CN107201186A - Adhesive tape capable of reducing adhesive force by heating - Google Patents

Abstract

The invention provides an adhesive tape capable of reducing adhesive force by heating, which is characterized in that an adhesive layer mainly composed of resin and foamable material heated to foaming temperature and capable of reducing adhesive force by heating is formed on at least one surface of a base material. When the temperature is lower than the foaming temperature, the adhesion force between the adhesion layer and the stainless steel plate is more than 1.29N/25 mm; when the temperature is higher than the foaming temperature, the adhesion force between the adhesion layer and the stainless steel plate begins to become smaller than 1.0N/25mm in a temperature range. The foaming temperature range falls between 100 ℃ and 200 ℃. By the heating temperature, the adhesive tape is easily peeled from the adherend when the adhesive force is reduced.

Description

Adhesive tape that reduces adhesion when heated

technical field

The invention relates to the field of adhesive tapes whose adhesive force can be reduced by heating, in particular to an adhesive tape containing a foamable material when heated and whose adhesive force can be reduced by heating.

Background technique

The heat-peelable film is a unique film that is sticky at room temperature, and the stickiness will be reduced by heating, and the heat-peelable film can be easily peeled off. The application is very extensive. For example: used for temporary fixation of LEDs, semiconductor chips, etc. for grinding, cutting, heating and fixing processes; temporarily protecting chip circuits or boards from scratches; and between glass and glass in the touch panel process sticky etc. Thermal release film has made a great contribution to automation and labor saving in various processes of electronic components.

Generally, commercially available heat-peelable films basically meet the requirements that they can be bonded like ordinary adhesive films at room temperature, and that the film can be easily peeled off only by heating when it needs to be peeled off. Preferably, the user can select a specific shape for processing of film, roll, label, etc., to save material waste and adapt to the operation of the processing machine. If available, the user can select the heating temperature for peeling. The most important thing is that the adherend will not be damaged when the heat-peelable film is peeled off.

The structural cross-sectional view of a common heat-peelable film is shown in Figure 1. The thermal release film has a substrate layer 1 , a thermal release adhesive layer 2 and a release layer 3 . The base material layer 1 is usually made of fibrous base materials such as non-woven fabrics. The substrate layer 1 is used to carry the heat-peelable adhesive layer 2 and provide the adherend with fixed support strength when it is bonded to the adherend. The release layer 3 is used to protect the heat-peelable adhesive layer 2 from external pollutants before using the heat-peelable film, reduce stickiness and scratch the adherend. It should be noted that, for many prior art or patents, the main difference therebetween is not on the substrate layer 1 and the release layer 3, because the materials used in these items are all existing finished products. The main difference lies in the material used and the manufacturing method of the heat-peelable adhesive layer 2 , the characteristics of the heat-peelable films produced by different technologies will be different, and the application levels will also be different.

Judging from the prior art, many previous cases of heat-peelable adhesive layers can provide references for the industry to make heat-peelable films. For example, Taiwan Patent No. I351425 proposes the use of a thermally expandable adhesive layer containing a foaming agent, which is characterized in that the shear elastic modulus (23°C) of the thermally expandable adhesive layer in an unfoamed state is above 7×106Pa. In addition, in the heat-peelable double-sided pressure-sensitive adhesive sheet proposed in Taiwan Patent No. I428417, one of the heat-peelable pressure-sensitive adhesive layers contains heat-expandable microspheres, and the amount of heat-expandable microspheres is relative to 100 parts by weight The polymer component constituting the heat-peelable pressure-sensitive adhesive layer is 5 to 200 parts by weight.

However, the above-mentioned heat-peelable adhesive layer has many different components and manufacturing methods, and the heat-peelable films produced by them have different viscosities and characteristics during peeling, and are suitable for different heat-peelable films and manufacturing processes.

Contents of the invention

Based on this, the object of the present invention is to provide an adhesive tape whose adhesive force can be reduced by heating, which has different adhesive force before and after thermal peeling, and can be easily peeled off from the adherend after the adhesive force is reduced. To achieve the above object, the technical scheme of the present invention is as follows:

An adhesive tape whose adhesive force can be reduced by heating is formed on at least one side of a base material, and an adhesive layer which can be reduced by heating a foamable material after being heated to a foaming temperature by a resin, when the temperature is lower than At the foaming temperature, the adhesive force between the adhesive layer and the stainless steel plate is greater than 1.29N/25mm; when the temperature is higher than the foaming temperature, the adhesive force between the adhesive layer and the stainless steel plate begins to decrease, Within a certain temperature range, it is less than 1.0N/25mm; the specification of the stainless steel plate is SUS 304, and the surface treatment is carried out according to the Japanese Industrial Standard JIS-Z-0237; the foaming temperature range is between 100°C and 200°C.

Preferably, the resin can be selected from at least one of acrylic resin, polyurethane resin and epoxy resin, and the maintaining time of the foaming temperature can be longer than 3 seconds but shorter than 30 minutes. In addition, the adhesive tape further includes a protective film, which is detachably formed on the side of the adhesive layer different from the substrate. The aforementioned protective film can be made of polyethylene terephthalate (polyethyleneterephthalate, PET), polyethylene (polyethylene, PE), polypropylene (polypropylene, PP), polyethylene 2,6-naphthalate (polyethylene naphthalate) , PEN), polybutyleneterephthalate (PBT), polyvinyl chloride (PVC), polyphenylene sulfide (polyphenylenesulfide, PPS), polyamide (polyamide, PA), polyimide (polyimide, PI), polyethyleneimine (polyethyleneimine, PEI), polycarbonate (polycarbonate, PC), or ethylene/vinyl acetate copolymer (ethylene vinyl acetate, EVA). The protective film can further contain a silicone resin layer, and the substrate can also be replaced by another protective film.

The substrate can be made of polyethylene terephthalate, polyethylene, polypropylene, polyethylene 2,6-naphthalate, polybutylene terephthalate, polyvinyl chloride, polyphenylene sulfide, poly Amide, polyimide, polyethyleneimine, polycarbonate, or ethylene/vinyl acetate copolymer.

The beneficial effects of the present invention are:

The heat-reduced adhesive tape of the present invention has different adhesive strengths before and after thermal peeling, and can be used for processed products that require such adhesive strength.

Description of drawings

Fig. 1 is the structural sectional view of existing heat-peelable film;

Fig. 2 is a structural schematic diagram of an embodiment of the adhesive tape which can reduce the adhesive force by heating according to the present invention;

FIG. 3 is a schematic structural view of another embodiment of the adhesive tape whose adhesive force can be reduced by heating according to the present invention;

Fig. 4 is a structural schematic diagram of another embodiment of the adhesive tape whose adhesive force can be reduced by heating according to the present invention;

in,

1. Substrate layer; 2. Heat-peelable adhesive layer; 3. Release layer;

11. Substrate; 12. Adhesive layer; 13. Protective film.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the adhesive tape of the present invention, which can reduce the adhesive force by heating, will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

The structure of the adhesive tape whose adhesive force can be reduced by heating according to the present invention can be as shown in FIGS. 2 to 4 . In FIG. 2 , the structure of the adhesive tape is that an adhesive layer 12 is formed on one side of a substrate 11 , and a protective film 13 is formed on the adhesive layer 12 . This structure facilitates that when the protective film 13 is torn off, the amorphous adhesive layer 12 can adhere to the substrate 11 and then adhere to the adherend. The adhesive can be further processed by bonding the adhesive tape, such as precision cutting and the like. In Fig. 3, the structure of the adhesive tape is to form a protective film 13 on both sides of the adhesive layer 12. In this structure, one layer of the protective film 13 can be torn off first, and the adhesive layer 12 can be adhered to an adherend; then The other layer of protective film 13 is torn off, and the adhesive layer 12 is adhered to another adherend. Preferably, both stickers have a fixed and conformable shape (for example, a plane), or at least one of them has a fixed shape. Yet another structure of the adhesive tape of the present invention is shown in Figure 4, one layer of adhesive layer 12 is formed on both sides of the base material 11, and then each adhesive layer 12 is different from the side of the base material 11. , forming a protective film 13 . Such a structure enhances the use characteristics of the adhesive tape structure in FIG. 4 , but the mechanical properties of the substrate 11 between the two adhesives must meet the requirements after bonding. According to the spirit of the present invention, if the adhesive tape has two layers of adhesive layers 12, one of them can be made without using the special materials disclosed below.

The aforementioned adhesive tape that can reduce the adhesive force by heating is formed on at least one side of the base material 11. The adhesive layer 12 that can be reduced by heating the foamable material after being heated to a foaming temperature can be formed on at least one side of the base material 11, and then forms a protective tape. film13. The adhesive force of the adhesive layer 12 will vary with temperature. Test with a stainless steel plate: the specification of the stainless steel plate is SUS 304, after the surface treatment is carried out according to the Japanese Industrial Standard JIS-Z-0237, when the temperature of the adhesive tape proposed by the present invention is lower than the foaming temperature, the adhesive layer 12 and the stainless steel plate The adhesive force between the adhesive layer 12 and the stainless steel plate starts to decrease when the temperature is higher than the foaming temperature, and is less than 1.0N/25mm in a temperature range. According to the description of the subsequent embodiments, the foaming temperature range will fall between 100° C. and 200° C. by using different compositions and process methods. In addition, the foaming temperature maintenance time is longer than 3 seconds but shorter than 30 minutes. Before further disclosing the embodiments, each component will be described in detail.

The substrate 11 can be made of polyethylene terephthalate (PET). However, based on different extensibility and temperature properties, polyethylene (polyethylene, PE), polypropylene (polypropylene, PP), polyethylene 2,6-naphthalate (polyethylene naphthalate, PEN), polyparaphenylene Polybutylene terephthalate (PBT), polyvinyl chloride (PVC), polyphenylene sulfide (PPS), polyamide (PA), polyimide (PI) , polyethyleneimine (polyethyleneimine, PEI), polycarbonate (polycarbonate, PC), or ethylene/vinyl acetate copolymer (ethylene vinyl acetate, EVA) is also a material for making the substrate 11 .

The substrate 11 is not necessarily combined with the adhesive layer 12 during the whole bonding and peeling process; the substrate 11 can also be replaced by another protective film 13 . In addition, in order to enhance the characteristics of the base material 11, appropriate plasticizers can be mixed with the above materials, such as phthalates, dimethyl adipate or epoxidized soybean oil, etc., and can also further contain Some additives, such as UV absorbers, surfactants, pigments, dyes, antioxidants, stabilizers, lubricants, etc. The thickness of the substrate 11 is not limited, and generally can be between 50-300 μm.

The aforementioned resin can be selected from at least one of acrylic resin, polyurethane resin and epoxy resin. In order to increase the adhesiveness of the tape, the use of tackifying resin can also be increased. The tackifying resin can be C5 petroleum resin, C9 petroleum resin, esterified rosin, terpene phenolic resin, etc. In addition, a bridging agent can also be added to adjust the adhesion and prevent the occurrence of residual glue. The heatable foamable material is a microsphere with a thermoplastic macromolecular material as an outer shell, and contains liquid hydrocarbons with a low boiling point. The aforementioned hydrocarbons are such as n-pentane (pentane), isobutane (isobutane), propane (propane) and the like. The heated foamable material is affected by the gas or liquid contained in it, and foaming occurs due to thermal expansion or decomposition. After heating and foaming, the surface of the foamable material becomes uneven, which can reduce the contact area between the adhesive layer 12 and the adherend, thereby destroying the adhesive properties of the resin surface, so that the adhesive force can be reduced by heating. The heatable foamable material may be a general commercial product, such as model F-30D or F-100MD manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd., model 051DU40 manufactured by Akzo Nobel, and the like. The present invention does not limit the method of heating to the foaming temperature. Generally, hot plates, hot air circulating ovens, infrared heating devices, tunnel ovens, or other heating methods that provide heat can be used. The thickness of the formed adhesive layer 12 is about 30-50 μm, or thicker, depending on the required specifications.

The protective film 13 is required to be detachably formed on the side of the adhesive layer 12 different from the base material 11 . As mentioned above, under certain special circumstances, the base material 11 can also be replaced by another protective film 13 , so that there are protective films 13 on both sides of the adhesive layer 12 as shown in FIG. 3 . Also because of this, the protective film 13 can be made of the same material as the base material 11 . Preferably, the protective film 13 is made of polyethylene terephthalate or polyethylene release film. However, in actual operation, the protective film 13 preferably contains a silicone resin layer (polyethylene terephthalate release film containing a silicone coating can be used), so as to be easily peeled off from the adhesive layer 12 .

The details of the manufacturing method of the present invention are further described with the following four examples, but the present invention is not limited thereto.

Embodiment one

21.8 parts by weight of heat-expandable microspheres (manufactured by Matsumoto Yuyu Pharmaceutical Co., Ltd., model F-30D), 100.0 parts by weight of an acrylic adhesive (molecular weight is about 600,000, acid value=30mg/g), and tackifying resin (softening point= 150° C.) 21.8 parts by weight, 0.4 parts by weight of bridging agent, 188.8 parts by weight of toluene, and 105.9 parts by weight of ethyl acetate were uniformly mixed and dissolved to prepare a coating solution for the adhesive layer. Coat the prepared glue solution on a polyethylene terephthalate film with a film thickness of 100 μm (manufactured by Nan Ya Plastic Industry Co., Ltd., model BP21), and dry it sufficiently at 70°C to form an adhesive layer with a thickness of 32 μm , affix a silicone resin-treated polyethylene terephthalate film (manufactured by Nan Ya Plastic Industry Co., Ltd., model L138A) with a film thickness of 38 μm, and make a heat-peelable adhesive tape. The test results of the adhesive tape produced according to this embodiment are shown in Table 1.

It can be seen from Table 1 that the heat-peelable adhesive tape in this embodiment has a peel strength of at least 2.72N/25mm at 80°C when heated by a heating plate for 15 seconds to 60 seconds. And above 100°C, the peel strength begins to decrease to below 1.0N/25mm. When the temperature is above 140°C, the peel strength begins to rise, but it does not exceed 1.0N/25mm. Heating in a hot air circulation oven for 1 minute to 30 minutes, the peel strength at 80°C is still at least 2.44N/25mm. And above 100°C, the peel strength begins to decrease to below 1.0N/25mm. And when it reaches 120°C, the peel strength begins to rise; when it reaches 140°C, some parts exceed 1.0N/25mm (heating for 5 minutes, 10 minutes and 30 minutes). It can be seen that the optimum foaming temperature range in this embodiment falls between 100°C and 120°C.

Table 1

Embodiment two

22.1 parts by weight of heat-expandable microspheres (manufactured by AkzoNobel, model 051DU40), 100.0 parts by weight of acrylic adhesive (molecular weight: about 600,000, acid value = 30 mg/g), tackifying resin (softening point = 150°C) 22.1 parts by weight, 0.7 parts by weight of bridging agent, 188.5.1 parts by weight of toluene, and 105.9 parts by weight of ethyl acetate were uniformly mixed and dissolved to make a glue coating solution for the adhesive layer. Coat the prepared glue solution on a polyethylene terephthalate film with a film thickness of 100 μm (manufactured by Nanya Plastic Industry Co., Ltd., model BP21), and dry it sufficiently at 80°C to form an adhesive layer with a thickness of 48 μm , affix a silicone resin-treated polyethylene terephthalate film (manufactured by Nan Ya Plastic Industry Co., Ltd., model L138A) with a film thickness of 38 μm, and make a heat-peelable adhesive tape. The test results of the adhesive tape produced according to this embodiment are shown in Table 2.

It can be seen from Table 2 that the heat-peelable adhesive tape in this embodiment has a peel strength of at least 1.32N/25mm at 100°C when heated by a heating plate for 15 seconds to 60 seconds. And above 120°C, the peel strength begins to decrease to below 1.0N/25mm. At 160°C, the peel strength began to rise, but it has not yet reached 1.0N/25mm. Heating in a hot air circulation oven for 1 minute to 30 minutes, the peel strength at 100°C is still at least 1.29N/25mm. And above 120°C, the peel strength begins to decrease to below 1.0N/25mm, and when it reaches 160°C, the peel strength begins to rise, but it has not yet reached 1.0N/25mm. It can be seen that the optimum foaming temperature range in this embodiment is approximately between 120°C and 160°C.

Table 2

Embodiment Three

22.1 parts by weight of heat-expandable microspheres (manufactured by Matsumoto Yuyu Pharmaceutical Co., Ltd., model F-100MD), 100.0 parts by weight of an acrylic adhesive (molecular weight of about 600,000, acid value=30mg/g), tackifying resin (softening point= 150° C.) 44.1 parts by weight, 0.4 parts by weight of bridging agent, 234.1 parts by weight of toluene, and 105.9 parts by weight of ethyl acetate, all uniformly mixed and dissolved to make a coating solution for the adhesive layer. Coat the prepared glue solution on a polyethylene terephthalate film with a film thickness of 100 μm (manufactured by Nanya Plastic Industry Co., Ltd., model BP21), and dry it sufficiently at 80°C to form an adhesive layer with a thickness of 40 μm , affix a silicone resin-treated polyethylene terephthalate film (manufactured by Nan Ya Plastic Industry Co., Ltd., model L138A) with a film thickness of 38 μm, and make a heat-peelable adhesive tape. The test results of the adhesive tape produced according to this embodiment are shown in Table 3.

It can be seen from Table 3 that the heat-peelable adhesive tape in this embodiment has a peel strength of at least 1.29N/25mm at 120°C when heated by a heating plate for 15 seconds to 60 seconds. And above 140°C, the peel strength begins to decrease to below 1.0N/25mm. And when it reached 180°C, the peel strength began to rise (heating for 15 seconds, 30 seconds, 45 seconds and 60 seconds), but it did not exceed 1.0N/25mm. Heating in a hot air circulation oven for 1 minute to 30 minutes, the peel strength at 120°C is still at least 1.95N/25mm. And above 140°C, the peel strength begins to decrease to below 1.0N/25mm. However, when the temperature reached 180°C, the peel strength began to rise (it occurred after heating for more than 1 minute), but it did not exceed 1.0N/25mm. It can be seen that the optimum foaming temperature range in this embodiment is approximately between 140°C and 180°C.

table 3

Embodiment four

14.7 parts by weight of heat-expandable microspheres (manufactured by Sekisui Chemical Industry Co., Ltd., model EM-501), 100.0 parts by weight of an acrylic adhesive (molecular weight of about 600,000, acid value = 30 mg/g), tackifying resin (softening point = 150° C.) 22.1 parts by weight, 0.9 parts by weight of bridging agent, 173.5 parts by weight of toluene, and 105.9 parts by weight of ethyl acetate were uniformly mixed and dissolved to prepare a coating solution for the adhesive layer. Coat the prepared glue solution on a polyethylene terephthalate film with a film thickness of 38 μm (manufactured by Nan Ya Plastic Industry Co., Ltd., model BP21), and dry it sufficiently at 80°C to form an adhesive layer with a thickness of 48 μm , affix a silicone resin-treated polyethylene terephthalate film (manufactured by Nan Ya Plastic Industry Co., Ltd., model L138A) with a film thickness of 38 μm, and make a heat-peelable adhesive tape. The test results of the adhesive tape produced according to this embodiment are shown in Table 4.

It can be seen from Table 4 that the heat-peelable adhesive tape in this example is heated by a heating plate for 15 seconds to 60 seconds. At 140°C, the peel strength is always above 6.78N/25mm; at 160°C, The peel strength starts to decrease to less than 1.0N/25mm, and remains the same up to 200°C. Use a hot air circulation oven to heat for 1 minute to 30 minutes. Except for heating at 120°C for 30 minutes, in the rest of the heating time, the peel strength begins to decrease to below 1.0N/25mm at 160°C (heating for 30 minutes). At 180°C, the peel strength is below 1.0N/25mm, and it remains the same up to 200°C. It can be seen that the optimum foaming temperature range in this embodiment falls between 180°C and 200°C.

Table 4

The above-mentioned embodiments only express several implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but should not be construed as limiting the patent scope of the present invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (8)

1. An adhesive tape capable of reducing adhesive force by heating, which is formed with an adhesive layer capable of reducing adhesive force by heating a resin and a foamable material after heating to a foaming temperature on at least one side of a base material, characterized in that: when the temperature is lower than the foaming temperature, the adhesion force between the adhesion layer and the stainless steel plate is more than 1.29N/25 mm; when the temperature is higher than the foaming temperature, the adhesive force between the adhesive layer and the stainless steel plate begins to be reduced and is less than 1.0N/25mm in a temperature interval; the stainless steel plate is SUS 304 in specification, and is subjected to surface treatment according to Japanese Industrial Standard JIS-Z-0237; the foaming temperature range is between 100 ℃ and 200 ℃.

2. The adhesive tape according to claim 1, wherein the resin is at least one selected from the group consisting of acryl resin, urethane resin and epoxy resin.

3. The adhesive tape according to claim 1, wherein the foaming temperature is maintained for a period of time longer than 3 seconds and shorter than 30 minutes.

4. The adhesive tape of claim 1, further comprising a protective film detachably disposed on a side of the adhesive layer different from the substrate.

5. The adhesive tape according to claim 4, wherein the protective film is made of polyethylene terephthalate, polyethylene, polypropylene, polyethylene-2, 6-naphthalate, polybutylene terephthalate, polyvinyl chloride, polyphenylene sulfide, polyamide, polyimide, polyethyleneimine, polycarbonate, or ethylene/vinyl acetate copolymer.

6. The adhesive tape of claim 4, wherein the protective film has a silicone layer thereon.

7. The adhesive tape according to claim 4, wherein the substrate is replaced with another protective film.

8. The adhesive tape according to claim 1, wherein the substrate is made of polyethylene terephthalate, polyethylene, polypropylene, polyethylene-2, 6-naphthalate, polybutylene terephthalate, polyvinyl chloride, polyphenylene sulfide, polyamide, polyimide, polyethyleneimine, polycarbonate, or ethylene/vinyl acetate copolymer.