JP2013064128A - Method for producing foam molded article, resin material, foam article, heat-insulating member, and fluid retention member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a foam molded article that includes a resin having a high working temperature and in which the supercritical fluid is used as a foaming agent.SOLUTION: The present invention relates to a method for producing the foam molded article, the method comprising: melting and kneading together a resin material containing an aromatic polysulfone having a reduced viscosity of 0.35 to 0.55 dL/g, and a foaming agent comprising the supercritical fluid of a substance that is a gas at room temperature and atmospheric pressure and does not react with the aromatic polysulfone in a supercritical state; and thereafter molding while foaming the same by lowering at least one of pressure and temperature of the foaming agent.

Description

  The present invention relates to a method for producing a foam molded article, a resin material, a foam, a heat insulating member, and a fluid holding member.

  Conventionally, since plastic is lighter than metal, it has been widely used in various application fields such as electric and electronic parts, automobile parts, and miscellaneous goods. Further, as demands for further weight reduction of plastics increase, a technique using a chemical foaming agent and a technique of foaming a resin by heating or the like are known as a technique for reducing the specific gravity of a resin product.

  In recent years, for the purpose of improving mechanical properties and surface roughness in addition to weight reduction, a foam molding technique using a supercritical fluid as a foaming agent has been disclosed (for example, see Patent Documents 1 to 3).

Japanese Patent Laid-Open No. 10-175249 JP 2002-168279 A Japanese Patent No. 4191510

  However, when foam molding using a chemical foaming agent is applied to a resin material including a resin material having a high processing temperature, various problems are likely to occur due to insufficient heat resistance of the foaming agent. For example, when the foaming agent is excessively decomposed, the resin is decomposed and the molecular weight is lowered, resulting in coloring of the molded product, enlargement of foamed cells and poor foaming, poor appearance, generation of odor during processing, Various problems such as contamination of the molding die due to adhesion of the resin decomposition product and drooling due to low viscosity of the resin may occur.

  In addition, when a supercritical fluid is used as the foaming agent, the problem in the case of using the chemical foaming agent as described above hardly occurs. However, in Patent Documents 1 to 3, a resin material having a relatively low processing temperature is used. Only the application examples are disclosed, and the resin material having a high processing temperature is not sufficiently mentioned.

  This invention is made | formed in view of such a situation, Comprising: It aims at providing the manufacturing method of the foaming molding using the resin material with high processing temperature. Moreover, providing the resin material which can be used suitably for such a manufacturing method, providing the foam obtained using such a resin material, and the heat insulation member which has such a foam It is another object to provide a fluid holding member.

  In order to solve the above problems, one embodiment of the present invention is a resin material containing an aromatic polysulfone having a reduced viscosity of 0.35 dL / g or more and 0.55 dL / g or less, and the aromatic polysulfone in a supercritical state. After melt-kneading a non-reactive foaming agent composed of a supercritical fluid of a gaseous substance at ordinary temperature and pressure, at least one of the pressure and temperature of the foaming agent is lowered to below the critical point of the foaming agent. Provided is a method for producing a foamed molded article that is molded while being foamed.

  Here, the “supercritical fluid” is a state of a substance under conditions of temperature and pressure (critical point) or more determined by the kind of the substance. A supercritical fluid exhibits intermediate properties between a gas state and a liquid state, has a stronger penetration force (melting power) into the molten resin than the liquid state, and can be uniformly dispersed in the molten resin.

  In one aspect of the present invention, the resin material is a foam core material that is dispersed without being dissolved in the aromatic polysulfone heated and melted in a total of 100 parts by mass of the aromatic polysulfone and the foam core material. On the other hand, it is desirable to include more than 0 parts by mass and 40 parts by mass or less.

  In one aspect of the present invention, it is desirable that the foam core material contains glass fibers.

  In one aspect of the present invention, it is desirable that the foam core material contains titanium oxide.

  In one embodiment of the present invention, the gas is preferably nitrogen.

  In one aspect of the present invention, it is desirable that the molding is injection molding.

  In one embodiment of the present invention, it is desirable to mold a molded body having a thickness of 1.5 mm to 10 mm.

  The resin material of one embodiment of the present invention is used for foam molding using a supercritical fluid of a gaseous substance at normal temperature and pressure as a foaming agent, and a reduced viscosity is 0.35 dL / g or more and 0.55 dL / g or less. An aromatic polysulfone.

  In one aspect of the present invention, the foam core material dispersed without dissolving in the aromatic polysulfone heated and melted is 0 part by mass with respect to 100 parts by mass of the sum of the aromatic polysulfone and the foam core material. It is desirable to contain more than 40 parts by mass.

  In one aspect of the present invention, it is desirable that the foam core material contains glass fibers.

  In one aspect of the present invention, it is desirable that the foam core material contains titanium oxide.

  The foam of one embodiment of the present invention is a foam made of the above-described resin material and a supercritical fluid that is non-reactive with the aromatic polysulfone contained in the resin material in a supercritical state and is a gaseous substance at normal temperature and pressure. It is obtained by melt-kneading and foaming the agent.

  In one embodiment of the present invention, the gas is preferably nitrogen.

  In one embodiment of the present invention, it is preferable to have a portion with a thickness of 1.5 mm to 10 mm.

  Moreover, the heat insulation member of 1 aspect of this invention has the above-mentioned foam.

  The fluid holding member of one embodiment of the present invention includes the above-described foam.

  According to the present invention, a reduced viscosity of an aromatic polysulfone to be used is controlled within a predetermined range, and a supercritical fluid is used as a foaming agent. Can be provided. Moreover, the resin material which can be used suitably for such a manufacturing method can be provided. Furthermore, it becomes possible to provide a favorable foam by using such a resin material. And by having such a foam, it is possible to provide a fluid holding member such as a fuel tank that has high heat resistance and is lightweight, and a heat insulating member.

It is a schematic diagram of the injection molding machine used for manufacture of the foaming molding of this embodiment.

  A method for producing a foamed molded product according to an embodiment of the present invention includes a resin material containing an aromatic polysulfone having a reduced viscosity of 0.35 dL / g or more and 0.55 dL / g or less, and the aromatic polysulfone in a supercritical state. After melt-kneading a non-reactive foaming agent composed of a supercritical fluid of a gaseous substance at ordinary temperature and pressure, at least one of the pressure and temperature of the foaming agent is lowered to below the critical point of the foaming agent. Molding while foaming.

The resin material which concerns on embodiment of this invention is used suitably for the above-mentioned manufacturing method, and contains the aromatic polysulfone whose reduced viscosity is 0.35 dL / g or more and 0.55 dL / g or less.
The resin material may be the aromatic polysulfone alone or a resin composition containing the aromatic polysulfone and other components.

  A foam according to an embodiment of the present invention is a foaming agent comprising the above-described resin material and a supercritical fluid that is a non-reacting material with an aromatic polysulfone contained in the resin material in a supercritical state and is a gas substance at normal temperature and pressure. And kneading and foaming.

The heat insulating member and the fluid holding member according to the embodiment of the present invention have the above-described foam.
In this specification, a heat insulation member is a member used as a partition which physically divides two substances which have a temperature difference, for example, a member used when one substance is high temperature of 80 ° C or more. .
Further, in this specification, the fluid holding member is a member for passing or holding a fluid such as liquid or gas inside. For example, there can be mentioned automobile parts such as pipes through which fluid is communicated, fuel tanks, battery parts, oil peripheral parts, and the like. Hereinafter, it demonstrates in order.

(Aromatic polysulfone)
The aromatic polysulfone used in this embodiment is typically a divalent aromatic group (residue obtained by removing two hydrogen atoms bonded to the aromatic ring from an aromatic compound) and a sulfonyl group (-SO _2- ) and a resin having a repeating unit containing an oxygen atom. The aromatic polysulfone preferably has a repeating unit represented by the following formula (1) (hereinafter sometimes referred to as “repeating unit (1)”) from the viewpoint of heat resistance and chemical resistance, A repeating unit represented by the following formula (2) (hereinafter sometimes referred to as “repeating unit (2)”) or a repeating unit represented by the following formula (3) (hereinafter referred to as “repeating unit (3)”). It may have one or more other repeating units.

(1) -Ph ¹ -SO ₂ -Ph ² -O-
(Ph ¹ and Ph ² each independently represent a phenylene group. The hydrogen atoms in the phenylene group may each independently be substituted with an alkyl group, an aryl group, or a halogen atom.)

^{(2) -Ph 3 -R-Ph} 4 -O-
(Ph ³ and Ph ⁴ each independently represents a phenylene group. The hydrogen atoms in the phenylene group may each independently be substituted with an alkyl group, an aryl group, or a halogen atom. R represents an alkylidene. Represents a group, oxygen atom or sulfur atom.)

_{^{(3) - (Ph 5)}} n -O-
(Ph ⁵ represents a phenylene group. The hydrogen atoms in the phenylene group may be each independently substituted with an alkyl group, an aryl group or a halogen atom. N represents an integer of 1 to 3. When n is 2 or more, a plurality of Ph ⁵ may be the same or different from each other.)

The phenylene group represented by any of Ph ^{1 to} Ph ⁵ may be a p-phenylene group, an m-phenylene group, or an o-phenylene group. -A phenylene group is preferred.

  In the alkyl group which may substitute the hydrogen atom in the phenylene group, the number of carbon atoms is preferably 1-10. Specific examples include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-hexyl group, 2-ethylhexyl group, n-octyl group. Group and n-decyl group.

  In the aryl group which may substitute for the hydrogen atom in the phenylene group, the number of carbon atoms is preferably 6-20. Specific examples include phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, 1-naphthyl group and 2-naphthyl group.

  When the hydrogen atom in the phenylene group is substituted with these groups, the number is preferably 2 or less and more preferably 1 or less for each phenylene group.

  In the alkylidene group represented by R, the number of carbon atoms is preferably 1-5. Specific examples include a methylene group, an ethylidene group, an isopropylidene group, and a 1-butylidene group.

  The aromatic polysulfone preferably has 50% by mole or more, more preferably 80% by mole or more of the repeating unit (1) with respect to the total of all the repeating units. It is more preferable to have only). In addition, aromatic polysulfone may have 2 or more types of repeating units (1)-(3) each independently.

  The aromatic polysulfone can be produced by polycondensation of a dihalogenosulfone compound and a dihydroxy compound corresponding to the repeating unit constituting the aromatic polysulfone.

  For example, a resin having a repeating unit (1) uses a compound represented by the following formula (4) as a dihalogenosulfone compound (hereinafter sometimes referred to as “compound (4)”), and a dihydroxy compound represented by the following formula: It can manufacture by using the compound represented by (5).

  Further, a resin having the repeating unit (1) and the repeating unit (2) is produced by using the compound represented by the following formula (6) as the dihydroxy compound using the compound (4) as the dihalogenosulfone compound. can do.

  Further, a resin having the repeating unit (1) and the repeating unit (3) is produced by using the compound represented by the following formula (7) as the dihydroxy compound using the compound (4) as the dihalogenosulfone compound. can do.

_{^{(4) X 1 -Ph 1 -SO}} 2 -Ph 2 -X 2
(X ¹ and X ² each independently represent a halogen atom. Ph ¹ and Ph ² are as defined above.)

(5) HO—Ph ¹ —SO ₂ —Ph ² —OH
(Ph ¹ and Ph ² are as defined above.)

^{(6) HO-Ph 3 -R} -Ph 4 -OH
(Ph ³ , Ph ⁴ and R are as defined above.)

(7) HO— (Ph ⁵ ) _n —OH
(Ph ⁵ and n are as defined above.)

  The polycondensation of the aromatic polysulfone is preferably performed in a solvent using an alkali metal carbonate. The alkali metal salt of carbonic acid may be a carbonate that is a normal salt, a bicarbonate (hydrogen carbonate) that is an acidic salt, or a mixture of both. As the carbonate, sodium carbonate and potassium carbonate are preferably used, and as the bicarbonate, sodium bicarbonate and potassium bicarbonate are preferably used.

  As the polycondensation solvent, an organic polar solvent is preferably used. Specific examples include dimethyl sulfoxide, 1-methyl-2-pyrrolidone, sulfolane (1,1-dioxothyrane), 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, dimethyl Examples include sulfone, diethyl sulfone, diisopropyl sulfone, and diphenyl sulfone.

  The aromatic polysulfone used in the present embodiment has a reduced viscosity of 0.35 dL / g or more and 0.55 dL / g or less. The higher the reduced viscosity, the easier it is to improve the heat resistance, strength, and rigidity. However, if the reduced viscosity exceeds 0.55 dL / g, the amount of foaming becomes insufficient or the flowability of the molten resin decreases. The processability at the time of manufacturing a molded body is insufficient. On the other hand, when the reduced viscosity is less than 0.35 dL / g, decomposition of the resin is likely to proceed during processing, and problems such as not reaching the strength required as a molded article and discoloration due to insufficient heat resistance are likely to occur.

  The reduced viscosity of the aromatic polysulfone can be controlled, for example, by changing the reaction conditions when performing polycondensation.

  In the polycondensation, if no side reaction occurs, (1) the molar ratio of the dihalogenosulfone compound as the reaction substrate to the dihydroxy compound is close to 1: 1, and (2) the amount of alkali metal salt of carbonic acid used. The more the reaction conditions are (3) higher polycondensation temperature and (4) longer polycondensation time, the higher the degree of polymerization of the resulting aromatic polysulfone and the higher the reduced viscosity. However, in fact, side reaction such as substitution reaction of halogeno group to hydroxy group or depolymerization occurs due to by-produced alkali hydroxide (alkali metal hydroxide), and the resulting aromatic polysulfone is obtained by this side reaction. The degree of polymerization tends to decrease, and the reduced viscosity tends to decrease.

  Therefore, when the aromatic polysulfone is polymerized by polycondensation, the molar ratio of the dihalogenosulfone compound and the dihydroxy compound so that an aromatic polysulfone having a desired reduced viscosity is obtained in consideration of the degree of this side reaction, It is preferable to adjust the amount of alkali metal carbonate used, the polycondensation temperature and the polycondensation time.

  The reduced viscosity of the aromatic polysulfone may be prepared by mixing two or more aromatic polysulfones having different reduced viscosities obtained under different polycondensation reaction conditions. For example, an aromatic polysulfone having a reduced viscosity of 0.30 dL / g that is lower than the lower limit of the above range and an aromatic polysulfone having a reduced viscosity of 0.60 dL / g that exceeds the upper limit of the above range may be, for example, 1 : 1 can be prepared so as to be an aromatic polysulfone having a reduced viscosity in the above-mentioned range as a whole.

(Foam core material)
In the resin material of the present embodiment, the foam core material dispersed without being dissolved in the aromatic polysulfone heated and melted is 0 mass relative to 100 parts by mass of the sum of the aromatic polysulfone and the foam core material. It is good also as containing 40 mass parts or less more than a part.

  Here, the foam core material in the present specification is a compounding material that becomes a base point (core) in which the above-mentioned supercritical fluid melted and kneaded becomes a gas in the aromatic polysulfone heated and melted, and is heated and melted. It has the property of dispersing without dissolving in the aromatic polysulfone.

  When the resin material contains the foamed core material, vaporization of the supercritical fluid is promoted at innumerable locations in the molten resin, and a foam in which foam cells are well dispersed can be obtained. Further, at the time of molding, a foamed cell oriented in the flow direction of the molten resin is formed, so that a streak-like appearance defect called a silver streak may occur, but the resin material contains a foam core material. Therefore, the effect of disturbing the orientation of the foam cells and suppressing the silver stripes can also be expected. In addition, improvement in strength and rigidity (elastic modulus) can be expected.

  The foam core material contained in the resin material may be a fibrous filler, a plate-like filler, or a spherical or other granular filler other than a fibrous or plate-like material. Also good. The filler may be an inorganic filler or an organic filler.

  Examples of fibrous inorganic fillers include glass fibers; carbon fibers such as pan-based carbon fibers and pitch-based carbon fibers; ceramic fibers such as silica fibers, alumina fibers and silica-alumina fibers; and metal fibers such as stainless steel fibers. It is done. In addition, whiskers such as potassium titanate whisker, barium titanate whisker, wollastonite whisker, aluminum borate whisker, silicon nitride whisker, and silicon carbide whisker are also included.

  Examples of fibrous organic fillers include polyester fibers and aramid fibers.

  Examples of the plate-like inorganic filler include talc, mica, graphite, wollastonite, glass flake, barium sulfate, and calcium carbonate. Mica may be muscovite, phlogopite, fluorine phlogopite, or tetrasilicon mica.

  Examples of the particulate inorganic filler include silica, alumina, titanium oxide, glass beads, glass balloons, boron nitride, silicon carbide and calcium carbonate.

  The content of these foamed core materials is preferably 0 to 40 parts by mass with respect to 100 parts by mass of the aromatic polysulfone.

  As the foam core material, it is preferable to use glass fiber because it functions as a reinforcing material for the molded body and is available at low cost. Moreover, it is also preferable to use a titanium oxide from the point that whitening of a molded object is possible, and you may use glass fiber and a titanium oxide together.

  As the glass fiber applicable to the resin material of the present embodiment as the foam core material, the molten glass was processed into a fiber shape through a die having a desired fiber diameter, and then cut to an appropriate length. The thing (chopped strand) can be mentioned. Further, the present invention is not limited thereto, and glass fibers having various fiber diameters and fiber lengths can be used as long as the object of the present invention is not impaired.

  The fiber length of the glass fiber is preferably 1 mm or more and 10 mm or less, and more preferably 1 mm or more and 8 mm or less because of easy handling. Moreover, it is preferable that the single fiber diameter of glass fiber is 5 micrometers or more and 25 micrometers or less.

  Such a glass fiber may use a sizing agent for improving the adhesion to the aromatic polysulfone and facilitating the handling of the glass fiber when spinning. As such a sizing agent, for example, a surface treatment agent such as a silane coupling agent, a titanium coupling agent, and a thermosetting resin typified by an epoxy resin can be used.

  The blending ratio of the aromatic polysulfone and the glass fiber is such that the glass fiber is more than 0 parts by weight and less than 40 parts by weight, preferably more than 0 parts by weight and more than 30 parts by weight with respect to 100 parts by weight as the total of the aromatic polysulfone and the glass fibers. It is as follows. When there are many glass fibers with respect to aromatic polysulfone, a shaping | molding process will become difficult.

  The titanium oxide applicable to the resin material of the present embodiment as the foam core material may have a rutile type, anatase type, or a mixture of both. Since it is easy to obtain a molded article having high reflectance and excellent weather resistance, those containing rutile type titanium oxide are preferable, and those substantially consisting only of rutile type titanium oxide are more preferable.

  The method for producing titanium oxide may be a chlorine method or a sulfuric acid method, but the chlorine method is preferred when producing a rutile type titanium oxide. When producing titanium oxide by the chlorine method, first, ore (synthetic rutile ore obtained from rutile or ilmenite ore), which is a titanium source, and chlorine are reacted at around 1000 ° C. to obtain crude titanium tetrachloride. It is preferable that titanium tetrachloride is purified by rectification and then oxidized with oxygen.

  The particle size of titanium oxide is expected to be highly dispersible in the resin, and the resulting molded product is expected to be whitened efficiently. It is 2 μm or less, more preferably 0.1 μm or more and 1 μm or less, further preferably 0.15 μm or more and 0.5 μm or less, and particularly preferably 0.2 μm or more and 0.4 μm or less.

  The volume average particle size referred to here is obtained by photographing a white pigment with a scanning electron microscope (SEM), and using the obtained SEM photograph with an image analyzer ("Luzex IIIU" manufactured by Nireco Corporation). This is the particle size when the cumulative degree is 50% in the distribution curve obtained by analyzing to obtain the area equivalent diameter of each particle and accumulating them on the volume basis.

  The titanium oxide may be subjected to a surface treatment. For example, dispersibility can be improved by performing a surface treatment using an inorganic metal oxide. As the inorganic metal oxide, aluminum oxide (alumina) is preferably used. In view of heat resistance and strength, it is preferable to use titanium oxide that has not been surface-treated.

  The blending ratio of the aromatic polysulfone and the titanium oxide is such that the total amount of the aromatic polysulfone and the titanium oxide is 100 parts by mass, the titanium oxide is more than 0 parts by mass and not more than 40 parts by mass, preferably more than 0 parts by mass and 30 parts by mass. It is as follows. When there is much titanium oxide with respect to aromatic polysulfone, a shaping | molding process may become difficult and intensity | strength may fall.

(Other ingredients)
Furthermore, the resin material of the present embodiment may contain one or more other components such as additives and resins other than aromatic polysulfone, in addition to the above-described aromatic polysulfone and foamed core material.

  Examples of the additive include heat stabilizers such as phosphorus compounds, phenol compounds, and sulfur compounds. These heat stabilizers have a total amount of aromatic polysulfone and foam core material of 100 parts by mass, and 0.01 parts by mass or more and 1 part by mass with respect to 100 parts by mass of aromatic polysulfone and foam core material. When added below, coloring during granulation or molding can be suppressed.

  Additives other than heat stabilizers, for example, release agents such as fluororesins and metal soaps, pigments such as titanium oxide, colorants such as dyes, antioxidants, heat stabilizers, ultraviolet absorbers, antistatic agents A surfactant or the like may be added as a component. The content of these additives is preferably 0.01 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the aromatic polysulfone.

  Examples of resins other than aromatic polysulfone include thermoplastic resins other than aromatic polysulfone such as polypropylene, polyamide, polyester, polyphenylene sulfide, polyether ketone, polycarbonate, polyphenylene ether, and polyetherimide; and phenol resins, epoxy resins, Thermosetting resins such as polyimide resin and cyanate resin are listed. The content of the resin other than aromatic polysulfone is preferably 0 to 20 parts by mass with respect to 100 parts by mass of aromatic polysulfone.

  The resin material of the present embodiment is preferably melt-kneaded using an extruder and pelletized in order to facilitate handling during the production of the foam described below. When the resin material contains a foam core material, the foam core material can be uniformly dispersed in the resin material by melt-kneading in advance.

  As the extruder, one having a cylinder, one or more screws arranged in the cylinder, and one or more supply ports provided in the cylinder is preferably used, and further one place provided in the cylinder. What has the above vent part is used more preferably.

(Foam)
The foam of this embodiment can be obtained by melting and kneading the above-described resin material with a supercritical fluid and foaming. In the present embodiment, the obtained foam may be subsequently molded (secondary processing), or may be molded simultaneously with foaming to obtain a foamed molded product. Since a molded body can be obtained with high productivity, it is preferable to obtain a foamed molded body by molding simultaneously with foaming.
In addition, the heat insulation member and fluid holding member in this invention have the said foam. When forming simultaneously with foaming and obtaining a heat insulation member and a fluid holding member, these heat insulation members and a fluid holding member correspond to the above-mentioned foaming fabrication object.

(Supercritical fluid)
The foaming agent used in the present embodiment is composed of a supercritical fluid that is non-reactive with the above-described aromatic polysulfone in a supercritical state and is a gas substance at normal temperature and pressure.

  Here, the “supercritical fluid” is a term indicating a state of a substance that is neither a gas, a liquid nor a solid, which is exhibited by the substance under conditions of a specific temperature and pressure (critical point) or higher. The critical point, which is a specific temperature and pressure, is determined by the type of material. A supercritical fluid exhibits intermediate properties between a gas state and a liquid state, has a stronger penetration force (melting power) into the molten resin than the liquid state, and can be uniformly dispersed in the molten resin.

  In the present embodiment, as the supercritical fluid, for example, an inert gas such as carbon dioxide, nitrogen, or helium, air, oxygen, hydrogen, or the like can be used as the fluid, but carbon dioxide or nitrogen is more preferable. Furthermore, since nitrogen has a critical point of temperature: −147 ° C. and pressure: 3.4 MPa and is above the critical temperature at room temperature (25 ° C.), it is possible to prepare a supercritical fluid only by controlling the pressure. Therefore, it is easy to handle and is particularly preferable.

(Production method)
When the above-mentioned resin material is foamed and simultaneously molded to obtain a foamed molded product, a melt molding method is used as a method for producing the foamed molded product. Examples of the melt molding method include an injection molding method, an extrusion molding method such as a T-die method and an inflation method, a blow molding method, a vacuum molding method and a press molding. Of these, the extrusion molding method and the injection molding method are preferable, and the injection molding method is more preferable. Hereinafter, a method for producing a foamed molded article by injection molding will be described.

FIG. 1 is a schematic view of an injection molding machine used for producing the foamed molded product of the present embodiment.
The injection molding machine 1 is a machine for producing a foam molded body having a predetermined shape using the above-described resin material and supercritical fluid, and introduces a main body 11, a mold 12, and a supercritical fluid into the main body 11. And a supercritical fluid introducing device 21 for the purpose.

  The introduction device 21 includes a gas cylinder 211 filled with the above-described supercritical fluid source gas, a booster 212 that boosts the source gas from the gas cylinder 211 to a critical pressure, and a source gas (supercritical pressure) that has been boosted to a critical pressure. And a control valve 213 for controlling the amount of fluid introduced into the cylinder 111. The source gas is heated by adiabatically compressing the source gas in the booster 212, but if the reached temperature is less than the critical temperature, the source gas from the gas cylinder 211 is heated to the critical temperature as necessary. Use a heater.

Next, the manufacturing method of the foam using this injection molding machine 1 is demonstrated.
First, the above-described resin material is charged into the cylinder 111 from the hopper 113 and heated and kneaded in the cylinder 111 to melt the resin material. On the other hand, the gas cylinder 211 is opened, and the pressure of the source gas is raised to a critical point or higher by the booster 212 and the temperature is raised. The obtained supercritical fluid is introduced into the cylinder 111 by opening the control valve 213 and impregnated into the molten resin material.

  Next, the molten resin containing the supercritical fluid in the cylinder 111 is moved by the screw 112 and injected into the mold 12. At this time, until the injection of the molten resin into the mold 12 is completed, the mold 12 is clamped and counter pressure is applied to maintain the supercritical state of the supercritical fluid contained in the molten resin. May be.

  In the mold 12, since the temperature and pressure of the supercritical fluid decrease simultaneously with the cooling of the molten resin, the raw material gas changes from the supercritical state to the gaseous state. Therefore, the molten resin is foamed into a foam. Furthermore, after the resin in the mold 12 is cooled and solidified, the molded product is taken out from the mold 12 after a predetermined cooling time has elapsed. By the above operation, a foamed molded article by injection molding can be obtained.

  In the method for producing a foamed molded product according to this embodiment, a thin foamed molded product having a thickness of 1.5 mm to 10 mm can be suitably produced.

  Examples of products and parts that are foam molded articles of the present embodiment include bobbins such as optical pickup bobbins and transformer bobbins; relay parts such as relay cases, relay bases, relay sprues, and relay armatures; RIMM, DDR, and CPU sockets. , S / O, DIMM, Board to Board connector, FPC connector, card connector, etc .; Lamp reflector, LED reflector, etc .; Lamp holder, heater holder, etc .; Speaker diaphragm, etc. Separation claws, separation claws for printers, etc .; Camera module parts; Switch parts; Motor parts; Sensor parts; Hard disk drive parts; Tableware such as ovenware; Vehicle parts; Aircraft parts; Sealing members such as a sealing member for use.

Moreover, since the foaming molding which concerns on this embodiment is excellent in heat resistance and heat insulation, it can be conveniently used as a fluid holding member for passing or holding a high temperature liquid inside. Examples of such fluid holding members include automobile parts such as tanks, battery parts, and oil peripheral parts.
Moreover, since the foaming molding which concerns on this embodiment is excellent in heat resistance and heat insulation, it can be used conveniently also as a heat insulation member. As such a heat insulating member, for example, a member having a function of suppressing (insulating) heat from a member having a high temperature of 80 ° C. or higher to another member such as an engine cover can be exemplified.

  According to the manufacturing method as described above, the reduced viscosity of the aromatic polysulfone to be used is controlled within a predetermined range and a supercritical fluid is used as a foaming agent, so that a foam molded article using a resin material having a high processing temperature easily. The manufacturing method of can be provided.

  Moreover, the above resin materials can be used suitably for such a manufacturing method. Furthermore, by using such a resin material, it becomes possible to provide a good foam. By having such a foam, a fluid holding member and a heat insulating member having high heat resistance and reduced weight are provided. can do.

  EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

(Measurement of reduced viscosity of aromatic polysulfone)
About 1 g of aromatic polysulfone was dissolved in N, N-dimethylformamide to make the volume 1 dL, and the viscosity (η) of this solution was measured at 25 ° C. using an Ostwald type viscosity tube. Further, the viscosity (η ₀ ) of N, N-dimethylformamide as a solvent was measured at 25 ° C. using an Ostwald type viscosity tube. From the viscosity (η) of the solution and the viscosity (η ₀ ) of the solvent, a specific viscosity ((η−η ₀ ) / η ₀ ) is obtained, and this specific viscosity is determined by the concentration of the solution (about 1 g / dL ) To obtain the reduced viscosity (dL / g) of the aromatic polysulfone.

(Measurement of specific gravity of foam molding)
The specific gravity was calculated by measuring the dimensions and mass of the obtained foamed molded article.

(Observation of silver strips on foamed molded products)
By observing the appearance of the obtained foamed molded article, the presence or absence of silver stripes on the surface was determined.

(Measurement of flexural strength and flexural modulus of foamed molded product)
A test piece having a width of 13 mm, a length of 125 mm, and a thickness of 3 mm was cut out from the obtained foamed molded article, and the test piece was spanned using an A & D universal tester “Tensilon RTG-1250”. The measurement was performed by carrying out a three-point bending test under the measurement conditions of a distance of 50 mm and a test speed of 1 mm / min.

(Measurement of thermal conductivity of foam molding)
A test piece having a width of 60 mm, a length of 60 mm, and a thickness of 3 mm was cut out from the obtained foamed molded product, and the test piece was subjected to a heating current using a rapid thermal conductivity meter “QTM-500” manufactured by Kyoto Electronics Industry Co., Ltd. It measured on the measurement conditions of 2.00.

<Production Example 1>
In a polymerization tank equipped with a stirrer, a nitrogen introduction tube, a thermometer, and a condenser with a receiver at the tip, 500 g of bis (4-hydroxyphenyl) sulfone, 598 g of bis (4-chlorophenyl) sulfone, and diphenyl as a polymerization solvent 957 g of sulfone was charged, and the temperature was raised to 180 ° C. while flowing nitrogen gas through the system. After adding 287 g of potassium carbonate to the obtained solution, the temperature was gradually raised to 290 ° C., and the mixture was further reacted at 290 ° C. for 2 hours. The obtained reaction solution was cooled to room temperature, solidified, finely pulverized, washed with warm water and washed with a mixed solvent of acetone and methanol several times, then heated and dried at 150 ° C., and the terminal was a chloro group. An aromatic polysulfone (hereinafter referred to as aromatic polysulfone A) was obtained as a powder. As a result of measuring the reduced viscosity of the aromatic polysulfone A, it was 0.36 dL / g.

<Production Example 2>
In the same manner as in Production Example 1, except that 500 g of bis (4-hydroxyphenyl) sulfone, 589 g of bis (4-chlorophenyl) sulfone, and 942 g of diphenylsulfone as a polymerization solvent were added to the polymerization tank, the terminal was a chloro group. A certain aromatic polysulfone (hereinafter referred to as aromatic polysulfone B) was obtained as a powder. As a result of measuring the reduced viscosity of this aromatic polysulfone B, it was 0.59 dL / g.

<Example 1>
After adding 0.2 parts by mass of triphenyl phosphate (manufactured by Wako Pure Chemical Industries, Ltd.) as a heat stabilizer to 100 parts by mass of the aromatic polysulfone A powder, a twin screw extruder made by Ikegai Co., Ltd. Pellets made of a resin material for foam molding were produced by melt kneading using “PCM-30”. As melt kneading conditions at this time, the cylinder set temperature of this twin-screw extruder was 330 ° C., and the screw rotation speed was 150 rpm. Cylinder set temperature here means the average value of the set temperature of the heating apparatus provided from the most downstream part of the cylinder to about 2/3 of the cylinder length.

  The pellets produced by the above-described method are all electric molding machine “J450AD” manufactured by Nippon Steel Works, Ltd., and TREXEL. Using a supercritical fluid production unit “SCF SYSTEM” manufactured by Inc., supercritical nitrogen is introduced when a resin is heated and measured in a cylinder at a set temperature of 360 ° C. and injected into a mold at a set temperature of 120 ° C. As a result, a foamed molded article having a flat plate shape (250 mm × 360 mm × 3 mmt) was formed.

<Example 2>
Example 1 except that 80 parts by weight of aromatic polysulfone A powder and 20 parts by weight of glass fiber “CS03JAPx-1” manufactured by Owens Corning Japan Co., Ltd. were mixed to obtain 100 parts by weight. Similarly, a foamed molded product was produced.

<Example 3>
97 parts by mass of the aromatic polysulfone A powder and 3 parts by mass of titanium oxide “TIPAQUE CR-60” manufactured by Ishihara Sangyo Co., Ltd. were mixed to obtain 100 parts by mass in the same manner as in Example 1. A foamed molded product was produced.

<Comparative Example 1>
A molded body was produced in the same manner as in Example 1 except that the supercritical nitrogen was not introduced and the molded body was produced by ordinary injection molding.

<Comparative example 2>
A molded body was produced in the same manner as in Example 2 except that the supercritical nitrogen was not introduced and a molded body was produced by ordinary injection molding.

<Comparative Example 3>
A molded body was produced in the same manner as in Example 3 except that the supercritical nitrogen was not introduced and the molded body was produced by ordinary injection molding.

<Comparative example 4>
An attempt was made to produce a molded body in the same manner as in Example 1 except that the aromatic polysulfone B powder was used, the cylinder setting temperature of the twin screw extruder was 360 ° C., and the cylinder temperature of the molding machine was 400 ° C. Since the flowability of the molten resin was low and a necessary amount could not be injected into the mold, a molded product as designed could not be obtained.

  For Examples 1 to 3 and Comparative Examples 1 to 4, molding conditions, specific gravity, bending strength, bending elastic modulus, thermal conductivity, and presence or absence of silver strips are shown in Table 1 below.

  As is clear from the comparison between the examples and the comparative examples, when the aromatic polysulfone having the reduced viscosity defined in the present invention is used, the foam molding can be performed satisfactorily using a supercritical fluid. Was found to be obtained. In the foamed molded bodies in Examples 1 to 3, the specific gravity is lower than that of the molded body of the comparative example, and weight reduction by foaming can be realized. In addition, a reduction in thermal conductivity, that is, thermal insulation is realized.

  Further, according to Example 2, it was found that even when 20 parts by mass of glass fiber was added as a foam core material, foam molding was possible and a foam molded article was obtained. Furthermore, from the comparison between Example 1 and Example 2, by adding glass fiber as the foam core material, the molded body of Example 2 becomes a molded body having superior strength and rigidity than the molded body of Example 1, Furthermore, it turned out that the surface silver strip lose | disappears and it becomes a molded object which exhibits a favorable external appearance.

  Further, according to Example 3, it was found that even when 3 parts by mass of titanium oxide was added as a foam core material, foam molding was possible and a foam molded article was obtained. Further, from the comparison between Example 1 and Example 3, by adding titanium oxide as a foam core material, the molded body of Example 3 becomes a molded body having the same strength and rigidity as the molded body of Example 1. Furthermore, it was found that the silver strip on the surface disappeared and a molded body having a good appearance was obtained.

  From these results, the usefulness of the present invention was confirmed.

  DESCRIPTION OF SYMBOLS 1 ... Injection molding machine, 11 ... Main body, 12 ... Mold, 21 ... Introduction apparatus, 211 ... Gas cylinder, 212 ... Booster, 213 ... Control valve,

Claims (16)

  A resin material containing an aromatic polysulfone having a reduced viscosity of 0.35 dL / g or more and 0.55 dL / g or less, and a supercritical fluid which is non-reactive with the aromatic polysulfone in a supercritical state and is a gas substance at normal temperature and pressure And a foaming agent comprising: a foamed molded article formed by molding while foaming by lowering at least one of the pressure and temperature of the foaming agent below a critical point of the foaming agent.   More than 0 parts by mass of the resin material, with respect to 100 parts by mass of the sum of the aromatic polysulfone and the foamed core material, the foamed core material dispersed without being dissolved in the aromatic polysulfone heated and melted The manufacturing method of the foaming molding of Claim 1 containing 40 mass parts or less.   The manufacturing method of the foaming molding of Claim 2 in which the said foaming core material contains glass fiber.   The manufacturing method of the foaming molding of Claim 2 or 3 in which the said foaming core material contains a titanium oxide.   The method for producing a foam molded article according to any one of claims 1 to 4, wherein the gas is nitrogen.   The method for producing a foam molded article according to any one of claims 1 to 5, wherein the molding is injection molding.   The manufacturing method of the foaming molding of any one of Claim 1 to 6 which shape | molds the molded object which has a part whose thickness is 1.5 mm or more and 10 mm or less.   A resin material containing an aromatic polysulfone having a reduced viscosity of 0.35 dL / g or more and 0.55 dL / g or less, which is used for foam molding using a supercritical fluid of a gaseous substance at normal temperature and pressure as a foaming agent.   A foam core material that is dispersed without dissolving in the aromatic polysulfone heated and melted is contained in an amount of more than 0 parts by mass and less than 40 parts by mass with respect to 100 parts by mass of the sum of the aromatic polysulfone and the foam core material. Item 9. The resin material according to Item 8.   The resin material according to claim 9, wherein the foam core material includes glass fibers.   The resin material according to claim 9 or 10, wherein the foam core material includes titanium oxide.   A foaming agent comprising the resin material according to any one of claims 8 to 11 and a supercritical fluid that is non-reactive with the aromatic polysulfone contained in the resin material in a supercritical state and is a gaseous substance at normal temperature and pressure. And a foam obtained by melt-kneading and foaming.   The foam according to claim 12, wherein the gas is nitrogen.   The foam of Claim 12 or 13 which has a part whose thickness is 1.5 mm or more and 10 mm or less.   The heat insulation member which has a foam of any one of Claim 12 to 14.   The fluid holding member which has a foam of any one of Claim 12 to 14.

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