Fiber-reinforced AS (acrylonitrile-styrene) resin composition as well as preparation method and application thereof

Abstract

The invention discloses a fiber reinforced AS (acrylonitrile-styrene) resin composition, which is prepared from the following components in parts by weight: 80 parts of acrylonitrile / alpha-methyl styrene / styrene copolymer, 10 to 40 parts of glass fiber and 0.5 to 5 parts of compatilizer, wherein the acrylonitrile chain segment accounts for 25-35 wt% of the total weight of the acrylonitrile / alpha-methylstyrene / styrene copolymer, and the alpha-methylstyrene chain segment accounts for 14-32 wt% of the total weight of the acrylonitrile / alpha-methylstyrene / styrene copolymer. Through the acrylonitrile / alpha-methylstyrene / styrene copolymer with specific parameters, the highly oriented defect of fibers in the injection molding process can be effectively improved, the linear combustion rate of HB is further reduced, and the fiber-reinforced AS resin composition has good melt processability.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly to a fiber-reinforced AS resin composition, a preparation method thereof, and an application thereof. Background Art

[0002] AS resin (acrylonitrile - styrene copolymer) is a thermoplastic polymer material with high strength, excellent transparency, and easy processing. The styrene segment makes the AS resin harder and easier to process, and the acrylonitrile segment endows the AS resin with better chemical resistance and heat resistance. AS resin has excellent combustion performance, and its HB combustion performance can meet the standards of UL94-HB grade. The linear burning rate of the 3-mm-thick AS resin is about 30 mm / min.

[0003] Glass fiber reinforcement is an important modification method for AS. The addition of glass fiber can significantly improve the strength and rigidity of the material, reduce its linear thermal expansion coefficient, and endow it with better dimensional stability, making it suitable for parts with higher requirements for strength and dimensional stability, such as air conditioner fan blades, audio housings, and keels of sports floors.

[0004] However, due to the wick effect of glass fiber, the combustion performance of the reinforced AS composition will be significantly reduced (the linear burning rate of the 3-mm-thick reinforced AS material is 41-46 mm / min, and the combustion performance can no longer meet the standards of UL94-HB grade). The so-called wick effect is like a candle that needs a wick to burn. When a candle is lit, due to the existence of the wick, a guiding effect is generated. The melted liquid flows along the wick (highly oriented fiber) to the direction with higher temperature. The top of the wick is closest to the flame and has the highest temperature, which vaporizes the liquid and then burns. The heat generated by the combustion promotes the upward transport of the molten liquid for vaporization combustion, and so on, reducing the flame retardancy of the AS resin. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above technical defects and provide a fiber-reinforced AS resin composition with a low linear burning rate and good melt processability.

[0006] The present invention is realized by the following technical solutions: A fiber-reinforced AS resin composition, by weight, comprises the following components: 80 parts of acrylonitrile / α-methylstyrene / styrene copolymer; 10-40 parts of glass fiber; 0.5-5 parts of compatibilizer; Among them, the acrylonitrile segment accounts for 25-35 wt% of the total weight of the acrylonitrile / α-methylstyrene / styrene copolymer, and the α-methylstyrene segment accounts for 14-32 wt% of the total weight of the acrylonitrile / α-methylstyrene / styrene copolymer.

[0007] Through experiments, it is found that the α-methylstyrene segment has the most significant impact on the melt index of the composition compared to the acrylonitrile segment. When the acrylonitrile content is 25-35 wt%, if the proportion of the α-methylstyrene segment in the acrylonitrile / α-methylstyrene / styrene copolymer is higher, the HB linear burning rate is slower, but the melt fluidity will decrease significantly. In order to obtain a slower HB linear burning rate and good processability, through experiments, it is found that the upper limit of the α-methylstyrene segment in the total weight of the AS resin mixture is 32 wt%. If the acrylonitrile content is too low, the HB linear burning rate will be accelerated, and if the acrylonitrile content is too high, the melt fluidity will be reduced.

[0008] Preferably, the α-methylstyrene segment accounts for 18-28 wt% of the total weight of the acrylonitrile / α-methylstyrene / styrene copolymer.

[0009] More preferably, the α-methylstyrene segment accounts for 21-25 wt% of the total weight of the acrylonitrile / α-methylstyrene / styrene copolymer.

[0010] The content of the α-methylstyrene segment can be characterized by nuclear magnetic C 13 NMR.

[0011] The acrylonitrile / α-methylstyrene / styrene copolymer (abbreviated as α-AS resin in the specific implementation) can be a commercially available product or obtained by self-making. Among them, the self-making method can be: the acrylonitrile / α-methylstyrene / styrene copolymer adopts an emulsion polymerization production process. In a reactor equipped with a stirrer, a thermometer, and a spherical reflux condenser, distilled water, sodium dodecyl sulfate, and the monomer in the ratio are added in sequence, and pre-emulsified for 30 minutes under stirring. When the temperature rises to the set temperature, an initiator is added. After the reaction is completed, the reaction material is cooled to room temperature and discharged, demulsified with a 2% aqueous solution of aluminum sulfate, washed 3-5 times with distilled water, filtered, and vacuum dried to constant weight to obtain the acrylonitrile / α-methylstyrene copolymer.

[0012] The present invention has no special limitation on the melt flow rate of the acrylonitrile / α-methylstyrene / styrene copolymer. Through experiments, it is found that when the melt index is 5-30 g / 10 min, the purpose of the present invention can be achieved, and the test conditions are 220 °C and 10 kg.

[0013] The compatibilizer described above is selected from at least one of ABS-g-MAH, ABS-g-GMA, AS-g-MAH, methyl methacrylate, styrene-maleic anhydride copolymer, and styrene-acrylonitrile-glycidyl methacrylate copolymer.

[0014] Preferably, the compatibilizer is selected from AS-g-MAH.

[0015] 0 - 40 parts of acrylonitrile / styrene copolymer can be added according to the actual situation to adjust the melt flow property or other properties. However, the mixture formed by acrylonitrile / α-methylstyrene / styrene copolymer and acrylonitrile / styrene copolymer needs to meet the following conditions: the acrylonitrile chain segment accounts for 25 - 35 wt% of the total weight of the mixture, and the α-methylstyrene chain segment accounts for 14 - 32 wt% of the total weight of the mixture, preferably 18 - 28 wt%, more preferably 21 - 25 wt%.

[0016] The acrylonitrile / styrene copolymer can be a commercially available product or obtained by self-production. Using a continuous bulk polymerization production process, while continuously adding acrylonitrile and styrene monomers and a molecular weight regulating agent in a set ratio to the reactor, the reaction liquid is continuously discharged from the reactor at the same time. The unreacted monomers and polymers are separated during the devolatilization process. The polymerization product is transported to the extrusion process for pelletizing to become a finished product, and the unreacted monomers are recovered in the recovery process and then all returned to the raw material process for recycling.

[0017] Whether to add 0 - 1 part of lubricant can be selected according to actual needs. The lubricant can be one or several of fatty acid amide, pentaerythritol stearate, solid paraffin, liquid paraffin, stearate, silicone, or N,N'-ethylenebisstearamide.

[0018] The preparation method of the fiber-reinforced AS resin composition of the present invention includes the following steps: mixing each component evenly according to the ratio, and extruding and pelletizing through a twin-screw extruder. The temperature range of the screw is 210 - 250 °C, and the rotation speed is 100 - 500 r / min.

[0019] The application of the fiber-reinforced AS resin composition of the present invention is used for preparing an electrical appliance housing.

[0020] The HB linear burning rate of the fiber-reinforced AS resin composition of the present invention is less than 40 mm / min, and the melt flow rate > 4 g / 10 min (220 °C, 10 kg), preferably ≥ 4.5 g / 10 min (220 °C, 10 kg), more preferably ≥ 5.5 g / 10 min (220 °C, 10 kg).

[0021] The present invention has the following beneficial effects: The present invention uses an acrylonitrile / α-methylstyrene / styrene copolymer with a specific acrylonitrile segment content and α-methylstyrene segment content. Due to the stronger interaction between AS with a high acrylonitrile content and glass fiber, and by selecting a specific compatibilizer system, the interaction between glass fiber and the polymer matrix is further enhanced. Moreover, through a specific content of α-methylstyrene segments, the melt strength of the material is further increased, thereby reducing the orientation of glass fiber along the injection molding flow direction. This can make the distribution of glass fiber in the matrix resin more uniform, and greatly reduce the influence of the orientation of glass fiber on the HB combustion performance of the material. As a result, the HB linear combustion rate of the glass fiber-reinforced AS material decreases significantly, meeting the standard requirements of UL94 for HB combustion, greatly improving the safety of using the reinforced AS material, and having good melt processing performance. Embodiment

[0022] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made. These all belong to the protection scope of the present invention.

[0023] The sources of raw materials used in the present invention are as follows: Acrylonitrile wt% α-Methylstyrene wt% Styrene wt% Melt flow rate g / 10min α-AS resin A 30 14 56 15.2 α-AS resin B 30 18 52 13.7 α-AS resin C 30 21 49 12.2 α-AS resin D 30 25 45 10.7 α-AS resin E 30 28 42 9.2 α-AS resin F 30 32 38 8 α-AS resin G 25 25 50 11.3 α-AS resin H 35 25 40 10.2 α-AS resin I 30 10 60 16.7 α-AS resin J 30 35 35 6.5 α-AS resin K 20 25 55 11.8 α-AS resin L 40 25 35 8.2 AS resin 30 0 70 20.2 The above AS resin is self-made.

[0024] Glass fiber: ECS13-4.5-534A.

[0025] AS-g-MAH: S601N.

[0026] ABS-g-MAH: KT-2H.

[0027] Styrene-acrylonitrile-glycidyl methacrylate copolymer: SAG-002.

[0028] Methyl methacrylate: PMMA CM-207.

[0029] Styrene-maleic anhydride copolymer: SMA 700.

[0030] Preparation method of fiber-reinforced AS resin compositions in examples and comparative examples: According to the ratio, mix each component evenly, and extrude and pelletize through a twin-screw extruder. The screw temperature in zone 1 is 220-250 °C, in zone 2 is 220-240 °C, in zone 3 is 210-220 °C, in zone 4 is 210-230 °C, in zone 5 is 210-230 °C, the die temperature is 220-230 °C, and the rotation speed is 100-500 r / min.

[0031] Test methods for each item: (1) HB linear burning rate: UL 94-2018 HB combustion performance test, the specimen thickness is 3 mm, and the test equipment is the horizontal and vertical combustion tester HVUL2 from ATLAS, USA.

[0032] (2) Melt flow rate: Tested according to the standard ISO 1133-2-2011, using the conditions of 220 °C and 10 kg, and the test equipment is BMF001 from Zwick, Germany.

[0033] Table 1: Component contents (parts by weight) and test results of fiber-reinforced AS resin compositions in Examples 1-10

[0034] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 α-AS resin type A B C D E F α-AS resin content 80 80 80 80 80 80 Glass fiber 20 20 20 20 20 20 AS-g-MAH 3 3 3 3 3 3 HB linear burning rate, (mm / min) 39.3 38.1 37.2 36.3 35.6 34.7 Melt flow rate, g / 10min 8.1 7.2 6.4 5.6 4.8 4.2 As can be seen from Examples 1-8, when the content of the preferred α-methylstyrene segment is used, a better balance between the HB linear burning rate and the melt flow rate can be obtained.

[0035] Continued Table 1: Example 7 Example 8 Example 9 Example 10 α-AS resin type G H A A α-AS resin content 80 80 80 80 Glass fiber 20 20 10 40 AS-g-MAH 3 3 0.5 5 HB linear burning rate, (mm / min) 36.7 35.9 38.5 39.9 Melt flow rate, g / 10min 5.9 5.5 10.7 5.2 Table 2: Component contents (parts by weight) and test results of fiber-reinforced AS resin compositions in Examples 11-14 Example 11 Example 12 Example 13 Example 14 α-AS resin A 80 80 80 80 Glass fiber 20 20 20 20 AS-g-MAH ABS-g-MAH 3 SAG-002 3 CM-207 3 PMMA SMA 700 3 HB linear burning rate, (mm / min) 39.4 39.5 39.7 39.6 Melt flow rate, g / 10min 8.2 8.1 8.3 8.2 As can be seen from Examples 1 / 11-14, when the compatibilizer is preferably AS-g-MAH, the HB linear burning rate is lower.

[0036] Table 2: Component contents (parts by weight) and test results of fiber-reinforced AS resin compositions in Examples 15-18 Example 15 Example 16 Example 17 Example 18 α-AS resin type B C E F α-AS resin content 80 80 80 80 Glass fiber 20 20 20 20 AS-g-MAH 3 3 3 3 AS resin 10 20 30 40 α-Methylstyrene content, wt% 16 16.8 20.4 21.3 HB linear burning rate, (mm / min) 38.9 38.4 37.4 36.7 Melt flow rate, g / 10min 7.7 7.1 6.8 6.2 As can be seen from Examples 2 / 3 / 5 / 6 and Examples 15-18, when AS resin is added, when the acrylonitrile segment accounts for 25-35 wt% of the total weight of the mixture and the α-methylstyrene segment accounts for 14-32 wt% of the total weight of the mixture, a slow HB linear burning rate can be maintained while the melt flow rate is increased; when the content of the α-methylstyrene segment is preferred, the HB linear burning rate is also slower.

[0037] Table 4: Component contents (parts by weight) and test results of fiber-reinforced AS resin compositions in Comparative Examples Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 α-AS resin type I J K L α-AS resin content 80 80 80 80 AS resin 80 Glass fiber 20 20 20 20 20 AS-g-MAH 3 3 3 3 3 HB linear burning rate, (mm / min) 42.2 34.1 41.9 35.2 43.3 Melt flow rate, g / 10min 9.1 3.5 6.5 3.8 11.2 As can be seen from Comparative Examples 1 / 2, when the content of α-methylstyrene is too low, the HB linear burning rate is too high; when the content of α-methylstyrene is too high, the melt flow rate is low and it is difficult to be industrially applied.

[0038] As can be seen from Comparative Example 3, when the acrylonitrile content is too low, the HB linear burning rate is too high.

[0039] As can be seen from Comparative Example 4, when the acrylonitrile content is too high, the melt flow rate is low, making it difficult for industrial applications.

[0040] As can be seen from Comparative Example 5, the linear burning rate of ordinary AS resin HB is too high.

Claims

1. A fiber-reinforced AS resin composition, characterized in that, by weight, it comprises the following components: acrylonitrile / α-methylstyrene / styrene copolymer 80 parts; glass fiber 10 - 40 parts; compatibilizer 0.5 - 5 parts; wherein, the acrylonitrile segment accounts for 25 - 35 wt% of the total weight of the acrylonitrile / α-methylstyrene / styrene copolymer, and the α-methylstyrene segment accounts for 14 - 32 wt% of the total weight of the acrylonitrile / α-methylstyrene / styrene copolymer.

2. The fiber-reinforced AS resin composition according to claim 1, characterized in that, the α-methylstyrene segment accounts for 18 - 28 wt% of the total weight of the acrylonitrile / α-methylstyrene / styrene copolymer.

3. The fiber-reinforced AS resin composition according to claim 2, characterized in that, the α-methylstyrene segment accounts for 21 - 25 wt% of the total weight of the acrylonitrile / α-methylstyrene / styrene copolymer.

4. The fiber-reinforced AS resin composition according to claim 1, characterized in that, the melt flow rate of the acrylonitrile / α-methylstyrene / styrene copolymer is 5 - 30 g / 10 min, and the test conditions are 220 °C and 10 kg.

5. The fiber-reinforced AS resin composition according to claim 1, characterized in that, the compatibilizer is selected from at least one of ABS-g-MAH, ABS-g-GMA, AS-g-MAH, methyl methacrylate, styrene-maleic anhydride copolymer, and styrene-acrylonitrile-glycidyl methacrylate copolymer.

6. The fiber-reinforced AS resin composition according to claim 5, characterized in that, the compatibilizer is selected from AS-g-MAH.

7. The fiber-reinforced AS resin composition according to claim 1, characterized in that, by weight, it further comprises 0 - 40 parts of acrylonitrile / styrene copolymer, and it satisfies that in the mixture formed by the acrylonitrile / α-methylstyrene / styrene copolymer and the acrylonitrile / styrene copolymer, the acrylonitrile segment accounts for 25 - 35 wt% of the total weight of the mixture, and the α-methylstyrene segment accounts for 14 - 32 wt% of the total weight of the mixture, preferably 18 - 28 wt%, more preferably 21 - 25 wt%.

8. The fiber-reinforced AS resin composition according to claim 1, characterized in that, by weight, it further comprises 0 - 1 part of lubricant.

9. The preparation method of the fiber-reinforced AS resin composition according to any one of claims 1 - 8, characterized in that, it comprises the following steps: according to the ratio, mix each component evenly, and extrude and pelletize through a twin-screw extruder, the screw temperature range is 210 - 250 °C, and the rotation speed is 100 - 500 r / min.

10. The application of the fiber-reinforced AS resin composition according to any one of claims 1 - 8, characterized in that, it is used for preparing electrical appliance housings.