Low-gloss and low-noise POM composition as well as preparation method and application thereof

Abstract

The invention discloses a low-gloss and low-noise POM (Polyoxymethylene) composition as well as a preparation method and application thereof. The POM composition is prepared from the following components in parts by weight: 100 parts of POM resin, 15 to 30 parts of wear-resistant master batch, 10 to 20 parts of styrene-butadiene-styrene block copolymer and 0.8 to 4 parts of silicone oil, the wear-resistant master batch is a composition of linear low-density polyethylene, polytetrafluoroethylene and silicone, and the content percentage of each component is as follows: 35 to 55 percent of linear low-density polyethylene, 10 to 30 percent of polytetrafluoroethylene and 35 to 55 percent of silicone; the styrene-butadiene-styrene block copolymer is a star polymer. The POM material is low in glossiness, low in friction coefficient, excellent in friction performance and low in noise in the using process.

Description

Technical Field

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

[0002] POM (polyoxymethylene resin), one of the five major engineering plastics, is one of the most widely used polymers. It is a thermoplastic crystalline polymer with no side chains, a high density, and highly crystalline linear polymer. It is widely used in products such as gears and bearings. However, high-gloss POM materials can cause surface glare during use, which can lead to visual fatigue and reduced user comfort. To achieve a high gloss, the material may require multiple polishing processes, which can lead to microscopic surface unevenness and a decrease in frictional performance. This makes it more susceptible to surface scratches and wear, thus reducing the overall appearance of the product. Furthermore, when POM products come into contact with each other or rub against other materials, the excessively smooth surface of high-gloss POM materials can generate high noise levels during friction, significantly impacting applications with stringent noise requirements, such as automotive interiors and office equipment. Therefore, when designing materials, it is important to comprehensively consider customer requirements for gloss, frictional performance, and noise reduction to provide products that better meet market demands. Summary of the Invention

[0003] In view of the defects in the prior art, the present invention discloses a low-gloss, low-noise POM composition and a preparation method and application thereof.

[0004] The present invention provides a low-gloss, low-noise POM composition, which comprises the following components in parts by weight:

[0005] 100 parts of POM resin;

[0006] 15-30 parts of wear-resistant masterbatch, preferably 18-25 parts;

[0007] 10 to 20 parts, preferably 12 to 18 parts, of styrene-butadiene-styrene block copolymer;

[0008] 0.8 to 4 parts of silicone oil, preferably 1 to 3 parts.

[0009] The mass percentage of the POM value is not less than 65%.

[0010] Furthermore, the wear-resistant masterbatch is a composition of linear low-density polyethylene, polytetrafluoroethylene and silicone, and the wear-resistant masterbatch can reduce wear loss during friction.

[0011] The percentage of each component in the wear-resistant masterbatch relative to the total weight of the wear-resistant masterbatch is: linear low-density polyethylene (LLDPE) 35-55%, polytetrafluoroethylene (PTFE) 10-30%, and silicone 35-55%. LLDPE serves as the carrier of the wear-resistant masterbatch. Too little LLDPE increases the difficulty of masterbatch production and hinders the dispersion of other components. Too much silicone can cause precipitation, deteriorating the appearance of the injection-molded part. Adding PTFE to the wear-resistant masterbatch can improve the appearance and noise issues caused by the addition of silicone. Too little PTFE can negatively impact gloss, while too much can significantly reduce material performance.

[0012] Furthermore, the styrene-butadiene-styrene block copolymer (SBS) is a star-shaped polymer, wherein the styrene content is 30% to 75%, preferably 30% to 40%. SBS can form unevenness on the surface of the material, thereby achieving a low-gloss effect. At the same time, it improves the softness of the material, absorbs more energy during the friction process, and achieves the effect of reducing noise. If the amount of SBS added is too high, the material performance will be reduced, and the gloss of the material will not be further reduced. If the amount of SBS added is too low, the gloss reduction of the material is not obvious, and the linear SBS gloss reduction effect is not good.

[0013] Furthermore, the POM resin has a melt flow rate of 1.5 to 30 g / 10 min, preferably 2.5 to 14 g / 10 min (ISO 1133-1-2011, test conditions 190° C., 2.16 kg).

[0014] Furthermore, the silicone oil is any one of hydroxy silicone oil, long-chain alkyl silicone oil (C12 or greater), or phenyl silicone oil. Silicone oil acts like a plasticizer, reducing intermolecular forces. It also migrates to the sample surface, forming a lubricating film that reduces friction and noise.

[0015] Furthermore, the weight average molecular weight of the silicone oil is ≤6000, and the weight average molecular weight of the silicone is ≥200000. The molecular weight is measured by gel permeation chromatography (GPC).

[0016] Furthermore, the POM composition further comprises a processing aid, which is one or more of a primary antioxidant, a secondary antioxidant, a formaldehyde absorber, and a weathering agent; and the weight portion of the processing aid is 0 to 1 part.

[0017] The present invention also provides a preparation method of the POM composition, comprising the following steps: weighing each component by weight, mixing silicone oil with a styrene-butadiene-styrene block copolymer component, then adding POM resin and wear-resistant masterbatch and mixing in a high-speed mixer, melt-extruding through a twin-screw extruder, cooling, and granulating to obtain the POM composition.

[0018] Furthermore, the melting temperature is 150°C to 200°C.

[0019] The present invention also provides a preparation method of the wear-resistant masterbatch, comprising the following steps: adding linear low-density polyethylene, silicone and polytetrafluoroethylene together into a high-speed mixer and mixing for 2 to 5 minutes to obtain a premix; and melt-extruding the premix through a twin-screw extruder at 140 to 180° C., cooling and granulating to obtain the wear-resistant masterbatch.

[0020] The present invention also provides the use of the POM composition in the preparation and production of automobiles, home appliances, electronic and electrical products or daily necessities, such as gears, racks, slide rails, etc.

[0021] In summary, compared with the prior art, the present invention achieves the following technical effects:

[0022] (1) The POM composition of the present invention can reduce the noise generated during the use of the material while reducing the gloss.

[0023] (2) The POM composition of the present invention has a low friction coefficient, small wear, a simple preparation process, and a wide range of material applications. DETAILED DESCRIPTION

[0024] In order to help those skilled in the art better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention are clearly and completely described below. 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 those skilled in the art without making any creative efforts should fall within the scope of protection of the present invention.

[0025] Example

[0026] The present invention is further described below with reference to specific examples and comparative examples. The following specific examples are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following examples, and are particularly not limited to the types of the various component raw materials used in the following specific examples.

[0027] <Sources of Raw Materials for Examples and Comparative Examples>

[0028] POM resin A: melt flow rate of 2.5 g / 10 min, brand POM M25-44, purchased from Polyplastics of Japan;

[0029] POM resin B: melt flow rate of 14 g / 10 min, brand POM M140-44, purchased from Polyplastics of Japan;

[0030] POM resin C: melt flow rate of 1.8 g / 10 min, brand POM 2010, purchased from Asahi Kasei;

[0031] POM resin D: melt flow rate of 27 g / 10 min, brand POM M270-44, purchased from Polyplastics of Japan;

[0032] POM resin E: melt flow rate of 9 g / 10 min, brand POM M90-44, purchased from Polyplastics of Japan;

[0033] Linear low-density polyethylene: brand 6101XR, purchased from Sinopec;

[0034] High-density polyethylene: brand HDPE 5000S, purchased from Daqing Petrochemical;

[0035] Low-density polyethylene: brand LDPE 2420H, purchased from Maoming Petrochemical;

[0036] Polytetrafluoroethylene: brand F-5AEX R, purchased from Solvay;

[0037] Silicone: brand BZP200, purchased from Chongqing Baozhuan;

[0038] Wear-resistant masterbatch A: linear low-density polyethylene 40%, polytetrafluoroethylene 10%, silicone 50%;

[0039] Wear-resistant masterbatch B: linear low-density polyethylene 45%, polytetrafluoroethylene 15%, silicone 40%;

[0040] Wear-resistant masterbatch C: linear low-density polyethylene 30%, polytetrafluoroethylene 5%, silicone 65%;

[0041] Wear-resistant masterbatch D: high-density polyethylene 40%, polytetrafluoroethylene 10%, silicone 50%;

[0042] Wear-resistant masterbatch E: low-density polyethylene 40%, polytetrafluoroethylene 10%, silicone 50%;

[0043] Wear-resistant masterbatch F: 8 parts of linear low-density polyethylene, 10 parts of silicone;

[0044] Styrene-butadiene-styrene (SBS) block copolymer A: KTR-401, star-shaped, styrene content 31%, purchased from Kumho, South Korea;

[0045] Styrene-butadiene-styrene (SBS) block copolymer B: SBS YH-815, star-shaped, styrene content 40%, purchased from Baling Petrochemical;

[0046] Styrene-butadiene-styrene (SBS) block copolymer C: 8132, star-shaped, styrene content 75%, purchased from Guangdong Zhonghe Plastics;

[0047] Styrene-butadiene-styrene (SBS) block copolymer D: brand SBS YH 792, linear, styrene content 40%, purchased from Baling Petrochemical;

[0048] Silicone oil A: hydroxy silicone oil, brand TZ1301, purchased from Tangze Chemical;

[0049] Silicone oil B: phenyl silicone oil, brand Zinca 255, purchased from Anhui Xinjia;

[0050] Processing aid: antioxidant JYANOX-245, commercially available, the same commercial product was used in parallel experiments.

[0051] <Preparation method>

[0052] The preparation method of the POM composition of the embodiment of the present invention and the comparative example comprises the following steps:

[0053] S1: According to the ratios in Tables 1 and 2, silicone oil and styrene-butadiene-styrene block copolymer were weighed and premixed for 3 to 5 minutes, and then mixed with POM resin and wear-resistant masterbatch in a high-speed mixer for 1 to 2 minutes to obtain a premix.

[0054] S2: The premix in step S1 is put into a twin-screw extruder, melt-extruded, cooled, and granulated to obtain a POM composition.

[0055] The temperatures of each screw barrel of the twin-screw extruder from the feeding port to the die are: 150℃~170℃, 170℃~180℃, 170℃~190℃, 170℃~200℃, 170℃~200℃, 170℃~200℃, 170℃~200℃, 170℃~200℃, 170℃~200℃, 170℃~200℃, 170℃~200℃, the screw speed is 200 rpm~300 rpm, the feed rate is 50kg / h-200kg / h, and the vacuum degree is (-0.1)~0MPa.

[0056] The preparation method of the POM composition of Comparative Example 5 is different from that of Example 1 in that linear low-density polyethylene and silicone are prepared into wear-resistant masterbatch F, and polytetrafluoroethylene is then added separately.

[0057] The preparation method of the wear-resistant masterbatch is as follows: linear low-density polyethylene, silicone and polytetrafluoroethylene are added together in a high-speed mixer and mixed for 2 to 5 minutes to obtain a premix; the premix is ​​melt-extruded at 140 to 180° C. through a twin-screw extruder, cooled and granulated to obtain the wear-resistant masterbatch.

[0058] <Test Standard>

[0059] The performance test standards of the embodiments and comparative examples of the present invention are as follows:

[0060] (1) Glossiness evaluation: The granulated pellets were dried at 90-100°C for 4-6 hours and then injection molded into 100*100*2.0 mm square plates at 200°C. The plates were then tested using a gloss meter.

[0061] (2) Friction coefficient and wear resistance evaluation: Friction between plastics, plastic multifunctional friction tester, load 3.88N, speed 200rpm, test time 120min.

[0062] (3) Noise evaluation: The friction between plastics is tested using a multifunctional plastic friction tester with a load of 3.88 N and a rotation speed of 200 rpm. The noise generated during the friction process is tested using a decibel meter.

[0063] Table 1 Example of each group distribution ratio (weight parts)

[0064]

[0065]

[0066] Table 2 Comparative Example Distribution Ratio (parts by weight)

[0067]

[0068] Table 3 Performance test results of the embodiment

[0069]

[0070] Table 4 Performance test results of comparative examples

[0071]

[0072] The comparative examples are all the same as the single variable in Example 1. Comparative Example 1 does not add the wear-resistant masterbatch, Comparative Example 2 uses linear SBS, Comparative Example 3 adds too much wear-resistant masterbatch, Comparative Example 4 does not add SBS, Comparative Example 5 adds polytetrafluoroethylene alone, low-density polyethylene and silicone to make wear-resistant masterbatch, Comparative Example 6 adds too much SBS, Comparative Example 7 contains too low content of linear low-density polyethylene and polytetrafluoroethylene in the wear-resistant masterbatch, Comparative Example 8 uses high-density polyethylene, and Comparative Example 9 uses low-density polyethylene. None of the above comparative examples can reduce the gloss of the material or the noise generated during friction, while having a lower friction coefficient and wear loss.

[0073] Based on the test data of surface gloss, noise, friction coefficient and wear loss in Tables 3 to 4, the POM composition prepared in the embodiment has a friction coefficient of less than 0.18, a wear loss of less than 0.3 mg, a surface gloss of less than 19, and a noise generated by friction of no more than 70 dB, which has obvious advantages over the comparative example.

[0074] 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 POM composition, characterized in that In parts by weight, it comprises the following components: The wear-resistant masterbatch is a composition of linear low-density polyethylene, polytetrafluoroethylene and silicone; The percentage of each component in the wear-resistant masterbatch is: linear low-density polyethylene 35-55%, polytetrafluoroethylene 10-30%, silicone 35-55%; The styrene-butadiene-styrene block copolymer is a star-shaped polymer.

2. The POM composition according to claim 1, characterized in that The content of styrene in the styrene-butadiene-styrene block copolymer is 30-75%.

3. The POM composition according to claim 1, characterized in that The melt flow rate of the POM resin is 1.5 to 30 g / 10 min, preferably 2.5 to 14 g / 10 min.

4. The POM composition according to claim 1, characterized in that The silicone oil is any one of hydroxy silicone oil, long-chain alkyl silicone oil with a C12 or greater chain, or phenyl silicone oil.

5. The POM composition according to claim 1, characterized in that The weight average molecular weight of the silicone oil is ≤6000, and the weight average molecular weight of the silicone is ≥200000.

6. The POM composition according to claim 1, characterized in that The POM composition further includes a processing aid, and the weight portion of the processing aid is 0 to 1 part.

7. The POM composition according to claim 6, characterized in that The processing aid is one or more of a primary antioxidant, a secondary antioxidant, a formaldehyde absorber, and a weathering agent.

8. The method for preparing the POM composition according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: weighing each component by weight, mixing silicone oil with a styrene-butadiene-styrene block copolymer component, then adding POM resin and wear-resistant masterbatch, mixing in a high-speed mixer, and melt-extruding through a twin-screw extruder, cooling, and granulating to obtain the POM composition.

9. The method for preparing the POM composition according to claim 8, wherein: The melting temperature is 150°C to 200°C.

10. Use of the POM composition according to any one of claims 1 to 7 in the preparation and production of automobiles, home appliances, electronic and electrical products or daily necessities.

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