Household appliance packaging material and preparation method thereof

Abstract

The invention discloses a household appliance packaging material and a preparation method thereof, and belongs to the field of household appliance packaging materials. The household appliance packaging material comprises polystyrene, recycled EPS particles, a chain extender and a physical crosslinking master batch, the physical crosslinking master batch is prepared by blending polystyrene microspheres containing functional groups and laponite nanosheets. The invention is applied to the aspect of household appliance packaging, solves the technical problem that the EPS performance is reduced in the process of recycling EPS as a raw material of a packaging buffer foam material in the existing industry, and further affects the reuse of the EPS in the packaging foam material, and has the characteristics of good buffer performance and foaming uniformity.

Description

Technical Field

[0001] The invention belongs to the field of household appliance packaging materials, and in particular relates to a household appliance packaging material and a preparation method thereof. Background Art

[0002] Expandable polystyrene (EPS) is widely used in cold chain transportation and cargo consignment filling to play the role of heat preservation and shock absorption. Therefore, the application prospect of recycled EPS is very broad. It is one of the plastics with great recycling value. However, as a foam material, the performance degradation caused during the recycling process affects the recycling of EPS.

[0003] At present, the main recycling schemes of EPS in the industry are as follows: 1) Incineration method to recover heat energy, place the waste EPS foam in a special incinerator, burn and recover heat to replace part of the fuel. It can partially replace the fuel of iron smelting, power generation, and combustion boilers. Although the combustion method can obtain energy, it requires the use of a special combustion blast furnace, otherwise the incomplete combustion of PS will produce harmful substances such as styrene and dioxins, causing secondary pollution to the environment. At the same time, the cost of the incineration recovery device is high, and the use value of the material has not been fully utilized. 2) Chemical pyrolysis is one of the high-quality recycling methods. The disadvantage is that the energy consumption in the recycling process is large, the recovery rate in the industrial production process is still low, and the problem of easy carbonization and accumulation of materials on the recycling equipment. 3) EPS foam compression granulation is currently the most widely used EPS recycling method. After the EPS foam waste is compressed or hot-melted by a professional foam compressor, a compact foam compression block will be formed. The compression block is extruded by an extrusion equipment to obtain the recycled EPS material. However, the recycled EPS material in the industry is still immature, and the main problem is the poor performance of the recycled EPS.

[0004] Chinese patent CN113980401A discloses a high-impact polystyrene material based on EPS foam modification and a preparation method thereof, comprising the following components in parts by weight: 60-80 parts of EPS recycled resin, 0-30 parts of general-purpose polystyrene GPPS resin, 10-20 parts of elastomer toughening agent, 0-5 parts of rubber powder toughening agent, 0.5-1.0 parts of light stabilizer, 0.1-0.5 parts of antioxidant and 0.1-0.5 parts of lubricant; each component is added to a high-speed mixer according to the above parts by weight, fully mixed, and then placed in a screw machine, the screw machine speed is controlled to 300-500rpm, the temperature is controlled to 180-210℃, extruded and granulated, and high-impact polystyrene particles based on EPS foam modification are prepared. This patent can recycle a large amount of EPS waste foam, is environmentally friendly, and the resulting polystyrene material has excellent comprehensive performance.

[0005] However, although the above patent realizes the recycling of EPS foam, it is applied to the recycled HIPS, and it still does not overcome the problem of EPS performance degradation during the recycling process of EPS as a raw material for packaging cushioning foam material. Summary of the invention

[0006] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is to overcome the technical problem that in the process of recycling EPS as a raw material for packaging cushioning foam materials in the existing industry, the performance of EPS decreases, which in turn affects the reuse of EPS in packaging foam materials. A home appliance packaging material with good cushioning performance and foaming uniformity and a preparation method thereof are proposed.

[0007] In order to solve the technical problem, the technical solution adopted by the present invention is:

[0008] On one hand, the present invention provides a household appliance packaging material, comprising polystyrene, recycled EPS particles, a chain extender, and a physical cross-linking masterbatch; the physical cross-linking masterbatch is prepared by blending polystyrene microspheres containing functional groups with lithium ion nanosheets.

[0009] Preferably, the functional group-containing polystyrene microspheres are selected from at least one of carboxyl polystyrene microspheres, amino polystyrene microspheres, and epoxy polystyrene microspheres.

[0010] Preferably, the mass ratio of the functional group-containing polystyrene microspheres to the lithium ion nanosheets in the physically crosslinked masterbatch is 5:3.

[0011] Preferably, the recycled EPS particles are obtained by crushing, extruding and granulating waste packaging EPS foam, and the chain extender is a chain extender containing an oxazoline group.

[0012] Preferably, the chain extender containing an oxazoline group is selected from one or two of poly(p-phenylene benzobisoxazole), 1,3-bis(2-oxazoline)benzene, poly(2-methyl-2-oxazoline), and poly(2-ethyl-2-oxazoline).

[0013] Preferably, the composition comprises, by weight: 40-65 parts of the polystyrene, 15-30 parts of the recycled EPS particles, 3-10 parts of a toughening agent, 10-16 parts of a chain extender, 0.2-0.4 parts of a physical crosslinking masterbatch, 1.6-2.4 parts of a foaming agent, and 8-12 parts of a coating agent.

[0014] Preferably, the tensile strength of the polystyrene is ≥40MPa, and the unnotched cantilever beam impact strength is ≥6KJ / m 2, melt index (200℃ / 5Kg) 1-5kg, Vicat softening point ≥88℃; the toughening agent is selected from one or two of styrene-butadiene-styrene block copolymers, styrene-ethylene-butylene-styrene block copolymers, acrylic core-shell copolymers, styrene-acrylonitrile low molecular weight random copolymers, styrene-isoprene-styrene, silicone rubber, and ABS rubber; the foaming agent is selected from at least one of petroleum ether, pentane, butane, and freon; the coating agent is selected from zinc stearate and / or calcium stearate.

[0015] Another aspect of the present invention provides a method for preparing the household appliance packaging material described in any of the above technical solutions, comprising: a step of preparing recycled EPS particles, a step of chain extension of recycled EPS particles, a step of preparing physically cross-linked masterbatch, and a step of extrusion granulation;

[0016] The chain extension step of the recycled EPS particles comprises: drying the recycled EPS particles, adding 1-2% of the chain extender, extruding through a single screw extruder, controlling the extrusion temperature at 190-210°C, the rotation speed at 80r / min, the feeding speed at 4.0Hz, extruding, drying and granulating to obtain chain-extended recycled EPS particles.

[0017] Preferably, the extrusion granulation step comprises: adding the polystyrene, the recycled EPS particles after chain extension, the toughening agent, the coating agent and the physical cross-linking masterbatch into a twin-screw extruder, extruding and granulating through the twin-screw extruder, and adding the foaming agent through an auxiliary machine; the processing temperature of the twin-screw extruder is 180-200°C, and the twin-screw extruder includes seven temperature zones: one section at 180°C, the second section at 185°C, the third section at 200°C, the fourth section at 200°C, the fifth section at 210°C, the sixth section at 215°C, and the seventh section at 215°C, and the screw speed is 350r / min.

[0018] Preferably, the step of preparing the recycled EPS particles comprises: pre-treating the waste packaging EPS foam to remove impurities, then crushing it into fine particles, and heating, extruding and granulating the fine particles to form the recycled EPS particles;

[0019] The physical cross-linking masterbatch preparation step comprises: adding the functional group-containing polystyrene microspheres and the lithium ion nanosheets in a ratio of 5:3 with a low mixing pot, and stirring, standing after stirring, and extruding the standing mixture into granules through a twin-screw extruder, wherein the processing temperature of the twin-screw extruder is 180-200° C., and the extruder includes seven temperature zones: the first section is 180° C., the second section is 185° C., the third section is 200° C., the fourth section is 200° C., the fifth section is 190° C., the sixth section is 195° C., and the seventh section is 195° C. The screw speed is 350 r / min, so as to obtain the physical cross-linking masterbatch.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention provides a household appliance packaging material, which realizes the reuse of recycled EPS as a raw material for packaging cushioning foam materials in household appliance packaging foam materials, and at the same time overcomes the problem of EPS performance degradation in the process of recycling EPS as a raw material for packaging cushioning foam materials through technical improvement. The household appliance packaging material has the characteristics of good cushioning performance and foaming uniformity. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A flow chart of the preparation process of the household appliance packaging material provided by an embodiment of the present invention;

[0023] Figure 2 A schematic diagram of the interaction between the components in the household appliance packaging material provided by an embodiment of the present invention;

[0024] Figure 3 It is a schematic diagram of the stress-buffering coefficient of the new EPS produced by the suspension method and the recycled EPS provided by the present invention;

[0025] Figure 4 Schematic diagram of strain-stress of new EPS produced by the suspension method and the regenerated EPS provided by the present invention. DETAILED DESCRIPTION

[0026] The technical scheme in the specific embodiment of the present invention will be described in detail and completely in conjunction with the accompanying drawings. Obviously, the described embodiments are only some specific implementation methods of the overall technical scheme of the present invention, rather than all implementation methods. Based on the overall concept of the present invention, all other embodiments obtained by ordinary technicians in this field fall within the scope of protection of the present invention.

[0027] On one hand, the present invention provides a household appliance packaging material, comprising polystyrene, recycled EPS particles, a chain extender, and a physical cross-linking masterbatch; the physical cross-linking masterbatch is prepared by blending polystyrene microspheres containing functional groups with lithium ion nanosheets.

[0028] Expandable polystyrene (EPS) is a foaming material with excellent performance and price advantage, and has been widely concerned and studied in home appliance packaging. Existing packaging materials are all disposable and discarded after use, causing environmental pollution. Therefore, it is very important to study the technology of recycling discarded EPS in home appliance packaging. The above-mentioned home appliance packaging material of the present invention realizes the reuse of recycled EPS as a raw material for packaging cushioning foam materials in home appliance packaging foam materials. At the same time, through technical improvements, the problem of EPS performance degradation in the process of recycling EPS as a raw material for packaging cushioning foam materials is overcome. The home appliance packaging material has the characteristics of good cushioning performance and foaming uniformity. The present invention analyzes the reasons affecting the performance attenuation of recycled EPS materials and studies the technical scheme for improving the performance of recycled EPS materials. By adding physical cross-linking points in the material formula, the physical cross-linking ability of the recycled EPS material is improved, and the cushioning performance of the recycled EPS is improved; at the same time, the physical cross-linking points are used as nucleating agents for foaming EPS to improve the uniformity of recycled EPS foaming; through the above scheme, the recycled EPS reaches the performance of a new EPS, and the technical difficulties of the application of recycled EPS in home appliance packaging are solved. Specifically: Through the preparation of physical cross-linking masterbatch, the polystyrene macromolecular chain segments are easy to entangle with each other, thereby improving the physical cross-linking ability of EPS, making the polyethylene molecular chain not very flexible. During the foaming process, the molecular chain spacing of EPS particles increases after foaming, the movement space of the chain segments increases, and the flexibility of the polystyrene molecular chain is enhanced, which increases the elasticity of EPS foamed particles. At the same time, the mineral components in the physical cross-linking masterbatch act as foaming nucleating agents, and are evenly distributed around the nucleating agents with the foaming agents. The nucleating agents and EPS molecules form an interface with low potential energy, which makes it easy for the foaming agent gas to gather here to form bubble nuclei. A large number of evenly distributed bubble nuclei appear in the whole system at the same time, and finally a high-quality foam with fine and uniform pores is obtained during the molding process, thereby improving the cushioning performance of the recycled EPS material.

[0029] It should be noted that the technical solution of the present invention limits the addition of functional group-containing polystyrene microspheres and lithium ion nanosheets to the system in the form of masterbatch. The reason is that the preparation of the physical cross-linked masterbatch enables the functional group-containing polystyrene microspheres and lithium ion nanosheets to be evenly dispersed. After extrusion by a twin-screw extruder, a preliminary electrostatic adsorption effect is formed between the negatively charged end-group polystyrene microspheres and the flaky lithium ion nanoparticles, providing cross-linking points for the cross-linking of the next step of regenerating the EPS macromolecular chain segments.

[0030] The addition of the physical cross-linking masterbatch of the present invention is the key to obtaining high-cushioning, high-performance recycled EPS materials:

[0031] First, if Figure 2As shown, the lithium algae is a flaky lithium algae nanoparticle, which has an octahedral structure, and the circular surface of the crystal has a negative charge, and the edge has a smaller negative charge. The charged flaky lithium algae nanoparticles can undergo electrostatic adsorption with other charged functional tube polymers. The present invention adds negatively charged carboxyl polystyrene microspheres, whose terminal carboxyl groups usually have a certain negative charge, and forms an electrostatic adsorption effect with the flaky lithium algae nanoparticles, so that in the entire regenerated EPS system, the electrostatic adsorption effect serves as a physical crosslinking point of the EPS macromolecular chain. At the same time, the terminal polystyrene microspheres and the EPS molecules after chain extension undergo entanglement of macromolecular chain segments, thereby ensuring the crosslinking of different EPS macromolecular chain segments, increasing the crosslinking density of the regenerated EPS molecules, and thus improving its buffering performance.

[0032] Secondly, for the recycled EPS material, it has been processed many times, with a wide molecular weight distribution, large structural differences, and large free space differences, which can easily lead to uneven distribution of the foaming agent inside the EPS beads. The bubble nuclei are formed earlier in places with higher foaming agent content, and later in places with lower content. Since the bubble nuclei do not appear at the same time, the pores are large and uneven. The physically cross-linked masterbatch, flaky lithium alkali nanoparticles and polystyrene microspheres containing functional groups added to the system act as foaming nucleating agents. At the location where the foaming agent and the nucleating agent are evenly distributed, the nucleating agent and the EPS molecules form an interface with low potential energy, making it easy for the foaming agent gas to gather into bubble nuclei from here. The influencing mechanism for improving the performance of recycled EPS materials is as follows: 1) Lithium nitride and terminal polystyrene particles in the physical cross-linking masterbatch act as nucleating agents, adsorbing foaming gas to form bubble nuclei, controlling the number of pores and making the pores finer; 2) Lithium nitride can improve the melt properties of the resin, and calcium carbonate with relatively high rigidity can slow down the deformation and mobility of the melt, thereby inhibiting the rapid expansion of the pores and controlling the pore size to be finer, thereby improving the uniformity, cushioning and mechanical properties of the foaming system.

[0033] In a preferred embodiment, the polystyrene microspheres containing functional groups are selected from at least one of carboxyl polystyrene microspheres, amino polystyrene microspheres, and epoxy polystyrene microspheres. The technical solution specifically limits the types of polystyrene microspheres containing functional groups because the polystyrene microspheres with the above functional groups have been chemically modified on the surface and functional groups have been introduced. The presence of the functional groups makes the microsphere surface negatively charged, thereby enhancing the ability of the microspheres to bind to the flaky lithium ion.

[0034] In a preferred embodiment, the mass ratio of the functional group-containing polystyrene microspheres to the lithium ion nanosheets in the physically cross-linked masterbatch is 5: 3. The technical solution specifically defines the mass ratio of the functional group-containing polystyrene microspheres to the lithium ion nanosheets in the physically cross-linked masterbatch, and the content of the polystyrene microspheres is greater than that of the lithium ion nanosheets, so that the polystyrene molecular segments uniformly wrap the nano-sheet lithium ion nanosheets. However, the excessive content of the polystyrene microspheres increases the cost of the recycled EPS material.

[0035] In a preferred embodiment, the recycled EPS particles are obtained by crushing, extruding and granulating waste packaging EPS foam, and the chain extender is a chain extender containing an oxazoline group. The use of a bicyclic chain extender in the material formula is conducive to increasing the molecular weight of the recycled EPS. The recycled EPS contains recycled EPS, which has a low molecular weight and a relatively wide molecular weight distribution. In order to ensure the heat resistance of the recycled EPS parts, the present invention adds an oxazoline group chain extender to increase the molecular weight of the recycled PS material and reduce its molecular weight distribution, thereby improving the heat resistance of the recycled EPS material. In a preferred embodiment, the chain extender containing an oxazoline group is selected from one or two of poly(p-phenylene benzobisoxazole), 1,3-bis(2-oxazoline)benzene, poly(2-methyl-2-oxazoline), and poly(2-ethyl-2-oxazoline).

[0036] In a preferred embodiment, the composition comprises, by weight: 40-65 parts of the polystyrene, 15-30 parts of the recycled EPS particles, 3-10 parts of a toughening agent, 10-16 parts of a chain extender, 0.2-0.4 parts of a physical crosslinking masterbatch, 1.6-2.4 parts of a foaming agent, and 8-12 parts of a coating agent. The technical solution specifically defines the amounts of polystyrene, recycled EPS particles, toughening agent, chain extender, physical crosslinking masterbatch, foaming agent and coating agent. It can be understood that the amount of polystyrene can also be 45 parts, 50 parts, 55 parts, 60 parts and any value within the range thereof, the amount of recycled EPS particles can also be 20 parts, 25 parts and any value within the range thereof, the amount of toughening agent can also be 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts and any value within the range thereof, the amount of chain extender can also be 11 parts, 12 parts, 13 parts, 14 parts, 15 parts and any value within the range thereof, the amount of physical crosslinking masterbatch can also be 0.3 parts and any value within the range thereof, the amount of foaming agent can also be 1.8 parts, 2.0 parts, 2.2 parts and any value within the range thereof, and the amount of coating agent can also be 9 parts, 10 parts, 11 parts and any value within the range thereof.

[0037] In a preferred embodiment, the tensile strength of the polystyrene is ≥40MPa, and the unnotched cantilever beam impact strength is ≥6KJ / m 2, melt index (200℃ / 5Kg) 1-5kg, Vicat softening point ≥88℃; the toughening agent is selected from one or two of styrene-butadiene-styrene block copolymers, styrene-ethylene-butylene-styrene block copolymers, acrylic core-shell copolymers, styrene-acrylonitrile low molecular weight random copolymers, styrene-isoprene-styrene, silicone rubber, and ABS rubber; the foaming agent is selected from at least one of petroleum ether, pentane, butane, and freon; the coating agent is selected from zinc stearate and / or calcium stearate.

[0038] Another aspect of the present invention provides a method for preparing the household appliance packaging material according to any of the above technical solutions, such as Figure 1 As shown, it includes: a step of preparing recycled EPS particles, a step of chain extension of recycled EPS particles, a step of preparing physical crosslinking masterbatch, and an extrusion granulation step; the step of chain extension of recycled EPS particles includes: drying the recycled EPS particles, adding 1-2% of the chain extender, extruding through a single screw extruder, controlling the extrusion temperature at 190-210°C, the rotation speed at 80r / min, the feeding speed at 4.0Hz, extruding, drying and granulating to obtain recycled EPS particles after chain extension. The process of chain extension of recycled EPS particles using a chain extender is:

[0039]

[0040] In a preferred embodiment, the extrusion granulation step includes: adding the polystyrene, the recycled EPS particles after chain extension, the toughening agent, the coating agent and the physical cross-linking masterbatch into a twin-screw extruder, extruding and granulating through the twin-screw extruder, and adding the foaming agent through an auxiliary machine; the processing temperature of the twin-screw extruder is 180-200°C, and the twin-screw extruder includes seven temperature zones: one section at 180°C, the second section at 185°C, the third section at 200°C, the fourth section at 200°C, the fifth section at 210°C, the sixth section at 215°C, and the seventh section at 215°C, and the screw speed is 350r / min.

[0041] In a preferred embodiment, the step of preparing the recycled EPS particles comprises: pre-treating the waste packaging EPS foam to remove impurities, then crushing it into fine particles, and heating, extruding and granulating the fine particles to form the recycled EPS particles;

[0042] The physical cross-linking masterbatch preparation step comprises: adding the functional group-containing polystyrene microspheres and the lithium ion nanosheets in a ratio of 5:3 with a low mixing pot, and stirring, standing after stirring, and extruding the standing mixture into granules through a twin-screw extruder, wherein the processing temperature of the twin-screw extruder is 180-200° C., and the extruder includes seven temperature zones: the first section is 180° C., the second section is 185° C., the third section is 200° C., the fourth section is 200° C., the fifth section is 190° C., the sixth section is 195° C., and the seventh section is 195° C. The screw speed is 350 r / min, so as to obtain the physical cross-linking masterbatch.

[0043] In order to more clearly and in detail introduce the household appliance packaging material and the preparation method thereof provided by the embodiments of the present invention, a description will be given below in conjunction with specific embodiments.

[0044] Recycled packaging material for refrigerator

[0045] 45-60 parts by weight of new polystyrene, 30-50 parts by weight of recycled EPS, 2-6 parts by weight of toughening agent, 1-3 parts by weight of chain extender, 2-5 parts by weight of lithium ion, 1-3 parts by weight of terminal polystyrene, 4-6 parts by weight of foaming agent, and 1-2 parts by weight of coating agent.

[0046] Example 1

[0047] According to the above description, weigh the raw material components according to the following weight percentage: 41 kg of new polystyrene, 35 kg of recycled EPS, 2 kg of toughening agent, 1 kg of chain extender, 5 kg of lithium diatomaceous earth, 3 kg of terminal polystyrene, 5 kg of lithium diatomaceous earth, 3 kg of terminal polystyrene, 4 kg of foaming agent, and 1 kg of coating agent.

[0048] 35kg of recycled EPS particles were dried in a vacuum drying oven for 10h, 1kg of 1,3-bis(2-oxazolinyl)benzene (MPBO) chain extender was added, and extruded through a single screw extruder. The extrusion temperature was controlled at 190-210℃, the rotation speed was 80r / min, and the feeding speed was 4.0Hz. The chain-extended recycled EPS material was obtained by extrusion drying and granulation. 5kg of lithium algae and 3kg of terminal polystyrene were stirred in a low mixing pot according to a certain proportion. After stirring, it was left to stand for 24h to obtain a physically cross-linked masterbatch, which was retained for standby use. 41kg of new PS particles, 36kg of recycled EPS material after chain extension, 2kg of toughening agent, 1kg of coating agent, and 8kg of physically cross-linked masterbatch were added to the twin-screw extruder, extruded and granulated by the twin-screw extruder, and 4kg of foaming agent pentane was added through the auxiliary machine. The processing temperature of the twin-screw extruder is 180-200°C. The extruder includes seven temperature zones, including one section at 180°C, two sections at 185°C, three sections at 200°C, four sections at 200°C, five sections at 2100°C, six sections at 215°C, and seven sections at 215°C. The screw speed is 350r / min.

[0049] Example 2

[0050] According to the above description, the raw material components are weighed according to the following weight percentage: 41 kg of new polystyrene, 35 kg of recycled EPS, 2 kg of toughening agent, 5 kg of lithium diatomaceous earth, 3 kg of terminal polystyrene, 5 kg of lithium diatomaceous earth, 3 kg of terminal polystyrene, 4 kg of foaming agent, and 1 kg of coating agent.

[0051] Dry 35kg of recycled EPS particles in a vacuum drying oven for 10 hours, extrude through a single-screw extruder, control the extrusion temperature at 190-210℃, rotate speed at 80r / min, feed rate at 4.0Hz, extrude and dry granulate to obtain chain-extended recycled EPS material. Stir 5kg of lithium tantalum and 3kg of terminal polystyrene in a low mixing pot in a certain proportion, let it stand for 24 hours after stirring, obtain physically cross-linked masterbatch, and keep it for later use. Add 41kg of new PS particles, 36kg of chain-extended recycled EPS material, 2kg of toughening agent, 1kg of coating agent, and 8kg of physically cross-linked masterbatch to a twin-screw extruder, extrude and granulate through a twin-screw extruder, and add 4kg of foaming agent pentane through an auxiliary machine. The processing temperature of the twin-screw extruder is 180-200°C. The extruder includes seven temperature zones, including one section at 180°C, two sections at 185°C, three sections at 200°C, four sections at 200°C, five sections at 2100°C, six sections at 215°C, and seven sections at 215°C. The screw speed is 350r / min.

[0052] The preparation method is the same as that of Example 1, except that the raw materials and the amounts of the raw materials are different, as shown in Table 1.

[0053] Example 3

[0054] According to the above description, weigh the raw material components according to the following weight percentage: 41 kg of new polystyrene, 35 kg of recycled EPS, 2 kg of toughening agent, 1 kg of chain extender, 5 kg of lithium diatomaceous earth, 3 kg of terminal polystyrene, 5 kg of lithium diatomaceous earth, 3 kg of terminal polystyrene, 4 kg of foaming agent, and 1 kg of coating agent.

[0055] 35kg of recycled EPS particles were dried in a vacuum drying oven for 10h, 1kg of 1,3-bis(2-oxazolinyl)benzene (MPBO) chain extender was added, and extruded through a single screw extruder. The extrusion temperature was controlled at 190-210℃, the rotation speed was 80r / min, and the feeding speed was 4.0Hz. The chain-extended recycled EPS material was obtained by extrusion drying and granulation. 5kg of lithium algae and 3kg of terminal polystyrene were stirred in a low mixing pot according to a certain proportion. After stirring, it was left to stand for 24h to obtain a physical cross-linked masterbatch, which was retained for standby use. 41kg of new PS particles, 36kg of recycled EPS material after chain extension, 2kg of toughening agent, 1kg of coating agent, and 4kg of physical cross-linked masterbatch were added to the twin-screw extruder, extruded and granulated by the twin-screw extruder, and 4kg of foaming agent pentane was added through the auxiliary machine. The processing temperature of the twin-screw extruder is 180-200°C. The extruder includes seven temperature zones, including one section at 180°C, two sections at 185°C, three sections at 200°C, four sections at 200°C, five sections at 2100°C, six sections at 215°C, and seven sections at 215°C. The screw speed is 350r / min.

[0056] The preparation method is the same as that of Example 1, except that the raw materials and the amounts of the raw materials are different, as shown in Table 1.

[0057] Example 4

[0058] According to the above description, weigh the raw material components according to the following weight percentage: 41 kg of new polystyrene, 35 kg of recycled EPS, 2 kg of toughening agent, 1 kg of chain extender, 5 kg of lithium diatomaceous earth, 3 kg of terminal polystyrene, 5 kg of lithium diatomaceous earth, 3 kg of terminal polystyrene, 4 kg of foaming agent, and 1 kg of coating agent.

[0059] 35kg of recycled EPS particles were dried in a vacuum drying oven for 10h, 1kg of 1,3-bis(2-oxazolinyl)benzene (MPBO) chain extender was added, and the particles were extruded through a single screw extruder. The extrusion temperature was controlled at 190-210℃, the rotation speed was 80r / min, and the feeding speed was 4.0Hz. The extended chain recycled EPS material was obtained by extrusion drying and granulation. 41kg of new PS particles, 36kg of extended chain recycled EPS material, 2kg of toughening agent, and 1kg of coating agent were added to a twin-screw extruder, extruded and granulated through a twin-screw extruder, and 4kg of foaming agent pentane was added through an auxiliary machine. The processing temperature of the twin-screw extruder is 180-200℃, and the extruder includes seven temperature zones, one of which is 180℃, the second is 185℃, the third is 200℃, the fourth is 200℃, the fifth is 2100℃, the sixth is 215℃, and the seventh is 215℃. The screw speed is 350r / min.

[0060] The preparation method is the same as that of Example 1, except that the raw materials and the amounts of the raw materials are different, as shown in Table 1.

[0061] Example 5

[0062] According to the above description, weigh the raw material components according to the following weight percentage: 41 kg of new polystyrene, 35 kg of recycled EPS, 2 kg of toughening agent, 1 kg of chain extender, 5 kg of lithium diatomaceous earth, 3 kg of terminal polystyrene, 5 kg of lithium diatomaceous earth, 3 kg of terminal polystyrene, 4 kg of foaming agent, and 1 kg of coating agent.

[0063] 35kg of recycled EPS particles were dried in a vacuum drying oven for 10h, 1kg of 1,3-bis(2-oxazolinyl)benzene (MPBO) chain extender was added, and extruded through a single screw extruder. The extrusion temperature was controlled at 190-210℃, the rotation speed was 80r / min, and the feeding speed was 4.0Hz. The chain-extended recycled EPS material was obtained by extrusion drying and granulation. 5kg of lithium algae and 3kg of terminal polystyrene were stirred in a low mixing pot according to a certain proportion. After stirring, it was left to stand for 24h to obtain a physically cross-linked masterbatch, which was retained for standby use. 41kg of new PS particles, 36kg of recycled EPS material after chain extension, 2kg of toughening agent, 1kg of coating agent, and 16kg of physically cross-linked masterbatch were added to the twin-screw extruder, extruded and granulated by the twin-screw extruder, and 4kg of foaming agent pentane was added through the auxiliary machine. The processing temperature of the twin-screw extruder is 180-200°C. The extruder includes seven temperature zones, including one section at 180°C, two sections at 185°C, three sections at 200°C, four sections at 200°C, five sections at 2100°C, six sections at 215°C, and seven sections at 215°C. The screw speed is 350r / min.

[0064] The preparation method is the same as that of Example 1, except that the raw materials and the amounts of the raw materials are different, as shown in Table 1.

[0065] Example 6

[0066] According to the above description, weigh the raw material components according to the following weight percentage: 51 kg of new polystyrene, 25 kg of recycled EPS, 2 kg of toughening agent, 5 kg of lithium diatomaceous earth, 3 kg of terminal polystyrene, 5 kg of lithium diatomaceous earth, 3 kg of terminal polystyrene, 4 kg of foaming agent, and 1 kg of coating agent.

[0067] 25kg of recycled EPS particles were dried in a vacuum drying oven for 10 hours, extruded through a single screw extruder, the extrusion temperature was controlled at 190-210℃, the rotation speed was 80r / min, the feeding speed was 4.0Hz, and the chain-extended recycled EPS material was obtained by extrusion drying and granulation. 51kg of new PS particles, 36kg of recycled EPS material after chain extension, 2kg of toughening agent, and 1kg of coating agent were added to a twin-screw extruder, extruded and granulated through a twin-screw extruder, and 4kg of foaming agent pentane was added through an auxiliary machine. The processing temperature of the twin-screw extruder is 180-200℃, and the extruder includes seven temperature zones, one of which is 180℃, the second is 185℃, the third is 200℃, the fourth is 200℃, the fifth is 2100℃, the sixth is 215℃, the seventh is 215℃, and the screw speed is 350r / min.

[0068] The preparation method is the same as that of Example 1, except that the raw materials and the amounts of the raw materials are different, as shown in Table 1.

[0069] Comparative Example 1

[0070] According to the above description, the raw material components are weighed according to the following weight percentages: 94 kg of new polystyrene, 2 kg of toughening agent, and 4 kg of foaming agent.

[0071] 94kg of new PS particles and 2kg of toughening agent are added to the twin-screw extruder, extruded and granulated by the twin-screw extruder, and 4kg of pentane, a foaming agent, is added through an auxiliary machine. The processing temperature of the twin-screw extruder is 180-200°C, and the extruder includes seven temperature zones, one of which is 180°C, the second is 185°C, the third is 200°C, the fourth is 200°C, the fifth is 2100°C, the sixth is 215°C, and the seventh is 215°C. The screw speed is 350r / min.

[0072] The preparation method is the same as that of Example 1, except that the raw materials and the amounts of the raw materials are different, as shown in Table 1.

[0073] Comparative Example 2

[0074] The raw material components were weighed according to the above description according to the following weight percentages: 41 kg of new polystyrene, 35 kg of recycled EPS, 2 kg of toughening agent, 1 kg of chain extender, 5 kg of terminal polystyrene microspheres, 3 kg of lithium ion nanosheets, 4 kg of foaming agent, and 1 kg of coating agent.

[0075] 35kg of recycled EPS particles were dried in a vacuum drying oven for 10h, 1kg of 1,3-bis(2-oxazolinyl)benzene (MPBO) chain extender was added, and the particles were extruded through a single screw extruder. The extrusion temperature was controlled at 190-210℃, the rotation speed was 80r / min, and the feeding speed was 4.0Hz. The extended recycled EPS material was obtained by extrusion drying and granulation. 41kg of new PS particles, 36kg of extended recycled EPS material, 2kg of toughening agent, 1kg of coating agent, 5kg of end-group polystyrene microspheres, and 3kg of lithium ion nanosheets were added to a twin-screw extruder, extruded and granulated by the twin-screw extruder, and 4kg of pentane, a foaming agent, was added through an auxiliary machine. The processing temperature of the twin-screw extruder is 180-200°C. The extruder includes seven temperature zones, including one section at 180°C, two sections at 185°C, three sections at 200°C, four sections at 200°C, five sections at 2100°C, six sections at 215°C, and seven sections at 215°C. The screw speed is 350r / min.

[0076] The preparation method is the same as that of Example 1, except that the raw materials and the amounts of the raw materials are different, as shown in Table 1.

[0077] Table 1 A kind of recycled packaging material for refrigerator in the embodiment and comparative example

[0078]

[0079] Performance Testing

[0080] The recycled packaging material for refrigerators prepared in Examples 1-6 and Comparative Examples 1-2 was tested, and the test results are shown in Table 2.

[0081] Table 2 Performance test results of a recycled packaging material for refrigerators prepared in Examples 1-6 and Comparative Examples 1-2

[0082]

[0083] It can be seen from Table 2 that Example 1 is a typical scheme of recycled EPS, and Comparative Example 1 is a scheme of new EPS material. Through the addition of physical cross-linking masterbatch, the compression performance of the recycled EPS material is basically consistent with that of the new EPS material, and the fracture bending strength and fracture toughness of the recycled EPS material are better than those of the new EPS.

[0084] In Example 2, without adding a chain extender, the temperature resistance of the recycled EPS material is significantly reduced, which is not conducive to molding processing. Figure 3 and Figure 4 It can be analyzed that the addition of physical cross-linking masterbatch improves the cross-linking of EPS molecular segments, and lithium ion acts as a foaming nucleating agent, making the EPS pores uniform and stable, thereby improving its compression performance and cushioning performance.

Claims

1. A household appliance packaging material, characterized in that: The invention comprises polystyrene, recycled EPS particles, a chain extender, and a physical cross-linking masterbatch; the physical cross-linking masterbatch is prepared by blending polystyrene microspheres containing functional groups with lithium ion nanosheets.

2. The household appliance packaging material according to claim 1, characterized in that: The functional group-containing polystyrene microspheres are selected from at least one of carboxyl polystyrene microspheres, amino polystyrene microspheres, and epoxy polystyrene microspheres.

3. The household appliance packaging material according to claim 1, characterized in that: The mass ratio of the functional group-containing polystyrene microspheres to the lithium ion nanosheets in the physically crosslinked masterbatch is 5:

3.

4. The household appliance packaging material according to claim 1, characterized in that: The recycled EPS particles are obtained by crushing, extruding and granulating waste packaging EPS foam, and the chain extender is a chain extender containing an oxazoline group.

5. The household appliance packaging material according to claim 4, characterized in that: The chain extender containing oxazoline groups is selected from one or two of poly(p-phenylene benzobisoxazole), 1,3-bis(2-oxazoline)benzene, poly(2-methyl-2-oxazoline), and poly(2-ethyl-2-oxazoline).

6. The household appliance packaging material according to claim 1, characterized in that: In parts by weight, the composition comprises: 40-65 parts of the polystyrene, 15-30 parts of the recycled EPS particles, 3-10 parts of a toughening agent, 10-16 parts of a chain extender, 0.2-0.4 parts of a physical cross-linking masterbatch, 1.6-2.4 parts of a foaming agent, and 8-12 parts of a coating agent.

7. The household appliance packaging material according to claim 6, characterized in that: The tensile strength of the polystyrene is ≥40MPa, and the unnotched cantilever beam impact strength is ≥6KJ / m 2 , melt index (200℃ / 5Kg) 1-5kg, Vicat softening point ≥88℃; The toughening agent is selected from one or two of styrene-butadiene-styrene block copolymers, styrene-ethylene-butylene-styrene block copolymers, acrylic core-shell copolymers, low molecular weight random copolymers of styrene-acrylonitrile, styrene-isoprene-styrene, silicone rubber, and ABS rubber; The foaming agent is selected from at least one of petroleum ether, pentane, butane and freon; The coating agent is selected from zinc stearate and / or calcium stearate.

8. The method for preparing a household appliance packaging material according to any one of claims 1 to 7, characterized in that: include: A step of preparing recycled EPS particles, a step of chain extension of recycled EPS particles, a step of preparing physically cross-linked masterbatch, and an extrusion granulation step; The chain extension step of the recycled EPS particles comprises: drying the recycled EPS particles, adding 1-2% of the chain extender, extruding through a single screw extruder, controlling the extrusion temperature at 190-210°C, the rotation speed at 80r / min, the feeding speed at 4.0Hz, extruding, drying and granulating to obtain chain-extended recycled EPS particles.

9. The method for preparing the household appliance packaging material according to claim 8, characterized in that: The extrusion granulation step comprises: adding the polystyrene, the recycled EPS particles after chain extension, the toughening agent, the coating agent and the physical cross-linking masterbatch into a twin-screw extruder, extruding and granulating through the twin-screw extruder, and adding the foaming agent through an auxiliary machine; the processing temperature of the twin-screw extruder is 180-200° C., and the twin-screw extruder includes seven temperature zones: the first section is 180° C., the second section is 185° C., the third section is 200° C., the fourth section is 200° C., the fifth section is 210° C., the sixth section is 215° C., and the seventh section is 215° C., and the screw speed is 350 r / min.

10. The method for preparing household appliance packaging material according to claim 8, characterized in that: The step of preparing the recycled EPS particles comprises: pre-treating the waste packaging EPS foam to remove impurities, then crushing it into fine particles, and heating, extruding and granulating the fine particles to form the recycled EPS particles; The physical cross-linking masterbatch preparation step comprises: adding the functional group-containing polystyrene microspheres and the lithium ion nanosheets in a ratio of 5:3 with a low mixing pot, and stirring, standing after stirring, and extruding the standing mixture into granules through a twin-screw extruder, wherein the processing temperature of the twin-screw extruder is 180-200° C., and the extruder includes seven temperature zones: the first section is 180° C., the second section is 185° C., the third section is 200° C., the fourth section is 200° C., the fifth section is 190° C., the sixth section is 195° C., and the seventh section is 195° C. The screw speed is 350 r / min, so as to obtain the physical cross-linking masterbatch.

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