A nucleating agent masterbatch, its preparation method, and its application in low melt index polypropylene materials.

Abstract

This invention discloses a nucleating agent masterbatch, mainly prepared from the following components in parts by weight: 92-96 parts homopolymer polypropylene resin, 1-4 parts nucleating agent A, 1-4 parts nucleating agent B, 0.05-0.1 parts antioxidant, and 0.02-0.08 parts dispersant. This invention also discloses a method for preparing the nucleating agent masterbatch, wherein the above-mentioned homopolymer polypropylene resin, nucleating agent A, nucleating agent B, antioxidant, and dispersant are mixed according to their respective proportions for 10-60 minutes, and then melt-extruded and granulated to obtain the nucleating agent masterbatch; the melt-extruded temperature is 180-220℃. This invention also provides an application of the nucleating agent masterbatch in the preparation of PPB pipes. This invention prepares a masterbatch from nucleating agents and high melt flow index polypropylene resin, and then adds the masterbatch to ultra-low melt flow index PPB pipe resin. Through this modification process, the rigidity of the PPB pipe is significantly improved.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a nucleating agent masterbatch, its preparation method, and its application in low melt index polypropylene materials. Background Technology

[0002] Block copolymer polypropylene (PPB) is produced by copolymerizing polypropylene with another olefin monomer. PPB has a high ethylene content, which improves its low-temperature impact resistance but sacrifices its high-temperature resistance. Therefore, pipes made from PPB are generally suitable for cold water systems.

[0003] Existing PPB pipes also have drawbacks when used in cold water applications, such as insufficient rigidity, resulting in poor pressure resistance and limiting their application. Therefore, research on their modification is particularly important. Among various modification methods, nucleating agent modification is the simplest and most effective. However, even with the addition of nucleating agents, such as phosphates or carboxylates, in the PPB pipe manufacturing process, the improvement in rigidity is extremely limited. This is because, on the one hand, the differences in the crystallization rate and crystallization temperature induced by different nucleating agents lead to incomplete PPB crystallization and a lack of significant rigidity improvement; on the other hand, due to the very low melt flow rate (MFR) of PPB pipes (generally <1 g / 10 min), it is difficult for the nucleating agent to be uniformly dispersed in the PPB resin during the granulation process, making it difficult for the nucleating agent to exert its optimal effect.

[0004] Therefore, there is an urgent need to develop a PPB pipe with good rigidity and strong pressure resistance. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a nucleating agent masterbatch, its preparation method, and its application in low melt flow index polypropylene materials. The proposed nucleating agent masterbatch and its preparation method involve pre-mixing a composite nucleating agent with high melt flow index homopolymer polypropylene resin to form a nucleating agent masterbatch, which is then added to low melt flow index PPB pipe resin. This modification process significantly improves the rigidity of the PPB pipe.

[0006] The technical solution of this invention is implemented as follows:

[0007] A nucleating agent masterbatch is mainly prepared from the following components in parts by weight: 92-96 parts of homopolymer polypropylene resin, 1-4 parts of nucleating agent A, 1-4 parts of nucleating agent B, 0.05-0.1 parts of antioxidant, and 0.02-0.08 parts of dispersant. In this invention, the homopolymer polypropylene resin is referred to as PPH resin.

[0008] In a preferred embodiment of the present invention, a nucleating agent masterbatch is mainly prepared from the following components in parts by weight: 95 parts homopolymer polypropylene resin, 3 parts nucleating agent A, 2 parts nucleating agent B, 0.1 parts antioxidant, and 0.08 parts dispersant.

[0009] The nucleating agent masterbatch described above has a PPH resin with a melt flow rate (MFR) of 75–95 g / 10 min. In this configuration, the PPH resin with an MFR of 75–95 g / 10 min is a high melt flow rate homopolymer polypropylene resin, which, under molten conditions, has a faster flow rate, making it easier to disperse the melt and materials evenly. More preferably, the MFR of the PPH resin is 90 g / 10 min.

[0010] The nucleating agent masterbatch described above has a PPH resin with a flexural modulus of 1500 MPa and a simply supported beam impact strength of 1.5 KJ / m. 2 The load deformation temperature is 95-100℃, and the tensile yield stress is 35.2MPa.

[0011] The nucleating agent masterbatch described above, wherein the nucleating agent A is a phosphate nucleating agent, and the phosphate nucleating agent is selected from one or both of NA-11 and NA-21.

[0012] The nucleating agent masterbatch described above, wherein the nucleating agent B is a carboxylate nucleating agent, and the carboxylate nucleating agent is selected from one or more of aluminum benzoate, bis(p-tert-butylbenzoic acid)hydroxyaluminum, and disodium bicyclo[2.2.1]heptane-2,3-dicarboxylate.

[0013] More preferably, in the nucleating agent masterbatch described above, nucleating agent A is NA-21; and nucleating agent B is bis(p-tert-butylbenzoic acid)aluminum hydroxide. This is because the molecular structure of NA-21 contains Al. 3+ The molecular structure of NA-11 contains Na. + In comparison, NA-21 incorporates more phosphate structures, providing more nucleation sites; while bis(p-tert-butylbenzoic acid)hydroxyaluminum also contains Al 3+ This also provides more carboxylate nucleation sites, since both nucleating agents contain Al in their molecular structure. 3+ This allows the crystallization temperature and crystallization rate of both agents to be at the same level, creating a synergistic effect that promotes the crystallization rate of polypropylene and significantly improves its crystallinity. On the other hand, both nucleating agents contain -OH groups in their molecular structures. As active groups, -OH undergoes a dehydration reaction during melting, allowing the two nucleating agents to promote polypropylene crystallization on one hand and connect polypropylene molecular chain segments on the other. The three form a cross-linked network structure, thereby enabling the polypropylene resin to achieve higher rigidity while improving its impact resistance.

[0014] In the nucleating agent masterbatch described above, the dispersant is an anionic dispersant or a nonionic dispersant.

[0015] The nucleating agent masterbatch described above, wherein the dispersant is selected from one or more of sodium dodecyl sulfate, sodium octadecyl sulfate, sodium dodecylbenzene sulfonate, sodium hexadecylbenzene sulfonate, sodium octadecylbenzene sulfonate, fatty alcohol polyoxyethylene ether, or sorbitol fatty acid polyoxyethylene ether. Preferably, the dispersant is selected from sodium octadecylbenzene sulfonate or sorbitol fatty acid polyoxyethylene ether. More preferably, the dispersant is selected from sorbitol fatty acid polyoxyethylene ether, which is a small molecule surfactant that does not ionize when dissolved in water, exhibits neither positive nor negative charge, and whose polyhydroxy groups can uniformly mix the hydrophobic PPH resin and the two nucleating agents, improving the dispersion degree of the two nucleating agents in the PPH resin molecular chain segments, thereby improving the crystallinity of polypropylene and significantly improving the rigidity of the product.

[0016] The nucleating agent masterbatch described above is characterized in that the antioxidant is selected from one or more of antioxidants 1010, 1076, 2246, 168, 622, 944, 3114, 626, and 618. Preferably, the antioxidant is selected from one or two of antioxidants 1010 and 168.

[0017] Based on the same inventive concept, the present invention also provides a method for preparing nucleating agent masterbatch, wherein the above-mentioned PPH resin, nucleating agent A, nucleating agent B, antioxidant and dispersant are mixed in their respective proportions for 10 to 60 minutes, and then melt-extruded and granulated to obtain nucleating agent masterbatch; the melt extrusion temperature is 180 to 220°C.

[0018] Based on the same inventive concept, this invention also provides the application of the nucleating agent masterbatch described above in the preparation of PPB pipes. The method for preparing PPB pipes according to this invention includes the following steps: taking 1000 parts of low melt index polypropylene resin, 1-2 parts of antioxidant 330, 0.5-1 parts of lubricant, and 40-50 parts of the nucleating agent masterbatch described above, mixing the above raw materials in a high-speed mixer for 10-20 minutes, extruding and granulating the mixture through an extruder to obtain modified PPB resin particles; then extruding the mixture again to obtain PPB pipes. The extruder temperature for granulation is between 260-280°C; the extruder temperature for pipe extrusion is between 200-230°C. Preferably, the MFR of the low melt index polypropylene resin is 0.5 g / 10 min.

[0019] Preferably, 1000 parts of PPB resin, 1 part of antioxidant 330, 0.5 parts of lubricant, and 40 parts of the nucleating agent masterbatch as described above are taken respectively. The above raw materials are placed in a high-speed mixer and mixed for 10 minutes. The mixture is then extruded and granulated through an extruder to obtain modified PPB resin granules. These granules are then extruded again to obtain PPB pipes. Preferably, the extruder temperature for granulation is 280°C; the extruder temperature for pipe extrusion is 220°C.

[0020] In this invention, two nucleating agents and high melt flow index (MFR) PPH resin are pre-prepared into a nucleating agent masterbatch. This masterbatch is then added to a low melt flow index (MFR) PPB resin. In this invention, the low melt flow index (MFR) PPB resin refers to a PPB resin with an MFR of 0–1 g / 10 min. The modification process significantly improves the rigidity of the PPB resin. The reason for this significant improvement in PPB resin rigidity is that after pre-preparing the nucleating agent masterbatch with the two nucleating agents and high melt flow index PPH resin, the high crystallinity of the PPH resin and the extremely high nucleating agent content in the masterbatch provide numerous nucleation sites, inducing rapid crystallization of the PPH resin in a shorter time, resulting in a significant increase in crystallinity. Furthermore, the high melt flow index (MFR) PPB resin used in this invention... PPH resin has excellent flowability. When preparing nucleating agent masterbatch, high-concentration nucleating agents can be uniformly dispersed in PPH resin. Due to the synergistic nucleation effect of the two nucleating agents, a large number of crystal nuclei are uniformly and finely dispersed in the PPH resin system. The prepared nucleating agent masterbatch is then added to low melt index PPB resin, which is equivalent to pre-dispersing the two nucleating agents in PPH resin and then adding them to PPB resin for secondary dispersion. The role of high melt index PPH resin is to act as a dispersion carrier for the two nucleating agents in PPB resin, so that the two nucleating agents are more uniformly dispersed in PPB resin, the nucleation sites are more uniform, and the crystallinity of PPB is higher. Ultimately, it can significantly improve the rigidity of PPB resin material and improve its mechanical properties.

[0021] Secondly, nucleating agent masterbatch made from PPH resin allows the two nucleating agents to rapidly crystallize and form small, uniform crystal nuclei in the PPH resin. When these nucleating agents are added to PPB resin for modification, the small, uniform crystal nuclei quickly move and distribute into the molecular chain segments of the PPB resin, thereby increasing the crystallization rate and crystallinity of the PPB resin. Furthermore, since the crystal nuclei of the two nucleating agents are uniformly dispersed in the molecular chain segments of the PPB resin, the entanglement of the original molecular chain segments of the PPB resin is not affected, and the impact resistance of the PPB resin material is not reduced.

[0022] The applicant also discovered that if these two nucleating agents were not pre-prepared into nucleating agent masterbatches and were instead added directly to PPB resin, the improvement in the rigidity of the PPB resin material was not significant. This is because the melt flow rate (MFR) of the PPB resin used in PPB pipe production is very low, only 0.5 g / 10 min. The melt flow rate in the extruder is very slow, and the residence time of the PPB resin in the extruder is short. Even with the addition of dispersants, the nucleating agents cannot be quickly and uniformly dispersed into the PPB resin in a short time. Furthermore, since the two nucleating agents are added directly to the PPB resin, the flow rate of the nucleating agents in the extruder differs from that of the low melt flow rate PPB resin, resulting in uneven dispersion of the nucleating agents in the PPB resin. This can easily lead to high nucleating agent content in some PPB resins, resulting in different degrees of crystallization between the two phases and potentially causing phase separation. This, in turn, reduces the mechanical properties of the PPB resin material, directly affecting product quality.

[0023] The beneficial effects of this invention are:

[0024] 1. This invention provides a nucleating agent masterbatch, mainly prepared from the following components in parts by weight: 92-96 parts of PPH resin, 1-4 parts of nucleating agent A, 1-4 parts of nucleating agent B, 0.05-0.1 parts of antioxidant, and 0.02-0.08 parts of dispersant. The PPH resin used is a high melt flow index PPH resin with an MFR of 75-95 g / 10 min. Using the high melt flow index PPH resin as a carrier for the two nucleating agents makes the nucleating agents more uniformly dispersed in the low melt flow index PPB resin system, ultimately improving the rigidity of the PPB resin material. Nucleating agents A and B rapidly crystallize and nucleate in the high melt flow index PPH resin, improving the crystallization rate and crystallinity of the PPB resin material when modifying the PPB resin.

[0025] 2. During the research on the modification of PPB resin, the applicant unexpectedly discovered that by using high melt index PPH resin to prepare nucleating agent masterbatch in advance and then using it in the modification process of low melt index PPB resin pipes, the rigidity of PPB pipes can be greatly improved while ensuring that their toughness is not affected.

[0026] 3. The test results of this invention show that the PPB pipe prepared by this invention has a crystallinity of 67.7% to 71.8%, high rigidity, good pressure resistance, and no leakage or cracking under long-term hydrostatic pressure. At the same time, the mechanical properties of the pipe, such as tensile strength, elongation at break and impact strength of simply supported beam, are significantly improved. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0029] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0030] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0031] The high melt flow index (MFR) PPH resin was purchased from Hengli Petrochemical Co., Ltd., grade PPH-MM90, MFR = 90 g / 10 min; the medium melt flow index (MFR) PPH resin was purchased from Zhejiang Hongji Petrochemical Co., Ltd., grade 225, MFR = 25 g / 10 min; the low melt flow index (MFR) PPB resin was purchased from Beijing Yanshan Petrochemical Co., Ltd., grade B8101, MFR = 0.5 g / 10 min; the lubricant PPA was purchased from Shanghai Qirun New Materials Co., Ltd., grade PPA-926; the phosphate nucleating agent NA-21 was purchased from Shanghai Qirun New Materials Co., Ltd.; the bis(p-tert-butylbenzoic acid) hydroxyaluminum was purchased from Shanghai Qirun New Materials Co., Ltd.; the antioxidant 330 was purchased from Shanghai Qirun New Materials Co., Ltd.; other raw materials were commercially available and had no specific requirements.

[0032] Example 1:

[0033] The nucleating agent masterbatch provided in this embodiment is mainly prepared from the following raw materials in parts by weight:

[0034] PPH-MM90 resin, 95 parts;

[0035] Nucleating agent A is NA-21, 3 parts;

[0036] Nucleating agent B is bis(p-tert-butylbenzoic acid)aluminum hydroxide, 2 parts;

[0037] Antioxidant 1010, 0.1 parts;

[0038] Sorbitol fatty acid polyoxyethylene ether, 0.08 parts.

[0039] This embodiment provides a nucleating agent masterbatch, which is prepared by the following method, specifically including the following steps:

[0040] The above masterbatch formulations were mixed in a high-speed mixer for 10 minutes according to their respective proportions. The maximum temperature of the twin-screw extruder barrel was set to 210℃, the main machine speed was 400r / min, and the feeding speed was 35r / min. The mixture was then extruded and granulated by a twin-screw extruder to obtain the nucleating agent masterbatch.

[0041] The PPB pipe provided in this embodiment is prepared by the following method:

[0042] 1000g of B8101 resin, 1g of antioxidant 330, 0.5g of lubricant PPA-926, and 40g of the nucleating agent masterbatch prepared above were taken and mixed in a high-speed mixer for 10 minutes. The mixture was then extruded and granulated to obtain modified B8101 resin particles. These particles were then extruded again to obtain the PPB pipe of this embodiment. The extruder temperature for granulation was 280℃, and the extruder temperature for pipe extrusion was 220℃.

[0043] Example 2:

[0044] The only difference from Example 1 is that nucleating agent A is NA-21, 2 parts; nucleating agent B is bis(p-tert-butylbenzoic acid)hydroxyaluminum, 3 parts; the rest is the same as in Example 1.

[0045] Example 3:

[0046] The only difference from Example 1 is that nucleating agent A is NA-21, 4 parts; nucleating agent B is bis(p-tert-butylbenzoic acid)hydroxyaluminum, 1 part; the rest is the same as in Example 1.

[0047] Example 4:

[0048] The only difference from Example 1 is that nucleating agent A is NA-11, 3 parts; nucleating agent B is bis(p-tert-butylbenzoic acid)hydroxyaluminum, 2 parts; the rest is the same as in Example 1.

[0049] Example 5:

[0050] The only difference from Example 1 is that nucleating agent A is NA-11, 3 parts; nucleating agent B is aluminum benzoate, 2 parts; the rest is the same as in Example 1.

[0051] Example 6:

[0052] The only difference from Example 1 is that nucleating agent A is NA-11, 3 parts; nucleating agent B is bicyclo[2.2.1]heptane-2,3-dicarboxylic acid disodium salt, 2 parts; the rest is the same as in Example 1.

[0053] Example 7:

[0054] The only difference from Example 1 is that: 0.1 parts of a 1:1 mixture of antioxidant 1010 and antioxidant 168; 0.05 parts of sorbitol fatty acid polyoxyethylene ether; the rest are the same as in Example 1.

[0055] Example 8:

[0056] The only difference from Example 1 is that: 0.1 parts of a 1:1 mixture of antioxidant 1010 and antioxidant 168; 0.08 parts of sodium octadecylbenzenesulfonate; the rest are the same as in Example 1.

[0057] Comparative Example 1:

[0058] The only difference from Example 1 is that the PPH resin used is a medium melt index PPH resin, grade 225, 95 parts; the rest is the same as in Example 1.

[0059] Comparative Example 2:

[0060] 1000g of B8101 resin, 1g of antioxidant 330, and 0.5g of lubricant PPA were taken separately, without adding nucleating agent. The above raw materials were placed in a high-speed mixer and mixed for 10 minutes. The mixture was then extruded and granulated to obtain modified B8101 resin granules. These granules were then extruded again to obtain the PPB pipe of this comparative example. The extruder temperature for granulation was 280℃; the extruder temperature for pipe extrusion was 220℃.

[0061] Comparative Example 3:

[0062] Take 95 parts of PPH-MM90 resin, 3 parts of NA-21, 2 parts of bis(p-tert-butylbenzoic acid) aluminum hydroxide, 0.1 parts of antioxidant 1010, and 0.08 parts of sorbitol fatty acid polyoxyethylene ether, mix them evenly, do not granulate, and set aside.

[0063] 1000g of B8101 resin, 1g of antioxidant 330, 0.5g of lubricant PPA, and 40g of the uniformly mixed, ungranulated nucleating agent masterbatch powder were taken. These raw materials were mixed in a high-speed mixer for 10 minutes, then extruded and granulated to obtain modified B8101 resin granules. These granules were then extruded again to obtain the PPB pipe of this comparative example. The extruder temperature for granulation was 280℃; the extruder temperature for pipe extrusion was 220℃.

[0064] Samples of the PPB pipes prepared in Examples 1-8 and the pipes prepared in Comparative Examples 1-3 were prepared and tested. The results are shown in Table 1.

[0065] Test according to the following standards:

[0066] The flexural modulus was tested according to GB / T 9341 standard;

[0067] The impact strength of simply supported beams was tested in accordance with GB / T 1043 standard;

[0068] Tensile strength and elongation at break were tested in accordance with GB / T 8804 standard;

[0069] The hydrostatic strength was tested according to GB / T 6111 standard;

[0070] Crystallinity: The sample was tested by differential scanning calorimetry (DSC). The temperature was increased to 200℃ at a rate of 10℃ / min, held for 5 min, and then cooled to room temperature at a rate of 10℃ / min. The crystallinity was calculated from the obtained DSC curve.

[0071] Table 1. Performance test results of the pipes prepared in Examples 1-8 and Comparative Examples 1-2 of the present invention.

[0072]

[0073]

[0074] (Note: NB in ​​the table represents no breakage)

[0075] As shown in Table 1 of this invention, the crystallinity of the PPB pipes prepared in Examples 1-8 of this invention ranges from 67.7% to 71.8%, which is significantly higher than that of Comparative Examples 1-3. This indicates that the nucleating agent masterbatch prepared in this invention significantly improves the crystallinity of PPB resin when applied to low melt flow index PPB resin, thereby significantly improving the mechanical properties of the PPB resin material. Comparing the results of Example 1 and Comparative Example 3, under the same amount of nucleating agent added, if the two nucleating agents are not pre-prepared into nucleating agent masterbatch and are used directly in combination, Comparative Example 3 only slightly improves the crystallinity of low melt flow index PPB resin, and the improvement in mechanical properties is not significant. The hydrostatic strength test shows that the pipes prepared in Examples 1-8 of this invention have no leakage or cracking, indicating that the pipes prepared in this invention have good rigidity and excellent pressure resistance.

[0076] Comparative Example 1 uses a medium melt index PPH resin, which has poorer fluidity under molten conditions than the high melt index PPH resin of this invention. Therefore, the dispersibility of the nucleating agent in the medium melt index resin system is not as good as in the high melt index resin system. Consequently, the nucleating agent masterbatch prepared in Comparative Example 1 has a relatively poor performance improvement effect when applied to PPB resin. Comparative Example 2 does not add a nucleating agent, and its crystallinity, pipe flexural modulus, tensile strength, elongation at break, and simply supported beam impact strength are all poor. The hydrostatic strength test results of the pipe do not meet the standards.

[0077] Therefore, this invention prepares nucleating agent masterbatch by selecting suitable homopolymer polypropylene resin, nucleating agent, antioxidant, and dispersant. While maintaining optimal rigidity and compressive strength, the addition ratio of the nucleating agent masterbatch and the combination of each component achieve an optimal balance in flexural modulus, tensile strength, elongation at break, simply supported beam impact strength, and hydrostatic strength. In other words, the high melt flow index homopolymer polypropylene resin, nucleating agent, antioxidant, and dispersant components used in preparing the nucleating agent masterbatch in this invention must be used in combination. Similarly, the low melt flow index PPB resin, antioxidant, lubricant, and dedicated nucleating agent masterbatch used in preparing the pipes in this invention must be used in combination to achieve the overall comprehensive performance of the material. Furthermore, replacing similar components, omitting the nucleating agent component, or changing the nucleating agent preparation process will not achieve the superior effects of this invention.

[0078] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. The application of a nucleating agent masterbatch in the preparation of PPB pipes, characterized in that, Take 1000 parts of low melt flow index polypropylene resin, 1-2 parts of antioxidant, 0.5-1 parts of lubricant, and 40-50 parts of nucleating agent masterbatch. Mix the above raw materials in a high-speed mixer for 10-20 minutes, and then granulate them by extrusion to obtain modified PPB resin granules. Then, extrude them again to obtain PPB pipes. The MFR of the low melt flow index polypropylene resin is 0.5-1 g / 10 min. Nucleating agent masterbatch is prepared in advance using homopolymer polypropylene resin; the nucleating agent masterbatch is mainly prepared from the following components in parts by weight: 92-96 parts homopolymer polypropylene resin, 1-4 parts nucleating agent A, 1-4 parts nucleating agent B, 0.05-0.1 parts antioxidant, and 0.02-0.08 parts dispersant; the MFR of the homopolymer polypropylene resin is 75-95 g / 10 min; the dispersant is selected from sorbitol fatty acid polyoxyethylene ether; the nucleating agent A is NA-21; and the nucleating agent B is bis(p-tert-butylbenzoic acid) hydroxyaluminum.

2. The application of the nucleating agent masterbatch according to claim 1 in the preparation of PPB pipes, characterized in that, The low melt flow index (MFR) of the polypropylene resin is 0.5 g / 10 min.

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