Silicate foamed resin pellet and method for producing the same

Abstract

To provide a silicate foamed resin pellet in which a plurality of bubble spheres composed of silicate are dispersed within a molded product of thermoplastic resin.SOLUTION: A silicate foamed resin pellet of the present invention is a molded product having a diameter of 1 to 5 mm and a length of 1 to 10 mm, wherein the silicate foamed resin pellet is constituted by dispersing a plurality of bubble spheres composed of silicate within a molded product of a thermoplastic resin such as a super engineering plastic containing a release agent.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to silicate foam resin pellets and a method for producing the same.

Background Art

[0002] The inventor of the present application has developed a foamed molded article in which air bubbles of silicate are coated with a thermoplastic resin material, and a particulate silicate having a particle size of 500 μm or less described in Patent Document 1, or a silicate containing a boron compound such as borax or boric acid. A mixture of a foaming agent and a thermoplastic resin material is heated 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, and a film of the molten thermoplastic resin material is formed on the outer periphery of the bubble portions. The obtained foamed molded article was pulverized based on this invention with the aim of obtaining silicate foam resin molded articles of various shapes by applying it to various molding apparatuses, and silicate foam resin pellets of molded articles having a diameter of 1 to 5 mm and a length of 1 to 10 mm were produced. Then, the silicate foam resin pellets were applied to an injection molding apparatus. However, in the process of filling the silicate foam resin pellets into the molding die of the injection molding apparatus, it was found that the silicate foam resin pellets adhered to the screw in the heating cylinder for filling the molding die, resulting in poor productivity and inability to obtain desirable air bubbles. Therefore, based on the inventor's experience of applying a release agent to the surface of the molding die, an invention was created to obtain silicate foam resin pellets containing the release agent, and it was found that it is useful to form the silicate foam resin pellets into a columnar shape by an extruder and cut this into a molded article having a diameter of 1 to 5 mm and a length of 1 to 10 mm for production.

[0003] Patent Document 2 proposes a method for manufacturing foaming agent composition pellets used in the foam molding of thermoplastic resins. After kneading with a batch kneader, the pellets are manufactured into pellet form using an extruder and a pelletizer. As an apparatus for manufacturing the foaming agent composition pellets, a Banbury mixer, a rocking mixer (manufactured by Aichi Electric Co., Ltd.), a high-speed mixer (manufactured by Fukae Powtec Co., Ltd.), a Henschel mixer (manufactured by Mitsui Miike Co., Ltd.), a universal stirrer (manufactured by Dalton Co., Ltd.), a Nauta mixer (manufactured by Hosokawa Micron Corporation), a CF granulator (manufactured by Freund Industry Co., Ltd.), a vertical granulator (manufactured by Pauleck Co., Ltd.), a flow jet granulator (manufactured by Okawara Seisakusho Co., Ltd.), a roll press DP type (manufactured by Seishin Enterprise Co., Ltd.), an RCP type roller compactor (manufactured by Kurimoto Iron Works Co., Ltd.), a briquettor BGS-IV·II (manufactured by Shin To Kogyo Co., Ltd.), a disk pelletizer (manufactured by Fuji Paudal Co., Ltd.), a twin-screw extrusion granulator (manufactured by Fuji Paudal Co., Ltd.), etc. can be used. Paragraph No. 0037 states that it is effective to use the foaming agent composition pellets for high-temperature processing resins such as these engineering plastics. Further, Paragraph No. 0038 states that a mold release stabilizer may be added to the thermoplastic resin.

[0004] However, even in Patent Document 2 regarding the manufacturing method of the foaming agent composition pellets, there is no description about manufacturing silicate foam resin pellets in which a plurality of bubble spheres made of silicate are dispersed in the molded body of the thermoplastic resin. Also, although Patent Document 2 states that a mold release stabilizer may be added to the thermoplastic resin, there is no description about the fact that the presence of a mold release agent is essential for applying the silicate foam resin pellets to various molding apparatuses to obtain silicate foam resin pellets.

[0005]

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] An object of the present invention is to provide a silicate foamed resin pellet in which a plurality of bubble spheres made of silicate are dispersed in a molded body of a thermoplastic resin.

MEANS FOR SOLVING THE PROBLEMS

[0008] The silicate foamed resin pellet according to claim 1 of the present invention is a silicate foamed resin pellet of a molded body having a diameter of 1 to 5 mm and a length of 1 to 10 mm, and a plurality of bubble spheres made of silicate are dispersed in a molded body of a thermoplastic resin containing a release agent. Further, the silicate foamed resin pellet according to claim 2 is the silicate foamed resin pellet according to claim 1, wherein the thermoplastic resin is a super engineering plastic, and the release agent is a low molecular weight silicone oil, fluorine-based release agent or low molecular weight polyethylene-based release agent, the silicate has a particle size of 1 to 500 μm, the water content of the silicate particles is 5 to 30%, the mixing ratio of the silicate particles and the super engineering plastic is 10 to 50 and 50 to 90, and the release agent is 0.1 to 3% based on 100 of the silicate particles and the super engineering plastic. Further, the silicate foamed resin pellet according to claim 3 is the silicate foamed resin pellet according to claim 1 or 2, wherein the silicate contains a boron compound such as borax or boric acid. The method for producing a silicate foamed resin pellet according to claim 4 of the present invention is a method for producing a silicate foamed resin pellet in which a plurality of bubble spheres made of silicate are dispersed in a molded body of a thermoplastic resin containing a release agent, and the method comprises a stirring and mixing step of stirring and mixing silicate particles, thermoplastic resin particles and a release agent or silicate particles containing a boron compound such as borax or boric acid, thermoplastic resin particles and a release agent to obtain a stirred mixture, an extrusion molding step of forming the stirred mixture into a columnar molded body by an extruder, and a cutting step of cutting the columnar molded body to have a diameter of 1 to 5 mm and a length of 1 to 10 mm.

Advantages of the Invention

[0009] The silicate foam resin pellets of the present invention can disperse a plurality of bubble spheres made of silicate in a molded body of a thermoplastic resin.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0011] (Silicate Foam Resin Pellets) Figs. 1 and 2 show embodiments of the silicate foamed resin pellets of the present invention. The silicate foamed resin pellet 1 is a molded body with a diameter of 1 to 5 mm, preferably 2 to 3 mm, and a length of 1 to 10 mm, preferably 2 to 4 mm. A plurality of bubble spheres 3 made of silicate are dispersed in a molded body 2 of a thermoplastic resin containing a mold release agent. This silicate is formed into particles with a particle size of 1 to 500 μm by treating an aqueous sodium silicate solution with a molar ratio of 2 to 3.2 to have a moisture content of 5 to 30 wt%. Examples of the thermoplastic resin of the molded body 2 include olefin resins such as polyethylene and polypropylene, polyvinyl chloride resin, ABS resin, polyamide resin, polyester resin, and fluororesin. Further, super engineering plastics such as polyphenylene sulfide (PPS), polyether ether ketone (PEEK), thermoplastic polyimide (LARC-PAI), polyamideimide, polyarylamide, polyetherimide, polyphenylene sulfone (PPSU), and polymethacrylimide (PMI) can be exemplified. Examples of the mold release agent contained in the thermoplastic resin molded body 2 include low molecular weight silicone oil, fluorine-based mold release agent, or low molecular weight polyethylene-based mold release agent. An anti-rust agent may be used as needed. In the silicate foamed resin pellet 1 made of such a silicate particle, thermoplastic resin, and mold release agent, with the thermoplastic resin being a super engineering plastic, the mixing ratio of the silicate particle with a particle size of 1 to 500 μm and a moisture content of 5 to 30% and the super engineering plastic is 10 to 50 and 50 to 90, and the mold release agent is contained in an amount of 0.1 to 3% based on 100 of the silicate particle and the super engineering plastic.

[0012] Regarding the silicate particles in the silicate foam resin pellets 1 of the present invention, not only the silicate particles but also the silicate particles containing boron compounds such as borax and boric acid are processed so as to have a moisture content of 5 to 30% by weight and formed into particles with a particle size of 1 to 500 μm, whereby the silicate foam resin pellets 1 with improved strength, heat insulation properties, and dielectric constant can be obtained. Thus, when silicate foam resin pellets 1 with improved strength, heat insulation properties, and dielectric constant are required, silicate particles containing boron compounds such as borax and boric acid may be employed, and thus, it is described as silicate particles or silicate particles containing boron compounds such as borax and boric acid.

[0013] (Method for manufacturing silicate foam resin pellets) Figure 3 shows the manufacturing process of the silicate foam resin pellets of the present invention, which is a manufacturing method for obtaining silicate foam resin pellets 1 in which a plurality of bubble spheres 3 made of silicate are dispersed in a molded body 2 of a thermoplastic resin, and includes a stirring and mixing step 101 for obtaining a stirred mixture, an extrusion molding step 102 for forming a columnar molded body, and a cutting step 103 for cutting to a diameter of 1 to 5 mm and a length of 1 to 10 mm. First, in the stirring and mixing step 101, the silicate particles, the thermoplastic resin particles, and the release agent are stirred and mixed to obtain a stirred mixture, or the silicate particles containing boron compounds such as borax and boric acid, the thermoplastic resin particles, and the release agent are stirred and mixed to obtain a stirred mixture. In this case, the silicate particles or the silicate particles containing boron compounds such as borax and boric acid, the thermoplastic resin particles, and the release agent may be stirred and mixed at once, but after stirring and mixing the silicate particles or the silicate particles containing boron compounds such as borax and boric acid and the thermoplastic resin particles, the release agent may be added and stirred and mixed to obtain a stirred mixture by two-stage stirring and mixing. Next, in the extrusion molding step 102, this stirred mixture is extruded by an extruder and cooled to obtain a columnar molded body in which a plurality of bubble spheres 3 are dispersed inside. In this case, a twin-screw extruder is preferably used as the extruder. Next, in the cutting step 103, this columnar molded body is cut to a diameter of 1 to 5 mm and a length of 1 to 10 mm to obtain silicate foam resin pellets 1 in which a plurality of bubble spheres 3 made of silicate are dispersed in a molded body 2 of a thermoplastic resin.

Example

[0014] In the silicate foam resin pellet 1 of the present invention, the thermoplastic resin of the molded body 2 is a super engineering plastic. As a representative example, polyphenylene sulfide (PPS) is selected. MB-600G of DIC and silicate grains with a particle size of 20 to 45 μm and a moisture content of 18% are stirred and mixed at a ratio of 90 to 10. Then, 0.5% of a release agent "polyethylene wax PE-190" and a rust preventive agent "AZO" are added to the mixture and continuously stirred and mixed. The mixture is put into a twin-screw extruder and molded by the twin-screw extruder at atmospheric pressure without reducing the pressure to obtain a silicate foam resin pellet 1 of a molded body with a diameter of 2.0 mm and a length of 2.6 mm. As a result of observing the cross section of the silicate foam resin pellet 1, it was confirmed that a plurality of bubble spheres 3 exist as shown in FIG. 4. In this example, since molding is performed by a twin-screw extruder at atmospheric pressure without reducing the pressure, generation of large holes was confirmed in addition to these bubble spheres 3.

[0015] (Description of a molded product applied to an injection molding apparatus as a molding apparatus) The silicate foam resin pellet of the present invention is applied to an injection molding apparatus, and the cross section of an injection molded product obtained by using a molding machine of Sodic TR10EH2 with a screw temperature in the heating cylinder of 310 ° C, a molding die temperature of 50 ° C, an injection speed of 70 mm / sec, an injection pressure of 50 mPa, and a holding pressure of 30 mPa was observed. As a result, as shown in FIG. 5, the presence of a plurality of large and small bubble spheres with a diameter of 50 to 100 μm was confirmed.

Industrial Applicability

[0016] The silicate foam resin pellet of the present invention is useful for obtaining molded products of various shapes when applied to an injection molding apparatus or an extrusion molding apparatus.

Explanation of Reference Numerals

[0017] 1 Silicate foam resin pellet 2 Molded body 3 Bubble sphere 101 Stirring and mixing process 102 Extrusion forming process 103 Cutting process

Claims

1. A silicate foam resin pellet of a molded body with a diameter of 1 to 5 mm and a length of 1 to 10 mm, characterized in that a plurality of bubble spheres made of silicate are dispersed in a molded body of a thermoplastic resin containing a mold release agent.

2. The thermoplastic resin is a super engineering plastic, the mold release agent is a low molecular weight silicone oil, fluorine-based mold release agent or low molecular weight polyethylene-based mold release agent, the silicate has a particle size of 1 to 500 μm, the water content of the silicate particles is 5 to 30%, the mixing ratio of the silicate particles and the super engineering plastic is 10 to 50 and 50 to 90, and the mold release agent is made by containing 0.1 to 3% with 100 of the silicate particles and the super engineering plastic. The silicate foam resin pellet according to Claim 1, characterized in that it is.

3. The silicate foam resin pellet according to Claim 1 or 2, characterized in that the silicate contains a boron compound such as borax or boric acid.

4. A method for producing a silicate foam resin pellet in which a plurality of bubble spheres made of silicate are dispersed in a molded body of a thermoplastic resin containing a mold release agent, the silicate particles, the thermoplastic resin particles and the mold release agent, or the silicate particles containing a boron compound such as borax or boric acid, the thermoplastic resin particles and the mold release agent are stirred and mixed to obtain a stirred mixture, an extrusion molding step of forming the stirred mixture into a columnar molded body with an extruder, and a cutting step of cutting the columnar molded body so that the diameter becomes 1 to 5 mm and the length becomes 1 to 10 mm. A method for producing a silicate foam resin pellet, characterized by comprising:

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