EP1853413A1

EP1853413A1 - Method for molding a profiled weatherstrip on a glazing

Info

Publication number: EP1853413A1
Application number: EP05739456A
Authority: EP
Inventors: Guy Leclercq; Thierry Thuillier; Fabrice Ducreuzot
Original assignee: Saint Gobain Glass France SAS; Compagnie de Saint Gobain SA
Current assignee: Saint Gobain Glass France SAS; Compagnie de Saint Gobain SA
Priority date: 2005-03-03
Filing date: 2005-03-03
Publication date: 2007-11-14
Also published as: JP4603053B2; BRPI0520089B1; CN101171115B; CA2599845A1; KR101191260B1; EA010846B1; US20080241470A1; CN101171115A; CA2599845C; MX2007010663A; BRPI0520089A2; KR20070116593A; WO2006092472A1; EA200701876A1; JP2008531346A

Abstract

The invention concerns a method for molding a profiled weatherstrip (1) made of plastic material consisting of several constituents, in particular a polyurethane-based material, on at least a peripheral portion of a glazing (2) using at least one injecting head (3), wherein said material ejected through an outlet (4) of the injecting head (3) penetrates into a molding cavity (5) to form said molded profiled weatherstrip. The invention is characterized in that the material ejected through the outlet (4) of the injecting head (3) penetrates directly into said molding cavity (5).

Description

METHOD FOR MOLDING A PROFILE HOSE ON A GLAZING

The present invention relates to a method of molding a profiled casing made of a plastic material formed of several components, in particular a polyurethane-based material, on at least one peripheral portion of a glazing using at least one injection head, wherein said material ejected from an outlet of the injection head then enters a mold cavity to form said molded shaped casing.

The present invention also relates to the device for implementing the method and the glazing obtained by the implementation of the method.

The molding of plastics formed from several components has been known for a long time and is used to form, for example by the so-called "encapsulation" technique, profiled polyurethane hoses on the peripheral edge of glazing and in particular of automotive glazing, in particular by the implementation of the so-called "reaction in the injection mold" or RIM (Reaction Injection Molding) technology.

In order for the constituents, in this case at least the polyol and the isocyanate, to mix well and for the final material forming the seal to have a homogeneous appearance without spot defects of the bubble-like type, asperities, the person skilled in the art has always considered that it was necessary for the material to pass through an intermediate means of the distribution channel or mixing cavity and / or homogenization, located between the outlet orifice of the injection head and the mold cavity. itself that allows to realize the molded hose.

This intermediate means was intended to allow the reactive mixture to flow into the mold in a laminar manner and without forming bubbles.

This mixing cavity and / or homogenization, located before the molding cavity by considering the direction and direction of injection of the material is sometimes called "injection cone" or "injection blade" or "carrot injection "or

"Static mixer". This cavity is sometimes provided with a throttling portion, that is to say a portion where its section is reduced.

When the injected material is a thermosetting material, all the material present in the intermediate means must be discarded because it can not be recycled. Now the quantity The amount of material present in this intermediate means, in particular when a mixing and homogenizing effect is achieved, may represent up to one-third of the total amount of material injected into the mold cavity for the manufacture of the molded casing. In addition, the connection zone between the material in the intermediate means and the material forming the molded casing, sometimes called the "injection threshold" of the product, must be subjected to a finishing step by cutting the burrs and then Sanding the cut areas to hide the difference in appearance of the part in this area, because the break between the two parts of the material is never smooth and straight. This step being difficult to automate, its realization by hand generates an additional cost during manufacture.

This injection threshold being furthermore sometimes positioned at the end of a lip of the profiled hose, this step must be carried out carefully so as not to damage the lip during the cutting of the burrs and the sanding. Furthermore, the cavity for mixing and / or homogenization is generally hollowed out in one of the constituent parts of the mold. The presence of this cavity thus makes more complex the study prior to the production of the mold and the manufacture of the mold. The presence of this cavity and generates additional cost during the design of the mold. In particular, for the molding of complex shapes, it is sometimes necessary to make the mixing and / or homogenization cavity with mold elements, or "wedges", which are driven during demolding of a translation movement and or rotation to allow the release of the material contained in the cavity of the intermediate means. Such complex configurations obviously generate a significant additional cost during the study prior to the production of the mold and during the manufacture of the mold. These achievements also complicate maintenance of the mold because their malfunction can cause losses of material and thus reduce the quality of the material constituting the profiled hose.

Many books are available to the skilled person to enable him to size the intermediate means necessary according to the production parameters.

Those skilled in the art also know from European Patent Application No. EP 629 482 an injection channel of a particular type. The object of the invention is to overcome the disadvantages of the prior art by proposing a multi-component material injection process which no longer requires the presence of an intermediate means as defined above and whose means for to implement it are thus simpler and less expensive to design and use.

The inventors have found that, surprisingly, it was quite possible to inject the material directly into the molding cavity, without passing the material through an intermediate means.

The present invention thus relates in its broadest sense to a method of molding a shaped casing made of a plastic material formed of several components, in particular a polyurethane-based material, on at least one peripheral portion of a glazing unit with at least one injection head, wherein said material ejected from an outlet of the injection head then enters a mold cavity to form said molded shaped casing, characterized in that the material ejected by said outlet of the injection head penetrates directly into said mold cavity.

This molding cavity is delimited by molding walls between which the injected material spreads as well as the glazing on which the casing will adhere.

Thus the plastic material formed of several components and ejected by said outlet orifice of the injection head does not pass through an intermediate means of the distribution channel or mixing cavity, located between said outlet orifice and said mold cavity. The distance between the exit orifice of the injection head and the surface of the adjacent glazing on which the shaped casing is formed corresponds to the height of the casing profiled at this level on the finished product; no more matter is lost.

For the purposes of the present invention, the term "multi-component plastics material" means that the plastic itself in order to crosslink requires the mixing and reaction of several monomers with one another; the chosen expression thus does not cover a plastic material which would need one or more polymerization agent (s) in a low or very low proportion (in a proportion of less than 10%), for example a catalyst and / or a accelerator.

The material used for the implementation of the invention may comprise, in addition to the multi-component plastics material, reinforcement elements such as example of glass fibers. In the case of a plastic material based on polyurethane, these reinforcing elements are added in a known manner to the polyols.

The material is preferably ejected by said outlet orifice at a wall of said molding cavity, i.e. the average plane of the outlet orifice is substantially coincidental in the average plane of the wall at this place.

In addition, the material is preferably ejected by said outlet orifice in a flow substantially perpendicular to the plane of the adjacent glazing.

The present invention also relates to a device for molding a profiled casing made of a plastic material formed of several components, in particular a polyurethane-based material, on at least one peripheral portion of a glazing unit, said device having at least one injection head having an outlet port through which the material is ejected and a molding cavity for forming said molded profile casing, characterized in that said outlet port of the injection head opens directly into said cavity molding.

Thus, this device does not include intermediate means of the distribution channel type or mixing cavity, located between said outlet port and said mold cavity. The outlet orifice is preferably disposed flush in a wall of said mold cavity. However, the outlet orifice according to the invention may also be arranged slightly protruding with respect to the wall of the molding cavity at this point (of the order of a few millimeters at the most, not more than 5 mm), but this will then result in a hollow mark on the final product; the outlet orifice according to the invention can also be arranged slightly recessed with respect to the wall of the molding cavity at this point (of the order of a few millimeters at the most, not more than 5 mm), but this will cause then a prominent mark on the final product.

The outlet port of the injection head is provided with a movable valve which is open during the injection of material to allow the material to flow into the mold cavity and is closed the rest of the time.

Thus, no recovery of the shaped casing is necessary because the rupture at the connection zone between the material remained in the injection head and the material forming the molded casing is clear, thanks to the action of the movable valve. Traditionally, the injection head is disposed immobile next to the mold elements, at least one of which is movable to allow the loading and unloading of the glazing, respectively before and after the molding of the shaped casing because this injection head is complex because several components are mixed therein and recirculation of the components is provided between each material injection period; however, for the implementation of the present invention, the inventors have realized that it is quite possible to have the injection head in a wall of the mold and therefore, if the mold is movable, it It was possible to apply a movement to the injection head during each molding cycle. Thus, in a variant, the injection head of the device according to the invention is integral with a movable mold element.

In a variant also, the outlet orifice of the injection head has a substantially circular section having an axis disposed substantially perpendicular to the adjacent reception plane of the glazing. Thus, if the injection is performed adjacent to a main surface of the glazing, this axis is perpendicular to this main surface of the glazing; if the injection is performed adjacent to the edge of the glazing, the axis of the orifice is then perpendicular to this edge.

The present invention also relates to glazing provided on at least one peripheral portion of a molded profiled casing made of a plastic material formed of several components, in particular a polyurethane-based material, the casing being manufactured by means of process of the invention.

The profiled casing of the glazing according to the invention does not have any marks or traces of deburring, but may include an injection mark at the point where the ejection of the material has been carried out.

This injection mark is preferably located in a section of the profiled hose that will be little or not visible once the glazing mounted.

Advantageously, thanks to the invention, it is thus no longer necessary to provide an intermediate means in the upstream part of the mold, the part situated between the injection head and the molding cavity itself. The design and manufacture of the mold are thus simplified and less expensive.

Advantageously also, thanks to the invention, it avoids the risks incurred in case of poor definition of the intermediate means or poor realization of this one. Indeed, if the intermediate means has not been well studied and finally does not give satisfaction, as it is made in the same room as a part of the molding cavity, if it is necessary to proceed with a recovery, it is necessary remove the mold part of the installation and start the machining, which is long and expensive and requires a complete immobilization of the molding device.

In addition, the connection zone between the exit orifice of the injection head and the material forming the molded casing must no longer be the subject of a finishing step, because this area is smooth and straight. The cost of this finishing step is thus saved. This connection zone is generally provided in a place that is not very visible in the end on the finished part because it remains generally detectable.

The present invention will be better understood on reading the following detailed description of nonlimiting exemplary embodiments and the accompanying figures: FIG. 1 illustrates a simplified bottom view of a molding device of the art prior, on a horizontally oriented glazing, the view being made at the lower surface of the glazing;

• Figure 2 illustrates a sectional view along C-C of Figure 1;

• Figure 3 illustrates the principle of recirculation of the two components of the plastic material for supplying the injection head;

FIG. 4 illustrates a simplified top view of a molding device of the invention, on horizontally oriented glazing, the view being made at the lower surface of the glazing unit; and

FIG. 5 illustrates a sectional view along D-D 'of FIG. 4.

It is specified that the proportions between the various elements represented are not rigorously respected in these figures in order to facilitate their reading.

Figures 1 and 2 illustrate a glazing (2) on which is formed in a known manner a casing (1) shaped plastic polymer formed of several components, here a polyurethane material.

The method of manufacturing the casing (1) is called "encapsulation" because it comprises a step of molding the casing (1) with the aid of a molding device (10) comprising a mold consisting of two hollow molding elements defining a molding cavity (5): an upper molding element (5 ') and a lower molding element (5 "), as can be seen in FIG. these molding elements are generally manufactured by machining a metal block.In general, a molding element, here the lower molding element (5 "), is fixed and the other is movable; however, it is also possible to provide that the two molding elements are movable.

For molding, the multicomponent plastic material is mixed inside an injection head (3) positioned generally at a joint plane of the two molding elements (5 ', 5 ") and is discharged towards the mold through an outlet (4).

Before entering the molding cavity (5) to form the molded shaped casing, the material ejected by the injection head (3) passes through a distribution channel (15) often cylindrical and often partly dug in the element upper molding (5 ') and partly in the lower molding element (5 ").

In Figure 1, the hose (1) is disposed over the entire periphery of the glazing (2), but this hose could quite be positioned only on a part of the periphery of the glazing or on any part of the glazing. For molding, each molding element is closed on the glazing (2) by means of a seal system (7); however, for clarity, only the seal system (7) of the lower molding element (5 ") has been shown.

It is these seal systems that maintain a sufficient pressure inside the mold during the injection of the polymeric material.

These sealing systems also allow, to a certain extent, to "catch up" with the manufacturing tolerances of the glazing, that is to say, to compensate for the deviations that may occur with the nominal ribs of the glazing in the mold. Each seal system constitutes an annular seal, positioned at the periphery of the glazing and has an axis X, oriented here vertically because the injection is performed on a glazing positioned horizontally; however, the X axis can also be oriented horizontally if the injection is operated on a vertically positioned glazing or otherwise oriented. The seal system (7) may be molded, for example, of silicone.

It is recalled here that the injection pressure often approaches a few bars to a few tens of bars, especially for PU-RIM.

The glazing unit (2) may be monolithic glazing, that is to say constituted of a single sheet of material or be multiple glazing, that is to say consisting of several sheets of material between which is inserted at less a layer of adherent material in the case of laminated glazing, or at least one intermediate space in the case of double glazing. The sheets of material may be mineral, in particular glass, or organic, especially plastic.

The glazing (2) can thus be a glazing for a vehicle, in particular a fixed glazing such as a windshield, a side window, a quarter panel or a roof panel. In the case of a vehicle glazing, the glazing generally has at least partially at its periphery an ornamental strip (8), as can be seen in Figure 2. This strip ornamentation generally results from a enamel deposit, made on the inner face of the glazing or on an intermediate side of the glazing for the composite glazing, but it may also result from a partial and / or peripheral coloration of a sheet of material used, in particular a leaf made of organic material. This ornamental strip (8) is made in the version shown under the glazing (2) on the face of the glazing intended to be oriented towards the inside of the vehicle.

The injection head (3) and the principle of the recirculation system of the material outside the injection phases are illustrated in detail in FIG.

The injection head (3) is provided at its distal end with a movable valve (9) which closes the outlet orifice (4) outside the material injection periods.

Thus, when the valve (9) is closed and no plastic material is injected into the mold, each of the components A and B is sucked from a reservoir, circulates inside the head and is returned in its respective tank. There is no contact between components A and B.

It is only during the injection phase of the material into the mold that the two flows back to the respective tanks are interrupted and that both components A and B are in contact inside the injection head, are mixed and are discharged through the outlet (4), the valve (9) being open.

In the prior art, the mixture of the constituents of the injected plastic material is operated in the injection head and the complete homogenization is often obtained at the downstream end of the distribution channel (15). If the mixture produced is not perfect and the injected material presents unacceptable defects, it is necessary to launch an iterative process of optimization of the injection parameters to overcome these defects, or even to redo the mold part which integrates the injection channel. distribution (15). This obviously causes a significant loss of time and therefore money.

Moreover and above all, all the material located in the distribution channel (15) at the time of closure of the valve (9) at the end of the injection cycle is lost and must be discarded.

Figures 4 and 5 illustrate a glazing unit (2) on which is produced according to the invention a casing (1) shaped plastic polymer formed of several components, here polyurethane.

The molding of the casing (1) is carried out by means of a molding device (11) comprising a mold consisting of two hollow molding elements defining a molding cavity (5): an upper molding element (5 ') and a lower molding element (5 "), as can be seen in FIG.

As can be seen, the device according to the invention illustrated in FIGS.

4 and 5 differs from that of the prior art illustrated in FIGS. 1 and 2 in that the material ejected by said outlet orifice (4) of the injection head (3) penetrates directly into said molding cavity (5) , without passing as before by an intermediate means of the distribution channel or mixing cavity, located between said outlet port (4) and said mold cavity (5).

The injection head used here is the same as before, but it is no longer positioned as before: it is now integrated in a molding element, here the lower molding element (5 ") which is here the fixed molding element, so that the material is ejected through the outlet (4) at a wall (6) of the molding cavity (5). In the version of the invention illustrated here, the movable valve (9) which closes the outlet port (4) outside the material injection periods is flush with the wall (6).

There is thus no more material lost in any intermediate means and for productions in large quantities, the economy of realized material is important.

The mixture of the constituents of the injected plastic material is operated in the injection head. If the mixture produced is not perfect and the injected material has unacceptable defects, it is necessary to launch an iterative process for optimizing the injection parameters to overcome these defects.

To complete the mixing of the components, it is possible to provide in the injection head, before the valve (9) considering the direction of injection, a throttling portion, that is to say a portion where the section of the component mixing duct is reduced. In addition, surprisingly, the injection parameters are easily reproducible from one molding to another and when a new series of parts begins, with a different mold shape, if the previously performed injection was correct, even if the amount of injected material changes, it is sufficient to try a few to optimize the new injection and obtain the necessary quality, although there is no intermediate means for the homogenization of the mixture.

The outlet orifice (4) has a substantially circular section having a Z axis disposed substantially perpendicular to the adjacent reception plane of the glazing.

Furthermore, in the case of a vehicle glazing, the glazing generally has at least partially at its periphery an ornamental strip (8). In the version of the invention illustrated here, the injection is carried out on one side of the hose which is not visible from the outside of the vehicle, once the glazing has been mounted so that the circular mark which may have occurred at level of the valve is not visible from the outside of the vehicle, once the glazing is mounted.

In addition, for the same reasons, the injection is carried out on one side of the casing which is behind the ornamental band (8).

The injection could also be carried out in other places: in areas of the glazing that once mounted glazing will be hidden. In the case of a vehicle glazing also, it is possible to position one (or more) insert (s) in the molding element (5 ', 5 ") prior to molding the hose (1), so that the hose incorporates this (or these) insert (s).

This (or these) insert (s) can (or can) be (or) reinforcement insert (s), generally completely integrated to the hose (1), or be (or) insert (s), generally ρroéminent (s) relative to the casing, for fixing the glazing in the bay intended to accommodate it.

The glazing unit (2) as can be seen in FIG. 5 is provided with a casing (1) profiled in a polymeric material having a suitable surface condition, smooth, without asperities or bubbles and does not have any burrs but has an injection mark located where the injection was made. This glazing is then delivered as it is to the customer after being out of the mold. No deburring operation is performed at the outlet of the mold before delivery to the customer.

The present invention is described in the foregoing by way of example. It is understood that the skilled person is able to achieve different variants of the invention without departing from the scope of the patent as defined by the claims.

Claims

A method of molding a profiled casing (1) made of a plastic material formed of several components, in particular a polyurethane-based material, on at least one peripheral portion of a glazing unit (2) at the using at least one injection head (3), wherein said material ejected through an outlet (4) of the injection head (3) then enters a molding cavity (5) to form said casing molded profile, characterized in that the material ejected by said outlet (4) of the injection head (3) penetrates directly into said mold cavity (5).

2. Molding method according to claim 1, characterized in that the material ejected by said outlet orifice (4) of the injection head (3) does not pass through an intermediate means of the type of distribution channel or mixing cavity located between said outlet (4) and said mold cavity (5).

3. Molding method according to claim 1 or claim 2, characterized in that the material is ejected by said outlet (4) at a wall (6) of said mold cavity (5).

4. Molding method according to any one of claims 1 to 3, characterized in that the material is ejected by said outlet orifice (4) in a flow substantially perpendicular to the plane of the adjacent glazing.

5. Device (11) for molding a shaped casing (1) made of a plastic material made of several components, in particular a polyurethane-based material, on at least one peripheral part of a glazing unit (2) , said device comprising at least one injection head (3) having an outlet (4) through which said material is ejected and a molding cavity (5) for forming said molded shaped casing, characterized in that said orifice outlet (4) of the injection head (3) opens directly into said mold cavity (5).

6. Device (11) according to the preceding claim, characterized in that it comprises no intermediate means of the distribution channel or mixing cavity, located between said outlet orifice (4) and said mold cavity (5) .

7. Device (11) according to claim 5 or claim 6, characterized in that said outlet orifice (4) is arranged flush in a wall (6) of said mold cavity (5).

8. Device (11) according to any one of claims 5 to 7, characterized in that the injection head (3) is integral with a movable mold member (5 ').

9. Device (11) according to any one of claims 5 to 8, characterized in that said outlet (4) has a substantially circular section having a Z axis disposed substantially perpendicular to the adjacent reception plane of the glazing.

10. Glazing (2) provided on at least one peripheral portion of a molded profiled hose (1) made of a plastic material formed of several components, in particular a polyurethane-based material, produced by the implementation of the invention. process according to any one of claims 1 to 4.

11. Glazing (2) according to the preceding claim, characterized in that the profiled casing (1) has no mark or trace deburring.

12. Glazing (2) according to claim LO or 11, characterized in that the profiled hose (1) has an injection mark at the place where the ejection of the material has been carried out.

13. Glazing (2) according to the preceding claim, characterized in that said injection mark is located in a section of the profiled hose that will be little or not visible once the glazing mounted.