JP2008024725A - Adhesive film, process for producing flat cable with the same and flat cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an adhesive film which not only has high flame retardancy, bonding strength, and flexibility but can impart high heat resistance to, e.g., a flat cable produced with this adhesive film, to provide a process for producing a flat cable with this adhesive film and to obtain a flat cable produced by the production process. <P>SOLUTION: The adhesive film is characterized in that it comprises an insulating resin base and an adhesive layer and that the adhesive layer comprises 100 parts by weight of a phosphorus-modified unsaturated polyester and 5-200 parts by weight of a phosphorus compound flame retardant and/or a nitrogenous compound flame retardant which each contains no halogens, the phosphorus-modified unsaturated polyester containing 0.2-2.7 wt.% phosphorus and having unsaturated groups introduced therein in an amount of 0.2-20 mmol per mol of the polybasic acid ingredient monomer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention has a high heat resistance and flame retardancy, and is produced by an adhesive film used as an insulating film for a flat cable, a flat cable manufacturing method using the adhesive film, and a manufacturing method thereof. It is related with the flat cable characterized by this.

  Flat cables used for internal wiring of various electric and electronic devices generally have a plurality of conductors arranged parallel to each other between insulating adhesive films (insulating films). Are bonded together by heat fusion or the like and integrated. An adhesive film used for manufacturing a flat cable is usually composed of an insulating resin base material having flexibility (softness) and excellent mechanical properties and electrical characteristics, and an adhesive layer. Adhesion between the adhesive films and between the adhesive film and the conductor is performed.

  Since the flat cable is sometimes used in a high temperature environment, the adhesive film for the flat cable is required to have excellent heat resistance and flame retardancy as well as excellent flexibility, mechanical properties, electrical properties, and adhesiveness. Conventionally, halogen flame retardants such as decabromodiphenyl ether (DBDPO) have been used for imparting flame retardancy. However, halogen-based flame retardants have problems such as the formation of dioxin-related substances during combustion, so from the viewpoint of environmental protection, use halogen-free flame retardants such as metal hydroxides and increase their filling amount. Thus, a method for obtaining a flame retardant effect was also employed. However, when the filling amount is increased, there are problems such as a decrease in adhesive strength and a decrease in flexibility of the adhesive film.

In order to solve the problem of the halogen-free flame retardant, an adhesive sheet (adhesive film) having an adhesive layer made of a phosphorus-modified saturated polyester copolymer in which a phosphorus component is introduced into the main skeleton of the saturated copolymer polyester And a flat cable using the adhesive sheet is proposed in Japanese Patent No. 2987831. Adhesive sheets using this phosphorus-modified saturated polyester copolymer not only exhibit high flame retardancy, but also exhibit excellent adhesive strength, and can greatly reduce the amount of flame retardants such as metal hydroxides used. There will be no decrease in However, this adhesive sheet has low heat resistance, and has problems such as a decrease in adhesive strength due to long-term use in a high-temperature environment and peeling of the adhesive layer.
Japanese Patent No. 2987831 (Claim 1)

  The present invention is a halogen-free adhesive film that can be used as an insulating film for a flat cable, which solves the problems of the prior art and exhibits high flame retardancy, adhesive strength, and flexibility. An adhesive film capable of giving high heat resistance that does not cause problems such as peeling even when used in a high temperature environment for a long time in a flat cable manufactured using the above, a method for manufacturing a flat cable using this adhesive film, and It aims at providing the flat cable manufactured by this manufacturing method.

  As a result of the study, the present inventor, when using a phosphorus-modified unsaturated polyester containing phosphorus and an unsaturated group in the adhesive layer, the phosphorus-modified unsaturated polyester is crosslinked by ionizing radiation irradiation or the like because it has an unsaturated group. As a result, the present inventors have found that heat resistance is improved, and problems such as peeling are less likely to occur even when used for a long time in a high temperature environment. By using phosphorus-modified unsaturated polyester, an adhesive film having high flame retardancy and adhesive strength can be obtained, the heat resistance of the flat cable can be improved, and the amount of flame retardant contained in the adhesive layer can be reduced. Therefore, the inventors have found that excellent flexibility can be maintained, and thus completed the present invention.

The present invention, as claim 1,
It consists of an insulating resin base material and an adhesive layer formed thereon,
The adhesive layer contains a phosphorus-modified unsaturated polyester and a halogen-free phosphorus-based flame retardant and / or a nitrogen-based flame retardant having a phosphorus concentration in the molecule of 5% by weight or more,
The phosphorus-modified unsaturated polyester contains 0.2 to 2.7% by weight of phosphorus with respect to its weight, and 0.2 to 20 mmol is introduced per mol of the polybasic acid component monomer constituting the unsaturated group. And a total content of the phosphorus flame retardant and the nitrogen flame retardant is 5 to 200 parts by weight with respect to 100 parts by weight of the phosphorus-modified unsaturated polyester. provide.

That is, the adhesive film of Claim 1 consists of the structure of 1) -6) shown next.
1) It consists of an insulating resin substrate and an adhesive layer formed thereon.
2) The adhesive layer contains a phosphorus-modified unsaturated polyester and a phosphorus-based flame retardant and / or a nitrogen-based flame retardant.
3) The phosphorus-modified unsaturated polyester contains 0.2 to 2.7% by weight of phosphorus with respect to its weight.
4) The phosphorus-modified unsaturated polyester is obtained by introducing an unsaturated group in an amount of 0.2 to 20 mmol per 1 mol of the constituting polybasic acid component monomer.
5) The phosphorus-based flame retardant is halogen-free and has a phosphorus concentration of 5% by weight or more.
6) The total content of the phosphorus-based flame retardant and the nitrogen-based flame retardant is 5 to 200 parts by weight with respect to 100 parts by weight of the phosphorus-modified unsaturated group polyester.

  The phosphorus-modified unsaturated polyester is a polyester in which an unsaturated group is introduced, and a phosphorus component is introduced into its main skeleton. The phosphorus-modified unsaturated polyester is a polybasic acid component containing an unsaturated polybasic acid or an anhydride thereof and a polyhydric alcohol, and if necessary, other monomers copolymerizable therewith (hereinafter referred to as a copolymerization component). ), And at least one of the polybasic acid component, the polyhydric alcohol, or the copolymer component needs to contain phosphorus (hereinafter, a component containing phosphorus is referred to as a phosphorus component). ).

  Examples of the unsaturated polybasic acid or anhydride thereof include maleic acid, fumaric acid, itaconic acid, citraconic acid, and the like, and anhydrides thereof such as maleic anhydride. Two or more of these may be used in combination. As the polybasic acid component, in addition to the unsaturated polybasic acid or its anhydride, a saturated polybasic acid or its anhydride usually adjusts the concentration of the unsaturated group, and also has flexibility, strength and heat resistance. It is used together from the viewpoint of characteristics such as sex. Here, examples of the saturated polybasic acid include terephthalic acid, naphthalenecarboxylic acid, adipic acid, sebacic acid, and isophthalic acid.

  As the phosphorus component, phosphonate type polyols or phosphate type polyols, phosphinate type polyols which are polyhydric alcohols, vinyl phosphonates or allyl phosphonates which are copolymerization components can be used. Thus, the polyester copolymer in which the phosphorus component is introduced into the main skeleton exhibits flame retardancy higher than that obtained by simply mixing and dispersing the phosphorus component in the polyester.

  Examples of polyhydric alcohols other than the phosphorus component include neopentyl glycol, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, 1,3-propanediol, 1,4-butanediol, and other aliphatic glycols, aromatic glycols, and fats. Examples thereof include trihydric or higher alcohols such as cyclic glycol, trimethylolpropane, pentaerythritol, and unsaturated polydiene polyol (for example, R-45HT manufactured by Idemitsu Petrochemical Co., Ltd.). Two or more of these may be used in combination.

  The phosphorus-modified unsaturated polyester was subjected to direct esterification or transesterification at a temperature of 200 to 280 ° C. under normal pressure using a copolymer component containing the polybasic acid component and the polyhydric alcohol and containing the phosphorus component. Then, it can manufacture by performing a melt polycondensation reaction at 200-280 degreeC under pressure reduction of 5 hPa or less in presence of a catalyst. As the catalyst, a conventionally known catalyst as described in paragraph 0019 of JP-A-2000-128967 is used.

  The phosphorus content (phosphorus concentration) in the phosphorus-modified unsaturated polyester depends on the type of polyester, the type of phosphorus component, the other components forming the adhesive layer or the type of insulating film constituting the adhesive sheet, etc. The adhesive film of the invention can be determined so as to satisfy a predetermined flame retardancy, but is at least 0.2% by weight and 2.7% by weight or less based on the weight of the phosphorus-modified unsaturated polyester.

  When the phosphorus concentration is less than 0.2% by weight, sufficient flame retardancy cannot be obtained. On the other hand, if it exceeds 2.7% by weight, it becomes difficult to increase the degree of polymerization, and the mechanical strength of the product is lowered. Adjustment of phosphorus concentration can be performed by adjusting the quantity of the phosphorus component in the monomer used for manufacture of phosphorus-modified unsaturated polyester, ie, the component containing phosphorus.

  The amount of unsaturated groups introduced in the phosphorus-modified unsaturated polyester is based on 1 mol of the polybasic acid component monomer (polybasic acid component in the monomer used for copolymerization) constituting the phosphorus-modified unsaturated polyester. It is 0.2 mmol or more (or 1 mol of polyhydric alcohol) and 20 mmol or less. When the amount of unsaturated groups introduced is less than 0.2 mmol, sufficient heat resistance cannot be obtained even when the phosphorus-modified unsaturated polyester is crosslinked by irradiation or the like. On the other hand, if it exceeds 20 mmol, the resin stability (solution stability) is lowered, and it becomes easy to form a gel during the production of the phosphorus-modified unsaturated polyester or when mixed with a flame retardant, and the thin film coating cannot be performed. As described above, the introduction amount of the unsaturated group can be adjusted by adjusting the ratio of the unsaturated polybasic acid or its anhydride in the polybasic acid component.

  The adhesive layer of the adhesive film of the present invention contains a phosphorus flame retardant and / or a nitrogen flame retardant together with the phosphorus-modified unsaturated polyester. That is, it contains at least one flame retardant selected from the group consisting of phosphorus-based flame retardants and nitrogen-based flame retardants, and when it contains only phosphorus-based flame retardants, In addition, both a phosphorus-based flame retardant and a nitrogen-based flame retardant may be contained. This phosphorus flame retardant is halogen-free and has a phosphorus concentration of 5% by weight or more based on the total amount of the phosphorus flame retardant. When the phosphorus concentration is less than 5% by weight, the effect of improving flame retardancy is not sufficient.

  Examples of such phosphorus flame retardants include phosphoric esters such as triphenyl phosphite and bisphenol A bis (diphenyl) phosphate, ammonium polyphosphate, and the like. Examples of nitrogen flame retardants include triazine flame retardants such as melamine cyanurate and melamine.

  The total content of the phosphorus-based flame retardant and the nitrogen-based flame retardant is in the range of 5 to 200 parts by weight with respect to 100 parts by weight of the phosphorus-modified unsaturated group polyester. When the amount is less than 5 parts by weight, sufficient flame retardancy cannot be obtained. On the other hand, when it exceeds 200 parts by weight, the flexibility of the adhesive film and the flat cable is lowered, and the adhesive force of the adhesive film is lowered, so that a sufficient adhesive force cannot be obtained.

  The adhesive film of the present invention, for example, applies a solution obtained by dissolving the phosphorus-modified unsaturated polyester and the phosphorus-based flame retardant and / or the nitrogen-based flame retardant in a solvent on an insulating resin base material, and dries the solvent. It is manufactured by. Solvents include aromatics such as benzene, toluene and xylene, esters such as ethyl acetate and γ-butyrolactone, ketones such as acetone and methyl ethyl ketone, ethers such as tetrahydrofuran and ethyl cellosolve, n-hexane and n-octane. Aliphatic hydrocarbons and the like such as these are exemplified, and one or more of these mixed solvents are used.

  The insulating resin base material is a resin film that is excellent in mechanical strength, heat resistance, flexibility, flexibility, chemical resistance, solvent resistance, insulation, etc. and does not contain halogen from the viewpoint of environmental protection. Preferably used. As such a resin, a resin having an aromatic ring in the molecular skeleton and containing no halogen is preferably exemplified. Claim 2 corresponds to this preferred embodiment, and is the adhesive film, wherein the insulating resin base material is a resin having an aromatic ring in a molecular skeleton and containing no halogen. An adhesive film is provided.

  More specifically, as a resin having an aromatic ring in the molecular skeleton and not containing a halogen, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyimide, Examples thereof include various resins such as polyamide-based resins such as polyamideimide and polyetherimide, polyphenylene sulfide and the like, and polyether ketones, polyester ethers, and polycarbonates having an aromatic ring. Among the exemplified resins, polyethylene terephthalate and polyethylene naphthalate are more preferable from the viewpoint of price.

  The thickness of the insulating resin base material is preferably about 9 μm to 100 μm, and the thickness of the adhesive layer is preferably about 10 μm to 100 μm.

  The said adhesive film of this invention is used for manufacture of a flat cable etc. as a coating | covering material (insulating film). For example, the flat cable uses two adhesive films of the present invention, sandwiches one or a plurality of conductors between the adhesive layers, and bonds the adhesive layers to create a cable. Then, it can manufacture by the method of bridge | crosslinking phosphorus modified unsaturated polyester. When the phosphorus-modified unsaturated polyester is crosslinked, the heat resistance of the flat cable is improved, and problems such as film peeling are less likely to occur even when used in a high temperature environment for a long time.

  Claim 3 corresponds to this embodiment, a conductor is sandwiched between the adhesive layers of the two adhesive films, the adhesive layers are bonded together, a cable is formed, and then the phosphorus-modified unsaturated polyester is crosslinked. The present invention provides a method of manufacturing a flat cable characterized in that it is performed.

  As a method for crosslinking the phosphorus-modified unsaturated polyester, a method of irradiating the cable with ionizing radiation is preferable because the amount of crosslinking can be easily adjusted by adjusting the amount of irradiation. Claim 4 corresponds to this preferred embodiment, and is a method for manufacturing the flat cable, wherein the cross-linking of the phosphorus-modified unsaturated polyester is performed by irradiating the cable with ionizing radiation. A method for manufacturing a cable is provided. Examples of the ionizing radiation include electron beams and γ rays.

It is preferable to set the irradiation amount of ionizing radiation to an amount such that the gel fraction becomes 5% by weight or more by crosslinking of the phosphorus-modified unsaturated polyester, because sufficient heat resistance of the flat cable can be obtained. Claim 5 corresponds to this preferable mode. Here, the gel fraction was determined by immersing the phosphorus-modified unsaturated polyester constituting the adhesive layer in a mixed solvent of toluene / methyl ethyl ketone (volume ratio 4/1) at 60 ° C. for 24 hours, without dissolving. The remaining residue was dried at 80 ° C., weighed, and obtained by the following formula.
Gel fraction (% by weight) = {(weight of residue after drying) / (weight before dissolution)} × 100

  According to a sixth aspect of the present invention, there is provided a flat cable manufactured by the method for manufacturing a flat cable according to the present invention. This flat cable has high flame resistance, adhesive strength and flexibility, has high heat resistance, and does not cause problems such as a decrease in adhesive strength even when used for a long time in a high temperature environment. It is suitably used for internal wiring of various electric and electronic devices.

  The adhesive film of the present invention is halogen-free and exhibits high flame retardancy, adhesive strength and flexibility, and can be used for a long time in a high-temperature environment, such as a flat cable manufactured using this adhesive film. High heat resistance that does not cause problems such as peeling can be provided. According to the method for producing a flat cable of the present invention, which is characterized by bonding two sheets of the adhesive film of the present invention and a conductor, and crosslinking the phosphorus-modified unsaturated polyester. A flat cable that has flexibility and high heat resistance and does not cause problems such as peeling even when used in a high temperature environment for a long time can be obtained. The flat cable obtained by this manufacturing method has the above-mentioned excellent characteristics, and is suitably used for internal wiring of various electric and electronic devices.

  Next, the best mode for carrying out the present invention will be described as an example. In addition, this invention is not limited to this Example, The change to another form is also possible unless the meaning of this invention is impaired.

Production Example Production of Phosphorus-Modified Unsaturated Polyester A mixture of 481.4 g of terephthalic acid, 288.8 g of isophthalic acid, 222.6 g of sebacic acid and 6.73 g of fumaric acid as a polybasic acid component , 4-butanediol (570.8 g), neopentyl glycol (206.1 g) and phosphorus-containing glycol (trade name: PE-100, manufactured by Clariant) (35.5 g) were used, and the catalyst tetrabutyl titanate was added at a concentration. Was added at 300 ppm and esterification was carried out at 230 ° C. for 2 hours. Thereafter, the same amount of catalyst was added, the pressure was reduced to 2 hPa, and the polycondensation reaction was carried out for 2 hours. Then, a mixed solvent of toluene / methyl ethyl ketone (volume ratio 4/1) was added, and the phosphorus-modified unsaturated polyester was 30% by weight. A dissolved toluene / methyl ethyl ketone solution was obtained. This is designated as phosphorus-modified unsaturated polyester 1. The phosphorus concentration in the phosphorus-modified unsaturated polyester 1 was 0.3% by weight, and the amount of unsaturated groups introduced was 10 mmol with respect to 1 mol of the acid component of the raw material monomer. The phosphorus concentration and the amount of unsaturated groups introduced were measured by NMR.

  Phosphorus-modified unsaturated polyester 2 in the same manner as described above except that the phosphorus concentration and the amount of unsaturated groups introduced were changed by changing the ratio of raw material monomers, 1,4-butanediol, neopentyl glycol and phosphorus-containing glycol. ~ 9 was obtained. Table 1 shows the phosphorus concentration and the amount of unsaturated groups introduced.

Preparation of adhesive film Phosphorus flame retardant (trade name: PX-200, manufactured by Daihachi Chemical Industry Co., Ltd.) to each of the toluene / methyl ethyl ketone (volume ratio 4/1) solutions of the above phosphorus-modified unsaturated polyesters 1 to 9 A liquid obtained by mixing a flame retardant having a C—O bond, phosphorus content: 9% by weight) and melamine cyanurate in the mixing ratios shown in Tables 2 and 3 was obtained as a polyethylene terephthalate film (trade name). : Lumirror, manufactured by Toray Industries, Inc., having a thickness of 25 μm), and the solvent was dried to prepare an adhesive film. At that time, the thickness of the adhesive layer on the polyethylene terephthalate film was 40 μm.

Preparation of cable Two sheets of the adhesive film obtained above were used. Ten tin-plated annealed copper foils (thickness 0.035 mm x width 0.8 mm) are arranged in parallel on one adhesive layer, and then the other adhesive film is placed so that the adhesive layers face each other. Then, they were laminated and thermocompression bonded to form a flat cable. Thereafter, the flat cable was irradiated with γ rays (50 kGy) to crosslink the phosphorus-modified unsaturated polyester. The gel fraction of the phosphorus-modified unsaturated polyester after crosslinking was measured and found to be 50% by weight.

  Each of the thus obtained flat cables after γ-irradiation was evaluated for flame retardancy, adhesive strength, heat resistance, and solution stability.

  Flame retardancy was evaluated by the vertical combustion test (UL1581). Those that extinguish in 60 seconds or less were considered acceptable. The adhesive strength was determined by measuring the adhesive strength with the annealed copper foil by a 180 ° peeling method, and setting 0.5N or more as acceptable. As for heat resistance, the sample was allowed to stand at 113 ° C. for 1 week, and the adhesive layer did not cause delamination (peeling). The solution stability was determined to be acceptable when the phosphorus-modified unsaturated polyester was polymerized or when the flame retardant was mixed. These results are shown in Tables 2 and 3.

  From the results of Tables 2 and 3, it is clear that in Examples 1 to 6 within the scope of the present invention, all evaluation items of flame retardancy, adhesive strength, heat resistance, and solution stability are excellent.

On the other hand, in Comparative Example 1 using the phosphorus-modified unsaturated polyester 5 having a phosphorus concentration of less than 0.2% by weight (0.1% by weight), the flame retardancy is low. Comparative Example 2 using phosphorus-modified unsaturated polyester 6 having a phosphorus concentration exceeding 2.7 wt% (3.0 wt%), and phosphorus-modified unsaturated polyester 7 having an introduction amount of unsaturated groups exceeding 20 mmol (25 mmol) In Comparative Example 3 using the solution, the solution stability is low. On the other hand, Comparative Example 4 using the phosphorus-modified unsaturated polyester 8 having an introduction amount of unsaturated groups of less than 0.2 mmol (0.1 mmol) has low heat resistance. In Comparative Example 5 and Comparative Example 6 in which the total amount of the phosphorus-based flame retardant and the nitrogen-based flame retardant exceeds 200 parts by weight, the adhesive strength is low.

Claims (6)

It consists of an insulating resin base material and an adhesive layer formed thereon,
The adhesive layer contains a phosphorus-modified unsaturated polyester and a halogen-free phosphorus-based flame retardant and / or a nitrogen-based flame retardant having a phosphorus concentration in the molecule of 5% by weight or more,
The phosphorus-modified unsaturated polyester contains 0.2 to 2.7% by weight of phosphorus with respect to its weight, and 0.2 to 20 mmol is introduced per mol of the polybasic acid component monomer constituting the unsaturated group. And the total content of the phosphorus-based flame retardant and the nitrogen-based flame retardant is 5 to 200 parts by weight with respect to 100 parts by weight of the phosphorus-modified unsaturated group polyester.   The adhesive film according to claim 1, wherein the insulating resin base material is a resin having an aromatic ring in a molecular skeleton and containing no halogen.   A conductor is sandwiched between the adhesive layers of the two adhesive films according to claim 1 or 2, and the adhesive layers are bonded together to form a cable, followed by crosslinking of the phosphorus-modified unsaturated polyester. The manufacturing method of the flat cable.   The method for producing a flat cable according to claim 3, wherein the cross-linking of the phosphorus-modified unsaturated polyester is performed by irradiating the cable with ionizing radiation.   6. The method for producing a flat cable according to claim 5, wherein the irradiation amount of ionizing radiation is such that the gel fraction becomes 5% by weight or more due to crosslinking of the phosphorus-modified unsaturated polyester. A flat cable manufactured by the method for manufacturing a flat cable according to any one of claims 3 to 5.