JP2008119675A - Method for coating substrate of poor cohesiveness and poor adhesiveness with water-based coating material comprising polyurethane resin, and substrate of poor cohesiveness and poor adhesiveness coated by this method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for coating a substrate of poor cohesiveness and poor adhesiveness with a water-based coating material comprising a polyurethane resin, and a substrate of poor cohesiveness and poor adhesiveness coated by this method. <P>SOLUTION: The coating method comprises the step of introducing a gasified modifier comprising a silicon atom or the like having a boiling temperature of 10°C to 105°C as it remains gaseous and combustion air into fuel gas in such a manner that the air/hydrocarbon mole ratio in the combustion gas is kept not lower than 23, burning thus prepared combustion gas to form a flame of the fuel gas, treating the surface of the substrate of poor cohesiveness and poor adhesiveness by applying the flame onto it to activate the surface so that its wetting index becomes 73 dyn/cm or higher, and subsequently coating the treated substrate with a water-based coating material comprising a urethane resin, whereby the substrate of poor cohesiveness and poor adhesiveness can be directly coated with the water-based coating material comprising a urethane resin with high cohesion and adhesion strength without requiring a commonly practiced pretreatment with a primer as cohesive and adhesive aids. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a coating / coating method of a water-based polyurethane resin coating material for a difficult-to-adhere / hard-adhesive plastic-based substrate, and a difficult-to-adhere / hard-adhesive substrate coated / coated by the same method, In particular, thermoplastic elastomers such as polyester-based thermoplastic elastomers, olefin-based thermoplastic elastomers, styrene-based thermoplastic elastomers, or other elastomers other than those typified by natural rubber, silicon rubber, etc. Direct application of water-based polyurethane resin to various flexible elastomeric substrates, which are said to be difficult to adhere, without any pre-priming treatment that is usually used as a standard adhesion and adhesion aid. A method of painting and coating materials with high adhesion and high adhesion, as well as difficult adhesion and adhesion that are painted and coated by the same method On the base material.

  In recent years, the so-called “Sick House Syndrome” problem has frequently occurred in apartment buildings, and in facilities such as museums, there has been a problem of deterioration or damage of cultural assets due to ammonia gas, etc. The problem of environmental pollutants (outgas) emitted from paints applied to the surface of various materials such as various building materials or various household appliances, etc. Volatile organic compounds (VOC) represented by toluene, xylene, and ethyl acetate are legally regulated because they have a significant impact on human health. It is in the situation that has led to.

  Due to the above-mentioned social background, paints applied to various building materials and various residential equipment or various household electrical appliances and various equipment materials are rapidly changed to solvent-free types that generate very little human-friendly outgas. There is a situation where the usage of paint is changing rapidly. In light of such a social background, in the paint industry, it is an urgent task to make various solvent-based paints and coating materials water-based.

  By the way, in the case of paints that are water-based or water-based, it is difficult to ensure adhesion and adhesion to various equipment materials compared to paints that are generally solvent-based, so as to ensure adhesion and adhesion performance. In addition, it is customary to select appropriate primers suitable for various base materials or to develop new ones depending on the conditions. Adhesion / adhesion between various base materials and water-based urethane paints is sufficient even under conditions using existing primers. Ensuring is recognized as a technically difficult and difficult problem. In particular, among various plastic materials, for thermoplastic elastomers such as polyester-based thermoplastic elastomers, olefin-based thermoplastic elastomers, styrene-based thermoplastic elastomers, or other elastomers such as natural rubber and silicon rubber. However, since the base material itself is flexible and has the property that the base material itself can be freely deformed, the shearing force acts between the base material and the coating film to be flexible. Even in the case of urethane-based coating materials (paints) having the properties, it has been extremely difficult to ensure a high degree of adhesion and adhesion of the water-based paint to the base material, and improvement thereof has been strongly desired. Against this background, establishing a coating / coating method on the premise of ensuring reliable adhesion / adhesion of water-based paints (coating materials) to various elastomer materials has been an urgent issue.

By the way, the present inventor has already developed and put into practice a general “solid interface reforming method” that improves the surface of various solid substances to ensure adhesion and adhesion of paints and adhesives. The details are disclosed in the following document.
JP 2003-238710 (Patent No. 3557194)

  The above-mentioned “Patent Document 1” discloses an outline of an interface reforming method and apparatus for a solid substance, which is an interface modifier compound containing a silane atom, a titanium atom, and an aluminum atom, each having a boiling point of 10 A storage tank for storing a fuel gas containing an interfacial modifier compound having a temperature of from 100 ° C. to 100 ° C., a transfer unit for transferring the fuel gas to the injection unit, and an injection unit for blowing a flame of the fuel gas An interface reforming device including a (burner), and spraying a silicic acid flame or the like entirely or partially on the material interface of the solid substance to modify and activate the processing section A reforming technique is disclosed.

  However, Patent Document 1 only describes an interface modification method common to various solid substances for interfacial modification of solid substances that can be substituted for conventional corona treatment, primer treatment, flame treatment, and the like. Specific problems to be solved, that is, specifics on the coating and coating methods on the premise of ensuring reliable adhesion and adhesion of water-based urethane paints and coating materials to various elastomer materials that were said to be particularly difficult to solve Naturally, no technical technique or methodology is disclosed at all.

  The present invention relates to polyethylene (PE) resin, polyolefin resin represented by polypropylene (PP) resin, polyamide (PA) resin, and polyethylene terephthalate (PET), which are generally referred to as difficult adhesion / hard adhesion resin. Resin, polycarbonate (PC) resin, polyphenylene ether (PPE) resin, general-purpose engineering resin typified by polybutylene terephthalate (PBT) resin, polyphenylene sulfide (PPS) resin, polyamideimide (PAI) resin, polytetra Super engineering resins such as fluoroethylene (PTFE) resin, polyester-based thermoplastic elastomers, olefin-based thermoplastic elastomers, styrene-based thermoplastic elastomers, etc. The water-based urethane resin is placed on one hardly-adhesive / hard-adhesive thermoplastic base material selected from various plastic base materials composed of plastic elastomer, natural rubber, other elastomers typified by silicon rubber, and the like. By utilizing the “surface modification method for solid substances” proposed by the present patent applicant as disclosed in Patent Document 1, it is possible to perform pre-adhesion / adhesion treatment such as primer treatment that has been generally performed in the past. There is a proposal of a method that can achieve high adhesion or high adhesion without fail.

  Before describing the present invention in detail, first, the surface of a plastic substrate represented by each resin such as an olefin resin or a polyester terephthalate (PET) resin, which is said to be a difficult adhesion / hard adhesion substrate. First, an outline of “Patent Document 1: Japanese Patent Application Laid-Open No. 2003-238710 (Patent No. 3557194)”, which is an “interface reforming technology” for reforming an interface to an easily adhesive / adhesive interface will be described first. .

FIG. 1 is a flowchart for explaining an outline of an interface reforming apparatus according to the present invention, which will be described based on the flowchart.
1 is an interface modifier compound containing silane atoms, titanium atoms, and aluminum atoms, and includes an alkylsilane compound, an alkoxysilane compound, a siloxane compound, a silazane compound, and an alkyl titanium. A storage tank portion 102 for storing an interfacial modifier compound 101 selected from the group consisting of a compound, an alkoxytitanium compound, an alkylaluminum compound, and an alkoxyaluminum compound; and a jetting portion (burner) that is vaporized by a heating means 103 ) A transfer path 105 for transferring to 104, a fuel gas storage tank 106 such as propane gas and LPG gas, and air for conveying the fuel gas combustion air and the interface modifier compound are supplied. And a compressed air source 107. A first sub-mixer 108 is also provided in the transfer path 105 for uniformly mixing the vaporized interface modifier compound and air mixed gas and the fuel gas delivered from the storage tank 106. The second main mixer 109 is configured. Further, the delivery tanks 102 for storing the interfacial modifier compound 101, the compressed air source 107 for supplying air, and the delivery destination outlets of the fuel gas storage tank 106 have respective delivery flow rates. Flow control valves with flowmeters 110, 111, and 112 for control are provided, respectively, to constitute the interface reformer 100. Next, the detail of each said main structural member (part) is demonstrated.

"Storage tank for interfacial modifier compound"
As shown in FIG. 1, a heating means 103 such as a heater for heating is provided below the interfacial modifier compound storage tank 102, and the interfacial modifier compound 101 is liquid at room temperature and normal pressure. It is configured to vaporize. The heating means 103 is controlled by a CPU (not shown). That is, the CPU is electrically connected to each sensor such as a liquid quantity sensor of the interfacial modifier compound, a liquid temperature sensor, etc., and the liquid quantity and the liquid temperature of the interfacial modifier compound are within a specified range. The heating means is controlled to fit.
In the present invention, an example using a liquid interface modifying compound is given, but a gas or solid compound can also be used. When a gaseous interfacial modifier compound is used, the interfacial modifier compound storage tank section does not need to be provided with a heater, but instead may be provided with a flow regulating means such as a pressure regulating valve. . Further, when using a solid interfacial modifier compound, for example, the liquid transportation in which the solid compound is dissolved in a solvent or melted with heat and piped from the storage tank of this example to the vicinity of the flame of the burner. Interfacial reforming can also be performed by passing through a pipe and feeding directly into a burner.

"Transportation part"
As shown in FIG. 1, the transfer unit 105 has a “pipe” structure, and as shown in FIG. 1, the vaporized interface modifier compound supplied from the compressed air source 107 and delivered from the storage tank 102. The first submixer 108 for mixing the fuel gas, the mixed gas mixed by the first submixer 108, and the second gas for uniformly mixing the fuel gas delivered from the fuel gas storage tank 106. The main mixer 109 is provided.

"Injection part (burner)"
As shown in FIG. 1, the injection unit (burner) 104 burns the combustion gas sent through the transfer unit 105 and sprays the obtained flame 113 onto the surface to be reformed (not shown). The reformed surface is subjected to interfacial reforming, and the state of the flame 113 includes the flow rate of the vaporized interfacial modifier compound 101, the amount of combustion air sent from the compressed air source 107, and the fuel gas. Each flow rate of the amount of fuel gas delivered from the storage tank 106 is optimally adjusted by adjusting the opening degree of the flow rate adjustment valves 110, 111, 112 with flow meters provided in the respective gas flow paths. The The type of the burner is not particularly limited, and may be any of a premix burner, a diffusion burner, a partial premix burner, a spray burner, an evaporation burner, and the like. Further, the form of the burner is not particularly limited.

The interface modifier compound is not particularly limited as long as it is a compound containing a silane atom, a titanium atom or an aluminum atom and can burn in a flame of a general gas burner. In view of easy availability and handling, for example, a group consisting of an alkylsilane compound, an alkoxysilane compound, a siloxane compound, a silazane compound, an alkyl titanium compound, an alkoxy titanium compound, an alkyl aluminum compound, and an alkoxy aluminum compound. It is preferable that it is at least one compound selected from.
Preferred examples of the alkylsilane compound include methylsilane, dimethylsilane, trimethylsilane, tetramethylsilane, tetraethylsilane, dimethyldichlorosilane, dimethyldiphenylsilane, diethyldichlorosilane, diethyldiphenylsilane, methyltrichlorosilane, methyltriphenylsilane, and dimethyl. Substituents such as monosilane compounds that may have substituents such as diethylsilane, disilane compounds that may have substituents such as hexamethyldisilane, hexaethyldisilane, chloroheptamethyldisilane, and octamethyltrisilane A trisilane compound which may have
Preferred examples of the alkoxysilane compound include methoxysilane, dimethoxysilane, trimethoxysilane, tetramethoxysilane, ethoxysilane, diethoxysilane, triethoxysilane, tetraethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, and trimethylmethoxysilane. , Methyltriethoxysilane, dimethyldiethoxysilane, trimethylethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dichlorodimethoxysilane, dichlorodiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, trichloromethoxysilane, trichloroethoxysilane , Triphenylmethoxysilane, triphenylethoxysilane and the like alone or in combination of two or more .
Preferred examples of the siloxane compound include tetramethyldisiloxane, pentamethyldisiloxane, hexamethyldisiloxane, octamethyltrisiloxane, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexa Examples thereof include siloxane.
Preferable examples of the silazane compound include hexamethyldisilazane. Moreover, as a suitable example of an alkyl titanium compound, tetramethyl titanium, tetraethyl titanium, tetrapropyl titanium, etc. are mentioned. Preferable examples of the alkoxytitanium compound include titanium methoxide and titanium ethoxide. Preferable examples of the alkyl aluminum compound include trimethyl aluminum, triethyl aluminum, tripropyl aluminum and the like. Preferable examples of the alkoxyaluminum compound include aluminum methoxide, aluminum ethoxide and the like. These compounds may be used alone or in combination.
Among the above preferable examples, silane compounds, alkoxysilane compounds, siloxane compounds, and silazane compounds are more preferable because they are easy to handle, easily vaporized, and easily available.

  Next, using the interface reforming apparatus shown in FIG. 1 as described above, a polyolefin resin typified by a polypropylene resin, which is generally referred to as a hardly adhesive / hardly adhesive resin, is used as an example of a substrate to be coated. The concept will be described with reference to FIG. 2 in connection with a coating method in which a water-based polyurethane resin coating is securely adhered and adhered onto the substrate.

  First, as shown in the conceptual enlarged view of FIG. 2 (a), a difficult-to-adhere / hard-adhesive substrate 201 typified by polypropylene resin is prepared, and then using the interface reformer 100 shown in FIG. An interfacial modifier compound containing a silane atom, a titanium atom or an aluminum atom, each having a boiling point of 10 ° C. to 105 ° C., is introduced into the fuel gas together with combustion air in a gasified state. In addition, a flame of fuel gas obtained by burning the fuel gas so that the mixed molar ratio of air / hydrocarbon gas in the fuel gas becomes a value of 23 or more is a difficult adhesion / hard adhesion base material 201 typified by the polypropylene resin. The surface modification layer 202 made of silicon dioxide particles having a particle diameter of several nanometers to several tens of nanometers is formed on the surface interface of the difficult-to-adhere / hard-adhesive substrate 201.

The interfacial modified layer 202 made of silicon dioxide particles having a particle diameter of several nanometers to several tens of nanometers formed microscopically on the surface layer interface of the hardly adhesive / hardly adhesive substrate 201 typified by the polypropylene resin is microscopically shown. When magnifying, as conceptually illustrated in FIG. 3, a large number of hydroxyl groups (—OH) that are polar groups are present on the surface of the silicon dioxide particles (SiO ₂ ) 10 innumerable in the interface modification layer 202. The present inventor has already confirmed by reflection absorption spectroscopy (FT-IR).

Further, in the interfacial reforming of the base material 201, which is said to be a difficult-to-adhere / hard-adhesive resin typified by polypropylene resin, using the interfacial reformer 100, air / carbonization in the fuel gas is performed. The flame of the fuel gas, which is burned so that the mixing molar ratio of hydrogen gas becomes a value of 23 or more, is applied to the surface of the base material 201 which is said to be a hardly-adhesive contact / adhesive resin represented by the polypropylene resin. The reason for the uniform spraying treatment is that the amount of air is mixed in a relatively excessive amount from the normal combustion so that the air / hydrocarbon gas mixing molar ratio is 23 or more, so that the chemical reaction with the aqueous polyurethane resin paint in the next step is performed. It is thought that this is due to the formation of a large number of hydroxyl groups (—OH), which are the above-mentioned polar groups that can serve as a mechanical bond tentacle, around the silicon dioxide particles (SiO ₂ ) 10.

  Then, as shown in FIG. 2 (b), no prior primer treatment was performed on the polypropylene resin base material 201 as the hard-to-adhere / hard-adhesive base material on which the silicon dioxide particle layer 202 was formed by interfacial modification. Without coating, the aqueous polyurethane resin layer 203 is directly coated with a coating means or a coating means, and the water-based polyurethane resin layer 203 is hard to adhere to the substrate through the silicon dioxide particle layer 202 by forcibly heating and drying. -It will adhere | attach chemically firmly on the polypropylene resin 201 as a hard-to-adhere base material.

Therefore, the reason why a large number of hydroxyl groups (—OH), which are polar groups, are formed on the surface of SiO ₂ is that the molar ratio of air / hydrocarbon gas in the fuel gas in the interface reformer shown in FIG. Has been confirmed in the inventor's research, and the fact is described in the following patent document already filed by the inventor. Details are described.
Japanese Patent Application No. 2005-248364

  Next, the outline of the aqueous polyurethane resin according to the present invention will be described. The form of the water-based polyurethane resin that can be used in the present invention is not particularly limited, and is a two-component curable type comprising a main component having a hydroxyl group and a curing agent having an isocyanate group. Dispersed water-dispersible polyurethane resin, water-soluble paint in which resin component is dissolved in water in the form of resin acid salt, or emulsion in which water-insoluble resin, drying oil or varnish is dispersed in water The form of the resin does not matter, such as an emulsion type using a liquid as a vehicle.

In addition, as reference examples of the water-based polyurethane resin that can be used in the present invention, 1. A polyurethane water-soluble composition comprising a polyurethane resin containing at least one silanol group in the molecule and a strongly basic tertiary amine as a curing catalyst (see “Patent Document 3” below), or Reaction of a polyurethane prepolymer (A) obtained by reacting a disidroxy compound with a polyisocyanate compound having an isocyanate group average functionality of 3 to 6 and a compound (B) having two or more functional groups capable of reacting with an isocyanate group A water-based crosslinked polyurethane resin composition (see “Patent Document 4” below), and An aqueous polyurethane resin produced by reacting polyisocyanate, a polyfunctional compound having an active hydrogen atom (high molecular weight diol, chain extender, etc.) and hydrazone or a hydrazone derivative having an active hydrogen atom (the following “Patent Document 5”) See)), etc. Of course, various polyurethane resins called water-based or water-based other than the above reference examples can also be used.
JP-A-9-12864 JP-A-8-231666 JP 9-255751 A

  As described above, according to the present invention, by utilizing the “interface reformer” shown in FIG. 1 according to the present invention, various water-based polyurethane resins for various plastic base materials having poor adhesion and difficult adhesion. Coating and coating of coating materials can be easily performed without a primer, and printing and design imparting can be performed on various parts typified by various electronics products and various home appliances. In addition, in the application and application of various water-based polyurethane resin coating materials to various difficult-to-adhere and difficult-to-adhere plastic base materials, adhesion and adhesion between the base material and various water-based polyurethane resin coating materials are ensured. It is possible to reduce the number of man-hours for painting and coating various water-based polyurethane resin coatings on various plastic substrates, and energy saving can be achieved. It has become possible to greatly contribute to loss and productivity improvement.

  Hereinafter, with reference to the drawings, a coating / coating method of a water-based polyurethane resin coating material on a difficult-to-adhere / hard-adhesive substrate according to the present invention and a difficult-to-adhere / hard-adhesive group coated / coated by the same method A specific example of the material will be described.

[Example 1]
1. 2. Preparation of Base Material First, as shown in FIG. 2, a silicon rubber base material 201 was prepared, and the entire surface of the silicon rubber base material was washed with isopropyl alcohol (IPA) and degreased.

2. Next, the upper surface of the silicon rubber substrate 201 cleaned by the IPA is subjected to an interface reforming process using the interface reforming apparatus 100 shown in FIG. 1, and as shown in FIG. The interfacial modified layer 202 was obtained. The modified state of the interface reforming layer 202 was 73 dyn / cm or more in terms of the wetting index. Although the interface modification layer 202 is shown as a continuous layer of SiO _{2 in} the drawing, it is microscopically formed as a discontinuous layer of SiO ₂ .
Further, the interface modification work in this example was performed under the following conditions.

"Interface modification conditions"
・ Flame treatment fuel: propane gas ・ Modifier compound: Tetramethylsilane (boiling point: 27 ° C.)
-Discharge amount of modifier compound containing air: 1.3 (liter / min)
・ Air flow rate (Air): 84 (liter / min)
・ Gas flow rate (propane gas): 3.0 (liter / min)
・ Molar ratio of air / propane gas: 28
Processing time: 4 seconds / 100 cm ²
-Environmental conditions: 25 ° C, 60% Rh
・ Conversion agent compound content: Approximately 0.0002 mol% (when the total amount of modifier compounds including air is 100 mol%)

3. Application of water-based polyurethane resin And, on the interfacial modified layer 202 whose upper surface of the silicon rubber substrate 201 has been interfacially modified by the previous process, spray coating of a self-crosslinking polyurethane dispersion based on the following composition with a spray gun Then, a transparent coating layer having an average film thickness of about 20 μm as shown in FIG. 2B was obtained. Further, the silicon rubber base material 201 coated with the water-based polyurethane dispersion was put into a heating and drying furnace, and dried to form a film under the condition of 110 ° C. × 1 hr to obtain a transparent polyurethane resin layer 203.
"Formulation examples"
・ Self-crosslinking polyurethane dispersion: 97w%
(Mitsui Chemicals Polyurethane Co., Ltd .: Takerak (VS5000)
-Antifoaming agent: 2.9w%
(Bicchemi Japan Co., Ltd .: BYK-011)
・ Leveling agent: 0.1w%
(Bickemi Japan Co., Ltd .: BYK-333)

4). The adhesion / adhesion strength between the silicon rubber substrate 201 and the transparent cured polyurethane resin layer 203 through the interface reforming layer 202 shown in FIG. It was enough.
"Adhesion strength"
・ Cross cut, cellophane tape, peeling test: OK (100/100)
(JIS K5600-5-6)
・ 180 ° bending test: OK (no wrinkles)

[Example 2]
1. Preparation of Base Material First, as shown in FIG. 2A, a base material 201 made of an ethylene propylene diene three-dimensional copolymer (hereinafter abbreviated as “EPDM”) is prepared, and the entire surface of the EPDM base material is isopropyl alcohol. A degreasing treatment was performed after washing with (IPA).

2. Next, the upper surface of the EPDM substrate 201 cleaned by the IPA is subjected to an interface reforming process using the interface reforming apparatus 100 shown in FIG. 1, and as shown in FIG. An interface modified layer 202 was obtained. The modified state of the interface modified layer was 73 dyn / cm or more in terms of wetness index. Although the interface modification layer 202 is shown as a continuous layer of SiO _{2 in} the drawing, it is microscopically formed as a discontinuous layer of SiO ₂ . Further, the interface modification work in this example was performed under the following conditions.

"Interface modification conditions"
・ Flame treatment fuel: propane gas ・ Modifier compound: Hexamethyldisiloxane (boiling point: 101 ° C.)
-Discharge amount of modifier compound containing air: 1.3 (liter / min)
・ Air flow rate (Air): 84 (liter / min)
・ Gas flow rate (propane gas): 3.0 (liter / min)
・ Molar ratio of air / propane gas: 28
Processing time: 4 seconds / 100 cm ²
-Environmental conditions: 25 ° C, 60% Rh
-Modifier compound content: about 0.0002 mol% (when the total amount of modifier compounds including air is 100 mol%)

3. Application of water-based polyurethane resin And, on the interfacial modified layer 202 whose upper surface of the EPDM base material 201 has been interfacially modified in the previous process, spray coating with a two-component curable aqueous polyurethane resin based on the following composition using a spray gun Then, a transparent coating layer 203 having an average film thickness of about 20 μm as shown in FIG. 2B was obtained. Furthermore, the EPDM base material 201 coated with the two-component curable water-based polyurethane resin was put into a heating and drying furnace, and dried and formed under conditions of 110 ° C. × 1 hr to obtain a transparent polyurethane resin layer 203. .
"Formulation examples"
・ Main agent (acrylic polyol)
Vivirol: 93w%
(Sumitomo Bayern Urethane Co., Ltd., VPLS-2058)
Defoamer: 3w%
(Bicchemi Japan Co., Ltd .: BYK-011)
・ Curing agent (polyisocyanate)
Bamboo rack (VS5000): 7w%
(Mitsui Chemicals Polyurethane Co., Ltd.)

4). The adhesion / adhesion strength between the EPDM base material 201 and the transparent cured polyurethane resin layer 203 through the interface modification layer 202 shown in FIG. It was enough.
"Adhesion strength"
・ Cross cut, cellophane tape, peeling test: OK (100/100)
(JIS K5600-5-6)
・ 180 ° bending test: OK (no wrinkles)

[Example 3]
1. 2. Preparation of Base Material First, as shown in FIG. 2, a polyester-based thermoplastic elastomer base material 201 (manufactured by Mitsui Chemicals, Inc .: Primalloy) is prepared, and the entire surface of the polyester-based thermoplastic elastomer base material is isopropyl alcohol ( A degreasing treatment was performed after washing with IPA).

2. Interfacial Modification Treatment Next, the upper surface of the polyester-based thermoplastic elastomer substrate 201 cleaned by the IPA is subjected to an interfacial modification treatment using the interfacial reformer 100 shown in FIG. The interface reforming layer 202 as shown in FIG. The modified state of the interface modified layer was 73 dyn / cm or more in terms of wetness index. Although the interface modification layer 202 is shown as a continuous layer of SiO _{2 in} the drawing, it is microscopically formed as a discontinuous layer of SiO ₂ .
Further, the interface modification work in this example was performed under the following conditions.

"Interface modification conditions"
・ Flame treatment fuel: propane gas ・ Modifier compound: Tetramethylsilane (boiling point: 27 ° C.)
-Discharge amount of modifier compound containing air: 1.3 (liter / min)
・ Air flow rate (Air): 84 (liter / min)
・ Gas flow rate (propane gas): 3.0 (liter / min)
・ Molar ratio of air / propane gas: 28
Processing time: 5 seconds / 100 cm ²
-Environmental conditions: 25 ° C, 60% Rh
-Modifier compound content: about 0.0002 mol% (when the total amount of modifier compounds including air is 100 mol%)

3. Application of water-based polyurethane resin Then, spraying of the heat-drying water-based polyurethane resin based on the following composition is sprayed on the interfacial reforming layer 202 whose upper surface of the polyester-based thermoplastic elastomer base material 201 is interfacially modified in the previous process. Spray coating was performed with a gun to obtain a transparent coating layer 203 having an average film thickness of about 20 μ as shown in FIG. Further, the polyester thermoplastic elastomer base material 201 coated with the heat-drying water-based polyurethane resin is put into a heating and drying furnace, and dried and formed under conditions of 110 ° C. × 1 hr. Got.
"Formulation examples"
・ Main agent (acrylic polyol)
Vivirol: 93w%
(Sumitomo Bayern Urethane Co., Ltd., VPLS-2058)
Defoamer: 3w%
(Bicchemi Japan Co., Ltd .: BYK-011)
・ Curing agent (polyisocyanate)
Bamboo rack (VS5000): 7w%
(Mitsui Chemicals Polyurethane Co., Ltd.)

4). The adhesion / adhesion strength between the EPDM base material 201 and the transparent cured polyurethane resin layer 203 through the interface modification layer 202 shown in FIG. It was enough.
"Adhesion strength"
・ Cross cut, cellophane tape, peeling test: OK (100/100)
(JIS K5600-5-6)
・ 180 ° bending test: OK (no wrinkles)

  As described above in detail, according to the present invention, it is difficult to adhere to a resin such as polyethylene (PE) resin and polypropylene (PP) resin, which are generally referred to as difficult adhesion / hard adhesion resin. Hardly adhesive resin base material, especially polyester elastomer, olefin thermoplastic elastomer, styrene thermoplastic elastomer, etc. or other elastomers such as natural rubber, silicone rubber, etc.・ It is possible to reliably adhere and adhere water-based polyurethane resin coating materials that are said to be difficult to adhere and adhere to difficult-to-adhesive resin substrates without applying pre-treated primers that have been generally used in the past. It becomes possible in various industrial fields such as various parts related to home appliances and electronics, various parts related to automobiles, etc. It is possible to greatly contribute to creating that various parts.

Outline of interface reformer Conceptual drawing of water-based polyurethane resin coating on difficult-to-adhere substrates Magnified schematic diagram for explaining the surface state of silicon dioxide particles (SiO ₂ )

Explanation of symbols

DESCRIPTION OF SYMBOLS 100: Interface modifier 101: Interface modifier compound 102: Storage tank part 103 for interface modifier compounds 103: Heating means 104: Injection part (burner)
105: Transfer unit 106: Fuel gas storage tank 107: Compressed air source 108: Submixer 109: Main mixer 110: Flow rate adjusting valve with flow meter 111: Flow rate adjusting valve with flow meter 112: Flow rate adjusting valve with flow meter 113: Flame 201: Difficult adhesion / hard adhesion base material 202: Interface modification layer 203: Polyurethane resin layer 10: Silicon dioxide particles (SiO ₂ )

Claims (4)

    A modifier compound containing a silane atom, a titanium atom or an aluminum atom, each having a boiling point of 10 ° C. to 105 ° C. is introduced into the fuel gas together with combustion air in a gasified state, A flame of fuel gas, which is burned so that the mixed molar ratio of air / hydrocarbon gas in the fuel gas becomes a value of 23 or more, is sprayed on the surface of the hard-to-adhere / hard-adhesive plastic substrate, After subjecting the surface of the base material to surface activation treatment so that the wetness index is 73 dyn / cm or more, an aqueous polyurethane resin coating material is directly applied to the interface subjected to the surface activation treatment without passing through a primer treatment step. A method of painting and coating a water-based polyurethane resin coating material on a difficult-to-adhere and difficult-to-adhesive substrate, characterized in that the coating is performed by means of painting and coating.   A hard-to-adhere / hard-adhesive plastic base material obtained by painting and coating an aqueous polyurethane resin coating material by the method according to claim 1.   The hard-to-adhere / hard-adhesive plastic base material according to claim 2 is a polyethylene resin, polypropylene resin, polyamide resin, polyethylene terephthalate resin, polycarbonate resin, polyphenylene ether resin, polybutylene terephthalate resin, polyphenylene sulfide resin, polyamide A hard-to-adhesive / hard-adhesive plastic base material obtained by coating and coating an aqueous polyurethane resin coating material, which is one thermoplastic resin selected from an imide resin and a polytetrafluoroethylene resin.   The hard-to-adhere / hard-adhesive plastic base material according to claim 2 is typified by a thermoplastic elastomer such as polyester-based thermoplastic elastomer, olefin-based thermoplastic elastomer, styrene-based thermoplastic elastomer, natural rubber, or silicon rubber. A hard-to-adhere / hard-adhesive plastic substrate obtained by coating and coating a water-based polyurethane resin coating material, characterized in that it is one thermoplastic elastomer selected from the group of other thermoplastic elastomers .

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