EXTRUSION HEAD FOR PLASTIC MATERIALS

TECHNICAL FIELD

The present invention concerns an extrusion head for plastic materials .

In particular, this extrusion head can be used for the coextrusion of two materials having ^■ different chemical- physical and/or colorimetric characteristics.

BACKGROUND ART

It is known that very thin strips of plastic material, known as tapes, are used in the creation of artificial.

In order that artificial grass approximates to natural grass in a credible manner, from a visual standpoint, it is important that the tapes do not all have the same colour.

For example, each tape can have a first face with a first colour (e.g. dark green), and a second face with a second colour (e.g. light green) .

As shall be seen, by means of the extrusion head, the subject of the present invention, it is possible to obtain tapes having the colouring of a first material, the colouring of a second material, or a first face coloured according to a first material and a second face with the colour of a second material, by simply changing a distribution plate.

DISCLOSURE OF INVENTION

Thus, according to the present invention, an extrusion ^' head is embodied in accordance with the enclosed claims.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention shall now be described with reference to

the enclosed drawings, which illustrate non-limitative examples of embodiment, where:

- Figure 1 illustrates a section A-A of a first embodiment of an extrusion head, the subject of the present invention, - Figure 2 shows a view C-C of a detail of the extrusion head in Figure 1,

- Figure 3 illustrates a section B-B of the extrusion head shown in Figures 1 and 2 ,

- Figure 4 shows a view D-D of a detail of the extrusion head illustrated in Figures 1, 2 and 3,

- Figure 5 illustrates a view E-E of a detail of the extrusion head illustrated in Figures 1, 2, 3 and 4,

- Figure 6 shows a section F-F of a second embodiment of an extrusion head, the subject of the present invention, - Figure 7 illustrates a view G-G of a detail of the extrusion head in Figure 6,

- Figure 8 shows a view H-H of a detail of the extrusion head illustrated in Figures 6 and 7,

- Figure 9 illustrates a view I-I of a detail of the extrusion head illustrated in Figures 6, 7 and 8,

- Figure 10 shows a section L-L of a third embodiment of an extrusion head, the subject of the present invention,

Figure 11 illustrates a view M-M of a detail of the extrusion head in Figure 10, - Figure 12 shows a view N-N of a detail of the extrusion head illustrated in Figures 10 and 11, and

Figure 13 illustrates a view 0-0 of a detail of the extrusion head illustrated in Figures 10, 11 and 12.

BEST MODE FOR CARRYING OUT THE INVENTION

In Figures 1, 2, 3, 4 and 5, reference numeral 100 indicates, in its entirety, a first embodiment of an extrusion head for plastic materials, the subject of the present invention.

The extrusion head 100 comprises, from the top downwards:

a spacer element 101 a first distribution plate 102, a second distribution plate 103, a third distribution plate 104, a preform die 105, and a die 106 packed one on top of the other and held together by clamping means (e.g. clamping screws) that are not shown in the enclosed figures so as not to compromise legibility.

Representations of the electrical resistances that serve to heat the extrusion head 100 to keep the plastic materials to be extruded in the fluid state have also been omitted from the enclosed drawings .

The various elements packed one on top of the other are substantially symmetrical with respect to a plane, which is traced on the drawing sheet as axis (X) (Figure 2) .

The spacer element 101 is provided with two inlet channels for two different plastic materials. These different plastic materials can have different chemical-physical characteristics and/or different colours.

Entering into greater detail, a duct 107a having a respective longitudinal axis of symmetry (A) and a duct 108a having a respective longitudinal axis of symmetry (B) , have been created in the substantially parallelepipedal spacer element 101.

The ducts 107a-108a are the terminal portions of the feed channels (not shown) of two different plastic materials in the semi-liquid state.

As shall be better seen in the following, duct.107a is able to

convey a first plastic product having, for example, a first colour, while a second plastic product having, for example, a second colour, flows through the second duct 108a.

In series with duct 107a there is a duct 107b made in the first distribution plate 102, such that the set of the two ducts 107a-107b in series form a feed channel 107 (with axis (A)) for the first product.

Similarly, in series with duct 108a there is a second duct 108b, made in the first distribution plate 102, and a third duct 108c obtained in the third distribution plate 103. the set of ducts 108a-108b-108c in series form a feed channel 108 (with axis (B)) in which the second product flows, which, as already mentioned, generally has different chemical-physical and/or colorimetric characteristics from the first product.

A first distribution network 109 for the first product is made in an interface INTFl between the first distribution plate 102 and the second distribution plate 103. This first distribution network 109 has a U-shape, with a branch 109a transversal to axis (X) and two branches 109b-109c parallel to the same axis

(X) •

Furthermore, between the second distribution plate 103 and the third distribution plate 104, there is an interface INTF2 in which there is a second distribution network 110 for the first product including two branches HOa-IlOb both parallel to axis

(X) •

Similarly to that seen above, a third distribution network 111, always for the first product, is allocated in an interface INTF3 between the third distribution plate 104 and the preform die 105.

In turn, the third distribution network 111 includes two branches Ilia, 111b.

Branch Ilia (Figure 4) comprises a duct Ilia* parallel to . axis (X) and a plurality of ducts Ilia** perpendicular to the same axis (X) . Each duct Ilia** terminates in a respective extrusion outlet '112 (Figure 5) from which the first finished extruded product emerges. The extrusion outlet 112 has the shape of a slit parallel to axis (A) and affects the preform die 105 and the die 106.

Similarly, branch 111b comprises a duct 111b* parallel to axis (X) and a plurality of ducts 111b** perpendicular to the same axis (X) . Each duct 111b** terminates in a respective extrusion outlet 112 from which, the finished extruded product emerges .

As shown, always in Figures 1, 2, 3, 4 and 5, the first distribution network 109 for the first product is connected to the second distribution network 110 for the same product via a plurality of vertical conduits 113, parallel to axis (A) (Figure 1) .

Furthermore, a plurality of conduits 114, these also vertical and parallel to axis (A) , is provided between the second distribution network 110 for the first product and the third distribution network 111. Each conduit 114 is the continuation of the respective conduit 113.

The feed channel 108 for the second product terminates in a fourth distribution network 115 situated in the interface INTF2 between the second distribution plate 103 and the third distribution plate 104.

The fourth distribution network 115 for the second product is

U-shaped and is identical to the first distribution network 109. This fourth distribution network 115 therefore has a branch 115a transversal to axis (X) and two branches 115b-115c parallel to the same axis (X) .

Furthermore, branches 115b and 115c of the fourth distribution network 115 for the second product are parallel to branches 110a and 110b of the second distribution network 110.

Moreover, a fifth distribution network 116, always for the second product, is situated in the interface INTF3 between the third distribution plate 104 and the preform die 105.

In turn, the fifth distribution network 116 includes two branches 11βa, 116b.

Branch 116a comprises a duct 116a* parallel to axis (X) and a plurality of ducts 116a** perpendicular to the same axis (X) . Each duct 116a** terminates in a respective extrusion outlet 112 from which the second finished extruded product emerges.

Similarly, branch 116b comprises a duct 116b* parallel to axis (X) and a plurality of ducts 116b** perpendicular to the same axis (X) . Each duct 116b** terminates in a respective extrusion outlet 112 from which the finished extruded product emerges .

In other words, each duct Ilia** (in which the first product is extruded) faces a respective duct 116a** (in which the second product is extruded) and each duct 111b** (in which the first product is extruded) finds itself facing a respective duct 116b** (through which the second product is extruded) .

In addition, each pair formed by ducts Ilia** and 116a**, and, respectively, by ducts 111b** and 116b** flow into the same

respective coextrusion outlet 112 for the two materials, so as to obtain, for example, tape with different coloured faces.

A plurality of conduits 117, these also vertical and parallel to axis (B) , is provided between the fourth distribution network 115 for the second product and the fifth distribution network 116.

It should be noted that the outlet 112 in the first embodiment shown in Figures 1, 2, 3, 4 and 5 is the same for the two products to be extruded.

In this way, as they are coextruded in the outlets 112, the two products form tapes, each having two faces with different properties, such as different colours for example.

The problem of simultaneously coextruding two plastic materials having different characteristics using the same outlets 112 is thus resolved in a simple and inspired manner.

In the second embodiment shown in Figures 6, 7, 8 and 9, a third distribution plate 204, different from the distribution plate 104 previously described with reference to the first embodiment illustrated in Figures 1, 2, 3, 4 and 5, has been adopted in an extrusion head 200.

In Figures 6, 7, 8 and 9, the first figure of the reference numbers has been changed to "2" because they substantially indicate the same elements regarding the first embodiment shown in Figures 1, 2, 3, 4 and 5.

In fact, in this case, a third distribution network 211

(Figure 8) for a first product includes, in turn, two branches

211a-211b. Branch 211a comprises a duct 211a* parallel to axis (X) and a plurality of ducts 211a** perpendicular to the same

axis (X) that are not equally spaced out between each other. Each duct 211a** terminates in a respective extrusion outlet 212* or 212**.

Incidentally, it should be noted that the extrusion outlets in which the second product is also coextruded with the system seen in the first embodiment are identified by reference number 212*, while 212** indicates the extrusion outlets in which only the first product is extruded.

Similarly, branch 211b comprises a duct 211b* parallel to axis (X) and a plurality of ducts 211b** perpendicular to the same axis (X) that are not equally spaced out between each other. Each duct 211b** terminates in a respective extrusion outlet 212* or 212** from which the finished extruded product emerges .

Regarding the second plastic product, the fifth distribution network 216 has two branches 21βa and 216b. Branch 216a comprises a duct 216a* parallel to axis (X) and a plurality of ducts 216a** perpendicular to the same axis (X) that are not equally spaced out between each other.

Each duct 216a** terminates in a respective coextrusion outlet 212*, or terminates in a respective outlet 212*** from which only the second finished extruded product emerges .

As can be noted from observation of Figure 8, outlets 212**

(for extrusion of just the first product) are inserted in between outlets 212*** (for extrusion of just the second product) .

Similarly, branch 216b comprises a duct 216b* parallel to axis

(X) and a plurality of ducts 216b** perpendicular to the same axis (X) . Each duct 216b** terminates in a respective

coextrusion outlet 212* or 212***, or terminates in a respective outlet 212*** from which only the second finished extruded product emerges .

Outlets 212** (for extrusion of just the first product) are inserted in between outlets 212*** (for extrusion of just the second product) .

Incidentally, it should be noted that the extrusion outlets in which both products are simultaneously coextruded with the system seen in the first embodiment are identified by reference number 212*, while tapes made with just the first product emerge from extrusion outlets 212** and outlets 212*** are the extrusion outlets in which only the second product is extruded.

Furthermore, the coextrusion outlets 212* of both products are positioned all in a row, one behind the other, while the extrusion outlets 212** for just the first product are inserted in between the extrusion outlets 212*** for just the second product.

Consequently, there is a first series of coextruded tapes having faces made with two different products, a second series of tapes made only with the first product and a third series of tapes obtained by extrusion of just the second product.

In the third embodiment shown in Figures 10, 11, 12 and 13, a third distribution plate 304, different from the third distribution plate 104 previously described with reference to the first embodiment illustrated in Figures 1, 2, 3, 4 and 5, has been adopted in an extrusion head 300. Furthermore, the third distribution plate 304 is also different from the third distribution plate 204 utilized in the second embodiment of present invention and described with reference to Figures 6,

7, 8 and 9.

In Figures 10, 11, 12 and 13, the first figure of the reference numbers has been changed to "3" because they substantially indicate the same elements regarding the first embodiment shown in Figures 1, 2, 3, 4 and 5, and the second embodiment illustrated in Figures 6, 7, 8 and 9.

In the third embodiment (Figures 10, 11, 12 and 13), extrusion outlets 312** alternating with extrusion outlets 312***

(Figures 12 and 13) are provided in the manner seen for the second embodiment. As the solution adopted in the third embodiment is substantially identical to part of that described in the second embodiment with regard to extrusion outlets 212** and 212***, to not make the present description overlong, please refer to the description concerning the second embodiment shown in Figures 6, 7, 8 and 9.

It is also important to note that one of the most interesting characteristics of the extrusion head 100, 200 and 300, the subject of the present invention, consists in the fact that simply changing the third distribution plate 104 (Figure 1) , 204 (Figure 6) and 304 (Figure 10) results in producing tapes with different characteristics.

The main advantage of the extrusion head, the subject of the present invention, consists in its extreme versatility, due to the fact that by simply changing a distribution plate for the plastic materials in the semi-liquid state, tapes are obtained that have different characteristics and which can be used, for example, to create artificial grass with a very pleasing visual effect, and in all those cases where dual colouring of the same monofilament is required. Furthermore, considering that the monofilaments are wound onto reels, with the system in question it is possible to produce reels with different

colours or combinations of threads with colour A and colour B in a single winding operation, avoiding further production steps that without the aid of the head in question, must instead be carried out. However, neither should the high flexibility of the system be overlooked, which ensures unlimited choice in the ratio of the number of threads with different colours and the winding method.