A high-strength, long-lasting fragrance-retaining polypropylene and preparation method thereof

Abstract

The invention discloses a high-strength, long-lasting, fragrant polypropylene and a preparation method thereof, which are prepared from the following raw materials in parts by mass: 50-95 parts of polypropylene; 0-30 parts of elastomer; 0-40 parts of filler; 0.1-10 parts of POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer; 0.01-10 parts of essence masterbatch; 0.1-3 parts of antioxidant; 0.1-3 parts of lubricant. The modified polypropylene of the present invention has an effective length of fragrance retention of more than 2 years under standard conditions and can also be used at high temperatures. On the other hand, the modified polypropylene prepared by the present invention exhibits excellent mechanical properties. The material can be applied to the fields of home appliances, automobiles, toys, etc., and has broad application prospects and commercial value.

Description

Technical Field

[0001] The invention relates to a polypropylene material, and further to a high-strength, long-lasting, fragrant polypropylene and a preparation method thereof. Background Art

[0002] With the development of the market economy and the improvement of people's living standards, people pay more attention to the quality of life and the safety and comfort of their homes and environments. However, plastic materials used in homes, electronic appliances and cars usually have odors, which reduces consumers' experience and harms people's health. Therefore, plastic products with fragrances are becoming more and more popular. Fragrance plastic products are made by adding flavor enhancers during the product molding process, using the migration of flavor molecules in the material and the volatilization of gases to make the products emit a special fragrance for a long time.

[0003] At present, the key difficulty in the research of scented plastics is how to improve the persistence of scent. The extrusion and injection molding temperature of modified PP is around 200°C. Fragrances are easy to volatilize at high temperatures, making it difficult to ensure a long-lasting fragrance effect. At the same time, modified PP usually requires the addition of a variety of additives, which may affect the diffusion and persistence of the fragrance while improving the performance of the material. In addition, the ingredients of fragrances are generally polar small molecule compounds such as alcohols, esters, aldehydes, and carboxylic acids, while plastic matrices such as polypropylene are non-polar. The two have poor compatibility, and small molecules can easily precipitate onto the plastic surface, making it difficult to control the sustained release of fragrance.

[0004] Research on scented plastics at home and abroad has made certain progress, mainly focusing on four directions. The first is to directly blend and extrude the flavor with the resin, such as the application number 200610157754.3 discloses a scented engineering plastic and its preparation method, and CN201480003989.0 uses aromatic oil as a flavor enhancer and plasticizer, but the compatibility of the flavor with the resin is poor, the flavor volatilizes in large quantities and has poor dispersibility, and the fragrance is not persistent. The second is to composite extrude or injection mold the scented plastic masterbatch with the resin, mainly studying the adsorption performance of different adsorbents and carriers in the scent masterbatch on the fragrance, such as CN200410075857.6 uses kaolin and polyethylene wax, CN201110450573.0 uses calcium carbonate and talcum powder, and CN201710322981.5 uses activated carbon as a fragrance adsorption additive to prepare the scent masterbatch. However, the adsorption performance of these fillers is poor, and there is still the problem of non-persistent volatilization loss of the fragrance. The third is to make flavor microcapsules. Patents CN201010579678.1 and CN201611173289.2 respectively invented a long-lasting sustained-release high-concentration fragrance-containing plastic. The micropores of the microcapsule shell can ensure the slow release of the fragrance, improve its dispersibility in the plastic matrix, and reduce the volatilization loss during high-temperature processing. The fourth is to construct the latent fragrance of the fragrance, that is, to use a certain compound to connect with the fragrance through a covalent bond, and then break the covalent bond under certain conditions to release the fragrance. Patent CN201711133279.0 uses POSS-based 1,2-dihydroxy compounds and fragrance aldehydes and ketones to obtain latent fragrance bodies through condensation reactions to improve the sustained release effect of fragrances on fiber fabrics, but this method has a narrow universality for the types of fragrances, and can only be aldehyde and ketone fragrances. It is not applicable to olefins, carboxylic acids, esters, etc., and only relies on the nanostructure of POSS to enter the fiber cavity to achieve the adsorption and sustained release of fragrance molecules, which has a relatively limited effect. Although a variety of implementation methods have been developed, most of them have the disadvantages that the essence and carrier resin essence are easy to seep out and volatilize, the fragrance is lost quickly, and the fragrance retention effect is poor. At the same time, the preparation process is complicated and the cost is high, which is not conducive to large-scale promotion. Therefore, improving the fragrance retention effect and durability of scented plastics is still a problem that needs to be solved urgently.

[0005] Polyhedral oligomeric silsesquioxane (POSS) is an organic-inorganic intramolecular hybrid material at the molecular level. It is a spatial cage-type nanostructure composed of an inorganic core skeleton alternately connected by Si-O and an organic group connected to the periphery. It combines the toughness, hydrophobicity, and compatibility of organic polymer materials with the stability and heat resistance of inorganic materials. Using POSS as a plasticizer and reinforcing agent to modify polymers can improve the heat resistance, modulus, compressive strength, hardness, and wear resistance of polymer materials. On the one hand, POSS plays a role in chain extension and cross-linking, increasing the viscosity of the resin matrix, thereby increasing the strength of the material. The nano-sized cage structure is conducive to the passage of polymer chains to achieve molecular-level dispersion, while at the same time producing a physical entanglement effect on the polymer chains passing through, increasing the glass transition temperature (T g ) and thermal decomposition temperature (T d On the other hand, the rigid POSS nanoparticles are dispersed in the matrix and can induce silver streaks around them to absorb the impact energy when impacted, thus improving the toughness of the material.

[0006] Adding nucleating agents for modification is a common method to improve the mechanical strength of polypropylene. According to the main components of the nucleating agents, they can be divided into inorganic, organic small molecules, and polymer nucleating agents. The nucleating efficiency of inorganic nucleating agents is low, and they have poor compatibility with the polymer matrix and uneven dispersion. The nucleating efficiency of organic small molecule nucleating agents is high, but there are problems such as high cost, easy agglomeration, difficult dispersion, migration, and toxicity. Based on this, the development of new polymer β nucleating agents has become a research hotspot. Among them, liquid crystal polymers have the advantages of high strength, high modulus, chemical corrosion resistance, and dimensional stability. They can form microfibers in situ with thermoplastics under certain processing conditions, and disperse in the substrate at the molecular level to achieve a reinforcing effect, which has received widespread attention. However, although liquid crystal polymers and PP substrates are both polymers, the two are incompatible systems, and phase separation is prone to occur during the processing process. For example, CN201610941324.4 uses liquid crystal polymer β nucleating agents to improve the impact strength, elongation at break, and heat resistance of PP, but the compatibility problem has not yet been solved. Summary of the invention

[0007] The object of the present invention is to provide a method for preparing high-strength and long-lasting fragrance polypropylene in view of the deficiencies in the prior art, and to improve the dispersibility and compatibility of fragrance in PP substrate by using POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer, slow down the migration rate of fragrance molecules, and effectively prolong the fragrance emission time. At the same time, as a nucleating agent, the mechanical strength of the material is provided, and the compatibility with PP is also improved by modifying the liquid crystal polymer.

[0008] To achieve the above object, the technical solution adopted by the present invention is:

[0009] A modified polypropylene with a long-lasting fragrance is prepared from the following raw materials in parts by weight:

[0010] Polypropylene 50-95 parts;

[0011] Elastomer 0-30 parts, preferably 5-15 parts;

[0012] Filler 0-40 parts, preferably 10-30 parts;

[0013] POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer 0.1-10 parts, preferably 0.5-5 parts;

[0014] 0.01-10 parts of flavor masterbatch, preferably 0.2-2 parts;

[0015] 0.1-3 parts of antioxidant, preferably 0.2-1 parts;

[0016] Lubricant 0.1-3 parts, preferably 0.2-1.5 parts.

[0017] In the present invention, the polypropylene is one or more of homopolymer polypropylene, random copolymer polypropylene and block copolymer polypropylene. Preferably, the melt flow index of the polypropylene is 10-100 g / 10 min at 230° C. and 2.16 kg.

[0018] In the present invention, the elastomer is one or a mixture of two or more of ethylene-butylene copolymer, styrene-ethylene-isobutylene-styrene block copolymer and styrene-isobutylene-styrene block copolymer.

[0019] In the present invention, the filler is one or more of talc, calcium carbonate, diatomaceous earth, kaolin and barium sulfate.

[0020] In the present invention, the structure of the POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer is as shown in the following formula, the number average molecular weight Mn is 5-72 kg / mol, n=9-100, and the R group is one of phenyl, isobutyl, cyclopentyl and the like.

[0021]

[0022] Further, the synthesis method of the POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer is:

[0023] 1) Add 4,4'-biphenyldiphenol to a mixture containing an alkali compound, preferably anhydrous K 2 CO 3 、Na 2 CO 3or NaOH, etc., then add 6-chloro-1-hexanol and KI or CuI, the molar ratio of 4,4'-biphenyldiphenol, 6-chloro-1-hexanol, KI or CuI, and alkaline compounds is (1:3:0.03:9) to (1:5:0.05:12). Heat, condense and reflux for 10 to 24 hours, the reaction temperature is 120-160°C, and filter. Preferably, the filtered product is placed in a beaker, 100 to 200 mL of deionized water is added, stirred evenly, and then the pH is adjusted to 1-3 with concentrated hydrochloric acid, and then the filtered product is repeatedly rinsed with distilled water several times, and finally vacuum dried to obtain a white solid product, biphenyldioxyhexanol.

[0024]

[0025] 2) Dissolve diphenyldioxane in a solvent, preferably DMF, add methacrylic acid and substituted benzoic acid compound A, slowly drop concentrated sulfuric acid, preferably, the molar ratio of the four is (1:2:2:0.1) to (1:4:4:0.4). React at 80-120°C for 10-20h, separate and purify to obtain methacrylate compound B.

[0026]

[0027] 3) Add 3-hydroxypropyl heptaisobutyl POSS to a solvent, preferably DMF, stir for 1 to 2 hours, cool to -20 to 20°C, add triethylamine, slowly dropwise add 2-chloroacetyl chloride under stirring, preferably, the molar ratio of the three is (1:6:5) to (1:12:10), and react at room temperature for 20 to 40 hours. After the reaction is completed, wash the reactant with 0.3 to 0.7 mol / L NaOH solution, 0.3 to 0.7 mol / L hydrochloric acid solution and a large amount of deionized water in sequence, separate and add the lower layer liquid to excess methanol, benzene, acetone or acetonitrile, and vacuum dry the precipitate at 80 to 120°C for 5 to 10 hours to obtain the macromolecular initiator POSS-C1.

[0028] 4) POSS-C1 is dissolved in a solvent, preferably DMF, and then methacrylate compound B is added to stir and dissolve, and ammonia is added. CuC1 and tris(2-dimethylaminoethyl)amine are dissolved in a solvent, preferably DMF, and then added dropwise to a reaction bottle, and reacted at 30-70°C for 1 to 6 hours. Preferably, the molar ratio of POSS-C1, compound B, CuC1, and tris(2-dimethylaminoethyl)amine is (1:50:10:10) to (1:100:20:20). Preferably, after the reaction is completed, separation and purification are performed, and then dialyzed for 1 to 3 days, and the dialyzed aqueous solution is freeze-dried to obtain POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer C.

[0029]

[0030] In the present invention, the fragrance of the flavor masterbatch mainly includes floral fragrance, fruit fragrance and other types, which can withstand high temperatures of 250°C, such as tea fragrance, white chocolate fragrance, violet fragrance, vanilla fragrance, basil fragrance, sandalwood fragrance. Preferably, the carrier of the flavor masterbatch is EVA, which has a linear branched structure, has greater softness and adhesion, a low melting point of about 100°C, and a low processing temperature, which is conducive to the absorption and sustained release of the flavoring agent. The VA content of the EVA is between 5 and 40.

[0031] In the present invention, the antioxidant is a mixture of one or more of a hindered phenol macromolecular antioxidant, a phosphite antioxidant and an alkyl ester antioxidant. Preferably, the phosphite antioxidant is 168, i.e. tris[2.4-di-tert-butylphenyl]phosphite, and the amount added is 0.1-1 part; the hindered phenol antioxidant is 1010, i.e. pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and the amount added is 0.1-1 part.

[0032] In the present invention, the lubricant is a mixture of one or more of polyolefin wax, stearate, stearamide lubricant or polyethylene glycol.

[0033] A method for preparing high-strength long-lasting fragrance polypropylene comprises the following steps:

[0034] (a) preparing POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer;

[0035] (b) weighing each raw material according to the mass percentage;

[0036] (c) polypropylene, elastomer, filler, antioxidant, lubricant, after being uniformly mixed, are put into the main feeding bin of twin-screw extruder, POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer and essence masterbatch are put into the side feeding port, melt-extruded at a temperature of 140° C. to 240° C. and a rotating speed of 400 to 700 r / min, and then granulated and dried to finally obtain high-strength lasting fragrance-retaining polypropylene of the present invention.

[0037] The present invention provides a high-strength, long-lasting fragrance-retaining polypropylene and a preparation method thereof. Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0038] 1. The modified polypropylene of the present invention can effectively release fragrance for a long time, make people feel happy, and meet the needs of consumers. The principle of having a lasting fragrance effect is: 1) The POSS molecule is a cage-like structure of nanometer size. While producing a physical entanglement effect on the polymer chain, it can also efficiently capture the free fragrance small molecule compounds, making the fragrance dispersed more evenly and reducing the speed of migration to the surface of the product. At the same time, POSS, as an organic-inorganic nano hybrid material, can act on non-polar PP resin and polar EVA fragrance carrier at the same time, improving the compatibility of fragrance masterbatch with matrix resin. And grafting POSS to liquid crystal polymer can increase its molecular weight and reduce the risk of precipitation. 2) The POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer in the present invention contains phenyl and ester bonds in the side chain, and the fragrance molecules are mainly organic small molecules such as alcohols, esters, aldehydes, etc. containing aromatic groups, and have similar miscible properties. The side chain benzene rings of the liquid crystal polymer are stacked in an orderly manner, which has a large steric hindrance and can increase the spacing between the molecular chains, further adsorbing the fragrance in the gaps between the polymer chains, achieving a slow-release effect. Under standard conditions, the effective length of aroma retention can reach more than 2 years, and it can also be used at high temperatures.

[0039] 2. The modified polypropylene of the present invention shows excellent mechanical strength and can be applied to the fields of household appliances, automobiles, toys, etc., and is promoted and applied in a wider market environment. On the one hand, the POSS skeleton is dispersed in the matrix, and when impacted, it can cause silver streaks to absorb impact energy and improve the toughness of the material. On the other hand, the side chain benzene rings of the liquid crystal polymer are stacked in parallel in an orderly manner to form a strong π-π interaction, which acts as a crystal nucleus to induce polypropylene to form β crystals and improve the rigidity of the material. The terminal olefin structure on the side chain can improve the compatibility of the POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer with polypropylene. DETAILED DESCRIPTION

[0040] The following will further introduce and demonstrate specific embodiments within the scope of the present invention through specific examples. These examples are merely illustrative, rather than limiting the scope of the present invention, because many changes may be made to the present invention without departing from its essence and scope.

[0041] Unless otherwise specified, all formulations and tests herein took place at 25°C.

[0042] As used herein, "includes," "comprising," "including," "containing," "having," or other variations are intended to encompass non-exclusive inclusions, and no distinction is made between these terms. The term "comprising" means that other steps and ingredients that do not affect the end result may be added. The term "comprising" also includes the terms "consisting of" and "consisting essentially of." The compositions and methods / processes of the present invention may comprise, consist of, and consist essentially of the essential elements and limitations described herein, as well as any additional or optional ingredients, components, steps, or limitations described herein.

[0043] Unless otherwise specified, all raw materials and reagents involved in the experiments were purchased from commercial sources.

[0044] Table 1 Related raw material information

[0045]

[0046]

[0047] The test methods used or possibly used in the embodiments and comparative examples are described below.

[0048] Table 2 Related test methods

[0049]

[0050] Example 1

[0051] (a) Preparation of heptaisobutyl POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer. 4,4'-biphenyl diphenol was added to anhydrous K 2 CO 3 6-chloro-1-hexanol and KI were added to a DMF solution (4,4'-biphenol to solution molar ratio 1:50), 4,4'-biphenol, 6-chloro-1-hexanol, KI, K 2 CO 3The molar ratio is 1:3:0.03:9. Heat, condense and reflux for 20h, the reaction temperature is 140℃, and filter. Place the filtered product in a beaker, add 200mL of deionized water, stir evenly, adjust the pH to 2 with concentrated hydrochloric acid, filter the product, rinse it repeatedly with distilled water 3 times, and finally vacuum dry it to obtain a white solid product, diphenyldioxanol. Dissolve diphenyldioxanol in solvent DMF (molar ratio 1:40), add methacrylic acid and substituted benzoic acid compounds, and slowly drop concentrated sulfuric acid. The molar ratio of the four is 1:3:3:0.2. React at 100℃ for 20h, separate and purify to obtain methacrylate compounds. Add 3-hydroxypropyl heptaisobutyl POSS to DMF (molar ratio 1:20), stir for 1h, cool to 0℃, add triethylamine, and slowly drop 2-chloroacetyl chloride under stirring. The molar ratio of the three is 1:9:8, and react at room temperature for 24h. After the reaction, the reactants were washed with 0.5 mol / L NaOH solution, 0.5 mol / L hydrochloric acid solution and a large amount of deionized water in turn. After separation, the lower layer was added to excess methanol, and the precipitate was vacuum dried at 100°C for 8 hours to obtain the macroinitiator heptaisobutyl POSS-C1. Heptaisobutyl POSS-C1 was dissolved in DMF (molar ratio 1:30), and then methacrylate compounds were added and stirred to dissolve, and ammonia was filled. After CuC1 and tris(2-dimethylaminoethyl)amine were dissolved in DMF (molar ratio 1:20), they were added dropwise to the reaction bottle and reacted at 50°C for 5 hours. The molar ratio of POSS-C1, methacrylate compounds, CuC1, and tris(2-dimethylaminoethyl)amine was 1:50:10:10. After the reaction, column chromatography was used for separation and purification, and then dialyzed for 2 days. The dialyzed aqueous solution was freeze-dried at -20°C for 24 hours to obtain a heptaisobutyl POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer with a number average molecular weight of Mn = 51.8 kg / mol and n = 71. The chemical structure of the product was analyzed by infrared spectrometer at 3030 cm -1 The stretching vibration peaks of olefin =CH appear at 2930 and 2838 cm -1 -CH appears 2 - stretching vibration peak, 1730cm -1 The stretching vibration peaks of the ester group C=O appear at 1459 and 1377 cm -1 Saturated -CH 3 The deformation vibration peak, 1173cm -1 The stretching vibration peak of Si-O-Si appears at 1501cm -1 The stretching vibration peak of the benzene ring C=C appears at 823cm -1 The stretching vibration peak of benzene ring -CH appears at

[0052] (b) weighing each raw material according to the mass parts;

[0053] (c) copolymerized polypropylene, elastomer, talcum powder, antioxidant and lubricant are mixed and dropped into the main feeding bin of twin screw extruder, 3 parts of POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer and 0.5 part of tea flavor masterbatch are dropped into side feeding port, and the screw temperature is set to 140 ℃, 180 ℃, 210 ℃, 210 ℃, 210 ℃, 210 ℃, 210 ℃, 210 ℃, 200 ℃, 200 ℃ from feed port to die head segmentation, screw speed 600r / min, granulation and drying after melt-extrusion, finally obtain high strength lasting and fragrant polypropylene of the present invention.

[0054] Example 2

[0055] (a) Preparation of heptacyclopentyl POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer. 4,4'-biphenyl diphenol was added to anhydrous Na 2 CO 3 6-chloro-1-hexanol and KI, 4,4'-biphenol, 6-chloro-1-hexanol, KI, Na 2 CO 3The molar ratio is 1:3:0.05:10. Heat, condense and reflux for 20h, the reaction temperature is 140℃, and filter. Place the filtered product in a beaker, add 200mL of deionized water, stir evenly, adjust the pH to 2 with concentrated hydrochloric acid, filter the product and rinse it repeatedly with distilled water 3 times, and finally vacuum dry to obtain a white solid product, diphenyldioxanol. Dissolve diphenyldioxanol in solvent DMF (molar ratio 1:40), add methacrylic acid and substituted benzoic acid compounds, and slowly drop concentrated sulfuric acid. The molar ratio of the four is 1:3:2:0.2. React at 100℃ for 20h, separate and purify to obtain methacrylate compounds. Add 3-hydroxypropyl heptacyclopentyl POSS to DMF (molar ratio 1:20), stir for 1h, cool to 0℃, add triethylamine, and slowly drop 2-chloroacetyl chloride under stirring. The molar ratio of the three is 1:12:10, and react at room temperature for 24h. After the reaction, the reactants were washed with 0.5 mol / L NaOH solution, 0.5 mol / L hydrochloric acid solution and a large amount of deionized water in turn. After separation, the lower layer was added to excess methanol, and the precipitate was vacuum dried at 100°C for 8 hours to obtain the macroinitiator heptacyclopentyl POSS-C1. Heptacyclopentyl POSS-C1 was dissolved in DMF (molar ratio 1:30), and then methacrylate compounds were added and stirred to dissolve, and ammonia was charged. After CuC1 and tris(2-dimethylaminoethyl)amine were dissolved in DMF (molar ratio 1:20), they were added dropwise to the reaction bottle and reacted at 50°C for 6 hours. The molar ratio of POSS-C1, methacrylate compounds, CuC1, and tris(2-dimethylaminoethyl)amine was 1:70:15:15. After the reaction, column chromatography was used for separation and purification, and then dialyzed for 2 days. The dialyzed aqueous solution was freeze-dried at -20°C for 24 hours to obtain a seven-cyclopentyl POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer with a number average molecular weight of Mn = 67.2 kg / mol and n = 92. The chemical structure of the product was analyzed by infrared spectrometer at 3032 cm -1 The stretching vibration peaks of olefin =CH appear at 2921 and 2837 cm -1 -CH appears 2 - stretching vibration peak, 1721cm -1 The stretching vibration peaks of the ester group C=O appear at 1460 and 1377 cm -1 Saturated -CH 3 The deformation vibration peak, 1167cm -1 The stretching vibration peak of Si-O-Si appears at 1549 cm -1 The stretching vibration peak of benzene ring C=C appears at 822cm -1 The stretching vibration peak of benzene ring -CH appears at 720cm -1 Appears at (CH 2 )n stretching vibration peak;

[0056] (b) weighing each raw material according to the weight percentage;

[0057] (c) copolymerized polypropylene, elastomer, talcum powder, antioxidant, lubricant are mixed and dropped into the main feeding bin of twin screw extruder, 0.5 part of POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer and 2 parts of violet essence masterbatch are dropped into side feeding port, screw temperature is set to 140 ℃, 180 ℃, 210 ℃, 210 ℃, 210 ℃, 210 ℃, 210 ℃, 210 ℃, 200 ℃, 200 ℃ from feed opening to die head segmentation, screw speed 600r / min, granulation and drying after melt-extruding, finally obtain high strength lasting fragrance polypropylene of the present invention.

[0058] Example 3

[0059] (a) Preparation of heptaphenyl POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer. 4,4'-biphenyl diphenol was added to anhydrous K 2 CO 3 6-chloro-1-hexanol and CuI, 4,4'-biphenol, 6-chloro-1-hexanol, KI, K 2 CO 3The molar ratio is 1:4:0.04:12. Heat, condense and reflux for 15h, the reaction temperature is 140℃, and filter. Place the filtered product in a beaker, add 200mL of deionized water, stir evenly, adjust the pH to 2 with concentrated hydrochloric acid, filter the product and rinse it repeatedly with distilled water 3 times, and finally vacuum dry to obtain a white solid product, diphenyldioxanol. Dissolve diphenyldioxanol in solvent DMF (molar ratio 1:40), add methacrylic acid and substituted benzoic acid compounds, and slowly drop concentrated sulfuric acid. The molar ratio of the four is 1:4:4:0.4. React at 100℃ for 20h, separate and purify to obtain methacrylate compounds. Add 3-hydroxypropyl heptaphenyl POSS to DMF (molar ratio 1:20), stir for 2h, cool to -10℃, add triethylamine, and slowly drop 2-chloroacetyl chloride under stirring. The molar ratio of the three is 1:6:6, and react at room temperature for 30h. After the reaction, the reactants were washed with 0.5 mol / L NaOH solution, 0.5 mol / L hydrochloric acid solution and a large amount of deionized water in turn. After separation, the lower layer was added to excess methanol, and the precipitate was vacuum dried at 100°C for 10 hours to obtain the macroinitiator heptaphenyl POSS-C1. Heptaphenyl POSS-C1 was dissolved in DMF (molar ratio 1:30), and then methacrylate compounds were added and stirred to dissolve, and ammonia was filled. After CuC1 and tris(2-dimethylaminoethyl)amine were dissolved in DMF (molar ratio 1:20), they were added dropwise to the reaction bottle, and reacted at 50°C for 5 hours. The molar ratio of POSS-C1, methacrylate compounds, CuC1, and tris(2-dimethylaminoethyl)amine was 1:100:20:20. After the reaction, column chromatography was used for separation and purification, and then dialyzed for 2 days. The dialyzed aqueous solution was freeze-dried at -20°C for 24 hours to obtain a heptaphenyl POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer with a number average molecular weight of Mn = 26.9 kg / mol and n = 36. The chemical structure of the product was analyzed by infrared spectrometer at 3025 cm -1 The stretching vibration peaks of olefin =CH appear at 2923 and 2837 cm -1 -CH appears 2 - stretching vibration peak, 1715cm -1 The stretching vibration peaks of the ester group C=O appear at 1459 and 1377 cm -1 Saturated -CH 3 The deformation vibration peak, 1162cm -1 The stretching vibration peak of Si-O-Si appears at 1504 cm -1 The stretching vibration peak of the benzene ring C=C appears at 820cm -1 The stretching vibration peak of benzene ring -CH appears at

[0060] (b) weighing each raw material according to the weight percentage;

[0061] (c) copolymerized polypropylene, elastomer, calcium carbonate, antioxidant and lubricant are mixed and dropped into the main feeding bin of twin-screw extruder, 5 parts of POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer and 1 part of tea flavor masterbatch are dropped into the side feeding port, and the screw temperature is set to 140°C, 180°C, 210°C, 210°C, 210°C, 210°C, 210°C, 210°C, 200°C, 200°C from the feed port to the head, and the screw speed is 600r / min. Granulation and drying after melt-extrusion finally obtain high-strength lasting and fragrant polypropylene of the present invention.

[0062] Comparative Example 1

[0063] Commercially available liquid crystal polymer E6008 was used as a raw material to replace the prepared POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer, and modified polypropylene was prepared according to the method in Example 1.

[0064] Comparative Example 2

[0065] Commercially available 3-hydroxypropyl heptaisobutyl POSS was used as a raw material to replace the prepared POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer, and polypropylene was prepared according to the method in Example 1.

[0066] Comparative Example 3

[0067] Polypropylene was prepared according to the method in Example 1, except that no POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer was added.

[0068] Table 3 Material ratios of the embodiments and comparative examples

[0069]

[0070] Modified polypropylene pellets were prepared according to the above preparation method, and then injection molded into specimens for performance testing. The results are shown in Table 4.

[0071] Table 4 Performance test results of the products obtained from Examples 1 to 3 and Comparative Examples 1 to 3

[0072]

[0073] Note: Use gel permeation chromatography to test the molecular weight of the material. Since the filler will affect the molecular weight test, xylene is selected as the solvent after removing the filler.

[0074] Persistence evaluation of fragrance: The samples of the above-mentioned examples and comparative examples were placed at 110°C for 200 hours, 600 hours and at room temperature for 8 months, and then the fragrance was evaluated and scored. Five testers were asked to evaluate the odor according to the PV3900 standard. The score of each item was the average of the scores of the five testers, and the total score was 6. The results are shown in Table 5.

[0075] Table 5 Odor evaluation of the products obtained from Examples 1 to 3 and Comparative Examples 1 to 3

[0076]

[0077]

[0078] As can be seen from Table 4, in Examples 1 to 3, after adding POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer, the tensile, bending and impact properties of the material are significantly improved, and the heat deformation temperature is increased from 99° C. to 116° C. This shows that the POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer in the present invention plays a reinforcing and toughening role in the material. When the POSS end is impacted, silver streaks are induced to absorb impact energy, which plays a toughening role, and the polyacrylic acid side chain benzene ring liquid crystal polymer end acts as a nucleating agent, which plays a reinforcing role and has good compatibility with the PP matrix.

[0079] As can be seen from Table 5, compared with the comparative example, the fragrance of Examples 1 to 3 can be maintained for a longer time. After being placed at room temperature for 1 year and at a high temperature of 110°C for 600 hours, the fragrance can be maintained, while the fragrance of the comparative example is basically dissipated cleanly, indicating that the POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer in the present invention has excellent compatibility and adsorption effect on the fragrance molecules, thereby achieving better sustained release and long-lasting fragrance effects.

[0080] The invention is applicable to various fragrance types and material systems, can significantly slow down the seepage and volatilization of fragrance in the matrix resin, reduce the loss rate, make the fragrance more lasting, and has excellent mechanical properties and high promotion value.

[0081] The above is a detailed introduction to a high-strength, long-lasting fragrance-retaining polypropylene and a preparation method thereof provided by the present invention, and the principle and implementation method of the present invention are explained by using specific examples. Finally, it should be noted that the above is only a preferred implementation method of the present invention, and its description is relatively specific and detailed, and it does not limit the present invention in any other form. For ordinary technicians in this technical field, without departing from the method of the present invention, several improvements, supplements and modifications can be made, and these improvements, supplements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A high-strength, long-lasting fragrance-retaining polypropylene. Features: It is prepared from the following raw materials in parts by weight: Polypropylene 50-95 parts; Elastomer 0-30 parts; Filler 0-40 parts; POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer 0.1-10 parts; Fragrance masterbatch 0.01-10 parts; Antioxidant 0.1-3 parts; Lubricant 0.1-3 parts; The structure of the POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer is shown in the following formula, the number average molecular weight Mn is 5 to 72 kg / mol, n=9 to 100, and the R group is one of phenyl, isobutyl, and cyclopentyl.

2. The polypropylene according to claim 1, It is characterized in that It is prepared from the following raw materials in parts by weight: Polypropylene 50-95 parts; Elastomer 5-15 parts; 10-30 parts of filler; 0.5-5 parts of POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer; Fragrance masterbatch 0.2-2 parts; Antioxidant 0.2-2 parts; Lubricant 0.2-1.5 parts.

3. The polypropylene according to claim 1, Features: The polypropylene is one or more of homopolymer polypropylene, random copolymer polypropylene and block copolymer polypropylene, wherein the melt flow index is 10 to 100 g / 10 min at 230° C. and 2.16 kg.

4. The polypropylene according to claim 1, It is characterized in that The elastomer is one or more of ethylene-butylene copolymer, styrene-ethylene-isobutylene-styrene block copolymer and styrene-isobutylene-styrene block copolymer; and / or the filler is one or more of talc, calcium carbonate, diatomaceous earth, kaolin and barium sulfate.

5. The polypropylene according to claim 1, It is characterized in that The preparation of the POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer comprises the following steps: 1) Add 4,4'-biphenyldiphenol to a DMF solution containing an alkali compound, then add 6-chloro-1-hexanol and KI or CuI, heat and condense under reflux for 10 to 24 hours, and the reaction temperature is 120-160°C to obtain biphenyldioxyhexanol; 2) dissolving biphenyldioxane in a solvent, adding methacrylic acid, substituted benzoic acid compound A, and concentrated sulfuric acid; reacting at 80-120° C. for 10-20 hours, and separating and purifying to obtain methacrylate compound B; 3) Add 3-hydroxypropyl heptaisobutyl POSS to DMF, add triethylamine, add 2-chloroacetyl chloride under stirring, and react at room temperature for 20 to 40 hours to obtain macroinitiator POSS-C1; 4) POSS-C1 is dissolved in a solvent and added to the reaction, and then methacrylate compound B is added and stirred to dissolve, and ammonia is added. CuC1 and tris(2-dimethylaminoethyl)amine are dissolved in a solvent, and then added to the reaction bottle, and reacted at 30-70°C for 1-6h to obtain POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer C.

6. The polypropylene according to claim 5, It is characterized in that In step 1), the base compound is anhydrous K 2 CO 3 、Na 2 CO 3 or NaOH.

7. The polypropylene according to claim 5, It is characterized in that In step 1), the molar ratio of 4,4'-biphenol, 6-chloro-1-hexanol, KI or CuI, and the alkaline compound is (1:3:0.03:9) to (1:5:0.05:12).

8. The polypropylene according to claim 5, It is characterized in that In steps 2) and 4), the solvent is DMF.

9. The polypropylene according to claim 5, It is characterized in that In step 2), the molar ratio of diphenyldioxane, methacrylic acid, substituted benzoic acid compound A, and concentrated sulfuric acid is (1:2:2:0.1) to (1:4:4:0.4).

10. The polypropylene according to claim 5, It is characterized in that In step 3), 3-hydroxypropyl heptaisobutyl POSS is added to DMF, stirred for 1 to 2 hours, cooled to -20 to 20°C, and triethylamine is added.

11. The polypropylene according to claim 5, It is characterized in that In step 3), the molar ratio of 3-hydroxypropyl heptaisobutyl POSS, triethylamine and 2-chloroacetyl chloride is (1:6:5) to (1:12:10).

12. The polypropylene according to claim 5, It is characterized in that In step 4), the molar ratio of POSS-C1, methacrylate compound B, CuC1, and tris(2-dimethylaminoethyl)amine is (1:50:10:10) to (1:100:20:20).

13. The polypropylene according to claim 1 or 2, It is characterized in that The flavor masterbatch is one or more of tea flavor, white chocolate flavor, violet flavor, vanilla flavor, basil flavor, and sandalwood flavor.

14. The polypropylene according to claim 13, It is characterized in that The carrier of the flavor masterbatch is EVA.

15. The polypropylene according to claim 1 or 2, It is characterized in that The antioxidant is a mixture of one or more of a hindered phenol macromolecular antioxidant, a phosphite antioxidant and an alkyl ester antioxidant.

16. The polypropylene according to claim 15, It is characterized in that The phosphorous acid antioxidant is 168, and the added amount is 0.1-1 part. The hindered phenol macromolecular antioxidant is 1010, and the added amount is 0.1-1 part.

17. The polypropylene according to claim 1 or 2, It is characterized in that The lubricant is a mixture of one or more of polyolefin wax, stearate, stearamide lubricant or polyethylene glycol.

18. A method for preparing the polypropylene according to any one of claims 1 to 17, The following steps are involved: Polypropylene, elastomer, filler, antioxidant and lubricant are mixed evenly and then fed into the main feeding bin of the twin-screw extruder. POSS-based polyacrylic acid side chain benzene ring liquid crystal polymer and flavor masterbatch are fed into the side feeding port. The mixture is melt-extruded at a temperature of 140°C to 240°C and a rotation speed of 400 to 700 r / min, and then granulated and dried.

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