JP2019026771A - Polyamideimide resin composition for nonwoven fabric production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyamide-imide resin composition which can dissolve a polyamide-imide resin in the same manner as NMP, contains an organic solvent having excellent drying property, and can be suitably used for producing a non-woven fabric having excellent heat resistance. .. A polyamide-imide resin composition for producing a nonwoven fabric, which comprises (A) a polyamide-imide resin having a number average molecular weight of 20,000 or more and (B) dimethylacetamide. [Selection diagram] None

Description

  Embodiments of the present disclosure relate to a polyamideimide resin composition, and more particularly, to a polyamide resin composition that can be suitably used for manufacturing a nonwoven fabric.

  Nonwoven fabrics can be used in various fields. For example, they are used as battery separators and various filters. A nonwoven fabric is manufactured through the spinning process using the material selected according to the use and the intended purpose, for example. For example, in applications of battery separators, excellent heat resistance is required. In addition, excellent heat resistance is also required for applications of filters used in high temperature environments, and further improvement in heat resistance is desired due to diversification of these usage forms. On the other hand, a polyamide-imide resin having excellent heat resistance and excellent chemical resistance and solvent resistance has attracted attention as a fiber material or a nonwoven fabric material (Patent Document 1).

Japanese Patent No. 4797863

  N-methyl-2-pyrrolidone (NMP) is widely used as a good solvent for polyamideimide resin, but in recent years, regulations on the use of NMP have become stricter from the viewpoint of environmental protection and safety and health. Moreover, since NMP has a high boiling point of 200 ° C. or higher, the drying property is poor, and stickiness of the fibers after spinning is likely to occur. Therefore, there is a demand for a polyamide-imide resin composition suitable for the production of nonwoven fabrics using an organic solvent that can dissolve polyamide-imide resin in the same manner as NMP but can obtain good drying properties at a relatively low temperature. .

  Examples of organic solvents that can dissolve the polyamideimide resin and have a relatively low boiling point include dimethylacetamide (DMAC) and dimethylformamide (DMF). However, the polyamideimide resin obtained by synthesizing using an organic solvent such as DMAC or DMF has lower properties such as mechanical strength and heat resistance than the polyamideimide resin obtained by synthesizing using NMP. Tend to be. On the other hand, generally, when the heat resistance of the polyamideimide resin is increased, the solubility of the resin tends to decrease, and it is difficult to adjust the balance between the heat resistance and the solubility. Therefore, when manufacturing a fiber and a nonwoven fabric using a polyamidoimide resin solution, if the heat resistance of polyamidoimide resin is raised, since the solubility of resin will fall easily, it will be easy to produce a malfunction at the time of spinning. For these reasons, further development of a polyamideimide resin composition is desired for the realization of a nonwoven fabric excellent in heat resistance.

  Therefore, the embodiment of the present invention can dissolve a polyamideimide resin equivalent to NMP, includes an organic solvent having excellent drying properties, and can be suitably used for the production of a nonwoven fabric having excellent heat resistance. It is an object to provide a composition.

  A non-woven fabric is a fiber obtained by spinning and entangled into a sheet shape without weaving, and the molding is performed by applying heat or applying mechanical or chemical treatment. In various studies, the present inventors prefer a resin having a glass transition temperature (Tg) of 270 ° C. or higher as a resin used for the fiber material in order to constitute a heat-resistant nonwoven fabric. I found out. And by comprising the resin composition containing a polyamidoimide resin having a number average molecular weight of 20,000 or more and dimethylacetamide, a good balance between heat resistance and solubility can be obtained. It has been found that it can be suitably used, and the present invention has been completed.

That is, the embodiment of the present invention relates to a polyamide-imide resin composition for producing a nonwoven fabric, comprising (A) a polyamide-imide resin having a number average molecular weight of 20,000 or more and (B) dimethylacetamide.
Other embodiment is related with the nonwoven fabric formed using the said polyamide-imide resin composition.

  According to this embodiment, the polyamide-imide resin composition which can be used conveniently for manufacture of the nonwoven fabric by which the outstanding heat resistance is requested | required can be provided. Since the said polyamideimide resin composition contains dimethylacetamide as a solvent, it is preferable also from a viewpoint of environmental conservation and safety and health.

Hereinafter, preferred embodiments will be described. However, the present invention is not limited to the following embodiments.
1. Polyamideimide resin composition When using non-woven fabric for heat-resistant filters used in high-temperature environments such as battery separators and fuel exhaust gas filters, the resin has a glass transition temperature of 270 ° C or higher from the viewpoint of obtaining sufficient heat resistance. It is preferable to have (Tg). In addition, Tg described in this specification means a value obtained by measurement according to a TMA (Thermal Mechanical Analysis) method, and details will be described later in Examples. The Tg of the resin is more preferably 275 ° C. or higher, and further preferably 280 ° C. or higher.
On the other hand, in one embodiment, the polyamide-imide resin composition includes (A) a polyamide-imide resin having a number average molecular weight of 20,000 or more and (B) dimethylacetamide as a solvent. According to the polyamideimide resin composition of the above embodiment, it is easy to obtain a Tg of 270 ° C. or more by using a polyamideimide resin having a number average molecular weight of 20,000 or more, and excellent in dimethylacetamide. High solubility can also be obtained. Therefore, a nonwoven fabric excellent in heat resistance can be efficiently produced using the polyamideimide resin composition. The nonwoven fabric can be suitably used for applications requiring high heat resistance such as battery separators and heat-resistant filters. Hereinafter, the components of the polyamideimide resin composition will be described. In the following description, the polyamideimide resin composition may be referred to as “resin composition”.

<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 the polyamide produced From the viewpoint of the molecular weight of the imide resin and the degree of crosslinking, the diisocyanate compound (and diamine compound) is preferably 0.8 to 1.1 mol with respect to the total amount of 1.0 mol of the acid component, 0.95 to 1. The amount is more preferably 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. In the polyamideimide resin composition, when a blocked polyamide resin is used, decomposition due to hydrolysis is suppressed and stability over time is improved, so that excellent heat resistance can be easily obtained.

In one embodiment, the number average molecular weight of the polyamideimide resin is preferably 5,000 or more, more preferably 10,000 or more, and more preferably 15,000 or more from the viewpoint of ensuring mechanical strength in the spinning process. More preferably. Moreover, it is preferable that it is 20,000 or more from a viewpoint of ensuring the desired heat resistance when shape | molded in the form of a nonwoven fabric. On the other hand, the number average molecular weight is preferably 50,000 or less and more preferably 45,000 or less from the viewpoint of ensuring solubility in a solvent and easily obtaining a viscosity suitable for the spinning process. Preferably, 40,000 or less is more preferable.
In one embodiment, the number average molecular weight of the polyamideimide resin is preferably in the range of 20,000 to 35,000. When a polyamideimide resin having a number average molecular weight within the above range is used, it becomes easy to obtain a good balance between heat resistance and solubility, and the spinning process can be carried out satisfactorily.

  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 above-mentioned polyamideimide resin is preferably contained in the resin composition 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.

  The amount of the polyamideimide resin in the resin composition can be appropriately set and is not particularly limited. In a preferred embodiment, from the viewpoint of balance with other components, the amount of the polyamideimide resin in the resin composition is preferably 5% by mass or more, more preferably 10% by mass or more, More preferably, it is at least mass%. On the other hand, it is preferably 50% by mass or less, more preferably 40% by mass or less, and further preferably 30% by mass or less. By adjusting the amount of the polyamideimide resin in the resin composition within the above range, it becomes easy to obtain fibers having sufficient strength at the time of spinning, and also maintains good workability by suppressing the decrease in fluidity. can do.

<Dimethylacetamide>
The polyamide-imide resin composition contains component (B) dimethylacetamide as a solvent. The polyamideimide resin composition may contain a solvent other than dimethylacetamide as long as the effects of the present invention are not lowered.

  Other solvents include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidine, dimethylacetamide, dimethylformamide, and N-acetyl. One or more polar solvents selected from morpholine and the like, or water 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.

  When a solvent other than dimethylacetamide is used as the solvent, the content of dimethylacetamide in the mixed solvent is preferably 50% by mass or more in order to sufficiently exhibit the effects of the preferred embodiment. 80% by mass or more is more preferable.

<Other ingredients>
The polyamide-imide resin composition can contain any component depending on the purpose of use in addition to the (A) polyamide-imide resin and (B) dimethylacetamide.

  In one embodiment, in the case of constituting an aqueous resin composition, the resin composition preferably contains a basic compound in order to enhance the solubility of the polyamideimide resin in water. 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 the basic compound, alkylamines or alkanolamines can be preferably used. In addition to the basic compound, for example, a caustic alkali such as sodium hydroxide or potassium hydroxide, or aqueous ammonia may be used in combination.

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.
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.

  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.

The polyamide-imide resin composition can be used for various applications such as a coating agent for various equipment and a molded article material. In one embodiment, the polyamideimide resin composition can be suitably used as a fiber material, and can be more preferably used as a nonwoven material.
Depending on these uses and usage forms, the polyamideimide resin composition may further contain optional components such as pigments, fillers, antifoaming agents, preservatives, surfactants, thickeners, etc., as necessary. . In one embodiment, the resin composition may contain a resin other than a polyamideimide resin. For example, a fluororesin, a polyethersulfone resin (PES), a polyimide resin (PI), a polyamide resin, an epoxy compound, an isocyanate compound, a melamine compound, or the like can be used alone or in combination as necessary.
For example, as the fluororesin, a tetrafluoroethylene resin, a tetrafluoroethylene-perfluorovinyl ether copolymer, or a tetrafluoroethylene-hexafluoropropylene copolymer can be preferably used. You may use combining these multiple types. When a fluororesin is added to the resin composition, it becomes easy to impart characteristics such as non-adhesiveness, corrosion resistance, heat resistance, and chemical resistance.

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.
The epoxy compound may be added alone and allowed to react with the polyamideimide resin, but may be added together with a curing agent or a curing accelerator so that an unreacted product of the epoxy compound does not remain after molding.

  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.

  In a preferred embodiment, the resin composition further comprises an epoxy compound (epoxy resin). By blending the epoxy compound, the thermal, mechanical, and electrical characteristics of the polyamide-imide resin composition can be further improved.

  Each compounding amount of the epoxy compound, isocyanate compound, and melamine compound contained in the resin composition is preferably, for example, 1 part by mass or more, and 5 parts by mass or more, with respect to 100 parts by mass of the polyamideimide resin. It is more preferable. On the other hand, from the viewpoint of maintaining the heat resistance and strength of the polyamideimide resin composition, the amount is preferably 40 parts by mass or less, and more preferably 30 parts by mass or less.

  In one Embodiment, when manufacturing a nonwoven fabric using a resin composition, it is preferable that the resin composition contains surfactant as needed. The surfactant is not particularly limited, but a non-woven fabric in which the resin composition is uniformly mixed and does not cause phase separation or phase separation until the fibers are dried after spinning and the fibers are aggregated. Those which do not leave much residue when constructed are preferred.

  The content of the surfactant is not particularly limited, but in order to maintain a uniform mixed state of the resin composition and not adversely affect the production of the nonwoven fabric, It is preferable that it is 0.01-10 mass%, and it is more preferable that it is 0.5-5 mass%.

  The resin composition may contain a filler in order to improve the water resistance of the nonwoven fabric. The type of filler can be selected according to the use of the nonwoven fabric 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.

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 dimethylacetamide. 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, dimethylacetamide or a solvent containing dimethylacetamide can be used as a polymerization solvent (synthetic solvent). In that case, the obtained polymerization solution is used as a polyamideimide resin composition as it is for a nonwoven fabric material or the like. be able to. That is, dimethylacetamide is used as both a synthesis solvent and a dilution solvent described later. The solvent other than dimethylacetamide 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 the 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 a terminal acid or acid anhydride group to synthesize a polyamideimide resin.

When synthesizing the blocked polyamideimide resin, the blocking step may be performed by reacting the blocking agent during the synthesis of the resin, and the polymerization step and the blocking step may be performed simultaneously, or the resin after the polymerization step. You may make a blocking agent react. 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 The polyamideimide resin composition containing (A) the above-mentioned polyamideimide resin having a number average molecular weight of 20,000 or more and (B) dimethylacetamide is a method for producing the polyamideimide resin. The reaction solution containing the polyamideimide resin obtained by the above can be used as it is. If necessary, a diluting solvent may be added.
That is, in one embodiment, the method for producing a polyamideimide resin composition comprises:
It includes a polymerization step in which a diisocyanate compound is reacted with a tribasic acid anhydride and / or a tribasic acid halide in a solvent containing dimethylacetamide.
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 a solvent containing the diisocyanate compound, and a step of adding a dilution solvent to the obtained resin solution or resin. In this embodiment, the solvent and / or dilution solvent used during the polymerization step includes at least dimethylacetamide.
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. Moreover, when comprising a water-based resin composition, the water-solubilization process using a basic compound can be performed after the said polymerization process, and water can also be used as a dilution solvent.

4). Nonwoven fabric and method for producing the same The polyamideimide resin composition is excellent in heat resistance and has good solubility of the resin in the resin composition, and therefore various spinning methods for producing fibers can be applied. Especially, although it does not specifically limit, since the drying property of a solvent is favorable, a polyamide-imide resin composition becomes a material suitable for a dry spinning method. When the polyamideimide resin composition is spun, it is preferably diluted with a solvent in order to obtain an appropriate viscosity according to each spinning method. However, from the viewpoint of obtaining excellent drying properties, the resin composition is preferably non-aqueous.

  In the dry spinning method, the polyamideimide resin composition (solution) is discharged through a spinning nozzle, and the solvent can be dried to obtain fibers. In one embodiment, a nonwoven fabric can be obtained by forming an aggregate of fibers obtained by spinning into a predetermined shape under heating and partially welding (bonding) the fibers together. The welding of the fibers is not limited to heating, and can be carried out, for example, by spraying a solution containing a binder resin for bonding onto an aggregate of fibers made of polyamideimide resin. As the binder resin for bonding, polyether sulfone resin (PES), polyimide resin (PI), polyamide resin, epoxy compound, isocyanate compound, melamine compound, and the like can be used alone or in combination. Details of these resins are as described in the section of the polyamideimide resin composition.

In one Embodiment, a nonwoven fabric can be suitably manufactured according to the electrospinning method (charge spinning method). The electrospinning method is a method in which a positive high voltage is applied to a resin solution, and the resin solution is sprayed on a grounded or negatively charged surface to cause fiberization. A fiber having excellent uniformity can be obtained. In addition, since the fiber can be formed on the target plate in a two-dimensionally spread state, a nonwoven fabric can be obtained without forming the fiber again after spinning. Thus, since the nonwoven fabric manufactured by the electrospinning method is comprised from a fine fiber, it becomes easy to obtain the high performance nonwoven fabric excellent in the separability.
Therefore, in one embodiment, by using the polyamideimide resin composition (solution) of the above embodiment and producing a nonwoven fabric according to the electrospinning method, it is excellent in heat resistance and separability in a simple process. An excellent and high quality nonwoven fabric can be obtained. Such a nonwoven fabric can be used for various uses, for example, can be suitably used as a separator for electrodes and a heat resistant filter that require excellent heat resistance.

  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 of the polyamideimide resin was 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

<Example 1>
Trimellitic anhydride (313.6 g), 4,4′-diphenylmethane diisocyanate (408.5 g), and dimethylacetamide (882.6 g) were placed in a flask equipped with a thermometer, a stirrer, and a condenser, and stirred in a dry nitrogen stream. The temperature was gradually raised to 90 ° C. over 1 hour. After heating for 3 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 (resin composition) was obtained. When this polyamideimide resin solution was allowed to stand to room temperature and the appearance was visually observed, it was uniform and transparent.
The nonvolatile content (200 ° C./2 hours) of this polyamideimide resin solution was 40% by mass, and the number average molecular weight of the polyamideimide resin was 25,000.

<Example 2>
482.6 g of trimellitic anhydride, 631.2 g of 4,4′-diphenylmethane diisocyanate, and 1670.7 g of dimethylacetamide were placed in a flask equipped with a thermometer, a stirrer, and a condenser, and stirred in a dried nitrogen stream. The temperature was gradually raised to 80 ° C. over 1 hour. After heating for 4 hours, the temperature was gradually raised to 150 ° C. while paying attention to the sudden foaming of carbon dioxide gas generated by the reaction, and after 5 hours from the start of heating, the reaction was stopped and the polyamide was stopped. An imide resin solution (resin composition) was obtained. When this polyamideimide resin solution was allowed to stand to room temperature and the appearance was visually observed, it was uniform and transparent.
The nonvolatile content (200 ° C./2 hours) of this polyamideimide resin solution was 35% by mass, and the number average molecular weight of the polyamideimide resin was 30,000.

<Example 3>
134.5 g of trimellitic anhydride, 78.8 g of 4,4′-diphenylmethane diisocyanate, 101.8 g of 3,3′-dimethoxybiphenyl-4,4′-diisocyanate, and 585.1 g of dimethylacetamide were added to a thermometer, a stirrer, Then, the mixture was placed in a flask equipped with a cooling tube and gradually heated to 100 ° C. over 2 hours with stirring in a dried nitrogen stream. After heating for 2 hours, the temperature was gradually raised to 140 ° C. while paying attention to the sudden bubbling of carbon dioxide gas generated by the reaction. After heating was started for 6 hours from the start of heating, the reaction was stopped, and polyamide An imide resin solution (resin composition) was obtained. When this polyamideimide resin solution was allowed to stand to room temperature and the appearance was visually observed, it was uniform and transparent.
The nonvolatile content (200 ° C./2 hours) of this polyamideimide resin solution was 32% by mass, and the number average molecular weight of the polyamideimide resin was 20,000.

<Comparative Example 1>
Trimellitic anhydride (175.8 g), 4,4′-diphenylmethane diisocyanate (229.0 g), and dimethylacetamide (494.7 g) were placed in a flask equipped with a thermometer, a stirrer, and a condenser, and stirred in a dry nitrogen stream. The temperature was gradually raised to 120 ° C. over 1 hour. The temperature was kept while paying attention to the sudden foaming of carbon dioxide gas generated by the reaction, and after heating was continued for 8 hours from the start of heating, the reaction was stopped to obtain a polyamideimide resin solution (resin composition). When this polyamideimide resin solution was allowed to stand to room temperature and the appearance was visually observed, it was uniform and transparent.
The nonvolatile content (200 ° C./2 hours) of this polyamideimide resin solution was 42% by mass, and the number average molecular weight of the polyamideimide resin was 15,000.

<Glass transition temperature (Tg)>
The polyamideimide resin composition obtained in each of the above Examples and Comparative Example 1 was applied on a glass plate, preliminarily dried at 80 ° C. for 30 minutes, and then cured at 270 ° C. for 30 minutes. About 10 mg was used as a test piece. About this test piece, Tg was calculated | required from the bending point of the linear expansion curve according to TMA method using the apparatus name "TMA-7100" by Hitachi High-Tech Science. The measurement temperature range at the time of measurement was room temperature to 400 ° C., and the rate of temperature increase was 10 ° C./min.

The measurement results are shown in Table 1.

As can be seen from Table 1, according to the polyamideimide resin composition (Examples 1 to 3) containing a polyamideimide resin having a number average molecular weight of 20,000 or more and dimethylacetamide, a desired Tg of 270 ° C. or more is obtained. Can be realized. On the other hand, when a polyamideimide resin having a number average molecular weight of less than 20,000 is used, it is difficult to realize a desired Tg.
From the above, it can be seen that according to the polyamideimide resin composition according to one embodiment of the present invention, a nonwoven fabric excellent in heat resistance can be efficiently provided. In addition, dimethylacetamide has a low boiling point compared to NMP, which is known as a good solvent for polyamideimide resin, so it has excellent drying properties and is excellent in terms of working environment and environmental safety. Benefit is gained.

Claims (2)

  An amide-imide resin composition for producing a nonwoven fabric, comprising (A) a polyamide-imide resin having a number average molecular weight of 20,000 or more and (B) dimethylacetamide.   The nonwoven fabric formed using the amide imide resin composition for nonwoven fabric manufacture of Claim 1.