Compatible modified resin, preparation method of compatible modified resin, polyolefin / aliphatic polycarbonate alloy material and application of polyolefin / aliphatic polycarbonate alloy material

Abstract

The invention relates to compatible modified resin, a preparation method thereof, a polyolefin / aliphatic polycarbonate alloy material and application thereof, and belongs to the technical field of packaging materials. The preparation method comprises the steps that aliphatic polycarbonate and diisocyanate are plasticized and mixed, an isocyanate-terminated group is grafted to the aliphatic polycarbonate to obtain an intermediate, and the concentration of the isocyanate-terminated group in the intermediate is larger than or equal to 10 mol / t. Polyolefin grafted glycidyl methacrylate with the grafting rate larger than or equal to 0.5% is mixed with the intermediate, an epoxy group in the polyolefin grafted glycidyl methacrylate reacts with an isocyanate-terminated group in the intermediate, the compatible modified resin is obtained, the concentration of the isocyanate-terminated group in the compatible modified resin is smaller than or equal to 1.5 mol / t, and the compatibility modified resin is obtained. The residual grafting rate of the compatible modified resin is less than or equal to 0.15%. According to the compatible modified resin obtained by the method, the compatibility of aliphatic polycarbonate and polyolefin can be improved, and the oxygen barrier effect is better.

Description

Technical Field

[0001] The present application relates to the technical field of packaging materials, and in particular to a compatible modified resin and a preparation method thereof, a polyolefin / aliphatic polycarbonate alloy material and applications thereof. Background Art

[0002] Food packaging is mainly to separate food from the outside environment through packaging materials to ensure food quality and extend its shelf life. Therefore, packaging materials need to have a good ability to block the infiltration of oxygen, water vapor, carbon dioxide, etc. in the environment. Compared with traditional food packaging materials such as paper, metal, and glass, although polymer materials (especially plastics) have only been used in the field of food packaging for nearly a hundred years, they have always been a popular food packaging material due to their advantages in comprehensive performance such as barrier properties, price, density, processing and transparency.

[0003] To date, it is time-consuming and laborious to develop a new monomer polymer to meet the high barrier requirements of food packaging materials. In order to minimize the R&D costs and keep the R&D cycle up to date with the update of food packaging materials, polymers with different properties can be compounded together. According to the similar compatibility theory, non-polar monomer polymers such as PE (Polyethylene) and PP (Polypropylene) have good barrier properties to polar small molecules such as water vapor, but poor barrier properties to non-polar small molecules such as oxygen, while polar polymers such as APC (aliphatic polycarbonate prepared by copolymerization of carbon dioxide and alkylene oxide) and EVOH (ethylene-vinyl alcohol copolymer) have good barrier properties to non-polar gases, but poor barrier properties to polar small molecules. When two or more polymers are simply compounded together, the barrier properties of the material are greatly increased.

[0004] Since the 1990s, the development of blending modification technology has gradually matured and has become a major trend in the development of modern material processing technology. By blending polymers with different properties, the different characteristics of the polymers are optimized and combined into one (the continuous phase is polyolefin, and the polymers with high barrier properties are distributed in it), and the blended modified polymers with excellent performance can be obtained to meet the comprehensive requirements of barrier properties and mechanical properties of packaging materials. PE and PP are the simplest molecules in resins. They are abundant in source, low in price, stable in chemical properties, and easy to process and shape; APC has excellent gas barrier properties, resistance to organic solvents, and easy printing. Therefore, the blended polymer uses PE and PP as the continuous phase and APC as the dispersed phase. However, PE and PP are non-polar resins, APC is a polar resin, and the compatibilizer of the blended polar / non-polar resins is low, so that the oxygen barrier performance of the blended polymer is not high. Summary of the invention

[0005] In view of the deficiencies in the prior art, the purpose of the embodiments of the present application includes providing a compatible modified resin and a preparation method thereof, a polyolefin / aliphatic polycarbonate alloy material and an application thereof, so as to improve the compatibility of the polyolefin / aliphatic polycarbonate alloy material and make it have better oxygen barrier performance.

[0006] In the first aspect, the embodiment of the present application provides a method for preparing a compatible modified resin for a polyolefin / aliphatic polycarbonate alloy, comprising: plasticizing and mixing an aliphatic polycarbonate with a diisocyanate, grafting an end isocyanate group onto the aliphatic polycarbonate to obtain an isocyanate group-terminated modified aliphatic polycarbonate intermediate, and the concentration of the end isocyanate group in the intermediate is ≥10 mol / t. A polyolefin grafted methacrylate glycidyl ester having a grafting rate ≥0.5% is mixed with the intermediate, and the epoxy group in the polyolefin grafted methacrylate glycidyl ester reacts with the end isocyanate group in the intermediate to obtain a compatible modified resin, and the concentration of the end isocyanate group in the compatible modified resin is ≤1.5 mol / t, and the residual grafting rate of the compatible modified resin is ≤0.15%.

[0007] In the above technical scheme, when the isocyanate group-terminated modified aliphatic polycarbonate intermediate (the concentration of the terminal isocyanate group in the intermediate is ≥10 mol / t) reacts with polyolefin grafted methacrylate glycidyl (grafting rate ≥0.5%), the terminal isocyanate group concentration and the polyolefin grafting rate are relatively reasonable, the reaction activity is high, the effective collision probability of the isocyanate group and the epoxy group is high, the reaction degree is high, and the raw materials are fully reacted to obtain a compatible modified resin with a terminal isocyanate group concentration of ≤1.5 mol / t and a grafting rate of ≤0.15%, indicating that the compatible modified resin contains more PO-g-APC, so as to subsequently improve the oxygen barrier performance of the alloy material. When the terminal isocyanate group concentration of the intermediate and the grafting rate of PO-g-GMA are too low, the effective collision probability of the terminal isocyanate group and the GMA group is low, and the reaction degree is also low.

[0008] In some embodiments of the present application, the terminal hydroxyl concentration of the aliphatic polycarbonate used to prepare the compatible modified resin is ≥32 mol / t; optionally, the terminal hydroxyl concentration of the aliphatic polycarbonate is 32-60 mol / t. The higher the terminal hydroxyl concentration of the aliphatic polycarbonate, the easier it is to graft the terminal isocyanate group to facilitate the subsequent reaction to prepare the compatible modified resin. Generally, an aliphatic polycarbonate with a terminal hydroxyl concentration of ≤60 mol / t for the compatible modified resin should be selected, otherwise it will affect the material processing.

[0009] In some embodiments of the present application, the diisocyanate includes at least one of toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), dicyclohexylmethane diisocyanate (HMDI), hexamethylene diisocyanate (HDI), and lysine diisocyanate (LDI).

[0010] In some embodiments of the present application, the molar ratio of aliphatic polycarbonate to diisocyanate is 100: 1-100: 3. The molar ratio is selected to react in a suitable range to obtain an intermediate having a terminal isocyanate group concentration of ≥ 10 mol / t (the intermediate is an aliphatic polycarbonate end-modified with isocyanate groups).

[0011] The molar ratio of polyolefin grafted glycidyl methacrylate to the intermediate should be adjusted adaptively according to the grafting rate of polyolefin grafted glycidyl methacrylate and the concentration of terminal isocyanate groups of the intermediate, so that the terminal isocyanate groups of the intermediate can fully react to obtain a compatible modified resin, and the concentration of the terminal isocyanate groups in the compatible modified resin is ≤1.5 mol / t, and the residual grafting rate of the compatible modified resin is ≤0.15%. In this way, sufficient PO-g-APC can be obtained, so that the obtained compatible modified resin has a better improvement effect on the compatibility of the polyolefin / aliphatic polycarbonate alloy material.

[0012] In some embodiments of the present application, the polyolefin grafted glycidyl methacrylate includes at least one of polyethylene grafted glycidyl methacrylate, polypropylene grafted glycidyl methacrylate, and poly-1-butene grafted glycidyl methacrylate.

[0013] In the second aspect, the present application provides a compatible modified resin prepared by the preparation method provided in any one of the first aspects, and the compatible modified resin is used for the compatibility modification of polyolefin / aliphatic polycarbonate alloy materials, which can make the compatibility of polyolefin and aliphatic polycarbonate better, so that the polyolefin / aliphatic polycarbonate alloy material has better oxygen barrier properties.

[0014] In the third aspect, the present application provides a polyolefin / aliphatic polycarbonate alloy material, which comprises, in parts by weight: 100 parts of an alloy resin base material and 2-5 parts by weight of a compatible modified resin provided in the second aspect, wherein the alloy resin base material comprises 75-95 parts by weight of a polyolefin and 5-25 parts by weight of an aliphatic polycarbonate.

[0015] In the above technical scheme, the compatible modified resin prepared by the preparation method provided in any one of the first aspects can make the compatibility of polyolefin and aliphatic polycarbonate better, so that the obtained polyolefin / aliphatic polycarbonate alloy material has better oxygen barrier properties and mechanical properties.

[0016] In some embodiments of the present application, the polyolefin includes at least one of polyethylene, polypropylene, poly-1-butene, and ethylene-butene copolymer. Such materials are commonly used packaging materials, and the appropriate material category can usually be selected according to the needs of the use scenario, and the appropriate specification of the material can be selected according to the processing and performance requirements.

[0017] In some embodiments of the present application, the selected aliphatic polycarbonate has a high molecular weight (weight average molecular weight is generally 15.0×10 4 -60.0×10 4 ), so the terminal hydroxyl concentration is ≤10 mol / t. The high molecular weight aliphatic polycarbonate has good oxygen barrier properties, and the obtained polyolefin / aliphatic polycarbonate alloy material has better oxygen barrier effect.

[0018] In some embodiments of the present application, the aliphatic polycarbonate is obtained by polymerization of carbon dioxide and alkylene oxide; optionally, the alkylene oxide includes at least one of ethylene oxide, propylene oxide, and cyclohexane oxide.

[0019] Use of the polyolefin / aliphatic polycarbonate alloy material of any one of the third aspects in the preparation of packaging materials.

[0020] In some embodiments of the present application, the packaging material includes at least one of a fresh-keeping bag, a fresh-keeping film, a food packaging bag, a food packaging film, a garbage bag, a packaging bottle, a packaging box, and a food tray. DETAILED DESCRIPTION

[0021] Polyolefin materials (PO) usually have good water vapor barrier properties, but poor oxygen barrier properties, so their oxygen barrier properties need to be improved so that they can be used as food packaging materials to extend the shelf life of products. Aliphatic polycarbonate (APC) usually has good oxygen barrier properties, so the preparation of polyolefin / aliphatic polycarbonate alloy materials (referred to as PO / APC alloy materials) is expected to improve the oxygen barrier properties of PO.

[0022] However, PO and APC are thermodynamically incompatible and their chemical structures are quite different, which results in unsatisfactory performance improvement of PO / APC alloy materials. Specifically, the oxygen barrier of PO / APC alloy materials is not significantly improved compared with pure PO. It is usually necessary to add a compatibilizer (polyolefin grafted methacrylate glycerol (PE-g-GMA or PP-g-GMA)) or polyolefin grafted maleic anhydride (PE-g-MAH or PP-g-MAH) to improve the compatibility of such alloys, but the effect of improving the oxygen barrier of PO / APC alloy materials is general.

[0023] The inventors have studied and found that the reason why the above-mentioned compatibilizer does not significantly improve the oxygen barrier effect of PO / APC alloy materials is that APC needs to reach a certain molecular weight to have good oxygen barrier properties, and the higher the molecular weight of APC, the lower the concentration of its terminal hydroxyl groups, which cannot make the compatibilizer (PO-g-GMA or PO-g-MAH) have a good compatibility effect.

[0024] Therefore, the present application provides a method for preparing a compatible modified resin, which is used to prepare a PO / APC alloy material, and can improve the compatibility of polyolefins and aliphatic polycarbonates, thereby making the PO / APC alloy material have better oxygen barrier and mechanical properties.

[0025] The method for preparing the compatible modified resin for the PO / APC alloy material comprises the following steps:

[0026] (1) Plasticizing and mixing aliphatic polycarbonate (APC) and diisocyanate, reacting the terminal hydroxyl group of aliphatic polycarbonate with the NCO terminal group of diisocyanate, grafting terminal isocyanate groups onto aliphatic polycarbonate, and obtaining an isocyanate group-terminated aliphatic polycarbonate intermediate (APC-N=C=O), wherein the concentration of terminal isocyanate groups in the intermediate (APC-N=C=O) is ≥10 mol / t. The intermediate (APC-N=C=O) is used to further prepare a compatible modified resin. Exemplarily, the concentration of terminal isocyanate groups in the intermediate (APC-N=C=O) is 10-20 mol / t; for example, the concentration of terminal isocyanate groups in the intermediate (APC-N=C=O) is 10 mol / t, 15 mol / t or 20 mol / t.

[0027] In some embodiments, the aliphatic polycarbonate (APC) has a terminal hydroxyl concentration of ≥32 mol / t. The higher the terminal hydroxyl concentration of the aliphatic polycarbonate, the easier it is to graft the terminal isocyanate group, so that the subsequent reaction can be used to prepare a compatible modified resin. The terminal isocyanate group refers to the isocyanate group on the terminal group of the new substance formed by the reaction of the terminal hydroxyl group of the aliphatic polycarbonate with the diisocyanate.

[0028] Optionally, the terminal hydroxyl concentration of the aliphatic polycarbonate is 32-60 mol / t. As an example, the terminal hydroxyl concentration of the aliphatic polycarbonate (APC) is 60 mol / t, 55 mol / t, 50 mol / t, 45 mol / t, 40 mol / t or 32 mol / t.

[0029] In some embodiments, the aliphatic polycarbonate (APC) is obtained by polymerization of carbon dioxide and alkylene oxide; optionally, the alkylene oxide includes at least one of ethylene oxide, propylene oxide, and cyclohexane oxide.

[0030] In some embodiments, the diisocyanate includes at least one of toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), dicyclohexylmethane diisocyanate (HMDI), hexamethylene diisocyanate (HDI), and lysine diisocyanate (LDI).

[0031] In some embodiments, the molar ratio of the aliphatic polycarbonate (APC) to the diisocyanate is 100:1-100:3. The molar ratio is selected to react in a suitable range to obtain an intermediate (APC-N=C=O) having a terminal isocyanate group concentration of 10-20 mol / t.

[0032] As an example, the molar ratio of the aliphatic polycarbonate (APC) to the diisocyanate is 100:1, 100:2, or 100:3.

[0033] The following is an explanation using diphenylmethane diisocyanate (MDI) as an example of diisocyanate: aliphatic polycarbonate (APC) and diphenylmethane diisocyanate (MDI) are plasticized and mixed at a molar ratio of 100:1-100:3 (exemplarily, the plasticization and mixing temperature is 130-150°C, the rotation speed is 40-60r / min, and the time is 5-10min) to obtain an intermediate APC-MDI (isocyanate-terminated modified APC) having a terminal isocyanate group concentration of 10-20 mol / t.

[0034] (2) A polyolefin grafted glycidyl methacrylate (PO-g-GMA) with a grafting rate of ≥0.5% is mixed with an intermediate (APC-N=C=O), and the epoxy groups in the polyolefin grafted glycidyl methacrylate react with the terminal isocyanate groups in the intermediate to obtain a compatible modified resin, wherein the concentration of the terminal isocyanate groups in the compatible modified resin is ≤1.5 mol / t, and the residual grafting rate of the compatible modified resin is ≤0.15%. In the reaction, most of the isocyanate groups in APC-N=C=O can react with the epoxy groups in PO-g-GMA, so that the yield of PO-g-APC in the compatible modified resin is higher, which is beneficial to improve the compatibility of the subsequent preparation of polyolefin / aliphatic polycarbonate alloy materials.

[0035] In some embodiments, the polyolefin grafted glycidyl methacrylate (PO-g-GMA) includes at least one of polyethylene grafted glycidyl methacrylate, polypropylene grafted glycidyl methacrylate, and poly-1-butene grafted glycidyl methacrylate.

[0036] In some embodiments, the molar ratio of the polyolefin grafted glycidyl methacrylate (PO-g-GMA) to the intermediate (APC-N=C=O) is 80:20, 75:25, or 70:30. By controlling the molar ratio, more terminal isocyanate groups can react with epoxy groups to connect, thereby making the obtained compatible modified resin have a better improvement effect on the compatibility of the polyolefin / aliphatic polycarbonate alloy material.

[0037] In some embodiments of the present application, PO-g-GMA and APC-MDI with a grafting rate of 0.5%-1% are reacted and blended in a molar ratio of 80:20-70:30 (exemplarily, the reaction blending temperature is 160-190°C, the rotation speed is 100-300r / min, and the time is 1-2min) until the system reaction is balanced to obtain a compatible modified resin.

[0038] Optionally, PO-g-GMA and APC-MDI with a grafting rate of 0.5%-1% are extruded in a molar ratio of 80:20-70:30, with an extrusion temperature of 160-190°C, a rotation speed of 100-300r / min, a residence time of 1-2min, and cooled and pelletized to obtain a compatible modified resin. Although the extrusion temperature, rotation speed and residence time all affect the degree of terminal group reaction of PO-g-GMA and APC-MDI, this application does not need to limit the extrusion temperature, rotation speed and time, etc. As long as the conditions that can make most or even all of the terminal isocyanate groups react with the epoxy groups are within the scope of protection of this application.

[0039] In the present application, the activity of the terminal isocyanate group in the intermediate is relatively high (compared to the activity of the terminal hydroxyl group of the aliphatic polycarbonate), and the amount of the terminal isocyanate group and the grafting rate of PO-g-GMA are relatively appropriate, which can make the collision probability of the terminal isocyanate group and the epoxy group higher, so that the reaction degree of the two is higher, and when the reaction reaches equilibrium, more PO-g-APC can be obtained, and the processing is relatively easy and not easy to agglomerate; in addition, the addition amount of PO-g-GMA and APC-MDI is relatively reasonable, which can avoid the excess of one of the substances, so that the concentration of the terminal isocyanate group in the compatible modified resin is ≤1.5 mol / t, so that when the compatible modified resin is used in the subsequent alloy preparation process, it is avoided to cause further reaction and plasticization problems; the residual grafting rate of the compatible modified resin is ≤0.15%, and more PO-g-APC is formed, so that the compatibility of the polyolefin / aliphatic polycarbonate alloy material can be better improved, so as to subsequently improve the oxygen barrier properties and mechanical strength of the alloy material. When there is an excess of active groups at the MDI end groups in the compatible modified resin, they will extend the chain with the large molecular weight APC during the preparation of the alloy, resulting in an APC molecular weight that is too high and difficult to plasticize and disperse, especially when the end MDI content is high, the dispersion will be worse.

[0040] It should be noted that the PO-g-APC compatible modified resin in the present application is not necessarily a pure substance, that is, the compatible modified resin is not necessarily entirely PO-g-APC, and contains a small amount of other substances (for example, PO-g-GMA or APC-MDI, that is, there is a small amount of raw material residue when the condensation equilibrium is reached, etc., which are all within the scope of protection of the present application).

[0041] The PO-g-APC compatible modified resin prepared by the above method can improve the compatibility of polyolefin and aliphatic polycarbonate, so that the polyolefin / aliphatic polycarbonate alloy material has good oxygen barrier performance, and can also improve the mechanical properties of the alloy material.

[0042] Based on the above-mentioned PO-g-APC compatible modified resin, the present application provides a PO / APC alloy material, which comprises, by weight: 75-95 parts by weight of polyolefin (PO), 5-25 parts by weight of aliphatic polycarbonate (APC) and 2-5 parts by weight of compatible modified resin (PO-g-APC).

[0043] The present application uses the compatible modified resin to improve the compatibility of polyolefin (PO) and aliphatic polycarbonate (APC), so that the obtained polyolefin / aliphatic polycarbonate alloy material has better oxygen barrier properties and mechanical properties.

[0044] In the present application, the APC segment in the compatible modified resin and the APC selected for the alloy matrix can be the same polymerization unit or different polymerization units, and the PO segment in the compatible modified resin and the PO selected for the alloy matrix can be the same polymerization unit or different polymerization units. This application does not make any limitation. As long as it is a polyolefin substance or an aliphatic polycarbonate substance, it is within the protection scope of this application.

[0045] Exemplarily, the main component of the compatible modified resin is PE-g-PPC, and the alloy to be compatibilized is a PE / PPC alloy, that is, the APC segment and PO segment in the compatible modified resin and the APC and PO selected for the alloy matrix are the same polymerization units; alternatively, the main component of the compatible modified resin is PP-g-PEC, and the alloy to be compatibilized is a PE / PPC alloy, that is, the APC segment and PO segment in the compatible modified resin and the APC and PO selected for the alloy matrix are different polymerization units.

[0046] As an example, in the PO / APC alloy material, the weight parts of PO are 75 parts, 80 parts, 85 parts, 90 parts or 95 parts, the weight parts of aliphatic polycarbonate (APC) are 5-25 parts, and the weight parts of compatible modified resin are 2-5 parts.

[0047] In some embodiments, in the PO / APC alloy material, the polyolefin (PO) includes at least one of polyethylene (PE), polypropylene (PP), poly-1-butene (PB-1), and ethylene-butene copolymer.

[0048] In some embodiments, the terminal hydroxyl concentration of the aliphatic polycarbonate (APC) is ≤10 mol / t. The terminal hydroxyl concentration of the aliphatic polycarbonate (APC) is within the above range, which can make the aliphatic polycarbonate (APC) have better oxygen barrier properties and be easy to process and disperse in polyolefin (PO), so as to obtain a polyolefin / aliphatic polycarbonate alloy material with better oxygen barrier effect.

[0049] As an example, in the PO / APC alloy material, the terminal hydroxyl concentration of the aliphatic polycarbonate (APC) is 5 mol / t, 7 mol / t, 8 mol / t, 9 mol / t or 10 mol / t. Further, the terminal hydroxyl concentration of the aliphatic polycarbonate (APC) is 5-10 mol / t.

[0050] In some embodiments, in the PO / APC alloy material, the aliphatic polycarbonate (APC) is obtained by polymerization of carbon dioxide and alkylene oxide; optionally, the alkylene oxide includes at least one of ethylene oxide, propylene oxide, and cyclohexane oxide.

[0051] In the present application, the polyolefin / aliphatic polycarbonate alloy material can be physically blended by conventional screw blending and extrusion. The physical blending process can be a conventional blending process of polyolefin / aliphatic polycarbonate alloy material. The exemplary blending and extrusion temperature is 150℃-180℃, the rotation speed is 100-300r / min, and after cooling and pelletizing, a polyolefin / aliphatic polycarbonate alloy material with high oxygen resistance is obtained. Before screw extrusion, it can be measured and mixed offline or measured online. The so-called offline metering and mixing means that all materials are weighed first and then stirred and mixed evenly with a high-speed mixer. The mixed materials are directly put into the material bin of the extruder. When offline metering and mixing are used, the mixing temperature should not be higher than 50℃ to reduce the possibility of material adhesion. The so-called online metering means that all materials enter the material bin of the extruder according to a certain metering ratio, and instantaneous mixing is achieved in the material bin. The above is only an exemplary method, and metering and mixing by any other method is possible.

[0052] Exemplarily, according to processing requirements, the polyolefin / aliphatic polycarbonate alloy material may also contain one or more lubricants, opening agents, and antioxidants. The lubricants commonly include polyethylene wax, oxidized polyethylene wax, paraffin, palm wax, Fischer-Tropsch wax, montan wax, rice bran wax, ethylene bisstearamide, stearic acid, calcium stearate or magnesium stearate, and the addition amount is usually 0.1-1 parts by weight; the opening agent is oleamide, erucamide, talcum powder, silicon dioxide, diatomaceous earth or calcium carbonate, and the addition amount is usually 0.1-1 parts by weight; the antioxidant is antioxidant 1010, antioxidant 1076, antioxidant 168 or DLTP, and the addition amount is usually 0.1-1 parts by weight.

[0053] The above-mentioned polyolefin / aliphatic polycarbonate alloy material can be used to prepare packaging materials; optionally, the packaging material includes at least one of a fresh-keeping bag, a fresh-keeping film, a food packaging bag, a food packaging film, a garbage bag, a packaging bottle, a packaging box, and a food tray.

[0054] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below. In the embodiments, if the manufacturer of the reagents or instruments used is not indicated, conventional products purchased commercially or prepared by themselves can be selected according to the specification characteristics. If the specific conditions are not indicated, the conventional conditions or the conditions recommended by the manufacturer shall be followed.

[0055] Example raw materials list:

[0056] PO: LLDPE, MI 2.0 (190℃*2.16kg, MFR);

[0057] APC-1: polypropylene carbonate, terminal hydroxyl concentration is 8 mol / t;

[0058] APC-2: polypropylene carbonate, terminal hydroxyl concentration is 7 mol / t;

[0059] APC-3: polypropylene carbonate, terminal hydroxyl concentration is 10 mol / t;

[0060] APC-4: polypropylene carbonate, terminal hydroxyl concentration is 32 mol / t;

[0061] APC-5: polypropylene carbonate, terminal hydroxyl concentration is 60 mol / t;

[0062] APC-6: polypropylene carbonate, terminal hydroxyl concentration is 46 mol / t;

[0063] PE-g-GMA-1: polyethylene grafted with glycidyl methacrylate, with a grafting rate of 0.5%;

[0064] PE-g-GMA-2: polyethylene grafted with glycidyl methacrylate, with a grafting rate of 1%;

[0065] PE-g-GMA-3: polyethylene grafted with glycidyl methacrylate, with a grafting rate of 0.8%;

[0066] Example 1

[0067] Preparation of compatible modified resin:

[0068] (1) APC and diisocyanate are plasticized and mixed at a molar ratio of 100:1 (the plasticizing and mixing temperature is 130° C., the rotation speed is 40 r / min, and the time is 5 min). The APC is APC-4 and the diisocyanate is MDI. At this time, the terminal hydroxyl groups of APC react to reach equilibrium to obtain an intermediate APC-MDI. The isocyanate concentration of the intermediate is 10 mol / t.

[0069] (2) PE-g-GMA-2 and the intermediate obtained in step (1) are selected for reaction extrusion in a mass ratio of 70:30, wherein the extrusion is carried out at a temperature of 160° C., a rotation speed of 100 r / min, and a residence time of 2 min. At this time, the isocyanate concentration is 1.1 mol / t, and the residual grafting rate is 0.15%. Then, the mixture is cooled and pelletized to obtain a compatible modified resin.

[0070] Preparation of PO / APC alloy material:

[0071] 95 kg of PO, 5 kg of APC-1 and 2 kg of the compatible modified resin obtained in step (2) were blended and extruded at a temperature of 160° C. and a rotation speed of 200 r / min. After cooling and pelletizing, a PE / APC alloy material was obtained.

[0072] Example 2

[0073] Preparation of compatible modified resin:

[0074] (1) APC and diisocyanate are plasticized and mixed at a molar ratio of 100:2 (the plasticization mixing temperature is 140° C., the rotation speed is 50 r / min, and the time is 8 min). The APC is APC-5 and the diisocyanate is IPDI. At this time, the terminal hydroxyl groups of APC react to reach equilibrium to obtain an intermediate APC-IPDI. The isocyanate concentration of the intermediate is 20 mol / t.

[0075] (2) PE-g-GMA-3 and the intermediate obtained in step (1) are selected for reaction extrusion in a mass ratio of 80:20, wherein the extrusion is carried out at a temperature of 170° C., a rotation speed of 180 r / min, and a residence time of 1.5 min. At this time, the isocyanate concentration is 1.4 mol / t, and the residual grafting rate is 0.1%. Then, the mixture is cooled and pelletized to obtain a compatible modified resin.

[0076] Preparation of PO / APC alloy material:

[0077] 85 kg of PO, 15 kg of APC-2 and 4 kg of the compatible modified resin obtained in step (2) were blended and extruded at a temperature of 160° C. and a rotation speed of 200 r / min. After cooling and pelletizing, a PE / APC alloy material was obtained.

[0078] Example 3

[0079] Preparation of compatible modified resin:

[0080] (1) APC and diisocyanate were plasticized and mixed at a molar ratio of 100:3 (the plasticization mixing temperature was 150° C., the rotation speed was 60 r / min, and the time was 10 min). The APC was APC-6 and the diisocyanate was HDI. At this time, the terminal hydroxyl groups of APC reacted to reach equilibrium to obtain an intermediate APC-HDI. The isocyanate concentration of the intermediate was 15 mol / t.

[0081] (2) PE-g-GMA-1 and the intermediate obtained in step (1) are selected for reaction extrusion, with a mass ratio of 75:25, wherein the extrusion is carried out at a temperature of 190° C., a rotation speed of 300 r / min, and a residence time of 1 min. At this time, the isocyanate concentration is 1.5 mol / t, and the residual grafting rate is 0.09%. Then, the mixture is cooled and pelletized to obtain a compatible modified resin.

[0082] Preparation of PO / APC alloy material:

[0083] 75 kg of PO, 25 kg of APC-3 and 5 kg of the compatible modified resin obtained in step (2) were blended and extruded at a temperature of 160° C. and a rotation speed of 200 r / min. After cooling and pelletizing, a PO / APC alloy material was obtained.

[0084] Comparative Example 1

[0085] The difference between Comparative Example 1 and Example 1 is that when preparing the PE / APC alloy material, no compatible modified resin is added, but 2 kg of PE-g-GMA-1 is added.

[0086] Comparative Example 2

[0087] The difference between Comparative Example 2 and Example 1 is:

[0088] Preparation of compatible modified resin:

[0089] (1) The molar ratio of APC to diisocyanate was adjusted to 100:0.9, and the rest remained unchanged to obtain an intermediate APC-MDI, wherein the isocyanate concentration of the intermediate was 8 mol / t.

[0090] (2) PE-g-GMA-2 and the intermediate obtained in step (1) are selected for reaction extrusion. Under the same conditions, the intermediate has an isocyanate concentration of 0.9 mol / t and a residual grafting rate of 0.23%. The intermediate is then cooled and pelletized to obtain a compatible modified resin.

[0091] Comparative Example 3

[0092] The difference between Comparative Example 3 and Example 1 is that:

[0093] The extrusion temperature of step (2) is 145° C., and the other processes remain unchanged. At this time, the isocyanate concentration is 1.6 mol / t, and the residual grafting rate is 0.39%. Then, the mixture is cooled and pelletized to obtain a compatible modified resin PE-g-APC.

[0094] Experimental example

[0095] The terminal hydroxyl concentration of APC, the isocyanate concentration of the intermediate, the GMA grafting rate of PE-g-GMA, the isocyanate concentration and the GMA residual grafting rate of the compatible modified resin (PE-g-APC), and the tensile strength, elongation at break and oxygen permeability of the PO / APC alloy material provided in the above examples and comparative examples were tested, and the results are shown in Table 1. The testing method is as follows:

[0096] (1) End hydroxyl concentration: The APC raw material was fully dried, and then the end hydroxyl concentration of the APC raw material was tested by nuclear magnetic resonance using deuterated chloroform as solvent.

[0097] (2) Terminal isocyanate group concentration: The intermediate and the compatible modified resin were fully dried, and then the terminal isocyanate concentration of the intermediate and the compatible modified resin was tested by nuclear magnetic resonance using deuterated chloroform as solvent.

[0098] (3) Determination of PE-g-GMA grafting rate and GMA residual grafting rate of compatible modified resin: Accurately weigh 0.5g of sample, put it into a conical flask, add 80mL of xylene, heat and reflux until the grafted material is completely dissolved, then add 50mL of KOH / ethanol solution, heat and reflux for 4h, and perform chemical titration with a known concentration of HCl / isopropanol standard solution. The product grafting rate (G) is calculated according to the following formula:

[0099]

[0100] Where: V1 is the volume of HCl consumed in the blank experiment, mL; V2 is the volume of HCl consumed in the grafted sample, mL; C is the molar concentration of HCl / isopropanol solution, mol / L; m is the mass of the grafted material, g.

[0101] (4) Tensile strength and elongation at break: The pelletized PO / APC alloy material was cast at 190°C to obtain an alloy film with a thickness of 1 mm. The tensile strength and elongation at break were tested on a universal testing machine according to the test methods provided in GB / T 1040.1-2018 "Test for tensile properties of plastics Part 1: General" and GB / T 1040.2-2006 "Test for tensile properties of plastics Part 2: Test conditions for molded and extruded plastics". The tensile speed was 500 mm / min.

[0102] (5) Oxygen permeability: The P0 / APC alloy material is cast at 190°C to form an alloy material film with a thickness of 0.1 mm. The gas permeability is measured using a gas permeability meter in accordance with the test method of standard GB / T 1038.1-2022 "Test method for gas permeability of plastic film and sheeting - Part 1: Differential pressure method". The test method adopts Appendix A: Pressure sensor method. The gas permeability is measured under high-purity oxygen (purity ≥99.999%) gas conditions, which is the oxygen permeability.

[0103] Table 1 Properties of PO / APC alloy materials

[0104]

[0105] By comparing Examples 1-3 with Comparative Example 1, it can be seen that compared with PE-g-GMA-1, the compatible modified resin provided in the present application can improve the compatibility of the PO / APC alloy material, improve the oxygen barrier performance of the PE / APC alloy material, and at the same time, the elongation at break is also improved.

[0106] By comparing Examples 1-3 with Comparative Example 2, it can be seen that in Comparative Example 2, the isocyanate concentration in the intermediate is too low, resulting in an excessively high residual grafting rate of GMA in the obtained compatible modified resin, indicating that the effective collision probability between the isocyanate group of the intermediate and the GMA group in PE-g-GMA is low, the degree of reaction is low, and the yield of PE-g-APC in the obtained compatible modified resin is low, which will affect the oxygen barrier properties of the PO / APC alloy material.

[0107] By comparing Examples 1-3 with Comparative Example 3, it can be seen that in Comparative Example 3, due to the low reaction temperature, the reaction is not sufficient under this condition, and the isocyanate concentration in the compatible modified resin is too high. When preparing the PO / APC alloy material, it will extend the chain with the large molecular weight APC in the alloy material, resulting in the APC molecular weight being too high, making it difficult to plasticize and disperse, which will affect the oxygen barrier properties of the PO / APC alloy material.

[0108] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

Claims

1. A method for preparing a compatible modified resin for polyolefin / aliphatic polycarbonate composite, wherein the compatible modified resin is used for the compatible modification of a polyolefin / aliphatic polycarbonate alloy system, characterized in that: include: Plasticizing and mixing aliphatic polycarbonate and diisocyanate to graft terminal isocyanate groups onto the aliphatic polycarbonate to obtain an isocyanate group-terminated aliphatic polycarbonate intermediate, wherein the concentration of the isocyanate groups in the intermediate is ≥10 mol / t; The polyolefin grafted glycidyl methacrylate with a grafting rate of ≥0.5% is mixed with the intermediate, and the epoxy group in the polyolefin grafted glycidyl methacrylate reacts with the terminal isocyanate group in the intermediate to obtain the compatible modified resin, wherein the concentration of the terminal isocyanate group in the compatible modified resin is ≤1.5 mol / t, and the residual grafting rate of the compatible modified resin is ≤0.15%.

2. The method for preparing a compatible modified resin according to claim 1, characterized in that: The terminal hydroxyl concentration of the aliphatic polycarbonate is ≥32 mol / t; optionally, the terminal hydroxyl concentration of the aliphatic polycarbonate is 32-60 mol / t.

3. The method for preparing the compatible modified resin according to claim 1, characterized in that: The diisocyanate includes at least one of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, and lysine diisocyanate.

4. The method for preparing a compatible modified resin according to claim 1, characterized in that: The molar ratio of the aliphatic polycarbonate to the diisocyanate is 100:1-100:3; Or / and, the concentration of the isocyanate groups in the intermediate is 10-20 mol / t; Or / and, the grafting rate of polyolefin grafted glycidyl methacrylate is 0.5-1%.

5. The method for preparing a compatible modified resin according to any one of claims 1 to 4, characterized in that: The polyolefin grafted glycidyl methacrylate includes at least one of polyethylene grafted glycidyl methacrylate, polypropylene grafted glycidyl methacrylate, and poly-1-butene grafted glycidyl methacrylate.

6. A compatible modified resin, characterized in that: The compatibility-modified resin is prepared by the preparation method according to any one of claims 1 to 5, and is used to compound polyolefin and aliphatic polycarbonate.

7. A polyolefin / aliphatic polycarbonate alloy material, characterized in that: In parts by weight, it comprises: 100 parts of alloy resin base material and 2-5 parts by weight of the compatible modified resin according to claim 6; the alloy resin base material comprises 75-95 parts by weight of polyolefin and 5-25 parts by weight of aliphatic polycarbonate.

8. The polyolefin / aliphatic polycarbonate alloy material according to claim 7, characterized in that: The polyolefin includes at least one of polyethylene, polypropylene, poly-1-butene, and ethylene and butene copolymers.

9. The polyolefin / aliphatic polycarbonate alloy material according to claim 7, characterized in that: The terminal hydroxyl concentration of the aliphatic polycarbonate is ≤10 mol / t; Or / and, the aliphatic polycarbonate is obtained by polymerization of carbon dioxide and alkylene oxide; optionally, the alkylene oxide includes at least one of ethylene oxide, propylene oxide and cyclohexane oxide.

10. Use of the polyolefin / aliphatic polycarbonate alloy material according to any one of claims 7 to 9 in preparing packaging materials; Optionally, the packaging material includes a fresh-keeping bag, a fresh-keeping film, a food packaging bag, a food packaging film, a garbage bag, a packaging bottle, a packaging box or a food tray.

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