Composite molded member and method for manufacturing composite molded member

Abstract

To provide a composite molded member which can be molded into a precise shape by injection molding while having inorganic physical properties such as high load bearing performance, and to provide a composite molded member.SOLUTION: The composite molded member 1 is obtained by bonding inorganic powder 10 and an organic binder 20 through a compatibilizer 30, and has an outer shape molded by a mold for heat molding. The method for producing a composite molded member includes a step of heating and melting a mixture A of an inorganic powder 10, an organic binder 20 and a compatibilizer 30, and a step of injecting the mixture A into a mold and molding the mixture.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a composite molded member and a composite molded member, and more particularly to a composite molded member and a composite molded member that can be molded into a precise shape by injection molding while having inorganic physical properties such as high load-bearing capacity. [Background technology]

[0002] BACKGROUND ART Concrete embedding members that are embedded in concrete are used in pouring the skeleton of a reinforced concrete structure, in the manufacturing process of secondary concrete products, and the like. Patent Documents 1 and 2 disclose mortar reinforcing bar spacers, but according to the Japan Society of Civil Engineers' Standard Specifications for Concrete, reinforcing bar spacers on the surface that bears the weight of the reinforcing bars should preferably be made of concrete or mortar, with mortar being the overwhelming majority of products. Mortar reinforcing bar spacers are manufactured by pouring mortar into a formwork at normal pressure, just like in the manufacture of regular concrete products. Patent Documents 3 and 4 disclose spacers for reinforcing bars made of synthetic resin such as polypropylene, Patent Document 5 discloses a curing spacer made of synthetic resin, Patent Document 6 discloses a spacer for piping made of synthetic resin, and Patent Document 7 discloses a bolt insert made of synthetic resin. In addition, concrete products and synthetic resin products are used in a variety of products, such as set plates for holding concrete products, plastic cones for holding formwork, tensile materials as substitutes for rebar, concrete blocks, Braille blocks, inserts for vending machine support blocks, building blocks, toy figurines, display holders, mobile phone holders, bookends, pen stands, and acupressure pads. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-179309 [Patent Document 2] Utility Model Registration No. 3204073 [Patent Document 3] Japanese Patent Publication No. 2020-172807 [Patent Document 4] Utility Model Registration No. 3246187 [Patent Document 5] Japanese Patent Application Laid-Open No. 2002-166411 [Patent Document 6] Japanese Patent Application Publication No. 7-280143 [Patent Document 7] Utility Model Registration No. 3182737 Summary of the Invention [Problem to be solved by the invention]

[0004] The conventional mortar products (hereinafter, "mortar" is used to include concrete) have the following problems. <1> Because the mold filling ability during manufacturing is low, there is little freedom in the shape, resulting in a simple shape and low functionality. <2> Its low impact resistance makes it susceptible to cracking when hit or dropped. In addition, the compressive strength depends on the mortar mix, so strength can vary from product to product. <3> Because of its weight, it takes effort to transport and is difficult to handle. <4> Since the production process involves pouring mortar into a formwork, removing the formwork, and curing, productivity is low.

[0005] The synthetic resin products of the prior art have the following problems. <1> It has low load-bearing capacity and is prone to buckling and cracking under load. <2> Because the linear expansion coefficient is different from that of concrete, if it is buried in concrete, gaps may form between it and the concrete after it is put into service, which could become a route for water and salt to enter. <3> When concrete is demolished after use and recycled aggregate is produced, it is necessary to remove the synthetic resin products embedded in the concrete, which makes the process complicated and may hinder the reuse of concrete.

[0006] SUMMARY OF THE INVENTION An object of the present invention is to provide a composite molded member that solves the above problems. [Means for solving the problem]

[0007] The composite molded member of the present invention is characterized in that it is made by binding an inorganic powder and an organic binder via a compatibilizer, and has an outer shape formed by a mold for hot molding.

[0008] In the composite molded member of the present invention, the weight ratio (A:B) of the inorganic powder (A) to the organic binder (B) may be 30:70 to 70:30.

[0009] In the composite molded member of the present invention, the organic binder may contain a polyamide resin.

[0010] In the composite molded member of the present invention, the inorganic powder may contain powder made of cement, concrete, and / or blast furnace slag.

[0011] In the composite molded member of the present invention, the compatibilizer may contain a silane coupling agent.

[0012] The method for producing a composite molded member of the present invention is characterized by comprising the steps of heating and melting a mixture of an inorganic powder, an organic binder, and a compatibilizer to form pellets, and injecting the mixture into a mold to mold it.

[0013] In the method for producing a composite molded member of the present invention, the weight ratio (A:B) of the inorganic powder (A) to the organic binder (B) may be 30:70 to 70:30. [Effects of the Invention]

[0014] The composite molded member of the present invention has at least one of the following effects due to the above-mentioned configuration. <1> Injection molding allows for the production of precise shapes and complex structures that are not possible with conventional mortar products. <2> It is both load-bearing and shock-resistant against collisions and drops, making it less likely to break. <3> Because its linear expansion coefficient is close to that of concrete, when it is embedded in concrete, it behaves in sync with the concrete, reducing the occurrence of gaps and ensuring high watertightness. <4> Since it can be manufactured using a plastic thermoforming device, there is a high degree of freedom in shape and productivity is high. <5> By crushing the concrete together without separating it, recycled aggregate can be produced, which contributes to resource recycling. [Brief explanation of the drawings]

[0015] [Figure 1A] Examples of composite molded parts [Figure 1B] Examples of composite molded parts [Figure 1C] Examples of composite molded parts [Figure 1D] Examples of composite molded parts [Figure 1E] Examples of composite molded parts [Figure 1F] Examples of composite molded parts [Figure 2] Material evaluation test results DETAILED DESCRIPTION OF THE INVENTION

[0016] The composite molded member and the method for manufacturing the composite molded member of the present invention will be described in detail below with reference to the drawings. [Example]

[0017] [Composite molding material] <1> Overall structure The composite molded member 1 of the present invention is a member that combines the high compressive strength of concrete with the high moldability of thermoplastic resin. The composite molded member 1 is formed by binding an inorganic powder 10 and an organic binder 20 via a compatibilizer 30 . The weight ratio of the inorganic powder 10 to the organic binder 20 can be set arbitrarily depending on the application, but it is desirable that it be approximately 30:70 to 70:30. The composite molded member 1 can be manufactured using a plastic heat molding device, and therefore has one feature in that it can be molded into complex shapes using a mold while retaining the physical properties of concrete, such as high load-bearing capacity.

[0018] <1.1> Uses of composite molding materials The composite molded member 1 is suitable for use as a concrete-embedded component such as a spacer for reinforcing bars, a spacer for piping, a bolt insert, a drainage pipe, or a drainage material. However, the uses of the composite molded member 1 are not limited to this, and it can be used for a variety of purposes in a variety of product fields, including other building materials, as well as household goods, sporting goods, outdoor goods, toys, stationery, novelties, and the like. Prior art concrete or mortar components for embedding in concrete had problems such as limited freedom of shape, inability to be molded into complex shapes, low impact resistance, prone to cracking, and heavy weight. Furthermore, synthetic resin components for embedding in concrete had low load-bearing capacity and were prone to buckling (cracks), and differences in linear expansion coefficients could lead to gaps between the resin and the concrete after use, creating a route for water and salt to penetrate. In contrast, the composite molded member 1 of the present invention can be molded into complex shapes using a plastic heating molding device, and since its linear expansion coefficient is close to that of concrete, it behaves in harmony with the surrounding concrete after being put into service, making it less likely to develop gaps.

[0019] <2> Inorganic powder The inorganic powder 10 is a powder that becomes the main material of the composite molded member 1. In this example, ordinary Portland cement is used as the inorganic powder 10. However, the inorganic powder 10 is not limited to this, and may be any cementitious powder such as various types of Portland cement such as high-early-strength Portland cement, blast-furnace cement mixed with fly ash or blast-furnace slag, concrete powder, sludge cake powder obtained by high-pressure dehydration of concrete sludge, etc. In addition to cementitious powders, the inorganic powder may be industrial by-products such as ground blast-furnace slag and fly ash, mineral powders such as ceramics, calcium carbonate, talc, mica, and whiskers, metal powders such as ferrite and copper, or a combination of the above powders.

[0020] <2.1> Reuse of waste materials When concrete powder is used as the amorphous powder 10, waste concrete can be reused. Here, "waste concrete" includes leftover concrete, returned concrete, concrete rubble, test pieces used in concrete compression tests, etc. Waste concrete 10 is generated at ready-mix concrete plants, demolition sites, etc., and is generally disposed of at high disposal costs. Therefore, by reusing this as inorganic powder 10 for composite molded member 1, waste disposal costs can be reduced and resources can be recycled. Concrete also reacts with carbon dioxide in the atmosphere to adsorb carbon dioxide (Ca(OH)2 + CO2 → CaCO3 + H2O). Powdered concrete, in particular, has a large surface area, so by adsorbing a large amount of carbon dioxide, the composite molded member 1 can also be equipped with a carbon dioxide storage function (CCS).

[0021] <3> organic binder The organic binder 20 is a binder that binds the inorganic powder 10 together. In this example, polyamide resin such as PA6 or PA66 is used as the organic binder 20 . However, the organic binder 20 is not limited to this, and may be a thermoplastic resin such as polypropylene resin, polycarbonate resin, elastomer resin, polyethylene resin, polyvinyl chloride resin, polystyrene resin, acrylic resin, polyester resin, polyurethane resin, polypropylene resin, or a combination thereof. In particular, polyamide resins and polycarbonate resins are self-extinguishing (flame-retardant) resins, making them suitable for use in building materials.

[0022] <4> Compatibilizer The compatibilizer 30 is a compound that makes the inorganic powder 10 and the organic binder 20 compatible with each other. In this example, a silane coupling agent is used as the compatibilizer 30. However, the compatibilizer 30 is not limited to a silane coupling agent, and various types of acid-modified polypropylene, hydrogenated styrene-based thermoplastic elastomer (SEBS), etc. may also be used as long as they can make the inorganic powder 10 and the organic binder 20 compatible.

[0023] <5> Manufacturing method The composite molded part 1 is manufactured using a plastic heat molding device, which may include, for example, a cylinder with a built-in heater, a hopper attached to the cylinder, a screw conveyor installed inside the cylinder, and a mold installed at the tip of the cylinder. The composite molded member 1 is manufactured, for example, by the following procedure. Inorganic powder 10, pellet-shaped, lumpy or powdery organic binder 20, and compatibilizer 30 are mixed in a predetermined ratio using a mixer, tumbler, etc., kneaded, melted and pelletized to produce mixture A. In the mixture A, the weight ratio of the inorganic powder 10 to the organic binder 20 is within the range of 30:70 to 70:30. The compatibilizer 30 can be blended with the inorganic powder 10 at a weight ratio of 1 to 8%, for example. Pellet-like mixture A is placed in the hopper of an injection molding machine, dropped into the cylinder, and extruded toward the mold by a screw conveyor while being heated and kneaded in the cylinder, and injected into the mold. During this process, the organic binder 20 melts and mixes uniformly with the inorganic powder 10, and the inorganic powder 10 and organic binder 20 are integrated together by the chemical bonding function of the compatibilizer 30. The injection molding machine that can be used is a twin-screw extruder, kneader-mixer, small kneader-mixer, Banbury mixer, etc. The mold is cooled and disassembled to remove the composite molded part 1. The above steps make it possible to easily manufacture a composite molded member 1 that combines the characteristics of inorganic materials, such as high load resistance and affinity with concrete, with the characteristics of organic materials, such as a dense surface and precise shape. However, the manufacturing method for the composite molded member is not limited to the above, and other methods, such as the free blend method (registered trademark), which simultaneously performs mixing and molding, may also be used.

[0024] <6> Examples of composite molded parts Figures 1A to 1F show examples of composite molded member products, all of which are examples of reinforcing bar holding members (spacers). Figure 1A shows products made with four different blends: cement:PA6 = 70:30, cement:PP = 70:30, blast furnace slag:PP = 70:30, and waste concrete:PP = 70:30. Figure 1B shows a product made with a blend of waste concrete:PP = 70:30. Figure 1C shows four shapes of products made with a blend of blast furnace slag:PA6 = 70:30. Figure 1D shows a product made with a blend of blast furnace slag:PA6 = 70:30. Figure 1E shows a product made with a blend of blast furnace slag:PA6 = 70:30. Figure 1F shows products made with three different blends: blast furnace slag:PA6 = 70:30, blast furnace slag:PA6 = 30:70, and blast furnace slag:PA6 = 40:60. Both products feature precise shapes achieved through injection molding that could not be achieved with conventional mortar products, such as thin, long holding arms that hold the rebar and multiple through holes that connect the support base from top to bottom.

[0025] <7> Material Evaluation Test A material evaluation test was carried out on the composite molded member of the present invention. Examples 1 to 18 are examples of combinations of the type of inorganic powder, the type of organic binder, the weight ratio of the inorganic powder to the organic binder, the weight ratio of the compatibilizer to the inorganic powder and the organic binder, and the method of mixing the materials. Comparative Examples 1 to 5 are examples using only an organic binder, and Comparative Example 6 is an example in which a combination of inorganic powder and an organic binder was kneaded without using a compatibilizing agent. [Evaluation items] (1) Density: JIS-K7112 (2) Tensile stress: JIS-K7161 (3) Nominal breaking strain: JIS-K7161 (4) Bending stress: JIS-K7171 (5) Flexural modulus: JIS-K7171 (6) Charpy impact value: JIS-K7111 (with notch) (7) Compressive stress: See JIS-A1108 (8) Linear expansion coefficient: JIS-K7197 (9) Shrinkage rate: proprietary method (10) Water permeability: Original method [Evaluation Procedures (1) to (8)] Test pieces of composite molded components were molded using an injection molding machine and then cured for at least 48 hours. The flexural modulus was evaluated by measuring the cross section using a 3D shape measuring device, and other evaluation methods based on JIS standards were also performed. [Evaluation Procedure (9)] In general plastic molding, the molded product shrinks as heat dissipates, and the amount of shrinkage is roughly constant depending on the material at a constant temperature, and this is defined as the shrinkage rate. The shrinkage rate is measured by molding a test specimen of the material to be measured using a test specimen mold, curing it for three days after molding, and storing it in a 23°C environment for at least 24 hours.Then, the mold dimensions of the test specimen are compared with the actual dimensions of the molded product to measure the amount of shrinkage per 1000 mm. [Evaluation Procedure (10)] The test piece is placed in a concrete formwork and concrete is poured in. After pouring, it is cured for one day, removed from the formwork, and then cured underwater for at least 14 days to produce a specimen in which the test piece penetrates both sides of the concrete from top to bottom. A water pressure of 0.1 MPa is applied to the top surface of the test specimen, and after 15 minutes it is checked to see if water is seeping out from the bottom of the test specimen. If water is not seeping out, the water pressure is increased by 0.1 MPa and the test is continued for another 15 minutes to see if water is seeping out from the bottom of the test specimen. This process is repeated until water seeps out from the bottom.

[0026] <8> Test results The results of the material evaluation test are shown in Figure 2. Items for which results have not yet been obtained at the time of application are left blank. In Examples 1 to 18, the inorganic powder and organic binder were effectively mixed together by the presence of the compatibilizer, and test pieces could be produced by injection molding. On the other hand, in Comparative Example 6, the inorganic powder and the organic binder were not mixed together, and it was not possible to manufacture a test piece by injection molding. The tensile stress and bending stress were generally good in all examples, and particularly in Examples 1 to 3 and 11 to 17, which used PA6 as the organic binder, and Example 18, which used PA66, the values ​​were at a high level. In addition, the impact strength (Charpy impact value: notched) is 0.9 to 3.4 kJ / m 2 and the impact strength of ordinary concrete (1 kJ / m 2 The range was above (around 100°C). The linear expansion coefficient is 10.1 to 61.8 × 10 in all examples. -6 / °C, and 73.9 to 97.1 × 10 -6 / ℃, the linear expansion coefficient of ordinary concrete (10 × 10 -6 Therefore, in the water permeability evaluation, no water leakage was observed up to 0.3 to 0.5 MPa, particularly in Examples 1 to 3, 11, and 12, which used PA6 as the organic binder, and high watertightness was ensured by conforming to the concrete. [Explanation of symbols]

[0027] 1 Composite molding member 10 Inorganic powder 20 Organic binder 30 Compatibilizer A mixture

Claims

1. The inorganic powder and the organic binder are bound together via a compatibilizer, The outer shape is formed by a mold for hot forming. Composite molded components.

2. The weight ratio (A:B) of the inorganic powder (A) to the organic binder (B) is 30:70 to 70:30, The composite molded member according to claim 1 .

3. The organic binder contains a polyamide resin. The composite molded member according to claim 1 or 2.

4. The inorganic powder includes powder made of cement, concrete, blast furnace slag, and / or ceramic. The composite molded member according to claim 1 or 2.

5. The compatibilizer contains a silane coupling agent. The composite molded member according to claim 1 or 2.

6. a step of heating and melting a mixture of an inorganic powder, an organic binder, and a compatibilizer to form pellets; and a step of injecting the mixture into a mold to mold it. Ru, A method for manufacturing a composite molded member.

7. The weight ratio (A:B) of the inorganic powder (A) to the organic binder (B) is 30:70 to 70:30, The method for producing the composite molded member according to claim 6.

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