JPH0692556B2 - Vinylidene fluoride composite material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a vinylidene fluoride-based composite material in which a vinylidene fluoride resin and a metal substrate are firmly bonded together.

(Prior art) Since vinylidene fluoride resin has excellent chemical resistance, heat resistance, and weather resistance, it can be easily molded at relatively low temperatures.
It is widely used as a laminated composite material with other polymer materials. However, vinylidene fluoride resin has particularly poor adhesiveness to metal materials, which makes it difficult to form a practical composite material.

In order to improve the adhesion of a vinylidene fluoride resin to a metal material, JP-A-52-51479 discloses that aluminum or an aluminum alloy is etched, and a fluorine resin dispersion is applied to the aluminum or aluminum alloy. A method of hot pressing a resin film is disclosed. However, this method has complicated steps.

JP-A-55-61961 discloses that a primer consisting of an aqueous dispersion of a vinylidene fluoride resin containing chromium ions and hydrogen ions is applied to a metal surface, and then a vinylidene fluoride resin powder is deposited thereon. A method of heating and sintering this is disclosed. However, this method is also complicated in process, and pinholes peculiar to powder coating are generated in the obtained composite material.

In order to solve such a drawback, Japanese Patent Laid-Open No. 56-133309 discloses a composite material in which a vinylidene fluoride resin is graft-bonded with an acrylic acid or methacrylic acid polymer and which is adhered to a metal. ing. This material has strong adhesion between vinylidene fluoride resin and metal,
In the formation of the resin material, a vinylidene fluoride resin grafting step is required, and in the grafting step, a chain inhibitor such as copper sulfate or ferrous sulfate is added in order to prevent the formation of an acrylic homopolymer. Must be grafted in the presence of water containing Such an operation is complicated.

(Problems to be Solved by the Invention) The present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a vinylidene fluoride-based composite having good adhesion between a vinylidene fluoride resin and a metal substrate. To provide the material. Another object of the present invention is to provide a vinylidene fluoride-based composite material which can be easily obtained by a general melt molding method such as extrusion molding.

(Means for Solving Problems) In the present invention, an organosilicon compound is graft-polymerized on a vinylidene fluoride resin previously irradiated with ionizing radiation, and the grafted vinylidene fluoride resin is coated on a metal substrate. According to the inventor's findings, a vinylidene fluoride-based composite material in which a resin and a metal are firmly bonded can be obtained by a simple process.

The vinylidene fluoride-based composite material of the present invention is obtained by coating a composition containing a vinylidene fluoride resin pre-irradiated with ionizing radiation and an organosilicon compound represented by the following formula on a metal substrate. The purpose is achieved.

Here, R is an olefinic hydrocarbon group, Y is a hydrolyzable organic group, and R'is R or Y.

In another vinylidene fluoride-based composite material of the present invention, a composition obtained by further adding an organic filler and / or an inorganic filler to the above composition is coated on a metal substrate, whereby the above object is achieved. It

Vinylidene fluoride resin refers to vinylidene fluoride homopolymers and copolymers of vinylidene fluoride and other monomers. Examples of the monomer include ethylene, propylene, vinyl chloride, halogenated ethylene such as tetrafluoroethylene, dichlorofluoroethylene, and 1,1.2-trifluoro-2-chloroethylene. Such monomers are
It is contained in the copolymer at a ratio of 5 mol% or less.
When it exceeds 5 mol%, the properties of the vinylidene fluoride resin are impaired. Commercially available products include KF Polymer (produced by Kureha Chemical Co., Ltd.) and Kainer (produced by Penwalt).

The ionizing radiation includes, for example, β rays, γ rays, α rays, neutron rays, X rays, and accelerated electron beams, and γ rays and accelerated electron beams are particularly preferable. Gamma rays are preferred for the granular vinylidene fluoride resin. The sheet-shaped vinylidene fluoride resin is continuously irradiated with an electron beam and then pelletized. The dose of radiation is considered to be 0.1 megarad or more. Below 0.1 megarad, the desired adhesion to the metal cannot be obtained even if the organosilicon compound is added and mixed in the subsequent process. Although the maximum dose is not particularly limited, a large amount of irradiation causes the vinylidene fluoride resin to decompose, which is undesirable because the resin is colored and deteriorated.

Organosilicon compounds include alkoxy groups, acyloxy groups,
It contains a hydrolyzable organic group such as an oxime group and a substituted amino group, and an olefinic hydrocarbon group. Such organosilicon compounds include vinyltrimethoxysilane,
Examples include vinyltriethoxysilane. The organosilicon compound is used in an amount of 0.1 to 10 per 100 parts by weight of vinylidene fluoride resin.
It is contained in an amount of 0.3 to 5 parts by weight, preferably 0.3 to 5 parts by weight. If the amount is less than 0.1 part by weight, the desired adhesion with metal cannot be obtained. If the amount exceeds 10 parts by weight, the adhesiveness does not improve so much and the properties of the vinylidene fluoride resin are impaired.

As the metal substrate, any known metal can be used, and examples thereof include aluminum and its alloys, iron and its alloys, stainless steel, copper and its alloys. The surface of the metal substrate is preferably washed with acid, alkali, detergent, organic solvent or the like. Surface treatment such as chemical conversion treatment or oxidation treatment may be performed. Also, blasting, sandpaper treatment, plating or thermal spraying may be applied. However, conventional etching and treatment with vinylidene fluoride primer are not required.

The shape of the metal substrate is arbitrary, and in particular, if it is tubular, a composite tube excellent in chemical resistance, heat resistance, weather resistance, and adhesiveness can be obtained.

The vinylidene fluoride-based composite material of the present invention is obtained by melt-kneading a vinylidene fluoride resin and an organosilicon compound which have been previously irradiated with ionizing radiation, and directly coating the kneaded product on a metal substrate. A kneading machine such as a single-screw or twin-screw extruder and a Banbury mixer is used for the melt kneading. The kneading temperature is preferably 150 to 250 ° C. 150 ° C
Below this, the vinylidene fluoride resin does not melt, and the kneading of the vinylidene fluoride resin and the organosilicon compound becomes insufficient. Above 250 ° C, the vinylidene fluoride resin is markedly colored during melt-kneading, and the decomposition reaction is accelerated, so that toxic substances such as hydrofluoric acid are generated. Although the kneading time is not particularly limited, if the kneading is performed for a too long time, the vinylidene fluoride resin is decomposed. The melt-kneaded product may be once cooled and solidified into granules, and then melt-kneaded as it is or by adding an additive such as an antioxidant or an infrared absorber, and the melt-kneaded product may be coated on a metal substrate.

When the composite material of the present invention is formed into a composite tube by using a tubular metal substrate, a powder coating method in which a melt-kneaded product containing a vinylidene fluoride resin and an organosilicon compound pre-irradiated with ionizing radiation is sprayed on the metal tube or There is a lining method in which a kneaded product is formed into a film or sheet and is lined on a metal tube. By either method, a composite tube in which the vinylidene fluoride resin and the metal substrate are firmly bonded can be obtained. In the production of composite pipes, strip-shaped metal is continuously formed into a tubular shape, and while the ends are welded to obtain a metal pipe, the resin is extruded from the mold onto the inner surface of the metal pipe, and The resin is coated. The outer surface of the metal tube may be coated with a resin as needed.

An organic or inorganic filler may be further added to the composite material of the present invention in order to improve the adhesion with a metal. The vinylidene fluoride resin has a large linear expansion coefficient, and therefore the adhesiveness is reduced due to the difference in the linear expansion coefficient with the metal. The coefficient of linear expansion of vinylidene fluoride resin (0.7-1.
5) × 10 ^-4 / ℃, aluminum is 0.23 × 10 ^-4 /
℃, and iron is 0.11 × 10 ^-4 / ℃. In particular, after coating a melt-kneaded product of vinylidene fluoride resin on a metal substrate,
When cooled, the resin is likely to peel off. Therefore, as the organic or inorganic filler, a substance that lowers the linear expansion coefficient of vinylidene fluoride resin is preferable. Examples of the organic filler include powder of thermosetting resin such as phenol resin and melamine resin, organic fiber such as carbon fiber and aramid fiber, graphite, and wood powder. Examples of the inorganic filler include talc, mica, inorganic fine powder such as calcium carbonate, glass fiber, and inorganic fiber such as potassium titanate fiber. The organic or inorganic filler is added in an amount of 300 parts by weight or less, preferably 5 to 100 parts by weight, based on 100 parts by weight of the vinylidene fluoride resin. When it exceeds 300 parts by weight, the properties of vinylidene fluoride resin are impaired. The filler may be added either during mixing or during melt kneading.

(Examples) The present invention will be described below with reference to Examples.

Example 1 Vinylidene fluoride resin powder (KF polymer ^# 1100, manufactured by Kureha Chemical Co., Ltd.) was placed in a polyethylene container and irradiated with 1.0 g of de-γ rays ( ⁶⁰ Co) in the air. To 100 parts by weight of this γ-ray-irradiated vinylidene fluoride resin, 2.0 parts by weight of vinyltrimethoxysilane (VTS-M, manufactured by Chisso Corporation) was added and mixed for 5 minutes with a Henschel mixer. The mixture was extruded at a temperature of a cylinder part of 220 ° C. and a mold of 200 ° C. using a twin-screw extruder having a diameter of 30 mm to obtain a pelletized vinylidene fluoride resin composition. Aluminum plate (Aluminum ^# 30
04-O material, made by Sumitomo Light Metal Co., Ltd., thickness 0.25mm) 10% of 50 ℃
After treating with a sodium hydroxide solution, the resin composition was placed on the surface. This was preheated at 220 ℃ for 3 minutes and then pressed at a pressure of 10 kg / cm ² for 1 minute.
A 20 cm square vinylidene fluoride-aluminum laminate having a 1 mm thick vinylidene fluoride resin layer was obtained. A 180-degree peeling test (peeling an aluminum plate against a vinylidene fluoride resin layer at a 180-degree angle) was performed on this laminated plate, and the peel strength of 7.8 kg / 2 cm (adhesive force per 2 cm width) in the center part was gotten. The results are shown in the table below.

Example 2 A vinylidene fluoride-aluminum laminate was obtained in the same manner as in Example 1 except that 0.8 part by weight of vinyltrimethoxysilane was used. When this laminated plate was subjected to a 180-degree peel test in the same manner as in Example 1, a peel strength of 4.5 kg / 2 cm was obtained in the central portion. The results are shown in the table below.

Example 3 A vinylidene fluoride-aluminum laminate was obtained in the same manner as in Example 1 except that 0.8 parts by weight of vinyltrimethoxysilane and the irradiation dose of γ-rays were 3.0 megarads. About this laminated plate, by the same method as in Example 1.
When a 180-degree peel test was performed, a peel strength of 5.2 kg / 2 cm was obtained at the center. The results are shown in the table below.

Example 4 A vinylidene fluoride-aluminum laminate was obtained in the same manner as in Example 1 except that the irradiation dose of gamma rays was 3.0 megarads. A 180-degree peeling test was conducted on this laminated plate by the same method as in Example 1, and it was found that the central portion had a value of 8.0.
A peel strength of kg / 2 cm was obtained. The results are shown in the table below.

Comparative Example 1 An attempt was made to produce a vinylidene fluoride-aluminum laminate in the same manner as in Example 1 except that the gamma ray was not irradiated. However, the vinylidene fluoride resin did not adhere to the aluminum plate at all. The results are shown in the table below.

Comparative Example 2 Except that vinyltrimethoxysilane was not used,
A vinylidene fluoride-aluminum laminate was obtained in the same manner as in Example 1. A 180-degree peel test was conducted on this laminated plate by the same method as in Example 1, and
Only a peel strength of 0.6 kg / 2 cm was obtained. The results are shown in the table below.

Comparative Example 3 Except that vinyltrimethoxysilane was not used,
A vinylidene fluoride-aluminum laminate was obtained in the same manner as in Example 3. A 180-degree peel test was conducted on this laminated plate by the same method as in Example 1, and
Only a peel strength of 0.7 kg / 2 cm was obtained. The results are shown in the table below.

Example 5 A vinylidene fluoride-aluminum laminate was obtained in the same manner as in Example 1 except that a chemical conversion treatment liquid (Bondelite ^# 713, manufactured by Nippon Parkerizing Co., Ltd.) was used instead of the sodium hydroxide solution. A 180-degree peel test was conducted on this laminated plate in the same manner as in Example 1, and a peel strength of 8.3 kg / 2 cm was obtained in the central portion.

Example 6 A vinylidene fluoride-iron laminate was obtained in the same manner as in Example 1 except that an iron plate having a thickness of 0.15 mm was used in place of the aluminum plate and treated with a 10% nitric acid solution. A 180-degree peel test was conducted on this laminated plate in the same manner as in Example 1, and a peel strength of 5.5 kg / 2 cm was obtained at the central portion.

Example 7 A vinylidene fluoride-copper laminate was obtained in the same manner as in Example 1 except that a 0.10 mm thick copper plate was used in place of the aluminum plate and was treated with a 10% nitric acid solution. When this laminated plate was subjected to a 180-degree peel test in the same manner as in Example 1, a peel strength of 5.6 kg / 2 cm was obtained in the central portion.

Example 8 A γ-ray-irradiated vinylidene fluoride resin mixture obtained in the same manner as in Example 1 was used at a temperature of a cylinder part of 230 ° C. and a mold of 210 ° C. to produce a single-screw extruder having a diameter of 65φ (width: 150 mm, thickness: Extruded using a fishtail die with a 0.6 mm opening). The extruded film-like melt was placed on a strip-shaped aluminum plate (aluminum ^# 5052, Sumitomo Light Metals Co., Ltd., thickness 0.2 mm, width 200 mm) that had been preheated to 230 ° C using the pressure roll device shown in the figure. Continuously coated and crimped. When crimped at a crimping speed of 3 m / min, the thickness is 0.
A vinylidene fluoride-aluminum laminate having a 5 mm vinylidene fluoride resin layer was obtained. A 180-degree peel test was conducted on the central portion of this laminate and a portion 40 mm from the edge by the same method as in Example 1, and
A peel strength of 7.5 kg / 2 cm and a peel strength of 4.1 kg / 2 cm was obtained at a portion 40 mm from the edge.

Example 9 Mica (suzolite mica) was added to 100 parts by weight of vinylidene fluoride resin in the γ-irradiated vinylidene fluoride resin mixture.
^A vinylidene fluoride-aluminum laminate was obtained in the same manner as in Example 8 except that 10 parts by weight of ^# 200H, manufactured by Kuraray Co., Ltd.) was added. A 180-peel test was performed on the central portion of this laminate and a portion 40 mm from the edge by the same method as in Example 1, and found to be 7.3 kg / 2 cm at the central portion and 40
A peel strength of 5.8 kg / 2 cm was obtained in the mm portion.

Example 10 A mixture of γ-ray-irradiated vinylidene fluoride resin and 100 parts by weight of vinylidene fluoride resin was treated with mica (szolite mica
^# 200H, manufactured by Kuraray Co., Ltd.) A vinylidene fluoride-aluminum laminate was obtained in the same manner as in Example 8 except that 30 parts by weight was added. A 180-degree peel test was conducted on the central portion of this laminated plate and a portion 40 mm from the edge by the same method as in Example 1. As a result, 7.0 kg / 2 cm at the central portion and from the edge
A peel strength of 6.9 kg / 2 cm was obtained at the 40 mm portion.

As is clear from the examples and comparative examples, the vinylidene fluoride-based composite material of the present invention has good adhesiveness to the metal substrate and shows a high value even in the 180-degree peeling test. By pre-treating the surface of the metal substrate, the adhesiveness is further improved. In addition, the composite material containing mica is
Adhesion near the edges is significantly improved. The vinylidene fluoride-based composite material, which was not irradiated with γ-rays, did not contain vinyltrimethoxysilane.
No or little adhesion to metal substrates.

(Effects of the Invention) The vinylidene fluoride-based composite material of the present invention is thus
It can be easily obtained and has good adhesion between the vinylidene fluoride resin and the metal substrate. Therefore, the corrosion resistance of the metal is improved. The composite material of the present invention can therefore be effectively used for metal protection of products used outdoors such as household appliances.

[Brief description of drawings]

The figure is an explanatory view showing one embodiment of an apparatus used for producing the composite material of the present invention. 1 ... Single screw extruder, 2 ... Molten vinylidene fluoride resin, 3 ...
… Strip aluminum plate, 4 …… Crimping roll, 10 …… Fishtail die.

Claims (13)

[Claims] 1. A vinylidene fluoride-based composite material obtained by coating a metal substrate with a composition containing a vinylidene fluoride resin previously irradiated with ionizing radiation and an organic silicon compound represented by the following formula. Here, R is an olefinic hydrocarbon group, Y is a hydrolyzable organic group, and R'is R or Y. 2. The vinylidene fluoride-based composite material according to claim 1, wherein the organosilicon compound is contained in an amount of 0.1 to 10 parts by weight with respect to 100 parts by weight of the vinylidene fluoride resin. 3. The vinylidene fluoride-based composite material according to claim 1, wherein the dose of the ionizing radiation is 0.1 megarad or more. 4. The vinylidene fluoride-based composite material according to claim 1, wherein the organosilicon compound is at least one of vinyltrimethoxysilane and vinyltriethoxysilane. 5. The ionizing radiation comprises β rays, γ rays, α rays,
The vinylidene fluoride-based composite material according to claim 1, which is at least one of neutron rays, X-rays, and accelerated electron rays. 6. A metal substrate is coated with a composition containing vinylidene fluoride resin pre-irradiated with ionizing radiation, an organosilicon compound represented by the following formula, and an organic filler and / or an inorganic filler. Vinylidene fluoride composite material. Here, R is an olefinic hydrocarbon group, Y is a hydrolyzable organic group, and R'is R or Y. 7. The vinylidene fluoride-based composite material according to claim 6, wherein the organosilicon compound is contained in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the vinylidene fluoride resin. 8. The vinylidene fluoride-based composite material according to claim 6, wherein the dose of the ionizing radiation is 0.1 megarad or more. 9. The vinylidene fluoride-based composite material according to claim 6, wherein the organosilicon compound is at least one of vinyltrimethoxysilane and vinyltriethoxysilane. 10. The ionizing radiation comprises β rays, γ rays, and α rays.
7. The vinylidene fluoride-based composite material according to claim 6, which is at least one of a ray, a neutron ray, an X-ray, and an accelerated electron beam. 11. The organic filler and / or the inorganic filler is added to 30 parts by weight with respect to 100 parts by weight of the vinylidene fluoride resin.
The vinylidene fluoride-based composite material according to claim 6, which is contained in a proportion of 0 parts by weight or less. 12. The organic filler is powder of thermosetting resin such as phenol resin or melamine resin, carbon fiber,
7. The vinylidene fluoride-based composite material according to claim 6, which is at least one of organic fibers such as aramid fibers, graphite and wood flour. 13. The method according to claim 6, wherein the inorganic filler is at least one of inorganic fine powder such as talc, mica and calcium carbonate, inorganic fiber such as potassium titanate fiber and glass fiber. Vinylidene fluoride composite material.