WO2023045268A1 - Preparation method of hly-active tackifying chain extender without monomer residue and use thereof - Google Patents

Abstract

Provided are a preparation method of a highly-active tackifying chain extender without monomer residue and the use thereof; the preparation method comprises the following steps: mixing an aromatic vinyl monomer, an acrylate-based monomer and an initiator with a solvent or water, carrying out heating polymerization, and then carrying out double-screw secondary reaction granulation to prepare the tackifying chain extender without monomer residue. The epoxy functionalized chain extender of the present invention can be applied to recycled polyester structural materials, and can be applied to the repair and growth of bio-based and biodegradable plastic molecular chains with polyester structures. The present invention is simple in terms of control over the selected process and low in investment, and the product is stable in composition, simple to use and widely applicable in the fields of medical treatment, packaging, household appliances, automobiles and the like. The present invention has very broad application prospects and industrial values.

Description

Preparation method and application of highly active viscosity-increasing chain extender without monomer residue technical field

The invention belongs to the field of macromolecular materials, and relates to a preparation method and application of a high-activity viscosity-increasing chain extender without monomer residues, in particular to a viscosity-increasing and chain-extending agent that can be used for degradable polyester and recycled polyester Agents and their preparation methods and applications.

Background technique

At present, the global demand for biodegradable plastics is also showing a rapid growth trend. It is expected to reach 3.5 million tons by 2021, with an average annual growth rate of 16.7%. Among them, Europe has the largest demand, accounting for 31%, North America and China account for 28% and 20% respectively. And my country will also gradually implement the plastic restriction order. The National Development and Reform Commission and the Ministry of Ecology and Environment recently issued the "Opinions on Further Strengthening Plastic Pollution Control", clearly following the idea of "prohibiting and limiting one batch, replacing a batch of recycling, and standardizing a batch". main task. Therefore, my country's biodegradable material market will gradually expand. It can be seen that low-carbon, recycling, environmental protection, and sustainable development are the major themes and trends of world development. The recycling and degradability of plastics will attract more and more attention and develop into a specific industry. In plastic recycling technology, it is very important to restore material properties and improve its functionality so that it can be processed and utilized multiple times. The chain extender is the key technical point of turning waste into treasure and turning stone into gold in the recycling process.

In the early days, the use of isocyanate chain extension was widely used in the synthesis of polylactic acid biodegradable polymer materials. Many biheterocyclic compounds containing N and O can also be used in chain extension reactions, among which bisoxazolines are the most common. So far, the research on chain extenders also includes epoxy-functionalized polymers and maleic anhydride-functionalized polymers, among which the development and application of epoxy-functionalized polymer chain extenders has attracted the most attention. The current research and development of chain extenders focus on epoxy functional polymers. At present, the epoxy polymer chain extenders in the domestic market are mainly Joncryl ADR series from BASF, and Cesa‑extend series from Clariant. Masterbatch, TN4300 from Shanghai Antelope Chemical Co., Ltd., KL‑E series from Shanxi Research Institute of Chemical Industry. However, the existing chain extenders have high monomer residues, and the residual monomers are small molecules, which are easy to migrate and precipitate in the material, and are more toxic to the human body than polymers, so they are not suitable for food contact applications. For example, food-grade applications such as drinking straws and biodegradable tableware need to minimize the residue of monomers to ensure the maximum safety of food. The Food Contact Materials, Enzymes and Processing Aids (CEP) Group of the European Food Safety Authority (EFSA) has published a report on the use of styrene in plastic food contact materials (FCM) in Volume 121 of the International Agency for Research on Cancer (IARC) Monograph Safety impact assessment report. In September 2019, IARC re-evaluated styrene and classified it as "possibly carcinogenic to humans" (category 2A). Based on this classification, the European Commission asked EFSA to reassess the safety of the use of styrene in plastic FCMs.

China's national food safety standards have very clear regulations on food material additives. If the additive is to be used in food contact materials, then the maximum usage amount of the additive, the specific migration amount or the maximum residual amount, and the total specific migration amount Certain requirements must be met. GB 9685-2016 Standards for the Use of Additives in Food Contact Materials and Products stipulates that the total residual QM of general epoxy additives in food contact materials is less than 6mg/kg. Existing chain extenders have a high concentration of residual monomers. At present, the methods for reducing residual monomers in production mainly include (1) in the late stage of polymerization reaction, prolonging the reaction time as much as possible and increasing the reaction temperature to reduce residual monomers, but time-consuming and energy-consuming. Body effect is not ideal. (2) Reactive extrusion and vacuum extraction. However, the residence time in the extruder is too short, and the monomer is wrapped by the melt, so it is difficult to escape from the melt.

technical problem

Aiming at the defects in the prior art, the object of the present invention is to provide a high-activity viscosity-increasing chain extender and its preparation method without monomer residue, which can be used for the application of degradable polymers and recycling. The use of the chain extender of the present invention can greatly reduce the residue of the chain extender monomer in the degradable resin or recycled materials while satisfying the chain extension performance, and reduce the toxicity of the monomer. In the conventional reaction of existing polymers, especially in the polycondensation reaction, it is difficult to remove small molecules in the late stage of the reaction, and the polymer sometimes does not reach the required relative molecular mass. Although a relatively high molecular weight can be obtained by using solid-state polycondensation, the The operation is cumbersome, the process is time-consuming, and the economic requirements cannot be met. The use of the chain extender of the present invention can quickly and effectively increase the molecular weight on the extruder within a few minutes.

technical solution

The purpose of the present invention is achieved through the following technical solutions: the present invention provides a highly active chain extender without monomer residue, which is prepared by a method comprising the following steps: After the monomer, acrylate monomer, primary initiator, molecular weight regulator and solvent or water are mixed, they are put into the polymerization reactor and heated for polymerization; , to prepare no monomer residue type viscosity-enhancing chain extender. As an embodiment of the present invention, the residue of the aromatic vinyl monomer and the residue of the acrylate monomer in the non-residual, highly active tackifying and chain extender are less than 100 ppm. As an embodiment of the present invention, the weight-average molecular weight of the high activity viscosity-increasing chain extender without monomer residue is 25000-150000. As an embodiment of the present invention, taking the mass sum of the aromatic vinyl monomer and the acrylate monomer as 100%, the mass percentage of the acrylate monomer is 25-65%. As an embodiment of the present invention, the amount of the first initiator is 0.1%-2% of the monomer mass sum. In some preferred embodiments, the amount of the first initiator is 0.1%-1.5% of the monomer mass sum. As an embodiment of the present invention, the amount of the secondary initiator is 0.05%-0.2% of the monomer mass sum.

As an embodiment of the present invention, the secondary initiator is selected from azo or peroxy initiators.

The secondary initiator is preferably selected from bis-369 (3,6,9-triethyl-3,6,9-trimethyl-1,4,7-tripperoxynonane, cas number 24748-23-0 ), or bis-25 (2,5‑dimethyl‑2,5‑bis‑(tert-butylperoxy)hexane, cas number 78‑63‑7).

As an embodiment of the present invention, the aromatic vinyl monomer is selected from at least one of styrene, α-methylstyrene monomer, α-chlorostyrene monomer, p-methylstyrene monomer kind.

As an embodiment of the present invention, the acrylate monomer is selected from glycidyl methacrylate or glycidyl methacrylate and methyl (meth)acrylate, ethyl (meth)acrylate, (meth)acrylate One or more mixtures of butyl acrylate, cyclohexyl (meth)acrylate, and octadecyl (meth)acrylate.

As an embodiment of the present invention, the first initiator is selected from azobisisobutyronitrile and azobisisoheptanonitrile.

As an embodiment of the present invention, the molecular weight regulator is selected from dodecyl mercaptan.

As an embodiment of the present invention, the amount of the molecular weight regulator is 0.25%-0.5% of the mass sum of the monomers.

In the present invention, the usable solvent is not particularly limited as long as it can dissolve the above-mentioned raw materials. For example, the solvent may include toluene, xylene.

As an embodiment of the present invention, the reaction temperature of the heating polymerization is 75°C-98°C, and the reaction time is 4-6 hours. It is preferred to react at 75°C for 4 hours, and then raise the temperature to 98°C to continue the reaction for 1 hour.

As an embodiment of the present invention, the reaction temperature of the secondary reaction is 185-195°C, and the reaction time is 15-25s. Preferably, the reaction temperature is 190° C., and the reaction time is 20 s.

The present invention also provides an application of the above-mentioned non-residual monomer and highly active viscosity-increasing chain extender as a chain extender in the preparation of polymers.

As an embodiment of the present invention, the polymer is a polyester polymer; the amount of the monomer-free, highly active viscosity-increasing chain extender is 0.3-1.5% of the quality of the raw material of the polyester polymer.

As an embodiment of the present invention, the non-residual monomer, high-activity viscosity-increasing chain extender is applied to recycled polyester structural materials, and is applied to repair molecular chains of bio-based and biodegradable plastics with polyester structure ,increase.

The use of conventional chain extenders to extend the chains of these two specific polyester materials has the problems of low reaction efficiency and high addition amount; however, the application of the chain extender of the present invention can achieve high reaction efficiency and low addition amount.

The present invention also provides a chain-extended polyester polymer. The preparation method of the chain-extended polyester polymer comprises the following steps: adjusting an aromatic vinyl monomer, an acrylate monomer, an initial initiator, a molecular weight After the agent and the solvent are mixed, they are put into the polymerization reactor to heat and polymerize. After the polymerization, the product and the secondary initiator are mixed again and subjected to twin-screw secondary reaction granulation to prepare a highly active viscosity-increasing chain extender without monomer residues; The polyester polymer is mixed with the monomer-free, high-activity viscosity-increasing chain extender and then extruded to obtain a chain-extended polyester polymer. In some embodiments, the granulation is carried out by twin-screw under the condition of 140-210°C.

Beneficial effect

Compared with the prior art, the present invention has the following beneficial effects: 1. The monomer residue in the chain extender of the present invention is low, and can be applied to high-end applications related to medical equipment and food and drug packaging; 2. The chain extender of the present invention The chain agent belongs to polymer, has high thermal stability, high softening point, and is easy to feed materials. It can be applied to various processing techniques and conditions, and avoids the problem of softening and caking or equipment selectivity in the production process; 3. The chain extension of the present invention The agent has a wide range of uses: it can be applied to polylactic acid (PLA), copolymer of butylene adipate and butylene terephthalate (PBAT), polypropylene carbonate (PPC), etc. The repair, growth and crosslinking of molecular chains of bio-based and biodegradable plastics are effective as well as for recycled polycarbonate (PC), polyethylene terephthalate (PET), polybutylene terephthalate Polyester structural materials such as alcohol ester (PBT) have the effect of chain extension regeneration.

Description of drawings

By reading the detailed description of non-limiting examples with reference to the following drawings, other features, purposes and points of the present invention will become more apparent: FIG. 1 is a schematic diagram of TGA analysis of Example 1 and Comparative Example 5.

Embodiments of the present invention

The present invention will be described in detail below in conjunction with specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

The test conditions are as follows: weight-average molecular weight (Mw): take PS as the standard sample, and adopt GPC test; RTVM (residual monomer): test according to ASTM D790 standard, adopt GC-MS; thermal weight loss: carry out according to ASTM D6370-99 standard The test adopts TGA; melt index: the test is carried out according to ASTM D1238 standard, and the test condition is 270°C*2.16kg.

Table 1 The formula table of the embodiment and the comparative example, parts by mass.

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The preparation process in Table 1 is as follows: 1. styrene, glycidyl methacrylate GMA, primary initiator azobisisobutyronitrile, molecular weight regulator dodecyl mercaptan and 200 parts by mass of deionized water in a reactor Mix, react at 75°C for 4 hours under normal stirring, then raise the temperature to 98°C to continue the reaction for 1 hour, then discharge the material in the discharge tank, after conventional filtration, dry the obtained particles at 85°C to constant weight, and then mix with two After the secondary initiator Shuang 369 is mixed, it is added to a twin-screw extruder, extruded and granulated at 190°C to obtain a chain extender; the aspect ratio of the twin-screw extruder is 35, and it has multi-stage vacuum.

② Mix styrene, glycidyl methacrylate GMA, primary initiator azobisisobutyronitrile, molecular weight modifier dodecyl mercaptan and 200 parts by mass of deionized water in a reactor, and mix them under conventional stirring for 75 ℃ to react for 4 hours, then raise the temperature to 98℃ to continue the reaction for 1 hour, then discharge the material in the discharge tank, after conventional filtration, dry the obtained particles at 85℃ to constant weight, add to the twin-screw extruder, 190℃ Extrude and granulate to obtain a chain extender; the aspect ratio of the twin-screw extruder is 35, and the multi-stage vacuum is used.

③Mix styrene, GMA, initiator azobisisobutyronitrile, molecular weight regulator dodecyl mercaptan and 200 parts by mass of deionized water in a reaction kettle, react at 85°C for 7 hours under conventional stirring, and then heat up Continue to react at 110°C for 2 hours, then discharge the material in the discharge tank, and after conventional filtration, dry the obtained particles at 95°C to constant weight to obtain a chain extender; the aspect ratio of the twin-screw extruder is 35, With multi-stage vacuum.

④ put styrene, glycidyl methacrylate GMA, initial initiator azobisisobutyronitrile, secondary initiator double 369, molecular weight modifier dodecyl mercaptan and 200 parts by mass of deionized water in a reactor Mix, react at 75°C for 4 hours under normal stirring, then raise the temperature to 98°C and continue to react for 1 hour.

⑤ Put styrene, glycidyl methacrylate GMA, primary initiator azobisisobutyronitrile, secondary initiator double 369, molecular weight modifier dodecyl mercaptan and 200 parts by mass of deionized water in a reactor Mix, react at 75°C for 4 hours under conventional stirring, then raise the temperature to 98°C to continue the reaction for 1 hour, then discharge the material in the discharge tank, after conventional filtration, dry the obtained particles at 85°C to constant weight; add twin-screw In the extruder, extrude and granulate at 190°C to obtain the chain extender; the aspect ratio of the twin-screw extruder is 35, and has multi-stage vacuum.

Table 2 shows the molecular weight and residual monomers of Examples 1-3 and Comparative Examples 1-5 mentioned above.

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The result of table 2 shows, because first initiator and chain transfer of embodiment 1-3 and comparative example 1-5 are corresponding relationship, so molecular weight is corresponding relationship substantially. However, due to the adoption of different secondary granulation processes, the residual monomers in the examples and the comparative examples are very different. The residual monomers in the examples are all very low, while the residual monomers in Comparative Example 1-5 belong to the residual monomers contained in normal particles, and the residual monomer concentration is very high.

Fig. 1 is the TGA analysis comparison of Example 1 and Comparative Example 5. The result of Fig. 1 shows: the thermal stability of embodiment 1 is much better than comparative example 5, because there is a large amount of small molecular monomers in comparative example 5, so when heat loss 1%, temperature is 172 ℃, and embodiment 1 is due to Contains less residual monomer, so when the thermal weight loss is 1%, the temperature is 310.7°C. This figure not only illustrates that the thermal stability of Example 1 (the TGA of the remaining examples is almost the same, and the same thermal stability is good) is better than Comparative Example 5, according to the existing chain extender ADR series report, the molecular weight of the ADR series Below 10,000, the temperature for thermal weight loss of 5% is 290°C. Polymer materials, from the perspective of molecular chain structure, are composed of many small molecules connected hand in hand one by one. Generally, those with a molecular weight greater than 10,000 are called polymer materials. Therefore, the polymer material of the present invention has high thermal stability and less residual monomer, and can be applied to food-related contact materials.

Application evaluation chain extension effect test: Example 1-3 and Comparative Example 1-5 were respectively used as chain extenders and polylactic acid at 140-210°C to granulate through high-vacuum twin-screws. Specifically, the chain extender and PLA are added to the twin-screw extruder (the amount of the chain extender is 0.8% of the polylactic acid), and under the condition of 140-210°C, the twin-screw is granulated to obtain polymer particles; The resulting particles were tested for melt index (MI), residual monomer content. The test results are shown in Table 3.

Table 3 Example 1-3 and Comparative Example 1-5 were tested after chain extender and polylactic acid granulation (residual single detection limit is 1ppm. Below 1ppm is ND).

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The experimental result of table 3 shows: embodiment 1-3 is very obvious to the melt index reduction effect of PLA, illustrates that the chain extender prepared by embodiment 1-3 has the characteristics of high activity, and polylactic acid has been efficiently chain-extended and branching reaction. Comparative Example 1-5 also has very high chain extension activity due to the same monomer ratio as that of Example 1. From the test results of residual monomers, it is shown that the residual styrene monomers and residual acrylate monomers of Example 1-3 are all undetected NDs in the instrument test. However, the residual styrene and acrylate monomers in Comparative Example 1-5 were greater than 10 ppm. High monomer residue has certain toxicity to food contact packaging bags or tableware, so it should be used with caution.

Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention.

Claims (10)

A kind of no monomer residue, highly active viscosity-increasing chain extender, it is characterized in that, described chain extender is prepared by the method comprising the following steps: S1. Mix aromatic vinyl monomers, acrylate monomers, primary initiators, molecular weight modifiers with solvents or water, and put them into a polymerization reactor to heat and polymerize; S2. After the polymerization is completed, the product and the secondary initiator are mixed again and subjected to twin-screw secondary reaction granulation to prepare a high-activity viscosity-increasing chain extender without monomer residue. No monomer residue according to claim 1, high activity viscosity-increasing chain extender, it is characterized in that, the residue of aromatic vinyl monomer in the described no monomer residue, high activity viscosity-increasing chain extender is less than 100ppm, The residue of acrylate monomer is less than 100ppm; the weight-average molecular weight of the high activity viscosity-increasing chain extender without monomer residue is 25000-150000. No monomer residue according to claim 1, high activity viscosity-increasing chain extender, characterized in that, the mass sum of aromatic vinyl monomers and acrylate monomers is 100%, wherein the acrylate monomers The mass percent is 25-65%; the amount of the initial initiator is 0.1%-2% of the total monomer mass. The non-monomer residue, high activity viscosity-increasing chain extender according to claim 3, characterized in that the amount of the primary initiator is 0.1%-1.5% of the total mass of monomers. The non-monomer residue, high-activity viscosity-increasing chain extender according to claim 1, wherein the amount of the secondary initiator is 0.05%-0.2% of the total mass of the monomers. The non-residual monomer and highly active viscosity-increasing chain extender according to claim 1, wherein the secondary initiator is selected from azo or peroxy initiators. No monomer residue according to claim 6, high activity viscosity-increasing chain extender, it is characterized in that, described secondary initiator is preferably selected from 3 ,6 ,9‑triethyl‑3 ,6 ,9‑trimethyl‑1 ,4 ,7‑triperoxynonane or 2 ,5‑dimethyl‑2 ,5‑bis‑(tert-butylperoxynonane Oxygen) hexane. No monomer residue according to claim 1, high activity viscosity-increasing chain extender, it is characterized in that, described acrylate monomer is selected from glycidyl methacrylate or glycidyl methacrylate and (methacrylic acid ester) One or more mixtures of methyl acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, cyclohexyl (meth)acrylate, and octadecyl (meth)acrylate. A kind of non-monomer residue as described in any one in claim 1-8, the application of highly active viscosity-increasing chain extender as chain extender in preparing polymer. The application according to claim 9, characterized in that, the polymer is a polyester polymer; the amount of the non-monomer residue, highly active viscosity-increasing chain extender is 0.3-3% of the raw material quality of the polyester polymer. 1.5%.