Resin composition, resin molded article, and method for producing resin molded article

Abstract

To provide a resin composition having good impact strength and moldability.SOLUTION: The resin composition includes a recycled material made of a resin and an inorganic water-absorbing material in a range of 0.1 to 20 mass%.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a resin composition, a resin molded article, and a method for producing a resin molded article. [Background technology]

[0002] Conventionally, resin molded products have been used in various fields such as automobiles and home appliances due to their impact resistance and moldability. In recent years, from the viewpoint of environmental conservation, there has been a demand for reducing the amount of waste resin molded products. Therefore, used, collected products (recovered products) are used as raw materials for new products. Recovered products are easily subject to moisture content because they are processed through processes such as crushing and cleaning before becoming raw materials for new products. When recycled products with a high moisture content are used as raw materials for molding using injection molding or the like, molding defects known as silver streaks occur. In a method for manufacturing resin molded products using recycled products with a high moisture content as raw materials, the moisture is removed by pre-drying the raw materials (see, for example, Patent Document 1).

[0003] Patent Document 1 describes a method for producing a resin molded body, which includes a step of melting a raw material containing a thermoplastic resin and a step of obtaining a resin molded body by injection molding the molten raw material. In the step of melting the raw material, the moisture content of the raw material is reduced by extending the drying time before melting. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 8-231819 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the manufacturing method described in Patent Document 1 requires a long heating time, which may result in low manufacturing efficiency of the resin molded body. In this case, adding a water-absorbing material to the raw material may be considered, but if the content of the water-absorbing material is high, it is thought that the impact strength of the resin molded body will decrease.

[0006] An object of the present invention is to provide a resin composition having excellent impact strength and moldability, a resin molded article, and a method for producing a resin molded article. [Means for solving the problem]

[0007] A resin composition according to one embodiment of the present invention contains a recycled resin material and an inorganic water-absorbing material in the range of 0.1 to 20 mass %.

[0008] A resin molded article according to one embodiment of the present invention is molded using the resin composition of the present invention.

[0009] A method for producing a resin molded body according to one embodiment of the present invention includes a step of kneading a resin composition containing a recycled resin material and an inorganic water absorbent in the range of 0.1 to 20 mass % to obtain a kneaded mixture, and a step of using the kneaded mixture to obtain a resin molded body by injection molding. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a resin composition having excellent impact strength and moldability, a resin molded article, and a method for producing a resin molded article. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a flowchart of a method for producing a resin molded body. DETAILED DESCRIPTION OF THE INVENTION

[0012] A resin composition, a resin molded product, and a method for manufacturing a resin molded product according to one embodiment of the present invention will be described below. The present invention is not limited to the following embodiment. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​written before and after "to" as the lower and upper limits. In the following description, the resin composition used in the method for manufacturing a resin molded product will be described, followed by a description of the method for manufacturing a resin molded product and the resin molded product.

[0013] [Configuration of resin composition] The resin composition of the present embodiment includes a recycled resin material and an inorganic water absorbent material.

[0014] The recycled material is made of thermoplastic resin. Examples of thermoplastic resins include polyethylene (PE), polypropylene (PP), polystyrene (PS), acrylonitrile-butadiene-styrene copolymer (ABS resin), acrylonitrile-styrene resin (AS resin), polycarbonate (PC), polyethylene terephthalate (PET), and polybutylene terephthalate (PBT). Of the thermoplastic resins, styrene-based resins are preferred. Examples of styrene-based resins include acrylonitrile-butadiene-styrene copolymer (ABS resin), acrylonitrile-styrene resin (AS resin), and polystyrene (PS). Of the styrene-based resins, resins with a structure in which acrylonitrile and styrene are bonded are more preferred. Examples of resins with a structure in which acrylonitrile and styrene are bonded include acrylonitrile-butadiene-styrene copolymer (ABS resin) and acrylonitrile-styrene resin (AS resin).

[0015] The recycled material may be used alone or in combination with several other types. Preferably, the recycled material contains ABS resin or AS resin as its main component. Here, "main component" refers to the resin component that is most abundant among the resins contained in the recycled material.

[0016] The content of the recycled material in the resin composition is preferably in the range of 80 to 99 mass %, more preferably in the range of 95 to 99 mass %.

[0017] The inorganic water absorbent absorbs moisture contained in the resin composition. Generally, a water absorbent is added to remove moisture absorbed by an item contained in a resin molded body (container) molded from the resin composition. However, in this embodiment, the inorganic water absorbent is added to absorb moisture contained in the resin composition. As described above, the function of the inorganic water absorbent in this embodiment differs from that of conventional water absorbents. The inorganic water absorbent is not particularly limited as long as it can exhibit the above-mentioned function. The inorganic water absorbent preferably contains aluminum oxide, calcium oxide, or zeolite. One type of inorganic water absorbent may be used alone, or multiple types may be used in combination.

[0018] The content of the inorganic water absorbing material is in the range of 0.1 to 20% by mass, and more preferably in the range of 1 to 6% by mass. If the content of the inorganic water absorbing material exceeds 20% by mass, it becomes a foreign substance in the resin composition, and the impact strength of the resin molded product decreases. As described above, the inorganic water absorbing material contained in this embodiment is added to absorb the moisture contained in the resin composition, so there is no need to add more than necessary.

[0019] In addition to the above components, the resin composition may contain additives such as colorants, flame retardants, lubricants, compatibilizers, antioxidants, and UV absorbers. The additives may be used alone or in combination of two or more. Furthermore, the resin composition may contain unused thermoplastic resin products (virgin materials) that have been collected before being released to the market. The type of resin in the unused material (virgin material) is not particularly limited as long as it is a thermoplastic resin. The type of resin in the unused material (virgin material) may be the same as or different from the type of recycled material.

[0020] Examples of colorants include inorganic pigments and organic pigments. Examples of flame retardants include phosphorus-based compounds such as phosphate esters and bromine compounds. Examples of lubricants include metal salts of higher fatty acids and higher fatty acid amides. Examples of compatibilizers include random copolymer-based, graft copolymer-based, and block polymer-based compatibilizers. Examples of antioxidants include hindered phenol-based, sulfur-containing organic compound-based, and phosphorus-containing organic compound-based antioxidants. Examples of ultraviolet absorbers include benzotriazole-based, benzophenone-based, and salicylate-based ultraviolet absorbers.

[0021] The content of the additive is preferably 0.3% by mass or more, more preferably 0.5% by mass or more, from the viewpoint of exerting the effect of adding the additive, and is preferably 20% by mass or less, more preferably 15% by mass or less, from the viewpoint of not affecting melt-kneading.

[0022] [Method of manufacturing resin molded body] Fig. 1 is a flowchart of a method for producing a resin molded body. A resin molded body using the above-mentioned resin composition can be produced, for example, by the following method. As shown in Fig. 1, the method for producing a resin molded body includes a step (S110) of kneading a resin composition containing recycled material and an inorganic water-absorbing material to obtain a kneaded mixture, and a step (S120) of injection-molding the kneaded mixture to obtain a resin molded body.

[0023] In the step (S110) of obtaining a kneaded material, the recycled material and inorganic water-absorbing material are kneaded at a predetermined temperature to obtain a kneaded material. Virgin material or other additives may be added as needed. The recycled material is made of resin, preferably containing a styrene-based resin, and more preferably containing a resin having a structure in which acrylonitrile and styrene are bonded. The content of the inorganic water-absorbing material is within the range of 0.1 to 20% by mass, more preferably within the range of 1 to 6% by mass. The inorganic water-absorbing material is preferably aluminum oxide, calcium oxide, or zeolite.

[0024] The kneading temperature is not particularly limited as long as it is a temperature at which the resin composition can be melted. The kneading temperature is appropriately set depending on the resin composition. The kneading temperature is a temperature equal to or higher than the melting point. The kneading temperature is preferably within the range of 200 to 260°C.

[0025] The kneading time is not particularly limited as long as the resin composition is melted. In the present embodiment, since the resin composition contains 0.1 to 20 mass % of an inorganic water-absorbing material, a kneaded product can be obtained in the same time as a resin composition containing no recycled material and containing virgin material.

[0026] The order of kneading is not particularly limited. The recycled material, inorganic water-absorbing material, virgin material, and additives may be added and kneaded simultaneously, or the recycled material, virgin material, and additives may be added first, followed by the inorganic water-absorbing material, or they may be added in any other order. Also, the recycled material may be melted to remove most of the moisture, and then the inorganic water-absorbing material may be added to remove the remaining moisture.

[0027] In the step (S120) of obtaining a resin molded body, the kneaded mixture is used to obtain a resin molded body. Specifically, for example, the resin composition is poured into a heated mold and cured. Finally, the mold is released to obtain the resin molded body.

[0028] [Resin molding] The resin molded article of the present embodiment is molded using the resin composition described above. The shape of the resin molded article is not particularly limited. The shape of the resin molded article is appropriately set depending on the intended use.

[0029] (effect) As described above, the resin composition, resin molded body, and method for manufacturing a resin molded body according to this embodiment contain recycled resin material and an inorganic water absorbent material in the range of 0.1 to 20% by mass, and therefore have good impact strength and moldability. [Example]

[0030] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples.

[0031] 1. Preparation of resin molded body Example 1 GAR011 (Kingfa Technology Co., Ltd.), an ABS resin made of 95% recycled material, and NP-ALO-3 (EM Japan Co., Ltd.), an aluminum oxide, 5% by mass was mixed in a twin-screw mixer TEX-25 (The Japan Steel Works, Ltd.) at a mixing temperature of 200°C and a rotation speed of 200 rpm. The mixed mixture was pre-dried at 80°C for 4 hours and then molded at a molding temperature of 220°C using an injection molding machine JSW-AD110 (The Japan Steel Works, Ltd.) to obtain a resin molded body 1 of Example 1.

[0032] Examples 2 to 6, Comparative Examples 1 and 2 Resin molded articles 2 to 8 of Examples 2 to 6 and Comparative Examples 1 and 2 were produced in the same manner as Resin composition 1 of Example 1, except that the compositions were changed as shown in Table 1 below.

[0033] The recycled PS resin used in Table 1 was 510R95 (Kingfa Science & Technology Co., Ltd.). The calcium oxide used was F-Lime 1300K (Calfine Corporation). The zeolite used was Zeolum (registered trademark) A-4 (Tosoh Corporation).

[0034] 2. Measurement of moisture loss rate Using a heat-drying moisture meter (MX-50: A&D Co., Ltd.), each resin molded body was dried at 140°C for 10 minutes to measure the moisture loss rate (weight loss rate).

[0035] 3. Evaluation of formability The kneaded material was continuously molded into 10 test pieces measuring 90 mm x 50 mm x 2 mm using an injection molding machine set at an injection temperature of 220°C. The test pieces were visually inspected for the occurrence of silver streaks. Moldability was evaluated according to the following criteria. Evaluation results of "△" and "○" were considered to be acceptable. ○: No silver streaks occurred. △: A slight amount of silver streaks occurred. ×: Silver streaks were observed intensely.

[0036] 4. Impact strength evaluation The impact strength was measured using a Charpy impact test in accordance with JIS K7111-1:2016. The measurement samples used were rectangular test pieces cut to 80 x 10 x 4 mm and notched to shape A. The nominal pendulum energy was 4 J. The impact strength was evaluated according to the following criteria. ○: Impact strength is 10kJ / m 2 That was all. ×: Impact strength is 10 kJ / m 2 It was less than.

[0037] Table 1 shows the composition of each resin molded body and the evaluation results.

[0038] [Table 1]

[0039] 5. Evaluation As shown in Table 1, resin moldings 1 to 6 of Examples 1 to 6, which contained recycled resin materials and 0.1 to 20% by mass of inorganic water-absorbing material, had good impact strength and moldability. This is thought to be because the inorganic water-absorbing material was contained in an amount of 0.1 to 20% by mass, which allowed moldability to be obtained while maintaining impact strength.

[0040] The resin molded body 7 of Comparative Example 1, which did not contain an inorganic water-absorbing material, had poor moldability. This is thought to be because the gas (water vapor) in the resin composition was stretched inside the mold due to the absence of an inorganic water-absorbing material. The resin molded body 8 of Comparative Example 2, which contained more than 20% by mass of inorganic water-absorbing material, had low impact strength. This is thought to be because the inorganic water-absorbing material was too much relative to the recycled resin, and became a foreign substance in the resin composition. [Industrial Applicability]

[0041] The resin composition of the present invention, the method for producing a resin molded body using the resin composition, and the resin molded body obtained by the method for producing a resin molded body are expected to enable the reuse of recovered materials, increased effective use of resin materials, and further reduction of the burden on the environment.

Claims

1. Recycled resin materials and 0.1 to 20% by mass of an inorganic water absorbent material; A resin composition comprising:

2. The recycled material includes a styrene-based resin. The resin composition according to claim 1.

3. The resin composition according to claim 1 , wherein the inorganic water-absorbing material comprises aluminum oxide, calcium oxide, or zeolite.

4. The resin composition according to claim 1, wherein the content of the inorganic water absorbent is in the range of 1 to 6 mass %.

5. The resin composition according to claim 1 , wherein the recycled material comprises a resin having a structure in which acrylonitrile and styrene are bonded.

6. A resin molded product molded using the resin composition according to any one of claims 1 to 5.

7. A step of kneading a resin composition containing a recycled resin material and an inorganic water-absorbing material in an amount of 0.1 to 20 mass % to obtain a kneaded product; obtaining a resin molded body by injection molding using the kneaded mixture; having A method for manufacturing a resin molded product.

8. The method for producing a resin molded product according to claim 7, wherein the kneading temperature in the step of obtaining a kneaded product by kneading is within a range of 200 to 260°C.

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