JPH0116273B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a composition that is applied to a vehicle to protect the vehicle from scratches caused by gravel, rock salt, and the like. As a protective composition for the purpose of rust prevention, soundproofing, etc. on the underside of the vehicle body floor or wheel house, etc.
Conventionally, compositions containing bituminous materials such as coal tar and asphalt, modifiers for bituminous materials, fillers such as fibrous fillers such as asbestos, powdery fillers, and organic solvents have been used. However, there is a problem that the bitumen and asbestos used in this type of paint are carcinogenic.
Improvements have been requested. On the other hand, there is a strong desire to improve the durability of vehicles, especially automobiles, and in North America and Northern Europe, large amounts of rock salt are sprayed on roads during the winter.
Scratches caused by rock salt, gravel, and flying stones thrown in by cars running at high speed, and the occurrence of rust on the scratched parts, have become a major problem. Therefore, it has been desired to develop a composition for the underside of a car body and a wheel house that has excellent chipping resistance against rock salt, gravel, and flying stones, especially chipping resistance in a low temperature range, adhesion, and bending workability. However, conventional bituminous protective compositions have poor chipping resistance at room temperature, so protective compositions with excellent chipping resistance have been developed, such as spraying agents based on vinyl chloride sol-type resins and spraying agents based on synthetic rubber latex. etc. are already provided. However, vinyl chloride sol-type spraying agents and synthetic rubber latex-based spraying agents are not effective in terms of chipping resistance unless the coating film is applied at a thickness of 600μ to 700μ or more. The flexibility and bending processability were insufficient, and improvements were desired. As a means to solve these problems, spraying agents using nitrile rubber, polybutadiene rubber, petroleum resin, etc. as protective compositions have been proposed as in JP-A-52-51418 and JP-A-55-34219. However, even when these resins are used, a thickness of 700μ to 1000μ is required to have sufficient chipping resistance, cold adhesion resistance, and rust prevention.
A certain amount of coating film thickness was required. On the other hand, from the standpoint of energy conservation, there is a strong desire to reduce the weight of vehicles, and in the field of vehicle painting, it is desired to make the film as thin as possible. The same is true. In view of the current situation, the inventors of the present invention have conducted extensive research and found that a coating film thickness of 500 μm or less can be used as a protective composition for the underfloor and wheelhouse areas of vehicles, and has excellent chipping resistance, rust prevention, adhesion, and We have now invented a vehicle protection composition that has excellent adhesion at low temperatures, bending processability, and chipping resistance. This product improves the problems associated with the protective compositions used in the underfloor and wheelhouse areas of conventional vehicles, and allows for thinner coatings than before in order to meet the needs of the times in terms of energy conservation. With protective compositions,
This is a new technology that has never existed before. In other words, the present invention comprises (a) a polyol resin (A) having a hydroxyl group value of 30 to 300, and (b) an effective isocyanate group content of 1 to 15% by weight.
It consists of a blocked isocyanate-containing resin (B), (c) a dissociation catalyst for blocked isocyanate (C), and (d) calcium oxide, and (e) the compounding ratio of effective isocyanate groups to hydroxyl groups is equivalent to (A). ):(B)=50:100
~100:50, (f) The amount of catalyst (C) is 0.01 to 5% by weight and the amount of calcium oxide is 1% by weight based on the total amount (solid content) of resin (A) and resin (B). -10% by weight of a vehicle protection composition. Furthermore, the composition of the present invention is applied to the underside of the vehicle floor, the wheel house area, and the lower part of the periphery at a rate of 50μ or more.
If a coating film is formed in the range of 500μ or less, it can become a practically useful protective film. In the present invention, in particular, since calcium oxide is included, it forms a urethane bond with the isocyanate group, making the coating stronger (higher hardness) and contributing to improving chipping resistance. This reaction formula is it is conceivable that. The blending ratio of this calcium oxide is preferably 3 to 7% by weight based on the total amount (solid content) of the resin (A) and resin (B). The hydroxyl value in the present invention refers to the number of milligrams of potassium hydroxide equivalent to neutralizing 1 g of polyol resin. Furthermore, polyol resin (A)
refers to resins with hydroxyl groups with a hydroxyl value of 30 or more and 300 or less, such as polyester polyols, polyether polyols, epoxy polyols, acrylic polyols, alkyd resins,
These include oils and fats, and even if one of these is used alone, two
It can be used in combination with more than one species. Among these, polyester polyols and polyether polyols are most preferred. The reason for this is that the required performance of the protective composition of the present invention is as follows:
It is preferable that the non-volatile content during coating be as high as possible. This type of composition has chipping resistance,
Chipping resistance after water resistance deterioration, cold bending resistance,
Adhesion, impact resistance, etc. are required, and epoxy polyols tend to have poor cold resistance and bending properties due to their characteristics, acrylic polyols have a low nonvolatile content during painting and tend to have poor chipping resistance, and alkyd resins, Oils and fats tend to have somewhat poor chipping resistance after water resistance deteriorates. The polyester polyol referred to in the present invention is produced by heating and condensing a polyhydric carboxylic acid and a polyhydric alcohol at a temperature of 150°C to 250°C in an equivalent proportion of hydroxyl groups to carboxyl groups. refers to the resin obtained by Polycarboxylic acids are compounds having at least one carboxyl group in one molecule, including aromatic polycarboxylic acids, saturated or unsaturated aliphatic polycarboxylic acids, and alicyclic polycarboxylic acids. etc., and any of them can be used. As the aromatic polycarboxylic acid, for example, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, etc. can be used. Examples of saturated or unsaturated aliphatic polycarboxylic acids include succinic acid,
Examples include azelaic acid, adipic acid, pimelic acid, sebacic acid, maleic acid, and fumaric acid. Examples of saturated or unsaturated alicyclic polycarboxylic acids include hexahydrophthalic acid, methylhexahydrophthalic anhydride, tetrahydrophthalic anhydride,
Methyltetrahydrophthalic anhydride and the like can be preferably used. Further, oxycarboxylic acids having one or more carboxyl groups in one molecule and at least one or more hydroxyl groups in the same molecule can also be used as the polyvalent carboxylic acid. Examples of oxycarboxylic acids include hydroxybenzoic acid, hydroxystearic acid, and tartaric acid. Polyhydric alcohols are compounds having at least two or more hydroxyl groups in one molecule,
For example, ethylene glycol, propylene glycol, butanediol, neopentyl glycol,
Examples include trimethylpentanediol, diethylene glycol, dipropylene glycol, hydrogenated bisphenol A, glycerin, trimethylolethane, trimethylolpropane, pentaesritol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, and the like. The polyether polyol referred to in the present invention is, for example, polyoxyethylene glycol, polyoxypropylene glycol, polyoxybutylene glycol, polyoxypropylene triol, polyoxypropylene quadrol, or a block or randomly copolymerized polyether of ethylene and propylene. Examples thereof include polyols and polymer polyols obtained by partially grafting acrylic onto these polyols. The hydroxyl value of the polyol resin (A) of the present invention is
It is 30 or more and 300 or less, more preferably 50 or more and 200 or less. When the hydroxyl value is lower than 30, the amount of hydroxyl groups that react with the effective isocyanate is small, so the crosslinking density is insufficient, resulting in poor chipping resistance, chipping resistance after water resistance deterioration, adhesion, etc. When the hydroxyl number is more than 300, the cured coating film has poor impact resistance and cold bending processability, so it cannot be used as a protective coating composition. The polyol resin (A) referred to in the present invention preferably has a number average molecular weight usually in the range of about 1,000 to 20,000, with those in the range of 1,500 to 10,000 being particularly optimal. Next, effective isocyanate group content % in the present invention
The blocked isocyanate-containing resin (B) whose content is 1% by weight or more and 15% by weight or less is, for example, tolylene diisocyanate, metaphenylene diisocyanate, naphthylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate. , dicyclohexylpropane diisocyanate, trimethylpentane diisocyanate, and other aromatic, aliphatic, or alicyclic polyvalent isocyanates, polymers of these polyvalent isocyanates, or adducts of these polyvalent isocyanates and polyhydric alcohols (polymerization of polyvalent isocyanates and polyhydric alcohols). It refers to compounds synthesized by reacting polyvalent isocyanate groups (such as adducts (addition products reacted in excess equivalent amount with respect to a hydrovalent alcohol) with a compound having active hydrogen, and causing the active isocyanate groups to disappear at room temperature. Examples of the polyhydric alcohols include polyester polyols, polyether polyols, acrylic polyols, resins such as epoxy resins, diols such as ethylene glycol, propylene glycol, butanediol, trimethylolpropane, trimethylolethane, glycerin, pentaerythritol, etc. Triol, quadrol, etc. Examples of the above-mentioned compounds having active hydrogen include aliphatic alcohols such as methanol and ethanol, cyclic alcohols such as phenol, benzyl alcohol, and cyclohexanol;
It refers to oximes such as methyl ethyl ketoxime and methyl isobutyl ketoxime, lactams such as α-caprolactam and β-propiolactam, and active methylenes such as diethyl malonate, ethyl acetoacetate, and butyl acetoacetate. These active hydrogen-containing compounds are preferably reacted with the above-mentioned isocyanate in an equivalent ratio of 1.0 to 1.1 in an excess of active hydrogen. Effective isocyanate group content % of (B) in the present invention
is the content weight of isocyanate groups in the above aromatic, aliphatic or alicyclic polyvalent isocyanates, polymers of these polyvalent isocyanates, or adducts of these polyvalent isocyanates and polyhydric alcohols. It is the percentage value calculated by dividing the total weight of the substances plus the weight of the active hydrogen-containing compound with which they were reacted. In the present invention,
The effective isocyanate group content is 1% by weight or more and 15% by weight or less, more preferably 3% by weight or more and 12% by weight or less. When the effective isocyanate group content is lower than 1% by weight, crosslinking is insufficient and chipping resistance is poor and the composition cannot be used as a protective composition. When the effective isocyanate group content is higher than 15% by weight, the cured coating film becomes hard and has poor impact resistance, poor bending workability at low temperatures, and cannot be used as a protective composition. In the present invention, the blocked isocyanate dissociation catalyst (C) refers to commonly used organic or inorganic compounds of various metals such as tin compounds, bismuth compounds, titanium compounds, and tertiary amines. Examples of organic or inorganic compounds of various metals include tin octoate, tin chloride, butyl tin trioxide, dibutyltin diacetate, dibutyltin dilaurylate, bis(2-ethylhexyl)tin oxide, dibutyldibutoxytin, bismuth trichloride,
Examples include bismuth octenoate, tetraxy(2-ethylhexyl)titanate, and tetrabutoxytitanium. Examples of tertiary amine compounds include triethylenediamine, bentamethyldiethylenetriamine, 1,4-diazabicyclo(2,2,
2) Octane, N,N-dimethylcyclohexylamine, N-methyldicyclohexylamine,
N,N,N',N'-tetramethylpropylenediamine, N,N,N',N'-tetramethylhexyldiamine, 1,8-diazabicyclo(5,4,
0) undecene-7 and their phenol salts,
Tertiary amine compounds such as higher fatty acid salts such as oleic acid, octylic acid, and 2-ethylhexanoic acid, morpholine compounds such as N-ethylmorpholine and N-methylmorpholine, N,N-dimethylethanolamine, N,N- Examples include alkanolamine compounds such as diethylethanolamine. In the present invention, among the above metal organic or inorganic compounds, organic or inorganic tin compounds, 1,8-diazabicyclo(5,4,0)undecene-7 or their phenol salts, oleic acid, 2-ethylhexanoic acid , higher fatty acid salts such as octylic acid are particularly preferred, and the above compounds can be used alone or in combination. The amount of the blocked isocyanate dissociation catalyst (C) used in the present invention is 0.01 to 5% by weight based on the total amount (solid content) of the resin (A) and resin (B), but a particularly preferable range is The content is 0.2% by weight or more and 4% by weight or less. When the dissociation catalyst (C) is less than 0.01% by weight, the reaction between isocyanate groups and hydroxyl groups is insufficient, and chipping resistance, chipping resistance after water resistance deterioration, adhesion, etc. tend to deteriorate. When the dissociation catalyst (C) is more than 5% by weight, it cannot be used as a protective composition because it becomes expensive and the storage stability of the protective composition deteriorates. Next, in the present invention, the blending ratio of effective isocyanate groups to hydroxyl groups is expressed as an equivalent ratio.
(A):(B)=50:100 to 100:50, particularly preferably (A):(B)=70:100 to 100:70. In the present invention, when the amount of (A) is less than (A):(B)=50:100, the cured coating film tends to become hard and the bending processability at low temperatures is poor. Moreover, when (A) is more than (A):(B)=100:50, curing and crosslinking is insufficient, resulting in a decrease in chipping resistance and chipping resistance after deterioration of water resistance. In the protective composition of the present invention, the above-mentioned (A), (B) and
In addition to component (C), for example, inorganic pigments such as titanium oxide, carbon black, red iron, oxide yellow, organic pigments such as phthalocyanine blue and phthalocyanine green, clay, calcium carbonate, mica, vermiculite, clay, barite, silica, etc. As additives and diluting solvents such as fillers, leveling improvers, anti-cissing agents, pigment dispersants, anti-sagging agents, etc., organic solvents such as aromatic solvents, aliphatic solvents, ketones, esters, alcohols, etc. The solvent and the like may be blended using a known stirrer such as a disper, and a known dispersing machine such as a ball mill, sand grinder, or roll mill. In addition to the above-mentioned components in the present invention, other cellulose derivatives, petroleum resins, epoxy resins, melamine resins,
Synthetic resins such as urea resin, phenolic resin, synthetic rubber, and rosin, and natural resins can also be used in addition. The vehicle protective composition made of the above-mentioned component composition has extremely stable storage stability, and the coating film formed by applying it to the vehicle body has chipping resistance,
It is a protective composition with excellent chipping resistance after water resistance deterioration, adhesion, impact resistance, cold bending resistance, corrosion resistance, etc. The protective composition of the present invention is most suitable for applying to a vehicle to protect the vehicle from scratches caused by gravel, rock salt, etc. Application sites include the underside of the floor, the inner surface of the wheel house, the wheelhouse panel, the outer sill, the lower parts of the vehicle periphery such as the front and rear aprons, and the suspended fuel tank. The application method is to adjust the viscosity of the protective composition to 100 cps or more.
Airless spray painting and hot airless spray painting with paint adjusted to about 20,000 cps are common, but it can also be used for repairs such as brush painting, roller painting, or spatula painting, and for applying to complex areas without masking. In the case of vehicles, these protective compositions can be used in all processes, such as on the cured electrodeposited undercoating paint, on the cured intermediate coat, and on the cured topcoat. I can do it. Usually, it is mainly used on the underside of the vehicle floor and the wheel well, and therefore it is generally applied on top of the electrodeposited coating. The protective film formed by coating can be baked and hardened at a temperature of about 100°C to 170°C for 10 minutes to 40 minutes. In the present invention, the coating film thickness is 50μ or more and 500μ or less. When the coating film thickness is less than 50μ, the chipping resistance and the chipping resistance after deterioration of water resistance are insufficient and the composition cannot be used as a protective composition. Also, the coating thickness
When it is thicker than 500 μm, the possibility of reducing the weight of the vehicle, which is one of the objects of the present invention, is lost, and furthermore, thick coating of expensive urethane resin poses a cost problem and is difficult to use. Here, the present invention will be explained in more detail with reference to Examples and Comparative Examples. It goes without saying that the present invention is not limited only to the following examples. In Examples and Comparative Examples, parts are parts by weight, and % is weight %. Example 1 190 parts of phthalic anhydride, 384 parts of adipic acid, 60 parts of trimethylolpropane, neopentyl glycol
445 parts, 0.5 part of dibutyltin oxide in a stirrer,
The mixture was placed in a four-necked flask equipped with a thermometer, and dehydration was carried out at a reaction temperature of 180°C to 240°C while passing inert gas, and the reaction was terminated when the acid value reached 1.5.
Dilution was performed with 125 parts of xylol and 125 parts of cellosol acetate to obtain a polyester polyol (A). The resulting resin (A) has a hydroxyl value of 80 (calculated as solid content)
The number average molecular weight is a polystyrene equivalent value determined by gel permeation chromatography.
(The number average molecular weights of the examples described below were also measured in the same manner.) Next, a four-necked flask equipped with a stirrer, a thermometer, and an inert gas inlet tube was charged with polypropylene glycol (PPG-1000, a diol with a number average molecular weight of 1000). )
1000 parts, trimethylolpropane 134 parts, 2,4
870 parts of -80TD1, 429 parts of xylol, and 429 parts of cellosolve acetate were charged, and the reaction was carried out at 60 to 80 °C while introducing an inert gas. When the isocyanate group % reached 10% in terms of solid content, the reaction took place. has been discontinued. (Hereafter, the % hydroxyl value containing isocyanate groups is expressed in terms of solid content.) Next, 1000 parts of this resin was placed in another four-necked flask, and 150 parts of methyl ethyl ketoxime was gradually added dropwise from the dropping funnel to 60°C. The reaction was carried out at 80°C. 80 minutes after completion of dripping
The temperature was raised to .degree. C. and the reaction was carried out for about 1 hour, and then diluted with xylene to a solid content of 60% to obtain a blocked isocyanate resin (B). The effective isocyanate % of this resin (B) was 8.2%. A protective composition was produced using this resin with the following formulation. Polyester polyol (A) 100 parts Blocked isocyanate (B) 97.4 parts Catalyst SA-106 (Note) 2.5 parts Calcium carbonate 208 parts Carbon black 2 parts Calcium oxide 4 parts Mixing ratio of hydroxyl groups and isocyanate groups
100:100 (Note) 1,8-diazerbicyclo(5,4,0) undecene-7 oleate, Sanabbot Co., Ltd.
Product: The protective composition thus produced has a weight ratio of xylol and cyclohexanone of 1:1.
With a B-type viscometer using the thinner
Dilution was performed until the temperature reached 4500 cps/20°C. Next, apply an epoxy cationic electrodeposition paint,
A dry coating film of the above protective composition is applied using an airless coating machine onto a steel plate on which an undercoat coating film has been formed by baking hardening.
Painted to a thickness of 350μ and heated in an atmosphere of 140℃ for 20 minutes.
Bake hardening was performed for minutes. The performance test results of this coating film showed very good results as shown in Table 2. Example 2 633 parts of adipic acid, 109 parts of trimethylolpropane
206 parts of neopentyl glycol, 210 parts of diethylene glycol, and 0.5 parts of diptyltin oxide were placed in a four-necked flask equipped with a stirrer, a thermometer, and an inert gas introduction tube, and polyester polyol (C) was prepared in the same manner as in Example 1. I got it. The resulting resin (C) had a hydroxyl value of 100, a number average molecular weight of 2000, and a nonvolatile content of 80%. Next, in a four-necked flask equipped with a stirrer, a thermometer, and an inert gas inlet tube, Orestar P49-75S (a product manufactured by Mitsui Toatsu Chemical Co., Ltd., a prepolymer made by reacting trimethylolpropane with toluene diisocyanate),
Non-volatile content 75%, isocyanate group content 16% by weight
%) was taken, and 260 parts of methyl ethyl ketoxime was gradually added dropwise from the dropping funnel in the same manner as in Example 1 to carry out a reaction to obtain a blocked isocyanate resin (D). This resin (D) had an isocyanate group content of 11.9% and a solid content of 60%. A protective composition was manufactured using these resins with the following formulation. Polyester polyol (C) 100 parts Blocked isocyanate (D) 83.9 parts Catalyst SA-102 (Note) 2.6 parts Calcium carbonate 198 parts Carbon black 2 parts Calcium oxide 6 parts Mixing ratio of hydroxyl groups and isocyanate groups
100:100 (Note) Octylate of 1,8-diazabicyclo(5,4,0) undecene-7, Sanabbot Co., Ltd.
Product The protective composition thus produced was coated in the same manner as in Example 1 so that the dry coating film had a thickness of 340 μm, and baked and cured at 140° C. for 20 minutes. The coating film test results for this coating are shown in Table 2. Comparative Examples 1, 2, 3, 4, 5 MD1-CR-200 (product manufactured by Mitsui Nisso Urethane Co., Ltd., isocyanate group content % is 31%)
1,000 parts of xylene and 558 parts of xylene were charged, and 674 parts of trimethylethylketoxime was added dropwise from the dropping funnel, and the same reaction as in Example 1 was carried out to obtain a blocked isocyanate resin (F). The effective isocyanate group percentage of this resin (F) was 18.5%, and the solid content was 60%. Protective compositions were manufactured using these resins with the formulations shown in Table 1. Table of performance test results of coating film.
Shown in 2.

【table】

[Table] Comparative Example 6 A protective composition was obtained using the same formulation and production as in Example 1, except that 4 parts of calcium oxide was not blended. Coating film test method Adhesion (gobun test): Insert 10 cuts vertically and horizontally at 2 mm intervals into a sample coated with a predetermined film thickness on a 70 x 150 x 0.8 mm electrodeposited plate until it reaches the metal surface. , Apply cellophane tape to the cut part and peel it off to check whether the paint film has peeled off or not. The table shows the number of adhesion after the peel test.
The normal state test was conducted in an atmosphere of 20℃, the temperature deterioration test was performed after immersion in 40℃ hot water for 10 days, and the thermal deterioration test was conducted at 70℃.
After being kept in an atmosphere at ℃ for 10 days, a test was conducted in an atmosphere at 20℃. Cold resistance bending test: A sample coated with a specified film thickness on a 70 x 150 x 0.8 mm electrodeposited plate was kept in a -30°C low temperature chamber for 3 hours, then taken out and quickly placed with the coated side facing outward. Bend uniformly 180° along a 25mm diameter mandrel. Peel off the tape from this bent surface and examine the paint film for chips, cracks, cracks, etc. Impact resistance: A sample coated with a predetermined film thickness on a 70 x 150 x 0.8 mm electrodeposited plate was subjected to one impact from a 90° angle using an impact tester specified in JIS K-6830-26. Check for cracks and peeling of the paint film. Immediately after holding for 3 hours in an atmosphere of 20°C under normal conditions and -30°C in low temperatures. Salt water spray resistance test; A cut was placed in the center of the sample until it reached the metal on a 70 x 150 x 0.8 mm electrodeposited plate coated with a specified film thickness, and the test was held in a salt spray tester for 240 hours. , displays the maximum peeling width when the cut side is covered with cellophane tape. Chipping resistance test: Test 3-M-4 specified in JIS B1181 on a sample coated with a specified film thickness on a 70 x 150 x 0.8 mm electrodeposited plate.
A brass hexagonal nut with a diameter of 40 mm is inserted from a height of 3 m.
The nut was dropped onto each sample plate at an angle of 30° to the falling direction of the brass through the same cylinder of mm, and the weight of the falling nut until the scratches on the coating reached the metal surface was indicated. The water immersion deterioration test shows the test results after being immersed in 40°C warm water for 10 days. Paint stability test: Protective compositions for spray painting were tested at a temperature of 20°C using a BH type viscometer (rotation speed 20PRM rotor No. 5~
7) Measure the initial viscosity V ₀ . 45% of this composition
After storing for 10 days in an atmosphere at ℃, the viscosity V ₁ is measured at a measurement temperature of 20℃. The viscosity increase rate was determined by the following formula. Viscosity increase rate (%) = V ₁ −V ₀ /V ₀ ×100

【table】

[Table] As is clear from the foregoing detailed description and the table above, the present invention provides a protective composition with improved adhesion, cold flexibility, salt spray resistance, and especially chipping resistance. There is.

Claims (1)

[Scope of Claims] 1. (a) a polyol resin (A) having a hydroxyl value of 30 to 300; and (b) an effective isocyanate group content of 1 to 15% by weight.
It consists of a blocked isocyanate-containing resin (B), (c) a dissociation catalyst for blocked isocyanate (C), and (d) calcium oxide, and (e) the compounding ratio of effective isocyanate groups to hydroxyl groups is equivalent to (A). ):(B)=50:100
~100:50, (f) The amount of catalyst (C) is 0.01 to 5% by weight and the amount of calcium oxide is 1% by weight based on the total amount (solid content) of resin (A) and resin (B). ~10% by weight of a vehicle protective composition.