Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
  • D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
  • D21H23/22—Addition to the formed paper
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
  • D21B1/00—Fibrous raw materials or their mechanical treatment
  • D21B1/04—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres
  • D21B1/12—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres by wet methods, by the use of steam
  • D21B1/30—Defibrating by other means
  • D21B1/32—Defibrating by other means of waste paper
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H13/00—Pulp or paper, comprising synthetic cellulose or non-cellulose fibres or web-forming material
  • D21H13/10—Organic non-cellulose fibres
  • D21H13/20—Organic non-cellulose fibres from macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H13/26—Polyamides; Polyimides
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
  • D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
  • D21H23/22—Addition to the formed paper
  • D21H23/52—Addition to the formed paper by contacting paper with a device carrying the material
  • D21H23/56—Rolls
• • 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
  • Y02W30/64—Paper recycling

Definitions

• the present invention relates to a method for recycling calendered aramid paper and a heat-resistant electrical insulating sheet material. More particularly, the present invention relates to a method for recycling calendered aramid paper that enables reuse of calendered aramid paper that has been incinerated or disposed of without using chemicals, and a heat-resistant electrical insulating sheet material. Is.
• aramid paper is a synthetic paper made of aromatic polyamide and has been used as an electrical insulating material and aircraft honeycomb base due to its excellent heat resistance, flame resistance, electrical insulation, toughness and flexibility.
• DuPont (USA) Nomex (R) fiber paper comprises mixing poly (metaphenylene isophthalamide) floc and fibrid in water, then It is manufactured by papermaking the mixed slurry and then calendering. This paper is known to still have high strength and toughness and excellent electrical insulation even at high temperatures.
• aramid paper scraps and damaged materials are subjected to high-temperature and high-pressure treatment by calendering, they are not defibrated at all with water alone, and are therefore incinerated or disposed of. Also, after being dissolved in an organic solvent, chemical recycling is carried out again to form paper-making raw materials such as flock, fibrid, and pulp as well as virgin raw materials, but this method requires environmental considerations. There is a tendency to increase the cost. Further, regarding recycling of dried aramid paper or aramid board that has not been subjected to high-temperature and high-pressure treatment by calendering, Patent Documents 1 and 2 describe the treatment method. However, since actual aramid paper is mostly used after being calendered, it is difficult to say that these methods are practical.
• Patent Document 3 uses aramid paper pulp obtained by pulverizing aramid paper, and mixes paper with non-aramid fiber at a ratio of 90/10 to 10/90 to produce a sheet of porous aramid.
• this molded product is considered to have insufficient electrical insulation due to its porosity.
• the present invention has been made based on the knowledge that when a specific aramid paper produced through calendering is pulverized by high-pressure jet treatment, a recyclable papermaking material can be obtained with excellent characteristics. That is, the present invention is characterized in that aramid paper formed from a fibrid, a short fiber or a mixture thereof formed from an aromatic polyamide and manufactured through calendering is crushed by high-pressure jet treatment.
• a method for producing a papermaking raw material is provided.
• the present invention also provides a papermaking raw material produced by the above production method.
• the present invention also provides a heat-resistant electrical insulating sheet material characterized by containing the papermaking raw material.
• aramid means a linear polymer compound (aromatic polyamide) in which 60% or more of amide bonds are directly bonded to an aromatic ring.
• aromatic polyamide examples include polymetaphenylene isophthalamide and copolymers thereof, polyparaphenylene terephthalamide and copolymers thereof, poly (paraphenylene) -copoly (3,4 diphenyl ether) terephthalamide, and the like.
• These aramids are industrially produced by, for example, conventionally known interfacial polymerization methods, solution polymerization methods and the like using isophthalic acid chloride and metaphenylenediamine, and can be obtained as commercial products. Is not to be done.
• polymetaphenylene isophthalamide is preferably used in that it has excellent molding processability, thermal adhesiveness, flame retardancy, heat resistance, and the like.
• aramid fibrids are film-form aramid particles having paper-making properties and are also called aramid pulp (see Japanese Patent Publication No. 35-11851, Japanese Patent Publication No. 37-5732, etc.).
• Aramid fibrids are widely known to be used as a papermaking raw material after being disaggregated and beaten in the same manner as ordinary wood pulp, and can be subjected to so-called beating treatment for the purpose of maintaining quality suitable for papermaking. This beating process can be performed by a paper refiner, a beater, or other papermaking raw material processing equipment that exerts a mechanical cutting action.
• the shape change of the fibrid can be monitored by the freeness test method stipulated in Japanese Industrial Standard P8121.
• the freeness of the aramid fibrid after the beating treatment is preferably in the range of 10 cm 3 to 300 cm 3 (Canadian Freeness).
• the strength of the multi-thermal electrical insulation sheet material formed therefrom may be reduced.
• the utilization efficiency of the mechanical power to be input becomes small, the processing amount per unit time is often reduced, and further, the fibrid is miniaturized. Since it proceeds too much, the so-called binder function is likely to be lowered. Therefore, even when trying to obtain a freeness smaller than 10 cm 3 in this way, no particular advantage is recognized.
• the aramid short fiber is obtained by cutting a fiber made of aramid.
• aramid a fiber made of aramid.
• examples of such a fiber include “Teijin Conex (registered trademark)” by Teijin Limited and “Nomex (registered trademark)” by DuPont.
• the length of the aramid short fibers can be selected from the range of generally 1 mm or more and less than 50 mm, preferably 2 to 10 mm. When the length of the short fiber is smaller than 1 mm, the mechanical properties of the sheet material are deteriorated. On the other hand, when the length is 50 mm or more, “entanglement”, “binding”, etc. are likely to occur in the production of aramid paper by the wet method. Prone to defects.
• the aramid paper is a sheet-like material mainly composed of the aramid fibrid, the aramid short fiber, or a mixture thereof, and generally has a thickness in the range of 20 ⁇ m to 1000 ⁇ m. Further, aramid paper generally has a basis weight in the range of 10 g / m 2 to 1000 g / m 2 .
• Aramid paper is generally produced by a method of mixing the above-mentioned aramid fibrid and aramid short fibers and then forming a sheet.
• the liquid permeation is performed.
• a so-called wet papermaking method using water as a medium is preferably selected.
• the mixing ratio of the aramid fibrid and the aramid short fiber can be arbitrary, but the ratio (mass ratio) of the aramid fibrid / aramid short fiber is preferably 1/9 to 9/1. Preferably, it is 2/8 to 8/2.
• a single or mixed aqueous slurry containing at least aramid fibrids and short aramid fibers is fed to a paper machine and dispersed, and then dewatered, squeezed and dried to be wound up as a sheet.
• the method is common.
• As the paper machine a long paper machine, a circular paper machine, a slanted paper machine, and a combination paper machine combining these are used.
• a composite sheet composed of a plurality of paper layers can be obtained by forming and combining slurry having different blending ratios. Additives such as a dispersibility improver, an antifoaming agent, and a paper strength enhancer are used as necessary during papermaking.
• the aramid paper obtained as described above is known to improve the mechanical strength in addition to the density, crystallinity, heat resistance, dimensional stability, etc. by hot pressing at a high temperature and high pressure between a pair of rolls.
• the hot pressure conditions include, but are not limited to, a temperature range of 100 to 350 ° C. and a linear pressure of 50 to 400 kg / cm when using a metal roll.
• a plurality of aramid papers can be laminated during hot pressing. The above hot pressing can be performed a plurality of times in an arbitrary order.
• the high-pressure spraying process means that the calendered aramid paper is immersed in water, sprayed with high pressure from a nozzle together with water, and collides with a hard body for collision, or high-pressure sprayed.
• colliding each other it refers to a process in which the calendared aramid paper is crushed and brought close to the shape of aramid fibrids and aramid short fibers.
• a high-pressure homogenizer is preferably used as an apparatus capable of such treatment, but is not limited thereto.
• examples of the shape of the collision hard body include a ball shape and a flat plate shape, but are not limited thereto.
• the diameter of the nozzle for high-pressure injection is preferably 0.1 to 0.9 mm, but is not limited to this.
• the calendered aramid paper for high-pressure jetting is preferably preliminarily length-weighted average fiber length not more than three times the nozzle diameter by a pulverizer or the like, more preferably not more than twice, most preferably 1. It is good to grind to a size of 5 times or less. When it is 1.5 times or less, nozzle clogging of the calendared aramid paper can be effectively suppressed.
• a method of pulverizing the calendared aramid paper a method of pulverizing and finely pulverizing by a dry method, a wet method or both means is preferable.
• the dry method is a method of using a shredder, a crusher, a kneader or the like, and impacting aramid paper without substantially interposing moisture to decompose it into fine particles.
• the wet method is a method of reducing the particle size by applying an impact to aramid paper in an aqueous medium. Examples of equipment for efficiently carrying out such wet pulverization include a high-speed disintegrator, a refiner, and a beater, but are not limited thereto.
• the injection pressure is preferably in the range of 70 to 300 MPa.
• the injection speed is preferably in the range of 300 to 900 m / s.
• the concentration of the calendared aramid paper when immersed in water is preferably 0.1 to 10 wt%.
• additives such as a dispersibility improver and an antifoaming agent can be used as necessary.
• the high-pressure spraying process can be repeated multiple times as necessary, but if the number of times is excessively large, the cost becomes high, and further, the cutting of the aramid short fiber part advances, and the shape of the short fiber as a papermaking raw material is increased. It is not preferable because it does not stop. In that sense, the retention rate of the length-weighted average fiber length of the calendered aramid paper before and after the high-pressure jet treatment is preferably 80% or more.
• the volume average particle size distribution is a distribution obtained by measuring the particle distribution on a volume basis. Further, the volume average particle diameter is a particle diameter measured on a volume basis.
• the particle size peak is a peak of the volume average particle size distribution. Since the papermaking raw material of the present invention has a three-dimensional shape such as a fiber shape, a particle shape, or an indefinite shape, the size and shape of the papermaking raw material were specified using the particle size peak.
• the particle size peak in the range of 10 ⁇ m or more and less than 100 ⁇ m is considered to mainly represent the relative amount of the separated aramid short fibers, and the above particle size peak is generated after the high pressure injection treatment. It is considered that aramid short fibers are generated. Therefore, in the present invention, it is preferable to perform the high-pressure injection treatment so as to generate a particle size peak in the range of 10 ⁇ m or more and less than 100 ⁇ m in the volume average particle size distribution of the aramid paper after the high-pressure injection treatment, and entanglement as short fibers occurs. It is easy to improve the strength of the heat-resistant electrical insulating sheet material.
• the aramid paper is pulverized before the high pressure injection treatment, and the volume average particle size distribution of the aramid paper before the high pressure injection treatment has a particle size peak in the range of 10 ⁇ m or more and less than 100 ⁇ m and in the range of 100 ⁇ m or more and less than 1000 ⁇ m. It is preferable to perform the high pressure injection process so that the frequency at each particle size peak after the treatment increases in a range of 10 ⁇ m or more and less than 100 ⁇ m and decreases in a range of 100 ⁇ m or more and less than 1000 ⁇ m.
• the particle size peak in the range of 10 um or more and less than 100 um mainly represents the relative amount of the separated aramid short fibers, and the particle size peak in the range of 100 um or more and less than 1000 um.
• the decrease in frequency is considered to indicate that the amount of short aramid fibers is relatively increased, and the amount of unmixed aramid short fibers and aramid fibrids is relatively decreased.
• the entanglement as a short fiber is easy to generate
• the heat-resistant electrical insulating sheet material of the present invention is a sheet-like material containing the papermaking raw material, and generally has a thickness in the range of 20 ⁇ m to 5 mm. Furthermore, the heat-resistant electrical insulating sheet material generally has a basis weight in the range of 10 g / m 2 to 5000 g / m 2 , preferably 10 g / m 2 to 200 g / m 2 .
• the content of the papermaking raw material in the heat-resistant electrical insulation sheet material is not particularly limited as long as the desired electrical insulation is achieved.
• the amount is preferably from 80 to 80% by weight, more preferably from 15 to 80% by weight for obtaining sufficient electrical insulation, and particularly preferably from 30 to 80% by weight for developing sufficient strength.
• the remaining portion may be a new aramid fibrid or a combination of this and an aramid short fiber, but is not limited thereto.
• the heat-resistant electrical insulating sheet material is generally produced by a method of forming a sheet after mixing the aforementioned papermaking raw material and aramid fibrid.
• a method of forming a sheet using an air flow after the papermaking raw material and the aramid fibrid are dispersed and mixed in a liquid medium
• a liquid permeable support for example, a method of discharging a sheet onto a net or a belt to form a sheet and drying it by removing the liquid can be applied.
• a so-called wet papermaking method using water as a medium is preferably selected. Is done.
• a single or mixed aqueous slurry containing aramid fibrid is fed to a papermaking machine and dispersed, followed by dehydration, squeezing and drying operations to form a sheet.
• a winding method is common.
• the paper machine a long paper machine, a circular paper machine, a slanted paper machine, and a combination paper machine combining these are used.
• a composite sheet composed of a plurality of paper layers can be obtained by forming and combining slurry having different blending ratios.
• Additives such as a dispersibility improver, an antifoaming agent, and a paper strength enhancer are used as necessary during papermaking.
• other fibrous components for example, aramid fiber, polyphenylene sulfide fiber, polyether ether ketone fiber, cellulose fiber, PVA fiber, polyester fiber, arylate fiber, liquid crystal polyester fiber, polyethylene naphthalate fiber, etc.
• Glass fiber, rock wool, asbestos, boron fiber and other inorganic fiber glass fibers can be added.
• the heat-resistant electrical insulating sheet material of the present invention since aramid fibrid has excellent properties as a binder, it can efficiently supplement fine particles and other additive components, and the heat-resistant electrical insulating sheet material of the present invention can be produced. In this case, the yield of the raw material is improved, and at the same time, it is possible to overlap the layers in the sheet and reduce the number of through-holes, improving the electrical insulation.
• the heat-resistant electrical insulating sheet material thus obtained can be improved in density and mechanical strength by hot pressing at a high temperature and high pressure between a pair of flat plates or between metal rolls. Examples of conditions for the hot pressure include, but are not limited to, a temperature of 100 to 350 ° C.
• Measurement of particle size distribution The particle size distribution was measured by a light scattering type particle size distribution measuring device (Horiba, Ltd., laser diffraction / scattering type particle size distribution device LA-910).
• Length-weighted average fiber length Using a Fiber Quality Analyzer manufactured by Op Test Equipment, the length-weighted average fiber length of about 4000 fine particles was measured.
• Measurement of basis weight and thickness It was carried out according to JIS C2300-2. Regarding the thickness unevenness, 40 consecutive thicknesses were measured, and the standard deviation was defined as the thickness unevenness.
• a polymetaphenylene isophthalamide fibrid was produced using a pulp particle production apparatus (wet precipitation machine) composed of a combination of a stator and a rotor described in JP-A-52-15621. This was treated with a disaggregator and a beater to adjust the length weighted average fiber length to 0.9 mm (freeness of aramid fibrid: 100 ml (Canadian Freeness)). Meanwhile, a DuPont meta-aramid fiber (Nomex (registered trademark), single yarn fineness 2 denier) was cut into a length of 6 mm (hereinafter referred to as “aramid short fiber”).
• ⁇ 1 aramid paper length-weighted average fiber length, about 80% of the nozzle diameter
• 8 parts by mass of the above ⁇ 1 aramid paper was mixed at a ratio of 92 parts by mass of water, and high-pressure jetting was performed with a high-pressure homogenizer (Starburst 100 HJP-258080 manufactured by Sugino Machine Co., Ltd .: nozzle diameter 0.5 mm) under the conditions shown in Table 1. Then, it was crushed by colliding with a collision hard body (ceramic) to obtain a papermaking raw material.
• ⁇ 1 aramid paper length-weighted average fiber length, about 80% of the nozzle diameter
• Examples 1 to 3, control example Manufacture of heat-resistant electrical insulation sheet material
• the prepared ⁇ 1 aramid paper, the prepared papermaking raw material, and the prepared aramid fibrid were dispersed in each water to prepare a slurry. These slurries were mixed so as to have a blending ratio (mass ratio) shown in Table 1, and a sheet-like material was produced with a tappy hand machine (cross-sectional area of 625 cm 2 ). Subsequently, this was hot-pressed with a metal calender roll at a temperature of 330 ° C. and a linear pressure of 300 kg / cm to obtain a heat-resistant electrical insulating sheet material.
• Table 1 shows the main characteristic values of the heat-resistant electrical insulating sheet material thus obtained.
• the heat-resistant electrical insulating sheet materials of the present invention (Examples 1 to 3) have a length-weighted average fiber length that is maintained as compared with that before the high-pressure injection treatment (control example). Since the cutting of the fiber component has not progressed so much, the strength is high, the thickness unevenness is small, and the appearance is not changed even after treatment at 250 ° C. for 10 minutes, so that it is useful as a heat-resistant electrical insulating sheet material I understand.
• the increase in the components corresponding to 0.3 to 0.4 mm length of aramid short fibers corresponding to each particle size peak 1 resulted in a decrease in air permeability and micro unevenness on the surface.
• the adhesive area when bonded to a sheet, resin or the like is widened, and it is particularly useful as a heat-resistant electrical insulating sheet material for lamination to be bonded to an insulating film or insulating resin.

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• 2013
  • 2013-01-09 JP JP2013001706A patent/JP6065315B2/ja active Active
  • 2013-12-19 KR KR1020157008833A patent/KR102110215B1/ko not_active Expired - Fee Related
  • 2013-12-19 CN CN201380057305.XA patent/CN104736765B/zh not_active Expired - Fee Related
  • 2013-12-19 WO PCT/JP2013/084114 patent/WO2014109203A1/ja not_active Ceased
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