KR20120064832A - The resin mixture and synthetic method of the resins for high build primer which is applicable on automotive pre-coated coatings - Google Patents

Abstract

PURPOSE: A resin mixture composition and a manufacturing method thereof are provided to be used for vehicle free coated paint manufacturing and to improve water resistance, corrosion resistance, weatherability, workability, and shock resistance. CONSTITUTION: A resin mixture composition comprises highly flexible polyester polyol resin, caprolactone-modified resin, and urethane-modified polyester blocked resin. A manufacturing method of highly flexible polyester polyol resin comprises the following steps: a step of mixing 20-25 parts by weight of trimethyl propanediol, 18-20 parts by weight of neopentyl glycol, and 8-9 parts by weight of adipic acid, 20-25 parts by weight of isophthalic acid, and 0.1-0.2 parts by weight of dibutyltin oxide which is an esterification catalyst; a step of obtaining a synthesized material by performing esterification at 200~220 deg. Celsius; and a step of diluting synthesized material into 20-30 parts by weight of propylene carbonate.

Description

Resin Mixture and Synthetic method of the Resins for high build primer which is applicable on automotive pre-coated coatings}

The present invention is a high-elastic thick film one-component polyurethane coating binder which can be applied to a precoated paint coating system for automobiles. Mixed composition of high-flexibility polyester polyol resin and caprolactone-modified and urethane-modified polyester blocked resin that can exhibit physical properties such as water resistance, corrosion resistance, weather resistance, processability and impact resistance along with excellent workability for thick film work And to a manufacturing method.

Automotive paints have been commercialized by intensive R & D on the exterior and physical properties, but as the demand for development of environmentally friendly products has recently emerged, it is gradually demanding the development of products that can simultaneously realize appearance, physical properties and eco-friendliness. have.

In line with these demands, the development of an eco-friendly automotive coating system by shortening the non-eco-friendly painting process, the development of new automotive paints and coating systems that can simultaneously reduce costs, improve productivity, reduce energy and reduce labor costs As a countermeasure technology, it is called for the development of color steel sheet manufacturing and modular application technology leading the high formability of automobile in the form of shortened integrated process.

Pre-coated metal system, the leading steel plate technology applied in industrial and construction fields, is applied to various real-life materials fields, but most of them are developed and applied mainly for rust prevention and molding processing characteristics. It is characterized by the fact that it is made and the application of beautiful appearance such as automobile and high gloss clear coat has not been secured yet. The pre-coated metal system, which is actively applied to home appliances, can exhibit relatively excellent appearance and high gloss characteristics. Have been developed.

However, in order to apply these technologies to the automotive industry, prior studies on applied technologies for curved molding are essential to maintain the problem of cracking of the painted surface due to the difference in the material properties of the steel sheet and the painted surface when forming the curved surface, and to maintain the sensibility after molding. In order to manufacture and modularize the high-strength lead-in color steel sheet for automobiles, the lead-in process using a high-elastic primer or a high-speed roll coater is essential for the lead- and post-processed steel sheet. The paints such as core layer wall primer and metal top coat which can realize uniform color according to high speed system interlayer coating, and top coat clear coat which have functionalities such as cold resistance chipping and scratch resistance and acid resistance should be developed. Which can present these required properties It has not been developed.

In particular, high-elastic primer used for automotive steel coating should be capable of sufficient thick film of 30㎛ or more by high temperature and one-time coating process, and the present inventors have a caprolactone-modified and urethane-modified polyester which can exhibit these required properties when the primer is manufactured. By developing a mixed composition and a manufacturing method of a block resin and a highly flexible polyester polyol resin, it is suitable for corrosion resistance and impact resistance suitable for painting steel sheets for automobiles even after a sufficient thick film composition of 50 µm or more, and in corners and bends during plastic processing or deep processing. Thick film-type primer manufacturing technology applicable to automobile precoated paints that can control the coating film breakage that can be generated is implemented.

Corrosion resistance and external impact suitable for lead sheet and post-processed steel sheet, and cracks in the corners and bends of plastic sheet or deep processing during steel sheet processing can be controlled. The low molecular weight, highly flexible polyester polyol resin showing excellent coating flexibility and crosslinking with the polyol resin to form a coating film, even if a thick coating film having a thickness of 50 μm or more with excellent corrosion resistance and impact resistance, An object of the present invention is to provide a caprolactone-modified and urethane-modified polyester-blocking resin mixed composition and a method of preparing the coating film which does not occur and does not cause appearance problems such as paping and bubbles.

The present invention for achieving the above object is mixed with trimethylpropanediol, neopentylglycol and adipic acid, isophthalic acid and the like in an appropriate equivalent ratio to prepare a highly flexible polyester polyol resin through esterification dehydration condensation reaction, and trimethylolpropane And caprolactone and dimethylolpropionic acid were mixed in an appropriate equivalence ratio, and cyclohexanite dimethanol, neopentylglycol and dodecanedioic acid were mixed with diol intermediate obtained through ring opening and addition reaction of caprolactone, followed by esterification dehydration condensation reaction. Caprolactone modification and urethane modification having high elasticity and high corrosion resistance in which the remaining active isocyanate functional groups of the caprolactone-modified and urethane-modified polyester resins obtained by crosslinking diisocyanate through urethane-modified at a specific equivalent ratio are blocked with caprolactam and methyl ethyl ketoxime. It provides a method for producing a resin mixture composition comprising a manufacturing step of mixing a polyester block resin in a specific ratio.

According to the present invention by means of the above-mentioned problem solving means, even after forming a thick coating film of 50㎛ or more by a single coating process, the corrosion resistance and external impact suitable for the lead sheet / post-processed steel sheet, the corner portion and the bent portion during steel sheet plastic processing or deep processing It has the flexibility to control the cracks in the coating and the like, and the boiling problem of the coating does not occur in the high-temperature baking section and the appearance problems such as popping and bubbles do not occur. By using a primer paint, all of the physical properties represented by a coating film composed of 20 μm or less can be exhibited, and thus, a paint technology for applying a coating of automotive steel sheet to a precoated metal coating process can be realized.

Hereinafter, a preferred embodiment of the method for producing a highly flexible polyester polyol resin, caprolactone-modified and urethane-modified polyester block resin and the mixed composition of the present invention.

Highly flexible polyester polyol resin and caprolactone-modified and urethane-modified polyester block resin mixture composition of the present invention can be specifically realized through the following manufacturing process.

Highly flexible polyester polyol resin is 20 to 25 parts by weight of trimethylpropanediol, 18 to 20 parts by weight of neopentyl glycol and 8 to 9 parts by weight of adipic acid, 20 to 25 parts by weight of isophthalic acid and dibutyltin oxide 0.1 as an ester reaction catalyst. It is prepared by diluting 20 parts by weight to 30 parts by weight of propylene carbonate in a reaction product which is mixed with ˜0.2 parts by weight and esterified at a temperature of 200 to 220 ° C.

Synthetic resin composition prepared by the above process has a hydroxyl value of 225 ~ 245, a number average molecular weight of 650 ~ 700, a weight average molecular weight of 1,100 ~ 1,300 as a highly flexible polyester polyol resin having a linear polymer model, In spite of the low molecular weight, the high hydroxyl value leads to the formation of a coating film with high degree of crosslinking through the urethane bond formed through the reaction with the caprolactone-modified and urethane-modified polyester block resin. This highly flexible polyester polyol resin is crosslinked with the main chain when forming the coating film, and acts as a main variable for controlling the flexibility and elasticity of the crosslinked coating film, and the corrosion resistance including mechanical properties and chemical resistance, such as coating strength, as the branch chain of the polymer main chain. . This can be explained in detail as follows.

When the hydroxyl value exceeds 250, it exhibits excessively high degree of urethane crosslinking degree when forming the coating film, which lowers the flexibility of the coating film and does not exhibit the processability required for automotive coatings. It does not satisfy the corrosion resistance required by the paint. In addition, if the number average molecular weight is less than 650 or the weight average molecular weight is less than 1,100, the length of the branch chains that provides the flexibility of the coating film is short, so that the urethane crosslinked structures of the polymer chains are adjacent to each other, resulting in poor workability and low mechanical properties. The problem of deterioration arises. On the other hand, when the number average molecular weight exceeds 700 or the weight average molecular weight exceeds 1,300, branch chains that provide the flexibility of the coating film have a complex structure, and workability is degraded. A problem arises.

Caprolactone-modified and urethane-modified polyester block resins were mixed with 1 to 1.5 parts by weight of trimethylolpropane, 3 to 7 parts by weight of caprolactone, and 0.2 to 0.5 parts by weight of dimethylolpropionic acid. Diol intermediate having ~ 150, 7-9 parts by weight of cyclohexane dimethanol, 5-6 parts by weight of neopentylglycol and 15-20 parts by weight of dodecanedioic acid, followed by esterification dehydration condensation reaction 20 parts by weight of urethane-modified, the remaining active isocyanate is prepared by blocking 5-7 parts by weight of caprolactam and 0.1-0.5 parts by weight of methyl ethyl ketoxime by diluting with 35-40 parts by weight of propylene carbonate.

The resin composition thus obtained has a number average molecular weight of 4,000 to 4,500, a weight average molecular weight of 9,000 to 12,000, and has an NCO equivalent of 4,000 to 5,000 when all of the blocked isocyanates are dissociated. The caprolactone modified and urethane modified polyester blocked resins are crosslinked with the highly flexible polyester polyol resins described above as the main chain of the polymer to form a coating film, which is a flexible, linear shape provided by the modification of the caprolactone ring-opened in the molecule. It contains a molecular structure that exhibits high elastic properties, and also contains a urethane bond provided in the molecule by the saturated ring molecular structure of dimethyl hexamethanol and the modification of isophorone diisocyanate, thereby maximizing such high elastic properties as well as excellent corrosion resistance and It shows weather resistance. In addition, the terminal groups of the polymer chain contain an isocyanate functional group blocked with caprolactam and methylethylketoxime, and are dissociated during the heat drying process to crosslink with the hydroxyl group of the highly flexible polyester polyol resin to form a coating film. Caprolactam and methylethylketoxime blocking agents have characteristic dissociation temperatures, so that the rate of film formation can be controlled according to the temperature and time variables of the heat drying process. In order to show the characteristic properties of this caprolactone-modified and urethane-modified polyester block resin, it should be prepared considering the following matters.

When the total amount of caprolactone and isophorone diisocyanate exceeds 25 parts by weight, the flexibility is greatly reduced, and the processability required for automotive coatings is not satisfied. The total amount of caprolactone and isophorone diisocyanate is 20 weights. When designed to less than a part, the molecular weight of a polymer chain falls, a urethane bond falls, and the mechanical strength of a coating film falls. In addition, even if the total amount of caprolactone and isophorone diisocyanate used is in the range of 20 to 25, when the amount of caprolactone is used is less than 3 parts by weight, the flexibility is lowered and the processability cannot be satisfied. If the flexibility is excessive, the mechanical strength of the coating film, such as hardness, does not satisfy all the standards required for automotive paints. In the case of cyclohexane dimethanol, when used in excess of 10 parts by weight, it may exhibit better corrosion resistance and weather resistance, but the hardness of the coating film becomes too high, causing problems in processability, and when used below 6 parts by weight, impact resistance and weather resistance are deteriorated. A problem arises. In the case of dodecanedioic acid, when less than 15 parts by weight is used, workability is lowered. When it is used in excess of 20 parts by weight, the hardness of the coating film is lowered. Neopentylglycol should be used in an amount of 5 to 7 parts by weight in order to adjust the hydroxyl value to obtain appropriate urethane modification and blocked isocyanate functional groups. On the other hand, when the ratio of isocyanate functional groups blocked at the terminal groups of the polymer chain is less than NCO equivalent of 4,000, the use ratio of the high-flexibility polyester polyol resin should be increased to use the same equivalent, which leads to excessively high flexibility of the polymer of the crosslinked coating film. If the mechanical strength of the coating film is weakened, and the NCO equivalent is less than 4,000, the amount of the highly flexible polyester polyol resin is not increased. This causes a problem in workability of the coating film. On the contrary, when the NCO equivalent exceeds 5,000, the use cost of the highly flexible polyester polyol is reduced, and the workability of the crosslinked coating film is greatly reduced.In this case, the use cost of the highly flexible polyester polyol resin is reduced even though the NCO equivalent is less than 4,000. Otherwise, excess hydroxyl groups remain active in the polymer of the crosslinked coating film, making it difficult to completely dry and hinder the formation of the coating film. Most of the active isocyanates in the polymer are blocked using 5-7 parts by weight depending on the equivalent of active isocyanate using caprolactam as the main blocking agent, and unblocked using a small amount of 0.1-0.5 parts by weight of methyl ethyl ketoxim having excellent blocking reactivity. There is no residual isocyanate present. At this time, if it exceeds the usage ratio within the range, it acts as an impurity, and when the coating is formed, it causes paping, bubble, or crete, which causes problems in the appearance of the coating. Storage performance is reduced.

 5 to 10 parts by weight of the highly flexible polyester polyol resin thus prepared and 90 to 95 parts by weight of caprolactone-modified and urethane-modified polyester block resins were mixed at room temperature to prepare a thick film-type high-elastic primer that can be applied to automotive precoated paints. To prepare a mixed resin composition.

When more than 10 parts by weight of the highly flexible polyester polyol resin is used, the amount of unreacted active hydroxyl acid in the dry curing may be excessive to hinder the formation of the coating film, and the caprolactone-modified and urethane-modified polyester block resins are used in excess of 95 parts by weight. When the film is formed, crosslinking reaction between intramolecular NCOs, which is a side reaction, occurs, thereby decreasing the flexibility of the molecular chain, thereby degrading the processability of the coating film.

The mixed composition of the highly flexible polyester polyol resin and the caprolactone-modified and urethane-modified polyester-blocking resin prepared by the above-mentioned formulations is generally shown in conventional commercialized precoated paints even when a 50-micron thick film is formed. In addition to exhibiting all the physical properties, it is possible to implement a thick-film coating technology that can be applied to the coating of automotive steel sheet in the pre-coated coating process.

Hereinafter, the present invention will be described in detail based on the following Preparation Examples and Examples, but the Examples of the present invention do not necessarily limit the scope of the present invention.

1. Preparation of High Flexibility Polyester Polyol Resin and Caprolactone Modified and Urethane Modified Polyester Blocking Resin Mixture Composition

1-1. High flexibility polyester Polyol  Preparation of Resin

Preparation Example 1, Preparation Example 2 and Preparation Example 3 of the high-flexibility polyester polyol resin were prepared using the compounds of the components as shown in Table 1 below.

Preparation Example of Highly Flexible Polyester Polyol Resin (unit: parts by weight) Ingredient Name Preparation Example 1 Production Example 2 Production Example 3 Trimethylpropanediol 23.0 25.0 23.0 Neopentyl glycol 20.0 18.0 18.0 Adipic acid 10.0 8.0 10.0 Isophthalic acid 23.0 25.0 25.0 Dibutyl tin oxide 0.1 0.1 0.1 Propylene carbonate 24.0 24.0 24.0 Sum 100.1 100.1 100.1

Trimethylpropanediol, neopentylglycol, adipic acid, isophthalic acid and dibutyltin oxide were mixed in the same component ratios as Preparation Example 1, Preparation Example 2 and Preparation Example 3 above, placed in a round bottom flask and the device was recovered using a glycol recovery system. After the esterification dehydration reaction proceeds until the acid value is 2 or less at a temperature of 200 ~ 220 ℃ was prepared by diluting with propylene carbonate of the same component ratio as in the preparation example above, [Table 2 The resin composition which shows the characteristics similar to the content of] was synthesize | combined.

Synthesis result of preparation example of high flexibility polyester polyol resin Properties Preparation Example 1 Preparation Example 2 Production Example 3 Remarks Viscosity (Gardener #) Z2 / Z3 Z3 Z3 25 ℃ Fisheries 225 235 245 KOH / mg Number average molecular weight (Mn) 660 680 680 GPC Weight average molecular weight (Mw) 1,150 1,200 1,200 GPC Nonvolatile matter (% by weight) 75.0 75.0 75.0 110 ℃ X 1hr

The preparation examples synthesized above are particularly characterized by having a hydroxyl value of 225, Preparation Example 2 having a hydroxyl value of 235, and Preparation Example 3 having a hydroxyl value of 245.

1-2. Caprolactone Modification  And preparation of urethane-modified polyester blocking resin

Preparation Example 4, Preparation Example 5 and Preparation Example 6 of the caprolactone-modified and urethane-modified polyester-blocking resins were prepared using the compounds of the components shown in Table 3 below.

Preparation Example of Caprolactone Modified and Urethane Modified Polyester Blocking Resin (Unit: parts by weight) Ingredient Name Production Example 4 Production Example 6 Production Example 6 Trimethylolpropane 1.0 1.0 1.0 Caprolactone 3.0 5.0 7.0 Dimethylolpropionic acid 0.4 0.4 0.4 Cyclosiloxane Dimethanol 8.0 8.0 8.0 Neopentyl glycol 6.5 5.5 5.5 Dodecanedioic Acid 20.0 15.0 15.0 Isophorone diisocyanate 17.0 18.0 18.0 Caprolactam 6.0 7.0 7.0 Methyl ethyl ketoxime 0.1 0.1 0.1 Propylene carbonate 38.0 38.0 38.0 Sum 100.0 100.0 100.0

Trimethylolpropane, caprolactone, and dimethylolpropionic acid were mixed in the same composition ratio as in Preparation Example 4, Preparation Example 5, and Preparation Example 6 above, put into a round bottom flask, and the device was configured with a glycol recovery system. Caprolactone ring opening and esterification dehydration are carried out at a temperature of 210 ° C. to sufficiently react to an acid value of 2 or less to prepare a diol intermediate having a hydroxyl value of 145 to 150. Add Iksan to the same component ratios as in Preparation Example 4, Preparation Example 5 and Preparation Example 6, and then fully reacted to an acid value of 2 or less through an esterification dehydration reaction at 200 to 220 ° C, and then cooled to 45 ° C or less. When the contents of the flask are cooled to 45 DEG C or lower, isophorone diisocyanate in the same amount as in the contents of Preparation Example 4, Preparation Example 5 and Preparation Example 6 was added dropwise over 1 hour. At this time, the self-heating of the urethane modification process is to be maintained at 75 ~ 85 ℃. After the dropping was completed, the reaction was carried out at 90 ° C. until the NCO equivalent weight was 1,700 to 1,800, and then caprolactam was added in the same component ratio as in Preparation Example 4, Preparation Example 5 and Preparation Example 90, and then 90 After holding the reaction for 2 hours at ℃, methyl ethyl ketoxime was added to the same component ratios as in Preparation Example 4, Preparation Example 5 and Preparation Example 6, and then the holding reaction was carried out at 90 ° C until the NCO equivalent was 20,000 or more. After proceeding, the propylene carbonate is prepared by diluting using the same component ratios as in Preparation Example 4, Preparation Example 5 and Preparation Example 6 above. The caprolactone-modified and urethane-modified polyester-blocking resins thus prepared showed the characteristics as shown in Table 4 below.

Synthesis Results of Preparation of Caprolactone Modified and Urethane Modified Polyester Blocking Resin Properties Production Example 4 Production Example 5 Production Example 6 Remarks Viscosity (Gardener #) Z4 Z5 Z6 25 ℃ Blocked NCO Equivalent 4,400 4,500 4,500 Number average molecular weight (Mn) 4,100 4,300 4,400 GPC Weight average molecular weight (Mw) 10,000 11,000 11,500 GPC Nonvolatile matter (% by weight) 58.0 58.0 58.0 110 ℃ X 1hr

The preparation examples synthesized above are characterized in that the caprolactone was used in the range of 3 to 7 parts by weight, and the sum of the component ratios of the caprolactone and isophorone diisocyanate is in the range of 20 to 25 parts by weight. . In particular, Preparation Example 4 is characterized in that the constituent ratio of the caprolactone used is 3 parts by weight, the sum of the caprolactone and isophorone diisocyanate is 20 parts by weight, Preparation Example 5 is 5 parts by weight of caprolactone, It is characterized in that the sum of caprolactone and isophorone diisocyanate is 23 parts by weight, and Preparation Example 6 is characterized in that the component ratio of caprolactone is 7 parts by weight, and the sum of caprolactone and isophorone diisocyanate is 25 parts by weight.

1-3. High flexibility polyester Polyol resin Caprolactone Modification  And urethane modified polyester Block resin  Mixed composition manufacturing

Each of the preparation examples prepared according to the above-described method for producing a highly flexible polyester polyol resin of 1-1 and a method for producing a caprolactone-modified and urethane-modified polyester block resin of 1-2, according to the equivalent ratio of hydroxyl group and blocked isocyanate Mixing in each ratio to prepare a mixed composition of a highly flexible polyester polyol resin and caprolactone-modified and urethane-modified polyester blocking resin, the details are as follows.

10 parts by weight of Preparation Example 1 synthesized by the method of manufacturing a highly flexible polyester polyol resin of 1-1 and 90 parts by weight of Preparation Example 4 synthesized by the method of producing caprolactone-modified and urethane-modified polyester blocking resin of 1-2 It is prepared by mixing at room temperature using a stirrer at a stirring speed of 50 ~ 100rpm.

10 parts by weight of Preparation Example 1 and 90 parts by weight of Preparation Example 5 were prepared by mixing in the same manner as in Preparation Method of Example 1 above.

10 parts by weight of Preparation Example 1 and 90 parts by weight of Preparation Example 6 were prepared by mixing in the same manner as in Preparation Method of Example 1 above.

7 parts by weight of Preparation Example 2 and 93 parts by weight of Preparation Example 4 were prepared by mixing in the same manner as in Preparation Method of Example 1 above.

7 parts by weight of Preparation Example 2 and 93 parts by weight of Preparation Example 5 were prepared by mixing in the same manner as in Preparation Method of Example 1 above.

7 parts by weight of Preparation Example 2 and 93 parts by weight of Preparation Example 6 were prepared by mixing in the same manner as in Preparation Method of Example 1 above.

5 parts by weight of Preparation Example 3 and 95 parts by weight of Preparation Example 4 were prepared by mixing in the same manner as in Preparation Method of Example 1.

5 parts by weight of Preparation Example 3 and 95 parts by weight of Preparation Example 5 were prepared by mixing in the same manner as in Preparation Method of Example 1 above.

5 parts by weight of Preparation Example 3 and 95 parts by weight of Preparation Example 6 were prepared by mixing in the same manner as in Preparation Method of Example 1 above.

(Comparative Example 1)

Commercially available polyester polyol and blocked isocyanate resin mixture composition for general precoated paint

2. Physical property test

After coating the resin composition prepared according to the Examples and Comparative Examples to prepare a specimen to evaluate the physical properties, the details of the physical properties evaluation method and results are described as follows.

end. Manufacture of paint

Like the components in the following Table 5, the paint was prepared by applying the components and production ratios of the company's existing commercial coating products for general precoated metal.

(Unit: parts by weight) number Ingredient Name Weight ratio Example Comparative example One Each resin mixture composition prepared by the method of Examples 1-9. Commercial product of resin mixture composition for general precoated paint (product of Fiji Korea) 50.0 2 Titanium dioxide (pigment) Titanium dioxide (pigment) 16.0 3 Inorganic pigments Inorganic pigments 1.0 4 Polypropylene Wax Polypropylene Wax 0.5 5 Acrylate antifoaming agent Acrylate antifoaming agent 0.5 6 Acrylate Crab Slipper Acrylate Crab Slipper 0.5 7 Dibutyltin dilaurate Dibutyltin dilaurate 0.5 8 Silicon dioxide silica Silicon dioxide silica 2.0 9 Butyl Carbitol Acetate Butyl Carbitol Acetate 9.0 10 Butyl Carbitol Butyl Carbitol 10.0 11 Kocosol # 150 Kocosol # 150 10.0

I. Manufacture of specimens

Chromatized GI or GALVALUME is carried on pre-treated specimens by coating our thick film type precoated undercoat with dry film 30 ~ 50㎛, drying temperature 240 ~ 250 ℃, baking time 40 ~ 60 seconds. The paints prepared according to the method of Examples 1 to 9 were each prepared by fabricating a thick film under the conditions of a coating film thickness of 50 μm, a material surface temperature of 240 to 250 ° C., and a baking time of 40 to 60 seconds. Two specimens each having a coating thickness of 20 μm and 60 μm were prepared under the conditions of the material surface temperature of 240 to 250 ° C. and the baking time of 40 to 60 seconds.

All. Test Methods

The prepared specimens were evaluated for physical properties for each test item as shown in Table 6 below.

Test Items Assessment Methods Gloss (Gloss 60 °) Initial film gloss measurement with a 60 ° gloss meter Coating Hardness (MEK Rubs) Measure the number of times the coating film is peeled off by rubbing the surface of the coating film with MEK solvent Pencil hardness Coating hardness is measured using UNI-Pencil (Mitsubishi) Machinability (T-Bend) Fold the specimen at an angle of 180 ° to measure the degree of peeling of the coating Adhesiveness (C.E.T) 5 mm measurement with Erichsen tester Impact Resistance Measured with Dupont tester under 1 / 2Ⅹ50cmⅩ500g Acid resistance 96 hours spot test with 5% hydrochloric acid solution at room temperature Alkali resistance 96 hours spot test with 5% sodium hydroxide solution at room temperature Boiling water & adhesion Adhesion (C.E.T) test after 2 hours immersion in boiling water (98 ± 2 ℃) Navigator Confirmation of coating appearance after 2 hours immersion in boiling water (98 ± 2 ℃) Acceleration Weather Resistance (W ~ O ~ M) Measure color difference and gloss retention of coating after 3000 hours with W ~ O ~ M tester Popping resistance Visual observation judgment Bubble resistance Visual observation judgment

la. Test result

The results of the physical property test by the method of [Table 6] are the same as the contents of [Table 7] and [Table 8] below.

Coating
thickness Test Items Polish
(Gloss
60 °) Coating Hardness
(MEK Rubs) pencil
Hardness Machinability
(T-Bend) Attachment
(CET) Impact resistance
(Impact) Bubble resistance Example 1 50 탆 10-65% 100 ~
110 times F or more 5 points 6 mm
More than Good Good Example 2 50 탆 10-65% 100 ~
110 times F or more 5 points 6 mm
More than Good Good Example 3 50 탆 10-65% 100 ~
110 times F or more 5 points 6 mm
More than Good Good Example 4 50 탆 10-65% 110 ~
120 times F or more 5 points 6 mm
More than Good Good Example 5 50 탆 10-65% 110 ~
120 times F or more 5 points 6 mm
More than Good Good Example 6 50 탆 10-65% 110 ~
120 times F or more 5 points 6 mm
More than Good Good Example 7 50 탆 10-70% 110 ~
120 times F or more 4 points 5 mm
More than Good Good Example 8 50 탆 10-70% 110 ~
120 times F or more 4 points 5 mm
More than Good Good Example 9 50 탆 10-70% 120 times
More than F or more 4 points 5 mm
More than Good Good Comparative Example 1 20 탆 10-60% 100 ~
110 times F 4 points 5 mm
More than Good Good 50 탆 10-30% 100 ~
110 times F 2 points 5 mm
More than Peeling Occur

Film thickness Test Items Acid resistance of mine
Alkaline Navigator
& Adhesive Navigator Popping
(popping) Accelerated weather resistance (W ~ O ~ M) Color retention Chalk resistance Example 1 50 탆 Early and
same Early and
same 100/100 Early and
same Good AE 5 or less Early and
same Example 2 50 탆 Early and
same Early and
same 100/100 Early and
same Good AE 5 or less Early and
same Example 3 50 탆 Early and
same Early and
same 100/100 Early and
same Good AE 5 or less Early and
same Example 4 50 탆 Early and
same Early and
same 100/100 Early and
same Good AE 5 or less Early and
same Example 5 50 탆 Early and
same Early and
same 100/100 Early and
same Good AE 5 or less Early and
same Example 6 50 탆 Early and
same Early and
same 100/100 Early and
same Good AE 5 or less Early and
same Example 7 50 탆 Early and
same Early and
same 100/100 Early and
same Good AE 5 or less Early and
same Example 8 50 탆 Early and
same Early and
same 100/100 Early and
same Good AE 5 or less Early and
same Example 9 50 탆 Early and
same Early and
same 100/100 Early and
same Good AE 5 or less Early and
same Comparative Example 1 20 탆 Early and
same Early and
same 100/100 Early and
same Some occurrence AE 5 or less Early and
same 50 탆 trace trace 50/100 trace Occur AE = 7 Occur

* In the Color Retention test item of accelerated weather resistance, AE 5 or less is good, and AE 5 is bad.

As can be seen from the results as shown in [Table 7] and [Table 8], almost all of the specimens produced in the nine examples were compared with the specimens produced with the coating thickness of 20 μm using the comparative example. The test items showed more than equivalent physical properties, especially in the test items of gloss, pencil hardness, and paping resistance. On the other hand, the specimen prepared using a coating film thickness of 50 μm using the comparative example showed notably poor physical properties in almost all the test items, and had little function as a precoated coating film.

The comparison of the results of the nine examples shows that the properties of pencil hardness, impact resistance, bubble resistance, acid resistance, alkali resistance, boiling water, boiling water & adhesion, paping resistance and accelerated weather resistance are all the same. However, in the case of gloss, Example 7, Example 8 and Example 9 showed better physical properties than other examples, and in the case of coating film hardness, Examples 1, 2 and 3 were carried out. Example 4, Example 5, Example 6, Example 7, and Example 8 also show better physical properties than Example 4, Example 5, Example 6, Example 7, and Example 8 than Example 9 Appeared. On the other hand, in the processability and adhesion test items, Example 1, Example 2, Example 3, Example 4, Example 5 and Example 6 showed superior physical properties than Example 7, Example 8 and Example 9. .

In summary, the results of Example 4, Example 5 and Example 6 can be seen to exhibit a stable excellent physical properties in all the test items compared to the other examples, in particular the case of Example 5 It has been shown to exhibit the physical properties that best match the pursuit of the invention. The test results of these examples show that the hydroxyl value of the highly flexible polyester polyol and caprolactone-modified and urethane-modified polyester-blocking resin described above for the preferred range of use of caprolactone and isophorone diisocyanate, in particular the rate of modification of caprolactone Check the effect on the properties of the coating.

In conclusion, the paint prepared according to the method of the above embodiment according to the present invention is compared with Comparative Example 1, which is a commercially available precoated primer paint commercial product having a relatively thin coating film having a thickness of 20 μm even with a super-thick film having a thickness of 50 μm. With more than equal flexibility, it can control the crack of coating which may occur at corners and bends of steel sheet plastic processing or deep processing, and it has not only equivalent corrosion resistance and impact resistance but also boiling phenomenon of coating film in high temperature baking section. It can be seen that there is no appearance problem due to paping and bubble, etc., and has a relatively superior gloss.

As described above, the caprolactone-modified and urethane-modified polyester block resin and the highly flexible polyester polyol resin mixed composition according to the preferred embodiment of the present invention may be modified through various changes and modifications without departing from the technical spirit of the present invention. Those skilled in the art will appreciate that it is possible to apply to the preparation of thick film type high elastic primers for automotive precoated paints.

Claims (4)

Highly flexible polyester polyol resin and caprolactone-modified and urethane-modified polyester blocked resin mixture composition and method. The dibutyltin oxide of claim 1, wherein 20 to 25 parts by weight of trimethylpropanediol, 18 to 20 parts by weight of neopentyl glycol, 8 to 9 parts by weight of adipic acid, 20 to 25 parts by weight of isophthalic acid, and an ester reaction catalyst are 0.1 to 0.2. It is prepared by diluting 20 to 30 parts by weight of propylene carbonate to a compound which is esterified at a temperature of 200 to 220 ° C. by mixing parts by weight to obtain a hydroxyl value of 225 to 245, a number average molecular weight of 650 to 700, and a weight average molecular weight of 1,100 to 1,300. A highly flexible polyester polyol characterized in that the manufacturing method. The mixture according to claim 1, wherein 1 to 1.5 parts by weight of trimethylolpropane, 3 to 7 parts by weight of caprolactone, and 0.2 to 0.5 parts by weight of dimethylolpropionic acid are mixed in an appropriate equivalent ratio, and synthesized by caprolactone ring opening and addition at 120 ° C. After preparing a diol intermediate having 145 to 150, 7 to 9 parts by weight of cyclohexane dimethanol, 5 to 6 parts by weight of neopentyl glycol, and 15 to 20 parts by weight of dodecanedioic acid were mixed to esterify dehydration condensation at 220 ° C. After the reaction, a caprolactone-modified and urethane-modified polyester composite obtained by urethane-modifying urethane-modified 15-20 parts by weight of isophorone diisocyanate at 90 ° C. was prepared. After mixing by weight parts to block the number average molecular weight of 4,000 ~ 4,500, weight average molecular weight 9, prepared by diluting to 35 to 40 parts by weight of propylene carbonate Caprolactone-modified and urethane-modified polyester block resin and a manufacturing method characterized in that having a 000 ~ 12,000, when the blocked isocyanate is all dissociated has an NCO equivalent of 4,000 ~ 5,000. The mixed resin composition according to claim 1 or 2 or 3, wherein 5 to 10 parts by weight of the highly flexible polyester polyol resin and 90 to 95 parts by weight of the caprolactone-modified and urethane-modified polyester block resin are mixed at room temperature. Manufacturing method.