Preparation method and application of polypropylene with high melt strength

Abstract

The invention discloses a preparation method and application of high-melt-strength polypropylene, and relates to the technical field of high polymer materials. The invention aims to solve the problem of low melt strength of polypropylene prepared by the traditional process. The method comprises the following steps: S1, adding polypropylene, a difurfuryl sulfide monomer, an interface agent, a co-monomer, a main antioxidant, an auxiliary antioxidant, an initiator and deionized water into a reaction kettle, carrying out a full swelling reaction, heating to 80-95 DEG C, and carrying out a grafting reaction at 80-95 DEG C for 0.5-8 h; and S2, firstly soaking the grafted product by using a solvent, then extracting by using an organic solvent, and finally drying to obtain the high-melt-strength polypropylene. The invention can obtain the preparation method and the application of the high-melt-strength polypropylene.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to a method for preparing high melt strength polypropylene, and in particular to a method for preparing high melt strength polypropylene by using diffuryl sulfide as a monomer to modify long-chain branched polypropylene. Background Art

[0002] Polypropylene (PP) is one of the most widely used and fastest growing resins in the world. Compared with the other three general thermoplastic resins (polyethylene, polyvinyl chloride and polystyrene), it has the advantages of low density, high melting point, wide source, low price and easy recycling, tasteless and odorless, excellent mechanical properties and good chemical stability. In recent years, polypropylene has become one of the indispensable basic raw materials in packaging, light industry, construction, electronics, electrical appliances and automobile industries.

[0003] However, due to the linear structure of polypropylene itself, the softening point of the polymer is very close to the melting point, and the melting range is relatively short. During the thermoforming process, when the temperature is higher than the melting point, the melt viscosity drops sharply and strain hardening cannot occur when stretched in the molten state, which leads to poor anti-sag of the polymer, uneven wall thickness of thermoformed products, edge curling and shrinkage during extrusion coating and calendering, and cell collapse during extrusion foaming. This shortcoming greatly limits the application of polypropylene in thermoforming, foaming, extrusion coating and blow molding. At the same time, the global overproduction of PP will gradually emerge in recent years. The fierce market competition has caused the world's PP manufacturers to gradually increase their investment in the diversification and functionalization of PP varieties, and the development of high melt strength polypropylene has received increasing attention.

[0004] High melt strength polypropylene (HMSPP) is a new type of polypropylene material developed to address the problem of low melt strength of polypropylene. At present, high melt strength polypropylene (HMSPP) is usually produced by melt grafting, solution grafting, solid phase grafting, suspension grafting and radiation grafting. However, the polypropylene produced by the above traditional processes usually has the problem of low melt strength. Based on this, designing an innovative preparation process for high melt strength polypropylene (HMSPP) has become a common problem that needs to be solved in the industry. Summary of the invention

[0005] The purpose of the present invention is to solve the problem of low melt strength of polypropylene prepared by traditional process and to provide a preparation method and application of high melt strength polypropylene.

[0006] A method for preparing high melt strength polypropylene is carried out according to the following steps:

[0007] Step S1: adding polypropylene, difurfuryl sulfide monomer, interface agent, comonomer, primary antioxidant, secondary antioxidant, initiator and deionized water into a reactor, heating to 80-95° C. after sufficient swelling reaction, and grafting reaction at 80-95° C. for 0.5-8h; the mass ratio of polypropylene to difurfuryl sulfide monomer is 10:(0.25-8);

[0008] Step S2: soaking the grafted product in step S1 with a solvent, then extracting it with an organic solvent, and finally drying it.

[0009] The invention discloses an application of high melt strength polypropylene, wherein the high melt strength polypropylene is applied in the fields of packaging, light industry, construction, electronics, electrical appliances and automobiles.

[0010] Beneficial effects of the present invention:

[0011] The invention discloses a method for preparing high melt strength polypropylene. The preparation process is adjusted to adjust the grafting effect of the high melt strength polypropylene, so as to enhance the melt strength of the polypropylene and further improve the application performance.

[0012] The invention can obtain a preparation method and application of high melt strength polypropylene. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 FT-IR image of the original polypropylene in the comparative example is shown;

[0014] Figure 2 represents the XRD pattern of the original polypropylene in the comparative example;

[0015] Figure 3 DMA image showing the original polypropylene in the comparative example;

[0016] Figure 4 FT-IR image showing the high melt strength polypropylene in Example 1;

[0017] Figure 5 represents the XRD pattern of the high melt strength polypropylene in Example 1;

[0018] Figure 6 DMA image showing the high melt strength polypropylene in Example 1;

[0019] Figure 7 FT-IR image showing the high melt strength polypropylene in Example 2;

[0020] Figure 8 represents the XRD pattern of the high melt strength polypropylene in Example 2;

[0021] Fig. 9DMA image showing the high melt strength polypropylene in Example 2;

[0022] Fig.10 FT-IR image showing the high melt strength polypropylene in Example 3;

[0023] Fig.11 represents the XRD pattern of the high melt strength polypropylene in Example 3;

[0024] Fig.12 DMA image showing the high melt strength polypropylene in Example 3;

[0025] Fig.13 FT-IR image showing the high melt strength polypropylene in Example 4;

[0026] Fig.14 represents the XRD pattern of the high melt strength polypropylene in Example 4;

[0027] Fig.15 DMA image showing the high melt strength polypropylene of Example 4. DETAILED DESCRIPTION

[0028] Specific implementation method 1: This implementation method is a method for preparing high melt strength polypropylene, which is carried out according to the following steps:

[0029] Step S1: adding polypropylene, difurfuryl sulfide monomer, interface agent, comonomer, primary antioxidant, secondary antioxidant, initiator and deionized water into a reactor, heating to 80-95° C. after sufficient swelling reaction, and grafting reaction at 80-95° C. for 0.5-8h; the mass ratio of polypropylene to difurfuryl sulfide monomer is 10:(0.25-8);

[0030] Step S2: soaking the grafted product in step S1 with a solvent, then extracting it with an organic solvent, and finally drying it.

[0031] Specific embodiment 2: The difference between this embodiment and specific embodiment 1 is that the mass ratio of the interfacial agent, co-monomer, primary antioxidant, auxiliary antioxidant, initiator, deionized water and polypropylene is (0.5-8): (1-4): (0.01-0.08): (0.01-0.06): (0.01-0.08): (10-80): 10.

[0032] The other steps are the same as those in the first specific implementation.

[0033] Specific embodiment three: The difference between this embodiment and specific embodiment one or two is that the initiator is one or more of diisopropylbenzene peroxide (DCP), dibenzoyl peroxide (BPO), azobisisobutyronitrile (AIBN), tert-butyl perbenzoate (TPB), bis(2-phenylethoxy) peroxydicarbonate (BPPD), dicyclopentadiene (DCPD) and ammonium persulfate (APS).

[0034] The other steps are the same as those in the first or second embodiment.

[0035] Specific implementation method 4: This implementation method is different from specific implementation methods 1 to 3 in that: the interface agent is one or more of benzene, toluene, xylene and cyclohexane; the comonomer is styrene and / or acrylic acid.

[0036] The other steps are the same as those in Specific Embodiments 1 to 3.

[0037] Specific embodiment 5: The difference between this embodiment and specific embodiments 1 to 4 is that the main antioxidant is tetrakis[B-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester (antioxidant 1010), B-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl alcohol ester (antioxidant 1076), 2,2'-methylenebis(4-methyl-6-tert-butylphenol) (antioxidant 2246), 1.1.3-tris(2-methyl-4- The invention relates to one or more of hydroxy-5-tert-butylphenyl) butane (antioxidant CA) and bis(2,4-di-tert-butylphenol) pentaerythritol diphosphite (antioxidant 626); the auxiliary antioxidant is one or more of tris(2,4-di-tert-butylphenyl phosphite) (antioxidant 168), triphenyl phosphite (TPP), trinonylphenyl phosphite (TNP), dilauryl thiodipropionate (antioxidant DLTP) and octadecyl thiodipropionate (antioxidant DSTP).

[0038] The other steps are the same as those in Specific Embodiments 1 to 4.

[0039] Specific embodiment 6: The difference between this embodiment and specific embodiments 1 to 5 is that the swelling temperature is 40 to 80° C. and the swelling time is 20 min to 5 h.

[0040] The other steps are the same as those in Specific Embodiments 1 to 5.

[0041] Specific implementation method 7: The difference between this implementation method and specific implementation methods 1 to 6 is that the solvent used for immersion is one or both of anhydrous ethanol and deionized water, and the immersion time is 1 to 12 hours.

[0042] The other steps are the same as those in Specific Embodiments 1 to 6.

[0043] Specific embodiment eight: This embodiment differs from specific embodiments one to seven in that the organic solvent used for extraction is acetone, and the extraction time is 2 to 36 hours.

[0044] The other steps are the same as those in Specific Embodiments 1 to 7.

[0045] Specific embodiment 9: The difference between this embodiment and specific embodiments 1 to 8 is that the drying temperature is 35-70°C.

[0046] The other steps are the same as those in Specific Embodiments 1 to 8.

[0047] Specific implementation method ten: This implementation method is an application of high melt strength polypropylene, and the high melt strength polypropylene is used in the fields of packaging, light industry, construction, electronics, electrical appliances and automobiles.

[0048] The following examples are used to verify the beneficial effects of the present invention:

[0049] Example 1: A method for preparing high melt strength polypropylene is carried out according to the following steps:

[0050] Step S1: 10 g of polypropylene, 0.25 g of difurfuryl sulfide monomer, 2 g of xylene interfacial agent, 4 g of styrene comonomer, 0.02 g of tetrakis[B-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] pentaerythritol ester primary antioxidant, 0.01 g of tris(2,4-di-tert-butylphenyl) phosphite secondary antioxidant, 0.04 g of diisopropylbenzene peroxide initiator and 25 g of deionized water were added into a beaker, and the mixture was swollen for 1 h at 60° C.;

[0051] Step S2: After sufficient swelling reaction, the temperature is raised to 90° C., and grafting reaction is carried out at 90° C. for 4 hours;

[0052] Step S3: Purify the grafted product by first soaking it in deionized water and anhydrous ethanol for 6 hours respectively to remove impurities; then extract it with acetone for 12 hours, and finally dry it at 45°C.

[0053] Example 2: A method for preparing high melt strength polypropylene is carried out according to the following steps:

[0054] Step S1: 10 g of polypropylene, 0.5 g of difurfuryl sulfide monomer, 2 g of toluene interfacial agent, 4 g of acrylic acid comonomer, 0.02 g of B-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate n-octadecyl alcohol primary antioxidant, 0.04 g of dibenzoyl peroxide initiator and 25 g of deionized water were added into a beaker, and the mixture was swollen for 1 h at 70° C.;

[0055] Step S2: After sufficient swelling reaction, the temperature is raised to 95° C., and grafting reaction is carried out at 95° C. for 4 hours;

[0056] Step S3: purifying the grafted product by first soaking it in deionized water and anhydrous ethanol for 8 hours respectively to remove impurities; then extracting it with acetone for 6 hours, and finally drying it at a temperature of 60°C.

[0057] Example 3: A method for preparing high melt strength polypropylene is carried out according to the following steps:

[0058] Step S1: 10 g of polypropylene, 0.75 g of difurfuryl sulfide monomer, 2 g of xylene interfacial agent, 4 g of styrene comonomer, 0.02 g of B-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate n-octadecyl alcohol primary antioxidant, 0.04 g of diisopropyl peroxide initiator and 20 g of deionized water were added into a beaker, and the mixture was swelled for 2 h at 70° C.;

[0059] Step S2: After sufficient swelling reaction, the temperature is raised to 90° C., and grafting reaction is carried out at 90° C. for 6 hours;

[0060] Step S3: Purify the grafted product by first soaking it in deionized water and anhydrous ethanol for 12 hours respectively to remove impurities; then extract it with acetone for 8 hours, and finally dry it at 70°C.

[0061] Example 4: A method for preparing high melt strength polypropylene is carried out according to the following steps:

[0062] Step S1: 10 g of polypropylene, 1 g of difurfuryl sulfide monomer, 2 g of xylene interfacial agent, 4 g of acrylic acid comonomer, 0.04 g of tetrakis[B-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol primary antioxidant, 0.01 g of tris(2,4-di-tert-butylphenyl)phosphite secondary antioxidant, 0.08 g of diisopropylbenzene peroxide initiator and 40 g of deionized water were added into a beaker, and the mixture was swollen for 2 h at 60° C.;

[0063] Step S2: After sufficient swelling reaction, the temperature is raised to 90° C., and grafting reaction is carried out at 90° C. for 3 h;

[0064] Step S3: Purify the grafted product by first soaking it in deionized water and anhydrous ethanol for 6 hours respectively to remove impurities; then extract it with acetone for 12 hours, and finally dry it at 45°C.

[0065] Figure 1-3 They respectively represent the FT-IR image, XRD image and DMA image of the original polypropylene in the comparative example, Figure 4-6FT-IR image, XRD image and DMA image of high melt strength polypropylene in Example 1 are shown respectively, Figure 7-9 FT-IR image, XRD image and DMA image of high melt strength polypropylene in Example 2 are shown respectively. Figure 10-12 FT-IR image, XRD image and DMA image of high melt strength polypropylene in Example 3 are shown respectively. Figure 13-15 The FT-IR image, XRD image and DMA image of the high melt strength polypropylene in Example 4 are respectively shown.

[0066] Figure 4 , Figure 7 , Fig.10 and Fig.13 This is the FT-IR image of long-chain branched modified polypropylene using diffuryl sulfide as a monomer. The image shows that different processes successfully grafted different contents of diffuryl sulfide onto the polypropylene molecular chain, and different characteristic peak sizes represent different grafting rates of different diffuryl sulfides.

[0067] Figure 5 , Figure 8 , Fig.11 and Fig.14 This is the XRD image of long-chain branched modified polypropylene using diffuryl sulfide as a monomer. The image shows that the crystallization of long-chain branched modified polypropylene with diffuryl sulfide at different grafting rates is ideal.

[0068] Figure 6 , Fig. 9 , Fig.12 and Fig.15 The DMA image of long-chain branched polypropylene modified by using difurfuryl sulfide as a monomer shows that the mechanical properties of long-chain branched polypropylene modified by using difurfuryl sulfide as a monomer under different processes at 30-150°C are greatly improved, and high melt strength polypropylene with ideal performance is prepared. Compared with the original polypropylene, the high melt strength polypropylene prepared by the present invention has an increase of 10-30% in storage modulus and 10-45% in loss modulus at 25°C; an increase of 5-25% in storage modulus and 5-30% in loss modulus at 140°C; it fully proves that the mechanical properties of the polypropylene modified by long-chain branching in the present invention are significantly improved, and high melt strength polypropylene with ideal performance is prepared.

Claims

1. A method for preparing high melt strength polypropylene, characterized in that: The preparation method is carried out according to the following steps: Step S1: adding polypropylene, difurfuryl sulfide monomer, interface agent, comonomer, primary antioxidant, secondary antioxidant, initiator and deionized water into a reactor, heating to 80-95° C. after sufficient swelling reaction, and grafting reaction at 80-95° C. for 0.5-8h; the mass ratio of polypropylene to difurfuryl sulfide monomer is 10:(0.25-8); Step S2: soaking the grafted product in step S1 with a solvent, then extracting it with an organic solvent, and finally drying it.

2. The method for preparing a high melt strength polypropylene according to claim 1, characterized in that: The mass ratio of the interface agent, comonomer, primary antioxidant, auxiliary antioxidant, initiator, deionized water and polypropylene is (0.5-8): (1-4): (0.01-0.08): (0.01-0.06): (0.01-0.08): (10-80):

10.

3. The method for preparing a high melt strength polypropylene according to claim 1 or 2, characterized in that: The initiator is one or more of dicumyl peroxide, dibenzoyl peroxide, azobisisobutyronitrile, tert-butyl perbenzoate, bis(2-phenylethoxy) peroxydicarbonate, dicyclopentadiene and ammonium persulfate.

4. The method for preparing a high melt strength polypropylene according to claim 1 or 2, characterized in that: The interface agent is one or more of benzene, toluene, xylene and cyclohexane; the comonomer is styrene and / or acrylic acid.

5. The method for preparing a high melt strength polypropylene according to claim 1 or 2, characterized in that: The main antioxidant is tetrakis[B-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester, B-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate n-octadecyl alcohol ester, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 1.

1. One or more of 3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane and bis(2,4-di-tert-butylphenol)pentaerythritol diphosphite; the auxiliary antioxidant is one or more of tris(2,4-di-tert-butylphenyl phosphite), triphenyl phosphite, trinonylphenyl phosphite, dilauryl thiodipropionate and octadecyl thiodipropionate.

6. The method for preparing high melt strength polypropylene according to claim 1, characterized in that: The swelling temperature is 40-80°C, and the swelling time is 20min-5h.

7. The method for preparing high melt strength polypropylene according to claim 1, characterized in that: The solvent used for soaking is one or both of anhydrous ethanol and deionized water, and the soaking time is 1 to 12 hours.

8. The method for preparing high melt strength polypropylene according to claim 1, characterized in that: The organic solvent used for extraction is acetone, and the extraction time is 2 to 36 hours.

9. The method for preparing high melt strength polypropylene according to claim 1, characterized in that: The drying temperature is 35-70℃.

10. Use of a high melt strength polypropylene prepared by the preparation method according to any one of claims 1 to 9, characterized in that: The high melt strength polypropylene is used in the fields of packaging, light industry, construction, electronics, electrical appliances and automobiles.

Images