Low-shrinkage and high-gloss polypropylene composition as well as preparation method and application thereof

Abstract

The invention relates to the technical field of high-molecular polymers, and discloses a low-shrinkage and high-gloss polypropylene composition as well as a preparation method and application of the low-shrinkage and high-gloss polypropylene composition. 6 to 29 parts of polyethylene; 0.11 to 1.2 parts of an auxiliary agent; the rubber phase content of the polypropylene is 17-50%; the melt index MIA of the polypropylene at 230 DEG C under the load of 2.16 kg is 1.3 to 60 g / 10 min; the melt index MIB of the polyethylene under the conditions that the temperature is 190 DEG C and the load is 2.16 kg is 0.7-50g / 10min; the density of the polyethylene is 0.920 to 0.961 g / cm < 3 >; according to the invention, polypropylene is used as a main material, polyethylene with a proper structure is added, and through the synergistic effect of polypropylene and polyethylene, the crystal structure and phase structure of the alloy material are changed, the shrinkage rate of polyolefin is obviously reduced, and the glossiness is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of polymer technology, and in particular to a low-shrinkage, high-gloss polypropylene composition, its preparation method, and its application. Background Technology

[0002] Polypropylene possesses excellent toughness, insulation properties, and corrosion resistance, making it widely used in the automotive, home appliance, and furniture industries. However, ordinary impact-resistant polypropylene exhibits significant molding shrinkage, resulting in products with poor dimensional accuracy, unevenness, and large gaps when assembling different parts, thus limiting its application in high-end products.

[0003] CN110964258A discloses a low-shrinkage polypropylene composition, its preparation method, and its application. The low-shrinkage polypropylene composition contains propylene-butadiene copolymer polypropylene, polyethylene, petroleum resin, nano-inorganic fillers, and processing aids. Specifically, based on 100 parts by weight of propylene-butadiene copolymer polypropylene, the content of polyethylene is 10-30 parts by weight, the content of petroleum resin is 1-10 parts by weight, the content of nano-inorganic fillers is 10-30 parts by weight, and the content of processing aids is 0.05-4 parts by weight. Adding inorganic fillers can effectively reduce the molding shrinkage rate of the product, but it will affect gloss, transparency, toughness, and surface condition of the product, and also increase the processing difficulty. Summary of the Invention

[0004] This invention addresses the technical problem that existing technologies reduce shrinkage by adding inorganic fillers, but this can affect the product's gloss and other properties. It provides a low-shrinkage, high-gloss polypropylene composition, its preparation method, and its application, without requiring the addition of inorganic fillers.

[0005] One objective of this invention is to provide a low-shrinkage, high-gloss polypropylene composition comprising the following components, in parts by weight:

[0006] 71-94 parts of polypropylene;

[0007] Polyethylene 6-29 parts;

[0008] Additives: 0.11-1.2 parts;

[0009] The rubber phase content of the polypropylene is 17-50%, preferably 24-30%;

[0010] The polypropylene has a melt flow index (MIA) of 1.3-60 g / 10 min at 230 °C and 2.16 kg load.

[0011] The polyethylene has a melt flow index (MIB) of 0.7-50 g / 10 min at 190°C and a load of 2.16 kg; the polyethylene density is 0.920-0.961 g / cm³. 3 ;

[0012] in,

[0013] The purpose of this invention is to achieve low shrinkage and high gloss properties in a polypropylene composition without adding inorganic fillers. The specific types of polypropylene and polyethylene are not arbitrarily chosen; the polypropylene needs to have a certain rubber phase content to provide impact resistance. Polypropylene and polyethylene have similar melt indices and similar melt compatibility. After blending, the crystallinity of both polyethylene and polypropylene decreases. Simultaneously, polyethylene enters the polypropylene rubber phase, reducing residual stress in the matrix. Both reduced crystallinity and stress contribute to lower shrinkage, and the inclusion of polyethylene in the polypropylene rubber phase also improves gloss.

[0014] According to a preferred embodiment of the present invention, the polypropylene comprises 75-90 parts by weight, preferably 78-88 parts, more preferably 78-85 parts, and even more preferably 78-82 parts; and / or

[0015] The polyethylene is 10-25 parts; preferably 12-22 parts, more preferably 15-22 parts, and even more preferably 18-22 parts.

[0016] According to a preferred embodiment of the present invention, Preferred and / or

[0017] The polypropylene has a molecular weight distribution of 5-11, preferably 6-8; and / or

[0018] The polypropylene has a melt index of 9-30 g / 10 min at 230 °C and 2.16 kg load, preferably 17-30 g / 10 min.

[0019] In a specific embodiment, the molecular weight distribution is 5, 6, 7, 8, 9, 10, and 11.

[0020] In specific embodiments, the number of parts of polypropylene can be 77, 78, 79, 80, 81, 82, 83, 84, or 85. Correspondingly, the total number of parts of polypropylene and polyethylene is 100 parts.

[0021] The melt flow index of polyethylene and polypropylene meets the requirements. Specifically, the values ​​can be 0, 0.1, 0.15, 0.2, 0.25, 0.3, or 0.34.

[0022] According to a preferred embodiment of the present invention, the polyethylene is selected from at least one of high-density polyethylene and linear low-density polyethylene; preferably linear low-density polyethylene;

[0023] Preferably, the density of the high-density polyethylene is 0.954-0.961 g / cm³. 3 ; and / or, the melting point is 132-136℃; and / or, the melt index of the high-density polyethylene at 190℃ and 2.16kg load is 0.7-30g / 10min, preferably 5-20g / 10min;

[0024] And / or, the density of the linear low-density polyethylene is 0.920-0.936 g / cm³. 3 ; and / or, the melting point is 120-125℃; and / or, the melt index of the linear low-density polyethylene at 190℃ and 2.16kg load is 1-50g / 10min, preferably 5-20g / 10min.

[0025] According to a preferred embodiment of the invention, the adjuvant includes a nucleating agent and optionally an antioxidant.

[0026] Preferably, the nucleating agent is at least one selected from sorbitol-based nucleating agents and organophosphate salt nucleating agents; and / or,

[0027] The adjuvant comprises, by weight, 0.03-0.2 parts of nucleating agent and optionally 0.08-1 parts of antioxidant; preferably, 0.04-0.08 parts of nucleating agent and 0.1-0.5 parts of antioxidant.

[0028] In specific embodiments, the antioxidant can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0 parts.

[0029] According to a preferred embodiment of the present invention, the antioxidant comprises one or more of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tris[2,4-di-tert-butylphenyl]phosphite, N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine, and 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene; preferably a complex of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris[2,4-di-tert-butylphenyl]phosphite.

[0030] The second objective of this invention is to provide a method for preparing the low-shrinkage, high-gloss polypropylene composition, comprising: blending polypropylene, polyethylene and additives in parts by weight, followed by melt extrusion and granulation.

[0031] According to a preferred embodiment of the present invention, the blending time is 0.5-5 min, preferably 1-3 min;

[0032] And / or, the extrusion temperature is 180-250℃, preferably 200-230℃.

[0033] The third objective of this invention is to provide the application of the aforementioned low-shrinkage, high-gloss polypropylene composition in the automotive, home appliance, and home furnishing industries.

[0034] The beneficial effects of this invention are as follows: The low-shrinkage, high-gloss polypropylene composition provided by this invention does not contain inorganic fillers. It uses polypropylene with impact resistance (a specific amount of rubber phase) as the main material, and adds polyethylene with a matching melt index. Through the synergistic effect of the two, the crystalline and phase structures of the alloy material are altered, significantly reducing the shrinkage rate of the polyolefin while greatly improving gloss. By selecting the melt index and proportions of polypropylene and polyethylene, the two are mixed to achieve a synergistic effect, effectively changing the crystalline and phase structures, thereby achieving low shrinkage and high gloss, meeting the requirements of various products. The preparation method is simple, the operation is convenient, the controllability is good, and it is easy to implement industrially. Detailed Implementation

[0035] The present invention will be further described below with reference to specific embodiments, but this does not constitute any limitation on the present invention.

[0036] The nucleating agent and antioxidant used in the examples are commercially available types. The nucleating agent is NAP-50, and the antioxidant is compound antioxidant 215, both of which are commercially available products.

[0037] The molding shrinkage rate was tested according to GB / T 17037.4-2003.

[0038] Gloss was tested at a 60° angle according to GB 8807-88.

[0039]

Example 1

[0040] The following components were mixed: 85 parts by weight of polypropylene (melt index of 9 g / 10 min at 230℃ and 2.16 kg load, molecular weight distribution of approximately 9, and rubber phase content of approximately 27%) and linear low-density polyethylene (density of linear low-density polyethylene is 0.934 g / cm³). 3 15 parts of a polypropylene alloy (melt index of 5 g / 10 min at 190℃ and 2.16 kg load), 0.1 parts of an antioxidant, and 0.04 parts of a nucleating agent were mixed in a high-speed mixer for 1 min, and then fed into a twin-screw extruder. The mixture was melt-extruded, granulated, and dried at 230℃ to obtain the polypropylene alloy material.

[0041] The properties of the obtained alloy were tested, and the results are shown in Table 1.

[0042]

Example 2

[0043] 78 parts by weight of polypropylene (melt index of 30 g / 10 min at 230℃ and 2.16 kg load, molecular weight distribution of approximately 7, rubber phase content of 28%) and linear low-density polyethylene (density of linear low-density polyethylene is 0.924 g / cm³) were prepared. 3 22 parts of a polypropylene alloy (melt index of 20 g / 10 min at 190℃ and 2.16 kg load), 0.5 parts of an antioxidant, and 0.08 parts of a nucleating agent were mixed in a high-speed mixer for 3 min, and then fed into a twin-screw extruder. The mixture was melt-extruded and granulated at 200℃ and dried to obtain the polypropylene alloy material.

[0044] The properties of the obtained alloy were tested, and the results are shown in Table 1.

[0045]

Example 3

[0046] The following ingredients were mixed: 80 parts by weight of polypropylene (melt index of 17 g / 10 min at 230℃ and 2.16 kg load, molecular weight distribution of approximately 8, and rubber phase content of 30%) and high-density polyethylene (density of 0.961 g / cm³). 3 20 parts of a polypropylene alloy (melt index of 20 g / 10 min at 190℃ and 2.16 kg load), 0.3 parts of an antioxidant, and 0.06 parts of a nucleating agent were mixed in a high-speed mixer for 2 min, and then fed into a twin-screw extruder. The mixture was melt-extruded, granulated, and dried at 210℃ to obtain the polypropylene alloy material.

[0047] The properties of the obtained alloy were tested, and the results are shown in Table 1.

[0048]

Example 4

[0049] The following ingredients were mixed: 80 parts by weight of polypropylene (melt index of 17 g / 10 min at 230℃ and 2.16 kg load, molecular weight distribution of approximately 8, and rubber phase content of 30%) and linear low-density polyethylene (density of linear low-density polyethylene is 0.924 g / cm³). 3 20 parts of a polypropylene alloy (melt index of 20 g / 10 min at 190℃ and 2.16 kg load), 0.3 parts of an antioxidant, and 0.06 parts of a nucleating agent were mixed in a high-speed mixer for 2 min, and then fed into a twin-screw extruder. The mixture was melt-extruded, granulated, and dried at 210℃ to obtain the polypropylene alloy material.

[0050] The properties of the obtained alloy were tested, and the results are shown in Table 1.

[0051]

Example 5

[0052] The difference from Example 1 is that 1 part antioxidant and 0.2 parts nucleating agent were added. The performance of the resulting material was tested, and the results are shown in Table 2.

[0053] Comparative Example 1

[0054] The following components were mixed: 95 parts by weight of polypropylene (melt index of 1.3 g / 10 min at 230℃ and 2.16 kg load, molecular weight distribution of approximately 11, and rubber phase content of 23%) and linear low-density polyethylene (density of linear low-density polyethylene is 0.918 g / cm³). 3 Five parts of a polypropylene alloy (with a melt index of 1 g / 10 min at 190℃ and 2.16 kg load), 0.08 parts of an antioxidant, and 0.03 parts of a nucleating agent were mixed in a high-speed mixer for 0.5 min, and then fed into a twin-screw extruder. The mixture was melt-extruded, granulated, and dried at 230℃ to obtain the polypropylene alloy material.

[0055] The properties of the obtained alloy were tested, and the results are shown in Table 1.

[0056] Comparative Example 2

[0057] 70 parts by weight of polypropylene (melt index of 30 g / 10 min at 230℃ and 2.16 kg load, molecular weight distribution of approximately 8, rubber phase content of 23%) and high-density polyethylene (density of 0.954 g / cm³) were prepared. 3 30 parts of a polypropylene alloy (melt index of 30 g / 10 min at 190℃ and 2.16 kg load), 1 part of an antioxidant, and 0.2 parts of a nucleating agent were mixed in a high-speed mixer for 5 min, and then fed into a twin-screw extruder. The mixture was melt-extruded and granulated at 180℃ and dried to obtain the polypropylene alloy material.

[0058] Comparative Example 3

[0059] Polypropylene alloy material was prepared according to the method in Example 4, except that polyethylene was not added. The performance of the obtained granules was tested, and the results are shown in Table 1.

[0060] Comparative Example 4

[0061] Polypropylene alloy material was prepared according to the method in Example 4, except that 98 parts were polypropylene and 2 parts were polyethylene. The performance of the obtained granules was tested, and the results are shown in Table 1.

[0062] Comparative Example 5

[0063] Polypropylene alloy material was prepared according to the method in Example 4, except that 65 parts were polypropylene and 35 parts were polyethylene. The performance of the obtained granules was tested, and the results are shown in Table 1.

[0064] Comparative Example 6

[0065] Polypropylene alloy material was prepared according to the method in Example 4, except that the polyethylene density was 0.924 g / cm³. 3 The melt flow index at 190℃ and 2.16kg load was 8 g / 10min. The performance of the obtained granules was tested, and the results are shown in Table 1.

[0066] Comparative Example 7

[0067] Polypropylene alloy material was prepared according to the method in Example 3, except that the polyethylene density was 0.962 g / cm³. 3 The melt flow index at 190℃ and 2.16kg load was 8 g / 10min. The performance of the obtained granules was tested, and the results are shown in Table 1.

[0068] Comparative Example 8

[0069] Polypropylene alloy material was prepared according to the method of Example 2, except that the molecular weight distribution of polypropylene was about 12. The performance of the obtained granules was tested, and the results are shown in Table 1.

[0070] Comparative Example 9

[0071] Polypropylene alloy material was prepared according to the method in Example 1, except that the type of polypropylene was different. The melt index of the polypropylene at 230℃ and 2.16kg load was 9g / 10min, the molecular weight distribution was about 9, and the rubber phase content was about 16%. The performance of the obtained granules was tested, and the results are shown in Table 1.

[0072] Comparative Example 10

[0073] The difference from Example 1 is that 5 parts of inorganic filler talc were added, and the performance of the resulting material was tested. The results are shown in Table 2.

[0074] Comparative Example 11

[0075] The technical solution in the existing patent is as follows: 97 parts by weight of polypropylene (melt index of 10g / 10min at 230℃ and 2.16kg load, melt temperature of 165℃, ethylene content of 5.5%), 3 parts by weight of linear low-density polyethylene (melt index of 20g / 10min at 190℃ and 2.16kg load, molecular weight distribution of 4.5), 0.1 parts by weight of antioxidant, 0.05 parts by weight of hexagonal boron nitride, 0.05 parts by weight of lubricant, and 0.08 parts by weight of nucleating agent are mixed in a high-speed mixer for 3 minutes, and then fed into a twin-screw extruder for melt extrusion granulation at 200℃ and drying to obtain polypropylene alloy material.

[0076] The performance of the obtained materials was tested, and the results are shown in Table 2.

[0077] Table 1

[0078]

[0079]

[0080] Table 2

[0081]

[0082] As can be seen from the data in Table 1:

[0083] The polypropylene content in Comparative Example 1 was 95 parts, which is greater than 71-94 parts. In Comparative Example 2, the polypropylene content was less than 71-94 parts. The shrinkage rate and gloss of Comparative Example 1 were worse than those of the Example.

[0084] The only difference between Comparative Examples 3, 4, and 5 and Example 4 is the amount of polypropylene. Comparing their shrinkage and gloss, it can be seen that the composition of the present invention has a significant advantage in limiting the amount of polypropylene to 71-94 parts, provided that the polypropylene rubber phase and melt index are satisfied.

[0085] Comparative Example 6 and Example 4 are both linear low-density polyethylene, with no difference in density. The only difference is that the melt flow index of Comparative Example 6 is significantly different. Greater than 0.5; Comparative Example 7 and Example 3 are both linear high-density polyethylene, with no difference in density (the supplier's density test had an error range), the only difference being the larger difference in melt flow index in Comparative Example 7. Greater than 0.5. Test results show that the melt flow indexes of polypropylene and polyethylene are matched to meet the requirements. The requirements are favorable for the shrinkage and gloss of the polypropylene composition.

[0086] The data in Table 2 shows that:

[0087] The only difference between Example 5 and Example 1 is the amount of nucleating agent and antioxidant. The amount of antioxidant and nucleating agent in Example 5 does not meet the requirements of 0.04-0.08 parts of nucleating agent and 0.1-0.5 parts of antioxidant. Its shrinkage rate and gloss are worse than those of Example 1.

[0088] The only difference between Comparative Example 10 and Example 1 is the addition of 5 parts of inorganic filler. Its shrinkage rate remained basically unchanged, but its gloss was significantly reduced.

[0089] Any numerical value mentioned in this invention, if there is only a two-unit interval between any minimum and any maximum value, includes all values ​​that increase by one unit each time from the minimum to the maximum value. For example, if the amount of a component, or the value of a process variable such as temperature, pressure, or time, is stated as 50-90, in this specification it means specifically listing values ​​such as 51-89, 52-88… and 69-71 and 70-71, etc. For non-integer values, it may be appropriately considered that a unit is 0.1, 0.01, 0.001, or 0.0001. These are merely some specifically specified examples. In this application, in a similar manner, all possible combinations of numerical values ​​between the listed minimum and maximum values ​​are considered to have been disclosed.

[0090] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A low-shrinkage, high-gloss polypropylene composition, characterized in that, The following components, in parts by weight, 71-94 parts of polypropylene; Polyethylene 6-29 parts; Additives: 0.11-1.2 parts; The rubber phase content of the polypropylene is 17-50%, preferably 24-30%; The polypropylene has a melt flow index (MIA) of 1.3-60 g / 10 min at 230°C and 2.16 kg load. The polyethylene has a melt flow index (MIB) of 0.7-50 g / 10 min at 190°C and a load of 2.16 kg; the polyethylene density is 0.920-0.961 g / cm³. 3 ; in, 2. The low-shrinkage, high-gloss polypropylene composition according to claim 1, characterized in that, The polypropylene comprises, by weight, 75-90 parts, preferably 78-88 parts, more preferably 78-85 parts, and even more preferably 78-82 parts; and / or The polyethylene is 10-25 parts; preferably 12-22 parts, more preferably 15-22 parts, and even more preferably 18-22 parts.

3. The low-shrinkage, high-gloss polypropylene composition according to claim 1 or 2, characterized in that, Preferred and / or The polypropylene has a molecular weight distribution of 5-11, preferably 6-8; and / or The polypropylene has a melt index of 9-30 g / 10 min at 230 °C and 2.16 kg load, preferably 17-30 g / 10 min.

4. The low-shrinkage, high-gloss polypropylene composition according to any one of claims 1-3, characterized in that, The polyethylene is selected from at least one of high-density polyethylene and linear low-density polyethylene; preferably linear low-density polyethylene. Preferably, the density of the high-density polyethylene is 0.954-0.961 g / cm³. 3 ; and / or, the melt index of the high-density polyethylene at 190°C and 2.16 kg load is 0.7-30 g / 10 min, preferably 5-20 g / 10 min; And / or, the density of the linear low-density polyethylene is 0.920-0.936 g / cm³. 3 ; and / or, the linear low-density polyethylene has a melt index of 1-50 g / 10 min at 190 °C and 2.16 kg load, preferably 5-20 g / 10 min.

5. The low-shrinkage, high-gloss polypropylene composition according to any one of claims 1-4, characterized in that, The adjuvants include nucleating agents and optional antioxidants; Preferably, the nucleating agent includes at least one of sorbitol-based nucleating agents and organophosphate salt nucleating agents.

6. The low-shrinkage, high-gloss polypropylene composition according to claim 5, characterized in that, The adjuvant comprises, by weight, 0.03-0.2 parts of nucleating agent and optionally 0.08-1 parts of antioxidant; preferably, it comprises 0.04-0.08 parts of nucleating agent and 0.1-0.5 parts of antioxidant.

7. The low-shrinkage, high-gloss polypropylene composition according to claim 5 or 6, characterized in that, The antioxidant comprises at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tris[2,4-di-tert-butylphenyl]phosphite, N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine, and 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene; preferably a complex of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris[2,4-di-tert-butylphenyl]phosphite.

8. The method for preparing the low-shrinkage, high-gloss polypropylene composition according to any one of claims 1-7, characterized in that, include: Polypropylene, polyethylene and additives are blended in parts by weight, then melt-extruded and granulated.

9. The preparation method according to claim 8, characterized in that: The blending time is 0.5-5 min, preferably 1-3 min; And / or, the extrusion temperature is 180-250℃, preferably 200-230℃.

10. The application of the low-shrinkage, high-gloss polypropylene composition according to any one of claims 1-7 or the low-shrinkage, high-gloss polypropylene composition prepared by the preparation method according to claim 8 or 9 in the automotive, home appliance and home furnishing fields.

Images