JPH0134255B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for thermally bonding metal foil and polyamide film or sheet. More specifically, when thermally bonding a metal foil and a polyamide film or sheet, the metal foil is pretreated with an organic or inorganic alkali, and an amino group-containing alkyltrialkoxysilane is applied to the metal foil and dried, or A metal foil characterized in that an organic or inorganic alkali is added to an amino group-containing alkyltrialkoxysilane without pretreatment, and this is applied to the metal foil, dried, and then a polyamide film or sheet is thermally bonded. The present invention relates to a method for adhering polyamide films or sheets.

Conventionally, there have been many proposals for laminating metal foil and polyamide film or sheet by thermal adhesion for use in electric heating blankets, electronic carpets, and the like. However, since the polyamide film or sheet in the laminate produced by this method has strong water absorption, it is necessary to perform masking to prevent water absorption at the same time as thermal adhesion, and when it is left in the air, it will naturally peel off, making it impractical. It becomes a thing. Therefore, in order to improve adhesion, various silane coupling agents are applied to metal foil, dried, and then bonded to a polyamide film or sheet by heat bonding. Alternatively, various silane coupling agents are used to improve adhesive strength and mass productivity. A method has also been proposed in which a coupling agent is applied to metal foil and dried, then a polyamide film or sheet is extruded, laminated and bonded, and then heated and cured in an oven or tunnel furnace. However, in a method that simultaneously improves the adhesive strength and mass productivity described above, after applying various silane coupling agents to metal foil and drying them,
When polyamide films or sheets are extruded and laminated and then cured by heating in an oven or tunnel furnace, numerous voids often occur at the interface between the polyamide film or sheet and the metal foil, resulting in a decrease in adhesive strength and a decrease in the withstand voltage of this laminate. This may result in a product with low practical value.

As a result of various studies in order to permanently and permanently improve adhesive strength, the inventors of the present invention found that among various silane coupling agents, trialkoxysilane, which has a particularly strong chemical bond with the metal foil surface, was used. We succeeded in selecting a reactive alkyltrialkoxysilane containing an amino group.
However, a good product may also be obtained by applying this silane coupling agent to a metal foil by the method described above and drying it, then extrusion laminating it to a polyamide film or sheet, and then heat-treating it.
In most cases, numerous voids occur at the interface between the polyamide film or sheet and the metal foil, which often results in a decrease in adhesive strength and withstand voltage, and it has been found that there are many obstacles to commercialization.

Therefore, the present inventors investigated various methods of thermally bonding this metal foil and a polyamide film or sheet, and found that when thermally bonding a metal foil and a polyamide film or sheet, the metal foil is pre-treated with an organic or inorganic alkali. After applying the amino group-containing alkyltrialkoxysilane to the metal foil and drying it, or without pre-treating the metal foil, add an organic or inorganic alkali to the amino group-containing alkyltrialkoxysilane and apply it to the metal foil. A method has been developed in which a polyamide film or sheet is thermally bonded after coating the foil and drying it.

The metal foil used in the present invention may be any metal foil that is thin, ductile, and has good electrical conductivity, such as aluminum, copper, tin, gold, silver, chrome, or tungsten.

Polyamides are also used as heat-sensitive elements, such as poly ε-caprolactam (nylon 6), polyhexamethylene diammonium adipate (nylon 66), polyhexamethylene diammonium sebacate (nylon 610), and polyundecane amide. There are polyamides such as (nylon 11) and polydodecanamide (nylon 12).

In addition, these polyamides may contain amphoteric or nonionic surfactants, polyol-based or polyester-based plasticizers, copper halides or copper halide complex salts, or certain specific alkali metals, alkali metals, and metal halides. It is also possible to add and blend combinations. (Special Publication No. 10978, Showa 48-10978,
Among these polyamides, polyundecaneamide (nylon 11) or polydodecanamide (nylon 12), which has particularly low hygroscopicity, is preferably used. Also,
Examples of organic or inorganic alkalis used in the present invention include tertiary amines, phosphine, aluminium, quaternary amines,
Examples include class ammonium-phosphonium-aluminum salts, tertiary sulfonium salts, elemental metals of Group A and Group A, or their oxides, hydroxides, amidates, alcoholates, phenolates, organic acid salts, borates, and the like.

Further, in the present invention, it is important to use an amino group-containing alkyltrialkoxysilane as an essential requirement. Various silane coupling agents are commercially available, but the most advantageous are trialkoxysilanes that have a strong chemical bond with the metal foil surface, and amino group-containing alkyltrialkoxysilanes that have chemical reactivity with polyamides. This is because I discovered that it can be used.

Methods for thermally bonding metal foil and polyamide film or sheet include an extrusion lamination bonding method and a hot press method.

The effects of the present invention will be explained below using Examples, but the present invention is not limited to these Examples.

Example 1 An aluminum thin film (thickness: 20μ) was immersed in a 5% NaOH aqueous solution for 5 minutes, then washed with water and dried (150°C).
for 5 minutes).

0.5% to this pre-treated aluminum thin film
H ₂ NC ₂ H ₄ NHC ₃ H ₆ Si (OCH ₃ ) ₃ Methanol solution (amino group-containing alkyltrialkoxysilane,
KBM603 (manufactured by Shin-Etsu Silicone Co., Ltd.) was applied with a doctor blade, dried at 150℃ for 5 minutes, and then laminated on both sides to a nylon 12 sheet (thickness 200μ).
Kg/cm ² and pressed for 1 minute at 200°C.

The adhesive strength between the aluminum thin film and the nylon 12 sheet was measured using a 180° peel test (peel speed 200 mm/min) on this laminate sheet.
It was 1.09Kg/cm. After this laminate was left at room temperature for one week, the adhesive strength was measured to be 1.03.
It maintains an adhesive strength of Kg/cm. Furthermore, the withstand voltage is
It was 1200V.

Example 2 In Example 1, 0.2 parts of NaOH was added to 100 parts of 0.5% KBM603 methanol solution, this solution was applied to an untreated aluminum thin film with a doctor blade, and after drying at 150°C for 3 minutes, Example 1
The adhesive strength was measured using the same method as above and found to be 0.95 kg/cm.

Comparative Example 1 A 0.5% KBM603 methanol solution was applied directly to an aluminum thin film, dried at 150℃ for 3 minutes, and then laminated on both sides of a nylon 12 sheet at 5Kg/cm ² at 200℃.
Press for 1 minute.

The adhesive strength of this laminate was 0.35 kg/cm.

Incidentally, when this laminate product was left as it was at room temperature, spontaneous peeling occurred within the first week.

Claims (1)

[Claims] 1. When thermally bonding a metal foil and a polyamide film or sheet, the metal foil is pretreated with an organic or inorganic alkali, and an amino group-containing alkyltrialkoxysilane is applied to the metal foil and dried, or the metal foil is A metal foil and polyamide characterized in that an organic or inorganic alkali is added to an amino group-containing alkyltrialkoxysilane without pretreatment, this is applied to the metal foil and dried, and then a polyamide film or sheet is thermally bonded. A method of adhering films or sheets.