JP2000080342A - Fire retardant adhesive, and fire retardant adhesion film and flat cable using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve fire retardant, electrical insulating properties and adhesion properties of a fire retardant adhesion film and a flate cable by comprising a polyester series resin, a nitrogen-containing organic fire retardant and a boron compound. SOLUTION: This fire retardant adhesive is obtained by reacting an acid component of terephthalic acid, isophthalic acid, polyvalent carboxylic acid having a phosphoric acid residue in a molecule or the like with a dialcohol component of ethylene glycol, 1,4-butanediol or the like to prepare a phosphorus interfilled polyester series resin having a phosphoric acid residue in a molecule, said polyester series resin having number average molecular weight of 3,000-100,000, preferably 10,000-50,000 and glass transion point of 0-100 deg.C, preferably 0-70 deg.C, and compounding 100 pts.wt. of the sum of the polyester series resin of 100 pts.wt. and a nitrogen-containing organic fire retardant of 50-150 pts.wt., preferably 50-100 pts.wt., and a boron compound of 5-150 pts.wt., preferably 10-100 pts.wt. A fire retardant adhesion film is obtained by coating the fire retardant adhesive so as to be 10-100 μm thick on an insulating base film of a few μm-several hundreds μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a flame-retardant adhesive containing a halogen-free flame retardant and having excellent insulating properties, a flame-retardant adhesive film using the same, and a flat cable.

[0002]

2. Description of the Related Art A flat cable having a structure in which a plurality of linear conductors are covered with two adhesive films each having an adhesive layer formed on a base film is known. Such a flat cable is widely used in recent years for wiring high-density mounted AV equipment and computer equipment.

By the way, for a flat cable,
From the viewpoints of electrical use and disaster prevention, it is desired that constituent materials other than conductors (that is, an adhesive film composed of a base film and an adhesive layer) exhibit good insulating properties and flame retardancy.

[0004] For this reason, the adhesive layer of the adhesive film used for the flat cable is conventionally coated with a halogen-based flame retardant (for example, decabromodiphenyl ether or hexabromodiphenyl ether) or silica or clay as a flame retardant auxiliary. And an inorganic filler such as an antimony compound. However, due to recent consideration for global environmental protection, non-halogen flame retardants have been used as flame retardants to be added to the adhesive layer instead of halogen flame retardants. For example, JP-A-6-338225 discloses that a non-halogen flame retardant such as red phosphorus, a phosphoric ester or magnesium hydroxide is added to a polyester flame retardant layer of an adhesive tape for a flat cable.
Further, Japanese Patent Application Laid-Open No. 9-221642 discloses a thermoplastic polyester resin base material constituting an adhesive film for a flat cable or an adhesive layer formed thereon.
It is disclosed that the compound is made flame-retardant by a phosphorus-based flame retardant.

[0005]

When a flat cable is used as a wiring for various products related to human body safety (for example, airbags of automobiles and medical equipment), it is very difficult to secure safety stably. High insulation properties (specifically, at least 10 ¹⁰ Ω) is required.

However, in the case of the adhesive tape or the adhesive film disclosed in the above-mentioned publication, the electric resistance of the adhesive tape or the adhesive film is made sufficiently high due to the moisture absorption or ionicity of the non-halogen flame retardant used. There is a problem that you can not. Further, the non-halogen flame retardant as described above has essentially insufficient flame retardancy as compared with the conventional halogen flame retardant, and in order to realize a desired insulating property, an adhesive layer of the non-halogen flame retardant is required. It is necessary to increase the content in the, the adhesive force of the adhesive layer is reduced,
When the flat cable is manufactured, the adhesive layer and the conductor are easily separated from each other, and the cohesive force of the adhesive layer is reduced.

[0007] The present invention is to solve the problems of the prior art, using a non-halogen flame retardant, a flame-retardant adhesive or a flame-retardant adhesive film suitable for flat cable production. It is an object of the present invention to achieve flame retardancy comparable to halogen-based flame retardants while maintaining good electrical insulation and adhesion.

[0008]

DISCLOSURE OF THE INVENTION The present inventors have used a polyester resin having relatively low hygroscopicity as a base resin for a flame-retardant adhesive, and used a nitrogen-containing organic flame retardant such as melamine as a flame retardant. It has been found that the above-mentioned object can be achieved by using the compound of the formula (1) and a boron compound as a flame retardant auxiliary, and has completed the present invention.

That is, the present invention provides the following component (A):
(B) and (C): A flame-retardant adhesive comprising: (A) a polyester resin; (B) a nitrogen-containing organic flame retardant; and (C) a boron compound.

Further, the present invention provides a flame-retardant adhesive film characterized in that a flame-retardant adhesive layer comprising the flame-retardant adhesive is provided on an insulating base film.

Further, the present invention provides a flat cable characterized in that an electric conductor is covered with the flame-retardant adhesive film.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The flame-retardant adhesive of the present invention comprises the following components (A), (B) and (C): (A) a polyester resin; (B) a nitrogen-containing organic flame retardant; and (C) a boron compound. It contains.

In the flame-retardant adhesive of the present invention, the polyester resin as the component (A) is both an adhesive component and a film-forming component. The reason for choosing polyester resin is
This is because it has relatively low hygroscopicity as compared with a polyamide resin or the like generally used as an adhesive component, has no practical problem in film strength, and is excellent in electrical insulation.

As such a polyester resin,
An acid component (for example, terephthalic acid, isophthalic acid, diphenyldicarboxylic acid, adipic acid, sebacic acid, a polycarboxylic acid having a phosphoric acid residue in the molecule, glutaric acid, trimellitic acid, sodium sulfoisophthalate, etc.), A dialcohol component (eg, ethylene glycol, 1,4
-Butanediol, 1,4-dicyclohexane dimethanol, 1,4-cyclohexane dimethylol, diethylene glycol, ethylene oxide addition of bisphenol A trimethylolpropanol, etc.). Among them, a phosphorus-containing polyester resin having a phosphoric acid residue in the molecule (Japanese Patent Application Laid-Open No. H8-60108) is preferred in terms of high flame retardancy.

The number average molecular weight of the polyester resin of the component (A) is based on the case where the flame retardant adhesive contains a large amount of the nitrogen-containing organic flame retardant of the component (B) and the boron compound of the component (C) described later. From the viewpoint of ensuring a sufficient film-forming property even if it is present, it is preferably in the range of 3,000 to 100,000, more preferably 10,000 to 50,000.

The glass transition point of the polyester resin of the component (A) is preferably 0 so that when the flame-retardant adhesive is applied to the production of a flat cable, it can be satisfactorily thermally bonded to a linear conductor. ~ 100 ° C, more preferably 0 ~
70 ° C.

The nitrogen-containing organic flame retardant of the component (B) is a halogen-free flame retardant and increases the electric resistance when incorporated in a flame-retardant adhesive. Examples of the nitrogen-containing organic flame retardant of component (B) include melamine (cyanuric acid triamide), ammeline (cyanuric acid diamide), ammelide (cyanuric acid monoamide), melam ([3,5-
(NH ₂ ) C ₃ N ₃ ] NH), melamine cyanurate (condensation of melamine and cyanuric acid), melamine resin, melamine derivatives such as homoguanamine, benzoguanamine, and acetoguanamine. . Among these, dispersibility in polyester resin,
Melamine, melamine cyanurate or benzoguanamine can be preferably used from the viewpoints of mixing properties, adhesiveness and the like.

When the amount of the nitrogen-containing organic flame retardant of the component (B) is too small, a sufficient flame-retarding effect cannot be obtained, and when it is too large, the adhesive strength becomes insufficient. 50 to 150 parts by weight per 100 parts by weight of resin
Parts by weight, more preferably 50 to 100 parts by weight.

The boron compound of the component (C) comprises the component (B)
When used in combination with a nitrogen-containing organic flame retardant, it is used as a flame retardant auxiliary agent that achieves good flame retardancy and good adhesion in a flame retardant adhesive. Examples of such a boron compound include manganese borate, zinc borate, ammonium borate, lead borate and the like. Among them,
Zinc borate and manganese borate can be preferably used from the viewpoint of flame retardancy.

When the amount of the boron compound (C) is too small, the effect of addition is not sufficiently obtained, and when the amount is too large, the adhesiveness is reduced. Therefore, the polyester resin of the component (A) and the component (B) 5 to 150 parts by weight, more preferably 1 to 100 parts by weight of the total nitrogen-containing organic flame retardant of the present invention.
0 to 100 parts by weight.

The flame-retardant adhesive of the present invention contains various additives such as an organic solvent, an antioxidant, a metal corrosion inhibitor, and a coloring agent (pigment, pigment, etc.) as long as the effects of the present invention are not impaired.
Dyes), various coupling agents that increase the cohesive force between the adhesive component resin and the flame retardant, crosslinking agents, crosslinking aids, fillers,
An antistatic agent, a flame retardant catalyst, a phosphorus-based flame retardant, and the like may be appropriately added.

The flame-retardant adhesive of the present invention can be produced by uniformly mixing the components (A) to (C) and, if necessary, other additives.

The flame-retardant adhesive of the present invention can be used in the form of a solution, paste, pellet or the like.

Next, the flame-retardant adhesive film of the present invention will be described.

The flame-retardant adhesive film of the present invention has a structure in which a flame-retardant adhesive layer comprising the above-mentioned flame-retardant adhesive is provided on an insulating base film. Therefore, this flame-retardant adhesive film is a flame-retardant adhesive film capable of realizing flame retardancy comparable to halogen-based flame retardants while maintaining good electrical insulation and adhesiveness.

The thickness of the flame-retardant adhesive layer varies depending on the purpose of use of the flame-retardant adhesive film and the like.
It is.

Examples of the insulating base film include polyethylene terephthalate film, polyethylene naphthalate film, polyimide film, polyphenylene sulfide film, polypropylene oxide film, polyethylene film, polypropylene film, polyamide film and the like. Further, the thickness can be appropriately selected according to the purpose of use, and can be, for example, several μm to several hundred μm.

The flame-retardant adhesive film of the present invention is prepared by applying a solution containing the above-mentioned flame-retardant adhesive of the present invention containing an organic solvent (for example, toluene) onto an insulating substrate film such as polyethylene terephthalate and drying. It can be manufactured by forming a flame-resistant adhesive layer or by melt-extruding and forming a flame-retardant adhesive on an insulating substrate film.

The flame-retardant adhesive film of the present invention can be used as a surface protection film for various circuits.
Particularly, it can be preferably used when producing a flat cable. For example, a flat cable can be manufactured by arranging a plurality of conductors in parallel and then laminating a flame-retardant adhesive film from above and below the conductors. Here, the flame-retardant adhesive film has insufficient tackiness at room temperature due to the presence of the flame retardant.
It can be produced by a heat lamination method using a roll heated to a temperature of 0 ° C.

[0031]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples.

Examples 1 to 7 and Comparative Examples 1 to 4 (Preparation of Flame Retardant Adhesive)
Polyester resin (Elitel series (saturated polyester resin), manufactured by Unitika) is dissolved in a mixed solvent consisting of 75 parts by weight of methyl ethyl ketone and 300 parts by weight of toluene, and a flame retardant and a flame retardant auxiliary are added to the solution. The mixture was stirred to prepare a flame-retardant adhesive in the form of a solution.

(Preparation of Flame-Retardant Adhesive Film) A flame-retardant adhesive in the form of a solution was applied to a 25 μm-thick polyester film (manufactured by Unitika) using a bar coater, and then put into a drying oven to add methyl ethyl ketone and toluene. It was volatilized to form a flame-retardant adhesive layer (40 μm thick). Thus, a flame-retardant adhesive film was obtained.

(Preparation of Flat Cable) Two pieces of the obtained flame-retardant adhesive film cut to a predetermined length are prepared, and a plurality of rectangular conductors having a wire thickness of 50 μm are formed on one flame-retardant adhesive film. (Tin-plated flat copper wire) are placed side by side in parallel, and the other flame-retardant adhesive film is placed on it, and then passed between two rolls heated to 150 ° C. The films were laminated to produce a flat cable.

(Evaluation) Regarding the flame-retardant adhesives of Examples 1 to 7 and Comparative Examples 1 to 4, as described below, “electric resistance”, “flame retardancy and combustion gas”, and “adhesion” were used. Was evaluated. The obtained results are shown in Tables 1 and 2.

(Electrical Resistance) The electrical resistance between the adjacent conductors (conductor length 100 mm) of the flat cable (applied voltage 0. 1).
5 KV). The case where the electric resistance exceeds 10 ¹¹ Ω was evaluated as “○”, and the electric resistance was 10 ¹⁰ Ω or more and 10 ¹¹ Ω or more.
The case where the resistance was less than Ω was evaluated as “Δ”, and the case where the electric resistance was less than 10 ¹⁰ Ω was evaluated as “×”.

Here, when the flat cable is applied to automobile parts, medical equipment and the like which require high safety, an electric resistance of 10 ¹⁰ Ω or more is required.

(Flame Retardant and Combustion Gas) UL-SUB75
A flame retardancy test was performed by a method based on 8-VW1. Here, the case where the flame retardancy equivalent to that of the halogen-based flame retardant (Comparative Example 4) was shown was evaluated as “◎”. The flame retardancy level was inferior to that of the halogen-based flame retardant, but there was no practical problem. The case was evaluated as “○”, and the case with practical problems was evaluated as “×”.

The gas generated in the flame retardancy test was collected, and the gas was analyzed by gas chromatography.
Here, the case where no halogen gas was confirmed is represented by “○”.
And the case where the halogen gas was confirmed was evaluated as “×”.
Was evaluated.

(Adhesion) A portion where the flame-retardant adhesive films are bonded to each other and a portion where the conductor and the flame-retardant adhesive film are bonded are cut out and left in a thermostat at 60 ° C. for one week. Each adhesive strength is TENSILON (made by Orientec)
Was measured by Here, the adhesive force between the adhesive films and between the conductor and the adhesive film, where the adhesive force exceeds 0.5 kg / cm, was evaluated as “○”.
Those with an adhesive force of 3 kg / cm or more and less than 0.5 kg / cm were evaluated as “Δ”, and those with less than 0.3 kg / cm were evaluated as “x”.

[0041]

(Table 1) (parts by weight) Example Flame-retardant adhesive component 1 2 3 4 5 6 7 Polyester resin 100 100 100 100 100 100 100 Nitrogen-containing organic flame retardant Melamine cyanurate 100 100 100 100--100 Melamine- − − − 100 − − Benzoguanamine − − − − − 100 − Boron compound (flame retardant aid) Zinc borate 10 50 100 150 50 50 − Manganese borate − − − − − − 50 (Evaluation) Flame retardancy ○ ◎ ○ ○ ◎ ◎ ○ Combustion gas ○ ○ ○ ○ ○ ○ ○ Electric resistance ○ ○ ○ ○ ○ ○ △ Adhesion ○ ○ ○ △ ○ ○ ○

[0042]

(Table 2) (parts by weight) Comparative example Flame retardant adhesive component 1 2 3 4 Polyester resin 100 100 100 100 Flame retardant melamine cyanurate 100 100--Ammonium polyphosphate--100-Tetrafluorophenyl phenyl oxide--- 60 Flame retardant auxiliary zinc borate--50-Aluminum hydroxide-50--Antimony trioxide---20 (Evaluation) Flame retardancy × × ◎ − Combustion gas ○ ○ ○ × Electric resistance ○ ○ × ○ Adhesion ○ ○ × ○

(Results) As is clear from Table 1, the flame-retardant adhesives of Examples 1 to 7 exhibited high values of electric resistance, flame retardancy and adhesive strength. In particular, the flame-retardant adhesive of Example 2, in which 50 parts by weight of zinc borate is added to 100 parts by weight of the polyester resin, has further improved flame retardancy while maintaining good electric resistance and adhesiveness. showed that.

Incidentally, the flame-retardant adhesive of Example 4 in which 150 parts by weight of zinc borate was added to 100 parts by weight of the polyester resin showed a tendency for the adhesive strength to decrease. From this, the amount of zinc borate added was changed to 100
It is understood that it is preferable not to exceed 150 parts by weight with respect to parts by weight.

The flame-retardant adhesives of Examples 5 and 6, which contain a nitrogen-containing organic flame retardant other than melamine cyanurate, have the same high electrical resistance as the flame-retardant adhesives of Examples 1 and 2, and have good electrical resistance. Excellent flame retardancy and adhesive strength.

On the other hand, as is clear from Table 2, the flame-retardant adhesive of Comparative Example 1, which is an example using no flame-retardant aid, has insufficient flame retardancy. Further, it can be seen that the flame-retardant adhesive of Comparative Example 2 using aluminum hydroxide as a flame-retardant aid also has a problem in flame retardancy. It can be seen that the flame-retardant adhesive of Comparative Example 3, which is an example using water-resistant ammonium polyphosphate as the flame retardant, has insufficient electric resistance. Moreover, the adhesiveness was not sufficient.

It can be seen that the flame-retardant adhesive of Comparative Example 4 using a conventional halogen-based flame retardant cannot solve the problem of combustion gas.

[0048]

According to the present invention, a non-halogen flame retardant is used, and a good flame insulating adhesive or a flame retardant adhesive film suitable for flat cable production is obtained. While maintaining flame retardancy comparable to halogenated flame retardants.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01B 7/295 H01B 7/34 B

Claims (9)

[Claims] 1. A composition comprising the following components (A), (B) and (C): (A) a polyester resin; (B) a nitrogen-containing organic flame retardant; and (C) a boron compound. Flame retardant adhesive. 2. Polyester resin 100 of component (A)
50 parts by weight of the component (B) nitrogen-containing organic flame retardant
To 150 parts by weight, based on 100 parts by weight of the total of the polyester resin of the component (A) and the nitrogen-containing organic flame retardant of the component (B), from 5 to 150 parts by weight of the boron compound of the component (C). Item 6. The flame-retardant adhesive according to Item 1. 3. Polyester resin 100 of component (A)
50 parts by weight of the component (B) nitrogen-containing organic flame retardant
To 100 parts by weight, and 10 to 100 parts by weight of the boron compound of the component (C) based on 100 parts by weight of the total of the polyester resin of the component (A) and the nitrogen-containing organic flame retardant of the component (B).
The flame-retardant adhesive according to claim 2, which contains parts by weight. 4. The flame-retardant adhesive according to claim 1, wherein the polyester resin as the component (A) is a phosphorus-added polyester resin having a phosphoric acid residue in the molecule. 5. The nitrogen-containing organic flame retardant of the component (B) is at least one selected from melamine, ammeline, ammelide, melam, melamine cyanurate, melamine resin and melamine derivative. The flame-retardant adhesive according to 1. 6. The flame retardant according to claim 1, wherein the boron compound as the component (C) is at least one selected from manganese borate, zinc borate, ammonium borate and lead borate. Adhesive. 7. The flame-retardant adhesive according to claim 6, wherein the boron compound as the component (C) is zinc borate. 8. The method according to claim 1, further comprising the step of:
A flame-retardant adhesive film, comprising a flame-retardant adhesive layer comprising the flame-retardant adhesive according to any one of the above. 9. A flat cable comprising an electric conductor covered with the adhesive film according to claim 8.