JP2005336381A - Flame retardant hot melt adhesive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flame retardant hot melt adhesive excellent in heat resistance, bending resistance, etc., having a high flame retardant property even without using an organic halogen compound or antimony trioxide as the flame retardant and having a strong bonding property with a polymer film such as a polyester, etc., even without being mediated by a primer layer. <P>SOLUTION: This flame retardant hot melt adhesive consists of (A) 40-80 wt. % thermoplastic polyester having 100-180°C softening point and -30 to 30°C glass transition temperature, (B) 1-5 wt. % synthetic wax having 100-180°C softening point, (C) 20-50 wt. % melamine cyanulate and (D) 3-10 wt. % red phosphorus. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a flame retardant hot melt adhesive for flat cables having excellent adhesiveness, 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, a flat cable has been proposed in which a plurality of foil-shaped conductors made of a conductive foil (for example, a bare copper foil) are sandwiched from both sides with an insulating base material or the like.

  Recently, this flat cable has been widely used for wiring of, for example, printers and automobiles, and demands for flame resistance, heat resistance, bending resistance, etc. are increasing. The main components are vinyl chloride (PVC), polyester, polyamide, polyolefin, etc., but further improvement is required.

  As a method of imparting flame retardancy to the hot melt adhesive, there are a method of adding a large amount of an inorganic material, a method of adding an organic halogen compound, etc., but when an organic halogen compound or antimony trioxide is used as a flame retardant, Since harmful gas is generated during combustion, it is not preferable. Further, when the amount of the flame retardant added is increased, there are disadvantages such as new problems such as lowering of adhesiveness and bending resistance and remarkably lowering of workability.

  In addition, many of the above flat cables have a structure in which an adhesive layer is provided via a primer layer on a polymer film such as polyester as an insulating substrate. Although the adhesion between the adhesive layer and the adhesive layer is improved, there are disadvantages such as a complicated process.

  The object of the present invention is excellent in heat resistance, flex resistance and the like, and has high flame retardancy without using an organic halogen compound or antimony trioxide as a flame retardant. An object of the present invention is to provide a flame retardant hot melt adhesive having strong adhesion to a molecular film.

  The present invention achieves such an object, and (A) 40 to 80% by weight of a thermoplastic polyester having a softening point of 100 to 180 ° C and a glass transition temperature of -30 to 30 ° C, and (B) softening. A flame retardant hot melt adhesive comprising 1 to 5% by weight of a synthetic wax having a point of 100 to 180 ° C, (C) 20 to 50% by weight of melamine cyanurate, and (D) 3 to 10% by weight of red phosphorus Is to provide.

  According to the present invention, it has excellent heat resistance, flex resistance, etc., and has high flame retardancy without using an organic halogen compound or antimony trioxide as a flame retardant. A flame retardant hot melt adhesive having strong adhesion to a molecular film can be obtained. For this reason, it is very useful for applications such as electrical wiring parts of electricity, electronic equipment, automobiles, and indoor / outdoor wiring for homes.

  The softening point of the polyester used in the present invention is 100 to 180 ° C, and particularly preferably 110 to 160 ° C. When the softening point is less than 100 ° C., the heat resistance is insufficient, and when it exceeds 180 ° C., the bonding temperature becomes high and the adherend may be damaged.

  The polyester used in the present invention has a glass transition temperature of -30 to 30 ° C, particularly preferably -15 to 10 ° C. When the glass transition temperature is 30 ° C. or less, strong adhesive strength is obtained by stress relaxation, but when the glass transition temperature is less than −30 ° C., blocking occurs.

  In the hot melt type flame retardant adhesive of the present invention, the polyester-based component (A) needs to be contained in an amount of 40 to 80% by weight, and particularly preferably 60 to 70% by weight. When the polyester-based component (A) is less than 40% by weight, flame retardancy is exhibited, but the adhesive strength is lowered. On the other hand, when the polyester-based component (A) exceeds 80% by weight, problems such as insufficient flame retardancy occur.

  The softening point of the wax used in the present invention is 100 to 180 ° C, and particularly preferably 110 to 130 ° C. When the softening point of the wax is lower than 100 ° C., the heat resistance is poor. On the other hand, when the wax exceeds 180 ° C., the bonding temperature becomes high and the adherend may be damaged.

  In the present invention, a synthetic wax is used because the softening point is relatively high. Examples thereof include polyethylene wax, polybutene wax, polypropylene wax, fatty acid ester wax, amine wax, amide wax, and the like. .

  When the wax is used in an amount of 1 to 5% by weight, and the wax is less than 1% by weight, the anti-blocking effect cannot be sufficiently exhibited. Decreases.

  The average particle diameter of the melamine cyanurate used in the present invention is preferably 1 to 5 μm. Those having an average particle size of 5 μm or less have good dispersibility, and a sufficient flame retardant effect can be obtained without causing the problem of poor appearance when the flat cable is bonded to the fish eye when it is formed into a film. Further, when the average particle size is 1 μm or more, the melt viscosity is not significantly increased.

  The red phosphorus used in the present invention functions as a flame retardant aid for melamine cyanurate, and the average particle size of red phosphorus is preferably 1 to 5 μm in order to increase the flame retardant effect. If the average particle diameter is 1 μm or more, the melt viscosity will not be significantly increased, and if it is 5 μm or less, a reduction in flame retardancy can be prevented.

  In the adhesive of the present invention, it is essential to use melamine cyanurate and red phosphorus in combination, but the proportion of melamine cyanurate needs to be in the range of 20 to 50% by weight. Particularly preferred is 25 to 35% by weight. When the melamine cyanurate is less than 20% by weight, flame retardancy cannot be exhibited, and when it exceeds 50% by weight, not only the adhesiveness is lowered but also the bending resistance is lowered.

  In the case of a phosphorus compound, the usage ratio of red phosphorus needs to be in the range of 3 to 10% by weight in terms of red phosphorus content. 5 to 6 weight% is especially preferable. If the amount of red phosphorus is less than 3% by weight, the effect as a flame retardant aid is insufficient, so that flame retardancy cannot be expressed, and if it exceeds 10% by weight, the melt viscosity increases. It is not preferable.

  Furthermore, in order to express the flame retardant effect, the mixing ratio of the flame retardant (C) component and the flame retardant auxiliary (D) component is preferably 2: 1 to 20: 1, particularly 4: 1 to 1. It is preferably 6: 1. Further, zinc borate, magnesium hydroxide, aluminum hydroxide, zinc sulfate, barium oxide, zirconium oxide and the like may be used in combination with red phosphorus.

  The adhesive of the present invention may contain stabilizers, additives, pigments, and the like as required so as not to impair the original properties of the adhesive.

  Various methods can be used for producing the adhesive of the present invention, and a melt mixing method is preferable. For example, a melting pot, a kneader, a mixing roll, an extruder, an internal mixer, and the like can be used.

Hereinafter, the present invention will be described more specifically with reference to examples.
The physical properties of the obtained adhesive were evaluated by the following methods.
1. Adhesiveness (peel strength)
(1) Between PET and conductor (copper foil) The obtained adhesive is sandwiched between a PET film with a thickness of 50 μm and a width of 10 mm and the copper surface (conductor) of a copper-clad board. Heat pressing was performed at a temperature of ° C. At this time, the thickness of the adhesive was adjusted to 50 μm. The 90-degree peel strength of the prepared test piece was measured at a tensile speed of 50 mm / min.
(2) Between PET-PET The obtained adhesive was sandwiched between PET films having a thickness of 50 μm and a width of 10 mm, and heated and pressed at a temperature of 150 ° C. using a hot press apparatus. At this time, the thickness of the adhesive was adjusted to 50 μm. The T-peel strength of the produced test piece was measured at a tensile speed of 50 mm / min.
2. Heat resistance The obtained adhesive was sandwiched between a PET film having a thickness of 50 μm and a width of 25 mm and the copper surface of a copper-clad plate, and heat-pressed at a temperature of 150 ° C. using a hot press apparatus. At this time, the adhesive area was adjusted to 25 mm × 25 mm (square) and the adhesive film thickness was adjusted to 50 μm. The specimen was left to stand for 24 hours in a constant temperature bath adjusted to 90 ± 2 ° C. under a load of 200 g and 300 g in the shear direction, and the presence or absence of dropping or the like was confirmed. At this time, those that did not fall were evaluated as ◯, and those that were dropped were evaluated as ×.
3. Flexibility
The specimen prepared by measuring the adhesive strength between PET and PET was left in a thermostatic bath at -20 ° C for 1 hour, and immediately wound around a round bar with a diameter of 8 mm to check whether cracks would occur. At this time, the case where cracks did not occur was evaluated as ○, and the case where cracks occurred was evaluated as ×.
4). Anti-blocking property It adjusted to the film form using the apparatus of the hot press so that the film thickness of the obtained adhesive agent might be set to 50 micrometers. Both the adhesive and the PET film were cut into a size of 50 mm × 50 mm and laminated alternately. A load of 1.25 kg was applied from the uppermost part of the laminate, and the laminate was allowed to stand at 50 ° C. for 24 hours to confirm whether there was blocking between the adhesive and the PET film. 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 A PET film having a thickness of 50 μm and a width of 25 mm and the obtained adhesive were heat-pressed using a hot press apparatus. At this time, the thickness of the adhesive was adjusted to 50 μm. The prepared test piece was placed vertically, and a flame was applied to the lower part for 10 seconds and then released to confirm self-extinguishing properties. At this time, what was self-extinguishing was evaluated as ○, and what was not self-extinguishing was evaluated as ×.

Example 1
67% by weight of polyester (Degussa DYNAPOL S 1450) having a softening point of 140 ° C. and a glass transition temperature of 0 ° C., 3% by weight of polyethylene wax having a softening point of 118-128 ° C. It knead | mixed at 180 degreeC for 1 hour using the axial mixer. Thereafter, 25% by weight of melamine cyanurate (MC-610, manufactured by Nissan Chemical Industries, Ltd.) and 5% by weight of red phosphorus (Novaexcel F-5, manufactured by Rin Chemical Industry Co., Ltd.), which is a flame retardant, are added. A hot-melt type flame retardant adhesive was prepared by kneading for a time.
A test piece was prepared using this adhesive, and the above-described various tests were performed. 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
A hot melt adhesive was prepared in the same manner as in Example 1 except that polyester (DYNAPOL S 1402 manufactured by Degussa) having a softening point of 100 ° C. and a glass transition temperature of −10 ° C. was used, 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 3
A hot melt adhesive was prepared in the same manner as in Example 1 except that polyester (DYNAPOL S 1401 manufactured by Degussa) having a softening point of 100 ° C. and a glass transition temperature of −25 ° C. was used, 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 4
A hot melt adhesive was prepared in the same manner as in Example 1 except that a polyester (DYNAPOL S 1227 manufactured by Degussa) having a softening point of 115 ° C. and a glass transition temperature of 10 ° C. was used, 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 5
A hot-melt adhesive was prepared in the same manner as in Example 1 except that polyester (DYNAPOL S 1427 manufactured by Degussa) having a softening point of 125 ° C. and a glass transition temperature of 30 ° C. was used, 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 6
A hot melt adhesive was prepared in the same manner as in Example 1 except that polybutene wax (VESTOWAX B912 manufactured by Degussa) having a softening point of 114 to 122 ° C. was used, test pieces were prepared, and various tests were performed. It was. 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 7-8
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.

Comparative Examples 1-8
A hot-melt type flame retardant adhesive was prepared in the same manner as in Example 1 except that the formulation in Example 1 was changed to the formulation in Table 2, and test pieces were prepared. Went. 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 9-11
A hot-melt adhesive was prepared in the same manner as in Example 1 except that the flame retardant and the flame retardant aid were changed as shown in Table 2, a test piece was prepared, and various tests similar to those in the example were performed. . As shown in Table 2, it was inferior in the flame retardance point.

Comparative Example 12
A hot melt adhesive was prepared in the same manner as in Example 1 except that polyester (DYNAPOL S 320 manufactured by Degussa) having a softening point of 120 ° C. and a glass transition temperature of −40 ° C. was used, and a test piece was prepared. Various tests similar to those of the examples were conducted. As shown in Table 2, the anti-blocking property was poor.

Comparative Example 13
A hot-melt adhesive was prepared in the same manner as in Example 1 except that polyester (DYNAPOL S 1420 manufactured by Degussa) having a softening point of 70 ° C. and a glass transition temperature of −10 ° C. was used, and a test piece was prepared. Various tests similar to those of the examples were conducted. As shown in Table 2, it was inferior in heat resistance.

Comparative Example 14
A hot-melt adhesive was prepared in the same manner as in Example 1 except that polyester (DYNAPOL S 1606 manufactured by Degussa) having a softening point of 150 ° C. and a glass transition temperature of 65 ° C. was used, and a test piece was prepared. Various tests similar to those of the examples were performed. As shown in Table 2, the adhesiveness was inferior.

Comparative Example 15
A hot-melt adhesive was prepared in the same manner as in Example 1 except that a compounded wax (organic / inorganic compounded product) having a softening point of 69 ° C. (POLYCOAT-1025 manufactured by Nippon Seiwa Co., Ltd.) was used. And various tests similar to those of the example were performed. As shown in Table 2, it was inferior in heat resistance.

ここで、ホウ酸亜鉛は水澤化学工業社製FRC-150、水酸化マグネシウムは協和化学工業社製KISUMA 5Jを使用した。

Here, FRC-150 manufactured by Mizusawa Chemical Industry Co., Ltd. was used as zinc borate, and KISUMA 5J manufactured by Kyowa Chemical Industry Co., Ltd. was used as magnesium hydroxide.

Claims (1)

  (A) 40 to 80% by weight of a thermoplastic polyester having a softening point of 100 to 180 ° C and a glass transition temperature of -30 to 30 ° C, and (B) a synthetic wax 1 to 5 having a softening point of 100 to 180 ° C. A flame-retardant hot-melt adhesive comprising: wt%, (C) melamine cyanurate 20 to 50 wt%, and (D) red phosphorus 3 to 10 wt%.