JP2016180022A - Presheet for making fiber-reinforced thermoplastic plastic and production method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a presheet for making fiber-reinforced thermoplastic plastic that has excellent moldability and an excellent surface feeling.SOLUTION: A presheet for making fiber-reinforced thermoplastic plastic is a sheet formed by heating a laminate comprising a web layer comprising reinforced fibers and thermoplastic resin, and a resin layer comprising a thermoplastic resin and having a permeability of more than 0 cm/cms, the resin layer on at least one surface of the presheet for making fiber-reinforced thermoplastic plastic.SELECTED DRAWING: None

Description

  The present invention relates to a pre-sheet for producing a fiber-reinforced thermoplastic for producing a fiber-reinforced thermoplastic and a method for producing the same.

  Fiber reinforced materials composed of glass fibers, carbon fibers, aramid fibers, and other reinforcing fibers, and matrix resins are used in electrical / electronic equipment, office automation equipment, electrical equipment casings, sports / leisure products, aircraft bodies, and automobiles. Used for car bodies and building materials.

  Thermosetting resins and thermoplastic resins are known as matrix resins for fiber reinforced materials. Since it can respond to various shapes, in recent years, the use of fiber reinforced thermoplastic plastics, which are fiber reinforced materials using thermoplastic resins as matrix resins, has been expanding.

  As a method for producing a fiber reinforced thermoplastic, a fiber reinforced thermoplastic plastic-made pre-sheet (hereinafter also simply referred to as “pre-sheet”) including reinforced fibers and a thermoplastic resin is manufactured in advance, and a single sheet or a laminate of the pre-sheet is manufactured. A method of forming is known.

  Patent Document 1 describes a method for producing a pre-sheet for the purpose of strengthening strength by laminating a structure containing reinforcing fibers and a thermoplastic resin and a sheet-like material such as a thermoplastic resin film or a nonwoven fabric and integrating them. Disclosure.

  Patent Document 2 discloses a method for producing a pre-sheet, in which a thermoplastic resin film is laminated on a structure containing reinforcing fibers, and the structure is impregnated with a thermoplastic resin by heating and pressurizing to form a composite.

JP 2012-255065 A JP 2011-21303 A

  As the use of fiber reinforced thermoplastics expands, for example, we produce fiber reinforced thermoplastics that have good moldability to withstand deformation during molding, such as deep drawing, and have an excellent appearance (surface feel). There is a need for a possible pre-sheet for making fiber reinforced thermoplastics. However, Patent Document 1 and Patent Document 2 do not have a detailed description of the characteristics of the pre-sheet relating to these performances.

  An object of the present invention is to provide a pre-sheet for producing a fiber-reinforced thermoplastic plastic that can produce a fiber-reinforced thermoplastic having excellent moldability and excellent surface feel, and a method for producing the same.

The present invention for solving the above-described problems has the following aspects.
[1] A web layer containing a reinforced fiber and a thermoplastic resin, and a resin layer made of a thermoplastic resin and having an air permeability exceeding 0 cm ³ / cm ² · s, wherein at least a pre-sheet for producing a fiber reinforced thermoplastic plastic A pre-sheet for producing a fiber-reinforced thermoplastic, which is a sheet formed by heat-treating a laminate including a resin layer located on one surface.
[2] The pre-sheet for producing a fiber-reinforced thermoplastic plastic according to [1], wherein the web layer further includes a heat-fusible resin.
[3] The pre-sheet for producing a fiber-reinforced thermoplastic plastic according to [1] or [2], wherein the resin layer is a nonwoven fabric.
[4] The fiber-reinforced thermoplastic prefabricated sheet according to any one of [1] to [3], wherein the web layer is an airlaid web formed by an airlaid method.
[5] The fiber-reinforced thermoplastic plastic pre-sheet according to [4], wherein the resin layer is a carrier sheet used for conveying the air-laid web in the air-laid method.
[6] The pre-sheet for producing a fiber-reinforced thermoplastic according to any one of [1] to [5], comprising a plurality of the web layers.
[7] A fiber-reinforced thermoplastic molded article obtained by molding and processing a single sheet or a laminate of the reinforced thermoplastic plastic-producing pre-sheet according to any one of [1] to [6].
[8] A defibrating step of defibrated chopped fiber by defibrating chopped fiber obtained by cutting fiber bundles made of reinforcing fibers by air flow and / or mechanical share, and the defibrated chopped fiber and thermoplastic resin Mixing step for obtaining a web raw material by mixing the resin and the heat-fusible resin, a web forming step for obtaining a web from the web raw material, and a sheet shape made of a thermoplastic resin and having an air permeability exceeding 0 cm ³ / cm ² · s A binding step of heat-treating the web on an object, and binding the defibrated chopped fiber and the thermoplastic resin with the heat-fusible resin;
A process for producing a pre-sheet for producing a fiber-reinforced thermoplastic.
[9] The manufacturing method according to [8], wherein the web forming step includes disposing the web on the sheet-like material.

  The pre-sheet for producing a fiber-reinforced thermoplastic plastic according to the present invention has good moldability that can withstand deformation caused by molding. Moreover, the fiber reinforced thermoplastic plastic obtained from the pre-sheet for producing the fiber reinforced thermoplastic plastic of the present invention has an excellent surface feeling.

It is a table | surface which shows the structure and measurement / evaluation result of the reinforced fiber thermoplastics which concern on an Example and a comparative example. It is a schematic diagram which shows the web formation apparatus which can be used in the manufacturing method of the pre-sheet for fiber-reinforced thermoplastics preparation of this invention.

<Pre-sheet for fiber-reinforced thermoplastic production>
The pre-sheet for producing a fiber-reinforced thermoplastic plastic according to the present invention is a web layer containing reinforcing fibers and a thermoplastic resin, and a resin layer made of a thermoplastic resin and having a permeability of 0 cm ³ / cm ² · s. And a resin layer positioned on at least one surface of the laminate.

  The web layer is a sheet-like material containing reinforcing fibers and a thermoplastic resin. The web layer can be a non-woven fabric, and can be formed by, for example, an airlaid method, a wet papermaking method, a spunlace method, a needle punch method, or the like.

  The web layer may further contain a heat-fusible resin. For example, when the web layer is formed by the airlaid method without using any water, that is, when the web layer is produced by the so-called TDS method (Totally Dry System), the web layer is bonded with the components by heat. For thermal bonding, a heat-fusible resin is included as an essential component. In the TDS method, since no water is used, the web layer can be formed without impairing the functions of the constituent components.

The resin layer may be a sheet-like material made of a thermoplastic resin and having an air permeability exceeding 0 cm ³ / cm ² · s. For example, the resin layer can be a non-woven fabric, and can be formed by, for example, an airlaid method, a spunlace method, a needle punch method, or the like. The resin layer may be in the form of a woven fabric or a film having a large number of uniformly dispersed micropores.

  The heat treatment promotes the interlayer adhesion of each layer in the laminate and the binding between the constituent components in the layer.

(Pre-sheet layer structure)
The layer structure of the pre-sheet of the present invention includes a structure in which a resin layer is laminated on at least one surface of the web layer. The layer structure of the pre-sheet of the present invention includes a structure in which a resin layer is stacked on at least one surface of a laminate of a plurality of web layers. A resin layer may be disposed between the plurality of web layers.

  For example, a configuration in which a web layer and a resin layer are laminated, a configuration in which a resin layer, a web layer, and a resin layer are laminated in this order, a configuration in which a resin layer, a web layer, and a web layer are laminated in this order, A configuration in which the resin layer, the web layer, the web layer, and the resin layer are laminated in this order, and a configuration in which the resin layer, the web layer, the resin layer, the web layer, and the resin layer are laminated in this order are included in the present invention. Range.

  When a plurality of web layers are included in one pre-sheet, each web layer may be the same or different. In addition, when a plurality of resin layers are included in one pre-sheet, each resin layer may be the same or different.

  Another layer for the purpose of reinforcing the structure may be disposed between the layers.

(Reinforced fiber)
Reinforcing fibers applicable to the present invention include carbon fibers (polyacrylonitrile (PAN) -based carbon fibers, pitch-based anisotropic carbon fibers, etc.), inorganic fibers (glass fibers, basalt fibers, potassium titanate whiskers, etc.), organic Examples thereof include fibers (aramid fibers and the like).

  Among the reinforcing fibers, carbon fibers and glass fibers are preferably used because they can further increase the mechanical properties of the molded product obtained from the pre-sheet.

  The reinforcing fibers can be, for example, in the form of chopped fibers. In particular, when the web layer of the present invention is formed by the airlaid method, the reinforcing fiber can be in the form of a defibrated chopped fiber, for example.

  The average fiber length of the reinforcing fibers is preferably 1 mm or more and 100 mm or less, more preferably 2 mm or more and 80 mm or less, and further preferably 2 mm or more and 60 m or less. When the average fiber length is within the above range, the production of the web is facilitated, and the strength of the molded product is further increased.

(Chopped fiber)
Here, the chopped fiber is a short fiber from which the fiber bundle is cut. The fiber bundle is a bundle of hundreds to thousands of reinforcing fibers bundled with a binding agent such as water or resin. The defibrated chopped fiber is a large number of fibers obtained by defibrating the chopped fiber.

  As an example of the chopped fiber applicable to the present invention, for example, a chopped carbon fiber manufactured by Toho Tenax Co., Ltd. having an average fiber diameter of 4 to 10 μm and an average fiber length of 3 to 13 mm is known. . Examples of the chopped glass fibers include those made by Owens Corning having an average fiber diameter of 3 to 18 μm and an average fiber length of 1 to 20 mm. Examples of chopped aramid fibers include those manufactured by Teijin Limited in the form of shortcut fibers (fiber length 0.1 to 5 mm) and short fibers (fiber length 38 to 128 mm) mm having an average fiber diameter of 10 to 15 μm. Is mentioned.

(Thermoplastic resin)
In the present invention, the thermoplastic resin is a matrix resin in the fiber-reinforced thermoplastic.

  The thermoplastic resin applicable to the web layer of the present invention may be fibrous or particulate.

The thermoplastic resin applicable to the resin layer of the present invention may be a sheet-like material having an air permeability exceeding 0 cm ³ / cm ² · s, and may be fibrous or particulate. It may be in the form of pellets. From the viewpoint that the strength of the molded product obtained from the pre-sheet becomes higher, the thermoplastic resin is preferably fibrous.

  Examples of the thermoplastic resin include polypropylene (PP), polyethylene terephthalate (PET), nylon 6, nylon 11, nylon 12, nylon 66, nylon 610, nylon 612, nylon 6T, nylon 9T, nylon 9T, nylon M5T, and other polyamides, polycarbonates, poly Examples thereof include lactic acid and polyetherimide (PEI). Two or more thermoplastic resins may be used in combination.

  The thermoplastic resin of the web layer and the resin layer in one pre-sheet may be the same or different. It is preferable that they are the same from the viewpoint of interlayer adhesion of the press-formed body.

  When the thermoplastic resin is fibrous, the fineness of the thermoplastic fiber is preferably 1 dtex to 120 dtex, and more preferably 1 dtex to 85 dtex. Moreover, it is preferable that the average fiber length of a thermoplastic fiber is 1-50 mm, It is more preferable that it is 1-40 mm, It is further more preferable that it is 2-30 mm. When the fineness and average fiber length of the thermoplastic fibers are in the above ranges, the web layer can be easily formed and a uniform binding force and a dispersed state can be easily obtained.

  When the thermoplastic resin is in the form of particles, the average particle size of the thermoplastic particles is preferably 1 to 1,000 μm, and more preferably 10 to 800 μm.

  When the thermoplastic resin is in the form of pellets, one side is preferably 0.1 to 5 mm, and more preferably 0.5 to 5 mm.

(Heat-fusion resin)
The heat-fusible resin in the present invention, which may be blended as necessary, becomes a binder resin that binds the reinforcing fibers and the thermoplastic resin when preparing the pre-sheet. The heat-fusible resin can also be a matrix resin in fiber reinforced thermoplastics. Thus, in the present invention, both the thermoplastic resin and the heat-fusible resin can be a matrix resin in a fiber-reinforced thermoplastic, but hereinafter referred to simply as “matrix resin” in the present specification, It shall refer to a thermoplastic resin.

  The heat-fusible resin may be fibrous or particulate. Further, when the pre-sheet is manufactured by a wet method, the heat-fusible resin may have a form in which particles are dispersed in a liquid.

  Examples of the heat-fusible resin include polyethylene (PE), polypropylene, low melting point polyethylene terephthalate, low melting point polyamide, low melting point polylactic acid, polybutylene succinate, acrylic, urethane, styrene butadiene copolymer, polyvinyl alcohol (PVA), etc. Is mentioned. Two or more kinds of heat-fusible resins may be used in combination.

  When the heat-fusible resin is fibrous, the fineness of the heat-fusible fiber is preferably 1 dtex to 120 dtex, and more preferably 1 dtex to 85 dtex. Moreover, it is preferable that the average fiber length of a heat-fusible fiber is 1-100 mm, It is more preferable that it is 1-60 mm, It is further more preferable that it is 2-30 mm. When the fineness and average fiber length of the heat-fusible fiber are within the above ranges, the web layer can be easily formed, and a uniform binding force and a dispersed state can be easily obtained.

  When the heat-fusible resin is in the form of particles, the average particle size of the heat-fusible particles is preferably 10 to 1,000 μm, and more preferably 20 to 800 μm. When dispersed in an aqueous solution, the average particle size of the heat-fusible particles is preferably 10 nm to 100 μm.

(Composite of heat-fusible resin and thermoplastic resin)
The above-described thermoplastic resin and heat-fusible resin may be combined to form a composite.

  As a composite of a thermoplastic resin and a heat-fusible resin, a core-sheath fiber having a core portion made of a thermoplastic resin and a sheath portion made of a heat-fusible resin, half on one side in a cross section perpendicular to the longitudinal direction Are side-by-side fibers made of a heat-fusible resin and the other half is made of a thermoplastic resin, and core-shell particles having a core made of a thermoplastic resin and a shell made of a heat-fusible resin. Among these, core-sheath fibers are preferably used because different types of resins can be easily combined.

  As the core-sheath fiber, for example, a PP / PE composite core provided with a core part made of polypropylene fiber (melting point 160 ° C.) and a sheath part made of polyethylene (melting point 130 ° C.) formed on the outer periphery of the core part. A sheath fiber is mentioned.

  Other core sheath fibers include, for example, PET / low melting point PET composite core sheath fiber, high density polyethylene / low density polyethylene composite core sheath fiber, polyethylene / low melting point PET composite core sheath fiber, polyamide / low melting point polyamide composite. Examples include core-sheath fibers, polylactic acid / low melting point polylactic acid composite core-sheath fibers, and polylactic acid / polybutylene succinate composite core-sheath fibers.

  These composites can provide heat-fusibility due to the presence of the heat-fusible resin exposed to the outside, and can function as a binder. Therefore, these composites can be blended as a heat-fusible resin in the present invention. Moreover, since these composites contain a thermoplastic resin, it is possible to impart strength to a molded product obtained from a pre-sheet produced by containing the thermoplastic resin.

(Content ratio of each component)
When the pre-sheet does not contain a heat-fusible resin, the ratio A / B between the mass A of reinforcing fibers and the mass B of the thermoplastic resin serving as the matrix resin in the pre-sheet is, for example, 10/90 to 90 / 10 and can be 20/80 to 80/20. When the ratio A / B is in the above range, the mechanical properties of the fiber-reinforced thermoplastic obtained from the pre-sheet can be sufficiently enhanced.

  When the pre-sheet includes a heat-fusible resin, the content C of the heat-fusible resin can be 1 to 50 parts, and 2 to 15 parts, when the mass of the entire pre-sheet is 100 parts. Can do. That is, assuming that the pre-sheet is composed of reinforcing fibers, a thermoplastic resin, and a heat-fusible resin, if the entire pre-sheet is 100 parts by mass, the content C of the heat-fusible resin is 1 to 50 parts by mass. The remaining 99 parts by mass to 50 parts by mass will be allocated to the contents of the reinforcing fiber and the thermoplastic resin at the ratio A / B described above.

  When the content ratio of the heat-fusible resin in the whole pre-sheet is high, the strength of the pre-sheet when the pre-sheet is manufactured by a manufacturing method including a binding step of constituent components by heating tends to be relatively high. Moreover, when the content ratio of the heat-fusible resin in the whole pre-sheet is low, the strength after the hot-pressing process tends to be high after the hot-pressing process of the pre-sheet when manufacturing a molded product. Although this is not desired to be bound by theory, it is considered that when the content ratio of the heat-fusible resin in the entire pre-sheet is low, impurities contained in the molded product are reduced.

(Basis weight)
The basis weight of Pureshito is preferably from 40~4000g / m ^2, more preferably from 100 to 3000 g / m ^2, further preferably 200~3000g / m ^2. If the basis weight of the pre-sheet is equal to or more than the lower limit value, the number of pre-sheets stacked can be reduced and the operation can be simplified in the hot pressing step when manufacturing the molded product. On the other hand, if the basis weight of the pre-sheet is not more than the upper limit value, the pre-sheet can be easily obtained.

(Function and effect)
The pre-sheet of the present invention includes a resin layer on at least one surface. Based on the properties of the thermoplastic resin contained in the resin layer, a molded article having a good surface feeling excellent in glossiness can be obtained from the fiber-reinforced thermoplastic obtained from the pre-sheet.

In general, when resin molding is performed, if voids generated during the molding process remain inside the molded product, void cracking or peeling tends to occur. The pre-sheet of the present invention includes a resin layer having an air permeability exceeding 0 cm ³ / cm ² · s on at least one surface. Although not wishing to be bound by theory, according to the pre-sheet of the present invention, it is considered that voids generated during the molding process can easily escape to the outside, and the residual voids can be reduced. Therefore, the pre-sheet of the present invention can suppress the occurrence of cracks when molding the fiber-reinforced thermoplastic obtained from the pre-sheet, and can exhibit good moldability.

<Pre-sheet manufacturing method>
The manufacturing method of the pre-sheet of the present invention includes formation of a web layer and formation of a resin layer. For example, by a known nonwoven fabric manufacturing method such as airlaid method, wet papermaking method, spunlace method, needle punch method, etc., only a web layer without a resin layer was obtained, and separately produced from the obtained web layer A pre-sheet can be produced by laminating and integrating a sheet-like material to be a resin layer. For example, when the web layer is produced by the air laid method, the air laid carrier sheet may be a sheet-like material for the resin layer according to the present invention.

(Pre-sheet manufacturing method using airlaid method)
Next, the manufacturing method of the pre-sheet of embodiment using the airlaid method is demonstrated in detail. The manufacturing method of the pre-sheet of the present embodiment includes a defibrating process, a mixing process, a web forming process, and a binding process. Each step will be described below.

(Defibration process)
The defibrating step is a step of defibrated chopped fiber by defibrating the chopped fiber with an air flow and / or mechanical share.

  In the defibrating method using the air flow of the chopped fiber, an air flow is formed by a blower or the like, the chopped fiber is supplied to the air flow, and the chopped fiber is defibrated by the stirring effect of the air flow. According to the defibration by the air flow, it is possible to prevent the reinforcing fiber from being broken and shortened. In particular, carbon fiber and glass fiber are brittle and easily broken by mechanical shearing force, but breakage can be prevented by defibration by an air flow.

  As a defibrating method, it is preferable to defibrate with a swirling air flow. According to the defibrating method using the swirling air flow, the chopped fiber can be sufficiently defibrated. Therefore, when forming the air laid web by the air laid method, the dispersibility of the defibrated chopped fiber can be further enhanced.

  Examples of the defibrating method using the swirling air flow include a method in which chopped fiber is introduced into the blower and defibrated by the blower. Further, there is a method in which air is sent along a circumferential direction in a cylindrical container by a blower to form a swirling flow, chopped fiber is supplied into the swirling flow, and stirring to defibrate. As a method of using the air flow and the mechanical shear in combination, there is a method in which a chopped fiber hits the baffle by providing a baffle in the blower and is defibrated by the air flow and the mechanical shear. Examples of the method of defibration with a mechanical share include a method of compressing and spreading a fiber bundle with a roll and a method of carding with a roller with a needle.

  The flow rate of the airflow is appropriately selected according to the amount of chopped fiber, but is usually in the range of 10 to 150 m / sec.

(Mixing process)
The mixing step is a step of obtaining a web raw material by mixing defibrated chopped fibers, a thermoplastic resin, and a heat-fusible resin. Auxiliaries such as flame retardant added as necessary can be added in this mixing step.

  In mixing, in order to improve the dispersibility of the defibrated chopped fiber, it is preferable to stir the defibrated chopped fiber, the thermoplastic resin, and the heat-fusible resin. However, in order to prevent breakage of the defibrated chopped fiber, it is preferable to apply stirring using an air flow instead of stirring using mechanical shearing force.

  The mixing step may be after the defibrating step or at the same time as the defibrating step. When the mixing step is performed simultaneously with the defibrating step, the defibrated chopped fiber, the thermoplastic resin, and the heat-fusible resin are mixed using an air flow in the defibrating step.

(Web forming process)
A web formation process is a process of forming a web from a web raw material. In this embodiment, an air laid method is adopted to obtain an air laid web. Here, the airlaid method is a method of forming a web by randomly depositing fibers three-dimensionally using an air flow.

  In the web forming process in the present embodiment, for example, a web forming apparatus 1 shown in FIG. 2 is used. The web forming apparatus 1 includes a conveyor 10, a gas permeable endless belt 20, a fiber mixture supply unit 30, a first carrier sheet supply unit 40, a second carrier sheet supply unit 50, and a suction box 60.

  Here, the conveyor 10 includes a plurality of rollers 11. The air permeable endless belt 20 is mounted on the conveyor 10 and rotates. The fiber mixture supply means 30 supplies the fiber mixture to the gas permeable endless belt 20 together with the air flow. The first carrier sheet supply means 40 supplies the first carrier sheet 41 toward the gas permeable endless belt 20. The second carrier sheet supply means 50 supplies the second carrier sheet 51 toward the first carrier sheet 41 that has passed through the air-permeable endless belt 20. The suction box 60 sucks the air permeable endless belt 20 from the inside thereof.

  In the web forming apparatus 1, the fiber mixture supply means 30 is installed above the air permeable endless belt 20, the first carrier sheet supply means 40 is installed upstream of the air permeable endless belt 20, and the second carrier sheet. The supply means 50 is installed downstream of the air permeable endless belt 20.

  In the web forming process using the web forming apparatus 1, the rollers 10 are rotated in the same direction to drive the conveyor 10 and rotate the air permeable endless belt 20. Further, the first carrier sheet 41 is fed out from the first carrier sheet supply means 40 so as to come into contact with the permeable endless belt 20.

  Next, while sucking the permeable endless belt 20 by the suction box 60, the fiber mixture is lowered together with the air flow from the fiber mixture supply means 30, and the fiber mixture is dropped onto the first carrier sheet 41 on the permeable endless belt 20. , Deposit. Thereby, the air laid web A is formed.

  Next, the second carrier sheet 51 is supplied from the second carrier sheet supply means 50 on the air laid web A to obtain an air laid web-containing laminated sheet.

  The first carrier sheet 41 and the second carrier sheet 51 have a function as a conveying means for conveying the air laid web in the air laid method.

(Binding process)
The binding method is selected from a chemical bond method, a thermal bond method, and a multi-bond method. Either method may be selected, but the thermal bond method is often used from the viewpoint of binding properties with the reinforcing fiber. The binding step by the thermal bond method is a step of heat-treating the air laid web and binding the defibrated chopped fibers with a heat-fusible resin.

  Examples of the heat treatment of the air laid web include hot air treatment and infrared irradiation treatment, and hot air treatment is preferable from the viewpoint of low cost of the apparatus.

  As the hot air treatment, the air laid web is contacted with a through air dryer provided with a rotating drum having air permeability on the peripheral surface and heat treated (hot air circulating rotary drum method), and the air laid web is passed through a box type dryer. Examples include a method of heat treatment by passing hot air through an air laid web (hot air circulation conveyor oven method).

  The air laid web sandwiched between the first carrier sheet and the second carrier sheet to form a laminated sheet, that is, the air laid web-containing laminated sheet can be treated with hot air as it is. The first carrier sheet and the second carrier sheet can be peeled from the air laid web after the hot air treatment. In this embodiment, the first carrier sheet and the second carrier sheet were not peeled off from the air laid web, and the resin layer according to the present invention was used.

  The heat treatment temperature is preferably set to a temperature at which the heat-fusible resin melts but the thermoplastic resin does not melt. If it is such temperature, it can suppress that a thermoplastic resin melt | dissolves before shape | molding a presheet, binding | bonding defibrated chopped fiber reliably.

  After the binding step, it may be compressed through a heating roll for the purpose of finely adjusting the thickness and density of the pre-sheet.

  In the manufacturing method of the pre-sheet of this embodiment, the sheet-like thing which should become the resin layer which concerns on this invention was used for the carrier sheet which is a conveyance means of the air laid web in the air laid method. According to the manufacturing method of the present embodiment, a sheet-like material to be a resin layer is laminated on the web layer obtained by peeling the carrier sheet, following the peeling step of peeling the carrier sheet from the web layer, and the peeling step. A lamination process etc. can be skipped and the effect of working efficiency improvement is show | played.

  In this embodiment, the web forming apparatus has one fiber mixture supply means. In this web forming apparatus, a pre-sheet having a plurality of web layers may be obtained by repeating the above-described steps. Further, a plurality of fiber mixture supply means may be provided in the web forming apparatus to obtain a pre-sheet having a plurality of web layers in a single pass process. At this time, another sheet-like material for the purpose of reinforcing the resin layer or the structure may be inserted between the plurality of web layers.

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited to a following example.

[Example 1]
<Manufacture of pre-sheets>
A chopped PAN-based carbon fiber (fiber diameter: 7 μm, fiber length: 6 mm) was defibrated using a swirling jet airflow defibrating device to obtain a defibrated chopped fiber (CF). The processing wind speed in the defibrator was 45 m / min, and turbulent flow was caused by a baffle provided in the apparatus.

  Next, the obtained defibrated chopped fiber, 6 nylon fiber (fineness 3.3 dtex, fiber length 4 mm, melting point 225 ° C.), and core-sheath type heat-fusible composite fiber (PET / PET composite core-sheath fiber, core) Part melting point 260 ° C., sheath part melting point 130 ° C., fineness 2.2 dtex, fiber length 5 mm) were uniformly mixed at a ratio (mass ratio) of 50/40/10 by an air flow to obtain a fiber mixture.

Next, an air laid web was formed from the fiber mixture using the web forming apparatus 1 shown in FIG. Specifically, the first carrier sheet 41 was fed out by the first carrier sheet supply means 40 on the air-permeable endless belt 20 that is mounted on the conveyor 10 and travels. In Example 1, 6 nylon spunbonded nonwoven fabric (basis weight 30 g / m ² , air permeability 295 cm ³ / cm ² · s) was used as the first carrier sheet 41. In addition, "basis weight" is measured according to "Paper and paperboard-measuring method of basis weight" described in JIS P 8124: 2011, and "air permeability" is "fabric and knitted fabric test described in JIS L 1096: 2010". Measured according to “Method”.

While sucking the air-permeable endless belt 20 by the suction box 60, the fiber mixture was dropped and deposited on the first carrier sheet 41 together with the air flow from the fiber mixture supply means 30. At that time, the fiber mixture was supplied so that the basis weight of the airlaid web portion was 750 g / m ² . Here, the air laid web portion is a portion to be a web layer in the pre-sheet.

Next, the second carrier sheet supply unit 50 laminated the second carrier sheet 51 on the fiber mixture deposit on the first carrier sheet 41 to obtain an airlaid web-containing laminated sheet. In Example 1, 6 nylon spunbonded nonwoven fabric (basis weight 30 g / m ² , air permeability 295 cm ³ / cm ² · s) was used as the second carrier sheet 51.

The obtained laminated sheet was passed through a hot air circulating conveyor oven type box-type dryer and subjected to hot air treatment at a temperature of 140 ° C. to obtain a pre-sheet having a basis weight of 810 g / m ² . In Example 1, the 1st carrier sheet 41 and the 2nd carrier sheet 51 serve as a resin layer in a pre-sheet.

<Production of carbon fiber reinforced thermoplastic molded product>
The pre-sheet was cut into 20 cm × 20 cm, and two pieces obtained as a result were laminated and placed in a stainless steel mold having an opening of 20 cm × 20 cm and a depth of 2 mm. Next, the mold was set in a hot press, the temperature was set to the melting point of the matrix resin + 30 ° C., pre-pressed at a pressure of 2 MPa for 3 minutes, further pressurized to 5 MPa and pressed for 10 minutes. Thereafter, it was cooled at 5 MPa to obtain a carbon fiber reinforced thermoplastic molded product (first molded product).

  Specifically, in this example, since the pre-sheet contains 6 nylon as the matrix resin, the molding process was performed by setting the temperature of the hot press machine to 255 ° C., which is 30 ° C. higher than the melting point 225 ° C. . In the present invention, the pre-sheet may contain a plurality of thermoplastic resins as the matrix resin. In this case, the temperature of the hot press machine melts and decomposes the main matrix resin having the largest number of blended parts. Set the temperature at any time.

  In the same manner, a bowl-shaped mold having a height of 5 cm was used to obtain a carbon fiber reinforced thermoplastic molded article (second molded article).

[Example 2]
A pre-sheet was obtained in the same manner as in Example 1 except that the supply amount of the fiber mixture was adjusted so that the basis weight related to the air laid web portion was 1500 g / m ² . The basis weight of the obtained pre-sheet was 1560 g / m ² .

  Further, a carbon fiber reinforced thermoplastic molded article was produced in the same manner as in Example 1 except that the obtained pre-sheet was molded as a single unit.

[Example 3]
As the first carrier sheet, in the same manner as in Example 1, except that a 6 nylon spunbonded nonwoven fabric (basis weight 60 g / m ² , air permeability 115 cm ³ / cm ² · s) having different basis weight and air permeability was used. A pre-sheet was obtained. The basis weight of the obtained pre-sheet was 840 g / m ² . A carbon fiber reinforced thermoplastic molded article was produced in the same manner as in Example 1 except that the pre-sheets were laminated so that the thinner carrier sheets faced each other.

[Example 4]
Defibered chopped fiber, 6 nylon fiber, and core-sheath type heat-fusible composite fiber (PET / PET composite core-sheath fiber) were mixed at a ratio (mass ratio) of 70/20/10 to obtain a fiber mixture. Except that, a pre-sheet was obtained in the same manner as in Example 3. A carbon fiber reinforced thermoplastic molded article was produced in the same manner as in Example 1 except that the pre-sheets were laminated so that the thinner carrier sheets faced each other.

[Example 5]
6 A fiber mixture was obtained by using polycarbonate fibers (fineness 3 dtex, fiber length 5 mm, melting point 150 ° C.) instead of nylon fibers, and polycarbonate spunbond nonwoven fabric (basis weight 30 g / m ² and air permeability of 295 cm ³ / cm ² · s) were used in the same manner as in Example 1 except that a pre-sheet was obtained. Using the resulting pre-sheet, a carbon fiber reinforced thermoplastic molded article was produced in the same manner as in Example 1.

[Example 6]
6 Polypropylene spunbonded nonwoven fabric (basis weight) on the first and second carrier sheets, using polypropylene fibers (fineness 2.2 dtex, fiber length 5 mm, melting point 168 ° C.) instead of 6 nylon fibers A pre-sheet was obtained in the same manner as in Example 1 except that 30 g / m ² and air permeability of 290 cm ³ / cm ² · s) were used. Using the resulting pre-sheet, a carbon fiber reinforced thermoplastic molded article was produced in the same manner as in Example 1.

[Example 7]
6 Polyetherimide fiber (fineness: 2.2 dtex, fiber length: 5 mm, melting point: 215 ° C.) was used instead of nylon 6 fiber, and a polyetherimide spunbond was applied to the first and second carrier sheets. A pre-sheet was obtained in the same manner as in Example 1 except that a non-woven fabric (basis weight 30 g / m ² , air permeability 290 cm ³ / cm ² · s) was used. Using the resulting pre-sheet, a carbon fiber reinforced thermoplastic molded article was produced in the same manner as in Example 1.

[Example 8]
A pre-sheet was obtained in the same manner as in Example 5 except that a fiber mixture was obtained using glass fibers (fineness: 1 dtex, fiber length: 5 mm) instead of carbon fibers. A glass fiber reinforced thermoplastic molded article was produced in the same manner as in Example 1 using the obtained pre-sheet.

[Example 9]
A pre-sheet was obtained in the same manner as in Example 7 except that a fiber mixture was obtained using glass fibers (fineness 1 dtex, fiber length 5 mm) instead of carbon fibers. A glass fiber reinforced thermoplastic molded article was produced in the same manner as in Example 1 using the obtained pre-sheet.

[Example 10]
A pre-sheet was obtained in the same manner as in Example 1 except that an aramid fiber (fineness 1.7 dtex, fiber length 5 mm) was used instead of carbon fiber to obtain a fiber mixture. Using the obtained pre-sheet, an aramid fiber-reinforced thermoplastic molded article was produced in the same manner as in Example 1.

[Example 11]
Instead of laminating the two pre-sheets produced in Example 1, the same procedure as in Example 1 was conducted except that one pre-sheet produced in Example 1 and one pre-sheet produced in Example 10 were laminated. A plastic plastic molded product was produced.

[Example 12]
A pre-sheet was obtained in the same manner as in Example 1 except that the feed amount of the fiber mixture was adjusted so that the basis weight of the air laid web portion was 300 g / m ² instead of 750 g / m ² . Further, a carbon fiber reinforced thermoplastic molded article was produced in the same manner as in Example 1 except that four sheets of the obtained pre-sheets were laminated and press-molded instead of two.

[Example 13]
Instead of mixing defibrated chopped fiber, 6 nylon fiber, and core-sheath type heat-fusible composite fiber (PET / PET composite core-sheath fiber) at a ratio (mass ratio) of 50/40/10, defibrated chopped Fiber and polypropylene fibers (fineness 2.2 dtex, fiber length 5 mm, melting point 168 ° C.) were mixed at a ratio (mass ratio) of 50/50 to obtain a fiber mixture, and polypropylene was used for the first and second carrier sheets. A laminated sheet was obtained in the same manner as in Example 1 except that a spunbonded nonwoven fabric (basis weight 30 g / m ² , air permeability 290 cm ³ / cm ² · s) was used. In addition, a pre-sheet was obtained in the same manner as in Example 1 except that the obtained laminated sheet was passed through a hot air circulating conveyor oven type box type dryer and subjected to hot air treatment at a temperature of 170 ° C. Using the obtained pre-sheet, a fiber-reinforced thermoplastic molded article was produced in the same manner as in Example 1.

[Example 14]
Glass fiber (fineness: 1 dtex, fiber length: 5 mm) and polycarbonate fiber (fineness: 3 dtex, fiber length: 5 mm, melting point: 150 ° C.) so that the glass fiber and polycarbonate fiber have a ratio (mass ratio) of 55.6 / 44.4 Weighed and put into water. The amount of water was 200 times the total mass of the fibers. That is, the concentration of fibers in the obtained slurry was set to 0.5% by mass. The product name “Emanon (registered trademark) 3199” (manufactured by Kao Co., Ltd.) is added as a dispersant to the total mass (100 parts by mass) of the fiber and stirred so that the fiber is uniformly in water. A slurry (first slurry) dispersed in was prepared.

Next, a core-sheath type heat-fusible composite fiber (PET / PET composite core-sheath fiber, core melting point 260 ° C., sheath melting point 130 ° C., fineness 2.2 dtex, fiber length 5 mm) in the resulting slurry It added to water so that the density | concentration of a fiber might be 10 mass%, and it stirred and produced the slurry (2nd slurry). The first slurry is such that the glass fiber, the polycarbonate fiber, and the core-sheath type heat-fusible composite fiber (PET / PET composite core-sheath fiber) have a ratio (mass ratio) of 50/40/10. The wet web was formed using the wet papermaking method. The obtained wet web was heat-dried at a temperature of 180 ° C. to obtain a web having a basis weight of 750 g / m ² . A polycarbonate spunbonded nonwoven fabric (basis weight 30 g / m ² , air permeability 295 cm ³ / cm ² · s) was laminated on the front and back surfaces of the obtained web to obtain a pre-sheet. The basis weight of the obtained pre-sheet was 810 g / m ² . Using the obtained pre-sheet, a reinforced fiber thermoplastic molded article was produced in the same manner as in Example 1.

[Example 15]
A fiber mixture was obtained using PAN-based carbon fibers (fiber diameter 7 μm, fiber length 6 mm) instead of glass fibers, and 6 nylon fibers (fineness 3.3 dtex, fiber length 4 mm, melting point 225 ° C.) instead of polycarbonate fibers. A pre-sheet was obtained in the same manner as Example 14 except for the above. Using the resulting pre-sheet, a carbon fiber reinforced thermoplastic molded article was produced in the same manner as in Example 1.

[Comparative Example 1]
Defibered chopped fiber, 6 nylon fiber, and core-sheath type heat-fusible composite fiber (PET / PET composite core-sheath fiber) are uniformly mixed by air flow at a ratio (mass ratio) of 45/45/10. To obtain a fiber mixture. An airlaid in which the feed amount of the fiber mixture is adjusted so that the basis weight of the airlaid web portion is 750 g / m ² , and the first carrier sheet, the fiber mixture deposit, and the second carrier sheet are laminated in this order. A web-containing laminated sheet was obtained. The obtained laminated sheet was passed through a hot air circulating conveyor oven type box type dryer and treated with hot air at a temperature of 140 ° C., and then the first carrier sheet and the second carrier sheet were peeled off to obtain a pre-sheet. Using the resulting pre-sheet, a carbon fiber reinforced thermoplastic molded article was produced in the same manner as in Example 1.

[Comparative Example 2]
The same as Example 6 except that a polypropylene film (basis weight 30 g / m ² , air permeability 0 cm ³ / cm ² · s) was used as the first carrier sheet and the second carrier sheet instead of the polypropylene spunbond nonwoven fabric. Thus, a pre-sheet having a basis weight of 810 g / m ² was obtained. Using the resulting pre-sheet, a carbon fiber reinforced thermoplastic molded article was produced in the same manner as in Example 1.

<Evaluation>
About the obtained molded article, the bending elastic modulus, bending strength, and glossiness were measured by the following method to evaluate the moldability. The measurement and evaluation results are shown in Table 1.

(Measurement method of bending elastic modulus and bending strength of molded products)
Using the diamond cutter, the obtained 1st molded article was cut | judged to width 15mm and length 100mm, and the test piece was produced. After measuring the thickness of the test piece, in accordance with “Bending test method of carbon fiber reinforced plastic” described in JIS K7074, a three-point bending test was performed under the conditions of a speed of 5 mm / min and a distance between fulcrums of 80 mm, and bending elasticity The rate and bending strength were measured.

(Measurement method of gloss of molded products)
The 75 ° glossiness was measured according to the glossiness measurement method described in JIS Z8741.

(Evaluation criteria for moldability)
The presence or absence of cracks on the surface of the second molded product pressed using the bowl-shaped mold was confirmed.
Evaluation ○: Smooth surface without cracks ×: Surface with cracks and irregularities

(Measurement and evaluation results)
Molded articles obtained from the pre-sheets of Examples 1 to 15 in which the nonwoven fabric made of thermoplastic resin was laminated on the front and back surfaces of the web layer were excellent in moldability and high in gloss. On the other hand, the pre-sheet of Comparative Example 1 composed of a web layer in which a nonwoven fabric composed of a thermoplastic resin is not laminated on the front and back surfaces has low gloss. In addition, the molded product obtained from the pre-sheet of Comparative Example 2 in which a film having an air permeability of 0 cm ³ / cm ² · s made of a thermoplastic resin is laminated on the front and back surfaces of the web layer is cracked on the surface of the molded product. The sex was inferior.

  Moreover, when Example 6 and Comparative Example 2 which differ only in the air permeability of the resin layer laminated | stacked on the front and back of the web layer are compared, the molded article obtained from the pre-sheet of Example 6 is obtained from the pre-sheet of Comparative Example 2. Bending elastic modulus and bending strength were higher than those of the molded products.

  Moreover, when Examples 1, 2, and 12 in which the content ratio of the heat-fusible resin in the entire pre-sheet is different are compared, the lower the content ratio of the heat-fusible resin in the entire pre-sheet, the lower the pre-sheet at the time of manufacturing the molded product. The bending strength of the molded product was high after the hot pressing process.

DESCRIPTION OF SYMBOLS 1 Web formation apparatus 30 Fiber mixture supply means 41 1st carrier sheet 51 2nd carrier sheet A Airlaid web

Claims (9)

A web layer containing reinforcing fibers and a thermoplastic resin;
A resin layer made of a thermoplastic resin and having an air permeability exceeding 0 cm ³ / cm ² · s, the resin layer being located on at least one surface of a pre-sheet for producing a fiber-reinforced thermoplastic plastic;
A pre-sheet for producing a fiber-reinforced thermoplastic plastic, characterized in that it is a sheet formed by heat-treating a laminate comprising:   The pre-sheet for producing a fiber-reinforced thermoplastic plastic according to claim 1, wherein the web layer further includes a heat-fusible resin.   The said resin layer is a nonwoven fabric, The pre-sheet for fiber-reinforced thermoplastics preparation of Claim 1 or 2 characterized by the above-mentioned.   The said web layer is the air laid web formed by the air laid method, The pre-sheet for fiber-reinforced thermoplastics preparation of any one of Claim 1 to 3 characterized by the above-mentioned.   The said resin layer is a carrier sheet used for conveyance of the said air laid web in the said air laid method, The pre-sheet for fiber-reinforced thermoplastics preparation of Claim 4 characterized by the above-mentioned.   The pre-sheet for producing a fiber-reinforced thermoplastic according to any one of claims 1 to 5, comprising a plurality of the web layers.   A fiber-reinforced thermoplastic molded article obtained by molding a single sheet or a laminate of a pre-sheet for producing a reinforced thermoplastic plastic according to any one of claims 1 to 6. A defibrating step in which chopped fibers obtained by cutting fiber bundles made of reinforcing fibers are defibrated by air flow and / or mechanical share to obtain defibrated chopped fibers;
A mixing step of mixing the defibrated chopped fiber, the thermoplastic resin and the heat-fusible resin to obtain a web raw material;
A web forming step of obtaining a web from the web raw material;
The web on a sheet-like material made of a thermoplastic resin and having an air permeability exceeding 0 cm ³ / cm ² · s is heat-treated, and the defibrated chopped fiber and the thermoplastic resin are bound by the heat-fusible resin. The binding process
A process for producing a pre-sheet for producing a fiber-reinforced thermoplastic.   The manufacturing method according to claim 8, wherein the web forming step includes disposing the web on the sheet-like material.

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