Method for producing thermoplastic resin composite and production apparatus

Abstract

This invention provides a method for efficiently manufacturing a thermoplastic resin composite containing thermoplastic resin and fiber through pull-out molding. In the manufacturing method of this embodiment, a thermoplastic resin forming composition containing active hydrogen and diisocyanate is continuously impregnated onto a fiber (10). After impregnation, the fiber is passed through a heat-forming section (30) to polymerize the thermoplastic resin and form a thermoplastic resin composite (12). The thermoplastic resin composite (12) is then continuously pulled out from the heat-forming section (30). At this time, the heating temperature of the heat-forming section (30) is set below the glass transition temperature of the thermoplastic resin so that the thermoplastic resin of the thermoplastic resin composite (12) pulled out from the heat-forming section (30) is in a glassy state.

Description

Technical Field

[0001] This invention relates to a method and apparatus for manufacturing a thermoplastic resin composite containing thermoplastic resin and fiber. Background Technology

[0002] Fiber-reinforced plastics, which are composites containing resin and fiber, are used in a wide range of fields, primarily in the automotive industry, as a lightweight alternative to metal materials due to their superior specific strength and specific stiffness.

[0003] As a method for manufacturing fiber-reinforced plastics, for example, Patent Document 1 discloses a pull-out molding method as a continuous manufacturing method for thermosetting resin composites with thermosetting resin as the matrix. Furthermore, Patent Document 2 discloses a method in which a polyisocyanate reaction mixture, consisting of a polyol component and a polyisocyanate component, is impregnated onto fibers, the polyisocyanate reaction mixture is cured by passing it through a heated mold, and a fiber-reinforced polyisocyanate matrix composite material is then pulled out.

[0004] Thermosetting resins can impregnate fibers in their unpolymerized monomer stage, which is liquid at room temperature and has low viscosity. Therefore, even with high fiber content, the resin can be easily impregnated into the fibers, enabling continuous molding with simple equipment. However, thermosetting resins become three-dimensional cross-linked structures after polymerization (curing). After impregnation and curing with fibers, they cannot be remelted, thus having the disadvantage of not being able to be reprocessed or reused.

[0005] On the other hand, for thermoplastic resin composites, which are fiber-reinforced plastics based on thermoplastic resins, reprocessing and reuse are possible by heating and remelting the thermoplastic resin that serves as the base material. However, generally speaking, thermoplastic resins are supplied in polymeric states such as granules and films during molding, resulting in a much higher viscosity when melted compared to thermosetting resins. Therefore, it is difficult to continuously produce thermoplastic resin composites with high fiber content and good impregnation.

[0006] Therefore, in the manufacturing method of thermoplastic resin composites, there is a known method that involves passing fibers impregnated with monomers through a heated mold while simultaneously polymerizing the monomers and molding the resulting resin to obtain a thermoplastic resin composite. However, the thermoplastic resin composite immediately after being removed from the mold suffers from the problem that its matrix thermoplastic resin is soft and rubbery, making it prone to deformation. Therefore, a cooling process for curing the resin is required, for example.

[0007] As a continuous manufacturing method for thermoplastic resin composites, Patent Document 3 discloses the following: impregnating fibers in a polymeric lactam mixture, passing the impregnated fibers through a heated mold, simultaneously polymerizing the lactam monomers and molding the resulting thermoplastic polyamide resin, and continuously pulling them out of the mold using a pull-out device.

[0008] It should be noted that Patent Document 4 discloses a two-component curable composition as a matrix resin composition for forming a thermoplastic resin composite, which comprises: an active hydrogen component comprising an aromatic diamine having an alkylthio group; and a diisocyanate component comprising at least one diisocyanate selected from the group consisting of aliphatic diisocyanates, alicyclic diisocyanates and their modifiers.

[0009] Existing technical documents

[0010] Patent documents

[0011] Patent Document 1: Japanese Patent Application Publication No. 2004-074427

[0012] Patent Document 2: Japanese Patent Publication No. 2002-530445

[0013] Patent Document 3: Japanese Patent Application Publication No. 2017-007266

[0014] Patent Document 4: Japanese Patent No. 6580774 Summary of the Invention

[0015] The technical problem that the invention aims to solve

[0016] It is known to manufacture thermoplastic resin composites by impregnating the monomers of thermoplastic resins into fibers as described above, molding the resin simultaneously with polymerization, and continuously drawing it out. However, techniques for polymerizing at temperatures lower than the glass transition temperature of thermoplastic resins and then drawing it out in a glassy state are not yet known, making it difficult to efficiently manufacture thermoplastic resin composites.

[0017] In view of the above problems, the purpose of the embodiments of the present invention is to provide a manufacturing method that can efficiently manufacture thermoplastic resin composites by pull-out molding.

[0018] Technical means for solving problems

[0019] A first embodiment of the present invention is a method for manufacturing a thermoplastic resin composite containing a thermoplastic resin and a fiber, wherein the manufacturing method comprises: continuously impregnating a thermoplastic resin forming composition containing an active hydrogen component and a diisocyanate component onto a fiber; passing the fiber through a heat-forming section to polymerize the thermoplastic resin forming composition and to form a thermoplastic resin composite containing the thermoplastic resin obtained by the polymerization; and continuously pulling the thermoplastic resin composite out from the heat-forming section, wherein the heating temperature of the heat-forming section is lower than the glass transition temperature of the thermoplastic resin, and the thermoplastic resin in the thermoplastic resin composite pulled out from the heat-forming section is in a glassy state.

[0020] A second embodiment of the present invention is an apparatus for manufacturing a thermoplastic resin composite containing a thermoplastic resin and fibers. The apparatus includes: an impregnation section for impregnating fibers with a thermoplastic resin forming composition containing an active hydrogen component and a diisocyanate component; a heat-forming section for passing the fibers through the heat-forming section to polymerize the thermoplastic resin forming composition and to form a thermoplastic resin composite containing the polymerized composition; and a pull-out device for continuously pulling the thermoplastic resin composite from the heat-forming section, wherein the heating temperature of the heat-forming section is lower than the glass transition temperature of the thermoplastic resin, and the pull-out device pulls the thermoplastic resin composite, in which the thermoplastic resin is in a glassy state, from the heat-forming section.

[0021] In the above embodiments, for the composite formed by impregnating the above-mentioned thermoplastic resin forming composition with the above-mentioned fiber, the flexural modulus may be 10% or more of the flexural modulus when heated at the above-mentioned heating temperature within 5 minutes.

[0022] In the above embodiments, the heating temperature can be at least 30°C lower than the glass transition temperature of the thermoplastic resin.

[0023] In the above embodiments, the thermoplastic resin forming composition has a pot life of 30 seconds or more, which is the time until the viscosity reaches 10,000 mPa·s at a temperature of 25°C.

[0024] In the above embodiments, the active hydrogen component of the thermoplastic resin forming composition may also include an aromatic diamine having an alkylthio group, and the diisocyanate component may include at least one diisocyanate selected from the group consisting of aliphatic diisocyanates, alicyclic diisocyanates and their modifiers.

[0025] Invention Effects

[0026] According to an embodiment of the present invention, a thermoplastic resin forming composition impregnated with fibers is polymerized in a heat forming section at a temperature lower than the glass transition temperature, and a thermoplastic resin composite in a glassy state is extracted from the heat forming section. Therefore, even without a cooling process, the shape of the thermoplastic resin composite formed by the heat forming section can be maintained, allowing it to proceed to the next process such as cutting, thereby improving manufacturing efficiency. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of an apparatus for manufacturing a thermoplastic resin composite according to one embodiment.

[0028] Figure 2 This is a schematic diagram of an apparatus for manufacturing a thermoplastic resin composite according to another embodiment.

[0029] Figure 3 This is a cross-sectional photograph of the molded article after hot pressing in the embodiment. Detailed Implementation

[0030] The embodiments of the present invention will now be described in detail.

[0031] The manufacturing method of the embodiment is a method for manufacturing a thermoplastic resin composite containing thermoplastic resin and fiber.

[0032] The manufacturing method includes the following steps.

[0033] The impregnation process involves continuously impregnating the fiber with a thermoplastic resin forming composition;

[0034] The thermoforming process involves passing the impregnated fibers through a thermoforming section, thereby polymerizing the thermoplastic resin forming composition and molding a thermoplastic resin composite containing the polymerized thermoplastic resin; and

[0035] The pull-out process involves continuously pulling the thermoplastic resin composite out of the heating molding section.

[0036] Furthermore, in this manufacturing method, the heating temperature (hereinafter referred to as heating temperature T) in the thermoforming process is lower than the glass transition temperature (Tg) of the thermoplastic resin, and the thermoplastic resin of the thermoplastic resin composite pulled out from the thermoforming section is in a glassy state.

[0037] Figure 1This describes an example of a manufacturing apparatus 1 suitable for this manufacturing method. The manufacturing apparatus 1 includes: an impregnation section 20 for impregnating fibers 10 with a thermoplastic resin forming composition; a heat-forming section 30 for heating the fibers 10 impregnated with the thermoplastic resin forming composition to form a thermoplastic resin composite 12; and a pull-out device 40 for continuously pulling out the formed thermoplastic resin composite 12. More specifically, the manufacturing apparatus 1 further includes: a fiber supply section 50 for supplying fibers 10 to the impregnation section 20; and a monomer supply section 60 for supplying the thermoplastic resin forming composition to the impregnation section 20.

[0038] Thermoplastic resin composites are fiber-reinforced thermoplastic resins that use fibers as reinforcing materials and thermoplastic resins as the matrix.

[0039] Examples of fibers include those made of glass, carbon, metal, ceramic, or polymers. Any one of these fibers can be used, or a combination of two or more can be used. Alternatively, a paste or coating containing components of a composition that promotes thermoplastic resin formation can be applied to the fibers. As a form of fiber, it can be used as a continuous fiber such as filaments, fibers, rovings, or fabrics, knitted pads, non-woven pads, or other forms.

[0040] The thermoplastic resin forming composition (hereinafter, sometimes referred to as monomer mixture) is a composition used to form a thermoplastic resin, and is a mixture containing an active hydrogen component and a diisocyanate component. As the active hydrogen component, a difunctional active hydrogen is used; more specifically, a diamine and / or a diol is used. When the active hydrogen component contains a diol, the thermoplastic resin is a thermoplastic polyurethane resin; when the active hydrogen component contains a diamine, the thermoplastic resin is a thermoplastic polyurea resin; when the active hydrogen component contains both a diol and a diamine, the thermoplastic resin is a thermoplastic polyurethane-urea resin containing both urethane bonds and urea bonds in the main chain, and can be any of them. Preferably, it is a thermoplastic polyurea resin or a thermoplastic polyurethane-urea resin.

[0041] As the monomer mixture, a monomer mixture with a pot life of 30 seconds or more is preferred. This pot life is the time from mixing at 25°C until the viscosity reaches 10,000 mPa·s. By using a monomer mixture with such a long pot life, it is possible to prevent the resin from curing before reaching the thermoforming section 30. The pot life can be 100 seconds or more, or 200 seconds or more. There is no particular upper limit to the pot life; for example, it can be less than 1000 seconds.

[0042] As the monomer mixture, it is preferable to use a monomer mixture with a high glass transition temperature (Tg) of the polymerized thermoplastic resin. In this embodiment, polymerization is carried out at a temperature lower than the glass transition temperature, and the polymerization temperature is increased in order to shorten the polymerization time; therefore, a high glass transition temperature is advantageous. The glass transition temperature of the thermoplastic resin is preferably 100°C or higher, more preferably 120°C or higher, and even more preferably 150°C or higher. The upper limit of the glass transition temperature is not particularly limited; for example, it can be 220°C or lower, or 200°C or lower.

[0043] As a monomer mixture, it is preferable that when the composition is impregnated into the fiber and heated to a heating temperature T, the flexural modulus of the composite of the composition and the fiber reaches at least 10% of the flexural modulus of the fully cured thermoplastic resin composite within 5 minutes. By exhibiting sufficient mechanical properties within 5 minutes, the productivity of continuous draw molding can be improved. Here, the flexural modulus refers to the longitudinal modulus of elasticity (the slope of the stress-strain curve under elastic deformation of the material) measured in a bending test, according to JIS K7074.

[0044] There are no particular limitations on the monomer mixture having the above-mentioned properties. As one embodiment, the two-component curable composition described in Patent Document 4 can be used. Preferably, the active hydrogen component includes an aromatic diamine having an alkylthio group (a), and the diisocyanate component includes at least one diisocyanate selected from the group consisting of aliphatic diisocyanates, alicyclic diisocyanates and their modifiers (b).

[0045] As an aromatic diamine (a) having an alkylthio group, a compound having two amino groups directly bonded to the aromatic ring and an alkylthio group directly bonded to the aromatic ring is preferred. The alkylthio group is composed of -SC... n H 2n+1 (Here, n is an integer greater than or equal to 1, preferably an integer from 1 to 5) represents the group. An aromatic diamine (a) may have one alkylthio group or two or more alkylthio groups in one molecule. Preferably, it has two alkylthio groups directly bonded to the aromatic ring.

[0046] As an aromatic diamine (a), dialkylthiotoluene diamines such as dimethylthiotoluene diamine, diethylthiotoluene diamine, and dipropylthiotoluene diamine are preferred.

[0047] As an active hydrogen component, it can be used in combination with the aforementioned aromatic diamine (a) and other aromatic diamines. Examples of other diamines include: 4,4'-methylenediphenylamine, 4,4'-methylenebis(2-methylaniline), 4,4'-methylenebis(2-ethylaniline), 4,4'-methylenebis(2-isopropylaniline), 4,4'-methylenebis(2,6-dimethylaniline), 4,4'-methylenebis(2,6-diethylaniline), 4,4'-methylenebis(N-methylaniline), 4,4'-methylenebis(N-ethylaniline), 4,4'-methylenebis(N-sec-butylaniline), diethyltoluenediamine, etc. Any one of these can be used, or two or more can be used in combination.

[0048] The diamine used as the active hydrogen component is preferably an aromatic diamine (a) as the main component, preferably comprising 50% or more by mass of aromatic diamine (a), more preferably comprising 70% or more by mass of aromatic diamine (a). Furthermore, preferably comprising 15% or more by mass of aromatic diamine (a), more preferably comprising 40% or more by mass of aromatic diamine (a), and even more preferably comprising 70% or more by mass of aromatic diamine (a).

[0049] As an active hydrogen component, it can contain diols (c) together with diamines. Examples of diols (c) include: alkylene glycols such as ethylene glycol and propylene glycol; polyalkylene glycols such as diethylene glycol, triethylene glycol, dipropylene glycol, and tripropylene glycol; cyclohexanediol, bisphenol A, etc. Any one of these can be used, or two or more can be used in combination.

[0050] When diol (c) is present as the active hydrogen component, the mass ratio (a / c) of aromatic diamine (a) to diol (c) is preferably 0.1 to 30. This mass ratio (a / c) is more preferably 0.5 to 20, and even more preferably 1.0 to 10.

[0051] Active hydrogen is a difunctional component used to form thermoplastic resins, but within the range that allows the formation of thermoplastic resins, it may also contain polyamines or polyols with trifunctionality or higher.

[0052] For diisocyanate (b), examples of aliphatic diisocyanates (i.e., chain aliphatic diisocyanates) include: tetramethylene diisocyanate, dodecamethylene diisocyanate, hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2-methylpentane-1,5-diisocyanate, 3-methylpentane-1,5-diisocyanate, etc. Examples of modifiers of aliphatic diisocyanates include: isocyanate-terminated urethane prepolymers formed by reacting aliphatic diisocyanates with diols, difunctional adduct-type modifiers, and difunctional urea-formate type modifiers. Among these, at least one selected from the group consisting of hexamethylene diisocyanate (HDI) and its modifiers is preferred as the aliphatic diisocyanate.

[0053] Examples of alicyclic diisocyanates include isophorone diisocyanate (IPDI), hydrogenated xylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate (H12MDI), 1,4-cyclohexane diisocyanate, methylcyclohexylene diisocyanate, and 1,3-bis(isocyanate methyl)cyclohexane. Modifiers of alicyclic diisocyanates include isocyanate-terminated urethane prepolymers formed by reacting alicyclic diisocyanates with diols, difunctional adduct-type modifiers, and difunctional urea-formate type modifiers. Among these, at least one selected from the group consisting of isophorone diisocyanate (IPDI) and 4,4'-dicyclohexylmethane diisocyanate (H12MDI) is preferred as the alicyclic diisocyanate.

[0054] The diisocyanate (b) preferably has an isocyanate group content of 15-50% by mass. Here, the isocyanate group content refers to the mass ratio of reactive isocyanate groups (NCO) in the diisocyanate (b). The isocyanate group content can be determined according to JIS K7301-6-3.

[0055] The diisocyanate component preferably comprises 80% or more by mass of diisocyanate (b), more preferably 90% or more by mass of diisocyanate (b), even more preferably 95% or more by mass, and particularly preferably 98% or more by mass. It should be noted that, as the isocyanate reacting with the active hydrogen component, a difunctional isocyanate, i.e., a diisocyanate, can be used to form a thermoplastic resin; however, within the range where a thermoplastic resin can be obtained, a trifunctional or higher polyisocyanate may also be included.

[0056] The monomer mixture is obtained by mixing liquid A, which contains active hydrogen, with liquid B, which contains diisocyanate. By mixing these liquids A and B, the two components can be reacted and cured (i.e., polymerized), and a non-crystalline thermoplastic resin is obtained through reaction curing.

[0057] The monomer mixture may contain a catalyst to promote the reaction between the active hydrogen component and the diisocyanate component. Catalysts can be metal catalysts or amine catalysts commonly used in the manufacture of polyurethane resins. Examples of metal catalysts include tin catalysts such as dibutyltin dilaurate, dioctyltin dilaurate, and dibutyltin dioctanoate; lead catalysts such as lead octanoate, lead octenate, and lead naphthenate; and bismuth catalysts such as bismuth octanoate and bismuth neodecanoate. Examples of amine catalysts include tertiary amine compounds such as triethylenediamine. These catalysts can be used alone or in combination.

[0058] In addition to the monomer mixture, various additives such as plasticizers, flame retardants, antioxidants, hygroscopic agents, mildew inhibitors, silane coupling agents, defoamers, surface conditioners, and internal mold release agents may also be included as needed.

[0059] In the monomer mixture, the molar ratio of isocyanate groups to active hydrogen groups (NCO / active hydrogen groups) is not particularly limited and can be 1.0 or higher, 1.2 or higher, or 1.5 or higher. Alternatively, this molar ratio (NCO / active hydrogen groups) can be 2.0 or lower, 1.5 or lower, or 1.2 or lower.

[0060] In thermoplastic resin composites, the ratio of fiber to thermoplastic resin is not particularly limited. As an example, the volume content of fiber in a unit volume of thermoplastic resin composite can be 30-70% or 50-60%.

[0061] Next, refer to Figure 1 The method for manufacturing the thermoplastic resin composite of the embodiments will be described.

[0062] In the impregnation process, in the impregnation section 20, a monomer mixture supplied from the monomer supply section 60 is impregnated with fibers 10 supplied from the fiber supply section 50.

[0063] In this example, the fiber supply unit 50 gathers the fibers drawn from multiple tubes 51 together and supplies the fibers 10 to the impregnation unit 20.

[0064] In this example, the monomer supply unit 60 includes: a first tank 61 storing liquid A containing active hydrogen; a second tank 62 storing liquid B containing diisocyanate; and a mixer 63 for mixing liquid A supplied from the first tank 61 and liquid B supplied from the second tank 62. The monomer supply unit 60 supplies the monomer mixture prepared by the mixer 63 to the impregnation unit 20. The mixer 63 can be used for mixing by means of stirring blades or by means of a mixing head disposed in a static mixer.

[0065] In this example, the impregnation section 20 is composed of multiple impregnation rollers 21 and is configured to: divide the monomer mixture into multiple parts to drip onto the fiber 10 traveling via the conveyor roller 22, and use the multiple impregnation rollers 21 to impregnate the fiber 10 with the monomer mixture.

[0066] Alternatively, a heating device can be installed before the impregnation section 20 to preheat the fiber 10. Preheating allows for rapid impregnation of the monomer mixture. Furthermore, it allows the moisture absorbed by the fiber 10 to evaporate just before impregnation, more effectively removing the influence of moisture during monomer polymerization and stabilizing the polymerization reaction.

[0067] In the thermoforming process, the fiber 10, after being impregnated in the impregnation section 20, is passed through the thermoforming section 30 at a predetermined heating temperature T, thereby polymerizing the monomer mixture and molding a thermoplastic resin composite 12 containing the thermoplastic resin obtained through the polymerization. That is, the fiber 10 impregnated with the monomer mixture undergoes a polymerization reaction while being shaped by heating.

[0068] In this example, the thermoforming section 30 includes: a thermoforming mold 31 for forming the fiber 10 impregnated with the monomer mixture to a predetermined thickness and width; and a heating device 32 for heating the thermoplastic resin composite 12 drawn from the thermoforming mold 31 to promote its polymerization reaction. Alternatively, the heating device 32 may not be provided.

[0069] The set temperature of the heating molding section 30, i.e., the heating temperature T, is the polymerization temperature used to polymerize the monomer mixture. It is not particularly limited if it is a temperature lower than the glass transition temperature Tg of the thermoplastic resin obtained by polymerizing the monomer mixture (T < Tg). Preferably, the heating temperature T is at least 30°C lower than the glass transition temperature Tg of the thermoplastic resin (T < Tg - 30°C). For example, the heating temperature T can be 70–180°C, 70–160°C, or 80–150°C. The temperature set as the heating temperature T can be a single temperature or a predetermined temperature range with a temperature distribution depending on the location of the heating molding section 30. When the set heating temperature T has a range, it is preferable to set its highest temperature to be lower than the aforementioned glass transition temperature Tg, and to set this highest temperature to be at least 30°C lower than the aforementioned glass transition temperature Tg.

[0070] In the pull-out process, the thermoplastic resin composite 12 is continuously pulled out from the thermoforming section 30 using the pull-out device 40. In this example, the pull-out device 40 consists of a pair of upper and lower rollers 41, 41 that pull out the thermoplastic resin composite 12 in a manner that clamps it.

[0071] In this embodiment, as described above, since the polymerization temperature (i.e., the heating temperature T) in the thermoforming section 30 is lower than the glass transition temperature (Tg) of the thermoplastic resin, the thermoplastic resin in the thermoplastic resin composite 12 pulled out from the thermoforming section 30 is in a glassy state below the glass transition temperature. That is, at the stage after exiting the thermoforming section 30, although polymerization is not yet complete, it is in a pseudo-cured state without stickiness, and is in a state where its shape can be maintained. Therefore, the shape of the thermoplastic resin composite 12 after being pulled out is not easily deformed, and it can maintain its shape.

[0072] Additionally, although not shown, a heating device for further heating the thermoplastic resin composite 12 to promote or even complete polymerization can be provided after the aforementioned pull-out device 40. Alternatively, a cutting device such as a cutter can be provided after the pull-out device 40 or after the additional heating device to obtain sheets, channel profiles, round bars, strands of wire, etc.

[0073] exist Figure 1 In the example shown, the impregnation section 20 is composed of a plurality of impregnation rollers 21 disposed before the thermoforming mold 31, but the impregnation section may also be disposed within the thermoforming mold 31. In this case, the impregnation section is assembled at its front end as part of the thermoforming section 30. Figure 2 An example illustrating this situation.

[0074] exist Figure 2In the manufacturing apparatus 1A shown, fibers 10 fed from the bobbin 51 of the fiber supply section 50 are supplied to the thermoforming mold 31 of the thermoforming section 30 via the conveying roller 52. On the other hand, monomer mixture supplied by the monomer supply section 60 is directly injected into the thermoforming mold 31 through an injection jig 71 provided at the front end of the thermoforming mold 31, and the monomer mixture impregnates the fibers 10 within the thermoforming mold 31. Therefore, the front end of the thermoforming mold 31 also serves as the impregnation section 70.

[0075] Alternatively, an impregnation fixture, such as an impregnation roller (not shown), can be provided inside the thermoforming mold 31. This allows the monomer mixture injected into the thermoforming mold 31 via the injection fixture 71 to impregnate the fiber 10 in a short time. This method of impregnating section 70 effectively impregnates the fiber 10 with the monomer mixture while simultaneously removing residual air. The air inside the fiber 10 is rapidly expelled, thus reducing the presence of tiny voids (cavities) inside the cured thermoplastic resin composite 12.

[0076] According to the above-described embodiments, thermoplastic resin composites can be manufactured efficiently through continuous pull-out molding.

[0077] In detail, generally speaking, in continuous draw molding, the resin is polymerized and cured by heating in the heating forming section. Therefore, the temperature of the thermoplastic resin composite at the exit of the heating forming section is approximately equal to the polymerization temperature of the resin set by the heating forming section. Thus, in continuous draw molding, if the polymerization temperature is higher than the glass transition temperature of the resin that forms the matrix, the thermoplastic resin composite at the exit of the heating forming section is in a soft rubber state, unable to maintain the cross-sectional shape of the thermoplastic resin composite molded article, making molding difficult. In contrast, a cooling process can be added after heating molding to cool it below the glass transition temperature, but this correspondingly increases the size of the equipment, and if the draw speed of the thermoplastic resin composite is not slowed down, it cannot be cooled to the interior of the thermoplastic resin composite, resulting in poor manufacturing efficiency.

[0078] According to this embodiment, polymerization is performed in a thermoforming section at a temperature lower than the glass transition temperature, and the thermoplastic resin composite in the glass state is pulled out from the thermoforming section. Therefore, it is easy to maintain the shape of the thermoplastic resin composite formed by the thermoforming section, thereby improving manufacturing efficiency.

[0079] Furthermore, in the continuous pull-out molding of the thermoplastic resin composite disclosed in Patent Document 3, using a polyamide resin made from a polymeric lactam mixture as the matrix cannot avoid the reduction in strength caused by moisture absorption, a drawback of polyamide resins. Additionally, the catalytic activity of the anionic catalyst ε-caprolactam, which is a raw material for the polymeric lactam mixture, is deactivated by moisture in the air, potentially hindering polymerization. In contrast, in this embodiment, by using a polyurethane and / or polyurea thermoplastic resin containing active hydrogen and diisocyanate components as the matrix, a stable and continuous production of the thermoplastic resin composite can be achieved.

[0080] The thermoplastic resin composite obtained by the manufacturing method of this embodiment can be used as various lightweight structural components through secondary processing such as hot pressing after laminating multiple sheets. In this case, compared with fiber-reinforced composite materials using thermosetting resins as the base material, the thermoplastic resin composite using the thermoplastic resin of this embodiment as the base material can shorten the secondary molding time and can be expected to achieve high productivity. It can be used as an intermediate material for various components, primarily automotive structural components requiring recyclability, and as a substitute for metal materials used to reduce weight.

[0081] Example

[0082] use Figure 1 The manufacturing apparatus 1 shown is used for the continuous drawing-out manufacturing of thermoplastic resin composites. Carbon fiber (Toray Industries, Inc. "T700SC-24000-60E") is used as fiber 10.

[0083] As a monomer mixture, a two-component curable composition (Daiichi Kogyo Pharmaceutical Co., Ltd. "H-6FP22") containing liquid A containing dialkylthiotoluene diamine and liquid B containing an aliphatic diisocyanate modifier is used.

[0084] The pot life of the two-component curable composition was determined to be 300 seconds. In the pot life determination, the time to reach 10,000 mPa·s was calculated using a BM type rotational viscometer at 25°C, rotor No. 4, and 60 rpm.

[0085] For this two-component curable composition, the glass transition temperature of the polymerized resin was measured, and the result was 175°C. The method for determining the glass transition temperature is described below.

[0086] Glass transition temperature

[0087] Solution A and solution B were adjusted to 25°C and stirred for 1 minute. The resulting monomer mixture was coated into sheets and treated at 120°C for 3 hours to obtain resin sheets with a thickness of 2 mm. 5 mm × 2 cm test pieces were cut from the resin sheets, and the glass transition temperature (Tg) was determined using a Rheogel E-4000 (manufactured by UBM) under the following conditions: chuck spacing 20 mm, fundamental frequency 10 Hz, and strain in automatic control mode.

[0088] To confirm whether the flexural modulus of the impregnated composite is at least 10% of the flexural modulus of fully cured composite after heating for less than 5 minutes, the following test was conducted. Specifically, the two-component curable composition was impregnated with fiber 10 and heated at 130°C for 5 minutes, and the flexural modulus of the composite after heating was measured. Additionally, the two-component curable composition was impregnated with fiber 10 and heated at 130°C for 10 minutes to achieve complete curing (i.e., polymerization complete), and the flexural modulus of the thermoplastic resin composite after complete curing was measured. The results showed that the flexural modulus of the composite after heating for 5 minutes was 20% of the flexural modulus of the composite after complete curing. Therefore, for this two-component curable composition, the flexural modulus of the composite reaches at least 10% of the flexural modulus of fully cured composite after heating for less than 5 minutes, confirming that the time required to exhibit sufficient mechanical properties is less than 5 minutes. The flexural modulus was measured according to JIS K7074.

[0089] The monomer mixture is supplied using the monomer supply section 60 to achieve a volume content (V) of fiber 10 in the thermoplastic resin composite 12. f The polymerization rate reaches 60%. Specifically, liquid A and liquid B are fed from tanks 61 and 62 according to a specific ratio, and stirred by a mixer 63 containing a static mixer to prepare a monomer mixture. Since the polymerization reaction begins the instant the monomer mixture is stirred, a continuous supply of new monomer mixture is required before the usable life is reached in order to achieve continuous pull-out molding, causing any stagnant monomer mixture to flow out. Therefore, the monomer mixture is added at three points to promote the flow of stagnant monomer mixture. Then, in the impregnation section 20 containing multiple impregnation rollers 21, the monomer mixture is impregnated onto fibers 10 supplied from the fiber supply section 50.

[0090] As the thermoforming mold 31, an aluminum alloy mold is used. To prevent a rapid curing reaction of the monomer mixture remaining near the mold inlet where the fiber 10 is fed in, a water-cooling pipe is installed at the mold inlet to maintain the temperature near the mold inlet at around 25°C. Furthermore, to prevent the thermoforming mold 31 from adhering to the thermoplastic resin composite 12 in the curing reaction, a thin PTFE core with upper and lower sections is provided inside the aluminum alloy thermoforming mold 31 in the portion in contact with the thermoplastic resin composite 12. Using this thermoforming mold 31, a thermoplastic resin composite 12 with a width of 15 mm and a thickness of 0.5 mm is formed within the thermoforming mold 31, which has a temperature distribution of 80°C to 130°C.

[0091] The thermoplastic resin composite 12, pulled out from the thermoforming mold 31 using the pull-out device 40, is further heated and cured in a far-infrared heater, i.e., a heating device 32. The heating temperature of the heating device 32 is 110–120°C. In this example, the length of the heating device 32 is variable, and is set to 1.0 m. The length of the thermoforming mold 31 is 0.5 m; therefore, the length of the thermoforming section 30 after adding the heating device 32 is 1.5 m. To ensure a polymerization time of 3 minutes (i.e., to ensure a polymerization time of 3 minutes from the thermoforming mold 31 to the heating device 32), the traction speed is 500 mm / min.

[0092] In this embodiment, the glass transition temperature of the resin after polymerization of the monomer mixture is 175°C. In contrast, the heating temperature T in the thermoforming section 30 is 80-130°C. Therefore, the heating temperature T is more than 30°C lower than the glass transition temperature. Thus, during the stage of being pulled out from the thermoforming section 30, the thermoplastic resin composite 12 is in a glassy state below the glass transition temperature, i.e., it undergoes pseudo-curing.

[0093] The thermoplastic resin composite 12, pulled out by the pull-out device 40, is cut into 30cm lengths. Then, to ensure more complete polymerization of the thermoplastic resin composite 12, it is heated in an oven at 120°C for 60 minutes to obtain a fully cured thermoplastic resin composite (prepreg). Using the obtained prepreg, tensile test pieces are prepared by hot pressing at 200°C and 2MPa for 10 minutes.

[0094] The fiber volume content of the obtained tensile test specimens was determined by the combustion method, and the result was that the fiber volume content was 56%. The determination of fiber volume content by the combustion method was carried out in accordance with JIS K7052.

[0095] In addition, the cross-section of this tensile test specimen was measured using an optical microscope (OLYMPUS GX51). The results were as follows: Figure 3 As shown, no internal air bubbles (voids) were observed, confirming the ability to mold thermoplastic resin composites of very high quality. Figure 3 In the image, the dark gray portion is the thermoplastic resin matrix, and the white portion is carbon fiber.

[0096] Thus, by hot-pressing the thermoplastic resin composite 12 of the embodiment at a temperature approximately 30°C higher than the glass transition temperature, a beautiful molded article without interlayer bubbles can be obtained. This means that the continuously pull-out molded thermoplastic resin composite 12 can be easily reprocessed into molded articles of any shape.

[0097] The tensile strength of the above-mentioned tensile test specimens was measured, and the measured value was compared with the theoretical value. The measured tensile strength was 2500 MPa. The tensile test was conducted according to JIS K7165. The test specimen dimensions were 240 mm in length, 15 mm in width, and 0.5 mm in thickness. Aluminum sheets were bonded to both sides of the molded part at 40 mm intervals at both ends to prevent damage caused by stress concentration at the chuck. The tensile testing machine used a servo pulse generator (Servo Pulser, Shimadzu Corporation, EFH-EG100KN-20L) at a test speed of 2 mm / s.

[0098] The theoretical value is assumed to be completely bonded to the thermoplastic resin and carbon fiber, and is calculated using the composite rule shown in the following formula.

[0099] [Number 1]

[0100] σ c =ασ fu V f +(σ m ) fu (1-V f )

[0101] In the formula, σ c These are theoretical values. α is a coefficient determined by fiber morphology (α = 1.0 in the case of unidirectional reinforcement), σ fu It is the tensile failure stress of the fiber, (σ m ) fu V is the resin breaking stress relative to the fiber breaking elongation. f It is the fiber volume content.

[0102] As a result, the theoretical tensile strength is 2750 MPa. Thus, the thermoplastic resin composite of the embodiment exhibits approximately 90% of the high strength compared to the theoretical strength, and was molded to a very high quality.

[0103] Thus, the method for manufacturing thermoplastic resin composites according to the embodiments can stably produce high-quality thermoplastic resin composites free of bubbles (voids). Because it is a continuous film-forming process, the productivity is high, and the curing reaction rate of the thermoplastic resin composite can be adjusted to regulate the product's productivity. Furthermore, it demonstrates that reprocessing and secondary forming can be performed at very low temperatures through two stamping processes, enabling high-productivity and simple manufacturing even for complex-shaped molded products.

[0104] The foregoing has described several embodiments of the present invention, but these embodiments are given by way of example only and are not intended to limit the scope of the invention. These embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments, as well as their omissions, substitutions, and modifications, are included in the scope or spirit of the invention, and are also included in the scope of the invention as described in the claims and its equivalents.

Claims

1. A method for manufacturing a thermoplastic resin composite, characterized in that, It is a method for manufacturing thermoplastic resin composites containing thermoplastic resins and fibers. The manufacturing method includes: A thermoplastic resin forming composition containing active hydrogen and diisocyanate is continuously impregnated onto fibers; The fibers are passed through a heating molding section to polymerize the thermoplastic resin forming composition and to mold a thermoplastic resin composite containing the thermoplastic resin obtained by the polymerization. as well as The thermoplastic resin composite is continuously pulled out from the heat-forming section. The heating temperature of the heat-forming section is lower than the glass transition temperature of the thermoplastic resin. The thermoplastic resin in the thermoplastic resin composite pulled out from the heating molding section is in a glassy state.

2. The method for manufacturing the thermoplastic resin composite according to claim 1, wherein, For a composite formed by impregnating the fiber with the thermoplastic resin forming composition, when heated at the heating temperature, the flexural modulus reaches more than 10% of the flexural modulus at full curing within 5 minutes.

3. The method for manufacturing the thermoplastic resin composite according to claim 1, wherein, The heating temperature is more than 30°C lower than the glass transition temperature of the thermoplastic resin.

4. The method for manufacturing the thermoplastic resin composite according to claim 2, wherein, The heating temperature is more than 30°C lower than the glass transition temperature of the thermoplastic resin.

5. The method for manufacturing the thermoplastic resin composite according to any one of claims 1 to 4, wherein, The pot life of the thermoplastic resin forming composition is 30 seconds or more, and the pot life is the time until the viscosity reaches 10,000 mPa·s at a temperature of 25°C.

6. The method for manufacturing the thermoplastic resin composite according to any one of claims 1 to 4, wherein, The active hydrogen component of the composition for forming the thermoplastic resin comprises an aromatic diamine having an alkylthio group. The diisocyanate component comprises at least one diisocyanate selected from the group consisting of aliphatic diisocyanates, alicyclic diisocyanates and their modifiers.

7. An apparatus for manufacturing a thermoplastic resin composite, characterized in that, It is a manufacturing apparatus for thermoplastic resin composites containing thermoplastic resin and fibers. The manufacturing apparatus includes: The impregnation section is formed by continuously impregnating the fiber with a thermoplastic resin composition containing active hydrogen and diisocyanate components; The heating forming section allows the fibers to pass through, thereby polymerizing the thermoplastic resin forming composition and forming a thermoplastic resin composite containing the thermoplastic resin obtained by the polymerization. as well as The pull-out device continuously pulls the thermoplastic resin composite out of the thermoforming section. The heating temperature of the heat-forming section is lower than the glass transition temperature of the thermoplastic resin. The pull-out device pulls the thermoplastic resin composite, in the glass state, out of the thermoforming section.

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