Soft-touch polypropylene composite material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of high polymer materials, and particularly relates to a soft-touch polypropylene composite material as well as a preparation method and application thereof. The polypropylene composite material comprises the following raw material components: soft polypropylene resin, PP resin, a flexibilizer, a polyhydroxy polymer, glass fibers, a compatilizer and a lubricant. The soft polypropylene resin comprises co-polypropylene with a melt index of 0.9-5.5 g / 10min under the condition of 230 DEG C / 2.16 kg, and the ethylene content in the co-polypropylene is greater than or equal to 35%; the compatilizer comprises a polypropylene-maleic anhydride graft, and the grafting rate is 0.8-1.3 wt%; the lubricant comprises modified ethylene bis stearamide and a dendritic polymer containing polyfunctional groups; the functional groups in the dendritic polymer containing the polyfunctional groups comprise at least two of hydroxyl, carboxyl, carbonyl and amino. The polypropylene composite material prepared by the invention has the advantages of favorable impact property, soft touch feeling and low odor.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and particularly relates to a polypropylene composite material with a soft touch, a preparation method and an application thereof. Background Art

[0002] With the rapid development of new energy vehicles, the demand for lightweight and beautiful automotive materials is getting higher and higher. As one of the most widely used materials in vehicles, polypropylene composite materials are also facing new development opportunities and challenges. At present, the interior materials of new energy vehicles use a lot of soft leather and rubber coating to avoid the cheap feeling brought by the use of plastic materials, which will increase the cost accordingly.

[0003] Soft-touch polypropylene composite materials have attracted more and more attention because they have the feel of soft rubber materials, matte finish, and scratch resistance. However, soft-touch polypropylene composite materials are prepared by compounding polypropylene resin and glass fiber. Glass fiber and polypropylene resin have poor compatibility. In order to obtain good compatibility and impact strength, the conventional preparation method is to use a large amount of polypropylene grafted maleic anhydride as a compatibilizer and a large amount of ethylene-octene copolymer (POE) as a toughening agent to ensure the soft touch and high impact strength of the material. However, this preparation method will make the prepared polypropylene composite material have a noticeable odor, and the cost is high, which is not conducive to large-scale promotion and application.

[0004] Therefore, it is of great significance to provide a polypropylene composite material with low odor, good soft touch and impact strength. Summary of the invention

[0005] The present invention aims to solve one or more technical problems existing in the above-mentioned prior art and at least provide a beneficial choice. Specifically, the present invention provides a polypropylene composite material having good soft touch, impact strength and low odor.

[0006] The inventive concept of the present invention: the raw material components of the polypropylene composite material of the present invention include soft polypropylene resin, PP resin, toughening agent, polyhydroxy polymer, glass fiber, compatibilizer, and lubricant; the soft polypropylene resin includes copolymerized polypropylene with a melt index of 0.9-5.5g / 10min under the condition of 230℃ / 2.16kg, and the ethylene content in the copolymerized polypropylene is ≥35%; the compatibilizer includes polypropylene-maleic anhydride grafts with a grafting rate of 0.8-1.3wt%; the lubricant includes modified ethylene bisstearamide and dendritic polymers containing multiple functional groups. The soft polypropylene resin has a high ethylene content, low modulus and hardness, and can give the material a soft touch and good impact strength. The hydroxyl groups carried by the polyhydroxy polymer can react with the glass fiber to increase the compatibility of the system, and the main chain of the polyhydroxy polymer also has good compatibility with the resin, so that the entire system forms a micro-crosslinked structure to improve the impact performance of the material. In addition, polyhydroxy polymers and toughening agents also have a synergistic toughening effect. The two work together to improve the impact performance of the material and reduce the hardness of the material. The modified ethylene bisstearamide and the dendritic polymer containing multiple functional groups are compounded to form a lubricating system. Because the amino, hydroxyl, carboxyl and other functional groups it carries can provide more sites for melting reaction with the hydroxyl groups on the glass fiber, it can significantly improve the dispersibility of the glass fiber in the resin and improve the compatibility of the glass fiber with the resin; the modified ethylene bisstearamide can prevent the glass fiber from being exposed, improve the material melt index, improve the fluidity, reduce the screw torque during melt extrusion, and reduce mechanical wear; that is, the compounded lubricant system can improve the fluidity and impact performance of the composite material. The grafting rate in the compatibilizer is high, and the residual maleic anhydride monomer is small, which can ensure that the compatibility between the resin and the glass fiber is good when the addition amount is low, and the odor is reduced from the source.

[0007] Therefore, a first aspect of the present invention provides a soft touch polypropylene composite material.

[0008] Specifically, the raw material components of the polypropylene composite material include soft polypropylene resin, PP resin, toughening agent, polyhydroxy polymer, glass fiber, compatibilizer, and lubricant;

[0009] The soft polypropylene resin comprises a copolymer polypropylene having a melt index of 0.9-5.5 g / 10 min at 230° C. / 2.16 kg, wherein the ethylene content of the copolymer polypropylene is ≥35%;

[0010] The compatibilizer comprises polypropylene-maleic anhydride grafts, and the grafting rate of the polypropylene-maleic anhydride grafts is 0.8-1.3wt%;

[0011] The lubricant includes modified ethylene bisstearamide and a dendritic polymer containing multiple functional groups;

[0012] The functional groups in the multifunctional dendrimer include at least two of hydroxyl, carboxyl, carbonyl and amino groups.

[0013] Preferably, the soft polypropylene resin comprises copolymerized polypropylene having a melt index of 1-5 g / 10 min at 230° C. / 2.16 kg, and the ethylene content in the copolymerized polypropylene is ≥40%.

[0014] Preferably, the soft polypropylene resin is selected from GS20 produced by Guangshihua.

[0015] Preferably, the grafting rate of the polypropylene-maleic anhydride graft is 0.8-1.2 wt %.

[0016] Preferably, the compatibilizer is selected from CMG5701 of Jiayirong Polymer Co., Ltd.

[0017] Preferably, the PP resin comprises copolymerized polypropylene or homopolymerized polypropylene with a melt index ≥18 g / 10 min at 230°C / 2.16 kg; further preferably, the PP resin comprises copolymerized polypropylene or homopolymerized polypropylene with a melt index ≥20 g / 10 min at 230°C / 2.16 kg.

[0018] Preferably, the toughening agent includes at least one of ethylene-octene copolymer (POE), ethylene-butene copolymer, and propylene-based elastomer.

[0019] Preferably, the polyhydroxy polymer comprises at least one of hydroxyl-terminated hydrogenated polybutadiene and hydroxyl-terminated polybutadiene; further preferably, the polyhydroxy polymer comprises hydroxyl-terminated hydrogenated polybutadiene; further preferably, the polyhydroxy polymer is selected from Polytail H of Mitsubishi Chemical.

[0020] Preferably, the monofilament diameter of the glass fiber is 8-14 μm; more preferably, the monofilament diameter of the glass fiber is 9-13 μm.

[0021] Preferably, the length of the glass fiber is 2.7-6.5 mm; further preferably, the length of the glass fiber is 3-6 mm.

[0022] Specifically, the glass fiber is chopped glass fiber.

[0023] Preferably, the mass ratio of the modified ethylene bisstearamide and the dendritic polymer containing multifunctional groups is 1:(0.8-1.2); further preferably, the mass ratio of the modified ethylene bisstearamide and the dendritic polymer containing multifunctional groups is 1:(0.9-1.1); further preferably, the mass ratio of the modified ethylene bisstearamide and the dendritic polymer containing multifunctional groups is 1:1.

[0024] Specifically, the modified ethylene bisstearamide is TAF-A.

[0025] Preferably, the multifunctional dendrimer is selected from CYD-P214 of Chenyuan Polymer.

[0026] Specifically, dendritic polymers, also known as branched polymers, are linear polymers with dendrons on each repeating unit.

[0027] Preferably, the polypropylene composite material further comprises an antioxidant.

[0028] Preferably, the antioxidant includes at least one of a phenolic antioxidant and a phosphite antioxidant.

[0029] Preferably, the antioxidant includes at least one of antioxidants 1010 , 1076 , and 168 .

[0030] Preferably, the raw material components of the polypropylene composite material include 9-45 parts of soft polypropylene resin, 36-75 parts of PP resin, 4.5-16.5 parts of toughening agent, 4.5-11 parts of polyhydroxy polymer, 9-33 parts of glass fiber, 2.7-9 parts of compatibilizer, 0.25-0.35 parts of antioxidant, and 0.27-1.1 parts of lubricant, by weight.

[0031] Further preferably, the raw material components of the polypropylene composite material include, by weight, 10-40 parts of soft polypropylene resin, 40-70 parts of PP resin, 5-15 parts of toughening agent, 5-10 parts of polyhydroxy polymer, 10-30 parts of glass fiber, 3-8 parts of compatibilizer, 0.27-0.33 parts of antioxidant, and 0.3-1.0 parts of lubricant.

[0032] The second aspect of the present invention provides a method for preparing the polypropylene composite material with soft touch according to the first aspect of the present invention.

[0033] Specifically, the method for preparing the soft-touch polypropylene composite material comprises the following steps:

[0034] The raw material components are mixed to obtain a mixed material, which is then melt-extruded to obtain the polypropylene composite material with a soft touch.

[0035] Preferably, the mixing is carried out by stirring, the stirring speed is 400-600r / min, and the stirring time is 4-6min; further preferably, the stirring speed is 450-550r / min, and the stirring time is 4.5-5.5min; further preferably, the stirring speed is 500r / min, and the stirring time is 5min.

[0036] Preferably, a twin-screw extruder is used for the melt extrusion, the processing temperature of each zone of the twin-screw extruder is 55-240°C, and the speed of the screw of the twin-screw extruder is 270-500r / min; further preferably, the processing temperature of each zone of the twin-screw extruder is 60-220°C, and the speed of the screw of the twin-screw extruder is 300-450r / min.

[0037] Preferably, the polypropylene composite material needs to be injection molded into a standard test specimen for performance testing.

[0038] Preferably, the process conditions of the injection molding are: the temperature of each zone from the feeding section to the nozzle end is 170-200°C, 170-200°C, 175-210°C.

[0039] Preferably, the injection pressure of the injection molding is 35-65 MPa; further preferably, the injection pressure of the injection molding is 40-60 MPa.

[0040] Preferably, the holding time of the injection molding is 1.8-4.5 s; further preferably, the holding time of the injection molding is 2-4 s.

[0041] The third aspect of the present invention provides a use of the polypropylene composite material with soft touch described in the first aspect of the present invention in automotive materials.

[0042] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0043] (1) The soft polypropylene resin of the present invention has a high ethylene content, low modulus and hardness, and can give the material a soft touch and good impact strength. The hydroxyl groups carried by the polyhydroxy polymer can react with glass fibers to increase the compatibility of the system, and the main chain of the polyhydroxy polymer and the resin also have good compatibility, so that the entire system forms a micro-crosslinked structure, improving the impact performance of the material. In addition, the polyhydroxy polymer and the toughening agent also have a synergistic toughening effect, and the two work together to improve the impact performance of the material.

[0044] (2) The present invention adopts a lubricating system compounded with modified ethylene bis stearamide and a dendritic polymer containing multiple functional groups. Since the amino, hydroxyl, carboxyl and other functional groups carried by the dendritic polymer can provide more sites for melting reaction with the hydroxyl groups on the glass fiber, the dispersibility of the glass fiber in the resin can be significantly improved, and the compatibility of the glass fiber and the resin can be improved; the modified ethylene bis stearamide can prevent the glass fiber from being exposed, improve the material melt index, improve the fluidity, reduce the screw torque, and reduce mechanical wear; the compounded lubricant system can improve the fluidity and impact performance of the composite material. In addition, the grafting rate in the compatibilizer is high, and the residual maleic anhydride monomer is small, which can ensure that the compatibility between the resin and the glass fiber is good when the addition amount is low, and the odor is reduced from the source.

[0045] (3) The preparation method of the present invention is simple, the process operation is easy to implement, and the obtained polypropylene composite material with soft touch can well meet the requirements of materials such as automobile interiors. DETAILED DESCRIPTION

[0046] In order to make the technical scheme of the present invention more clearly understood by those skilled in the art, the following embodiments are listed for illustration. It should be pointed out that the following embodiments do not limit the protection scope of the present invention.

[0047] Unless otherwise specified, the raw materials, reagents or devices used in the following examples can be obtained from conventional commercial sources or by existing known methods.

[0048] The source information of the raw material components related to the examples and comparative examples of the present invention are as follows:

[0049] PP resin 1: EP548R, CNOOC Shell, melt index 28g / 10min at 230℃ / 2.16kg;

[0050] PP resin 2: PPH-Y26, Zhenhai Refining and Chemical, melt index is 28g / 10min at 230℃ / 2.16kg;

[0051] PP resin 3: 7033E3, ExxonMobil, melt index 8 g / 10 min at 230°C / 2.16 kg;

[0052] PP resin 4: BX3900, SK Chemical, melt index 60 g / 10 min at 230°C / 2.16 kg;

[0053] Soft polypropylene resin: GS20, Guangshihua, melt index is 1.2g / 10min at 230℃ / 2.16kg;

[0054] Toughener 1: POE 9061, ExxonMobil, melt index 0.5 g / 10 min at 190°C / 2.16 kg;

[0055] Toughener 2: LLDPE DFDA-7042, Wanhua Chemical, melt index 1.9 g / 10 min at 190°C / 2.16 kg;

[0056] Polyhydroxy polymer: Mitsubishi Chemical, Polytail H;

[0057] Chopped glass fiber: TCR438G-13-4.5, Taishan fiberglass, monofilament diameter 13μm, fixed length 4.5mm;

[0058] Compatibilizer 1: Jiayirong Polymer Co., Ltd., CMG5701;

[0059] Compatibilizer 2: Shenyang Ketong, KT-1, grafting rate less than 8%;

[0060] Antioxidants: Irganox 1010, Irganox 168, BASF, with a mass ratio of 1:2;

[0061] Lubricant 1: TAF-A and CYD-P214, with a mass ratio of 1:1;

[0062] Lubricant 2: TAF-A.

[0063] The raw material components and amounts of the polypropylene composite materials of Examples 1-6 and Comparative Examples 1-7 of the present invention are shown in Table 1.

[0064] Table 1: Raw material components and amounts of polypropylene composite materials of Examples 1-6 and Comparative Examples 1-7 of the present invention (parts by weight, "-" means no addition)

[0065]

[0066]

[0067] The method for preparing the polypropylene composite material in Examples 1-6 comprises the following steps:

[0068] Add each raw material component into a high-speed mixer, adjust the speed of the high-speed mixer to 500 r / min, stir for 5 minutes to obtain a mixture, add the mixture into a twin-screw extruder for extrusion granulation, pelletize after water cooling, and dry to obtain a polypropylene composite material, wherein the temperatures of zones 1 to 8 of the twin-screw extruder are 190° C., 230° C., 230° C., 220° C., 220° C., 220° C., 220° C., respectively, the head temperature is 230° C., and the speed of the screw of the twin-screw extruder is 500 r / min.

[0069] Comparative Example 1

[0070] The difference between Comparative Example 1 and Example 1 is that Comparative Example 1 uses an equal amount of toughening agent 2 to replace toughening agent 1, and uses an equal amount of toughening agent 2 to replace the polyhydroxy polymer, that is, it does not contain toughening agent 1 and polyhydroxy polymer, and the rest is the same as Example 1.

[0071] Comparative Example 2

[0072] The difference between Comparative Example 2 and Example 1 is that Comparative Example 2 uses an equal amount of toughening agent 1 to replace the polyhydroxy polymer, that is, does not contain the polyhydroxy polymer, and the rest is the same as Example 1.

[0073] Comparative Example 3

[0074] The difference between Comparative Example 3 and Example 3 is that Comparative Example 3 uses an equal amount of compatibilizer 2 to replace compatibilizer 1, and the rest is the same as Example 3.

[0075] Comparative Example 4

[0076] The difference between Comparative Example 4 and Example 1 is that Comparative Example 4 uses an equal amount of Lubricant 2 to replace Lubricant 1, and the rest is the same as Example 1.

[0077] Comparative Example 5

[0078] The only difference between Comparative Example 5 and Example 2 is that Comparative Example 5 uses an equal amount of PP resin 3 to replace the light polypropylene resin, and the rest is the same as Example 2.

[0079] Comparative Example 6

[0080] The difference between Comparative Example 6 and Example 6 is that Comparative Example 6 uses an equal amount of PP resin 3 to replace the light polypropylene resin, and the rest is the same as Example 6.

[0081] Comparative Example 7

[0082] Comparative Example 7 is a conventional polypropylene composite material, and its raw material components and amounts are shown in Table 1.

[0083] Performance Testing

[0084] The polypropylene composite materials of Examples 1-6 and Comparative Examples 1-7 were injection molded into standard test specimens, and then performance tests were performed, wherein the process conditions for injection molding were: the nozzle temperature was 190°C, the temperatures of the three sections from the feeding section to the nozzle were 185°C, 185°C, and 190°C, the holding time was 3s, and the injection pressure was 50MPa.

[0085] The test items and test methods are as follows:

[0086] Density: Tested in accordance with ISO 1183-2022 standard;

[0087] Melt index: tested in accordance with ISO 1133-2022 standard;

[0088] Flexural modulus: tested in accordance with ISO 178-2019;

[0089] Izod notched impact strength: tested in accordance with ISO 180-2019 standard;

[0090] Hardness test: Shore hardness D, tested according to GB / T 2411-2008 standard.

[0091] The performance test results of the polypropylene composite materials of Examples 1-6 and Comparative Examples 1-7 are shown in Table 2.

[0092] Table 2: Performance test results of polypropylene composite materials of Examples 1-6 and Comparative Examples 1-7

[0093]

[0094] It can be seen from Table 2 that the polypropylene composite material prepared by the present invention has low hardness, good soft touch, and good impact resistance.

[0095] Comparative Example 1 uses an equal amount of toughener 2 to replace toughener 1, and uses an equal amount of toughener 2 to replace polyhydroxy polymer, that is, does not contain toughener 1 and polyhydroxy polymer, so that the impact strength of Comparative Example 1 is significantly reduced and the hardness is significantly increased. Comparative Example 2 uses an equal amount of toughener 1 to replace polyhydroxy polymer, so that the impact strength of Comparative Example 1 is significantly reduced and the hardness is significantly increased. It can be seen that the toughening effect of linear low-density polyethylene (LLDPE, toughener 2) or POE alone on polypropylene composites is general, and when POE is compounded with polyhydroxy polymer, the terminal hydroxyl groups contained in the polyhydroxy polymer react with the glass fiber to increase the compatibility of the system, so that the entire system forms a micro-crosslinked structure, and thus the toughening effect is better.

[0096] Comparative Example 3 uses an equal amount of compatibilizer 2 to replace compatibilizer 1, which reduces the impact strength and increases the hardness of Comparative Example 3. This indicates that the grafting rate of the general compatibilizer is low, and when the addition amount is the same, the improvement of the mechanical properties of the material is limited. It also indicates that the specific compatibilizer used in the present invention can work together with other components to improve the impact strength and enhance the soft touch.

[0097] Comparative Example 4 uses an equal amount of lubricant 2 to replace lubricant 1, so that the melt index and impact strength of Comparative Example 4 are reduced. It shows that when TAF-A is used alone as a lubricant, the fluidity and impact strength of the composite material will be reduced. This is because after adding the dendritic lubricant, the amino, hydroxyl, carboxyl and other functional groups it carries can provide more sites for melting reaction with the hydroxyl groups on the glass fiber, which can increase the compatibility of the system and have a better internal lubrication effect. Therefore, the fluidity and impact strength of the composite material prepared by compounding lubricant 1 and lubricant 2 are better.

[0098] Comparative Example 5 uses an equal amount of PP resin 3 to replace the light polypropylene resin, and the amount of toughening agent used is 8. Comparative Example 6 uses an equal amount of PP resin 3 to replace the light polypropylene resin, so that the impact strength of Comparative Examples 5-6 is significantly reduced and the hardness is significantly increased, indicating that compared with ordinary impact-resistant copolymer polypropylene resin, the composite material prepared by using soft polypropylene resin has better impact strength and lower hardness. This is because the soft polypropylene resin has a high ethylene content, which can give the material a soft touch and excellent impact strength.

[0099] Comparative Example 7 is a conventional polypropylene composite material, and the composite material prepared therefrom is inferior to that of the present invention in terms of mechanical properties, hardness and feel.

[0100] In summary, the present invention adopts soft polypropylene resin, which can give the material a soft touch and good impact strength. The polyhydroxy polymer and the toughening agent synergistically toughen, and the two work together to improve the impact performance of the material. The lubricating system of modified ethylene bisstearamide and multi-functional dendritic polymer can significantly improve the dispersibility of glass fiber in the resin, improve the compatibility of glass fiber and resin, and improve the fluidity and mechanical properties of the composite material. The grafting rate in the compatibilizer is high, and the residual maleic anhydride monomer is small, which can ensure that the compatibility between the resin and the glass fiber is good when the addition amount is low, and the odor is reduced from the source.

[0101] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the protection scope 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 composite material, characterized in that: The raw material components include soft polypropylene resin, PP resin, toughening agent, polyhydroxy polymer, glass fiber, compatibilizer, and lubricant; The soft polypropylene resin comprises a copolymer polypropylene having a melt index of 0.9-5.5 g / 10 min at 230° C. / 2.16 kg, wherein the ethylene content of the copolymer polypropylene is ≥35%; The compatibilizer comprises polypropylene-maleic anhydride grafts, and the grafting rate of the polypropylene-maleic anhydride grafts is 0.8-1.3wt%; The lubricant includes modified ethylene bisstearamide and a dendritic polymer containing multiple functional groups; The functional groups in the multifunctional dendrimer include at least two of hydroxyl, carboxyl, carbonyl and amino groups.

2. The polypropylene composite material according to claim 1, characterized in that: The PP resin includes copolymerized polypropylene or homopolymerized polypropylene with a melt index of ≥18 g / 10 min under the condition of 230° C. / 2.16 kg.

3. The polypropylene composite material according to claim 1, characterized in that: The toughening agent includes at least one of ethylene-octene copolymer, ethylene-butene copolymer, and propylene-based elastomer; and / or the polyhydroxy polymer includes at least one of hydroxyl-terminated hydrogenated polybutadiene and hydroxyl-terminated polybutadiene.

4. The polypropylene composite material according to claim 1, characterized in that: The monofilament diameter of the glass fiber is 8-14 μm; and / or the length of the glass fiber is 2.7-6.5 mm.

5. The polypropylene composite material according to claim 1, characterized in that: The mass ratio of the modified ethylene bisstearamide to the dendritic polymer containing multiple functional groups is 1:(0.8-1.2).

6. The polypropylene composite material according to any one of claims 1 to 5, characterized in that: The polypropylene composite material also includes an antioxidant.

7. The polypropylene composite material according to claim 6, characterized in that: By weight, the raw material components of the polypropylene composite material include 9-45 parts of soft polypropylene resin, 36-75 parts of PP resin, 4.5-16.5 parts of toughening agent, 4.5-11 parts of polyhydroxy polymer, 9-33 parts of glass fiber, 2.7-9 parts of compatibilizer, 0.25-0.35 parts of antioxidant and 0.27-1.1 parts of lubricant.

8. The method for preparing the polypropylene composite material according to any one of claims 1 to 7, characterized in that: The following steps are involved: The raw material components are mixed to obtain a mixed material, which is then melt-extruded to obtain the polypropylene composite material.

9. The preparation method according to claim 8, characterized in that: The mixing is carried out by stirring, the stirring speed is 400-600r / min, and the stirring time is 4-6min; and / or, a twin-screw extruder is used for the melt extrusion, the processing temperature of each zone of the twin-screw extruder is 55-240°C, and the screw speed of the twin-screw extruder is 270-500r / min.

10. Use of the polypropylene composite material according to any one of claims 1 to 7 in automotive materials.

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