WO2023032569A1 - 繊維強化複合材料の製造方法 - Google Patents
繊維強化複合材料の製造方法 Download PDFInfo
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- WO2023032569A1 WO2023032569A1 PCT/JP2022/029732 JP2022029732W WO2023032569A1 WO 2023032569 A1 WO2023032569 A1 WO 2023032569A1 JP 2022029732 W JP2022029732 W JP 2022029732W WO 2023032569 A1 WO2023032569 A1 WO 2023032569A1
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- fiber
- resin
- reinforced composite
- composite material
- molecular weight
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- 239000000463 material Substances 0.000 title claims abstract description 99
- 239000003733 fiber-reinforced composite Substances 0.000 title claims abstract description 94
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 27
- 239000011347 resin Substances 0.000 claims abstract description 137
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- 238000004898 kneading Methods 0.000 claims abstract description 48
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- 230000002093 peripheral effect Effects 0.000 claims abstract description 18
- 238000001746 injection moulding Methods 0.000 claims description 25
- 239000003365 glass fiber Substances 0.000 claims description 16
- -1 polypropylene Polymers 0.000 claims description 14
- 238000010008 shearing Methods 0.000 claims description 14
- 239000004743 Polypropylene Substances 0.000 claims description 13
- 229920001155 polypropylene Polymers 0.000 claims description 13
- 238000000465 moulding Methods 0.000 claims description 5
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- 229920002492 poly(sulfone) Polymers 0.000 claims description 4
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- 229920000139 polyethylene terephthalate Polymers 0.000 claims description 4
- 239000005020 polyethylene terephthalate Substances 0.000 claims description 4
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- 238000002347 injection Methods 0.000 claims description 3
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- 238000012545 processing Methods 0.000 description 44
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- 235000007164 Oryza sativa Nutrition 0.000 description 1
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- 229920008285 Poly(ether ketone) PEK Polymers 0.000 description 1
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- 239000004952 Polyamide Substances 0.000 description 1
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- 229910052796 boron Inorganic materials 0.000 description 1
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- 238000000691 measurement method Methods 0.000 description 1
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- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 1
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- 150000002978 peroxides Chemical class 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 229920002647 polyamide Polymers 0.000 description 1
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- 229920006259 thermoplastic polyimide Polymers 0.000 description 1
- VZCYOOQTPOCHFL-UHFFFAOYSA-N trans-butenedioic acid Natural products OC(=O)C=CC(O)=O VZCYOOQTPOCHFL-UHFFFAOYSA-N 0.000 description 1
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Images
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B7/00—Mixing; Kneading
- B29B7/80—Component parts, details or accessories; Auxiliary operations
- B29B7/88—Adding charges, i.e. additives
- B29B7/90—Fillers or reinforcements, e.g. fibres
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B7/00—Mixing; Kneading
- B29B7/30—Mixing; Kneading continuous, with mechanical mixing or kneading devices
- B29B7/34—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices
- B29B7/38—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B7/00—Mixing; Kneading
- B29B7/30—Mixing; Kneading continuous, with mechanical mixing or kneading devices
- B29B7/34—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices
- B29B7/38—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary
- B29B7/40—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary with single shaft
- B29B7/42—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary with single shaft with screw or helix
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B7/00—Mixing; Kneading
- B29B7/80—Component parts, details or accessories; Auxiliary operations
- B29B7/84—Venting or degassing ; Removing liquids, e.g. by evaporating components
- B29B7/845—Venting, degassing or removing evaporated components in devices with rotary stirrers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/0005—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor using fibre reinforcements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/25—Component parts, details or accessories; Auxiliary operations
- B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
- B29C48/375—Plasticisers, homogenisers or feeders comprising two or more stages
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/25—Component parts, details or accessories; Auxiliary operations
- B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
- B29C48/50—Details of extruders
- B29C48/505—Screws
- B29C48/51—Screws with internal flow passages, e.g. for molten material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/25—Component parts, details or accessories; Auxiliary operations
- B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
- B29C48/50—Details of extruders
- B29C48/74—Bypassing means, i.e. part of the molten material being diverted into downstream stages of the extruder
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
- B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
- B29C70/06—Fibrous reinforcements only
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
- B29K2105/06—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts
- B29K2105/12—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts of short lengths, e.g. chopped filaments, staple fibres or bristles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2309/00—Use of inorganic materials not provided for in groups B29K2303/00 - B29K2307/00, as reinforcement
- B29K2309/08—Glass
Definitions
- the present invention relates to a method for producing a fiber-reinforced composite material suitable as a material for thin molded products such as speaker diaphragms, which are produced by injection molding.
- a fiber-reinforced composite resin (material) to which reinforcing fibers are added to improve mechanical properties is manufactured by dispersing reinforcing fibers in resin.
- resin material to which reinforcing fibers are added to improve mechanical properties
- it is necessary to increase the viscosity to some extent during kneading using a twin-screw kneading extruder. be.
- the viscosity increases by adding reinforcing fibers to the resin, it has been difficult to produce a low-viscosity fiber-reinforced composite material.
- Patent Document 1 in order to stably produce a reinforced polyamide resin composition having excellent molding fluidity and surface appearance as well as strength and rigidity, the resin is melt-kneaded to reduce the melt viscosity of the polyamide resin.
- Patent Document 1 describes a method for producing a polyamide resin composition in which an inorganic filler is blended from a side feed.
- An object of the present invention is to provide a method for producing a low-viscosity fiber-reinforced composite material with high fluidity. Another object of the present invention is to reduce the viscosity of the fiber-reinforced composite material while maintaining the mechanical properties of the molded article improved by the fibers.
- the method for producing a fiber-reinforced composite material of the present invention comprises a fiber dispersion step of kneading a resin and fibers and dispersing the fibers in the resin to form a fiber-dispersed resin.
- the viscosity of the fiber-reinforced composite material can be reduced by carrying out the molecular weight reduction step of reducing the molecular weight of the fiber-dispersed resin. Therefore, it is possible to produce a low-viscosity fiber-reinforced composite material having high fluidity and suitable as a material for injection molding. Further, after dispersing the fibers in the fiber dispersing step, the viscosity of the fiber-dispersed resin is reduced in a short period of time in the molecular weight reduction step, thereby suppressing breakage of the fibers and maintaining the fiber length. Therefore, it is possible to reduce the viscosity of the fiber-reinforced composite material while maintaining the mechanical properties of the molded product of the fiber-reinforced composite material.
- Cross-sectional view of twin-screw kneading extruder A perspective view showing a state in which two screws in a twin-screw kneading extrusion unit are engaged with each other.
- Cross-sectional view of defoamer Cross-sectional view of high shear processing part
- Sectional view of high shear machining showing both barrel and screw in cross section
- Perspective view of cylinder The side view which shows the flow direction of fiber dispersion resin with respect to a screw.
- Cross-sectional view of the high-shear processing part showing the flow direction of the fiber-dispersed resin when the screw rotates
- Graph showing the relationship between the number of rotations of the screw body and the tensile strength of the fiber-reinforced composite material molded product Graph showing the relationship between the number of revolutions of the screw body and the bending strength of the fiber-reinforced composite material molded product
- the method for producing a fiber-reinforced composite material of the present embodiment includes a fiber dispersion step and a molecular weight reduction step.
- the fiber dispersion step is a step of kneading a resin and fibers to disperse the fibers in the resin. It is carried out using a twin-screw kneading extruder or the like. Examples of the twin-screw kneading extruder include twin-screw kneading extruder TEM series (manufactured by Shibaura Machine Co., Ltd.).
- Fibers contained in the raw material include glass fiber (GF), carbon fiber (CF, unused and recycled products), aramid fiber (Kevlar fiber), boron fiber, etc. Even if one type is used, two types The above may be used in combination.
- the fiber-reinforced composite material may contain components other than the resin and reinforcing fibers described above.
- Components that may be contained include, for example, antioxidants (sulfur-based, phosphorus-based), carboxylic anhydrides, maleic acid, plasticizers, UV absorbers, flame retardants, crystal nucleating agents and other additives and various fillers ( carbon black, talc, metal powder, CNT, silica particles, mica), etc., and the blending amount is within a range that allows the fiber-reinforced composite material to maintain strength and elasticity according to the application.
- the weight ratio between the resin and the fibers used in the fiber dispersion process may be appropriately set according to the mechanical properties required for the fiber-reinforced composite material to be manufactured.
- the weight ratio (fiber/resin) is preferably 7/3 or less, and 6/4 or less, from the viewpoint of uniformly dispersing the fibers in the resin in the fiber-reinforced composite material and improving the workability when pulling the strands in pellet production. is more preferred, and 5/5 or less is even more preferred.
- the weight ratio (fiber/resin) is preferably 1/9 or more, more preferably 2/8 or more, and even more preferably 3/7 or more.
- the conditions such as the number of revolutions and temperature can be adjusted according to the types and weight ratios of the resin and fibers, so that the fibers can be uniformly dispersed in the resin. It should be set as appropriate.
- GF polypropylene
- GF/PP weight ratio
- the extrusion rate is 10 to 50 kg/h
- the rotation speed is 100 to
- a twin-screw kneading extruder can be used at 500 rpm, a barrel temperature of 150 to 250° C., and a processing time of about 60 to 180 seconds to obtain a fiber-dispersed resin in which GF is uniformly dispersed in PP.
- the molecular weight reduction step is a step of reducing the molecular weight of a fiber-dispersed resin in which fibers are dispersed to obtain a fiber-reinforced composite material with low viscosity and high fluidity, and is performed using a continuous high shear processing device.
- the viscosity decrease due to temperature increase and shear rate increase is reversible, whereas the viscosity decrease due to resin molecular weight decrease is irreversible. Therefore, by measuring the viscosity and spiral length of the fiber-reinforced composite material under predetermined conditions, it is possible to indirectly evaluate the extent to which the fiber-dispersed resin has been reduced in molecular weight by the molecular weight reduction step.
- the fiber-dispersed resin is conveyed along the outer peripheral surface of a screw body having a passage inside in the high shear processing unit of the continuous high shear processing device, the inlet of the passage on the outer peripheral surface and an outlet, the transportation of the fiber-dispersed resin is restricted by a barrier portion provided between the outlet and the fiber-dispersed resin.
- the rotation speed of the screw body is set to 1000 rpm or more and 3600 rpm or less, and a shearing force is applied to the fiber-dispersed resin, and the fiber-dispersed resin is passed from the entrance of the passage to the exit of the passage.
- lowering the molecular weight of the fiber-dispersed resin means reducing the weight-average molecular weight (Mw) of the resin contained in the fiber-dispersed resin.
- Mw weight-average molecular weight
- the weight average molecular weight is changed from about 250,000 to 1,200,000 after the fiber dispersion step and before the molecular weight reduction step, to 50,000 to 200,000 by the molecular weight reduction step. 000 or so.
- the molecular weight of the fiber-dispersed resin decreases before reaching the critical stress for fiber breakage, fiber breakage can be prevented and the fiber length can be maintained. Therefore, it is possible to suppress deterioration of the function of the fiber-reinforced composite material due to breakage of fibers while imparting fluidity suitable for injection molding to the fiber-reinforced composite material. For this reason, it is possible to produce a fiber-reinforced composite material for injection molding that is suitable for molding of complicated shapes and thin articles, which can form molded articles having good mechanical properties.
- the molecular weight reduction step is performed by reducing the weight average molecular weight of the fiber dispersion resin before the molecular weight reduction step to 100%, and the fiber after the molecular weight reduction step. It is preferable to reduce the molecular weight of the fiber-dispersed resin so that the weight average molecular weight of the resin in the reinforced composite material is 30% or more and 65% or less.
- a shearing force is applied to the fiber-dispersed resin using a high-shearing processing unit in a continuous high-shearing processing device, which will be described later, without adding an additive such as a peroxide that promotes a thermal decomposition reaction.
- a fiber-reinforced composite material having fluidity suitable for injection molding can be obtained.
- a homogeneous fiber-reinforced composite material with a small polydispersity can be produced by reducing the molecular weight of the fiber-dispersed resin by applying a shearing force without using additives to promote the thermal decomposition reaction. can be manufactured.
- the time required for the molecular weight reduction step is preferably short from the viewpoint of suppressing excessive heat deterioration.
- the total time required for the molecular weight reduction step is preferably 30 seconds or less, more preferably 20 seconds or less.
- the time for each divided molecular weight reduction step is preferably 15 seconds or less, more preferably 10 seconds or less. Since thermal deterioration of the fiber-dispersed resin is suppressed by shortening the time of the molecular weight reduction step, the barrel temperature can be set to a high temperature.
- Polypropylene, polysulfone, polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, and polyphenylene sulfide are preferable as resins because they can be reduced in molecular weight in a short period of time.
- these resins whose viscosity is reduced in a short period of time, it is possible to suppress breakage of fibers in the step of reducing the molecular weight. Therefore, it is possible to reduce the viscosity of the fiber-reinforced composite material and manufacture a molded product of the fiber-reinforced composite material having excellent mechanical properties.
- a fiber-reinforced composite material with high fluidity and low viscosity can be obtained.
- the spiral length (spiral flow length) is 100 cm or more, 110 cm or more, or 120 cm or more, and the zero shear viscosity at a temperature of 200 ° C. is 1600 Pa s or less, 1200 Pa s or less, or 500 Pa s or less.
- Composite materials can be produced.
- the spiral length and viscosity refer to values measured by the evaluation method described in Examples below.
- the fiber-reinforced composite material produced by the production method of the present embodiment has low viscosity and excellent fluidity, so it is suitable as a material for injection molding.
- breakage of the fibers dispersed in the resin in the fiber dispersing process does not proceed excessively. Therefore, the effect of adding fibers to the resin is maintained, and a molded article having excellent mechanical properties can be obtained by injection molding.
- a molded article having a tensile strength of 30 MPa or more, further 40 MPa or more, and a bending strength of 40 MPa or more, further 50 MPa or more can be produced.
- the mechanical properties refer to values evaluated using the evaluation method described in Examples described later.
- the continuous high shear processing device 1 includes a twin-screw kneading extrusion unit 2 as a kneading unit, a high shear processing unit 3 that applies a high shear force to the resin, and a defoaming unit 4. These are connected in series in this order.
- the twin-screw kneading and extruding section 2 is used in a fiber dispersion step of melting and kneading the raw material 10 containing the resin 10a and the fibers 10b and dispersing the fibers in the resin.
- the resin 10a is supplied as pellets
- the fiber 10b is supplied as powder to the twin-screw kneading extruder 2.
- the twin-screw kneading and extruding section 2 includes a barrel 6 and two screws 7 a and 7 b accommodated inside the barrel 6 .
- the barrel 6 has a cylinder portion 8 having a shape obtained by combining two cylinders and a heater for melting the raw material 10 .
- the resin 10a is continuously supplied to the cylinder portion 8 from a supply port 9a provided at one end of the barrel 6, and the fiber 10b is continuously supplied to the cylinder portion 8 from a supply port 9b provided in the middle of the barrel 6.
- FIG. 1 the twin-screw kneading and extruding section 2 includes a barrel 6 and two screws 7 a and 7 b accommodated inside the barrel 6 .
- the barrel 6 has a cylinder portion 8 having a shape obtained by combining two cylinders and a heater for melting the raw material 10 .
- the resin 10a is continuously supplied to the cylinder portion 8 from a supply port 9a provided at one end of the barrel 6, and the
- the screws 7a and 7b each have a feed section 11, a kneading section 12 and a pumping section 13, which are arranged in a row along the axial direction of the screws 7a and 7b.
- the supply port 9b is positioned between the feed section 11 and the kneading section 12, and the fibers 10b are supplied from the supply port 9b by side feeding or the like and dispersed in the resin 9a.
- the feed section 11 has a spirally twisted flight 14 .
- the flights 14 of the screws 7a and 7b rotate while meshing with each other, and direct the raw material 10 including the resin 10a supplied from the supply port 9a and the fibers 10b supplied from the supply port 9b toward the kneading section 12. transport.
- the kneading section 12 has a plurality of discs 15 arranged in the axial direction of the screws 7a and 7b.
- the discs 15 of the screws 7a and 7b rotate while facing each other, and knead the raw material 10 sent from the feed section 11. As shown in FIG.
- the kneaded raw material 10 is fed into the pumping section 13 by the rotation of the screws 7a and 7b.
- the pumping section 13 has a spirally twisted flight 16 .
- the flights 16 of the screws 7 a and 7 b are rotated while meshing with each other, and push out the fiber-dispersed resin from the discharge end of the barrel 6 .
- the resin 10a and the fibers 10b supplied to the supply ports 9a and 9b of the twin-screw kneading and extruding section 2 are melted and kneaded by the heat of the heater. At this time, the fibers 10b are opened and uniformly dispersed in the resin 10a to form a fiber-dispersed resin.
- the fiber-dispersed resin is continuously supplied from the discharge end of the barrel 6 to the high shear processing section 3 as indicated by arrow A in FIG.
- the fiber-dispersed resin is stably supplied from the twin-screw kneading/extrusion section 2 to the high-shear processing section 3 in a predetermined amount with an appropriate viscosity. Therefore, it is possible to reduce the burden on the high-shear processing section 3 that performs the process of reducing the molecular weight following the fiber dispersion process in the twin-screw kneading/extrusion section 2 .
- the purpose of the shearing force applied to the raw material 10 by the twin-screw kneading/extrusion unit 2 is to disperse the fibers 10b in the resin 10a.
- the degree of molecular weight reduction of the resin 10b differs greatly between the twin-screw kneading and extruding section 2 and the high-shear processing section 3. Therefore, only the twin-screw kneading and extruding section 2 is used to obtain fluidity suitable for injection molding. It is difficult to produce a low viscosity fiber reinforced composite with. In order to produce a low-viscosity fiber-reinforced composite material with fluidity suitable for injection molding, it is necessary to reduce the viscosity of the fiber-dispersed resin by a low-molecular-weight process using the high-shear processing part 3.
- the defoaming section 4 shown in FIG. 4 is an element that sucks and removes gas components contained in the fiber-reinforced composite material discharged from the high-shear processing section 3 .
- the defoaming section 4 includes a barrel 22 and a single vent screw 23 housed in the barrel 22.
- - ⁇ Barrel 22 includes a straight cylindrical cylinder portion 24 .
- the sufficiently low-molecular-weight fiber-reinforced composite material extruded from the high-shear processing section 3 is continuously supplied to the cylinder section 24 of the barrel 22 from one end thereof.
- the barrel 22 has a vent port 25.
- the vent port 25 is opened in the intermediate portion of the barrel 22 and connected to the vacuum pump 26 . Furthermore, the other end of the cylinder portion 24 of the barrel 22 is closed with a head portion 27 having a discharge port 28 .
- the vent screw 23 has a helically twisted flight 29, is accommodated in the cylinder part 24, and is rotated in one direction by receiving torque transmitted from a motor (not shown).
- the flight 29 rotates integrally with the vent screw 23 and continuously conveys the kneaded material supplied to the cylinder portion 24 toward the head portion 27 .
- the fiber-reinforced composite material is subjected to the vacuum pressure of the vacuum pump 26 when conveyed to the position corresponding to the vent port 25 . That is, by drawing a negative pressure inside the cylinder portion 24 with a vacuum pump, gaseous substances and other volatile components contained in the fiber-reinforced composite material are continuously sucked and removed from the kneaded material. After gaseous substances and other volatile components are removed, the fiber-reinforced composite material is ejected from the ejection port of the head portion 27 .
- the high-shear processing section 3 is a single-screw extruder that reduces the molecular weight of the fiber-dispersed resin, and includes a barrel 20 and a single screw 21.
- the screw 21 imparts a shearing action to the fiber-dispersed resin supplied from the twin-screw kneading extruder 2 .
- the barrel 20 has a straight cylindrical shape and is arranged horizontally. Barrel 20 is divided into a plurality of barrel elements 31 .
- Each barrel element 31 has a cylindrical through hole 32 .
- the barrel elements 31 are integrally connected by bolting such that the through holes 32 are coaxially continuous.
- the through holes 32 of the barrel element 31 cooperate with each other to define a cylindrical cylinder portion 33 inside the barrel 20 .
- the cylinder portion 33 extends in the axial direction of the barrel 20 .
- a supply port 34 is formed at one end along the axial direction of the barrel 20 .
- the supply port 34 communicates with the cylinder portion 33 , and the fiber-dispersed resin melted by the twin-screw kneading/extrusion portion 2 is continuously supplied to the supply port 34 .
- the barrel 20 has a heater (not shown). The heater adjusts the temperature of barrel 20 as needed.
- the barrel 20 has a coolant passage 35 arranged to surround the cylinder portion 33 . Refrigerant flows along the refrigerant passages 35 and forces the barrel 20 to cool when the temperature of the barrel 20 exceeds a predetermined upper limit. Water, oil, or the like, for example, is used as the coolant.
- the other axial end of the barrel 20 is closed with a head portion 36 .
- the head portion 36 has an ejection port 36a.
- the discharge port 36 a is located on the opposite side of the supply port 34 along the axial direction of the barrel 20 and is connected to the defoaming section 4 .
- the screw 21 has a linear axis along the direction in which the fiber-dispersed resin is conveyed, and has a screw body 37 .
- the screw main body 37 is composed of one rotating shaft 38 and a plurality of cylindrical cylinders 39 .
- the rotating shaft 38 has a first shaft portion 40 and a second shaft portion 41 .
- the first shaft portion 40 is located at the proximal end of the rotating shaft 38 on the one end side of the barrel 20 .
- the first shaft portion 40 includes a joint portion 42 and a stopper portion 43 .
- the joint portion 42 is connected to a drive source such as a motor via a coupling (not shown).
- the stopper portion 43 is provided coaxially with the joint portion 42 .
- the stopper portion 43 has a larger diameter than the joint portion 42 .
- the second shaft portion 41 coaxially extends from the end surface of the stopper portion 43 of the first shaft portion 40 .
- the second shaft portion 41 has a length covering substantially the entire length of the barrel 20 and has a tip facing the head portion 36 .
- a straight axis O ⁇ b>1 coaxially penetrating the first shaft portion 40 and the second shaft portion 41 extends horizontally in the axial direction of the rotation shaft 38 .
- the conveying section 81 and the barrier section 82 may be arranged in a single set or may be arranged in a plurality of sets. In either case, passing through the passage 88 immediately after the molecular weight is reduced can prevent excessive heat deterioration of the fiber-dispersed resin.
- the supply port 34 of the barrel 20 opens toward the conveying portion 81 arranged on the base end side of the screw body 37 .
- the rotating shaft 38 has a first shaft portion 40 and a second shaft portion 41 .
- the first shaft portion 40 is located at the proximal end of the rotating shaft 38 on the one end side of the barrel 20 .
- the first shaft portion 40 includes a joint portion 42 and a stopper portion 43 .
- the joint portion 42 is connected to a drive source such as a motor via a coupling (not shown).
- the stopper portion 43 is provided coaxially with the joint portion 42 .
- the stopper portion 43 has a larger diameter than the joint portion 42 .
- Each transport section 81 has a spirally twisted flight 84 .
- the flight 84 protrudes toward the transport path 53 from the outer circumferential surface of the cylindrical body 39 along the circumferential direction.
- the flight 84 is twisted so as to convey the raw material from the base end of the screw body 37 toward the tip when the screw 21 rotates counterclockwise to the left when viewed from the base end of the screw body 37 . That is, the flight 84 is twisted to the right in the same twisting direction as the flight 84 is right-handed.
- Each barrier section 82 has a spirally twisted flight 86 .
- the flight 86 protrudes toward the transport path 53 from the outer circumferential surface of the cylindrical body 39 along the circumferential direction.
- the flight 86 is twisted so as to convey the fiber-dispersed resin from the distal end of the screw body 37 toward the proximal end when the screw 21 rotates counterclockwise to the left when viewed from the proximal end of the screw body 37 . That is, the flight 86 is twisted to the left in the same twisting direction as the flight 86 and is a reverse screw in the direction opposite to that of the flight 84 .
- the twist pitch of the flight 86 of each barrier part 82 is set equal to or smaller than the twist pitch of the flight 84 of the transport part 81 . Furthermore, a slight clearance is ensured between the tops of the flights 84 and 86 and the inner peripheral surface of the cylinder portion 33 of the barrel 20 .
- the clearance between the outer diameter portion of the barrier portion 82 (the top portions of the flights 84 and 86) and the inner peripheral surface of the cylinder portion 33 is preferably set within a range of 0.1 mm or more and 2 mm or less. More preferably, the clearance is set in the range of 0.1 mm or more and 0.7 mm or less. Thereby, it is possible to restrict the fiber-dispersed resin from being conveyed through the clearance.
- the screw body 37 has a plurality of passages 88 extending in the axial direction of the screw body 37 as screw elements. Assuming that one barrier section 82 and two transport sections 81 sandwiching the barrier section 82 are regarded as one unit, the passage 88 straddles the barrier section 82 of each unit in the cylindrical bodies 39 of both transport sections 81 . formed. In this case, the passages 88 are arranged in a row at predetermined intervals (e.g., equal intervals) on the same straight line along the axial direction of the screw body 37 . The passage 88 is provided in the barrier portion 82 sandwiched between the conveying portions 81 .
- Each cylindrical body 39 is configured so that the second shaft portion 41 coaxially penetrates therethrough.
- the second shaft portion 41 has a solid columnar shape with a diameter smaller than that of the stopper portion 43 .
- a pair of keys 45a and 45b are attached to the outer peripheral surface of the second shaft portion 41.
- the keys 45 a and 45 b extend in the axial direction of the second shaft portion 41 at positions shifted by 180° in the circumferential direction of the second shaft portion 41 .
- a pair of key grooves 49a and 49b are formed on the inner peripheral surface of the cylindrical body 39.
- the key grooves 49a and 49b extend in the axial direction of the cylindrical body 39 at positions shifted by 180° in the circumferential direction of the cylindrical body 39.
- the cylindrical body 39 is inserted onto the second shaft portion 41 from the direction of the tip of the second shaft portion 41 with the key grooves 49a and 49b aligned with the keys 45a and 45b of the second shaft portion 41. .
- a first collar 44 is interposed between the cylindrical body 39 first inserted onto the second shaft portion 41 and the end surface of the stopper portion 43 of the first shaft portion 40 .
- a fixing screw 52 is screwed into the tip end surface of the second shaft portion 41 via a second collar 51 (see FIG. 5). , see FIG. 6). By this screwing, all the cylinders 39 are tightened in the axial direction of the second shaft portion 41 between the first collar 44 and the second collar 51, and the end faces of the adjacent cylinders 39 are in close contact without gaps. do.
- the passage 88 is provided inside the cylindrical body 39 at a position eccentric from the axis O1 of the rotating shaft 38 .
- the passageway 88 is off the axis O1 and revolves around the axis O1 when the screw body 37 rotates.
- the passage 88 is, for example, a hole having a circular cross-sectional shape.
- the passage 88 is configured as a hollow space that allows only the flow of the fiber-dispersed resin.
- a wall surface 89 of the passage 88 revolves around the axis O1 without rotating about the axis O1 when the screw body 37 rotates.
- the diameter of the circle may be, for example, about 1 to 5 mm.
- the distance of the passage 88 (length L2, see FIG. 9) may be, for example, about 15 to 90 mm.
- the cross-sectional circle diameter of the passage 88 is preferably 1 to 3 mm, and the distance of the passage 88 is preferably 40 to 60 mm.
- the screw body 37 has, as screw elements, a plurality of conveying portions 81 for conveying the fiber-dispersed resin and a plurality of barrier portions 82 for restricting the flow of the fiber-dispersed resin. are doing. That is, a plurality of conveying portions 81 are arranged at the base end of the screw body 37 corresponding to one end of the barrel 20, and a plurality of conveying portions 81 are arranged at the tip of the screw body 37 corresponding to the other end of the barrel 20. there is Furthermore, between these conveying portions 81 , conveying portions 81 and barrier portions 82 are alternately arranged in the axial direction from the base end to the tip end of the screw body 37 . The number of transporting units 81 and barrier units 82 arranged as a set determines the number of times the high-shear processing unit 3 performs the low-molecular-weight process.
- the fiber-dispersed resin supplied to the high-shear processing section 3 is introduced into the outer peripheral surface of the conveying section 81 located on the base end side of the screw main body 37 .
- the flight 84 of the transport section 81 moves the fiber-dispersed resin toward the screw body 37 as indicated by the solid-line arrow in FIG. Convey continuously toward the tip of the
- the conveying portions 81 and the barrier portions 82 are alternately arranged in the axial direction of the screw body 37, and the passages 88 are provided at intervals in the axial direction of the screw body 37. Therefore, the fiber-dispersed resin introduced into the screw main body 37 from the supply port 34 is reduced in molecular weight as it is transported from the base end to the tip end of the screw main body 37 while being intermittently subjected to repeated shearing action.
- each passage 88 has an inlet 91, an outlet 92, and a passage body 93.
- the inlet 91 and the outlet 92 communicate with each other through a passage body 93 and are provided close to both sides of one barrier section 82 .
- the inlet 91 is opened in the outer peripheral surface near the downstream end of the conveying portion 81, and the outlet 92 is opened. is opened on the outer peripheral surface near the upstream end of the conveying portion 81 .
- An inlet 91 and an outlet 92 that are open on the outer peripheral surface of the same conveying portion 81 are not communicated with each other by a passage body 93 .
- the inlet 91 communicates with the outlet 92 of the adjacent downstream conveying section 81 via the barrier section 82
- the outlet 92 communicates with the inlet 91 of the adjacent upstream conveying section 81 via the barrier section 82 .
- a coolant passage (not shown) extending coaxially along the axis O1 of the rotating shaft 38 may be formed inside the rotating shaft 38 in order to enhance the cooling effect when passing through the passage 88 .
- the coolant passage is formed, one end thereof is connected to an outlet pipe, and the other end can be liquid-tightly closed with the tip of the rotary shaft 38 .
- the refrigerant introduction pipe may be coaxially inserted inside the refrigerant passage. As a result, the coolant circulates along the axial direction of the rotary shaft 38, so that the cooling efficiency when the coolant passes through the passage 88 is improved.
- the filling rate of the fiber-dispersed resin at the portion of the conveying portion 81 corresponding to the conveying portion 81 of the screw body 37 is represented by gradation (shading). That is, in the conveying section 81, the filling rate increases as the color tone darkens. In the conveying section 81 , the filling rate increases as the barrier section 82 is approached, and the filling rate reaches 100% immediately before the barrier section 82 . Thus, in the vicinity of the resin reservoir R, a high shearing force is applied to the fiber-dispersed resin whose filling rate is approximately 100% by the rotation of the screw 21 . Thereby, the fiber-dispersed resin can be made to have a low molecular weight.
- a filling length which is a length in which the fiber-dispersed resin is filled along the conveying direction, is defined by the positional relationship between the passage 88 and the barrier section 82 .
- the length L2 of the passage 88 shown in FIG. 10 must be greater than the length L1 of the barrier portion 82 that the passage 88 straddles. is preferably 2 times or less, more preferably 1.5 times or less, and even more preferably 1.3 times or less of the length L1 of the barrier portion 82 over which the passage 88 spans, from the viewpoint of lowering .
- Conditions for reducing the molecular weight include the number of revolutions of the screw body 37, the inner diameter of the passage 88, the distance, the number of shearing actions, and the like.
- the number of times (the number of resin pools R) to limit the transfer is defined by the number of barrier portions 82 provided with passages 88 between the screw bodies 37 in the high shear processing portion 3 .
- the screw 21 rotates by receiving torque from the drive source.
- the number of rotations of the screw 21 suitable for reducing the molecular weight varies depending on the outer diameter of the screw 21 . In general, the smaller the outer diameter of the screw 21, the higher the preferred rotational speed.
- the number of rotations of the screw 21 is set to 1000 rpm or more and 3600 rpm or less.
- a low-viscosity, fiber-reinforced composite material is obtained that yields high molded articles.
- the rotation speed of the screw 21 is preferably 1000 rpm or more and 3000 rpm or less, more preferably 1500 rpm or more and 3000 rpm or less.
- the shear rate of the screw 21 is preferably 850 (/sec) or more and 2500 (/sec) or less, more preferably 1250 (/sec) or more and 2500 (/sec) or less.
- a configuration in which a plurality of passages 88 are evenly arranged in parallel inside the screw body 37 is preferable.
- an inlet 91 and an outlet 92 (see FIG. 8) of the passage 88 are also provided equally on the outer peripheral surface of the screw body 37 respectively.
- FIG. 11 shows an example in which four passages 88a, 88b, 88c, 88d are provided in parallel inside the screw body 37.
- the plurality of passages 88 being evenly arranged means that the angles of the lines connecting adjacent passages 88 with the axial line (center point) O1 of the cross section of the screw body 37 are equal.
- the angle of the line connecting O1 and the adjacent passages 88 is 90° when there are four passages 88 and is 180° when there are two passages 88 .
- D1 indicates the outer diameter of the screw body 37. As shown in FIG.
- the fiber-dispersed resin is further reduced in molecular weight by using the high shear processing section 3. It has a low molecular weight process. As a result, it is possible to produce a highly fluid, low-viscosity fiber-reinforced composite material suitable for injection molding while maintaining good mechanical properties (mechanical properties) of the molded article obtained by injection molding.
- the spiral length which is an index of moldability, is 100 cm or more. Viscous fiber reinforced composites can be produced. Also, the viscosity of the fiber-reinforced composite material can be controlled by the number of revolutions of the high-shear processing unit 3 .
- a fiber reinforced composite material was produced using a continuous high shear processing device.
- the raw materials used, the configuration of each part, and the manufacturing conditions are described below.
- Resin F704NP (trade name, made by Prime Polymer, Mw451, 000, polypropylene (PP))
- ⁇ Twin-screw kneading extrusion unit for fiber dispersion process: TEM26SX (manufactured by Shibaura Machine Co., Ltd.)> Configuration: feed section, first kneading section, first pumping section, second kneading section, second pumping section Rotational speed: 250 rpm (rotation/minute) Barrel temperature: 195°C Supply amount (extrusion amount): 20 kg/hour
- a fiber-reinforced composite material was produced by kneading the resin and the fiber according to the ratios and conditions shown in the table below using a twin-screw kneading extruder provided with only the twin-screw kneading extruder 2.
- the temperature of the second pumping section in the twin-screw kneading extruder was set at 300°C to produce fiber-reinforced composite materials.
- Tables 1 and 2 and FIGS. 12 to 14 show the results of measuring the fiber-reinforced composite material produced as described above using the following evaluation methods.
- test piece A molded product (test piece) manufactured by injection molding a fiber-reinforced composite material was obtained by collecting glass fibers in the same manner as the pellets described above, measuring the fiber length distribution, and determining the median value (D50) of the fiber length.
- E (( ⁇ 2- ⁇ 1)/( ⁇ 2- ⁇ 1))/1000 E: elastic modulus (GPa) ⁇ 1: strain 0.05% (0.0005) ⁇ 2: strain 0.25% (0.0025) ⁇ 1: Stress at ⁇ 1 (MPa) ⁇ 2: Stress at ⁇ 2 (MPa)
- the fiber length of the fibers in the fiber-reinforced composite material increased as the number of rotations increased. It is considered that this is because the molecular weight of the polypropylene rapidly decreased due to shear heat generation in the high-shear processing section of the continuous high-shear processing apparatus. That is, it can be presumed that the rapid decrease in the viscosity of the fiber-reinforced composite material in the molecular weight reduction step weakened the shear stress applied to the glass fibers, thereby suppressing breakage of the fibers.
- the viscosity of the fiber-reinforced composite material decreases as the rotation speed of the screw body increases in the viscosity-lowering step. From this result, it can be seen that the viscosity of the fiber-reinforced composite material can be adjusted by the rotation speed of the screw body.
- the shear rate (/second) in the molecular weight reduction step in each example and comparative example can be calculated as [ ⁇ x screw diameter of barrel unit x number of revolutions]/[60 x screw groove depth].
- the shear rate in the step of reducing the molecular weight in Example 1 where the number of revolutions of the screw body is 1000 rpm is 838 (/second).
- the weight average molecular weight of the fiber-reinforced composite material is 392,000 in Comparative Example 3 before the molecular weight reduction process, and 230,000 in Example 1 (1000 rpm) after the molecular weight reduction process. and Example 3 (3000 rpm) was 143,000.
- the weight average molecular weight of the fiber-reinforced composite material of Comparative Example 3 before the molecular weight reduction step is 100%, the fiber-reinforced composite material of Example 1 is reduced to about 59% of the weight average molecular weight of Comparative Example 3.
- the fiber-reinforced composite material of Example 3 had a low molecular weight of about 36% of the weight average molecular weight of Comparative Example 3.
- the weight average molecular weight after the molecular weight reduction process is the weight average molecular weight before the molecular weight reduction process. It is preferable to carry out so that the molecular weight is 30% or more and 65% or less.
- the high shear processing unit is used to perform the low molecular weight process, resulting in high fluidity.
- a low-viscosity fiber-reinforced composite material was obtained.
- the viscosity of the fiber-reinforced composite material could be controlled by the processing conditions such as the number of rotations in the process of reducing the molecular weight by the high-shear processing part.
- the fiber-reinforced composite material produced by the fiber dispersion process and the molecular weight reduction process achieves low viscosity and high fluidity suitable for injection molding, while maintaining high mechanical properties of the injection molded product.
- fiber-reinforced composite materials can be molded into molded articles having excellent mechanical properties by injection molding, they are suitable as materials for forming thin molded articles having a thickness of 0.5 mm or less.
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Abstract
Description
本発明は、高い流動性を備えた低粘度の繊維強化複合材料の製造方法を提供することを目的とする。また、繊維によって向上した成形品の力学的特性を維持しながら、繊維強化複合材料の低粘度化を実現することも目的としている。
また、繊維分散工程により繊維を分散させた後に、低分子量化工程により繊維分散樹脂を短時間で低粘度化することで、繊維の破断を抑えて繊維長を維持できる。したがって、繊維強化複合材料の成形品の力学的特性を維持しながら、繊維強化複合材料を低粘度化することができる。
本実施形態の繊維強化複合材料の製造方法は、繊維分散工程と、低分子量化工程と、を備えている。
(繊維分散工程)
繊維分散工程は、樹脂と繊維とを混練して、樹脂中に繊維を分散させる工程であり、連続式高せん断加工装置(以下、適宜、高せん断加工装置ともいう)の二軸混練押出部や二軸混練押出機などを用いて行う。二軸混練押出機としては、例えば、二軸混練押出機TEMシリーズ(芝浦機械(株)製)等が挙げられる。
低分子量化工程は、繊維が分散した繊維分散樹脂を低分子量化して、粘度が低く流動性が高い繊維強化複合材料とする工程であり、連続式高せん断加工装置を用いて行う。
樹脂の粘度が低下する要因には、温度の上昇、せん断速度の増加、分子量の低下の3つがある。これらのうち、温度の上昇およびせん断速度の増加による粘度低下は可逆的であるのに対し、樹脂の分子量の低下による粘度低下は不可逆的である。このため、所定の条件の下で繊維強化複合材料の粘度やスパイラル長を測定することにより、低分子量化工程により繊維分散樹脂が低分子量化した程度を間接的に評価できる。
本実施形態の低分子量化工程は、スクリュ本体によりせん断力を加えることにより、樹脂溜りの繊維分散樹脂にせん断発熱が生じる。このせん断発熱によって繊維分散樹脂の温度をバレル温度よりも高くして、短時間で繊維分散樹脂を低分子量化することが可能になる。したがって、射出成形に使用できる超低粘度の繊維強化複合材料を製造することができる。
本実施形態の製造方法によれば、流動性が高く、低粘度の繊維強化複合材料が得られる。例えば、スパイラル長(スパイラルフロー長)が100cm以上、110cm以上さらには120cm以上であり、温度200℃におけるゼロせん断粘度が1600Pa・s以下、1200Pa・s以下さらには500Pa・s以下である、繊維強化複合材料を製造することができる。本発明において、スパイラル長および粘度(ゼロせん断粘度)は後述する実施例に記載した評価方法により測定した値をいう。
以下、繊維強化複合材料の製造に用いる連続式高せん断加工装置1について説明する。
図1に示すように、連続式高せん断加工装置1は、混練部である二軸混練押出部2、樹脂に高せん断力を付加する高せん断加工部3および脱泡部4を備えており、これらが、この順に直列に接続されている。
第2の軸部41は、ストッパ部43よりも径が小さいソリッドな円柱状である。
図8に示すように、筒体39の内周面に一対のキー溝49a,49bが形成されている。キー溝49a,49bは、筒体39の周方向に180°ずれた位置で筒体39の軸方向に延びている。
<原料>
樹脂:F704NP(商品名、プライムポリマー製、Mw451、000、ポリプロピレン(PP))
繊維(フィラー):ガラス繊維(GF)
構成:フィード部、第1混練部、第1ポンピング部、第2混練部、第2ポンピング部
回転数:250rpm(回転/分間)
バレル温度:195℃
供給量(押出量):20kg/時間
バレルユニットのスクリュ径(D、外径):48mm
スクリュの溝深さ(フライトの高さ):3mm
バレルユニットのスクリュ有効長(スクリュ有効長さL/スクリュ径D):6.25
通路長(L2、図9参照)45mm、断面円形、直径2mm、通路数4(並行して均等に配置)
回転数:500rpm、800rpm、1000rpm、2000rpm、3000rpm、3500rpm
堰き止め数:1
供給量(押出量):20kg/時間
樹脂および繊維を以下の表に示す比率、条件により、図1に示す連続式高せん断加工装置1の二軸混練押出部2を用いて混練して繊維分散樹脂とした。そして、繊維分散樹脂を以下の表に示す条件により連続式高せん断加工装置1の高せん断加工部3を用いて低分子量化して繊維強化複合材料を製造した。
樹脂および繊維を以下の表に示す比率、条件により、二軸混練押出部2のみを備えた二軸混練押出機を用いて混練して繊維強化複合材料を製造した。比較例4および8では、二軸混練押出機における第2ポンピング部の温度を300℃として繊維強化複合材料を製造した。
上述のようにして製造した繊維強化複合材料について、以下の評価方法を用いて測定した結果を表1、表2および図12~図14に示す。
装置:アントンパール製回転式レオメーターMCR102
測定方法:温度200℃におけるゼロせん断粘度を測定
[スパイラル長(流動性)]
射出成形機を用いて渦巻状金型に射出成形した際に試料樹脂が金型内にて流動した距離(渦巻の長さ)を測定する。射出成形機は芝浦機械EC100Nを用いた。
成形温度:235℃
射出圧力(1次/2次):99MPa/70MPa
スクリュ回転数:100rpm
金型冷却温度:50℃
金型:渦巻状金型(流路断面:半円状/半径2.38mm、最大168cm)
繊維強化複合材料のペレットを500℃の大気雰囲気下で樹脂を飛ばし、ガラス繊維を採取した。得られたガラス繊維を形状・粒子径分布測定装置(マイクロトラックベル社製PartAn SI)に投入して、繊維長分布を測定し繊維長の中央値(D50)を求めた。
繊維強化複合材料を射出成形して製造した成形品(テストピース)を、上述したペレット同様の方法でガラス繊維を採取し、繊維長分布を測定し繊維長の中央値(D50)を求めた。
JIS K 7161に準拠して測定した。
射出成形により、中央幅が10mm、長さが175mm、厚み4mmのダンベル形状の試験片を作製した。試験片の形状はダンベル状1A号形とした。引張試験は、卓上形精密万能試験機(島津製作所(株)製オートグラフAG-50kN型)を用い、クロスヘッド速度を5mm/分とし、試験片の破断まで荷重を負荷した。引張強度について以下の計算式から算出した。
F=P/W×D
F:強度(MPa)
P:破壊荷重(MPa)
W:試験片の幅(mm)
D:試験片の厚さ(mm)
引張試験は、JIS K 7161に準拠して測定した。引張弾性率は、引張強度と同様の方法で作製した試験片を用いて行い、試験で得られた応力-歪の関係から、ε1及びε2の歪み2点間に対応する応力/歪み曲線の傾きから求めた。尚、歪は測定前に校正した伸び計(イプシロン社製)にて計測した。
E=((σ2-σ1)/(ε2-ε1))/1000
E:弾性率(GPa)
ε1:歪み0.1%(0.001)
ε2:歪み0.3%(0.003)
σ1:ε1における応力(MPa)
σ2:ε2における応力(MPa)
JIS K 7171に準拠して測定した。
射出成形により、幅が10mm、長さが80mm、厚み4mmの短冊形状の試験片を作製した。曲げ試験は3点曲げとし、卓上形精密万能試験機(島津製作所(株)製オートグラフAG-50kN型)を用いて試験した。クロスヘッド速度を2mm/分とし、試験片の破断まで荷重を負荷した。曲げ強度について以下の計算式から算出した。
F=3×P×L/2×W×D2
F:強度(MPa)
P:破壊荷重(MPa)
L:支点間距離 64mm
W:試験片の幅(mm)
D:試験片の厚さ(mm)
JIS K 7171に準拠して測定した。
射出成形により、幅が10mm、長さが80mm、厚み4mmの短冊形状の試験片を作製した。曲げ試験は3点曲げとし、卓上形精密万能試験機(島津製作所(株)製オートグラフAG-50kN型)を用いて試験した。クロスヘッド速度を2mm/分とし、試験片の破断まで荷重を負荷した。曲げ弾性率は、試験で得られた応力-歪の関係から、ε1及びε2の歪み2点間に対応する応力/歪み曲線の傾きから求めた。
E=((σ2-σ1)/(ε2-ε1))/1000
E:弾性率(GPa)
ε1:歪み0.05%(0.0005)
ε2:歪み0.25%(0.0025)
σ1:ε1における応力(MPa)
σ2:ε2における応力(MPa)
連続式高せん断加工装置における、二軸混練押出部を用いて樹脂に繊維を分散される繊維分散工程の後に、高せん断加工部を用いて低分子量化工程を行うことにより、高い流動性を備えた低粘度の繊維強化複合材料が得られた。
高せん断加工部による低分子量化工程における回転数などの処理条件により、繊維強化複合材料の粘度を制御することができた。
繊維分散工程および低分子量化工程により製造された繊維強化複合材料は、射出成形に適した低い粘度、高い流動性を実現しつつ、射出成形による成形品の力学的特性が高く維持されていた。
Claims (9)
- 樹脂と繊維とを混練して、前記樹脂中に前記繊維を分散させて繊維分散樹脂とする繊維分散工程と、
前記繊維分散樹脂を低分子量化する低分子量化工程と、を備えていることを特徴とする、
繊維強化複合材料の製造方法。 - 前記低分子量化工程は、内部に通路を備えたスクリュ本体の外周面に沿って前記繊維分散樹脂を搬送する際、前記外周面における前記通路の入口と出口との間に設けられた障壁部により前記繊維分散樹脂の搬送を制限して、前記スクリュ本体により前記繊維分散樹脂にせん断力を加えるとともに、前記繊維分散樹脂を前記通路の前記入口から前記通路の出口へ通過させる、
請求項1に記載の繊維強化複合材料の製造方法。 - 前記低分子量化工程は、内部に通路を備えたスクリュ本体の外周面に沿って前記繊維分散樹脂を搬送する際、前記外周面における前記通路の入口と出口との間に設けられた障壁部により前記繊維分散樹脂の搬送を制限して前記障壁部の直前に前記繊維分散樹脂の充満率が100%である樹脂溜りを形成し、前記スクリュ本体の回転数を1000rpm以上3600rpm以下として前記繊維分散樹脂にせん断力を加えるとともに、前記繊維分散樹脂を前記通路の前記入口から前記通路の出口へ通過させる、
請求項1に記載の繊維強化複合材料の製造方法。 - 前記低分子量化工程は、前記低分子量化工程の前における重量平均分子量の30%以上65%以下となるように、前記繊維分散樹脂を低分子量化する、
請求項1に記載の繊維強化複合材料の製造方法。 - 前記樹脂が、ポリプロピレン、ポリスルホン、ポリエチレンテレフタレート、ポリブチレンテレフタレート、ポリエーテルスルホンおよびポリフェニレンサルファイドからなる群から選ばれた、一または複数である、
請求項1に記載の繊維強化複合材料の製造方法。 - 前記繊維が、ガラス繊維である、
請求項4に記載の繊維強化複合材料の製造方法。 - 前記繊維分散工程における、前記ガラス繊維と前記樹脂との重量比(ガラス繊維/樹脂)が、2/8以上5/5以下である、
請求項5に記載の繊維強化複合材料の製造方法。 - 前記低分子量化工程は、前記繊維分散樹脂の重量平均分子量を小さくして、成形温度235℃、1次射出圧力99MPa、金型冷却温度50℃の条件において、流路断面が半径2.38mmの半円状である渦巻状金型を用いて測定したスパイラル長が100cm以上である繊維強化複合材料とする、
請求項1に記載の繊維強化複合材料の製造方法。 - 繊維強化複合材料が射出成形用の繊維強化複合材料である、
請求項1に記載の繊維強化複合材料の製造方法。
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