JPS59100362A - Solar heat collecting plate - Google Patents

Abstract

PURPOSE:To form a solar heat collecting plate on a base material layer of high density polyethylene resin to be obtained by providing a coating layer, which is highly adhesive, inexpensive and having selective absorbing capacity of the sunlight, on the base material layer made of high density polyethylene resin, by providing the coating layer having the selective absorbing capacity of the sunlight by making the surface of the base material layer into an uneven face of less than 250mum. CONSTITUTION:The surface of a base material layer 1 having high density polyethylene resin for its main ingredient is provided with an uneven face 4 of less than 250mum. A first coating layer 2 contains metallic powder 5 showing roofing action and chrolinated polyethylene denatured alkid resin 6 as a binder for obtaining favorable adhesion with the high density polyethylene resin of the base material layer 1, a second coating layer 3 is the coating layer having selective absorbing capacity of the sunlight, permeability is comparatively favorable in a infrared ray sphere and is formed by a pigment consisting of the binder 7 whose adhesiveness with the first coating layer 2 is favorable and an oxide or a composite oxide 8 which absorbs the sunlight favorably and permeability to an infrared ray is comparatively favorable.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a solar heat collector plate for a solar heat collector as a household water heater.

Conventional structure and problems Conventional plastic solar heat collector plates are manufactured by blow molding high-density polyethylene resin filled with carbon black, etc., or the surface has a selective absorption ability for sunlight. There wasn't.

Also, as a means of achieving selective absorption ability on this surface, there was a method of painting, but sufficient adhesion could not be obtained due to the high non-adhesiveness of the high-density polyethylene resin of the base material layer.

Purpose of the invention The present invention improves adhesion to high density polyethylene resin,
The object of the present invention is to provide a solar heat collecting plate which is inexpensive and has a coating layer having the ability to selectively absorb sunlight on a base layer of high-density polyethylene resin.

Structure of the Invention In order to achieve the above object, the present invention provides a base material layer whose main component is a high-density polyethylene resin, with an uneven surface of 250 μm or less, and which has a selective absorption ability for sunlight on this base material layer. A coating layer having the following properties is provided.

DESCRIPTION OF EMBODIMENTS Above, embodiments of the tree invention will be explained. In the figure, three h are shown, and (1) is a base material layer whose main component is high-density polyethylene resin. On the surface of the base layer (1),
Two layers are formed: a first coating layer (2) and a second coating layer (3). These have the ability to selectively absorb sunlight.

The base material layer (1) mainly composed of high-density polyethylene resin was provided with a lower uneven surface (4) having a thickness of 250 μm on its surface. The first coating 1fj4 (2) is a coating layer that makes the surface of the base layer (1), which is mainly made of high-density polyethylene resin with a high thermal emissivity, a low-emissivity surface, and has a leafing effect. Metallic powder (5) shown and base material layer (1)
Contains chlorinated polyethylene modified alkyd resin (6) as a binder to obtain good contact with high density polyethylene super fat. The second coating layer (3) is a coating layer that selectively absorbs sunlight, has relatively good transparency in the infrared region, and has a binder ( 7) and a pigment consisting of an oxide or composite oxide (8) which absorbs light well and has relatively good transparency to infrared rays, and has a coating thickness not exceeding 1.5 μn1. is formed.

The operation of the coating system consisting of the first coating layer (2) and the second coating layer (3) will now be explained. The 8th side is the sunlight receiving surface, 1
The third side is a heat medium. A indicates sunlight incident on the surface of this solar heat collector plate. Sunlight A is absorbed by the second seedling layer (3) and converted into 1 part of heat. The converted heat is transferred to the first 8th layer (
2) The heat is conducted through the base material layer (1) and transferred to the heat medium l) surface side. On the other hand, regarding radiation loss from the surface, the second
Since the coating layer (3) is sufficiently transparent to infrared rays, it has a low emissivity, which is controlled by the properties of the metallic powder (5) of the first coating layer (2), and the base material layer ti+-t-t This 1
Therefore, it is difficult to impart sufficient selective absorption capacity.

High-density polyethylene resin, which is the material of the base layer (1),
Regarding adhesion with the first coating layer (2), adhesion was extremely difficult in the past, but this was solved by using the chlorinated polyethylene modified algide resin (6). Regarding contact with polyethylene resin, which is difficult to adhere to, the technology of using chlorinated polyethylene resin has been put to practical use in inks, etc., but most of them are made using relatively low molecular weight compounds (thousands of molecular stones) manufactured by a solution method. ) and has a high chlorine concentration of 66% or more, and has good adhesion to low-medium pressure polyethylene resin, but there are problems with adhesion to high-density polyethylene resin. In this example, molecules manufactured by the aqueous suspension method (i.
A chlorinated polyethylene modified alkyd resin, which is a mixture of chlorinated polyethylene resin and alkyd resin, was used. Since this 3M bare polyethylene modified alkyd resin (6) has a low level of chlorine metal, it hardly impairs the leafing properties of the metallic powder (5). In addition, since the molecular weight is large and there are more structurally similar parts to that of high-density polyethylene resin, it has good adhesive properties.

In addition, in order to maintain the leafing properties of the metallic powder (5) while sufficiently improving the adhesion of the first PA j* (2), chlorinated polyethylene modified alkyd super fat (6) is added.
Epoxy resin was added to. The epoxy resin maintains good leafing properties of the metallic powder (5),
The metallic powder (5) itself stably adheres into the first covering layer (2).

As the metallic powder (5), it is possible to use metals with adhesive properties such as copper or aluminum, or in this example, coarse-grained aluminum powder was used. If the mixing ratio of metallic powder (5) is 1 to 1 when no special treatment is performed on the base material, it is best to use the metallic powder in a range of 5 to 4 Q wt.%. Desired (-< is in the range of 10 to 25 wt.% or gives optimum leaf ink properties and adhesion.

Moreover, when obtaining a surface with low infrared emissivity by the J-th coating layer (2), the higher the blending ratio of the metallic powder (5), the better. On the other hand, with respect to the adhesion with the base material layer (1), conversely, if the blending ratio of the metallic powder (5) is reduced, the adhesion becomes worse. 2 In order to solve this problem, a fine uneven surface (4) of 250 μnl or more in size is formed on the surface of the base layer (1) of high-density polyethylene resin. By increasing the amount of metallic powder (5) in proportion to the strength of the force, it was possible to lower the emissivity without reducing the tightness.The first coating layer (2) ) is formed, this first coating layer (2
) can be provided with a second covering layer (3) having the ability to selectively absorb sunlight, which has conventionally been applied only to metal surfaces.

The second coating layer (3) includes Fe, Mn, Cu,
<2r.

A binder (7) consisting of one or more oxides or composite oxides (8) selected from the group of Ni and Co and one or more synthetic resins selected from the group of acrylic resins, fluorocarbon resins, urethane resins, and alkyd resins. ) was the main component.

The pigment made of the metal oxide or composite oxide (8) has almost no infrared absorption and good sunlight absorption ability. These oxides or composite oxides (8) have 0.
Particles having a particle size range of 0.01 to 0.5 μn were used. In the case of this particle size, the effect of scattering and absorbing sunlight well is remarkable. Acrylic resin, fluorocarbon resin, urethane resin, and alkyd resin all achieve good adhesion with the first coating layer (2).

The thickness of the second coating (3) was determined not to exceed 5 μm since the selective absorption ability of sunlight would deteriorate if it was too thick.

The evaluation results of the materials used for each coating layer are shown below.

Made of high density polyethylene resin (contains 1.5wt% carbon black), 95mm x 1g o
A board with dimensions of ram X 1011M+ was used as a test piece. This is hollow inside and was molded by blow molding. Regarding this test piece, the front and back sides are 95mm x 95mm (divided into D4 pieces (DV'-), and 40°60.80mm for the blow molding mold.
, and 100 mesh, using sand-frust molds with particle sizes of 100 and 100 mesh, and molding was carried out in a state in which minute irregularities were formed in each of the four zones on the front and back sides.

When the surface unevenness was evaluated using a scanning electron microscope, it was found to be 40
350μm for mesh, 250μm for 60 mesh1
180μm for 80 mesh, 150 for 100 mesh
An uneven surface with a μm average was formed.

Table 1 Formula of first coating layer (parts by weight) 1) T;! 4-Yo Aluminum Co., Ltd.: Alpaste "0100X" C (trade name) was used.

2) Osaka Soda Co., Ltd.: Emul Lux “P-35” (
Product name) is used.

3) is Yuka Shell Epoxy Co., Ltd.: Epicoat R821
Uses 3J (product name).

4) uses "toluene".

On the base material layer (1), a paint having the composition shown in Table 1 is dispersed and prepared in a ball mill for 1 hour, and the paint is coated on the base material layer (1) with a coating composition shown in Table 1.
A coating thickness of 20 μm was applied and dried at 60° C. for 30 minutes. Table 2 shows the evaluation results of the characteristics of this first treated layer (2). The adhesion test in the table was carried out by cellophane tape peeling test, where X indicates peeling and △ indicates that dotted peeling occurred.

Table 2 Evaluation results of the first coating layer Next, a second coating layer (3) consisting of a top coat of the composition shown below was coated on each of the same coating layers. After dispersing and blending the paint in a ball mill for 24 hours, a curing agent was added and diluted with approximately twice the amount of solvent. , at 60°C, 3
Table 3 shows the results after drying for 0 minutes.

+11 pigment: Dainichiseika Chemical Co., Ltd. 1' Dipyroxide Color 09550-1''J (trade name) 50 parts.

(2) Synthetic resin: Asahi Glass Co., Ltd. [Lumifron River-)-2
Use 1 part of 00J (product name) 100 weight.

(3) Solvent: ``Methyl in butyl ketone:xylene-1:1-200 parts by weight was used.

(4) Curing agent 2 14.8 parts by weight of "Coronate EH" (trade name) manufactured by Nippon Polyurethane Industries Co., Ltd. was used.

Looking at the results in Table 3, it appears that the binder (7) in the second coating layer (3) is partially hidden in the first coating layer (2) compared to Table 2. This also contributed to the improvement of the 4 cases of close contact.

In addition, a simulation evaluation of a natural circulation solar water heater showed that the heat collection efficiency was approximately 5% higher than when using an untreated plastic solar heat collection plate, and the annual heat collection amount was also lower. The result was that the heat collection capacity increased by approximately %.

Further, the chlorinated polyethylene resin has a large molecular weight,
Due to the high solution viscosity, there is a limit to its compatibility with Ike no Wajō fat, but in order to achieve stable physical properties as a coating system, it may be used in combination with an acrylic resin.

As described above, in this example, by using a cost-effective coating method, highly reliable selective absorption ability was achieved on the base material layer (1) of high-density polyethylene resin, which was difficult to adhere to in the past. Because we were able to provide a corner coating layer, compared to conventional plastic solar heat collection plates that do not have selective absorption treatment, the radiation loss from the heat collection plate surface is reduced by half, resulting in improved efficiency. Improved.

Effects of the Invention As described above, the present invention provides the following various excellent effects.

■ Improved efficiency of solar heat collector plates can be achieved by selectively absorbing sunlight.

(2) Since the surface of the base layer is provided with an uneven surface of 250 μm11 or less, the leafing property can be improved without deteriorating the adhesion with the first coating layer.

■ Conventional solar heat collecting plates had the drawback of deteriorating weather resistance and causing chalking, but with the present invention, this is completely prevented by implementing a high 4 weather coating, making it highly reliable as a solar heat collecting plate. You can get sex.

■ Since expensive metal plates etc. are not used, an inexpensive configuration is possible.

■ The m2 coating layer, which is in direct contact with the outside air, can be made of a material with good rust prevention properties, so even if used in coastal areas, it will not rust and can be expected to have excellent durability.

[Brief explanation of the drawing]

The drawing is an enlarged sectional view showing one embodiment of the present invention. (Moon: base material layer, +21: first working layer, (3)...
Second coating layer, (4)...Irregularities, (5)...Metallic powder, (6)...Chlorinated polyethylene modified alkyd resin, (7)...Binder, (8)...Oxide or composite oxide. Agent Patent attorney Shima - Public procedure amendment (Method 1, Case indication 1982 Patent application Junko 211560 No. 2, Title of invention Solar heat collecting plate 11, -' 4. Agent 5 Amendment order Or the day of notification of reasons for refusal ＼4 Showa, 3rd year of 8th year
Month 29F] 6 In the specification to be amended, column 7 of the detailed description of the invention and pages 9, 10, and 12 of the statement of contents of the amendment are amended as per paper 91J. (Engraving number: No change to the inner container.) Table 1: Composition of the first layer & layer (parts by weight) 1) is manufactured by Toyo Aluminum Co., Ltd.: Alpace) Rolo
Use oXJ (product name). 2) Osaka Soda Co., Ltd.: Emullux rP-35J (
Product name) is used. 3) is Yuka Shell Epoxy Co., Ltd.: Epicor) r828
Use J (product name). 4] uses “toluene”. On the base layer (1), a paint having the composition shown in Table 1 is dispersed and mixed in a ball mill for 1 hour to form a coating material on the base layer (1) for about 10 to 10 minutes.
It was applied to a coating thickness of 20 μm and dried at 60° C. for 30 minutes. Table 2 shows the evaluation results of the characteristics of this first covered layer (21).The adhesion test in the table was carried out using cellophane tape peeling test. Table 2 Evaluation results of the first coating layer Next, a second coating (3+) consisting of a top coat of the composition shown below was applied on each of the same wave ridge layers. After dispersing with a ball mill trowel for 244 hours, a curing agent was added, diluted with approximately twice the amount of solvent, and applied to a coating thickness of approximately 1.5 μm on the coating shown in Table 2, and heated at 60°C. Table 3 shows the results after drying for 30 minutes.

Claims (1)

[Claims] (1) A base material layer containing high-density polyethylene resin as a main component, and a coating layer provided on this base material layer and having a selective absorption ability of sunlight, the surface of the base material layer being 250%
A solar heat collector plate with an uneven surface of μn1 or less. (21) The first coating layer contains a chlorinated polyethylene-modified alkyd resin as a binder for the metallic powder as the coating layer, and the second coating layer has the ability to selectively absorb sunlight. The solar heat collecting plate according to item 1.