JPH04337364A - Coating composition - Google Patents

Abstract

PURPOSE:To provide the title composition for coating material having infrared screening effect. CONSTITUTION:The objective composition can be obtained by dispersing (A) diamond powder pref. 0.01-100mum in mean particle size in (B) a binder. The present composition is excellent in infrared screening effect leading to exceptionally outstanding temperature rise-suppressive effect, also causing no impairment of its transparency.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating composition, and more particularly, it is an object of the present invention to provide a coating composition for paints, etc., which has an infrared blocking effect.

0002

[Prior Art] In general, sunlight that reaches the earth's surface includes ultraviolet rays (actinic rays) having a wavelength range of 290 to 400 nm, visible light having a wavelength range of 400 to 800 nm, and ultraviolet rays having a wavelength range of 800 nm (0.8 μm) to 1 mm. There is infrared rays (heat rays) that have a wavelength range, and among these, infrared rays further have approximately 2 wavelength ranges.
．． Although it is divided into near infrared rays of 5 μm or less, normal infrared rays of 2.5 to 25 μm, and far infrared rays of about 25 μm or more, it is known that the wavelength region of about 2.5 μm or less occupies most of the radiation energy.

Up until now, studies have been conducted on the heat absorption efficiency of various inorganic black pigments such as iron oxide and copper oxide for infrared rays, especially near infrared rays, from the perspective of utilizing solar heat. However, from the perspective of energy efficiency, research has begun to be conducted on how to protect indoor spaces and vehicle interiors from temperature rises caused by solar energy.

Conventionally, the following methods have existed as means for protecting against infrared rays. ■ Silver, aluminum,
Metal films or metal oxide films are formed on the surfaces of glass, ceramics, metals, films, etc. using chemical plating, vacuum evaporation, sputtering, CVD, ion plating, etc. with metals such as zirconium, cerium, and titanium. How to form.

(2) A method in which infrared reflective pigments such as lead chromate, molybdate red, and cadmium sulfide are kneaded into the film, or glass, films, etc. are coated with a paint containing the infrared reflective pigments.

[0006]

However, each of the above conventional techniques has the following drawbacks.

[0007] ■ Methods of forming metal films or metal oxide films on the surface of a substrate using chemical plating methods, vacuum evaporation methods, sputtering methods, etc. First, chemical plating methods use harmful substances such as cyanide, so they are not suitable for industrial use. With scale, waste liquid treatment and safety management require a lot of effort and are not economical.
On the other hand, vacuum evaporation methods, sputtering methods, and the like require large-sized forming apparatuses, increase production costs, and have limitations on the shape of the substrate to which they can be applied.

[0008] In the method of kneading an infrared reflective pigment into a film or coating it as a paint component, considerable coloring is unavoidable at a concentration that can provide sufficient infrared reflective performance, and transparency is reduced. This has the disadvantage of making the interior of the room or car dark.

The present invention has been made in view of the above circumstances, and has not only sufficient infrared rays, especially near infrared rays blocking effect, but also the accompanying effect of suppressing temperature rise. An object of the present invention is to provide a coating composition that does not impair transparency.

0010

[Means for Solving the Problems] As a result of extensive research in order to solve the above problems, the present inventors discovered that diamond powder has an excellent infrared shielding effect, and based on this, the present invention was completed.

That is, the present invention is a coating composition in which diamond powder is dispersed in a binder, and in a preferred embodiment, the average particle diameter of the diamond powder is 0.
01 to 100 μm.

The present invention will be explained in detail below. The diamond powder used in the present invention is made of carbon, which has an atomic number of 6 and belongs to Group 4 of the periodic table, has a neutral electronegativity, and has a jungle gym-like structure with atoms bonded together through covalent bonds. have. Diamond is also transparent, has the highest Mohs hardness of any material on earth, and has excellent electrical insulation properties.

[0013] A diamond crystal is a typical dative bond crystal in which each carbon atom shares each electron. Impurities contained in natural diamonds include N atoms and B atoms,
These impurities often partially replace C atoms in the diamond lattice to form a solid solution. Furthermore, diamonds are generally classified into type I and type II, and further divided into type a and type b, respectively. This classification depends on the content of N atoms and their existence, or whether or not B atoms are included. In type Ia, N atoms exist as a precipitated layer between crystal lattices in the form of a thin film parallel to the {100} plane of the crystal. In type Ib, N atoms replace C atoms constituting the diamond crystal and form a solid solution. The N atom content of IIa and IIb is extremely small, and like the type Ib, C atoms are substituted and dissolved in solid solution. Most naturally occurring diamonds are type Ia. High-pressure synthetic diamond using a catalytic metal is type Ib and contains many N atoms, but due to the environment in which diamond grows, N
By removing atoms, type IIa diamond or type IIb diamond added with type B atoms can be synthesized. Any of the types of diamond powder described above can be used in the coating composition of the present invention.

[0014] Furthermore, the average particle diameter of the diamond powder is 0.01 to 100 μm, preferably 0.1 to 50 μm.
Thicknesses in the μm range can be advantageously used in view of the coating finish.

[0015] Next, the content of diamond powder in the coating composition of the present invention is not particularly limited, but when considering the infrared ray blocking effect and the binder component, the content of diamond powder in the entire coating composition should be 0.
A range of 1 to 50% by weight, preferably 1 to 30% by weight is selected depending on the purpose.

Similarly, the binder to be applied to the present invention is one that has good heat resistance, weather resistance, adhesion, etc. when used as a coating agent, and preferably has properties such as transparency. For example, acrylic resins (acrylic acid, methacrylic acid or esters thereof, β-hydroxyethyl acrylate or methacrylate, β-hydroxypropyl acrylate or methacrylate, 2-methoxyacrylate or methacrylate, 2-ethoxyacrylate or methacrylate, acrylonitrile) , methylol acrylamide, glycidyl methacrylate, vinyl acetate, styrene, etc.), vinyl acetate resin, ethylene-vinyl acetate resin, cellulose resin (ethyl cellulose, nitrocellulose, etc.), alkyd resin, urethane resin, polyester resin, butyral resin , ketone resin, amino resin, epoxy resin, phenolic resin, urea resin, melamine resin, silicone resin, modified silicone resin (alkyl resin, acrylic resin, phenolic resin,
In addition to fluororesins, alkali silicates such as sodium silicate, inorganic colloids such as silica sol, alkyl silicates such as tetraethoxysilane, phosphates such as aluminum phosphate, Examples include organometallic compounds such as tin acetate, metal alkoxides, and aluminum chelates.

[0017] These binders also include xylene,
Aromatic hydrocarbons such as toluene, alcohols such as methanol, ethanol, propyl alcohol and n-butanol, esters such as methyl acetate and butyl acetate, halogenated hydrocarbons such as methylene chloride and carbon tetrachloride, n- It is used by dissolving it in saturated hydrocarbons such as hexane, ligroin and mineral spirits, ketones such as methyl isobutyl ketone and acetone, glycol ethers such as methyl cellosolve and ethyl cellosolve, and water or by emulsifying it.

[0018] The diamond powder needs to be uniformly dispersed in the binder, and for this purpose, for example,
Ball mills, attritors, sand gliders, roll mills, high-speed impeller mills, jet mills, kneaders, paint seekers, homogenizers, ultrasonic dispersers, etc. are used.

Furthermore, the coating composition of the present invention includes:
Depending on the intended application, customary additives used in the coating sector, such as pigments, fillers, hardeners (including coupling agents), plasticizers, thickeners, coalescents, freeze stabilizers, preservatives. Appropriate amounts of the following can be added. For example, pigments include inorganic pigments such as titanium dioxide, iron oxide, lead oxide, manganese oxide, chromium sulfide, cobalt sulfide, etc., and fillers include glass fiber, alumina fiber, talc, zeolite, etc. Examples of curing agents include phosphates, isocyanates, and silane coupling agents.

The coating composition of the present invention can be applied to glass, plastics, polymeric films, metals, rubber, etc. by conventional methods such as spray coating, spin coating, roll coating, doctor blade coating, dip coating, brush coating and rotor coating. It can be applied to a variety of substrates such as ceramics, textiles, cloth, and paper, forming a continuous surface film with an infrared blocking effect. In particular, it is advantageous to apply it to the outer surface of substrates that require brightness, such as automobile glass, window panes, roofs of sunrooms and terraces, and vinyl greenhouses.

[0021] The thickness of the film at this time is not particularly critical, but about 3 to 1000 μm is sufficient. However, it can be made thicker for applications that do not require precise dimensions.

[0022] Here, the features of the present invention will be described in detail: (1) When the cutting power of zirconium oxide, which has been conventionally known as a typical infrared cut agent, in the near-infrared region of 1 μm is set to 1, as a filler, While talc and aluminum have 0.97 times the cutting power, diamond powder has approximately twice the cutting power and has a strong infrared shielding effect on the coated substrate. can be granted.

■ In the near-infrared region of 1 to 2.5 μm, where thermal energy is higher, the cutting power of zirconium oxide gradually decreases, whereas diamond powder, like aluminum, maintains the same level of cutting power at a wavelength of 1 μm. Moreover, diamond powder has a pale olive color and has high visible light transmittance, so the brightness is less impaired than when a vapor-deposited metal film or metal oxide film is used.

Next, the diamond powder according to the present invention is
A transmission spectrum diagram is shown to show how superior the cutting effect in the near-infrared region is compared to conventional infrared protection materials. The samples used were diamond powder (3.5 μm), talc powder (3.8 μm), metal aluminum powder (9.4 μm), and zirconium oxide powder (4.2 μm), and the KBr method (sample 0.7 mg) was used.
/300mgKBr). ■ Diamond powder (Figure 1) ■ Talc powder (Figure 2) ■ Metallic aluminum powder (Figure 3) ■ Zirconium oxide powder (Figure 4) As is clear from the transmission spectrum diagram, the diamond powder according to the present invention is different from conventional infrared protection materials. It has been demonstrated that it has a higher infrared ray cutting effect compared to the previous one.

The present invention will be explained below using examples. Incidentally, the blending ratio is in weight %.

Example 1 (A) Nitrocellulose
18
(B) Isopropyl alcohol
8
butyl acetate
2
4 Ethyl acetate

16 Ethyl cellosolve

8 Toluene

20 (C) Diamond powder (average particle size 0.1 μm)
6 (Method) (A) was dissolved in (B), and (C) was added thereto and dispersed using a ball mill.

Example 2 (A) Silicone varnish (solid content 50%)
80 (B) Diamond powder (average particle size 3 μm)
20 (Method) (B) was added to (A) and dispersed using a ball mill.

Example 3 (A) Ketone resin (trade name: Hilac 110)
6 (B) Acetylacetone
60 Ethyl acetoacetate
30 (C) Diamond powder (average particle size 0.5 μm)
4 (Method) (A) was dissolved in (B), and (C) was added thereto and dispersed using a ball mill.

Example 4 (A) Water

30 (B) Silica

39 Sodium aluminate
1.5 Diamond powder (average particle size 5 μm)
26.5 (C) Colloidal silica (solid content 15%)
3 (Method) To (A) and (B) were added and suspended, (C) was added and dispersed using an ultrasonic disperser.

Example 5 (A) Silicone urethane varnish (solid content 50%)
20 (B) Fine particle zinc oxide

3 Fine particle titanium oxide
3 Diamond powder (average particle size 10 μm) 4
toluene

66 (C) Isocyanate

4 (Method) (B) was added to (A) and mixed well, and after stirring and dispersing with a sand glider, (C) was added.

Example 6 (A) Acrylic acid/2-hydroxyethyl acrylate/88 methyl methacrylate/butyl acrylate copolymer emulsion (solid content 40%) (B) Diamond powder (average particle size 25 μm) 1
2 (Method) (B) was added to (A) and dispersed using a colloid mill.

(Comparative Experiment) The coating composition obtained according to the present invention and a conventional coating composition were compared in terms of infrared ray cutting effect and temperature rise suppressing effect.

<Infrared cutting power test> Sample (a) Coating composition of Example 1 of the present invention (B) Conventional coating composition of Example 1 of the present invention excluding diamond powder

Experimental method A sample was applied to a slide glass with a thickness of 0.5 mil using a doctor blade, and the sample was placed in the light receiving section of an integrated luminometer, and an infrared lamp was used to irradiate it with infrared rays for 5 minutes. The infrared transmittance was calculated by irradiating the light, reading the counts on the illuminance meter, and calculating the inverse of the infrared cut rate.

As a result of the experiment, the infrared cut rate of the product of the present invention was 92%, while
That of the conventional product was 13%, and it was demonstrated that the product of the present invention has an excellent infrared ray cutting effect.

<Temperature Rise Suppression Test> Samples The same inventive product (A) and conventional product (B) as those used in the above infrared cutting power test were used.

[0037] Experimental method: A glass box with a length of 30 cm was made, and a sample was applied to the outside of the box by a spray method and dried to form a coating film.The glass box was then exposed to the scorching midday sun for 60 minutes. The box was left for a minute, and the temperature difference between the inside temperature of the box and the outside temperature at that time was measured.

As a result of the experiment, the temperature difference for the product of the present invention was +3°C, while the temperature difference for the conventional product was +12°C, indicating that the product of the present invention was significantly more effective in suppressing temperature rise than the conventional product. It turned out that there was.

[0039]

Effects of the Invention According to the present invention, not only is the infrared ray blocking effect excellent and the resulting temperature rise suppressing effect extremely excellent, but also the transparency is not impaired.

[Brief explanation of drawings]

Claims (2)

[Claims] 1. A coating composition comprising diamond powder dispersed in a binder. [Claim 2] Diamond powder has an average particle diameter of 0.0.
The coating composition according to claim 1, which has a particle size of 1 to 100 μm.