Process for manufacturing a synthetic resin semifinished product and use of same semifinished product.

Translation of description of equivalent WO 8904340 A1

p0001A method for manufacturing a resin-semi-finished product and the use of this semi-finished product.

p0002Technical field

p0003The invention relates to a method for producing a semifinished product consisting of a carrier material, the strength with an optionally solvent-dependent, is impregnated and / or coated curable synthetic resin mixture. The invention further relates to an advantageous use of the semifinished product according to the invention at an occurring by curing in a mold producing a body, the mechanically supporting surface layers and in the interior has a cavity or a core lower specific gravity than the mechanically supporting surface layers.

p0004State of the art

p0005A known semi-finished product of this type is for example a SEH with a Epoxydharzhärtergemi impregnated glass fiber fabric that is generally referred to as "prepreg". Such prepregs are used for example for the production of tennis rackets. In this case, blanks from these prepregs are wound around a tube to form a layer, and - serving, together with other structure for the racquet aushärtbären fiber-reinforced plastic pieces - inserted into a mold. This bewikkelte hose case runs along the racket frame and is performed twice in the grip zone. Thereafter, the tube is inflated, pushing its prepreg winding against the mold. πnerf 1 äche. The water introduced in the form of fiber-reinforced epoxy resin is then cured at elevated temperature for tennis racket body, after which the tube is deflated and withdrawn from the tennis racket body.

p0006In a tennis racket manufacturing such now results, however, because the cross section of the racket frame is substantially rectangular and has also at its corners flat ribs, a problem that the pressure with which the prepreg Bewick Iung against Formiπnenf laugh is pressed to the ribs is not inconsiderable lower than in the other regions. But this can lead to an unfavorable distribution of resin and fiber reinforcement to the frame perimeter.

p0007Summary of the Invention

p0008The invention is based firstly on the object of a Halbfabrikät consisting of a carrier material which is impregnated with an optionally present as a solution of synthetic resin mixture and / or is coated, to specify which, in the production of articles which may be prepared in a mold at an elevated temperature used with the purpose to achieve an optimal distribution of the material in the mold.

p0009This object is to where erf induπgsgemäßen process. Production of a semifinished product dissolved, which is characterized in that the serving for the impregnation and / or coating resin mixture contains an activatable at an elevated temperature blowing agent and that the resin mixture at or in the support material at and / or heated after the impregnation or Besenichtung without thereby the resin mixture to foam by activation of the blowing agent. In this case, heating is advantageously carried out at temperatures which are lower than the temperatures at which the half-life of the blowing agent is 0.1 h.

p0010In an advantageous embodiment of the invention, said heating is carried out at temperatures which are lower than the temperature at which the half-life is 0.5 hours.

p0011According to other advantageous embodiments of the inventive process by said heating at least the major part of the solvent contained in Kunstharzgemiseh expelled and / or it is through them first - optionally in order to facilitate the impregnation and / or coating - lowers the viscosity of the resin mixture and, if appropriate, then increases its viscosity by a preliminary reaction of the resin mixture after impregnation and / or coating.

p0012According to a further advantageous embodiment of the novel process, as a carrier material in a conventional manner, a fibrous sheet material, such as a fiber fabric, a fiber laminate, a nonwoven fabric and / or along a surface, arranged parallel fiber rovings, which are impregnated with the resin mixture.

p0013In another advantageous embodiment of the erf indungsgemäßen process are used as support material an a largely compact body which is coated over at least a portion of its surface with the resin mixture, which forms a solid, foamable and optionally serving as a coat layer.

p0014The invention further has for its object to provide an advantageous use of the semi-finished products produced by the process according to the invention at an occurring by curing in a mold producing a body which mechanically supporting surface layers and inside a cavity or a lasting core lower specific weight than the mechanical comprising carrying surface layers.

p0015This object is achieved in the use according to the invention, which is characterized in that within the mold between a later cavity generating temporary core or to the permanent core and the mold inner surface - at least over a part of the mold inner surface - is attached to the semifinished product that the in the form of materials brought on them are heated so that the semi-finished material foams and characterized between the core and the mold inner surface remaining free space is filled yet and the resin mixture of the semi-finished product eventually hardens.

p0016According to an advantageous embodiment of the inventive use non expandable outer layer or ply is between Haibfabrikat layers and the mold inner surface mounted against the anschäumt the semifinished product material and thereby presses against the inner mold surface and that the foamed semi-finished material during curing connects with the top layer or sheet.

p0017According to a further advantageous embodiment of the inventive use foam to the semi-finished material to the permanent core and connects to that during curing.

p0018Brief Description of Drawings

p0019FIG. 1 shows the manufacture of a tennis racket frame using a foamable prepregs for a characteristic production phase a schematic partial section of the mold used and a cross section of the tennis racket frame.

p0020In FIG. 2, for the manufacture of a surfboard using a foamable prepregs a schematic cross-section shown by the used in the method and the arrangement form of the introduced in the form of materials.

p0021Fig. 3 shows, for the manufacture of a ski, in which a foamable prepreg is used, the ski structure within a mold schematically in cross section.

p0022In FIG. 4, 3 in a similar view as in Fig., The die and the ski construction shown in cross-section, with a get foamable resin layer coated Ski Sidewall used.

p0023Some ways of carrying out the invention

p0024The invention will be explained below with reference to the figures which illustrate some advantageous ways of carrying out the invention in the context of several examples.

p0025Example 1 :

p0026For the manufacture of a semifinished product in the form of a prepreg a Epoxydharzgemisch is used, which consists of an epoxy resin with a latent curing agent, as typically for the production of prepregs for hardening temperatures between about

p0027120 and 150 ° C is used. This Epoxydharzgemisch then 3 wt.% Azobisisobutyronitrile as a blowing agent, which has at a temperature of 102 ° C a half-life of 0.1 hours, and 1 wt.% Of a nichtioπogenen wetting agent and finely dispersed by intensive stirring in the resin mixture. These

p0028Mixture is then applied to the processing for the later than

p0029Impregnating or coating solution viscosity required diluted with acetone.

p0030In a Imprägniermasch ine now is a glass fiber fabric in web form having a basis weight of 280 g / m² impregnated with said impregnation solution and the Imprägniermittelauftrag adjusted by nip rolls. After evaporation of the acetone in a drying zone, which occurs during a residence time of about 8 minutes at temperatures of 55-70 ° C, to obtain a handle dry or slightly tacky, a resin content of about 40% exhibiting prepreg with a release paper is rolled as a liner.

p0031a propellant-free prepreg for the manufacture of a tennis racket now, in addition to the blowing agent-containing prepreg described above, is used, which - analogously to vorste- described starting - was prepared by impregnating a glass fabric with a blowing agent but now free Epoxydharzhärtergemisch. In the manufacture of a tennis racket body blanks from the propellant-free prepreg and those made from the blowing agent-containing prepreg or others for the construction of the tennis racket provided fiber-reinforced curable plastic pieces on or superimposed. This scrim is then wrapped around a hose, so that the propellant-free prepregs come lie on the outside, and the whole thing - as already mentioned the description - introduced into a heated mold and introduced into the mold materials to a temperature of about 140 ° C brought. In this case, the blowing agent is activated and the foam blowing agent-containing prepregs used in the mold to several times their original volume.

p0032Fig. 1 shows this phase of the manufacturing process in the used form with the mold halves 1 and 2 and the produced Tennisschäger frame with the outer portion 3 is what occupied by the propellant-free prepregs, the areas 4 with the foamed blowing agent-containing prepregs, as well as the inflated tube 5. the pressure in the hose 5 pressure presses the tubing wall and thus the prepreg of the areas 3 and 4 toward the Forminnenf laugh 6 is the effect of this pressure in the peripheral zones 7 and 8 by the pressure of the prepregs of the area 4 foaming propellant amplified and causes in particular in the region of the ribs 9 - the prepregs of the area 3 with sufficient pressure to be pressed against the mold inner surface. 5

p0033In an advantageous variant of this described with reference to FIG. 1 Bespiels a prepreg passes for use that is made based on a solvent-free Epoxydharzgemisches how it usually already today already used for the manufacture of prepregs in which the fibrous Support material from along a surface arranged parallel fiber rovings is formed. In this Epoxydharzgemisch consisting of an epoxy resin and a latent curing agent, at room temperature, has a viscosity of about 15,000 mPa.s and is well-curable at temperatures between about 120 and 150 ° C, will now be - analogously to the first variant of this example 1-3 wt% of azobisisobutyronitrile as a propellant, one at a temperature of 102 ° C.. has half-life of 0.1 hours, and 1 wt.% of a non-ionic wetting agent is finely dispersed.

p0034In a designed as so-called tape machine impregnating machine, the blowing agent Epoxydharzgemisch at a temperature of 60 ° C, at which its Vis¬kosität now about 700 mPa thus produced. S is plotted by means of a heatable doctor blade means in the form of a film a thickness of 0.25 mm uniformly to a continuous ribbon-shaped separating film supplied. In this thin, liquid resin film from a creel withdrawn Glasfaserrcvings now side by side placed running parallel to the resin film. The basis weight of these parallel tapered rovings amounts to 360 g / m² ,

p0035The whole is then placed or kept on passing through a heating zone with a residence time in this zone of about 6 min at temperatures between 55-70 ° C. Initially, there is a further reduction of the viscosity of the Epoxydharzgemisches wherein the rovings are well impregnated with the resin mixture, and then a pre-reaction of the resin mixture with an attendant increase in viscosity. After cooling as it passes through a cooling zone is finally obtained a tape-like release film on the resting, slightly tacky, so-called unidirectional prepreg (UD prepreg). the weight a resin content of 40.%, and is rolled up with the tape-like release film as Zwisehenlagenmaterial. a UD prepreg for the manufacture of a tennis racket frame now, in addition to the blowing agent-containing UD prepreg described above, is used which does not contain blowing agent, and that - analogously to the blowing agent-containing UD prepreg - but is produced using the blowing agent-free Epoxydharzgemisches.

p0036The preparation of the tennis racket frame is then in the same manner as described with reference to FIG. 1.

p0037Example 2: This example, which relates to the use of blowing agent-containing prepregs in the production of a surfboard, will now be explained with reference to Figure 2, which is the used in this method form with the mold halves 10 and 11 and the arrangement of the introduced into the mold materials. shows.

p0038For the preparation of the surfboard first - in lifted upper mold half 11 - propellant-free EpoxydharzGlasfasergewebe prepregs, as they were used according to Example 1, inserted in the lower mold half 10 to form a layer 12 over the edge of the mold inner surface of the lower mold half 10 at 13 rim-shaped survives. Thereafter, a lightweight core 14 of polyurethane foam - slightly smaller - has been to about the final shape of the surfboard room, with blowing agent-containing epoxy resin-glass fabric prepregs. as they were used in Example 1, wound to form a foamable layer, and the so-wound core 14 is inserted on the layer 12 in the lower mold half 10th These wound mandrel 14 now, the same blowing agent-free prepregs. as used to form layer 12, is applied in a further layer 15 which also protrudes brim-shaped at its edge at the thirteenth Subsequently, the mold is closed by placing the upper mold half eleventh In the heated mold halves, the materials used in the form now be heated to a temperature of 120 ° C, wherein the epoxy resin contained in the prepregs used elapse and foam the blowing agent-containing prepreg, these 12 and 15 press the material of the layers against dieForminnenfläche 16th The material 17 of the intumescent prepreg fills the still existing in the mold space between the core 14 and the layer 15 cavities completely and compensates for any existing slight deviations from the ideal three-dimensional shape of the lightweight core set 14. Fig. 2 shows this phase of the process sequence , The epoxy resin of the prepregs used then cured at a temperature of 120 ° C for about 30 minutes from where all the material components used in the Form¬raum stick together or bind intimately. The substantially finished Surfboard blank is then discharged from the mold and the protruding and cured at 13 layers 12 and 15 removed by machining.

p0039Example 3: Another advantageous use of a treibmittelhältigen epoxy grass fiber fabric prepreg which is realized in the manufacture of a ski is now described with reference to Fig. 3.

p0040In a conventional ski manufacturing process, the individual Ski components are connected in a mold under pressure and at elevated temperature together or glued together. Fig. 3 shows, apart from serving for forming the ends of the ski special components, the received in the mold ski construction.

p0041In this manufacturing method, an epoxy resin serving as an intermediate layer now be between the two mold halves of the mold on a rimmed steel with edges 20 skiing surface 21, in each case with the interposition of a binder layer, Glasfaserrovinglaminat 22, serving as a bottom boom mechanical epoxy Glasfaserrovinglaminat 23 and a wooden core 24 stacked. then layers are over the wood core 25 of a blowing agent-containing epoxy resin-GlasfasergewebePrepregs, a way they were used in Example 1, placed so as to cover the side surfaces of the wood core 24th A cup-shaped outer shell 26 which has been formed in a separate process, is now placed over the prepreg plies 25 and the mold is closed by applying the upper mold half 19th The cup-shaped used

p0042Outer shell is in a separate manufacturing process Made and consists, for example on its inside of a

p0043Epoxydhärz glass fabric laminate which is connected to the lie later outward next page with a decorative wear-resistant surface-layer such as an ABS layer.

p0044The ski construction is then held in the mold under pressure for 20 minutes at a temperature of about 125 ° C. The blowing agent-containing prepreg plies foams 25 and fill the space between the wood core 24 and the cup-shaped outer shell 26 completely. In the further course of the pressing cycle, the Ski.bauteile employed in the mold intimately connected with curing of the binder or the foamed prepreg plies 25 and the finished ski blank finally removed from the mold.

p0045Example 4:

p0046In this example, a semi-finished product is described according to the invention, which consists of a plate-shaped body which is coated on one side with a blowing agent-containing epoxy resin-hardener mixture. These Phenolschichtpreßstoffplatten be ground on one side and with the process described in Example 1 blowing agent containing resin mixture with a solid resin order vo.n 100 g / m² coated, which is then dried at 65 ° C and forming layer after cooling, a touch-dry binder. These coated plates are now produced in a conventional manner by cutting or milling Skiseitenwangen that - are used ith the production of a ski - as described below.

p0047A recorded in a mold ski structure, which contains the Skiseitenwangen described above is now described with reference to the schematic cross sectional representation of FIG. 4. This ski construction includes - first as described in Example 3 - with the interposition of the binder layers rimmed by Stahlkanteh 20 skiing area 21, the two. Epoxy Glasfaserrovinglaminate 22, 23 and the wood core, the side walls 24 on both sides of Hol'zkerns 24 are now 27 with the blowing agent-containing binder layer 28 is inserted to the inside and the wood core 24 and the two side lengths 27 a. Surface laminate composed of a mechanical top chord of the ski forming epoxy-glass fiber roving 29 and laminate a decorative surface 30 made of ABS, covered.

p0048The ski structure is then held in the heated press mold during 2.0 minutes to a temperature of 125 ° C. Is first effected a foaming of the binder layer 28, thereby between the wood core 24 and the two side cheeks 27 a is generated for a sufficient bonding pressure can not be achieved when using a non-foaming, customary binder to this extent. After curing the Bindemittelschiehten during the remaining press cycle of the now substantially finished ski blank of the mold is removed.

p0049Industrial applicability

p0050can abrikate Using the erf indungsgemäßen produced blowing agent plastic half easily plastic composite of various kinds, such as tennis rackets. Surfboards, skis and are produced with high quality like..