JP2003314959A - Drying device and method of resin coating material applied on plastic base material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device and a method of drying a resin coating material applied to a plastic base material capable of forming a hardened film in a short time without thermally deforming the plastic base material when the thermosetting resin coating material is applied onto the plastic base material, and then dried and hardened. <P>SOLUTION: An endless conveying means 34 for conveying the plastic base material 43 coated with the resin coating material, in a circulated heating atmosphere, and one or more near infrared ray heaters 38 including a near infrared ray lamp mounted at an upper part of the endless conveying means 34 are installed in a thermosetting furnace 32, and a space 33 in the thermosetting furnace 32 is partitioned into one or more drying zones of which temperatures are independently controlled. Whereby the thermosetting resin coating material is applied to the thermally deformable plastic base material 43, and then the resin coating material can be hardened by applying the near infrared ray to the plastic base material 43 coated with the resin coating material in the circulating heating atmosphere. <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 technique and apparatus for drying a resin coating material applied to a plastic substrate.

[0002]

2. Description of the Related Art A molded plastic substrate such as a plastic lens is required to have a thermosetting property because it is necessary to impart scratch resistance, impact resistance, weather resistance, electrical conductivity and antifogging property to its surface. A technique has been adopted in which a resin coating material is applied and then the resin coating material is heated and dried in a thermosetting oven to be cured.

In this case, the polyurethane resin paint in the above resin paint is used in a temperature atmosphere of 80 to 90.degree.
For 0 to 40 minutes, the thermosetting acrylic resin paint is 120 to
It is said that heat-drying the silicone-based resin coating material for 20 to 30 minutes in a temperature atmosphere of 150 ° C. and for 60 to 180 minutes in a temperature atmosphere of 120 to 130 ° C. is an essential condition for thermosetting. ing.

Further, in recent years, as described above for a member made of a different material composed of a plastic base material molded to meet the demand for high-mix low-volume production and other materials such as metals and carbon fibers. It is also practiced to apply a thermosetting resin paint.

[0005]

However, when the resin coating material applied to the above-mentioned members composed of different materials is dried, cracks and the like are generated due to the difference in linear expansion coefficient due to the difference in the materials. There was an inconvenience that it occurred and damaged the commercial value.

Further, in the case of a plastic substrate having a low heat distortion temperature of, for example, 100 ° C. or lower, when the curing condition of the thermosetting resin coating material applied to the plastic base material is higher than the above deformation temperature, the heat deformation is caused. In addition to the problem that drying has to be performed for a long time at a temperature lower than the temperature, there is a problem that a desired resin coating cannot be used because the plastic substrate itself is thermally deformed.

Particularly, those having a curing condition such as a high curing temperature such as a silicone-based resin coating and a long curing time, for example, have a heat distortion temperature of 100 ° C. or less, such as a plastic lens or an acrylic resin. There is a disadvantage that it cannot be applied to plastic substrates such as products.

Further, in the conventional ordinary heat circulation type curing furnace, since the curing progresses only from the surface side of the resin coating, it takes a long time to cure and coating defects such as pinholes occur. There was a problem that was easy to do.

In view of the above problems of the conventional method, the present invention applies a thermosetting resin coating material to a plastic substrate, and when the resin coating material is dried and cured, thermal deformation is caused on the plastic substrate side. It is an object of the present invention to provide an apparatus and a method for drying a resin coating applied to a plastic base material, which can be cured at a low temperature for a short time only on the resin coating side without being generated.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and a first invention device among them is an opening / closing door for inserting and removing a plastic base material coated with a resin paint. At least a blower arranged to freely supply and exhaust air to and from the drying chamber via an air supply duct and an exhaust duct, and the drying chamber is arranged in order from the upstream of the air supply duct. The blowing of the hot air generated through the heater and the filter, and the near-infrared radiation from the near-infrared heater including the near-infrared lamp installed in the drying chamber are freely formed, and from the drying chamber The air is freely exhausted from the bottom side through the exhaust duct to a part of the outside, and with the newly taken air, the rest is returned to the air supply duct side. It is characterized in configuration to the.

A second apparatus invention includes an endless conveying means for conveying a plastic substrate coated with a resin paint in a circulating heating atmosphere, and a near infrared lamp installed above the endless conveying means. One or more near-infrared heaters are provided in the heat curing furnace, and the space in the heat curing furnace is partitioned by one or more drying zones whose temperature is controlled separately.

Further, in the third invention device, the sheet-shaped plastic base material before the resin coating is applied is wound in a roll shape on the starting end side roll portion, and the drawing end pulled out from the starting end side roll portion side. A resin paint tank for applying a resin paint to one side, a thermosetting furnace for passing the drawer piece that has passed through the resin paint tank, and an end of the drawn-out piece after passing in a roll shape at its end side. And one or more near-infrared heaters including a near-infrared lamp, and
The space in the heat curing furnace provided with a circulating heating atmosphere,
It is characterized in that it is partitioned by at least one drying zone whose temperature is controlled separately.

On the other hand, the method of the present invention comprises a step of applying a thermosetting resin coating material to a plastic base material which undergoes thermal deformation, and a near infrared ray in a circulating heating atmosphere for the plastic base material coated with the resin coating material. And a step of irradiating the resin coating to cure the resin coating material. In this case, the resin coating material is applied in any one coating layer of polyurethane resin coating material, acrylic resin coating material and silicone resin coating material, or in a combination of two or more so as to form two or more coating layers. be able to.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the first of the devices of the present invention.
2 is a left side view of the invention device of FIG.

According to these drawings, the drying device 11 is provided with an opening / closing door 14 which is openably and closably attached via a hinge 15 for moving in and out a plastic base material coated with a resin paint.
A drying chamber 13, an air supply duct 17 and an exhaust duct 2
And a blower 16 which is freely arranged to supply and exhaust air to and from the drying chamber 13 through the frame 12. The "plastic base material" in the present specification includes, for example, CR-39 manufactured by PPG and NK manufactured by NOF Corporation.
55, Mitsui Chemicals' MR-6, MR-7, MR-8, M
R-90 and refractive index 1.74 lens, Mitsubishi Gas Chemicals 1.71 lens, Kureha Chemicals K-136, plastic resin such as polycarbonate resin (Sumitomo Dow,
Bayer, Teijin Kasei), plastic plates such as acrylic resin and polycarbonate resin and molded products (Sumitomo Dow, Bayer, Teijin Kasei), polyester resin, polycarbonate resin, acrylic resin and polyolefin resin plastic film The molded products (Sumitomo Dow, Bayer, Teijin Kasei) are included.

In this case, the inside of the drying chamber 13 is generated through a heater 18 and a filter 19 such as a HEPA filter which are sequentially arranged from the upstream side of an air supply duct 17 whose flow rate is freely adjustable via a damper 27. The heated hot air is blown from the ceiling side or side surface side, and the near infrared rays are directed downward or sideward from a pair of near infrared heaters 20, 20 including near infrared lamps installed on the ceiling side or side surface side. And are formed freely.

Further, the air is drawn from the drying chamber 13 through the exhaust box 22 from the bottom portion 21 side and the exhaust box 24 on the exhaust duct 23 side whose flow rate can be freely adjusted via a damper 26. Exhausting part of it to the outside,
The outside air newly taken in through the suction filter 25 and the rest of the outside air can be freely returned to the air supply duct 17 side.

FIG. 3 is an explanatory view showing an example of a second invention device of the invention devices, in which (a) is an overall configuration diagram and (b) is related to (a). It is a graph which shows the distribution state of temperature.

As shown in the figure, the entire drying device 31 includes an endless transfer means 34 for transferring a plastic base material 43 coated with a resin coating material in a heating atmosphere in which hot air blown down from the ceiling side is circulated. One or more near-infrared heaters 3 including near-infrared lamps installed above the endless conveying means 34
And 8 in a thermosetting oven 32.

In this case, the thermosetting oven 32 is provided with a start end side shutter 39 and an end side shutter 40, and an endless conveying means 34 including a coin bear belt 35 and belt wheels 36 and 37 is provided in the space 33. Has been formed.

Further, a large number of plastic substrates 43 such as plastic lenses are placed in a rack 42, and the resin coating is applied to the exposed surface of the rack 42 by submerging the rack 42 together in a resin coating tank 41. Has become.

The plastic base material 43 thus coated with the resin coating material is placed on the conveyor belt 35 together with the rack 42 and conveyed in the space 33 for a predetermined time.

Moreover, the space 33 in the heat curing furnace 32 is
As shown in FIG. 3 (b), a first zone for preliminary drying in which the temperature is raised from about 40 ° C., a second zone for main drying having a peak temperature of 80 to 90 ° C., and a main drying After that, the temperature is lowered to about 40 ° C. and is divided into a third zone for finish drying.

FIG. 4 is an explanatory view showing an example of a third invention device of the invention devices, of which (a) is an overall configuration diagram and (b) is a relation with (a). It is a graph which shows the distribution state of temperature.

As shown in the figure, the drying device 51 as a whole has a starting end side roll portion 52 in which a sheet-shaped plastic substrate before being coated with a resin coating material is wound in a roll shape, and the starting end side roll portion 52. Resin paint tank 54 for applying a resin paint to the pull-out piece portion 60 drawn out from the side through the guide roller 53
And the pull-out piece 60 passing through the resin paint tank 54 through the inlet 6
1 is introduced and guided by the guide roller 57 to the outlet 6
It is composed of a thermosetting oven 55 that allows passage from the outlet 2 to freely pass through, and an end-side roll portion 58 in which a pull-out piece portion 60 led out from the outlet 62 is wound into a roll shape on the end side thereof. .

In this case, on the ceiling side in the heat curing furnace 55,
At least one near infrared heater 56 including a near infrared lamp is installed. Further, in the space 55a of the thermosetting furnace 55, a heating atmosphere in which hot air blown down from the ceiling side is circulated is formed.

Moreover, the space 55a in the heat curing furnace 55 is
As shown in FIG. 4 (b), the first zone for preliminary drying in which the temperature is raised from about 40 ° C., and 80 to 90 ° C.
It is divided into a second zone for main drying having a peak temperature of 3 ° C and a third zone for finishing drying by finishing the main drying and lowering the temperature to about 40 ° C.

Next, regarding the method of the present invention, the second method shown in FIG.
The invention will be described with reference to the apparatus of the invention of FIG.
1 and the thermosetting resin paint is applied to the rack 4 and the plastic base material 43 to which the resin paint is applied.
And a step of carrying the resin in the thermosetting furnace 32 by placing it on the conveyor belt 35 together with 2 and irradiating near infrared rays from the near infrared heater 38 in the circulating heating atmosphere in the space 33 to cure the resin fat paint. At least through.

In this case, the resin coating material can be applied so as to form one of the coating layers of polyurethane resin coating material, acrylic resin coating material and silicone resin coating material. It is also possible to apply the above-mentioned coating layer.

Table 1 shows the curing conditions and evaluation results for Comparative Example 1 and Example 1 of the present invention, and the curing conditions and evaluation results for Comparative Examples 2 and 3 and Example 2 of the present invention. It is a thing. In addition, "Taber hardness" in the table indicates a haze value (haze value) (hereinafter the same).

[0031]

[Table 1]

In Table 1, according to Examples 1 and 2 of the present invention, the temperature atmosphere was lower than that of Comparative Examples 1, 2 and 3, and the time was shorter, but they were equivalent to those of Comparative Examples. It was confirmed that quality characteristics could be obtained. That is, according to Example 1, a polyurethane-based resin coating material (for example, "CP-605 liquid" manufactured by Nippon ARC Co., Ltd.) was applied to a plastic substrate made of plastic lenses and placed in a conventional thermosetting furnace. By applying the method of the present invention in which a near-infrared irradiation device is installed, it is necessary to heat-dry for 30-40 minutes in a temperature atmosphere of 80-90 ° C. when simply treating in a conventional thermosetting furnace. What
It was found that proper curing can be obtained by heating and drying for 5 to 10 minutes in an atmosphere of a temperature of 60 to 70 ° C.

Further, according to Example 2, a thermosetting acrylic resin paint (for example, "HC-1 manufactured by Seiko Kasei Co., Ltd."
00 liquid ", etc.) is applied to a plastic substrate made of an acrylic resin plate, and the method of the present invention, which is performed by installing a near-infrared irradiation device in a conventional thermosetting furnace, is applied to the conventional thermosetting furnace. 120-150 ° C when simply treating with
Which had been required to be dried by heating for 20 to 30 minutes in the temperature atmosphere of 8 to 10 in the temperature atmosphere of 70 to 80 ° C.
It was found that a proper curing can be obtained by heat drying for a minute.

Table 2 shows the curing conditions and evaluation results for Comparative Example 4 and Example 3 of the present invention, and the curing conditions and evaluation results for Comparative Example 5 and Example 4 of the present invention. Is.

[0035]

[Table 2]

In Table 2, according to Example 3 of the present invention,
A silicone resin coating material (for example, "C-343 liquid" manufactured by Nippon ARC Co., Ltd.) is applied to a plastic molded product made of the same plastic lens as in Example 1, and near infrared rays are put in a conventional heat circulation type curing furnace. By applying the method of the present invention in which an irradiation device is installed, heat drying for 60 to 180 minutes in a temperature atmosphere of 120 to 130 ° C. is required when simply treating in a conventional heat circulation curing furnace. 15 to 2 in the temperature atmosphere of 80 to 90 ° C.
It was found that a proper curing can be obtained by heating and drying for 0 minutes.

Further, according to Example 4, the above-mentioned polyurethane resin coating material, thermosetting acrylic resin coating material and silicone resin coating material are laminated and combined, and applied to a plastic molded article which is a polycarbonate resin plate. By applying the method of the present invention in which a near-infrared irradiation device is installed in a conventional thermal circulation type curing furnace, conventionally, a curing condition of high temperature and long time is required in the case of the same combination. However, it was found that proper curing can be obtained at a low temperature in a short time.

Table 3 shows Comparative Examples 6 and 7 and Example 5 of the present invention.
The curing conditions and the evaluation results for and are shown.

[0039]

[Table 3]

According to Example 5 shown in Table 3, a combination of the above-mentioned polyurethane resin coating material, thermosetting acrylic resin coating material and silicone resin coating material was laminated,
Application to the plastic film is performed at a low temperature for a short time by applying the method of the present invention using the third invention apparatus in which a near infrared irradiation apparatus is installed in a conventional heat circulation type curing tunnel furnace. It was found that a proper curing can be obtained with.

Table 4 shows the curing conditions and evaluation results for Comparative Example 8 and Example 6 of the present invention.

[0042]

[Table 4]

According to Example 6 shown in Table 4, a polyurethane resin coating material (for example, "CP-
605 liquid "or" CP-814 liquid ") and a thermosetting silicone-based resin coating material (for example," C-337 liquid "or" C-410 liquid "manufactured by Nippon ARCS),
Laminated with a combination of "CP-605 liquid" and "C-337 liquid" or a combination of "CP-814 liquid" and "C-410 liquid" (polyurethane-based resin paint is the lower layer) to form a plastic molded product. In the case of Comparative Example 8 shown as a conventional example, high temperature is obtained by applying the method of the present invention in which a near infrared ray irradiating device is installed in a conventional heat curing furnace. It was found that, while long-term curing conditions were required, proper curing could be obtained at low temperature in a short time.

That is, in Comparative Example 8, heat drying was required for 30 to 120 minutes in a temperature atmosphere of 90 to 120 ° C. in a heat circulation type curing furnace. 2 in the temperature atmosphere of 60 to 80 ° C. in the drying device which is installed the near infrared irradiation device in the circulation type curing furnace.
It was confirmed that proper curing could be obtained by heating and drying for 0 minutes.

[0045]

As described above, according to the present invention, when a thermosetting resin coating material is applied to a plastic base material and dried and cured, the plastic base material having a relatively low heat distortion temperature is heated. Since it can be dried in a short time in a low temperature atmosphere that does not deform, it forms a cured film without thermally deforming the plastic substrate itself or promoting molding strain due to heat. be able to.
Therefore, it can be suitably applied to a plastic substrate made of a plastic lens, a transparent resin plate, a plastic film, or the like.

[Brief description of drawings]

FIG. 1 is a front view showing an example of a first invention device of the invention devices.

FIG. 2 is a left side view of the same.

FIG. 3 is an explanatory diagram showing an example of a second invention device of the invention devices, in which (a) is an overall configuration diagram and (b) is a temperature distribution in relation to (a). It is a graph which shows a state.

FIG. 4 is an explanatory diagram showing an example of a third invention device of the invention devices, in which (a) is an overall configuration diagram and (b) is a temperature distribution in relation to (a). It is a graph which shows a state.

[Explanation of symbols]

11 Dryer 12 frame 13 Drying room 14 doors 15 hinges 16 Blower 17 Air supply duct 18 heater 19 filters 20 Near infrared heater (including near infrared lamp) 21 bottom 22 Exhaust box 23 Exhaust duct 24 exhaust box 25 Suction filter 26,27 damper 31 Dryer 32 heat curing furnace 33 space 34 Endless transportation means 35 conveyor belt 36,37 belt car 38 Near infrared heater (including near infrared lamp) 39 Start side shutter 40 End shutter 41 resin paint tank 42 racks 43 plastic substrate 51 Dryer 52 Roll on the starting side 53 Guide roller 54 resin paint tank 55 Heat curing furnace 55a space 56 Near infrared heater (including near infrared lamp) 57 Guide roller 58 Terminal side roll part 59 plastic base materials 60 drawer part 61 Inlet 62 Outlet

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F26B 13/10 F26B 13/10 E 15/18 15/18 B 21/04 21/04 A F term (reference) ) 3L113 AA02 AB02 AC08 AC10 AC31 AC36 AC48 AC49 AC67 BA26 BA32 DA10 DA24 4D075 AE03 BB24Z BB26Z BB33Z BB37Z BB38Z CA02 CA04 CA13 CA23 CA32 CA39 CB06 DA04 DA06 DA11 DA23 DB36 DB43 DB48 DB50 DC24 EA07 EA19 EB22 EB38 EB43 4F042 BA19 DB12 DB18 DB25 DB27 DB29 DB30 DB33 DB36 DB37 DF16

Claims (5)

[Claims] 1. A drying chamber provided with an opening / closing door for letting in and out a plastic substrate coated with a resin paint, and an air supply duct and an exhaust duct are provided to freely supply and exhaust air to and from the drying chamber. At least a blower is provided, and the drying chamber is provided with a near-infrared lamp installed in the drying chamber and a blowing of hot air generated through a heater and a filter arranged in order from the upstream of the air supply duct. Irradiation of near-infrared rays from an infrared heater is freely formed, and the air drawing from the drying chamber is newly taken in from the bottom side through the exhaust duct and part of the exhaust to the outside. A drying device for resin paint applied to a plastic base material, characterized in that the rest of the air and the air can be freely returned to the air supply duct side. 2. An endless transfer means for transferring a plastic base material coated with a resin coating material in a circulating heating atmosphere, and a near infrared lamp installed above the endless transfer means.
The above-mentioned near-infrared heater was provided in a thermosetting furnace, and the space in the thermosetting furnace was partitioned by at least one drying zone whose temperature was controlled separately. Dryer for resin paint. 3. A starting end side roll portion in which a sheet-shaped plastic base material before being coated with a resin coating material is wound in a roll shape,
A resin coating material tank for applying a resin coating material to the drawer piece portion drawn out from the starting end side roll portion side, a heat curing furnace for passing the drawer piece portion passing through the resin paint tank, and a drawer piece portion after passing through the end. And a near-infrared heater including a near-infrared lamp is installed, and the space in the thermosetting furnace is provided with a circulating heating atmosphere. A device for drying a resin coating material applied to a plastic substrate, characterized by being partitioned by at least one drying zone whose temperature is controlled separately. 4. A step of applying a thermosetting resin coating material to a heat-deformable plastic base material, and irradiating the plastic base material coated with the resin coating material with near infrared rays in a circulating heating atmosphere. A method for drying a resin coating material applied to a plastic substrate, comprising at least a step of curing the resin coating material. 5. The resin coating material is a coating layer of any one of a polyurethane resin coating material, an acrylic resin coating material, and a silicone resin coating material, or a combination of two or more kinds so as to form two or more coating layers. A method for drying a resin paint applied to the plastic substrate according to claim 4, which is applied.