Regenerated PET / ABS alloy with high ultrasonic welding strength and high toughness as well as preparation method and application of regenerated PET / ABS alloy

Abstract

The invention relates to a regenerated PET / ABS (Polyethylene Terephthalate / Acrylonitrile Butadiene Styrene) alloy with high ultrasonic welding strength and high toughness as well as a preparation method and application thereof. The regenerated PET / ABS plastic provided by the invention is prepared from the following components in parts by weight: 71 to 80 parts of regenerated PET, 15 to 22 parts of ABS, 3 to 8 parts of long-chain flexibilizer, 1 to 5 parts of compatilizer and 0.1 to 0.5 part of antioxidant. Compared with a traditional pure PET material, the novel composite material provided by the invention has the advantages that the toughness of the material is remarkably improved on the basis of keeping light weight and durability, and meanwhile, PET / ABS obtains good ultrasonic welding capacity.

Description

Technical Field

[0001] The invention belongs to the field of recycled materials, and in particular relates to a recycled PET / ABS alloy with high ultrasonic welding strength and high toughness, and a preparation method and application thereof. Background Art

[0002] With the increasing awareness of environmental protection and the continuous attention of families to the healthy growth of children, children's toys have become an indispensable part of children's daily life, and the safety and environmental protection of their materials have become important considerations for consumers. Traditional children's toys are mostly made of virgin plastic or other non-environmentally friendly materials. These materials may burden the environment during production, use and disposal, and some materials contain harmful substances, posing a potential threat to children's health. Therefore, it is particularly important to develop a children's toy material that is both safe and environmentally friendly.

[0003] The selection of materials for children's toys must strictly follow the safety principle to ensure that they are non-toxic, harmless, and non-irritating, and can effectively prevent children from having adverse reactions due to accidental ingestion, inhalation, or skin contact during play. In addition, the materials should have good durability, drop resistance, and easy cleaning characteristics to adapt to the active nature of children. At the same time, considering the particularity of children's growth and development, the materials should also avoid using ingredients that may cause allergies or affect children's physical and mental health.

[0004] As an important part of the circular economy, the value of recycled plastics lies in the fact that by recycling, processing and reusing waste plastics, it reduces dependence on primary resources, reduces energy consumption and greenhouse gas emissions, and helps alleviate environmental pressure. For the children's toy industry, the use of recycled plastics is not only in line with the trend of environmental protection, but also can enhance the added value of products through innovative design and technical means, and meet consumers' demand for green and sustainable products.

[0005] Recycled PET (polyethylene terephthalate) is a widely recycled plastic material with excellent physical properties and chemical stability. It is non-toxic, odorless, highly transparent, and easy to process and shape. Using it in the manufacture of children's toys can not only effectively ensure the safety of toys, but also significantly improve the environmental performance of toys. Recycled PET materials are strictly screened, cleaned, crushed, melted and other process treatments to remove impurities and retain their excellent properties, while reducing production costs and achieving a win-win situation of economic and environmental benefits.

[0006] Although recycled PET has shown great potential as an environmentally friendly material in many fields, it faces the problems of difficult injection molding and high product brittleness when directly used in the manufacture of children's toys. Conventional PET will also have the problem of brittle fracture at the stress concentration point after injection molding. This brittleness not only limits the toy's anti-fall performance, but may also affect the overall durability and safety of the toy. Therefore, in order to meet the strict requirements of children's toys for material properties, it has become a necessary step to modify the recycled PET. The modification aims to improve the toughness, strength and injection molding processing performance of the recycled PET, so as to produce safe and durable children's toys.

[0007] The methods for toughening PET mainly include the following:

[0008] Blending modification: Blending PET with other tough polymers (such as elastomers, rubber particles, etc.) to form a composite system through physical or chemical effects to improve the toughness of PET. This method is simple and easy to implement, with relatively low cost, and is one of the commonly used toughening methods.

[0009] Copolymerization modification: By introducing flexible segments and optimizing the PET molecular chain structure, the processing performance and physical properties of PET are improved, but the PET content recycled by chemical methods is very high, making it difficult to achieve commercialization.

[0010] Plasticizers and nanofillers are additives that improve material properties. Although they can improve the softness, durability or other specific properties of toys to a certain extent, their use is strictly restricted in the manufacturing process of children's toys. This is mainly because these additives have the potential risk of being accidentally ingested by children. Long-term research on the effects of plasticizers and nanofillers on children's health is insufficient, and they may have adverse effects on children's health. Out of cautious consideration for children's safety, many countries have restricted their use in children's toys.

[0011] In the toughening modification of recycled PET, the use of olefin toughening agents is a possible option. Olefin toughening agents are generally effective in improving the toughness of PET. However, the addition of olefin toughening agents may change the surface properties of PET, making the material more difficult to process in post-processing processes such as ink printing, coloring, adhesiveness and ultrasonic welding. This is because olefin toughening agents may affect the surface energy, polarity or other surface properties of PET, thereby affecting its interaction with inks, adhesives or welding materials.

[0012] Another innovative strategy is to mix PET with other high-toughness materials to prepare plastic alloys with superior performance. It is difficult to achieve ideal compatibility and uniformity when recycled PET is blended with other high-toughness materials. In order to maintain the stability and processing performance of the alloy material, the amount of recycled PET added often needs to be strictly controlled, but the proportion of recycled PET added often does not exceed 30% of the total amount. This limits the environmental contribution value of recycled PET products. Summary of the invention

[0013] The purpose of the present invention is to provide a recycled PET / ABS alloy with high ultrasonic welding strength and high toughness, and a preparation method and application thereof in view of the problems existing in the prior art.

[0014] Compared with conventional PET, recycled PET will be degraded by aging and multiple thermal processing, resulting in lower viscosity and lower impact strength of recycled PET, which makes it more brittle. There are few viscosity types available for recycled PET, mainly 0.80dl / g for crushed flakes and 0.65dl / g for recycled PET particles. To be precise, conventional PET has more designability, while recycled PET has higher requirements for preparation.

[0015] The long-chain toughening agent in the present invention mainly plays an end-capping and toughening role on the recycled PET, which can ensure high toughness after modification. ABS mainly plays a toughening role and an auxiliary role in ultrasonic welding on the recycled PET, which can ensure high toughness and interface bonding during ultrasonic welding. The compatibilizer plays an end-capping and volume-increasing role on the recycled PET, avoids degradation during multiple processing of the recycled PET, and improves the dispersion of ABS in PET, which is very important for ultrasonic welding interface bonding.

[0016] The recycled PET of the present invention is more than 70%, and is a material with PET as the continuous phase. The present invention cannot use lubricants (such as EVA wax, OP wax, TAS-2A, ethylene bis stearamide EBS), which will have a very obvious deterioration effect on ultrasonic welding.

[0017] The purpose of the present invention can be achieved by the following scheme:

[0018] The present invention provides a recycled PET / ABS alloy with high ultrasonic welding strength and high toughness, comprising the following components in parts by weight:

[0019] Recycled PET 70-80 parts,

[0020] ABS15~22 parts,

[0021] 3-8 parts of long chain toughening agent,

[0022] 1 to 5 parts of compatibilizer,

[0023] Antioxidant 0.1-0.5 parts.

[0024] Preferably, the recycled PET is polyethylene terephthalate, with an average intrinsic viscosity of 0.70-0.85 dL / g, and the recycling source is mineral water bottles. Preferably, the PET viscosity is 0.75-0.85 dL / g, and more preferably, the PET viscosity is 0.80 dL / g.

[0025] Preferably, in the recycled PET / ABS alloy with high ultrasonic welding strength and high toughness, the mass percentage of recycled PET exceeds 70%.

[0026] The higher the recycled PET content, the better, which can meet the client's value demand for environmental protection and low carbon. However, the problem with too much PET content is that the toughness of the material and the ultrasonic welding effect cannot meet the requirements at the same time. The present invention is the result of balancing the recycled ratio, high toughness, and high ultrasonic welding strength. By blending long-chain toughening agents and high-rubber content ABS, it can ensure that the recycled ratio of PET is more than 70%, while obtaining high toughness and high ultrasonic welding strength.

[0027] Preferably, the recycled PET is preferably 70-75 parts, the ABS is preferably 18-22 parts, more preferably 18-20 parts, and the long-chain toughening agent is preferably 5-8 parts.

[0028] Preferably, the ABS is a styrene-acrylonitrile-butadiene copolymer, wherein the acrylonitrile content is 15-25%, the butadiene content is 40-55%, preferably ABS with 20% acrylonitrile and 55% butadiene. For PET alloys with a recycled PET content exceeding 70%, the present invention uses high rubber powder (butadiene content of 40-55%). If the common ABS on the market (butadiene content of 15-20%) is used, the PET / ABS ultrasonic welding strength will be greatly reduced.

[0029] The long-chain toughening agent includes one or more of EMA and EMA-GMA, and is preferably EMA-GMA.

[0030] When the content of recycled PET exceeds 70%, the toughness and ultrasonic welding strength are poor. Conventional toughening agents (such as SEBS, POE-g-MAH, etc.) have limited effect on improving the toughness and ultrasonic welding strength of recycled PET. The EMA olefin toughening agent used in the present invention has a significant toughening effect on PET alloys with a high content of recycled PET. The addition amount of less than 10% can achieve a significant improvement in impact strength and elongation at break. The mechanism of action of EMA includes providing flexible segments, interfering with the crystallization of PET, inducing silver streaks during fracture, increasing the deformation during fracture, and improving the energy absorption during fracture.

[0031] Preferably, the compatibilizer is one or more of SAG, SAN-MAH, SBS-MAH, preferably SAG.

[0032] Preferably, the antioxidant is one or more of a hindered phenol antioxidant or a phosphite antioxidant. The hindered phenol antioxidant includes pentaerythritol tetrakis[β-(3,5-di-tert-butyl 4-hydroxyphenyl) propionate], and the phosphite antioxidant includes triphenyl phosphate, tris(2,4-di-tert-butylphenyl) phosphite, and pentaerythritol diphosphite (2,4-di-tert-butylphenyl). The antioxidant is preferably a mixed antioxidant of a hindered phenol antioxidant and a phosphite antioxidant in a mass ratio of 1:1. The phosphite antioxidant is preferably pentaerythritol diphosphite (2,4-di-tert-butylphenyl).

[0033] Preferably, the ultrasonic welding strength of the recycled PET / ABS alloy is characterized by a pull-off force test, and the maximum pull force is greater than 500N. The notched impact strength of the recycled PET / ABS alloy can be guaranteed to be no less than 30kJ / m 2 .

[0034] Preferably, the components of the recycled PET / ABS alloy do not contain lubricants; the lubricants include one or more of EVA wax, OP wax, TAS-2A, and ethylene bisstearamide EBS.

[0035] The present invention also provides a method for preparing a recycled PET / ABS alloy plastic with high ultrasonic welding strength and high toughness, the method specifically comprising the following steps:

[0036] (1) Prepare the following components by weight:

[0037] (2) The components in step (1) are added into a high-speed mixer according to the above weight percentages, and after being fully mixed, they are placed in a screw machine, the speed of the screw machine is controlled to be 300-500 rpm, the temperature is controlled to be 230-245° C., and granulated by extrusion to prepare a PET / ABS alloy resin with a high recycling ratio that can be ultrasonically welded.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] (1) The present invention provides a new composite material. Compared with the traditional pure PET material, the material has significantly improved toughness while maintaining light weight and durability. This feature can effectively reduce the risk of breakage caused by falling or squeezing in the field of children's toys, thereby greatly improving the safety of children during play. In addition, the ingredients used in the material also meet the non-toxic safety requirements.

[0040] (2) Another significant advantage is its excellent environmental performance. By optimizing the material composition and production process, the recycling rate of this material is as high as over 70%, far exceeding the average level of similar products. This innovation not only reduces dependence on primary resources, but also reduces the pollution of waste to the environment, actively responds to the call for global sustainable development, and makes an important contribution to building a green and circular economic system.

[0041] (3) In order to broaden the scope of application and improve processing convenience, the material of the present invention has achieved a major breakthrough in post-processing connection performance. Compared with pure PET materials, this material not only supports traditional ultrasonic welding methods, but is also perfectly compatible with adhesive connections, and has a high strength retention rate after connection, ensuring the stability and durability of the product structure. This feature makes this material show great potential in the manufacture of complex structural parts, providing more flexible and efficient solutions for multiple fields such as toys, packaging, and electronic products.

[0042] (4) The surface polarity of the material of the present invention is significantly improved compared with the traditional toughened PET material. This improvement makes the surface of the material more suitable for surface treatment processes such as spray painting and ink printing. It not only has bright colors and clear patterns, but also has strong adhesion and is durable. DETAILED DESCRIPTION

[0043] The present invention is described in detail below in conjunction with specific embodiments. The following examples are implemented under the premise of the technical solution of the present invention, and provide detailed implementation methods and specific operation processes, which will help those skilled in the art to further understand the present invention. It should be pointed out that the protection scope of the present invention is not limited to the following embodiments, and several adjustments and improvements made under the premise of the concept of the present invention all belong to the protection scope of the present invention.

[0044] A method for preparing a recycled PET / ABS alloy resin with high ultrasonic welding strength and high toughness, the method comprising the following steps:

[0045] (1) According to the weight percentage of the ingredients in Table 1, the raw materials were added into a high-speed mixer and mixed thoroughly, and then placed in a screw machine, the speed of the screw machine was controlled to be 400 rpm, the temperature was controlled to be 230-245° C., and extruded into granules to prepare a PET / ABS alloy resin with a high recycling ratio that can be ultrasonically welded;

[0046] Among them, the material compositions of Table 1 and Table 2 are as follows:

[0047] Component A1 is recycled PET, and the intrinsic viscosity of PET is 0.80 dl / g;

[0048] Component A2 is recycled PET, and the intrinsic viscosity of PET is 0.65 dl / g;

[0049] Component B1 is ABS, butadiene content 55%, commercially available;

[0050] Component B2 is ABS, butadiene content 25%, commercially available;

[0051] Component C1 is a long-chain toughening agent, EMA-GMA, commercially available;

[0052] Component C2 is a long-chain toughening agent, EMA, commercially available;

[0053] Component C3 is a long-chain toughening agent, SEBS, commercially available;

[0054] Component C4 is a long-chain toughening agent, POE-g-MAH, commercially available;

[0055] Component D1 is a compatibilizer, SAG, commercially available;

[0056] Component D2 is a compatibilizer, SAN-MAH, commercially available;

[0057] Component D3 is a compatibilizer, SEBS-MAH, commercially available;

[0058] Component E is a phosphite antioxidant A mixture of 168 and hindered phenol IRGANOX 1076 in a weight ratio of 1:1;

[0059] Component F is a lubricant, EVA wax, which is commercially available.

[0060] Pull-out force test: The particle material prepared by the above method is dried in a blast oven at 120°C for 6 hours, and then the dried particles are injection molded on an injection molding machine to prepare a sample, and the sample size is 60mm×10mm×2.0mm; the two sample strips are connected end to end and welded with ultrasonic welding equipment, and the welding process conditions are: welding time 0.6s, welding pressure 10N, ultrasonic amplitude 60μm. After the sample strip is cooled for 24 hours, the two welded connected sample strips are clamped with one end of the fixture of the universal tensile testing machine, and the maximum tensile force of the pull-out force test is used to characterize the ultrasonic welding strength.

[0061] Table 1 Specific proportions (parts by mass) of the embodiments and comparative examples and their performance test results

[0062]

[0063] In the examples and comparative examples, the ultrasonic welding pull-out force of the high-viscosity PET resin is the largest. When the low-viscosity PET is added, the notched impact strength of the material is greatly reduced, and at the same time, the pull-out force after ultrasonic welding also decreases.

[0064] In the embodiments and comparative examples, the notched impact strength of ABS with low rubber powder content is greatly reduced, and at the same time, the pull-out force after ultrasonic welding is also reduced.

[0065] In the examples and comparative examples, the long-chain toughening agents C1 and C2 can improve the surface polarity of the material while achieving the toughening effect, and the pull-out force after ultrasonic welding is significantly improved. Comparing the long-chain toughening agents C1 and C2 at the same addition amount, the long-chain toughening agents C3 and C4 significantly reduce the impact strength, and the ultrasonic welding pull-out force is lower.

[0066] In the examples and comparative examples, the reactive compatibilizers D1 and D2 can achieve significant volume expansion effects at lower ratios, and D3 needs to achieve volume expansion effects at higher ratios. In the comparative example, no compatibilizer is added, and the impact strength and ultrasonic welding are low, but ultrasonic welding can be achieved, and the impact strength is also relatively high. However, adding a compatibilizer will further improve ultrasonic welding and toughness, and it is believed that the compatibilizer is also very important.

[0067] In the examples and comparative examples, lubricant F has a negative effect on ultrasonic welding and should not be added.

[0068] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A recycled PET / ABS alloy with high ultrasonic welding strength and high toughness, characterized in that: The composition comprises the following components in parts by weight: The long-chain toughening agent includes one or more of EMA and EMA-GMA.

2. The recycled PET / ABS alloy according to claim 1, characterized in that: The average intrinsic viscosity of the recycled PET is 0.70-0.85 dL / g.

3. The recycled PET / ABS alloy according to claim 1, characterized in that: In the recycled PET / ABS alloy with high ultrasonic welding strength and high toughness, the mass percentage of recycled PET exceeds 70%.

4. The recycled PET / ABS alloy according to claim 1, characterized in that: ABS is 15-20 parts; And / or, the long-chain toughening agent is 5-8 parts.

5. The recycled PET / ABS alloy according to claim 1, characterized in that: The ABS is a styrene-acrylonitrile-butadiene copolymer, wherein the butadiene content is 40-55%.

6. The recycled PET / ABS alloy according to claim 1, characterized in that: The long-chain toughening agent is EMA-GMA.

7. The recycled PET / ABS alloy according to claim 1, characterized in that: The compatibilizer is one or more of SAG, SAN-MAH and SBS-MAH.

8. The recycled PET / ABS alloy according to claim 1, characterized in that: The antioxidant is one or more of hindered phenol antioxidants and phosphite antioxidants.

9. A method for preparing the recycled PET / ABS alloy plastic as claimed in claim 1, the method specifically comprising the following steps: (1) Prepare the ingredients by weight: (2) After the components in step (1) are fully mixed, they are placed in a screw machine and extruded into granules to produce a PET / ABS alloy resin with a high recycling ratio that can be ultrasonically welded.

10. The preparation method according to claim 9, characterized in that: The temperature of extrusion granulation is 230-245°C.

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