CFRP molding profiles

Abstract

To provide a molding mold material having excellent dimensional stability as well as high tensile strength.SOLUTION: A CFRP molding mold material comprises a molded article which at least contains xonotlite-based calcium silicate, an acrylic resin, and an inorganic fibrous grain, wherein in the molded article, a content rate of the xonotlite-based calcium silicate is 50-80 mass%, a content rate of the acrylic resin is 6-15 mass%, and a content rate of the inorganic fibrous grain is 10-30 mass%.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a profile for CFRP molding.

Background Art

[0002] CFRP (Carbon Fiber Reinforced Plastics) is a composite material of resin and carbon fiber, and has excellent strength and rigidity. Therefore, it is widely used in various applications such as civil engineering, automobiles, aircraft, and medical devices, and is one of the materials with extremely high utility value in the industry.

[0003] Various methods for molding CFRP are known, and typically, the autoclave molding method can be mentioned. In such an autoclave molding method, a mold is used to obtain a CFRP molded body having a desired shape. Generally, a metal mold is used for mass production as the mold, and when manufacturing a prototype CFRP molded body, a calcium silicate molded body with good machinability and low material cost is used. For example, Patent Document 1 proposes a mold base material for CFRP molding containing a calcium silicate hydrate (binder) composed of a predetermined CaO / SiO2 ratio, glass fiber, and an inorganic filler containing a lubricant.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, molded articles containing calcium silicate had a problem in that their dimensions were easily altered by factors such as moisture absorption. In addition, it was required that the mold not break when demolding the CFRP from the mold, but conventional molded articles containing calcium silicate did not have sufficient tensile strength (interlaminar strength), making them prone to breakage during demolding. From this perspective, there was a need for a mold material (mold base material) for CFRP molding that had excellent dimensional stability and high tensile strength.

[0006] The present invention has been made in view of the above, and aims to provide a molding material that has excellent dimensional stability and high tensile strength. [Means for solving the problem]

[0007] The inventors of this invention conducted extensive research to achieve the above objectives and, as a result, discovered that the above objectives can be achieved by a molded article containing xonotlite-based calcium silicate, acrylic resin, and inorganic fibrous particles in predetermined proportions, thus completing the present invention.

[0008] In other words, the present invention encompasses, for example, the subject matter described in the following sections. Item 1 A mold material for CFRP molding, The molded article comprises at least xonotlite-based calcium silicate, an acrylic resin, and inorganic fibrous particles. In the aforementioned molded body, The content ratio of the aforementioned xonotlite-based calcium silicate is 50 to 80% by mass. The content ratio of the aforementioned acrylic resin is 6 to 15% by mass. A mold material for CFRP molding, wherein the inorganic fibrous particle content is 10 to 30% by mass. Section 2 The CFRP molding material according to item 1, wherein the inorganic fibrous particles include wollastonite. Section 3 The molded body contains 1 to 10% by mass of reinforcing fibers, as described in item 1 or 2. [Effects of the Invention]

[0009] The CFRP molding material of the present invention has excellent dimensional stability and high tensile strength, making it suitable as a molding material for CFRP. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described in detail below. In this specification, the expressions "containing" and "including" include the concepts of "containing," "including," "substantially consisting of," and "consisting only of."

[0011] The CFRP molding material of the present invention comprises a molded article containing at least xonotlite-based calcium silicate, an acrylic resin, and inorganic fibrous particles. In the molded article, the content of xonotlite-based calcium silicate is 50 to 80% by mass, the content of the acrylic resin is 6 to 15% by mass, and the content of the inorganic fibrous particles is 10 to 30% by mass.

[0012] The CFRP molding material of the present invention (hereinafter abbreviated as "the molding material of the present invention") has excellent dimensional stability and high tensile strength. Therefore, the molding material of the present invention can be suitably used as a molding material for molding CFRP.

[0013] As described above, the mold material of the present invention comprises a molded article containing at least xonotlite-based calcium silicate, an acrylic resin, and inorganic fibrous particles in predetermined proportions.

[0014] The type of xonotlite-based calcium silicate included in the molded article is not particularly limited, and for example, known xonotlite-based calcium silicate can be broadly applied. Examples of xonotlite-based calcium silicate included in the molded article include calcium silicate produced by the reaction of a calcareous raw material and a siliceous raw material. In this case, for example, the xonotlite-based calcium silicate may be in the form of a hydrate.

[0015] The calcareous raw material can broadly include known calcareous raw materials used for producing, for example, wollastonite-based calcium silicate. Specifically, slaked lime, quicklime, etc. can be mentioned. Further, the siliceous raw material can broadly include known siliceous raw materials used for producing, for example, wollastonite-based calcium silicate. For example, silica powder, diatomaceous earth, silica fume, etc. can be mentioned.

[0016] In wollastonite-based calcium silicate, the value of CaO / SiO2 representing the molar ratio of CaO and SiO2 is not particularly limited and can be, for example, in the range of 0.90 to 1.40.

[0017] The type of acrylic resin contained in the molded body is not particularly limited. The acrylic resin contained in the molded body is preferably derived from a latex containing acrylic resin particles. In this case, the dimensional stability and tensile strength of the shaped material are likely to be improved. Therefore, the acrylic resin contained in the molded body is preferably in particulate form. In this case, the average particle diameter of the acrylic resin particles is preferably, for example, 10 to 1000 nm, and more preferably 50 to 500 nm. The average particle diameter can be measured, for example, by the dynamic light scattering method.

[0018] Examples of the type of acrylic resin can include polymers of (meth)acrylic acid esters. In this case, the dimensional stability and tensile strength of the shaped material are likely to be improved. In this specification, “(meth)acrylic” means “acrylic” or “methacrylic”.

[0019] (Meta)acrylic acid ester polymers may be homopolymers or copolymers. Examples of (meta)acrylic acid esters include methyl (meta)acrylate, ethyl (meta)acrylate, propyl (meta)acrylate, n-butyl (meta)acrylate, i-butyl (meta)acrylate, t-butyl (meta)acrylate, hexyl (meta)acrylate, etc. The polymer of (meta)acrylic acid ester may also contain monomer units other than (meta)acrylic acid ester, such as (meta)acrylic acid, styrene, etc. When the acrylic resin is a copolymer of a (meta)acrylic acid ester polymer, it is preferably an acrylic styrene polymer.

[0020] The acrylic latex used for containing the acrylic resin in the molded body can be produced by, for example, known methods or can also be obtained from commercial products, etc. Examples of commercial products of acrylic latex include "Ultrazol PJ-100" (average particle diameter 80 - 140 nm) and "Ultrazol JAC-100" (average particle diameter 150 - 200 nm) of Marubishi Yuka Kogyo Co., Ltd., "Vinibran VB" (average particle diameter 160 nm or less) and "Vinibran HS-832" (average particle diameter about 330 nm) of Nisshin Chemical Industry Co., Ltd., etc.

[0021] The molded body can contain only one kind of acrylic resin or can also contain two or more kinds.

[0022] The type of inorganic fibrous particles contained in the molded body is not particularly limited, and for example, the inorganic fibrous particles contained in conventional calcium silicate molded bodies can be widely applied.

[0023] Examples of inorganic fibrous particles include wollastonite, calcium carbonate, potassium titanate, etc. Among them, in terms of easily improving the dimensional stability and tensile strength of the profile, it is preferable that the inorganic fibrous particles contain wollastonite. The inorganic fibrous particles contained in the molded body may consist only of wollastonite.

[0024] The fiber length of the inorganic fibrous particles is not particularly limited and can be, for example, 10 to 1000 μm, and preferably 15 to 600 μm.

[0025] The molded article may contain only one type of inorganic fibrous particle, or it may contain two or more types.

[0026] As described above, the molded article contains 50 to 80% by mass (i.e., 50% or more and 80% or less by mass) of xonotlite-based calcium silicate relative to the total mass of the molded article. If the content of xonotlite-based calcium silicate is less than 50% by mass, the strength of the molded article decreases, and a mold material with the desired tensile strength cannot be obtained. If the content of xonotlite-based calcium silicate exceeds 80% by mass, the strength of the molded article decreases, the dimensional change rate also increases, and a mold material with the desired tensile strength and dimensional change rate cannot be obtained.

[0027] The molded article preferably contains 53% by mass or more of the xonotlite-based calcium silicate relative to the total mass of the molded article, more preferably 55% by mass or more, and even more preferably 60% by mass or more. Furthermore, the molded article preferably contains 75% by mass or less of the xonotlite-based calcium silicate relative to the total mass of the molded article.

[0028] As described above, the molded article contains 6 to 15% by mass of the acrylic resin (i.e., 6% or more and 15% or less by mass). If the content of the acrylic resin is less than 6% by mass, the strength of the molded article decreases, and a mold material with the desired tensile strength cannot be obtained. If the content of the acrylic resin exceeds 15% by mass, the strength of the molded article decreases, the dimensional change rate also increases, and a mold material with the desired tensile strength and dimensional change rate cannot be obtained.

[0029] The molded article preferably contains 8% by mass or more of the acrylic resin relative to the total mass of the molded article. More preferably, the molded article contains 12% by mass or less of the acrylic resin relative to the total mass of the molded article, and even more preferably 10% by mass or less.

[0030] As described above, the molded article contains 10 to 30% by mass (i.e., 10% or more and 30% or less by mass) of the inorganic fibrous particles. If the content of the inorganic fibrous particles is less than 10% by mass, the dimensional change rate of the molded article increases, and a mold material with the desired dimensional change rate cannot be obtained. If the content of the inorganic fibrous particles exceeds 30% by mass, the strength of the molded article decreases, and a mold material with the desired tensile strength cannot be obtained.

[0031] The molded article preferably contains 15% by mass or more of the inorganic fibrous particles relative to the total mass of the molded article. More preferably, the molded article contains 25% by mass or less of the inorganic fibrous particles relative to the total mass of the molded article.

[0032] The molded article may contain materials other than xonotlite-based calcium silicate, acrylic resin, and inorganic fibrous particles. For example, the molded article may contain reinforcing fibers. In this case, the strength of the molded material can be improved.

[0033] The reinforcing fibers are other than the inorganic fibrous particles mentioned above, and can broadly include, for example, fibrous materials contained in conventional calcium silicate molded bodies, such as various organic fibers and glass fibers. Examples of organic fibers include cellulose fibers and carbon fibers.

[0034] When a molded article contains reinforcing fibers, the proportion of such fibers is not particularly limited. For example, when a molded article contains reinforcing fibers, it is preferable that the molded article contains 1 to 10% by mass (i.e., 1% or more by mass and 10% or less by mass) of the reinforcing fibers. In this case, the molded article has sufficient strength, making it easier to obtain a mold material with the desired tensile strength, and also making it easier to suppress fuzzing on the surface of the mold material and improve its smoothness.

[0035] The molded article may also contain a wide range of additives found in conventional calcium silicate molded articles, such as cement, resin (excluding the aforementioned acrylic resin), infrared shielding material, pigment, dye, water repellent, surfactant, flocculant, dispersant, and lubricant. Furthermore, the molded article may also contain various types of calcium silicate other than xonotlite-based calcium silicate.

[0036] The molded article preferably contains xonotlite-based calcium silicate, acrylic resin, inorganic fibrous particles, and reinforcing fibers. This allows the mold material of the present invention to have a smaller rate of dimensional change and higher tensile strength (interlaminar strength).

[0037] The mold material of the present invention may be formed in combination with other members, as long as it comprises the molded body, or the mold material of the present invention may be formed solely from the molded body.

[0038] The shape of the mold material of the present invention is not particularly limited and can be made into an appropriate shape depending on the shape of the CFRP, its application, etc. For example, it can be made into a shape and size similar to known mold materials for CFRP molding. For example, the bulk density of the mold material is 0.5 to 0.6 g / cm³. 3 This allows the mold material to have sufficient strength and excellent workability.

[0039] The method for manufacturing the mold material of the present invention is not particularly limited, and for example, known methods for manufacturing mold materials for CFRP molding can be widely employed. For example, the mold material of the present invention can be obtained by a manufacturing method that includes a step of molding a raw material slurry to obtain the molded body. This manufacturing method will be described below as an example.

[0040] The raw material slurry contains, for example, xonotlite-based calcium silicate, latex containing acrylic resin, inorganic fibrous particles, and water. Such raw material slurry may optionally contain reinforcing fibers and various additives such as cement.

[0041] The method for preparing the raw material slurry is not particularly limited. For example, the raw material slurry can be obtained by preparing an aqueous slurry by hydrothermally reacting the raw materials for producing xonotlite-based calcium silicate in water, and then adding an acrylic resin, inorganic fibrous particles, and, if necessary, various additives such as reinforcing fibers and cement to this aqueous slurry. The raw materials for producing xonotlite-based calcium silicate are, for example, the calcareous raw material and the siliceous raw material. The hydrothermal reaction can cause a reaction between the calcareous raw material and the siliceous raw material to produce xonotlite-based calcium silicate. The produced xonotlite-based calcium silicate is, for example, in the form of secondary particles. In addition to xonotlite-based calcium silicate, the aqueous slurry may also contain a small amount of tobermorite. The conditions for the hydrothermal reaction are not particularly limited and can be, for example, the same as those for a known hydrothermal reaction to obtain a molded article mainly composed of xonotlite-based calcium silicate.

[0042] In the raw material slurry, the proportion of each raw material can be appropriately adjusted so that the proportion of xonotlite-based calcium silicate, acrylic resin, and inorganic fibrous particles in the resulting molded article falls within a desired range. Furthermore, the amount of water in the raw material slurry can be adjusted, for example, so that the solid content concentration is 5 to 15% by mass.

[0043] A molded body can be obtained by dewatering and press-molding the raw material slurry. Specifically, the raw material slurry is poured into a mold, dewatering and press-molding is performed at a predetermined press pressure to form a raw plate, and then the raw plate is dried to obtain the molded body.

[0044] In the aforementioned dewatering press molding, the press pressure is, for example, 50 to 150 kg / cm². 2 This can be done. The conditions for drying the raw board are not particularly limited; for example, the raw board can be dried by heating it in a dryer. The drying temperature is not particularly limited and can be adjusted as appropriate depending on the composition, purpose, and application of the molded body.

[0045] As described above, the molded body is obtained by molding and drying the raw material slurry, and the mold material of the present invention can be obtained by combining such molded body with other components as needed.

[0046] The mold material of the present invention, by comprising the molded body, is less prone to dimensional changes even if moisture absorption occurs during storage, for example, and exhibits excellent dimensional stability. Furthermore, since the mold material of the present invention has high tensile strength, when molding CFRP using such a mold material and demolding the CFRP, mold damage is less likely to occur. Therefore, the mold material of the present invention can be suitably used as a mold material for molding CFRP. [Examples]

[0047] The present invention will be described more specifically below with reference to examples, but the present invention is not limited to the embodiments of these examples.

[0048] (raw materials) The raw materials used in the examples and comparative examples are as follows: • Calcareous raw materials: Quicklime (CaO content of 93% or more by weight) • Silicate raw material: Silica (SiO2 content of 95% or more by mass) • Wollastonite: Tomoe Industries Co., Ltd. "WFA-80" (fiber length 505 μm) • Cement: White cement (Taiheiyo Cement Corporation) • Acrylic resin (latex): Ultrazol PJ-500 (Marubishi Oil & Chemical Industry Co., Ltd.) • SBR resin (latex): Crosslen CMX-110 (Aica Kogyo Co., Ltd.) • Organic fiber: "SWP E-400" manufactured by Mitsui Chemicals, Inc. • Glass fiber: Nippon Electric Glass Co., Ltd. "ACS 13S-750 (length 13mm)" • Coagulant: ADEKA "Adelite CT-100"

[0049] (Example 1) The raw materials were selected to achieve the molded body composition (mass%) shown in Table 1, and a molded body was obtained as follows. First, 48 parts by mass of quicklime, 52 parts by mass of silica, and 1200 parts by mass of water were mixed to prepare a raw material slurry, and this raw material slurry was heated in an autoclave at 1.47 MPa (15 kgf / cm²). 2 A hydrothermal reaction was carried out under conditions of 197°C for 4 hours with stirring. This hydrothermal reaction yielded an aqueous slurry containing secondary particles mixed with xonotlite (CaO / SiO2 ratio 0.99) and a small amount of tobermorite. 73 parts by mass of the above aqueous slurry was prepared in terms of solid content. To this aqueous slurry, 10 parts by mass of wollastonite, 1 part by mass of cement, 10 parts by mass of acrylic resin (latex), 3 parts by mass of organic fiber, and 3 parts by mass of glass fiber were added, and 0.1 parts by mass of flocculant was added on the outside to obtain the raw material slurry. After pouring this raw material slurry into the mold, it was subjected to a pressure of 100 kgf / cm². 2 The material was dehydrated under pressure, and the resulting dehydrated molded body was dried in an atmosphere at 130°C to obtain a molded body. The surface of this molded body was polished, and it was cut to a predetermined size.

[0050] (Examples 2-3, Comparative Examples 1-4) A molded article was obtained in the same manner as in Example 1, except that the raw materials were selected to have the molded article composition (mass%) shown in Table 1.

[0051] (Evaluation method) The moisture absorption rate, moisture absorption dimensional change rate, and interlayer strength of the molded articles obtained in each example and comparative example were evaluated using the following procedure.

[0052] <Moisture absorption rate> The moisture absorption rate was determined by drying a 300 x 100 mm (50 mm thick) molded body to a constant weight at 105°C, then curing it for 72 hours at 23°C and 50% humidity using ESPEC's "Platins J PR-3J," and measuring the mass increase rate before and after curing.

[0053] <Moisture absorption dimensional change rate> The dimensional change rate due to moisture absorption was calculated by drying a 300 x 100 mm (50 mm thick) molded body to a constant weight at 105°C, then allowing it to absorb moisture for 72 hours under 23°C and 50% humidity conditions using ESPEC's "Platinus J PR-3J". The dimensional change before and after moisture absorption was measured using a Mitutoyo dial gauge 2119S-10, and the dimensional change rate was calculated. This dimensional change rate was then evaluated based on the following criteria. <Judgment Criteria (Moisture Absorption Dimensional Change Rate)> ○: The dimensional change rate due to moisture absorption was less than 0.085%. ×: The dimensional change rate due to moisture absorption was 0.085% or higher.

[0054] <Interlaminar strength (tensile strength)> Metal fittings were attached to both sides (40mm x 40mm surface) of a 40 x 40mm (50mm thick) molded body, and the fittings were pulled vertically using a Yonekura Seisakusho "Universal Testing Machine YS-50". The load (N) at which the body broke was measured over the cross-sectional area (mm²). 2 The interlayer strength was defined as the value obtained by dividing by ). <Judgment criteria (interlaminar strength)> ○: Interlaminar strength is 0.9 N / mm 2 That was all. ×: Interlaminar strength is 0.9 N / mm 2 It was less than [amount missing].

[0055] (Evaluation results) Table 1 shows the content ratio of each component in the molded articles for each example and comparative example, as well as various evaluation results (moisture absorption rate, moisture absorption dimensional change rate, interlaminar strength (tensile strength)).

[0056] Table 1 shows that the molded articles obtained in each example had a small rate of dimensional change due to moisture absorption and high interlaminar strength (tensile strength). In contrast, the molded articles obtained in each comparative example had a large rate of dimensional change due to moisture absorption, or even if the rate of dimensional change due to moisture absorption was small, the interlaminar strength (tensile strength) was low.

[0057] Therefore, it was found that the molded articles obtained in each example exhibited excellent dimensional stability and high tensile strength, making them suitable as molding materials for CFRP.

[0058] Table 1

Claims

1. A mold material for CFRP molding, The molded article comprises at least xonotlite-based calcium silicate, an acrylic resin, and inorganic fibrous particles. The aforementioned acrylic resin is an acrylic styrene polymer. In the aforementioned molded body, The content ratio of the aforementioned xonotlite-based calcium silicate is 50 to 80% by mass. The content ratio of the acrylic resin is 6 to 15% by mass. A mold material for CFRP molding, wherein the inorganic fibrous particle content is 10 to 30% by mass.

2. The CFRP molding material according to claim 1, wherein the inorganic fibrous particles include wollastonite.

3. The molded body contains 1 to 10% by mass of reinforcing fibers, as described in claim 1 or 2.

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