阅读说明：本技术 一种低线性膨胀系数聚丙烯复合材料及其制备方法 (Polypropylene composite material with low linear expansion coefficient and preparation method thereof ) 是由 张丰 杨杰 高翔 李德燊 王伟 申应军 于 2021-09-26 设计创作，主要内容包括：本发明涉及高分子材料技术领域,特别涉及一种低线性膨胀系数聚丙烯复合材料及其制备方法。该聚丙烯复合材料的原料组分包括聚丙烯树脂、增韧剂以及其他助剂；所述增韧剂包括乙烯-辛烯共聚物、聚苯乙烯-b-聚(乙烯/乙烯/丙烯)-b-聚苯乙烯以及热塑性聚酯弹性体；按重量计,所述聚丙烯树脂、乙烯-辛烯共聚物、聚苯乙烯-b-聚(乙烯/乙烯/丙烯)-b-聚苯乙烯、热塑性聚酯弹性体的比值为(50～60):(5～15):(3～10):(3～10)。本发明提供的聚丙烯复合材料在高温区仍具有低线性膨胀系数性能,同时,所得聚丙烯聚合材料具有良好的冲击性能和较高刚性,综合力学性能良好。(The invention relates to the technical field of high polymer materials, in particular to a polypropylene composite material with a low linear expansion coefficient and a preparation method thereof. The polypropylene composite material comprises the raw material components of polypropylene resin, a toughening agent and other auxiliary agents; the toughening agent comprises an ethylene-octene copolymer, polystyrene-b-poly (ethylene/propylene) -b-polystyrene, and a thermoplastic polyester elastomer; the ratio of the polypropylene resin, the ethylene-octene copolymer, the polystyrene-b-poly (ethylene/propylene) -b-polystyrene and the thermoplastic polyester elastomer is (50-60) to (5-15) to (3-10) by weight. The polypropylene composite material provided by the invention still has low linear expansion coefficient performance in a high-temperature area, and meanwhile, the obtained polypropylene polymer material has good impact property, higher rigidity and good comprehensive mechanical property.)

1. The polypropylene composite material with the low linear expansion coefficient is characterized in that the raw material components comprise polypropylene resin, a toughening agent and other auxiliary agents;

the toughening agent comprises an ethylene-octene copolymer, polystyrene-b-poly (ethylene/propylene) -b-polystyrene, and a thermoplastic polyester elastomer;

the ratio of the polypropylene resin, the ethylene-octene copolymer, the polystyrene-b-poly (ethylene/propylene) -b-polystyrene and the thermoplastic polyester elastomer is (50-60) to (5-15) to (3-10) by weight.

2. The low coefficient of linear expansion polypropylene composite of claim 1 wherein the other additives comprise a filler;

the filler is talcum powder; the ratio of the polypropylene resin, the ethylene-octene copolymer, the polystyrene-b-poly (ethylene/propylene) -b-polystyrene, the thermoplastic polyester elastomer and the filler is (50-60): (5-15), (3-10) and (20-40).

3. The low coefficient of linear expansion polypropylene composite of claim 2, wherein the other additives comprise an antioxidant and a lubricant;

the high-performance polypropylene composite material comprises, by weight, 50-60 parts of polypropylene resin, 5-15 parts of ethylene-octene copolymer, 3-10 parts of polystyrene-b-poly (ethylene/propylene) -b-polystyrene, 3-10 parts of thermoplastic polyester elastomer, 20-40 parts of filler, 0.3-0.6 part of antioxidant and 0.2-0.3 part of lubricant.

4. The low linear expansion coefficient polypropylene composite according to claim 1, wherein the polypropylene resin is one or more of block co-polypropylene and random co-polypropylene.

5. The polypropylene composite material with a low linear expansion coefficient as claimed in claim 4, wherein the melt flow rate of the polypropylene resin is (10-100) g/10 min.

6. The polypropylene composite material with low linear expansion coefficient according to claim 3, wherein the antioxidant is one or more of the group consisting of antioxidant 1010, antioxidant 168, antioxidant 1076, and antioxidant 1790.

7. The polypropylene composite of claim 3, wherein the lubricant is one or more of PE wax, EBS, stearate type lubricant.

8. The polypropylene composite material with low linear expansion coefficient as claimed in claim 7, wherein the stearate lubricant is one or more of zinc stearate, calcium stearate and stearic acid amide.

9. A method for preparing a low coefficient of linear expansion polypropylene composite according to any one of claims 1 to 8, comprising the steps of:

s100, weighing polypropylene resin, a toughening agent, a filler, an antioxidant and a lubricant according to a certain weight, and mixing to obtain a mixture M;

and S200, adding the mixture M into a double-screw extruder through a feeder, and performing melt extrusion granulation in the double-screw extruder to obtain the low-linear expansion coefficient polypropylene composite material.

10. The preparation method of the polypropylene composite material with the low linear expansion coefficient as claimed in claim 9, wherein the length-diameter ratio of a screw of the twin-screw extruder is (40-56): 1, the rotation speed of the screw is 400-700 rpm, and the melt extrusion temperature is 200-230 ℃.

Technical Field

The invention relates to the technical field of high polymer materials, in particular to a polypropylene composite material with a low linear expansion coefficient and a preparation method thereof.

Background

The polypropylene has been widely used for automobile interior and exterior trim because of its excellent comprehensive properties, wide sources, light weight, low price, easy molding and processing, etc. In automobile exterior parts products, such as automobile bumpers, skirtboards, fenders and other products, the products need to be in a cold and hot alternating state for a long time, and the change of the material dimension is large, so that assembly gaps or deformation is generated, and therefore, the material applied to the automobile exterior parts and other products is required to have a low linear expansion coefficient.

At present, in the prior art, the shrinkage rate of the material is reduced mainly by adding the POE toughening agent, increasing the proportion of the talcum powder and the like, and the requirement of low linear expansion is met, but the impact performance of the material is greatly influenced by the use amount of the talcum powder, and the rigidity of the material with higher cost is reduced by increasing the use amount of the POE toughening agent. In the prior art, the shrinkage rate and the linear expansion coefficient of the material are reduced by adding glass fiber and whisker, but the product deformation and the like are caused.

The Chinese patent application with the application number of CN201210574740.7 and the publication date of 2013, 04 and 17 discloses a glass fiber reinforced polypropylene composite material for an automobile radiator grille and a preparation process thereof, and the glass fiber reinforced polypropylene composite material comprises the following components in parts by weight: 32-78 wt% of polypropylene; 0-2 wt% of heat stabilizer; 0-2 wt% of an auxiliary agent; 0-2 wt% of light stabilizer; 0-2 wt% of nucleating agent; 5-20 wt% of a toughening agent; 2-10 wt% of compatilizer; 15-30 wt% of chopped glass fiber. Due to the fact that the chopped glass fibers are used for filling, rigidity and heat resistance of the material are greatly improved, meanwhile, the chopped glass fibers can also reduce the linear expansion Coefficient (CLTE) of the material, and the problems of size change and deformation of a workpiece caused by rapid change of external environment temperature are solved. However, the chopped glass fiber is adopted to reduce the linear expansion coefficient of the polypropylene composite material, and the use amount of the glass fiber is large, so that the problems of fiber floating in appearance and warping of a product are caused.

The Chinese patent application with the application number of CN201511019839.0 and the publication date of 2016, 04, month and 20 discloses a low-linear expansion coefficient polypropylene composite material capable of realizing light weight and a preparation method thereof. The polypropylene composite material comprises the following raw materials in percentage by weight: 68-86% of polypropylene, 5-15% of whisker, 6-10% of toughening agent, 0.5-2% of high-efficiency nucleating agent, 1-3% of compatilizer, 0.1-1% of antioxidant and 0.1-2% of other additives. The invention can ensure that the linear expansion coefficient of the polypropylene material is effectively reduced under the condition of lower density of the composite material by adding the efficient nucleating agent and a small amount of whiskers, and simultaneously endows the material with the characteristic of isotropy. However, the whisker is adopted to reduce the linear expansion coefficient of the material, the length diameter of the whisker is large, so that the difference of the shrinkage rate of the material in the flowing direction and the vertical flowing direction is large, and the size, the warping and the like of the product are influenced.

The traditional polypropylene material for the automobile generally adopts ethylene/octene copolymer (POE) elastomer as a toughening agent to improve the normal temperature and low temperature toughness of the material, and because the glass transition temperature of the POE is very low (about 50 ℃), the POE elastomer can play a good role in reducing the linear expansion coefficient in a low temperature range (about (-30 ℃ -23 ℃) of the linear expansion coefficient test standard, but because the heat-resistant temperature of the POE elastomer is insufficient and the melting point is only about 40 ℃, the linear expansion coefficient of the ethylene/octene copolymer (POE) modified polypropylene material in a high temperature range (23 ℃ -85 ℃) is very high, and the use requirement of automobile exterior parts cannot be met.

Disclosure of Invention

In order to overcome the defects of the prior art mentioned in the background art, the invention provides a low-linear-expansion-coefficient polypropylene composite material, which comprises the following raw material components of polypropylene resin, a toughening agent and other auxiliary agents;

the toughening agent comprises an ethylene-octene copolymer, polystyrene-b-poly (ethylene/propylene) -b-polystyrene, and a thermoplastic polyester elastomer; the ratio of the polypropylene resin, the ethylene-octene copolymer, the polystyrene-b-poly (ethylene/propylene) -b-polystyrene and the thermoplastic polyester elastomer is (50-60) to (5-15) to (3-10) by weight.

In one embodiment, the other additives include fillers; the filler is talcum powder; the ratio of the polypropylene resin, the ethylene-octene copolymer, the polystyrene-b-poly (ethylene/propylene) -b-polystyrene, the thermoplastic polyester elastomer and the filler is (50-60): (5-15), (3-10) and (20-40).

In one embodiment, the other additives include antioxidants and lubricants; the high-performance polypropylene composite material comprises, by weight, 50-60 parts of polypropylene resin, 5-15 parts of ethylene-octene copolymer, 3-10 parts of polystyrene-b-poly (ethylene/propylene) -b-polystyrene, 3-10 parts of thermoplastic polyester elastomer, 20-40 parts of filler, 0.3-0.6 part of antioxidant and 0.2-0.3 part of lubricant.

In one embodiment, the polypropylene resin is one or more of block copolymer polypropylene and random copolymer polypropylene.

In one embodiment, the melt flow rate of the polypropylene resin is (10-100) g/10 min.

In one embodiment, the antioxidant is one or more of the group consisting of antioxidant 1010, antioxidant 168, antioxidant 1076, and antioxidant 1790.

In one embodiment, the lubricant is one or more combinations of PE wax, EBS, stearate-based lubricants.

In one embodiment, the stearate-based lubricant is one or more of zinc stearate, calcium stearate, and stearic acid amide.

The invention also provides a preparation method of the polypropylene composite material with the low linear expansion coefficient, which comprises the following steps:

s100, weighing polypropylene resin, a toughening agent, a filler, an antioxidant and a lubricant according to a certain weight, and mixing to obtain a mixture M;

and S200, adding the mixture M into a double-screw extruder through a feeder, and performing melt extrusion granulation in the double-screw extruder to obtain the low-linear expansion coefficient polypropylene composite material.

In one embodiment, the double-screw extruder has a screw length-diameter ratio of (40-56): 1, a screw rotation speed of 400-700 rpm, and a melt extrusion temperature of 200-230 ℃.

Compared with the prior art, the polypropylene composite material with the low linear expansion coefficient provided by the invention has the following technical effects:

the polypropylene composite material provided by the invention still has low linear expansion coefficient performance in a high-temperature area, and meanwhile, the obtained polypropylene polymer material has good impact property, higher rigidity and good comprehensive mechanical property; the temperature change of the finished piece made of the polypropylene composite material has little influence on the size, and the polypropylene composite material is suitable for preparing automobile finished pieces such as automobile bumpers, skirtboards, fenders and the like.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the following description will clearly and completely describe the embodiments of the present invention, and obviously, the described embodiments are a part of the embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention also provides a preparation method of the polypropylene composite material with the low linear expansion coefficient, which comprises the following steps:

(1) weighing the polypropylene resin, the toughening agent, the filler, the antioxidant and the lubricant according to a certain weight, putting into a high-speed mixer, mixing for 2min, and uniformly mixing the materials to obtain a mixture M;

(2) adding the mixture M into a double-screw extruder through a feeder, and performing melt blending extrusion, cooling and grain cutting in the double-screw extruder to obtain the low-linear expansion coefficient polypropylene composite material granules, and drying the granules for later use; wherein the length-diameter ratio of the screw of the double-screw extruder is (40-56): 1, the rotating speed of the screw is (400-700) rpm, and the melt extrusion temperature is 200-230 ℃.

The present invention also provides the formulations (unit: parts by weight) of the examples and comparative examples shown in Table 1:

TABLE 1

The raw material components in the examples and comparative examples in table 1 are selected in the same way, and the components are specifically as follows:

the polypropylene is PP with the brand number BX3800 produced by SK company, the PP is block copolymerization polypropylene, and the melt flow rate of the PP is 30g/10min (230 ℃,2.16 kg). The ethylene-octene copolymer (also called POE) is POE of DOW company brand ENGAGE 8200; the density of the product is 0.870g/g/cm³(ii) a The polystyrene-b-poly (ethylene/propylene) -b-polystyrene (also called SEEPS) is SEEPS with the brand SEPTON 4055 produced by Kuraray company; its styrene content is 30%; the thermoplastic polyester elastomer (also called TPEE) is selected from the TPEE with the brand name SC988 produced by Dupont company; the Shore hardness D of the coating is 82 degrees; the talcum powder is produced by Imifabi corporation under the trade name HTP Ultra 05L; the particle size D50 is 0.65 μm; the antioxidant is prepared from antioxidant 1010 and antioxidant 168 according to a mass ratio of 2: 1 is compounded; the lubricant is zinc stearate of China Huaming Tai chemical industry Co., Ltd under the brand number BS-2818;

it should be noted that:

in addition to the practical choices embodied in the above embodiments, the polypropylene resin may preferably be one or a combination of block copolymer polypropylene and random copolymer polypropylene, and the melt flow rate thereof may be in the range of 10 to 100g/10min (230 ℃,2.16kg), including but not limited to the practical choices embodied in the above embodiments;

in addition to the actual choices presented in the above specific embodiments, preferably, the antioxidant may be one or more of antioxidant 1010, antioxidant 168, antioxidant 1076, and antioxidant 1790; the combination of antioxidant 168 and antioxidant 1010 used in the examples is preferred.

In addition to the practical options presented in the above embodiments, preferably, the lubricant may be one or more combinations of PE wax, EBS, stearate-based lubricants, such as zinc stearate, calcium stearate, or stearic acid amide, and includes but is not limited to the practical options presented in the above embodiments;

in addition to the actual selection embodied by the above specific embodiment, the mass ratio of POE, SEEPS and TPEE is (5-15): (3-10): (3-10) any range; preferably, the mass ratio of POE, SEEPS and TPEE is (5-9): (3-5): (3-5); furthermore, the mass ratio of POE, SEEPS and TPEE is 1:1:1 as the preferred proportion;

according to the formulation of table 1, the polypropylene composites were prepared by using the raw material components of the examples and comparative examples according to the following preparation method:

(1) weighing the polypropylene resin, the toughening agent, the filler, the antioxidant and the lubricant according to a certain weight, putting into a high-speed mixer, mixing for 2min, and uniformly mixing the materials to obtain a mixture M;

(2) adding the mixture M into a double-screw extruder through a feeder, and performing melt blending extrusion, cooling and grain cutting in the double-screw extruder to obtain the low-linear expansion coefficient polypropylene composite material granules, and drying the granules for later use; wherein the temperature of each zone of the double-screw extruder is 150 ℃, 210 ℃, 200 ℃ of the head temperature, 48:1 of the length-diameter ratio of the screw of the double-screw extruder and 600rpm from 1 to 10 in sequence.

The polypropylene materials prepared in the examples and comparative examples were tested for the related performance indexes under the same test conditions, and the test results are shown in the following table 2:

TABLE 2

The impact strength test standard of the simply supported beam is ISO179-1, and the size of a test sample is 80mm multiplied by 10mm multiplied by 4mm (if a gap exists, the gap is reserved with the width of 8 mm); the notched Izod impact strength test standard is ISO179, and the specimen size is 80mm × 10mm × 4mm (notch retention width 8 mm); the test standard of the tensile strength IS IS0527-2, the sample size IS 1A type (gauge length IS 115mm, parallel part IS 10mm multiplied by 4mm), and the tensile speed IS 50 mm/min; the bending strength test standard is ISO178, the sample size is 80mm multiplied by 10mm multiplied by 4mm (length multiplied by width multiplied by height), the bending speed is 2 mm/min; the linear expansion coefficient in the flow direction is measured according to the standard ISO11359-2, and the measurement temperature is-30 ℃ to 85 ℃.

As can be seen from the comparison of the examples and comparative examples:

comparative example 1 compared to example 1, differing only in that TPEE in example 1 was replaced with POE, i.e. the toughener used only POE and SEEPS, the results show that the linear expansion coefficient of the material prepared in comparative example 1 is significantly increased;

comparative example 2 compared with example 1, differing only in that the SEEPS in example 1 was replaced with POE, i.e., the toughener used only POE and TPEE, the results show that the material prepared in comparative example 2 has an increased linear expansion coefficient, deteriorated tensile and flexural properties, and decreased rigidity;

compared with the example 1, the comparative example 3 is only different from the example 1 in that the SEEPS and the TPEE in the examples are replaced by POE, namely, only POE is used as the toughening agent, and the result shows that the linear expansion coefficient of the material prepared by the comparative example 3 is obviously increased, the tensile property and the bending property are poor, and the rigidity is reduced;

compared with the example 1, the difference of the comparative example 4 is that POE, SEEPS and TPEE in the example are all replaced by PP, namely a PP material is used alone, and the result shows that the material prepared in the comparative example 4 has high linear expansion coefficient, lower impact property and poor toughness;

comparative example 5 compared with example 1, differing only in that both POE and SEEPS in the examples are replaced by TPEE, i.e. only TPEE is used as the toughening agent, the result shows that the linear expansion coefficient of the material prepared in comparative example 5 is kept at a low level, but the impact property is reduced and the toughness is deteriorated;

comparative example 6 compared with example 1, differing only in that both POE and TPEE in the examples are replaced by SEEPS, i.e. only SEEPS are used as the toughening agent, the result shows that the linear expansion coefficient of the material prepared in comparative example 6 is kept at a low level, but the impact property is remarkably reduced and the toughness is poor;

compared with the example 1, the difference of the comparative example 7 is that the proportions of POE, TPEE and SEEPS are different, and the proportion of POE among the POE, the TPEE and the SEEPS is reduced, so that the result shows that the linear expansion coefficient of the material prepared by the comparative example 7 is kept at a lower level, but the linear expansion coefficient of the material is slightly increased compared with the example 1, the impact property of the material is obviously reduced, and the toughness of the material is poor;

comparative example 8 is different from example 2 in that the amount of POE used is increased and the ratio of POE to POE is increased, and the results show that the linear expansion coefficient of the material prepared in comparative example 8 is kept low, but the tensile and flexural properties are deteriorated and the rigidity is lowered.

Compared with the method of only adding one or two of POE, SEEPS and TPEE, the method of the invention has better technical effect of adding three materials of POE, SEEPS and TPEE: the prepared polypropylene composite material is subjected to synergistic toughening by POE, SEEPS and TPEE, so that the linear expansion coefficient can be obviously reduced, the problem that the linear expansion coefficient of the existing modified polypropylene material adopting POE as a toughening agent is high in a high-temperature area is solved, the polypropylene composite material still has the effect of low linear expansion coefficient in a high-temperature area, the use requirements of automobile exterior parts can be met, and meanwhile, the polypropylene composite material keeps good impact property and higher rigidity and has good comprehensive mechanical property. In addition, the POE, the SEEPS and the TPEE are added according to a certain mass ratio, when the POE ratio is higher than the range defined by the invention, the rigidity of the material is reduced, and when the POE ratio is lower than the range defined by the invention, the linear expansion coefficient of the material is increased, and the toughness of the material is deteriorated, namely the impact resistance is deteriorated. In conclusion, the polypropylene composite material prepared by the invention adopts POE, SEEPS and TPEE with a certain proportion for synergistic toughening, can obtain the polypropylene composite with low linear expansion coefficient within the temperature range of-30 ℃ to 85 ℃, and can still keep good toughness and rigidity.

In addition, in the existing polypropylene material for reducing the linear expansion coefficient of the material by adding the glass fiber and the whisker, because the length-diameter ratio of the glass fiber, the whisker and other substances is large, the difference of the shrinkage rates of the material in the flowing direction and the vertical flowing direction is large, the size of the product is influenced, and the product is warped and the like; the invention does not add components with large diameter ratio such as glass fiber and whisker, the added filler is micron-sized granular talcum powder particles, and the linear expansion coefficient is reduced through the compound synergistic effect of POE, SEEPS and TPEE, so that the product cannot deform and warp while the linear expansion coefficient of the product is reduced, and the problem of product warping caused by adding the glass fiber, the whisker and other substances is solved. Likewise, the material prepared by the invention does not have the problem of fiber floating caused by excessive increase of glass fiber.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.