PULTRUSION METHOD FOR PRODUCING FIBRE-REINFORCED PLASTIC PROFILED SECTIONS AND PULTRUSION DEVICE

Abstract

The invention relates to a pultrusion method for producing fibre-reinforced plastic profiled sections and to a pultrusion device.

Claims

1. A pultrusion process for the production of fiber-reinforced profiles, comprising: impregnating continuous-filament fibers, continuous-filament-fiber bundles, or semifinished textile products with molten thermoplastic or liquid reactive resin to form a fiber-reinforced profile, wherein the process further comprises i) drawing the continuous-filament fibers, the continuous-filament-fiber bundles, or the semifinished textile products into and through an enclosed channel of an injection box, ii) charging the enclosed channel of the injection box with molten thermoplastic or liquid reactive resin to form saturated continuous-filament fibers, continuous-filament-fiber bundles, or semifinished textile products, iii) drawing the saturated continuous-filament fibers, continuous-filament-fiber bundles, or semifinished textile products out from the enclosed channel of the injection box into a chamber of a temperature-controllable die to cool the molten thermoplastic, or harden the reactive resin to form the fiber-reinforced profile, and iv) drawing the fiber-reinforced profile out from the chamber, wherein an internal pressure in a region of a discharge aperture of the channel is adjusted by altering a cross section of an entry aperture of the channel, by varying a set angle of at least one of wall of the channel (2) in relation to a vertical plane of the discharge aperture.

2. The process as claimed in claim 1, wherein adjustment of the angle is achieved automatically via pressure-dependent control.

3. A pultrusion device for the production of fiber-reinforced profiles by impregnation of continuous-filament fibers, continuous-filament-fiber bundles, or semifinished textile products with molten thermoplastic or liquid reactive resin comprising: an injection box comprising at least two die halves forming an enclosed channel having an entry aperture and a discharge aperture, and further comprising a chamber of a temperature-controllable die attached to the discharge aperture of the channel, wherein a cross section of the entry aperture of the channel is alterable by virtue of a variability of a set angle of at least one wall of the channel in relation to a vertical plane of the discharge aperture.

Description

[0021] FIG. 1 depicts a cross section of a portion of a pultrusion system. The continuous-filament fibers, continuous-filament-fiber bundles (rovings), or semifinished textile products 1 are drawn into the entry aperture 6 of the channel 2 of an injection box 3 made of two die halves 9 and 9, and drawn through the discharge aperture 5 of the channel 2 into a chamber of a die. Molten thermoplastic or liquid reactive resin 10 is charged into the channel 2 by way of at least one aperture 8.

[0022] FIG. 2 is likewise a cross section, differing from FIG. 1 in that the angles , have different values.

[0023] The invention will be explained in more detail with reference to the examples below.

EXAMPLE

[0024] A polyurethane system comprising the following mixture as polyol component was used as matrix material:

[0025] 62.20% by weight of a glycerol-started polyether polyol based on propylene oxide, hydroxy number (OH number)=400 mg KOH/g

[0026] 11.00% by weight of glycerol

[0027] 10.00% by weight of a propylene-glycol-started polyether polyol based on propylene oxide, hydroxy number (OH number)=515 mg KOH/g

[0028] 12.00% by weight of a propylene-glycol-started polyether polyol based on propylene oxide/ethylene oxide, hydroxy number (OH number)=57 mg KOH/g

[0029] 0.80% by weight of diisooctyl 2,2-[(dioctylstannylene)bis(thio)]diacetate (catalyst)

[0030] 4.00% by weight of MOLSIV L paste (50% dispersion of MOLSIV L powder in castor oil) from UOP (water binder)

[0031] 4 parts by weight of Luvotrent TL HB 550 (release agent from Lehmann & Voss) were admixed, and vigorously stirred, with 100 parts by weight of the abovementioned component.

[0032] A mixing and metering system was used to mix this mixture with a polymeric diphenylmethane diisocyanate (MDI) with NCO content 32.0% by weight (comprising 69% by weight of monomeric MDI with content of 2,4-MDI and 2,2-MDI totaling 8% by weight) in a mixing ratio such that the isocyanate index was 114.

[0033] Unidirectional glassfiber rovings were used as reinforcement fibers. Fiber content in the resultant profile was about 90% by weight.

[0034] A rectangular profile (60 mm5 mm) was produced. A pultrusion die of length 1 m was used. In pultrusion direction, the die had three heating zones, controlled to temperatures of 160 C./180 C./190 C. (with aperture angle 90.7) and, respectively, 150 C./170 C./180 C. (with aperture angle 91.6).

[0035] An injection box with aperture angle and 90.7 for each injection-box half (above/below) was used. A production speed of 0.5 m/min (e.g. start-up of the system) generated a pressure p=27.2 bar at the end of the injection box. Take-off force F was 0.1 t. Production speed was increased to 1.1 m/min (e.g. for production of profiles). The pressure increased to p=38.0 bar, and the force increased to F=1.8 t. This increase of pressure and of take-off force was critical, because the procedure became unstable and had to be terminated.

[0036] Change of the angle and of the injection box to 91.6 for each injection-box half (above/below) reduced both the pressure and the take-off force significantly. The established production speed of 1.1 m/min generated a pressure of p=10.2 bar and a force of F=0.1 t.

[0037] Appropriate adjustment of the aperture angle and permitted stable implementation of the procedure without problems, even at this relatively high production speed.