DE102021132227A1 - Method for applying a masking layer in-situ to an injection molded plastic part - Google Patents

Abstract

The invention relates to a method for applying a masking layer (M) in-situ to an injection-molded plastic part (1), comprising the following steps: providing an injection-molding tool (2) for producing the plastic part (1), the injection-molding tool (2) having at least two tool halves (3, 4) which form a cavity (5) between them, this cavity (5) and the formations of the tool halves (3, 4) specifying the shape of the plastic part (1) to be formed; Application of a masking layer (M) to at least one of the tool halves (3), the application being carried out on that area (6) or on those areas (6) of the tool half (3) which the later section (7) or which the later sections (7) forming or forming the plastic part (1) which is or are to have the masking layer (M); Closing the tool halves (3, 4) and injecting or pouring a flowable plastic (P) forming the plastic part (1) into the cavity (5) of the injection molding tool (2); allowing the plastic (P) to solidify or solidify to form the plastic part (1); Transferring the masking layer (M) to the section (7) or sections (7) of the formed plastic part (1) by the material and / or the structure of the masking layer (M) is selected so that the masking layer (M) a has greater adhesion to the formed plastic part (1) than to the surface of the tool half (3), so that when the plastic part (1) is removed from the injection molding tool (2), the masking layer (M) completely or partially from the tool half (3). is transferred to the section (7) or sections (7) of the plastic part (1) provided for masking.

Description

The present invention relates to a method for applying a masking layer in situ to an injection molded plastic part.

In methods known from the prior art, a masking layer is only applied after it has been produced, for example by spraying or brushing a corresponding masking layer onto the sections of the plastic part to be masked. For this purpose, the plastic parts usually have to be clamped in processing stations, which has a negative effect on the production time of the plastic components in industrial production. In the case of a spray application in particular, there is also the risk that the masking layer will also reach areas that are not intended to be protected. If the plastic components are subsequently painted, this regularly leads to rejects, since the areas that are actually to be painted remain unintentionally free of paint.

The object of the invention is therefore to specify a method for applying a masking layer to an injection-molded plastic part, which can be carried out with fewer method steps than in the prior art and which has a reduced occurrence of incorrect masking.

• - Bereitstellen eines Spritzgusswerkzeuges zur Herstellung des Kunststoffteils, wobei das Spritzgusswerkzeug wenigstens zwei Werkzeughälften aufweist, die zwischen sich eine Kavität ausbilden, wobei diese Kavität und die Ausformungen der Werkzeughälften die Gestalt des auszubildenden Kunststoffteils vorgeben;
• - Aufbringen einer Maskierungsschicht auf wenigstens eine der Werkzeughälften, wobei das Aufbringen auf demjenigen Bereich oder auf denjenigen Bereichen der Werkzeughälfte erfolgt, welcher den späteren Abschnitt oder welche die späteren Abschnitte des Kunststoffteils ausbildet oder ausbilden, der oder die die Maskierungsschicht aufweisen soll oder sollen;
• - Schließen der Werkzeughälften und Einspritzen oder Eingießen eines fließfähigen, das Kunststoffteil bildenden, Kunststoffes in die Kavität des Spritzgusswerkzeuges;
• - Verfestigen oder Erstarren lassen des Kunststoffs, um das Kunststoffteil auszubilden;
• - Übertragen der Maskierungsschicht auf den Abschnitt oder auf die Abschnitte des gebildeten Kunststoffteils, indem das Material und/oder der Aufbau der Maskierungsschicht so gewählt ist, dass die Maskierungsschicht eine größere Anhaftung zu dem gebildeten Kunststoffteil aufweist als zu der Oberfläche der Werkzeughälfte, sodass bei der Entnahme des Kunststoffteils aus dem Spritzgusswerkzeug die Maskierungsschicht ganz oder teilweise von der Werkzeughälfte auf den oder die zur Maskierung vorgesehenen Abschnitt oder Abschnitte des Kunststoffteils übertragen wird.

According to the invention, this object is achieved by a method for applying a masking layer in situ to an injection-molded plastic part, comprising the following steps:

• - Providing an injection mold for producing the plastic part, the injection mold having at least two mold halves which form a cavity between them, this cavity and the formations of the mold halves specifying the shape of the plastic part to be formed;
• - Application of a masking layer to at least one of the tool halves, the application being carried out on that area or on those areas of the tool half which forms or form the later section or sections of the plastic part which is or are to have the masking layer;
• - Closing the mold halves and injecting or pouring a free-flowing plastic forming the plastic part into the cavity of the injection mold;
• - allowing the plastic to solidify or solidify to form the plastic part;
• - Transfer of the masking layer to the section or sections of the plastic part formed, in that the material and/or the structure of the masking layer is selected in such a way that the masking layer adheres better to the plastic part formed than to the surface of the tool half, so that during the Removal of the plastic part from the injection mold, the masking layer is transferred in whole or in part from the mold half to the section or sections of the plastic part provided for masking.

By integrating the step of transferring the masking layer into the manufacturing process (primary forming process) of the plastic part, a subsequent coating process is avoided on the one hand. On the other hand, the masking layer can be formed automatically only on the later section or sections of the plastic part that is or should have the masking layer, since only the corresponding areas of the tool half are provided with this transferable or transferable masking layer.

1. (a) 50 bis 98,8 Gew.-% eines strahlenhärtbaren Acrylat-Oligomers;
2. (b) 1 bis 20 Gew.-% eines Radikalphotoinitiators oder einer Kombination aus wenigstens zwei unterschiedlichen Radikalphotoinitiatoren;
3. (c) 0,1 bis 48,9 Gew.-% eines Monomeren und/oder Oligomeren, das unterschiedlich zu dem Oligomer von (a) ist, ausgewählt aus strahlenhärtbaren Acryl-, Methacryl- und / oder Vinylderivaten und deren Mischungen;
4. (d) 0,1 bis 10 Gew.-% wenigstens eines Additivs, ausgewählt aus einem fluorhaltigen Tenside und / oder einer Mischung aus einem modifizierten Alkoxylat;
5. (e) und zum Rest sonstige Zusatzstoffe und/oder Verunreinigungen;

wobei die Summe der Gewichtsanteile der Komponenten (a), (b), (c), (d) und (e) zusammen 100 Gew.-% ergibt.The material of the masking layer can include the following components:

1. (a) 50 to 98.8% by weight of a radiation curable acrylate oligomer;
2. (b) 1 to 20% by weight of a free radical photoinitiator or a combination of at least two different free radical photoinitiators;
3. (c) 0.1 to 48.9% by weight of a monomer and/or oligomer different from the oligomer of (a) selected from radiation-curable acrylic, methacrylic and/or vinyl derivatives and mixtures thereof;
4. (d) 0.1 to 10% by weight of at least one additive selected from a fluorine-containing surfactant and/or a mixture of a modified alkoxylate;
5. (e) and the remainder other additives and/or impurities;

where the sum of the parts by weight of components (a), (b), (c), (d) and (e) together amounts to 100% by weight.

Radiation curing can take place in particular by UV radiation. In addition to the stated material based on radiation-curable material, the material of the masking layer can also be based on a polymeric hot-melt adhesive. The types of adhesive from Buehnen are particularly preferred, particularly the products U-333, U-3631 and C41404 (each as of the status of the application). The types of adhesive from 3M (as of the status of the application) are more preferred, particularly the product 3M Hot Melt Adhesive 3731-B, or the types of adhesive SIKAMELT-050 (as of the status of the application) from SIKA Automotive GmbH, Hamburg, and JOWAT 239.75, 264.00 and 239.70 or Jowatherm EP 16299.60 (in each case as of the status of the application) from JOWAT SE, Detmold.

The masking layer can preferably be applied using a doctor blade nozzle or spray nozzle. Alternatively or in combination, the masking layer can be sprayed on, brushed on, squeegeed on or poured on.

At least one additional separating layer can be provided between the masking layer and the tool half. This separating layer can form the surface of the tool half at least in that area or in those areas which form or form the later section or sections of the plastic part which is or are to have the masking layer. The release layer may facilitate the masking layer having greater adhesion to the formed plastic part than to the surface of the mold half. The separating layer itself can have a multilayer structure.
In one variant, the separating layer can be permanently connected to the tool half. In this way, in particular, a more uniform and more defined surface can be generated.
In a further step, the plastic part can be provided with a layer of paint or with several layers of paint. Subsequently, the masking layer and any parts of the paint layer or paint layers located on the masking layer can be removed from the plastic part.
The plastic part can be a trim part of a motor vehicle. The cladding part can be a bumper cladding or a sill cladding or a fender cladding or a door cladding or a roof cladding or a spoiler cladding.
Part of the invention is also a plastic part produced by the method described above or produced according to any one of claims 1 to 9.

character list

• 1 eine dreidimensionale Ansicht eines Kunststoffteils;
• 2 bis 9 den Ablauf eines erfindungsgemäßen Verfahrens anhand von Querschnitten durch ein Spritzgusswerkzeug;
• 10 bis 11 den Ablauf einer weiteren Variante eines erfindungsgemäßen Verfahrens anhand von Querschnitten durch ein Spritzgusswerkzeug;
• 12 bis 14 Lackierschritte als Ergänzung der in 2 bis 11 beschriebenen Verfahren.

The invention is explained below with reference to drawings that merely show exemplary embodiments. They show schematically:

• 1 a three-dimensional view of a plastic part;
• 2 until 9 the sequence of a method according to the invention based on cross sections through an injection molding tool;
• 10 until 11 the sequence of a further variant of a method according to the invention based on cross sections through an injection molding tool;
• 12 until 14 Painting steps as a supplement to the in 2 until 11 described procedure.

Elements that are the same or have the same function are provided with the same reference symbols in the figures.

the 1 shows a three-dimensional view of a plastic part 1, the plastic part 1 being a trim part of a motor vehicle, namely a bumper trim. A masking layer M is applied to two sections 7 of the plastic part 1 . The sections 7 of the plastic part 1 should not be provided with a layer of lacquer P and should remain free of lacquer for later use. These sections 7 must retain transparency for, for example, radar radiation, a lidar sensor or a camera arranged behind the bumper cover (correspondingly, the material of the plastic used for the plastic part is transparent or partially transparent depending on the electromagnetic radiation used or received), so that no paint may be applied here .

• Verfahren zum in-situ Aufbringen einer Maskierungsschicht M auf ein spritzgegossenes Kunststoffteil 1, umfassend die folgenden Schritte:
  • - Bereitstellen eines Spritzgusswerkzeuges 2 zur Herstellung des Kunststoffteils 1, wobei das Spritzgusswerkzeug 2 wenigstens zwei Werkzeughälften 3, 4 aufweist (vgl. 2), die zwischen sich eine Kavität 5 ausbilden, wobei diese Kavität 5 und die Ausformungen der Werkzeughälften 3, 4 die Gestalt des auszubildenden Kunststoffteils 1 vorgeben (vgl. 3);
  • - Aufbringen einer Maskierungsschicht M auf wenigstens eine der Werkzeughälften 3, wobei das Aufbringen auf demjenigen Bereich 6 oder auf denjenigen Bereichen 6 der Werkzeughälfte 3 erfolgt, welcher den späteren Abschnitt 7 oder welche die späteren Abschnitte 7 des Kunststoffteils 1 ausbildet oder ausbilden, der oder die die Maskierungsschicht M aufweisen soll oder sollen (vgl. 4 und 5);
  • - Schließen der Werkzeughälften 3, 4 (vgl. 6) und Einspritzen oder Eingießen eines fließfähigen, das Kunststoffteil 1 bildenden, Kunststoffes P in die Kavität 5 des Spritzgusswerkzeuges 2 (vgl. 7);
  • - Verfestigen oder Erstarren lassen des Kunststoffs P, um das Kunststoffteil 1 auszubilden (vgl. 8);
  • - Übertragen der Maskierungsschicht M auf den Abschnitt 7 oder auf die Abschnitte 7 des gebildeten Kunststoffteils 1, indem das Material und/oder der Aufbau der Maskierungsschicht M so gewählt ist, dass die Maskierungsschicht M eine größere Anhaftung zu dem gebildeten Kunststoffteil 1 aufweist als zu der Oberfläche der Werkzeughälfte 3, sodass bei der Entnahme des Kunststoffteils 1 aus dem Spritzgusswerkzeug 2 die Maskierungsschicht M ganz oder teilweise von der Werkzeughälfte 3 auf den oder die zur Maskierung vorgesehenen Abschnitt 7 oder Abschnitte 7 des Kunststoffteils 1 übertragen wird (vgl. 9).

The masking layer M was applied by the method described below:

• Method for applying a masking layer M in situ to an injection molded plastic part 1, comprising the following steps:
  • - Provision of an injection mold 2 for the production of the plastic part 1, the injection mold 2 having at least two mold halves 3, 4 (cf. 2 ), which form a cavity 5 between them, with this cavity 5 and the formations of the mold halves 3, 4 specifying the shape of the plastic part 1 to be formed (cf. 3 );
  • - Application of a masking layer M to at least one of the mold halves 3, with the application being made on that area 6 or on those areas 6 of the mold half 3 which forms or form the subsequent section 7 or sections 7 of the plastic part 1, the or those the masking layer M should or should have (cf. 4 and 5 );
  • - Closing the mold halves 3, 4 (cf. 6 ) and injecting or pouring a flowable plastic P forming the plastic part 1 into the cavity 5 of the injection molding tool 2 (cf. 7 );
  • - allowing the plastic P to solidify or solidify in order to form the plastic part 1 (cf. 8th );
  • - Transferring the masking layer M to the section 7 or sections 7 of the formed plastic part 1 by selecting the material and/or the structure of the masking layer M in such a way that the masking layer M has greater adhesion to the formed plastic part 1 than to the Surface of the tool half 3, so that when the plastic part 1 is removed from the injection molding tool 2, the masking layer M is wholly or partially transferred from the tool half 3 to the section or sections 7 or sections 7 of the plastic part 1 provided for masking (cf. 9 ).

1. (a) 50 bis 98,8 Gew.-% eines strahlenhärtbaren Acrylat-Oligomers;
2. (b) 1 bis 20 Gew.-% eines Radikalphotoinitiators oder einer Kombination aus wenigstens zwei unterschiedlichen Radikalphotoinitiatoren;
3. (c) 0,1 bis 48,9 Gew.-% eines Monomeren und/oder Oligomeren, das unterschiedlich zu dem Oligomer von (a) ist, ausgewählt aus strahlenhärtbaren Acryl-, Methacryl- und / oder Vinylderivaten und deren Mischungen;
4. (d) 0,1 bis 10 Gew.-% wenigstens eines Additivs, ausgewählt aus einem fluorhaltigen Tenside und / oder einer Mischung aus einem modifizierten Alkoxylat;
5. (e) und zum Rest sonstige Zusatzstoffe und/oder Verunreinigungen;

wobei die Summe der Gewichtsanteile der Komponenten (a), (b), (c), (d) und (e) zusammen 100 Gew.-% ergibt.The material of the masking layer M includes the following components:

1. (a) 50 to 98.8% by weight of a radiation curable acrylate oligomer;
2. (b) 1 to 20% by weight of a free radical photoinitiator or a combination of at least two different free radical photoinitiators;
3. (c) 0.1 to 48.9% by weight of a monomer and/or oligomer different from the oligomer of (a) selected from radiation-curable acrylic, methacrylic and/or vinyl derivatives and mixtures thereof;
4. (d) 0.1 to 10% by weight of at least one additive selected from a fluorine-containing surfactant and/or a mixture of a modified alkoxylate;
5. (e) and the remainder other additives and/or impurities;

where the sum of the parts by weight of components (a), (b), (c), (d) and (e) together amounts to 100% by weight.

In the 10 and 11 is shown in a variant that at least one additional separating layer S is provided between the masking layer M and the tool half 3, which forms the surface of the tool half 3 at least in that area 6 or in those areas 6. This parting line S can be permanently connected to the tool half 3 .

In the 12 and 13 is shown as a supplement to the method described above, that the plastic part 1 is provided with a layer of paint P or with several layers of paint P in a further step. In 12 the painting step is not yet complete and the masking layer M on one of the sections 7 is still partially recognizable. In 13 If the plastic part 1 is then completely provided with a paint layer P or with several paint layers P on the visible outer surface.

In the 14 it can be seen that the masking layer M and any parts of the paint layer P or paint layers P that may be located on the masking layer M are then removed from the plastic part 1 . As required, sections 7 are then free of paint.

QUOTES INCLUDED IN DESCRIPTION

This list of the documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• EP 1629960 [0007]

Claims (10)

Method for applying a masking layer (M) in situ to an injection molded plastic part (1), comprising the following steps: - Providing an injection molding tool (2) for producing the plastic part (1), the injection molding tool (2) having at least two tool halves (3, 4) which form a cavity (5) between them, this cavity (5) and the formations the tool halves (3, 4) specify the shape of the plastic part (1) to be formed; - Application of a masking layer (M) to at least one of the tool halves (3), the application being carried out on that area (6) or on those areas (6) of the tool half (3) which the later section (7) or which the later forming or forming sections (7) of the plastic part (1) which is or are to have the masking layer (M); - Closing the tool halves (3, 4) and injecting or pouring a free-flowing plastic (P) forming the plastic part (1) into the cavity (5) of the injection molding tool (2); - allowing the plastic (P) to solidify or solidify in order to form the plastic part (1); - Transfer of the masking layer (M) to the section (7) or to the sections (7) of the plastic part (1) formed, by the material and/or the structure of the masking layer (M) being selected such that the masking layer (M) has greater adhesion to the plastic part (1) formed than to the surface of the tool half (3), so that when the plastic part (1) is removed from the injection molding tool (2), the masking layer (M) is completely or partially peeled off the tool half (3) is transferred to the section or sections (7) or sections (7) of the plastic part (1) provided for masking. procedure after claim 1 , characterized in that the material of the masking layer (M) comprises the following components: (a) 50 to 98.8% by weight of a radiation-curable acrylate oligomer; (b) 1 to 20% by weight of a free radical photoinitiator or a combination of at least two different free radical photoinitiators; (c) 0.1 to 48.9% by weight of a monomer and/or oligomer different from the oligomer of (a) selected from radiation-curable acrylic, methacrylic and/or vinyl derivatives and mixtures thereof; (d) 0.1 to 10% by weight of at least one additive selected from a fluorine-containing surfactant and/or a mixture of a modified alkoxylate; (e) and the remainder other additives and/or impurities; where the sum of the parts by weight of components (a), (b), (c), (d) and (e) together amounts to 100% by weight. Method according to one of the preceding claims, characterized in that the masking layer increases its strength or hardness as a result of the heat that is present or that is released from the flowable plastic. Method according to one of the preceding claims, characterized in that at least one additional separating layer (S) is provided between the masking layer (M) and the tool half (3) which at least in that area (6) or in those areas (6) the surface of the tool half (3). procedure after claim 4 , characterized in that the parting line (S) is permanently connected to the tool half (3). Method according to one of the preceding claims, characterized in that the plastic part (1) is provided with a layer of lacquer (P) or with several layers of lacquer (P) in a further step. procedure after claim 6 , characterized in that subsequently the masking layer (M) and any parts of the paint layer (P) or paint layers (P) located on the masking layer (M) are removed from the plastic part (1). Method according to one of the preceding claims, characterized in that the plastic part is a lining part of a motor vehicle. procedure after claim 8 , characterized in that the paneling part is a bumper panel or a rocker panel or a fender panel or a door panel or a roof panel or a spoiler panel. Plastic part produced by a method according to one of the preceding claims.

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