WO2023136171A1

WO2023136171A1 - Single-sided adhesive tape

Info

Publication number: WO2023136171A1
Application number: PCT/JP2022/048577
Authority: WO
Inventors: 徳之内田
Original assignee: 積水化学工業株式会社
Priority date: 2022-01-13
Filing date: 2022-12-28
Publication date: 2023-07-20
Also published as: TW202334353A; CN117813359A

Abstract

The purpose of the present invention is to provide a single-sided adhesive tape that does not tend to wrinkle even when affixed to a thin adherend and that has exceptional resistance to strong alkaline solutions. The present invention is a single-sided adhesive tape having a base material and a heat-sensitive adhesive layer laminated on one side of the base material, wherein the base material has a metal layer at least on the surface opposite the heat-sensitive adhesive layer, and the heat-sensitive adhesive layer has a static friction coefficient against SUS of 5 or less.

Description

single sided adhesive tape

The present invention relates to single-sided adhesive tapes.

2. Description of the Related Art Conventionally, adhesives and adhesive tapes have been widely used to fix components in electronic devices. Adhesive tape is also used as a processing material in the manufacturing process of electronic devices. used. In addition to high adhesiveness, these adhesives and adhesive tapes are required to have functions such as heat resistance, thermal conductivity, and impact resistance depending on the environment in which they are used (for example, Patent Documents 1 to 3 ).

JP 2015-052050 A JP 2015-021067 A JP 2015-120876 A

On the other hand, substrates such as printed wiring boards used in electronic devices are manufactured by forming a circuit on a copper foil portion of a copper clad laminate (CCL) in which a copper foil and a resin layer are laminated.
In recent years, substrates such as printed wiring boards have become thinner. There is a problem that the edges of the copper clad laminate are damaged during the process.

In order to prevent damage to the ends of the copper-clad laminate, the present inventors have studied protecting the ends of the copper-clad laminate by attaching an adhesive tape.
However, since the copper-clad laminate is thin as described above, the copper-clad laminate bends or warps when the adhesive tape is attached to the edge of the copper-clad laminate. It has been found that the adhesive tape comes into contact with the adhesive tape and sticks to it, causing the adhesive tape to wrinkle. Further, in the etching process, the desmear process, etc., which are performed in the substrate manufacturing process, a strong alkaline solution is used as the processing liquid. For this reason, when exposed to a strong alkaline solution, the adhesive tape peels off, resulting in insufficient protection of the edges of the copper-clad laminate and corrosion of the copper on the surface of the copper-clad laminate.

SUMMARY OF THE INVENTION An object of the present invention is to provide a single-sided pressure-sensitive adhesive tape that does not wrinkle easily even when applied to a thin adherend and has excellent resistance to strong alkaline solutions.

The present disclosure 1 is a single-sided adhesive tape having a substrate and a heat-sensitive adhesive layer laminated on one surface of the substrate, wherein the substrate is at least on the side opposite to the heat-sensitive adhesive layer. A single-sided adhesive tape having a metal layer on the surface and the heat-sensitive adhesive layer having a static friction coefficient of 5 or less against SUS.
The present disclosure 2 is the single-sided adhesive tape of the present disclosure 1, wherein the metal layer is made of copper.
Present Disclosure 3 is the single-sided pressure-sensitive adhesive tape according to Present Disclosure 1 or 2, wherein the substrate is a metal substrate.
Present Disclosure 4 is the single-sided pressure-sensitive adhesive tape according to Present Disclosure 3, wherein the metal substrate is a copper foil.
This disclosure 5 is the single-sided adhesive tape of this

disclosure

1, 2, 3 or 4, further comprising a pressure sensitive adhesive layer between said substrate and said heat sensitive adhesive layer.
The

present disclosure

1, 2, 3, 4 or 5, wherein the heat-sensitive adhesive layer has a loss tangent peak temperature of 40 ° C. or higher measured at a measurement frequency of 1 Hz using a dynamic viscoelasticity measuring device. is a single-sided adhesive tape.
According to the present disclosure 7, the heat-sensitive adhesive layer has a storage modulus G' of 5 MPa or more at 23°C and a storage modulus G' of 0.2 MPa or less at 100°C. 5 or 6 single-sided adhesive tape.
The present disclosure 8 is the single-sided adhesive tape according to the

present disclosure

1, 2, 3, 4, 5, 6 or 7, wherein the heat-sensitive adhesive layer has a gel fraction of 50% by weight or more.
The present disclosure 9 is the single-sided adhesive tape of the

present disclosure

1, 2, 3, 4, 5, 6, 7, or 8, wherein the heat-sensitive adhesive layer has a surface roughness Ra of 0.01 μm or more and 0.8 μm or less. is.
The present disclosure 10 is the single-sided adhesive tape according to the

present disclosure

1, 2, 3, 4, 5, 6, 7, 8 or 9, wherein the heat-sensitive adhesive layer contains an acrylic polymer.
Present Disclosure 11 is the single-sided adhesive tape of Present Disclosure 10, wherein the heat-sensitive adhesive layer further contains a tackifying resin.
The present disclosure 12 is the single-sided adhesive tape of the present disclosure 11, wherein the tackifying resin has a softening point of 100° C. or higher.
Present Disclosure 13 is the single-sided pressure-sensitive adhesive tape according to Present Disclosure 11 or 12, wherein the tackifying resin has a hydroxyl value of 25 mgKOH/g or more.
Present Disclosure 14 is the single-sided pressure-sensitive adhesive tape according to Present Disclosure 11, 12 or 13, wherein the content of the tackifier resin is 5 parts by weight or more and 50 parts by weight or less with respect to 100 parts by weight of the acrylic polymer.
The present disclosure 15 is the single-sided adhesive tape according to the present disclosure 10, 11, 12, 13 or 14, wherein the heat-sensitive adhesive layer contains an epoxy-based cross-linking agent.
The present disclosure 16 is the single-sided adhesive tape of the present disclosure 5, wherein the pressure-sensitive adhesive layer has a gel fraction of 50% by weight or more.
The present disclosure 17 is the single-sided adhesive tape of the present disclosure 5, wherein the pressure-sensitive adhesive layer contains an epoxy-based cross-linking agent.
The present disclosure 18 is a single-sided adhesive tape having a base material and a heat-sensitive adhesive layer laminated on one side of the base material, wherein the base material is at least on the side opposite to the heat-sensitive adhesive layer. It has a metal layer on the surface, and the heat-sensitive adhesive layer contains an acrylic polymer and a tackifying resin, and the tackifying resin has a softening point of 100° C. or higher and a hydroxyl value of 25 mgKOH/ g or more, the content of the tackifying resin with respect to 100 parts by weight of the acrylic polymer is 5 parts by weight or more and 50 parts by weight or less, and the heat-sensitive adhesive layer has a coefficient of static friction against SUS of 5 or less. , is a single-sided adhesive tape.
The present disclosure 19 is an etching process, a desmear process, or an electroless plating process, the present disclosures 1 and 2, which are used to protect the edges of the metal-clad laminate by attaching them to the edges of the metal-clad laminate. , 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 or 18 single-sided adhesive tape.
The present disclosure 20 is a single-sided adhesive tape having a metal layer on one side and a heat-sensitive adhesive layer on the other side, wherein the heat-sensitive adhesive layer has a coefficient of static friction against SUS of 5 or less. It is a single-sided adhesive tape.
The present disclosure 21 is the single-sided adhesive tape of the present disclosure 21, wherein the metal layer is made of copper.
Disclosure 22 is the single-sided adhesive tape of Disclosures 20 or 21, further comprising a pressure sensitive adhesive layer between said substrate and said heat sensitive adhesive layer.
The present disclosure 23 is the single-sided adhesive tape of the present disclosure 20, 21 or 22, wherein the heat-sensitive adhesive layer has a loss tangent peak temperature of 40 ° C. or higher measured at a measurement frequency of 1 Hz using a dynamic viscoelasticity measuring device. is.
24 of the present disclosure 20, 21, 22, or 23, wherein the heat-sensitive adhesive layer has a storage elastic modulus G' of 5 MPa or more at 23°C and a storage elastic modulus G' of 0.2 MPa or less at 100°C. It is a single-sided adhesive tape.
The present disclosure 25 is the single-sided adhesive tape according to the present disclosure 20, 21, 22, 23 or 24, wherein the heat-sensitive adhesive layer has a gel fraction of 50% by weight or more.
26 of the present disclosure is the single-sided adhesive tape according to 20, 21, 22, 23, 24 or 25, wherein the heat-sensitive adhesive layer has a surface roughness Ra of 0.01 μm or more and 0.8 μm or less.
The present disclosure 27 is the single-sided adhesive tape of the present disclosure 20, 21, 22, 23, 24, 25 or 26, wherein the heat-sensitive adhesive layer contains an acrylic polymer.
This disclosure 28 is the single-sided adhesive tape of this disclosure 27, wherein said thermal adhesive layer further contains a tackifying resin.
This disclosure 29 is the single-sided adhesive tape of this disclosure 28, wherein the tackifying resin has a softening point of 100° C. or higher.
This disclosure 30 is the single-sided adhesive tape of this disclosure 28 or 29, wherein the tackifying resin has a hydroxyl value of 25 mgKOH/g or more.
Present Disclosure 31 is the single-sided adhesive tape according to Present Disclosures 28, 29, or 30, wherein the content of said tackifying resin relative to 100 parts by weight of said acrylic polymer is 5 parts by weight or more and 50 parts by weight or less.
32 of the present disclosure is the single-sided adhesive tape according to 27, 28, 29, 30 or 31 of the present disclosure, wherein the heat-sensitive adhesive layer contains an epoxy-based cross-linking agent.
This disclosure 33 is the single-sided adhesive tape of this disclosure 22, wherein the pressure-sensitive adhesive layer has a gel fraction of 50% by weight or more.
This disclosure 34 is the single-sided adhesive tape of this disclosure 22, wherein the pressure-sensitive adhesive layer contains an epoxy-based cross-linking agent.
The present disclosure 35 is used to protect the edges of the metal-clad laminate by attaching to the edges of the metal-clad laminate in the etching process, the desmear process, or the electroless plating process. , 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33 or 34.
The present invention will be described in detail below.

The present inventors have found that in a single-sided adhesive tape having a substrate and a heat-sensitive adhesive layer laminated on one side of the substrate, the substrate is placed on at least the surface opposite to the heat-sensitive adhesive layer, It has been considered to have a metal layer and to adjust the coefficient of static friction of the heat-sensitive adhesive layer against SUS to a certain value or less. The present inventors have found that such a single-sided pressure-sensitive adhesive tape is less likely to wrinkle when attached to a thin adherend and has excellent resistance to strong alkaline solutions, and has developed the present invention. I came to complete it.

In one aspect of the present invention, the single-sided adhesive tape has a substrate and a heat-sensitive adhesive layer laminated on one side of the substrate. The base material refers to the entire portion of the single-sided pressure-sensitive adhesive tape excluding the pressure-sensitive adhesive layer, and is a member that supports the pressure-sensitive adhesive layer. The adhesive layer includes the heat-sensitive adhesive layer positioned on the outermost surface of the single-sided adhesive tape, and another adhesive layer (for example, a pressure-sensitive adhesive layer) having a composition different from that of the heat-sensitive adhesive layer. may contain. That is, "the heat-sensitive adhesive layer laminated on one side of the base material" means that the heat-sensitive adhesive layer is disposed on one side of the base material, and the base material and the heat-sensitive adhesive layer are directly attached to each other. Or means that it is indirectly bonded, specifically, in the single-sided adhesive tape, the base material and the heat-sensitive adhesive layer are in direct contact, and It includes the case of having the above-mentioned other pressure-sensitive adhesive layer between the substrate and the above-mentioned substrate. Further, the heat-sensitive adhesive layer is a layer containing an adhesive that exhibits almost no adhesiveness at room temperature (23° C.) and exhibits adhesiveness when heated to a temperature equal to or higher than the glass transition point of the adhesive layer. The pressure-sensitive adhesive layer is a layer containing an adhesive that exhibits adhesiveness at room temperature (23°C).

The substrate has a metal layer at least on the surface opposite to the heat-sensitive adhesive layer. That is, in the single-sided adhesive tape of the present invention, one outermost surface is the metal layer forming the base material, and the other outermost surface is the heat-sensitive adhesive layer.
By disposing the metal layer on at least the surface of the base material, the metal layer is exposed on the outermost surface when the single-sided adhesive tape is attached to the edge of the metal-clad laminate. . This makes it difficult for the single-sided adhesive tape to come off even when exposed to a strong alkaline solution. Further, when a metal plating treatment such as electroless plating is performed, the metal plating layer deposited on the surface of the metal layer is difficult to separate from the metal layer. Therefore, even if the metal-clad laminate is plated with a single-sided adhesive tape, it is possible to prevent the metal-plated layer from peeling off from the single-sided adhesive tape in a later step. .

The metal forming the metal layer is not particularly limited, and examples thereof include copper, aluminum, nickel, and titanium. Moreover, alloys, such as stainless steel and Monel, are mentioned as a metal which comprises the said metal layer. Above all, it is preferable that the metal layer is made of copper, because the restoring force after folding is small and the single-sided pressure-sensitive adhesive tape can be easily handled because it is hard to break.

The substrate is not particularly limited as long as it has the metal layer on at least the surface opposite to the heat-sensitive adhesive layer, and may be composed of a single layer or multiple layers. may be
When the base material consists of a single layer, the base material is composed only of the metal layer. Below, the said base material comprised only by the said metal layer is also called a metal base material. In addition, the above metal base refers to all bases composed only of metal layers, and includes not only bases composed of a single metal layer but also bases composed of a plurality of metal layers.
When the substrate is composed of a plurality of layers, the layer constituting the surface opposite to the heat-sensitive adhesive layer is the metal layer, and other layers are not limited.
As the base material, for example, the base material itself may be a metal base material, or a laminated base material having a resin base material and the metal layer laminated on the surface of the resin base material, good too.
Among them, since the base material is the metal base material, the single-sided adhesive tape is folded back (bent) so as to extend from the front surface to the back surface of the metal-clad laminate and is attached to the edge of the metal-clad laminate. Even in such a case, since the metal base retains its shape, it is possible to suppress the restoring force due to the bending of the metal base. As a result, gaps are less likely to occur between the ends of the metal-clad laminate and the heat-sensitive adhesive layer, and peeling is less likely to occur.

The metal constituting the metal substrate is not particularly limited, and includes the metals constituting the metal layer as described above. Above all, it is preferable that the metal substrate is a copper foil, since the restoring force after folding is small and the single-sided pressure-sensitive adhesive tape can be easily handled because it is hard to break.

The resin substrate is not particularly limited. A resin film and a polyurethane-based resin film can be mentioned. Examples of the resin substrate include polyolefin foam sheets such as polyethylene foam sheets and polypropylene foam sheets, and polyurethane foam sheets. Among them, a PET film is preferable.

The thickness of the substrate (thickness of the entire substrate including the metal layer) is not particularly limited, but a preferable lower limit is 2 μm and a preferable upper limit is 30 μm. When the thickness of the base material is within the above range, peeling is less likely to occur even when the single-sided adhesive tape is folded back (bent) and attached to the edge of the metal-clad laminate. A more preferable lower limit of the thickness of the substrate is 4 μm, and a more preferable upper limit thereof is 20 μm.
The thickness of the metal layer in the substrate is not particularly limited, but the preferable lower limit of the ratio of the thickness of the metal layer to the thickness of the entire substrate is 0.1%. When the thickness ratio of the metal layer is 0.1% or more, the resistance of the single-sided pressure-sensitive adhesive tape to strong alkaline solutions is further enhanced. A more preferable lower limit of the thickness ratio of the metal layer is 1%. The upper limit of the thickness ratio of the metal layer is not particularly limited, and when the substrate is the metal substrate, the thickness ratio of the metal layer is 100%.

The upper limit of the coefficient of static friction of the heat-sensitive adhesive layer to SUS (stainless steel) is 5.
Since the heat-sensitive adhesive layer exhibits almost no adhesiveness at room temperature, when a part of the metal-clad laminate comes into contact with the heat-sensitive adhesive layer when the single-sided adhesive tape is attached to the edge of the metal-clad laminate, The heat-sensitive adhesive layer does not stick to the surface, and wrinkles are less likely to occur. Furthermore, since the coefficient of static friction with respect to SUS is 5 or less, the heat-sensitive adhesive layer can slide on the metal-clad laminate, so that the single-sided adhesive tape is attached to the edge of the metal-clad laminate. Even if a portion of the metal-clad laminate is in contact with the heat-sensitive adhesive layer, the contacting portion slides, making it possible to equalize the attaching stress. As a result, no load is applied to the base material, and wrinkles are less likely to occur. A preferable upper limit of the coefficient of static friction for SUS is 3, and a more preferable upper limit is 2. Although the lower limit of the coefficient of static friction with respect to SUS is not particularly limited, the practical lower limit is about 0.1.
The coefficient of static friction against SUS was measured using SUS304 (size 63 mm x 63 mm, weight 200 g) as a sliding piece, and at a tensile speed of 100 mm/min in accordance with JIS K7125 at room temperature (23°C) and humidity of 50%. can be measured at When measuring, put the single-sided adhesive tape as a sample on the other material, put the sliding piece as a weight on the single-sided adhesive tape, and pull the single-sided adhesive tape with a string to measure the resistance generated at that time. Measure the force (frictional force). As the mating material, SUS304 (size: 250 mm x 150 mm x thickness: 1.5 mm) can be used like the sliding piece.

The method for adjusting the coefficient of static friction within the above range is not particularly limited. A method of adjusting the elastic modulus G', the gel fraction, the surface roughness Ra, etc. within appropriate ranges can be mentioned.
More specifically, for example, as a method for adjusting the peak temperature of the loss tangent of the heat-sensitive adhesive layer, the storage elastic modulus G′ at 23° C., the gel fraction, etc., the base polymer contained in the heat-sensitive adhesive layer A method of adjusting the type, molecular weight and molecular weight distribution, the type and content of the tackifying resin, the type and content of the cross-linking agent, and the like can be mentioned. Further, as a method for adjusting the surface roughness Ra, when forming the heat-sensitive adhesive layer, a film (for example, release-treated PET) for coating the adhesive solution for forming the heat-sensitive adhesive layer a method of appropriately adjusting the surface roughness of the film). Since the surface roughness of the film used at this time is transferred to the surface of the heat-sensitive adhesive layer, the surface roughness of the heat-sensitive adhesive layer can be improved by appropriately adjusting the surface roughness of the film. Ra can be adjusted.

The heat-sensitive adhesive layer has a peak temperature of loss tangent (hereinafter also referred to as tan δ or simply loss tangent) measured at a measurement frequency of 1 Hz using a dynamic viscoelasticity measuring device, although the peak temperature is not particularly limited. Preferably.
When the peak temperature of the loss tangent is 40 ° C. or higher, it becomes easier to adjust the static friction coefficient to the SUS within the above range, and wrinkles are further suppressed when the single-sided adhesive tape is attached to the edge of the metal-clad laminate. can do. The peak temperature of the loss tangent is more preferably 42° C. or higher, even more preferably 45° C. or higher. The peak temperature of the loss tangent is preferably 100° C. or lower, more preferably 90° C. or lower, and even more preferably 80° C. or lower.
The loss tangent is measured using a dynamic viscoelasticity measuring device (DVA-200, manufactured by IT Keisoku Co., Ltd., or equivalent) under the conditions of 5 ° C./min and 1 Hz in a low-speed heating shear deformation mode. It can be obtained by measuring dynamic viscoelasticity spectrum from -40°C to 140°C.

The storage elastic modulus G' of the heat-sensitive adhesive layer is not particularly limited, but the preferred lower limit of the storage elastic modulus G' at 23°C is 5 MPa, and the preferred upper limit of the storage elastic modulus G' at 100°C is 0.2 MPa. .
If the storage elastic modulus G′ at 23° C. is 5 MPa or more, the heat-sensitive adhesive layer exhibits almost no adhesiveness at room temperature. can be further suppressed. A more preferable lower limit of the storage elastic modulus G' at 23°C is 8 MPa, and a more preferable lower limit is 10 MPa. Although the upper limit of the storage elastic modulus G' at 23°C is not particularly limited, the upper limit is preferably 10000 MPa, more preferably 1000 MPa, from the viewpoint that the single-sided adhesive tape can be easily rolled.

If the storage elastic modulus G′ at 100° C. is 0.2 MPa or less, the heat-sensitive adhesive layer exhibits sufficient adhesiveness by heating, so that the single-sided adhesive tape is brought into contact with the edge of the metal-clad laminate. The single-sided adhesive tape can be attached to the edge of the metal-clad laminate by adjusting the position and the like so that the single-sided adhesive tape does not wrinkle or float, and then heat-pressing it. A more preferable upper limit of the storage elastic modulus G' at 100°C is 0.1 MPa, and a further preferable upper limit is 0.08 MPa. The lower limit of the storage elastic modulus G′ at 100° C. is not particularly limited, but from the viewpoint of suppressing exudation due to deformation of the heat-sensitive adhesive layer during thermocompression bonding, a preferable lower limit is 0.01 MPa, and a more preferable lower limit is 0.05 MPa. is.
The storage modulus G′ at 23° C. or 100° C. is measured using a dynamic viscoelasticity measuring device (for example, “DVA-200” manufactured by IT Instrument Control Co., Ltd., “ARES” manufactured by Rheometrics Co., Ltd.). It can be obtained by measuring from −40° C. to 140° C. under the conditions of shear mode of physical viscoelasticity measurement, angular frequency of 1 Hz, and speed of 5° C./min.

The gel fraction of the heat-sensitive adhesive layer is not particularly limited, but the preferred lower limit is 50% by weight. When the gel fraction is 50% by weight or more, the heat-sensitive adhesive layer is prevented from being swelled by the strong alkaline solution, and the resistance of the single-sided adhesive tape to the strong alkaline solution becomes higher. In addition, if the gel fraction is 50% by weight or more, it becomes easier to adjust the coefficient of static friction to the SUS within the above range, and wrinkles are further suppressed when the single-sided adhesive tape is attached to the edge of the metal-clad laminate. can do. A more preferable lower limit of the gel fraction is 60% by weight. Although the upper limit of the gel fraction is not particularly limited, the upper limit is preferably 90% by weight, and the upper limit is more preferably 80% by weight, since the heat-sensitive adhesive layer tends to exhibit sufficient adhesiveness when heated.
In addition, the gel fraction can be measured by the following method.
0.1 g of only the heat-sensitive adhesive layer (adhesive composition) is taken out from the single-sided adhesive tape, immersed in 50 mL of ethyl acetate, and shaken with a shaker at a temperature of 23°C and 200 rpm for 24 hours. After shaking, a metal mesh (#200 mesh) is used to separate the ethyl acetate and the pressure-sensitive adhesive composition that has absorbed and swollen the ethyl acetate. The adhesive composition after separation is dried at 110° C. for 1 hour. The weight of the pressure-sensitive adhesive composition containing the metal mesh after drying is measured, and the gel fraction is calculated using the following formula.
Gel fraction (% by weight) = 100 x (W ₁ - W ₂ )/W ₀
(W ₀ : initial weight of adhesive composition, W ₁ : weight of adhesive composition containing metal mesh after drying, W ₂ : initial weight of metal mesh)

The surface roughness Ra of the heat-sensitive adhesive layer is not particularly limited, but the preferred lower limit is 0.01 μm and the preferred upper limit is 0.8 μm. If the surface roughness Ra is within the above range, it becomes easier to adjust the static friction coefficient to the above SUS within the above range, and wrinkles are further suppressed when the single-sided adhesive tape is attached to the edge of the metal-clad laminate. can be done. A more preferable lower limit of the surface roughness Ra is 0.02 μm, and a more preferable upper limit thereof is 0.1 μm.
The surface roughness Ra means arithmetic mean roughness defined in JIS B 0601-2001.

The heat-sensitive adhesive layer is not particularly limited, and for example, rubber-based, styrene-based, polyester-based, acrylic-based heat-sensitive adhesive layers can be used. Since it can be adhered to various adherends by thermocompression, it preferably contains an acrylic polymer.

The acrylic polymer contained in the heat-sensitive adhesive layer (hereinafter also referred to as the acrylic polymer for the heat-sensitive adhesive layer) is not particularly limited, but preferably has a structural unit derived from a monomer having a crosslinkable functional group. By having such a structural unit, the acrylic polymer for the heat-sensitive adhesive layer can be cross-linked when a cross-linking agent is used in combination. By adjusting the degree of crosslinking at that time, the storage elastic modulus G' of the heat-sensitive adhesive layer can be easily adjusted within the above range, and the coefficient of static friction against SUS can be easily adjusted within the above range.

Examples of the crosslinkable functional group include a hydroxyl group, a carboxyl group, a glycidyl group, an amino group, an amide group, and a nitrile group. Among them, a hydroxyl group or a carboxyl group is preferable because the storage elastic modulus G′ of the heat-sensitive adhesive layer can be easily adjusted.
Examples of the monomer having a hydroxyl group include (meth)acrylic acid esters having a hydroxyl group such as 4-hydroxybutyl (meth)acrylate and 2-hydroxyethyl (meth)acrylate. Examples of the monomer having a carboxyl group include (meth)acrylic acid. Examples of the monomer having a glycidyl group include glycidyl (meth)acrylate. Examples of the amide group-containing monomer include hydroxyethylacrylamide, isopropylacrylamide, and dimethylaminopropylacrylamide. Examples of the nitrile group-containing monomer include acrylonitrile. These monomers having a crosslinkable functional group may be used alone or in combination of two or more.
In this specification, (meth)acrylate means acrylate or methacrylate, and (meth)acryl means acrylic or methacrylic. The acrylic polymer may be a methacrylic polymer.

The content of the structural unit derived from the monomer having a crosslinkable functional group in the acrylic polymer for the heat-sensitive adhesive layer is not particularly limited, but the preferred lower limit is 0.1% by weight and the preferred upper limit is 5% by weight.
Further, when a monomer having a carboxyl group is used as the monomer having a crosslinkable functional group, the resistance of the single-sided adhesive tape to a strong alkaline solution is further increased. A more preferable upper limit of the content is 3% by weight, and a further preferable upper limit is 0.5% by weight.

The acrylic polymer for the heat-sensitive adhesive layer preferably has a structural unit derived from (meth)acrylate having an alkyl group having 1 to 4 carbon atoms, and has an alkyl group having 1 to 4 carbon atoms. It is more preferable to have structural units derived from methacrylate. Moreover, the acrylic polymer for the heat-sensitive adhesive layer preferably has a structural unit derived from (meth)acrylate having an alkyl group having a cyclic structure.
When the acrylic polymer for the heat-sensitive adhesive layer has these structural units, it becomes easier to adjust the peak temperature of the loss tangent of the heat-sensitive adhesive layer and the storage elastic modulus G' within the above range, and the static friction against the SUS Since it becomes easier to adjust the coefficient within the above range, wrinkles can be further suppressed when the single-sided adhesive tape is attached to the edge of the metal-clad laminate. The acrylic polymer for the heat-sensitive adhesive layer is selected from the group consisting of a structural unit derived from a methacrylate having an alkyl group having 1 to 4 carbon atoms and a structural unit derived from a methacrylate having an alkyl group having a cyclic structure. It is more preferable to have at least one selected.

The (meth)acrylate having an alkyl group having 1 to 4 carbon atoms is not particularly limited, and examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, and the like. mentioned. The (meth)acrylate having an alkyl group having a cyclic structure is not particularly limited, and examples thereof include cyclohexyl (meth)acrylate and isobornyl (meth)acrylate. These (meth)acrylates may be used alone or in combination of two or more. Among them, it is selected from the group consisting of methyl methacrylate, butyl acrylate, butyl methacrylate and isobornyl methacrylate, since the peak temperature of the loss tangent and the storage elastic modulus G′ of the heat-sensitive adhesive layer can be easily adjusted to more preferable ranges. It is preferable to use at least one of

Structural units derived from the (meth)acrylate having an alkyl group having 1 to 4 carbon atoms in the acrylic polymer for the heat-sensitive adhesive layer, and derived from the (meth)acrylate having an alkyl group having a cyclic structure Although the total content of the constituent units is not particularly limited, the preferable lower limit is 50% by weight and the preferable upper limit is 98% by weight. If the total content of the structural units is within the above range, the peak temperature of the loss tangent and the storage elastic modulus G′ of the heat-sensitive adhesive layer can be easily adjusted within the above range, and the static friction coefficient for the SUS is within the above range. Therefore, wrinkles can be further suppressed when the single-sided adhesive tape is attached to the edge of the metal-clad laminate. A more preferable lower limit of the total content of the structural units is 60% by weight, a more preferable lower limit is 70% by weight, a more preferable upper limit is 95% by weight, a still more preferable upper limit is 90% by weight, and a still more preferable upper limit is 80% by weight. is.
In addition, the total content is a structural unit derived from a (meth)acrylate having an alkyl group having 1 to 4 carbon atoms, and a structural unit derived from a (meth)acrylate having an alkyl group having a cyclic structure. The acrylic polymer for the heat-sensitive adhesive layer may contain either one or both of them.

Further, the total content of the structural units derived from the methacrylate having an alkyl group having 1 to 4 carbon atoms and the structural unit derived from the methacrylate having an alkyl group having a cyclic structure in the acrylic polymer for the heat-sensitive adhesive layer From the same point of view, the preferred lower limit is 50% by weight and the preferred upper limit is 90% by weight. A more preferable lower limit of the above total content is 60% by weight, and a more preferable upper limit is 80% by weight.

The acrylic polymer for the heat-sensitive adhesive layer may further have structural units derived from other monomers as long as the effects of the present invention are not impaired. Examples of the other monomers include n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, Lauryl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, ethyl carbitol (meth)acrylate, vinyl acetate, fluorine-containing (meth)acrylate, etc. is mentioned.
In addition, when the acrylic polymer for the heat-sensitive adhesive layer is prepared by an ultraviolet polymerization method, it preferably further contains structural units derived from polyfunctional monomers such as divinylbenzene and trimethylolpropane tri(meth)acrylate. .

The solubility parameter (SP value) of the acrylic polymer for the heat-sensitive adhesive layer is not particularly limited, but the preferred lower limit is 9.2 and the preferred upper limit is 10.5. When the SP value is within the above range, the heat-sensitive adhesive layer is prevented from being swelled by a strong alkaline solution, and the resistance of the single-sided adhesive tape to a strong alkaline solution is increased. Further, when the SP value is within the above range, the adhesion of the heat-sensitive adhesive layer to the metal-clad laminate is increased, and the metal-clad laminate can be sufficiently protected. The SP value has a more preferable lower limit of 9.5, a more preferable upper limit of 10.2, a still more preferable lower limit of 9.6, and a still more preferable upper limit of 10.
The solubility parameter (SP value) means the solubility parameter (SP value) ((cal/cm ³ ) ^0.5 ) according to the Fedors method, and is calculated according to the Fedors method (RF Fedors, Polym. Eng. Sci. , 14(2), 147-154 (1974)) and is an index capable of expressing the ease of dissolution.

The weight average molecular weight (Mw) of the acrylic polymer for the heat-sensitive adhesive layer is not particularly limited, but the preferred lower limit is 250,000, the preferred upper limit is 2,000,000, the more preferred lower limit is 300,000, and the further preferred lower limit is 400,000. and a more preferable upper limit is 1,500,000.
The weight-average molecular weight (Mw) can be adjusted by polymerization conditions (eg, type or amount of polymerization initiator, polymerization temperature, monomer concentration, etc.). Moreover, the weight average molecular weight (Mw) can be measured by the following method.
The acrylic polymer solution is filtered through a filter (material: polytetrafluoroethylene, pore diameter: 0.2 μm). The obtained filtrate is supplied to a gel permeation chromatograph (e.g., Waters, 2690 Separations Model), and GPC measurement is performed under the conditions of a sample flow rate of 1 ml/min and a column temperature of 40 ° C., and the acrylic polymer is converted to polystyrene. The molecular weight is measured to determine the weight average molecular weight (Mw). As the column, for example, GPC KF-806L or GPC LF-804 (manufactured by Showa Denko KK) is used, and as the detector, a differential refractometer is used.

The method for preparing the acrylic polymer for the heat-sensitive adhesive layer is not particularly limited, and examples thereof include a method of radically reacting the monomers from which the structural units are derived in the presence of a polymerization initiator. The polymerization method is not particularly limited, and conventionally known methods can be used. Examples thereof include solution polymerization (boiling point polymerization or constant temperature polymerization), emulsion polymerization, suspension polymerization, bulk polymerization and the like. Among them, solution polymerization is preferable from the viewpoint of ease of synthesis and water resistance.

When solution polymerization is used as the polymerization method, examples of reaction solvents include ethyl acetate, toluene, methyl ethyl ketone, methyl sulfoxide, ethanol, acetone, and diethyl ether. These reaction solvents may be used alone or in combination of two or more.

The polymerization initiator is not particularly limited, and examples thereof include organic peroxides and azo compounds. Examples of the organic peroxide include 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane, t-hexylperoxypivalate, t-butylperoxypivalate, 2,5 -dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxy isobutyrate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate and the like. Examples of the azo compound include azobisisobutyronitrile and azobiscyclohexanecarbonitrile. These polymerization initiators may be used alone or in combination of two or more.

The heat-sensitive adhesive layer preferably further contains a tackifying resin.
By containing the tackifying resin in the heat-sensitive adhesive layer, the interfacial adhesion is improved when the single-sided adhesive tape is heat-pressed, and the resistance of the single-sided adhesive tape to strong alkaline solutions is further increased.
The tackifying resin is not particularly limited, and examples thereof include coumarone resins, terpene resins, terpene phenol resins, rosin resins, rosin derivative resins, petroleum resins, alkylphenol resins, and hydrides thereof. These tackifying resins may be used alone or in combination of two or more.

The terpene phenolic resin means a polymer containing terpene residues and phenol residues. In addition, terpene phenol resins include copolymers of terpene and phenol compounds (terpene-phenol copolymer resins), and homopolymers or copolymers of terpene (terpene resins, typically unmodified terpene resins). is a concept including phenol-modified terpene resins modified with phenol, and resins obtained by hydrogenating the terpene sites in these resins.

The terpene constituting the terpene phenol resin is not particularly limited, but monoterpenes such as α-pinene, β-pinene, limonene and camphene are preferable. Limonene includes d-form, l-form and d/l-form (dipentene).

More specific examples of the rosin resin include unmodified rosins (fresh rosins) such as gum rosin, wood rosin and tall oil rosin, modified rosins obtained by modifying these unmodified rosins, and the like. Modification of the modified rosin includes, for example, hydrogenation, disproportionation, and polymerization. More specific examples of the modified rosin include hydrogenated rosin, disproportionated rosin, polymerized rosin, and other chemically modified rosins.

As the rosin derivative resin, more specifically, for example, a rosin ester resin obtained by esterifying the rosin resin with an alcohol, an unsaturated fatty acid-modified rosin resin obtained by modifying the rosin resin with an unsaturated fatty acid, and an unsaturated rosin ester resin. Unsaturated fatty acid-modified rosin ester resin modified with saturated fatty acid and the like can be mentioned. Examples of the rosin derivative resin include rosin alcohol resin obtained by reducing the carboxyl group in the unsaturated fatty acid-modified rosin resin or unsaturated fatty acid-modified rosin ester resin.
Further, examples of the rosin derivative resins include metal salts of the rosin resins or rosin derivative resins (particularly, rosin ester resins), rosin phenol resins, and the like. The rosin phenol resin can be obtained by adding phenol to the above rosin resin or rosin derivative resin under an acid catalyst, followed by thermal polymerization.

More specifically, the petroleum resins include aliphatic (C5) petroleum resins, aromatic (C9) petroleum resins, C5/C9 copolymer petroleum resins, alicyclic petroleum resins, and Hydrogenated products thereof and the like are included.

In particular, the tackifier resin preferably has a softening point of 100° C. or higher and a hydroxyl value of 25 mgKOH/g or higher. By containing such a tackifying resin in the heat-sensitive adhesive layer, the interfacial adhesion is improved when the single-sided adhesive tape is heat-pressed, and the resistance of the single-sided adhesive tape to strong alkaline solutions is further increased. Furthermore, the tackifying resin more preferably contains a hydrogenated rosin ester resin having a hydroxyl value of 40 mgKOH/g or more. Although the upper limit of the hydroxyl value of the hydrogenated rosin ester resin having a hydroxyl value of 40 mgKOH/g or more is not particularly limited, it is usually about 80 mgKOH/g, preferably 50 mgKOH/g or less.

The content of the tackifying resin is not particularly limited, but the preferred lower limit is 5 parts by weight, the preferred upper limit is 50 parts by weight, and the more preferred lower limit is 10 parts by weight, with respect to 100 parts by weight of the acrylic polymer for the heat-sensitive adhesive layer. A more preferable upper limit is 35 parts by weight. When the content of the tackifying resin is within the above range, the interfacial adhesion is improved when the single-sided adhesive tape is heat-pressed, and the resistance of the single-sided adhesive tape to strong alkaline solutions is further enhanced.

The heat-sensitive adhesive layer may contain a silane coupling agent.
By containing the silane coupling agent in the heat-sensitive adhesive layer, the interfacial adhesion is improved when the single-sided adhesive tape is heat-pressed, and the resistance of the single-sided adhesive tape to strong alkaline solutions is further increased.

The silane coupling agent is not particularly limited, and examples include vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-glycidoxypropyltrimethoxysilane. , γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-amino Propyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethylmethoxysilane, N-(2-aminoethyl)3-aminopropyltriethoxysilane, N-(2-aminoethyl)3-aminopropylmethyl dimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, mercaptobutyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane and the like. Among them, γ-glycidoxypropyltriethoxysilane and γ-mercaptopropyltrimethoxysilane are preferred.

The content of the silane coupling agent is not particularly limited, but the preferred lower limit is 0.1 parts by weight and the preferred upper limit is 5 parts by weight with respect to 100 parts by weight of the acrylic polymer for the heat-sensitive adhesive layer. When the content of the silane coupling agent is within this range, the interfacial adhesion is improved when the single-sided pressure-sensitive adhesive tape is heat-pressed, and the resistance of the single-sided pressure-sensitive adhesive tape to strong alkaline solutions is further increased. A more preferable lower limit to the content of the silane coupling agent is 0.5 parts by weight, and a more preferable upper limit is 3 parts by weight.

The heat-sensitive adhesive layer may further contain a cross-linking agent.
When the heat-sensitive adhesive layer contains the cross-linking agent, the acrylic polymer for the heat-sensitive adhesive layer contains a structural unit derived from a monomer having a cross-linkable functional group. It is possible to crosslink between the system polymers.
The cross-linking agent is not particularly limited, and examples thereof include isocyanate-based cross-linking agents, aziridine-based cross-linking agents, epoxy-based cross-linking agents, and metal chelate-type cross-linking agents. Among them, an isocyanate-based cross-linking agent and an epoxy-based cross-linking agent are preferable. Furthermore, by reacting with the constituent units derived from the monomer having the crosslinkable functional group, an ester bond that is difficult to hydrolyze is formed, so that the resistance of the single-sided adhesive tape to strong alkaline solutions is further increased. A cross-linking agent is more preferred.

The content of the crosslinking agent is not particularly limited, but the preferred lower limit is 0.01 parts by weight, the preferred upper limit is 10 parts by weight, and the more preferred lower limit is 0.1 parts by weight, per 100 parts by weight of the acrylic polymer for the heat-sensitive adhesive layer. Parts by weight, a more preferred upper limit is 5 parts by weight.

The heat-sensitive adhesive layer may contain additives such as plasticizers, emulsifiers, softeners, fillers, pigments and dyes, and other resins, if necessary.

The thickness of the heat-sensitive adhesive layer is not particularly limited, but the preferred lower limit is 5 µm and the preferred upper limit is 100 µm. When the thickness is within the above range, the single-sided adhesive tape can be satisfactorily heat-pressed, wrinkles at that time can be further suppressed, and the single-sided adhesive tape has a higher resistance to strong alkaline solutions. A more preferable lower limit of the thickness is 10 μm, a more preferable upper limit is 50 μm, a still more preferable lower limit is 20 μm, and a further preferable upper limit is 40 μm.
Moreover, the thickness of the heat-sensitive adhesive layer is preferably thicker than 1/2 of the thickness of the metal-clad laminate used as the adherend. In such a case, even if a single-sided adhesive tape is attached to the edge of the metal-clad laminate so as to extend from the front surface to the back surface of the metal-clad laminate, the edge of the metal-clad laminate and the heat-sensitive adhesive A gap is less likely to occur with the agent layer, and peeling is less likely to occur. More preferably, the thickness of the heat-sensitive adhesive layer is thicker than 2/3 of the thickness of the metal-clad laminate.

The single-sided adhesive tape preferably further has a pressure-sensitive adhesive layer between the substrate and the heat-sensitive adhesive layer. As a result, the anchoring property between the substrate and the heat-sensitive adhesive layer is increased, so that the resistance of the single-sided pressure-sensitive adhesive tape to strong alkaline solutions is increased.

The storage elastic modulus G' of the pressure-sensitive adhesive layer is not particularly limited, but the preferred upper limit of the storage elastic modulus G' at 23°C is 0.2 MPa. When the storage elastic modulus G′ at 23° C. is 0.2 MPa or less, the anchoring property between the substrate and the heat-sensitive adhesive layer is further improved. A more preferable upper limit of the storage modulus G' at 23°C is 0.15 MPa. The lower limit of the storage elastic modulus G' at 23°C is not particularly limited, but from the viewpoint of maintaining the cohesive strength of the pressure-sensitive adhesive layer, the preferred lower limit is 0.01 MPa, and the more preferred lower limit is 0.03 MPa.
The storage modulus at 23 ° C. is measured using a dynamic viscoelasticity measuring device (for example, "DVA-200" manufactured by IT Instrument Control Co., Ltd., "ARES" manufactured by Rheometrics, etc.). It can be obtained by measuring from −40° C. to 140° C. under the conditions of shear mode, angular frequency of 1 Hz, and speed of 5° C./min.

The storage elastic modulus G′ at 23° C. can be adjusted by the type, molecular weight and molecular weight distribution of the base polymer contained in the pressure-sensitive adhesive layer, the type and content of the tackifying resin, the type and content of the cross-linking agent, and the like. .

The pressure-sensitive adhesive layer is not particularly limited, and for example, rubber-based, styrene-based, polyester-based, acrylic-based pressure-sensitive adhesive layers can be used. and exhibits adhesiveness at room temperature and can be adhered to various adherends, and therefore, it preferably contains an acrylic polymer.

The acrylic polymer contained in the pressure-sensitive adhesive layer (hereinafter also referred to as acrylic polymer for pressure-sensitive adhesive layer) is not particularly limited. The acrylic polymer for the pressure-sensitive adhesive layer contains an acrylic acid alkyl ester and/or methacrylic acid alkyl ester having an alkyl group having a carbon number of 1 to 18 as a main monomer, and if necessary, a crosslinkable functional It is preferably a (meth)acrylic acid ester copolymer obtained by copolymerizing a monomer having a group by a conventional method. In addition, other copolymerizable modifying monomers may be copolymerized.

The acrylic polymer for the pressure-sensitive adhesive layer preferably has structural units derived from a monomer having a crosslinkable functional group. By having such a structural unit, the acrylic polymer for the pressure-sensitive adhesive layer can be cross-linked when a cross-linking agent is used in combination. By adjusting the degree of crosslinking at that time, the storage elastic modulus G' of the pressure-sensitive adhesive layer can be adjusted.

Examples of the crosslinkable functional group include a hydroxyl group, a carboxyl group, a glycidyl group, an amino group, an amide group, and a nitrile group. Among them, a hydroxyl group or a carboxyl group is preferable because the storage elastic modulus G′ of the pressure-sensitive adhesive layer can be easily adjusted.
Examples of the monomer having a hydroxyl group include (meth)acrylic acid esters having a hydroxyl group such as 4-hydroxybutyl (meth)acrylate and 2-hydroxyethyl (meth)acrylate. Examples of the monomer having a carboxyl group include (meth)acrylic acid. Examples of the monomer having a glycidyl group include glycidyl (meth)acrylate. Examples of the amide group-containing monomer include hydroxyethylacrylamide, isopropylacrylamide, and dimethylaminopropylacrylamide. Examples of the nitrile group-containing monomer include acrylonitrile. These monomers having a crosslinkable functional group may be used alone or in combination of two or more.

The content of the structural unit derived from the monomer having a crosslinkable functional group in the acrylic polymer for the pressure-sensitive adhesive layer is not particularly limited, but the preferred lower limit is 0.1% by weight and the preferred upper limit is 5% by weight. .
Further, when a monomer having a carboxyl group is used as the monomer having a crosslinkable functional group, the resistance of the single-sided adhesive tape to a strong alkaline solution is further increased. A more preferable upper limit of the content is 3% by weight, and a further preferable upper limit is 0.5% by weight.

The acrylic polymer for the pressure-sensitive adhesive layer preferably has a structural unit derived from (meth)acrylate having an alkyl group with 8 or more carbon atoms. By having such a structural unit, the hydrophobicity of the acrylic polymer for the pressure-sensitive adhesive layer is increased, and the infiltration of a strong alkaline solution into the molecular chain is further suppressed. is more resistant to

Examples of the (meth)acrylate having an alkyl group having 8 or more carbon atoms include n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl ( meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, isobornyl (meth)acrylate and the like. These (meth)acrylates having an alkyl group with 8 or more carbon atoms may be used alone or in combination of two or more. Among them, 2-ethylhexyl acrylate, lauryl acrylate, and lauryl methacrylate are preferably used because the pressure-sensitive adhesive layer does not become too hard and sufficient tackiness can be maintained.

The content of the structural unit derived from the (meth)acrylate having an alkyl group having 8 or more carbon atoms in the acrylic polymer for the pressure-sensitive adhesive layer is not particularly limited, but the preferred lower limit is 15% by weight, and the preferred upper limit is 99% by weight. When the content of the (meth)acrylate having an alkyl group having 8 or more carbon atoms is within the above range, the hydrophobicity of the acrylic polymer for the pressure-sensitive adhesive layer is increased, and a strong alkaline solution enters the molecular chain. is further suppressed, the resistance of the single-sided adhesive tape to strong alkaline solutions is further increased. A more preferable lower limit to the content of the structural unit derived from the (meth)acrylate having an alkyl group having 8 or more carbon atoms is 20% by weight, and a more preferable upper limit is 30% by weight.

The above acrylic polymer for the pressure-sensitive adhesive layer may further have structural units derived from other monomers to the extent that the effects of the present invention are not impaired. Examples of the above other monomers include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, ethyl carbitol (meth) ) acrylate, vinyl acetate, fluorine-containing (meth)acrylate, and the like.
When the acrylic polymer for the pressure-sensitive adhesive layer is prepared by an ultraviolet polymerization method, it may further contain structural units derived from polyfunctional monomers such as divinylbenzene and trimethylolpropane tri(meth)acrylate. preferable.

The solubility parameter (SP value) of the acrylic polymer for the pressure-sensitive adhesive layer is not particularly limited, and is the same as the solubility parameter (SP value) of the acrylic polymer for the heat-sensitive adhesive layer. you can

The weight-average molecular weight (Mw) of the acrylic polymer for the pressure-sensitive adhesive layer is not particularly limited, and may be the same weight-average molecular weight (Mw) as the weight-average molecular weight (Mw) of the acrylic polymer for the heat-sensitive adhesive layer. you can

The method for preparing the acrylic polymer for the pressure-sensitive adhesive layer is not particularly limited, and in the same manner as in the case of the acrylic polymer for the heat-sensitive adhesive layer, for example, a monomer from which the structural unit is derived may be added as a polymerization initiator. and a method of radical reaction in the presence of.

The pressure-sensitive adhesive layer preferably further contains a tackifying resin.
By containing the tackifying resin in the pressure-sensitive adhesive layer, the adhesive strength of the pressure-sensitive adhesive layer is improved. The tackifying resin is not particularly limited, and the same tackifying resin as that used in the heat-sensitive adhesive layer can be used.
The content of the tackifying resin is not particularly limited, but the preferred lower limit is 3 parts by weight, the preferred upper limit is 50 parts by weight, and the more preferred lower limit is 10 parts by weight, relative to 100 parts by weight of the acrylic polymer for the pressure-sensitive adhesive layer. , and a more preferred upper limit is 35 parts by weight. When the content of the tackifier resin is within the above range, the adhesive strength of the pressure-sensitive adhesive layer is improved.

The pressure-sensitive adhesive layer may contain a silane coupling agent.
The silane coupling agent is not particularly limited, and the same silane coupling agent as the silane coupling agent used in the heat-sensitive adhesive layer can be used. The content of the silane coupling agent is also not particularly limited, and the same content as the content in the heat-sensitive adhesive layer can be employed.

The pressure-sensitive adhesive layer may further contain a cross-linking agent.
When the pressure-sensitive adhesive layer contains the cross-linking agent, and the acrylic polymer for the pressure-sensitive adhesive layer contains a structural unit derived from the monomer having the crosslinkable functional group, the pressure-sensitive adhesive Cross-linking can be performed between the layer acrylic polymers.
The cross-linking agent is not particularly limited, and the same cross-linking agent as that used in the heat-sensitive adhesive layer can be used, and an epoxy-based cross-linking agent is more preferable. The content of the cross-linking agent is also not particularly limited, and the same content as the content in the heat-sensitive adhesive layer can be adopted.

The pressure-sensitive adhesive layer may contain additives such as plasticizers, emulsifiers, softeners, fillers, pigments and dyes, and other resins, if necessary.　

The gel fraction of the pressure-sensitive adhesive layer is not particularly limited, and may be the same as that of the heat-sensitive adhesive layer, preferably 50% by weight or more.
The thickness of the pressure-sensitive adhesive layer is not particularly limited, but the preferred lower limit is 0.1 μm and the preferred upper limit is 30 μm. When the thickness of the pressure-sensitive adhesive layer is within the above range, the anchoring property between the substrate and the heat-sensitive adhesive layer is further improved. A more preferable lower limit of the thickness of the pressure-sensitive adhesive layer is 5 μm, and a more preferable upper limit thereof is 20 μm.

As described above, as one aspect of the present invention, a base material and a heat-sensitive adhesive layer laminated on one surface of the base material are provided, and the base material has at least the surface opposite to the heat-sensitive adhesive layer. , a single-sided pressure-sensitive adhesive tape having a metal layer was described, but based on the relationship between the heat-sensitive adhesive layer and the metal layer instead of the relationship between the substrate, the heat-sensitive adhesive layer, and the metal layer, in the present invention, It can be said that the single-sided pressure-sensitive adhesive tape may have the above-mentioned metal layer as a member constituting the above-mentioned base material disposed on the surface opposite to the above-mentioned heat-sensitive adhesive layer. That is, as another aspect of the present invention, there is provided a single-sided adhesive tape having a metal layer on one side and a heat-sensitive adhesive layer on the other side, wherein the heat-sensitive adhesive layer has a static friction coefficient of 5 against SUS. The following are single-sided adhesive tapes. Even in such a different embodiment, it is possible to realize a single-sided pressure-sensitive adhesive tape that is less likely to wrinkle when attached to a thin adherend and has excellent resistance to strong alkaline solutions.

The method for producing the single-sided pressure-sensitive adhesive tape of the present invention is not particularly limited. After coating on a release-treated PET film, it is dried to form a heat-sensitive adhesive layer, and the heat-sensitive adhesive layer is transferred to a base material.

The use of the single-sided adhesive tape of the present invention is not particularly limited, but it is less likely to wrinkle when attached to a thin adherend and has excellent resistance to strong alkaline solutions. It can be preferably used in some cases. Among them, the single-sided pressure-sensitive adhesive tape of the present invention is particularly suitable for attaching to the edge of the metal-clad laminate to protect the edge of the metal-clad laminate in the etching process, the desmear process, or the electroless plating process. can be used for
More specifically, the single-sided adhesive tape of the present invention is a metal-clad laminate, especially a thin one (specifically, a thickness of 100 μm or less, preferably around 20 to 50 μm, especially around 30 to 40 μm). It can be used to protect the edge of the metal-clad laminate by attaching it to the edge of the metal-clad laminate.
After completion of the process, the region protected by the single-sided adhesive tape can be separated (removed) by trimming the region of the metal-clad laminate protected by the single-sided adhesive tape.

The method of protecting the edges of the metal-clad laminate by attaching the single-sided adhesive tape of the present invention to the edges of the metal-clad laminate is not particularly limited. and a method of thermocompression bonding to the end of the . As conditions for thermocompression bonding, for example, a temperature of 80 to 120° C., a pressure of 0.1 to 5 MPa, and a time of 30 to 300 seconds can be used. When the single-sided adhesive tapes are attached to the squares of the metal-clad laminate, the single-sided adhesive tapes may be attached overlappingly or may be attached so as not to overlap.

1 to 8 are cross-sectional views schematically showing an example of a state in which the edge of a metal-clad laminate is protected using the single-sided pressure-sensitive adhesive tape of the present invention.
In the edge-protected metal-clad laminate 1 shown in FIGS. 1-4, a single-sided adhesive tape 30 having a substrate 31 and a heat-sensitive adhesive layer 32 is used. 1 to 4, the single-sided adhesive tape 30 is folded back (bent) and attached to the end portion of the metal-clad laminate 2 so as to extend from the front surface to the back surface of the metal-clad laminate 2. In FIGS. Furthermore, in FIG. 4 , the entire back surface of the metal-clad laminate 2 is covered with a single-sided adhesive tape 30 .
In the edge-protected metal-clad laminate 1 shown in FIGS. Adhesive tape 30' is used.
In the edge-protected metal-clad laminate 1 shown in FIG. 30' and a single-sided adhesive tape 30'' having a substrate 31'' and a heat-sensitive adhesive layer 32'' are used.

In FIGS. 2 to 8, 3a indicates the interface between the heat-sensitive adhesive layers, and by minimizing the gap at this interface 3a, damage to the edges of the metal-clad laminate 2 can be further suppressed. It is possible to further suppress the infiltration of the solution into the end portion even when exposed to a strong alkaline solution.

According to the present invention, it is possible to provide a single-sided pressure-sensitive adhesive tape that is less likely to wrinkle when attached to a thin adherend and has excellent resistance to strong alkaline solutions.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view schematically showing an example of a state in which the edge of a metal-clad laminate is protected using the single-sided pressure-sensitive adhesive tape of the present invention; BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view schematically showing an example of a state in which the edge of a metal-clad laminate is protected using the single-sided pressure-sensitive adhesive tape of the present invention; BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view schematically showing an example of a state in which the edge of a metal-clad laminate is protected using the single-sided pressure-sensitive adhesive tape of the present invention; BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view schematically showing an example of a state in which the edge of a metal-clad laminate is protected using the single-sided pressure-sensitive adhesive tape of the present invention; BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view schematically showing an example of a state in which the edge of a metal-clad laminate is protected using the single-sided pressure-sensitive adhesive tape of the present invention; BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view schematically showing an example of a state in which the edge of a metal-clad laminate is protected using the single-sided pressure-sensitive adhesive tape of the present invention; BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view schematically showing an example of a state in which the edge of a metal-clad laminate is protected using the single-sided pressure-sensitive adhesive tape of the present invention; BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view schematically showing an example of a state in which the edge of a metal-clad laminate is protected using the single-sided pressure-sensitive adhesive tape of the present invention;

EXAMPLES The aspects of the present invention will be described in more detail with reference to Examples below, but the present invention is not limited only to these Examples.

The tackifying resins used in Examples and Comparative Examples are shown below.
・ Hydrogenated rosin ester resin (manufactured by Arakawa Chemical Industries, Ltd., KE-359, softening point 100 ° C., hydroxyl value 42 mg KOH / g)
・Hydrogenated rosin ester resin (manufactured by Arakawa Chemical Industries, Ltd., KE-311, softening point 100 ° C., hydroxyl value 8 mg KOH / g)
・Hydrogenated rosin ester resin (manufactured by Arakawa Chemical Industries, Ltd., ester gum H, softening point 68° C., hydroxyl value 29 mgKOH/g)
・ Disproportionated rosin ester resin (manufactured by Arakawa Chemical Industries, Ltd., KE-100, softening point 100 ° C., hydroxyl value 6 mg KOH / g)
・ Disproportionated rosin ester resin (manufactured by Arakawa Chemical Industries, Ltd., A-100, softening point 100 ° C., hydroxyl value 16 mg KOH / g)
・ Polymerized rosin ester resin (manufactured by Arakawa Chemical Industries, Ltd., D-135, softening point 135 ° C., hydroxyl value 45 mg KOH / g)

(Example 1)
(1) Preparation of acrylic polymer Ethyl acetate was added as a polymerization solvent into a reaction vessel, and nitrogen was bubbled through the reaction vessel. Subsequently, a polymerization initiator solution obtained by diluting 0.3 parts by weight of azobisisobutyronitrile 10 times with ethyl acetate as a polymerization initiator was charged into the reaction vessel, and a total of 100 parts by weight of monomers having the composition shown in Table 1 was added. was added dropwise over 2 hours. After the completion of dropping, a polymerization initiator solution obtained by diluting 0.3 parts by weight of azobisisobutyronitrile 10 times with ethyl acetate as a polymerization initiator was put into the reaction vessel again, and the polymerization reaction was performed for 4 hours to obtain an acrylic polymer. A containing solution was obtained.
A solubility parameter (SP value) was determined for the obtained acrylic polymer. Further, the weight average molecular weight (Mw) in terms of polystyrene was determined for the obtained acrylic polymer by gel permeation chromatography using GPC LF-804 (manufactured by Showa Denko KK) as a column.

(2) Production of Single-Sided Adhesive Tape To the obtained acrylic polymer-containing solution, 1 part by weight of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., KBM803) per 100 parts by weight of the acrylic polymer, a cross-linking agent (epoxy-based A cross-linking agent, Tetrad C, manufactured by Mitsubishi Gas Chemical Co., Ltd., was added in an amount of 0.3 parts by weight (solid component ratio) to prepare an adhesive solution.
The obtained adhesive solution was coated on a release-treated PET film (manufactured by Toyo Cloth Co., Ltd., SP3000-75) with a thickness of 75 μm so that the thickness of the heat-sensitive adhesive layer after drying would be the thickness shown in Table 1. After that, it was dried at 110° C. for 5 minutes to form a heat-sensitive adhesive layer. This heat-sensitive adhesive layer was transferred to an electrolytic copper foil (thickness 18 μm, manufactured by Fukuda Metal Foil Powder Industry Co., Ltd.) as a base material at 100 ° C. and cured at 40 ° C. for 48 hours. , and the release-treated PET film were laminated in this order to obtain a single-sided adhesive tape.

(3) Measurement of gel fraction 0.1 g of only the heat-sensitive adhesive layer (adhesive composition) was taken out from the single-sided adhesive tape, immersed in 50 mL of ethyl acetate, and shaken at 23°C and 200 rpm for 24 hours. Time was shaken. After shaking, ethyl acetate and the adhesive composition swollen by absorbing ethyl acetate were separated using a metal mesh (#200 mesh opening). The adhesive composition after separation was dried at 110° C. for 1 hour. The weight of the pressure-sensitive adhesive composition containing the metal mesh after drying was measured, and the gel fraction was calculated using the following formula.
Gel fraction (% by weight) = 100 x (W ₁ - W ₂ )/W ₀
(W ₀ : initial weight of adhesive composition, W ₁ : weight of adhesive composition containing metal mesh after drying, W ₂ : initial weight of metal mesh)

(4) Measurement of Storage Modulus G' and Peak Temperature of Loss Tangent A measurement sample consisting of only a heat-sensitive adhesive layer of 10 mm×6 mm and 1 mm in thickness was prepared in the same manner as in the Examples.
The resulting measurement sample was measured using a dynamic viscoelasticity measuring device (DVA-200, manufactured by IT Keisoku Co., Ltd.) under the conditions of shear mode for dynamic viscoelasticity measurement, angular frequency of 1 Hz, and speed of 5 ° C./min. Dynamic viscoelasticity measurement was performed from -40°C to 140°C, and the storage elastic modulus G' at 23°C and 100°C was measured. Furthermore, using a dynamic viscoelasticity measuring device (DVA-200, manufactured by IT Keisoku Co., Ltd.), the dynamic viscosity of -40 ° C to 140 ° C under the conditions of 5 ° C / min and 1 Hz in the slow heating shear deformation mode. The peak temperature of the loss tangent was measured by measuring the elastic spectrum.

(5) Measurement of static friction coefficient SUS304 (size 63 mm x 63 mm, weight 200 g, manufactured by Yutaka Panel Service) was used as a sliding piece, and tensile speed was 100 mm / min in accordance with JIS K7125. , and a humidity of 50%. SUS304 (size 250 mm×150 mm×thickness 1.5 mm, manufactured by Yutaka Panel Service Co., Ltd.) was used as the mating material of the sample in the measurement, like the sliding piece.

(6) Measurement of Surface Roughness Ra With respect to the heat-sensitive adhesive layer of the single-sided adhesive tape, the arithmetic mean roughness specified in JIS B 0601-2001 was measured to obtain the surface roughness Ra.

(Examples 2-3, Comparative Example 1)
A single-sided adhesive tape was obtained in the same manner as in Example 1, except for the changes shown in the table.

(Example 4)
(1) Preparation of acrylic polymer In the same manner as in Example 1, a solution containing the acrylic polymer used for the heat-sensitive adhesive layer (acrylic polymer for the heat-sensitive adhesive layer) and the acrylic polymer used for the pressure-sensitive adhesive layer were prepared. (acrylic polymer for pressure-sensitive adhesive layer) was prepared.

(2) Production of Single-sided Adhesive Tape Into the obtained acrylic polymer-containing solution for the heat-sensitive adhesive layer, hydrogenated rosin ester resin (KE-359, manufactured by Arakawa Chemical Industries, Ltd., softening point 100° C., hydroxyl value 42 mgKOH/g) was added in 30 parts by weight. Furthermore, 1 part by weight of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., KBM803) and 0.3 parts by weight (solid component ratio) of a cross-linking agent (epoxy cross-linking agent, manufactured by Mitsubishi Gas Chemical Co., Ltd., Tetrad C) are added, An adhesive solution for a heat-sensitive adhesive layer was prepared.
In addition, a polymerized rosin ester resin (manufactured by Arakawa Chemical Industries, Ltd., D-135, softening point 135° C., hydroxyl value 45 mg KOH /g) was added in an amount of 15 parts by weight. Further, 0.15 parts by weight (solid component ratio) of a cross-linking agent (epoxy-based cross-linking agent, Tetrad C, manufactured by Mitsubishi Gas Chemical Co., Ltd.) was added to prepare an adhesive solution for a pressure-sensitive adhesive layer.

Table 1 shows the thickness of the pressure-sensitive adhesive layer after drying on a release-treated PET film (manufactured by Toyo Cloth Co., Ltd., SP3000-75) of the obtained pressure-sensitive adhesive layer adhesive solution. After coating so as to have a thickness, it was dried at 110° C. for 5 minutes to form a pressure-sensitive adhesive layer. This pressure-sensitive adhesive layer was transferred to an electrolytic copper foil (thickness: 18 μm, manufactured by Fukuda Metal Foil Powder Co., Ltd.) as a base material, and the release-treated PET film was peeled off. Then, the adhesive solution for the heat-sensitive adhesive layer is applied onto a 75 μm-thick release-treated PET film (manufactured by Toyo Cloth Co., Ltd., SP3000-75), and the thickness of the heat-sensitive adhesive layer after drying becomes the thickness shown in Table 1. and dried at 110° C. for 5 minutes to form a heat-sensitive adhesive layer. This heat-sensitive adhesive layer was transferred to the pressure-sensitive adhesive layer at 23° C. and cured at 40° C. for 48 hours to obtain the substrate, pressure-sensitive adhesive layer, heat-sensitive adhesive layer, and release-treated PET film. A single-sided adhesive tape laminated in this order was obtained.

(3) Measurement of gel fraction Measurement was carried out in the same manner as in Example 1.

(4) Measurement of storage elastic modulus G' and loss tangent peak temperature Measurements were carried out in the same manner as in Example 1.

(5) Measurement of Static Friction Coefficient Measurement was carried out in the same manner as in Example 1.

(6) Measurement of surface roughness Ra Measurement was performed in the same manner as in Example 1.

(Examples 5-14, Comparative Examples 2-3)
A single-sided adhesive tape was obtained in the same manner as in Example 1, except for the changes shown in the table.
In Example 5, the PET film (manufactured by Toyo Cloth Co., Ltd., type 10) was used instead of the release-treated PET film on which the adhesive solution for the heat-sensitive adhesive layer was applied. Changed Ra.

<Evaluation>
The single-sided pressure-sensitive adhesive tapes obtained in Examples and Comparative Examples were evaluated as follows. The results are shown in Tables 1-3.

(1) Evaluation of wrinkles during application The obtained single-sided adhesive tape was cut into 7 mm × 80 mm, and the edge of a copper clad laminate (CCL) (manufactured by Panasonic, R1515E, resin layer thickness 40 μm, copper foil thickness 2 μm) pasted on the part.
More specifically, a single-sided pressure-sensitive adhesive tape was attached so as to form the covering form shown in FIG. First, a single-sided adhesive tape was placed on one side of one side of the copper-clad laminate so that the end of the long side of the single-sided adhesive tape was positioned 3.5 mm from the edge of the copper-clad laminate. It was heat-pressed for 30 seconds at a pressure of 0.3 MPa. After that, while pressing the base surface of the single-sided adhesive tape that is not attached with a stainless steel plate, the single-sided adhesive tape is bent toward the other side of the copper-clad laminate so as not to create a gap, and the copper-clad laminate is attached. It was brought into contact with the other surface and heat-pressed under the condition of 100° C. and the pressure of 0.3 MPa for 30 seconds.
The attached single-sided adhesive tape was visually observed to confirm the occurrence of wrinkles. The case where there was no wrinkle was evaluated as ◯, and the case where there was wrinkle was evaluated as X.

(2) Evaluation of resistance to strong alkaline solution In the same manner as in "(1) Evaluation of wrinkles during application" above, a single-sided adhesive tape was attached to the end of the copper-clad laminate to prepare a test piece, The following evaluations were performed. Table 4 shows the conditions for electroless plating, and Table 5 shows the conditions for desmear treatment.

(2-1) Strong alkaline solution A sodium hydroxide aqueous solution adjusted to 5% by weight was heated to 50° C., and the test piece was immersed for 5 minutes. After taking out the test piece, the single-sided adhesive tape was peeled off from the copper-clad laminate. The resistance to strong alkaline solutions was evaluated by confirming discoloration of the copper at the portion of the copper-clad laminate where the single-sided adhesive tape had been pasted.
◎ indicates no discoloration of the copper, ◯ indicates discoloration of the copper within 2 mm from the end of the portion where the single-sided adhesive tape was applied, and ◯ indicates the portion where the single-sided adhesive tape was applied. The case where discoloration of copper was observed in a range exceeding 2 mm from the edge of the plate was evaluated as x.

(2-2) Desmear and Electroless Plating Test pieces were subjected to desmear treatment under the conditions shown in Table 5, and then electrolessly plated under the conditions shown in Table 4. After taking out the test piece, the single-sided adhesive tape was peeled off from the copper-clad laminate. Resistance to desmear and electroless plating was evaluated by confirming discoloration of copper in the portion of the copper-clad laminate where the single-sided adhesive tape had been pasted.
◎ indicates no discoloration of the copper, ◯ indicates discoloration of the copper within 2 mm from the end of the portion where the single-sided adhesive tape was applied, and ◯ indicates the portion where the single-sided adhesive tape was applied. The case where discoloration of copper was observed in a range exceeding 2 mm from the edge of the plate was evaluated as x.

BA: butyl acrylate 2-EHA: 2-ethylhexyl acrylate MMA: methyl methacrylate BMA: butyl methacrylate IBOA: isobornyl acrylate IBOMA: isobornyl methacrylate AAc: acrylic acid HEA: 2-hydroxyethyl acrylate

1 edge-protected metal-clad laminate 2 metal-clad laminate 30, 30', 30'' single-sided adhesive tape 31, 31', 31'' substrate 32, 32', 32'' heat-sensitive adhesive layer 3a heat-sensitive Interface between adhesive layers

Claims

A single-sided adhesive tape having a substrate and a heat-sensitive adhesive layer laminated on one side of the substrate,
The base material has a metal layer at least on the surface opposite to the heat-sensitive adhesive layer,
The single-sided adhesive tape, wherein the heat-sensitive adhesive layer has a static friction coefficient of 5 or less against SUS.
2. The single-sided adhesive tape of claim 1, wherein said metal layer is made of copper.
3. The single-sided pressure-sensitive adhesive tape according to claim 1, wherein said base material is a metal base material.
4. The single-sided adhesive tape according to claim 3, wherein said metal substrate is a copper foil.
5. The single-sided adhesive tape according to claim 1, further comprising a pressure-sensitive adhesive layer between said substrate and said heat-sensitive adhesive layer.
6. The heat-sensitive adhesive layer according to claim 1, wherein the peak temperature of loss tangent measured at a measurement frequency of 1 Hz using a dynamic viscoelasticity measuring device is 40° C. or higher. single-sided adhesive tape.
6. The heat-sensitive adhesive layer has a storage modulus G' of 5 MPa or more at 23° C. and a storage modulus G' of 0.2 MPa or less at 100° C. Or the single-sided adhesive tape according to 6.
8. The single-sided adhesive tape according to claim 1, 2, 3, 4, 5, 6 or 7, wherein said heat-sensitive adhesive layer has a gel fraction of 50% by weight or more.
9. The single-sided adhesive tape according to claim 1, wherein the heat-sensitive adhesive layer has a surface roughness Ra of 0.01 μm or more and 0.8 μm or less. .
10. The single-sided pressure-sensitive adhesive tape according to claim 1, wherein said heat-sensitive pressure-sensitive adhesive layer contains an acrylic polymer.
11. The single-sided adhesive tape according to claim 10, wherein said heat-sensitive adhesive layer further contains a tackifying resin.
12. The single-sided pressure-sensitive adhesive tape according to claim 11, wherein said tackifying resin has a softening point of 100[deg.] C. or higher.
13. The single-sided pressure-sensitive adhesive tape according to claim 11, wherein the tackifying resin has a hydroxyl value of 25 mgKOH/g or more.
14. The single-sided pressure-sensitive adhesive tape according to claim 11, 12 or 13, wherein the content of said tackifier resin is 5 parts by weight or more and 50 parts by weight or less with respect to 100 parts by weight of said acrylic polymer.
15. The single-sided adhesive tape according to claim 10, 11, 12, 13 or 14, wherein the heat-sensitive adhesive layer contains an epoxy-based cross-linking agent.
6. The single-sided adhesive tape according to claim 5, wherein the pressure-sensitive adhesive layer has a gel fraction of 50% by weight or more.
6. The single-sided adhesive tape according to claim 5, wherein the pressure-sensitive adhesive layer contains an epoxy-based cross-linking agent.
A single-sided adhesive tape having a substrate and a heat-sensitive adhesive layer laminated on one side of the substrate,
The base material has a metal layer at least on the surface opposite to the heat-sensitive adhesive layer,
The heat-sensitive adhesive layer contains an acrylic polymer and a tackifying resin,
The tackifying resin has a softening point of 100° C. or higher and a hydroxyl value of 25 mgKOH/g or higher,
The content of the tackifying resin with respect to 100 parts by weight of the acrylic polymer is 5 parts by weight or more and 50 parts by weight or less,
The single-sided adhesive tape, wherein the heat-sensitive adhesive layer has a static friction coefficient of 5 or less against SUS.
Claims 1 and 2, characterized in that it is used to protect the edge of the metal-clad laminate by attaching it to the edge of the metal-clad laminate in the etching process, the desmear process, or the electroless plating process. 19. The single-sided adhesive tape according to 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 or 18.
A single-sided adhesive tape having a metal layer on one side and a heat-sensitive adhesive layer on the other side,
The single-sided adhesive tape, wherein the heat-sensitive adhesive layer has a static friction coefficient of 5 or less against SUS.