Low precipitation and high glow-wire resistant toughened POM composition, and preparation method therefor and use thereof

Abstract

Disclosed in the present invention are a low precipitation and high glow-wire resistant toughened POM composition, and a preparation method therefor and a use thereof. The POM composition comprises the following components in parts by weight: 100 parts of POM resin; 20-30 parts of thermoplastic polyurethane elastomer; and 10-20 parts of synergistic masterbatch. The synergistic masterbatch comprises the following components in percentage by weight: 50%-70% of polyamide and 30%-50% of melamine cyanurate. According to the present invention, the melamine cyanurate is pre-coated with the polyamide to form the synergistic masterbatch, and then the synergistic masterbatch is mixed with the thermoplastic polyurethane elastomer, thereby reducing the degradation of POM during extrusion. In this way, a low precipitation and high glow-wire resistant toughened POM composition is prepared, the glow-wire flammability index thereof can reach 650°C / 2.0mm, and the mold deposit is not prone to generating during processing.

Description

A low precipitation, high glow-wire toughened POM composition and its preparation method and application Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a low-precipitation, high-glow-wire toughened POM composition, a preparation method thereof, and applications thereof. Background Art

[0002] Polyoxymethylene (POM, as named by IUPAC) is a highly crystalline engineering plastic with excellent mechanical properties, good wear resistance, and creep resistance. It is widely used in electronics, industrial machinery, office equipment, home appliances, automobiles and other fields.

[0003] However, the glow-wire flammability index of POM resin is relatively low. This is especially true for POM materials used in electrical components, which require excellent glow-wire performance, generally requiring a glow-wire flammability index (GWFI) of 650°C / 2.0mm. However, the current GWFI of POM resin can only reach 550°C, far below the requirement. Moreover, since POM resin is a highly crystalline polymer, it has poor compatibility with other additives, resulting in easy precipitation during the preparation process.

[0004] Therefore, there is an urgent need to obtain a toughened POM composition with low precipitation and high glow-wire properties. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, the present invention aims to provide a toughened POM composition with low precipitation and high glow-wire properties, as well as its preparation method and application. The POM composition provided by the present invention has both high glow-wire and low precipitation properties.

[0006] The technical solution adopted in the present invention is:

[0007] A low-precipitation, high-glow-wire toughened POM composition, characterized by comprising the following components, by weight: 100 parts of POM resin; 20-30 parts of thermoplastic polyurethane elastomer; 10-20 parts of synergistic masterbatch;

[0008] The synergistic masterbatch comprises the following components in percentage by weight: 50%-70% of polyamide and 30%-50% of melamine cyanurate.

[0009] The weight portion of the thermoplastic polyurethane elastomer is 20-30 parts, for example, it can be 22 parts, 24 parts, 26 parts, 28 parts, and specific points between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the range.

[0010] The weight proportion of the synergistic masterbatch is 10-20 parts, for example, it can be 12 parts, 14 parts, 16 parts, 18 parts, and specific values ​​between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the range.

[0011] Preferably, the synergistic masterbatch comprises the following components in percentage by weight: 60% polyamide and 40% melamine cyanurate.

[0012] Preferably, the polyamide is a polyamide resin having a melting point between 145-170°C.

[0013] Preferably, the POM resin has a melt index of 2.5-27 g / 10 min at 190° C. and 2.16 kg. The POM resin can be selected from homopolymer POM and / or copolymer POM, and the mass percentage of the POM resin in the composition is not less than 65%.

[0014] Preferably, according to the test standard ISO 7619-1, the Shore hardness of the thermoplastic polyurethane elastomer is 80-90A.

[0015] Preferably, the Shore hardness of the thermoplastic polyurethane elastomer is 85A.

[0016] Preferably, the POM composition further comprises a primary antioxidant and a secondary antioxidant; the primary antioxidant is a hindered phenol antioxidant, and the secondary antioxidant is a phosphate antioxidant.

[0017] The POM composition of the present invention may further contain other additives such as lubricants, nucleating agents, and weathering agents.

[0018] The present invention also provides a method for preparing the low precipitation, high glow-wire toughened POM composition, comprising the following steps:

[0019] S1: Preparation of synergistic masterbatch;

[0020] S2: POM resin, thermoplastic polyurethane elastomer, synergistic masterbatch, primary antioxidant and secondary antioxidant are mixed in a high-speed mixer for 1-2 minutes to obtain a premix;

[0021] S3: The premix is ​​melt-extruded at 150° C. to 200° C. through a twin-screw extruder, cooled, and granulated to obtain a POM composition.

[0022] Preferably, in step S1, the method for preparing the synergistic masterbatch comprises: adding polyamide and melamine cyanurate together into a high-speed mixer and mixing for 2 to 5 minutes to obtain a premix; melt-extruding the premix through a twin-screw extruder at 160 to 210° C., cooling, and granulating to obtain the synergistic masterbatch.

[0023] The present invention also provides an application of the low-precipitation, high-glow-wire toughened POM composition in electrical components, for example, it can be used to prepare electrical products, electronic components, electrical appliance management peripheral components, etc.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention pre-coates melamine cyanurate with polyamide to form a synergistic masterbatch, and then mixes the synergistic masterbatch with a thermoplastic polyurethane elastomer (TPU). This reduces the degradation of POM during the extrusion process, thereby preparing a toughened POM composition with low precipitation and high glow-wire flammability. The glow-wire flammability index can reach 650°C / 2.0mm, and mold deposit is not easily generated during the processing. DETAILED DESCRIPTION

[0026] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0027] <Preparation of Examples and Comparative Examples>

[0028] The raw materials used in the examples and comparative examples of the present invention are all commercially available, including:

[0029] POM resin: POM M25-44, melt index 2.5 g / 10 min, purchased from DuPont, USA;

[0030] POM resin: POM M90-44, melt index 9 g / 10 min, purchased from Nantong Baotai Ling;

[0031] POM resin: POM M270-44, melt index 27 g / 10 min, purchased from Nantong Baotai Ling;

[0032] POM resin: POM 500P, melt index 15g / 10min, purchased from DuPont, USA;

[0033] POM resin: POM 100P, melt index 2.6 g / 10 min, purchased from DuPont, USA;

[0034] POM resin: POM C13021, melt index 13 g / 10 min, purchased from Celanese;

[0035] Thermoplastic polyurethane elastomer (TPU): model AVALON 80AB, Shore hardness 80A, purchased from Huntsman;

[0036] Thermoplastic polyurethane elastomer (TPU): model AVALON 85AB, Shore hardness 85A, purchased from Huntsman;

[0037] Thermoplastic polyurethane elastomer (TPU): model AVALON 90AB, Shore hardness 90A, purchased from Huntsman;

[0038] Melamine cyanurate: model MCA, purchased from Shandong Haiwang Chemical;

[0039] The synergistic masterbatch A is composed of the following components in percentage by weight: polyamide resin (model ES-4, melting point 145° C., purchased from Shanghai Zhenwei Composite Materials): 60%, melamine cyanurate: 40%.

[0040] The synergistic masterbatch B is composed of the following components in percentage by weight: polyamide resin (model ES-6, melting point 170° C., purchased from Shanghai Zhenwei Composite Materials): 60%, melamine cyanurate: 40%.

[0041] The melamine cyanurate used in synergistic masterbatch A and synergistic masterbatch B is the same product.

[0042] The main antioxidant was antioxidant 245, purchased from BASF (China) Co., Ltd.

[0043] The secondary antioxidant was antioxidant 168, purchased from BASF (China) Co., Ltd.

[0044] The synergistic masterbatch is prepared by adding polyamide resin and melamine cyanurate together into a high-speed mixer and mixing for 2 to 5 minutes to obtain a premix; then, melt-extruding the premix through a twin-screw extruder at 160 to 210°C, cooling, and granulating to obtain the synergistic masterbatch. The screw barrel temperatures of the twin-screw extruder from the feed port to the die are: 160°C-170°C, 170°C-180°C, 170°C-190°C, 170°C-200°C, 170°C-200°C, 170°C-200°C, 170°C-200°C, 170°C-200°C, 170°C-200°C, 170°C-200°C, and 170°C-210°C, the screw speed is 200 to 300 rpm, the feed rate is 50 to 200 kg / h, and the vacuum degree is -0.1 to 0 MPa.

[0045] The formulations of the POM compositions of Examples 1 to 10 and Comparative Examples 1 to 6 are shown in Tables 1 to 2, and the preparation methods are as follows:

[0046] S1: POM resin, thermoplastic polyurethane elastomer, synergistic masterbatch, primary antioxidant and secondary antioxidant are mixed in a high-speed mixer for 1-2 minutes to obtain a premix;

[0047] S2: The premix is ​​melt-extruded through a twin-screw extruder at 150°C-200°C, cooled, and granulated to obtain a POM composition. The temperatures of the barrels of the twin-screw extruder from the feed port to the die are: 150°C-170°C, 170°C-180°C, 170°C-190°C, 170°C-200°C, 170°C-200°C, 170°C-200°C, 170°C-200°C, 170°C-200°C, 170°C-200°C, 170°C-200°C, 170°C-200°C, 170°C-200°C, 170°C-200°C, 170°C-200°C, the screw speed is 200-300 rpm, the feed rate is 50-200 kg / h, and the vacuum degree is -0.1-0 MPa.

[0048] <Test Standard>

[0049] Glow Wire GWFI: Test standard IEC 60695-2-12:2014, sample thickness 2.0mm;

[0050] Notched impact strength: test standard ISO 180:2013, pendulum energy 2.75J;

[0051] Extrusion granulation: observe the condition of the particles during the extrusion process. Normal particles have an intact surface, 1 to 2 vacuum holes in the middle, and are not crushed. Foamed particles are expanded or crushed.

[0052] Mold Deposits: The extruded material is dried at 90°C for 4 hours, then injection molded at 200°C. After 4 hours of continuous injection molding, the weight change of the mold deposit collector at the exhaust port is measured. The greater the weight, the more likely the material is to produce mold deposits.

[0053] Evaluation method of constant temperature quality retention rate: the quality retention rate of constant temperature thermal weight loss under air conditions is used for evaluation. The sample is heated to 230℃ at 20℃ / min under air conditions, and then kept at 230℃ for 1 hour. The higher the quality retention rate, the better the thermal stability.

[0054] Table 1. Formula of Examples 1 to 11 (parts by weight)

[0055] Table 2. Comparative Examples 1-6 Formula (parts by weight)

[0056] Table 3. Performance test results of Examples 1-11

[0057] Table 4. Performance test results of comparative examples 1-6

[0058] Result analysis:

[0059] Comparison of Example 2 and Comparative Examples 1-2 shows that the addition amount of the thermoplastic polyurethane elastomer affects the toughness, glow-wire performance, and processing properties of the composition, and the composition prepared within the addition amount range provided by the present invention has better toughness, glow-wire performance, and processing properties.

[0060] Comparison of Example 2 and Comparative Examples 3-4 shows that the amount of synergistic masterbatch added affects the toughness, glow-wire performance, and processability of the composition. When the synergistic masterbatch content is too low, the composition exhibits low glow-wire performance, while when the synergistic masterbatch content is too high, the composition's toughness and processability decrease. Compositions prepared within the range of synergistic masterbatch content provided by the present invention exhibit excellent toughness, glow-wire performance, and processability.

[0061] Comparison of Example 2 with Comparative Example 5 shows that if polyurethane and melamine cyanurate are directly added to the composition without coating treatment, decomposition and foaming will occur during the extrusion granulation process, making continuous production impossible and greatly reducing its practicality.

[0062] Comparison of Example 2 and Comparative Example 6 shows that without the synergistic masterbatch, the composition exhibits low glow-wire performance, with a GWFI of only 600°C at 2.0mm, failing to meet application requirements. However, the addition of the synergistic masterbatch of the present invention effectively reduces POM degradation during extrusion. Furthermore, the resulting toughened POM composition exhibits high glow-wire performance, with a glow-wire flammability index reaching 650°C / 2.0mm.

[0063] To investigate the effect of the composition ratio of the synergistic masterbatch on the performance of the composition, experimental groups 1 to 3 (see Table 5) were set up. Synergistic masterbatches were prepared according to the weight percentage formulations of experimental groups 1 to 3, and then POM compositions were prepared according to the formulation and method of Example 2. The performance of the POM compositions prepared using the synergistic masterbatch from each experimental group was tested, and the results are shown in Table 5.

[0064] Table 5

[0065] As can be seen from Table 5, the component ratio in the synergistic masterbatch of the present invention will affect the toughness of the POM composition, among which the composition prepared with the synergistic masterbatch of test group 2 has better comprehensive performance.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A low precipitation, high glow-wire toughened POM composition, characterized in that: The composition comprises the following components by weight: 100 parts of POM resin; 20-30 parts of thermoplastic polyurethane elastomer; 10-20 parts of synergistic masterbatch; The synergistic masterbatch comprises the following components in percentage by weight: 50%-70% of polyamide and 30%-50% of melamine cyanurate.

2. The low precipitation, high glow-wire toughened POM composition according to claim 1, characterized in that: The synergistic masterbatch comprises the following components in percentage by weight: 60% of polyamide and 40% of melamine cyanurate.

3. The low precipitation, high glow-wire toughened POM composition according to claim 1, characterized in that: The polyamide is a polyamide resin with a melting point between 145-170°C.

4. The low precipitation, high glow-wire toughened POM composition according to claim 1, characterized in that: The POM resin has a melt index of 2.5-27 g / 10 min under the test conditions of 190° C. and 2.16 kg.

5. The low precipitation, high glow-wire toughened POM composition according to claim 1, characterized in that: The Shore hardness of the thermoplastic polyurethane elastomer is 80-90A.

6. The low precipitation, high glow-wire toughened POM composition according to claim 1, characterized in that: The Shore hardness of the thermoplastic polyurethane elastomer is 85A.

7. The low precipitation, high glow-wire toughened POM composition according to claim 1, characterized in that: The POM composition also includes a primary antioxidant and a secondary antioxidant; the primary antioxidant is a hindered phenol antioxidant; and the secondary antioxidant is a phosphate antioxidant.

8. The method for preparing the toughened POM composition with low precipitation and high glow wire according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: Preparation of synergistic masterbatch; S2: uniformly mixing the POM resin, the thermoplastic polyurethane elastomer, the synergistic masterbatch, the primary antioxidant and the secondary antioxidant in a high-speed mixer to obtain a premix; S3: The premix is ​​melt-extruded at 150° C. to 200° C. through a twin-screw extruder, cooled, and granulated to obtain a POM composition.

9. The method for preparing the toughened POM composition with low precipitation and high glow wire according to claim 8, characterized in that: In step S1, the preparation method of the synergistic masterbatch includes: adding polyamide and melamine cyanurate into a high-speed mixer and mixing them uniformly to obtain a premix; melt-extruding the premix at 160 to 210° C. through a twin-screw extruder, cooling, and granulating to obtain the synergistic masterbatch.

10. Use of the low precipitation, high glow-wire toughened POM composition according to any one of claims 1 to 8 in electrical components.

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