JP2018178025A - Thermal adhesion tape, and manufacturing method of thermal adhesion tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate less thermal adhesion tape or the like, promoting cure of an adhesive layer when heated, in which the adhesive layer is hardly cured without heating such as during storage.SOLUTION: A substrate is not arranged in a thermal adhesion tape 1, and the thermal adhesion tape 1 joints an adherend by thermal compression bond, and has an adhesive layer 3 containing an acrylonitrile-butadiene rubber, a phenol resin, peroxide generating acid due to decomposition, and a phenol resin crosslinking agent. The peroxide has half-life temperature of 130°C to 170°C, and the adhesive layer 3 contains peroxide of 0.5 pts.mass to 5 pts.mass based on 100 pts.mass of the acrylonitrile-butadiene rubber.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a thermal adhesive tape and the like. More specifically, the present invention relates to a thermal adhesive tape or the like which is not provided with a base material and is attached to a glass cloth or the like in a use mode, ie, a mode in which adherends are joined.

  2. Description of the Related Art Conventionally, a thermal adhesive tape has been known in which an adhesive layer is cured by thermocompression bonding to bond adherends. This thermal adhesive tape is used for applications such as bonding an adherend such as glass cloth to each of one surface and the other surface of the adhesive layer by heat and pressure bonding and joining the adherends, etc. Ru.

In Patent Document 1, an adhesive tape for a semiconductor device contains an acrylonitrile-butadiene copolymer, a novolak-type phenol resin, and an epoxy resin in an adhesive layer, and in order to enable NBR to be self-crosslinked at the time of heating. It is disclosed to contain dialkyl peroxides and the like.
Patent Document 2 discloses a curable resin composition comprising an organic peroxide such as vinylbenzyl etherified novolak resin, novolak type or resol type phenol resin, dicumyl peroxide and the like, and hexamethylenetetramine.
Patent Document 3 discloses a sealing agent for a liquid crystal display cell, which contains a partially esterified epoxy (meth) acrylate resin, an organic peroxide such as octanoyl peroxide, a phenol resin, and an organosilicon compound.

Unexamined-Japanese-Patent No. 5-291360 Japanese Patent Application Laid-Open No. 6-329875 JP-A-9-194567

In order to achieve adhesion of the thermal adhesive tape to the adherend in a short time, an acid is contained in the adhesive layer, and during heating and pressure bonding of the thermal adhesive tape, the acid causes, for example, phenolic resin contained in the adhesive layer. By promoting the reaction between the acid and the crosslinking agent (curing agent), the curing of the adhesive layer may be accelerated.
However, when the adhesive layer contains an acid, the acid gradually promotes the reaction between the phenol resin and the crosslinking agent even when the thermal adhesive tape is not heated, for example, when the thermal adhesive tape is stored. And curing of the adhesive layer may progress. When the curing of the adhesive layer has already progressed before the thermocompression bonding of the thermal adhesive tape, the adhesion of the thermal adhesive tape to the adherend can not be sufficiently obtained even if the adherend is thermocompression bonded to the thermal adhesive tape There is a fear.
An object of the present invention is to provide a substrateless thermal adhesive tape or the like in which the curing of the adhesive layer when heated is promoted and the adhesive layer is not easily cured when not heated at the time of storage or the like.

  The thermal adhesive tape of the present invention is a so-called substrateless thermal adhesive tape in which a substrate is not provided and an adherend is joined by heating and pressure bonding, which is an acrylonitrile-butadiene rubber, phenol resin, decomposition It is characterized in that it is a thermal adhesive tape provided with an adhesive layer containing a peroxide which generates an acid due to the reaction and a phenolic resin crosslinking agent.

  Here, the heat adhesive tape preferably further comprises a release liner provided on at least one surface of the adhesive layer and releasable from the adhesive layer.

  The peroxide preferably has a half-life temperature of 130 ° C. or more and 170 ° C. or less.

  The adhesive layer can contain peroxide in an amount of 0.5 parts by mass or more and 5 parts by mass or less, based on 100 parts by mass of the acrylonitrile-butadiene rubber.

  Further, the method for producing a substrateless thermal adhesive tape according to the present invention, wherein a substrate is not provided and the adherend is joined by heat and pressure bonding, a release liner preparation step of preparing a release liner, and acrylonitrile- An adhesive layer forming step of applying an adhesive layer solution containing a butadiene rubber, a phenolic resin, a peroxide that generates an acid due to decomposition, and a phenolic resin crosslinking agent to a release liner, and forming an adhesive layer; It is characterized by including.

  According to the present invention, it is possible to provide a substrateless thermal adhesive tape or the like in which the curing of the adhesive layer when heated is promoted and the adhesive layer is hardly cured when not heated at the time of storage or the like.

It is sectional drawing shown about the heat adhesive tape to which this Embodiment is applied. It is a flowchart explaining the manufacturing method of a heat adhesive tape.

  Hereinafter, modes for carrying out the present invention will be described in detail. The present invention is not limited to the following embodiments. Moreover, it can variously deform and implement within the range of the summary. Further, the drawings used are for describing the present embodiment, and do not represent actual sizes.

<Description of the overall configuration of the thermal adhesive tape>
FIG. 1 is a cross-sectional view showing a thermal adhesive tape 1 to which the present embodiment is applied.
The illustrated thermal adhesive tape 1 includes an adhesive layer 3 and a release liner 2 provided on one surface side of the adhesive layer 3. After the heat adhesive tape 1 is attached to the adherend, the release liner 2 can be peeled off. Although not illustrated, in FIG. 1, another release liner or the like may be provided on the side opposite to the release liner 2 of the adhesive layer 3.

  The thermal adhesive tape 1 bonds the adherend by heat and pressure bonding. Specifically, for example, when the adherend is a glass cloth, in a manufacturing process of manufacturing the glass cloth, end portions of a roll-shaped raw fabric obtained by winding up a long glass cloth are joined, etc. It is used for the purpose. At this time, the adhesive layer 3 from which the release liner 2 has been peeled is held between the end portions of the roll-shaped raw fabric, and this portion is pressed while being heated. Thereby, the adhesive layer 3 is cured, and the end portions of the roll-shaped raw fabric are joined via the heat adhesive tape 1. That is, the thermal adhesive tape 1 of the present embodiment can not bond the adherends unless the thermocompression bonding is performed, and is different from the pressure-sensitive adhesive tape which bonds the adherends by the adhesive force.

<Peeling liner>
The release liner 2 is used when manufacturing the heat adhesive tape 1, and the adhesion of the adhesive layer 3 is required to be maintained by suppressing adhesion of dust and the like to the adhesive layer 3. Although what can be used as a release liner is not particularly limited, examples thereof include synthetic resins such as polyethylene, polypropylene and polyethylene terephthalate, and papers. Further, in order to enhance the releasability of the adhesive layer 3, the surface of the release liner may be subjected to release treatment with a silicone release treatment agent, a long chain alkyl release treatment agent, a fluorine release treatment agent, or the like. The thickness of the release liner is not particularly limited, but one having a thickness of 10 μm to 200 μm can be suitably used.

<Adhesive layer>
The adhesive layer 3 is a functional layer that hardens by heating and exerts an adhesive force between the thermal adhesive tape 1 and the adherend by being pressurized at that time.
In the thermal adhesive tape 1 of the present embodiment, the thickness of the adhesive layer 3 is preferably 25 μm or more and 200 μm or less. When the thickness of the adhesive layer 3 is less than 25 μm, it is difficult to maintain the strength against the shear force. Here, the shear force is a force in the direction along the surface of the heat adhesive tape.
When the thickness of the adhesive layer 3 exceeds 200 μm, the diameter of the roll becomes excessively large or wrinkles easily occur when the heat adhesive tape 1 is wound to form a roll product. In addition, the solvent tends to remain in the process of manufacturing the thermal adhesive tape 1, and the surface of the adhesive layer 3 is easily made uneven, so that the appearance tends to be deteriorated.

  Moreover, in the present embodiment, the adhesive layer 3 contains an acrylonitrile-butadiene rubber, a phenol resin, a peroxide, and a phenol resin crosslinking agent.

The structure of the acrylonitrile-butadiene rubber is not particularly limited. For example, any of linear acrylonitrile-butadiene rubber and acrylonitrile-butadiene rubber having a branched structure can be used. However, in the present embodiment, it is more preferable to use an acrylonitrile-butadiene rubber having a branched structure.
The acrylonitrile-butadiene rubber having a branched structure can impart an extremely high cohesion to the adhesive layer 3 while at the same time imparting appropriate flexibility. Among the acrylonitrile-butadiene rubbers, the acrylonitrile-butadiene rubber having a branched structure used in the present embodiment is classified into a hot rubber produced at a polymerization temperature of 25 ° C. to 50 ° C., for example, It is represented by the following chemical formula 1.

Moreover, General formula (1) of following Chemical formula 2 is structural formula of a linear acrylonitrile-butadiene rubber. Here, m and n are integers of 1 or more. In the acrylonitrile-butadiene rubber having a branched structure represented by the chemical formula 1, a double bond of butadiene in the general formula (1) is cleaved and a structure further represented by the general formula (1) is bonded thereto It is. That is, each line represented by a curve in Formula 1 has a structure represented by the general formula (1).
In this embodiment, as the acrylonitrile-butadiene rubber having a branched structure, for example, one having a weight average molecular weight (Mw) of 300,000 can be used.

  The phenol resin imparts thermosetting, heat resistance and adhesiveness to the adhesive layer 3. The phenol resin used in the present embodiment is not particularly limited, but a novolak resin in which phenols and formaldehyde are synthesized under an acid catalyst can be suitably used. Examples of phenols include phenol, cresol, xylenol, alkylphenol, halogenated phenol, arylphenol, aminophenol, nitrophenol, bisphenol A, polyhydric phenol, derivatives of these, and the like. Moreover, these can be used individually or in mixture of 2 or more types.

The peroxide is thermally decomposed when the heat adhesive tape 1 is heated, and crosslinks the acrylonitrile-butadiene rubber by the generated free radicals.
Here, in the present embodiment, a peroxide that generates an acid due to decomposition can be suitably used. That is, when the peroxide is contained in the adhesive layer 3, the speed at which the adhesive layer 3 cures when the thermal adhesive tape 1 is heated is improved. Specifically, when the thermal adhesive tape 1 of the present embodiment is heated, as described above, first, the peroxide is thermally decomposed, and the free radical generated causes crosslinking of the acrylonitrile-butadiene rubber. At this time, free radicals react with hydrogen extracted from the acrylonitrile-butadiene rubber to form an acid. Then, the reaction between the phenol resin and the phenol resin crosslinking agent is promoted by the acid to cause the crosslinking of the phenol resin to accelerate the curing of the phenol resin, whereby the speed at which the adhesive layer 3 cures is improved.

  On the other hand, the peroxide contained in the adhesive layer 3 of the present embodiment is unlikely to be decomposed and does not easily generate an acid when the thermal adhesive tape 1 is not heated in a room temperature environment or the like. Also, the peroxide itself does not directly affect the reaction of the phenolic resin. Therefore, when the heat adhesive tape 1 is not heated, it is difficult for the phenol resin to be cured.

The peroxide preferably has a half-life temperature of 130 ° C. or more and 170 ° C. or less.
Here, the half-life temperature means a temperature at which when the peroxide is heated for 1 minute, the concentration of the peroxide is halved from the concentration just before the heating due to decomposition of the peroxide.

When the half-life temperature of the peroxide is higher than 170 ° C., the rate of decomposition of the peroxide is slow when the peroxide is heated, and the acid is less likely to be generated. In this case, it is difficult to accelerate the curing of the phenol resin when the heat adhesive tape 1 is heated.
When the half-life temperature of the peroxide is lower than 130 ° C., the peroxide is decomposed to easily generate an acid even when the peroxide is not heated. In this case, curing of the phenol resin is likely to proceed even when the thermal adhesive tape 1 is not heated, for example, when the thermal adhesive tape 1 is stored.

Moreover, it is preferable that the contact bonding layer 3 contains 0.5 mass part or more and 5 mass parts or less of peroxides, when an acrylonitrile- butadiene rubber is 100 mass parts.
If the amount of the peroxide is less than 0.5 parts by mass, the amount of acid generated from the peroxide is small, and curing of the phenol resin when the thermal adhesive tape 1 is heated is hardly promoted.
When the amount of the peroxide is more than 5 parts by mass, the amount of the generated acid is increased by the gradual decomposition of the peroxide when the peroxide is not heated. In this case, curing of the phenol resin is likely to proceed even when the thermal adhesive tape 1 is not heated, for example, when the thermal adhesive tape 1 is stored.

  As a peroxide that generates an acid due to decomposition, diacyl peroxide and peroxy ester can be suitably used. In the present embodiment, these can be used alone or in combination of two or more. Examples of the diacyl peroxide include Nipar (registered trademark) BMT and Parroyl (registered trademark) L manufactured by NOF Corporation. Moreover, as peroxy ester, Perbutyl (registered trademark) O, Perbutyl Z, etc. by NOF Corporation are mentioned, for example.

  When the heat adhesive tape 1 is heated, the phenol resin crosslinking agent causes an addition condensation reaction with the phenol resin to cure the phenol resin in a shorter time. The phenol resin crosslinking agent is also called a crosslinking accelerator for phenol resin and a curing agent. Examples of the phenol resin crosslinking agent include hexamethylenetetramine (hexamine), methylolmelamine and methylolurea. Moreover, these can be used individually or in mixture of 2 or more types. Among the above, hexamethylenetetramine (hexamine) can be suitably used in the present embodiment.

  Adhesive layer 3 may further contain other resins, rubbers, and the like within the scope of the gist of the present embodiment. Moreover, even if it contains a thickener in order to improve the coating property at the time of applying the solution for adhesive layers which is a coating liquid mentioned later, and the antifoamer for suppressing foaming and suppressing the roughening of an external appearance. Good.

<Method of manufacturing thermal adhesive tape>
FIG. 2 is a flowchart illustrating the method of manufacturing the thermal adhesive tape 1.
First, the release liner 2 is prepared (step 101: release liner preparation step).

  Next, an adhesive layer solution for applying the adhesive layer 3 is prepared (step 102: adhesive layer solution preparation process). This adhesive layer solution contains the above-mentioned acrylonitrile-butadiene rubber, a phenol resin, a peroxide, and a phenol resin crosslinking agent, and these are charged into a predetermined solvent and then stirred. In addition, you may use a commercial item as this solution for adhesive layers.

Then, the adhesive layer solution is applied to the release liner 2 to form a coating film (step 103).
Further, by drying the coated film, the adhesive layer 3 is formed on the release liner 2 (step 104). The process of step 103 and step 104 can be considered as an adhesive layer forming process of applying the adhesive layer solution to the release liner 2 to form the adhesive layer 3.

By the steps described above, the thickness of the adhesive layer 3 can be made 25 μm or more and 200 μm or less, and the thermal adhesive tape 1 of the present embodiment can be manufactured.
According to the embodiment described above in detail, it is possible to provide the substrateless thermal adhesive tape 1 in which the substrate is not provided.

In addition, when the adherend is heated and pressure-bonded to the thermal adhesive tape 1, the peroxide contained in the adhesive layer 3 is decomposed to generate an acid, and the acid cures the phenol resin and the phenol resin crosslinking agent. Promote. Therefore, the speed at which the adhesive layer 3 cures is improved, and the thermal adhesive tape 1 adheres to the adherend in a short time.
On the other hand, when the thermal adhesive tape 1 is not heated, the decomposition of the peroxide is difficult to occur and the acid is hard to be generated, so the curing of the adhesive layer 3 hardly progresses. Therefore, during storage without using the thermal adhesive tape 1, the adhesive strength of the thermal adhesive tape 1 is unlikely to be lost.

  Hereinafter, the present invention will be described in more detail using examples. The present invention is not limited by these examples unless the gist is exceeded.

The thermal adhesive tape 1 shown in FIG. 1 was produced and evaluated. The execution conditions and the evaluation results are shown in Table 1 below.
[Preparation of Thermal Adhesive Tape 1]
Example 1
In the present embodiment, as the release liner 2, one having a thickness of 120 μm was used. The adhesive layer 3 was formed on one side of the release liner 2 as follows.
First, ethyl acetate is used as a solvent, and an acrylonitrile-butadiene rubber having a branched structure, a phenol resin, a peroxide, and a phenol resin crosslinking agent are added to this solvent and dissolved by stirring, and the solid content concentration is 40 mass% An adhesive layer solution was prepared. At this time, Nipol (registered trademark) 1001LG manufactured by Nippon Zeon Co., Ltd. was used as the acrylonitrile-butadiene rubber having a branched structure. Moreover, as the phenol resin, Tamanor (registered trademark) 531 manufactured by Arakawa Chemical Industries, Ltd. was used. In addition, 9 mass% of hexamethylene tetramines (hexamines) are contained in tamanol 531 as a phenol resin crosslinking agent. Further, the mass ratio of the acrylonitrile-butadiene rubber having a branched structure and the phenol resin was 100/120. In addition, Niper BMT manufactured by NOF Corporation was used as the peroxide.

General formula (2) of following Chemical formula 3 is a structural formula of nyper BMT. Moreover, General formula (3) of following Chemical formula 4 is a reaction formula when heating and decomposing nyper BMT, Comprising: The reaction formula when the benzoyl peroxide which is a part of structure of nyper BMT decomposes | disassembles It is. When the benzoyl peroxide in the general formula (3) is heated, the oxygen-oxygen bond is cleaved to generate 2 equivalents of phenyl radicals to benzoyl peroxide, and each phenyl radical becomes benzoic acid. That is, when benzoyl peroxide is thermally decomposed, two equivalents of acid are generated with respect to this benzoyl peroxide. Further, when benzoyl-m-methyl benzoyl peroxide, which is another part of the structure of nyper BMT in the general formula (2), is thermally decomposed, two equivalents of acid are generated with respect to the benzoyl-m-methyl benzoyl peroxide. In addition, when m-toluoyl peroxide, which is another part of the structure of nyper BMT in the general formula (2), is thermally decomposed, two equivalents of acid are generated with respect to this m-toluoyl peroxide. That is, thermal decomposition of nyper BMT generates 2 equivalents of acid to this niper BMT.
The half-life temperature of nyper BMT is 131 ° C. The adhesive layer 3 contained 3 parts by mass of nyper BMT when 100 parts by mass of the acrylonitrile-butadiene rubber was used.

Then, the adhesive layer solution was applied onto the release liner 2 and dried to form an adhesive layer 3. The thickness of the adhesive layer 3 was 50 μm.
The thermal adhesive tape 1 of this example was produced by the above steps.

(Examples 2 to 8)
A thermal adhesive tape 1 was produced in the same manner as in Example 1 except that changes were made to Example 1 as shown in Table 1.
That is, in Examples 2, 3 and 6, those in which the type of peroxide contained in the adhesive layer 3 was changed were used. Specifically, in Example 2, Perbutyl O manufactured by NOF Corporation was used. The general formula (4) of the following chemical formula 5 is a structural formula of 2-ethylhexanoyl-t-butylperoxide as perbutyl O. When 2-ethylhexanoyl-t-butylperoxide in general formula (4) is heated, the oxygen-oxygen bond is cleaved to generate one equivalent of radical to 2-ethylhexanoyl-t-butylperoxide, and this radical Becomes a carboxylic acid. That is, when perbutyl O is pyrolyzed, one equivalent of acid is generated with respect to this perbutyl O. The half-life temperature of Perbutyl O is 134 ° C. The adhesive layer 3 contained 3 parts by mass of perbutyl O, based on 100 parts by mass of acrylonitrile-butadiene rubber.

  In Example 3, Perbutyl Z manufactured by NOF Corporation was used. Formula (5) of the following formula 6 is a structural formula of t-butyl benzoyl peroxide as perbutyl Z. When t-butyl benzoyl peroxide in the general formula (5) is heated, the oxygen-oxygen bond is cleaved to generate one equivalent of a radical to t-butyl benzoyl peroxide, which becomes a carboxylic acid. That is, when Perbutyl Z is pyrolyzed, one equivalent of acid is generated with respect to this Perbutyl Z. The half-life temperature of Perbutyl Z is 167 ° C. The adhesive layer 3 contained 3 parts by mass of perbutyl Z, based on 100 parts by mass of acrylonitrile-butadiene rubber.

  In Example 6, peroyl L manufactured by NOF Corporation was used. General formula (6) of the following formula 7 is a structural formula of dododecanoyl peroxide as peroyl L. When the dododecanoyl peroxide in the general formula (6) is heated, the oxygen-oxygen bond is cleaved to form radicals equivalent to 2 equivalents to the dododecanoyl peroxide, and each radical becomes a carboxylic acid. That is, when peroyl L is pyrolyzed, two equivalents of acid are generated with respect to this peroyl L. The half-life temperature of peroyl L is 116 ° C. The adhesive layer 3 contained 3 parts by mass of peroyl L, based on 100 parts by mass of the acrylonitrile-butadiene rubber.

  In Examples 4 and 5, the amount of peroxide contained in the adhesive layer 3 was changed. Specifically, in Example 4, when the amount of the acrylonitrile-butadiene rubber was 100 parts by mass, 0.4 parts by mass of nyper BMT was included. In Example 5, 6 parts by mass of nyper BMT was included when 100 parts by mass of the acrylonitrile-butadiene rubber was used.

  In Examples 7 and 8, the thickness of the adhesive layer 3 was changed. Specifically, in Example 7, the thickness of the adhesive layer 3 was 25 μm. Furthermore, in Example 8, the thickness of the adhesive layer 3 was 200 μm.

(Comparative Examples 1 to 3)
A thermal adhesive tape 1 was produced in the same manner as in Example 1 except that changes were made to Example 1 as shown in Table 1.
That is, in Comparative Example 1, the adhesive layer 3 contains no peroxide.
Moreover, in Comparative Example 2, benzoic acid as a substitute for peroxide is contained in the adhesive layer 3. Specifically, when 100 parts by mass of acrylonitrile-butadiene rubber was used, 3 parts by mass of benzoic acid was included.
In Comparative Example 3, Perhexyl (registered trademark) I manufactured by NOF Corporation was used as a peroxide. The general formula (7) of the following formula 8 is a structural formula of t-hexylperoxyisopropyl monocarbonate as perhexyl I. Heating t-hexylperoxyisopropyl monocarbonate in the general formula (7) generates radicals and carbon dioxide but does not generate an acid. The half-life temperature of Perhexyl I is 155 ° C. The adhesive layer 3 contained 3 parts by mass of perhexyl I, based on 100 parts by mass of the acrylonitrile-butadiene rubber.

  As evaluation about Examples 1-8 and Comparative Examples 1-3, evaluation of the adhesive force about the heat adhesive tape before storage (adhesive force evaluation before storage), and the insoluble matter about the heat adhesive tape before storage Evaluation (insoluble content evaluation before storage) was performed. Moreover, evaluation of the adhesive force about the thermal adhesive tape after storage (adhesive force evaluation after storage), and evaluation of the insoluble part about the thermal adhesive tape after storage (an insoluble part evaluation after storage) were performed.

[Method of adhesive strength evaluation before storage]
As evaluation of the adhesive force about the heat adhesive tape of Examples 1-8 and Comparative Examples 1-3, shear force was applied to the heat adhesive tape, and the adhesive force with respect to this was evaluated.
Specifically, two glass cloths were prepared, and the heat adhesive tape was sandwiched between the two glass cloths, and the two glass cloths were joined with the heat adhesive tape by thermocompression bonding. The thickness of the glass cloth used for evaluation is 0.17 mm, and the breaking strength is about 300 N / 10 mm.
In addition, what bonded the glass cloth with the heat | fever adhesive tape was prepared on the conditions of two types of thermocompression bonding. Specifically, the glass cloth is bonded with a thermal adhesive tape by pressing at 160 ° C. and a pressure of 1.47 × 10 ⁵ N / m ² for 20 seconds, 170 ° C. and 1.47 × 10 ⁵ N / m. Pressing was performed for 10 seconds at a pressure of m ² to prepare a glass cloth bonded with a heat adhesive tape.

  Then, the two glass cloths, which are the adherends produced, are pulled at a tensile speed of 200 mm / min, and under this condition, whether or not the glass cloth is broken before peeling occurs between the glass cloth and the thermal adhesive tape The evaluation of adhesion to shear force was carried out. That is, with regard to adhesion, it means that when the glass cloth is broken before the peeling occurs between the glass cloth and the heat adhesive tape, the shear force is greater than the breaking strength of the glass cloth at this time. It was evaluated as pass, and when peeling occurred, it was evaluated as fail.

[Method of evaluating insoluble content before storage]
Moreover, the insoluble part of the heat adhesive tape after thermocompression bonding was evaluated as evaluation of the speed | rate which an adhesive layer hardens | cures at the time of thermocompression bonding about the heat adhesive tape of Examples 1-8 and Comparative Examples 1-3. Here, the insoluble content of the thermal adhesive tape means the ratio of the weight of the thermal adhesive tape not dissolved in the solvent to the total weight of the thermal adhesive tape.
The product formed by the reaction of the acid and the phenolic resin has the property of being insoluble in the solvent. Therefore, it is considered that as the amount of undissolved matter of the heat adhesive tape after thermocompression bonding increases, more acid is generated at the time of thermocompression bonding and the reaction proceeds. The greater the amount of acid generated during thermocompression bonding, the faster the rate at which the adhesive layer cures.

As a specific evaluation method of the insoluble content of the heat adhesive tape after heat pressure bonding, first, two release liners made of polyethylene terephthalate are prepared, and the heat adhesive tape is sandwiched between the two release liners, and the heat adhesive pressure is obtained by The two release liners were joined with a thermal adhesive tape.
In addition, the conditions of thermocompression bonding were the same as the conditions of thermocompression bonding in adhesive force evaluation before storage. That is, one obtained by pressing the adhesive at 160 ° C. and a pressure of 1.47 × 10 ⁵ N / m ² for 20 seconds and bonding the release liner with a thermal adhesive tape, 170 ° C. and 1.47 × 10 ⁵ N / m ² The pressure was applied for 10 seconds to prepare a release liner bonded with a heat adhesive tape.

Subsequently, the release liner was peeled off from the heat adhesive tape, and the weight of the heat adhesive tape from which the release liner was peeled off was measured, and the measured value was set to W1. The heat adhesive tape used had a weight of about 0.1 g to 0.2 g.
Thereafter, the heat adhesive tape was immersed in 10 g to 20 g of methyl ethyl ketone as a solvent, and stirred with a mix rotor for 24 hours. Subsequently, the solution was filtered using a stainless steel mesh to extract insolubles of the heat adhesive tape. The stainless steel mesh used was 100 mesh. The weight of this mesh when not in use is taken as weight W2.
Thereafter, the mesh in which the insoluble matter of the heat adhesive tape remains is dried by an explosion-proof dryer under an environment of 80 ° C. and then allowed to cool. Subsequently, the weight of this mesh was measured, and the measured value was set to W3. And the insoluble part computed from ((W3-W2) / W1) was evaluated. In addition, as for the heat adhesive tapes of Examples 1 to 8 and Comparative Examples 1 to 3, the insolubles before the heat and pressure bonding were all 0%.

[Method for evaluating adhesion after storage]
Moreover, it evaluated about the adhesive force after the storage for a fixed period about the heat adhesive tape of Examples 1-8 and Comparative Examples 1-3.
Specifically, the thermal adhesive tapes of Examples 1 to 8 and Comparative Examples 1 to 3 were stored for 1 week in an environment of 80 ° C. after producing the thermal adhesive tapes. Then, the two glass cloths are joined with the heat adhesive tape after storage by thermocompression bonding under the same conditions as the method of adhesive strength evaluation before storage, and the shear force is applied to the two glass cloths which are adherends. Was added to evaluate the adhesion to this.

[Method of evaluating insoluble content after storage]
Furthermore, in order to evaluate the degree of curing of the adhesive layer when the thermal adhesive tape is stored without heat and pressure bonding, the thermal adhesive tapes of Examples 1 to 8 and Comparative Examples 1 to 3 have a fixed period of time. The insoluble content after storage was evaluated.
It is considered that as the amount of insoluble matter after storage of the thermal adhesive tape increases, more acid is generated from the peroxide contained in the adhesive layer during storage, and the reaction proceeds. The more acid generated during storage, the greater the degree to which the adhesive layer cures before thermocompression bonding.

As a specific evaluation method of the insoluble matter after storage of the heat adhesive tape, the heat adhesive tapes of Examples 1 to 8 and Comparative Examples 1 to 3 are prepared under the environment of 80 ° C. after preparation of these heat adhesive tapes. It was stored for a week, and the weight of the heat adhesive tape after this storage was set to W4.
Thereafter, the insoluble portion of the heat adhesive tape was extracted using a stainless steel mesh by the same method as the method for evaluating the insoluble portion before storage. However, in the evaluation of insoluble content after storage, in order to evaluate the amount of acid generated during storage, unlike the evaluation of insoluble content before storage, the insoluble content of the thermal adhesive tape not subjected to heat and pressure bonding is extracted. .
Then, assuming that the weight of the mesh when not in use is weight W5, and the weight of the mesh in which the insoluble matter of the thermal adhesive tape remains is weight W6, the insoluble matter calculated from ((W6-W5) / W4) is evaluated.

〔Evaluation results〕
The evaluation results of adhesion are shown in Table 1.
As shown in Table 1, as for the thermal adhesive tapes 1 of Examples 1 to 8, all of the ones produced by thermocompression bonding under any conditions were all for each of the adhesion before storage and the adhesion after 1 week storage. It was a pass.
Moreover, about the heat adhesive tape 1 of Examples 1-8, the insoluble content before storage also increases large also by what was produced by the thermocompression bonding on any conditions, and hardening of the adhesive layer 3 at the time of thermocompression bonding is carried out. It is considered to be promoted. Furthermore, it is considered that the increase in the insoluble content of the thermal adhesive tape 1 after storage for one week is suppressed, and the curing of the adhesive layer 3 during storage is difficult to proceed.

In Comparative Example 1 and Comparative Example 3, on the heat adhesive tape before storage, cohesive failure occurred in the adhesive layer and peeling of the heat adhesive tape occurred. Moreover, in this comparative example 1 and the comparative example 3, about the heat adhesive tape before storage, the insoluble content after thermocompression bonding hardly increased.
Regarding this, in Comparative Example 1, peroxide is not used originally, and in Comparative Example 3, although peroxide is used, this peroxide does not generate an acid due to decomposition. Therefore, in both of Comparative Examples 1 and 3, no acid is generated at the time of thermocompression bonding of the heat adhesive tape, crosslinking of the phenol resin does not proceed sufficiently, and curing of the adhesive layer is insufficient. Thus, it is considered that the adhesion of the thermal adhesive tape to the adherend was not sufficiently obtained.

Further, in Comparative Example 2, the adhesive strength of the heat adhesive tape before storage was passed, but with respect to the heat adhesive tape after storage for 1 week, interfacial failure occurred in the adherend and peeling of the heat adhesive tape occurred. . Moreover, in this comparative example 2, although the undissolved part after pressure bonding increased largely about the heat adhesive tape before storage, the undissolved part about the heat adhesive tape after one week storage increases greatly. Was.
It is considered that, during the storage of the heat adhesive tape for one week, the benzoic acid and the phenol resin react, the crosslinking of the phenol resin proceeds, and the curing of the adhesive layer progresses. Then, even if the adherend is heated and pressure-bonded to the thermal adhesive tape after curing of the adhesive layer proceeds sufficiently, it is considered that the adhesive strength of the thermal adhesive tape to the adherend is not sufficiently obtained.

  From the results of Examples 1 to 8 and Comparative Examples 1 to 3, it is confirmed that the adhesive layer 3 of the thermal adhesive tape 1 needs to contain a peroxide that generates an acid due to decomposition. The

1 ... thermal adhesive tape, 2 ... release liner, 3 ... adhesive layer

Claims (5)

A thermal adhesive tape which is not provided with a substrate and which bonds an adherend by heat and pressure bonding,
A substrateless thermal adhesive tape comprising an adhesive layer comprising an acrylonitrile-butadiene rubber, a phenol resin, a peroxide which generates an acid due to decomposition, and a phenol resin crosslinking agent.   The substrateless thermal adhesive tape according to claim 1, further comprising a release liner provided on at least one surface side of the adhesive layer and releasable from the adhesive layer.   The substrateless thermal adhesive tape according to claim 1 or 2, wherein the peroxide has a half-life temperature of 130 ° C or more and 170 ° C or less.   4. The adhesive layer according to any one of claims 1 to 3, wherein the adhesive layer contains the peroxide in an amount of 0.5 parts by mass or more and 5 parts by mass or less, based on 100 parts by mass of the acrylonitrile-butadiene rubber. The substrateless thermal adhesive tape as described above. A method for producing a thermal adhesive tape in which an adherend is joined by heat pressing without providing a base material,
Preparing a release liner, and
An adhesive layer for applying an adhesive layer solution containing an acrylonitrile-butadiene rubber, a phenolic resin, a peroxide that generates an acid due to decomposition, and a phenolic resin crosslinking agent to form the adhesive layer Forming process,
A method for producing a substrateless thermal adhesive tape, comprising:

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