Regenerated polystyrene foam material and preparation method therefor

Abstract

A regenerated polystyrene foam material and a preparation method therefor. The preparation method comprises: weighing an appropriate amount of polystyrene, carrying out melting, extrusion and granulation to obtain granules, and drying the granules; uniformly mixing the dried granules, a modification auxiliary agent, and a silane coupling agent, carrying out melting, extrusion and granulation to obtain preliminarily processed granules, and drying the preliminarily processed granules; mixing the dried preliminarily processed granules with azodicarbonamide and a cell regulator, and carrying out melting, foaming, and extrusion to obtain a polystyrene foam material; and cooling and shaping the polystyrene foam material and carrying out traction cutting to obtain a finished product. By using a styrene-butadiene-styrene block copolymer as a modifier and blending a small amount of SBS with polystyrene, the low-temperature performance and the impact strength of an article can be significantly improved; moreover, with the assistance of the silane coupling agent, the tensile performance and the impact resistance of the polystyrene foam material can be greatly improved.

Description

Recycled polystyrene foam material and preparation method Technical Field

[0001] The present invention relates to the field of foam materials, in particular to a recycled polystyrene foam material and a preparation method thereof. Background Art

[0002] Polystyrene refers to a polymer synthesized from styrene monomers via free radical addition polymerization. It is a colorless, transparent thermoplastic with a glass transition temperature exceeding 100°C. Therefore, it is often used in various disposable containers that must withstand boiling water, as well as disposable foam lunch boxes. Polystyrene can polymerize via free radical or ionic mechanisms in the presence of an initiator or catalyst. Industrially produced polystyrene is polymerized using a free radical mechanism using an initiator. Polymerization can be carried out in bulk, suspension, solution, or emulsion.

[0003] Expanded polystyrene, also known as expandable polystyrene, has the advantages of low relative density, low thermal conductivity, low water absorption, impact and vibration resistance, heat insulation, sound insulation, moisture resistance, vibration reduction, and excellent dielectric properties. It is widely used in shockproof packaging materials for mechanical equipment, instruments and meters, household electrical appliances, handicrafts, and other fragile and valuable products, as well as fast food packaging. There are two main molding processes:

[0004] (1) One-step extrusion route, in which EPS particles are directly hot extruded after foaming. This method is mostly used to make sheets and films.

[0005] (2) Molding route: First, the EPS particles are pre-foamed 30 to 50 times with air (or water vapor) at 100°C, and then left for 24 hours to mature. The matured pre-foamed material is then placed in a mold made of aluminum or castings and heated with air (or water vapor) at 115 to 120°C. As the material expands, the surfaces of the particles fuse together to form a foamed part due to the heat.

[0006] At present, in actual application, polystyrene foam materials have limited application scope and certain defects due to their low tensile strength and impact resistance.

[0007] Summary of the Invention

[0008] The object of the present invention is to provide a recycled polystyrene foam material and a preparation method thereof, so as to achieve the tensile properties and impact resistance of the polystyrene foam material.

[0009] In order to solve the above technical problems, the present invention provides a recycled polystyrene foam material, which comprises, by weight:

[0010] Furthermore, the modification aid is a styrene-butadiene-styrene block copolymer.

[0011] Furthermore, the content of butadiene monomer in the styrene-butadiene-styrene block copolymer is 60% to 80%.

[0012] Furthermore, it also includes a cell regulator, and the weight portion of the cell regulator is 1 to 2.5 parts.

[0013] The present invention also discloses a method for preparing a recycled polystyrene foam material, comprising:

[0014] Weigh an appropriate amount of polystyrene, melt, extrude and granulate, obtain the granules and dry them;

[0015] The dried pellets, modification aid and silane coupling agent are mixed evenly, melted, extruded and granulated to obtain preliminary processed pellets, which are then dried;

[0016] The dried preliminarily processed pellets are mixed with azodicarbonamide and a cell regulator, and melted and foamed to obtain a polystyrene foam material;

[0017] The polystyrene foam material is cooled and shaped, and then pulled and cut to obtain the finished product.

[0018] Furthermore, in the pellet preparation process, melting, extrusion and pelletization are performed by a first twin-screw extruder.

[0019] Furthermore, the temperature range of the heating zone of the first twin-screw extruder is 180° C. to 210° C., and the temperature of the heating zone rises uniformly. The rotation speed of the first twin-screw extruder is 290 r / min to 310 r / min.

[0020] Furthermore, during the preparation of the primary pellets, the dried pellets, the modifying agent and the silane coupling agent are uniformly mixed by a high-speed mixer, and then melted, extruded and pelletized by a second twin-screw extruder.

[0021] Furthermore, the temperature range of the heating zone of the second twin-screw extruder is 170° C. to 200° C., and the temperature of the heating zone rises evenly. The rotation speed of the second screw extruder is 280 r / min to 310 r / min.

[0022] Furthermore, the foaming rate of the polystyrene foam material is 2.1 to 2.8.

[0023] Compared with the prior art, the present invention has at least the following beneficial effects:

[0024] The present invention uses styrene-butadiene-styrene block copolymer as a modifier, and a small amount of SBS is blended with polystyrene to significantly improve the low-temperature performance and impact strength of the product. SBS as an adhesive has the characteristics of high solid content, fast drying, and low-temperature resistance. At the same time, combined with a silane coupling agent, it can greatly improve the tensile properties and impact resistance of the polypropylene foam material. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG1 is a flow chart of the method for preparing recycled polystyrene foam material according to the present invention. DETAILED DESCRIPTION

[0026] The following is a more detailed description of the recycled polystyrene foam material and preparation method of the present invention, with reference to schematic diagrams. Preferred embodiments of the present invention are shown, and it should be understood that those skilled in the art may modify the present invention described herein while still achieving the advantageous effects of the present invention. Therefore, the following description should be understood as generally known to those skilled in the art and is not intended to limit the present invention.

[0027] The present invention is described in more detail in the following paragraphs by way of example with reference to the accompanying drawings. The advantages and features of the present invention will become more apparent from the following description and claims. It should be noted that the drawings are greatly simplified and not to exact scale, and are provided solely for the purpose of assisting in the description of the embodiments of the present invention.

[0028] Example 1

[0029] The embodiment of the present invention provides a recycled polystyrene foam material, which comprises, by weight:

[0030] Specifically, the recycled polystyrene foam material can be prepared in the amounts shown in the following table, based on weight.

[0031] In the three groups of ratios, the amount of the modifying agent was changed while keeping the amounts of other ingredients unchanged, and the relationship between the impact strength of polystyrene foam material and the modifying agent was explored.

[0032] In one specific embodiment, the modifying agent is a styrene-butadiene-styrene block copolymer, wherein the butadiene monomer content of the styrene-butadiene-styrene block copolymer is 60% to 80%. During preparation, a styrene-butadiene-styrene block copolymer with a butadiene monomer content of 70% is used. Styrene-butadiene-styrene block copolymer (SBS) is a triblock copolymer composed of styrene and butadiene. It is the world's largest thermoplastic elastomer with properties most similar to rubber.

[0033] Using styrene-butadiene-styrene block copolymer as a modifier and blending a small amount of SBS with polystyrene can significantly improve the low-temperature performance and impact strength of the product; SBS as an adhesive has the characteristics of high solid content, quick drying, and low-temperature resistance, which can greatly improve the performance of polypropylene foam materials.

[0034] Furthermore, it also includes a cell regulator, and the weight portion of the cell regulator is 1 to 2.5 parts.

[0035] Specifically, the cell regulator gives the polypropylene foam material higher melt strength, better plasticizing properties and fluidity, promotes the gelation of the polypropylene foam material, and makes the gas generated by the thermal decomposition of the foaming agent dissolve in the polypropylene foam material melt as quickly and completely as possible, and entangles with the molecular chains of the polypropylene foam material, greatly improving the strength and elasticity of the melt, so that the polypropylene foam material melt can produce the strength suitable for the expanding gas and the elongation required for the gas expansion, so as to ensure that the gas forms small, dense and independent bubbles during the expansion process, and can retain more uniform and dense bubbles, thereby obtaining a uniform foaming structure, lower density and better surface finish.

[0036] Example 2

[0037] As shown in FIG1 , the present invention further discloses a method for preparing a recycled polystyrene foam material, comprising:

[0038] S100, weighing an appropriate amount of polystyrene, melting, extruding and granulating, obtaining pellets and drying them.

[0039] Specifically, the polypropylene foam material was prepared according to the ratio of the ingredients in the formula of Example 1:

[0040] An appropriate amount of polystyrene is melted, extruded, and pelletized through the first twin-screw extruder. Twin-screw extruders, developed based on single-screw extruders, are widely used in the molding of extruded products due to their excellent feeding performance, mixing and plasticizing properties, degassing performance, and extrusion stability.

[0041] During the melting, extrusion, and pelletizing processes, the heating zone temperature of the first twin-screw extruder ranged from 180°C to 210°C, with the temperature rising uniformly. The speed of the first twin-screw extruder was 290 rpm to 310 rpm. After the pellets were produced, they were dried at 65°C to 75°C for 4.5 to 5 hours.

[0042] S200, uniformly mixing the dried pellets, the modifying aid and the silane coupling agent, and melting, extruding and granulating the pellets to obtain preliminary processed pellets, and drying the pellets.

[0043] Specifically, silane alkoxy groups are reactive toward inorganic substances, while organic functional groups are reactive or compatible with organic substances. Therefore, when a silane coupling agent is placed between the inorganic and organic interfaces, a bonding layer of organic matrix-silane coupling agent-inorganic matrix can be formed. Typical silane coupling agents include A151 (vinyltriethoxysilane), A171 (vinyltrimethoxysilane), and A172 (vinyltri(β-methoxyethoxy)silane).

[0044] During the initial pelletizing process, the dried pellets, the modifying agent, and the silane coupling agent are mixed uniformly in a high-speed mixer, and then melted, extruded, and pelletized in a second twin-screw extruder. The heating zone temperature of the second twin-screw extruder ranges from 170°C to 200°C, and the heating zone temperature increases uniformly. The speed of the second screw extruder is 280 rpm to 310 rpm.

[0045] It should be noted that the high-speed mixing and dispersing machine adopts various forms of speed regulation, including stepless speed regulation, electromagnetic speed regulation, frequency conversion speed regulation and explosion-proof frequency conversion speed regulation. The stepless speed regulation function can fully meet the different process requirements of each process, and different speeds can be selected according to different process stages.

[0046] S300, mixing the dried preliminarily processed pellets with azodicarbonamide and a cell regulator, and performing melting and foaming extrusion to obtain a polystyrene foam material.

[0047] Specifically, the dried pre-processed pellets are mixed with azodicarbonamide and a cell regulator in a high-speed mixer. After the raw materials are evenly mixed in the high-speed mixer, they are melted and foamed and extruded through a single-screw foaming extruder. The foaming rate of the polystyrene foam material is 2.1 to 2.8.

[0048] Among them, azodicarbonamide is a commonly used foaming agent in industry, used in the production of yoga mats, rubber shoe soles, and other products to increase their elasticity. Foaming agents are substances that can create microporous structures in rubber and plastics, either liquid or plastic, within a certain viscosity range. Physical foaming agents create pores by changing their physical state within a certain temperature range, while chemical foaming agents produce one or more gases during the foaming process, which can cause polymers to foam.

[0049] In addition, the use of a cell regulator can promote the gelation of polystyrene foam materials, increase the thermal strength and elongation of the melt, improve the surface quality of the product, and stabilize the fine cells formed by the foaming agent, preventing the cell walls from breaking and penetrating each other to form large pores. Therefore, the resulting foam has not only low density but also good strength.

[0050] S400, cooling and shaping the polystyrene foam material, and performing traction cutting to obtain a finished product.

[0051] Specifically, after the polystyrene foam material cools and sets, the foam material becomes more stable and strong. The polystyrene foam material board can then be pulled and cut according to the size specifications.

[0052] After obtaining the polystyrene foam material, a toughness test is performed. The test objects are the polystyrene foam material and the recycled polystyrene composite material (the foam material prepared in this application), and the test parameters are tensile strength and impact strength.

[0053] Test results showed that the tensile strength of polystyrene foam was 32.68 MPa, while that of recycled polystyrene foam was 44.67 MPa, 43.95 MPa, and 44.26 MPa, respectively, representing a 37.5% increase. The impact strength of polystyrene foam was 10.16 MPa, while the tensile strength of recycled polystyrene foam was 11.56 kJ / m2, 12.65 kJ / m2, and 10.87 kJ / m2, respectively, representing a 20% increase.

[0054] Compared with the prior art, the present invention has at least the following beneficial effects:

[0055] The present invention uses styrene-butadiene-styrene block copolymer as a modifier, and a small amount of SBS is blended with polystyrene to significantly improve the low-temperature performance and impact strength of the product. SBS as an adhesive has the characteristics of high solid content, fast drying, and low-temperature resistance. At the same time, combined with a silane coupling agent, it can greatly improve the tensile properties and impact resistance of the polypropylene foam material.

[0056] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A recycled polystyrene foam material, characterized in that: In parts by weight, it includes:

2. The recycled polystyrene foam material and preparation method according to claim 1, characterized in that: The modification aid is styrene-butadiene-styrene block copolymer.

3. The recycled polystyrene foam material and preparation method according to claim 1, characterized in that: The content of butadiene monomer in the styrene-butadiene-styrene block copolymer is 60% to 80%.

4. The recycled polystyrene foam material and preparation method as claimed in claim 1, characterized in that: It also includes a cell regulator, and the weight portion of the cell regulator is 1 to 2.5 parts.

5. A method for preparing a recycled polystyrene foam material, characterized in that: include: Weigh an appropriate amount of polystyrene, melt, extrude and granulate, obtain granules and dry them; The dried pellets, the modification aid and the silane coupling agent are mixed evenly, and melted, extruded and granulated to obtain preliminary processed pellets and dry them; The dried preliminarily processed pellets are mixed with azodicarbonamide and a cell regulator, and melted and foamed to obtain a polystyrene foam material; The polystyrene foam material is cooled and shaped, and then pulled and cut to obtain the finished product.

6. The method for preparing a recycled polystyrene foam material according to claim 5, characterized in that: In the pellet preparation process, melting, extrusion and pelletization are performed by the first twin-screw extruder.

7. The method for preparing a recycled polystyrene foam material according to claim 6, wherein: The temperature range of the heating zone of the first twin-screw extruder is 180° C. to 210° C., and the temperature of the heating zone increases evenly. The rotation speed of the first twin-screw extruder is 290 r / min to 310 r / min.

8. The method for preparing a recycled polystyrene foam material according to claim 5, characterized in that: During the preparation of the preliminary processed pellets, the dried pellets, the modifying aid and the silane coupling agent are uniformly mixed by a high-speed mixer, and then melted, extruded and granulated by a second twin-screw extruder.

9. The method for preparing a recycled polystyrene foam material according to claim 8, characterized in that: The temperature range of the heating zone of the second twin-screw extruder is 170° C. to 200° C., and the temperature of the heating zone rises evenly. The rotation speed of the second screw extruder is 280 r / min to 310 r / min.

10. The method for preparing a recycled polystyrene foam material according to claim 5, characterized in that: The foaming rate of the polystyrene foam material is 2.1 to 2.8.

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