Low-melting-point modified polyester material and forming method thereof

Abstract

The invention provides a low-melting-point modified polyester material. The low-melting-point modified polyester material is prepared from 50-70 parts of PET crushed reclaimed materials, 10-25 parts of dihydric alcohol, 0.01-0.5 part of a catalyst and 0.01-2 parts of a cross-linking agent, the forming method comprises the following five steps: drying treatment, preparation of a prefabricated material I, preparation of a prefabricated material II, mixing preparation and preparation of a finished product: drying treatment is performed on a PET crushed regenerated material, so that most moisture is removed, the moisture content is controlled, and the yield is high; the melting point of the polyester material is reduced, the formula is simple, the thermal stability of the product is not influenced, and the problems that the existing product material is fragile and cannot be normally used are solved.

Description

Technical Field

[0001] The invention relates to the technical field of preparation of low-melting-point modified polyester materials, in particular to a low-melting-point modified polyester material and a molding method thereof. Background Art

[0002] Polyethylene terephthalate (PET), with the chemical formula (C10H8O4)n, is obtained by ester exchange of dimethyl terephthalate with ethylene glycol or esterification of terephthalic acid with ethylene glycol to synthesize dihydroxyethyl terephthalate, followed by polycondensation. It is a crystalline saturated polyester, a milky white or light yellow, highly crystalline polymer with a smooth and glossy surface. It is a common resin in life.

[0003] According to a new study released by PET Recycling Team GmbH, a wholly owned subsidiary of ALPLA in Germany, the use of recycled PET (rPET) materials can reduce carbon dioxide emissions by 79% compared to the use of raw materials. The GmbH team has been engaged in research in the field of recycled PET for more than 20 years, and they found that the use of rPET materials reduces greenhouse gas emissions far more than they expected. The carbon emissions per kilogram of rPET produced by PET Recycling Team GmbH are 0.45 kilograms, while the carbon emissions per kilogram of PET raw materials are 2.15 kilograms, a reduction of nearly 79%. (Carbon emissions are calculated according to ISO 14044 standards.)

[0004] PET is made of polyethylene terephthalate (PET), which is a 100% highly recyclable material with a wide range of sources, such as bottled water bottles, food packaging bottles, clothing fabric fibers, etc. The existing PET recycled materials absorb water due to long-term contact with air, and the direct extrusion granulation chain breaks and degrades seriously, making the material brittle and unable to be used normally. Summary of the invention

[0005] In view of the above problems, the present invention discloses a low melting point modified polyester material and a molding method thereof.

[0006] The specific technical solutions are as follows:

[0007] A method for molding a low-melting-point modified polyester material comprises the following steps:

[0008] S1. Drying: Dry the PET crushed and recycled materials at a temperature of 85-140°C and a drying time of 1-4 hours to control the moisture content;

[0009] S2. Preparation of prefabricated material 1: PET crushed and recycled materials are processed by a twin-screw extruder. The PET crushed and recycled materials are sheared and broken by mechanical force and hydrolyzed and broken by a trace amount of water in the first zone of the twin-screw. At this time, a small amount of chain breaking occurs in the PET crushed and recycled materials, forming prefabricated material 1;

[0010] S3, preparation of prefabricated material 2: PET crushed and recycled material is processed through a small twin-screw extruder, melted and extruded, and input into a high-temperature melt glue device, and then diol is added, alcoholysis and transesterification reaction is carried out under nitrogen protection, and a catalyst is added, and vacuum treatment is carried out to form part of prefabricated material 2;

[0011] S4, mixing preparation: conveying the prepared part of the prefabricated material 2 into the twin-screw extruder in S2, and blending it with the prefabricated material 1, the blending zone is the second zone of the twin-screw;

[0012] S5. Finished product preparation: The mixed material is conveyed to the third zone by a twin-screw extruder. A cross-linking agent feeding device is provided at the front section of the third zone. After the cross-linking agent is added, the chain-breaking free radicals are quickly captured and a chain extension reaction occurs, thereby achieving molecular block modification of the PET material, destroying the rigid molecular regularity, and lowering the melting point. A vacuum treatment is performed in this area to obtain a low-melting-point modified polyester material.

[0013] Preferably, the high temperature melt device is a kettle or box type device;

[0014] Preferably, the diol is 1,4-butanediol or pentanediol;

[0015] Preferably, the crosslinking agent is a multifunctional crosslinking agent, such as trifunctional epoxy resin, tetrafunctional epoxy resin, pyromellitic anhydride, BASF ADR-4380 chain extender, epoxy resin E51, modified solid epoxy resin powder B17, B19, phenoxy resin B1100 (containing hydroxyl groups), etc.

[0016] A low melting point modified polyester material comprises 50-70 parts of PET crushed and recycled materials, 10-25 parts of diols, 0.01-0.5 parts of catalysts and 0.01-2 parts of crosslinking agents.

[0017] The beneficial effects of the present invention are:

[0018] The invention provides a low-melting-point modified polyester material and a molding method thereof, including drying treatment, prefabricated material preparation one, prefabricated material preparation two, mixed preparation and finished product preparation, five major steps: by drying the PET crushed and recycled materials, most of the water vapor therein is removed, the moisture content is controlled, and the yield of the finished product is high; the melting point of the polyester material is lowered, the formula is simple, and the thermal stability of the product is not affected, thus overcoming the problem that the existing product materials are brittle and cannot be used normally. DETAILED DESCRIPTION

[0019] In order to make the technical solution of the present invention clearer and more specific, the present invention is further described below in conjunction with embodiments. Any equivalent replacement of the technical features of the technical solution of the present invention and any solution derived by conventional reasoning shall fall within the protection scope of the present invention.

[0020] A method for molding a low-melting-point modified polyester material comprises the following steps:

[0021] S1. Drying: Dry the PET crushed and recycled materials at a temperature of 85-140°C and a drying time of 1-4 hours to control the moisture content;

[0022] S2. Preparation of prefabricated material 1: PET crushed and recycled materials are processed by a twin-screw extruder. The PET crushed and recycled materials are sheared and broken by mechanical force and hydrolyzed and broken by a trace amount of water in the first zone of the twin-screw. At this time, a small amount of chain breaking occurs in the PET crushed and recycled materials, forming prefabricated material 1;

[0023] S3, preparation of prefabricated material 2: PET crushed and recycled material is processed through a small twin-screw extruder, melted and extruded, and input into a high-temperature melt glue device, and then diol is added, alcoholysis and transesterification reaction is carried out under nitrogen protection, and a catalyst is added, and vacuum treatment is carried out to form part of prefabricated material 2;

[0024] S4, mixing preparation: conveying the prepared part of the prefabricated material 2 into the twin-screw extruder in S2, and blending it with the prefabricated material 1, the blending zone is the second zone of the twin-screw;

[0025] S5. Finished product preparation: The mixed material is conveyed to the third zone by a twin-screw extruder. A cross-linking agent feeding device is provided at the front section of the third zone. After the cross-linking agent is added, the chain-breaking free radicals are quickly captured and a chain extension reaction occurs, thereby achieving molecular block modification of the PET material, destroying the rigid molecular regularity, and lowering the melting point. A vacuum treatment is performed in this area to obtain a low-melting-point modified polyester material.

[0026] Embodiment 1:

[0027] The modified polyester material can be further toughened and modified. HDPE polyethylene, polyethylene octene co-elastomer, ethylene-vinyl acetate copolymer, ethylene acrylic acid copolymer, ethylene-ethyl acrylic acid copolymer, ethylene-methacrylic acid copolymer, EPDM rubber, EPDM rubber, nitrile rubber, polypropylene, bio-based fatty polyether amide, polyester amide, POE, etc. can be added in the subsequent fourth zone of the twin-screw extruder. Some of these materials are polar materials themselves, and non-polar materials such as polypropylene and POE need to be grafted with functional groups such as MAH and GMA to improve the compatibility of these materials with polyester modified materials.

[0028] Embodiment 2:

[0029] A porous silica-alumina microbead can be added to fill and modify the material. After the inorganic material porous silica-alumina microbead is surface treated with a coupling agent (the coupling agent can be a silane coupling agent KH550, a titanate coupling agent, stearic acid, etc.) to introduce functional groups, it can be blended with the polyester material to improve impact resistance, bending, and dimensional stability.

[0030] The porous silica-alumina microbeads are prepared as follows: the porous silica-alumina microbeads (including solid and hollow microbeads) are subjected to thermal phase separation at 600° C. in a heating furnace, and then immersed in low-solubility hydrochloric acid after cooling, and the liquid temperature is controlled at 85-95° C. to accelerate the acid etching of the silica-alumina microbeads by hydrochloric acid, remove components such as iron oxide and aluminum oxide, and obtain porous aluminum microbeads after washing, neutralization and drying. Pure silica porous microbeads can be obtained by thorough acid etching, and porous microbeads mainly composed of silica and aluminum oxide can be obtained by partial acid etching.

[0031] The surface treatment methods of the porous microbeads include: high-speed mixing, soaking in a hydrolysis solution and then drying, radiation cross-linking, and ultraviolet light initiation to introduce functional groups / chains onto the surface of the microbeads.

[0032] The invention provides a low melting point modified polyester material, including 50-70 parts of PET crushed recycled material, 10-25 parts of diol, 0.01-0.5 parts of catalyst and 0.01-2 parts of cross-linking agent; its molding method includes drying treatment, prefabricated material preparation one, prefabricated material preparation two, mixed preparation and finished product preparation, five steps: by drying the PET crushed recycled material, most of the water vapor therein is removed, the moisture content is controlled, and the yield of the finished product is high; the melting point of the polyester material is reduced, the formula is simple, the thermal stability of the product is not affected, and the problem that the existing product material is brittle and cannot be used normally is overcome.

[0033] Obviously, the content currently described in this patent is not all the embodiments, but only a small part of the embodiments in the patent of this invention. Based on the embodiments in this invention, the results obtained by other technical personnel, companies, and social groups in this field without creative labor are all within the scope of protection of this patent.

[0034] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for molding a low melting point modified polyester material, characterized in that it comprises the following steps: S1. Drying: Dry the PET crushed and recycled materials at a temperature of 85-140°C and a drying time of 1-4 hours to control the moisture content; S2. Preparation of prefabricated material 1: PET crushed and recycled materials are processed by a twin-screw extruder. The PET crushed and recycled materials are sheared and broken by mechanical force and hydrolyzed and broken by a trace amount of water in the first zone of the twin-screw. At this time, a small amount of chain breaking occurs in the PET crushed and recycled materials, forming prefabricated material 1; S3, preparation of prefabricated material 2: PET crushed and recycled material is processed through a small twin-screw extruder, melted and extruded, and input into a high-temperature melt glue device, and then diol is added, alcoholysis and transesterification reaction is carried out under nitrogen protection, and a catalyst is added, and vacuum treatment is carried out to form part of prefabricated material 2; S4, mixing preparation: conveying the prepared part of the prefabricated material 2 into the twin-screw extruder in S2, and blending it with the prefabricated material 1, the blending zone is the second zone of the twin-screw; S5. Finished product preparation: The mixed material is conveyed to the third zone by a twin-screw extruder. A cross-linking agent feeding device is provided at the front section of the third zone. After the cross-linking agent is added, the chain-breaking free radicals are quickly captured and a chain extension reaction occurs, thereby achieving molecular block modification of the PET material, destroying the rigid molecular regularity, and lowering the melting point. A vacuum treatment is performed in this area to obtain a low-melting-point modified polyester material.

2. A method for molding a low melting point modified polyester material as claimed in claim 1, characterized in that: The high temperature melt glue device is a kettle or box type device.

3. A method for molding a low melting point modified polyester material as claimed in claim 1, characterized in that: The diol is 1,4-butanediol or pentanediol.

4. A method for molding a low melting point modified polyester material as claimed in claim 1, characterized in that: The crosslinking agent is a multifunctional crosslinking agent, which can be a trifunctional epoxy resin, a tetrafunctional epoxy resin, pyromellitic anhydride, BASF ADR-4380 chain extender, epoxy resin E51, modified solid epoxy resin powder B17, B19 or phenoxy resin B1100 (containing hydroxyl group), etc.

5. A low melting point modified polyester material, characterized in that: The method comprises 50-70 parts of PET crushed and recycled materials, 10-25 parts of diols, 0.01-0.5 parts of catalysts and 0.01-2 parts of cross-linking agents.