JP2857877B2 - Organic solvent type resin composition for chipping resistant coating - Google Patents

Description

The present invention relates to an organic solvent type chipping resistant resin comprising a novel and useful organic solvent type coating resin as an essential base resin component. A resin composition for coatings, particularly used as a chipping-resistant coating for automobiles,
The present invention relates to a novel and useful organic solvent type resin composition for chipping resistant paint.

[Conventional technology]

For example, in order to improve the durability of automobiles, not only the weather resistance of the top coat, but also the chipping resistance and rust prevention of the intermediate coat or undercoat applied to the lower layer, or the electrodeposition coating, in addition to the weather resistance of the top coat Sex is one of the important performances.

By the way, damage caused by the impact of sand and pebbles on the road or rock salt sprayed to prevent freezing on the moving car body is one of the major causes of car body metal corrosion. Various studies have been made to improve the resistance to collision (that is, chipping resistance).

For example, as disclosed in JP-A-57-190057, a one-pack type anti-chipping coating composition in which a component comprising a polyester and an amino resin and a component comprising a blocked isocyanate and an active hydrogen compound are mixed. Thing, 80
A coating composition comprising a urethane prepolymer in which terminal isocyanate groups are blocked and a polyaminopolyamide, as disclosed in JP-A-58-108261 or 58-10826, a technique of coating with a thick film of a micron or more. There is a technique of using a product as this kind of chipping-resistant paint.

However, in these conventional techniques, in order to obtain chipping resistance, there is a drawback that the coating workability is deteriorated because a thick film coating is absolutely necessary, or the blocking agent is dissociated. Require a high temperature, and the dissociated blocking agent causes various problems such as formation of coating defects such as armpits and pinholes.

[Problems to be solved by the invention]

Thus, as long as you follow the conventional technology,
It is also excellent in rust prevention, etc.
In addition, it has been extremely difficult to provide a resin composition for chipping-resistant paints that is also excellent in chipping resistance and the like.

However, the present inventors have enthusiastically started research on a resin composition for an anti-chipping paint which has a good appearance of a coating film and also has an excellent anti-chipping property.

Therefore, the problem to be solved by the present invention is, in part, to provide a resin composition for chipping-resistant paints, which has a good coating appearance and is also excellent in chipping resistance. It is to be.

[Means for solving the problem]

In view of the existence of various drawbacks in the prior art, such as a decrease in workability in thick film coating and poor appearance of the coating film, the present inventors have taken the present invention as described above into consideration. With the aim of resolving the problem to be solved by, especially, the chipping resistance of the coating film, the results of intensive studies have been made in order to remarkably enhance the chipping performance of the urethane prepolymer. ) Is further reacted with a monoamine compound (hereinafter, also referred to as monoamine), if necessary, and a resin composition containing the curing agent and a specific resin as described above are used. The various disadvantages of the conventional technology can be completely eliminated, and even in the thin film coating of about 10 to 40 microns, it exhibits extremely excellent chipping resistance. The present invention has been completed by finding out that the present invention is an object.

That is, the present invention basically comprises reacting a compound (a-1) having at least two hydroxyl groups in one molecule with an organic diisocyanate compound (a-2) as essential film-forming components. An organic material comprising a resin (A) obtained by reacting an urethane prepolymer (a-3) obtained by the reaction with an organic diamine compound (a-4) and a curing agent (B). Solvent type resin composition for chipping resistant coating or urethane prepolymer (a-3) obtained by reacting the above hydroxyl group-containing compound (a-1) with the above organic diisocyanate compound (a-2) Further, the present invention provides an organic solvent type resin composition for anti-chipping paint obtained by reacting the above-mentioned organic diamine compound (a-4) and further monoamine compound (a-5). Is intended to, specifically,
Preferably, the urethane prepolymer is obtained by reacting the compound (a-1) with the compound (a-2) such that the equivalent ratio of isocyanate group / hydroxyl group becomes 1.02 to 5.00. Urethane prepolymer (a-
In addition to the resin obtained by reacting the compound (a-4) so that the equivalent ratio of isocyanate group / amino group becomes 1 / 0.50 to 1 / 0.98 with respect to 3), And (b) an organic solvent-type resin composition for chipping-resistant coatings, or preferably, as the urethane prepolymer,
The urethane prepolymer (a-3) obtained by reacting 1) with the compound (a-2) so that the equivalent ratio of isocyanate group / hydroxyl group becomes 1.02 to 5.00, and further, In particular, the compound (a-4) and the compound (a-5) are combined with the isocyanate group in (a-3) / the amino group in (a-4) / the amino group in (a-5). An organic solvent type anti-chipping paint comprising a resin (A) obtained by reacting so as to have an equivalent ratio of 1 / 0.50 / 0.05 to 1 / 0.98 / 0.50, and a curing agent (B). It is intended to provide a resin composition for use.

Here, the aforementioned compound (a-1) having at least two hydroxyl groups in one molecule [hereinafter abbreviated as polyol]. Is not particularly limited as long as it satisfies the above definition. Among them, typical examples include copolymerization of β-hydroxyethyl (meth) acrylate with a vinyl monomer copolymerizable therewith. Acrylic polyol in a form obtained by reacting; polyester polyol in a form obtained by reacting neopentyl glycol with adipic acid; epoxy polyol in a form obtained by reacting an epoxy resin with an aliphatic or aromatic dibasic acid; Including polyether polyols such as polyethylene glycol, polyetherester polyol, polyurethane polyol, polycarbonate polyol, polyhydroxyalkane or alkyd resin, and the like,
And the mixture of these is mentioned.

Among them, first, a polyester polyol is generally obtained by a condensation reaction between a polyhydric alcohol and a polybasic acid. Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, and trimethylolpropane. , Pentaerythritol, sorbitol or hydrogenated bisphenol A are typical, while polybasic acids include succinic acid, adipic acid, azelaic acid,
Sebacic acid, phthalic acid, isophthalic acid, terephthalic acid,
Representative examples include tetrahydrophthalic acid, hexahydrophthalic acid, fumaric acid, maleic acid, trimellitic acid, pyromellitic acid, and anhydrides thereof.

In addition, polyesters obtained by ring-opening polymerization of lactones such as ε-caprolactone and methylcaprolactone are also typical.

Representative examples of the polyether polyol include polyethylene glycol, polypropylene glycol, polybutylene glycol, and polytetramethylene glycol.

Preferred examples of the organic diisocyanate (a-2) include hexamethylene diisocyanate, cyclohexyl-1,4-diisocyanate, isophorone diisocyanate, tolylene diisocyanate or diphenylmethane-4,4'-diisocyanate or a hydrogenated product thereof. And the like.

Examples of the organic diamine (a-4) include aliphatic diamines such as ethylenediamine, propylenediamine and hexamethylenediamine; aromatic diamines such as xylenediamine; and dicyclohexylmethane-diamine.
Alicyclic diamines such as 4,4'-diamine are typical, but dicyclohexylmethane-diamine is particularly preferred in terms of solubility in organic solvents and chipping resistance.
4,4'-Diamine is preferred.

The urethane prepolymer (a-3) used in the present invention is a polyol (a) as described above.
-1) and an organic diisocyanate (a-2) having an isocyanate group at a terminal obtained by reacting the same with a conventional method. Preferably, the equivalent ratio of isocyanate group / hydroxyl group (that is, NCO / OH) is It is obtained by reacting to 1.02 to 5.00.

When the equivalent ratio is smaller than 1.02, the obtained urethane prepolymer becomes a high molecular weight product, and therefore, the coating workability of the paint obtained using the same decreases, while the equivalent ratio is reduced. When it is larger than 5.00, the molecular weight of the urethane prepolymer is inevitably low, and therefore, the desired chipping resistance cannot be exhibited.

Urethane prepolymer (a-3) thus obtained
And an organic diamine (a-4) as described above and a monoamine (a-5) as described later, which is used as necessary, can react at an arbitrary ratio. The reaction is preferably performed so that the equivalent ratio of the isocyanate group present in the prepolymer (a-3) to the amino group present in the organic diamine (a-4) becomes 1 / 0.50 to 1 / 0.98.

Here, the equivalent ratio of the organic diamine (a-4) is 0.1.
If it is less than 50, the resulting resin has a low molecular weight and does not exhibit good chipping resistance, which is not preferred. On the other hand, the equivalent ratio of the organic diamine (a-4) is not preferable.
When the ratio is larger than 0.98, the obtained resin has a high molecular weight and coating workability deteriorates. Further, when the equivalent ratio of the organic diamine (a-4) exceeds 1.00, the resin is heated and dried after coating. This is also undesirable because the coating film becomes yellow.

The use of the monoamine (a-5) is completely optional in the present invention, but isocyanate group in (a-3) / amino group in (a-4) / amino group in (a-5) When the equivalent ratio of 1 / 0.50 / 0.05 to 1 / 0.98 / 0.5 is used, the solubility of the resulting resin in an organic solvent and the like are improved, which is desirable. When the equivalent ratio of the monoamine (a-5) is larger than 0.50, the resulting resin has a small molecular weight and does not exhibit good chipping resistance.

As the monoamine (a-5), known and commonly used monoamines can be used, and particularly typical examples thereof include aliphatic monoamines such as propylamine, n-butylamine, isobutylamine and hexylamine;
Aromatic monoamines such as phenylamine, benzylamine or α-phenylethylamine; alicyclic monoamines such as cyclohexylamine, di-n-butylamine, 3-propanolamine, 2-propanolamine or 3-methoxypropylamine is there.

The resin composition for a coating material according to the present invention is used after being diluted with various common organic solvents such as aromatic hydrocarbons, alcohols, esters, ethers, ketones and cellosolves.

As the curing agent (B) component used in the present invention, aminoplast, polyisocyanate, blocked polyisocyanate, or the like can be used.

Among such curing agent (B), the first typical as aminoplasts, C ₁ -C ₄ comprising monohydric alcohol etherified melamine resins, guanamine resins, acetoguanamine resins, benzoguanamine resins or urea resins, etc. However, use of a melamine resin is desirable from the viewpoint of weather resistance and the like.

Next, among the curing agents (B), representatives of polyisocyanates include aromatic diisocyanates such as tolylene diisocyanate or diphenylmethane diisocyanate; aliphatic diisocyanates such as hexamethylene diisocyanate or trimethylhexane diisocyanate; isophorone diisocyanate;
Alicyclic diisocyanates such as methylcyclohexane-2,4- (or -2,6-) diisocyanate, 4,4'-methylenebis (cyclohexylisocyanate) or 1,3-bis (isocyanatomethyl) -cyclohexane; A diisocyanate, a polyhydric alcohol such as ethylene glycol, polyether polyol (polyethylene glycol, polypropylene glycol or polycaprolactone polyol), trimethylolethane or trimethylolpropane, or a low molecular weight compound having a functional group capable of reacting with an isocyanate group. Polyester resin (including oil-modified type), acrylic copolymer, adduct with water or the like, or burette; copolymer of various diisocyanates as described above (oligomer) Including a);. Furthermore,
An essential component is a vinyl monomer having both isocyanate groups and copolymerizable unsaturated bonds, such as an equimolar addition product of 2-hydroxypropyl (meth) acrylate and hexamethylene diisocyanate or isocyanate ethyl (meth) acrylate. Copolymer;
61-72013 Patent as disclosed in Japanese Unexamined, C ₂ -C ₈ becomes alkylene -, cycloalkylene - a or aralkylene diisocyanates and C ₁₀ -C ₄₀ becomes diol, in the presence of isocyanurate titanate catalyst It is obtained by reacting.
Examples include polyisocyanates containing an isocyanurate ring and soluble in non-polar organic solvents.

Further, among the curing agents (B), representative ones as blocked polyisocyanates include various polyisocyanates as described above, phenolic, lactam,
Examples thereof include those blocked with various commonly used blocking agents such as alcohols, amines, imines, imides, imidazoles and oximes.

In addition to the resin composition for coating of the present invention, various resin components such as polyester resin, vinyl resin, especially acrylic resin, alkyd resin, epoxy resin or polyamide resin; titanium oxide, calcium carbonate,
Needless to say, various filler components such as precipitated barium sulfate, silica powder and metal powder, as well as various additive components such as pigments, dyes or curing accelerators can be blended.

The thus-obtained resin composition for coating of the present invention is a so-called forced drying type in which a coating is formed by heating or heating at a temperature of 60 to 250 ° C. to form a crosslinked structure (reticulation). Although it can be used as a heat-curable coating, it is particularly preferable to use it as a chipping-resistant coating.

At that time, the coating resin composition of the present invention is formed into a coating by a conventional method, and is applied to an object to be coated by a desired method. Typical coating methods include a roll coater method, a spray method, There are electrostatic spraying, brushing or dipping, and the objects to be coated are metal materials, metal products, wood, wood products, glass plates, glass processed products,
Ceramac products or plastics products are typical.

〔Example〕

Next, the present invention will be described in more detail with reference examples, examples and comparative examples. In the following, all parts and percentages are by weight unless otherwise specified.

Reference Example 1 (Example of preparing polyester polyol) 584 parts of adipic acid and 5 of neopentyl glycol
20 parts were charged into a reaction vessel equipped with a stirrer, and while removing generated water from the system, the temperature was raised from room temperature to 210 ° C. over 6 hours, and further maintained at the same temperature for 3 hours. After polycondensation, the temperature was lowered to 100 ° C., and 640 parts of toluene was added to obtain a solution of the target polyol having a number average molecular weight of 1,000 and a hydroxyl value (solid content) of 116. Hereinafter, this is abbreviated as polyol (a-1-1).

Reference Example 2 (Preparation example of alkyd resin) 29 parts of soybean oil fatty acid, 22 parts of isophthalic acid, 19 parts of adipic acid, 10 parts of 1,6-hexanediol, 31 parts of trimethylolpropane, and di-n- 0.02 parts of butyltin oxide was charged into a reaction vessel equipped with a stirrer, and room temperature to 220 ° C while removing generated water outside the system.
The temperature was raised to 6 ° C. over 6 hours, and further maintained at the same temperature for 4 hours to continue the condensation. After the temperature was lowered to 100 ° C., 43 parts of toluene was added, and the number average molecular weight was 1,300 and the hydroxyl value ( A solution of the target resin having a solid content of 150 was obtained. Less than,
This is abbreviated as polyol (a-1-2).

Reference Example 3 (Preparation example of polyether polyol) 300 parts of toluene and 100 parts of isopropyl alcohol were added to 600 parts of "PEG1000" (polyethylene glycol manufactured by Sanyo Chemical Industries, Ltd .; number average molecular weight = about 1,000), and The target polyol was obtained by uniformly dissolving. Hereinafter, this is abbreviated as polyol (a-1-3).

Example 1 806 of the polyol (a-1-1) obtained in Reference Example 1
Add 130.5 parts of tolylene diisocyanate to parts (NCO / O
In a reaction vessel equipped with a stirrer, a thermometer, and a condenser, 0.25 part of stannous octylate was further added to the mixture, and the mixture was heated to 80 ° C and heated at the same temperature for 5 hours. The reaction was carried out for an hour to obtain a urethane prepolymer having an isocyanate equivalent of 1,285.

Next, after the temperature was lowered to 20 ° C., 19.7 parts of ethylenediamine, 6.6 parts of di-n-butylamine and 104.5 parts of isobutyl alcohol were added, and the temperature was raised to 50 ° C.
After a reaction at the same temperature for 3 hours, a resin solution having a nonvolatile content of 60% was obtained. Hereinafter, this is abbreviated as coating resin (A-1).

Example 2 Instead of 806 parts of the polyol (a-1-1), 534 parts of the polyol (a-1-2) obtained in Reference Example 2 was used, and 130.5 parts of tolylene diisocyanate was used. In the same manner as in Example 1 except that 555 parts of isophorone diisocyanate were used, a urethane prepolymer having an isocyanate equivalent of 371 was obtained.

Next, after the temperature was lowered to 20 ° C, 154.1 parts of dicyclohexylmethane-4,4'-diamine and 303.9 parts of isobutyl alcohol were added, the temperature was raised to 50 ° C, and the reaction was carried out at the same temperature for 3 hours. Thus, a resin solution having a nonvolatile content of 70% was obtained. Hereinafter, this is abbreviated as coating resin (A-2).

Example 3 Instead of 806 parts of the polyol (a-1-1), 833 parts of the polyol (a-1-3) obtained in Reference Example 3 was replaced with
First, an intermediate compound of a urethane prepolymer having an isocyanate equivalent of 700 was obtained in the same manner as in Example 1 except that 217.5 parts of tolylene diisocyanate was used.

Next, the temperature was lowered to 20 ° C., 31.5 parts of ethylenediamine and 39.4 parts of diethanolamine were added, the temperature was raised to 50 ° C., and the mixture was reacted at the same temperature for 3 hours to obtain a resin solution having a nonvolatile content of 70.3%. Hereinafter, this is referred to as paint resin (A-3).
Abbreviated.

Example 4 Using the coating resin (A-1) obtained in Example 1,
The mixture was mixed at the compounding ratio shown in Table 1 and dispersed using a bead mill to prepare a chipping-resistant paint.

Then, using the paint thus obtained, a usual polyester-melamine-based intermediate paint, and a usual amino-alkyd-based topcoat, under the conditions shown in Table 2, by ordinary air spray coating. And dried to produce a test piece (cured coating film).

The plate to be coated was JIS treated with "Bonderite 37" (a rust inhibitor manufactured by Nippon Parker Rising Co., Ltd.).
A cold rolled steel sheet specified in G-3310 is electrodeposited with an epoxy-based polyamino resin electrodeposition primer to a thickness of about 20 microns and then baked at 170 ° C for 30 minutes. In any of the above test plates, first, a chipping-resistant paint and / or a polyester-melamine-based intermediate paint is applied on the substrate to be coated, that is, on the electrodeposition coating layer, and then the amino alkyd is applied. It is obtained by repeatedly applying a system topcoat paint, among which the case of using an anti-chipping paint is an example product,
On the other hand, a comparative example is a case where only the polyester-melamine-based intermediate coating is used instead of the chipping-resistant coating.

For each test piece, the following various performances were compared.

 The results are summarized in Table 2.

(1) Appearance of Coating Film The appearance of the top coating film was visually evaluated and judged comprehensively on gloss, sharpness and smoothness of the coating film.

(2) Chipping resistance test i) Test equipment: "Grabellometer" manufactured by Suga Test Instruments Co., Ltd. ii) Type of stone to be discharged: No. 7 crushed stone iii) Weight of discharged stone: 50.0 g iv) Discharge Air pressure: 4 kg / cm ² v) Test temperature: -20 ° C Examples 5-7 Resins for paints (A-2)-(A) obtained in Examples 2-3
Except having changed to use -3), each anti-chipping paint was obtained in the same manner as in Example 4.

[Effects of the Invention] As is clear from the results in Table 2, the resin composition for a coating of the present invention has a good coating appearance regardless of whether or not an intermediate coating is used. Therefore, it is also extremely excellent in chipping resistance.

Continuation of front page (72) Inventor Chizuru Tanaka 2-3-1-102 Chiyoda, Takaishi-shi, Osaka (56) References JP-A-62-270614 (JP, A) JP-A-61-155417 (JP, A) JP-A-59-71324 (JP, A)

Claims (4)

(57) [Claims] 1. A compound (a-1) having at least two hydroxyl groups in one molecule as an essential constituent component
And a resin (A) obtained by reacting an urethane prepolymer (a-3) obtained by reacting an organic diisocyanate compound (a-2) with an urethane prepolymer (a-3) obtained by reacting An organic solvent-type resin composition for chipping-resistant coating, characterized by containing an agent (B). 2. A resin (A) comprising a compound (a-1) having at least two hydroxyl groups in one molecule and an organic diisocyanate compound (a-2) having an isocyanate group / hydroxyl group equivalent ratio of 1.02. The urethane prepolymer (a-3) obtained by reaction so as to have an isocyanate group / amino group ratio of 1 / 0.50 to 1 / 0.98
The composition according to claim 1, which is a resin obtained by reacting an organic diamine compound (a-4) such that 3. Compounds (a-1) each having at least two hydroxyl groups in one molecule as essential constituents
And an organic diisocyanate compound (a-2) to obtain a urethane prepolymer (a-3), which is further reacted with an organic diamine compound (a-4) and a monoamine compound (a-5). Resin (A),
A resin composition for an organic solvent-type chipping-resistant coating, comprising a curing agent (B). 4. A resin (A) comprising a compound (a-1) having at least two hydroxyl groups in one molecule and an organic diisocyanate compound (a-2) having an isocyanate group / hydroxyl group equivalent ratio of 1.02. To 5.00, the organic diamine compound (a-4) and the monoamine compound (a) were further added to the urethane prepolymer (a-3) obtained by the reaction.
-5) is replaced with the isocyanate group in (a-3) / (a-
The equivalent ratio of the amino group in 4) / the amino group in (a-5) is
The composition according to claim 3, which is a resin obtained by reacting so as to be 1 / 0.50 / 0.05 to 1 / 0.98 / 0.50.