WO2020174679A1 - Polyamide acid powder, method of manufacturing polyamide acid powder, and method of manufacturing polyamide acid solution - Google Patents

Polyamide acid powder, method of manufacturing polyamide acid powder, and method of manufacturing polyamide acid solution Download PDF

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Publication number
WO2020174679A1
WO2020174679A1 PCT/JP2019/007917 JP2019007917W WO2020174679A1 WO 2020174679 A1 WO2020174679 A1 WO 2020174679A1 JP 2019007917 W JP2019007917 W JP 2019007917W WO 2020174679 A1 WO2020174679 A1 WO 2020174679A1
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Prior art keywords
polyamic acid
acid powder
mass
polyimide
particles
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PCT/JP2019/007917
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French (fr)
Japanese (ja)
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金澤　親男
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田中　正美
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Priority to PCT/JP2019/007917 priority Critical patent/WO2020174679A1/en
Priority to TW108109459A priority patent/TW202033614A/en
Publication of WO2020174679A1 publication Critical patent/WO2020174679A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J11/00—Recovery or working-up of waste materials
    • C08J11/04—Recovery or working-up of waste materials of polymers
    • C08J11/06—Recovery or working-up of waste materials of polymers without chemical reactions
    • C08J11/08—Recovery or working-up of waste materials of polymers without chemical reactions using selective solvents for polymer components
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J3/00—Processes of treating or compounding macromolecular substances
    • C08J3/12—Powdering or granulating
    • C08J3/14—Powdering or granulating by precipitation from solutions
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/62—Plastics recycling; Rubber recycling

Definitions

  • the present disclosure generally relates to a polyamic acid powder, a method for producing a polyamic acid powder, and a method for producing a polyamic acid solution. More specifically, it relates to a polyamic acid powder containing a plurality of particles precipitated from a treatment liquid in which a waste material containing polyimide and a basic substance are dissolved, a method for producing the polyamic acid powder, and a method for producing the polyamic acid solution.
  • Patent Document 1 describes a polyimide powder which is an aggregate of fine particles containing a polyimide and a polyamic acid. Further, a polyimide solution in which this polyimide powder is dispersed or dissolved in a solvent is described.
  • the present disclosure has been made in view of the above points, and an object thereof is to provide a polyamic acid powder that is easily dissolved in a solvent. Another object of the present disclosure is to provide a method for producing the polyamic acid powder and a polyamic acid solution containing the polyamic acid powder.
  • the polyamic acid powder according to the present disclosure includes a plurality of particles deposited from a treatment liquid containing a polyimide and a basic substance. That is, the polyamic acid powder according to the present disclosure is an aggregate composed of a plurality of particles, and the plurality of particles are obtained by depositing from a treatment liquid in which polyimide and a basic substance are dissolved.
  • the polyamic acid is contained in at least a part of the plurality of particles contained in the polyamic acid powder according to the present disclosure. That is, each particle is constituted by including a polyamic acid.
  • Polyamic acid is a precursor of polyimide. That is, a polyamic acid is imidized by a reaction to produce a polyimide.
  • the polyamic acid powder according to the present disclosure has a water content of 30% by mass or more and 60% by mass or less. That is, the polyamic acid powder according to the present disclosure has a water content of 30% by mass or more and 60% by mass or less based on the total amount of the powder. That is, 30 parts by mass or more and 60 parts by mass or less of water is contained in 100 parts by mass of the polyamic acid powder, and for example, the polyamic acid powder is 30 parts by mass or more and 60 parts by mass of 100 parts by mass of the polyamic acid powder. It contains not more than 40 parts by weight of water and not less than 40 parts by weight and not more than 70 parts by weight of polyamic acid. Water is considered to be contained in each particle.
  • the water content of the polyamic acid powder is less than 30% by mass, it is considered that the amount of polyamic acid contained in each particle is small and the amount of polyimide is large, and the solubility of the polyamic acid powder in a solvent is reduced. There is.
  • the water content of the polyamic acid powder exceeds 60% by mass, it is considered that the amount of polyamic acid contained in each particle is small and the water content is large, and it may be difficult to generate a polyamic acid solution having a high concentration.
  • the particle size (diameter) of each particle included in the polyamic acid powder according to the present disclosure is preferably 10 ⁇ m or less.
  • the particle size of the particles contained in the polyamic acid powder is preferably 1.0 ⁇ m or more. Even if the particle size of the particles contained in the polyamic acid powder is less than 1.0 ⁇ m, there is no particular problem with the solubility, but since the handling property is improved, the particle size of the particles should be 1.0 ⁇ m or more. preferable.
  • the polyamic acid powder according to the present disclosure is composed of a plurality of particles of 1.0 ⁇ m or more and 10 ⁇ m or less, preferably 4.0 ⁇ m or more and 7.0 ⁇ m or less, and the average particle diameter (median diameter D50) of the plurality of particles is 3
  • the thickness is preferably 0.0 ⁇ m or more and 7.0 ⁇ m or less, more preferably 4.0 ⁇ m or more and 6.0 ⁇ m or less.
  • the polyamic acid powder according to the present disclosure may be composed of particles having a diameter of nano level, but it is preferable that the average particle diameter is about 5 ⁇ m because workability (handleability) is deteriorated.
  • the size of the particles containing the polyamic acid can be controlled freely, but the smaller the particle size, the more easily it dissolves in the solvent and the better the workability.
  • the above average particle size and particle size distribution can be measured by a laser diffraction/scattering method using a particle size analyzer (for example, Microtrack MT3300 manufactured by Nikkiso Co., Ltd.).
  • a particle size analyzer for example, Microtrack MT3300 manufactured by Nikkiso Co., Ltd.
  • the polyamic acid powder according to the present disclosure preferably has an alkali metal content of 1 mass% or less derived from the basic substance. That is, the content of the alkali metal derived from the basic substance is preferably 1 part by mass or less based on 100 parts by mass of the polyamic acid powder.
  • the content of the alkali metal derived from the basic substance is 1% or less by weight ratio with respect to the total amount of the polyamic acid powder, the hydrolysis of the particles by the alkali metal is less likely to proceed and It is possible to reduce the decrease in the molecular weight of the polyamic acid.
  • the polyamic acid contained in the particles is less likely to decompose into a low molecular weight compound such as pyromellitic dianhydride or 4,4′-diaminodiphenyl ether, and the storage stability of the polyamic acid powder according to the present disclosure is improved.
  • the property is improved.
  • the lower the content of the alkali metal the more preferable. Therefore, the lower limit of the content of the alkali metal in the polyamic acid powder according to the present disclosure is preferably 0%.
  • the silicone resin may be dissolved in the treatment liquid.
  • particles in which the polyamic acid and other resin are mixed are deposited on the polyamic acid powder.
  • the polyamic acid powder according to the present disclosure can be used alone or as a molding material by mixing with another resin or the like.
  • 10% by mass or more and 30% by weight or less of the above polyamic acid powder is mixed with powder of a tetrafluoroethylene resin having a particle size of 10 ⁇ m or more and 100 ⁇ m or less, and the mixture is 300° C. or more and 360° C. or less, 10 MPa or more and 50 MPa.
  • a sheet or a molded product for example, a sliding component of a rotary bearing
  • the like can be manufactured by heating and pressing under the following conditions.
  • 50% by weight of the polyamic acid powder according to the present disclosure, 40% by weight of thermosetting phenolic resin, and 10% by weight of carbon black are mixed to form a compound, which is 190° C. or higher and 250° C. or lower and 10 MPa or higher.
  • thermosetting phenolic resin 40% by weight of thermosetting phenolic resin, and 10% by weight of carbon black
  • carbon black 50% by weight of the polyamic acid powder according to the present disclosure, 40% by weight of thermosetting phenolic resin, and 10% by weight of carbon black are mixed to form a compound, which is 190° C. or higher and 250° C. or lower and 10 MPa or higher.
  • the particles constituting the polyamic acid powder according to the present disclosure contain polyimide and other decomposition products in addition to polyamic acid. That is, the polyimide contained in the waste material before being hydrolyzed by the treatment liquid contains, for example, a polyimide having a repeating unit represented by the following chemical formula (A). However, the polyamic acid powder according to the present disclosure includes a polyamic acid having a repeating unit represented by the formula (B) and a polyimide having a repeating unit represented by the formula (A), a chemical formula of the formula (C), and the like. It contains particles containing at least one of the decomposition products shown.
  • the polyamic acid powder according to the present disclosure can improve the content of polyimide by heating. It is considered that this is because the polyamic acid contained in the particles was polymerized into polyimide and the imidization of the polyamic acid proceeded. Therefore, the content of the polyimide having the repeating unit represented by the formula (A) is improved in the particles of the polyamic acid powder after heating. Polymerization of polyamic acid starts at around 160°C, and even if the temperature is higher than 230°C, the polymerization is not promoted or the degree of polymerization does not increase, so heating the polyamic acid powder at 160°C to 230°C. Thus, the content of polyimide can be improved.
  • the heating time is not particularly limited, but the above temperature is preferably maintained for 30 minutes or more and 60 minutes or less, which makes it possible to prevent insufficient polymerization of the polyamic acid and to prevent excessive heating. It is possible to avoid (excessive) heating.
  • the polyamic acid powder according to the present disclosure can be heated to obtain a polyimide powder containing many particles having an increased content of polyimide, and the polyimide powder is used as an aggregate for a resin material or a cement material. Can be blended with. Further, after forming a molded product using the polyamic acid powder before heating, by heating this molded product, it is possible to polymerize the polyamic acid in the molded product derived from the particles of the polyamic acid powder. .. In this case, it is possible to obtain a molded product in which the polyimide content is increased and the heat resistance is improved.
  • the polyamic acid powder according to the present disclosure has less deterioration than a varnish made of a monomer, and can be stored for a long time. That is, for example, polyimide having an acid anhydride such as tetracarboxylic dianhydride and a diamine compound such as a diamine as a monomer, after preparing a varnish by polymerizing these monomers into a polyamic acid as a precursor, The precursor is polymerized by heating to produce a polyimide.
  • a varnish containing a polyamic acid produced from a monomer can be stored only for about 90 days after the production of the varnish because the reaction of the polyamic acid is likely to proceed and deteriorate.
  • the polyamic acid solution according to the present disclosure can be prepared immediately before use, it is possible to obtain a varnish of excellent quality in which polyamic acid reaction (imidization) has hardly progressed.
  • the polyimide may be any one as long as it contains an imide bond as a repeating unit in the main chain of the polymer, and examples thereof include an aromatic polyimide in which an aromatic compound is directly linked by an imide bond.
  • Waste material containing polyimide as a raw material for example, industrial waste such as cutting scraps and defective products generated in the process of manufacturing a polyimide film, as long as it contains polyimide such as waste polyimide product, It is preferable to use the cutting scraps and defective products of a polyimide film having a small amount of impurities.
  • At least one of alkali metal and its salt can be used, and for example, a strongly basic substance such as potassium hydroxide or sodium hydroxide can be used.
  • a strongly basic substance such as potassium hydroxide or sodium hydroxide can be used.
  • potassium hydroxide is preferably used because it is possible to obtain a polyamic acid powder that is less discolored from the color of the raw material polyimide.
  • Water can be used as the solvent for the treatment liquid. Further, as the solvent of the treatment liquid, a solution obtained by mixing water and an organic solvent such as glycerin can be used.
  • the treatment liquid can be prepared by mixing the solvent, the basic substance, and the waste material containing the polyimide.
  • the basic substance can be dissolved in a ratio of 25 parts by mass or more and 75 parts by mass or less, and preferably 25 parts by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the solvent.
  • the waste material containing polyimide can be dissolved in a ratio of 40 parts by mass or more and 120 parts by mass or less, preferably 50 parts by mass or more and 90 parts by mass or less with respect to 100 parts by mass of the solvent.
  • the pH of the treatment liquid can be 10-14. Thereby, the waste material containing the polyimide can be favorably dissolved.
  • the temperature of the solvent is 60° C. or higher and 100° C. or lower, preferably 70° C. or higher and 90° C. or lower, and the treatment time (dissolution time) is 90 minutes or longer and 200 minutes or shorter.
  • the waste material containing polyimide may be cut into powder or agitated, if necessary. Thereby, the waste material containing the polyimide can be favorably dissolved.
  • the treatment liquid in which the waste material containing the polyimide and the basic substance are dissolved includes a polyimide (for example, the above formula (A)), a polyamic acid (for example, the above formula (B)), and a compound other than the polyamic acid (for example, And the above formula (C)).
  • the polyimide in the treatment liquid is obtained by dissolving the polyimide contained in the waste material by hydrolysis.
  • the polyamic acid in the treatment liquid is obtained by partially hydrolyzing the polyimide contained in the waste material.
  • the compound other than the polyamic acid is obtained by partially hydrolyzing the polyimide contained in the waste material.
  • an acidic substance is added to this treatment liquid for neutralization to precipitate polyamic acid-containing particles.
  • All or at least a part of the plurality of particles thus deposited contains polyamic acid.
  • a strong acid such as hydrochloric acid or a weak acid such as phosphoric acid can be used as the acidic substance.
  • the addition amount of the acidic substance can be set to 10 to 50 parts by mass, preferably 10 to 40 parts by mass with respect to 100 parts by mass of the solvent of the treatment liquid, which ensures precipitation of particles containing polyamic acid. Can be done.
  • the pH of the treatment liquid can be adjusted to 4 to 6 by adding an acidic substance.
  • the neutralized treatment liquid in which the polyamic acid-containing particles are precipitated is filtered to separate a plurality of solid polyamic acid-containing particles.
  • a filter press or the like can be used for filtration. By this filtration, the solid content of the plurality of particles containing the polyamic acid and the solvent containing the alkali metal derived from the basic substance can be separated.
  • washing with water it is possible to remove (reduce) the amount of alkali metal (derived from the basic substance dissolved in the treatment liquid) remaining after adhering to the plurality of particles containing polyamic acid.
  • Washing with water can be carried out by using a step of putting the filtered solid content in water and stirring it, and repeating this step (for example, 5 to 10 times) until the residual amount of the alkali metal becomes 1% or less. More specifically, for example, a step of mixing 100 parts of water having a water temperature of 60° C. with 50 parts by mass of a plurality of separated polyamic acid-containing particles and stirring for 30 minutes is defined as one step. Washing with water can be performed as if it were performed 6 times.
  • a plurality of particles containing the polyamic acid are dehydrated by drying under reduced pressure or the like and dried to obtain a polyamic acid powder having a water content of 30% by mass or more and 60% by mass or less.
  • the imidization of the polyamic acid tends to proceed, and the solubility of the polyamic acid powder in the solvent may decrease.
  • it may be dried by heating for a while.
  • the polyamic acid solution according to the present disclosure is obtained by dissolving the polyamic acid powder in a solvent.
  • the polyamic acid solution according to the present disclosure can be used as an adhesive or a coating agent. That is, the polyamic acid solution according to the present disclosure can be used as a coating material (varnish) containing a component that forms a film in a solvent, or can be used as a highly heat-resistant adhesive for strongly adhering a metal member. it can.
  • an aprotic polar solvent such as N-methyl-2-pyrrolidone (NMP) or dimethylformamide (DMF) can be used.
  • the polyamic acid solution according to the present disclosure is prepared by blending the solvent in a proportion of 1 part by mass or more and 400 parts by mass or less, preferably 40 parts by mass or more and 300 parts by mass or less, relative to 100 parts by mass of the polyamic acid powder. It can be prepared.
  • the polyamic acid solution according to the present disclosure can be applied to the surface of an article and dried to form a film containing polyimide. That is, the polyamic acid in the polyamic acid solution derived from the polyamic acid powder particles can be imidized (polymerized) to form a film containing polyimide.
  • a coating method of the polyamic acid solution according to the present disclosure spray coating, brush coating, ink jet or the like can be exemplified, although it depends on the viscosity and the like.
  • Polyamic acid solution according to the present disclosure the solvent is evaporated by heating and a film or a lump or the like is formed by the compound in the polyamic acid solution, but this coating or a lump contains more polyimide than before heating. And the heat resistance is improved.
  • Example 1 A polyimide film Kapton (registered trademark) manufactured by Toray-Dupont Co., Ltd. was used as the waste material containing polyimide. Potassium hydroxide (KOH) was used as the basic substance, and 25 parts by mass of potassium hydroxide was dissolved in 40 parts by mass of water. The pH of this aqueous potassium hydroxide solution was 14. Then, 50 parts by mass of the raw material polyimide was mixed and dissolved in 65 parts by mass of the potassium hydroxide aqueous solution to obtain a treatment liquid in which the polyimide was dissolved by alkali hydrolysis. This dissolution was performed at a temperature of 80° C. for 180 minutes.
  • KOH potassium hydroxide
  • an acidic substance was added to the treatment liquid to neutralize the treatment liquid and precipitate particles in the treatment liquid.
  • sulfuric acid was used as the acidic substance, and 40 parts by mass of 62.5% strength sulfuric acid was added to 25 parts by mass of the above potassium hydroxide, followed by stirring for 60 minutes.
  • the treatment liquid in which a plurality of particles containing polyamic acid were deposited was filtered to separate the solid content.
  • the separated solid content was washed with water. Washing with water was repeated 6 times, with one step being a step of adding the filtered solid content to water and stirring at room temperature for 20 minutes. Then, the solid content washed with water was dehydrated under reduced pressure and dried to obtain a polyamic acid powder having a water content of 38%.
  • the particle size of the plurality of particles contained in the obtained polyamic acid powder was in the range of 4.0 ⁇ m or more and 7.0 ⁇ m or less.
  • the content of alkali metal contained in the obtained polyamic acid powder was 1.0% by mass.
  • the water content was measured using a moisture meter "RDMX50” manufactured by Kett Electronics.
  • the alkali metal content was measured with an alkali meter “ALF-1600” manufactured by Toa DKK Co., Ltd.
  • Example 2 A polyamic acid powder was obtained in the same manner as in Example 1 except that the conditions of the dehydration under reduced pressure were changed to obtain the polyamic acid powder having a water content of 30 mass %. Further, in the same manner as in Example 1, 50 parts by mass of the obtained polyamic acid powder and 100 parts by mass of dimethylformamide were dissolved while heating at 40° C. to obtain a polyamic acid solution. ..
  • Example 3 A polyamic acid powder was obtained in the same manner as in Example 1 except that the conditions of the dehydration under reduced pressure were changed to obtain the polyamic acid powder having a water content of 50% by mass. Further, in the same manner as in Example 1, 50 parts by mass of the obtained polyamic acid powder and 100 parts by mass of dimethylformamide were dissolved while heating at 40° C. to obtain a polyamic acid solution. ..
  • Example 4 A polyamic acid powder was obtained in the same manner as in Example 1 except that the conditions of dehydration under reduced pressure were changed to obtain a polyamic acid powder having a water content of 60% by mass. Further, in the same manner as in Example 1, 50 parts by mass of the obtained polyamic acid powder and 100 parts by mass of dimethylformamide were dissolved while heating at 40° C. to obtain a polyamic acid solution. ..
  • Example 5 Polyamic acid was obtained in the same manner as in Example 1 except that sodium hydroxide was used as the basic substance instead of potassium hydroxide.
  • the particle size of the plurality of particles contained in the obtained polyamic acid powder was in the range of 4.0 ⁇ m or more and 7.0 ⁇ m or less.
  • the content of alkali metal contained in the obtained polyamic acid powder was 1.0% by mass.
  • Example 2 The polyamic acid powder of Example 1 was heated at 100° C. to evaporate the water to obtain a polyamic acid powder having a water content of 0.5% by mass. 50 parts by mass of the obtained polyamic acid powder and 100 parts by mass of dimethylformamide were dissolved while heating at 40° C. to obtain a polyamic acid solution.
  • the polyamic acid powder according to the first aspect is a polyamic acid powder containing a plurality of particles precipitated from the treatment liquid containing the polyimide and the basic substance. At least a part of the plurality of particles contains a polyamic acid.
  • the water content is 30% by mass or more and 60% by mass or less.
  • the polyamic acid contained in each particle is less likely to be imidized by heating during drying and is easily dissolved in a solvent.
  • the polyamic acid powder according to the second aspect is obtained by dissolving the waste material containing the polyimide in the treatment liquid in the first aspect.
  • each particle has a particle size of 10 ⁇ m or less.
  • the content of the alkali metal derived from the basic substance is 1.0% by mass or less.
  • the polyamic acid powder according to any one of the first to fourth aspects is dissolved in a solvent.
  • particles containing polyamic acid are precipitated by mixing a treatment liquid in which waste material containing polyimide and a basic substance are dissolved with an acidic substance. The particles are dried until the water content is 30% by mass or more and 60% by mass or less.
  • the polyamic acid contained in each particle is less likely to be imidized by heating during drying and is easily dissolved in a solvent.

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  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
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Abstract

Provided is a polyamide acid powder that easily dissolves in a solvent. The polyamide acid powder of the current disclosure is a polyamide acid powder containing a plurality of particles precipitated from a processing solution that includes a polyimide and a basic substance. At least some of said plurality of particles includes a polyamide acid. The percentage of water content is 30% to 60% by weight.

Description

ポリアミド酸粉体、ポリアミド酸粉体の製造方法、ポリアミド酸溶液の製造方法Polyamic acid powder, method for producing polyamic acid powder, method for producing polyamic acid solution
　本開示は、一般に、ポリアミド酸粉体、ポリアミド酸粉体の製造方法、ポリアミド酸溶液の製造方法に関する。より詳細には、ポリイミドを含む廃材及び塩基性物質が溶解した処理液から析出した複数の粒子を含むポリアミド酸粉体、ポリアミド酸粉体の製造方法、ポリアミド酸溶液の製造方法に関する。 The present disclosure generally relates to a polyamic acid powder, a method for producing a polyamic acid powder, and a method for producing a polyamic acid solution. More specifically, it relates to a polyamic acid powder containing a plurality of particles precipitated from a treatment liquid in which a waste material containing polyimide and a basic substance are dissolved, a method for producing the polyamic acid powder, and a method for producing the polyamic acid solution.
　特許文献１には、ポリイミドとポリアミド酸とを含有する微粒子の集合体であるポリイミド粉体が記載されている。また、このポリイミド粉体が溶媒に分散乃至溶解したポリイミド溶液が記載されている。 Patent Document 1 describes a polyimide powder which is an aggregate of fine particles containing a polyimide and a polyamic acid. Further, a polyimide solution in which this polyimide powder is dispersed or dissolved in a solvent is described.
特許第５６９５６７５号公報Japanese Patent No. 5695675
　しかし、特許文献１に記載のポリイミド粉体では、溶媒に溶けにくく、溶け残りが生じたり、溶けるのに長時間を要することがあった。 However, with the polyimide powder described in Patent Document 1, it was difficult to dissolve in the solvent, and there was a case where undissolved residue was generated or it took a long time to dissolve.
　本開示は、上記の点に鑑みてなされたものであり、溶剤に溶解しやすいポリアミド酸粉体を提供することを目的とするものである。また本開示は、上記ポリアミド酸粉体の製造方法及び上記ポリアミド酸粉体を含むポリアミド酸溶液を提供することを目的とするものである。 The present disclosure has been made in view of the above points, and an object thereof is to provide a polyamic acid powder that is easily dissolved in a solvent. Another object of the present disclosure is to provide a method for producing the polyamic acid powder and a polyamic acid solution containing the polyamic acid powder.
　（実施形態）
　（ポリアミド酸粉体について）
　本開示に係るポリアミド酸粉体は、ポリイミド及び塩基性物質を含有する処理液から析出した複数の粒子を含む。すなわち、本開示に係るポリアミド酸粉体は、複数の粒子からなる集合体であって、この複数の粒子は、ポリイミド及び塩基性物質が溶解した処理液から析出して得られる。 (Embodiment)
(About polyamic acid powder)
The polyamic acid powder according to the present disclosure includes a plurality of particles deposited from a treatment liquid containing a polyimide and a basic substance. That is, the polyamic acid powder according to the present disclosure is an aggregate composed of a plurality of particles, and the plurality of particles are obtained by depositing from a treatment liquid in which polyimide and a basic substance are dissolved.
　本開示に係るポリアミド酸粉体に含まれる複数の粒子の少なくとも一部にポリアミド酸が含まれている。すなわち、ポリアミド酸を含んで各粒子が構成されている。ポリアミド酸はポリイミドの前駆体である。すなわち、ポリアミド酸が反応によりイミド化することによりポリイミドが生成される。 The polyamic acid is contained in at least a part of the plurality of particles contained in the polyamic acid powder according to the present disclosure. That is, each particle is constituted by including a polyamic acid. Polyamic acid is a precursor of polyimide. That is, a polyamic acid is imidized by a reaction to produce a polyimide.
　そして、本開示に係るポリアミド酸粉体は、含水率が３０質量％以上６０質量％以下である。すなわち、本開示に係るポリアミド酸粉体は粉体全量に対して３０質量％以上６０質量％以下の含水率を有している。つまり、ポリアミド酸粉体１００質量部のうち、３０質量部以上６０質量部以下の水分を含んでおり、例えば、ポリアミド酸粉体は、ポリアミド酸粉体１００質量部のうち、３０質量部以上６０質量部以下の水分を含み、４０質量部以上７０質量部以下のポリアミド酸を含んでいる。水分は各粒子に含有されていると考えられる。 The polyamic acid powder according to the present disclosure has a water content of 30% by mass or more and 60% by mass or less. That is, the polyamic acid powder according to the present disclosure has a water content of 30% by mass or more and 60% by mass or less based on the total amount of the powder. That is, 30 parts by mass or more and 60 parts by mass or less of water is contained in 100 parts by mass of the polyamic acid powder, and for example, the polyamic acid powder is 30 parts by mass or more and 60 parts by mass of 100 parts by mass of the polyamic acid powder. It contains not more than 40 parts by weight of water and not less than 40 parts by weight and not more than 70 parts by weight of polyamic acid. Water is considered to be contained in each particle.
　ポリアミド酸粉体の含水率が３０質量％未満であると、各粒子に含まれるポリアミド酸の量が少なくてポリイミドの量が多いと考えれられ、ポリアミド酸粉体の溶剤に対する溶解性が低下することがある。ポリアミド酸粉体の含水率が６０質量％を超えると、各粒子に含まれるポリアミド酸の量が少なくて水分が多いと考えれられ、高濃度のポリアミド酸溶液を生成しにくくなることがある。 When the water content of the polyamic acid powder is less than 30% by mass, it is considered that the amount of polyamic acid contained in each particle is small and the amount of polyimide is large, and the solubility of the polyamic acid powder in a solvent is reduced. There is. When the water content of the polyamic acid powder exceeds 60% by mass, it is considered that the amount of polyamic acid contained in each particle is small and the water content is large, and it may be difficult to generate a polyamic acid solution having a high concentration.
　本開示に係るポリアミド酸粉体に含まれる各粒子の粒径（直径）は１０μｍ以下であることが好ましい。ポリアミド酸粉体に含まれる各粒子の粒径が１０μｍを超えると、粒子が溶剤に溶解しにくくなって、ポリアミド酸粉体の溶剤に対する溶解性が低下することがある。ポリアミド酸粉体に含まれる粒子の粒径は１．０μｍ以上であることが好ましい。ポリアミド酸粉体に含まれる粒子の粒径が１．０μｍ未満であっても、溶解性に特に問題がないが、取扱性が向上するため、粒子の粒径は１．０μｍ以上であることが好ましい。 The particle size (diameter) of each particle included in the polyamic acid powder according to the present disclosure is preferably 10 μm or less. When the particle diameter of each particle contained in the polyamic acid powder exceeds 10 μm, the particles are difficult to dissolve in the solvent, and the solubility of the polyamic acid powder in the solvent may decrease. The particle size of the particles contained in the polyamic acid powder is preferably 1.0 μm or more. Even if the particle size of the particles contained in the polyamic acid powder is less than 1.0 μm, there is no particular problem with the solubility, but since the handling property is improved, the particle size of the particles should be 1.0 μm or more. preferable.
　例えば、本開示に係るポリアミド酸粉体は、１．０μｍ以上１０μｍ以下、好ましくは４．０μｍ以上７．０μｍ以下の複数の粒子からなり、複数の粒子の平均粒径（メジアン径Ｄ５０）が３．０μｍ以上７．０μｍ以下、好ましくは４．０μｍ以上６．０μｍ以下であることが好ましい。本開示に係るポリアミド酸粉体は、直径がナノレベルの粒子で構成されていてもよいが、作業性（取扱性）が低下するために、平均粒径が約５μｍであることが好ましい。ポリアミド酸を含む粒子の大きさは、自在にコントロール可能であるが、粒径が小さいほど、溶剤に溶けやすくて作業性がよい。 For example, the polyamic acid powder according to the present disclosure is composed of a plurality of particles of 1.0 μm or more and 10 μm or less, preferably 4.0 μm or more and 7.0 μm or less, and the average particle diameter (median diameter D50) of the plurality of particles is 3 The thickness is preferably 0.0 μm or more and 7.0 μm or less, more preferably 4.0 μm or more and 6.0 μm or less. The polyamic acid powder according to the present disclosure may be composed of particles having a diameter of nano level, but it is preferable that the average particle diameter is about 5 μm because workability (handleability) is deteriorated. The size of the particles containing the polyamic acid can be controlled freely, but the smaller the particle size, the more easily it dissolves in the solvent and the better the workability.
　なお、上記の平均粒径及び粒度分布は、粒度分析計（例えば、日機装株式会社製のマイクロトラックＭＴ３３００）を用いたレーザー回折・散乱法などにより測定することができる。 The above average particle size and particle size distribution can be measured by a laser diffraction/scattering method using a particle size analyzer (for example, Microtrack MT3300 manufactured by Nikkiso Co., Ltd.).
　本開示に係るポリアミド酸粉体は、前記塩基性物質に由来するアルカリ金属の含有量が１質量％以下であることが好ましい。すなわち、塩基性物質に由来するアルカリ金属の含有量が、ポリアミド酸粉体１００質量部に対して１質量部以下であることが好ましい。塩基性物質に由来するアルカリ金属の含有量が、ポリアミド酸粉体の全量に対して重量比で１％以下とすることにより、アルカリ金属による粒子の加水分解が進行しにくくなり、粒子に含まれているポリアミド酸の低分子量化されることを少なくすることができる。例えば、粒子に含まれているポリアミド酸が、ピロメリット酸二無水物又は４，４’－ジアミノジフェニルエーテルなどの低分子化合物にまで分解が進みにくくなり、本開示に係るポリアミド酸粉体の保存安定性が向上する。なお、アルカリ金属の含有量は少ないほど好ましいので、本開示に係るポリアミド酸粉体のアルカリ金属の含有量の下限は０％であることが好ましい。 The polyamic acid powder according to the present disclosure preferably has an alkali metal content of 1 mass% or less derived from the basic substance. That is, the content of the alkali metal derived from the basic substance is preferably 1 part by mass or less based on 100 parts by mass of the polyamic acid powder. When the content of the alkali metal derived from the basic substance is 1% or less by weight ratio with respect to the total amount of the polyamic acid powder, the hydrolysis of the particles by the alkali metal is less likely to proceed and It is possible to reduce the decrease in the molecular weight of the polyamic acid. For example, the polyamic acid contained in the particles is less likely to decompose into a low molecular weight compound such as pyromellitic dianhydride or 4,4′-diaminodiphenyl ether, and the storage stability of the polyamic acid powder according to the present disclosure is improved. The property is improved. It should be noted that the lower the content of the alkali metal, the more preferable. Therefore, the lower limit of the content of the alkali metal in the polyamic acid powder according to the present disclosure is preferably 0%.
　なお、処理液にはポリイミド及び塩基性物質の他に、他の樹脂が溶解していてもよい。例えば、シリコーン樹脂が処理液に溶解していてもよい。この場合、ポリアミド酸粉体にはポリアミド酸と他の樹脂とが混在した粒子が析出される。 In addition to polyimide and basic substances, other resins may be dissolved in the processing liquid. For example, the silicone resin may be dissolved in the treatment liquid. In this case, particles in which the polyamic acid and other resin are mixed are deposited on the polyamic acid powder.
　本開示に係るポリアミド酸粉体は、単独であるいは他の樹脂等と混合することにより成形材料として用いることができる。例えば、粒径１０μｍ以上１００μｍ以下の四フッ化エチレン樹脂の粉末に対して１０質量％以上３０重量％以下の上記ポリアミド酸粉体を混合し、この混合物を３００℃以上３６０℃以下、１０ＭＰａ以上５０ＭＰａ以下の条件で加熱加圧成形することによって、シート又は成形品（例えば、回転軸受の摺動部品）などを製造することができる。 The polyamic acid powder according to the present disclosure can be used alone or as a molding material by mixing with another resin or the like. For example, 10% by mass or more and 30% by weight or less of the above polyamic acid powder is mixed with powder of a tetrafluoroethylene resin having a particle size of 10 μm or more and 100 μm or less, and the mixture is 300° C. or more and 360° C. or less, 10 MPa or more and 50 MPa. A sheet or a molded product (for example, a sliding component of a rotary bearing) or the like can be manufactured by heating and pressing under the following conditions.
　また、本開示に係るポリアミド酸粉体の５０重量％と、熱硬化性フェノール樹脂４０重量％と、カーボンブラック１０重量％とを混合してコンパウンド化し、これを１９０℃以上２５０℃以下、１０ＭＰａ以上２０ＭＰａ以下、３０分間以上４５分間以下の条件で加熱加圧成形することによって、耐熱性電材部品、自動車部品、ガラスビンのネジ部の型枠成形などに利用できる成形品を製造することができる。また、本開示に係るポリアミド酸粉体と炭素繊維（カーボンファイバー）と四フッ化エチレン粉末を混合して加熱加圧成形することによって、耐熱性及び耐衝撃性を有する成形品を製造することができる。 Further, 50% by weight of the polyamic acid powder according to the present disclosure, 40% by weight of thermosetting phenolic resin, and 10% by weight of carbon black are mixed to form a compound, which is 190° C. or higher and 250° C. or lower and 10 MPa or higher. By heat and pressure molding under the conditions of 20 MPa or less and 30 minutes or more and 45 minutes or less, it is possible to produce a molded product that can be used for molding heat-resistant electric material parts, automobile parts, molds of screw parts of glass bottles, and the like. Further, a molded product having heat resistance and impact resistance can be manufactured by mixing the polyamic acid powder, the carbon fiber (carbon fiber), and the tetrafluoroethylene powder according to the present disclosure and heating and pressing the mixture. it can.
　本開示に係るポリアミド酸粉体を構成する粒子は、ポリアミド酸の他に、ポリイミドと、その他の分解物を含有するものである。すなわち、処理液で加水分解する前に廃材に含まれているポリイミドは、例えば、下記化学式の式（Ａ）で示す繰り返し単位を有するポリイミドを含んでいる。しかし、本開示に係るポリアミド酸粉体は、式（Ｂ）で示す繰り返し単位を有するポリアミド酸を含有し、かつ式（Ａ）で示す繰り返し単位を有するポリイミドと、式（Ｃ）の化学式等で示す分解物との少なくとも一方を含有する粒子を含むものである。 The particles constituting the polyamic acid powder according to the present disclosure contain polyimide and other decomposition products in addition to polyamic acid. That is, the polyimide contained in the waste material before being hydrolyzed by the treatment liquid contains, for example, a polyimide having a repeating unit represented by the following chemical formula (A). However, the polyamic acid powder according to the present disclosure includes a polyamic acid having a repeating unit represented by the formula (B) and a polyimide having a repeating unit represented by the formula (A), a chemical formula of the formula (C), and the like. It contains particles containing at least one of the decomposition products shown.
Figure JPOXMLDOC01-appb-C000001
Figure JPOXMLDOC01-appb-C000001
　本開示に係るポリアミド酸粉体は、加熱により、ポリイミドの含有量を向上させることができる。これは、粒子中に含まれているポリアミド酸がポリイミドへと重合し、ポリアミド酸のイミド化が進行するためと考えられる。従って、加熱後のポリアミド酸粉体の粒子は、式（Ａ）で示す繰り返し単位を有するポリイミドの含有率が向上するものである。ポリアミド酸の重合は１６０℃付近から開始され、また、２３０℃以上にしても重合が促進されたり重合度が高くなったりすることが少ないため、１６０℃以上２３０℃以下でポリアミド酸粉体を加熱してポリイミドの含有量を向上させることができる。また、上記の加熱の際の時間は、特に限定されないが、上記の温度が３０分間以上６０分間以下保持されるのが好ましく、これにより、ポリアミド酸の重合不足が発生しにくくなり、また余分な（過剰な）加熱が行われないようにすることができる。このように本開示に係るポリアミド酸粉体は、加熱により、ポリイミドの含有量が増加した粒子を多く含むポリイミド粉体を得ることができ、このポリイミド粉体を骨材として樹脂材料又はセメント材料などに配合することができる。また、加熱前のポリアミド酸粉体を用いて成形品を形成した後、この成形品を加熱することによって、ポリアミド酸粉体の粒子を由来とする成形品中のポリアミド酸を重合することができる。この場合、ポリイミドの含有量が増加して耐熱性が向上した成形品を得ることができる。 The polyamic acid powder according to the present disclosure can improve the content of polyimide by heating. It is considered that this is because the polyamic acid contained in the particles was polymerized into polyimide and the imidization of the polyamic acid proceeded. Therefore, the content of the polyimide having the repeating unit represented by the formula (A) is improved in the particles of the polyamic acid powder after heating. Polymerization of polyamic acid starts at around 160°C, and even if the temperature is higher than 230°C, the polymerization is not promoted or the degree of polymerization does not increase, so heating the polyamic acid powder at 160°C to 230°C. Thus, the content of polyimide can be improved. The heating time is not particularly limited, but the above temperature is preferably maintained for 30 minutes or more and 60 minutes or less, which makes it possible to prevent insufficient polymerization of the polyamic acid and to prevent excessive heating. It is possible to avoid (excessive) heating. Thus, the polyamic acid powder according to the present disclosure can be heated to obtain a polyimide powder containing many particles having an increased content of polyimide, and the polyimide powder is used as an aggregate for a resin material or a cement material. Can be blended with. Further, after forming a molded product using the polyamic acid powder before heating, by heating this molded product, it is possible to polymerize the polyamic acid in the molded product derived from the particles of the polyamic acid powder. .. In this case, it is possible to obtain a molded product in which the polyimide content is increased and the heat resistance is improved.
　そして、本開示に係るポリアミド酸粉体は、モノマーから作製されるワニスに比べて劣化が少なく、長期保存が可能である。すなわち、例えば、テトラカルボン酸二無水物などの酸無水物とジアミン等のジアミン系化合物とをモノマーとするポリイミドは、これらのモノマーを前駆体であるポリアミド酸に重合してワニスを調製した後、加熱により前駆体を重合してポリイミドを生成する。しかし、モノマーから作製されるポリアミド酸を含むワニスは、ポリアミド酸の反応が進みやすくて劣化しやすいため、ワニスの製造から９０日程度しか保存できない。しかし、本開示に係るポリアミド酸粉体の状態ではポリアミド酸の反応が進みにくく、９０日間以上の長期保存が可能である。したがって、本開示に係るポリアミド酸溶液は、使用直前に調製可能であるため、ポリアミド酸の反応（イミド化）がほとんど進んでいない品質に優れたワニスとすることが可能である。 The polyamic acid powder according to the present disclosure has less deterioration than a varnish made of a monomer, and can be stored for a long time. That is, for example, polyimide having an acid anhydride such as tetracarboxylic dianhydride and a diamine compound such as a diamine as a monomer, after preparing a varnish by polymerizing these monomers into a polyamic acid as a precursor, The precursor is polymerized by heating to produce a polyimide. However, a varnish containing a polyamic acid produced from a monomer can be stored only for about 90 days after the production of the varnish because the reaction of the polyamic acid is likely to proceed and deteriorate. However, in the state of the polyamic acid powder according to the present disclosure, it is difficult for the polyamic acid reaction to proceed, and long-term storage of 90 days or more is possible. Therefore, since the polyamic acid solution according to the present disclosure can be prepared immediately before use, it is possible to obtain a varnish of excellent quality in which polyamic acid reaction (imidization) has hardly progressed.
　（ポリアミド酸粉体の製造方法について）
　本開示に係るポリアミド酸粉体の製造方法は、ポリイミドを含む廃材及び塩基性物質が溶解した処理液と酸性物質とを混合することにより、ポリアミド酸を含有する粒子を析出させる。この後、含水率が３０質量％以上６０質量％以下となるまで複数の前記粒子を乾燥させる。 (About manufacturing method of polyamic acid powder)
In the method for producing a polyamic acid powder according to the present disclosure, particles containing polyamic acid are deposited by mixing a treatment liquid in which a waste material containing polyimide and a basic substance are dissolved with an acidic substance. Then, the plurality of particles are dried until the water content becomes 30% by mass or more and 60% by mass or less.
　ポリイミドは、ポリマーの主鎖に繰り返し単位としてイミド結合を含むものであればよく、例えば、芳香族化合物が直接イミド結合で連結された芳香族ポリイミドなどを挙げることができる。原料となるポリイミドを含む廃材は、例えば、ポリイミドフィルムを製造する過程で発生する裁断屑及び不良品などの産業廃棄物、ポリイミド製品の廃棄物等のポリイミドを含むものであれば、何でもよいが、不純物の少ないポリイミドフィルムの裁断屑及び不良品を用いるのが好ましい。 The polyimide may be any one as long as it contains an imide bond as a repeating unit in the main chain of the polymer, and examples thereof include an aromatic polyimide in which an aromatic compound is directly linked by an imide bond. Waste material containing polyimide as a raw material, for example, industrial waste such as cutting scraps and defective products generated in the process of manufacturing a polyimide film, as long as it contains polyimide such as waste polyimide product, It is preferable to use the cutting scraps and defective products of a polyimide film having a small amount of impurities.
　塩基性物質としては、アルカリ金属又はその塩の少なくとも一方を用いることができ、例えば、水酸化カリウム又は水酸化ナトリウムなどの強塩基性物質を用いることができる。特に、原料のポリイミドの色からの変色が少ないポリアミド酸粉体を得ることができるため、水酸化カリウムを使用することが好ましい。 As the basic substance, at least one of alkali metal and its salt can be used, and for example, a strongly basic substance such as potassium hydroxide or sodium hydroxide can be used. In particular, potassium hydroxide is preferably used because it is possible to obtain a polyamic acid powder that is less discolored from the color of the raw material polyimide.
　処理液の溶媒としては水を使用することができる。また処理液の溶媒としては、水と、グリセリン等の有機溶媒とを混合した溶液を用いることができる。 Water can be used as the solvent for the treatment liquid. Further, as the solvent of the treatment liquid, a solution obtained by mixing water and an organic solvent such as glycerin can be used.
　そして、溶媒と塩基性物質とポリイミドを含む廃材とを混合することにより処理液を調製することができる。ここで、塩基性物質は溶媒１００質量部に対して２５質量部以上７５質量部以下、好ましくは２５質量部以上４０質量部以下の割合で溶解させることができる。またポリイミドを含む廃材は溶媒１００質量部に対して４０質量部以上１２０質量部以下、好ましくは５０質量部以上９０質量部以下の割合で溶解させることができる。また、処理液のｐＨは１０～１４にすることができる。これにより、ポリイミドを含む廃材の溶解を良好に行うことができる。 Then, the treatment liquid can be prepared by mixing the solvent, the basic substance, and the waste material containing the polyimide. Here, the basic substance can be dissolved in a ratio of 25 parts by mass or more and 75 parts by mass or less, and preferably 25 parts by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the solvent. The waste material containing polyimide can be dissolved in a ratio of 40 parts by mass or more and 120 parts by mass or less, preferably 50 parts by mass or more and 90 parts by mass or less with respect to 100 parts by mass of the solvent. The pH of the treatment liquid can be 10-14. Thereby, the waste material containing the polyimide can be favorably dissolved.
　処理液を調製するにあたって、溶媒の温度は６０℃以上１００℃以下、好ましくは、７０℃以上９０℃以下にするのが好ましく、また処理時間（溶解時間）は９０分間以上２００分間以下とすることができる。また、必要に応じて、ポりイミドを含む廃材を粉末に裁断したり、撹拌を行ったりしてもよい。これにより、ポリイミドを含む廃材の溶解を良好に行うことができる。 In preparing the treatment liquid, the temperature of the solvent is 60° C. or higher and 100° C. or lower, preferably 70° C. or higher and 90° C. or lower, and the treatment time (dissolution time) is 90 minutes or longer and 200 minutes or shorter. You can In addition, the waste material containing polyimide may be cut into powder or agitated, if necessary. Thereby, the waste material containing the polyimide can be favorably dissolved.
　ポリイミドを含む廃材と塩基性物質とが溶解した処理液には、ポリイミド（例えば、上記式（Ａ））と、ポリアミド酸（例えば、上記式（Ｂ））と、ポリアミド酸以外の化合物（例えば、上記式（Ｃ））とが含有されている。処理液中のポリイミドは、廃材に含まれていたポリイミドが加水分解により溶解して得られる。処理液中のポリアミド酸は、廃材に含まれていたポリイミドの一部が加水分解されて得られる。ポリアミド酸以外の化合物は、廃材に含まれていたポリイミドの一部が加水分解されて得られる。 The treatment liquid in which the waste material containing the polyimide and the basic substance are dissolved includes a polyimide (for example, the above formula (A)), a polyamic acid (for example, the above formula (B)), and a compound other than the polyamic acid (for example, And the above formula (C)). The polyimide in the treatment liquid is obtained by dissolving the polyimide contained in the waste material by hydrolysis. The polyamic acid in the treatment liquid is obtained by partially hydrolyzing the polyimide contained in the waste material. The compound other than the polyamic acid is obtained by partially hydrolyzing the polyimide contained in the waste material.
　次に、ポリイミドを含む廃材と塩基性物質とが溶解した処理液を室温程度まで冷却した後、この処理液に酸性物質を添加して中和処理し、ポリアミド酸を含む粒子を析出させる。このようにして析出した複数の粒子の全部又は少なくとも一部はポリアミド酸を含有している。ここで、酸性物質としては塩酸などの強酸又はリン酸などの弱酸を用いることができる。酸性物質の添加量は上記処理液の溶媒１００質量部に対して１０～５０質量部、好ましくは１０～４０質量部の割合とすることができ、これにより、ポリアミド酸を含む粒子の析出を確実に行うことができる。また、酸性物質の添加により、処理液のｐＨを４～６にすることができる。 Next, after cooling the treatment liquid in which the waste material containing polyimide and the basic substance are dissolved to about room temperature, an acidic substance is added to this treatment liquid for neutralization to precipitate polyamic acid-containing particles. All or at least a part of the plurality of particles thus deposited contains polyamic acid. Here, a strong acid such as hydrochloric acid or a weak acid such as phosphoric acid can be used as the acidic substance. The addition amount of the acidic substance can be set to 10 to 50 parts by mass, preferably 10 to 40 parts by mass with respect to 100 parts by mass of the solvent of the treatment liquid, which ensures precipitation of particles containing polyamic acid. Can be done. Further, the pH of the treatment liquid can be adjusted to 4 to 6 by adding an acidic substance.
　次に、ポリアミド酸を含む粒子が析出した上記中和後の処理液を濾過し、固形分のポリアミド酸を含む複数の粒子を分離する。濾過はフィルタープレスなどを用いることができる。この濾過により、ポリアミド酸を含む複数の粒子の固形分と塩基性物質に由来するアルカリ金属を含む溶媒とを分離することができる。 Next, the neutralized treatment liquid in which the polyamic acid-containing particles are precipitated is filtered to separate a plurality of solid polyamic acid-containing particles. A filter press or the like can be used for filtration. By this filtration, the solid content of the plurality of particles containing the polyamic acid and the solvent containing the alkali metal derived from the basic substance can be separated.
　次に、分離して得られたポリアミド酸を含む複数の粒子を水洗する。この水洗により、ポリアミド酸を含む複数の粒子に付着等して残留しているアルカリ金属（上記処理液に溶解していた塩基性物質に由来する）を除去（減量）することができる。水洗は、濾過した固形分を水に入れて撹拌する工程を一工程として、この工程をアルカリ金属の残留量が１％以下になるまで（例えば５～１０回）繰り返して行うことができる。より具体的には、例えば、分離したポリアミド酸を含む複数の粒子の５０質量部に対して水温６０℃の水を１００リットルの割合で混合し、３０分間撹拌する工程を一工程とし、これを６回行うようにして水洗を行うことができる。 Next, the separated multiple particles containing polyamic acid are washed with water. By this washing with water, it is possible to remove (reduce) the amount of alkali metal (derived from the basic substance dissolved in the treatment liquid) remaining after adhering to the plurality of particles containing polyamic acid. Washing with water can be carried out by using a step of putting the filtered solid content in water and stirring it, and repeating this step (for example, 5 to 10 times) until the residual amount of the alkali metal becomes 1% or less. More specifically, for example, a step of mixing 100 parts of water having a water temperature of 60° C. with 50 parts by mass of a plurality of separated polyamic acid-containing particles and stirring for 30 minutes is defined as one step. Washing with water can be performed as if it were performed 6 times.
　この後、ポリアミド酸を含む複数の粒子を減圧等により脱水して乾燥し、含水率が３０質量％以上６０質量％以下のポリアミド酸粉体を得ることができる。ここで、ポリアミド酸を含む複数の粒子を加熱しないで含水率を調整することが好ましい。加熱すると、ポリアミド酸のイミド化が進みやすくなって、ポリアミド酸粉体の溶剤への溶解性が低下することがある。ただし、ポリアミド酸のイミド化が進みにくい温度であれば、多少、加熱して乾燥してもよい。 After that, a plurality of particles containing the polyamic acid are dehydrated by drying under reduced pressure or the like and dried to obtain a polyamic acid powder having a water content of 30% by mass or more and 60% by mass or less. Here, it is preferable to adjust the water content without heating the plurality of particles containing the polyamic acid. When heated, the imidization of the polyamic acid tends to proceed, and the solubility of the polyamic acid powder in the solvent may decrease. However, at a temperature at which the imidization of the polyamic acid does not easily proceed, it may be dried by heating for a while.
　（ポリアミド酸溶液について）
　本開示に係るポリアミド酸溶液は、上記ポリアミド酸粉体を溶剤に溶解させることによって得られる。本開示に係るポリアミド酸溶液は、接着剤又はコーティング剤などとして使用することができる。すなわち、本開示に係るポリアミド酸溶液は、溶剤に被膜となる成分を含有する塗料（ワニス）として用いることができ、又は金属部材を強固に接着するための耐熱性の高い接着剤として用いることができる。ポリアミド酸溶液の溶剤としては、Ｎ－メチル－２－ピロリドン（ＮＭＰ）又はジメチルホルムアミド（ＤＭＦ）などの非プロトン性極性溶媒を用いることができる。本開示に係るポリアミド酸溶液は、ポリアミド酸粉体１００質量部に対して１質量部以上４００質量部以下の割合、好ましくは、４０質量部以上３００質量部以下の割合で溶剤を配合することにより調製することができる。 (About polyamic acid solution)
The polyamic acid solution according to the present disclosure is obtained by dissolving the polyamic acid powder in a solvent. The polyamic acid solution according to the present disclosure can be used as an adhesive or a coating agent. That is, the polyamic acid solution according to the present disclosure can be used as a coating material (varnish) containing a component that forms a film in a solvent, or can be used as a highly heat-resistant adhesive for strongly adhering a metal member. it can. As the solvent for the polyamic acid solution, an aprotic polar solvent such as N-methyl-2-pyrrolidone (NMP) or dimethylformamide (DMF) can be used. The polyamic acid solution according to the present disclosure is prepared by blending the solvent in a proportion of 1 part by mass or more and 400 parts by mass or less, preferably 40 parts by mass or more and 300 parts by mass or less, relative to 100 parts by mass of the polyamic acid powder. It can be prepared.
　本開示に係るポリアミド酸溶液は、物品の表面に塗布して乾燥させることにより、ポリイミドを含む被膜を形成することができる。すなわち、ポリアミド酸粉体の粒子を由来とするポリアミド酸溶液中のポリアミド酸がイミド化（重合）してポリイミドを含む被膜を形成することができる。本開示に係るポリアミド酸溶液の塗布方法としては、粘度等によっても異なるが、スプレー塗布又は刷毛塗り又はインクジェットなどを例示することができる。本開示に係るポリアミド酸溶液は、加熱することによって溶剤が蒸発すると共にポリアミド酸溶液中の化合物で被膜又は塊状物などが生成されるが、この被膜又は塊状物は加熱前よりもポリイミドの含有量が増加して耐熱性が向上している。 The polyamic acid solution according to the present disclosure can be applied to the surface of an article and dried to form a film containing polyimide. That is, the polyamic acid in the polyamic acid solution derived from the polyamic acid powder particles can be imidized (polymerized) to form a film containing polyimide. As a coating method of the polyamic acid solution according to the present disclosure, spray coating, brush coating, ink jet or the like can be exemplified, although it depends on the viscosity and the like. Polyamic acid solution according to the present disclosure, the solvent is evaporated by heating and a film or a lump or the like is formed by the compound in the polyamic acid solution, but this coating or a lump contains more polyimide than before heating. And the heat resistance is improved.
　（実施例１）
　ポリイミドを含む廃材としては、東レ・デュポン株式会社製のポリイミドフィルムカプトン（登録商標）を用いた。塩基性物質としては水酸化カリウム（ＫＯＨ）を用い、水４０質量部に対して水酸化カリウム２５質量部を溶解させた。この水酸化カリウム水溶液のｐＨは１４であった。そして、上記水酸化カリウム水溶液６５質量部に対して原料のポリイミド５０質量部を混合して溶解することによって、ポリイミドがアルカリ加水分解により溶解した処理液を得た。この溶解は温度が８０℃で１８０分間の条件で行った。 (Example 1)
A polyimide film Kapton (registered trademark) manufactured by Toray-Dupont Co., Ltd. was used as the waste material containing polyimide. Potassium hydroxide (KOH) was used as the basic substance, and 25 parts by mass of potassium hydroxide was dissolved in 40 parts by mass of water. The pH of this aqueous potassium hydroxide solution was 14. Then, 50 parts by mass of the raw material polyimide was mixed and dissolved in 65 parts by mass of the potassium hydroxide aqueous solution to obtain a treatment liquid in which the polyimide was dissolved by alkali hydrolysis. This dissolution was performed at a temperature of 80° C. for 180 minutes.
　次に、上記処理液に酸性物質を添加することにより、処理液を中和すると共に粒子を処理液中に析出させた。ここで、酸性物質としては硫酸を用い、上記水酸化カリウム２５質量部に対して６２．５％濃度の硫酸を４０質量部添加し、６０分間撹拌した。 Next, an acidic substance was added to the treatment liquid to neutralize the treatment liquid and precipitate particles in the treatment liquid. Here, sulfuric acid was used as the acidic substance, and 40 parts by mass of 62.5% strength sulfuric acid was added to 25 parts by mass of the above potassium hydroxide, followed by stirring for 60 minutes.
　次に、ポリアミド酸を含む複数の粒子が析出した処理液を濾過して固形分を分離した。次に、分離した固形分を水洗した。水洗は、濾過した固形分を水に入れて常温で２０分間撹拌する工程を一工程として、この工程を６回繰り返した。次に、水洗した固形分を減圧により脱水して乾燥することによって、含水率３８％のポリアミド酸粉体を得た。 Next, the treatment liquid in which a plurality of particles containing polyamic acid were deposited was filtered to separate the solid content. Next, the separated solid content was washed with water. Washing with water was repeated 6 times, with one step being a step of adding the filtered solid content to water and stirring at room temperature for 20 minutes. Then, the solid content washed with water was dehydrated under reduced pressure and dried to obtain a polyamic acid powder having a water content of 38%.
　得られたポリアミド酸粉体に含まれる複数の粒子の粒径は４．０μｍ以上７．０μｍ以下の範囲であった。また得られたポリアミド酸粉体に含まれるアルカリ金属の含有量は１．０質量％であった。 The particle size of the plurality of particles contained in the obtained polyamic acid powder was in the range of 4.0 μm or more and 7.0 μm or less. The content of alkali metal contained in the obtained polyamic acid powder was 1.0% by mass.
　なお、含水率の測定は、ケツト電子製の水分計「ＲＤＭＸ５０」を使用した。またアルカリ金属の含有量の測定は東亜ディーケーケー株式会社製のアルカリ度計「ＡＬＦ－１６００」を使用した。 Note that the water content was measured using a moisture meter "RDMX50" manufactured by Kett Electronics. The alkali metal content was measured with an alkali meter "ALF-1600" manufactured by Toa DKK Co., Ltd.
　得られたポリアミド酸粉体の５０質量部と、ジメチルホルムアミドの１００質量部とを４０℃で加温しながら溶解させて溶解させて、ポリアミド酸溶液を得た。 50 parts by mass of the obtained polyamic acid powder and 100 parts by mass of dimethylformamide were dissolved while heating at 40° C. to obtain a polyamic acid solution.
　（実施例２）
　減圧脱水の条件を変更し、含水率３０質量％のポリアミド酸粉体を得た以外は、実施例１と同様にして、ポリアミド酸粉体を得た。また実施例１と同様にして、得られたポリアミド酸粉体の５０質量部と、ジメチルホルムアミドの１００質量部とを４０℃で加温しながら溶解させて溶解させて、ポリアミド酸溶液を得た。 (Example 2)
A polyamic acid powder was obtained in the same manner as in Example 1 except that the conditions of the dehydration under reduced pressure were changed to obtain the polyamic acid powder having a water content of 30 mass %. Further, in the same manner as in Example 1, 50 parts by mass of the obtained polyamic acid powder and 100 parts by mass of dimethylformamide were dissolved while heating at 40° C. to obtain a polyamic acid solution. ..
　（実施例３）
　減圧脱水の条件を変更し、含水率５０質量％のポリアミド酸粉体を得た以外は、実施例１と同様にして、ポリアミド酸粉体を得た。また実施例１と同様にして、得られたポリアミド酸粉体の５０質量部と、ジメチルホルムアミドの１００質量部とを４０℃で加温しながら溶解させて溶解させて、ポリアミド酸溶液を得た。 (Example 3)
A polyamic acid powder was obtained in the same manner as in Example 1 except that the conditions of the dehydration under reduced pressure were changed to obtain the polyamic acid powder having a water content of 50% by mass. Further, in the same manner as in Example 1, 50 parts by mass of the obtained polyamic acid powder and 100 parts by mass of dimethylformamide were dissolved while heating at 40° C. to obtain a polyamic acid solution. ..
　（実施例４）
　減圧脱水の条件を変更し、含水率６０質量％のポリアミド酸粉体を得た以外は、実施例１と同様にして、ポリアミド酸粉体を得た。また実施例１と同様にして、得られたポリアミド酸粉体の５０質量部と、ジメチルホルムアミドの１００質量部とを４０℃で加温しながら溶解させて溶解させて、ポリアミド酸溶液を得た。 (Example 4)
A polyamic acid powder was obtained in the same manner as in Example 1 except that the conditions of dehydration under reduced pressure were changed to obtain a polyamic acid powder having a water content of 60% by mass. Further, in the same manner as in Example 1, 50 parts by mass of the obtained polyamic acid powder and 100 parts by mass of dimethylformamide were dissolved while heating at 40° C. to obtain a polyamic acid solution. ..
　（実施例５）
　塩基性物質として、水酸化カリウムの代わりに、水酸化ナトリウムを用いた以外は、実施例１と同様にして、ポリアミド酸を得た。得られたポリアミド酸粉体に含まれる複数の粒子の粒径は４．０μｍ以上７．０μｍ以下の範囲であった。また得られたポリアミド酸粉体に含まれるアルカリ金属の含有量は１．０質量％であった。 (Example 5)
Polyamic acid was obtained in the same manner as in Example 1 except that sodium hydroxide was used as the basic substance instead of potassium hydroxide. The particle size of the plurality of particles contained in the obtained polyamic acid powder was in the range of 4.0 μm or more and 7.0 μm or less. The content of alkali metal contained in the obtained polyamic acid powder was 1.0% by mass.
　得られたポリアミド酸粉体の５０質量部と、Ｎ－メチル－２－ピロリドンの１００質量部とを４０℃で加温しながら溶解させて溶解させて、ポリアミド酸溶液を得た。 50 parts by mass of the obtained polyamic acid powder and 100 parts by mass of N-methyl-2-pyrrolidone were dissolved by heating at 40° C. to obtain a polyamic acid solution.
　（比較例）
　実施例１のポリアミド酸粉体を１００℃で加熱して、水分を蒸発させることにより、含水率が０．５質量％のポリアミド酸粉体を得た。得られたポリアミド酸粉体の５０質量部と、ジメチルホルムアミドの１００質量部とを４０℃で加温しながら溶解させて溶解させて、ポリアミド酸溶液を得た。 (Comparative example)
The polyamic acid powder of Example 1 was heated at 100° C. to evaporate the water to obtain a polyamic acid powder having a water content of 0.5% by mass. 50 parts by mass of the obtained polyamic acid powder and 100 parts by mass of dimethylformamide were dissolved while heating at 40° C. to obtain a polyamic acid solution.
　（溶解性）
　実施例１～５及び比較例で得られたポリアミド酸溶液について、ポリアミド酸溶液中に溶解しなかったポリアミド酸粉体の有無を目視で確認した。そして、以下の評価をした。結果を表１に示す。
Ａ：溶解しなかったポリアミド酸粉体が見られなかった。
Ｂ：溶解しなかったポリアミド酸粉体がわずかに見られた。
Ｃ：溶解しなかったポリアミド酸粉体が多く見られた。 (Solubility)
Regarding the polyamic acid solutions obtained in Examples 1 to 5 and Comparative Example, the presence or absence of polyamic acid powder which was not dissolved in the polyamic acid solution was visually confirmed. Then, the following evaluations were made. The results are shown in Table 1.
A: Polyamic acid powder that did not dissolve was not seen.
B: Polyamic acid powder that did not dissolve was slightly seen.
C: Many polyamic acid powders that were not dissolved were found.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　（まとめ）
　以上説明したように、第１の態様に係るポリアミド酸粉体は、ポリイミド及び塩基性物質を含有する処理液から析出した複数の粒子を含むポリアミド酸粉体である。前記複数の粒子の少なくとも一部はポリアミド酸を含有する。含水率が３０質量％以上６０質量％以下である。 (Summary)
As described above, the polyamic acid powder according to the first aspect is a polyamic acid powder containing a plurality of particles precipitated from the treatment liquid containing the polyimide and the basic substance. At least a part of the plurality of particles contains a polyamic acid. The water content is 30% by mass or more and 60% by mass or less.
　この態様によれば、乾燥させる際の加熱により各粒子に含有されているポリアミド酸のイミド化が進みにくく、溶剤に溶解しやすい、という利点がある。 According to this aspect, there is an advantage that the polyamic acid contained in each particle is less likely to be imidized by heating during drying and is easily dissolved in a solvent.
　第２の態様に係るポリアミド酸粉体は、第１の態様において、前記処理液は、ポリイミドを含む廃材を溶解させて得られる。 The polyamic acid powder according to the second aspect is obtained by dissolving the waste material containing the polyimide in the treatment liquid in the first aspect.
　この態様によれば、ポリイミドを含む廃材を再生して有効活用することができる、という利点がある。 According to this aspect, there is an advantage that a waste material containing polyimide can be recycled and effectively utilized.
　第３の態様に係るポリアミド酸粉体は、第１又は２の態様において、前記各粒子の粒径が１０μｍ以下である。 In the polyamic acid powder according to the third aspect, in the first or second aspect, each particle has a particle size of 10 μm or less.
　この態様によれば、各粒子の表面積を比較的大きくすることができ、溶剤に溶解しやすい、という利点がある。 According to this aspect, there is an advantage that the surface area of each particle can be made relatively large and it is easily dissolved in a solvent.
　第４の態様に係るポリアミド酸粉体は、第１～３のいずれか一つの態様において、前記塩基性物質に由来するアルカリ金属の含有量が１．０質量％以下である。 In the polyamic acid powder according to the fourth aspect, in any one of the first to third aspects, the content of the alkali metal derived from the basic substance is 1.0% by mass or less.
　この態様によれば、ポリアミド酸粉体中のポリアミド酸を分解するアルカリ金属の含有量を少なくすることができ、保存安定性に優れる、という利点がある。 According to this aspect, it is possible to reduce the content of the alkali metal that decomposes the polyamic acid in the polyamic acid powder, and there is an advantage that the storage stability is excellent.
　第５の態様に係るポリアミド酸溶液の製造方法は、第１～４のいずれか一つの態様におけるポリアミド酸粉体を溶剤に溶解させた。 In the method for producing a polyamic acid solution according to the fifth aspect, the polyamic acid powder according to any one of the first to fourth aspects is dissolved in a solvent.
　この態様によれば、ポリアミド酸溶液中にポリアミド酸粉体の溶け残りを少なくすることができ、均質なポリアミド酸溶液が得やすくなる、という利点がある。 According to this aspect, it is possible to reduce the undissolved polyamic acid powder in the polyamic acid solution, and it is easy to obtain a homogeneous polyamic acid solution.
　第６の態様に係るポリアミド酸粉体の製造方法は、ポリイミドを含む廃材及び塩基性物質が溶解した処理液と酸性物質とを混合することにより、ポリアミド酸を含有する粒子を析出させる。含水率が３０質量％以上６０質量％以下となるまで前記粒子を乾燥させる。 In the method for producing a polyamic acid powder according to the sixth aspect, particles containing polyamic acid are precipitated by mixing a treatment liquid in which waste material containing polyimide and a basic substance are dissolved with an acidic substance. The particles are dried until the water content is 30% by mass or more and 60% by mass or less.
　この態様によれば、乾燥させる際の加熱により各粒子に含有されているポリアミド酸のイミド化が進みにくく、溶剤に溶解しやすい、という利点がある。 According to this aspect, there is an advantage that the polyamic acid contained in each particle is less likely to be imidized by heating during drying and is easily dissolved in a solvent.

Claims (6)

  1. 　ポリイミド及び塩基性物質を含有する処理液から析出した複数の粒子を含むポリアミド酸粉体であって、
    　前記複数の粒子の少なくとも一部はポリアミド酸を含有し、
    　含水率が３０質量％以上６０質量％以下である、
    　ポリアミド酸粉体。     A polyamic acid powder containing a plurality of particles precipitated from a treatment liquid containing a polyimide and a basic substance,
    At least a part of the plurality of particles contains a polyamic acid,
    The water content is 30% by mass or more and 60% by mass or less,
    Polyamic acid powder.
  2. 　前記処理液は、ポリイミドを含む廃材を溶解させて得られる、
    　請求項１に記載のポリアミド酸粉体。     The treatment liquid is obtained by dissolving a waste material containing polyimide.
    The polyamic acid powder according to claim 1.
  3. 　前記各粒子の粒径が１０μｍ以下である、
    　請求項１又は２に記載のポリアミド酸粉体。     The particle size of each particle is 10 μm or less,
    The polyamic acid powder according to claim 1 or 2.
  4. 　前記塩基性物質に由来するアルカリ金属の含有量が１．０質量％以下である、
    　請求項１～３のいずれか一項に記載のポリアミド酸粉体。     The content of the alkali metal derived from the basic substance is 1.0% by mass or less,
    The polyamic acid powder according to any one of claims 1 to 3.
  5. 　請求項１～４のいずれか一項に記載のポリアミド酸粉体を溶剤に溶解させた、
    　ポリアミド酸溶液の製造方法。     The polyamic acid powder according to any one of claims 1 to 4 is dissolved in a solvent,
    Method for producing polyamic acid solution.
  6. 　ポリイミドを含む廃材及び塩基性物質が溶解している処理液と、酸性物質とを混合することにより、ポリアミド酸を含有する粒子を析出させ、
    　含水率が３０質量％以上６０質量％以下となるまで前記粒子を乾燥させる、
    　ポリアミド酸粉体の製造方法。     By mixing a treatment liquid in which a waste material containing a polyimide and a basic substance are dissolved, and an acidic substance, particles containing a polyamic acid are precipitated,
    Drying the particles until the water content is 30% by mass or more and 60% by mass or less,
    Method for producing polyamic acid powder.
PCT/JP2019/007917 2019-02-28 2019-02-28 Polyamide acid powder, method of manufacturing polyamide acid powder, and method of manufacturing polyamide acid solution WO2020174679A1 (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS642283B2 (en) * 1982-02-12 1989-01-17 Nippon Electric Co
JP2006124530A (en) * 2004-10-29 2006-05-18 Toray Ind Inc Method for alkaline hydrolysis of polyimide and method for recovering low molecular weight compound
JP2014015602A (en) * 2012-06-12 2014-01-30 Nakata Coating Co Ltd Imido group-containing compound and solution of imido group-containing compound
JP5695675B2 (en) * 2011-01-14 2015-04-08 田中　正美 Polyimide powder, polyimide solution and method for producing polyimide powder
JP2017165990A (en) * 2017-06-30 2017-09-21 株式会社仲田コーティング Manufacturing method of imide group-containing compound aqueous solvent solution

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS642283B2 (en) * 1982-02-12 1989-01-17 Nippon Electric Co
JP2006124530A (en) * 2004-10-29 2006-05-18 Toray Ind Inc Method for alkaline hydrolysis of polyimide and method for recovering low molecular weight compound
JP5695675B2 (en) * 2011-01-14 2015-04-08 田中　正美 Polyimide powder, polyimide solution and method for producing polyimide powder
JP2014015602A (en) * 2012-06-12 2014-01-30 Nakata Coating Co Ltd Imido group-containing compound and solution of imido group-containing compound
JP2017165990A (en) * 2017-06-30 2017-09-21 株式会社仲田コーティング Manufacturing method of imide group-containing compound aqueous solvent solution

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