Highlight polypropylene composite material with excellent surface appearance and preparation method thereof

Abstract

The invention discloses a highlight polypropylene composite material with excellent surface appearance and a preparation method thereof. The composite material is prepared from the following components in parts by weight: 47-78.6 parts of polypropylene, 20-50 parts of barium sulfate, 1-2 parts of a dressing polymeric dispersant, 0.2-0.6 part of an antioxidant and 0.2-0.4 part of a light stabilizer. The prepared dressing polymeric dispersant has a special comb-shaped structure, so that the dressing polymeric dispersant has relatively large steric hindrance, the relatively large steric hindrance can prevent self-agglomeration, and barium sulfate is helped to have better dispersity; and the dispersant has amide groups with relatively large polarity, so that the dispersant has relatively large surface polarity and can help to adsorb a barium sulfate material, counteract agglomeration force in the barium sulfate material and promote dispersion of barium sulfate. The stable barium sulfate dispersion effect can be obtained under the condition of small addition amount of the dressing polymeric dispersant, and the high-gloss polypropylene material with excellent surface appearance is obtained.

Description

Technical Field

[0001] The present invention belongs to the field of polymer materials, and particularly relates to a high-gloss polypropylene composite material with excellent surface appearance and a preparation method thereof. Background Art

[0002] Due to its excellent mechanical properties and low price, polypropylene materials are widely used in household appliances, electronic and electrical products. In recent years, with the improvement of people's living standards, various smart home appliances have been widely used, such as the sales volume of small household appliances such as ovens and smart toilets has increased significantly. These household appliances need to have very good appearance. Generally, high-gloss PP is used as the raw material for injection molding parts, that is, barium sulfate-filled modified polypropylene is used as the raw material. However, surface pitting is a common problem of barium sulfate-filled PP materials, which is difficult to improve. And during mass production, it is very easy to have poor injection molding pitting due to changes in the twin-screw extruder process, and it is difficult to detect during the twin-screw blending extrusion process of the modified material. Often, a large number of unqualified products are caused by poor pitting during injection molding, increasing costs and causing waste of raw materials. Summary of the Invention

[0003] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a high-gloss polypropylene composite material with excellent surface appearance and a preparation method thereof. The present invention prepares a comb-shaped polymer material as a dispersant, which has a very good effect of dispersing barium sulfate, and can prepare a barium sulfate-filled high-gloss polypropylene material with very good surface state.

[0004] The purpose of the present invention is achieved by the following technical solutions:

[0005] A high-gloss polypropylene composite material with excellent surface appearance is prepared from the following components by weight: 47 - 78.6 parts of polypropylene, 20 - 50 parts of barium sulfate, 1 - 2 parts of comb-shaped polymer dispersant, 0.2 - 0.6 parts of antioxidant, and 0.2 - 0.4 parts of light stabilizer;

[0006] The preparation method of the comb-shaped polymer dispersant is as follows:

[0007] (1) Phthalic anhydride and methoxypolyethylene glycol are added to a long-necked flask in a molar ratio of 1:0.8 - 1.2, and then 4-dimethylaminopyridine is added as a catalyst (the molar ratio of phthalic anhydride to 4-dimethylaminopyridine is 1:0.05 - 0.2). Under the protection of nitrogen, it is heated to 120°C - 125°C and reacted for 2 - 4 hours. The reaction product is dissolved in acetone and reprecipitated in methanol, and vacuum dried at 30 - 50°C to obtain phthalic acid methoxypolyethylene glycol ester with the following molecular formula;

[0008]

[0009] (2) Add styrene and acrylic acid to a single-necked flask in a molar ratio of 8:1 - 3, and select benzoyl peroxide as the initiator. Under the protection of nitrogen, react the single-necked flask at 100 - 120 °C for 1 - 3 hours. Dissolve the reaction product in acetone and reprecipitate it in methanol. Filter the obtained solid product and dry it under vacuum at 60 - 80 °C to obtain a polymerization product with the molecular formula shown below;

[0010]

[0011] (3) Dissolve the isatoic anhydride polyethylene glycol monomethyl ether ester prepared in step (1) and the polymerization product prepared in step (2) in a solvent in a molar ratio of 1:0.8 - 1.2, pour it into a long-necked flask, add 2-bromophenylboronic acid as a catalyst (where the molar ratio of isatoic anhydride polyethylene glycol monomethyl ether ester to 2-bromophenylboronic acid is 1:0.05 - 0.5), react at 80 °C - 95 °C for 6 - 12 hours, separate the obtained precipitate, and dry it under vacuum at 60 °C - 80 °C to obtain a dressing polymer dispersant. The involved reaction equations are as follows:

[0012]

[0013] In a further aspect, the antioxidant is at least one of histamine-based antioxidants, hindered phenol-based antioxidants, and phosphite-based antioxidants.

[0014] In a further aspect, the light stabilizer is a histamine-based light stabilizer.

[0015] The present invention also discloses a method for preparing the high-gloss polypropylene composite material with excellent surface appearance as described above, including the following steps:

[0016] Add polypropylene, barium sulfate, dressing polymer dispersant, antioxidant, and light stabilizer to a high-speed mixer according to the weight ratio. After dry mixing at 60 °C - 90 °C for 5 - 15 minutes, add the uniform mixed material to a twin-screw extruder for melt extrusion and pelletization to obtain the target product. Preferably, the temperatures of each zone of the twin-screw extruder are as follows: the temperature of the first zone is 170 - 180 °C, the temperature of the second zone is 170 - 190 °C, the temperature of the third zone is 180 - 200 °C, the temperature of the fourth zone is 190 - 210 °C, and the temperature of the fifth zone is 190 - 220 °C.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] The comb-shaped polymer dispersant prepared by the present invention has a special comb-shaped structure, which gives it a large steric hindrance. The large steric hindrance itself can prevent self-aggregation and help barium sulfate have a better dispersion degree. Moreover, the dispersant has an amide group with a relatively large polarity, which gives it a relatively large surface polarity, can help adsorb barium sulfate materials, offset the aggregation force inside the barium sulfate materials, and promote the dispersion of barium sulfate. The comb-shaped polymer dispersant used in the present invention can obtain a stable dispersion effect of barium sulfate under a relatively small addition amount, and can prepare a high-gloss polypropylene material with excellent surface appearance. Detailed Embodiments

[0019] The following further illustrates the present invention with reference to embodiments, so that those skilled in the art can better understand the present invention and be able to implement it, but the exemplified embodiments do not limit the present invention.

[0020] In addition, in the preparation processes of the following embodiments, unless otherwise specified, they are all conventional means in the prior art in this field. Therefore, they will not be described in detail; the parts in the following embodiments all refer to parts by weight.

[0021] The models and suppliers of the reagents used in this embodiment are as follows:

[0022] The polypropylene grade is PP BX3800, purchased from SK Chemicals, South Korea;

[0023] Polyethylene glycol monomethyl ether is of analytical grade, purchased from Sigma-Aldrich;

[0024] The above reagents are only for explaining the reagent sources and components used in the experiments of the present invention for full disclosure, and do not mean that the present invention cannot be achieved by using other similar reagents or reagents provided by other suppliers.

[0025] Example 1

[0026] According to parts by weight, 67.8 parts of polypropylene, 30 parts of barium sulfate, 1.5 parts of the comb-shaped polymer dispersant, 0.2 part of antioxidant 1010, 0.2 part of antioxidant 168, and 0.3 part of light stabilizer V703 are added to a high-speed mixer and dry-mixed at 70 °C for 10 min. Then, the uniform mixed material is added to a twin-screw extruder for melt extrusion and pelletization. The temperature of the first zone of the twin-screw extruder is 175 °C, the second zone is 180 °C, the third zone is 190 °C, the fourth zone is 200 °C; the fifth zone is 210 °C to obtain a high-gloss polypropylene material.

[0027] The preparation method of the comb-shaped polymer dispersant is as follows:

[0028] (1) Add isatoic anhydride and methoxypolyethylene glycol in a molar ratio of 1:1 to a long-necked flask, then add 4-dimethylaminopyridine as a catalyst (the molar ratio of isatoic anhydride to 4-dimethylaminopyridine is 1:0.1). Under the protection of nitrogen, heat to 122 °C and react for 3 hours. Dissolve the reactants in acetone and reprecipitate in methanol, and then dry under vacuum at 40 °C to obtain methoxypolyethylene glycol isatoate;

[0029] (2) Add styrene and acrylic acid in a molar ratio of 8:2 to a single-necked flask, and select benzoyl peroxide as an initiator. Under the protection of nitrogen, react the single-necked flask at 110 °C for 2 hours. Dissolve the reactants in acetone and reprecipitate in methanol, and filter the obtained solid product and dry it under vacuum at 70 °C to obtain a polymerization product;

[0030] (3) Dissolve the methoxypolyethylene glycol isatoate prepared in step (1) and the polymerization product prepared in step (2) in DMF in a molar ratio of 1:1 and pour them into a long-necked flask. Add 2-bromophenylboronic acid as a catalyst (the molar ratio of reactant A to 2-bromophenylboronic acid is 1:0.3). React at 85 °C for 10 hours, filter the precipitate, and dry it under vacuum at 70 °C to obtain a dressing polymer dispersant.

[0031] Example 2

[0032] According to the weight ratio, add 58 parts of polypropylene, 40 parts of barium sulfate, 1.2 parts of dressing polymer dispersant, 0.2 parts of antioxidant 1010, 0.3 parts of antioxidant 1076, and 0.3 parts of light stabilizer 5589 to a high-speed mixer and dry-mix at 80 °C for 12 min. Then add the uniform mixed material to a twin-screw extruder for melt extrusion and pelletization. The temperature of the first zone of the twin-screw extruder is 175 °C, the second zone is 185 °C, the third zone is 195 °C, the fourth zone is 200 °C, and the fifth zone is 210 °C to obtain a high-gloss polypropylene material.

[0033] The preparation method of the dressing polymer dispersant is as follows:

[0034] (1) Add isatoic anhydride and methoxypolyethylene glycol in a molar ratio of 1:0.9 to a long-necked flask, then add 4-dimethylaminopyridine as a catalyst (the molar ratio of isatoic anhydride to 4-dimethylaminopyridine is 1:0.1). Under the protection of nitrogen, heat to 120 °C and react for 3 hours. Dissolve the reactants in acetone and reprecipitate in methanol, and then dry under vacuum at 35 °C to obtain methoxypolyethylene glycol isatoate;

[0035] (2) Add styrene and acrylic acid in a molar ratio of 8:1.5 to a single-necked flask, and select benzoyl peroxide as the initiator. Under the protection of nitrogen, react the single-necked flask at 115 °C for 2.5 hours. Dissolve the reactants in acetone and reprecipitate them in methanol. Filter the obtained solid product and dry it in vacuo at 75 °C to obtain the polymerization product;

[0036] (3) Dissolve the isatoic anhydride polyethylene glycol monomethyl ether ester prepared in step (1) and the polymerization product prepared in step (2) in a molar ratio of 1:0.9 in DMF and pour it into a long-necked flask. Add 2-bromophenylboronic acid as a catalyst (the molar ratio of reactant A to 2-bromophenylboronic acid is 1:0.3), react at 92 °C for 8 hours, filter the precipitate, and dry it in vacuo at 65 °C to obtain the dressing polymer dispersant.

[0037] Example 3

[0038] According to the weight ratio, add 62.6 parts of polypropylene, 35 parts of barium sulfate, 1.8 parts of the dressing polymer dispersant, 0.3 part of antioxidant 168, and 0.3 part of light stabilizer V703 to a high-speed mixer and dry mix at 85 °C for 12 min. Then add the uniform mixed material to a twin-screw extruder for melt extrusion and pelletization. The temperature of the first zone of the twin-screw extruder is 175 °C, the second zone is 185 °C, the third zone is 190 °C, the fourth zone is 200 °C, and the fifth zone is 200 °C to obtain a high-gloss polypropylene material.

[0039] The preparation method of the dressing polymer dispersant is as follows:

[0040] (1) Add isatoic anhydride and polyethylene glycol monomethyl ether to a long-necked flask in a molar ratio of 1:0.9, and then add 4-dimethylaminopyridine as a catalyst (the molar ratio of isatoic anhydride to 4-dimethylaminopyridine is 1:0.13). Under the protection of nitrogen, heat to 120 °C and react for 3 hours. Dissolve the reactants in acetone and reprecipitate them in methanol. Dry in vacuo at 45 °C to obtain isatoic anhydride polyethylene glycol monomethyl ether ester;

[0041] (2) Add styrene and acrylic acid in a molar ratio of 8:2 to a single-necked flask, and select benzoyl peroxide as the initiator. Under the protection of nitrogen, react the single-necked flask at 115 °C for 2 hours. Dissolve the reactants in acetone and reprecipitate them in methanol. Filter the obtained solid product and dry it in vacuo at 80 °C to obtain the polymerization product;

[0042] (3) Dissolve the isatoic anhydride polyethylene glycol monomethyl ether ester prepared in step (1) and the polymerization product prepared in step (2) in DMF according to a molar ratio of 1:1, pour them into a long-necked flask, add 2-bromophenylboronic acid as a catalyst (where the molar ratio of reactant A to 2-bromophenylboronic acid is 1:0.4), react at 90 °C for 10 hours, filter the precipitate, and dry it under vacuum at 70 °C to obtain a dressing polymer dispersant.

[0043] Example 4

[0044] According to the weight ratio, add 78.6 parts of polypropylene, 20 parts of barium sulfate, 1 part of the dressing polymer dispersant, 0.2 parts of antioxidant 1010, and 0.2 parts of light stabilizer 5589 to a high-speed mixer, dry-mix at 60 °C for 5 minutes, and then add the uniform mixed material to a twin-screw extruder for melt extrusion and pelletization. The temperature of the first zone of the twin-screw extruder is 170 °C, the second zone is 170 °C, the third zone is 180 °C, the fourth zone is 190 °C, and the fifth zone is 190 °C to obtain a high-gloss polypropylene material.

[0045] The preparation method of the dressing polymer dispersant is as follows:

[0046] (1) Add isatoic anhydride and polyethylene glycol monomethyl ether to a long-necked flask according to a molar ratio of 1:0.8, then add 4-dimethylaminopyridine as a catalyst (the molar ratio of isatoic anhydride to 4-dimethylaminopyridine is 1:0.05), heat to 120 °C under the protection of nitrogen, react for 2 hours, dissolve the reactant in acetone and reprecipitate it in methanol, and dry it under vacuum at 30 °C to obtain isatoic anhydride polyethylene glycol monomethyl ether ester;

[0047] (2) Add styrene and acrylic acid to a single-necked flask according to a molar ratio of 8:1, and select benzoyl peroxide as an initiator. Under the protection of nitrogen, react the single-necked flask at 100 °C for 1 hour, dissolve the reactant in acetone and reprecipitate it in methanol, and vacuum-dry the filtered solid product at 60 °C to obtain a polymerization product;

[0048] (3) Dissolve the isatoic anhydride polyethylene glycol monomethyl ether ester prepared in step (1) and the polymerization product prepared in step (2) in DMF according to a molar ratio of 1:0.8, pour them into a long-necked flask, add 2-bromophenylboronic acid as a catalyst (where the molar ratio of reactant A to 2-bromophenylboronic acid is 1:0.05), react at 80 °C for 6 hours, filter the precipitate, and dry it under vacuum at 60 °C to obtain a dressing polymer dispersant.

[0049] Example 5

[0050] Mix 47 parts by weight of polypropylene, 50 parts of barium sulfate, 2 parts of a dressing polymer dispersant, 0.3 part of antioxidant 1010, 0.3 part of antioxidant 168, and 0.4 part of light stabilizer 586 in a high-speed mixer and dry-mix at 90 °C for 15 min. Then add the uniform mixed material to a twin-screw extruder for melt extrusion and pelletization. The temperature of the first zone of the twin-screw extruder is 180 °C, the second zone is 190 °C, the third zone is 200 °C, the fourth zone is 210 °C, and the fifth zone is 220 °C to obtain a high-gloss polypropylene material.

[0051] The preparation method of the dressing polymer dispersant is as follows:

[0052] (1) Add isatoic anhydride and methoxypolyethylene glycol in a molar ratio of 1:1.2 to a long-necked flask, and then add 4-dimethylaminopyridine as a catalyst (the molar ratio of isatoic anhydride to 4-dimethylaminopyridine is 1:0.2). Under the protection of nitrogen, heat to 125 °C and react for 4 hours. Dissolve the reactant in acetone and reprecipitate in methanol, and dry under vacuum at 50 °C to obtain isatoic acid methoxypolyethylene glycol ester;

[0053] (2) Add styrene and acrylic acid in a molar ratio of 8:3 to a single-necked flask, and select benzoyl peroxide as an initiator. Under the protection of nitrogen, react the single-necked flask at 120 °C for 3 hours. Dissolve the reactant in acetone and reprecipitate in methanol, and vacuum-dry the filtered solid product at 80 °C to obtain a polymerization product;

[0054] (3) Dissolve the isatoic acid methoxypolyethylene glycol ester prepared in step (1) and the polymerization product prepared in step (2) in a molar ratio of 1:1.2 in DMF and pour it into a long-necked flask. Add 2-bromophenylboronic acid as a catalyst (the molar ratio of reactant A to 2-bromophenylboronic acid is 1:0.5), and react at 95 °C for 12 hours. Filter the precipitate and dry it under vacuum at 80 °C to obtain the dressing polymer dispersant.

[0055] Comparative Example 1:

[0056] Mix 67.8 parts by weight of polypropylene, 30 parts of barium sulfate, 1.5 parts of silicone-based dispersant E525, 0.2 part of antioxidant 1010, 0.2 part of antioxidant 168, and 0.3 part of light stabilizer V703 in a high-speed mixer and dry-mix at 70 °C for 10 min. Then add the uniform mixed material to a twin-screw extruder for melt extrusion and pelletization. The temperature of the first zone of the twin-screw extruder is 175 °C, the second zone is 180 °C, the third zone is 190 °C, the fourth zone is 200 °C, and the fifth zone is 210 °C to obtain a high-gloss polypropylene material.

[0057] Comparative Example 2:

[0058] 64.3 parts of polypropylene, 30 parts of barium sulfate, 5 parts of silicone dispersant E525, 0.2 part of antioxidant 1010, 0.2 part of antioxidant 168, and 0.3 part of light stabilizer V703 were dry-mixed in a high-speed mixer at 70 °C for 10 min according to parts by weight. Then, the uniform mixed material was added to a twin-screw extruder for melt extrusion and pelletization. The temperature of the first zone of the twin-screw extruder was 175 °C, the second zone was 180 °C, the third zone was 190 °C, the fourth zone was 200 °C, and the fifth zone was 210 °C, to obtain a high-gloss polypropylene material.

[0059] Result test:

[0060] Samples were prepared on a high-gloss mold with dimensions of 5 cm * 5 cm from the polypropylene materials prepared in Examples 1-5 and Comparative Examples 1-2. The surface pitting was visually observed. Pitting with a size diameter of 0.05 mm - 0.25 mm was counted as one pitting. Five samples of each type were taken as a group, and the total number of pittings in each group was calculated (if any one of the five samples had pitting with a size diameter greater than 0.25 mm, the pitting effect of the group was directly determined to be unqualified). The results are shown in Table 1 below:

[0061] Table 1

[0062]

[0063] It can be seen from Table 1 that the polymer dispersant for dressing prepared by the present invention can have excellent barium sulfate dispersion effect at a relatively low addition ratio, and is suitable for preparing polypropylene modified materials with extremely high surface property requirements.

[0064] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0065] The above-described embodiments merely represent several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A high-gloss polypropylene composite material with excellent surface appearance, characterized in that: it is prepared from the following components in parts by weight: 47 - 78.6 parts of polypropylene, 20 - 50 parts of barium sulfate, 1 - 2 parts of dressing polymer dispersant, 0.2 - 0.6 parts of antioxidant, 0.2 - 0.4 parts of light stabilizer; The preparation method of the dressing polymer dispersant is as follows: Isatoic anhydride and methoxypolyethylene glycol are subjected to an esterification reaction to obtain isatoic acid methoxypolyethylene glycol monoester; Styrene and acrylic acid are subjected to a polymerization reaction in the presence of an initiator to obtain a polymerization product; Isatoic acid methoxypolyethylene glycol monoester and the polymerization product are dissolved in a solvent according to a molar ratio of 1:0.8 - 1.2, and 2-bromophenylboronic acid is used as a catalyst, and the reaction is carried out at 80°C - 95°C for 6 - 12 hours. The obtained precipitate is separated and dried to obtain the dressing polymer dispersant.

2. The high-gloss polypropylene composite material with excellent surface appearance according to claim 1, characterized in that: The temperature of the esterification reaction between isatoic anhydride and methoxypolyethylene glycol is 120°C - 125°C, and the reaction time is 2 - 4h.

3. The high-gloss polypropylene composite material with excellent surface appearance according to claim 1, characterized in that: The catalyst for the esterification reaction is 4-dimethylaminopyridine; the molar ratio of isatoic anhydride to methoxypolyethylene glycol is 1:0.8 - 1.2; the molar ratio of isatoic anhydride to 4-dimethylaminopyridine is 1:0.05 - 0.

2.

4. The high-gloss polypropylene composite material with excellent surface appearance according to claim 1, characterized in that: The temperature of the polymerization reaction between styrene and acrylic acid in the presence of an initiator is 100 - 120°C, and the reaction time is 1 - 3h.

5. The high-gloss polypropylene composite material with excellent surface appearance according to claim 1, characterized in that: The molar ratio of styrene to acrylic acid is 8:1 - 3.

6. The high-gloss polypropylene composite material with excellent surface appearance according to claim 1, characterized in that: The antioxidant is at least one of histamine-based antioxidants, hindered phenol-based antioxidants, and phosphite-based antioxidants.

7. The high-gloss polypropylene composite material with excellent surface appearance according to claim 1, characterized in that: The light stabilizer is a histamine-based light stabilizer.

8. The preparation method of the high-gloss polypropylene composite material with excellent surface appearance according to any one of claims 1 to 7, characterized in that: comprises the following steps: According to the weight ratio, polypropylene, barium sulfate, dressing polymer dispersant, antioxidant, and light stabilizer are added to a high-speed mixer, and dry-mixed at 60°C - 90°C for 5 - 15 minutes, and then the uniform mixed material is added to a twin-screw extruder for melt extrusion and pelletization to obtain the target product.

9. The preparation method of the high-gloss polypropylene composite material with excellent surface appearance according to claim 8, characterized in that: The temperatures of each zone of the twin-screw extruder are as follows: the temperature of the first zone is 170 - 180°C, the temperature of the second zone is 170 - 190°C, the temperature of the third zone is 180 - 200°C, the temperature of the fourth zone is 190 - 210°C, and the temperature of the fifth zone is 190 - 220°C.

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