JP2016010953A - Resin foam for forming complex and method of producing fiber-reinforced complex - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method that makes it possible to readily produce a fiber-reinforced complex with excellent dimensional accuracy, and a resin foam for forming a complex that is useful for such a production method.SOLUTION: The present invention provides a resin foam 6 for forming a complex that comprises a foaming agent of 0.1-5.0 mass%, and has an expansion pressure of 0.1-20 mN/mmor less at a temperature where a dimensional change rate by heating becomes +20%. The present invention also provides the resin foam 6 that comprises a foaming agent and shows a specific thermal expansion property. Further, the present invention provides the resin foam 6 that comprises a plurality of thermoplastic resin foaming particles thermally fused together.

Description

  The present invention relates to a resin foam for forming a composite used for forming a fiber reinforced composite in which a fiber reinforced resin material and a resin foam are laminated and integrated, and such a resin foam for forming a composite. The present invention relates to a method for producing a fiber reinforced composite, which is used to produce a fiber reinforced composite.

  In recent years, fiber-reinforced resin materials reinforced with fibers are lightweight and have high mechanical strength. Therefore, the bodies and interior materials of moving bodies such as vehicles, ships, and aircraft, and wind turbine blades for wind power generation are used. Opportunities for use in members that require high mechanical strength and light weight, such as housings for electronic devices, are increasing.

In recent years, the fiber reinforced resin material has been required to have not only mechanical strength and light weight but also shock absorption.
Against this background, fiber reinforced composites in which a fiber reinforced resin material is laminated and integrated on the surface of a core material made of a resin foam have come to be used for such applications.
That is, since the resin foam for forming the fiber reinforced composite (resin foam for forming the composite) is lower in density and excellent in buffering properties than the fiber reinforced resin material, the member made of the fiber reinforced composite is As a whole, it is superior in light weight and shock-absorbing properties compared to those formed of a fiber reinforced resin material.

As a method for producing this type of fiber reinforced composite, for example, a method described in Patent Document 1 below is known.
That is, in the following Patent Document 1, a method for forming a composite sandwich core molding member, in which a thermoelastic rigid foam core (foamed core) is molded into a desired shape, the preformed foam core is wrapped with a woven fabric, and then a mold is formed. After placing the preformed foam core inside, inject liquid thermosetting resin to surround and wet the woven fabric wrapped around the preformed foam core, and then expand the rigid foam core A method has been proposed in which heating of the rigid foam core is terminated after the woven fabric surrounding surface of the foam core is pressed against the internal constraining surface of the mold.

  Further, in Patent Document 2 below, a step of forming a laminate of prepreg sheets by laminating a plurality of prepreg sheets configured to include reinforcing fibers on at least the uppermost part of the outer peripheral surface of the core material; There is disclosed a method for manufacturing a robot hand member that includes a heating step of heating and thermosetting the laminated member formed in the step to form an FRP member integrated with a core material.

JP-A 63-162207 JP 2002-292592 A

The fiber reinforced composite as described above has a fiber reinforced resin material made of a thermosetting resin, and utilizes the adhesiveness exhibited during the thermosetting reaction of the thermosetting resin, and the fiber reinforced resin material and the resin. It is produced by a method in which the foam is laminated and integrated.
However, in the method of manufacturing a fiber reinforced composite using a fiber reinforced resin material made of a thermosetting resin, it takes a relatively long time until the thermosetting resin is cured, and the production efficiency of the fiber reinforced composite is increased. Has a problem that it is difficult to sufficiently improve.
Although it is conceivable to use a highly reactive thermosetting resin to solve such problems, a highly reactive thermosetting resin generally exceeds a certain level from the production because the curing reaction proceeds even at room temperature. Sufficient adhesiveness may not be exhibited in a prepreg sheet or the like after a period.
In addition, in the case of impregnating a fiber material with a liquid thermosetting resin during the production of a fiber reinforced composite, a problem relating to insufficient adhesion due to the progress of the curing reaction by adopting a two-component type thermosetting resin However, a highly reactive two-component thermosetting resin generally has severe cure shrinkage, and may cause a problem that it is difficult to obtain a fiber-reinforced composite having a desired shape.

Further, in order to solve the above problems, it is conceivable to produce a fiber reinforced composite by heat-sealing a resin foam or a fiber reinforced resin material containing a thermoplastic resin by pressing them. .
That is, a pressure by a press is applied between the resin foam and the fiber reinforced resin material in a state where the thermoplastic resin contained in the resin foam or the fiber reinforced resin material is softened, and the heat fusion is performed by this pressure. By implementing, the time required for the lamination and integration of the resin foam and the fiber reinforced resin material can be shortened as compared with the case of using a thermosetting resin.

  On the other hand, if a resin foam containing a thermoplastic resin is used, the resin foam softens during heat fusion, making it difficult to generate sufficient pressure with the fiber-reinforced resin material. If the resin foam is generated, the resin foam is compressed and deformed, and it may be difficult to obtain a fiber-reinforced composite having a desired shape.

  An object of the present invention is to solve such a problem, and provides a resin foam for forming a composite suitable for easily producing a fiber-reinforced composite having excellent dimensional accuracy. It is an object of the present invention to provide a method for producing a fiber-reinforced composite capable of easily producing an excellent fiber-reinforced composite.

The present invention relating to a resin foam for forming a composite for solving the above problems is used for forming a fiber reinforced composite in which a fiber reinforced resin material and a resin foam are laminated and integrated. And the fiber reinforced resin material include a thermoplastic resin, and a resin for forming a composite used for forming a fiber reinforced composite in which the resin foam and the fiber reinforced resin material are laminated and integrated by heat fusion a foam blowing agent containing 5.0 wt% or less than 0.1 wt%, dimensional change upon heating the inflation pressure at the + 20% and becomes temperature 0.1 mN / mm ³ or more 20 mN / mm ³ The following resin foam for forming a composite is provided.

  Moreover, this invention which concerns on the manufacturing method of the fiber reinforced composite for solving the said subject provides the method of producing a fiber reinforced composite using the above resin foams for complex formation.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method which can manufacture the fiber reinforced composite_body | complex excellent in the dimensional accuracy easily can be provided.

It is the schematic cross section which showed an example of the manufacturing apparatus of resin expanded particle. It is the schematic diagram which looked at the multi-nozzle mold from the front. It is the figure which showed the orientation of the fiber which comprises the fiber reinforced resin material. It is the figure which showed the orientation of the fiber which comprises the fiber reinforced resin material. It is sectional drawing which showed the laminated body. It is the schematic cross section which showed the manufacture point of the fiber reinforced composite. It is the schematic cross section which showed the other manufacturing point of the fiber reinforced composite_body | complex.

The embodiment of the present invention will be described below by taking as an example the case where the fiber-reinforced composite to be produced is prismatic.
The fiber reinforced composite of this embodiment is composed of a prismatic core material and a sheet-shaped coating material that covers the core material.
In the fiber reinforced composite, the core material is made of a resin foam, and the covering material is made of a fiber reinforced resin material.
That is, the resin foam for forming a composite in the present embodiment (hereinafter also simply referred to as “resin foam”) serves as the core material and is used for forming a fiber-reinforced composite.
And the fiber reinforced composite of this embodiment has the fiber reinforced resin layer which consists of a fiber reinforced resin material in a surface layer part.
The fiber reinforced composite includes a thermoplastic resin in both the resin foam and the fiber reinforced resin material, and the resin foam and the fiber reinforced resin material are thermally fused at the contact interface. ing.

The resin foam for constituting the core material will be described below.
The resin foam is not particularly limited as long as it contains a thermoplastic resin. Examples of the thermoplastic resin include polyester resins, acrylic resins, polycarbonate resins, polymethacrylimide resins, and polyolefin resins. Etc.
The thermoplastic resin contained in the resin foam need not be one kind alone, and may be two or more kinds.
Moreover, the resin foam does not need to be comprised only by 1 or more types of thermoplastic resins, and may contain a small amount of rubber | gum, a thermosetting resin, etc. as needed.
The thermoplastic resin that is the main component of the resin foam is preferably a polyester resin or an acrylic resin in order to exhibit excellent mechanical strength and shock absorption in the fiber-reinforced composite to be produced.
Among them, the thermoplastic resin contained in the resin foam is more preferably a crystalline thermoplastic polyester resin because it can be used as a heat-resistant core material by increasing the crystallinity of the resin foam in the molding step. .
Here, the “main resin” means a resin contained in the resin foam in the highest mass ratio.

As the polyester resin, for example, a high molecular weight linear polyester obtained as a result of a condensation reaction between a dicarboxylic acid and a polyhydric alcohol can be employed.
Examples of the polyester resin include aliphatic polyester resins such as aromatic polyester resins and polylactic acid resins.

The aromatic polyester resin is usually a polyester containing an aromatic dicarboxylic acid component and a diol component, for example, polyethylene terephthalate resin, polypropylene terephthalate resin, polybutylene terephthalate resin, polycyclohexanedimethylene terephthalate resin, polyethylene naphthalate resin, Examples include polybutylene naphthalate resin.
The aromatic polyester resin contained in the resin foam of this embodiment is preferably a polyethylene terephthalate resin.
In addition, an aromatic polyester resin may be used independently or 2 or more types may be used together.

  In addition to the aromatic dicarboxylic acid component and the diol component, the aromatic polyester resin includes, for example, a tricarboxylic acid such as trimellitic acid such as trimellitic acid, a tetracarboxylic acid such as pyromellitic acid, or a polyvalent carboxylic acid such as tricarboxylic acid or its anhydride. Products, triols such as glycerin, and trihydric or higher polyhydric alcohols such as tetraols such as pentaerythritol may be contained as constituent components.

  Further, the aromatic polyester resin to be contained in the resin foam may be a recycled material collected and recycled from a used plastic bottle or the like.

The aromatic polyester resin to be contained in the resin foam may be partially crosslinked as long as it is within the range where thermoplasticity is exhibited.
Examples of the crosslinking agent for crosslinking an aromatic polyester resin such as polyethylene terephthalate resin include acid dianhydrides such as pyromellitic anhydride, polyfunctional epoxy compounds, oxazoline compounds, and oxazine compounds.
In addition, a crosslinking agent may be used independently or 2 or more types may be used together.

When the polyethylene terephthalate resin is crosslinked with a crosslinking agent, the crosslinking agent may be supplied together with the polyethylene terephthalate resin to the extruder and dynamically crosslinked in the extruder.
If the amount of the crosslinking agent supplied to the extruder is too small, the melt viscosity of the polyethylene terephthalate resin may be insufficient.
That is, if the amount of the cross-linking agent is too small, the melt viscosity of the polyethylene terephthalate resin after cross-linking is too low, and there is a risk that foam breakage is likely to occur during the formation of the resin foam.
On the other hand, if the amount of the crosslinking agent is too large, the melt viscosity of the polyethylene terephthalate resin becomes too high, and extrusion foaming may be difficult when the resin foam is produced by extrusion foaming.
Therefore, when the base resin of the resin foam for constituting the core material is a cross-linked polyethylene terephthalate resin, a cross-linking agent is used at a ratio of 0.01 to 5 parts by mass with respect to 100 parts by mass of the polyethylene terephthalate resin. It is preferable to employ a crosslinked one.
The ratio is more preferably 0.1 to 1 part by mass.

As the polylactic acid resin, a resin in which lactic acid is polymerized by an ester bond can be used.
When the thermoplastic resin contained in the resin foam is a polylactic acid-based resin, from the viewpoint of commercial availability and ease of imparting foamability, the polylactic acid-based resin contains D-lactic acid (D-form) and One or more selected from the group consisting of a copolymer of L-lactic acid (L-form), a homopolymer of either D-lactic acid or L-lactic acid, D-lactide, L-lactide and DL-lactide A ring-opening polymer of lactide is preferred.
In addition, polylactic acid-type resin may be used independently, or 2 or more types may be used together.

The polylactic acid-based resin may contain an aliphatic polyhydric alcohol or the like as a monomer component other than lactic acid.
Examples of the monomer component include aliphatic hydroxycarboxylic acids such as glycolic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, and hydroxyheptanoic acid; succinic acid, adipic acid, suberic acid, sebacic acid, and dodecanedicarboxylic acid. Aliphatic polycarboxylic acids such as succinic anhydride, adipic anhydride, trimesic acid, propanetricarboxylic acid, pyromellitic acid, pyromellitic anhydride; ethylene glycol, 1,4-butanediol, 1,6-hexanediol, Examples include 1,4-cyclohexanedimethanol, neopentyl glycol, decamethylene glycol, glycerin, trimethylolpropane, and pentaerythritol.

The polylactic acid-based resin may have a functional group such as an alkyl group, a vinyl group, a carbonyl group, an aromatic group, an ester group, an ether group, an aldehyde group, an amino group, a nitrile group, or a nitro group.
The polylactic acid-based resin may be crosslinked with an isocyanate-based crosslinking agent or the like, and may have a bond other than an ester bond in the main chain or side chain.

As the acrylic resin, one obtained by polymerizing a (meth) acrylic monomer can be employed.
Here, “(meth) acryl” is used as a term meaning both “acryl” and “methacryl”.

  The (meth) acrylic monomer is not particularly limited, and (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, lauryl (meth) acrylate, (meth ) 2-ethylhexyl acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, (meth) acrylamide and the like.

The acrylic resin contained in the resin foam may contain a monomer component copolymerizable with the above (meth) acrylic monomer.
Examples of such monomers include maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, crotonic acid, maleic amide, maleic imide, and the like.

When the resin foam is used as the core material and exhibits excellent adhesiveness with the fiber reinforced resin material, a high pressure can be applied to the fiber reinforced resin material at the time of heat fusion. It is preferable to be formed.
For these reasons, it is preferable that the resin foam be re-foamable by being heated at the time of heat-sealing.
More specifically, the resin foam is preferably in a state of exhibiting a dimensional change (volume increase) of + 20% or more when heated.
As described above, it is preferable that the resin foam has the ability to change the dimensions, as long as the resin foam is heat-sealed to the fiber-reinforced resin material. It is not necessary to have even the later resin foam.
In order to make the resin foam have such a volume change, for example, 0.1 to 5.0% by mass of a foaming agent described later may be left in the resin foam.
And when using as a core material as mentioned above, in order to make a high pressure act between fiber reinforced resin materials, the said resin foam is 0.1-0.1 in the reheating temperature which shows a + 20% dimensional change. It preferably exhibits an expansion pressure of 20 mN / mm ³ .
More preferably, the resin foam has a foaming force (expansion pressure) of 0.1 to 10 mN / mm ³ under the re-foaming conditions (temperature showing a dimensional change of 20%). Particularly preferred is 2 to 5 mN / mm ³ .
When the foaming power of the resin foam is too low, the fiber reinforced resin is subjected to sufficient pressure when charged in a mold together with the fiber reinforced resin material, for example, in order to perform heat fusion with the fiber reinforced resin material. There is a possibility that the material cannot be pressed toward the mold.
That is, if the foaming power of the resin foam is too low, the surface smoothness of the fiber reinforced resin material of the resulting fiber reinforced composite is lowered, the fiber reinforced resin material cannot be molded into a desired shape, and the core material (resin foam) There is a possibility that the mechanical strength of the fiber reinforced composite obtained by insufficient integration of the resin and the coating material (fiber reinforced resin material) will not be sufficient.
On the other hand, if the foaming power of the resin foam is too high than necessary, the pressing force of the resin foam on the inner surface of the mold of the fiber reinforced resin material becomes too large, and the thermoplastic resin contained in the fiber reinforced resin material Flows out of the mold more than necessary, and the fibers constituting the fiber reinforced resin material are easily exposed to the outside.
That is, if the foaming power of the resin foam is too high than necessary, the surface smoothness of the resulting fiber-reinforced composite decreases, the fiber-reinforced resin material cannot be molded into a desired shape, and the core material and the fiber-reinforced resin material There is a possibility that the mechanical strength of the fiber reinforced composite obtained by insufficient integration may be insufficient.

The foaming power of the resin foam can be adjusted by adjusting the crystallinity, apparent density, open cell ratio, etc. of the surface layer in addition to the method of adjusting the residual gas amount (foaming agent content) as described above. can do.
For example, a resin foam usually has a low foaming power by increasing the crystallinity of the surface layer, while a foaming power can be increased by reducing the crystallinity of the surface layer. .

  The foaming power of the resin foam is measured continuously using the universal testing machine used in "Foamed plastics-Hard material compression test" when the resin foam expands (foams) by heating. The minimum load detected in a predetermined time after the start of measurement is divided by the test piece volume (volume in the initial state).

Specifically, the foaming force can be determined as follows.
<How to find foaming power (expansion pressure)>
A cube-shaped test piece having a side of 50 mm is cut out from a position near the center of the resin foam.
When the thickness of the resin foam is less than 50 mm, a plurality of 50 mm square plate samples taken from a position close to the center of the resin foam are stacked to produce a cube-shaped test piece.
The measurement is carried out after the test piece is left for 24 hours or more in an environment of temperature 23 ± 2 ° C. and humidity 50 ± 5%. The measurement is performed using a universal testing machine, Tensilon-equipped high and low temperature thermostat and universal testing machine data processing software.
The test piece sandwiched between the upper compression plate and the lower compression plate expands from 50 mm (foaming) in a thermostat set to the temperature of the re-foaming condition of the resin foam (temperature indicating a dimensional change of 20%). Measure the load generated by doing this.
Measurement is performed continuously for 1800 seconds, and the value obtained by dividing the minimum load F (mN) measured between 600 seconds after the start of measurement and 1800 seconds by the test piece volume is foamed. Power.
In addition, the universal testing machine can use the apparatus marketed under the brand name "UCT-10T" from Orientec, for example.
As the Tensilon-related high and low temperature constant temperature bath, for example, T.I. S. E. A commercially available product can be used.
The universal testing machine data processing software can use what is marketed from UTPS-STD soft brain company.
The minimum load generated by the expansion during heating is calculated as follows for the three directions of the cube-shaped test piece in the vertical, horizontal, and height directions, and the lowest value among the minimum load values in the three directions is obtained as a sample. The foaming force (expansion pressure) of the resin foam can be obtained by dividing by the volume.

Foaming force (mN / mm ³ ) = Minimum load F (mN) / Volume of test piece (mm ³ )

To change the dimensions, first, a cube-shaped test piece having a side of 50 mm is cut out from a position near the center of the resin foam.
When the thickness of the resin foam is less than 50 mm, a plurality of 50 mm square plate samples taken from a position close to the center of the resin foam are stacked to produce a cube-shaped test piece.
The measurement is performed after leaving the test piece to stand for 24 hours or more in an environment of a temperature of 23 ± 2 ° C. and a humidity of 50 ± 5%.
The measurement is performed using a universal testing machine, Tensilon-equipped high and low temperature thermostat and universal testing machine data processing software.
Note that “temperature indicating a dimensional change of 20%” means that when a cube-shaped test piece with a side of 50 mm is heated to a uniform temperature as described above, a cube with a side of 60 mm is formed. It means a temperature exhibiting such volume expansion.
The heating at this time is usually carried out for 5 minutes.
Also, the temperature indicating the dimensional change is rounded down if the first digit is 4 or less, and rounded up if it is 5 or more.
Here, in the case where the test piece does not expand evenly in the vertical, horizontal, and height directions, the temperature at which the volume of the test piece expands 1.2 ³ (1.728) times is set as “heating dimension change”. It can be regarded as “the temperature at which the rate is 20%”.
Moreover, when confirming whether the resin foam exhibits a foaming force of 0.1 to 20 mN / mm ³ at a temperature at which the dimensional change of 20% is exhibited, the resin foam does not necessarily exhibit a dimensional change of 20%. There is no need to determine the temperature strictly, and the temperature at which the resin foam shows a dimensional change slightly lower than 20% and the temperature at which the resin foam shows a dimensional change slightly higher than 20% are obtained. The foaming force was measured as described above at both temperatures, and if these were both in the range of 0.1 to 20 mN / mm ³ , the resin foam had a temperature showing a dimensional change of 20%. Can also be considered to indicate a foaming power of 0.1 to 20 mN / mm ³ .

The resin foam preferably has a compressive strength of 10 kPa or more, more preferably 100 kPa or more, and particularly preferably 1000 kPa or more.
If the compressive strength of the resin foam is too low, the fracture stress of the fiber reinforced composite is reduced, and as a result, the impact absorbability of the fiber reinforced composite may be reduced.

The compressive strength of the resin foam can be controlled by adjusting the crystallinity of the surface layer of the resin foam, the apparent density of the resin foam, the residual gas amount, the open cell ratio, and the like.
For example, it is possible to increase the compressive strength of the resin foam by increasing the crystallinity of the surface layer of the resin foam, while reducing the crystallinity of the surface layer of the resin foam. The compressive strength of can be lowered.

The compressive strength of the resin foam refers to the compressive strength at 5% compression measured in accordance with the method described in JIS K7220: 1999 “Foamed plastic-hard material compression test”.
For example, the compressive strength can be obtained as follows.
<How to determine compressive strength>
A rectangular parallelepiped test piece having a length of 50 mm, a width of 50 mm, and a thickness of 25 mm is cut out from the resin foam.
When the thickness of the resin foam is less than 25 mm, a flat rectangular parallelepiped test piece is prepared by laminating a plurality of 25 mm square plate samples taken from a position close to the center of the resin foam.
The compressive strength can be determined by measuring the compressive strength of the test piece at 5% compression under the condition of a compression speed of 10 mm / min.

When the thermoplastic resin constituting the resin foam has crystallinity, if the crystallinity of the surface layer of the resin foam is too high, re-foaming at the time of thermal fusion with the fiber reinforced resin material Is inhibited, the fiber reinforced resin material cannot be pressed against the inner surface of the mold with sufficient pressure, so that the surface smoothness of the obtained fiber reinforced composite becomes insufficient, and the fiber reinforced resin material cannot be molded into a desired shape. There is a possibility that the mechanical strength of the fiber-reinforced composite obtained by insufficient integration of the core material and the covering material may be insufficient.
Therefore, the crystallinity of the surface layer of the resin foam is preferably less than 24%, more preferably less than 23%, and particularly preferably 10% or less.

When the thermoplastic resin constituting the resin foam has crystallinity, if the crystallinity of the inner layer of the resin foam is too high, re-foaming of the resin foam during the formation of the fiber-reinforced composite Is inhibited, the fiber reinforced resin material cannot be pressed against the inner surface of the mold with sufficient pressure, and the surface smoothness of the resulting fiber reinforced composite becomes insufficient, and the fiber reinforced resin material cannot be molded into a desired shape. There is a possibility that the mechanical strength of the fiber reinforced composite obtained by insufficient integration of the core material and the covering material may be insufficient.
From this, the crystallinity of the inner layer of the resin foam is preferably less than 24%. If it is too low, the resin foam becomes too soft and the fiber-reinforced resin material is applied to the inner surface of the mold by re-foaming. Since it may not be able to be pressed, 5 to 23% is preferable.

The surface layer of the resin foam means that the thickness of the resin foam in a direction perpendicular to the surface of the resin foam is “T (mm)” and the depth from the surface is 0.05 T (mm). Say part.
Further, the inner layer of the resin foam refers to the entire portion excluding the surface layer of the resin foam.

  The crystallinity of the surface layer and the inner layer of the resin foam is measured by the method described in JIS K7122: 1987 “Method for measuring the transition heat of plastic”.

In order to obtain the crystallinity, about 6 mg of a preferably rectangular parallelepiped sample cut out from the layer to be measured is collected, and thermal analysis is performed on this sample.
In addition, when a sample is cut out from the inner layer of the resin foam, in principle, the sample is cut out so as to include the center of gravity of the resin foam.

  Specifically, the crystallinity can be determined as follows.

(How to determine crystallinity)
Using a differential scanning calorimeter device (trade name “DSC6220 type” manufactured by SII Nano Technology Co., Ltd.), the sample was filled in the bottom of an aluminum measurement container so that there was no gap, and the sample was charged with a nitrogen gas flow rate of 30 mL / Hold at 30 ° C. for 2 minutes under conditions of minutes.
Thereafter, a DSC curve is obtained when the sample is heated from 30 ° C. to 290 ° C. at a rate of 10 ° C./min.
At that time, alumina is used as the reference material.
The crystallinity of the surface layer and the inner layer of the resin foam is the difference between the heat of fusion (mJ / mg) determined from the area of the melting peak and the heat of crystallization (mJ / mg) determined from the area of the crystallization peak. It is obtained gradually by the theoretical heat of fusion ΔH ₀ of the complete crystal of the thermoplastic resin.
For example, ΔH ₀ of polyethylene terephthalate is 140.1 mJ / mg.
The crystallinity of the layer to be measured for the resin foam is calculated based on the following formula.

Crystallinity of the layer to be measured for resin foam (%)
= 100 × (| heat of fusion (mJ / mg) | − | heat of crystallization (mJ / mg) |) / ΔH ₀ (mJ / mg)

  Separately, four resin foams are prepared, and the crystallinity of the surface layer and inner layer of each resin foam is measured in the same manner as described above, and the crystallization of each surface layer of five resin foams is performed. The arithmetic average value of the degree is the crystallinity of the surface layer of the resin foam, and the arithmetic average value of the crystallinity of the inner layer of each of the five resin foams is the crystallinity of the inner layer of the resin foam. .

  As a method for adjusting the crystallinity of the surface layer of the resin foam, for example, the crystallinity of the surface layer of the resin foam can be increased by slowing the cooling rate of the surface of the resin foam immediately after foaming. On the other hand, the crystallinity of the surface layer of the resin foam can be lowered by increasing the surface cooling rate of the resin foam immediately after foaming.

As a method for adjusting the crystallinity of the inner layer of the resin foam, for example, when the resin foam is manufactured by in-mold foam molding using synthetic resin foam particles described later, the inflow pressure of the heat medium into the mold is increased. Then, the degree of crystallinity of the inner layer of the resin foam can be increased by sufficiently heating the synthetic resin foam particles filled in the mold.
On the other hand, when producing a resin foam by in-mold foam molding, the pressure of the heat medium flowing into the mold is reduced to suppress the heating of the synthetic resin foam particles filled in the mold, thereby reducing the resin foam The crystallinity of the inner layer can be lowered.

If the heat dimensional change rate of the resin foam is too low, the fiber reinforced resin material cannot be pressed against the inner surface of the mold with sufficient pressure by re-foaming of the resin foam. Of fiber reinforced composites obtained when fiber reinforced resin materials cannot be molded into the desired shape or the integration of resin foam and fiber reinforced resin material is insufficient. Insufficient strength, air contained in the fiber reinforced resin material, and air existing in the gap between the fiber reinforced resin material and the inner surface of the mold are likely to remain, and the surface smoothness of the fiber reinforced composite is improved. There is a risk of becoming insufficient.
If the heating dimensional change rate of the resin foam is too high, the pressing force on the inner surface of the mold of the fiber reinforced resin material by the resin foam becomes too large, and the thermosetting resin impregnated in the fiber reinforced resin material or The thermoplastic resin flows out of the mold more than necessary, and the fibers constituting the fiber reinforced resin material are easily exposed to the outside, and the surface smoothness and mechanical strength of the resulting fiber reinforced composite are reduced. May cause a risk of failure.

The heating dimensional change rate of the resin foam can be controlled by adjusting the amount of the remaining foaming agent contained in the resin foam.
That is, the heating dimensional change rate of the resin foam can be increased by increasing the amount of the remaining foaming agent contained in the resin foam.

The apparent density of the resin foam is preferably 0.01~0.7g / cm ^3, more preferably 0.03~0.7g / cm ^3.
The density of the resin foam refers to a value measured according to JIS K7222: 2005 “Measurement of foamed plastic and rubber-apparent density”.

  If the apparent density of the resin foam is too low, the resin foam becomes too soft and the fiber reinforced resin material cannot be pressed against the inner surface of the mold by re-foaming of the resin foam. Mechanical properties of the fiber reinforced composite obtained when the surface smoothness of the composite is insufficient, the fiber reinforced resin material cannot be formed into a desired shape, and the integration of the resin foam and the fiber reinforced resin material is insufficient. There is a possibility that the strength may be insufficient.

  If the apparent density of the resin foam is too high, the flexibility of the resin foam will decrease, and it will not be possible to accurately re-foam the resin foam along the inner surface of the mold. The resin material cannot be pressed accurately and sufficiently along the inner surface of the mold, and the surface smoothness of the resulting fiber-reinforced composite becomes insufficient, and the resin foam and the fiber-reinforced resin material are integrated. There is a risk that the mechanical strength of the obtained fiber-reinforced composite becomes insufficient due to insufficient.

If the open cell ratio of the resin foam is too high, the thermoplastic resin contained in the fiber reinforced resin material is likely to penetrate into the inside, so that the fiber reinforced resin is used for good adhesion with the fiber reinforced resin material. There is a possibility that an excessive thermoplastic resin needs to be supported on the material.
In other words, if the open cell ratio of the resin foam is too high, it becomes easy to expose the fibers of the fiber reinforced resin material on the surface of the obtained fiber reinforced composite, and the surface smoothness of the fiber reinforced composite is insufficient. There is a risk of it.
Therefore, the open cell ratio of the resin foam is preferably less than 30%, more preferably 20% or less, and particularly preferably 10% or less.
In addition, the adjustment of the open cell ratio of the resin foam can be performed by adjusting the extrusion foaming temperature and the extruder when producing the synthetic resin particles when the resin foam is produced by foaming synthetic resin particles by the in-mold foam molding method. This can be done by adjusting the amount of blowing agent supplied.

Here, the open cell ratio of the resin foam is measured in the following manner based on the measurement method described in ASTM D-2856.
First, the apparent volume of the resin foam is measured to obtain an apparent volume V ₁ (cm ³ ).
Next, the actual sample volume V ₂ (cm ³ ) of the resin foam is measured by the 1-1 / 2-1 atmospheric pressure method using a volumetric air comparison type hydrometer.
In addition, the volume measurement air comparison type hydrometer can use what is marketed by Tokyo Science company by the brand name "1000 type | mold", for example.

Based on the apparent volume V ₁ (cm ³ ) of the resin foam and the actual sample volume V ₂ (cm ³ ) of the resin foam, the open cell ratio of the foam can be calculated by the following formula.
Open cell ratio (%) = 100 × (V ₁ −V ₂ ) / V ₁

The residual foaming agent in the resin foam is preferably one that is less likely to dissipate from the resin foam over time and that can easily exhibit a predetermined foaming force when the resin foam is heated.
Specifically, when the resin foam is mainly composed of a polyester resin or an acrylic resin, the remaining foaming agent is preferably normal butane, isobutane, carbon dioxide, or the like.
If the amount of the remaining foaming agent in the resin foam is too small, the fiber reinforced resin material cannot be pressed against the inner surface of the mold with sufficient pressure by re-foaming of the resin foam. Mechanical strength of the fiber reinforced composite obtained by insufficient smoothness on the material surface, inability to form the fiber reinforced resin material into the desired shape, and insufficient integration of the resin foam and the fiber reinforced resin material May cause the risk of insufficient.
From this, the amount of the remaining foaming agent in the resin foam is preferably 0.1% by mass or more, and more preferably 0.2% by mass or more.
However, if the amount of the remaining foaming agent in the resin foam is too large, the pressure applied to the inner surface of the fiber reinforced resin material by the resin foam becomes too large, and the thermoplastic contained in the fiber reinforced resin material. Since the resin flows out of the mold more than necessary, the fibers constituting the fiber reinforced resin material are easily exposed to the outside, and the surface smoothness of the resulting fiber reinforced composite may be reduced, It is preferable that it is 0.1-5 mass%, and it is more preferable that it is 0.5-3 mass%.

  The amount of the remaining foaming agent in the resin foam is, for example, a method in which the amount of the remaining foaming agent in the resin foam is increased by increasing the amount of the foaming agent to be mixed with the synthetic resin during the production of the resin foam by extrusion foaming. A method of increasing the amount of the remaining foaming agent in the resin foam by increasing the amount of the foaming agent impregnated in the synthetic resin foam particles used in the production of the resin foam by foam molding, a foaming agent in the resin foam A method of increasing the amount of residual foaming agent in the resin foam by further impregnation, a method of increasing the amount of residual foaming agent in the resin foam by reducing heating for foaming during the production of the resin foam, and resin foaming It can be controlled by a method such as a method of reducing the amount of residual foaming agent in the resin foam by providing a curing process such as placing the body under a heated atmosphere for a certain period of time.

The amount of residual foaming agent in the resin foam can be measured using a gas chromatograph.
Specifically, the residual foaming agent amount can be measured as follows when the foaming agent is a hydrocarbon such as butane.
<Measurement method of remaining amount of foaming agent>
A sample of 20 to 20 mg collected from the resin foam is precisely weighed, set at the decomposition furnace inlet of the pyrolysis furnace PYR-1A (manufactured by Shimadzu Corporation), and purged with a carrier gas (helium gas) for about 15 seconds. The mixed gas at the time is discharged.
After that, the sample is inserted into the core and heated to release the gas. This released gas is measured using a gas chromatograph manufactured by Shimadzu Corporation, and each standard gas calibration curve is used from the peak area of the obtained chromatograph. Then, the remaining foaming agent in the sample is quantified.
[Gas chromatograph conditions]
Measuring device: Gas chromatograph GC-14B (manufactured by Shimadzu Corporation)
Column: Polapack Q (80/100) 3 mmφ × 1.5 m (manufactured by GL Sciences Inc.)
Data processing device: C-R3A
Detector: TCD
Column temperature: 100 ° C
Inlet temperature: 120 ° C
Detector temperature: 120 ° C
Carrier gas: Helium carrier gas flow rate: 1 mL / min
[Heating furnace conditions]
Measuring device: Pyrolysis furnace PYR-1A (manufactured by Shimadzu Corporation)
Heating furnace temperature: 240 ° C
[Calculation conditions]
Calibration curve standard gas: i-butane, n-pentane calculation method: An analytical curve of i-butane and n-pentane was prepared in advance by the absolute calibration curve method, and the residual foaming agent amount of the obtained sample was determined for each standard gas. Calculated with a calibration curve. In the results, the amount of n-butane gas was converted into i-butane, and the amount of i-pentane gas was converted into n-pentane.

The method for producing the resin foam is not particularly limited, and a known production method can be used.
Specifically, as a method for producing a resin foam, for example, (1) the thermoplastic resin foam particles are filled in a mold, and the thermoplastic resin foam particles are heated with a heat medium such as hot water or steam. A method of producing a resin foam having a desired shape by fusing and fusing the foamed particles together by the foaming pressure of the thermoplastic resin foamed particles (in-mold foam molding method), (2) Extruding the thermoplastic resin A method of producing a resin foam by melt-kneading in the presence of a foaming agent such as a chemical foaming agent or a physical foaming agent and extrusion foaming from an extruder (extrusion foaming method), (3) a thermoplastic resin and A chemical foaming agent is supplied to an extruder and melt-kneaded at a temperature lower than the decomposition temperature of the chemical foaming agent to produce a foamable resin molded body from the extruder, and the foamable resin molded body is foamed to produce a resin foam. Method, (4) Bulk weight containing chemical foaming agent After the body is manufactured, a method of manufacturing a resin foam by heating and foaming (bulk foaming method), (5) Mixing a monomer and a foaming agent with a mixing head or the like to produce a mixture, and then discharging the mixture to polymerize There is a method of producing a resin foam by taking out from the mold after foaming, injecting the mixture into the mold to produce a foam, and completing the polymerization reaction and the foaming step.
Among these, the in-mold foam molding method (1) is preferable because the resin foam can be easily produced in a desired shape.

  As a method for producing the thermoplastic resin foam particles used in the above-mentioned in-mold foam molding method (1), (1) the thermoplastic resin is supplied into an extruder, melt-kneaded in the presence of a physical foaming agent and extruded. A method for producing thermoplastic resin foam particles by cutting while extruding a thermoplastic resin extrudate from a nozzle mold attached to the machine and then cooling it, and (2) supplying a thermoplastic resin into the extruder and a physical foaming agent. Is produced by melt-kneading and extruding from a nozzle die attached to an extruder to produce a strand-like thermoplastic resin extrudate, and cutting the thermoplastic resin extrudate at predetermined intervals (3) Supplying a thermoplastic resin into an extruder, melt-kneading in the presence of a physical foaming agent, and extrusion-foaming from an annular die or T-die attached to the extruder to obtain a foamed sheet Manufacture this foam A method for producing foamed thermoplastic resin particles by cutting a sheet, (4) after producing thermoplastic resin particles by suspension polymerization or the like, and producing foamable particles impregnated with a foaming agent by an autoclave or the like, A method of producing foamed thermoplastic resin particles by heating and foaming using a pre-foaming machine capable of supplying a heat medium such as water vapor; (5) supplying the thermoplastic resin into the extruder and melt-kneading and attaching to the extruder Extruded from a nozzle mold to produce a strand-shaped thermoplastic resin extrudate, cut the thermoplastic resin extrudate at predetermined intervals to produce thermoplastic resin particles, and impregnate the foaming agent with an autoclave or the like. Examples thereof include a method of producing foamed thermoplastic resin particles by producing foamable particles, followed by heating and foaming using a preliminary foaming machine capable of supplying a heat medium such as water vapor.

Next, an example of a method for producing the thermoplastic resin expanded particles will be described.
First, an example of a production apparatus used when producing thermoplastic resin expanded particles by extrusion foaming will be described with reference to the drawings.
Here, FIG. 1 shows how thermoplastic resin foam particles such as polyester resin particles containing a foam material are produced using an extruder and a nozzle mold 1 attached to the front end of the extruder. Is.
As shown in FIG. 2, a plurality of nozzle outlet portions 11, 11... Are formed on the same virtual circle A at equal intervals on the front end surface 10 of the nozzle mold 1.

  In the portion surrounded by the nozzle outlet portions 11, 11,... On the front end face 10 of the nozzle mold 1, the rotary shaft 2 is disposed in a state of protruding forward, and this rotary shaft. 2 is connected to a driving member 3 such as a motor through a front portion 41a of a cooling drum 41 constituting a cooling member 4 described later.

Further, one or a plurality of rotary blades 5, 5... Are integrally provided on the outer peripheral surface of the rear end portion of the rotary shaft 2, and all the rotary blades 5 are nozzles when rotating. The front end surface 10 of the mold 1 is always in contact.
When the plurality of rotary blades 5, 5,... Are integrally provided on the rotary shaft 2, the plurality of rotary blades 5, 5,. Each is arranged.
2 shows a case where four rotary blades 5, 5,... Are integrally provided on the outer peripheral surface of the rotary shaft 2 as an example.

  As the rotary shaft 2 rotates, the rotary blades 5, 5... Are always in contact with the front end surface 10 of the nozzle mold 1, and nozzle outlet portions 11, 11. It moves on the virtual circle A, and the polyester-based resin extruded foam extruded from the outlet portions 11, 11.

A cooling member 4 is disposed so as to surround at least the front end of the nozzle mold 1 and the rotating shaft 2.
The cooling member 4 has a front circular front part 41a having a diameter larger than that of the nozzle mold 1 and a cylindrical peripheral wall part 41b extending rearward from the outer peripheral edge of the front part 41a. A bottom cylindrical cooling drum 41 is provided.

Further, a supply port 41c for supplying the coolant 42 is formed in a portion of the peripheral wall portion 41b of the cooling drum 41 corresponding to the outside of the nozzle mold 1 so as to penetrate between the inner and outer peripheral surfaces. Yes.
A supply pipe 41 d for supplying the coolant 42 into the cooling drum 41 is connected to the outer opening of the supply port 41 c of the cooling drum 41.

The coolant 42 is configured to be supplied obliquely forward along the inner peripheral surface of the peripheral wall portion 41b of the cooling drum 41 through the supply pipe 41d.
Then, the cooling liquid 42 spirals along the inner peripheral surface of the peripheral wall portion 41b of the cooling drum 41 by the centrifugal force accompanying the flow velocity when being supplied from the supply pipe 41d to the inner peripheral surface of the peripheral wall portion 41b of the cooling drum 41. Go forward as you draw.
Then, the coolant 42 gradually spreads in the direction perpendicular to the traveling direction while traveling along the inner peripheral surface of the peripheral wall portion 41b, and as a result, the inner surface of the peripheral wall portion 41b in front of the supply port 41c of the cooling drum 41 is increased. The peripheral surface is configured to be entirely covered with the coolant 42.

  The cooling liquid 42 is not particularly limited as long as the polyester resin foamed particles can be cooled, and examples thereof include water, alcohol, and the like, but water is preferable in consideration of treatment after use.

A discharge port 41e is formed on the lower surface of the front end portion of the peripheral wall portion 41b of the cooling drum 41 so as to penetrate between the inner and outer peripheral surfaces.
A discharge pipe 41f is connected to the outer opening of the discharge port 41e.
The polyester-based resin foam particles and the cooling liquid 42 can be continuously discharged through the discharge port 41e.

  A nozzle metal attached to the front end of the extruder after supplying the thermoplastic resin and preferably a crosslinking agent to the extruder and melt-kneading in the presence of a foaming agent to crosslink the thermoplastic resin preferably with the crosslinking agent The extruded foam obtained by extruding and foaming the thermoplastic resin from the mold 1 can be cut by the rotary blade 5 to produce thermoplastic resin particles.

Examples of the chemical foaming agent include azodicarbonamide, dinitrosopentamethylenetetramine, hydrazoyl dicarbonamide, sodium bicarbonate, and the like.
In addition, a chemical foaming agent may be used independently or 2 or more types may be used together.

Examples of the physical blowing agent include saturated aliphatic hydrocarbons such as propane, normal butane, isobutane, normal pentane, isopentane and hexane, ethers such as dimethyl ether, methyl chloride, 1,1,1,2-tetrafluoroethane. Chlorofluorocarbons such as 1,1-difluoroethane and monochlorodifluoromethane, carbon dioxide, nitrogen and the like, dimethyl ether, propane, normal butane, isobutane and carbon dioxide are preferable, propane, normal butane and isobutane are more preferable, normal butane, Isobutane is particularly preferred.
In addition, a physical foaming agent may be used independently or 2 or more types may be used together.

The fiber reinforced resin material partially or entirely laminated on the surface of the resin foam is not particularly limited to fibers that can be formed, and examples thereof include glass fibers, carbon fibers, and silicon carbide fibers. Inorganic fiber such as alumina fiber, Tyranno fiber, basalt fiber, ceramic fiber; metal fiber such as stainless steel fiber and steel fiber; organic fiber such as aramid fiber, polyethylene fiber, polyparaphenylene benzoxador (PBO) fiber; boron fiber Etc.
Especially, since the fiber of a fiber reinforced resin material has the outstanding mechanical strength and heat resistance, a carbon fiber, a glass fiber, and an aramid fiber are preferable, and a carbon fiber is more preferable.

The fiber is preferably used for forming a fiber-reinforced resin material as a reinforcing fiber base processed into a desired shape.
Examples of the reinforcing fiber base material include woven fabrics, knitted fabrics, nonwoven fabrics, and face materials formed by binding (stitching) fiber bundles (strands) in which reinforcing fibers are aligned in one direction.
Examples of the weaving method include plain weave, twill weave and satin weave.

The reinforcing fiber substrate may be used without laminating only one reinforcing fiber substrate, or a plurality of reinforcing fiber substrates may be laminated and used as a laminated reinforcing fiber substrate.
As a laminated reinforcing fiber base material in which a plurality of reinforcing fiber base materials are laminated, (1) a plurality of reinforcing fiber base materials of only one kind are prepared, and a laminated reinforcing fiber base material in which these reinforcing fiber base materials are laminated, 2) A plurality of types of reinforcing fiber base materials are prepared, a laminated reinforcing fiber base material obtained by laminating these reinforcing fiber base materials, and (3) a fiber bundle (strand) in which the reinforcing fibers are aligned in one direction is bound with a thread ( A plurality of reinforcing fiber base materials prepared by stitching) are prepared, and these reinforcing fiber base materials are superposed so that the fiber directions of the fiber bundles are different from each other. A laminated reinforcing fiber base material integrated (stitched) with is used.
Examples of the yarn include synthetic resin yarns such as polyamide resin yarns and polyester resin yarns, and stitch yarns such as glass fiber yarns.

In the laminated reinforcing fiber substrate of (1) above, in the case of a laminated reinforcing fiber substrate formed by laminating a plurality of woven fabrics, the length direction of the warp (weft) constituting each woven fabric is from the plane direction of the woven fabric. It is preferable that they are arranged radially.
Specifically, as shown in FIGS. 3 and 4, when the length directions of the warps (wefts) constituting each woven fabric are 1a, 1b,..., The lengths of these warps (wefts) It is preferable that the length directions 1a, 1b... Are arranged radially, and the length direction 1a of any warp (weft) of the length directions 1a, 1b. More preferably, the length directions 1b, 1c,... Of other warps (wefts) are arranged in line symmetry with respect to the length direction 1a of a specific warp (weft).

  Further, the crossing angle between the length directions 1a, 1b,... Of the warps (wefts) constituting each woven fabric is substantially the same in any direction without the strength of the fiber reinforced resin material being biased in one direction. Since strength can be imparted, 90 ° is preferable when two woven fabrics are overlapped, and 45 ° is preferable when three or more woven fabrics are overlapped.

In the laminated reinforcing fiber base material of the above (2), it is preferable that the length direction of the fibers of the fiber bundle constituting each fiber base material is arranged radially when viewed from the plane direction of the fiber base material.
Specifically, as shown in FIG. 3 and FIG. 4, when the length directions of the fibers of the fiber bundle constituting each fiber base are 1a, 1b. It is preferable that the directions 1a, 1b,... Are arranged radially, and when the arbitrary length direction 1a of the fiber length directions 1a, 1b,. It is more preferable that the other length directions 1b, 1c,... Are arranged so as to be line symmetric with respect to the center.

  Moreover, the crossing angle of the fiber length direction 1a, 1b ... of the fiber bundle which comprises each fiber base material is substantially the same in arbitrary directions, without the intensity | strength of a fiber reinforced resin material being biased to one direction. Since mechanical strength can be imparted, 90 ° is preferable when two fiber substrates are stacked, and 45 ° is preferable when three or more fiber substrates are stacked.

As the fiber reinforced resin material, for example, a material obtained by impregnating a reinforced fiber base material with a thermoplastic resin can be employed.
By impregnating the thermoplastic resin, the reinforcing fibers are bonded and integrated, and the fiber-reinforced resin material usually has a strength superior to that of the reinforcing fiber substrate alone or the resin alone.
The thermoplastic resin impregnated into the reinforcing fiber is not particularly limited, and examples thereof include olefin resins, polyester resins, thermoplastic epoxy resins, amide resins, thermoplastic polyurethane resins, sulfide resins, and acrylic resins.
Polyester resins and thermoplastic epoxy resins are preferred because they are excellent in adhesiveness with the resin foam or adhesiveness between the reinforcing fibers constituting the fiber-reinforced resin material.
The main resin of the fiber reinforced resin material may be a thermoplastic elastomer such as a thermoplastic polyurethane resin for the reason described later.
Here, the “main resin” of the fiber reinforced resin material means a resin contained in the highest mass ratio in a portion excluding the reinforced fiber.
In addition, a thermoplastic resin may be used independently or 2 or more types may be used together.

The thermoplastic epoxy resin may be a polymer or copolymer of epoxy compounds having a linear structure, or a copolymer of an epoxy compound and a monomer that can be polymerized with the epoxy compound. And a copolymer having a linear structure.
Specifically, as the thermoplastic epoxy resin, for example, bisphenol A type epoxy resin, bisphenol fluorene type epoxy resin, cresol novolac type epoxy resin, phenol novolac type epoxy resin, cyclic aliphatic type epoxy resin, long chain aliphatic type An epoxy resin, a glycidyl ester type epoxy resin, a glycidylamine type epoxy resin and the like can be mentioned, and a bisphenol A type epoxy resin and a bisphenol fluorene type epoxy resin are preferable.
In addition, a thermoplastic epoxy resin may be used independently or 2 or more types may be used together.

Examples of the thermoplastic polyurethane resin include a polymer having a linear structure obtained by polymerizing diol and diisocyanate.
Examples of the diol include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, and the like.
Diols may be used alone or in combination of two or more.
Examples of the diisocyanate include aromatic diisocyanate, aliphatic diisocyanate, and alicyclic diisocyanate. Diisocyanate may be used independently or 2 or more types may be used together. In addition, a thermoplastic polyurethane resin may be used independently or 2 or more types may be used together.

Examples of the polyamide resin include hexamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2,2,4- or 2,4,4-trimethylhexamethylenediamine, 1,3- or 1,4-bis (aminomethyl). Aliphatic, alicyclic and aromatic diamines such as cyclohexane, bis (p-aminocyclohexylmethane), m- or p-xylylenediamine and adipic acid, suberic acid, sebacic acid, cyclohexanedicarboxylic acid, terephthalic acid Polyamide resins produced from aliphatic, alicyclic, aromatic and other dicarboxylic acids such as isophthalic acid, and aminocarboxylic acids such as 6-aminocaproic acid, 11-aminoundecanoic acid and 12-aminododecanoic acid Of manufactured polyamide resin, ε-caprolactam, ω-dodecalactam Examples thereof include, but are not limited to, polyamide resins produced from such lactams, copolymerized polyamide resins composed of these components, and mixtures of these polyamide resins.
Specifically, polycoupleramide (polyamide 6), polydodecanoamide (polyamide 12), polyhexamethylene adipamide (polyamide 6 · 6), polyhexamethylene azelamide (polyamide 6 · 9), polyhexamethylene sebaca Amide (polyamide 6 · 10), polyhexamethylene dodecanoamide (polyamide 6 · 12), polyxylylene adipamide, polyhexamethylene terephthalamide, polyphenylene phthalamide, polyamide 6/6 · 6, poly (xylylene) Adipamide / hexamethylene adipamide) and the like.

The fiber reinforced resin material may contain a thermosetting resin together with the thermoplastic resin.
The thermosetting resin is not particularly limited. For example, epoxy resin, unsaturated polyester resin, phenol resin, melamine resin, polyurethane resin, silicon resin, maleimide resin, vinyl ester resin, cyanate ester resin, maleimide resin and cyanide Examples include resins obtained by prepolymerization of acid ester resins, and epoxy resins and vinyl ester resins are preferred because of excellent heat resistance, elastic modulus, and chemical resistance.
In addition, a thermosetting resin may be used independently or 2 or more types may be used together.

The reinforcing resin content in the fiber reinforced resin material is preferably 20 to 70% by mass, and more preferably 30 to 60% by mass.
If the content of the reinforcing resin is too small, the adhesiveness between the reinforcing fibers and the adhesiveness between the fiber-reinforced resin layer and the core material become insufficient, and the mechanical strength of the fiber-reinforced plastic layer and the fiber-reinforced composite There is a possibility that the mechanical strength or the shock absorption cannot be sufficiently improved.
Moreover, when there is too much content of resin for reinforcement | strengthening, the mechanical strength of a fiber reinforced resin layer falls and there exists a possibility that the mechanical strength of a fiber reinforced composite body cannot fully be improved.

The thickness of the fiber reinforced resin material is preferably 0.02 to 2 mm, and more preferably 0.05 to 1 mm.
A thermoplastic resin fiber reinforcing material having a thickness within the above range is excellent in mechanical strength despite being lightweight.

Basis weight of the fiber-reinforced resin material is preferably ^{50~4000g / m 2, 100~1000g / m} 2 is more preferable.
When the basis weight of the fiber reinforced resin material is within the above range, the fiber reinforced composite can be in a state where the fiber reinforced resin layer is lightweight and excellent in strength.

  The method of impregnating the fiber reinforced resin material with the synthetic resin is not particularly limited. For example, (1) a method of immersing the fiber base material in the synthetic resin and impregnating the fiber base material with the synthetic resin; 2) A method of applying a synthetic resin to the fiber base material and impregnating the fiber base material with the synthetic resin is exemplified.

In addition, the said fiber base material and the fiber reinforced resin material by which this fiber base material is impregnated with a thermoplastic resin can use what is marketed.
Examples of the fiber base material include those commercially available from Mitsubishi Rayon under the trade name “Pyrofil”.
Examples of the fiber reinforced resin material include those commercially available from Nagase Chemtech under the trade name “NNGF60-03s”.

In order to manufacture the fiber reinforced composite, as shown in FIG. 5, a fiber reinforced resin material 7 is laminated on the surface of the resin foam 6 to form a laminate M, and the resin foam 6 and the fiber reinforced resin are formed. A step of heat-sealing the material 7 (lamination step) is performed.
In the laminating step, only the surface layer portion of the resin foam is selectively heated, and the foam heating step of heating the surface of the resin foam to a temperature higher than the central portion of the resin foam, and the fiber reinforced resin material After performing the heating process of the fiber reinforcing material to be heated, a fusing process is performed in which the heating surface of the resin foam and the heating surface of the fiber reinforced resin material are brought into contact with each other with a predetermined pressure to thermally bond them.

The foam heating step and the fiber reinforcement heating step can be performed using a heating device such as a heater.
As a heating device used in the fiber reinforcing material heating step and the foam heating step, for example,
Infrared heaters, carbon heaters, hot air dryers, heating plates, etc. can be used.
Here, in order to selectively heat only the surface of the resin foam in the foam heating step, it is preferable to use a heating plate.
The heated fiber reinforced resin material is used as a heating plate, the fiber reinforced resin material is laminated on the resin foam, and only the surface of the resin foam is selectively heated by heat transfer from the fiber reinforced resin material. You may make it make it.

When this fiber reinforced resin material is used as a heating plate, there is no need to provide a special device for the foam heating process.
In this case, the fiber reinforced resin material is heated to a temperature higher than that capable of heat-sealing with the resin foam, and a predetermined pressure or more is applied between the fiber reinforced resin material and the resin foam. Thus, the fusing step can be performed simultaneously with the foam heating step.
Therefore, when the fiber reinforced resin material is used as a heating plate, it is possible to prevent an apparatus required for manufacturing the fiber reinforced composite from becoming large and simplify the manufacturing process of the fiber reinforced composite.

For example, in the fusing step, first, the fiber reinforced resin material in a heated state is laminated on the resin foam to prepare a pre-laminated body, and then the pre-laminated body corresponds to the product shape of the fiber reinforced composite. It is possible to adopt a method in which the fiber reinforced resin material and the resin foam are heat-sealed under a pressurized condition by setting the mold with an internal space and applying pressure to the preliminary laminate with the mold.
Thereby, in the fusion process, a fiber reinforced composite shaped by the mold is produced.
In the heat fusion in the mold, the resin foam is heated to a predetermined temperature or more to cause volume expansion of the resin foam, and the pressure due to the volume expansion is applied to the resin foam and the fiber reinforced resin material. It is preferable to use it for heat fusion.
In this preferable embodiment, an advantage that a fiber-reinforced composite in which the mold shape is faithfully reflected can be easily obtained can be exhibited.
If excessive heat is applied to the resin foam before heat fusion in the mold, the expansion force is consumed at this point, and it is difficult to generate sufficient pressure during heat fusion in the mold. There is.
Therefore, the temperature at which the heating dimensional change rate of the resin foam is + 5% is T ₅ (° C.), and the temperature at which the heating dimensional change rate of the resin foam is + 20% is T ₂₀ (° C.). In some cases, the preliminary laminate has a temperature “Tc (° C.)” of at least a central portion of the resin foam that is 10 ° C. or more lower than “T ₅ (° C.)” (Tc ≦ (T ₅ −10)). It is preferable to adjust the temperature of the resin foam so that
When the fiber reinforced resin material and the resin foam are heat-sealed in the mold, the temperature “Tc (° C.)” of the center of the resin foam is equal to or higher than “T ₂₀ (° C.)” (Tc ≧ T ₂₀ ). It is preferable to adjust the temperature of the resin foam so that the resin foam exhibits a sufficient expansion pressure.

The fusion process can be performed in parallel with a molding process in which a desired shape is imparted to the fiber-reinforced composite by a pressure device.
A general hot press can be adopted as the pressurizing device.
That is, the fusion process can be performed using, for example, a hot press apparatus as shown in FIG.
In the molding process using the hot press apparatus as shown in FIG. 6, for example, a laminate M is prepared by laminating a sheet-like fiber reinforced resin material around a prismatic resin foam, and the laminate M After the laminated body M is disposed in the female mold Bx having a slightly larger internal space, the upper opening of the internal space of the female mold Bx is closed with the male mold By using these molds B to heat up and down the heat press. The fiber reinforced composite can be produced by sandwiching the plates P1 and P2 and applying pressure to the laminate M through the mold.
When the compression stress of the resin foam at a temperature equal to or lower than the glass transition point of the main resin foam is “A (MPa)”, the fiber reinforced composite is “A ± 1 (MPa)”. The laminated body M is press-molded in the range, and hot press is performed so that the apparent density in the range from the laminated interface of the fiber reinforced resin material to the depth of 2 mm is 0.1 to 1.5 g / cm ^3. It is preferable to be manufactured.
About the pressure at the time of press-molding the laminated body M of the fiber reinforced resin material and the resin foam, it is determined with reference to the compressive stress of the resin foam below the glass transition temperature of the main resin of the resin foam. Is preferred.
If the glass transition temperature of the main resin of the resin foam is too low, the fiber reinforced resin material will be rapidly cooled and the surface properties will deteriorate, and if it is too high, it will take time to cool the fiber reinforced resin material and the production cycle will be long. Since it falls, it is preferable that it is 40-150 degreeC, and 50-100 degreeC is more preferable.
If the pressure at the time of press molding is too low, the integrity of the fiber-reinforced resin material and the resin foam will be low, and if it is too high, the resin foam will be compressed and it may not be possible to obtain the desired molded product Have
Therefore, the press molding pressure is preferably within a predetermined range with respect to the compression stress (A), specifically, preferably within a range of 0.1 MPa to (A + 1 MPa), and 0.2 MPa. It is particularly preferable to be within the range of ~ (A + 0.8 MPa).
In addition, it can replace with the method using such a hot press, for example, can implement using an autoclave type pressurizing apparatus as shown in FIG.
In the molding process as shown in FIG. 7, for example, a laminate M is prepared by laminating a sheet-like fiber reinforced resin material around a prismatic resin foam, and a cavity slightly larger than the laminate M is prepared. After disposing the laminate M on the mold B having B1, the cavity B1 is closed, and the release film C is wrapped around the outer surface of the mold B so as to surround the mold B, and then released. Further, a breather cloth D is wound on the film C, and this is accommodated in a bagging bag E, in which the space H in the bagging film is decompressed and the space in the autoclave outside the bagging film is pressurized. By doing so, the fiber reinforced composite can be formed into a prismatic shape.
At this time, for example, if the fiber-reinforced resin material is heated in advance, the molding step and the fusing step can be performed in parallel.

The foam heating process using a fiber reinforced resin material as a heating plate depends on the material of the resin foam, but the resin foam is made of polyethylene terephthalate resin, and the melting point of the polyethylene terephthalate resin is set to “Tm (° C.)”. ", The heating temperature of the resin foam by the fiber reinforced resin material is preferably in the range of (Tm + 5) ° C to (Tm + 100) ° C.
At this time, a fiber reinforced resin material having a surface temperature exceeding the melting point of the polyethylene terephthalate resin forming the resin foam is brought into contact with the resin foam, and a pressure is applied between the fiber reinforced resin material and the resin foam. These are heat-sealed by adding.
In the heat sealing, it is possible to prevent the entire resin foam from being compressed due to contact with the fiber reinforced resin material, and to apply a strong pressure to the contact surface between the fiber reinforced resin material and the resin foam. preferable.
Accordingly, the temperature of the resin foam is such that the temperature “Tc (° C.)” of the resin foam is equal to or higher than “T ₂₀ (° C.)” (Tc ≧ T ₂₀ ). It is preferable to make the resin foam exhibit a sufficient expansion pressure by adjusting.
When the resin foam is made of an acrylic resin and the glass transition temperature of the acrylic resin is “Tg2 (° C.)”, the thermal fusion is performed by setting the temperature of the surface of the resin foam to (Tg2 + 50) ° C. It is preferable to carry out at ~ (Tg2 + 150) ° C.

In addition, about the glass transition temperature and melting | fusing point (exothermic peak temperature) here, the value measured by the method described in JISK7121: 1987 "Plastic transition temperature measuring method" is intended.
However, the sampling method and temperature conditions are as follows.
Using a differential scanning calorimeter device, about 6 mg of the sample is filled so that there is no gap at the bottom of the aluminum measurement container, and the sample is cooled from 30 ° C. to −40 ° C. for 10 minutes under a nitrogen gas flow rate of 20 mL / min. The sample was heated from -40 ° C. to 290 ° C. (1st Heating), held at 290 ° C. for 10 minutes, and then cooled from 290 ° C. to −40 ° C. (Cooling) for 10 minutes. Then, the temperature is raised from −40 ° C. to 290 ° C. (2nd Heating) to obtain a DSC curve.
In addition, all the temperature increase rates and temperature decrease rates are performed at 10 ° C./min, and alumina is used as a reference material.
The inflection point of the obtained curve is defined as the glass transition temperature, and the temperature at the top of the exothermic peak is defined as the exothermic peak temperature (melting point).
As the differential scanning calorimeter, for example, a differential scanning calorimeter marketed by SII Nano Technology Co., Ltd. under the trade name “DSC6220 type” can be used.

When trying to heat the surface of the resin foam under the above temperature conditions, it is usually necessary to heat the fiber reinforced resin material to the same temperature.
If a resin having an excessively low viscosity at the above temperature is selected as the thermoplastic resin contained in the fiber reinforced resin material, the fibers of the fiber reinforced resin material may be exposed on the surface during the fusing process.
For example, when the fiber reinforced resin material and the resin foam are fused by the method shown in FIG. 6, when the thermoplastic resin contained in the fiber reinforced resin material has a low viscosity, this thermoplasticity Most of the resin is discharged to the outside of the fiber reinforced resin material, and the fiber reinforced resin layer after heat fusion may be in a state where the thermoplastic resin is insufficient.
For this reason, the thermoplastic resin contained in the fiber reinforced resin material is more than a certain amount in the temperature condition necessary for heating the surface of the resin foam made of polyester resin or acrylic resin to the above temperature. It is preferable to have a viscosity.
The thermoplastic resin contained in the fiber reinforced resin material is preferably a thermoplastic elastomer in that it exhibits a higher viscosity than a general polyester resin or acrylic resin in such a high temperature range.
Among them, the thermoplastic elastomer contained in the fiber reinforced resin material is preferably a thermoplastic polyurethane resin in consideration of the case where the resin foam is made of a polyester resin or an acrylic resin, and considering the affinity for these resins.

In addition, since the said thermoplastic polyurethane resin shows high viscosity also at high temperature as mentioned above, it is difficult to fully impregnate a reinforced fiber base material at the time of formation of a fiber reinforced resin material.
That is, the fiber-reinforced resin material containing the thermoplastic polyurethane resin is easy to contain bubbles.
The air bubbles in the fiber reinforced resin material can cause air pockets to be formed at the interface between the fiber reinforced resin material and the mold B during molding by the autoclave.
Since this air pool may cause problems such as poor appearance and insufficient strength for the fiber reinforced composite obtained, the pressing force from the resin foam side is applied to the fiber reinforced resin material at the time of molding. It is preferable to make it act sufficiently.

As described above, when heat-bonding in a mold, in order to obtain a fiber-reinforced composite having excellent external accuracy, the expansion pressure of the resin foam is used for heat-bonding between the resin foam and the fiber-reinforced resin material. It is preferable to use it.
Therefore, it is preferable that the resin foam used for the production of the fiber reinforced composite has an ability to expand at a predetermined ratio at least in the initial state, and the predetermined ratio immediately before the heat fusion in the mold. It is preferable to have the ability to expand.
That is, the resin foam is preferably in a state of increasing in volume at a rate of 5% by volume / min or more when heated, and preferably in a state of increasing in volume at a rate of 10% by volume / min or more. More preferred.

The increase in the volume of the resin foam can be determined, for example, by heating a test piece cut out from the resin foam at a constant temperature for a certain time and dividing the volume change before and after the heating by a unit time.
The said test piece can be made into the cube whose length of one side cut out from the center part of the resin foam is 20 mm, for example.
The heating time of the test piece can be, for example, 2 minutes, and the heating device can be a constant temperature drier marketed by Yamato Scientific Co., Ltd. under the trade name “DN44”.
The volume of the test piece before and after heating is preferably measured after the test piece is left to stand for 24 hours in an environment of 23 ° C. and a relative humidity of 60% in order to eliminate the influence of the measurement conditions.

The resin foam is 0.1 to 20 mN / mm at a heating temperature exhibiting a dimensional change of 20% in order to apply a high pressure between the resin foam and the fiber reinforced resin material at the time of thermal fusion with the fiber reinforced resin material. An expansion pressure of ³ is preferred.
In other words, when the resin foam is heated so that no pressure is applied to the resin foam, the temperature at which the resin foam expands and exhibits a dimensional change of 20% or more is referred to as “T ₂₀ (° C.)”. In this case, it is preferable to heat the surface of the resin foam to which the fiber-reinforced resin material is heat-sealed to “T ₂₀ (° C.)” or more at the time of molding by the hot press or the like.

After the heat fusion, a cooling step for cooling the thermoplastic fiber reinforced composite is performed.
If the thermoplastic fiber reinforced composite has an excessively high extraction temperature, it may be difficult to give a predetermined shape due to further foaming or shrinkage after the extraction.
Therefore, when the glass transition temperature of the thermoplastic fiber reinforced composite foamed molded article is Tgx (° C.), the fiber reinforced composite is cooled so that the mold temperature is (Tgx−10 ° C.) or less. It is preferable.
That is, it is preferable to take out the fiber-reinforced composite after heat sealing from the mold in a state where at least the surface is cooled to a temperature of (Tgx-10 ° C.) or lower.
The surface temperature at the time of taking out the fiber reinforced composite from the mold can be measured by applying a measurement probe of a contact thermometer to the surface of the fiber reinforced composite immediately after taking out. It can be obtained as an average value of measured values obtained at a plurality of locations (for example, about 10 locations) on the surface.

Further, in the present embodiment, heat fusion between the resin foam and the fiber reinforced resin material is performed in a state where the center of the resin foam is at a lower temperature than the surface.
Therefore, the core material of the obtained fiber reinforced composite is relatively stable in the direction from the center to the lamination interface with the fiber reinforced resin layer up to a certain area of the shape of the bubble, and near the lamination interface. The state suddenly changes to a laterally spread state.
That is, when heat fusion between the resin foam and the fiber reinforced resin material is performed in a state where sufficient heating is performed up to the center, the pressure at the time of the heat fusion easily acts near the center of the resin foam, The core material of the obtained fiber reinforced composite will change the shape of the bubbles to spread laterally at an early stage in the direction from the center to the lamination interface with the fiber reinforced resin layer.
In contrast, the fiber-reinforced composite of the present embodiment has a relatively stable bubble shape up to the vicinity of the lamination interface as described above, and the shape is greatly varied in the vicinity of the lamination interface.
For this reason, the fiber reinforced composite of this embodiment exhibits excellent properties in strength and the like.

  In the present embodiment, the fiber reinforced composite and the manufacturing method thereof are exemplified as described above, but the fiber reinforced composite and the manufacturing method of the present invention are not limited to the above examples, and Various modifications can be made to the examples.

EXAMPLES Next, although an Example is given and this invention is demonstrated in more detail, this invention is not limited to these.
(Example 1)
First, resin foam particles were produced using the production apparatus shown in FIGS.
That is, 100 parts by mass of 1,4-cyclohexanedimethanol-modified polyethylene terephthalate resin (manufactured by Eastman Co., Ltd., trade name “EN099”, melting point: 238.5 ° C.), master batch (polyethylene) containing polyethylene terephthalate resin and talc. (Terephthalate resin content: 60% by mass, talc content: 40% by mass) 1,4-cyclohexanedimethanol modified polyethylene terephthalate resin composition containing 1.8 parts by mass and pyromellitic anhydride 0.26 parts by mass The mixture was supplied to a single screw extruder having a length of 65 mm and an L / D ratio of 35, and melt kneaded at 290 ° C.

  Subsequently, mixed butane composed of 35% by mass of isobutane and 65% by mass of normal butane was added from the middle of the extruder to 1.6 parts by mass with respect to 100 parts by mass of the total amount of 1,4-cyclohexanedimethanol-modified polyethylene terephthalate resin and polyethylene terephthalate resin. A mixture of 1,4-cyclohexanedimethanol-modified polyethylene terephthalate resin and polyethylene terephthalate resin (hereinafter simply referred to as “modified”) is pressed into the molten 1,4-cyclohexanedimethanol-modified polyethylene terephthalate resin composition so as to be part by mass. In polyethylene terephthalate resin)).

  Thereafter, the modified polyethylene terephthalate resin composition in a molten state is cooled to 280 ° C. at the front end of the extruder, and then the modified polyethylene terephthalate resin composition is discharged from each nozzle of the multi-nozzle mold 1 attached to the front end of the extruder. Extrusion foamed.

  The multi-nozzle mold 1 has 20 nozzles having an outlet portion 11 having a diameter of 1 mm, and the outlet portions 11 of the nozzle all have a diameter of 139.5 mm assumed on the front end face 10 of the multi-nozzle die 1. What was arrange | positioned on the virtual circle A at equal intervals was used.

  As the device, two rotary blades 5 are integrally provided on the outer peripheral surface of the rear end portion of the rotary shaft 2 with a phase difference of 180 ° in the circumferential direction of the rotary shaft 2. However, what was comprised so that it might move on the virtual circle A in the state which always contacted the front-end surface 10 of the multi-nozzle metal mold | die 1 was used.

Further, as the device, the cooling member 4 includes a front circular front part 41a and a cylindrical peripheral wall part 41b extending rearward from the outer peripheral edge of the front part 41a and having an inner diameter of 320 mm. What provided the cooling drum 41 was used.
And the cooling water 42 of 20 degreeC was supplied in the cooling drum 41 through the supply pipe | tube 41d and the supply port 41c of the cooling drum 41, and the said resin foam particle was produced.
The volume in the cooling drum 41 was 17684 cm ³ .

  The cooling water 42 is spirally drawn along the inner peripheral surface of the peripheral wall portion 41b of the cooling drum 41 by the centrifugal force accompanying the flow velocity when the supply pipe 41d is supplied to the inner peripheral surface of the peripheral wall portion 41b of the cooling drum 41. The cooling water 42 is advanced forward and gradually spreads in a direction perpendicular to the traveling direction while traveling along the inner peripheral surface of the peripheral wall portion 41b. As a result, the cooling water 42 is further forward than the supply port 41c of the cooling drum 41. The inner peripheral surface of the peripheral wall portion 41 b was completely covered with the cooling water 42.

Then, the modified polyethylene terephthalate extrudate extruded and foamed from the outlet portion 11 of each nozzle of the multi-nozzle mold 1 by rotating the rotary blade 5 disposed on the front end face 10 of the multi-nozzle mold 1 at a rotational speed of 2500 rpm. Was cut with a rotary blade 5 to produce substantially spherical modified polyethylene terephthalate resin expanded particles.
At this time, the modified polyethylene terephthalate extrudate consisted of an unfoamed portion that maintained the state immediately after being extruded from the nozzle of the multi-nozzle mold 1 and a foamed portion that was in the process of foaming and continued to the unfoamed portion. .
The modified polyethylene terephthalate extrudate was cut at the open end of the outlet 11 of the nozzle, and the modified polyethylene terephthalate extrudate was cut at the unfoamed portion.

In the production of the above modified polyethylene terephthalate foamed particles for in-mold foam molding, first, the rotating shaft 2 was not attached to the multi-nozzle mold 1 and the cooling member 4 was retracted from the multi-nozzle mold 1.
In this state, the modified polyethylene terephthalate extrudate is extruded and foamed from an extruder, and the modified polyethylene terephthalate extrudate is expanded immediately after being extruded from the nozzle of the multi-nozzle mold 1 and foamed continuously to the unfoamed portion. It was confirmed that it consisted of a foamed part on the way.
Next, after attaching the rotating shaft 2 to the multi-nozzle mold 1 and disposing the cooling member 4 at a predetermined position, the rotating shaft 2 is rotated to rotate the modified polyethylene terephthalate extrudate at the opening end of the outlet portion 11 of the nozzle. Modified polyethylene terephthalate foamed particles were produced by cutting with a blade 5.

  The modified polyethylene terephthalate expanded particles fly the extrudate outward or forward by the cutting stress of the rotary blade 5, and the cooling water 42 flowing along the inner surface of the cooling drum 41 of the cooling member 4 The cooling water 42 was caused to collide with the surface of the cooling water 42 in an oblique direction so as to follow the cooling water 42 from the upstream side to the downstream side, and entered the cooling water 42 to be immediately cooled. .

  The cooled modified polyethylene terephthalate expanded particles were discharged together with the cooling water 42 through the discharge port 41e of the cooling drum 41, and then separated from the cooling water 42 by a dehydrator.

The modified polyethylene terephthalate expanded particles had a bulk density of 0.14 g / cm ³ .

An in-mold foam molding machine equipped with molds (male mold and female mold) was prepared.
In a state where the male mold and the female mold are clamped, a rectangular parallelepiped cavity having an internal dimension of 300 mm in length, 400 mm in width, and 50 mm in height is formed between the male and male molds.

Modified polyethylene terephthalate foam particles were filled in the mold cavity of the in-mold foam molding machine, and the mold was clamped.
Thereafter, water vapor is introduced into the cavity from one mold and passed through the other mold, and in the heating step, the modified polyethylene terephthalate foamed particles are heated with water vapor of 0.03 MPa gauge pressure for 30 seconds. Next, in the double-sided heating process in which water vapor is introduced from both molds into the cavity and the water vapor supplied into the cavity is not discharged, the modified polyethylene terephthalate foamed particles are treated with water vapor at a gauge pressure of 0.03 MPa for 30 seconds. The foamed particles obtained by secondarily foaming the modified polyethylene terephthalate foam particles by heating and secondarily foaming the modified polyethylene terephthalate foam particles are thermally fused to each other by these foaming pressures. After that, a 3-second heat retention process is performed in which only the supply of water vapor is stopped and the mold is allowed to cool to the atmosphere. Te to obtain a foam having a rectangular parallelepiped shape of vertical 300 mm × horizontal 400 mm × thickness 50 mm.

Reinforcing fiber resin material (made by BOND LAMINATES, trade name "TEPEX dynamic 108", synthetic resin for reinforcement: thermoplastic polyurethane (TPU), basis weight: 400 g / m ² , thickness: 0.5 mm ) Were prepared.
The fiber reinforced resin material contained 45% by mass of TPU resin as a thermoplastic resin.
The reinforcing fiber base constituting the fiber reinforced resin material is preliminarily overlapped so that the length direction of the warp is 0 ° and 90 ° in order to have a thickness of 0.5 mm.

Two of the prepared fiber reinforced resin materials were heated with an infrared heater at 280 ° C. for 10 seconds.
With the two fiber reinforced resin materials in the heated state, a resin foam is sandwiched from above and below in the thickness direction, and a pre-laminated body in the order of lamination of fiber reinforced resin layer / core material / fiber reinforced resin layer is produced in order from the bottom. .
In addition, by laminating the heated fiber reinforced resin material on the resin foam, only the surface of the resin foam is heated by heat conduction.

Next, the mold of the press machine in which the mold temperature of 100 ° C. is set so that the temperature “Tc (° C.)” of the center of the resin foam is equal to or higher than “T ₂₀ (° C.)” (Tc ≧ T ₂₀ ). A pre-laminated body was placed on the pre-laminated body, and the pre-laminated body was pressed with a pressure of 0.6 MPa.
Since the resin foam with the main surface of the laminated surface of the fiber reinforced resin material is softened by heat conduction from the fiber reinforced resin material, it is foamed so that the foam density is 0.25 g / cm ^3. The body surface was compressed for 1 minute and cooled until the mold temperature became 60 ° C. below the glass transition point of the resin foam, and the thermoplastic fiber reinforced composite was taken out.

(Density variation)
Test specimens were collected from arbitrary 10 locations in the resin foam in the fiber reinforced composite.
The mass of the collected specimen was measured, and then the specimen was placed in a graduated cylinder filled with water, and the volume was measured.
Then, the arithmetic mean value of the density of each test piece was defined as “average core material density”, and the density variation was evaluated based on the number of test pieces whose density was 20% or more different from the “average core material density”.

○: Less than two.
Δ: Two or more and less than five.
X: 6% or more.

(Lightening effect)
Since the obtained thermoplastic fiber reinforced composite compressed the foam by molding, the weight reduction effect of the thermoplastic fiber reinforced composite was evaluated based on the following criteria.
Weight reduction effect (%) = 100 × (foam thickness after molding of plastic fiber reinforced composite / foam thickness)

○: 80% or more.
Δ: 60% or more and less than 80%.
X: Less than 60%.

(Surface appearance)
In the fiber reinforced composite, the total surface area (S0) of the fiber reinforced resin layer and the total area (S1) of the portion where the reinforced fibers are exposed on the surface are calculated. The degree of exposure was calculated.
Judgment was made according to the following criteria based on the degree of exposure of the fibers.
In addition, it was set as "x" when the fiber reinforced composite was not obtained.

Fiber exposure (%) = 100 × S1 / S0

○: The degree of fiber exposure was less than 10%.
Δ: Fiber exposure was 10% or more and less than 20%.
X: Fiber exposure was 20% or more.

(Examples 2, 3, 5-8, 10, Comparative Examples 1-4)
About the other Example and the comparative example, it implemented like the table | surface similarly to Example 1. FIG.
In Examples 5 and 9, the resin foam was produced as follows.

(Examples 4 and 9)
Instead of the modified polyethylene terephthalate resin composition, a styrene-methyl methacrylate-maleic anhydride copolymer (styrene unit: 45.9% by mass, methyl methacrylate unit: 21.5% by mass, maleic anhydride unit: 32.%). 6% by mass, manufactured by Denki Kagaku Kogyo Co., Ltd., trade name “Regisphi R200”, 100 parts by mass of glass transition temperature Tg: 140.7 ° C., styrene-methyl methacrylate-maleic anhydride copolymer (styrene unit: 45.9) Mass%, methyl methacrylate unit: 21.5 mass%, maleic anhydride unit: 32.6 mass%, manufactured by Denki Kagaku Kogyo Co., Ltd., trade name “Regisphi R200”, glass transition temperature Tg: 140.7 ° C.) Master batch (styrene-methyl methacrylate-maleic anhydride copolymer content: 60% by mass, (Luc content: 40% by mass) A styrene-methyl methacrylate-maleic anhydride copolymer resin composition containing 1.8 parts by mass and pyromellitic anhydride 0.26 parts by mass is supplied to a single screw extruder and foamed. Particles were produced to produce a resin foam.
Otherwise, fiber reinforced composites were produced as shown in the table.
In the table, the styrene-methyl methacrylate-maleic anhydride copolymer is expressed as “acryl”.

The results are shown in Table 1.

  Also from this, according to the present invention, it is possible to provide a production method capable of easily producing a fiber-reinforced composite having excellent dimensional accuracy and a resin foam for forming a composite useful for such a production method. Recognize.

6: Resin foam 7: Fiber reinforced resin material B: Mold C: Release film D: Breather cloth E: Bagging film F: Sealing material G: Back valve H: Space M: Laminate P1, P2: Hot plate

Claims (7)

A fiber reinforced resin material and a resin foam are used to form a fiber reinforced composite obtained by laminating and integrating, and the resin foam and the fiber reinforced resin material contain a thermoplastic resin, and the resin foam and the A resin foam for forming a composite used for forming a fiber reinforced composite in which a fiber reinforced resin material is laminated and integrated by heat fusion,
A blowing agent containing less 5.0 wt% 0.1 wt%, complexation inflation pressure at a temperature of dimensional change upon heating becomes + 20% or less 0.1 mN / mm ³ or more 20 mN / mm ³ Resin foam.   The composite foam-forming resin foam according to claim 1, which is a resin foam obtained by heat-sealing a plurality of foamed thermoplastic resin particles.   The resin foam for forming a composite according to claim 1 or 2, which exhibits an increase in volume at a rate of 5 vol% / min or more when heated.   The resin foam for forming a composite according to any one of claims 1 to 3, comprising an acrylic resin or a polyester resin as a main resin. A laminating step is performed in which a resin foam containing a thermoplastic resin and a fiber reinforced resin material containing a thermoplastic resin are laminated and integrated by thermal fusion to form a fiber reinforced composite,
In the lamination integration of the resin foam and the fiber reinforced resin material in the lamination step, a mold corresponding to the product shape of the fiber reinforced composite to be produced is used.
In the laminating step, a fiber-reinforced composite manufacturing method for producing a fiber-reinforced composite shaped by the mold,
The manufacturing method of the fiber reinforced composite_body | complex using the resin foam for composite formation of any one of Claims 1 thru | or 4 as the said resin foam. In the lamination step,
Laminating the fiber reinforced resin material in a heated state on the resin foam to produce a pre-laminated body,
Pressure is applied to the preliminary laminate by the mold, and the fiber-reinforced resin material and the resin foam are thermally fused under pressure conditions,
When the temperature at which the heating dimensional change rate of the resin foam is + 5% is T ₅ (° C.), and the temperature at which the heating dimensional change rate of the resin foam is + 20% is T ₂₀ (° C.),
The preliminary laminate is prepared by adjusting the temperature of the resin foam so that at least the central part of the resin foam is at least 10 (° C.) lower than T ₅ (° C.),
In the heat sealing, the temperature of the resin foam is adjusted so that the center of the resin foam has a temperature equal to or higher than T ₂₀ (° C.), and the expansion pressure of the resin foam is adjusted with the fiber reinforced resin material. The method for producing a fiber-reinforced composite according to claim 5, which is used for heat fusion with a resin foam.   The method for producing a fiber-reinforced composite according to claim 5 or 6, wherein the fiber-reinforced composite to be manufactured is any one of a movable body constituting member, an electronic device casing, and a wind turbine blade.

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