Fiber-reinforced resin sheet and method for producing the same

Abstract

To provide a fiber-reinforced resin sheet having excellent sewing resistance and a method for producing the same.SOLUTION: A fiber-reinforced resin sheet comprises a fiber aggregate including reinforcing fibers and a resin impregnated in at least one surface of the fiber aggregate. The resin comprises a first polyurethane resin which does not contain a urea bond or a crosslinked structure and a second polyurethane resin which contains a urea bond and / or a crosslinked structure. The fiber-reinforced resin sheet comprises a first complex region and a second complex region. The first complex region comprises the reinforcing fibers and a first resin component impregnated in the reinforcing fibers. The first resin component comprises the first polyurethane resin as the main component. The second complex region comprises the reinforcing fibers and a second resin component impregnated in the reinforcing fibers. The second resin component comprises the second polyurethane resin as the main component.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a fiber-reinforced resin sheet and a method for producing the same. [Background technology]

[0002] Fiber-reinforced plastics are known. Fiber-reinforced plastics contain fibers and resin impregnated into the fibers. Molded products of fiber-reinforced plastics have excellent strength. Furthermore, molded products of fiber-reinforced plastics have a property of being difficult to bend.

[0003] On the other hand, depending on the application, fiber reinforced plastics may be required to have a property of being easily bent (flexibility).Furthermore, fiber reinforced plastics may be required to have a property of being easily restored after bending (flex recovery).Therefore, resin-impregnated reinforced fiber sheets have been considered as fiber reinforced plastics.The resin-impregnated reinforced fiber sheet is a composite sheet formed by impregnating a woven fabric made of reinforcing fibers with a thermoplastic resin.

[0004] More specifically, the following carbon fiber reinforced resin processed sheet has been proposed as a resin-impregnated reinforced fiber sheet. This carbon fiber resin processed sheet is produced by laminating a thermoplastic elastomer film or a rubber film on both sides of a carbon fiber fabric. Furthermore, a polyurethane-based thermoplastic elastomer is exemplified as the thermoplastic elastomer (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-179667 Summary of the Invention [Problem to be solved by the invention]

[0006] On the other hand, in the carbon fiber resin processed sheet, a thermoplastic elastomer film or a rubber film is directly laminated to the carbon fiber fabric. In such cases, the carbon fiber resin processed sheet may not have sufficient sewing resistance. More specifically, the needle used for sewing may cause the carbon fiber fabric and the thermoplastic elastomer film or the rubber film to separate, resulting in whitening.

[0007] The present invention relates to a fiber reinforced resin sheet having excellent sewing resistance, and a method for producing the same. [Means for solving the problem]

[0008] The present invention [1] provides a fiber-reinforced resin sheet comprising a fiber aggregate containing reinforcing fibers and a resin impregnated on at least one side of the fiber aggregate, wherein the resin comprises a first polyurethane resin that does not contain urea bonds and crosslinked structures, and a second polyurethane resin that contains urea bonds and / or crosslinked structures. The fiber-reinforced resin sheet has a first composite region and a second composite region, wherein the first composite region comprises the reinforcing fibers and a first resin component impregnated into the reinforcing fibers, the first resin component comprising the first polyurethane resin as a main component, and the second composite region comprises the reinforcing fibers and a second resin component impregnated into the reinforcing fibers, and the second resin component comprises the second polyurethane resin as a main component.

[0009] The present invention [2] includes the fiber-reinforced resin sheet according to the above [1], further comprising a fiber region containing the reinforcing fibers and substantially not containing the resin, the second composite region being arranged on at least one side of the fiber region, and the first composite region being arranged on the opposite side of the second composite region from the side on which the fiber region is arranged.

[0010] The present invention [3] includes the fiber-reinforced sheet according to the above [1] or [2], in which the second polyurethane resin contains a urea bond.

[0011] The present invention [4] includes the fiber-reinforced sheet according to any one of the above [1] to [3], wherein the second polyurethane resin contains a urea bond and a crosslinked structure.

[0012] The present invention [5] includes the fiber-reinforced sheet according to any one of the above [1] to [4], wherein the first polyurethane resin includes a reaction product of a first raw material component including a diisocyanate component and a diol component, and the diisocyanate component includes a monocyclic alicyclic diisocyanate.

[0013] The present invention [6] includes the fiber-reinforced resin sheet according to the above [5], in which the monocyclic alicyclic diisocyanate includes 1,4-bis(isocyanatomethyl)cyclohexane.

[0014] The present invention [7] includes the fiber-reinforced resin sheet according to the above [6], wherein the 1,4-bis(isocyanatomethyl)cyclohexane contains trans isomers in a proportion of 80 mol % or more.

[0015] The present invention [8] includes the fiber-reinforced resin sheet according to any one of the above [5] to [7], wherein the diol component contains a macrodiol and the number average molecular weight of the macrodiol is 400 or more and 3000 or less.

[0016] The present invention [9] includes the fiber-reinforced resin sheet according to any one of the above [1] to [8], wherein the hard segment concentration of the first polyurethane resin is 8% by mass or more and 55% by mass or less.

[0017] The present invention

[10] includes the fiber-reinforced resin sheet according to any one of the above [1] to [9], wherein the urethane group concentration of the first polyurethane resin is 1.7 mmol / g or more and 4.5 mmol / g or less.

[0018] The present invention

[11] includes the fiber-reinforced resin sheet according to any one of the above [1] to

[10] , in which the first polyurethane resin satisfies the following formula (1):

[0019] Equation (1): 0<[heat release amount of urethane group recrystallization peak (mJ / mg) ÷ heat release interval (°C)]<0.85

[0020] The present invention

[12] includes the fiber-reinforced resin sheet according to any one of the above [1] to

[11] , wherein the reinforcing fibers include carbon fibers and / or aramid fibers.

[0021] The present invention

[13] includes a method for producing a fiber-reinforced resin sheet, comprising: a preparation step of preparing a fiber aggregate containing reinforcing fibers and a polyurethane laminate sheet; a contact step of contacting the polyurethane laminate sheet with the fiber aggregate containing reinforcing fibers; and a pressing step of heating and pressurizing the fiber aggregate containing reinforcing fibers and the polyurethane laminate sheet, wherein the polyurethane laminate sheet is formed by laminating a first polyurethane resin that does not contain urea bonds or crosslinked structures and a second polyurethane resin that contains urea bonds and / or crosslinked structures; in the contact step, the second polyurethane resin is arranged so as to contact the fiber aggregate; and in the pressing step, the first polyurethane resin and the second polyurethane resin are melted and impregnated into the fiber aggregate.

[0022] The present invention

[14] includes the method for producing a fiber-reinforced resin sheet described in the above

[13] , wherein the preparation step includes a film preparation step of preparing a film of the first polyurethane resin, and a coating step of coating the film with the second polyurethane resin and / or its precursor. [Effects of the Invention]

[0023] The fiber-reinforced resin sheet of the present invention comprises a fiber assembly and a resin impregnated into the fiber assembly. The resin comprises a first polyurethane resin that does not contain urea bonds or crosslinked structures, and a second polyurethane resin that contains urea bonds and / or crosslinked structures. The fiber-reinforced resin sheet also comprises a first composite region and a second composite region. The first composite region comprises reinforcing fibers and a first resin component, the first resin component containing the first polyurethane resin as a main component. The second composite region comprises reinforcing fibers and a second resin component, the second resin component containing the second polyurethane resin as a main component. Such a fiber-reinforced resin sheet has excellent sewing durability.

[0024] In the method for producing a fiber-reinforced resin sheet of the present invention, a polyurethane laminate sheet is brought into contact with a fiber assembly containing reinforcing fibers, and the two are heated and pressurized. The polyurethane laminate sheet is formed by laminating a first polyurethane resin that does not contain urea bonds or crosslinked structures and a second polyurethane resin that contains urea bonds and / or crosslinked structures. The second polyurethane resin is arranged so as to contact the fiber assembly. The first polyurethane resin and the second polyurethane resin are melted and impregnated into the fiber assembly. This method for producing a fiber-reinforced resin sheet can produce a fiber-reinforced resin sheet with excellent sewing resistance. [Brief explanation of the drawings]

[0025] [Figure 1] 1A to 1D are schematic diagrams showing one embodiment of a fiber-reinforced resin sheet of the present invention and a method for producing the same. FIG. 1A shows a step of preparing a film of a first polyurethane resin. FIG. 1B shows a step of coating a film of the first polyurethane resin with a second polyurethane and / or its precursor. FIG. 1C shows a step of contacting a polyurethane laminate sheet with a fiber assembly. FIG. 1D shows a step of heating and pressurizing the fiber assembly and polyurethane laminate sheet. [Figure 2] FIG. 2 is a schematic view showing another embodiment of the fiber-reinforced resin sheet of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0026] 1. Fiber reinforced resin sheet The fiber-reinforced resin sheet of the present invention includes a fiber aggregate containing reinforcing fibers and a resin impregnated into at least one surface of the fiber aggregate.

[0027] (1) Fiber assembly Examples of reinforcing fibers include carbon fibers, glass fibers, aramid fibers, alumina fibers, silicon carbide fibers, boron fibers, metal fibers, and cellulose nanofibers. The reinforcing fibers can be used alone or in combination of two or more types. Preferred examples of reinforcing fibers include carbon fibers, glass fibers, and aramid fibers, and more preferred examples include carbon fibers and aramid resins. That is, the reinforcing fibers preferably include carbon fibers and / or aramid fibers. The use of carbon fibers and / or aramid fibers can improve mechanical properties. Carbon fibers are particularly preferred examples of reinforcing fibers. The use of carbon fibers can improve design.

[0028] Examples of carbon fibers include pitch-based carbon fibers, polyacrylonitrile (PAN)-based carbon fibers, and rayon-based carbon fibers. Carbon fibers can be used alone or in combination of two or more types. PAN-based carbon fibers are preferred as carbon fibers.

[0029] The fiber aggregate containing reinforcing fibers is formed by molding a fiber material containing reinforcing fibers into a sheet shape by a known method. The fiber material may contain fibers other than the reinforcing fibers in an appropriate ratio. The fiber material preferably contains only reinforcing fibers. That is, the fiber aggregate is preferably made of reinforcing fibers.

[0030] Examples of fiber assemblies containing reinforcing fibers include woven fabrics, knitted fabrics, felts, nonwoven fabrics, and unidirectional materials. These can be used alone or in combination of two or more. From the viewpoint of flexural recovery, a preferred fiber assembly is a woven fabric.

[0031] The manufacturing method of the woven fabric is not particularly limited, and examples thereof include plain weave, twill weave, satin weave, saty weave, and checkered weave. Examples of the woven fabric include plain weave, twill weave, satin weave, saty weave, and checkered weave. Examples of the woven fabric include uniaxial weave and multiaxial weave. These can be used alone or in combination of two or more types. Preferred examples of the woven fabric made of reinforcing fibers include plain weave and twill weave.

[0032] The thickness of the fiber assembly of reinforcing fibers is, for example, 50 μm or more, or preferably 100 μm or more, and for example, 1000 μm or less, or preferably 500 μm or less.

[0033] (2) Resin The resin includes a first polyurethane resin and a second polyurethane resin.

[0034] (A) First polyurethane resin The first polyurethane resin is a polyurethane resin that does not contain a urea bond or a crosslinked structure.

[0035] The first polyurethane resin includes, for example, a reaction product of a first raw material component, which includes, for example, a first polyisocyanate component and a first active hydrogen group-containing component.

[0036] The first polyisocyanate component is a component containing one or more isocyanate groups in one molecule. The first active hydrogen group-containing component is a component containing one or more active hydrogen groups in one molecule.

[0037] Examples of active hydrogen groups include hydroxyl groups and amino groups. The first active hydrogen group-containing component containing a hydroxyl group is referred to as the first polyol component. The first active hydrogen group-containing component containing an amino group is referred to as the first amine component.

[0038] The first polyisocyanate component may be a polyisocyanate having an average number of isocyanate groups of 2 (hereinafter referred to as a diisocyanate component).

[0039] That is, the first polyurethane resin does not contain a crosslinked structure. Therefore, the first polyisocyanate component does not contain a polyisocyanate component with an average number of isocyanate groups exceeding 2. Preferably, the first polyisocyanate component is made of a diisocyanate component.

[0040] Examples of the diisocyanate component include alicyclic diisocyanates, chain aliphatic diisocyanates, aromatic diisocyanates, and araliphatic diisocyanates.

[0041] Examples of the alicyclic diisocyanate include monocyclic alicyclic diisocyanates and polycyclic alicyclic diisocyanates.

[0042] Examples of monocyclic alicyclic diisocyanates include monocyclic alicyclic diisocyanate monomers. Monocyclic alicyclic diisocyanate monomers are polyisocyanate monomers containing one alicyclic ring and two isocyanate groups per molecule. Examples of monocyclic alicyclic diisocyanate monomers include 1,4-cyclopentene diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, 1,4-bis(isocyanatomethyl)cyclohexane, 1,3-bis(isocyanatomethyl)cyclohexane, and isophorone diisocyanate. These can be used alone or in combination of two or more types.

[0043] Examples of polycyclic alicyclic diisocyanates include polycyclic alicyclic diisocyanate monomers. Polycyclic alicyclic diisocyanate monomers are polyisocyanate monomers containing two or more alicyclic rings and two isocyanate groups in one molecule. Examples of polycyclic alicyclic diisocyanate monomers include norbornene diisocyanate (NBDI) and methylenebis(cyclohexylisocyanate) (H 12 These can be used alone or in combination of two or more types.

[0044] Examples of the chain aliphatic diisocyanate include chain aliphatic diisocyanate monomers. Chain aliphatic diisocyanate monomers are polyisocyanate monomers that contain two isocyanate groups per molecule and do not contain an aromatic ring or an alicyclic ring. Examples of the chain aliphatic diisocyanate monomers include ethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate (PDI), and hexamethylene diisocyanate (HDI). These can be used alone or in combination of two or more types.

[0045] Examples of aromatic diisocyanates include aromatic diisocyanate monomers. Examples of aromatic diisocyanate monomers include diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), toluidine diisocyanate (TODI), paraphenylene diisocyanate, and naphthalene diisocyanate (NDI). These can be used alone or in combination of two or more.

[0046] The araliphatic diisocyanate may be an araliphatic diisocyanate monomer. Examples of the araliphatic diisocyanate monomer include xylylene diisocyanate (XDI) and tetramethylxylylene diisocyanate (TMXDI). These may be used alone or in combination of two or more.

[0047] From the viewpoint of mechanical strength, the first polyisocyanate component (diisocyanate component) is preferably an alicyclic diisocyanate, more preferably a monocyclic alicyclic diisocyanate. In other words, from the viewpoint of mechanical strength, the first polyisocyanate component (diisocyanate component) preferably contains an alicyclic diisocyanate, more preferably a monocyclic alicyclic diisocyanate.

[0048] The content of the monocyclic alicyclic diisocyanate relative to the total amount of the first polyisocyanate component (diisocyanate component) is, for example, more than 50 mol%, preferably 70 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more, and particularly preferably 100 mol%.

[0049] That is, from the viewpoint of mechanical strength, the first polyisocyanate component (diisocyanate component) preferably does not contain any other polyisocyanate and is made of a monocyclic alicyclic diisocyanate.

[0050] From the viewpoint of mechanical strength, more preferred examples of the monocyclic alicyclic diisocyanate include 1,4-bis(isocyanatomethyl)cyclohexane and 1,3-bis(isocyanatomethyl)cyclohexane. In other words, from the viewpoint of mechanical strength, the monocyclic alicyclic diisocyanate more preferably includes 1,4-bis(isocyanatomethyl)cyclohexane and / or 1,3-bis(isocyanatomethyl)cyclohexane.

[0051] 1,4-bis(isocyanatomethyl)cyclohexane is classified into cis-1,4-bis(isocyanatomethyl)cyclohexane and trans-1,4-bis(isocyanatomethyl)cyclohexane. In the following, cis-1,4-bis(isocyanatomethyl)cyclohexane will be referred to as the cis isomer or cis 1,4 isomer. Trans-1,4-bis(isocyanatomethyl)cyclohexane will be referred to as the trans isomer or trans 1,4 isomer. The total amount of the trans 1,4 isomer and the cis 1,4 isomer is 100 mol%.

[0052] 1,4-bis(isocyanatomethyl)cyclohexane preferably contains the trans-1,4 isomer. The content of the trans-1,4 isomer relative to the total moles of 1,4-bis(isocyanatomethyl)cyclohexane is, for example, 60 mol% or more, preferably 70 mol% or more, more preferably 75 mol% or more, and even more preferably 80 mol% or more. Furthermore, the content of the trans-1,4 isomer relative to the total moles of 1,4-bis(isocyanatomethyl)cyclohexane is, for example, 99.5 mol% or less, preferably 99 mol% or less, more preferably 96 mol% or less, and even more preferably 90 mol% or less. When the content of the trans-1,4 isomer is equal to or greater than the above lower limit, excellent heat resistance can be obtained.

[0053] In other words, the content of cis-1,4 isomer relative to the total moles of 1,4-bis(isocyanatomethyl)cyclohexane is, for example, 0.5 mol% or more, preferably 1 mol% or more, more preferably 4 mol% or more, and even more preferably 10 mol% or more. Also, the content of cis-1,4 isomer relative to the total moles of 1,4-bis(isocyanatomethyl)cyclohexane is, for example, 40 mol% or less, preferably 30 mol% or less, more preferably 25 mol% or less, and even more preferably 20 mol% or less.

[0054] 1,4-bis(isocyanatomethyl)cyclohexane is produced by a known method, as described in, for example, International Publication Nos. WO2009 / 051114 and WO2019 / 069802.

[0055] The first polyisocyanate component may contain other polyisocyanates as optional components, provided that the excellent effects of the present invention are not impaired. The other polyisocyanates are polyisocyanates other than monocyclic alicyclic polyisocyanates. Examples of other polyisocyanates include polycyclic alicyclic polyisocyanates, linear aliphatic polyisocyanates, aromatic polyisocyanates, and araliphatic polyisocyanates.

[0056] From the viewpoint of mechanical strength, the monocyclic alicyclic diisocyanate is particularly preferably 1,4-bis(isocyanatomethyl)cyclohexane. In other words, from the viewpoint of mechanical properties, the first polyisocyanate component is particularly preferably composed of 1,4-bis(isocyanatomethyl)cyclohexane.

[0057] The first active hydrogen group-containing component is, for example, composed of a first polyol component and does not contain a first amine component. That is, the first polyurethane resin does not contain a urea bond. Therefore, the first active hydrogen group-containing component preferably does not contain a first amine component.

[0058] The first polyol component may be a first polyol component having an average of two hydroxyl groups (hereinafter referred to as a diol component).

[0059] That is, the first polyurethane resin does not contain a crosslinked structure. Therefore, the first polyol component does not contain a polyol component having an average number of hydroxyl groups exceeding 2. Preferably, the first polyol component is made of a diol component.

[0060] The diol component includes, for example, low molecular weight diols and macrodiols.

[0061] The low-molecular-weight diol is an organic compound having two hydroxyl groups in one molecule and a relatively low molecular weight. The molecular weight of the low-molecular-weight diol is, for example, 40 or more, and, for example, less than 400, preferably less than 300.

[0062] Examples of low-molecular-weight diols include dihydric alcohols. Examples of dihydric alcohols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, and dipropylene glycol. Examples of low-molecular-weight diols include polymers (number-average molecular weight less than 400) obtained by addition polymerization of alkylene (C2-3) oxide with dihydric alcohols. These can be used alone or in combination of two or more. Examples of low-molecular-weight diols include dihydric alcohols, and more preferably 1,4-butanediol.

[0063] The macrodiol has two hydroxyl groups in the molecule and is a relatively high molecular weight organic compound. The number average molecular weight of the macrodiol is, for example, 400 or more, preferably 500 or more. The number average molecular weight of the macrodiol is, for example, 5000 or less, preferably 3000 or less, more preferably less than 2500, even more preferably 2200 or less, and particularly preferably 1750 or less. If the number average molecular weight of the macrodiol is below the above upper limit, the transparency of the fiber-reinforced resin sheet is improved, and the visibility of the fiber design can be improved.

[0064] Examples of macrodiols include polyether diols, polyester diols, polycarbonate diols, polyurethane diols, epoxy diols, vegetable oil diols, polyolefin diols, acrylic diols, and vinyl monomer-modified diols. These can be used alone or in combination of two or more.

[0065] The macrodiol preferably includes polyether diol, polyester diol, and polycarbonate diol.

[0066] Examples of polyether diols include polyoxyalkylene diols, such as polyoxyalkylene (C2-3) glycols and polytetramethylene ether glycols.

[0067] Examples of polyester diols include condensation polyester diols and ring-opening polyester diols. Examples of condensation polyester diols include adipate polyester diols and phthalate polyester diols. Examples of ring-opening polyester polyols include lactone polyester diols.

[0068] Examples of polycarbonate diols include ring-opening polymers of ethylene carbonate using the above-mentioned dihydric polyols as initiators.

[0069] As the macrodiol, from the viewpoint of heat resistance, polyether diol is particularly preferred, and polytetramethylene ether glycol is more preferred.

[0070] The first polyol component can be used alone or in combination of two or more types. As the first polyol component, a combination of a low molecular weight diol and a macro diol is preferably used. That is, the first raw material component contains a low molecular weight diol and a macro diol.

[0071] When a low-molecular-weight diol and a macrodiol are used in combination, their ratio is appropriately set depending on the purpose and application. Preferably, the ratio of the low-molecular-weight diol and the macrodiol used in combination is adjusted so that the hard segment concentration of the first polyurethane resin falls within the range described below. Also, preferably, the ratio of the low-molecular-weight diol and the macrodiol used in combination is adjusted so that the urethane group concentration of the first polyurethane resin falls within the range described below.

[0072] For example, the amount of the low molecular weight diol is 10 parts by mass or more, preferably 30 parts by mass or more, more preferably 50 parts by mass or more, relative to 100 parts by mass of the macrodiol, and 500 parts by mass or less, preferably 300 parts by mass or less, more preferably 150 parts by mass or less, relative to 100 parts by mass of the macrodiol.

[0073] Furthermore, the macrodiol accounts for, for example, 10 mol% or more, preferably 20 mol% or more, based on the total amount of the macrodiol and the low molecular weight diol. Furthermore, the macrodiol accounts for, for example, 80 mol% or less, preferably 65 mol% or less, based on the total amount of the macrodiol and the low molecular weight diol. Furthermore, the low molecular weight diol accounts for, for example, 20 mol% or more, preferably 35 mol% or more, based on the total amount of the macrodiol and the low molecular weight diol. Furthermore, the low molecular weight diol accounts for, for example, 90 mol% or less, preferably 80 mol% or less, based on the total amount of the macrodiol and the low molecular weight diol.

[0074] When the ratio of the macrodiol to the low-molecular-weight diol is within the above range, the fiber-reinforced resin sheet has excellent heat resistance and weather resistance, and further has excellent flexibility and flex recovery.

[0075] The first polyurethane resin can be obtained by reacting a first polyisocyanate component (diisocyanate component) with a first polyol component (diol component). Examples of the reaction method include the one-shot method and the prepolymer method. The prepolymer method is preferably used.

[0076] In the prepolymer method, first, a diisocyanate component and a macrodiol are polymerized by a known polymerization method to synthesize an isocyanate group-terminated prepolymer (prepolymer synthesis step).

[0077] The blending ratio of the diisocyanate component and the macrodiol is adjusted so that the isocyanate groups of the diisocyanate component are in excess relative to the hydroxyl groups of the macrodiol. More specifically, the equivalent ratio of the isocyanate groups in the diisocyanate component to the hydroxyl groups in the macrodiol (isocyanate groups / hydroxyl groups) is, for example, 1.2 or more, preferably 1.5 or more. Furthermore, the equivalent ratio of the isocyanate groups in the diisocyanate component to the hydroxyl groups in the macrodiol (isocyanate groups / hydroxyl groups) is, for example, 10 or less, preferably 7 or less, more preferably 5 or less, and even more preferably 4.5 or less.

[0078] Polymerization methods include, for example, bulk polymerization and solution polymerization. In bulk polymerization, for example, a diisocyanate component and a macrodiol are reacted under a nitrogen stream. The reaction temperature is, for example, 50°C or higher. The reaction temperature is, for example, 250°C or lower, preferably 200°C or lower. The reaction time is, for example, 0.5 hours or higher, preferably 1 hour or higher. The reaction time is, for example, 15 hours or lower. In solution polymerization, a diisocyanate component and a macrodiol are reacted in the presence of a known organic solvent. The reaction temperature is, for example, 50°C or higher. The reaction temperature is, for example, 120°C or lower, preferably 100°C or lower. The reaction time is, for example, 1 minute or higher, preferably 5 minutes or higher. The reaction time is, for example, 15 hours or lower.

[0079] If necessary, a known urethanization catalyst such as an amine or an organometallic compound can be added. The amount of the urethanization catalyst added is appropriately determined depending on the purpose and application.

[0080] This produces a reaction mixture containing an isocyanate-terminated prepolymer. The isocyanate group concentration of the reaction mixture is, for example, 1% by mass or more, preferably 3% by mass or more, and more preferably 4% by mass or more. The isocyanate group concentration of the reaction mixture is, for example, 30% by mass or less, preferably 19% by mass or less, more preferably 16% by mass or less, even more preferably 15% by mass or less, and even more preferably 10% by mass or less. The isocyanate group concentration (isocyanate group content) can be determined by known methods such as titration with di-n-butylamine or FT-IR analysis.

[0081] The reaction mixture obtained by the above reaction may contain unreacted diisocyanate components (isocyanate monomers) in addition to the isocyanate-terminated prepolymer. If necessary, the unreacted diisocyanate components are removed from the reaction mixture by a known removal method. Examples of the removal method include distillation and extraction.

[0082] The first polyurethane resin is obtained by reacting the isocyanate group-terminated prepolymer with a chain extender (chain extension step).

[0083] The chain extender includes, for example, a low molecular weight diol, and preferably consists of a low molecular weight diol.

[0084] The blending ratio of the isocyanate-terminated prepolymer and the chain extender is appropriately set. For example, the equivalent ratio (isocyanate group / hydroxyl group) of the isocyanate groups in the isocyanate-terminated prepolymer to the hydroxyl groups in the chain extender (low molecular weight diol) is, for example, 0.75 or more, preferably 0.9 or more. Furthermore, the equivalent ratio (isocyanate group / hydroxyl group) of the isocyanate groups in the isocyanate-terminated prepolymer to the hydroxyl groups in the chain extender (low molecular weight diol) is, for example, 1.3 or less, preferably 1.2 or less.

[0085] In addition, bulk polymerization and / or solution polymerization is employed in the reaction between the isocyanate-terminated prepolymer and the chain extender (low-molecular-weight diol). The reaction temperature is, for example, room temperature or higher, preferably 50°C or higher. The reaction temperature is, for example, 200°C or lower, preferably 150°C or lower. The reaction time is, for example, 5 minutes or longer, preferably 1 hour or longer. The reaction time is, for example, 72 hours or shorter, preferably 48 hours or shorter. When mixing the isocyanate-terminated prepolymer and the chain extender, a urethane catalyst can be added at an appropriate ratio, if necessary.

[0086] This results in a first polyurethane resin containing a reaction product of the isocyanate group-terminated prepolymer and the chain extender.

[0087] The first polyurethane resin is a reaction product of a diisocyanate component and a diol component, and therefore does not have a urea bond or a crosslinked structure.

[0088] In other words, the first polyurethane resin is preferably a thermoplastic polyurethane resin.

[0089] The first polyurethane resin is heat-treated as needed. The heat treatment temperature is, for example, 50°C or higher, preferably 80°C or higher. The heat treatment temperature is, for example, 200°C or lower, preferably 150°C or lower. The heat treatment time is, for example, 30 minutes or longer, preferably 1 hour or longer. The heat treatment time is, for example, 10 days or shorter, preferably 5 days or shorter.

[0090] The first polyurethane resin may contain known additives. That is, the first polyurethane resin may be a resin composition. Examples of additives include antioxidants, heat stabilizers, UV absorbers, weather stabilizers, light stabilizers, antiblocking agents, release agents, pigments, dyes, lubricants, fillers, hydrolysis inhibitors, rust inhibitors, and bluing agents. The amount and timing of addition of the additives are appropriately determined depending on the purpose and application.

[0091] The first polyurethane resin is molded into a sheet or film by a known method, for example. Examples of molding methods include thermal compression molding, injection molding, and extrusion molding, with extrusion molding being preferred. In the extrusion molding method, for example, the first polyurethane resin is first pelletized by a known method. The pellets of the first polyurethane resin are then melted using a known extruder and extruded into a sheet or film. This produces a sheet or film of the first polyurethane resin.

[0092] The first polyurethane resin is cured as necessary. Preferably, a sheet or film of the first polyurethane resin is cured. The curing temperature is, for example, 10°C or higher, preferably 20°C or higher. The curing temperature is, for example, 50°C or lower, preferably 40°C or lower. The curing time is, for example, 1 hour or longer, preferably 10 hours or longer. The curing time is, for example, 20 days or shorter, preferably 10 days or shorter.

[0093] The hard segment concentration of the first polyurethane resin is, for example, 5% by mass or more, preferably 8% by mass or more, more preferably 11% by mass or more, and even more preferably 15% by mass or more. The hard segment concentration of the first polyurethane resin is, for example, 60% by mass or less, preferably 55% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less. When the hard segment concentration of the first polyurethane resin is within the above range, a fiber-reinforced resin sheet having excellent mechanical properties can be obtained.

[0094] The hard segment of the first polyurethane resin refers to a hard segment formed by the reaction of the first polyisocyanate component with the low-molecular-weight diol. The hard segment concentration can be calculated by a known method, for example, based on the blending ratio (charge) of each component.

[0095] More specifically, when a prepolymer method is used, the hard segment concentration can be calculated by the following formula based on the blending recipe (charge) of each component. [Chain extender (g) + (Chain extender (g) / Molecular weight of chain extender (g / mol)) × Average molecular weight of first polyisocyanate component (g / mol)] ÷ (First polyisocyanate component (g) + Total mass of first polyol component (g)) × 100

[0096] The urethane group concentration of the first polyurethane resin is, for example, 1.0 mmol / g or more, preferably 1.5 mmol / g or more, more preferably 1.7 mmol / g or more, and even more preferably 2.5 mmol / g or more. The urethane group concentration of the first polyurethane resin is, for example, 8.0 mmol / g or less, preferably 4.5 mmol / g or less, more preferably 3.4 mmol / g or less, and even more preferably 3.0 mmol / g or less. When the urethane group concentration of the first polyurethane resin is within the above range, a fiber-reinforced resin sheet having excellent mechanical properties can be obtained.

[0097] The urethane group concentration can be calculated by a known method based on the compounding recipe (charge) of each component.

[0098] The calorific value of the recrystallization peak of the urethane group of the first polyurethane resin is, for example, 1 (mJ / mg) or more, preferably 3.5 (mJ / mg) or more, and, for example, 40 (mJ / mg) or less, preferably 30 (mJ / mg) or less.

[0099] The calorific value of the recrystallization peak of the urethane group of the first polyurethane resin is measured by differential scanning calorimetry (DSC measurement) in accordance with the examples described later.

[0100] More specifically, in differential scanning calorimetry (DSC), among the peaks that appear during cooling after heating to 270°C, an exothermic peak (recrystallization peak) between 50°C and 180°C is taken as the recrystallization peak of the urethane group. The width of this peak is taken as the exothermic range (°C). Furthermore, the heat quantity (enthalpy change) (mJ / mg) at the recrystallization peak is taken as the exothermic value of the recrystallization peak.

[0101] The first polyurethane resin preferably satisfies the following formula (1). Formula (1) below represents the crystallinity of the first polyurethane resin. The higher the value of formula (1) below, the higher the crystallinity and the more likely the resin is to wrinkle when bent, resulting in relatively low flex recovery. The lower the value of formula (1) below, the lower the crystallinity and the less likely the resin is to wrinkle when bent, resulting in relatively high flex recovery.

[0102] Equation (1): 0< [heat release amount of urethane group recrystallization peak (mJ / mg) ÷ heat release section (℃)] <0.85

[0103] The value of the above formula (1) of the first polyurethane resin exceeds 0, for example, and is preferably 0.01 or more, and more preferably 0.02 or more. The value of the above formula (1) of the first polyurethane resin is, for example, 0.85 or less, preferably 0.45 or less, and more preferably 0.20 or less. When the value of the above formula (1) is within the above range, a reinforced fiber resin sheet having excellent flex recovery can be obtained.

[0104] When the first polyurethane resin is a sheet and / or film, the thickness of the first polyurethane resin is, for example, 50 μm or more, or preferably 100 μm or more, and for example, 1000 μm or less, or preferably 500 μm or less.

[0105] (B) Second polyurethane resin The second polyurethane resin is a polyurethane resin containing a urea bond and / or a crosslinked structure.

[0106] The second polyurethane resin includes, for example, a reaction product of a second raw material component, which includes, for example, a second polyisocyanate component and a second active hydrogen group-containing component.

[0107] The second polyisocyanate component is a component containing one or more isocyanate groups in one molecule. The second active hydrogen group-containing component is a component containing one or more active hydrogen groups in one molecule.

[0108] Examples of active hydrogen groups include hydroxyl groups and amino groups. The second active hydrogen group-containing component containing a hydroxyl group is referred to as the second polyol component. The second active hydrogen group-containing component containing an amino group is referred to as the second amine component.

[0109] More specifically, the second polyurethane resin may be a polyurethane resin containing at least a urea bond (a urea-containing polyurethane resin) or a polyurethane resin containing at least a crosslinked structure (a crosslink-containing polyurethane resin).

[0110] The urea-containing polyurethane resin and the crosslinked polyurethane resin will be described in detail below.

[0111] (B-1) Urea-containing polyurethane resin The urea-containing polyurethane resin can be obtained by reacting a second polyisocyanate component with a second active hydrogen group-containing component.

[0112] In the urea-containing polyurethane resin, the second active hydrogen group-containing component contains a second amine component. Preferably, the second active hydrogen group-containing component contains a second polyol component and a second amine component.

[0113] The form of the urea-containing polyurethane resin is not particularly limited, but the urea-containing polyurethane resin is preferably contained in a polyurethane dispersion.

[0114] More specifically, the urea-containing polyurethane resin is preferably applied to a first polyurethane resin (substrate) as described below. Therefore, the urea-containing polyurethane resin is preferably produced as a coating composition. From this perspective, the urea-containing polyurethane resin is preferably contained in a polyurethane dispersion (PUD).

[0115] The polyurethane dispersion (PUD) containing the urea-containing polyurethane resin will be described in detail below.

[0116] The polyurethane dispersion containing the urea-containing polyurethane resin can be obtained, for example, by the following method.

[0117] In this method, first, an isocyanate-terminated prepolymer is synthesized. The isocyanate-terminated prepolymer is a polyurethane prepolymer having two or more free isocyanate groups at the molecular terminals.

[0118] The isocyanate group-terminated prepolymer can be obtained, for example, by reacting a second polyisocyanate component with a second polyol component.

[0119] Examples of the second polyisocyanate component include alicyclic polyisocyanates, linear aliphatic polyisocyanates, aromatic polyisocyanates, and aromatic aliphatic polyisocyanates.

[0120] Examples of alicyclic polyisocyanates include alicyclic polyisocyanate monomers and alicyclic polyisocyanate derivatives. Examples of alicyclic polyisocyanate monomers include the above-mentioned alicyclic diisocyanates. Examples of alicyclic polyisocyanate derivatives include modified products of alicyclic polyisocyanate monomers. Examples of modified products include uretdione-modified products, isocyanurate-modified products, allophanate-modified products, polyol-modified products, biuret-modified products, urea-modified products, oxadiazinetrione-modified products, and carbodiimide-modified products. These can be used alone or in combination of two or more types.

[0121] Examples of the chain aliphatic polyisocyanate include chain aliphatic polyisocyanate monomers and chain aliphatic polyisocyanate derivatives. Examples of the chain aliphatic polyisocyanate monomers include the chain aliphatic diisocyanates described above. Examples of the chain aliphatic polyisocyanate derivatives include the modified chain aliphatic polyisocyanate monomers described above.

[0122] Examples of aromatic polyisocyanates include aromatic polyisocyanate monomers and aromatic polyisocyanate derivatives. Examples of aromatic polyisocyanate monomers include the above-mentioned aromatic diisocyanates. Examples of aromatic polyisocyanate derivatives include the above-mentioned modified products of aromatic polyisocyanate monomers.

[0123] Examples of the araliphatic polyisocyanate include araliphatic polyisocyanate monomers and araliphatic polyisocyanate derivatives. Examples of the araliphatic polyisocyanate monomers include the above-mentioned araliphatic diisocyanates. Examples of the araliphatic polyisocyanate derivatives include the above-mentioned modified products of the araliphatic polyisocyanate monomers.

[0124] These can be used alone or in combination of two or more. As the second polyisocyanate component, preferably, an alicyclic polyisocyanate monomer is used, more preferably, an alicyclic diisocyanate is used, further preferably, 1,3-bis(isocyanatomethyl)cyclohexane and isophorone diisocyanate are used, and particularly preferably, isophorone diisocyanate is used.

[0125] The average number of isocyanate groups in the second polyisocyanate component is, for example, 2 or more. Furthermore, the average number of isocyanate groups in the second polyisocyanate component is, for example, 6 or less, preferably 4 or less, more preferably 3 or less, and even more preferably 2 or less. That is, the average number of isocyanate groups in the second polyisocyanate component is particularly preferably 2.

[0126] The second polyol component includes, for example, a hydrophilic group-containing polyol.

[0127] The hydrophilic group-containing polyol is a polyol containing a hydrophilic group. Examples of the hydrophilic group include a nonionic group and an ionic group. More specifically, examples of the hydrophilic group-containing polyol include a nonionic group-containing polyol and an ionic group-containing polyol.

[0128] The nonionic group-containing polyol is a compound having one or more nonionic groups and two or more hydroxyl groups. Examples of the nonionic group include a polyoxyethylene group. Examples of the nonionic group-containing polyol include polyoxyethylene glycol, one-end-blocked polyoxyethylene glycol, and polyoxyethylene side chain-containing polyol.

[0129] Examples of ionic group-containing polyols include anionic group-containing polyols and cationic group-containing polyols. Anionic group-containing polyols are compounds having both one or more anionic groups and two or more hydroxyl groups. Examples of anionic groups include carboxy groups (carboxylic acid groups) and sulfo groups (sulfonic acid groups). Cationic group-containing polyols are compounds having both one or more cationic groups and two or more hydroxyl groups. Examples of cationic groups include quaternary ammonium groups.

[0130] These hydrophilic group-containing polyols can be used alone or in combination of two or more.Preferably, the hydrophilic group-containing polyol is an anionic group-containing polyol.

[0131] The anionic group-containing polyol is preferably a carboxyl group-containing polyol. Examples of the carboxyl group-containing polyol include polyhydroxyalkanoic acid. Examples of the polyhydroxyalkanoic acid include 2,2-dimethylolacetic acid, 2,2-dimethylollactic acid, 2,2-dimethylolpropionic acid (DMPA), 2,2-dimethylolbutanoic acid, 2,2-dimethylolbutyric acid, and 2,2-dimethylolvaleric acid. These carboxyl group-containing polyols can be used alone or in combination of two or more. Examples of the carboxyl group-containing polyol include polyhydroxyalkanoic acid, more preferably 2,2-dimethylolpropionic acid (DMPA).

[0132] The second polyol component preferably contains other polyols. The other polyols are polyols other than hydrophilic group-containing polyols. Examples of the other polyols include low-molecular-weight polyols and macropolyols.

[0133] The low-molecular-weight polyol is an organic compound having two or more hydroxyl groups in the molecule and a relatively low molecular weight. The molecular weight of the low-molecular-weight polyol is, for example, 40 or more, and, for example, less than 400, preferably less than 300.

[0134] Examples of low-molecular-weight polyols include dihydric alcohols, trihydric alcohols, and tetrahydric or higher alcohols. Examples of dihydric alcohols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, and dipropylene glycol. Examples of trihydric alcohols include glycerin and trimethylolpropane. Examples of tetrahydric or higher alcohols include pentaerythritol and diglycerin. Examples of low-molecular-weight polyols include polymers obtained by addition polymerization of alkylene (C2-3) oxide with dihydric to tetrahydric alcohols to obtain a number-average molecular weight of less than 400.

[0135] These low molecular weight polyols can be used alone or in combination of two or more. Preferred low molecular weight polyols include dihydric alcohols and trihydric alcohols, and more preferably dihydric alcohols.

[0136] The macropolyol has two or more hydroxyl groups in the molecule and is a relatively high molecular weight organic compound. The number average molecular weight of the macropolyol is, for example, 400 or more, preferably 500 or more. The number average molecular weight of the macropolyol is, for example, 5000 or less, preferably 3000 or less, more preferably less than 2500, even more preferably 2200 or less, and particularly preferably 1750 or less. If the number average molecular weight of the macropolyol is below the above upper limit, the transparency of the fiber reinforced resin sheet is improved, and the visibility of the fiber design can be improved. The average number of functional groups (average number of hydroxyl groups) of the macropolyol is, for example, 2 or more. The average number of functional groups (average number of hydroxyl groups) of the macropolyol is, for example, 6 or less, preferably 4 or less, more preferably 3 or less.

[0137] Examples of macropolyols include polyether polyols, polyester polyols, polycarbonate polyols, polyurethane polyols, epoxy polyols, vegetable oil polyols, polyolefin polyols, acrylic polyols, and vinyl monomer-modified polyols. Preferred examples of macropolyols include polyether polyols, polyester polyols, and polycarbonate polyols.

[0138] Examples of polyether polyols include polyoxyalkylene polyols, such as polyoxyalkylene (C2-3) polyols and polytetramethylene ether polyols.

[0139] Examples of polyester polyols include condensation polyester polyols and ring-opening polyester polyols. Examples of condensation polyester polyols include adipate polyester polyols and phthalate polyester polyols. Examples of ring-opening polyester polyols include lactone polyester polyols.

[0140] Examples of polycarbonate polyols include ring-opening polymers of ethylene carbonate using the above-mentioned low-molecular-weight polyols as initiators.

[0141] These macropolyols can be used alone or in combination of two or more. Preferred examples of the macropolyol include polyether polyols, polyester polyols, and polycarbonate polyols, more preferred examples include polyester polyols and polycarbonate polyols, even more preferred examples include polyester polyols, and particularly preferred examples include condensation polyester polyols.

[0142] The number average molecular weight (polystyrene equivalent molecular weight) of the macropolyol is, for example, 400 or more, preferably 800 or more, more preferably 1000 or more, and even more preferably 1500 or more. The number average molecular weight (polystyrene equivalent molecular weight) of the macropolyol is, for example, 5000 or less, preferably 3000 or less, and more preferably 2000 or less.

[0143] The average number of hydroxyl groups in the macropolyol is, for example, 2 or more. The average number of hydroxyl groups in the macropolyol is, for example, 6 or less, preferably 4 or less, more preferably 3 or less, and even more preferably 2 or less. That is, the average number of hydroxyl groups in the macropolyol is particularly preferably 2.

[0144] The other polyols can be used alone or in combination of two or more thereof. As the other polyols, a combination of a low molecular weight polyol and a macro polyol is preferably used.

[0145] The content of the low molecular weight polyol relative to the total amount of other polyols (total amount of low molecular weight polyols and macropolyols) is, for example, 1% by mass or more, preferably 3% by mass or more. The content of the low molecular weight polyol relative to the total amount of other polyols (total amount of low molecular weight polyols and macropolyols) is, for example, 20% by mass or less, preferably 15% by mass or less.

[0146] The content of the macropolyol relative to the total amount of other polyols (total amount of low molecular weight polyols and macropolyols) is, for example, 80% by mass or more, preferably 85% by mass or more. The content of the low molecular weight polyol relative to the total amount of other polyols (total amount of low molecular weight polyols and macropolyols) is, for example, 99% by mass or less, preferably 97% by mass or less.

[0147] The content of the hydrophilic group-containing polyol relative to the total amount of the second polyol component (total amount of the hydrophilic group-containing polyol, low-molecular-weight polyol, and macropolyol) is, for example, 3% by mass or more, preferably 5% by mass or more. The content of the hydrophilic group-containing polyol relative to the total amount of the second polyol component (total amount of the hydrophilic group-containing polyol, low-molecular-weight polyol, and macropolyol) is, for example, 20% by mass or less, preferably 13% by mass or less.

[0148] The content of the other polyols relative to the total amount of the second polyol component (total amount of the hydrophilic group-containing polyol, low-molecular-weight polyol, and macropolyol) is, for example, 80% by mass or more, preferably 87% by mass or more. The content of the hydrophilic group-containing polyol relative to the total amount of the second polyol component (total amount of the hydrophilic group-containing polyol, low-molecular-weight polyol, and macropolyol) is 97% by mass or less, preferably 95% by mass or less.

[0149] The isocyanate-terminated prepolymer is obtained by reacting a second polyisocyanate component with a second polyol component at a predetermined equivalent ratio. In synthesizing the isocyanate-terminated prepolymer, the equivalent ratio refers to the equivalent ratio of isocyanate groups to active hydrogen groups (hydroxyl groups) (isocyanate groups / active hydrogen groups). The equivalent ratio (isocyanate groups / active hydrogen groups) is, for example, greater than 1, preferably 1.1 or greater. The equivalent ratio (isocyanate groups / active hydrogen groups) is, for example, 20 or less, preferably 10 or less.

[0150] Furthermore, known polymerization methods are employed in the synthesis of the isocyanate group-terminated prepolymer. Examples of the polymerization method include bulk polymerization and solution polymerization. From the viewpoint of adjusting the reactivity, solution polymerization is preferably employed as the polymerization method. In bulk polymerization, for example, the above components are blended and reacted under a nitrogen atmosphere. The reaction temperature is, for example, 75 to 85°C. The reaction time is, for example, 1 to 20 hours. In solution polymerization, for example, the above components are blended and reacted in an organic solvent under a nitrogen atmosphere. The reaction temperature is, for example, 20 to 80°C. The reaction time is, for example, 1 to 20 hours. Examples of the organic solvent include solvents inactive to isocyanate groups.

[0151] In addition, a catalyst can be added to the polymerization as needed. Examples of the catalyst include amine catalysts and organometallic catalysts. These catalysts can be used alone or in combination of two or more. The amount of catalyst added is appropriately determined depending on the purpose and application.

[0152] In this method, the polymerization is terminated, for example, when the isocyanate group concentration in the reaction product reaches the range described below. In this method, the unreacted polyisocyanate component can be removed by a known removal method. Examples of the removal method include distillation and extraction. This results in an isocyanate-terminated prepolymer.

[0153] The isocyanate group concentration of the isocyanate group-terminated prepolymer is, for example, 4% by mass or more, preferably 5% by mass or more, more preferably 6% by mass or more, and for example, 25% by mass or less, preferably 20% by mass or less, more preferably 17% by mass or less, and even more preferably 15% by mass or less.

[0154] The average functionality of the isocyanate groups is, for example, 1.5 or more, preferably 1.9 or more, more preferably 2.0 or more, and for example, 3.0 or less, preferably 2.5 or less.

[0155] Furthermore, when the isocyanate-terminated prepolymer contains an anionic group, for example, a neutralizing agent is added to the isocyanate-terminated prepolymer to neutralize it and form a salt of the anionic group. Examples of the neutralizing agent include conventional bases. Specific examples of the base include organic bases and inorganic bases.

[0156] Examples of organic bases include tertiary amines and secondary amines. Examples of tertiary amines include trialkylamines and alkanolamines. Examples of trialkylamines include trialkylamines having 1 to 4 carbon atoms. Examples of such trialkylamines include trimethylamine and triethylamine (TEA). Examples of alkanolamines include dimethylethanolamine, methyldiethanolamine, triethanolamine, and triisopropanolamine (TIPA). Examples of secondary amines include heterocyclic amines. Examples of heterocyclic amines include morpholine. These organic bases can be used alone or in combination of two or more.

[0157] Examples of inorganic bases include ammonia, alkali metal hydroxides, alkaline earth metal hydroxides, and alkali metal carbonates. Examples of alkali metal hydroxides include lithium hydroxide, sodium hydroxide, and potassium hydroxide. Examples of alkaline earth metal hydroxides include magnesium hydroxide and calcium hydroxide. Examples of alkali metal carbonates include sodium carbonate and potassium carbonate. These inorganic bases can be used alone or in combination.

[0158] These neutralizing agents can be used alone or in combination of two or more. As the neutralizing agent, preferably, an organic base is used, more preferably, a tertiary amine is used, further preferably, a trialkylamine is used, and particularly preferably, triethylamine is used.

[0159] The amount of the neutralizing agent added is, for example, 0.4 equivalents or more, preferably 0.6 equivalents or more, relative to 1 equivalent of the anionic group, and is, for example, 1.2 equivalents or less, preferably 1.0 equivalent or less, relative to 1 equivalent of the anionic group.

[0160] Next, in this method, the isocyanate group-terminated prepolymer (first reaction product) is reacted with a chain extender to obtain a second polyurethane resin (second reaction product).

[0161] For example, a polyurethane dispersion can be obtained by reacting an isocyanate-terminated prepolymer with a chain extender in water.

[0162] The chain extender is an organic compound that has multiple active hydrogen groups and that causes a chain extension reaction of the isocyanate-terminated prepolymer. Examples of the chain extender include secondary amine components.

[0163] Secondary amine components include, for example, polyamines and amino alcohols.

[0164] Examples of polyamines include aromatic polyamines, araliphatic polyamines, alicyclic polyamines, aliphatic polyamines, and polyoxyethylene group-containing polyamines. Examples of aromatic polyamines include 4,4'-diphenylmethanediamine and tolylenediamine. Examples of araliphatic polyamines include 1,3-xylylenediamine and 1,4-xylylenediamine. Examples of alicyclic polyamines include ethylenediamine, 3-aminomethyl-3,5,5-trimethylcyclohexylamine (also known as isophoronediamine), 4,4'-dicyclohexylmethanediamine, 2,5-bis(aminomethyl)bicyclo[2.2.1]heptane, 2,6-bis(aminomethyl)bicyclo[2.2.1]heptane, 1,4-cyclohexanediamine, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, bis-(4-aminocyclohexyl)methane, diaminocyclohexane, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro[5,5]undecane, 1,3-bis(aminomethyl)cyclohexane, and 1,4-bis(aminomethyl)cyclohexane. Examples of aliphatic polyamines include propylene diamine, 1,3-propane diamine, 1,4-butane diamine, 1,5-pentane diamine, 1,6-hexamethylene diamine, hydrazine (HYD), hydrazine hydrate, diethylene triamine, triethylene tetramine, tetraethylene pentamine, 1,2-diaminoethane, 1,2-diaminopropane, and 1,3-diaminopentane. Examples of polyoxyethylene group-containing polyamines include polyoxyalkylene ether diamines. Examples of polyoxyalkylene ether diamines include polyoxyethylene ether diamines. More specific examples include PEG#1000 Diamine (manufactured by Nippon Oil & Fats Co.), Jeffamine ED-2003 (manufactured by Huntsman), Jeffamine EDR-148 (manufactured by Huntsman), and Jeffamine XTJ-512 (manufactured by Huntsman).

[0165] Examples of amino alcohols include N-(β-aminoethyl)ethanolamine and N-(β-aminoethyl)isopropanolamine.

[0166] The amine component also includes an alkoxysilyl compound having a primary amino group, such as γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and N-phenyl-γ-aminopropyltrimethoxysilane.

[0167] The amine component also includes an alkoxysilyl compound having a primary amino group and a secondary amino group. Examples of the alkoxysilyl compound having a primary amino group and a secondary amino group include N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, and N-2-(aminoethyl)-3-aminopropylmethyldiethoxysilane.

[0168] The secondary amine component can be used alone or in combination of two or more kinds. As the secondary amine component, preferably, polyamine is used, more preferably, aliphatic polyamine is used, and further preferably, hydrazine is used.

[0169] More specifically, the second amine component preferably includes at least a polyamine. The second amine component may consist of a polyamine.

[0170] The second amine component preferably contains a polyamine and an alkoxysilyl compound having a primary amino group and a secondary amino group.

[0171] When the second amine component contains a polyamine and an alkoxysilyl compound having a primary amino group and a secondary amino group, the second amine component can form a urea bond and a crosslinked structure in a chain extension reaction. That is, the second polyurethane resin contains a urea bond and a crosslinked structure. Such a second polyurethane resin can provide particularly excellent sewing durability.

[0172] In such a case, the proportion of the alkoxysilyl compound having a primary amino group and a secondary amino group relative to the total amount of the secondary amine component is, for example, 50% by mass or more, preferably 60% by mass or more, and the proportion of the alkoxysilyl compound having a primary amino group and a secondary amino group relative to the total amount of the secondary amine component is, for example, 90% by mass or less, preferably 80% by mass or less.

[0173] The proportion of the polyamine relative to the total amount of the secondary amine components is, for example, 10% by mass or more, or preferably 20% by mass or more, and for example, 50% by mass or less, or preferably 40% by mass or less, relative to the total amount of the secondary amine components.

[0174] In the chain extension reaction, for example, an isocyanate-terminated prepolymer and a chain extender (secondary amine component) are reacted in water. More specifically, for example, the isocyanate-terminated prepolymer is first dispersed in water. Next, the chain extender is added to the aqueous dispersion of the isocyanate-terminated prepolymer, and the isocyanate-terminated prepolymer is chain-extended by the chain extender.

[0175] The method for dispersing the isocyanate-terminated prepolymer in water is not particularly limited. For example, the isocyanate-terminated prepolymer is added to the water (aqueous dispersion) while stirring the water (aqueous dispersion). In this case, the amount of water is 100 to 1,000 parts by mass per 100 parts by mass of the isocyanate-terminated prepolymer.

[0176] If necessary, a part of the chain extender may be mixed in advance with water (aqueous dispersion liquid) to disperse the isocyanate group-terminated prepolymer in water and also to extend the chain of the isocyanate group-terminated prepolymer.

[0177] Thereafter, the chain extender is added dropwise to the water in which the isocyanate-terminated prepolymer is dispersed while stirring the water. If a portion of the chain extender is mixed in advance with the water (aqueous dispersion), the remaining portion of the chain extender is added dropwise to the water in which the isocyanate-terminated prepolymer is dispersed.

[0178] The chain extender may be added dropwise all at once or in portions. The equivalent ratio of the active hydrogen groups of the chain extender to the isocyanate groups of the isocyanate group-terminated prepolymer (active hydrogen groups / isocyanate groups) is, for example, 0.6 to 1.2. The chain extension reaction is completed, for example, at room temperature. The time required for the reaction to be completed is, for example, 0.1 to 10 hours.

[0179] This results in the second polyurethane resin (urea-containing polyurethane resin) being obtained in water, that is, a polyurethane dispersion (PUD) containing the second polyurethane resin (urea-containing polyurethane resin) is obtained.

[0180] In this method, the organic solvent and / or water can be removed after the reaction is complete to adjust the solids concentration. In this method, water can be added after the reaction is complete to adjust the solids concentration. In this method, a solvent can be added to adjust the solids concentration. Examples of solvents include water, methanol, ethanol, propanol, isopropanol, acetone, methyl ethyl ketone, ethyl acetate, tetrahydrofuran, and acetonitrile. These solvents can be used alone or in combination of two or more.

[0181] The solid content concentration of the polyurethane dispersion is, for example, 10% by mass or more, preferably 15% by mass or more, and more preferably 20% by mass or more. The solid content concentration of the polyurethane dispersion is, for example, 60% by mass or less, preferably 50% by mass or less, and more preferably 40% by mass or less. The solid content concentration is appropriately adjusted by a known method.

[0182] The polyurethane dispersion may also contain additives. Examples of additives include fillers, silane coupling agents, alkoxysilane compounds, thickeners, antioxidants, heat stabilizers, UV absorbers, plasticizers, antistatic agents, lubricants, antiblocking agents, surfactants, dispersion stabilizers, colorants, pigments, dyes, colloidal silica, inorganic particles, inorganic oxide particles, layered inorganic compounds, leveling agents, crystal nucleating agents, and crosslinking agents. These additives may be used alone or in combination of two or more.

[0183] In the above method, the chain extender contains a secondary amine component. The secondary amine component forms a urea bond by reacting with the isocyanate-terminated prepolymer. Therefore, the second polyurethane resin contains a urea bond. This second polyurethane resin can provide excellent sewing durability.

[0184] The chain extender may also contain an alkoxysilyl compound having a primary amino group and a secondary amino group. The alkoxysilyl compound having a primary amino group and a secondary amino group forms a crosslinked structure by self-crosslinking. Therefore, the second polyurethane resin may contain a crosslinked structure. This second polyurethane resin can provide particularly excellent sewing durability.

[0185] (B-2) Crosslinked polyurethane resin The crosslink-containing polyurethane resin is a polyurethane resin containing a chemical crosslink structure in the molecule, and is formed, for example, as a cured product of a polyurethane adhesive.

[0186] In other words, the polyurethane adhesive forms a cross-linked polyurethane resin through a curing reaction, i.e., the polyurethane adhesive is a precursor of the cross-linked polyurethane resin.

[0187] Examples of polyurethane adhesives include one-component curing polyurethane adhesives (moisture-curing polyurethane adhesives) and two-component curing polyurethane adhesives, which can be used alone or in combination of two or more types.

[0188] As the polyurethane adhesive, preferably, a one-component curing polyurethane resin is used.

[0189] The isocyanate group-terminated prepolymer can be obtained, for example, by reacting a second polyisocyanate component with a second polyol component.

[0190] Examples of the second polyisocyanate component include the above-mentioned alicyclic polyisocyanates, the above-mentioned chain aliphatic polyisocyanates, the above-mentioned aromatic polyisocyanates, and the above-mentioned araliphatic polyisocyanates. These can be used alone or in combination of two or more.

[0191] Examples of the second polyol component include the low molecular weight polyols and macro polyols described above. These can be used alone or in combination of two or more.

[0192] In the crosslink-containing polyurethane resin, the average number of isocyanate groups in the second polyisocyanate component and / or the average number of hydroxyl groups in the second polyol component exceeds two.

[0193] If the average number of isocyanate groups in the second polyisocyanate component and / or the average number of hydroxyl groups in the second polyol component exceeds 2, a chemical crosslinked structure is formed, and a crosslinked polyurethane resin is obtained.

[0194] Preferably, in the crosslink-containing polyurethane resin, the average number of isocyanate groups in the second polyisocyanate component exceeds two.

[0195] More specifically, the average number of isocyanate groups in the second polyisocyanate component of the crosslink-containing polyurethane resin is preferably more than 2, more preferably 3 or more. Also, the average number of isocyanate groups in the second polyisocyanate component of the crosslink-containing polyurethane resin is, for example, 6 or less, preferably 4 or less.

[0196] In such a case, the average number of hydroxyl groups in the second polyol component of the crosslink-containing polyurethane resin does not need to exceed 2. The average number of hydroxyl groups in the second polyol component of the crosslink-containing polyurethane resin is, for example, 2 or more and, for example, 6 or less.

[0197] The isocyanate-terminated prepolymer is obtained by reacting a second polyisocyanate component with a second polyol component at a predetermined equivalent ratio. In synthesizing the isocyanate-terminated prepolymer, the equivalent ratio refers to the equivalent ratio of isocyanate groups to active hydrogen groups (hydroxyl groups) (isocyanate groups / active hydrogen groups). The equivalent ratio (isocyanate groups / active hydrogen groups) is, for example, greater than 1, preferably 1.1 or greater. The equivalent ratio (isocyanate groups / active hydrogen groups) is, for example, 20 or less, preferably 10 or less.

[0198] In addition, known polymerization methods are used to synthesize the isocyanate-terminated prepolymer. Examples of the polymerization method include the bulk polymerization and the solution polymerization. The reaction conditions between the second polyisocyanate component and the second polyol component are appropriately set as needed.

[0199] In addition, a catalyst can be added to the polymerization as needed. Examples of the catalyst include amine catalysts and organometallic catalysts. These catalysts can be used alone or in combination of two or more. The amount of catalyst added is appropriately determined depending on the purpose and application.

[0200] In this method, the polymerization is terminated, for example, when the isocyanate group concentration in the reaction product reaches the range described below. In this method, the unreacted polyisocyanate component can be removed by a known removal method. Examples of the removal method include distillation and extraction. This results in an isocyanate-terminated prepolymer.

[0201] One-component curing polyurethane adhesives (moisture-curing polyurethane adhesives) can also contain additives as optional components. Examples of additives include phosphoric acid, phosphoric acid derivatives, silane coupling agents, antifoaming agents, epoxy resins, catalysts, coating property improvers, leveling agents, antioxidants, ultraviolet absorbers, plasticizers, surfactants, pigments, fillers, organic fine particles, inorganic fine particles, and antifungal agents. The blending ratio of the additives is determined appropriately depending on the purpose and application.

[0202] Furthermore, the one-component curing polyurethane adhesive (moisture-curing polyurethane adhesive) may contain a known organic solvent as an optional component. That is, the moisture-curing adhesive may be a solvent-based adhesive. The blending ratio of the organic solvent is appropriately set depending on the purpose and application.

[0203] Furthermore, the one-component curing polyurethane adhesive (moisture-curing polyurethane adhesive) does not have to contain an organic solvent, that is, the moisture-curing adhesive may be a solvent-free adhesive.

[0204] In order to suppress expansion of the first polyurethane resin when the one-component curing polyurethane adhesive is applied to the first polyurethane resin, the one-component curing polyurethane adhesive (moisture-curing polyurethane adhesive) is preferably a solvent-free adhesive.

[0205] Then, such a one-component curing polyurethane adhesive (moisture-curing polyurethane adhesive) is moisture-cured to form a second polyurethane resin (crosslink-containing polyurethane resin).

[0206] More specifically, the isocyanate-terminated prepolymer contained in the one-component curing polyurethane adhesive (moisture-curing polyurethane adhesive) reacts with moisture. Examples of moisture include atmospheric water and amine vapor. This reaction causes the one-component curing polyurethane adhesive (moisture-curing polyurethane adhesive) to cure while forming urea bonds and crosslinked structures.

[0207] That is, the second polyurethane resin (crosslink-containing polyurethane resin) is obtained as a cured product of the one-component curing polyurethane adhesive (moisture-curing polyurethane adhesive).

[0208] More specifically, the cured product of the one-component curing polyurethane adhesive (moisture-curing polyurethane adhesive) contains a crosslinked structure. Furthermore, the cured product of the one-component curing polyurethane adhesive (moisture-curing polyurethane adhesive) contains a urea bond. This second polyurethane resin can provide particularly excellent sewing durability.

[0209] (C) Other resins The resin may contain other resins. The other resins are resins other than the first polyurethane resin and the second polyurethane resin. Examples of other resins include polyolefin resins (e.g., polyethylene, polypropylene, polybutene, and poly(4-methyl-1-pentene)), polyamide resins, polyester resins, polystyrene resins, thermoplastic polyimide resins, polyamideimide resins, polycarbonate resins, polyphenylene ether resins, polyphenylene sulfide resins, polyacetal resins, acrylic resins, polyetherimide resins, polysulfone resins, polyetherketone resins, polyetheretherketone resins, polyarylate resins, polyethernitrile resins, vinyl chloride resins, acrylonitrile-butadiene-styrene (ABS) resins, and fluororesins. These may be used alone or in combination of two or more.

[0210] 2. Manufacturing method of fiber reinforced resin sheet The fiber-reinforced resin sheet is formed by impregnating a fiber assembly containing reinforcing fibers with a first polyurethane resin and a second polyurethane resin. Such a fiber-reinforced resin sheet has a first composite region containing the reinforcing fibers and a first resin component impregnated into the reinforcing fibers, and a second composite region containing the reinforcing fibers and a second resin component impregnated into the reinforcing fibers.

[0211] The "region" refers to a range that extends along the planar direction (direction perpendicular to the thickness direction) of the fiber-reinforced resin sheet and has a certain thickness. One region may be visually distinguishable from another region, or may be visually indistinguishable from the other region.

[0212] Hereinafter, a method for producing a fiber reinforced resin sheet by impregnating a fiber assembly containing reinforcing fibers with a resin will be described in detail with reference to FIG.

[0213] In this method, as shown in FIGS. 1A and 1B, the above-mentioned fiber assembly 2 containing reinforcing fibers and a polyurethane laminate sheet 3 are prepared (preparation step).

[0214] The polyurethane laminate sheet 3 is formed by laminating the first polyurethane resin and the second polyurethane resin.

[0215] The method for laminating the first polyurethane resin and the second polyurethane resin is not particularly limited, but examples thereof include the following methods.

[0216] In this method, for example, as shown in FIG. 1A, a film 31 made of a first polyurethane resin (hereinafter referred to as a first film) is prepared (film preparation step).

[0217] The first film 31 is a resin film. The first film 31 corresponds to a first resin component (described later). The first film 31 contains a first polyurethane resin as a main component.

[0218] The first film 31 may also contain the other resins described above. The content ratio of the other resins relative to the first resin component (described below) is adjusted so that the content ratio of the other resins relative to the first resin component (described below) falls within the range described below.

[0219] The first film 31 may also contain the second polyurethane resin. The content ratio of the second polyurethane resin relative to the first resin component (described later) is adjusted so that it falls within the range described later.

[0220] The first film 31 is preferably made of a first polyurethane resin.

[0221] There are no particular limitations on the method for preparing the first film 31. For example, the first polyurethane resin is molded into a film by a known molding method. Examples of the molding method include extrusion molding and injection molding, and preferably extrusion molding.

[0222] The thickness of the first film 31 is, for example, 1 μm or more, preferably 10 μm or more, more preferably 100 μm or more. The thickness of the first film 31 is, for example, 1000 μm or less, preferably 500 μm or less, more preferably 250 μm or less.

[0223] Next, in this method, a second polyurethane resin and / or its precursor is applied to the surface of the first film to form a film of the second polyurethane resin (hereinafter, second film) 32 (coating step).

[0224] The second film 32 is a resin film. The second film 32 corresponds to a second resin component (described later). The first film 32 contains a second polyurethane resin as a main component.

[0225] The second film 32 may also contain the other resins described above. The content ratio of the other resins is adjusted so that the content ratio of the other resins relative to the second composite region 22 (described below) falls within the range described below.

[0226] The second film 32 may also contain the first polyurethane resin. The content ratio of the first polyurethane resin to the second resin component (described later) is adjusted so that the content ratio of the first polyurethane resin to the second resin component (described later) falls within the range described later.

[0227] The second film 32 is preferably made of a second polyurethane resin.

[0228] There are no particular limitations on the method for forming the second film 32. For example, a polyurethane dispersion (PUD) containing the second polyurethane resin is applied to the surface of the first film 31 and then dried under appropriate conditions. In this way, the second film 32 can be formed on the surface of the first film 31.

[0229] Alternatively, for example, a polyurethane adhesive, which is a precursor of the second polyurethane resin, may be applied to the surface of the first film 31 and cured under appropriate conditions.

[0230] The thickness of the second film 32 is, for example, 0.01 mg / cm on a solids basis. 2 or more, preferably 0.1 mg / cm 2 The thickness of the second film 32 is, for example, 1.0 mg / cm on a solids basis. 2 Preferably, 0.5 mg / cm or less 2 The following is the result.

[0231] As a result, a polyurethane laminate sheet 3 comprising the first polyurethane resin and the second polyurethane resin is formed.

[0232] Next, in this method, as shown in FIG. 1C, a polyurethane laminate sheet 3 is brought into contact with a fiber assembly 2 containing reinforcing fibers (contacting step).

[0233] In this step, the second film 32 (i.e., the second polyurethane resin) is arranged so as to be in contact with the fiber assembly 2. That is, the first film 31 (first polyurethane resin), the second film 32 (second polyurethane resin), and the fiber assembly 2 are arranged in this order from one side in the thickness direction (the upper side of the paper) to the other side (the lower side of the paper).

[0234] Next, in this method, as shown in FIG. 1D, the fiber assembly 2 and the polyurethane laminate sheet 3 are heated and pressed in a laminated state (pressing step).

[0235] More specifically, in this method, a laminate of a fiber assembly 2 and a polyurethane laminate sheet 3 is heated and pressed by a known thermocompression device. Examples of the thermocompression device include an autoclave and a heat press.

[0236] The compression bonding conditions and heating conditions are set appropriately depending on the purpose and application. The compression bonding pressure is, for example, 0.1 MPa or more, preferably 0.5 MPa or more. The compression bonding pressure is, for example, 5.0 MPa or less, preferably 2.5 MPa or less. The heating temperature is, for example, 100°C or more, preferably 140°C or more, and, for example, 300°C or less, preferably 240°C or less. The compression bonding time and heating time are, for example, 0.5 minutes or more, preferably 1 minute or more. The compression bonding time and heating time are, for example, 30 minutes or less, preferably 10 minutes or less.

[0237] The environmental conditions for the bonding and heating may be a normal pressure environment or a reduced pressure environment. The reduced pressure environment includes a vacuum environment. A reduced pressure environment is preferable as the environmental condition. Under a reduced pressure environment, the generation of bubbles in the fiber-reinforced resin sheet can be suppressed.

[0238] This melts the first film 31 (first polyurethane resin) and the second film 32 (second polyurethane resin). The melted material then impregnates the fiber assembly 2 containing the reinforcing fibers. Thereafter, the first polyurethane resin, the second polyurethane resin, and the fiber assembly are cooled to room temperature.

[0239] This allows the first polyurethane resin and the second polyurethane resin to be melted and impregnated into the fiber assembly 2 of the reinforcing fibers, resulting in a fiber reinforced resin sheet 1.

[0240] 1D, the fiber reinforced resin sheet 1 includes a first composite region 21 and a second composite region 22. Furthermore, as will be described in detail later, the fiber reinforced resin sheet 1 can include a fiber region 23 (described later) and / or a resin region 24 (described later).

[0241] The first composite region 21 is formed by impregnating a fiber assembly 2 containing reinforcing fibers with a first resin component (first film 31) containing a first polyurethane resin as a main component. The second composite region 22 is formed by impregnating a fiber assembly 2 containing reinforcing fibers with a second resin component (second film 32) containing a second polyurethane resin as a main component.

[0242] The first composite region 21 is disposed, for example, on the outer side of the second composite region 22 in the thickness direction of the fiber reinforced resin sheet 1. The first composite region 21 includes reinforcing fibers and a first resin component impregnated into the reinforcing fibers.

[0243] The content of the reinforcing fibers relative to the total amount of the first composite region 21 is, for example, 50 mass% or more, preferably 60 mass% or more, more preferably 70 mass% or more. Moreover, the content of the reinforcing fibers relative to the total amount of the first composite region 21 is, for example, 95 mass% or less, preferably 90 mass% or less, more preferably 85 mass% or less.

[0244] The content (total amount) of the first resin component relative to the total amount of the first composite region 21 is, for example, 5 mass% or more, preferably 10 mass% or more, and more preferably 15 mass% or more. Furthermore, the content (total amount) of the first resin component relative to the total amount of the first composite region 21 is, for example, 50 mass% or less, preferably 40 mass% or less, and more preferably 30 mass% or less.

[0245] Furthermore, the first composite region 21 may contain additives in addition to the reinforcing fibers and the first resin component, as necessary. Examples of additives include known additives that can be contained in the first polyurethane resin. The content of the additive is, for example, 0% by mass or more relative to the total amount of the first composite region 21. The content of the additive is, for example, 20% by mass or less, preferably 10% by mass or less, and more preferably 5% by mass or less relative to the total amount of the first composite region 21.

[0246] The content (total amount) of the reinforcing fibers and the first resin component relative to the total amount of the first composite region 21 is, for example, 80 mass% or more, preferably 90 mass% or more, and more preferably 95 mass% or more. The content (total amount) of the reinforcing fibers and the first resin component relative to the total amount of the first composite region 21 is, for example, 100 mass% or less.

[0247] The first resin component is a resin component contained in the first composite region 21. In the first composite region 21, the first resin component contains a first polyurethane resin as a main component.

[0248] The term "major component" is defined as a component that accounts for more than 50% by mass of the total (hereinafter the same). The content ratio of the major component is, for example, more than 50% by mass, preferably 70% by mass or more, and more preferably 90% by mass or more. The content ratio of the major component is, for example, 100% by mass or less.

[0249] More specifically, the content of the first polyurethane resin relative to the total amount of the first resin component is, for example, more than 50% by mass, preferably 70% by mass or more, more preferably 90% by mass or more, and is, for example, 100% by mass or less.

[0250] The first resin component may contain a second polyurethane resin as a secondary component. For example, during the pressing process, the second polyurethane resin contained in the second film 32 may be mixed into the first composite region 21. In such a case, the first resin component is allowed to contain (mix with) the second polyurethane resin.

[0251] The content of the second polyurethane resin relative to the total amount of the first resin component is, for example, 0% by mass or more, and the content of the second polyurethane resin relative to the total amount of the first resin component is, for example, less than 50% by mass, preferably 30% by mass or less, and more preferably 10% by mass or less.

[0252] The first resin component may contain the above-mentioned other resins as subcomponents. The content of the other resins relative to the total amount of the first resin component is, for example, 0% by mass or more. The content of the other resins relative to the total amount of the first resin component is, for example, 10% by mass or less, preferably 5% by mass or less, and more preferably 1% by mass or less. The content of the other resins relative to the total amount of the first resin component is particularly preferably 0% by mass.

[0253] The second composite region 22 is disposed, for example, on the inner side in the thickness direction of the fiber reinforced resin sheet 1 relative to the first composite region 21. In other words, the second composite region 22 is disposed on the other side in the thickness direction relative to the side on which the first composite region 21 is formed.

[0254] The second composite region 22 includes reinforcing fibers and a second resin component impregnated into the reinforcing fibers.

[0255] The content of the reinforcing fibers relative to the total amount of the second composite region 22 is, for example, 50 mass% or more, preferably 60 mass% or more, more preferably 70 mass% or more. Moreover, the content of the reinforcing fibers relative to the total amount of the second composite region 22 is, for example, 95 mass% or less, preferably 90 mass% or less, more preferably 85 mass% or less.

[0256] The content (total amount) of the second resin component relative to the total amount of the second composite region 22 is, for example, 5 mass% or more, preferably 10 mass% or more, and more preferably 15 mass% or more. Furthermore, the content (total amount) of the second resin component relative to the total amount of the second composite region 22 is, for example, 50 mass% or less, preferably 40 mass% or less, and more preferably 30 mass% or less.

[0257] Furthermore, the second composite region 22 may contain additives in addition to the reinforcing fibers and the second resin component, as necessary. Examples of additives include known additives that can be contained in the polyurethane dispersion. The content of the additive is, for example, 0% by mass or more relative to the total amount of the second composite region 22. The content of the additive is, for example, 20% by mass or less, preferably 10% by mass or less, and more preferably 5% by mass or less relative to the total amount of the second composite region 22.

[0258] The content (total amount) of the reinforcing fibers and the second resin component relative to the total amount of the second composite region 22 is, for example, 80 mass% or more, preferably 90 mass% or more, and more preferably 95 mass% or more. The content (total amount) of the reinforcing fibers and the second resin component relative to the total amount of the second composite region 22 is, for example, 100 mass% or less.

[0259] The second resin component is a resin component contained in the second composite region 22. In the second composite region 22, the second resin component contains a second polyurethane resin as a main component.

[0260] More specifically, the content of the second polyurethane resin relative to the total amount of the second resin component is, for example, more than 50% by mass, preferably 70% by mass or more, more preferably 90% by mass or more, and is, for example, 100% by mass or less.

[0261] The second resin component may contain a first polyurethane resin as a secondary component. For example, during the pressing process, the first polyurethane resin contained in the first film 31 may be mixed into the second composite region 22. In such a case, the inclusion (mixing) of the first polyurethane resin in the second resin component is permitted.

[0262] The content of the first polyurethane resin relative to the total amount of the second resin component is, for example, 0% by mass or more, and the content of the first polyurethane resin relative to the total amount of the second resin component is, for example, less than 50% by mass, preferably 30% by mass or less, and more preferably 10% by mass or less.

[0263] The second resin component may contain the above-mentioned other resins as subcomponents. The content of the other resins relative to the total amount of the second resin component is, for example, 0% by mass or more. The content of the other resins relative to the total amount of the second resin component is, for example, 10% by mass or less, preferably 5% by mass or less, and more preferably 1% by mass or less. The content of the other resins relative to the total amount of the second resin component is particularly preferably 0% by mass.

[0264] The impregnation depth of the first polyurethane resin and the second polyurethane resin into the fiber assembly 2 of the reinforcing fibers is appropriately set depending on the thickness of the polyurethane laminate sheet 3 and the heating conditions during pressure bonding.

[0265] In other words, the first polyurethane resin and the second polyurethane resin may be impregnated from one side in the thickness direction of the fiber aggregate 2 of the reinforcing fibers to a predetermined depth. That is, the first polyurethane resin and the second polyurethane resin may be impregnated on the other side of the reinforcing fibers in the thickness direction of the fiber aggregate 2. Furthermore, the first polyurethane resin and the second polyurethane resin may not be impregnated on the other side of the reinforcing fibers in the thickness direction of the fiber aggregate 2 of the reinforcing fibers in the thickness direction of the fiber aggregate 2.

[0266] The first polyurethane resin and the second polyurethane resin may be impregnated into the central portion (the middle portion between one side and the other side) of the reinforcing fiber aggregate 3 in the thickness direction. The first polyurethane resin and the second polyurethane resin may not be impregnated into the central portion of the reinforcing fiber aggregate 3 in the thickness direction.

[0267] That is, although not shown, the entire fiber assembly 2 of the reinforcing fibers in the thickness direction may be impregnated with the first polyurethane resin and / or the second polyurethane resin (total impregnation).

[0268] In such a case, the fiber reinforced resin sheet 1 is made up of regions (first composite region 21 and second composite region 22) in which the fiber assembly is impregnated with the first polyurethane resin and / or the second polyurethane resin.

[0269] 1D, for example, the first polyurethane resin and / or the second polyurethane resin may be impregnated only in a portion of the thickness direction of the reinforcing fiber fiber assembly 2. In other words, the remaining portion of the thickness direction of the fiber assembly 2 may not be impregnated with the first polyurethane resin and the second polyurethane resin (semi-impregnated).

[0270] In such a case, the fiber reinforced resin sheet 1 has regions (first composite region 21 and second composite region 22) in which the fiber aggregate 2 is impregnated with the first polyurethane resin and / or the second polyurethane resin, and regions (fiber region) 23 in which the fiber aggregate 2 is not impregnated with the first polyurethane resin and the second polyurethane resin.

[0271] From the viewpoint of further improving flexibility, the fiber reinforced resin sheet preferably includes a first composite region 21, a second composite region 22, and a fiber region 23. More specifically, the central portion in the thickness direction of the fiber assembly 2 of the reinforcing fibers is preferably the fiber region 23. In other words, the central portion is not impregnated with the first polyurethane resin and the second polyurethane resin. The impregnation state of the first polyurethane resin and the second polyurethane resin can be confirmed and determined, for example, by observing the cross section of the fiber reinforced resin sheet 1 with a scanning electron microscope.

[0272] The fiber region 23 is arranged, for example, further inward than the second composite region 21 in the thickness direction of the fiber reinforced resin sheet 3. In other words, the second composite region 22 is arranged on at least one side in the thickness direction of the fiber region 23. Furthermore, the first composite region 21 is arranged on at least one side in the thickness direction of the second composite region 22. In other words, the first composite region 21 is arranged on the opposite side of the second composite region 22 from the side on which the fiber region 23 is arranged.

[0273] The fiber region 23 contains reinforcing fibers. More specifically, the content (total amount) of the reinforcing fibers relative to the total amount of the fiber region 23 is, for example, 90 mass% or more, preferably 95 mass% or more, and more preferably 99 mass% or more. Furthermore, the content (total amount) of the reinforcing fibers relative to the total amount of the fiber region 23 is, for example, 100 mass% or less.

[0274] Furthermore, the fiber region 23 may contain a resin. The resin may contain, for example, a first polyurethane resin and / or a second polyurethane resin. For example, in the above-mentioned pressing step, the first polyurethane resin and / or the second polyurethane resin may be mixed into the fiber region 23. In such a case, the inclusion (mixing) of the first polyurethane resin and / or the second polyurethane resin in the fiber region 23 is permitted.

[0275] The resin content (total amount) relative to the total amount of the fiber region 23 is, for example, 0% by mass or more. Furthermore, the resin content (total amount) relative to the total amount of the fiber region 23 is, for example, 10% by mass or less, preferably 5% by mass or less, and more preferably 1% by mass or less.

[0276] Preferably, the fiber region 23 is substantially free of resin. When the resin content (total amount) relative to the total amount of the fiber region 23 is 1 mass % or less, the fiber region 23 is defined as being substantially free of resin.

[0277] 1D, a portion of the first polyurethane resin may not be impregnated into the fiber aggregates 2. In other words, the fiber reinforced resin sheet 1 can have a region (resin region) 24 that does not contain the fiber aggregates 2 but contains the first polyurethane resin. The resin region 24 can suppress fuzzing of the fiber reinforced resin sheet 1 caused by the fiber aggregates 2.

[0278] The resin region 24 is disposed, for example, further outside than the first composite region 21 in the thickness direction of the fiber reinforced resin sheet 3. That is, the resin region 24 is a surface layer of the fiber reinforced resin sheet 3.

[0279] The content (total amount) of the first polyurethane resin relative to the total amount of the resin regions 24 is, for example, 90% by mass or more, preferably 95% by mass or more, and more preferably 99% by mass or more. Furthermore, the content (total amount) of the first polyurethane resin relative to the total amount of the resin regions 24 is, for example, 100% by mass or less.

[0280] Furthermore, the resin region 24 may contain reinforcing fibers. For example, in the above-described pressing step, fluffing may occur in the fiber assembly 2, and the fluff of the reinforcing fibers may be mixed into the resin region 24. In such a case, the inclusion (mixing) of reinforcing fibers in the resin region 24 is permitted.

[0281] The content (total amount) of the reinforcing fibers relative to the total amount of the resin regions 24 is, for example, 0% by mass or more. Furthermore, the content (total amount) of the reinforcing fibers relative to the total amount of the resin regions 24 is, for example, 10% by mass or less, preferably 5% by mass or less, and more preferably 1% by mass or less.

[0282] Preferably, the resin region 24 is substantially free of reinforcing fibers. When the content (total amount) of reinforcing fibers relative to the total amount of the resin region 24 is 1 mass % or less, the resin region 24 is defined as being substantially free of resin.

[0283] In such a fiber reinforced resin sheet 1, the second composite region 22 is disposed on at least one side in the thickness direction of the fiber region 23. Furthermore, the first composite region 21 is disposed on the opposite side (one side in the thickness direction) of the second composite region 22 from the side on which the fiber region 23 is disposed. That is, the first composite region 21, the second composite region 22, and the fiber region 23 are disposed in this order from one side in the thickness direction (the upper side of the paper) to the other side (the lower side of the paper). Such a fiber reinforced resin sheet 1 can achieve particularly excellent bending recovery.

[0284] 1A to 1D, a polyurethane laminate sheet 3 can be pressed and heated onto only one side of a fiber assembly 2 of reinforcing fibers. In this case, the polyurethane laminate sheet 3 penetrates to a predetermined depth from one side to the other side in the thickness direction of the fiber assembly 2 of reinforcing fibers.

[0285] In the manufacture of the fiber-reinforced resin sheet 1, the polyurethane laminate sheet 3 can be pressed and heated onto both sides of the fiber assembly 2 of the reinforcing fibers. In this case, as shown in Fig. 2, the polyurethane laminate sheet 3 penetrates to a predetermined depth from one side to the other in the thickness direction of the fiber assembly 2 of the reinforcing fibers. At the same time, the polyurethane laminate sheet 3 also penetrates to a predetermined depth from the other side to one side in the thickness direction of the fiber assembly 2 of the reinforcing fibers.

[0286] Preferably, polyurethane laminate sheets 3 are pressed and heated onto both sides of the fiber assembly 2 of reinforcing fibers. In this case, a first composite region 21 and a second composite region 22 are formed on one side and the other side of the fiber reinforced resin sheet 1 in the thickness direction, respectively. Furthermore, a fiber region 23 is formed in the center of the fiber reinforced resin sheet 1 as needed. Such a fiber reinforced resin sheet 1 has particularly excellent mechanical strength.

[0287] As described above, the polyurethane laminate sheet 3 impregnates (penetrates) the fiber assembly 2, whereby the first composite region 21, the second composite region 22, and the fiber region 23 are formed in this order from the outside of the fiber reinforced resin sheet 1.

[0288] The first composite region 21, the second composite region 22, and the fiber region 23 may be visually indistinguishable. An intermediate region may be formed between the first composite region 21 and the second composite region 22. An intermediate region may be formed between the second composite region 22 and the fiber region 23. The intermediate region may be formed, for example, by compatibility between the first polyurethane resin and the second polyurethane resin. The intermediate region may be formed, for example, by variations in the impregnation (penetration) depth of the polyurethane laminate sheet 3 into the fiber assembly 2.

[0289] The range of the first composite region 21, the range of the second composite region 22, the range of the fiber region 23, and the range of the resin region 24 are determined based on the reinforcing fiber content, the resin content, the first polyurethane resin content, and the second polyurethane resin content.

[0290] Furthermore, although not shown, in the production of the fiber reinforced resin sheet 1, a release film can be laid on the outside of the polyurethane laminate sheet during the above-mentioned pressurization. This improves workability and also results in a fiber reinforced resin sheet 1 with excellent appearance. Furthermore, the surface shape of the release film can be processed as desired. For example, the surface of the release film can be embossed. This improves the appearance of the fiber reinforced resin sheet 1. Furthermore, although not shown, a surface protection layer can be further laminated on the first composite region 21 (or resin region 24). In other words, the first composite region 21 (or resin region 24) does not have to be the outermost surface of the fiber reinforced resin sheet 1.

[0291] The fiber reinforced resin sheet 1 is cured as necessary. The curing temperature is, for example, 40°C or higher, preferably 80°C or higher. The curing temperature is, for example, 140°C or lower, preferably 120°C or lower. The curing time is, for example, 30 minutes or longer, preferably 1 hour or longer. The curing time is, for example, 7 days or shorter, preferably 3 days or shorter.

[0292] 3. Effects The fiber-reinforced resin sheet includes a fiber assembly and a resin impregnated into the fiber assembly. The resin includes a first polyurethane resin that does not contain urea bonds or crosslinked structures, and a second polyurethane resin that contains urea bonds and / or crosslinked structures. The fiber-reinforced resin sheet includes a first composite region and a second composite region. The first composite region includes reinforcing fibers and a first resin component, and the first resin component contains the first polyurethane resin as a main component. The second composite region includes reinforcing fibers and a second resin component, and the second resin component contains the second polyurethane resin as a main component. Such a fiber-reinforced resin sheet has excellent sewing durability.

[0293] In the above-described method for producing a fiber-reinforced resin sheet, a polyurethane laminate sheet is brought into contact with a fiber assembly containing reinforcing fibers, and the two are heated and pressurized. The polyurethane laminate sheet is formed by laminating a first polyurethane resin that does not contain urea bonds or crosslinked structures and a second polyurethane resin that contains urea bonds and / or crosslinked structures. The second polyurethane resin is arranged so as to contact the fiber assembly. The first polyurethane resin and the second polyurethane resin are melted and impregnated into the fiber assembly. This method for producing a fiber-reinforced resin sheet can produce a fiber-reinforced resin sheet with excellent sewing resistance.

[0294] As a result, the fiber-reinforced resin sheet is suitable for use in various industrial fields. Fields in which the fiber-reinforced resin sheet is used include, for example, the fields of accessories, vehicles, furniture, sports, robots, office supplies, architecture, healthcare, and electrical appliances. Preferably, the fiber-reinforced resin sheet is used in the field of accessories. Examples of accessories include bags, wallets, and business card holders. [Example]

[0295] Next, the present invention will be described based on examples and comparative examples, but the present invention is not limited thereto. Note that "parts" and "%" are by mass unless otherwise specified. Furthermore, specific numerical values ​​such as blending ratios (content ratios), physical property values, and parameters used in the following description can be substituted with the corresponding upper limit values ​​(numeric values ​​defined as "equal to or less than") or lower limit values ​​(numeric values ​​defined as "equal to or more than" or "exceeding") of the blending ratios (content ratios), physical property values, and parameters described in the above "Modes for Carrying Out the Invention."

[0296] 1. Fiber assembly <Preparation Example A1 Carbon Fiber> As the fiber assembly, a woven fabric (commercially available) made of the following carbon fibers was prepared. EC3C: Product name EC3C, manufactured by FORMOSA TAFFETA, thickness 270 μm

[0297] 2. First polyurethane resin <Preparation Example B1 Film> (1) Raw materials The following ingredients were prepared as raw materials for the first polyurethane resin film.

[0298] Diisocyanate (A) 1,4-H6XDI: 1,4-bis(isocyanatomethyl)cyclohexane, 1,4-H6XDI obtained in accordance with the description of Production Example 3 in International Publication WO2019 / 069802 The purity of 1,4-H6XDI was measured by gas chromatography. The purity was 99.9%. The hue was measured by APHA measurement. The hue was 5. 13 The ratio of trans isomer to cis isomer was measured by C-NMR, and it was found that the trans isomer accounted for 86 mol % and the cis isomer accounted for 14 mol %.

[0299] Macrodiol (B) PTMEG: Polytetramethylene ether glycol, number average molecular weight (Mn) 1000, trade name PTG1000, average number of hydroxyl groups 2, manufactured by Korea PTG

[0300] Low molecular weight diol (C) 1,4-BD: 1,4-butanediol, manufactured by Mitsubishi Chemical Corporation

[0301] Catalyst (D) Dibutyltin dilaurate; product name Neostan U-100, manufactured by Nitto Chemical Co., Ltd.

[0302] Catalyst Diluent (E) Diisononyl adipate (trade name DINA, manufactured by Daihachi Chemical Industry Co., Ltd.)

[0303] Additive (F) Antioxidant: hindered phenol compound, trade name Irganox 245, manufactured by BASF Japan Ltd. UV absorber: benzotriazole compound, trade name Tinuvin 571, manufactured by BASF Japan Ltd. Weathering stabilizer: hindered amine compound, trade name Adekastab LA-72, manufactured by ADEKA Corporation

[0304] (2) Manufacturing method A first polyurethane resin was produced by the following method.

[0305] That is, 100 moles of macrodiol (B) and additive (F) were mixed. The mixture was placed in a container filled with nitrogen and heated at 100°C for 12 hours. The amount of additive (F) was adjusted as follows:

[0306] Antioxidant: 0.3% by weight based on the final weight of the polyurethane film UV absorber: 0.3% by weight based on the final weight of the polyurethane film Weathering stabilizer: 0.3% by weight based on the final weight of the polyurethane film

[0307] On the other hand, the catalyst (D) was diluted with a catalyst diluent (E) to obtain a catalyst solution, the catalyst concentration of which was adjusted to 4 mass %.

[0308] A container equipped with a stirrer, thermometer, and nitrogen inlet tube was prepared. 161 moles of diisocyanate (A) was placed in this container. A mixture of 100 moles of macrodiol (B) and additive (F) was also placed in this container. Then, in the container, the diisocyanate (A), 100 moles of macropolyol (B), and additive (F) were mixed using a high-speed stirring disperser. This caused the diisocyanate (A) and macrodiol (B) to react, resulting in an isocyanate-terminated prepolymer.

[0309] The mixing and reaction conditions were as follows: Mixing conditions: 85°C water bath, 5 minutes, 500-700 rpm

[0310] Next, 63 moles of low-molecular-weight diol (C) (equivalent ratio NOC / OH = 0.99) was added as a chain extender to the isocyanate-terminated prepolymer, and these were mixed using a high-speed mixing disper until the temperature of the mixture reached 90°C. During the mixing, a catalyst solution was added at an appropriate rate.

[0311] Next, the mixture of the isocyanate group-terminated prepolymer and the low-molecular-weight diol (C) was poured into a Teflon (registered trademark) tray and subjected to a urethane reaction at 150°C for 2 hours, and then to a further urethane reaction at 100°C for 20 hours, thereby obtaining a first polyurethane resin.

[0312] (3) Molding method A film of the first polyurethane resin was produced by the following method.

[0313] That is, the first polyurethane resin was removed from the vat. The first polyurethane resin was cut into cubes using a bale cutter. The cube-shaped first polyurethane resin was then crushed using a crusher. As a result, crushed pellets were obtained.

[0314] The pulverized pellets were then heat-treated at 80°C for 5 days. The pulverized pellets were then dried at 80°C for 12 hours under reduced pressure. The pulverized pellets were then placed in a single-screw extruder (model: SZW20-25MG, manufactured by Technobel Co., Ltd.). A strand was extruded at a screw rotation speed of 30 rpm and a cylinder temperature of 140 to 240°C. The strand was then cut. This resulted in pellets of the first polyurethane resin (pellets for molding).

[0315] Next, the pellets of the first polyurethane resin were used to obtain a film of the first polyurethane resin.

[0316] More specifically, pellets of the first polyurethane resin were dried under reduced pressure in vacuum at 80°C for 12 hours. The pellets of the first polyurethane resin were then charged into a single-screw extruder (model: SZW20-25MG, manufactured by Technovel Co., Ltd.). The first polyurethane resin was then extruded through a T-die at a screw rotation speed of 20 rpm and a cylinder temperature of 140 to 240°C, and taken up by a belt conveyer.

[0317] This resulted in a film of the first polyurethane resin (hereinafter referred to as polyurethane film). The polyurethane film was then aged for 7 days under constant temperature and humidity conditions of room temperature 23°C and relative humidity 55%. The polyurethane film had a thickness of 150 μm.

[0318] (4)Chemical structure The first polyurethane resin is a reaction product of 1,4-H6XDI having an average number of isocyanate groups of 2, PTMEG having an average number of hydroxyl groups of 2, and 1,4-BG having an average number of hydroxyl groups of 2. Therefore, the first polyurethane resin has a linear structure and is not crosslinked.

[0319] Furthermore, PTMEG contains hydroxyl groups but does not contain amino groups, and 1,4-BG contains hydroxyl groups but does not contain amino groups, so the first polyurethane resin contains a urethane structure but does not contain a urea structure.

[0320] The hard segment concentration and urethane group concentration of the first polyurethane resin were calculated based on the blending ratio (charge) of each component. The hard segment concentration of the first polyurethane resin was 13 mass %. The urethane group concentration was 2.3 mmol / g.

[0321] The hard segment concentration was calculated by the following formula. Formula: [Mass (g) of low molecular weight polyol (C) + (Mass (g) of low molecular weight polyol (C) / Molecular weight (g / mol) of low molecular weight polyol (C)) × Average molecular weight (g / mol) of polyisocyanate (A)] ÷ (Mass (g) of polyisocyanate (A) + Mass (g) of macropolyol (B) + Mass (g) of low molecular weight polyol (C)) × 100

[0322] (5) Physical property measurement <Heat Amount / Heat Zone> The heat of fusion of the first polyurethane resin was measured using a differential scanning calorimeter (DSC7000X, manufactured by Hitachi High-Tech Science) as follows.

[0323] That is, about 10 mg of the first polyurethane resin was placed in an aluminum pan. This aluminum pan was covered with a cover and crimped, which was used as a measurement sample. Similarly, alumina was collected and used as a reference sample.

[0324] The sample and reference were then set in their designated positions in the cell, and the sample was cooled from 20°C to -100°C at a rate of 10°C / min under a nitrogen flow of 30 NmL / min. After holding at that temperature for 5 minutes, the sample was heated to 270°C at a rate of 10°C / min, and then cooled to -70°C at a rate of 10°C / min.

[0325] Among the peaks appearing during the temperature drop from 270°C to -70°C, the exothermic peak (recrystallization peak) between 50°C and 180°C was determined as the recrystallization peak of the urethane group. The peak width was determined as the exothermic range (°C). Furthermore, the heat quantity (enthalpy change) (mJ / mg) at the recrystallization peak was measured.

[0326] Further, the value was calculated from the calorific value (mJ / mg) of the recrystallization peak of the urethane group and the exothermic section (° C.) using the following formula. [Exothermic energy of the urethane group recrystallization peak (mJ / mg) ÷ exothermic interval (℃)]

[0327] As a result, the value of [exothermic value (mJ / mg) of the recrystallization peak of the urethane group ÷ exothermic interval (°C)] was 0.22. 3. Second polyurethane resin <Preparation Examples C1 to C7 Polyurethane Dispersion (PUD)> (1) Raw materials The following components were prepared as polyurethane dispersion (PUD) raw materials:

[0328] Polyisocyanate (A) 1,3-H6XDI; 1,3-bis(isocyanatomethyl)cyclohexane, trade name Takenate 600, manufactured by Mitsui Chemicals, Inc. IPDI: Isophorone diisocyanate, manufactured by EVONIC

[0329] Macropolyol (B) UH200: Polycarbonate diol, 2000, product name ETERNACOLL UH-200, manufactured by Ube Industries, Ltd. U5620: Polyester diol obtained by condensation polymerization of adipic acid, 1,6-hexanediol, and neopentyl glycol, 2000, trade name Takelac U-5620, manufactured by Mitsui Chemicals, Inc. T6002: Polycarbonate diol, 2000, trade name DURANOL T6002, manufactured by Asahi Kasei Corporation PTG650SN: Polytetramethylene ether glycol, 650, trade name PTG650SN, manufactured by Hodogaya Chemical Co., Ltd. PTG2000S: Polytetramethylene ether glycol, 2000, product name PTG2000S, manufactured by Ube Industries, Ltd.

[0330] Low molecular weight polyol (C) Terathan 250: Polytetramethylene ether glycol, 250, product name TERATHANE 250, manufactured by INVISTA TEG; Triethylene glycol DMPA; Dimethylolpropionic acid NPG; neopentyl glycol

[0331] Solvent (D) AN; acetonitrile EA; Ethyl acetate MEK; methyl ethyl ketone Acetone; Acetone

[0332] Neutralizer (E) TIPA; Triisopropanolamine TEA; Triethylamine

[0333] Catalyst (F) St; tin 2-ethylhexanoate DBU; Diazabicycloundecane

[0334] Chain extender (G) HYD; Hydrazine monohydrate, polyamine A-EA: N-(β-aminoethyl)ethanolamine, amino alcohol, trade name Amino Alcohol EA, manufactured by Nippon Nyukazai Co., Ltd. KBM602: N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, trade name KBM602, an alkoxysilyl compound having a primary amino group and a secondary amino group, manufactured by Shin-Etsu Chemical Co., Ltd.

[0335] (2) Manufacturing method Polyurethane dispersions (PUD) A to G were prepared by the following method.

[0336] Specifically, polyisocyanate (A), macropolyol (B), low-molecular-weight polyol (C), solvent (D), and catalyst (F) were prepared according to the formulations shown in Table 1. These were placed in a four-neck flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen inlet tube, and mixed. This allowed the polyisocyanate (A), macropolyol (B), and low-molecular-weight polyol (C) to react at 70°C under a nitrogen atmosphere.

[0337] In the preparation of polyurethane dispersions (PUD) A to E and G, the equivalent ratio (NCO / OH) of the above reaction was 1.4. In the preparation of polyurethane dispersion (PUD) F, the equivalent ratio (NCO / OH) of the above reaction was 1.6.

[0338] The disappearance of the active hydrogen groups was confirmed by amine titration. The reaction was continued until all the active hydrogen groups had disappeared, thereby obtaining an isocyanate-terminated prepolymer.

[0339] The isocyanate-terminated prepolymer was cooled to 40°C. The isocyanate-terminated prepolymer was then dispersed in the aqueous dispersion shown in the table using a homodisper. If necessary, a chain extender (A-EA) was added to the aqueous dispersion. The isocyanate-terminated prepolymer was also neutralized with the neutralizer (E) shown in the table. This resulted in a dispersion of the isocyanate-terminated prepolymer.

[0340] Thereafter, the chain extender solution shown in the table was added to the dispersion of the isocyanate-terminated prepolymer, thereby causing a chain extension reaction of the isocyanate-terminated prepolymer.

[0341] When two types of chain extender solutions were used, they were added sequentially. More specifically, chain extender solution 1 in the table was added first, and chain extender solution 2 in the table was added last.

[0342] After the chain extension reaction, the reaction product liquid was aged for 1 hour. The solvent (D) and water were then removed from the reaction product liquid using an evaporator. Ion-exchanged water was then added to the reaction product liquid to adjust the solids concentration to 30% by mass. This resulted in a polyurethane dispersion (PUD) of a second polyurethane resin.

[0343] The polyurethane dispersion (PUD) of the second polyurethane resin is a coating liquid of the second polyurethane resin.

[0344] (3)Chemical structure In the production of PUD, the chain extender (G) contains an amino group, and therefore the second polyurethane resin contains a urea structure.

[0345] Furthermore, when the chain extender (G) contains KBM602 (N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane), the second polyurethane resin contains a urea structure and a crosslinked structure.

[0346] <Preparation Example C8 Adhesive> (1) Type The following moisture-curable polyurethane adhesives were prepared: A-260: Takenate A-260, manufactured by Mitsui Chemicals, moisture-curing polyurethane adhesive

[0347] The moisture-curable polyurethane adhesive was dispersed in a solvent (ethyl acetate) and the solid content was adjusted to 30% by mass, thereby obtaining a coating liquid of a second polyurethane resin.

[0348] (2)Chemical structure Takenate A-260 is a moisture-curing polyurethane adhesive that forms a crosslinked structure upon curing. In other words, Takenate A-260 forms a second polyurethane resin upon moisture curing.

[0349] <Comparison preparation example C9~C10> (1) Type The following resins were prepared in place of polyurethane dispersion (PUD) and moisture-curing polyurethane adhesive. SA-110: Chemipearl SA-110, manufactured by Mitsui Chemicals, Inc., modified polyolefin aqueous dispersion V-200: Product name: Chemipearl V-200, manufactured by Mitsui Chemicals, Inc., ethylene-vinyl acetate copolymer aqueous dispersion

[0350] These were then dispersed in a solvent (ion-exchanged water) and the solid content was adjusted to 30% by mass, thereby obtaining a coating liquid for the second polyurethane resin.

[0351] (2)Chemical structure Chemipearl SA-110 and Chemipearl V-200 do not contain crosslinked structures or urea bonds. Furthermore, Chemipearl SA-110 and Chemipearl V-200 do not form crosslinked structures or urea bonds upon curing. Therefore, Chemipearl SA-110 and Chemipearl V-200 do not form a second polyurethane resin.

[0352] 4. Fiber-reinforced resin sheet <Examples 1 to 9 and Comparative Examples 1 to 3> The surface of the first polyurethane resin film (Preparation Example A1) was coated with and impregnated with a coating solution of the second polyurethane resin (Preparation Examples B1 to B10, solid content 30% by mass). The coating amount (dry mass) was 0.3 mg / cm. 2 was adjusted to.

[0353] The coating liquid was then dried for 2 minutes in a hot air dryer at 110° C. This resulted in a polyurethane laminate sheet comprising a film of the first polyurethane resin and a coating layer of the second polyurethane resin.

[0354] In Comparative Example 3, the coating liquid of the second polyurethane resin was not applied to the film of the first polyurethane resin.

[0355] Next, both sides of the fiber assembly (EC3C) were sandwiched between polyurethane laminate sheets. More specifically, the fiber assembly and the polyurethane laminate sheets were placed in contact with each other so that the second polyurethane resin was facing the fiber assembly.

[0356] The fiber assembly and polyurethane laminate sheet were then heated to 150°C using a heat press (Kansai Roll two-stage heating and cooling press) and pressed for 5 minutes at the pressure shown in Table 2. When pressing, a TPX (registered trademark, polymethylpentene) film was placed on the outside of the polyurethane laminate sheet as a release film.

[0357] This melted the coating layer of the second polyurethane resin and allowed it to impregnate the fiber assembly. The film of the first polyurethane resin was also melted and allowed it to impregnate the fiber assembly. More specifically, the first polyurethane resin and the second polyurethane resin were impregnated into the fiber assembly from both sides in the thickness direction of the fiber assembly.

[0358] Thereafter, the fiber assembly impregnated with the first polyurethane resin and the second polyurethane resin was cooled to 25° C. In this way, a fiber reinforced resin sheet was obtained.

[0359] 5. Evaluation The fiber-reinforced resin sheets of each Example and Comparative Example were evaluated by the following methods. The results are shown in Table 2.

[0360] (1) Peeling resistance (peel marks) Using a sewing machine (manufactured by Brother Corporation), a needle (household size No. 16) was pierced into the fiber reinforced resin sheet. The needle was then removed from the fiber reinforced resin sheet. The area around the needle hole was then observed to evaluate the condition of the fiber reinforced resin sheet.

[0361] More specifically, after the needles were removed, the fiber-reinforced resin sheet was photographed. The photographed image was then binarized into black and white. The area of ​​the white portion in the photograph (area per hole, mm 2 The area of ​​the white part was calculated. The 50 holes were also observed as described above. The average area of ​​the white part was then calculated.

[0362] The white areas indicate areas where the resin has peeled off from the fiber aggregate. Therefore, the smaller the area of ​​the white areas, the better the peel resistance of the fiber-reinforced resin sheet.

[0363] (2) Bending resistance The bending resistance was evaluated by the slide method in accordance with JIS L 1096 (2020). More specifically, a testing machine described in "8.21.2 B Method (Slide Method)" of JIS L 1096 (2020) was used. Also, δ was measured for a 150 mm × 20 mm test piece, with l set to 100.

[0364] Then, a test was performed on a 150 mm x 20 mm test piece using the above δ value, and the l value was measured. If the l value exceeded 10 mm, it was marked as ○. If the l value was 10 mm or less, it was marked as ×.

[0365] (3) Coating suitability When the second polyurethane resin was applied to the film of the first polyurethane resin, the state of the coating liquid was checked and evaluated according to the following criteria.

[0366] A: The coating liquid is not seen to be repelled from the film. B: The coating liquid is observed to be repelled from the film, but the coating liquid spreads over the entire surface of the film. C: The coating liquid is observed to be repelled from the film. Furthermore, the coating liquid does not spread over the entire surface of the film.

[0367] (4) Impregnation state The fiber-reinforced resin sheet was cut in the thickness direction. The cross section was then observed with a scanning electron microscope (VHX-D510, manufactured by Keyence Corporation). This allowed confirmation and evaluation of the state of resin impregnation into the fiber assembly.

[0368] As a result, in all of Examples 1 to 8 and Comparative Examples 1 to 3, the resin was not impregnated into the central portion in the thickness direction of the fiber assembly.

[0369] [Table 1]

[0370] [Table 2]

Claims

1. A fiber assembly including reinforcing fibers; a resin impregnated on at least one surface of the fiber assembly; A fiber reinforced resin sheet comprising: The resin is a first polyurethane resin that does not contain a urea bond or a crosslinked structure; a second polyurethane resin containing a urea bond and / or a crosslinked structure; Including, The fiber reinforced resin sheet is A first composite region and a second composite region are provided, the first composite region includes the reinforcing fibers and a first resin component impregnated into the reinforcing fibers, the first resin component including the first polyurethane resin as a main component, The second composite region includes the reinforcing fibers and a second resin component impregnated into the reinforcing fibers, and the second resin component includes the second polyurethane resin as a main component. , fiber reinforced resin sheet.

2. The fiber reinforced resin sheet further comprises: a fiber region containing the reinforcing fibers and substantially not containing the resin; the second composite region is disposed on at least one side of the fiber region; The fiber-reinforced sheet according to claim 1 , wherein the first composite region is disposed on the opposite side of the second composite region from the side on which the fiber region is disposed.

3. The fiber-reinforced sheet according to claim 1 , wherein the second polyurethane resin contains urea bonds.

4. The fiber-reinforced sheet according to claim 1 , wherein the second polyurethane resin contains urea bonds and a crosslinked structure.

5. the first polyurethane resin comprises a reaction product of a first raw material component comprising a diisocyanate component and a diol component; The fiber-reinforced sheet according to claim 1 , wherein the diisocyanate component comprises a monocyclic alicyclic diisocyanate.

6. The fiber-reinforced resin sheet according to claim 5, wherein the monocyclic alicyclic diisocyanate includes 1,4-bis(isocyanatomethyl)cyclohexane.

7. The fiber reinforced resin sheet according to claim 6, wherein the 1,4-bis(isocyanatomethyl)cyclohexane contains a trans isomer in a proportion of 80 mol% or more.

8. The diol component contains a macrodiol, The fiber reinforced resin sheet according to claim 5, wherein the number average molecular weight of the macrodiol is 400 or more and 3000 or less.

9. The fiber reinforced resin sheet according to claim 1, wherein the hard segment concentration of the first polyurethane resin is 8% by mass or more and 55% by mass or less.

10. The fiber reinforced resin sheet according to claim 1, wherein the first polyurethane resin has a urethane group concentration of 1.7 mmol / g or more and 4.5 mmol / g or less.

11. The fiber reinforced resin sheet according to claim 1, wherein the first polyurethane resin satisfies the following formula (1): Formula (1): 0<[heat release amount (mJ / mg) of the recrystallization peak of the urethane group ÷ heat release section (°C)] <0.85

12. The fiber-reinforced resin sheet according to claim 1, wherein the reinforcing fibers include carbon fibers and / or aramid fibers.

13. A preparation step of preparing a fiber assembly containing reinforcing fibers and a polyurethane laminate sheet; a contacting step of contacting the polyurethane laminate sheet with the fiber assembly containing reinforcing fibers; a pressing step of heating and pressurizing a fiber assembly containing reinforcing fibers and a polyurethane laminated sheet; Equipped with The polyurethane laminate sheet is a first polyurethane resin that does not contain a urea bond or a crosslinked structure; a second polyurethane resin containing a urea bond and / or a crosslinked structure; are stacked, In the contacting step, a second polyurethane resin is disposed so as to be in contact with the fiber aggregate; In the pressing step, The first polyurethane resin and the second polyurethane resin are melted and impregnated into the fiber assembly. , a method for manufacturing a fiber-reinforced resin sheet.

14. The preparation step includes: a film preparation step of preparing a film of the first polyurethane resin; a coating step of coating the second polyurethane resin and / or a precursor thereof onto the film; The method for manufacturing a fiber-reinforced resin sheet according to claim 13, comprising:

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