JP2020203964A - Thermosetting resin composition, cured product and laminate - Google Patents

Abstract

To provide a thermosetting resin composition capable of obtaining a cured film excellent in abrasion resistance, and a method for producing a cured film formed of the composition.SOLUTION: A thermosetting resin composition contains a melamine resin (A) at least a part of which is ethyl-etherified or butyl-etherified, polyol (P) containing low molecular polyol (C) having a hydroxyl value of 150 mgKOH/g or more and a number average molecular weight of 62-800, and at least one curing catalyst (D) selected from the group consisting of a Lewis acid catalyst composed of cation composed of metal having electronegativity of Pauling of 1.61-1.90 and counter anion that is a deprotonation body of a proton acid having an acid dissociation constant pKa of 2.0 or less, and a proton acid having an acid dissociation constant pKa of 2.0 or less, in which the content of the (C) is 30 pts.mass or more with respect to 100 pts.mass of the (P), and a solid content mass ratio (A)/(P) is within a range of 99/1 to 35/65.SELECTED DRAWING: None

Description

The present invention relates to a laminate containing a thermosetting resin composition, a cured product composed of the composition, and a cured film composed of the composition.

Conventionally, thermosetting resin compositions containing polyols and alkyl etherified melamine have been used in various fields such as automobile paints, home appliance paints, and building materials, and the storage stability of the compositions is good. In addition, it is required to have excellent durability and appearance of the obtained cured film. Further, the curing of the thermosetting resin composition requires a heating time of 10 to 60 minutes at a temperature of about 110 to 160 ° C., but from the viewpoint of energy saving, heat that can be cured at a lower temperature and in a shorter time. There is a strong demand for curable resins.

Here, in the cross-linking reaction between the polyol and the alkyl etherified melamine, ether exchange proceeds between the hydroxyl group (A- OH ) of the polyol and the ether group (B- OR ) of the alkyl etherified melamine, and the alkyl etherified melamine The derived alcohol (R-OH) is eliminated. Although this reaction is an equilibrium reaction, cross-linking can proceed irreversibly by volatilizing the desorbed alcohol to the outside of the system, and the conditions for this are a temperature of approximately 110 to 160 ° C. and heating for 10 to 60 minutes. It takes time. A catalyst may be used for the purpose of promoting cross-linking in this cross-linking reaction, and it has been reported that a Lewis acid catalyst is effective in addition to protonic acid.

As the alkyl etherified melamine, methyl etherified melamine (hereinafter referred to as "methylated melamine") and butyl etherified melamine (hereinafter referred to as "butylated melamine") are industrially produced and used. On the other hand, in Patent Document 1, baking of ethyl etherified melamine (hereinafter referred to as "ethylated melamine") resin at 90 to 180 ° C. for 20 to 30 minutes (more specifically, 120 ° C. for 30 minutes). It is disclosed that by curing the polyol under the conditions without a catalyst, a cured film having a better balance between hardness and water resistance can be formed as compared with the case where methylated melamine and butylated melamine are used.

Japanese Unexamined Patent Publication No. 2014-098105

When the present inventors retested the method of Patent Document 1, the obtained cured film had a certain level of solvent resistance and pencil hardness, but its crosslink density was not sufficient and was hard. It turned out that it did not have sufficient abrasion resistance to be called a coat.

Here, it is widely known that a hard coatable cured film having high wear resistance can be obtained extremely easily by using a radiation curable resin such as ultraviolet rays or electron beams as compared with a thermosetting resin. For example, a trifunctional or higher functional (meth) acrylic acid ester oligomer, more specifically, a mixture of trimethylolpropane triacrylate (abbreviated as TMPTA) and pentaerythritol triacrylate / tetraacrylate (abbreviated as PETTA / PETA, respectively). A coating film formed by curing a commercially available oligomer represented by a mixture of dipentaerythritol pentaacrylate / hexaacrylate (abbreviated as DPPA / DPHA, respectively) by irradiating it with ultraviolet rays in the presence of a photoradical initiator. Has high abrasion resistance, and these are used as raw materials for hard coat coatings.

However, these are derived from the curing system, such as the unreacted acrylic group gradually reacting later, which increases the shrinkage stress and eventually causes the coating film to crack, and the components derived from the photoinitiator gradually turn yellow. Due to its weak weather resistance, there is a limit to its application to applications that are always used outdoors, for example. Further, when an electron beam is used for the curing reaction, a photoinitiator is not required, but there is a problem that the electron beam irradiation equipment is large and extremely expensive. Further, there is a problem that it is difficult to adapt to a complicated three-dimensional object because it is not possible to cure a portion that is not directly exposed to radiation, which is common to ultraviolet rays and electron beams.

On the other hand, the cured coating of thermosetting resin based on polymer polyol and alkylated melamine is widely used in applications that are supposed to be used outdoors such as automobiles and building materials, and is compared with ultraviolet curable resin. It has good weather resistance, can be cured regardless of the shape of the adherend, and can be cured only with a drying furnace, which is cheaper than UV / electron beam irradiation equipment, but generally compared to a hard coat made of thermosetting resin. There was a problem that the wear resistance was inferior.

An object of the present invention is to improve the abrasion resistance of a coating film composed of a thermosetting resin composition using a polyol and an alkyl etherified melamine resin to a level that can be used as a hard coat under practical heating conditions. And.

As a result of diligent studies by the inventors to improve the abrasion resistance of the coating film made of a thermosetting resin based on a polyol and an alkyl etherified melamine, at least a part of the melamine resin is ethyl etherified or butyl etherified. A polyol containing a low molecular weight polyol having a hydroxyl value of 150 mgKOH / g or more and a number average molecular weight of 62 to 800 and a specific curing catalyst are included, and the content of the low molecular weight polyol with respect to the entire polyol is in a specific range. It has also been found that a coating film having high wear resistance can be formed by using a thermosetting resin composition in which the total solid content mass ratio of the melamine resin and the polyol is in a specific range.

That is, the present invention includes the following aspects.
[1] With the melamine resin (A) at least partially ethyl etherified or butyl etherified,
A polyol (P) containing a low molecular weight polyol (C) having a hydroxyl value of 150 mgKOH / g or more and a number average molecular weight of 62 to 800,
A Lewis acid catalyst consisting of a proton consisting of a metal having an electronegative degree of Pauling of 1.61 to 1.90 and a counter anion which is a deprotonated product of a protonic acid having an acid dissociation constant pKa of 2.0 or less, and acid dissociation. It contains at least one curing catalyst (D) selected from the group consisting of protonic acids having a constant pKa of 2.0 or less.
The content of the low molecular weight polyol (C) is 30 parts by mass or more with respect to 100 parts by mass of the polyol (P).
A thermosetting resin composition, wherein the total solid content mass ratio (A) / (P) of the melamine resin (A) and the polyol (P) is in the range of 99/1 to 35/65.

[2] The thermosetting resin composition according to Item [1], wherein the low molecular weight polyol (C) contains one or more primary or secondary hydroxyl groups.
[3] The item [1] or [2], wherein the polyol (P) further contains a polymer (B) containing a hydroxyl group and having a weight average molecular weight of 5,000 to 500,000. Thermosetting resin composition.

[4] The content of the catalyst (D) is 0.1 to 5 parts by mass with respect to 100 parts by mass in total of the melamine resin (A), the polymer (B) and the low molecular weight polyol (C). The thermosetting resin composition according to Item [3].

[5] A group consisting of pigments, dyes, leveling agents, adhesion-imparting agents, stability improvers, foaming inhibitors, weather resistance improvers, armpit inhibitors, antioxidants, dispersants, wetting agents, tincture agents and UV absorbers. The thermosetting resin composition according to any one of Items [1] to [4], further comprising at least one additive (E) selected from the above.

[6] A cured product comprising the thermosetting resin composition according to any one of items [1] to [5].
[7] Production of a cured product, which comprises a step of heating the thermosetting resin composition according to any one of Items [1] to [5] to a temperature of 60 to 160 ° C. to cure it. Method.

[8] The method for producing a cured product according to item [7], wherein the heating time in the step is in the range of 20 seconds to 60 minutes.
[9] A laminate comprising a cured film made of the thermosetting resin composition according to any one of Items [1] to [5].

[10] A method for producing a laminate containing a base material and a cured film, wherein the thermosetting resin composition according to any one of items [1] to [5] is applied to the base material to form a coating film. A method for producing a laminate, which comprises a step of forming the coating film and a step of heating the coating film at a temperature of 60 to 160 ° C. for 20 seconds to 60 minutes to form a cured film.

[11] The method for producing a laminate according to Item [10], wherein the base material contains at least one material selected from metal, glass and resin.

According to the present invention, a thermosetting resin composition capable of forming a coating film having excellent durability and appearance and having a hard coat property, a cured product made of the composition, and a cured film made of the composition. A laminate containing the above is provided. Due to its rapid curing, the thermosetting resin composition of the present invention can be applied to applications such as plastic films having insufficient heat resistance, and when a sufficient curing temperature and time are applied, ultraviolet rays are emitted. It is possible to form a cured film having a level of abrasion resistance comparable to that of a curable resin.

It is a figure which approximately compares the distance between the cross-linking points newly formed at the time of curing in various compounds.

First, the contents of the study that led to the completion of the present invention will be described.
Factors that are effective for the abrasion resistance of the cured film include the number of functional groups that contribute to cross-linking in the unit molecule (so-called oligomer, polymer) of the raw material resin of the cured film, the distance between cross-linking points, and the glass transition temperature of the resin that constitutes the coating film. There are various factors such as the presence or absence of reversible bonds such as hydrogen bonds and π-π bonds, and whether a part of the coating film contains a flexible part, but in particular, the number of functional groups contributing to cross-linking and the contribution of the distance between cross-linking points Is generally known to be relatively high.

In order to evaluate the wear resistance, steel wool, wear wheels, cloth, paper, etc. are placed on the paint film and reciprocated on the paint film while applying a constant load, and the haze and gloss before and after the test are applied. A method of quantifying such factors is widely used. For example, Table 1 shows the results of Reference Examples 1 to 3 below for evaluating the abrasion resistance of a cured film made of a commercially available ultraviolet curable resin. Since the acrylic functional group equivalents (which are almost synonymous with the distance between the cross-linking points) of the three compared here are at the same level, it can be seen that the wear resistance is improved in proportion to the number of acrylic functional groups.

[Reference example 1]
A mixture of 5.00 g of Aronix M309 (TMPTA, manufactured by Toa Synthetic Co., Ltd.) and 0.150 g of Irgacure 1173 (manufactured by BASF Japan Ltd.) is mixed with an easily adhesive PET film (Cosmo Shine A4300, Toray Co., Ltd.) with a thickness of 100 μm. ), Painted with bar coater # 10, pass through the UV conveyor once, and irradiate with UV (no electrode H valve 240 W / cm ² , output 100%, lamp height 70 mm, conveyor speed 9.5 m / min, A cured film was prepared by measuring with an integrated light intensity of 400 mJ / cm ² and UV Power Puck II manufactured by Electronic Instrumentation & Technology, Inc.).

Haze of the cured film immediately after curing and steel wool (Bonster No. 0000, Nippon Steel Wool Industry Co., Ltd.) using a Gakushin type wear tester (wear tester type II, manufactured by Yasuda Seiki Seisakusho Co., Ltd.). The haze after 50 reciprocations with a load of 500 g applied from above) was measured with a haze meter (NDH-4000 type, manufactured by Nippon Denshoku Kogyo Co., Ltd.), and an abrasion resistance test was performed.

[Reference example 2]
Change Aronix M309 to Aronix M305 (PETTA / PETA mixture, manufactured by Toagosei Co., Ltd.), add 5.15 g of butyl acetate (manufactured by Junsei Chemical Co., Ltd.), paint with bar coater # 20, and then remove the solvent. Therefore, a cured film was prepared in the same manner as in Reference Example 1 except that it was dried at 80 ° C. for 2 minutes, and an abrasion resistance test was conducted.

[Reference example 3]
A cured film was prepared in the same manner as in Reference Example 2 except that Aronix M305 was changed to Aronix M402 (DPPA / DPHA mixture, manufactured by Toagosei Co., Ltd.), and an abrasion resistance test was conducted.

From this, in order to hard coat the cured film formed by the cross-linking reaction between the polyol and the alkyl etherified melamine, it is important to increase the number of functional groups and shorten the distance between the cross-linking points. ..

Alkyl etherified melamine resins are generally formed by reacting melamine with formaldehyde and alcohol and have functional groups (methylol group and alkyl ether group) that can contribute to cross-linking at up to 6 locations, each of which is a polyol. Not only the condensation with and, but also the self-condensation between the alkyl etherified melamine resins occurs at the same time to form a crosslinked film. In terms of the number of functional groups, this is the same number of functional groups as DPHA, which has extremely high wear resistance.

In order to roughly compare the distances between the newly formed cross-linking points during curing, the number of atoms up to the other new cross-linking point atoms and the number of each atom are based on one of the newly generated cross-linking point atoms. Looking at the number, alkyl etherified melamine has 1 new cross-linking point 4 atoms ahead and 4 new cross-linking points 8 atoms ahead, while DPHA has 2 new cross-linking points 8 atoms ahead, 12 There are three atoms ahead, and the average distance between the cross-linking points is shorter for alkyl etherified melamine (see 1 and 2 in Fig. 1. The atom described as "1" is the starting point of the new cross-linking point. Atoms, and the atoms with large numbers are other cross-linking points. The same shall apply hereinafter). From this, considering only the number of cross-linking points and the cross-linking density, when the cross-linking proceeds only by the self-condensation of alkyl etherified melamine, the cross-linking density can be higher than DPHA, so that a cured film having very wear resistance can be formed. there is a possibility.

However, considering the condensation between the polyol and the alkyl etherified melamine, the distance between the cross-linking points including the polyol side becomes a problem. As the polyol, acrylic polyol polymer and polyester polyol are widely used in fields such as automobile paints, precoated metals, and building materials.

For example, the acrylic polyol polymer contains at least a part of monomers such as 2-hydroxyethyl acrylate (HEA), 2-hydroxyethyl methacrylate (HEMA), and 4-hydroxybutyl acrylate (4HBA) when polymerizing the (meth) acrylic monomer. It is synthesized by introducing a hydroxy group into the polymer using. The shortest distance between hydroxyl groups in a polymer is the portion where hydroxyl group-containing monomers having a small molecular weight are continuously linked. For example, even when considering a partial structure in which three HEA molecules are continuous, the new cross-linking point is There are two locations 12 atoms ahead, which is longer than the self-condensation of alkyl etherified melamine and the cross-linking of DPHA (see 3. in FIG. 1). In addition, acrylic polymers are often copolymerized with monomers that do not have hydroxyl groups in order to balance their physical properties. In that case, the distance between new cross-linking points of hydroxyl groups becomes longer, so wear resistance is improved. It will decrease further.

Further, in the case of polyester polyol as well, it is generally difficult to leave a large amount of hydroxy groups in a narrow range because it is synthesized by dehydration condensation of the polyol and the polycarboxylic acid. For example, considering a polyester consisting of two molecules of ethylene glycol, which is the shortest polyol, and one molecule of oxalic acid, which is the shortest dicarboxylic acid, the new cross-linking point is 9 atoms ahead, which is also the self-condensation of alkyl etherified melamine and the cross-linking of DPHA. It is difficult to shorten the distance in comparison (see 4. in Fig. 1).

From the above, when considering only the distance between the cross-linking points, the wear resistance of the cured film of the polyol and the alkyl etherified melamine basically does not reach a high region unless the system contains a certain amount of alkyl etherified melamine. is expected.

Regarding this, when the effects of the ratio of the polymer polyol and the alkyl etherified melamine and the wear resistance were actually verified in Reference Examples 4 to 15 below, the wear resistance was improved when the amount of the alkyl etherified melamine was large. If it is too much, the result will be worse (see Table 2 below).

The reason is that the triazine ring of the melamine resin has a planar structure, so that the movement is easily constrained when the cross-linking reaction proceeds to some extent, and the distance between the cross-linking points is too long compared to the melamine resin. It is conceivable that the movement of the coating film is doubly fixed by eliminating the part where the stress is released, and the structure is very rigid and brittle.

[Reference example 4]
3.89 g of the ethylated melamine resin solution (A-1) and 32.0 g of Almatex XA573 (B-1) (solid content ratio 20/80) shown below are added to isobutanol / 1-methoxy-2-propanol (hereinafter, "" 30.1 g of a mixed solvent of 50/50 (referred to as "PGM") is added and mixed well, and 5% by mass PGM of aluminum nitrate nineahydrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) as a curing catalyst is added thereto. A mixed solution having a non-volatile content of 20% by mass was obtained by adding 2.72 g of the solution (catalyst amount with respect to the resin solid content: 1 wt%). This mixed solution is coated on an easily adhesive PET film (Cosmo Shine A4300, manufactured by Toyobo Co., Ltd.) with a film thickness of 100 μm with bar coater # 14, and heated at 140 ° C. for 40 seconds in a warm air dryer to obtain a film thickness of about. A cured film of 3 μm was prepared, and an abrasion resistance test was carried out in the same manner as in Reference Example 1. The results are shown in Table 2.

<< Ethylated melamine resin solution (A-1) >>
126 g (1.0 mol) of melamine, 196 g (6.0 mol) of paraformaldehyde with a formalin concentration of 92% by mass, and 276 g (6) of ethanol in a four-necked flask equipped with a stirrer, thermometer, reflux condenser and nitrogen introduction tube. (0.0 mol) was charged and the temperature was raised to the reflux temperature. After the methylolation reaction was carried out at the reflux temperature for 1 hour, 0.180 g (0.53 mmol) of a 50 mass% aqueous solution of paratoluenesulfonic acid (water; SP value = 47.9) was added, and ethyl ether was added under reflux. The chemical reaction was carried out for 3 hours. Then, the reaction product was neutralized with 0.160 g (0.80 mmol) of a 20 mass% sodium hydroxide solution, and then ethanol and water were distilled off under reduced pressure, and then isobutanol (SP value = 23.5). An ethylated melamine resin solution (A-1) was obtained by diluting the mixture until the non-volatile content was 70% by mass. The number average molecular weight of the obtained resin was 900, and the weight average molecular weight was 2,000.

<< Polymer (B-1) >>
Acrylic polyol "Almatex XA573" (manufactured by Mitsui Chemicals, Inc.)
-Solvent: Mixed solvent of n-ethyl acetate and isopropanol-Solid content: 34% by mass
-Solid content hydroxyl value: 200 mgKOH / g
-Solid acid value: 3.9 mgKOH / g
・ Number average molecular weight: 15,000
-Weight average molecular weight: 46,000

[Reference Examples 5 to 15]
The ethylated melamine resin solution (A-1) and Almatex XA573 (B-1) are mixed so that the solid content ratio is 30/70 to 100/0, and the total solid content is 20% by mass accordingly. A cured film was formed in the same manner as in Reference Example 4 except that the amount of the solvent was adjusted as described above, and the abrasion resistance was evaluated. The results are shown in Table 2.

As described above, there is a limit to the improvement of wear resistance due to the content of the melamine resin, and even if the hydroxyl group concentration (hydroxyl value) of the acrylic polyol polymer or polyester polyol is increased in order to increase the crosslink density from the polyol side. , As mentioned above, there are structural limitations.

Therefore, as a result of examining the addition of a low molecular weight polyol having a high hydroxyl value in order to form a coating film having a shorter distance between cross-linking points, a low molecular weight polyol having a hydroxyl value and a number average molecular weight in a specific range was specified. It was found that the wear resistance was improved when mixed in a ratio.

In this study, surprisingly, the hydroxyl value of the low molecular weight polyol is effective from a region lower than that estimated from the consideration of the distance between the cross-linking points, and conversely, ethylene glycol, which is the low molecular weight polyol having the highest hydroxyl value, is effective. It has been clarified that although it is sufficiently effective in improving wear resistance, it is not the most effective. This is because even if the number of hydroxyl groups themselves is not large, the distance between the hydroxyl groups is within an appropriate range, so that the degree of freedom in the movement of the molecular chain is guaranteed during curing and the reaction rate of the hydroxyl groups is improved, resulting in a higher hydroxyl value. The degree of cross-linking is about the same as that of low-molecular-weight polyols that restrict the movement of things, and even if the distance between hydroxyl groups is large, it cannot contribute to the reaction and the number of remaining hydroxyl groups increases, resulting in the formation of dense cross-links. It is presumed that the distance between the hydroxyl values and the reaction rate contribute to this. Further, the present invention was completed by verifying the effective range of the alkyl etherified melamine resin and the catalyst.

Hereinafter, the present invention will be described in detail.
[Thermosetting resin composition]
The thermosetting resin composition of the present invention (hereinafter, also simply referred to as “the composition of the present invention”) is a melamine resin (A) which is at least partially ethyl etherified or butyl etherified, and has a hydroxyl value of 150 mgKOH /. A polymer (P) containing a low molecular weight polyol (C) having a molecular weight of 62 to 800 or more and a metal having an electronegative degree of Pauling of 1.61 to 1.90 and an acid dissociation constant pKa of 2 A Lewis acid catalyst composed of a counter anion which is a deprotonated product of a protonic acid of .0 or less, and at least one curing catalyst (D) selected from the group consisting of a protonic acid having an acid dissociation constant pKa of 2.0 or less. The content of the low molecular weight polyol (C) is 30 parts by mass or more with respect to 100 parts by mass of the polyol (P), and the total solid content of the melamine resin (A) and the polyol (P). The mass ratio (A) / (P) is in the range of 99/1 to 35/65. Details of each component are shown below.

<Melamine resin (A)>
The melamine resin (A) used in the present invention is a melamine resin (the melamine resin refers to a thermosetting resin obtained from melamine and formaldehyde) in which at least a part of the methylol groups is ethyl etherified or butyl ether. Formaldehyde resin.

A preferable example of the melamine resin (A) is the ethylated (ethyl etherified) melamine resin described in Patent Document 1.
Further, as a commercially available product of the melamine resin (A), a butylated (butyl etherified) melamine resin such as "Uban 20SE60" or "Uban 28-60" manufactured by Mitsui Chemicals, Inc. can also be used.

The polystyrene-equivalent weight average molecular weight of the melamine resin (A) measured by GPC (gel permeation chromatography) is preferably 800 to 15,000, more preferably 1,000 to 7,000, and further. It is preferably 1,100 to 5,000. When the weight average molecular weight of the melamine resin (A) is within the above range, a resin composition having an appropriate viscosity can be obtained, and a cured product having excellent mechanical properties, smoothness, appearance and the like can be obtained.

The melamine resin (A) can preferably be obtained by condensing melamine, formaldehyde and an alcohol having an alkyl chain having 1 to 6 carbon atoms in the presence of an acid catalyst, and the alcohol may be at least ethanol or butanol. Used. As a method for producing such a melamine resin (A), the method described in Patent Document 1 can be used. For example, in the case of an ethylened melamine resin, ethanol is used as the alcohol, but as the ethanol, hydrous ethanol may be used, or so-called mixed ethanol containing a small amount of another alcohol such as methanol or isopropanol is used. May be good. Further, in the case of the butylated melamine resin, n-butanol and isobutanol are widely used, but some s-butanol and t-butanol may be contained.

The melamine is not particularly limited, and may be synthesized by a conventionally known method or a commercially available product. The formaldehyde may be an aqueous solution or a solid paraformaldehyde. From the viewpoint of economy, paraformaldehyde having a formalin concentration of 80% or more is preferable.

The total solid content mass ratio (A) / (P) of the melamine resin (A) and the polyol (P) described later with respect to the total amount of the composition of the present invention is 99 / 1-35 / 65, preferably 95 / 5-40. / 60, more preferably 90/10 to 60/40. When the content ratio of the melamine resin (A) is within the above range, a coating film having an excellent balance between abrasion resistance and appearance can be obtained.

<Polyprethane (P)>
The polyol (P) used in the present invention contains a low molecular weight polyol (C) having a hydroxyl value of 150 mgKOH / g or more and a number average molecular weight of 62 to 800, all of which may be low molecular weight polyols (C). However, the low molecular weight polyol (C) and other polyols may be contained.

The content of the low molecular weight polyol (C) is 30 parts by mass or more and 100 parts by mass or less, preferably 50 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the polyol (P). When the content ratio of the low molecular weight polyol (C) is within the above range, a coating film having excellent coatability and abrasion resistance can be obtained.

The polyol other than the low molecular weight polyol (C) is not particularly limited, but a polymer (B) containing a hydroxyl group and having a weight average molecular weight of 5,000 to 500,000 is preferable. The polyol (P) may contain a polyol other than the polymer (B) and the low molecular weight polyol (C) as long as the effects of the present invention are not impaired.

<Polymer (B)>
The polymer (B) used in the present invention is not particularly limited as long as the effects of the present invention are not impaired, and examples thereof include acrylic resin, polyester resin, epoxy resin and urethane resin (however, the melamine resin (A). )except for.). These may be used alone or two or more kinds may be used. The polymer (B) preferably has a hydroxyl group or a carbonyl group from the viewpoint of compatibility with the low molecular weight polyol (C) and improvement of abrasion resistance of the coating film, and an acrylic resin having both a hydroxyl group and a carbonyl group and a hydroxyl group and a carbonyl group. A polyester resin having both groups is more preferable.

The hydroxyl value of the polymer (B) is preferably 30 to 250 mgKOH / g, more preferably 40 to 200 mgKOH / g (solid content). When the hydroxyl value is within the above range, the crosslink density of the coating film is high, the strength and hardness of the coating film are sufficient, and the impact resistance and appearance are good.

The polymer (B) has a polystyrene-equivalent weight average molecular weight (Mw) measured by GPC, usually 5,000 to 500,000, preferably 10,000 to 200,000, and more preferably 20,000. ~ 150,000. When the Mw of the polymer (B) is within the above range, the coating property, the appearance of the coating film, the strength, the hardness, the abrasion resistance and the like are excellent.

Examples of commercially available polymers of the polymer (B) include those having a hydroxyl group, "Cotax LH-601" manufactured by Toray Fine Chemicals Co., Ltd., "Cotax LH-591" manufactured by Mitsui Chemicals Co., Ltd. Examples thereof include "Almatex P646", "Almatex XA573", "Almatex L1057", "Olestar Q164", "Olestar Q810", and "Olestar Q519".

<Low molecular weight polyol (C)>
The low molecular weight polyol (C) used in the present invention has a hydroxyl value of 150 mgKOH / g or more and a number average molecular weight of 62 to 800.

The hydroxyl value of the low molecular weight polyol (C) is preferably 180 to 4128 mgKOH / g, more preferably 250 to 2500 mgKOH / g, and even more preferably 300 to 1900 mgKOH / g.

The number average molecular weight of the low molecular weight polyol (C) is preferably 62 to 600, more preferably 80 to 400, and even more preferably 90 to 300.
From the viewpoint of reactivity, the low molecular weight polyol (C) preferably contains one or more primary or secondary hydroxyl groups, and particularly preferably contains two or more primary hydroxyl groups.

The low molecular weight polyol (C) is not particularly limited as long as it satisfies the above-mentioned requirements for hydroxyl value and number average molecular weight, and is, for example, ethylene glycol, propylene glycol, 1,6-hexanediol, and 2,5-hexane. Diol, 3-methyl-1,5-pentanediol, neopentyl glycol, 2-methyl-1,5-pentanediol, 2,2-diethyl-1,3-propanediol, 1,2-butanediol, 1, Aliphatic diols such as 3-butanediol, 1,4-butanediol 1,9-nonanediol, 1,10-decanediol, butylethylpropanediol, and butylethylpentanediol; fats such as 1,4-cyclohexanedimethanol. Cyclic diols; aliphatic polyols such as trimethylolpropane, glycerin, pentaerythritol, ditrimethylolpropane, dipentaerythritol; saccharides such as glucose, sculose and amylose; bisphenol compounds; Polyether polyols; examples include polycarbonate diols and polyester polyols.

<Polymer (b)>
The composition of the present invention may contain a polymer (b) other than the melamine resin (A) and the polyol (P), if necessary. For example, a polymer having no hydroxyl group and having a weight average molecular weight of 5,000 to 500,000 (eg, “Almatex 1044” manufactured by Mitsui Chemicals, Inc.) can be mentioned.

<Curing catalyst (D)>
The curing catalyst (D) used in the present invention (hereinafter, also simply referred to as “catalyst (D)”) is a cation composed of a metal having an electronegative degree of Pauling of 1.61 to 1.90, and an acid dissociation constant pKa. A Lewis acid catalyst composed of a counter anion which is a deprotonated product of a protonic acid having an acid dissociation constant of 2.0 or less, and at least one curing catalyst selected from the group consisting of a protonic acid having an acid dissociation constant pKa of 2.0 or less. is there. For pKa, refer to the values described in Kagaku-Dojin Bruce Organic Chemistry 4th Edition and JP Cuthrie, Can. J. Chem. 1978, 56, 2342-2354.

Examples of metals having Pauling's electronegativity of 1.61 to 1.90 include aluminum, vanadium, chromium, iron, cobalt, zinc and copper. Among these, aluminum, zinc, cobalt and copper are preferable, and aluminum and copper are particularly preferable in terms of curing speed. When the resin system is an aqueous dispersion system, a Lewis acid catalyst composed of an inorganic salt may act as a flocculant, but copper and cobalt are preferable because they do not easily coagulate the resin.

Protonic acids (breasted acids) having an acid dissociation constant pKa of 2.0 or less include inorganic acids such as nitrate, sulfuric acid, hydrochloric acid, hydrobromic acid and phosphoric acid, and organic acids such as methanesulfonic acid and paratoluenesulfonic acid. Can be mentioned.

The Lewis acid catalyst is preferably at least one selected from the group consisting of nitrates, sulfates and halides, and nitrates are particularly preferable from the viewpoint of availability and solubility. Specific examples of the Lewis acid catalyst include aluminum nitrate, zinc nitrate, cobalt nitrate, copper nitrate and hydrates thereof.
Inorganic protonic acid is particularly preferable from the viewpoint of price, but Lewis acid salt is preferable from the viewpoint of safety in handling by workers and less damage to piping of painting equipment.

The content of the catalyst (D) is preferably 0.1 to 5% by mass with respect to 100 parts by mass of the total solid content of the melamine resin (A), the polymer (B) and the low molecular weight polyol (C). Parts, more preferably 0.25 to 3 parts by mass, particularly preferably 0.5 to 2 parts by mass. When the content of the catalyst (D) is within the above range, a thermosetting resin composition having excellent storage stability and curability can be obtained.

<Additive (E)>
The composition of the present invention may contain an additive (E), if necessary. Such additives are not particularly limited as long as the effects of the present invention are not impaired, and known additives can be used. Specifically, pigments, dyes, leveling agents, adhesion-imparting agents, stability improvers, foaming inhibitors, weather resistance improvers, armpit inhibitors, antioxidants, dispersants, wetting agents, tincture agents, UV absorbers, etc. Can be mentioned. The additive (E) may contain a Lewis acid and a protonic acid that do not fall into the category of the catalyst (D). Further, the additive (E) may be used alone or in combination of two or more.

The content of the additive (E) with respect to 100 parts by mass of the total amount of the composition of the present invention is usually 0 to 50 parts by mass, preferably 0 to 30 parts by mass. When the content of the additive (E) is within the above range, a thermosetting resin composition having excellent coatability, coating film physical properties and storage stability can be obtained.

<Solvent>
The composition of the present invention may contain a solvent, if necessary. The solvent is not particularly limited as long as the effect of the present invention is not impaired, and examples thereof include alkylbenzene-based solvents such as benzene, toluene and xylene, and acetate-based solvents such as ethyl acetate, propyl acetate, butyl acetate, amyl acetate and methyl acetoacetate. Ketone solvents such as dioxane, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, alcohol solvents such as methanol, ethanol, isopropanol, 1-butanol, 2-butanol, isobutanol, 1-methoxy-2-propanol (PGM), And water and the like. The solvent may be used alone or in combination of two or more.

Since the composition of the present invention contains a low molecular weight polyol (C), it is preferable that at least a part of the solvent contains an alcohol solvent or water from the viewpoint of compatibility. Further, a solvent having a boiling point exceeding 200 ° C. is not preferable because it has poor drying property and lowers the reaction rate.

The total content of the solvent with respect to the total amount of the composition of the present invention is preferably 10 to 95% by mass, more preferably 20.0 to 90.0% by mass, and further preferably 50.0 to 85.0% by mass. ..

[Cured product and laminate]
The cured product of the present invention is characterized by comprising the composition of the present invention, and is usually in the form of a cured film. Further, the laminate of the present invention is characterized by containing a cured film made of the composition of the present invention.

The method for producing a cured product (cured film) of the present invention is a step of heating the composition of the present invention to a temperature of 60 to 160 ° C., preferably 70 to 140 ° C. to cure it (hereinafter, also referred to as “heating step”). It is characterized by including.

The heating time in the heating step is in the range of 20 seconds to 60 minutes, preferably in the range of 30 seconds to 40 minutes, depending on the heating temperature, and the heat resistance of the base material (object to be coated) and the productivity of the coating line. The temperature and time can be combined appropriately according to the conditions.

The composition of the present invention can be suitably used for paint (coating material) applications. That is, after the composition of the present invention is applied to a base material (object to be coated) to form a coating film, the coating film is heated (dried) under the same conditions as in the heating step to form a cured film. Therefore, the laminate of the present invention can be produced.

The heating may be performed in two or more steps, and a post-curing step such as moving the laminate cured within the temperature and time range described above to another heat insulating chamber and heating it separately may be performed. The heating step may be performed under reduced pressure or under an inert gas atmosphere or the like.

Since the composition of the present invention has a high reaction rate and can form a cured film having good wear resistance even at a relatively low temperature, not only can energy saving be achieved by lowering the heating temperature, but also curing can be completed in a short time at a high temperature. Because it can also be done, excellent productivity can be achieved. By using the composition of the present invention having such characteristics, curing can be completed before the heat-sensitive base material (painted body) such as plastic is softened. Therefore, the base material (painted body) is applied. The range can be extended.

The base material (object to be coated) preferably contains at least one material selected from metal, glass and resin. For example, metal materials include iron, aluminum, zinc, stainless steel, and those surface-treated, and resin materials include vinyl chloride, polyethylene terephthalate, polyethylene, polypropylene, polycarbonate, ABS, PMMA, nylon, and the like. Examples thereof include polyamides and those which have been surface-treated. Further, a substrate made of these materials coated with a primer, an intermediate coating, or a top coating coating can also be used, if necessary.

As described above, since the present invention can be cured at a low temperature and in a short time, thermal deformation of the base material can be suppressed. That is, in the present invention, since a base material having inferior heat resistance can be used, various base materials can be selected according to a desired application.

The method for applying the composition of the present invention to the substrate is not particularly limited, and is a spray coating method, a dip coating method, a roll coating method, a gravure coating method, a spin coating method, and a method using a bar coater or a doctor blade. Etc.,
The thickness of the cured film is not particularly limited and may be appropriately selected depending on the desired application, but is preferably 0.05 to 40 μm, more preferably 0.1 to 30 μm.

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples, but the present invention is not limited to these Examples.
[Physical properties]
The methods for measuring the physical properties of the materials used in the examples and comparative examples are as follows.

<Number average molecular weight and weight average molecular weight>
The number average molecular weight and weight average molecular weight of the melamine resin (A), the polymer (B) and the polymer (b) were measured by GPC under the following conditions.
Equipment: Showa Denko Corporation Shodex GPC-101
Detector: RI-71S
Column: Showa Denko Co., Ltd. GPC KF804L (Φ8.0 mm x 300 mm) x 3 Measurement temperature: 40 ° C
Eluent: THF (tetrahydrofuran)
Flow velocity: 1.0 ml / min

<Hydroxy group value>
The hydroxyl value of the polymer (B) refers to a value measured according to JIS K 1557-1 (how to obtain the hydroxyl value). However, for the low molecular weight polyol (C), the calculated value calculated from the molecular formula and the molecular weight was used.

[material]
In the examples and comparative examples, the raw materials used when preparing the composition (coating material) and the base materials used when applying the composition are as follows.

<Melamine resin (A)>
(A-1) Ethylated melamine resin solution: As described in Reference Example 4 ・ Solvent: Isobutanol ・ Solid content: 70% by mass
-Number average molecular weight: 900
-Weight average molecular weight: 2,000
(A-2) Butylated melamine resin: "Uban 20SE60" (manufactured by Mitsui Chemicals, Inc.)
-Solvent: mixed solvent of xylene / n-butanol = 40/60 (mass ratio) -Solid content: 60% by mass
-Number average molecular weight: 1,200
-Weight average molecular weight: 3,900

<Polymer (B)>
(B-1) Acrylic polyol: "ALMATEX XA573" (manufactured by Mitsui Chemicals, Inc.)
-Solvent: A mixed solvent of n-ethyl acetate and isopropanol-Solid content: 34% by mass
-Solid content hydroxyl value: 200 mgKOH / g
-Solid acid value: 3.9 mgKOH / g
・ Number average molecular weight: 15,000
-Weight average molecular weight: 46,000
<Polymer (b)>
(B-2) Acrylic polymer: "Almatex 1044" (manufactured by Mitsui Chemicals, Inc.)
・ Solvent: Toluene ・ Solid content: 50% by mass
・ Solid content hydroxyl value: None ・ Solid content acid value: less than 1 mgKOH / g ・ Number average molecular weight: 31,000
-Weight average molecular weight: 59,000

<Low molecular weight polyol (C) and polyol (C')>
The low molecular weight polyol (C) shown in Table 3 below and the polyol (C') not included in the category of the low molecular weight polyol (C) in the present invention were used.

In Table 3, polyethylene glycol 300 (PEG300), polyethylene glycol 600 (PEG600), glycerin (GLY), ethylene glycol (EG), polypropylene glycol 300 (triol type) (PPG300T), and polyethylene glycol which is a polyol (C'). 1000 (PEG1000) is manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.
1,6-Hexanediol (1,6-HD), 2,5-hexanediol (2,5-HD), and trimethylolpropane (TMP) are manufactured by Tokyo Chemical Industry Co., Ltd.
As polypropylene glycol 400 (D-400), ACTCALL D-400 (manufactured by Mitsui Chemicals SKC Polyurethane Co., Ltd.) was used.

<Catalyst (D)>
For all of the Lewis acids, those manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. were used as they were. Proton acids were used after diluting raw materials manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. with PGM in a 5% by mass solution.

As the catalyst (D') not included in the category of the catalyst (D) of the present invention, magnesium nitrate hexahydrate, manganese nitrate hexahydrate, nickel nitrate hexahydrate, bis (ethylacetoacetate) Aluminum and acetic acid (2,4-pentanedionato) were also examined. The physical properties of these catalysts are shown in Table 4.

<Base material>
-Easy-adhesive PET film: Cosmo Shine A4300 (Toyobo Co., Ltd., 210 mm x 297 mm x thickness 100 μm)
-SUS304: JIS, G, 4305 (manufactured by Test Piece Co., Ltd., 150 mm x 70 mm x thickness 2 mm)
-Polycarbonate resin plate: PC1600 (manufactured by Takiron Co., Ltd., 100 mm x 100 mm x thickness 2.0 mm)
-Glass plate: Blue plate glass (manufactured by Test Piece Co., Ltd., 150 mm x 100 mm x thickness 2.0 mm)

[Evaluation items and evaluation methods]
The evaluation of the coating films prepared in Examples and Comparative Examples was carried out as follows.

<Abrasion resistance test>
The method described in Reference Example 1 was used.

<Pencil hardness>
According to JIS K 5600-5-4, apply the pencil lead at an angle of about 45 ° to the test coat surface, and press it strongly against the test coat surface so that the lead does not break, and press it forward at a uniform speed of about 10 mm. I moved it. The hardness symbol of the hardest pencil that did not cause scratches on the coating film was defined as the pencil hardness.

<Adhesion test>
A grid peeling test was conducted in accordance with JIS K 5600-5-6.

[Examples 1-32, Comparative Examples 1-7]
Almatex XA573 (B-1) and a 30% by mass PGM solution of each low molecular weight polyol (C) or (C') were added to 75 parts by mass of the solid content of the ethylened melamine resin solution (A-1). The total solid content of both is 25 parts by mass, and the ratio of the solid content of the component (C) or (C') to 100% by mass of the total solid content of both is the ratio shown in Table 5. The mixture was mixed, and a mixed solvent of isobutanol / PGM = 50/50 (mass ratio) was added to sufficiently dissolve and mix. Next, a 5% by mass PGM solution of aluminum nitrate hexahydrate was used as the catalyst (D), and the total solid content of the component (A-1), the component (B-1) and the component (C) or (C') was 100% by mass. Aluminum nitrate hexahydrate was added so as to be 1 part by mass with respect to the part. The amount of the solvent was appropriately changed and blended so that the non-volatile content of the finally obtained thermosetting resin composition was 20% by mass. The obtained composition was coated on an easily adhesive PET film (Cosmo Shine A4300) having a film thickness of 100 μm with a bar coater # 14, and heated at 140 ° C. for 40 seconds in a warm air dryer to obtain a cured film having a film thickness of about 3 μm. Was prepared, and an abrasion resistance test was carried out in the same manner as in Reference Example 4. The results are shown in Table 5.

[Examples 33 to 40, Comparative Examples 8 to 12]
10.7 g of ethylened melamine resin solution (A-1), 0.735 g of Almatex XA573 (B-1), and 7.50 g of 30% PGM solution of trimethylolpropane (TMP) as low molecular weight polyol (C). A solid content mass ratio of 75 / 2.5 / 22.5) was added, and 29.6 g of a mixed solvent of isobutanol / PGM = 50/50 was added to sufficiently dissolve and mix. Next, 2.00 g of a 5% by mass PGM solution of each catalyst (D) to (D') (1 with respect to 100 parts by mass of the total solid content of the components (A-1), (B-1) and (C)). By mass), a thermosetting resin composition having a non-volatile content of 20% by mass was prepared. The obtained composition is coated on an easily adhesive PET film (Cosmo Shine A4300) having a film thickness of 100 μm with bar coater # 14, and heated at 140 ° C. for 40 seconds or 120 seconds in a warm air dryer to form a film. A cured film having a thickness of about 3 μm was prepared, and an abrasion resistance test was carried out in the same manner as in Reference Example 4. The results are shown in Table 6.

[Examples 41 to 44, Comparative Examples 13 to 24]
10.7 g of ethylened melamine resin solution (A-1) and 7.35 g of Almatex XA573 (B-1) (mass ratio of solid content 75/25) are blended, and isobutanol / PGM = 50/50 (mass ratio). ) Was added (30.4 g) and sufficiently dissolved and mixed. Next, 2.00 g of a 5 mass% PGM solution of each catalyst (D) (1 part by mass with respect to 100 parts by mass of the total solid content of (A-1) and (B-1)) was added, and 20 mass by mass of the non-volatile content was added. It was blended so as to be a thermosetting resin composition of%. The obtained composition is coated on an easily adhesive PET film (Cosmo Shine A4300) having a film thickness of 100 μm with bar coater # 14, and heated at 140 ° C. for 40 seconds or 120 seconds in a warm air dryer to form a film. A cured film having a thickness of about 3 μm was prepared, and an abrasion resistance test was carried out in the same manner as in Reference Example 4. The results are shown in Table 6.

[Examples 45 to 46]
Various melamine resins (A), polymer (B) or polymer (b), and 30% by mass PGM solution of TMP (mass ratio of solid content 75 / 2.5 / 22.5) as a low molecular weight polyol (C). Was blended, a mixed solvent of isobutanol / PGM = 50/50 (mass ratio) was added, and the mixture was sufficiently dissolved and mixed. Next, a 5% by mass PGM solution of aluminum nitrate hexahydrate as the catalyst (D) was added to 1 part by mass with respect to 100 parts by mass of the total solid content of the components (A), (B) and (C). Was added. The amount of the solvent was appropriately changed and blended so that the non-volatile content of the finally obtained thermosetting resin composition was 20% by mass. The obtained composition was coated on an easily adhesive PET film (Cosmo Shine A4300) having a film thickness of 100 μm with bar coater # 14, and heated at 140 ° C. for 40 seconds in a warm air dryer to obtain a film thickness of about 3 μm. A cured film of No. 4 was prepared, and an abrasion resistance test was carried out in the same manner as in Reference Example 4. The results are shown in Table 7.

[Comparative Examples 25 to 26]
10.7 g of various melamine resins (A) and 7.35 g of polymer (B) or polymer (b) (mass ratio of solid content 75/25) are blended, and isobutanol / PGM = 50/50 (mass ratio). 30.4 g of the mixed solvent of the above was added and sufficiently dissolved and mixed. Next, 2.00 g of a 5% by mass PGM solution of each catalyst (D) (1 part by mass with respect to 100 parts by mass of the total solid content of the components (A-1) and (B-1)) was added, and the non-volatile content was 20. It was blended so as to be a thermosetting resin composition of mass%. The obtained composition was coated on an easily adhesive PET film (Cosmo Shine A4300) having a film thickness of 100 μm with bar coater # 14, and heated at 140 ° C. for 40 seconds in a warm air dryer to obtain a film thickness of about 3 μm. A cured film of No. 4 was prepared, and an abrasion resistance test was carried out in the same manner as in Reference Example 4. The results are shown in Table 7.

[Examples 47 to 48]
10.7 g of ethylened melamine resin solution (A-1), 0.735 g of Almatex XA573 (B-1), and 7.50 g of 30 mass% PGM solution of TMP as low molecular weight polyol (C) (mass of solid content). A ratio of 75 / 2.5 / 22.5) was added, and 29.6 g of a mixed solvent of isobutanol / PGM = 50/50 (mass ratio) was added and sufficiently dissolved and mixed. Next, 2.00 g of a 5 mass% PGM solution of aluminum nitrate nine hydrate as a catalyst (D) (1 with respect to 100 parts by mass of the total solid content of the components (A-1), (B-1) and (C) By mass) was added to prepare a thermosetting resin composition having a non-volatile content of 20% by mass. The obtained composition was coated on SUS304 or a glass plate with a bar coater # 50, and heated in a warm air dryer at 140 ° C. for 30 minutes to prepare a cured film having a film thickness of about 10 μm. The abrasion resistance test was carried out in the same manner as in No. 4, and the pencil hardness was measured. The results are shown in Table 8.

[Comparative Examples 27 to 28]
10.7 g of ethylened melamine resin solution (A-1) and 7.35 g of Almatex XA573 (B-1) (mass ratio of solid content 75/25) are blended, and isobutanol / PGM = 50/50 (mass ratio). ) Was added in an amount of 30.4 g, and the mixture was sufficiently dissolved and mixed. Next, 2.00 g of a 5% by mass PGM solution of aluminum nitrate hexahydrate as a catalyst (D) (with respect to 100 parts by mass of the total solid content of the components (A-1), (B-1) and (C)). 1 part by mass) was added, and the mixture was blended so as to obtain a thermosetting resin composition having a non-volatile content of 20% by mass. The obtained composition was coated on SUS304 or a glass plate with a bar coater # 50, and heated in a warm air dryer at 140 ° C. for 30 minutes to prepare a cured film having a film thickness of about 10 μm. The abrasion resistance test was carried out in the same manner as in No. 4, and the pencil hardness was measured. The results are shown in Table 8.

[Example 49]
10.7 g of ethylened melamine resin solution (A-1), 0.735 g of Almatex XA573 (B-1), and 7.50 g of 30 mass% PGM solution of TMP as a low molecular weight polyol (mass ratio of solid content 75 /). 2.5 / 22.5) is blended, and 10.0 g of a 10% by mass PGM solution (component (A-1)) of Beneviol NL1030B (manufactured by Mitsubishi Chemical Corporation, polycarbonate diol, molecular weight 1000) is further blended as an adhesion imparting material. , (B-1) and (C) add 10 parts by mass with respect to 100 parts by mass of the total solid content, and further add 24.5 g of a mixed solvent of isobutanol / PGM = 50/50 (mass ratio). Was dissolved and mixed in. Next, as a catalyst (D), 2.00 g of a 5 mass% PGM solution of aluminum nitrate nine hydrate (1 with respect to 100 parts by mass of the total solid content of the components (A-1), (B-1) and (C)). By mass) was added to prepare a thermosetting resin composition having a non-volatile content of 20% by mass. The obtained composition was coated on a polycarbonate (PC) plate with a bar coater # 50, and heated in a warm air dryer at 110 ° C. for 30 minutes to prepare a cured film having a film thickness of about 10 μm. An abrasion resistance test was carried out in the same manner as in Example 4, the pencil hardness was measured, and the adhesion was further evaluated. The results are shown in Table 9. The adhesion imparting material "Beneviol NL1030B" used in this example is not included in the category of polymer (B) and low molecular weight polyol (C), but is included in the category of polyol (P).

[Comparative Example 29]
In Comparative Example 27, a cured film was prepared in the same manner except that the base material was changed to a polycarbonate (PC) plate and heating was performed at 110 ° C. for 30 minutes, and an abrasion resistance test was performed in the same manner as in Reference Example 4. Was carried out, the pencil hardness was measured, and the adhesion was further evaluated. The results are shown in Table 9.

Claims (11)

A melamine resin (A) that is at least partially ethyl etherified or butyl etherified, and
A polyol (P) containing a low molecular weight polyol (C) having a hydroxyl value of 150 mgKOH / g or more and a number average molecular weight of 62 to 800,
A Lewis acid catalyst consisting of a cation consisting of a metal having an electronegative degree of Pauling of 1.61 to 1.90 and a counter anion which is a deprotonated product of a protonic acid having an acid dissociation constant pKa of 2.0 or less, and acid dissociation. It contains at least one curing catalyst (D) selected from the group consisting of protonic acids having a constant pKa of 2.0 or less.
The content of the low molecular weight polyol (C) is 30 parts by mass or more with respect to 100 parts by mass of the polyol (P).
A thermosetting resin composition, wherein the total solid content mass ratio (A) / (P) of the melamine resin (A) and the polyol (P) is in the range of 99/1 to 35/65. The thermosetting resin composition according to claim 1, wherein the low molecular weight polyol (C) contains one or more primary or secondary hydroxyl groups. The thermosetting resin composition according to claim 1 or 2, wherein the polyol (P) further contains a polymer (B) containing a hydroxyl group and having a weight average molecular weight of 5,000 to 500,000. .. The content of the catalyst (D) is 0.1 to 5 parts by mass with respect to 100 parts by mass in total of the melamine resin (A), the polymer (B) and the low molecular weight polyol (C). The thermosetting resin composition according to claim 3. Selected from the group consisting of pigments, dyes, leveling agents, adhesion-imparting materials, stability improvers, foaming inhibitors, weather resistance improvers, armpit inhibitors, antioxidants, dispersants, wetting agents, tincture agents and UV absorbers. The thermosetting resin composition according to any one of claims 1 to 4, further comprising at least one additive (E). A cured product comprising the thermosetting resin composition according to any one of claims 1 to 5. A method for producing a cured product, which comprises a step of heating the thermosetting resin composition according to any one of claims 1 to 5 to a temperature of 60 to 160 ° C. to cure the thermosetting resin composition. The method for producing a cured product according to claim 7, wherein the heating time in the step is in the range of 20 seconds to 60 minutes. A laminate comprising a cured film made of the thermosetting resin composition according to any one of claims 1 to 5. A method for producing a laminate containing a base material and a cured film, wherein the thermosetting resin composition according to any one of claims 1 to 5 is applied to the base material to form a coating film. A method for producing a laminate, which comprises a step of heating the coating film at a temperature of 60 to 160 ° C. for 20 seconds to 60 minutes to form a cured film. The method for producing a laminate according to claim 10, wherein the base material contains at least one material selected from metal, glass, and resin.

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