DE19643359A1 - Production of blowhole-free fibre-reinforced polyurethane sheet mouldings - Google Patents
Production of blowhole-free fibre-reinforced polyurethane sheet mouldingsInfo
- Publication number
- DE19643359A1 DE19643359A1 DE19643359A DE19643359A DE19643359A1 DE 19643359 A1 DE19643359 A1 DE 19643359A1 DE 19643359 A DE19643359 A DE 19643359A DE 19643359 A DE19643359 A DE 19643359A DE 19643359 A1 DE19643359 A1 DE 19643359A1
- Authority
- DE
- Germany
- Prior art keywords
- mold
- gas
- permeable membrane
- production
- polyurethane
- 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.)
- Ceased
Links
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D19/00—Degasification of liquids
- B01D19/0031—Degasification of liquids by filtration
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C37/00—Component parts, details, accessories or auxiliary operations, not covered by group B29C33/00 or B29C35/00
- B29C37/006—Degassing moulding material or draining off gas during moulding
- B29C37/0064—Degassing moulding material or draining off gas during moulding of reinforced material
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C67/00—Shaping techniques not covered by groups B29C39/00 - B29C65/00, B29C70/00 or B29C73/00
- B29C67/24—Shaping techniques not covered by groups B29C39/00 - B29C65/00, B29C70/00 or B29C73/00 characterised by the choice of material
- B29C67/246—Moulding high reactive monomers or prepolymers, e.g. by reaction injection moulding [RIM], liquid injection moulding [LIM]
-
- 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
- B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
- B29C70/28—Shaping operations therefor
- B29C70/40—Shaping or impregnating by compression not applied
- B29C70/42—Shaping or impregnating by compression not applied for producing articles of definite length, i.e. discrete articles
- B29C70/46—Shaping or impregnating by compression not applied for producing articles of definite length, i.e. discrete articles using matched moulds, e.g. for deforming sheet moulding compounds [SMC] or prepregs
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- 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
- B29K2075/00—Use of PU, i.e. polyureas or polyurethanes or derivatives thereof, as moulding material
Abstract
Description
Die vorliegende Erfindung betrifft ein Verfahren zur Herstellung von faserver stärkten, insbesondere flächigen, Polyurethan-Formteilen, bei dem die Fasern, ins besondere Langfasern, der Form im wesentlichen unvermischt zugeführt werden. Dies kann dadurch erfolgen, daß eine vorgeformte Fasermatte vor dem Gemisch eintrag in die Form eingelegt wird. Eine andere Möglichkeit besteht darin, Fasern und Gemisch gleichzeitig einzutragen, wobei die Fasern kontinuierlich in den Gemischstrahl eingebracht werden.The present invention relates to a method for producing fiber strengthened, in particular flat, molded polyurethane parts, in which the fibers, ins special long fibers, the form of which are supplied essentially unmixed. This can be done by having a preformed fiber mat in front of the mixture entry is inserted into the form. Another option is fibers and mixture at the same time, the fibers continuously in the Mixture jet are introduced.
Bei der Herstellung solcher Langfaser verstärkter Polyurethan-Formteile kommt es zum Einschluß von Luftblasen zwischen den Fasern, so daß die Formteile Hohlräume aufweisen, die lokal unzu reichende Festigkeitswerte des Formteils bedingen.In the production of such long fiber Reinforced polyurethane molded parts result in the inclusion of air bubbles between the fibers, so that the moldings have cavities that are locally unzu sufficient strength values of the molded part.
Es wurde gefunden, daß lunkerfreie Formteile hergestellt werden können, wenn nach Einfüllung der Fasern und der Polyurethan-Reaktivmischung in die untere Formhälfte vor dem Schließen der Form eine gasdurchlässige Membran auf die gefüllte Formhälfte aufgelegt wird.It has been found that void-free molded parts can be produced if after filling the fibers and the polyurethane reactive mixture into the lower one Half of the mold before closing the mold a gas permeable membrane on the filled mold half is placed.
Bevorzugt wird als gasdurchlässige Membran ein Papiervlies eingesetzt. Das Vlies ist in der Lage, an die Oberseite der Formfüllung gelangende Gasblasen aufzunehmen und flächig zu verteilen, so daß Lunker vermieden werden. Ferner bewirkt das Vlies eine thermische Isolierung gegen die obere Formhälfte. Bei den heute erforderlichen kurzen Taktzeiten bei der Herstellung solcher Formteile wird die Polyurethan-Reaktivmischung in z. B. auf 50 bis 65°C vorgeheizte Formen eingebracht, um die Polyadditionsreaktion zu beschleunigen. Durch das zwischen der oberen Formhälfte und der Reaktivmischung angeordnete Vlies wird der Tem peraturausgleich zwischen oberer Formhälfte und Polyurethan-Reaktivmischung verzögert, so daß in der Reaktivmischung enthaltende Gasblasen noch bis zur Oberseite aufsteigen und vom Vlies aufgenommen werden können.A paper fleece is preferably used as the gas-permeable membrane. The fleece is able to get gas bubbles to the top of the mold filling pick up and distribute over the surface, so that voids are avoided. Further the fleece provides thermal insulation against the upper half of the mold. Both short cycle times required today in the production of such molded parts the polyurethane reactive mixture in z. B. to 50 to 65 ° C preheated molds introduced to accelerate the polyaddition reaction. By the between the upper mold half and the reactive mixture arranged fleece is the Tem temperature compensation between the upper mold half and the reactive polyurethane mixture delayed, so that gas bubbles contained in the reactive mixture still up to Rise up and can be absorbed by the fleece.
Nach einer bevorzugten Ausführungsform wird eine perforierte gasdurchlässige Membran eingesetzt. Offenbar wird durch die Perforierung, in die die Reaktiv mischung eindringen kann, der Übergang der Gasblasen in die Membran be günstigt. Insbesondere bevorzugt weisen die Perforierungen Durchmesser auf, die in der Größenordnung des mittleren Blasendurchmessers liegen. Zum Beispiel können die Perforierungen Durchmesser von 0,2 bis 0,5 mm aufweisen. Ferner können durch die Perforierungen größere Gasmengen, die während des Auflegens der gasdurchlässigen Membran auf die Polyurethan-Reaktivmischung eingeschlos sen werden, entweichen.According to a preferred embodiment, a perforated gas permeable Membrane used. Apparently, through the perforation in which the reactive mixture can penetrate, the transition of the gas bubbles into the membrane be favorable. Particularly preferably, the perforations have diameters that are in the order of magnitude of the average bubble diameter. For example the perforations can have a diameter of 0.2 to 0.5 mm. Further Due to the perforations, larger amounts of gas can be released during the application the gas-permeable membrane included on the polyurethane reactive mixture will escape.
Als Fasern sind Glasfasern, Naturfasern, wie Jutefasern, oder Kunststoffasern, wie Polyamid- oder Aramidfasern, geeignet.The fibers are glass fibers, natural fibers such as jute fibers, or plastic fibers such as Polyamide or aramid fibers, suitable.
Sie können in Form eines Gewebes oder Wirrvlieses bevorzugt vor dem Einfüllen der Reaktivmischung in die untere Formhälfte eingelegt werden oder als Roving einer Schneidvorrichtung zugeführt, auf Längen von 3 bis 25 mm geschnitten und mittels eines Fluides (Gasstrom) gegen die in die Form einfließende Reaktiv mischung gefördert werden, wobei sie teilweise in den Strom der Reaktivmischung eindringen und von diesem benetzt werden.They can preferably be in the form of a woven fabric or tangled nonwoven before filling of the reactive mixture are placed in the lower mold half or as roving fed to a cutting device, cut to lengths of 3 to 25 mm and by means of a fluid (gas flow) against the reactive flowing into the mold Mixture are promoted, partly in the flow of the reactive mixture penetrate and be wetted by it.
Nach einer bevorzugten Arbeitsweise wird die Membran an der oberen Formhälfte- den durch sie abgebildeten Formnestteil überdeckend - fixiert, so daß die Membran durch das Schließen der Form auf die in die untere Formhälfte einge tragene Reaktivmischung aufgelegt wird.According to a preferred method of working, the membrane is covering the part of the mold depicted by them - fixed, so that the Membrane by closing the mold on the lower half of the mold wearing reactive mixture is placed.
Nach einer weiter bevorzugten Ausführungsform weist die obere Formhälfte Bohrungen auf, durch die aus der Kontaktzone zwischen oberer Formhälfte und gasdurchlässiger Membran Gas abgesaugt werden kann.According to a further preferred embodiment, the upper mold half has Holes through which from the contact zone between the upper mold half and gas permeable membrane gas can be extracted.
Die Erfindung wird anhand der beigefügten Fig. 1 näher erläutert:The invention is explained in more detail with reference to the attached FIG. 1:
Fig. 1 zeigt schematisch eine Form 1 zur Herstellung eines dreidimensional geformten, flächigen Polyurethan-Formteils. Die Form 1 besteht aus einer unteren Formhälfte 2 und einer oberen Formhälfte 3. In der unteren Formhälfte 2 befindet sich ein Gemisch 4 aus Polyurethan-Reaktivmischung und Langglasfasern, das in die geöffnete Form eingebracht wurde. Vor dem Schließen der beiden Formhälften 2 und 3 wird die gasdurchlässige Membran 5 aufgelegt. Sie besteht beispielsweise aus einem Papiervlies mit einer Dicke von 0,05 bis 0,3 mm. Die obere Formhälfte 3 weist ferner Bohrungen 6 auf, die zu einer durch den Pfeil 7 angedeuteten Absaugvorrichtung führen. Fig. 1 shows schematically a mold 1 for producing a three-dimensionally shaped, sheet-like molded polyurethane part. The mold 1 consists of a lower mold half 2 and an upper mold half 3 . In the lower mold half 2 there is a mixture 4 of a reactive polyurethane mixture and long glass fibers, which has been introduced into the opened mold. Before the two mold halves 2 and 3 are closed , the gas-permeable membrane 5 is placed on top. For example, it consists of a paper fleece with a thickness of 0.05 to 0.3 mm. The upper mold half 3 also has bores 6 which lead to a suction device indicated by the arrow 7 .
Ein nach dem erfindungsgemäßen Verfahren ohne Absaugung hergestelltes Formteil zeigte auf seiner mit dem Papiervlies beschichteten Rückseite fleckige Strukturen, die auf einer ungleichmäßigen Benetzung des Papiervlieses durch die Polyurethan-Reaktivmischung beruhen. An den Stellen, an denen das Papiervlies Gasblasen aufgenommen hatte, konnte die Polyurethan-Reaktivmischung nicht in das Vlies eindringen. Das Formteil selbst war poren- und lunkerfrei. Bei einer Wiederholung des Versuchs mit Absaugung durch die Oberform wurde eine fleckenfreie Rückseite erhalten. Durch Absaugung des vom Vlies aufgenommenen Gases konnte das Vlies vollständig von der Polyurethan-Reaktivmischung benetzt werden.A manufactured according to the inventive method without suction Molded part showed spotty on its back coated with the paper fleece Structures based on an uneven wetting of the paper fleece by the Reactive polyurethane mix based. Where the paper fleece Had absorbed gas bubbles, the polyurethane reactive mixture could not penetrate the fleece. The molded part itself was free of pores and voids. At a Repetition of the experiment with suction through the upper mold was a preserved stain-free back. By suction of the absorbed by the fleece Gases was able to completely wet the fleece with the polyurethane reactive mixture will.
Claims (5)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19643359A DE19643359A1 (en) | 1996-10-21 | 1996-10-21 | Production of blowhole-free fibre-reinforced polyurethane sheet mouldings |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19643359A DE19643359A1 (en) | 1996-10-21 | 1996-10-21 | Production of blowhole-free fibre-reinforced polyurethane sheet mouldings |
Publications (1)
Publication Number | Publication Date |
---|---|
DE19643359A1 true DE19643359A1 (en) | 1998-04-23 |
Family
ID=7809315
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
DE19643359A Ceased DE19643359A1 (en) | 1996-10-21 | 1996-10-21 | Production of blowhole-free fibre-reinforced polyurethane sheet mouldings |
Country Status (1)
Country | Link |
---|---|
DE (1) | DE19643359A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19813105C2 (en) * | 1998-03-25 | 2001-03-01 | Daimler Chrysler Ag | Process for the production of fiber composite components |
EP2018953A1 (en) * | 2007-07-23 | 2009-01-28 | Yuan Min An Enterprise Co., Ltd. | Forming method for fiber reinforced resin |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3325327C2 (en) * | 1982-07-24 | 1986-06-12 | Rolls-Royce Ltd., London | Vacuum forming process for articles made of fiber-reinforced composite material |
DE3915693C1 (en) * | 1989-05-13 | 1990-06-13 | Messerschmitt-Boelkow-Blohm Gmbh, 8012 Ottobrunn, De | Moulding finishing arrangement - includes FRP forming air tight contact with moulding |
-
1996
- 1996-10-21 DE DE19643359A patent/DE19643359A1/en not_active Ceased
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3325327C2 (en) * | 1982-07-24 | 1986-06-12 | Rolls-Royce Ltd., London | Vacuum forming process for articles made of fiber-reinforced composite material |
DE3915693C1 (en) * | 1989-05-13 | 1990-06-13 | Messerschmitt-Boelkow-Blohm Gmbh, 8012 Ottobrunn, De | Moulding finishing arrangement - includes FRP forming air tight contact with moulding |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19813105C2 (en) * | 1998-03-25 | 2001-03-01 | Daimler Chrysler Ag | Process for the production of fiber composite components |
EP2018953A1 (en) * | 2007-07-23 | 2009-01-28 | Yuan Min An Enterprise Co., Ltd. | Forming method for fiber reinforced resin |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
OP8 | Request for examination as to paragraph 44 patent law | ||
8131 | Rejection |