. The thickness of the moulded parts according to the invention can Sbe selected in accordance with the thickness of the textile fabric and the number of jointly compressed layers. Typical thicknesses of moulded parts are, e.g. 0.5 to 5 mm.

The thickness can be varied within a moulded part The moulded parts can be, e.g.

shaped structural parts or sheet-like parts (referred to as organic panels), etc..

S: The moulded parts according to this invention can be used on vehicles for water, road or rail or on stationary structures. Examples of parts of this kind are doors, bonnets, side parts, front and rear panels, impact surfaces, trim panels, partition walls, reinforcements or brackets on vehicle bodies, panels, walls, partition walls, floors, ceilings or parts thereof on buses or railway carriages, trim panels, partition walls, etc.

in ships, or panelling, partition walls, adjustable walls, floor or ceiling elements on external facades or in the internal fixtures of stationary structures, such as buildings, etc.. Preferred applications are doors, bonnets, side parts, front and rear panels, impact surfaces, utderbodies and roofs or parts thereof for passenger cars and light goods vehicles.

a a a a oo o -9- Throughout the description and claims of this specification, the word "comprise" and variations of the word, such as "comprising" and "comprises", is not intended to exclude other additives, integers or process steps.

Example: 1. A fibre mat with a surface area of 500 g/cm 2 consisting of 4 layers of a satin 4-1 woven fabric with a fibre orientation of 00/900 made of a hybrid yam of staple fibres ,consisting essentially of 44 by volumepolyamide staple fibres and 56 by volume carbon staple fibres having an average length of 80 mm was placed on a frame, heated to approximately 220 0 C in 75 sec by IR radiation and kept at this temperature for approximately 10 sec for consolidation. The polyamide staple fibres thus lost their structure and were formed into a matrix enveloping the carbon fibres. This preheated intermediate product was placed on the tool heated to approximately 150 0 C and fixed at its edges by a holding device and the punch with the rubbery-elastic shaping surface was lowered into the tool. The closing time of the press was approximately 3 sec, the pressure applied was 50 bar and the residence time under pressure in the press was 5 sec. During the pressing process, the intermediate product made of the fibre mat was plastically deformed. The desired contours of the moulded part were formed from the matrix by the negative form of the tool and by the punch. The carbon fibres were stretched or lengthened during the pressing process by the fibre sliding effect with their thickness being reduced in accordance with the depth of draw of the tool. The negative form of the tool provided a spherical recess. The intermediate product made of the fibre mat was pressed into the recess by the punch, the staple ibres of the second material being lengthened by up to 35 of their original length in accordance with their position in the spherical recess. The original fibre orientation of the woven fabric was retained. After the pressure of the punch was removed, the finished moulded part could be removed from the tool and possibly further processed by deflashing and/or by other treatments, such as lacquering, coating with films and the like. The thickness of the moulded part was approximately mm.

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Claims

1. Fibre-reinforc lded dd part made from a textile fabric in the form of a woven faic made of at least two. fibre materials, wherein the woven fabric is made of a hybrid yarn of staple fibres, the staple fibres of the hybrid yam are made of a first material or first materials and a second material or second materials and the moulded part contains a matrix, which is the resolidified product of plasticised staple fibres made of at least one thermoplastic first material and, embedded in the matrix; oriented fibres in the form of staple fibres made of at least one second material, the staple fibres of the second material being made of inorganic fibres, a sofobning, melting or decomposition point of the staple fibres made of the second material being higher than the softening or melting poit of the fst material and the fibre orientation of the second material in the matrix corresponding to the fibre orientation of the textile fabric, characterised in that the woven fabric is made of a mixture of staple fibres made of at least two materials, wherein the woven fabric is made of a hybrid yam of staple fibres, thie staple fibres of the hybrid yam are inade ofa fArst material or first materials and a second material or second materials, the staple fibres made of at least one thermoplastic frst material make up 60 to 30 in relation to volume and the staple fibres made of at least one seconid material made of inorganic fibres make up 40 to 70 in relation to volume

2. Moulded part cbrd claim: characterised in that the staple fbres of the Bt material have an average length of 10.to 150 mm, advantageously 30 to 120 mm, preferably'60 to 100 mm. and, in particular, 75 to 85 mm.

3. Moulded part according to claim I, characterised in that the staple fibres of the serond material have an average length of .10 to 150 mm, advantageously 30 to 120 mm, preferably 60 to 100 mm and, in particular, 75 to 85 mnm. 4 Moulded part according to claim 1, characterised in that the staple fibres made of the first thermoplhasic mnaterial contain or consist of polyamides, preferably polyaid 12, polyesters, polycarbonates, polyuethanespolyurea, polyolefins, plrhe 0*0 0 *e S SS S***S polYstyrenes, polyactylonitriles,, polyvinyl chloride, polyvinylidene chloride, Polyvinyl alcohol orpolytetrafluoroeflylene., Moulded part According to claim1, characterised in that the second material contains or consists of inorganic staple. fibres made of glass, slag, stone, ceramics, quartz, :silica glass, boron, silicon carbide, boron nitride,. boron carbide, aluminium oxide, zirconium oxide,.steel,. aluminjiuni, tungsten., preferbly carbon, graphite or monocrystallie corundum and silicon carbide.

6. Moulded part according to Claim 1, characterised in that the temperature range of -the softening, meltingo decompositi. point of the staple fibres made of the second material is at least 5 O/d,-advantageously 10 and, in particular, higher than the softening or melting point of the first material.

7. M~oulded part accordin gto claim chaaterised in that, in. the moulded part, the staple flibres; made of the second material in the form of a woven fabric are embedde in thematix bch lis th resolidified product. of plasticised staple fibres made of the thermoplastic first material.

8. oiddpart according to claim 1, characteised in that, in the moulded part, the stale~brs ad ofth scond material mAkep 40 to70 %,advantagously to and preferably 53 to 59 in relattion. to'volume and, in a corresponding *manner, the matrix made. of.-the' thermoplastic first material makes up 60 to 30 .advantageouslyso0 to.40 %and preferably 47 to 41 in relation to volume. Mouled. part according to claim 1, characterised in that the mnoulded part is the :matrix made of-tthe thermoplastic. first material or materials and containng, embedded: in the matriX,. the. oriented. fibres. in. the form of staple fibres made of the. second material or materials, the fibre orientation of the second material in the marx orsponding toth fibre orientation ofth textile fabric. and the staple firesQfthesecndmaterial or mateiain jthe m*atrix bein glinner than in the-. textile falbric as a result of W.trecig Mehdopro lqqiq&g moxlded paits made fxom text1ifabrics with oriented fibres i01th for of A woven fabric'mad of at leat two fibre materials according to claim. 1T wherin the woven faic: is, maeo yrd yarnof staple fibres, te Z 12 staple fibres of the hybrid yam are made of a first material or first materials and a second material or second materials, the staple fibres made of at least one Sthermoplastic first material make up 60 to 30 in relation to volume, the staple fibres made of at least one second material made of inorganic fibres make up to 70 in relation to volume, and the woven fabric is preheated until the fst material softens or is melted and is then placed in a tool and formed into the moulded part with the application of pressure for shaping and with the tool and the punch at a constant elevated temperature in a range lower than the softening or melting point of the first material.

11. Method of producing moulded parts according to claim 10, characterised in that thetextile fabric is formed into the moulded part by stretching the staple fibres of the second material and thereby reducing their thickness, the fibre orientation remaining constant with respect to the textile material.

12. Method of producing moulded parts according to claim 10, characterised in that S. the pressure for shaping is applied isostatically.

13. Use of the moulded parts according to claim 1 for vehicles for water, road or rail or parts thereof, or for stationary structures or parts thereof.

14. A moulded part according to claim 1 substantially as hereinbefore described with reference to the example.

15. A method according to claim 10 substantially as hereinbefore described with reference to the example. DATED: 24 June 2003 PHILLIPS ORMONDE FITZPATRICK Attorneys for: ALUSUISSE TECHNOLOGY MANAGEMENT LTD. a a a a a •q a a.