JPH07150126A - Flame-retardant adhesive - Google Patents

Abstract

PURPOSE:To improve flame retardancy and heat resistance by compounding a thermoplastic high-molecular weight polyester with a brominated phosphoric ester and an inorg. filler. CONSTITUTION:100 pts.wt. thermoplastic high-molecular weight polyester is compounded with 20-150 pts.wt. brominated phosphoric ester and 1-50 pts.wt. inorg. filler. The polyester is produced by the polycondensation of a dicarboxylic acid (e.g. terephthalic acid) with a diol (e.g. ethylene glycol) and has a mol.wt. of 10,000-30,000. An example of the phosphoric ester is tris(dibromophenyl) phosphate. An example of the filler is calcium carbonate, pref. having an average particle size of about 1mum or lower. Regardless of the shape of the adhesive, its flame retardance and heat resistance are improved by the exposure to a radiation such as an electron beam or gamma-ray. The dose of the radiation is usually 50-300kGy, though varied by various factors.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to improvements in flame retardant adhesives.

[0002]

2. Description of the Related Art In recent years, electronic devices have been required to be compact, lightweight and space-saving. In response to such requests,
Electronic devices include flexible printed wiring boards, flat cables, etc. that are lightweight, compact, and can be bent. Then, for example, in a flexible printed wiring board, an adhesive is often used such that a printed circuit is adhered to the insulating film by the adhesive.

Heat resistance and flame retardancy are often essential for adhesives used in such applications. For example, a saturated copolyester resin is used as a main component, and a brominated organic flame retardant and an inorganic flame retardant are used. It has been proposed to add a filler and dissolve these components in an organic solvent (JP-A-62-9).
6580).

As the brominated organic flame retardant in this adhesive, decabromodiphenyl oxide, hexabromobenzene, tris (2,3-dibromopropyl) isocyanurate, 2,2-bis (4-hydroxy-3,
5-dibromophenyl) propane or 2,2-bis (4-hydroxyethoxy-3,5-dibromophenyl) propane is used.

[0005]

By the way, there is a severe demand for improving the performance of electronic devices, and therefore, the adhesives used in the devices are also required to have improved heat resistance and flame retardancy.

[0006]

Means for Solving the Problems As a result of intensive research to meet the above requirements, the present inventor has found that heat resistance and flame retardancy can be improved by using a completely different bromine-containing phosphate ester as a flame retardant. Heading out, the present invention has been completed.

That is, the flame-retardant adhesive according to the present invention contains 20 to 150 parts by weight of bromine-containing phosphate and 100 parts by weight of a thermoplastic high molecular weight polyester and 1 part of the inorganic filler.
-50 parts by weight are compounded.

The thermoplastic high molecular weight polyester used in the present invention is a linear saturated polyester obtained by polycondensation of a dicarboxylic acid and a diol, and has a molecular weight of about 1
10,000 to 30,000. As the above-mentioned dicarboxylic acid, an aromatic dicarboxylic acid such as terephthalic acid and isophthalic acid, and an aliphatic dicarboxylic acid such as adipic acid and sebacic acid, and as the diol, ethylene glycol, 1,4-butanediol, diethylene glycol, Neopentyl glycol or the like can be used.

Such thermoplastic high molecular weight polyesters are already commercially available, for example, under the trade names of Byron 30P, Byron 900, Byron 990 from Sumitomo Chemical Co., Ltd., and VC-40, VC-60 by Sumitomo Chemical Co., Ltd. Therefore, these can be obtained and used.

In the present invention, the bromine-containing phosphoric acid ester is mixed in a proportion of 20 to 150 parts by weight with respect to 100 parts by weight of the thermoplastic high molecular weight polyester. These give flame retardancy to the adhesive, and the compounding amount is 20
If it is less than 1 part by weight, excellent flame retardancy cannot be imparted, and if it is blended in a large amount in excess of 150 parts by weight, the adhesive strength is lowered, which is not preferable. Specific preferred examples of the bromine-containing phosphate ester include tris (dibromophenyl) phosphate, tris (tribromoneopentyl) phosphate, tris (tribromophenyl) phosphate, and the like.
This bromine-containing phosphate ester is commercially available from Daihachi Chemical Industry Co., Ltd. under the trade names of PR900, PPX-50, PPX-33 and the like.

In the present invention, 1 to 50 parts by weight of an inorganic filler is added as a flame retardant aid to 100 parts by weight of the thermoplastic high molecular weight polyester. By blending such a specific amount of the inorganic filler, it is possible to reduce the amount of expensive bromine-containing phosphate used while maintaining a high flame retardancy level. If the compounding amount of the inorganic filler exceeds 50 parts by weight, the adhesiveness tends to decrease.

As the inorganic filler, calcium carbonate, aluminum silicate, calcium fluoride, silicon dioxide, aluminum oxide, aluminum hydroxide, antimony trioxide, magnesium oxide, titanium oxide, silica or the like can be used. Although not limited, these inorganic fillers are preferably used as powders having an average particle size of about 1 μm or less from the viewpoint of dispersibility with thermoplastic high molecular weight polyesters and bromine-containing phosphates. .

The present invention comprises a thermoplastic high molecular weight polyester, a bromine-containing phosphoric acid ester and an inorganic filler as essential components as described above, but if desired, a stabilizer (copper, iron, etc.), an antioxidant, An appropriate amount of additives such as an anti-aging agent and a coloring agent can be blended.

The flame-retardant adhesive according to the present invention can be used as a powder or pellets in which a thermoplastic high molecular weight polyester, a bromine-containing phosphate ester and an inorganic filler are mixed, and also as a film containing these components. You can also do it. In the present invention, it has been found that regardless of the shape of the adhesive, irradiation with radiation such as electron beams and gamma rays further improves flame retardancy and heat resistance. The radiation dose may vary depending on various factors, but is usually about 50 to 300 KGy.

[0015]

EXAMPLES The present invention will be described in more detail below with reference to examples.

Example 1 Using terephthalic acid and sebacic acid as dicarboxylic acids and ethylene glycol and neopentyl glycol as diols, a thermoplastic high molecular weight polyester obtained by polycondensation of these (manufactured by Toyobo Co., Ltd., trade name Byron GM990) ) Is prepared.

Then, with respect to 100 parts by weight of this thermoplastic high molecular weight polyester, tris (dibromophenyl) phosphate (manufactured by Daihachi Chemical Industry Co., Ltd., trade name CR-90) is used.
0) 20 parts by weight, 5 parts by weight of antimony trioxide having an average particle size of 0.3 μm, and 2 parts by weight of an antiaging agent (trade name: Irganox 1010 manufactured by Ciba Geigy Co., Ltd.) are uniformly mixed. Next, this mixture was extruded into a film (thickness: 60 μm) at a temperature of 180 ° C., and then irradiated with an electron beam at 50 KGy in the air to obtain a flame-retardant adhesive (Sample 1).

Example 2 The blending amounts (parts by weight) of thermoplastic high molecular weight polyester, tris (dibromophenyl) phosphate, antimony trioxide, antiaging agent (Irganox 1010) and electron beam irradiation dose (KGy) are shown in Table 1. The same operation as in Example 1 except that the above settings were made, and two types (Samples 2 and 3) were used.
A film-shaped flame-retardant adhesive of was obtained.

In Table 1, the thermoplastic high molecular weight polyester, which is a blending component, is designated as "A", tris (dibromophenyl) phosphate is designated as "B", antimony trioxide is designated as "C", and the antioxidant is designated as "D". displayed.

Example 3 A film-like flame-retardant adhesive (Sample 4) was obtained in the same manner as in Example 1 except that the electron beam irradiation was not performed.

Test Example The film-shaped flame-retardant adhesive obtained in Examples 1 to 3 above is laminated on one side of a polyethylene terephthalate film having a thickness of 50 μm at a temperature of 80 ° C. to obtain a film with an adhesive layer.

Next, the film with the adhesive layer is superposed on one surface of a copper foil (thickness: 100 μm), and is bonded through a pair of pressure-bonding rolls. The surface temperature of the pressure bonding roll was adjusted to a surface temperature of 160 ° C. and a linear pressure of 20 kg / cm ² .

The normal adhesive strength of this adhesive and 1
The adhesive strength after heat deterioration at 35 ° C. for 7 days is IPCFC2.
The results measured according to the 40-A standard are shown in Table 1. The unit of the adhesive force is "kg / 1 cm width". In addition, Table 1 also shows the results of measuring the oxygen index of this adhesive body (by the method of JIS K 7201).

[0024]

[Table 1]

Comparative Example 1 Blending amount (parts by weight) of thermoplastic high molecular weight polyester, bromine-containing phosphate ester, antimony trioxide, and antioxidant
Further, the same operation as in Example 1 was carried out except that the irradiation dose (KGy) of the electron beam was set as shown in Table 2 to obtain four kinds of film adhesives (Samples 5 to 8). Table 2 also shows the results obtained by testing these film adhesives in the same manner as described above.

[0026]

[Table 2]

Example 4 To 100 parts by weight of a thermoplastic high molecular weight polyester, 150 parts by weight of tris (dibromophenyl) phosphate, 45 parts by weight of antimony trioxide and 2 parts by weight of an antioxidant were blended, and electron beam irradiation was carried out. A film-like flame-retardant adhesive was obtained in the same manner as in Example 1 except that the amount was 300 KGy. When this adhesive was tested in the same manner as above, the normal adhesive strength was 3.61 kg / 1 cm width, the adhesive strength after deterioration was 2.74 kg / 1 cm width, and the oxygen index was 36.4.

Comparative Example 2 Thermoplastic high molecular weight polyester (manufactured by Toyobo Co., Ltd.,
Brand name Byron 300) 100 parts by weight of decabromodiphenyl ether 50 parts by weight, antimony trioxide 2
5 parts by weight and anti-aging agent (Irganox 1010)
A flame-retardant adhesive was obtained by dissolving 2 parts by weight in 200 parts by weight of toluene.

This flame-retardant adhesive was applied to one side of a polyethylene terephthalate film having a thickness of 50 μm,
It heated at 5 degreeC for 5 minutes, and obtained the film with an adhesive layer. When tested in the same manner as above, the normal adhesive strength was 2.34.
kg / 1cm width, adhesive strength after deterioration is 1.37kg / 1cm
The width and oxygen index were 33.3.

[0030]

EFFECTS OF THE INVENTION Since the present invention contains the bromine-containing phosphoric acid ester and the inorganic filler in the thermoplastic high molecular weight polyester as described above, it has excellent flame retardancy and heat resistance and is useful for bonding various articles. Is.

Claims (2)

[Claims] 1. A flame-retardant adhesive obtained by mixing 20 to 150 parts by weight of a bromine-containing phosphoric acid ester and 1 to 50 parts by weight of an inorganic filler with 100 parts by weight of a thermoplastic high molecular weight polyester. 2. The flame-retardant adhesive according to claim 1, which is in the form of a film and is irradiated with radiation.