JPH0550389B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a laminated film mainly composed of biaxially oriented polyparaphenylene sulfide film. [Conventional technology] As electric equipment becomes smaller and lighter, has higher performance, and increases in capacity, the reliability of insulation systems has improved.
There is a growing demand for insulating materials that have a well-balanced combination of heat resistance, electrical properties, mechanical strength, and workability. Further, as a material having both of these properties, a biaxially oriented polyparaphenylene sulfide film has been proposed in Japanese Patent Application Laid-Open No. 55-35459 and other publications. [Problems to be solved by the present invention] However, although the conventional biaxially oriented polyparaphenylene sulfide film has properties such as heat resistance, electrical properties, and flame retardancy, it is difficult to apply impact force. It had a serious drawback of being prone to delamination. This drawback has caused a big problem, especially when inserting an insulating material in the production process of motors and the like. The present invention aims to eliminate such drawbacks, namely:
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 the problems] The present invention provides that 70 mol% or more of the repeating units have the structural formula

[Formula], consisting of a biaxially oriented polyparaphenylene sulfide film (A) with a thickness of 50 to 200 μm, a copolymerized polyamide with a softening point of 50°C or more and 200°C or less, and at least 2
The composition is made of a polyfunctional epoxy resin having at least three epoxy groups, the weight ratio of the copolyamide and the epoxy resin is in the range of 90:10 to 50:50, and the thickness is 10 to 45 μm. It is characterized by a biaxially oriented polyparaphenylene sulfide laminated film in which an adhesive layer (B) and an adhesive layer (B) are laminated in an A/B/A arrangement. Polyparaphenylene sulfide (hereinafter abbreviated as PPS) in the present invention has the structural formula

Refers to a product containing 70 mol% or more, preferably 90 mol% or more of the repeating unit represented by the formula. The remaining 30 mol% of the repeating units of the polymer
Orthophenylene sulfide for:

[Formula] Metaphenylene sulfide

[Formula] Ether

[Formula] Sulfone

[Formula] biphenyl

[Formula] Naphthyl

[Formula] Nuclear substituted phenyl sulfur Ido

[Formula] (where R is selected from an alkyl group having 1 to 10 carbon atoms, an alkoxy group, a nitro group, a phenyl group, and a sulfonic acid group), trifunctional phenyl sulfide

[Formula] etc., but the content of such copolymerization component is preferably 10 mol% or less. Furthermore, other components such as polymers, additives, inorganic fillers, etc. mixed for other purposes may be contained in the composition in an amount of 10% by weight or less, preferably 5% by weight or less. The characteristic melt viscosity of PPS in the present invention is determined by the temperature
Under the conditions of 300℃ and apparent shear rate of 200sec ^-1 ,
From the viewpoint of film formability, etc., the range is preferably 500 to 20,000 poise (more preferably 700 to 12,000 poise). The biaxially oriented PPS film (A) is a film having a thickness of 50 to 200 μm obtained by melt-molding the above PPS to form a sheet, biaxially stretching it, and heat treating it.
In addition, the degree of orientation measured from the two directions of Edge and End using wide-angle X-ray diffraction is both 0.10.
It is preferably in the range of ~0.60. Moreover, those having a breaking strength of 13 kg/mm ² or more are preferable. Here, the degree of orientation measured from the Edge direction (or End direction) is the degree of orientation measured from the direction parallel to the film surface and also parallel to the width direction (or longitudinal direction).
The intensity of diffraction from the (200) plane of the PPS crystal is the same as the degree of blackening (Iφ=0°) when scanning the equatorial line in the radial direction with a microdensitometer. It is defined by the ratio of the degree of blackening in the 30° direction (Iφ=30°): Iφ=30°/Iφ=0°. The thickness of the biaxially oriented PPS film used in the present invention is
The range is 50 to 200μm, and 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 PPS film (A) on both sides, and the thicknesses thereof may be different as long as they each have a thickness of 50 to 200 μm; From the viewpoint of curling of the laminate, it is more preferable that each of them be within ±20% of the average thickness of both. In addition, the surface of the biaxially oriented PPS film may be treated with corona discharge treatment, plasma treatment, chemical treatment (processing to activate the surface with chemicals to improve adhesiveness), or primer coating to improve adhesiveness. It goes without saying that the present invention also includes those in which the treatment is performed alone or in combination. The copolyamide in the composition of the adhesive layer (B) in the present invention is composed of a combination of amide units represented by the following structural formulas () and (), and the composition of () and () is The percentage of
Refers to a polymer in which () is in the range of 5 to 150 parts (more preferably 10 to 100 parts) per 100 parts. In the structural formula ()

[Formula] is a residue of a dimer acid, and R ₁ is a hydrocarbon group having 4 to 50 carbon atoms. Furthermore, the dimer acid referred to herein is a dimer of unsaturated carboxylic acid, and examples include dimers of dodecenoic acid, tetradecenoic acid, linoleic acid, and linolenic acid. In the structural formula ()

[Formula] is a residue of aliphatic dicarboxylic acid, and R ₂ has 0 to 0 carbon atoms.
50 hydrocarbon groups. Examples include oxalic acid, adipic acid, azelaic acid, and sebacic acid. Also, in the structural formulas () and ()

[Formula] and

〔Effect of the invention〕

The laminated film of the present invention has a structure in which two biaxially oriented PPS films with a specific thickness are laminated via an adhesive layer with a specific thickness mainly composed of a composition consisting of copolyamide and epoxy resin. By doing so, we have improved the impact resistance, which was a drawback of conventional biaxially oriented PPS films, without sacrificing the excellent properties inherent to biaxially oriented PPS films such as heat resistance, electrical properties, and flame retardancy. The characteristics have been greatly improved, for example,
It has excellent processing suitability in motor manufacturing processes, etc. [Function] It is not clear why the laminated film of the present invention exhibits the above-mentioned excellent impact resistance, but the impact energy applied to the laminate is absorbed by the adhesive layer with appropriate thickness and softness. It is thought that this is because it is absorbed by Next, methods for measuring characteristics and evaluation criteria used in describing the present invention will be described. (1) Optical orientation Set the sample film in a polarizing microscope equipped with orthogonal polarizers so that the film surface is perpendicular to the optical axis, and then set the sample film at a 45° angle to the analyzer axis.
Insert it so that it has an azimuth angle of . Next, rotate the sample around the optical axis and move it to the phase reduction position (the position where the phase difference caused by the sample is reduced by the compensator) which is in the direction of plus or minus 45 degrees from the extinction position. At this time, the optical path difference Γ ₀ caused by the birefringence of the sample is determined from the compensation value of the compensator, and the degree of optical orientation n〓−n〓 is defined as Γ ₀ /d ₀ (here, d ₀ 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, measurements were performed using a polarizing microscope POH type manufactured by Nippon Kogaku, a universal stage manufactured by Leit Z, and a compensator manufactured by Leit Z, using monochromatic light of the sodium D line (wavelength 0.5893 μm). (2) Characteristic melt viscosity (μ ₀ ) Using a Koka type float tester with a capillary die of length L and radius R, the pressure P at temperature T was measured.
When the volume discharge amount when extruding the polymer is Q, the apparent shear stress τ, the apparent shear rate γ·, and the apparent viscosity μ are defined as follows. τ=(RP)/(2L) γ・=(4Q)/(πR ³ ) μ=τ/γ・ At this time, the curve μ=f obtained by plotting μ at that time for various γ・(γ・), γ・
= 200 (seconds) Define the characteristic melt viscosity μ ₀ with the value at ^-1 . In the present invention, a die with L=10 mm and R=0.5 mm was used, and values measured at T=300° C. were used. (3) Para-phenylene sulfide structure in polymer

Composition ratio P of [Formula] Generally, poly-para-phenylene sulfide is synthesized by reacting para-dihalobenzene with a sulfur source represented by alkali sulfide in a solvent. In addition to this para-dihalobenzene, by adding other units such as meta-dihalobenzene and trihalobenzene,

Repeating structural units other than [formula] generate. Therefore, in the polymer

[Formula] The composition ratio of the structure can be estimated as follows. That is, the amount of para-dihalobenzene charged before polymerization is
(mol) The amount of copolymer components other than para-dihalobenzene before polymerization is Y (mol) The amount of unreacted para-dihalobenzene remaining after polymerization is j (mol) The amount of unreacted copolymer components remaining after polymerization k
(mol), then

〔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 32.6 kg of sodium sulfide in an autoclave
(250 mol, containing 40% by weight of water of crystallization), 100 g of sodium hydroxide, 36.1 g of sodium benzoate
Kg (250 mol) and 79.2 Kg of N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP) were charged, the temperature was gradually raised to 205°C with stirring, and water
7.0 of distillate containing 6.9 Kg was removed. 1,4-dichlorobenzene 37.5Kg in the residual mixture
(255 mol) and NMP20.0Kg and heated to 265℃.
Heated for 24 hours. The reaction product was washed 8 times with boiling water, μ ₀ , 2900 poise, N.1.17, T _g 91°C,
High polymerization degree PPS21.1Kg) yield with T _n 285℃
78%). (b) Melt molding The composition obtained in (a) 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, 40 mmφ
Put it into the hotspot of the extruder. 310
The composition melted at
The film was extruded through a die with a linear lip of 3.5 mm, cast onto a metal drum whose surface temperature was kept at 30°C, and cooled and solidified to obtain six types of films with different thicknesses. The resulting film has a density of 1.315 and a width of 230
mm, thickness 670μm, 940μm, 1200μm,
These are unstretched films of 1900 μm, 2400 μm, and 3010 μm. (c) 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.
Next, the film was 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 for 10 minutes in a subsequent heat treatment chamber in the same tenter.
After heat treatment for seconds, the thickness is 50μm, 70μm, 90μm,
Six types of biaxially oriented PPS films of 140 μm, 180 μm, and 230 μm were obtained. The degree of optical orientation of the film was 0.012, and the tensile strength at break was 25 Kg/mm ² in the longitudinal direction and 23 Kg/mm ² in the width direction, which satisfied the conditions for a biaxially oriented PPS film used in the present invention. . Further, the surface of the film was subjected to a corona discharge treatment of 6000 J/m ² , and the films were designated as Film-1 to Film-6. (2) Preparation of adhesive Dimer acid copolyamide (Henkel product) “Macromelt” 6901 ( _C36 unsaturated carboxylic acid, 80% by weight,
Dimer acid copolyamide consisting of 20% by weight of _C9 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 Ciel Co., Ltd.) "Epicoat" ”834 30% by weight, 2% by weight of imidazole was added as a hardening agent for epoxy resin, and methyl alcohol/
The mixture was stirred in a mixed solvent of monochlorobenzene/benzyl alcohol (30/50/20) until completely dissolved, to obtain an adhesive solution with a solid content concentration of 30% by weight and a viscosity of 2 poise. (3) Formation of laminated film The adhesive solution obtained in step (2) was applied to the corona discharge treated surfaces of films 1 to 6 obtained in step (1) using a reverse roll coater and heated at 140°C for 3 minutes. Dry. At this time, the thickness of the adhesive layer after the solvent was removed was adjusted so that the ratio (α/β) of the film thickness (α) to the thickness of the adhesive layer (β) was 5.0. Next, another layer of films 1 to 6 was applied to the biaxially oriented PPS film provided with the adhesive layer.
(with the corona discharge treated side of each film facing the adhesive layer) with films of the same thickness,
Lamination was performed using a roll lamination method at a temperature of 130°C. Further, the laminated film was cured at 150°C for 2 hours. The thicknesses of the laminated films thus obtained were 110 μm, 154 μm, 198 μm, and
They were 308 μm, 396 μm, and 506 μm. These laminated films are referred to as laminates 1-1 to 1-6. (4) Evaluation Table 1 shows the evaluation results of the produced laminated film in comparison with a conventional biaxially oriented PPS film. From vote 1, the impact resistance of the laminated film of the present invention is significantly improved compared to a single biaxially oriented PPS film of similar thickness. Furthermore, more 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, the heat resistance is not lower than that of conventional biaxially oriented PPS film alone.

[Table] Example 2 (1) Creation of laminated films Seven types of laminated films were created in the same manner as in Example 1, with only the thickness of the adhesive layer being changed. Both were 90 μm (laminates 2-1 to 2-
7). (2) Evaluation Table 2 shows the evaluation results of the obtained laminated film. From this result, the range of adhesive layer thickness that satisfies both impact resistance and heat resistance is from 10 μm to
It can be seen that the diameter is 45 μm. That is, if the thickness of the adhesive layer is less than 10 μm, 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】

[Table] 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 (Laminated body 3-1 to Laminated body 3-
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 3% based on the amount of epoxy resin. Further, the thickness of the adhesive layer was kept constant at 22 μm. 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. From Table 4, it can be seen that the weight ratio of copolyamide and epoxy resin that satisfies both impact resistance and heat resistance is copolyamide/epoxy resin = 90/10 to 50/50. In other words, the weight ratio of copolyamide and epoxy resin is 90:10.
If it exceeds 50:50, the heat resistance will decrease, and if it is less than 50:50, the impact resistance will deteriorate.

【table】

Claims (1)

[Claims] 1. 70 mol% or more of the repeating units consist of a biaxially oriented polyparaphenylene sulfide film (A) with a thickness of 50 to 200 μm, mainly consisting of a softening point is composed of a copolyamide with a temperature of 50°C or more and 200°C or less, and a multifunctional epoxy resin having at least two or more epoxy groups in one molecule, and the weight ratio of the copolyamide and the epoxy resin is 90:10 to 90:10. A biaxially oriented polyparaphenylene sulfide laminated film comprising an adhesive layer (B) having a composition in the range of 50:50 and having a thickness of 10 to 45 μm and laminated in an A/B/A arrangement.