JP7553364B2 - Coating composition, component, and railroad vehicle - Google Patents

Description

The present invention relates to an unsaturated polyester-based putty resin composition that can be used for coatings on railway vehicles, etc., and that has excellent workability and can suppress swelling that occurs in coatings under high humidity conditions, as well as to members and railway vehicles that use the same.

Unsaturated polyester resins are generally relatively inexpensive compared to other resins, and have excellent workability as they harden in a short time even at room temperature. In addition, depending on the main raw material selected, they can have a variety of excellent physical and chemical properties. Due to their hardening, drying, polishing, adhesion, etc., they are widely used in a variety of applications, including painting railway cars, repair putty paints for cars, woodworking paints, moldings, and sealants.

The unsaturated polyester resin compositions used in these applications are required to have the following performance characteristics: (1) they can be easily applied in thick layers, they cure quickly at room temperature, and the coating film has excellent curing properties; and (2) they do not crack when the substrate or coating film deforms. The fact that (2) they do not crack is particularly important from the perspective of ensuring the properties of the coating film in the usage environment.

A coating film using a putty composition using such an unsaturated polyester resin composition has the problem that cracks and blisters, which are swellings, occur in the coating film when used for a long time under high humidity conditions. It is known that such blisters occur when moisture from the environment penetrates the putty of the coating film and accumulates inside.

On the other hand, vinyl polymerizable monomers mainly composed of styrene are added to such unsaturated polyester resin compositions as a polymerizable diluent. For example, Patent Document 1 discloses a putty resin composition that contains an unsaturated polyester resin having dicyclopentadiene or a derivative thereof as a condensation component, a hydroxyl value of 15 to 65 mgKOH/g, an acid value of 30 to 65 mgKOH/g, and a styrene mixability of 90% by weight or more.

However, in all of the above resin compositions, a large amount of liquid vinyl polymerizable monomer is added, which reduces the viscosity of the putty, making it difficult to apply thick coats and requiring multiple coats, which tends to lengthen the application time.

On the other hand, in recent years, the railway industry has been demanding a beautiful paint appearance in order to introduce luxury trains and improve corporate image. Furthermore, as blistering progresses, the effectiveness of the paint in protecting the base may decrease. The occurrence of such blisters causes problems such as impairing the aesthetic appearance and base protection, and a solution to this problem is desired. Until now, a putty resin composition that suppresses the occurrence of blisters and has good workability, and a putty obtained by curing this composition have not been available.

Japanese Patent Application Publication No. 10-36766

According to Patent Document 1, the vinyl polymerizable monomer, the main component of which is styrene, is 35 to 75 parts by weight, preferably 40 to 55 parts by weight, per 100 parts by weight of unsaturated polyester resin. If it is less than 35 parts by weight, a coating film with high hardness cannot be obtained, and the putty coating film is easily scratched when polished, and if it exceeds 70 parts by weight, the thickness of the putty coating film deteriorates and the curing property decreases. If the added vinyl polymerizable monomer is hydrophobic, moisture is less likely to penetrate the putty, so adding more of it makes it less likely to cause blisters. On the other hand, if 35 parts by weight of the liquid vinyl polymerizable monomer is added, the viscosity of the putty decreases, so if you try to apply the putty thickly with fewer coats, sagging will occur. In addition, it takes time for the polymerization reaction of the vinyl polymerizable monomer to be completed, which reduces workability.

The object of the present invention is to provide a paint composition, a member having a coating film formed thereon, and a railway vehicle that can reduce the frequency of maintenance and reduce painting workability and costs without compromising design by suppressing the occurrence of blisters and achieving good workability in applying putty.

To achieve the above object, the inventors discovered that by adding a solution of a polymer such as polystyrene dissolved in a liquid vinyl polymerizable monomer to an unsaturated polyester-based putty resin composition, it is possible to suppress the occurrence of blisters and obtain a putty with excellent workability.

That is, in order to achieve the above object, the present invention provides
(A) an unsaturated polyester resin;
(B) a polymerizable unsaturated compound;
(C) a polymerization initiator;
(D) a filler; and
(E) a polymerizable unsaturated compound that is soluble in the polymerizable unsaturated compound.

In order to achieve the above object, the present invention provides a member having a putty layer on a substrate, the putty layer comprising:
(A) an unsaturated polyester resin;
(B) a polymerizable unsaturated compound;
(C) a polymerization initiator;
(D) a filler; and
(E) a polymer that is soluble in a polymerizable unsaturated compound.

Further, in order to achieve the above object, the present invention provides a railroad car having a coating film containing a putty layer, the putty layer comprising:
(A) an unsaturated polyester resin;
(B) a polymerizable unsaturated compound;
(C) a polymerization initiator;
(D) a filler; and
(E) a polymerizable unsaturated compound that is soluble in the polymerizable unsaturated compound.

According to the present invention, a putty can be obtained that can suppress the occurrence of blisters, and that can facilitate application by adjusting the viscosity of the putty resin composition by adjusting the molecular weight and content of polystyrene, thereby shortening the time required for curing to be completed.

The following describes an embodiment of the present invention. The putty resin composition of the embodiment contains the following components (A), (B), (C), (D), and (E). Each component is described below.

<Component (A)>
The component (A) in the embodiment is an unsaturated polyester resin, which includes unsaturated polyester resins of low reactivity to unsaturated polyester resins of high reactivity. Unsaturated polyester is a polycondensate of an unsaturated dibasic acid such as maleic acid or fumaric acid and a polyhydric alcohol such as ethylene glycol or propylene glycol. To make it air-curable, an allyl group can be introduced into the polyester chain, or hexahydrophthalic anhydride can be used as the acid component.

Unsaturated polyester resins themselves are well known and are available from many resin manufacturers for use in FRP, paints, and other applications. There are no particular limitations on the unsaturated polyesters that can be used in the embodiments, so long as they can be used as components of ordinary putties.

For example, various brands such as "UPIKA (registered trademark)" manufactured by Nippon U-Pica Co., Ltd. and "Sandoma (registered trademark)" manufactured by DIC Materials Co., Ltd. can be appropriately selected and used.

The unsaturated polyester resin in the embodiment includes unsaturated polyester resins obtained from polybasic acids or their anhydrides and polyhydric alcohols, as well as unsaturated polyester resins modified with epoxy compounds such as glycidyl methacrylate and bisphenol A type epoxy, and isocyanate compounds such as toluene diisocyanate and isopropenyl-dimethyl-benzyl isocyanate.

<Component (B)>
The component (B) in the embodiment is a polymerizable unsaturated compound, and is a polymerizable unsaturated compound having one or more ethylenically unsaturated groups. Examples of the component include styrene-based monomers such as styrene, methylstyrene, methoxystyrene, and hydroxyethylstyrene, (meth)acrylic monomers such as glycidyl acrylate, glycidyl methacrylate, and dimethylaminoethyl acrylate, (meth)acrylamide-based monomers such as N,N-dimethylacrylamide, N,N-diethylacrylamide, and N-isopropylacrylamide, N-vinylpyrrolidone, N-vinylcaprolactam, N-vinylacetamide, N-acryloylmorpholine, and acrylonitrile. These polymerizable unsaturated compounds may be used alone or in combination of two or more. Among these, styrene, which is particularly hydrophobic and highly versatile, is preferred from the viewpoint of suppressing blistering.

<Component (C)>
In the embodiment, the component (C) is a polymerization initiator, and in order to use the putty resin composition as a putty for various applications, the polymerization initiator (C) is usually blended into the putty resin composition to initiate the reaction between the unsaturated portion of the unsaturated polyester resin (A) and the polymerizable unsaturated compound (B). Examples of the polymerization initiator (C) include a heat curing agent that generates radicals by heat, an ultraviolet curing agent or an electron beam curing agent that generates radicals by active energy rays, etc.

Thermal initiators include organic peroxides, such as known peroxides such as ketone peroxides, diacyl peroxides, dialkyl peroxides, hydroperoxides, peroxy esters, and peroxy ketals.

Examples of UV initiators that can be used include known compounds such as acylphosphine oxides, benzoin ethers, benzophenones, acetophenones, and thioxanthones.

As electron beam initiators, known compounds such as halogenated alkylbenzenes and disulfide compounds are used.

The polymerization initiator of component (C) can be selected from a wide range of options depending on the type of unsaturated polyester used, the desired pot life, and the curing time at temperature. The amount of polymerization initiator added is preferably 0.1 to 6 parts by weight per 100 parts by weight of the putty resin composition. One or a combination of two or more polymerization initiators may be used. The polymerization initiator may be blended in advance with the putty resin composition under non-curing conditions, but is usually blended at the time of use, and it is particularly preferable to blend thermal initiators at the time of use.

<Component (D)>
The component (D) in the embodiment is a filler, and examples of particularly representative ones include calcium carbonate, magnesium carbonate, barium sulfate, mica, talc, kaolin, clay, celite, asbestos, barite, baryta, silica, silica sand, dolomite, limestone, gypsum, aluminum fine powder, hollow balloons, alumina, glass powder, aluminum hydroxide granite, zirconium oxide, antimony trioxide, titanium oxide, molybdenum dioxide, etc. These fillers are selected in consideration of workability, strength, appearance, and economy of the resulting molded product, and calcium carbonate, aluminum hydroxide, silica, talc, etc. are usually used. Surface-treated fillers may also be used.
The amount of the filler (D) is 50 to 250 parts by weight per 100 parts by weight of the total amount of the unsaturated polyester resin (A), the polymerizable unsaturated compound (B), and the polymer (E) soluble in the polymerizable unsaturated compound (B).

<Component (E)>
The component (E) in the embodiment is a polymer that dissolves in the polymerizable unsaturated compound (B). For example, the following polymerizable unsaturated compounds can be exemplified. Examples include styrene-based monomers such as styrene, methylstyrene, methoxystyrene, and hydroxyethylstyrene; (meth)acrylic monomers such as methyl (meth)acrylate, ethyl (meth)acrylate, benzyl (meth)acrylate, glycidyl (meth)acrylate, and dimethylaminoethyl acrylate; (meth)acrylamide-based monomers such as N,N-dimethylacrylamide, N,N-diethylacrylamide, and N-isopropylacrylamide; and polymers such as N-vinylpyrrolidone, N-vinylcaprolactam, N-vinylacetamide, N-acryloylmorpholine, and acrylonitrile. These polymerizable unsaturated compounds may be used alone or in combination of two or more. Among these, polystyrene, which is particularly hydrophobic, is preferred from the viewpoint of suppressing blistering.

Among polystyrenes, syndiotactic polystyrene is more preferred. Polystyrenes include atactic polystyrene, isotactic polystyrene, and syndiotactic polystyrene, which have different three-dimensional structures. When styrene is polymerized into polystyrene in the putty resin composition, it becomes atactic polystyrene, in which the benzene rings are randomly arranged. On the other hand, when it is added as polystyrene, isotactic polystyrene and syndiotactic polystyrene, in which the benzene rings are regularly arranged, can be added. In particular, syndiotactic polystyrene has high crystallinity, so the hydrolysis of the polystyrene itself is extremely low, and blister resistance can be further improved.

The blend ratio of the unsaturated polyester resin (A), the polymerizable unsaturated compound (B), and the polymer that dissolves in the polymerizable unsaturated compound (B) (E) is 20 to 150 parts by weight, and preferably 50 to 120 parts by weight, of the combined amount of components (B) and (E) per 100 parts by weight of component (A). If the combined amount of components (B) and (E) is less than 20 parts by weight, there is a tendency for problems such as a shortage of components necessary for curing, resulting in poor curing. If component (B) exceeds 150 parts by weight, there is a tendency for adhesion to the substrate to decrease significantly.

The ratio of component (B) to component (E) is 4:6 to 9:1 (weight ratio), and preferably 5:5 to 7:3. If the ratio of component (E) is 6 or more, the viscosity becomes too high, the fluidity decreases, and application tends to become difficult. If the ratio of component (E) is less than 1, the viscosity becomes too low, causing frequent dripping, and application of the putty resin composition tends to become difficult.

The putty resin composition of the embodiment may also contain a curing accelerator, a polymerization inhibitor, a colorant, etc. to adjust the curing speed.

Examples of hardening accelerators include metal soaps such as cobalt naphthenate, cobalt octylate, zinc octylate, vanadium octylate, copper naphthenate, and barium naphthenate, metal chelates such as vanadium acetylacetate, cobalt acetylacetate, and iron acetylacetonate, aniline, N,N-dimethylaniline, N,N-diethylaniline, p-toluidine, N,N-dimethyl-p-toluidine, N,N-bis(2-hydroxyethyl)-p-toluidine, 4-(N,N-dimethylamino)benzaldehyde, 4-[N,N-bis(2- Examples of such amines include N,N-substituted anilines such as N,N-bis(hydroxyethyl)aniline, diethanolaniline, N,N-substituted-p-toluidine, and 4-(N,N-substituted amino)benzaldehyde, 4-(N-methyl-N-hydroxyethylamino)benzaldehyde, N,N-bis(2-hydroxypropyl)-p-toluidine, N-ethyl-m-toluidine, triethanolamine, m-toluidine, diethylenetriamine, pyridine, phenylmorpholine, piperidine, N,N-bis(hydroxyethyl)aniline, and diethanolaniline, N,N-substituted-p-toluidine, and 4-(N,N-substituted amino)benzaldehyde.

The amount of the curing accelerator is preferably 0.1 to 5 parts by weight per 100 parts by weight of the total amount of the (A) unsaturated polyester resin and (B) polymerizable unsaturated compound. The curing accelerator may be used alone or in combination of two or more kinds, and may be added to the putty resin composition in advance or added at the time of use.

Examples of polymerization inhibitors include trihydrobenzene, toluhydroquinone, 1,4-naphthoquinone, parabenzoquinone, hydroquinone, benzoquinone, hydroquinone monomethyl ether, p-tert-butylcatechol, and 2,6-di-tert-butyl-4-methylphenol. The amount of polymerization inhibitor is preferably 0.001 to 0.1 parts by weight per 100 parts by weight of the total amount of (A) the unsaturated polyester resin and (B) the polymerizable unsaturated compound.

Representative examples of colorants include inorganic pigments such as titanium white and carbon black, and organic pigments such as phthalocyanine blue and quinacridone red. Various colorants can be used depending on the hue.

The putty resin composition of the embodiment may contain various other additives. For example, viscosity regulators such as viscosity reducers, defoamers, silane coupling agents, air barrier agents such as paraffin, ultraviolet absorbers, plasticizers, aggregates, flame retardants, stabilizers, reinforcing materials, etc. may be contained.

The putty of the embodiment is a cured molded product that contains at least each of the above components (A) to (E) and is cured by any method. When a curing agent is blended into the putty resin composition of the embodiment and cured to obtain a putty, a drying method such as curing by heating or natural drying can be appropriately selected depending on the working time (e.g., drying time) and the thickness of the target substrate, and the drying time and cured state can be adjusted as desired even after applying the putty.

For example, when the outside temperature is low, forced drying (heat drying) can be used, and when the outside temperature is high, natural drying can be used.

The following examples and comparative examples will explain the present invention in more detail. In the following, "parts" refers to parts by weight.
[Preparation of putty resin composition and putty]
[Example 1]

(A) Volatile components were distilled off from unsaturated polyester resin (DH Materials Co., Ltd., Sundoma (registered trademark) CN-703, solid content: approximately 65%) to make the solid content 100%. (B) 15 parts of styrene, an ethylenically unsaturated monomer, (D) 150 parts of talc (Talc SW: Nippon Talc Co., Ltd., particle size: average 12 μm) as a filler, (E) 10 parts of atactic polystyrene (HF77, PS Japan Co., Ltd.) as a polymer that dissolves in the polymerizable unsaturated compound of (B), 2 parts of a cobalt-based accelerator (accelerator RP-136, DIC Co., Ltd.), and 0.5 parts of an amine-based accelerator (reagent: dimethylaniline) were added to 100 parts of the obtained unsaturated polyester resin, and the mixture was stirred for 15 minutes with a high-speed dissolver to obtain a putty resin composition. To 100 parts of the obtained putty resin composition, 1.5 parts of cumene hydroperoxide (Percumyl H-80, manufactured by NOF Corp.) was added as a polymerization initiator (C), and the mixture was thoroughly stirred to obtain a putty resin composition.

The putty resin composition was applied to a thickness of 2 mm using a stainless steel spatula with a thickness of approximately 1 mm on an aluminum plate (A6N01, size: 70 mm x 150 mm x 0.8 mm) attached to a vertically standing panel, and left to harden for 24 hours at 25°C to obtain a putty.

The resulting putty panels were lightly sanded with #400 waterproof paper, spray-painted with "Retan PG80 White Base" (product name, acrylic urethane resin-based topcoat paint, manufactured by Kansai Paint Co., Ltd.) to a dry film thickness of 50 μm, and dried at 25°C for 24 hours to obtain each painted panel. The following evaluation tests were carried out using the resulting putty-coated panels. The results are summarized in Table 1.

(Evaluation of workability)
When the putty resin composition was applied, the tendency of the putty resin composition to drip was evaluated.
○: Little sagging, good formation of 2 mm thickness,
△: There was a lot of dripping, and it was difficult to form a thickness of 2 mm without curing at least once. ×: It was not possible to form a thickness of 2 mm. (Evaluation of adhesion)
The test pieces obtained by the above method were immersed in warm water at 60° C. for 72 hours, and then dried at 40° C. for 24 hours. Thereafter, a cross-cut test was carried out under conditions in accordance with JIS K 5600-5-6, and the adhesion of the coating film was evaluated according to the following criteria.

○: No peeling, ×: Peeling (Evaluation of blister resistance)
The test piece obtained by the above method was immersed in warm water at 85° C., and the surface condition after aging was observed and evaluated according to the following criteria.

S: No blisters after 200 hours, A: No blisters after 100 hours, B: Approximately 10 small blisters after 100 hours, C: Blisters on the entire surface of the test piece after 100 hours [Examples 2 to 10, Comparative Examples 1 to 5]

In Examples 2 to 10 and Comparative Examples 1 to 5, the putty resin composition, putty, and putty-coated plate were obtained in the same manner as in Example 1, except that the unsaturated polyester resin, the type and amount of polymerizable unsaturated compound, the type of filler, and the amount of filler were changed to the formulations shown in Table 2.

The test pieces of the putty obtained were subjected to evaluation tests in accordance with Example 1, and the evaluation results are summarized in Tables 1 and 2.

CN-703: manufactured by DH Material Co., Ltd. CN-705: manufactured by DH Material Co., Ltd. Styrene: manufactured by Showa Denko K.K. Ethyl methacrylate: manufactured by Nippon Shokubai Co., Ltd. Benzyl acrylate: manufactured by Osaka Organic Chemical Industry Co., Ltd. Butyl methacrylate: manufactured by Mitsubishi Gas Chemical Co., Ltd. Percumyl (registered trademark) H-80: manufactured by NOF Corp. Cumene hydroperoxide Niper (registered trademark) BW: manufactured by NOF Corp. Diacyl peroxide talc SW: manufactured by Nippon Talc Co., Ltd. Particle size: average 12 μm
Talc MS: Nippon Talc Co., Ltd., particle size: average 14 μm
Atactic polystyrene: PS Japan Co., Ltd.
Syndiotactic polystyrene: Idemitsu Kosan Co., Ltd.
Polymethyl methacrylate: Asahi Kasei Corporation
From the evaluation results of the above Examples and Comparative Examples, it is understood that in the putty resin composition of the present invention, by containing a polymerizable unsaturated compound and a polymer soluble in the polymerizable unsaturated compound as specific blending parts in the unsaturated polyester-based putty resin composition, the occurrence of blisters can be suppressed and a putty having excellent workability and adhesion can be obtained. In other words, it is possible to provide a putty resin composition that can reduce the frequency of maintenance compared to conventional ones without deteriorating the design, and can reduce painting workability and costs, a putty obtained by curing the putty, and a coating film and a coated body having the putty.

Claims (4)

(A) an unsaturated polyester resin;
(B) a polymerizable unsaturated compound;
(C) a polymerization initiator;
(D) a filler; and
(E) a polymerizable unsaturated compound that is soluble in the polymerizable unsaturated compound,
the combined blending parts of the polymerizable unsaturated compound (B) and the polymerizable unsaturated compound (E) soluble in the polymerizable unsaturated compound are 20 parts by weight or more and less than 150 parts by weight based on 100 parts by weight of the unsaturated polyester resin (A);
The polymerizable unsaturated compound (B) is at least one selected from the group consisting of styrene, methyl methacrylate, benzyl acrylate, and butyl methacrylate,
The polymer that dissolves in the polymerizable unsaturated compound (E) is a syndiotactic polystyrene.
A coating composition comprising: The coating composition according to claim 1,
a weight ratio of the polymerizable unsaturated compound (B) to a polymer soluble in the polymerizable unsaturated compound (E) is 4:6 to 9:1;
A coating composition comprising: A member having a putty layer on a base material,
The putty layer comprises:
(A) an unsaturated polyester resin;
(B) a polymerizable unsaturated compound;
(C) a polymerization initiator;
(D) a filler; and
(E) a polymerizable unsaturated compound that is soluble in the polymerizable unsaturated compound,
the combined blending parts of the polymerizable unsaturated compound (B) and the polymerizable unsaturated compound (E) soluble in the polymerizable unsaturated compound are 20 parts by weight or more and less than 150 parts by weight based on 100 parts by weight of the unsaturated polyester resin (A);
The polymerizable unsaturated compound (B) is at least one selected from the group consisting of styrene, methyl methacrylate, benzyl acrylate, and butyl methacrylate,
The polymer that dissolves in the polymerizable unsaturated compound (E) is a syndiotactic polystyrene.
A component characterized by: A railway vehicle having a coating film containing a putty layer,
The putty layer comprises:
(A) an unsaturated polyester resin;
(B) a polymerizable unsaturated compound;
(C) a polymerization initiator;
(D) a filler; and
(E) a polymerizable unsaturated compound that is soluble in the polymerizable unsaturated compound,
the combined blending parts of the polymerizable unsaturated compound (B) and the polymerizable unsaturated compound (E) soluble in the polymerizable unsaturated compound are 20 parts by weight or more and less than 150 parts by weight based on 100 parts by weight of the unsaturated polyester resin (A);
The polymerizable unsaturated compound (B) is at least one selected from the group consisting of styrene, methyl methacrylate, benzyl acrylate, and butyl methacrylate,
The polymer that dissolves in the polymerizable unsaturated compound (E) is a syndiotactic polystyrene.
A railway vehicle characterized by: