JP2019001980A - Aromatic vinyl resin composition for producing expanded particles and use thereof - Google Patents

Abstract

To provide a resin composition that makes it possible to give a foam molding showing excellent mechanical properties.SOLUTION: An aromatic vinyl resin composition for the production of foamed particles, contains a base material resin in which a copolymer of aromatic vinyl, (meth)acrylate, and unsaturated dicarboxylic acid is blended with polylactic acid.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an aromatic vinyl resin composition for producing expanded particles and its use. More specifically, the present invention relates to an aromatic vinyl-based resin composition capable of providing a foamed molded article having improved mechanical properties, foamed particles obtained therefrom, a foamed molded article, a fiber reinforced composite, and an automotive part.

Currently, foam molded articles obtained by foam molding of foamed particles using a styrene-based resin as a base resin are widely used in applications such as heat insulating materials and buffer materials.
By the way, since styrene-type resin has low heat resistance, there existed a subject that it was not suitable for the use exposed to high temperature.
In order to solve this problem, for example, in Japanese Patent Application Laid-Open No. 2016-37522 (Patent Document 1), by copolymerizing styrene, (meth) acrylic acid ester, and unsaturated dicarboxylic acid, Technologies for improving heat resistance have been proposed.

JP 2016-37522 A

  However, the foamed molded article of Patent Document 1 has high brittleness and insufficient mechanical properties. Therefore, it has been desired to provide a foamed molded article having improved mechanical properties.

  The inventor of the present invention may improve the mechanical properties by adding another type of resin to the copolymer of aromatic vinyl, (meth) acrylic acid ester, and unsaturated dicarboxylic acid. As a result of repeating the test under the above idea, the present inventors have unexpectedly found that polylactic acid is effective in improving the mechanical properties, and have reached the present invention.

  Thus, according to the present invention, there is provided an aromatic vinyl resin composition for producing expanded particles, wherein the aromatic vinyl resin composition comprises an aromatic vinyl, a (meth) acrylic acid ester, and an unsaturated dicarboxylic acid. An aromatic vinyl resin composition for producing foamed particles is provided, which comprises a base resin obtained by adding polylactic acid to a copolymer of

  Further, according to the present invention, the foamed particle is composed of a plurality of bubbles and a cell wall partitioning the cells, and the cell wall is derived from the aromatic vinyl resin composition for producing the foamed particle. Expanded particles are provided.

Furthermore, according to this invention, the foaming molding obtained by carrying out foam molding of the said foaming particle is provided.
Also provided is a fiber reinforced composite comprising the above foam molded article and a fiber reinforced plastic layer laminated and integrated on the surface of the foam molded article.
Furthermore, 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 aromatic vinyl-type resin composition which can manufacture the foaming molding which shows the outstanding mechanical characteristic, 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) A copolymer and polylactic acid are contained in the base resin at 95: 5 to 55:45 (mass%).
(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. Each selected from aliphatic unsaturated dicarboxylic acids, and the copolymer is aromatic when the total of units derived from three of vinyl, (meth) acrylic acid ester and unsaturated dicarboxylic acid is 100 parts by mass. 30 to 80 parts by mass of units derived from vinyl, 8 to 35 parts by mass of units derived from (meth) acrylic acid ester, and 10 to 50 parts by mass of units derived from unsaturated dicarboxylic acid.

3 is a graph showing the flexural modulus of the resin particles of Example 1. 3 is a graph showing the melt tension of the resin particles of Example 1. It is the schematic of the manufacturing apparatus of the expanded particle of this invention. It is the schematic of the nozzle part in the manufacturing apparatus of FIG.

(Aromatic vinyl resin composition)
An aromatic vinyl-based resin composition for producing expanded particles (hereinafter also simply referred to as a resin composition) is obtained by adding polylactic acid to a copolymer of aromatic vinyl, (meth) acrylic acid ester, and unsaturated dicarboxylic acid. It is comprised from the base resin which added. The resin composition usually has a particulate shape. The total proportion of the copolymer and polylactic acid in the base resin is preferably 70% by mass or more, more preferably 85% by mass or more, and may be 100% by mass.
The copolymer and polylactic acid are preferably contained in the base resin at 95: 5 to 55:45 (mass%). If the copolymer content is greater than 95% by mass, the effect of improving the mechanical properties may be insufficient. If it is less than 55% by mass, the effect of improving the heat resistance may be insufficient.

The content ratio of the copolymer and polylactic acid is more preferably in the following range. That is, for example, the copolymer and polylactic acid are kneaded and strand-cut under a known condition in increments of 10% by mass to obtain a resin composition. In the case of only the copolymer and only polylactic acid, the resin composition is obtained by kneading and strand cutting under the same conditions as described above. The bending elastic modulus and melt tension of the resin composition are measured. Here, when the strand cannot be cut, the value is not measured. The obtained measurement values are plotted on the vertical axis, and the polylactic acid content ratio is plotted on the horizontal axis. A straight line connecting the two plots of the minimum and maximum polylactic acid content that can be graphed is entered in the graph. An example of such a graph is shown in FIGS.
In the graph showing the flexural modulus, the plot between the minimum and maximum polylactic acid content ratio may be located above the straight line. This means that the content ratio of polylactic acid between the content ratios is a so-called synergistic ratio. The inventor believes that the reason for the synergistic effect is that the copolymer and polylactic acid are crosslinked. The range of the ratio showing the synergistic effect is, for example, 90:10 to 30:70 in FIG. Moreover, it is preferable that a bending elastic modulus shows a value 50 MPa or more higher than the corresponding value of the polylactic acid content ratio in a straight line. In addition, it is preferable that the upper limit of a bending elastic modulus is 3800 MPa.

Here, the method for determining the range of the polylactic acid content ratio showing a synergistic effect based on the flexural modulus can be expressed more generally as follows.
(Determination method A)
(i) By measuring the flexural modulus of various polylactic acid content ratios, a graph represented by a plurality of plots with the flexural modulus as the vertical axis and the polylactic acid content ratio as the horizontal axis was obtained. Write a straight line connecting the two plots of the minimum and maximum polylactic acid content ratios,
(ii) The content ratio of polylactic acid in the aromatic vinyl resin composition is in a range where the measured value of the flexural modulus is 50 MPa or more higher than the value on the straight line corresponding to the measured value.
(Determination method B)
The content ratio of polylactic acid in the aromatic vinyl resin composition is
(i) Measure the flexural modulus when the content ratio of polylactic acid is 0% by mass and 80% by mass, and connect the two obtained points with a straight line,
(ii) When the polylactic acid content ratio is an arbitrary value on a straight line, the bending elastic modulus of the aromatic vinyl resin composition is within a range in which the value is 50 MPa or more higher than that on the straight line.

(Determination method C)
The content ratio of polylactic acid in the aromatic vinyl resin composition is
(i) Measure the flexural modulus when the polylactic acid content ratio is 0 mass% and 80 mass%,
(ii) plot the above two measured values on a graph with the flexural modulus as the vertical axis and the polylactic acid content ratio as the horizontal axis,
(iii) Write a straight line connecting the two measured value plots in the graph,
(iv) measuring the flexural modulus in various cases where the polylactic acid content ratio is between 0% and 80% by weight, and plotting the measured values on a graph;
(v) It is set within the range obtained by searching the range of polylactic acid content ratio showing a value higher by 50 MPa or more than the value of the flexural modulus on the straight line corresponding to the measured value from various measured values.

In the graph showing the melt tension, when an approximation curve by polynomial approximation of degree 3 is drawn from the plot, an inflection point may be shown in the approximation curve. For example, in FIG. 2, an inflection point exists in the vicinity of 30% by mass of polylactic acid. The reason for the presence of inflection points is that when polylactic acid is added, the decrease in melt tension can be suppressed by crosslinking, but if the content ratio of polylactic acid is higher than the crosslinking point, the ratio of polylactic acid that does not crosslink becomes excessive and abrupt. The inventor believes that a decrease in melt tension occurs. The content ratio of polylactic acid may be in the range of 10% by mass before and after the inflection point. For example, this range corresponds to a range of 20 to 40% by mass in FIG.
Here, the method for determining the range of the content ratio of polylactic acid exhibiting a synergistic effect based on the melt tension can be expressed more generally as follows.
(Determination method D)
(i) By measuring the melt tension of various polylactic acid content ratios, a graph represented by a plurality of plots with the melt tension as the vertical axis and the polylactic acid content ratio as the horizontal axis was obtained. Draw an approximate curve by polynomial approximation of 3,
(ii) determine the inflection point of the approximate curve,
(iii) The content ratio of polylactic acid in the aromatic vinyl resin composition is within the range of 10% by mass before and after the content ratio of polylactic acid corresponding to the inflection point.

(Determination method E)
The polylactic acid in the aromatic vinyl resin composition is
(i) Measure the melt tension in various cases where the content ratio of polylactic acid is between 0% and 80% by mass, and use the obtained various measured values in the graph to obtain an approximate curve by polynomial approximation of degree 3 To determine the inflection point,
(ii) Within the range of 10% by mass before and after the content ratio of polylactic acid corresponding to the inflection point.
(Determination method F)
The content ratio of polylactic acid in the aromatic vinyl resin composition is
(i) Measure the melt tension in various cases where the polylactic acid content ratio is between 0 wt% and 80 wt%, and plot the measured values in the graph,
(ii) Draw an approximate curve by polynomial approximation of degree 3 in the graph from various measured values, determine the inflection point,
(iii) Within the range obtained by searching the range of 10% by mass before and after the content ratio of polylactic acid corresponding to the inflection point.

(1) Copolymer The copolymer preferably has a glass transition temperature Tg of 115 to 160 ° C. When Tg is lower than 115 ° C., the foamed particles may shrink due to heating during foaming. When the temperature is higher than 160 ° C., the foamability of the foamed particles may be lowered, and the heat fusion integration between the foamed particles may be insufficient, and the mechanical properties of the foamed molded product may be degraded. 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 examples of the aromatic vinyl include styrene, vinyl toluene such as α-methylstyrene, ethyl styrene, i-propyl styrene, t-butyl styrene, dimethyl styrene, bromo styrene, chlorostyrene, and other styrene monofunctional monomers. , Divinylbenzene, trivinylbenzene, divinyltoluene, divinylxylene, bis (vinylphenyl) methane, bis (vinylphenyl) ethane, bis (vinylphenyl) propane, bis (vinylphenyl) butane, divinylnaphthalene, divinylanthracene, divinyl Examples include biphenyl, ethylene oxide adduct di (meth) acrylate of bisphenol A, and propylene oxide adduct di (meth) acrylate of bisphenol A. 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. When it is defined as parts by mass, 30 to 80 parts by mass of units derived from aromatic vinyl, 8 to 35 parts by mass of units derived from (meth) acrylic acid ester, and 10 to 50 parts by mass of units derived from unsaturated dicarboxylic acid It is preferable to include.
When the proportion of units derived from aromatic vinyl is less than 30 parts by mass, the foamability of the foamed particles is reduced at the time of foam molding, and the heat fusion integration between the foamed particles becomes insufficient, and Mechanical properties may be degraded. When this ratio is larger than 80 parts by mass, the heat resistance of the foamed molded product may be lowered. This ratio is more preferably 40 to 75 parts by mass, and further preferably 45 to 70 parts by mass.

When the proportion of units derived from (meth) acrylic acid esters is less than 8 parts by mass, the mechanical properties of the foamed molded product may be deteriorated. When this ratio is larger than 35 parts by mass, the foamability of the foamed particles is reduced at the time of foam molding, and the heat fusion integration between the foamed particles becomes insufficient, and the mechanical properties of the foamed molded product may be lowered. is there. This ratio is more preferably 10 to 33 parts by mass, and still more preferably 15 to 30 parts by mass.
When the ratio which the unit derived from unsaturated dicarboxylic acid accounts is less than 10 mass parts, the heat resistance of a foaming molding may fall. When this ratio is larger than 50 parts by mass, the foamability of the foamed particles is reduced during foam molding, and the heat fusion integration between the foamed particles becomes insufficient, and the mechanical properties of the foamed molded product may deteriorate. is there. This ratio is more preferably 15 to 40 parts by mass, and still more preferably 20 to 35 parts by mass.
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 mass or less, and may be 0% by mass.

(2) Polylactic acid The polylactic acid is preferably a polymer containing 50 mol% or more of lactic acid component units. Examples of polylactic acid include (i) a homopolymer of lactic acid, (ii) a copolymer of lactic acid and another aliphatic hydroxycarboxylic acid, (iii) lactic acid, an aliphatic polyhydric alcohol, and an aliphatic polycarboxylic acid. (Iv) a copolymer of lactic acid and an aliphatic polyhydric carboxylic acid, (v) a copolymer of lactic acid and an aliphatic polyhydric alcohol, (vi) the above (i) to (v) The mixture by any combination can be mentioned. Specific examples of the lactic acid include L-lactic acid, D-lactic acid, DL-lactic acid or their cyclic dimer L-lactide, D-lactide, DL-lactide or a mixture thereof. .
The polylactic acid may be crystalline or amorphous, and may be a mixture of crystalline polylactic acid and amorphous polylactic acid. By including crystalline polylactic acid, the mechanical properties of the foamed molded product can be further improved.

(3) Other resins Other resins 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.

  Among the other resins, the resin composition preferably contains polymethyl methacrylate. By containing poly (methyl methacrylate), the heat-fusibility of the foamed particles is improved, and the foamed particles having a further excellent mechanical property can be obtained by fusing the foamed particles more firmly. Can be obtained. 10-500 mass parts is preferable with respect to 100 mass parts of copolymers, as for content of polymethyl methacrylate in a resin composition, 20-450 mass parts is more preferable, and its 30-400 mass parts is especially preferable.

  It is preferable that the resin composition contains 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, making the thermal fusion between the foamed particles stronger, and further having excellent mechanical properties. 0.5-5 mass parts is preferable with respect to 100 mass parts of copolymers, and, as for content of the processing aid in a resin composition, 0.5-3 mass parts is more preferable.

  The acrylic resin as a processing aid is not particularly limited, and contains 50% by mass 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 mass 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 mass 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 a foam suitable for foaming. The foamability of the particles may not be improved.

As another resin, an aromatic vinyl-unsaturated dicarboxylic acid-unsaturated dicarboxylic imide copolymer 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 preferred.

  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 mass of units derived from aromatic vinyl, assuming that the total of the units derived from 3 is 100 parts by mass. It is preferable that 2-30 mass parts of units derived from unsaturated dicarboxylic acid and 20-80 mass parts of units derived from unsaturated dicarboxylic imide are included.
When the proportion of units derived from aromatic vinyl is less than 20 parts by mass, 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 be degraded. When this ratio is larger than 80 parts by mass, the heat resistance of the foamed molded product may be lowered. This ratio is more preferably 30 to 75 parts by mass, and still more preferably 50 to 70 parts by mass.

(4) Additive The base resin may contain an additive in addition to the resin as 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, perfumes, phases. Examples of the additives include modifiers and modifiers.
(5) Manufacturing method A resin composition can be manufactured by melt-kneading each main component which comprises it, for example.

(Foamed particles)
The expanded particles are composed of a plurality of bubbles and a bubble wall that partitions the bubbles. The cell walls are derived from the aromatic vinyl resin composition for producing the expanded particles.
The average particle diameter of the expanded particles is preferably 500 to 5000 μm, and more preferably 1000 to 3000 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 0.8 or more (the upper limit is a true sphere).

The expanded particles preferably have a bulk multiple of 1.4 to 20 times. If the bulk multiple is less than 1.4 times, the foamed particles have non-uniform bubbles, and the foamability of the foamed particles during foam molding may be insufficient. When the ratio is larger than 20 times, the open cell ratio of the expanded particles increases, and the expandability of the expanded particles may decrease during expansion molding. The bulk multiple is more preferably 1.6 to 14 times, and particularly preferably 2 to 12.5 times.
The expanded particles preferably exhibit an open cell ratio of 40% or less. When the open cell ratio is higher than 40%, the foaming pressure of the foamed particles is insufficient at the time of foam molding, and the heat fusion integration between the foamed particles is insufficient, and the mechanical properties of the foam molded article may be deteriorated. . The open cell ratio is more preferably 35% or less.

The expanded particles can be produced, for example, by a method in which resin particles are impregnated with a foaming agent in a gas phase to obtain expandable particles, and the expandable particles are expanded.
First, as a method for producing resin particles,
(I) Manufactured by melting and kneading raw material resin (mixture of constituent resins of base resin) in an extruder, cooling the kneaded product (resin composition) while extruding it from a nozzle mold attached to the extruder. how to,
(Ii) A method in which a raw material resin is melt-kneaded in an extruder, the kneaded product is extruded from a nozzle mold attached to the extruder, cooled to obtain a strand, and the strand is cut at predetermined intervals. ,
(Iii) A method in which a raw material resin is melt-kneaded in an extruder, the kneaded product is extruded from an annular die or a T-die attached to the extruder to produce a sheet, and the sheet is cut to produce the method. 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 mass parts is preferable with respect to 100 mass parts of resin compositions. When the amount of the bubble adjusting agent is less than 0.01 parts by mass, the bubbles of the expanded particles become coarse, and the appearance of the obtained foamed molded product may be deteriorated. When the amount is more than 5 parts by mass, the closed cell ratio of the expanded particles may decrease due to bubble breakage. As for the quantity of a bubble regulator, 0.05-3 mass parts is more preferable, and 0.1-2 mass parts is especially preferable.

  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 these, dimethyl ether, propane, normal butane, isobutane and carbon dioxide are preferable, propane, normal butane and isobutane are more preferable, and normal butane and isobutane 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, 0.1-5 mass parts is preferable with respect to 100 mass parts of raw material resin, 0.2-4 mass parts is more preferable, and, as for the amount of foaming agents, 0.3-3 mass parts is especially preferable.
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.

The expanded particles are cooled after being cut while supplying the copolymer and polylactic acid into the extruder, melting and kneading them in the presence of a physical foaming agent, and extruding the extrudate from a nozzle mold attached to the extruder. Can also be manufactured. Note that the melt kneading of the copolymer and polylactic acid may be performed in advance in another extruder before being performed in the presence of the physical foaming agent. An example of a manufacturing apparatus that can be used in this method will be described with reference to FIGS.
Here, FIG. 3 shows a state in which foamed particles containing a foaming agent are produced using an extruder and a nozzle mold 1 attached to the front end thereof.
As shown in FIG. 4, a plurality of nozzle outlet portions 11 are formed on the same virtual circle A at equal intervals on the front end surface 10 of the nozzle mold 1.
At the portion surrounded by the nozzle outlet 11 on the front end face 10 of the nozzle mold 1, the rotating shaft 2 is disposed in a state of protruding forward. The rotary shaft 2 is connected to a drive 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 are integrally provided on the outer peripheral surface of the rear end portion of the rotary shaft 2. All the rotary blades 5 are always in contact with the front end face 10 of the nozzle mold 1 during the rotation.
When a plurality of rotary blades 5 are integrally provided on the rotary shaft 2, the plurality of rotary blades 5 are arranged at equal intervals in the circumferential direction of the rotary shaft 2.

FIG. 4 shows a case where four rotary blades 5 are integrally provided on the outer peripheral surface of the rotary shaft 2 as an example.
When the rotary shaft 2 rotates, the rotary blade 5 moves on the virtual circle A in which the nozzle outlet portion 11 is formed while constantly contacting the front end surface 10 of the nozzle mold 1, and the nozzle outlet The foamed extrudate extruded from the portion 11 is configured to be capable of being sequentially and continuously cut.
A cooling member 4 is disposed so as to surround at least the front end portion 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 to draw a shape.

The coolant 42 gradually spreads in the direction orthogonal to the traveling direction while traveling along the inner peripheral surface of the peripheral wall portion 41b. As a result, the inner peripheral surface of the peripheral wall portion 41 b in front of the supply port 41 c of the cooling drum 41 is completely covered with the cooling liquid 42.
The coolant 42 is not particularly limited as long as the foamed particles can be cooled, and examples thereof include water and alcohol. Of these, water is preferable in view of the treatment after use.
As a temperature of a cooling fluid, 5-40 degreeC is preferable. When it is less than 5 ° C., the mold temperature is remarkably lowered, and extrusion may become unstable. When the temperature is higher than 40 ° C., the foamed particles are insufficiently cooled, the open cell ratio is increased, and the foaming power at the time of compounding may be reduced. In addition, the non-foamed or high-density skin on the surface of the foamed particles becomes thin, and the foaming power at the time of compositing may be reduced. The temperature of the cooling liquid is more preferably 8 to 30 ° C, particularly preferably 10 to 35 ° C.

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 expanded particles and the coolant 42 can be continuously discharged through the discharge port 41e.
Foam extrusion obtained by supplying a copolymer and polylactic acid to an extruder, melt-kneading in the presence of a foaming agent, and then extruding and extruding the extrudate from a nozzle mold 1 attached to the front end of the extruder. The foamed particles can be produced by cutting the object with the rotary blade 5.

(Foamed molded product)
The foamed molded product preferably has a multiple of 1.4 to 20 times. When the multiple is smaller than 1.4 times, the advantage of foaming may be reduced because the mass increases. If it is larger than 20 times, the mechanical properties may be insufficient. The multiple is more preferably 1.6 to 14 times, and particularly preferably 2 to 12.5 times.
The foamed molded product preferably exhibits an open cell ratio of 40% or less. When the open cell ratio is higher than 40%, the mechanical properties of the foamed molded product may be deteriorated. The open cell ratio is more preferably 35% or less.

  As a method for producing a foamed molded article, the foam particles are filled in a cavity of a mold, a heating medium is supplied into the cavity, the foam particles are heated to be re-foamed, and the foam particles that have been re-foamed are made up of these. There is a method of obtaining a foamed molded article by heat fusion and integration with each other by the foaming pressure. Examples of the heating medium include water vapor, hot air, hot water and the like, and water vapor is preferable.

(Use)
The foamed molded article is excellent in lightness, heat resistance and mechanical properties (particularly brittleness). 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.

(Complex)
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.
In particular, when the synthetic resin impregnated into the reinforcing fibers is an epoxy resin, the resin composition has the following effects. That is, since the copolymer is soluble in the epoxy resin, the foamed molded product is dissolved during the production of the fiber reinforced composite, and the fusion between the foamed molded product and the fiber reinforced plastic layer may be insufficient. . However, when the resin composition contains polylactic acid, solubility in the epoxy resin can be suppressed, and as a result, the fusing property between the foamed molded product and the fiber-reinforced plastic layer can be improved.
The content of the synthetic resin in the fiber reinforced plastic is preferably 20 to 70% by mass. When the oil content is less than 20% by mass, the binding property between the reinforcing fibers and the adhesive property 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 mass, the mechanical properties of the fiber reinforced plastic may deteriorate, and the mechanical strength of the fiber reinforced composite may not be sufficiently improved. As for content, 30-60 mass% is more preferable.

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 in a high temperature environment, the above method (4) can also be suitably used.

  Examples of the method used for molding the fiber reinforced plastic include an autoclave method, a hand lay-up 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.

(Bending elastic modulus of resin composition)
The flexural modulus of the resin composition was measured by the method described in JIS K7171: 2008 “Plastics-Determination of bending properties”. In other words, using the “Tensilon UCT-10T” universal testing machine manufactured by Orientec Co., Ltd. and the “UTPS-458X” universal testing machine data processing software manufactured by SoftBrain Co., Ltd., the test piece size is 10 mm wide × 80 mm long × 4 mm thick. The compression speed was 2 m / min, the pressure wedge 5R, and the support base 5R were measured at a fulcrum distance of 64 mm. The number of test pieces was a minimum of five. The flexural modulus was obtained using the origin of displacement as the regression point. The test piece was previously annealed at 100 ° C. for 5 hours. The flexural modulus E (MPa) was calculated by the following formula.
E = αL ³ / (4bd ³ )
α: Elastic modulus gradient (N / mm)
L: Distance between fulcrums (mm)
b: Width of test piece (mm)
d: Test piece thickness (mm)

(Melting tension of resin composition)
The melt tension of the resin composition was measured using a twin-bore capillary-rheometer-Rheological 5000T (manufactured by Chiast, Italy). The sample was previously vacuum-dried at 100 ° C. for 4 hours and then sealed and stored until immediately before measurement. After filling the sample resin in a 15 mm diameter barrel heated to a test temperature of 200 ° C. and preheating for 5 minutes, the capillary die of the above measuring device (caliber 2.095 mm, length 8 mm, inflow angle 90 degrees (conical)) While the piston descending speed (0.07730 mm / s) is kept constant and extruded into a string shape, the string-like material is passed through a tension detection pulley located 27 cm below the capillary die, and then a winding roll The winding speed is gradually increased at an initial speed of 4 mm / s and an acceleration of 12.0 mm / s ² , and the maximum and minimum values of the tension just before the point at which the string-like object is cut are taken. Was the melt tension of the sample resin.

(Flexural modulus of foamed molded product)
The flexural modulus of the foamed molded product was measured by a method in accordance with JIS K7222-1: 2006 “Hard 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 foam molded article. A Tensilon universal testing machine ("UCT-10T" manufactured by Orientec Co., Ltd.) was used for the measurement. The flexural modulus was calculated using universal testing machine data processing software (“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 (%)

(Heat dimensional change rate of molded foam)
The heating dimensional change rate of the foamed molded article was measured by the method B described in JIS K6767: 1999 “Foamed Plastics-Polyethylene Test Method”. Specifically, a test piece having a square shape with a planar shape of 150 mm on a side and a thickness of the foam molded body was cut out from the foam molded body.
Three 100 mm straight lines were written at 50 mm intervals in the center of the test piece in parallel to each other in the vertical and horizontal directions. The lengths of three straight lines in each of the vertical and horizontal directions were measured, and the arithmetic average value L ₀ was taken as the initial dimension. Thereafter, the test piece was left in a 120 ° C. hot air circulating drier for 168 hours to conduct a heating test and then taken out, and the test piece was left at 25 ° C. for 1 hour. Next, the length of each of three straight lines in the vertical and horizontal directions written on the surface of the test piece was measured, and the arithmetic average value L ₁ was taken as the dimension after heating. The heating dimensional change rate was calculated based on the following formula.
Heating dimensional change rate (%) = 100 × (L ₁ −L ₀ ) / L ₀

(Bulk density and bulk multiple)
The bulk density was measured according to JIS K6911: 1995 “General Test Method for Thermosetting Plastics”. That is, it measured using the apparent density measuring device based on this JIS, and measured the bulk density based on the following formula.
Bulk density of expanded particles (g / cm ³ ) = [mass cylinder in which sample was put (g) −mass cylinder mass (g)] / [volume of graduated cylinder (cm ³ )]
The bulk multiple was obtained by adding the resin density to the reciprocal of the bulk density.

(Density and multiple)
Measure the mass (a) and volume (b) of the test piece cut out from the foamed molded product (example 75 × 300 × 30 mm) so that it is 3 digits or more of significant figures respectively, and foam according to the formula (a) / (b) The density (g / cm ³ ) of the compact was determined.
The multiple was a value obtained by adding the density of the resin to the reciprocal of the density.

(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.
・ 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 are 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 was an 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 the baseline, were mean maximum absorbance between 1810 cm ^-1 and 1745 cm ^-1.

Further, the absorbance D1720 at 1720 cm ⁻¹ was the absorbance corresponding to the absorption spectrum derived from the antisymmetric stretching vibration caused by the carbonyl group C═O contained in methyl methacrylate.
In this absorbance measurement, peak separation was not performed even when other absorption spectra overlapped at 1720 cm ⁻¹ . Absorbance D1720 is a straight line connecting the 1920Cm ^-1 and 1620 cm ^-1 as the baseline, were mean maximum absorbance between 1745 cm ^-1 and 1690 cm ^-1.

Absorbance D698 at 698 cm ⁻¹ was the absorbance corresponding to the absorption spectrum derived from the out-of-plane bending vibration of C—H in the monosubstituted benzene ring in styrene.
In this absorbance measurement, peak separation was not performed even when other absorption spectra overlapped at 698 cm ⁻¹ . Absorbance D698 is a straight line connecting the 1510 cm ^-1 and 810 cm ^-1 as a baseline had mean 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 mass 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 mass of 2,2′-azobis (2,4-dimethylvaleronitrile) was added to 100 parts by mass of the monomer to dissolve the monomer. The obtained mixed solution was 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) 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 (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.

Standard samples of styrene resin and maleic anhydride resin include 1/1 copolymer of styrene and maleic anhydride (trade name SMA1000 (P) manufactured by CRAY VALLEY) and 3/1 of styrene and maleic anhydride. A polymer (SMA3000 (P) 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

(Example 1-Example of resin particle production)
Styrene-methyl methacrylate-maleic anhydride copolymer (trade name “DENKA RESISFY R-200”, manufactured by Denki Kagaku Kogyo Co., Ltd., styrene: 53 parts by mass, methyl methacrylate: 30 parts by mass, maleic anhydride: 17 parts by mass , Density 1.16 g / cm ³ ) and polylactic acid (trade name “TERRAMAC TP-4000”, manufactured by Unitika Ltd.) at a ratio shown in Table 1 and fed to a twin screw extruder having a diameter of 30 mm at 240 ° C. Melt kneaded. In Table 1, SMM means styrene-methyl methacrylate-maleic anhydride copolymer, and PLA means polylactic acid. Subsequently, a kneaded product (resin composition) is extruded from each nozzle of a multi-nozzle mold (12 nozzles having a diameter of 1.0 mm arranged in a circle) attached to the front end of the twin-screw extruder. did. The extruded kneaded material was immediately cooled in a cooling water bath. The cooled strand kneaded product 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 1.2 to 1.6 mm and a particle diameter D of 1.0 to 1.2 mm.
The bending elastic modulus and melt tension of the obtained resin particles were measured. The measurement results are shown in Table 1. In addition, when 90 mass parts and 100 mass parts of PLA were used, since the pelletizer was not able to cut | disconnect with a small particle, a bending elastic modulus and melt tension were not able to be measured.

The results for the flexural modulus and the melt tension in Table 1 are plotted in FIGS. 1 and 2, respectively. 1 and 2 show an approximate curve of a plot and a straight line connecting two plots of PLA of 0% by mass and 80% by mass.
FIG. 1 regarding the flexural modulus shows that when PLA is greater than 0% by mass and less than 80% by mass, a plot of the flexural modulus is located above the straight line. The inventor believes that the position of this plot is caused by partial cross-linking of SMM and PLA. Specifically, since the PLA amount is small on the left side of FIG. 1 and the SMM amount is small on the right side, the SMM and PLA are not sufficiently cross-linked. As a result, the effect of improving the flexural modulus is low. On the other hand, when the PLA amount is around 50% by mass, the SMM and the PLA are sufficiently cross-linked. As a result, the effect of improving the flexural modulus is high. In addition, the expression of the approximate curve obtained from a plurality of plots of the flexural modulus in FIG. 1 is Y (flexural modulus) = − 0.0902X (PLA amount) ² + 8.9288X + 3521.6.
In FIG. 2 regarding the melt tension, the approximate curve shows an inflection point in the vicinity of the PLA amount of 30% by mass. This inflection point can suppress a decrease in melt tension due to cross-linking when polylactic acid is added. The inventor believes that this is caused by a decrease. In addition, the inventor believes that the resin particles in the vicinity of the inflection point give the foamed molded product obtained therefrom an effect of improving physical properties by crosslinking. In addition, the equation of the approximate curve obtained from the plurality of plots of the melt tension in FIG. 2 is Y (melt tension) = − 0.0002X (PLA amount) ³ + 0.0172X ² −0.7743X + 42.122.

(Example 2-Production example of foam molded article)
(Foaming process)
The foamed particles were produced using the production apparatus shown in FIGS. Styrene-methyl methacrylate-maleic anhydride copolymer (trade name “DENKA RESISFY R-200”, manufactured by Denki Kagaku Kogyo Co., Ltd., styrene: 53 parts by mass, methyl methacrylate: 30 parts by mass, maleic anhydride: 17 parts by mass , Density 1.16 g / cm ³ ) 80 parts by mass, 20 parts by mass of polylactic acid (trade name “TERRAMAC TP-4000”, manufactured by Unitika Ltd.) and a modifier (trade name “Tuftec MP10”, manufactured by Asahi Kasei) A resin composition containing 5 parts by mass and 0.4 parts by mass of talc is supplied to a tandem type extruder having a diameter of 50 mm and a second extruder having a diameter of 65 mm connected to the end of the first extruder 250 Melt-kneaded at a temperature of 0 °

  Subsequently, from the middle of the extruder, butane composed of 35% by mass of isobutane and 65% by mass of normal butane was pressed into the molten resin composition so as to be 0.9 parts by mass with respect to 100 parts by mass of the resin composition. And uniformly dispersed in the resin composition.

  Then, after the molten resin composition was cooled to 185 ° C. at the front end of the extruder, the resin composition was extruded and foamed from each nozzle of the multi-nozzle mold 1 attached to the front end of the extruder. The extrusion rate of the resin composition was 30 kg / hour.

  The multi-nozzle mold 1 has 20 nozzles having an outlet portion 11 having a diameter of 1 mm, and all the outlet portions 11 of the nozzle have a diameter of 139, which is assumed on the front end face 1a of the multi-nozzle die 1. It was arranged on a virtual circle A of 5 mm at regular intervals.

  Then, 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. It was comprised so that it might move on the virtual circle A in the state which always contacted the front-end surface 1a of the metal mold | die 1. FIG.

Further, the cooling member 4 includes a cooling drum 41 including 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. It was. The cooling water 42 at 20 ° C. was supplied into the cooling drum 41 through the supply pipe 41 d and the supply port 41 c of the cooling drum 41. The volume in the cooling drum 41 was 17684 cm ³ .

  The cooling water 42 draws a spiral along the inner peripheral surface of the peripheral wall portion 41b of the cooling drum 41 due to 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. The cooling liquid 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 supply port 41c of the cooling drum 41 The inner peripheral surface of the more peripheral wall portion 41b was entirely covered with the coolant 42.

  And the rotary blade 5 arrange | positioned in the front end surface 1a of the multi-nozzle metal mold | die 1 is rotated at the rotation speed of 3400 rpm, and the resin extrudate extruded and foamed from the exit part 11 of each nozzle of the multi-nozzle metal mold | die 1 is used. Cutting with the rotary blade 5 produced substantially spherical expanded particles. The resin extrudate consisted of an unfoamed portion immediately after being extruded from the nozzle of the multi-nozzle mold 1 and a foaming portion in the course of foaming that continued to the unfoamed portion. And the resin extrudate was cut | disconnected in the opening end of the exit part 11 of a nozzle, and the cutting | disconnection of the resin extrudate was performed in the unfoamed part.

  In manufacturing the above-mentioned expanded particles, 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 resin extrudate is extruded and foamed from the extruder, and the resin extrudate immediately after being extruded from the nozzle of the multi-nozzle mold 1 and the foaming portion in the process of foaming continuous to the unfoamed portion. It was confirmed that Next, after attaching the rotary shaft 2 to the multi-nozzle mold 1 and disposing the cooling member 4 at a predetermined position, the rotary shaft 2 is rotated, and the resin extrudate is rotated at the opening end 11 of the nozzle at the rotary end 5. The expanded particles were cut by cutting.

  The foamed particles are blown outward or forward by the cutting stress of the rotary blade 5, and the upstream side of the flow of the cooling water 42 flows into the cooling water 42 flowing along the inner surface of the cooling drum 41 of the cooling member 4. The foam particles collided with the surface of the cooling water 42 so as to follow the cooling water 42 from the downstream side to the downstream side, and the foamed particles entered the cooling water 42 and immediately cooled.

  The cooled foamed 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 bulk density and bulk multiple of the obtained foamed particles were measured by the above-described method. The bulk density was 0.16 g / cm ³ and the bulk multiple was 7 times.

(Molding process)
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 30 mm in height is formed between the male and male molds.

  Foam particles were filled into the mold cavity of the in-mold foam molding machine, and the mold was clamped. Thereafter, 120 ° C. water vapor with a gauge pressure of 0.10 MPa is supplied from the male mold side into the mold cavity for 5 seconds, and then the gauge pressure is 0.10 MPa from the female mold side into the mold cavity. Of 120 ° C. was supplied over 3 seconds. After that, 134 ° C. water vapor with a gauge pressure of 0.20 MPa is supplied from both sides of the male and female molds into the mold cavity for 20 seconds, and the foamed particles are heated and subjected to secondary foaming. The secondary foamed particles obtained by secondary foaming were heat-sealed and integrated with each other by these foaming pressures to obtain a rectangular parallelepiped foam molded body having a length of 300 mm, a width of 400 mm, and a height of 30 mm.

  Next, cooling water was supplied into the mold cavity to cool the foam molded article, and then the cavity was opened to obtain a foam molded article.

  The obtained foamed molded article had a flexural modulus of 61 MPa and a heating dimensional change rate of -0.16%.

DESCRIPTION OF SYMBOLS 1 Nozzle metal mold, 2 Rotating shaft, 3 Drive member, 4 Cooling member, 5 Rotary blade, 10 Front end surface, 11 Outlet part, 41 Cooling drum, 41a Front part, 41b Perimeter wall part, 41c Supply port, 41d Supply pipe, 41e Discharge port, 41f Discharge pipe, 42 Coolant (cooling water), A Virtual circle

Claims (10)

  An aromatic vinyl resin composition for producing expanded particles, wherein the aromatic vinyl resin composition is a copolymer of aromatic vinyl, (meth) acrylic acid ester, and unsaturated dicarboxylic acid, An aromatic vinyl-based resin composition for producing expanded particles, comprising a base resin to which polylactic acid is added.   The aromatic vinyl resin composition for producing expanded particles according to claim 1, wherein the copolymer and polylactic acid are contained in the base resin at a ratio of 95: 5 to 55:45 (mass%).   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 aliphatic unsaturated dicarboxylic acid, and the copolymer is 100 parts by mass of the total of units derived from the aromatic vinyl, (meth) acrylic acid ester and unsaturated dicarboxylic acid, 30 to 80 parts by mass of units derived from the aromatic vinyl, 8 to 35 parts by mass of units derived from the (meth) acrylic acid ester, and 10 to 50 parts by mass of units derived from the unsaturated dicarboxylic acid The aromatic vinyl resin composition for producing expanded particles according to claim 1 or 2. The polylactic acid in the aromatic vinyl resin composition is
Measure the flexural modulus when the polylactic acid content is 0% by mass and 80% by mass, and connect the two obtained points with a straight line.
When the content ratio of polylactic acid is an arbitrary value on the straight line, the bending elastic modulus of the aromatic vinyl resin composition is included so as to be 50 MPa or more higher than that on the straight line. An aromatic vinyl-based resin composition for producing expanded particles according to any one of the above. The polylactic acid in the aromatic vinyl resin composition is
Measure the melt tension in various cases where the polylactic acid content ratio is between 0% and 80% by mass, and draw an approximated curve by degree 3 polynomial approximation in the graph from the various measured values obtained. Define inflection points,
The aromatic vinyl-based resin composition for producing expanded particles according to any one of claims 1 to 4, which is included in a range of 10% by mass before and after the content ratio of polylactic acid corresponding to the inflection point. .   The aromatic vinyl resin composition for producing foamed particles according to any one of claims 1 to 5, wherein the foamed wall is composed of a plurality of bubbles and a cell wall partitioning the cells. Expanded particles characterized by being derived from a product.   A foam-molded product obtained by foam-molding the foamed particles according to claim 6.   A fiber-reinforced composite comprising the foam-molded body according to claim 7 and a fiber-reinforced plastic layer laminated and integrated on the surface of the foam-molded body.   The fiber-reinforced composite according to claim 8, which is used for wind turbine blades, robot arms, and automobile parts.   The automotive part comprised from the foaming molding of Claim 8, or the fiber reinforced composite_body | complex of Claim 9.

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