JP2021006622A - Foam molding and method for producing the same - Google Patents

Abstract

To provide a foam molding of a thermoplastic resin material using a foaming agent of water-soluble alkali silicate, and to obtain a foam molding which secures a large number of air bubble parts by the production method.SOLUTION: There are provided a foam molding that forms a foaming agent 1 by treating water-soluble alkali silicate having a predetermined molar ratio with a predetermined water content, preferably, forms a particulate foaming agent 1 having a particle size of 500 μm or less by treating sodium silicate aqueous solution having a molar ratio of 2-3.2 with a water content of 5-30 wt.%, covers a large number of air bubble parts 1A with a film 2A of a thermoplastic resin material 2 molten by foaming the foaming agent 1 by heating the foaming agent 1 at a temperature equal to or higher than the melting temperature of the thermoplastic resin material 2 in a state of being brought into contact with the thermoplastic material 2, and connects the large number of air bubble parts 1A; and a method for producing the same.SELECTED DRAWING: Figure 1

Description

The present invention relates to a foamed molded product of a thermoplastic resin material using a foaming agent formed by treating a water-soluble alkaline silicate.

Various foamed molded articles of thermoplastic resin materials using a foaming agent of a water-soluble alkaline silicate such as water glass have been proposed.

According to Patent Document 1, M2O: SiO2: H2O = 21-85: 100: 3 ~ A foamable composition (alkali anhydride silicate) represented by 150 (where M is an alkali metal) is obtained from polyethylene, polypropylene, polytetrafluorinated ethylene, polyvinyl chloride, polystyrene, ABS resin, polymethacrylic acid ester, polycarbonate, polyamide, and the like. It is mixed with a thermoplastic resin such as saturated polypropylene, and the mixture is released at about 80 ° C. to generate water vapor, and the pressure of the water vapor causes small bubbles to expand and connect with each other to form bubbles. A method for producing a foam in which a thermoplastic resin film is formed around bubbles that have become open cells by breaking the diaphragm due to the pressure difference inside has been proposed.

However, in the foam of the thermoplastic resin of Patent Document 1, although the foaming composition is dried by specifying the weight ratio in terms of alkali oxide, silicic anhydride and water, it is water-soluble with a predetermined molar ratio. It is not disclosed that the alkaline silicate is treated so as to have a predetermined water content, and the foaming agent is heated above the melting temperature of the thermoplastic resin material in a state where the foaming agent is in contact with the thermoplastic resin material. It is not disclosed that the surface of a large number of bubble portions melted by foaming is coated and the large number of bubble portions are connected to each other.

Further, as a foamed molded product in which the foaming agent is added to the synthetic resin using a mixed foaming agent of water glass and borosand, 120 g of borosand is added to 1000 cc of trichloroethylene and stirred to dissolve it in Patent Document 2. Based on microencapsulation that forms a unified white granule of about 5 mmφ by stirring while dropping 100 g of water glass (No. 2), the foaming agent is set to 100 and the urethane resin synthetic resin is set to 100. It is disclosed that a foamed molded product formed into a plate by heating at a rate is obtained.

However, although a foamed molded product in which the foaming agent is added to the synthetic resin by using the mixed foaming agent of water glass and borosand of Patent Document 2, it is water-soluble with a predetermined molar ratio as in Patent Document 1. The alkali silicate is treated to have a predetermined water content to form a foaming agent, and the surface of a large number of bubble portions is covered with a film of a molten thermoplastic resin material, and the spaces between the large number of bubble portions are covered. It is not disclosed to obtain a foamed molded product formed by connecting them.

Special Publication No. 41-16705 Special Publication No. 55-10557

In the present invention, in order to solve the above problems, a large number of bubble portions are secured by a foam molded body of a thermoplastic resin material using a foaming agent formed by treating a water-soluble alkaline silicate and a method for producing the same. The purpose is to obtain a foamed molded product thus produced.

The foamed molded product according to claim 1 of the present invention contains a water-soluble alkali silicate represented by the general formula M2O · nSiO2 (where M represents an alkali metal of sodium or potassium and n represents a molar ratio). In a foamed molded product formed by foaming the foaming agent formed by the treatment at the melting temperature of the thermoplastic resin material in a state of being in contact with the thermoplastic resin material, a water-soluble alkali silicate having a predetermined molar ratio is specified. The foaming agent is formed by processing so as to have a water content, and the foaming agent is foamed and melted by heating above the melting temperature of the thermoplastic resin material in a state where the foaming agent is in contact with the thermoplastic resin material. It is characterized in that the surface of a large number of bubble portions is covered with a coating of a plastic resin material and the large number of bubble portions are connected to each other. In claim 1, the foamed molded product according to claim 2 is water-soluble in the sodium silicate aqueous solution having a predetermined molar ratio, such as a boron compound such as borax and boric acid, magnesium hydroxide, calcium hydroxide, and aluminum hydroxide. It is characterized in that a foaming agent is formed by treating one or a combination of two or more metal compounds so as to have a predetermined water content. The foamed molded product according to claim 3 uses an aqueous sodium silicate solution having a molar ratio of 2 to 3.2 as the water-soluble alkali silicate having a predetermined molar ratio in claims 1 or 2, and has a weight of 5 to 30. A large number of particulate foaming agents are formed by treating the mixture so as to have a water content of%, and the particulate foaming agent is foamed at the melting temperature of the thermoplastic resin material to form a melted film of the thermoplastic resin material. It is characterized in that it is formed by covering the surface of the bubble portion of the above and connecting the large number of the bubble portions. In any one of claims 1 to 3, the foamed molded article according to claim 4 is a particulate foaming agent having a particle size of 500 μm or less, and the thermoplastic resin material. Is a super engineering plastic. The method for producing a foamed molded product according to claim 5 is a water-soluble alkaline silicate represented by the general formula M2O · nSiO2 (where M represents an alkali metal of sodium or potassium and n represents a molar ratio). In the method for producing a foamed molded product in which the foaming agent formed by the above treatment is foamed at the melting temperature of the thermoplastic resin material in the presence of the thermoplastic resin material, the molar ratio of the water-soluble alkali silicate having the predetermined molar ratio is used. Using a sodium silicate aqueous solution of 2 to 3.2, the sodium silicate aqueous solution having a molar ratio of 2 to 3.2 is dried, and a sodium silicate solid having a water content of 5 to 30% by weight is crushed into particles. A foaming agent forming step of obtaining a foaming agent, a mixing step of mixing the particulate foaming agent and a thermoplastic resin material to form a mixture, and heating the mixture at a temperature equal to or higher than the melting point of the thermoplastic resin material. A heating foaming step of foaming a foaming agent to form a large number of bubble portions and forming a film of the molten thermoplastic resin material on the outer periphery of the bubble portions, and a heating foaming step of forming the molten thermoplastic resin material by cooling. It is characterized by comprising a cooling step of obtaining a foamed molded product formed by solidifying the coating film and connecting a large number of bubble portions with the coating film. The method for producing a foamed molded product according to claim 6, wherein in the foaming agent forming step, a water-soluble alkaline silicate having a molar ratio of 2 to 3.2, a boron compound such as borax or boric acid, or a boron compound is used. One or two or more water-soluble metal compounds such as magnesium hydroxide, calcium hydroxide, and aluminum hydroxide are combined, and 5 to 15% by weight of each is mixed and dissolved so as to have a water content of 5 to 30% by weight. It is characterized in that it is processed to form a particulate foaming agent.

The foamed molded product of the present invention is a foam formed by treating a water-soluble alkali silicate represented by the general formula M2O · nSiO2 (where M represents an alkali metal of sodium or potassium and n represents a molar ratio). In a foamed molded product formed by foaming the agent at the melting temperature of the thermoplastic resin material in a state of being in contact with the thermoplastic resin material, a water-soluble alkaline silicate having a predetermined molar ratio is adjusted to have a predetermined water content. The foaming agent is formed by treatment, and the foaming agent is foamed and melted by heating above the melting temperature of the thermoplastic resin material in a state where the foaming agent is in contact with the thermoplastic resin material. It is formed by covering the surface of a large number of bubble portions and connecting the large number of bubble portions, and further, boring compounds such as borosand and boric acid and magnesium hydroxide in the sodium silicate aqueous solution having a predetermined molar ratio. Bubbles (hereinafter referred to as glass) in which a glass film is formed by forming a foaming agent by treating one or more water-soluble metal compounds such as calcium hydroxide and aluminum hydroxide so as to have a predetermined water content. (Represented as a film-like balloon) remains, and by providing a method for producing the same, a large number of bubble portions can be secured, and it can be used for all thermoplastic resins including super engineering plastics.

It is sectional drawing of the foam molded article in Embodiment 1 of this invention. It is sectional drawing of the foam molded article in Embodiment 2 of this invention. It is sectional drawing of the foam molded article in Embodiment 3 of this invention. It is explanatory drawing which shows the existence state of the thermoplastic resin material around the foam molded article of this invention. It is explanatory drawing which shows the heated foaming state of the foam molded article of this invention. It is a work diagram which shows the manufacturing process of the foam molding body of this invention. It is a perspective view of the foam molded article of this invention. FIG. 5 is an enlarged view of an AA cross section of FIG. 7 in the foam molded product obtained in Example 2. FIG. 5 is an enlarged view of an AA cross section of FIG. 7 in the foam molded product obtained in Example 3.

(Effervescent action in the foam molded product of the present application)
The foaming action of the foamed molded product will be described below with reference to FIGS. 1 to 5. The foamed molded product in the present invention includes a simple substance and a composite of the foamed molded product.

In FIG. 4, the foaming agent 1 is formed by treating a water-soluble alkaline silicate having a predetermined molar ratio to a predetermined water content, and is preferably formed as a water-soluble alkaline silicate having a predetermined molar ratio. Is treated with an aqueous sodium silicate solution of 2 to 3.2 so as to have a water content of 5 to 30% by weight, preferably 15 to 20% by weight, and the particle size is 500 μm or less. It is formed in the form of particles. A thermoplastic resin material 2 is present around the foaming agent 1, and the thermoplastic resin material 2 is in contact with the foaming agent 1, preferably, the thermoplastic resin material 2 is smaller than the foaming agent 1. It is in contact with the foaming agent 1 with a solid having a large particle size or a semi-cured material containing water. In this case, in order to bring the foaming agent 1 into contact with the thermoplastic resin material 2, the foaming agent 1 and the thermoplastic resin material 2 may be mixed to form a mixture. Therefore, as a mixing method thereof, a mixer device or a spraying device is used. The foaming agent 1 and the thermoplastic resin material 2 may be mixed using the above.

Further, as the foaming agent 1, the foaming agent using a water-soluble alkaline silicate will be described below in the first, second and third embodiments, but a borax such as borax and boric acid is added to a predetermined molar ratio of an aqueous sodium silicate solution. The same applies to the foaming agent 1 in which one or more water-soluble metal compounds such as a compound, magnesium hydroxide, calcium hydroxide, and aluminum hydroxide are combined and treated so as to have a predetermined water content. To obtain a closed-cell foam molded product of the thermoplastic resin material 2 in which the film of the thermoplastic resin material 2 is strengthened so as to be poorly water-soluble or insoluble, and the poorly water-soluble or insoluble film remains. Compared to a foamed molded product made of open cells, the strength is improved, and the heat insulating property and dielectric constant are improved. In this case, a predetermined water content is obtained by combining one or more water-soluble metal compounds such as borax and boric acid and water-soluble metal compounds such as magnesium hydroxide, calcium hydroxide and aluminum hydroxide in a sodium silicate aqueous solution having a predetermined molar ratio. As the foaming agent 1 treated so as to be, preferably, an aqueous solution of sodium silicate having a molar ratio of 2 to 3.2 is used, and this aqueous solution of sodium silicate is used, and borax, boric acid, etc. are used with respect to the solid sodium silicate salt. One or two or more water-soluble metal compounds such as borax compound, magnesium hydroxide, calcium hydroxide, and aluminum hydroxide are combined, and 5 to 15% by weight of each is mixed and dissolved to obtain a water content of 5 to 30% by weight. It is processed so as to be formed into particles having a particle size of 500 μm or less.

In FIGS. 1 to 3 and 5, the thermoplastic resin material 2 is heated to a temperature equal to or higher than the melting temperature of the thermoplastic resin material 2 in a state of being in contact with the foaming agent 1, and the surface of the bubble portion 1A is melted. The coating film 2A of the resin material 2 is coated. In this case, the presence of the thermoplastic resin material 2 is obtained by using a water-soluble alkali silicate represented by the general formula M2O · nSiO2 (where M indicates an alkali metal of sodium or potassium and n indicates a molar ratio). Not only foaming at the melting temperature of the thermoplastic resin material 2 in the state, but also a large number of foaming agents 1 formed by treating a water-soluble alkaline silicate having a predetermined molar ratio to a predetermined water content. It is a foamed molded product in which a large number of bubble portions 1A are covered and a large number of bubble portions 1A are connected to each other.Preferably, rapid heating and cooling are performed by thermal control to foam and melt the thermoplastic resin material 2. A foamed molded product is obtained in which the bubble portion 1A is secured by simultaneously performing the action. In this case, as the preferable foaming agent 1, a sodium silicate aqueous solution having a molar ratio of 2 to 3.2 is used and treated so as to have a water content of 5 to 30% by weight to form particles having a particle size of 500 μm or less. It is necessary to bring the foaming agent 1 into contact with the thermoplastic resin material 2 and perform rapid heating and cooling by thermal control so that the foaming action and the melting action of the thermoplastic resin material 2 are simultaneously performed. Therefore, in this thermal control, the water content, particle size, and heat of the foaming agent 1 are determined according to the material of the thermoplastic resin material 2, in consideration of the shape of the foamed molded product to be formed and the use of the bubble portion 1A to be secured. It may be selected and carried out based on the blending ratio of the thermoplastic resin material 2 and the foaming agent 1.

Examples of the material of the thermoplastic resin material 2 to be melted include olefin resins such as polyethylene and polypropylene, polyvinyl chloride resins, ABS resins, polyamide resins, polyester resins and fluororesins, as well as polyphenylene sulfide (PPS) and polyetheretherketone. (PEEK), thermoplastic polyimide (LARC-PAI), polyamideimide, polyarylamide, polyetherimide, polyphenylene sulfone (PPSU), polymethacrylimide (PMI) and other superengineering plastics can be exemplified. Further, these materials may be a mixture of two or more kinds of materials. Carbon fiber material or glass fiber material may be mixed with these materials.

(Embodiment 1)
FIG. 1 shows the heating agent 1 formed by treating a water-soluble alkali silicate represented by the general formula M2O · nSiO2 (where M represents an alkali metal of sodium or potassium and n represents a molar ratio). The surface state of the foamed molded product formed by foaming the thermoplastic resin material 2 at the melting temperature in the presence of the plastic resin material 2 is shown.

In FIG. 1, each of a large number of bubble portions 1A is covered with a coating film 2A of a thermoplastic resin material 2, and the coating film 2A is connected to a coating film 2A around an adjacent bubble portion 1A. In this case, if the surface intersecting with the illustrated surface is also in the same state, the bubble portion 1A is composed of closed cells, and a glass-coated balloon can be exemplified as the closed cells.

(Embodiment 2)
FIG. 2 is formed by treating a water-soluble alkali silicate represented by the general formula M2O · nSiO2 (where M represents an alkali metal of sodium or potassium and n represents a molar ratio) as in the first embodiment. The surface state of the foamed molded product formed by foaming the foaming agent 1 in the presence of the thermoplastic resin material 2 at the melting temperature of the thermoplastic resin material 2 is shown.

In FIG. 2, the bubble portion 1A and the adjacent bubble portion 1A are in contact with each other, and the periphery of each is covered with a coating film 2A of the thermoplastic resin material 2, and the coating film 2A is a coating film around the adjacent bubble portion 1A. It is connected with 2A. In this case, the bubble portion 1A is composed of open cells.

(Embodiment 3)
FIG. 3 is formed by treating a water-soluble alkali silicate represented by the general formula M2O · nSiO2 (where M represents an alkali metal of sodium or potassium and n represents a molar ratio) as in the first embodiment. The surface state of the foamed molded product formed by foaming the foaming agent 1 in the presence of the thermoplastic resin material 2 at the melting temperature of the thermoplastic resin material 2 is shown.

In FIG. 3, the bubble portion 1A and the adjacent bubble portion 1A are communicated with each other by the communication portion 1B, and the periphery thereof is covered with the coating film 2A of the thermoplastic resin material 2, and the coating film 2A is the adjacent bubble portion. It is connected to the coating 2A around 1A. In this case, the bubble portion 1A is composed of open cells.

(Manufacturing method of foam molded product)
FIG. 6 shows a step of manufacturing a foamed molded article for obtaining embodiments 1 to 3 of the above-mentioned foamed molded article using an aqueous solution of sodium silicate having a molar ratio of 2 to 3.2 as a water-soluble alkaline silicate having a predetermined molar ratio. A work diagram is shown, and the manufacturing process of this foamed molded product includes a foaming agent forming step 101, a mixing step 102, a heating foaming step 103, and a cooling step 104.

In FIG. 6, in the foaming agent forming step 101, an aqueous sodium silicate having a molar ratio of 2 to 3.2 was dried by a drying device (not shown) so as to have a water content of 5 to 30% by weight. Particles made of sodium silicate particles having a molar ratio of 2.2 to 3.2, a water content of 5 to 30% by weight, a particle size of 500 μm or less, and preferably 10 to 300 μm after crushing a solid sodium silicate. Obtain the foaming agent 1 in the form. In this case, as a method for treating the foaming agent 1 into particles, a method of forming the sodium silicate solid into a plate shape and then pulverizing the sodium silicate solid with a pulverizer to form particles can be exemplified.

Further, in the foaming agent forming step 101, instead of the particulate foaming agent 1 made of the sodium silicate particles, a water-soluble alkaline silicate having a molar ratio of 2 to 3.2, borax compounds such as borax and boric acid, and boric acid compounds are used. One or two or more water-soluble metal compounds such as magnesium hydroxide, calcium hydroxide, and aluminum hydroxide are combined, and 5 to 15% by weight of each is mixed and dissolved so as to have a water content of 5 to 30% by weight. It may be treated to obtain a particulate foaming agent which becomes a glass-coated balloon.

In the mixing step 102, the particulate foaming agent 1 and the thermoplastic resin material 2 are mixed to obtain a mixture in which the thermoplastic resin material 2 is present around the foaming agent 1 as shown in FIG. Examples of the mixing method include a mixer device that mixes both and a spraying device that sprays one to the other.

In the heat foaming step 103, the mixture is heated at a temperature equal to or higher than the melting point of the thermoplastic resin material 2 by a heating device (not shown) to foam the foaming agent 1, and as shown in FIG. A bubble portion 1A is formed, and a film 2A of the molten thermoplastic resin material 2 is formed on the outer periphery of the bubble portion 1A. As the temperature above the melting point of the thermoplastic resin material 2, in the case of the PPS resin, heating at 300 ° C. for 20 minutes can be exemplified.

In the cooling step 104, after the work is performed in the heating foaming step 103, the coating 2A of the thermoplastic resin material 2 melted by the cooling treatment by a cooling device (not shown) is solidified and between a large number of bubble portions 1A. Is connected with the thermoplastic resin material 2 to obtain a foam molded product.

57 of sodium silicate having a molar ratio of 2.5 from a 61% aqueous solution of No. 3 sodium silicate having a molar ratio of 3.17 and a 53% aqueous solution of No. 1 sodium silicate having a molar ratio of 2.10 manufactured by Fuji Chemical Co., Ltd. % Aqueous solution is prepared and heat-treated at 140 ° C. to obtain a solid body of sodium silicate having a water content of 23% by weight, and the solid body is pulverized to form a foaming agent having three kinds of particle sizes. 20 g and 60 g of PPS resin MA-520 powder manufactured by DIC Co., Ltd. are mixed, heated at 300 ° C. for 20 minutes, cooled, and as shown in FIG. 7, the vertical length X is 120 mm and the horizontal length. A confirmation sample of the foamed molded product was obtained by obtaining a foamed molded product of a plate material having a Y of 120 mm and a thickness Z of 15 mm and observing the bubble portion diameter of the foamed molded product with respect to the foaming agent formed in the form of particles having three kinds of particle sizes. As a result of observing the bubble portion diameter for each particle size of the foaming agent, the results are as shown in the table below.

A 61% aqueous solution of No. 3 sodium silicate having a molar ratio of 3.17 manufactured by Fuji Chemical Co., Ltd. was prepared and heat-treated at 140 ° C. to obtain a solid body of sodium silicate having a water content of 20% by weight, and the solid body was crushed. Then, 25 g of the particulate foaming agent and 70 g of the powder of PPS resin PN-50NNAA manufactured by Toray Co., Ltd. were mixed, heated at 300 ° C. for 20 minutes, cooled, and similarly to Example 1, FIG. As shown in the above, a foamed molded product of a plate material having a vertical length X of 120 mm, a horizontal length Y of 120 mm and a thickness Z of 15 mm was obtained, and the foaming agent formed in the form of particles having three kinds of particle sizes was obtained. Observing the bubble portion diameter of the foamed molded product A confirmation sample of the foamed molded product was prepared, and the bubble portion diameter was observed for each particle size of the foaming agent. As a result, the results are as shown in the table below.

A 61% aqueous solution of No. 3 sodium silicate having a molar ratio of 3.17 manufactured by Fuji Chemical Co., Ltd. was prepared, and 12.5% by weight of borosand and 5% by weight of magnesium hydroxide were added to the aqueous solution of the sodium silicate solid. Was mixed and heat-treated at 140 ° C. to obtain a solid body of sodium silicate having a water content of 18% by weight, and the solid body was crushed to obtain 25 g of a particulate foaming agent and PPS resin PN- manufactured by Toray Co., Ltd. 70 g of 50 NNAA powder is mixed, heated at 300 ° C. for 20 minutes, cooled, and the vertical length X is as shown in FIG. 7, as in Examples 1 and 2. Obtained a foamed molded product of a plate material having a width of 120 mm, a lateral length of 120 mm and a thickness of Z of 15 mm, and observed the bubble portion diameter of the foamed molded product with respect to the foaming agent formed in the form of particles having three kinds of particle sizes. As a result of observing the bubble portion diameter for each particle size of the foaming agent by preparing a confirmation sample of the foamed molded product, the results are as shown in the table below.

FIG. 8 shows a confirmation sample of a PPS resin foam molded product composed of sodium silicate and PPS resin shown in Example 2 and obtained by a foaming agent having a particle size of 100 to 290 μm, which is 7.5 times larger than that in the AA cross section of FIG. An enlarged cross-sectional view is shown. In the enlarged cross-sectional view shown in FIG. 8, since a large number of bubble portions 1A are cut by cutting the foamed molded product of the plate material in the AA direction, the surface (for each bubble portion 1A) intersecting the cut surface ( It is cut at various positions in the thickness Z direction) and exhibits various cut shapes. In this confirmation sample, the shape of the bubble portion 1A is the embodiment of the foam molded product shown in FIGS. 1 to 3. The bubble portions 1A of the first to third embodiments are mixed, and the periphery thereof is covered with a coating film 2A of the thermoplastic resin material 2, and the coating film 2A is connected by a coating film 2A around the adjacent bubble portion 1A. I was able to confirm that.

FIG. 9 shows a confirmation sample of a PPS resin foam molded product obtained from a foaming agent having a particle size of 100 to 290 μm, which is composed of sodium silicate and PPS resin, which are a mixture of borax and magnesium hydroxide shown in Example 3. FIG. The cross-sectional view of AA cross-sectional view is shown which is enlarged 7.5 times. In the enlarged cross-sectional view shown in FIG. 9, since a large number of bubble portions 1A are cut by cutting the foamed molded product of the plate material in the AA direction, the surface (for each bubble portion 1A) intersecting the cut surface ( It is cut at various positions in the thickness Z direction) and exhibits various cut shapes. In this confirmation sample, the white circular portion corresponds to the bubble portion 1A which is a glass-coated balloon, which is compared with FIG. It is distributed substantially uniformly, and corresponding to the first embodiment shown in FIG. 1, these bubble portions 1A are composed of closed cells, and the periphery thereof is covered with a coating film 2A of the thermoplastic resin material 2. It was confirmed that the coating film 2A was connected by the coating film 2A around the adjacent bubble portion 1A.

Therefore, the confirmation samples shown in Examples 1 and 2 were prepared, the aqueous sodium silicate solution having a molar ratio of 2 to 3.2 was dried, and the sodium silicate solid having a water content of 5 to 30% by weight was pulverized. Foam molding in which the bubble portion 1A was secured in the confirmation samples of Examples 1 and 2 by heating and foaming a particulate foaming agent having a particle size of 500 μm or less, preferably 10 to 300 μm, together with PPS resin powder at 300 ° C. I was able to prove that I could get a body. Further, the confirmation sample shown in Example 3 is prepared, and a water-soluble alkaline silicate having a molar ratio of 2 to 3.2 is mixed with a boron compound such as borax and boric acid, magnesium hydroxide, calcium hydroxide, aluminum hydroxide and the like. One or two or more water-soluble metal compounds are combined, each of which is mixed in an amount of 5 to 15% by weight and dissolved to obtain a water content of 5 to 30% by weight, and the particle size is 500 μm or less, preferably 10 to 10. It was proved that by heating and foaming a 300 μm particulate foaming agent together with a PPS resin powder at 300 ° C., a foamed molded product in which the bubble portion 1A of the glass-coated balloon was secured was obtained in the confirmation sample of Example 3. did it.

In this way, a foamed molded product that secures a large number of bubble portions can be obtained by the method for producing a foamed molded product of a thermoplastic resin material using the foaming agent of the water-soluble alkaline silicate of the present invention, but the molar ratio is high. One or two or more water-soluble alkaline silicates of 2-3.2 are combined with one or more water-soluble alkali compounds such as borosand and boric acid and water-soluble metal compounds such as magnesium hydroxide, calcium hydroxide and aluminum hydroxide. When a particulate foaming agent prepared by mixing and dissolving 15% by weight and treating the mixture so as to have a water content of 5 to 30% by weight is used, in the foaming agent forming step 101, the particulate foaming agent and thermoplasticity are used. When the mixture with the resin material is heated at a temperature equal to or higher than the melting point of the thermoplastic resin material for a predetermined time, the temperature is a constant temperature (in Example 3, 300 ° C. for 20 minutes), but there are two steps (Example). In No. 3, the temperature may be controlled at 285 ° C. for 10 minutes and at 300 ° C. for 10 minutes). Alternatively, foam molding may be performed by delaying the foaming of the glass-coated balloon formed by heating while pressurizing.

The present invention comprises a foamed molded product composed of a single body or a composite, and is useful as a cushioning material, a heat insulating material, a sound absorbing material, a filtering material or an electric insulating material, and in particular, a foaming agent of sodium silicate in the presence of a super engineering plastic. By effectively utilizing the above to provide foamed molded products using super engineering plastics, it is possible to contribute to weight reduction of automobiles, airplanes, conveyors, etc. and take part in energy saving measures.

1 Foaming agent 1A Bubble part 2 Thermoplastic resin material 2A Coating 101 Foaming agent forming step 102 Mixing step 103 Heating foaming step 104 Cooling step

Claims (6)

A foaming agent formed by treating a water-soluble alkali silicate represented by the general formula M2O · nSiO2 (where M represents an alkali metal of sodium or potassium and n represents a molar ratio) is brought into contact with a thermoplastic resin material. In a foamed molded product formed by foaming the thermoplastic resin material at the melting temperature of the thermoplastic resin material in the state of being made, a foaming agent is formed by treating a water-soluble alkali silicate having a predetermined molar ratio so as to have a predetermined water content. In a state where the foaming agent is in contact with the thermoplastic resin material, the surface of a large number of bubble portions is covered with a film of the thermoplastic resin material which is melted by foaming the foaming agent by heating above the melting temperature of the thermoplastic resin material. A foamed molded product characterized in that it is formed by coating and connecting a large number of bubble portions. A predetermined water content is obtained by combining one or more of a boron compound such as borax and boric acid and a water-soluble metal compound such as magnesium hydroxide, calcium hydroxide and aluminum hydroxide with the sodium silicate aqueous solution having a predetermined molar ratio. The foamed molded product according to claim 1, wherein the foaming agent is formed by the treatment as described above. As the water-soluble alkali silicate having a predetermined molar ratio, an aqueous sodium silicate solution having a molar ratio of 2 to 3.2 was used and treated so as to have a water content of 5 to 30% by weight to form a particulate foaming agent. , The particulate foaming agent is foamed at the melting temperature of the thermoplastic resin material, and the surface of a large number of bubble portions is covered with a film of the molten thermoplastic resin material, and the large number of bubble portions are connected to each other. The foamed molded product according to claim 1 or 2, wherein the foamed molded product is made. The one according to any one of claims 1 to 3, wherein the particulate foaming agent is a particulate foaming agent having a particle size of 500 μm or less, and the thermoplastic resin material is a super engineering plastic. Foam molded product. Presence of thermoplastic resin material as a foaming agent formed by treating a water-soluble alkali silicate represented by the general formula M2O · nSiO2 (where M represents an alkali metal of sodium or potassium and n represents a molar ratio) In the method for producing a foamed molded product in which the thermoplastic resin material is foamed at the melting temperature in the state, an aqueous sodium silicate having a molar ratio of 2 to 3.2 is used as the water-soluble alkaline silicate having a predetermined molar ratio, and the molar ratio is described. A foaming agent forming step of drying an aqueous solution of sodium silicate having a ratio of 2 to 3.2 to obtain a particulate foaming agent by pulverizing a sodium silicate solid having a water content of 5 to 30% by weight, and the particulate foaming. A mixing step of mixing the agent and the thermoplastic resin material to form a mixture, and heating the mixture at a temperature equal to or higher than the melting point of the thermoplastic resin material to foam the foaming agent to form a large number of bubble portions. A heating foaming step of forming a film of the molten thermoplastic resin material on the outer periphery of the bubble portion, and a coating of the molten thermoplastic resin material solidified by cooling to form a coating between a large number of bubble portions. A method for producing a foamed molded product, which comprises a cooling step of obtaining a foamed molded product formed by connecting them. In the foaming agent forming step, a water-soluble alkali silicate having a molar ratio of 2 to 3.2 is mixed with a borane compound such as borosand and boric acid and a water-soluble metal compound such as magnesium hydroxide, calcium hydroxide and aluminum hydroxide. Alternatively, a claim is characterized in that two or more kinds are combined, and each of them is mixed and dissolved in an amount of 5 to 15% by weight and treated so as to have a water content of 5 to 30% by weight to form a particulate foaming agent. Item 5. The method for producing a foamed molded product according to Item 5.