Process for continuously producing fibre-reinforced thermoplastic webs, the fibre-reinforced thermoplastic webs and their use.

The invention relates to a continuous process for producing fiber-reinforced, unidirectional (UD -) - continuous filaments-containing thermoplastic webs, fiber-reinforced thermoplastic webs which are prepared by this method as well as the use of these fiber-reinforced thermoplastic webs.

Fiber-reinforced thermoplastic webs or thermoplastic sheets are high-quality construction materials, which are usually finish-subsequently in a hot pressing in heated molding under pressure to the desired moldings. They are mainly in machine and apparatus, used in the automotive and aircraft industries, sports and household appliances. Particularly high mechanical property values ​​can be achieved as the fiber reinforcement with the use of UD UD filaments or rovings.

A particular problem in the manufacture of such composite materials is the good impregnation and wetting of fiber reinforcement with the thermoplastic, which is essential for obtaining good mechanical properties. Particularly difficult good wetting when using UD-filaments is achieved, in particular when these bundled as present rovings. In EP-B1-0056703, this difficulty is overcome by the fact that to achieve good wetting and hence good mechanical properties, be used as thermoplastics, high performance polymers with very low melt viscosity. Here, the parallel-aligned reinforcing filaments are drawn in a Schmelzpultrusionsverfahren via a spreading device through the melt of the thermoplastic, whereby the melt is first melted in a separate process step from the thermoplastic powder by external heating elements or extruder. In DE-OS 3724155 a good wetting by the use of a polypropylene is obtained having a bimodal molecular weight distribution, with both high molecular weight and low molecular weight polypropylenes can be used. It is also possible, a low viscosity and thus good wetting of the reinforcing fibers by dissolving or dispersing the thermoplastic in a solvent or dispersing agent (US Patent No. 4,058,581, WO 86/03449) or by the addition of viscosity degrading foreign polymers (US- PS 4438236) to achieve.

The disadvantage of this process that require especially low viscosity of the thermoplastic, is mainly due to the limitation in the selection of the thermoplastic, since to achieve a sufficient wetting precisely only those having low viscosity, or only specific thermoplastic mixtures can be used, or . in the use of additional solvents, which must be removed again and worked labor- and energy-intensive and health and pollute the environment.

The object of the present invention was to find a process for producing fiber-reinforced thermoplastic webs with good mechanical properties that should reach values ​​of at least about 25% of the measured longitudinally values ​​also in the transverse direction while eliminating the disadvantages of the known methods. In particular, a good wetting of the fiber reinforcement, even when using any thermoplastics should be possible without additional diluent.

The solution of the object has been found that thermoplastic and fiber reinforcement will be used both in the form of UD-filaments as well as in the form of a film or as nonwoven, woven fabric or chopped fibers.

The invention accordingly provides a process for the continuous production of fiber-reinforced thermoplastic webs, which is characterized in that UD-filaments of glass, carbon, aramide, ceramic or metal or textile fibers or mixtures thereof, UD-filaments of a thermoplastic, a melt or a film of the thermoplastic as well as additional reinforcing fibers at a temperature which is above the melting point of the thermoplastic and are pressed together at pressures bar from 1.2 to 40.

When UD filaments both monofilaments and rovings are also suitable. In the case of rovings, it is advantageous, and never become the filament bundle prior to entry into the continuous press in individual threads to a uniform distribu tion of the filaments of the different materials to achieve. The splicing of the single strands can be done for example by means of compressed air or by passing the rovings via a spreader.

According Polyam can all thermoplastics, which can be processed into fibers, such. As polyolefins, ide, polyesters, polycarbonates, polyurethanes, polyphenylene oxide, polyphenylene sulfide, polysulfone, polyether, polyamide and polyether are used. Preferred thermoplastics are polypropylene, polyamides such as nylon 6 or nylon 6,6 and polyethylene terephthalate. Be particularly favorable proven polypropylene, among both homopolymers and copolymers are to be understood, for example, with ethylene or unsaturated carboxylic acids. The zusx.

The addition mitverpreßten reinforcing fibers consist of glass, carbon, aramid, ceramic, metal or textile fibers or mixtures thereof. They can be present as a needled or quilted random nonwoven web, a woven fabric or as chopped fibers, for example in the form of fiber mats, z. B.. Among textile fibers and yarns, both natural fibers, such. As jute, as well as synthetic fibers having a higher melting point or decomposition point than that of the thermoplastic matrix are to be understood. The additional reinforcing fibers are used preferably in an amount of 20 - 70 wt% is used, based on the total amount of glass, carbon, aramid, ceramic, metal, textile filaments and additional reinforcing fibers..

It proves to be advantageous if UD filaments and additional reinforcing fibers of glass, carbon, aramid or mixtures thereof are included in the composite. The finished composite typically has a content of reinforcing fibers of a total of about 15 - 60 vol%. This corresponds in the case of glass fibers, a content of about 20-75 wt.%.

The preparation of the fiber-reinforced thermoplastic webs is carried out on a continuous press, for example a double band press, which uniformly across the width distributed thermoplastic UD-filaments, the UD-filaments of glass, carbon, aramide, ceramic or metal or textile fibers or mixtures thereof, a thermoplastic melt, for example, a freshly extruded melt film or a thermoplastic film, and additional reinforcing fibers are continuously fed, for example in the form of a random nonwoven mat. In the first, heated part of the double belt press the supplied thermoplastic melts at temperatures which are usually 20 to 80 ° C above its melting point, complete, with the UD-filaments of glass, carbon, aramide, ceramic or metal or textile fibers and the additional fiber reinforcement be impregnated between the belts of the press under pressure with molten thermoplastic. In a subsequent cooling zone, the composite formed, also cooled between the belts of the press under pressure and thereby to solidify. The obtained fiber-reinforced thermoplastic webs usually have a thickness of 1 to 10 mm.

Another object of the invention are fiber-reinforced thermoplastic webs that are prepared according to the methods described above. The fiber reinforced thermoplastic sheets are mainly used as starting material for producing moldings by hot pressing. About 20 to 80 ° C above the melting point of the thermoplastic material heated sheets or panels are thereby inserted into heated molds and pressed at temperatures of about 70 to 120 ° C and pressures of 1 to 100 bar.

Comparative Example C1

A polypropylene (PP) homopolymer with an MFI of 200 g / 10 min (measured according to ISO R 1133, Procedure 12, 230 ° C, 2.16 kg), 0.6 wt.% Long-term stabilizer (Irganox 1010, Ciba-Geigy ), 0.2 wt.% processing stabilizer (Irgaphos PEPQ, Ciba-Geigy) and 2 wt.% carbon black (Euthylenschwarz BASF) were melted in an extruder, than 1.3 m wide film having a basis weight of 2.7 kg / m² extruded from a slot die and / fed into a double belt press with 4 m min speed. At the same time the double band press (0.014 mm diameter, Type EC 14 -2400 2400 tex, - P 365 (300), Gevetex) were above the melt film 375 E-glass yarns per meter, as well as up and down depending on a fiber-entangled non-woven mat with a basis weight of 450 g / m² (Type U 101, Gevetex) supplied. At a temperature of 200 ° C and a pressure of 5 bar a 3.7 mm thick was, 1.3 m wide, glass fiber reinforced PP sheet with a glass content of 40 wt.%, A PP-content of 60 wt.% And a basis weight of 4.5 kg / m² obtained. Flexural modulus (DIN 53457), flexural strength (DIN 53453) and impact strength of the composite after molding at 70 ° C mold temperature and 100 bar are summarized in Table 1 below.

example 2

Analogously to Example V1 a glass fiber reinforced PP web was measured with a PP-content of also 60 wt.% Was prepared, except that 50 wt.% PP as a melt film as in Example 1, but from a PP having a MFI of 50 g / 10 min (Daplen^(R) US 105A by Petrochemicals Danubia) having a basis weight of 2.25 kg / m² and 10 wt.% PP in the form of rovings 62 PP per meter, each with 7300 tex (Asota^(R) Einzelfadentiter 17 dtex), which was fed together with the glass fiber rovings of the press, were used. The properties of the 3.7 mm thick laminate are summarized in Table 1 below.

Examples: 3 - 6

Analogously to Example 2% PP were glass fiber reinforced PP-webs with 60 wt., But replacing the proportion of PP, which was varied as a melt film and the proportion of PP, which was used in the form of PP-rovings, according to the amounts listed in Table 1 , In Example 6, the entire 60 were wt.% PP employed in the form of rovings 370 PP per m (each 7300 tex). The properties of 3.7 mm thick composites are summarized in Table 1 below.

Example V7:

Analogously to Example V1 a fiber-reinforced PP web was produced, with the difference that from Daplen^(R)US 105A (MFI = 50 g / 10 min) A melt film having a basis weight of 2.59 kg / m² was made and that, as a fiber reinforcement two fiber-entangled nonwoven mats (U 101) having a basis weight of 200 g / m² and 925 carbon fiber rovings per 1 m (800 tex, HTA-7-12000, Toho rayon) were used. There% PP was a fiber-reinforced PP web having 10 wt.% Glass fibers, 20 wt.% Carbon fibers and 70 wt. Obtained whose mechanical properties are summarized in Table 2.

Example 8:

Analogously to Example C7 was a reinforced with carbon and glass fibers PP PP sheet having a content of also 70 wt.% Prepared, except that 40 wt.% PP in the form of a melt film having a basis weight of 1.5 kg / m² and 30 wt.% PP in the form of 152 PP roving per m (7300 tex, 17 dtex Einzelfadentiter) were used. The properties are summarized in Table 2 below.

Example C9:

Analogously to Example V1 a fiber-reinforced PP web was produced, with the difference that from Daplen^(R) US 105A (MFI = 50 g / 10 min) A melt film / m² was prepared with a basis weight of 2.45 kg, and that as a fiber reinforcing two fiber-entangled nonwoven mats (U 101) having a basis weight of each 175 g / m² and 3000 strands per m of aramid continuous fibers (Kevlar^(R) 49, 235 tex, Du Pont) were used. There% PP was a fiber-reinforced PP web having 10 wt.% Glass fibers, 20 wt.% Aramid fibers and 70 wt. Obtained whose properties are zuammengestellt in Table 3.

Example 10:

Analogously to Example V9 was reinforced with aramid and glass fibers PP PP sheet having a content of also 70 wt.% Prepared, but only 40 wt.% PP in the form of a melt film (1.4 kg / m²) and 30 % PP in the form of 145 PP strands per m (7300 tex) were used by weight.. The properties are summarized in Table 3 below.

From the examples it can be seen that with the additional use of PP-rovings the mechanical properties of the composites were improved. <tables id="tabl0001" num="0001"><table frame="all"><title>Table 1</title><tgroup cols="6" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="26.25mm" /><colspec colnum="2" colname="col2" colwidth="26.25mm" /><colspec colnum="3" colname="col3" colwidth="26.25mm" /><colspec colnum="4" colname="col4" colwidth="26.25mm" /><colspec colnum="5" colname="col5" colwidth="26.25mm" /><colspec colnum="6" colname="col6" colwidth="26.25mm" /><thead valign="top"><row><entry namest="col1" nameend="col6" align="left">Glass fiber reinforced PP sheeting</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col6" align="justify">(60 wt.% PP, 20 wt.% Glass mat, 20 wt.% Glass rovings)</entry></row></tbody></tgroup><tgroup cols="6" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="26.25mm" /><colspec colnum="2" colname="col2" colwidth="26.25mm" /><colspec colnum="3" colname="col3" colwidth="26.25mm" /><colspec colnum="4" colname="col4" colwidth="26.25mm" /><colspec colnum="5" colname="col5" colwidth="26.25mm" /><colspec colnum="6" colname="col6" colwidth="26.25mm" /><thead valign="top"><row><entry namest="col1" nameend="col1" /><entry namest="col2" nameend="col2" align="center">PP melt (wt.%)</entry><entry namest="col3" nameend="col3" align="center">PP roving (wt.%)</entry><entry namest="col4" nameend="col4" align="center">Flexural modulus of elasticity (N / mm²)</entry><entry namest="col5" nameend="col5" align="center">Bending strength (N / mm²)</entry><entry namest="col6" nameend="col6" align="center">Impact strength (kJ / m²)</entry></row><row><entry namest="col1" nameend="col1" /><entry namest="col2" nameend="col2" align="center">MFI = 50</entry><entry namest="col3" nameend="col3" align="center">MFI = 15</entry><entry namest="col4" nameend="col4" align="center">longitudinal / transverse</entry><entry namest="col5" nameend="col5" align="center">longitudinal / transverse</entry><entry namest="col6" nameend="col6" align="center">longitudinal / transverse</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">V1</entry><entry namest="col2" nameend="col2" align="right">60 *</entry><entry namest="col3" nameend="col3" align="right">0</entry><entry namest="col4" nameend="col4" align="right">6000/5000</entry><entry namest="col5" nameend="col5" align="right">130/50</entry><entry namest="col6" nameend="col6" align="left">140/40</entry></row><row><entry namest="col1" nameend="col1" align="left">2</entry><entry namest="col2" nameend="col2" align="right">50</entry><entry namest="col3" nameend="col3" align="right">10</entry><entry namest="col4" nameend="col4" align="right">8500/6000</entry><entry namest="col5" nameend="col5" align="right">150/90</entry><entry namest="col6" nameend="col6" align="left">without break</entry></row><row><entry namest="col1" nameend="col1" align="left">3</entry><entry namest="col2" nameend="col2" align="right">40</entry><entry namest="col3" nameend="col3" align="right">20</entry><entry namest="col4" nameend="col4" align="right">9000/5500</entry><entry namest="col5" nameend="col5" align="right">150/90</entry><entry namest="col6" nameend="col6" align="left">without break</entry></row><row><entry namest="col1" nameend="col1" align="left">4</entry><entry namest="col2" nameend="col2" align="right">30</entry><entry namest="col3" nameend="col3" align="right">30</entry><entry namest="col4" nameend="col4" align="right">10000/6000</entry><entry namest="col5" nameend="col5" align="right">145/90</entry><entry namest="col6" nameend="col6" align="left">without break</entry></row><row><entry namest="col1" nameend="col1" align="left">5</entry><entry namest="col2" nameend="col2" align="right">10</entry><entry namest="col3" nameend="col3" align="right">50</entry><entry namest="col4" nameend="col4" align="right">8500/6000</entry><entry namest="col5" nameend="col5" align="right">130/80</entry><entry namest="col6" nameend="col6" align="left">without break</entry></row><row><entry namest="col1" nameend="col1" align="left">6</entry><entry namest="col2" nameend="col2" align="right">0</entry><entry namest="col3" nameend="col3" align="right">60</entry><entry namest="col4" nameend="col4" align="right">8500/6000</entry><entry namest="col5" nameend="col5" align="right">180/90</entry><entry namest="col6" nameend="col6" align="left">230/60</entry></row></tbody></tgroup><tgroup cols="6" colsep="0" rowsep="0"><colspec colnum="1" colname="col1" colwidth="26.25mm" /><colspec colnum="2" colname="col2" colwidth="26.25mm" /><colspec colnum="3" colname="col3" colwidth="26.25mm" /><colspec colnum="4" colname="col4" colwidth="26.25mm" /><colspec colnum="5" colname="col5" colwidth="26.25mm" /><colspec colnum="6" colname="col6" colwidth="26.25mm" /><tbody valign="top"><row><entry namest="col1" nameend="col6" align="justify">* MFI = 200 g / 10 min</entry></row></tbody></tgroup></table></tables><tables id="tabl0002" num="0002"><table frame="all"><title>Table 2</title><tgroup cols="6" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="26.25mm" /><colspec colnum="2" colname="col2" colwidth="26.25mm" /><colspec colnum="3" colname="col3" colwidth="26.25mm" /><colspec colnum="4" colname="col4" colwidth="26.25mm" /><colspec colnum="5" colname="col5" colwidth="26.25mm" /><colspec colnum="6" colname="col6" colwidth="26.25mm" /><thead valign="top"><row><entry namest="col1" nameend="col6" align="left">Carbon fiber reinforced PP sheeting</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col6" align="justify">(70 wt.% PP, 10 wt.% Glass mat, 20 wt.% Carbon rovings)</entry></row><row><entry namest="col1" nameend="col1" align="right">V7</entry><entry namest="col2" nameend="col2" align="right">70</entry><entry namest="col3" nameend="col3" align="right">0</entry><entry namest="col4" nameend="col4" align="right">12000/3200</entry><entry namest="col5" nameend="col5" align="right">200/50</entry><entry namest="col6" nameend="col6" align="right">150/30</entry></row><row><entry namest="col1" nameend="col1" align="right">8th</entry><entry namest="col2" nameend="col2" align="right">40</entry><entry namest="col3" nameend="col3" align="right">30</entry><entry namest="col4" nameend="col4" align="right">14000/3400</entry><entry namest="col5" nameend="col5" align="right">220/80</entry><entry namest="col6" nameend="col6" align="right">160/40</entry></row></tbody></tgroup></table></tables><tables id="tabl0003" num="0003"><table frame="all"><title>Table 3</title><tgroup cols="6" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="26.25mm" /><colspec colnum="2" colname="col2" colwidth="26.25mm" /><colspec colnum="3" colname="col3" colwidth="26.25mm" /><colspec colnum="4" colname="col4" colwidth="26.25mm" /><colspec colnum="5" colname="col5" colwidth="26.25mm" /><colspec colnum="6" colname="col6" colwidth="26.25mm" /><thead valign="top"><row><entry namest="col1" nameend="col6" align="left">Aramid PP sheeting</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col6" align="justify">(70 wt.% PP, 10 wt.% Glass mat, 20 wt.% Aramidfaserrovings)</entry></row><row><entry namest="col1" nameend="col1" align="left">V9</entry><entry namest="col2" nameend="col2" align="right">70</entry><entry namest="col3" nameend="col3" align="right">0</entry><entry namest="col4" nameend="col4" align="right">9000/2800</entry><entry namest="col5" nameend="col5" align="right">150/50</entry><entry namest="col6" nameend="col6" align="right">120/50</entry></row><row><entry namest="col1" nameend="col1" align="left">10</entry><entry namest="col2" nameend="col2" align="right">40</entry><entry namest="col3" nameend="col3" align="right">30</entry><entry namest="col4" nameend="col4" align="right">12000/3500</entry><entry namest="col5" nameend="col5" align="right">170/70</entry><entry namest="col6" nameend="col6" align="right">140/60</entry></row></tbody></tgroup></table></tables>