A polyolefin material, its preparation method and application

Abstract

This invention belongs to the field of polymer materials technology, specifically relating to a polyolefin material, its preparation method, and its applications. The polyolefin material is characterized by comprising the following components in parts by weight: 50-70 parts polyolefin resin, 15-24 parts brominated flame retardant, 4-10 parts antimony trioxide, 1-5 parts melamine cyanurate, 3-15 parts ammonium polyphosphate, 1-5 parts piperazine pyrophosphate, and 0.2-2 parts laser marking agent. The polyolefin material obtained by this invention exhibits excellent laser marking performance and flame retardant properties.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to a polyolefin material, its preparation method, and its application. Background Technology

[0002] Laser marking is a common marking method for molded plastic parts, offering advantages such as high efficiency, environmental friendliness, and economy. Polyolefins are currently the most widely used type of general-purpose plastics, making the laser marking performance of polypropylene particularly crucial. Generally, there are two mechanisms for laser marking of polyolefins: high-temperature carbonization and expansion foaming. Both achieve the marking purpose by destroying the surface material through different laser energies.

[0003] The laser marking performance of flame-retardant polyolefins has always been a pain point in the industry. Generally, adding a laser absorber (also known as a laser marking agent) can effectively improve the laser marking performance of polypropylene. However, in brominated flame-retardant polypropylene, due to the influence of the flame retardant, the laser energy absorbed by the laser absorber will preferentially promote the decomposition of the flame retardant. The heat generated is difficult to directly promote the carbonization or foaming and color development of the resin, which greatly reduces the effect of laser marking. Moreover, the casings of electronic components are generally small in size, and their requirements for laser marking efficiency and clarity are very high. Currently, the laser marking performance of flame-retardant polypropylene cannot meet the application requirements.

[0004] Therefore, there is an urgent need to develop a flame-retardant polypropylene material with high-efficiency laser marking performance. Summary of the Invention

[0005] This invention aims to provide a polyolefin material, its preparation method, and its applications. The polyolefin material obtained by this invention exhibits excellent laser marking performance and flame retardant properties.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a polyolefin material comprising the following components by weight: 50-70 parts of polyolefin resin, 15-24 parts of brominated flame retardant, 4-10 parts of antimony trioxide, 1-5 parts of melamine cyanurate, 3-15 parts of ammonium polyphosphate, 1-5 parts of piperazine pyrophosphate, and 0.2-2 parts of laser marking agent.

[0007] Preferably, the polyolefin material comprises the following components in parts by weight: 60-65 parts polyolefin resin, 18-20 parts brominated flame retardant, 7-8 parts antimony trioxide, 3-4 parts melamine cyanurate, 8-10 parts ammonium polyphosphate, 2-3 parts piperazine pyrophosphate, and 1-1.5 parts laser marking agent.

[0008] This invention achieves flame retardancy through the interaction between brominated flame retardant (DBDPE), antimony trioxide (ATO), and melamine cyanurate (MCA). The thermal decomposition temperature of MCA is close to that of DBDPE, effectively ensuring the generation of sufficient flame-retardant gases during the smoke phase, carrying away heat and diluting oxygen, resulting in excellent flame retardant performance. Simultaneously, the interaction between ammonium polyphosphate and piperazine pyrophosphate effectively promotes the self-decomposition and foaming of the resin and the self-generated char, enhancing color development and significantly improving the laser marking performance of polyolefin materials.

[0009] The polyolefin resin described in this invention exhibits a melt flow rate of 0.5–50 g / 10 min under test conditions of 230°C and 2.16 kg. The test standard refers to GB / T3682.1-2018.

[0010] Preferably, the bromine-based flame retardant is a decabromine flame retardant, which includes decabromodiphenyl ethane.

[0011] Preferably, the melamine cyanurate has a pH < 7 and a thermal decomposition temperature greater than 320°C.

[0012] Preferably, the melamine cyanurate is synthesized by a solid-phase method.

[0013] Preferably, the ammonium polyphosphate is melamine-coated ammonium polyphosphate, wherein the melamine coating amount is 1-10% and the degree of polymerization of polyphosphate is <1000.

[0014] More preferably, the melamine coating content in the ammonium polyphosphate is 3-10%.

[0015] Preferably, the polyolefin resin includes one or more copolymers of polyethylene (HDPE, LDPE, LLDPE, metallocene PE), polypropylene, ethylene-ethyl acetate copolymer, and ethylene-octene copolymer.

[0016] Preferably, the content of the phosphate dimer of the piperazine pyrophosphate is >94%.

[0017] Preferably, the piperazine pyrophosphate is synthesized by dehydration condensation of piperazine diphosphate.

[0018] The ammonium polyphosphate of this invention is coated with melamine, which gives it excellent flowability. Furthermore, the use of a lower molecular weight ammonium polyphosphate allows it to accumulate in large quantities on the material surface during injection molding. When laser energy is applied to the material surface, a carbonization reaction occurs efficiently under the catalysis of a piperazine pyrophosphate charring agent, deepening the color of the laser-marked area. In addition, the decomposition and carbonization reaction of the ammonium polyphosphate and piperazine pyrophosphate generates a large amount of small molecule gas, significantly increasing the size of the laser-marked area and improving the clarity of the laser marking.

[0019] Preferably, the laser marking agent is a mixture of tin oxide and antimony oxide, wherein the tin oxide content is >90%.

[0020] To maximize the laser marking effect, this invention also adds laser absorbers such as antimony tin oxide. By controlling the content of tin oxide, the absorption of laser energy (1064nm laser) can be better promoted.

[0021] Preferably, the polyolefin material further includes the following components in parts by weight: 0.1 to 2 parts of antioxidant and 0.1 to 3 parts of processing aid.

[0022] Preferably, the antioxidant is selected from one or a mixture of several of the following: phenolic antioxidants, phosphite antioxidants, divalent sulfur antioxidants, and hindered amine antioxidants.

[0023] The phenolic antioxidants can be selected from antioxidant 264, antioxidant 1010, antioxidant 1076, antioxidant SP, antioxidant 2246, antioxidant CA, antioxidant 330, Irganox 1890, or antioxidant 3114; the phosphites can be selected from antioxidant TNP, antioxidant ODP, antioxidant 168, Irganox 1093, or Irganox 1222; the divalent sulfur antioxidants can be selected from dilaurate thiodipropionate (DLTP) or distearate thiodipropionate (DSTP); and the hindered amine antioxidants can be selected from LS-744, LS-770, GW-540, or Flamstab NOR116.

[0024] Preferably, the processing aid is selected from one or more of low molecular weight lipids, metal soaps, stearic acid complex esters, and amides.

[0025] The low molecular weight lipids can be selected from solid paraffin, liquid paraffin, or low molecular weight polyolefin wax; the metal soaps can be selected from calcium stearate, magnesium stearate, zinc stearate, or barium stearate; the stearic acid complex esters can be selected from ethylene glycol stearate, glyceryl stearate, or pentaerythritol stearate; and the amides can be selected from erucamide, methyl bis-stearamide, or N,N-ethylene bis-stearamide.

[0026] In the polyolefin material of the present invention, the content of polyolefin resin is not less than 40 wt%.

[0027] This invention also claims protection for a method for preparing the polyolefin material, comprising the following steps:

[0028] All components are mixed once, then melt-extruded, granulated, and dried through a twin-screw extruder to obtain a one-step polyolefin material. The one-step polyolefin material is then mixed a second time, melt-extruded, and granulated through a single-screw extruder to obtain the flame-retardant polyolefin material.

[0029] Preferably, the mixing speed is 500-1500 rpm and the time is 3-8 min.

[0030] Preferably, the secondary mixing speed is 100-300 rpm and the time is 10-20 min.

[0031] Preferably, the temperature for melt extrusion and granulation of the twin-screw extruder is 180-200℃.

[0032] Preferably, the temperature for melt extrusion and granulation of the single-screw extruder is 170–210°C.

[0033] The present invention also claims protection for the use of the aforementioned polyolefin material in the preparation of laser marking materials.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] This invention utilizes the interaction between various components such as brominated flame retardants, antimony trioxide, melamine cyanurate, ammonium polyphosphate, and piperazine pyrophosphate to effectively improve the laser marking performance of polypropylene resin while ensuring that the polypropylene material has high flame retardant properties. Detailed Implementation

[0036] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0037] Unless otherwise specified, the experimental methods used in the following examples and comparative examples are conventional methods. Unless otherwise specified, the antioxidants and processing aids are commercially available, and the same antioxidants and processing aids are used in parallel experiments.

[0038] The raw materials used in the examples and comparative examples are shown in Table 1.

[0039] Table 1

[0040]

[0041]

[0042] Examples 1-12 and Comparative Examples 1-11

[0043] The components and weight parts of the polyolefin materials of Examples 1-12 and Comparative Examples 1-11 are shown in Tables 2-3.

[0044] The preparation methods of the polyolefin materials in Examples 1-12 and Comparative Examples 1-11 include the following steps:

[0045] After weighing each component according to the proportion, the components are mixed evenly in a high-speed mixer, and then melt-extruded and granulated at 180-200℃ through a twin-screw extruder. After drying, a one-step polyolefin material is obtained. Then, the one-step polyolefin material is mixed evenly in a low-speed mixer, and then melt-extruded and granulated at 170-210℃ through a single-screw extruder to obtain the polyolefin material.

[0046] Table 2 shows the component amounts (parts by weight) in the examples.

[0047]

[0048] Table 3. Component dosage (parts by weight) in the comparative examples

[0049]

[0050] Performance testing

[0051] For the sample preparation for evaluating laser marking performance, the polyolefin material prepared in the examples and comparative examples was first injection molded into a plastic square plate with dimensions of 100*30*2mm. Then, a 1064mm infrared laser with an output power of 20W and a scanning speed of 1000mm / s was used to rapidly mark 20*20mm square symbols. Finally, the LAB value before marking was compared with the LAB value of the square area after marking, and the change in color difference ΔE was obtained as the evaluation value of laser marking performance. The larger the ΔE, the greater the color difference before and after laser marking, indicating better laser marking performance.

[0052] To evaluate the clarity of laser marking, using the same sample and laser marking conditions, the letters "18A", "22A", and "28A" were quickly marked. Under the same marking conditions, the markings were observed under a microscope at 20x magnification to determine if the letters formed continuous markings. The width of the number "1" was also measured. This was used to evaluate the clarity of the laser marking. Continuous laser markings for the letters and a wider "1" indicate higher laser marking clarity.

[0053] Flame retardant performance: tested according to the UL 94-2020 test standard for vertical burning.

[0054] The performance test results are shown in Table 4.

[0055] Table 4 Performance test results for each group

[0056]

[0057] As can be seen from the data in Table 4, the polyolefin material prepared by the embodiments of the present invention has high laser marking performance and flame retardant performance. The color difference value ΔE after laser marking can be maintained in the range of above 40, the width of the laser-marked font can be maintained in the range of 1.85-1.99mm, and the lettering is continuous after laser marking. At the same time, the flame retardant performance of the polyolefin material prepared by the embodiments of the present invention can be maintained at the V-0 level.

[0058] In Comparative Example 1, the polyolefin material prepared without melamine cyanurate showed low laser marking color difference, small laser marking letter width, and low laser marking clarity. Furthermore, its 0.8mm UL-94 vertical flammability rating only reached V-2. In Comparative Example 2 and Comparative Example 3, the polyolefin materials prepared without ammonium polyphosphate and piperazine pyrophosphate showed low laser marking color difference, discontinuous laser marking lettering, small letter width, and poor laser marking clarity. These polyolefin materials also only achieved a V-2 flame retardant rating in the 0.8mm specification combustion test. In Comparative Example 4, the polyolefin material prepared without laser marking agent exhibited poor laser marking performance. In Comparative Example 5, the excessive weight percentage of melamine cyanurate reduced its synergistic flame retardant effect, resulting in excessive... Multi-phase gaseous processes dilute the concentration of antimony bromide and reduce the char formation, resulting in poor laser marking performance of the prepared polyolefin material. In Comparative Examples 6-7, the weight percentage of ammonium polyphosphate added was unsuitable, leading to poor laser marking performance of the prepared polyolefin material. In Comparative Examples 8-9, the weight percentage of piperazine pyrophosphate added was unsuitable, resulting in poor laser marking performance of the prepared polyolefin material. When the weight percentage of piperazine pyrophosphate added was too low, not only would the laser marking performance be reduced, but its flame retardant properties would also deteriorate. In Comparative Example 10, the weight percentage of laser marking agent added was too low, resulting in poor laser marking performance. In Comparative Example 11, the weight percentage of laser marking agent added was too high, making it difficult for the components to disperse effectively. The surface energy absorption would not increase; instead, it would affect the foaming effect of the material surface, thus reducing laser marking performance.

[0059] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A polyolefin material, characterized in that, It includes the following components by weight: 50-70 parts of polyolefin resin, 15-24 parts of brominated flame retardant, 4-10 parts of antimony trioxide, 1-5 parts of melamine cyanurate, 3-15 parts of ammonium polyphosphate, 1-5 parts of piperazine pyrophosphate, and 0.2-2 parts of laser marking agent; The thermal decomposition temperature of the melamine cyanurate is greater than 320°C; the laser marking agent is a mixture of tin oxide and antimony oxide, wherein the tin oxide content is >90%; the bromine-based flame retardant includes decabromoflammable retardants or tetrabromobisphenol A-bis(2,3-dibromopropyl ether).

2. The polyolefin material as described in claim 1, characterized in that, It includes the following components by weight: 60-65 parts polyolefin resin, 18-20 parts bromine flame retardant, 7-8 parts antimony trioxide, 3-4 parts melamine cyanurate, 8-10 parts ammonium polyphosphate, 2-3 parts piperazine pyrophosphate, and 1-1.5 parts laser marking agent.

3. The polyolefin material as described in claim 1, characterized in that, It must include at least one of the following (1) to (2): (1) The decabromoflame retardant includes decabromodiphenyl ethane; (2) The pH of the melamine cyanurate is <7.

4. The polyolefin material as described in claim 1, characterized in that, The ammonium polyphosphate is melamine-coated ammonium polyphosphate, wherein the melamine coating amount is 3-10% and the degree of polymerization of polyphosphate is <1000.

5. The polyolefin material as described in claim 1, characterized in that, It includes at least the following (1) to (2): One of the following: (1) The polyolefin resin includes one or more copolymers of polyethylene, polypropylene, ethylene-ethyl acetate copolymer, and ethylene-octene copolymer; (2) The content of phosphate dimer of the piperazine pyrophosphate is >94%.

6. The polyolefin material as described in claim 1, characterized in that, The polyolefin material also includes the following components in parts by weight: 0.1 to 2 parts antioxidant and 0.1 to 3 parts processing aid.

7. The polyolefin material as described in claim 6, characterized in that, It must include at least one of the following (1) to (2): (1) The antioxidant is selected from one or a mixture of several of the following: phenolic, phosphite, divalent sulfur, hindered amine antioxidants; (2) The processing aid is selected from one or more of low molecular weight lipids, metal soaps, stearic acid complex esters, and amides.

8. A method for preparing a polyolefin material as described in any one of claims 1 to 7, characterized in that, Includes the following steps: All components are mixed once, then melt-extruded, granulated, and dried through a twin-screw extruder to obtain a one-step polyolefin material. The one-step polyolefin material is then mixed a second time, melt-extruded, and granulated through a single-screw extruder to obtain the flame-retardant polyolefin material.

9. The preparation method according to claim 8, characterized in that, Includes one of the following (1) to (4): (1) The rotation speed of the first mixing is 500-1500 rpm and the time is 3-8 min; (2) The rotation speed of the secondary mixing is 100-300 rpm and the time is 10-20 min; (3) The temperature for melt extrusion and granulation of the twin-screw extruder is 180-200℃; (4) The temperature of the single screw extruder for melt extrusion and granulation is 170-210℃.

10. The application of a polyolefin material as described in any one of claims 1 to 7 in the preparation of laser marking materials.

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