Method for preparing special master batch for polypropylene hollow plate by utilizing dolomite compound modification

Abstract

The invention discloses a method for preparing a special master batch for a polypropylene hollow plate by utilizing compound modification of dolomite. The special master batch is prepared from the following components in parts by weight: 8-58 parts of dolomite, 8-58 parts of calcium carbonate, 30-60 parts of polypropylene, 0.2-1.0 part of a coupling agent and 0.2-1.0 part of a lubricant. Wherein the polypropylene is co-polypropylene and homo-polypropylene. According to the method provided by the invention, after blending, the production cost of the polypropylene hollow plate is reduced, the elongation at break of the polypropylene hollow plate is improved, and the ageing resistance is also improved.

Description

Technical Field

[0001] The invention relates to the technical field of polymer material processing and the field of polypropylene hollow board preparation, and in particular to a method for preparing a special masterbatch for polypropylene hollow boards by using dolomite composite modification. Background Art

[0002] This section merely provides background information related to the present disclosure and is not necessarily prior art.

[0003] Polypropylene (PP) is the most widely used polyolefin and one of the commodity plastics with the highest growth rate. PP has good chemical resistance, heat resistance and fatigue resistance, semi-rigid, semi-transparent, tough and integral hinge properties. However, the application range of PP in engineering thermoplastics is severely limited by its high flammability, low temperature brittleness and low stiffness at low temperatures. In addition, PP is non-polar in nature, so it is not very compatible with almost all polar fillers and reinforcements used in the polymer industry.

[0004] One of the main key challenges in producing inorganic / organic composite materials with excellent performance is to overcome the agglomeration of mineral filler particles in the polypropylene matrix. The preparation steps of traditional polypropylene hollow boards include the preparation of filling masterbatch, drawing the board after mixing the filling masterbatch with polypropylene resin, and cutting the board. At present, the inorganic fillers in the filling masterbatch are mostly unmodified calcium carbonate powder, which significantly reduces the toughness of the hollow board. Compared with calcium carbonate, dolomite has good toughness and thermal stability, but the latter is not as stiff as the former. However, only filling dolomite or calcium carbonate powder cannot be well combined with polypropylene. The performance of polypropylene hollow boards prepared with single mineral powder as filler is weak and is no longer suitable for the current rapidly developing logistics packaging industry. Polypropylene hollow boards with good anti-aging performance and long cycle life will be more popular in the market. In addition, the production process of preparing the filling masterbatch first and then mixing the filling masterbatch with the resin to prepare the hollow board is cumbersome, and too many production processes will generate more energy consumption and waste emissions, aggravating environmental damage. Therefore, the present invention proposes a preparation method of a special masterbatch containing composite modified powder, which directly produces hollow boards through the special masterbatch, reduces production steps and reduces dual-carbon energy consumption, enhances environmental protection and improves industrial efficiency. Summary of the invention

[0005] Purpose of the invention: The technical problem to be solved by the present invention is to provide a polypropylene hollow board or a special masterbatch for preparing a polypropylene hollow board, and a preparation method of the aforementioned hollow board and special masterbatch in view of the shortcomings of the prior art.

[0006] In order to solve the above technical problems, the present invention discloses the following technical solutions:

[0007] In a first aspect, the present invention discloses a polypropylene hollow board and a special masterbatch for preparing the polypropylene hollow board.

[0008] The polypropylene hollow board and the special masterbatch for preparing the polypropylene hollow board are made of the following components in parts by weight:

[0009] Dolomite 8-58 parts

[0010] Calcium carbonate 8-58 parts

[0011] Polypropylene 30-60 parts

[0012] Coupling agent 0.2-1.0 parts

[0013] Lubricant 0.2-1.0 parts

[0014] Wherein, the polypropylene is a combination of copolymer polypropylene and homopolymer polypropylene.

[0015] In a second aspect, the present invention discloses a polypropylene hollow board and a method for preparing a special masterbatch for preparing the polypropylene hollow board.

[0016] The polypropylene hollow board and the special masterbatch for preparing the polypropylene hollow board are made of the following components in parts by weight:

[0017] Dolomite 8-58 parts

[0018] Calcium carbonate 8-58 parts

[0019] Polypropylene 30-60 parts

[0020] Coupling agent 0.2-1.0 parts

[0021] Lubricant 0.2-1.0 parts

[0022] Wherein, the polypropylene is a combination of copolymer polypropylene and homopolymer polypropylene.

[0023] In the above first and second aspects,

[0024] The molecular weight of the copolymer polypropylene described in the present invention is 50,000 to 500,000, such as 80,000 to 150,000, and the melt index is 1.8-2.7 g / 10 min, such as 2-2.5 g / 10 min; such as the copolymer polypropylene of Sinopec (model: K8003, molecular weight: 50,000 to 500,000, melt index: 2.5 g / 10 min) and the copolymer polypropylene of Maoming Branch of Sinopec (model: M02D, molecular weight: 80,000 to 150,000, melt index: 1.8 g / 10 min).

[0025] The molecular weight of the homopolymer polypropylene described in the present invention is 80,000 to 150,000, and the melt index is 0.5-4g / 10min, such as 3.0g / 10min; such as the homopolymer polypropylene of the State Energy Group (model: 1102K, molecular weight: 80,000 to 150,000, melt index: 3.0g / 10min), and the homopolymer polypropylene of the Taiwan Plastics Industry Co., Ltd. (model: 1005N, molecular weight: 80,000 to 150,000, melt index: 0.5g / 10min).

[0026] In some embodiments, the weight proportions of the components are as follows:

[0027] Dolomite 10-53 parts

[0028] Calcium carbonate 10-53 parts

[0029] Polypropylene 35-50 parts

[0030] Coupling agent 0.4-0.8 parts

[0031] Lubricant 0.4-0.8 parts.

[0032] In some embodiments, the weight proportions of the components are as follows:

[0033] Dolomite 12-48 parts

[0034] Calcium carbonate 12-48 parts

[0035] Polypropylene 40 parts

[0036] Coupling agent 0.6 parts

[0037] 0.6 parts of lubricant.

[0038] In some embodiments, the mass ratio of copolymerized polypropylene to homopolymerized polypropylene is 0.1-5.2:1, in some embodiments, 0.2-4.7:1, and in some embodiments, 7:33, 13:27, 20:20, 27:13, or 33:7.

[0039] In some embodiments, the dolomite and calcium carbonate are fine powders exceeding 800-1500 mesh, such as exceeding 1250 mesh, and the dolomite and calcium carbonate can be crushed by air flow milling.

[0040] In some embodiments, the coupling agent is an aluminate coupling agent and / or a titanate coupling agent; in some embodiments, the aluminate coupling agent is aluminate coupling agent DL-411, and the titanate coupling agent is titanate coupling agent NDZ-201.

[0041] In some embodiments, the lubricant is stearic acid and / or zinc stearate.

[0042] In some embodiments, the preparation method comprises the following steps:

[0043] (1) premixing dolomite and calcium carbonate, adding a coupling agent, a lubricant, and polypropylene to mix, and obtaining a mixture;

[0044] (2) plasticizing the obtained mixture in an internal mixer to obtain a mixture melt;

[0045] (3) the obtained mixed material melt is plasticized and granulated in a twin-screw extruder to obtain a masterbatch for polypropylene hollow board;

[0046] (4) The polypropylene hollow board masterbatch is pressed into a plate by a hot press and placed in a cool place to obtain a polypropylene hollow board with excellent anti-aging performance prepared from a dolomite composite modified powder raw material; or the polypropylene hollow board masterbatch is sent to a hollow board drawing machine to obtain a polypropylene hollow board with excellent anti-aging performance prepared from a dolomite composite modified powder raw material.

[0047] In step (1), dolomite and calcium carbonate are put into a high-speed mixer, the speed is adjusted to 600-800 r / min, and premixed at 115-135° C. for 10-20 min. A coupling agent is first added and premixed for 2-10 min, a lubricant is added and premixed for 2-8 min, and polypropylene is added and mixed for 4-12 min to obtain a mixture.

[0048] In step (2), the plasticizing temperature is 180-220° C., preferably 190-210° C.; in some embodiments, the plasticizing is performed at a rotation speed of 400-600 r / min.

[0049] In step (3), the temperature range of the twin-screw extruder is 180-190°C, 185-195°C, 190-200°C, 195-205°C, 200-210°C, 205-215°C, 210-220°C, 210-220°C, 205-215°C, preferably 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, 210°C; in some embodiments, the speed of the twin-screw extruder is 150-170rpm, the melt flow rate is 50-60L / min, and the air-cooled hot cut is 4-6Hz.

[0050] Modifying calcium carbonate dolomite powder alone is difficult to bring out their characteristic advantages. The present invention is aimed at dolomite and calcium carbonate composite modified powder, combined with the characteristics and properties of dolomite material with good heat resistance and high toughness, and proposes a method for preparing polypropylene hollow board with dolomite modified raw materials. Based on the structure, morphology and ultra-fineness, different pretreatments are performed to make special materials, replacing the conventional method of preparing filling masterbatch with untreated calcium carbonate powder and then adding polypropylene to prepare polypropylene hollow board.

[0051] The method provided by the present invention improves the problem of poor aging resistance of traditional polypropylene hollow boards, reduces the operation process during processing, and at the same time increases the added value of dolomite, thereby reducing the production cost of polypropylene hollow boards. When only a small amount of polypropylene is used as a composite material modified filler load with dolomite and calcium carbonate, the results show that the composite modification of dolomite, polypropylene and calcium carbonate successfully achieves a synergistic hybrid effect. The mechanical properties show higher tensile strength and elongation at break, while significantly improving the toughness and anti-aging performance of the polypropylene hollow board, achieving the effect of toughening and strengthening, thereby realizing the long-term use of the polypropylene hollow board.

[0052] The outstanding advantages of the present invention are: ① According to the properties and characteristics of dolomite, dolomite is partially substituted for the inorganic filler of calcium carbonate, and after mixed modification, a composite modified inorganic powder raw material is obtained to prepare a polypropylene hollow board that can be used for building materials. The preparation of special materials effectively reduces the processing steps, improves production efficiency, and reduces the manufacturing cost of polypropylene hollow boards. ② Under low filler, the dispersibility of the modified dolomite particles is better. On the one hand, the ultrafine dolomite powder as a solid solution can make the modified composite powder tougher and stronger; on the other hand, dolomite and calcium carbonate have similar structures and components. After blending, due to the principle of similar dissolution, the binding force between the molecules of the two is still very strong, which is reflected in the macroscopic view that the composite powder still maintains excellent mechanical properties. ③ Formula optimization, when dolomite and calcium carbonate powder are mixed and composite modified, the anti-aging performance of the obtained polypropylene hollow board is significantly improved. Elongation at break is one of the important indicators for measuring the ductility or toughness of materials. The polypropylene hollow board prepared by the composite modified powder containing dolomite has a better elongation at break than the traditional single calcium carbonate powder to prepare the polypropylene hollow board. Only a small amount of dolomite and calcium carbonate were used as modified fillers in the composite material. The results showed that the dolomite composite modified powder successfully achieved a synergistic hybrid effect.

[0053] Beneficial effects:

[0054] The invention makes full use of the advantages of good heat resistance and high toughness of dolomite, replaces part of calcium carbonate and mixes and composites with calcium carbonate to prepare polypropylene hollow plates, thereby reducing the preparation cost and effectively improving the service life and added value of the polypropylene hollow plates.

[0055] After blending, the method provided by the present invention reduces the production cost of the polypropylene hollow board and increases its elongation at break, and also improves its anti-aging property.

[0056] The method provided by the present invention prepares hollow plates in the form of dolomite modified powder polypropylene special material production, improves the current domestic method of first preparing filling masterbatch and then adding polypropylene, and reduces production steps. DETAILED DESCRIPTION

[0057] The present invention can be better understood according to the following examples. However, it is easy for those skilled in the art to understand that the contents described in the examples are only used to illustrate the present invention, and should not and will not limit the present invention described in detail in the claims.

[0058] The experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0059] The raw material manufacturers of copolymer polypropylene (model: K8003 and M02D) described in the following examples are China Petrochemical Corporation, the raw material manufacturers of homopolypropylene (model: 1102K; model: 1005N) are State Energy Group and Taiwan Plastics Industry Co., Ltd., and the raw material manufacturers of stearic acid (model: 1840), zinc stearate (CAS No.: 557-05-1) and coupling agent (model: DL-411) are Dongguan Dinghai Plastic Chemical Co., Ltd.

[0060] In the following examples, the mechanical properties are measured with reference to the national standard test strips. The tensile and bending properties of the composite material strips are tested by an electronic universal mechanical testing machine, and the impact properties are tested by a cantilever beam impact testing machine.

[0061] Tensile property test: According to GB / T 1040.2-2006 standard, the test piece is a dumbbell-shaped test piece of 170mm×20mm×4mm, the narrow width is 10mm, and the preferred thickness is 4mm. The measuring gauge length is 50mm, and the test speed is 50mm / min.

[0062] Bending performance test: According to GB / T 9341-2008 standard, the specimen size is 80mm×10mm×4mm, the test span is 64mm, and the test speed is 2mm / min.

[0063] Impact performance test: According to GB / T 1843-2008 standard, notch impact mode is adopted, the specimen size is 80mm×10mm×4mm, the impact energy is 5.5J, and the impact speed is 2.9m / s.

[0064] Aging performance test: According to GB / T 16422.3-2022 standard, the specimen size is 80mm×10mm×4mm, and a UVA-351 (1B type) test chamber is used, with a uniform irradiance of 0.76W / (m 2 ·nm), aged at 50℃ for 28 days.

[0065] The parts described in the following examples are all parts by weight unless otherwise specified.

[0066] Example 1 Preparation of polypropylene hollow board using composite modified raw material containing dolomite

[0067] (1) First, dolomite and calcium carbonate were ground into ultrafine powder of 1250 mesh by air jet mill, and 48 parts of calcium carbonate of 1250 mesh ultrafine powder and 12 parts of dolomite of 1250 mesh ultrafine powder were put into high-speed mixer, and the speed was adjusted to 700r / min for high-speed premixing, and pretreated for 15 minutes at a constant temperature of 125°C. Then, 0.6 parts of aluminate coupling agent (model DL-411) were added and premixed for 5 minutes, and then 0.3 parts of stearic acid and 0.3 parts of zinc stearate were added and premixed for 5 minutes. Subsequently, 7 parts of copolymerized polypropylene (K8003) and 33 parts of homopolymerized polypropylene (1102K) were added and mixed for 8 minutes to obtain a uniform mixture.

[0068] (2) The obtained mixture is transferred to a low-speed mixer and then fed into a continuous internal mixer at a feeding speed of 8 r / min. It is plasticized at a melting temperature of 200° C. and a rotation speed of 500 r / min to obtain a mixture melt.

[0069] (3) The obtained mixed material melt enters a twin-screw extruder through a forced feeder for plasticization and granulation again. The extrusion conditions are [temperature range: 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, 215°C, 210°C; extrusion speed 160rpm, melt flow rate 55L / min, air cooling and hot cutting 5.0Hz] to obtain a masterbatch for hollow plates. After drying, it can be injection molded into standard specimens for testing.

[0070] Example 2

[0071] Same as Example 1, except that copolymer polypropylene (K8003) and homopolypropylene (1102K) are replaced by copolymer polypropylene (M02D) and homopolypropylene (1005N).

[0072] Comparative Example

[0073] Same as Example 1, except that the amounts of the components in step (1) are different, as follows:

[0074] Table 1

[0075]

[0076] The polypropylene hollow board made by the above method was tested, and the results are as follows:

[0077] Table 2

[0078]

[0079] The polypropylene hollow board made by the above method was tested after aging, and the results are as follows:

[0080] Aging conditions: 50℃ UV aging for 28 days.

[0081] Table 3

[0082]

[0083] It can be seen that the present invention uses dolomite as a reinforcing aggregate by compositely modifying two inorganic mineral powders with similar components to improve the bonding performance between polypropylene and filler to a certain extent, and can further improve the aging resistance of the polypropylene hollow board.

[0084] Example 3

[0085] The same as Example 1, except that the amount of copolymerized polypropylene and homopolymerized polypropylene was changed, and the results were as follows:

[0086] Table 4

[0087]

[0088] Example 4

[0089] Same as Example 1, except that the amount of calcium carbonate and dolomite was changed and the results were as follows:

[0090] Table 5

[0091]

[0092] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing a polypropylene hollow board or a masterbatch for polypropylene hollow board, characterized in that: Made from the following components in parts by weight: Dolomite 8-58 parts Calcium carbonate 8-58 parts Polypropylene 30-60 parts Coupling agent 0.2-1.0 parts Lubricant 0.2-1.0 parts Wherein, the polypropylene is a combination of copolymer polypropylene and homopolymer polypropylene.

2. The preparation method according to claim 1, characterized in that: The weight parts of each component are as follows: Dolomite 10-53 parts Calcium carbonate 10-53 parts Polypropylene 35-50 parts Coupling agent 0.4-0.8 parts Lubricant 0.4-0.8 parts.

3. The preparation method according to claim 1, characterized in that: The weight parts of each component are as follows: Dolomite 12-48 parts Calcium carbonate 12-48 parts Polypropylene 40 parts Coupling agent 0.6 parts 0.6 parts of lubricant.

4. The preparation method according to any one of claims 1 to 3, characterized in that: The mass ratio of copolymerized polypropylene to homopolymerized polypropylene is 0.1-5.2:1, preferably 0.2-4.7:1, preferably 7:33, 13:27, 20:20, 27:13 or 33:

7.

5. The preparation method according to any one of claims 1 to 3, characterized in that: The dolomite and calcium carbonate are fine powders with a mesh size of 800-1500.

6. The preparation method according to any one of claims 1 to 3, characterized in that: The coupling agent is an aluminate coupling agent and / or a titanate coupling agent; the lubricant is stearic acid and / or zinc stearate.

7. The preparation method according to any one of claims 1 to 3, characterized in that: The following steps are involved: (1) premixing dolomite and calcium carbonate, adding a coupling agent, a lubricant, and polypropylene to mix, and obtaining a mixture; (2) plasticizing the obtained mixture in an internal mixer to obtain a mixture melt; (3) The obtained mixed material melt is plasticized and granulated in a twin-screw extruder to obtain a masterbatch for polypropylene hollow board.

8. The preparation method according to claim 7, characterized in that: In step (1), dolomite and calcium carbonate are premixed for 10-20 minutes, a coupling agent is first added and premixed for 2-8 minutes, a lubricant is then added and premixed for 2-8 minutes, and polypropylene is then added and mixed for 4-12 minutes to obtain a mixture.

9. The preparation method according to claim 7, characterized in that: In step (2), the plasticizing temperature is 180-220°C, preferably 190-210°C; in step (3), the temperature interval of the twin-screw extruder is 180-190°C, 185-195°C, 190-200°C, 195-205°C, 200-210°C, 205-215°C, 210-220°C, 210-220°C, 205-215°C, preferably 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, 210°C.

10. The polypropylene hollow board professional masterbatch or polypropylene hollow board prepared by the method according to any one of claims 1 to 9.

Images