JP2020163855A - Laminate - Google Patents

Abstract

To provide a laminate excellent in adhesiveness, processability, heat resistance and moist heat resistance.SOLUTION: A laminate has a polyphenylene sulfide film 1 laminated via an adhesive 2 on each of the front and back sides of a polyethylene terephthalate film 3. In the laminate, the thickness of the polyethylene terephthalate film 3 is thicker than that of the polyphenylene sulfide film 1; the Martens hardness of the adhesive 2 is 1.0 N/mm2 to 4.0 N/mm2; the maximum value of thermal shrinkage at 150°C for 30 minutes of the polyethylene terephthalate film 3 is 0.1% to 3.0%; and the adhesion area ratio of the polyethylene terephthalate film 3 and the polyphenylene sulfide film 1 via the adhesive 2 after exposure to environment of 190°C for one hour is 95% or more.SELECTED DRAWING: Figure 1

Description

The present invention relates to a laminated body and is suitably used as electrical insulation of a motor.

As an insulating material for drive motors for electric vehicles and hybrid vehicles, and motors for compressors (for commercial, household, and in-vehicle air conditioners), polyester films with excellent balance of characteristics, heat resistance, chemical resistance, etc. Aramid non-woven films and polyphenylene sulfide films with enhanced properties, or laminates obtained by laminating them have been used.
In recent years, the operating temperature has risen due to the miniaturization and high output of motors, and the insulating materials used in motors are required to have improved durability in a high temperature environment. In addition, as the operating temperature rises, the number of oil-cooled motors that cool the motor by applying oil called automatic transmission fluid is increasing, and it is also required to improve the durability (oil resistance) of the insulating material against the automatic transmission fluid. ing. In addition, the automatic transmission fluid contains a small amount of water, and oil resistance and moisture heat resistance are also required. At the same time, with the spread of products, there is a high demand for reduction of manufacturing cost, and there is a demand for an insulator that is inexpensive and has excellent durability, and various studies have been made.
For example, a laminate in which an aramid non-woven fabric and a polyphenylene sulfide film having excellent durability are laminated on a relatively inexpensive polyester film has been studied. In Patent Document 1, a polyphenylene sulfide film is used as an adhesive on both sides of a polyethylene terephthalate film. Patent Document 2 discloses a laminate in which an aramid non-woven fabric is laminated on both sides of a polyethylene terephthalate film via an adhesive.

Japanese Unexamined Patent Publication No. 2016-163948 Japanese Unexamined Patent Publication No. 2006-262678

However, when the laminate using the adhesives of Patent Documents 1 and 2 is exposed to a high temperature environment, the heat resistance of the adhesive layer may be insufficient, and the leaching of the adhesive layer becomes a problem. .. In addition, the cohesive force of the adhesive layer may be insufficient, and peeling caused by applying shear stress to the interface between the adhesive layer and the film due to heat shrinkage of the film becomes a problem. Melting or peeling of the adhesive layer may reduce the electrical insulation of the laminate and the motor using the laminate.

The present invention is to improve the problems of the prior art and provide a laminate having excellent adhesiveness, processability, heat resistance, moisture heat resistance, and oil resistance. More specifically, it is suitably used as electrical insulation of a motor even in a harsh environment of high temperature.

In order to solve the above problems, the present invention has the following configuration.
(1) A laminate in which a polyphenylene sulfide film is bonded to both the front and back surfaces of a polyethylene terephthalate film via an adhesive.
The thickness of the polyethylene terephthalate film is thicker than that of the polyphenylene sulfide film.
The Martens hardness of the adhesive is 1.0 N / mm ² or more and 4.0 N / mm ² or less.
The maximum value of the heat shrinkage after heat treatment of the polyethylene terephthalate film at 150 ° C. for 30 minutes is 0.1% or more and 3.0% or less.
A laminate characterized by having an adhesive area ratio of a polyethylene terephthalate film and a polyphenylene sulfide film via an adhesive of 95% or more after being exposed to an environment of 190 ° C. for 1 hour.
(2) After immersing the laminate in an automatic transmission fluid and heat-treating at 150 ° C. for 10 hours,
The laminate according to (1), wherein the adhesive area ratio between the polyethylene terephthalate film and the polyphenylene sulfide film via the adhesive is 95% or more.
(3) The laminate according to (1) or (2), wherein the surface free energy of the surface to be bonded to the adhesive of the polyphenylene sulfide film is 50 mN / m or more and 60 mN / m or less.
(4) Any of (1) to (3), wherein the adhesive has a polyether resin and an isocyanate resin having an active hydrogen group, and / or an acrylic resin and an isocyanate resin having an active hydrogen group. The laminate described in Crab.
(5) The laminate according to (4), wherein the isocyanate resin is composed of a nurate-modified isophorone diisocyanate.
(6) The reaction equivalent ratio (NCO / OH) of the hydroxyl group of the polyether resin having an active hydrogen group or the active hydrogen group of the acrylic resin is a hydroxyl group, and the hydroxyl group of the isocyanate resin and the polyether resin having an active hydrogen group or the acrylic resin. The laminate according to (4) or (5), wherein) is 0.7 or more and 0.95 or less.

According to the present invention, a laminate satisfying adhesiveness, processability, heat resistance, and moisture heat resistance can be obtained, and it can be suitably used as electrical insulation of a motor even in a high temperature environment.

It is a side view of the laminated body which concerns on one Embodiment of this invention.

Hereinafter, the laminate of the present invention will be described.
The laminate of the present invention is a laminate having a polyphenylene sulfide film on both the front and back surfaces of a polyethylene terephthalate film via an adhesive layer. The polyethylene terephthalate film used in the present invention is a layer composed mainly of a polyethylene terephthalate resin having an ester bond having an ethylene terephthalate structure as the main bond chain of the main chain. It is preferable that the resin constituting the polyethylene terephthalate contains 80 mol% or more of the ethylene terephthalate component when comprehensively judging the quality, economic efficiency, etc., but as long as the effect of the present invention is not impaired, for example, ethylene-. Even if the constituents such as 2,6-naphthalate, butylene terephthalate, ethylene-α, β-bis (2-chlorophenoxy) ethane-4,4'-dicarboxylate are copolymerized in the range of 20 mol% or less. Good. Polyethylene terephthalate film has an excellent balance between characteristics and manufacturing cost, but it has difficulty in heat resistance and moisture heat resistance, and the usage environment may be limited.However, polyethylene terephthalate film has heat resistance and moisture heat resistance on both the front and back sides. Having a very good polyphenylene sulfide film makes it possible to dramatically improve performance.

The polyphenylene sulfide film used in the laminate of the present invention is, for example, a film containing 85 mol% or more of the paraphenylene sulfide unit represented by the following chemical formula (1) as a main component, and is paraphenylene sulfide. The content of the unit is preferably 90 mol% or more, more preferably 97 mol% or more, from the viewpoint of heat resistance. As the constituent component other than paraphenylene sulfide, a composition containing a phenylene sulfide component is preferable. For example, a metaphenylene sulfide unit, a biphenylene sulfide unit, a biphenylene ether sulfide unit, a phenylene sulfone sulfide unit, a phenylene carbonyl sulfide unit or a branch in a molecule. In order to introduce a chain, for example, a trifunctionalized component may be introduced by using 1,2,4-trichlorobenzene.

Various additives such as antioxidants, heat-resistant stabilizers, weather-resistant stabilizers, ultraviolet absorbers, organic lubricants, pigments, dyes, and organic substances are contained in the resins constituting the polyethylene terephthalate film and polyphenylene sulfide film of the present invention. Alternatively, inorganic fine particles, fillers, antistatic agents, nucleating agents, cross-linking agents and the like may be added to such an extent that the characteristics are not deteriorated.

The polyethylene terephthalate film and the polyphenylene sulfide film in the present invention must be biaxially oriented films, which have the main characteristics necessary for the function of the film, such as improvement of mechanical strength, improvement of thermal stability, improvement of chemical resistance, and improvement of electrical characteristics. Is expressed, which is preferable. The term "biaxial orientation" as used herein refers to a pattern showing a biaxial orientation pattern by wide-angle X-ray diffraction. The biaxially oriented polyester film is generally obtained by stretching an unstretched polyester sheet about 2.5 to 5.0 times in the longitudinal direction and the width direction of the sheet, and then heat-treating the sheet to complete the crystal orientation. be able to. The stretching in the longitudinal direction and the width direction may be a so-called sequential biaxial stretching method in which each is sequentially carried out individually, or a simultaneous biaxial stretching method in which the stretching is carried out at the same time.

In the laminate of the present invention, it is important that the thickness of the polyethylene terephthalate film is thicker than the thickness of the polyphenylene sulfide film, the thickness of the polyethylene terephthalate film is 75 μm or more and 300 μm or less, and the thickness of the polyphenylene sulfide film is 18 μm or more and 50 μm or less. Is preferable. Here, the thickness of the polyphenylene sulfide film refers to the total thickness of the polyphenylene sulfide film bonded to both the front and back surfaces of the polyethylene terephthalate film. If the thickness of the polyethylene terephthalate film is less than 75 μm, the mechanical strength and edge crack resistance of the laminate will decrease, and the laminate will tear or bend when it is molded as an electrically insulating film for motors. It may be inferior in workability. Here, the molding process as an electrically insulating film for a motor refers to a process of inserting a laminate into a place called a slot of a motor stator in which a coil is filled, and the laminate is U-shaped according to the shape of the slot. Refers to a series of steps of folding into a slot and inserting it into a slot. If it is 300 μm or more, the mechanical strength of the laminated body becomes too high, which makes it difficult to bend it into a U shape and may reduce workability. In addition, the ratio of the thickness of the polyethylene terephthalate film having low heat resistance to the polyphenylene sulfide film may become too large, and the heat resistance of the laminated body may decrease. When the thickness of the polyphenylene sulfide film is less than 12 μm, the ratio of the thickness of the polyethylene terephthalate film becomes large, and the heat resistance may decrease. When the thickness of the polyphenylene sulfide film is larger than 50 μm, the ratio of the thickness of the polyphenylene sulfide film becomes large, the edge crack resistance of the laminated body decreases, and there is a possibility that the polyphenylene sulfide film is torn when bent into a U shape. It can also be disadvantageous from an economic point of view.

In the laminate of the present invention, it is important that the Martens hardness of the adhesive is 1.0 N / mm ² or more and 4.0 N / mm ² or less. Martens hardness is measured and calculated by the ISO 14577 compliant indentation test method, and measured using an ultra-micro hardness test system (trade name: Picodenter HM500, manufactured by Fisher Instruments Co., Ltd.). Can be done. In this measuring method, a Vickers indenter, a diamond square cupola shape, and a maximum diameter of 400 μm can be used as the indenter. In order to eliminate the dependence on the thickness of the adhesive, the pushing load is set as small as 0.1 mN, and the pushing depth is set to be approximately 1 μm.

If the Martens hardness is less than 1.0 N / mm ² , the cohesive force and heat resistance of the adhesive are insufficient, and when the temperature of the motor rises, the adhesive portion foams and elutes, resulting in electrical insulation of the motor. It may be less sexual. If it is larger than 4.0 N / mm ² , the cohesive force of the adhesive layer is too high and the followability to the base film is poor, so there is a possibility that sufficient adhesion strength between the polyethylene terephthalate film and the polyphenylene sulfide film cannot be obtained. is there. The Martens hardness can be adjusted by changing the type of the polyether resin or the polyacrylic resin having an active hydrogen group, which will be described later, and the type and blending amount of the isocyanate resin.

In the laminate of the present invention, the maximum value of the heat shrinkage after heat-treating the polyethylene terephthalate film at 150 ° C. for 30 minutes is preferably 0.1% or more and 3.0% or less. The maximum value of the heat shrinkage rate after heat treatment at 150 ° C. for 30 minutes can be measured by the following method. First, a sample of 20 mm × 150 mm having a long side in an arbitrary direction is taken, heat-treated at 150 ° C. for 30 minutes, and then the dimensional change in the long side is measured by the method described in JIS C 2151 (2006). To do. Next, a 20 mm × 150 mm sample having a straight line obtained by rotating 5 ° to the right from the long side direction of the previous sample and performing the same measurement was taken, and this was taken as the long side direction of the first sample. Repeat until the angle of is 175 °. The value larger than all the obtained values is taken as the maximum value of the heat shrinkage rate. The heat shrinkage rate of 0.0% means that there is no change in dimensions before and after the heat treatment. When the polyethylene terephthalate film expands due to heating, the heat shrinkage rate shall be expressed in minus notation. When the maximum value of the heat shrinkage rate after heat treatment at 150 ° C. for 30 minutes is larger than 3.0%, shear stress is strongly applied at the interface between the adhesive and the polyethylene terephthalate film due to the large shrinkage, and the adhesive and the adhesive Peeling may occur at the interface of the polyethylene terephthalate film. If the maximum value of the heat shrinkage rate is less than 0.1%, a long time is required for the annealing treatment (heat treatment) described later, so that the heat load becomes too large and the smoothness of the polyethylene terephthalate film deteriorates, and the adhesive When the film is bonded to the polyphenylene sulfide film via the adhesive, the contact area with the adhesive may decrease and the adhesion strength may decrease. It can also be economically disadvantageous.

The method of setting the maximum value of the heat shrinkage rate after heat treatment at 150 ° C. for 30 minutes to 0.1% or more and 3.0% or less or the above-mentioned preferable range is not particularly limited as long as the effect of the present invention is not impaired. However, there is a method called annealing treatment in which the material is heated at a temperature of 150 ° C. to 180 ° C. and contracted by an oven or the like. The temperature in the annealing treatment is preferably 150 to 180 ° C., and the time for the annealing treatment is preferably 10 to 60 seconds. The polyethylene terephthalate film may be cut into a size that is easy to handle and then annealed, or it may be unwound from a roll and passed through an oven to be annealed, but continuous processing is possible and productivity is improved. A method of unwinding from a roll and passing through an oven is preferable because of its superiority.

It is important that the laminate of the present invention has an adhesive area ratio of 95% or more between the polyethylene terephthalate film and the polyphenylene sulfide film via an adhesive after being exposed to an environment of 190 ° C. for 1 hour. The adhesive area ratio is measured by the following method. First, a 100 mm × 100 mm laminated body sample is taken and heat-treated at 190 ° C. for 1 hour. Next, after measuring the mass of the sample after the heat treatment, the part where the film is peeled off and the part where air bubbles are generated between the films are located in the thickness direction so as to include the polyphenylene sulfide film and the polyethylene terephthalate film on the front and back sides. cut out. The mass of the sample after cutting is measured, and the ratio before and after cutting is defined as the adhesive area ratio. When the adhesive area ratio is less than 95%, when a temperature load is applied during motor operation, peeling occurs, which causes voids between the polyethylene terephthalate film, the adhesive, and the polyphenylene sulfide film, and the laminate and the motor. The electrical insulation of the film may decrease.

In the laminate of the present invention, the thickness of the polyethylene terephthalate film is thicker than the thickness of the polyphenylene sulfide film, the maltensity hardness of the adhesive is 1.0 N / mm ² or more and 4.0 N / mm ² or less, and the polyethylene terephthalate film. The maximum value of the heat shrinkage rate at 150 ° C. for 30 minutes is 0.1% or more and 3.0% or less, and the polyethylene terephthalate film and polyphenylene sulfide via an adhesive after being exposed to an environment of 190 ° C. for 1 hour. It is important that the adhesive area of the film is 95% or more. By satisfying all of these conditions, sufficient cohesive force and heat resistance can be imparted to the adhesive layer while ensuring the adhesion between the polyethylene terephthalate film and the polyphenylene sulfide film, so that each film and adhesive can be exposed to a high temperature environment. No peeling occurs between them, and electrical insulation can be ensured.

In the laminate of the present invention, the surface free energy of the surface to be bonded to the adhesive of the polyphenylene sulfide film is preferably 50 mN / m or more and 60 mN / m or less. Here, as the value of the surface free energy, water, ethylene glycol, formamide, and methylene iodide are used as four kinds of liquids whose values of the surface free energy and its respective components (dispersion force, polarity force, and hydrogen bond force) are known. It is obtained from the contact angle (θ) of each liquid on the film with a contact angle meter CA-D type (manufactured by Kyowa Interface Science Co., Ltd.). From the value of the contact angle and the intrinsic value of the dispersion force, polarity force, and hydrogen bond force of each liquid (according to Method IV by Panzer (described in Japan Adhesion Association magazine vol.15, No.3, p96)), the extended Fowkes formula and The values of dispersion force, polar force, and hydrogen bond force with respect to the film surface are obtained by using the following equations derived from Young's equation.
(ΓSd / γLd) 1/2+ (γSp / γLp) 1/2+ (γSh / γLh) 1/2 = (1 + cosθ) / 2
Here, γLd, γLp, and γLh are specific values of each component of the dispersion force, the polar force, and the hydrogen bond force of the measurement liquid, respectively (Method IV by Panzer (described in Japan Adhesion Association magazine vol.15, No.3, p96). Represents (according to), θ represents the average value of the contact angles of the measurement liquid on the measurement surface, and γSd, γSp, and γSh are the values of the dispersion force, polar force, and hydrogen bond force of the film surface, respectively. Represents. By solving the simultaneous equations obtained by substituting the eigenvalues and θ into the above equations, the values of the three components of the measurement surface are obtained. In the present invention, the sum of the values of the obtained dispersion force, polar force, and hydrogen bond force is taken as the value of the surface free energy.
When the surface free energy is less than 50 mN / m, the hydrophilicity of the surface is insufficient, so that the bond with the adhesive is weak and the adhesion may be poor. If it is larger than 60 mN / m, the outermost layer of the polyphenylene sulfide film may be significantly deteriorated by the corona discharge treatment described later, and sufficient adhesion may not be obtained.

As a method of setting the value of the surface free energy in a desired range, it is possible to apply a corona discharge treatment to the surface to be bonded to the adhesive of each film. The discharge treatment may be performed during the film manufacturing process or at a stage after the film is manufactured. Active oxygen atoms (oxygen radicals) are generated on the surface of the film by the discharge treatment, and the surface is oxidized to mainly form functional groups such as carbonyl groups and carboxyl groups in the main chain and side chains of the polymer. The hydrogen bonding force with these functional groups improves the adhesion between the polyphenylene sulfide film and the adhesive.
Examples of the corona discharge treatment method include corona discharge treatment performed in the atmosphere, corona discharge treatment performed in a nitrogen atmosphere, and corona discharge treatment performed in a mixed gas atmosphere of carbon dioxide gas and nitrogen gas, and may be used alone or in combination of two or more. May be applied with.
The treatment intensity during the corona discharge treatment can be appropriately selected within a range in which the effects of the present invention are not impaired, but is preferably 20 W · min / m ² or more and 300 W · min / m ² or less, more preferably 25 W ·. The effect of the present invention can be easily obtained by setting the value to min / m ² or more and 200 W · min / m ² or less, more preferably 30 W · min / m ² or more and 100 W · min / m ² or less. Further, as the processing strength of the discharge processing, the "E value" defined by the following formula can be used.
E value = [(applied voltage: V) x (applied current: A)] / [(processing speed: m / min) x (electrode width: m)]
The laminate of the present invention preferably has a polyether resin and an isocyanate resin having an active hydrogen group, and / or a polyacrylic resin and an isocyanate resin having an active hydrogen group. In order to suppress the hydrolysis of the polymer main chain in a high temperature and high humidity environment, it is important that the polyether resin and the polyacrylic resin have high durability against hydrolysis. Further, from the viewpoint of improving heat resistance, it is important to contain an isocyanate resin having high reactivity with an active hydrogen group in order to impart a crosslinked structure to the adhesive layer. Here, the active hydrogen group refers to a group having active hydrogen such as a hydroxyl group, a carboxyl group, a mercapto group and a primary or secondary amino group, and a hydroxyl group having high reactivity with an isocyanate resin is preferable.

Examples of the polyether resin having an active hydrogen group include oxylan compounds such as ethylene oxide, propylene oxide, butylene oxide and tetrahydrofuran, and low molecular weight polyols such as water, ethylene glycol, propylene glycol, trimethylolpropane and glycerin. Examples of the agent include a polyether polyol obtained by polymerization. In addition to bifunctional ones, trifunctional or higher functional ones can be used. It is also possible to use a plurality of combinations having different numbers of functional groups. Among them, a polyalkylene glycol or alkanediol monomer having a repeating unit having 3 or 4 carbon atoms and an organic diisocyanate are reacted at a predetermined ratio to synthesize the product, that is, a polyether polyurethane polyol is preferable. In the case of a polyether polyurethane polyol having a repeating unit having 1 or 2 carbon atoms, it is highly hydrophilic and tends to absorb moisture and swell easily, and as a result, it may be inferior in moisture and heat resistance. Since a polyether polyurethane polyol having a repeating unit having 5 or more carbon atoms has extremely high crystallinity, it may be difficult to prepare such a polyether polyurethane polyol.

Examples of the polyalkylene glycol used for the synthesis of the polyether polyurethane polyol include polytrimethylene glycol and polypropylene glycol, both of which have 3 carbon atoms in the repeating unit, and poly, which has 4 carbon atoms in the repeating unit. Examples thereof include tetramethylene glycol and polybutylene glycol. Among these, polyalkylene glycol containing at least one of polytetramethylene glycol and polypropylene glycol is preferably used, and more preferably polyalkylene glycol containing polytetramethylene glycol. This is because polytetramethylene glycol has high water resistance, moderate crystallinity, and high moist heat resistance.

Further, as the organic diisocyanate used for the synthesis of the polyether polyurethane polyol, it is preferable to use an aliphatic or alicyclic diisocyanate in which the isocyanate group is not directly bonded to the aromatic ring. Aliphatic or alicyclic diisocyanates are difficult to multimerize (for example, dimerize) even if they are deteriorated by heat, so that discoloration over time (discoloration to yellow) can be prevented.

The weight average molecular weight of the polyether resin having an active hydrogen group is preferably in the range of 35,000 to 70,000. When the weight average molecular weight is less than 35,000, the adhesive composition has insufficient initial cohesive force, and may cause floating between the films when the polyethylene terephthalate film and the polyphenylene sulfide film are adhered. On the other hand, when the weight average molecular weight exceeds 70,000, the initial cohesive force of the adhesive composition is sufficient, but the viscosity becomes too high, which may limit the coating method. Examples of the acrylic resin having an active hydrogen group include the following general formula (1).
CH ₂ = C (R1) -COO (R2) (1)
[In the formula, R1 is a hydrogen atom or a lower alkyl group, R2 is an alkyl group having 1 to 12 carbon atoms], or a homopolymer of a monomer represented by the monomer, or a structural unit based on the monomer. Copolymers can be used.

Specifically, polyacrylic acid esters such as methyl polyacrylate, ethyl polyacrylate, and butyl polyacrylic acid, polymethacrylic acid esters such as methyl polymethacrylate, ethyl polymethacrylate, and butyl polymethacrylate, and ethylene-acrylic. Acid ester copolymer, ethylene-acrylic acid ester-acrylic acid copolymer, styrene-methacrylic acid ester-acrylic acid copolymer, acrylic acid ester-vinyl chloride copolymer, acrylic acid ester-acrylic acid copolymer, It is possible to use one or a combination of two or more copolymers such as a methacrylic acid ester-vinyl chloride copolymer, a styrene-methacrylic acid ester-butadiene copolymer, and a methacrylic acid ester-acrylonitrile copolymer. it can.

The isocyanate resin may be any compound having a plurality of isocyanate groups in the molecule, and is not particularly limited. Examples of isocyanate resins include tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, tetramethylxylylene diisocyanate, naphthalene diisocyanate, and triphenylmethane triisocyanate. , Polyisocyanate compounds such as polymethylene polyphenyl isocyanate and the like. Further, these isocyanate resins may be used alone or as a mixture of two or more kinds. It can also be used as a denatured product such as an allophanate modified product, a burette modified product, and a nurate modified product. Of these, a nulate-modified isophorone diisocyanate, which has moderate flexibility and excellent adhesion, is excellent in hydrophobicity and cohesive force, and can improve moisture heat resistance and heat resistance, is preferable.

As for the compounding ratio of the isocyanate resin, the reaction equivalent ratio (NCO / OH) of the isocyanate group of the isocyanate resin to the hydroxyl group of the polyether resin having an active hydrogen group or the hydroxyl group of the acrylic resin is 0.7 or more and 0.95 or less. Is preferable. If it is less than 0.7, the cross-linking with the isocyanate resin may be insufficient and the heat resistance may be lowered. If it is more than 0.95, the cohesive force of the adhesive becomes too high and the adhesive becomes too hard, so that the adhesive strength between the films may decrease.

The adhesive of the present invention is a polyether resin having an active hydrogen group, or a poly having an active hydrogen group of an acrylic resin as a hydroxyl group, containing an isophorone diisocyanate resin of a nurate-modified product, and having an isocyanate group and an active hydrogen group of the isocyanate resin. Most preferably, the reaction equivalent ratio of the hydroxyl groups of the ether resin or acrylic resin is 0.7 or more and 0.95 or less. By satisfying all of these, while imparting sufficient cohesive force and heat resistance to the adhesive layer, it has excellent moisture and heat resistance as a resin skeleton, so even if it is exposed to a high temperature and high humidity environment, it peels off between each film and adhesive. Can be ensured and electrical insulation can be ensured. In addition, the durability against a small amount of water contained in the automatic transmission fluid can be improved, and both moisture and heat resistance and oil resistance can be imparted.

The adhesive is obtained by applying a coating material containing an adhesive on a polyethylene terephthalate film or a polyphenylene sulfide film by a coating method such as a roll coating method, a gravure roll coating method, a kiss coating method, or a printing method, and drying the adhesive. Can be formed. The coating amount of the adhesive agent is preferably ^1g / ^{m 2 ~30g} / m 2 by solid content in terms of ^{dry, 3g / m 2 ~20g / m} 2 is more preferable. If it is less than 1 g / m ^2, the cohesive force of the adhesive layer may be insufficient and the adhesion may be poor. If it exceeds 30 g / m ² , the shrinkage stress of the adhesive layer is too high, and the stress inside the roll when the laminated body is wound into a roll becomes too large, and wrinkles may occur. In addition, the productivity may be lowered due to the adhesion of debris during the cutting process to the adhesive layer portion of the cross section exposed by the slit or the punching process. In addition, it may be inferior in economic efficiency.

Various adhesives are heat-resistant stabilizers, oxidation-resistant stabilizers, UV absorbers, UV stabilizers, organic / inorganic lubricants, organic / inorganic adhesives, as necessary, as long as the effects of the present invention are not impaired. It may contain one or more kinds of additives such as fine particles, fillers, nucleating agents, dyes, coupling agents and adhesion imparting agents.

Preferred examples of the method for obtaining the laminate of the present invention are given below, but the present invention is not limited thereto.

As a method for obtaining the laminate of the present invention, it is preferable to produce the polyethylene terephthalate film by, for example, the steps shown below. The polyester raw material is melted at 270 to 320 ° C., formed into a film using a slit-shaped die, and then wound around a casting drum having a surface temperature of 20 to 70 ° C. to be cooled and solidified to obtain an unstretched film. Subsequently, the film is stretched 2.5 to 3.5 times in the longitudinal direction at 60 to 120 ° C. to obtain a uniaxially stretched film. Then, the uniaxially stretched film is introduced into the tenter, preheated at 100 to 140 ° C., stretched 2.5 to 4.0 times in the width direction, and heat-treated at 215 to 235 ° C. to obtain a biaxially oriented polyethylene terephthalate film. It was. Before the above-mentioned heat treatment, it is also possible to further stretch in the vertical or horizontal direction or in both the vertical and horizontal directions to increase the strength. The production method is not necessarily limited to the method shown here. It is also possible to manufacture by, for example, a simultaneous biaxial stretching method without adopting the above-mentioned two-step stretching method. Further, in order to reduce heat shrinkage when exposed to a high temperature environment, the polyethylene terephthalate film may be annealed. The annealing treatment can be performed, for example, by heating a polyethylene terephthalate film in an oven. The temperature in the annealing treatment is preferably 150 to 180 ° C., and the time for the annealing treatment is preferably 10 to 60 seconds. The polyethylene terephthalate film may be cut into a size that is easy to handle and then annealed, or it may be unwound from a roll and passed through an oven to be annealed, but continuous processing is possible and productivity is improved. A method of unwinding from a roll and passing through an oven is preferable because of its superiority.

Next, the polyphenylene sulfide film will be described, and it is preferable to produce it by, for example, the steps shown below. The polyphenylene sulfide raw material is melted at 290 to 360 ° C., formed into a film using a slit-shaped die, and then wound around a casting drum having a surface temperature of 20 to 70 ° C. to be cooled and solidified to obtain an unstretched film. Subsequently, the film is stretched 3.0 to 5.0 times in the longitudinal direction at 90 to 120 ° C. to obtain a uniaxially stretched film. Then, the uniaxially stretched film is introduced into the tenter, preheated at 90 to 120 ° C., stretched 2.0 to 4.0 times in the width direction, and heat-treated at 200 to 280 ° C. to obtain a biaxially oriented polyphenylene sulfide film. It was. The production method is not necessarily limited to the method shown here.

The laminate of the present invention can be obtained by laminating the polyethylene terephthalate film and the polyphenylene sulfide film thus obtained with an adhesive.

The laminate of the present invention has an adhesive area ratio of 95% or more between the polyethylene terephthalate film and the polyphenylene sulfide film via the adhesive after heat treatment at 150 ° C. for 10 hours in a state where the laminate is immersed in an automatic transmission fluid. Is preferable. Here, the automatic transmission fluid (hereinafter, may be abbreviated as auto fluid) refers to oil used for lubrication, cooling, and cleaning of an automobile transmission. The autofluid is not particularly limited as long as it is generally used, and is generally a base oil containing various additives. The base oil is generally a mineral oil-based base oil, a synthetic oil-based base oil, or a mixture thereof. Examples of the additive component include a viscosity modifier and a friction modifier. As the auto fluid, for example, Matic Fluid S (manufactured by Nissan Motor Co., Ltd.), Auto Fluid WS (manufactured by Toyota Motor Co., Ltd.), ATF DW-1 (manufactured by Honda Motor Co., Ltd.) and the like can be used.

When the adhesive area ratio of the polyethylene terephthalate film and the polyphenylene sulfide film via the adhesive is less than 95% after heat treatment at 150 ° C. for 10 hours with the laminate immersed in the automatic transmission fluid, the adhesive portion Due to foaming and elution, peeling occurs between the polyethylene terephthalate film and the polyphenylene sulfide film, which may reduce the electrical insulation of the laminate and the electrical insulation of the motor.

[Measurement method of physical properties]
Hereinafter, the configuration and effect of the present invention will be described in more detail with reference to Examples. The present invention is not limited to the following examples. Prior to the description of each embodiment, various methods for measuring physical properties will be described.

(1) Adhesion Strength The polyethylene terephthalate film and polyphenylene sulfide film of the present invention were bonded by the method described in Examples, and then aged in a constant temperature bath adjusted to 40 ° C. for 72 hours. Three measurement test pieces were cut out from the bonded samples in a strip shape with a width of 10 mm, the polyethylene terephthalate film side of the present invention was fixed horizontally, and the polyphenylene sulfide film side was peeled off at an angle of 180 ° and a tensile speed of 200 mm / min. Adhesion strength was measured by peeling off in this state. The measurement was performed once for each of the three strip-shaped test pieces, and the average value of the obtained strengths was taken as the value of the adhesion strength. The evaluation was performed according to the following criteria, and A and B were accepted.
A: Adhesion strength is 3N / 10mm or more B: Adhesion strength is 2N / 10mm or more and less than 3N / 10mm C: Adhesion strength is less than 2N / 10mm.

(2) Heat Shrinkage Rate First, a 20 mm × 150 mm laminated body sample having an arbitrary straight line as a long side was collected from the laminated body. Then, the front and back polyphenylene sulfide films and the adhesive were removed, and only the polyethylene terephthalate film was isolated. The isolated polyethylene terephthalate film was heat-treated at 150 ° C. for 30 minutes in an oven manufactured by ESPEC (GPH-202), and then the dimensional change rate in the long side direction was measured based on JIS C 2151 (2006). Next, a 20 mm × 150 mm sample having a straight line obtained by rotating 5 ° to the right from the long side direction of the previous sample and performing the same measurement was taken, and this was taken as the long side direction of the first sample. Was repeated until the angle of was 175 °. The maximum value of all the obtained values was taken as the maximum value of the heat shrinkage rate.

(3) Martens hardness The laminated body was cut on a plane perpendicular to the film plane using a microtome. Next, using a cutting device SAICAS (DN-20S type) manufactured by Daipla Wintes, only the polyphenylene sulfide film portion was cut off to expose the adhesive so as to have a size of 5 mm × 5 mm or more. By pushing an indenter into the exposed adhesive surface using an ultra-micro hardness test system (trade name: Picodenter HM500, manufactured by Fisher Instruments Co., Ltd.) based on the ISO 14577 compliant indentation test method. It was measured. In order to eliminate the dependence on the thickness of the adhesive, the pushing load was set as small as 0.1 mN, and the pushing depth was set to about 1 μm.

(4) Adhesive area ratio after exposure to 190 ° C. for 1 hour A measurement sample of 100 mm × 100 mm was taken from the laminate and heat-treated at 190 ° C. for 1 hour in an oven manufactured by ESPEC (GPH-202). Next, the mass of the sample after the heat treatment is measured, and the part where the film is peeled off and the part where air bubbles are generated between the films are located in the thickness direction so as to include the polyphenylene sulfide film on the front and back and the polyethylene terephthalate film. cut out. The mass of the sample after cutting was measured, and the ratio before and after cutting was defined as the adhesive area ratio, and the adhesive area ratio was evaluated according to the following criteria.
A: Adhesive area ratio is 98% or more B: Adhesive area ratio is 95% or more and less than 98% C: Adhesive area ratio is less than 95%.

(5) Measurement of surface free energy The contact angle was measured 5 times for each solution with water, ethylene glycol, formamide, and diiodomethane, and the average value of the contact angles for each liquid was calculated. Using the average value of the contact angles, the value of each component was calculated using the following formula introduced from the extended Fawkes formula and the Young formula.
(ΓSd / γLd) 1/2+ (γSp / γLp) 1/2+ (γSh / γLh) 1/2 = (1 + cosθ) / 2
Here, γLd, γLp, and γLh are eigenvalues of each component of the dispersion force, the polar force, and the hydrogen bond force of the measurement liquid, respectively (Method IV by Panzer (described in Japan Adhesion Association magazine vol.15, No.3, p96). Represents (according to), θ represents the average value of the contact angles of the measurement liquid on the measurement surface, and γSd, γSp, and γSh are the values of the dispersion force, polar force, and hydrogen bond force of the film surface, respectively. Represents. By solving the simultaneous equations obtained by substituting the eigenvalues and θ into the above equations, the values of the three components of the measurement surface are obtained. In the present invention, the sum of the values of the obtained dispersion force, polar force, and hydrogen bond force is taken as the value of the surface free energy.

(6) A measurement sample having a width of 10 mm and a length of 250 mm was collected from the stretch-stretched laminate so that the longitudinal direction of the laminate was the length direction. The sample was pulled in the long side direction based on JIS C 2151 (2006), and the elongation when the film broke was determined. The measurement was performed 5 times for each sample, and the average value of the 5 times was taken as the tensile elongation.
If the longitudinal direction cannot be specified, the above-mentioned measurement of the heat shrinkage rate is performed, and the direction in which the heat shrinkage rate is maximized is regarded as the longitudinal direction.

(7) Elongation Retention Rate A measurement sample having a width of 10 mm and a length of 250 mm was collected from the laminate so that the longitudinal direction of the laminate was the length direction. The cut out sample was treated in an oven manufactured by ESPEC (GPH-202) for 200 hours in an environment at a temperature of 180 ° C. The tensile elongation of the film before and after the treatment was measured based on JIS C 2151 (2006). The measurement was performed 5 times for each sample, and the average value of the 5 times was taken as the tensile elongation. Regarding the obtained tensile elongation, the value obtained by dividing the tensile elongation after the treatment by the tensile elongation before the treatment was evaluated as the elongation retention rate in the heat resistance evaluation according to the following criteria.
A: 70% or more B: 50% or more and less than 70% C: Less than 50%.

(8) A sample having a width of 20 mm and a length of 300 mm is collected from the end crack resistance laminate so that the longitudinal direction of the laminate is the length direction, and the test fitting B (V-shaped notch) is taken based on JIS C 2151 (2006). Type) was used for measurement. The obtained end crack resistance was evaluated according to the following criteria.
A: 750N / 20mm or more B: 300N / 20mm or more and less than 750N / 20mm C: 300N / 20mm or less.
If the longitudinal direction cannot be specified, the above-mentioned measurement of the heat shrinkage rate is performed, and the direction in which the heat shrinkage rate is maximized is regarded as the longitudinal direction.

(9) Adhesive area ratio after immersion in autofluid A measurement sample of 100 mm × 100 mm was collected from the laminated body. Next, the sample is immersed in a stainless steel container containing genuine Nissan Autofluid (Matic Fluid S) so that the entire sample is immersed in the Autofluid, and 0.5% by mass of water is added to the amount of Autofluid and sealed. , This sealed container was placed in an oven manufactured by ESPEC (GPH-202) and heat-treated at 150 ° C. for 10 hours. Next, the mass of the sample after the heat treatment is measured, and the part where the film is peeled off and the part where air bubbles are generated between the films are located in the thickness direction so as to include the polyphenylene sulfide film on the front and back and the polyethylene terephthalate film. I cut it out. The mass of the sample after cutting was measured, and the ratio before and after cutting was defined as the adhesive area ratio, and the adhesive area ratio was evaluated according to the following criteria.
A: Adhesive area ratio is 98% or more B: Adhesive area ratio is 95% or more and less than 98% C: Adhesive area ratio is less than 95%.

[Film used as each layer]
1. 1. Polyethylene terephthalate (hereinafter referred to as PET) Film A (PET-A)
100 parts by mass of dimethyl terephthalate and 60 parts by mass of ethylene glycol were mixed in a nitrogen atmosphere at a temperature of 260 ° C. After that, the temperature was lowered to 225 ° C., 0.08 parts by mass of calcium acetate and 0.029 parts by mass of antimony trioxide were added, and then 16.9 parts by mass of ethylene glycol was gradually added over 2 hours while stirring, and methanol was added. Was distilled off, and the transesterification reaction was completed. Then, 0.16 parts by mass of lithium acetate and 0.11 parts by mass of trimethyl phosphate were added, and the mixture was transferred to a polymerization reaction tank. Next, the polymerization reaction was carried out under reduced pressure at a final temperature of 285 ° C. and a pressure of 13 Pa to obtain a polyester having an intrinsic viscosity of 0.54 and a terminal carboxyl group number of 18 equivalents / t. The polyester is cut into rectangular parallelepipeds having a side of 2 mm × 4 mm × 4 mm, further dried at 160 ° C. for 6 hours, crystallized, and then subjected to solid phase polymerization at 220 ° C. for 20 hours under reduced pressure conditions of 65 Pa. A polyester resin pellet 1 having an intrinsic viscosity (IV) of 0.80, a carboxyl group terminal group amount of 10 equivalents / t, and a melting point of 260 ° C. was obtained.
Next, the polyester resin pellet 1 was dried in vacuum at 160 ° C. for 6 hours, then supplied to an extruder and melt-extruded at 295 ° C. After filtering the stainless steel fiber with a filter having an average opening of 60 μm, which is sintered and compressed, it is extruded into a sheet from a T-shaped base and wound around a mirror casting drum with a surface temperature of 20 ° C using an electrostatic application casting method to cool and solidify. I made it. At this time, the melting time of the resin from the tip of the extruder to the base is 2 minutes, and the wind speed is 20 m from a slit nozzle with a gap of 2 mm in which 12 stages of cold air having a temperature of 10 ° C. are installed in the longitudinal direction from the opposite surface of the casting drum. The film was sprayed at / s and cooled from both sides. After preheating this unstretched film to 80 ° C. with a preheating roll, the unstretched film is stretched 3.3 times in the longitudinal direction using the peripheral speed difference between the rolls while being heated to 90 ° C. using a radiation heater, and then used as a cooling roll. The film was cooled to 25 ° C. to obtain a uniaxially oriented film. Both ends of the uniaxially oriented film in the width direction were gripped with clips, preheated in an oven at an atmospheric temperature of 110 ° C., and subsequently continuously stretched 3.7 times in the width direction in a stretching zone at 120 ° C. The obtained biaxially oriented film is continuously heat-treated at a heat-fixing temperature of 215 ° C. for 10 seconds, and then the distance between the clips facing each other in the width direction is shortened while cooling from 215 ° C. to 160 ° C. to perform a 5.0% relaxation treatment. Was given. Then, after cooling to 100 ° C. in the oven, the film is taken out from the oven by separating the clips holding both ends in the width direction of the film, and both ends in the width direction are cut and removed to obtain PET film A having a winding thickness of 125 μm. It was. Table 1 shows the physical properties of the obtained film.

2. PET films B to K (PET-B to K)
PET films B to K were obtained in the same manner as PET film A except that the thickness, heat fixing temperature, and annealing time were as shown in Table 1. Table 1 shows the physical properties of the obtained film.

3. 3. Polyphenylene sulfide (hereinafter referred to as PPS) film L (PPS-L)
Add 100 mol parts of sodium sulfide 9 hydroxide, 45 mol parts of sodium acetate and 259 mol parts of N-methyl-2-pyrrolidone (NMP) to an autoclave, and gradually raise the temperature to 220 ° C. with stirring. , The contained water was removed by distillation. In the dehydrated system, 101 mol parts of p-dichlorobenzene as the main component monoma and 0.2 mol parts 1,2,4-trichlorobenzene as subcomponents were added together with 52 mol parts of NMP, and the temperature was 170 ° C. Nitrogen was pressurized and sealed at 3 kg / cm ² at the same temperature, then the temperature was raised and polymerization was carried out at a temperature of 260 ° C. for 4 hours. After completion of the polymerization, the polymer was cooled, the polymer was precipitated in distilled water, and a small mass polymer was collected by a wire mesh having a mesh opening of 150 mesh. The small lump polymer thus obtained was washed 5 times with distilled water at 90 ° C. and then dried under reduced pressure at a temperature of 120 ° C. to obtain PPS raw powder having a melting point of 280 ° C. The obtained PPS raw powder was extruded into a gut shape by a 30 mmφ twin-screw extruder at a temperature of 320 ° C. and then cut to obtain PPS resin pellets 1.
Next, 7% by weight of calcium carbonate powder having an average particle size of 1.0 μm was added to PPS resin 1, uniformly dispersed and blended, extruded into a gut shape by a 30 mmφ twin-screw extruder at a temperature of 320 ° C., and then cut. PPS resin pellets 2 containing calcium carbonate particles were obtained.
PPS resin pellet 1 and PPS resin pellet 2 are mixed at a weight ratio of 90:10, dried at a temperature of 180 ° C. for 4 hours under a reduced pressure of 3 mmHg using a rotary vacuum dryer, and then supplied to an extruder at 310 ° C. The melt extrusion was performed in. After filtering the stainless steel fiber with a filter with an average opening of 14 μm that is sintered and compressed, it is extruded into a sheet from a T-shaped base and wound around a mirror casting drum with a surface temperature of 25 ° C using an electrostatic application casting method to cool and solidify. I made it. This unstretched film is preheated to 92 ° C. with a preheating roll, then stretched 3.7 times in the longitudinal direction using the peripheral speed difference between the rolls while heating to 105 ° C. using a radiation heater, and then used as a cooling roll. The film was cooled to 25 ° C. to obtain a uniaxially oriented film. Next, both ends of the uniaxially oriented film in the width direction were gripped with clips, preheated in an oven at an ambient temperature of 100 ° C., and subsequently continuously stretched 3.4 times in the width direction in a stretching zone at 100 ° C. The obtained biaxially oriented film is continuously heat-treated in a heating zone of 260 ° C. for 6 seconds, and then the distance between the clips facing each other in the width direction is shortened while cooling from 260 ° C. to 200 ° C. to perform a 5.0% relaxation treatment. gave. Then, after cooling to 115 ° C. in the oven, the film is taken out from the oven by separating the clips holding both ends in the width direction of the film, both ends in the width direction are cut and removed, and the film is wound up after being conveyed by a conveying roll. A biaxially oriented film having a size of 16 μm was obtained. Next, the obtained film was subjected to corona discharge treatment with a treatment strength E value of 30 W · min / m ² on only one side in an air atmosphere to obtain a PPS film L. The characteristics of the obtained PPS film are shown in Table 2.

4. PPS film M to R (PPS-M to R)
PPS films M to R were obtained in the same manner as for PPS film L, except that the thickness and corona treatment strength E value were as shown in Table 2. Table 2 shows the physical properties of the obtained film.

5. Adhesives a to f, m to q
100 parts by mass of the dry laminating agent "DYNAGRAND" (registered trademark) LIS-7100 manufactured by Toyo Morton Co., Ltd. was cured as an adhesive having a hydroxyl group in the active hydrogen group as an adhesive for laminating PET film and PPS film. LCR-1032 manufactured by Toyo Morton Co., Ltd., which contains an adduct-modified hexamethylene diisocyanate resin as the main component, or Z4470BA manufactured by Sumika Cobestrourethane Co., Ltd., which contains a nurate-modified isophorone diisocyanate resin as the main component. And ethyl acetate were weighed according to the formulation shown in Table 3 and stirred for 15 minutes to obtain adhesives a to f and m to q having a solid content concentration of 33.5% by mass. The reaction equivalent ratios of the isocyanates of each adhesive and the polyether resins having active hydrogen groups are as shown in Table 3 as NCO / OH.

6. Adhesive g ~ l
"Leocoat" (registered trademark) S-8000E manufactured by Toray Coatex Co., Ltd. as a polyacrylic resin having a hydroxyl group in an active hydrogen group is used as an adhesive for laminating PET film and PPS film, and hexamethylene diisocyanate is used as a curing agent. Weigh "Coronate" (registered trademark) HL manufactured by Toso Co., Ltd., which contains a based resin as the main component, and ethyl acetate in the formulation shown in Table 4, and stir for 15 minutes to achieve a solid content concentration of 13.5 mass. Adhesives g to l, which are% adhesives, were obtained.

(Examples 1 to 30, Comparative Examples 1 to 10)
An adhesive was applied to the corona-treated surface of the PPS film using a wire bar, and dried at 80 ° C. for 60 seconds to form an adhesive layer. Next, the PET film was laminated so as to be in contact with the adhesive to prepare an intermediate laminate. Next, an adhesive was applied to the corona-treated surface of the newly prepared PPS film using a wire bar, and dried at 80 ° C. for 60 seconds to form an adhesive layer. The surface of the PET film of the intermediate laminate was laminated so as to be in contact with the adhesive of the newly prepared PPS film to obtain a laminate. The types of PET film, PPS film, and adhesive are as shown in Table 5. The characteristic evaluation results are shown in Table 6.

According to the present invention, it is possible to provide a laminate having excellent adhesiveness, processability, heat resistance, and moisture heat resistance. The laminate of the present invention can be suitably used as electrical insulation of a motor.

1: Polyphenylene sulfide film 2: Adhesive 3: Polyethylene terephthalate film

Claims (6)

It is a laminate in which a polyphenylene sulfide film is bonded to both the front and back surfaces of a polyethylene terephthalate film via an adhesive.
The thickness of the polyethylene terephthalate film is thicker than that of the polyphenylene sulfide film.
The Martens hardness of the adhesive is 1.0 N / mm ² or more and 4.0 N / mm ² or less.
The maximum value of the heat shrinkage rate of the polyethylene terephthalate film at 150 ° C. for 30 minutes is 0.1% or more and 3.0% or less.
A laminate characterized by having an adhesive area ratio of a polyethylene terephthalate film and a polyphenylene sulfide film via an adhesive of 95% or more after being exposed to an environment of 190 ° C. for 1 hour. The laminate is immersed in an automatic transmission fluid and heat-treated at 150 ° C. for 10 hours, and the adhesive area ratio between the polyethylene terephthalate film and the polyphenylene sulfide film via the adhesive is 95% or more. The laminate according to claim 1. The laminate according to claim 1 or 2, wherein the surface free energy of the surface to be bonded to the adhesive of the polyphenylene sulfide film is 50 mN / m or more and 60 mN / m or less. The laminate according to any one of claims 1 to 3, wherein the adhesive has a polyether resin and an isocyanate resin having an active hydrogen group, and / or an acrylic resin and an isocyanate resin having an active hydrogen group. body. The laminate according to claim 4, wherein the isocyanate resin is composed of a nurate-modified product of isophorone diisocyanate. The reaction equivalent ratio (NCO / OH) of the hydroxyl group of the polyether resin having an active hydrogen group or the acrylic resin is a hydroxyl group, and the hydroxyl group of the isocyanate resin and the polyether resin having an active hydrogen group or the acrylic resin is 0. The laminate according to claim 4 or 5, characterized in that it is 7 or more and 0.95 or less.

Images