JPS584941B2 - Baked-on soundproofing paint - Google Patents

Description

[Detailed description of the invention] The present invention relates to a novel baking-type soundproofing paint.

More specifically, styrene-butadiene rubber, rosin,
Using at least one type of color vehicle selected from rosin derivatives and petroleum resins as a color vehicle, it has excellent soundproofing properties, impact resistance, rust prevention, chipping resistance, etc., and does not sag on vertical or back surfaces when baked. Regarding paint.

In general, unlike other types of pollution, noise does not directly cause serious damage or harm to the human body.

However, since it causes insomnia, neurosis, etc., prevention measures have recently been attracting particular attention.

For example, soundproofing paints have been applied to noise sources such as vehicles, elevators, and refrigeration equipment.

Conventionally, soundproofing paints for such materials have been widely used, which include bituminous materials such as coal tar and asphalt, and fibrous materials such as asbestos.

However, there is a problem that bituminous materials, asbestos, etc. used in this type of paint are carcinogenic, and an improvement in this problem has been desired.

Therefore, in order to solve the above-mentioned problems, various soundproofing paints using materials other than bituminous materials, such as synthetic resins, as a color vehicle have been proposed.

For example, soundproofing paints containing synthetic resin or synthetic rubber (Japanese Unexamined Patent Publication No. 52-51428) are known, but these are generally extremely poor in impact resistance, adhesion, etc. In particular, synthetic rubbers such as nitrile rubber, polybutadiene rubber, Products using depolymerized rubber have poor adhesion and are therefore almost impractical for use in vehicles such as automobiles, which require very harsh conditions.

On the other hand, for the purpose of improving the corrosion resistance or adhesion of general paint coatings, chemical conversion treatment using a phosphate treatment liquid is usually performed as a pretreatment step for metal coating.

However, in the industrial chemical conversion process, materials to be treated such as iron are immersed in a phosphate treatment tank, but during the treatment process, so-called sludge is produced as a by-product in the treatment tank. and it tended to settle in the tank over time.

However, the disposal of such phosphate sludge is a major problem from a pollution standpoint and is subject to regulations, and its disposal therefore requires a large amount of expense.

Furthermore, with regard to zinc, iron, phosphoric acid, etc. contained in phosphate sludge, mere disposal poses a serious problem from the viewpoint of resource reuse.

Conventionally, many attempts have been made to effectively reuse industrial waste.

For example, a paint composition with anti-corrosion and sound-proofing effects (
JP-A No. 51-143029), paint compositions with anti-rust and sound-proofing effects consisting of waste paint recovered from paint wastewater, bituminous matter, and fibers (JP-A No. 52-26531), or industrial waste. Soundproofing paint (mainly made of iron powder, iron oxide, and ferrite) and synthetic rubber or synthetic resin (
JP-A-52-51428) and the like are already known.

However, the above-mentioned known soundproofing paints are significantly inferior in long-term rust prevention and impact resistance, and therefore cannot be effectively used as soundproofing materials for automobiles and the like under severe conditions.

As described above, no soundproofing paint has yet been obtained that has excellent performance in terms of adhesion and impact resistance against severe vibrations and shocks (particularly shocks at low temperatures).

On the other hand, soundproofing paints are often forced to dry to form a coating, and the temperature in this case varies considerably depending on line conditions, but is generally 80°C to 150°C.

During heating and drying, the viscosity of the paint film decreases temporarily due to the heating, and as a result, a wet paint film with a thickness of 3 to 5 mm may cause defects such as sagging on vertical surfaces or back surfaces. there were.

As a solution to these problems, attempts have been made to improve the sag during baking by increasing the viscosity of the paint by adding thickeners and reducing the amount of solvent. If the coating temperature is increased, paint sprayability becomes difficult, and therefore this method has its limitations.

As described above, no soundproofing paint has been obtained that improves the back and vertical sagging of thick films during baking.

In view of the current situation as described above, the present invention not only has soundproofing properties, but also
The objective is to provide a baking-type soundproofing paint that has even better performance in terms of impact resistance, adhesion, rust prevention, and chipping resistance, and at the same time does not sag vertically or on the back surface during baking. be.

That is, the present invention comprises (a) 30 to 90% by weight of solvent-soluble styrene-butadiene rubber obtained by a solution polymerization method, and at least one type selected from the group consisting of rosin rosin derivatives and petroleum resins.
Color vehicle consisting of 0 to 70% by weight: 100 parts by weight, (0) Filler: 10 to 500 parts by weight,
(c) Sludge whose main components are zinc phosphate, iron phosphate, and free phosphoric acid recovered from the phosphate treatment solution...
...20 to 200 parts by weight, (d) vulcanizing agent...
...Relates to a baking-type soundproofing paint consisting of 0.5 to 10 parts by weight.

The styrene-butadiene rubber used in the present invention is generally commercially available styrene-butadiene rubber obtained by a solution polymerization method and soluble in a solvent.

In particular, stereostyrene butadiene rubber produced by solution polymerization is preferred.

The stereostyrene-butadiene rubber includes a random copolymer or block copolymer of styrene and butadiene. Also, the rosin used in the present invention includes wood rosin, gum rosin, tall oil rosin, etc., and the rosin derivative includes maleic rosin. Examples include rosin esters modified with acids, phenols, etc.

Furthermore, the petroleum resins used in the present invention include synthetic polyterpene resins, aromatic hydrocarbon resins, aliphatic hydrocarbon resins, and aliphatic cyclic hydrocarbon resins.

Each component of the rosin, rosin derivative, and petroleum resin can be used singly or as a mixture of two or more.

The soundproofing paint of the present invention comprises a solvent-soluble styrene-butadiene rubber obtained by the solution polymerization method as described above, rosin,
The main color vehicle is at least one selected from the group consisting of rosin derivatives and petroleum resins.

Their mixing ratio is styrene butadiene rubber 30 to 9
0% by weight, preferably 40-80% by weight, and 10-70% by weight, preferably 20-60% by weight of at least one selected from the group consisting of rosin, rosin derivatives, and petroleum resins.

Furthermore, in another aspect of the present invention, the color vehicle 100
The soundproofing paint includes 5 to 40 parts by weight, preferably 7 to 35 parts by weight of epoxy ester resin.

By doing so, the solvent resistance of the coating film can be improved.

Examples of the epoxy ester resin include those obtained by esterifying a bisphenol type epoxy resin having an epoxy equivalent of about 300 to 2,500 with an aliphatic such as dehydrated castor oil, linseed oil, soybean oil, white flower oil, and tall oil.

The epoxy ester resins also include those modified with acrylic or urethane by conventional methods.

The mixing ratio of each of the above components is determined in relation to the purpose of the present invention.

For example, if the amount of styrene-butadiene rubber mixed is less than the above range, impact resistance, soundproofing properties, etc. will decrease.

Further, the purpose of adding rosin and/or rosin derivatives is to improve the adhesion of the coating film, but if the amount added exceeds the above-mentioned amount, the elasticity of the coating film decreases and the impact resistance deteriorates.

Furthermore, petroleum resins are mixed and used within the above range in order to improve the water resistance, adhesion, alkali resistance, chipping resistance, etc. of the coating film.

Furthermore, epoxy ester resins are mixed and used within the above range in order to improve the solvent resistance, adhesion, etc. of the coating film.

In addition, when the rosin and/or rosin derivative and petroleum resin are mixed and used, the petroleum resin in the mixture is 80% by weight or less, particularly 50 to 75% by weight (the weight of the rosin and/or rosin derivative and petroleum resin). Ratio 1:1~
It is preferable to adjust to 3).

On the other hand, examples of fillers used in the present invention include plastic fibers, glass fibers, wollastonite, diatomaceous earth, wood flour, rice hull powder, cork powder, micro balloons, shirasu balloons, resin powders, mica-like iron oxide, etc. , tire powder, cotton powder, natural calcium silicate powder, asbestos powder, fibrous single crystal of insoluble anhydrite, etc.

These may be used alone or as a mixture of two or more.

In particular, it is preferable to use fibrous single crystals of insoluble anhydrite because they are less irritating to the skin and are therefore superior in the production and application work of paints.

The fibrous single crystal (■-CaS04) is an α-type gypsum (α-CaS04) produced by a hydrothermal reaction using gypsum as a raw material.
It can be obtained by heating and stabilizing S04.TH20).

The fibrous single crystal has a diameter dO. 1~30μ, length 1
10 to 5000μ, l/d is preferably 20 to 200, particularly d is 0.5 to 6μ, l is 30 to 400μ, l/d is preferably
Those with d of 30 to 90 are preferred.

The filler is 10 to 500 parts by weight, preferably 30 to 400 parts by weight, based on 100 parts by weight (nonvolatile content) of the color vehicle.
Used in parts by weight.

If the amount of the filler is less than 10 parts by weight in the above ratio, the soundproofing effect will not be so good, the coating will tend to crack, and the coating will tend to blister during heating and drying.

Moreover, if more than 500 parts by weight is added, the rust prevention properties, impact resistance, film formability, chipping resistance, etc. of the coating film will be deteriorated, which is not preferable.

Furthermore, the sludge recovered from the phosphate treatment solution used in the present invention (abbreviated as phosphate sludge) is generated during the phosphate treatment process, and the sludge is generated during the phosphate treatment process. It is obtained by processing.

The main components of the phosphate sludge are zinc phosphate, iron phosphate, and free phosphoric acid.

In particular, those having a water-soluble content of 10% by weight or less are preferred.

The phosphate sludge may contain almost no water when dried.

In the present invention, the phosphate sludge has a color vehicle of 100%
20 to 200 parts by weight, preferably 40 to 200 parts by weight
It is used in a proportion (solid content ratio) of 150 parts by weight.

If the lunate sludge is less than 20 parts by weight in the above ratio, the rust prevention properties of the coating film will be significantly reduced, which is not preferable.

Moreover, if it exceeds 200 parts by weight, the stability of the coating material will be impaired, which is not preferable.

In particular, in the present invention, 100 parts by weight of the phosphate sludge, 5 to 150 parts by weight of the alkaline compound (modifier),
Very favorable results can be obtained using a modified phosphate sludge containing 30 to 300 parts by weight of water.

The modified phosphate sludge is made of phosphate sludge, a predetermined amount of modifier, and water (if the phosphate sludge contains water in advance, the total water content is 30 to 300%).
It is obtained by drying a slurry-like phosphate sludge obtained by adding (parts by weight) and mixing and stirring.

Examples of the modifier (alkaline compound) include carbonate lime powder, precipitated calcium carbonate, slaked lime, quicklime, magnesium carbonate, potassium silicate, sodium silicate, soda carbonate, caustic soda, caustic potash, and dolomite. , these may be used alone or as a mixture of two or more.

Particularly preferred are lime carbonate powder and/or precipitated calcium carbonate.

When the modified phosphate sludge is used, the amount used is 20 to 200 parts by weight per 100 parts by weight of the coloring agent as the phosphate sludge excluding modifiers and the like.

By using the modified phosphate sludge thus obtained, the free acid in the phosphate sludge is neutralized, and the rust prevention of the paint film and the stability in the paint are further improved.
Soundproofing properties are also improved to some extent.

Further, as the vulcanizing agent used in the present invention, sulfur or an organic peroxide having a decomposition temperature (half-life of 1 minute) of 100 to 170°C, such as 1,1-bis(t-butylperoxy)
3,3.5-1-limethylcyclohexane, n-butyl 4,4-bis(1-butylperoxy)valerate, ■
, 1-di(t-butylperoxy)cyclo, xane, cabrylide peroxide, lauroyl peroxide, penzoyl peroxide, t-butylperoxyiso-propyl carbonate, and the like.

The vulcanizing agent is used in an amount of 0.5 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight (nonvolatile content) of the color vehicle.

If the amount of the vulcanizing agent is less than 0.5 parts by weight, there is no effect of preventing dripping, and if it exceeds IO parts by weight, the film becomes hard and the impact resistance and chipping resistance are reduced, so it is preferable. do not have.

In the present invention, when sulfur is used as a vulcanizing agent, it is 20 to 150% by weight, preferably 50% by weight based on the vulcanizing agent.
~130% by weight of vulcanization accelerator is used.

As the vulcanization accelerator, all those commonly used in combination with sulfur can be used.

For example, diphenylguanidine, 2-mercaptobenzothiazole, dibenzothiazyl disulfide, 2-(4
Organic accelerators such as monomorpholinodithio)benzothiazole N-cyclohexyl-2-benzothiazylsulfenamide, tetramethylthiuram monosulfate, tetramethylthiuram disulfide, or zinc white, zinc carbonate, oxidized Examples include inorganic accelerators such as magnesium, and fatty acids such as stearic acid, oleic acid, lauric acid, and zinc stearate, or derivatives thereof.

These may be used alone or as a mixture of two or more.

If necessary, ordinary coloring pigments, extender pigments, other synthetic resins, solvents, additives, etc. can be added to the baking-type soundproofing paint of the present invention.

The baking type soundproofing paint of the present invention can be obtained by adding the coloring agent, phosphate sludge, vulcanizing agent, filler, and, if necessary, the solvent, etc., and stirring and mixing.

The soundproofing paint of the present invention thus obtained is applied onto the object by a conventional method such as brushing, spraying, dipping, or roller painting, and is baked at 80 to 150°C to form a film. It is said that

In the present invention, styrene-butadiene rubber and at least one selected from the group consisting of rosin, rosin derivatives, and petroleum resins are combined as a color vehicle, phosphate sludge, filler, vulcanizing agent, and, if necessary, epoxy ester resin. Excellent soundproofing, impact resistance, and
It has adhesion, chipping resistance, water resistance, alkali resistance, rust prevention, etc., and can produce a coating film that does not sag on vertical surfaces or back surfaces when baked, so it can be used, for example, as soundproofing paint on the bottom of cars, and in kitchens. It can be used for a wide range of purposes, both domestic and industrial, such as the back of stainless steel sinks, the attics of buildings, the back of wall materials, curtain walls, elevators, refrigeration equipment, general vehicles, etc.

The details of the present invention will be explained below with reference to Examples.

"Part" or "%" represents "part by weight" or "% by weight", respectively.

Example 1 50 parts of styrene-butadiene rubber produced by solution polymerization method [manufactured by Asahi Kasei Kogyo ■, trade name: 30% non-volatile solution of Tufprene A dissolved in xylol: styrene/butadiene = 4-6, blocks with a molecular weight of 70,000 to 100,000 Copolymer] Maleated rosin 5 [Non-volatile content 75% solution obtained by dissolving Harimatsu R-80 (trade name, manufactured by Harima Kasei ■ in xylol)] Synthetic polyterbene resin 10 [Non-volatile content 70% solution obtained by dissolving Quinton 1500 (trade name manufactured by Nippon Zeon ■) in xylol] Solution] Phosphate sludge 18.5 Plastic fiber 15 [Contains 70 or more nylon fibers with a diameter of 3 to 10 μm and a length of 100 to 300 μm] Vulcanizing agent [Product name: Perhexa 3M manufactured by NOF Corporation) 1. 5100 The above composition was stirred and mixed using a disper to obtain a soundproofing paint of the present invention.

The paint was applied by airless spray painting on a mild steel plate, and as a back sag removal test, immediately after painting, the paint was set with the surface facing down for 20 minutes, and then forced drying was performed at 150°C for 20 minutes to remove any sagging. For other tests that looked at the properties, test pieces were prepared in the same way, and after drying,
The test was conducted after being left at room temperature for 24 hours.

The same procedure was carried out for the following Examples and Comparative Examples.

Example 2 Styrene-butadiene rubber (same as Example 1) 40 parts Rosin ester 1o [75% solution of Ester Gum H manufactured by Arakawa Forestry Chemical Co., Ltd., dissolved in xylol] Aliphatic cyclic hydrocarbon resin 15 [Arakawa Forestry Chemical Co., Ltd.] ■ 70% non-volatile solution of Alcon P-85 dissolved in xylol] Modified phosphate sludge 18 Natural calcium silicate powder 15 [Product name Wollastonite F-1, manufactured by Interspace Co., Ltd.] Nono-oxide 2 [Japan Product name Perbutyl I manufactured by Oil & Fat 1] 100 The above composition was stirred and mixed and applied in the same manner as in Example 1.
It was subjected to a comparative test.

Incidentally, the modified phosphate sludge is phosphate sludge 10
Example 3 Using a slurry obtained by mixing 0 parts of precipitated calcium carbonate with 60 parts of precipitated calcium carbonate and 100 parts of water, 40 parts of styrene-butadiene rubber produced by solution polymerization method [trade name Solprene 411, manufactured by Asahi Kasei Kogyo Corporation] was mixed with xylol. 30% solution dissolved in: styrene/butadiene-3/7, block copolymer with a molecular weight of 240,000 to 250,000] Maleated rosin (same as in Example 1) 10 Epoxy ester resin 10 [Product name: Betucosol P786, manufactured by Nippon Reichhold Co., Ltd.] , using dehydrated castor oil, non-volatile content 50%] Fibrous single crystal of insoluble anhydrite 18 [Product name: ONODA-GF manufactured by Onoda Cement ■: t = 3 0-120μ, d
= 0. 5-1.5μ, 7/d=30-90] Phosphate sludge 2o sulfur powder 1 [Reagent special grade manufactured by Wako Pure Chemical Industries Ltd.] Vulcanization accelerator 1 [Product name Accel CZ, 1 manufactured by Kawaguchi Chemical ■ 100 Above The composition was stirred and mixed, and applied in the same manner as in Example 1 for a comparative test.

Example 4 Styrene-butadiene rubber (same as Example 1) 50 parts Maleated rosin (same as Example 1) 5 Aliphatic cyclic hydrocarbon resin (same as Example 2 → 6 Fibrous single crystal of insoluble anhydrite 10 parts (7=150-400μ, d=
2 to 6μ, t/d=30 to 80] Modified phosphate sulfur powder 28 Sulfur powder (same as Example 3) 0.5 Vulcanization accelerator 0.5 [Product name: Accel DS manufactured by Kawaguchi Kagaku ■] 100 Above composition The mixture was stirred and mixed using a disper, and applied in the same manner as in Example 1 for a comparative test.

The modified phosphate sludge is phosphate sludge 1.
00 parts, 20 parts of carbonate lime powder, and 40 parts of water were mixed and kneaded.

Example 5 Styrene-butadiene rubber (same as Example 1) 40 parts Synthetic polyterbene resin 20 (same as Example 1) Fibrous single crystal of insoluble anhydrite 24.8 [t=
30 to 150 μ, d = 1 to 2 μ, t/d = 20 to 80] Phosphate sludge 15 Peroxide 0.2 [Product name: Nyper B manufactured by NOF ■] 100 The above composition was stirred and mixed with a disper and carried out. It was applied in the same manner as in Example 1 and subjected to a comparative test.

Example 6 Styrene butadiene rubber (same as Example 3 → 5 o parts rosin ester (same as Example 2) 5 Aromatic hydrocarbon resin 12 [50% non-volatile solution of Esso Chemical Co., Ltd. Meiko Skorets 3102 dissolved in xylol) ] Modified phosphate sludge (same as Example 2) 15 wollastonite
15 Sulfur powder (same as Example 4) 1.5 Vulcanization accelerator A1.0 [Product name: Accel DM manufactured by Kawaguchi Kagaku ■] Vulcanization accelerator B O. 5 [Product name: Accel D, manufactured by Kawaguchi Kagaku ■] 100 The above composition was stirred and mixed with a disper, and applied in the same manner as in Example 1 for a comparative test.

Example 7 Styrene-butadiene rubber (same as Example 1) 50 gummy gum rosin (produced in China, softening point 70-75°C, acid value 165 or more, xylol solution with non-volatile content 75%) 15 Phosphate sludge 18.5 Plastic fiber ( Same as Example 1) 15 Vulcanizing agent (Example 1)
) 1.5 100 The above composition was stirred and mixed with a disper to obtain the soundproofing paint of the present invention.

Example applied in the same manner as Example 1 and subjected to a comparative test
8 Styrene butadiene rubber (same as Example 1) 40 Necrotic gum rosin (same as Example 7) 10 Synthetic polyterpene resin (same as Example 1) 15 Modified phosphate sludge (same as Example 2) 18 Natural calcium silicate Powder (same as Example 2) 15 Peroxide (same as Example 2) 2100 The above composition was stirred and mixed and applied in the same manner as Example 1.
It was subjected to a comparative test.

Example 9 Styrene butadiene rubber (same as Example 3) 40 Necrotic gum rosin (same as Example 7) 5 Synthetic polyterpene resin (same as Example 1) 5 Epoxy ester resin (same as Example 3) 10 Insoluble anhydrite Fibrous single crystal 18 (same as Example 3) Phosphate sludge 20 Sulfur powder (same as Example 3) Vulcanization accelerator (same as Example 3) 1100 The above compositions were stirred and mixed, and Example It was applied in the same manner as in Example 1 and subjected to a comparative test.

Comparative Example 1 Styrene-butadiene rubber (same as Example 1) 60 parts Asbestos powder 10 Talc
30100 The above composition was stirred and mixed using a disper, and applied in the same manner as in Example 1 for a comparative test.

Comparative Example 2 Asphalt (60% xylene solution) 50 parts Talc 20 Asbestos powder 30100 The above composition was stirred and mixed with a disper, and applied in the same manner as in Example 1 for a comparative test.

Comparative Example 3 Styrene-butadiene rubber (same as Example 1) 50 parts Maleated rosin (same as Example 1) 10 Synthetic polyterpene resin (same as Example 1) 15 Talc
5 plastic fiber
19.8 Sulfur powder (same as Example 3) 0.1 Vulcanization accelerator (same as Example 4) 0.1 100 The above composition was stirred and mixed with a disper and applied in the same manner as Example 1 for comparison. Tested.

Comparative Example 4 Styrene-butadiene rubber (same as Example 3) 50 parts Rosin ester (same as Example 2) 10 Aromatic hydrocarbon monoresin (same as Example 6) 20 Talc
15 Wollastonite 10 Sulfur powder (same as Example 3) 4 Vulcanization accelerator (Example 3)
1100 The above composition was stirred and mixed using a disper, and applied in the same manner as in Example 1 for a comparative test.

As is clear from the comparative test results table, the baked-on soundproofing paint of the present invention not only has superior soundproofing properties compared to conventional soundproofing paints, but also has excellent adhesion, chipping resistance, impact resistance, It is clear that it is significantly superior in terms of both rust prevention and dripping resistance.

Claims (1)

[Scope of Claims] 1 (a) 30 to 90% by weight of a solvent-soluble styrene-butadiene rubber obtained by a solution polymerization method and at least 10 to 90% of at least one kind selected from the group consisting of rosin, rosin derivatives, and petroleum resins. Color vehicle consisting of 70% by weight...
...100 parts by weight, (mouth) filler...1
0 to 500 parts by weight, h) Sludge whose main components are zinc phosphate, iron phosphate, and free phosphoric acid recovered from the phosphate treatment solution...20 to 200 parts by weight, ( d) Vulcanizing agent: Baking type soundproofing paint consisting of 0.5 to 10 parts by weight. 2. The baking type soundproofing paint according to claim 1, wherein the vulcanizing agent is sulfur or an organic peroxide. 3. The baking type soundproofing paint according to claim 1, wherein the filler is a fibrous single crystal of insoluble anhydrite. 4. Claim 1, wherein the sludge mainly composed of zinc phosphate, iron phosphate, and free phosphoric acid recovered from the phosphate treatment solution contains 10% by weight or less of water-soluble matter. Baked-on soundproofing paint as described. 5. Claim 1, wherein the sludge containing zinc phosphate, iron phosphate, and free phosphoric acid as main components recovered from the phosphate treatment solution is a modified phosphate sludge modified with an alkaline substance. Baked-on soundproofing paint as described. 6. The baking type soundproofing paint according to claim 1, wherein the filler is lime carbonate powder and/or precipitated calcium carbonate. 1 (a) Consisting of 30-90% by weight of solvent-soluble styrene-butadiene rubber obtained by solution polymerization and 10-70% by weight of at least one species selected from the group consisting of rosin, rosin derivatives and petroleum resins. Color vehicle...
...100 parts by weight, (b) filler...1
0 to 500 parts by weight, (c) Sludge whose main components are zinc phosphate, iron phosphate, and free phosphoric acid recovered from the phosphate treatment solution...20 to 200 parts by weight, (d) A vulcanizing agent: 0.5 to 10 parts by weight; (e) An epoxy ester resin: 5 to 40 parts by weight. 8. The baking type soundproofing paint according to claim 7, wherein the vulcanizing agent is sulfur or an organic peroxide. 9. The baking type soundproofing paint according to claim 7, wherein the filler is a fibrous single crystal of insoluble anhydrite. 10. Claim 1, wherein the sludge mainly composed of zinc phosphate, iron phosphate, and free phosphoric acid recovered from the phosphate treatment solution contains 10% by weight or less of water-soluble matter. Baked-on soundproofing paint as described. 11 Zinc phosphate recovered from the phosphate treatment solution,
The baking type soundproofing paint according to claim T, wherein the sludge containing iron phosphate and free phosphoric acid as main components is a modified phosphate sludge modified with an alkaline substance. 12. The baking type soundproofing paint according to claim γ, wherein the filler is lime carbonate powder and/or precipitated calcium carbonate.