CN114286847A

CN114286847A - Heat-sensitive adhesive sheet and method for manufacturing article to which heat-sensitive adhesive sheet is bonded

Info

Publication number: CN114286847A
Application number: CN202080059699.2A
Authority: CN
Inventors: 下冈澄生; 森野彰规
Original assignee: DIC Corp
Current assignee: DIC Corp
Priority date: 2019-09-10
Filing date: 2020-08-27
Publication date: 2022-04-05
Also published as: JP7111260B2; JPWO2021049301A1; WO2021049301A1

Abstract

The invention provides an adhesive sheet and a method for manufacturing an article using the same, which can inhibit bubble formation caused by gas which can be generated by a thermoplastic bonding material and the like and peeling caused by curved surface springback of the thermoplastic bonding material and the like when the thermoplastic bonding material and the like are heated and deformed along the surface of a formed object and the like and are bonded, and can simultaneously achieve excellent reworkability and peeling resistance in the initial stage of bonding. The present invention relates to a heat-sensitive adhesive sheet and the like, the heat-sensitive adhesive sheet having a heat-sensitive adhesive layer (a) having a temperature of-50 ℃ to 200 DEG CHas at least one or more peak temperatures of tensile loss tangent (tan delta) measured at a frequency of 3Hz at 90 ℃ or higher and at least one or more peak temperatures of-20 ℃ or lower, and has a tensile storage modulus (E ') at 100℃'_a100) Is 5 x 10⁵Pa～1×10⁸Pa, the heat-sensitive adhesive sheet is used for bonding the thermoplastic bonding material (B) to the surface of the molded article (C) with the heat-sensitive adhesive layer as an adhesive layer.

Description

Heat-sensitive adhesive sheet and method for manufacturing article to which heat-sensitive adhesive sheet is bonded

Technical Field

The present invention relates to a heat-sensitive adhesive sheet and a method for manufacturing an article to which the heat-sensitive adhesive sheet is bonded.

Background

In order to impart design properties and functionality to the surface of a molded product, a decorative layer (hereinafter, referred to as a "decorative layer") colored by a colored paint, metal vapor deposition, or the like, or a functional layer (hereinafter, referred to as a "functional layer") including metal wiring such as a touch sensor element, an antenna, or the like is laminated on the surface of a molded product such as an interior or exterior part of a home appliance, a mobile terminal, an automobile, or the like. In order to protect the surface of the decorative layer or the functional layer from scratches, deterioration, corrosion, and the like, a thermoplastic bonding material made of polycarbonate resin, acrylic resin, or the like is bonded to the surface layer of the decorative layer or the functional layer. Further, a hard coat layer, a matte layer, an ultraviolet absorbing layer, an antistatic layer, and the like may be laminated on the surface of the thermoplastic bonding material, and these layers can more effectively protect the decorative layer and the functional layer from scratches, ultraviolet deterioration, disconnection due to charge discharge, and the like. Further, if the decorative layer and the functional layer are laminated on the back surface side of the thermoplastic laminating material in advance and then laminated on the surface of the molded product, the lamination can be performed more easily than in the case where they are directly laminated on the surface of the molded product.

As a method for bonding a thermoplastic bonding material to a molded product, for example, a bonding method using a compressed air molding machine, a vacuum molding machine, a TOM molding machine, or the like, in which the thermoplastic bonding material is heated to 90 to 200 ℃ for 1 to 300 seconds to soften the thermoplastic bonding material and is strongly pressed by compressed air or the like to the surface of the molded product provided in a reduced pressure space, thereby causing the heated thermoplastic bonding material to adhere and fix along the shape of the surface of the molded product while deforming in the three-dimensional direction, can be used (for example, patent document 1).

However, in the method of heating the thermoplastic bonding material to a temperature higher than the temperature at which tackiness occurs and bonding the thermoplastic bonding material to the surface of the molded product, the surface of the thermoplastic bonding material is also softened, and appearance defects such as uneven gloss and waviness are easily caused. Therefore, a method is used in which an adhesive layer is sandwiched between a thermoplastic bonding material and a molded product, and the heating temperature at the time of molding the thermoplastic bonding material is reduced.

As the adhesive layer, for example, a liquid adhesive that undergoes a curing reaction by excitation energy such as heat, moisture, or ultraviolet rays is used (for example, patent document 2). However, when a liquid adhesive that cures by heat or moisture is used, a curing time of about 24 hours is required from the time when the thermoplastic bonding material is bonded to the surface of the molded product to the time when the thermoplastic bonding material cures. In addition, when a liquid adhesive that is cured by ultraviolet rays is used, light transmission is blocked by a shielding material such as a decorative layer on the back surface of the thermoplastic bonding material, an ultraviolet absorbing layer, or the like, and ultraviolet curing is blocked, which tends to cause insufficient curing. Therefore, there are problems as follows: during the period until the liquid adhesive is solidified and the thermoplastic bonding material is fixed, the thermoplastic bonding material deformed in the three-dimensional direction is floated or peeled from the end due to the resilience of the curved surface, or the liquid adhesive flows and is extruded, or the thickness of the adhesive layer is likely to change. Further, if the liquid adhesive is heated to about 90 to 200 ℃ in a state of being laminated with the thermoplastic bonding material, there is a problem that the liquid adhesive is likely to form bubbles due to gas generated from the thermoplastic bonding material by heating.

In addition, a thermosetting or ultraviolet-curable adhesive sheet containing a polymerizable monomer or oligomer component may be used without using a liquid adhesive. These adhesive sheets are less likely to suffer from extrusion from the adherend and thickness change due to floating, peeling, and flowing from the end portions as in the liquid adhesive, but have a problem that, similarly to the liquid adhesive, when heated to a temperature of about 90 to 200 ℃ in a state of being laminated with a thermoplastic adhesive material, the polymerizable monomer or oligomer component significantly softens the adhesive layer, and the adhesive sheet is likely to form bubbles due to gas generated from the thermoplastic adhesive material.

However, when at least one of the thermoplastic bonding material and the molded product generates gas when it is left to stand for a long period of time in a high-temperature and high-humidity environment such as 85 ℃ and 85% RH, the pressure of the generated gas changes the adhesive layer with time, and the adhesive sheet is likely to form bubbles or peel off.

In the case where grooves for releasing gas generated from the thermoplastic bonding material or the molded product from the interface of the adhesive layer to the periphery are provided (for example, patent document 3), or minute pores are provided on the surface of the thermoplastic bonding material, these grooves and pores remain even after the heat bonding, and the appearance is not good. In addition, in order to suppress the generation of gas from the surface of the thermoplastic bonding material or the molded product after the bonding, a step of heating the bonding material in advance to release the gas is required (for example, patent document 4), and the production efficiency is not good.

In addition, when the liquid adhesive or the adhesive sheet is used, there are problems as follows: since it is easily tacky at room temperature, when it is mounted on a bonding apparatus such as a compressed air molding machine, a vacuum molding machine, or a TOM molding machine, it is difficult to correct the position, or dirt or foreign matter adheres to the surface of the adhesive, and the appearance after bonding is impaired. Further, when the thermoplastic bonding material is molded in accordance with the shape of the molded product and then bonded to the surface of the molded product with the liquid adhesive or the adhesive sheet, there are also problems as follows: since the adhesive tends to be tacky at room temperature, the bonding position shifts, or bubbles are mixed in the bonding interface.

The above problems can be solved by using a hot-melt heat-sensitive adhesive or a heat-sensitive adhesive sheet which does not contain a polymerizable monomer or oligomer component, is solid at a temperature of less than 90 ℃ and does not cause stickiness, and softens at 90 to 200 ℃, but because of lack of flexibility in a low-temperature environment, the adhesive layer cannot completely alleviate strain caused by a difference in expansion between the thermoplastic bonding material and the molded product when used in a cold environment of 0 ℃ or less such as an automobile or in applications where cooling and heating are repeated such as a home electric appliance and a mobile terminal, and the like, and the problem is that the adhesive layer is likely to float or peel between the thermoplastic bonding material and the molded product.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2015-145103

Patent document 2: japanese patent laid-open publication No. 2015-072343

Patent document 3: japanese patent laid-open publication No. 2011-016258

Patent document 4: japanese patent laid-open No. 2014-205335

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a heat-sensitive adhesive sheet and a method for manufacturing an article using the heat-sensitive adhesive sheet, which can realize bonding of a thermoplastic bonding material or the like to a molded article or the like by heating the thermoplastic bonding material or the like to a temperature of 90 to 200 ℃ and deforming the same in a three-dimensional direction along the surface of the molded article or the like, can suppress bubble formation due to gas that can be generated from the thermoplastic bonding material or the like, and peeling due to curved surface springback of the thermoplastic bonding material or the like, can realize bonding of the thermoplastic bonding material or the like to the molded article or the like, can suppress bubble formation and peeling due to gas that can be generated from at least one of the thermoplastic bonding material or the molded article or the like even when the bonded article is left in a high-temperature and high-humidity environment, and can suppress floating between the thermoplastic bonding material or the like and the molded article or the like even when the bonded article or the bonded article is used in a cold environment or repeatedly cooled and heated, And (6) stripping.

Means for solving the problems

The present inventors have found that the above problems can be solved by a heat-sensitive adhesive sheet including a heat-sensitive adhesive layer having various tensile elastic moduli and a bonding method using the heat-sensitive adhesive sheet.

That is, the present invention provides a heat-sensitive adhesive sheet (a) having a heat-sensitive adhesive layer (a) which has a peak temperature of tensile loss tangent (tan δ) measured at a frequency of 3Hz in the range of-50 ℃ to 200 ℃ of at least one or more at 90 ℃ or higher and at least one or more at-20 ℃ or lower, and a tensile storage modulus (E'_a100) Is 5 x 10⁵Pa～1×10⁸Pa, the heat-sensitive adhesive sheet (a) is used for bonding the thermoplastic bonding material (B) to the surface of the molded article (C) with the heat-sensitive adhesive layer as an adhesive layer.

Effects of the invention

The heat-sensitive adhesive sheet of the present invention uses a specific heat-sensitive adhesive sheet as an adhesive layer for adhering a thermoplastic adhesive material or the like to a molded product or the like, and thus can realize adhesion of the thermoplastic adhesive material or the like to the molded product or the like while suppressing bubble formation due to gas that can be generated from the thermoplastic adhesive material or the like and peeling due to curved surface springback of the thermoplastic adhesive material or the like in a step of adhering the thermoplastic adhesive material or the like to the molded product or the like while heating the thermoplastic adhesive material or the like to a temperature of about 90 to 200 ℃ and deforming the thermoplastic adhesive material or the like in a three-dimensional direction along the surface or the like of the molded product. Further, the heat-sensitive adhesive sheet of the present invention can suppress bubble formation and peeling caused by gas that can be generated from at least one of the thermoplastic bonding material and the molded product even when the bonded product of the thermoplastic bonding material and the molded product and the like is left in a high-temperature and high-humidity environment, and can realize a bonded product of the molded product and the like and the thermoplastic bonding material and the like that suppress floating and peeling between the thermoplastic bonding material and the molded product and the like even when used in a cold environment or repeatedly cooled and heated. Therefore, the heat-sensitive adhesive sheet of the present invention and the method for producing an article using the same can contribute greatly to the production of resin molded articles used for exterior decoration of home electric appliances, exterior decoration of mobile terminals, interior and exterior decoration of automobiles, and the like.

Drawings

FIG. 1 is a diagram showing an example of a micro-domain of a band-like structure (layer).

FIG. 2 is a diagram showing an example of a band-shaped (cylindrical) micro domain.

FIG. 3 is a video image showing an example of a micro-domain having a non-band structure.

Detailed Description

The heat-sensitive adhesive sheet (A) is provided with a heat-sensitive adhesive layer (a), wherein the peak temperature of the tensile loss tangent (tan delta) of the heat-sensitive adhesive layer (a) measured in the range of-50 ℃ to 200 ℃ and at the frequency of 3Hz is more than or equal to 90 ℃ and less than or equal to-20 ℃, and the tensile storage modulus (E ') at 100 DEG is more than or equal to'_a100) Is 5 x 10⁵Pa～1×10⁸Pa in which the thermoplastic bonding material (B) is bonded to the surface of the molded article (C) using the thermosensitive adhesive layer as an adhesive layer.

According to the heat-sensitive adhesive sheet, when the thermoplastic bonding material (B) is heated and bonded while being deformed in a three-dimensional direction along the surface of the molded article (C), the heat-sensitive adhesive sheet (a) having the heat-sensitive adhesive layer (a) can suppress bubble formation due to gas generation from the thermoplastic bonding material (B) and peeling due to curved surface springback of the thermoplastic bonding material (B), and can obtain a bonded article without impairing the appearance.

Further, according to the heat-sensitive adhesive sheet, the thermoplastic bonding material (B) and the molded product (C) are bonded by the heat-sensitive adhesive sheet (a) having the heat-sensitive adhesive layer (a), so that even when the adhesive is left in a high-temperature and high-humidity environment, bubble formation and peeling caused by gas that can be generated from at least one of the thermoplastic bonding material (B) and the molded product (C) can be suppressed, and even when the adhesive is left in a cold environment or repeatedly cooled and heated, floating and peeling between the thermoplastic bonding material and the molded product can be suppressed.

Further, the heat-sensitive adhesive sheet of the present invention has predetermined physical properties in addition to the above-described effects, and therefore has low adhesion at room temperature, and therefore, dust is not easily attached thereto, and reattachment can be easily performed. In addition, the heat-sensitive adhesive sheet of the present invention has low adhesiveness at room temperature, and therefore can be suitably used for bonding the molded thermoplastic bonding material (B) and the molded product (C). Specifically, when the thermoplastic bonding material (B) is molded in advance in accordance with the shape of the molded article (C) and the molded thermoplastic bonding material (B) and the molded article (C) are joined by fitting them together via an adhesive sheet, if the adhesiveness of the adhesive sheet at room temperature is high, the molded thermoplastic bonding material (B) may not be easily fitted together via the adhesive sheet, and thus may not be sufficiently joined. In contrast, according to the heat-sensitive adhesive sheet of the present invention, since the room-temperature adhesiveness is low, the molded members can be sufficiently fitted and joined to each other.

The heat-sensitive adhesive layer (a) and the heat-sensitive adhesive sheet (a) are defined as follows: the thermoplastic adhesive material (B) or the molded article (C) has an adhesive strength of 5N/cm or more at a temperature of 23 ℃ and a relative humidity of 50% RH by heating at 90 to 200 ℃ for about 1 to 300 seconds immediately after the application of the thermoplastic adhesive material (B) or the molded article (C).

As the heat-sensitive adhesive sheet (a), a heat-sensitive adhesive sheet composed of a single layer or 2 or more layers of heat-sensitive adhesive layer (a) can be used.

1. Heat-sensitive adhesive sheet (A)

The heat-sensitive adhesive sheet (A) of the present invention uses, as the adhesive layer, a heat-sensitive adhesive sheet having a tensile storage modulus (E'_a100) Is 5 x 10⁵Pa～1×10⁸Pa, a heat-sensitive adhesive layer (a). By using the thermosensitive adhesive layer (a) as the adhesive layer of the thermosensitive adhesive sheet (a), when the thermoplastic adhesive sheet (B) is heated to 90 to 200 ℃ and adhered to the surface of the molded article (C), thermosensitive adhesion can be performed by the thermosensitive adhesive layer (a) constituting the thermosensitive adhesive sheet (a), and bubble formation due to gas that can be generated by the thermoplastic adhesive sheet (B) and peeling due to curved surface springback of the thermoplastic adhesive sheet (B) can be suppressed, and a sticker can be obtained without impairing the appearance. Further, the heat-sensitive adhesive layer (a) is placed on the high-temperature and high-humidity ring even when the adhesive is placed on the high-temperature and high-humidity ringThe formation of bubbles due to gas that can be generated by at least one of the thermoplastic bonding material (B) and the molded product (C) can be suppressed even in an ambient environment, a cold environment, or a hot and cold environment, and peeling due to strain caused by a difference in thermal expansion can be suppressed. In this way, the heat-sensitive adhesive layer (a) becomes an adhesive layer of the heat-sensitive adhesive sheet (a) having both appropriate hardness and adhesive strength.

The peak temperature having at least one loss tangent at 90 ℃ or higher is preferably in the range of 100 to 150 ℃, more preferably in the range of 110 to 140 ℃, and particularly preferably in the range of 110 to 130 ℃. By having the peak temperature in the above temperature range, when the thermoplastic bonding material (B) is heated to a suitable softened state for deformation in the three-dimensional direction and bonded, the thermosensitive adhesive layer (a) can obtain suitable flexibility to enable thermosensitive bonding, and can suppress bubble formation due to gas that can be generated from the thermoplastic bonding material (B) and peeling due to curved surface springback of the thermoplastic bonding material (B).

The peak temperature having at least one loss tangent at-20 ℃ or lower is preferably in the range of-60 ℃ to-20 ℃, more preferably in the range of-50 ℃ to-25 ℃, and particularly preferably in the range of-40 ℃ to-25 ℃. By having the peak temperature in the above temperature range, even when the bonded product of the thermoplastic bonding material (B) and the molded product (C) is used in a cold environment or repeatedly cooled and heated, the thermosensitive adhesive layer (a) can maintain appropriate flexibility, and the thermosensitive adhesive layer (a) constituting the thermosensitive adhesive sheet (a) can alleviate strain caused by a difference in thermal expansion between the thermoplastic bonding material (B) and the molded product (C), and suppress floating and peeling between the thermoplastic bonding material (B) and the molded product (C).

Further, the tensile storage modulus (E ') at 100 ℃ as described above'_a100) Preferably 1X 10⁶Pa～7×10⁷Pa, more preferably 3X 10⁶Pa～5×10⁷Pa, particularly preferably 3X 10⁶Pa～3×10⁷Pa. By using the heat-sensitive adhesive layer (a) having a tensile storage modulus in the above range, the thermoplastic bonding material (B) is heated at 90 to 200 ℃ for 1 to 300 secondsTo the extent of being bonded to the molded article (C), a thermosensitive adhesive layer having both appropriate hardness and adhesiveness can be formed, and the formation of bubbles due to gas that can be generated from the thermoplastic bonding material (B) and the peeling due to the curved surface springback of the thermoplastic bonding material (B) can be suppressed. Further, even when the above-mentioned adhesive sheet is left in a high-temperature and high-humidity environment, a cold environment, or a cold and hot environment, the adhesive layer of the heat-sensitive adhesive sheet (a) having both appropriate hardness and adhesive strength is formed, which can suppress bubble formation and peeling.

The loss tangent (tan δ) of the heat-sensitive adhesive layer (a) at a peak temperature of 90 ℃ or higher is preferably 2.0 or less, more preferably 1.5 or less, and is particularly preferably in the range of 0.3 to 1.0, from the viewpoint that when the thermoplastic bonding material (B) is heated to an appropriate softened state and bonded, the heat-sensitive adhesive layer (a) attains appropriate flexibility to perform heat-sensitive bonding, and bubble formation due to gas that can be generated from the thermoplastic bonding material (B) and peeling due to curved surface springback of the thermoplastic bonding material (B) are suppressed.

The loss tangent (tan δ) of the heat-sensitive adhesive layer (a) at a peak temperature of-20 ℃ or lower is preferably 2.0 or lower, more preferably 1.5 or lower, and is particularly preferably in the range of 0.3 to 1.0, from the viewpoint that a bonded product bonded with the heat-sensitive adhesive sheet (a) composed of the heat-sensitive adhesive layer (a) maintains suitable hardness and adhesive strength capable of suppressing peeling due to strain caused by a difference in thermal expansion between the thermoplastic bonding material (B) and the molded product (C) in a low-temperature environment even when the bonded product is left in a cold environment or a cold and hot environment.

Tensile storage modulus (E ') at-20 ℃ of the thermosensitive adhesive layer (a)'_a-20) Preferably 5X 10⁶Pa～3×10⁹Pa, more preferably 1X 10⁷Pa～9×10⁸Pa is preferably 3 × 10, in particular, from the viewpoint that the thermosensitive adhesive layer (a) relaxes strain caused by a difference in thermal expansion between the thermoplastic bonding material (B) and the molded product (C) and suppresses floating and peeling between the thermoplastic bonding material (B) and the molded product (C) when the bonded product of the thermoplastic bonding material (B) and the molded product (C) is used in a cold environment or is repeatedly cooled and heated⁷Pa～7×10⁸Pa。

Tensile storage modulus (E ') at 25 ℃ of the thermosensitive adhesive layer (a)'_a25) Preferably 1X 10⁶Pa～1×10⁹Pa, more preferably 5X 10⁶Pa～7×10⁸Pa is more preferably 1 × 10, because it is easy to perform position correction when the thermoplastic bonding material is mounted on a compressed air molding machine, a vacuum molding machine, a TOM molding machine, or the like at room temperature, and it is also possible to suppress the floating and peeling of the bonded product of the thermoplastic bonding material (B) and the molded product (C) when the bonded product is suddenly left at room temperature in a cold environment or repeatedly cooled and heated⁷Pa～5×10⁸Pa。

Further, the thermal sensitive adhesive layer (a) has a tensile storage modulus (E ') at 150 ℃'_a150) Preferably 1X 10⁵Pa～1×10⁷Pa, more preferably 1X 10⁵Pa～7×10⁶Pa is particularly preferably 1 × 10 in order to form a heat-sensitive adhesive layer having both appropriate hardness and adhesiveness when the thermoplastic bonding material (B) is heated at 90 to 200 ℃ for about 1 to 300 seconds and bonded to the molding (C), and to suppress bubble formation due to gas that can be generated from the thermoplastic bonding material (B) and peeling due to curved surface springback of the thermoplastic bonding material (B)⁵Pa～5×10⁶Pa。

The tensile storage modulus and the loss tangent (tan. delta.) were measured in a tensile mode using a viscoelasticity tester (product of TA instruments Japan, trade name: RSA III) under conditions of a vibration number of 3.0Hz and a temperature rise rate of 5 ℃/min in a temperature range of-50 ℃ to 200 ℃. The test piece used for the measurement was a rectangular test piece obtained by laminating the heat-sensitive adhesive layer (a) to 400 to 600 μm, making the width of the test piece 5mm, making the length of the measurement portion 20mm, and cutting the handles at both ends to 20mm each.

[ Heat-sensitive adhesive layer (a) ]

The thermosensitive adhesive layer (a) is formed of an adhesive composition, and can be produced, for example, by applying a solution of an adhesive composition obtained by dissolving the adhesive composition described later in an organic solvent or the like to the surface of a release liner or the like, and drying the solution.

The adhesive composition is not particularly limited as long as the adhesive composition can have the physical properties, and for example, an adhesive composition containing a block copolymer comprising a polymer block having a glass transition temperature of-20 ℃ or lower (S1) and a polymer block having a glass transition temperature of 90 ℃ or higher (S2) is preferably used. More specifically, compounds containing the formula: triblock copolymers such as (meth) acrylic triblock copolymers and vinyl aromatic triblock copolymers (triblock copolymers composed of an aromatic vinyl monomer and a conjugated diene monomer) represented by S2 to S1 to S2, or triblock copolymers represented by the formula: and diblock copolymers such as (meth) acrylic diblock copolymers represented by S1 to S2, and vinyl aromatic diblock copolymers (diblock copolymers composed of an aromatic vinyl monomer and a conjugated diene monomer). Among them, from the viewpoint of suppressing bubble formation and peeling, it is preferable to use a composition containing the formula: an adhesive composition of a triblock copolymer represented by S2-S1-S2.

By using the above block copolymer, the polymer blocks (S1) and the polymer blocks (S2) form domains with each other. By forming the domains, when the heat-sensitive adhesive sheet (a) is used as an adhesive layer and the thermoplastic adhesive material (B) is heated and adhered while deforming one edge thereof in a three-dimensional direction along the surface of the molded article (C), the domains of the polymer block (S2) having a glass transition temperature of 90 ℃ or higher contained in the heat-sensitive adhesive layer (a) suppress bubble formation due to gas that can be generated from the thermoplastic adhesive material (B) and peeling due to curved surface springback of the thermoplastic adhesive material (B), and even when the adhesive is left in a high-temperature and high-humidity environment, bubble formation and peeling due to gas that can be generated from at least one of the thermoplastic adhesive material (B) and the molded article (C) are suppressed. On the other hand, the domains of the polymer block (S1) having a glass transition temperature of-20 ℃ or lower contained in the thermosensitive adhesive layer (a) improve the thermosensitive adhesiveness when the thermoplastic bonding material (B) is bonded to the molded article (C) by heating at 90 to 200 ℃ for about 1 to 300 seconds, and also alleviate the strain caused by the difference in thermal expansion between the thermoplastic bonding material (B) and the molded article (C) when the above-mentioned bonded article is used in a cold environment or repeatedly heated and cooled, thereby suppressing the floating and peeling between the thermoplastic bonding material (B) and the molded article (C).

The glass transition temperatures of the polymer block (S1) and the polymer block (S2) of the block copolymer are extrapolated onset temperatures of transition regions of the polymer block (S1) and the polymer block (S2) in a curve obtained by analyzing the copolymer resin with a Differential Scanning Calorimeter (DSC).

When the (meth) acrylic block copolymer is used as the copolymer contained in the adhesive composition, examples of the polymer block having a glass transition temperature of 90 ℃ or higher (S2) constituting the (meth) acrylic block copolymer include methacrylic acid esters such as methyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, and phenyl methacrylate; and a polymer block composed of an acrylate such as isobornyl acrylate. These may be used alone or in combination of 2 or more to form a polymer block (S2). Among them, the polymer block is more preferably formed using methyl methacrylate because the adjustment is easy to the above-mentioned predetermined viscoelastic range, the formation of bubbles and the peeling due to the springback of the curved surface of the thermoplastic bonding material (B) are suppressed, the formation and the peeling of bubbles are easily suppressed even when the above-mentioned bonded product is left in a high-temperature and high-humidity environment, and the moldability and the heat-sensitive adhesiveness of the heat-sensitive adhesive layer (a) are excellent (S2).

Examples of the polymer block (S1) having a glass transition temperature of-20 ℃ or higher, which constitutes the (meth) acrylic block copolymer, include methacrylic acid esters such as n-lauryl methacrylate, pentadecyl methacrylate, dodecyl methacrylate, stearyl methacrylate, and 2-ethoxyethyl methacrylate; and (3) a polymer block of an acrylic ester such as ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, pentyl acrylate, isopentyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, pentadecyl acrylate, dodecyl acrylate, and 2-methoxyethyl acrylate. These may be used alone or in combination of 2 or more to form a polymer block (S1). Among them, from the viewpoint of ease of adjustment to the above-mentioned predetermined viscoelastic range, ease of relaxation of strain due to a difference in thermal expansion when the adhesive composition is used in a cold environment or repeatedly cooled and heated, and excellent heat-sensitive adhesiveness of the heat-sensitive adhesive layer (a), it is preferable to form the polymer block using any one of ethyl acrylate, isopropyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate (S1).

The glass transition point can be determined by any method, and a method according to the plastic transition temperature measurement method by the differential thermal analysis method or the differential scanning calorimetry method (JIS K7121-1987) is preferably used.

The glass transition temperature of the polymer block (S2) is preferably in the range of 90 to 150 ℃, more preferably 100 to 130 ℃, and most preferably 100 to 120 ℃ in order to suppress bubble formation due to gas that can be generated from the thermoplastic bonding material (B) and peeling due to curved surface springback of the thermoplastic bonding material (B), and to suppress bubble formation and peeling due to gas that can be generated from at least one of the thermoplastic bonding material (B) and the molded article (C) even when the adhesive is left in a high-temperature and high-humidity environment.

The glass transition temperature of the polymer block (S1) is preferably in the range of-90 ℃ to-20 ℃, more preferably-70 ℃ to-30 ℃, and is most preferably-60 ℃ to-40 ℃ in order to improve the heat-sensitive adhesiveness when the thermoplastic bonding material (B) is bonded to the molded article (C) by heating at 90 ℃ to 200 ℃ for 1 second to 300 seconds, to alleviate the strain caused by the difference in thermal expansion between the thermoplastic bonding material (B) and the molded article (C) when the bonding material is used in a cold environment or repeatedly cooled and heated, and to suppress the floating and peeling between the thermoplastic bonding material (B) and the molded article (C).

The (meth) acrylic block copolymer may have other polymer blocks in addition to the polymer blocks (S1) and (S2). Examples of the other polymer block include polymer blocks composed of monomer units such as methacrylic acid, acrylic acid, methacrylonitrile, acrylonitrile, vinyl acetate, styrene, α -methylstyrene, p-methylstyrene, m-methylstyrene, ethylene, propylene, butadiene, isobutylene, isoprene, octene, maleic anhydride, vinyl chloride, vinylidene chloride, and hydrogenated products thereof; and polymer blocks composed of polyethylene terephthalate, polybutylene terephthalate, polylactic acid, polyurethane, polydimethylsiloxane, and the like. These may be used alone or in combination of 2 or more to form a polymer block. In the case where the heat-sensitive adhesive layer (a) is in contact with a decorative layer formed by metal deposition or a functional layer with metal wiring or the like, it is preferable that the (meth) acrylic block copolymer does not contain a polymer block formed from an acid group-containing monomer such as methacrylic acid or acrylic acid in order to prevent corrosion or discoloration of the metal layer.

The (meth) acrylic block copolymer may have a crosslinkable functional group and be crosslinked with a crosslinking agent to improve cohesive force. Examples of the crosslinkable functional group include a hydroxyl group, a carboxyl group, and a glycidyl group, and in the case of having a hydroxyl group, a crosslinking agent such as a polyfunctional isocyanate compound can be used, in the case of having a carboxyl group, a crosslinking agent such as a polyfunctional epoxy compound can be used, and in the case of having a glycidyl group, a crosslinking agent such as an amine compound, an acid anhydride, and a polyfunctional thiol can be used. The content of the crosslinkable functional group is preferably 1,000 to 100,000 equivalents, and from the viewpoint of achieving the above-mentioned suitable viscoelastic range, it is preferably 3,000 to 50,000 equivalents, and particularly preferably 5,000 to 20,000 equivalents. In the case where the heat-sensitive adhesive layer (a) is in contact with a decorative layer formed by metal deposition or a functional layer with metal wiring or the like, it is preferable that the heat-sensitive adhesive layer (a) has a hydroxyl group as a crosslinkable functional group and is crosslinked with a polyfunctional isocyanate compound or the like in order to prevent corrosion or discoloration of the metal layer.

When a vinyl aromatic block copolymer composed of the aromatic vinyl monomer and the conjugated diene monomer is used as the copolymer contained in the adhesive composition, examples of the polymer block having a glass transition temperature of 90 ℃ or higher (S2) include polymer blocks composed of aromatic vinyl monomer units, for example, polymer blocks composed of styrene, α -methylstyrene, p-methylstyrene, m-methylstyrene, and the like. These can be used alone or in combination of 2 or more. Among them, styrene is preferably used for the polymer block (S2) because of its ease of adjustment to the above-mentioned predetermined viscoelastic range, suppression of bubble formation, suppression of peeling due to springback of the curved surface of the thermoplastic bonding material (B), suppression of bubble formation and peeling even when the above-mentioned bonded product is left in a high-temperature and high-humidity environment, and excellent moldability and thermosensitive adhesiveness of the thermosensitive adhesive layer (a).

The polymer block (S1) having a glass transition temperature of-20 ℃ or lower, which constitutes the vinyl aromatic block copolymer comprising the aromatic vinyl monomer and the conjugated diene monomer, includes polymer blocks comprising conjugated diene monomer units, and examples thereof include unsaturated hydrocarbons such as butadiene, isobutylene, and isoprene, and hydrogenated products thereof. From the viewpoint of easy adjustment to the above-mentioned predetermined viscoelastic range, easy relaxation of strain due to a difference in thermal expansion when the above-mentioned adhesive plaster is used in a cold environment or is repeatedly cooled and heated, and excellent heat-sensitive adhesiveness and deterioration resistance of the heat-sensitive adhesive layer (a), it is preferable to form the polymer block using a hydride of any one of unsaturated hydrocarbons selected from the group consisting of butadiene, isobutylene and isoprene (S1).

The weight average molecular weight of the block copolymer is not particularly limited, but is preferably within a range of 10,000 to 500,000, more preferably within a range of 50,000 to 200,000, and particularly preferably 70,000 to 120,000 for obtaining transparency and moldability of the heat-sensitive adhesive layer (a). By setting the above range, when the thermoplastic bonding material (B) is heated and bonded to the molded article (C), the thermosensitive adhesive layer (a) can obtain suitable flexibility and excellent thermosensitive adhesiveness, and can easily form microdomains of the polymer block (S1) and the polymer block (S2), suppress bubble formation due to gas that can be generated from the thermoplastic bonding material (B), peeling due to curved surface springback of the thermoplastic bonding material (B), or suppress bubble formation and peeling due to gas that can be generated from at least one of the thermoplastic bonding material (B) and the molded article (C) even if the adhesive is left in a high-temperature and high-humidity environment. Further, when the laminate is used in a cold environment or repeatedly cooled and heated, the strain due to the difference in thermal expansion between the thermoplastic bonding material (B) and the molded article (C) can be alleviated, and the floating and peeling between the thermoplastic bonding material (B) and the molded article (C) can be suppressed. The weight average molecular weight is a value measured by a Gel Permeation Chromatography (GPC) method under the following conditions.

A measuring device: high-speed GPC apparatus (HLC-8220 GPC, manufactured by Tosoh corporation)

Column: the following columns, manufactured by Tosoh corporation, were connected in series and used.

"TSKgel G5000" (7.8 mmI.D.. times.30 cm). times.1 roots

"TSKgel G4000" (7.8mm I.D.. times.30 cm). times.1 roots

"TSKgel G3000" (7.8 mmI.D.. times.30 cm). times.1 roots

"TSKgel G2000" (7.8 mmI.D.. times.30 cm). times.1 roots

A detector: RI (differential refractometer)

Column temperature: 40 deg.C

Eluent: tetrahydrofuran (THF)

Flow rate: 1.0 mL/min

Injection amount: 100 μ L (tetrahydrofuran solution with a sample concentration of 0.4% by mass)

Standard sample: the standard curve was made using the following standard polystyrene.

(Standard polystyrene)

TSKgel Standard polystyrene A-500 manufactured by Tosoh corporation "

TSKgel Standard polystyrene A-1000 manufactured by Tosoh corporation "

TSKgel Standard polystyrene A-2500 manufactured by Tosoh corporation "

TSKgel Standard polystyrene A-5000 manufactured by Tosoh corporation "

TSKgel Standard polystyrene F-1 manufactured by Tosoh corporation "

TSKgel Standard polystyrene F-2 manufactured by Tosoh corporation "

TSKgel Standard polystyrene F-4 manufactured by Tosoh corporation "

TSKgel Standard polystyrene F-10 manufactured by Tosoh corporation "

TSKgel Standard polystyrene F-20 manufactured by Tosoh corporation "

TSKgel Standard polystyrene F-40 manufactured by Tosoh corporation "

TSKgel Standard polystyrene F-80 manufactured by Tosoh corporation "

TSKgel Standard polystyrene F-128 manufactured by Tosoh corporation "

TSKgel Standard polystyrene F-288 manufactured by Tosoh corporation "

TSKgel Standard polystyrene F-550 manufactured by Tosoh corporation "

The weight average molecular weight is a value calculated as a converted value of standard polystyrene used for preparing a calibration curve by gel permeation chromatography (hereinafter, referred to as "GPC") analysis.

The content of the polymer block (S2) having a glass transition temperature of 90 ℃ or higher in the block copolymer is preferably 29 to 49 mass%, more preferably 33 to 46 mass%, and particularly preferably 36 to 42 mass%. When the polymer block (S2) is less than 29 mass%, the thermosensitive adhesive layer (a) is excessively softened when the thermoplastic bonding material (B) is heated and bonded to the molded product (C), and therefore, bubble formation due to gas that can be generated from the thermoplastic bonding material (B), peeling due to curved surface springback of the thermoplastic bonding material (B), and bubble formation and peeling due to gas that can be generated from at least one of the thermoplastic bonding material (B) and the molded product (C) when the bonded product is left in a high-temperature and high-humidity environment are likely to occur. When the polymer block (S2) is more than 49 mass%, the thermosensitive adhesive layer (a) has insufficient thermosensitive adhesiveness, and the adhesive composition cannot relax strain due to a difference in thermal expansion between the thermoplastic adhesive material (B) and the molded article (C) when used in a cold environment or repeatedly cooled and heated, and is likely to cause floating and peeling between the thermoplastic adhesive material (B) and the molded article (C).

The content of the polymer block (S1) having a glass transition temperature of-20 ℃ or lower in the block copolymer is preferably 51 to 71 mass%, more preferably 54 to 67 mass%, and particularly preferably 58 to 64 mass%. When the polymer block (S1) is less than 51 mass%, the softening of the thermosensitive adhesive layer (a) is insufficient when the thermoplastic bonding material (B) is heated and bonded to the molded article (C), the thermosensitive adhesive property of the thermosensitive adhesive layer (a) is insufficient, and the strain due to the difference in thermal expansion between the thermoplastic bonding material (B) and the molded article (C) cannot be alleviated when the bonded article is used in a cold environment or repeatedly cooled and heated, and the floating and peeling between the thermoplastic bonding material (B) and the molded article (C) are likely to occur. When the polymer block (S1) is more than 71 mass%, bubble formation by gas that can be generated from the thermoplastic bonding material (B) and peeling by springback of the curved surface of the thermoplastic bonding material (B) are likely to occur, and bubble formation and peeling by gas that can be generated from at least one of the thermoplastic bonding material (B) and the molded product (C) are likely to occur when the bonded product is left in a high-temperature and high-humidity environment.

The block copolymer contained in the adhesive composition may be 1 block copolymer or a mixture of 2 or more block copolymers having different polymer block contents. The content of the polymer block (S1) or (S2) when 2 or more block copolymers are contained means an average value of the content of the polymer block (S1) or (S2) in each block copolymer, and for example, the content of the polymer block (S1) or (S2) in a mixture of 2 block copolymers, i.e., the block copolymer (F) and the block copolymer (G), is calculated from the content of the polymer block (S1) or (S2) in each block copolymer of the block copolymers (F) and (G) by the following formula (1).

The content of the polymer block (S1) or (S2) in the block copolymer mixture [ mass% ] [ the content of the polymer block (S1) or (S2) in the block copolymer (F) ], x the content of the block copolymer (F) in the block copolymer mixture [ mass% ]/100] + [ the content of the polymer block (S1) or (S2) in the block copolymer (G) [ mass% ], x the content of the block copolymer (G) in the block copolymer mixture [ mass% ]/100] … formula (1)

When the number of the block copolymers contained in the adhesive composition is 2 or more, the absolute value of the difference in the content of the polymer blocks (S1) and (S2) between the block copolymers is preferably 50% by mass or less, more preferably 30% by mass or less, and particularly preferably 20% by mass or less, from the viewpoint of easy formation of domains and obtaining transparency of the heat-sensitive adhesive layer (a).

The domain size of the polymer block (S2) of the block copolymer contained in the adhesive composition formed on the surface or inside of the heat-sensitive adhesive layer (a) is preferably large in order to suppress bubble formation due to gas that can be generated from the thermoplastic bonding material (B), peeling due to springback of the curved surface of the thermoplastic bonding material (B), bubble formation and peeling due to gas that can be generated from at least one of the thermoplastic bonding material (B) and the molded article (C) even when the bonded article is left in a high-temperature and high-humidity environment, or floating and peeling due to strain caused by a difference in thermal expansion between the thermoplastic bonding material (B) and the molded article (C) when used in a cold environment or heated and cooled repeatedly, and the long side length of the domain of the polymer block (S2) is preferably equal to or longer than 160nm, more preferably, the film has a band-like structure such as a cylindrical shape or a layer shape having a length of a long side of 160nm or more on average. (e.g., fig. 1 and 2). The size of the domain is an average value obtained by measuring the length of the long side of the polymer block (S2) of any 5 or more domains in the domain of a phase separation obtained by scanning the surface or cross section of the heat-sensitive adhesive layer (a) in a 1 μm field of view using the phase mode of a Scanning Probe Microscope (SPM). The scanning probe microscope can be used for measurement in a proximity contact mode using "Nano-DST" manufactured by Pacific Nanotechnology. When the adhesive composition is formed of a mixture of 2 or more block copolymers, the domain size of the polymer block (S2) of the block copolymer contained in the adhesive composition means the domain size formed by the aggregation of the polymer blocks (S2) of the respective block copolymers forming the mixture. For example, when the adhesive composition contains a block copolymer X having a polymer block (S1X) and a polymer block (S2X) and a block copolymer Y having a polymer block (S1Y) and a polymer block (S2Y), the long side length of the 1 kind of domain is measured by forming domains of 1 kind of polymer block (S2) in which the polymer block (S2X) of the block copolymer X and the polymer block (S2Y) of the block copolymer X are aggregated on the surface or inside of the heat-sensitive adhesive layer (a).

The method for producing the block copolymer is not particularly limited, and examples thereof include living cationic polymerization disclosed in Japanese patent application laid-open Nos. H04-246488 and 2014-084334.

The block copolymer may be produced in the presence of an organic solvent.

Examples of the organic solvent include ester solvents such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate, ketone solvents such as acetone, methyl ethyl ketone, methyl butyl ketone, and cyclohexanone, ether ester solvents such as methyl cellosolve acetate and butyl cellosolve acetate, aromatic hydrocarbon solvents such as toluene and xylene, and amide solvents such as dimethylformamide and dimethylacetamide, which are used alone or in combination of 2 or more.

The adhesive composition may contain other additives as necessary.

As the other additives, for example, a silane coupling agent, an antioxidant, a light stabilizer, a rust inhibitor, a thixotropy imparting agent, a leveling agent, a tackifier, an antistatic agent, a flame retardant, a coloring dye, a coloring pigment, and the like can be used. These additives may be used alone, or 2 or more of them may be used in combination. Among these, when the bonded product produced by the method of the present invention is used in applications exposed outdoors or left in a high-temperature and high-humidity environment, high light resistance and yellowing resistance are required, and it is preferable to contain a light stabilizer, an antioxidant, and the like. In addition, in order to further improve the heat-sensitive adhesiveness, a thickener or the like is preferably contained.

The light stabilizer is a substance that traps radicals generated by photodegradation, and examples of the light stabilizer include radical traps such as thiol compounds, thioether compounds, and hindered amine compounds; ultraviolet absorbers such as benzophenone compounds and benzoate compounds. These light stabilizers may be used alone, or 2 or more of them may be used in combination. Among them, hindered amine compounds are preferably used from the viewpoint of further improving the yellowing resistance.

The amount of the light stabilizer used is preferably in the range of 0.01 to 10 parts by mass, and more preferably in the range of 0.05 to 3 parts by mass, based on 100 parts by mass of the total amount of the 1 or 2 or more block copolymers, from the viewpoint of further improving the light resistance and yellowing resistance.

As the antioxidant, a hindered phenol compound (primary antioxidant) which traps radicals generated by thermal degradation, a phosphorus compound which decomposes peroxides generated by thermal degradation, a sulfur compound (secondary antioxidant), and the like can be used.

Among these, in order to further improve the oxidation resistance, a phosphorus compound is preferably used, more preferably 1 or more antioxidants selected from the group consisting of triphenylphosphine, bis (2, 4-di-tert-butyl-6-methylphenyl) ═ ethyl ═ phosphite, and tris (2, 4-di-tert-butylphenyl) phosphite are used, and still more preferably triphenylphosphine and bis (2, 4-di-tert-butyl-6-methylphenyl) ═ ethyl ═ phosphite are used.

The amount of the antioxidant to be used is preferably in the range of 0.01 to 10 parts by mass, and more preferably in the range of 0.05 to 3 parts by mass, based on 100 parts by mass of the total amount of the 1 or 2 or more block copolymers, from the viewpoint of further improving the oxidation resistance.

As the tackifier, any tackifier resin such as a styrene resin, a rosin resin, a terpene resin, or an aliphatic hydrocarbon resin can be used, and a rosin resin or a terpene resin which can be easily adjusted to the above-mentioned predetermined viscoelastic range is preferably used, and from the viewpoint of excellent light resistance and yellowing resistance, a hydrogenated rosin resin or a terpene resin is more preferably used, and particularly a hydrogenated rosin ester resin or a terpene phenol resin is preferably used.

The amount of the thickener used is preferably in the range of 1 to 30 parts by mass, and more preferably in the range of 5 to 20 parts by mass, from the viewpoint of further improving the heat-sensitive adhesiveness, relative to 100 parts by mass of the total amount of the 1 or 2 or more block copolymers, in order not to impair the suppression of bubble formation during heating.

In addition, in order to suppress shrinkage when the heat-sensitive adhesive layer (a) is applied to a release liner, and to improve handling properties such as a dicing step of the heat-sensitive adhesive sheet (a) and a peeling step of the release liner, an arbitrary thermoplastic resin may be used together with the above components within a range not to hinder transparency. The thermoplastic resin may be a urethane resin, an acrylic resin, a polyester resin, an epoxy resin, or the like, and more preferably a thermoplastic resin containing a crosslinkable functional group such as a hydroxyl group, a carboxyl group, or a glycidyl group in a resin in combination and capable of being crosslinked by a crosslinking agent.

The thermoplastic resin is preferably in a semi-solid or solid state at 25 ℃ in an atmosphere, and the weight average molecular weight is preferably in the range of 5,000 to 200,000, more preferably in the range of 15,000 to 100,000. The weight average molecular weight of the thermoplastic resin is a value measured in the same manner as the weight average molecular weight of the block copolymer.

The amount of the thermoplastic resin used is preferably 1 to 50 parts by mass based on 100 parts by mass of the total amount of the 1 or 2 or more block copolymers, and particularly preferably 3 to 20 parts by mass in order to prevent the cohesive force of the block copolymer contained in the heat-sensitive adhesive layer (a) from decreasing and to suppress bubble formation, floating, and peeling when heated.

In applications where an electric signal is read by passing a high-frequency electric pulse near the adherend bonded by the method of the present invention, a polyolefin resin, an inorganic filler, or the like may be added to the thermosensitive adhesive layer (a) in order to adjust the dielectric loss tangent and the relative permittivity of the thermosensitive adhesive layer (a) within a range that does not impair transparency.

The polyolefin resin is preferably an olefin resin such as a polyethylene resin or a polypropylene resin having a relative dielectric constant of about 2 to 3, or a rubber resin such as an isoprene resin or a butadiene resin, and in order to improve compatibility with the composition, the side chain may be partially chlorinated or carboxylic acid-modified to partially increase polarity.

As the inorganic filler, boron nitride, forsterite, cordierite, silica, magnesia, alumina or the like having a dielectric loss tangent of 10 is preferably used^-4～10^-5The inorganic filler is preferably used to the extent that the block copolymer or the like has excellent compatibility with the adhesive composition and improves the transparency of the heat-sensitive adhesive layer (a).

The inorganic filler may be an inorganic filler having any shape such as a spherical shape or a crushed shape, and in order to improve compatibility with the adhesive composition, an inorganic filler having a surface treated by titanate coupling, aluminate coupling, silane coupling, or the like may be used.

The particle size of the inorganic filler is preferably 10nm or more and less than 50 μm in a cumulative distribution 50% of the undersize, more preferably 10nm to 20 μm, and particularly preferably 1 μm to 10 μm in order to improve the transparency of the adhesive layer (a) and to achieve both good dispersibility and coating easiness of the inorganic filler. The undersize cumulative distribution 50% particle size of the inorganic filler may be measured by using a laser diffraction particle size distribution analyzer SALD-3100 manufactured by Shimadzu corporation and isopropyl alcohol as a dispersion medium.

The amount of the polyolefin resin and the inorganic filler to be used is preferably 1 to 50 parts by mass in total based on 100 parts by mass of the total amount of the 1 or 2 or more block copolymers, and more preferably 5 to 20 parts by mass in order to reduce the dielectric loss tangent and the relative permittivity of the adhesive sheet and to suppress the decrease in adhesiveness of the heat-sensitive adhesive layer (a).

[ Heat-sensitive adhesive sheet (A) ]

The heat-sensitive adhesive sheet (a) used in the method of the present invention can be produced by, for example, applying a solution of an adhesive composition obtained by dissolving the adhesive composition in an organic solvent or the like to the surface of a release liner and optionally drying the solution to form a heat-sensitive adhesive layer (a).

Examples of a method for applying the solution of the adhesive composition to the surface of the release liner include a method of applying the solution by a die coater or a die coater. The drying may be performed by using a dryer set at a temperature of about 80 to 120 ℃.

Examples of the release liner include paper such as kraft paper, cellophane paper and fine paper, resin films such as polyethylene, biaxially stretched polypropylene, extruded polypropylene and polyethylene terephthalate, laminated paper obtained by laminating the paper and the resin films, and a liner obtained by subjecting the paper to a filling treatment with clay, polyvinyl alcohol or the like and then to a release treatment with a silicone compound or the like on one or both surfaces thereof. In order to improve the transparency of the heat-sensitive adhesive sheet (a), a release liner obtained by applying a release treatment to a resin film is preferably used.

Examples of the release agent for the release liner include silicone release agents, aminoalkyd release agents, silicone-modified aminoalkyd release agents, long-chain alkyl release agents, fluorine release agents, and the like.

The thickness of the release liner is preferably 38 to 150. mu.m, more preferably 50 to 100. mu.m. By setting the thickness as described above, the smoothness of the surface of the heat-sensitive adhesive layer (a) after drying can be improved, and the release liner is less likely to be stretched in the drying step, and the winding mark after winding into a roll shape can be prevented.

In addition, when the adhesive is produced through a step of heating a heat-sensitive adhesive sheet (a) to 90 to 200 ℃ in a state where a release liner is laminated on one surface, pressing and adhering the surface side of the heat-sensitive adhesive layer (a) of the heat-sensitive adhesive sheet (a) to the molded article (C), peeling off the release liner, and then heating only a thermoplastic adhesive material (B) to 90 to 200 ℃ and pressing and adhering the thermoplastic adhesive material (B) to the heat-sensitive adhesive layer (a), the release liner using a thermoplastic resin which has a low softening temperature and is easily heat-stretched, such as polyethylene, biaxially stretched polypropylene, or extruded polypropylene, as a base material is more preferable as the release liner.

The heat-sensitive adhesive sheet (a) may be sandwiched by another arbitrary release liner before being used in the bonding step. In order to suppress poor peeling of the adhesive sheet when the release liner is peeled off again after being sandwiched, it is preferable to use release liners having different peeling forces on both sides. Since the heat-sensitive adhesive layer (a) lacks pressure-sensitive adhesiveness at room temperature, the heat-sensitive adhesive sheet (a) is likely to float when wound into a roll, and it is preferable to use a release liner coated on at least one side with a silicone-based release agent that has been re-peeled with a release control agent or the like, or a non-silicone-based release agent such as an aminoalkyd-based release agent, a silicone-modified aminoalkyd-based resin, or a long-chain alkyl-based resin.

The thickness of the heat-sensitive adhesive layer (a) is preferably 10 to 300. mu.m, more preferably 25 to 250 μm, and particularly preferably 50 to 200. mu.m. In the case of forming the thickness, the thermosensitive adhesive layer (a) may be laminated in 2 or more layers, in addition to the single layer of thermosensitive adhesive layer (a). When 2 or more layers of the thermosensitive adhesive layer (a) are laminated, 2 or more layers of the thermosensitive adhesive layer (a) having different compositions may be laminated as long as the viscoelasticity within the predetermined range is satisfied.

When the thermosensitive adhesive layer (a) is laminated with 2 or more layers, the following method is preferably used because of lack of adhesiveness at room temperature: a method of heating and pressure-bonding the adhesive surfaces of the thermosensitive adhesive layer (a) laminated on the release liner through a gap between a rotating rubber roller and a rotating metal roller heated to 90 ℃ or higher; and a method in which the adhesive surfaces of the thermosensitive adhesive layer (a) laminated on the release liner are temporarily bonded to each other at room temperature so as not to allow air bubbles to enter, and the thermosensitive adhesive layer (a) is laminated with 2 or more layers by heat curing or the like at 50 ℃ or higher for 24 hours or longer.

The heat-sensitive adhesive sheet (a) may have a structure in which the heat-sensitive adhesive layer (a) is laminated on both surfaces of a base material. By embedding the base material in the heat-sensitive adhesive layer (a), the handling property of the heat-sensitive adhesive sheet (a) is improved, and extrusion, chipping, and the like of the heat-sensitive adhesive layer (a) at the time of cutting are reduced, and excellent dimensional stability is obtained, which is preferable.

As the substrate, any film or web material such as polyethylene terephthalate, polybutylene terephthalate, polyimide, polyphenylene sulfide, polyphenylene ether, polypropylene, polyethylene, polystyrene, etc. can be used, and polyethylene terephthalate, polypropylene, polyethylene, polystyrene, etc. having excellent transparency and heat extensibility are particularly preferably used. The substrate is preferably a substrate having a thickness of about 1/2 or less, more preferably 1 to 50 μm, and still more preferably 2 to 25 μm, based on the total thickness of the heat-sensitive adhesive sheet (A).

When the thermosensitive adhesive layer (a) is laminated on the base material, it is preferable to laminate the thermosensitive adhesive layer (a) on the surface of the base material by coating the composition of the thermosensitive adhesive layer (a) on the surface of the base material, or by a method of thermally pressing the thermosensitive adhesive layer (a) laminated on the release liner while passing through a gap between a rotating rubber roller and a metal roller heated to 90 ℃ or higher because of lack of adhesiveness at room temperature.

The heat-sensitive adhesive sheet (A) is preferably an adhesive sheet having a thickness of 10 to 300. mu.m, more preferably an adhesive sheet having a thickness of 25 to 250 μm, and particularly preferably an adhesive sheet having a thickness of 50 to 200. mu.m. The heat-sensitive adhesive sheet (a) having a thickness in the above range has excellent heat-sensitive adhesiveness, can suppress bubble formation due to gas that can be generated from the thermoplastic bonding material (B) at the time of heat bonding and peeling due to the curved surface repulsive force of the thermoplastic bonding material (B), and can suppress bubble formation and peeling due to gas that can be generated from at least one of the thermoplastic bonding material (B) and the molded product (C) without going through a curing step even in a high-temperature and high-humidity environment. The thickness is a thickness without a release liner.

The heat-sensitive adhesive sheet (a) having the heat-sensitive adhesive layer (a) has excellent heat-sensitive adhesiveness, and when the heat-sensitive adhesive sheet (a) is used as an adhesive layer and a thermoplastic adhesive material (B) is heated to 90 to 200 ℃ and adhered to the surface of a molded article (C), bubble formation due to gas that can be generated from the thermoplastic adhesive material (B) and peeling due to curved surface springback of the thermoplastic adhesive material (B) can be suppressed by the heat-sensitive adhesive layer (a) constituting the heat-sensitive adhesive sheet (a), and a sticker can be obtained without impairing the appearance. Furthermore, even when the bonded product bonded with the heat-sensitive adhesive sheet (a) composed of the heat-sensitive adhesive layer (a) is placed in a high-temperature and high-humidity environment, a cold environment, or a hot and cold environment, bubble formation due to gas that can be generated from at least one of the thermoplastic bonding material (B) and the molded product (C), and peeling due to strain caused by a difference in thermal expansion can be suppressed.

The heat-sensitive adhesive sheet (a) is preferably transparent, and when the release liner is removed from both surfaces, it is preferable to use an adhesive sheet having a light transmittance of from 380nm to 780nm of 80% or more and a haze of 5.0 or less, more preferably an adhesive sheet having a light transmittance of from 380nm to 780nm of 85% or more and a haze of 2.0 or less, and particularly preferably an adhesive sheet having a light transmittance of from 380nm to 780nm of 90% or more and a haze of 1.0 or less. By setting the range, the design can be improved without impairing the appearance of the patch. The heat-sensitive adhesive sheet (a) preferably maintains the above light transmittance and haze even after being left in a high-temperature and high-humidity environment.

The heat-sensitive adhesive sheet (A) has heat-sensitive adhesiveness, and the 180 DEG peel adhesion immediately after attachment in an environment of 23 ℃ and 50% RH of relative humidity is preferably 1N/cm or less, more preferably 0.7N/cm or less, and particularly preferably 0.1N/cm to 0.5N/cm. When the thermoplastic bonding material (B) on which the heat-sensitive adhesive sheet (a) is laminated or the heat-sensitive adhesive sheet (a) on which the release liner is laminated is set to the above range, the position correction is easy when the bonding apparatus such as a compressed air molding machine, a vacuum molding machine, a TOM molding machine, or the like is mounted, and dirt or dust does not adhere to the surface of the adhesive layer and the appearance after bonding is not impaired. Further, when the thermoplastic bonding material is first molded in accordance with the shape of the molded product and then bonded to the surface of the molded product with the liquid adhesive or the adhesive sheet, the thermoplastic bonding material is easily peeled off even when the bonding position is shifted, so that the position correction from the shifted position is easily performed, and bubbles are not easily taken in at the interface between the thermosensitive adhesive layer (a) and the molded product (C).

The 180 DEG peel adhesion after the heat-sensitive adhesive sheet (A) is preferably 5N/cm or more, more preferably 8N/cm to 50N/cm, and particularly preferably 10N/cm to 30N/cm in an environment of 23 ℃ and 50% RH at relative humidity and an environment of 90 ℃ respectively. By setting the above range, when the heat-sensitive adhesive sheet (a) is used as an adhesive layer and the thermoplastic bonding material (B) is heated to 90 to 200 ℃ and bonded to the surface of the molded product (C), bubble formation due to gas that can be generated from the thermoplastic bonding material (B) and peeling due to curved surface springback of the thermoplastic bonding material (B) can be suppressed by the heat-sensitive adhesive layer (a) constituting the heat-sensitive adhesive sheet (a). Furthermore, even when the bonded product bonded with the thermosensitive adhesive sheet (a) composed of the thermosensitive adhesive layer (a) is left in a high-temperature and high-humidity environment, peeling caused by bubble formation due to gas that can be generated from at least one of the thermoplastic bonding material (B) and the molded product (C) can be suppressed.

The 180 DEG peel adhesion after the heat-sensitive adhesive sheet (A) is preferably 1N/cm or more, more preferably 2N/cm to 30N/cm, and particularly preferably 3N/cm to 20N/cm in an environment of-20 ℃. By setting the range, even when the bonded object is left in a cold environment or a cold and hot environment, the floating and peeling between the thermoplastic bonding material (B) and the molded object (C) due to strain caused by a difference in thermal expansion between the thermoplastic bonding material (B) and the molded object (C) can be suppressed.

Note that the 180 ° peel adhesion immediately after attachment in an environment of 23 ℃ temperature and 50% RH relative humidity was obtained as follows: the release liner on one side of the heat-sensitive adhesive sheet (a) having the release liner laminated on both sides thereof was removed, a polycarbonate sheet having a thickness of 125 μm (Panlite PC-2151 manufactured by teiman corporation) was bonded to a hot laminator heated to 120 ℃, and then cut into a width of 1cm, the polycarbonate sheet was placed on a polycarbonate sheet having a smooth surface and a thickness of about 1mm to 3mm under an atmosphere of 23 ℃ and 50% RH, and a sample was prepared by applying 1 reciprocal pressing at a speed of 300 mm/min using a 2kg roller, and the peel resistance when the polycarbonate sheet was stretched at a speed of 50 mm/min in a 180 ° direction within 1 minute after the pressing was measured by a tensillon type tensile tester (manufactured by a & D and RTG-1210) equipped with a thermostatic bath under an atmosphere of 23 ℃ and 50% RH.

The 180 ° peel adhesion after heat application was obtained as follows: instead of the above-mentioned 1-pass pressure by the 2kg roll, a sample was prepared by heating at 140 ℃ for 15 seconds and pressurizing at 0.2MPa by a hot press apparatus (manufactured by Tester industries, Ltd. "TP-750 Air press"), and the peel resistance when the polycarbonate sheet was stretched at a speed of 50 mm/min in the 180 ℃ direction was measured in the same manner as described above under an atmosphere of-20 ℃, an atmosphere of 23 ℃ and a relative humidity of 50% RH and an atmosphere of 90 ℃.

Note that the humidity was not controlled when the temperature was measured at-20 ℃ and 90 ℃.

2. Method for manufacturing article

The method for producing an article of the present invention is a method for producing an article in which the thermoplastic adhesive material (B) is adhered to the surface of the molded article (C) using the thermosensitive adhesive layer (a) of the thermosensitive adhesive sheet as an adhesive layer.

[ thermoplastic adhesive Material (B) ]

Examples of the thermoplastic bonding material (B) to be bonded by the method of the present invention include a transparent member made of plastic.

Examples of the thermoplastic adhesive material (B) include any resin base material, and for example, a resin base material such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, cellophane, diacetyl cellulose, triacetyl cellulose, acetyl cellulose butyrate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl acetate copolymer, polystyrene, polycarbonate, polymethylpentene, polysulfone, polyether ether ketone, polyether sulfone, polyether imide, polyimide, nylon, (meth) acrylic resin, or an alloy thereof can be used. Among these, polycarbonate, a (meth) acrylic resin, and an alloy thereof are preferable as the resin base material in view of achieving both high transparency and surface hardness. However, a resin substrate such as polycarbonate, a (meth) acrylic resin, and an alloy thereof is likely to generate gas instantaneously when heated at about 85 ℃ or higher, which causes formation of bubbles. In the bonding method of the present invention using the heat-sensitive adhesive sheet (a), bubbles due to the generation of the gas are less likely to be formed even when the resin base material is used, and a bonded product having excellent transparency and surface hardness can be obtained without impairing the appearance.

The thermoplastic bonding material (B) is preferably 0.05mm to 5mm thick, more preferably 0.1mm to 1mm thick, and particularly preferably 0.125mm to 0.4mm thick. By providing the above thickness, durability in protecting the surface of the molded article (C) can be provided.

In addition, for the purpose of preventing surface scratches, improving smoothness, and the like, the thermoplastic bonding material (B) may be formed by laminating an arbitrary hard coat layer, matte layer, and the like on the surface of the thermoplastic bonding material (B) by coating, transfer, coextrusion, and the like.

In the case where the thermoplastic bonding material (B) is used for an article used outdoors such as an exterior trim of an automobile, a layer absorbing ultraviolet rays having a wavelength of 325nm to 380nm may be provided on the surface or inside of the thermoplastic bonding material (B) in order to improve the outdoor light resistance of the thermoplastic bonding material (B), the heat-sensitive adhesive sheet (a) and the molded article (C) located on the back layer. Examples of the method for forming the ultraviolet absorbing layer include a method of applying a coating agent containing an arbitrary ultraviolet absorber or the like to the surface of the thermoplastic bonding material (B), a method of mixing an arbitrary ultraviolet absorber into the thermoplastic bonding material (B), and the like. In order to simplify the process, the coating may be added to the hard coat layer, matte layer, or the like. In the case of the thermoplastic laminating material (B) containing the ultraviolet absorbing layer, the ultraviolet transmittance at a wavelength of 325nm to 380nm is preferably 0% to 20%, and more preferably 0% to 10% from the viewpoint of imparting outdoor light resistance.

The thermoplastic adhesive material (B) preferably has a light transmittance of 80 to 100% at a wavelength of 380 to 780nm in the visible light region and a haze of 0 to 5.0%, and more preferably has a light transmittance of 85 to 100% at a wavelength of 380 to 780nm and a haze of 0 to 2.0% or less. By setting the range, the design of the patch can be improved.

The thermoplastic adhesive sheet (B) may be a heat-sensitive adhesive sheet in which a decorative layer and a functional layer are laminated in advance on the surface side on which the heat-sensitive adhesive sheet (a) is laminated, and the decorative layer and the functional layer are laminated between the heat-sensitive adhesive layer (a) and the thermoplastic adhesive sheet (B). The thickness of the decorative layer and the functional layer is preferably 35% or less, more preferably 25% or less, and particularly preferably 10% or less of the thickness of the heat-sensitive adhesive sheet. By setting the above range, in the step of bonding the thermoplastic bonding material (B) by heating, the decorative layer and the functional layer are embedded in the thermosensitive adhesive layer (a) of the thermosensitive adhesive sheet (a) without height difference at the time of heating bonding, and the design of the adhesive can be improved.

The method of laminating the decorative layer and the functional layer may be any method, and examples thereof include: a method of directly applying a coloring paint, a metal-containing paint, or the like to the surface of the thermoplastic bonding material (B) by a screen printer, a gravure printer, or the like; a method of transferring a transfer foil, in which a decorative layer and a functional layer are previously laminated, to the surface of the thermoplastic bonding material (B); a method of applying a paint containing a colored paint, a metal-containing paint, or the like to the surface of the thermoplastic bonding material (B) by spraying; a method of performing sputtering, plating, or etching after the metal foil is bonded to the surface of the thermoplastic bonding material (B).

A plurality of the thermoplastic bonding materials (B) may be bonded. When a plurality of the thermoplastic bonding materials (B) are bonded, the same kind may be bonded, and other kinds of the above-mentioned examples may be bonded.

[ Molding (C) ]

Specific examples of the molded article (C) to be bonded by the method of the present invention include molded articles having a decorative layer for the purpose of imparting design properties, light-shielding properties, and the like.

The molded article (C) may be formed by any molding method, and may be, for example, a molded article formed by injection molding, press molding, or the like and decorated by printing, painting, plating, or the like. The molded article (C) may have any shape and thickness.

As the material of the molded article (C), inorganic materials such as glass and ceramics; metals such as stainless steel and aluminum; resins such as polycarbonate, polymethyl methacrylate, an alloy of polycarbonate and acrylonitrile-butadiene-styrene copolymer, polyethylene terephthalate, polybutylene terephthalate, polyimide, polyphenylene sulfide, polyphenylene oxide, polypropylene, polyethylene, and polystyrene; for the laminate, etc., molded resin articles such as polycarbonate, acrylic resin, and an alloy of polycarbonate and acrylonitrile-butadiene-styrene copolymer are preferably used because of ease of molding.

The molded article (C) may be a heat-sensitive adhesive sheet in which a decorative layer and a functional layer are laminated in advance on the surface side on which the heat-sensitive adhesive sheet (a) is laminated, and the decorative layer and the functional layer are laminated between the heat-sensitive adhesive layer (a) and the molded article (C). The thickness of each layer such as the decorative layer and the functional layer laminated on the surface side on which the thermosensitive adhesive sheet (a) is laminated is preferably 35% or less, more preferably 25% or less, and particularly preferably 10% or less of the thickness of the thermosensitive adhesive sheet. By setting the above range, in the step of bonding the heat-sensitive adhesive sheet (a) to the molded article (C), the decorative layer and the functional layer are embedded in the heat-sensitive adhesive layer (a) of the heat-sensitive adhesive sheet (a) without a step, and the design of the bonded article can be improved.

The method of laminating the decorative layer and the functional layer may be any method, and examples thereof include: a method of directly applying a colored coating material or a metal-containing coating material to the surface of the molded article (C) by a screen printer, a gravure printer, or the like; a method of transferring the molded article (C) to the surface thereof by using a transfer foil on which a decorative layer and a functional layer are previously laminated; a method of applying a paint containing a colored paint, a metal-containing paint, or the like to the surface of the molded article (C) by spray coating; a method of performing sputtering a or plating on the surface of the molded article (C), or a method of bonding a metal foil and then etching the metal foil.

A plurality of the molded articles (C) may be bonded to each other. When a plurality of molded articles (C) are laminated, the same kind may be laminated, and other kinds of the above-mentioned examples may be laminated.

[ bonding method ]

The method for producing an article of the present invention, which is a method for producing an article to which the thermoplastic adhesive material (B) is adhered to the molded article (C) by the heat-sensitive adhesive sheet (a), comprises a method for adhering the thermoplastic adhesive material (B) to the surface of the molded article (C) by heating the thermoplastic adhesive material (B) to 90 to 200 ℃ using the heat-sensitive adhesive sheet (a) having the heat-sensitive adhesive layer (a) as an adhesive layer, wherein the heat-sensitive adhesive layer (a) has a peak temperature of a tensile loss tangent (tan δ) measured in a range of-50 to 200 ℃ and at a frequency of 3Hz of at least one or more than 90 ℃ and at least one or more than-20 ℃, and a tensile storage modulus (E') at 100 ℃._a100) Is 5 x 10⁵Pa～1×10⁸Pa。

The bonding method in the method for producing the above-mentioned article is not particularly limited, but is preferably a first embodiment in which the following step [1] and step [2] are sequentially performed, a second embodiment in which the following step [3] and step [4] are sequentially performed, or a third embodiment in which the following step [1], step [5] and step [6] are sequentially performed.

That is, the first aspect of the method for manufacturing an article is a method for manufacturing an article including the following steps in this order: a step [1] of laminating the heat-sensitive adhesive layer (a) of the heat-sensitive adhesive sheet (A) and the thermoplastic laminating material (B) to form a laminate; and a step [2] of, after the step [1], heating the thermoplastic adhesive material (B) or the thermosensitive adhesive layer (a) to 90 to 200 ℃ to bond the thermosensitive adhesive layer (a) of the laminate and the molded article (C) under pressure. The thermoplastic bonding material (B) and the molded article (C) may be bonded simultaneously in 2 or more kinds in each step. The bonding process between the thermoplastic bonding material (B) and the molded article (C) by the molding machine described later is generally a mass production method, and may be one of rate-limiting steps in the production process of the article.

In the first aspect, the heat-sensitive adhesive sheet (a) may have a release liner made of a thermoplastic resin material as a base material on one or both surfaces thereof. In this case, in the step [1], when the release liner a is disposed on the surface of the thermosensitive adhesive layer (a) to be bonded to the thermoplastic bonding material (B), the step [1] is performed after the release liner a is peeled. In the step [2], when the release liner B is disposed on the surface of the thermosensitive adhesive layer (a) that is in contact with the molded article, the step [2] is performed after the release liner B is peeled off.

In the step [1], since the heat-sensitive adhesive sheet (a) lacks adhesiveness at room temperature, it is preferable to temporarily bond the heat-sensitive adhesive layer (a) and the thermoplastic adhesive material (B). Specific examples of the temporary bonding method include: a method in which the heat-sensitive adhesive layer (a) of the heat-sensitive adhesive sheet (a) and the thermoplastic adhesive material (B) are heated and closely adhered through a gap between a rotating rubber roller and a rotating metal roller heated to 90 ℃ or higher in a state in which a release liner is laminated on the surface of the heat-sensitive adhesive sheet (a) opposite to the thermoplastic adhesive material (B); and a method in which the heat-sensitive adhesive layer (a) of the heat-sensitive adhesive sheet (a) and the thermoplastic adhesive material (B) are temporarily bonded to each other at room temperature so as not to allow air bubbles to enter, and are heat-cured at 50 ℃ or higher for 24 hours or longer. In this case, the thermosensitive adhesive layer (a) and the thermoplastic adhesive material (B) are permanently bonded to each other after the step [2 ]. In the step [2], it is preferable that the molded product (C) is pressed against the surface of the heat-sensitive adhesive layer (a) with a molding machine at a pressure of about 0.1MPa or more, or the surface side of the thermoplastic bonding material (B) is pressurized with compressed air at about 0.1MPa or more, so that the thermoplastic bonding material (B) and the heat-sensitive adhesive sheet (a) are bonded to the surface of the molded product (C) while being deformed in the three-dimensional direction.

In addition, a second aspect of the method for manufacturing an article is a method for manufacturing an article including the following steps in this order: a step [3] of heating the thermosensitive adhesive layer (a) of the thermosensitive adhesive sheet (A) to 90 to 200 ℃ and pressing and adhering the thermosensitive adhesive layer (a) of the thermosensitive adhesive sheet (A) to the molded article (C); and a step [4] of heating the thermoplastic bonding material (B) to 90 to 200 ℃ after the step [3], and bonding the thermoplastic bonding material (B) and the thermosensitive adhesive layer (a) by pressing. The thermoplastic bonding material (B) and the molded article (C) may be bonded simultaneously in 2 or more kinds in each step. According to the method for producing an article of the second aspect, since only the thermoplastic bonding material (B) that can generate gas by heating is heated, and the heat-sensitive adhesive sheet (a) is bonded after the gas is released from the thermoplastic bonding material (B), the expansion with the heat-sensitive adhesive layer (a) due to the gas generated by the thermoplastic bonding material (B) can be reduced.

The second aspect of the method for manufacturing an article described above is preferably a method for manufacturing an article including the following steps in this order: a step [3] of using a heat-sensitive adhesive sheet (A) on which a release liner made of a thermoplastic resin material is laminated, heating the heat-sensitive adhesive layer (a) of the heat-sensitive adhesive sheet (A) to 90 to 200 ℃ together with the release liner, and pressing and bonding the molded article (C) to the surface of the heat-sensitive adhesive layer (a) of the heat-sensitive adhesive sheet (A) opposite to the surface on which the release liner is laminated; and a step [4] of heating the thermoplastic bonding material (B) to 90 to 200 ℃ after the step [3], and pressing and bonding the thermoplastic bonding material (B) to the heat-sensitive adhesive layer (a) from which the release liner has been removed. This is because, by using the heat-sensitive adhesive sheet (a) in which the release liner made of a thermoplastic resin material is laminated, the heat-sensitive adhesive layer (a) is heated together with the release liner in the step [3] and is bonded to the molded article (C) in a state in which the release liner is laminated, so that the tensile strength of the heat-sensitive adhesive sheet (a) can be improved, the heat-sensitive adhesive sheet (a) is easily pressed against the molded article (C), and uneven adhesion at the interface between the heat-sensitive adhesive layer (a) and the molded article (C) and air bubbles mixed in the interface can be prevented.

In the step [3], it is preferable that the heat-sensitive adhesive sheet (a) having a release liner comprising a thermoplastic resin material as a base material laminated on one surface thereof is heated, and then the molded product (C) is pressed against the surface of the heat-sensitive adhesive layer (a) by a molding machine, or the heat-sensitive adhesive sheet (a) is pressed on the surface side of the thermoplastic release liner to adhere to the surface of the molded product (C) while deforming the heat-sensitive adhesive sheet (a) in the three-dimensional direction together with the release liner. This is because the adhesive property to the surface of the molded article (C) after deformation can be improved and firm adhesion can be performed.

The pressure at which the molded article (C) is pressed against the surface of the heat-sensitive adhesive layer (a) in the heated heat-sensitive adhesive sheet (a) is preferably about 0.1MPa or more. Alternatively, when the surface side of the thermoplastic release liner of the heat-sensitive adhesive sheet (a) is pressurized, the pressure is preferably applied by compressed air of about 0.1MPa or more.

In the step [4], it is preferable that the heat-sensitive adhesive layer (a) is pressed against the thermoplastic adhesive layer (B) at a pressure of about 0.1MPa or more, or the surface side of the thermoplastic adhesive layer (B) is pressurized with compressed air of about 0.1MPa or more, and the thermoplastic adhesive layer (B) is attached to the surface of the heat-sensitive adhesive layer (a) while being three-dimensionally deformed.

In addition, a third aspect of the method for manufacturing an article is a method for manufacturing an article, which includes the following steps in this order: a step [1] of forming a laminate by bonding the heat-sensitive adhesive layer (a) of the heat-sensitive adhesive sheet (A) to the thermoplastic bonding material (B) in the same manner as in the first embodiment; a step [5] of, after the step [1], heating the thermoplastic adhesive material (B) or the thermosensitive adhesive layer (a) of the laminate to 90 to 200 ℃ and pressing the same with a mold box of the same type as the molded article (C) to mold the laminate into the shape of the molded article (C); and a step [6] of, after the step [5], covering the molded article (C) with the molded laminate, and heating the heat-sensitive adhesive layer (a) to 90 to 200 ℃ from at least one side of the thermoplastic adhesive material (B) or the molded article (C) to bond the heat-sensitive adhesive layer (a) and the molded article (C). The thermoplastic bonding material (B) and the molded article (C) may be bonded simultaneously in 2 or more kinds in each step.

In the method for producing an article according to the third aspect, the thermoplastic bonding material (B) on which the heat-sensitive adhesive sheet (a) is laminated is molded in advance to stabilize the shape, so that strain caused by deformation of the thermoplastic bonding material (B) when the thermoplastic bonding material (B) is bonded to the surface of the molded article (C) by heating can be reduced, and floating and peeling after bonding can be reduced. Further, since the heat-sensitive adhesive sheet of the present invention has low room-temperature adhesiveness, the thermoplastic bonding material (B) molded in advance into the shape of the molded article (C) can be easily fitted to the molded article (C) via the heat-sensitive adhesive sheet, and the molded thermoplastic bonding material (B) can be bonded to the molded article (C) in close contact therewith.

Examples of the molding machine used in the method of manufacturing an article include any molding machines such as a compressed air molding machine, a vacuum molding machine, a TOM molding machine, an NGF molding machine, and a hot press molding machine. As an example of the sticking process of the first aspect using the molding machine, an article can be manufactured, for example, through the following processes: a step of mounting the thermoplastic bonding material (B) and the molded product (C) on a molding machine, the thermoplastic bonding material (B) and the molded product (C) having the thermosensitive adhesive sheet (A) laminated thereon having passed through the step [1 ]; a step of depressurizing the inside of the tank in which the molded article (C) is disposed; heating the thermoplastic bonding material (B) on which the heat-sensitive adhesive sheet (A) has been laminated through the step [1] at 90 to 200 ℃; a step of pressing the thermoplastic bonding material (B) on which the heat-sensitive adhesive sheet (a) is laminated, with compressed air or a pressing plate while raising the molded article (C) to press the molded article (C) to the heat-sensitive adhesive layer (a) after heating; and a step of removing the adhesive from the molding machine and trimming the thermoplastic adhesive material (B) laminated with the heat-sensitive adhesive sheet (a) extruded from the molding.

As an example of the sticking process of the second aspect using the molding machine, for example, an article can be manufactured through the following steps: a step of mounting the heat-sensitive adhesive sheet (A) having the release liner laminated on one surface thereof and the molded article (C) on a molding machine; a step of depressurizing the inside of the tank in which the molded article (C) is disposed; heating a heat-sensitive adhesive sheet (A) having a release liner laminated on one surface thereof at 90 to 200 ℃; a step of raising the molded product (C) after heating and pressing the molded product (C) against the heat-sensitive adhesive layer (a), and pressing the heat-sensitive adhesive sheet (a) having the release liner laminated on one surface thereof with compressed air, a pressing plate, or the like; removing the adhesive from the molding machine and trimming the heat-sensitive adhesive sheet (a) extruded from the molding and having a release liner laminated on one surface thereof; removing the release liner from the molded product (C) laminated with the heat-sensitive adhesive sheet (A), and mounting the release liner on a molding machine together with the thermoplastic adhesive sheet (B); a step of depressurizing the inside of the tank provided with the molded article (C) in which the heat-sensitive adhesive sheet (a) is laminated, in the same manner as described above; heating the thermoplastic bonding material (B) at 90 to 200 ℃ to raise the molding (C) and press the thermosensitive adhesive layer (a) to the thermoplastic bonding material (B), and pressing the thermoplastic bonding material (B) with compressed air, a pressing plate, or the like; and a step of removing the laminate from the molding machine and trimming the thermoplastic bonding material (B) extruded from the molded product.

As an example of the sticking process of the third embodiment using the molding machine, an article can be manufactured, for example, through the following processes: a step of mounting the thermoplastic bonding material (B) having the heat-sensitive adhesive sheet (A) laminated thereon through the step [1] and the molded product (C) on a molding machine; a step of depressurizing the inside of a groove provided with a mold box having mold releasability on the surface and having the same shape as the molded article (C); heating the thermoplastic bonding material (B) on which the heat-sensitive adhesive sheet (A) has been laminated through the step [1] at 90 to 200 ℃; a step of raising the mold box after heating and pressing the mold box to the heat-sensitive adhesive layer (a), and pressing the thermoplastic bonding material (B) on which the heat-sensitive adhesive sheet (a) is laminated with compressed air, a pressing plate, or the like; removing the molded product of the thermoplastic bonding material (B) on which the thermosensitive adhesive sheet (a) is laminated from the molding machine and trimming the thermoplastic bonding material (B) on which the thermosensitive adhesive sheet (a) is laminated; and a step of pressing and bonding the thermoplastic bonding material (B) laminated with the heat-sensitive adhesive sheet (a) to the surface of the molded article (C) while heating the thermoplastic bonding material (B) or the molded article (C) laminated with the heat-sensitive adhesive sheet (a) at 90 to 200 ℃ using a hot press apparatus or the like.

The bonded article bonded by the bonding method has a structure in which the thermoplastic bonding material (B) and the molded article (C) are laminated via the heat-sensitive adhesive sheet (a). Further, the decorative layer and the functional layer may be laminated between the thermoplastic bonding material (B) and the heat-sensitive adhesive sheet (a) or between the heat-sensitive adhesive sheet (a) and the molded product (C), as required.

The bonded article formed by the bonding method of the present invention can be suitably used for a resin molded article used for home electric appliances, exterior trims of mobile terminals, interior and exterior trims of automobiles, and the like, in which the decorative layer and the functional layer are laminated, to impart designability and functionality to the surface of the molded article. The molded article (C) is a member that is three-dimensionally molded by injection molding, press molding, or the like, and in the above-mentioned laminate, a thermoplastic laminate (B) having a hard coat layer and a matte layer on the surface thereof is laminated on the surface of the molded article (C) by the method of the present invention for the purpose of preventing scratches, improving smoothness, or the like. As a result, the bonded product obtained by the manufacturing method including the bonding method of the present invention is a bonded product having excellent appearance quality in which bubble formation due to gas that can be generated on the surface of the molded product (C) and the surface of the thermoplastic bonding material (B), and floating and peeling of the thermoplastic bonding material (B) due to springback of the curved surface of the thermoplastic bonding material (B) and the like are suppressed, and excellent transparency is also achieved.

Examples

< Synthesis of Block copolymer (k-1) >

In a reactor degassed inside and purged with nitrogen, 1,240 parts by mass of dry toluene as a solvent was charged, and while stirring, 52.0 parts by mass of 1, 2-dimethoxyethane, 60.0 parts by mass of a toluene solution containing 40.2mmol of isobutylbis (2, 6-di-t-butyl-4-methylphenoxy) aluminum, 5.17 parts by mass of a mixed solution of 2.98mmol of sec-butyllithium and n-hexane as an anionic polymerization initiator, and 54.0 parts by mass of methyl methacrylate were sequentially added and reacted at 25 ℃ for 1 hour. In this case, the polymerization conversion of methyl methacrylate was 99.9% or more. Subsequently, the reaction solution was cooled to-30 ℃ and 220.0 parts by mass of n-butyl acrylate was added dropwise over 2 hours, followed by stirring at-30 ℃ for 5 minutes after the completion of the addition. The polymerization conversion of n-butyl acrylate at this time was 99.9% or more. Subsequently, 70.0 parts by mass of methyl methacrylate was added to the reaction solution, and after stirring overnight at 25 ℃, 3.50g of methanol was added to stop the polymerization reaction. The polymerization conversion of methyl methacrylate at this time was 99.9% or more. The obtained reaction solution was poured into a large amount of methanol, and the filtrate was vacuum-dried to obtain a triblock copolymer (k-1) composed of polymethyl methacrylate-poly (n-butyl acrylate) -polymethyl methacrylate, containing 36 mass% of polymethyl methacrylate as a polymer block having a glass transition temperature of 90 ℃ or higher (S2) and 64 mass% of poly (n-butyl acrylate) as a polymer block having a glass transition temperature of-20 ℃ or lower (S1). The weight average molecular weight (Mw) of the obtained triblock copolymer (k-1) was determined by GPC measurement by the above-described method, and the result was 82,000. Further, the glass transition temperature (Tg) of each polymer block of the triblock copolymer (k-1) was measured, and as a result, the Tg of the polymer block of polymethyl methacrylate was 103 ℃ and the Tg of the polymer block of poly-n-butyl acrylate was-51 ℃.

The glass transition temperature (Tg) of each polymer block of the block copolymer (k-1) was measured at a temperature rise rate of 10 ℃ per minute on a curve of-100 ℃ to 150 ℃ using a differential scanning calorimetry analyzer ("DSC-7020" manufactured by Hitachi high tech science systems, Ltd.), and the extrapolated glass transition start temperature was set to the glass transition temperature (Tg). Hereinafter, the glass transition temperatures (Tg) of the respective polymer blocks in the block copolymers (k-2) to (k-8) and examples and comparative examples were also measured by the above-mentioned method.

< Synthesis of Block copolymer (k-2) >

By adjusting the amounts of methyl methacrylate and n-butyl acrylate used in the same manner as in the block copolymer (k-1), a triblock copolymer (k-2) comprising polymethyl methacrylate-poly (n-butyl acrylate) -polymethyl methacrylate, containing 30 mass% of polymethyl methacrylate as the polymer block having a glass transition temperature of 90 ℃ or higher (S2) and 70 mass% of poly (n-butyl acrylate) as the polymer block having a glass transition temperature of-20 ℃ or lower (S1), was obtained. The weight average molecular weight (Mw) of the obtained triblock copolymer (k-2) was determined by GPC measurement by the above-mentioned method, and the result was 84,000. Further, the glass transition temperature (Tg) of each polymer block of the triblock copolymer (k-2) was measured, and as a result, the Tg of the polymer block of polymethyl methacrylate was 103 ℃ and the Tg of the polymer block of poly-n-butyl acrylate was-52 ℃.

< Synthesis of Block copolymer (k-3) >

By adjusting the amounts of methyl methacrylate and n-butyl acrylate used in the same manner as in the block copolymer (k-1), a triblock copolymer (k-3) comprising polymethyl methacrylate-poly (n-butyl acrylate) -polymethyl methacrylate, which comprises 40 mass% of polymethyl methacrylate as the polymer block having a glass transition temperature of 90 ℃ or higher (S2) and 60 mass% of poly (n-butyl acrylate) as the polymer block having a glass transition temperature of-20 ℃ or lower (S1), was obtained. The weight average molecular weight (Mw) of the obtained triblock copolymer (k-3) was determined by GPC measurement by the above-mentioned method, and it was 79,000. Further, the glass transition temperature (Tg) of each polymer block of the triblock copolymer (k-3) was measured, and as a result, the Tg of the polymer block of polymethyl methacrylate was 104 ℃ and the Tg of the polymer block of poly-n-butyl acrylate was-51 ℃.

< Synthesis of Block copolymer (k-4) >

By adjusting the amounts of methyl methacrylate and n-butyl acrylate used in the same manner as in the block copolymer (k-1), a triblock copolymer (k-4) comprising polymethyl methacrylate-poly (n-butyl acrylate) -polymethyl methacrylate, which comprises 50% by mass of polymethyl methacrylate as the polymer block having a glass transition temperature of 90 ℃ or higher (S2) and 50% by mass of poly (n-butyl acrylate) as the polymer block having a glass transition temperature of-20 ℃ or lower (S1), was obtained. The weight average molecular weight (Mw) of the obtained triblock copolymer (k-4) was determined by GPC measurement by the above-mentioned method, and the result was 76,000. Further, the glass transition temperature (Tg) of each polymer block of the triblock copolymer (k-4) was measured, and as a result, the Tg of the polymer block of polymethyl methacrylate was 104 ℃ and the Tg of the polymer block of poly-n-butyl acrylate was-52 ℃.

< Synthesis of Block copolymer (k-5) >

By adjusting the amounts of methyl methacrylate and n-butyl acrylate used in the same manner as in the block copolymer (k-1), a triblock copolymer (k-5) comprising polymethyl methacrylate-poly (n-butyl acrylate) -polymethyl methacrylate, which comprises 27 mass% of polymethyl methacrylate as the polymer block having a glass transition temperature of 90 ℃ or higher (S2) and 73 mass% of poly (n-butyl acrylate) as the polymer block having a glass transition temperature of-20 ℃ or lower (S1), was obtained. The weight average molecular weight (Mw) of the obtained triblock copolymer (k-5) was determined by GPC measurement by the above-described method, and the result was 83,000. Further, the glass transition temperature (Tg) of each polymer block of the triblock copolymer (k-5) was measured, and as a result, the Tg of the polymer block of polymethyl methacrylate was 103 ℃ and the Tg of the polymer block of poly-n-butyl acrylate was-53 ℃.

< Synthesis of Block copolymer (k-6) >

In a reactor degassed inside and purged with nitrogen, 2 parts by mass of a cyclohexane solution containing 5,000 parts by mass of dry cyclohexane as a solvent, 10.5% by mass of sec-butyllithium as an anionic polymerization initiator, and 28 parts by mass of tetrahydrofuran as a lewis base were charged. After the temperature was raised to 50 ℃, 70 parts by mass of styrene was added and reacted for 1 hour, 345 parts by mass of butadiene was continuously added and polymerized for 2 hours, and then 70 parts by mass of styrene was added and reacted for 1 hour, thereby obtaining a reaction solution containing a polystyrene-polybutadiene-polystyrene triblock copolymer.

To the reaction solution, 10 mass% of palladium on carbon (palladium content: 5 mass%) as a hydrogenation catalyst was added to the block copolymer, and the reaction was carried out under a hydrogen pressure of 2MPa at 150 ℃ for 10 hours.

After the mixture was allowed to stand and cooled and the pressure was released, the palladium/carbon was removed by filtration, the filtrate was concentrated and further vacuum-dried, thereby obtaining particles of a triblock copolymer (k-6) of polystyrene-hydrogenated polybutadiene-polystyrene containing 30 mass% of polystyrene as a polymer block having a glass transition temperature of 90 ℃ or higher (S2) and 70 mass% of hydrogenated polybutadiene as a polymer block having a glass transition temperature of-20 ℃ or lower (S1). The weight average molecular weight (Mw) of the obtained triblock copolymer (k-6) was determined by GPC measurement by the above-described method, and the result was 200,000. Further, the glass transition temperature (Tg) of each polymer block of the triblock copolymer (k-6) was measured, and as a result, the Tg of the polymer block of polystyrene was 97 ℃ and the Tg of the polymer block of hydrogenated polybutadiene was-23 ℃.

< Synthesis of Block copolymer (k-7) >

A triblock copolymer (k-7) of polystyrene-hydrogenated polybutadiene-polystyrene containing 67 mass% of polystyrene as a hard block (polymer block (S2) having a glass transition temperature of 90 ℃ or higher) and 33 mass% of hydrogenated polybutadiene as a polymer block (S1) having a glass transition temperature of-20 ℃ or lower) was obtained by adjusting the amounts of styrene and butadiene used in the same manner as in the block copolymer (k-6). The weight average molecular weight (Mw) of the obtained triblock copolymer (k-7) was determined by GPC measurement by the above-described method, and the result was 100,000. Further, the glass transition temperature (Tg) of each polymer block of the triblock copolymer (k-7) was measured, and as a result, the Tg of the polymer block of polystyrene was 98 ℃ and the Tg of the polymer block of hydrogenated polybutadiene was-23 ℃.

< Synthesis of acrylic random copolymer (k-8) >

In a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer, a dropping funnel and a nitrogen gas inlet, 50 parts by mass of n-butyl acrylate, 30 parts by mass of methyl methacrylate, 20 parts by mass of 2-hydroxyethyl methacrylate and 0.5 part by mass of 2, 2' -azobisisobutyronitrile as a polymerization initiator were dissolved in 150 parts by mass of ethyl acetate, and after nitrogen substitution, polymerization was carried out at 80 ℃ for 8 hours to obtain a solution of (meth) acrylic random copolymer (k-8). The weight average molecular weight (Mw) of the resulting (meth) acrylic acid random copolymer (k-8) was determined by GPC measurement by the above-mentioned method, and the result was 470,000. Further, the glass transition temperature (Tg) of the (meth) acrylic random copolymer (k-8) was measured, and as a result, no inflection point was observed.

< Synthesis of acrylic random copolymer (k-9) >

In a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer, a dropping funnel and a nitrogen gas inlet, 80 parts by mass of methyl methacrylate, 15 parts by mass of ethyl acrylate, 5 parts by mass of 2-hydroxyethyl acrylate and 0.7 part by mass of 2, 2' -azobisisobutyronitrile as a polymerization initiator were dissolved in 150 parts by mass of ethyl acetate, and after nitrogen substitution, polymerization was carried out at 85 ℃ for 10 hours to obtain a solution of (meth) acrylic random copolymer (k-9). The weight average molecular weight (Mw) of the resulting (meth) acrylic acid random copolymer (k-9) was determined by GPC measurement by the above-mentioned method, and the result was 220,000. Further, the glass transition temperature (Tg) of the (meth) acrylic random copolymer (k-9) was measured, and the Tg was 72 ℃.

(example 1)

< production of Heat-sensitive adhesive sheet (A-1) >

135 parts by mass of the triblock copolymer (k-1) was dissolved in 165 parts by mass of toluene with stirring to obtain a solution of the adhesive composition (a-1) having a solid content of 45 mass%. The content of the polymer block (S2) having a glass transition temperature of 90 ℃ or higher in the triblock copolymer was 36 parts by mass, and the content of the polymer block (S1) having a glass transition temperature of-20 ℃ or lower was 64% by mass.

The adhesive composition (a-1) was applied to the release treated surface of a 75 μm thick polyethylene terephthalate film (TN 100-75 μm manufactured by Toyo Seiko Co., Ltd.) which had been subjected to a release treatment with a non-silicone compound on one side of the release liner A on the heavy release side, and dried to a thickness of 100 μm, and dried at 70 ℃ for 3 minutes and at 120 ℃ for 4 minutes, and then bonded to the release treated surface of a 50 μm thick polyethylene terephthalate film (50E-0010 BD manufactured by Tensen Co., Ltd.) which had been subjected to a release treatment with a silicone compound on one side of the release liner B on the light release side, to produce a heat-sensitive adhesive sheet (A-1).

(example 2)

< production of Heat-sensitive adhesive sheet (A-2) >

54 parts by mass of the triblock copolymer (k-2) and 81 parts by mass of the triblock copolymer (k-3) were dissolved in 156 parts by mass of toluene with stirring to obtain a solution of the adhesive composition (a-2) having a solid content of 45 mass%. The content of the polymer block (S2) having a glass transition temperature of 90 ℃ or higher in the triblock copolymer was 36% by mass on the average, and the content of the polymer block (S1) having a glass transition temperature of-20 ℃ or lower was 64% by mass on the average. The content ratios of the polymer blocks (S1) and (S2) in the block copolymer mixture of the triblock copolymer (k-2) and the triblock copolymer (k-3) in the adhesive composition (a-2) are calculated based on the formula (1) for the content ratios of the polymer blocks (S1) and (S2) in the block copolymer mixture described in the item of the "heat-sensitive adhesive layer (a)" of the "1. heat-sensitive adhesive sheet (a)".

A heat-sensitive adhesive sheet (a-2) was produced in the same manner as in example 1, except that a solution of the adhesive composition (a-2) was used instead of the solution of the adhesive composition (a-1), and the thickness after drying was 100 μm.

(example 3)

< production of Heat-sensitive adhesive sheet (A-3) >

122 parts by mass of the triblock copolymer (k-3) and 13 parts by mass of PINECRYSTAL KE-311 (a pale rosin derivative available from Mitsukawa chemical Co., Ltd.) as a tackifier were dissolved with stirring in 156 parts by mass of toluene to obtain an adhesive composition (a-3) solution having a solid content of 45% by mass. The content of the polymer block (S2) having a glass transition temperature of 90 ℃ or higher in the triblock copolymer was 40% by mass, and the content of the polymer block (S1) having a glass transition temperature of-20 ℃ or lower was 60% by mass.

A heat-sensitive adhesive sheet (a-3) was produced in the same manner as in example 1, except that a solution of the adhesive composition (a-3) was used instead of the solution of the adhesive composition (a-1), and the thickness after drying was 100 μm.

(example 4)

< production of Heat-sensitive adhesive sheet (A-4) >

54 parts by mass of the triblock copolymer (k-2) and 81 parts by mass of the triblock copolymer (k-4) were dissolved in 156 parts by mass of toluene with stirring to obtain a solution of the adhesive composition (a-4) having a solid content of 45 mass%. The content of the polymer block (S2) having a glass transition temperature of 90 ℃ or higher in the triblock copolymer was 42% by mass on the average, and the content of the polymer block (S1) having a glass transition temperature of-20 ℃ or lower was 58% by mass. The content ratios of the polymer blocks (S1) and (S2) in the block copolymer mixture of the triblock copolymer (k-2) and the triblock copolymer (k-4) in the adhesive composition (a-4) were calculated based on the formula (1) for the content ratios of the polymer blocks (S1) and (S2) in the block copolymer mixture described in the item of the "heat-sensitive adhesive layer (a)" of the "1. heat-sensitive adhesive sheet (a)".

A heat-sensitive adhesive sheet (a-4) was produced in the same manner as in example 1, except that a solution of the adhesive composition (a-4) was used instead of the solution of the adhesive composition (a-1), and the thickness after drying was 100 μm.

(example 5)

< production of Heat-sensitive adhesive sheet (A-5) >

135 parts by mass of the triblock copolymer (k-2) was dissolved in 156 parts by mass of toluene with stirring to obtain a solution of the adhesive composition (a-5) having a solid content of 45 mass%. The content of the polymer block (S2) having a glass transition temperature of 90 ℃ or higher in the triblock copolymer was 30% by mass on average, and the content of the polymer block (S1) having a glass transition temperature of-20 ℃ or lower was 70% by mass on average.

A heat-sensitive adhesive sheet (a-5) was produced in the same manner as in example 1, except that a solution of the adhesive composition (a-5) was used instead of the solution of the adhesive composition (a-1), and the thickness after drying was 100 μm.

(example 6)

< production of Heat-sensitive adhesive sheet (A-6) >

Separately from the production of the heat-sensitive adhesive sheet (a-1) of example 1, a solution of the adhesive composition (a-1) was applied to the release treated surface of the release liner B (polyethylene terephthalate film "50E-0010 BD") used in example 1 so that the dried thickness became 100 μm, dried at 70 ℃ for 3 minutes and dried at 120 ℃ for 4 minutes, and temporarily bonded to the adhesive surface of the previously produced heat-sensitive adhesive sheet (a-1), and then bonded between the adhesive layers by a hot laminator (manufactured by Tester industries, ltd. "SA-1010 mini desk laminator test") heated to 120 ℃ at a speed of 1 m/min and a pressure of 0.2MPa to produce a heat-sensitive adhesive sheet (a-6) having an adhesive layer thickness of 200 μm.

(example 7)

< production of Heat-sensitive adhesive sheet (A-7) >

A heat-sensitive adhesive sheet (a-7) was produced in the same manner as the heat-sensitive adhesive sheet (a-1) of example 1, except that the adhesive composition (a-1) was applied so that the thickness after drying became 50 μm.

(example 8)

< production of Heat-sensitive adhesive sheet (A-8) >

108 parts by mass of the triblock copolymer (k-6) and 27 parts by mass of the triblock copolymer (k-7) were dissolved in 315 parts by mass of toluene with stirring to obtain an adhesive composition (a-8) solution having a solid content of 30 mass%. The content of the polymer block (S2) having a glass transition temperature of 90 ℃ or higher in the triblock copolymer was 37.4% by mass on average, and the content of the polymer block (S1) having a glass transition temperature of-20 ℃ or lower was 62.6% by mass on average. The content ratios of the polymer blocks (S1) and (S2) in the block copolymer mixture of the triblock copolymer (k-6) and the triblock copolymer (k-7) in the adhesive composition (a-8) were calculated based on the formula (1) for the content ratios of the polymer blocks (S1) and (S2) in the block copolymer mixture described in the item of the "heat-sensitive adhesive layer (a)" of the "1. heat-sensitive adhesive sheet (A)".

A heat-sensitive adhesive sheet (a-8) was produced in the same manner as in example 1, except that a solution of the adhesive composition (a-8) was used instead of the solution of the adhesive composition (a-1), and the thickness after drying was 100 μm.

(example 9)

< production of Heat-sensitive adhesive sheet (A-13) >

122 parts by mass of the triblock copolymer (k-1) and 13 parts by mass of YS POLYSTAR TH130 (terpene phenolic resin, manufactured by Yasuhara Chemical Co., Ltd.) as a tackifier were dissolved by stirring in 156 parts by mass of toluene to obtain a solution of the adhesive composition (a-13) having a solid content of 45 mass%. The content of the polymer block (S2) having a glass transition temperature of 90 ℃ or higher in the triblock copolymer was 36% by mass, and the content of the polymer block (S1) having a glass transition temperature of-20 ℃ or lower was 64% by mass.

A heat-sensitive adhesive sheet (a-13) was produced in the same manner as in example 1, so that the thickness after drying became 100 μm.

Comparative example 1

< production of Heat-sensitive adhesive sheet (A-9) >

135 parts by mass of the triblock copolymer (k-5) was dissolved in 156 parts by mass of toluene with stirring to obtain a solution of the adhesive composition (a-9) having a solid content of 45 mass%. The content of the polymer block (S2) having a glass transition temperature of 90 ℃ or higher in the triblock copolymer was 27% by mass, and the content of the polymer block (S1) having a glass transition temperature of-20 ℃ or lower was 73% by mass.

A heat-sensitive adhesive sheet (a-9) was produced in the same manner as in example 1, except that a solution of the adhesive composition (a-9) was used instead of the solution of the adhesive composition (a-1), and the thickness after drying was 100 μm.

Comparative example 2

< production of Heat-sensitive adhesive sheet (A-10) >

135 parts by mass of the triblock copolymer (k-4) was dissolved in 156 parts by mass of toluene with stirring to obtain a solution of the adhesive composition (a-10) having a solid content of 45 mass%. The content of the polymer block (S2) having a glass transition temperature of 90 ℃ or higher in the triblock copolymer was 50% by mass, and the content of the polymer block (S1) having a glass transition temperature of-20 ℃ or lower was 50% by mass.

A heat-sensitive adhesive sheet (a-10) was produced in the same manner as in example 1, except that a solution of the adhesive composition (a-10) was used instead of the solution of the adhesive composition (a-1), and the thickness after drying was 100 μm.

Comparative example 3

< production of Heat-sensitive adhesive sheet (A-11) >

5 parts by mass of CORONATE HXR (manufactured by Tosoh corporation, solid content 100% by mass) as an isocyanurate-based crosslinking agent was added to 100 parts by mass of the solid content of the acrylic copolymer resin (k-8), and the mixture was stirred for 20 minutes by using a stirrer, thereby obtaining an adhesive composition (a-11) solution having a solid content of 43% by mass.

A heat-sensitive adhesive sheet (A-11) was produced in the same manner as in example 1, except that a solution of the adhesive composition (a-11) was used instead of the solution of the adhesive composition (a-1), and the sheet was left to stand at 40 ℃ for 5 days so that the thickness after drying became 100. mu.m.

Comparative example 4

< production of pressure-sensitive adhesive sheet (A-12) >

A commercially available acrylic pressure-sensitive adhesive sheet (manufactured by DIC corporation, "DAITAC ZB 7012W") having a thickness of 50 μm was used. The pressure-sensitive adhesive sheet has a laminated structure of a light release liner/an acrylic pressure-sensitive adhesive layer/a heavy release liner.

Comparative example 5

< production of Heat-sensitive adhesive sheet (A-14) >

2.5 parts by mass of CORONATE HXR (100% by mass of solid content, manufactured by Tosoh corporation) as an isocyanurate-based crosslinking agent was added to 100 parts by mass of the solid content of the (meth) acrylic random copolymer resin (k-9), and the mixture was stirred with a stirrer for 20 minutes to obtain an adhesive composition (a-14) solution having a solid content of 42% by mass.

A heat-sensitive adhesive sheet (A-14) was produced in the same manner as in example 1, except that a solution of the adhesive composition (a-14) was used instead of the solution of the adhesive composition (a-1), and the sheet was left to stand at 40 ℃ for 5 days so that the thickness after drying became 100. mu.m.

< production of thermoplastic adhesive Material (B-1) >

A commercially available polycarbonate sheet (manufactured by Diko K.K., "Panlite PC-2151") having a thickness of 0.3mm was cut into a size suitable for each evaluation and used.

< production of thermoplastic adhesive Material (B-2)

A commercially available polycarbonate sheet (manufactured by Diyu corporation, "Panlite PC-2151") having a thickness of 0.125mm was cut into a size suitable for each evaluation and used.

< production of molded article (C-1) >

A commercially available polycarbonate molded article (manufactured by Diyu corporation, manufactured by Sumitomo Bakelite, manufactured by POLICAACE ECK100 UU) having a thickness of 3mm was cut into a size suitable for each evaluation and used.

(method of measuring tensile storage modulus and loss tangent)

The release liners were removed from the adhesive sheets obtained in the above examples and comparative examples in order and laminated to a thickness of 600 μm, and then the sheets were allowed to stand in a dryer at 120 ℃ for 30 seconds to thermally bond the layers. The test piece was made in a rectangular shape by making the width 5mm and the length of the measuring part 20mm, and cutting the lengths of the handles at both ends 20mm each. The release liners on both sides were peeled off and removed, and a dynamic viscoelasticity measuring apparatus (RSA III, TA instruments) was used at a temperature rising rate of 5 ℃/min and a measuring frequency of 3.0Hz, a measurement temperature range of-50 to 200 ℃ and tensile storage modulus (E ') at-20 ℃, 25 ℃, 100 ℃ and 150 ℃ respectively'_a-20、E’_a25、E’_a100、E’_a150) And loss tangent (tan δ). From the obtained graph of loss tangent (tan δ), the presence or absence of the peak temperature and the loss tangent (tan δ) at the temperature and the peak temperature were read.

(evaluation method of foaming resistance and peeling resistance in application)

The adhesive sheets obtained in the above examples and comparative examples were cut into a size of 30cm square, the release liner B (PET film "50E-0010 BD) of the adhesive sheets of examples 1 to 9 and comparative examples 1 to 3 and 5 or the release liner on the light release side of the adhesive sheet used in comparative example 4 was removed, the adhesive sheet was temporarily bonded to a thermoplastic bonding material (B-1) having the same size by a manual roll, and then the adhesive sheet was thermally bonded to the thermoplastic bonding material (B-1) by a thermal laminator (manufactured by Tester industries co., ltd." SA-1010 small bench test laminator ") heated to 120 ℃ at a speed of 1 m/min and a pressure of 0.2 MPa.

Next, the sample was cut into a 10cm square, the release liner on the remaining one side was removed, and the sample was placed on the surface of a molded article (C-1) having a size of 12cm square and placed on a hot Press apparatus (thermo-Press "TP-750 Air Press" manufactured by Tester industries, Ltd.), and only the surface side of the thermoplastic bonding material (B-1) was heated at 140 ℃ for 15 seconds under a pressure of 0.2MPa, whereby the sample was heat-sensitive bonded to the surface of the molded article (C-1), thereby obtaining a bonded article.

In comparative example 4, a pressure-sensitive adhesive sheet was used, and a patch was produced under the same conditions as described above. In the following evaluations, unless otherwise specified, a patch was produced under the same conditions as in the other examples and comparative examples and used.

The appearance of the obtained patch was visually evaluated according to the following criteria.

< evaluation of foaming resistance and peeling resistance at the time of adhesion >

Very good: there were no fine bubbles or peeling at all.

Good: there were few fine bubbles or peeling, but the level was no problem in appearance.

X: the appearance was poor due to bubbles or peeling.

(evaluation method of foaming resistance and peeling resistance after leaving in high-temperature humid atmosphere)

Next, the above-mentioned sticker was left to stand at 85 ℃ and 85% RH for 250 hours, and then the change in appearance of the sticker was visually evaluated based on the same criteria as described above.

< evaluation of foaming resistance and peeling resistance after leaving in high-temperature and humid Environment >

Very good: there was no increase in micro bubbles or peeling at all compared to before placement.

Good: there was little increase in minute bubbles or peeling compared to before standing, but at a level that was not problematic in appearance.

X: the bubbles or peeling increased and the appearance was poor as compared with that before the setting.

(evaluation method of foaming resistance and peeling resistance after leaving in Cold and Hot Environment)

The above-mentioned adherend was left to stand at a temperature of-20 ℃ for 30 minutes and then at a temperature of 85 ℃ for 30 minutes, and after repeating the above-mentioned conditions 250 times, the appearance of the adherend was visually evaluated according to the same criteria as the evaluation methods of the foaming resistance and the peeling resistance after the above-mentioned high-temperature and high-humidity environment was left to stand.

(method of evaluating the size of the domain of the Polymer Block (S2))

The phase separation pattern was visually confirmed by scanning an image obtained by scanning an arbitrary position on the adhesive surface of the adhesive sheet obtained in the above examples and comparative examples over a field of view of 1 μm using the phase mode of a Scanning Probe Microscope (SPM). Further, the long side lengths of the domains formed by the polymer block (S2) at arbitrary 5 points or more were measured and averaged to set the domain size of the polymer block (S2). The measurement was performed in a proximity contact mode using "Nano-DST" manufactured by Pacific Nanotechnology Co.Ltd as a scanning probe microscope.

(method of evaluating peel adhesion immediately after application)

The adhesive sheets obtained in examples and comparative examples were cut into 30cm square pieces, the release liner B (PET film "50E-0010 BD") of the adhesive sheets of examples 1 to 9 and comparative examples 1 to 3 and 5 or the release liner on the light release side of the adhesive sheet used in comparative example 4 was removed, the sheets were temporarily bonded to a thermoplastic bonding material (B-2) having the same size using a hand roller, and the adhesive sheets were heat-sensitive bonded to the thermoplastic bonding material (B-2) by the above thermal laminator heated to 120 ℃ at a speed of 1 m/min and a pressure of 0.2 MPa.

Next, the above sample was cut into a width of 1cm and a length of 10cm, the release liner on the remaining one side was removed under an environment of 23 ℃ and 50% RH, the sample was placed on the surface of a molded article (C-1) cut into a size of 2cm and a length of 12cm, 1 reciprocal pressing was performed with a 2kg roller, and the peel resistance was measured when the thermoplastic adhesive material (B-2) on which the adhesive sheet was laminated was directly stretched in a 180 ° direction at a stretching speed of 50 mm/min for 1 minute by a tensillon type tensile tester (manufactured by a & D, RTG-1210) equipped with a thermostatic bath under the above environment.

When peeling occurs due to the stick-slip phenomenon, the average value of the peaks of intermittent peeling resistance is defined as the peeling adhesion force.

(method of evaluating Peel Adhesion after Heat bonding)

Similarly to the evaluation of the peel adhesion immediately after the application, the sheet was cut into a width of 1cm and a length of 10cm, the remaining release liner was removed under a temperature environment of 23 ℃ and a relative humidity of 50% RH, the sheet was placed on the surface of a molded article (C-1) cut into a size of 2cm in width and 12cm in length, and then the sheet was placed in the hot press apparatus, and only the surface side of the thermoplastic adhesive material (B-2) was heated at 140 ℃ for 15 seconds under a pressure of 0.2MPa to heat-bond the sample to the surface of the molded article (C-1) to obtain an adhesive. The obtained bonded product was measured for peel resistance in an atmosphere of 23 ℃ after heat bonding in the same manner as the evaluation of peel adhesion immediately after bonding. A patch was produced in the same manner as described above, and the peel resistance was measured at 90 ℃ and-20 ℃.

(method of evaluating embeddability of Metal wire)

The adhesive sheets obtained in the above examples and comparative examples were cut into 30cm square pieces, the release liner B (PET film "50E-0010 BD) of the adhesive sheets of examples 1 to 9 and comparative examples 1 to 3 and 5 or the release liner on the light release side of the adhesive sheet used in comparative example 4 was removed, and the sheets were temporarily bonded to a thermoplastic bonding material (B-1) of the same size by hand mixing, and then the heat-sensitive adhesive sheet was bonded to the thermoplastic bonding material (B-1) by the above thermal laminator heated to 120 ℃ at a speed of 1 m/min and a pressure of 0.2 MPa.

Then, the sample was cut into a 10cm square, the release liner on the remaining one side was removed, 5 polyurethane copper wires (UEW, manufactured by triplex photonics corporation) having a diameter of 0.2mm, which were cut into a length of 12cm, were placed on the surface of the adhesive layer at equal intervals, and the sample was heated from the thermoplastic bonding material (B-1) side at a pressure of 0.2MPa for 15 seconds at 140 ℃. Further, when the embedding rate exceeds 25%, the value is "O", and when not exceeding, the value is "X".

Burying rate [% ] is the reduced thickness [ μm ] before and after hot pressing/thickness [ μm ] x 100 of adhesive sheet

(evaluation method of ease of correction of sticking position)

The adhesive sheets obtained in examples and comparative examples were cut into a size of 30cm square, the release liner on one side was removed, and the sheet was temporarily bonded to a thermoplastic bonding material (B-2) having the same size by a hand roll, and then the adhesive sheet was heat-sensitive bonded to the thermoplastic bonding material (B-2) by the above thermal laminator heated to 120 ℃ at a speed of 1 m/min and a pressure of 0.2 MPa.

Subsequently, the plate was cut into a size of 5cm square, placed on a stainless steel plate of SUS304 having a thickness of 1mm and subjected to bright annealing at a temperature of 23 ℃ and a relative humidity of 50% RH, and pressed at a speed of 300 mm/min by a 2kg roller for 1 round trip. After 1 minute, the adhesive sheet was peeled off by hand in the direction of 90 ° at a stretching speed of about 1 m/minute, and the ease of peeling off the thermoplastic adhesive material (B-2) on which the adhesive sheet was laminated was evaluated as the ease of correction of the sticking position.

< evaluation of ease of correction of sticking position >

Very good: peeling was easy and no deformation of the thermoplastic bonding material (B-2) was observed.

Good: the peeling was slightly heavy, but no deformation of the thermoplastic bonding material (B-2) was observed.

X: the peeling was heavy, and the thermoplastic bonding material (B-2) was deformed.

(method of measuring Total light transmittance Tt and haze)

Regarding the total light transmittance Tt and the haze, the release liners on both sides of the adhesive sheets obtained in examples and comparative examples were removed, and the total light transmittance Tt and the haze were measured using "HR-100 type" manufactured by color technology research on kamura.

[ Table 1]

[ Table 2]

[ Table 3]

[ Table 4]

[ Table 5]

[ Table 6]

[ Table 7]

[ Table 8]

In the heat-sensitive adhesive sheets obtained in examples 1 to 9, in the step of heating the thermoplastic bonding material on which the heat-sensitive adhesive sheet was laminated to 140 ℃ and bonding the same to the surface of the molded article, bubble formation and peeling of the thermoplastic bonding material due to gas that can be generated from the thermoplastic bonding material were suppressed, and a laminate excellent in appearance was formed. Further, even when these laminates are placed in a high-temperature and high-humidity environment, bubble formation and peeling caused by gas that can be generated from at least one of the thermoplastic bonding material and the molded product can be suppressed, and furthermore, even when the laminates are placed in an environment where cooling and heating are repeated, floating and peeling between the thermoplastic bonding material and the molded product can be suppressed, and excellent appearance can be maintained.

On the other hand, in the heat-sensitive adhesive sheets and pressure-sensitive adhesive sheets obtained in comparative examples 1, 3, and 4, the tensile storage modulus at 100 ℃ was lower than the predetermined range, and in the step of heating the thermoplastic bonding material on which the adhesive sheet was laminated to 140 ℃ and bonding the same to the surface of the molded article, bubble formation and peeling of the thermoplastic bonding material due to gas that can be generated from the thermoplastic bonding material occurred, and the laminates had poor appearance. The heat-sensitive adhesive sheet obtained in comparative example 2 had a tensile storage modulus at 100 ℃ higher than a predetermined range, and although no bubble was formed in the above-mentioned bonding step, bubble formation and peeling occurred when it was left in an environment of repeated cooling and heating, and it was a poor-looking adhesive. The heat-sensitive adhesive sheet obtained in comparative example 5 had a tensile storage modulus at 100 ℃ in a predetermined range, but had no peak tensile loss tangent (tan δ) temperature in a temperature range of-20 ℃ or less, and when placed in an environment of repeated cooling and heating, bubble formation and peeling occurred, resulting in a poor appearance of the adhesive sheet.

Description of the symbols

1 microdomains of the Polymer Block (S1)

2 microdomains of the polymer block (S2).

Claims

1. A heat-sensitive adhesive sheet comprising a heat-sensitive adhesive layer (a) having a peak temperature of tensile loss tangent (tan delta) measured at a frequency of 3Hz within the range of-50 ℃ to 200 ℃ of at least one or more at 90 ℃ and at least one or more at-20 ℃ and a tensile storage modulus (E ') at 100 ℃'_a100) Is 5 x 10⁵Pa～1×10⁸Pa，

The heat-sensitive adhesive sheet is used for bonding the thermoplastic bonding material (B) to the surface of the molded product (C) using the heat-sensitive adhesive layer (a) as an adhesive layer.

2. The heat-sensitive adhesive sheet according to claim 1, wherein the heat-sensitive adhesive layer (a) contains a block copolymer having a polymer block (S1) and a polymer block (S2), the polymer block (S1) has a glass transition temperature of-20 ℃ or lower, and the polymer block (S2) has a glass transition temperature of 90 ℃ or higher.

3. The heat-sensitive adhesive sheet according to claim 2, wherein the content of the polymer block (S2) in the block copolymer is 29 to 49% by mass.

4. The heat-sensitive adhesive sheet according to any one of claims 1 to 3, wherein the heat-sensitive adhesive layer (a) contains a block copolymer having a domain size of 160nm or more on average, the domain size being formed by a polymer block (S2) having a glass transition temperature of 90 ℃ or higher.

5. The heat-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the heat-sensitive adhesive layer (a) contains a triblock copolymer having a polymer block (S1) and a polymer block (S2), the polymer block (S1) having a glass transition temperature of-20 ℃ or lower, and the polymer block (S2) having a glass transition temperature of 90 ℃ or higher.

6. The heat-sensitive adhesive sheet according to any one of claims 1 to 5, wherein the heat-sensitive adhesive layer (a) has a thickness in the range of 10 to 300 μm.

7. The heat-sensitive adhesive sheet according to any one of claims 1 to 6, wherein the thickness of the thermoplastic bonding material (B) is 0.05mm to 5 mm.

8. The heat-sensitive adhesive sheet according to any one of claims 1 to 7, wherein at least one of the thermoplastic bonding material (B) and the molded product (C) is an adherend capable of generating gas when left standing at a temperature of 85 ℃ and a relative humidity of 85% RH for 24 hours.

9. The heat-sensitive adhesive sheet according to any one of claims 1 to 8, wherein a decorative layer or a metal-processed layer having a thickness of 35% or less of the thickness of the heat-sensitive adhesive sheet is laminated between the heat-sensitive adhesive layer (a) and the thermoplastic bonding material (B) or between the heat-sensitive adhesive layer (a) and the molded article (C).

10. A method for producing an article, in which a thermoplastic bonding material (B) is bonded to the surface of a molded article (C) using the heat-sensitive adhesive layer (a) of the heat-sensitive adhesive sheet according to any one of claims 1 to 9 as an adhesive layer, the method comprising:

a step [1] of bonding the thermosensitive adhesive layer (a) of the thermosensitive adhesive sheet to the thermoplastic bonding material (B) to form a laminate; and

and (2) after the step (1), heating the thermoplastic bonding material (B) or the thermosensitive adhesive layer (a) to 90 to 200 ℃, and bonding the thermosensitive adhesive layer (a) of the laminate and the molded article (C) by pressing.

11. A method for producing an article, in which a thermoplastic bonding material (B) is bonded to the surface of a molded article (C) using the heat-sensitive adhesive layer (a) of the heat-sensitive adhesive sheet according to any one of claims 1 to 9 as an adhesive layer, the method comprising:

a step [3] of heating the thermosensitive adhesive layer (a) of the thermosensitive adhesive sheet to 90 to 200 ℃ and pressing and adhering the thermosensitive adhesive layer (a) of the thermosensitive adhesive sheet (A) and the molded article (C); and

and (4) heating the thermoplastic bonding material (B) to 90 to 200 ℃ after the step (3), and bonding the thermoplastic bonding material (B) and the heat-sensitive adhesive layer (a) by pressing.

12. A method for producing an article, in which a thermoplastic bonding material (B) is bonded to the surface of a molded article (C) using the heat-sensitive adhesive layer (a) of the heat-sensitive adhesive sheet according to any one of claims 1 to 9 as an adhesive layer, the method comprising:

a step [1] of bonding the thermosensitive adhesive layer (a) of the thermosensitive adhesive sheet to the thermoplastic bonding material (B) to form a laminate;

a step [5] of, after the step [1], heating the thermoplastic bonding material (B) or the thermosensitive adhesive layer (a) of the laminate to 90 to 200 ℃ and pressing the same with a mold box of the same type as the molded article (C) to mold the laminate into the shape of the molded article (C); and

and (6) covering the molded article (C) with the molded laminate, heating the heat-sensitive adhesive layer (a) from at least one of the thermoplastic adhesive material (B) and the molded article (C) to 90 to 200 ℃, and adhering the heat-sensitive adhesive layer (a) to the molded article (C).