TWM679773U - Plastic board - Google Patents

Abstract

A plastic board includes a first side, a second side, a bottom surface, and a top surface. The first side has a first groove, and the second side is opposite to the first side. The top surface is opposite to the bottom surface, and the bottom surface and the top surface are between the first side and the second side. The material of the plastic board includes a thermoplastic composition, and the thermoplastic composition includes: (a) recycled polystyrene; (b) a styrene-conjugated diene block copolymer; (c) an amino-modified styrene-conjugated diene block copolymer; and (d) an anhydride-modified polyolefin. In the thermoplastic composition, the component (a) is 70 to 100 parts by weight, the component (b) is 1 to 10 parts by weight, the component (c) is 0.5 to 5 parts by weight, the component (d) is 1 to 10 parts by weight, and the parts by weight of the component (c) is less than the parts by weight of the component (b) and is also less than the parts by weight of the component (d).

Description

plastic sheet

This case concerns a plastic sheet containing recycled polystyrene.

In recent years, with the development of human economic activities, the use of plastic products has increased dramatically, leading to increasingly serious marine environmental pollution problems. Among them, the problem of marine plastic debris is particularly prominent. According to a study published in the journal Science by Jambeck et al. (Jambeck et al., Science 347: 768-771, 2015), approximately 8 million tons of plastic debris flow into the ocean every year. This marine plastic debris not only harms the marine ecosystem, causing marine life to ingest it or become entangled and injured, but also, through bioaccumulation in the food chain, may ultimately endanger human health.

Polystyrene (PS) is one of the main pollutants in marine plastic waste. To reduce pollution, technologies for recycling PS (such as solvent methods) have been developed. However, recycled PS, due to long-term exposure to seawater, ultraviolet radiation, and various pollutants, undergoes degradation phenomena such as molecular chain breakage and oxidation. Therefore, recycled PS has lower mechanical properties than newly manufactured polystyrene in terms of impact resistance, tensile strength, flowability, aging resistance, and hardness, making it unsuitable or impossible for further remanufacturing. Consequently, the utilization rate of recycled polystyrene (rPS) remains low.

For example, while plastics can be used in some building materials (such as flooring), these materials are often used outdoors and exposed to high-strength environments such as intense sunlight, strong winds, and heavy rain, which accelerate plastic degradation. Therefore, if the plastic itself is not strong enough, the building material will easily crack or break, shortening the product's lifespan and posing a safety hazard to users. Consequently, rPS is generally not directly used in building materials, thus reducing its usage rate.

In view of the aforementioned problems, one embodiment of this invention provides a plastic sheet that, compared to sheets made solely of rPS, exhibits superior properties in at least one of tensile strength, elongation, flexural strength, and impact strength, thereby improving the practicality of the plastic sheet and indirectly increasing the utilization rate of rPS. Specifically, the plastic sheet of this embodiment includes a first side, a second side, a bottom surface, and a top surface. The second side is opposite to the first side. The top surface is opposite to the bottom surface, and the bottom and top surfaces are located between the first and second sides. The material of the plastic sheet comprises a thermoplastic composition including: (a) recycled polystyrene; (b) styrene-conjugated diene block copolymer; (c) amino-modified styrene-conjugated diene block copolymer; and (d) anhydride-modified polyolefin. In the thermoplastic composition, component (a) is present in quantities of 70 to 100 parts by weight, component (b) in quantities of 1 to 10 parts by weight, component (c) in quantities of 0.5 to 5 parts by weight, and component (d) in quantities of 1 to 10 parts by weight, wherein the weight of component (c) is less than the weight of both component (b) and component (d).

The aforementioned thermoplastic compositions improve their properties by using styrene-conjugated diene block copolymers and polyolefin compounds as toughening agents in rPS. It is worth noting that, generally, polyolefins and PS have significant differences in molecular structure and polarity, resulting in poor compatibility and the formation of an interface between them. This prevents the effective transfer of stress between the different phases during stress generation, thus limiting the toughening effect of polyolefins on PS. However, since one embodiment of this case uses an anhydride-modified polyolefin in its thermoplastic composition, and some of the styrene-conjugated diene block copolymer is replaced with anamine-modified styrene-conjugated diene block copolymer, the anhydride groups of the polyolefin can react with the amine groups to form chemical bonds during the processing of the thermoplastic composition. This chemically couples the polyolefin with other components in the composition, increases the miscibility between the polyolefin and other components, and makes the overall phase structure of the composition more stable. Therefore, according to one or more embodiments of this invention, the components in the thermoplastic composition can better exert their effects, ultimately effectively improving at least one of the properties of the composition, such as tensile strength, elongation, flexural strength, or impact strength. Accordingly, the plastic sheet of one embodiment of this invention can be applied to more situations, thereby indirectly increasing the utilization rate of rPS.

The following provides a detailed description of the plastic sheet described in this case. The following description provides many different embodiments, which are for illustrative purposes only and not intended to limit the scope of this case. Furthermore, the phrases "in one embodiment" or "in one embodiment" appearing in different places in the specification do not necessarily refer to the same embodiment. Unless otherwise stated or clearly conflicted herein, the features and structures described herein may be combined in one or more embodiments by any suitable method.

In this specification, the phrase "from one value to another" is a summary representation that avoids listing all values within that range in the specification. Therefore, unless otherwise stated or clearly contrary to reasonable common knowledge in the art to which this application pertains, a particular range of values described in this specification is equivalent to disclosing any value within that range and the smaller range defined by that value (including its significant digits and the next significant digit), as if the arbitrary value and the smaller range were explicitly stated in the specification. For example, when the specification states "1 to 10," it is equivalent to disclosing the ranges of "3 to 5" and "2.5 to 6.8," regardless of whether other values are listed in the specification.

Unless otherwise specified, the terms "contains" and "includes" used in this article are open-ended terms and should be interpreted as "containing but not limited to...".

In this document, unless otherwise indicated, the word "or" is used to refer to a non-exclusive "or", such that "A or B" includes the cases of "A but not B (or A exists but B does not exist)", "B but not A (or B exists but A does not exist)" and "A and B (both A and B exist)".

In this specification, the terms "first," "second," etc., are used as adjectives only to distinguish the nouns they modify from one another, and not to describe any specific relationship between the nouns. Therefore, it should be understood that the use of terms such as "first groove" and "second groove" does not imply any specific order, type, hierarchy, or ranking between these two grooves.

Please refer to Figures 1 and 2. Figure 1 is a perspective view of an embodiment of the plastic sheet 1 of this invention. Figure 2 is a cross-sectional view of the plastic sheet 1 shown in Figure 1 along section line AA'. The plastic sheet 1 includes a first side 11, a second side 12, a bottom surface 13, and a top surface 14. The second side 12 is opposite to the first side 11. The top surface 14 is opposite to the bottom surface 13, and the bottom surface 13 and the top surface 14 are located between the first side 11 and the second side 12. The material of the plastic sheet 1 includes a thermoplastic composition; in some embodiments, the plastic sheet 1 may be made solely of said thermoplastic composition. The thermoplastic composition comprises: (a) recycled polystyrene, (b) styrene-conjugated diene block copolymer, (c) amino-modified styrene-conjugated diene block copolymer, and (d) anhydride-modified polyolefin.

(a) Recycled polystyrene

"Recycled polystyrene" refers to polystyrene resin obtained from post-consumer waste or post-industrial waste through mechanical or chemical recycling processes. For example, recycled polystyrene can be polystyrene resin obtained after collection, crushing, washing, sorting, and processing.

In some embodiments, the recycled polystyrene has a tensile strength (as determined by ASTM D638) of less than 375 kgf/ ^cm² , an impact strength (as determined by ASTM D256) of less than 900 J/ ^m² , and an elongation (as determined by the <Elongation Test> method described in the following embodiments) of less than 3%.

In some embodiments, the recycled polystyrene content in the thermoplastic composition may be greater than or equal to 60 wt%, for example, 70 wt%, 80 wt%, or 85 wt%. In some embodiments, the upper limit of the recycled polystyrene content in the thermoplastic composition is 99 wt%, for example, 97 wt%, 95 wt%, or 90 wt%.

[(b) Styrene-conjugated diene block copolymer]

"(b) Styrene-conjugated diene block copolymer" refers to a polymer having styrene blocks and blocks based on a conjugated diene compound (conjugated diene monomer).

The aforementioned "conjugated diene compound" refers to a diene compound having at least one pair of conjugated double bonds. Specific examples of such "conjugated diene compounds" include 1,3-butadiene, 2-methyl-1,3-butadiene (or isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, and 1,3-hexadiene. In some embodiments, it may be 1,3-butadiene and 2-methyl-1,3-butadiene. These conjugated diene compounds may be used alone or in combination.

Furthermore, in this case, "(b) styrene-conylated diene block copolymer" can be a "hydrogenated conylated diene polymer" or a "non-hydrogenated conylated diene polymer". Examples of the "hydrogenated conylated diene polymer" include block copolymers based on the hydrogenation of all or part of the conylated compound blocks, such as hydrogenated styrene-isoprene-styrene copolymer (also known as styrene-ethylene/propylene-styrene block copolymer, SEPS), hydrogenated styrene-butadiene-styrene block copolymer (also known as styrene-ethylene/butene-styrene block copolymer, SEBS), styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), and hydrogenated styrene-butadiene block copolymer. Examples of "unhydrogenated conjugated diene polymers" include block copolymers based on conjugated compound blocks that are not hydrogenated, such as styrene-isoprene-styrene block copolymers (also known as SIS), styrene-butadiene-styrene block copolymers (also known as SBS), styrene-butadiene-butene-styrene block copolymers (also known as SBBS), and styrene-butadiene diblock copolymers. In some embodiments, "(b) styrene-conjugated diene block copolymers" are "hydrogenated conjugated diene polymers," such as SEBS, which have relatively fewer double bonds and thus better antioxidant properties, thermal stability, and low photodegradability. More preferably, SEBS has a styrene content of 10% to 40% by weight, which exhibits a better balance between toughness and rigidity. In some other embodiments, "(b) styrene-conjugated diene block copolymer" may have more than one component.

In some embodiments, the weight-average molecular weight (Mw) of the "styrene-conjugated diene block copolymer" is 1.0 × ^10⁴ to 5.0 × ^10⁵ , which is determined by establishing a calibration curve using polystyrene standards using gel permeation chromatography (GPC). In some embodiments, when "(b) styrene-conjugated diene block copolymer" has more than one component, the weight-average molecular weight of each component is within the aforementioned range.

As a "styrene-conjugated diene block copolymer", commercially available products include Kraton 1650 (SEBS) manufactured by Kraton polymers U.S. LLC and SEPTON 8000 series (SEBS) manufactured by Kuraray Co., Ltd.

Component (b), "styrene-conjugated diene block copolymer," can be used as a toughening agent for polystyrene. Specifically, the "styrene-conjugated diene block copolymer" comprises styrene hard segments and rubber soft segments (i.e., conjugated diene blocks), wherein the styrene blocks have good compatibility with the polystyrene matrix, ensuring the uniform dispersion of component (b) in the matrix. The rubber blocks, when subjected to external forces, can undergo elastic deformation, effectively absorbing and dispersing stress concentration, and preventing rapid crack propagation. Therefore, component (b) can improve the toughness of polystyrene and thus act as a toughening agent for polystyrene.

[(c) Amine-modified styrene-conjugated diene block copolymer]

"(c) Amine-modified styrene-conjugated diene block copolymer" is based on the aforementioned "(b) styrene-conjugated diene block copolymer" and is further modified with amine groups. It should be noted that the components belonging to "(c) Amine-modified styrene-conjugated diene block copolymer" in this case do not belong to "(b) styrene-conjugated diene block copolymer".

Regarding the method for manufacturing "(c) amine-modified styrene-conjugated diene block copolymer", it can be achieved by first synthesizing a styrene-conjugated diene block copolymer and then introducing amine groups through a modification reaction, or by directly copolymerizing amine-containing monomers to produce the "amine-modified styrene-conjugated diene block copolymer".

As for "(c) amino-modified styrene-conjugated diene block copolymer", it may be selected from at least one of the following groups: amino-modified styrene-butadiene-styrene block copolymer (SBS), amino-modified styrene-isoprene-styrene block copolymer (SIS), amino-modified styrene-ethylene/butene-styrene block copolymer (SEBS), amino-modified styrene-ethylene/propylene-styrene block copolymer (SEPS), amino-modified styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), amino-modified styrene-butadiene-butene-styrene block copolymer (SBBS), amino-modified styrene-butadiene diblock copolymer, and amino-modified hydrogenated styrene-butadiene block copolymer. In some embodiments, "(c) amino-modified styrene-conjugated diene block copolymer" is amino-modified SEBS.

In "(c) Amine-modified styrene-conjugated diene block copolymer", there are no special restrictions on the location of the amine group. For example, the amine group can be located at the end, side chain, or main chain of the styrene-conjugated diene block copolymer.

In some embodiments, the weight-average molecular weight (Mw) of "(c) amino-modified styrene-conjugated diene block copolymer" is 1.0 × ^10⁴ to 5.0 × ^10⁵ , which is determined by gel osmosis chromatography (GPC) using a calibration curve established with polystyrene standards. In some embodiments, when "(c) amino-modified styrene-conjugated diene block copolymer" contains multiple components, the weight-average molecular weight of each component may be within the aforementioned range.

In one embodiment, if the total weight of "(c) amine-modified styrene-conjugated diene block copolymer" is 100 wt%, the content of amine functional groups can be from 0.1 wt% to 15 wt%, from 0.5 wt% to 10 wt%, or from 0.5 wt% to 5 wt%. The aforementioned content of amine functional groups can be determined by detection methods known in the art (e.g., but not limited to acid-base titration).

As for "(c) amine-modified styrene-conjugated diene block copolymer", commercially available products that can be used include Tuftec MP10 (amine-modified SEBS) manufactured by Asahi Kasei Corporation and DYNARON 8630P (amine-modified SEBS) manufactured by JSR Corporation.

[(d) Anhydride-modified polyolefins]

"(d) Anhydride-modified polyolefins" refers to modified polymers in which anhydride groups are grafted or copolymerized onto the polyolefin backbone.

The aforementioned "polyolefin" refers to a polymer having an olefin-based structural unit, and it can be an olefin homopolymer or a copolymer obtained by copolymerizing a copolymerizable compound with an olefin. For example, the olefin can be ethylene or an α-olefin having 3 to 20 carbon atoms. In some embodiments, the "polyolefin" is ethylene or an α-olefin having 3 to 12 carbon atoms.

Specifically, the polyolefin may be selected from polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-octene copolymer, or combinations thereof. Anhydride groups may include maleic anhydride, succinic anhydride, or phthalic anhydride. Maleic anhydride is particularly preferred due to its superior reactivity.

It should be noted that compounds belonging to "(b) styrene-conjugated diene block copolymers" or "(c) amine-modified styrene-conjugated diene block copolymers" do not belong to "(d) anhydride-modified polyolefins".

Regarding the method for manufacturing "(d) anhydride-modified polyolefin", it can be achieved by synthesizing a polyolefin and then introducing an anhydride group to produce the anhydride functionalized polyolefin, or by using a monomer containing an anhydride group to perform a copolymerization reaction to obtain the desired anhydride-modified polyolefin.

In "(d) Anhydride-modified polyolefins", there are no special restrictions on the location of the anhydride functional group. For example, the anhydride functional group can be located at the end, side, or main chain of the polyolefin.

In some embodiments, the weight-average molecular weight (Mw) of the "(d) anhydride-modified polyolefin" is 2.0 × ^10⁴ to 2.0 × ^10⁵ , which is determined by gel osmosis chromatography (GPC) using a calibration curve established with polystyrene standards. When the "(d) anhydride-modified polyolefin" contains multiple components, the weight-average molecular weight of each component is within the aforementioned range.

In some embodiments, if the total weight of "(d) anhydride-modified polyolefins" is 100 wt%, the anhydride functional group content can be from 0.1 wt% to 8 wt%, from 0.5 wt% to 5 wt%, or from 1.0 wt% to 4 wt%. The aforementioned anhydride functional group content can be determined by detection methods known in the art (e.g., but not limited to acid-base titration).

As "(d) anhydride-modified polyolefins", commercially available products that can be used include Fusabond E226 (maleic anhydride-modified polyethylene) manufactured by Dow Global Technologies LLC.

Component (d) "anhydride-modified polyolefin" also serves as a toughening agent for polystyrene. Specifically, since the polyolefin phase has a relatively lower elastic modulus than polystyrene, under external force, the polyolefin phase acts as a stress concentration buffer zone and preferentially undergoes plastic deformation, thereby enhancing the energy absorption capacity of the material.

In the thermoplastic composition of this case, "(a) recycled polystyrene" comprises 70 to 100 parts by weight, "(b) styrene-conjugated diene block copolymer" comprises 1 to 10 parts by weight, "(c) amino-modified styrene-conjugated diene block copolymer" comprises 0.5 to 5 parts by weight, and "(d) anhydride-modified polyolefin" comprises 1 to 10 parts by weight. The weight of "(c) amino-modified styrene-conjugated diene block copolymer" is less than the weight of "(b) styrene-conjugated diene block copolymer" and also less than the weight of "(d) anhydride-modified polyolefin". In detail, the creators found that while "(c) amino-modified styrene-conjugated diene block copolymer" can promote interfacial adhesion between components, it mainly provides basic toughening effect. The "(b) styrene-conjugated diene block copolymer" is still the one that improves impact strength. Therefore, "(b) styrene-conjugated diene block copolymer" must still be present. Furthermore, the creators found that although "(c) amino-modified styrene-conjugated diene block copolymer" has a toughening effect, when its content is too high, in addition to the increase in toughening effect being insignificant, it will also lead to excessively high melt viscosity of the thermoplastic composition, affecting processability. Accordingly, the content of "(c) amine-modified styrene-conjugated diene block copolymer" should be less than the content of "(b) styrene-conjugated diene block copolymer" and also less than the content of "(d) anhydride-modified polyolefin".

In some embodiments, the thermoplastic composition comprises (a) 80 to 97 parts by weight, (b) 1 to 4 parts by weight, (c) 0.5 to 2 parts by weight, and (d) 1.5 to 5 parts by weight. These proportions allow the thermoplastic composition to achieve a better balance between toughness and rigidity.

In summary, the thermoplastic composition of this case improves the properties of the composition by using "(b) styrene-conjugated diene block copolymer" and polyolefin compounds as toughening agents in rPS. It is worth noting that, generally, polyolefins and PS have significant differences in molecular structure and polarity, resulting in poor compatibility and the formation of an interface between them. This prevents the effective transfer of stress between different phases when stress occurs, thus limiting the toughening effect of polyolefins on PS. However, since the thermoplastic composition of this case uses "(d) anhydride-modified polyolefins" and replaces part of the styrene-conjugated diene block copolymer with "(c) amine-modified styrene-conjugated diene block copolymers", the anhydride groups of the polyolefins can react with the amine groups to form chemical bonds during the processing of the thermoplastic composition, thereby chemically coupling the polyolefins with other components in the composition, increasing the miscibility between the polyolefins and other components, and making the overall phase structure of the composition more stable. Therefore, the components in thermoplastic compositions can better exert their effects, and ultimately effectively improve at least one of the mechanical properties of the composition, such as tensile strength, elongation, flexural strength and impact strength.

In some embodiments, the thermoplastic composition may also include other processing aids such as lubricants, antistatic agents, plasticizers, stabilizers, and antioxidants. Examples of lubricants may include, but are not limited to, acetylated distearate, erucic acid, dioctyl phthalate, or organosilicone oils. Examples of plasticizers may include, but are not limited to, epoxidized soybean oil or naphthenic rubber oil. Examples of stabilizers may include, but are not limited to, stearates. Antioxidants may include, but are not limited to, hindered phenolic, thioester, or phosphite antioxidants.

In some embodiments, if 100 parts by weight of the recycled polystyrene in (a) is taken as the amount of processing aids, the thermoplastic composition may contain 0.1 to 1.0 parts by weight. In some embodiments, the content of processing aids in the polystyrene composition may be in the range of 0.1 to 0.5 parts by weight or 0.1 to 0.3 parts by weight.

[Structure of Plastic Sheet 1]

As previously described, the plastic sheet 1 includes a first side 11, a second side 12, a bottom surface 13, and a top surface 14. In some embodiments, to facilitate easier splicing of the plastic sheets 1 for installation on surfaces such as flooring, the plastic sheet 1 also has a splicing structure. For example, as shown in Figures 1 and 2, the first side 11 of the plastic sheet 1 has a first groove 111, and the second side 12 has a protrusion 121. The cross-sectional shape of the protrusion 121 matches the cross-sectional shape of the first groove 111 so that the protrusion 121 can be embedded in the first groove 111. Based on this, multiple plastic sheets 1 can be spliced together by the protrusion 121 on its second side 12 engaging with the first groove 111 of the first side 11 of another plastic sheet 1.

In some embodiments, the two plastic sheets 1 are connected by an additional snap fastener 2. For example, please refer to Figure 3. Figure 3 is a schematic cross-sectional view drawn according to another embodiment of the plastic sheet 1 of this invention (the snap fastener 2 is not shown in Figure 3, but will be explained further later). As shown in Figure 3, the first side 11 of the plastic sheet 1 has a first groove 111, and the second side 12 has a second groove 122. Accordingly, one side of the snap fastener 2 can clamp a portion of the plastic sheet 1, while the other side of the snap fastener 2 clamps a portion of the other plastic sheet 1, thereby connecting the two plastic sheets 1.

For example, please refer to Figures 4 and 5. Figure 4 is a three-dimensional schematic diagram of one embodiment of the fastener 2. Figure 5 is a three-dimensional schematic diagram of the fastener 2 shown in Figure 4 fastened to the plastic plate 1 shown in Figure 3. The fastener 2 includes a rectangular strip-shaped fastener body 21 located in the center. In the extending direction of the fastener body 21 (which is also the extending direction of the first groove 111), a base plate 22 and a top pressure plate 23 are provided protruding from the left and right sides of the fastener body 21. In this embodiment, the base plate 22 and the top pressure plate 23 are arranged crosswise on the left and right sides of the fastener body 21. That is, if a top pressure plate 23 is provided on the left side of the fastener body 21, a bottom plate 22 is provided at the corresponding position on the right side of the fastener body 21; if a bottom plate 22 is provided on the left side of the fastener body 21, a top pressure plate 23 is provided at the corresponding position on the right side of the fastener body 21.

With the aforementioned structure, the base plate 22 and the top pressure plate 23 can form clamping grooves 24 on the left and right sides of the fastener body 21, thereby accommodating a portion of the plastic sheet 1. For example, as shown in FIG. 5, the top pressure plate 23 on one side of the fastener 2 can be inserted into the first groove 111 of the plastic sheet 1, and the base plate 22 on that side of the fastener 2 contacts the bottom surface 13 of the plastic sheet 1. The top pressure plate 23 on the other side of the fastener 2 can then be inserted into the first groove 111 or the second groove 122 of another plastic sheet 1, and the base plate 22 on that other side of the fastener 2 contacts the bottom surface 13 or the top surface 14 of the other plastic sheet 1. Accordingly, the clamping grooves 24 on both sides of the fastener 2 will respectively accommodate a portion of the plastic sheet 1 and a portion of another plastic sheet 1, thereby connecting the two plastic sheets 1.

Please refer back to Figure 4. In some embodiments, the base plate 22 of the snap fastener 2 has an opening 221. In some cases, if the user wishes to further increase the connection strength between the plastic plate 1 and the snap fastener 2 or between the plastic plate 1 and other components after connecting the plastic plate 1 via the snap fastener 2, a fastener such as a screw can be inserted through the plastic plate 1 into the opening 221 of the base plate 22 to lock it with other components (not shown in Figure 4 or Figure 5). In other embodiments, the cross section (perpendicular to the fastener body 21 and the base plate 22) of the pressure plate 23 is V-shaped, which can further reduce the height of the clamping groove 24, thereby increasing the clamping force between the clamping groove 24 and the plastic plate 1.

In some embodiments, as shown in Figure 3, the shortest distances L1 between the first groove 111 and the bottom surface 13, L2 between the first groove 111 and the top surface 14, L3 between the second groove 122 and the bottom surface 13, and L4 between the second groove 122 and the top surface 14 are all the same. With the structure described in this paragraph, the clamping grooves 24 on both sides of the buckle 2 can be designed to have the same height, without needing to distinguish between left and right. At the same time, when two plastic plates 1 are connected by the buckle 2, it is not necessary to distinguish between the top surface 14 or the bottom surface 13 of each plastic plate 1; assembly can be performed on either side.

[Manufacturing method of plastic sheet 1]

The plastic sheet 1 of this case can be manufactured by, for example, the following steps: (1) forming a thermoplastic plastic composition; (2) melting and mixing the thermoplastic plastic composition; and (3) molding.

Regarding the step "(1) forming a thermoplastic composition", the required amounts of (a) recycled polystyrene, (b) styrene-conjugated diene block copolymer, (c) amino-modified styrene-conjugated diene block copolymer, (d) anhydride-modified polyolefin, and processing aids (if any) can be directly mixed to form the thermoplastic composition. Alternatively, some of the components can be mixed first, and then mixed with the remaining components to obtain the thermoplastic composition.

For example, a portion of (a) recycled polystyrene and all of (b) styrene-conjugated diene block copolymer, (c) amino-modified styrene-conjugated diene block copolymer, and (d) anhydride-modified polyolefin can be mixed using a twin-screw extruder and granulated using a granulator to obtain a reinforcing and toughening masterbatch. This reinforcing and toughening masterbatch is then mixed with the remaining amount of (a) recycled polystyrene to obtain the aforementioned thermoplastic composition.

Regarding the step "(2) Melt-mixing the thermoplastic composition", it can be performed by introducing the thermoplastic composition into a heated extruder containing a screw. The extruder may be any of a single-screw extruder, a twin-screw extruder, or a planetary mixing extruder. The applied temperature should be sufficient to melt the thermoplastic composition but not to cause thermal degradation. In some cases, the melt-mixing step may be performed at a temperature of approximately 150 to 300°C and a screw speed of approximately 100 to 300 rpm. In some cases, to facilitate subsequent processing, the thermoplastic plastic composition after melt mixing can be granulated into granules by a granulator before proceeding with the subsequent (3) molding process.

Regarding the "(3) molding process" step, the plastic sheet 1 can be formed by feeding the molten thermoplastic composition into a molding machine and forming it by extrusion molding or injection molding.

[Preparation and Property Testing of Thermoplastic Compositions]

The features and advantages of the thermoplastic composition of this application will be described more specifically below through examples of composition preparation and comparative examples. Furthermore, although the following examples of composition preparation are described herein, some details may be appropriately modified without departing from the scope claimed in this claim. That is, the examples of composition preparation described below should not be interpreted restrictively on this application.

<Preparation of Reinforced and Toughened Masterbatch>

Weigh out 65 parts by weight of recycled polystyrene (purchased from Yitong Plastics Co., Ltd., model REPS-475, as (a) recycled polystyrene), 13 parts by weight of Kraton 1650 (as (b) styrene-conjugated diene block copolymer), 6 parts by weight of Tuftec MP10 (as (c) amino-modified styrene-conjugated diene block copolymer) and 16 parts by weight of Fusabond E226 (as (d) anhydride-modified polyolefin).

Next, using a twin-screw extruder (model ZSK25, L/D=40), the aforementioned components were fed into the extruder for mixing at a temperature of 160~220℃ and a screw speed of 200 rpm. Then, the mixture was granulated by a granulator (model GZML-110L-150) to obtain reinforced and toughened masterbatch.

<Examples 1 to 3 of the preparation of thermoplastic components>

According to Table 1, the corresponding weight parts of reinforcing and toughening masterbatch and the corresponding weight parts of recycled polystyrene (purchased from Yitong Plastics Co., Ltd., model REPS-475. As (a) recycled polystyrene) of each thermoplastic composition preparation example were fed into a twin-screw extruder (model ZSK25, L/D=40) and mixed at a temperature of 160~220℃ and a screw speed of 200 rpm. Then, the mixture was granulated by a granulator (model GZML-110L-150) to obtain the corresponding thermoplastic composition preparation example granules.

Table 1 Enhanced toughness masterbatch Recycled polystyrene Preparation Example 1 10 90 Preparation Example 2 20 80 Preparation Example 3 30 70

The weight ratios of the components in the preparation examples obtained by the aforementioned method are shown in Table 2 below.

Table 2 Component (a) Component (b) Component (c) Component (d) Preparation Example 1 96.5 1.3 0.6 1.6 Preparation Example 2 93.0 2.6 1.2 3.2 Preparation Example 3 89.5 3.9 1.8 4.8

＜Comparative example＞

The aforementioned commercially available recycled polystyrene was used as a comparative example.

<Tensile Strength Test>

In accordance with ASTM D638, using the aforementioned preparation examples and comparative examples, dumbbell-shaped specimens (150 mm × 12.7 mm × 3.2 mm in size) were produced by injection molding machine (Nissei Resin Kogyo Co., Ltd., model: NEX50-IV). The tensile strength (the force required to break when the local cross-section is reduced) of each specimen was measured using a universal test machine (Shimadzu Corporation, model: Shimadzu AG-1).

<Elongation Test>

Using the aforementioned preparation examples and comparative examples, rectangular specimens (30 mm × 10 mm × 0.1 mm) were fabricated using an injection molding machine (Nissei Resin Kogyo Co., Ltd., model: NEX50-IV). The elongation was measured using a viscoelasticity measuring apparatus (TA Instruments, model: ARES G2) at 25°C and a fixed Hencky strain mode, using an extensional viscosity fixture at a shear rate of 0.1 ^s⁻¹ . The elongation is defined as the ratio of the difference between the specimen length _L₁ at cracking and the initial specimen length _L₀ (= _L₁ - _L₀ ) to _L₀ (= ( _L₁ - _L₀ ) / _L₀ × 100 (%)).

<Bending Strength Test>

According to ASTM D790 standard, using a three-point bending test fixture (indenter radius 10 mm, fulcrum radius 10 mm), with the support span set at 100 mm, the bending strength (maximum bending stress at specimen failure) was measured under test conditions of a crosshead speed of 5.3 mm/min. The testing machine was an Instron 4201 universal testing machine.

<Impact Strength Test>

According to ASTM D256, rectangular specimens (64.0 mm × 12.7 mm × 3.2 mm) were fabricated using the aforementioned preparation examples and comparative examples via injection molding machine (Nissei Resin Kogyo Co., Ltd., model: NEX50-IV). The impact strength was measured using an Izod impact testing machine (Testing Machines Inc., model: NO. 43-01) at 23°C and 50% relative humidity. Impact strength = destructive energy / cross-sectional area at the notch of the specimen. Specifically, the specimen was impacted by a pendulum with a specific energy capacity and drop height during the test. Therefore, when the pendulum strikes the sample, some kinetic energy is released to the sample, so the pendulum cannot return to its initial falling height after the impact. Based on this, the energy required to destroy the sample (the aforementioned "destruction energy") can be deduced from the difference between the measured falling height and the rising height.

The results of the above experiments are summarized in Table 3 below. Tensile strength (kgf/ ^cm² ) Elongation (%) Bending strength (kgf/ ^cm² ) Impact intensity (J/ ^m² ) Preparation Example 1 393.0 5.9 555.0 2067.0 Preparation Example 2 382.3 8.4 528.7 2490.0 Preparation Example 3 360.7 6.7 505.7 3038.0 Comparative example (i.e., component only (a)) 372.4 0.01 550.6 895.7

As shown in Table 3, regarding elongation, the comparative example has an elongation of only 0.01%, indicating that recycled polystyrene is almost non-tough. In contrast, the elongations of Preparation Examples 1 to 3 of this invention reach 5.9%, 8.4%, and 6.7%, respectively, showing a significant increase. Furthermore, regarding impact strength, the comparative example has an impact strength of only 895.7 J/m², while Preparation Examples 1 to 3 have impact strengths of 2067.0, 2490.0, and 3038.0 J/m², respectively, representing an increase of 2.3 to 3.4 times. Therefore, it is evident that the composition of the thermoplastic components in one or more of the preparation examples of this invention has a significant synergistic effect in absorbing impact energy, effectively improving the material's resistance to breakage. In terms of tensile strength and flexural strength, even in Preparation Example 3, the properties are maintained close to those of recycled polystyrene, maintaining a certain degree of rigidity in the material as a whole. Furthermore, in Preparation Examples 1 and 2, the tensile strength and flexural strength of the components can even be slightly improved, resulting in better overall material properties.

Based on the results of the above tests, it can be seen that the thermoplastic composition of this invention can significantly improve the elongation and impact strength of the material without significantly reducing tensile strength and flexural strength, and significantly improve toughness and impact resistance, thereby overcoming the shortcomings of recycled polystyrene. Accordingly, plastic sheets made using the aforementioned recycled polystyrene can be applied to more scenarios, indirectly increasing the utilization rate of recycled polystyrene.

1: Plastic sheet; 11: First side; 111: First groove; 12: Second side; 121: Raised strip; 122: Second groove; 13: Bottom surface; 14: Top surface; 2: Fastener; 21: Fastener body; 22: Base plate; 221: Opening; 23: Top pressure plate; 24: Clamping groove; L1, L2, L3, L4: Distance

Figure 1 is a perspective view of one embodiment of the plastic sheet according to this invention. Figure 2 is a cross-sectional view of the plastic sheet shown in Figure 1 along section line AA'. Figure 3 is a cross-sectional view of another embodiment of the plastic sheet according to this invention. Figure 4 is a perspective view of one type of fastener. Figure 5 is a perspective view of the fastener shown in Figure 4 fastened to the plastic sheet shown in Figure 3.

1: Plastic sheet

11: First side

111: First Groove

12: Second side

121: convex strip

13: Bottom surface

14: Top surface

Claims (11)

A plastic sheet comprising: a first side; a second side opposite to the first side; a bottom surface; and a top surface opposite to the bottom surface, the bottom surface and the top surface being located between the first side and the second side; wherein the material of the plastic sheet comprises a thermoplastic composition comprising: (a) recycled polystyrene; (b) a styrene-conjugated diene block copolymer; (c) an amino-modified styrene-conjugated diene block copolymer; and (d) an anhydride-modified polyolefin; In the thermoplastic composition, component (a) is 70 to 100 parts by weight, component (b) is 1 to 10 parts by weight, component (c) is 0.5 to 5 parts by weight, and component (d) is 1 to 10 parts by weight, and the weight of component (c) is less than the weight of component (b) and also less than the weight of component (d). The plastic sheet as described in claim 1, wherein "(b) styrene-conjugated diene block copolymer" is selected from at least one of the following groups: styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), styrene-ethylene/butene-styrene block copolymer (SEBS), styrene-ethylene/propylene-styrene block copolymer (SEPS), styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), styrene-butadiene-butene-styrene block copolymer (SBBS), styrene-butadiene diblock copolymer, and hydrogenated styrene-butadiene block copolymer. The plastic sheet as described in claim 2, wherein the weight average molecular weight (Mw) of the "(b) styrene-conjugated diene block copolymer" is from 1.0 × ^10⁴ to 5.0 × ^10⁵ . The plastic sheet as described in claim 1, wherein "(c) amino-modified styrene-conjugated diene block copolymer" is selected from at least one of the following groups: amino-modified styrene-butadiene-styrene block copolymer (SBS), amino-modified styrene-isoprene-styrene block copolymer (SIS), amino-modified styrene-ethylene/butene-styrene block copolymer (SEBS), amino-modified styrene-ethylene/propylene-styrene block copolymer (SEPS), amino-modified styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), amino-modified styrene-butadiene-butene-styrene block copolymer (SBBS), amino-modified styrene-butadiene diblock copolymer, and amino-modified hydrogenated styrene-butadiene block copolymer. The plastic sheet as described in claim 4, wherein the weight average molecular weight (Mw) of the "(c) amine-modified styrene-conjugated diene block copolymer" is from 1.0 × ^10⁴ to 5.0 × ^10⁵ . The plastic sheet as described in claim 1, wherein the "(d) anhydride-modified polyolefin" is selected from at least one of the following groups: maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene, maleic anhydride-modified ethylene-propylene copolymer and maleic anhydride-modified ethylene-octene copolymer. The plastic sheet as described in claim 6, wherein the weight average molecular weight (Mw) of the "(d) anhydride-modified polyolefin" is 2.0 × ^10⁴ to 2.0 × ^10⁵ . The plastic sheet as described in claim 1, wherein the thermoplastic composition comprises (a) 80 to 97 parts by weight, (b) 1 to 4 parts by weight, (c) 0.5 to 2 parts by weight and (d) 1.5 to 5 parts by weight. The plastic sheet as described in claim 1, wherein the first side has a first groove and the second side has a ridge, the cross-sectional shape of which matches the cross-sectional shape of the first groove. The plastic sheet as described in claim 1, wherein the first side has a first groove and the second side has a second groove. The plastic sheet as described in claim 10, wherein the shortest distance between the first groove and the bottom surface is the same as the shortest distance between the second groove and the bottom surface, the shortest distance between the first groove and the top surface, and the shortest distance between the second groove and the top surface.