High-strength thermosetting type display screen sealing foam rubber

Abstract

A high-strength thermosetting type display screen sealing foam adhesive relates to the technical field of display equipment manufacturing, and comprises a PET base material layer, one side of the PET base material layer is coated with a release film layer through a first adhesive layer, the other side of the PET base material layer is provided with a second adhesive layer, and the other side of the PET base material layer is coated with a foaming layer in a hot-press fitting mode. A TPU layer is formed on one side of the foaming layer through coating or tape casting, and a third adhesive layer is coated on the surface of the TPU layer. According to the utility model, the shearing resistance and the aging resistance of the foam rubber are obviously improved, and the problems that the traditional PU foam is low in layering force and the rubber layer is easy to lose efficacy are solved. Under the synergistic effect of the TPU layer and the foaming layer, no-residue stripping can be realized when the adhesive tape is removed, and the limitation that traditional reworking depends on solvent cleaning is broken through.

Description

Technical Field

[0001] This utility model relates to the field of display device manufacturing technology, and in particular to a high-strength thermosetting display screen sealing foam adhesive. Background Technology

[0002] In the display device manufacturing industry, foam double-sided tape serves as a crucial fixing material between the screen module and the frame, requiring it to simultaneously meet requirements such as high adhesive strength, vibration and shock resistance, aging resistance, and reworkability. Traditional display screen sealing tape typically uses polyurethane (PU) foam as a buffer layer, with a density ranging from 200-400 kg / m³, bonded to the substrate by coating both sides with acrylic adhesive layers. However, this structure has the following limitations:

[0003] On the one hand, the delamination force of PU foam is usually ≤10 N / 25mm, and its shear strength is low. Under long-term load or extreme temperature / humidity environment, it is prone to delamination or creep, leading to screen fixation failure. In addition, its compression deformation recovery ability (25% compression permanent deformation) is poor, making it difficult to maintain stable sealing performance after equipment assembly.

[0004] On the other hand, traditional acrylic adhesives have a peel strength of approximately 15 N / 25 mm, which can easily lead to interface peeling when bonding low surface energy materials such as aluminum plates and PCs. This is especially true after high and low temperature cycling, which reduces the cohesive force of the adhesive layer, increasing the risk of screen detachment. Other similar products do not perform well on uneven casings or corrugated panels and require a primer to improve adhesion.

[0005] Furthermore, when removing the tape, the traditional foam layer is prone to breakage and residue, requiring solvent cleaning or mechanical scraping, which can easily damage the screen surface. In addition, the interface between the adhesive layer and the foam lacks a controllable separation design, making it difficult to achieve quick rework without residue. Utility Model Content

[0006] The purpose of this invention is to provide a high-strength thermosetting display screen sealing foam adhesive, which has both high-strength bonding and reversible operation characteristics, in order to meet the screen sealing requirements of high-reliability display devices.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a high-strength thermosetting display screen sealing foam adhesive, comprising a PET substrate layer, wherein the PET substrate layer is a PET substrate that has undergone plasma treatment on both sides, and the two sides of the PET substrate layer are respectively coated with a first adhesive layer and a second adhesive layer after being treated with polyurethane primer. Both the first adhesive layer and the second adhesive layer are thermosetting hot melt adhesives. A release film layer is attached to one side of the first adhesive layer, and a foam layer is attached to one side of the second adhesive layer by hot pressing. The foam layer is PE foam that has undergone plasma treatment on both sides, and a TPU layer is formed on the other side of the foam layer by coating or casting. A third adhesive layer is coated on the surface of the TPU layer, and the third adhesive layer is acrylic adhesive.

[0008] Preferably, the foam layer is high-strength PE foam with a density of 50-300 kg / m³.

[0009] More preferably, the elastic modulus of the TPU layer is ≥20 MPa and the elongation is ≥500%, and the color of the TPU layer 2 is black.

[0010] More preferably, the thickness of the TPU layer is 5-50 μm.

[0011] More preferably, the hot melt adhesive is a thermosetting hot melt adhesive, and the present invention preferably uses a thermosetting irreversible hot melt adhesive.

[0012] More preferably, the first adhesive layer and the second adhesive layer are both hot melt adhesives with a thickness of 40-80 μm; the third adhesive layer is acrylic adhesive with a thickness of 50-100 μm and a peel strength ≥20 N / 25 mm.

[0013] More preferably, the PET substrate layer is selected as black PET.

[0014] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0015] 1. The foam layer and PET substrate layer are bonded together by hot pressing. The interface is highly dense. Combined with the high elastic modulus and elongation of the TPU layer, the overall shear resistance and delamination resistance of the foam adhesive are significantly improved, achieving a high-strength bonding effect. This can effectively prevent interface separation problems caused by long-term load or vibration when fixing the screen.

[0016] 2. The third adhesive layer uses hot melt adhesive or high peel strength acrylic adhesive, combined with the surface reinforcement effect of the TPU layer on the foam layer, which greatly improves the adhesion of the tape to low surface energy materials such as PC, aluminum plate, corrugated plate and rough casing, and does not require primer treatment, ensuring stable adhesion performance even in extreme environments such as high temperature and high humidity.

[0017] 3. The high elasticity of the TPU layer and the controllability of the interface with the foam layer allow the residual adhesive layer to be pulled to the surface of the TPU layer by stretching and peeling when removing the tape. Combined with the rigid support of the PET substrate layer, this enables the complete peeling of the tape during screen rework, avoiding the problem of traditional foam adhesive breaking and leaving residue. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure in the embodiment.

[0019] In the picture:

[0020] 1. PET substrate layer; 2. First adhesive layer; 3. Release film layer; 4. Second adhesive layer; 5. Foam layer; 6. TPU layer; 7. Third adhesive layer. Detailed Implementation

[0021] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments and accompanying drawings. The content mentioned in the embodiments is not intended to limit the present invention.

[0022] like Figure 1 As shown, a high-strength thermosetting display screen sealing foam adhesive includes a PET substrate layer 1, which is a PET substrate that has been plasma-treated on both sides. After being treated with polyurethane primer, a first adhesive layer 2 and a second adhesive layer 4 are respectively coated on both sides of the PET substrate layer 1. Both the first adhesive layer 2 and the second adhesive layer 4 are thermosetting hot melt adhesives. A release film layer 3 is attached to one side of the first adhesive layer 2. A foam layer 5 is attached to one side of the second adhesive layer 4 by hot pressing. The foam layer 5 is PE foam that has been plasma-treated on both sides. A TPU layer 6 is formed on the other side of the foam layer 5 by coating or casting. A third adhesive layer 7 is coated on the surface of the TPU layer 6. The third adhesive layer 7 is acrylic adhesive.

[0023] In the above structure, the foam layer 5 is high-strength PE foam, which also has good compressibility and a density of 50-300 kg / m³. 3 At 25% CFD, the maximum stress per unit area of ​​the material is ≤30Kpa, and the foam delamination force is ≥20N / 25mm, which overcomes the limitations of traditional PU foam (density 200-400 kg / m³). 3 To address the shortcomings of low strength (delamination force ≤10N / 25mm), the load-bearing capacity, shear resistance, and resistance to extreme environmental aging tests of foam double-sided adhesive have been improved.

[0024] In addition, the TPU layer 6 has an elastic modulus ≥20 MPa and an elongation ≥500%, with a thickness of 5-50 μm. It has high strength and high elasticity, which allows the residual adhesive layer to be pulled to the surface of the TPU layer 6 by stretching and peeling when removing the tape. Combined with the rigid support of the PET substrate layer 1, the tape can be completely peeled off during screen rework, avoiding the problem of traditional foam adhesive breaking and leaving residue.

[0025] In this embodiment, both the first adhesive layer 2 and the second adhesive layer 4 are thermosetting hot melt adhesives with a thickness of 40-80 μm, a coating temperature of 50-80℃, and an activation temperature of 100-110℃. The peel force when bonded to PC and aluminum sheets is ≥40N / 25mm, which is higher than the 15N / 25mm peel force of traditional acrylic adhesives, and the bonding firmness is much higher than that of traditional acrylic adhesives. The third adhesive layer 7 is made of acrylic adhesive with a thickness of 50-100 μm and a peel force ≥20N / 25mm.

[0026] It should be noted that those skilled in the art should know that the foam adhesive has a release film on only one side, so it can be made into a roll product.

[0027] The production process of the high-strength thermosetting display screen sealing foam adhesive provided in the above embodiments is roughly as follows:

[0028] 1. Select a 50µm thick black PET substrate, treat both sides with plasma or corona treatment, then apply a polyurethane primer, followed by direct application of a 40-80µm thick hot melt adhesive. The hot melt adhesive is baked at 50-80℃. Plasma treatment mainly involves bombarding the surface with high-energy particles to increase the surface energy of the PET substrate and form a micron-level rough structure, thereby increasing the anchoring area of ​​the adhesive layer and improving the subsequent bonding strength between the adhesive layer and the substrate.

[0029] 2. Perform plasma treatment on both sides of the PE foam, then apply a primer, followed by surface TPU coating reinforcement, and then coat the surface with an acrylic adhesive layer with a thickness of 50-100um and a peel strength ≥20N / 25mm, or apply a hot melt adhesive layer.

[0030] 3. The other side of the PE foam is bonded to the black PET substrate by heating and hot pressing at a temperature of 50-80℃. The two are combined to form a high-strength thermosetting display screen sealing foam adhesive. The black PET substrate enables the foam adhesive to have light-blocking properties, preventing light leakage after it is applied to the display screen.

[0031] 4. When applying the adhesive, the foam side with acrylic adhesive is first attached to the cover glass, and the hot melt adhesive side is attached to the shell. The hot melt adhesive is activated and fully bonded to the shell by heating and pressurizing at 100-110℃.

[0032] Those skilled in the art should know that, depending on the actual application needs and requirements, the adhesive layer can be one or a combination of acrylic adhesive or hot melt adhesive, and the PE foam layer can also be replaced with high-strength soft foams such as PU polyurethane, acrylic, or PP foam. TPU can also be used as a base coat to improve adhesion.

[0033] This invention employs a multi-layer composite structure design, using a PET substrate layer as the core carrier. A high-strength PE foam layer is hot-pressed onto the PET substrate, while a high-elasticity TPU layer and a high-adhesion adhesive layer are coated / cast onto the surface of the foam layer. The core of this design lies in utilizing the high tensile strength (≥20 MPa) and elongation (≥500%) of the TPU layer to reinforce the surface of the foam layer. Combined with low-density (50-300 kg / m³) and high delamination force (≥20 N / 25mm) PE foam, and a synergistic bonding system of hot melt adhesive and acrylic adhesive, a composite structure is formed that combines rigid support, flexible cushioning, and controllable interface separation. Furthermore, high-strength interlayer bonding is achieved through plasma treatment, primer coating, and hot-pressing processes.

[0034] This structure significantly improves the shear resistance and aging resistance of the foam adhesive, with a 25% compression set ≤30kPa and a peel force of ≥40 N / 25mm against PC / aluminum sheets. It solves the problems of low delamination force (≤10 N / 25mm) and easy adhesive layer failure in traditional PU foam. The synergistic effect of the TPU layer and the foam layer allows for residue-free removal of the tape, overcoming the limitations of traditional rework relying on solvent cleaning. The production process simplifies the workflow through substrate pretreatment and hot-pressing lamination, making it compatible with various foaming materials (such as PU, PP, TPU, TPE, acrylic foam, etc.) and combinations of acrylic adhesive on one side and hot melt adhesive on the other, or both sides being thermoplastic adhesive layers. This ensures high reliability while reducing manufacturing costs, meeting the requirements for thinner and lighter displays and high environmental tolerance.

[0035] In practical applications, foam acrylic adhesive is used to bond the glass panel to achieve foam positioning, and pressure holding and heating are used to activate and bond the product to the rough casing. This solves the pain points of the original similar products, such as the need for casing base coating treatment, and significantly improves the bonding effect and bonding efficiency.

[0036] To facilitate understanding by those skilled in the art of the improvements of this utility model compared to the prior art, some of the accompanying drawings and descriptions of this utility model have been simplified. The above embodiments are preferred implementations of this utility model. In addition, this utility model can be implemented in other ways. Any obvious substitutions without departing from the concept of this technical solution are within the protection scope of this utility model.

Claims

1. A high-strength thermoset display screen sealing foam glue, comprising a PET substrate layer (1), characterized in that: The PET substrate layer (1) is a PET substrate that has been plasma treated on both sides. The two sides of the PET substrate layer (1) are coated with a first adhesive layer (2) and a second adhesive layer (4). The first adhesive layer (2) and the second adhesive layer (4) are both thermosetting hot melt adhesives. A release film layer (3) is attached to one side of the first adhesive layer (2). A foam layer (5) is attached to one side of the second adhesive layer (4) by hot pressing. The foam layer (5) is PE foam that has been plasma treated on both sides. A TPU layer (6) is formed on the other side of the foam layer (5) by coating or casting. A third adhesive layer (7) is coated on the surface of the TPU layer (6). The third adhesive layer (7) is acrylic adhesive.

2. The high-strength thermosetting display screen sealing foam adhesive according to claim 1, characterized in that: The foam layer (5) is a high-strength PE foam with a density of 50-300 kg / m³.

3. The high-strength thermosetting display screen sealing foam adhesive according to claim 1, characterized in that: The TPU layer (6) has an elastic modulus ≥20 MPa and an elongation ≥500%, and the TPU layer (6) is black.

4. The high-strength, thermoset display enclosure bubble wrap of claim 2, wherein: The thickness of the TPU layer (6) is 5-50 μm.

5. The high-strength, thermoset display enclosure bubble wrap of claim 1, wherein: The hot melt adhesive is a thermosetting, irreversible hot melt adhesive.

6. The high-strength, thermoset display enclosure bubble wrap of claim 5, wherein: The first adhesive layer (2) and the second adhesive layer (4) are both hot melt adhesives with a thickness of 40-80 μm; the third adhesive layer (7) is acrylic adhesive with a thickness of 50-100 μm and a peel force ≥20 N / 25 mm.

7. The high-strength, thermoset display enclosure bubble wrap of any of claims 1-6, wherein: The PET substrate layer (1) is selected as black PET.

Images