JPH08302206A - Resin composition for producing composite molded product and molding material consisting mainly of the same - Google Patents

Abstract

PURPOSE: To obtain a new resin composition for producing a sandwich composite molded product having a syntactic foam core. CONSTITUTION: A resin composition is used for producing composite molded products each having a wholly integrated sandwich structure wherein a porous core layer is existent between skin layers comprising a fiber-reinforced resin. The resin composition substantially comprises 10-65vol.% of a thermosetting matrix resin and 90-35vol.% of lightweight particles. The lightweight particles comprise (a) compressible lightweight particles such as thermally expanded hollow resin particles and (b) rigid lightweight particles such as glass balloons in a (a)/(b) volume ratio of 100/0 to 20/80, preferably 90/10 to 30/70. The composition is preferably shaped into a layer-like shape, and subsequently nipped with reinforcing fibrous sheets, separating membranes, etc. The laminated molding material is convenient for molding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition used for producing a composite molded article having a porous core or a molding material mainly containing the resin composition. More specifically, it is used when producing a composite molded article having a sandwich structure consisting of a skin layer made of fiber reinforced resin and a porous core layer,
The present invention relates to a resin composition composed of a thermosetting matrix resin and lightweight particles, and a molding material using the resin composition.

[0002]

2. Description of the Related Art As a lightweight composite molded article having a panel structure having a sandwich structure composed of a skin layer made of fiber reinforced resin (FRP) and a porous core layer as described above,
It is well known that a resin foam of polyurethane, polystyrene, polypropylene or the like is used as a core material and its upper and lower sides are covered with asbestos slate, a metal plate, a fiber reinforced resin plate (FRP plate) or the like. However, these materials have the drawback that the rigidity and compressive strength of the foam as the core material are insufficient, and the mechanical properties of the composite molded article are not sufficient.

In order to compensate for this drawback, a method is known in which a syntactic foam made by adding a large amount of glass hollow particles or the like to a resin as a core material is laminated and adhered to a surface coating material such as an FRP plate. However, all of the known methods using a preliminarily prepared core material (syntactic foam) have a drawback that adhesion between the core material and the surface coating material is difficult and peeling easily occurs.

As a means for solving this drawback, a resin mixture prepared by mixing a liquid molding resin with a fine hollow sphere filler such as glass hollow particles is applied to a fiber reinforcing material, and the resin component is permeated into the fiber reinforcing material, After the fiber reinforcement is placed on top of it, the resin mixture is pressure-cured while remaining on the surface of the fiber reinforcement to produce a sandwich molded composite molded article with a syntactic foam layer sandwiched between FRP layers. A method of doing so has been proposed (for example, Japanese Patent Publication No. 58-21579). However, this method not only requires molding with a considerably high pressure in the mold, but also because it is unavoidable that the hollow microspheres dig into the surface FRP layer, it is possible to obtain a composite molded article with good surface properties. I can't get it.

As a means for solving the above problems of the conventional method, a resin mixture prepared by mixing expandable resin particles with a liquid molding resin is housed in a molding mold so as to be sandwiched between a fiber reinforcing material and a separation membrane, A method is proposed in which the particles are heated to expand the particles, and the expansion pressure causes the resin to permeate through the separation membrane into the fiber reinforcing material on the surface and cure in that state to simultaneously form the syntactic foam layer and the skin layer. (For example, see European Patent No. 407996, Japanese Patent Publication No. 7-12613). In this method, a lightweight and tough sandwich type composite molded article can be produced in one step, but since the above particles are heated and foamed in the resin mixture at the time of molding, the expansion timing of the expandable resin particles and the curing timing of the liquid molding resin are controlled. It was necessary to match well. Also,
According to this method, since the expandable resin particles are expanded and the resin is molded in the mold, it is difficult to make the molding process continuous.

As a means for solving the above-mentioned problems, the present inventors first (1) pass the liquid molding resin on the opposite surface sides of the upper and lower reinforcing fibrous sheets, but use glass beads or the like. Place a separation membrane that does not let through lightweight filling particles,
Forming a laminate in which a resin mixture layer containing the light weight filling particles and a liquid molding resin is present between the separation membranes,
(2) Subsequently, by applying a surface pressure from the vertical direction of the laminate, at least a part of the liquid molding resin in the resin mixture is permeated into the upper and lower reinforcing fibrous sheet layers through the separation membrane, and the whole is resin. By fully wetting and discharging the air bubbles contained in the laminate to the outside, (3) and heating in that state to cure the liquid molding resin and molding it, so that the syntactic structure is achieved without foaming during molding. Method for producing composite molded article having sandwich structure having tic foam core (Japanese Patent Application No. 6-183355 and Japanese Patent Application No. 6-183355)
No. 218736) was proposed.

According to this molding method, a composite molded article having a syntactic foam core can be continuously manufactured at low cost without using expandable resin particles. As a result of further studies, the resulting composite molded article is not sufficiently lightweight, and the shrinkage of the resin during molding causes voids and swelling in the molded article, resulting in a decrease in surface properties and toughness. Turned out to be.

[0008]

SUMMARY OF THE INVENTION The present invention is intended to solve the problems of the above-mentioned method, and the first object thereof is to provide non-heat-expandable lightweight particles containing compressible particles as such lightweight particles. The present invention is to provide a novel resin composition containing compressible particles, which is preferably used in a novel molding method using a resin, and a second object thereof is to provide a molding material in which the resin composition is effectively used. Especially.

[0009]

Means for Solving the Problems As a result of intensive studies to achieve the above-mentioned objects, the present inventors have found that there is no void or swelling, and the syntax is very good in terms of lightness, surface property and toughness. In order to form a tic foam core composite molded article, the composition of the resin composition used for molding is important, and it was found that it is effective to use a resin composition containing compressible particles as lightweight particles, The invention was completed.

That is, the resin composition of the present invention is a resin used for producing a composite molded article having a sandwich structure in which a porous core layer is present between skin layers made of a fiber-reinforced resin and the whole is integrated. A composition, wherein the resin composition comprises 10 to 65% by volume of a thermosetting matrix resin (A) and 90 to 35% by volume of lightweight particles (B), and the lightweight particles (B) are compressible. It is characterized in that it contains the lightweight particles (a) and the rigid lightweight particles (b), and that the volume ratio of (a) / (b) is 100/0 to 20/80.
A resin composition for producing a composite molding having a porous core.

The thermosetting matrix resin that constitutes the resin composition of the present invention is a thermosetting resin system used for the production of ordinary composite moldings and resin moldings. What shows fluidity under the heating conditions at that time is desirable. Specific examples of the thermosetting matrix resin include epoxy resin, polyurethane resin, unsaturated polyester resin, vinyl ester resin, phenol resin, polyimide resin, acrylic urethane resin, polydicyclopentadiene resin, petroleum resin and the like. . Of these, epoxy resin, unsaturated polyester resin, phenol resin, vinyl ester resin and the like are preferable examples. These are usually used together with necessary curing agents, curing accelerators, diluents and the like.

Incidentally, the curing agent, curing accelerator, etc. are usually used by directly mixing with the above resin, but they are added and mixed in the state of being microencapsulated with a solid resin which melts or dissolves at the molding temperature. You may.

In the resin composition of the present invention, the "light weight particles" incorporated into the thermosetting matrix resin are light weight particles having organic or inorganic fine monocell and / or multicell fine hollow structures. , And the lightweight lightweight particles (a) that are already expanded but are compressed by pressurization and the rigid lightweight particles (b) that do not cause a substantial volume change by heating and pressing.

The above-mentioned compressible lightweight particles (a) are compressed and deformed (elastically or plastically) by the pressure applied during molding to reduce the volume by about 1 to 70% (preferably 5 to 50%). It is a hollow particle with a small specific gravity. Such compressible lightweight particles are hollow lightweight resin particles or porous particles obtained by pre-expanding heat-expandable fine resin particles (for example, "Matsumoto Microspheres" manufactured by Matsumoto Yushi-Seiyaku Co., Ltd.). Examples thereof include polypropylene particles. These compressible lightweight particles are one kind of non-expandable particles that do not substantially expand in volume even when reheated. However, they are compressed and deformed by pressure during molding, which is a conventional syntactic foam formation. It is different from inorganic hollow particles such as glass beads used for.

The specific gravity (expressed as true specific gravity) of these compressible lightweight particles is preferably 0.3 or less, but the specific gravity is 0.
It is more preferable that the weight is 2 or less. The size of the compressible lightweight particles is usually 0.0
Those having a range of 1 to 5 mm, preferably 0.05 to 2 mm are suitable.

Specific examples of such compressible lightweight particles include:
For example, heat-expandable resin particles such as "Matsumoto Microspheres" manufactured by Matsumoto Yushi-Seiyaku Co., Ltd., "Expansel" manufactured by Nobel Co., Ltd., "Eslen beads" manufactured by Sekisui Chemical Co., Ltd. Alternatively, it may be expanded by heating in an inert gas atmosphere.

In the resin composition of the present invention, the rigid lightweight particles (b), which are lightweight particles that can be used in combination with the above-described compressible lightweight particles (a), are minute particles having rigidity that are difficult to deform even under pressure. Yes, for example, generally "glass balloons",
It is an inorganic hollow particle called “shirasu balloon”, “silica balloon” or the like. In order to reduce the weight of the desired composite molded article, when rigid lightweight particles are used, it is preferable to use rigid lightweight particles having a specific gravity (expressed as true specific gravity) of 0.8 or less, particularly 0.6 or less. Glass hollow particles can be mentioned as a typical rigid lightweight particle. The size of the rigid lightweight particles is preferably 0.01 to 5 mm, particularly 0.1 to 2 mm in terms of average particle size.

Specific examples of such rigid lightweight particles include glass balloons such as "Glass Bubbles" manufactured by Sumitomo 3M Ltd., "CELLSTAR" manufactured by Asahi Glass Co., Ltd., "Fillite" manufactured by Nippon Philite Co., Ltd., and the like. Inorganic hollow particles can be mentioned.

The resin composition for molding a composite molded article having a porous core according to the present invention is substantially the same as the thermosetting matrix resin (A) described above and the compressible lightweight particles (a) or the compressible lightweight particles. (A) and rigid lightweight particles (b) are used as the lightweight particles (B).

The thermosetting matrix resin (A) and the lightweight particles (b) are mixed in a volume ratio of 10 to 65% by weight of the thermosetting matrix resin and 90 to 35% by weight of the lightweight particles.
The thermosetting matrix resin is preferably 15 to 60% and the lightweight particles are 85 to 40%.

The term "volume of the thermosetting matrix resin" as used herein refers to the matrix resin itself (resin component in a narrow sense), as well as a broad range of thermosetting properties including a curing agent, a curing accelerator and a diluent used for molding. It refers to the total volume of the entire resin system (curing system). The volume of the lightweight particles is the volume in a steady state before being pressed during molding.

When the volume ratio of the light-weight particles in the resin composition is more than the above range, it is advantageous for weight reduction, but not only the fluidity of the resin composition at the time of molding is lowered, but also the resin in the composite molded article is deteriorated. Is insufficient, which leads to deterioration of the properties of the composite molded article, which is not preferable. On the other hand, if the volume ratio of the lightweight particles is less than the above range, the effect of reducing the weight of the molded article cannot be expected, which is not preferable.

Further, in the resin composition of the present invention, the ratio of the compressible lightweight particles and the rigid lightweight particles constituting the lightweight particles is such that compressive lightweight particles / rigid lightweight particles (volume ratio) = 10.
It should be in the range of 0/0 to 20/80. If the ratio of the compressible lightweight particles to all the lightweight particles is lower than 20% by volume, the repulsive (compressing pressure) force of the compressed particles at the time of molding tends to be small, and the resulting composite molded article tends to have a poor surface condition. , A good composite molded article cannot be obtained. The preferred mixing ratio (volume ratio) of the compressible lightweight particles and the rigid lightweight particles in the present invention is in the range of 90/10 to 30/70, and within this range, a composite molded article having particularly good surface properties is provided. To be done.

As described above, the resin composition of the present invention is characterized by mixing fine lightweight particles containing compressible lightweight particles and a thermosetting matrix resin in a predetermined ratio. For the purpose of further improving moldability or the purpose of improving the mechanical properties of the molded product, if necessary,
It is also possible to replace some of the lightweight particles, specifically some of the rigid lightweight particles, with other components. Examples of such other components include milled glass, silica, mica, calcium carbonate, silica sand, fillers such as kaolin, and heat-expandable lightweight particles. Furthermore, it is also possible to add a crushed product of a recovered product (used product, defective product, process waste, etc.) of the used foam core FRP composite molded product. The proportion of such other components should be appropriately selected within a range that does not impair the characteristics of the resin / fat composition of the present invention, but is 40% by volume or less, particularly 30% by volume or less of the lightweight particles. Is preferred.

As described above, the resin composition according to the present invention is a mixture mainly composed of matrix resin and lightweight particles, and is usually deformable or amorphous having fluidity or adhesiveness to each other. Although it is in a state, it is possible to control the fluidity at room temperature by adjusting the mixing ratio. As a result, the resin composition can be formed into a lump, a grain, or a sheet. The lump-shaped or granular resin composition can be handled by weight measurement and the like, and the sheet-shaped resin composition can also measure the area as a long product by controlling the thickness thereof.

The above sheet-shaped resin composition can be used as a molding material in which the upper and lower surfaces thereof are sandwiched by another thin material. Such a thin material is extremely effective for maintaining the shape of the sheet-shaped resin composition, and can be used for molding a composite molded product while the surface of the resin composition is covered, so that a very useful molding material can be provided.

For example, by using a flexible film that can be peeled off during molding as the thin leaf material, the handleability of the sheet-shaped resin composition is significantly improved. In addition, on both the upper and lower sides of the sheet-shaped resin composition, a separation membrane that allows the matrix resin to pass but does not pass the lightweight particles is laminated, and if necessary, the upper and lower sides thereof may be covered with a reinforcing fibrous sheet for strengthening. When a molding material having a laminated structure composed of fibrous sheet / separation membrane / resin composition of the present invention / separation membrane / reinforcing fibrous sheet is used, it may be placed in a molding die as it is or after being cut to a predetermined size Since it can be used for molding, the molding operation can be easily performed.

When the separation membranes are laminated so as to sandwich the resin composition, both sides (ends) of the upper and lower separation membranes after lamination.
Alternatively, the resin mixture may be sealed by joining them together by means such as suturing, adhering, and fusing. Further, a product obtained by directly sandwiching the above resin composition between reinforcing fibrous sheets is also a useful molding material in the production of a composite molded product.

The above-mentioned lump, granular or sheet-shaped resin composition is usually a mixture of uncured matrix resin and lightweight particles, but for controlling the fluidity of the resin composition or improving molding conditions. Therefore, the thermosetting matrix resin can be formed into a partially polymerized prepreg.

The resin composition of the present invention is coated with a flexible film which can be peeled off at the time of molding in order to improve the shape retention and handleability of the resin composition in sheet form. A resin composition is sandwiched between two films, or a separation membrane through which matrix resin passes but lightweight particles does not pass is laminated on the upper and lower surfaces of a sheet-shaped resin composition. The outermost layer of the reinforcing fibrous sheets laminated on both upper and lower sides thereof may be covered with a peelable flexible film to form a sheet-shaped molding material having a multilayer sandwich structure, and in many cases, it is configured as such. Is preferred.

Examples of the flexible film include polyesters such as polyethylene terephthalate, polyethylene,
A film such as polyolefin such as polypropylene, nylon, polyvinyl chloride, polyvinylidene chloride, cellophane, etc., metal foil, or a thin non-woven fabric or paper impregnated with resin to make it liquid impermeable can be selected as appropriate. used.

On the other hand, as the separation membrane, one having a function of separating the matrix resin and the lightweight particles is used, and for example, a thin fiber sheet and / or a porous sheet having a small opening is used. Specific examples of the fibrous sheet include various natural fibers, synthetic fibers, woven fabrics such as inorganic fibers, knits, non-woven fabrics, braids, papers, and the like, and specific examples of the porous sheet include a sheet having continuous ventilation holes or As the film, a foamed sheet of polyurethane, polystyrene, polypropylene or the like, or a porous membrane obtained by stretching and extracting a sheet of polyethylene, polypropylene, polysulfone or the like is used. As a typical separation membrane, "Unicell"
Polyester non-woven fabric known under the trade name of

In the present invention, a molding material in which a reinforcing fibrous sheet is laminated above or below the above resin composition, directly or via a separation membrane, may be used in some cases. The reinforcing fibrous sheet is usually used as a sheet, although it depends on the shape of the target molded product. Examples of the form of these fibers include woven fabric, knitted fabric, non-woven fabric, mat, paper, and unidirectionally aligned roving. The type of reinforcing fiber used in the present invention is not particularly limited, but it is an organic or inorganic fiber usually used as a reinforcing material for a composite molded article, for example, glass fiber, carbon fiber, silicon nitride fiber, metal. Fibers, aramid fibers, polyarylate fibers, high-strength polyethylene fibers, etc. can be used. In addition to these fibers, polyester fiber,
Polyamide fiber, polyvinyl alcohol fiber, rayon fiber, natural fiber and the like can also be used. Above all, it is preferable to use high-strength, high-modulus fibers such as glass fibers, carbon fibers and para-aramid fibers.

In this molding material as well, in order to improve shape retention and handleability, the upper and lower surfaces or one surface of the reinforcing fibrous sheet may be covered with a flexible film. In this case,
The flexible film may be used for molding without being peeled off during molding.

Hereinafter, in order to more specifically explain the features and advantages of the resin composition according to the present invention, the production of a composite molded article having a porous core using the resin composition according to the present invention will be described.

That is, the above-mentioned resin composition of the present invention is in the form of a paste, or is formed in the form of granules, lumps or sheets in advance, and the reinforcing fibrous sheet is provided directly above or below the resin composition layer or through a separation membrane. To form a laminate covered with, by pressing the laminate from above and below, to squeeze out the matrix resin in the resin composition to partially penetrate the resin into the upper and lower reinforcing fibrous sheet layers,
By heating in that state to cure the resin, a composite molded product having a sandwich structure having a porous core and being lightweight, tough, and having good surface properties can be obtained.

Further, a molding material in which both upper and lower surfaces of the sheet-shaped resin composition are covered with flexible films, or separation films are arranged above and below the resin composition and the upper and lower surfaces thereof are covered with flexible films. In the case of using a molding material, it is natural that the film is used for molding after peeling off the film.

Since the resin composition of the present invention contains at least 20% or more of compressible lightweight particles as lightweight particles, the penetration of the matrix resin by the pressurization at the time of molding is good, and the shrinkage due to the curing of the matrix resin is suppressed. As a result, the volume of the compressible lightweight particles is recovered, and a molded product having good surface properties without sink marks is obtained.

When a resin composition containing both compressible lightweight particles and rigid lightweight particles is used, the strength of the core portion is improved and a better composite molded article can be obtained.

At this time, in molding the above-mentioned composite molded article, a separation membrane which allows uncured matrix resin to pass but lightweight particles to pass is disposed between the resin composition and the reinforcing fibrous sheet layer. Molding is preferred. That is, due to the arrangement of the separation membrane, the lightweight particles that move along with the matrix resin during the molding process by pressurization and heating,
It has an excellent effect of impregnating the space of the reinforcing fibrous sheet into the space, and further suppressing the deterioration of the surface property by appearing on the surface of the molded product. As such a separation membrane, one kind or two or more kinds of thin fiber sheets and / or porous sheets having a small opening as described above are used. Thus, when molding a composite molded article using the resin composition of the present invention, between the reinforcing fibrous sheet for forming the surface layer portion and the resin composition, by disposing a separation membrane, molding, It is extremely effective in obtaining a molded product having a good surface property.

Due to the presence of such a separation membrane, the reinforcing fibrous sheet is effectively compressed and densified by pressurization at the time of molding, and a matrix is formed from the resin composition sandwiched (enclosed) by the separation membrane. The resin component is squeezed out and selectively penetrated into the reinforcing fibrous sheet in the surface layer. At the same time, since lightweight particles are prevented from entering the reinforcing fiber component, a dense and compact fiber-reinforced resin layer is formed on the surface layer portion, and a lightweight syntactic foam layer is formed on the core portion. And is extremely effective in producing a composite molded product having a porous core sandwich structure.

Further, since the resin composition and the molding material have substantially no thermal expansion property, it is not always necessary to use a closed molding die in order to produce a composite molding. It is industrially extremely advantageous because continuous molding can be performed by using a continuous molding device capable of transporting and heating while controlling the upper and lower surfaces of the laminate.

FIG. 1 shows an example of continuously producing a sheet-shaped molding material using a paste-like resin composition of the present invention, and an example of continuously producing a molded product using the resin composition. , Show at the same time.

The apparatus shown in FIG. 1 can be applied to both a case where a molding material is continuously manufactured using a paste resin composition and a case where a paste resin composition is continuously molded. Is.

First, the case of producing a molding material with the apparatus shown in FIG. 1 will be described. Resin mixer (14) in the apparatus of FIG.
A thermosetting matrix resin according to the present invention, a compressible lightweight particle, and a fluid resin composition comprising a rigid lightweight particle to be added as necessary are supplied to the flexible film (1
1, 17), the reinforcing fibrous sheets (12, 16), and the separation membranes (13, 15) are pulled out by respective take-out rollers (1, 2, 3, 4, 5, 6) to form a flexible film. (11), the reinforcing fibrous sheet (12) and the separation membrane (13) are superposed in this order, and the resin composition from the resin mixer (14) is applied in layers on the laminate, Further thereon, a separation membrane (15), a reinforcing fibrous sheet (16) and a flexible film (17) are laminated in this order, and a reinforcing fibrous sheet / separating membrane / resin composition / separating membrane / reinforcing A laminated sheet material in which the upper and lower sides of a laminated body made of a fibrous sheet are covered with a polyester film is continuously formed.

Then, the laminated sheet-like material is a drum (1
8 and 18 ') is pressed by a series of roller groups (19) to adjust the thickness, and is taken as a sheet-shaped molding material (22) to be a target molding material. At this stage, the heating box (21) of FIG. 1 is not used and the resin is not cured.

The continuous-length sheet-shaped molding material (22) thus obtained is cut into an appropriate size and used for molding. This molding material is a composite molded article having a porous core, which is obtained by peeling off the upper and lower films before molding and putting it in a mold or the like.

Next, the case where the paste-like resin composition is continuously molded using the apparatus shown in FIG. 1 will be described.

In this continuous molding method, the laminated body composed of the reinforcing fibrous sheet / separating film / resin composition / separating film / reinforcing fibrous sheet formed in the same manner as described above is covered with polyester films. The laminated sheet-like material was pressed by the drums (18, 18 ′) and the roller group (19) to squeeze the resin into the surface layer, and the laminated body was continuously heated in the same manner as in Example 4 described later. Introduced in (21), the resin is cured by heating it above the curing temperature of the matrix resin to cure the resin, whereby the desired sandwich-type composite molded article having a syntactic foam core is obtained.

[0050]

The resin composition for producing a composite molded article having a porous core of the present invention is a resin composition comprising a thermosetting matrix resin and specific lightweight particles containing compressible lightweight particles. , And is preferably characterized in that the compressible lightweight particles and the rigid lightweight particles are used in combination at a specific ratio, so that the compressive lightweight particles are compressed when pressure is applied during molding, so that the repulsive pressure in the mold is reduced. Can hold
As a result, not only volume contraction in the curing process of the matrix resin is compensated, but also unnecessary bubbles are discharged out of the mold. Further, the molding material can be molded in a state of being pressed against the inner wall surface of the molding die, so that a molded product having more excellent surface properties can be obtained.

Further, since the resin composition of the present invention has substantially no thermal expansion property, a composite molding can be produced not only by a batch-type molding method using a mold for molding but also by a conveyor. Molding can also be carried out by a continuous method in which a molding material is sandwiched and conveyed by a heat-molding method or the like, which is extremely advantageous industrially.

Thus, since the composite molded article having a porous core obtained by using the resin composition of the present invention is lightweight and tough and has excellent surface properties, it can be used as, for example, a building floor board material or a vertical partition panel. Widely used for various purposes such as construction materials such as heat insulating wall materials and bench materials, materials for transportation equipment such as ships, aircraft, railway vehicles, automobiles, materials for land or sea containers, materials for electric / communication equipment and housings. be able to.

[0053]

EXAMPLES Examples and comparative examples of the present invention will be shown below. However, these examples are for explaining the present invention in more detail, and the present invention is not limited thereto.

In the following examples, "parts" means parts by weight unless otherwise specified.

[Example 1] Unsaturated polyester resin at room temperature ("Polylite FG104" manufactured by Dainippon Ink and Chemicals, Inc.)
N ") to 100 parts by weight of benzoyl peroxide (BPO) and cumene hydroperoxide (C) as a curing agent.
HP) total amount 1.4 parts and dimethylaniline (DMA) 6.0 parts as a curing accelerator were added and mixed well, and then compressible lightweight particles ("Matsumoto Micros" manufactured by Matsumoto Yushi-Seiyaku Co., Ltd.). "Fair LF-100CA": Specific gravity 0.1
7.8 parts and rigid lightweight particles ("Glass Bubbles K-1 manufactured by Sumitomo 3M Ltd .: specific gravity of 0.
No. 13, particle size 0.1 to 1 mm) 10.6 parts were added and mixed to prepare a resin composition.

The volume ratio of the thermosetting matrix resin to the lightweight particles in this resin composition was 39/61, and the volume ratio of the compressible lightweight particles to the rigid lightweight particles was 41 /.
It was 59.

The resin composition having a compressibility of the compressible lightweight particles (volume change rate of the compressible lightweight particles before and after molding) of 44% by volume was separated from the mold by a separation membrane (Unicell Co., Ltd.).
Polyester non-woven fabric "UNICEL BT0908W":
Unit weight 40 g / m ² ) / Reinforcing fibrous sheet (glass fiber chopped strand mat “Glaslon CM305” manufactured by Asahi Fiber Glass Co., Ltd .: unit weight 300 g / m ² ) Layered with a substantially uniform thickness on a laminate It is supplied, and the separation membrane and the reinforcing fibrous sheet are laminated thereon in this order to form a laminate composed of the reinforcing fibrous sheet / separating membrane / resin composition / separating membrane / reinforcing fiber sheet. Formed.

Next, the laminate is uniformly pressed in the vertical direction to allow the matrix resin to sufficiently permeate into the upper and lower reinforcing fibrous sheet layers, and then the mold (8
30 mm × 553 mm × 7.5 mmt: cavity volume 3442 cm ³ ) was set in the lower mold, the upper mold was closed, and after holding for 6 minutes, the mold was opened and the molded product was taken out.

The thus obtained sandwich type composite molded article having a syntactic foam core exhibited excellent surface properties free from voids and swelling. It was also confirmed that the weight of the molded product was 1.86 Kg and the specific gravity of the molded product was 0.54, which was also excellent in lightness.

[Comparative Example 1] A resin in which light weight particles are not added by using the unsaturated polyester resin, the curing agent / curing accelerator and the reinforcing fibrous sheet (glass fiber chopped strand mat) used in Example 1 A composition was prepared and a composite molded article was molded using the resin composition in the same mold as in Example 1. The specific gravity of the obtained molded product is 1.59.
It was confirmed that it was heavy and inferior in lightness.

Comparative Example 2 A resin was prepared in the same manner as in Example 1 except that 18.1 parts of the rigid lightweight particles were used alone instead of using the compressible lightweight particles and the rigid lightweight particles together. A composition was prepared, and using this resin composition,
An attempt was made to mold with a mold under the same conditions as in Example 1. The specific gravity of the obtained syntactic core type composite molded article was relatively light at 0.61. However, the surface of the molded article had sink marks and swelling due to curing shrinkage, and many voids were observed on the surface. It was

That is, the volume ratio of the matrix resin and the lightweight particles of the resin composition of this comparative example is 39/61, and the volume ratio of the compressible lightweight particles and the rigid lightweight particles is 0/100. It was not possible to obtain a composite molded article having a good surface property.

[Example 2] 100 parts of a phenol resin ("Dai Slick 106" manufactured by Dainippon Ink Co., Ltd.) and 1 part of a curing agent ("Dai Slick 102C" manufactured by Dainippon Ink Co., Ltd.)
After thoroughly mixing 0 parts, the compressive lightweight particles (“Matsumoto Microspheres TEM-8” manufactured by Matsumoto Yushi-Seiyaku Co., Ltd.) were heated in an oven and expanded about 20 times to obtain a particle size of 0. A resin composition was prepared by mixing 6.0 parts of 02 to 0.05 mm, hollow particles having a specific gravity of 0.05) with 8.5 parts of rigid lightweight particles (the same as the rigid lightweight particles of Example 1). did.
The volume ratio between the matrix resin and the lightweight particles in this example was 33/67, and the volume ratio between the compressible lightweight particles and the rigid lightweight particles was 64/36.

The compressibility of the compressible lightweight particles is 40% by volume.
The above resin composition and the reinforcing fibrous sheet
Fiberglass Chopped Strand made by Fiber Glass Co., Ltd.
Domat "Glaslon CM455": Metsuke 450g / m
²) And the same separation membrane as in Example 1,
Similarly, reinforcing fibrous sheet / separation membrane / resin composition / min
Form a laminate consisting of the membrane / strengthening fibrous sheet,
Mold (300mm × 210m)
m × 10 mmt: cavity volume 630 cm ³Inside)
Set and close the mold. Hold in this state for 10 minutes
Sufficiently impregnated the top and bottom reinforcing fibrous sheets with Trix resin
After curing, the mold was opened and the molded product was taken out.

The sandwich type composite molded article having the syntactic foam core thus obtained showed good surface properties without voids or swelling. The weight of the molded product is 357.
It was confirmed that the g and the specific gravity were as light as 0.57.

[Example 3] Unsaturated polyester resin ("Polylite FG801" manufactured by Dainippon Ink and Chemicals, Inc.) 100
Parts and curing agent (“Kayaester O-5” manufactured by Nippon Kayaku Co., Ltd.)
0 ") and 0.3 parts were mixed well, and then 8.5 parts of compressive lightweight particles (polypropylene foam particles" 15P "manufactured by JSP Corp .: average particle size of about 2 mm, specific gravity of 0.08) and Example 1" were used.
And 11.1 parts of the same rigid lightweight particles were added and mixed to prepare a resin composition. In this example, the volume ratio of the matrix resin to the lightweight particles was 31/69, and the volume ratio of the compressible lightweight particles to the rigid lightweight particles was 54/46.

Using the same resin composition as described above and the same reinforcing fibrous sheet and separation membrane as in Example 1 such that the compressibility of the compressible lightweight particles was 53% by volume, the reinforcing fiber was prepared in the same manner as in Example 1. A laminated body composed of quality sheet / separation membrane / resin composition / separation membrane / reinforcing fibrous sheet was formed and set in the same mold as in Example 2 preheated to 130 ° C., and the mold was closed. After holding in this state for 7 minutes, the mold was opened and the molded product was taken out.

The obtained sandwich type composite molded article having a syntactic foam core is excellent in surface properties without voids and swells, and has a light weight of 331 g and a specific gravity (apparent specific gravity) of 0.53. Was confirmed.

Example 4 Using the resin composition of the present invention, a composite molded product having a sandwich structure having a syntactic foam core layer was continuously manufactured by the apparatus shown in FIG.

That is, the unsaturated polyester resin prepared in Example 1, a resin composition comprising compressible lightweight particles and rigid lightweight particles, the same reinforcing fibrous sheet and separation membrane as in Example 1 were used, and the resin of FIG. The resin composition prepared in Example 1 was supplied to the mixer (14) so that the compression rate was 10%,
Of the polyester film (11, 17), the reinforcing fibrous sheet (12, 16) and the separation membrane (13, 15) are set and pulled out from the roll by respective take-out rollers, and the polyester film (11 ), The reinforcing fibrous sheet (12) and the separation membrane (13) are superposed on each other, and the resin mixer (14) is placed thereon.
The resin composition was supplied in layers. Further, on the resin composition layer, a separation membrane (15) and a reinforcing fibrous sheet (1
6) and the polyester film (17) are superposed in this order to form a laminated body composed of a reinforcing fibrous sheet / separation membrane / resin composition / separating membrane / reinforcing fibrous sheet, and the polyester film is placed on the upper and lower sides It is not covered with (11, 17).
8 ') is pressed by a series of roller groups (19) and regulated to a flat surface, the matrix resin in the resin composition in the laminate is squeezed out, and the upper and lower (surface layers) are reinforced through a separation membrane. After permeating the fibrous sheet, heating box (2
By heating in 1) to cure the resin, a composite molded article having a syntactic foam core layer was continuously produced.

The obtained composite molded article had excellent surface properties without voids or swelling on the surface. Further, it was confirmed that the specific gravity of this molded product was 0.53, which was extremely light.

Example 5 After mixing 100 parts of an epoxy resin (“Epicote 828” manufactured by Yuka Shell Co., Ltd.) and 22 parts of a curing agent (“Epicure Z” manufactured by Yuka Shell Co., Ltd.) at room temperature , Compressible lightweight particles ("Matsumoto Microsphere F80ED" manufactured by Matsumoto Yushi-Seiyaku Co., Ltd.): specific gravity of 0.
No. 02, average particle size 0.02 to 0/08 mm) and 3.3 parts of the same rigid lightweight particles used in Example 1 were added and mixed to prepare a resin composition.

The volume ratio of the matrix resin (epoxy resin curing system) to the lightweight particles in this resin composition is 30 /.
The volume ratio of the compressible lightweight particles to the rigid lightweight particles was 81/19.

As in Example 1, the above resin composition was formed into a laminate comprising a reinforcing fibrous sheet / separation membrane / resin composition / separating membrane / reinforcing fibrous sheet, and used in Example 1. After setting in the mold, close the mold and
Hold for 0 minutes. After cooling the mold, the mold was opened and the molded product was taken out. It was confirmed that the obtained sandwich-type composite molded article having a syntactic foam core had good surface properties, and the specific gravity of the molded article was 0.51, which was extremely lightweight.

[Example 6] 100 parts of epoxy resin ("Epiclon 850" manufactured by Dainippon Ink and Chemicals, Inc.) and a curing agent ("Epicure 113" manufactured by Yuka Shell Co., Ltd.) 31.7
Parts and a curing accelerator (boron trifluoride / monoethanolamine) 1.0 part were mixed at room temperature, and then compressible lightweight particles (Matsumoto Yushi-Seiyaku Co., Ltd. "Matsumoto Microspheres TEM-8"): (Same as that used in Example 2)
3.4 parts and 25.2 parts of rigid lightweight particles (“Glass Bubbles K37” manufactured by Sumitomo 3M Ltd .: specific gravity 0.37) were added and mixed. The volume ratio of the matrix resin and the lightweight particles in the obtained resin composition is 47/53,
The volume ratio of the compressible lightweight particles to the rigid lightweight particles in the lightweight particles was 50/50.

This resin composition was formed into a laminate composed of a reinforcing fibrous sheet / separating membrane / resin composition / separating membrane / reinforcing fibrous sheet in the same manner as in Example 1. This product was easy to handle and could be easily molded by directly supplying it to the molding process.

In the molding step, after setting in the mold used in Example 1, the mold was closed and held at 140 ° C. for 6 minutes. The sandwich type composite molded article having a syntactic foam core which was taken out after opening the mold after cooling the mold had good surface properties, and the specific gravity of the molded product was 0.70, which was also excellent in lightness.

[Brief description of drawings]

FIG. 1 is a schematic view of a process and an apparatus for forming a resin composition of the present invention into a sheet-shaped molding material or continuously producing a composite molded article using the resin composition of the present invention.

[Explanation of symbols]

 1, 2, 3, 4, 5, 6: Take-out roller 11, 17: Polyester film 12, 16: Reinforcing fiber sheet 13, 15: Separation membrane 14: Resin mixer 18, 18 ': Drum 19: For pressing Roller group 20, 20 ': Metal endless belt 21: Heating (or cooling) box 22: Composite molded product (or sheet-shaped molding material)

Claims (10)

[Claims] 1. A resin composition used for producing a composite molded article having a sandwich structure in which a porous core layer is present between skin layers made of a fiber reinforced resin and integrated as a whole, the resin composition comprising: The composition is a thermosetting matrix resin (A) 10 to 65% by volume and lightweight particles (B) 90 to 35.
% Substantially and the light weight particles (B) include compressible light weight particles (a) and rigid light weight particles (b), and the volume ratio of (a) / (b) is 100 / 0-20 /
80 is a resin composition for producing a composite molded article. 2. The volume ratio of (a) / (b) is 90/1.
The resin composition for producing a composite molded article according to claim 1, wherein the resin composition is 0 to 30/70. 3. A molding material for producing a composite molded article, characterized in that the resin composition according to claim 1 or 2 is formed into a sheet shape, a lump shape or a granular shape. 4. A molding material for producing a composite molded article, characterized in that the resin composition according to claim 1 or 2 is formed into a sheet, and both upper and lower surfaces thereof are covered with a thin material. . 5. The molding material for producing a composite molded article according to claim 4, wherein the thin leaf material is a separation membrane that allows the thermosetting matrix resin to pass through but does not allow the lightweight particles to pass therethrough. 6. The molding material for producing a composite molded article according to claim 4, wherein the thin leaf material is a reinforcing fibrous sheet. 7. The molding material for producing a composite molded article according to claim 4, wherein the thin material is a flexible film. 8. The molding material for producing a composite molded article having a porous core according to claim 5, wherein the upper and lower surfaces of the separation membrane are covered with flexible films. 9. A separation membrane and a reinforcing fibrous sheet are arranged on both upper and lower sides of the layer of the resin composition according to claim 1 or 2, and the reinforcing fibrous sheet / separation membrane / resin composition / separation is provided. A molding material for producing a composite molded article, which is a laminate of a membrane / fiber sheet for reinforcement. 10. A separation film and a reinforcing fibrous sheet are arranged on both upper and lower surfaces of the layer of the resin composition according to claim 1 or 2, and the upper and lower surfaces thereof are covered with a flexible film,
A molding material for producing a composite molded article, which is a laminate of flexible film / fibrous sheet for reinforcement / separation membrane / resin composition / separation membrane / fibrous sheet for reinforcement / flexible film.