JP2003340362A - Method for reforming surface of material and reformed molded body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for treating a surface of a material instantaneously curing a UV ray curable coating used without generating a problem such as deformation, decomposition, discoloration or the like caused by excessive heating or the like. <P>SOLUTION: A mixture layer of an acrylate-based multifunctional compound having two or more of polymerizable functional groups polymerizable by the UV ray and a photoinitiator is formed on a surface of the object material and the mixture is cured by flash irradiation with UV ray using a UV ray emission device having a flash type discharge mechanism. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for modifying the surface of a base material of a molded article for housing equipment such as bathroom equipment such as bathtubs and bathroom wash pans, kitchen equipment such as sinks, and the like. The present invention relates to a modified molded body.

[0002]

2. Description of the Related Art In recent years, the surface of a base material of a molded article has been modified by imparting functionality such as hard coat property, hydrophilicity or antifouling property to the surface of the base material. The method of heating and curing the above-mentioned thermosetting coating is changing to a method of irradiating the ultraviolet curing coating applied to the surface of the base material with ultraviolet rays or the like to cure. For example, JP-A-8-12686
No. 1 gazette discloses that an existing coating film and stains on a portion to be repaired (such as a restaurant counter) are removed, and an ultraviolet curable paint is applied to the portion, which can be turned on by a household power source.
There is disclosed a method of irradiating ultraviolet rays to cure a paint by using an ultraviolet irradiating device equipped with a high-pressure mercury lamp or a metal halide lamp of 0 to 2000 W to easily and easily repair an interior material in a store.

[0003]

However, in these conventional methods using ultraviolet irradiation, the ultraviolet irradiation required for curing the paint requires several seconds or several minutes. The object of the present invention is to
A method for modifying the surface of a base material (of a molded product) based on the principle of UV curing, which allows the UV curable coating used to be used instantaneously without causing problems such as deformation, deterioration or discoloration due to excessive heating. The present invention provides a method for treating a surface of a base material that is cured to the above, and a molded article whose surface is modified by the method.

[0004]

In order to solve the above problems, the present invention has the following constitution. That is, the present invention provides a layer of a mixture (ultraviolet curable composition) of an acrylate polyfunctional compound having two or more polymerizable functional groups capable of being polymerized by ultraviolet rays and a photopolymerization initiator on the surface of a target substrate. A method for modifying the surface of a base material is characterized in that the mixture is formed, and the mixture is cured by irradiating the mixture with an ultraviolet ray emitting device having a flash discharge mechanism to irradiate it with ultraviolet rays.
The base material is preferably one that can be directly coated with the ultraviolet-curable composition without requiring any pretreatment (that is, pretreatment). However, the surface of the base material may be pretreated by sanding, frame treatment or the like to improve the adhesion.

The mixture containing the acrylate polyfunctional compound and the photopolymerization initiator preferably contains colloidal silica.

In the ultraviolet light emitting device of the flash type discharge mechanism, it is preferable to use, as a light source lamp, a highly durable lamp such as a xenon flash lamp that can withstand repeated light emission.

The present invention is also a molded article whose substrate surface is modified by the above method, and the modified surface has the following 5 performances when evaluated by the test method described below. The present invention also relates to a molded body satisfying one or more of the above, and particularly preferable ones satisfy all five items. -Glossiness: 90 or more-Weather resistance: No change-Hard code property: Good-Contact angle (against water): 60 ° or less-Stain resistance (hemanicure) or stain resistance (fatty acid calcium): Good

[0008] The modified molded product can be used in a wide range of equipment such as bathroom equipment of household equipment, kitchen equipment, sanitary equipment, indoor equipment or appliances such as furniture, or outdoor equipment or appliances such as gate posts, lamps, and outer walls. In particular, it is suitable for bathroom use or kitchen use.

[0009]

[Function] A mixture containing a "acrylate polyfunctional compound having two or more polymerizable functional groups capable of being polymerized by ultraviolet rays" and a photopolymerization initiator applied in a thin layer on the surface of the substrate (ultraviolet curable composition) Is instantaneously cured (photopolymerization reaction) by flashing ultraviolet energy from the flash type ultraviolet light emitting device. The cured film formed on the surface of the base material imparts high glossiness and also high weather resistance. When the ultraviolet curable composition containing colloidal silica is used, it further imparts a hard coat property, hydrophilicity and antifouling property to the surface of the substrate.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail. Various organic or inorganic base materials (materials) can be used as the base material of the target object to be surface-treated. As the organic substrate, polypropylene, polyethylene, polycarbonate, polyimide, polyethylene terephthalate, nylon, acrylic, polyvinyl chloride, polystyrene, unsaturated polyester, epoxy, polyurethane,
There are resins such as phenol, dicyclopentadiene and ABS. Glass fibers (reinforcing material) and other fillers may be contained in these resins. The bathroom wall material may include a joint material (silicone caulking or polyvinyl chloride). Natural organic materials such as wood and composite materials containing wood may be used. Examples of the inorganic substrate include stainless steel, iron, aluminum plates, zinc steel plates, parts made of these metals, ceramic members such as pottery, enamel, and glass, as well as mortar and concrete as outer wall materials.

In order to improve the coating property (adhesion) of the ultraviolet curable composition on the substrate, the substrate surface can be pretreated. Usually, after degreasing the surface of the substrate, one or more of them are selected from sanding, flame treatment, corona discharge treatment, UV irradiation treatment, primer treatment (using a silane coupling agent), and the like. These pretreatments are
It is appropriately selected according to the type of substrate and the characteristics of the ultraviolet curable composition.

The ultraviolet-curable composition used is a mixture containing at least a polyfunctional acrylate compound having two or more polymerizable functional groups capable of being polymerized by ultraviolet rays and a catalytic amount of a photopolymerization initiator. The acrylate-based polyfunctional compound may have an acryloyl group, a methacryloyl group, or other functional group or bond. Other functional groups and bonds include a hydroxyl group, a carboxyl group, a halogen atom, a urethane bond, an ether bond, an ester bond, an amide bond and the like. As the photopolymerization initiator, there are acetophenones, benzophenones, benzyls, and the like, which are selected according to the wavelength of ultraviolet rays to be irradiated. In addition to the photopolymerization initiator, a light stabilizer or an ultraviolet absorber may be contained.

The UV-curable composition preferably contains 5 to 300 parts by weight of colloidal silica based on 100 parts by weight of the acrylate-based polyfunctional compound (monomer). This is to improve the hard coat property, hydrophilicity, antifouling property, and other functional properties of the coating film. The solid content of the UV-curable composition when a solvent is not used is usually about 40% by weight. In order to improve the adhesion of the ultraviolet curable composition to the substrate, 0.1 to 3.0 parts by weight of the silane coupling agent can be added to 100 parts by weight of the solid content.

If necessary (for workability of the coating film and adjustment of the coating film thickness), it may be diluted with a solvent. Examples of the solvent include ethanol, isopropyl alcohol, butanol, toluene, xylene, methyl cellosolve, ethyl cellosolve, ethyl acetate, butyl acetate and methyl ethyl ketone (MEK). Usually, the solid content concentration is 5 to
The concentration is adjusted within the range of 40% by weight.

The UV-curable composition whose solid content concentration is appropriately adjusted can be used for brush coating, spray coating, spin coating,
It is applied to the substrate by a coating method such as flow coating or roll coating. After coating, the solvent is sufficiently volatilized, and ultraviolet rays are flashed by using an ultraviolet ray generator of a flash type discharge mechanism. The thickness of the coating film after curing is preferably about 1 to 50 μm.

The ultraviolet ray generation device of the flash type discharge mechanism is a device having a function of allowing the light source to flash light repeatedly. The lamp used is preferably one with excellent durability, such as a xenon flash lamp,
The flash irradiation time at this time is on the order of μ seconds to milliseconds, and is a time not exceeding 1 second at the longest.

The flash time is set so that the amount of irradiation energy required to cure the ultraviolet curable composition is set,
Alternatively, the irradiation is repeatedly performed so that the integrated value has a necessary irradiation energy amount. Since ultraviolet light has optical attenuation in the distance from the light source to the substrate, the irradiation energy is measured with an ultraviolet illuminometer or the like before irradiation.

Since the flash irradiation time is an extremely short time on the order of μ seconds to m seconds as described above, the temperature of the base material hardly rises, and deformation, discoloration or deterioration due to temperature rise is not caused. Even if it happens, the extent of it is insignificant, and it does not hinder practical use. In the case of a base material made of a thermoplastic resin having a low softening point, the flash type processing method according to the present invention is particularly effective.

Further, even if the target molded article has a complicated shape, since the irradiation time is very short, it is easy to perform the ultraviolet irradiation treatment while holding the molded article manually (the load is small).
It is also easy to perform surface treatment work on site.

The substrate surface obtained by the flash treatment method of the present invention is imparted with high gloss and high weather resistance due to the cured product (polyacrylate). Moreover, when a mixture containing colloidal silica is used, the surface of the base material is imparted with hard coat property, hydrophilicity and antifouling property due to the silica.

[0021] The reforming method and the modified molded body of the present invention can be used for bathroom equipment (bathtub, washing pan,
Wall panels, ceilings, counters, joints, faucets, mirrors, washbasins, chairs, etc., kitchen equipment (kitchen counters, kitchen panels, stoves, hoods, sinks, cabinets, etc.), sanitary (washbasins, bowls, In addition to interior items such as mirrors, storage shelves, toiletries, toilet bowls, toilet seats, etc., furniture (trunks, tables, floors, etc.), exterior items (parts) such as gate posts, lamps, outer walls, panel tanks, septic tanks, solar water heaters, etc. Applicable to

The reforming method of the present invention may be incorporated during the manufacturing process of a molded body, or may be used when repairing an existing product.

[0023]

[Examples] Examples and comparative examples will be described in more detail below. The physical properties were measured and evaluated by the following methods.

<Glossiness> Gloss meter: made by Nippon Denshoku, measured at 60 ° reflectance <Weather resistance> Rainfall 1 using a sunshine weather meter
2 minutes, 48 minutes drying, 100 ° C under 63 ° C temperature cycle
Test for 0 hours and evaluate the change in appearance. <Hard coat property> Using steel wool # 00, 10
It was rubbed 100 times with a pressure of KPa and evaluated by the number of scratches after rubbing. ⊚ (good): 0 ◯ (somewhat good): 1 to 2 Δ (somewhat bad): 3 to 10 x (bad): 10 or more <Hydrophilicity> The contact angle of water was measured. "GA-X150" manufactured by Kyowa Interface Science Co., Ltd. was used. <Anti-fouling property (hair manicure)> Hair nail polish is dropped, and after standing for 24 hours, it is washed with water to visually determine how much stain remains. ⊚ (Good): No residue at all ○ (Somewhat good): Slightly remains but almost unknown Δ (Somewhat bad): Slightly remains X (defective): clearly understood. <Anti-fouling property (using fatty acid calcium)> When sodium laurate is dissolved in hot water and calcium chloride is added, fatty acid calcium similar to soap residue is generated as scum. The sample is taken in and out of the floating cup of the scum 10 times, and the scum is forced to adhere to the surface. After the scum-attached sample was washed off with a shower, the state of gloss and stain adhesion was visually evaluated. ⊚ (Good): Almost all stains removed ○ (Slightly good): Slightly remained but almost removed Δ (Slightly bad): Slightly remained X (Poor): Remains clearly.

Example 1 A surface-untreated bathroom counter (made of ABS resin) 0.5 m ² was used as a molded article (base material) whose surface was to be modified. Regarding the surface of this base material, the result of separately testing is
As follows. Gloss: 75 Weather resistance: slightly yellowing, embrittlement Hard code property: × Contact angle: 81 ° Contamination resistance (hemanicure): × Contamination resistance (fatty acid calcium): ×

An ultraviolet curable composition containing an acrylate polyfunctional compound having two or more polymerizable functional groups capable of being polymerized by ultraviolet rays, a photopolymerization initiator, and colloidal silica (HB-320NDS manufactured by Asahi Glass Co., Ltd.) Is diluted with an equal weight of ethyl cellosolve (solvent), and spray-coated on the molded product (base material) to a film thickness of about 5 μm.
After heating at ℃ for 1 minute to volatilize the solvent, use a flash type ultraviolet light emitting device (Xenon flash lamp made by USHIO INC., Irradiation range is about 0.04 m ² ) to generate energy 3
The light was emitted and irradiated at 00 J from a distance of 30 mm. The light emission / irradiation time was set to 1 msec, and the entire surface of the target molded article was irradiated 12 times. The total irradiation time for the entire surface is about 8
It was seconds. No temperature rise, discoloration or deformation of the substrate was observed. The characteristics of the substrate surface after the treatment are as follows. Gloss: 93 Weather resistance: No change Hard code: ◎ Contact angle: 60 ° Contamination resistance (hemanicure): ○ Contamination resistance (fatty acid calcium): ○

Comparative Example 1 A comparative test was conducted using the same molded article (base material) used in Example 1. A typical UV curable composition (Aronix 3701 manufactured by Toagosei Co., Ltd.) is applied by spin coating to a film thickness of about 5 μm, and the UV irradiation device (irradiation range is 0.04 m ² ) of a high pressure mercury lamp is irradiated from a distance of 20 mm. Then
Cured. When the irradiation time was 30 seconds, the characteristics of the film (cured product) showed the best values. However, after 30 seconds, heating by the high-pressure mercury lamp proceeded, the temperature of the irradiated part partially rose, and the discoloration like burnt was observed, and crater-like deformation was also observed. It took about 7 minutes to irradiate the entire surface of the counter of 0.5 m ² divided into 12 times, and the total working time was about 10 minutes. The characteristics of the substrate surface after the treatment are as follows. Glossiness: 93 Weather resistance: No change Hard code: ○ Contact angle: 85 ° Contamination resistance (hemanicure): ○ Contamination resistance (fatty acid calcium): △

Example 2 A surface-untreated acrylic vacuum forming bath 3.7 m ² was used as a molded product (base material) whose surface was to be modified. The results of separately testing this substrate surface are as follows. Glossiness: 88 Weather resistance: No change Hard code property: × Contact angle: 85 ° Contamination resistance (hemanicure): △ Contamination resistance (fatty acid calcium): ×

An ultraviolet-curable composition (HB-320NDS manufactured by Asahi Glass Co., Ltd.) containing an acrylate-based polyfunctional compound having two or more polymerizable functional groups capable of being polymerized by ultraviolet rays, a photopolymerization initiator, and colloidal silica. Is diluted with an equal weight of ethyl cellosolve (solvent), a film thickness of about 8 μm is applied to the molded product (base material) by brushing, and the solvent is volatilized by heating with a heat gun, followed by a flash method. Ultraviolet light emitting device (Usio Denki xenon flash lamp,
The irradiation range is about 0.04 m ² ) and the energy is 520
In J, light was emitted and irradiated from a distance of 50 mm. Luminous time is 1
The entire surface of the substrate was irradiated with msec for several times. It took about 60 seconds until the irradiation of the entire surface was completed. No temperature rise, discoloration or deformation of the substrate was observed. The characteristics of the surface of the base material after the treatment after being immersed in 40 ° C. hot water for 24 hours are as follows. Glossiness: 93 Weather resistance: No change Hard code: ◎ Contact angle: 40 ° Contamination resistance (hemanicure): ○ Contamination resistance (fatty acid calcium): ○ The molded product is immersed in water like a bath. For a long time, the surface hydrophilization gradually progresses with time,
The contact angle becomes smaller. In addition, the antifouling property (fatty acid calcium) performance is also improved accordingly. This means a self-cleaning action due to hydrophilicity.

Comparative Example 2 A comparative test was conducted using the same molded product (base material) used in Example 2. An ultraviolet curable composition (HB-320NDS manufactured by Asahi Glass Co., Ltd.) containing an acrylate-based polyfunctional compound having two or more polymerizable functional groups capable of being polymerized by ultraviolet rays, a photopolymerization initiator, and colloidal silica was used. After diluting with a weight of ethyl cellosolve (solvent), apply a brush coating to the above-mentioned molded product (base material) to a film thickness of about 5 μm, and heat with a heat gun to volatilize the solvent, and then use ultraviolet light from a high-pressure mercury lamp. Irradiation was carried out from a distance of 20 mm using an irradiation device (irradiation range was 0.04 m ² ) to cure. When the irradiation time was 30 seconds, the characteristics of the film (cured product) showed favorable values. But 3
When it exceeded 0 seconds, heating by the high-pressure mercury lamp proceeded, and the temperature of the irradiation site partially rose too much, and the shape of the bathtub was deformed. Further, the temperature of the lamp was too high, and it was necessary to cool it when the curing was completed about 1/3. 3.5
The irradiation time is about 45 minutes to irradiate the entire surface of the m ² bathtub,
The total working time including cooling was about 60 minutes. After the treatment, the characteristics of the surface of the base material after being immersed in 40 ° C hot water for 24 hours are as follows. Gloss: 93 Weather resistance: No change Hard code: ◎ Contact angle: 40 ° Contamination resistance (hemanicure): ○ Contamination resistance (fatty acid calcium): ○

[0031]

According to the method for modifying the surface of a substrate of the present invention,
Ultraviolet curable composition applied on the surface of a base material (of a molded product) without causing deformation and cracks due to shrinkage during curing, and without causing problems such as deformation, deterioration and discoloration due to overheating. Can be instantaneously cured to form a cured film on the surface of the base material in a short time. It is possible to modify the surface of a substrate having a large surface area such as a bathroom bathtub, a bathroom wash pan, a kitchen sink, furniture, gate posts, lamps, and outer walls with less energy loss and in a short working time. The cured film formed on the surface of the base material imparts high glossiness to the surface of the base material and also high weather resistance. Further, when the ultraviolet curable composition containing colloidal silica is used, the hard coat property, hydrophilicity and antifouling property are further imparted to the surface of the base material. The modified molded product obtained in the present invention has high glossiness and high weather resistance on the surface of the base material, and in addition to this, hard coat property, hydrophilicity and antifouling property. It can be applied to a wide range of equipment such as bathroom equipment, kitchen equipment, sanitary equipment, indoor equipment or appliances such as furniture, outdoor equipment or appliances such as gate posts, lamps, outer walls, etc., and is particularly suitable for molded products for bathroom applications or kitchen applications. .

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // C08L 101: 00 C08L 101: 00 (72) Inventor Yoshio Suzuki Shimodate-shi, Ibaraki 1250 Shimoeren F-term in Hitachi Housetec Yuki Plant (reference) 4D075 BB42Z BB46Z BB54Z CA02 CA13 CA32 CA34 CA37 CB04 DA06 DB02 DB04 DB05 DB07 DB12 DB13 DB14 DB21 DB35 DB36 DB37 DB38 DB43 DB46 DB47 DB48 DB49 DB50 DB53 DB61 DC02 DC05 DC38 EA07 EA07 EB22 EB24 EC03 4F073 AA01 AA02 AA07 BA06 BA13 BA19 BA22 BA23 BA26 BA28 BA29 BB01 CA45 FA01

Claims (4)

[Claims] 1. A layer of a mixture of an acrylate polyfunctional compound having two or more polymerizable functional groups capable of being polymerized by ultraviolet rays and a photopolymerization initiator is formed on the surface of a substrate, and a layer of a flash type discharge mechanism is formed on the layer. A method for modifying the surface of a substrate, which comprises irradiating ultraviolet rays with a flash using an ultraviolet light emitting device to cure the mixture. 2. The method according to claim 1, wherein the mixture further contains colloidal silica. 3. A molded article having a substrate surface modified by the method according to claim 1 or 2. 4. The modified molded product according to claim 3, which is used for bathrooms or kitchens.