JP2019183093A - Foam particle, foam molded body, fiber reinforced composite and automobile component - Google Patents

Abstract

An object of the present invention is to provide a foamed molded article having excellent mechanical properties and foamed particles from which the foamed molded article can be produced. The foamed particles are composed of a base resin containing a copolymer of an aromatic vinyl, a (meth) acrylic acid ester, and an unsaturated dicarboxylic acid. In a cross-sectional photograph taken of an area of 9 mm 2, the above-mentioned problems are solved by foamed particles characterized by comprising small bubbles having a bubble diameter of 50 μm or more and less than 300 μm and large bubbles having a bubble diameter of 300 μm or more and 2 mm or less. . [Selection diagram] Fig. 1

Description

  The present invention relates to expanded particles, expanded molded articles, fiber reinforced composites, and automotive parts. More specifically, the present invention relates to foamed particles that can provide a foamed molded article having improved mechanical properties, and a foamed molded article, a fiber reinforced composite, and an automotive part obtained from the foamed particle.

In recent years, vehicles such as aircraft, automobiles, and ships have been required to improve fuel efficiency in order to reduce the burden on the global environment, and the metal materials that make up these vehicles have been changed to resin materials to achieve significant weight savings. The flow is getting stronger. Examples of these resin materials include fiber reinforced plastics, and it has been studied to further reduce weight and increase rigidity by using a lightweight core material in part. Polystyrene foam having high compressive strength has been studied as a material used as a lightweight core material.
However, since the polystyrene-based resin has a low glass transition temperature, mechanical properties such as heat resistance are not sufficient. Therefore, it has been desired to provide a foamed molded article having improved mechanical properties and foamed particles capable of producing the foamed molded article.
Therefore, the applicant of the present application repeated the test under the idea that mechanical properties would be improved if another type of resin was used instead of the polystyrene resin. As a result, when using a copolymer of aromatic vinyl, (meth) acrylic acid ester, and unsaturated dicarboxylic acid as a base resin for the foamed particles, the mechanical properties of the foamed molded product can be improved to some extent, It has been found that the mechanical properties can be greatly improved by controlling the bubble diameter constituting the expanded particles while using this base resin (Japanese Patent Laid-Open No. 2017-186503: Patent Document 1).

JP 2017-186503 A

However, it is desired to provide a foamed molded product having mechanical properties further superior to the foamed molded product of Patent Document 1 and foamed particles capable of producing the foamed molded product.
Then, this invention makes it a subject to provide the foaming particle | grains which can manufacture the foaming molding which shows the outstanding mechanical property, and the foaming molding.

  The inventor of the present invention further studied the technique of Patent Document 1, and surprisingly found that the mechanical properties can be greatly improved by increasing the difference in the bubble diameter between the small bubbles and the large bubbles. The invention has been completed.

Thus, according to the present invention, there are expanded particles composed of a base resin containing a copolymer of aromatic vinyl, (meth) acrylic acid ester and unsaturated dicarboxylic acid, and the expanded particles are 30 times larger. in in cross-section photograph of an area of 11.9 mm ^2, the foamed particles are provided, characterized in that it comprises a large air bubbles below bubble size small bubbles and 300μm or more and 2mm of bubble size less than 50μm or more and 300μm The
Further, according to the present invention, there is provided a foam molded article composed of a base resin containing a copolymer of aromatic vinyl, (meth) acrylic acid ester and unsaturated dicarboxylic acid, wherein the foam molded article is is composed of a plurality of the foamed particles, the foamed particles in a cross section photograph of an area of 11.9 mm ² at 30 times, the cell diameter of less than 50μm or more and 300μm small bubbles and 300μm or more and 2mm or less of the bubble There is provided a foamed molded product comprising large diameter bubbles.
Furthermore, according to the present invention, there is provided a fiber reinforced composite comprising the above foam molded body and a fiber reinforced plastic layer laminated and integrated on the surface of the foam molded body.
Moreover, according to this invention, the components for motor vehicles comprised from said foaming molding or a fiber reinforced composite are provided.

ADVANTAGE OF THE INVENTION According to this invention, the foaming particle which can manufacture the foaming molding which shows the outstanding mechanical property, and the foaming molding can be provided.
Moreover, in any of the following cases, a foamed molded article exhibiting more excellent mechanical properties and foamed particles capable of producing the foamed molded article can be provided.
(1) The expanded particles have only one large bubble in one of them.
(2) Aromatic vinyl is a styrenic monomer, (meth) acrylic acid ester is (meth) acrylic acid alkyl ester (the alkyl group has 1 to 5 carbon atoms), and unsaturated dicarboxylic acid is 2 to 6 carbon atoms. An aliphatic unsaturated dicarboxylic acid, and the copolymer is aromatic when the total of units derived from three of vinyl aromatic, (meth) acrylic acid ester and unsaturated dicarboxylic acid is 100 parts by weight. 30 to 80 parts by weight of units derived from vinyl, 8 to 35 parts by weight of units derived from (meth) acrylic acid ester, and 10 to 50 parts by weight of units derived from unsaturated dicarboxylic acid.

It is a cross-sectional photograph of the expanded particle of Example 1-3, and a foaming molding. It is a cross-sectional photograph of the expanded particles and expanded molded articles of Comparative Examples 1 and 2. It is a cross-sectional photograph of the expanded particle of Example 4 and 5, and a foaming molding. It is a cross-sectional photograph of the expanded particle of Examples 6-8 and a foaming molding.

(1) Foamed particles (1-1) Base resin The foamed particles are composed of a base resin containing a copolymer of aromatic vinyl, (meth) acrylic acid ester, and unsaturated dicarboxylic acid. The proportion of the copolymer in the base resin is preferably 70% by weight or more, more preferably 85% by weight or more, and may be 100% by weight. The copolymer preferably has a glass transition temperature Tg of 115 to 160 ° C. When Tg is lower than 115 ° C., lamination and integration of the skin material on the surface of the foamed molded product produced using the foamed particles may be insufficient, and mechanical properties may be lowered. When the temperature is higher than 160 ° C., the foamability of the foamed particles is lowered, and the heat fusion integration between the foamed particles is insufficient, and the mechanical properties of the foamed molded product may be lowered. A more preferable Tg is 120 to 150 ° C.

(A) Aromatic vinyl Aromatic vinyl is an aromatic compound having a substituent composed of a vinyl group. The number of vinyl groups and the number of carbon atoms of the aromatic compound are not particularly limited. Specific aromatic vinyls include styrene monofunctional monomers such as styrene, α-methyl styrene, vinyl toluene, ethyl styrene, i-propyl styrene, t-butyl styrene, dimethyl styrene, bromostyrene, chlorostyrene, Divinylbenzene, trivinylbenzene, divinyltoluene, divinylxylene, bis (vinylphenyl) methane, bis (vinylphenyl) ethane, bis (vinylphenyl) propane, bis (vinylphenyl) butane, divinylnaphthalene, divinylanthracene, divinylbiphenyl, Examples thereof include bisphenol A ethylene oxide adduct di (meth) acrylate and bisphenol A propylene oxide adduct di (meth) acrylate. Aromatic vinyl may be used independently or 2 or more types may be used together. Of these, styrene is preferred from the viewpoint of availability.
(B) (Meth) acrylic acid ester The (meth) acrylic acid ester is not particularly limited, and examples thereof include (meth) acrylic acid alkyl esters. The carbon number of the alkyl group in the (meth) acrylic acid alkyl ester can be 1 to 5. Specific examples of (meth) acrylic acid esters include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and butyl (meth) acrylate. (Meth) acrylic acid ester may be used independently, or 2 or more types may be used together. From the viewpoint of improving the mechanical properties of the foam molded article, methyl (meth) acrylate is preferred, and methyl methacrylate is more preferred.
(C) Unsaturated dicarboxylic acid Although unsaturated dicarboxylic acid is not specifically limited, C2-C6 aliphatic unsaturated dicarboxylic acid is mentioned. Specific examples of the unsaturated dicarboxylic acid include maleic acid, itaconic acid, citraconic acid, aconitic acid, and anhydrides thereof. Unsaturated dicarboxylic acid may be used independently or 2 or more types may be used together.

(D) Ratio of units derived from aromatic vinyl, (meth) acrylic acid ester and unsaturated dicarboxylic acid The total number of units derived from aromatic vinyl, (meth) acrylic acid ester and unsaturated dicarboxylic acid is 100. Assuming parts by weight, 30 to 80 parts by weight of units derived from aromatic vinyl, 8 to 35 parts by weight of units derived from (meth) acrylic acid ester, and 10 to 50 parts by weight of units derived from unsaturated dicarboxylic acid It is preferable to contain.
When the proportion of units derived from aromatic vinyl is less than 30 parts by weight, the foamability of the foamed particles is reduced during foam molding, and the heat fusion integration between the foamed particles becomes insufficient, and Mechanical properties may deteriorate. When this ratio is larger than 80 parts by weight, the heat resistance of the foamed molded product may be lowered. This ratio is more preferably 40 to 75 parts by weight, and still more preferably 45 to 70 parts by weight.
When the proportion of units derived from (meth) acrylic acid ester is less than 8 parts by weight, the mechanical properties of the foamed molded product may be lowered. When this ratio is larger than 35 parts by weight, the foamability of the foamed particles may be reduced during foam molding, and the heat fusion integration between the foamed particles may be insufficient and the mechanical properties of the foamed molded product may be degraded. is there. This ratio is more preferably 10 to 33 parts by weight, and still more preferably 15 to 30 parts by weight.
When the ratio which the unit derived from unsaturated dicarboxylic acid accounts is less than 10 weight part, the heat resistance of a foaming molding may fall. When this ratio is larger than 50 parts by weight, the foamability of the foamed particles may be reduced during foam molding, and the heat-fusion integration between the foamed particles may be insufficient, and the mechanical properties of the foamed molded product may be degraded. is there. This ratio is more preferably 15 to 40 parts by weight, and still more preferably 20 to 35 parts by weight.
In addition, the usage-amount of a monomer and content of the unit derived from the monomer are substantially in agreement.
Each component ratio, that is, the proportion of units derived from aromatic vinyl, (meth) acrylic acid ester and unsaturated dicarboxylic acid, and further the units derived from other monomers and other resins described below is ¹ It can be defined by the peak height of H-NMR or the area ratio of FT-IR. A specific measurement method will be described in Examples.

(E) Other monomer The base resin may be a further copolymer with components derived from other monomers as long as the properties of the present invention are not impaired in addition to the above three monomers. Examples of other monomers include (meth) acrylonitrile, dimethyl maleate, diethyl maleate, dimethyl fumarate, diethyl fumarate, ethyl fumarate, (meth) acrylic acid, and the like.
The proportion of units derived from other monomers in the base resin is preferably 30% by weight or less, and may be 0% by weight.
(F) Other resin Other resin may be mixed with the base resin. Other resins include polyolefin-based resins such as polyethylene and polypropylene, rubber-modified resistances added with diene rubber-like polymers such as polybutadiene, styrene-butadiene copolymers, and ethylene-propylene-nonconjugated diene three-dimensional copolymers. Impact polystyrene resin, polycarbonate resin, polyester resin, polyamide resin, polyphenylene ether, acrylonitrile-butadiene-styrene copolymer, acrylonitrile-styrene copolymer, polymethyl methacrylate, styrene- (meth) acrylic acid copolymer Styrene- (meth) acrylic acid ester copolymer, aromatic vinyl-unsaturated dicarboxylic acid-unsaturated dicarboxylic imide copolymer, and the like.
Of the other resins, the expanded particles preferably contain polymethyl methacrylate. By containing poly (methyl methacrylate), the heat-fusibility of the foamed particles is improved, and the foamed particles are more strongly heat-fused and integrated with each other. Obtainable. The content of polymethyl methacrylate in the expanded particles is preferably 10 to 500 parts by weight, more preferably 20 to 450 parts by weight, and particularly preferably 30 to 400 parts by weight with respect to 100 parts by weight of the copolymer.

The foamed particles preferably contain an acrylic resin as a processing aid. By containing a processing aid, the foam tension of the foamed particles is suppressed by making the melt tension (viscoelasticity) at the time of foaming of the resin constituting the foamed particles suitable for foaming. Thus, it is possible to produce a foamed molded article having improved mechanical properties by further strengthening heat fusion between the foamed particles. The content of the processing aid in the expanded particles is preferably 0.5 to 5 parts by weight, more preferably 0.5 to 3 parts by weight with respect to 100 parts by weight of the copolymer.
The acrylic resin as a processing aid is not particularly limited, and contains 50% by weight or more of a homopolymer of an acrylic monomer or a copolymer composed of two or more of these, and an acrylic monomer. Examples thereof include a copolymer of an acrylic monomer and a vinyl monomer copolymerizable therewith. Examples of the acrylic monomer include methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate and the like. Examples of the vinyl monomer copolymerizable with the acrylic monomer include α-methylstyrene and acrylonitrile. The weight average molecular weight of the acrylic resin is preferably 1.5 million to 6 million, more preferably 2 million to 4.5 million, and particularly preferably 2.5 million to 4 million. Even if the weight average molecular weight of the acrylic resin is too low or too high, it is difficult to sufficiently adjust the melt tension (viscoelasticity) during foam molding of the resin constituting the foamed particles to that suitable for foaming. The foamability of the particles may not be improved.

(G) Aromatic vinyl-unsaturated dicarboxylic acid-unsaturated dicarboxylic imide copolymer As the above (f) other resin, an aromatic vinyl-unsaturated dicarboxylic acid-unsaturated dicarboxylic imide copolymer is used. It is preferable from the viewpoint of improving the heat resistance of the foam molded article.
Although it does not specifically limit as aromatic vinyl, The compound illustrated to said (a) is mentioned. Aromatic vinyl may be used independently or 2 or more types may be used together. Of these, styrene is preferred from the viewpoint of availability.
Although it does not specifically limit as unsaturated dicarboxylic acid, The compound illustrated in said (c) is mentioned. Unsaturated dicarboxylic acid may be used independently or 2 or more types may be used together. From the viewpoint of improving the mechanical properties of the foam molded article, maleic anhydride is preferable.
The unsaturated dicarboxylic acid imide is not particularly limited, and examples thereof include maleimide monomers such as maleimide, N-methylmaleimide, N-ethylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, and N-naphthylmaleimide. . An unsaturated dicarboxylic imide derivative may be used independently or 2 or more types may be used together. From the viewpoint of improving the heat resistance of the foam molded article, N-phenylmaleimide is preferred.
The proportion of units derived from aromatic vinyl, unsaturated dicarboxylic acid and unsaturated dicarboxylic imide is 20 to 80 parts by weight of units derived from aromatic vinyl, assuming that the total of the units derived from 3 is 100 parts by weight. It is preferable that 2 to 30 parts by weight of units derived from unsaturated dicarboxylic acid and 20 to 80 parts by weight of units derived from unsaturated dicarboxylic imide are included.
When the proportion of units derived from aromatic vinyl is less than 20 parts by weight, the foamability of the foamed particles is reduced during foam molding, and the thermal fusion integration between the foamed particles becomes insufficient, and Mechanical properties may deteriorate. When this ratio is larger than 80 parts by weight, the heat resistance of the foamed molded product may be lowered. This ratio is more preferably 30 to 75 parts by weight, and still more preferably 50 to 70 parts by weight.
(H) Additive The base resin may contain an additive in addition to the resin, if necessary. Additives include plasticizers, flame retardants, flame retardant aids, antistatic agents, spreading agents, foam control agents, fillers, colorants, weathering agents, anti-aging agents, lubricants, antifogging agents, fragrances, etc. Can be mentioned.

(1-2) Configuration The expanded particle has a bubble size of 50 μm or more and less than 300 μm and a bubble size of 300 μm or more and 2 mm or less in a cross-sectional photograph of the whole expanded particle obtained by photographing an area of 11.9 mm ² at 30 times. With large bubbles.
Further, the number of large bubbles per one expanded particle is not particularly limited and may be plural. However, if the number is too large, the bubble rate is increased, and the mechanical properties of the foamed molded product are lowered. For this reason, it is preferable that the expanded particle has only one large bubble in one of them, although it depends on the bubble diameter of the large bubble.
Moreover, it is preferable that there is a difference of 300 μm or more between the average bubble diameter of small bubbles and the average bubble diameter of large bubbles. Due to this difference, it is possible to provide foamed particles that give a foamed molded article having improved mechanical properties. A more preferable difference is 300 to 600 μm. Here, the average bubble diameter of small bubbles is preferably in the range of 100 to 250 μm, and the average bubble diameter of large bubbles is preferably in the range of 350 to 900 μm.

The outer shape of the expanded particles is not particularly limited as long as the expanded molded body can be produced, and examples thereof include a spherical shape, a substantially spherical shape, and a cylindrical shape. The expanded particles preferably have an outer shape represented by an average aspect ratio of 0.7 or more (the upper limit is 1 true sphere).
The expanded particles preferably have a bulk multiple of 30 to 2 times. When the bulk factor is larger than 30 times, the open cell ratio of the foamed particles increases, and the foamability of the foamed particles may decrease during foam molding. If it is less than 2 times, the foamed particles may have uneven bubbles, and the foamability of the foamed particles during foam molding may be insufficient. The bulk multiple is more preferably 25 to 3 times, and particularly preferably 20 to 5 times.

(1-3) Manufacturing method As a manufacturing method of foamed particle, the method of making a foaming particle the resin particle by impregnating a foaming agent with a foaming agent, and foaming a foamable particle is mentioned.
The resin particles can be obtained using a known production method and production equipment. Here, the adjustment of the number of voids described below can be performed, for example, by adjusting the amount of chemical foaming agent added to the resin.
For example, resin particles can be produced by melt-kneading the raw material resin using an extruder and then granulating by extrusion, underwater cut (underwater cut), strand cut, or the like. The temperature, time, pressure, etc. at the time of melt-kneading can be appropriately set according to the raw materials used and the production equipment.
The melt kneading temperature in the extruder at the time of melt kneading is preferably 220 to 280 ° C, more preferably 240 to 270 ° C, which is a temperature at which the raw material resin is sufficiently softened. The melt-kneading temperature means the temperature of the melt-kneaded material inside the extruder as measured at the center temperature of the melt-kneaded material flow path near the extruder head with a thermocouple thermometer.
The large bubbles, which are one of the characteristics of the expanded particles of the present invention, are considered to be derived from voids formed in the central region of the resin particles by rapid cooling from the surroundings during the production of the resin particles. Therefore, in the production of foamed particles, an underwater cut that is easily controlled for rapid cooling is particularly preferable.
In addition, it is preferable that a bubble regulator is supplied to an extruder. Examples of the air conditioner include polytetrafluoroethylene powder, polytetrafluoroethylene powder modified with an acrylic resin, and talc. As for the quantity of a bubble regulator, 0.01-5 weight part is preferable with respect to 100 weight part of resin compositions. When the amount of the bubble adjusting agent is less than 0.01 weight, the bubbles of the foamed particles become coarse and the appearance of the obtained foamed molded product may be deteriorated. When the amount is more than 5 parts by weight, the closed cell ratio of the foamed particles may decrease due to bubble breakage. The amount of the bubble regulator is more preferably 0.05 to 3 parts by weight, particularly preferably 0.1 to 2 parts by weight.

Next, as a method for producing expandable particles, a method in which a foaming agent is impregnated in a gas phase with a foaming agent in a hermetically sealed container can be mentioned. Examples of the blowing agent include propane, normal butane, isobutane, normal pentane, isopentane, hexane and other saturated aliphatic hydrocarbons, ethers such as dimethyl ether, methyl chloride, 1,1,1,2-tetrafluoroethane, 1, Examples thereof include chlorofluorocarbons such as 1-difluoroethane and monochlorodifluoromethane, and inorganic gases such as carbon dioxide and nitrogen. Among them, dimethyl ether, propane, normal butane, isobutane, and carbon dioxide are preferable, propane, normal butane, isobutane, and carbon dioxide are more preferable, and normal butane, isobutane, and carbon dioxide are particularly preferable. In addition, a foaming agent may be used independently or 2 or more types may be used together.
If the amount of the foaming agent charged into the container is too small, the foamed particles may not be foamed to a desired expansion ratio. If the amount of the foaming agent is too large, the foaming agent acts as a plasticizer, so that the viscoelasticity of the base resin is excessively lowered, the foamability is lowered, and good foamed particles may not be obtained. Therefore, the amount of the foaming agent is preferably 0.1 to 5 parts by weight, more preferably 0.2 to 4 parts by weight, and particularly preferably 0.3 to 3 parts by weight with respect to 100 parts by weight of the raw material resin.
Furthermore, as a manufacturing method of expanded particle, the method of heating with a heating medium like water vapor | steam in the container which can be sealed is mentioned. Examples of the heating conditions include a gauge pressure of 0.3 to 0.5 MPa, a temperature of 120 to 159 ° C., and 10 to 180 seconds.
The particle diameter of the expanded particles can be changed by changing the diameter of a multi-nozzle mold attached to the front end of the extruder.

(2) Foam molded body (2-1) Base resin The base resin constituting the foam molded body is the same as the base resin of the foamed particles.
(2-2) Physical properties The foamed molded article is a cross-sectional photograph obtained by photographing an area of 11.9 mm ² at 30 times. A small bubble having a bubble diameter of 50 μm or more and less than 300 μm and a large bubble having a bubble diameter of 300 μm or more and 2 mm or less And.
Further, the number of large bubbles per one expanded particle is not particularly limited and may be plural. However, if the number is too large, the bubble rate is increased, and the mechanical properties of the foamed molded product are lowered. For this reason, it is preferable that the expanded particle has only one large bubble in one of them, although it depends on the bubble diameter of the large bubble.
Moreover, it is preferable that there is a difference of 300 μm or more between the average bubble diameter of small bubbles and the average bubble diameter of large bubbles. Due to this difference, it is possible to provide foamed particles that give a foamed molded article having improved mechanical properties. A more preferable difference is 300 to 600 μm. Here, the average bubble diameter of small bubbles is preferably in the range of 100 to 250 μm, and the average bubble diameter of large bubbles is preferably in the range of 350 to 900 μm.

The outer shape of the fused expanded particles is not particularly limited as long as the expanded molded body can be maintained.
The foamed molded article preferably has a multiple of 30 to 2 times. When the multiple is larger than 30 times, the mechanical properties may be insufficient. If it is less than 2 times, the advantage of foaming may be reduced due to increased weight. The multiple is more preferably 27 to 3 times, and particularly preferably 25 to 5 times.
Thus, the foamed molded article preferably has a density of ^{0.046~0.23g / cm 3 (46~230kg / cm} 3).

The bending maximum point stress per unit density in the foam molded article is preferably 0.012 MPa / (kg / m ³ ) or more. If the bending maximum point stress is too small, the foamed molded product may be easily broken.
The flexural modulus per unit density in the foamed molded product is preferably 0.4 MPa / (kg / m ³ ) or more. If the flexural modulus is too small, the foamed molded product may be deformed by pressure applied when a skin material such as fiber reinforced plastic is laminated and integrated on the surface of the foamed molded product.
5% compressive stress per unit density in the foam molded article is preferably from 0.007MPa / (kg / m ³⁾ or ^{more, 0.009MPa / (kg / m 3} ) or more is more preferable. If the 5% compression is too small, the foam molded body may be deformed by the pressure applied when a skin material such as fiber reinforced plastic is laminated and integrated on the surface of the foam molded body.
The compression elastic modulus per unit density in the foam molded article is preferably 0.3 MPa / (kg / m ³ ) or more. If the compression elastic modulus is too small, the foam molded body may be deformed by the pressure applied when a skin material such as fiber reinforced plastic is laminated and integrated on the surface of the foam molded body.

(2-3) Manufacturing method As a manufacturing method of a foaming molding, the foaming particle is filled in the cavity of a metal mold | die, a heating medium is supplied in a cavity, a foaming particle is heated and re-foamed, and re-foaming is carried out. A method of obtaining a foamed molded article by heat-bonding and integrating the foamed particles to each other by these foaming pressures. Examples of the heating medium include water vapor, hot air, hot water and the like, and water vapor is preferable.

(2-4) Applications The foamed molded article is excellent in light weight, heat resistance and mechanical properties, and particularly excellent in load resistance in a high temperature environment. Therefore, for example, it can be suitably used for parts of transportation equipment such as automobiles, airplanes, railway vehicles, and ships. Examples of automobile parts include parts used in the vicinity of the engine and exterior materials.
According to the present invention, there is provided an automotive part composed of the foamed molded article of the present invention. Examples of the automotive part include a floor panel, a roof, a bonnet, a fender, an under cover, a wheel, a steering wheel, and a container. (Housing), hood panel, suspension arm, bumper, sun visor, trunk lid, luggage box, seat, door, cowl and other parts.

A skin material may be laminated and integrated on the surface of the foamed molded product to be used as a reinforced composite. When the foamed molded body is a foamed sheet, it is not necessary to be laminated and integrated on both surfaces of the foamed molded body, and the skin material only needs to be laminated and integrated on at least one surface of both surfaces of the foamed molded body. The lamination of the skin material may be determined according to the use of the reinforced composite. Among these, in consideration of the surface hardness and mechanical strength of the reinforced composite, it is preferable that the skin material is laminated and integrated on each of both surfaces in the thickness direction of the foamed molded product.
The skin material is not particularly limited, and examples thereof include fiber reinforced plastics, metal sheets, and synthetic resin films. Of these, fiber reinforced plastic is preferred. A reinforced composite using a fiber reinforced plastic as a skin material is referred to as a fiber reinforced composite.
The reinforcing fibers constituting the fiber reinforced plastic include glass fibers, carbon fibers, silicon carbide fibers, alumina fibers, Tyranno fibers, basalt fibers, ceramic fibers and other inorganic fibers; stainless steel fibers, steel fibers and other metal fibers; aramid Organic fibers such as fibers, polyethylene fibers, polyparaphenylene benzoxador (PBO) fibers; and boron fibers. Reinforcing fibers may be used alone or in combination of two or more. Among these, carbon fiber, glass fiber, and aramid fiber are preferable, and carbon fiber is more preferable. These reinforcing fibers have excellent mechanical properties despite being lightweight.

The reinforcing fiber is preferably used as a reinforcing fiber substrate processed into a desired shape. Examples of the reinforcing fiber base material include woven fabrics, knitted fabrics, non-woven fabrics, and face materials obtained by binding (stitching) fiber bundles (strands) obtained by aligning reinforcing fibers in one direction with yarns. . Examples of the weaving method include plain weave, twill weave and satin weave. Examples of the yarn include a synthetic resin yarn such as a polyamide resin yarn and a polyester resin yarn, and a stitch yarn such as a glass fiber yarn.
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. For example, a laminated reinforcing fiber base material integrated (stitched) with is used.

The fiber reinforced plastic is obtained by impregnating a reinforced fiber with a synthetic resin. The reinforcing fibers are bonded and integrated by the impregnated synthetic resin.
The method of impregnating the reinforcing fiber with the synthetic resin is not particularly limited, and examples thereof include (1) a method of immersing the reinforcing fiber in the synthetic resin, and (2) a method of applying the synthetic resin to the reinforcing fiber.
As the synthetic resin impregnated into the reinforcing fiber, either a thermoplastic resin or a thermosetting resin can be used, and a thermosetting resin is preferably used. The thermosetting resin impregnated into the reinforcing fiber is not particularly limited, and is an epoxy resin, unsaturated polyester resin, phenol resin, melamine resin, polyurethane resin, silicone resin, maleimide resin, vinyl ester resin, cyanate ester resin, maleimide. Examples thereof include a resin obtained by prepolymerizing a resin and a cyanate ester resin, and an epoxy resin and a vinyl ester resin are preferable because they are excellent in heat resistance, shock absorption or chemical resistance. The thermosetting resin may contain additives such as a curing agent and a curing accelerator. In addition, a thermosetting resin may be used independently and 2 or more types may be used together.

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, acrylic resins, and the like. Polyester resins and thermoplastic epoxy resins are preferred because they are excellent in adhesiveness with the foamed molded article or adhesiveness between the reinforcing fibers constituting the fiber reinforced plastic. In addition, a thermoplastic resin may be used independently and 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 glycidyl amine 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 and 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 and 2 or more types may be used together.
The content of the synthetic resin in the fiber reinforced plastic is preferably 20 to 70% by weight. When the content is less than 20% by weight, the binding property between the reinforcing fibers and the adhesion between the fiber reinforced plastic and the foamed molded article are insufficient, and the mechanical properties of the fiber reinforced plastic and the mechanical strength of the fiber reinforced composite are obtained. May not be sufficiently improved. When the amount is more than 70% by weight, the mechanical properties of the fiber reinforced plastic may be lowered, and the mechanical strength of the fiber reinforced composite may not be sufficiently improved. The content is more preferably 30 to 60% by weight.
The thickness of the fiber reinforced plastic is preferably 0.02 to 2 mm, and more preferably 0.05 to 1 mm. A fiber reinforced plastic having a thickness within this range is excellent in mechanical properties despite being lightweight.
Basis weight of the fiber reinforced plastic is preferably ^{50~4000g / m 2, 100~1000g / m} 2 is more preferable. A fiber reinforced plastic having a basis weight within this range is excellent in mechanical properties despite being lightweight.

Next, a method for producing a reinforced composite will be described. The method for producing a reinforced composite by laminating and integrating the skin material on the surface of the foam molded body is not particularly limited. For example, (1) the skin material is laminated and integrated on the surface of the foam molded body via an adhesive. (2) A foam-molded article obtained by laminating a fiber-reinforced plastic forming material in which a reinforcing fiber is impregnated with a thermoplastic resin on the surface of the foam-molded article, and using the thermoplastic resin impregnated in the reinforcing fiber as a binder (3) Laminating a fiber reinforced plastic forming material in which a reinforcing fiber is impregnated with an uncured thermosetting resin on the surface of the foam molded body And a method of laminating and integrating the fiber reinforced plastic formed by curing the thermosetting resin with the thermosetting resin impregnated in the reinforcing fiber on the surface of the foam molded body (4) A skin material that is heated and softened is disposed on the surface of the foam molded body, and the skin material is deformed along the surface of the foam molded body as necessary by pressing the skin material against the surface of the foam molded body. However, a method of laminating and integrating on the surface of the foamed molded product, (5) a method generally applied in molding of fiber reinforced plastics, and the like can be mentioned. From the viewpoint that the foamed molded article is excellent in mechanical properties such as load resistance under a high temperature environment, the method (4) can also be suitably used.
Examples of the method used for molding the fiber reinforced plastic include an autoclave method, a hand layup method, a spray-up method, a PCM (Prepre Compression Molding) method, an RTM (Resin Transfer Molding) method, and a VaRTM (Vacuum Assisted Resin Transfer Transfer). Law.

The fiber reinforced composite thus obtained is excellent in heat resistance, mechanical strength and lightness. Therefore, it can be used in a wide range of applications such as the field of transportation equipment such as automobiles, airplanes, railway vehicles, ships, etc., the household appliances field, the information terminal field, and the furniture field.
For example, the fiber reinforced composite is composed of parts for transportation equipment, parts for transportation equipment including structural parts constituting the main body of transportation equipment (particularly parts for automobiles), windmill blades, robot arms, cushioning materials for helmets, It can be suitably used as an agricultural product box, a transport container such as a thermal insulation container, a rotor blade of an industrial helicopter, or a component packing material.
According to the present invention, there is provided an automotive part composed of the fiber-reinforced composite of the present invention. Examples of the automotive part include a floor panel, a roof, a bonnet, a fender, an under cover, a wheel, a steering wheel, Examples include containers (housings), hood panels, suspension arms, bumpers, sun visors, trunk lids, luggage boxes, seats, doors, cowls and the like.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the examples. First, measurement methods and evaluation methods in Examples and Comparative Examples will be described.

(Glass-transition temperature)
The glass transition temperature was measured by the method described in JIS K7121: 1987 “Method for measuring plastic transition temperature”. However, the sampling method and temperature conditions were as follows.
Using a differential scanning calorimeter device DSC 6220 type (manufactured by SII Nano Technology), about 6 mg of the sample was filled so that there was no gap at the bottom of the aluminum measurement container. The sample was heated from 30 ° C. to 220 ° C. at a temperature increase rate of 20 ° C./min under a nitrogen gas flow rate of 20 mL / min. From the DSC curve obtained when the sample was quickly removed after being held for 10 minutes, allowed to cool in an environment of 25 ± 10 ° C., and then heated from 30 ° C. to 220 ° C. at a temperature increase rate of 20 ° C./min. The glass transition temperature (starting point) was calculated. At this time, alumina is used as a reference material. The glass transition start temperature was determined from the standard (9.3 “How to determine the glass transition temperature”).

(Bulk density and bulk multiple)
The bulk density was measured in accordance with JIS K6911: 1995 “General Test Method for Thermosetting Plastics”. That is, it measured using the apparent density measuring device based on JISK6911, and measured the bulk density based on the following formula.
Bulk density of expanded particles (kg / m ³ ) = [weight of measuring cylinder containing sample (kg) −weight of measuring cylinder (kg)] / [capacity of measuring cylinder (m ³ )]
The bulk multiple is a value obtained by adding the resin density to the reciprocal of the bulk density.

(Bending test: density and maximum point load, stress, displacement and energy)
The load, stress, displacement, and energy at the maximum point were measured by a method in accordance with JIS K7221-1: 2006 “Rigid foamed plastic—Bending test—Part 1: Determination of deflection characteristics”. That is, a rectangular parallelepiped test piece having a length of 20 mm, a width of 25 mm, and a height of 130 mm was cut out from the foamed molded body. A Tensilon universal testing machine ("UCT-10T" manufactured by Orientec Co., Ltd.) was used for the measurement. The bending maximum point stress of the bending strength was calculated using a universal testing machine data processing system (“UTPS-237S Ver, 1.00” manufactured by Soft Brain).
The strip-shaped test piece was placed on a support, and the bending maximum point stress was measured under the conditions of a load cell 1000N, a test speed of 10 mm / min, a tip jig 5R of the support, and an opening width of 100 mm. The number of specimens shall be 5 or more, and the same as JIS K 7100: 1999 symbol “23/50” (temperature 23 ° C., relative humidity 50%) after adjusting the condition for 16 hours under a second grade standard atmosphere. Measurement was performed under a standard atmosphere. The arithmetic mean value of the bending maximum point stress of each test piece was taken as the bending maximum point stress of the foamed molded product.
Moreover, the bending maximum point stress per unit density was calculated by dividing the bending maximum point stress by the density of the foamed molded product.
The density (kg / m ³ ) of the foamed molded product was obtained from the formula (a) / (b) by measuring the weight (a) and volume (b) of the test piece cut out from the foamed molded product.

(Bending test: elastic modulus)
The flexural modulus was measured by a method in accordance with JIS K7221-1: 2006 “Rigid Foamed Plastics—Bending Test—Part 1: Determination of Flexural Properties”. That is, a rectangular parallelepiped test piece having a length of 20 mm, a width of 25 mm, and a height of 130 mm was cut out from the foamed molded body. A Tensilon universal testing machine ("UCT-10T" manufactured by Orientec Co., Ltd.) was used for the measurement. The flexural modulus was calculated using a universal testing machine data processing system (“UTPS-237S Ver, 1.00” manufactured by Soft Brain). The number of specimens shall be 5 or more, and the same as JIS K 7100: 1999 symbol “23/50” (temperature 23 ° C., relative humidity 50%) after adjusting the condition for 16 hours under a second grade standard atmosphere. Measurement was performed under a standard atmosphere. The arithmetic average value of the compression elastic modulus of each test piece was used as the bending elastic modulus of the foamed molded product.
The flexural modulus was calculated by the following equation using the first linear part of the load-deformation curve.
E = Δσ / Δε
E: Flexural modulus (MPa)
Δσ: Stress difference between two points on the straight line (MPa)
Δε: Difference in deformation between the same two points (%)
The flexural modulus per unit density was calculated by dividing the flexural modulus by the density of the foamed molded product.

(Compression test: density and 5%, 10% and 25% stress)
The 5% compressive stress, 10% compressive stress, and 25% compressive stress of the foamed molded article were measured by the method described in JIS K7220: 2006 “Rigid Foamed Plastics—How to Obtain Compression Properties”. That is, using a Tensilon universal testing machine ("UCT-10T" manufactured by Orientec Co., Ltd.) and a universal testing machine data processing system ("UTPS-237S Ver, 1.00" manufactured by Softbrain), the specimen size cross section is 50 mm. The compression strength (5% deformation compression stress, 25% deformation compression stress, compression elastic modulus) was measured at 50 mm, thickness 25 mm, and compression speed of 2.5 mm / min. The number of specimens shall be 5 or more, and the same as JIS K 7100: 1999 symbol “23/50” (temperature 23 ° C., relative humidity 50%) after adjusting the condition for 16 hours under a second grade standard atmosphere. Measurements were performed under a standard atmosphere. The arithmetic mean values of the compressive strength (5% deformation compression stress, 10% deformation compression stress, 25% deformation compression stress) of each test piece are respectively 5% compression stress, 10% compression stress, and 25% of the foam molded article. Compressive stress was assumed.
(5% (10%, 25%) deformation compressive stress)
5% (10%, 25%) deformation compressive stress was calculated by the following equation. In addition, the inside of () is conditions when calculating 10% deformation compressive stress and 25% deformation compressive stress.
σ5 (10, 25) = F5 (10, 25) / A ₀
σ5 (10, 25): 5% (10%, 25%) Deformation compressive stress (MPa)
F5 (10, 25): 5% (10%, 25%) Deformation force (N)
A ₀ : Initial cross-sectional area of the test piece (mm ² )
The 5% deformation compressive stress per unit density was calculated by dividing the 5% deformation compressive stress by the density of the foamed molded product.

(Compression test: elastic modulus)
The compression elastic modulus of the foamed molded product was measured by the method described in JIS K7220: 2006 “Hard foamed plastic-Determination of compression characteristics”. That is, using a Tensilon universal testing machine ("UCT-10T" manufactured by Orientec Co., Ltd.) and a universal testing machine data processing system ("UTPS-237S Ver, 1.00" manufactured by Softbrain), the specimen size cross section is 50 mm. The compression elastic modulus was measured with × 50 mm, thickness 25 mm, and compression speed of 2.5 mm / min. The number of specimens shall be 5 or more, and the same as JIS K 7100: 1999 symbol “23/50” (temperature 23 ° C., relative humidity 50%) after adjusting the condition for 16 hours under a second grade standard atmosphere. Measurements were performed under a standard atmosphere. The arithmetic average value of the compression elastic modulus of each test piece was used as the compression elastic modulus of the foamed molded article.
(Compressive modulus)
The compression elastic modulus was calculated by the following equation using the first linear portion of the load-deformation curve.
E = Δσ / Δε
E: Compression modulus (MPa)
Δσ: Stress difference between two points on the straight line (MPa)
Δε: Difference in deformation between the same two points (%)
Further, the compression elastic modulus per unit density was calculated by dividing the compression elastic modulus by the density of the foamed molded product.

(Ratio of resin component of base resin)
⁽¹ H-NMR)
Measurement was performed under the following conditions using an ECX400P nuclear magnetic resonance apparatus manufactured by JEOL.
<Measurement conditions>
・ Measurement mode Single pulse ・ Pulse width 45 ° (6.05μsec)
・ Number of points 32k
・ Repetition time: 7.0 seconds ・ Number of integrations: 128 times ・ Measurement solvent: Deuterated chloroform ・ Sample concentration: Approx. 20 mg / 0.6 mL
・ Measurement temperature 50 ℃
・ Chemical shift standard Chloroform: 7.24ppm
・ Measurement range 20ppm (-5ppm to 15ppm)
・ Window function exponnential (BF: 0.12 Hz)
The composition ratio of the base resin was calculated from the integral intensity ratio of each signal of the spectrum obtained from ¹ H-NMR measurement. In addition, when signals presumed to be derived from impurities were observed in each signal region, these contributions were ignored in the calculation.

(FT-IR)
The absorbance ratio (D1780 / D698, D1720 / D698) of the base resin was measured as follows.
Each of 10 randomly selected resin particles was subjected to surface analysis by an infrared spectroscopic analysis ATR measurement method to obtain an infrared absorption spectrum. In this analysis, an infrared absorption spectrum having a depth ranging from the sample surface to several μm (about 2 μm) was obtained. The absorbance ratio (D1780 / D698, D1720 / D698) was calculated from each infrared absorption spectrum, and the arithmetic average of the calculated absorbance ratio was used as the absorbance ratio.
Absorbances D1780, D1720, and D698 were connected to Thermo SCIENTIFIC's “Smart-iTR” as an ATR accessory to a measuring device sold under the trade name “Fourier transform infrared spectrophotometer Nicolet iS10” by Thermo SCIENTIFIC. It was measured. Infrared spectroscopic analysis ATR measurement was performed under the following conditions.

<Measurement conditions>
Measurement apparatus: Fourier transform infrared spectrophotometer Nicolet iS10 (manufactured by Thermo SCIENTIFIC) and single reflection type horizontal ATR Smart-iTR (manufactured by Thermo SCIENTIFIC)
ATR crystal: Diamond with ZnSe lens, angle = 42 °
・ Measuring method: Single ATR method ・ Measured wave number range: 4000 cm ^{−1 to} 650 cm ⁻¹
Wavelength dependence of measurement depth: not corrected Detector: Triglycine deuterated sulfate (DTGS) detector and KBr beam splitter Resolution: 4 cm ^-1
・ Number of integration: 16 times (same for background measurement)
In the ATR method, the intensity of the infrared absorption spectrum obtained by the measurement changes depending on the degree of adhesion between the sample and the high refractive index crystal, so the degree of adhesion is almost uniform by applying the maximum load that can be applied with the “Smart-iTR” of the ATR accessory. The measurement was performed.
The infrared absorption spectrum obtained under the above conditions was subjected to peak processing as follows to obtain D1780, D1720, and D698, respectively.
The absorbance D1780 at 1780 cm ⁻¹ obtained from the infrared absorption spectrum is the absorbance corresponding to the absorption spectrum derived from the antisymmetric stretching vibration due to C═O of the two carbonyl groups in maleic anhydride.
In this absorbance measurement, peak separation was not performed even when other absorption spectra overlapped at 1780 cm ⁻¹ . Absorbance D1780 is a straight line connecting the 1920Cm ^-1 and 1620 cm ^-1 as a baseline, means the maximum absorbance between 1810 cm ^-1 and 1745 cm ^-1.

Further, the absorbance D1720 at 1720 cm ⁻¹ is an absorbance corresponding to an absorption spectrum derived from an antisymmetric stretching vibration caused by a carbonyl group C═O contained in methyl methacrylate.
In this measurement of absorbance, peak separation is not performed even if other absorption spectra overlap at 1720 cm ⁻¹ . Absorbance D1720 is a straight line connecting the 1920Cm ^-1 and 1620 cm ^-1 as a baseline, means the maximum absorbance between 1745 cm ^-1 and 1690 cm ^-1.
Absorbance D698 at 698 cm ⁻¹ is an absorbance corresponding to an absorption spectrum derived from an out-of-plane bending vibration of C—H in a monosubstituted benzene ring in styrene.
In this absorbance measurement, peak separation is not performed even when other absorption spectra overlap at 698 cm ⁻¹ . Absorbance D698 is a straight line connecting the 1510 cm ^-1 and 810 cm ^-1 as a baseline, means the maximum absorbance between 720 cm ^-1 and 660 cm ^-1.

Styrene, methyl methacrylate, and maleic anhydride ratios (mass%) were calculated from absorbance ratios (D1780 / D698, D1720 / D698) based on a calibration curve described later. In addition, the peak processing method used the method similar to the above-mentioned resin particle.
As a method for determining the composition ratio of styrene and methyl methacrylate from the absorbance ratio, a plurality of types of standard samples prepared by uniformly mixing styrene resin and methyl methacrylate resin at a predetermined composition ratio were prepared.
Specifically, monomers measured by weight ratios of methyl methacrylate and styrene at a weight ratio of 0/100, 20/80, 40/60, 50/50, and 60/40, respectively, are placed in a 10 ml screw vial. 10 parts by weight of 2,2′-azobis (2,4-dimethylvaleronitrile) was added to 100 parts by weight of the monomer to dissolve the monomer. The obtained liquid mixture is transferred to a 2 ml sample tube (φ7 mm × 122 mm × 190 mm), purged with nitrogen and sealed. Next, this was put into a water bath set at 65 ° C. and heated for 10 hours to complete the polymerization, and the polymer taken out from the ampule was used as a standard sample.
After obtaining an infrared absorption spectrum for each standard sample by the infrared spectroscopic analysis ATR method, an absorbance ratio (D1780 / D698) is calculated. The calibration curve is drawn by taking the composition ratio (styrene resin ratio in the standard sample = mass%) on the vertical axis and the absorbance ratio (D1780 / D698) on the horizontal axis. Based on this calibration curve, the composition ratio of the styrene resin and the methyl methacrylate resin could be determined.

As standard samples of styrene resin and maleic anhydride resin, a 1/1 copolymer of styrene and maleic anhydride (trade name “SMA1000 (P)”, manufactured by CRAY VALLEY) and 3 of styrene and maleic anhydride are used. / 1 copolymer (trade name “SMA3000 (P)”, manufactured by CRAY VALLEY) was used.
After obtaining an infrared absorption spectrum for each standard sample by the infrared spectroscopic analysis ATR method, an absorbance ratio (D1720 / D698) was calculated. A calibration curve was drawn by taking the composition ratio (styrene resin ratio in the standard sample = mass%) on the vertical axis and the absorbance ratio (D1720 / D698) on the horizontal axis. Based on this calibration curve, the composition ratio of styrene resin and maleic anhydride resin could be determined.
The composition ratios of styrene and methyl methacrylate and styrene and maleic anhydride were determined from the calibration curves. From each composition ratio, the composition ratio of the three components of styrene, methyl methacrylate, and maleic anhydride in the resin was determined by the following procedure.
Here, the ratio of each standard sample was set as follows.
Methyl methacrylate: styrene = A: B [1]
Styrene: maleic anhydride = C: D [2]
Since styrene is a common term, the styrene ratio C in [2] was matched with the styrene ratio B in [1].
From [2] Styrene: Maleic anhydride = C: D
= C x (B / C): D x (B / C)
= B: D × (B / C) [3]
From [3], since the ratio of styrene is equal to [1], the abundance ratios of methyl methacrylate, styrene, and maleic anhydride are as follows from [1] and [3].
Methyl methacrylate: styrene: maleic anhydride = A: B: D × (B / C) [4]
From the abundance ratio of [4], the ratio of each component was as follows.
Methyl methacrylate = {A / ((A + B + D × (B / C))} × 100
Styrene = {B / ((A + B + D × (B / C))} × 100
Maleic anhydride = {D × (B / C) / ((A + B + D × (B / C))} × 100

(Bubble count)
The number of bubbles in the expanded particles and the expanded molded body was measured in the following manner. First, an area of 11.9 mm ² was photographed at 30 times with a scanning electron microscope (“SU1510” manufactured by Hitachi High-Technologies Corporation) on the cut surface. For the foamed particles, the central part of the cross-section substantially divided into two at the central part of the foamed particles was taken. The photographed image was printed on A4 paper, and the average bubble diameter was calculated for all bubbles. In addition, the bubble diameter measured the long diameter and short diameter of the bubble cross section, and made it the value obtained by the arithmetic mean value of a short diameter and a long diameter. Specifically, two arbitrary points having the maximum mutual distance on the outer contour line of the bubble cross section were selected, and the distance between the two points was defined as the “bubble major diameter”. Also, any two points where the mutual distance is maximum are selected from any two points where the straight line perpendicular to the major axis of the bubble and the outer contour line of the bubble cross section intersect, and the distance between the two points is expressed as “ The short diameter of the bubbles ”. The number of individual bubbles was counted on the paper for small bubbles having a bubble diameter of 50 μm or more and less than 300 μm and large bubbles having a bubble diameter of 300 μm or more and 2 mm or less.
Each of the nine foam particles and the molded foam is cut in the same manner as described above to obtain enlarged photographs, and based on these enlarged photographs, the number of small bubbles and the individual bubbles of large bubbles are obtained in the same manner as described above. Numbers were calculated. The arithmetic average value of 10 individual bubbles was defined as the number of bubbles.

Example 1
(Resin particle manufacturing process)
Styrene-methyl methacrylate-maleic anhydride copolymer (trade name “DENKA RESISFY R-310”, Denka Co., Ltd., styrene: 62 parts by weight, methyl methacrylate: 12 parts by weight, maleic anhydride: 26 parts by weight, density 1.15 g / cm ³ ) 100 parts by weight was supplied to a single screw extruder having a diameter of 40 mm at a rate of 10 kg / hr per hour, and melt kneaded at 270 ° C. Subsequently, about 70 ° C. cooling water is supplied from the die hole (5 nozzles with a diameter of 0.8 mm arranged) of the die (temperature: 285 ° C., inlet side resin pressure: 13 MPa) attached to the tip of the single screw extruder. The resin particles were produced by extruding into the housed chamber, rotating the rotary shaft of the rotary blade having six cutting blades at a rotational speed of 5000 rpm, cutting into granules, cooling with the cooling water, and dehydrating and drying. . The obtained resin particles had an average particle diameter of 1.2 mm.

(Impregnation process)
After 100 parts by weight of the resin particles were sealed in a pressure vessel and the inside of the pressure vessel was replaced with carbon dioxide, carbon dioxide was injected to an impregnation pressure (gauge pressure) of 0.7 MPa. After leaving still at 20 degreeC environment and 24 hours of impregnation time passed, the pressure vessel was pressure-removed slowly over 5 minutes. In this way, resin particles were impregnated with carbon dioxide gas to obtain expandable particles.
(Foaming process)
Immediately after the pressure removal in the impregnation step, the foamable particles were taken out from the pressure vessel, and 0.1 parts by weight of ethylenebisstearic acid amide was added and mixed. Thereafter, the impregnated product was foamed with water vapor in a high-pressure foaming tank while being stirred with water vapor at a foaming temperature of 143 ° C. for 50 seconds. After foaming, drying was performed with an air dryer to obtain foamed particles. When the bulk density of the obtained foamed particles was measured by the method described above, it was 102 kg / m ³ (foaming ratio 10 times).
(Molding process)
The obtained expanded particles were allowed to stand at room temperature (23 ° C.) for 1 day, and then sealed in a pressure vessel. After the inside of the pressure vessel was replaced with carbon dioxide, carbon dioxide was impregnated with an impregnation pressure (gauge pressure). Press-fitted to 5 MPa. It left still in a 20 degreeC environment, and pressure curing was implemented for 8 hours. After taking out, it is filled in a 30 mm x 300 mm x 400 mm mold, heated with 0.38 MPa water vapor for 20 seconds, and then cooled until the maximum surface pressure of the foamed molded product is reduced to 0.05 MPa. Thus, a foamed molded product was obtained.

(Example 2)
(Foaming step) In the same manner as in Example 1 except that 0.15 parts by weight of ethylenebisstearic acid amide was added and the mixture was foamed with stirring at a foaming temperature of 143 ° C. for 60 seconds. Foamed particles and a foamed molded product of m ³ (foaming ratio 20 times) were obtained.

(Example 3)
(Foaming step) In the same manner as in Example 1 except that 0.15 parts by weight of ethylenebisstearic acid amide was added and the foaming temperature was 143 ° C. while stirring for 55 seconds, the foaming density was 74 kg / kg. Foamed particles and a foamed molded product of m ³ (foaming ratio 15 times) were obtained.

(Comparative Example 1)
(Resin particle manufacturing process)
Styrene-methyl methacrylate-maleic anhydride copolymer (trade name “DENKA RESISFY R-310”, Denka Co., Ltd., styrene: 62 parts by weight, methyl methacrylate: 12 parts by weight, maleic anhydride: 26 parts by weight, density 1.15 g / cm ³ ) 100 parts by weight was supplied to a twin screw extruder having a diameter of 30 mm at a rate of 6 kg / hr per hour, and melt kneaded at 250 ° C. Subsequently, the resin composition was extruded from each nozzle of a multi-nozzle mold (20 nozzles having a diameter of 1.0 mm arranged in a circle) attached to the front end of the twin-screw extruder. The extruded resin was immediately cooled in a cooling water bath. The cooled strand-shaped resin was sufficiently drained and then cut into small particles using a pelletizer to produce resin particles. The obtained resin particles had a particle length L of 1.3 to 1.8 mm and a particle diameter D of 1.0 to 1.2 mm.
Except for using the obtained resin particles, it was subjected to (impregnation step), (foaming step) and (molding step) in the same manner as in Example 1, and the foamed density was 108 kg / m ³ (foaming ratio: 10 times). A foamed molded product was obtained.

(Comparative Example 2)
(Foaming step) In the same manner as in Comparative Example 1 except that 0.15 parts by weight of ethylenebisstearic acid amide was added and the foaming temperature was 143 ° C. while stirring for 60 seconds, the foaming density was 60 kg / m ³ (expanding ratio 20 times) expanded particles were obtained.
Except using the obtained resin particle, it attached | subjected to (molding process) like Example 1, and obtained the foaming molding.
Table 1 summarizes the physical properties of the foamed particles and foamed molded products of Examples 1 to 3 and Comparative Examples 1 and 2.
Moreover, the cross-sectional photograph of the foamed particle of Examples 1-3 and Comparative Examples 1-2 and a foaming molding is shown to FIG. 1 and 2, respectively.

  From Table 1, it can be seen that the foamed molded product obtained from the foamed particles having a specific range of bubbles has excellent mechanical properties.

Example 4
(Resin particle manufacturing process)
Styrene-methyl methacrylate-maleic anhydride copolymer (trade name “DENKA RESISFY R-200”, manufactured by Denka Co., Ltd., styrene: 55 parts by weight, methyl methacrylate: 26 parts by weight, maleic anhydride: 19 parts by weight, density 1.16 g / cm ³ ) 100 parts by weight was supplied to a single screw extruder having a diameter of 40 mm at a rate of 10 kg / hr per hour, and melt kneaded at 260 ° C. Subsequently, cooling water at about 70 ° C. was poured from the die hole (five nozzles with a diameter of 0.8 mm arranged) of the die (temperature: 280 ° C., inlet side resin pressure: 14 MPa) attached to the tip of the single screw extruder. The resin particles were produced by extruding into the housed chamber, rotating the rotary shaft of the rotary blade having six cutting blades at a rotational speed of 5000 rpm, cutting into granules, cooling with the cooling water, and dehydrating and drying. . The obtained resin particles had an average particle diameter of 1.2 mm.

(Impregnation process)
After 100 parts by weight of the resin particles were sealed in a pressure vessel and the inside of the pressure vessel was replaced with carbon dioxide, carbon dioxide was injected to an impregnation pressure (gauge pressure) of 0.7 MPa. After leaving still at 20 degreeC environment and 24 hours of impregnation time passed, the pressure vessel was pressure-removed slowly over 5 minutes. In this way, resin particles were impregnated with carbon dioxide gas to obtain expandable particles.
(Foaming process)
Immediately after the pressure removal in the impregnation step, the foamable particles were taken out from the pressure vessel, and then 0.1 part by weight of ethylenebisstearic acid amide was added and mixed. Thereafter, the impregnated product was foamed with water vapor in a high-pressure foaming tank while being stirred at a foaming temperature of 131 ° C. for 50 seconds using water vapor. After foaming, drying was performed with an air dryer to obtain foamed particles. When the bulk density of the obtained foamed particles was measured by the method described above, it was 105 kg / m ³ (foaming ratio 10 times).
(Molding process)
The obtained expanded particles were allowed to stand at room temperature (23 ° C.) for 1 day, and then sealed in a pressure vessel. After the inside of the pressure vessel was replaced with carbon dioxide, carbon dioxide was impregnated with an impregnation pressure (gauge pressure). Press-fitted to 5 MPa. It left still in a 20 degreeC environment, and pressure curing was implemented for 8 hours. After removal, fill a 30 mm x 300 mm x 400 mm molding die, heat with 0.30 MPa water vapor for 20 seconds, and then cool until the maximum surface pressure of the foamed molded product drops to 0.05 MPa. Thus, a foamed molded product was obtained.

(Example 5)
(Foaming step) In the same manner as in Example 4 except that 0.15 parts by weight of ethylenebisstearic acid amide was added and the mixture was foamed with stirring at a foaming temperature of 131 ° C. for 70 seconds. Foamed particles and a foamed molded product of m ³ (foaming ratio 20 times) were obtained.
Table 2 summarizes the physical properties of the foamed particles and foamed molded products of Examples 4 and 5 above.
Moreover, the cross-sectional photograph of the expanded particle of Example 4 and 5 and a foaming molding is shown in FIG.

  From Table 2, it can be seen that the foamed molded product obtained from the foamed particles having a specific range of bubbles has excellent mechanical properties.

(Example 6)
(Resin particle manufacturing process)
Styrene-methyl methacrylate-maleic anhydride copolymer (trade name “DENKA RESISFY R-310”, Denka Co., Ltd., styrene: 62 parts by weight, methyl methacrylate: 12 parts by weight, maleic anhydride: 26 parts by weight, density 1.15 g / cm ³ ) 100 parts by weight is 85 parts by weight, and the remaining 15 parts by weight is a styrene-maleic anhydride-N-phenylmaleimide copolymer (trade name “DENKA IP MS-NIP”, manufactured by Denka Corporation, Styrene: 58 parts by weight, maleic anhydride: 4 parts by weight, N-phenylmaleimide: 38 parts by weight, density 1.18 g / cm ³ , glass transition temperature Tg 186 ° C.), 100 parts by weight of 10 kg / hr per hour The mixture was supplied to a single screw extruder having a diameter of 40 mm and melt-kneaded at 270 ° C. Subsequently, about 70 ° C. cooling water is supplied from a die hole (5 nozzles with a diameter of 0.8 mm arranged) of a die (temperature: 285 ° C., inlet side resin pressure: 14 MPa) attached to the tip of the single screw extruder. The resin particles were produced by extruding into the housed chamber, rotating the rotary shaft of the rotary blade having six cutting blades at a rotational speed of 5000 rpm, cutting into granules, cooling with the cooling water, and dehydrating and drying. . The obtained resin particles had an average particle diameter of 1.2 mm.

(Impregnation process)
After 100 parts by weight of the resin particles were sealed in a pressure vessel and the inside of the pressure vessel was replaced with carbon dioxide, carbon dioxide was injected to an impregnation pressure (gauge pressure) of 0.7 MPa. After leaving still at 20 degreeC environment and 24 hours of impregnation time passed, the pressure vessel was pressure-removed slowly over 5 minutes. In this way, resin particles were impregnated with carbon dioxide gas to obtain expandable particles.
(Foaming process)
Immediately after the pressure removal in the impregnation step, the foamable particles were taken out from the pressure vessel, and 0.1 parts by weight of ethylenebisstearic acid amide was added and mixed. Thereafter, the impregnated product was foamed with water vapor in a high-pressure foaming tank while stirring for 80 seconds at a foaming temperature of 145 ° C. using water vapor. After foaming, drying was performed with an air dryer to obtain foamed particles. When the bulk density of the obtained expanded particles was measured by the method described above, it was 104 kg / m ³ (expanding ratio 10 times).
(Molding process)
The obtained expanded particles were allowed to stand at room temperature (23 ° C.) for 1 day, and then sealed in a pressure vessel. After the inside of the pressure vessel was replaced with carbon dioxide, carbon dioxide was impregnated with an impregnation pressure (gauge pressure). Press-fitted to 5 MPa. It left still in a 20 degreeC environment, and pressure curing was implemented for 8 hours. After removal, it is filled into a 30 mm x 300 mm x 400 mm mold, heated with 0.45 MPa water vapor for 20 seconds, and then cooled until the maximum surface pressure of the foamed molded product drops to 0.05 MPa. Thus, a foamed molded product was obtained.

(Example 7)
(Foaming step) In the same manner as in Example 6 except that 0.15 parts by weight of ethylenebisstearic acid amide was added and the foaming temperature was 145 ° C. with stirring for 90 seconds, the foaming density was 72 kg / kg. Foamed particles and a foamed molded product of m ³ (foaming ratio 15 times) were obtained.

(Example 8)
(Foaming step) In the same manner as in Example 6 except that 0.15 parts by weight of ethylenebisstearic acid amide was added and the foaming temperature was 145 ° C. while stirring for 100 seconds, the foaming density was 47 kg / kg. Foamed particles and a foamed molded product of m ³ (foaming ratio 20 times) were obtained.
Table 3 summarizes the physical properties of the foamed particles and foamed molded products of Examples 6-8.
Moreover, the cross-sectional photograph of the foamed particle of Examples 6-8 and a foaming molding is shown in FIG.

  From Table 3, it can be seen that the foam molded product obtained from the expanded particles having a specific range of bubbles has excellent mechanical properties.

Claims (9)

Expanded particles composed of a base resin containing a copolymer of aromatic vinyl, (meth) acrylic acid ester, and unsaturated dicarboxylic acid, and the expanded particles have an area of 11.9 mm ² by 30 times A foamed particle comprising: a small bubble having a bubble diameter of 50 μm or more and less than 300 μm and a large bubble having a bubble diameter of 300 μm or more and 2 mm or less.   The foamed particle according to claim 1, wherein the foamed particle has only one of the large bubbles.   The aromatic vinyl is a styrene monomer, the (meth) acrylic acid ester is a (meth) acrylic acid alkyl ester (the alkyl group has 1 to 5 carbon atoms), and the unsaturated dicarboxylic acid has 2 to 6 carbon atoms. Selected from aliphatic unsaturated dicarboxylic acids, and the copolymer is 100 parts by weight of the total of units derived from the aromatic vinyl, (meth) acrylic acid ester and unsaturated dicarboxylic acid, 30 to 80 parts by weight of units derived from the aromatic vinyl, 8 to 35 parts by weight of units derived from the (meth) acrylic acid ester, and 10 to 50 parts by weight of units derived from the unsaturated dicarboxylic acid The expanded particle according to claim 1 or 2. It is a foam molded article composed of a base resin containing a copolymer of aromatic vinyl, (meth) acrylic acid ester, and unsaturated dicarboxylic acid, and the foam molded article is composed of a plurality of the foamed particles. In the cross-sectional photograph obtained by photographing the area of 11.9 mm ² at 30 times, the expanded particles include small bubbles having a bubble diameter of 50 μm or more and less than 300 μm and large bubbles having a bubble diameter of 300 μm or more and 2 mm or less. Foam molded article characterized by   The foamed molded product according to claim 4, wherein the foamed particles have only one large cell in one of them.   The aromatic vinyl is a styrene monomer, the (meth) acrylic acid ester is a (meth) acrylic acid alkyl ester (the alkyl group has 1 to 5 carbon atoms), and the unsaturated dicarboxylic acid has 2 to 6 carbon atoms. Each selected from an aliphatic unsaturated dicarboxylic acid, and the copolymer is 100 parts by weight of the total of units derived from the aromatic vinyl, (meth) acrylic acid ester and unsaturated dicarboxylic acid, 30 to 80 parts by weight of units derived from the aromatic vinyl, 8 to 35 parts by weight of units derived from the (meth) acrylic acid ester, and 10 to 50 parts by weight of units derived from the unsaturated dicarboxylic acid The foaming molding of Claim 4 or 5.   A fiber reinforced composite comprising the foam molded article according to any one of claims 4 to 6 and a fiber reinforced plastic layer laminated and integrated on a surface of the foam molded article.   The fiber reinforced composite according to claim 7, which is used for a wind turbine blade, a robot arm, and an automobile part.   The automotive part comprised from the foaming molding of any one of Claims 4-6, or the fiber reinforced composite_body | complex of Claim 7.