JP2002370321A - Heat contact-bonding conductive film, conductive synthetic resin material using the film, and molded product of conductive synthetic resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat contact-bonding conductive film which a conductive layer containing an ionizing radiation-curable resin, and can be bonded to a synthetic resin material by heat contact bonding and easily finished with any kind of synthetic material, plane, curved or complicatedly shaped, with the capability of imparting desired conductive properties. SOLUTION: An anchor coat layer containing the ionizing radiation-curable resin is formed on a heat meltable synthetic resin film 11. In addition, a conductive layer 12 containing conductive particles and the ionizing radiation-curable resin is formed on he anchor coat layer. Thus the heat contact-bonding conductive film 10 is constituted. The conductive layer 11 contains 50 to 90 wt.% of the conductive particle. Further, the synthetic resin film 11 which is the heat contact-bonding conductive film 10 is thermally pressurized into a molded product 40 of a conductive synthetic resin using a mold 30 of a specified shape, under such a state that the synthetic resin film 11 is kept in contact with at least one of the sides of a synthetic resin material 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive film for imparting conductivity to a synthetic resin material such as a plastic plate, and more particularly to a thermocompression conductive film adhered to a synthetic resin material by thermocompression.

[0002]

2. Description of the Related Art A synthetic resin plate subjected to an antistatic treatment is used as a structural material of a wall surface or a floor surface of a room such as an industrial dust-free room (clean room) which dislikes fine powder. Such a conductive synthetic resin plate is also used in the field of microelectronics as a dustproof container or a shielding member used in a solid circuit manufacturing and assembling process. As an antistatic treatment method for a synthetic resin plate, there is a method in which a coating liquid composed of a thermoplastic resin and a conductive fine powder is applied to a synthetic resin plate and cured, and then pressed under heating to smooth the coating film surface. However, in such a method, there is a problem that the surface resistance value of the obtained synthetic resin plate varies depending on the location, and the quality is varied.

On the other hand, a method using a conductive film in which a conductive film is formed on a release film in advance is also known (Japanese Patent Application Laid-Open Nos. 6-263899 and 9-226044). In these methods, the synthetic resin plate and the conductive film are heated and pressed between press dies, and then the release film is peeled off to form a conductive coating layer on the surface of the synthetic resin plate.

In order to increase the hardness and scratch resistance of the conductive layer, an antistatic film in which a conductive layer containing a UV-curable resin is formed on a transparent support has been proposed (Japanese Patent Laid-Open No. Hei 10 (1998)).
-235807). This antistatic film is used by bonding the transparent support side to a synthetic resin plate via an adhesive layer, and imparts conductivity to the synthetic resin plate.

[0005]

However, when an antistatic film provided with a conductive ultraviolet curable resin layer is bonded via an adhesive layer, there is a limitation on the shape of the object to be bonded.
That is, when the synthetic resin plate is flat, it can be easily adhered. However, when the synthetic resin plate has a curved surface or a complicated shape, the adhesion between the synthetic resin plate and the antistatic film can be improved. Poor performance, air in between, adversely affects performance such as conductivity and durability.

On the other hand, thermocompression bonding of a conductive ultraviolet curable resin layer is conceivable. However, a layer in which a conductive material is added to the ultraviolet curable resin has a reduced hardness, so that cracks occur during thermocompression bonding. there is a possibility. When cracks occur, not only the appearance is impaired, but also the desired conductivity cannot be obtained.

Accordingly, an object of the present invention is to provide a thermocompression bonding conductive film which has a conductive layer containing an ionizing radiation-curable resin and can be bonded to a synthetic resin material by thermocompression bonding. Accordingly, it is an object of the present invention to provide a thermocompression-bonding conductive film which can easily provide a desired conductivity even if it is a synthetic resin material having a curved surface or a complicated shape as well as a flat surface. Another object of the present invention is to provide a thermocompression-bondable conductive film that prevents cracking that occurs when a layer of an ionizing radiation-curable resin is thermocompressed.

[0008]

According to the present invention, there is provided a thermocompression-bonding conductive film which comprises a heat-fusible synthetic resin film and an ionizing radiation-curable resin, and is formed on the synthetic resin film. And a conductive layer formed on the anchor coat layer, the conductive layer including conductive particles and an ionizing radiation-curable resin.

In the thermocompression-bonding conductive film of the present invention, the synthetic resin film and the synthetic resin material are integrated by applying heat and pressure in a state where the heat-fusible synthetic resin film is in contact with the synthetic resin material. A synthetic resin material on the surface of which a conductive layer containing an ionizing radiation-curable resin is formed can be obtained. Therefore, molding of the synthetic resin material and imparting of conductivity can be performed in the same step. Further, by providing the anchor coat layer between the conductive layer and the synthetic resin film, it is possible to prevent the conductive layer from cracking during thermocompression bonding.

[0010] The conductive synthetic resin material of the present invention is produced using the thermocompression-bonding conductive film. Specifically, at least one surface of the synthetic resin material to be provided with conductivity is provided. And a thermocompression bonding method in which the synthetic resin film of the thermocompression conductive film is brought into contact with the thermocompression conductive film. Further, the conductive synthetic resin molded product of the present invention is heated and pressed with a mold having a predetermined shape in a state where the synthetic resin film of the thermocompression conductive film is in contact with at least one surface of the synthetic resin material. It becomes.

Hereinafter, the thermocompression bonding conductive film of the present invention will be described in detail. The synthetic resin film used for the thermocompression bonding conductive film of the present invention is made of a heat-fusible synthetic resin.
Examples of the heat-fusible synthetic resin include acrylic resins such as polycarbonate, polyolefin, polyester, and polyacrylate, and resins such as polyvinyl chloride and polyvinylidene chloride. Among these, polycarbonate, polyvinyl chloride, and acrylic resin are preferred, and polycarbonate is particularly preferred because of its excellent mechanical strength.

Although the thickness of the synthetic resin film is not particularly limited, it is usually about 50 to 300 μm. By setting the content in such a range, the handleability and the workability during thermocompression bonding are improved.

The anchor coat layer is a layer containing an ionizing radiation-curable resin. The ionizing radiation-curable resin is a resin that is cross-linked and cured by irradiation with ionizing radiation (ultraviolet light or electron beam), such as a resin having an acrylic group such as an epoxy acrylate, a polyester acrylate, a polyurethane acrylate, and a polyhydric alcohol acrylate, and a polythiol. A photopolymerizable prepolymer such as a polyene resin can be used.

These can be used alone, but it is preferable to add a photopolymerizable monomer in order to improve the cross-linking curability and the hardness of the cross-linked cured film. Examples of the photopolymerizable monomer include monofunctional acrylic monomers such as 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and butoxyethyl acrylate, 1,6-hexanediol acrylate, neopentyl glycol diacrylate, and diethylene glycol diacrylate. One or two kinds of bifunctional acrylic monomers such as acrylate, polyethylene glycol diacrylate and hydroxypivalate neopentyl glycol acrylate, and polyfunctional acrylic monomers such as dipentaerythritol hexaacrylate, trimethylpropane triacrylate and pentaerythritol triacrylate The above is used.

In the case where the anchor coat layer is cured by irradiation with ultraviolet rays, it is preferable to add a photopolymerization initiator, an ultraviolet sensitizer and the like, in addition to the above-mentioned photopolymerizable prepolymer and photopolymerizable monomer. As the photopolymerization initiator,
Radical photopolymerization initiators such as benzoin ether, ketal, acetophenone, thioxanthone, diazonium salts, diaryliodonium salts, triarylsulfonium salts, triarylbilium salts, benzylpyridinium thiocyanates, dialkylphenacylsulfonium salts, dialkyl A hydroxyphenylsulfonium salt, a dialkylhydroxyphenylphosphonium salt, or the like, a composite cationic photopolymerization initiator, or the like can be used.

Further, the anchor coat layer may contain a resin other than the ionizing radiation-curable resin in order to improve the adhesion to the synthetic resin film. As such a resin, for example, a thermosetting or thermoplastic acrylic resin,
Epoxy resin or the like can be used. However, in order to prevent cracking during thermocompression bonding, the content of ionizing radiation-curable resin is 90% by weight of the resin constituting the anchor coat layer.
It is preferable that it is above.

Further, in addition to the ionizing radiation-curable resin and the like, additives such as a UV absorber and a light stabilizer may be contained.

The conductive layer contains an ionizing radiation curable resin and conductive particles. As the ionizing radiation-curable resin, the same resins as those mentioned as the resin for the anchor coat layer can be used.

Examples of the conductive particles include fine powders of metals such as aluminum and zinc, fine powders of metal oxides such as fine powders of titanium oxide, zinc oxide, tin oxide and indium oxide, and fine powders of a mixture of tin oxide and antimony oxide. For example, tin oxide doped with antimony can be used. Needle-like conductive particles in which the surface of a needle-like substance is coated with a metal or a metal oxide may be used. Examples of the acicular conductive particles include particles in which the surface of acicular potassium titanate is extremely thinly coated with aluminum, chromium, silver, antimony, indium, tin oxide doped with antimony oxide, or the like. In applications where transparency is required, fine oxide powder such as tin oxide or a mixture of tin oxide and antimony oxide is suitable. These can be used alone or in combination of two or more.

The particle size of the conductive particles is preferably 0.2 μm or less. By using particles having a size of 0.2 μm or less, scattering of visible light can be suppressed and transparency can be ensured.

The amount of the conductive particles is preferably 50 to 90% by weight, more preferably 60 to 85% by weight of the conductive layer (the whole material constituting the conductive layer). By adding 50% by weight or more, the surface resistivity of the material after the conductive layer is compressed is 10 ⁴ to 10 ⁹
Ω, and can be applied to applications requiring extremely high antistatic properties. When the acicular conductive particles are used, the above surface resistivity can be obtained even when the addition amount is about 35% by weight or more. When the content is 90% by weight or less, a decrease in the strength of the coating film can be prevented, and the transparency can be maintained.

The conductive layer may be made of, in addition to the above-mentioned ionizing radiation-curable resin and the conductive particles, a UV layer as long as the conductivity is not impaired.
Additives such as absorbers and light stabilizers can be included.

The thermocompression-bonding conductive film having such a constitution contains a photopolymerizable prepolymer and a photopolymerizable monomer, and optionally contains a photopolymerization initiator and an ultraviolet sensitizer. After applying the mold resin paint on the synthetic resin film, irradiating ultraviolet rays or electron beams to form an anchor coat layer, and further applying an ionizing radiation-curable paint containing conductive particles on the anchor coat layer, It can be manufactured by irradiating an ultraviolet ray or an electron beam to form a conductive layer.

The thickness of the anchor coat layer is preferably 2 μm.
m, more preferably 4 to 12 μm. The thickness of the conductive layer is preferably 1.0 to 5.0 μm, more preferably 1.5 to 3 μm.
m. By setting the thickness of each layer within the above range, cracking during thermocompression bonding can be effectively prevented, and sufficient surface hardness can be obtained. Further, by setting the thickness of the conductive layer in the above range, the surface resistivity of the material after pressure bonding can be in the range of 10 ⁴ to 10 ⁹ Ω.

The conductive synthetic resin material of the present invention can be manufactured by thermocompression bonding the above-mentioned thermocompression-bonding conductive film to at least one surface of the synthetic resin material. This is illustrated in FIG. In this example, a pair of thermo-compression conductive films 10 is used to sandwich the synthetic resin plate 20 so that the synthetic resin film 11 and the synthetic resin plate 20 are in contact with each other. The synthetic resin film 12 and the synthetic resin plate 20 are thermocompression-bonded by applying heat and pressure with a hot press plate 30 to form a conductive synthetic resin material 40. In the drawing, the anchor coat layer is omitted.

Here, the synthetic resin plate 20 is shown as a flat plate. However, even if the synthetic resin plate 20 has a curved surface or a step, the same shape can be used as the press plate 30 to similarly produce a heat. The press-bondable conductive film 10 can be thermo-pressed. Alternatively, by using a flat plate as the synthetic resin plate 20 and using a press plate 30 having a desired shape, the synthetic resin plate 20 can be formed simultaneously with the thermocompression bonding of the thermocompression conductive film 10. Thus, a conductive synthetic resin molded product 40 can be obtained.

The material of the synthetic resin plate is not particularly limited, but it is preferable to use a synthetic resin which can be melted by heat as in the case of the synthetic resin film of the thermocompression conductive film. Thereby, the conductive synthetic resin material is completely adhered to the synthetic resin film 11 and has excellent durability.

The conditions for thermocompression bonding differ depending on the material of the synthetic resin film and the synthetic resin plate, but are usually at 60 to 250 ° C.
By heating and pressing for 0 to 120 minutes, both can be melted and bonded.

As described above, the conductive synthetic resin material of the present invention can be used as a material for floors and walls of a clean room, as a material for pallets and various cases used in a clean room, and generally has an antistatic function. Can be used for applications requiring

[0030]

EXAMPLES Hereinafter, the thermocompression-bonding conductive film of the present invention will be further described based on examples. In the following examples, “%” and “parts” mean “% by weight” and “parts by weight”, respectively, unless otherwise specified.

Example 1 One side of a polycarbonate film (250 μm thick) was coated with a coating liquid for an anchor coat layer having the following formulation, dried, and irradiated with ultraviolet rays (120 W) for 10 minutes to form a film having a thickness of 6.5 μm. An anchor coat layer was formed.

<Coating liquid for anchor coat layer> 47 parts of ionizing radiation-curable resin (solid content 80% by weight) (Unidick 17-806: Dainippon Ink and Chemicals, Inc.) 1.1 parts of photopolymerization initiator (Irgacure 184: Chemical Specialty Chemicals Co., Ltd.) 34 parts of propylene glycol monomethyl ether 17 parts of toluene

A coating liquid for a conductive layer having the following formulation was applied on the anchor coat layer, dried, and irradiated with ultraviolet rays (120 W) for 2 hours.
Irradiation was performed for 0 minutes to form a conductive layer having a thickness of 2.8 μm to obtain a thermocompression-bonding conductive film.

<Coating solution for conductive layer> Tin dioxide-antimony pentoxide 10.4 parts Ionizing radiation curable resin 3.3 parts (solid content 80% by weight) (Unidick 17-813: Dainippon Ink and Chemicals, Inc.)・ Industrial Co., Ltd. ・ Photopolymerization initiator 0.08 parts (Irgacure 184: Tiha Chemical Chemicals) ・ Propylene glycol monomethyl ether 12.8 parts ・ Toluene 38.5 parts

The synthetic resin film side of the obtained thermocompression conductive film is placed on a separately prepared 2 mm-thick polycarbonate plate and placed on a pair of upper and lower hot plates at a pressure of 30 kg.
Pressure was applied at a temperature of 180 ° C./cm ^{2 for} 40 minutes to obtain a conductive synthetic resin material.

Example 2 A thermocompression conductive film was obtained in the same manner as in Example 1 except that a vinyl chloride sheet (thickness: 100 μm) was used as a synthetic resin film. The synthetic resin film side of the obtained thermocompression-bonding conductive film is placed on a separately prepared 5 mm thick vinyl chloride plate and placed on a pair of upper and lower hot plates at a pressure of 20 kg / cm ^{2 at} a temperature of 180 ° C. The mixture was squeezed for minutes to obtain a conductive synthetic resin material.

Example 3 One side of a polycarbonate film (250 μm in thickness) was coated with the same coating solution for anchor coat layer as in Example 1, dried, and irradiated with ultraviolet rays (120 W) for 10 minutes to form a film having a thickness of 3.5 μm. A μm anchor coat layer was formed. A coating liquid for a conductive layer having the following formulation was applied on the anchor coat layer, dried, and then irradiated with ultraviolet rays (120 W) for 20 minutes to obtain a thickness of 3.
A 6 μm conductive layer was formed to obtain a thermocompression conductive film.

<Coating solution for conductive layer>-8.5 parts of tin dioxide-antimony pentoxide-5.6 parts of ionizing radiation-curable resin (solid content: 80% by weight) (Unidick 17-813: Dainippon Ink and Chemicals, Inc.)・ Industrial Co., Ltd. ・ Photopolymerization initiator 0.08 parts (Irgacure 184: Tiha Chemical Chemicals) ・ Propylene glycol monomethyl ether 12.8 parts ・ Toluene 38.5 parts

The synthetic resin film side of the obtained thermocompression-bonding conductive film is placed on a separately prepared 2 mm-thick polycarbonate plate and placed under a pressure of 30 kg using a pair of upper and lower hot plates.
Pressure was applied at a temperature of 180 ° C./cm ^{2 for} 40 minutes to obtain a conductive synthetic resin material.

Example 4 A thermocompression conductive film was obtained in the same manner as in Example 3 except that a vinyl chloride sheet (thickness: 100 μm) was used as the synthetic resin film. The synthetic resin film side of the obtained thermocompression-bonding conductive film is placed on a separately prepared 5 mm thick vinyl chloride plate and placed on a pair of upper and lower hot plates at a pressure of 20 kg / cm ^{2 at} a temperature of 180 ° C. The mixture was squeezed for minutes to obtain a conductive synthetic resin material.

Comparative Example 1 The same conductive layer coating solution as in Example 3 was directly applied without providing an anchor coat layer on one side of a polycarbonate film (250 μm thick), and dried.
Ultraviolet light (120 W) was irradiated for 20 minutes to form a conductive layer having a thickness of 3.6 μm, and a thermocompression conductive film was obtained. The synthetic resin film side of the obtained thermocompression-bonding conductive film is placed on a separately prepared 2 mm-thick polycarbonate plate and placed on a pair of upper and lower hot plates at a pressure of 30 kg / cm ² and a temperature of 180 ° C. at 40 ° C.
The mixture was squeezed for minutes to obtain a conductive synthetic resin material.

Comparative Example 2 A thermocompression-bonding conductive film having no anchor coat layer was obtained in the same manner as in Comparative Example 1 except that a vinyl chloride sheet (thickness: 100 μm) was used as a synthetic resin film. The synthetic resin film side of the obtained thermocompression-bonding conductive film is placed on a separately prepared 5 mm-thick vinyl chloride plate and placed under a pressure of 20 kg using a pair of upper and lower hot plates.
Pressure was applied at a temperature of 180 ° C./cm ^{2 for} 40 minutes to obtain a conductive synthetic resin material.

Comparative Example 3 A coating liquid for a conductive layer having the following formulation was directly applied without providing an anchor coat layer on one side of a polycarbonate film (250 μm in thickness). Irradiation to form a conductive layer having a thickness of 3.6 μm, thereby obtaining a thermocompression-bonding conductive film.

<Coating solution for conductive layer>-5.2 parts of tin dioxide-antimony pentoxide-9.7 parts of ionizing radiation-curable resin (solid content: 80% by weight) (Unidick 17-813: Dainippon Ink and Chemicals, Inc.)・ Industrial Co., Ltd. ・ Photopolymerization initiator 0.08 parts (Irgacure 184: Tiha Chemical Chemicals) ・ Propylene glycol monomethyl ether 12.8 parts ・ Toluene 38.5 parts

The synthetic resin film side of the obtained thermocompression-bonding conductive film is placed on a separately prepared 2 mm-thick polycarbonate plate and placed under a pressure of 30 kg using a pair of upper and lower hot plates.
Pressure was applied at a temperature of 180 ° C./cm ^{2 for} 40 minutes to obtain a conductive synthetic resin material.

With respect to the conductive synthetic resin materials obtained in the above Examples and Comparative Examples, the surface resistivity (Ω) was measured, and cracks (cracks of the coating film) after thermocompression bonding were observed.
Table 1 shows the results.

[0047]

[Table 1]

As can be seen from the results shown in Table 1, the synthetic resin materials of Comparative Examples 1 and 2 having no anchor coat layer cause cracks in the coating film during thermocompression bonding, thereby forming the same conductive layer as in the example. Despite the formation, an increase in surface resistivity was observed. Although the synthetic resin material of Comparative Example 3 was not provided with the anchor coat layer, the content of the conductive particles in the conductive layer was low, so that the coating film did not crack, but was sufficient to obtain the antistatic effect. Conductivity could not be obtained.

[0049]

According to the present invention, thermocompression bonding is achieved by using a heat-fusible synthetic resin film as a base material and providing a layer containing an ionizing radiation-curable resin between the synthetic resin film and the conductive layer. Accordingly, it is possible to provide a conductive film that can be pressure-bonded to an arbitrary synthetic resin material and that does not have a decrease in conductivity due to cracking during thermocompression bonding. Further, according to the present invention, it is possible to form a scratch-resistant conductive surface on the synthetic resin material in the same step as the molding of the synthetic resin material.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a method for producing a conductive synthetic resin material according to the present invention.

[Explanation of symbols]

 10 ... conductive film 11 ... synthetic resin film 12 ... conductive layer 20 ... synthetic resin plate 40 ... synthetic resin molded product

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hitoshi Onuma 2-1-15 Midoricho, Kanuma City, Tochigi Prefecture Hi Maison Sagami 201 (72) Inventor Soichiro Hashimoto 2270-1 Moro, Kanuma City, Tochigi Prefecture Royal Heights Room 201 F-term ( Reference) 4F100 AA17C AA28 AA29 AK01A AK01B AK01C AK15A AK25A AK45A BA03 BA07 BA10A BA10C CA21C CC02B CC02C EJ17 EJ42 GB07 JB16A JG01C YY00C 4J002 AA021 CD001 CF001 CH001 CK02100 GT001

Claims (6)

[Claims] 1. An anchor comprising a heat-fusible synthetic resin film, an ionizing radiation-curable resin, an anchor coat layer formed on the synthetic resin film, conductive particles and an ionizing radiation-curable resin. A thermocompression-bondable conductive film, comprising: a conductive layer formed on a coat layer. 2. The thermocompression-bondable conductive film according to claim 1, wherein the conductive layer contains 50 to 90% by weight of the conductive particles. 3. The thermocompression-bondable conductive film according to claim 2, wherein the conductive particles are metal oxides. 4. The thermocompression-bondable conductive film according to claim 1, wherein the synthetic resin film is made of a resin selected from polycarbonate, polyvinyl chloride, and acrylic resin. 5. An electrically conductive composite obtained by contacting at least one surface of a synthetic resin material with the synthetic resin film of the thermocompression conductive film according to claim 1 and thermocompression bonding. Resin material. 6. A mold having a predetermined shape in a state where the synthetic resin film of the thermocompression conductive film according to any one of claims 1 to 4 is brought into contact with at least one surface of the synthetic resin material. A conductive synthetic resin molded product heated and pressurized in.