TW202237711A - Fiber reinforced plastic molding material and molded body thereof - Google Patents

Abstract

An object of the present invention is to provide a fiber reinforced plastic molding material capable of suppressing spring back even when a molded product is used near a processing temperature, without using a super engineering plastic which is difficult to process.

As a solution, the present invention provides a thermoplastic resin composition containing a thermoplastic resin, which becomes a matrix resin of a fiber reinforced plastic after it has been impregnated in a reinforcing fiber base material. 50 wt.% or more of the entire resin composition is a thermoplastic resin having phenoxy resin as an essential component, and when the temperature is raised to 280℃ from room temperature and lowered to room temperature again by using a rheometer, the melt viscosity exceeds 10,000 Pa．s in the temperature range of 220℃ or lower.

Description

Fiber-reinforced plastic molding material and its molded body

The present invention relates to a fiber-reinforced plastic molding material and a molded article thereof. The fiber-reinforced plastic molding material can obtain a fiber-reinforced plastic molded product that suppresses springback even when placed in a high-temperature environment and has excellent heat resistance.

Compared with fiber-reinforced plastics (FRP) that use thermosetting resins as matrix resins such as epoxy resins, thermoplastic fiber-reinforced plastics (FRTP) that use thermoplastic resins as matrix resins are highly productive and recyclable materials. Therefore, its practical technology was developed.

However, when using CFRTP, especially the non-woven fabric obtained from short-fiber carbon fiber papermaking as the reinforcing fiber base material, when forming by hot pressing, in the softened state of the matrix resin during the preheating step or demoulding after forming, The volume expansion of the reinforcing fiber base material due to the recovery force causes problems such as decomposition of the resin, deterioration of the surface properties of the molded article, and generation of voids in the molded article. In addition, in actual use, if the surrounding temperature is close to the molding processing temperature, the restoring force of the reinforcing fiber base material cannot be suppressed, and there is a problem that the molded body undergoes a predetermined or more dimensional change.

The recovery force of the above-mentioned reinforced fiber substrate is also called rebound. In order to reduce the rebound, the following method has been developed: a super engineering plastic with a glass transition temperature (Tg) or a very high melting point is used as the matrix tree A method of adjusting the blending ratio of resin and reinforcing fiber (Patent Document 1); a method of using a thermoplastic resin whose storage modulus is above a fixed value as measured by dynamic viscoelasticity at 200°C as a matrix resin (Patent Document 2 ); and a method of blending carbon black or the like into a thermoplastic resin to become a matrix resin to increase the strength of the resin (Patent Document 3).

[Prior Art Literature]

[Patent Document]

Patent Document 1: Japanese Patent Laid-Open No. 2016-190955.

Patent Document 2: Japanese Patent Laid-Open No. 2014-95034.

Patent Document 3: WO2015/016252.

However, the use of super engineering plastics with a very high Tg or melting point requires very high temperature (about 300°C) processing, and there are technical difficulties in the manufacture of FRTP. Also, in the method of increasing the modulus of elasticity of the resin at high temperature, the modulus of elasticity decreases in an environment exceeding the Tg or melting point of the thermoplastic resin used for the matrix resin, so there is a problem that the springback suppression effect is insufficient.

Therefore, the object of the present invention is to provide a resin composition that can obtain a molded product even when using a molded product near the processing temperature without using a super engineering plastic that is difficult to process. FRTP that can inhibit rebound.

The inventors of the present invention have found that when forming a fiber-reinforced plastic molding material in which a fiber-reinforced base material is impregnated with a resin composition containing a thermoplastic resin, the fiber-reinforced plastic composition The melt viscosity of the forming material becomes 10000Pa in the temperature region below 220℃ for the matrix resin composition. s or more, by using such a resin composition, it is possible to provide a molded article with both excellent heat resistance and dimensional stability, thereby completing the present invention.

The present invention is a thermoplastic resin composition comprising a thermoplastic resin, the thermoplastic resin composition becomes a matrix resin of fiber-reinforced plastic after being impregnated in a reinforced fiber base material,

More than 50 wt% of the entire resin composition is a thermoplastic resin containing phenoxy resin as an essential component,

When using a rheometer to heat up from room temperature to 280°C and then cool down to room temperature, the melt viscosity exceeds 10000Pa in the temperature range below 220°C. the s

The matrix resin is preferably a mixture of the phenoxy resin (A) and the second thermoplastic resin (B-1 to 3), 30wt% to 70wt% of the matrix resin is the phenoxy resin (A), and the rest is the second thermoplastic resin. 2. Thermoplastic resins (B-1 to 3). The second thermoplastic resins (B-1 to 3) are at least one selected from the group consisting of polyamide resins, polycarbonate resins, and polyester resins.

Moreover, a preferable matrix resin contains a thermoplastic resin and an epoxy resin (C).

Also, it is preferable that the resin composition used as the matrix resin exhibit mutual reactivity or crosslinkability.

The present invention is a fiber-reinforced plastic molding material obtained by impregnating the above-mentioned resin composition into a reinforcing fiber base material, and a molded article obtained by molding the above-mentioned fiber-reinforced plastic molding material.

The molded article of the present invention is preferably placed in a hot environment at the same temperature as the molding process for 10 minutes, and then cooled to room temperature, and the thickness change rate of the fiber-reinforced plastic is more than 0% and less than 10%.

Fiber-reinforced plastics using the resin composition of the present invention as a matrix resin, after molding, even if placed in an environment above the molding temperature, the softening of the matrix resin is very small, and the rebound of the reinforcing fibers can be suppressed, so in high-temperature environments The retention rate of the mechanical strength is high, and the deformation of the molded product is not easy to occur. Therefore, it can be used as FRTP materials for structural members used in harsh environments such as automobiles and aerospace, especially as CFRTP materials.

In addition, the matrix resin is made of general-purpose resin materials that are not super engineering plastics, so the cost is relatively low in terms of materials or manufacturing.

The present invention will be described in detail below.

The matrix resin composition used in the fiber-reinforced plastic molding material of the present invention contains a thermoplastic resin. Matrix resin is also called MT resin.

The thermoplastic resin can be, for example, polyolefins such as phenoxy resin (also known as thermoplastic epoxy resin), polyamide resin, polyester resin, polycarbonate resin, polypropylene resin modified with acid anhydride, and the like. It is especially preferable to use a phenoxy resin, which has good affinity and impregnation with the reinforcing fiber substrate, epoxy groups remain at the end of the molecular chain, and secondary hydroxyl groups in the side chains are easily utilized for crosslinking reactions.

The matrix resin can be combined with thermoplastic resin and thermosetting resin including epoxy resin, but relative to the total weight of the matrix resin, the amount of thermoplastic resin is more than 50wt%, preferably 60-100wt%, more preferably 75-100wt%. Also, if the thermoplastic resin in the matrix resin is less than 50 wt%, the influence of the thermosetting resin is strong, so the molding processing time of the fiber-reinforced plastic molding material becomes longer, or the toughness or recyclability of the molded product decreases.

The fiber-reinforced plastic molding material of the present invention uses a rheometer to increase the temperature from room temperature to 280°C and then cool down to room temperature, and measure the melt viscosity of the matrix resin (resin composition) in the temperature range below 220°C to exceed 10,000Pa. s. The melt viscosity of the matrix resin is preferably 12000Pa. s or more, more preferably 15000Pa. s or more. If the melt viscosity of the matrix resin is less than 10,000, when the molded article is exposed to a high temperature environment, the matrix resin will soften excessively and flow against the repulsive force of the reinforcing fiber base material, resulting in a rebound phenomenon.

Also, in the present invention, the melt viscosity exceeds 10000Pa. The reason why the temperature of s is in the temperature range of 220° C. or lower is that the formed CFRP has sufficient heat resistance even if it is exposed to an environment of about 200° C. Of course, even if the melt viscosity exceeds 10000Pa above 220°C. s can also obtain the effect of the present invention, but the upper limit is about 280°C.

Also, when measuring the melt viscosity, compare the melt viscosity ( ρ ₂₂₀₊ ) at 220°C when the temperature rises from room temperature to 280°C, and the minimum value of the melt viscosity ( ρ ₂₂₀ ≧) in the temperature range below 220°C when the temperature is lowered. , preferably the melt viscosity ( ρ ₂₂₀ ≧) is greater than the melt viscosity ( ρ ₂₂₀₊ ). In addition, at the glass transition point +100°C or melting point -5°C of the main resin components constituting the matrix resin alone (when the constituents are equal, the resin components with low thermal properties alone), the melting of the matrix resin of the present invention The viscosity ( ρ _Tg+100 , ρ _Tm-5 ) is more preferably higher than the independent melt viscosity of the main resin constituting the aforementioned matrix resin.

As mentioned above, when the temperature of the matrix resin composition is raised or lowered, by making the melt viscosity parameter satisfy the aforementioned relationship, the fiber-reinforced plastic molding obtained from the fiber-reinforced plastic molding material of the present invention can be placed at a high temperature of 200°C In the environment, for example, even if the matrix resin softens, its fluidity is greatly suppressed, so springback is less likely to occur, and the dimensional accuracy and mechanical properties of fiber-reinforced plastic moldings can be further maintained.

On the other hand, the minimum melt viscosity of the matrix resin composition used in the fiber-reinforced plastic molding material of the present invention is 3000Pa when the temperature rises from room temperature to 280°C. s or less is suitable for satisfactorily impregnating the reinforcing fiber base material with the matrix resin during molding. The minimum melt viscosity is preferably 50 to 3000Pa. s, more preferably 100 to 2500Pa. s.

The matrix resin is not particularly limited as long as it contains a thermoplastic resin and exhibits the above-mentioned specific melt viscosity behavior, but is preferably a mixture of two or more resins that are mutually reactive, and more preferably a mixture of two or more resins that are crosslinkable.

In addition, the temperature of the resin composition was raised to 280° C. with a rheometer, and then directly kept at 280° C. for more than 30 minutes. The reactivity of the matrix resin composition was judged by whether the melt viscosity increased at this time.

It is preferable to exhibit a reactivity in which a melt viscosity increase (Δρ) of 2 times or more can be confirmed during the period of holding at 280°C. More preferably, it is a reactivity that can confirm a melt viscosity increase of 5 times or more.

A mixture of two or more resins that are reactive with each other is a resin composition in which the residual reactive groups at the end of the polymer chain react, for example, a combination of a phenoxy resin and a polyamide resin.

Phenoxy resin (A) and polyamide resin (B) are all resins with polar groups. In the end of the polymer chain, phenoxy resin (A) has residual epoxy groups, and polyamide resin (B-1 ) has a residual amine or carboxyl group, and if the two are mixed, the compatibility will be good, so the two will react to a certain extent.

The compounding ratio of the phenoxy resin (A) to any one of the second thermoplastic resin (B) selected from the group consisting of polyamide resin, polycarbonate resin and aromatic polyester resin is based on the ratio of both When the total is 100% by mass, the ratio of the phenoxy resin (A) may be 30 to 70% by mass, and the ratio of the second thermoplastic resin (B) may be 30 to 70% by mass. That is, the blending ratio (mass ratio) shown in (A)/(B) can be blended at a ratio of 30/70 to 70/30. The blending ratio (A)/(B) is preferably 70/30 to 40/60, more preferably 70/30 to 50/50. If the blending ratio (A)/(B) exceeds 70/30, the ratio of the phenoxy resin (A) will be further increased, and the second thermoplastic resin will be blended The effect of improving the heat resistance of the fat will disappear. Also, when the compounding ratio (A)/(B) is less than 30/70, and the ratio of the second thermoplastic resin (B) becomes high, the increase in rigidity of the compounded phenoxy resin will disappear, so the high temperature environment will lower rigidity.

Phenoxy resin is a thermoplastic resin obtained by the condensation reaction of divalent phenolic compound and epihalohydrin, or the complex addition reaction of divalent phenolic compound and bifunctional epoxy resin, which can be used in solution or without solvent Obtained by known methods in the past. Also, resins called polyhydroxypolyether resins and thermoplastic epoxy resins are another names for phenoxy resins, and are equivalent to the phenoxy resins of the present invention.

The average molecular weight of the phenoxy resin is generally 10,000 to 200,000, preferably 20,000 to 100,000, more preferably 30,000 to 80,000 as the mass average molecular weight (Mw). If the Mw is too low, the strength of the FRTP molded body will be poor, and if the Mw is too high, the workability or processability will be poor. In addition, Mw is the value converted using the standard polystyrene calibration curve measured by gel permeation chromatography (GPC).

The hydroxyl equivalent (g/eq) of the phenoxy resin is usually 50 to 1000, preferably 50 to 750, particularly preferably 50 to 500. If the hydroxyl equivalent is too low, the number of hydroxyl groups will increase and the water absorption will increase, which may lower the mechanical properties. If the hydroxyl equivalent is too high, the number of hydroxyl groups will be low, so the wettability with the reinforcing fiber substrate, especially with carbon fibers will decrease.

The glass transition point (Tg) of the phenoxy resin is suitably 65°C to 160°C, preferably 70°C to 150°C. If the glass transition point is lower than 65°C, the formability will be better, but there will be problems such as deterioration of the storage stability of the powder or ingot due to agglomeration, or a sticky feeling (deterioration of viscosity) during preforming. If it is higher than 160°C, the melt viscosity will increase, and the formability and the filling property of the reinforcing fiber base material will be poor, and as a result, press molding at a higher temperature will be required. In addition, the glass transition point of the phenoxy resin is measured in the range of 20 to 280°C using a differential scanning thermal analyzer at a temperature increase of 10°C/min, and is a value obtained from the peak value of the second scan.

The melt viscosity of phenoxy resin is preferably 3,000Pa in the temperature region above Tg (to 160°C). s or less, more preferably 500Pa. s or less, and more preferably 300Pa. below s. On the other hand, the lower limit of melt viscosity is preferably 10Pa. s or more, more preferably 50Pa. s or more. In addition, phenoxy resins do not have a melting point (Tm), so the melt viscosity changes moderately with temperature.

The phenoxy resin is not particularly limited as long as it satisfies the above-mentioned specific physical properties, and examples thereof include: bisphenol A type phenoxy resin (such as manufactured by NIPPON STEEL Chemical & Material Co., trade names Phenotote YP-50, YP-50S, YP- 55U), bisphenol F type phenoxy resin (such as NIPPON STEEL Chemical & Material company, trade name Phenotote FX-316), bisphenol A and bisphenol F copolymerization type phenoxy resin (such as NIPPON STEEL Chemical & Material Co., Ltd., brand name YP-70), or special phenoxy resin (for example, NIPPON STEEL Chemical & Material company, brand name Phenotote YPB-43C, FX293), etc., these can be used alone or in combination of two or more.

The second thermoplastic resin (B) is any one selected from the group consisting of polyamide resin (B-1), polycarbonate resin (B-2) and polyester resin (B-3). is a mixture of such.

Polyamide resin is a thermoplastic resin whose main chain is composed of repeated amide bonds. It can be formed by ring-opening polymerization of lactamides or co-condensation of lactamides, dehydration condensation of diamines and dicarboxylic acids, etc. And get.

Polyamide resins are: full aliphatic polyamide resin (also called nylon) whose main chain is composed of aliphatic skeleton (such as nylon 6, nylon 11, nylon 12, nylon 66, nylon 610, etc.), the main chain contains aromatic semi-aliphatic polyamide resin or semi-aromatic polyamide resin (such as nylon 6I, nylon 6T, nylon 9T, nylon M5T, nylon MXD6, etc.), and A fully aromatic polyamide resin (also known as polyaramid) whose main chain consists only of an aromatic backbone [Kevlar, Nomex (manufactured by TORAY DuPont Co., Ltd.), Twaron, Conex (manufactured by Teijin Co., Ltd.)]. All of these can be used in the present invention, but it is preferred to use Fully aliphatic polyamide resin and/or semi-aliphatic (semi-aromatic) polyamide resin, more preferably fully aliphatic polyamide resin, most preferably obtained by ring-opening polymerization of ε-caprolactam Fully aliphatic polyamide resin (also known as nylon 6 (polyamide 6)).

The melting point or glass transition point of the polyamide resin is above 180°C and the melt viscosity at a temperature above 250°C is preferably 1,000Pa. below s. It is preferable to use a melting point or a glass transition point of 200 ° C or more, and a melt viscosity of 1000 Pa at 200 to 350 ° C. s or less.

The weight average molecular weight (Mw) of the polyamide resin is preferably at least 10,000, more preferably at least 25,000. By using a polyamide resin having a Mw of 10,000 or more, good mechanical strength of the molded article can be secured.

The polycarbonate resin (B-2) blended with the phenoxy resin (A) is a thermoplastic resin obtained by reacting a dihydroxy compound with phosgene or a carbonic acid diester.

The polycarbonate resin preferably used in the present invention is solid at room temperature, and preferably has a melt viscosity of 3,000Pa at 280°C. s or less, more preferably 2,000Pa. s or less, and more preferably 1,500Pa. below s. If the melt viscosity exceeds 3,000Pa. s, the fluidity of the resin during molding processing will be reduced, and the resin will not be able to fully expand and cause voids, so it is not good.

Among the polycarbonate resins, an aromatic polycarbonate resin obtained from an aromatic dihydroxy compound as a raw material is preferable in consideration of compatibility with bifunctional epoxy resins or phenoxy resins. Aromatic dihydroxy compounds can be exemplified by 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane alkane, 2,2-bis(4-hydroxyphenyl)butane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether, Bis(4-hydroxyphenyl)phenylmethane, 2,2-bis(4-hydroxyphenyl-3-methylphenyl)propane, 1,1-bis(4-hydroxy-3-tert-butylbenzene base) propane, 1,1-bis(4-hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 4,4'-dihydroxydiphenylsulfone, 4, 4'-dihydroxy-3,3'-dimethyldiphenylsulfone, 4,4'-dihydroxydiphenylsulfide, 4,4'-dihydroxydiphenylene, 4,4'-dihydroxy-3,3'-dimethyldiphenylene, 2, 2-bis(4-hydroxy-3-bromophenyl)propane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, 2,2-bis(4-hydroxy-3,5 -dichlorophenyl)propane and the like. These can be used individually or in mixture of 2 or more types.

The weight average molecular weight (Mw) of the polycarbonate resin is not particularly limited, but it is preferably in the range of 10,000 to 250,000, more preferably in the range of 15,000 to 200,000, from the viewpoint of securing the mechanical strength of the molded article. If the Mw of the polycarbonate resin is too low, the mechanical properties and heat resistance of the molded article may be poor, and if the Mw is too high, the handleability and processability are likely to be poor. In addition, Mw is a value measured with a gel permeation chromatography and converted using a standard polystyrene calibration curve.

The glass transition temperature (Tg) of the polycarbonate resin may be 200°C or lower. Preferably it is 140°C to 170°C, more preferably 145°C to 165°C. If the Tg of the polycarbonate resin is higher than 200°C, the melt viscosity will increase. When the resin composition of this embodiment is applied to FRP, for example, it is difficult to impregnate the reinforcing fiber substrate without defects such as voids. On the other hand, the lower limit of Tg is not particularly limited as long as there is no problem with workability, and may be approximately 140° C. or higher.

Regarding the melting point (Tm) of polycarbonate resin, although there is no obvious Tm, it can be in the range of 200 to 300°C, preferably 220 to 280°C, more preferably 240 to 260°C. If the melting point is less than 200°C, for example, when it is applied to FRP, the crosslinking reaction may start in the state of insufficient impregnation of the reinforcing fiber base material of phenoxy resin. Forming machine with high temperature specification.

The polyester resin (B-3) suitable for the present invention is an aromatic polyester resin obtained by polycondensation of a dicarboxylic acid compound and a diol with a melting point of 200° C. or higher, or a semi-aromatic polyester resin.

Examples of aromatic polyester resins that use polycondensates of dicarboxylic acid compounds and diols as structural units include polyethylene terephthalate, polyethylene naphthalate, and polytrimethylene terephthalate. ester, polybutylene terephthalate, polytrimethylene isophthalate, polybutylene isophthalate, polynaphthalene Butylene formate, polycyclohexane dimethylene terephthalate, etc. Copolymers include, for example: polytrimethylene isophthalate/terephthalate, polybutylene isophthalate/ Aromatic polyester resins such as terephthalate, polytrimethylene terephthalate/naphthalate, polybutylene terephthalate/naphthalene, etc., but to improve mechanical properties and From the viewpoint of heat resistance, in the present invention, a polycondensate of an aromatic dicarboxylic acid compound and an aliphatic diol is preferred as a polymer or a copolymer as a main structural unit, and a polymer selected from terephthalic acid and A polycondensate of a dicarboxylic acid compound of naphthalene dicarboxylic acid and an aliphatic diol selected from ethylene glycol, propylene glycol, and 1,4-butanediol as the main structural unit of polyethylene terephthalate, polyethylene naphthalate Ethylene Formate, Polytrimethylene Terephthalate, Polybutylene Terephthalate, Polyethylene Isophthalate/Terephthalate, Polytrimethylene Isophthalate/Terephthalate Dicarboxylate, polybutylene isophthalate/terephthalate, polybutylene terephthalate/decane dicarboxylate, polybutylene terephthalate/polytetramethylene Aromatic polyester resins such as diol, preferably polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate or polybutylene naphthalate.

From the viewpoint of improving mechanical properties, the weight average molecular weight (Mw) of the polyester resin is preferably 8,000 or more. In addition, when the weight average molecular weight (Mw) is 500,000 or less, the balance between mechanical properties and moldability is excellent, which is preferable. The weight average molecular weight is more preferably at most 300,000, more preferably at most 250,000.

The melting point or glass transition point of the polyester resin is above 200°C, preferably below 200 to 300°C, more preferably between 220 to 260°C. The higher the melting point, the easier it is to improve heat resistance or strength/rigidity. However, if the melting point is too high, high temperature is required for melting, thermal deterioration is likely to occur during molding, or the viscosity during melting becomes high, reducing fluidity.

At a temperature above the melting point, the melt viscosity is preferably 100 to 2000Pa. s range. By using an aromatic polyester resin having a melt viscosity within this range at a temperature above the melting point, the continuous fiber sheet can be appropriately impregnated with the resin composition when performing molding processing of fiber-reinforced plastic molding materials.

A mixture of cross-linkable resins is a resin composition that can exhibit a three-dimensional cross-linked structure mainly by utilizing the reactive functional groups of the side chains of the polymer chain, regardless of the presence or absence of a cross-linking agent. Examples of such resin compositions include: phenoxy resin (A), epoxy resin (C) and acid anhydride (D), phenoxy resin (A) and polycarbonate resin (B-2) A composition composed of, or a composition composed of a phenoxy resin (A) and a polyester resin (B-3).

In the case of a composition composed of phenoxy resin (A), epoxy resin (C) and crosslinking agent (D),

The phenoxy resin (A) can form a three-dimensional cross-linked structure by utilizing the secondary hydroxyl group in the side chain, and known acid anhydrides, isocyanate compounds, caprolactam, etc. can be used as cross-linking agents.

To achieve the purpose of the present invention, only the phenoxy resin (A) and the crosslinking agent (D) may be used, but the resin composition tends to gel when these are blended, and it is preferable to use the epoxy resin (C) together and a crosslinking agent (D).

Epoxy resin (C) is preferably an epoxy resin with more than 2 functions, such as: bisphenol A epoxy resin (such as Epotohto YD-011, Epotohto YD-7011, Epotohto YD-900), bisphenol F epoxy resin (e.g. Epotohto YDF-2001 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), diphenyl ether type epoxy resin (e.g. YSLV- 80DE), tetramethylbisphenol F-type epoxy resin (such as YSLV-80XY manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), bisphenol sulfide epoxy resin (such as YSLV-80XY manufactured by Nippon Steel & 120TE), hydroquinone epoxy resin (e.g. Epotohto YDC-1312 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), phenolic novolac epoxy resin (such as Nippon Steel & Sumikin Chemical Co., Ltd. Epotohto YDPN-638 made by the company), o-cresol novolak type epoxy resin (such as Epotohto YDCN-701, Epotohto YDCN-702, Epotohto YDCN-703, Epotohto YDCN-704 made by Nippon Steel & Sumikin Chemical Co., Ltd.), aromatic Alkylnaphthalene diol novolak type epoxy resin (such as ESN-355 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), triphenylmethane type epoxy resin (such as EPPN-502H manufactured by Nippon Kayaku Co., Ltd.), etc., However, it is not limited to these, and these can mix and use 2 or more types.

In order to preserve the matrix resin composition as a powder, the epoxy resin (C) is more preferably solid at room temperature, has a melting point of 75°C to 145°C, and a melt viscosity of 1.0Pa at 160°C. Crystalline epoxy resin below s. If it exceeds 1.0Pa. s, the filling ability of the matrix resin composition to the reinforcing fiber base material is poor, and the homogeneity of the molded body obtained is poor, so it is unfavorable.

Also, the melt viscosity of crystalline epoxy resin is much lower than that of solid epoxy resin, so the impregnation of matrix resin can be improved by blending crystalline epoxy resin. Therefore, it is suitable for use with phenoxy resins with high melt viscosity.

The epoxy resin (C) can be blended so as to be 5 to 85 parts by weight with respect to 100 parts by weight of the phenoxy resin (A). Preferably it is 9 to 83 parts by weight, more preferably 10 to 70 parts by weight. If the compounding amount of the epoxy resin (C) exceeds 85 parts by weight, it will take time to harden the epoxy resin, so the required strength for demoulding cannot be obtained in a short time, and the recyclability of FRP will be reduced. On the other hand, if the blending amount of the epoxy resin (C) is less than 5 parts by weight, the effect of blending the epoxy resin cannot be obtained, and it is difficult for the cured product of the matrix resin composition to exhibit a glass transition temperature (Tg) of 160°C or higher. ).

The cross-linking agent (D) is not particularly limited as long as it reacts with the secondary hydroxyl group of the side chain of the phenoxy resin to form a three-dimensional cross-linked structure. It is preferable to use an epoxy resin (C) in combination because the crosslinking reaction proceeds excessively or the crosslinking distance becomes short and the resin composition is likely to be gelled.

Therefore, an acid dianhydride which has reactivity with an epoxy resin (C) and is a polyfunctional body is preferable. In particular, aromatic acid dianhydrides such as pyromelite anhydride or 4,4'-oxydiphthalic anhydride, bisphenol A diphthalic anhydride (BisDA) have many reaction points and can increase the crosslinking density. The Tg of the cross-linked hardened product can be greatly increased, so it is especially good.

The blending amount of the crosslinking agent (D) is usually in the range of 0.6 to 1.3 moles of acid anhydride groups relative to 1 mole of secondary hydroxyl groups of the phenoxy resin (A). It is preferably in the range of 0.9 to 1.3 mol, more preferably in the range of 0.9 to 1.1 mol. If the amount of acid anhydride groups is too small, the reactive acid anhydride groups will be insufficient relative to the secondary hydroxyl groups of the phenoxy resin (A), so the crosslinking density will be low and the rigidity will be poor. A) The secondary hydroxyl group will be excessive, and the unreacted acid anhydride will adversely affect the hardening properties and crosslinking density. Also, considering that there are two forms of crosslinking the phenoxy resin directly through the acid anhydride group (COOH) of the crosslinking agent and crosslinking the phenoxy resin through the epoxy resin, the COOH of the crosslinking agent will be The secondary OH of phenoxy resin and the epoxy group of epoxy resin are consumed, so it is speculated that almost no COOH remains in the hardened product.

If it is a composition composed of phenoxy resin (A), polycarbonate resin (B-2) or aromatic polyester resin (B-3), although they are all thermoplastic resins, by mixing the resin composition Heating to a temperature above 280°C, such as 280 to 320°C, preferably in the range of 280 to 300°C, enables irreversible hardening and thereafter exhibits a characteristic behavior of being almost infusible.

The hardening mechanism at this time is still unclear, but it is speculated that there is a transesterification reaction between the mainly secondary hydroxyl contained in the phenoxy resin and the ester group of the polycarbonate resin or aromatic polyester resin. The epoxy resin chains or phenoxy resin chains are cross-linked with the polycarbonate resin chains to form a three-dimensional network structure and harden.

The matrix resin composition of the fiber-reinforced plastic material of the present invention can be blended with other thermoplastic resins or thermosetting resins, as well as organic solvents, crosslinking agents, inorganic fillers, extender pigments, colorants, Antioxidants, anti-ultraviolet agents, flame retardants, flame retardant additives, etc.

The present invention also includes a fiber-reinforced plastic molding material (hereinafter referred to as "prepreg") in which the resin composition of the present invention is impregnated into a fiber-reinforced substrate to form a matrix resin.

The material of the reinforcing fiber substrate impregnated into the resin composition of the matrix resin composition is not particularly limited, for example, carbon fiber, glass fiber, aramid fiber, alumina fiber, boron fiber, metal fiber, basalt fiber and other inorganic or organic fibers can be used. Fiber, these can be used 1 type or in combination of 2 or more types. Among them, it is preferable to use PAN-based and pitch-based carbon fibers from the viewpoint of high specific strength and specific rigidity and light weight effect.

In addition, the reinforcing fiber can be a unidirectional reinforcing fiber substrate composed of continuous fibers, or a fabric such as plain weave or twill weave, or a non-woven fabric composed of discontinuous reinforcing fibers. Generally, the rebound phenomenon is more obvious when discontinuous reinforcing fibers are used, such as non-woven fabric substrates with short fibers, but when continuous fiber substrates are used to laminate a large number of prepregs and perform press molding, etc. The same springback phenomenon as the material.

The sizing treatment of the reinforcing fiber substrate may be optional. The resin composition of the present invention has good affinity with reinforcing fibers, so even without sizing treatment, the matrix resin and reinforcing fibers can be firmly bonded, but it can be treated with an optimal sizing agent according to the type of resin to be blended. The reinforced fiber base material.

The material for FRP molding of the present invention can be attached or impregnated with a resin composition as a matrix resin on a reinforcing fiber base material by a known method, but in this case, it is preferable to use a method that does not use a solvent.

Such methods include, for example, the following methods: a method of impregnating a film-formed resin composition by melting and impregnating a reinforcing fiber base material composed of continuous fibers (press-in method, film stacking method); continuous fibers spun from a resin composition and reinforcement The method of blending fibers (mixing method); or spreading/coating powdered resin composition on Methods in reinforcing fiber substrates (powder coating method, powder coating method). Among them, the mixing method and the powder coating method are the better methods when the reinforcing fibers are not easily broken when making FRP molding materials, and have flexibility and air permeability. Therefore, even if multiple layers are laminated, FRP molding materials that are less likely to generate internal air bubbles can be obtained. .

In addition, when the reinforcing fibers are short fibers, the following methods can be mentioned: the method of impregnating the resin composition into a powder or molten state as an emulsion in the reinforcing fiber substrate processed into a non-woven state; or mixing the short fibers and the resin composition together. The powder or short fibers are stirred and mixed together, and piled up or assembled to make a prepreg.

In the FRP molding material using the thermoplastic resin composition of the present invention, the adhesion amount of the matrix resin (resin ratio: RC) is 20 to 50% by weight, preferably 25 to 45%, more preferably 25 to 40% . If RC exceeds 50%, the mechanical properties such as tensile and flexural modulus of FRP will decrease. If it is less than 10%, the amount of resin adhesion is very small, so the matrix resin in the base material is not impregnated enough, and there will be thermal and physical properties. There is a risk of degradation of mechanical properties.

The FRP molding material using the thermoplastic resin composition of the present invention can be used alone or in multiple layers, and an FRP molding can be easily produced by heating and pressing. That is, by press molding by hot pressing, shaping and complete impregnation of the reinforcing fiber base material with the matrix resin can be performed simultaneously. As long as the molding using FRP molding materials is heating and press molding, various molding methods such as autoclave molding or hot press molding using molds can be appropriately selected according to the size or shape of the desired FRP molding.

The forming temperature of heating and pressing forming is, for example, 160 to 260°C, preferably 180°C to 250°C, more preferably 180°C to 240°C. If the molding temperature exceeds the upper limit temperature, excess heat will be applied more than necessary, so there is a risk of excess outflow of resin or thermal deterioration. In addition, it takes time to heat up or cool down, so the molding time (takt time) will become longer and the productivity will deteriorate. . On the other hand, if it is lower than the lower limit temperature, the matrix resin The melt viscosity is high, so the impregnation of the matrix resin of the reinforced fiber substrate becomes poor. Forming times can generally be performed for 30 to 60 minutes.

The FRTP molded body obtained from the fiber-reinforced plastic molding material of the present invention will hardly deform even if it is subjected to heat of nearly 300°C, and the rigidity at high temperature is greatly improved. It is also suitable as molded parts for automobiles or industrial machines that require high heat resistance, such as hoods.

[Example]

The present invention will be further specifically described below with examples, but the present invention is not limited to these examples. In addition, the test and measurement methods of various physical properties in Examples and Comparative Examples are as follows.

Average particle size (D50)

The average particle diameter is the particle diameter when the cumulative volume becomes 50% measured on a volume basis with a laser diffraction/scattering type particle size distribution measuring device (microtrac MT3300EX, manufactured by Nikkiso).

Melt viscosity

(measurement of ρ ₂₂₀ ≧, ρ _min )

Using a rheometer (manufactured by Anton Paar Co., Ltd.), the composition for matrix resin (MT resin) processed into a film with four sides of 150 mm and a thickness of 0.4 mm was sandwiched between parallel plates, and the temperature was raised at 5° C./min and then lowered. Under the conditions of frequency 1Hz and load strain 0.2%, various melt viscosities of MT resin were measured when the temperature was raised from room temperature to 280°C and when the temperature was lowered from 280°C to 70°C.

In Table 1, " ρ ₂₂₀ ≧" indicates the minimum value of the melt viscosity in the temperature range below 220°C when the temperature is lowered, and " ρ ( ₂₂₀₊ )" indicates the melting point at 220°C when the temperature is raised from room temperature to 280°C Viscosity, " ρ _min " indicates the minimum value of the melt viscosity when the temperature rises.

(Determination of ρ _Tg+100 and ρ _Tm-5 )

Using a rheometer (manufactured by Anton Paar Co., Ltd.), about 100 mg of the pulverized material of the matrix resin composition exuded during prepreg compression molding was sandwiched between parallel plates, and the temperature was raised at 5°C/min while the frequency was 1 Hz and the load strain was 0.2 % conditions to measure the various melt viscosities when the temperature rises from room temperature to 280°C.

In Table 1, " ρ ( _Tg+100 )" represents the melt viscosity at +100°C of the glass transition point of the resin constituting the main component of the resin composition, and " ρ ( _Tm-5 )" represents the melt viscosity at the temperature of the main component of the resin composition. The melt viscosity of the resin whose melting point is -5°C.

confirmation of reactivity

Using a rheometer (manufactured by Anton Paar Co., Ltd.), the powder matrix resin composition (MT resin) was sandwiched between parallel plates, and the temperature was raised to 280° C. at 5° C./min and then kept at 280° C. for 30 minutes. The melt viscosity of MT resin was measured under the condition of 0.2% load strain. Examples of the measurement results ( Δρ ) shown in Table 1 are as follows. In addition, the reference|standard melt viscosity is the melt viscosity at the time point which reached 280 degreeC.

⊚: Increase in melt viscosity by 5 times or more was confirmed during the holding period at 280°C.

◯: During the holding period at 280° C., an increase in the melt viscosity was confirmed to be 2 times or more.

Δ: During the holding period at 280° C., a rise in melt viscosity was not confirmed to be 2 times.

X: There was almost no rise in the melt viscosity during the holding period at 280°C.

Glass transition temperature (Tg)

The matrix resin composition was compression-molded with a mold, and cut into test pieces with a thickness of 2 mm and a diameter of 6 mm using a diamond cutter. The test piece was measured using a dynamic viscoelasticity measuring device (DMA7e manufactured by Perkin Elmer) in the range of 25 to 280°C at a temperature increase of 5°C/min, and the maximum peak of tan δ obtained was taken as the glass transition point.

Melting point (Tm)

According to the JIS K 7121:1987 method for measuring the transition temperature of plastics, it is measured using a differential scanning calorimeter (DSC).

Springback (S/B) evaluation

The springback of the molded product is determined by the amount of thickness change between the molded product after receiving a heat history at 200°C for 30 minutes and the molded product at 25°C in an atmospheric oven.

The thickness measurement uses the average value measured at three places with a micrometer, and the springback amount is calculated by the following formula.

S/B amount (%)=dimension thickness of molded body after heat history/thickness of molded body at 25°C×100.

FRP bending test

The mechanical properties (bending strength and flexural modulus) of the obtained metal-FRP composite were measured according to JIS K 7074:1988 Bending test method for fiber reinforced plastics.

FRP molding materials were laminated so that the thickness after molding became 1.0 mm, and thermocompression bonding was performed under the conditions shown in the respective examples and comparative examples. Next, a sample of the FRP composite body for a bending test was produced by adjusting the width to 15 mm and the length to 60 mm using a diamond cutter.

Also, as a pretreatment during the measurement, the sample was left to stand in an atmospheric oven set at 220° C. for 10 minutes, then taken out and left to cool to room temperature.

Determination of load deflection temperature

Refer to JIS K 7191 Plastics - Calculation method of load deflection temperature, and measure the load deflection temperature of the fiber-reinforced plastic used as the test piece.

The resin components constituting the thermoplastic resin composition are as follows.

Phenoxy resin (A)

Phenotote YP-50S (manufactured by Nippon Steel & Sumitomo Metal Chemicals, bisphenol A type, Mw=40,000, hydroxyl equivalent=284g/eq), melt viscosity at 250°C=90Pa. s.

Polyamide resin (B-1)

CM1017 (manufactured by TORAY, polyamide 6), melt viscosity at 250°C = 125Pa. s, Tm=225°C.

Polycarbonate resin (B-2)

Iupilon S3000F (manufactured by Mitsubishi Engineering Plastics Co., Ltd., Mw=36,000), melt viscosity at 280°C=1,000Pa. s, Tg=160°C, Tm=230 to 260°C.

Aromatic polyester resin (B-3)

NEH-2070 (manufactured by UNITIKA, polyethylene terephthalate), melt viscosity at 270° C. = 914 Pa. s, Tg=77°C, Tm=250°C.

Epoxy resin (C)

YSLV-80XY (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., tetramethylbisphenol F type, epoxy group equivalent=192, Tm=72°C).

Cross-linking agent (D)

BisDA (bisphenol A, diphthalic anhydride, acid anhydride equivalent: 260, melting point: 184°C, SABIC).

Production example 1

Prepare 50 parts by weight of YP-50S and 50 parts by weight of S3000F, crush and classify them respectively to form a powder with an average particle diameter D50 of 100 μm or less, and dry blend the powder with a dry powder mixer , thereby preparing the resin composition E1.

Production example 2

Prepare 77 parts by weight of YP-50S and 23 parts by weight of YSLV-80XY, which are respectively pulverized and classified to form a powder with an average particle diameter D50 of 100 μm or less. In this powder, BisDA is compared to YP -50S was blended so that the hydroxyl equivalent of 50S became 1.0 equivalent, and dry blended using a dry powder mixer to prepare resin composition E2.

Production example 3

Prepare 50 parts by weight of YP-50S and 50 parts by weight of CM1017, pulverize and classify them respectively, and form a powder with an average particle diameter D50 of 100 μm or less, and dry the powder with a dry powder mixer (Aichi Electric Co., Ltd. Resin composition E3 was prepared by dry blending with Rocking Mixer manufactured by the company.

Production example 4

Prepare 70 parts by weight of YP-50S and 30 parts by weight of NEH-2070, pulverize and classify them respectively, and form a powder whose average particle diameter D50 is below 100 μm , and use the powder in a dry powder mixer ( Aichi Electric Co., Ltd. Rocking Mixer) was dry blended to prepare resin composition E4.

Example 1

Short fibrous resin fibers (fiber diameter 29 μm , average fiber length 50 mm) and short fibrous carbon fibers (TR50S manufactured by Mitsubishi Chemical Corporation, fiber diameter 7 μm , The average fiber length is 50mm), and the mixing ratio is 50/50. These blenders are put into a pre-processing machine, and after the pre-treatment step, they are put into a carding machine to make a web in which short-fibrous resin fibers and short-fibrous carbon fibers of the resin composition E2 are uniformly mixed. The mesh was interwoven into one body by needle-punching to make a CFRP prepreg composed of a composite mat with a thickness of 7 mm.

The CFRP prepreg obtained by stacking 5 sheets was pressed in a press machine heated to 280° C. at 5 MPa for 10 minutes to produce a CFRP molded body.

Example 2

The resin composition E1 obtained in Production Example 1 was used as a reinforcing fiber base material to remove the sizing agent SA3202 (manufactured by SAKAI OVEX Co., Ltd., flat-woven defiberized carbon fiber cloth), and was charged with an electric charge in an electrostatic field. Under the conditions of load 60kV and blowing air volume 60L/min, powder coating was performed so that Vf after molding became 60%. Thereafter, heat and melt in an oven at 250°C for 3 minutes to thermally fuse the resin composition to the carbon fibers to produce a CFRP prepreg with a thickness of 0.9 mm and a resin ratio (RC) of 30%.

The obtained CFRP prepreg was pressed at 5 MPa for 10 minutes in a press machine heated to 280° C., thereby producing a CFRP molded body.

Example 3

Prepare the resin composition E2 obtained in Production Example 2 of resin for matrix, and short fibrous carbon fibers produced by needle-punching using recycled carbon fibers (manufactured by Ai-Carbon Co., Ltd., average fiber length: 50 mm) as reinforcing fibers The base material (weight per unit area: 400g/m ² ) was powder-coated using a powder coating device so that the Vf after molding would be 60% under the conditions of a charge of 60kV and a blowing air volume of 60L/min. Thereafter, heat and melt in an oven at 250° C. for 3 minutes to thermally fuse the resin composition to the carbon fiber, and produce a CFRP prepreg composed of a composite mat with a thickness of 7 mm.

The CFRP prepreg obtained by stacking five sheets was pressed in a press machine heated to 240° C. at 5 MPa for 10 minutes to produce a CFRP molded body.

Example 4

The resin composition E2 obtained in Production Example 2 was made of SA3202 without the sizing agent as the reinforcing fiber substrate, and the Vf after molding was 60% under the conditions of charge 60kV and blowing air volume 60L/min in the electrostatic field. method for powder coating. Thereafter, heat and melt in an oven at 250°C for 3 minutes to thermally fuse the resin composition to the carbon fibers to produce a CFRP prepreg with a thickness of 0.9 mm and a resin ratio (RC) of 30%.

The obtained CFRP prepreg was pressed at 5 MPa for 10 minutes in a press machine heated to 200° C., thereby producing a CFRP molded body.

Example 5

The resin composition E1 obtained in production example 1 uses SA3202 without sizing agent as the reinforcing fiber base material, and the Vf after molding becomes 60% under the conditions of charge 60kV and blowing air volume 60L/min in an electrostatic field Perform powder coating. Thereafter, heat and melt in an oven at 250°C for 3 minutes to thermally fuse the resin composition to the carbon fibers to produce a CFRP prepreg with a thickness of 0.9 mm and a resin ratio (RC) of 30%.

The obtained CFRP prepreg was pressed at 5 MPa for 10 minutes in a press machine heated to 280° C., thereby producing a CFRP molded body. After cooling the obtained CFRP molded body X1, the mechanical strength (stress at rupture point and modulus of elasticity) was measured. The results are shown in Table 1.

Example 6

The resin composition E4 obtained in production example 4 uses SA3202 without sizing agent as the reinforcing fiber base material, and the Vf after molding becomes 60% under the conditions of charge 60kV and blowing air volume 60L/min in an electrostatic field Perform powder coating. Thereafter, heat and melt the resin composition at 270°C for 3 minutes in an oven to thermally fuse the resin composition to the carbon fibers to produce a CFRP prepreg with a thickness of 0.9 mm and a resin ratio (RC) of 30%.

The obtained CFRP prepreg was pressed in a press machine heated to 270° C. at 2 MPa for 15 minutes to produce a CFRP molded body. After cooling the obtained CFRP molded body X1, the mechanical strength (stress at rupture point and modulus of elasticity) was measured. The results are shown in Table 1.

Comparative example 1

A CFRP prepreg having a thickness of 0.9 mm and a resin ratio (RC) of 30% was produced in the same manner as in Example 1 except that YP-50S crushed and classified so that D50 became 100 μm or less was used alone.

The obtained CFRP prepreg was pressed at 5 MPa for 10 minutes in a press machine heated to 280° C., thereby producing a CFRP molded body. After cooling the obtained CFRP molded body X1, the mechanical strength (stress at rupture point and modulus of elasticity) was measured. The results are shown in Table 1.

Comparative example 2

YP-50S crushed and classified so that D50 becomes less than 100 μm and SA3202 with sizing agent removed are used as reinforcing fiber base material, and the Vf after molding is determined under the conditions of charge 60kV and blowing air volume 60L/min in an electrostatic field 60% of the way to powder coating. Thereafter, heat and melt in an oven at 250°C for 3 minutes to thermally fuse the resin composition to the carbon fibers to produce a CFRP prepreg with a thickness of 0.9 mm and a resin ratio (RC) of 30%.

The obtained CFRP prepreg was pressed at 5 MPa for 10 minutes in a press machine heated to 280° C., thereby producing a CFRP molded body. After cooling the obtained CFRP molded body X1, the mechanical strength (stress at rupture point and modulus of elasticity) was measured. The results are shown in Table 1.

Comparative example 3

In place of resin composition E2, except that CM1017 pulverized and classified so that D50 becomes 100 μm or less was used alone, a CFRTP prepreg with a resin ratio (RC) of 30% was produced in the same manner as in Example 2 and For the CFRTP molded body, the mechanical strength (stress at rupture point and modulus of elasticity) was measured.

[Table 1]

As can be seen from the results shown in Table 1, compared with the case where the constituent materials are used alone, the CFRP made of the resin composition of the present invention as the matrix resin has a smaller springback value and a lower load deflection temperature even when placed in a high temperature environment. improve.

As mentioned above, the melt viscosity parameter of the resin composition that becomes the matrix resin of CFRP is within the scope of the patent application, so that it can exhibit high heat resistance above the processing temperature while using thermoplastic resin as the main component, although it is not required by super engineering plastics. High heat-resistant resins processed at high temperatures can also exhibit equivalent performance, and are useful materials in terms of processing and cost in automotive materials and aerospace fields that require heat resistance or mechanical strength in a hot environment.

(industrial availability)

The resin composition of the present invention can be used in FRTP materials, especially CFRTP materials, for structural members used in severe environments such as automobiles and aerospace.

Claims (7)

A thermoplastic resin composition, which contains a thermoplastic resin, and the thermoplastic resin composition will become a matrix resin of fiber reinforced plastic after being impregnated in a reinforced fiber base material, More than 50 wt% of the entire resin composition is a thermoplastic resin containing phenoxy resin as an essential component, When using a rheometer to heat up from room temperature to 280°C and then cool down to room temperature, the melt viscosity exceeds 10000Pa in the temperature range below 220°C. s. The thermoplastic resin composition as described in Claim 1, wherein the matrix resin is a mixture of phenoxy resin (A) and the second thermoplastic resin (B-1 to 3), and the aforementioned matrix resin contains phenoxy resin (A) 30wt % above 70wt%, the rest is the second thermoplastic resin (B-1 to 3), and the second thermoplastic resin (B-1 to 3) is selected from polyamide resin (B-1), polycarbonate resin ( One or more of the group consisting of B-2) and polyester resin (B-3). The thermoplastic resin composition according to claim 1, wherein the matrix resin contains a thermoplastic resin and an epoxy resin (C). The thermoplastic resin composition according to claim 1, wherein the resin composition to be the matrix resin exhibits mutual reactivity or crosslinkability. A fiber-reinforced plastic molding material, which is obtained by impregnating the thermoplastic resin composition as described in any one of Claims 1 to 4 in a reinforced fiber base material. A molded body formed by molding the fiber-reinforced plastic molding material as described in Claim 5. The molded article according to Claim 6, wherein the thickness change rate of the fiber-reinforced plastic after being left to cool to normal temperature after being left in a hot environment at the same temperature as the molding process for 10 minutes is more than 0% and less than 10%.