JP4611705B2 - Film base and adhesive tape - Google Patents

Description

The present invention relates to a film substrate and an adhesive tape using the film substrate. Units such as “parts” indicating the composition of the present invention are displayed on a mass basis unless otherwise specified.

In addition to vehicles such as automobiles, trains, etc., in various adhesive tape fields such as insulating tapes used in electrical equipment such as aircraft, ships, houses, factories, etc., it has moderate flexibility and extensibility, flame resistance, machinery A film made from a resin composition containing a vinyl halide resin such as polyvinyl chloride because it is excellent in terms of mechanical strength, heat distortion resistance, electrical insulation and moldability, and is relatively inexpensive. Have been used. Since such a halogenated vinyl resin film generates a toxic gas when incinerated, recently, a metal hydroxide (eg, magnesium hydroxide, aluminum hydroxide, etc.) having a low environmental impact on the polyolefin resin is used. A film using a non-halogen resin composition containing a large amount of an inorganic flame retardant composed of an inorganic metal compound as a raw material has begun to be used.

As an adhesive tape using a film made of such a non-halogen resin composition as a raw material, an adhesive tape characterized by using a composition containing an olefin polymer and an inorganic flame retardant as a film substrate is known. (For example, Patent Document 1).
JP 2001-192629 A

An object of the present invention is to provide a film base material having all properties of flexibility, hand cutting property, heat resistance and wear resistance in a balanced manner, and an adhesive tape using the film base material.

That is, the present invention is a film substrate containing 10 to 60 parts by mass of a styrene resin and 1 to 50 parts by mass of a maleimide copolymer with respect to 100 parts by mass of an aromatic vinyl elastomer. Furthermore, the aromatic vinyl elastomer is preferably a styrene-butadiene random copolymer, a styrene-butadiene block copolymer and / or a hydrogenated product thereof. Furthermore, it is preferable that the styrenic resin is polystyrene resin (GPPS) or rubber-reinforced polystyrene (HIPS). A maleimide copolymer is obtained by polymerizing 15 to 70% by mass of an aromatic vinyl monomer and 30 to 85% by mass of an unsaturated dicarboxylic imide derivative, and the aromatic vinyl monomer is styrene or unsaturated. It is preferable that the dicarboxylic imide derivative is N-phenylmaleimide. Furthermore, it is preferable that 1-200 mass parts of inorganic fillers are included in a film base material. Furthermore, the inorganic filler is preferably at least one compound selected from the group consisting of aluminum hydroxide, magnesium hydroxide, hydrotalcite, and magnesium carbonate. Moreover, it is preferable to crosslink by irradiating an electron beam to a film base material. On the other hand, this invention is the adhesive tape which formed the adhesive layer in the single side | surface of a film base material. Moreover, it is an adhesive tape for binding using an adhesive tape.

The pressure-sensitive adhesive tape using the film substrate of the present invention can provide a pressure-sensitive adhesive tape excellent in flexibility, hand cutting, heat resistance and wear resistance.

Examples of the aromatic vinyl-based elastomer that can be used for the film substrate include styrene-ethylene-butylene copolymer-styrene (SEBS), styrene-ethylene-propylene copolymer-styrene (SEPS), and styrene-butadiene-styrene ( SBA), ABA type block copolymers such as styrene-isoprene-styrene (SIS), random copolymers, and hydrogenation of these ABA type block copolymers and random copolymers , Styrene-butadiene copolymer, AB type block copolymer such as styrene-isoprene copolymer, random copolymer, and hydrogenation of these AB type block copolymer and random copolymer Use one or more of these elastomers as appropriate. It can be. Preferably, a styrene-butadiene random copolymer, a styrene-butadiene block copolymer, and / or a complete or partial hydrogenated product thereof is used. More preferably, a completely hydrogenated product of a styrene-butadiene random copolymer having a low elongation at break is preferred.

Further, from the viewpoint of heat resistance and weather resistance, the hydrogenation rate of the carbon-carbon double bond derived from butadiene in the styrene-butadiene random copolymer before hydrogenation is preferably 50 mol% or more, more preferably. It is 70 mol% or more. The carbon-carbon double bond content in the hydrogenated random copolymer can be measured by iodine value measurement, infrared spectrophotometer, nuclear magnetic resonance method or the like.

The blending amount of the styrene resin is 10 to 60 parts by mass, preferably 10 to 40 parts by mass with respect to 100 parts by mass of the aromatic vinyl elastomer. When the styrene-based resin is less than 10 parts by mass, the strength of the film substrate is low and the film is easily stretched. On the other hand, when the styrene resin exceeds 60 parts by mass, the workability of the film base material is lost, and the film base material becomes rigid and the pinhole resistance is lowered.

The styrene resin is not particularly limited, and a commonly used known resin can be used. Specifically, a polystyrene resin called GPPS or a rubber-reinforced polystyrene called HIPS is preferable, and a polystyrene resin that can easily adjust the film strength by controlling the molecular weight is preferable.

The blending amount of the maleimide copolymer is preferably 1 to 50 parts by mass with respect to 100 parts by mass of the aromatic vinyl elastomer. Preferably it is the range of 10-35 mass parts. When the maleimide copolymer is less than 1 part by mass, the thermal shrinkage of the film substrate is worsened. On the other hand, when it exceeds 50 mass parts of maleimide-type copolymers, there exists a problem that the workability of a film base material will worsen.

The weight average molecular weight of the maleimide copolymer is preferably 60,000 to 140,000, more preferably 80,000 to 120,000. When the weight average molecular weight of the maleimide copolymer is less than 60,000 or more than 140,000, the heat resistance is deteriorated and the fluidity of the resin during processing is deteriorated.

The maleimide copolymer is obtained by polymerizing 15 to 70% by mass of an aromatic vinyl monomer and 30 to 85% by mass of an unsaturated dicarboxylic imide derivative. More preferably, the aromatic vinyl monomer is 15 to 70% by mass, the unsaturated dicarboxylic imide derivative is 25 to 65% by mass, the unsaturated dicarboxylic acid anhydride is 0.1 to 25% by mass, and a vinyl monomer copolymerizable therewith. It is formed by polymerizing 0.1 to 40% by mass of a monomer. If the aromatic vinyl monomer content is less than 15% by mass or the unsaturated dicarboxylic acid imide derivative exceeds 85% by mass, the difference in melt viscosity from the aromatic vinyl-based elastomer increases, resulting in poor melt mixing and moldability of the film substrate. Decreases. On the other hand, if the aromatic vinyl monomer exceeds 70% by mass or the unsaturated dicarboxylic imide derivative is less than 30% by mass, the effect of imparting heat resistance as a film substrate is deteriorated.

Examples of the aromatic vinyl monomer of the maleimide copolymer include styrenes such as styrene, α-methylstyrene, vinyltoluene, ethylstyrene, t-butylstyrene, and substituted products thereof. Preferably, it is styrene that facilitates numerical control of the molecular weight increased by the reaction.

Examples of the unsaturated dicarboxylic imide derivative of the maleimide copolymer include maleimide monomers such as maleimide, N-methylmaleimide, N-ethylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, and N-naphthylmaleimide. N-phenylmaleimide having high heat resistance is preferable.

Examples of the unsaturated dicarboxylic acid anhydride of the maleimide copolymer include anhydrides such as maleic acid, itaconic acid, citraconic acid, and aconitic acid. Preferably, it is maleic anhydride that facilitates numerical control of the molecular weight that increases by the reaction.

Vinyl monomers copolymerizable with unsaturated dicarboxylic acid anhydrides include, for example, vinyl cyanides such as acrylonitrile and methacrylonitrile, acrylic esters such as methyl acrylate, ethyl acrylate and butyl acrylate, methyl methacrylate and ethyl Methacrylic acid esters such as methacrylate, and vinyl carboxylic acids such as acrylic acid and methacrylic acid.

The reason for blending inorganic fillers is to improve the hand cutting property of the film base material, while increasing the heat conduction during the molding process to increase the cooling effect of the film base material and to suppress the distortion generated in the film base material. Because. The average particle diameter of the inorganic filler is, for example, 20 μm or less, preferably 10 μm or less. When the average particle size is less than 0.5 μm, workability and hand cutting properties may be deteriorated. On the other hand, if the average particle diameter exceeds 10 μm, the tensile strength and breaking elongation of the film base material may be lowered, and the flexibility may be lowered and pinholes may be generated. The average particle diameter is an average particle diameter measured by a laser diffraction method.

Examples of inorganic fillers include aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, calcium hydroxide, potassium hydroxide, barium hydroxide, triphenyl phosphite, ammonium polyphosphate, polyphosphate amide, zirconium oxide and magnesium oxide. , Zinc oxide, titanium oxide, molybdenum oxide, guanidine phosphate, hydrotalcite, snakerite, zinc borate, anhydrous zinc borate, zinc metaborate, barium metaborate, antimony oxide, antimony trioxide, antimony pentoxide, red phosphorus, Talc, alumina, silica, boehmite, bentonite, sodium silicate, calcium silicate, calcium sulfate, calcium carbonate, and magnesium carbonate, and one or more compounds selected from these are used. In particular, the use of at least one selected from the group consisting of aluminum hydroxide, magnesium hydroxide, hydrotalcite, and magnesium carbonate is excellent in flame retardancy and is economically advantageous.

The compounding quantity of an inorganic filler is 1-200 mass parts with respect to 100 mass parts of aromatic vinyl-type elastomers, Preferably it is the range of 5-100 mass parts. When the inorganic filler is less than 1 part by mass, the flame retardancy of the film substrate may be inferior. On the other hand, when the inorganic filler exceeds 200 parts by mass, mechanical properties such as moldability and strength of the film substrate may be inferior.

When an inorganic filler is blended as a non-halogen flame retardant, the char (carbonized layer) can be formed and the flame retardancy of the film substrate can be improved.

A colorant, an antioxidant, an ultraviolet absorber, a lubricant, a stabilizer, and other additives can be blended with the film base as needed, as long as the effects of the present invention are not impaired.

The means for forming the film substrate is not particularly limited, and examples thereof include an extrusion method, a rolling method, and a laminating method.

The thickness in particular of a film base material is not restrict | limited, For example, it is 40-500 micrometers, Preferably it is 70-200 micrometers, More preferably, it is 80-160 micrometers. In addition, the film base material may have a single layer form, and may have a multiple layer form. For example, in order to cope with the operation of winding an adhesive tape around an electric wire having various forms, the winding workability may be reduced when the thickness of the film substrate is increased.

By irradiating the film base material with an electron beam and crosslinking, the film base material can be prevented from being deformed or contracted when placed under a high temperature, and the temperature dependency can be reduced. In this case, the irradiation amount of the electron beam is preferably in the range of 10 to 150 Mrad (mega rad). The range of 15 to 25 Mrad is preferable. If the irradiation amount is less than 10 Mrad, the temperature dependency is not improved. On the other hand, when the irradiation amount exceeds 150 Mrad, the film base material is deteriorated by the electron beam, which may cause a problem in workability in post-processing.

A cross-linking agent for promoting electron beam cross-linking may be added. Specific examples of the crosslinking agent include low molecular weight compounds and oligomers having at least two carbon-carbon double bonds in the molecule, such as acrylate compounds, urethane acrylate oligomers, and epoxy acrylate oligomers.

An adhesive layer may be formed on one side of the film substrate. As a pressure-sensitive adhesive for constituting the pressure-sensitive adhesive layer, a commonly used pressure-sensitive adhesive can be used as appropriate, and for example, a rubber-based pressure-sensitive adhesive or an acrylic pressure-sensitive adhesive can be used. Moreover, in order to make these adhesives have desirable performance, tackifiers, anti-aging agents, curing agents, and the like can be blended.

As the base polymer of the rubber adhesive, natural rubber, recycled rubber, silicone rubber, isoprene rubber, styrene butadiene rubber, polyisoprene, NBR, styrene-isoprene copolymer, styrene-isoprene-butadiene copolymer and the like are preferable.

A crosslinking agent, a softening agent, a filler, a flame retardant, and the like can be added to the rubber-based pressure-sensitive adhesive as necessary. Specific examples include isocyanate crosslinking agents as crosslinking agents, liquid rubber as softening agents, calcium carbonate as fillers, and inorganic flame retardants such as magnesium hydroxide and red phosphorus as flame retardants.

Examples of the acrylic pressure-sensitive adhesive include a homopolymer of (meth) acrylic acid ester or a copolymer with a copolymerizable monomer. (Meth) acrylic acid ester or copolymerizable monomer includes (meth) acrylic acid alkyl ester (for example, methyl ester, ethyl ester, butyl ester, 2-ethylhexyl ester, octyl ester, etc.), (meth) acrylic acid glycidyl ester , (Meth) acrylic acid, itaconic acid, maleic anhydride, (meth) acrylic acid amide, (meth) acrylic acid N-hydroxyamide, (meth) acrylic acid alkylaminoalkyl ester (for example, dimethylaminoethyl methacrylate, t- Butylaminoethyl methacrylate), vinyl acetate, styrene, acrylonitrile and the like. Of these, as the main monomer, an alkyl acrylate ester whose homopolymer (homopolymer) usually has a glass transition temperature of −50 ° C. or lower is preferred.

The tackifying resin agent can be selected in consideration of the softening point, compatibility with each component, and the like. Examples include terpene resins, rosin resins, hydrogenated rosin resins, coumarone / indene resins, styrene resins, aliphatic and alicyclic petroleum resins, terpene-phenol resins, xylene resins, and other aliphatic carbonizations. Examples thereof include hydrogen resins and aromatic hydrocarbon resins. The softening point of the tackifying resin is preferably 65 to 130 ° C, and moreover, an alicyclic saturated hydrocarbon resin of a petroleum resin having a softening point of 65 to 130 ° C, a polyterpene resin having a softening point of 80 to 130 ° C, and a softening point of 80 to 130. More preferred is a glycerin ester of hydrogenated rosin at 0 ° C. These can be used either alone or in combination.

The anti-aging agent is used to improve the rubber-based pressure-sensitive adhesive because it has an unsaturated double bond in the rubber molecule and is likely to deteriorate in the presence of oxygen or light.

Examples of the anti-aging agent include phenolic anti-aging agents, amine-based anti-aging agents, benzimidazole-based anti-aging agents, dithiocarbamate-based anti-aging agents, phosphorus-based anti-aging agents and the like alone or as a mixture. it can.

Examples of the curing agent for the acrylic pressure-sensitive adhesive include isocyanate-based, epoxy-based, and amine-based ones, and may be a mixture of these alone or a mixture thereof.

Specific examples of the isocyanate curing agent include polyvalent isocyanate compounds such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylene diisocyanate, and diphenylmethane. -4,4'-diisocyanate, diphenylmethane-2,4'-diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, Examples include lysine isocyanate.

The means for applying to the film substrate such as the pressure-sensitive adhesive, pressure-sensitive adhesive imparting agent and anti-aging agent constituting the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape is not particularly limited. For example, the pressure-sensitive adhesive, the pressure-sensitive adhesive imparting agent and There is a method in which a pressure-sensitive adhesive solution comprising an anti-aging agent or the like is applied to one side of the film substrate by a transfer method and dried. Although the thickness of an adhesive layer can be suitably selected in the range which does not impair adhesiveness or handleability, the thickness of an adhesive layer is 5-100 micrometers, for example, Preferably it is 10-50 micrometers. If it is thinner than this, the adhesive force and the unwinding force may decrease. On the other hand, if it is thicker than this, the coating performance may deteriorate.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

In Table 1, “back adhesive strength” was measured according to JIS C 2107. In an evaluation test chamber set to a temperature of 23 ± 2 ° C. and a humidity of 50 ± 5% RH, a test piece is pressure-bonded to a SUS test plate on which an adhesive tape to be tested is attached, and the pressure roller is moved at a speed of 300 mm / min. After reciprocating once, after leaving for 20 to 40 minutes, the value when the test piece was peeled off from the test plate at a speed of 300 mm / min was the back adhesive strength, and the average value of n = 3 or more was measured. .

In Table 1, “flexibility” is the tensile strength of 25% modulus measured in accordance with JIS C 2107. In an evaluation test chamber set at a temperature of 23 ± 2 ° C. and a humidity of 50 ± 5% RH, the pressure-sensitive adhesive tape to be tested showed an average value of measured values of n = 3 or more, and was evaluated according to the following criteria.
O The tensile strength of a modulus is 5.0-15.0 N / mm < ² >.
X Less than 5.0 N / mm ² , 15.0 N / mm ² or more.

In Table 1, “elongation” is the tensile elongation at break measured according to JIS C 2107. In an evaluation test chamber set at a temperature of 23 ± 2 ° C. and a humidity of 50 ± 5% RH, the pressure-sensitive adhesive tape to be tested showed an average value of measured values of n = 3 or more, and was evaluated according to the following criteria.
○ Tensile elongation at break is 100 to 400%.
X Less than 100%, 400% or more.

In Table 1, “hand cutting property” means that the adhesive tape formed to a length of 100 mm is cut by a human hand in the horizontal direction, and the cut surface of the cut surface of the adhesive tape is evaluated. evaluated.
○ The cut end is clean.
X The cut end extends and further cuts in the flow direction of the adhesive tape.

In Table 1, “thermal shrinkage” means an evaluation test chamber set at a temperature of 23 ± 2 ° C. and a humidity of 50 ± 5% RH after leaving a 100 mm long film at 100 ° C. for 10 minutes. The shrinkage rate of MD and TD after standing for 20 minutes or longer. An average value of measured values of n = 3 or more is shown and evaluated according to the following criteria.
○ Shrinkage is less than 10%.
X 10% or more.

In Table 1, “Abrasion resistance” means that a cotton cloth No. 3 is placed as a wear material on a film having a length of 100 mm and a width of 50 mm, a weight of 500 g is placed thereon, and a speed of 80 reciprocations per minute. The film was scratched and scraped after being rubbed with the wear material, and visually evaluated according to the following criteria.
○ No scratches or scratches.
× Scratched or shaved.

In Table 1, “workability” was evaluated based on the following criteria for ease of use when an adhesive tape was wound around an electric wire cable having a diameter of 1 mm.
○ The adhesive tape does not stretch or break during winding.
X Those with elongation or breakage.

In Table 1, “terminal peeling” means that an adhesive tape is wound around an electric wire cable in a half wrap shape, and the presence or absence of terminal peeling of the terminal portion at the time of cutting at the end of winding is visually evaluated according to the following criteria.
○ There is no terminal peeling.
× Something with terminal peeling.

In Table 1, “whitening” was performed by visually observing the presence or absence of whitening of the cut surface at the end of winding, by winding an adhesive tape around a wire cable in a half wrap shape.
○ No whitening.
× Things with whitening.

In Table 1, “flame retardancy” was measured according to JIS K 7201. An adhesive tape sample with a width of 20 mm and a length of 150 mm is fixed to a wire with a diameter of 0.8 mm, and stands upright, kept at the measured oxygen concentration for 30 seconds, ignited from the upper end of the sample, and after removing the ignition source, within 4 seconds This is the oxygen concentration (oxygen index) when digested. In Table 1, the minimum value of the measured values of n = 3 or more is shown and evaluated according to the following criteria.
○ The oxygen index is 18 or more.
X Less than 18.

(Example 1) The composition of the film base of the pressure-sensitive adhesive tape in this example was 100 parts by mass of a completely hydrogenated styrene-butadiene random copolymer (SOE SS9000 manufactured by Asahi Kasei Chemicals Corporation) 30 parts by mass of styrene resin (G-14L manufactured by Toyo Styrene Co., Ltd.), 30 parts by mass of maleimide copolymer (MS-NB: 46% by mass of aromatic vinyl monomer, unsaturated dicarboxylic acid manufactured by Denki Kagaku Kogyo Co., Ltd.) 52 parts by weight of imide derivative, 2% by weight of unsaturated dicarboxylic acid anhydride), 30 parts of magnesium hydroxide having an average particle size of 5.0 μm (Magsees N-1 manufactured by Kamishima Chemical Co., Ltd.), and other small amounts of stabilizers, lubricants, colorants Is contained. The back adhesive strength is 3.0 N / 10 mm. As a pressure-sensitive adhesive, it contains a rubber-based pressure-sensitive adhesive made of a mixture of natural rubber and SBR. This compounding agent is kneaded with a Banbury mixer, formed into a thickness of about 0.1 mm by calendering, and then a tape having a width of 25 mm. The adhesive tape of Example 1 was obtained.

In Example 1, all the characteristic values were evaluated as good, and an adhesive tape having the desired flexibility, hand cutting, heat resistance, wear resistance, and the like was obtained. The comparative examples described below are the same as the present examples unless otherwise specified.

Example 2 The composition was the same as in Example 1 except that the adhesive was changed from a rubber adhesive to an acrylic adhesive. All the characteristic values were evaluated as good, and the intended adhesive tape was obtained.

Example 3 100 parts by mass of a completely hydrogenated styrene-butadiene random copolymer was changed to 100 parts by mass of a completely hydrogenated styrene-butadiene block copolymer (SIBSTAR 103T manufactured by Kaneka Chemical Co., Ltd.). Was the same formulation as in Example 1. All the characteristic values were evaluated as good, and the intended adhesive tape was obtained.

Example 4 The composition was the same as in Example 3 except that the adhesive was changed from a rubber adhesive to an acrylic adhesive. All the characteristic values were evaluated as good, and the intended adhesive tape was obtained.

(Comparative Examples 1 and 2) In Comparative Example 1 in which the blending amount of the styrene resin of Example 1 was changed to 5 parts by mass, workability was not obtained because the film substrate was too soft. In Comparative Example 2 in which the blending amount of the styrenic resin in Example 1 was changed to 100 parts by mass, the film substrate became hard, and flexibility, elongation, wear resistance, and hand cutting properties were not obtained, and terminal peeling occurred. The tape cut surface became white.

(Comparative Examples 3 to 4) In Comparative Example 3 where the blending amount of the maleimide copolymer of Example 1 was changed to 0.5 parts by mass, the heat shrinkage rate of the film substrate was poor, and further flame retardancy was obtained. There wasn't. In Comparative Example 4 in which the blending amount of the maleimide copolymer of Example 1 was changed to 100 parts by mass, the film substrate became hard, and abrasion resistance, flexibility and workability were not obtained, and terminal peeling occurred, and the tape The cut surface became white.

(Comparative Examples 5-6) In Comparative Example 5 in which the amount of magnesium hydroxide in Example 1 was changed to 0.5 parts by mass, flame retardancy was not obtained. In Comparative Example 6 in which the blending amount of magnesium hydroxide in Example 1 was changed to 250 parts, the film base material was not stretched and the tape cut surface was whitened.

(Comparative Example 7) In Comparative Example 7 in which the magnesium hydroxide average particle diameter of Example 1 was changed to 25.0 μm, the film substrate became hard, and flexibility, elongation and abrasion resistance were not obtained, and terminal peeling occurred. Occurred and the tape cut surface became white.

Although not shown in Table 1, the heat deformation rate of Example 1 was −43%. This heat deformation rate is the deformation rate of the length in the longitudinal direction of the pressure-sensitive adhesive tape that had been heat-treated at 140 ° C. for 5 minutes and then left at 23 ° C. for 30 minutes or longer, and the temperature dependence of the pressure-sensitive adhesive tape. It shows sex. As another example, when the film base material of Example 1 was crosslinked by irradiation with an electron beam of 20 Mrad, the heating deformation rate was −6%, and the temperature dependency was reduced. In Examples 1 and 2, the tensile strength, breaking elongation, electrical insulation (volume resistivity value of 1 × 10 ¹² Ω · cm or more), electrical resistance and breakdown voltage equivalent to those of conventional polyvinyl chloride tapes are used. It was equipped with.

Claims (7)

(A) 10-60 parts by mass of a styrene resin, (b) 1-50 parts by mass of a maleimide copolymer, (c) aluminum hydroxide, magnesium hydroxide, hydro A film group comprising 1 to 200 parts by mass of an inorganic filler which is at least one compound selected from the group consisting of talcite and magnesium carbonate and whose average particle size is 20 μm or less as measured by a laser diffraction method Wood.   The film substrate according to claim 1, wherein the aromatic vinyl elastomer is a styrene-butadiene random copolymer, a styrene-butadiene block copolymer and / or a hydrogenated product thereof.   The film substrate according to claim 1 or 2, wherein the styrenic resin is polystyrene resin (GPPS) or rubber-reinforced polystyrene (HIPS).   A maleimide copolymer is obtained by polymerizing 15 to 70% by mass of an aromatic vinyl monomer and 30 to 85% by mass of an unsaturated dicarboxylic imide derivative, and the aromatic vinyl monomer is styrene or the unsaturated dicarboxylic acid. The film substrate according to any one of claims 1 to 3, wherein the imide derivative is N-phenylmaleimide.   The film substrate according to any one of claims 1 to 4, wherein the film substrate is irradiated with an electron beam and crosslinked.   The adhesive tape which formed the adhesive layer in the single side | surface of the film base material as described in any one of Claims 1-5.   An adhesive tape for bundling using the adhesive tape according to claim 6.