KR20230107892A - Heat-peel adhesive tape - Google Patents

Abstract

It can be preferably used in a heating process at a high temperature, and when heated at a higher temperature after use in the heating process, the adhesiveness of the adhesive layer is significantly reduced, and it can be easily peeled off without remaining glue on the adherend. In order to provide a heat-peelable adhesive tape having excellent followability to irregularities, a heat-peelable adhesive layer is provided on at least one side of a base material, and the base material has (a) a tensile strength at 100% elongation of 0.9 MPa or less; (b) The compressive stress at the time of 50% compression is 2.0 MPa or less, (c) The value of tanδ at the maximum temperature at the time of use of the adhesive tape of 100 ° C. or higher obtained by dynamic viscoelasticity measurement under the conditions of a frequency of 10 Hz is 0.80 or less, and the heat-peelable adhesive layer (2) is 6 parts by mass or more 50 parts by mass with respect to 100 parts by mass of the adhesive component that forms the heat-expandable globules whose foaming start temperature is the maximum temperature at the time of use + 15 ° C. or higher to form the heat-peelable adhesive layer It is set as a heat-peelable adhesive tape contained within the range of parts by mass or less.

Description

Heat-peel adhesive tape

The present invention relates to a heat-peelable adhesive tape.

In various manufacturing processes including manufacturing processes of electronic components and semiconductor components, heat-peelable adhesive tapes are heat-peelable adhesive tapes in which heat-expandable microspheres are contained in the adhesive layer constituting the adhesive tapes, and the adhesive force is reduced by heating and can be peeled off. A technique using an adhesive tape is known. BACKGROUND ART [0002] In recent years, types in which solder bumps and metal pins used for connection with circuit board wiring parts are formed on electrode parts of semiconductor elements are increasing. In order to improve followability to the surface of a semiconductor element having solder bumps or metal pins, Patent Literature 1 proposes using a porous substrate as a substrate. In Patent Literature 1, a heat-peelable double-sided adhesive sheet in which a heat-peelable adhesive layer A is formed on one surface of a porous substrate and an adhesive layer B is formed on the other surface, wherein the porous substrate has a density of 0.9 g/cm 3 or less and is tensile. It is characterized by an elastic modulus of 20 MPa or less, and it is described that a workpiece having a surface having a surface maximum unevenness difference of 10 μm or more can be processed.

Further, Patent Literature 2 discloses a heat-peelable pressure-sensitive adhesive sheet in which a heat-expandable pressure-sensitive adhesive layer containing heat-expandable microspheres is laminated on at least one surface of a substrate through a rubber-like organic elastic layer. This heat-peelable pressure-sensitive adhesive sheet is said to be excellent in conformability to uneven surfaces by making the rubber-like organic elastic layer and the heat-expandable pressure-sensitive adhesive layer have a specific thickness and thickness ratio. Due to such trackability, sufficient adhesive force is developed even when the surface to be adhered is rough, and even when used as an adhesive sheet for dicing of a semiconductor substrate having a rough surface such as encapsulating resin, scattering of chips is difficult to occur, and further, after processing is completed, It is said that it can be peeled off easily without applying stress to the adherend by heating.

Japanese Unexamined Patent Publication No. 2008-115272 Japanese Unexamined Patent Publication No. 2014-037539

In Patent Documents 1 and 2, it is disclosed that the temperature is 100 to 250°C as a heat treatment condition for peeling after processing. However, in recent semiconductor manufacturing processes, there are many cases in which heat treatment is performed in a state where the adhesive sheet is adhered, and a heat-peelable adhesive tape that can be easily peeled by further heating without peeling even at a temperature of 100 ° C. or higher has been developed. is being demanded

The present invention has been made in view of the above problems, and in the adhesive tape used in the heating process of electronic parts and semiconductor parts, it can be preferably used in the heating process at a high temperature, and further heating at a higher temperature after use in the heating process It is an object of the present invention to provide a heat-peelable pressure-sensitive adhesive tape having significantly reduced adhesiveness of an adhesive layer, which can be easily peeled off without remaining glue on an adherend, and which has excellent followability to unevenness of an adherend.

As a result of intensive studies to achieve the above object, the present inventors have found that a heat-peelable adhesive tape having a heat-peelable adhesive layer on a substrate and at least one surface side of the substrate,

of the above,

(a) the tensile strength at 100% elongation is 0.9 MPa or less;

(b) the compressive stress at 50% compression is 2.0 MPa or less;

(c) The value of tanδ at the maximum temperature at the time of use of the heat-peelable adhesive tape at 100 ° C. or higher obtained by dynamic viscoelasticity measurement under the condition of a frequency of 10 Hz is 0.80 or less,

The heat-peelable adhesive layer,

(d) contains thermally expandable globules whose foaming start temperature is equal to or greater than the maximum temperature at the time of use + 15° C. It was found that a heat-peelable adhesive tape characterized by being in the range of 6 parts by mass or more and 50 parts by mass or less was very effective for solving the above problems, and came to complete the present invention.

The heat-peelable adhesive tape of the present invention can be preferably used without peeling even in high-temperature processes in various manufacturing processes including manufacturing processes of electronic components and semiconductor components, and further heated at a higher temperature after use in the same process. By doing so, the adhesiveness is remarkably reduced, the adhesive can be easily peeled off without remaining glue, and the adherence to unevenness of the adherend is excellent.

1 is a schematic sectional view showing an example of the layer configuration of a heat-peelable pressure-sensitive adhesive tape according to the present invention.

In Patent Literatures 1 and 2, examples in which the peeling temperature of the adhesive sheet is 100 to 120°C are shown, but the operating temperature in that case is naturally lower than 100°C, and since it is not specifically described, it is considered room temperature (around 25°C). do. Therefore, use at high temperatures of 100 DEG C or higher and peeling at higher temperatures are not sufficiently disclosed. In terms of conformability to unevenness of the adherend, it is preferable that the base material is soft, but if the heat resistance is not sufficient, glue may remain during thermal peeling, or the base material may become too soft, making peeling itself difficult.

Therefore, in the present invention, a material having both flexibility and heat resistance is used as a base material, and it is not peeled off when used at a high temperature of 100 ° C. or higher, and is used for a heat-peelable adhesive layer so that it can be easily peeled off by heating at a higher temperature than the use temperature. It was found that the object of the present invention can be achieved by combining those containing a predetermined amount of thermally expandable globules that start to expand at a temperature higher than the temperature.

Hereinafter, the heat-peelable adhesive tape according to the present invention will be described in detail.

The layer configuration of the heat-peelable pressure-sensitive adhesive tape according to the present invention will be described using a schematic sectional view shown in FIG. 1 .

Fig. 1 (A) shows a laminate configuration of a base material (1) and a heat-peelable adhesive layer (2), which are the minimum layer configuration, and Fig. 1 (B) further shows a heat-peelable adhesive layer (2) of the base material (1). A structure in which the support layer 3 is laminated on the surface opposite to the surface on which this is formed is shown. 1 (C) shows an example in which an intermediate support layer 4 is formed on the surface of the base material 1 on which the heat-peelable adhesive layer 2 is formed, and here, the intermediate support layer ( Although it is an example in which 4) was added, you may add the intermediate|middle support layer 4 to the layer structure of FIG.1(A). 1 (D) shows the layer structure of a double-sided adhesive tape in which an adhesive layer is formed on both sides of a base material 1, a heat-peelable adhesive layer 2 is formed on one side, and a second adhesive layer is formed on the other side. The layer structure in which the layer (5) is formed is shown. The second adhesive layer 5 can be either a normal adhesive layer or a heat-peelable adhesive layer. When the second adhesive layer 5 is a heat-peelable adhesive layer, the heating temperature for peeling may be the same as or different from that of the heat-peelable adhesive layer 2.

A release film (not shown) can be formed on the adhesive face of the heat-peelable adhesive layer and the surface of the substrate without a support layer to prevent adhering of adjacent layers during winding as a tape. As the release film, one or both surfaces of a resin film such as a film made of polyester (for example, polyethylene terephthalate: PET) subjected to release treatment can be used.

Hereinafter, each layer of the heat-peelable pressure-sensitive adhesive tape according to the present invention will be described.

<Description>

The substrate of the heat-peelable adhesive tape according to the present invention satisfies the following conditions (a) to (c) at the same time.

(a) the tensile strength at 100% elongation is 0.9 MPa or less;

(b) the compressive stress at 50% compression is 2.0 MPa or less;

(c) The value of tanδ at the maximum temperature at the time of use of the heat-peelable adhesive tape at 100° C. or higher, obtained by measuring dynamic viscoelasticity under the condition of a frequency of 10 Hz, is 0.80 or less.

The tensile strength of (a) was obtained by pulling a test piece (thickness 800 μm, width 25 mm, length 100 mm) at a rate of 300 mm/min at a gripping distance of 30 mm in an environment of 23° C. and 50% RH, and the elongation rate The tensile strength at the time of 100% is measured. A commercially available tensile tester can be used for the measurement. Tensile strength is 0.9 MPa or less, and it is preferable that it is 0.8 MPa or less.

For the compressive stress in (b), a test piece (30 mm × 30 mm × 12 mm) is compressed at a rate of 10 mm/min in an environment of 23°C and 50% RH, and the compressive stress at 50% deformation is measured. . A commercially available compression tester can be used for the measurement. The compressive stress is 2.0 MPa or less, preferably 1.5 MPa or less.

The tanδ (loss tangent) of (c) was applied to a test piece (10 mm × 10 mm × 2 mm) using a dynamic viscoelasticity measuring device, while applying shear strain at a frequency of 10 Hz, at a heating rate of 10 ° C./min, - Storage modulus (G') and loss modulus (G") are measured in the range of 50°C to 250°C. Tanδ from G"/G' at the maximum temperature at the time of use of the heat-peelable adhesive tape of 100°C or higher. is obtained by finding Here, "the maximum temperature at the time of use of the heat-peelable adhesive tape of 100 ° C. or higher" means the maximum temperature at 100 ° C. or higher when the heat-peelable adhesive tape is actually used, and this maximum temperature is the heat-peelable adhesive layer It is set to a temperature 15 ° C. or more lower than the foaming initiation temperature of the thermally expandable globule included in the Therefore, even if the same base material is used, it means that the measurement temperature of tanδ changes according to the heat-peelable adhesive layer to be combined. The value of tanδ is 0.80 or less, preferably 0.70 or less.

As the material of the base material, any material can be used as long as the above conditions (a) to (c) are satisfied, but as the base resin (main component), any of acrylic resins, silicone resins, and urethane resins is preferable. From these resins, materials capable of satisfying the tensile strength and compressive stress defined by the conditions (a) and (b) above, and having heat resistance sufficient to reduce the value of tanδ under the above condition (c) to 0.80 or less can be obtained. You can choose.

As the acrylic resin, an acrylic resin composition containing mainly an alkyl (meth)acrylic acid ester as a monomer component and combining this with a copolymerizable vinyl monomer can be used to obtain an acrylic resin composition containing an acrylic copolymer resin.

Examples of the (meth)acrylic acid alkyl ester include those having 1 to 20 carbon atoms in the alkyl ester moiety, preferably 1 to 12 carbon atoms, and more preferably 1 to 8 carbon atoms. Specific examples of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, and tert-butyl (meth)acrylate. , (meth) isobutyl acrylate, (meth) hexyl acrylate, (meth) acrylate isohexyl, (meth) acrylate octyl, (meth) acrylate isooctyl, (meth) ethylhexyl acrylate, (meth) acrylate nonyl, (meth) Isononyl acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, dodecyl (meth)acrylate, isododecyl (meth)acrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, etc. can These may use 1 type, and may use 2 or more types together. (meth)acrylic acid alkyl ester is 50 mass % or more, preferably 60 mass % or more, more preferably 70 mass % or more, and it is optimal that it is 80 mass % or more in all monomers.

Examples of copolymerizable vinyl monomers include (meth)acrylic acid, carboxylic acid-containing (meth)acrylic monomers such as (meth)acrylic acid β-carboxyethyl, itaconic acid, crotonic acid, maleic acid and fumaric acid, and (meth)acrylic acid-2. -Hydroxyethyl, (meth)acrylic acid-2-hydroxypropyl, (meth)acrylic acid-2-hydroxybutyl, (meth)acrylic acid-4-hydroxybutyl, (meth)acrylic acid-2-hydroxyhexyl, ( Copolymerizable monomers containing hydroxyl groups, such as monoesters of meth)acrylic acid with polyethylene glycol or polypropylene glycol; N-alkyl-substituted (meth)acrylamides such as (meth)acrylamide and N-isopropyl (meth)acrylamide; , N,N-dialkyl substituted (meth)acrylamides such as N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, acryloylmorpholine, vinylpyridine, N-vinyl nitrogen-containing acrylic monomers such as pyrrolidone, aminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, and dimethylaminopropyl (meth)acrylate; vinyl monomers such as vinyl acetate; and the like. These may use 1 type, and may use 2 or more types together. It is preferable to contain acrylic acid especially, and it is preferable to contain 1-20 mass % of all monomers, and, as for acrylic acid, it is more preferable to contain 4.75-19 mass %.

The acrylic resin composition can be obtained by, for example, polymerizing (meth)acrylic acid alkyl ester and acrylic acid to prepare an acrylic syrup, and then further adding other monomers and additives of the acrylic syrup. A base material can be produced by applying this acrylic resin composition on a support having releasability and curing by UV curing or the like.

As additives to the resin composition, hollow particles such as resin balloons and glass balloons, resin particles such as urethane beads, epoxy-based, isocyanate-based, and polyfunctional acrylate-based crosslinking agents, fillers, colorants, antioxidants, ultraviolet absorbers, interfaces Known additives such as activators, polymerization initiators and chain transfer agents can be added.

What is necessary is just to select what satisfy|fills the said condition (a) - (c) also about a silicone type resin and a urethane type resin, combining raw materials and materials which can be used as a base material for tapes. In the case of a silicone-based resin, it is preferable to use a platinum-based catalyst that promotes the dehydration condensation of the siloxane compound in combination. In urethane-type resin, it is preferable to use together a crosslinking agent, such as an epoxy type and an isocyanate type.

Moreover, you may select what satisfy|fills the said conditions (a) - (c) as a base material from among what is marketed as a base material for tapes. In that case, a product manufactured as a porous body such as urethane foam may be used.

The thickness of the substrate is not particularly limited as long as it satisfies the conformability to unevenness in accordance with the purpose of use, but is preferably 30 μm or more, and more preferably 50 μm or more. Moreover, 2000 micrometers or less are preferable and, as for the upper limit of thickness, 1000 micrometers or less are more preferable.

<Heat-peelable adhesive layer>

The heat-peelable adhesive layer according to the present invention contains an adhesive and heat-expandable globules, and the content of the heat-expandable globules is in the range of 6 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the pressure-sensitive adhesive component forming the heat-peelable adhesive layer. am. The foaming start temperature of the heat-expandable pellets is a temperature equal to or higher than the maximum temperature at the time of use specified in the above condition (c) + 15°C.

Examples of the thermally expandable microspheres used in the present invention include microspheres in which a substance that is easily gasified and expanded by heating, such as isobutane, propane, or pentane, is encased in an elastic shell. . The shell is often formed of a heat-melting material or a material that is destroyed by thermal expansion. As the material forming the shell, for example, vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, polysulfone, etc. can be heard Thermally expandable globules can be produced by conventional methods such as coacervation and interfacial polymerization. The foaming initiation temperature can be controlled mainly by the thickness of the shell, and the foaming initiation temperature tends to increase as the thickness increases. For example, Matsumoto Microspheres (registered trademark) F and FN series having a shell film thickness of 2 to 15 μm and an average particle diameter of 5 to 50 μm are commercially available from Matsumoto Yuji Pharmaceutical Co., Ltd. and can be preferably used. The thermally expandable globules may be selected based on their foaming start temperature and foaming ratio.

As the pressure-sensitive adhesive component forming the heat-peelable pressure-sensitive adhesive layer, any pressure-sensitive adhesive component can be used as long as it has sufficient adhesive strength at the operating temperature and can be peeled off by heating at a higher temperature by foaming the heat-expandable pellets. Specifically, (meth)acrylic copolymers, silicone-based adhesives, polyester-based adhesives, and the like are exemplified. It is also preferable to select the resin of the same kind as the resin which comprises a base material especially from the point of adhesiveness with a base material.

As a (meth)acrylic-type copolymer, it can be used combining the vinyl-type monomer used for the base material. Especially, it is preferable to have as a main component at least one type of structural unit derived from a (meth)acrylic-acid alkylester, and to contain the structural unit derived from acrylic acid. Moreover, it is preferable to contain 2 mass % or more with respect to 100 mass % of all monomer units, and, as for the structural unit derived from acrylic acid, it is more preferable to contain 5 mass % or more. When the structural unit derived from acrylic acid is 2% by mass or more with respect to 100% by mass of all monomer units, even if the operating temperature is as high as 150°C, the conformability to level difference after heating is excellent. Moreover, it is also a preferable aspect to use in combination with the acrylic acid ester containing a hydroxyl group from the point which raises adhesive force.

The content of the heat-expandable globules is in the range of 6 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the pressure-sensitive adhesive component forming the heat-peelable adhesive layer, but is preferably 6 parts by mass or more and 40 parts by mass or less. If the content of the thermally expandable microspheres is less than 6 parts by mass, the thermal release properties due to foaming of the thermally expandable microspheres cannot be sufficiently exhibited. In addition, when the content of the heat-expandable pellets exceeds 50 parts by mass, the relative amount of the pressure-sensitive adhesive component decreases, and desired adhesive force cannot be obtained.

In addition, if the foaming start temperature of the thermally expandable pellets is less than 15° C. with respect to the maximum temperature during use specified in the above condition (c), peeling or thermal peeling properties decrease during heating and use, and after heating to the thermal peeling temperature, return to room temperature. When peeling, adhesive force does not fully fall, and peeling may become difficult.

A known additive can be added to the heat-peelable pressure-sensitive adhesive layer, in addition to the above-mentioned pressure-sensitive adhesive component and heat-expandable pellets, within a range that does not impair the effect of the present invention. Examples of additives include ultraviolet absorbers, antioxidants, colorants, and various fillers.

The thickness of the heat-peelable adhesive layer is larger than the particle size of the heat-expandable globules to be added, and may be within a range that does not impair the concavo-convex followability of the base material. For example, it may be selected from the range of 10 to 100 μm based on the thickness of the substrate or the particle size of the thermally expandable globules. The particle size of the thermally expandable globules may be set by estimating the maximum particle size from the average particle size (catalog value) in the case of a commercial product, or may be set by removing large particles by sieving or the like to set the size of the sieve opening.

<support layer>

In the heat-peelable pressure-sensitive adhesive tape according to the present invention, a resin film different from that of the base material 1 is placed on at least one side of the base material 1 as a support layer 3 or an intermediate portion as shown in FIGS. 1(B) and (C). It can be provided as the support layer 4. The substrate used in the present invention may have tackiness, and in some cases, sufficient strength may not be obtained when the thickness of the substrate is thin. Therefore, it is preferable to provide a resin film as the support layer 3 or the intermediate support layer 4.

As the resin contained in the resin film, those having lower tackiness than the substrate, having heat resistance, and excellent strength are preferable, and polyimide resins, fluorine resins, polyester resins, polyether ether ketone resins, polyphenylene sulfide resins, and It is preferably at least one selected from the group of polycycloolefin resins. Among them, polyimide resin and polyethylene terephthalate (PET) are preferred.

The thickness of the support layer 3 is preferably 20 μm or more, and more preferably 40 μm or more, from the viewpoint of imparting adequate strength. As an upper limit, what is necessary is just to set considering the thickness of a base material, or the thickness of the whole heat-peelable adhesive tape. The thickness of the intermediate support layer 4 is preferably 20 µm or less, and more preferably 15 µm or less, because the thicker the thickness, the higher the thickness of the substrate. The addition or subtraction is not particularly limited, but in terms of forming the intermediate support layer 4, it is preferably 1 μm or more, and more preferably 5 μm or more.

<double-sided adhesive tape>

As shown in Fig. 1 (D), the heat-peelable pressure-sensitive adhesive tape according to the present invention is a double-sided adhesive in which a second pressure-sensitive adhesive layer 5 is formed on the surface of the base material opposite to the surface on which the heat-peelable pressure-sensitive adhesive layer 2 is formed. You can do it with tape. At this time, with respect to the second adhesive layer 5, the heat-peelable adhesive layer 2 may be referred to as a first adhesive layer. The first adhesive layer is a heat-peelable adhesive layer according to the present invention, but the second adhesive layer may be a heat-peelable adhesive layer or a normal adhesive layer. When the second adhesive layer is a heat-peelable adhesive layer, it may be the same as or different from the heat-peelable adhesive layer of the first adhesive layer. In short, it is good also as a heat-peelable adhesive layer that thermally peels at a higher temperature or lower temperature than the first adhesive layer. By doing so, the temperature at which the member to be attached to each surface of the double-sided adhesive tape is gripped and removed can be set individually.

<How to use the heat-peelable adhesive tape>

The heat-peelable adhesive tape according to the present invention is used for a manufacturing process of a member having irregularities on its surface. A semiconductor substrate, an electronic component, etc. are mentioned as a member with unevenness|corrugation on the surface.

Particularly, an adherend targeted by the present invention is a member used in manufacturing that requires a temperature of 100°C or higher. For example, in processes such as solder reflow, a temperature of about 150 to 200°C may be applied. In the present invention, the maximum temperature reached in such a manufacturing process is taken as the maximum temperature (usage temperature) at the time of use of the heat-peelable pressure-sensitive adhesive tape.

Since the heat-expandable pellets included in the heat-peelable adhesive layer have a foaming start temperature in a temperature range 15° C. or more higher than the use temperature, the adhesive force can be maintained without foaming at the use temperature.

After that, in the case of peeling, by heating to a temperature equal to or higher than the foaming start temperature, the heat-expandable globules expand and foam to cause an action to separate the heat-peelable adhesive layer from the adherend. The heating temperature at this time is called the thermal peeling temperature, and as described above, it can be any higher than the foaming initiation temperature, but the time until the foaming is completed increases as the thermal peeling temperature is higher than the foaming initiation temperature. Therefore, the thermal peeling temperature is preferably a temperature higher than the foaming start temperature by 30°C or higher, and more preferably a temperature higher by 40°C or higher. In addition, the time at the time of thermal peeling can be appropriately set depending on the temperature difference between the thermal peeling temperature and the foaming start temperature, the shell material and shell thickness of the thermally expandable globules, and the type of encapsulated vapor.

In addition, when peeling, in order to avoid so-called glue residue, in which the residue of the heat-expandable pellets and the residue of the adhesive remain on the adherend, it is preferable to peel after cooling. The temperature at the time of peeling is a temperature lower than the operating temperature, preferably 100 ° C. or less, more preferably 50 ° C. or less, and may be peeled by cooling to room temperature (around 25 ° C.).

Example

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited only to these examples. In addition, "part" or "%" in Examples and Comparative Examples represents a value based on mass unless otherwise specified.

[Method of making base material]

・How to prepare acrylic syrup

The composition shown in Table 1 was put into a flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen gas inlet, and an ultraviolet irradiation device (manufactured by Panasonic Co., Ltd.: trade name "Aicure UP50") was used in a nitrogen atmosphere, and the irradiation intensity was 800 to 1,200 An acrylic syrup was obtained by photopolymerizing by irradiating ultraviolet rays of mW/cm 2 (manufactured by I-Tech System: measured using photometer UVM-100) for 8 to 12 minutes.

･Production of acrylic substrate

To each of the obtained syrups 1 to 4, materials were added and mixed uniformly with the composition shown in Table 2 to obtain a base composition.

A PET release film having a thickness of 50 μm (manufactured by Fujimori Kogyo Co., Ltd., trade name “Film Viner (registered trademark) KF#50”) coated with a base composition on one side subjected to silicone release treatment, and coated with a release-treated surface, PET release treated in the same way The release-treated side of the film was placed on the substrate composition and sandwiched between two PET release films was produced. A fluorescent lamp (FL20S W manufactured by Toshiba Corporation) having an irradiation intensity of 3.0 to 5.0 mW/cm 2 was irradiated from both sides for 30 seconds to 2 minutes depending on the coating thickness to cure the base composition and obtain an acrylic base material. The thickness of the acrylic substrate was adjusted to be 50 μm to 800 μm.

Details of the materials in Table 2 are as follows:

・Resin balloon: Manufactured by Matsumoto Yuji Pharmaceutical Co., Ltd. Trade name “F-80DE”

・Glass balloon: manufactured by Potters Balotini, brand name “34P30T”

・Urethane beads: manufactured by Negami Kogyo Co., Ltd. Trade name “Art Pearl P-800T”

・α-Hydroxyacetophenone: IGM Resins, trade name "Omnirad 1173"

[Evaluation of physical properties of substrate]

Tensile strength, compressive stress, and tan δ of the obtained base material were measured by the following methods.

･Tensile strength of substrate

A substrate having a thickness of 800 μm, a width of 25 mm, and a length of 100 mm was tested using a tensile tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.: Strograph V-1C) at 23° C., 50% RH, gripping distance 30 mm, and test speed 300 mm. /min, and the tensile strength at 100% elongation was measured.

･Compressive stress of substrate

Substrates measuring 30 mm in width and length were laminated to form a laminate having a thickness of 12 mm. This laminate was compressed using a compression tester (manufactured by Shimadzu Corporation: AG-50 kNX Plus) under conditions of 23°C, 50% RH, and a test speed of 10 mm/min, and the compressive stress at 50% deformation was measured. measured.

・Tanδ of substrate

Substrates 10 mm square were laminated to form a laminate having a thickness of 2 mm. This laminate was subjected to shear strain at a frequency of 10 Hz using a dynamic viscoelasticity measuring device (ARES-G2 manufactured by TA Instruments) at a heating rate of 10 °C/min in the range of -50 °C to 250 °C. The storage modulus (G') and the loss modulus (G") were measured. From the storage modulus (G') and the loss modulus (G"), the loss tangent tanδ at each temperature was calculated by the following formula.

tanδ = loss modulus (G")/storage modulus (G')

The above result is shown in Table 3. In addition, commercially available silicone substrates and urethane substrates were evaluated in the same manner.

The description names in Table 3 are as follows.

Si: Silicon substrate, trade name "Unicorn UT-30", manufactured by Kotech

PU: Urethane base material, trade name "PureCell (registered trademark) UC150PR", manufactured by Inoac Corporation

In the above, the colored parts represent the parts that do not satisfy the conditions related to the present invention, and the same is true in the table below. Substrate AS9 does not satisfy conditions (a) and (b) related to the present invention, and substrate AS10 is a substrate that does not satisfy condition (c) related to the present invention. The remaining AS1 to AS8, Si, and PU substrates are substrates that can respond to any use temperature of 100 to 180°C.

[Method of manufacturing heat-peelable adhesive layer]

・Base polymer (acrylic copolymer) preparation method

Acrylic copolymers Ac1 to Ac4 having the composition shown in Table 4 were polymerized.

The compounding ratio of each component in Table 4 shows the ratio when the total is 100 parts. For reference, the theoretical Tg and weight average molecular weight (Mw) of each acrylic copolymer were listed together in Table 3. Theoretical Tg is a value calculated by the formula of FOX, and can be adjusted by appropriately selecting the composition of the acrylic monomer. In addition, this weight average molecular weight (Mw) is a value measured by the GPC method, and the weight average molecular weight of standard polystyrene conversion of an acrylic copolymer was measured on the following measuring apparatus and conditions.

Device: LC-2000 series (manufactured by Japan Spectroscopy Co., Ltd.)

Column: ShodexKF-806 M × 2, ShodexKF-802 × 1

・Eluent: tetrahydrofuran (THF)

·Flow rate: 10 mL/min

·Column temperature: 40 ℃

·Injection amount: 100 μL

Detector: sum of refractive indices (RI)

· Measurement sample: An acrylic polymer was dissolved in THF to prepare a solution having an acrylic polymer concentration of 0.5%, and dust was removed by filtration with a filter.

The weight average molecular weight (Mw) is determined by the type and amount of the polymerization initiator (for example, 0.1 part of lauryl peroxide per 100 parts of the acrylic monomer) and the type and amount of the chain transfer agent (for example, in the polymerization of the acrylic copolymer). For example, 0.1 part of n-dodecanethiol with respect to 100 parts of the acrylic monomer), polymerization initiation concentration (for example, 50%), etc. can be adjusted appropriately.

[Method for preparing pressure-sensitive adhesive composition]

With respect to 100 parts of solid content of each adhesive, materials were added and mixed uniformly according to the composition shown in Table 5 below to obtain a heat-peelable adhesive composition.

In Table 5, the materials used are as follows:

・Silicone adhesive: manufactured by Shin-Etsu Chemical Co., Ltd., product name “KR-3700” and “X-40-3306” mixture (mass ratio 80/20)

・Polyester adhesive: manufactured by Mitsubishi Chemical Co., Ltd., trade name "NP-110S50"

FN-190SSD: Trade name "Matsumoto Microsphere (registered trademark) FN-190SSD", manufactured by Matsumoto Yuji Pharmaceutical Co., Ltd., foaming start temperature 171 ° C.

・F-260D: Product name "Matsumoto Microsphere (registered trademark) F-260D", manufactured by Matsumoto Yuji Pharmaceutical Co., Ltd., foaming start temperature 198 ° C.

FN-100MD: Trade name "Matsumoto Microsphere (registered trademark) FN-100MD", manufactured by Matsumoto Yuji Pharmaceutical Co., Ltd., foaming start temperature 119 ° C.

・F-50D: Product name "Matsumoto Microsphere (registered trademark) F-50D", manufactured by Matsumoto Yuji Pharmaceutical Co., Ltd., foaming start temperature 112 ° C.

E-5CM: Trade name, manufactured by Soken Chemical Co., Ltd., epoxy-based crosslinking agent, solid content 5%

L-45E: trade name, manufactured by Tosoh Corporation, isocyanate-based crosslinking agent, solid content 45%

CAT-PL-50T: Product name, manufactured by Shin-Etsu Chemical Co., Ltd., platinum-based catalyst

Irganox 1010: Trade name, manufactured by BASF, hindered phenolic antioxidant

Examples 1 to 22, Comparative Examples 1 to 4

[How to make adhesive tape]

The adhesive composition obtained above was coated on a PET release film having a thickness of 50 μm (manufactured by Fujimori Kogyo Co., Ltd., trade name “Film Viner (registered trademark) KF#50”) subjected to silicone release treatment so that the adhesive layer had a thickness of 50 μm. . Next, it was placed in a drying machine (PHH-201 manufactured by Espec Co., Ltd.), and a crosslinking reaction was carried out while drying the diluting solvent at 50 to 110°C to form a heat-expandable adhesive layer. Peel off the PET release film on both sides of the base material, transfer the heat-expandable adhesive layer to one side of the base material, and attach a 50 μm thick PET film (manufactured by Toray Corporation, trade name “Lumiror #50-S10”) to the other side, 40 It cured at degreeC for 3 days and obtained the adhesive tape. The heat-peelable adhesive tape of the layer structure shown in FIG. 1(B) was produced with the combination of the base material and adhesive shown in Table 6. In addition, the physical properties of the base material measured by the following method, the foaming start temperature of the thermally expandable pellets, the test temperature based thereon (the temperature at which the adhesive tape is used), the thermal peeling temperature, and the value of tanδ of the base material at the test temperature are shown in Table 6. shown along with

[Evaluation of physical properties of adhesive layer]

・Measurement method of the foaming initiation temperature of thermally expandable globules

The foaming start temperature of the heat-expandable globules can be obtained by using a thermal analyzer TMA (TMA7100 manufactured by Hitachi High-Tech Science Co., Ltd.). The foaming start temperature of the thermally expandable pellets was measured by inserting the thermally expandable pellets into a 5 mmφ aluminum pan, closing the inner cover, and analyzing in the compression mode (L assembly control, heating rate: 10°C/min). It was set as the temperature at which the displacement in the vertical direction of .

In Table 6, the step conformability was evaluated for the example in which the test temperature was 150°C.

·Step followability

A polyimide tape (manufactured by Teraoka Manufacturing Co., Ltd., product name "No. 6544") having a thickness of 90 µm and a size of 5 mm x 30 mm was affixed to the glass plate to prepare a stepped glass having pseudo-steps for testing. The heat-expandable adhesive layer side of the 20 mm square adhesive tape was placed on the stepped glass, it was reciprocated once at 300 mm/min with a 5 kg rubber roller, and it was affixed to prepare a test piece. Using a microscope (manufactured by Keyence Corporation: VHX-6000), the cell width generated around the step was measured at three points at intervals of 5 mm, and the average value was calculated.

The test piece was placed in a dryer, and after heating at a test temperature of 150°C for 30 minutes, the cell width was similarly calculated.

The followability of step differences was evaluated according to the following criteria.

A: cell width less than 1 mm

B: Cell width 1 mm or more and less than 5 mm

C: Bubbles were connected or the adhesive tape peeled off from the test piece.

In Comparative Example 1, since the base material of AS9 that does not satisfy the above conditions (a) and (b) of the present invention was used, it was confirmed that the flexibility was low and the level conformability was inferior. As shown in Examples 2 to 4, it is understood that there is almost no influence of the substrate thickness.

heat resistance

The effect of tan δ on the substrate under the above condition (c) was evaluated. Specifically, in the example of an acrylic substrate having a substrate thickness of 200 μm, an adhesive tape was cut into 20 mm in width and length, and the thickness (manufactured by Peacock: Dial Thickness Gauge G-6), dimensions (manufactured by Keyence Corporation: VHX- 6000) was measured. A float glass plate (R 3202) with a weight of 20 g (2.8 mm in thickness, 50 mm × 60 mm) is placed on an aluminum plate (A1050P) with a thickness of 1.0 mm and a thickness of 50 mm × 125 mm and an adhesive tape measuring 20 mm in width and length is placed. put on top After placing this in a dryer (PHH-201 manufactured by Espec Corporation) and heating at the test temperature shown in Table 5 for 30 minutes, the thickness and size of the adhesive tape were measured.

The thickness was measured at the center of the tape, and the dimensions were measured at 3 points each at 5 mm intervals in the width direction and length direction of the tape, for a total of 6 points, and an average value was calculated.

Heat resistance was evaluated according to the following criteria.

A: Thickness reduction before and after heating is less than 15%, or dimensional change is less than 0.5 mm

C: Thickness reduction before and after heating of 15% or more, or dimensional change of 0.5 mm or more

A result is shown in Table 8.

As can be seen from the above Table 8, when the tan δ at the processing temperature of the substrate was 0.80 or less, deformation during processing could be suppressed. In Comparative Example 2 in which tan δ exceeded 0.80, the dimensional change was large. In addition, also in Example 11 using a silicone base material and Example 12 using a urethane base material, tan δ was 0.80 or less, and deformation during processing was suppressed.

Next, adhesion and heat release properties were evaluated.

·Initial adhesion

An adhesive tape having a width of 10 mm and a length of 100 mm was bonded to an aluminum plate (A1050P) having a thickness of 1.0 mm and a size of 50 mm x 125 mm. After making it press|bond by making it crimp|bond by 1 reciprocating at a speed of 300 mm/min with a 5-kg roller, it was left to stand for 20 to 40 minutes at 23 degreeC and 50 %RH. Using a tensile tester, the peel force of the adhesive layer was measured at 23°C, 50% RH, a test speed of 300 mm/min, and a peel angle of 90°, and was taken as the initial adhesive force.

Adhesion after heating

In the same way as in the measurement of the initial adhesive strength, the adhesive tape was bonded and crimped, and then put in a dryer and heated at the test temperature shown in Table 6 for 30 minutes. After taking it out of the dryer and leaving it at 23 ° C. and 50% RH for 20 to 40 minutes, the peel force of the tape was measured using a tensile tester at 23 ° C. and 50% RH at a test speed of 300 mm / min and a peel angle of 90 °. .

·Heat peelability

After heating, it was heated at the same test temperature as the adhesive strength, taken out of the dryer, left at 23 ° C. and 50% RH for 20 to 40 minutes, and then put in a dryer set at the heat peeling temperature shown in Table 6 and heated for 5 minutes. It was taken out from the drying machine and left at 23°C and 50% RH for 20 to 40 minutes. At that time, what was naturally exfoliated was designated as "A". For those that did not spontaneously peel, the peel force was evaluated as the same as the above adhesive force, and a peel force of less than 1.0 N/10 mm was evaluated as "B", and a peel force of 1.0 N/10 mm or more was evaluated as "C". A result is shown in Table 9.

Example 23

A PET release film having a thickness of 50 μm (manufactured by Fujimori Industries, product name “Film Viner (registered trademark) KF#50 ”), an adhesive tape was obtained in the same manner as in Example 1 except for changing to The layer configuration except for the PET release film is shown in Fig. 1(A).

In addition, at the time of step followability test, the PET release film was peeled off and heated, and at the time of measuring the adhesive strength, the PET release film was peeled off and a 50 μm PET film (manufactured by Toray Corporation, product name “Lumiror #50-S10”) was attached. was measured.

Example 24

An adhesive tape was obtained in the same manner as in Example 1 except that the PET film on the opposite side of the heat-expandable adhesive layer was changed to a PI film having a thickness of 50 μm (manufactured by Toray DuPont, product name “Kapton 100H”).

Example 25

The adhesive composition AD1 was applied onto an intermediate support layer made of a 12 μm-thick PET film (manufactured by Toray Industries, product name “Lumiror #12-S10”) so that the thickness of the adhesive layer was 50 μm. Next, it was put in a dryer and while drying the diluting solvent at 50 to 110°C, a crosslinking reaction was carried out to form a heat-expandable adhesive layer. The PET release film on one side of the acrylic substrate 1 was peeled off, and the substrate was affixed to the PET film side of the PET film coated with the heat-expandable adhesive layer. The PET film on the other side of the substrate was peeled off, a PET film having a thickness of 50 μm was attached, and cured at 40° C. for 3 days to obtain an adhesive tape having a layer structure shown in FIG. 1(C).

Example 26

The pressure-sensitive adhesive composition AD1 was coated on a PET release film (manufactured by Fujimori Kogyo, product name “Film Viner (registered trademark) KF#50”) having a thickness of 50 μm subjected to silicone release treatment so that the adhesive layer had a thickness of 50 μm. Then, while putting in a dryer and drying the diluting solvent at 50 to 110°C, a cross-linking reaction was carried out to prepare two films in which a heat-expandable adhesive layer was formed. The PET release film on one side of the substrate was peeled off, and the first heat-expandable adhesive layer was transferred to form a first adhesive layer. On the 1st adhesive layer, the said PET release film was bonded together from the release treatment surface side. Further, the PET release film on the other side of the substrate was peeled off, the second heat-expandable adhesive layer was transferred to form a second adhesive layer, and the PET release film was bonded on the second adhesive layer from the side of the release treatment surface. Then, it cured at 40 degreeC for 3 days and obtained the adhesive tape.

In addition, during the step followability test, the PET release film on the opposite side of the adhesive side is also peeled off and heated, and when measuring the adhesive force, the PET release film on the opposite side of the adhesive side is peeled off to obtain a 50 μm PET film (manufactured by Toray Corporation). Product name "Lumiror #50-S10") was affixed and measured.

Table 10 shows the results of Examples 23 to 26 above.

As can be seen from the above Table 10, even if the tape structure is different, step followability and heat release properties can be expressed. In addition, heat release properties can be imparted to both surfaces by providing a thermally expandable pressure-sensitive adhesive layer on both surfaces.

1: Substrate
2: heat release adhesive layer
3: support layer
4: middle support layer
5: 2nd adhesive layer

Claims (8)

A heat-peelable adhesive tape comprising a substrate and a heat-peelable adhesive layer on at least one side of the substrate,
of the above,
(a) the tensile strength at 100% elongation is 0.9 MPa or less;
(b) the compressive stress at 50% compression is 2.0 MPa or less;
(c) The value of tanδ at the maximum temperature at the time of use of the heat-peelable adhesive tape at 100 ° C. or higher obtained by dynamic viscoelasticity measurement under the condition of a frequency of 10 Hz is 0.80 or less,
The heat-peelable adhesive layer,
(d) including thermally expandable pellets whose foaming start temperature is the maximum temperature during use + 15°C or higher, and the content of the thermally expandable pellets is 6 parts by mass or more relative to 100 parts by mass of the pressure-sensitive adhesive component forming the heat-peelable adhesive layer A heat-peelable adhesive tape characterized in that it is in the range of 50 parts by mass or less. According to claim 1,
The heat-peelable adhesive tape wherein the base material is a resin base material containing at least one or more resins selected from the group consisting of acrylic resins, silicone resins, and urethane resins as a main component. According to claim 1,
The heat-peelable adhesive tape wherein the pressure-sensitive adhesive component contains a (meth)acrylic copolymer as a main component. According to claim 1,
The (meth)acrylic copolymer includes a structural unit derived from acrylic acid, and the content of the structural unit derived from acrylic acid is based on 100% by mass of all monomer units constituting the (meth)acrylic copolymer, 2% by mass or more, a heat-peelable adhesive tape. According to claim 1,
The heat-peelable adhesive tape which equips at least one surface side of the said base material with the resin film different from the said base material as a support layer. According to claim 5,
A heat-peelable adhesive tape wherein the resin contained in the resin film is at least one selected from the group consisting of polyimide resins, fluorine resins, polyester resins, polyether ether ketone resins, polyphenylene sulfide resins, and polycycloolefin resins. . According to claim 1,
The heat-peelable adhesive layer formed on one surface side of the base material is a first adhesive layer, and a second adhesive layer is provided on the other surface side different from the one surface side of the base material, and the second adhesive layer is A heat-peelable adhesive tape, which is an adhesive layer having the same or different structure as the first adhesive layer. According to any one of claims 1 to 7,
A heat-peelable adhesive tape characterized in that it is used for a manufacturing process of a member having irregularities on its surface.

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