JP2007031602A - Laminated film with adhesive for electric material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated film with an adhesive for electric materials, which is excellent in adhesiveness at a low temperature while retaining adhesiveness at room temperature to a high temperature, is excellent in temporary bonding before heat bonding of products in forming and is high in mass-productivity. <P>SOLUTION: The laminated film with an adhesive for electric materials comprises a substrate made of a plastic film and at least one adhesive layer provided onto at least one face of the substrate, wherein at least the surface layer of the adhesive layer has a polyester-based hot-melt adhesive containing a crystalline polyester based resin and an amorphous polyester based resin in a mass ratio of 80:20-99:1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a laminated film having an adhesive layer, and for example, relates to a laminated film with an adhesive for electrical materials used for covering core wires such as electric wires for wiring of electric devices and electronic devices.

The laminated film is useful as a constituent member such as a flat electric wire used for wiring of electrical equipment, electronic equipment, etc., and can be used for covering and insulating the core wire. A flat electric wire or the like is usually obtained by integrating a coated body to be coated and a laminated film by thermocompression using a heating roll or a heating press. For this reason, it is necessary to use for the laminated film an adhesive layer that can be melted by heating and integrated with the covering.
A laminated film having an adhesive layer is generally composed of a base material and an adhesive layer. In consideration of mechanical strength and electrical insulation, a biaxially stretched polyester film has been conventionally used as the base material. As a material constituting the adhesive layer, a hot-melt adhesive mainly composed of a vinyl chloride resin, a polyester resin, a polyolefin resin, or the like is used.
Further, usually, when it is necessary to impart flame retardancy to the laminated film, a flame retardant is added to the adhesive layer, and when it is necessary to impart concealability, a pigment or dye is added to the adhesive layer. Etc. are added.

As a polyester resin generally used as the material of the adhesive layer, in order to improve the adhesive strength at high temperature, a crystalline resin is used so as to maintain cohesive force at high temperature, or a resin having a high glass transition temperature. There are various methods such as cross-linking or resin cross-linking, but if it is necessary to secure adhesive properties at low temperatures, use an adhesive layer consisting only of a high glass transition temperature. I can't. Further, when using a method of crosslinking the resin, there is a restriction that it is necessary to pay sufficient attention when handling the product because the crosslinking proceeds even at room temperature.
Due to the limitations on the product, conventionally, a crystalline resin having a certain degree of elasticity at normal temperature and having high temperature cohesion is used for the polyester resin used for the adhesive layer. For example, Patent Document 1 discloses an adhesive composition containing at least one of a saturated copolymer polyester having a high melting point and a low melting point. However, even in the use of such a crystalline material, there are many processing restrictions such as temporary bonding for positioning before thermal bonding cannot be performed unless heating is performed at a temperature exceeding the melting point.
In recent years, it has been studied to increase mass production and reduce product costs by improving production speed, but sufficient adhesive strength cannot be obtained due to insufficient temperature during thermal bonding due to high speed. There was also a problem that the production speed had reached its peak.

Japanese Patent Laid-Open No. 2002-80813

  The present invention has been made to solve the above-mentioned problems, and is excellent in adhesiveness at low temperatures while maintaining adhesiveness at room temperature or high temperature, and excellent in temporary adhesion before thermal bonding of products during processing, An object is to provide a laminated film with an adhesive for electrical materials having high mass productivity.

The present invention is as follows.
(1) A laminated film with an adhesive for electrical materials, comprising a base material made of a plastic film, and at least one adhesive layer provided on at least one surface of the base material, wherein at least one of the adhesive layers A laminated film with an adhesive for electrical materials, wherein the surface layer contains a polyester-based hot melt adhesive containing a crystalline polyester resin and an amorphous polyester resin in a mass ratio of 80:20 to 99: 1. .

(2) A method for producing a laminated film with an adhesive for electrical materials, wherein at least one adhesive layer is provided on at least one surface of a substrate, wherein a crystalline polyester resin is used as a surface layer of the adhesive layer The manufacturing method of the laminated | multilayer film with an adhesive agent for electrical materials using the polyester type hot-melt-type adhesive agent which contains an amorphous polyester-type resin in the ratio of 80: 20-99: 1 by mass ratio.

  The laminated film with an adhesive for electrical materials of the present invention has excellent low-temperature temporary adhesiveness while maintaining adhesiveness at room temperature or high temperature. Therefore, temporary bonding at a temperature lower than the heat bonding temperature is possible, handling properties during processing are improved, and a laminated film with an adhesive for electrical materials excellent in mass production, specifically, a base film for flat cables is obtained. be able to.

The present invention is described in detail below.
The present invention is a laminated film with an adhesive for electrical materials, comprising a base material made of a plastic film, and at least one adhesive layer provided on at least one surface of the base material. Laminate with adhesive for electrical materials containing at least a polyester-based hot melt adhesive containing at least a surface layer containing a crystalline polyester resin and an amorphous polyester resin in a mass ratio of 80:20 to 99: 1 Related to film.

In the present invention, the polyertel-based hot melt adhesive used for the surface layer of the adhesive layer contains, as a main component, a polyester hot-melt resin which is a polycondensation polymer of dibasic acid and glycol.
Specific examples of dibasic acids used as raw material monomers for polyester hot melt resins include terephthalic acid, isophthalic acid, succinic acid, adipic acid, sebacic acid, dodecanedioic acid and the like. Specific examples of glycol include ethylene. Examples include glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, cyclohexanediol, and polyoxylene glycol. In the present invention, a hot melt resin made of a polyester resin containing adipic acid, 1,4-butanediol or the like in the molecular skeleton is preferably used.

The polyester hot melt adhesive in the present invention contains a crystalline polyester resin and an amorphous polyester resin as the polyester hot melt resin.
The crystalline polyester resin preferably has a melting point (Tm) in the range of 95 ° C to 130 ° C, more preferably 100 to 120 ° C, from the viewpoint of adhesiveness at high temperatures. The glass transition temperature (Tg) is preferably in the range of 25 to -60 ° C, more preferably 0 to -40 ° C for the reason of adhesiveness. Moreover, it is preferable that the molecular weight exists in the range of 15,000-20,000 by a mass mean molecular weight from the point of heat-and-moisture resistance.

  Specific examples of the crystalline polyester resin include, for example, trade names manufactured by Toyobo Co., Ltd., “Byron GM900” (Tm: 112 ° C., Tg: −15 ° C.), “Byron GM920” (Tm: 107 ° C.). , Tg: −35 ° C.), “Byron GM990” (Tm: 110 ° C., Tg: 0 ° C.), “Byron GM995” (Tm: 116 ° C., Tg: −2 ° C.), trade names of Toa Gosei Co., Ltd. “Aron Melt PES111” (Tm: 108 ° C., Tg: 0 ° C.), “PES111EE” (Tm: 107 ° C., Tg: 5 ° C.), “Aron Melt PES120E” (Tm: 125 ° C., Tg: −5 ° C.), “Aron Melt Commercially available products such as “PES120H” (Tm: 120 ° C., Tg: −10 ° C.) and trade name “Chemit R248” (Tm: 23 ° C., Tg: 113 ° C.) manufactured by Toray Industries, Inc. are used. Door can be. In the present invention, one kind of the above-mentioned resin may be used as the crystalline polyester resin, but a plurality of resins may be used in combination.

Moreover, as said amorphous polyester-type resin, that whose glass transition temperature is the range of 25-90 degreeC and also 40-75 degreeC is preferable from the point of the temporary-bonding process at 100 degrees C or less. Moreover, it is preferable that the molecular weight exists in the range of 3,500-25,000 in terms of a mass average molecular weight from the point of a low temperature adhesion process.
Specific examples of the amorphous polyester resin component include, for example, trade names “Byron 103” (Tg: 47 ° C.), “Byron 200” (Tg: 67 ° C.), and “Byron 600” manufactured by Toyobo Co., Ltd. ”(Tg: 47 ° C.),“ Elitel UE3200 ”(Tg: 65 ° C.),“ Elitel UE3210 ”(Tg: 45 ° C.) manufactured by Unitika Ltd. can be used. In the present invention, one kind of the above resin may be used as the amorphous polyester resin, but a plurality of resins may be used in combination.

In the laminated film of the present invention, the polyester hot melt adhesive contains the crystalline polyester resin and the amorphous polyester resin in a mass ratio of 80:20 to 99: 1. Specifically, it can be easily obtained by polymer blending each of the above resin materials, and considering the heat resistance of the adhesive and the like, it is preferable that there is less amorphous polyester resin, More preferably, the amorphous polyester resin is about 5 to 10% by mass with respect to the total amount of the crystalline polyester resin and the amorphous polyester resin.
The crystalline polyester resin and the amorphous polyester resin are preferably contained in the adhesive layer in an amount of 70 to 99% by mass from the viewpoint of sufficiently achieving the effects of the present invention.

The adhesive layer containing the polyester hot melt adhesive may contain a polyolefin resin, an epoxy resin, a hydrolysis inhibitor and the like from the viewpoint of processability and functionality.
Examples of the polyolefin resin include high density polyethylene, low density polyethylene, ultra low density polyethylene, linear low density polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-acetic acid. Vinyl-maleic anhydride terpolymer, ethylene-ethyl acrylate-maleic anhydride terpolymer, ethylene-glycidyl methacrylate copolymer, ethylene-vinyl acetate-glycidyl methacrylate terpolymer, ethylene -Ethyl acrylate-glycidyl methacrylate terpolymer can be used alone or in combination of two or more. These polyolefin resins can be added as, for example, a stress relaxation agent or a crystallization accelerator. Moreover, what gave adhesive functions, such as an acid modified material, can also be used for the said adhesive bond layer as polyolefin resin.

As the epoxy resin, a resin such as bisphenol A type or novolac type can be used. However, from the viewpoint of compatibility and adhesiveness, a bisphenol A type resin having a softening point of around 100 ° C. may be used. preferable.
The epoxy resin is effective for metal adhesion, and can improve the adhesion strength to metal with a slight addition depending on the application.
In addition, additives that are usually transferred, such as flame retardants, pigments, and dyes, can also be used in the adhesive layer.

It is preferable from the point of workability that the said polyester-type hot-melt-type adhesive agent shows moderate fluidity in the case of a process. From the above viewpoint, the melt viscosity of the polyester-based hot melt adhesive is a value measured by a Koka flow tester at a measurement temperature of 160 ° C. and a shear rate of 10 sec ⁻¹ , and is 300 to 5000 Pa · s, more preferably 2000 to 5000 Pa · s. Those within the range are preferred. If the adhesive has a melt viscosity of 300 Pa · s or more, the adhesive does not protrude from the plastic film serving as the substrate when heated and pressed, so there is no risk of trouble occurring during production. In addition, if the melt viscosity is 5000 Pa · s or less, the fluidity is sufficient, so that problems such as the formation of voids between the covering and the laminated film do not occur.

The adhesive layer in the laminated film of the present invention may be composed of one layer, but may be composed of a plurality of layers such as two layers and three layers. In the case of a plurality of layers, it is sufficient that at least the surface layer thereof is made of the polyester-based hot melt adhesive, but any other layer may also be made of the polyester-based hot melt adhesive. .
Although there is no restriction | limiting in particular about the thickness of an adhesive bond layer, In this invention, when considering the thickness of the target object to which a base material and a laminated film are applied, 0.1-2. It is preferably within a range of 0 times.

  In the laminated film of the present invention, examples of the plastic film constituting the substrate include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polymethylpentene (for example, trade name “TPX” manufactured by Mitsui Petrochemical Industries, Ltd.). ), Stretched polypropylene (OPP), unstretched polypropylene (CPP), and the like. However, from the viewpoint of mechanical strength and heat resistance, polyethylene terephthalate (PET) or polyethylene naphthalate (PEN) is used. Particularly preferred is a biaxially stretched PET film or a biaxially stretched PEN film.

Moreover, as a base material, what gave the printing process to the surface at the side which provides an adhesive bond layer can be used, and in such a case, compared with using a colored layer for an adhesive bond layer, it is a heat bonding processing machine. It is possible to prevent the color transfer of the colorant from occurring along with the adhesion of the adhesive to the heating laminating part.
In the present invention, the thickness of the substrate is not particularly limited, but is preferably in the range of, for example, 12 to 250 μm from the viewpoint of substrate strength and handling.
In the present invention, the term “film” or “sheet” includes both a film and a sheet.

Below, the manufacturing method of the laminated | multilayer film with an adhesive agent for electrical materials of this invention is demonstrated.
The laminated film of the present invention is one in which at least one adhesive layer is provided on the substrate. As a method for providing an adhesive layer on a substrate, there are a so-called solvent coating method in which a resin or the like is dispersed in a solvent and applied on the substrate, and a so-called solventless coating method in which no solvent is interposed. However, in the present invention, it is preferably produced by a solvent-free coating method from the viewpoint of mass productivity.

  A normal coating method can be applied to the solventless coating method, and any coating method may be determined in accordance with the melt viscosity or thermal stability of the adhesive. For example, each material of the adhesive is kneaded uniformly with an extruder, kneader, etc., then cooled once, further reheated with a hot melt applicator, etc., and kneaded uniformly with a lip coater, etc., and simultaneously with the substrate For example, a coating method can be used.

  Lamination of the adhesive layer can also be carried out by repeatedly performing the above steps, but after each material of the adhesive is uniformly kneaded to form a film, the film membrane and the substrate are combined. A laminated film can also be formed by bonding. Further, a plurality of extruders may be used in combination, and the resin melted and kneaded from each extruder may be formed into a film after the layers are combined using a feed block device. The bonding between the adhesive layer and the base material can be performed by, for example, thermocompression bonding using a laminate or a hot press.

  In order to improve the adhesion between the base material and the adhesive layer, the surface of the base material on the side of the adhesive layer may be subjected to corona discharge treatment, and an anchor coat layer may be provided on the base material. Examples of the adhesive for anchor coat used in the anchor coat layer include adhesives such as polyester, polyurethane, acrylic yarn, PVC-vinyl acetate copolymer system. In addition, a roll coat method, a gravure coat method or the like is preferably used for applying the anchor coat adhesive.

  In the present invention, the anchor coat layer can also be formed by laminating the anchor coat adhesive layer before stretching the substrate and stretching the substrate and the anchor coat adhesive layer simultaneously. In general, the thickness of the anchor coat layer is preferably in the range of about 0.1 to 5 μm.

EXAMPLES The present invention will be specifically described below using examples, but the present invention is not limited to these.
In addition, the glass transition temperature and melting | fusing point of the polyester type hot melt resin used in an Example etc. were measured as follows.

Measurement of glass transition temperature (Tg) and melting point (Tm) The glass transition temperature (Tg) and melting point (Tm) of a polyester hot melt resin were measured using a differential scanning calorimeter (trade name: PYRIS1-DSC, manufactured by PerkinElmer). Measurement was performed at a temperature of −60 ° C. to 200 ° C. and a scanning speed of 10 ° C./min.

Example 1
As an adhesive component of the adhesive layer, “Byron GM990” (Toyobo Co., Ltd.) is a crystalline polyester hot melt resin having a glass transition temperature (Tg) of 0 ° C. and a melting point (Tm) of 110 ° C. as shown in Table 1. Co., Ltd.) and “Byron GM990” (Toyobo Co., Ltd.), an amorphous polyester hot melt adhesive with a Tg of 67 ° C., pre-blended at a blending ratio of 90:10. Was put into a co-directional twin-screw extruder set to a temperature of 180 ° C. so that the temperature of the resin coming out of the die was 180 ° C., melted and kneaded, extruded into a sheet, cooled with a cast roll, and then 50 μm thick. An adhesive layer film was prepared.

A laminator in which a base material (100 μm thick biaxially stretched polyethylene terephthalate (PET) film) coated with a polyurethane anchor coat and the formed adhesive layer film is set at a temperature 20 ° C. higher than the melting point of the adhesive. A laminated film having an adhesive layer on a substrate was prepared by laminating using a roll.
In order to apply frost to the adhesive surface of the laminated film, the surface frost was transferred to the adhesive surface with a frosted cooling roll after the heat lamination and before the resin solidified.
The obtained laminated film was evaluated as follows. The results are shown in Table 2.

(1) Low-temperature temporary adhesive property The adhesive layer of the obtained laminated film is stacked so as to face an untreated stretched PET film (thickness 100 μm), one is a heated metal roll, and the other is It is sandwiched between a set of rolls (metal roll / rubber roll) consisting of unheated rubber rolls, and bonded under the condition that the roll nip pressure is 10 kg / cm (linear pressure) and the bonding speed is 0.5 m / min. Sample 1 for evaluation was created. However, the temporary bonding temperature for bonding was set to 80 ° C. in consideration of the use conditions.

Cut the prepared sample for evaluation 1 into a width of 10 mm, fix the untreated stretched PET film surface bonded together, and apply a load to the laminated film surface with an adhesive so as to be in a T-type peeled state, Peel evaluation was performed.
The measurement results were evaluated based on the criteria shown below. If the measured value is 300 g or more, there is no practical problem.
Evaluation criteria: (Peel resistance)
1000g or more "A"
700g or more and less than 1000g "B"
300g or more, less than 700g "C"
Less than 300g "D"

(2) 23 ° C. Adhesiveness A set of two laminated films obtained by stacking two laminated films so that the adhesive layers face each other, one is a heated metal roll, and the other is a non-heated rubber roll. Sample 2 for evaluation was prepared by sandwiching between rolls (metal roll / rubber roll) and roll nip pressure of 10 kg / cm (linear pressure) and a bonding speed of 0.5 m / min. However, the bonding temperature was 20 ° C. higher than the melting point of the higher adhesive used.
The prepared sample 2 for evaluation was cut into a width of 10 mm, and this was peeled off using a tensile tester (material testing machine with constant temperature bath “201X”, manufactured by Intesco Corporation) in each atmosphere at 23 ° C. and 80 ° C. The film was peeled 180 degrees at a speed of 10 mm / min.

The measurement results were evaluated based on the criteria shown below. If the measured value is 500 g / cm or more under the peeling condition of 23 ° C., it is at a level that causes no practical problem.
Evaluation criteria:
1500g / cm or more, or cohesive failure, substrate failure "A"
1000g / cm or more and less than 1500g / cm "B"
500g / cm or more and less than 1000g / cm "C"
Less than 500 g / cm “D”

(3) Adhesion at 80 ° C. Measurement was performed in the same manner as ((2) Adhesion at 23 ° C.) except that the temperature at the time of peeling evaluation was 50 ° C. The measurement results were evaluated based on the criteria shown below. If the measured value is 300 g / cm or more under the peeling condition of 50 ° C., it is a level with no practical problem.
Evaluation criteria:
1000g / cm or more, or cohesive failure, substrate failure "A"
700g / cm or more and less than 1000g / cm "B"
300g / cm or more, less than 700g / cm "C"
Less than 300 g / cm “D”

Examples 2-5 and Comparative Examples 1-3
In Example 1, a laminated film was prepared in the same manner as in Example 1 except that the type of adhesive used for the adhesive layer was changed as shown in Table 1. Further, the obtained laminated film was evaluated in the same manner as in Example 1. The results are shown in Table 2.

  As is apparent from Table 2, the laminated films of Examples 1 to 5 are excellent in any of temporary adhesion, 23 ° C. adhesive, and 50 ° C. adhesive. That is, it can be seen that these laminated films have high performance that can be practically used in any evaluation.

  The laminated film of the present invention is a laminated film that is heat-bonded by laminating or hot pressing or the like, for example, a laminated film with an adhesive for electrical materials used to cover core wires such as electric wires for electric equipment and electronic equipment. Specifically, it can be suitably applied to a base film for a flat cable.

Claims (4)

  A laminated film with an adhesive for electrical materials having a substrate made of a plastic film and at least one adhesive layer provided on at least one surface of the substrate, wherein at least the surface layer of the adhesive layer is A laminated film with an adhesive for electrical materials containing a polyester-based hot-melt adhesive containing a crystalline polyester-based resin and an amorphous polyester-based resin in a mass ratio of 80:20 to 99: 1.   The laminated film with an adhesive for electrical materials according to claim 1, wherein the glass transition temperature of the amorphous polyester resin is in the range of 25C to 90C.   The adhesive for electrical materials according to claim 1 or 2, wherein the crystalline polyester resin has a melting point in the range of 95 ° C to 130 ° C, and the amorphous polyester resin has a glass transition temperature in the range of 40 ° C to 75 ° C. Laminated film with agent.   A method for producing a laminated film with an adhesive for electrical materials, wherein at least one adhesive layer is provided on at least one surface of a substrate, wherein a crystalline polyester resin and an amorphous material are used as a surface layer of the adhesive layer Laminated film with an adhesive for electrical materials, in which a polyester hot melt adhesive containing a polyester resin in a mass ratio of 80:20 to 99: 1 is provided on at least one surface of a substrate by a solvent-free coating method Manufacturing method.