JP2010161167A - Adhesive tape and method of manufacturing laminate including the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat-resistant adhesive tape that does not contain silicone and can be manufactured at a relatively low cost. <P>SOLUTION: A method of manufacturing a laminate that includes a carrier substrate for a printed circuit board and an adhesive tape for temporarily fixing a printed circuit board to the carrier substrate includes: forming a first adhesive layer containing a specific copolymer obtained by copolymerizing monomers containing a (meth)acrylic acid and a glycidyl (meth)acrylate; forming a second adhesive layer containing a specific copolymer obtained by copolymerizing monomers containing a (meth)acrylic acid and a glycidyl (meth)acrylate; forming an adhesive tape that includes the first adhesive layer and the second adhesive layer as the most outer layers; laminating the second adhesive layer of the adhesive tape to the carrier substrate, with the first adhesive layer of the adhesive tape being the most upper layer; and crosslinking the second adhesive layer and the first adhesive layer on the carrier substrate. The adhesive tape is a multilayer adhesive tape or a double-sided adhesive tape. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pressure-sensitive adhesive tape including a heat-resistant double-sided pressure-sensitive adhesive tape or a multilayer pressure-sensitive adhesive tape, and a method for producing a laminate including such a pressure-sensitive adhesive tape.

  In the process of manufacturing a printed wiring board such as a flexible printed wiring board, or in the process of mounting electronic components on the surface of such a printed wiring board, the surface is used for the purpose of temporarily fixing the wiring board and facilitating handling. A holding and conveying jig partially laid with an adhesive or the like is widely used. Since such a jig is usually subjected to a high-temperature treatment such as a solder reflow process, heat resistance is required.

  Patent Document 1 (Japanese Patent Application Laid-Open No. 2007-266558) discloses a heat-resistant base material layer, a weak adhesive layer that is laminated on one surface of the base material layer and holds the wiring board in a detachable manner, and a base material layer. A pressure-sensitive adhesive layer laminated on the other side of the adhesive layer, and the weak adhesive layer obtained by sticking a silicone resin with a liquid silicone resin and heat-curing the adhesive sheet, and the adhesive sheet on the surface A fixing jig for a wiring board bonded and fixed is described.

  Patent Document 2 (Japanese Patent Application Laid-Open No. 2004-158477) describes a holding and conveying jig having a fluororesin layer on the surface of a plate on which a printed wiring board or the like is placed and held.

  Furthermore, Patent Document 3 (Japanese Patent Application Laid-Open No. 2005-53975) describes a heat-resistant tape using an adhesive polymer obtained from a monomer containing alkyl (meth) acrylate, glycidyl (meth) acrylate and (meth) acrylic acid. Yes. The heat-resistant tape is a lead frame masking tape provided with the above-mentioned adhesive polymer layer on one surface of a heat-resistant substrate.

JP 2007-266558 A JP 2004-158477 A JP-A-2005-53975

  As the adhesive, a silicone resin is generally used from the viewpoint of heat resistance. However, the low molecular weight siloxane remains in the silicone resin even after polymerization, and when heated, this low molecular weight siloxane has a property of being exposed on the resin surface. Therefore, when the wiring board is placed on the surface of the resin layer and heated while being held, the low molecular weight siloxane is exposed on the resin surface and transferred to the conductive pattern on the surface of the wiring board. In this case, there is a problem that the electronic component cannot be satisfactorily bonded to the portion where the siloxane is transferred, resulting in poor bonding. In addition, siloxane is not allowed to be mixed in hard disk related parts because it causes failure.

  On the other hand, fluorine-based materials are not contaminated by silicone and are excellent in terms of durability, but the price of the materials themselves is high, and it takes labor and cost to accurately apply to a predetermined shape by screen printing or other methods. In addition, since it is difficult to remove from the holding and conveying jig after use, there is a problem that the expensive holding and conveying jig cannot be reused.

  For this reason, it is a heat-resistant double-sided adhesive tape or multilayer adhesive tape suitable for adhesion / peeling to a printed wiring board and a holding and conveying jig for the purpose of temporarily fixing and conveying the printed wiring board, and does not contain silicone, and There is a need for a heat-resistant adhesive tape that can be produced at a relatively low cost.

The present invention, according to one aspect,
A carrier substrate for a printed wiring board, and a method for producing a laminate including an adhesive tape for temporarily fixing the printed wiring board to the carrier substrate,
A first pressure-sensitive adhesive layer containing a copolymer of monomers including the following (a) to (c), having a glass transition temperature (Tg) before crosslinking of −65 ° C. or higher and lower than −30 ° C. is formed. thing,
Forming a second pressure-sensitive adhesive layer containing a copolymer of monomers containing the following (a) to (c) having a glass transition temperature (Tg) before crosslinking of -30 ° C or higher and 0 ° C or lower;
Forming an adhesive tape comprising the first adhesive layer and the second adhesive layer as outermost layers,
Bonding the second pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape to a carrier substrate, placing the first pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape as an uppermost layer, and
Cross-linking the second pressure-sensitive adhesive layer and the first pressure-sensitive adhesive layer on the carrier substrate, and the pressure-sensitive adhesive tape is a multilayer pressure-sensitive adhesive tape or a double-sided pressure-sensitive adhesive tape,
(A) alkyl (meth) acrylate having 1 to 12 carbon atoms in the alkyl group: 90 to 99 parts by mass,
(B) (meth) acrylic acid: 1 to 10 parts by mass,
(C) Glycidyl (meth) acrylate: 0.5 to 2.5 moles relative to 1.0 mole of (meth) acrylic acid (b),
The manufacturing method of the laminated body which is is provided.

According to another aspect, the present invention provides:
A carrier substrate for a printed wiring board, and a method for producing a laminate including an adhesive tape for temporarily fixing the printed wiring board to the carrier substrate,
A second pressure-sensitive adhesive layer containing a copolymer of monomers containing the following (a) to (c) having a glass transition temperature (Tg) before cross-linking of not lower than −30 ° C. and not higher than 0 ° C. on the carrier substrate: Pasted on, then
The first pressure-sensitive adhesive layer containing a copolymer of monomers containing the following (a) to (c), having a glass transition temperature (Tg) before crosslinking of −65 ° C. or higher and lower than −30 ° C. Affixing on the second adhesive layer, and
Cross-linking the second pressure-sensitive adhesive layer and the first pressure-sensitive adhesive layer on the carrier substrate,
(A) alkyl (meth) acrylate having 1 to 12 carbon atoms in the alkyl group: 90 to 99 parts by mass,
(B) (meth) acrylic acid: 1 to 10 parts by mass,
(C) Glycidyl (meth) acrylate: 0.5 to 2.5 moles relative to 1.0 mole of (meth) acrylic acid (b),
The manufacturing method of the laminated body which is is provided.

According to yet another aspect, the present invention provides:
A first pressure-sensitive adhesive layer containing a copolymer of monomers containing the following (a) to (c), wherein the glass transition temperature (Tg) before crosslinking is −65 ° C. or higher and lower than −30 ° C .;
A second pressure-sensitive adhesive layer containing a copolymer of monomers containing the following (a) to (c), wherein the glass transition temperature (Tg) before crosslinking is -30 ° C or higher and 0 ° C or lower;
Each of which is an adhesive tape for temporarily fixing a printed wiring board to a carrier substrate,
(A) alkyl (meth) acrylate having 1 to 12 carbon atoms in the alkyl group: 90 to 99 parts by mass,
(B) (meth) acrylic acid: 1 to 10 parts by mass,
(C) Glycidyl (meth) acrylate: A crosslinkable pressure-sensitive adhesive tape that is 0.5 to 2.5 moles per 1.0 mole of (meth) acrylic acid (b) is provided.

The term “(meth) acrylate” used in the present specification means acrylate or methacrylate, and “(meth) acryl” means acryl or methacryl. The term “adhesive tape” is interpreted in a broad sense including films, sheets, tapes and the like having an adhesive on at least a part of each surface.
In addition, the “adhesive tape” includes a double-sided pressure-sensitive adhesive tape having a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer on both sides of the support layer, and a support layer without the first pressure-sensitive adhesive layer and the first pressure-sensitive adhesive layer. There is a multilayer pressure-sensitive adhesive tape (also referred to as “multi-layer transfer pressure-sensitive adhesive tape”) formed by laminating two pressure-sensitive adhesive layers.
In addition, the “glass transition temperature (Tg)” in this specification refers to the FOX calculation formula (TG Fox, Bulletin of the American Physical Society ( Ser. II), 1 (3) 123 (1956) (Equation 1).
1 / Tg (copolymer) = W ₁ / Tg ₁ + W ₂ / Tg ₂ + W ₃ / Tg ₃ ... W _i / Tg _i ... + W _n / Tg _n (Formula 1).
(Wherein Tg (copolymer) is the glass transition temperature (° K) of the copolymer of n types of monomers, W _i is the weight fraction of monomer (i), and Tg _i is monomer (i ) Is the Tg (° K) of the homopolymer, and W ₁ +... + W _i ... + W _n = 1)

Since the adhesive tape of the present invention does not contain silicone, the printed wiring board is not contaminated by low molecular weight siloxane.
The adhesive has heat resistance, and no adhesive residue occurs when the printed wiring board is peeled from the adhesive tape or the adhesive tape is peeled off from the holding and conveying jig, that is, the carrier substrate.
The pressure-sensitive adhesive is an acrylic pressure-sensitive adhesive, and can be manufactured at a lower cost than a fluorine-based material.

The present invention will be described with reference to preferred embodiments.
As described above, in one embodiment, the present invention is a method for producing a laminate including a carrier substrate for a printed wiring board and a double-sided adhesive tape for temporarily fixing the printed wiring board to the carrier substrate. In this embodiment, the pressure-sensitive adhesive tape is formed as a cross-linkable double-sided pressure-sensitive adhesive tape that includes a first pressure-sensitive adhesive layer on one side of the heat-resistant support layer and includes the second pressure-sensitive adhesive layer on the opposite side. . First, a heat-resistant support layer is prepared, and a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer containing an acrylic copolymer containing glycidyl (meth) acrylate and (meth) acrylic acid as monomer units on both sides thereof. To form an uncrosslinked double-sided pressure-sensitive adhesive tape. The second pressure-sensitive adhesive layer is attached to the carrier substrate, and in this state, the copolymer is crosslinked between the glycidyl group and the carboxylic acid group of the copolymer constituting the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer. Cause a reaction. Thereby, while improving the adhesive force with respect to the carrier base material of a 2nd adhesive layer, the adhesive force with respect to the printed wiring board of a 1st adhesive layer is stabilized.

Moreover, this invention is a manufacturing method of the laminated body containing the multilayer adhesive tape for temporarily fixing the carrier base material for printed wiring boards, and a printed wiring board to a carrier base material according to another embodiment.
In one embodiment of the method for producing such a laminate, the multilayer adhesive tape is formed on a carrier substrate. An uncrosslinked second pressure-sensitive adhesive layer is formed, the second pressure-sensitive adhesive layer is attached onto a carrier substrate, an uncrosslinked first pressure-sensitive adhesive layer is formed, and the first pressure-sensitive adhesive layer is Of the copolymer which is placed on the second pressure-sensitive adhesive layer and constitutes both pressure-sensitive adhesive layers (the first pressure-sensitive adhesive layer on the printed wiring board side and the second pressure-sensitive adhesive layer on the carrier substrate side) It is manufactured by performing a crosslinking reaction.

  Further, the multilayer adhesive tape may be formed in advance, in which case the first adhesive layer and the second adhesive layer are respectively formed on the peeled substrate, and the first adhesive It is obtained by laminating so that the layer and the second pressure-sensitive adhesive layer are in contact with each other. Thereafter, the second pressure-sensitive adhesive layer is attached to the carrier base material, and a laminate containing a multilayer pressure-sensitive adhesive tape can be produced on the carrier base material by performing the same treatment as above.

The first pressure-sensitive adhesive layer on the printed wiring board side is obtained by copolymerizing monomers including the following (a) to (c), and has a glass transition temperature (Tg) before crosslinking of −65 ° C. or more and Includes copolymers that are below -30 ° C.
(A) alkyl (meth) acrylate having 1 to 12 carbon atoms in the alkyl group: 90 to 99 parts by mass,
(B) (meth) acrylic acid: 1 to 10 parts by mass,
(C) Glycidyl (meth) acrylate: 0.5 to 2.5 mol per 1.0 mol of (meth) acrylic acid (b).

  When the above-mentioned monomer composition is used, heat resistance and peelability after use can be realized. That is, in 100 parts by mass of the monomers (a) and (b), (b) (meth) acrylic acid is 1 to 10 parts by mass, and 0.5% of 1.0 mol of (meth) acrylic acid (b). When ~ 2.5 mol of glycidyl (meth) acrylate (c) is present, it exhibits cohesive force due to a crosslinking reaction between the carboxylic acid group of monomer (b) in the pressure-sensitive adhesive layer and the glycidyl group of monomer (c). To do.

  When the copolymer constituting the pressure-sensitive adhesive layer is the above-described Tg, a pressure-sensitive adhesive layer having a low adhesive force to the printed wiring board and sufficient cohesive force can be obtained. If Tg is too high, even after cross-linking, the adhesive strength to the printed wiring board becomes too strong, and if Tg is too low, the cohesive force decreases and adhesive residue may be left on the printed wiring board at the time of peeling. is there.

Tg can be controlled under the following conditions depending on the types and amounts of the monomers (a), (b) and (c).
That is, the “glass transition temperature (Tg)” in this specification is a formula for calculating FOX based on the glass transition temperature of a homopolymer of a monomer and the copolymerization ratio of the monomer (TG Fox, Bulletin of the American Physical Society ( Ser. II), 1 (3) 123 (1956)) (Equation 1). Here, the formula for calculating the FOX is for calculating the Tg of the copolymer based on the Tg of the homopolymer of each monomer constituting the copolymer. .

The monomer homopolymer Tg used for the calculation is, for example, the polymer handbook (John Willey & Sons “Polymer Handbook” 4 ^th edition (Editor: J. Brandrup, EHImmergut, EAGrulke) Wiley-Interscience (1999/2/22) page. VI / 198-VI / 205). Representative monomer homopolymers Tg are shown in Table 1 below.

  The first pressure-sensitive adhesive layer temporarily fixes the printed wiring board to the carrier substrate via a second pressure-sensitive adhesive layer (with or without a support layer between these pressure-sensitive adhesive layers). Thus, for example, the conveyance at the time of a subsequent process such as a solder reflow process is facilitated. This pressure-sensitive adhesive layer has, for example, an adhesive force with respect to a printed wiring board of 0.05 N / 10 mm or more. When the adhesive strength is less than 0.05 N / 10 mm, the printed wiring board cannot be sufficiently fixed, and the printed wiring board may be displaced or peeled off during the transportation / process. The pressure-sensitive adhesive layer has, for example, an adhesive force with respect to a printed wiring board of 0.4 N / 10 mm or less. When the adhesive strength exceeds 0.4 N / 10 mm, the printed wiring board may be damaged such as bending or curling when it is peeled off after completion of the process. In this specification, the “adhesive strength” with respect to the printed wiring board is 180 ° at a peeling speed of 300 mm / min at 25 ° C. with the printed wiring board attached to the adhesive tape by reciprocating the 2 kg roller once at 25 ° C. It means 180 degree peel adhesive force when peeled at an angle of.

The second pressure-sensitive adhesive layer on the carrier substrate side is copolymerized with monomers containing the following (a) to (c), and the glass transition temperature (Tg) before crosslinking is −30 ° C. or higher and 0 ° C. or lower. Including copolymers.
(A) alkyl (meth) acrylate having 1 to 12 carbon atoms in the alkyl group: 90 to 99 parts by mass,
(B) (meth) acrylic acid: 1 to 10 parts by mass,
(C) Glycidyl (meth) acrylate: 0.5 to 2.5 mol per 1.0 mol of (meth) acrylic acid (b).

  When the above-mentioned monomer composition is used, heat resistance and peelability after use can be realized. That is, in 100 parts by weight of the monomers (a) and (b), (b) (meth) acrylic acid is 1 to 10 parts by weight, and 0.5% of 1.0 mole of (meth) acrylic acid (b). When ~ 2.5 mol of glycidyl (meth) acrylate (c) is present, it exhibits cohesive force due to a crosslinking reaction between the carboxylic acid group of monomer (b) in the pressure-sensitive adhesive layer and the glycidyl group of monomer (c). To do.

When the copolymer constituting the pressure-sensitive adhesive layer is the above-mentioned Tg, it can be a pressure-sensitive adhesive layer having an initial adhesive force to the carrier substrate and a peelability after use. If the Tg is too high, the initial adhesive force is insufficient, making pasting difficult, and if the Tg is too low, the adhesive force to the carrier substrate may be too low.
In addition, Tg of a copolymer is calculated | required by the calculation formula (Formula 1) of FOX as above-mentioned.

  The second pressure-sensitive adhesive layer fixes the printed circuit board to the carrier substrate via the first pressure-sensitive adhesive layer. Here, in a high temperature treatment such as a solder reflow process, the carrier substrate is made of aluminum, stainless steel, glass, glass epoxy substrate, or the like. This second pressure-sensitive adhesive layer has, for example, an adhesive force (after crosslinking) to the carrier substrate of 0.8 N / 10 mm or more. When the adhesive strength is less than 0.8 N / 10 mm, the adhesive strength of the adhesive tape to the carrier substrate becomes insufficient, and when the printed wiring board is peeled from the adhesive tape, the adhesive tape is peeled off from the carrier substrate. May end up.

  Moreover, this 2nd adhesive layer has the adhesive force (after bridge | crosslinking) with respect to a carrier base material of 20 N / 10mm or less, for example. In particular, in the case of double-sided tape, if the adhesive strength exceeds 20 N / 10 mm, the support layer of the double-sided tape may be damaged when the tape is removed from the carrier base material. May be left undesired. Moreover, it is easy to peel a double-sided adhesive tape by hand force. In this specification, the “adhesive strength” for the carrier substrate means that the sample attached with the adhesive tape by reciprocating the 2 kg roller at 25 ° C. is transferred to the carrier tape at 25 ° C. at a peeling speed of 300 mm / min. It means 90 ° peel adhesive strength (N / 10 mm) when peeled from the substrate at an angle of 90 °.

  The thickness of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer is, for example, 0.5 μm or more. If it is less than 0.5 μm, the adhesion to the adherend becomes insufficient and may be peeled off during use. Moreover, the thickness of a 1st adhesive layer and a 2nd adhesive layer is 100 micrometers or less, for example. When the thickness exceeds 100 μm, the solvent used in the production remains in the pressure-sensitive adhesive, which may volatilize and foam during the heat treatment.

Below, an example of the manufacturing method of the crosslinkable double-sided adhesive tape which has the adhesive layer before bridge | crosslinking on both surfaces of a heat resistant support layer is demonstrated.
First, the above monomer mixture is polymerized. The monomer mixture can generally be radically polymerized under a polymerization initiator based on an azo compound or a peroxide. As the polymerization method, a solution polymerization method, an emulsion polymerization method, a suspension polymerization method, a bulk polymerization method, or other well-known and conventional polymerization methods can be used. The solution polymerization method is preferable in that a pressure-sensitive adhesive layer can be easily provided by applying a solution containing the polymer to the heat-resistant support layer and drying after polymerization. Solution polymerization is usually performed under a nitrogen atmosphere at a polymerization temperature and a polymerization time of 30 to 80 ° C. and 1 to 24 hours, respectively. The coating solution is prepared by diluting the polymer prepared as described above in an organic solvent. As the organic solvent, ethyl acetate, methyl ethyl ketone (MEK), toluene or a mixture thereof can be usually used. Next, the coating solution is uniformly applied to the heat-resistant support layer by die coating, knife coating, bar coating, or other known / common application methods. Since the coating solution consists essentially of the aforementioned polymer and solvent, uniform application can be easily realized. The coating solution is then dried with the heat resistant support layer to remove the solvent.

  Next, the obtained double-sided pressure-sensitive adhesive tape is bonded onto a carrier substrate, and the polymer is crosslinked by heating. For example, sufficient crosslinking can be performed by allowing the reaction to proceed at a temperature of 60 to 200 ° C. for about several tens of minutes to about 3 days.

In the case of producing a multilayer pressure-sensitive adhesive tape having no support layer, it can be produced by forming a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer on the peeled substrate and bonding them together. . Sufficient crosslinking can be carried out by laminating the second pressure-sensitive adhesive layer of the obtained multilayer pressure-sensitive adhesive tape on a carrier substrate and heating it under the above conditions.
Or sufficient bridge | crosslinking can also be performed by sticking a 2nd adhesive layer on a carrier base material, sticking a 1st adhesive layer continuously, and heating on said conditions.

  In the embodiment using the double-sided tape, a heat resistant support layer is selected that can withstand a temperature encountered in a process such as a solder reflow process (for example, 130 ° C. to 260 ° C.). The heat resistant support layer is a polyethylene terephthalate (PET) film, polyetherimide, polyethersulfone, polyethylene naphthalate or polyphenylene sulfide, polyetheretherketone, polyamideimide or polyimide film. In particular, in view of availability and chemical stability, PET, polyethylene naphthalate, polyphenylene sulfide, and polyimide are highly versatile and desirable. In consideration of handling and availability, the heat-resistant support layer preferably has a thickness of 1 to 250 μm.

  In addition, when the adhesiveness (throwing property) between the heat-resistant support layer and the pressure-sensitive adhesive layer of the double-sided tape is poor, when peeling the double-sided pressure-sensitive adhesive tape from the adherend, the space between the heat-resistant support layer and the pressure-sensitive adhesive layer May peel off. In such a case, the heat resistant support layer may be subjected to a surface treatment for easy adhesion by a well-known or conventional technique. A suitable example of such a surface treatment is a physical treatment method such as corona discharge treatment, flame treatment, plasma treatment or ultraviolet irradiation treatment, or a wet chemical treatment method. In particular, corona treatment is more preferable. The heat-resistant support layer subjected to the corona treatment is commercially available and can be easily obtained.

  Furthermore, as long as the purpose and effect of the present invention are not impaired, antioxidants, ultraviolet absorbers, fillers (for example, inorganic fillers, pigments, etc.), lubricants such as wax, tackifiers (for example, tackifier resins and other polymers, etc.) ), Additives such as a plasticizer, a curing accelerator, and a fluorescent pigment may be included in the pressure-sensitive adhesive layer.

The double-sided pressure-sensitive adhesive tape or multilayer pressure-sensitive adhesive tape of the present invention and a laminate comprising the same are used for temporarily fixing and conveying printed wiring boards. The double-sided pressure-sensitive adhesive tape or the multilayer pressure-sensitive adhesive tape of the present invention is particularly preferably used for a solder reflow process of a printed wiring board.
FIG. 1 shows a schematic view of a solder reflow process using the double-sided pressure-sensitive adhesive tape of the present invention.
First, the double-sided pressure-sensitive adhesive tape 10 having the support layer 2 having the uncrosslinked first pressure-sensitive adhesive layer 3 and the uncrosslinked second pressure-sensitive adhesive layer 4 on both surfaces is disposed on the carrier substrate 1 (step 1). Then, the double-sided pressure-sensitive adhesive tape 10 is cured by crosslinking the pressure-sensitive adhesive layer with heat on the carrier substrate 1 to form the holding and conveying jig 100 (step 2), and then printed on the first pressure-sensitive adhesive layer 3 The wiring board 5 is pasted (step 3). This is subjected to a reflow process (process 4). The reflow process is usually performed by passing it through a high temperature at a maximum temperature of about 260 ° C. for 1 to several minutes, for example, about 3 to 4 minutes. When the double-sided pressure-sensitive adhesive tape of the present invention is used, the adhesive force does not increase even after the reflow process, and is kept essentially constant. For this reason, the printed wiring board 5 can be peeled off from the double-sided pressure-sensitive adhesive tape 10 (step 5), returned to step 3, and the printed wiring board 5 can be bonded onto the first adhesive layer 3 of the double-sided pressure-sensitive adhesive tape. (Step 6). Thus, the reflow process can be performed 10 to several tens of times. Finally, the double-sided pressure-sensitive adhesive tape 10 can be peeled from the carrier substrate 1 (Step 7), and the carrier substrate can be used again in Step 1 (Step 8). Since the double-sided pressure-sensitive adhesive tape of the present invention has high cohesive strength and heat resistance, it can be peeled cleanly from the carrier substrate after use.

FIG. 2 shows a schematic view of a solder reflow process using a multilayer adhesive tape.
First, the multilayer adhesive tape 10 formed by laminating the uncrosslinked first pressure-sensitive adhesive layer 3 and the uncrosslinked second pressure-sensitive adhesive layer 4 is disposed on the carrier substrate 1 (step 1). This multilayer adhesive tape is manufactured by forming an uncrosslinked first adhesive layer on a release liner and forming an uncrosslinked second adhesive layer on another release liner and laminating them it can. Alternatively, Step 1 can also be performed by bonding an uncrosslinked second pressure-sensitive adhesive layer on the carrier substrate and further bonding an uncrosslinked first pressure-sensitive adhesive layer. The multilayer pressure-sensitive adhesive tape 10 is cured by crosslinking the pressure-sensitive adhesive layer on the carrier substrate 1 to form a holding and conveying jig 100 (step 2), and then printed wiring on the first pressure-sensitive adhesive layer 3 The plate 5 is pasted (Step 3). This is subjected to a reflow process (process 4). The reflow process is usually performed by passing it through a high temperature at a maximum temperature of about 260 ° C. for 1 to several minutes, for example, about 3 to 4 minutes. When the multilayer pressure-sensitive adhesive tape of the present invention is used, the adhesive force does not increase even after the reflow process, and is kept essentially constant. For this reason, the printed wiring board 5 can be peeled from the multilayer pressure-sensitive adhesive tape 10 (step 5), returned to step 3, and the printed wiring board 5 can be attached on the first adhesive layer 3 of the multilayer pressure-sensitive adhesive tape. (Step 6). Thus, the reflow process can be performed 10 to several tens of times. Finally, the multilayer adhesive tape 10 can be peeled from the carrier substrate 1 (step 7), and the carrier substrate can be used again in step 1 (step 8). Since the multilayer pressure-sensitive adhesive tape of the present invention has high cohesive strength and heat resistance, it can be peeled cleanly from the carrier substrate after use.

Below, based on an Example, this invention is demonstrated further in detail. The invention is not limited to the embodiments shown.
<Synthesis of acrylic copolymer>
First, an acrylic copolymer was produced. Table 2 shows the monomers used.

  A monomer mixture having a monomer composition ratio shown in Table 3 below was prepared in an ethyl acetate solvent at a monomer concentration of 40 wt%. To this solution, 2,2′azobis (2,4-dimethylvaleronitrile (V-65) as a polymerization initiator was added in an amount of 0.2 wt% with respect to the total mass of the monomers. After purging the solution with nitrogen, the temperature was raised to 55 ° C., and polymerization was carried out at that temperature for 24 hours to obtain an acrylic copolymer solution, glass transition temperature (Tg) of the copolymer before crosslinking. Was calculated by the formula of FOX as described above based on the homopolymer glass transition temperature of each monomer and the mass fraction of the monomer, for example, as Tg of PSA1, Tg = [1 / ((0.908 / 219 ) + (0.019 / 379) + (0.073 / 336))] = 226 (K) (−46 ° C.) The results are shown in Table 3.

Examples 1-4 and Comparative Examples 1-3
<Production of double-sided adhesive tape>
Toluene was added to the acrylic copolymer solution obtained as described above to adjust the solid content to about 20 wt%. Further, 2 wt% of an antioxidant (Ciba Japan Co., Ltd., Irganox 1330) was added to the acrylic copolymer. An adhesive layer is coated on a non-silicone release-treated polyethylene terephthalate (PET) film (3M JTP8800) with a thickness of 50 μm and dried in an oven at 65 ° C. for 3 minutes and then in an oven at 120 ° C. for 4 minutes. The laminate was laminated with a fluorine-based release-treated polyethylene terephthalate (PET) film (3593 # 5932) having a thickness of 50 μm to obtain a single-layer transfer tape. The thickness of the pressure-sensitive adhesive layer was 60 μm.

  Remove the fluorine-based release-treated polyethylene terephthalate (PET) film (3M # 5932) from the single-layer transfer tape obtained above and paste it on one side of a polyimide film (Toray DuPont, Kapton 100H) with a film thickness of 25 μm. In addition, a single-layer transfer tape made of the same or other pressure-sensitive adhesive layer was similarly bonded to the other surface of the polyimide film to obtain a double-sided pressure-sensitive adhesive tape. Table 4 shows combinations of pressure-sensitive adhesive layers of the produced double-sided tape.

<Preparation of holding conveyance jig having double-sided adhesive tape on carrier substrate>
The double-sided pressure-sensitive adhesive tape obtained above was slit to a width of 15 mm, and one side of the pressure-sensitive adhesive layer (second pressure-sensitive adhesive layer) was pressure-bonded to the aluminum plate (1.5 mm thickness, surface alumite treatment) once with a 2 kg roller, A simple holding and conveying jig was used. The crimped aluminum plate with a double-sided tape was placed in an oven at 190 ° C. for 30 minutes, and the tape was subjected to heat crosslinking treatment.

Example 5 and Comparative Example 4
<Production of multilayer adhesive tape>
Toluene was added to the acrylic copolymer solution obtained as described above to adjust the solid content to about 20 wt%. Further, 2 wt% of an antioxidant (Ciba Japan Co., Ltd., Irganox 1330) was added to the acrylic copolymer. An adhesive layer is coated on a 50 μm-thick non-silicone release-treated polyethylene terephthalate (PET) film (3M JTP8800 or JTP8790) and placed in an oven at 65 ° C. for 3 minutes and then in an oven at 120 ° C. for 4 minutes. It was dried and laminated with a fluorine-based release-treated polyethylene terephthalate (PET) film (# 5932 manufactured by 3M) to obtain a single-layer transfer tape. The thickness of the pressure-sensitive adhesive layer was 60 μm. Prepare a combination of single-layer transfer tapes made of different adhesives formed on two different types of non-silicone release polyethylene terephthalate (PET) films (3M JTP8800, JTP8790). Fluorine-based release of each single-layer transfer tape The treated polyethylene terephthalate (PET) film (3M # 5932) was peeled off and the adhesive layer surfaces were bonded together to obtain a multilayer adhesive tape.

<Preparation 1 of a holding conveyance jig which has a multilayer adhesive tape on a carrier substrate>
The multilayer adhesive tape obtained above is slit to a width of 15 mm, the non-silicone release-treated polyethylene terephthalate (PET) film (3M JTP8800) is peeled off, and the exposed adhesive layer (second adhesive layer) is aluminum. The plate (1.5 mm thickness, surface alumite treatment) was reciprocated once with a 2 kg roller, and the non-silicone release-treated polyethylene terephthalate (PET) film (3M JTP8790) was peeled off to obtain a simple holding and conveying jig. The crimped aluminum plate with the multilayer adhesive tape was placed in an oven at 180 ° C. for 50 minutes, and the tape was subjected to heat crosslinking treatment.

Example 6 and Comparative Example 5
<Preparation 2 of the holding conveyance jig which has a multilayer adhesive tape on a carrier substrate>
The single-layer transfer tape obtained above was slit to a width of 15 mm, the fluorine-based release-treated polyethylene terephthalate (PET) film (3M # 5932) was peeled off, and the adhesive layer (second adhesive layer) was made of an aluminum plate. A non-silicone release-treated polyethylene terephthalate (PET) film (manufactured by 3M, JTP8790) was peeled off after being reciprocated once with a 2 kg roller (1.5 mm thickness, surface alumite treatment). A single-layer transfer tape composed of another pressure-sensitive adhesive layer was similarly bonded onto the second pressure-sensitive adhesive layer to obtain a simple holding and conveying jig. The crimped aluminum plate with the multilayer adhesive tape was placed in an oven at 180 ° C. for 50 minutes, and the tape was subjected to heat crosslinking treatment.

<Peelability evaluation of polyimide film before and after reflow>
20 mm as an adherend equivalent to a printed wiring board on the exposed adhesive layer (first adhesive layer) of the double-sided adhesive tape or the aluminum plate with multilayer adhesive tape (holding and conveying jig) obtained above. A polyimide film having a width (Upilex 25S) was pressure-bonded once by a 2 kg roller. The sample was allowed to stand at 25 ° C. for 20 minutes, and the 180 ° peel adhesive strength (N / 10 mm) from the polyimide film was measured in a 25 ° C. atmosphere at a peeling rate of 300 mm / min. This was the initial adhesive force, and the state of the peeled polyimide film was observed with the naked eye. When there is no defect such as curling or bending, “good” is indicated, and when there is a defect, the content of the defect is described. Table 4 shows the results of the peelability of the polyimide film.

  After measuring the initial adhesive force, another polyimide film having a width of 20 mm was subjected to one reciprocal pressure bonding with a 2 kg roller to the first pressure-sensitive adhesive layer exposed on the tape. This sample was passed through a reflow oven (Baby Reflow, manufactured by Asahi Electronics Co., Ltd.) set at preheating 150 ° C. to 200 ° C. for 60 to 70 seconds, main heating 230 ° C. or more for 30 to 40 seconds, and peak temperature 260 ° C., and returned to room temperature. After that, the adhesive strength was measured using the above method. The same operation was repeated while changing the polyimide film having a width of 20 mm every time the sample was passed through the reflow oven, and the adhesive strength after 10 reflow treatments was measured. In the initial adhesive strength evaluation, “floating”, “peeling” and “curl” samples were not included in the evaluation after the reflow treatment.

<Heat resistance evaluation>
After repeating the above reflow treatment 10 times, the state of the adhesive tape on the holding and conveying jig was observed with the naked eye. A case where there was no heat damage such as heat shrinkage or burning was judged as “good”. The results are shown in Table 4.

<Evaluation of peelability of double-sided adhesive tape after reflow from aluminum plate>
After repeating the above reflow treatment 10 times, each double-sided adhesive tape was peeled from the aluminum plate at a 90 ° angle in a 25 ° C atmosphere at a peeling speed of 300 mm / min, and the 90 ° peel adhesive strength (N / 10 mm) was measured. did. The state of the aluminum plate after peeling was observed with the naked eye. A case where there was no defect such as adhesive residue was judged as “good”.

<Evaluation of peelability of multilayer adhesive tape after reflow from aluminum plate>
After repeating the above reflow treatment 10 times, a single-sided tape (3M # 898) slit to a width of 15 mm on the multilayer adhesive tape was sufficiently pressed one or more times using a 2 kg roller. The multi-layer adhesive tape was peeled from the aluminum plate by peeling the pressure-bonded single-sided tape. The state of the aluminum plate after peeling was observed with the naked eye. A case where there was no defect such as adhesive residue was judged as “good”.

  In Examples 1 to 6, the first pressure-sensitive adhesive layer was stable without increasing the adhesive force by repeating the reflow treatment 10 times. For this reason, repeated temporary fixing of the polyimide film is possible. Thermal damage such as shrinkage or burning is not observed on the double-sided tape after 10 reflow treatments, and it has excellent heat resistance. Moreover, the adhesive force with respect to the aluminum plate was enough for the 2nd adhesive layer, and the peeling of the adhesive tape from an aluminum plate did not arise in the case of peeling of a polyimide film. On the other hand, after use, it could be peeled off from the aluminum plate without any adhesive residue.

In Comparative Example 1, the adhesive force of the second pressure-sensitive adhesive layer to the aluminum plate is not sufficient, and when the polyimide film is peeled from the double-sided tape, there is a portion where the end of the tape is slightly bent and floats from the aluminum plate. Was observed.
Moreover, in Comparative Example 2, Comparative Example 4, and Comparative Example 5, the tape was completely peeled from the aluminum plate when the polyimide was peeled before reflow, and evaluation after the reflow treatment could not be performed.
Furthermore, in Comparative Example 3, the polyimide film could be peeled from the double-sided tape, but damage (remarkable curl) was observed on the peeled film.

  The pressure-sensitive adhesive tape of the present invention can be favorably used as a temporary fixing tape in the production of printed wiring boards and the like and surface mounting processes. There is no mixing of low molecular weight siloxane, and it has excellent balance between adhesion to printed wiring board and adhesion to carrier substrate, and peelability of adhesive tape from printed wiring board and carrier substrate, and can be used repeatedly. It is.

The schematic of the solder reflow process using the double-sided adhesive tape of this invention is shown. The schematic of the solder reflow process using the multilayer adhesive tape of this invention is shown.

DESCRIPTION OF SYMBOLS 1 Carrier base material 2 Support layer 3 1st adhesive layer 4 2nd adhesive layer 5 Printed wiring board 10 Double-sided adhesive tape, multilayer adhesive tape 100 Holding conveyance jig

Claims (7)

A carrier substrate for a printed wiring board, and a method for producing a laminate including an adhesive tape for temporarily fixing the printed wiring board to the carrier substrate,
A first pressure-sensitive adhesive layer containing a copolymer of monomers including the following (a) to (c), having a glass transition temperature (Tg) before crosslinking of −65 ° C. or higher and lower than −30 ° C. is formed. thing,
Forming a second pressure-sensitive adhesive layer containing a copolymer of monomers containing the following (a) to (c) having a glass transition temperature (Tg) before crosslinking of -30 ° C or higher and 0 ° C or lower;
Forming an adhesive tape comprising the first adhesive layer and the second adhesive layer as outermost layers,
Bonding the second pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape to a carrier substrate, placing the first pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape as an uppermost layer, and
Cross-linking the second pressure-sensitive adhesive layer and the first pressure-sensitive adhesive layer on the carrier substrate, and the pressure-sensitive adhesive tape is a multilayer pressure-sensitive adhesive tape or a double-sided pressure-sensitive adhesive tape,
(A) alkyl (meth) acrylate having 1 to 12 carbon atoms in the alkyl group: 90 to 99 parts by mass,
(B) (meth) acrylic acid: 1 to 10 parts by mass,
(C) Glycidyl (meth) acrylate: 0.5 to 2.5 moles relative to 1.0 mole of (meth) acrylic acid (b),
The manufacturing method of the laminated body which is.   The pressure-sensitive adhesive tape is a double-sided pressure-sensitive adhesive tape, the first pressure-sensitive adhesive layer is formed on one surface of the heat-resistant support layer, the second pressure-sensitive adhesive layer is formed on the opposite surface, and then the second pressure-sensitive adhesive layer is formed. The manufacturing method of the laminated body containing the adhesive tape of Claim 1 which affixes the adhesive layer of this to the said carrier base material.   The pressure-sensitive adhesive tape is a multilayer pressure-sensitive adhesive tape, the first pressure-sensitive adhesive layer is formed on a release liner, the second pressure-sensitive adhesive layer is formed on another release liner, and the first pressure-sensitive adhesive layer and A laminate comprising the pressure-sensitive adhesive tape according to claim 1, wherein a multilayer pressure-sensitive adhesive layer is formed by laminating the second pressure-sensitive adhesive layer, and then the second pressure-sensitive adhesive layer is bonded to the carrier substrate. Method. A carrier substrate for a printed wiring board, and a method for producing a laminate including an adhesive tape for temporarily fixing the printed wiring board to the carrier substrate,
A second pressure-sensitive adhesive layer containing a copolymer of monomers containing the following (a) to (c) having a glass transition temperature (Tg) before cross-linking of not lower than −30 ° C. and not higher than 0 ° C. on the carrier substrate: Pasted on, then
The first pressure-sensitive adhesive layer containing a copolymer of monomers containing the following (a) to (c), having a glass transition temperature (Tg) before crosslinking of −65 ° C. or higher and lower than −30 ° C. Affixing on the adhesive layer, and
Cross-linking the second pressure-sensitive adhesive layer and the first pressure-sensitive adhesive layer on the carrier substrate,
(A) alkyl (meth) acrylate having 1 to 12 carbon atoms in the alkyl group: 90 to 99 parts by mass,
(B) (meth) acrylic acid: 1 to 10 parts by mass,
(C) Glycidyl (meth) acrylate: 0.5 to 2.5 moles relative to 1.0 mole of (meth) acrylic acid (b),
The manufacturing method of the laminated body which is. A first pressure-sensitive adhesive layer containing a copolymer of monomers containing the following (a) to (c), wherein the glass transition temperature (Tg) before crosslinking is −65 ° C. or higher and lower than −30 ° C .;
A second pressure-sensitive adhesive layer containing a copolymer of monomers containing the following (a) to (c), wherein the glass transition temperature (Tg) before crosslinking is -30 ° C or higher and 0 ° C or lower;
Each of which is an adhesive tape for temporarily fixing a printed wiring board to a carrier substrate,
(A) alkyl (meth) acrylate having 1 to 12 carbon atoms in the alkyl group: 90 to 99 parts by mass,
(B) (meth) acrylic acid: 1 to 10 parts by mass,
(C) Glycidyl (meth) acrylate: A crosslinkable pressure-sensitive adhesive tape that is 0.5 to 2.5 moles per 1.0 mole of (meth) acrylic acid (b).   The said adhesive tape is a double-sided adhesive tape, The said 1st adhesive layer is included on the single side | surface of a heat resistant support layer, The bridge | crosslinking of Claim 5 including the said 2nd adhesive layer on the opposite surface. Possible adhesive tape.   The crosslinkable pressure-sensitive adhesive tape according to claim 5, wherein the pressure-sensitive adhesive tape is a multilayer pressure-sensitive adhesive tape, and is a multilayer pressure-sensitive adhesive tape in which the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer are laminated.

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