JPH0196280A - Infrared ray absorber - Google Patents

Abstract

PURPOSE:To obtain the titled absorber having excellent heat resistance and designability, by forming the second coating layer containing a specific organosilicon high condensate as a binder and an inorganic pigment on a coating layer containing a calcined ceramics based pigment using the above-mentioned binder. CONSTITUTION:A mixture of an organosilicon compound expressed by formula I (R is 1-8C hydrocarbon) and/or a low condensate thereof with an organosilicon compound expressed by formula II (R' is 1-12C hydrocarbon) and/or a low condensate thereof is initially hydrolyzed in the presence of an acid catalyst and the pH thereof is adjusted to >=7 with an alkaline substance to condense the resultant hydrolyzate. A composition consisting of (A) 100pts.wt. organosilicon high condensate without containing any terminal silanol group obtained as described above, (B) 30-300pts.wt. extender pigment selected from mica, talc, etc., and (C) 30-300pts.wt. calcined ceramics pigment is used to form the first coating layer. The second coating layer is formed by using a composition containing 100pts.wt. component (A), 30-300pts.wt. component (B) and (D) 10-200pts.wt. inorganic colored pigment.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an infrared absorber, and more particularly to an infrared absorber that has excellent heat resistance, has an arbitrary color tone on its surface, and has an extremely excellent design.

Conventional infrared absorbers are formed from a coating layer using a specific fired ceramic pigment that has infrared absorption ability, so the color tone of the coating is limited to black or deep color, and the design is poor.

Therefore, the inventor of the present invention has conducted extensive research with the aim of developing an infrared absorber that does not have the above-mentioned drawbacks.
On top of the first coating layer formed from a coating composition containing a specific silicate polymer as a binder component, a specific extender pigment, and a specific fired ceramic pigment having infrared absorbing ability, The above object can be achieved by forming a second coating layer using a coating composition containing a silicate polymer as a binder component, and the above-mentioned extender pigment and an inorganic pigment that imparts a desired color tone. This discovery led to the completion of the present invention.

Thus, according to the present invention, (1) an organosilicon compound represented by the following general formula [A] and/or a low condensate thereof, and R-0-5t-0-R (where R has 1 to 1 carbon atoms) 8 charcoal 0
Hydrogen group) ... (A) The following - tubular type (
Organosilicon compound represented by B) and/or its low condensate R' R-0-5i-OR (wherein R' has 1 to 120 carbon atoms)
hydrocarbon group, R is the same as above)
... CB) in the presence of an acid catalyst, and then using an alkaline substance to raise the pH to 7 or higher and condense the resulting organosilicon high condensate without a silanol group at the molecular end. 30 to 300 parts by weight of at least one extender pigment selected from mica, talc, calcium carbonate, clay, pallite, and bentonite, and 30 to 300 parts by weight of a fired ceramic pigment. On the first coating layer formed from the coating composition, (IV) the above (1) organosilicon high condensate 100 parts by weight (V) the above (II) extender pigment 30 to 300 parts by weight, and (Vl) An infrared absorber is provided in which a second coating layer is formed with a coating composition containing 10 to 200 parts by weight of an inorganic colored pigment.

The infrared absorber obtained by the present invention includes stainless steel,
It is obtained by overcoating a second coating layer on top of a first coating layer formed on a metal substrate such as steel, iron, copper, or aluminum.It has excellent infrared absorption ability and is heat resistant. It has excellent hardness and chemical resistance, and can have an appearance in any color tone, so it can give an excellent design feel.

In the present invention, the organosilicon high condensate (I) that does not have a silanol group at the molecular terminal and is used as a binder component of the coating composition forming the first coating layer has the following general formula [A]
An organosilicon compound and/or a low condensate thereof represented by R-0-3i -0-R (where R is a carbon number 1 to 8 carbon hydrogen group)...(A) The following - Organosilicon compound represented by the tubular formula (B) and/or its low condensate R' R-0-Sj-0-R (where R' is a hydrocarbon group having 1 to 12 O carbon atoms, It is obtained by hydrolyzing a mixture consisting of (same) ...CB) in the presence of an acid catalyst, and then adjusting the pH to 7 or higher using an alkaline substance and condensing it.

R in the organosilicon compound represented by the above general formula [A] is the same or different hydrocarbon group having 1 to 8 carbon atoms, and examples of the hydrocarbon group include methyl, ethyl, propyl, hexyl, etc. , aryl groups such as phenyl, tolyl, and xylyl, and cycloalkyl groups such as cyclohexyl, cyclobutyl, and cyclopentyl.

Specific examples of the compound include tetramethoxysilane, tetraethoxysilane, tetrapropioxysilane, tetrabutoxysilane, and tetraphenoxysilane. Moreover, the low condensate means an oligomer having a degree of condensation of 10 or less.

Further, R in the organosilicon compound represented by the above-mentioned form CB) is the same as in the case of the above-mentioned form (A). On the other hand, R' is a hydrocarbon group having 1 to 12 carbon atoms bonded to silicon through a carbon-silicon bond, and examples of the hydrocarbon group include alkyl groups such as methyl, ethyl, propyl, hexyl, and octyl, phenyl, tolyl, and xylyl. , a teryl group such as naphthyl, and a cycloalkyl group such as cyclohexyl, cyclobutyl, and cyclopentyl.

Specific compounds include methyltrimethoxysilane,
Examples include methyltriethoxysilane, phenyltrimethoxysilane, and phenyltriethoxysilane.

When condensing the organosilicon compounds represented by the above-mentioned formats (A) and CB) and (or) a mixture of their low condensates, the mixture of the compounds and (or) low condensates is first dissolved in a water-soluble solvent such as alcohol. It is preferably added to p116-based solvents, cellosolve-based solvents, cellosolve acetate-based solvents, glyme-based solvents, etc., in the presence of mineral acids such as hydrochloric acid, sulfuric acid, phosphoric acid, or organic acids such as formic acid and acetic acid.
Below, 0.2 per mole of RO group bonded to Si
Add water at a ratio of ~2 mol and heat at 20 to 100℃ for 3
The reaction is carried out under stirring for about 0 minutes to 10 hours to carry out hydrolysis and condensation reactions.

Next, inorganic bases such as sodium hydroxide and potassium hydroxide, alkali metal or alkaline earth metal salts of weak acids such as boric acid and molybdic acid that are soluble in water-soluble solvents and exhibit basicity (e.g. sodium borate, molybdenum aliphatic amines such as monoethylamine, diethylamine, and triethylamine, and alkaline substances such as ammonia to adjust the pH of the system to 7 or higher, preferably 7.5 to 8.5, and to control the condensation reaction. Allow to proceed for 5-10 hours. After the reaction is completed, the desired organosilicon high condensate can be easily obtained by removing remaining water by distillation, azeotropy, or the like.

When obtaining a high condensate using the organosilicon compounds represented by the above-mentioned formats (A) and (B), it is appropriate to mix both components in the following proportions based on weight.

Compound of general formula (A): 5 to 95% by weight, preferably 20 to 80% by weight Compound of general formula (B): 5 to 95% by weight, preferably 20 to 80% by weight In the above formulation, the amount of compound (A) If it is less than 5% by weight, that is, if the amount of the compound (CB) exceeds 95% by weight, the curability of the film formed using this condensate will be poor. In addition, if the amount of the (B) compound is less than 5% by weight, that is, if the amount of the (A) compound exceeds 95% by weight, the film will easily peel off when thickly coated using this condensate. Tend.

The thus obtained high condensate is a three-dimensional clamped product with a degree of condensation of at least 20 or more and a molecular weight of about 3,000 or more, and has sufficient performance as a binder for the coating composition, and can be used as a clear coating as it is, for example. Even if it is 50-1
It is possible to form a film with a film thickness of approximately 00μ.

The above-mentioned organosilicon high condensate does not have a silanol group that easily undergoes condensation reactions at the end of the molecule, so it has very good storage stability. Since the crosslinking density can be adjusted appropriately by changing the blending ratio, the result is a clear coating with an excellent inorganic coating that has an excellent balance between curability and thick coating, that is, does not peel off during curing. However, it is possible to form a thick film of 50 to 100 μm. Furthermore, the main skeleton of the cured film is 15i-0-5i-condensation, so it has heat resistance, corrosion resistance,
It has excellent properties such as chemical resistance and weather resistance.

The above-mentioned organosilicon high condensate is soluble in organic solvents and is usually produced with a solid content in the range of 10 to 30% by weight, or 15 to 20% by weight.

The extender pigment (n) used in the present invention is at least one selected from mica, talc, calcium carbonate, clay, pallite, and bentonite, which are commonly used in paints, and these are used in combination with the organosilicon high condensate. This has the effect of absorbing expansion and contraction during film formation and at the same time preventing the occurrence of flakes and blisters during baking and drying.

The amount of the extender pigment to be used is 30 to 300 parts by weight, preferably 50 to 200 parts by weight, per 100 parts by weight of component (1).If it is less than 30 parts by weight, cracking of the film will occur due to expansion and contraction of the film. On the other hand, if the amount exceeds 300 parts by weight, the coating composition tends to thicken and precipitate, and the storage stability deteriorates.

Furthermore, it is essential that the fired ceramic pigment used in the present invention has infrared absorption ability.

The infrared absorption ability here refers to the first coating layer,
It refers to performance such that the spectral reflectance in the wavelength range of 2.5 μm to 25 μm is 10% or less.

Examples of fired ceramic pigments having infrared absorption ability include clay-silica-iron oxide ceramics and transition element oxide ceramics.

Clay-silica-iron oxide ceramics can be obtained, for example, by sintering 35% by weight of clay, 20% by weight of calcined clay, 25% by weight of silica, and 20% by weight of iron oxide at 1150°C.

In addition, transition element oxide ceramics, for example, F
ezOz 85% by weight, MnozlO% by weight, CuO3
wt% formulation or Fetch 25wt%, Mn0z5
5 wt%, Co010 wt%, Cu010 wt% formulation or Mn0z85 wt%, 0005 wt%, Cu0
A 10% by weight formulation can be obtained by sintering at 1200°C.

The amount of the fired ceramic pigment used is 100% of component (1).
30 to 300 parts by weight, preferably 50 parts by weight
~200 parts by weight. If the amount used is less than 30 parts by weight, the infrared absorption ability will be poor, and if it exceeds 300 parts by weight, the composition will tend to thicken and precipitate, resulting in poor storage stability.

Next, the inorganic coloring pigment that is a component of the coating composition that forms the second coating layer is used for the purpose of coloring the coating in an arbitrary color tone, and aluminum powder, stainless steel powder, copper powder, brass powder, etc. So-called normal inorganic coloring pigments other than metal powders such as, for example, can be applied. Specifically, titanium oxide, Penkara,
Ochre, carbon black, etc. are used alone or in combination to obtain a predetermined color tone.

The amount of the inorganic colored pigment used is 10 to 200 parts by weight, preferably 20 to 150 parts by weight, per 100 parts by weight of component (1).
Parts by weight. If the amount used is less than 10 parts by weight, the first coating layer cannot be hidden, and the desired color tone cannot be obtained.
If it exceeds 200 parts by weight, the composition tends to precipitate, resulting in poor storage stability.

The thickness of the first coating layer constituting the infrared absorber of the present invention is from 10μ to 300μ, preferably from 30μ to 10μ.
It is in the range of 0μ. If the film thickness is less than 10μ, the infrared absorption ability will be poor, and if it exceeds 300μ, it will be distorted due to thermal shock.
Defects such as cracks and peeling occur in the film.

The thickness of the second coating layer constituting the infrared absorber of the present invention is from 10μ to 200μ, preferably from 20μ to 100μ.
is within the range of If the film thickness is less than 10 μm, the color tone of the first coating layer cannot be hidden, and if it exceeds 200 μm, the infrared absorption ability decreases.

The coating composition forming the first coating layer of the present invention contains the above components (I) to (■), and the coating composition forming the second coating layer contains the above components (IV) to (Vl). Although these are essential components, a pigment dispersant, a pigment antisettling agent, etc. can also be added as necessary.

The present invention will be explained in more detail below with reference to production examples and examples.

In the Production Examples and Examples, "parts" and "%" refer to "parts by weight" and "% by weight" unless otherwise specified.

Production Example 1 In a reaction vessel, 62 g of tetraethoxysilane, 125 g of methyltriethoxysilane, and 187 g of ethyl alcohol
was added, and the contents were heated to 80° C. while stirring, and then 30 g of 0.2N hydrochloric acid was added and reacted at 80° C. for 10 hours. Next, 30 g of triethylamine was added to this reaction product to raise the pH to 7 or more, and a linearization reaction was carried out at 80° C. for 2 hours. Thereafter, benzene was added and the solvent was removed until the nonvolatile content became 36%.

The reaction product (varnish) thus obtained was transparent and had a viscosity of 5.0 centivoise.

Production example 2 100 parts of the above varnish and 72 mica in a paint shaker
Part, fired ceramic pigment (MnOz85%, Co0
5%, Cu010% fired at 1200°C) 65
Part, Pigment dispersant (Disparon 6900-IOX) 2
15 parts of xylene were added thereto, and dispersion was carried out for 30 minutes to obtain coating composition A.

Production example 3 100 parts of the above varnish and 72 mica in a paint shaker
52 parts of silicon carbide ceramic pigment, 15 parts of colorant pigment (Dipyroxide Color Black #9510), 2 parts of pigment dispersant (Disparon 6900-IOX) and 15 parts of xylene were added and dispersed for 30 minutes to form a coating composition. I got a B.

Production example 4 100 parts of the above varnish and 72 mica in a paint shaker
Part, colorant pigment (dipyroxide color black #
9510) 65 parts, pigment dispersant (Disparon 690)
0-10X) and 15 parts of xylene, and
Coating composition C was obtained by dispersing for minutes.

Production Example 5 100 parts of the above varnish and 72 mica in a paint shaker
1 part, 65 parts of a fired ceramic pigment (Dipyroxide Color Green #9310), 2 parts of a pigment dispersant (Disparon 6900-10X) and 15 parts of xylene were added and dispersed for 30 minutes to obtain a coating composition.

Production Example 6 100 parts of the above varnish and 40 parts of mica in a paint shaker
part, titanium white 20 parts, pigment sedimentation prevention agent (Erosil #38
0) and 15 parts of xylene were added and dispersed for 30 minutes to obtain coating composition E.

Production Example 7 100 parts of the above varnish and 40 parts of mica in a paint shaker
part, red iron oxide 20 parts, pigment sedimentation prevention agent (Erosil 938
0) and 15 parts of xylene were added and dispersed for 30 minutes to obtain coating composition F.

Examples 1-5 Coating compositions A, B, and D were diluted with xylene to a 1lh4 photocup of 20-22 seconds and coated on a metal substrate (polished stainless steel plate) to a dry film thickness of 30-22 seconds. 50
The first coating layer A was spray coated so as to have a thickness of μ and dried by heating at 180° C. for 30 minutes.

I got B and D.

On top of the coating layers A, B, D thus obtained, coating compositions E and F are applied.

The second coating layers E and F were formed by coating and heating and drying in the same manner as B and D.

The performance of the infrared absorber thus obtained is shown in Table 1 and FIGS. 1 to 5.

Comparative Examples 1 to 7 Coating compositions A, B, C, D, E, and F were diluted with xylene to a four-ford cup size of 20 to 22 seconds and applied to a metal substrate (polished stainless steel plate). Spray coat to a dry film thickness of 30 to 50μ,
Heat and dry at 0°C for 30 minutes to form the first coating layers A, B,
C, D, E, and F were obtained (Comparative Examples 1 to 6).

Further, on the thus obtained first coating layer C, a second coating layer E was provided by coating the coating composition E in exactly the same manner and heating and drying it (Comparative Example 7).

The performance of the coating layer thus obtained is shown in Table 2 and FIGS. 6 to 12.

[Brief explanation of the drawing]

1 to 5 show the infrared absorption ability of the infrared absorbers obtained in Examples 1 to 5 of the present invention, respectively, with wavelengths of 2.5 μm to 25 μm (wave numbers of 4000 to 4
00 cm-'), and FIGS. 6 to 12 show the infrared absorption ability of the coating layers obtained in Comparative Examples 1 to 7, respectively, at a wavelength of 2.5.
This is a spectral reflectance curve diagram in the region of μm to 25 μm (wave number 4000 to 400 cm). In Figures 1 to 12, the vertical axis is the infrared spectral reflectance (%
), the lower part of the horizontal axis represents the wave number (am-'), and the upper part of the horizontal axis represents the wavelength (μm). Patent Applicant Kansai Paint Co., Ltd. Wave Long Wave Long Wave Figure 2 Wave Length Figure 3 Figure 4 Wave Long Wave Number Figure 5 Wave Long Wave Number Figure 6 Wave Number Figure 7 Wave Long Wave Number Figure 8 Wave Long Wave Number Wave Length f410 Figure wavelength

Claims (1)

[Scope of Claims] (I) An organosilicon compound and/or its low condensate represented by the following general formula [A], and ▲numerical formulas, chemical formulas, tables, etc.▼ (where R is 1 carbon number
~8 hydrocarbon group)... [A] Organosilicon compound and/or its low condensate represented by the following general formula [B] ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼ (However, R' has 1 to 1 carbon atoms) 12 hydrocarbon groups, R is the same as above)... [B] is hydrolyzed in the presence of an acid catalyst, and then the pH is adjusted to 7 or higher using an alkaline substance and condensed to form a silanol at the end of the molecule. 100 parts by weight of a group-free organosilicon high condensate, (II) 30 to 300 parts by weight of at least one extender pigment selected from mica, talc, calcium carbonate, clay, halide, and bentonite, and (III) fired ceramic pigment. On top of the first coating layer formed from a coating composition comprising 30 to 300 parts by weight, (IV) 100 parts by weight of the organic silicon high condensate (I) (V
) An infrared absorber comprising a second coating layer formed of a coating composition comprising 30 to 300 parts by weight of the extender pigment (II) and 10 to 200 parts by weight of the inorganic coloring pigment (VI).