A polypropylene composition and its preparation method and application

Abstract

The invention discloses a polypropylene composition and a preparation method and application thereof, belonging to the technical field of polymer materials. The product is prepared by introducing styrene-ethylene-butylene-styrene block copolymer into a polypropylene resin matrix to form a resin system, and simultaneously selecting a silicate filler with a specific whiteness and a sorbitol-based transmittance enhancer for compounding. Under the synergistic effect of the components, the product can not only achieve a higher light transmittance, but also has a high surface energy and ideal spray paint adhesion.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a polypropylene composition and a preparation method and application thereof. Background Art

[0002] Polypropylene is widely used in the fields of automobiles, electronic products, and home appliances because of its ideal mechanical properties and processing properties. However, when polypropylene materials are used in the automotive field, especially in the preparation of automotive exterior parts, specific exterior parts require higher light transmittance to meet the use standards. For this reason, people generally introduce transmittance enhancers into the products to improve the transparency of the products. However, the transmittance enhancement degree of these transmittance enhancers when used in small amounts is still difficult to meet the use requirements. In addition to increasing production costs, introducing large amounts may also cause other performance to be weakened.

[0003] On the other hand, automotive exterior parts based on polypropylene generally need to be painted, so the substrate needs to have a certain surface energy so that the paint layer can be physically anchored to the material. However, due to the selection of fillers and additives, it is difficult to achieve ideal paint adhesion effects with existing high-transmittance polypropylene materials. Summary of the invention

[0004] Based on the defects of the prior art, the purpose of the present invention is to provide a polypropylene composition. The product is formed by compounding a resin system by introducing styrene-ethylene-butylene-styrene block copolymer (SEBS) into a polypropylene resin matrix, and simultaneously compounding a silicate filler with a specific whiteness and a sorbitol-type transmittance enhancer. Under the synergistic effect of each component, the product can not only achieve a higher light transmittance, but also has a high surface energy and ideal paint adhesion.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A polypropylene composition comprising the following components in parts by weight:

[0007] 45-80 parts of polypropylene resin, 10-40 parts of SEBS, 5-35 parts of silicate filler, 0.1-0.5 parts of permeability enhancer;

[0008] The whiteness of the silicate filler is ≥94%;

[0009] The permeation enhancer is a sorbitol-based permeation enhancer.

[0010] Preferably, the whiteness of the silicate filler is tested by direct testing using a whiteness meter.

[0011] The specific test method is to use the WGB-2A desktop whiteness meter produced by Shanghai Precision Instruments, put a light-shielding black tube on the measuring space in advance and adjust the zero value with the instrument zero adjustment potentiometer. After the instrument zero position is stable, remove the black tube; put the standard whiteness plate on it and adjust the standard whiteness value with the instrument calibration potentiometer to calibrate the instrument, and then remove the standard whiteness plate; measure the sample to be tested to determine the whiteness value.

[0012] SEBS is often used as a toughening agent in plastic products due to its good elasticity. In the technical solution of the present invention, SEBS is introduced into the polypropylene resin matrix as a synergistic component, which can not only improve the light transmittance of the product, but also make the product have a higher surface energy and high adhesion when spraying. On the other hand, since the surface energy of the product is related to the roughness, and the roughness of the product is largely related to the introduction of fillers, if the introduction of fillers is insufficient, it is difficult for the product to achieve sufficient surface energy. However, if too much filler is introduced or the type introduced is inappropriate, the light transmittance of the product will be affected. For this reason, the technical solution of the present invention introduces high-whiteness silicate fillers and sorbitol transmittance enhancers into the composite resin matrix of polypropylene + SEBS for compounding. Under the joint action of the two, the product can ensure a higher light transmittance. At the same time, the polar functional groups on the surface of the filler can optimize its dispersion uniformity in the matrix resin and ensure sufficient surface energy. If other types of fillers are selected, such as the commonly used titanium fillers, even if the whiteness is high, the light transmittance of such materials is low, and it is still difficult to achieve the ideal surface energy. Although the silicate fillers with insufficient whiteness can guarantee the surface energy, the light transmittance of the product is not ideal. Similarly, other types of transmittance enhancers cannot play an effective role in this system and cannot take into account both the light transmittance and surface energy of the product.

[0013] Preferably, the polypropylene composition comprises the following components in parts by weight:

[0014] 55-75 parts of polypropylene resin, 15-35 parts of SEBS, 10-30 parts of silicate filler, and 0.1-0.5 parts of permeability enhancer.

[0015] More preferably, the mass ratio of the polypropylene resin to SEBS is (60-70): (20-30).

[0016] The use of the matrix resin in the above preferred proportions can make the filler and the transmittance enhancer dispersed and work better, thereby achieving better light transmission performance and surface energy.

[0017] Preferably, the mass content of the polypropylene resin in the polypropylene composition is ≥45wt%.

[0018] More preferably, the ratio of the total mass of the polypropylene resin and SEBS to the mass of the silicate filler is (9:1) to (7:3).

[0019] Preferably, the polypropylene resin has a melt mass flow rate of 1 to 100 g / 10 min at 230° C. and a load of 2.16 kg according to ISO 1133-2011.

[0020] More preferably, the melt mass flow rate of the polypropylene resin at 230° C. and a load of 2.16 kg is 30 to 60 g / 10 min.

[0021] Preferably, the weight average molecular weight of the SEBS is 20,000 to 120,000;

[0022] The weight average molecular weight of the SEBS is measured by gel permeation chromatography.

[0023] The specific test method is: dissolve an appropriate amount of SEBS in tetrahydrofuran, filter the resulting solution with a 0.22μm filter membrane, and use a TDA302 gel permeation spectrometer produced by Viscotek, USA, to test the weight-average molecular weight. The detectors used are differential and laser scattering detectors, the eluent is tetrahydrofuran, the flow rate is 1.0 mL / min, the test temperature is 25°C, the mass concentration of the solution is 2-5 g / L, and the standard sample is polystyrene.

[0024] More preferably, the weight average molecular weight of the SEBS is 30,000-75,000.

[0025] More preferably, the weight average molecular weight of the SEBS is 35,000-50,000.

[0026] The polymer particle sizes of SEBS and polypropylene resin are not the same, so homogeneous compatibility does not occur during the combination process. At this time, the weight-average molecular weight of SEBS will also change its dispersibility in polypropylene resin and the traction effect on the filler. The inventors have found through research that when SEBS with the above molecular weight is selected, the prepared product can achieve higher light transmittance while taking into account the surface energy.

[0027] Preferably, the SEBS has a melt mass flow rate of 1 to 15 g / 10 min at 230° C. and a load of 2.16 kg according to ISO 1133-2011.

[0028] Preferably, the silicate filler includes at least one of silicate and aluminosilicate;

[0029] More preferably, the silicate filler is at least one of talc powder, glass fiber powder, mica powder and quartz powder.

[0030] More preferably, the average particle size of the mica and / or talc and / or quartz powder is 8-16 μm.

[0031] More preferably, the glass fiber powder has an average diameter of 10-13 μm and an average length of 20-50 μm.

[0032] The average particle size of mica and / or talc and / or quartz powder in the silicate filler of the present invention is determined by laser particle size analyzer testing with reference to the particle size distribution laser diffraction method of GB / T19077-2016.

[0033] The average length and average diameter of the glass fiber powder in the silicate filler of the present invention are confirmed by the following method: the glass fiber powder is dispersed in water, and after ultrasonic oscillation treatment, the average length and average diameter are statistically confirmed under a second dimension using an optical microscope.

[0034] Preferably, in the polypropylene composition, the retained average particle size of the silicate filler is 4 to 15 μm.

[0035] The retained average particle size of the silicate filler in the polypropylene composition of the present invention is the average particle size of the silicate filler retained in the product after the specified polypropylene composition is melt-extruded and granulated.

[0036] Preferably, in the polypropylene composition, the retained average particle size of mica and / or talc and / or quartz powder is 4-10 μm.

[0037] Preferably, in the polypropylene composition, the retained average particle size of the glass fiber powder is 10-15 μm.

[0038] The test method for the retained average particle size of the silicate filler of the present invention is: calcining the polypropylene composition at 800° C. for 30 minutes in an air atmosphere, sieving the ash, and then testing and confirming it with a laser particle size analyzer with reference to the laser diffraction method of particle size distribution in GB / T 19077-2016.

[0039] Preferably, the mass ratio of the silicate filler to the permeability enhancer is 1:(0.015-0.04).

[0040] As mentioned above, when silicate fillers and transmittance enhancers are used in combination, the two produce a synergistic effect. On the one hand, the silicate fillers give the product sufficient surface energy. On the other hand, the silicate fillers and transmittance enhancers work together to ensure that the product has a higher transmittance when different filler addition amounts are added. When within the above range, the product can achieve a higher transmittance and the surface energy can be maintained above 24 dyne.

[0041] Preferably, the sorbitol-based permeability enhancer is at least one of 1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]-nonanol, 1,3:2,4-di(3,4-dimethylbenzylidene)-D-sorbitol, diphenylmethylene sorbitol, and di(p-methyldiphenylmethylene) sorbitol.

[0042] Preferably, the components of the polypropylene composition also include 0.1 to 1 part of an antioxidant and 0.1 to 1 part of a light stabilizer.

[0043] More preferably, the antioxidant is at least one of a hindered phenol antioxidant, a phosphite antioxidant, and a thioester antioxidant.

[0044] More preferably, the antioxidant is a mixture of a hindered phenol antioxidant and a phosphite antioxidant, and the mass ratio of the two is (0.8-1.2):(0.8-1.2).

[0045] More preferably, the light stabilizer is a hindered amine light stabilizer.

[0046] Preferably, the components of the polypropylene composition also include 0.1 to 3 parts of a processing aid.

[0047] More preferably, the processing aid includes at least one of an antistatic agent, a lubricant, an antibacterial agent, and a colorant.

[0048] It should be noted that the components of the polypropylene composition of the present invention may include, but are not limited to, the above-mentioned processing aids according to actual needs. Under the premise of not affecting the light transmittance and surface energy effects of the polypropylene composition, those skilled in the art may select various processing aids to give the product other performance effects. For example, in order to give the product antistatic properties to achieve safety in the automotive field, an appropriate amount of antistatic agent may be added, and in order to increase the processing efficiency and demoulding effect of the product, an appropriate lubricant may be introduced into the product, etc.

[0049] Another object of the present invention is to provide a method for preparing the polypropylene composition, comprising the following steps:

[0050] The components are mixed uniformly and then melt-extruded and granulated in a screw extruder to obtain the polypropylene composition.

[0051] Preferably, when the components are melt-extruded, the temperature zones of the screw extruder are set to 170-190°C in zone 1, 170-190°C in zone 2, 190-210°C in zone 3, 190-210°C in zone 4, 190-210°C in zone 5, 200-220°C in zone 6, 200-220°C in zone 7, 200-220°C in zone 8, 200-220°C in zone 9, and 200-220°C in zone 10, the screw speed is 350-450rpm, and the screw aspect ratio is (40-50):1.

[0052] The preparation method of the polypropylene composition of the present invention is simple to operate, has small requirements on equipment, and can realize industrial-scale production.

[0053] Another object of the present invention is to provide application of the polypropylene composition in the preparation of automobile decorative parts.

[0054] Preferably, the automobile decorative parts include at least one of an integrated luminous front face, a luminous tailgate back panel, a luminous door panel, a luminous fender, a luminous trim, and an intelligent control panel.

[0055] Another object of the present invention is to provide an automobile decorative part comprising the polypropylene composition of the present invention.

[0056] The polypropylene composition of the present invention has an ideal light transmittance effect, and can achieve a larger surface energy in water and solvent tests, and can achieve higher adhesion for water-based and paint coatings, so it is very suitable for the above-mentioned automotive decorative parts that have high requirements for light transmittance and paint film adhesion.

[0057] The beneficial effect of the present invention is that the present invention provides a polypropylene composition, which is formed by introducing SEBS into a polypropylene resin matrix to form a resin system, and simultaneously selecting a silicate filler with a specific whiteness and a sorbitol-based transmittance enhancer for compounding. Under the synergistic effect of each component, the product can not only achieve a higher light transmittance, but also has a high surface energy and ideal paint adhesion. DETAILED DESCRIPTION

[0058] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments and comparative examples, the purpose of which is to understand the content of the present invention in detail, rather than to limit the present invention. All other embodiments obtained by those of ordinary skill in the art without making creative work premise belong to the protection scope of the present invention. The experimental reagents and instruments involved in the implementation of the present invention, unless otherwise specified, are all commonly used common reagents and instruments.

[0059] Embodiments 1 to 20

[0060] An embodiment of a polypropylene composition and a preparation method and application thereof according to the present invention, the components of the polypropylene composition are shown in Table 1.

[0061] The method for preparing the polypropylene composition comprises the following steps:

[0062] The components are mixed uniformly and then melt-extruded and granulated in a screw extruder to obtain the polypropylene composition.

[0063] When the components are melt-extruded, the temperature zones of the screw extruder are set to 180°C in zone 1, 180°C in zone 2, 200°C in zone 3, 200°C in zone 4, 200°C in zone 5, 210°C in zone 6, 210°C in zone 7, 210°C in zone 8, 210°C in zone 9, and 210°C in zone 10, the screw speed is 400rpm, and the screw aspect ratio is 48:1.

[0064] Comparative Examples 1 to 10

[0065] The difference between the comparative examples and the embodiments is only in the types and proportions of components, as shown in Table 2.

[0066] Among the components described in each embodiment and comparative example,

[0067] The polypropylene resin 1 is PP H9018 produced by Sinopec, and has a melt flow rate of 60 g / 10 min at 230° C. and a load of 2.16 kg;

[0068] The polypropylene resin 2 is PP 320 powder produced by Sinopec Maoming, and the melt flow rate is 32 g / 10 min at 230° C. and 2.16 kg load;

[0069] The SEBS 1 is SEBS 1643 produced by Kraton, USA, with a weight average molecular weight of 40,000;

[0070] The SEBS 2 is SEBS1652 produced by Kraton, USA, with a weight average molecular weight of 35,000;

[0071] The SEBS 3 is SEBS1657 produced by Kraton, USA, with a weight average molecular weight of 50,000;

[0072] The SEBS 4 is SEBS1651 produced by Kraton, USA, with a weight average molecular weight of 110,000;

[0073] The SEBS 5 is SEBS1726 produced by Kraton, USA, with a weight average molecular weight of 30,000;

[0074] The SBS is SBS1153 produced by Kraton, USA, with a weight average molecular weight of 40,000;

[0075] The ABS is ABSKF730 produced by Kingfa Science & Technology, with a weight average molecular weight of 55,000;

[0076] The SBR is SBR1605 produced by Dow Chemical, with a weight average molecular weight of 55,000;

[0077] The glass fiber powder is MF7904 produced by Taishan Fiberglass, with an average diameter of 12 μm, an average length of 25 μm, and a whiteness of 94%;

[0078] The mica powder is W-600 produced by Huajing Mica, and after screening, the average particle size is 15 μm and the whiteness is 94%;

[0079] The quartz powder is produced by Wuhan Jiyesheng, and after screening, the average particle size is 10 μm and the whiteness is 94%;

[0080] The talcum powder 1 is BHS1851 produced by Xufeng Powder, and after screening, the average particle size is 12 μm and the whiteness is 94%;

[0081] The talcum powder 2 is 1250 talcum powder produced by Lingshou County Chengnuo Mineral Products Co., Ltd., with an average particle size of 10 μm and a whiteness of 90% after screening;

[0082] The montmorillonite is I.3PS produced by NANOCOR in the United States, with an average particle size of 10 μm and a whiteness of 85%;

[0083] The titanium dioxide is TS1511 produced by Chemours, with a whiteness of 95%;

[0084] The permeation enhancer 1 is NX8000K produced by Milliken, a sorbitol-based permeation enhancer, 1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]-nonanol;

[0085] The permeation enhancer 2 is Millad3988 produced by Milliken, a sorbitol permeation enhancer, 1,3:2,4-di(3,4-dimethylbenzylidene)-D-sorbitol;

[0086] The permeability enhancer 3 is NA-21 produced by Aidico, a metal phosphate;

[0087] The permeability enhancer 4 is sodium benzoate produced by Shanxi Chemical Research Institute;

[0088] The antioxidant is a mixture of a commercially available hindered phenol antioxidant and a phosphite antioxidant in a mass ratio of 1:1;

[0089] The light stabilizer is a commercially available hindered amine light stabilizer.

[0090] Unless otherwise specified, the components and raw materials used in the embodiments and comparative examples of the present invention are all commercially available raw materials, and the components and raw materials used in each parallel experiment are all of the same kind.

[0091] The test method for the retained average particle size of the filler in each product in the embodiments and comparative examples is as follows: each product is calcined at 800° C. for 30 min in air, and then ash is sieved, and the particle size distribution is confirmed by laser diffraction method using a laser particle size analyzer with reference to GB / T 19077-2016.

[0092] Table 1

[0093]

[0094] Table 2

[0095]

[0096] In order to verify the performance of the polypropylene composition of the present invention, the products prepared in each embodiment and comparative example were subjected to the following performance tests, and the specific steps are as follows:

[0097] (1) Light transmittance test: Each product was injection molded into a 100*100*3mm test square plate, and then tested according to GB 2410-2008;

[0098] (2) Surface energy test: Water and α-bromonaphthalene were added to the surface of the test square plate prepared in step (1) to test the liquid contact angle, and then the surface energy of the product was tested by the Owens two-liquid method.

[0099] The test results are shown in Tables 3 and 4.

[0100] Table 3

[0101]

[0102] Table 4

[0103]

[0104] It can be seen from Table 3 and Table 4 that the polypropylene composition of the present invention has excellent performance, not only the light transmittance can reach 60% or more, but also the surface energy of the product can reach at least 24 dyne, with ideal paint adhesion, and is very suitable for automotive decorative parts. According to Examples 1 and 4 to 7, it can be seen that in the matrix resin, the proportion of SEBS will affect the dispersion effect and light transmittance of the product. As the content of SEBS increases, the light transmittance of the product will increase, while the surface energy of the product will fluctuate. When the ratio of polypropylene resin to SEBS is (60 to 70): (20 to 30), the product can take into account both the best light transmittance and surface energy. On the other hand, it can be seen from Examples 1 and 9 to 12 that, probably because the particles and molecular chains of SEBS and polypropylene resin are different, as the molecular weight of SEBS increases, its dispersibility in polypropylene resin and its traction effect on fillers also change, and its overall light transmittance is also different. Moreover, it will also change the surface adhesion of the product within a certain range. When the weight average molecular weight of SEBS is between 30,000 and 75,000, the product can obtain a higher light transmittance.

[0105] In contrast, SEBS is not used in the products of Comparative Examples 1 to 3 in combination with polypropylene resin. Although the surface energy of the products is relatively high, the transmittance cannot reach more than 60%. It can be seen from the products of Comparative Examples 4 to 6 and Examples 1 and 13 to 15 that in order to achieve high transmittance and high surface energy, the selection of fillers cannot be arbitrary. In addition to the need to use specific silicate fillers, it is also necessary to require a high whiteness, otherwise the expected performance cannot be achieved. According to Comparative Examples 7 to 9, it can be seen that the use of a transmittance enhancer is also a key factor in the products of the present invention. Different types of transmittance enhancers are different in addition to the transmittance enhancement effect achieved by the products. Even if the amount of inappropriate types is increased, the improvement in transmittance is very limited. Moreover, the transmittance enhancer will also affect the dispersibility of the filler after being compatible and compounded with the matrix resin and the filler. The surface roughness of the product is different. If a type other than that specified in the present invention is selected, the surface energy of the product may be weakened.

[0106] According to Example 1 and Examples 17 to 20 and Comparative Example 10, it can be seen that in the product of the present invention, when the filler ratio is fixed, the amount of transmittance enhancer added will affect the surface energy of the product. The main reason is that the two actually produce a synergistic effect. The use of transmittance enhancer within a suitable range can ensure that the filler is evenly dispersed under the premise of ensuring transmittance, and the product surface has sufficient roughness. However, if too much is added, the transmittance of the product will not increase further, but will reduce the dispersion uniformity of the filler and weaken the surface energy of the product. Therefore, it is necessary to limit the addition amount within a specific range. When the mass ratio of silicate filler to transmittance enhancer is in the range of 1: (0.015 to 0.04), the surface energy of the product can be maintained at a higher level.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A polypropylene composition, characterized in that The composition comprises the following components in parts by weight: 55-75 parts of polypropylene resin, 15-35 parts of SEBS, 10-30 parts of silicate filler, 0.1-0.5 parts of permeability enhancer; the whiteness of the silicate filler is ≥94%; The weight average molecular weight of the SEBS is 20000-120000; The permeation enhancer is a sorbitol-based permeation enhancer.

2. The polypropylene composition according to claim 1, characterized in that The mass ratio of the total mass of the polypropylene resin and SEBS to the mass of the silicate filler is (9:1) to (7:3).

3. The polypropylene composition according to claim 1, characterized in that The silicate filler includes silicate.

4. The polypropylene composition according to claim 3, characterized in that The silicate filler is at least one of talcum powder, glass fiber powder, mica powder and quartz powder.

5. The polypropylene composition according to claim 4, characterized in that The average particle size of the mica and / or talc and / or quartz powder is 8-16 μm; and / or the average diameter of the glass fiber powder is 10-13 μm and the average length is 20-50 μm.

6. The polypropylene composition according to claim 1, characterized in that The mass ratio of the silicate filler to the permeability enhancer is 1:(0.015-0.04).

7. The polypropylene composition according to claim 1, characterized in that The components of the polypropylene composition also include 0.1 to 1 part of an antioxidant and 0.1 to 1 part of a light stabilizer; the antioxidant is at least one of a hindered phenol antioxidant, a phosphite antioxidant, and a thioester antioxidant; and the light stabilizer is a hindered amine light stabilizer.

8. The method for preparing the polypropylene composition according to any one of claims 1 to 7, characterized in that: The following steps are involved: The components are mixed uniformly and then melt-extruded and granulated in a screw extruder to obtain the polypropylene composition.

9. Use of the polypropylene composition according to any one of claims 1 to 7 in the preparation of automotive decorative parts.

10. The use according to claim 9, characterized in that The automobile decorative parts include at least one of an integrated luminous front face, a luminous tailgate back panel, a luminous door panel, a luminous fender, a luminous trim, and an intelligent control panel.

11. An automobile decorative component, characterized in that: The invention comprises the polypropylene composition according to any one of claims 1 to 7.

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