JP7207599B1 - insulating adhesive tape - Google Patents

Abstract

The present invention provides an insulating pressure-sensitive adhesive tape that has heat resistance, good tracking resistance that does not cause a reverse trend phenomenon, high insulating properties, and good winding workability. An insulating adhesive tape having an insulating layer, an adhesive layer, and a glass cloth layer, wherein the glass cloth layer is positioned between the insulating layer and the adhesive layer, and the glass cloth layer is: The solution is an insulating adhesive tape impregnated with at least one of said insulating layer or said adhesive layer. [Selection drawing] Fig. 1

Description

The present disclosure particularly relates to an insulating pressure-sensitive adhesive tape that has heat resistance, good tracking resistance that does not cause a reverse trend phenomenon, high insulation properties, and excellent winding workability.

In recent years, EVs (electric vehicles) and HEVs (hybrid electric vehicles) that run motors with battery electricity, and FCVs (which run motors with electricity obtained from the chemical reaction of hydrogen and oxygen) have become popular around the world. fuel cell vehicles) are rapidly becoming popular. The current mainstream battery voltage for driving motors is 400V, but it is expected to be boosted to 800V and even 1000V in order to make cables thinner and shorten the charging time, and has heat resistance and high tracking resistance. A need exists for an insulating adhesive tape. In addition, due to the trend toward lighter weight and higher density, the size of parts is becoming smaller, and the curved surface (R) of the part where the tape is wound is becoming smaller. hereinafter abbreviated as winding workability). In addition, although the CTI is certified as 600 volts, there is a problem of a reverse trend phenomenon that causes a tracking phenomenon in a low voltage band around 300 volts.

JP 2010-76261 A

In the insulating pressure-sensitive adhesive tape disclosed in Prior Document 1, the reverse trend phenomenon occurs and the heat resistance is greatly insufficient. Also, in a dielectric breakdown voltage test, insulation was insufficient, such as dielectric breakdown at a low voltage.

The present disclosure has been made in view of such points, and the purpose thereof is to provide heat resistance, good tracking resistance that does not cause reverse trend phenomenon, high insulation, and winding workability. To provide an insulating pressure-sensitive adhesive tape excellent in

In order to achieve the above object, an insulating adhesive tape composed of a laminate of three or more layers having at least an insulating layer and an adhesive layer and a glass cloth layer therebetween, comprising: A laminated structure was adopted. Specifically, it is as follows.

That is, the present invention provides an insulating adhesive tape having an insulating layer, an adhesive layer, and a glass cloth layer, wherein the glass cloth layer is positioned between the insulating layer and the adhesive layer, and the glass cloth layer relates to an insulating adhesive tape, characterized in that at least one of said insulating layer or said adhesive layer is impregnated.

According to the present disclosure, there is provided an insulating adhesive tape that has excellent tracking resistance, good winding processability even for miniaturized high-voltage parts, and furthermore, has both high insulation and heat resistance. be able to.

1 is a schematic side view showing a cross section of an insulating adhesive tape according to a first embodiment of the present disclosure; FIG. It is a schematic side view which shows one example of the insulating adhesive tape cross section in a working range. FIG. 4A is a schematic side view showing cross sections at different positions of the insulating adhesive tape according to the first embodiment of the present disclosure; FIG. 5 is a schematic side view showing a cross section of an insulating adhesive tape according to a second embodiment of the present disclosure; FIG. 5 is a schematic side view showing a cross section of an insulating adhesive tape according to a third embodiment of the present disclosure; FIG. 11 is a schematic side view showing a cross section of an insulating adhesive tape according to a fourth embodiment of the present disclosure; FIG. 11 is a schematic side view showing a cross section of an insulating adhesive tape according to a fifth embodiment of the present disclosure;

Hereinafter, this embodiment will be described in detail based on the drawings. The following description of preferred embodiments is merely exemplary in nature and is not intended to limit the invention, its applications or uses. In the present invention, the terms insulating adhesive tape, adhesive sheet, adhesive tape, and adhesive film are synonymous.

[Insulating adhesive tape]
An insulating adhesive tape according to Embodiment 1 will be described with reference to FIG. FIG. 1(1) is a plan view of the insulating adhesive tape 1, showing the glass cloth layer for the sake of convenience. FIG. 1(2) is a cross-sectional view of the tape taken along line DD' of FIG. 1(1). As shown in FIG. 1(2), the insulating adhesive tape 1 has an insulating layer 12, a glass cloth layer 11 and an adhesive layer 13, and the glass cloth layer is positioned between the insulating layer and the adhesive layer (hereinafter referred to as Also abbreviated as tape). The insulating layer 12 and the adhesive layer 13 impregnate the glass cloth layer 11 and are in contact with each other in the glass cloth layer. At least one of the insulating layer 12 and the adhesive layer 13 may be impregnated into the glass cloth layer 11, but it is preferable to impregnate both the insulating layer 12 and the adhesive layer 13 from the viewpoint of improving heat resistance. . Each impregnated portion of the insulating layer 12 and the adhesive layer 13 in the insulating adhesive tape 1 will be described in detail. A dotted line L1 in FIG. 1B is the outermost layer boundary line of the insulating layer 12 . L3 is the interface between the insulating layer and the adhesive layer. L5 is the outermost layer boundary line of the adhesive layer 13 . Here, the distance between L1 and L3 is defined as the thickness of the insulating layer 12, the distance between L3 and L5 as the thickness of the adhesive layer, and the distance between L1 and L5 as the thickness of the tape. L2 and L4 respectively indicate the apexes of the upper and lower convex portions when the glass cloth layer is observed from the cross section, and the distance between L2 and L4 is defined as the thickness of the glass cloth layer in the present application.
Further, L1 to L2 in which the glass cloth layer is not impregnated with the insulating layer 12 are defined as an insulating non-impregnated layer 12a, and L2 to L3 in which the insulating layer 12 is impregnated are defined as an insulating impregnated layer 12b. Similarly, L4 to L5 in which the adhesive layer 13 is not impregnated in the glass cloth layer are defined as the adhesive non-impregnated layer 13a, and L3 to L4 in which the adhesive layer 13 is impregnated are defined as the adhesive impregnated layer 13b.

FIG. 2 is a schematic cross-sectional view of the tape for explaining a configuration in which a part of the glass cloth layer has voids. In this case, as shown in FIG. 2, the insulation impregnation layer is formed between the insulation layer interfaces L3-1 and L2 on the glass cloth layer impregnation side. Similarly, the adhesive layer-impregnated layer is formed between the adhesive layer interfaces L3-2 and L4 on the glass cloth layer impregnated side.
Although a part of the glass cloth layer may have voids, the insulating layer 12 and the adhesive layer 13 are completely impregnated with the glass cloth layer 11 as shown in FIG. preferable.

The thickness of the insulating adhesive tape is preferably 30-200 μm, more preferably 45-100 μm. When the thickness is 30 μm or more, the heat resistance and insulation properties are improved, and when the thickness is 200 μm or less, the winding workability is improved.

The thickness of the glass cloth layer 11 is preferably 10 μm to 50 μm, more preferably 20 μm to 35 μm. Within the preferred range, the insulating pressure-sensitive adhesive tape has sufficient flexibility while maintaining sufficient strength, and improves heat resistance and winding workability.
The thickness of the insulating layer 12 is preferably 1 μm to 100 μm, more preferably 20 μm to 60 μm. The thickness of the insulating non-impregnation layer 12a is preferably 1-30 μm, more preferably 5-15 μm. When the thicknesses of the insulating layer 12 and the insulating non-impregnated layer 12a are within the above preferred range, the tracking resistance and winding workability of the tape are improved in a well-balanced manner. The ratio of the thickness of the insulating impregnated layer 12b to the thickness of the glass cloth layer is preferably 50% or more, more preferably 70% or more. When the thickness is in the preferable range, the gaps in the glass cloth layer 11 are filled with the insulating layer, so that the insulating properties and the heat resistance are greatly improved.

The thickness of the adhesive layer 13 is preferably 5 μm to 100 μm, more preferably 20 μm to 40 μm. The thickness of the adhesive non-impregnated layer 13a is preferably 5 μm to 50 μm, more preferably 20 μm to 35 μm. When the thicknesses of the adhesive layer 13 and the adhesive non-impregnated layer 13a are within the above preferable range, sufficient adhesive performance can be obtained for unevenness of various adherends.

The ratio of the thickness of the adhesive impregnated layer 13b to the thickness of the glass cloth layer is preferably 1 to less than 50%, more preferably 1 to less than 30%. When the content is in the above range, the gaps in the glass cloth layer 11 are filled with the insulating layer, and the insulating properties of the tape are improved.
As described above, the glass cloth layer 11 preferably has no voids and is filled with the insulating impregnated layer 12b or the adhesive impregnated layer 13b. A thickness of 11 is preferable from the viewpoint of improving insulation.

The thickness of each layer of the insulating adhesive tape is evaluated by scanning electron microscope observation (SEM observation) of the cross section of the tape, and is the average value obtained by measuring 10 arbitrary points in observation images at a magnification of 300 to 1000 times. The cross-section to be measured is obtained by obtaining a cross-section where the warp and the weft intersect and folds as shown in FIG. 3(1) EE'. This is because it is easy to measure the thicknesses of the insulating layer 12 and the adhesive layer 13 because the portions where the warp and the weft shown in FIG. 3(2) do not exist can be confirmed. As shown in FIG. 3(2), the thickness of the insulating adhesive tape 1 is measured from the outermost surface of the insulating non-impregnated layer 12a and the adhesive non-impregnated layer 13a. The thickness of the insulating non-impregnated layer 12a and the adhesive non-impregnated layer 13a is measured so that the thicknesses of the non-impregnated insulating layer 12a and the adhesive non-impregnated layer 13a are the smallest among the positions that can be confirmed. In other words, the thickness of the non-impregnated insulating layer 12a and the non-impregnated adhesive layer 13a is obtained by subtracting the thickness of the entire tape from the thickness of the glass cloth layer 11 including the irregularities.

As a method for obtaining a cross section of the insulating adhesive tape 1, the target sample frozen with liquid nitrogen or the like is split (freeze fracture method), the target sample is cut with a sharp blade such as a razor (microtome method), or cut out with a cutter or the like. In addition, there is a method (ion milling method) in which the cross section of the target sample is smoothed with abrasive paper, and the sample is processed by irradiating the sample with an ion beam using a cross section polisher (ion milling method).A smooth cross section can be obtained by various methods. However, among these, the ion milling method is preferable.
In addition, when it is difficult to judge by color and shape, the cross section is scanned with a scanning probe microscope (sometimes referred to as SPM) because the difference in elastic modulus between the glass cloth layer 11, the insulating layer 12, and the adhesive layer 13 is large. It is also possible to discriminate each layer from an image that expresses the magnitude of the elastic modulus as an image.
Furthermore, when the interface between the insulating impregnated layer 12b and the adhesive impregnated layer 13b in the glass cloth layer 11 cannot be sufficiently distinguished, the ethyl acetate is stirred while the adhesive tape is immersed in a container filled with ethyl acetate at 80° C. for 12 hours. After eluting and removing only the adhesive layer by moving it with a particle or the like, the layer remaining on the glass cloth layer can be determined as the insulating impregnated layer 12b by cross-sectional observation, and can be determined in combination with the thickness measurement before immersion.

The 180° C. peeling adhesive strength of the adhesive layer of the insulating adhesive tape to the stainless steel plate is preferably 0.1 to 100 kgf/20 mm. Practically, it is more preferably 1 to 50 kgf/25 mm, more preferably 5 to 30 kgf/25 mm, considering suppression of unintended peeling and a method of winding around a tubular core material and pulling out only the required amount. Adhesive strength measurement of the product of the present invention refers to a value measured using a “cold-rolled stainless steel plate” described in JIS G 4305:2012 in accordance with JIS Z0237:2009.

[Glass cloth layer]
As shown in FIG. 1, the glass cloth layer 11 is a layer positioned between the insulating layer and the adhesive layer to support the insulating adhesive tape. The glass cloth layer 11 has a layer in which at least one of the insulating layer 12 and the adhesive layer 13 is partially impregnated, that is, it has at least an insulating impregnated layer 12b or an adhesive impregnated layer 12b as shown in FIG. 1(2). The glass cloth is made by weaving glass threads, and the glass threads are further made by bundling small-diameter glass filaments with an adhesive (also called yarn). By including such a glass cloth layer 11, the heat resistance and winding workability are greatly improved.

The glass thread preferably has a diameter of 100 to 500 μm, more preferably 125 to 400 μm, even more preferably 150 to 250 μm. Heat resistance and winding workability are improved by setting the content within the above range. The diameter of the glass yarn is the average value of 20 warp yarns and 20 weft yarns when observed with a microscope at a magnification of 50 to 100 perpendicularly to the surface of the glass cloth layer 11 or the insulating adhesive tape. The cross-section of the glass thread is not a perfect circle, but most of them are extremely elliptical, and the diameter of the observed glass thread corresponds to the longest diameter of the ellipse. That is, C in FIG. 1 corresponds to the diameter of the glass thread. If visual recognition is difficult, the average value of the longest diameters of 20 arbitrarily selected tapes by cross-sectional observation of the tape is used. By setting the thickness within the preferable range, the flexibility and the strength required for the insulating adhesive tape can be sufficiently satisfied.

The glass yarn is preferably formed by bundling 10 to 500 glass filaments, more preferably 30 to 120, more preferably 40 to 80. The glass filament diameter is 1 to 10 μm, more preferably 3.5 to 5.5 μm. The smaller the diameter of the glass filament or the smaller the number of filaments to be bundled, the lower the strength of the glass yarn, but the higher the flexibility. can satisfy A tape with low flexibility tends to cause a problem that the end of the tape tends to come off during the winding process.

Since glass cloth is a woven fabric, its weaving method is not limited, but is selected from plain weave, twill weave, and satin weave, and plain weave is preferred from the viewpoint of productivity and uniformity. The weave density is the average value of the number of warp or weft yarns in any three 10 mm length ranges observed with a microscope at 100 to 500 times the surface of the glass cloth. 50 lines/10 mm, more preferably 15 to 40 lines/10 mm, and even more preferably 20 to 35 lines/10 mm. The 10 mm length of the observation range is set so as to be perpendicular to the observed direction of the glass thread. The weave density of the glass cloth layer of the insulating adhesive tape can be confirmed by microscopic observation of the surface of the tape when the insulating layer or the adhesive layer is transparent. If it cannot be confirmed, it can be confirmed by dissolving and removing the adhesive layer with an organic solvent. As the number of glass threads increases, the strength of the glass cloth layer increases, but the impregnability of the insulating layer and adhesive layer decreases, and voids tend to occur due to insufficient impregnation. worsens. If the number of glass threads is small, the impregnation of the insulating layer and the adhesive layer into the glass cloth increases and the voids decrease and the insulation increases, but the tensile strength decreases, which causes problems such as the tape breaking during processing. easier. By being in the preferable range, it is possible to provide a rim pressure-sensitive adhesive tape with high insulating properties and excellent winding workability.
When non-woven glass cloth or glass fiber filler is used between the insulating layer and the adhesive layer instead of glass cloth, it is difficult to impregnate with resin and the insulating property is greatly inferior in the case of non-woven glass cloth. cannot be used due to its poor heat resistance.

The composition of the glass used for the glass cloth is not particularly limited. , densities can be changed and performance can be imparted to the present invention. For example, when the ratio of silicon oxide to aluminum oxide is increased, the tensile strength at break is improved, and when the ratio of boron oxide is increased, the density and dielectric constant are decreased.

The glass filament diameter and the number of bundles can be confirmed by various methods and are not particularly limited. As a method to obtain a cross section, a target sample frozen with liquid nitrogen or the like is split (freeze fracture method), a target sample is cut with a sharp blade such as a razor (microtome method), or a cross section of the target sample is cut out with a cutter, etc. There is a method (ion milling method) in which the sample is processed by irradiating the sample with an ion beam using a cross-section polisher device, and a smooth cross section can be obtained by various methods. Ion milling methods are preferred.
The diameter is measured by averaging the long and short sides of cross sections of 10 arbitrary warp and weft glass filaments. In addition, the number of warps and wefts is determined from three arbitrary points of 10 mm square, and if it is not visible, after impregnating the tape with an organic solvent, remove the dissolved adhesive layer, and remove the exposed surface of the glass cloth layer. It can also be confirmed from microscopic observation. Further, if the glass cloth layer is sufficiently visible from the tape surface, the immersion in the organic solvent is unnecessary.
In addition, if it is difficult to judge by color or shape, the difference in elastic modulus between glass and resin is large. It can also be confirmed by the expressed image.

A commercially available product or the like can be used as the glass cloth. For example, E-1037 (thickness: 27 μm) manufactured by Nitto Boseki Co., Ltd. can be used. Alternatively, one obtained by production by a conventionally known method may be used.

[Insulating layer]
The insulating layer is a cured product of an insulating composition.
The insulating layer 12 is located above the adhesive layer 13 of the insulating adhesive tape 1 in FIG. When the adhesive layer 13 is completely impregnated with the glass cloth layer, the insulating impregnated layer 12b may not exist.
The insulating layer 12 provides the insulating adhesive tape with tracking resistance, insulating properties and flexibility, that is, winding workability. The mechanism by which tracking occurs is that when voltage is applied to the insulation layer, which is an insulator, with contamination, dust, etc., and moisture, current flows through the insulation layer, and when the moisture evaporates and dries due to Joule heat, the current flows. is concentrated in one part to generate minute discharge, and part of the insulating layer is decomposed and carbonized.

Therefore, as a material for forming the insulating layer 12, (1) the amount of carbon contained is small (it is difficult to form a carbonized conductive path), (2) the insulation is high, (3) the heat resistance is high, and (4) the material is flexible. It is ideal that the insulating composition, which is a precursor thereof, has the four properties of high toughness. Ideally, the glass cloth layer 11 should be easily impregnated and should not form voids in the glass cloth layer 11 . In particular, for the reason (1), the tracking phenomenon cannot be solved simply by improving insulation.

Materials having the above properties (1) to (4) include, for example, a cured product by active energy rays, a polyimide having an aromatic ring concentration of 30% by mass or less, and a polyamide having an aromatic ring concentration of 30% by mass or less. A resin as the main component is preferred. A cured product by active energy rays is more preferable from the viewpoint of further improving winding workability.

<Curified product by active energy ray>
A product cured by an active energy ray contains a polymerizable compound, and when irradiated with an active energy ray such as an ultraviolet ray or an electron beam, the compound is polymerized and cured. In general, an ethylenic double bond ( alkenyl group). There are many ready-made products, and acrylic materials mainly composed of acrylic acid ester skeletons or methacrylic acid ester skeletons are preferable because they are relatively inexpensive. Urethane acrylate oligomers (simply referred to as oligomer There is also.) is preferable.

The insulating composition for forming the insulating layer 12 is mainly composed of a component that can be cured by an active energy ray. It is preferable to add an agent and a solvent and use it as a coating liquid.

Active energy rays can be electromagnetic waves or charged particle rays that have energy quanta, and specifically, ultraviolet rays, electron beams, and the like can be used. In particular, ultraviolet light is preferred because it is easy to handle. Irradiation with ultraviolet rays can be performed using a high-pressure mercury lamp, a xenon lamp, or the like. The irradiation intensity of ultraviolet rays is preferably about 50 to 1000 mW/cm2. Further, the integrated amount of UV light is preferably 50 to 10000 mJ/cm2, more preferably 80 to 5000 mJ/cm2, and even more preferably 200 to 2000 mJ/cm2. On the other hand, electron beam irradiation can be performed using an electron beam accelerator or the like. The electron beam irradiation dose is preferably about 10 to 1000 krad.

A urethane acrylate oligomer is a reaction product of at least a polyvalent isocyanate and a (meth)acrylate having an active hydrogen group, and is characterized by having a plurality of alkenyl groups at the end of the molecule. Expansion with polyol compounds, acids, and amine compounds is also common. A urethane acrylate oligomer having a plurality of alkenyl groups in the molecule is rapidly cured by activation energy such as ultraviolet rays and electron beams due to unsaturated carbon bonds derived from acrylate. The resulting cured product is rigid and has excellent chemical resistance. When the radically polymerizable cross-linking component is cross-linked by ultraviolet light or the like, a photopolymerization initiator can be used, and a polymerization accelerator can also be used in combination. In the case of cross-linking with an electron beam, these may not be blended.

The weight average molecular weight (Mw) of the urethane acrylate oligomer is preferably from 300 to 15,000, more preferably from 500 to 5,000, even more preferably from 700 to 2,500. When it is 15000 or less, it is excellent in impregnation to the glass cloth when drying (uncured and solvent-free state) after coating on the glass cloth and excellent bubble removal during drying, and voids inside the glass cloth. can be suppressed and the insulation improves. When it is 300 or more, shrinkage during curing can be suppressed, and the resulting cured product is less likely to become brittle and can ensure flexibility, thereby improving winding workability.

The number of functional groups of the urethane acrylate oligomer is preferably 2-5, more preferably 3-4. For example, when 100 parts of a pentafunctional urethane acrylate oligomer is mixed with 100 parts of a trifunctional urethane acrylate oligomer, it can be regarded as being substantially tetrafunctional. When it is in the preferable range, it is possible to suppress twisting and voids due to cure shrinkage of the insulating layer, and the insulating property is enhanced due to the high crosslinking density while maintaining the flexibility. Further, when it is in the preferable range, the balance of flexibility, strength, and insulation is excellent.

The urethane acrylate oligomer has a polyoxyalkylene chain (EO chain: ethylene oxide chain, PO chain: propylene oxide chain, ethylene glycol chain, propylene glycol chain) from the viewpoint of shrinkage suppression and flexibility after curing. It is preferable to have The polyoxyalkylene chain can be easily identified by infrared absorption spectrum (IR spectrum), and even if it contains a polyoxyalkylene chain-containing additive as an additive, it is immersed in a MEK (methyl ethyl ketone) solution at 25 ° C. for 3 days. If the infrared absorption spectrum after curing is sufficiently distinguishable, it can be determined that the cured urethane acrylate oligomer is incorporated in the structure of the urethane acrylate oligomer, that is, has a polyoxyalkylene chain. When the infrared absorption spectrum shifts due to steric hindrance, NMR spectrum and gas chromatography may be used in combination. When gas chromatography is used, the presence or absence of EO chains and PO chains can be determined using a calibration curve of the column passage times.

Monofunctional hydroxy-containing acrylates such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxy-3-chloropropyl acrylate, N-(2-hydroxyethyl) acrylamide, 2-hydroxy-3-phenoxypropyl acrylate, 2 -Hydroxy-3-allyloxypropyl acrylate, 2-hydroxy-3-allyloxypropyl acrylate, 2-acryloyloxyethyl-2-hydroxypropyl phthalate can be used.

Monofunctional hydroxy-containing methacrylates include 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxy-3-chloropropyl methacrylate, 2-hydroxy-3-phenoxypropyl methacrylate, 2-hydroxy-3-allyloxypropyl methacrylate, 2 -methacryloyloxyethyl-2-hydroxypropyl phthalate can be used.

Bifunctional acrylates such as 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol 200 diacrylate, Polyethylene glycol 300 diacrylate, polyethylene glycol 400 diacrylate, polyethylene glycol 600 diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, tetrapropylene glycol diacrylate, polypropylene glycol 400 diacrylate, polypropylene glycol 700 diacrylate, neopentyl Glycol diacrylate, neopentyl glycol PO-modified diacrylate, neopentyl glycol hydroxypivalate diacrylate, caprolactone adduct diacrylate of neopentyl glycol hydroxypivalate, 1,6-hexanediol bis(2-hydroxy-3- acryloyloxypropyl) ether, bis(4-acryloxypolyethoxyphenyl)propane, 1,9-nonanediol diacrylate, pentaerythritol diacrylate, pentaerythritol diacrylate monostearate, pentaerythritol diacrylate monobenzoate, bisphenol A di Acrylate, EO-modified bisphenol A diacrylate, PO-modified bisphenol A diacrylate, hydrogenated bisphenol A diacrylate, EO-modified hydrogenated bisphenol A diacrylate, PO-modified hydrogenated bisphenol A diacrylate, bisphenol F diacrylate, EO-modified bisphenol F Diacrylate, PO-modified bisphenol F diacrylate, EO-modified tetrabromobisphenol A diacrylate, tricyclodecanedimethylol diacrylate, isocyanuric acid EO-modified diacrylate, ethoxylated isocyanuric acid diacrylate, 2-hydroxy-1,3-dia Cryloxypropane, pentaerythritol diacrylate can be used.

Trifunctional acrylates such as glycerin PO-modified triacrylate, trimethylolpropane triacrylate, trimethylolpropane EO-modified triacrylate, trimethylolpropane PO-modified triacrylate, isocyanuric acid EO-modified triacrylate, ethoxylated isocyanuric acid triacrylate, isocyanuric acid EO Modified ε-caprolactone-modified triacrylate, 1,3,5-triacryloylhexahydro-s-triazine, pentaerythritol triacrylate, dipentaerythritol triacrylate tripropionate can be used. From the viewpoint of flexibility, isocyanuric acid EO-modified triacrylate, ethoxylated isocyanuric acid triacrylate, and isocyanuric acid EO-modified ε-caprolactone-modified triacrylate are preferable.

Tetra- or higher-functional acrylates include pentaerythritol tetraacrylate, acrylate obtained by linking two molecules of ethoxylated isocyanuric acid diacrylate with hexamethylene diisocyanate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate monopropionate, and dipentaerythritol hexaacrylate. , dipentaerythritol ε-caprolactone-modified hexaacrylate, dipentaerythritol EO-modified hexaacrylate, tetramethylolmethane tetraacrylate, oligoester tetraacrylate, pentaerythritol tetraacrylate, and tris(acryloyloxy)phosphate. From the viewpoint of flexibility, dipentaerythritol EO-modified hexaacrylate is preferred.

Bifunctional methacrylates such as 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol 200 dimethacrylate, Polyethylene glycol 300 dimethacrylate, polyethylene glycol 400 dimethacrylate, polyethylene glycol #600 dimethacrylate, dipropylene glycol dimethacrylate, tripropylene glycol dimethacrylate, tetrapropylene glycol dimethacrylate, polypropylene glycol 400 dimethacrylate, polypropylene glycol 700 dimethacrylate, neo Pentyl glycol dimethacrylate, neopentyl glycol PO-modified dimethacrylate, neopentyl glycol hydroxypivalate dimethacrylate, caprolactone adduct dimethacrylate of neopentyl glycol hydroxypivalate, 1,6-hexanediol bis(2-hydroxy-3 -methacryloyloxypropyl) ether, 1,9-nonanediol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol dimethacrylate monostearate, pentaerythritol dimethacrylate monobenzoate, 2,2-bis(4-methacryloxypolyethoxyphenyl) Propane, bisphenol A dimethacrylate, EO-modified bisphenol A dimethacrylate, PO-modified bisphenol A dimethacrylate, hydrogenated bisphenol A dimethacrylate, EO-modified hydrogenated bisphenol A dimethacrylate, PO-modified hydrogenated bisphenol A dimethacrylate, bisphenol F dimethacrylate Methacrylate, EO-modified bisphenol F dimethacrylate, PO-modified bisphenol F dimethacrylate, EO-modified tetrabromobisphenol A dimethacrylate, tricyclodecane dimethylol dimethacrylate, isocyanuric acid EO-modified dimethacrylate, 2-hydroxy-1,3-dimethacrylate Roxypropane, tricyclodecanedimethanol diacrylate can be used. .

Trifunctional methacrylates such as glycerin PO-modified trimethacrylate, trimethylolethane trimethacrylate, trimethylolpropane trimethacrylate, trimethylolpropane EO-modified trimethacrylate, trimethylolpropane PO-modified trimethacrylate, isocyanuric acid EO-modified trimethacrylate, isocyanuric acid EO-modified ε-caprolactone-modified trimethacrylate, 1,3,5-trimethacryloyl hexahydro-s-triazine, pentaerythritol trimethacrylate, and dipentaerythritol trimethacrylate tripropionate can be used. From the viewpoint of flexibility, isocyanuric acid EO-modified trimethacrylate and isocyanuric acid EO-modified ε-caprolactone-modified trimethacrylate are preferred.

Tetrafunctional or higher methacrylates include pentaerythritol tetramethacrylate, dipentaerythritol pentamethacrylate monopropionate, dipentaerythritol hexamethacrylate, dipentaerythritol ε-caprolactone-modified hexamethacrylate, dipentaerythritol EO-modified hexamethacrylate, tetramethylolmethane tetra Methacrylates, oligoester tetramethacrylates, tris(methacryloyloxy)phosphates and compounds modified with ε-lactone can be used. From the viewpoint of flexibility, dipentaerythritol EO-modified hexamethacrylate is preferred.

Diamines such as ethylenediamine, 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9- diamines having linear aliphatic structures such as nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 1,14-tetradecanediamine, 1,16-hexadecanediamine; propylenediamine , 1,2-butanediamine, 1,3-butanediamine, 2,3-butanediamine, 2-methyl-1,3-propanediamine, neopentyldiamine, 1,2-pentanediamine, 3-methyl-1, diamines having a branched aliphatic structure such as 5-pentanediamine and 1,8-nonanediamine; diamines having an alicyclic structure such as cyclopropanediamine, cyclohexanediamine, cyclohexanediamine, tricyclodecanediamine and adamantyldiamine; can be used.

The protective agent preferably contains a photopolymerization initiator to promote photopolymerization of the urethane acrylate oligomer. Specific examples of the photopolymerization initiator include the following. Diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyl methyl ketal, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexyl Phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butane, oligo{2- Hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone}, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)benzyl]phenyl}-2 - acetophenones such as methylpropan-1-one; benzoins such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether; 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis( phosphines such as 2,4,6-trimethylbenzoyl)-phenylphosphine oxide; and other phenylglyoxylic methyl esters, but are not limited thereto. More specifically, Irgacure 651, Irgacure 184, Darocure 1173, Irgacure 500, Irgacure 1000, Irgacure 2959, Irgacure 907, Irgacure 369, Irgacure 379, Irgacure 1700, Irgacure 149, Irgacure Cure 1800, Irgacure 1850, Irgacure 819, Irgacure 784, Irgacure 261, Irgacure OXE-01 (CGI124), CGI242 (BASF), Adeka Optomer N1414, Adeka Optomer N1717 (ADEKA), EsACure1001M ( LAmBerti), diazonium compound publication, organic azide compounds, ortho-quinone diazides, various onium compounds including iodonium compounds, metal allene complexes, transition metal complexes containing transition metals such as ruthenium, aluminate complexes, 2, 4 ,5-triarylimidazole dimer, carbon tetrabromide, organic halogen compounds, sulfonium complexes or oxosulfonium complexes, aminoketone oxime ester compounds, and the like.

As the photopolymerization initiator, a hydrogen abstraction type radical initiator can be used, and specific examples include aromatic ketones such as acetophenone, benzophenone, benzyl, Michler's ketone, thioxanthone, and anthraquinone. , but not limited to. These compounds are generally used in combination with tertiary amines in the technical field, specifically trimethylamine, triethylamine, tripropylamine, tributylamine, N-methyldiethanolamine, p-dimethylaminophenylalkyl Examples include, but are not limited to, esters and the like.

Moreover, it is also possible to use a photobase generator, a photoacid generator, etc. as a photoinitiator. These may be used individually by 1 type, and may be used 2 or more types by arbitrary ratios.

Although the photobase generator is not particularly limited, for example, various compounds that generate primary amines, secondary amines or tertiary amines, such as cobalt amine complexes, o-acyloximes, carbamic acid derivatives, formamide derivatives, sulfonamides (e.g., N-cyclohexyl-4-methylphenylsulfonamide, etc.), quaternary ammonium salts, tosylamine, carbamates (e.g., 2-nitrobenzylcarbamate, 2,5-dinitrobenzylcyclohexylcarbamate, 1,1-dimethyl-2-phenylethyl-N-isopropylcarbamate, etc.), amine imide compounds, compounds having an amidine structure, α-aminoacetophenone, and the like. A photobase generator can be used individually or in combination of 2 or more types.

Examples of photoacid generators include, but are not limited to, diazonium salts, iodonium salts, sulfonium salts, phosphonium salts, selenium salts, metallocene complexes, oxathiazole derivatives, s-triazine derivatives, imide compounds, oxime sulfonates, diazonaphthoquinones, and sulfonic acids. ester [1-phenyl-1-(4-methylphenyl)sulfonyloxy-1-benzoylmethane, 1,2,3-trisulfonyloxymethylbenzene, 1,3-dinitro-2-(4-phenylsulfonyloxymethyl) Benzene, 1-phenyl-1-(4-methylphenyl)sulfonyloxymethyl-1-hydroxy-1-benzoylmethane, disulfone derivatives (diphenyldisulfone, etc.), benzoin tosylate, etc.] and Lewis acid salts (triphenylsulfonium hexafluoro Antimony, triphenylsulfonium hexafluorophosphate, triphenylsulfonium methanesulfonyl, diphenyliodine hexafluorophosphate and the like can be used.

As the photopolymerization initiator, among these, acetophenones, phosphine oxides and the like can be preferably used.

The photopolymerization initiators can be used singly or in combination, and can be optionally mixed depending on the properties required for the reaction cured product and the compounds to be cured by active energy rays. When these photopolymerization initiators are used, the amount used is preferably 0.1 to 50 parts by mass with respect to 100 parts by mass of the total solid content of the urethane acrylate oligomer.

Additionally, a sensitizer can be included. Examples of sensitizers include unsaturated ketones such as chalcone derivatives and dibenzalacetone, 1,2-diketone derivatives such as benzyl and camphorquinone, benzoin derivatives, fluorene derivatives, naphthoquinone derivatives, and anthraquinone. derivatives, xanthene derivatives, thioxanthene derivatives, xanthone derivatives, thioxanthone derivatives, coumarin derivatives, ketocoumarin derivatives, cyanine derivatives, merocyanine derivatives, polymethine dyes such as oxonol derivatives, acridine derivatives, azine derivatives, thiazine derivatives, oxazine derivatives, indoline derivatives , azulene derivatives, azulenium derivatives, squarylium derivatives, porphyrin derivatives, tetraphenylporphyrin derivatives, triarylmethane derivatives, tetrabenzoporphyrin derivatives, tetrapyrazinoporphyrazine derivatives, phthalocyanine derivatives, tetraazaporphyrazine derivatives, tetraquinoxalyloporphyrazine derivatives, naphthalocyanine derivatives, subphthalocyanine derivatives, pyrylium derivatives, thiopyrylium derivatives, tetraphylline derivatives, annulene derivatives, spiropyran derivatives, spirooxazine derivatives, thiospiropyran derivatives, metal arene complexes, organic ruthenium complexes, Michler ketone derivatives, biimidazole derivatives, etc. include, but are not limited to.

A urethane acrylate oligomer having a polyoxyalkylene chain can be obtained by reacting various polyvalent isocyanates with an acrylic or methacrylic acid ester having a polyoxyalkylene chain.
Specific examples of acrylic acid esters or methacrylic acid esters having a polyoxyalkylene chain include BLEMMER PE-90, BLEMMER PE-200, BLEMMER PE-350, BLEMMER AE, which are commercially available products manufactured by NOF Corporation. -90, Blenmer AE-200, Blenmer AE-350, Blenmer PP-500, Blenmer PP-800, Blenmer PP-1000, Blenmer AP-400, Blenmer AP-550, Blenmer AP-800, Blenmer 700PEP-350B, Blenmer 10PEP -550B, Blenmer 55PET-400, Blenmer 30PET-800, Blenmer 55PET-800, Blenmer 30PPT-800, Blenmer 50PPT-800, Blenmer 70PPT-800, Blenmer PME-100, Blenmer PME-200, Blenmer PME-400, Blenmer PME -1000, Blenmer PME-4000, Blenmer AME-400, Blenmer 50POEP-800B, Blenmer 50AOEP-800B, Blenmer AEP, Blenmer AET, Blenmer APT, Blenmer PLE, Blenmer ALE, Blenmer PSE, Blenmer ASE, Blenmer PKE, Blenmer AKE, BLEMMER PNE, BLEMMER ANE, BLEMMER PNP, BLEMMER ANP, BLEMMER PNEP-600; LIGHT ESTER 130MA, LIGHT ESTER 041MA, LIGHT ESTER MTG, LIGHT ACRYLATE EC-A, LIGHT ACRYLATE MTG manufactured by Kyoeisha Chemical Co., Ltd. -A, light acrylate 130A, light acrylate DPM-A, light acrylate P-200A, light acrylate NP-4EA, light acrylate NP-8EA, light acrylate EHDG-A; MA, a commercial product manufactured by Nippon Nyukazai Co., Ltd. -30, MA-50, MA-100, MA-150, RMA-1120, RMA-564, RMA-568, RMA-506, MPG130-MA, AntoxMS-60, MPG-130MA, RMA-150M, RMA-300M , RMA-450M, RA-1020, RA-1120, RA-1820; NK-ESTERM-20G, M-40G, M-90G, M-230G, AMP, which are commercially available products manufactured by Shin Nakamura Chemical Co., Ltd. -10G, AMP-20G, AMP-60G, AM-90G, LA; Sanyo Chemical Eleminol RS-30, RS-3000, etc., which are commercially available products manufactured by Sei Co., Ltd., can be mentioned.

(Additives, etc.)
The active energy ray composition can be adjusted to a suitable viscosity by dilution with a solvent, and if necessary, inorganic fillers, organic fillers, pigments, film-forming aids, flame retardants, and light diffusion commonly used in paints. Agents, plasticizers, solvents, dispersants, wetting agents, thickeners, preservatives, fungicides, light stabilizers, UV absorbers, antifoaming agents and the like can be added. As the flame retardant, an aluminum phosphate-based flame retardant is preferable.

Specific examples of inorganic fillers include inorganic fillers containing oxides, hydroxides, sulfates, carbonates, silicates, and the like of metals such as magnesium, calcium, barium, zinc, zirconium, molybdenum, silicon, and antimony. fine particles. More detailed specific examples include inorganic silica gel containing silica, silica gel, aluminum oxide, aluminum hydroxide, calcium hydroxide, calcium carbonate, magnesium oxide, magnesium hydroxide, aluminosilicate, talc, mica, glass fiber, glass powder, and the like. system particles. One type of inorganic filler may be used, or two or more types may be used in combination.

Specific examples of organic fillers include polytetrafluoroethylene resin, polyethylene resin, polypropylene resin, polymethyl methacrylate resin, polystyrene resin, polyamide resin, melamine resin, guanamine resin, phenol resin, urea resin, silicone resin, methacrylate resin, Examples include polymer fine particles such as acrylate resin, cellulose powder, nitrocellulose powder, wood powder, waste paper powder, shell powder, and starch. One type of organic filler may be used, or two or more types may be used in combination.

The insulating layer 12 is made of polyimide having an aromatic ring concentration of 30% by mass or less (hereinafter also referred to as "specific polyimide") and polyamide having an aromatic ring concentration of 30% by mass or less (hereinafter also referred to as "specific polyamide"). It may be formed of a resin containing at least one selected from the group as a main component. That is, the resin constituting the insulating layer 12 may contain only the specific polyimide as a main component, may contain only a specific polyamide as a main component, or may contain a combination of the specific polyimide and the specific polyamide as the main component. may contain.

(Aromatic ring concentration)
In the present specification, the aromatic ring concentration refers to the content of aromatic rings contained in polyimide or polyamide (hereinafter also simply referred to as "polymer") (the ratio of the mass of aromatic rings in the raw material of the polymer), and the aromatic ring concentration in the polymer It refers to the value obtained by dividing the weight of the portion corresponding to the ring (hereinafter referred to as "aromatic ring skeleton") by the weight of the entire polymer. That is, the aromatic ring concentration is a value calculated from the composition of the monomer components used as raw materials for the polymer. Specifically, the aromatic ring concentration is calculated by the following formula (1).
Aromatic ring concentration (% by mass)=[“molecular weight of aromatic ring skeleton”דnumber of aromatic ring skeletons contained in polymer (polyimide or polyamide)”]/[molecular weight of polymer (polyimide or polyamide)] (Formula 1).

In addition, the molecular weight of the polymer in Formula (1) is a number average molecular weight (Mn). Further, the aromatic ring skeleton in the formula (1) includes a condensed benzene ring skeleton (molecular weight: 76 g/mol), a condensed naphthalene ring skeleton (molecular weight: 128 g/mol), a condensed anthracene ring skeleton (molecular weight: 178 g/mol), A condensed aromatic ring skeleton such as a condensed phenanthrene ring skeleton (molecular weight: 178 g/mol). Condensed naphthalene ring skeletons, condensed anthracene ring skeletons, and condensed phenanthrene ring skeletons are each treated as one condensed aromatic ring skeleton to calculate the aromatic ring concentration.

The aromatic ring concentration is 30% by mass or less, preferably 20% by mass or less, from the viewpoint of improving the tracking resistance of the insulating pressure-sensitive adhesive tape. The lower limit of the aromatic ring concentration is preferably 5% by mass or more, more preferably 7% by mass or more, and even more preferably 8% by mass or more, from the viewpoint of improving the heat resistance of the insulating pressure-sensitive adhesive tape. In other words, the aromatic ring concentration is preferably 5% by mass or more and 30% by mass or less, more preferably 7% by mass or more and 20% by mass or less, from the viewpoint of obtaining an insulating adhesive tape having both tracking resistance and heat resistance. More preferably, it is 8% by mass or more and 20% by mass or less.

(Functional group concentration (functional group value))
The functional group concentration (acid value or acid anhydride value) of the polymer is not particularly limited, but from the viewpoint of making the weight average molecular weight (Mw) of the polymer within the above range, it is preferably 22 mgKOH/g or less, more preferably 14 mgKOH/g or less. , more preferably 11 mgKOH/g or less, more preferably 8 mgKOH/g or less. Moreover, the lower limit is preferably 5 mgKOH/g or more, more preferably 6 mgKOH/g or more, from the above viewpoint. The functional group concentration can be measured by the method described in Examples below.

[Polyimide having an aromatic ring concentration of 30% by mass or less]
Polyimides (specific polyimides) having an aromatic ring concentration of 30% by mass or less can be prepared from various tetracarboxylic dianhydrides and polyamine compounds as raw materials, provided that the ratio of structures derived from aromatic rings to the entire polymer is 30% by mass or less. etc. can be combined.

(tetracarboxylic dianhydride)
A tetracarboxylic dianhydride having an aliphatic structure or an alicyclic structure is suitable because it is easy to adjust the aromatic ring concentration to 30% by mass or less relative to the entire polymer.

Tetracarboxylic dianhydrides having an aliphatic structure include, for example, 1,2,3,4-butanetetracarboxylic acid, 1,2,3,4-pentanetetracarboxylic acid, 1,2,4,5- Examples include tetracarboxylic dianhydrides having a chain hydrocarbon structure such as pentanetetracarboxylic acid, 1,2,3,4-hexanetetracarboxylic acid, and 1,2,5,6-hexanetetracarboxylic acid.

Examples of tetracarboxylic dianhydrides having an alicyclic structure include cyclobutane-1,2,3,4-tetracarboxylic acid, cyclopentane-1,2,3,4-tetracarboxylic acid, cyclohexane-1, 2,3,4-tetracarboxylic acid, cyclohexane-1,2,4,5-tetracarboxylic acid, 1-carboxymethyl-2,3,5-cyclopentanetricarboxylic acid, 3-(carboxymethyl)-1,2 ,4-cyclopentanetricarboxylic acid (TCA), rel-dicyclohexyl-3,3′,4,4′-tetracarboxylic acid, tricyclo[4.2.2.02,5]dec-9-ene-3,4 , 7,8-tetracarboxylic acid, 5-carboxymethylbicyclo[2.2.1]heptane-2,3,6-tricarboxylic acid, bicyclo[2.2.1]heptane-2,3,5,6- Tetracarboxylic acid, bicyclo[2.2.2]oct-7-ene-2,3,6,7-tetracarboxylic acid, bicyclo[3.3.0]octane-2,4,6,7-tetracarboxylic acid acid, 7,8-diphenylbicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic acid, 4,8-diphenyl-1,5-diazabicyclooctane-2, 3,6,7-tetracarboxylic acid, 9-oxatricyclo[4.2.1.02,5]nonane-3,4,7,8-tetracarboxylic acid, 9,14-dioxopentacyclo[8 .2.11,11.14,7.02,10.03,8]tetradecane-5,6,12,13-tetracarboxylic acids such as cyclo, bicyclo, tricyclotetracarboxylic acids; 4.5] Spiro ring-containing tetracarboxylic acids such as decane-1,3,7,9-terotone; Furanyl)naphtho[1,2-c]furan-1,3-dione (TDA) and other tetracarboxylic acid dianhydrides having an alicyclic hydrocarbon structure.

As the tetracarboxylic dianhydride other than the aliphatic structure or the alicyclic structure, a tetracarboxylic dianhydride having an aromatic structure may be used as long as the aromatic ring concentration can be adjusted to 30% by mass or less. Specific examples include pyromellitic dianhydride (PMDA), 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA), 1,2,3,4-benzenetetracarboxylic dianhydride 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, diphthalic dianhydride and the like. Among these, PMDA and BPDA are preferred.

The tetracarboxylic dianhydrides having an aliphatic structure, an alicyclic structure, or an aromatic structure may be used alone, or two or more of them may be used in combination. Moreover, the examples of the monomers may appropriately have a substituent. Examples of substituents include alkyl groups, halogen atoms, nitro groups, and cyano groups. Moreover, instead of the tetracarboxylic dianhydride, a tetracarboxylic acid having a similar structure or a tetracarboxylic acid derivative such as a tetracarboxylic acid diester may be used.

(Polyamine compound)
As with the tetracarboxylic dianhydride, polyamine compounds having an aliphatic structure or an alicyclic structure are suitable because the aromatic ring concentration relative to the entire polymer can be easily adjusted to 30% by mass or less. Among them, dimer diamine (DDA), which is a polyamine compound having a dimer structure, is preferable.

A dimer diamine can be a compound obtained by converting the carboxyl group of a dimer acid to an amino group. A dimer acid is a polybasic acid compound having a dimer structure, and is a dimer of fatty acids (hereinafter referred to as "fatty acid dimer").

The fatty acid dimer is preferably a compound having 20 to 60 carbon atoms, more preferably a compound having 24 to 56 carbon atoms, still more preferably a compound having 28 to 48 carbon atoms, and even more preferably a compound having 36 to 44 carbon atoms. The fatty acid dimer is preferably a dicarboxylic acid compound having a branched structure obtained by Diels-Alder reaction of fatty acid. The fatty acid is preferably, for example, an unsaturated fatty acid having 10 to 30 carbon atoms, more preferably an unsaturated fatty acid having 10 to 24 carbon atoms. The unsaturated fatty acid has one or more carbon-carbon double bonds or carbon-carbon triple bonds. Specific examples of the fatty acid include natural fatty acids such as soybean oil fatty acid, tall oil fatty acid, and rapeseed oil fatty acid, and oleic acid, linoleic acid, linolenic acid, erucic acid, and the like obtained by refining these fatty acids. The branched structure is preferably an aliphatic chain structure or a ring structure, more preferably a ring structure. The ring structure is preferably one or two or more aromatic rings and an alicyclic structure, more preferably one or two or more alicyclic structures. The alicyclic structure may have one double bond in the ring, or may have no double bond.

When synthesizing fatty acid dimers, fatty acid trimers and, in some cases, tetramers are produced in addition to fatty acid dimers. Therefore, a polybasic acid compound containing a dimer skeleton is a mixture containing not only a fatty acid dimer as a main component but also a fatty acid trimer and the like as a raw material in some cases. The content of fatty acid dimers in the dimer acid is preferably 70% by mass or more, more preferably 90% by mass or more, and still more preferably 95% by mass or more.

Since dimer acid uses unsaturated fatty acids as raw materials, unsaturated bonds may remain. In such a case, hydrogenation (also referred to as hydrogenation reaction) can be performed to suppress the number of unsaturated bonds. This improves the reaction stability when synthesizing the specific polyimide, and further improves the heat resistance of the insulating adhesive tape containing the specific polyimide.

Commercial products of dimer acid include, for example, Croda Japan Co., Ltd. "Pripol 1004", "Pripol 1006", "Pripol 1009", "Pripol 1013", "Pripol 1015", "Pripol 1017", "Pripol 1022", " Pripol 1025", "Pripol 1040"; BASF Japan's "Enpol 1008", "Enpol 1012", "Enpol 1016", "Enpol 1026", "Enpol 1028", "Enpol 1043", "Enpol 1061", " Enpol 1062" and the like. Each of these may be used alone, or two or more of them may be used in combination.

The dimer diamine is preferably a compound having 20 to 60 carbon atoms, more preferably a compound having 24 to 56 carbon atoms, still more preferably a compound having 28 to 48 carbon atoms, and even more preferably a compound having 36 to 44 carbon atoms. A dimer diamine having such a carbon number is preferable from the viewpoint of availability.

Commercial products of dimer diamine (DDA) include, for example, Croda Japan's "PRIAMINE 1071", "PRIAMINE 1073", "PRIAMINE 1074", "PRIAMINE 1075", BASF Japan's "Versamin 551", and the like. is mentioned. Each of these may be used alone, or two or more of them may be used in combination.

In addition, the structure of the polybasic acid compound having a dimer structure for obtaining the dimer diamine may be plural in the synthesis process, but is not limited to the structure.

Polyamine compounds other than dimer diamine (hereinafter also referred to as "other diamines") are not particularly limited. , a chain hydrocarbon structure and/or an alicyclic hydrocarbon structure), and a diamine compound having an aromatic structure (an aromatic ring and the above structure may be combined arbitrarily).

The dimer structure (dimer diamine) and the polyamine compound other than dimer diamine (other diamine) may be used alone, or two or more of them may be used in combination.

(Other monomers)
As a raw material for the resin component that constitutes the insulating layer 12, monomers other than those described above may be used within a range that does not hinder the object of the present invention. For example, a polyamine compound having three or more amino groups may be used. Examples of polyamine compounds having three or more amino groups include 1,2,4-triaminobenzene and 3,4,4'-triaminodiphenyl ether.

(crosslinking agent)
The heat resistance of the insulating layer 12 can be improved by cross-linking the specific polyimide by reacting it with a cross-linking agent. Therefore, it is preferable that the monomer component used as the raw material of the specific polyimide contains a cross-linking agent.

Examples of the cross-linking agent include compounds having two or more reactive functional groups in one molecule and capable of constructing a cross-linked structure. Specific examples include epoxy compounds, cyanate ester compounds, isocyanate group-containing compounds, chelate compounds, carbodiimide group-containing compounds, and the like.

An epoxy compound refers to a compound having two or more epoxy groups in one molecule, and known compounds can be used.

Examples of epoxy compounds include bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, novolak type epoxy resin, dicyclopentadiene type epoxy resin, polyfunctional phenol type epoxy resin, naphthalene type epoxy resin, aralkyl-modified type epoxy resins, alicyclic and alcohol-based glycidyl ethers, alicyclic and alcohol-based glycidyl amines (e.g., Mitsubishi Gas Chemical Co., Ltd. "Tetrad C", "Tetrad X", etc.) , and alicyclic and alcohol-based glycidyl ester-based resins.

The cross-linking agent may be a low-molecular-weight compound or a high-molecular-weight compound. The cross-linking agent may be a compound that itself exhibits thermosetting properties, or a compound that cross-links the cross-linking agent and the specific polyimide. The cross-linking agents may be used alone or in combination of two or more.

(functional group)
The specific polyimide preferably has a functional group because the heat resistance can be improved by reacting with the cross-linking agent to cross-link the polyimide.

A carboxyl group, an amino group, a hydroxyl group, an acid anhydride group, etc. can be illustrated as a functional group. These may be functional groups derived from monomers used as raw materials for specific polyimides, or functional groups may be introduced as modified products after the polymer is obtained. The functional group may be present at the end of the polymer, or it may be present at a side group and/or a side chain. A preferred example is a mode having a functional group such as a carboxyl group, an acid anhydride group or an amino group at the polymer terminal. Moreover, the aspect which has at least 1 type of functional groups, such as a carboxyl group, an amino group, a hydroxyl group, in a side group or a side chain can be illustrated.

When having a hydroxyl group as a functional group, a phenolic hydroxyl group is preferred. By having a phenolic hydroxyl group, it is possible to build a crosslinked structure with a crosslinking agent and form a tough insulating layer. A phenolic hydroxyl group can be easily introduced by using a polybasic acid compound having a phenolic hydroxyl group and/or a polyamine compound having a phenolic hydroxyl group. The aromatic ring of this phenolic hydroxyl group is preferably contained in the main chain skeleton. Moreover, it is preferable to use a polybasic acid compound having a phenolic hydroxyl group.

(catalyst)
A catalyst may be used when the specific polyimide and the cross-linking agent are reacted and cross-linked. Examples of the catalyst include aliphatic tertiary amines such as triethylamine; aromatic tertiary amines such as dimethylaniline; heterocyclic tertiary amines such as pyridine, picoline and isoquinoline; . Specific examples include 1,8-diazabicyclo[5,4,0]-undecene-7 (DBU) and triphenylphosphine (TPP).

[Method for producing polyimide having an aromatic ring concentration of 30% by mass or less]
A polyimide having an aromatic ring concentration of 30% by mass or less (specific polyimide) can be produced by various known methods. A specific example is a method of cyclizing a polyamic acid resin or a polyamic acid ester resin, which is a polyimide precursor, by heating to convert it into an imide group.

Methods for synthesizing the polyamic acid resin include, for example, a method of reacting a tetracarboxylic dianhydride and a diamine. Specifically, a monomer component containing a tetracarboxylic dianhydride and a diamine is dissolved in a solvent, for example, by stirring at a temperature of 60 to 120° C. for 0.1 to 2 hours to polymerize the polyimide. A polyamic acid resin, which is a precursor, can be produced.

Polyamic acid ester resin synthesis method, for example, a method of obtaining a diester with tetracarboxylic dianhydride and alcohol, then reacting with diamine in the presence of a condensing agent; diester with tetracarboxylic dianhydride and alcohol is obtained, then the remaining dicarboxylic acid is acid-chlorinated and reacted with a diamine. Thereby, a polyamic acid ester resin, which is a polyimide precursor, can be produced.

Examples of organic solvents used for polymerization include N-methyl-2-pyrrolidone (NMP), 2-butanone, dimethylsulfoxide (DMSO), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc ), N,N-diethylacetamide, hexamethylphosphoramide, N-methylcaprolactam, dimethyl sulfate, cyclohexanone, dioxane, tetrahydrofuran, diglyme, triglyme, cresol and the like. Each of the organic solvents may be used alone, or two or more of them may be used in combination. The organic solvent can also be used in combination with an aromatic hydrocarbon such as xylene or toluene.

The method of cyclizing the polyimide precursor by heating to convert it to an imide group, that is, the method of imidizing the polyimide precursor to obtain a polyimide resin is not particularly limited, but in a solvent, for example, at a temperature of 80 to 400 ° C. A method of heating for 0.5 to 50 hours can be exemplified. At this time, a catalyst and/or a dehydrating agent may be used as necessary.

Examples of catalysts include aliphatic tertiary amines such as triethylamine; aromatic tertiary amines such as dimethylaniline; and heterocyclic tertiary amines such as pyridine, picoline and isoquinoline. Examples of dehydrating agents include aliphatic acid anhydrides such as acetic anhydride and aromatic acid anhydrides such as benzoic anhydride.

The imidization rate (imido ring formation rate) of the specific polyimide is not particularly limited, but from the viewpoint of forming an insulating layer that imparts excellent tracking resistance to the base layer, it is preferably 80% or more, more preferably 90%. Above, more preferably 95 to 100%. The imidization rate can be determined by NMR or IR analysis.

[Polyamide having an aromatic ring concentration of 30% by mass or less]
A polyamide (specified polyamide) having an aromatic ring concentration of 30% by mass or less is a polymer containing a repeating structural unit containing an amide group. Specifically, the specific polyamide is a polymer of a polybasic acid compound, a polyamine compound, and optionally other monomers, or a modified product obtained by modifying the polymer. Here, the modified product is a derivative obtained by partially changing the molecular structure of the polymer (for example, changing the functional group, substituting with another compound, or adding another compound). The specific polyamide can be combined with various polybasic acid compounds, polyamine compounds, and the like as raw materials as long as the ratio of the aromatic ring-derived structure to the entire polymer is 30% by mass or less.

In order to adjust the aromatic ring concentration to 30% by mass or less, a method of introducing a dimer structure into the polyamide resin is preferable. A monomer having a dimer structure may be used to introduce the dimer structure into the polyamide resin. A dimer acid is suitable as the polybasic acid compound having a dimer structure. Examples of the dimer acid include those similar to the fatty acid dimer exemplified for the specific polyimide. A dimer diamine is suitable as the polyamine compound having a dimer structure. Examples of the dimer diamine include the same dimer diamines as exemplified for the specific polyimide.

(Polybasic acid compound)
A polybasic acid compound is a dibasic or higher carboxylic acid. A part of the polybasic acid compound may be an acid anhydride. Examples of polybasic acid compounds include the aforementioned dimer acids and other polybasic acid compounds.

The other polybasic acid compound is a polybasic acid compound other than the dimer acid and has a functionality of two or more.

Dibasic acid compounds such as phthalic acid, isophthalic acid, terephthalic acid (TPA), 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, benzophenone-4,4'-dicarboxylic acid, 4,4' - aromatic dibasic acids such as biphenyldicarboxylic acid; oxalic acid, malonic acid, methylmalonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, malic acid, tartaric acid, thiomalic acid, pimelic acid, suberin acids, azelaic acid, sebacic acid, dodecanedioic acid, hexadecanedioic acid, diglycolic acid and other aliphatic dibasic acids; 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid Alicyclic dibasic acids such as acids and the like are included. Among the diacid compounds, isophthalic acid, terephthalic acid (TPA) and 1,4-cyclohexanedicarboxylic acid are preferred.

Trifunctional or higher polybasic acid compounds include, for example, trimellitic acid, hydrogenated trimellitic acid, pyromellitic acid, hydrogenated pyromellitic acid, trimesic acid, 1,4,5,8-naphthalenetetracarboxylic acid, and the like. be done.

In addition, preferred examples of other polybasic acid compounds include polybasic acid compounds having phenolic hydroxyl groups. A tough insulating layer can be formed by using a polybasic acid compound having a phenolic hydroxyl group. A polybasic acid compound having a phenolic hydroxyl group is a compound having a phenolic hydroxyl group and two or more acidic functional groups. Examples of the acidic functional group include a carboxyl group.

Polybasic acid compounds having a phenolic hydroxyl group include monohydroxyisophthalic acids such as 2-hydroxyisophthalic acid, 4-hydroxyisophthalic acid, and 5-hydroxyisophthalic acid (5-HIP); 2,5-dihydroxyisophthalic acid; dihydroxyisophthalic acid such as 2,4-dihydroxyisophthalic acid and 4,6-dihydroxyisophthalic acid; monohydroxyterephthalic acid such as 2-hydroxyterephthalic acid; Dihydroxyterephthalic acid; hydroxyphthalic acids such as 3-hydroxyphthalic acid and 4-hydroxyphthalic acid; 3,4-dihydroxyphthalic acid, 3,5-dihydroxyphthalic acid, 4,5-dihydroxyphthalic acid, 3,6-dihydroxy Dihydroxyphthalic acid such as phthalic acid and the like are included. Among these, 5-hydroxyisophthalic acid (5-HIP) is preferred in terms of copolymerizability and availability. In the polybasic acid compound having a phenolic hydroxyl group, the carboxyl groups of the compounds exemplified above may form an acid anhydride group, or the carboxyl groups may form an ester.

The dimer acid and other polybasic acid compounds exemplified as polybasic acid compounds may be used alone, or two or more of them may be used in combination.

(crosslinking agent)
The heat resistance of the insulating layer can be improved by cross-linking the specific polyamide by reacting it with a cross-linking agent. Therefore, it is preferable that the monomer component used as the raw material of the specific polyamide contains a cross-linking agent. Examples of the cross-linking agent include the same cross-linking agents as those exemplified for the specific polyimide.

(functional group)
The specific polyamide preferably has a functional group because it can be crosslinked by reacting with the crosslinking agent to improve heat resistance. Examples of the functional group include the same functional groups as those exemplified for the specific polyimide, and a phenolic hydroxyl group is preferred.

(others)
The specific polyamide may be a polyamide-imide having an imide group in part, or a polyamide ester having an ester group in part, as long as the object of the present invention is not impaired.

[Method for producing a polyamide having an aromatic ring concentration of 30% by mass or less]
A polyamide (specific polyamide) having an aromatic ring concentration of 30% by mass or less can be produced by various known methods. Specific examples thereof include melt polymerization, interfacial polymerization, solution polymerization, bulk polymerization, solid phase polymerization, or a combination thereof. Among these, solution polymerization is preferred.

Polymerization of the specific polyamide can be carried out in the presence or absence of a catalyst using a monomer component containing a polybasic acid compound, a polyamine compound, and optionally other monomers. . For example, predetermined amounts of dimer acid, other acid monomers, dimer diamines, other amine-based monomers, and ion-exchanged water are placed in a nitrogen-filled flask, and the mixture is uniformly dissolved or dispersed by heating and stirring at 20 to 100°C. After that, the temperature is gradually raised to 230° C. while removing the ion-exchanged water and the water generated by the reaction, and the pressure is reduced to about 15 mmHg when the temperature reaches 230° C., and this state is maintained for about 1 hour to obtain the specific polyamide. be able to. The heating temperature is, for example, 150-300.degree. The heating time is about 1 to 24 hours. It is preferable to carry out dehydration or dealcoholization reaction in order to promote the synthesis reaction. Moreover, in order to avoid coloring and decomposition reaction due to high temperature, it is preferable to carry out the reaction at 180 to 270° C. under reduced pressure.

A specific polyimide and a specific polyamide may be used alone, respectively, or two or more of them may be used in combination. Among the specific polyimide and the specific polyamide, the specific polyimide is more preferable from the viewpoint of obtaining an insulating pressure-sensitive adhesive tape having both tracking resistance and heat resistance.

The resin component that constitutes the insulating layer may contain other resins than the specific polyimide and specific polyamide within a range that does not hinder the object of the present invention. Other resins that can be used together with the specific polyimide and/or the specific polyamide include fluororesins and the like.

The insulating composition containing the specific polyimide and / or specific polyamide, in addition to being able to adjust the viscosity suitable for the above-mentioned crosslinking agent and solvent, if necessary, usually used in paint inorganic fillers, organic fillers, Add pigments, film forming aids, flame retardants, light diffusing agents, plasticizers, dispersants, wetting agents, thickeners, preservatives, antifungal agents, light stabilizers, ultraviolet absorbers, antifoaming agents, etc. can be done. As the flame retardant, an aluminum phosphate-based flame retardant is preferred.

[Adhesive layer]
The adhesive layer is formed by applying and curing an adhesive composition, and is a layer for imparting adhesiveness. As shown in FIG. 1B, the insulating layer 12 of the insulating adhesive tape 1 constitutes the other outermost layer, and is subdivided into an adhesive impregnated layer 13b impregnated with the glass cloth layer 11 and an adhesive non-impregnated layer 13a that is not impregnated. be. When the insulating layer 12 is completely impregnated with the glass cloth layer, the adhesive impregnation layer 13b may not exist.

The adhesive composition for forming the adhesive layer mainly contains an adhesive, and examples of the adhesive include acrylic adhesives, silicone adhesives, rubber adhesives, urethane adhesives, and the like. Each of these may be used alone, or two or more of them may be used in combination. Among these, silicone pressure-sensitive adhesives are preferable from the viewpoint of heat resistance. Acrylic adhesives are more preferred. A pressure-sensitive adhesive composition is obtained by adding a cross-linking agent, additives, etc. to the pressure-sensitive adhesive as necessary and thoroughly mixing them. Further, the viscosity can be adjusted to be suitable for coating by dilution with a solvent.

Materials known as silicone resins can be used as the silicone pressure-sensitive adhesive. Specifically, an organopolysiloxane having silanol groups at both ends of the molecular chain is combined with a triorganosiloxane represented by R3SiO0.5 (wherein R represents a substituted or unsubstituted monovalent hydrocarbon group) in the molecule. Examples thereof include those obtained by partial dehydration condensation of organopolysiloxanes having units and SiO2 units. These are available as silicone adhesives KR-101-10, KR-120, KR-130 and X-40-3068 (all manufactured by Shin-Etsu Chemical Co., Ltd.). There are generally two curing methods for silicone-based adhesives, one using a peroxide such as benzoyl peroxide and the other using a reaction between a platinum catalyst and an organopolysiloxane having Si—H bonds. Can be used and can be used together.

The acrylic pressure-sensitive adhesive preferably contains a (meth)acrylic acid ester polymer. In other words, the adhesive composition used as a raw material for the acrylic adhesive contains a (meth)acrylic acid ester polymer. In addition, in this specification, (meth)acrylic acid means acrylic acid and/or methacrylic acid. In addition, in this specification, the concept of "copolymer" is also included in "polymer".

((Meth) acrylic acid ester polymer)
The (meth)acrylic acid ester polymer contains, as a monomer unit constituting the polymer, a (meth)acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms,
Desirable adhesiveness can be expressed. The (meth)acrylic acid alkyl esters include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate [BA, BMA], (meth) ) n-pentyl acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate [2-EHA, 2-EHMA], isooctyl (meth)acrylate, n-decyl (meth)acrylate, Examples include n-dodecyl (meth)acrylate, myristyl (meth)acrylate, palmityl (meth)acrylate, and stearyl (meth)acrylate. Each of these may be used alone, or two or more of them may be used in combination. Among these, from the viewpoint of improving the adhesiveness of the insulating adhesive tape, (meth)acrylic acid esters having an alkyl group having 1 to 8 carbon atoms are preferable, and (meth)acrylic acid n-butyl [BA, BMA] and 2-Ethylhexyl (meth)acrylate [2-EHA, 2-EHMA] is more preferred, and n-butyl acrylate [BA] and 2-ethylhexyl acrylate [2-EHA] are even more preferred.

The (meth)acrylic acid ester polymer preferably contains 50% by mass or more of a (meth)acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms as a monomer unit constituting the polymer, and 60 mass%. % or more, more preferably 70 mass % or more. By containing 50% by mass or more of the (meth)acrylic acid alkyl ester, the (meth)acrylic acid ester polymer can exhibit suitable adhesiveness. Further, the (meth)acrylic acid ester polymer preferably contains 90% by mass or less of a (meth)acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms as a monomer unit constituting the polymer, It is more preferable to contain 80% by weight or less. By containing 90% by mass or less of the (meth)acrylic acid alkyl ester, a suitable amount of other monomer components can be introduced into the (meth)acrylic acid ester polymer.

The (meth)acrylic acid ester polymer has a reactive functionality for imparting adhesive properties and cohesion to the (meth)acrylic acid alkyl ester having 1 to 20 carbon atoms in the main alkyl group constituting the polymer. It is preferably a copolymer obtained by copolymerizing a monomer containing a group (hereinafter referred to as "monomer containing a reactive functional group").

Examples of reactive functional group-containing monomers include monomers having a carboxy group in the molecule (hereinafter referred to as "carboxy group-containing monomer"), monomers having a hydroxyl group in the molecule (hereinafter referred to as "hydroxyl group-containing monomer"), and amino groups in the molecule. (hereinafter referred to as "amino group-containing monomer") and the like. Each of these may be used alone, or two or more of them may be used in combination.

Carboxy group-containing monomers include, for example, ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. Each of these may be used alone, or two or more of them may be used in combination. Among these, acrylic acid is preferred. According to acrylic acid, the above effects are more excellent.

The (meth)acrylic acid ester polymer preferably contains 0.5% by mass or more of a carboxy group-containing monomer, more preferably 1% by mass or more, as a monomer unit constituting the polymer, and 3% by mass. % or more is more preferable. Further, the (meth)acrylic acid ester polymer preferably contains 30% by mass or less, more preferably 25% by mass or less, of a carboxy group-containing monomer as a monomer unit constituting the polymer. % or less is more preferable.

Examples of hydroxyl group-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, (meth) ) hydroxyalkyl (meth)acrylates such as 3-hydroxybutyl acrylate and 4-hydroxybutyl (meth)acrylate; Each of these may be used alone, or two or more of them may be used in combination.

Examples of amino group-containing monomers include aminoethyl (meth)acrylate and n-butylaminoethyl (meth)acrylate. Each of these may be used alone, or two or more of them may be used in combination.

The polymerization mode of the (meth)acrylic acid ester polymer may be a random copolymer or a block copolymer.

The weight average molecular weight of the (meth)acrylic acid ester polymer is preferably 200,000 or more, more preferably 300,000 or more, more preferably 300,000 or more, from the viewpoint of improving the heat resistance, solvent resistance, adhesive properties, and durability of the pressure-sensitive adhesive. is 400,000 or more, and even more preferably 500,000 or more. The upper limit is preferably 2,500,000 or less, more preferably 2,000,000 or less, even more preferably 1,500,000 or less, and even more preferably 1,200,000 or less, from the viewpoint of improving the adhesive strength of the resulting adhesive. In addition, the weight average molecular weight in this specification is the value of standard polystyrene conversion measured by the gel permeation chromatography (GPC) method.

(crosslinking agent)
The cross-linking agent may be one that reacts with the reactive functional group of the (meth)acrylic acid ester polymer. Examples include isocyanate cross-linking agents, epoxy cross-linking agents, amine cross-linking agents, melamine cross-linking agents, Examples include aziridine-based cross-linking agents, hydrazine-based cross-linking agents, aldehyde-based cross-linking agents, oxazoline-based cross-linking agents, metal alkoxide-based cross-linking agents, metal chelate-based cross-linking agents, metal salt-based cross-linking agents, and ammonium salt-based cross-linking agents. Each of these may be used alone, or two or more of them may be used in combination. Among these, isocyanate-based cross-linking agents are preferred. In this case, the (meth)acrylic acid ester polymer preferably contains at least one of carboxy group- or hydroxyl group-containing monomers as a monomer unit constituting the polymer. The pressure-sensitive adhesive obtained by combining with the isocyanate-based cross-linking agent has a significantly increased interfacial strength with the glass cloth layer. As a result, it is possible to produce a tape (cellophane tape-like wound product) that can be directly wound without using a release liner, which is advantageous in workability and self-back peelability.

The isocyanate-based cross-linking agent contains at least a polyisocyanate compound. Examples of polyisocyanate compounds include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate and xylylene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate; alicyclic polyisocyanates such as isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate; and their biuret, isocyanurate, and adducts which are reaction products with low-molecular-weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil. Each of these may be used alone, or two or more of them may be used in combination. Among these, from the viewpoint of reactivity with hydroxyl groups, trimethylolpropane-modified aromatic polyisocyanate is preferable, trimethylolpropane-modified tolylene diisocyanate and trimethylolpropane-modified xylylene diisocyanate are more preferable, trimethylolpropane-modified tri Diisocyanates are more preferred.

The content of the isocyanate-based cross-linking agent in the pressure-sensitive adhesive composition is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, relative to 100 parts by mass of the (meth)acrylic acid ester polymer. . Moreover, the upper limit of the content is preferably 10 parts by mass or less, and is adjusted in view of adhesive strength. By using an isocyanate-based cross-linking agent, adhesion to the glass cloth layer is improved, and problems such as adhesive scum and peeling from the support during processing can be reduced.

(Additives, etc.)
Various additives commonly used for acrylic pressure-sensitive adhesives can be added to the pressure-sensitive adhesive composition as long as they do not impair the object of the present invention. Examples of various additives include tackifiers, antioxidants, softeners, fillers, flame retardants and the like. A polymerization solvent and a diluting solvent, which will be described later, are not included in the additives constituting the adhesive composition. The flame retardant is preferably an aluminum phosphate flame retardant.

[Method for producing insulating adhesive tape]
Although the method for producing the insulating adhesive tape according to the present embodiment is not particularly limited, for example, when producing the insulating adhesive tape 1 as shown in FIG. is applied and cured to obtain an adhesive layer, and the adhesive layer is laminated on a glass cloth, so that the adhesive layer has an adhesive non-impregnated layer 13a that is not impregnated with the glass cloth and an adhesive impregnated layer 13b that is impregnated. 13 and the glass cloth layer 11 to produce a laminate a.
Subsequently, an insulating composition is applied to the surface of the laminate a opposite to the surface on which the adhesive layer 13 is provided through the glass cloth layer 11, dried, and cured to obtain a composition as shown in FIG. 1 (2). An insulating layer 12 having an insulating non-impregnated layer 12a that is not impregnated with the glass cloth layer 11 and an insulating impregnated layer 12b that is impregnated, and an adhesive layer 13 that has an adhesive impregnated layer 13b that is similarly impregnated with the glass cloth layer 11. and a glass cloth layer 11 between the insulating layer 12 and the adhesive layer 13 can be produced on a release film. From the viewpoint of obtaining a void-free insulating pressure-sensitive adhesive tape, it is desirable to adjust the viscosity of the insulating composition, apply the insulating composition directly to the glass cloth to impregnate it, and then dry it.
The above-mentioned tape may be wrapped around a cylindrical core material together with a release film to form a roll. It is also possible to form a roll by laminating while winding.

First, the insulating composition is applied on the release film, dried, laminated with a glass cloth, and then cured to form an insulating layer 12 having an insulating non-impregnated layer 12a and an insulating impregnated layer 12b and a glass cloth. After obtaining the laminate b with the layer 11, the adhesive composition is applied to a glass cloth, dried and cured to produce an insulating adhesive tape having a release film on the insulating layer 12 side. The above-mentioned tape can also be formed into a roll form by peeling the release film from the insulating layer 12 as necessary and winding and laminating the tape around the core material so that the adhesive layer 13 and the insulating layer 12 are in contact with each other.

In addition, from the viewpoint of improving adhesion with the insulating composition or adhesive composition and reducing voids during drying, the glass cloth should be subjected to surface treatment such as primer treatment, corona treatment, and plasma treatment before use. You may

The coating liquid for the insulating layer and the adhesive layer may be applied by a conventional method, such as bar coating, knife coating, Meyer bar method, roll coating, blade coating, die coating, gravure coating, and dip coating. etc.

The drying and curing conditions for the insulating composition are as follows: if the insulating composition is mainly composed of urethane acrylate, the insulating composition is dried at 80 to 150° C. by removing the solvent; It is preferred to cure in cm2. If it is an insulating composition mainly composed of polyimide and polyamide, it is preferable to dry it by removing the solvent at a temperature of 100 to 200 ° C. for 2 to 5 minutes and to cure it with a cross-linking agent. It is more preferable to perform aging in an environment of about 50° C. for about 1 hour to 5 days.

Regarding the drying and curing conditions of the adhesive composition, if it is a silicone-based adhesive, regardless of whether it is a peroxide-curing type or an addition-curing type, it is preferable to perform drying and curing by removing the solvent with hot air at 120 to 200°C for 5 minutes. Further, it is more preferable to perform aging in an environment of room temperature to 50° C. for 1 hour to 5 days. For acrylic pressure-sensitive adhesives, it is preferable to proceed with drying and curing by removing the solvent with hot air of 80°C to 150°C for 1 to 5 minutes, and then aging in an environment of room temperature to 50°C for about 1 hour to 5 days. is more preferable.

Films used as release films include polyester films made of polyester such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate, polyolefin films made of polyolefin such as polyethylene, polypropylene and polymethylpentene, polycarbonate films and polyvinyl acetate. Either a plastic film such as a film, a paper film such as pulp, or a laminate composed of two or more material layers of these can be mentioned, and the above film can be treated with a release agent. .

(Other layers)
In the case of a product form in which the insulating adhesive tape 1 shown in FIG. 1 is wound around a core material, the adhesive layer 13 and the insulating layer 12 as the surface layer are in direct contact with each other. Therefore, if necessary, a peeling agent may be applied to the surface of the insulating layer 12 to form a peeling layer so that the insulating layer 12 and the adhesive layer 13 can be peeled cleanly at the interface.

Materials imparting release agent properties used as raw materials for the release layer include silicone-based release agents, and long-chain alkyl pendant polymers in which alkyl groups having 16 to 24 carbon atoms are arranged in a pendant state via an ester group or an ether group. release agents, fluorine-based release agents, and the like.

<Other embodiments>

From the standpoint of cutting and punching the insulating adhesive tape in the present invention, and improving handleability such as toughness of the tape when sticking it to an object, it is also preferable to form an insulating adhesive tape having a thermoplastic resin layer.
The thermoplastic resin layer is positioned between the glass cloth layer and the insulating layer shown in FIG. 4 (embodiment 2), and positioned between the glass cloth layer and the adhesive layer shown in FIG. 5 (embodiment 3) is preferred.
In order to improve the bonding strength between the thermoplastic resin layer and the glass cloth layer in Embodiment 2, an adhesive layer 15 may be formed between the glass cloth layer and the thermoplastic resin layer as shown in FIG. Embodiment 4).
In Embodiment 3, in order to improve the bonding strength between the thermoplastic resin layer and the glass cloth layer, an adhesive layer 15 may be formed between the glass cloth layer and the thermoplastic resin layer as shown in FIG. 5).
In Embodiments 2 and 3, for example, a thermoplastic resin film is heated to a semi-molten state, and laminated and adhered to the glass cloth layer 11 to form a laminate of the glass cloth layer 11 and the thermoplastic resin layer 14. Later, it can be formed by laminating the insulating layer 12 and the adhesive layer 13 .
In Embodiments 4 and 5, for example, the adhesive layer 15 is formed on the thermoplastic resin layer 14, and the glass cloth layer 11 is laminated to form a glass cloth layer 11/adhesive layer 15/thermoplastic resin layer 11. It can be formed by laminating the insulating layer 12 and the adhesive layer 13 after forming the laminated body of the resin layer 14 .
It is to be noted that a form in which the pressure-sensitive adhesive layer 15 in the fifth embodiment is replaced by the pressure-sensitive adhesive layer 13 is also preferable.

The thickness of the thermoplastic resin layer 14 in Embodiments 2 to 5 is preferably 5 to 50 μm, more preferably 10 to 30 μm because it can be formed without affecting tracking resistance. The thickness of the adhesive layer 15 is sufficient as long as the thermoplastic resin layer can be bonded to other layers, and is preferably 1 to 15 μm within a range that does not affect the tracking resistance.

The thermoplastic resin film in the thermoplastic resin layer 14 may be any thermoplastic resin that can be produced in the form of a film, and known resins can be used. For example, polyethylene resin, polypropylene resin, polybutadiene resin, cyclic olefin resin, polymethylpentene resin, polystyrene resin, ethylene vinyl acetate copolymer, ethylene vinyl alcohol copolymer resin, ethylene acrylic acid ester copolymer, acrylonitrile/styrene resin, acrylonitrile/ Chlorinated polystyrene/styrene copolymer resin, acrylonitrile/acrylic rubber/styrene copolymer resin, acrylonitrile/butadiene/styrene copolymer resin, silicone resin, acetate resin, cellulose acetate resin, methacrylic resin, acrylic resin, vinyl chloride resin, chlorination Polyethylene resin, fluorinated polyethylene resin, polyvinylidene fluoride resin, nylon resin, polyacetal resin, polyester resin, polyethylene teretalate resin, polyethylene naphthalate resin, polybutylene teretalate resin, polycarbonate resin, modified polyphenylene ether resin, thermoplastic polyurethane elastomer , polyphenylene sulfide resin, polyetheretherketone resin, liquid crystal polymer, polytetrafluoroethylene resin, polyfluoroalkoxy resin, polyetherimide resin, polysulfone resin, polyketone resin, thermoplastic polyimide resin, polyamideimide resin, polyarylate resin, polysulfone Resins, polyether sulfone resins, biodegradable resins, and biomass resins can be mentioned, and they refer to film-formed resins.
In particular, a thermoplastic resin film obtained by filming polyethylene teretalate resin, which has high smoothness and is inexpensive, can be preferably used.

The adhesive used for the adhesive layer 15 may be any adhesive that can bond the thermoplastic resin layer 14 to another layer, and known adhesives such as acrylic resins, polyester resins, epoxy resins, urethane resins, etc. can be used. , a pressure-sensitive adhesive obtained by curing a silicone resin or the like. Commercially available products include polyester-based adhesive TM-K76 (curing agent CAT-RT85) manufactured by Toyo-Morton Co., Ltd. The composition of the adhesive layer 15 may be the same as or different from that of the adhesive layer 13 .

The insulating layer 12 and adhesive layer 13 in Embodiments 2 to 5 may be made of the same materials as those described with reference to FIG.

The insulating pressure-sensitive adhesive tape of the present invention may further contain a layer for imparting functions (characteristics) depending on the application within a range that does not hinder the object of the present invention. For example, a heat dissipation layer, a water vapor barrier layer, an electromagnetic wave absorption layer, a printed or colored design layer, and a polarizing layer may be provided as necessary.
However, even in this case, the glass cloth must be impregnated with the cured insulating composition or the cured pressure-sensitive adhesive composition.
Further, on the surface layer of the insulating layer 12, a protective layer or the like may be formed to protect the surface of the insulating layer 12, for example, as long as the object of the present invention is not hindered.

The present disclosure will be described below based on examples. In addition, the present disclosure is not limited to the following examples, and the following examples can be modified and changed based on the spirit of the present disclosure, and they are excluded from the scope of the present disclosure. is not. In the examples, "part" means "mass part" and "%" means "% by mass". The compounding amounts in the table are parts by mass.

[Raw materials for insulating composition]

<Acrylic material>
・(a-1) Urethane acrylate oligomer Mw: 2100 trifunctional EO chain-containing ・(a-2) Urethane acrylate oligomer Mw: 2000 trifunctional ・(a-3) Urethane acrylate oligomer Mw: 1000 pentafunctional ・(a-4 ) Urethane acrylate oligomer Mw: 300 bifunctional (a-5) Urethane acrylate oligomer Mw: 14000 bifunctional (a-6) Urethane acrylate oligomer Mw: 18000 bifunctional

<Photoinitiator>
・Oligo {2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone

<Polyimide resin>
Cyclohexanone (773.5 g) was added to a four-necked flask equipped with a stirrer, a reflux condenser equipped with a Dean-Stark apparatus, a nitrogen inlet tube and a thermometer while introducing nitrogen gas. Subsequently, 534.3 g (1.00 mol) of DDA shown in Table 1 as a diamine was added with stirring. Further, 117.58 g (0.524 mol) of TCA and 157.6 g (0.524 mol) of TDA shown in Table 1 as tetracarboxylic dianhydrides were added and stirred at room temperature for 30 minutes. After heating this to 100° C. and stirring for 3 hours, the oil bath was removed and the temperature was returned to room temperature to obtain a varnish-like polyimide precursor. Then, using a Dean-Stark apparatus, while removing distilled water out of the system, the mixture was heated at 170° C. for 10 hours for imidization to obtain a polyimide resin solution. Cyclohexane was added to the resulting polyimide resin solution to adjust the non-volatile content to 50%.

<Polyamide resin>
A polyamide resin solution was obtained in the same manner as for the polyimide resin, except that the monomers listed in Table 1 were used.

<Evaluation of polyimide resin and polyamide resin>
Table 1 shows the results of measuring the weight average molecular weight (Mw), aromatic ring concentration, and functional group concentration depending on the type of terminal functional group of the polyimide resin and polyamide resin obtained in each synthesis example by the measurement method shown below.

[Weight average molecular weight (Mw)]
The weight average molecular weight (Mw) was measured using GPC (gel permeation chromatography) "GPC-101" manufactured by Showa Denko K.K. GPC is liquid chromatography for separating and quantifying a substance dissolved in a solvent (THF: tetrahydrofuran) based on the difference in molecular size. As the column, two "KF-805L" (manufactured by Showa Denko Co., Ltd.: GPC column: 8 mm ID×300 mm size) connected in series were used. The measurement was performed under the conditions of a sample concentration of 1% by mass, a flow rate of 1.0 mL/min, a pressure of 3.8 MPa, and a column temperature of 40°C. The weight average molecular weight (Mw) was determined in terms of polystyrene. For data analysis, a calibration curve, molecular weight, and peak area were calculated using manufacturer's built-in software to determine the weight average molecular weight (Mw).

[Aromatic ring concentration]
The aromatic ring concentration of the polyimide resin and the polyamide resin was determined by the above formula (1).

[Functional group concentration (functional group value)]
(acid value)
About 1 g of a sample was accurately weighed into a common-stoppered Erlenmeyer flask and dissolved by adding 100 mL of cyclohexanone solvent. A phenolphthalein test solution was added to this as an indicator and held for 30 seconds. After that, the solution was titrated with a 0.1N alcoholic potassium hydroxide solution until it turned pink. The acid value was determined by the formula (2) (unit: mgKOH/g).
[Number 2]
Acid value (mgKOH/g) = (5.611 x a x F)/S (2)
S, a and F in the formula (2) represent the following.
・S: Amount of sample collected (g)
・a: Consumption of 0.1N alcoholic potassium hydroxide solution (mL)
• F: titer of 0.1 N alcoholic potassium hydroxide solution.

(Acid anhydride value)
About 1 g of a sample was accurately weighed into a common-stoppered Erlenmeyer flask and dissolved by adding 100 mL of 1,4-dioxane solvent. 10 mL of a mixed solution of octylamine, 1,4-dioxane, and water (mass mixing ratio is 1.49/800/80), which is larger than the amount of acid anhydride groups in the sample, is added and stirred for 15 minutes, and the acid anhydride is reacted with substances. Thereafter, excess octylamine was titrated with a mixed solution of 0.02M perchloric acid and 1,4-dioxane. In addition, 10 mL of a mixed solution of octylamine, 1,4-dioxane, and water (mass mixing ratio: 1.49/800/80) to which no sample was added was also measured as a blank. The acid anhydride value was determined by the formula (3) (unit: mgKOH/g)
[Number 3]
Acid anhydride value (mgKOH/g) = 0.02 x (BS) x F x 56.11/W (3)
B, S, W and F in Equation (3) represent the following.
・ B: Blank titration volume (mL)
・ S: Titration volume of sample (mL)
・ W: Sample solid amount (g)
• F: 0.02 mol/L perchloric acid titer.

<Production of insulating composition Z>
[Insulating composition Z-1]
An insulating composition Z-1 was obtained by blending 100 g of a urethane acrylate oligomer (a-1) with 5.0 g of a photopolymerization initiator and 100 g of MEK:IPA (isopropanol)=1:9 as a diluting solvent. .

[Insulating Composition Z-2]
An insulating composition Z-2 was obtained by blending 100 g of a urethane acrylate oligomer (a-2) with 5.0 g of a photopolymerization initiator and 100 g of MEK:IPA (isopropanol)=1:9 as a diluting solvent. .

[Insulating Composition Z-3]
An insulating composition Z-3 was obtained by blending 100 g of a urethane acrylate oligomer (a-3) with 5.0 g of a photopolymerization initiator and 100 g of MEK:IPA (isopropanol)=1:9 as a diluting solvent. .

[Insulating Composition Z-4]
An insulating composition Z-4 was obtained by blending 100 g of a urethane acrylate oligomer (a-4) with 5.0 g of a photopolymerization initiator and 100 g of MEK:IPA (isopropanol)=1:9 as a diluting solvent. .

[Insulating Composition Z-5]
An insulating composition Z-5 was obtained by blending 100 g of a urethane acrylate oligomer (a-5) with 5.0 g of a photopolymerization initiator and 100 g of MEK:IPA (isopropanol)=1:9 as a diluting solvent. .

[Insulating Composition Z-6]
An insulating composition Z-6 was obtained by blending 100 g of a urethane acrylate oligomer (a-6) with 5.0 g of a photopolymerization initiator and 100 g of MEK:IPA (isopropanol)=1:9 as a diluting solvent. .

[Insulating composition Z-7]
To 167.8 g of the polyimide resin solution described above, Tetrad C (epoxy compound (1,3-bis (N, N-diglycidylaminoethyl) cyclohexane, manufactured by Mitsubishi Gas Chemical Co., Ltd.)) 1.67 g as a cross-linking agent, a catalyst 0.43 g of DBU (1,8-diazabicyclo[5,4,0]-undecene-7) as a solvent and 30.1 g of toluene as a solvent were mixed and stirred with a mixer to obtain an insulating composition Z-7. .

[Insulating Composition Z-8]
To 167.8 g of the polyamide resin solution described above, 1.67 g of Tetrad C as a cross-linking agent, 0.43 g of DBU as a catalyst, and 30.1 g of toluene as a solvent are mixed and stirred with a mixer to obtain an insulating composition Z-8. Obtained.

[Raw materials for adhesive composition]
<Synthesis of acrylic adhesive>
500 g of ethyl acetate was heated in a water bath while introducing nitrogen gas into a four-necked flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube and a thermometer. Subsequently, 240 g of BA (n-butyl acrylate), 240 g of 2-EHA (2-ethylhexyl acrylate), 20 g of AA (acrylic acid) and 0.5 g of AIBN (azobisisobutyronitrile) as an initiator were added. The mixture was dropped into ethyl acetate and reacted for 8 hours while maintaining reflux. After the reaction, 110 g of ethyl acetate was added to obtain an acrylic adhesive having a non-volatile content of 45% and a weight average molecular weight (Mw) of 650,000.

In addition, the weight average molecular weight (Mw) was measured under the following conditions. The weight average molecular weight (Mw) was determined by a calibration curve method using polystyrene with a known weight average molecular weight as a standard substance.
・ Apparatus name: LC-GPC system “Prominence” manufactured by Shimadzu Corporation
・Column: TSKgel (registered trademark) α-M manufactured by Tosoh Corporation, two columns connected in series ・Mobile phase solvent: tetrahydrofuran ・Flow rate: 1.0 mL/min ・Column temperature: 40°C.

<Production of adhesive composition N>
[Adhesive composition N-1]
For 100 g of the acrylic pressure-sensitive adhesive obtained above, 0.5 g of an isocyanate curing agent (Duranate TLA-100 manufactured by Asahi Kasei Corporation, NCO wt%: 23.3%) as a cross-linking agent is blended and stirred to achieve stickiness. A composition N-1 was obtained.

[Adhesive composition N-2]
Silicone adhesive: 0.5 g of benzoyl oxide and 50 g of MEK were added to 100 g of KR-130 (manufactured by Shin-Etsu Chemical Co., Ltd.) and mixed with stirring to obtain an adhesive composition N-2.

<Properties of Glass Cloth>
Table 2 shows the properties of the glass cloths G-1 to G-6 used as raw materials for the glass cloth layers used in the examples.

<Other materials>
Release film: SP PET-01-BU, thickness 50 μm, single-sided silicone release treatment, PET film separator manufactured by Mitsui Chemicals Tocello Co., Ltd.

[Resin film]
· PI: Aromatic polyimide film (manufactured by DuPont-Toray Co., Ltd., product name: Kapton 100H (Kapton)).
・ PEN: polyethylene naphthalate film (manufactured by Toyobo Co., Ltd., product name: Teonex Q51-25)
・ GSF: Resin film containing glass fiber filler; After mixing 100 g of insulating composition Z-7 and 10 g of glass fiber filler (milled fiber HP3610, glass filament diameter 10 μm), it was dried on a release film to a thickness of 30 μm. It was coated so as to be even, dried at 150° C., and the release film was removed.

<Manufacture of insulating adhesive tape>
[Example 1]
Adhesive composition N-1 was dried with a doctor blade on the release-treated surface of a 300 mm square release film, coated to a thickness of 30 μm, and dried in an oven at 100° C. for 5 minutes to obtain an adhesive layer. The adhesive layer and the glass cloth G-1 are laminated together with a laminator at a roll pressure of 0.2 MPa, a speed of 100 mm/min, and a temperature of 23° C. to form an adhesive layer 13/glass on the release film. A laminate a having a cloth layer 11 (layer thickness of 50 μm with an adhesive impregnated layer of 5 μm and an adhesive non-impregnated layer of 25 μm) was obtained.

Next, the insulating composition Z-1 was applied with a doctor blade to the surface of the glass cloth layer 11 opposite to the adhesive layer 13 of the laminate a so that the total thickness of the insulating adhesive tape was 60 μm. After drying with hot air for 1 minute, the insulating adhesive tape of Example 1 was obtained by curing with a high-pressure mercury lamp at an irradiation intensity of 80 mW/cm 2 and an integrated light quantity of 500 mJ/cm 2 .
A portion of the insulating adhesive tape ZN-1 was frozen with liquid nitrogen, cut with a razor to obtain a tape section, and the thickness of each layer was measured by SEM observation of the section at 500 magnification.

[Examples 2 to 6, Examples 9 to 23]
Insulating adhesive tapes of Examples 2 to 6 and Examples 9 to 23 were obtained in the same manner as in Example 1, except that the raw materials for the insulating layer were changed to those shown in Tables 3 to 6.

[Examples 7-8]
Same as Example 1, except that the raw material and thickness of each layer were changed to those shown in Tables 3 to 6, the drying temperature of the insulating composition was 150 ° C., and the ultraviolet irradiation by the mercury lamp was not performed. Insulating adhesive tapes of Examples 7 and 8 were obtained by the method of.

[Comparative Example 1]
A laminate a obtained in the manufacturing process of Example 1 was designated as Comparative Example 1.

[Comparative Example 2]
After forming the adhesive layer 13, an insulating adhesive tape of Comparative Example 2 was obtained in the same manner as in Example 1 except that the insulating layer was applied directly to the surface of the adhesive layer 13 without laminating the glass cloth layer. .

[Comparative Examples 3-5]
The same procedure as in Example 1 was performed, except that after bonding the resin film PI, PEN, or GSF to the adhesive layer instead of the glass cloth, an insulating layer was applied to the resin film surface opposite to the surface in contact with the adhesive layer. According to the method, insulating adhesive tapes of Comparative Examples 3 and 4 were obtained.

Various thicknesses were obtained by taking out a section by the above-described ion milling method, measuring by SEM observation at a magnification of 500, and averaging five points.

<Evaluation of insulating adhesive tape>
Various performance evaluation methods and evaluation criteria for the tapes obtained in Examples and Comparative Examples are shown below. Tables 3 to 6 show evaluation results based on the following evaluation criteria.

[Tracking resistance]
Methods for measuring the anti-tracking performance of insulating materials include the Proof Tracking Index based on IEC60112, JIS C2134, ASTM D3638 or UL746A. The upper limit of the PTI test voltage is specified as 600V. As a technique for measuring tracking performance using a high voltage exceeding 600 V, there is an Inclined-Plane Tracking (IPT) test based on IEC60587, JIS C2136 or ASTM D2303. The lower limit of the IPT test voltage is specified as 1 kV (1000 V). Since the presence or absence of the reverse trend phenomenon cannot be confirmed in the CTI evaluation performed from the test start voltage of 300 volts after the revision of UL746A, the test is performed in this specification with the upper limit of the test voltage set to 1000 V in accordance with IEC60112. was measured at the specified voltage.
The designated voltages were 300V, 600V and 1000V.
In this specification, when there is a flash, a criterion is set separately for the presence of the flash, and it is evaluated as the presence of the reverse trend phenomenon.
The presence or absence of the PTI and reverse trend phenomenon of the insulating adhesive tape was evaluated based on the following evaluation criteria.
(Evaluation criteria)
S: Cleared the test at all specified voltages.
A: Cleared the test at specified voltages of 600V and 300V, but did not reach 1000V.
B: Cleared the test at the specified voltages of 600V and 300V, but did not reach 1000V. There is a flash at the specified 300 V (with reverse trend phenomenon).
C: Cleared the test at the specified voltage of 600 V, but did not reach 300 V and 1000 V (with reverse trend phenomenon).

[Heat-resistant]
Based on JISC4003:2010, a thermal evaluation test was performed on the insulating adhesive tape from which the release film was removed, the heat resistance temperature was measured, and the heat resistance of the insulating adhesive tape was evaluated based on the following evaluation criteria.
(Evaluation criteria)
S: Heat resistant temperature is 200° C. or higher (heat resistant class: N, R).
A: The heat resistance temperature is 180° C. or more and less than 200° C. (heat resistance class: H).
B: The heat resistance temperature is 155° C. or more and less than 180° C. (heat resistance class: F).
C: The heat resistant temperature is less than 155°C (heat resistant class: B or lower).

[Insulation]
Three 25 mm square insulating adhesive tapes were prepared, and according to JIS C 2110, the dielectric breakdown voltage was measured once for each sheet using an AC withstand voltage tester (manufactured by Keisoku Giken Co., Ltd., 7470). Under the environment of 23 ° C. and 50% RH, measurement was performed at a frequency of 60 Hz and a boost rate of 0.1 kV / sec, and the average value of the absolute values obtained by measuring a total of three times for each tape was taken as the dielectric breakdown voltage (kV). bottom.
In the above measurement, the adhesive layer from which the release film was removed was attached to the lower electrode serving as the base of the electrode, and one sheet was sandwiched so that the upper electrode was in contact with the insulating layer.
S is good, A can be used for general purposes, B can be used depending on the usage environment, and C is not practical as an insulating adhesive tape.
S: 5 kV or more A: 4 kV or more and less than 5 kV B: 3 kV or more and less than 4 kV C: less than 3 kV

[Wrapability]
Each insulating adhesive tape is cut into strips of 2 cm width and 20 cm length, and the insulating adhesive tape is wound perpendicularly to the length direction on a circular steel bar of 5 cm length and 2 mm outer diameter. For winding, peel off the release film and start winding so that the exposed adhesive layer adheres to the steel rod. . The steel rod wound with the tape was fixed to a jig so as to stand upright, and allowed to stand in an environment of 23° C. and 50% RH for 1 hour for 1 day to stabilize the adhesion of the adhesive tape and prepare 4 test samples.
Each test sample was exposed to the following four environmental conditions, and evaluated according to the following evaluation criteria based on the presence or absence of peeling of the wound tape end after that. Peeling at the edge was defined as peeling when 1 mm or more was peeled off from the edge of the tape with which the adhesive surface was in contact before the test.

Condition 1: Leave at 100°C for 1 hour Condition 2: Leave at 200°C for 1 hour Condition 3: Leave at 100°C for 30 minutes, then repeat at -10°C for 30 minutes 5 times Condition 4: 200°C After standing in the environment for 30 minutes, repeat 30 minutes in the -10°C environment 5 times

(Evaluation criteria)
S: No peeling of the edge is observed under all conditions. Best A: No peeling under Conditions 1, 2 and 3, peeling observed under Condition 4. Good B: No peeling under Conditions 1 and 3, but peeling under Conditions 2 and 4. Can be used for a long period of time in a general-purpose environment. Can be used in a general-purpose environment for a short period of time D: No peeling under Condition 1, but peeling under Conditions 2, 3 and 4. Or the shape cannot be maintained. Limited use environment

In Examples 1 to 23, the reverse trend phenomenon was overcome by combining the specific glass cloth layer, the specific insulating layer, and the specific adhesive layer, and high levels of tracking resistance, insulation, winding workability, and heat resistance were realized. . In addition, by being within the preferred range, further performance improvements can be seen, and while some insulating adhesive tapes have high workability, PTI: 1000V, which is unparalleled, has both tracking resistance and high heat resistance. rice field.

On the other hand, in Comparative Example 1, since there is no insulating layer, the tracking resistance and insulating properties are insufficient. In 4, since the glass cloth layer is not used, the generation of tracking resistance including the reverse trend phenomenon and the heat resistance are insufficient, and in Comparative Example 5, in which a glass fiber filler is used instead of the glass cloth, the heat resistance and winding workability are insufficient. Met.

1 Insulating adhesive tape 11 Glass cloth layer 12 Insulating layer 12a Insulating non-impregnated layer 12b Insulating impregnated layer 13 Adhesive layer 13a Adhesive non-impregnated layer 13b Adhesive impregnated layer 14 Thermoplastic resin layer 15 Adhesive layer

Claims (6)

An insulating adhesive tape having an insulating layer, an adhesive layer, and a glass cloth layer,
The glass cloth layer is located between the insulating layer and the adhesive layer,
The glass cloth layer is impregnated with at least one of the insulating layer and the adhesive layer,
The glass cloth layer has a thickness of 10 μm to 50 μm and a weaving density of 10 lines/10 mm to 50 lines/10 mm,
The diameter of the glass thread constituting the glass cloth layer is 100 μm to 500 μm,
The insulating layer is a cured product by active energy rays,
The insulating adhesive tape having a thickness of 30 μm to 200 μm . 2. The insulating adhesive tape according to claim 1 , wherein the insulating layer is a layer obtained by curing an acrylic material having a weight average molecular weight of 300 to 15,000. An insulating adhesive tape having an insulating layer, an adhesive layer, and a glass cloth layer,
The glass cloth layer is located between the insulating layer and the adhesive layer,
The glass cloth layer is impregnated with at least one of the insulating layer and the adhesive layer,
The glass cloth layer has a thickness of 10 μm to 50 μm and a weaving density of 10 lines/10 mm to 50 lines/10 mm,
The diameter of the glass thread constituting the glass cloth layer is 100 μm to 500 μm,
The insulating layer is formed of a resin mainly composed of polyimide or polyamide having an aromatic ring concentration of 30% by mass or less,
The insulating adhesive tape having a thickness of 30 μm to 200 μm . Furthermore, an insulating adhesive tape having a thermoplastic resin layer,
2. The insulating adhesive tape according to claim 1, wherein the thermoplastic resin layer is positioned between the glass cloth layer and the insulating layer or between the glass cloth layer and the adhesive layer. 5. The insulating pressure-sensitive adhesive tape according to any one of claims 1 to 4 , which has a guaranteed tracking index (PTI) of 300V and 600V measured according to tests based on IEC60112, JIS C2134 or ASTM D3638. 5. The insulating pressure-sensitive adhesive tape according to any one of claims 1 to 4 , which has a guaranteed tracking index (PTI) of 300V, 600V and 1000V as measured according to tests based on IEC60112, JIS C2134 or ASTM D3638.

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