Polypropylene composition and preparation method thereof

Abstract

The invention relates to the field of high polymer materials, and discloses a polypropylene composition which is characterized by comprising the following components in parts by weight: 100 parts of polypropylene, 2-10 parts of SEBS-g-DM (Styrene Ethylene Butylene Styrene-g-DM) and 2-10 parts of whisker Si, wherein the SEBS-g-DM is a hydrogenated styrene-butadiene block copolymer elastomer grafted by diethyl maleate, and the SEBS-g-DM is a hydrogenated styrene-butadiene block copolymer elastomer grafted by diethyl maleate. The SEBS-g-DM is adopted to promote polypropylene grain refinement and promote crystal whiskers Si to be dispersed more uniformly in a polypropylene matrix, so that the toughness of polypropylene is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high molecular materials, in particular to a polypropylene composition and a preparation method thereof. BACKGROUND

[0002] Polypropylene is a kind of excellent thermoplastic synthetic resin, which is colorless and translucent, and is a kind of light-weight general-purpose plastic with properties of chemical resistance, heat resistance, electrical insulation, high-strength mechanical properties and good high-wear processing performance, and is widely used in the production of clothing, blanket and other fiber products, medical devices, automobiles, bicycles, parts, conveying pipelines, chemical containers and the like, and is also used for food and drug packaging.

[0003] Polypropylene has extremely wide application in industry and life, but the toughness of polypropylene itself is poor, and it often needs to be toughened and modified to be applied. At present, polypropylene is often added with a toughening agent to improve toughness, but the toughening agent can cause serious loss of tensile strength of polypropylene, so that the strength and toughness cannot be considered at the same time, and are limited in some applications. In order to supplement the tensile strength of polypropylene, a reinforcing agent is often added, and the compatibility of the reinforcing agent with the polypropylene matrix is poor, and a compatibilizer needs to be additionally added to improve the compatibility of the reinforcing agent with the polypropylene matrix. At present, when the reinforcing agent is SEBS, since the SEBS molecular chain does not contain a polar group, it has poor toughening effect on plastics with strong polarity, and it is difficult to achieve the desired effect. SUMMARY

[0004] The present application aims to overcome the problems existing in the prior art, and provides a polypropylene composition and a preparation method thereof.

[0005] In order to achieve the above-mentioned purpose, the first aspect of the present application provides a polypropylene composition, characterized in that the composition comprises: the content of SEBS-g-DM is 2-10 parts by weight, and the content of whisker Si is 2-10 parts by weight, relative to 100 parts by weight of polypropylene; wherein,

[0006] The SEBS-g-DM is a hydrogenated styrene-butadiene block copolymer elastomer grafted with maleic acid diethyl ester.

[0007] The second aspect of the present application provides a preparation method of a polypropylene composition, comprising the following steps:

[0008] (1) drying and uniformly mixing polypropylene, SEBS-g-DM and whisker Si to obtain a premix;

[0009] (2) extruding and granulating the premix;

[0010] The SEBS-g-DM is a hydrogenated styrene-butadiene block copolymer elastomer grafted with maleic acid diethyl ester.

[0011] By the technical scheme, the application can obtain the following beneficial effects:

[0012] (1) The SEBS-g-DM is used to promote the grain refinement of the polypropylene and improve the toughness of the polypropylene.

[0013] (2) The SEBS-g-DM is used to promote the dispersion of the whisker Si in the polypropylene matrix, and further improve the toughness of the polypropylene.

[0014] (3) The whisker Si is used to promote the continuous increase of the crystallinity of the polypropylene, and improve the tensile strength of the polypropylene. DETAILED DESCRIPTION

[0015] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges and any values are understood to be approximate values. The exact numerical values of the endpoints of the ranges and the separate numerical values are not to be construed as limiting, but rather as approximations. For ranges, the endpoints are provided as a separate point for use in the claims.

[0016] The specific embodiments of the application will be described in detail below. It should be understood that the specific embodiments described herein are merely illustrative and are not to be taken in a limiting sense.

[0017] The first aspect of the application provides a polypropylene composition, characterized in that the composition comprises: the content of SEBS-g-DM is 2-10 parts by weight, and the content of whisker Si is 2-10 parts by weight, relative to 100 parts by weight of polypropylene; wherein,

[0018] The SEBS-g-DM is a hydrogenated styrene-butadiene block copolymer elastomer grafted with maleic acid diethyl ester.

[0019] In the application, preferably, the mass ratio of the polypropylene to the SEBS-g-DM is 100:6-8.

[0020] In the application, preferably, the mass ratio of the polypropylene to the whisker Si is 100:5-7.

[0021] In the application, the whisker Si can be the commonly used whisker Si in the art, preferably, the average particle size of the whisker Si is 4-45 μm, and the true density is 2.4-2.65 g / cm 3 .

[0022] In the application, the weight average molecular weight of the SEBS-g-DM is 80,000-150,000.

[0023] In the present application, the structural units provided by hydrogenated styrene in the SEBS-g-DM account for 28-33% of the total weight of the SEBS-g-DM.

[0024] In the present application, the grafting rate of the SEBS-g-DM can be 2.3-4.5 wt%.

[0025] In the present application, the preparation method of the SEBS-g-DM can be mixing and reacting hydrogenated styrene-butadiene, diethyl maleate and dicumyl peroxide.

[0026] In the preferred embodiment of the present application, the preparation method of the SEBS-g-DM can further include drying the hydrogenated styrene-butadiene, diethyl maleate and dicumyl peroxide in a vacuum drying box before mixing and reacting.

[0027] In the preferred embodiment of the present application, the preparation method of the SEBS-g-DM can further include extruding and granulating: extruding and granulating the premix to obtain granules.

[0028] In the preferred embodiment of the present application, in the preparation method of the SEBS-g-DM, the mixing of the hydrogenated styrene-butadiene, diethyl maleate and dicumyl peroxide can be performed in an extrusion process, for example, the hydrogenated styrene-butadiene, diethyl maleate and dicumyl peroxide are reacted in a screw extruder.

[0029] In the preferred embodiment of the present application, the temperature of the screw extruder is 190-225℃; and the rotation speed of the screw extruder can be 60-85 rpm.

[0030] In the preferred embodiment of the present application, the preparation method of the SEBS-g-DM can further include purification: weighing the above granules, contacting and heating the weighed granules with xylene to reflux, mixing and cooling with acetone, mixing with methanol and then filtering to obtain precipitate, and drying the precipitate to obtain the graft of hydrogenated styrene-butadiene and diethyl maleate.

[0031] In the preferred embodiment of the present application, in the purification step, the amount of xylene can be 65-100 mL, preferably 75-85 mL, relative to 40 g of granules.

[0032] In the preferred embodiment of the present application, in the purification step, the amount of acetone can be 65-100 mL, preferably 75-85 mL, relative to 40 g of granules.

[0033] In the preferred embodiment of the present application, in the purification step, the amount of methyl alcohol is not particularly limited as long as it can remove impurities.

[0034] In the preferred embodiment of the present application, in the purification step, the heating reflux temperature is 115-135℃, preferably 120-130℃; the heating reflux time is 1.6-2.4h, preferably 1.8-2.2h.

[0035] In the preferred embodiment of the present application, in the purification step, the cooling temperature after mixing with acetone is 25-35℃, more preferably 28-32℃; the cooling time is 25-35min, more preferably 28-32min.

[0036] In the present application, the mass ratio of the hydrogenated styrene-butadiene and the maleic acid diethyl ester can be 100:9-11, preferably 100:9.5-10.5.

[0037] In the present application, the mass ratio of the hydrogenated styrene-butadiene and the dicumyl peroxide is 100:1-1.4, preferably 100:1.1-1.3.

[0038] In the present application, the reaction temperature can be 190-225℃, and the reaction time can be 10-25min.

[0039] Preferably, the reaction temperature is 210-223℃, and the reaction time is 15-20min.

[0040] The second aspect of the present application provides a preparation method of a polypropylene composition, which comprises the following steps:

[0041] (1) drying and uniformly mixing the polypropylene, SEBS-g-DM and whisker Si to obtain a premix;

[0042] (2) extruding and granulating the premix;

[0043] The SEBS-g-DM is a maleic acid diethyl ester grafted hydrogenated styrene-butadiene block copolymer elastomer.

[0044] In the present application, the extrusion temperature is 220-250℃, and the extrusion time is 10-25min; preferably, the extrusion temperature is 230-250℃, and the extrusion time is 15-20min.

[0045] In the preferred embodiment of the present application, the extrusion can be performed by using a screw extruder, and the rotation speed of the screw extruder is 95-105rmp.

[0046] In the preferred embodiment of the present application, the granules after extrusion and granulation can be dried in a vacuum drying box.

[0047] In the preferred embodiment of the present application, the sample bar for testing can be prepared by using an injection molding machine, and the temperature of the injection molding machine can be 260-270°C.

[0048] In the present application, the weight average molecular weight of the polypropylene can be 80-150 thousand.

[0049] The present application will be described in detail below by way of examples. In the following examples and comparative examples, the specific conditions not specified are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are not specified by the manufacturer, and are all conventional products that can be obtained by market purchase.

[0050] The polypropylene raw material is a commercially available product of BE961MO from Nordic Chemical, and the weight average molecular weight is 100 thousand.

[0051] The hydrogenated styrene-butadiene raw material is a commercially available product of G1654 from Cognis, and the proportion of hydrogenated styrene is 31wt%.

[0052] The diethyl maleate is a commercially available product with CAS No. 141-05-9 and an effective content of ≥99%.

[0053] The dicumyl peroxide is a commercially available product with CAS No. 80-43-3 and an effective content of ≥98%.

[0054] The whisker Si is a commercially available product of 1250 from Shanghai Huijingyanao Nanometer New Material Co., Ltd.

[0055] Example 1

[0056] (I) Preparation of SEBS-g-DM

[0057] (1) Dry premixing: 100g of hydrogenated styrene-butadiene, 10g of diethyl maleate and 1.4g of dicumyl peroxide were placed in a vacuum drying oven and mixed uniformly after drying to obtain a premix;

[0058] (2) Extrusion: the premix was extruded by a double screw extruder with a screw speed of 80r / min, and the temperature of the double screw extruder was 220°C to obtain a strand;

[0059] (3) Granulation and drying: the strand obtained in step (2) was cooled with water, then cut into particles by a granulator, and then the obtained particles were placed in a vacuum drying oven for drying to obtain particles;

[0060] (4) Purification: 40g of the particles were weighed, 80ml of xylene was added and heated to 125°C to reflux for 2h, then 80ml of acetone was poured in, cooled for 30min to a temperature of 30°C, then methanol was added and filtered to obtain a precipitate, which was dried in a vacuum drying oven to obtain SEBS-g-DM.

[0061] (II) Preparation of the polypropylene composition

[0062] (1) Dry premixing: 500 g of polypropylene, 40 g of SEBS-g-DM and 30 g of whisker Si were mixed uniformly after being dried in a vacuum drying oven to obtain a premix;

[0063] (2) Extrusion granulation: the premix was extruded by a twin-screw machine, the screw rotation speed was 100 r / min, and the temperature of the twin-screw machine was 240°C;

[0064] (3) Granulation drying: the drawbar prepared in step (2) was cooled with water, then granulated by a granulator, and the prepared granules were dried in a vacuum drying oven to obtain granules;

[0065] (4) Preparation of a sample: an experimental sample was prepared by an injection molding machine, and the temperature of the injection molding machine was 265°C.

[0066] Examples 2-9

[0067] The polypropylene composition was prepared according to the method of Example 1, except that the weight of polypropylene, SEBS-g-DM and whisker Si in step (1) was adjusted, and the specific values are shown in Table 1.

[0068] Comparative Examples 1-5

[0069] The polypropylene composition was prepared according to the method of Example 1, except that the weight of polypropylene, SEBS-g-DM and whisker Si in step (1) was adjusted, and the specific values are shown in Table 1.

[0070] Comparative Example 6

[0071] The polypropylene composition was prepared according to the method of Example 1, except that in the preparation of SEBS-g-DM, the maleic acid diethyl ester in step (1) was replaced by maleic acid dioctyl ester.

[0072] Comparative Example 7

[0073] The polypropylene composition was prepared according to the method of Example 1, except that no dicumyl peroxide was added in the preparation of SEBS-g-DM, the hydrogenated styrene-butadiene and maleic acid dioctyl ester were physically mixed, and steps (2)-(4) were not performed.

[0074] Comparative Example 8

[0075] The polypropylene composition was prepared according to the method of Example 1, except that no dicumyl peroxide was added in the preparation of SEBS-g-DM, the hydrogenated styrene-butadiene and maleic acid diethyl ester were physically mixed, and steps (2)-(4) were not performed.

[0076] Comparative Example 9

[0077] The polypropylene composition was prepared according to the method of Example 1, except that whisker Si was replaced by whisker alumina when preparing the polypropylene composition.

[0078] Table 1

[0079]

[0080]

[0081] Test Example 1

[0082] (1) Impact strength test

[0083] The high-toughness high-strength polypropylene plastic provided by the above examples and comparative examples was tested according to GB / T1843-2008 standard, and the test results are shown in Table 2. The sample size was 80mm x 10mm x 4mm, and a V-shaped notch with a depth of 2mm.

[0084] (2) Tensile strength test

[0085] The high-toughness high-strength polypropylene plastic provided by the above examples and comparative examples was tested according to GB / T1040-2006 standard to test the tensile strength of the high-toughness high-strength polypropylene plastic, and the test results are shown in Table 2. The sample size was 150mm x 10mm x 4mm, and the dumbbell shape, the test speed was 50mm / min.

[0086] Table 2

[0087]

[0088]

[0089] From the above table, it can be seen that the impact strength of polypropylene alone in Comparative Example 5 is higher than that of Comparative Example 1 because the content of SEBS-g-DM in Comparative Example 1 is too low, and the content of whisker Si is too high, which may cause defects due to stress concentration, thereby reducing the impact strength; the reason why the tensile strength of Comparative Example 5 is higher than that of Comparative Examples 2 and 4 is the same as the above principle, when the whisker Si or SEBS-g-DM is excessive, it may cause defects due to stress concentration, thereby reducing the tensile strength.

[0090] Examples 10-20

[0091] The polypropylene composition was prepared according to the method of Example 1, except that the weight of hydrogenated styrene-butadiene, diethyl maleate and dicumyl peroxide in step (1) when preparing SEBS-g-DM was adjusted, and the specific values are shown in Table 3.

[0092] Table 3

[0093] Hydrogenated styrene-butadiene / g Diethyl maleate / g Dicumyl peroxide / g Example 10 100 10 1.2 Example 11 100 9 1.2 Example 12 100 9 1.4 Example 13 100 9 1 Example 14 100 10 1 Example 15 100 11 1 Example 16 100 11 1.2 Example 17 100 10 1.6 Example 18 100 9 0.9 Example 19 100 8 1.4 Example 20 100 12 1.4

[0094] Test Example 2

[0095] Impact strength test and tensile strength test were carried out according to the method of Test Example 1, and the test results were shown in Table 4.

[0096] Table 4

[0097]

[0098]

[0099] Examples 21-25

[0100] Polypropylene compositions were prepared according to the method of Example 1, except that the screw rotation speed of the twin-screw extruder in step (2) was adjusted when preparing SEBS-g-DM, and the specific values were shown in Table 5.

[0101] Test Example 3

[0102] Impact strength test and tensile strength test were carried out according to the method of Test Example 1, and the test results were shown in Table 5.

[0103] Table 5

[0104]

[0105]

[0106] Examples 26-30

[0107] Polypropylene compositions were prepared according to the method of Example 1, except that the temperature of the twin-screw extruder in step (2) in step (ii) was adjusted when preparing polypropylene compositions, and the specific values were shown in Table 6.

[0108] Test Example 4

[0109] Impact strength test and tensile strength test were carried out according to the method of Test Example 1, and the test results were shown in Table 6.

[0110] Table 6

[0111] Temperature (°C) impact strength (kJ / m 2 ) Tensile strength (MPa) Example 26 220 6.1 28.3 Example 27 230 7.5 30.7 Example 28 250 8.8 32.6 Example 29 210 4.3 25.6 Example 30 260 4.7 27.9

[0112] Examples 31-35

[0113] The polypropylene composition was prepared according to the method of Example 1, except that the temperature of the twin-screw extruder in step (2) of step (1) was adjusted when preparing SEBS-g-DM, and the specific values are shown in Table 7.

[0114] Test Example 5

[0115] The impact strength test and the tensile strength test were performed according to the method of Test Example 1, and the test results are shown in Table 7.

[0116] Table 7

[0117] Temperature (°C) Impact strength (kJ / m 2 )]]> Tensile strength (MPa) Example 31 190 6.1 28.3 Example 32 210 7.5 30.7 Example 33 225 6.9 29.5 Example 34 180 4.7 27.9 Example 35 230 4.8 26.3

[0118] The preferred embodiments of the present application are described in detail above, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. A polypropylene composition, characterized in that, The composition comprises: 2-10 parts by weight of SEBS-g-DM and 2-10 parts by weight of whisker Si, relative to 100 parts by weight of polypropylene; wherein, The SEBS-g-DM is a hydrogenated styrene-butadiene block copolymer elastomer grafted with maleic acid diethyl ester.

2. The composition of claim 1, wherein, The mass ratio of the polypropylene to the SEBS-g-DM is 100:6-8. Preferably, the mass ratio of the polypropylene to the whisker Si is 100:5-7.

3. The composition according to claim 1 or 2, wherein, The weight average molecular weight of the SEBS-g-DM is 80-150 thousand. And / or, the structural units provided by the hydrogenated styrene in the SEBS-g-DM account for 28-33% of the total weight of the SEBS-g-DM.

4. The composition according to any one of claims 1-3, wherein, The grafting rate of the maleic acid diethyl ester in the SEBS-g-DM is 2.3-4.5 wt%.

5. The composition according to any one of claims 1-4, wherein, The preparation method of the SEBS-g-DM is: mixing and reacting hydrogenated styrene-butadiene, maleic acid diethyl ester and dicumyl peroxide.

6. The composition of claim 5, wherein, The mass ratio of the hydrogenated styrene-butadiene to the maleic acid diethyl ester is 100:9-11, preferably 100:9.5-10.

5.

7. The composition according to claim 5 or 6, wherein, The mass ratio of the hydrogenated styrene-butadiene to the dicumyl peroxide is 100:1-1.4, preferably 100:1.1-1.

4.

8. The composition according to any one of claims 4-6, wherein, The reaction temperature is 190-225℃, and the reaction time is 10-25min. Preferably, the reaction temperature is 210-223℃, and the reaction time is 15-20min.

9. A process for the preparation of a polypropylene composition, wherein, The method comprises the following steps: (1) drying and uniformly mixing the polypropylene, the SEBS-g-DM and the whisker Si to obtain a premix; (2) extruding and granulating the premix; The SEBS-g-DM is a hydrogenated styrene-butadiene block copolymer elastomer grafted with maleic acid diethyl ester.

10. The production method according to claim 9, wherein The extrusion temperature is 220-250℃, and the extrusion time is 10-25min. Preferably, the extrusion temperature is 230-250℃, and the extrusion time is 15-20min.

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