JPS61241142A - Biaxial oriented polyparaphenylenesulfide laminated film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laminated film mainly composed of biaxially oriented polyparaphenylene sulfide film.

[Conventional technology]

Along with improving the reliability of insulation systems as electrical equipment becomes lighter, has higher performance, and larger capacity.

There is a growing demand for insulating materials that have a well-balanced combination of heat resistance, electrical properties, mechanical strength, and workability.

A polyparaphenylene sulfide film has been proposed.

[Problems to be solved by the present invention]

However, although conventional biaxially oriented polyparaphenylene sulfide film has properties such as #I thermal properties, electrical properties, and flame retardancy, it causes delamination when an impact force is applied. It had a major drawback: it was easy to use. This drawback has caused problems especially when inserting an insulating material in the production process of motors and the like.

The present invention aims to eliminate such drawbacks, viz.

The present invention aims to improve the impact resistance of a biaxially oriented polyparaphenylene sulfide film without deteriorating its properties such as heat resistance and electrical properties, thereby providing an even more excellent electrical insulating material.

[Means for solving problems]

In the present invention, 70 moles or more of repeating units have the structural formula +
A biaxially oriented polyparaphenylene sulfide film (A) consisting of Os+ and having a thickness of 50 to 200 μm, and a copolymerized polyamide mainly having a softening point of 50°C or more and 200°C or less, and at least two or more in one molecule. is made of a polyfunctional epoxy resin having an epoxy group, and the weight ratio of the copolyamide and the epoxy resin is 90:10 to 50:5.
0 and has a thickness of 10 to 45 pm.
The invention is characterized by a biaxially oriented polyparafluoride nylene sulfide laminate film in which an adhesive layer (B) and an adhesive layer (B) are laminated in an A/B/A arrangement.

Polybara phenylene sulfide (hereinafter p) in the present invention
(abbreviated as ps) means a structural formula of - or more, preferably 90
Refers to anything containing more than mulch. The remaining 30 moles of repeating units of the polymer (where R is an alkyl group having 1 to 10 carbon atoms, an alkoxy group, a nitro group, a phenyl group, a sulfo group) is preferably 10 moles or less. Preferably, the composition may further contain other components such as polymers, additives, inorganic fillers, etc. mixed in for other purposes in an amount of 10 parts by weight or less, preferably 5 parts by weight or less. do not have.

The characteristic melt viscosity of P/PS in the present invention is
℃ and an apparent shear rate of 200 seo.
500 to 20,000 voices (more preferably 700 to 1
2000 poise) is preferable from the viewpoint of film formability and the like.

The biaxially oriented pps film (A) is a film having a thickness of 50 to 200 ium obtained by melt-molding the above pps to form a sheet, biaxially stretching it, and heat treating it. Also,
The degrees of orientation measured from the two directions of Edge and End using wide-angle X-ray diffraction are both 0.10 to 0.
Preferably, it is in the range of 60.

Further, it is preferable that the breaking strength is 13]q (7 mm or more).

Here, the degree of orientation measured from the Edge direction (or End direction) refers to the degree of
The intensity of diffraction from the (200) plane of the pps crystal is the same as the degree of blackening (mmφ-0'') when scanning the equatorial line in the radial direction with a microdensitometer after taking a photo of the line plate.
Ratio of blackening degree in 50° direction (mmmm φ-30'''): φ-3
It is defined by 0°/Iφ=0″.

The thickness of the biaxially oriented PPS film used in the present invention is 50~
200μm range, even if it is less than 50μm, 200μm
Even if the thickness exceeds m, the effect of improving impact resistance by laminating is poor.

The laminated film of the present invention has the above-mentioned biaxially oriented pp on both sides.
s films (A), each of which has a thickness of 5
The thicknesses may be different as long as they are 0 to 200 μm, but it is more preferable that the thicknesses be within ±20 of the average thickness of the two layers in terms of curling points of the laminate. In addition, for the purpose of improving adhesiveness on the surface of the biaxially oriented PPS film, corona discharge treatment, plasma treatment, chemical treatment (processing to activate the surface with chemicals to improve adhesiveness)
It goes without saying that the present invention also includes those in which surface treatments such as ply and macoat are applied alone or in combination.

The copolyamide in the composition of the adhesive layer (B) in the present invention is composed of a bond of amide units represented by the following structural formula (η and (6)),
) and (6) are (6) to (9100 copies).
) is in the range of 5 to 150 parts (more preferably 10 to 10 parts)
Part 0).

R1 is a hydrocarbon group having 4 to 50 carbon atoms.

Furthermore, the dimer acid mentioned here is a dimer of unsaturated carboxylic acid, and an example thereof is dodecenoic acid.

It is a residue of a phosphoric acid such as tetradecenoic acid, linoleic acid, or linoleic acid, and R2 is a hydrocarbon group having 0 to 50 carbon atoms. Examples include oxalic acid, adipic acid, azelaic acid,
These include sebacic acid.

H H and I are hydrocarbon groups having 1 to 50 carbon atoms, and R/ and Da may be the same. Examples thereof include ethylenediamine, propylene diamine, hexamethylene diamine, and the like.

Furthermore, R1 and R9 in structural formula (1) and structural formula (6
Copolyamides containing two or more types of R2 and R in ) are also included in the present invention, but in this case, the proportion of the composition is as follows:
Structural formula (η, i.e., based on 100 parts of the total amount of amide units containing the residues of the dimer acid.

Structural formula (i) That is, the total amount of amide units containing residues of aliphatic dicarboxylic acid is 5 parts to 150 parts (preferably 10 parts).
part to 100 parts).

Furthermore, the copolyamide referred to in the present invention satisfies the above conditions and has a softening point (AS'I'M E 28-51
(measured from T) is required to be 50°C or more and 200°C or less. In particular, the above-mentioned copolyamide having a softening point of 80° C. to 180° C. is preferable in terms of solubility in solvents, lamination properties, and properties after lamination.

On the other hand, the polyfunctional epoxy resin in the composition of the adhesive layer (B) can be any epoxy resin as long as it has two or more epoxy groups in one molecule.
Suitable examples include glycidyl ether type epoxy resins such as bisphenol type epoxy resins and novolac type epoxy resins;
Or ester type such as aromatic epoxy or cycloaliphatic epoxy.

Alternatively, ether ester type or glycidylamine type ones can be mentioned.

In the composition of the adhesive layer (B) in the present invention, the weight ratio (p:q) of the above-mentioned copolyamide ω) and the above-mentioned epoxy resin (q) is in the range of 90:10 to 50:50. and more than 60% by weight of the adhesive composition,
It consists of both of the above-mentioned acid compounds.

Other compositions that may be included in the adhesive composition of the present invention include 1
Examples include lubricants, inorganic fibers, inorganic additives, antistatic agents, flame retardants, and hardening agents for epoxy resins, and they may be added as long as they do not impair the purpose of the present invention. Examples of curing agents for epoxy resins include amines, phenols, organic acids, organic acid anhydrides, dicyandiamide, boron fluoride, imidazole, and the like.

It is preferable to add these additives alone or in combination as appropriate.

The thickness of the adhesive layer after lamination is within the range of 10 to 45 μm. If the thickness is less than 10 μm, the impact resistance will not be improved sufficiently, and if it is thicker than 45 μm, the heat resistance of the laminated film will decrease.

Furthermore, the thickness (α) of one film (A) and the adhesive layer (
The ratio of the thickness φ) of B) is preferably 3≦α/β≦7 (However, when the thickness of the film (A) is different on both sides of the laminate, A is the arithmetic mean value thereof) .

Next, an example of the method for manufacturing the laminated film of the present invention will be described. However, the present invention is not limited to this method.

First, as a method for synthesizing pps used in the present invention, (
There are methods such as 1) reaction between P-dihalobenzene and sulfur, (2) reaction between P-dihalobenzene and alkali sulfide or alkaline earth metal sulfide, and (3) reaction between P-dithiophenol and inorganic alkali. Method (2), in which the reaction is carried out in a polar solvent at high temperature, is simple. The polymerization temperature is 2
Polymerization is carried out at 00°C to 350°C for 1 to 30 hours.

Here, the amount and type of additives such as polymerization regulators, stabilizers, and crosslinking agents are determined as necessary.

Further, the addition of an inorganic filler or the like to such a polymerization system does not impede the present invention in any way, and it may even be preferable to coexist with a filler having sufficient heat resistance.

The resulting powdered or granular polymer is washed with water or a solvent to separate the polymerization solvent, unreacted monomers, and the like. The polymer is then subjected to a drying process and provided as a polymer for use in the present invention.

This polymer can be formed into a biaxially oriented film using known methods. That is, a resin melted by an extruder is quantitatively cast from a die onto a cooling drum at 5°C to 50°C, and rapidly cooled to form a non-oriented, amorphous sheet.

Next, this sheet is sequentially biaxially or simultaneously biaxially stretched.
Preferably, a sequential biaxial stretching method is employed, in which the longitudinal direction (longitudinal stretching) is performed between rolls having different circumferential speeds, and then the transverse stretching is performed in a tenter. Next, the obtained biaxially stretched oriented film is heat-treated for a fixed length in the same tenter, and then relaxed as required. Relaxation can be achieved in the transverse direction by reducing the rail spacing by a certain ratio at the rear of the tenter, and in the longitudinal direction by reducing the peripheral speed of the roll by a certain ratio after exiting the tenter using a suitable device. In each case this ratio is within a few percent. In order to produce the PP5 biaxially oriented film used in the present invention in the process of manufacturing such a biaxially oriented film, longitudinal and lateral stretching conditions and heat treatment conditions are particularly important. That is, in the longitudinal stretching process, the stretching is carried out at a sufficiently large magnification within the range that allows transverse stretching, preferably so that the degree of optical orientation immediately before the transverse stretching is in the range of 0.10 to 0.20. The actual stretching temperature and stretching ratio vary depending on the polymer, but are generally preferably in the range of 90 to 110°C and 3.0 to 5.0 times.

Next, in the transverse stretching step, it is preferable that the degree of optical orientation after stretching is within a range of 0.05 or less. Actually the temperature is 95~
The 9-fold temperature for transverse stretching is determined by the strength of orientation of the film longitudinally stretched in the range of 3.0 to 4.5 times at 120°C. The subsequent heat treatment is performed within the range of 200 to 270°C.

Next, a method for manufacturing the adhesive used in the present invention will be described.

Commercially available copolyamides and epoxy resins, which are the main components of the adhesive, can be used.

Adhesives are generally prepared by dissolving them in a solvent.

The adhesive used in the present invention is soluble in solvents such as lower alcohols, dimethylformamide, monochlorobenzene, and N-methylpyrrolidone, but it is preferable to use a mixed solvent selected from these. A predetermined adhesive composition is prepared using the solvent to have a solid content concentration of 10 to 50% by weight and a viscosity of 1 to 10 poise. In addition, the required amount of curing agents, flame retardants, inorganic additives, etc. should be added at this time, but if a curing agent with a particularly fast curing speed is used, as much as possible should be added before lamination.
? Axial orientation d: It is preferable to subject the surface of the spoon rim to a surface treatment such as corona discharge treatment, plasma treatment, chemical treatment, primer coating, etc., either alone or in combination.

The method of laminating the film (A) and the adhesive layer (B) in an A/B/A arrangement is as follows: (1) Applying an adhesive prepared to a predetermined composition to one side of a biaxially oriented PPS film. After drying, another layer of biaxially oriented PPS film is bonded using a heated roll or heated press. (2) After applying the adhesive to paper or film coated with silicone or the like and having release properties and drying it to create an adhesive tape, peel this tape from the release paper or film and apply it with a heated roll or hot press. Two layers of biaxially oriented PPS films are sandwiched and bonded together. (3) After transferring the above tape to one of the biaxially oriented pps films using a heated roll or hot press, peel off the difficult-to-print paper or film, and attach the other biaxially oriented pps film in the same manner. (
4) While continuously peeling off the above tape from the release paper or film, a biaxially oriented pps film is attached to both sides of the tape using a heated roll. There are several methods, but method (1) is generally used. Furthermore, all of the above methods include a coating step.

The coating method is the reverse roll coater method.

Although there are gravure roll methods and the like, a reverse roll coater method is generally used. Dry the solvent after coating at 100℃
It is generally performed at 0 to 200°. Also,
The bonding conditions are: temperature 60℃, temperature 200℃, linear pressure 1~5
It is best to do this within the range of 0/(2).

The thickness of the adhesive layer is adjusted to fall within the range of 10 to 45 μm after lamination.

Next is the method of curing the adhesive, which varies depending on the composition of the adhesive9, but usually at a temperature of 80 to 200°C.
The minimum necessary conditions within the range of L50 hours are selected. In order to continuously cure a long object, the laminated film is rolled up in the open or a tenter is used.

〔Effect of the invention〕

The laminated film of the present invention consists of biaxially oriented PPS with a specific thickness.
By laminating two films with an adhesive layer having a specific thickness characterized by a composition consisting of a copolymerized polyamide and an epoxy resin, biaxially oriented PP can be produced.
Conventional biaxially oriented pps without sacrificing the excellent properties inherent to S film such as heat resistance, electrical properties, and flame retardancy.
The film's impact resistance, which had been a drawback, has been greatly improved, making it highly suitable for processing in, for example, motor manufacturing processes.

[Effect]

Although it is not clear why the laminated film of the present invention exhibits the above-mentioned excellent impact resistance, it is clear that the impact energy applied to the laminate is absorbed by the adhesive layer with appropriate thickness and softness. It is believed that this was done in order to

Next, methods for measuring characteristics and evaluation criteria used in describing the present invention will be described.

(1) Set the sample film in a polarizing microscope equipped with crossed Nicols optical orientation so that the film surface is perpendicular to the optical axis, and insert the sample so that it has an azimuth angle of 45° with respect to the analyzer axis. do. Next, the sample is rotated around the optical axis and placed at a phase reduction position (a position where the phase difference generated by the sample is reduced by the compensator) located in the direction of plus or minus 45 degrees from the extinction position. Optical path difference r caused by birefringence of the sample. is determined from the compensation value of the compensator, and the degree of optical orientation is expressed as I rO/dO.
(where d represents the thickness of the sample).

At this time, on the sample, the direction perpendicular to the rotation axis of the compensator is the α direction of the sample, and the parallel direction is the β direction.

In the present invention.

Nippon Kogaku polarizing microscope POH type.

Leit Z universal stage.

The measurement was performed using a convencator manufactured by Leit Z with monochromatic light of the sodium D line (wavelength: 0.5895 μm).

(2) Characteristic melt viscosity (μ.) ゛Length, radius H
When polymer is extruded at temperature T and pressure P using a Koka Type 70 tester with a capillary die of and the apparent viscosity μ are defined as follows.

τ-(RP)/(2L) Chi(4Q)/(πR) μ-τ/γ At this time, the curve μ-f (i) obtained by plotting μ at that time for 9 various Tes, r”-200 (seconds)
Characteristic melt viscosity μ with the value of . Define.

In the present invention, L W 10an, Rm 0.
A value measured at T=300° C. using a 5 mm die was used.

(3) Para-phenylene sulfite structure in g lima Constituent ratio of es÷P General niphorypara-722sulfide is.

It is synthesized by reacting para-dihalobenzene with a sulfur source such as alkali sulfide in a solvent.

By adding other units such as meta-dihalobenzene and trihelobenzene to this rosewood benzene, repeating structural units other than 48 are produced.

Therefore, the composition ratio of the 10es4 structure in the polymer can be estimated in a quadratic manner. That is.

If the charged amount of para-dihalobenzene before polymerization is x (mol), the charged amount of copolymer components other than para-dihalobenzene before polymerization is Y (mol), and the unreacted para-dihalobenzene remaining after polymerization (mol), - The composition ratio of the e-@s-) structure is P (mole).

In the present invention, the amounts of unreacted para-dihalobenzene and copolymerized components after 9-polymerization were determined by measuring the concentration of each component in the solvent after 9-polymerization by gas chromatography.

(4) Tensile properties Measured in the longitudinal direction according to ASTM D 882-64T.

(5) The heat-resistant sample was exposed to 200°C in an open state, and the sample was taken out every 240 hours and the tensile elongation rate was measured.
It is expressed as the time required to reach a value of 72.

(6) Impact resistance Measured using a Scotto type fir tester (manufactured by Toyo Baldwin). The sample was attached to the device, and the film was peeled off by applying reciprocating motion while being crimped.

(7) Degree of orientation measured from the Edge and End directions using wide-angle X-ray diffraction method (OF) When the stretching direction of each sample is aligned, the thickness is 1 cabinet 9 width 1-1 length 1
0ffl+! Formed into a rectangular shape (each film was fixed using a 5% acetic acid acyl acetate solution of collodion during molding),
X-rays are incident along the film surface (Edge and En
d direction) and a great photograph was taken. The X-ray generator was a D-3F type device manufactured by Rigaku Denki.1. N, 40kv-
20a+A TeNi FuiIL'l' through Cu
-K rays were used as the X-ray source.

Multiple exposures (15 minutes and 30 minutes) were carried out using Kodak non-screen type film with a sample-film distance of 41 mm.
) method was adopted. Next, the intensity of the (200) peak on the plate photograph was determined by φ-0″ (Equatorial Publishing) 10@, 20@,
The degree of blackening was read by scanning the densitometer in the radial direction from the center of the photograph at the 50'' position, and the degree of orientation (OF) of each sample was defined as OF'=Iφ-30/Iφ-=-0''.

Here, rφ-3 is the maximum intensity of 306 scans, Xφ-
0″ is the maximum intensity of equatorial line scanning. Note that Xφ=0@
are φ-00 and φ-180', Xφ, 30" is φ-3
The average value of the intensity at 0" and φ-150" was used. Here, the measurement conditions of the densitometer are as follows.

The device used was a Sukura microdensitometer model PDM-5 type A manufactured by Roku Konishi Photo Industry, and the measurement concentration range was O.
,Q-4,OD (minimum measurement i1 product 4 M w!i,)
.

The optical system magnification is 100x, the slit width is 1μ, the height is 10μ, the film movement speed is 50μ/sec, and the chart speed is 1.
It is Kaku/Second.

〔Example〕

Next, the present invention will be explained in detail by giving examples.

Example 1 (1) Preparation of biaxially stretched film used in the present invention (a
) Preparation of PPS Polymer Place 32.6 kg (25 kg) of sodium sulfide in an autoclave.
0 mol, crystallization water (including 40% by weight), sodium hydroxide 100g, sodium benzoate 36.1 kll (25
0 mol) and N-methyl-2-pyrrolidone C or less NMP
79.2 kg was charged and the temperature was gradually raised to 205°C while stirring to obtain a distillate containing 6.94 kg of water.
Ot was removed. 1,4-dichlorobenzene 37.5× (255 mol) and N M P 2 were added to the residual mixture.
Added 0.0 tow and heated at 265° C. for 24 hours. The reaction product was washed 8 times with boiling water and μ. , 2900 poise, N,
1.17. A high degree of polymerization p ps of 21.1 kg (yield 78 cm) having a Tg of 91°C and a Tm of 285°C was obtained.

0) Melt molding The composition obtained in the above (=) was heated at 180°C for 2 hours.

After drying under reduced pressure, 0.1% by weight of calcium stearate powder was added as a lubricant to the composition, and after stirring and mixing with a mixer, the mixture was charged into the hopper of a 40 mmφ extruder. The composition melted at 310″ a length 2
It was extruded from a die having a linear lip of 50 mm and a gap of 3.5 mm, cast on a metal drum whose surface temperature was maintained at 30° C., and cooled and solidified to obtain six types of films with different thicknesses.

The resulting film had a density of 1.315. Width 250m
, thicknesses of 670 μm, 940 μm, and 1200 μm.

1900pm, 24''OOpm, !1010pm unstretched film.

(O) Biaxial stretching and heat treatment The six types of films obtained in (b) above were stretched 3.9 times in the longitudinal direction of the film at a stretching temperature of 98°C using a longitudinal stretching device consisting of a group of rolls, and then The film is fed into a tenter, stretched 3.7 times in the width direction at a stretching temperature of 98°C, and further stretched at 240°C in a subsequent heat treatment chamber in the same tenter.
, heat treated for 10 seconds to a thickness of 50μm, 70pm, 90u
m, 140pm.

Six types of biaxially oriented PPS films of 180 um and 250 pm were obtained. The degree of optical orientation of the film is 0.012.
The tensile strength at break is 25 kg 7 mm in the longitudinal direction,
The weight in the width direction was 23 kg/no, which satisfied the conditions for a biaxially oriented pps film used in the present invention. Furthermore, 6000 J/W on the surface of the film? The films were designated as Film-1 to Film-6.

(2) Preparation of adhesive Dimer acid copolyamide (Henkel product) ``Macromelt'' 6901 (
C,6 unsaturated carboxylic acid, 80% by weight.

C, dimeric penta-acid copolyamide consisting of 20% by weight of dicarboxylic acid and 100% by weight of hexamethylene diamine (softening point: 160-175°C) 68% by weight; as epoxy resin, bisphenol A-based epoxy resin (product of Shell Co., Ltd.) "Epicoat" ″834 again. As a curing agent for epoxy resin, 2% by weight of imidazole was added, and methyl alcohol/sonochlorobenzene/benzyl alcohol (50% by weight) was added.
150/20) and stir until completely dissolved.

An adhesive solution having a solid content concentration of 30% by weight and a viscosity of 2 voids was obtained.

(3) Formation of laminated film The adhesive solution obtained in (2) was applied to the corona discharge treated surfaces of Films-1 to Film-6 obtained in (1) using a reverse roll coater, and the mixture was heated at 140°C for 3 minutes. Dry. At this time, the thickness of the adhesive layer after removing the solvent is the film thickness (
The ratio (α/β) of α) and adhesive layer thickness (β) is 5.0
Each was adjusted so that

Next, on the biaxially oriented pps film provided with the adhesive layer, another layer of films-1 to film-6 (with the corona discharge treated side of each film facing the adhesive layer) was placed on top of the biaxially oriented pps film with the same thickness. , temperature 130 by roll lamination method
Lamination 10um, 154μm, 308μm under ℃ conditions
, 396 μm.

It was 506 μm. These laminated films are made into laminate 1
-1 to laminate 1-6.

A comparison with an axially oriented pps film is shown.

From Tables 1 to 9, the laminate film of the present invention has significantly improved impact resistance compared to a single biaxially oriented pps film having a similar thickness. Furthermore, surprisingly, it can be seen that the impact resistance is improved even compared to a single film constituting the laminated film. On the other hand, l1lFl fever is
It is not lower than the conventional biaxially oriented PPS film alone.

Example 2 (1) Creation of laminated films In the same manner as in Example 1, seven types of laminated films were created in which only the thickness of the adhesive layer was changed (laminates 2-1 to 2-2).
7).

From this result, it can be seen that the range of the thickness of the adhesive layer that satisfies both impact resistance and heat resistance is from 10 μm to 45 μm. That is, if the thickness of the adhesive layer is less than 10 pm, the impact resistance will be poor, and if the thickness of the adhesive layer is more than 45 μm, the heat resistance will decrease.

Table 2 Example 3 (1) Preparation of laminated film A biaxially oriented pps film was prepared under the same conditions as in Example 1, with a film thickness of 120 μm and copolymerized polyamide and epoxy resin, which are the main components of the adhesive layer. Four types of laminated films were created with different composition ratios (laminate 3-1).
~ laminate 5-4).

The copolyamide and epoxy resin were the same as in Example 1, but the curing agent for the epoxy resin was changed to dicyandiamide, and the amount added was always adjusted to be 3 or more with respect to the amount of epoxy resin. The thickness of the adhesive layer is 22 μm.
I kept it constant. The solvent composition of the adhesive, the adhesive application method, and the lamination method are exactly the same as in Example 1.

(2) Evaluation Table 4 shows the evaluation results.

Table 4 shows that the weight ratio of copolyamide and epoxy resin that satisfies both impact resistance and heat resistance is copolyamide/epoxy resin I=90/10 to 50,150. That is, when the weight ratio of copolyamide and epoxy resin exceeds 90:10, heat resistance decreases, and when it falls below 50:50, impact resistance becomes poor.

Table 4

Claims (1)

[Claims] (1) More than 70 mol% of the repeating units consist of the structural formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, and the thickness is 50 to 2
00 μm biaxially oriented polyparaphenylene sulfide film (A
), a copolyamide with a softening point of 50°C or more and 200°C or less, and a polyfunctional epoxy resin having at least two or more epoxy groups in one molecule, and the weight of the copolyamide and the epoxy resin. The ratio is 90:10
~50:50, with a thickness of 10
A biaxially oriented polyparaphenylene sulfide laminate film in which a ~45 μm adhesive layer (B) is laminated in an A/B/A arrangement.