JP2008024786A - Flame-retardant hot-melt adhesive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flame-retardant hot-melt adhesive having both of excellent adhesiveness to an inorganic material such as a conductor, and an organic material such as a polymer film, and flame retardancy, and also having good antiblocking properties, and excellent heat resistance, insulation properties and flexibility. <P>SOLUTION: The flame-retardant hot-melt adhesive contains an alkene/(meth)acrylic acid copolymer containing at least an alkene monomer and a (meth)acrylic acid as monomer components, and a flame retardant. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a flame retardant hot melt adhesive, and more particularly to a flame retardant hot melt adhesive for flat cables having excellent adhesion, heat resistance, flex resistance and the like and high flame resistance.

  In recent years, it has become necessary to wire a large number of electric wires inside various home appliances, communication devices, OA devices, automobiles, and the like. However, as the electric wire used, a conductor having a substantially circular cross section such as a copper wire is coated with an insulating layer such as vinyl chloride, and many electric wires are bundled when used. And the operation | work which bundles this many electric wires had to be performed manually, and was very troublesome and inefficient. Moreover, in order to provide a large number of functions, an extremely large number of electric wires are required, and the conventional electric wires as described above have been unable to cope with them.

  From such a background, for example, a flat cable has been proposed in which a plurality of conductive wires made of a tin-plated annealed copper conductor (hereinafter abbreviated as a conductor) are covered with an insulating base material or the like from both sides using an adhesive.

  In recent years, this flat cable has been widely used for wiring of, for example, printers and automobiles, and demands for flame retardancy, heat resistance, bending resistance, and the like are increasing. By the way, as an adhesive for this flat cable, a material mainly composed of polyvinyl chloride (PVC), polyester, polyamide, polyolefin or the like is used.

  As a method of imparting flame retardancy to the adhesive, there is a method of adding a flame retardant such as an inorganic substance. However, when the amount of the flame retardant in the adhesive layer is increased in order to improve the flame retardancy, the adhesion with the conductor is lowered. On the other hand, if the amount of the flame retardant in the adhesive layer is decreased in order to improve the conductor adhesiveness, the flame retardance is lowered. That is, there is a drawback that conductor adhesion and flame retardancy are not compatible.

  In addition, many of the adhesives for flat cable use are solvent-type, which may require a solvent drying step in production, or may cause sick house syndrome or the like which has been a problem in recent years.

Therefore, a hot-melt type flame retardant adhesive composition containing maleic anhydride graft-modified polyethylene (Patent Document 1) and a hot-melt adhesive composition containing a melt-processable graft ethylene copolymer (Patent Document 2). Has been reported. However, even if those adhesive compositions are used, the adhesion to the conductor is not sufficient.
JP-A-10-130608 (refer to claim 1 etc.) Japanese translation of PCT publication No. 2003-514080 (see paragraphs 0010 to 0011)

  The present invention achieves both excellent adhesion to inorganic materials such as conductors and organic materials such as polymer films and excellent flame retardancy, as well as good anti-blocking properties, heat resistance, insulation and bending resistance. It aims at providing the flame-retardant hot-melt-adhesive excellent in property.

  The present invention relates to a flame retardant hot melt adhesive comprising an alkene / (meth) acrylic acid copolymer containing at least an alkene monomer and (meth) acrylic acid as monomer components and a flame retardant.

  The flame retardant hot melt adhesive of the present invention has both excellent adhesion to inorganic materials such as conductors and organic materials such as polymer films and excellent flame retardancy, and has good anti-blocking properties, Excellent heat resistance, insulation, and bending resistance. For this reason, it is very useful for applications such as electrical wiring parts of electric, electronic equipment, automobiles, and indoor / outdoor wiring for home use.

  The flame-retardant hot melt adhesive according to the present invention contains at least an alkene / (meth) acrylic acid copolymer and a flame retardant.

  The alkene / (meth) acrylic acid copolymer (hereinafter sometimes simply referred to as a copolymer) is a random type formed by linearly polymerizing at least an alkene monomer and (meth) acrylic acid as monomer components or It is a block type copolymer and is usually a random type copolymer.

  The alkene monomer is a branched or straight chain alkene monomer having 2 to 4 carbon atoms, and examples thereof include ethylene, propene, 1-butene, 2-butene, and 2-methylpropene. Although two or more types of alkene monomers may be used in combination, it is preferable to use ethylene alone from the viewpoint of relatively easy availability.

  (Meth) acrylic acid is used in a concept including both methacrylic acid and acrylic acid, and at least one of methacrylic acid or acrylic acid may be contained in the copolymer.

  The content of the (meth) acrylic acid monomer component in the copolymer is 5% by weight or more, particularly 5 to 15% by weight, based on the total monomers constituting the copolymer, from the viewpoints of adhesiveness and hygroscopicity. It is preferably 6 to 12% by weight. If it is less than 5% by weight, the adhesion between the adhesive layer and the conductor is insufficient. On the other hand, if it exceeds 15% by weight, the adhesion between the adhesive layer and the conductor is saturated. Further, the increase in (meth) acrylic acid content is not preferable because the hydrophilicity increases and the electric resistance when wet decreases.

  The content of the alkene monomer in the copolymer is not particularly limited as long as the (meth) acrylic acid content is within the above range, and is usually 85 to 95% by weight with respect to all monomers constituting the copolymer. In particular, 88 to 94% by weight is suitable.

  The copolymer may contain other monomers as constituent monomers in addition to the alkene monomer and (meth) acrylic acid.

  In the present invention, the softening point of the alkene / (meth) acrylic acid copolymer is preferably 50 ° C. or more from the viewpoint of more effectively improving the heat resistance, and 120 from the viewpoint of the low temperature heat sealability of the adhesive. It is preferable that it is below ℃. A more preferable softening point is 60 to 100 ° C.

In this specification, the softening point uses a value measured by the following method, but it does not have to be measured by the following method, and can be measured according to the same principle and principle as the method. As long as it is measured by any method.
(Measurement method) Vicat softening point; JIS K7206: 1999.

  The copolymer preferably has an MFR (melt flow rate) of 3 to 280 g / 10 minutes, more preferably 10 to 250 g / 10 minutes, from the viewpoint of film formability and adhesiveness by extrusion processing with a T die or the like. .

  In the present specification, MFR uses a value measured by a flow tester CFT-100D (manufactured by Shimadzu Corporation) under a condition of 190 ° C./2.16 kg load.

  The content of the alkene / (meth) acrylic acid copolymer in the adhesive of the present invention is not particularly limited as long as the object of the present invention is achieved, but more excellent balance between excellent adhesiveness and excellent flame retardancy is achieved. From the viewpoint of making it, 30 to 80% by weight, particularly 35 to 75% by weight is preferable with respect to the total amount of adhesive. Two or more types of alkene / (meth) acrylic acid copolymers may be used in combination, and in this case, the total content thereof may be within the above range. When two or more types of alkene / (meth) acrylic acid copolymers are used, the MFR and softening point of the mixture may be within the above ranges, respectively.

  The alkene / (meth) acrylic acid copolymer is available as a commercial product, and can be synthesized by a known method. For example, the copolymer is available as Nucleel N1214, N1525, N1560, N0903HC, N0908C, N410, N1108C, N1207C, etc., manufactured by Mitsui DuPont Polychemical Co., Ltd.

  As the flame retardant used in the present invention, a flame retardant conventionally known in the field of flame retardant hot melt adhesive can be used, and various organic flame retardants and inorganic flame retardants can be used.

Examples of the organic flame retardant include bromine-based flame retardant, nitrogen-based flame retardant, and phosphorus-based flame retardant.
As the brominated flame retardant, for example, a bromine atom-containing aromatic organic compound such as tetrabromobisphenol A (TBBA) or decabromodiphenyl oxide (DBDPO) is used. Commercially available brominated flame retardants include, for example, SAYTEX CP-2000 (manufactured by Nihon Albemarle), SAYTEX8010 (manufactured by Nihon Albemarle), Great Lakes BA-59P (manufactured by Great Lakes Chemical Japan), Frame Cut 120G (Tosoh Corporation) Manufactured) and the like.
As the nitrogen-based flame retardant, for example, a triazine ring-containing compound including melamine cyanurate, urea, melamine derivatives and the like is used. Melamine cyanurate is a condensate of melamine and cyanuric acid, and is available as, for example, a commercially available product MC-610 (manufactured by Nissan Chemical Co., Ltd.).
As the phosphorus-based flame retardant, for example, phosphate esters such as aromatic polyphosphates are used.

  Examples of the inorganic flame retardant include aluminum hydroxide, magnesium hydroxide, zinc borate, zinc sulfate, barium oxide, and zirconium oxide.

  Among the above flame retardants, organic flame retardants are preferable from the viewpoint of more effectively achieving both excellent adhesion and excellent flame retardant properties, more preferably brominated flame retardants, nitrogen-based flame retardants (particularly melamine cyanurate). ). Furthermore, melamine cyanurate is preferable from the viewpoint of environmental resistance.

  The flame retardant has an average particle size of 1 to 5 μm from the viewpoint of improving dispersibility in adhesives, preventing appearance defects due to fish eyes when formed into a film, preventing an increase in melt viscosity, and further improving flame retardancy. Is preferably used.

  The content of the flame retardant is preferably 10 to 50% by weight with respect to the total amount of the adhesive from the viewpoint of more effectively achieving both excellent adhesiveness and excellent flame retardancy and further improving flex resistance. Two or more kinds of flame retardants may be used in combination, and in that case, the total content thereof may be within the above range.

The adhesive of the present invention preferably further contains a flame retardant aid.
The flame retardant aid promotes the flame retardant effect of the flame retardant, and a flame retardant aid conventionally known in the field of flame retardant hot melt adhesives can be used. Examples include antimony trioxide, red phosphorus, antimony pentoxide, and the like.

  As the flame retardant aid, those having an average particle diameter of 1 to 5 μm are preferably used from the viewpoint of further improving flame retardancy and preventing increase in melt viscosity.

  The content of the flame retardant aid is preferably 3 to 20% by weight based on the total amount of the adhesive from the viewpoint of further improving the flame retardancy and preventing the increase in melt viscosity. Two or more flame retardant aids may be used in combination, and in that case, the total content thereof may be within the above range.

Among the above, the flame retardant aid is preferably selected as appropriate according to the flame retardant used, from the viewpoint of most effectively achieving both excellent adhesion and excellent flame retardancy.
Specifically, for example, when a brominated flame retardant is used as a flame retardant, it is preferable to use antimony trioxide as a flame retardant aid.
In addition, for example, when using a nitrogen-based flame retardant as the flame retardant, particularly melamine cyanurate, it is preferable to use red phosphorus as the flame retardant aid.

In the case where a brominated flame retardant and antimony trioxide are used in combination, the content of the brominated flame retardant is 10 to 35% by weight based on the total amount of the adhesive from the viewpoint of excellent adhesiveness and excellent flame resistance. In particular, the content is preferably 15 to 30% by weight, and the content of antimony trioxide is preferably 5 to 20% by weight, particularly 7 to 15% by weight, based on the total amount of the adhesive. In such a case, the content ratio (A ₁ : B ₁ ) of the brominated flame retardant (A ₁ ) and antimony trioxide (B ₁ ) is 1: 1 to 8: 1, particularly 2: 1 to 5 in weight ratio. : 1 is more preferable.

In the case of using a nitrogen-based flame retardant (particularly melamine cyanurate) and red phosphorus in combination, the content of the nitrogen-based flame retardant is relative to the total amount of the adhesive from the viewpoint of excellent adhesion and excellent flame resistance. It is preferably 20 to 50% by weight, particularly preferably 22 to 35% by weight, and the red phosphorus content is preferably 3 to 15% by weight, particularly 5 to 13% by weight, based on the total amount of the adhesive. In such a case, the content ratio (A ₂ : B ₂ ) of the nitrogen-based flame retardant (A ₂ ) and red phosphorus (B ₂ ) is 2: 1 to 20: 1, particularly 3: 1 to 6: 1 is more preferable.

  In order to improve the flame retardancy of the adhesive of the present invention, an inorganic filler such as calcium carbonate, calcium silicate, or talc can be contained. The content of the inorganic filler is not particularly limited as long as the object of the present invention is achieved, but it is, for example, 2 to 50% by weight, preferably 5 to 40% by weight, based on the total amount of the adhesive. be able to.

  The adhesive of the present invention may further contain a stabilizer such as an antioxidant and an ultraviolet absorber, and a pigment such as titanium oxide and carbon black within a range in which the object of the present invention is achieved.

  The adhesive of the present invention can be produced by various methods, but the melt mixing method is preferable. For example, the mixture composed of the various components described above may be melted and kneaded with a melting kettle, a kneader, a mixing roll, an extruder, an internal mixer, or the like. After kneading, usually a pellet-like adhesive can be obtained by cooling and cutting. Easily by pre-melting the obtained pellet-like adhesive, extruding it into organic or inorganic materials such as polymer films with a T-die, etc., heat-pressing and cooling the adherend It can be adhered to. The adhesion of the adherend can also be achieved by processing the adhesive in advance into a sheet shape, sandwiching the sheet adhesive with a predetermined adherend, heating and pressing, and cooling. The heating and pressing temperature is usually 120 to 190 ° C, particularly 130 to 180 ° C.

  The adhesive of the present invention is particularly useful for the production of so-called flat cables. A flat cable is formed by sandwiching and sandwiching a plurality of conductors made of conductors with two insulating base materials from both sides thereof. Used for bonding between insulating base and conductor. That is, the flat cable has an adhesive layer made of the flame-retardant hot melt adhesive of the present invention between two insulating base materials and between the insulating base material and the conductor.

  The insulating substrate is not particularly limited, and usually a polymer film is used. The polymer film is not particularly limited, and examples thereof include a polyethylene terephthalate film (hereinafter abbreviated as PET film), a polyimide film, and a polyethylene naphthalate film. Among these, a PET film is preferable because it has a good balance between mechanical strength, electrical insulation, heat resistance, and the like and cost.

Prior to the application of the adhesive, a primer layer is formed in advance on the insulating base, particularly on the polymer film surface, so that the adhesiveness between the adhesive and the base can be improved. The primer is not particularly limited, and a primer known in the field of flame retardant hot melt adhesive can be used. For example, an organic silane compound, an organic titanium compound, etc. are mentioned. Specific examples of the organic silane compound include, for example, 3-aminopropyltriethoxysilane, 3- (2-aminoethyl) aminopropyltrimethoxysilane (H ₂ N (CH ₂ ) ₂ NH (CH ₂ ) ₃ Si (OMe) ₃ ), 3- (2-aminoethyl) aminopropylmethyldimethoxysilane (H ₂ N (CH ₂ ) ₂ NH (CH ₂ ) ₃ Si (Me) (OMe) ₂ ) and other amino-based silane coupling agents In addition, epoxy silane coupling agents, vinyl silane coupling agents, isocyanate silane coupling agents, and the like can be used. Specific examples of the organic titanium compound include organic titanate compounds such as tetraisopropoxy titanium. A preferred primer is an amino silane coupling agent. This is because the non-shared electron pair of nitrogen of the amino group is coordinated to the carbonyl carbon of the alkene / (meth) acrylic acid copolymer contained in the adhesive layer, so that the adhesion is more effectively improved.

Hereinafter, the present invention will be described more specifically with reference to examples.
A-1 (manufactured by Nippon Soda Co., Ltd.) and SH6020 (manufactured by Dow Corning Toray) were used as primers.
As the calcium carbonate, Whiten SB (manufactured by Shiroishi Calcium Co., Ltd.) was used.
As brominated flame retardants, SAYTEX CP-2000 and SAYTEX8010 (manufactured by Nihon Albemarle) were used.
As antimony trioxide, PATOX-C (manufactured by Nippon Seiko Co., Ltd.) was used.
MC-610 (Nissan Chemical Co., Ltd.) was used as the melamine cyanurate.
As red phosphorus, Nova Excel F5 (manufactured by Rin Chemical Industry Co., Ltd.) was used.
JR-701 (manufactured by Teika) was used as the titanium oxide.

The physical properties of the obtained adhesive were evaluated by the following methods.
1. Adhesiveness (peel strength)
(1) Between PET and conductor A primer is applied and dried on a PET film having a thickness of 25 μm, and an adhesive layer (film thickness) is formed thereon using an extrusion laminator (Tanabe Plastics Co., Ltd., 40 mmφExt) at a temperature of 180 ° C. 40 μm) was laminated. Furthermore, a conductor (width 0.8 mm) having a thickness of 50 μm was heat-pressed using a laminator at 150 ° C. and a line speed of 1.8 m / min. The T-peel strength of the produced test piece was measured at a tensile speed of 50 mm / min (conductor width 0.8 mm). 0.8N or more is a practically acceptable range, preferably 1.0N or more, more preferably 1.2N or more, and most preferably 1.4N or more.
As a primer, A-1 was used in Examples 1 to 7, 9 and Comparative Examples 1 to 4, and SH6020 was used in Examples 8 and 10.

(2) Between PET-PET A primer is applied to a PET film having a thickness of 25 μm and dried, and then an adhesive layer (film thickness) at a temperature of 180 ° C. using an extrusion laminator (manufactured by Tanabe Plastics Co., Ltd., 40 mmφExt). 40 μm) was laminated. Further, the PET films were overlapped with each other with adhesives, and heated and pressed using a laminator at 150 ° C. and a line speed of 1.8 m / min. The T-peel strength of the produced test piece was measured at a tensile speed of 50 mm / min (test piece width 10 mm). 10N or more is a practically acceptable range, preferably 11N or more, more preferably 12N or more, and most preferably 14N or more.
The primer is the same as in the PET-conductor adhesive evaluation method.

2. Heat resistance The test piece (PET / adhesive layer / conductor) prepared by the PET-conductor adhesive evaluation method and the PET / adhesive layer laminate were superposed and heated at a temperature of 150 ° C. using a laminator. Then, a laminate of 25 μm thick PET / 40 μm thick hot melt adhesive layer / conductor / 40 μm thick hot melt adhesive layer / 25 μm thick PET was produced. The laminate was bent and allowed to stand at 113 ° C. for 7 days, and it was confirmed whether floating or the like occurred between the layers. At this time, a case where no floating occurred between any layers was evaluated as “◯”, and a case where floating occurred between any layers was evaluated as “×”.

3. Bending Resistance It was confirmed whether the laminate produced by the heat resistance evaluation method was bent or lifted in a normal state. At this time, a case where no floating occurred between any layers was evaluated as “◯”, and a case where floating occurred between any layers was evaluated as “×”.

4). Anti-blocking property The PET / adhesive layer laminate film produced by the PET-conductor adhesive evaluation method was cut into a size of 50 mm × 40 mm, and the PET layer and the adhesive layer were laminated alternately ( Total number of stacks 10). A load of 1.0 kg was applied from the uppermost part of this laminate, and it was allowed to stand at 70 ° C. for 48 hours, and the presence or absence of blocking between the adhesive and the PET film was confirmed. At this time, the case where blocking did not occur was evaluated as ◯, and the case where blocking occurred was evaluated as ×.
5. Flame retardancy: Measured according to UL standard VW-1, and evaluated self-extinguishing with ◯ and non-self-extinguishing with x.

6). Thermal Stability Gelation was observed when the adhesive was kneaded at 140 ° C. for 3 hours. The case where gelation did not occur was evaluated as ○, and the case where it occurred was evaluated as ×.

(Example 1)
Ethylene content 88% / methacrylic acid content 12%, MFR 14g / 10min, Vicat softening point 72 ° C ethylene / methacrylic acid copolymer (Mitsui / DuPont Polychemical Nucrel N1214) 38g, bromine A hot melt type flame retardant adhesive was prepared by kneading 18 g of a flame retardant, 7 g of antimony trioxide, and 37 g of calcium carbonate at 140 ° C. using a biaxial ruder. A primer was applied to a PET film having a thickness of 25 μm, and various tests were performed by laminating the adhesive and the like. As shown in Table 1, the obtained test results were excellent in all of adhesiveness, heat resistance, flex resistance, anti-blocking property, and flame retardancy.

(Example 2)
Ethylene content 85% / methacrylic acid content 15%, MFR 25 g / 10 min, Vicat softening point 63 ° C ethylene / methacrylic acid copolymer (Mitsui / DuPont Polychemical Nucrel N1525) 38 g, bromine A hot melt type flame retardant adhesive was prepared by kneading 18 g of a flame retardant, 7 g of antimony trioxide, and 37 g of calcium carbonate at 140 ° C. using a biaxial ruder. A primer was applied to a PET film having a thickness of 25 μm, and various tests were performed by laminating the adhesive and the like. As shown in Table 1, the obtained test results were excellent in all of adhesiveness, heat resistance, flex resistance, anti-blocking property, and flame retardancy.

(Example 3)
Ethylene content 85% / methacrylic acid content 15%, MFR 60 g / 10 min, Vicat softening point 60 ° C. ethylene / methacrylic acid copolymer (Mitsui / DuPont Polychemical Nucrel N1560) 38 g, bromine A hot melt type flame retardant adhesive was prepared by kneading 18 g of a flame retardant, 7 g of antimony trioxide, and 37 g of calcium carbonate at 140 ° C. using a biaxial ruder. A primer was applied to a PET film having a thickness of 25 μm, and various tests were performed by laminating the adhesive and the like. As shown in Table 1, the obtained test results were excellent in all of adhesiveness, heat resistance, flex resistance, anti-blocking property, and flame retardancy.

Example 4
Ethylene content 91% / methacrylic acid content 9%, MFR 3g / 10min, Vicat softening point 82 ° C ethylene / methacrylic acid copolymer (Mitsui / DuPont Polychemical Nucrel N0903HC) 38g, bromine A hot melt type flame retardant adhesive was prepared by kneading 18 g of a flame retardant, 7 g of antimony trioxide, and 37 g of calcium carbonate at 140 ° C. using a biaxial ruder. A primer was applied to a PET film having a thickness of 25 μm, and various tests were performed by laminating the adhesive and the like. As shown in Table 1, the obtained test results were excellent in all of adhesiveness, heat resistance, flex resistance, anti-blocking property, and flame retardancy.

(Example 5)
Ethylene content 88% / methacrylic acid content 12%, MFR 14g / 10min, Vicat softening point 72 ° C ethylene / methacrylic acid copolymer (Mitsui / DuPont Polychemical Nucrel N1214) 38g, melamine shear 24 g of nurate, 8 g of red phosphorus and 30 g of calcium carbonate were kneaded at 140 ° C. using a biaxial ruder to prepare a hot-melt type flame retardant adhesive. A primer was applied to a PET film having a thickness of 25 μm, and various tests were performed by laminating the adhesive and the like. As shown in Table 1, the obtained test results were excellent in all of adhesiveness, heat resistance, flex resistance, anti-blocking property, and flame retardancy.

(Examples 6 to 7)
A hot melt type flame retardant adhesive was prepared in the same manner as in Example 1 except that the formulation of Example 1 was changed to the formulation of Table 1, and test pieces were prepared and subjected to various tests. As shown in Table 1, the obtained test results were excellent in all of adhesiveness, heat resistance, flex resistance, anti-blocking property, and flame retardancy.

(Examples 8 to 10)
A hot-melt type flame retardant adhesive was prepared in the same manner as in Example 1 except that the blending of the copolymer and other components shown below was changed to the blending shown in Table 1, and a test piece was prepared. Various tests were conducted. As shown in Table 1, the obtained test results were excellent in all of adhesiveness, heat resistance, flex resistance, anti-blocking property, and flame retardancy.
Example 8: Mixture of 40% by weight of Nukurel N1525 (Mitsui / DuPont Polychemical) and 20% by weight of Nucrel N1560 (Mitsui / DuPont Polychemical) Example 9; Nucrel N1525 (Mitsui / DuPont Polychemical) ) Mixture of 40% by weight and 20% by weight of Nucrel N1560 (Mitsui / DuPont Polychemical Co.) Example 10: 60% by weight of Nucrel N0903HC (Mitsui / DuPont Polychemical Co.).

(Comparative Example 1)
Ethylene content 90% / methyl methacrylate content 10%, MFR 7g / 10min, Vicat softening point 75 ° C ethylene / methyl methacrylate copolymer (Sumitomo Chemical Co., Ltd. ACRlift WD301) 38g, brominated flame retardant 18g Then, 7 g of antimony trioxide and 37 g of calcium carbonate were kneaded at 140 ° C. using a biaxial ruder to prepare a hot-melt type flame retardant adhesive. A primer was applied to a PET film having a thickness of 25 μm, and various tests were performed by laminating the adhesive and the like. As shown in Table 2, the obtained test results were inferior in at least one of adhesiveness, heat resistance, flex resistance, anti-blocking property, and flame retardancy.

(Comparative Example 2)
Ethylene content 82% / Methyl methacrylate content 18%, MFR 7 g / 10 min, Vicat softening point 60 ° C. ethylene / methyl methacrylate copolymer (Sumitomo Chemical Co., Ltd. Aclift WH303) 38 g, Brominated flame retardant 18 g Then, 7 g of antimony trioxide and 37 g of calcium carbonate were kneaded at 140 ° C. using a biaxial ruder to prepare a hot-melt type flame retardant adhesive. A primer was applied to a PET film having a thickness of 25 μm, and various tests were performed by laminating the adhesive and the like. As shown in Table 2, the obtained test results were inferior in at least one of adhesiveness, heat resistance, flex resistance, anti-blocking property, and flame retardancy.

(Comparative Examples 3-4)
A hot melt type flame retardant adhesive was prepared in the same manner as in Example 1 except that the blending of the copolymer and other components shown below was changed to the blending shown in Table 2, and a test piece was prepared. Various tests were conducted.
Comparative Example 3 Bondin HX8140 (manufactured by Sumika Atchem; ethylene-acrylic acid ester-maleic anhydride terpolymer, MFR 20 g / 10 min, Vicat softening point 48 ° C.) 38% by weight
Comparative Example 4; Bond First 7B (Sumitomo Chemical Co., Ltd .; ethylene-glycidyl methacrylate-vinyl acetate terpolymer, MFR 7 g / 10 min, Vicat softening point 66 ° C.) 38% by weight.

  The flame retardant hot melt adhesive of the present invention is very useful as an adhesive used in electrical wiring parts of electronic devices and automobiles, or indoor and outdoor electrical wiring parts for home use or business use. It is particularly useful for the production of flat cables.

Claims (6)

  A flame-retardant hot-melt adhesive comprising an alkene / (meth) acrylic acid copolymer containing at least an alkene monomer and (meth) acrylic acid as monomer components and a flame retardant.   The flame retardant hot melt adhesive according to claim 1, wherein the alkene / (meth) acrylic acid copolymer contains 5 to 15% by weight of a (meth) acrylic acid monomer component.   The flame retardant hot melt adhesive according to claim 1 or 2, wherein the content of the alkene / (meth) acrylic acid copolymer is 30 to 80% by weight based on the total amount of the adhesive.   The flame retardant hot melt adhesive according to any one of claims 1 to 3, wherein the flame retardant is a brominated flame retardant and further contains antimony trioxide.   The flame retardant hot melt adhesive according to any one of claims 1 to 3, wherein the flame retardant is melamine cyanurate and further contains red phosphorus.   The flame retardant hot melt according to any one of claims 1 to 5, wherein the conductor is coated and sandwiched between two insulating base materials, and between the two insulating base materials and between the insulating base material and the conductor. A flat cable having an adhesive layer made of an adhesive.