阅读说明：本技术 一种返工双面泡棉胶带、返工方法和制备方法 (Reworking double-sided foam adhesive tape, reworking method and preparation method ) 是由 周永南 王文鹏 于 2021-05-17 设计创作，主要内容包括：本发明公开了一种返工双面泡棉胶带,包括：弹性体拉伸层,具有厚度方向相对的第一表面和第二表面；两层泡棉层,分别固定设置于弹性体拉伸层的第一表面和第二表面；两层增强膜层,分别固定设置于泡棉层背向弹性体拉伸层的表面；两层压敏胶层,分别固定设置于增强膜层背向泡棉层的表面。弹性体拉伸层的断裂伸长率和拉伸强度均优于泡棉层,弹性体拉伸层变形会破坏泡棉层,进而与泡棉层相分离。本发明还公开了一种基于返工双面泡棉胶带的返工方法和制备方法。(The invention discloses a reworking double-sided foam adhesive tape, which comprises: an elastomeric tensile layer having first and second surfaces opposite in thickness direction; the two foam layers are fixedly arranged on the first surface and the second surface of the elastic body stretching layer respectively; the two reinforced film layers are respectively fixedly arranged on the surfaces of the foam layers, back to the elastic body stretching layer; and the two pressure-sensitive adhesive layers are respectively fixedly arranged on the surface of the reinforced film layer, which is back to the foam layer. The elongation at break and the tensile strength of the elastic body stretching layer are superior to those of the foam layer, and the deformation of the elastic body stretching layer can damage the foam layer and further separate from the foam layer. The invention also discloses a reworking method and a preparation method based on the reworked double-sided foam adhesive tape.)

1. A reworked double-sided foam adhesive tape is characterized by comprising:

an elastomeric tensile layer having first and second surfaces opposite in thickness direction;

the two foam layers are fixedly arranged on the first surface and the second surface of the elastic body stretching layer respectively;

the two reinforced film layers are respectively fixedly arranged on the surfaces of the foam layers, back to the elastic body stretching layer;

and the two pressure-sensitive adhesive layers are respectively fixedly arranged on the surface of the reinforced film layer back to the foam layer.

2. The reworked double-sided foam tape according to claim 1, wherein the stretched elastomer layer is made of at least one of a polyurethane elastomer and a rubber elastomer.

3. A reworking method for reworking a double-sided foam adhesive tape is characterized by comprising the following steps:

s1: breaking two foam layers from the thickness direction section of the edge of the reworked double-sided foam adhesive tape until the elastomer stretching layer at the edge of the reworked double-sided foam adhesive tape is separated from the two foam layers;

s2, stretching the elastomer stretching layer separated from the foam layer obtained in the S1 until the elastomer stretching layer is completely separated from the foam layer;

s3: and stripping the laminated body containing the pressure-sensitive adhesive layer, the reinforcing film layer and the residual foam layer from the surface of the workpiece.

4. The method of reworking a double-sided foam tape according to claim 3, wherein the stretching direction in the step S2 is parallel to the bonding surface of the reworked double-sided foam tape.

5. A method of reworking a double-sided foam tape according to claim 3, further comprising in S2: and inserting a hard sheet between the separated elastomer stretching layer and the foam layer, and driving the sheet to press the elastomer stretching layer along the thickness direction of the reworked double-sided foam adhesive tape.

6. A preparation method of a reworked double-sided foam adhesive tape is characterized by comprising the following steps:

s1: preparing an elastomer stretching layer, applying a foaming raw material on the surface of the elastomer stretching layer, and foaming to obtain a foam core material with a double-sided foam layer;

s2: applying a first adhesive to two surfaces of the foam core material obtained in the step S1, which are opposite to each other in the thickness direction, and then respectively attaching the reinforcing film layers;

s3: and (4) respectively applying a second adhesive on the surfaces of the two reinforced film layers of the laminated structure obtained in the step (S2) to prepare the reworked double-sided foam adhesive tape with the surface pressure-sensitive adhesive layer.

7. The method for preparing rework double-sided foam adhesive tape according to claim 6, wherein the foam layer is made of at least one material selected from polyurethane foam, polyethylene foam and ethylene-vinyl acetate copolymer foam, and the first adhesive is one of acrylic adhesive, rubber adhesive and polyurethane adhesive.

8. The method for preparing rework double-sided foam tape of claim 6, wherein the foam layer is polyurethane foam; the foaming raw materials of the foam layer mainly comprise polyisocyanate, polyol, a catalyst, a foaming agent, a foam stabilizer and color paste; the molar ratio of the polyisocyanate to the polyol is 1-1.2: 1;

according to the weight percentage, the catalyst accounts for 0.1-0.5% of the foaming raw material, the foaming agent accounts for 3-5% of the foaming raw material, the foam stabilizer accounts for 0.5-2% of the foaming raw material, and the color paste accounts for 0.8-4% of the foaming raw material.

9. The method for preparing a reworked double-sided foam adhesive tape according to claim 6, wherein the polyurethane foam is subjected to 180-240 kg/m high-speed harvest, and the 25% compression resilience force is not less than 0.20 MPa; the tensile strength of the elastomer tensile layer is not less than 40Mpa and the elongation at break is not less than 450%.

Technical Field

The invention relates to the technical field of electronic equipment adhesive tapes, in particular to a reworking double-sided foam adhesive tape, a reworking method and a preparation method.

Background

The double-sided foam adhesive tape is an adhesive tape with a foam layer as a base material and two opposite surfaces in the thickness direction coated with pressure-sensitive adhesive, is mainly used for fixing a back shell, a screen frame body, a battery and the like of an electronic product and has good buffering performance. The problem such as inaccurate or attached work piece damage of counterpoint can appear unavoidably in the in-service use in-process of two-sided bubble cotton sticky tape, needs to remove the work piece surface of two-sided sticky tape from both sides, and the processing of doing over again promptly, traditional bubble cotton sticky tape can't satisfy the requirement of doing over again.

As shown in the attached drawing 1, the improved technical scheme is that a reinforced film layer, such as a TPU layer 3 and a PET layer 4 in the drawing, is fixed on the surface of a foam layer 2, and a pressure-sensitive adhesive layer 5 attached to a workpiece is coated on the surface of the reinforced film layer. The rework operation includes: the foam layer was divided into two from the thickness direction cross section of the tape with a blade, and then the laminate of the pressure-sensitive adhesive layer, the reinforcing film layer and the residual foam was removed. The reinforced film layer is used as a base material layer of the foam layer and the pressure-sensitive adhesive layer, and residues of the pressure-sensitive adhesive on the surface of the workpiece are reduced.

The defects of the rework operation in the prior art scheme are as follows: the thickness of the foam layer is small, and the reinforcing film layer is inevitably damaged in the process of dividing the foam into two parts by the blade; secondly, the foam adhesive tape is adhered between the two hard workpieces, the operation action of cutting the foam by the blade is limited, the workload is large, and the consumed time is long. In addition, the workpieces bonded by the double-sided adhesive tape are in a scarf joint structure, and the blade cannot extend between the two workpieces, so that the application range of the existing reworked double-sided foam adhesive tape sold in the market is further narrowed.

Disclosure of Invention

One of the purposes of the invention is to overcome the defects in the prior art and provide a reworked double-sided foam adhesive tape, which separates an elastomer stretching layer from a foam layer by utilizing the characteristic of forced drafting deformation of the elastomer stretching layer and reduces the workload of cutting the foam by a blade in reworking operation.

In order to achieve the technical effects, the technical scheme of the invention is as follows: a rework double-sided foam tape, comprising:

an elastomeric tensile layer having first and second surfaces opposite in thickness direction;

the two foam layers are fixedly arranged on the first surface and the second surface of the elastic body stretching layer respectively;

the two reinforced film layers are respectively fixedly arranged on the surfaces of the foam layers, back to the elastic body stretching layer;

and the two pressure-sensitive adhesive layers are respectively fixedly arranged on the surface of the reinforced film layer back to the foam layer.

Specifically, a release layer is attached to the surface of at least one pressure-sensitive adhesive layer to protect the pressure-sensitive adhesive layer; the two reinforcing film layers are made of the same or different materials, the selectable materials comprise polyethylene terephthalate (PET) and polyurethane elastomer rubber (TPU), and further, one reinforcing film layer is made of the PET material, and the other reinforcing film layer is made of the TPU material; furthermore, a PET (polyethylene terephthalate) reinforced film layer is fixedly arranged on the first surface opposite to the thickness direction of the pressure-sensitive adhesive layer, and a release layer is attached to the second surface; furthermore, release layer is two-sided release layer, and the two-sided cotton sticky tape of bubble of being convenient for realizes the rolling through one from the type layer.

The fixed connection between the foam layer and the elastomer stretching layer comprises adhesive bonding or fixed connection through surface foaming, and specifically comprises a double-sided foam layer prepared by foaming on the surface of the elastomer stretching layer or a foam layer prepared by foaming on the surface of the reinforced film layer.

The preferable technical scheme is that the foam layer is made of at least one selected from polyurethane foam, polyethylene foam and ethylene-vinyl acetate copolymer foam, and the first adhesive is one selected from acrylic acid adhesive and rubber adhesive.

The second purpose of the invention is to provide a reworking method for reworking a double-sided foam adhesive tape, which comprises the following steps:

s1: breaking two foam layers from the thickness direction section of the edge of the reworked double-sided foam adhesive tape until the elastomer stretching layer at the edge of the reworked double-sided foam adhesive tape is separated from the two foam layers;

s2, stretching the elastomer stretching layer separated from the foam layer obtained in the S1 until the elastomer stretching layer is completely separated from the foam layer;

s3: and stripping the laminated body containing the pressure-sensitive adhesive layer, the reinforcing film layer and the residual foam layer from the surface of the workpiece.

Specifically, the thickness direction cross section includes but is not limited to a cross section perpendicular to the tiled reworked double-sided foam adhesive tape, and the thickness direction cross section may further have an acute angle and an obtuse angle included angle with the tiled reworked double-sided foam adhesive tape. Preferably, the cross section in the thickness direction is perpendicular to the reworked double-sided foam adhesive tape in a flat-laid state.

The preferable technical scheme is that the stretching direction in the S2 process is parallel to the bonding surface of the reworked double-sided foam adhesive tape.

Preferably, S2 further includes: and inserting a hard sheet between the separated elastomer stretching layer and the foam layer, and driving the sheet to press the elastomer stretching layer along the thickness direction of the reworked double-sided foam adhesive tape. The sheet has certain rigidity and toughness, the hard sheet is inserted between the separated elastic body stretching layer and the foam layer positioned on the first surface of the elastic body stretching layer, the sheet presses the elastic body stretching layer, the foam layer on the second surface of the elastic body stretching layer is compressed, the distance between the elastic body stretching layer and the foam layer on the first surface is enlarged, namely, the peeling force is applied to the elastic body stretching layer and the foam layer on the first surface of the elastic body stretching layer, and the reworking efficiency of the reworking double-sided foam adhesive tape is further improved. Furthermore, the extending end of the sheet is smooth, so that the elastic body stretching layer is prevented from being damaged.

The invention also aims to provide a preparation method of the reworked double-sided foam adhesive tape, which comprises the following steps:

s1: preparing an elastomer stretching layer, applying a foaming raw material on the surface of the elastomer stretching layer, and foaming to obtain a foam core material with a double-sided foam layer;

s2: applying a first adhesive to two surfaces of the foam core material obtained in the step S1, which are opposite to each other in the thickness direction, and then respectively attaching the reinforcing film layers;

s3: and (4) respectively applying a second adhesive on the surfaces of the two reinforced film layers of the laminated structure obtained in the step (S2) to prepare the reworked double-sided foam adhesive tape with the surface pressure-sensitive adhesive layer.

The material of the foam layer is at least one selected from polyurethane foam, polyethylene foam and ethylene-vinyl acetate copolymer foam, and the first adhesive is one of acrylic acid adhesive, rubber adhesive and polyurethane adhesive. The foam layer is a single-layer foam or a composite laminated structure of multiple layers of foam. Further, the foam layer is polyurethane single-layer foam, polyethylene single-layer foam and ethylene-vinyl acetate copolymer single-layer foam, and the single-layer foam is formed in a one-step foaming mode.

The preferable technical scheme is that the foam layer is polyurethane foam; the foaming raw materials of the foam layer mainly comprise polyisocyanate, polyol, a catalyst, a foaming agent, a foam stabilizer and color paste; the molar ratio of the polyisocyanate to the polyol is 1-1.2: 1;

according to the weight percentage, the catalyst accounts for 0.1-0.5% of the foaming raw material, the foaming agent accounts for 3-5% of the foaming raw material, the foam stabilizer accounts for 0.5-2% of the foaming raw material, and the color paste accounts for 0.8-4% of the foaming raw material.

The preferable technical scheme is that the density of the polyurethane foam is 180-240 kg/m³25% compression resilience force is not less than 0.20 Mpa; the tensile strength of the elastomer tensile layer is not less than 40Mpa and the elongation at break is not less than 450%.

The invention has the advantages and beneficial effects that:

the laminated structure of the foam layer, the elastomer stretching layer and the foam layer is adopted to replace single-layer foam in the prior art, the breaking elongation and the tensile strength of the elastomer stretching layer are superior to those of the foam layer, the foam layer can be damaged by the deformation of the elastomer stretching layer and then separated from the foam layer, the workload of manually cutting the foam layer in the rework operation is reduced, and the rework is quicker and more convenient;

the foam cotton layer, the elastomer stretching layer and the laminated structure of the foam cotton layer are prepared on the surface of the elastomer stretching layer in a foaming manner, so that the use of an adhesive between the foam cotton layer and the elastomer stretching layer can be reduced, the production efficiency is improved, the foam cotton layer and the elastomer stretching layer are combined more firmly, the cohesive strength is improved, and the risk of layering caused by stress is reduced; the total thickness of the product is easier to adjust, and the requirements of different use occasions can be met.

Drawings

FIG. 1 is a schematic structural diagram of a reworked double-sided foam tape in the prior art;

FIG. 2 is a schematic structural view of a reworked double-sided foam tape of an embodiment;

FIG. 3 is a schematic view of another embodiment of a reworked double-sided foam tape;

FIG. 4 is a diagram showing the usage status of the rework process of reworking double-sided foam tape;

FIG. 5 is a diagram showing the usage state of the rework process for reworking a sample of double-sided foam tape 2-2';

in the figure: 1. an elastomeric tensile layer; 2. soaking a cotton layer; 3. a TPU layer; 4. a PET layer; 5. a pressure sensitive adhesive layer; 6. a release layer; 7. a blade.

Detailed Description

The following further describes embodiments of the present invention with reference to examples. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.

The pressure-sensitive adhesive layer used for bonding the workpiece in the reworked double-sided foam adhesive tape is usually a pressure-sensitive adhesive, and can be selected from acrylate pressure-sensitive adhesive, rubber pressure-sensitive adhesive and polyurethane pressure-sensitive adhesive. The optional EVA, PE, XPE, PU, EPE etc. of soaking the cotton layer have elasticity, flexible sheet concurrently. The material and thickness of the foam determine the single-layer tensile resistance of the foam layer. The materials of the examples are shown in the following table:

as shown in fig. 2, in an embodiment, the laminated structure of the reworked double-sided foam tape sequentially comprises: pressure-sensitive adhesive layer 5, TPU layer 3, foam layer 2, elastomer stretch layer 1, foam layer 2, TPU layer 3 and pressure-sensitive adhesive layer 5. The two TPU layers 3 ensure that the reworked double-sided foam adhesive tape has good curved surface and cambered surface fitting degree. The elastomer stretching layer 1 is made of polyurethane elastomer.

The TPU layers 3 are all TPU-4, polyurethane adhesives in the upper surface are coated on the two surfaces of the foam layer 2 to be adhered with the TPU layers 3, and the elastomer stretching layer 1 respectively adopts TPU-1, TPU-2 and TPU-3 which are respectively and correspondingly marked as samples 1-1, 1-2 and 1-3.

In another embodiment, as shown in fig. 3, the laminated structure of the reworked double-sided foam tape sequentially comprises: the pressure-sensitive adhesive layer 5, the PET layer 4, the foam layer 2, the elastomer stretching layer 1, the foam layer 2, the TPU layer 3 and the pressure-sensitive adhesive layer 5, wherein the two foam layers 2 are prepared by applying foaming materials to the surface of the elastomer stretching layer 1 in sequence and foaming for two times, and the elastomer stretching layer 1 respectively adopts TPU-1, TPU-2 and TPU-3 and respectively corresponds to samples 2-1, 2-2 and 2-3.

A release layer 6 is arranged on the surface of a pressure-sensitive adhesive layer 5 in the reworked double-sided foam adhesive tape, and the double-sided foam adhesive tape is convenient to roll. Compared with the TPU material, the PET material texture is harder, the PET layer 4 of the double-sided foam adhesive tape reworked on the same layer is positioned on the inner side of the TPU layer 3 in the rolling state, and the elastic deformation of the TPU layer 3 meets the requirement of the double-sided foam adhesive tape reworked for rolling and packaging.

The preparation method of the reworked double-sided foam adhesive tape samples 2-1, 2-2 and 2-3 is as follows:

s1: mixing polyester polyol, a catalyst, a foam stabilizer, a foaming agent and color paste according to a predetermined amount, and then uniformly mixing the mixture with a predetermined amount of diphenylmethane diisocyanate to obtain a foaming raw material; taking an elastomer stretching layer as a base material, applying a foaming raw material on a first surface opposite to the thickness direction of the elastomer stretching layer, quickly passing through a coating die head with preset parameters, coating to form a coating with a preset thickness, and foaming; and applying a foaming raw material on a second surface opposite to the first surface in the thickness direction of the elastomer stretching layer, and foaming to obtain the foam core material with a foam layer/elastomer stretching layer/foam layer structure.

2-1, foam layer foaming process parameters: the polyisocyanate and the polyol are in a molar ratio of 1.1:1, and the foaming raw materials comprise, by weight, 0.35% of catalyst, 4% of foaming agent, 1.75% of foam stabilizer and 2.5% of color paste besides the polyisocyanate and the polyol; the foaming temperature is not higher than 90 ℃ at most, and the foaming time is 5 min; the thickness of the foamed foam layer was 350. mu.m. 2-2 and 2-3 of foam layer foaming process parameters: the polyisocyanate and the polyol are in a molar ratio of 1.12:1, and the foaming raw materials comprise, by weight, 0.3% of catalyst, 4.2% of foaming agent, 1.55% of foam stabilizer and 2.9% of color paste besides the polyisocyanate and the polyol; the foaming temperature is not higher than 90 ℃ at most, and the foaming time is 5.5 min; the density of the obtained foam is 200-210 kg/m²。

The process for preparing the reworked double-sided foam adhesive tape by using the 2-1, 2-2 and 2-3 foam core materials comprises the following steps:

1. coating a pressure-sensitive adhesive on the first surface of the reinforcing layer TPU, controlling the coating weight to be 35 mu m in thickness, drying, and then compounding with the foam core material to form a reinforcing layer TPU/foam core material composite structure;

2. coating a pressure-sensitive adhesive on the first surface of the enhancement layer PET, controlling the coating weight to be 35 μm thick, drying, and compounding with the other surface of the foam core material in the previous step to form a TPU/foam core material/enhancement layer PET composite structure of the enhancement layer;

3. gluing the surface of a release film, controlling the coating weight to be 50 mu m thick, and guiding the release film into a six-section oven, wherein the six-section oven is sequentially at 60 ℃, 70 ℃, 85 ℃, 105 ℃ and 120 ℃ and drying time is 6 min; compounding with the second surface of the reinforced layer TPU;

4. coating glue on the surface of the other release film, controlling the thickness of the coating to be 50 mu m, and guiding the release film into a drying oven, wherein the temperatures of the six drying ovens are 60 ℃, 70 ℃, 85 ℃, 105 ℃ and 120 ℃ in sequence, and the drying time is 6 min; is compounded with the second surface of the reinforced layer PET.

Embodiment 2 after peeling off the release layer 6 of the reworked double-sided foam tape, the double-sided pressure-sensitive adhesive layers 5 are respectively bonded with the workpiece, and the reworking method comprises the following steps:

s1: breaking the two foam layers 2 by using a blade from the section of the reworked double-sided foam adhesive tape in the thickness direction of the edge until the elastomer stretching layer 1 at the edge of the reworked double-sided foam adhesive tape is separated from the two foam layers 2 to obtain the reworked double-sided foam adhesive tape shown in figure 4;

s2, clamping and stretching the elastomer stretch layer 1 separated from the foam layer 2 obtained in S1 by hand or a jig, wherein the stretching direction is as shown by an arrow in fig. 4, the elastomer stretch layer 1 deforms and breaks the foam layer 2, and the elastomer stretch layer 1 is separated from the foam layer 2 from the separation position of the elastomer stretch layer 1 and the two foam layers 2 until the elastomer stretch layer 1 is completely separated from the foam layer 2;

s3: the laminate of the pressure-sensitive adhesive layer 5, the PET layer 4 and the residual foam layer 2 was peeled from the surface of one workpiece, and the laminate of the pressure-sensitive adhesive layer 5, the TPU layer 3 and the residual foam layer 2 was peeled from the surface of the other workpiece.

Detecting the performance of a reworked double-sided foam adhesive tape sample by the following detection method:

1. detecting the cohesive force of the reworked double-sided foam adhesive tape:

a1 square inch sample was taken and tested for dynamic shear according to ASTM-D3654.

2. And (4) reworking operation testing:

and (3) respectively bonding a steel plate and a glass plate on two surfaces (the bonding area is 10mm long and 20mm wide) of the reworked double-sided foam tape sample, and performing reworking operation for 20 times on a single sample according to the reworking method.

As shown in FIG. 5, 2-2' sample: 2-2 in the sample reworking operation, S2 inserts the blade between the separated elastic body stretching layer and the foam layer, and intermittently presses the elastic body stretching layer with the blade along the thickness direction of the reworked double-sided foam tape, i.e. the process is repeated in a manner of stretching, pressing and reducing the pressing force, and the double arrows in fig. 5 indicate the direction of the pressing force applied to the blade and the reaction force of the foam layer to the blade when the foam layer recovers its deformation.

And (3) detection results:

1. the cohesion test of the rework double-sided foam tape is shown in the following table:

test specimen	Shear strength (kPa)
		1-1	337
2-1	372
		2-2	383
2-3	379

2. Rework job comparisons are given in the following table:

from the above table, it can be seen that:

1. foaming on the surface of the elastomer stretching layer to prepare a foam layer, wherein the shear strength of the obtained foam adhesive tape is higher, and the cohesion of the foam double-sided adhesive tape is high;

2. the tensile strength or the elongation at break of the elastic body tensile layer is too low, and the breaking probability of the elastic body tensile layer in rework operation is obviously increased;

3. and the 2-2' blade is positioned above the elastic body stretching layer, the elastic body stretching layer is pressed, the foam layer below the elastic body stretching layer is compressed and deformed, the elastic body stretching layer is separated from the foam layer above the elastic body stretching layer, and compared with the reworking operation of a 2-2 sample, the times of fracture of the elastic body stretching layer are obviously reduced.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the technical principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.