JP2019026770A - Polyamide-imide resin composition, fluorine coating, and conductive composition - Google Patents

Abstract

To provide a polyamide-imide resin composition that contains a solvent that can dissolve a polyamide-imide resin and can improve the work environment, and has excellent storage stability and resists deterioration of its properties.SOLUTION: A polyamide-imide resin composition contains (A) polyamide-imide resin, (B) N-ethyl-2-pyrrolidone, (C) water, and (D) a basic compound, where when it is stored for 7 days at 60°C, a viscosity change rate before and after the storage is within -30%.SELECTED DRAWING: None

Description

  One embodiment of the present disclosure relates to a polyamideimide resin composition. Another embodiment of the present disclosure relates to the use of the polyamideimide resin composition, and more particularly to a fluorine paint containing the polyamideimide resin composition, and a conductive composition.

Polyamideimide resins are widely used in various applications such as coating agents for various substrates because they are excellent in heat resistance, chemical resistance and solvent resistance. For example, a polyamideimide resin is suitably used as a material for enameled wire varnish, heat resistant paint, and the like.
In various applications, a polar solvent such as N-methyl-2-pyrrolidone is generally known as a solvent used for dissolving and diluting a polyamideimide resin and as a solvent used during synthesis. Among these, N-methyl-2-pyrrolidone (NMP) is widely used as a suitable solvent because it can impart excellent solubility to the polyamideimide resin.

  However, in recent years, regulations regarding the use of organic solvents have become stricter from the viewpoint of environmental protection and safety and health. On the other hand, in addition to environmental protection and safety and health, an aqueous resin solution that uses water as a medium instead of an organic solvent has attracted attention from the viewpoints of economy, painting workability, and the like. For example, a method for water-solubilizing a polyamideimide resin in which a basic compound is allowed to act on a carboxyl group remaining at the end of the resin has been reported (Patent Document 1) and applied to various applications.

Japanese Patent No. 3491624

Patent Document 1 clarifies that the amount of NMP used in the resin solution can be reduced by water-solubilizing the polyamideimide resin. However, considering the harmfulness of NMP to the human body, industrial hygiene in the work environment when using NMP is considered a problem in the industry, so the development of water-based polyamideimide resin compositions containing organic solvents other than NMP Is required. That is, there is a demand for an aqueous polyamideimide resin composition using an organic solvent that can dissolve a polyamideimide resin in the same manner as NMP, but has little influence on the human body and can be improved in terms of work environment.
However, the polyamideimide aqueous resin composition obtained by synthesis in an organic solvent other than NMP has a problem of poor storage stability. Therefore, during storage, the polyamideimide resin composition becomes cloudy or the properties of the resin composition are lowered, and it is difficult to obtain desired properties such as adhesion to a metal substrate and mechanical strength.

  Therefore, an embodiment of the present invention provides an aqueous polyamideimide resin composition that includes an organic solvent that can dissolve polyamideimide resin, can be improved in terms of work environment, has excellent storage stability, and has little deterioration in properties. The task is to do.

  The present inventor has found that, in various studies, the polyamideimide resin obtained using an organic solvent other than NMP tends to cause side reactions as compared with the polyamideimide resin obtained using NMP. It has been found that the properties of the resulting polyamideimide resin are likely to deteriorate. In particular, it was found that when N-ethyl-2-pyrrolidone was used during production of the polyamideimide resin, the viscosity of the aqueous composition containing the polyamideimide resin obtained by this reaction tends to decrease during storage. As a cause of viscosity reduction during storage, the reaction between the isocyanate groups tends to proceed during the production of the resin, and the number of bonds between the isocyanate groups in the polyamide-imide resin increases, and the water content contained in the composition includes these bonds. It is thought that it is hydrolyzed by. From these facts, even when an organic solvent other than NMP is used, the present inventors improve the deterioration of characteristics such as storage stability and adhesion by keeping the rate of change in viscosity before and after storage within a certain range. As a result, the present invention has been completed. That is, the embodiment of the present invention relates to the following, but is not limited to the following.

One embodiment includes (A) a polyamideimide resin, (B) N-ethyl-2-pyrrolidone, (C) water, and (D) a basic compound, and changes in viscosity before and after storage at 60 ° C. for 7 days. It is related with the polyamide-imide resin composition whose rate is within -30%.
Other embodiment is related with the fluorine paint containing the polyamide-imide resin composition of the said embodiment, and a fluororesin.
Yet another embodiment relates to a substrate or article having a coating film formed from the fluorine paint of the above-described embodiment on at least a part of its surface.
Yet another embodiment relates to a conductive composition comprising the polyamideimide resin composition of the above embodiment and a conductive material.

  According to the present embodiment, it is possible to provide a water-based polyamide-imide resin composition in which problems in the working environment of the solvent to be contained are reduced, storage stability is excellent, and characteristic deterioration is small. This water-based polyamideimide resin composition can form a coating film excellent in adhesion, and is suitable as a binder for a fluorine paint or a conductive composition.

Hereinafter, preferred embodiments will be described. However, the present invention is not limited to the following embodiments.
1. Polyamideimide resin composition The polyamideimide resin composition is aqueous and includes at least a polyamideimide resin, N-ethyl-2-pyrrolidone, water, and a basic compound. The resin composition is also a heat resistant resin composition. In the present specification, the water-based polyamideimide resin composition may be referred to as “polyamideimide resin composition” or “resin composition”. In addition, “resin composition”, “varnish”, and “paint” may be used in an equivalent sense.
The polyamideimide resin composition preferably has a viscosity change rate of within −30% before and after storage at 60 ° C. for 7 days. When the viscosity change rate is within -30%, deterioration in characteristics after storage is suppressed, and, for example, it is easy to obtain excellent adhesion. The viscosity change rate is more preferably −25% or less. If the viscosity change rate is within the above range, appearance changes such as turbidity of the resin composition hardly occur.
More specifically, the viscosity change rate (%) represents a value calculated from the following (formula 1).
(Formula 1)
Viscosity change rate (%) = (V2−V1) / V1 × 100
In Formula 1, “V1” represents the viscosity of the resin composition measured before storage. “V2” represents the viscosity measured after placing the resin composition in a sealed container and storing the container for 7 days in a drier set at 60 ° C.
The viscosity is measured according to JIS C 2103, using a B-type rotational viscometer under the conditions of 25 ° C., rotor No. 3, and a rotational speed of 12 rpm.

<Polyamideimide resin>
The component (A) polyamideimide resin is a resin obtained by reacting a diisocyanate compound with a tribasic acid anhydride or tribasic acid halide as an acid component. Here, each raw material compound may be used in combination of any plural kinds.

  Although it does not specifically limit as a diisocyanate compound, 4,4'- diphenylmethane diisocyanate, xylylene diisocyanate, 3,3'-diphenylmethane diisocyanate, 3,3'-dimethoxybiphenyl-4,4'-diisocyanate, paraphenylene diisocyanate, hexa Examples include methylene diisocyanate, tolylene diisocyanate, naphthalene diisocyanate, and isophorone diisocyanate. From the viewpoint of reactivity, it is preferable to use 4,4'-diphenylmethane diisocyanate.

  In one embodiment, the polyamideimide resin may partially use a diamine compound in addition to the diisocyanate. Examples of the diamine compound include 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylsulfone, 3,3′-diaminodiphenylsulfone, xylylenediamine, phenylenediamine, and isophoronediamine. Can be mentioned.

  The tribasic acid anhydride is not particularly limited, but an aromatic tribasic acid anhydride is preferably used, and trimellitic acid anhydride is particularly preferable. The tribasic acid halide is not particularly limited, but tribasic acid chloride and further aromatic tribasic acid chloride are preferable, and examples include trimellitic anhydride chloride (trimellitic anhydride chloride). From the viewpoint of reducing the environmental load, it is preferable to use trimellitic anhydride or the like.

As the acid component, in addition to the above-mentioned tribasic acid anhydride (or tribasic acid halide), saturated or unsaturated polybasic acids such as dicarboxylic acid and tetracarboxylic dianhydride are used, and the properties of the polyamideimide resin are impaired. It can be used in a range that does not exist.
Although it does not specifically limit as dicarboxylic acid, A terephthalic acid, isophthalic acid, adipic acid, sebacic acid, etc. are mentioned. The tetracarboxylic dianhydride is not particularly limited, and examples thereof include pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, and biphenyltetracarboxylic dianhydride. These may be used alone or in any combination of a plurality of types.
The total amount of carboxylic acids other than tribasic acids (dicarboxylic acid and tetracarboxylic acid) is preferably used in the range of 0 to 50 mol% in the total carboxylic acid from the viewpoint of maintaining the properties of the polyamideimide resin. More preferably, it is in the range of ˜30 mol%.

  Use ratio of diisocyanate (and diamine) and acid component (total amount of tribasic acid anhydride or tribasic acid anhydride halide and dicarboxylic acid and tetracarboxylic dianhydride used as required) is generated. From the viewpoint of the molecular weight of the polyamideimide resin and the degree of crosslinking, the diisocyanate compound (and diamine compound) is preferably 0.8 to 1.1 mol with respect to 1.0 mol of the total amount of the acid component, The amount is more preferably 1.08 mol, and particularly preferably 1.0 to 1.08 mol.

  In one embodiment, the polyamideimide resin may be a blocked polyamideimide resin in which a terminal isocyanate group is treated with a blocking agent (terminal blocking agent). Examples of endblocking agents that can be used include alcohols, oximes, and lactams. More specifically, examples of the alcohol include lower alcohols having 1 to 6 carbon atoms such as methanol, ethanol, and propanol. The oxime may be either aldoxime or ketoxime. For example, 2-butanone oxime can be preferably used. Examples of the lactam include δ-valerolactam and ε-caprolactam. The terminal blocking agent is not limited to the above exemplified compounds, and a plurality of types or a plurality of compounds may be used in combination. When a blocked polyamide resin is used in the water-based polyamideimide resin composition, decomposition due to hydrolysis is suppressed, and storage stability is easily improved.

  The number average molecular weight of the polyamideimide resin is preferably 5,000 or more, more preferably 10,000 or more, and further preferably 15,000 or more from the viewpoint of ensuring the strength of the coating film. On the other hand, from the viewpoint of ensuring solubility in water, the number average molecular weight is preferably 50,000 or less, more preferably 30,000 or less, and even more preferably 25,000 or less. In one embodiment, the number average molecular weight of the polyamideimide resin is preferably in the range of 15,000 to 25,000. When a polyamideimide resin having a number average molecular weight within the above range is used, it is easy to suppress a change in viscosity of the resin composition and obtain good storage stability.

  The number average molecular weight of the polyamideimide resin is sampled at the time of resin synthesis, measured by gel permeation chromatography (GPC) using a standard polystyrene calibration curve, and the synthesis is continued until the target number average molecular weight is reached. By doing so, it can be managed within the preferable range. The GPC measurement conditions will be described later.

  The polyamideimide resin preferably has an acid value of 10 to 80 mgKOH / g, which is a combination of the carboxyl group in the resin and the carboxyl group obtained by ring opening of the acid anhydride group. When the acid value is 10 mgKOH / g or more, the resin is easily dissolved or dispersed in the solvent, and the carboxyl group that reacts with the basic compound is sufficient, so that water-solubilization tends to be facilitated. . On the other hand, when the acid value is 80 mgKOH / g or less, the finally obtained polyamide-imide resin composition tends to become difficult to gel with time. From these viewpoints, the acid value is more preferably 25 mgKOH / g or more, more preferably 60 mgKOH / g or less, and even more preferably 50 mgKOH / g or less. In one embodiment, the acid value of the polyamideimide resin is preferably in the range of 35-50 mg KOH / g. When a polyamide-imide resin having an acid value within the above range is used, it is easy to suppress the viscosity change of the resin composition and increase the storage stability.

  The acid value can be obtained by the following method. First, about 0.5 g of polyamideimide resin composition was sampled, about 0.15 g of 1,4-diazabicyclo [2,2,2] octane was added thereto, and ion exchange with about 60 g of N-methyl-2-pyrrolidone was performed. Add about 1 mL of water and stir until the polyamideimide resin is completely dissolved. This was titrated with a potentiometric titrator using a 0.05 mol / L ethanolic potassium hydroxide solution, and the carboxyl groups in the polyamide-imide resin that had ring-opened carboxyl groups and acid anhydride groups were combined. Get the acid value.

  The amount of the polyamide-imide resin in the composition can be appropriately set according to its use, and is not particularly limited, but from the viewpoint of balance with other components, in a preferred embodiment, It is preferably 5% by mass or more, more preferably 10% by mass or more, further preferably 15% by mass or more, and on the other hand, preferably 50% by mass or less, and 40% by mass or less. More preferably, it is more preferably 30% by mass or less.

<N-ethyl-2-pyrrolidone>
The polyamideimide resin composition contains component (B) N-ethyl-2-pyrrolidone as an organic solvent.
The polyamideimide resin composition may contain an organic solvent other than N-ethyl-2-pyrrolidone as long as the effects of the present invention are not lowered.

  The other organic solvent is one or more selected from N-methyl-2-pyrrolidone, γ-butyrolactone, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidine, dimethylacetamide, dimethylformamide, N-acetylmorpholine, and the like. The polar solvent can be used. Furthermore, as cosolvents, ether compounds such as anisole, diethyl ether, ethylene glycol; ketone compounds such as acetophenone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexane, cyclopentanone; aromatic hydrocarbon solvents such as xylene, toluene; ethanol, An alcohol such as 2-propanol may optionally be used.

  The content of the organic mixed solvent containing N-ethyl-2-pyrrolidone or N-ethyl-2-pyrrolidone is 90 in the total amount of water (that is, in all the solvents) from the viewpoint of miscibility with water. It is preferable that it is mass% or less, and it is more preferable that it is 80 mass% or less. In the case of an organic mixed solvent, the content of N-ethyl-2-pyrrolidone in the organic mixed solvent is preferably 50% by mass or more in order to sufficiently exhibit the effects of the preferred embodiment, and 80 More preferably, it is at least mass%.

<Water>
The polyamideimide resin composition further contains water of component (C). As water, ion-exchanged water is preferably used.
The content of water is preferably 10% by mass or more, more preferably 15% by mass or more, and more preferably 25% by mass or more in the composition from the viewpoint of improving the solubility of the polyamideimide resin in water. On the other hand, water is preferably 80% by mass or less, more preferably 70% by mass or less, and further preferably 60% by mass or less in the composition. Further, the total amount of the organic solvent containing N-ethyl-2-pyrrolidone and water, that is, the total solvent in the composition is preferably 10% by mass or more (to 10% by mass or more of the solvent), More preferably, it is 20% by mass or more, more preferably 25% by mass or more, while the water to solvent ratio is preferably 90% by mass or less, more preferably 50% by mass or less. preferable.

<Basic compound>
In one embodiment, the polyamideimide resin composition can also be composed of the above components (A), (B) and (C). However, in order to improve the solubility of the polyamideimide resin in water, it is preferable to further contain a basic compound. Therefore, in a preferred embodiment, the polyamide resin composition contains a basic compound as component (D). The basic compound can increase the solubility of the resin in water by reacting with a carboxyl group contained in the polyamideimide resin to form a salt.
As basic compounds,
Triethylamine, tributylamine, N, N-dimethylcyclohexylamine, N, N-dimethylbenzylamine, triethylenediamine, N-methylmorpholine, N, N, N ′, N′-tetramethylethylenediamine, N, N, N ′, Alkylamines such as N ″, N ″ -pentamethyldiethylenetriamine, N, N ′, N′-trimethylaminoethylpiperazine, diethylamine, diisopropylamine, dibutylamine, ethylamine, isopropylamine, butylamine;
Monoethanolamine, diethanolamine, triethanolamine, dipropanolamine, tripropanolamine, N-ethylethanolamine, N, N-dimethylethanolamine, N, N-diethylethanolamine, cyclohexanolamine, N-methylcyclohexanolamine , Alkanolamines such as N-benzylethanolamine;
Is suitable.
In addition to the above basic compound, for example, a caustic alkali such as sodium hydroxide or potassium hydroxide, or aqueous ammonia may be used in combination.
In one embodiment, it is preferable to use alkanolamines as the basic compound, and it is more preferable to use N, N-dimethylethanolamine among them.

The basic compound has a viewpoint that the resin can be easily water-solubilized and the strength of the coating film is improved with respect to the acid value of the carboxyl group and the ring-opened acid anhydride group contained in the polyamideimide resin. Therefore, 2.5 to 10 equivalents are preferably used, more preferably 4 equivalents or more, and even more preferably 8 equivalents or less.
In one embodiment, the compounding amount of the basic compound is 4.5 to 6.5 equivalents based on the acid value of the carboxyl group and the ring-opened acid anhydride group contained in the polyamideimide resin. It is desirable to use it at a ratio of 5 to 6 equivalents.

  For the salt formation between the polyamideimide resin and the basic compound, the basic compound may be added to the polyamideimide resin composition containing water, or the basic compound may be added to the organic solvent solution of the polyamideimide resin not containing water. Water may be added after the addition. The temperature for forming the salt is preferably 0 ° C to 200 ° C, and more preferably in the range of 40 ° C to 130 ° C.

<Other ingredients>
In addition to the components (A) to (D), the polyamideimide resin composition of one embodiment can contain any component depending on the purpose of use. This composition can also contain polyamideimide resin other than the said polyamideimide resin in part.

  The polyamideimide resin composition can be preferably used as a paint. When the polyamideimide resin composition is used as a coating material, optional components such as pigments, fillers, antifoaming agents, preservatives, and surfactants may be added as necessary. Further, it may contain a resin other than the polyamide-imide resin, and details will be described in the section of paint.

2. Method for Producing Polyamideimide Resin A method for producing a polyamideimide resin includes a polymerization step in which a diisocyanate compound is reacted with a tribasic acid anhydride and / or a tribasic acid halide in an organic solvent. In a preferred embodiment, the organic solvent comprises N-ethyl-2-pyrrolidone. About the raw material compound to be used, it is as having demonstrated in the term of the said polyamide-imide resin composition.
In the case of producing a blocked polyamideimide resin, in addition to the polymerization step, a step of blocking the polyamideimide resin-terminated isocyanate group with a blocking agent such as alcohol is further included. As will be described later, the polymerization step and the blocking step may be performed in separate steps, but both steps may be performed simultaneously, that is, polymerization and blocking may be performed simultaneously.

  In the polymerization step, N-ethyl-2-pyrrolidone or an organic solvent containing N-ethyl-2-pyrrolidone can be used as a polymerization solvent (synthesis solvent). In that case, the obtained polymerization solution is used as it is as a polyamide. As an imide resin composition, it can be used for paints and the like. That is, N-ethyl-2-pyrrolidone is used for both the synthesis solvent and the coating solvent described later. The organic solvent other than N-ethyl-2-pyrrolidone is as described in the section of the polyamideimide resin composition.

Although there is no restriction | limiting in particular in the usage-amount of the solvent used at the time of superposition | polymerization, it is a viewpoint of the solubility of resin to set it as 50-500 mass parts with respect to 100 mass parts of total amounts of a diisocyanate component (and diamine component) and an acid component. To preferred.
The reaction temperature is not particularly limited, and is generally preferably a temperature of 80 to 180 ° C.
The polymerization reaction is preferably performed in an atmosphere such as nitrogen in order to reduce the influence of moisture in the air.

The polyamideimide resin can be produced, for example, by the following procedure.
(1) A method in which an acid component and a diisocyanate component (and a diamine component) are used at a time and reacted to synthesize a polyamideimide resin.
(2) After reacting an acid component with an excess of a diisocyanate component (and a diamine component) to synthesize an amide-imide oligomer having an isocyanate group or an amino group at the terminal, an acid component is added to the terminal isocyanate group. (And amino group) and a method of synthesizing a polyamideimide resin.
(3) After reacting an excess amount of the acid component with the diisocyanate component (and diamine component) to synthesize an amideimide oligomer having an acid or acid anhydride group at the terminal, a diisocyanate component and / or a diamine component are added. And reacting with the terminal acid or acid anhydride group to synthesize a polyamideimide resin.

When synthesizing a blocked polyamideimide resin, the blocking step may be performed by reacting a blocking agent (terminal blocking agent) during the synthesis of the resin, and simultaneously performing the polymerization step and the blocking step. You may make a blocking agent react with resin after a superposition | polymerization process. In the former case, a blocking agent may be added to the polymerization solvent.
The blending amount of the terminal blocking agent in blocking is preferably 1.0 to 10.0 parts by mass when the total amount of diisocyanate used in resin production is 100 parts by mass. From the viewpoint of storage stability, it is more preferably 2.5 to 5.0 parts by mass.

3. Method for Producing Polyamideimide Resin Composition Polyamideimide resin of a preferred embodiment comprising (A) a polyamideimide resin, (B) N-ethyl-2-pyrrolidone, (C) water, and (D) a basic compound. A composition can be preferably manufactured by adding water to the reaction solution containing the polyamideimide resin obtained by the manufacturing method of the said polyamideimide resin.
That is, in one embodiment, the method for producing a polyamideimide resin composition comprises:
A polymerization step of reacting a diisocyanate compound with a tribasic acid anhydride and / or a tribasic acid halide in an organic solvent containing N-ethyl-2-pyrrolidone, and adding the basic compound to the resulting resin solution A step of adding water later.
In another embodiment, the manufacturing method comprises:
A polymerization step of reacting a diisocyanate compound with a tribasic acid anhydride and / or a tribasic acid halide in an organic solvent, and after adding the basic compound to the obtained resin solution, water and an organic solvent for dilution Adding. In this embodiment, the organic solvent used in the polymerization step and / or the diluting organic solvent contains at least N-ethyl-2-pyrrolidone.
When a blocked polyamideimide resin is used as the polyamideimide resin, the blocking step may be performed simultaneously with the polymerization step, or a blocking step may be added separately.

4). Paint Polyamideimide resin composition can be diluted to an arbitrary concentration with water, and can form a coating film with excellent adhesion to the substrate even after high-temperature firing, so it should be used as a paint for various applications. Is preferred. That is, the coating material may contain a polyamide-imide resin composition, and optionally contain optional components such as pigments, fillers, antifoaming agents, preservatives, and surfactants. Further, it may further contain a resin other than the polyamide-imide resin.
When the polyamide-imide resin composition is used for coatings, it is preferably diluted arbitrarily with water or an organic solvent in order to obtain an appropriate viscosity according to the coating film forming method and the like.

In one embodiment, since the polyamideimide resin composition is excellent in the mixing property with the fluororesin aqueous dispersion, it is preferably used as a binder for the fluororesin. That is, in one embodiment, a fluorine paint containing a polyamideimide resin composition and a fluororesin can be configured. Hereinafter, an embodiment of a fluorine paint will be described as an example of the paint.
(Fluorine paint)
The fluorine paint includes a polyamideimide resin composition or a polyamideimide resin obtained by the above-described method for producing a polyamideimide resin, and a fluorine resin. Fluorine paints are suitable as paints for home appliances or kitchen appliances because they have excellent adhesion, heat resistance and hardness of the coating film.

  This fluorine paint for home appliances or kitchen appliances has a paint composition of a mixed system of a non-adhesive fluororesin and a polyamide-imide resin that exhibits adhesion to a base material. In order to orient the film surface, high-temperature baking is performed at around 400 ° C. at which fluorine melts.

  The above-mentioned polyamide-imide resin is preferably contained in the paint in an amount of 1 to 50% by mass in order to sufficiently exhibit its function. A plurality of types of polyamideimide resins may be used in combination, and a blocked polyamideimide resin may be included in part.

<Fluorine resin>
The fluororesin mixed with the fluorine paint is required to have characteristics such as non-adhesiveness, corrosion resistance, heat resistance and chemical resistance. Preferred examples of the fluororesin typically include a tetrafluoroethylene resin, a tetrafluoroethylene-perfluorovinyl ether copolymer, or a tetrafluoroethylene-hexafluoropropylene copolymer. You may use these individually or in combination of multiple types.
As the shape of the fluororesin, either an aqueous dispersion or a powder can be used, and the shape is not particularly limited. Although there is no restriction | limiting in particular in the mixing amount of a fluororesin, In order to obtain a coating film with good balance, such as high adhesiveness and non-adhesiveness, it shall be 50-800 mass parts with respect to 100 mass parts of polyamideimide resins. Is preferable, and it is more preferable to set it as 100-500 mass parts.

<Other ingredients>
In the above-mentioned fluorine paint or other paint, polyethersulfone resin (PES), polyimide resin (PI), polyamide resin, epoxy compound, isocyanate compound, melamine compound, etc. may be used alone or mixed as necessary. Can be used.

  In a preferred embodiment, the paint may include an epoxy compound (epoxy resin). By blending the epoxy compound, the thermal, mechanical and electrical properties of the polyamide-imide resin can be further improved. Moreover, since an epoxy compound (epoxy resin), a melamine compound (melamine resin), and an isocyanate compound can improve the adhesiveness of a coating film more, it is preferable.

Examples of the epoxy compound include bisphenol type epoxy resins (bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, brominated bisphenol A type epoxy resin, bisphenol S type epoxy resin, etc.), biphenyl type, and the like. Epoxy resin, phenol novolac type epoxy resin, brominated phenol novolac type epoxy resin, o-cresol novolac type epoxy resin, flexible epoxy resin, polyfunctional epoxy resin, amine type epoxy resin, heterocyclic ring containing epoxy resin, alicyclic type Examples thereof include an epoxy resin, triglycidyl isocyanurate, and a bixylenol type epoxy resin. These epoxy compounds may be used alone or in combination of two or more.
In addition, although an epoxy compound may be added independently and may be made to react with a polyamide-imide resin, you may add with a hardening | curing agent or a hardening accelerator so that the unreacted substance of an epoxy compound may not remain after hardening.

  Examples of the isocyanate compound include polyisocyanates of hexamethylene diisocyanate such as duranate, and polyisocyanates synthesized from 4,4'-diphenylmethane diisocyanate. The mass average molecular weight of the polyisocyanate is preferably 500 to 9000, more preferably 1000 to 5000.

  Although there is no restriction | limiting in particular as a melamine compound, For example, the methylol group containing compound which made formaldehyde, paraformaldehyde, etc. react with melamine is mentioned. This methylol group is preferably etherified with an alcohol having 1 to 6 carbon atoms.

  Each compounding amount of the epoxy compound, the isocyanate compound, and the melamine compound contained in the paint is preferably 1 part by mass or more, for example, in order to exert an adhesion improvement effect with respect to 100 parts by mass of the polyamideimide resin. From the viewpoint of maintaining the heat resistance and strength of the polyamideimide resin composition, it is preferably 40 parts by mass or less, and more preferably 30 parts by mass or less. .

  The paint preferably contains a surfactant as necessary. The surfactant is not particularly limited, but does not cause phase separation or phase separation until the coating composition is uniformly mixed and the coating is dried, and many residues after baking the coating. The thing which does not remain is preferable.

  Although the content of the surfactant is not particularly limited, in order to maintain a uniform mixed state of the coating composition and not to leave a large amount after baking so as not to adversely affect the film formability. Furthermore, it is preferable that it is 0.01-10 mass% in a coating material, and it is more preferable that it is 0.5-5 mass%.

  The paint may contain a filler in order to improve the water resistance of the coating film. The type of filler can be selected according to the application of the coating film in consideration of its water resistance, chemical resistance, etc., and is preferably one that does not dissolve in water. Specifically, the filler includes metal powder, metal oxide (aluminum oxide, zinc oxide, tin oxide, titanium oxide, etc.), glass beads, glass flakes, glass particles, ceramics, silicon carbide, silicon oxide, fluoride. Calcium, carbon black, graphite, mica, barium sulfate and the like can be mentioned. These may be used alone or in combination of two or more.

As another embodiment of the coating material, a conductive coating material (conductive composition) including a polyamideimide resin composition and a conductive material can be configured. Since the polyamideimide resin composition can exhibit excellent adhesion to the base material and the conductive material, the conductive composition can be suitably used for applications such as circuit formation or electrode formation. In addition, you may make a conductive coating material into the shape of a paste by adjusting the quantity of a solvent suitably.
The conductive material may be, for example, a conductive inorganic material or a carbon material. Although it does not specifically limit, When using for electrode formation, it is preferable that an electroconductive coating material contains a polyamidoimide resin composition, a positive electrode active material, or a negative electrode active material, and also contains a conductive support agent. The active material and the conductive additive are preferably appropriately selected depending on the form of various batteries. For example, when forming the negative electrode of a lithium battery, a carbon material or a silicon material can be used. Since the electrode of the lithium battery is also required to have solvent resistance, the conductive paint may further contain the fluororesin described in the above-mentioned fluoro paint. Moreover, you may contain other components, such as a dispersing agent, as needed.

  As mentioned above, although the coating material was demonstrated along the typical use, the coating method of a coating material is not specifically limited, A well-known coating method is applicable. Typical coating methods include, for example, dipping coating, spray coating, and brush coating. It is preferable to dilute to an appropriate concentration by appropriately adjusting the amount of solvent according to the coating method.

  After applying the paint, it is dried (preliminary drying) and cured (baked) to form a coating film. The conditions for drying and curing are not particularly limited, and are preferably set as appropriate according to the heat resistance characteristics of the substrate to be used. In order to ensure the adhesion and toughness of the coating film, it is preferable to perform heating at 250 ° C. or higher. In the case of a fluorine paint, in order to orient the fluororesin on the surface of the coating film at the time of firing the coating film, it is preferable to perform high-temperature baking in the vicinity of 400 ° C. at which the fluororesin melts, and the temperature is 330 ° C. to 420 ° C., time Is preferably performed in about 10 to 30 minutes. By baking, the fluororesin moves to the surface of the coating film and melts to form a film.

5). Base material or article The base material or article of the present embodiment has a coating film formed by the coating material on at least a part of the surface of the base material or the article. Therefore, for example, a base material or an article has a coating film formed from the above-mentioned fluorine paint or conductive paint.
In one embodiment, the coating film can be formed on the surface of various substrates or articles that require safety and boiling resistance, etc. for the coating film. For this embodiment, a fluorine paint is preferably used. can do. The surface on which the coating film is formed is preferably a surface exposed to water vapor and / or a surface exposed to high temperature.

In the said embodiment, a cooking household appliance or a kitchen appliance etc. are mentioned as a specific example of articles | goods. Examples of kitchen utensils include utensils that may come into contact with boiling water or steam, such as pans, pressure cookers, and frying pans. More specifically, pans and pressure cookers in which the above coating film is formed on the inner surface. Or frying pans and their lids. In addition, examples of cooking appliances (kitchen appliances) include rice cookers, hot plates, electric kettles, microwave ovens, microwave ovens, and gas ranges, and more specifically, rice cookers with the above-mentioned coating film formed on the inner surface. Examples include an inner pot and a lid of a vessel, a microwave oven in which the above-mentioned coating film is formed on the inner surface, a gas range top plate on which the above-mentioned coating film is formed on the surface.
It is preferable that a base material is what is used for these cooking household appliances or kitchen appliances.

The polyamide-imide resin composition and paints (including fluorine paints and conductive paints) containing the polyamide-imide resin as a coating film component have low toxicity, so that the work environment can be improved. A water-based resin composition Therefore, it can reduce the burden on the environment and contribute to VOC reduction. Moreover, since it is excellent in storage stability, the characteristic fall after a preservation | save is suppressed and it is easy to obtain the desired preferable characteristic.
In particular, in the embodiment of the fluorine paint, it is possible to form a coating film having excellent adhesion to a substrate and steam resistance even after baking at a higher temperature than before by applying and curing to a coating object. . Therefore, it has a great benefit for various uses such as home appliances or kitchen appliances in which safety, boiling resistance or steam resistance, and heat resistance are required for the coating film on the surface.

  Next, although various examples are described, it is needless to say that preferred embodiments are not limited to these examples, and include many other embodiments based on the gist of the invention.

The number average molecular weight and acid value of the polyamideimide resin were measured as follows.
<Number average molecular weight>
GPC model: HLC-8320GPC manufactured by Tosoh Corporation
Detector: RI manufactured by Tosoh Corporation
Wavelength: 270nm
Data processor: ATT 8
Column: Gelpack GL-S300MDT-5 × 2
Column size: 8mmφ × 300mm
Column temperature: 40 ° C
Solvent: DMF / THF = 1/1 (liter) + phosphoric acid 0.06M + lithium bromide 0.06M Sample concentration: 5 mg / 1 mL
Injection volume: 5 μL
Pressure: 49 kgf / cm ² (4.8 × 10 ⁶ Pa)
Flow rate: 1.0 mL / min
<Acid value>
0.5 g of the polyamideimide resin composition was sampled, 0.15 g of 1,4-diazabicyclo [2,2,2] octane was added thereto, and about 60 g of N-methyl-2-pyrrolidone and about 1 mL of ion-exchanged water were added. In addition, the mixture was stirred until the polyamideimide resin was completely dissolved. This was titrated with a potentiometric titrator using a 0.05 mol / L ethanolic potassium hydroxide solution, and the carboxyl groups in the polyamide-imide resin that had ring-opened carboxyl groups and acid anhydride groups were combined. The acid value was obtained.

<Example 1>
304.1 g of trimellitic anhydride, 396.2 g of 4,4′-diphenylmethane diisocyanate, and 700.3 g of N-ethyl-2-pyrrolidone were placed in a flask equipped with a thermometer, a stirrer, and a condenser tube and dried. The temperature was gradually raised to 90 ° C. over 1 hour with stirring in a nitrogen stream. After heating for 2 hours, the temperature was gradually raised to 120 ° C. while paying attention to the sudden bubbling of carbon dioxide gas generated by the reaction. After heating was started for 5 hours, the reaction was stopped, An imide resin solution was obtained.
The nonvolatile content (200 ° C./2 hours) of this polyamideimide resin solution was 48% by mass. The number average molecular weight of the polyamideimide resin was 15,000, and the acid value of the carboxyl group obtained by ring-opening the carboxyl group and the acid anhydride group was 45 mgKOH / g.

  1200 g of the obtained polyamideimide resin solution was put into a flask equipped with a thermometer, a stirrer, and a cooling tube, and gradually heated to 70 ° C. while stirring in a dried nitrogen stream. When the temperature reached 70 ° C., 205.9 g (5 equivalents) of N, N-dimethylethanolamine was added, and after sufficiently stirring while maintaining at 70 ° C., ion-exchanged water was gradually added while stirring. Finally, ion-exchanged water was added until the amount reached 624.0 g (50% by mass with respect to the solvent) to obtain a transparent and uniform polyamideimide resin composition (aqueous heat-resistant resin composition).

<Example 2>
467.0 g of trimellitic anhydride, 608.4 g of 4,4′-diphenylmethane diisocyanate, and 1165.0 g of N-ethyl-2-pyrrolidone were placed in a flask equipped with a thermometer, a stirrer, and a condenser tube and dried. While stirring in a nitrogen stream, the temperature was gradually raised to 100 ° C. over 1 hour. After heating for 2 hours, the temperature was gradually raised to 140 ° C. while paying attention to the sudden foaming of carbon dioxide gas generated by the reaction. After heating for 4 hours from the start of heating, the reaction was stopped, An imide resin solution was obtained.

  The nonvolatile content (200 ° C./2 hours) of this polyamideimide resin solution was 45% by mass. The number average molecular weight of the polyamideimide resin was 20,000, and the acid value of the carboxyl group obtained by ring-opening the carboxyl group and the acid anhydride group was 35 mgKOH / g.

  1850 g of the obtained polyamideimide resin solution was put into a flask equipped with a thermometer, a stirrer, and a cooling tube, and gradually heated while stirring in a dried nitrogen stream, and the temperature was raised to 80 ° C. When the temperature reached 80 ° C., 76.9 g (6 equivalents) of N, N-dimethylethanolamine was added, and the mixture was sufficiently stirred while being kept at 80 ° C. Then, ion-exchanged water was gradually added while stirring. Finally, ion-exchanged water was added until 832.7 g (45% by mass with respect to the solvent) to obtain a transparent and uniform polyamideimide resin composition (water-based heat-resistant resin composition).

<Example 3>
162.3 g of trimellitic anhydride, 152.3 g of 4,4′-diphenylmethane diisocyanate, 62.5 g of 3,3′-dimethoxybiphenyl-4,4′-diisocyanate, and 460.9 g of N-ethyl-2-pyrrolidone, It put into the flask provided with the thermometer, the stirrer, and the cooling pipe, and heated up gradually to 100 degreeC over 2 hours, stirring in the dried nitrogen stream. The temperature was kept at 100 ° C. while paying attention to the sudden foaming of carbon dioxide gas generated by the reaction, and the heating was continued for 7 hours, and then the reaction was stopped to obtain a polyamideimide resin solution.

  The nonvolatile content (200 ° C./2 hours) of this polyamideimide resin solution was 42% by mass. The number average molecular weight of the polyamideimide resin was 15,000, and the acid value of the carboxyl group obtained by ring-opening the carboxyl group and the acid anhydride group was 45 mgKOH / g.

  600 g of the obtained polyamideimide resin solution was put into a flask equipped with a thermometer, a stirrer, and a cooling tube, and gradually heated to 60 ° C. while stirring in a dried nitrogen stream. When the temperature reached 60 ° C., 90.1 g (5 equivalents) of N, N-dimethylethanolamine was added and sufficiently stirred while maintaining the temperature at 60 ° C., and then ion-exchanged water was gradually added while stirring. Finally, ion-exchanged water was added until the amount reached 232.0 g (based on a solvent ratio of 40% by mass) to obtain a transparent and uniform polyamideimide resin composition (aqueous heat-resistant resin composition).

<Comparative Example 1>
196.7 g of trimellitic anhydride, 256.3 g of 4,4′-diphenylmethane diisocyanate, and 553.7 g of N-ethyl-2-pyrrolidone were placed in a flask equipped with a thermometer, a stirrer, and a condenser tube and dried. While stirring in a nitrogen stream, the temperature was gradually raised to 100 ° C. over 1 hour. After heating for 1 hour, the temperature was gradually raised to 130 ° C. while paying attention to the sudden foaming of carbon dioxide gas generated by the reaction. After heating for 6 hours from the start of heating, the reaction was stopped, and polyamide An imide resin solution was obtained.

  The nonvolatile content (200 ° C./2 hours) of this polyamideimide resin solution was 42% by mass. The number average molecular weight of the polyamideimide resin was 30,000, and the acid value of the carboxyl group obtained by ring-opening the carboxyl group and the acid anhydride group was 25 mgKOH / g.

  650 g of this polyamideimide resin solution was placed in a flask equipped with a thermometer, a stirrer, and a cooling tube, and gradually heated to 70 ° C. while stirring in a dried nitrogen stream. When the temperature reached 70 ° C., 86.8 g (8 equivalents) of N, N-dimethylethanolamine was added, and after sufficiently stirring while maintaining at 70 ° C., ion-exchanged water was gradually added while stirring. Finally, ion-exchanged water was added until the amount reached 251.3 g (ratio to solvent: 40% by mass) to obtain a transparent and uniform polyamideimide resin composition (aqueous heat-resistant resin composition).

<Viscosity change rate (%)>
For the polyamideimide resin compositions (varnishes) obtained in the above Examples and Comparative Examples, the rate of change in viscosity (%) before and after storage for 7 days at 60 ° C. was calculated according to the following procedure.
First, the viscosity of the polyamideimide resin composition (varnish) was measured before storage. Next, a certain amount of the resin composition (varnish) was put in a sealed container, and the sealed container was stored in a dryer set at 60 ° C. for 7 days, and then the viscosity was measured. From each measured value, the viscosity change rate was calculated according to the following (formula 1).
(Formula 1)
Viscosity change rate (%) = (V2−V1) / V1 × 100
In Formula 1, “V1” represents the viscosity measured before storage. “V2” represents the viscosity measured after storage at 60 ° C. for 7 days.
Each viscosity was measured according to JIS C 2103 and using a B-type rotational viscometer under the conditions of 25 ° C., rotor No. 3, and a rotational speed of 12 rpm.

<Evaluation>
(Appearance of varnish)
The polyamideimide resin compositions (varnishes) obtained in the above Examples and Comparative Examples were each put in a sealed container and stored in an environment of 60 ° C., and the appearance of the varnish after 7 days was observed visually.
(Adhesion reduction rate)
The polyamide-imide resin composition (test paint) obtained in the above Examples and Comparative Examples was applied on an aluminum substrate (1 × 50 × 150 mm, manufactured by Partec Co., Ltd.). Next, an adhesion test was performed according to the following procedure.
That is, after the said board | substrate which apply | coated each test coating material was pre-dried at 80 degreeC for 10 minute (s), it baked at 400 degreeC for 10 minute (s), and the coating film thickness obtained 10 micrometers by the average value of five places. . Cuts were made into this coating film to produce 10 × 10 squares of 1 mm square, peeled five times using an adhesive tape (manufactured by Nichiban Co., Ltd.), and the number of remaining squares was counted.
The above adhesion test was carried out for both the resin composition before heat storage and the resin composition after storage for 7 days at 60 ° C., and the adhesion reduction rate (%) was determined according to the following (formula 2). Calculated.
(Formula 2)
Adhesion reduction rate (%) = (A2-A1) / A1 × 100
In Formula 2, “A1” represents an evaluation result of adhesion performed using the resin composition before storage. “A2” represents an evaluation result of adhesion performed using the resin composition after storage at 60 ° C. for 7 days.

Each evaluation result is shown in Table 1.

As shown in Table 1, all the polyamideimide resin compositions obtained in each Example had a viscosity change rate of -30% or less, and there was no decrease in adhesion after storage at 60 ° C for 7 days. The characteristics are maintained. On the other hand, the resin composition obtained in Comparative Example 1 had a viscosity change rate exceeding −30%, and the adhesion after storage at 60 ° C. for 7 days was significantly reduced. In addition, the external appearance of each polyamideimide resin composition of each Example and Comparative Example 1 after being stored at 60 ° C. for 7 days was transparent. This is presumed to be related to the decrease in the viscosity of the resin composition after storage. Actually, there is a clear difference in the rate of decrease in adhesion after storage between the example and the comparative example, so that according to the example, it is possible to improve the storage stability in terms of characteristics. Recognize.
In view of the above, in a resin composition using a solvent other than NMP, excellent storage stability can be obtained by reducing the viscosity reduction before and after storage for 7 days at 60 ° C. It turns out that it can suppress.

Claims (8)

  (A) Polyamideimide resin, (B) N-ethyl-2-pyrrolidone, (C) water, and (D) Basic compound, viscosity change rate before and after storage at 60 ° C. for 7 days is −30% Polyamideimide resin composition that is within.   The polyamideimide resin composition according to claim 1, wherein the (A) polyamideimide resin has a number average molecular weight of 5,000 to 50,000.   The polyamideimide resin composition according to claim 1 or 2, wherein an acid value of the carboxyl group of the (A) polyamideimide resin and a carboxyl group obtained by ring-opening an acid anhydride group is 10 to 80 mgKOH / g. .   The polyamideimide resin composition according to any one of claims 1 to 3, wherein a content of the (C) water is 10% by mass or more based on a total mass of the resin composition.   A fluorine paint comprising the polyamideimide resin composition according to any one of claims 1 to 4 and a fluorine resin.   The base material which has the coating film formed with the fluorine coating material of Claim 5 on at least one part surface.   An article having a coating film formed of the fluorine paint according to claim 5 on at least a part of its surface.   The electroconductive composition containing the polyamideimide resin composition of any one of Claims 1-4, and an electroconductive material.